volume 24 2021 the libyan journal of science

Volume 24 2021

THE LIBYAN JOURNAL

OF SCIENCE (An International Journal)

Published by

FACULTY OF SCIENCE

UNIVERSITY OF TRIPOLI

ii

Volume 24 2021

______________________________________________________

THE LIBYAN

JOURNAL


Published by the FACULTY OF SCIENCE


iii

MEMBERS OF THE EDITORIAL BOARD

KHALED M. OUN (Editor-in-Chief)

Department of Geology, Faculty of Science,

University of Tripoli, Libya.

MOHAMED E. KELABI (Electronic Copy Coordinator)

Department of Physics, Faculty of Science,


TAWFIK A. BULATI

Department of Mathematics, Faculty of Science,


ALI A. EL-MAKHROUF

Department of Geology, Faculty of Science,


RAMADAN M. ELMEHDAWI

Department of Chemistry, Faculty of Science,


HASSAN A. MAGHRABI

Department of Zoology, Faculty of Science,


iv

THE LIBYAN JOURNAL


Peer reviewed international journal of science, published

biannually by the Faculty of Science, University of Tripoli.

Volume 24, 2021

Published by the

FACULTY OF SCIENCE


v

Papers should be submitted to the, Editor-in-Chief, any

member of the Editorial Board or the Journal Secretariat.

All correspondence should be addressed to: Editor-in-Chief The Libyan Journal of Science, Faculty of Science, University of Tripoli, P.O.Box 13178, Tripoli-Libya.

ISSN 0368-7481 (Print) ISSN 2521-3822 (Online)

E-mail: [email protected] Tel: 00218-21-7138882 URL: http://libyanjournal.atspace.co.uk Copyright © Faculty of Science, University of Tripoli, Libya No part of this journal may be reproduced in any form without written permission from the copyright holders.

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المجلة الليبية للعلومThe Libyan Journal of Science

مجلة علمية دولية محكمة تصدر مرتين في السنة عن كلية العلوم بجامعة

طرابلس.

هيئة التحرير

أ.د. خالد محمد عون )رئيس التحرير(

الكلابي )منسق النسخة الالكترونية( يأ.د. محمد إمحمدعل

أ.د. توفيق عبدالسلام البولاطي

أ.د. علي أحمد المخروف

أ.د. رمضان محمد المهدوي

أ.د. حسن أحمد المغربي

viii

THE LIBYAN JOURNAL OF SCIENCE

(An International Journal)

Volume 24 2021

CONTENTS

BIOLOGY

Taher Y. Abourghiba, Mohamed T. Almskat, Alya H. Duzan

and Maha A. Elsabri, Ebtisam A. Abudaya

Study of Dermatophytosis Prevalence in Patients Attending Dermatology Clinic at

Tripoli Central Hospital…………………………...………………………………..

صالح الشريف وعيسى صالح فرج ,علي أبوالقاسم العاقل ,يونس حاتم مصطفى

على انخفاض محتوى Fusarium solaniتأثير الإصابة بمرض عفن الجذور الجاف المتسبب عن فطر الكربوهيدرات بجذور الحمضيات في شمال غرب ليبيا…………………………………………………

Taher Y. Abourghiba, Mohammed A. Almsalati, and Zynab A. Alghadem

Investigations of the Prevalence of Candida Infections in Diabetes Mellitus

Patients in Tripoli.........................................................................................................

Saleh Isslugi and Ali A. Elagael

The Effect of Mechanical Scarification on Seed Germination

of Helianthemum lippii (L.) Dum.Cours……………………………………………...

Entisar Mohamed Eljaziri and HishamAddin Bin Omar

Biology and Growth Performance for Fry Red Tilapia Feed With Spirulina………….

و بثينة مصطفى الصغير السلام محفوظنوال عبد

خنفساء السمية النباتية للزيوت العطرية الأساسية ومسحوق الأوراق لأربعة نباتات طبية على البالغات ويرقات Tribolium confusum Duval (Coleoptera: Tenebrionidae) الدقيق المتشابهة…………………

CHEMISTRY

Anour Shebani, Abdalah klash, Rabia Elhabishi, Shalh Abdsalam, Wael Elhrari

Effects of Blend Composition on the UV Stability of Polyethylene Blends…………..

MATH

Zohra Farnana

Sobolev Spaces in Metric Spaces……………………………………………………...

PHYSICS

1

9

19

31

39

55

65

79

ix

محمد القاضي الصادق و الهادي الزوام، دلنده محمد ناصفنجاة سالم الشفتري سعاد محمد بوقرين، عياد IBM-2 المتفاعلة البوزونات نموذج باستخدام شفعية–الشفعية 𝐸𝑟162−156 نظائر خصائص دراسة………

Sedig S. Farhat

Use of Finite Difference Time Domain (FDTD) Technique to Calculate Poynting

Vector in Free Space with Obstacles in Computational Domain……………………...

SHORT NOTE


Effect of Feeding Fry Red Tilapia with Spirulina on Fish Health……………………..

Suggestions to Authors…………………………...…………………….………

……………..…………………..……………………………………تعليمات النشر

89

101

119

125

129

1

The Libyan Journal of Science (An International Journal): Volume 24, 2021

Study of Dermatophytosis Prevalence in Patients Attending

Dermatology Clinic at Tripoli Central Hospital

Taher Y. Abourghiba1, Mohamed T. Almskat, Alya H. Duzan2, Maha A. Elsabri3, and

Ebtisam A. Abudaya4

Department of Botany, Faculty of Science, University of Tripoli, Libya [email protected]; 2Alyaduzan@yahoo, [email protected],

[email protected]

Abstract The current study was performed to determine the prevalence of superficial fungal

infections among patients attending Dermatology Clinic at the Tripoli Central hospital. A

total of 212 cases were selected with an age range 7-75 years. They were tested for fungal

skin infections using microscopic and laboratory methods. The Results demonstrated that

all patients had dermatophytes infections. Tinea ungium was the most common type of

clinical infections (39.34%), followed by Tinea capitis (31.14%), Tinea pedis (22.13 %)

and Tinea faciei (7.37 %). The results indicate that Trichphyton violacenm was the most

common etiological agent of dermatophyte infection (59.01%) followed by Microsprum

canis (20.49%) Trichophyton rubrum (12.29%), Epidermophyton floccosum (4.09%) and

Trichophyton menagrophtis (3.27 %). The findings of the current study showed that higher

prevalence of dermatophytes was higher in rural areas than urban areas.

Keywords: dermatophytes, Tinea infection; Microsporum; Trichophyton;

Epidermophyton; Libya.

المستخلصاجريت الدراسة الحالية لتحديد مدى انتشار الاصابات الفطرية السطحية بين المرضى الذين كانوا يترددون على عيادة

سنة( و اختبرت 77-7بين )حالة تراوحت اعمارها 211تم اختيار .بمستشفى طرابلس المركزي الأمراض الجلدية

هذه الحالات المصابة باستخدام الفحص المجهري للعينات والطرق المعملية. أظهرت النتائج أن جميع الحالات تعاني

( ، تليها سعفة الرأس ٪93.93من اصابات فطرية جلدية وكانت سعفة الاظافر أكثر أنواع الاصابات شيوعا )

( .واظهرت نتائج هذه الدراسة اوضحت ان %7.97( وسعفة الوجه )% 11.29( , سعفة القدم )92.23٪)

( يليه فطر % 73.92كان من اكثر الفطريات المسببة للإصابات الجلدية بنسبة ) Trichophyton violacenmفطر

Microsporum canis ( ثم فطر % 19.33بنسبة )Trichophyton rubrum ( يليه فطر % 21.13بنسبة )

Epidermophyton floccosum ( وفطر % 3.93بنسبة ) Trichophyton menagrophtis ( 9.17بنسبة

اطق لريفية مقارنة بالمن(, كما بينت نتائج الدراسة ان نسبة الاصابة بالأمراض الجلدية كانت اعلي في المناطق ا%

.الحضرية

Accepted for Publication 20/6/2021.

2

Taher Y. Abourghib, Mohamed T. Almskat, Alya H. Duzan and Maha A. Elsabri, Ebtisam A. Abudaya

Introduction

Infections caused by many fungi can be divided into three groups: systemic mycosis,

superficial mycosis and subcutaneous mycosis. Among superficial infection,

dermatophtes is the common infection caused by fungi known as dermatophytosis .The

dermatophytes are a group of fungi that are able to damage and utilize keratin found in

the skin, hair, nails, horns and feathers (Grumbt et al., 2013). Evidences indicate that

dermatophyte fungi are one of the most efficient human parasites, due to their efficiency

in invading keratinous tissues (Zarrin et al., 2011). Dermatophytes are classified into three

genera of pathogenic fungi; Epidermophyton, Microsporum and Trichophyton. The

dermatophytosis transfers to humans from animals (zoophilic) and from soil (geophilic)

or through direct infection by personal contact (Anthropophilic) (Aho, 1988).

Dermatophytes have been recorded all over the world and become a public health problem

in many parts of the world especially in developing countries (Nweze and Eke, 2016).

Havlickova et al. (2008) and Blanka et al. (2008) have reported that 20–25% of the world's

population has skin mycoses and appeared to be a frequent form of infection. Infection of

nails, toes and skin by non-dermatophytes Candida and some molds have been increasing

(Satpathi et al., 2013). The Aim of this study is to isolate and identify the fungal agents

from clinical samples causing dermatophytosis in patients.

Materials and Methods

This study was conducted at the Department of Botany, Faculty of Science, University

of Tripoli. The study involvedpatients that are clinically diagnosed for superficial

mycosis. Patients data were recorded using standard format. A total of 122 samples were

collected from patients attending the dermatology clinic in Tripoli Central Hospital from

October 2018 to September 2019 with age range of 7-75 years. Samples were taken from

skin, nails and hair by a sterile razor blade and sterile scissors. All samples were placed

in labelled sterile vials and transported to the Mycologicy Lab. Specimens were

examined and treated with 10% KOH. Specimens of nails were examined after mounting

with 20% KOH for 24 hours and then examined. Each specimen was placed on a drop of

KOH solution using sterile forceps and cover slip was placed on the slide.

Isolation and Culture Method

Each scraping was cultured using Sabrourad Dextrose Agar (SDA) containing 0.05 g/ml

of cyclohexamide and Chloramphenicol. The plates were incubated at 25°C and were

examined twice a week for perpetually up to 3 weeks. Fungal isolates were sub-cultured

on the plates of SDA and were examined microscopically for morphological

characteristics.

Results

In this study, the 122 scrapings collected from suspected cases of dermatophytosis, 56

cases (45.90 %) were female and 66 (54.09%) from male patients’ skin infected patients.

3

Study of Dermatophytosis Prevalence in Patients Attending Dermatology Clinic

The etiological agents of dermatophycoses recorded in this study are Trichophyton

violacenm was the predominant fungal species (59.01 %) followed by Microsprum

canis (20.49 % ), Trichophyton rubrum (12.29 %), Epidermophyton floccosum (4.09 %)

and Trichophyton menagrophtis (3.27 % ) ( Table 1and Fig. 1).

Table 1. Number and percentage of dermatophytes isolates

No. Isolated species No of isolates In percentage

1 Microsprum canis 26 20.49 %

2 Trichophyton menagrophtis 4 3.27 %

3 Trichophyton rubrum 15 12.29 %

4 Trichophyton violacenm 72 59.01 %

5 Epidermophyton floccosum 5 4.09 %

Total 122 100 %

Fig. 1. Percentage of dermatophtes isolates

The prevalence rates of fungal infections with veneration to Tinea types Table 2 and

Fig. 2) involved: Tinea capitis (31.14%), Tinea pedis (22.13 %), Tinea ungium

(39.34%), and Tinea faciei (7.37% ).

Table 2: Number and Percentage of Tinea types

Tinea types Number Percentage) %(

T. capitis 38 31.14%

T.pedis 27 22.13%

T. unguium 48 39.34%

Tinea faciei 9 7.37%

20.49%

3.27%

12.29%

59.01%

4.09%

Microsprum canis

TrichophytonmenagrophtisTrichophyton rubrum

TrichphytonviolacenmEpidermophytonfloccosum

4


Fig. 2. Number of Tinea types

As shown in (Table 3 and Fig.3) the infection by dermatophytes was significantly higher

with ages between 15- 30 years (43.4%). In contrast the percentage of infection was lower

in other age groups as the following less than 15 years (12.2 %) 31-45 years(18.8 %), 46-

61 years (13.9 %) and more than 61 years (11.4 %) .

Table 3. Distribution of dermatophytes fungal infections according to the age of patients.

Age groups Frequency Percentage

˂25 15 12.2 %

15- 30 53 43.4%

31-45 23 18.8 %

46-61 17 13.9 %

˃61 14 11.4 %

Results of this study have shown that the highest percentage of dermatophytes infection

in the rural areas were Tinea ungium (55.73 % ), Tinea capitis (27.94 %), Tinea pedis

(22.05%) and Tinea faciei (8.82%) while in urban areas the fungal infections were found

to be as the following Tinea ungium (37.03 %), Tinea capitis (35.18 %), Tinea pedis

(22.22) and Tinea faciei (5.55 %).The number of infection was higher in rural areas

compared to urban areas table 4 and 5) .

Table 4. Distribution of dermatophytes infections based on residence area (rural and urban

areas)

Residence areas Frequency Percentage (%)

Rural areas 68 55.73 %

Urban areas 54 44.26 %

Total 122 100 %

0

10

20

30

40

50

60

T. capitis T.pedis T. unguium Tinea faciei

Nu

mb

er

of

Tin

ea

typ

es

Tinea types

5


Fig.3. Distributions of dermatophytes fungal infections according to the ages of patients

Table 5. Distribution of the Tinea infection according patient’s residence.

No Tinea types

Urban areas Rural areas

No. of patients % of

infection

No. of patients % of

infections

1 Tinea ungium 29 37.03 12 41.17

2 Tinea pedis 21 22.22 27 22.05

3 Tinea faciei 9 5.55 6 8.82

4 Tinea capitis 23 35.18 23 27.94

Total 54 Total 62

Discussion

In this study 122 patients suffering from dermatophytes infection were selected, in

which Tinea ungium was the predominant type of infection (41.17%), Tinea capitis was

the second common infection (27.94% ), followed by Tinea pedis (22.05%) and Tinea

faciei (8.82 %). The higher prevalence of infection between toes could be was attributed

to the fact that they are exposed to sweating more than other parts of the body which helps

the spread of the infection. The occurrence of Tinea infection was higher in 15 to 30 years

(43.4% ) age group followed by 31-45 years (18.8 %),46-61 years (13.9 %), less than 15

years (12.2 %) and >61 years (11.4 %). Similar observations were reported by Sarma and

Borthakur (2007) and Kansra et al. (2016). In our study, four different types of Tinea were

observed among which tinea ungium was the dominant infection accounting for 39.34%

of the total infections. Results of this study revealed that dermatophytes affect all ages

and sexes. Similar findings were observed in previous studies (Evans and Gentles ,1985;

Adefemi et al., 2011). In the current study, Trichophyton violacenm represents a

significant percentage of dermatophyte isolates. Our finding was similar to several studies

0

10

20

30

40

50

60

˂15 15- 30 31-45 46-61 ˃61

%

Age groups

6


(e.g. Woldeamanuel et al.2005; Ali-Shtayeh et al., 2002; Ameen,2010). In this study the

distribution of infection by residence was 55.73 % rural areas and 44.26 % inurban areas.

Although there was no significant association between infection and residence, more

people in rural areas seemed to be infected than those in urban areas which may be due

to prolonged exposure to soil in rural areas and have frequent encounter with animals and

less hygiene standard of living. Cohen and Powdery (2004) reported that fungal infections

are often associated with animals. In the present study persons of all age groups were

susceptible to dermatophytosis but it appeared to be less common in age group over 61

years (11.4 % of all cases).

Conclusion and Recommendation

The present study has indicated that Tinea unguium was the dominant clinical infection

involving 39.34% of the total cases of dermatophytosis. of the total number of patients

(122). Dermatophyte isolates Trichphyton violacenm was the predominant fungal species

(59.01 %).

There is a need for further hospital survey involving large number of patients to

ascertain any association between residence, age, gender and infection.

References

Adefemi, S. A., Odeigah. L. O. and Alabi, K. M. (2011). Prevalence of dermatophytosis

among primary school children in Oke-oyi community of Kwara state, Nigerian

Journal of Clinical Practice, 14(1), 23–28.

Aho, R. (1988). Mycological studies on zoophilic dermatophyte isolates of Finish and

Swedish origin Mycoses, 31, 295–302.

Ali-Shtayeh M. S., Salameh A. A., AbuGhdeib S. I., Jamous R. M. and Khraim, H.

(2002). Prevalence of Tinea capitis as well as of asymptomatic carriers in school

children in Nablus area (Palestine). Mycoses, 45, 188-194.

Ameen M. (2010). Epidemiology of superficial fungal infections. Clinics in Dermatology,

28(2), 197–201.

Blanka, H., Czaika V. A. and Friedrich A. (2008). Epidemiological trends in skin mycoses

worldwide Mycoses, 51, 2–15.

Cohen, J. and Powdery, W. G. I. (2004). Infectious diseases. Mosby Edinburgh London

NewYork (1): 173—179, (2) :2341-2353.

Evans, G. V. and Gentles, J. C. (1985). Essentials of Medical Mycology. Churchill

Livingstone.

Grumbt, M., Monod, M., Yamada T., Hertweck C., Kunert, J. and Staib, P. (2013).

Keratin degradation by dermatophytes relies on cysteine dioxygenase and a sulfite

efflux pump ,J. Invest. Dermatol., 133, 1550–1555.

Havlickova B., Czaika V. A. and Friedrich M. (2008). Epidemiological trends in skin

mycoses worldwide. Mycoses, 51(4), 2–15.

7


Nweze, E. I. and I. Eke, I. (2016). Dermatophytosis in northern Africa, Mycoses, 59(3),

137–144.

Satpathi, A. Achar, D. Banerjee, A. Maiti, M. Sengupta, and A. and Mohata (2013).

Onychomycosis in Eastern India - study in a peripheral tertiary care centre, Journal

of Pakistan Association of Dermatologists, 23(1),14–19, 2013

Sarma, S. and Borthakur, A. K. (2007). A clinico-epidemiological study of

dermatophytoses in Northeast India. Indian J Dermatol Venereol Leprol., 73(6),

427-8 .

Zarrin, M. , Poosashkan, M., Mahmoudabadi , A. and Mapar, M. ( 2011). Prevalence of

Superficial Fungal Infection in Primary School Children in Ahvaz, Iran.

Macedonian Journal of Medical Sciences. 4, 89-92

Woldeamanuel Y., Leekassa R., Chryssanthou E., Menghistu Y. and Petrini B. (2005).

Prevalence of tinea capitis in Ethiopian schoolchildren. Mycoses, 48(2), 137–141.

9


Fusarium solaniتأثير الإصابة بمرض عفن الجذور الجاف المتسبب عن فطر على انخفاض محتوى الكربوهيدرات بجذور الحمضيات في شمال غرب ليبيا

عيسى صالح فرج و ،صالح الشريف ،علي أبوالقاسم العاقل ،يونس حاتم مصطفى

ليبيا، جامعة طرابلس-الزراعةقسم وقاية النبات، كلية [email protected]

المستخلصر هم الأسباب الإصابة بفطأن من ا و ،بشکل ملحوظ ايبيل يف الحمضياتلانخفاض انتاج ةيمن الدراسات المحل ديأشارت العد

Fusarium solani ن الفطر أ ،المختبريمسببا لها تعفن الجذور الجاف. أظهرت نتائج العزلF. solani هو المسبب لمرض مضياتالحعلى مرض تعفن الجذور الجاف لأشجار الحقليالمسح نيوقد ب ا،يبيل يف الحمضياتتعفن الجذور الجاف لأشجار

مناطق ميعج يغربا، انتشار المرض ف ةيمن مصراته شرقا وحتى الزاو ة يبدا ايبيشمال غرب ل الحمضياتعدة مناطق لزراعة يف ديرتق يف معنويةأظهرت النتائج وجود فروقات ة،الجذور للنباتات المصاب ناتيع يف F. solaniتلازم وجود فطر الدراسة مع

لمطيافاباستخدام الامتصاصية بقياسحسبت التيجذور الشتلات المعاملة بعزلات مختلفة من الفطر يف اتيالسکر ةيکم ويعزى. %17 يوصل الى نسبة حوال ات،يمحتوى الجذور من السکر يقد سببتا أعلى انخفاض ف F5و F4العزلتان ،یالضوئ

أعداد زيادةتؤدى إلى يتطور قشرة الجذور والت يمهما جدا ف عتبري يالذ الجلوكوزالفطر على سکر لتغذيةهذا الانخفاض منطقة الجذور. يجدا ف رةيالفطر بصورة کب

Low Carbohydrate Content in the Roots of Citrus as an Indicator of

Being Infected with Dry Root Rot Disease Caused by Fusarium solani

in Northwestern Libya

Hatem Younis, Ali Elagael, Saleh Elsherif ana Issa Saleh Farag

Plant Protection Department, Faculty of Agriculture, University of Tripoli, Libya.

Abstract The field survey on the dry root rot disease of citrus trees of citrus –growing areas in several

regions of northwestern Libya from Misrata to Zawia, showed spread of the disease in all

areas of this study associated with the presence of Fusarium solani in infected citrus plants.

The study found significant differences in impact on the carbohydrate contents of roots of


11

صالح الشريف وعيسى صالح فرج العاقل،علي أبوالقاسم مصطفى،يونس حاتم

seedlings infected with different isolates of F. solani. isolates, F4 and F5 have the highest

effect on the root contents of sugars. Also the fungus numbers were higher in the

rhizosphere.

Keywords: wilt diseases; Fusarium solani; citrus trees; Libya.

المقدمة

الحمضيات المساحة الإجمالية المزروعة بأشجار أهم اشجار الفاكهة في ليبيا وتقدر إحدىلحمضيات ا أشجار تعتبرطنا سنويا حسب إحصائيات ألف 50هكتار معظمها على الساحل الليبي، وكمية الإنتاج حوالي 0077 بحوالينيماتودا مراض المتسببة عن الفيروسات، الالأملوحة المياه و نتيجة بدرجة كبيرة. لكن انخفض انتاج الحمضيات 1772

. (Younes, 2009) والفطريات

ويعتبر واسع الانتشار (Sacc, emend. Snyd. & Hans) (Mart.) Fusarium solani فطر الفيوزاريومإن ,.Fahmy, 1923; Booth, 1971; Bereneuza et al)العوائل النباتيةلعدة أمراض للعديد من المسبب الرئيسي

2004; Mansoor and Kord 2006). ،أشجار الحمضيات من ضمنها و ،1997، والمغربي(Nemec et al.,

1980; Kore and Mane, 1992; El-Mohamedy; 1998; Catara and Polizzi, 1999;). والموتفطر وتكمن خطورة. .(Martin, 1949)لبادرات أو شتلات الحمضيات ”Citrus Suaaen Death“ المفاجئ

F. solani الحمضيات ية المغذية لأشجارجذر الجذور وخاصة الشعيرات ال يصيبفي كونه (Baker et al.,

1981; Graham et al., 1983; Lindbeck and Brlansky, 2000). مما يؤثر على أشجار الحمضيات السليمة فيحدث لها ذبول فجائي نتيجة تعفن الجذور ومن ثم موت النبات.

دلة كافية لدعم الرابطة بين التعرض للمرض والمستويات المنخفضة للكربوهيدرات فى عدد من أهناك كما أن solaniالمتسبب عن فطرet al., 1992) (Labuschagne الجاف صابة بمرض تعفن الجذورمنها الإ المحاصيل.

Fusarium.

الحمضيات في ليبيا كالدراسة التي قام بها لأشجارمراض الفطرية يوجد قدر محدود من البيانات المتاحة حول الأDamiano لمرض التعفن البني على الليمون وتعفن القدم على ا واسع االتي اظهرت انتشار (،2657) وآخرون

شجار الحمضيات أصابة إ( سجل 2009) وآخرون Younes ،الحمضيات. علاوة على ذلكصناف مختلفة من أ سبب في المنطقة الغربية من ليبيا F. solaniالمتسبب عن فطر تتعفن الجذور الجاف لأشجار الحمضيابمرض

شجار الحمضيات. كبير لأفى تلف لم تسجل أي دراسات سابقة في ليبيا حول تأثير الإصابة بمرض تعفن الجذور الجاف على المحتوى الكربوهيدراتي

بوهيدراتي على المحتوى الكر وتأثيره هذا المرضتحديد دور لمعرفة و هدفت هذه الدراسة لجذور أشجار الحمضيات. لذا ليبيا.في بعض مناطق شمال غرب لجذور شتلات الحمضيات المصابة

11

على انخفاض محتوى الكربوهيدرات Fusarium solaniتأثير الإصابة بمرض عفن الجذور الجاف المتسبب عن فطر

المواد وطرق البحث

المسح الحقليحتى نهاية شهر 1770تم إجراء المسح الحقلي لبساتين الحمضيات خلال الفترة من بداية شهر مايو

يع، عين وادي الرب غرب ليبيا )الدافنية، قصر الاخيار، العلوص، القره بوللي،غلب مناطق شمال أفي 1770ديسمبر ضانتشار مر لغرض التعرف على مدى والزاوية( جودائمزاره، الكريمية، العزيزية، قصر بن غشير، الزهراء، الطويبية،

.في هذه المناطق في بساتين الحمضياتحجم المشكلة التعفن الجاف للجذور و

المرضي بالمسب عزلفن عتالبظهرت عليها علامات الاصابة التي الحمضيات لخمسة أشجار من المغذية جذورمن العينات جمعت

شملتها الدراسة. التي مواقع عدة للجذور منالجاف سم وغسلت 7.0، وقطعت بحجم شجار الحمضيات المصابةلأ المغذية جذورالعزل المسبب المرضي من تم

دقائق، 3لمدة % 7.0تركيزه (NaOCl)الصوديوم سطحيا بغمرها في محلول هيبوكلورايت وعقمتبالماء الجاري واسطة بوغسلت بالماء المقطر والمعقم للتخلص من محلول التطهير وجففت القطع بين ورقتي ترشيح معقمتين ونقلت

الوسط من 3سم 17-20من حوالي على سم يحتوي 5.0قطع في كل طبق بتري قطره 4ملقط معقم وزرعت بواقع ملغم. 177المضاف اليه المضاد الحيوي تتراسيكلين بتركيز (PDA) المغذي أجار ديكستروز البطاطس

مكررات من أطباق 3أيام، وعمل لكل عينة جذور 0-0من لفترة م01º ±1عند درجة حرارة الأطباق حضنت الخيط بطريقة عزل طرف وتنقيتهاية حول القطع المعزولة، النموات الفطرية الناموبعدها تم إجراء فحص التنمية.

وعرف PDA) )ثم حفظت العزلات في انابيت اختبار تحوي الوسط المغذي (Hyphal tip method) الفطريلمستوى الجنس والنوع اعتمادا على صفات المستعمرة الفطرية وطبيعة الغزل الفطري والأبواغ والتراكيب التي الفطر (. 2653) وآخرون Nelson و Booth، (1971)العالم وفق ةباستخدام المفاتيح التصنيفيتكونها

مراضية اختبار الإ

تم الحصول عليها من مناطق مختلفة اعطي لها رموز F. solaniعزلات مختلفة من الفطر 5 إمراضيهاختبرت (F1،F2 ،F3 ،F4 ،F5 و(F6، تركيزفي ماء مقطر بعلى حده الفطر لكل عزلة أبواغعملت معلقات من حيث بادرات نارنج )الشفشي( بعمر شهر واحد 0مل ماء مقطر. تمت العدوى الاصطناعية على 2بوغ / 527× 2

لى إ، نقلت بعدها Elaraby ،(2650) حسب طريقةساعة، 14بغمرها في معلق الفطر لمدة منماة بتربة معقمة،أخرى بادرات 0غمرت بادرات بينماعلى الالذبول أعراض ظهور حينلى إسابيع أث صص الغرس وتركت لفترة ثلاأ

في ماء مقطر كشاهد.

12

صالح الشريف وعيسى صالح فرج ،علي أبوالقاسم العاقل ،يونس حاتم مصطفى

ى الكربوهيدراتي في جذور الشتلاتتحديد المحتو على المحتوى الكربوهيدراتي لجذور شتلات الحمضيات المصابة، وتأثيره تعفن الجذور الجاف مرض د دوريلتحد

شتلات النارنج )الشفشي( لكل 27جمعت جذور حيث . (Willis ،2373و (Yemmاستخدمت طريقة الأنثرونبالماء ثم جففت جيدا وطحنت باستعمال الخلاط الستة، وغسلت F. solaniلفطر ا على حده من عزلاتمعاملة

107أضيف إليه ،مل 077دورق قياسي حجمه عينات/معاملة( في 27)جرام من كل عينة 2وضع الكهربائي، جم من 12.5: تم تحضيره بخلط Aمحلول الترويق ( "B و Aمل لكل من محاليل الترويق ) 20مل ماء مقطر و

محلول و قطرمل ماء م 277في Acetic acid))مل حمض الخليك 3مع (Zinc Acetate)بلورات خلات الزنك في (Potassium Ferro cyanide) جم من بلورات سيانيد حديد البوتاسيوم 27.5: تم تحضيره بخلط Bالترويق

دقيقة، 37ثم تركت لمدة ،مل مع الرج عدة مرات 077أكمل الحجم بالماء المقطر إلى ."مل من الماء المقطر 277تحليل تم ، و ,µm) (Whatman no.1 11ميكرون 22جم ، بح2رقم رشح المحلول بواسطة ورق ترشيح واتمان

جم 7.1 بإذابة (Anthrone)العينات للكشف عن إجمالي السكريات غير التركيبية باستخدام طريقة الأنثرون .(Willis ،2604و (Yemm%65مل من حمض الكبريتيك المركز 277أنثرون في

مل من الأنثرون، 4مل من مستخلص الجذور لكل معاملة بعد إجراء عملية الترويق وأضيف إليها 1أخذ تغير لون المستخلص إلى اللون الأزرق. )إذا كان اللون غامق جدا يتم تخفيف العينة بالماء المقطر(، ترك لملاحظة

تقاس كثافة اللون المتكون بواسطة جهاز ، طيافمل منه الى الأنبوبة المخصصة لجهاز الم 2المحلول ليبرد، أضيف وسجلت القراءة لكل عينة. قبلها تم ، نانومتر 517عند الطول الموجي Spectrophotometerالضوئي المطياف

ليها سابقا. إباستخدام الخطوات المشار Blankمعايرة جهاز المطياف الضوئي باستخدام العينة القياسية ات في لمعرفة تركيز السكريالمستقيم رسم الخط و ية من سكر الجلوكوز معلومة التركيز ضرت محاليل قياسح

مل ماء مقطر وذلك للحصول على محلول تركيزه 277جم من الجلوكوز في 2أذيب حيث العينات المراد اختبارها من % 7.772مل ماء مقطر للحصول على التركيز 07مل ووضع في دورق يحتوي على 0، أخذ منه % 7.72

مل ماء مقطر 07ووضع في دورق يحتوي على 7.72مل من المحلول الذي تركيزه 5المحلول القياسي. ثم أخذ مل 07به ووضع في دورق 7.72مل من المحلول الذي تركيزه 0. ثم أخذ % 7.7721للحصول على التركيز

. ثم % 67.772 على التركيزللحصول . وهكذا تتبع نفس الطريقة% 7.7724ماء مقطر للحصول على التركيز .وضعت العينات في أنابيب المطياف وسجلت القراءات

والمناقشة النتـــائج

، التدهور، وجفاف الأوراق وتساقطها، أعراضا للذبول، و F. solaniشجار البرتقال المصابة بالفطر أأظهرت و أخرون Kuntaونخر الجذور، وتغير اللون الى الأرجواني للخشب، و موت قلف الاشجار، وهذا يتوافق مع وصفه

( في وصفهم لأعراض الاصابة بهذا الفطر على أشجار البرتقال في ولاية تكساس بالولايات المتحدة. 1927)

13


هو المسبب لمرض تعفن الجذور الجاف لأشجار F. solani الفطر نالمختبري، أ العزل نتائج وقد بينتاختبار ثبتأ الدراسة وقدمن جميع المناطق التي شملتها به،من جميع العينات المصابة الحمضيات في ليبيا، إذ ع زل

,Kore and Mane) ن هذا الفطر هو المسبب لهذا المرض وهذا يتوافق مع الدراسة التي قام بهاأ الإمراضية

1992; Catara and Polizzi, 1999; El-Mohamedy and Hasabo, 2005; Kunta et al., 2015). والحمضيات الزيتون، عن تعفن الجذور ومرض الذبول في العديد من مشاتل الجوافة في هذه الدراسات تم الكشفحيث

.% 41(، ووصلت نسبة الإصابة بهذا المرض في البعض منها الى حوالي 2)شكل

.مناطق شمال غرب ليبيافي أحد أعراض مرض الذبول على أشجار الحمضيات. 2شكل

14


لعوامل ا لأشجار المجهدة بسببتزداد في اتعفن الجذور و جفافوشدة ارتفاع نسبة بعضها أيضا أن وأظهرت روف مثالية ظبالأشجار النامية تحت صرف سيئة، مقارنةعلى سبيل المثال الأشجار التي تنمو تحت ظروف البيئية،

(.1727) وآخرون Elagaelوهذا يتوافق مع الدراسة التي قام بها سبتح على المحتوى الكربوهيدراتي في جذور شتلات الحمضيات المصابة، F. solaniلتحديد تأثير فطر

، لرسم المنحنى (2المطياف الضوئي )جدول مباستخداالتراكيز القياسية لسكر الجلوكوز وتم قياس الامتصاصية (. 3القياسي )شكل

امتصاصية المحلول القياسي لتراكيز معلومة من سكر الجلوكوز. 2جدول

والذي (،1الشاهد )جدول ، وكذلكF. solaniفطر السجلت قراءة الامتصاصية لعينات الجذور المعاملة بعزلات (. 1السكريات غير التركيبية في المعاملات )جدول ز تم من خلاله حساب تركي

لجذور )شكل ل الجافوزن من الجم 2 /وبمعرفة التركيز أمكن حساب كمية السكريات غير التركيبية بالملجم 4.)

نج جذور شتلات النار في محتوىأظهرت نتائج التحليل الإحصائي حسب اختبار دانكن وجود فروق معنوية عزلات( مقارنة مع جذور 5) F. solani)الشفشي( من السكريات غير التركيبية بعد معاملتها بعزلات مختلفة من

(. 3معاملة )شكل الالشتلات غير %02بنسبة السكريات،قد سببتا أعلى انخفاض في محتوى الجذور من F5و F4بينت هذه النتائج أن العزلتين

، هذا يتوافق %31بنسبة السكريات،أقل انخفاض في محتوى الجذور من F2مقارنة مع الشاهد. بينما سجلت العزلة ر الأساسي المستعم هيبدو أن F. solaniاستنتجوا أن (، حيث 2650) وآخرون ،Grahamمع الدراسة التي قام بها

كما يسبب في استنفاد المحتوى الكربوهيدراتي لها. الحمضيات اشجارلجذور

قراءة امتصاصية المحلول القياسي التركيز القياسي العيناتBlank 0.0004 0.316

1 0.0006 0.51 2 0.0008 0.611 3 0.001 0.623 4 0.0012 0.866 5 0.0014 1.051 6 0.0016 1.176

15


قياس الامتصاصية والتركيزات القياسية لمستخلص جذور الحمضيات المعاملة بعزلات مختلفة من فطر .1جدول F. solani .مقارنة بالشاهد

أظهرت نتائج التحليل الإحصائي لتجربة تقدير كمية السكريات في جذور الشتلات المعاملة بعزلات مختلفة من الفطر وجود فروقات معنوية بين العزلات في تأثيرها على محتوى الجذور من السكريات غير التركيبية عند المستوى

7.70 =a ( وذلك3شكل ) لفصل المتوسطات. اختبار دانكنحسب

تركيز السكريات الامتصاصية للعينات العينات المعاملة ببعض العزلات

9.99237 0.965 الشاهد بدون معاملة

F1 0.318 9.99937

F2 0.719 9.99937

F3 0.408 9.99977

F4 0.247 9.99917

F5 0.248 9.99917

F6 0.707 9.99927

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0 0.0005 0.001 0.0015 0.002

التراكيز

يةصصا

متالإ

.لحساب كمية السكريات غير التركيبية المستخدم قياسيالمنحنى ال .9شكل

y

Y

Y

التراكيز القياسية من سكر الجلوكوز

Y

R =0.942

16


على محتوى جذور شتلات الحمضيات المصابة من السكريات مقارنة F. solaniعزلات لفطر 5 تأثير .4شكل )المعاملات التي تحتوي على حروف متشابهة لا يوجد بينها فروقات معنوية(. . بالشاهد

-Nemec et al., 1989; Labuschagne et al., 1992; El) بهاوهذا يتفق مع الدراسة التي قام

Mohamedy and Hasabo, 2005). الذين ذكروا بأن هذا الانخفاض يكون بسبب تغذية الفطر على سكرالفطر إلى زيادة أعدادالجلوكوز تؤدى على تغذية الالجلوكوز الذي يعتبر مهما جدا في تطور قشرة الجذور. كما أن

بصورة كبيرة جدا في منطقة الجذور.

المراجع

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Baker, R. A., Tatum, J. H. and Nemec, S. (1981). Toxin production by Fusarium solani

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Bereneuza, T. R. V., Coimbra, M. R. M., Morais, M. A. and Oliveira, N. T. (2004).

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fingerprinting based on PCR markers. Braz. J. Microbiol., 35, 205-210.

Booth, C. (1971). The genus Fusarium. Commonwealth mycological Institute, Kew,

surrey, England. 237 pp.

Catara, A. and Polizzi, G. (1999). Dry root rot of citrus: Symptoms, causing and

susceptibility of rootstocks. Rivisto di Fruticolture, 6, 38-41.

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Italian and Arabic. 19pp.

17


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18


Yemm, E. W. and Willis, A. J. (1954). The estimation of carbohydrates in plant extracts

by anthrone. Biochemist. J., 57, 508–514.

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Department, Faculty of Agriculture, University of Tripoli, Tripoli-Libya). 91 pp.

19

Investigations of the Prevalence of Candida Infections in Diabetes

Mellitus Patients in Tripoli

Taher Y. Abourghiba1*, Mohammed A. Almsalati1, and Zynab A. Alghadem2**

1Department of Botany, Faculty of Science, University of Tripoli, Libya 2Biotechnology Research Centre, Tripoli, Libya

*[email protected]; **[email protected]

Abstract

This study was conducted on patients with diabetes who are suffering from immune

deficiency, and are most susceptible to opportunistic fungi, including Candida. In this study,

number of isolates of Candida were isolated from 104 diabetic cases between June and

September 2019 in the Diabetes Hospital in Tripoli. The study showed that 66.34 % of

patients suffer from the presence of Candida. Samples were taken with sterile cotton swabs

and cultured in Petri dishes containing the nutrient medium of Sabouraud Maltose Agar

(SMA). The dishes were incubated at 37o Ċ for a perioa of 72 hours. The fungal growth

samples were examined under a microscope to identify species of Candida. The highest

number of Candida was observed in vaginal swabs (32) followed by toe swabs (24) and nail

swabs (13).

Keywords: Candida infection; Diabetes Mellitus; Patients; Nails; Toes; Vagina; Libya.

المستخلصالاصابات الفطرية التي يسببها فطر المبيضات للمرضي المصابين بالسكري والذين يعانون من قصور في تضمنت هذه الدراسة

فطر المبيضات من هذه المسحات التي اخدت في عزلمسحة من اصابع القدمين واظافر الاصابع والمهبل. 401 اخدت المناعة.

المرضي الذين يترددون علي مستشفى السكر بطرابلس. اظهرت نتائج هذه الدراسة من 9042الفترة ما بين شهر يونيو واكتوبر

يليها (69اوضحت ان اكثر الاصابات كانت في المهبل )كما .من المصابين يعانون من الاصابة بفطر المبيضات %33.61ان

العينات بواسطة مسحات قطنية معقمة وزرعت في اطباق تحتوي على الوسط المغذي اخدت . (46( والاظافر )91ابيع القدمين )اص

ساعة. 14درجة مئوية لمدة 63حضنت الاطباق عند درجة حرارة و ،سابرويد مالتوز اجار

Introduction

Candidiasis is a common opportunistic infection that occurs in immune-compromised

individuals. It is also known as thrush and can cause yeast infections in many areas of the

body. Candidiasis is one of the most common diseases of human caused by several species

of Candida. These species live commensally on the skin, gastrointestinal tract in the

genitor-urinary tract and they are harmless in their human host when they do not overgrow

and interrupt the human immune system (Brown et al., 2007).

Accepted for publication: 17/6/2021

21

Taher Y. Abourghiba, Mohammed A. Almsalati and Zynab A. Alghadem

Under certain conditions, some species of Candida exploit the host body and cause

infection to several places in the human body, including the skin, nails, eyes, vagina,

lungs and toes. Candida takes advantage of the immune deficiency of some people such

as pregnant women, HIV-infected people, chemotherapy patients, diabetics, people who

use drugs and the user of immunosuppressive drugs and cancer patients (Kabir et al.

2012). Candida albicans is an opportunistic fungal pathogen that is responsible for

candidiasis in humans host, and it is responsible for about 70% of fungal infections around

the world (Morad, et al. 2018). Candida albicans is considered to be the most important

species among the other clinically significant species of Candida; accounting for more

than 70% of all yeasted isolated clinical samples (Eggimann, et al. 2003). Candida

albicans exists in two forms: in the form of yeast-like cells when incubated at a

temperature of 37° C, and as mycelium at a temperature of 25° C (Sudbery et al. 2004) .

Candida albicans can also form chlamydospores, round spores with thick walls (Chaffin

et al. ,1998). The pathogenicity of Candida species is attributed to certain virulent factors,

such as the ability to invade host defences, adherence, biofilm formation (on host tissue

and on medical devices) and the production of tissue-damaging hydrolytic enzymes such

as proteases, phospholipases and haemolysin (Silva et al., 2011). People with diabetes

are more likely to develop candidiasis because the elevated level of sugar in the body

provides nutrients for Candida and encourage its overgrowth (Barnett, 2004). Diabetes

mellitus is a chronic disease that can affect any organ of the body. One of the problems

associated with this condition is infection (Malazy et al., 2006).


This study was carried out in the Department of Botany, Faculty of Science, University

of Tripoli. Samples were collected through regular visits to the Diabetes Hospital in

Tripoli-Libya during the period from June to September 2019. 104 swab samples were

collected from vaginas, toes and nails from patients with diabetes. Samples were

transported to the Mycology lab. at the Department of Botany, Faculty of Science,

University of Tripoli. In the laboratory, 65 g of the test medium of Sabouraud Maltose

agar (SMA) was dissolved in 1000 ml distilled water and sterilized by autoclaving at

121ºC for 15 min. Antibiotic agent (Chloramphenicol) was added to the medium as pure

powder before sterilization of medium. Swabs were inoculated under aseptic conditions

on SMA. The plates were then placed in the incubator for 72 hours at a temperature of

37Ċ. Specimens of fungal colonies were stained by lactophenol and then mounted on

microscope slides. Identification of Candida species colonies were sub-cultured on

CHROM Agar medium (Willinger et al., 1999), and incubated at 37°C for 48 hours.

Candida isolates were identified by the detection of various colour characteristics on

CHROM agar plates. Species of Candida were identified as C. albicans, C. glabrata and

C. tropicalis. The data was subjected to statistical analysis using Statistical Package for

Social Science (SPSS).

21

Investigations of the Prevalence of Candida Infections in Diabetes Mellitus Patients in Tripoli

Results

We investigated 193 diabetic patients. The results were analysed according to their sex,

Candida and non-Candida infection, age, site of infection and species of Candida

isolated. Among these diabetic patients, 51 were male and 51 were female patients, 69

patients showed positive Candida infection and 35 patients did not (Table 1). The results

showed that Candida infection was higher in both female and male patients (66.345 %)

than non-Candida infection (33.652%) (Fig.1).

Table 1. Distribution of Candida and non-Candida infections among diabetic patients.

Gender Candida infection Non- Candida infection

number % number %

Female 44 42.3 11 10.5

Male 25 24.0 24 23.0

Total 69 66. 4 35 33.6

Fig. 1. Percentage of infection of Candida and a non-Candida in diabetic patients.

0

5

10

15

20

25

30

35

40

45

50

female male

Perc

enta

ge

Grender

Candida infection

Non-Candida infection

22


Table 2. Prevalence of Candida infection among patients with different ages.

age No. of Candida infection Percentage

30- 45 20 12.98 %

46 – 61 26 37.68 %

>61 23 33.33 %

Fig. 2. Percentage of Candida infection between age groups.

Among diabetic patients, the highest number of Candida was observed in vaginal swabs

(32) followed by toe swabs (24) and nail swabs (13). The value was not, however,

significantly higher in samples collected from vagina compared with ones collected toes

and nails as shown in Table 3 and Fig. 3.

Table 3. Frequency of Candida species isolated from diabetic patients

Isolated species Vaginal samples Toa samples Nail samples

Candida albicans 21 13 8

C. tropicalis 7 6 4

C. glabrata 4 5 1

Total 32 24 13

0

5

10

15

20

25

30

35

40

45

30-45 46 -61 >61

%

Age group

23


Fig. 3. Number of Cndida species isolated from infected sites.

As shown in Fig. 4. Candida albicans was the most prevalent species (73.91%)

followed by Candida tropicalis (15.94%) and Candida glabrata (10.14%). Statistical

analysis has revealed that the number of C. abicans was significantly higher than

C.tropicalis and C. glabrata (Table 4).

Table 4. Percentage of Candida species

Candida species Number Percentage

Candida albicans 51 73.91 %

Candida tropicalis 11 15.94 %

Candida glabrata 7 10.14 %

Fig. 4. Prevalence of Candida species.

0

5

10

15

20

25

vagina toes nails

Freq

uen

cy o

f C

an

did

a s

pec

ies

Sites of infections

C.albicans

C.tropicalis

C. glabrata

0

10

20

30

40

50

60

70

80

90

C.albicans C.tropicals C.glabrataCandida species

percenta…

24


The identification of Candida colonies is based on colour of colonies, light green as C.

albicans, blue as C.tropicalis and cream to white as C.glabrata (Fig .5).

Fig. 5. Growth of Candida species in CHROM agar medium C. albicans (4),

C.tropicalis (5) and C. glabrata (6).

A B

Fig. 6. Colonies of Candida albicans (A), germ tube formation of C.albicans (B)

Germ tube

25


Discussion

Candidiasis is the most common fungal infection and is responsible for 90% of the cases

of infectious vaginitis (Hedayati and Shafiei, 2010). Distribution of Candida species from

three different sites were also observed in this study. In study group 104 samples (Table

5) were collected from three different sites of the body of diabetic patients. Out of 69

positive samples, 71.01% of Candida was found in vaginal swabs, 15.94% in toe swabs

and 13.04% in nail swabs. In vagina acidic pH favours the growth of Candida and

increased glucose levels in genital tissues enhance Candida adhesion and growth. Vaginal

epithelial cells bind to Candida with greater propensity in diabetic patients than in non-

diabetic patients. The results of this study showed the relationship between prevalence of

Candida and age groups. We found that group age between 46 and 61 years and >61 were

higher because they are more susceptible to Candida infection, which is due to the decline

in the ability of their immune system. The study, revealed also that C.albicans was more

prevalent (73.91%) followed by C. tropicalis (15.94%) and C. glabrata (10.14 %).

Similar findings were observed in many previous studies (Muvunyi and Hernandez 2009;

Nelson et al., 2013; Faidh, 2013; Zisova et al., 2016; Abourghiba and Alghadem, 2020;

Tapper-Jones, et al., 1981).

Table 5. Details of the status of patients

No. Age blood glucose

Levels

Sex Sample ‘s site Type of

diabetes

Result

1 70 177 male nails Type 2 Candida

2 69 162 male toes Type 1 Candida

3 77 273 female vagina Type 1 Candida


5 77 277 male nails Type 1 -


7 73 226 female vagina Type 1 -


9 69 173 male toes Type 1 -



12 69 169 female toes Type 1 Candida






26


Table 5. (Cont.)









16 60 218 female toes Type 1 -













93 62 263 Female nails Type 2 Candida

39 42 183 Female vagina Type 2 Candida













27


Table 5. (Cont.)






72 45 334 female toes Type 1 -



62 56 373 female vagina Type2 Candida





66 73 100 male nails Type2 Candida

67 42 150 female vagina Type2 Candida







73 62 552 male Fingers Type 2 Candida














28


Table 5. (Cont.).


















(-) Absence of Candida infection

Conclusion

High prevalence of Candida albicans was observed in this study. This investigation has

shown that factors such age of the patients with diabetes responsible for prevalence of

Candida. Our finding should be taken into consideration in further studies regarding

presence of Candida among diabetic patients. Moreover, it is important for diabetic

patients to maintain good control of level of glucose in blood and maintenance of adequate

hygiene of body which are critical in the prevention of Candida infection.

References

Abourghiba, T. and Alghdeum, Z. (2020). Prevalence of Vaginal Candidiasis among

Diabetic and Non-Diabetic Pregnant Women in Three Hospitals in Tripoli-Libya.

Libyan Journal of Science, 23,115-119.

Barnett, J. A. (2004). A history of research on yeasts 8: taxonomy. Yeast, 21(14), 1141-

1193.

Brown, A. J., Odds, F. C., and Gow, N. A. (2007). Infection-related gene expression in

Candida albicans. Current opinion in microbiology, 10(4), 307-313.

29


Chaffin, W. L., Lopez-Ribot, J. L., Casanova, M., Gozalbo, D. and Martinez, J. P. (1998).

Cell Wall and Secreted Proteins of Candida albicans: Identification, Function and

Expression. Microbiol. Mol. Biol. Rev., 62, 130-180.

Faidah,. H. S. (2013). Vulvovaginal Candidiasis among Women in Makhah City, Saudi

Arabia. Research. Journal of Medical Science, 7(4), 86-89, ISSN:1815-9346.

Eggimann, P., Garbino, J., & Pittet, D. (2003). Epidemiology of Candida species

infections in critically ill non-immunosuppressed patients. The Lancet infectious

diseases, 3(11), 685-702.

Hedayati, T. and Shafiei ,G. (2010). Candidiasis. emedicine Specialties.

Kabir, M. A., Hussain, M. A. and Ahmad, Z. (2012). Candida albicans: a model organism

for studying fungal pathogens. International Scholarly Research Notices, 2012.

Maleeha, S., Rubeenahafeez, S. and Tahir, M. (2008). Vulvovaginal candidiasis in

pregnancy. Biomedica, 24, 54-56.

Malazy, O. T., Shariati, M., Heshmat, R., Majlesi, F., Alimohammadian, M., Moreira, D.

and Paula, C. (2006). Vulvovaginal candidiasis. Inter. J. Obstet., 92, 266-267.

Morad, H. O. J., Wild, A.-M., Wiehr, S., Davies, G., Maurer, A., Pichler, B. J. and

Thornton, C. R. (2018). Pre-clinical Imaging of Invasive Candidiasis Using

Immune PET/MR. Front. Microbiology 9, 1996.

Muvunyi, C. M. and Hernandez, T. C. (2009). Prevalence of Bacterial vaginitis in women

with vaginal symptoms in South Province, Rwanda. African Journal of Clinical

and Experimental Microbiology, 10(3).

Nelson, M ., Manjiru, W. and Margaret, M. W. (2013). Identification and susceptibility

profile of vaginal Candida species to antifungal agents among pregnant women

attending the antenatal clinic of Thika District Hospital, Kenya. J. Med.

Microbiol., 3, 239–247.

Sudbery, P., Gow, N. and Berman, J. (2004). The distinct morphogenic states of Candida

albicans. Trends in Microbiology, 12(7):317-24

Tapper-Jones, L. M., Aldred, M. J. and Walker, D. M. (1981). Candida infections and

populations of Candida albicans in mouths of diabetics. Clin. Pathol., 34(7), 706-

11.

Willinger, B. and Manafi, M. (1999). Evaluation of CHROM agar Candida for rapid

screening of clinical specimens for Candida species. Mycoses, 42, 61–65.

Zisova, L. G., Chokoeva, A. A., Amaliev, G. I., Petleshkova, P. V., Miteva-

Katrandzhieva, Y. M., Krasteva, M. B., Uchikova, H. E. Kouz-Manov, A. H. and

Ivanova, Z. V. (2016). Vulvovaginal Candidiasis in Pregnant Women and its

Importance for Candida Colonization of New borns. Folia Medical. 58, 108-114.

31


The Effect of Mechanical Scarification on Seed Germination of

Helianthemum lippii (L.) Dum. Cours.

Saleh Isslugi2 and Ali A. Elagael1

2Department of Botany, Faculty of Science, University of Tripoli 1Department of plant protection, Faculty of Agriculture, University of Tripoli

Abstract

Improving germination of Helianthemum lippii is important for conservation efforts

regarding the regeneration of the desert flora and for truffle cultivation. As with other

members of Cistaceae, the species is characterized by hard-coated seeds that causes long seed

dormancy. In this experiment, the effect of mechanical scarification of seeds using sandpaper,

shaker or household mixer on seed germination of Helianthemum lippii was investigated.

The results showed that manual rubbing of seeds of H. lippii between two pieces of sandpaper

grid size 400µm 4, 8, 16, or 32 times enhanced germination rates from 19% for the control

to 92-99%. Using a Shaker for 5, 10 or 15 minutes improved the germination rates upto 74-

79%. Significant differences between the control and the treated seeds appeared very early

and lasted throughout the experiment. The number of rubbing times or the time of exposure

of the seeds to shaker had no significant effect. Using a household mixer for 1, 2, or 4 minutes

increased the germination rates to 41, 99 and 90% respectively. However, stretching the time

of exposure to 6 minutes gave nil germination. Mechanical scarification using sandpaper,

mixer or shaker was found very effective for seed germination in H. lippii, but the first

method was especially practical and easy to apply.

Key words: Germination; Scarification; Helianthemum lippii; Cistaceae.

صلخستالم يكتسب أهمية خاصة في إنجاح عمليات الحماية وإعادة تعمير .Helianthemum lippii Lزيادة معدلات إنبات نبات

ما هو الحال مع كالغطاء النباتي الصحراوي, بالإضافة إلى أهمية إكثاره بحثيا كعائل للكماء باعتبار علاقتهما التكافلية.

.بذورال يتميز هذا النوع بصلابة القشرة التي تسبب سكون Cistaceaeلعائلة التابعة الأنواع باقي

ورق هي أليات ثلاث وذلك باستعمال إنباتها معدلات علىH. lippii نبات بذور خدش تأثير دراسة تم التجربة هذه في

البذور فرك أن النتائج أظهرت (Household mixer). المنزلي والخلاط (Shaker) , هزاز (Sandpaper) الصقل

بنسبة مقارنة %33-31 إلى الإنبات نسبة تحسين إلى أدى مرة 91 أو 26, 2, 3 ايدوي 400µmحجم صقل ورقتي بين

معنوية فروق ظهرت. %73-73 إلى الإنبات رفع نسبة أيضا دقيقة 27 أو 29, 7 لمدة الهزاز استعمال. الشاهد في 23%

لم هزلل تعرضها زمن أو البذور فرك مرات عدد. نهايتها إلى واستمرت التجربة بداية منذ والشاهد المعاملة البذور بين

على %39و 33, 32 إلى الإنبات نسبة دقائق زاد 3 أو 1, 2 لمدة المنزلي الخلاط استعمال. معنوي لهما تأثير يكن

في جدا فعال كان الثلاث الخدش اليات استعمال. نهائيا الإنبات عدم الى ادى دقائق 6 لمدة استعماله تمديد لكن التوالي,

.التطبيق وسهلة عملية بكونها الصقل تمتاز ورق بواسطة الفرك طريقة لكنو H. lippii بذور انبات معدلات زيادة

Accepted for Publication: 2/5/2021

32


Introduction

Helianthemum lippii (L.) Dum. Cours. is a perennial plant adapted to the semi-arid

climate dominatant in many vulnerable ecosystems world wide including North Africa

and Mediterranean regions (Escudero et al., 2007). Zaman et al., (2019) reported that “H.

lippii is confined to extreme desert climate where the mean annual rainfall is less than 70

mm". Besides the advantages of this species adaptation to these extreme conditions, the

literature referred to the economical, ecological, medicinal and pastoral importance of H.

lippii and to its pivotal role in the struggle against desertification and the stabilization of

vulnerable sites (Hamza et al., 2013).

Seed germination is a critical step in the life cycle of Cistaceae members as their seed

coats are impermeable to water and gas exchange (Thanos et al., 1992). Fenner (1985)

and Thompson (1992) considered seed hardness as advantageous for maintaining a

persistent soil seed bank, a characteristic that is highly appropriate for the viability of

plant populations, especially in regions with unpredictable climate such as precipitation.

Cerabolini et al., (2003) and Probert et al., (2009) added that seed dormancy of the

Cistaceae family, allows them to be stored under laboratory conditions for long periods

(more than five years, in some cases more than twenty years) without any loss of viability.

In nature, hard-coated seed plants utilize different mechanisms to erode seed coat and

to break the dormancy of their seeds (Baskin and Baskin, 2014). Among these

mechanisms are thermal shock produced during fires, alternating moisture (by dew, mist

or rain) and drought and/or major soil temperature changes (Tebar et al., 1997). Also,

fungal attack and rainfall wash (Robles and Castro, 2002). Another mechanism is the

natural scarification is abrasion of seed coat by soil particles or by herbivores ingestion.

Robles and Castro (2002) found that incubation of H. apenninum seeds in sheep rumen

enhanced their germination from 12% to 32%. Gardener et al., (1993) suggested that the

proteolytic, amylolytic and lipolytic enzymes that the ingested seeds are exposed to may

soften their seed coat and thereby increase their germination rate, a mechanism which has

been reported for some Cistaceae species (Malo and Suarez, 1996). Trabelsi et al. (2017)

investigatea the role of camel’s alimentary canal in the regeneration of the aesert flora by

germinating the seeas aispersea by camel’s faeces. They founa that out of 712 seealings

emerged from 48 faecal samples examined, 570 seedlings belonged to Cistaceae

including 316 seedlings that were H. lippii.

Abrasion of hard-coated seeds between two pieces of sandpaper, for example, softens

the seed coat and increases water permeability and gas exchange. This kind of mechanical

scarification was found to break dormancy and increase the rate of seed germination

dramatically in many species of the genus Helianthemum like: H. almeriense, H.

appeninum, H. cinereum, H. hirtum and H. squamatum (Perez-Garcia and Gonzalez-

Benito, 2006). Also H. kahiricum (Hamza and Neffati, 2015), H. salicifolium (Yeşilyurt

et al., 2017) and H. lippii (Zaman et al., 2019). Because of seed dormancy, germination

of H. lippii is very low without treatment. Investigating germination requirements of this

species could be used for conservation practices as well as to understand and develop

33

The Effect of Mechanical Scarification on Seed Germination of Helianthemum lippii

their symbiotic relationship with truffle (Jamaila and Banihashemi, 2012; Bradai et al.,

2014).

Materials and methods

Plant materials: Ripe fruits (capsules) containing mature seeds were handpicked from

wild H. lippii population located in the Faculty of Agriculture Farm, University of Tripoli,

Libya during June 2018. They were then stored in a closed glass container under lab

conditions for a few months. Seeds were cleaned by removing capsule remains. The seeds

were then treated as follows:

1- Control: Intact seeds receiving no treatment (1 lot).

2- Scarification using sandpaper: Intact seeds were manually scarified by gentle rubbing

between two pieces of sandpaper grid size of 400 µm for 4, 8, 16 or 32 times (4 lots).

3- Scarification using household mixer: Intact seeds were placed in the container of a

regular household mixer (Atlas) model MJ-2071 volume 1.5 liter. The container was then

half-filled with distilled water. The mixer was then run on medium speed for 1, 2, 4 or 6

minutes. After that, the water was filtered with filter paper to separate the seeds (4 lots).

4- Scarification using shaker: Intact seeds were placed in a 1000 ml beaker containing 5

pieces of gravel size no. 4. The beaker was then half-filled with distilled water and shaked

using a shaker (Flac) at the speed of 140 R.P.M. for 5, 10 or 15 minutes. The water was

then filtered with filter paper to separate the seeds (3 lots).

Each of the last 12 treatments (lots) was represented by four replicates (Petri dishes)

with 25 seeds each. Germination experiments were conducted in 9cm diameter disposable

Petri dishes lined with Whatman filter paper moistened with distilled water. All Petri

dishes were then placed in the dark (Zaman et al., 2019) in an incubator at a constant

temperature of 20±0.5°C, (Thanos et al., 1992). The Petri dishes were moistened regularly

as needed. Seeds showing radicle emergence were recorded daily and removed from the

Petri dishes. The final germination was recorded after 20 days from the start of the

experiement.

Differences in germination rates among treatments were subjected to one-way analysis

of variance (ANOVA) and Tukey honestly significant differences post-hoc test.

Results

Fig.1 shows that the mechanical scarification using sandpaper increased the

germination rate in Helianthemum lippii significantly (P<0.01) regardless of the number

of rubbing times. Germination rates increased from 19% for the control to 92, 97, 97 and

99% for seeds rubbed 04, 08, 16 and 32 times respectively. Since the first day, significant

differences in germination rates appeared between the control and the seeds scarified by

sandpaper for 16 or 32 times. After that and throughout the experiment, the differences

between the control and any lot of the scarified seeds were significant (P<0.01). The

differences among the scarified seeds were not significant.

34


Fig. 1. The effect of mechanical scarification using sandpaper on seed germination of

Helianthemum lippii.

*For any particular day, figures denoted by different letters are significantly different at

(P<0.01).

Fig.1 reveals that mechanical scarification using sandpaper also reduced the time to

reach the maximum germination rate, Which was reached on day 12 in the control

compared to days 6, 3, 3 and 3 in seeds rubbed 04, 08, 16 and 32 times respectively.

Mechanical scarification using the shaker increased the germination rate of H. lippii

significantly (P<0.01) regardless of the time of exposure. Germination rates increased

from 19% for the control to 74, 79 and 75% for seeds scarified by shaker for 05, 10 or 15

minutes respectively. Shaker scarification also shortened the time needed to reach the

maximum rate of germination which was shorter in the seeds shaken for 15, 10 and 5 days

respectively. During the first five days after treatment, the rate of germination was higher

in the lots of seeds that were shaken 15, 10 and 05 minutes respectively even though the

differences between treatments were not significant (Fig. 2).

Mechanical scarification using a regular household mixer had a significant effect

(P<0.05) on seed germination of H. lippii (Fig. 3). There was an interaction between the

effect and time of exposure to the mixer scarification.

0

10

20

30

40

50

60

70

80

90

100

2019181716151413121110987654321

Ge

rmin

ate

d s

ee

ds

%

Days after the begining of the experimentControl 4 Times 8 Times 16 Times 32 Times

a

6

b

b

a a

b

a

b b b

a a

b b b b

35


Fig. 2. The effect of mechanical scarification using shaker on seed germination of

Helianthemum lippii.

* For any particular day, figures denoted by different letters are significantly different at

p<0.01.

The rate of germination in the control seeds was 19%, whereas the germination rate for

seeds treated with a household mixer for one minute was 41%, two minutes was 99%,

four minutes was 90% while, six minutes produced nil germination. Fig. 3 also shows

that mechanical scarification using a regular household mixer also reduced the time

needed for the seeds to reach the maximum rate of germination which was 7, 6, and 5

days for seeds scarified with mixer for 1, 2 and 4 minutes.

Discussion

Cistaceae is characterized by hard-coated seeds. This is regarded as advantageous for

plants living in inconsistent climatic zones. It also secures the germination of seeds in the

right circumstances. Baskin and Baskin (2014), stated that dormancy is widespread

among desert shrubs, with only a few species having non-dormant seeds. Evolutionary,

these plants utilize variable mechanisms to erode their seed coats and overcome seed

dormancy. Mechanical scarification is a way to mimic some of these natural processes.

In this experiment 3 ways of seed mechanical scarification were investigated; manual

sandpaper, shaker and house hold mixer. They all enhanced the germination of H. lippii

significantly. Also, shortened the time needed for the treated seeds to reach their

maximum rate of germination. The results of this experiment show that the maximum

0

10

20

30

40

50

60

70

80

90

100

2019181716151413121110987654321

Ge

rmin

ate

d s

ee

ds

%

Days after the begining of experimentControl 0 5 Min 10 min 15 Min

a

a a a

b b b b

a a a a

36


seed germination of the control was 19%. Mechanical scarification improved the

germination percentage in scarified seeds significantly. The percentages were 92-99%

using sandpaper, 41-99% using mixer and 74-79% using shaker. The differences between

the control and the scarified seeds appeared very early and were significant throughout

the experiment. Very similar results are found in the literature which support the strong

positive impact (reaching values approaching 100%) of manual sandpaper scarification

on seed germination of Helianthemum lippii (Zaman et al., 2019) as well as other species

in the same genus such as; H. squamatum (Escuedero et al. 1997), H. apenninum (Robles

and Castro, 2002) and H. kahiricum (Hamza and Neffati, 2015). Time of exposure of the

seeds to treatments was a limiting factor when mixer was used as a tool for seed

scarification. The germination rates achieved using the mixer for 1, 2 and 4 minutes were

41, 99 and 90%. However, subjecting the seeds to 6 minutes of mixing damaged the seeds

and killed their embryos resulting in nil germination. Another disadvantage of using a

mixer or shaker as tools for scarification of seeds is that the seeds are very small and must

be submerged in water which makes their separation from the water time consuming as

compared to sandpaper method.

Fig. 3. The effect of mechanical scarification using regular house hold mixer on seed

germination of Helianthemum lippii.

* For any particular day, figures denoted by different letters are significantly different at

p<0.05.

0

10

20

30

40

50

60

70

80

90

100

2019181716151413121110987654321

Ge

rmin

ate

d s

ee

ds

%

Days after the begining of the experimentControl 1 mim 2 min 4 Min 6 Min

a

a

a a a a

b

b b b b

c C

c c

d d d d

37


Conclusion

Helianthemum lippii is characterized by having hard coated seeds impermeable to water

and gas exchange which causes long seed dormancy. The seeds have a potentially high

rate of germination (≥90%) if the coats are eroaea by some mechanism. This experiment

supports the findings of others that mechanical scarification is very effective, particularly

the use of manual sandpaper scarification. It is extremely effective and practical.

References

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longevity: a comparative study on 195 species. Ann. Bot., Oxford, 104,57–69.

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Robles, A. and Castro J. (2002). Effect of thermal shock and ruminal incubation on seed

germination in Helianthemum apenninum (L.) Mill. (Cistacea). Acta Botanica

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(Balearic islands, Spain). Acta Botanica, 22, 53-63.

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Download date 21/08/2019.

39


Biology and Growth Performance for Fry Red Tilapia Feed

With Spirulina

Entisar Mohamed Eljaziri1 and HishamAddin Bin Omar

University Putra Malysia, Faculty of Agriculture, Department of Aquaculture. [email protected]

Abstract

The use of fish feed with nutrient deficiency is common in present aquaculture practice and

it causes the highest fish mortality and economic loss in this industry. Microalgae

(Spirulina) is known to have good nutritional and chemical compositions that are good for

fish feed. An experimental study was carried out to determine the nutritional composition

of Spirulina, the biology and growth performance of red tilapia when feed with different

ratio of Spirulina. Twelve cages sizes 1x1x0.9m and built with netlon and polyvinyl

chloride were used and arranged in concrete tanks to culture the fish. The fish feed was

prepared with own grown spirulina. The fish was fed with different ratios (0%, 1%, 3%,

5%, and 7%) of Spirulina for 13 weeks. The results show that locally grown Spirulina are

far better than those from other countries in performance. The 3% Spirulinar ration gave

the best fish weight growth, total length, fish appearance and gonad weight. Thus, the

locally grown Spirulina fish feed was found to be good for supplementation in fish feed

with 3% given the overall growth performance to red tilapia and it is considered to be a

potential candidate to replace the fish meal and feed formulation.

Keywords: Red Tilapia; Spirulina feed; Aquaculture; Experimental study.

المستخلصيسبب أعلى هو الحالية و ةالمائي الزراعةيعد استخدام أعلاف الأسماك التي تعاني من نقص المغذيات أمرا شائعا في ممارسة

)سبيرولينا( لديها تركيبة غذائية الدقيقة قتصادية في هذه الصناعة. من المعروف أن الطحالبالاخسارة للمعدل وفيات للأسماك و

البلطي على مو الن تطورو حياتهاوكيميائية جيدة لتغذية الأسماك. أجريت دراسة تجريبية لتحديد التركيبة الغذائية للسبيرولينا و

نيتلون وكلوريد منبنيت متر x 1 x 0.9 4بحجم قفص 49بنسب مختلفة من سبيرولينا. تم استخدام يتهالأحمر عند تغذ

البوليفينيل في خزانات خرسانية لتربية الأسماك. تم إعداد أعلاف الأسماك باستخدام سبيرولينا. تم تغذية الأسماك بنسب مختلفة

مناسبة في أسبوعا. أظهرت النتائج أن سبيرولينا المزروعة محليا 46( من سبيرولينا لمدة ٪ 3، و ٪ 5، ٪ 6، ٪ 4، ٪ 0)

وزن الغدد ومظهر الأسماك ونشاطها والكلي هاطولوأفضل نمو لوزن الأسماك ، ٪6بيرولينا الأداء. أعطت نسبة سجودة

لارتفاع نظرا ٪ 6أعلاف سمكة سبيرولينا المزروعة محليا جيدة لإضافتها في أعلاف الأسماك بنسبة بناء عليه فإنوالتناسلية

تها.صياغفي حل محل وجبة الأسماك ومرشحا محتملا لت هي لذلك تعدداء النمو الكلي للبلطي الأحمر وأ


41


Introduction

Tilapia is among three genera species of economic importance.It has been cultured for

the last 2,500 years (Chapman, 2000). There has been a steady increase in the global

production of tilapia during the period 1991 to 2002, with annual production of 1.5

million tones per year when the global fish production was almost 51.4 million tons

(Ramnarine, 2005).

Nutrition for fishmeal in aquaculture promotes optimal fish growth and health. When

fish are cultured in a system without natural foods, for example, trout raceways, or when

the contribution of natural foods is only marginal with regard to nutrition, like intensively

stocked catfish ponds, there is a need for the feed to be nutritionally adequate (Lovell,

1989). Fishmeal is currently the main source of protein utilized to feed the fish. However,

because of the expansion of aquaculture systems based on the use of fishmeal as a major

ingredient for aqua feeds, the meal is becoming unsustainable. As such, many studies

have focused on the search for alternative protein sources suitable for use in aqua feeds,

which might reduce the dependency on fishmeal. Alternative protein source that meets

some important requirements, such as high protein content, adequate fatty acid profiles,

secured supplies, as well as affordable costs are, thus, investigated (Nagel et al., 2012).

Plant protein meals such as soybean meal, rapeseed meal, corn gluten meal or wheat

gluten have been used successfully as ingredients for fish feeds (Cabral et al., 2011, Nagel

et al., 2012 and Santigosa et al., 2008; Silva et al., 2010, Cruz-Suárez et al.,

2009, and Tibaldi et al., 2006). However, plant protein sources contain a wide range of

anti-nutritional factors, and hence, high inclusion level of these ingredients can induce

negative effects on growth and on digestive enzyme activities (Santigosa et al., 2008).

Therefore, protein sources of plant origin do not represent an ultimate alternative to

fishmeal, and hence, the need to find new aqua feed ingredients remains currently a

challenging goal. Accordingly, microalgae appear as a promising alternative to enhance

the nutritive value of conventional feeds, and to be used, at least partially, as a substitute

for fishmeal (Lupatsch, 2009). Microalgae consist of high levels of beneficial

carbohydrates, proteins, lipids and antioxidants making them an essential food source in

the rearing of all stages of marine bivalve molluscs (clams, oysters, scallops), the larval

stages of some marine gastropods (abalone, conch), larvae of several marine fish species,

penaeid shrimp and zooplankton (Muller-Feuga et al., 2000). It is also capable of

producing omega-3 and omega-6 (long-chain) poly-unsaturated fatty acids known to be

required in human nutrition. Partial substitution of fishmeal by microalgae biomass can

induce positive effects on growth, feed utilization, lipid metabolism, body composition,

meat quality, and resistance to stress and diseases. This study deals with the biology and growth performance in Fry Tilapia feed with

Spirulina. In order to achieve this goal, the study will focus ondetermining the nutritional

composition of Spirulina grown in fish tank and, 2) Determination of fish growth fed with

different ration of Spirulina 1%, 3%,5% and 7% in terms of length and weight, growth

rate and FCR.

41

Biology and Growth Performance for Fry Red Tilapia


A total of twelve cages were used and arranged in a concrete tank with dimensions of

4.7m x 4.2m at the hatchery, TPU, UP Malasysia. The cages were built of netlon and

polyvinyl chloride (PVC) supplied commercially. Each cage was 1m x 1m and 0.9m deep.

The concrete tanks were equipped with a complete aeration system (Fig. 1).

Fig. 1. Layout of the cages (left) and phot of cages built with netlon and PVC (right).

The red tilapia fingerlings used were obtained from a local farmer (SA Agromax

Enterprise, Puchong). They were subjected to an acclimatization period of 2 weeks (Li et

al., 2015) and fed with control diet free of spirulina. Fingerlings with an average weight

of 1.23g and 4.0cm length, were randomly selected and placed into the cages with

capacity of 24 fish per cage and total of 72 fish per trearment. Groundwater was used in

the system and 1/3 of the water volume in the concrete tank was replaced once every two

weeks in order to offset evaporation loss. The tank was cleaned once a month.

The fish feed was prepared by addition of commercial Spirulina with a ground

commercial fish feed obtained locally. It conisits of home-grown dried Spirulina powder.

Feed formulation was determined according to the feeding rations of 0%, 1%, 3% and

5%. The fish sample were fed twice a day (at 10.00 a.m. and 05.00 p.m.) till adlibtum for

90 days using feeding trays that were prepared to assist in fish feeding (Table 1).

The proximate analyses of the Spirulina, commercial fish feed, and a mixture of

Spirulina with fish feed were done according to the AOAC method at the Faculty of

Agriculture, University Putra Malysia. They were all measured based on the composition

of crude protein (Kjedahl protein), crude lipid, crude fiber, ash and moisture.

Water quality monitoring was done once every two weeks based on five different

parameters; ammonia-nitrogen, nitrate, dissolved oxygen (DO), pH and water

42


temperature. The water temperature, DO and pH readings were observed in the morning

hours using the multi-probe before fish sampling. For moisture content was measured

according AOAC; section930.15 recommendations and Ash was determined by standard

procedures outlined in the AOAC procedures section 942.05.

Following the method of Kjedhal (1833) described by the AOAC in section 954.05

crude protein is analyzed. 10ml of H2SO4 acid and a tablet of Kjeldahl catalyst were added

into the digestion tube. The latter is inserted into a digester and heated to 720oC for one

hour afterwhich the temperature is increased to 420oC for another hour. The tube was then

allowed to cool for 4 hours and crude protein was analysed using protein analysing

machine (Kjaltex). The result was automatically calculated by the instrument in

percentage.

Feed crude fat was determined using the AOAC method suggested in section 920.39.

Three grams of feed sample were weighed and transferred into the extraction thimble.

The mouth of thimble was covered with coton wool and then inserted into Soxhlet

apparatus. The aluminum cap was weighed and 200ml of petroleum ether added. The

Soxhlet apparatus is fixed to the aluminum cap and attached to the condenser. Gentle

water flow was started through the apparatus which was then heated gradually at 60oC

until finish. After heating the aluminum cap was detached and the solvent was drained

from the Soxhlet apparatus and the aluminum cap was placed in the oven to dry at 100oC

for 30 minutes. After draining it was taken out and cooled in the dessicator before being

weighed, recorded and fat content calculated.

Results and Discussion

Commercial Fish Feed Immediate analysis has been done to determine the nutritional composition of

commercial fat for fish feed used. The chemical properties content in the feed consist of

12.5% moisture, 6.8% ash, 27.9% crud protein, 8.9% crude lipid and 5.4% crude fiber.

The content was compatible with the composition stated on the commercial fish feeds'

package.

The nutritional condition stimulates the fish immune system (Oliva-Teles, 2012).

Protein is an essential for amino acids which is the important defense mechanism in the

fish body (Li et al., 2007). In this study crude protein in the supplied feed was ca. 63% as

apposed to the initial commercial percentage of ca. 28%. This is consistent with

Tokusoghu and Unal (2003) who reported the use of protein content of spirulina ca. 60 to

64% on different types of fish. The carbohydrate and lipid play an important role in

optimizing the efficiency of protein utilization by protein sparing effect (Johnston et al.,

2003).

Nutritional Composition of Feed Different ratios of spirulina, ranging from 1% to 7% were added to the fish feed. A

proximate analysis result shows that the properties increase with increasing ratio except

43


for ash which decreases and crude fiber as well as crude lipid in some cases. The 7%

formulated ratio of spirulina shows highest protein with 29.98 and moisture 13.01% as

well as crude lipid 8.98 while lowest in ash with 4.24 compared to 0%, 1%, 3% and 5%.

For crude fiber, 0% has the highest with 5.40 compare to others.

The formulation of fish feed with 1%, 3%, 5% and 7% ratios of spirulina used was

done to observe their effect towards the red tilapia growth and survival. This protocol was

conducted with different ratio of spirulina species (e.g. Vasudevan et al.,2006; Teimouri

et al., 2013; Nakagawa and GomezDiaz, 1995 and Ramakrishnan et al., 2008). All the

studies yielded positive results when compared with feed with absence of spirulina.

Effect of Spirulina Ratios on Fish Growth Weight Result of different ratios of spirulina feed for red tilapia show positive increase in the

fish mean weight across the weeks at different ratios with 3% and 1% ratios showing

higher growth weight (Table 1). A remarkable increase in the mean weight was noticed

in week 6 and week 8 at all the ratios. This may be due to the adaptability to the feed

nutritional content while at week 10 and 13 the rate exhibits decline, which may be due

to fish metabolism and water quality decline. One-way ANOVA test between group

analyses, showed no significant difference between the spirulina ratios at P> 0.05 level

with [F(4,100) = 1.436, P = .228].

Table 1. Mean of Red Tilapia Growth Weight (g)

Spirulina

concentration

Weight (g)

week 2

Weight (g)

week 4*

Weight (g)

week 6

Weight(g)

week 8

Weight(g)

week 10

Weight(g)

week 13*

Control 2.6±0.82ab 4.9±0.45b 8.7±0.60c 17.2±1.87d 18.4±1.35d 27.0±1.17e

1% 2.99±0.35ab 5.8±0.28b 10.6±0.51c 18.6±1.17d 23.7±1.89e 36.4±1.14.f

3% 2.8±0.68ab 5.6±0.70b 12.0±0.60c 22.6±1.74d 33.2±1.08e 40.6±1.45f

5% 3.1±0.88ab 5.8±0.49b 11.6±0.20c 27.4±1.48d 35.6±1.02f 30.00±1.64

e

7% 2.9±0.80ab 5.5±0.84b 13.0±0.09c 30.6±1.31d 37.6±1.73f 25.5±1.12e

*Note: Means within rows with different superscripts are significantly different.

The fish growth weight displays an increase in the first phase of the experiment (week 2

and 4) from 2.6g to 5.8g were 0% spirulina increases from 2.6g at the first two weeks (15

days) to 4.9g at 4th week (29 days) while 1% and 5% increased from 2.99g to 5.8g and

3.1g to 5.8g (Fig. 1a). However, high increase in fish growth weight was noticed in the

second phase of the experiment with 7% having the highest increase from 13.0g at week

6 to 30.6g at week 8 compared to the control (0%) with increase from 8.7g at the week 6

to 17.2g at the week 8 (Fig. 1b).

The third phase of the experiment exhibited slow growth pattern (week 10 to 13) with

decline in some cases. A high decline was observed at 7% from 37.6g at week 10 to 25.5g

at week 13 and slow increase in growth was observed in 3% f rom 33.2g at week 10 to

44


40.6g at week 13 (Fig. 2), nevertheless, cumulatively it has the highest performance. This

may be due to the excess utilization of spirulina dietary which was reported to cause

negative impact on fish growth in striped jack, Pseudocaranxdentex and red tail prawn,

Penaeuspenicillatus (Nakagawa and Gomez-Diaz,1995). The results are consistent with

feed with high ration of spirulina in high fish (Vasudevan et al., 2006) and in juvenile

common crap (Ramakrishman et al., 2008). ANOVA test showed significant difference

in fish weight (at P< 0.05 level) between different ratios across the three phases of the

experiment with [F(9,20) = 55400.000, P = .000] for phase one (week 2 to 4), [F(9,20) =

1688536.667, P = .000] for phase two (week 6 to 8), [F(14,30) = 1716748.571, P = .000]

for phase three (week 10 to 13).

Fig. 1. Fish growth weight at (a) phase one (week 1 to 4) and (b)phase two (week 4 to

8).

Fig.2 Fish growth weight at the phase three (week 10, 12 & 13).

Table 2 illustrates the ANOVA result. This was further supportrd by Turkey HSD

post-hock test which was performed to identify where the differences occur. The result

45


shows a significant difference between all the ratios across the weeks in all the three

phases of the experiment except in some cases.

Table 2. ANOVA test of week`s weight on different ratio of spirulina.

Variables N Mean SD df F P

Phase 1 (weeks 2&4) 9 55400.000 .000

Week 2 0% 3 2.60 .01 20

Week 4 0% 3 4.90 .01

Week 2 1% 3 4.00 .01

Week 4 1% 3 5.80 .01

Week 2 3% 3 2.80 .01

Week 4 3% 3 5.60 .01

Week 2 5% 3 3.10 .01

Week 4 5% 3 5.80 .01

Week 2 7% 3 2.90 .01

Week 4 7% 3 5.50 .01

Phase 2 (weeks 6 & 8) 9 1688536.667 .000

Week 2 0% 3 8.70 .01 20

Week 4 0% 3 17.20 .01

Week 2 1% 3 10.60 .01

Week 4 1% 3 18.60 .01

Week 2 3% 3 12.00 .01

Week 4 3% 3 22.60 .01

Week 2 5% 3 11.60 .01

Week 4 5% 3 27.40 .01

Week 2 7% 3 13.00 .01

Week 4 7% 3 30.60 .01

Phase3(weeks10&13) 14 1716748.571 .000

Week 2 0% 3 18.40 .01 30

Week 4 0% 3 27.00 .01

Week 2 1% 3 23.70 .01

Week 4 1% 3 36.40 .01

Week 2 3% 3 33.20 .01

Week 4 3% 3 40.60 .01

Week 2 5% 3 35.60 .01

Week 4 5% 3 30.00 .01

Week 2 7% 3 37.60 .01

Week 4 7% 3 25.50 .01

Effect of Spirulina ratios on Fish Growth Length

Fish growth length (Table 3) shows positive increase in the fish mean length for all

spirulina ratios across the weeks. The 3% ratio, however, have the highest growth length

of 12.9cm. A remarkable increase was noticed in weeks 6 and 8 at all ratios, as it increases

from the mean average of 6cm in week 4 to 8cm in week 6. This may be due to the

adaptability to the feed nutritional content. While at weeks 10 and 13 the increase pattern

returns back to its previous trend which may also be due to the fish metabolism and/or

46


water quality decline. One way ANOVA analysis shows no significant difference in fish

weigh between the spirulina ratios at P> 0.05 level with [F(4,100) = .303, P = .875].

Table 3. Mean of Red Tilapia Growth Length (cm).

Spirulina

concentration

Length (cm)

week 2

Length(cm)

week 4*

Length(cm)

week 6

Length(cm)

week 8

Length(cm)

week 10

Length(cm)

week 13

Control 5±0.67b 6.1±0.71c 7.6±0.11d 9.5±0.16e 11.4±0.54e 11.6±0.99f

1% 5.2±0.58b 6.5±0.89c 8.1±0.96d 9.8±0.10e 10.8±0.24f 12.7±0.11g

3% 5.1±0.57b 6.5±0.71c 8.6±0.58d 10.2±0.79e 11.5±0.79f 12.9±0.80g

5% 4.9±0.46b 6.5±0.64c 8.4±0.89d 10.9±0.4e 11.6±0.49f 12.5±0.88g

7% 5.2±0.48b 6.5±0.75c 8.8±0.92d 11.1±0.79e 11.8±0.83f 11.8±0.57g

*Note: Means within rows with different superscripts are significantly different

At the first phase of the experiment (week 2 and 4) the length growth pattern was slow

with 3% having the highest 5.1cm at week 2 (15 days) compared to other ratios. At week

4, however, the growth pattern becomes uniform at 6.5cm except for 0%; 6.1cm (Fig.3a).

The growth length increasing pattern changed in the second phase weeks 6 and 8 with

high relative increase. The 7% ratio shows the highest increase from 8.8cm at week 6 to

11.1cm at week 8 while 0% have the lowest increase from 7.6cm at week 6 to 9.5cm at

week 8 (Fig. 3b).

Fig. 3. Fish length at (a) phase one (week 1 to 4) and (b) phase two (week 4 to 8).

The growth pattern in third phase (week 10 to 13) was back to initial pattern of the

first phase. (Fig. 4). The decline in the growth pattern may be due to the excess utilization

of spirulina dietary. A case reported by Nakagawa and Gomez-Diaz (1995) in striped

jack, Pseudocaranxdentex and red tail prawn, Penaeuspenicillatus.

Similar results in cultures fed with high rations of spirulina were reported by

Vasudevan et al. (2006) and Ramakrishman et al. (2008). A one way ANOVA (Table 4)

imbetween group analysis shows significant difference in fish length (at P< 0.05 level)

between different ratios across the three phases of the experiment with [F(9,20) =

15616.667, P = .000] for phase one (week 2 to 4), [F(9,20) = 42600. 000, P = .000] for

47


phase two (week 6 to 8), [F(14,30) = 53.559, P = .000] for phase three (week 10 to 13).

Fig. 4 Fish growth weight at the phase three (week 10, 12 &13).

The relationship between fish length and weight in different ratios of spirulina was

investigated using Pearson product-moment correlation coefficient, to ensure no violation

of the assumptions of normality and linearity. The result shows strong positive correlation

between the length and weight of all spirulina ratios with r = .987, n = 21, p< 0.005 at

1%, r .988, n = 21, p< 0.005 at 3%, r = .948, n = 21, p< 0.005 at 5% and r = .986, n = 21,

p< 0.005 at 7% (Table 5). The relationship helps to estimate the fish length and weight

biomass as well as isometric growth of the fish (Nehemia et al., 2012). This study exhibits

positive isometric growth where the fish appear to be stouter and became heavier as body

length increased.

Effect of Feed Diet Consumption on Growth Performance

Total feed consumed was calculated and 7% ratio treatment was found to consume

the highest amount of feed compared to other treatments (Table 6). This may be due to

the increase of fish appetite and consequently improvement of the growth (Aly et al.,

2008). However, it has no impact on the fish growth compared with 3% which shows

higher growth (13 weeks). Feed consumption ratio (FCR) shows the amount of feed

required to produce one unit of weight (Amoah, 2012). It also identifies the feed

performance on fish health and the cost effectiveness. At the first phase of the experiment,

1% spirulina supplement feed shows lowest FCR with 0.178g and highest feed intake of

0.809g as well as body weight gain of 4.537g compared to other treatments (Table 7). At

the second phase of the experiment treatment, with 7%, spirulina supplement shows

lowest FCR with 0.145 and highest feed intake 3.66g as well as body weight gained 2

5.1g compared with other other treatments.

48


Table 4. ANOVA test of week`s length on different ratio of spirulina. Variables N Mean SD df F P

Phase 1 (weeks 2&4) 9 15616.667 .000

Week 2 0% 3 5.00 .01 20

Week 4 0% 3 6.10 .01

Week 2 1% 3 5.20 .01

Week 4 1% 3 6.50 .01

Week 2 3% 3 5.10 .01

Week 4 3% 3 6.50 .01

Week 2 5% 3 4.90 .01

Week 4 5% 3 6.50 .01

Week 2 7% 3 5.20 .01

Week 4 7% 3 6.50 .01

Phase 2 (weeks 6 & 8) 9 42600.000 .000

Week 2 0% 3 7.60 .01 20

Week 4 0% 3 9.50 .01

Week 2 1% 3 8.10 .01

Week 4 1% 3 9.80 .01

Week 2 3% 3 8.60 .01

Week 4 3% 3 10.20 .01

Week 2 5% 3 8.40 .01

Week 4 5% 3 10.90 .01

Week 2 7% 3 8.80 .01

Week 4 7% 3 11.10 .01

Phase3(weeks10&13) 14 53.559 .000

Week 2 0% 3 11.40 .01 30

Week 4 0% 3 11.60 .01

Week 2 1% 3 10.80 .01

Week 4 1% 3 12.70 .01

Week 2 3% 3 11.50 .01

Week 4 3% 3 12.90 .01

Week 2 5% 3 11.60 .01

Week 4 5% 3 12.50 .01

Week 2 7% 3 11.80 .01

Week 4 7% 3 11.80 .01

However, at the third phase of the experiment the treatment with 7% spirulina supplement

also shows lowest FCR with -0.16 and highest feed intake of 16.1g with lowest body

weight gain of -5g compared with other treatments. This indicates the impact of higher

spirulina diet feed consumption as it may negatively affect the body weight as suggested

by Nakagawa and Gomez-Diaz (1995).

49


Table 5. Pearson product-moment correlation matrix between length and weight of spirulina ratios.

W 0% W 1% W 3% W 5% W 7% L 0% L 1% L 3% L 5% L 7%

W 0% 1

21

W 1% .987** 1

.000

21 21

W 3% .981** .988** 1

.000 .000

21 21 21

W 5% .905** .901** .948** 1

.000 .000 .000

21 21 21 21

W 7% .847** .825** .893** .986** 1

.000 .000 .000 .000

21 21 21 21 21

L 0% .963** .942** .976** .945** .918** 1

.000 .000 .000 .000 .000

21 21 21 21 21 21

L 1% .987** .982** .987** .933** .881** .977** 1

.000 .000 .000 .000 .000 .000

21 21 21 21 21 21 21

L 3% .979** .965** .981** .935** .895** .988** .996** 1

.000 .000 .000 .000 .000 .000 .000

21 21 21 21 21 21 21 21

L 5% .970** .945** .968** .954** .929** .985** .987** .993** 1

.000 .000 .000 .000 .000 .000 .000 .000

21 21 21 21 21 21 21 21 21

L 7% .940** .911** .948** .963** .953** .977** .967** .980** .994** 1

.000 .000 .000 .000 .000 .000 .000 .000 .000

21 21 21 21 21 21 21 21 21 21

**. Correlation is significant at the 0.01 level (2-tailed).

Effect of Spirulina Diet on Fish Appearance and Activity

Color score was the determinant of red tilapia appearance in the experiment. At the

end of the experimental period the fish in with 3% spirulina showed the most intense and

attractive color among the treatments with orange color when compared with fish in 0%

spirulina; the least attractive color. Teimouri et al. (2013) reported similar results. The

dietary carotenoids content in spirulina supplement feeds may be the cause of fish color

appearance as well as their skins and fins shiny (Vasudevan et al., 2006).

The activity score determined at the end of the experimental period showed also that

fish with 3% spirulina treatment are the most active, based on the struggle when handled.

51


The least active was found, as expected, in 0% spirulina. The most active isclearly

attributable to the massive weight gained by the treatment.

Table 6. Cumulative Feed Given (g) to Red Tilapia.

Week Cumulative feed given (g)

0% 1 3 5 7

1 0.062 0.062 0.062 0.062 0.062

2 0.062 0.062 0.062 0.062 0.062

3 0.312 0.36 0.336 0.372 0.348

4 0.312 0.36 0.336 0.372 0.348

5 0.49 0.70 0.67 0.70 0.66

6 0.49 0.70 0.67 0.70 0.66

7 0.78 0.95 1.08 1.04 1.17

8 0.78 0.95 1.08 1.04 1.17

9 1.55 1.67 2.03 2.47 2.75

10 1.55 1.67 2.03 2.47 2.75

11 1.7 2.1 3 3.2 3.4

12 1.7 2.1 3 3.2 3.4

13 1.8 2.608 3.152 3.424 3.8

Water Quality Effect on Culture

At the beginning of the experimental study, up to week 9, the water quality was stable.

Deterioration in the water quality was observed from week 10 to 13 (Table 8) which may

have contributed to the decline in fish growth (Amoah, 2012).

The water pH ranged 7.26 to 7.59 up to week 9, where it rises to 8.72 at week 10

though it is slightly higher than the FAO (2016) recommendation of 6.5 to 8.5 for

aquaculture. Water temperature within the weeks of 0 to 9 was within the range of 25.0

to 30.9oC. It is rises to 32.1oC at week 10, which may had affected the fish health, as it

causes greater fish metabolism (FAO, 2016). The DO in water declined towards the end

of the experiment (weeks 10 and 13). This may be due to the high temperature, fish

metabolism or fish overcrowdings. The latter may lead to increase in fish respiration

which exerts high demand for DO (FAO, 2016) and that may be the curse for poor fish

growth (Amoah, 2012). High ammonia nitrogen and nitrate were also noticed in weeks

10 and 13 that further indicates water quality deteriorationand consequently affect the fish

growth and health (FAO, 2016). Nitrate concentration in the water is attributable to

ammonia concentration as it promotes nitrification process in the water column.

Effect of Spirulina Concentration on Gonadal Development

The Gonad somatic index (GSI) which correlates to fish weight is a vital parameter in

studying the fish reproduction. A sample of five fish was taken from the experimental set-

up at each spirulina concentration. After measuring the fish weight, the gonad weight was

also taken to determine the effect of spirulina concentration on Gonadal development.

51


Table 7. Feed Conversion Rate for phase one.

Treatment Body weight gained (g) Feed intake (g) FCR

Phase 1:

0% 3.60 0.764 0.211

1% 4.537 0.809 0.178

3% 4.410 0.800 0.181

5% 4.530 0.888 0.196

7% 4.3 0.824 0.191

Phase 2:

0% 12.367 2.540 0.205

1% 12.860 3.062 0.238

3% 16.920 3.292 0.195

5% 21.630 3.233 0.149

7% 25.1 3.66 0.145

Phase 3:

0% 9.760 8.221 0.842

1% 17.726 10.233 0.577

3% 18.077 13.189 0.730

5% 2.970 14.755 4.968

7% -5 16.1 -0.16

Table 8.General water quality measurements for the experimental period.

Parameter Week 0 Week 2 Week 4 Week 6 Week 8 Week 10 Week 13

PH 7.59 7.58 7.41 7.41 7.26 8.72 7.63 Temp 30.9 29.4 28.9 29.6 25.0 32.1 31.8 DO (mg/l) 4.78 5.09 5.34 5.10 6.51 4.03 4.25

Ammonia-

Nitrogen(mg/) 0.10* 0.04** 0.03** 0.04** 0.02** 0.17*** 0.15*** Nitrate (mg/l) 1.3* 0.5** 0.3** 0.4** 0.2** 2.5*** 2.4***

*Water clear and low algae population

**Water green and high algae population

***Water cloudy and very low algae

The result shows that 3% spirulina concentration with high body weight of 40.9g has

the highest gonad weight of 0.22g and highest gonad index of 0.54 with 0% spirulina

concentration exhibiting the lowest gonad weight and index (Table 9).

52


Table 9. Mean of fish weight Gonad weight and Gonad index (± SD).

Treatment Fish weight (g) Gonad weight (g) Gonad Index (GSI)

0% 25.9± 0.77 0.09± 0.05 0.35

1% 36.1± 0.21 0.16± 0.03 0.44

3% 40.4± 0.32 0.22± 0.06 0.54

5% 29.9± 0.08 0.11±0.01 0.37

7% 25.0± 0.31 0.13± 0.03 0.52

Conclusions and Recommendations

The nutritional feed sources (spirulina) were shown to help in fish growth

performance as well as product quality. Among the different ratios of spirulina used in

the study, 3% shows remarkable performance in fish growth rate compared to the blank.

The rest of the ratios, however, also performed better but below that of 3%. The FCR

conducted shows that the feed intake with spirulina is more efficient in output compared

to commercial fish feed. Water quality seems to be very important factor in influencing

fish growth.

We therefor, concur with previous studies in recommending Spirulina supplement

feed for improving the aquaculture as it yields higher productivity due to its rich nutrients.

It is also recommended that spirulina ratios in fish feed should be carefully formulated

as excess feed utilization leads to decline in productivity. Hence a ratio between 1% to

3%, should be used in order to accomplish higher performance in all the aquaculture

management process provided that water quality is carefully monitored to avoid

deterioration.

Authors’ Resposibility

The authors substantially contributed to the conception and design of the study,

acquisition, analysis and interpretation of data. All authors are responsible for the

intellectual content of the manuscript and approved the final version of the article to be

published.

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55


السمية النباتية للزيوت العطرية الأساسية ومسحوق الأوراق لأربعة نباتات طبية Tribolium confusum Duval خنفساء الدقيق المتشابهة على البالغات ويرقات

(Coleoptera: Tenebrionidae)

7و بثينة مصطفى الصغير 7نوال عبد السلام محفوظ

كلية العلوم، جامعة طرابلس -شعبة الحشرات قسم علم الحيوان، Email: [email protected]; [email protected]

المستخلص

خسارة كبيرة تسبب Tribolium confusum Duval (Coleoptera: Tenebrionidae)الدقيق المتشابهة خنافساستخدام التقليدية؛ ويتطلب الحشرية المبيدات على وتعتمد ضعيفة لاتزال الآفة هذه ومنتجاتها. السيطرة على المحزونة للحبوب

السمية الأثار تقييم الدراسة كالمستخلصات النباتية الطبية. الغرض من هذه بدائل آمنة وفعالة عوضا عن المبيدات الاصطناعية، الريحان .Mentha rotundifolia Lحوق أوراق أربع نباتات طبية: النعناع مستدير الأوراق الأساسية العطرية ومس للزيوت

أيوكالبتوس )الكافور أو السرول( ، LSyzygium aromaticum.، القرنفل L Ocimum basilicumالحلو )الحبق( Eucalyptus globulus Labill المتشابهة يقالدق لخنافس الحشرات البالغة واليرقات اليافعة على T.

confusum معمليا. أظهرت النتائج أثر سمية الزيوت العطرية الأساسية ومسحوق أوراق النباتات الطبية على موت البالغات. بينما لم توضح 7....معنوية عند مستوى اساعة فروق 17بعد T. confusum واليرقات اليافعة لخنفساء الدقيق المتشابه

النتائج أية فروق معنوية بين حالتي النباتات من الزيوت الأساسية ومسحوق الأوراق وبين التركيزات المخففة بالكحول الإيثيلي 7.% ،7.% ،0.% (v/v). بتوس بأن والقرنفل والإيوكال النباتات الطبية من النعناع معالجاتتبين من النتائج أن مقارنة

على البالغات واليرقات اليافعة لخنفساء الدقيق 0...، 7....للريحان الحلو أثر سمي بفروق معنوية عالية عند مستوى يلي ذلك الأثر السمي للنباتات الطبية القرنفل والإيوكالبتوس على التوالي، مقارنة بأثر نبات النعناع الذي لم يضفي .المتشابهة

أنواع الزيوت بوجود xللحشرة بل كعامل منفر. كما أتضح أن تداخل المعالجة يا على البالغات واليرقات اليافعةأثرا سميا معنو الأطوار البالغة واليرقات xالأطوار البالغة واليرقات؛ المعالجة x. أما تداخل المعالجة 7....مستوى فروق معنوية عالية عند

x أثبتت النتائج قدرة سمية الزيوت العطرية ومسحوق الأوراق للنباتات 0...د مستوى حالة النباتات أظهر فروق معنوية عن .امل منفرة أو طاردة لخنفساء الدقيق المتشابهة، واستخدامها في إستراتيجيات مكافحة آفات الحبوب و الطبية المختبرة أو كع

المخزونة ومنتجاتها بطرق آمنة.

مية الس ؛مسحوق الأوراق ؛الزيوت العطرية الأساسية ؛النباتات الطبية ؛البالغات واليرقات ؛Tribolium confusumالكلمات المفتاحية: النباتية.

Accepted for Publication 20/6/2021

56

و بثينة مصطفى الصغير نوال عبد السلام محفوظ

Abstract

Flour beetles Tribolium confusum Duval (Coleoptera: Tenebrionidae) cause a major loss of

stored grains and their products. Control of this pest remains weak and relies on traditional

insecticides; it requires the use of safe and effective alternatives to synthetic insecticides such

as medicinal plant extracts. The purpose of this study is to assess the toxic effects of essential

aromatic oils and leaf powder of four medicinal plants: mint Mentha rotundifolia L., sweet

basil Ocimum basilicum L., clove Syzygium aromaticum L., eucalyptus Eucalyptus globulus

Labill on adult insects and larvae of T. confusum. Results showed toxic effect of essential

aromatic oils ana leaf powaer on aault’s aeath ana larvae of flour beetles T. confusum in a

period of 72 hours a significant difference at 0.001 level. Data indicated no significant

differences between the two plant formulas of essential aromatic oils and leaf powder, and

between three concentrations diluted with ethyl alcohol namely, 10%, 20%, 30% (v/v) mixed

with 5g flour. Sweet basil revealed a high toxic effect at 0.001, 0.05 significant difference

levels on T. confusum adults and larvae. Clove, mint and eucalyptus treatments revealed

significant difference levels on Flour beetle adults and larvae. In contrast, mint did not show

any toxic significant difference effect on T. confusum adults and larval stages. Results also

displayed an interaction of treatments x oils a high significant difference level at 0.001. The

interaction of treatment x adults and larval stages, and treatment x adults and larval stages x

plant condition showed significant difference levels at 0.05. Lab results demonstrated

phytotoxic and repellent effect of medicinal plants essential aromatic oils and leaf powders

that have an effective and safe Integrated Pest Management strategy of stored grains pests

and their products.

Keywords: Tribolium confusum; adults and of larvae; medicinal plants; essential aromatic

oils; leaf powders; phytotoxicity.

المقدمة

ثروة نباتية غنية جدا وعددا كبيرا من الأنواع المتنوعة من النباتات على وجه التحديد، والنباتات الطبيعة منحتنا

الطبية التي نمت في أجزاء مختلفة من العالم المعروفة بغناها كمورد للعقاقير لأنظمة الطب التقليدية الحديثة،

لصيدلانية، والكيانات الكيميائية للعقاقير الاصطناعية، الوسائط اووالمغذيات، والمكملات الغذائية، والطب الشعبي،

النعناع كوتعتبر النباتات الطبية (Madubuike et al., 2018).ومكافحة آفات وأمراض الصحة العامة والزراعة

، L. Ocimum basilicum )الحبق( ، والريحان الحلوL. Mentha rotundifolia قمستدير الأورا

Labill Eucalyptus globulus س الكافور أو السرول وكالبتو، والإيL. omaticumSyzygium ar والقرنفل

لى رأسها النباتية وع صدارة قائمة المبيدات الحشرية النباتية في مكافحة الآفات والأمراضمن النباتات الطبية على

آفات الحبوب المخزونة ومنتجاتها.

الأغذية الهامة لحياة الانسان حيث يتم حفظها في المخازن وصوامع الحبوب الكبيرة بعد الحصاد منالحبوب

يق المتشابهة الدقتعتبر خنفساء .والقوارض الحشريةبالآفات رضة للإصابة حتى الاستهلاك ويكون الانتاج ع مباشرة

Tribolium confusum رة خسا تسببو ،ومنتجاتهاالمخزونة التي تصيب الحبوب ةالاقتصادية الهام الآفاتمن

التلوث و الكثافة العددية الهائلة لخنافس الدقيق المتشابهةبسبب المحاصيل ودةوفي ج ،% 39 – 29كبيرة تصل إلى

هود ز الجزبالفضلات وبقايا إنسلاخات الأطوار والبيض. والمشاكل المرتبطة باستخدام مبيدات الآفات الكيميائية ع

المبذولة لإيجاد مركبات بديلة فعالة وآمنة وعملية. أظهرت الدراسات أن مبيدات الآفات لها آثار ضارة على صحة

57

خنفساء الدقيق المتشابهة الس مية النباتية للزيوت العطرية الأساسية ومسحوق الأوراق لأربعة نباتات طبية على البالغات ويرقات

الاستخدام المفرط والمستمر للمبيدات التي تسبب مشاكل ب، وذلك بسبرالبيئي للخطالإنسان وتعرض الإصحاح

ات مقاومة الآف ظهور، وملقحات الأزهار وأهمها نحل العسل، والبشر، وونخطيرة مثل التسمم المباشر للأعداء الطبيعي

,Tapondjon)ب والحبو لالحشرية للمبيدات، وتفشي الآفات وأمراض النبات، والمتبقيات السامة على المحاصي

2005; RafieianKopaei, 2012)

مزايا المبيدات الحشرية النباتية مثل السمية القليلة للإنسان، والحفاظ على البيئة، والملاءمة للتطبيقات الصغيرة،

تم استخدام .(Nasri and Shirzad, 2013)ية وتأثيراتها الواسعة تعتبر مناسبة كبديل آمن للمبيدات الحشرية الكيميائ

الطبية لمكافحة الآفات الحشرية في المستودعات وصوامع تالعطرية ومسحوق الأوراق للنباتا ةالزيوت الأساسي

تللأثر الفعال لخصائص مركبات الزيوت العطرية الأساسية ومسحوق الأوراق كمبيدا وذلك الحبوب لعدة سنوات،

.Sharafati-Chaleshtori, 2010))المصنعة نباتية وطارد للحشرات وبديلة للمبيدات الكيميائية

مقارنة بالدراسات في مكافحة الآفات الحشرية، تعد التجارب السمية للنباتات الطبية باستخدام الزيوت الأساسية

عن %2، وأقل من % 12.66؛ والتقييم بالتلامس نحو % 33.12العطرية ومسحوق الأوراق كمدخنات بنسبة تقدر

نسبة Coleopteraولحشرات المنتجات المخزونة كان لترتيب الدراسة والبحث رتبة الخنافس طريق الابتلاع.

من % 79نسبة S. Oryzaeوسوسة الأرز T. castaneum، وشكلت أنواع خنافس الدقيق الحمراء % 27.32

تمثل العته الهندية من التجارب حيث ٪22.33 في قرابة Lepidopteraالدراسة. تم استخدام حشرات رتبة حرشفية

Plodia interpunctella وعته الفواكه الجافةEphestia kuehniella غالبية الدراسات التي أجريت على هذه

Liposcelisفي قمل الكتب Psocopteraالدراسات المتبقية متعلقة الجوانب برتبة قمل الكتب. الآفات الحرشفية

bostrychophila الرتبةفي جميع الدراسات التي تنطوي تحت هذه التي استخدمت تقريبا .(Campolo et al.,

2018)

,diterpenes, steroidsيعتبر النعناع مستدير الأوراق كمصدر غني بالمركبات الكيميائية النشطة النباتية مثل:

lignans, stilbenes, phenols, essential oils, tannin, flavonoids, glycosides, alkaloids,

coumarin, saponin,.؛ التي تعتبر مضادات نشطة للكائنات الدقيقة الممرضة والآفات الحشرية

(Sachinkumarm et al., 2016; Ganesan, 2020)

فحص وب .)الحبق( في الريحان الحلو flavonoidsن أن هناك أنواعا مختلفة من مركبات يالباحث الكثير من ادأف

منها: مركب كيميائي نباتي 199أكثر من أظهريائية النباتية للريحان الحلو من خلال عدة دراسات كونات الكيمالم

limonenemyrcene, terpinolene, flavonoids, essential oil, phenolic acids, steroids,

(Marvat et al., 2011) أما .eugenol الرئيسي في الزيت الأساسي العطري للقرنفل المسؤول نيعتبر المكو

,alkaloid, tanninوأهم المركبات النشطة الكيميائية النباتية للقرنفل تتمثل في .الأول عن الخصائص الطبية

saponin, essential oil, flavonoid, phenol, steroid, glycoside, terpenoid لذا يعتبر نبات القرنفل .

تات الهامة في المجالات الطبية، الطب الشعبي، وفي مكافحة العديد من الآفات الحشرية والأمراض النباتية من النبا

et al., 2018) Madubuik لأوراق إيوكالبتوس وجود مادة كل من: أظهر التحليل الكيميائي النباتي (. مقارنة

saponins, quinone, essential oil, tannin, flavonoid, methanol, hexane and ethyl alkaloids,

phenolic compounds, acetate, steroids, glycosides, terpenes (Ishnava et al., 2013; Coppen,

2019; Kaur et al., 2019) .

وجد الباحثون أن الزيوت الأساسية العطرية ومسحوق الأوراق والمكونات الكيميائية لديها سمية نباتية كبيرة ضد

رد أو منفر ومبيد للحشرات، ومبيد ، وأن طرق التأثير تتمثل في كونها: طاT. confusumافس الدقيق المتشابه خن

(.Pandey et al., 2018لكل من البيض واليرقات والعذارى، ومانع للتغذية ووضع البيض )قييم أظهرت الدراسات أن ت. حشرات المخازن تتستعمل مساحيق النباتات الطبية لوقاية الحبوب ضد آفا اتقليدي

واليرقات زيادة نسبة الموت ةمسحوق أوراق النباتات الطبية على حشرات حبوب القمح المخزونة للأطوار البالغ

تختلف طريقة عمل مسحوق أوراق النباتات الطبية قد و .بنسب معنوية مع زيادة مستوى التركيز والزمن المعر ض له

Cinnamomumالجرعات المستخدمة. كما ت بين أيضا أن مسحوق قلف القرفة والتأثير الطارد أو السام حسب

annum له تأثير طارد لخنافس حبوب الذرةSitophilus zeamais ؛ ومسحوق جذور النبات العشبي الهنديInula

58


racemosa طارد لخنافس الأرزS. oryzae (Mahfoud, 2004; Dhaniya and Dayanandan, 2016;

Rajasekhar et al., 2012; Ziaee, and Moharramipour, 2013.)

تركيزات ثلاث تشبه أوراق الغار في Peumus boldusشجرة الكبد مسحوق من الحشرات دتأثير مبي تقييم تم

الموت الطارد، وتأثير الأفضلية، للمعايير: من القمح أصناف على S. zeamaisالذرة خنفساء لمكافحة مختلفة

وأوضحت النتائج تأثيرات معنوية لهذه المعايير لمسحوق أوراق شجرة الكبد . والإنبات البالغة، الحشرات وظهور

العطرية الزيوت أن (. الدراسات السابقة تشيرCruzat et al., 2009على خنافس الذرة بالتركيزات المختلفة )

مختلفة من طرق طعبر أنما Triboliumأنواع خنافس جنس على كبيرة لها سمية الكيميائية وناتهاومك الأساسية

الحشرات، ومبيد لليرقات والعذارى، والأثر على وضع البيض، ومضاد للتغذية والأعصاب العمل كطارد، ومبيد

(Pandy et al., 2018).

الدراسات والبحوث الليبية في مجال استخدامات مستخلصات النباتات الطبية السائلة والزيوت الأساسية العطرة

ومسحوق الأجزاء الخضرية والجذور في إدارة ومكافحة آفات حشرات الحبوب المخزونة ومنتجاتها الغذائية، تكاد

السمية للزيوت تقييم الأثارف هذه الدراسة له تهد. علي;Mahfoud, 2004) 1922تكون محدودة )طلحة ومحفوظ،

؛ M. rotundifoliaالأساسية العطرية المتوفرة تجاريا ومسحوق أوراق أربع نباتات طبية: النعناع مستدير الأوراق

E. globulusأو السرول الكافوروس وكالبت؛ أيS. aromaticum ؛ القرنفل O. basilicumلو )الحبق( لريحان الحاول وإثراء هذا البحث بالمعارف ح. معمليا ليافعة من خنافس الدقيق المتشابه الحشرات البالغة ومراحل اليرقات اعلى

.فعالية مكونات النباتات الطبية الشائعة "المبيدات الخضراء" للحبوب المخزونة ومنتجاتها الآمنة والصديقة للبيئة

المواد وطرق البحث

النباتات الطبية قالنباتية الحشرية للزيوت الأساسية ومسحوق أورااختبار أثر السمية باستخدام تربية مستعمرات 1923سنة جريت التجارب في معمل قسم علم الحيوان، كلية العلوم، جامعة طرابلسأ

تمت تربية الحشرات البالغة في حاضنات على نظام غذائي مخلوط. T. confusumالدقيق المتشابهة من خنافس

± 12 الظلام،ساعات في 2 ساعة، 26الفترة الضوئية لمدة عند(، وحفظها ا وزن 2.7: 29بدقيق القمح مع الخميرة )

و أ تم تقييم أثر المبيدات الحشرية للزيوت العطرية بطريقة التلامس رطوبة نسبية. ٪79 - ٪69 مئوية،درجة 2

.©Whitmanالتي طبقت باستخدام ورق الترشيح التدخين

تمت إذابة الزيوت العطرية لكل من نبات النعناع، والريحان، والقرنفل، وإيوكالبتوس في الكحول الإيثيلي النقي

( لكل محلول منهم. وزع كل مستحضر على سطح ورق الترشيح v/v) %99، 19، 29كمذيب بثلاث تركيزات

وبمجرد تبخر المذيب وضع دقائق 29بعد سم(. 2سم، ارتفاع 3ووضعه بعد ذلك في أطباق بتري زجاجية )قطر

من اليرقات من الأعمار الثالثة إلى الرابعة في كل طبق بتري زجاجي 79من الخنافس البالغين الإناث والذكور، 79

في نفس درجة الحرارة وظروف الرطوبة النسبية مجم من دقيق القمح الصافي وحفظه 7على حده يحتوي على كل

المطلوبة.

مكررات لكل محلول بما في ذلك الشاهد كعنصر من الغذاء فقط لكل معاملة لمحاليل نباتات الزيوت عملت أربع

جم مسحوق أوراق 2الاساسية بالتركيزات المذكورة سابقا. وللمقارنة تم القيام بنفس المكررات وطريقة العمل على

افي، واستخدام الدقيق كشاهد على التجربة. جم من دقيق القمح الص 7كل نبات في أطباق بتري الزجاجية مخلوط مع

ساعة بعد الحث بفرشاة دقيقة على عدم إظهار أي حركة. قيمت 71البالغة واليرقات بعد تتم تحديد موت الحشرا

وتمت مقارنة الفروق المعنوية بين المتوسطات باستخدام اختبارات ANOVAالبيانات بواسطة تحليل التباين

. LSDالانحراف المعياري

النتائج

59


مستدير الأوراق النعناع تم اختبار السمية النباتية للزيوت العطرية الأساسية ومسحوق الأوراق لأربعة نباتات طبية:

rotundifoliaM. ،و )الحبق( لريحان الحلاO. basilicum القرنفل ،S. aromaticumس وكالبتو، إيE.

globulus على طور البالغات واليرقات اليافعة لخنفساء الدقيق المتشابهة .T.confusum 723.3كان أثر التداخلات

على Fواضحا بفروق معنوية عالية عند قيمة 191.26وأطوار خنفساء الدقيق المتشابهة 7.62بين المعالجات

سمية الزيوت العطرية الأساسية ومسحوق أوراق رأث Fواختبار ANOVAالتوالي. أظهرت نتائج تحليل التباين

بفروق معنوية عالية T.confusumرقات اليافعة لخنفساء الدقيق المتشابهة النباتات الطبية على موت البالغات والي

(.2. )جدول9.992عند مستوى

خنافسلأثر تركيزات الزيوت ومسحوق أوراق النباتات الطبية على موت أطوار ANOVA. تحليل التباين 2جدول

.T.confusumالدقيق المتشابهة _____________________________________________________________________________________

F X2 df SQ Source

31.969** 1505.836 710540.854a النموذج المصحح

514.994** 24258.062 2 24258.062 التداخلات

المعالجات 803.743 3 276.814 **5.688

واليرقاتالبالغات 9522.50 1 9522.507 **202.161

الخطأ 6406.0 136 47.104

الإجمالي 16946.93 143

_____________________________________________________________________________________

.9.992** مستوى الثقة المعنوي عند مستوى

النباتات الطبية اختلافا كليا عند استخدام مستخلصاتها من الزيوت العطرية الأساسية ومسحوق الأوراق في تختلف

الزهري والقمي، الجزء الخضري المعاملة مع آفات حشرات الحبوب المخزونة ومنتجاتها، من حيث الأنواع، الجزء

من الأوراق والسيقان، والجذور من النبات؛ بالإضافة إلى جغرافية النباتات ومنشأها. كانت الفروق المعنوية للمعالجات

،)29.22، إيوكاليبتوس 5.81، القرنفل 5.67الريحان )النعناع . 1(، 7.67النعناع )الريحان . 2: بين النباتات الطبية

النتائج أوضحت (.2.69-، القرنفل 9.22)الريحان إيوكاليبتوس. 3(، 1.63، إيوكاليبتوس 7.22)الريحان القرنفل. 9

أن مقارنة المعالجة بالنباتات الطبية من النعناع والقرنفل والإيوكالبتوس، بأن للريحان الحلو أثر سمي بفروق معنوية

. يلي ذلك T. confusumاليافعة لخنفساء الدقيق المتشابهة على البالغات واليرقات 9.97، 9.992عالية عند مستوى

الأثر السمي للنباتات الطبية القرنفل والإيوكالبتوس على التوالي، مقارنة بأثر نبات النعناع الذي لم يضفي أثرا سميا

.(1)جدول T. confusumمعنويا على البالغات واليرقات اليافعة لخنفساء الدقيق المتشابهة

، لأثر سمية معالجة الزيوت الأساسية LSD. العلاقات والتداخل بين المتوسطات والانحراف المعياري 9ح جدول يوض

دقيق الخنافس العطرية ومسحوق أوراق النباتات الطبية الأربعة على موت الحشرات البالغة واليرقات اليافعة ل

.T. confusumالمتشابهة

61

مصطفى الصغيرو بثينة نوال عبد السلام محفوظ

لأثر سمية معالجة الزيوت ومسحوق أوراق النباتات الطبية على موت أطوار LSD يالمعيار لانحراف. ا1جدول

.T. confusumالدقيق المتشابهة سخناف

الاحتماليةالقيمة الانحراف المعياري

LSD

الفرق المعنوي

- )س( )ص(

المعالجة المعالجة

)ص( س( )

.000**

.961

.054

1.309

1.309

1.309

5.67*

-.14-

2.56

النعناع الريحان

القرنفل

وكالبتوسإي

.000**

.000**

.019*

1.309

1.309

1.309

-5.67-*

-5.81-*

13.11-*

النعناع الريحان

القرنفل


.916

.000**

.042*

1.309

1.309

1.309

.14

5.81*

2.69*

ل القرنف

لنعناعا

الريحان


.054

.019*

.042*

1.309

1.309

1.309

-2.56-

3.11*

-2.69-*

النعناع وكالبتوسإي

الريحان

القرنفل

9.97* مستوى الثقة المعنوي عند مستوى 9.992** مستوى الثقة المعنوي عند مستوى

تظهر النتائج فروقا معنوية واضحة الأثر السمي لنوع الزيوت العطرية الأساسية بين النباتات الطبية المستخدمة

)جدول 9.992وعند مستوى 3.9وانحراف معياري 7.3حيث أظهر الريحان فروقا معنوية بين باقي الزيوت بمتوسط

فروقا معنوية بينهم بينت النتائج T. confusumالدقيق المتشابهة خنافس والأطوار البالغة واليرقات اليافعة لأ(. 9.

ا معنويا للسمية بين تركيزات الزيوت العطرية الأساسية الثلاث بينما لم يتضح أثر ب(. 9)جدول . 9.992عند مستوى

29% ،19% ،99% (v/v بمتوسط )ولحالة أو صيغ النباتات الطبية ج(. 9)جدول .على التوالي 3.7، 22.1، 22.3

أنوع الزيوت بمستوى فروق معنوية عالية xللزيوت العطرية الأساسية والمسحوق، حيث أظهر تداخل المعالجة

حالة النباتات xواليرقات ةالأطوار البالغ xواليرقات، والمعالجة ةالأطوار البالغ x؛ أما تداخل المعالجة 9.992عند

د(. 9)جدول 9.97بينت النتائج فروق معنوية عند مستوى

ج( التائهة، )للعلاقات بين )أ( نوع زيوت النباتات، )ب( أطوار خنفساء الدقيق (LSD) . الانحراف المعياري9جدول

تركيز زيت النبات، )د( حالة النبات ومراحل حياة الخنفساء.

أ. نوع زيوت النباتات.

§الاحتماليةقيمة ال لعلاقاتا

§الانحراف المعياري ±المتوسط نوع زيت النبات

O. basilicum 3.9 ±7.3 b و الريحان الحل

E. globulus 12.4± 8.0 a س وكالبتوإي

M. rotundifolia 22.7±27.9 aالأوراق رمستدي النعناع

S. aromaticum 23.7±27.2 aالقرنفل

P≤0.001))الاختلاف

أطوار خنفساء الدقيق التائهة.

§يالانحراف المعيار± المتوسط واليرقات البالغة الأطوار

a 3.7± 12.2 طور يرقي

b 9.1±3.3 الطور البالغ

P=0.001 §معنوية المتوسطات التي المتبوعة بنفس الأحرف غير

61


ج. تركيز زيت النبات. §يالانحراف المعيار± المتوسط )%( النبات زيت تركيز

10 29.9 ±22.3 a

20 23.9 ±22.1 a

30 22.7 ±3.7 a

P=0.258 الأحرف غير معنوية سالتي المتبوعة بنف المتوسطات§

النبات.د. تركيز زيت §مراحل الحياة حالة النبات

حالة النباتاتصيغ الزيت ومسحوق

الأوراق

الريحان الحلو

O. basilicum


E. globulus

مستدير الأوراقالنعناع M. rotundifolia

لالقرنف

S. aromaticum

.9 واليرقات تأطوار البالغا 299 **

2.790 النبات زيت تركيز

.9 الزيت عاانو x المعالجة 299 **

*9.420 واليرقات ةلأطوار البالغا x المعالجة

2.589 النبات تركيززيت xت واليرقا ةالأطوار البالغ

حالة xت واليرقا ةلأطوار البالغا xالمعالجة

تالنباتا

0.020*

P≤0.05)) ياختلاف معنو*

P≤0.001)) ياختلاف معنو**

المناقشة

بواسطة الزيوت العطرية الأساسية Coleopteraتتعلق برتبة الخنافس التي الحشرات لالعديد من فصائ تقييمتم

Tenebrionidaeوفصيلة الظلاميات Curculionidaeومسحوق أوراق النباتات الطبية، خاصة فصيلة السوسيات

وتظهر .حبوب المخزونة ومنتجاتها كثيرة التباينومع ذلك؛ فإن أثار السمية لها على معدل وفيات أنواع آفات خنافس ال

، أن عدد قليل S. oryzaeنباتا طبيا على سوسة الأرز 19دراسة تقييم الأثر السام للزيوت العطرية الأساسية لعدد

(. أوضحت نتائج هذا Abdelgaleil et al., 2016فقط من النباتات لها أثر قاتل للحشرات عن طريق الملامسة )

سمية الزيوت العطرية الأساسية ومسحوق أوراق النباتات الطبية على موت البالغات واليرقات اليافعة أثرالبحث

. ولم توضح النتائج أية 9.992ساعة فروق معنوية عند مستوى 71بعد T. confusumلخنفساء الدقيق المتشابهة

%99، %19، %29يزات المخففة بالكحول الإيثيلي التركمع فروق معنوية بين حالتي النباتات من الزيوت الأساسية

(v/v) جم عند خلطها مع الدقيق، على موت البالغات واليرقات اليافعة لخنفساء الدقيق 2ومسحوق الأوراق بوزن

عار الطيارة بواسطة قرون الاستش ةسرعة نقل الشفرة الكيميائية للزيوت الأساسيمدى رجح ذلك على المتشابهة، وي

للأطوار البالغة، وعبر القصبات الهوائية لليرقات وسط الدقيق. وتشير الدراسات أن سمية مدخنات الزيوت ةبالنسب

وسمية .تشير بشكل رئيسي إلى الأطوار البالغة Tenebrionidaeخنافس الدقيق الحمراء العطرية الأساسية تجاه

تبد ةيتم التحقيق فيها بشكل يذكر، وأن الأطوار البالغالزيوت العطرية الأساسية نحو اليرقات، والعذارى، والبيض لم

(. إلا أن استخدام اليرقات اليافعة لخنفساء الدقيق Suthisut et al., 2011) ةمن المراحل غير الناضج ةأكثر عرض

في هذه الدراسة، أظهرت مستوى فروق معنوية عالية للسمية ليرقات خنافس الدقيق T. confusumالمتشابهة

متشابهة. ال

بات واضحا من النتائج أن مقارنة المعالجات بالنباتات الطبية من النعناع والقرنفل والإيوكالبتوس بأن للريحان

على البالغات واليرقات اليافعة لخنفساء الدقيق 9.97، 9.992الحلو أثر سمي بفروق معنوية عالية عند مستوى

مي للنباتات الطبية القرنفل والإيوكالبتوس على التوالي. المنتج المشتق . يلي ذلك الأثر الس T. confusumالمتشابهة

خنافس الدقيق من جنس كويستخدم في مكافحة حشرات الحبوب المحزونة ومنتجاتها Mentholالرئيسي من النعناع

Tribolium (Halit et al., 2012, Lashgari et al., 2014) . الأوراقمقارنة بأثر نبات النعناع مستدير

62


rotundifolia M. الذي لم يضفي أثرا سميا معنويا بل منفرا على البالغات واليرقات اليافعة لخنفساء الدقيقT.

confusum 99، %19، %29ساعة لتركيزات سمية الزيوت العطرية الأساسية 71بعد% (v/v) ومسحوق أوراق

أظهرا مستوى فروق معنوية Eugenolبمفعول والقرنفل ،النبات المستخدمة عند خلطها مع الدقيق. الإيوكالبتوس

وكانت النتائج متوافقة مع T. confusumبأثر منفر على البالغات واليرقات اليافعة لخنفساء الدقيق 9.97عند

.(Hamdy et al., 2016; El-Gizawy et. al., 2019; Naseem et al., 2011) الدراسات السابقة

. أما 9.992أنواع الزيوت بوجود مستوى فروق معنوية عالية عند xكما أتضح من النتائج أن تداخل المعالجة

حالة النباتات أظهر فروق معنوية xواليرقات ةالأطوار البالغ xواليرقات؛ المعالجة ةالأطوار البالغ xتداخل المعالجة

كذلك أن سمية الزيوت العطرية ومسحوق الأوراق للنباتات الطبية المختبرة، القدرة كمواد وتبين. 9.97عند مستوى

.إستراتيجيات مكافحة الآفات بطرق الملامسة أو التدخين آمنة المخاطر بيئيا في فعالة على هذه الآفة الاقتصادية

تجارب تكميلية في ظروف أماكن تخزين الحبوب ومنتجاتها ميدانيا.وينبغي إجراء

معدل سعر 1911بحلول سنة قدر ي عالميا هائلا النباتية اليوم سوقاالعطرية تمثل الزيوت الأساسية الختام،في

النعناع، خاصة منتجا، 27من هذا الإنتاج على ٪ 39ويركز (Ridder, 2020) بليون دولار 17.33السوق بنحو

روم والصنوبوالث ، الإكليل، الزعتر،، القرفة، اللافندرالحمضيات، الصنوبر، القرنفل، الحمضيات، الريحان، رالكافو

يمكن أن يكون الاستخدام المتنوع للزيوت الأساسية من خلال تطوير استخدامها في قطاع والشاي. أشجار وزيوت

ستخدامها لا المتنوعة مفيدا اقتصاديا وبيئيا. ليبيا أرض واعدة من النباتات الطبية المكافحة المتكاملة للآفات إدارة

. والمكسرات ر والفواكه المجففةوالحبوب والتمات المنتجات المخزونة كفات حشرآكزيوت أساسية في مكافحة

تقديرشكر و

يد. حنان حسين الشتيوو مساهمة في تقديم المشورة العلميةلل الشكر موصول إلى كل من أ. د. حسن أحمد المغربي

د يد م قسم علم الحيوان، كلية العلوم، جامعة طرابلس. كما نتقدم بجزيل الشكر إلى كل من - للقيام بالتحليل الاحصائي

المساعدة لإنجاز هذا البحث، والله ولي التوفيق.

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خنفساء الدقيق المتشابهة للزيوت العطرية الأساسية ومسحوق الأوراق لأربعة نباتات طبية على البالغات ويرقاتالس مية النباتية

[7] El-Gizawy, K. KH., Halawa, S. M., Mehany, A. L. and Mohamed, S. A. (1923) .

Toxicity of some Essential oils and its Biochemical Effect against Red Flour Beetle,

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pharmacological updates on Peppermint (Mentha iperita L.)-A review. Phytotherapy

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inhibitory effects on acetylcholinesterase and adenosine triphosphatases, Natural

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species against granary weevil [Sitophilus granarius L. (Coleoptera: Curculionidae)].

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[12] Kaur, S.; Saurabh, G. and Priyae, B. G. (2019). Phytochemical analysis of Eucalyptus

leaves extract. Journal of Pharmacognosy and Phytochemistry, 8(1), 2442-2446.

[13] Lashgari, A., Mashayekhi, S., Javadzadeh, M. and Marzban, R. (2014). Effect of

Mentha piperita and Cuminum cyminum essential oil on Tribolium castaneum and

Sitophilus oryzae. Archives of Phytopathology and Plant Protection, 47(3), 324-329.

[14] Madubuike, P., David E., and Nnetochukwu, M. (2018). Phytochemical screening of

Eugenia 11. Caryophyllata (clove leaves) and characterization of its essential oil.

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[15] Mahfoud, N. A. (2004). Food preference of flour beetle Tribolium confusum

(Coleoptera: Teneberionidae). Unpublished MSc. Thesis, Dept. Zool. Science, Univ.

Tripoli ‒ Libya.

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Usman, K. H. (2011). Phytochemical constituents and pharmacological activities of

sweet basil-Ocimum basilicum L. (Lamiaceae). Asian J. Chem., 23, 3773–3782.

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against red flour beetle Tribolium castaneum Herbst (Coleoptera:

Tenebrionidae). Journal of Stored Products and Postharvest Research, 2(7), 131-134. [19] Pandey, A. K., Tripathi, S., & Singh, P. (2018). Plant essential oils: a substitute for

conventional insecticides against Tribolium species (Coleoptera: Tenebrionidae)-

achievements and challenges. Archives of Phytopathology and Plant

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Plarmacol., 1(1), 1-2.

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grain protectants. Psyche, 1-13.

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[23] Sachinkumarm, R., Rahul, S. P. and Godghate, A. G. (2016). Mentha piperita L:

Phytochemical, Antibacterial and Dipterian Adulticidal Approach. Dr. Ghali College,

Gadhinglaj 416502 (M. S.), India.

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effects of ethanolic extract of walnut leaves (Juglans regia) on Propionibacterium

acnes. J Zanjan Univ Med Sci Health Serv., 18(71), 42-49.

[25] Suthisut, D., Fields, P. G., & Chandrapatya, A. (2011). Fumigant toxicity of essential

oils from three Thai plants (Zingiberaceae) and their major compounds against

Sitophilus zeamais, Tribolium castaneum and two parasitoids. Journal of Stored

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65


Effects of Blend Composition on the UV Stability of Polyethylene Blends

Anour Shebani*, Abdalah klash, Rabia Elhabishi, Shalh Abdsalam, and Wael Elhrari

Libyan Polymer Research Center, Tripoli-Libya

*[email protected]

Abstract

The main goal of this study was to investigate the effects of blending composition

on the UV stability of different polyethylenes (PEs). This would help in having a

good understanding of modifying these materials in different ways, to make them

suitable for different target applications. The susceptibility of different blends of

low density polyethylene (LDPE) and high density polyethylene (HDPE) to UV

degradation were investigated. LDPE/HDPE blends with varying ratios (80/20,

60/40, 40/60, and 20/80), were prepared by melt-mixing technique using mini-

twin-extruder. The LDPE, HDPE and their blends were conducted and exposed to

UV-B light (340nm) for 415h in accelerated weathering test machine. To follow

the degradation and to characterize the surface changes of LDPE, HDPE and their

blends, fourier transform infrared spectroscopy (FTIR), contact angle

measurements and optical microscope were utilized. It was observed that the

susceptibility of LDPE/HDPE blends to degradation varied according to blending

composition. Blends-rich with HDPE possess better resistance to UV degradation

than virgin LDPE and blends-rich with LDPE. Moreover, blend with the

composition of LDPE (20)/HDPE (80) was less susceptible to UV degradation

than other blends. In line with previous study, blending composition could be

used as indicator to predicate the final properties and suitable application of the

final LDPE/HDPE blend.

Key words: LDPE; HDPE; UV degradation; blending; properties

خصستالم

أنواع مختلفة من متعدد الإيثيلين على ثبايته عند تعرضه للأشعة الفوقتهدف الدراسة الى التحقق من تأثير خلط

(. هذا من شأنه أن يعطي نتائج تساعد في فهم تأثير عملية الخلط لتحسين خواص هذه البوليمرات UVبنفسجية )

لجعلها مناسبة لبعض لتطبيقات. تم في هذه الدراسة خلط نسب مختلفة من متعدد إيثيلين منخفض الكثافة

(LDPE( ومتعدد إيثيلين عالي الكثافة )HDPE ودراسة تأثير أشعة )UV عليها. حيث تم تحضير خليط من

LDPE/HDPE ( بواسطة ألة البثق ثنائية المحور. تم 19/29، و 39/69، 69/39، 29/19بنسب مختلفة )

ساعة باستخدام 327( لمدة nm UV-B 340) UVتعريض البوليمرات الاساسية والمخالط البوليمرية لاشعة

صندوق التجوية الاصطناعية. متابعة التغيرات في الخواص السطحية للبوليمرات والمخاليط المعرضة للأشعة

تم بواسطة اجهزة مثل جهاز مطيافية الأشعة تحت الحمراء وجهاز قياس زاوية التلامس والمجهر الضوئي.


66


أشارت النتائج إلى أن التغيرات في الخواص السطحية للمخاليط تتفاوت وفقا لمكونات كل مخلوط بوليمري.

والمخاليط الغنية بـ LDPEمن UVتتميز بمقاومة أفضل لأشعة HDPEفالمخاليط البوليمرية الغنية بـ

.LDPE كما بينت الدراســـــة بأن أفضــــــل ثباتية وأكثر مقاومــــــــة كانت للمخلوط المكـــــــون من

LDPE (20) / HDPE (80)) مقارنة بباقي المخاليط البوليمرية. وبالتوافق مع دراستنا السابقة يتضح بأن )

عدد الإيثيلين من شأنها أن تستخدم كمؤشر لتوقع الخصائص النهائية نسب وعمليات خلط الانواع المختلفة من مت

.(LDPE/HDPE)والتطبيق المناسب للمخاليط البوليمرية

Introduction

Polyethylene (PE) is one of the most used polymer in modern society. PE is a name

given to different types of polymer; low density polyethylene (LDPE), linear low density

polyethylene (LLDPE) and high density polyethylene (HDPE). These grades are divided

based on density and branching. They have the same chemical formulas and their overall

properties depend significantly on variables such as the extent and type of branching, the

crystal structure and the molecular weight [1-2]. They have been used in many

applications owing to the excellent mechanical properties such as high drawability,

toughness, workability, lightweight and so forth [3]. PE is a consumer polymer which can

be used in applications ranging for films, tubes, pipes, plastic parts, laminates, etc. in

several markets (packaging, automotive, electrical, agriculture, etc.).

Among these three grades of PE; LDPE is the most widely used PE grade, due to its

relatively good mechanical and optical properties, combined with a competitive market

price [4]. LDPE is known to has good properties, such as: high flexibility, good

processability, impact resistance, dimensional stability and excellent resistance to dilute

acids, alcohols, bases and esters [5]. In actual fact, LDPE plays a key role in the industry

of PE due to its wide range of applications. On the other hand, HDPE has a stronger

intermolecular forces, higher density and greater proportion of crystalline regions than

LDPE. The size and size distribution of crystalline regions are determinants of its

properties. HDPE is used in the production of plastic bottles, corrosion-resistant

piping, geomembranes and plastic lumber. Although all PE grades are at the top of the

list of commodity polymers, they are susceptible to degradation.

Polymer degradation is a change in the properties of a polymer under the influence of

one or more environmental factors such as heat, light (UV radiation), mechanical stress

or chemicals. Degradation could be defined as a change in the chemical structure of a

plastic involving a deleterious change in properties [6]. Degradation in general may occur

during processing, manufacturing, storage and end use. PE grades can absorb solar UV

radiation and undergo photolytic, photo-oxidative, and thermo-oxidative reactions that

result in the degradation of these materials. This could cause catastrophic failure and

shorten their useful lifetime [7]. It has been stated that the hierarchy in the oxidation

susceptibility of PE is as follows: LDPE > LLDPE > HDPE [8-10]. The susceptibility of

a polymer to degradation depends on its structure. Basically, the susceptibility of a

polymer to degradation would depend on the chemical composition, molecular weight,

crosslink density, degree of crystallinity, and environmental degrading conditions [11-

12].

67


UV radiation and oxygen are the most important factors that initiate degradation,

leading to release a free radicals. Subsequently chain scission takes place. The physical

and mechanical properties of the polymer deteriorate and its average molecular weight

(chain length) decreases, melt flow rate increases, degree of crystallinity increases and a

powdery surface eventually forms [13-15]. Moreover, degradation products such as

alkanes, alkenes, ketones, aldehydes, alcohols, carboxylic acids, keto-acids, linear esters

and lactones could be formed [16]. However, studying the degradation process of

polymers is crucial. The usefulness of any material, including polymer blends, depends

on its degradability and durability [17]. For example, polymers which used as a building

materials, especially in outdoor applications should be highly resistance to degradation.

This is because it is difficult and expensive to repair or replace them. The main techniques

used to evaluate the polymer degradation could be divided into surface analysis (infrared

spectroscopy, optical microscope, scanning electron microscope, contact angle

measurements, etc.), and techniques to study changes in bulk analysis (molecular weight,

degree of crystallinity, weight loss, etc.) such as gel permeation chromatography,

differential scanning calorimetry, thermogravimetric analysis [18].

Blending technology could be used to either enhance the resistance of polymer to UV

degradation or to increase their susceptibility towards UV degradation. According to

many studies [12, 19], for most of the polymer materials, blending is the first choice and

a classic way to enhance their UV resistance. The resistance of polymers such as PE to

UV degradation could be enhanced by the use of additives which absorb the UV radiation

(e.g. stabilizers or blockers), or by coating or blending with another polymer which is

opaque to UV radiation. Other studies [16-20] claimed that the susceptibility towards

degradation could be enhanced by introducing UV absorbing groups along the PE chain

or by blending PE with UV absorbing additives or blending with functional polymers and

compounds. Other properties such as physical, mechanical, electrical, rheological is

known to improve by blending [21-22]. Therefore, the major objective of this study is to

investigate the effects of blending composition on the UV stability of LDPE/HDPE

blends. On the basis of the above facts and information, it seems possible to play with the

UV stability of PE and their blends by blending one grade of PE such as LDPE with other

PE grade such as HDPE. In a previous study [23], mechanical properties of LDPE/HDPE

blends were investigated. The results of this study demonstrated that the mechanical

properties of LDPE/HDPE blends were varied according to HDPE content. Consequently,

gathering the results of the current study with the previous ones would provide more

understanding and insights about the properties and applications of these blends

associated with their composition.

Experimental

Materials

The polymers used in this study are commercial grades; LDPE from Lyondel Basell

(PE 1840H) and HDPE from Ras Lanuf Co. (Libya) (HDF-5116). The melt flow index

(MFI) and density values of LDPE are 1.5 g/10min (ASTM D 1238, 190 ᵒC, 2.16kg) and

68


0.919 g/cm3 (ASTM D 1505, 23 ᵒC), respectively. LDPE (PE 1840H) can be used for

blow-fill-seal applications such as bottles, vials and healthcare applications like caps,

closures, collapsible tubes, medical devices and medical films. Whereas the melt flow

index (MFI) and density values of HDPE are 0.15g/10min (ASTM D1238, 190 ᵒC,

2.16kg) and 0.951g/cm3 (ASTM D 1505, 23 ᵒC), respectively. This type of material is

suitable for general purpose of film applications such as bags, liners, barrier film,

agriculture mulching film and co-extrusion film.

Blending process

LDPE/HDPE blends with varying ratio (80/20, 60/40, 40/60, and 20/80), were

prepared by melt-mixing technique using mini-twin-extruder (Haake mini CTW twin

screw) with average screw speed of (90 rpm.), and the barrel temperatures set on 200 ᵒC.

The specimens for accelerated weathering test were prepared using mini-injection mould

(Xplore 12ml) at melting temperature 230 °C, injection pressure (1.6 MPa), and holding

time (6 s).

Accelerated weathering test

The LDPE, HDPE and their blends were conducted and exposed to UV-B light (340

nm) for 415 h (~ 17 days of 4 periods/seasons) in accelerated weathering test machines

(Teemi880, china). The test consisted of four cycles that simulates day, night, rain, and

condensation according to the four seasons of the year. These cycles were started with

cycle of ~ 104 h of exposure to UV light at temperature of 40±2 °C, and relative humidity

of 80±5% (Summer season), followed by ~ 104 h of exposure to UV light at temperature

of 23±2 °C, and relative humidity of 20±5% (Spring season), followed by ~ 104 h of

exposure to UV light at temperature of 18±2 °C, and relative humidity of 15±5% (Autumn

season) and eventually followed by ~ 104 h of exposure to UV light at temperature of

8±2 °C, and relative humidity of 15±5% (Winter season). Samples had a length of 73 mm,

thickness of 2 mm, and wide of 4 mm.

Recognition of degradation

Fourier transform infrared spectroscopy (FTIR)

It is well known that the most suitable and sensible analysis for assessing polymer

degradation is fourier transform infrared spectroscopy (FTIR) [24]. FTIR (Bruker, Tensor

II) analysis of LDPE, HDPE and their blends was conducted using ATR-FTIR mode. All

spectra were recorded from 450 to 4000 cm-1 at a resolution of 4 cm-1.

Carbonyl index (CI) was use to estimate the degree of degradation of LDPE, HDPE

and their blenas before ana after acceleratea weathering test. Carbonyl groups’ formation

is an effective parameter for monitoring the photo-oxidation degree of PE and could be

presented as CI [25]. The content of carbonyl groups, formed by the oxidation of PE,

could be quantified by a CI obtained by dividing the stretching carbonyl band area (1718

cm-1) by the area of methylene group symmetric stretching vibration (2830 cm-1).

69


The CI of LDPE, HDPE and their blends before and after weathering was calculated

according to the following equation [26]:

CI =absorption at 1775 cm−1

absorption at 2830 cm−1

Contact angle

All the measurements were carriea out using Contact angle ramѐ-hart instrument co.

model 200-F4 at room temperature. 3 μl volume arops of water were aepositea on the

surface of the LDPE, HDPE and their blends using a syringe. Pictures of the water drops

were acquired through a digital camera positioned on a static contact angle analyzer. The

θ of the contact angle was measurea automatically from the image setup. Each contact

angel value is an average of 10 measurements and the standard deviation were calculated.

Optical microscope

Microscopic observations of LDPE, HDPE and their blends surface changes after

exposure to UV were carried out by means of an optical microscope (XP-501 transmission

polarizing microscope, Turkey), equipped with a color digital camera (Moticam 2) and

software Motic Images Plus 2 at different magnification.

Results and discussion

FTIR analysis

Fig. 1 shows the FTIR spectra of LDPE, HDPE and their blends recorded before and after

exposure to UV radiation. Fig. 1a shows that the main FTIR bands characteristics of PE

(both LDPE and HDPE) are the stretching vibration of carbon-hydrogen (CH) group of

the main chain at 2770-3040 cm-1 and the wagging and rocking vibration of methylene

(CH2) at 1430-1490 cm-1 and 690-750 cm-1, respectively [27-13]. This is because LDPE

and HDPE share the same major structural unit, functional groups, chemical bonds [30-

31] and therefore have many identical wavelength. However, the different degree of

branching results in small, but important differences. For example, FTIR spectrum of

HDPE in Fig. 1a shows a single band at 700-750 cm-1 and at 1440-1490 cm-1 because of

their linear structure [32]. These bands were appeared as two double bands in the case of

LDPE. Moreover, FTIR spectrum of LDPE in Fig. 1a had a unique characteristic band

(quite small) at 1375 cm-1, representing a methyl group (CH3) bending deformation of the

branched chain ends. This band was absent in the case of HDPE [32]. These results

indicate that even similar polymers such as LDPE and HDPE can be distinguished using

FTIR spectra. As can be seen in Fig. 1b, exposure to UV radiation caused significant

degradation of LDPE, HDPE and their blends. The most significant changes in FTIR

spectra after exposure to UV radiation were the carbonyl (1550-1740 cm-1), amorphous

(1260 cm-1) and hydroxyl regions (3400 cm-1). Thus, the bands at 1715 cm-1 for the

degraded LDPE, HDPE and their blends (shown in Fig. 1b) is due to the formation of a

variety of carbonyl groups, while the broadband between 3100 and 3600 cm-1 can be

assigned to the formation of hydroxyl and hydroperoxide groups [26]. The intensity of

71


2800 2100 1400 700

HDPE

80% LDPE

60% LDPE

40% LDPE

20% LDPE

Wavenumber, cm-1

LDPE

a

2800 2100 1400 700

Wavenumber, cm-1

HDPE

40%

LDPE

60%

LDPELDPE

HDPE

80% LDPE

60% LDPE

40% LDPE

20% LDPE

LDPE

3800 3600 3400 3200 3000

Wavenumber, cm-1

20% LDPE

80%

LDPE

b

Fig. 1. FTIR spectra for a) LDPE, HDPE and their blends b) LDPE, HDPE and their

blends after exposure to UV radiation.

these bands were somehow higher in the case of LDPE than in the case of HDPE,

suggesting that HDPE is less susceptible to degradation than LDPE, as reported in the

literature [33-35]. This is because LDPE is a branched polymer with a greater number of

tertiary carbon, which makes it more susceptible to undergo photo-oxidation reactions

[31]. Achilias et al. [36], cited that less crystalline or more branched polymers are less

stable during the degradation process. On the other hand, the intensities of the same

formed bands (carbonyl, hydroxyl and hydroperoxide groups) after exposure to UV

radiation as shown in the FTIR spectra in Fig. 1b of LDPE/HDPE blends decreased as the

71


amount of HDPE were increased in the blends, which indicate that the degradation was

decreased with increasing the amount of HDPE in the blend composition.

The CI of LDPE, HDPE and their blends before and after weathering was calculated

as shown above. According to Chiellini et. al. [33], carbonyl groups usually account for

most of the products of thermo-oxidative degradation of PE, their concentration, as

determined by the CI, could be used to detect the degradation. Generally, a higher value

of CI indicates a higher degree of polymer degradation [25]. Before exposure to UV

radiation, CI of LDPE were higher than that of HDPE as shown in Fig. 2. As mentioned

above, degradation could be introduced to the polymer during, manufacturing (e.g.

polymerization), processing (e.g. extrusion), storage and use [4]. Also, the results in Fig.

2 illustrates that the CI of LDPE, HDPE and their blends before exposure to UV radiation

were decreased as the HDPE content increased in the blend. This properly indicate that

the resistance of LDPE/HDPE blends to degradation was increased as the HDPE content

increased in the blend. Furthermore, it can be seen that, CI was increased after weathering

test (after exposure to UV radiation) for LDPE, HDPE and their blends. It can be also

observed that, even after weathering the resistance to degradation was increased as the

HDPE content increased in the blend.

0% 20% 40% 60% 80% 100%

63

70

77

84

91

After exposure to UV radiation

Before exposure to UV radiation

Car

bonyl

index

HDPE% in the blend

Fig. 2. Carbonyl index of LDPE, HDPE and their blends before and after exposure to

UV radiation.

Contact angle

It should be pointed out that obtained results characterize degradation mostly on the

surface of the LDPE, HDPE and their blends, while the degradation is supposed to be

significantly less present in polymer bulk [25]. As a matter of fact, degradation is

associated with chemical and physical changes taking place on the surface of polymer

[37]. For this reason, contact angle measurement (CAM) was performed in this study to

72


follow the degradation and detect the structural changes on LDPE, HDPE and their blends

surfaces. Ordinarily, the value of the contact angle can vary from 0-180o, 0o representing

fully wetted surfaces and 180o representing totally non-wettable surfaces [38].

Additionally, hydrophobic surfaces are characterized by a contact angle of 90o or more

and hydrophilic surfaces are characterized by a contact angle of less than 90o. In practical,

wettability and hydrophilicity are closely related phenomena. More wettability means

more hydrophilicity. However, CAM depends on several factors, such as surface energy,

wettability of the surfaces, viscosity of the liquid, roughness, the manner of surface

preparation, and surface cleanliness [39-40].

The values of the contact angle for LDPE, HDPE and their blends before and after

exposure to UV radiation are shown in Table 1. Standard deviations are given in

parentheses. The values of the contact angle for LDPE, HDPE and their blends before

exposure to UV radiation were varied from 73.2o (for LDPE) to 91.3o (for HDPE).

Normally, LDPE and HDPE are inherently hydrophobic polymers due to their non polar

surfaces. The hydrophilicity of LDPE could be due to the degradation, which may occur

during processing, manufacturing, and storage. It is important here to emphasis that the

resistance of LDPE to UV degradation improves by blending with HDPE and vice versa.

The values of the contact angle for LDPE, HDPE and their blends after exposure to

UV radiation were varied from 70.5o to 83.3o, as shown in Table 1. Exposure to UV

radiation caused decrease in the contact angle for LDPE, HDPE and their blends, as

shown in Table. This is obvious because the radiation under UV light increases the

hydrophilicity of PE surface by introducing of certain polar groups, as stated above. This

means that the surface of HDPE and their blends became hydrophilic.

Table 1. Contact angle and standard deviation of LDPE, HDPE and thier blends before

and after exposure to UV radiation.

Sample

Contact angle, ɵ

Before exposure to

UV radiation

After exposure to

UV radiation

LDPE 73.2o (1.1) 70.5o (3.6)

80%LDPE 85.4o (3.6) 79.1o (3.2)

60%LDPE 85.6o (3.6) 79.8o (3.1)

40%LDPE 85.8o (3.4) 80.2o (0.9)

20%LDPE 86.0o (1.3) 83.3o (3.1)

HDPE 91.3o (2.8) 79.9o (0.7)

Optical microscope

Surface degradation could be also investigated by optical microscope [41]. Optical

micrographs for LDPE, HDPE and their blends after exposure to UV radiation are shown

in Fig. 3. These micrographs support the FTIR and CAM results. More cracks were

present in LDPE than in HDPE. These cracks were decreased with increasing the amount

of HDPE in the blend composition. This once again indicates that degradation was

decreased with increasing the amount of HDPE in the blend composition.

73


Fig. 3. Optical micrographs of LDPE, HDPE and their blends after exposure to UV

radiation.

Gathering the findings of this study with previous ones (reference 23) could be useful in

many ways:

- Blending composition could be used as indicator to predicate the final properties and

suitable application of the final LDPE/HDPE blend.

- UV stability of the LDPE/HDPE blends depends on its chemical composition. For

example, blends-rich with HDPE provide better resistance to UV radiation, while

blends-rich with LDPE can be more eco-friendly and posses more degradability. This

would enable industrial and users to identify and select appropriate blends for specific

environments, particularly where durability issues are of significance.

- Resistance of LDPE to UV degradation could be improved by blending with HDPE.

This would enable industrial and companies to identify and select appropriate

LDPE/HDPE blends to replace LDPE for certain outdoor applications, particularly

where the exposure to UV radiation issue are of significant.

- The desired properties for the final LDPE/HDPE blend to be used in suitable

application could be predicated based on the composition. For example, the resistance

to UV degradation and overall mechanical properties gives the blend with the

composition of LDPE (60) / HDPE (40) considerable attention to be used in outdoor

100 µm 100 µm 100 µm

100 µm 100 µm 100 µm

LDPE 20% LDPE 40% LDPE

HDPE 80% LDPE 60% LDPE

74


pplications. Blend (e.g. LDPE (80) / HDPE (20)) possess a light weight and good

toughness which may be used for creating a wide range of goods that include

household plastic products, automotive interior and exterior components and a

number of biomedical devices. Blends-rich with LDPE can replace LDPE to make

films which suitable for a host of applications, such as mulching, packaging of

consumer goods, and industrial products such as fertilizers. On the other hand, blends-

rich with HDPE can replace HDPE in certain applications such as manufacture of

heavy duty films for fertilizers, planting and merchandise bags and containers.

Conclusion

The effects of blending composition on the UV stability of polymer blend comprising

different grades of PEs were investigated. This investigation was accomplished by

studying the susceptibility of LDPE/HDPE blends with varying ratio (80/20, 60/40,

40/60, and 20/80) to UV degradation using accelerated weathering test. After weathering

test, FTIR results indicated the formation of hydrophilic groups such as carbonyl, vinyl,

and hydroxyl in the LDPE, HDPE and their blends. CI was increased after weathering

test for LDPE, HDPE and their blends, confirming the formation of the hydrophilic

groups. The formation of the hydrophilic groups caused reduction in the contact angle

values and wettability changes for LDPE, HDPE and their blends. The optical

microscopic observation results showed visual evidence of surface and morphological

changes after weathering test for all the polymers and blends. It is very important to

conclude here that blending composition plays substantial role in defining the

degradability of the blend. The susceptibility of LDPE/HDPE blends to UV degradation

appeared to decrease with increasing the amount of HDPE in the blend composition.

In our previous work, it was reported that the mechanical properties such as tensile

strength and hardness showed to increase with increasing the amount of HDPE in the

blend composition. In line with previous study, and based on the results obtained in this

work, it is important to conclude here that the resistance of LDPE to UV degradation

could be improved by blending with HDPE without substantial loss in its properties.

Moreover, blend composition can be optimized to meet specific end use property

requirements. In other words, blending composition can be used as indicator to predicate

the final properties and suitable application of the final LDPE/HDPE blend.

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79


Sobolev Spaces in Metric Spaces

Zohra Farnana

Department of Mathematics, Faculty of Education, University of Tripoli

[email protected]

Abstract

We study Sobolev type spaces (called Newtonian spaces) in metric measure spaces equipped

with a doubling measure and supporting a 𝑝 −Poincaré inequality. The Sobolev spaces are

defined using the minimal upper gradient which is a substitute of the modulus of the usual

gradient. We show that they are the right extension of the usual Sobolev spaces in 𝑅𝑛. In

particular Newtonian functions are quasicontinuous and that they are absolutely continues on

almost every curve. Moreover, Newtonian functions are continuous on the complement of

small sets.

Keywords: Newtonian functions; doubling measure; metric space; nonlinear; Sobelev spaces;

Poincaré inequality.

المستخلصفي هذا البحث نقوم بدراسة فضاءات نيوتن وهي تعميم لفضاءات سوبوليف من الفضاءات الاقليدية الى الفضاءات المترية التي تحقق بعض الشروط الاساسية لهذا التعميم. هذه الفضاءات تبنى على استبدال القيمة المطلقة لتدرج الدالة بدالة

تداد الصحيح حيث تجعل الفضاءات تتطابق عند الرجوع الى الفضاءات والتي تكون الام upper gradientجديدة تسمى الاقليدية. كذلك نستنتج ان فضاءات نيوتن تحتفظ بمعظم الخواص الاساسية في هذا التعميم.

1. Introduction

Let 1 < 𝑝 < ∞ and X = (𝑋, 𝑑, µ) be a complete metric spaces endowed with a metric

𝑑 and a positive complete Borel measure µ which is doubling, i.e. there exists a constant

C > 0 such that for all balls 𝐵 = 𝐵(𝑥, 𝑟) ∶= 𝑦 ∈ 𝑋: 𝑑(𝑥, 𝑦) < 𝑟 in X we have

0 < µ(2𝐵) ≤ 𝐶 µ(𝐵) < ∞,

where 2𝐵 = 𝐵(𝑥, 2𝑟).


81

Zohra Farnana

In a metric space the gradient has no obvious meaning as in domains in 𝑹𝒏. Therefore

the concept of an upper gradient was introduced in Heinonen– Koskela [1] as a substitute

of the usual gradient, based on the following observation: It is well known from the

fundamental theorem of calculus that, for every 𝑥, 𝑦 ∈ 𝐑n and smooth function u on 𝑹𝒏,

on the line segment [𝑥, 𝑦] we have

|𝑢(𝑦) − 𝑢(𝑥)| ≤ ∫ |∇𝑢| 𝑑𝑠

[𝑥,𝑦]

In fact, for every rectifiable curve 𝛾 with end points 𝑥 and 𝑦 we have

|𝑢(𝑦) − 𝑢(𝑥)| ≤ ∫|∇𝑢|𝑑𝑠

γ

(1)

Similarly, a nonnegative Borel function 𝑔 is an upper gradient of 𝑢 if (1) holds, for all

rectifiable curves 𝛾, when ∇𝑢 is replaced by 𝑔. It has many useful properties similar to

those of the usual gradient. This makes the variational approach of the Dirichlet problem

available in metric spaces and Sobolev spaces can then be extended to metric spaces.

There are several notions of Sobolev spaces in metric spaces; see for example Cheeger

[2], Hajłasz [3] and Shanmugalingam [4-5]. The definitions in these references are

different but by [4] they give the same Sobolev spaces, under mild assumption. We shall

follow the definition of Shnmugalingam [4], where the Sobolev space 𝑁1.𝑝(𝑋) (called

Newtonian space) was defined as the collection of 𝑝–integrable functions with 𝑝–

integrable upper gradients.

This paper is organized as follows. In Section 2, we present the upper gradient as

introduced in Heinonen–Koskela [1], and use an equivalent definition, of Newtonian

spaces, to the one used in Shanmugalingam [4]. Moreover, we give some of the most

useful property of Newtonian functions. In Section 3, we consider the Newtonian spaces

in a subsets of 𝑋 (with the restrictions of 𝑑 and µ) as a metric spaces in their own right.

We also define the Newtonian space with zero boundary values 𝑁01,𝑝(𝑋) which makes it

possible to compare boundary values of Newtonian functions. Under rather mild

assumptions on 𝑋 it has been shown that Lipschitz functions with compact support are

dense in 𝑁01,𝑝(𝑋) .

In Section 4, we study the Newtonian spaces in the Euclidean setting and show that they

are the right generalization of the usual Sobolev spaces, i.e. both spaces coincide, in the

sense that every 𝑢 ∈ 𝑁1,𝑝(𝑹𝑛) belongs to 𝑊1,𝑝 (𝑹𝑛)and every 𝑢 ∈ 𝑊 1,𝑝 (𝑹𝑛)has a

representative in the Newtonian space 𝑵1,𝑝(𝑹𝑛) which is quasicontinuous. This is a

Luzin type phenomenon, which means that a Sobolev function is continuous on the

complement of a small set. In this setting the removed set has small capacity. We also

give a simple example in the plane which shows that the function 𝜒𝑅 ∈ 𝑊 1,𝑝 (𝑹2) and

81


𝜒𝑅 ∉ 𝑁 1,𝑝(𝑅2). But, as the real line has two-dimensional Lebesgue measure

zero, χR = 0 a.e. in 𝑹2 and clearly 0 ∈ 𝑁 1,𝑝(𝑹2).

2. Upper gradients and Newtonian Spaces

The first order Sobolev spaces in 𝑹𝑛 are defined as follows: For 1 < 𝑝 < ∞ and 𝑓 ∈

𝑳𝑝(𝑹𝑛) we define

∥ 𝑓 ∥𝑊1,𝑝𝑝 (𝑹𝑛) = ∫ (|𝑓|𝑝 + |∇𝑓|𝑝) 𝑑𝑥

𝑹𝑛,

where the ∇𝑓 is the weak gradient of 𝑓. 𝑊1,𝑝(𝑹𝑛) is given by

𝑊1,𝑝(𝑹𝑛) = 𝑓: ∥ 𝑓 ∥𝑊1,𝑝𝑝 (𝑹𝒏) < ∞

As we see to define the 𝑊1,𝑝(𝑹𝒏) one uses the gradient i.e. the directional derivative.

In metric spaces we can not talk about directions. However we do not really use the vector

∇𝑓 , only the scalar |∇𝑓| is used. For |∇𝑓| there is a possible counter part in metric spaces

called upper and has been introduced by Heinnonen–Koskela [1].

In this section we introduce the upper gradient as a substitute of the usual gradient.

Definition 2.1

A nonnegative Borel function g on 𝑋 is said to be an upper gradient of an extended real–

valued function 𝑓 on 𝑋 if for all rectifiable curve 𝛾 ∶ [0, 𝑙𝛾] → 𝑋 parametrized by the

arc length 𝑑𝑠, we have

|𝑓(𝛾(0)) − 𝑓(𝛾(𝑙𝛾))| ≤ ∫ 𝑔 𝑑𝑠𝛾

(2)

whenever both 𝑓 (𝛾(0)) 𝑎𝑛𝑑 𝑓 (𝛾(𝑙𝛾)) are finite, and ∫ 𝑔𝛾

𝑑𝑠 = ∞ otherwise. If 𝑔 is a

nonnegative measurable function on 𝑋 and if (2) holds for 𝑝 −almost every curve then 𝑔

is a 𝑝 −weak upper gradient of 𝑓. The upper gradient in not unique. In particular, from

(2) every Borel function greater than 𝑔 will be another upper gradient of 𝑓. Moreover,

the operation of taking an upper gradient is not linear. However, we have the following

useful property.

Lemma 2.2

If 𝑎, 𝑏 ∈ 𝑹 and 𝑔1, 𝑔2 are upper gradients of 𝑢1, 𝑢2, respectively. Then |𝑎|𝑔1 + |𝑏|𝑔2 is an upper gradient of 𝑎𝑢1 + 𝑏𝑢2. We shall need the following lemma, which gives a nontrivial example of upper gradient,

see Björn–Björn [6], Corollary 1.15.

82

Zohra Farnana

Lemma 2.3

If 𝑋 = 𝑹𝑛 and 𝑓 ∈ 𝐶1(𝑹𝑛), then |∇𝑓| is an upper gradient of 𝑓.

By saying that (2) holds for 𝑝–almost every curve we mean that it fails only for a curve

family with zero 𝑝–modulus.

Definition 2.4

Let 𝛤 be a family of curve on 𝑋. Then we define the 𝑝 −modulus of 𝛤 by

𝑀𝑜𝑑𝑝(Γ) = inf ∫ 𝜌𝑋

𝑑µ, (3)

where the infimum is taken over all nonnegative Borel functions ρ such that ∫ 𝜌𝛾

≥ 1

for all 𝛾 ∈ 𝛤.

If 𝑓 has an upper gradient in 𝑳𝑝(𝑋), then it has a minimal 𝑝–weak upper gradient 𝑔𝑓 ∈

𝑳𝑝(𝑋) in the sense that for every 𝑝–weak upper gradient 𝑔 ∈ 𝑳𝑝(𝑋) of 𝑓, we have, 𝑔𝑓 ≤

𝑔 a.e. see Corollary 3.7 in Shanmugalingam [5].

Proposition 2.5 (Proposition 1.37 in [6]) 𝑀𝑜𝑑(Γ) = 0 if and only if there is a nonnegative Borel function 𝜌 ∈ 𝑳𝑝(𝑋) such that

∫ 𝜌 𝑑𝑠 = ∞.𝛾

In Shanmugalingam [4], upper gradients have been used to define Sobolev type spaces

on metric spaces. We will use the following equivalent definition.

Definition 2.6

Let 𝑢 ∈ 𝑳𝑝(𝑋), then we define

∥ 𝑢 ∥𝑁1,𝑝(𝑋)= (∫ |𝑢|𝑝 𝑑𝜇 + ∫ 𝑔𝑢𝑝 𝑑𝜇

𝑋𝑋

)

1/𝑝

(4)

where the 𝑔𝑢 is the minimal 𝑝—weak upper gradient of 𝑢. The Newtonian space on 𝑋 is

the quotient space

𝑁1,𝑝(𝑋) = 𝑢: ∥ 𝑢 ∥𝑁1,𝑝 (𝑋)< ∞/~,

where 𝑢~𝑣 if and only if ∥ 𝑢 − 𝑣 ∥𝑁1,𝑝(𝑋) = 0.

We also have the following lemma about minimal 𝑝–weak upper gradients, see Björn–

Björn [7], Corollary 3.4.

Lemma 2.7

If 𝑢, 𝑣 ∈ 𝑁1,𝑝 (𝑋), then 𝑔𝑢= 𝑔𝑣 a.e. on 𝑥 ∈ 𝑋: 𝑢(𝑥) = 𝑣(𝑥). Moreover, if 𝑐 ∈𝑹 is a constant, then 𝑔𝑢 = 0 a.e. on 𝑥 ∈ 𝑋: 𝑢(𝑥) = 𝑐.

83


Theorem 2.8 (Theorem 1.56 in [6])

If 𝑢 ∈ 𝑁 1,𝑝(𝑋), then 𝑢 ∈ 𝐴𝐶𝐶𝑝(𝑋), i.e. 𝑢 is absolutely continuous on 𝑝– 𝑎. 𝑒. curve in

the sense that 𝑢 ∘ 𝛾 ∶ [0, 𝑙𝛾] → 𝑹 is absolutely continuous for 𝑝–a.e. curve in 𝛾 in 𝑋.

Lemma 2.9 (Lemma 2.14 in [6]) Assume that 𝑢 ∈ 𝐴𝐶𝐶𝑝(𝑋) and that 𝑔 ∈ 𝐋p(X) is a 𝑝–

weak upper gradient of 𝑢 then for 𝑝—a.e. curve 𝛾 ∶ [0, lγ] ⟶ X we have

|(𝑢 ∘ γ)′(t)| ≤ 𝑔(γ(t)) (5)

for a.e. 𝑡 ∈ [0, 𝑙𝛾]. Conversely, if 𝑔 ≥ 0 is measurable, 𝑢 ∈ 𝐴𝐶𝐶𝑝(𝑋) and (5) holds for

𝑝–a.e. curve 𝛾: [0, 𝑙𝛾] → X, then 𝑔 is a 𝑝–weak upper gradient of 𝑢.

Theorem 2.10 [6] The space 𝑁1,𝑝(𝑋) is a linear normed space.

Proof. That the 𝑁1,𝑝(𝑋) is a vector space follows directly from Lemma 2.2. The only

diff iculty is to proof the triangle inequality. To prove this let 𝑢, 𝑣 ∈ 𝑁1,𝑝(X) and ε > 0 be

arbitrary. Find upper gradients 𝑔, 𝑔′ ∈ 𝐿𝑝(𝑋) of 𝑢 and 𝑣, respectively, so that

(∥ 𝑢 ∥𝐿𝑝(𝑋)𝑝 +∥ 𝑔 ∥𝐿𝑝(𝑋)

𝑝 )

1𝑝≤∥ 𝑢 ∥𝑁1,𝑝(𝑋)+ 𝜀

(6)

(∥ 𝑣 ∥𝐿𝑝(𝑋)𝑝 +∥ 𝑔′ ∥𝐿𝑝(𝑋)

𝑝 )1/𝑝

≤∥ 𝑣 ∥𝑁1,𝑝(𝑋)+ 𝜀

We know that 𝑔 + 𝑔′ is an upper gradient of 𝑢 + 𝑣. Now, note that the left-hand sides

of (6) are the 𝐿𝑝-norms (on 𝑹2) of

(∥ 𝑢 ∥𝐿𝑝(𝑋), ∥ 𝑔 ∥𝐿𝑝(𝑋)) and (∥ 𝑣 ∥𝐿𝑝(𝑋), ∥ 𝑔′ ∥𝐿𝑝(𝑋)),

respectively. Similarly,

∥ 𝑢 + 𝑣 ∥𝑁1,𝑝(𝑋)

𝑝≤ (∥ 𝑢 + 𝑣 ∥𝐿𝑝(𝑋)

𝑝 +∥ 𝑔 + 𝑔′ ∥𝐿𝑝(𝑋)𝑝 )

1/𝑝

≤ ((∥ 𝑢 ∥𝐿𝑝(𝑋)+∥ 𝑣 ∥𝐿𝑝(𝑋))𝑝+ (∥ 𝑔 ∥𝐿𝑝(𝑋)+∥ 𝑔′ ∥𝐿𝑝(𝑋))

𝑝

)1/𝑝

,

which is the 𝑳𝑝 −norm of

(∥ 𝑢 ∥𝑳𝑝(𝑋)+∥ 𝑣 ∥𝑳𝑝(𝑋), ∥ 𝑔 ∥𝑳𝑝(𝑋)+∥ 𝑔′ ∥𝑳𝑝(𝑋) ).

The triangle inequality of the 𝐿𝑝 −norm now implies that

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Zohra Farnana

∥ 𝑢 + 𝑣 ∥𝑁1,𝑝(𝑋)

𝑝≤ (∥ 𝑢 ∥𝐿𝑝(𝑋)

𝑝 +∥ 𝑔 ∥𝐿𝑝(𝑋)𝑝 )

1/𝑝

+ (∥ 𝑣 ∥𝐿𝑝(𝑋)𝑝 +∥ 𝑔′ ∥𝐿𝑝(𝑋)

𝑝 )1/𝑝

≤∥ 𝑢 ∥𝑁1,𝑝(𝑋)

𝑝+ 𝜀 +∥ 𝑣 ∥

𝑁1,𝑝(𝑋)

𝑝+ 𝜀

And letting 𝜀 → 0 proves the triangle inequality for the ∥∙∥𝑁1,𝑝(𝑋).

In Shanmugalingam [4], Theorem 3.7 and p. 249 it has been shown that the space

𝑁1,𝑝(𝑋) is a Banach space and lattice.

Theorem 2.11

The space 𝑁 1,𝑝(𝑋) is a lattice, i.e. if 𝑢, 𝑣 ∈ 𝑁1,𝑝(𝑋), then 𝑚𝑎𝑥𝑢, 𝑣, 𝑚𝑖𝑛𝑢, 𝑣 ∈ 𝑁1,𝑝(𝑋).

Definition 2.12

The Capacity of a set 𝐸 ⊂ 𝑋 is defined by

𝐶𝑝(𝐸) = inf𝑢∥ 𝑢 ∥𝑁1,𝑝(𝑋)

where the infimnm is taken over all 𝑢 ∈ 𝑁1,𝑝(𝑋) such that 𝑢 ≥ 1 on 𝐸. We say that a property holds quasieverywhere (q.e.) in 𝑋, if it holds everywhere except

a set of capacity zero. Newtonian functions are well defined up to sets of capacity zero,

i.e. if 𝑢, 𝑣 ∈ 𝑁1,𝑝(𝑋) then 𝑢 ~ 𝑣 if and only if 𝑢 = 𝑣 q.e. Moreover, Corollary 3.3 in

Shanmugalingam [4] shows that if 𝑢, 𝑣 ∈ 𝑁1,𝑝(𝑋) and 𝑢 = 𝑣 a.e., then 𝑢 = 𝑣 q.e.

The following proposition gives the relation between small set and small curve family.

Proposition 2.13

Let 𝐸 ⊂ X. Then 𝐶𝑝(𝐸) = 0 if and only if µ(𝐸) = Mod𝑝(ΓE) = 0

Where

ΓE = γ ∈ Γ(X): γ−1(E) ≠ ϕ.

We also have the following property for Newtonian functions, see Theorem 1.1 in

Björn–Björn–Shanmugalingam [10].

Lemma 2.14

Every function 𝑢 ∈ 𝑁 1,𝑝(𝑋) is quasicontinuous, i.e., for every 𝜀 > 0 there is an open

set 𝐺 ⊂ 𝑋 such that 𝐶𝑝(𝐺) < 𝜀 and 𝑢|𝑋 ∖𝐺 is continuous.

𝟑.𝑵𝟏,𝒑 (Ω) and 𝑵𝟎𝟏,𝒑(Ω)

For 𝐸 ⊂ 𝑋 we define the space 𝑁1,𝑝 (𝐸) with respect to the restrictions of the metric

𝑑 and the measure µ to 𝐸. A function 𝑓 ∈ 𝑁1,𝑝(𝑋) clearly has a restriction 𝑓| 𝐸 which

85


belongs to the 𝑁1,𝑝(𝐸) and any 𝑝 −weak upper gradient of it remains a 𝑝–weak upper

gradient when restricted. However, the restriction of a minimal 𝑝–weak upper gradient

is not always minimal. If 𝐸 = Ω is open then the restriction of a minimal 𝑝–weak upper

gradient remains minimal.

Lemma 3.1

Assume that 𝑓 ∈ 𝑁1,𝑝(𝑋) with a minimal 𝑝–weak upper gradient 𝑔𝑓 (with respect to

𝑋). Then 𝑔𝑓|Ω is a minimal 𝑝–weak upper gradient of 𝑓 with respect to Ω.

From now on we assume that X supports a 𝑝–Poincaré inequality, i.e. there exist

constants 𝐶 > 0 and 𝜆 ≥ 1 such that for all balls 𝐵(𝑧, 𝑟) in 𝑋, all integrable functions 𝑢

on 𝑋 and all upper gradients 𝑔 of 𝑢 we have

1

µ(B)∫ |𝑢 − 𝑢B(z,r)|𝐵(𝑧,𝑟)

𝑑𝜇 ≤ 𝐶 𝑟 (1

𝜇(𝐵)∫ 𝑔𝑝 𝑑𝜇𝐵(𝑧,𝜆𝑟)

)

1/𝑝

,

where 𝑢𝐵(𝑧,𝑟) ∶= 1

𝜇(𝐵)∫ 𝑢𝐵(𝑧,𝑟)

𝑑µ.

To be able to compare the boundary values of Newtonian functions we need to define a

Newtonian space with zero boundary values outside of Ω as follows.

Definition 3.2

Let Ω ⊂ 𝑋 be open, then the Newtonian space with zero boundary values 𝑁01,𝑝(Ω) is

defined by

𝑁01,𝑝(Ω) = 𝑓|Ω ∶ 𝑓 ∈ 𝑋 𝑎𝑛𝑑 𝑓 = 0 𝑞. 𝑒. 𝑖𝑛 𝑋 \ Ω.

Under our assumptions, Lipschitz functions with compact support are dense in

𝑁01,𝑝(Ω), see Shanmugalingam [5]. Moreover, the proof of this result in [6] shows that

if 0 ≤ 𝑢 ∈ 𝑁01,𝑝(Ω), then we can choose the Lipschitz approximation to be nonnegative.

The following Poincaré type inequality is useful, for a proof, see e.g Kinnunen–

Shanmugalingam [9], Lemma 2.1.

Lemma 3.3

Assume that Ω ⊂ 𝑋 is a nonempty bounded open set with Cp(X \ Ω) > 0. There exists

a constant C > 0 such that for all 𝑢 ∈ 𝑁0 1,𝑝(Ω) we have

∫ |𝑢|𝑝 𝑑𝜇 ≤ 𝐶∫ 𝑔𝑢𝑝

Ω𝛺

𝑑𝜇

86

Zohra Farnana

The following lemma is useful for proving that a function belongs to the 𝑁01,𝑝(Ω), see

Lemma 5.3 in Björn–Björn [8].

Lemma 3.4

Let 𝑢 ∈ 𝑁1,𝑝 (Ω) be such that 𝑣 ≤ 𝑢 ≤ 𝑤 q.e. in Ω for some 𝑣,𝑤 ∈ 𝑁0

1,𝑝(Ω).

Then 𝑢 ∈ 𝑁01,𝑝(Ω).

Proposition 3.5 (Proposition 2.38 in [6])

For 𝑁01,𝑝(Ω) we have

∥ 𝑓 ∥𝑁1,𝑝(𝑋) = ∥ 𝑓 ∥𝑁 1,𝑝(Ω).

Proof. We may assume that 𝑓 = 0 out side of Ω. Let gf be a minimal 𝑝–weak upper

gradient of 𝑓 with respect to 𝑋. By Lemma 3.1, 𝑔𝑓|Ω is a minimal 𝑝–weak upper gradient

of f with respect to Ω. On the other hand by Lemma 2.7 𝑔𝑓 = 0 a.e. outside of Ω. Hence

∥ 𝑓 ∥𝑁1,𝑝 (𝑋)

𝑝= ∥ 𝑓 ∥𝐿𝑝(𝑋)

𝑝 +∥ 𝑔𝑓 ∥𝐿𝑝(𝑋)𝑝

=∥ 𝑓 ∥𝐿𝑝(Ω)𝑝 +∥ 𝑔𝑓 ∥𝐿𝑝(Ω)

𝑝 =∥ 𝑓 ∥𝑁1,𝑝 (Ω)

𝑝.

4. The Newtonian space 𝑵 𝟏,𝒑(Ω) in the Euclidean spaces

In this section we see that, when restricted to 𝑹𝑛, the Newtonian space is the refined

Sobolev space 𝑊1,𝑝(𝑹𝑛), as defined in Chapter 4 in Heinonen– Kilpeläinen–Martio [11].

Lemma 4.1

Let Γ be a collection of curves in 𝑹𝑛. If 𝑀𝑜𝑑𝑝Γ = 0, then a.e. (with respect to the

(𝑛 − 1) −dimensional Lebesgue measure) line parallel to the 𝑥1-axis contains no curve

from Γ. The following Theorem was obtained by Shanmugalingam [4], we use the proof in [6].

Theorem 4.2

If Ω ⊂ 𝑅𝑛, then 𝑁 1,𝑝(Ω) = 𝑊1,𝑝 (Ω), as a Banach spaces, with equivalent norms.

More precisely, if 𝑢 ∈ 𝑁1,𝑝(Ω), then 𝑢 ∈ 𝑊1,𝑝(Ω) and conversely, for every 𝑢 ∈

𝑊1,𝑝(Ω) then there exists ∈ 𝑁1,𝑝(Ω)such that = 𝑢 a.e., in Ω. Moreover, if 𝑢 ∈

𝑊1,𝑝(Ω) is quasicontinuous, then 𝑢 ∈ 𝑁1,𝑝(Ω).

Proof. Let 𝑢 ∈ 𝑁1,𝑝(Ω) with a 𝑝 −weak upper gradient 𝑔 ∈ 𝐿𝑃(Ω). By Lemma 2.9 and

Proposition 2.5, 𝑢 ∈ 𝐴𝐶𝐶𝑝(Ω) and ∫ 𝑔 𝑑𝑠𝛾

< ∞ for 𝑝– 𝑎. 𝑒. curve 𝛾 in Ω. Lemma 2.8

and Lemma 4.1 now imply that 𝑢 is absolutely continuous on a.e. (with respect to the (𝑛 −

87


1)−dimensional Lebesgue measure) line segment 𝑙 in Ω parallel to the 𝑥1 axis and for a.e. 𝑥 ∈ 𝑙,

|𝜕𝑢(𝑥)

𝜕𝑥1| ≤ 𝑔(𝑥).

The Fubini theorem then shows that |𝜕𝑢/𝜕𝑥1| ≤ 𝑔 a.e. in Ω and hence 𝜕𝑢/𝜕𝑥1 ∈𝑳𝑝(Ω) ⊂ 𝑳𝑙𝑜𝑐

1 (Ω). The absolute continuity of 𝑢 at 𝑙 implies that 𝜕𝑢/𝜕𝑥1 is the one—

dimensional distributional of 𝑢 in 𝑙.

Another application of the Fubini theorem to the integrals

∫𝜕𝜑(𝑥)

𝜕𝑥1Ω

𝑢(𝑥) 𝑑𝑥 = −∫ 𝜑(𝑥)Ω

𝜕𝑢(𝑥)

𝜕𝑥1 𝑑𝑥

with 𝜑 ∈ 𝐶0∞(Ω), shows that 𝜕𝑢/𝜕𝑥1 is the distributional derivative of 𝑢 in Ω. The other

partial derivative are handled similarly. Hence 𝑢 ∈ 𝑊𝑙𝑜𝑐1,𝑝(Ω) and

∥ 𝑢 ∥𝑊1,𝑝(Ω)≤ 𝑛 ∥ 𝑢 ∥𝑁1,𝑝(Ω).

Conversely, let 𝑢 ∈ 𝑊1,𝑝(Ω). By e.g. Theorem 2.3.2 in Ziemer [12] there exist 𝑢𝑗 ∈

𝐶∞(Ω) such that 𝑢𝑗 → 𝑢 in 𝑊1,𝑝(Ω), as 𝑗 → ∞. Lemma 2.3 shows that |∇𝑢𝑗| are

upper gradients of 𝑢𝑗 . Hence 𝑢𝑗 ∈ 𝑁1,𝑝(Ω) and ∥ 𝑢𝑗 ∥𝑁1,𝑝(Ω)≤∥ 𝑢𝑗 ∥𝑊1,𝑝(Ω), 𝑗 = 1,2, ….

Proposition 2.3 in [6] provides us with a function ∈ 𝑁1,𝑝(Ω) such that = 𝑢 a.e.

and |∇𝑢| is a 𝑝—weak upper gradient of . Moreover, ∥ ∥𝑁1,𝑝(Ω)≤∥ 𝑢 ∥𝑊1,𝑝(Ω). Thus

𝑢 ∈ 𝑁1,𝑝(Ω). If 𝑢 ∈ 𝑊1,𝑝(Ω) is quasicontinuous, then = 𝑢 q.e., by Proposition 5.23 in [6], and

hence 𝑢 ∈ 𝑁1,𝑝(Ω).

Proposition 4.3

Let Ω ⊂ 𝑹𝑛 and let 𝑢 be locally Lipschitz in Ω. Then 𝑔𝑢 = |∇𝑢| a.e., in Ω.

Corollary 4.4

For every 𝑢 ∈ 𝑁1,𝑝(Ω), we have

∥ 𝑢 ∥𝑁1,𝑝(Ω)=∥ 𝑢 ∥𝑊1,𝑝(Ω).

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[3] Hajłasz. P. (1996) Sobolev spaces on an arbitrary metric spaces, Potential Anal 5,

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89


البوزونات نموذج باستخدام شفعية–الشفعية 𝑬𝒓𝟏𝟔𝟐−𝟏𝟓𝟔 نظائر خصائص دراسة IBM-2 المتفاعلة

،2d، دلنده محمد ناصفc2، عياد الهادي الزوام7b، سعاد محمد بوقرين7aنجاة سالم الشفتري

e2محمد القاضي الصادق و

ليبيا-طرابلس ،الهندسية للتقنيات العالي المعهد ،العام القسم2 ليبيا -طرابلس ،طرابلس جامعة ،العلوم كلية ،الفيزياء قسم2

[email protected]; [email protected]; [email protected]; [email protected]; [email protected]

المستخلصباستخدام 717-701شفعية ذات الاعداد الكتلية من -تم في هذا البحث حساب مستويات الطاقة لبعض نظائر الإربيوم الشفعية

كما تم ايجاد عزم القصور الذاتي ومربع طاقة الفوتون المنبعث للقيم المعملية والمحسوبة IBM-2نموذج المفاعلة البوزونية +𝑬𝟒𝟏)ورسم العلاقة البيانية بينهما وكذلك ايجاد النسبة 𝑬𝟐𝟏+⁄ وأيضا (U(5), O(6), SU(3))ومقارنتها مع التحديدات الثلاث (

، وتمت مقارنة جميع E-GOSلمذكورة ومقارنتها بالمنحنيات المعيارية ا Erلنظائر 𝑰كدالة في البرم (𝑬𝜸/𝑰)رسم منحنيات yrast)على النطاق الطبيعي E-GOSالقيم المحسوبة مع القيم المعملية وأظهرت النتائج توافقا جيدا بينهما، وبتطبيق طريقة

band) تبين ان للنظيرين ،Er158Er, 156 عند قيم برمية منخفضة خصائص غاما الغير مستقرة وبارتفاع قيم البرم انتقلت هذه خصائص دورانية. Er 162 Er,160الخصائص الى الحالة الدورانية، بينما أظهرت حالة النظيرين

منحنى ;شفعية-يةالنوى الشفع (yrast band);النطاق الطبيعي ;المفاعلة البوزونية ;الكلمات الدالة: الزخوم الزاوية

E-GOS ;.نظائر الاربيوم

Abstract Interacting Boson model-2 was used to calculate the energy levels of some of the even-even

erbium isotopes with mass numbers 156-162. The extracted moment of inertia has been

plotted versus the square of energy of the emitted photon for the experimental and computed

values. The ratio of the excitation energies of the first 41+ over the first 21

+, [𝑅 =(𝐸41+ 𝐸21+)⁄ ], is also calculated, and then compared with the three limits (SU (3), U

(5) and O (6)).


91

محمد القاضي الصادق و نجاة سالم الشفتري، سعاد محمد بوقرين، عياد الهادي الزوام، دلنده محمد ناصف

In addition, the E-GOS curve as a function of the spin is presented. All calculated

values are compared with the available experimental data and show reasonable

agreement. Whereas, the two isotopes 156Er and 158Er at low spin values had unstable

gamma characteristics and with high spin values, these properties transferred to the

rotational state, while the tow isotopes 160Er and 162Er showed a rotational behavior.

Keywords: Angular momentum; E-GOS curve; Erbium Isotopes; even-even nuclei;

Interacting Boson Model-2; Yrast band.

المقـدمة

ي عتبر الإنتقال الطوري تبعا للعدد النيوكليوني والبرم من أحد أهم الموضوعات في أبحاث البنية النووية، ويرتبط هذا الإنتقال إرتباطا وثيقا بالآليات التي تولد من خلالها النوى الذرية زخما زاويا. في الآونة الأخيرة، تم تأسيس العديد

𝛾بتراكيب الحزم الجماعية المختلفة بشكل جيد عن طريق التحليل الطيفي لإشعاع من الظواهر المرصودة المرتبطة . ت ظهر هذه التركيبات المتميزة توليد الزخم الزاوي بطرق مختلفة، ويمكن أن تشارك الخصائص [1]داخل النطاق

كل عام عن طريق الحركة . في النوى حيث تتشكل الحالة المثارة بش[2]المختلفة في نمط واحد من الحركة الجماعية الجماعية وانكسار الزوج النيوكليوني، يتم إعادة ترتيب م تقنة لعدد قليل فقط من النيوكليونات بين المدارات القريبة من

إن دراسة الإستثارات المجهرية لأنظمة النيوكليون سطح فيرمي الذي يمكن ان ينتج في أنماط جماعية مختلفة تماما.قالات بين أنماط الإثارة المختلفة يمكن أن تلقي الضوء على طبيعة الحالات الواقعة بالقرب من سطح المتعددة والإنت

. [3]فيرمي، مما يسمح باستنتاج شكل المجال المتوسط النووي )طاقة غاما على البرم(، لتمييز الإثارات E-Gosطريقة بسيطة تسمى منحنى [4]وآخرون [Regan]إقترح ريغان

(Yrast)النطاق الطبيعي التي تؤدي إلى التذبذب أو الدوران. تم تطبيق هذه الوصفة على سلاسل الجماعية[01+, 21

+, 41+, 61

+, … . . شفعية، وقد تم العثور على تطور واضح في التركيب من الإهتزاز - في النوى الشفعية [ إلى الدوران مع زيادة البرم.

طاق النتنتمي إلى منطقة بالغة التشوه، عليه يمكن إستنتاج أن A<190>150إن معظم النوى في منطقة الكتل ت ظهر بنية دورانية. ومع ذلك فإن آخر النتائج قدمت دليلا على ظاهرة مثيرة للإهتمام بشكل خاص، وهي الطبيعي

غاما الغير ، وقد تم هنا ملاحظة التطور من تركيب[5]التطور من التركيب الدوراني إلى الاهتزازي كدالة في البرم لنظائر (158-156)شفعية في المنطقة الكتلية - مستقرة إلى التركيب الدوراني، في أطياف الإثارة للنوى الشفعية

الإربيوم.

91

IBM-2 المتفاعلة البوزونات نموذج باستخدام شفعية–الشفعية 𝑬𝒓𝟏𝟔𝟐−𝟏𝟓𝟔 نظائر خصائص دراسة

النظرية

البروتون عن بوزونات النترون لدراسة النوى يميز بوزونات( والذي (IBM-2تم استخدام نموذج المفاعلة البوزونية شفعية، ويأخذ هذا النموذج في الإعتبار المفاعلة بين بوزونات البروتون وبوزونات النترون، ويكون لكل –الشفعية

، وي عطى الشكل d –وتسمى بوزونات الحالة 1برم يساوي ، أو S–منهما إما برم صفري وتسمى بوزونات الحالة بالصورة التالية: [6,7]العام للدالة الهاملتونية في هذا النموذج

(1) 𝐻 = 𝐻𝜋 + 𝐻𝜈 + 𝐻𝜋𝜈 𝐻𝜋𝜈وهاملتونيوم للمفاعلة بينهما ،𝐻𝜈وهاملتونيوم للنترون 𝐻𝜋تون و كما يتضح، يحوي هذا الشكل هاملتونيوم للبر

فة في برنامج حاسوب يسمى ، ت عرف كل دالة هاملتونية بدلالة مجموعة من البارامترات في معادلات رياضية م عرNPBOS [8]،[4].ي ستخدم هذا البرنامج لحساب مستويات الطاقة وبعض الخصائص النووية الاخرى ،

[9]للمتذبذب التوافقي الكمي، بالمعادلة Iلحالات البرم (Yrast)الطبيعي نطاقى طاقات الت عط(2) 𝐸𝐼 = 𝑛ℏ𝜔

𝑛 )عدد الفونونات nحيث =𝐼

2 الطبيعيةبين المستويات عنصر المصفوفة المختزل . يختلفالتردد الزاوي 𝜔و (

𝐼∆ مقدارب = [9]. . وتعطى حالات الطاقة الدورانية بالعلاقة2(3 )𝐸𝐼 = [

ℏ2

2𝐽] 𝐼(𝐼 + 1)

يكون فرق الطاقة الدورانية بين مستويين متتاليين كالتالي: دوراني، وبذلكال ر الذاتيعزم القصو Jحيث (4 )𝐸𝐼 − 𝐸𝐼−2 = 𝐸𝛾 = [

ℏ2

2𝐽] (4𝐼 − 2)

(0) 2𝐽

ℏ2= (4𝐼 − 2)/𝐸𝛾

𝐼و 𝐼طاقة الفونون عند الانتقال بين حالتي البرم )أما − ( فتعطى بالعلاقة: 2(6) ħ𝜔 = 𝐸𝛾 /( √I(𝐼 + 1 − √(𝐼 − 2)(𝐼 − 1) )

𝑅ت عتبر النسبة = 𝐸𝛾(𝐼 → 𝐼 − 2)/𝐼 شكل التماثل الدوراني والاهتزازي المحوري حيث: بين تمييز لطريقة فعالة ل ؛ [4]الاهتزازي في

(0 ) 𝑅 =ħ𝜔

𝐼

𝐼→∞→ 0

:الدوراني فهي وفي(5 ) 𝑅 = (ħ2/2𝐽) (4 −

2

𝐼)𝐼→∞→ 4(ħ2/2𝐽)

𝐼عندما (ħ2/2𝐽)3من 𝑅في التماثل الدوراني المحوري تتراوح قيمة = 𝐼عندما تكون (ħ2/2𝐽)4إلى 2في هذه الورقة البحثية سنقوم بدراسة تركيب وسلوك النوى .[4]نحو الصفر 𝑅كبيرة، بينما في الاهتزازي تتضاءل قيمة

.(E-GOS)الغير مستقرة كدالة في البرم النووي باستخدام غاماالاهتزازية والدورانية و

92


للحالات الثلاثة Iكدالة في البرم (E-GOS) يات نموذجية لطاقة غاما على البرمبرسم منحن [4] ريغانقام U(5))، SU(3)و(O(6) [2] ،[5]، [10]تالية:باستخدام المعادلات ال

U(5)الحالة الاهتزازية

(6 )𝐸𝛾(𝐼→𝐼−2)

I=ℏ𝜔

𝐼

SU (3)الحالة الدورانية

(27 )𝐸𝛾(𝐼 → 𝐼 − 2)/I = ( ħ2 2𝐽)⁄ (4 −

2

𝐼 )

O (6)الغير مستقرة غاماحالة

(22 ) 𝐸𝛾(𝐼→𝐼−2)

I= (

𝐸21+

4) (1 +

2

𝐼)

الحسابات والمناقشة

شفعية -الشفعية Erلبعض نظائر عنصر الإربيوم للنطاق الطبيعي الطاقةمستويات تم في هذا البحث حساب

𝐸𝛾(𝐼→𝐼−2))ورسم عدة منحنيات لـقيم ) NPBOSوذلك باستخدام برنامج I

.Iكدالة في الزخم الزاوي الطبيعي المحسوبة بواسطة نموذج المفاعلة البوزونيةللنطاق ( قيم مستويات الطاقة 4( إلى )2)من الجداول بينت

IBM-2 [13-11] والمعملية ( بوحدةMeVونسبة الخطأ ) ( تبين القيم 8( إلى )5الجداول من )و ، للنظائر المذكورة يبين قيمف( 9الجدول ) أما نظيرطاقة الإنتقال وعزم القصور الذاتي ومربع طاقة الفوتون لكل المعملية والمحسوبة ل

+𝑬𝟒𝟏(والنسبة بين )+𝑬𝟐(طاقة المستوى 𝑬𝟐𝟏+⁄( نظائر للتحديدات الثلاث لEr المذكورة. +𝑬𝟒𝟏)منحنى 2يوضح الشكل 𝑬𝟐𝟏+⁄ هذا المنحنى مؤشرات أولية لخصائص يعطي .كدالة في العدد الكتلي (

الغير مستقرة أي من الحالة SU (3)إلى الطور O (6)سلسلة النظائر قيد الدراسة وتبين أن النظائر تنتقل من الطور عند الانتقال 2(ħ𝜔)كدالة في ( 2𝐽/ℏ2)إلى الحالة الدورانية. ولزيادة المعلومات تم رسم منحنى عزم القصور الذاتي

𝐼)إلى (𝐼)من − .1كما في الشكل (2

93

IBM-2 المتفاعلة البوزونات نموذج باستخدام شفعية–الشفعية 𝑬𝒓𝟏𝟔𝟐−𝟏𝟓𝟔 نظائر خصائص دراسة

MeV. بوحدة𝐸𝑟158مستويات الطاقة للنظير 2.جدول MeV . بوحدة 𝐸𝑟156مستويات الطاقة للنظير 1.جدول Δ (%) Ecal Eexp 𝐽𝜋

7.24- 7.340 7.3440 21+

0.3 7.060 7.0604 41+

2.21 2.310 2.347 61+

2.66 1.920 2.606 81+

2.00 1.050 1.553 101+

7.02- 3.332 3.324 121+

MeV.بوحدة 𝐸𝑟162مستويات الطاقة للنظير .4جدول MeV.بوحدة 𝐸𝑟160ر مستويات الطاقة للنظي .3جدول

Δ (%) Ecal Eexp 𝐽𝜋

7.7 7.215 7.215 21+

7.04 7.350 7.3566 41+

2.06 7.001 7.0500 61+

1.35 2.177 2.116 81+

2.65 2.052 2.052 101+

7.50 1.317 1.347 121+

.المعملية والمحسوبة𝐸𝑟156قيم طاقة الانتقال وعزم القصور الذاتي ومربع طاقة الفوتون للنظير .0 جدول

Cal Exp 𝐽𝑖+ → 𝐽𝑓

+ (ħ𝜔)2 (MeV)2

2J/ħ2 (MeV)-1

𝐸𝛾 (MeV)

(ħ𝜔)2 (MeV)2

2J/ħ2 (MeV)-1

𝐸𝛾 (MeV)

0.020 17.391 0.345 7.717 20.420 0.345 21+ → 01

+ 0.049 31.111 0.450 7.707 37.621 7.403 41

+ → 21+

0.070 41.509 0.530 7.703 47.045 7.043 61+ → 41

+ 0.088 50.420 0.595 7.760 45.450 7.526 81

+ → 61+

0.111 56.972 0.667 7.223 05.357 7.504 101+ → 81

+ 0.138 61.828 0.744 7.225 50.045 7.552 121

+ → 101+

Δ (%) Ecal Eexp 𝐽𝜋 7.7 7.261 7.261 21

+ -1.33 7.034 7.010 41

+ -0.1 7.602 7.607 61

+ 2.52 2.456 2.463 81

+ 1.21 1.715 1.701 101

+ 7.53 1.554 1.557 121

+

Δ (%) Ecal Eexp 𝐽𝜋 7.7 7.271 7.271 21

+ 2.1 7.310 7.316 41

+ 1.0 7.546 7.555 61

+ 3.2 2.751 2.765 81

+ 7.21- 2.574 2.571 101

+ 2.55- 1.172 1.250 121

+

94


.المعملية والمحسوبة𝐸𝑟158قيم طاقة الانتقال وعزم القصور الذاتي ومربع طاقة الفوتون للنظير .5جدول Cal Exp

𝐽𝑖+ → 𝐽𝑓

+ (ħω)2 (MeV)2

2J/ħ2 (MeV)-1

𝐸𝛾 (MeV)

(ħω)2 (MeV)2

2J/ħ2 (MeV)-1

𝐸𝛾 (MeV)

0.006 31.25 0.192 7.775 32.107 7.261 21+ → 01

+ 0.029 40.936 0.342 7.710 42.062 7.330 41

+ → 21+

0.047 50.343 0.437 7.746 46.552 7.443 61+ → 41

+ 0.062 60.241 0.498 7.755 00.352 7.013 81

+ → 61+

0.078 67.979 0.559 7.754 50.537 7.006 101+ → 81

+ 0.101 72.327 0.636 7.763 00.034 7.576 121

+ → 101+

.المعملية والمحسوبة𝐸𝑟160قيم طاقة الانتقال وعزم القصور الذاتي ومربع طاقة الفوتون للنظير .0جدول

)لعلاقة المعيارية لمنحنيات ال 3يمثل شكل

𝐸𝛾

𝐼) (E-GOS) كدالة في 𝐼 لــU(5), O(6), SU(3) 21 للمستوى

عند +( يوضح 4(. أما الشكل )11(، )10(، )9التوالي باستخدام المعادلات )( على MeV) بوحدة (0.100 ,0.300 ,0.500)

)مدى التطابق بين القيم المعملية والمحسوبة لقيمة 𝐸𝛾

𝐼 كدالة في البرم. (

هذين أنكما يتضح من الشكل Gos-E ياتمع منحن Er158و Er156النظيرين يب( مقارنة لمنحن-أ( 0يوضح الشكل 𝐼النظيرين لهما نفس السلوك حيث انهما في المدى من = 𝐼إلى 2 = ولكن عندما O(6)تميل إلى الحالة الغير مستقرة 10

Er621و Er601, أما النظيرين [14]و SU (3) [4]أكبر فإنها تتبع المنحنى الدوراني 𝐼تكون قيم

Cal Exp 𝐽𝑖+ → 𝐽𝑓

+ (ħ𝜔)2 (MeV)2

2J/ħ2 (MeV)-1

𝐸𝛾 (MeV)

(ħ𝜔)2 (MeV)2

2J/ħ2 (MeV)-1

𝐸𝛾 (MeV)

0.003 47.619 0.126 7.773 45.777 7.210 21+ → 01

+ 0.017 53.640 0.261 7.720 01.507 7.150 41

+ → 21+

0.033 60.274 0.365 7.730 05.041 7.305 61+ → 41

+ 0.05 66.964 0.448 7.703 54.003 7.453 81

+ → 61+

0.069 72.243 0.526 7.702 02.416 7.031 101+ → 81

+ 0.088 77.441 0.594 7.754 06.440 7.006 121

+ → 101+

95

IBM-2 المتفاعلة البوزونات نموذج باستخدام شفعية–الشفعية 𝐸𝑟162−156 نظائر خصائص دراسة

ما يماثلان انه نجديات المعيارية منحنالبنفس السلوك أيضا وبمقارنتهما يسلكانفانهما )وبأ ( 5وكما هو ملاحظ من الشكل

. SU (3)المنحنى الدوراني

.المعملية والمحسوبة𝐸𝑟162قيم طاقة الانتقال وعزم القصور الذاتي ومربع طاقة الفوتون للنظير .5جدول Cal Exp

𝐽𝑖+ → 𝐽𝑓

+ (ħ𝜔)2 (MeV)2

2J/ħ2 (MeV)-1

𝐸𝛾 (MeV)

(ħω)2 (MeV)2

2J/ħ2 (MeV)-1

𝐸𝛾

0.002 58.824 0.102 7.777 05.514 7.271 21+ → 01

+ 0.012 62.780 0.223 7.723 52.504 7.110 41

+ → 21+

0.026 67.901 0.324 7.715 50.151 7.330 61+ → 41

+ 0.042 72.639 0.413 7.745 56.050 7.437 81

+ → 61+

0.073 70.111 0.542 7.754 00.766 7.075 101+ → 81

+ 0.089 77.052 0.597 7.706 52.070 7.053 121

+ → 101+

+𝑬𝟒𝟏)والنسبة +𝑬𝟐طاقة المستوى .6جدول 𝑬𝟐𝟏+⁄ .المحسوبة Erللتحديدات الثلاث ولنظائر (

.والتحديدات الثلاث +𝐸4+/𝐸2منحنى .2شكل

𝐸𝑟162 𝐸𝑟160 𝐸𝑟158 𝐸𝑟156 SU (3) O (6) U (5) 7.271 7.215 7.261 7.340 277 377 077 𝑬𝟐+

3.2 3.7 1.05 1.3 3.3 1.0 1.7 (𝑬𝟒𝟏+ 𝑬𝟐𝟏+⁄ )

96

محمد القاضي الصادق و الشفتري، سعاد محمد بوقرين، عياد الهادي الزوام، دلنده محمد ناصفنجاة سالم

.العلاقة بين عزم القصور الذاتي ومربع طاقة الفوتون .1شكل

.النموذجي E-GOSمنحنى .3شكل

97

IBM-2 المتفاعلة البوزونات نموذج باستخدام شفعية–الشفعية 𝐸𝑟162−156 نظائر خصائص دراسة

)القيم المعملية والمحسوبة .4شكل

𝐸𝛾

𝐼 .شفعية-الشفعة Er162-156لنظائر )𝐼(كدالة في (

)أ(

Er158المحسوب للنظير Gos-E. منحنى )أ( 0شكل

.مع المنحنيات المعيارية

)ب(

مع Er 156المحسوب للنظير Gos-E . منحنى)ب( 7شكل

.المعياريةالمنحنيات

98


)أ( )ب( المحسوب للنظير Gos-E . منحنى)ب( 6شكل Er160المحسوب للنظير Gos-E. منحنى )أ( 6شكل

Er162 مع المنحنيات المعيارية .مع المنحنيات المعيارية.

الخلاصة

Er, 156تناولنا في هذا البحث دراسة الخصائص النووية لنظائر الإربيوم كدالة في البرم وقد وجدنا أن النظيرين

Er158 الغير مستقرة وكلما زادت قيم البرم انتقلت الى الحالة الدورانية بينما النظيرين غامالهما خصائص Er,160

Er 162 السلسلة من النظائر تنتقل من الحالة الغير مستقرة الى الحالة لهما خصائص دورانية خالصة أي ان هذه الدورانية.

المراجع

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𝐸𝑟162−156 نظائر خصائص دراسة IBM-2 المتفاعلة البوزونات نموذج باستخدام شفعية–الشفعية

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111


Use of Finite Difference Time Domain (FDTD) Technique to Calculate

Poynting Vector in Free Space with Obstacles

in Computational Domain

Sedig S. Farhat

University of Tripoli, Faculty of Science, Physics Department

Email: [email protected]

Abstract

In this paper, electromagnetic simulations in the two- and three-dimensions

systems are performed by the finite difference time domain (FDTD) technique.

The method can be applied for solving Maxwell’s curl equations numerically to

calculate the Poynting vector distributions when placing the obstacles in the centre

of a domain. Perfect electric conductor (PEC) structures of convenient shapes were

constructed based on the geometric shape of the obstacle such as two parallel strips

and triangle shapes in order to make a comparison between the simulations. The

FDTD method will determine the values of the electric and magnetic field at any

point in space and the grid is terminated with the first-oraer Gerrit Mur’s absorbing

boundary condition (ABC) [1]. The boundary condition can be included in the

calculations to absorb the waves when striking the boundaries. The ABC can affect

the accuracy of the solutions as the calculations results demonstrate that good

numerical performance of the FDTD obtained when utilizing the Mur’s ABC. In

the provided examples, the achieved results indicate that very good radiation

patterns were obtained when ABCs are implemented at all the edges. The results

of FDTD simulations have shown that we have simulated the wave propagation in

open domains.

Key woras: Maxwell’s curl equations; finite aifference time aomain (FDTD) methoa;

Mur’s first-order absorbing boundary condition (ABC); three-dimensions (3-

D); two dimensions (2-D), transverse magnetic mode (TMz mode).

المستخلص

حل معادلات لالموجات الكهرومغناطيسية باستخدام طريقة الفروق المحددة في هذه الورقة محاكاة تم

لي عوائق من موصل مثا ىمحتوي علالالفضاء ىتوليد الموجات فوروماكسويل مع تطبيق شروط الحدية م

ىايضا فبعدين و ىنتائج ف ىحصول علالينتك وومثلث. تم حساب متجه ب شكلول شريطين متوازيين مث

محاكاة فضاء لانهائى. روحد مال شرط نتائج عند تطبيقالثلاثة ابعاد. وتبين من


112

Sedig S. Farhat

Introduction

Electromagnetic wave propagations will be numerically studied when including an

obstacle in a computational domain and this is not easily described analytically. To

overcome this difficulty, there are many different numerical techniques employed to

calculate the fields such as the FDTD method. It is well known that this method employes

solving Maxwell’s curl equations numerically by utilizing the central aifference

approximation. This method has been applied to solve many kinds of problems such as

in medical application, and in predication of electromagnetic wave propagation, in

studying plasma [2] and in communication system [3]. In this paper, we consider the

propagations of electromagnetic waves in free space without and with including an

obstacle in a domain as well as consider the behaviour of electromagnetic waves without

and with an absorbing boundary condition. The FDTD simulation is studying the

behaviour of EM wave in time in response to to a source exciting the domain. We have

studied the distributions of Poynting vector when interacting of electromagnetic wave

with an obstacle. We constructed the obstacles with different shapes located at the centre

of a domain and the distance between the obstacle and the boundary filled with air. The

obstacles will diffract and scatter the wave which can cause to vary the distributions of

the fields. Therefore, the aim of this work is to describe how 2-D FDTD and 3-D FDTD

approaches is utilized to study electromagnetic wave propagation in space containing a

perfect electric conductor (PEC). Electromagnetic waves will impact with a perfect

electric conductor obstacle as the distributions of the scattered fields will vary when

including different shapes and size. The PEC structures of convenient shapes have been

chosen by mapping each shapes into the domain to make a comparison in term of their

distributions between the simulations. Once the electromagnetic field components are

determined at every time step in each cell then Poynting vector can be calculated in each

pixel and voxel at every time step in two and three dimensions, respectively. There are

many shapes which could generate different distributions. Therefore, many examples can

be studied such as a triangle geometric shape included in a domain. This is a very

complicated structure to construct in a space. It can be done by generating the obstacles

as a mesh mode in a domain. Moreover, the ABCs must be used in the FDTD simulation,

because the computer’s storage ana more memory are limitea. Therefore, a computational

domain must be utilized with limited size [4]. This problem can be solved by employing

a method like absorbing boundary condition (ABC) to terminate a FDTD grid. It is well

known that the space is required to be truncated to simulate an open space to prevent the

reflections coming from the edges. To overcome this problem, it is therefore important to

have the ABC in a computational domain to allow the waves to propagate into the infinite

space without reflecting back. Because, the reflections will cause the waves to interfere

with each other in the computational domain and this will produce reflection patterns.

This will affect the numerical accuracy of the calculations. Therefore, part of this work

was carried out to demonstrate how to implement the ABC and why an absorbing

boundary condition should be included in a computational domain during the calculations

which is very important to improve the accuracy of the calculations. It is also significant

113

Use of Finite Difference Time Domain (FDTD) Technique to Calculate Poynting Vector

to know that one of main advantage of the ABC is reducing computational time by

decreasing the size of computational domain as the calculation will not include

unnecessary large size storage arrays. This will lead to improve the FDTD performance

and then obtain an accurate field distribution. Therefore, the boundaries will be

implemented on all faces by applying the Mur’s approach [1]. This study will investigate

the impact of including an obstacles in the space and the interactions of EM wave with

obstacles which will be observed when the problem space is simulated as if it is

surrounded by an open domain. Therefore, an example illustrating the effect of the

implementation of the absorbing boundary conditions will be provided by computing the

distributions of all components and the numerical calculations of interaction of the

emitted EM wave with obstacles will be demonstrated in the results section.

Method

We can briefly describe the basic of the finite difference time domain (FDTD) method

which was first proposed by Kane Yee [5] in 1966. The technique is a numerical method

based on a finite difference concept that can be applied to find a solution of time

depenaent Maxwell’s curl equations: 𝜕𝐄

𝜕𝑡 =

1

ɛ𝑜∇ × 𝐇 (1.a)

𝜕𝐇

𝜕𝑡= −

1

𝜇𝑜∇ × 𝐄 (1.b)

Where the E is the electric field and H is magnetic field.

The central finite difference approximation method applied to generate six discrete

update equations to simulate a system in three dimensions case. Therefore, the field

components can be written as the first in three dimensions case and second in two

dimensions case since this study in this work is divided into two parts. The following

equations can be utilized to update the electric field components in three-dimensional

simulations [5, 6]:

𝐸𝑥|𝑖+12,𝑗,𝑘

𝑛+1 =𝐸𝑥|𝑖+1/2 ,𝑗,𝑘 𝑛 +

1

ɛ𝑜. (𝑡

𝛿(𝐻𝑧|

𝑖+1

2,𝑗+

1

2,𝑘

𝑛+1

2 − 𝐻𝑧|𝑖+1

2,𝑗−

1

2,𝑘

𝑛+1

2 ) −𝑡

𝛿(𝐻𝑦|

𝑖+1

2 ,𝑗,𝑘+

1

2

𝑛+1

2 −

𝐻𝑦|𝑖+1

2,𝑗,𝑘−

1

2

𝑛+1

2 )) (2.a)

𝐸𝑦|𝑖,𝑗+12,𝑘

𝑛+1=𝐸𝑦|𝑖 ,𝑗+1/2,𝑘

𝑛+1

ɛ𝑜. (𝑡

𝛿(𝐻𝑥|

𝑖,𝑗+1

2,𝑘 +

1

2

𝑛+1

2 − 𝐻𝑥|𝑖,𝑗+

1

2,𝑘−

1

2

𝑛+1

2 ) −𝑡

𝛿(𝐻𝑧|

𝑖+1

2 ,𝑗+

1

2,𝑘

𝑛+1

2 −

𝐻𝑧|𝑖−1

2,𝑗+

1

2,𝑘

𝑛+1

2 )) (2.b)

𝐸𝑧|𝑖,𝑗,𝑘+12

𝑛+1 =𝐸𝑧|𝑖 ,𝑗,𝑘+1/2 𝑛 +

1

ɛ𝑜. (𝑡

𝛿(𝐻𝑦|

𝑖+1

2,𝑗,𝑘 +

1

2

𝑛+1

2 − 𝐻𝑦|𝑖−1

2,𝑗,𝑘+

1

2

𝑛+1

2 ) −𝑡

𝛿(𝐻𝑥|

𝑖 ,𝑗+1

2,𝑘+

1

2

𝑛+1

2 −

𝐻𝑥|𝑖,𝑗−

1

2,𝑘+

1

2

𝑛+1

2 )) (2.c)

And use of the following equations to update the magnetic fields components:

114

Sedig S. Farhat

𝐻𝑥|𝑖 ,𝑗+1/2,𝑘+1/2 𝑛+1/2

=𝐻𝑥|𝑖 ,𝑗+1/2,𝑘+1/2 𝑛−1/2

+1

𝜇𝑜. (𝑡

𝛿(𝐸𝑧|𝑖 ,𝑗,𝑘+1/2

𝑛 − 𝐸𝑧|𝑖 ,𝑗+1,𝑘+1/2𝑛 ) −

𝑡

𝛿(𝐸𝑦|𝑖 ,𝑗+1/2,𝑘

𝑛− 𝐸𝑦|𝑖 ,𝑗+1/2,𝑘+1

𝑛)) (2.d)

𝐻𝑦|𝑖+1/2 ,𝑗,𝑘+1/2 𝑛+1/2

=𝐻𝑦|𝑖+1/2 ,𝑗,𝑘+1/2 𝑛−1/2

+1

𝜇𝑜. (𝑡

𝛿(𝐸𝑧|𝑖+1 ,𝑗,𝑘+1/2

𝑛 − 𝐸𝑧|𝑖 ,𝑗,𝑘+1/2𝑛 ) −

𝑡

𝛿(𝐸𝑥|𝑖+1

2,𝑗,𝑘+1

𝑛 − 𝐸𝑥|𝑖+1/2 ,𝑗,𝑘 𝑛 )) (2.e)

𝐻𝑧|𝑖+1/2 ,𝑗+1/2,𝑘 𝑛+1/2

=𝐻𝑧|𝑖+1/2 ,𝑗+1/2,𝑘 𝑛−1/2

+1

𝜇𝑜. (𝑡

𝛿(𝐸𝑥|𝑖+1/2,𝑗+1,𝑘

𝑛 − 𝐸𝑥|𝑖 +1/2,𝑗,𝑘𝑛 ) −

𝑡

𝛿(𝐸𝑦|𝑖+1,𝑗+1/2,𝑘

𝑛− 𝐸𝑦|𝑖 ,𝑗+1/2,𝑘

𝑛)) (2.f)

With regard to the two-dimensional simulations, we will utilize the transverse

magnetic (TMz) mode and the discrete update equations can be given as [5]:

𝐻𝑥𝑛+

1

2(𝑖, 𝑗 +1

2) = 𝐻𝑥

𝑛−1

2(𝑖, 𝑗 +1

2) −

𝛿𝑡

𝜇0 𝛿(𝐸𝑧𝑛(𝑖, 𝑗 + 1) − 𝐸𝑧

𝑛(𝑖, 𝑗)) (3.a)

𝐻𝑦𝑛+

1

2 (𝑖 +1

2, 𝑗) = 𝐻𝑦

𝑛−1

2 (𝑖 +1

2, 𝑗) +

𝛿𝑡

𝜇0 𝛿(𝐸𝑧𝑛(𝑖 + 1, 𝑗) − 𝐸𝑧

𝑛(𝑖, 𝑗)) (3.b)

𝐸𝑧|𝑖,𝑗 𝑛+1=𝐸𝑧|𝑖 ,𝑗

𝑛 +1

ɛ𝑜. (𝑡

𝛿(𝐻𝑦|

𝑖+1

2,𝑗

𝑛+1

2 − 𝐻𝑦|𝑖−1

2,𝑗

𝑛+1

2 ) −𝑡

𝛿(𝐻𝑥|

𝑖 ,𝑗++1

2

𝑛+1

2 − 𝐻𝑥|𝑖,𝑗−

1

2

𝑛+1

2 ))(3.c)

The FDTD updating equations provided in equations (2) and equations (3) will be

applied to solve three- and two-dimensions cases, respectively. These equations can be

implemented in the computer programs to calculate the electric and magnetic field

components at each time step in a computational domain with including the obstacles at

the centre of a domain. The calculated field components will be used to compute the

Poynting vector that given by:

𝐒 = 𝐄 × 𝐇 (4)

The cross product of the E with H will provide the direction of propagation of the EM

wave in space. Therefore, the Poynting vector (Watt/m2) can be computed in each pixel

in 2-D case and each voxel in 3-D case.

Furthermore, the first-oraer Mur’s absorbing bounaary conaition will be applied and

the FDTD updating equation at the boundary as an example in 3-D case at x=0 gird

boundary [1] given by:

𝐸𝑧𝑛+1(0, 𝑗, 𝑘 + 1/2) = 𝐸𝑧

𝑛(1, 𝑗, 𝑘 + 1/2) +(𝑐𝛿𝑡−𝛿)

(𝑐𝛿𝑡+𝛿)(𝐸𝑧𝑛+1(1, 𝑗, 𝑘 + 1/2) −

𝐸𝑧𝑛(0, 𝑗, 𝑘 + 1/2)) (5)

Similar equations will be implemented for other electric field components in mesh

walls in 3-D and 2-D simulations which can be applied to absorb the reflections generated

from the six boundaries in 3-D FDTD simulations and four boundaries in 2-D FDTD

simulations. Therefore, the performance of Mur ABC will be demonstrated in the result

section.

115



The FDTD calculations were performed, the results of simulations were demonstrated

and the output of the programs was wrote by a computer MATLAB (R2013a)

programming language. The FDTD simulations were written based on equations (2) and

equations (3) for computing the field components in 3-D FDTD and 2-D FDTD,

respectively. These components will be utilized to calculate the Poynting vector based on

equation (4) as a pixel by pixel in two-dimensional in the x-y plane whereas a voxel by

voxel in three-dimensional in the x, y and z directions. The size of each cell was chosen

as a uniform mesh in two and in three directions based on ten grid cells per wavelength

which is required for accuracy and the time step must satisfy the Courant condition in

order for the solution to be stable, which is provided by [1, 2]:

∆t ≤δ

c (n)1/2 (6)

Where the δ is the space increment, c is the speed of light in space and n is the

dimensionality of the problem such as n=2, 3 for simulating a two-dimensional and three-

dimensional systems, respectively.

The FDTD simulation will consider the behaviour of electric and magnetic fields every

time step due to exciting a domain and can study the effect of the boundary condition on

the calculations by comparing the results of the simulations when including the ABC to

obtain an accurate result and the simulation without including ABC. The latter will affect

the calculation and the accuracy of the calculations as the EM wave when reaching the

end of a domain, the wave reflects back in space. Therefore, we have studied the

propagation behaviour of the TMz wave without ABC and with Mur’s ABC. The purpose

of the numerical example is to aemonstrate the performance of the Mur’s ABC. The

numerical results of the TMz mode showed that the source of excitation generated the

wave and spread on the x-y plane by using a sinusoidal wave with frequency 2 GHz

propagating in the x-y plane in 2-D and all snapshots are taken at 500 time steps. From

figure 1 can demonstrate that how the TMz wave propagate in free space and once the

waves reaching the boundary, the waves will hit the walls and then reflecting back to the

domain and propagating everywhere in the problem space then producing the reflection

patterns. It can be clearly seen that there are significant differences in the distributions

between the simulations as well as the simulation without the ABCs affected a uniformity

of the distribution of the Poynting vector. The reflection patterns appeared in the space as

shown in figure 1. This pattern can be removea by applying the Mur’s absorbing bounaary

condition, figure 2 shows the performance of the ABC when applying the equation 5

which found to be worked perfectly as generated the circular patterns and the grid

appeared to extend into infinite. It can be said that we simulated an open domain and the

example is applied to validate the implementation of the ABC and the numerical

calculations have illustrated that the circular patterns produced when the wave spreading

out from the source even though the waves reached at all edges, because waves absorbed

by the ABCs. The boundary condition is very significant in the calculations in the FDTD

ana we usea the Mur’s absorbing bounaary conaition in three-dimension case as well to

116

Sedig S. Farhat

reduce any reflections come from boundary to obtain good and an accurate distribution.

Therefore, the results obtained in three dimensions case will demonstrate the circular

patterns that can be observed in the calculations as demonstrated below i.e., the signals

are absorbed by the boundary condition when reached at all boundaries. Moreover, we

can simulate a computational domain with the obstacle included in a space. There are

many type of obstacles can be included in the computational domain in term of the shapes.

We can use of perfect electric conductor (PEC) obstacles which have inserted in the

domain as different shapes such as small square, circular, two parallel strips and triangle

as shown in figure 3 (A, B, C and D). The domain in 2-D FDTD is discretized into 100 ×100 cells in each example. We demonstrated the effect of a PEC obstacle on the

distributions as the EM waves interact with a PEC obstacle by scattering, reflection and

diffraction. The diffraction case can be achieved when an obstacle or an aperture of shape

is located between the source of an excitation and point of observation i.e., the diffraction

will generate when the waves come cross a single slit, double slit or an obstacle in a space.

This will cause the waves bend around the obstacles or during an aperture. The diffraction

will allow the wave to transmit its energy around obstacles. Therefore, the purpose to

include the obstacle in each calculation is that to observe the distribution of the Poynting

vector when placing different shape in 2-D as well as in 3-D model. Therefore, we have

made of two similar simulations in 2-D, the first case is the simulation without an obstacle

as shown in figure 4 compare with the second case which is the simulation with including

an obstacle such as a small square as shown in figure 5. It was noted that the distributions

of the Poynting vector components affected when the waves reached the small square, the

waves are scattered by the obstacle. This simulation should be compared with example

when increased the size of the obstacle as illustrated in figure 6. It can be noted that the

solution of the field reached the sinusoidal steady state response as the wave updated

behind the structure and small values appeared in each pixel and this is known as the

diffraction when the waves passing around an obstacle or during a hole while the

phenomenon of reflection occurs when the wave propagating from a one medium

boundary to second medium boundary, but in this study we have a PEC boundary as a

second medium which will cause to generate total reflections as there is no penetrations

will be seen inside an obstacle. This means that there is no transmission wave travelling

into a second medium. This is due to the fact that the electric field components set to be

equal zeros at regions of the obstacles. The interference patterns can be produced when

an incident waves hitting an obstacle and then the waves were reflected back in space as

shown in figure 5 and figure 6. Moreover, the example is given in figure 3 (C) was

simulated by constructed the two parallel strips made of the PEC opened from both sides

and inserted in the middle of a problem space. The domain can be excited by a point

source placed at the left side of the structure.

From figure 6, there is a shadow area is clearly appeared behind the obstacle, this can

be observed when increase the size of the obstacle, it can be seen that more reflection

occurred on the front of the obstacle as the incident wave propagated in a domain until

hitting the obstacle and then reflected to a problem space. It can be seen that the EM

waves diffracted when propagating within a domain included obstacle and bending

117


around PEC obstacle as the wave updated in each pixel behind the obstacles, it is possible

to obtain the signals behind the obstacle by recording the signals during a simulation as

shown in figure 7 (A and B) which is demonstrated that the simulations reached a steady

state to ensure accurate results and by increasing the size of the obstacle, the amplitude

of the signal decreased. Figure 8 shows that one of the main results of the interaction of

electromagnetic waves with obstacles, the diffraction can be seen and the example has

shown that the waves excited in a problem space and propagated between two strips until

reached the end of the structure after that start spreading out of the slit. This arrangement

is demonstrated that the wave will bend when it reaches the strips on the left side of the

structure and then the wave propagated within strips as well as steady state behaviour is

reached. This result means that the structure appeared as a new source to transmit the

signal from the left side to right side within the strips and this is due the use of two parallel

strips have properties of PECs. Moreover, in the next example the source was inserted

between two parallel strips, it can be noted that the components of Poynting vector

appeared identical, this means that the waves are propagating bilaterally between the

strips. This means that the same energy transmitted on the left side is generated on right

side and the distribution appeared as spherical waves as shown in figure 9. By comparing

figure 8 with figure 9, it can be seen that different distributions generated in the image,

this is due changing the location of the excitation source. In the first case the source placed

outside the structure while second case the source placed between the two parallel strips.

Furthermore, it can be made a comparison between the simulations results when placing

different obstacle shape in space as the example the Poynting vector was affected when

placed a triangle in the space. It can be noted that the signals propagated everywhere in a

space and when reached the obstacle split to propagate into the upper and lower regions

of the obstacle and generated the same patterns and the similar wave produced as shown

in figure 10. Furthermore, when we placed in a domain such as a triangle as shown in figs

11 and 12, the Poynting vectors distributions are slightly different when making a

comparison with simulations results that are shown in figure 11 and figure 12. The only

difference is that the obstacle in figure 11 caused more scattering in lower regions

compared with obstacle in figure 12 which is caused more scattering in the upper region.

Therefore, by comparing when flipping the obstacle structure, the EM fiela’s patterns

varied. Moreover, the simulation results indicate that it seems that combine figs 11 and

12 to generate the similar result that produced in figure 10. This means that the incident

waves affected in the upper and lower regions in space. Therefore, it can be observed that

the intensities of Poynting vector appeared identical when comparing the lower region

with upper region from the middle of a domain in both simulations but when increasing

the size of obstacle the interference patterns can be clearly observed and the interference

patterns appeared as the incident wave excited by a source in a problem space and the

wave propagate until hitting the obstacle then reflected back to the domain and then two

waves added together in the same medium. The interference can be constructive or

destructive and the interference will cause to vary the intensities of each component.

Furthermore, we have done the similar calculations in 3-D FDTD, the domain is

discretized into 100 × 100 × 100 uniform cells in the x, y and z directions after that a

118

Sedig S. Farhat

triangle shape placed in centre of the space in three dimensions as shown in figure 13 (A).

Figure 14 shows the example of the images produced in the 3-D FDTD and the snapshots

are taken at 250 time steps and circular radiation patterns appeared in the results. This can

be indicated that the first order Mur’s absorbing boundary condition (ABC) is an efficient

to apply to absorb the EM field at boundaries in three dimensions problem. Figure 15 is

displayed the field components and can be noted that there are no the electric or magnetic

fields produced in the obstacle, this is due to the fact that the obstacle has property of the

perfect electric conductors (PECs).Therefore, two different obstacles shapes included in

the FDTD domain as shown in figure 13 (A and B). This will vary the distributions of the

fields in the domain as can be clearly seen that there are two distributions generated in

the space as can be seen in figure 14 and 15. The difference in the numerical results

between figs 14 with 15 can be observed as more signals generated behind the second

case as shown in figure 15 and the lower part is cut from the middle of the structure and

there is no PEC which it is filled by a free space. It can be compared the results of

simulations of the 2D FDTD with 3-D simulations when placed the triangle shape as

shown in figure 10 and figure 14. It can be noted that high amplitude of signals generated

between the obstacles and the source of excitation compared with behind the obstacles

and also the shadow regions clearly appeared in the images in two simulations as there

are less signals generated in this area. This is because there are no signals propagated

inside the obstacles. Moreover, the example for two parallel strips in three-dimensional

when including in a domain as shown in figure 16 and exciting the problem space by a

source located between the two strips. The result of the simulation showed that the wave

is propagating bilaterally. This achieved simulation result is a quite similar to the one

observed in 2-D FDTD simulation as have demonstrated in figure 9.

Figure 1. Snapshots of Poynting vector (Watt/m2) taken at 500-time steps, without

including an absorbing boundary condition (ABC) in the computational domain in 2-D

FDTD domain.

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119


Figure 2. Snapshots taken at 500 time steps and the computational domain is terminated

by the first-oraer Mur’s ABCs in 2-D FDTD domain.

Figure 3. Two-dimensional: Four different obstacles are located in the centre of the

domain and the obstacles have property of the perfect electric conductor (PEC). The

FDTD cell is equal to a one-tenth of the wavelength of interest.

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C) D)

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Sedig S. Farhat

Figure 4. The source of excitation is placed on the left side of a domain without including

an obstacle in space in 2-D FDTD domain.

Figure 5. An obstacle as a square shape is located at the centre of a domain in 2-D FDTD.

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Figure 6. An obstacle as a circular shape is placed at the centre of a domain in 2-D

FDTD.

Figure 7. Signals were recorded behind the obstacles, exactly between the obstacle and

the right side of the computational domain: A) the first case behind the square obstacle

and B) second case behind the circular obstacle.

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Sedig S. Farhat

Figure 8. The source of excitation is placed between the left boundary and two parallel

strips. The wave is concentrated to propagate between two strips in 2-D.

Figure 9. the source is placed between two parallel strips at the centre of a domain in 2-

D FDTD.

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Figure 10. Triangle obstacle shape is placed at the centre of a domain in 2-D.


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Figure 13. The implementations of two different shapes of obstacles have the electric

property of a PEC placed at the centre of a domain. The obstacles constructed in the

computational domain as a mesh mode in 3-D FDTD.

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115


Figure 14. Triangle obstacle shape set as a PEC in domain in 3-D FDTD.

Figure 15. Triangle obstacle shape set as a PEC in domain in 3-D FDTD.

Sx in xy plane

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Sedig S. Farhat

Figure 16: The source of excitation is placed in the middle of two parallel strips in 3-D

FDTD domain.

Conclusion

We have demonstrated a solution of the Maxwell’s equations by applying the FDTD

method. Many different cases have been reported in this work describing the distributions

of Poynting vector of EM waves in free space when the EM waves interacted with the

obstacles included in a domain. It was found that the FDTD method is extremely useful

to apply for solving Maxwell’s equations numerically as it is aifficult to solve otherwise.

The problem analytically as well as the first-order Mur’s absorbing bounaary conaition

approach is proved to be an efficient condition to improve the FDTD numerical

performance and also saved the computational time.

References

[1] Mur, G. (1981). Absorbing Boundary Conditions for the Finite Difference

Approximation of the Time Domain Electromagnetic Field Equations, IEEE

Transactions on Electromagnetic Compatibility, EMC-23, 377-382.

[2] Otman, S. and Ouaskit, S. (2017). FDTD simulations of surface Plasmon using the

effective permittivity applied to the dispersive media. American journal of

electromagnetic and applications, 5, 14-19.

Sx in xy plane

-1

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-7

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-0.5

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-7

117


[3] Khitam, Y. E., Sami, A. A., and Mohammed, M. S. (2018). 3D-FDTD Head Model

Exposure to Electromagnetic Cellar Phones Radiation, American journal of

electromagnetic and applications, 6, 42-48.

[4] Tony, W. H., Wang, Y. C. and Li, J. (2016). Development of a 3D staggered FDTD

scheme for solving Maxwell’s equations in Drude medium, computers and

mathematics with application, 71, 1198-1226.

[5] Yee, K. S. (1966). Numerical Solution of Initial Boundary Value Problems Involving

Maxwell’s Equations in Isotropic Meaia, IEEE Transactions Antennas ana

Propagation, 14, 302-307.

[6] Taflove, A. and Morris, E. (1975). Numerical Solution of Steady State

Electromagnetic Scattering Problems using the Time Depenaent Maxwell’s

Equations. IEEE Transactions on Microwave Theory and Techniques, 23, 623-630.

119


Effect of Feeding Fry Red Tilapia with Spirulina on Fish Health

Entisar Mohamed Eljaziri1 and HishamAddin Bin Omar

University Putra Maysia, Faculty of Agriculture, Department of Aquaculture. [email protected]

Abstract

Feeding of Red Tilapia with commercial Spirulina microalgae experimental study (this

volume) gave remarkable results. A complementary study investigating fish health was

carried out. It showed that the best results were obtained for fish feed with 3% Spirulina in

concordance with the experimental study in which the best return was achieved by this

ration. Survival rate, reduction in mortality and protection from bacteria infection was

ubiquitous with 3% ration showing maximum results.

Keywords: Red Tilapia; Spirulina feed; Survival rate; Bacterial infections.

المستخلصأجريت دراسة تجريبية على تغذية سمك البلطي الأحمر بواسطة طحالب السبريولينا الدقيقة التجارية )هذا المجلد( وقد أعطت

%6نتائج بارزة. كما تم اجراء دراسة تكميلية عن صحة السمك والتي اضهرت أن أفضل النتائج قد تم الحصول عليها من وجبة

ياة على قيد الح فرص البقاءة التجريبية التي أظهرت افضل مردود بهذه الوجبة. أن معدل سبريولينا وهو ما يتوافق مع الدراس

أعطت أفضل النتائج. %6تخفيض الوفاة ومقاومة الإصابة بالبكتريا كانت عامة غير ان وجبة و

Introduction

The global aquaculture industry has expanded in the last few decades, reaching

maximum production value in 2010. FAO foresees that world production of fisheries and

aquaculture sector will reach 172 million tons in 2021, due to increased demand for fish.

This rise will be attributed mostly to aquaculture production projected to expand by 33%

in the period 2012–2021 (FAO, 2012).

Tilapia is among three genera species of economic importance (Eljaziri and Bin Omar,

2021 and refrences cited therein). Eljaziri and Bin Omar (this volume) showed, after trials

with different percentages of microalgae Spirulina feed, showed that 3% ration gives

excellent return in feeding Red Tilapia


121


In this short note we present results of the consequence of feeding Red Tilapia with

Spirulina on the health of the fish under the aforementioned experiment conditions for

different ratios of feed.


A total of twelve cages were used and arranged in a concrete tank at the hatchery, TPU,

UP Malasysia. Details of the specifications of the cages, experiment conditions and

analytical methods are described in Eljaziri and Bin Omar (2021). A mixture of Spirulina

commercial fish feed with ground commercial fish feed was used. Feeding rations of 0%,

1%, 3%, 5% and 7% were used twice a day for three months.


Nutritional Composition of Feed Among the different ratios of spirulina, ranging from 1% to 7%, the 3% ration gave

the best economic return in terms of growth patter, fish length, fish activity and coloration

(Eljaziri and Bin Omar, 2021).

Effect of Feed Diet on Survival Rate of Red Tilapia

For the entire experimental period, positive survival rate was achieved with 1% and

3% forming the highest compared to other treatments (Table 1). This shows the impact

of feed incorporated with spirulina on fish survival as it may bust the fish immune system.

This is consistent with the studies of El- sheek et al. (2014), Jana et al. (2014) and

Abdurrahaman and Ameen (2014).

Table 1. Percentage of Survival.

Treatment Percentage of Red Tilapia survival %

0% 58.33%

1% 75.00%

3% 75.00%

5% 54.17%

7% 54.15%

Effect of Spirulina Feed on Fish Immune System

In order to test Spirulina ability in strengthening the fish immune system, a bacteria

stock was formed using streptococcus aglactea, after been diluted with 10-5 colony to

reach the standard count of 30 – 300. A 0.3ml of bacteria was injected into fish samples

taken from different rations of spirulina fed fish. For two weeks, after the injection, the

mortality rate was recorded.

121


Out of thirty samples, injected, fish fed with 1% and 3% had the lowest mortality rate.

The one-way ANOVA analysis result shows no significant difference between the ratios

at p>0.05. This proved that spirulina has the ability to strengthen the fish immune system,

though excessive feed may result in negative effect (Nakagawa and Gomez-Diaz, 1995).

For comparison, a new fish sample, fed with different rations, was injected with

0.04ml of bacteria for two weeks. The result showed a bit higher mortality rate when

compared with sample fed with spirulina for 13 weeks (Table 2). This, also, is a prove of

the adapitbility of spirulina to fish resulting in strengthening of the fish immune system

resulting in less mortality rate. High mortality rate, however, was observed for two weeks

feed with no much difference between the ratios.

Table 2. Mortality for fish injected with 0.04ml bacteria (230.5×10-5 FCU/ml).

Spirulina No of fish die No of fish live %of die fish %of live fish

0% 21 9 70% 30%

1% 18 12 60% 40%

3% 16 14 53% 47%

5% 15 15 50% 50%

7% 15 15 50% 50%

Effect of Spirulina on Fish Hemoglobin

Hematological parameters are presented in Table 3. The results indicate that

Erythrocyte RBC count is almost within the same range across the concentrations except

for 3% with lowest count 1.9±0.3mg/l as well as hemoglobin of blood (HB) with

8.3±1.6g/dl. The PVC was also at the same range but lower (20%) in 3% and 5%.

Mean Corpuscular volume (MCV) and mean corpuscular hemoglobin concentration

(MCHC) also show almost equal count among the concentrations. With regard to

thrombocytes andplasma protein, the results also fall almost within the same range across

all concentrations. However, WBC count differed between the concentrations with 5%

having the highest 10.8±9.3g/l concentration.

The hemoglobin result for the parameters is within the references range reported by

some studies. RBC ranges, from 1.9 – 2.4g/µl, are within the range described for hybrid

tilapia 1.91 – 2.83 106//µl, (Hrubic et al, 2000) and for Nile tilapia 0.7 – 28 x106/mm2

(Bettencourt et al, 2003). The HB count on the other hand ranges from 8.2 – 10.9 g/l.It is

also within the range described for Nile tilapia 6.8 – 15.98g/dl (Bettencourt et al, 2003)

and 7.0 – 9.8g/dl described for hybrid tilapia (Hrurbic et al, 2000) though a slight

difference occurs at 5% with 10.9g/dl. The PVC range 20 – 30% are also, within what

described for hybrid tilapia.

The MCV mean value obtained in this study is within the range of corresponding values

described for hybrid tilapia (Hrubic et al, 2000) and Nile tilapia (Bettencourt et al., 2003).

The MCHC mean value ranged 348 – 413g/l in this study which is similar to those

reported for Nile tilapia 19.84 – 87.73% (Bettencourt et al., 2003) and in Nile tilapia

(Isikawa et al., 2007) while the thrombocyte value and plasma protein is similar to those

for hybrid tilapia (Hrubic et al, 2000).

122


Table 3. Hemoglobin response of red tilapia feed different spirulina ratio.

Spirulina Concentrations

Parameters 0% 1% 3% 5% 7%

RBC(g/µl) 2.4±0.25 2.2±0.26 1.9±0.31 2.2±0.47 2.2±0.20

HB(g/dl) 8.2±1.4 9.7±0.27 8.3±1.6 9.7±1.1 10.9±1.8

PCV (%) 30±0.3 30±0.3 20±0.2 20±0.5 30±0.3

MCV(FL) 108.0±8.1 118.0±3.2 119.6±14.7 110.4±6.0 131.8±9.8

MCHC (g/l) 413.3±35.9 360±14.7 376.0±11.0 391.2±14.4 348.2±15.5

WBC (g/l) 2.1±1.0 5.7±4.7 5.3±3.5 10.8±9.3 2.8±2.6

THROMBO(g/l) 17.8±8.5 22.4±12.1 23.3±12.4 20.4±15.9 23.6±18.7

P PROT 5.7±5.9 40.8±6.6 39.4±3.2 39.8±3.3 43.8±3.1

The WBC mean value range 2.1 – 10.8g/l in this study is also similar to those reported

for hybrid tilapia 2.1 – 15.4g/l (Hrubic et al, 2000). The result indicated the spirulina

impact on fish immune system as lymphocyte developed for immune response.

Conclusion

Feeding fish with commercial spirulina diet has shown encouraging results in terms

of overall growth of fish (Eljaziri and Bin Omar, 2021). A complementary study also

showed that it promtes survival rate, health and strengthen the immune system.

Among the different ratios of spirulina studied, 1% and 3% showed overall

remarkable performance in fish growth rate, survival rate, reduction in mortality rate and

strengthening of the immune system to protect the fish from any bacterial infection as

well as the fish activity and coloration as compared to the blank. Acceptable results were

shown by the other ratios which, however, were below the 1% and 3% ration.

Authors’ Resposibility

The authors substantially contributed to the conception and design of the study,

acquisition, analysis and interpretation of data; all authors are responsible for the

intellectual content of the manuscript and approved the final version of the article to be

published.

References

Abdurrahman, N. M.and Ameen, H. J. H. (2014). Replacement of fishmeal with

microalgae Spirulina on common carp weight gain, meat and sensitive

composition and survival. Pakistan Journal of Nutrition, 13(2), 93-98.

Bittencourt, N. dl. R., Molinari, L. M., Scoaris, D. O., Pedroso, R. B., Nakamur, C. V.,

Ueda-Nakamur, T., et al., (2003). Haemotological and biochemical value for Nile

tilapia Oreochromisniloticus cultured in semi-intensive system. Actascientiarum.

Biol. Sci.

123


25(2), 385-389.

Eljaziri, E. M. and Bin Omar, H. (2021). Biology and growth performance for Fry Red

Tilapia feed with Spirulina. Libyan Journal of Science, 24, 39-54.

El-Sheekh, M., El-Shourbagy, I., Shalaby, S., and Hosny, S. (2014). Effect of feeding

Arthrospiraplatensis (Spirulina) on growth and carcass composition of hybrid

red tilapia (Oreochromisniloticus x Oreochromismossambicus). Turkish Journal

of Fisheries and Aquatic Sciences, 14, 471-478.

FAO (Food and Agriculture Organisation of the United Nations). (2012). The state of

world fisheries and aquaculture 2012. Food and Agriculture Organisation of the

United Nations, Rome. www.fao.org/docrep/016/i2727e/i2727e00.htm Hrubec, T.C., Cardibale, J. L. and Smith, S. A. (2000). Hematology and plasma chemistry

Reference intervals for cultured tilapia (Oreochromis Hybrid). Veterinary

clinical pathology. 29 (1), 1-12.

Ishikawa, N.S., Ranzani-paiva, M.J.T., Lombardi, J. V. and Ferreira, C.M. (2007).

Hematological parameters in Nile tilapia,Oreochromisniloticus exposed to sub-

total concentrations of mercury. Int. J. Brazilian Archv. Biol& Tech., 50 (4), 619-

626.

Jana, A., Saroch, J. D., and Borana, K. (2014). Effect of spirulina as a feed supplement

on survival and growth of Pangasiussutchi. International Journal of Fisheries and

Aquatic Studies, 1(5), 77-79.

Nakagawa, H.and Gomez-Diaz, G. (1995). Usefulness of Spirulina sp. meal as feed

additive for giant freshwater prawn, Macrobrachiumrosenbergii. Suisanzoshoku,

521-526.

121

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informative introduction and end with a short conclusion, summarizing the results obtained and

the goals achieved. All titled headings for sections should be centred and subsections left

justified and written in boldface with size 12. The text should be justified in alignment and

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year, they should be distinguished in both the text and the reference list by small letters

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titles should be written in full or abbreviated according to the standard abbreviation of

periodical titles.

The style of entries for books should be as follows:

Schwabl, F. (2002). Quantum Mechanics, 3rd edition, Springer-Verlag, Berlin, 210p.

For unpublished thesis:

Nolland, D. J. (2000). Quantum Field Theories with Fermions in the Schrodinger

Representation, Ph.D. thesis, University of Durham, Durham, England.

For journal articles:

Knill, R. J. (1971). On the homology of a fixed point set, Bull., Am. Math. Soc., 77, 184-190.

Mansfield, P. (1995). The vacuum functional at large distances, Phys. Left., B 358, 287-296.

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For articles published in symposia:

Jafri, S. M. H. and Rateeb, F. B. (1978). Chenopodiaceae. In: The Flora of Libya

(Jafri,. S. M. H. and A. El-Gadi, eds). University of Tripoli, Faculty of Science,

Department of Botany, Tripoli, Libya, No. 58.

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A manuscript (on CD plus three hard copies) should be sent to the editor in chief or any

member of the editorial board at the following mail address:

The Libyan Journal of Science

University of Tripoli

Faculty of Science

Editorial Office

P.O. Box 13503

Tripoli, Libya

E-mail: [email protected]

url: http://libyanjournal.atspace.co.uk

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المجلة الليبية للعلوم

تعليمات النشر

عن طريق كلية العلوم بجامعة طرابلس وهي تهدف لنشر البحوث العلمية سنوياتنشر المجلة الليبية للعلوم مرتين والتطبيقية وتقبل المجلة مخطوطات البحوث التي لم يسبق نشرها والتي ليست البحثةالاصيلة في جميع افاق العلوم

أثنين وتحال الي )التحكيم( عن طريق متخصصين العلمية المراجعةتحت التقييم للنشر في مكان آخر. تتم عملية ملخصامكتوبه بلغه عربيه سليمه وتشمل الورقة. إن من مسئولية الكاتب أن تكون اختلافهمامراجع ثالت في حال

بلجنة التحرير في اعداده(. الاستعانة وبالإمكان) الإنجليزية باللغةسم( بحيث تكون (A4 21x29.7علي ورق Simplified Arabic: تتم طباعة المخطوط بخط نص المخطوط

لتتسق مع شكل المجلة.سم 3.3الأعلى والاسفل ومن سم من اليمين واليسار 3الهوامش ( أسم البحث، 1: يطلب من الباحثين اعداد مخطوطاتهم حسب النسق التالي أو قريب منه: )محتويات المخطوط

لمستخلص )عربي وانجليزي( مع كلمات ( ا3( أسم الباحث او البحاث كاملا وعناوينهم البريدية والإلكترونية، )2)( 6والنطاق الجغرافي ... الخ، ) المدروسةاو المستعملة( الطرق والتقنيات والتجارب 5، )المقدمة( 4دالة، )

( 11( المراجع و)11( شكر وتقدير )اختياري(، )9( الاستنتاجات، )3، )المناقشة( 7الحسابات والتحاليل والنتائج، ) الملاحق )ان وجدت(.

Simplified, وممركزا في المنتصف ومكتوب بخط مختصرا: يجب ان يكون عنوان البحث عنوان البحث

Arabic سم(.2بسنتمترين ) الصفحةداكن وأن يكون تحت أعلي 16بحجم داكن في 11حجم Simplified Arabicأسفل العنوان بخط الكاملة الأسماء: تدرج الأسماء والعناوين

المنتصف.كلمه، مكتوبه كفقره 311لايزيد عن و الورقة: يجب أن يكون المستخلص متكاملا ودالا علي محتوي المستخلص

داكن في 11بخط حجم ’’ المستخلص’’داكن ويكتب العنوان 11وحجم Simplified Arabicواحده بخط منتصف السطر .

سم عقب 1.5ت وتوضع علي مسافة : تكتب بنفس خط المستخلص ولا تزيد عن خمس كلماالكلمات الدالة المستخلص مباشرة.

: يقسم النص الي أجزاء واجزاء فرعيه )اذا لزم الامر( بعناوين واضحه. يبدا النص بمقدمه )تحتوي على النصوهدف البحث( وينتهي بالاستنتاجات التي تلخص النتائج والاهداف المتحصل عليها السابقةوالدراسات المشكلة

داكن علي ان يكون 14من اليمين وتكون جميعها بخط الفرعيةالاجزاء في المركز والعناوين وتوضع عناوين النص محددا من الجهتين .

النص في ملاحق عقب قائمة المراجع. انسيابالتي قد تعوق التفصيلية الفنية: توضع المعلومات الملاحقاليها الإشارة: إن من مسئولية الباحث التأكد من صحة المراجع ودقتها. توضع قائمة بالمراجع التي تمت المراجع

الموجود للأصل العودةوتتم القائمةفي النص وفي حال وجود مراجع لم يشر اليها سيقوم المحررون بشطبها من

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وتتم الاشارة الإنجليزية باللغةلمراجع بخصوص اSuggestions to Authors الإنجليزية باللغةفي التعليمات بنفس النسق. العربية باللغةللمراجع : يتم الرجوع للتعليمات باللغة الانجليزية فيما لم يتم ذكره هنا.ملاحظة

:عنوان المجلة

The Libyan Journal of Science

University of Tripoli

Faculty of Science

Editorial Office

P.O. Box 13503

Tripoli, Libya

E-mail: [email protected]

:الموقع الالكتروني للمجلة

url: http://libyanjournal.atspace.co.uk

Volume 24 2021

المجلة الليبية للعلوم

(مجلة دولية)

منشورات

كلية العلوم

جامعة طرابلس

volume 24 2021 the libyan journal of science

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