Download - Andreas Richter room U2090 Tel: 218 62103 e-mail: [email protected]

Andreas Richterroom U2090

Tel: 218 62103e-mail: [email protected]

Anna Serdyuchenkoroom U 4150

Tel: 218 62120 e-mail: [email protected]

A. Richter & A. Serdyuchenko, Measurement Techniques SS 2011

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Practical Measurement Techniques consists of

• a series of lectures about selected measurement techniques in environmental science

• a series of lectures related to the lab experiments

• the lab experiments

• an oral exam at the endA. Richter & A. Serdyuchenko,

Measurement Techniques SS 2011- 3

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9– 11 11 – 13 14 – 16

April 6

Introduction

(Serdyuchenko)

Fourier Transform Spectroscopy

(Winkler)

Cavity Ring Down Spectroscopy

(Horstjann)

April 13

Satellite Image Analysis

(Melsheimer)

Radioactivity

(Pittauerova)

Measurements of Trace Gases

(Richter)

April 20

Meteorological Measurements

(Richter)

Radioactivity

(Pittauerova)

Absorption Spectroscopy

(Serdyuchenko)

May 4

DOAS

(Richter)

Measurement Techniques in Oceanography

(Mertens)

June 29

Summary and Rehearsal

(Richter / Serdyuchenko)


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• In total 4 lab experiments have to be completed successfully

• The labs will take place on Wednesdays from 10 a.m. until 5 p.m. if not stated otherwise

• The labs will be performed in groups of 2 students each

• Lab instructions, including descriptions of the experimental setup, the tasks to be performed and further literature are available for every experiment on the Measurement Techniques website

http://www.msc-ep.uni-bremen.de/services/lectures/Measurement_tech_SS11-2.html


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• Please get a copy of the lab instructions from the web at least 2 weeks before the lab takes place

read them carefully – if you come unprepared, the tutor will send you home and fix a new date at his convenience

• At least one week before the labs take place contact the lab instructor about the exact time and location of the lab, and perhaps have a first look at the instruments you will use

• For each lab experiment a lab report / protocol has to be written

• For the first two of the four labs each student has to hand in an individual report

• For the remaining two labs one report per group is sufficient


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• The complete reports have to be handed in 2 weeks after the lab to the tutor

• If the report is not accepted by the lab instructor it can be corrected no more than TWICE within two weeks after receiving it from the lab instructor

• A special report form will accompany you through the practical and the review process. This form will be given to you at the end of this lecture and has to be handed in at the end of semester

• You will need this report with all signatures to be admitted to the oral exam


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Note: If you: fail to show up, are not prepared appropriately, submit a revised report which is still not accepted by the

instructor

you will have to do an additional experiment at the end of the semester to be admitted for the exam.

Extra experiments can only be done once and should you fail this one also, you will not pass the course.


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In this set of experiments, you will not be exposed to undue danger by inflammable or hazardous material or ionizing or other harmful radiation. However, you should be aware of some general safety considerations.

Don‘t eat or smoke (this might damage the experiment).

If anything is defect, inform your tutor immediately.

Never construct, modify, or disconnect electrical circuits under voltage applied.

Never look into laser beams.

Be informed about emergency exits and fire extinguisher sites.

On alert, immediately leave the lab room.

Don‘t cause danger to yourself or anybody else!


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• for each experiment, you will have to submit a report

• students of the same group submit two separate and two joint reports

• after the experiment, you have 2 weeks for writing the report and submitting it to the tutor

• reports are prepared with a word processor (word, latex, …)

• the length of the report is typically 6 – 8 pages

• the supervisor will read the report and usually ask for some revisions / corrections / additions / changes

• you then have another week to submit a corrected report

• if necessary, you will have to submit a second revision

• should the supervisor still not accept your report, this will be discussed with the lecturers (A. Richter and A. Serdyuchenko). If all else fails, you will have to take another (additional) experiment

• only when all your reports have been accepted, you will be admitted to the oral exam


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• ideally, your report should enable another scientist to set-up a similar experiment, to repeat the measurements and to compare his/her results with yours

• it should also give the motivation why things have been done the way they were done

• for the purpose of the practical, it should show that you have understood the experiment

• questions to answer in the report:

1.What have you done?

2.Why have you done it?

3.How have you done it?

4.What are the results?

5.What are the associated errors?

6.What are the conclusions?


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1. Title of the experiment: group and name of the students; date

2. Introduction: Short description of the experiment and its objectives

3. Theoretical background: Scientific background on which the experiment is based

4. Experimental set up: Description of the set up used; components and their principle of operation

5. Experimental procedure: Description of each step followed during the experiment, indicating the time and relevant details

6. Data analysis: Description of the data obtained, analysis and conversion procedures applied to obtain the results for interpretation

7. Results and error analysis: Final numerical and graphical results with the corresponding associated error. A detailed description of the error analysis should also be included

8. Discussion of results: Interpretation of the final results in relation to the objectives of the experiment. You can use the questions given in the instructions for the experiment as a guideline

9. Appendix: Raw data in a table, in graphs or on CD


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• in addition to the explanations provided in the experiment description and lecture, you are expected to use other sources of information (papers, books, web pages, discussion with your colleagues)

• any information source used must be acknowledged in the text through appropriate citations

• quoting another text verbatim (“cut and paste”) is usually not acceptable, and has always to be indicated by using quotation marks

• if you can’t say it in your own words, you have probably not understood it

• quotes from the experiment description are not acceptable

• using data or text from the reports of other groups, or using cut-and-paste text from some internet source without reference, is considered to be fraud


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• Graphical representation of data and results is highly recommended , “Ein Bild sagt mehr als 100 Worte”

• All figures must have

clear axis labels indicating the quantity plotted and the units used

figure captions explaining the contents of the figure

figure numbers for reference

proper reference and explanation in the text

• figures must be large enough to see all the necessary details

• line thickness and symbol sizes must be adequate, colours often help

• the ranges used for x and y axis must be appropriate for the range of values shown

• individual measurement points should be shown by symbols

• connecting lines should usually be linear, not spline or polynomials

• where possible, add error bars


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useless

Fig 1: Variation of tropospheric NO2-column with latitude. Data from GEOSCHEM model for July 1997 [Martin et al., 2001] .

useful

often, a numerical result is expected from your experiment

all numerical results have to be given with units

checking units often helps to find errors

all results must be accompanied by error estimates

the number of digits given must make sense with the errors:

E = 13.45278456 ± 2.54378 W m-2 E = 13.5 ± 2.5 W m-2

E = 3e8 ± 2.5 W m-2 E = 31 786 209 ± 2.5 W m-2

all results should be put into context e.g.

is of expected order of magnitude

lies within 5% of the predicted value

is twice as large as expected for clean situations


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• form matters!

• use section numbering

• use clear section headers

• use numbering for equations, figures and tables

• don’t forget page numbers

• before submitting, check your report for

logic

completeness

grammar and spelling

• submit your report in a binder and not as a staple of sheets

• clearly indicate your names, date of the experiment, date of submission of report on the cover sheet


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Type of exam: Oral exam (45 minutes)

Prerequisites: Successful completion of all 4 labs

Content: 15 minutes presentation on one experiment

Questions related to the lectures

Questions to the 4 labs

Date: In August 2011, exact times TBD

Contact:

Andreas Richter Anna Serdyuchenko

Room: U-2090 Room: U-4150

Phone: 218-62103 Phone: 218- 62120

e-mail: [email protected] e-mail: [email protected]


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Experiment / Group A B C D E

Satellite Image Analysis 11.5. 22.6. 1.6.

Passive DOAS 11.5. 8.6. 1.6.

Radioactivity 25.5 22.6. 15.6.

Acoustical flow Measurements (Oceanography)

8.6. 25.5. 18.5.

FTS 22.6. 11.5. 15.6.

Cavity Ring Down Spectroscopy (CRDS)

11.5. 18.5.

Ozone Absorption Spectroscopy

8.6. 25.5 11.5.


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• Satellite Image Analysis

• Natural and man-made radioactivity in soil

• DOAS (Differential Optical Absorption Spectroscopy) measurements of stratospheric species

• Acoustic Current Measurements

• FTS Measurements

• Cavity Ring Down Measurements

• Ozone Absorption Spectroscopy

Ozone Absoprtion Spectroscopy

Very classical spectroscopy!

Three steps to measure your first ozone absorption:

1.Measure transmission spectrum of pure oxygen

- Prepare set-up (pressure, temperature and intensity stabilization)

2.Measure transmission spectrum of oxygen/ozone mixture

- prepare ozone

3.Calculate the OD from Beer-Lambert law

Taking the soil sample Experiments

◦ Test source with one gamma line – effect of geometry

◦ Test source with multiple lines – energy calibration◦ Efficiency calibration◦ Soil sample measurement

Data analysis

Natural and Man-Made Natural and Man-Made Radioactivity in SoilRadioactivity in Soil

Hardware: coaxial HPGe detector Canberra Industries (50% rel. efficiency) housed in a 10 cm Pb shielding with Cu, Cd and plastic lining

40K137Cs

210Pb

214Bi

214Pb

Source: Fischer 2008

Dana Pittauerová ([email protected])

Dr. Ahmed Qwasmeh ([email protected])◦ room: S4250, phone 62763

Determine the structure of ocean currents using data from an acoustic Doppler current profiler (ADCP) that was lowered from a research vessel to the sea floor.

Christian Mertens ([email protected])

Blue laser cavity ring-down spectroscopy

of Nitrogen Dioxide (NO2)

Three steps to measure your first absorption:

1.Align cavities with high-reflective mirrors

- align open cavity first- use closed cavity for absorption measurements

2.Measure ring-down time constants

- empty cavity first, get „offset“ τ0

- unknown amount of NO2 then, get τα

3.Calculate the NO2 concentration

satellite image in visible and infrared

enhance, display (e.g., as color image)

teach computer to automatically recognise surface type (e.g., water)


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Beam Splitter

MovingMirror

Detector

ZPD

Sunlight

FixedMirror

Voltaire V.

Fourier Transform Infrared Spectroscopy

0

0.5

1

1.5

2

700 800 900 1000 1100 1200 1300

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Fourier transformation

Wavenumber [cm-1]

Inte

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Download - Andreas Richter room U2090 Tel: 218 62103 e-mail: [email protected]

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