ManufacturedSubstancesinIndustry( composite materials )

Name : Nurliyana Bt. Saiful BahariClass : 4 AuroraTeachers Name :Pn. Aliah Bt. Ngah TasirIntroduction

Since the old days, human beings have been using clay, wood, stones or metals as building materials. Many of our modern technologies require materials with unsual combination of properties that cannot be met by the conventional metal alloys, ceramics, polymeric materials. Therefore, continuous research and development have been done in search of new structural materials. To fulfil the needs, these building materials must have properties like low density, strong and resistance to heat and corrosion. Today, many of such materials are created and used for various fields.

Acomposite material(also called acomposition materialor shortened tocomposite) is a material made from two or more constituent materials with significantly differentphysicalorchemical propertiesthat, when combined, produce a material with characteristics different from the individual components. The individual components remain separate and distinct within the finished structure. The new material may be preferred for many reasons: common examples include materials which are stronger, lighter, or less expensive when compared to traditional materials. More recently, researchers have also begun to actively include sensing, actuation, computation and communication into composites.Typicalcomposite materials include: Reinforced concrete Specific superconductor Fibre optic Fibre class Photochromic glassComposite materials are generally used forbuildings, bridges, and structures such as boat hulls, swimming pool panels, race car bodies,showerstalls,bathtubs, storage tanks, imitationgraniteandcultured marblesinksand countertops. The most advanced examples perform routinely on spacecraft and aircraft in demanding environments.

Type & Properties of Compsite Materials

Composite MaterialsComponentProperties of ComponentProperties of Composite

Reinforced Concrete Concrete SteelConcrete hard but brittle low tensile strenghSteel strong intensile strength expensive can corrode

stronger higher tensile strength does not corrode easily cheaper can be moulded into shape can with stand very high applied force can support very heavy load

Superconductor Cooper(ll) oxide Yttriumoxide Bariumoxide

Insulator ofelectricityConducts electricity without resistance when cooled by liquid nitrogen

Photocromic glass Glass Silver chloride or silver bromideGlass Transparent Not sensitive to lightSilver Sensitive to light Reduce refraction of light Control the amount of light passed through it auto Has the ability to change colour and become darker when exposed to ultraviolet light

Fibre Optics Glass with low refraction index Glass with high refraction index Transparent Does not reflect light rays Low material cost Reflect light rays and allow to travel along fibre Can transmit electronic data or signal,voice and image

Fibre Glass Glass Polyster PlasticGlass High density Strong but brittle Non-flexiblePolyster Plastic light flexible inflammable elastic but weak high tensile strength moulded and shaped inert to chemicals light, strong,tough non-flammable imperme able to water resilient flexible

Types & Explanation of Composite Materials ( A Closer Look)

REINFORCES CONCRETEConcrete is hard, fireproof, waterproof, comparatively cheap and easy to maintain. It is more important construction materials. The reinforces is a combination of concrete and steel.

SUPERCONDUCTOR In normal electrical conductors such as copper metal, the existence of resistance causes the loss of electrical energy as heat. Furthermore, resistance increases as temperature increases. Superconductors can conduct electricity with zero resistance when they are cooled to extremely low temperatures. Thus, superconductors conduct electricity without any loss of energy. Metals such as copper can only achieve superconductivity at a very low temperature (known as the transition temperature). This low temperature can only be achieved using liquid helium which is very expensive. When a mixture of copper (II) oxide, barium oxide and yttrium oxide is heated up, a type of ceramic with the formula Yba. This type of ceramic, known as perovkite or YBCO, can attain superconductivity at 90K. This temperature can easily be attained by using the cheaper liquid nitrogen.The metal oxides (CuO, Y2O3 and BaO) are all electrical insulators. However, when they are combined to form a composite, the composite is a superconductor that can conduct very high current over long distance without any loss of energy.

FIBRE OPTICOptical fibres are bundles of glass tubes with very small diameters. They are finer than human hair and are very flexible. Fibre optics is a composite material that can transmit electronic data or signals, voice and images on the digital format; in the form of light along the fine glass tubes at great speed. A fibre optic consists of a core of glass of higher refractive index enclosed by a cladding of lower refractive index. A light wave entering the fibre will travel along the glass tubes due to total internal reflection. In the field of telecommunications, fibre optic is used to replace copper wire in long distance telephone lines, mobile phones, video cameras and to link computers within local area networks (LAN). Fibre optic uses light instead of electrons to carry data. Fibre optic carry more data (higher transmission capacity) with less interference, has a higher chemical stability and a lower material costs compared to metal communication cables such as copper. Fibre optics can also send signals faster than metal cables and occupies less space. PHOTOCHROMIC GLASSGlass is transparent and is not sensitive to light intensity. Silver chloride or silver bromide is sensitive to light. When exposed to light, these compounds decompose to form dark silver particles.In photochromic glass, silver chloride (AgCl) or silver bromide (AgBr) is embedded into the structure of glass. Photochromic glass has the ability to change colour and become darker when exposed to ultraviolet light. This process occurs as a result of silver halide crystals within the glass clustering together to absorb and filter light. Silver halides are converted to silver and the glass darkens. The photochromic glass will automatically become clear again when the light intensity is lowered, where by silver is converted back to silver halides. Photochromic glass is used to make lenses that change from light to dark, eliminating the necessity for a separate pair of sunglasses. It is also used to make camera lens, car windshields, information display panels, light intensity meters and also optical switches. FIBRE GLASSPlastic is light (with low density), elastic, flexible, but is brittle, not very strong and inflammable. Glass is hard and strong but is brittle, heavy (with relatively high density) and has a low compressive strength. When glass fibre filaments are embedded in polyester resin (a type of plastic), fibre glass which is strong, tough, resilient, flexible with a high tensile strength is produced. It can also be easily coloured, moulded and shaped.This material can also be bent without cracking. It is also very light (low in density) and has very good strength ratio, impermeable to water and is not inflammable (does not catch fire easily).

Uses of Composite MaterialsComposite MaterialsUses

Reinforced Concrete Construction of road Rocket launching pads High-rise buildings

Superconductor Transportation Telecommunications Astronomy industry Medical field

Photochromic glass Optical lenses Glass windows

Fibre Optic Electrical cables Observe internal organs without surgery

Fibre Glass Protective apparel for astronauts and fire fighters

Reinforced Concrete :- Fibre Glass :-

Photochromic glass :- Fibre Optic :-Superconductor :-

Conclusion

ENVIRONMENTAL IMPACT REINFORCED CONCRETE :-

The environmental impact of concrete, its manufacture and applications, is complex. Some effects are harmful; others welcome. Many depend on circumstances. A major component of concrete is cement, which has its own environmental and social impacts and contributes largely to those of concrete.In spite of the harm that badly planned use of concrete can do, well-planned concrete construction can have many sustainable benefits. The cement industry is one of the primary producers of carbon dioxide, a major greenhouse gas.Concrete is used to create hard surfaces which contribute to surface runoff that may cause soil erosion, water pollution and flooding. Conversely, concrete is one of the most powerful tools for proper flood control, by means of damming, diversion, and deflection of flood waters, mud flows, and the like. Concrete can reduce the urban heat island effect, due to its high albedo. Concrete dust released by building demolition and natural disasters can be a major source of dangerous air pollution. The presence of some substances in concrete, including useful and unwanted additives, can cause health concerns due to toxicity and radioactivity. Wet concrete is highly alkaline and should always be handled with proper protective equipment. Concrete recycling is increasing in response to improved environmental awareness, legislation, and economic considerations. Concrete dustBuilding demolition and natural disasters such as earthquakes often release a large amount of concrete dust into the local atmosphere. Concrete dust was concluded to be the major source of dangerous air pollution following the Great Hanshin earthquake. Handling precautionsHandling of wet concrete must always be done with proper protective equipment. Contact with wet concrete can cause skin chemical burns due to the caustic nature of the mixture of cement and water. Indeed, the pH of fresh cement water is highly alkaline due to the presence of free potassium and sodium hydroxides in solution (pH ~ 13.5). Eyes, hands and feet must be correctly protected to avoid any direct contact with wet concrete and washed without delay if necessary.

Concrete recyclingConcrete recycling is an increasingly common method of disposing of concrete structures. Concrete debris was once routinely shipped to landfills for disposal, but recycling is increasing due to improved environmental awareness, governmental laws and economic benefits. Concrete, which must be free of trash, wood, paper and other such materials, is collected from demolition sites and put through a crushing machine, often along with asphalt, bricks and rocks. Reinforced concrete contains rebar and other metallic reinforcements, which are removed with magnets and recycled elsewhere. The remaining aggregate chunks are sorted by size. Larger chunks may go through the crusher again. Smaller pieces of concrete are used as gravel for new construction projects. Aggregate base gravel is laid down as the lowest layer in a road, with fresh concrete or asphalt placed over it.

Toxic and radioactive contaminationThe presence of some substances in concrete, including useful and unwanted additives, can cause health concerns. Natural radioactive elements (K, U, Th, and Rn) can be present in various concentration in concrete dwellings, depending on the source of the raw materials used. For example, some stones naturally emit Radon, and Uranium was once common in mine refuse. Toxic substances may also be unintentionally used as the result of contamination from a nuclear accident. Dust from rubble or broken concrete upon demolition or crumbling may cause serious health concerns depending also on what had been incorporated in the concrete.

FIBREGLASS :-Fiberglass is a man-made mineral fiber that is widely used in America. First produced in the 1920's, fiberglass became a popular substitute for asbestos in the 1950's when some of the deleterious health effects from asbestos were first becoming apparent. Due to the similarity in shape between the fiberglass and the asbestos fibers, fiberglass was able to effectively replace asbestos in many applications such as in electrical, thermal, and acoustic insulation and in adding structural reinforcement and heat resistance to a material. The similarities to asbestos, which have allowed fiberglass to be so versatile, are also sources of concern for some who suggest that fiberglass may also exhibit similar deleterious health effects. There are three main types of fiberglass. Each type has different physical dimensions and properties which effect the suitability for specific applications and may also impact human health in different ways. These types are continuous fibers (used in electrical insulation, cement and plastics reinforcement), insulation wool (for thermal and acoustic insulation), and special purpose fibers (used for heat resistance and light-weight materials). There is currently a great deal of debate concerning the health effects of fiberglass. It is, however, agreed that fiberglass is an irritant. Skin irritation is generally associated with thick fibers which can be found in insulation wools and filamentous glass. Fiberglass may also cause irritation of the eyes and throat. If the exposure is sufficient, fiberglass may produce irritation dermatitis and difficulty in breathing, which will go away once exposure has ceased. FIBRE OPTICSFor most people, optical fibers are made "special" by what is inside themthe complex optical structures that enable them to preserve polarization in sensors, harness high levels of pump energy in fiber lasers, or even the advanced core chemistries that make them resistant to hydrogen downhole, photo-darkening, or ionizing radiation. The odds of going blind by looking into the broken end of an optical fiber are virtually nil, since the broken surface tends to scatter the light coming through it. However, it is possible for you to suffer injury by mishandling polished optical fibers, but only under certain circumstances, including: 1. The light source must be high-powered. Only the more powerful lasers are strong enough to cause injury. For example, some Cable TV lasers are powerful enough to do damage. 2. The beam of light exiting the fiber must be narrow.

PHOTOCHROMIC GLASSThe major environmental impact of glass production is caused by atmospheric emissions from melting activities:The combustion of natural gas/fuel oil and the decomposition of raw materials during the melting lead to the emission of CO2. This is the only greenhouse gas emitted during the production of glass. Sulphur dioxide (SO2) from the fuel and/or from decomposition of sulphate in the batch materials can contribute to acidification and formation of SMOG. Nitrogen oxides (NOx) due to the high melting temperatures and in some cases due to decomposition of nitrogen compounds in the batch materials also contribute to acidification. Evaporation from the molten glass and raw materials can cause release of particles in the atmosphere.Other environmental issues are water pollution, the use of non renewable natural raw materials such as sand and minerals, production of solid waste and emission of volatile organic compounds (used in production of mirrors and coatings).Although a lot has already been achieved, further reductions in emissions of SO2, dust particles, NOx and CO2 are still the main environmental objectives for our flat glass activities. Minimising and controlling these emissions in an integrated way is a complex matter. The development of environmental techniques is still ongoing, and AGC Glass Europe actively participates in the dynamic process of developing new techniques. Most of these technologies, however, have disadvantages as well as advantages. For example: Switching from heavy fuel to natural gas reduces CO2 and SO2, but increases NOx. Some technologies that reduce NOx can cause an increase in CO2 when extra energy input is needed. Technologies that reduce SO2 can produce non-recyclable waste. Some technologies for reducing SO2 are not compatible with end-of-pipe de-NOx technologies. Some technologies can affect the lifetime of the furnace or the quality of the glass.

CONTENTS Introduction Types & Properties Explanations ( Closer Look ) Uses of Composite Materials Environmental Impacts References Conclusion

REFERENCES https://en.wikipedia.org/wiki/Environmental_impact_of_concrete http://www.agc-glass.eu/English/Homepage/Our-Values/Environment/Environmental-Report-2014/Environmental-Impact/page.aspx/1656 http://ecmweb.com/content/dont-ignore-hazards-associated-fiber-optics https://www.einstein.yu.edu/administration/environmental-health-safety/industrial-hygiene/fiberglass.aspx https://en.wikipedia.org/wiki/Composite_material