Advanced Building Materials


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Advanced Building Materials

  2. 2. INTRODUCTION Material science, in the guises of high-tech techniques, smart substances, intelligentinterfaces and sensory surfaces, are radically redefining the world we live in. Today’sgeneration of materials breaks new ground, many are able to anticipate and respond tochanges in the environment. Now dynamic and interactive, materials have the power tochange how the human body experiences and how the urban environment is built.Combined with the new potentials they create for industrial design and medical science,they have the capacity to transform our way of life more radically now than ever before. In nature organisms are not so structured and flexible like they are in the man madeworld. For example, the gathering of solar energy to create food, or water to nourish theplant or structural changes in plants to deal with various weather conditions all vary fromorganism to organism. Low cost or affordable construction technologies and materials are often touted as apanacea in meeting the ever growing demand for rapid housing delivery in developingeconomies. New advanced materials offer opportunities to change the way in which we constructand retrofit buildings. They give added value in terms of increased performance andfunctionality. New materials can also help address the new challenges of durability in achanging climate and help meet CO2 reduction targets.CLASSIFICATIONAdvanced building materials are in general clasified as: I. Intelligent building materials II. Interactive building materialsIntelligent building materials; are those which can sense, respond to temperature, action,stimuli etc on their own. They react as per the built in program or the commands which arepre-fed on the chip. These are more like having their own brains and acting upon their own decisions andsenses.Interactive building materials ; are those which are developed for the ease of humans butalong with also have nature to develop a sensible relationship with human world. Theserequire command or external force to perform their function. These are similar to machines like microwave, television etc. which respond to yourchoice and interest. Page | 2
  3. 3. GENERAL MATERIAL TRENDS:1) Green materials2) Materials as fashion3) Security4) modern5) Digital technology6) nano technology7) Biomimicry8) miscellaneousPROPERTIES OR BASIC TRENDS INADVANCED MATERIALS:1. Temperature (heating/cooling)2. Ventilation3. Lighting4. Illumination5. Energy conservation6. Low cost cum highly durable7. Sustainable / green8. Clean / cleanser Page | 3
  7. 7. MATERIAL LIST1. Lotusan2. Aerogel3. Titanium Dioxide Facade4. Fiber Composite Adaptive System5. Translucent Concrete6. Transparent Alluminium7. Bioconcrete8. Syndecrete9. Metamaterials10. Bulkfullerene11. Metal Foam12. Liquid Granite13. Bendable Concrete14. Magnetic Curtains15. ETFE16. Solar Shingles Page | 7
  8. 8. 1. LOTUSANThe lotus plant is a symbol of cleanliness and purity in some Eastern religions, which makessense considering that the plant essentially cleans itself. A lotus plant’s leaves stay dry even after a rainfall. Water beads on the surface andruns off like mercury. Dirt and other residue roll off with the raindrops, so the leaves lookclean even after being splashed with mud. Sto Corp. has duplicated that “lotus effect” in Lotusan, its self-cleaning siliconeexterior paint. Lotusan was introduced to Europe in 1999, and now, it’s being sold in NorthAmerica for the first time. Lotusan’s extreme resistance to water is a product of Sto technology. The coating,after it is applied, mimics the microstructure of the surface of a lotus leaf. Tiny peaks andvalleys on the surface minimize the contact area for water and dirt. As a result, the coatingis highly resistant to dirt, mold and mildew, and it offers excellent resistance to weather,chalk and UV rays.Non lotusan painted wall lotusan painted wall The new surface technology also reduces the risk of attack by microorganisms. Algaeand fungal spores are either washed off or are unable to survive on a dry and dirt-freeexterior. According to a 2002 study, the level of germs on a Lotusan surface after threeyears was 90 per cent lower than that on surface coated with a conventional paint product. Page | 8
  9. 9. With typical paints, water drops flatten and streak instead of beading and rolling offlike they do with Lotusan. Even Sto’s other silicone coatings don’t resist moisture nearly as.And since dirt rolls off with water, exteriors treated with this coating tend to retain their goodlooks. Lotusan boasts high water-vapor permeability. Lotusan is a flat finish paint available in 38 standard colors (Sto’s “classic colorcollection”) plus custom color tints. The coating can be used for new construction and recoatprojects over concrete, stucco, EIFS, and fiber cement board substrates.PRODUCT CHARACTERISTICS• Water dilutable, physiologically and ecologically safe (free from aromatic solvents)• Highly impermeable to water as soon as coating has cured• Highest water repellency achievable for coatings• Effectively reduced adhesion of dirt particles• Excellent weather-, chalk- and UV- resistance• Excellent breathability for water vapor and CO2• Increased natural protection against algae and fungal attack owing to removal of the elements fundamental to their existence, i.e. water and dirt deposits• Ideal protection against humidity and dirt, even for highly-stressed weather-exposed facades• Excellent adhesion to mineral and organic substrates• Easy application by brush, roller and airless spray• Mineral, extremely matt finish.How the lotus effect works: Sto Lotusan has a micro-structural surface whichconsiderably reduces the contact area for dirt particles and water.Combined with Stosilicone quality, this results in a super hydrophobic, water-repellent surface. Dirt particleswhich adhere only loosely, are easily carried away by raindrops.COST: According to an estimate, it costs nearly $1,500-$3,000 for an average single-story,three-bedroom home to be painted externally. The cost easily run $3,000-$5,500 in the caseof a multi-storey house. To paint a 3000 square foot home externally, nearly 15 gallons ofpaint is required. The cost of average quality paint per gallon is $25-$40. Page | 9
  10. 10. 2. AEROGEL An Aerogel is an open-celled, mesoporous, solid foam that is composed of a networkof interconnected nanostructures and that exhibits a porosity (non-solid volume) of no lessthan 50% It is a synthetic porous material derived from a gel, in which the liquid component ofthe gel has been replaced with a gas. The result is a solid with extremelylow density and thermal conductivity. It is nicknamed frozen smoke, solid smoke, solidair or blue smoke owing to its translucent nature and the way light scatters in the material;however, it feels like expanded polystyrene (styrofoam) to the touch. Aerogel was first created by Samuel Stephens Kistler in 1931, as a result of a betwith Charles Learned over who could replace the liquid in "jellies" with gas without causingshrinkage. Aerogels are produced by extracting the liquid component of a gelthrough supercritical drying. This allows the liquid to be slowly drawn off without causing thesolid matrix in the gel to collapse from capillary action, as would happen withconventional evaporation. The first aerogels were produced from silica gels. Kistlers laterwork involved aerogels based on alumina, chromia and tin dioxide. Carbon aerogels werefirst developed in the late 1980s. Aerogels are dry materials (unlike “regular” gels, which are usually wet like gelatindessert). The word aerogel refers to the fact that aerogels are derived from gels–effectivelythe solid structure of a wet gel, only with a gas or vacuum in its pores instead of liquid.PRODUCT CHARACTERSTICS: Despite its incredibly low density, aerogel is one of the most powerful materials onthe planet. It can support thousands of times its own weight, block out intense heat, coldand sound – yet it is 1,000 times less dense than glass, nearly as transparent and iscomposed of %99.8 air. The lowest-density silica-based aerogels are even lighter thanair.Despite its fragility in certain regards and its incredible lack of density, aerogel hasamazing thermal, acoustical and electrical insulation properties. Aside from its othercapabilities, aerogel also has amazing absorbing abilities. Some speculate it could be thefuture solution to oil spills. It is also being tested as a possible slow-release drug deliversystem for potential human patients. Pressing softly on an aerogel typically does not leave a mark; pressing more firmlywill leave a permanent depression. Pressing firmly enough will cause a catastrophicbreakdown in the sparse structure, causing it to shatter like glass – a property knownas friability; although more modern variations do not suffer from this. Despite the fact that itis prone to shattering, it is very strong structurally. Its impressive load bearing abilities aredue to thedendritic microstructure, in which spherical particles of average size 2–5 nm arefused together into clusters. Page | 10
  11. 11. Owing to its hygroscopic nature, aerogel feels dry and acts as a strong desiccant.Persons handling aerogel for extended periods should wear gloves to prevent theappearance of dry brittle spots on their skin. The slight color it does have is due to Rayleigh scattering of theshorter wavelengths of visible light by the nanosized dendritic structure. This causes it toappear smoky blue against dark backgrounds and yellowish against bright backgrounds. Aerogels by themselves are hydrophilic, but chemical treatment can makethem hydrophobic. If they absorb moisture they usually suffer a structural change, such ascontraction, and deteriorate, but degradation can be prevented by making themhydrophobic. Aerogels with hydrophobic interiors are less susceptible to degradation thanaerogels with only an outer hydrophobic layer, even if a crack penetrates the surface.Hydrophobic treatment facilitates processing because it allows the use of a water jet cutter.(A) Low dense,& transparent (B) High heat resistance (C) Smoky blue colour of scattered light(D) Low thermal conductivity (E) High surface area, structurally strong Page | 11
  12. 12. APPLICATION FACTS:• A single one-pound block can support half a ton of weight.• An aerogel window one inch thick has the effective insulative capacity of a ten-inch thick glass window system.KEY CHARACTERISTICS*:• Extremely low thermal conductivity : 9-12mW/mK• High porosity : >90% air• Nano-sized pores : 20-40 nanometers• High surface area : ~750m2/g• Very low tap density : 30-100kg/m3• High oil absorption capacity (DBP) : 540g/100g• Specific heat capacity : .7-1.15 kJ/(kg*K)• Variety of particle sizes : 5 microns-4mm• Surface chemistry : Completely hydrophobic• Opacity : Translucent, IR opacified and opaque *Characteristics vary depending on application, temperature and form.COMPOSITION : Aerogel is not like conventional foams, but is a special porous material with extrememicroporosity on a micron scale. It is composed of individual features only a fewnanometers in size. These are linked in a highly porous dendritic-like structure. Aerogel is asilica-based substance consisting of a loose dendritic network of the atom silicon. Aerogel is manufactured by removing the liquid from a silica alcogel andreplacing it with nothing but air, which makes up 99.8 percent of the final product.Some aerogels have a density as low as .001 grams per cubic centimeter (.0005 ounces percubic inch). Aerogel is made by high temperature and pressure-critical-point drying of a gelcomposed of colloidal silica structural units filled with solvents.RANGE OF APPLICATIONS INCLUDES: Architectural daylighting Oil and gas pipelines Coatings formulations Industrial and cryogenic plants and vessels Building insulation Outdoor gear and apparel Personal care products Page | 12
  13. 13. FORMATION OF AEROGEL Aerogels are open-cell polymers with pores less than 50 nanometers in diameter. Ina process known as sol-gel polymerization, simple molecules called monomers suspendedin solution react with one another to form a sol, or collection, of colloidal clusters. Themacromolecules become bonded and cross-linked, forming a nearly solid, transparent sol-gel. An aerogel is produced by carefully drying the sol-gel so that the fragile network doesnot collapse. Sol-gel polymerization is a bulk process with no way to control the size of the sols orthe way they come together. The structure and density of the final aerogel are dictated tosome extent by the conditions during polymerization such as temperature, pH, type ofcatalyst, and so on. But with current fabrication methods, the aerogels structure cannot becontrolled at the molecular level. Page | 13
  14. 14. NOTE Although it’s true that a typical silica aerogel could hold up to 2000 times itsweight in applied force, this only holds if the force is gently and uniformly applied. Also, keepin mind that aerogels are also very light, and 2000 times the weight of an aerogel still mightnot be very much. Additionally, most aerogels as-produced are extremely brittle and friable(that is, they tend to fragment and pulverize). But there are several ways aerogels can be made strong and even flexible, enough thataerogels can now be used as structural elements.There are four general ways to enhancethe mechanical properties of aerogels:1. Liquid-phase crosslinking2. Vapor-phase crosslinking3. Fiber reinforcing, and4. Reduced bondingWHAT ARE AEROGELS MADE OF? The term aerogel does not refer to a particular substance, but rather to a geometrywhich a substance can take on–the same way a sculpture can be made out of clay, plastic,papier-mâché, etc., aerogels can be made of a wide variety of substances, including: Silica Most of the transition metal oxides (for example, iron oxide) Most of the lanthanide and actinide metal oxides (for example, praseodymium oxide) Several main group metal oxides (for example, tin oxide) Organic polymers (such as resorcinol-formaldehyde, phenol-formaldehyde, polyacrylates, polystyrenes, polyurethanes, and epoxies) Biological polymers (such as gelatin, pectin, and agar agar) Semiconductor nanostructures (such as cadmium selenide quantum dots) Carbon Carbon nanotubes Metals (such as copper and gold) Aerogel composites, for example aerogels reinforced with polymer coatings oraerogels embedded with magnetic nanoparticles, are also prepared.VARITIES OF AEROGEL : Metal Oxide Aerogels  Nickel Oxide Aerogels  Zinc Oxide Aerogels  Alumina Aerogels (Epoxide-Assisted) Page | 14
  15. 15.  Alumina Aerogels (Alkoxide Method)  Iron Oxide Aerogels  Lanthanide Oxide Aerogels Organic and Carbon Aerogels  Organic Aerogels  Pyrolysis Silica Aerogel  Silica Aerogel (TEOS, Base-Catalyzed)  Silica Aerogel (TMOS, Base-Catalyzed)  Hydrophobic and Subcritically-Dried Silica AerogelAVAILABLE AS : “ THERMABLOK”- Aerogel, also referred to as "frozen smoke," has beendifficult to adapt to most uses because of its fragility. Thepatented Thermablok material overcomes this by using aunique fiber to suspend a proprietary formula of aerogel sothat it can be bent or compressed while stillretaining its amazing insulation properties. Now available to the building industry, just one, 3/8-inch x 1½-inch (6.25mm x 38mm) strip of Thermablok addedto each stud before hanging drywall is all that is needed totackle thermal bridging and achieve maximum R-factor value.It is installed directly to the stud edge within the wall framing,before the installation of drywall. Thermablok is easily cut tosize, and has a peel-and-stick backing for quick and simpleinstallation. As the Thermablok aerogel material is 95 percent air,and is situated between the stud and the drywall, it breaks the mechanical connection(thermal bridging) exceptionally well. Thanks to its hydrophobic properties, Thermablok will not age, mold, or mildew.Thermablok aerogel insulating material is environmentally safe and recyclable. Page | 15
  16. 16. 3. TITANIUM DIOXIDE FACADE Titanium dioxide, also known as titanium(IV) oxide or titania, is the naturallyoccurring oxide of titanium, chemical formula TiO2. When used as apigment, it iscalled titanium white, Pigment White 6, or CI 77891. Generally it comes in two differentforms, rutile and anatase.APPLICATIONS:It has a wide range of applications:1. Pigment o Titanium dioxide is the most widely used white pigment because of its brightness and very high refractive index, in which it is surpassed only by a few other materials. Approximately 4 million tons of pigmentary TiO2 are consumed annually worldwide. When deposited as a thin film, its refractive index and colour make it an excellent reflective optical coating for dielectric mirrors and some gemstones like "mystic fire topaz". TiO2 is also an effective opacifier in powder form, where it is employed as a pigment to provide whiteness and opacity to products such as paints, coatings, plastics, papers, inks, foods, medicines (i.e. pills and tablets) as well as most toothpastes. Opacity is improved by optimal sizing of the titanium dioxide particles. o In ceramic glazes titanium dioxide acts as an opacifier and seeds crystal formation. o Titanium dioxide is often used to whiten skimmed milk; this has been shown statistically to increase skimmed milks palatability.2.Sunscreen and UV absorber o In cosmetic and skin care products, titanium dioxide is used as a pigment, sunscreen and a thickener. It is also used as a tattoo pigment and in styptic pencils. Titanium dioxide is produced in varying particle sizes, oil and water dispersible, and with varying coatings for the cosmetic industry. o Titanium dioxide is found in almost every sunscreen with a physical blocker because of its high refractive index, its strong UV light absorbing capabilities and its resistance to discolouration underultraviolet light. This advantage enhances its stability and ability to protect the skin from ultraviolet light. Page | 16
  17. 17. 3. Photocatalyst o Titanium dioxide, particularly in the anatase form, is a photocatalyst under ultraviolet (UV) light. Recently it has been found that titanium dioxide, when spiked with nitrogen ions or doped with metal oxide like tungsten trioxide, is also a photocatalyst under either visible or UV light. The strong oxidative potential of the positive holes oxidizes water to create hydroxyl radicals. It can also oxidize oxygen or organic materials directly. Titanium dioxide is thus added to paints, cements, windows, tiles, or other products for its sterilizing, deodorizing and anti-fouling properties and is used as a hydrolysis catalyst. It is also used indye-sensitized solar cells, which are a type of chemical solar cell (also known as a Graetzel cell). o Titanium dioxide has potential for use in energy production: as a photocatalyst, it can carry outhydrolysis; i.e., break water into hydrogen and oxygen. Were the hydrogen collected, it could be used as a fuel. The efficiency of this process can be greatly improved by doping the oxide with carbon. Further efficiency and durability has been obtained by introducing disorder to the lattice structure of the surface layer of titanium dioxide nanocrystals, permitting infrared absorption. o Titanium dioxide can also produce electricity when in nanoparticle form. By using these nanoparticles to form the pixels of a screen, they generate electricity when transparent and under the influence of light. If subjected to electricity on the other hand, the nanoparticles blacken, forming the basic characteristics of a LCD screen. o Superhydrophilicity phenomenon for titanium dioxide coated glass exposed to sun light results in the development of self-cleaning glass and anti-fogging coatings. o TiO2 incorporated into outdoor building materials, such as paving stones in noxer blocks or paints, can substantially reduce concentrations of airborne pollutants such as volatile organic compounds and nitrogen oxides. o TiO2 offers great potential as an industrial technology for detoxification or remediation of wastewater due to several factors. a. The process occurs under ambient conditions very slowly; direct UV light exposure increases the rate of reaction. b. The formation of photocyclized intermediate products, unlike direct photolysis techniques, is avoided. c. Oxidation of the substrates to CO2 is complete. d. The photocatalyst is inexpensive and has a high turnover. e. TiO2 can be supported on suitable reactor substrates.4. Electronic data storage medium In 2010, researchers at the University of Tokyo, Japan have created a 25 terabytetitanium oxide-based disc. Page | 17
  18. 18. PRODUCT CHARACTERSTICS• This facade takes an active stance and attacks the problem of dirty air by aiming to help purify the air.• The tower pulls dirt, grease, and bacteria out of the air, producing only oxidation and water as a result.MATERIAL COMPOSITION AND ACTION:• The reaction is triggered by the use of a nano-coating of titanium dioxide on the outer skin of the project. The reaction is naturally powered by sunlight acting on the titanium dioxide during the day and supplemented by ultra violet light at night.• These UV lights are powered by energy collected through PV panels during the day.• The tower will be a glowing indigo object at night varying in intensity according to the amount of solar energy collected during the day. The indigo glow will become symbolic of the cleansing, counteracting the yellow haze that dominates the daytime hours.• The skin design is inspired by the pocketed and cellular texture of the titanium dioxide molecule (TiO2).• A series of organic cells cover the building and are tapered to naturally collect the water, a byproduct of the skins chemical reaction, and to collect and slowly release rain water.• The skin pulls off of the building on the south facades to provide natural shading and pushes into the inner skin of the north façade to maximize daylight and provide fifty percent coverage to reduce heat loss during the winter months.• The skin also floats off the building to conceal the UV lights which can be harmful to humans who are directly exposed to it, and further maximizes the building’s envelope.THE FACADE Titanium dioxide, also known as titanium(IV) oxide or titania, is the naturallyoccurring oxide of titanium, chemical formula TiO2. When used as a pigment, it iscalled titanium white, Pigment White 6, or CI 77891. Generally it comes in two differentforms, rutile and anatase. It has a wide range of applications, from paintto sunscreen to food coloring. TiO2 is a soft solid and melts at 1800 0C. It is polymorphous and it exists in threetypes of crystal structures: (a) rutile, (b) anatase and (c) brookite. Only rutile is usedcommercially.RUTILE:- has density of 4.2g/cc- is colorless (but it is used for pigmentation)- as a chemical is Dielectric- absorbs ultraviolet light Page | 18
  19. 19. - has high stability- has a pH of 7.00-8.3 when present as a solid in solution- is composed by 94% of TiO2 and Alumina- only diamond has a higher refractive index (how it bends light) than rutile.Rutile Cost: is about $10 per ton.Where big reserves of TiO2 exist:1. Southeast Canada2. Southeast USA3. Southwest Scandinavia5. Midwest and South Africa6. Mediterranean Sea7. East AustraliaTi (TITANIUM): what is it and properties:- metal (ninth most abundant element on earth)- pure metal is 99.6%- it density is 4.5g/ML- melting point, 1943 K; boiling point, 3562 K- heat of vaporization and fusion 421 kj/mol and 15.45 kj/mol respectively- specific heat 0.52 j/gK- it burns in air and it is the only metal that burns in Nitrogen.- when pure it is lustrous, white- excellent corrosion resistant- strong as steal and 45% lighter- 60% heavier than aluminum and twice as strong.- it has low module of elasticity and low coefficient of expansion- it is not magneticWhere Ti could be found?1. On meteorites and sun.2. On earth in igneous rocks.3. In ash, plants and animal bodies.APPLICATIONS:a) Pigment Titanium dioxide is the most widely used white pigment because of its brightness and very high refractive index, in which it is surpassed only by a few other materials. Approximately 4 million tons of pigmentary TiO2 are consumed annually worldwide. When deposited as a thin film, its refractive index and color make it an excellent Page | 19
  20. 20. reflective optical coating for dielectric mirrors and some gemstones like "mystic fire topaz". TiO2 is also an effective opacifier in powder form, where it is employed as a pigment to provide whiteness and opacity to products like paints, coatings, plastics, papers ,inks, foods, medicines (i.e. pills and tablets) as well as most toothpastes. In paint, it is often referred to off-handedly as "the perfect white", "the whitest white", or other similar terms. Opacity is improved by optimal sizing of the titanium dioxide particles. In ceramic glazes titanium dioxide acts as an opacifier and seeds crystal formation.b) Sunscreen and UV absorber Titanium dioxide is produced in varying particle sizes, oil and water dispersible, and with varying coatings. This pigment is used extensively in plastics and other applications for its UV resistant properties where it acts as a UV absorber, efficiently transforming destructive UV light energy into heat. Titanium dioxide is found with a physical blocker because of its high refractive index, its strong UV light absorbing capabilities and its resistance to discolouration under ultraviolet light. This advantage enhances its stability and ability to protect the from ultraviolet light.c) Photocatalyst Titanium dioxide, particularly in the anatase form, is a photocatalyst under ultraviolet (UV) light. Recently it has been found that titanium dioxide, when spiked with nitrogen ions or doped with metal oxide like tungsten trioxide, is also a photocatalyst under either visible or UV light. The strong oxidative potential of the positive holes oxidizes water to create hydroxyl radicals. It can also oxidize oxygen or organic materials directly. Titanium dioxide is thus added to paints, cements, windows, tiles, or other products for its sterilizing, deodorizing and anti-fouling properties and is used as a hydrolysis catalyst. It is also used in dye-sensitized solar cells, which are a type of chemical solar cell (also known as a Graetzel cell). The process on the surface of the titanium dioxide was called the Honda-Fujishima effect. Titanium dioxide has potential for use in energy production: as a photocatalyst, it can carry out hydrolysis; i.e., break water into hydrogen and oxygen. Were the hydrogen collected, it could be used as a fuel. The efficiency of this process can be greatly improved by doping the oxide with carbon. Further efficiency and durability has been obtained by introducing disorder to the lattice structure of the surface layer of titanium dioxide nanocrystals, permitting infrared absorption. Titanium dioxide can also produce electricity when in nanoparticle form. Using these nanoparticles to form the pixels of a screen, they generate electricity when transparent and under the influence of light. If subjected to electricity on the other hand, the nanoparticles blacken, forming the basic characteristics of a LCD screen. The super hydrophilicity phenomenon for titanium dioxide coated glass exposed to sun light resulted in the development of self-cleaning glass and anti-fogging coatings. Page | 20
  21. 21. TiO2 incorporated into outdoor building materials, such as paving stones in noxer blocks or paints, can substantially reduce concentrations of airborne pollutants such as volatile organic compounds and nitrogen oxides. TiO2 offers great potential as an industrial technology for detoxification or remediation of wastewater due to several factors.1. The process occurs under ambient conditions very slowly; direct UV light exposure increases the rate of reaction.2. The formation of photocyclized intermediate products, unlike direct photolysis techniques, is avoided.3. Oxidation of the substrates to CO2 is complete.4. The photo catalyst is inexpensive and has a high turnover.5. TiO2 can be supported on suitable reactor substrates.d ) Oxygen Sensors Even in mildly reducing atmospheres titania tends to lose oxygen and become substoichiometric. In this form the material becomes a semiconductor and the electricalresistivity of the material can be correlated to the oxygen content of the atmosphere towhich it is exposed. Hence titania can be used to sense the amount of oxygen (or reducingspecies) present in an atmosphere.e) Antimicrobial Coatings The photocatalytic activity of titania results in thin coatings of the material exhibitingself cleaning and disinfecting properties under exposure to UV radiation. These propertiesmake the material a candidate for applications such as medical devices, food preparationsurfaces, air conditioning filters, and sanitaryware surfaces. Page | 21
  22. 22. .Overview Titanium dioxide (TiO²) is a photocatalyst which exhibits strong oxidative propertywhen exposed to ultraviolet (UV)light. TiO² is able to decompose harmful organic Page | 22
  23. 23. compounds, kill bacteria and eliminate odors. TiO²’s reactivity is used in manyenvironmentally beneficial applications including water treatment and purification,atmospheric Nox(nitrogen oxide) removal and self-cleaning building façade. Titaniumdioxide is non-toxic and therefore is used in cosmetic products (sunscreens, lipsticks,toothpaste) and in pharmaceutics (pills).Technology When TiO² absorbs UV light, electrons are promoted from the valence band to theconduction band, producing holes in the valence band. The production of pairs of negative-electrons (e-) and positive-holes (h+) is called “photo-excitation”. The holes in the valenceband react with water on the titanium dioxide coating, forming hydroxyl radicals.When acontaminant in the air is adsorbed onto the TiO², the hydroxyl radical attacks thecontaminant, extracting a hydrogen atom from the contaminant. The hydroxyl radicaloxidizes the contaminant, producing water, carbon dioxide and other harmless substances.Hydroxyl radicals have much stronger oxidative power than chlorine or ozone which is usedas a sterilizer.Building Facade Applications1. Atmosphere Cleaning (Nox removal from the atmosphere)2. Deodorization (Indoor odour and Volatile Organic Compounds removal)3. Self-Cleaning (Dirt removal for exterior building facade)4. Water Treatment (Water sterilization and odour removal)5. Anti-Bacterial (Bacteria growth elimination) Page | 23
  24. 24. Atmosphere Cleaning. Page | 24
  25. 25. Comparison between a building not having TiO2 facade to that with a TiO2 facadeComparison between a coated and non coated TiO2 plate to evaluate its deodorization effect. Page | 25
  26. 26. Thin Film formation over the target surface Page | 26
  27. 27. 4. FIBRE COMPOSITE ADAPTIVE SYSTEM Fibre composite adaptive systems emulates self-organization processes in nature bydeveloping a fibre composite that can sense, actuate and hence efficiently adapt tochanging environmental conditions. Fibre composites which are anisotropic andheterogeneous offer the possibility for local variations in their material properties. Embeddedfibre optics would be used to sense multiple parameters and shape memory alloysintegrated in a fibre composite material for actuation. The definition of the geometry, bothlocally and globally would complement the adaptive functions and hence the system woulddisplay ’Integrated Functionality’.INSPIRATION: ‘Thigmo-morphogenesis’ refers to the changes in shape, structure and materialproperties of biological organisms that are produced in response to transient changes inenvironmental conditions. This property can be observed in the movement of sunflowers,bone structure and sea urchins. These are all growth movements or slow adaptations tochanges in specific conditions that occur due to the nature of the material: fibre compositetissue. Natural organisms have advanced sensing devices and actuation strategies whichare coherent morpho-mechanical systems with the ability to respond to environmentalstimulus.BIOMIMICRY Form, structure, geometry, material, and behaviour are factors which cannot beseparated from one another. For example, the veins in a leaf contribute to the overall formof the leaf, its structure and geometry. At the micro scale the fibre organization complimentsto the responsive behaviour of the leaf. The veins display an integral coherence within themultiple functions they perform due to the multiple levels of hierarchy in the materialorganization. Such level of integrated functionality is the premise of this material formulationwhich aims to integrate sensing and actuation into a fibre composite material system. Fibrecomposites which are anisotropic and heterogeneous offer the possibility for local variationsin their properties. Embedded fibre optics are used to sense multiple parameters whileshape memory alloys (SMA) are integrated in the composite material for actuation. Thedefinition of the geometry, both local and global complements the adaptive functionsproviding the system with ‘Integrated Functionality.GEOMETRY The geometry was approached from two different scales: local and global. The localgeometry emerges from the topological definition of a single cell as the smallest unit withinthe material system. The proliferation of these single cell topologies responds to veryspecific rules which govern the fusion of the local and global geometries -overall form- withthe fibre composite material. This part of the project involved the manipulation of complex Page | 27
  28. 28. geometries where digital simulation was vital. Modelling the range of different geometriesthat the system could adopt after having sensed a change in the environmental conditions,required the development of codes to generate ‘structural depth’ in the out-of planedimension; this arrangement was easily achieved through the use of corrugations where thestiffness of the structure mostly depends on the height of the ‘waves’. Varying the localheight of the corrugations would therefore lead to a structure with stiffer differentiated areaswhich ultimately contribute to the structure as a whole. Once the geometrical arrangementwas decided it was necessary to establish the strategy of ‘adaptation’ at the local level. Page | 28
  29. 29. MATERIAL COMPOSITION AND ACTION:The basic composite consists of glass fibres and a polymer matrix. The sensing function is carried out through embedded fibre optics which cansimultaneously sense multiple parameters such as strain, temperature and humidity. Theseparameters are sensed and processed as inputs through artificial neural networks. Theenvironmental and user inputs, inform the topology to dynamically adapt to one of the mostefficient configurations of the ‘multiple states of equilibrium’ it could render. The topology isdefined as a multi-layered tessellation forming a continuous surface which could havedifferentiated structural characteristics, porosity, density, illumination, self-shading and soon. The actuation is carried out through shape memory alloy strips which could alter theirshape by rearranging their micro-molecular organization between their austenitic andmartensitic states. The shape memory alloy strip is bi-stable, but a strategic proliferation ofthese strips through a rational geometry could render several permutation and combinationscreating multiple states of equilibrium, thus enabling continuous dynamic adaptation of thestructure.CONCLUSIONS The proposed fibre composite adaptive system possesses multiple organizationallevels with different assembly logics, which contribute to its emergent behaviour andintegrated functionality. An increase in the ambient temperature alters the layout of thesuture curves to open a hole through which air can circulate. Similarly the openings areclosed when there is a need to maintain a certain temperature inside the pavilion. If the windincreases or changes direction, the structure re-organizes adopting a more efficientconfiguration against the new loading conditions. In essence, form, structure, geometry, andbehaviour created a cohesive synergetic whole and constituted the most importantconsideration for the construction of the digital model. Such ambitious requirementsrequired the combination of several software packages initially intended for differentprofessional disciplines with in-house written codes such as the form finding algorithm andthe fibres growth script. The result is a system which has the potential to adapt and self-organise efficiently to transient changes in the environmental conditions, illuminating theway towards the development of smart architectures. Page | 29
  30. 30. 5. TRANSLUCENT CONCRETE Translucent concrete (also: light-transmitting concrete or liquid stone) isa concrete based building material with light - transmissive properties due to embedded lightoptical elements - usually Optical fibers. Light is conducted through the stone from one endto the other. Therefore the fibers have to go through the whole object. This results into acertain light pattern on the other surface, depending on the fiber structure. Shadows castonto one side appear as silhouettes through the material. Translucent concrete at Expo Bau 2011, München/Germany Translucent concrete is used in fine architecture as a façade material andfor cladding of interior walls. But light-transmitting concrete has also been applied to variousdesign products.FABRICATION The main idea of the smart transparent concrete is that high numerical apertureoptical fibers are directly arranged in the concrete, and the optical fiber is used as sensingelement and optical transmission element. Because that the light can transmit in the opticalfiber, different shape of smart transparent concretes can be fabricated and a certain amountof optical fibers are regularly distributed in the concrete. Plastic optical fiber is an excellentmedia to transmit light at specific wavelengths which has been widely used in illuminatingfacility or architectural appearance lighting. Several ways of producing translucent concrete do exist. But all are based on a finegrain concrete (95%) and only 5% light conducting elements that are added during castingprocess. After setting the concrete is cut to plates or stones with standard machinery forcutting stone materials. The fibers run parallel to each other, transmitting light between two surfaces of theconcrete element in which they are embedded. Thickness of the optical fibers can be variedbetween 2 µm and 2 mm to suit the particular requirements of light transmission. Optical Page | 30
  31. 31. fibers transmit light so effectively that there is virtually no loss of light conducted through thefibers; in fact, it’s even possible to see colors through the concrete. Originally, the fiber filaments were placed individually in the concrete, makingproduction time-consuming and costly. Newer, semi-automatic production processes usewoven fiber fabric instead of single filaments. Fabric and concrete are alternately insertedinto molds at intervals of approximately 2 mm to 5 mm. Smaller or thinner layers allow anincreased amount of light to pass through the concrete. Following casting, the material is cutinto panels or blocks of the specified thickness and the surface is then typically polished,resulting in finishes ranging from semi-gloss to high-gloss. The concrete mixture is made from fine materials only: it contains no coarseaggregate. The compressive strength of greater than 70 MPa (over 10,000 psi) iscomparable to that of high-strength concretes. Page | 31
  32. 32. MOUNTING Working with natural light it has to be ensured that enough light is available. Wallmounting systems need to be equipped with some form of lighting and designed to achieveuniform illumination on the full plate surface. Usually mounting systems similar to naturalstone panels are used - e.g. LUCEM uses perforated mounting with visible screws, undercutanchors with agraffes or facade anchors.HISTORY Translucent concrete has been first mentioned in a 1935 Canadian patent.[8] Butsince the development of optical glass fibers and polymer based optical fibers the rate ofinventions and developments in this field has drastically increased. There have also beeninventions that apply this concept to more technical applications like fissure detection. In theearly 1990s forms like translucent concrete products popular today with fine & layeredpatterns were developed.PROPERTIES Translucent concrete is strong enough for the uses for traditional concrete, and chemical additives can greatly increase the strength. High density concrete. Synthetic fibers added to the mix give some flexibility without losing strength. Versatile building material. Illumination. The fibres can work upto almost 20metres running length without loss of light. The prefabricated blocks are load bearing and provide the same effect with both artificial and natural light. Colors remain the same on the other end of the block.ADVANTAGE The main advantage of these products is that on large scale objects the texture is stillvisible - while the texture of finer translucent concrete becomes indistinct at distance.Further pictograms and lettering can be realized with this technology. Page | 32
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  35. 35. 6. TRANSPARENT ALLUMINIUM Transparent alluminium also called Alluminium oxynitride or ALON is atransparent polycrystalline ceramic with cubic spinel crystal structure composed ofalluminium, oxygen and nitrogen. It is currently marketed under the name ALON by SurmetCorporation. ALON is optically transparent (≥80%) in the near ultra violet, visible and nearinfrared regions of the electromagnetic spectrum. It is 4 times harder than fused silica glass,85% as hard as sapphire and nearly 15% harder than magnesium aluminate spinel. Thematerial is stable up to 1,200 °C (2,190 °F). It can be fabricated to transparent windows,plates, domes, rods, tubes and other forms using conventional ceramic powder processingtechniques. Because of its relatively light weight, optical and mechanical properties, and itsresistance to damage due to oxidation or radiation, it shows promise for use as infrared,high temperature and ballistic and blast resistant windows. Stronger than glass, various military and commercial applications for this remarkablematerial are already being tested. What was once used in the science-fiction Star Trekmovies, see-through aluminum is now something that – through test mixing with rubies,sapphires and more – is now being tried out in all kinds of ways to create transparencywhere strength is also required.PROPERTIESMechanical Young modulus 334 GPa Shear modulus 135 GPa Poisson ratio 0.24 Knoop hardness 1800 kg/mm2 (0.2 kg load) Fracture toughness 2.0 MPa·m1/2 Flexural strength 0.38–0.7 GPa Compressive strength 2.68 GPaThermal and optical Specific heat 0.781 J/(g·°C) Thermal conductivity 12.3 W/(m·°C) Thermal expansion coefficient ~4.7×10−6/°C Transparency range 200–5000 nm ALON appears to be radiation resistant and resistant to damage from various acids,bases and water. Transparent alumnium is a transparent material that was much stronger thanplexiglass. While pexiglass sheets for a 60 x 10 tank with 18,000 cubic feet of water wouldneed to be 6inches thick, a transparent aluminium sheet would need to be 1 inch thick. Page | 35
  36. 36. APPLICATIONS ALON is used in various defense and Infrared (IR) related applications suchas Recce sensor windows, specialty IR domes with different shapes such as hemispherical,hyper-hemispherical and tangent ogive domes, transparent armor, windows for lasercommunications, and in some semi-conductor related applications. Used in static-free transparent aluminum wrapping for computer parts and other electronics. It is alsobeing tested in otherwise-conventional see-through soda cans and military shielding forvehicles. Another advantage of ALON is that it is more resistant to scratches and the effect ofthe elements (think wind, sand, etc.).MANUFACTURE ALON is a polycrystalline ceramic material which can be fabricated to windows,plates, domes, rods, tubes and other forms using conventional ceramic powder processingtechniques. It is made primarily of aluminium, oxygen, and nitrogen, and can vary slightly inits components (such as varying the aluminium content from about 30% to 36%, which hasbeen reported to affect the bulk and shear moduli by only 1–2%.) The fabricated greenwareis subjected to heat treatment (densification) at elevated temperatures followedby grinding and polishing to transparency. It remains transparent until about 2100 °C. Thegrinding and polishing substantially improves the impact resistance and other mechanicalproperties of armor. Densities of 85% of the theoretical can be achieved. It is 85% as hardas sapphire and 15% harder than magnesium aluminate spinel. ALON is four times harderthan fused silica glass, thus making it useful in a wide range of armor applications. Transparent aluminum starts out as a pile of white aluminum oxynitride powder. Thatpowder gets packed into a rubber mold in the rough shape of the desired part, andsubjected to a procedure called isostatic pressing, in which the mold is compressed in atank of hydraulic fluid to 15,000 psi, which mashes the AlON into a grainy “green body.” Thegrainy structure is then fused together by heating at 2000 °C for several days. The surfaceof the resulting part is cloudy, and has to be mechanically polished to make it optically clear. Page | 36
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  38. 38. 7. BIOCONCRETE Concrete is one of the main materials used in the construction industry, from thefoundation of buildings to the structure of bridges and underground parking lots. Theproblem with traditional concrete however is the formation of cracks. This has negativeconsequences for the durability of the material. Instead of costly humans having to maintain and repair the concrete, it would be idealif the concrete would be able to heal itself. This is now possible with help of special bacteria.These bacteria are called extremophiles, because they love to live in extreme conditions. Indry concrete for example they will not only live, but they will actively produce copiousamounts of limestone. With this calcium carbonate-based material the little constructionworkers can actively repair occurring cracks in a concrete structure. This novel type of self-healing concrete will lead to enormous savings onmaintenance and repair costs. Also the sustainability of concrete will increase dramatically,because of a lower demand for natural resources such as cement. This will lead to lowerCO2 emissions and change our way of reasoning. Instead of building against nature,biological materials and processes will be integrated into traditional engineering materialsand processes.BACTERIA AS SELF HEALING AGENT: 2 Ca(CHO2)2 + 2O2 >>> 2CaO3 + 2CO2 + 2H2O Convert Food to MineralsThe bacteria acts as catalyst and Mineral precursor compound as chemical /food. Page | 38
  39. 39. BIOCEMENTATION MECHANISM Naturally, bio-mineralization process occurs at a very slow rate over geological timeslike the formation of limestone, sandstone, etc. Bioconcrete is this process, achieved at amuch shorter timescale.MICP BY UREA HYDROLYSIS In bioconcrete, the microbially induced precipitated calcium carbonate (CaCO 3) actsas the cementing agent. In MICP by urea hydrolysis, the enzyme urease, catalyse substrateurea to precipitate carbonate ions in presence of ammonium. And with the presence ofcalcium ion, CaCO3 is precipitated. There are four parameters that govern MICP:(i) the calcium concentration,(ii) the carbonate concentration,(iii) the pH of the environment and(iv) the presence of nucleation sitesPROCESSES INVOLVED IN CACO3 PRECIPITATIONA) Hydrolysis of urea S. pasteurii uses urea as an energy source producing ammonia which increases thepH of the environment and generates carbonate. Urea hydrolysis generates carbonateions at a 1:1 molar ratio,hence controlling one of the key parameters for MICP of dissolvedinorganic carbon concentration.B) Increasing alkalinity The pH of the environment has a significant effect on the specific urease activity(SUA), hence affecting carbonate speciation. The effect of pH between 6 and 8.5 isnegligible. At neutral pH, bicarbonate (HCO3-) is the dominant carbonate species rather thancarbonate (CO32-), causing a rise in pH. This increase in pH starts ammonium (NH4+) todissociate to ammonia (NH3) until equilibrium is reached. The pH of the environment isimportant as it affects carbonate speciation and CaCO3 solubility. Page | 39
  40. 40. C) Surface absorption of Ca2+ ions Ca2+ ions are supplied in the form of calcium chloride; these ions are attracted to thebacterial cell wall due to the negative charge of the solution.D) Nucleation and crystal growth Precipitation involves:(i) The development of supersaturation solution,(ii) Nucleation (the formation of new crystals) begins at the point of critical saturation and(iii) Spontaneous crystal growth on the stable nuclei. Crystals form when the solute concentration in a solvent exceeds solubility product(supersaturation). The solubility product of calcium carbonate is extremely low (3.3 x 10-9mol.L-1) at 25oC, hence as soon as Ca2+ and CO32- ion concentration exceed this, CaCO3will precipitate.Nucleation is affected by temperature, degree of supersaturation and thepresence of other surfaces. Bacterial cells themselves can act as nucleation sites for the formation of crystals.Once stable nuclei are formed they start to grow. A crystal undergoes several transitionsand their growth rate for each mineral phase or growth mechanism is directly related on thelevel of supersaturation in the solution. Supersaturation level determines the mineral type ofCaCO3 precipitated and these levels develop with hydrolysis rate. Hence, a metastable Page | 40
  41. 41. mineral phase like amorphous calcium carbonate and vaterite (spherical crystals) is formedat high supersaturation level, and they eventually dissolve and reprecipitate as a morestable calcite (rhombohedral crystals) at lower supersaturation level. However, if ametastable crystal is coated with a stable calcite a composite mineral structure is formed. Ultimately, decay in urease activity after several hours is caused by the cumulativeeffect of enzyme excretion, cell decay, wash out, encapsulation in the CaCO3 crystals andporosity. High salt concentrations or presence of toxic compounds and high temperaturesaccelerate cell lysis and loss of hydrolysing capacity.MECHANICAL PROPERTIESPhenomena occurring during biocementation:(i) coating of particles and(ii) partial infilling of void spaces between particles by CaCO3 crystals.A) Stiffness and Strength A correlation exists between CaCO3 content, dry weight and strength. The strengthobtained depends on the dry sand density, as densely packed sand requires lessbiocementation as compared to less dense sand to achieve the same strength and thepoint-to-point contact of CaCO3 crystal which bridges between 2 adjacent .The maximumunconfined compressive strength (UCS) achieved at small scale was up to 30MPa and atlarge scale was up to 12MPa. The strength mildly(i) increases with strength of the individual particles and(ii) decreases with particle size, particle pre-coating with CaCO3 and roundness of particles.Additionally,reactions that take place very quickly are soft and powder like crystals, whilenaturally limestone,etc. form slowly and are very hard. Homogenous development ofstrength is influenced by the distribution of bacteria or urease activity; as the bacteria areeither absorbed, strained /and detached during the flow and transportation through the. Fewfactors affecting this are: (i) Fluid properties like varying viscosity and density of different solutions,(ii) Cell wall characteristics like hydrophobicity, charge and appendages and(iii) Solid properties like grain size distribution, surface texture and mineralogyBACTERIAL CULTIVATIONA) Microorganism 100L bacterial suspension with S. pasteurii was cultivated under aerobic conditions ina medium containing 20g.L-1 yeast extract, 10g.L-1 NH4Cl and 10μM NiCl2. The organismswere grown to late exponential or early stationary phase, harvested and stored at 4 oC priorto use. S. pasteurii can be cultured in non-sterile environments up to 2 days with maximumlevel of contamination not exceeding 5% of the inoculum Page | 41
  42. 42. B) Protein source Maximum bacterial growth & consequently urease activity can be obtained with20gL-1 yeast extract; beyond this no significant increase can be observed. C) Catalysts The presence of 10μM Ni2+ ions in the active site of urease aids functional activity as well as the structural integrity of the enzyme thus enhancing specific urease activity. Higher concentration of Ni2+ ions cause inhibition leading to dramatic drop of urease activity. Ni2+ ions are supplied in the form of NiCl2. NaOH is used to increase the initial pH to a desirable level. Fixation solution Calcium chloride is used to immobilise the bacteria. Reagent Solution Solution of Urea and Calcium chloride in equal molar ratio mixed with water are injected to initiate the biocementation process. Aggregate Quarry uniform sand, fine to medium grained (125-250μm). Water Tap water Discussions During the biocementation process, by-product NH4Cl is produced, it is an organic salt that dissolves in water. This by-product needs to be collected and recycled after the process; or else if mingled with local water bodies or groundwater in excessive concentrations of ammonium and chlorine could lead to eutrophication and salinization respectively. ADVANTAGES: i. High crack sealing capacity ii. Less Maintenance and repairs iii. Durableiv. Prolonged service life constructions. v. Healing agent , which is bio Sustainable.vii. Good for both economy and environment. Page | 42
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  44. 44. 8. SYNDECRETE Syndecrete is an eco-friendly concrete alternative made from a wild array of recycledmaterials that includes everything from glass to old vinyl LPs. Syndecrete is a precastconcrete material as an alternative to limited or nonrenewable natural materials such aswood and stone, as well as petroleum-based synthetic solid and laminating materials.Syndecrete is an advanced cement-based composite using natural minerals and recycledmaterials as its primary ingredients. Metal shavings, plastic regrinds, recycled glass chips,and scrap wood chips are some of the postindustrial and postconsumer recycled materialsincorporated into the Syndecrete matrix. These materials are used as decorative aggregates, creating a contemporaryreinterpretation of the Italian tradition of terrazzo. Syndecrete is a solid surfacing material,which provides consistency of color, texture, and aggregate throughout. Compared with conventional concrete, it has less than half the weight with twice thecompressive strength. Syndecrete’s broad range of applications and its unique aesthetic qualitiesdifferentiates the product from other environmentally friendly building materials. Theprovision of custom Syndecrete products often initiates the use of recycled andenvironmentally friendly products to a high-end, design oriented market segment whichmight not otherwise be predisposed to seek out recycled products. Although conventionalconcrete is not a harmful building material and is less expensive, Syndecrete is a greatalternative for those who are looking to go the extra mile in term of building green. Page | 44
  45. 45. APPLICATION Offered in pre-cast pieces, Syndecretes unique aesthetic properties include integralpigmentation and aggregates mixed to create distinctive color and texture palettes. It ismore resistant to potential chipping and cracking than conventional concrete, tile and stone,and has a workability more akin to wood than cement-based products. Syndecrete can beused for a variety of interior and exterior applications and for residential and commercialprojects like tiles, tables, fireplace hearths and surrounds, flooring and a variety of customaccessories. Page | 45
  46. 46. 9. METAMATERIALS Metamaterials are artificial materials engineered to have properties that may not befound in nature. They usually gain their properties from structure rather than composition,using small in-homogeneities to create effective macroscopic behavior. The primary research in metamaterials investigates materials with negative refractiveindex. Negative refractive index materials appear to permit the creation of superlenses which can have a spatial resolution below that of the wavelength. In other work, aform of invisibility has been demonstrated at least over a narrow wave band with gradient-index materials. Although the first metamaterials wereelectromagnetic, acoustic and seismic metamaterials are also areas of active research. Metamaterials are often associated with negative refraction and this property hasgained substantial attention because of its potential for cloaking invisibility devices andmicroscopy with super-resolution. Page | 46
  47. 47. APPLICATION The application possibilities of metamaterials are found in industrial sectors likeInformation and Communication Technologies, Space and Security & Defense, but alsoapplications in Health, Energy and Environmental areas are foreseen. Examples of devices that have been realised during the past years are:> Sensors> Superlensing> Cloaking> Light emitting diodes / cavities for low-threshold lasersand these were based on controlling the wave propagation and used dynamic, re-configurable and tunable materials.CHARACTERIZATION Metamaterial properties are not only determined by their material parameters, shape,and concentration of the constituent inclusions and due to this increased complexitycharacterisation has become a science in itself. Metamaterials consist of periodic structures. An electromagnetic metamaterialaffects electromagnetic waves by having structural features smaller than the wavelength ofthe respective electromagnetic wave. In addition, if a metamaterial is to behave as ahomogeneous material accurately described by an effective refractive index, its featuresmust be much smaller than the wavelength. Photonic metamaterials, at the scale of nanometers, are being studied in order tomanipulate light at optical frequencies. Plasmonic metamaterials utilize surface plasmons,which are packets of electrical charges that collectively oscillate at the surfaces of metals atoptical frequencies.Another structure which can exhibit sub wavelength characteristics arefrequency selective surfaces (FSS) known as Artificial Magnetic Conductors(AMC) oralternately called High Impedance Surfaces (HIS). These also have inductive andcapacitive characteristics, which are directly related to its sub wavelength structure. Photonic crystals and frequency-selective surfaces such as diffraction gratings,dielectric mirrors, and optical coatings do have apparent similarities to sub wavelengthstructured metamaterials. However, these are usually considered distinct from subwavelength structures, as their features are structured for the wavelength at which theyfunction, and thus cannot be approximated as a homogeneous material. However, novel-material structures such as photonic crystals are effective withthe visible light spectrum. The middle of the visible spectrum has a wavelength ofapproximately 560 nm (for sunlight), the photonic crystal structures are generally half thissize or smaller, that is <280 nm. Page | 47
  48. 48. NEGATIVE REFRACTIVE INDEX The greatest potential of metamaterials is the possibility to create a structure with anegative refractive index, since this property is not found in any non-synthetic material.Almost all materials encountered in optics, such as glass or water, have positive values forboth permittivity (ε) and permeability (µ). However, many metals (such as silver and gold)have negative ε at visible wavelengths. A material having either (but not both) ε or µnegative is opaque to electromagnetic radiation. Although the optical properties of a transparent material are fully specified by theparameters εr and µr, refractive index n is often used in practice, which can be determinedfrom . All known non-metamaterial transparent materials possess positive εr andµr. By convention the positive square root is used for n. Negative refractive index is an important characteristic in metamaterial design andfabrication. As reverse-refraction media, these occur when both permittivity ε andpermeability µ are negative. Furthermore, this condition occurs mathematically from thevector triplet E, H and k. In ordinary, everyday materials – solid, liquid, or gas; transparent or opaque;conductor or insulator – the conventional refractive index dominates. This means thatpermittivity and permeability are both positive resulting in an ordinary index of refraction.However, metamaterials have the capability to exhibit a state where both permittivity andpermeability are negative, resulting in an extraordinary, index of negative refraction.A negative refractive index metamaterial which bends light in the wrong directionCLASSIFICATION OF ELECTROMAGNETIC METAMATERIALS1. Negative index materials Page | 48
  49. 49. In negative index metamaterials (NIM), both permittivity and permeability are negativeresulting in a negative index of refraction. Hence, because of the double negativeparameters these are also known as Double Negative Metamaterials or double negativematerials (DNG). Other terminologies for NIMs are "left-handed media", "media with anegative refractive index", and "backward-wave media", along with other nomenclatures.2. Single negative metamaterials In single negative (SNG) metamaterials either relative permittivity (εr) or relativepermeability (µr) are negative, but not both. They exhibit properties such as resonances,anomalous tunneling, transparency, and zero reflection. Like negative index materials,SNGs are innately dispersive, so their εr, µr, and refraction index n, will alter with changes infrequency.3. Electromagnetic bandgap metamaterials Electromagnetic bandgap metamaterials control the propagation of light. This isaccomplished with either a class of metamaterial known as photonic crystals (PC), oranother class known as left-handed materials (LHM). PCs can prohibit light propagationaltogether. However, both the PC and LHM are capable of allowing it to propagate incertain, designed directions, and both can be designed to have electromagnetic bandgapsat desired frequencies. In addition, metamaterials such as Photonic crystals (PC) arecomplex, periodic, materials and are considered to be electromagnetic bandgap material.4. Double positive medium Double positive mediums (DPS) do occur in nature such as naturally occurringdielectrics. Permittivity and magnetic permeability are both positive and wave propagation isin the forward direction. Artificial materials have been fabricated which have DPS, ENG, andMNG properties combined.5. Bi-isotropic and bianisotropic metamaterials Categorizing metamaterials into double or single negative, or double positive, is normallydone based on the assumption that the metamaterial has independent electric and magneticresponses described by the parameters ε and µ. Media which exhibit magneto-electriccoupling, and which are also anisotropic (which is the case for many commonly usedmetamaterial structures), are referred to as bi-anisotropic are denoted as bi-anisotropic.6. Chiral metamaterials When a metamaterial is constructed from chiral elements then it is considered to be achiral metamaterial, and the effective parameter k will be non-zero. This is a potentialsource of confusion as within the metamaterial literature there are two conflicting uses of theterms left and right-handed. The first refers to one of the two circularly polarized waveswhich are the propagating modes in chiral media. The second relates to the triplet of electricfield, magnetic field and Pointing vector which arise in negative refractive index media,which in most cases are not chiral. Page | 49
  50. 50. METAMATERIAL GEOMETRIES Typical geometries of artificial dielectrics [collin] WIRE MEDIA Artificial materials formed by electrically dense arrays of thin conducting wires wereoriginally proposed as artificial dielectrics with the effective permittivity smaller thanunity.Only recently it was realised that wire media possess strong spatial dispersion even inthe quasi-static limit. This is because metal wire lattices support propagating transverseelectromagnetic (TEM) or quasi-TEM waves along the wires. These fields of these wavesdepend on the longitudinal coordinate (along the wires) as the planewavefields. Basically, they are transmission-line modes similar to those in two-wire transmissionline or a coaxial cable. Because they behave as propagating plane waves, they propagatewith very little decay at electrically long distances, thus creating strong nonlocality in theeffective material response (strong spatial dispersion).The effective permittivity componentalong the wires reads, for electrically dense grids of thin parallel wires.Here k is the wave number in the host medium, is the effective plasma wave number, andkz is the propagation constant along the wires. The permittivity becomes very large forspecific values of the longitudinal wave and this is called strong frequency dispersion.Thisstrong frequency dispersion was utilised in the design of low-loss superlenses, includingmagnifying. TYPICAL GEOMETRIES OF WIRE MEDIA ARTIFICIAL BI-ANISOTROPIC MEDIA AND RELATED INCLUSION GEOMETRIES Reciprocal metamaterials Due to specific shapes of these particles, applied electric field induces both electric andmagnetic dipole moments. Likewise, a magnetic field produces both magnetic and electric Page | 50
  51. 51. polarizations.It can be shown that arbitrary reciprocal bi-anisotropic effect can be realisedusing composite material containing inclusions of only these two basic shapes. Chiral inclusion (left) and omega inclusion (right). Nonreciprocal bi-anisotropic metamaterials Bi-anisotropy is also possible in materials containing naturally magnetic inclusionsbiased by some external magnetic fields coupled to some metal or dielectric inclusions. Themagneto-electric coupling coefficient is a time-odd parameter proportional to the biasmagnetic field (or other external parameter that changes sign under time inversion. Therealisation of metamaterials with very unusual properties (for example, emulatingproperties of moving media in composite materials at rest) can allow the realisation ofarbitrary linear field transformations using metamaterials An inclusion shape for the realisation of artificial moving media ARTIFICIAL MAGNETICS AND RELEVANT INCLUSION GEOMETRIES Shapes of inclusions for artificial magnetic materials should be chosen carefully, so that 1) the stronger bi-anisotropy effects would be forbidden due to the geometrical symmetry and 2) among all the secondorder effects the artificial magnetism would dominate. For microwave applications, this is relatively easy as the dimensions are in the order of a millimeter, but the theory is equally valid for nanostructured metamaterials. The key to the design is to choose the shape so that induced currents form loops with a rather Page | 51
  53. 53. SOME GEOMETRIES USED TO REALIZE BACKWARD WAVES AND NEGATIVE REFRACTION.APPLICATION Biosensors Metamaterials can be used to provide more sensitive guiding modes (based onplasmon-mediated interaction between the inclusions which shows resonant excitationconditions).Surface plasmons occur at a metal/dielectric interface and are extremelysensitive to the refractive index of the dielectric medium within the penetration depth of theevanescent field. The metamaterial inclusions can be functionalized with receptorson their surface. If the matrix consists of nanoporous material it allows analytes to reach thereceptor and the refractive index will be changed upon binding. The reflection spectrumdepends on this refractive index. Superlens A superlens (or perfect lens) is a lens, which uses metamaterials to go beyond thediffraction limit. The diffraction limit is an inherent limitation in conventional optical devices orlenses. A lens consisting of a negative index metamaterial could compensate for wavedecay and could reconstruct images in the near field. In addition, both propagating andevanescent waves contribute to the resolution of the image and resolution underneath thediffraction limit will be possible. Cloaking Page | 53
  54. 54. A cloaking device is an advanced stealth technology that causes an object to be partiallyor wholly invisible to parts of the electromagnetic (EM) spectrum (at least one wavelengthof EM emissions) Scientists are using metamaterials to bend light around an object. Tags to store and process information A remote detection via high-frequency electromagnetic fields will be possible due to thecollective response of magnonic crystals at elevated frequencies. Page | 54
  55. 55. 10. BULKFULLERENE These are organic solar cells that have the potential to be low-cost and efficient solarenergy converters, with a promising energy balance. They are made of carbon-basedsemiconductors, which exhibit favourable light absorption and charge generation properties,and can be manufactured by low temperature processes such as printing from solvent-based inks, which are compatible with flexible plastic substrates or even paper. In a real device, the absorption in the photoactive blend cannot be 100%, becausethe active layer (AL) is embedded within a stack of several layers, which have differentcomplex refractive indexes. Thus, absorption can occur in some layer located between theincident medium and the AL, and reflection can happen at any interface located before thebulk of the active layer. At present, the active materials used for the fabrication of solar cells are mainlyinorganic materials, such as silicon (Si), gallium-arsenide (GaAs), cadmium-telluride(CdTe), and cadmiumindium-selenide (CIS). The power conversion efficiency for these solarcells varies from 8 to 29%. With regard to the technology used, these solar cells can bedivided into two classes. The crystalline solar cells or silicon solar cells are made of either(mono- or poly-) crystalline silicon or GaAs. About 85% of the PV market is shared by thesecrystalline solar cells. Amorphous silicon, CdTe, and CI(G)S are based on more recent thin-film technologies.COMPOSITION AND WORKING A plastic solar cell typically consists of a photoactive layer sandwiched between asubstrate covered with a transparent electrode, and a top electrode. Charges are generatedunder the influence of light in the photoactive layer. Subsequently, these charges arecollected at both electrodes. This way light is converted into electricity.The photoactive layer in organic solar cells generally contains two components. Onecomponent is an electron-donating material (easily oxidized, the donor, p-type) and theother one an electron-accepting material (easily reduced, the acceptor, n-type). The use oftwo components with different electronic levels is one of the most important design conceptsin organic solar cells. Photo-excitations in an organic semiconductor have exciton character,i.e. a photo-excitation does not result in free charges, but in a bound electron-hole pair. Byusing a combination of donor and acceptor materials, dissociation of the exciton is achievedat the interface of both materials. The process of charge separation at the interface betweendonor and acceptor after absorption of light is referred to as photo-induced charge transfer. The bulk-heterojunction solar cell,is the most photoactive solar cell these days because the interface (heterojunction) between both components is all over the bulk , in contrast to the classical (bilayer-) heterojunction. As a result of the intimate mixing, the interface where charge transfer can occur, has increased enormously. The exciton, created after the absorption of light, has to diffuse towards this charge-transfer interface for charge generation to occur. The diffusion length of the exciton in organic materials, however, is typically 10 nm or less. This means that for efficient charge generation after absorption of light, each exciton has to find a donor-acceptor interface within a few nm, otherwise it Page | 55
  56. 56. will be lost without charge generation. An intimate bi-continuous network of donor and acceptor materials in the nanometer range should suppress exciton loss prior to charge generation. Control of morphology is not only required for a large charge-generating interface and suppression of exciton loss, but also to ensure percolation pathways for both electron and hole transport to the collecting electrodes. In a bulk-heterojunction solar cell the interface between the donor (p-type) and theacceptor (n-type) material is all over the bulk. Right: The dye-sensitized solar cell. Afterabsorption of light by the N3 sensitizer, an electron is transferred to the porous TiO2 solidand via TiO2 transported to the transparent bottom electrode. The electron transfer isfollowed by reduction of the N3 sensitizer by the liquid redox electrolyte. Subsequently, theelectrolyte is reduced by the metal top electrode. The reduction of the dye followed byreduction of the electrolyte is equivalent to transport of a positive charge to the metal topelectrode In 2000 polymer:fullerene bulk-heterojunction solar cells reached power conversionefficiencies of < 1%. Improving the performance, stability, and lifetime of bulk-heterojunctionsolar cells requires more insight in the preparation, and operation of these devices.  Carrier substrate : Glass has been used as the carrier substrate because of its ease of handling , its good gas-barrier, optical, adherence, and highly insulating properties, glass is an excellent substrate, albeit for non-flexible applications only.  Transparent bottom electrode : For a solar cell (and other opto-electronic applications, as light-emitting diodes) at least one transparent electrode is required. Typically, a transparent conductive oxide (TCO) is used, deposited on the carrier substrate. A TCO should combine a high conductivity (or low sheet resistance) with a high transparency, good substrate adherence, and a low surface roughness. The latter is necessary to prevent shunting in solar cells, and the growth of dark spots in organic light-emitting diodes (LEDs). Additionally, the workfunction of the TCO should allow for a large open-circuit voltage (Voc) without introducing a collection barrier. Finally, the TCO should be stable, and not degrade the organic semiconductor.  Active layer : Creating a sharp, well-defined interface between two organic layers, both applied from solution, is only possible when the bottom organic (conductive) layer is not dissolved by the solution used to deposit the top (active) layer. Owing to Page | 56
  57. 57. its ionic character, PEDOT:PSS hardly dissolves in the aromatic solvents typically used for conjugated polymers. For stacked layers of polymers with comparable solubility characteristics, cross linking the polymer in the bottom layer before applying the top layer can prevent re-dissolving. The same procedures can also be used for stabilization of the morphology in general.The most widely used TCO in bulk- heterojunction solar cells (and other plastic electronics) is indium tin oxide (ITO), a composite oxide where indium oxide (typically > 90%) is doped with tin oxide (< 10%). Glass substrates coated with a thin ITO layer can be obtained from commercial sources. Top electrode. The top electrode is usually a metal that is thermally evaporated under high vacuum. Depending on (the application and) the LUMO level of the underlying photoactive organic, metals with low (~3 eV, such as Ca, Ba, and Yb) or moderate (~4 eV, such as Al, and Ag) workfunctions are required. For polymer fullerene bulk- heterojunction solar cells aluminum is typically used as the top electrode. Encapsulation. After all conductive and semiconductive layers are applied, the devices are typically encapsulated. Encapsulation or packaging of organic semiconductor devices is crucial to extent the device lifetime. Especially water and oxygen have to be excluded to prevent photooxidation of the conjugated polymer and conversion of the metal electrode into an oxide (or hydroxide). Mixing fullerenes into a conjugated polymer matrix has been found to suppress photo-oxidation dramatically. Apart from a gas barrier and resistance to moisture, the packaging material must fulfill several requirements, such as for heat dissipation and electrical insulation Page | 57
  58. 58. 11. METAL FOAM A metal foam is a cellular structure consisting of a solid metal, frequently aluminium,containing a large volume fraction of gas-filled pores. The pores can be sealed (closed-cell foam), or they can form an interconnected network (open-cell foam). The definingcharacteristic of metal foams is a very high porosity: typically 75–95% of the volumeconsists of void spaces. The strength of foamed metal possesses a power law relationshipto its density; i.e., a 20% dense material is more than twice as strong as a 10% densematerial. Metallic foams typically retain some physical properties of their base material. Foammade from non-flammable metal will remain non-flammable and the foam is generallyrecyclable back to its base material. Coefficient of thermal expansion will also remain similarwhile thermal conductivity will likely be reduced. Metal foam is sometimes considered a subset of cellular metallic materials in general,which also includes "metal sponges," though often the term "metal foams" is usedinterchangeably with all cellular metallic materials. Several categories of cellular metallicmaterials are distinguished, including cellular metal (metal foam with internal cells, usuallyclosed), porous metal (with closed, smoothly curved voids (pores) rather than jagged oropen voids), metallic foams (special cases of porous metals, created by bubbling gasthrough liquid metal and then letting it solidify), and metal sponges, which is essentiallyopen-cell foam where the entire space of voids is interconnected. These categories are notmutually exclusive, and there are some substances that straddle multiple categories. The Reticulated Metallic Foams offer a cost effective and ultra high performance thermal management technology that can be integrated with advanced high performance electronic, photonic devices and with many other challenging applications. The metal foam based thermal technology is generic, flexible and scaleable. It is generic in terms of its compatibility with the cooling media ranging from DI water, inert fluorocarbons, and jet fuel to air He or Ar. It is flexible it terms of its compatibility with various semiconductor devices and substrates such as Si, GaAs, and SiC, SiN not excluding many other ceramic metallic or composite materials. The metal foam based thermal technology is scaleable both in size and performance so that it could be applied to not only discrete devices but also to Hybrid Multi Chip Modules (HMCM) integrating photonic and electronic devices, and also to double sided Printed Wiring Boards (PWB) with constraining cores. The most significant benefits of the proposed technology include; elimination of as many thermal interfaces between the source of heat dissipation and the heat sink i.e. the ambient viewed as the circulating coolant in an open loop (air) or closed loop system (liquid or gas). Page | 58
  59. 59.  The advanced Integral RMF based Heat Exchanger HX technology offers significant cost, volume, weight and performance advantages relative to the state-of-art alternate approaches. Structure of metal foam and dodecahedron having 12 pentagon shaped facetsAPPLICATIONS:1. Progressive Collapse of Steel Buildings2. Biomedical3. Automotive and Aerospace4. Power Plants5. Noise Reduction6. Fire Retardant7. Seismic8. Fully recyclable and thus environmentally friendly9. High capability to absorb crash energy10. Low thermal conductivity and magnetic permeability Many metal foams are created by introducing air bubbles into molten metal. Making afoam out of molten metal is not easy, and the material is accordingly expensive. A foamingagent such as powdered titanium hydride, which decomposes into titanium and hydrogen athigh temperatures, must be used. Metal foam is a specialty material, used foraerospace, heat exchangers, and other high-performance applications. Because metal foamis stiff and light, it has often been proposed as a futuristic structural material, though it hasnot yet seriously been used as one. Some commercial metal foams include M-Pore, Porvair,Duocel, Metal Foam Korea, Metafoam and Recemat. The pores in metal foams are usuallybetween 1-8 mm in diameter, but some specialty foams have pores so small they areinvisible to the naked eye. Page | 59
  60. 60. OPEN CELL METAL FOAMS Open celled metal foams are usually replicas using open-celled polyurethane foamsas a skeleton and have a wide variety of applications including heat exchangers (compactelectronics cooling, cryogen tanks, PCM heat exchangers), energy absorption, flow diffusionand lightweight optics. Due to the high cost of the material it is most typically used inadvanced technology, aerospace, and manufacturing. Extremely fine-scale open-cell foams, with cells too small to be visible to the nakedeye, are used as high-temperature filters in the chemical industry. Metallic foams are nowadays used in the field of compact heat exchangers toincrease heat transfer at the cost of an additional pressure drop. However, their use permitsto reduce substantially the physical size of a heat exchanger, and so fabrication costs. Tomodel these materials, most works uses idealized and periodic structures or averagedmacroscopic properties.CLOSED CELL METAL FOAMS Metal foams are commonly made by injecting a gas or mixing a foamingagent (frequently TiH2) into molten metal. In order to stabilize the molten metal bubbles,high temperature foaming agents (nano- or micrometer- sized solid particles) are required.The size of the pores, or cells, is usually 1 to 8 mm. Closed-cell metal foams are primarily used as an impact-absorbing material, similarlyto the polymer foams in a bicycle helmet but for higher impact loads. Unlike many polymerfoams, metal foams remain deformed after impact and can therefore only be used once.They are light (typically 10–25% of the density of an identical non-porous alloy; commonlythose of aluminium) and stiff, and are frequently proposed as a lightweight structuralmaterial. However, they have not yet been widely used for this purpose. Closed-cell foams retain the fire resistant and recycling capability of other metallicfoams but add the ability to float in water. Page | 60
  61. 61. Metal Foam Has A Good Memory A new class of materials known as "magnetic shape-memory foams" has beendeveloped. The foam consists of a nickel-manganese-gallium alloy whose structureresembles a piece of Swiss cheese with small voids of space between thin, curvy "struts" ofmaterial. The struts have a bamboo-like grain structure that can lengthen, or strain, up to 10percent when a magnetic field is applied. Strain is the degree to which a material deformsunder load. In this instance, the force came from a magnetic field rather a physical load.Force from magnetic fields can be exerted over long range, making them advantageous formany applications. The alloy material retains its new shape when the field is turned off, butthe magnetically sensitive atomic structure returns to its original structure if the field isrotated 90 degrees--a phenomenon called "magnetic shape-memory. Traditional polycrystalline materials are not porous and exhibit near zero strains dueto mechanical constraints at the boundaries between each grain. In contrast, a single crystalexhibits a large strain as there are no internal boundaries. By introducing voids into thepolycrystalline alloy, the researchers have made a porous material that has less internalmechanical constraint and exhibits a reasonably large degree of strain. Page | 61
  62. 62. 12. LIQUID GRANITE Liquid Granite offers a real breakthrough in reducing fire risk in buildings as, unlikeconcrete, it doesnt explode at high temperatures. It can also withstand high temperaturesfor longer periods, offering valuable minutes in the case of a fire. The material is made up ofbetween 30 and 70 per cent recycled material, mainly base products from industry. It usesless than one third of the cement used in precast concrete, which also reduces its carbonfootprint. Liquid Granite is a very versatile material that can be used in a similar way toconcrete. The fact it has a high level of fire resistance means that it can be used in areaswhere fire safety is crucial, such as around power stations, and in domestic and commercialbuildings can offer added time for evacuation in case of an emergencyThe product replaces most of the cement in standard concrete with a secret formula ofproducts to change the basic properties of the material. I believe it has great potential forthe future.QUALITIES AVD VERSITALITY1. Heat2. Strength - compressive strength of upto 80N/mm2.3. Reinforcement4. Moisture5. Eco benifitsAPPLICATIONS ENGINEERED STONE Liquid Granite provides a green alternative to natural stone without compromising ondurability, looks and quality. Its special mixing and setting characteristics enable even themost complex of shapes to be cast, whilst its durability and finishes allowed to be used inareas where even the most demanding of finishes are expected STRUCTURAL CONCRETE It can be used to replace normal structural concrete and provide fire rated sections. asliquid granite does not spall in a fire situation like normal concrete introduces the possibilityof reducing the section dimensions. REFRACTORY ENVIRONMENTS Combining the robustness of with the thermal resistance of a,refractory cast able. It canalso be used to provide extremely durable flooring around furnaces etc. Page | 62
  63. 63. Liquid Granite is made from an inorganic powder, 30-70% of which is recycledindustrial waste materials. Using the same aggregates as normal concrete, it could be usedanywhere cement is but with a fraction of the carbon footprint. Page | 63