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Ultralight Material
Ultralight materials are solids with a density of less than 10 mg/cm3, including silica aerogels, carbon nanotube aerogels, aerographite, metallic foams, polymeric foams, and metallic microlattices. The density of air is about 1.275 mg/cm3, which means that the air in the pores contributes significantly to the density of these materials in atmospheric conditions. They can be classified by production method as aerogels, stochastic foams, and structured cellular materials. Properties Ultralight materials are solids with a density of less than 10 mg/cm3. Ultralight material is defined by its cellular arrangement and its stiffness and strength that make up its solid constituent. They include silica aerogels, carbon nanotube aerogels, aero graphite, metallic foams, polymeric foams, and metallic micro lattices. Ultralight materials are produced to have the strength of bulk-scaled properties at a micro-size. Also, they are designed to not compress even under extreme pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerogel
Aerogels are a class of synthetic porous ultralight material derived from a gel, in which the liquid component for the gel has been replaced with a gas, without significant collapse of the gel structure. The result is a solid with extremely low density and extremely low thermal conductivity. Aerogels can be made from a variety of chemical compounds. Silica aerogels feel like fragile expanded polystyrene to the touch, while some polymer-based aerogels feel like rigid foams. The first documented example of an aerogel was created by Samuel Stephens Kistler in 1931, as a result of a bet with Charles Learned over who could replace the liquid in "jellies" with gas without causing shrinkage. Aerogels are produced by extracting the liquid component of a gel through supercritical drying or freeze-drying. This allows the liquid to be slowly dried off without causing the solid matrix in the gel to collapse from capillary action, as would happen with conventional evaporation. The first aer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Nanotube
A scanning tunneling microscopy image of a single-walled carbon nanotube Rotating single-walled zigzag carbon nanotube A carbon nanotube (CNT) is a tube made of carbon with diameters typically measured in nanometers. ''Single-wall carbon nanotubes'' (''SWCNTs'') are one of the allotropes of carbon, intermediate between fullerene cages and flat graphene, with diameters in the range of a nanometre. Although not made this way, single-wall carbon nanotubes can be idealized as cutouts from a two-dimensional Hexagonal tiling, hexagonal lattice of carbon atoms rolled up along one of the Bravais lattice vectors of the hexagonal lattice to form a hollow cylinder. In this construction, periodic boundary conditions are imposed over the length of this roll-up vector to yield a helical lattice of seamlessly bonded carbon atoms on the cylinder surface. ''Multi-wall carbon nanotubes'' (''MWCNTs'') consisting of nested single-wall carbon nanotubes weakly bound together by van der Waals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerographite
Aerographite is a synthetic foam consisting of a porous interconnected network of tubular carbon. With a density of 180 g/m3 it is one of the lightest structural materials ever created. It was developed jointly by a team of researchers at the University of Kiel and the Technical University of Hamburg in Germany, and was first reported in a scientific journal in June 2012. Structure and properties Aerographite is a black freestanding material that can be produced in various shapes occupying a volume of up to several cubic centimeters. It consists of a seamless interconnected network of carbon tubes that have micron-scale diameters and a wall thickness of about 15 nm. Because of the relatively lower curvature and larger wall thickness, these walls differ from the graphene-like shells of carbon nanotubes and resemble vitreous carbon in their properties. These walls are often discontinuous and contain wrinkled areas that improve the elastic properties of aerographite. The c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metallic Foam
image:Alvéoles 4.jpg, Regular foamed aluminium A metal foam is a cellular structure consisting of a solid metal (frequently aluminium) with gas-filled Porosity, pores comprising a large portion of the volume. The pores can be sealed (closed-cell foam) or interconnected (open-cell foam). The defining characteristic of metal foams is a high porosity: typically only 5–25% of the volume is the base metal. The strength of the material is due to the square–cube law. Metal foams typically retain some physical property, physical properties of their base material. Foam made from non-flammable metal remains non-flammable and can generally be recycled as the base material. Its coefficient of thermal expansion is similar while thermal conductivity is likely reduced. Definitions Open-cell Open-celled metal foam, also called metal sponge, can be used in heat exchangers (compact computer cooling, electronics cooling, cryogenics, cryogen tanks, phase change material, PCM heat exchanger ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymeric Foam
A polymeric foam is a foam, in liquid or solidified form, formed from polymers. Examples include: * Ethylene-vinyl acetate (EVA) foam, the copolymers of ethylene and vinyl acetate; also referred to as polyethylene-vinyl acetate (PEVA) * Low-density polyethylene (LDPE) foam, first grade of polyethylene (PE) * Nitrile rubber (NBR) foam, the copolymers of acrylonitrile (ACN) and butadiene * Polychloroprene foam or Neoprene * Polyimide foam * Polypropylene (PP) foam, including expanded polypropylene (EPP) and polypropylene paper (PPP) * Polystyrene (PS) foam, including expanded polystyrene (EPS), extruded polystyrene foam (XPS) and sometimes polystyrene paper (PSP) ** Styrofoam, including extruded polystyrene foam (XPS) and sometimes expanded polystyrene (EPS) * Polyurethane (PU) foam ** LRPu low-resilience polyurethane ** Memory foam ** Sorbothane *Polyethylene foam, as used in PEF rod * Polyvinyl chloride (PVC) foam ** Closed-cell PVC foamboard * Silicone foam * Microcellular foam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metallic Microlattice
A metallic microlattice is a synthetic porous metallic material consisting of an ultra-light metal foam. With a density as low as 0.99 mg/cm3 (0.00561 lb/ft3), it is one of the lightest structural materials known to science. It was developed by a team of scientists from California-based HRL Laboratories, in collaboration with researchers at University of California, Irvine and Caltech, and was first announced in November 2011. The prototype samples were made from a nickel-phosphorus alloy. In 2012, the microlattice prototype was declared one of 10 World-Changing Innovations by ''Popular Mechanics''. Metallic microlattice technology has numerous potential applications in automotive and aeronautical engineering. A detailed comparative review study among other types of metallic lattice structures showed them to be beneficial for light-weighting purposes but expensive to manufacture. Synthesis To produce their metallic microlattice, the HRL/UCI/Caltech team first prepared a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Density Of Air
The density of air or atmospheric density, denoted '' ρ'', is the mass per unit volume of Earth's atmosphere. Air density, like air pressure, decreases with increasing altitude. It also changes with variation in atmospheric pressure, temperature and humidity. At 101.325 kPa (abs) and 20 °C (68 °F), air has a density of approximately , according to the International Standard Atmosphere (ISA). At 101.325kPa (abs) and , air has a density of approximately , which is about that of water, according to the International Standard Atmosphere (ISA). Pure liquid water is . Air density is a property used in many branches of science, engineering, and industry, including aeronautics;Olson, Wayne M. (2000) AFFTC-TIH-99-01, Aircraft Performance FlightICAO, Manual of the ICAO Standard Atmosphere (extended to 80 kilometres (262 500 feet)), Doc 7488-CD, Third Edition, 1993, .Grigorie, T.L., Dinca, L., Corcau J-I. and Grigorie, O. (2010) Aircrafts' Altitude Measurement Using Pressure Information:Ba ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerogel
Aerogels are a class of synthetic porous ultralight material derived from a gel, in which the liquid component for the gel has been replaced with a gas, without significant collapse of the gel structure. The result is a solid with extremely low density and extremely low thermal conductivity. Aerogels can be made from a variety of chemical compounds. Silica aerogels feel like fragile expanded polystyrene to the touch, while some polymer-based aerogels feel like rigid foams. The first documented example of an aerogel was created by Samuel Stephens Kistler in 1931, as a result of a bet with Charles Learned over who could replace the liquid in "jellies" with gas without causing shrinkage. Aerogels are produced by extracting the liquid component of a gel through supercritical drying or freeze-drying. This allows the liquid to be slowly dried off without causing the solid matrix in the gel to collapse from capillary action, as would happen with conventional evaporation. The first aer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aerographite
Aerographite is a synthetic foam consisting of a porous interconnected network of tubular carbon. With a density of 180 g/m3 it is one of the lightest structural materials ever created. It was developed jointly by a team of researchers at the University of Kiel and the Technical University of Hamburg in Germany, and was first reported in a scientific journal in June 2012. Structure and properties Aerographite is a black freestanding material that can be produced in various shapes occupying a volume of up to several cubic centimeters. It consists of a seamless interconnected network of carbon tubes that have micron-scale diameters and a wall thickness of about 15 nm. Because of the relatively lower curvature and larger wall thickness, these walls differ from the graphene-like shells of carbon nanotubes and resemble vitreous carbon in their properties. These walls are often discontinuous and contain wrinkled areas that improve the elastic properties of aerographite. The c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metal Foam
Regular foamed aluminium A metal foam is a cellular structure consisting of a solid metal (frequently aluminium) with gas-filled pores comprising a large portion of the volume. The pores can be sealed (closed-cell foam) or interconnected (open-cell foam). The defining characteristic of metal foams is a high porosity: typically only 5–25% of the volume is the base metal. The strength of the material is due to the square–cube law. Metal foams typically retain some physical properties of their base material. Foam made from non-flammable metal remains non-flammable and can generally be recycled as the base material. Its coefficient of thermal expansion is similar while thermal conductivity is likely reduced. Definitions Open-cell Open-celled metal foam, also called metal sponge, can be used in heat exchangers (compact electronics cooling, cryogen tanks, PCM heat exchangers), energy absorption, flow diffusion, scrubbers, flame arrestors, and lightweight optics. The hig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Field
A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to the magnetic field. A permanent magnet's magnetic field pulls on ferromagnetic materials such as iron, and attracts or repels other magnets. In addition, a nonuniform magnetic field exerts minuscule forces on "nonmagnetic" materials by three other magnetic effects: paramagnetism, diamagnetism, and antiferromagnetism, although these forces are usually so small they can only be detected by laboratory equipment. Magnetic fields surround magnetized materials, and are created by electric currents such as those used in electromagnets, and by electric fields varying in time. Since both strength and direction of a magnetic field may vary with location, it is described mathematically by a function assigning a vector to each point of space, cal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catechol
Catechol ( or ), also known as pyrocatechol or 1,2-dihydroxybenzene, is a toxic organic compound with the molecular formula . It is the ''ortho'' isomer of the three isomeric benzenediols. This colorless compound occurs naturally in trace amounts. It was first discovered by destructive distillation of the plant extract catechin. About 20,000 tonnes of catechol are now synthetically produced annually as a commodity organic chemical, mainly as a precursor to pesticides, flavors, and fragrances. Catechol occurs as feathery white crystals that are very rapidly soluble in water. Isolation and synthesis Catechol was first isolated in 1839 by Edgar Hugo Emil Reinsch (1809–1884) by distilling it from the solid tannic preparation catechin, which is the residuum of catechu, the boiled or concentrated juice of ''Mimosa catechu'' (''Acacia catechu''). Upon heating catechin above its decomposition point, a substance that Reinsch first named ''Brenz-Katechusäure'' (burned catechu acid) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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