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Sand Reinforced Polyester Composite
Sand reinforced polyester composites (SPCs), are building materials with sand acting as reinforcement in the composite. Pioneers in using sand reinforced composites include German business men Gerhard Dust and Gunther Plötner, who made sand reinforced composite bricks with polyester resin and hardener to provide emergency relief housing for those affected by the 2010 earthquake in Haiti. Sand was used in the composites because of its abundance and ease in obtaining. Composition The composition of sand is highly variable depending on the origin of the sand. The most common material found in non-tropical, coastal, and inland sand is silica usually in the form of quartz – which is considerably hard and one of the most common minerals resistant to weathering. Preparation * Drying sand * Mixing with alternate material(s) * Adding a hardener to the mixture (such as methyl ethyl ketone peroxide) * Pouring mixture into mold and drying * Releasing from mold and smoothing Prope ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Building Material
Building material is material used for construction. Many naturally occurring substances, such as clay, rocks, sand, wood, and even twigs and leaves, have been used to construct buildings and other structures, like bridges. Apart from naturally occurring materials, many man-made products are in use, some more and some less synthetic. The manufacturing of building materials is an established industry in many countries and the use of these materials is typically segmented into specific specialty trades, such as carpentry, insulation, plumbing, and roofing work. They provide the make-up of habitats and structures including homes. The total cost of building materials In history, there are trends in building materials from being natural to becoming more human-made and composite; biodegradable to imperishable; indigenous (local) to being transported globally; repairable to disposable; chosen for increased levels of fire-safety, and improved seismic resistance. These trends t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methyl Ethyl Ketone Peroxide
Methyl ethyl ketone peroxide (MEKP) is an organic peroxide with the formula CH3)(C2H5)C(O2H)sub>2O2. MEKP is a colorless oily liquid. It is widely used in vulcanization (crosslinking) of polymers. It is derived from the reaction of methyl ethyl ketone and hydrogen peroxide under acidic conditions. Several products result from this reaction including a cyclic dimer. The linear dimer, the topic of this article, is the most prevalent. and this is the form that is typically quoted in the commercially available material. Solutions of 30 to 40% MEKP are used in industry and by hobbyists as catalyst to initiate the crosslinking of unsaturated polyester resins used in fiberglass, and casting. For this application, MEKP often is dissolved in a phlegmatizer such as dimethyl phthalate, cyclohexane peroxide, or to reduce sensitivity to shock. Benzoyl peroxide can be used for the same purpose. Safety Whereas acetone peroxide is a white powder at STP STP may refer to: Places * São ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vickers Hardness Test
The Vickers hardness test was developed in 1921 by Robert L. Smith and George E. Sandland at Vickers Ltd as an alternative to the Brinell scale, Brinell method to measure the hardness of materials. The Vickers test is often easier to use than other hardness tests since the required calculations are independent of the size of the indenter, and the indenter can be used for all materials irrespective of hardness. The basic principle, as with all common measures of hardness, is to observe a material's ability to resist plastic deformation from a standard source. The Vickers test can be used for all metals and has one of the widest scales among hardness tests. The unit of hardness given by the test is known as the Vickers Pyramid Number (HV) or Diamond Pyramid Hardness (DPH). The hardness number can be converted into units of pascal (unit), pascals, but should not be confused with pressure, which uses the same units. The hardness number is determined by the load over the surface area ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hardness
In materials science, hardness (antonym: softness) is a measure of the resistance to plastic deformation, such as an indentation (over an area) or a scratch (linear), induced mechanically either by Pressing (metalworking), pressing or abrasion (mechanical), abrasion. In general, different materials differ in their hardness; for example hard metals such as titanium and beryllium are harder than soft metals such as sodium and metallic tin, or wood and common plastics. Macroscopic hardness is generally characterized by strong intermolecular bonds, but the behavior of solid materials under force is complex; therefore, hardness can be measured in different ways, such as scratch hardness, indentation hardness, and rebound hardness. Hardness is dependent on ductility, elasticity (physics), elastic stiffness, plasticity (physics), plasticity, deformation (mechanics), strain, strength of materials, strength, toughness, viscoelasticity, and viscosity. Common examples of hard matter are cer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brittle
A material is brittle if, when subjected to stress, it fractures with little elastic deformation and without significant plastic deformation. Brittle materials absorb relatively little energy prior to fracture, even those of high strength. Breaking is often accompanied by a sharp snapping sound. When used in materials science, it is generally applied to materials that fail when there is little or no plastic deformation before failure. One proof is to match the broken halves, which should fit exactly since no plastic deformation has occurred. Brittleness in different materials Polymers Mechanical characteristics of polymers can be sensitive to temperature changes near room temperatures. For example, poly(methyl methacrylate) is extremely brittle at temperature 4˚C, but experiences increased ductility with increased temperature. Amorphous polymers are polymers that can behave differently at different temperatures. They may behave like a glass at low temperatures (the gla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weight Percent
In science and engineering, the weight of an object is a quantity associated with the gravitational force exerted on the object by other objects in its environment, although there is some variation and debate as to the exact definition. Some standard textbooks define weight as a vector quantity, the gravitational force acting on the object. Others define weight as a scalar quantity, the magnitude of the gravitational force. Yet others define it as the magnitude of the reaction force exerted on a body by mechanisms that counteract the effects of gravity: the weight is the quantity that is measured by, for example, a spring scale. Thus, in a state of free fall, the weight would be zero. In this sense of weight, terrestrial objects can be weightless: so if one ignores air resistance, one could say the legendary apple falling from the tree, on its way to meet the ground near Isaac Newton, was weightless. The unit of measurement for weight is that of force, which in the International ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flexural Strength
Flexural strength, also known as modulus of rupture, or bend strength, or transverse rupture strength is a material property, defined as the Stress (mechanics), stress in a material just before it Yield (engineering), yields in a flexure test. The transverse bending test is most frequently employed, in which a specimen having either a circular or rectangular cross-section is bent until fracture or yielding using a three-point flexural test technique. The flexural strength represents the highest stress experienced within the material at its moment of yield. It is measured in terms of stress, here given the symbol \sigma. Introduction When an object is formed of a single material, like a wooden beam or a steel rod, is bent (Fig. 1), it experiences a range of stresses across its depth (Fig. 2). At the edge of the object on the inside of the bend (concave face) the stress will be at its maximum compressive stress value. At the outside of the bend (convex face) the stress will b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compression Strength
In mechanics, compressive strength (or compression strength) is the capacity of a material or structure to withstand loads tending to reduce size (compression). It is opposed to ''tensile strength'' which withstands loads tending to elongate, resisting tension (being pulled apart). In the study of strength of materials, compressive strength, tensile strength, and shear strength can be analyzed independently. Some materials fracture at their compressive strength limit; others deform irreversibly, so a given amount of deformation may be considered as the limit for compressive load. Compressive strength is a key value for design of structures. Compressive strength is often measured on a universal testing machine. Measurements of compressive strength are affected by the specific test method and conditions of measurement. Compressive strengths are usually reported in relationship to a specific technical standard. Introduction When a specimen of material is loaded in such a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrophobic
In chemistry, hydrophobicity is the chemical property of a molecule (called a hydrophobe) that is seemingly repelled from a mass of water. In contrast, hydrophiles are attracted to water. Hydrophobic molecules tend to be nonpolar and, thus, prefer other neutral molecules and nonpolar solvents. Because water molecules are polar, hydrophobes do not dissolve well among them. Hydrophobic molecules in water often cluster together, forming micelles. Water on hydrophobic surfaces will exhibit a high contact angle. Examples of hydrophobic molecules include the alkanes, oils, fats, and greasy substances in general. Hydrophobic materials are used for oil removal from water, the management of oil spills, and chemical separation processes to remove non-polar substances from polar compounds. The term ''hydrophobic''—which comes from the Ancient Greek (), "having a fear of water", constructed Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quartz
Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of Silicon dioxide, SiO2. Quartz is, therefore, classified structurally as a Silicate mineral#Tectosilicates, framework silicate mineral and compositionally as an oxide mineral. Quartz is the second most abundant mineral in Earth's continental crust, behind feldspar. Quartz exists in two forms, the normal α-quartz and the high-temperature β-quartz, both of which are chiral. The transformation from α-quartz to β-quartz takes place abruptly at . Since the transformation is accompanied by a significant change in volume, it can easily induce microfracturing of ceramics or rocks passing through this temperature threshold. There are many different varieties of quartz, several of which are classifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sand
Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is usually defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class of soil or soil type; i.e., a soil containing more than 85 percent sand-sized particles by mass. The composition of sand varies, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal settings is silica (silicon dioxide, or SiO2), usually in the form of quartz. Calcium carbonate is the second most common type of sand. One such example of this is aragonite, which has been created over the past 500million years by various forms of life, such as coral and shellfish. It is the primary form of sand apparent in areas where reefs have dominated the ecosystem for millions of years, as in the Caribbean. Somewhat more rarely, sand may be composed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silica
Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , commonly found in nature as quartz. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and abundant families of materials, existing as a compound of several minerals and as a synthetic product. Examples include fused quartz, fumed silica, opal, and aerogels. It is used in structural materials, microelectronics, and as components in the food and pharmaceutical industries. All forms are white or colorless, although impure samples can be colored. Silicon dioxide is a common fundamental constituent of glass. Structure In the majority of silicon dioxides, the silicon atom shows Tetrahedral molecular geometry, tetrahedral coordination, with four oxygen atoms surrounding a central Si atomsee 3-D Unit Cell. Thus, SiO2 forms 3-dimensional network solids in which each silicon atom is covalently bonded in a tetrahedral manner to 4 oxygen atoms. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
