"expressed as The second consistency condition above can be derived by noting that These relations can then be substituted into the consistency condition for isotropic incompressible hyperelastic materials. Hyperelastic material A hyperelastic or green elastic material is a type of constitutive model for ideally elastic material for which the stress–strain relationship derives from a strain energy density function. The hyperelastic material is a special case of a Cauchy elastic material. For many materials, linear elastic models do not accurately describe the observed material behaviour. The most common example of this kind of material is rubber, whose stress-strain relationship can be"
"Sulfur vulcanization Sulfur vulcanization or sulfur vulcanisation is a chemical process for converting natural rubber or related polymers into more durable materials by heating them with sulfur or other equivalent curatives or accelerators. Sulfur forms cross-links (bridges) between sections of polymer chain which results in increased rigidity and durability, as well as other changes in the mechanical and electronic properties of the material. A vast array of products are made with vulcanized rubber, including tires, shoe soles, hoses, and conveyor belts. The term is derived from Vulcan, the Roman god of fire. The main polymers subjected to sulfur vulcanization are"
"Vulcanized fibre Vulcanized fibre is a laminated plastic composed of only cellulose. The material is a tough, resilient, hornlike material that is lighter than aluminium, tougher than leather, and stiffer than most thermoplastics. The newer wood-laminating grade of vulcanized fibre is used to strengthen wood laminations used in skis, skateboards, support beams and as a sub-laminate under thin wood veneers. A product very similar to vulcanized fibre is leatheroid. Leatheroid, however, is made using a different chemical process. The British patent for vulcanized fibre was obtained in 1859 by the Englishman Thomas Taylor. He gained the patent after the introduction"
"Vulcanization Vulcanization (British: vulcanisation) is a chemical process used to harden rubber. Vulcanization traditionally referred to the treatment of natural rubber with sulfur and this remains the most common example, however the term has also grown to include the hardening of other (synthetic) rubbers via various means. Examples include silicone rubber via room temperature vulcanizing and chloroprene rubber (neoprene) using metal oxides. Vulcanisation can therefore be defined as the curing of elastomers; with the terms 'vulcanization' and 'curing' sometimes used interchangeably in this context. It works by forming cross-links between sections of polymer chain which results in increased rigidity and"
"durability, as well as other changes in the mechanical and electronic properties of the material. Vulcanization, in common with the curing of other thermosetting polymers, is generally irreversible. The word vulcanisation is derived from Vulcan, the Roman god of fire. In contrast with thermoplastic processes (the melt-freeze process that characterize the behavior of most modern polymers), vulcanization, in common with the curing of other thermosetting polymers, is generally irreversible. Five types of curing systems are in common use: By far the most common vulcanizing methods depend on sulfur. Sulfur, by itself, is a slow vulcanizing agent and does not vulcanize"
"vulcanization. The sulfur chains attach themselves to the ""allylic"" carbon atoms, which are adjacent to C=C linkages. Vulcanization is a step in the processing of several classes of rubbers, including polychloroprene (Neoprene), styrene-butadiene, and polyisoprene, which is chemically similar to natural rubber. Charles Goodyear's discovery of vulcanization, involving the heating of polyisoprene with sulfur, was revolutionary because it converted a sticky and almost useless material into an elastomer which could be fabricated into useful products. In addition to water and ammonia, the clouds in the atmospheres of the gas giant planets contain ammonium sulfides. The reddish-brownish clouds are attributed to"
"properties. It offers high tear and tensile strength, while in the thinner thicknesses allowing flexibility to conform to curves and bends. In thicker thicknesses, it can be moulded to shape with steam and pressure. One application for vulcanized fibre that attests to its physical strength is that it is the preferred material for heavy sanding discs. The electrical properties exhibited by vulcanized fibre are high insulating value, and arc and track resistance with service temperature of up to 110 to 120°C. Vulcanized fibre shows high resistance to penetration by most organic solvents, oils, and petroleum derivatives. Vulcanized fibre Vulcanized fibre"
"polyisoprene (natural rubber, NR), polybutadiene rubber (BR) and styrene-butadiene rubber (SBR), all of which are rich in unsaturated groups. Together these have a wide range of applications of which vehicle tires are perhaps the most important example. Several other specialty rubbers may also be vulcanised, such as nitrile rubber (NBR), butyl rubber (IIR) and EPDM rubber. Vulcanization, in common with the curing of other thermosetting polymers, is generally irreversible. However, there has been significant effort to try and develop 'de-vulcanisation' processes in order to improve the recycling of rubber wastes. The chemistry of vulcanisation is complex, and there has long"
"that after the mineral had crystallized it was partly again dissolved or corroded at some period before the matrix solidified. Corroded phenocrysts of biotite and hornblende are very common in some lavas; they are surrounded by black rims of magnetite mixed with pale green augite. The hornblende or biotite substance has proved unstable at a certain stage of consolidation, and has been replaced by a paramorph of augite and magnetite, which may partially or completely substitute for the original crystal but still retains its characteristic outlines. Volcanic rock Volcanic rock (often shortened to volcanics in scientific contexts) is a rock"
"stay solid. In the thermosetting process, a chemical reaction occurs that is irreversible. The vulcanization of rubber is an example of a thermosetting process: before heating with sulfur, the polyisoprene is a tacky, slightly runny material; after vulcanization, the product is rigid and non-tacky. Many plastics are completely amorphous, such as: all thermosets; polystyrene and its copolymers; and polymethyl methacrylate. However, some plastics are partially crystalline and partially amorphous in molecular structure, giving them both a melting point, the temperature at which the attractive intermolecular forces are overcome, and also one or more glass transitions, the temperatures above which the"
"differentiated planets built from similar chondritic materials. Many of the same magmatic processes that occur on Earth also occurred on Mars, and both planets are similar enough compositionally that the same names can be applied to their igneous rocks and minerals. Volcanism is a process in which magma from a planet’s interior rises through the crust and erupts on the surface. The erupted materials consist of molten rock (lava), hot fragmental debris (tephra or ash), and gases. Volcanism is a principal way that planets release their internal heat. Volcanic eruptions produce distinctive landforms, rock types, and terrains that provide a"
"melting point, such as iron and nickel. They are unlikely to possess a regolith because such fragmented material heats and cools more rapidly, and is affected more strongly by the Yarkovsky effect, than solid rock. Vulcanoids are probably similar to Mercury in colour and albedo, and may contain material left over from the earliest stages of the Solar System's formation. There is evidence that Mercury was struck by a large object relatively late in its development, a collision which stripped away much of Mercury's crust and mantle, and explaining the thinness of Mercury's mantle compared to the mantles of the"
"Volcanism Volcanism is the phenomenon of eruption of molten rock (magma) onto the surface of the Earth or a solid-surface planet or moon, where lava, pyroclastics and volcanic gases erupt through a break in the surface called a vent. It includes all phenomena resulting from and causing magma within the crust or mantle of the body, to rise through the crust and form volcanic rocks on the surface. Magma from the mantle or lower crust rises through its crust towards the surface. If magma reaches the surface, its behavior depends on the viscosity of the molten constituent rock. Viscous (thick)"
"Plutonism Plutonism (or volcanism) is the geologic theory that the igneous rocks forming the Earth originated from intrusive magmatic activity, with a continuing gradual process of weathering and erosion wearing away rocks, which were then deposited on the sea bed, re-formed into layers of sedimentary rock by heat and pressure, and raised again. It proposes that basalt is solidified molten magma. The name ""plutonism"" references Pluto, the classical ruler of the underworld, while ""volcanism"" echoes the name of Vulcan, the ancient Roman god of fire and volcanoes. The ""Oxford English Dictionary"" traces use of the word ""plutonists"" to 1799, and"
"flaking on one side only). Cryptocrystalline or amorphous stone such as chert, flint, obsidian, and chalcedony, as well as other fine-grained stone material, such as rhyolite, felsite, and quartzite, were used as a source material for producing stone tools. As these materials lack natural planes of separation, conchoidal fractures occur when they are struck with sufficient force; for these stones this process is called knapping. The propagation of force through the material takes the form of a Hertzian cone that originates from the point of impact and results in the separation of material from the objective piece, usually in the"
"may be closely controlled. Any fusible material can be atomized. Several techniques have been developed which permit large production rates of powdered particles, often with considerable control over the size ranges of the final grain population. Powders may be prepared by crushing, grinding, chemical reactions, or electrolytic deposition. Powders of the elements titanium, vanadium, thorium, niobium, tantalum, calcium, and uranium have been produced by high-temperature reduction of the corresponding nitrides and carbides. Iron, nickel, uranium, and beryllium submicrometre powders are obtained by reducing metallic oxalates and formates. Exceedingly fine particles also have been prepared by directing a stream of molten"
"volcanic rock they are selling. The sub-family of rocks that form from volcanic lava are called igneous volcanic rocks (to differentiate them from igneous rocks that form from magma below the surface, called igneous plutonic rocks). The lavas of different volcanoes, when cooled and hardened, differ much in their appearance and composition. If a rhyolite lava-stream cools quickly, it can quickly freeze into a black glassy substance called obsidian. When filled with bubbles of gas, the same lava may form the spongy appearing pumice. Allowed to cool slowly, it forms a light-colored, uniformly solid rock called rhyolite. The lavas, having"
"a small gap between moving machine parts was to use leather soaked in oil. This practice was acceptable only at moderate pressures, but above a certain point, machine designers were forced to compromise between the extra friction generated by tighter packing and greater leakage of steam. Vulcanized rubber solved this problem. It could be formed to precise shapes and dimensions, it accepted moderate to large deformations under load and recovered quickly to its original dimensions once the load is removed. These exceptional qualities, combined with good durability and lack of stickiness, were critical for an effective sealing material. Further experiments"
"performing a post-extrusion curing. The chemical process of vulcanization is a type of cross-linking that changes rubber to the hard, durable material associated with car and bike tires. This process is often called sulfur curing; the term vulcanization comes from Vulcan, the Roman god of fire. This is, however, a slower process. A typical car tire is cured for 15 minutes at 150 °C. However, the time can be reduced by the addition of accelerators such as 2-benzothiazolethiol or tetramethylthiuram disulfide. Both of these contain a sulfur atom in the molecule that initiates the reaction of the sulfur chains with"
"Volcanic rock Volcanic rock (often shortened to volcanics in scientific contexts) is a rock formed from magma erupted from a volcano. In other words, it differs from other igneous rock by being of volcanic origin. Like all rock types, the concept of volcanic rock is artificial, and in nature volcanic rocks grade into hypabyssal and metamorphic rocks and constitute an important element of some sediments and sedimentary rocks. For these reasons, in geology, volcanics and shallow hypabyssal rocks are not always treated as distinct. In the context of Precambrian shield geology, the term ""volcanic"" is often applied to what are"
"barrier to the re-release of CO into the atmosphere. Basalt Basalt (, ) is a mafic extrusive igneous rock formed from the rapid cooling of magnesium-rich and iron-rich lava exposed at or very near the surface of a terrestrial planet or a moon. More than 90% of all volcanic rock on Earth is basalt. Basalt lava has a low viscosity, due to its low silica content, resulting in rapid lava flows that can spread over great areas before cooling and solidification. Flood basalt describes the formation in a series of lava basalt flows. By definition, basalt is an aphanitic (fine-grained)"
"industry has started a research project SafeRubber to develop a safer alternative to the use of ETU. Room-temperature vulcanizing (RTV) silicone is constructed of reactive oil-based polymers combined with strengthening mineral fillers. There are two types of room-temperature vulcanizing silicone: Vulcanization Vulcanization (British: vulcanisation) is a chemical process used to harden rubber. Vulcanization traditionally referred to the treatment of natural rubber with sulfur and this remains the most common example, however the term has also grown to include the hardening of other (synthetic) rubbers via various means. Examples include silicone rubber via room temperature vulcanizing and chloroprene rubber (neoprene) using"
"synthetic polyolefins. Accelerated vulcanization is carried out using various compounds that modify the kinetics of crosslinking, this mixture is often referred to as a cure package. The main polymers subjected to sulfur vulcanization are polyisoprene (natural rubber) and styrene-butadiene rubber (SBR), which are used for most street-vehicle tires. The cure package is adjusted specifically for the substrate and the application. The reactive sites—cure sites—are allylic hydrogen atoms. These C-H bonds are adjacent to carbon-carbon double bonds. During vulcanization, some of these C-H bonds are replaced by chains of sulfur atoms that link with a cure site of another polymer chain."
"Pumice Pumice (), called pumicite in its powdered or dust form, is a volcanic rock that consists of highly vesicular rough textured volcanic glass, which may or may not contain crystals. It is typically light colored. Scoria is another vesicular volcanic rock that differs from pumice in having larger vesicles, thicker vesicle walls and being dark colored and denser. Pumice is created when super-heated, highly pressurized rock is violently ejected from a volcano. The unusual foamy configuration of pumice happens because of simultaneous rapid cooling and rapid depressurization. The depressurization creates bubbles by lowering the solubility of gases (including water"
"has thermally contracted to become dense, and it sinks under its own weight in the process of subduction usually at an ocean trench. This subducted material sinks through the Earth's interior. Some subducted material appears to reach the lower mantle, while in other regions, this material is impeded from sinking further, possibly due to a phase transition from spinel to silicate perovskite and magnesiowustite, an endothermic reaction. The subducted oceanic crust triggers volcanism, although the basic mechanisms are varied. Volcanism may occur due to processes that add buoyancy to partially melted mantle causing an upward flow due to a decrease"
"decreases when it flows to the surface. These violent explosions produce solid chunks of material that can then fly from the volcano. Chunks smaller than 2 mm in diameter (sand-sized or smaller) are called volcanic ash. Among the loose beds of ash that cover the slopes of many volcanoes, three classes of materials are represented. In addition to true ashes of the kind described above, lumps of the old lavas and tuffs form the walls of the crater, which have been torn away by the violent outbursts of steam, and pieces of sedimentary rocks from the deeper parts of the"
"the mining of pumice in environmentally sensitive areas has been under more scrutiny after such an operation was stopped in the U.S. state of Oregon, at Rock Mesa in the southern part of the Three Sisters Wilderness. Pumice Pumice (), called pumicite in its powdered or dust form, is a volcanic rock that consists of highly vesicular rough textured volcanic glass, which may or may not contain crystals. It is typically light colored. Scoria is another vesicular volcanic rock that differs from pumice in having larger vesicles, thicker vesicle walls and being dark colored and denser. Pumice is created when"
"Pyroclastic rock Pyroclastic rocks or pyroclastics (derived from the , meaning fire; and , meaning broken) are clastic rocks composed solely or primarily of volcanic materials. Where the volcanic material has been transported and reworked through mechanical action, such as by wind or water, these rocks are termed volcaniclastic. Commonly associated with unsieved volcanic activity—such as Plinian or krakatoan eruption styles, or phreatomagmatic eruptions—pyroclastic deposits are commonly formed from airborne ash, lapilli and bombs or blocks ejected from the volcano itself, mixed in with shattered country rock. Pyroclastic rocks may be a range of clast sizes, from the largest agglomerates,"
"a volatile and incompatible-element enriched rich partial melt of granitic composition. Such granites derived from sedimentary rock protoliths would be termed ""S-type granite"", are typically potassic, sometimes containing leucite, and would be termed adamellite, granite and syenite. Volcanic equivalents would be rhyolite and rhyodacite. Migmatised igneous or lower-crustal rocks which melt do so to form a similar granitic ""I-type granite"" melt, but with distinct geochemical signatures and typically plagioclase dominant mineralogy forming monzonite, tonalite and granodiorite compositions. Volcanic equivalents would be dacite, trachyte and trachydacite. It is difficult to melt mafic metamorphic rocks except in the lower mantle, so it"
"Obsidian Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock. Obsidian is produced when felsic lava extruded from a volcano cools rapidly with minimal crystal growth. It is commonly found within the margins of rhyolitic lava flows known as obsidian flows, where the chemical composition (high silica content) induces a high degree of viscosity and polymerization of the lava. The inhibition of atomic diffusion through this highly viscous and polymerized lava explains the lack of crystal growth. Obsidian is hard and brittle and therefore fractures with very sharp edges. In the past it was used to"
"bark. It is said to be melted 2 meters deep into the concrete. The material is dangerously radioactive and hard and strong, and using remote controlled systems was not possible due to high radiation interfering with electronics. The Chernobyl melt was a silicate melt which contained inclusions of Zr/U phases, molten steel and high levels of uranium zirconium silicate (""chernobylite"", a black and yellow technogenic mineral). The lava flow consists of more than one type of material—a brown lava and a porous ceramic material have been found. The uranium to zirconium ratio in different parts of the solid differs a"
"volcanism consists primarily of adakites (partial melts from the subducted slab) whereas the older volcanism is normal calc-alkaline lavas. In 2006, an earthquake swarm was registered in the Volcán Barú area. This was not the first one; researchers cite at least three other seismic events of the same nature recorded in the recent past (1930, 1965, 1985). In 2007, the U.S. Geological Survey (USGS), in cooperation with Panama's Science, Technology and Innovation Secretariat (SENACYT) and the U.S. Agency for International Development (USAID), published a study on different aspects of Volcán Barú. The 33-page report outlined potential hazard areas, rock composition,"
"rock are not distinguishable to the naked eye. Examples of aphanitic igneous rock include basalt, andesite and rhyolite. ""Glassy"" or ""vitreous"" textures occur during some volcanic eruptions when the lava is quenched so rapidly that crystallization cannot occur. The result is a natural amorphous glass with few or no crystals. Examples include obsidian and pumice. ""Pegmatitic"" texture occurs during magma cooling when some minerals may grow so large that they become massive (the size ranges from a few centimetres to several metres). This is typical of pegmatites. ""Phaneritic"" (""phaner"" = visible) textures are typical of intrusive igneous rocks, these rocks"