Pressure-sensitive adhesive

          Pressure sensitive adhesive (PSA, self adhesive, self stick adhesive) is adhesive which forms bond when pressure is applied to marry the adhesive with the adherend. No solvent, water, or heat is needed to activate the adhesive. It is used in pressure sensitive tapes, labels, note pads, automobile trim, and a wide variety of other products.

          As the name "pressure sensitive" indicates, the degree of bond is influenced by the amount of pressure which is used to apply the adhesive to the surface.

          Surface factors such as smoothness, surface energy, removal of contaminants, etc. are also important to proper bonding.

          PSAs are usually designed to form a bond and hold properly at room temperatures. PSAs typically reduce or lose their tack at low temperatures and reduce their shear holding ability at high temperatures; special adhesives are made to function at high or low temperatures. It is important to choose an adhesive formulation which is designed for its intended use conditions.

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Refractory

          A fire brick, firebrick, or refractory brick is a block of refractory ceramic material used in lining furnaces, kilns, fireboxes, and fireplaces. A refractory brick is built primarily to withstand high temperature, but will also usually have a low thermal conductivity for greater energy efficiency. Usually dense firebricks are used in applications with extreme mechanical, chemical, or thermal stresses, such as the inside of a wood-fired kiln or a furnace, which is subject to abrasion from wood, fluxing from ash or slag, and high temperatures. In other, less harsh situations, such as in an electric or natural gas fired kiln, more porous bricks, commonly known as "kiln bricks" are a better choice. They are weaker, but they are much lighter, easier to form, and insulate far better than dense bricks. In any case, firebricks should not spall under rapid temperature change, and their strength should hold up well during rapid temperature changes.


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Refractory metals

          Refractory metals are a class of metals that are extraordinarily resistant to heat and wear. The expression is mostly used in the context of materials science, metallurgy and engineering. The definition of which elements belong to this group differs. The most common definition includes five elements: two of the fifth period (niobium andmolybdenum) and three of the sixth period (tantalum, tungsten, and rhenium). They all share some properties, including a melting point above 2000 °C and high hardness at room temperature. They are chemically inert and have a relatively high density. Their high melting points make powder metallurgy the method of choice for fabricatingcomponents from these metals. Some of their applications include tools to work metals at high temperatures, wire filaments, casting molds, and chemical reaction vessels in corrosive environments. Partly due to the high melting point, refractory metals are stable against creep deformation to very high temperatures.


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Oil shale

Oil shale

          Oil shale, also known as kerogen shale, is an organic-rich fine-grained sedimentary rock containing kerogen (a solid mixture of organic chemical compounds) from which liquid hydrocarbons called shale oil (not to be confused with tight oil—crude oil occurring naturally in shales) can be produced. Shale oil is a substitute for conventional crude oil; however, extracting shale oil from oil shale is more costly than the production of conventional crude oil both financially and in terms of its environmental impact. Deposits of oil shale occur around the world, including major deposits in the United States of America. Estimates of global deposits range from 2.8 to 3.3 trillion barrels (450×10⁹ to 520×10⁹ m³) of recoverable oil.

          Heating oil shale to a sufficiently high temperature causes the chemical process of pyrolysis to yield a vapor. Upon cooling the vapor, the liquid shale oil—an unconventional oil—is separated from combustible oil-shale gas (the term shale gas can also refer to gas occurring naturally in shales). Oil shale can also be burnt directly in furnaces as a low-grade fuel for power generation and district heating or used as a raw material in chemical and construction-materials processing.

          Oil shale gains attention as a potential abundant source of oil whenever the price of crude oil rises. At the same time, oil-shale mining and processing raise a number of environmental concerns, such as land use, waste disposal, water use, waste-water management, greenhouse-gas emissions and air pollution. Estonia and China have well-established oil shale industries, and Brazil, Germany, Russia also utilize oil shale.

          Oil shales differ from oil-bearing shales, shale deposits which contain petroleum (tight oil) that is sometimes produced from drilled wells. Examples of oil-bearing shales are the Bakken Formation, Pierre Shale, Niobrara Formation, and Eagle Ford Formation.

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Refractory anchorage

          All refractory require anchorage systems such as wire formed anchors, formed metal (for example, hexmetal) or ceramic tiles to support the refractory linings. The anchorage used for refractory on roofs and vertical walls are more critical as they must remain able to support the weight of refractory even at the elevated temperatures and operating conditions.

          The commonly used anchorages have circular or rectangular cross-section. Circular cross-section are used for low thickness refractory and they support less weight per unit area; whereas the rectangular cross-section is used for high thickness refractory and can support higher weight of refractory per unit area. The number of anchors to be used depend on the operating conditions and the refractory materials. The choice of anchors material, shape, numbers and size has significant impact on the useful life of the refractory

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Furnace

          A furnace is a device used for heating. The name derives from Latin fornax, oven.

In American English and Canadian English, the term furnace on its own is generally used to describe household heating systems based on a central furnace (known either as a boiler or a heater in British English), and sometimes as a synonym for kiln, a device used in the production of ceramics. InBritish English the term furnace is used exclusively to mean industrial furnaces which are used for many things, such as the extraction of metal from ore(smelting) or in oil refineries and other chemical plants, for example as the heat source for fractional distillation columns.

          The term furnace can also refer to a direct fired heater, used in boiler applications in chemical industries or for providing heat to chemical reactions for processes like cracking, and is part of the standard English names for many metallurgical furnaces worldwide.

The heat energy to fuel a furnace may be supplied directly by fuel combustion, by electricity such as the electric arc furnace, or through induction heatingin induction furnaces.

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Plastic explosive

          Plastic explosive is a specialised form of explosive material. It is a soft and hand moldable solid material. Plastic explosives are properly known as putty explosives within the field of explosives engineering. Common plastic explosives include Semtex and C-4. Plastic explosives are especially suited for explosive demolition as they can be easily formed into the best shapes for cutting structural members and have a high enough velocity of detonation and density for metal cutting work. They are generally not used for ordinary blasting as they tend to be significantly more expensive than other materials that perform just as well in that field. Also, when an explosive is combined with a plasticizer, its power is generally lower than when it is pure.


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