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Silicone Oil
A silicone oil is any liquid polymerized siloxane with organic side chains. The most important member is polydimethylsiloxane. These polymers are of commercial interest because of their relatively high thermal stability and their lubricating properties. Structure Like all siloxanes (e.g., hexamethyldisiloxane), the polymer backbone consists of alternating silicon and oxygen atoms (...Si−O−Si−O−Si...). Many groups can be attached to the tetravalent silicon centres, but the dominant substituent is methyl or sometimes phenyl. Many silicone liquids are linear polymers end-capped with trimethylsilyl groups. Other silicone liquids are cyclosiloxanes. Applications Silicone oils are primarily used as lubricants, thermic fluid oils or hydraulic fluids. They are excellent electrical insulators and, unlike their carbon analogues, are non- flammable. Their temperature stability and good heat-transfer characteristics make them widely used in laboratories for heating baths ("oil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siloxane
In organosilicon chemistry, a siloxane is an organic compound containing a functional group of two silicon atoms bound to an oxygen atom: . The parent siloxanes include the oligomeric and polymeric hydrides with the formulae and . Siloxanes also include branched compounds, the defining feature of which is that each pair of silicon centres is separated by one oxygen atom. The siloxane functional group forms the backbone of silicones , the premier example of which is polydimethylsiloxane (PDMS). The functional group (where the three Rs may be different) is called siloxy. Siloxanes are manmade and have many commercial and industrial applications because of the compounds’ hydrophobicity, low thermal conductivity, and high flexibility. Structure Siloxanes generally adopt structures expected for linked tetrahedral ("''sp''3-like") centers. The Si−O bond length is 1.64 Å (vs Si–C distance of 1.92 Å) and the Si-O-Si angle is rather open at 142.5°. By ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dashpot
A dashpot, also known as a damper, is a mechanical device that resists motion via viscous damping. The resulting force is proportional to the velocity, but acts in the opposite direction, slowing the motion and absorbing energy. It is commonly used in conjunction with a Spring (device), spring. Types The two most common types of dashpots are linear and rotary. Linear dashpot Linear dashpots — or linear dampers — are used to exert a force opposite to a translation movement. They are generally specified by stroke (amount of linear displacement) and damping coefficient (force per velocity). Rotary dashpot Similarly, rotary dashpots will tend to oppose any torque applied to them, in an amount proportional to their rotational speed. Their damping coefficients will usually be specified by torque per angular velocity. One can distinguish two kinds of viscous rotary dashpots: * Vane dashpots which have a limited angular range but provide a significant damping torque. The damp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deep Frying
Deep frying (also referred to as deep fat frying) is a cooking method in which food is submerged in hot fat, traditionally lard but today most commonly Cooking oil, oil, as opposed to the shallow frying used in conventional frying done in a frying pan. Normally, a deep fryer or chip pan is used for this; industrially, a pressure fryer or vacuum fryer may be used. Deep frying may also be performed using oil that is heated in a pot. Deep frying is classified as a hot-fat cooking method. Typically, deep frying foods cook quickly since oil has a high rate of heat conduction and all sides of the food are cooked simultaneously. The term "deep frying" and many modern deep-fried foods were not invented until the 19th century, but the practice has been around for millennia. Early records and cookbooks suggest that the practice began in certain European countries before other countries adopted the practice. Deep frying is popular worldwide, with deep-fried foods accounting for a large por ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cooking Oils
Cooking oil (also known as edible oil) is a plant or animal liquid fat used in frying, baking, and other types of cooking. Oil allows higher cooking temperatures than water, making cooking faster and more flavorful, while likewise distributing heat, reducing burning and uneven cooking. It sometimes imparts its own flavor. Cooking oil is also used in food preparation and flavoring not involving heat, such as salad dressings and bread dips. Cooking oil is typically a liquid at room temperature, although some oils that contain saturated fat, such as coconut oil, palm oil and palm kernel oil are solid. There are a wide variety of cooking oils from plant sources such as olive oil, palm oil, soybean oil, canola oil (rapeseed oil), corn oil, peanut oil, sesame oil, sunflower oil and other vegetable oils, as well as animal-based oils like butter and lard. Oil can be flavored with aromatic foodstuffs such as herbs, chilies or garlic. Cooking spray is an aerosol of cooking oil. Health ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foam
Foams are two-phase materials science, material systems where a gas is dispersed in a second, non-gaseous material, specifically, in which gas cells are enclosed by a distinct liquid or solid material. Note, this source focuses only on liquid foams. Note, this source also focuses on liquid foams. Foam "may contain more or less liquid [or solid] according to circumstances", although in the case of gas-liquid foams, the gas occupies most of the volume. In most foams, the volume of gas is large, with thin films of liquid or solid separating the regions of gas. Etymology The word derives from the Old High German, medieval German and otherwise obsolete ''veim'', in reference to the "frothy head forming in the glass once the beer has been freshly poured" (cf. ''ausgefeimt''). Structure A foam is, in many cases, a multi-scale system. One scale is the bubble: materials science, material foams are typically randomness, disordered and have a variety of bubble sizes. At larger siz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Industrial Fermentation
Industrial fermentation is the intentional use of fermentation in manufacturing processes. In addition to the mass production of fermented foods and drinks, industrial fermentation has widespread applications in chemical industry. Commodity chemicals, such as acetic acid, citric acid, and ethanol are made by fermentation. Moreover, nearly all commercially produced industrial enzymes, such as lipase, invertase and rennet, are made by fermentation with genetically modified microbes. In some cases, production of biomass itself is the objective, as is the case for single-cell proteins, baker's yeast, and starter cultures for lactic acid bacteria used in cheesemaking. In general, fermentations can be divided into four types: * Production of biomass (viable cellular material) * Production of extracellular metabolites (chemical compounds) * Production of intracellular components (enzymes and other proteins) * Transformation of substrate (in which the transformed substrate i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Distillation
Distillation, also classical distillation, is the process of separating the component substances of a liquid mixture of two or more chemically discrete substances; the separation process is realized by way of the selective boiling of the mixture and the condensation of the vapors in a still. Distillation can operate over a wide range of pressures from 0.14 bar (e.g., ethylbenzene/ styrene) to nearly 21 bar (e.g., propylene/propane) and is capable of separating feeds with high volumetric flowrates and various components that cover a range of relative volatilities from only 1.17 ( o-xylene/ m-xylene) to 81.2 (water/ ethylene glycol). Distillation provides a convenient and time-tested solution to separate a diversity of chemicals in a continuous manner with high purity. However, distillation has an enormous environmental footprint, resulting in the consumption of approximately 25% of all industrial energy use. The key issue is that distillation operates based on phase changes, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Tension
Surface tension is the tendency of liquid surfaces at rest to shrink into the minimum surface area possible. Surface tension (physics), tension is what allows objects with a higher density than water such as razor blades and insects (e.g. Gerridae, water striders) to float on a water surface without becoming even partly submerged. At liquid–air interfaces, surface tension results from the greater attraction of liquid molecules to each other (due to Cohesion (chemistry), cohesion) than to the molecules in the air (due to adhesion). There are two primary mechanisms in play. One is an inward force on the surface molecules causing the liquid to contract. Second is a tangential force parallel to the surface of the liquid. This ''tangential'' force is generally referred to as the surface tension. The net effect is the liquid behaves as if its surface were covered with a stretched elastic membrane. But this analogy must not be taken too far as the tension in an elastic membrane i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simethicone
Simeticone (International Nonproprietary Name, INN), also known as simethicone (United States Adopted Name, USAN), is an anti-foaming agent used to reduce bloating, discomfort or pain caused by excessive gas. Medical uses Simeticone is used to relieve the symptoms of excessive gas in the gastrointestinal tract, namely bloating, burping, and flatulence. While there is a lack of conclusive evidence that simeticone is effective for this use, studies have shown that it can relieve symptoms of functional dyspepsia and bloating, functional bloating. It has not been fully established that simeticone is useful to treat Baby colic, colic in babies, and it is not recommended for this purpose. A study in the United Kingdom reported that according to parental perception simeticone helped infant colic in some cases. Simeticone can also be used for suspected postoperative abdominal discomfort in infants. Side effects Simeticone does not have any serious side effects. Two uncommon side ef ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volatility (chemistry)
In chemistry, volatility is a material quality which describes how readily a substance vaporizes. At a given temperature and pressure, a substance with high volatility is more likely to exist as a vapour, while a substance with low volatility is more likely to be a liquid or solid. Volatility can also describe the tendency of a vapor to condense into a liquid or solid; less volatile substances will more readily condense from a vapor than highly volatile ones. Differences in volatility can be observed by comparing how fast substances within a group evaporate (or sublimate in the case of solids) when exposed to the atmosphere. A highly volatile substance such as rubbing alcohol (isopropyl alcohol) will quickly evaporate, while a substance with low volatility such as vegetable oil will remain condensed. In general, solids are much less volatile than liquids, but there are some exceptions. Solids that sublimate (change directly from solid to vapor) such as dry ice (solid carbon di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zvezda Module
''Zvezda'', also known as the ''Zvezda'' Service Module, is a module of the International Space Station (ISS). It was the third module launched to the station, and provided all of the station's life support systems, some of which are supplemented in the US Orbital Segment (USOS), as well as living quarters for two crew members. It is the structural and functional center of the Russian Orbital Segment (ROS), which is the Russian part of the ISS. Crew assemble here to deal with emergencies on the station. The module was manufactured in the USSR by Energia, with major sub-contracting work by GKNPTs Khrunichev. ''Zvezda'' was launched on a Proton launch vehicle on 12 July 2000, and docked with the '' Zarya'' module on 26 July 2000 at 01:45 UTC. It is a descendant of the ''Salyut'' programme's. Origins The basic structural frame of ''Zvezda'', known as "DOS-8", was initially built in the mid-1980s to be the core of the '' Mir-2'' space station. This means that ''Zvezda'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
