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ULT Freezer
An ultra low temperature (ULT) freezer is a refrigerator that stores contents at between . An ultra low temperature freezer is commonly referred to as a "minus 80 freezer" or a "negative 80 freezer", referring to the most common temperature standard. ULT freezers come in upright and chest freezer formats. Application In contrast to short term sample storage at by using standard refrigerators or freezers, many molecular biology or life science laboratories need long-term cryopreservation (including "cold chain" and/or " colder chain" infrastructures) for biological samples like DNA, RNA, proteins, cell extracts, or reagents. To reduce the risk of sample damage, these types of samples need extremely low temperatures of . Mammalian cells are often stored in dewars containing liquid nitrogen at . Cryogenic chest freezers can achieve temperatures down to , and may include a liquid nitrogen backup. Biological samples in ULT freezers are often stored in polymer tubes and microtube ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Revco -80 Freezer Pl
Revco Discount Drug Stores (known simply as Revco or Revco, D.S.), once based in Twinsburg, Ohio, was a major drug store chain operating through the Ohio Valley, the Mid-Atlantic states, and the Southeastern United States. The chain's stock was traded on the New York Stock Exchange under the ticker symbol RXR. Revco was sold to CVS Pharmacy for $2.8 billion in February 1997. When it was sold, the chain had over 2,500 stores. History Revco, originally known as Registered Vitamin Company, was founded in 1956 in Detroit, Michigan, by Sidney Dworkin and Bernie Shulman. Dworkin led Revco until 1986 as CEO, and then he served as chairman until 1987. Up to 1983, Revco grew tremendously; the chain had over 2,200 stores and over $2.2 billion in sales. The chain then began to stumble. In 1983, its vitamins were blamed for the deaths of a number of premature infants. In order to prevent a hostile takeover and increase short-term profitability, Dworkin then led the chain into a deal th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Southern California Edison
Southern California Edison (or SCE Corp), the largest subsidiary of Edison International, is the primary electricity supply company for much of Southern California. It provides 15 million people with electricity across a service territory of approximately 50,000 square miles. However, the Los Angeles Department of Water and Power, San Diego Gas & Electric (SDG&E), Imperial Irrigation District, and some smaller municipal utilities serve substantial portions of the southern California territory. The northern part of the state is generally served by the Pacific Gas & Electric Company of San Francisco. Other investor-owned utilities (IOUs) in California include SDG&E, PacifiCorp, Bear Valley Electric, and Liberty Utilities. Southern California Edison (SCE) still owns all of its electrical transmission facilities and equipment, but the deregulation of California's electricity market in the late 1990s forced the company to sell many of its power plants, though some were probably sold ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cooling Technology
Cooling is removal of heat, usually resulting in a lower temperature and/or phase change. Temperature lowering achieved by any other means may also be called cooling.ASHRAE Terminology, https://www.ashrae.org/technical-resources/free-resources/ashrae-terminology The transfer of thermal energy may occur via thermal radiation, heat conduction or convection. Examples can be as simple as reducing temperature of a coffee. Devices *Coolant *Cooling towers, as used in large industrial plants and power stations * Daytime passive radiative cooler *Evaporative cooler *Heat exchanger *Heat pipe *Heat sink *HVAC (Heating, Ventilation and Air Conditioning) * Intercooler *Radiative cooling in Heat shields * Radiators in automobiles *Pumpable ice technology *Thermoelectric cooling *Vortex tube The vortex tube, also known as the Ranque-Hilsch vortex tube, is a mechanical device that separates a compressed gas into hot and cold streams. The gas emerging from the hot end can reach temperature ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dry Ice
Dry ice is the solid form of carbon dioxide. It is commonly used for temporary refrigeration as CO2 does not have a liquid state at normal atmospheric pressure and sublimates directly from the solid state to the gas state. It is used primarily as a cooling agent, but is also used in fog machines at theatres for dramatic effects. Its advantages include lower temperature than that of water ice and not leaving any residue (other than incidental frost from moisture in the atmosphere). It is useful for preserving frozen foods (such as ice cream) where mechanical cooling is unavailable. Dry ice sublimates at at Earth atmospheric pressure. This extreme cold makes the solid dangerous to handle without protection from frostbite injury. While generally not very toxic, the outgassing from it can cause hypercapnia (abnormally elevated carbon dioxide levels in the blood) due to buildup in confined locations. Properties Dry ice is the solid form of carbon dioxide (CO2), a molecule co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cascade Refrigeration (two-cycle) Process Schematic Diagram
A cascade refrigeration cycle is a multi-stage thermodynamic cycle. An example two-stage process is shown at right. (Bottom on mobile) The cascade cycle is often employed for devices such as ULT freezer An ultra low temperature (ULT) freezer is a refrigerator that stores contents at between . An ultra low temperature freezer is commonly referred to as a "minus 80 freezer" or a "negative 80 freezer", referring to the most common temperature stand ...s. In a cascade refrigeration system, two or more vapor-compression cycles with different refrigerants are used. The evaporation-condensation temperatures of each cycle are sequentially lower with some overlap to cover the total temperature drop desired, with refrigerants selected to work efficiently in the temperature range they cover. The low temperature system removes heat from the space to be cooled using an evaporator, and transfers it to a heat exchanger that is cooled by the evaporation of the refrigerant of the high temperatur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propane
Propane () is a three-carbon alkane with the molecular formula . It is a gas at standard temperature and pressure, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is commonly used as a fuel in domestic and industrial applications and in low-emissions public transportation. Discovered in 1857 by the French chemist Marcellin Berthelot, it became commercially available in the US by 1911. Propane is one of a group of liquefied petroleum gases (LP gases). The others include butane, propylene, butadiene, butylene, isobutylene, and mixtures thereof. Propane has lower volumetric energy density, but higher gravimetric energy density and burns more cleanly than gasoline and coal. Propane gas has become a popular choice for barbecues and portable stoves because its low −42 °C boiling point makes it vaporise inside pressurised liquid containers (2 phases). Propane powers buses, forklifts, taxis, outboard boat motors, and ic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethane
Ethane ( , ) is an organic chemical compound with chemical formula . At standard temperature and pressure, ethane is a colorless, odorless gas. Like many hydrocarbons, ethane is isolated on an industrial scale from natural gas and as a petrochemical by-product of petroleum refining. Its chief use is as feedstock for ethylene production. Related compounds may be formed by replacing a hydrogen atom with another functional group; the ethane moiety is called an ethyl group. For example, an ethyl group linked to a hydroxyl group yields ethanol, the alcohol in beverages. History Ethane was first synthesised in 1834 by Michael Faraday, applying electrolysis of a potassium acetate solution. He mistook the hydrocarbon product of this reaction for methane and did not investigate it further. During the period 1847–1849, in an effort to vindicate the radical theory of organic chemistry, Hermann Kolbe and Edward Frankland produced ethane by the reductions of propionitrile (ethyl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or exemplified by the odors of gasoline and lighter fluid. They occur in a diverse range of molecular structures and phases: they can be gases (such as methane and propane), liquids (such as hexane and benzene), low melting solids (such as paraffin wax and naphthalene) or polymers (such as polyethylene and polystyrene). In the fossil fuel industries, ''hydrocarbon'' refers to the naturally occurring petroleum, natural gas and coal, and to their hydrocarbon derivatives and purified forms. Combustion of hydrocarbons is the main source of the world's energy. Petroleum is the dominant raw-material source for organic commodity chemicals such as solvents and polymers. Most anthropogenic (human-generated) emissions of greenhouse gases are carbon di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Refrigerants
This is a list of refrigerants, sorted by their ASHRAE-designated numbers, commonly known as R numbers. Many modern refrigerants are man-made halogenated gases, especially fluorinated gases and chlorinated gases, that are frequently referred to as Freon (a registered trademark of Chemours). The R number of a chemical refrigerant is assigned systematically according to molecular structure. First ASHRAE digit is the number of carbon atoms minus 1 (C-1); the second digit is the number of hydrogen atoms plus 1 (H+1); the third digit is the number of fluorine atoms; any remaining spaces are chlorine atoms. Eg.: R-22 aka R-022, which is chlorodifluoromethane. C=1 i.e. 1-1=0; H=1 i.e. 1+1=2; F=2 i.e 2; 1 remaining space 1=Cl. A "B" number means that one of the chlorine atoms is replaced by bromine (Br). This formula does not work with zeotropic or azeotropic blends. The table is sortable by each of the following refrigerant properties (scroll right or reduce magnification to view more ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrofluorocarbon
Hydrofluorocarbons (HFCs) are man-made organic compounds that contain fluorine and hydrogen atoms, and are the most common type of organofluorine compounds. Most are gases at room temperature and pressure. They are frequently used in air conditioning and as refrigerants; R-134a (1,1,1,2-tetrafluoroethane) is one of the most commonly used HFC refrigerants. In order to aid the recovery of the stratospheric ozone layer, HFCs were adopted to replace the more potent chlorofluorocarbons (CFCs), which were phased out from use by the Montreal Protocol, and hydrochlorofluorocarbons (HCFCs) which are presently being phased out. HFCs replaced older chlorofluorocarbons such as R-12 and hydrochlorofluorocarbons such as R-21. HFCs are also used in insulating foams, aerosol propellants, as solvents and for fire protection. They do not harm the ozone layer as much as the compounds they replace, but they do contribute to global warming, with trifluoromethane having 11,700 times the warming po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greenhouse Gas
A greenhouse gas (GHG or GhG) is a gas that Absorption (electromagnetic radiation), absorbs and Emission (electromagnetic radiation), emits radiant energy within the thermal infrared range, causing the greenhouse effect. The primary greenhouse gases in Atmosphere of Earth, Earth's atmosphere are water vapor (), carbon dioxide (), methane (), nitrous oxide (), and ozone (). Without greenhouse gases, the average temperature of Earth#Surface, Earth's surface would be about , rather than the present average of . The atmospheres of atmosphere of Venus, Venus, atmosphere of Mars, Mars and atmosphere of Titan, Titan also contain greenhouse gases. Human activities since the beginning of the Industrial Revolution (around 1750) have increased the Carbon dioxide in Earth's atmosphere, atmospheric concentration of carbon dioxide by over 50%, from 280 parts per million, ppm in 1750 to 421 ppm in 2022. The last time the atmospheric concentration of carbon dioxide was this high was over 3&nbs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cascade Refrigeration
A cascade refrigeration cycle is a multi-stage thermodynamic cycle. An example two-stage process is shown at right. (Bottom on mobile) The cascade cycle is often employed for devices such as ULT freezer An ultra low temperature (ULT) freezer is a refrigerator that stores contents at between . An ultra low temperature freezer is commonly referred to as a "minus 80 freezer" or a "negative 80 freezer", referring to the most common temperature stand ...s. In a cascade refrigeration system, two or more vapor-compression cycles with different refrigerants are used. The evaporation-condensation temperatures of each cycle are sequentially lower with some overlap to cover the total temperature drop desired, with refrigerants selected to work efficiently in the temperature range they cover. The low temperature system removes heat from the space to be cooled using an evaporator, and transfers it to a heat exchanger that is cooled by the evaporation of the refrigerant of the high temperatur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
_process_schematic_diagram.png "Click for more on -> Cascade Refrigeration (two-cycle) Process Schematic Diagram")
