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Refrigeration And Air Condition
The term refrigeration refers to the process of removing heat from an enclosed space or substance for the purpose of lowering the temperature.International Dictionary of Refrigeration, http://dictionary.iifiir.org/search.phpASHRAE Terminology, https://www.ashrae.org/technical-resources/free-resources/ashrae-terminology Refrigeration can be considered an artificial, or human-made, cooling method. Refrigeration refers to the process by which energy, in the form of heat, is removed from a low-temperature medium and transferred to a high-temperature medium. This work of energy transfer is traditionally driven by mechanical means, but can also be driven by heat, magnetism, electricity, laser, or other means. Refrigeration has many applications, including household refrigerators, industrial freezers, cryogenics, and air conditioning. Heat pumps may use the heat output of the refrigeration process, and also may be designed to be reversible, but are otherwise similar to air conditionin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shijing
The ''Classic of Poetry'', also ''Shijing'' or ''Shih-ching'', translated variously as the ''Book of Songs'', ''Book of Odes'', or simply known as the ''Odes'' or ''Poetry'' (; ''Shī''), is the oldest existing collection of Chinese poetry, comprising 305 works dating from the 11th to 7th centuries BCE. It is one of the "Five Classics" traditionally said to have been compiled by Confucius, and has been studied and memorized by scholars in China and neighboring countries over two millennia. It is also a rich source of ''chengyu'' (four-character classical idioms) that are still a part of learned discourse and even everyday language in modern Chinese. Since the Qing dynasty, its rhyme patterns have also been analysed in the study of Old Chinese phonology. Name Early references refer to the anthology as the ''300 Poems'' (''shi''). ''The Odes'' first became known as a ''jīng'', or a "classic book", in the canonical sense, as part of the Han Dynasty official adoption of Confucia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Hadley (chemist)
John Hadley (1731 – 5 November 1764) was an English chemist and physician. Born in London to Henry Hadley, he was educated at Queens' College, Cambridge, graduating B.A. in 1753. In 1756 he was appointed the fourth Professor of Chemistry at Cambridge University, the oldest continuously occupied chair of Chemistry in the UK. During his time there he co-operated in 1758 with Benjamin Franklin on a series of experiments to investigate latent heat. They found that a mercury thermometer sprayed with ether which was then evaporated by blowing could fall to −7 degrees Celsius in a warm room. The Professorship was unpaid so Hadley studied medicine and obtained in 1758 a Physick Fellowship. He then moved to London in 1760 and got a post as Assistant Physician at St Thomas' Hospital. In 1763 he became full Physician to Charterhouse School and became a Fellow of the Royal College of Physicians. In 1758 he was elected as a Fellow of the Royal Society Fellowship of the Roya ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benjamin Franklin
Benjamin Franklin ( April 17, 1790) was an American polymath who was active as a writer, scientist, inventor, statesman, diplomat, printer, publisher, and political philosopher. Encyclopædia Britannica, Wood, 2021 Among the leading intellectuals of his time, Franklin was one of the Founding Fathers of the United States, a drafter and signer of the United States Declaration of Independence, and the first United States Postmaster General. As a scientist, he was a major figure in the American Enlightenment and the history of physics for his studies of electricity, and for charting and naming the current still known as the Gulf Stream. As an inventor, he is known for the lightning rod, bifocals, and the Franklin stove, among others. He founded many civic organizations, including the Library Company, Philadelphia's first fire department, and the University of Pennsylvania. Isaacson, 2004, p. Franklin earned the title of "The First American" for his early and indefa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heat Of Vaporization
The enthalpy of vaporization (symbol ), also known as the (latent) heat of vaporization or heat of evaporation, is the amount of energy (enthalpy) that must be added to a liquid substance to transform a quantity of that substance into a gas. The enthalpy of vaporization is a function of the pressure at which that transformation takes place. The enthalpy of vaporization is often quoted for the normal boiling temperature of the substance. Although tabulated values are usually corrected to 298 K, that correction is often smaller than the uncertainty in the measured value. The heat of vaporization is temperature-dependent, though a constant heat of vaporization can be assumed for small temperature ranges and for reduced temperature T_r \ll 1. The heat of vaporization diminishes with increasing temperature and it vanishes completely at a certain point called the critical temperature (T_r = 1). Above the critical temperature, the liquid and vapor phases are indistinguishable ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boiling Point
The boiling point of a substance is the temperature at which the vapor pressure of a liquid equals the pressure surrounding the liquid and the liquid changes into a vapor. The boiling point of a liquid varies depending upon the surrounding environmental pressure. A liquid in a partial vacuum has a lower boiling point than when that liquid is at atmospheric pressure. A liquid at low pressure has a lower boiling point than when that liquid is at atmospheric pressure. Because of this, water boils at under standard pressure at sea level, but at at altitude. For a given pressure, different liquids will boiling, boil at different temperatures. The normal boiling point (also called the atmospheric boiling point or the atmospheric pressure boiling point) of a liquid is the special case in which the vapor pressure of the liquid equals the defined atmospheric pressure at sea level, one Atmosphere (unit), atmosphere. At that temperature, the vapor pressure of the liquid becomes suffici ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diethyl Ether
Diethyl ether, or simply ether, is an organic compound in the ether class with the formula , sometimes abbreviated as (see Pseudoelement symbols). It is a colourless, highly volatile, sweet-smelling ("ethereal odour"), extremely flammable liquid. It is commonly used as a solvent in laboratories and as a starting fluid for some engines. It was formerly used as a general anesthetic, until non-flammable drugs were developed, such as halothane. It has been used as a recreational drug to cause intoxication. Production Most diethyl ether is produced as a byproduct of the vapor-phase hydration of ethylene to make ethanol. This process uses solid-supported phosphoric acid catalysts and can be adjusted to make more ether if the need arises. Vapor-phase dehydration of ethanol over some alumina catalysts can give diethyl ether yields of up to 95%. Diethyl ether can be prepared both in laboratories and on an industrial scale by the acid ether synthesis. Ethanol is mixed with a stro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vacuum
A vacuum is a space devoid of matter. The word is derived from the Latin adjective ''vacuus'' for "vacant" or "void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. Physicists often discuss ideal test results that would occur in a ''perfect'' vacuum, which they sometimes simply call "vacuum" or free space, and use the term partial vacuum to refer to an actual imperfect vacuum as one might have in a laboratory or in space. In engineering and applied physics on the other hand, vacuum refers to any space in which the pressure is considerably lower than atmospheric pressure. The Latin term ''in vacuo'' is used to describe an object that is surrounded by a vacuum. The ''quality'' of a partial vacuum refers to how closely it approaches a perfect vacuum. Other things equal, lower gas pressure means higher-quality vacuum. For example, a typical vacuum cleaner produces enough suction to reduce air pressure by around 20%. But hig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
William Cullen
William Cullen FRS FRSE FRCPE FPSG (; 15 April 17105 February 1790) was a Scottish physician, chemist and agriculturalist, and professor at the Edinburgh Medical School. Cullen was a central figure in the Scottish Enlightenment: He was David Hume's physician, and was friends with Joseph Black, Henry Home, Adam Ferguson, John Millar, and Adam Smith, among others. He was President of the Royal College of Physicians and Surgeons of Glasgow (1746–47), President of the Royal College of Physicians of Edinburgh (1773–1775) and First Physician to the King in Scotland (1773–1790). He also assisted in obtaining a royal charter for the Philosophical Society of Edinburgh, resulting in the formation of the Royal Society of Edinburgh in 1783. Cullen was a beloved teacher, and many of his students became influential figures. He kept in contact with many of his students, including Benjamin Rush, a central figure in the founding of the United States of America; John Morgan, who fou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Trade
The ice trade, also known as the frozen water trade, was a 19th-century and early-20th-century industry, centering on the east coast of the United States and Norway, involving the large-scale harvesting, transport and sale of natural ice, and later the making and sale of artificial ice, for domestic consumption and commercial purposes. Ice was cut from the surface of ponds and streams, then stored in ice houses, before being sent on by ship, barge or railroad to its final destination around the world. Networks of ice wagons were typically used to distribute the product to the final domestic and smaller commercial customers. The ice trade revolutionised the U.S. meat, vegetable and fruit industries, enabled significant growth in the fishing industry, and encouraged the introduction of a range of new drinks and foods. It only flourished in the time between the development of reliable transportation and the development of widespread mechanical refrigeration. The trade was star ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Cutting
Ice cutting is a winter task of collecting surface ice from lakes and rivers for storage in ice houses and use or sale as a cooling method. Rare today, it was common (see ice trade) before the era of widespread mechanical refrigeration and air conditioning technology. The work was done as a winter chore by many farmers and as a winter occupation by icemen. Kept insulated, the ice was preserved for cold food storage during warm weather, either on the farm or for delivery to residential and commercial customers with ice boxes. A large ice trade existed in the 19th and early 20th centuries, until mechanical refrigeration displaced it. Ice harvesting generally involved waiting until approximately a foot of ice had built up on the water surface in the winter. The ice would then be cut with either a handsaw or a powered saw blade into long continuous strips and then cut into large individual blocks for transport by wagon back to the ice house. Because snow on top of the ice slows fre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Harvesting, Massachusetts, Early 1850s
Ice is water frozen into a solid state, typically forming at or below temperatures of 0 degrees Celsius or Depending on the presence of impurities such as particles of soil or bubbles of air, it can appear transparent or a more or less opaque bluish-white color. In the Solar System, ice is abundant and occurs naturally from as close to the Sun as Mercury to as far away as the Oort cloud objects. Beyond the Solar System, it occurs as interstellar ice. It is abundant on Earth's surfaceparticularly in the polar regions and above the snow lineand, as a common form of precipitation and deposition, plays a key role in Earth's water cycle and climate. It falls as snowflakes and hail or occurs as frost, icicles or ice spikes and aggregates from snow as glaciers and ice sheets. Ice exhibits at least eighteen phases ( packing geometries), depending on temperature and pressure. When water is cooled rapidly (quenching), up to three types of amorphous ice can form depending on its his ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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