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Breathability
Breathability is the ability of a fabric to allow moisture vapor to be transmitted through the material. Mechanism Air permeability is the ability of a fabric to allow air to pass through it. While air permeable fabrics tend to have relatively high moisture vapor transmission, it is not necessary to be air permeable to be breathable. Moisture Vapor Transfer (MVT) in waterproof fabrics occurs by two processes: * Physical: Hydrophobic (water fearing) are water proof, yet steam permeable -microporous coatings or laminations have pores that are so small that liquid water cannot go through. However, vapor water molecules are many times smaller than the liquid state and can pass through these “micro pores”. * Chemical: Hydrophilic (water loving) / non-porous lamination or coating move moisture by chemical diffusion. The water molecule is positively charged and the hydrophilic PU is negatively charged, attracting the water through the intermolecular gaps of the PU. Because the ionic b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vapor
In physics, a vapor (American English) or vapour (British English and Canadian English; American and British English spelling differences#-our, -or, see spelling differences) is a substance in the gas phase at a temperature lower than its critical temperature,R. H. Petrucci, W. S. Harwood, and F. G. Herring, ''General Chemistry'', Prentice-Hall, 8th ed. 2002, p. 483–86. which means that the vapor can be condensation, condensed to a liquid by increasing the pressure on it without reducing the temperature. A vapor is different from an aerosol. An aerosol is a suspension of tiny particles of liquid, solid, or both within a gas. For example, water has a critical temperature of , which is the highest temperature at which liquid water can exist. In the Earth's atmosphere, atmosphere at ordinary temperatures gaseous water (known as water vapor) will condense into a liquid if its partial pressure is increased sufficiently. A vapor may co-exist with a liquid (or a solid). When this is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air Permeability
Textile fibers, threads, yarns and fabrics are measured in a multiplicity of units. * A fiber, a single filament of natural material, such as cotton, linen or wool, or artificial material such as nylon, polyester, metal or mineral fiber, or man-made cellulosic fibre like viscose, Modal, Lyocell or other rayon fiber is measured in terms of linear mass density, the weight of a given length of fiber. Various units are used to refer to the measurement of a fiber, such as: the denier and tex (linear mass density of fibers), super S (fineness of wool fiber), worsted count, woolen count, linen count (wet spun) (or Number English (Ne)), cotton count (or Number English (Ne)), Number metric (Nm) and yield (the reciprocal of denier and tex). * A yarn, a spun agglomeration of fibers used for knitting, weaving or sewing, is measured in terms of cotton count and yarn density. * Thread, usually consisting of multiple yarns plied together producing a long, thin strand used in sewing or weavi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrophilic
A hydrophile is a molecule or other molecular entity that is attracted to water molecules and tends to be dissolved by water.Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon'' Oxford: Clarendon Press. In contrast, hydrophobes are not attracted to water and may seem to be repelled by it. Hygroscopics ''are'' attracted to water, but are not dissolved by water. Molecules A hydrophilic molecule or portion of a molecule is one whose interactions with water and other polar substances are more thermodynamically favorable than their interactions with oil or other hydrophobic solvents. They are typically charge-polarized and capable of hydrogen bonding. This makes these molecules soluble not only in water but also in other polar solvents. Hydrophilic molecules (and portions of molecules) can be contrasted with hydrophobic molecules (and portions of molecules). In some cases, both hydrophilic and hydrophobic properties occur in a single molecule. An example of these amphiph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Second Law Of Thermodynamics
The second law of thermodynamics is a physical law based on universal experience concerning heat and Energy transformation, energy interconversions. One simple statement of the law is that heat always moves from hotter objects to colder objects (or "downhill"), unless energy in some form is supplied to reverse the direction of heat flow. Another definition is: "Not all heat energy can be converted into Work (thermodynamics), work in a cyclic process."Young, H. D; Freedman, R. A. (2004). ''University Physics'', 11th edition. Pearson. p. 764. The second law of thermodynamics in other versions establishes the concept of entropy as a physical property of a thermodynamic system. It can be used to predict whether processes are forbidden despite obeying the requirement of conservation of energy as expressed in the first law of thermodynamics and provides necessary criteria for spontaneous processes. The second law may be formulated by the observation that the entropy of isolated systems ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Differential Pressure
Pressure measurement is the measurement of an applied force by a fluid ( liquid or gas) on a surface. Pressure is typically measured in units of force per unit of surface area. Many techniques have been developed for the measurement of pressure and vacuum. Instruments used to measure and display pressure mechanically are called pressure gauges, vacuum gauges or compound gauges (vacuum & pressure). The widely used Bourdon gauge is a mechanical device, which both measures and indicates and is probably the best known type of gauge. A vacuum gauge is used to measure pressures lower than the ambient atmospheric pressure, which is set as the zero point, in negative values (for instance, −1 bar or −760 mmHg equals total vacuum). Most gauges measure pressure relative to atmospheric pressure as the zero point, so this form of reading is simply referred to as "gauge pressure". However, anything greater than total vacuum is technically a form of pressure. For very low pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hohenstein Test
Hohenstein may refer to: People * Adolfo Hohenstein (1854–1928), German painter, advertiser, illustrator * Rory Hohenstein, American ballet dancer * Wes Hohenstein, American television meteorologist Places * Hohenstein (Reutlingen), a municipality in Baden-Württemberg, Germany * Hohenstein (Strausberg), a civil parish of Strausberg, Brandenburg, Germany * Hohenstein, Hesse, Germany * Hohenstein, Thuringia, Germany * Hohenstein-Ernstthal, Saxony, Germany * Olsztynek, Poland, called Hohenstein in German * Sayn-Wittgenstein-Hohenstein Sayn-Wittgenstein-Hohenstein was a county and later principality between Hesse-Darmstadt and Westphalia. History The county with imperial immediacy was formed by the 1657 partition of Sayn-Wittgenstein-Wittgenstein and raised from a county to ..., a county of the Holy Roman Empire (1657–1806) Other uses * Hohenstein Institute {{disambiguation, geo, surname ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sintered
Clinker nodules produced by sintering Sintering or frittage is the process of compacting and forming a solid mass of material by pressure or heat without melting it to the point of liquefaction. Sintering happens as part of a manufacturing process used with metals, ceramics, plastics, and other materials. The atoms in the materials diffuse across the boundaries of the particles, fusing the particles together and creating one solid piece. Because the sintering temperature does not have to reach the melting point of the material, sintering is often chosen as the shaping process for materials with extremely high melting points such as tungsten and molybdenum. The study of sintering in metallurgical powder-related processes is known as powder metallurgy. An example of sintering can be observed when ice cubes in a glass of water adhere to each other, which is driven by the temperature difference between the water and the ice. Examples of pressure-driven sintering are the compact ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gore-Tex
Gore-Tex is a waterproof, breathable fabric membrane and registered trademark of W. L. Gore & Associates. Invented in 1969, Gore-Tex can repel liquid water while allowing water vapor to pass through and is designed to be a lightweight, waterproof fabric for all-weather use. It is composed of stretched polytetrafluoroethylene (PTFE), which is more commonly known by the generic trademark Teflon. The material is formally known as the generic term expanded PTFE (ePTFE). History Gore-Tex was co-invented by Wilbert L. Gore and Gore's son, Robert W. Gore. In 1969, Bob Gore stretched heated rods of polytetrafluoroethylene (PTFE) and created expanded polytetrafluoroethylene (ePTFE). His discovery of the right conditions for stretching PTFE was a happy accident, born partly of frustration. Instead of slowly stretching the heated material, he applied a sudden, accelerating yank. The solid PTFE unexpectedly stretched about 800%, forming a microporous structure that was about 70% air. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Windstopper
Windstopper is a windproof breathable fabric laminate made by W. L. Gore & Associates. One of its most common applications is a lamination with polar fleece, to compensate for fleece's lack of wind resistance. Unlike Gore's well-known Gore-Tex laminate, Windstopper is not waterproof. Use Many Windstopper garments are marketed as "softshells" suited to high-output aerobic activities such as running, cycling or cross-country skiing. Because they are not waterproof, they are more breathable than traditional Gore-Tex "hardshell" clothing. However, because they are based on a solid laminate layer, they remain inherently less breathable than other wind-resistant "softshell" fabrics made by Polartec or Schoeller, which rely on built-in properties of the fabric and weave rather than laminates. Like most softshell fabrics, Windstopper products are typically coated with DWR (Durable Water Repellent), which provides them with a modest degree of water resistance. They will wet through i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breathing
Breathing (or ventilation) is the process of moving air into and from the lungs to facilitate gas exchange with the internal environment, mostly to flush out carbon dioxide and bring in oxygen. All aerobic creatures need oxygen for cellular respiration, which extracts energy from the reaction of oxygen with molecules derived from food and produces carbon dioxide as a waste product. Breathing, or "external respiration", brings air into the lungs where gas exchange takes place in the alveoli through diffusion. The body's circulatory system transports these gases to and from the cells, where "cellular respiration" takes place. The breathing of all vertebrates with lungs consists of repetitive cycles of inhalation and exhalation through a highly branched system of tubes or airways which lead from the nose to the alveoli. The number of respiratory cycles per minute is the breathing or respiratory rate, and is one of the four primary vital signs of life. Under normal conditions t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
