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Polycarbonate POLYCARBONATES (PC) are a group of thermoplastic polymers containing carbonate groups in their chemical structures. Polycarbonates used in engineering are strong, tough materials, and some grades are optically transparent. They are easily worked, molded , and thermoformed . Because of these properties, polycarbonates find many applications. Polycarbonates do not have a unique resin identification code (RIC) and are identified as "Other", 7 on the RIC list. Products made from polycarbonate can contain the precursor monomer bisphenol A (BPA) [...More...]  "Polycarbonate" on: Wikipedia Yahoo 

Vicat Softening Point VICAT SOFTENING TEMPERATURE or VICAT HARDNESS is the determination of the softening point for materials that have no definite melting point , such as plastics . It is taken as the temperature at which the specimen is penetrated to a depth of 1 mm by a flatended needle with a 1 mm2 circular or square crosssection. For the Vicat A test, a load of 10 N is used. For the Vicat B test, the load is 50 N. Standards to determine Vicat softening point Vicat softening point include ASTM ASTM D 1525 and ISO 306, which are largely equivalent. Property information for specific grades of resin are available in the Prospector Plastic Database. Property Search lets you search for plastics by more than 400 material properties. Vicat Softening Temperature  ISO 306 The vicat softening temperature can be used to compare the heatcharacteristics of different materials. Four different methods may be used for testing [...More...]  "Vicat Softening Point" on: Wikipedia Yahoo 

Heat Deflection Temperature The HEAT DEFLECTION TEMPERATURE or HEAT DISTORTION TEMPERATURE (HDT, HDTUL, OR DTUL) is the temperature at which a polymer or plastic sample deforms under a specified load. This property of a given plastic material is applied in many aspects of product design, engineering and manufacture of products using thermoplastic components. DETERMINATIONThe heat distortion temperature is determined by the following test procedure outlined in ASTM D648. The test specimen is loaded in threepoint bending in the edgewise direction. The outer fiber stress used for testing is either 0.455 MPa or 1.82 MPa, and the temperature is increased at 2 °C/min until the specimen deflects 0.25 mm. This is similar to the test procedure defined in the ISO 75 standard. Limitations that are associated with the determination of the HDT is that the sample is not thermally isotropic and, in thick samples in particular, will contain a temperature gradient [...More...]  "Heat Deflection Temperature" on: Wikipedia Yahoo 

Newton (unit) The NEWTON (symbol: N) is the International System of Units (SI) derived unit of force . It is named after Isaac Newton Isaac Newton in recognition of his work on classical mechanics , specifically Newton\'s second law of motion . See below for the conversion factors . CONTENTS * 1 Definition * 2 Examples * 3 Commonly seen as kilonewtons * 4 Conversion factors * 5 See also * 6 Notes and references DEFINITIONOne newton is the force needed to accelerate one kilogram of mass at the rate of one metre per second squared in direction of the applied force. In 1946, Conférence Générale des Poids et Mesures (CGPM) resolution 2 standardized the unit of force in the MKS system of units to be the amount needed to accelerate 1 kilogram of mass at the rate of 1 metre per second squared . In 1948, the 9th CGPM resolution 7 adopted the name "newton" for this force [...More...]  "Newton (unit)" on: Wikipedia Yahoo 

Thermal Conductivity Thermal CONDUCTIVITY (often denoted k, λ, or κ) is the property of a material to conduct heat . It is evaluated primarily in terms of Fourier\'s Law for heat conduction . Heat transfer Heat transfer occurs at a lower rate across materials of low thermal conductivity than across materials of high thermal conductivity. Correspondingly, materials of high thermal conductivity are widely used in heat sink applications and materials of low thermal conductivity are used as thermal insulation . The thermal conductivity of a material may depend on temperature. The reciprocal of thermal conductivity is called thermal resistivity. Thermal conductivity Thermal conductivity is actually a tensor , which means it is possible to have different values in different directions. See #Thermal anisotropy below [...More...]  "Thermal Conductivity" on: Wikipedia Yahoo 

Watt The WATT (symbol: W) is a unit of power . In the International System of Units (SI) it is defined as a derived unit of 1 joule per second , and is used to quantify the rate of energy transfer . In dimensional analysis it is described by M L 2 T 3 {displaystyle {mathsf {ML}}^{2}{mathsf {T}}^{3}} . CONTENTS * 1 Examples * 2 Origin and adoption as an SI unit * 3 Multiples * 3.1 Femtowatt * 3.2 Picowatt * 3.3 Nanowatt * 3.4 Microwatt * 3.5 Milliwatt * 3.6 Kilowatt * 3.7 Megawatt * 3.8 Gigawatt * 3.9 Terawatt * 3.10 Petawatt * 4 Conventions in the electric power industry * 5 Radio Radio transmission * 6 Distinction between watts and watthours * 7 See also * 8 Notes * 9 References * 10 External links EXAMPLESWhen an object's velocity is held constant at one meter per second against a constant opposing force of one newton , the rate at which work is done is 1 watt [...More...]  "Watt" on: Wikipedia Yahoo 

Glass Transition Temperature TEMPERATURE is a physical quantity expressing the subjective perceptions of hot and cold . Temperature Temperature is measured with a thermometer , historically calibrated in various temperature scales and units of measurement . The most commonly used scales are the Celsius scale Celsius scale , denoted in °C (informally, degrees centigrade), the Fahrenheit scale Fahrenheit scale (°F), and the Kelvin scale Kelvin scale . The kelvin (K) is the unit of temperature in the International System of Units International System of Units (SI), in which temperature is one of the seven fundamental base units . The lowest theoretical temperature is absolute zero , at which the thermal motion of all fundamental particles in matter reaches a minimum. Although classically described as motionless, particles still possess a finite zeropoint energy in the quantum mechanical description [...More...]  "Glass Transition Temperature" on: Wikipedia Yahoo 

Speed Of Sound The SPEED OF SOUND is the distance travelled per unit time by a sound wave as it propagates through an elastic medium. In dry air at 0°C (32°F), the speedofsound is 742.5 mph. At 20 °C (68 °F), the speed of sound is 343 metres per second (1,125 ft/s; 1,235 km/h; 767 mph; 667 kn), or a kilometre in 2.91 s or a mile in 4.69 s. The speed of sound in an ideal gas depends only on its temperature and composition. The speed has a weak dependence on frequency and pressure in ordinary air, deviating slightly from ideal behavior. In common everyday speech, speed of sound refers to the speed of sound waves in air . However, the speed of sound varies from substance to substance: sound travels most slowly in gases ; it travels faster in liquids ; and faster still in solids . For example, (as noted above), sound travels at 343 m/s in air; it travels at 1,484 m/s in water (4.3 times as fast as in air); and at 5,120 m/s in iron [...More...]  "Speed Of Sound" on: Wikipedia Yahoo 

Milli MILLI (symbol M) is a unit prefix in the metric system denoting a factor of one thousandth (10−3). Proposed in 1793 and adopted in 1795, the prefix comes from the Latin Latin mille, meaning "one thousand" (the Latin Latin plural is milia). Since 1960, the prefix is part of the International System of Units International System of Units (SI). Example: * Snow Snow is crystalline water and is about 1 millimetre in diameter [...More...]  "Milli" on: Wikipedia Yahoo 

Gram The GRAM (alternative spelling: GRAMME; SI unit symbol: G) (Greek/Latin root grámma) is a metric system unit of mass . Originally defined as "the absolute weight of a volume of pure water equal to the cube of the hundredth part of a metre , and at the temperature of melting ice" (later at 4 °C, the temperature of maximum density of water). However, in a reversal of reference and defined units, a gram is now defined as one onethousandth of the SI base unit, the kilogram , or 1×10−3 kg, which itself is now defined, not in terms of grams, but as being equal to the mass of a physical prototype of a specific alloy kept locked up and preserved by the International Bureau of Weights and Measures [...More...]  "Gram" on: Wikipedia Yahoo 

Rotation A ROTATION is a circular movement of an object around a center (or point) of rotation. A threedimensional object can always be rotates around an infinite number of imaginary lines called rotation axes /ˈæksiz/ , AKseez ). If the axis passes through the body's center of mass, the body is said to rotate upon itself, or spin. A rotation about an external point, e.g. the Earth Earth about the Sun Sun , is called a revolution or orbital revolution, typically when it is produced by gravity . The axis is called a POLE. CONTENTS * 1 Mathematics Mathematics * 2 Astronomy Astronomy * 2.1 Rotation Rotation and revolution * 2.2 Retrograde rotation * 3 Physics * 3.1 Cosmological principle * 3.2 Euler rotations * 4 Flight dynamics * 5 Amusement rides * 6 Sports * 7 Fixed axis vs [...More...]  "Rotation" on: Wikipedia Yahoo 

Coefficient Of Friction FRICTION is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. There are several types of friction: * DRY FRICTION is a force that opposes the relative lateral motion of two solid surfaces in contact. Dry friction is subdivided into static friction ("stiction ") between nonmoving surfaces, and kinetic friction between moving surfaces. With the exception of atomic or molecular friction, dry friction generally arises from the interaction of surface features, known as asperities * FLUID FRICTION describes the friction between layers of a viscous fluid that are moving relative to each other. * LUBRICATED FRICTION is a case of fluid friction where a lubricant fluid separates two solid surfaces [...More...]  "Coefficient Of Friction" on: Wikipedia Yahoo 

Kelvin The KELVIN SCALE is an absolute thermodynamic temperature scale using as its null point absolute zero , the temperature at which all thermal motion ceases in the classical description of thermodynamics . The KELVIN (symbol: K) is the base unit of temperature in the International System of Units (SI). The kelvin is defined as the fraction 1⁄273.16 of the thermodynamic temperature of the triple point of water (exactly 0.01 °C or 32.018 °F). In other words, it is defined such that the triple point of water is exactly 273.16 K. The Kelvin Kelvin scale is named after the Belfastborn, Glasgow University engineer and physicist William Thomson, 1st Baron Kelvin (1824–1907), who wrote of the need for an "absolute thermometric scale". Unlike the degree Fahrenheit Fahrenheit and degree Celsius Celsius , the kelvin is not referred to or typeset as a degree [...More...]  "Kelvin" on: Wikipedia Yahoo 

Specific Heat Capacity HEAT CAPACITY or THERMAL CAPACITY is a measurable physical quantity equal to the ratio of the heat added to (or removed from) an object to the resulting temperature change. The unit of heat capacity is joule per kelvin J K {displaystyle mathrm {tfrac {J}{K}} } , or kilogram metre squared per kelvin second squared k g m 2 K s 2 {displaystyle mathrm {tfrac {kgcdot m^{2}}{Kcdot s^{2}}} } in the International System of Units International System of Units (SI ). The dimensional form is L2MT−2Θ−1. Specific heat is the amount of heat needed to raise the temperature of one kilogram of mass by 1 kelvin. Heat Heat capacity is an extensive property of matter, meaning that it is proportional to the size of the system [...More...]  "Specific Heat Capacity" on: Wikipedia Yahoo 

Micro MICRO (symbol μ) is a unit prefix in the metric system denoting a factor of 10−6 (one millionth ). Confirmed in 1960, the prefix comes from the Greek μικρός (mikrós), meaning "small". The symbol for the prefix comes from the Greek letter Greek letter μ (mu ). It is the only SI prefix SI prefix which uses a character not from the Latin alphabet . Examples: * Typical bacteria are 1 to 10 micrometres in diameter. * Eukaryotic cells are typically 10 to 100 micrometres in diameter [...More...]  "Micro" on: Wikipedia Yahoo 

Ampere The AMPERE (symbol: A), often shortened to "amp", is the base unit of electric current in the International System of Units (SI). It is named after AndréMarie Ampère (1775–1836), French mathematician and physicist, considered the father of electrodynamics . SI defines the ampere in terms of other base units by measuring the electromagnetic force between electrical conductors carrying electric current. The earlier CGS measurement system had two different definitions of current, one essentially the same as the SI's and the other using electric charge as the base unit, with the unit of charge defined by measuring the force between two charged metal plates. The ampere was then defined as one coulomb of charge per second. In SI, the unit of charge, the coulomb, is defined as the charge carried by one ampere during one second [...More...]  "Ampere" on: Wikipedia Yahoo 