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Homologous Temperature
Homologous temperature expresses the thermodynamic temperature of a material as a fraction of the thermodynamic temperature of its melting point (i.e. using the Kelvin scale): T_H = \frac For example, the homologous temperature of lead at room temperature (25 °C) is approximately 0.50 (TH = T/Tmp = 298 K/601 K = 0.50). Significance of the homologous temperature The homologous temperature of a substance is useful for determining the rate of steady state creep (diffusion-dependent deformation). A higher homologous temperature results in an exponentially higher rate of diffusion dependent deformation. Additionally, for a given fixed homologous temperature, two materials with different melting points would have similar diffusion-dependent deformation behaviour. For example, solder (Tmp = 456 K) at 115 °C would have comparable mechanical properties to copper (Tmp = 1358 K) at 881 °C, because they would both be at 0.85Tmp despite being at diff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Thermodynamic Temperature
Thermodynamic temperature, also known as absolute temperature, is a physical quantity which measures temperature starting from absolute zero, the point at which particles have minimal thermal motion. Thermodynamic temperature is typically expressed using the Kelvin scale, where the unit of measurement is the ''kelvin'' (unit symbol: K). The Kelvin scale uses the same degree interval as the Celsius scale but is offset so that 0 K corresponds to absolute zero. For comparison, a temperature of 295 K corresponds to 21.85 °C and 71.33 °F. Another absolute scale of temperature is the Rankine scale, which is based on the Fahrenheit degree interval. Historically, thermodynamic temperature was defined by Lord Kelvin in terms of a macroscopic relation between Work (thermodynamics), thermodynamic work and Heat, heat transfer as defined in thermodynamics, but the kelvin was redefined by international agreement in 2019 in terms of phenomena that are now understood as man ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Melting Point
The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state of matter, state from solid to liquid. At the melting point the solid and liquid phase (matter), phase exist in Thermodynamic equilibrium, equilibrium. The melting point of a substance depends on pressure and is usually specified at a Standard temperature and pressure, standard pressure such as 1 Atmosphere (unit), atmosphere or 100 Pascal (unit), kPa. When considered as the temperature of the reverse change from liquid to solid, it is referred to as the freezing point or crystallization point. Because of the ability of substances to Supercooling, supercool, the freezing point can easily appear to be below its actual value. When the "characteristic freezing point" of a substance is determined, in fact, the actual methodology is almost always "the principle of observing the disappearance rather than the formation of ice, that is, the #Melting point measurements, melting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Kelvin Scale
The kelvin (symbol: K) is the base unit for temperature in the International System of Units (SI). The Kelvin scale is an absolute temperature scale that starts at the lowest possible temperature (absolute zero), taken to be 0 K. By definition, the Celsius scale (symbol °C) and the Kelvin scale have the exact same magnitude; that is, a rise of 1 K is equal to a rise of 1 °C and vice versa, and any temperature in degrees Celsius can be converted to kelvin by adding 273.15. The 19th century British scientist Lord Kelvin first developed and proposed the scale. It was often called the "absolute Celsius" scale in the early 20th century. The kelvin was formally added to the International System of Units in 1954, defining 273.16 K to be the triple point of water. The Celsius, Fahrenheit, and Rankine scales were redefined in terms of the Kelvin scale using this definition. The 2019 revision of the SI now defines the kelvin in terms of energy by setting the Bol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Creep (deformation)
In materials science, creep (sometimes called cold flow) is the tendency of a solid material to undergo slow deformation while subject to persistent mechanical stresses. It can occur as a result of long-term exposure to high levels of stress that are still below the yield strength of the material. Creep is more severe in materials that are subjected to heat for long periods and generally increases as they near their melting point. The rate of deformation is a function of the material's properties, exposure time, exposure temperature and the applied structural load. Depending on the magnitude of the applied stress and its duration, the deformation may become so large that a component can no longer perform its function – for example creep of a turbine blade could cause the blade to contact the casing, resulting in the failure of the blade. Creep is usually of concern to engineers and metallurgists when evaluating components that operate under high stresses or high temperatures ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Mechanical Strength
Mechanical may refer to: Machine * Machine (mechanical), a system of mechanisms that shape the actuator input to achieve a specific application of output forces and movement * Mechanical calculator, a device used to perform the basic operations of arithmetic * Mechanical energy, the sum of potential energy and kinetic energy * Mechanical system, a system that manages the power of forces and movements to accomplish a task * Mechanism (engineering), a portion of a mechanical device Other * Mechanical (character), one of several characters in Shakespeare's ''A Midsummer Night's Dream'' * A kind of typeface in the VOX-ATypI classification See also * Machine, especially in opposition to an electronic item * '' Mechanical Animals'', the third full-length studio release by Marilyn Manson * Manufactured or artificial, especially in opposition to a biological or natural component * Automation, using machine decisions and processing instead of human * Mechanization, using machine labor in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
