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Specific Energy
Specific energy or massic energy is energy per unit mass. It is also sometimes called gravimetric energy density, which is not to be confused with energy density, which is defined as energy per unit volume. It is used to quantify, for example, stored heat and other thermodynamic properties of substances such as specific internal energy, specific enthalpy, specific Gibbs free energy, and specific Helmholtz free energy. It may also be used for the kinetic energy or potential energy of a body. Specific energy is an intensive property, whereas energy and mass are extensive properties. The SI unit for specific energy is the joule per kilogram (J/kg). Other units still in use worldwide in some contexts are the kilocalorie per gram (Cal/g or kcal/g), mostly in food-related topics, and watt-hours per kilogram (W⋅h/kg) in the field of batteries. In some countries the Imperial unit BTU per pound (Btu/lb) is used in some engineering and applied technical fields. Kenneth E. Hese ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Joule
The joule ( , or ; symbol: J) is the unit of energy in the International System of Units (SI). In terms of SI base units, one joule corresponds to one kilogram- metre squared per second squared One joule is equal to the amount of work done when a force of one newton displaces a body through a distance of one metre in the direction of that force. It is also the energy dissipated as heat when an electric current of one ampere passes through a resistance of one ohm for one second. It is named after the English physicist James Prescott Joule (1818–1889). Definition According to the International Bureau of Weights and Measures the joule is defined as "the work done when the point of application of 1 MKS unit of force ewtonmoves a distance of 1 metre in the direction of the force." In terms of SI base units and in terms of SI derived units with special names, the joule is defined as One joule is also equivalent to any of the following: * The work required to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International System Of Units
The International System of Units, internationally known by the abbreviation SI (from French ), is the modern form of the metric system and the world's most widely used system of measurement. It is the only system of measurement with official status in nearly every country in the world, employed in science, technology, industry, and everyday commerce. The SI system is coordinated by the International Bureau of Weights and Measures, which is abbreviated BIPM from . The SI comprises a coherent system of units of measurement starting with seven base units, which are the second (symbol s, the unit of time), metre (m, length), kilogram (kg, mass), ampere (A, electric current), kelvin (K, thermodynamic temperature), mole (mol, amount of substance), and candela (cd, luminous intensity). The system can accommodate coherent units for an unlimited number of additional quantities. These are called coherent derived units, which can always be represented as products of powers of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steam Table
This page provides supplementary data to the article properties of water. Further comprehensive authoritative data can be found at the ''NIST Chemistry WebBook'' page on thermophysical properties of fluids. Structure and properties Thermodynamic properties Liquid physical properties Water/steam equilibrium properties Vapor pressure formula for steam in equilibrium with liquid water: : \log_ P = A - \frac, where ''P'' is equilibrium vapor pressure in k Pa, and ''T'' is temperature in kelvins. For ''T'' = 273 K to 333 K: ''A'' = 7.2326; ''B'' = 1750.286; ''C'' = 38.1. For ''T'' = 333 K to 423 K: ''A'' = 7.0917; ''B'' = 1668.21; ''C'' = 45.1. Data in the table above is given for water–steam equilibria at various temperatures over the entire temperature range at which liquid water can exist. Pressure of the equilibrium is given in the second column in k Pa. The third column is the heat content of each gram of the liquid phase relative to water at 0 °C. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SI Unit
The International System of Units, internationally known by the abbreviation SI (from French ), is the modern form of the metric system and the world's most widely used system of units of measurement, system of measurement. It is the only system of measurement with official status in nearly every country in the world, employed in science, technology, industry, and everyday commerce. The SI system is coordinated by the International Bureau of Weights and Measures, which is abbreviated BIPM from . The SI comprises a coherence (units of measurement), coherent system of unit of measurement, units of measurement starting with seven SI base unit, base units, which are the second (symbol s, the unit of time), metre (m, length), kilogram (kg, mass), ampere (A, electric current), kelvin (K, thermodynamic temperature), mole (unit), mole (mol, amount of substance), and candela (cd, luminous intensity). The system can accommodate coherent units for an unlimited number of additional quantiti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calorie
The calorie is a unit of energy that originated from the caloric theory of heat. The large calorie, food calorie, dietary calorie, kilocalorie, or kilogram calorie is defined as the amount of heat needed to raise the temperature of one liter of water by one degree Celsius (or one kelvin). The small calorie or gram calorie is defined as the amount of heat needed to cause the same increase in one milliliter of water. Thus, 1 large calorie is equal to 1,000 small calories. In nutrition and food science, the term ''calorie'' and the symbol ''cal'' may refer to the large unit or to the small unit in different regions of the world. It is generally used in publications and package labels to express the energy value of foods in per serving or per weight, recommended dietary caloric intake, metabolic rates, etc. Some authors recommend the spelling ''Calorie'' and the symbol ''Cal'' (both with a capital C) if the large calorie is meant, to avoid confusion; however, this convention ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mole (unit)
The mole (symbol mol) is a unit of measurement, the base unit in the International System of Units (SI) for ''amount of substance'', an SI base quantity proportional to the number of elementary entities of a substance. One mole is an aggregate of exactly elementary entities (approximately 602 sextillion or 602 billion times a trillion), which can be atoms, molecules, ions, ion pairs, or other particles. The number of particles in a mole is the Avogadro number (symbol ) and the numerical value of the '' Avogadro constant'' (symbol ) expressed in mol−1. The relationship between the mole, Avogadro number, and Avogadro constant can be expressed in the following equation:1\text = \frac = \frac The current SI value of the mole is based on the historical definition of the mole as the amount of substance that corresponds to the number of atoms in 12 grams of 12C, which made the molar mass of a compound in grams per mole, numerically equal to the average molecular mass or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemistry
Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies the chemical elements that make up matter and chemical compound, compounds made of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during chemical reaction, reactions with other chemical substance, substances. Chemistry also addresses the nature of chemical bonds in chemical compounds. In the scope of its subject, chemistry occupies an intermediate position between physics and biology. It is sometimes called the central science because it provides a foundation for understanding both Basic research, basic and Applied science, applied scientific disciplines at a fundamental level. For example, chemistry explains aspects of plant growth (botany), the formation of igneous rocks (geology), how atmospheric ozone is formed and how environmental pollutants are degraded (ecology), the prop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molar Energy
The joule per mole (symbol: J·mol−1 or J/mol) is the unit of energy per amount of substance in the International System of Units (SI), such that energy is measured in joules, and the amount of substance is measured in moles. It is also an SI derived unit of molar thermodynamic energy defined as the energy equal to one joule in one mole of substance. For example, the Gibbs free energy of a compound in the area of thermochemistry is often quantified in units of kilojoules per mole (symbol: kJ·mol−1 or kJ/mol), with 1 kilojoule = 1000 joules. Physical quantities measured in J·mol−1 usually describe quantities of energy transferred during phase transformations or chemical reactions. Division by the number of moles facilitates comparison between processes involving different quantities of material and between similar processes involving different types of materials. The precise meaning of such a quantity is dependent on the context (what substances are involved, circumst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centrifugal Force
Centrifugal force is a fictitious force in Newtonian mechanics (also called an "inertial" or "pseudo" force) that appears to act on all objects when viewed in a rotating frame of reference. It appears to be directed radially away from the axis of rotation of the frame. The magnitude of the centrifugal force ''F'' on an object of mass ''m'' at the perpendicular distance ''ρ'' from the axis of a rotating frame of reference with angular velocity is F = m\omega^2 \rho. This fictitious force is often applied to rotating devices, such as centrifuges, centrifugal pumps, centrifugal governors, and centrifugal clutches, and in centrifugal railways, planetary orbits and banked curves, when they are analyzed in a non–inertial reference frame such as a rotating coordinate system. The term has sometimes also been used for the '' reactive centrifugal force'', a real frame-independent Newtonian force that exists as a reaction to a centripetal force in some scenarios. History F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Specific Strength
The specific strength is a material's (or muscle's) strength (force per unit area at failure) divided by its density. It is also known as the strength-to-weight ratio or strength/weight ratio or strength-to-mass ratio. In fiber or textile applications, tenacity is the usual measure of specific strength. The SI unit for specific strength is Pa⋅ m3/ kg, or N⋅m/kg, which is dimensionally equivalent to m2/s2, though the latter form is rarely used. Specific strength has the same units as specific energy, and is related to the maximum specific energy of rotation that an object can have without flying apart due to centrifugal force. Another way to describe specific strength is breaking length, also known as self support length: the maximum length of a vertical column of the material (assuming a fixed cross-section) that could suspend its own weight when supported only at the top. For this measurement, the definition of weight is the force of gravity at the Earth's surface (stand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Engineering
Engineering is the practice of using natural science, mathematics, and the engineering design process to Problem solving#Engineering, solve problems within technology, increase efficiency and productivity, and improve Systems engineering, systems. Modern engineering comprises many subfields which include designing and improving infrastructure, machinery, vehicles, electronics, Materials engineering, materials, and energy systems. The Academic discipline, discipline of engineering encompasses a broad range of more Academic specialization, specialized fields of engineering, each with a more specific emphasis for applications of applied mathematics, mathematics and applied science, science. See glossary of engineering. The word '':wikt:engineering, engineering'' is derived from the Latin . Definition The American Engineers' Council for Professional Development (the predecessor of the Accreditation Board for Engineering and Technology aka ABET) has defined "engineering" as: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pound (mass)
The pound or pound-mass is a unit of mass used in both the British imperial and United States customary systems of measurement. Various definitions have been used; the most common today is the international avoirdupois pound, which is legally defined as exactly , and which is divided into 16 avoirdupois ounces. The international standard symbol for the avoirdupois pound is lb; an alternative symbol (when there might otherwise be a risk of confusion with the pound-force) is lbm (for most pound definitions), # ( chiefly in the U.S.), and or ̶ (specifically for the apothecaries' pound). The unit is descended from the Roman (hence the symbol ''lb'', descended from the scribal abbreviation, '). The English word ''pound'' comes from the Roman ('the weight measured in '), and is cognate with, among others, German , Dutch , and Swedish . These units are now designated as historical and are no longer in common usage, being replaced by the metric system. Usage of the un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
