|
Normal Cubic Meter
Standard temperature and pressure (STP) are standard sets of conditions for experimental measurements to be established to allow comparisons to be made between different sets of data. The most used standards are those of the International Union of Pure and Applied Chemistry (IUPAC) and the National Institute of Standards and Technology (NIST), although these are not universally accepted standards. Other organizations have established a variety of alternative definitions for their standard reference conditions. In chemistry, IUPAC changed its definition of standard temperature and pressure in 1982: * Until 1982, STP was defined as a temperature of 273.15 K (0 °C, 32 °F) and an absolute pressure of exactly 1 atm (101.325 kPa). * Since 1982, STP has been defined as a temperature of 273.15 K (0 °C, 32 °F) and an absolute pressure of exactly 105 Pa (100 kPa, 1 bar). STP should not be confused with the standard state comm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Technical Standard
A technical standard is an established norm or requirement for a repeatable technical task which is applied to a common and repeated use of rules, conditions, guidelines or characteristics for products or related processes and production methods, and related management systems practices. A technical standard includes definition of terms; classification of components; delineation of procedures; specification of dimensions, materials, performance, designs, or operations; measurement of quality and quantity in describing materials, processes, products, systems, services, or practices; test methods and sampling procedures; or descriptions of fit and measurements of size or strength. It is usually a formal document that establishes uniform engineering or technical criteria, methods, processes, and practices. In contrast, a custom, convention, company product, corporate standard, and so forth that becomes generally accepted and dominant is often called a ''de facto'' standard. A techni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Standard Cubic Meters Per Second
Flow measurement is the quantification of bulk fluid movement. Flow can be measured in a variety of ways. The common types of flowmeters with industrial applications are listed below: * a) Obstruction type (differential pressure or variable area) * b) Inferential (turbine type) * c) Electromagnetic * d) Positive-displacement flowmeters, which accumulate a fixed volume of fluid and then count the number of times the volume is filled to measure flow. * e) Fluid dynamic (vortex shedding) * f) Anemometer * g) Ultrasonic * h) Mass flowmeter ( Coriolis force). Flow measurement methods other than positive-displacement flowmeters rely on forces produced by the flowing stream as it overcomes a known constriction, to indirectly calculate flow. Flow may be measured by measuring the velocity of fluid over a known area. For very large flows, tracer methods may be used to deduce the flow rate from the change in concentration of a dye or radioisotope. Kinds and units of measurement Both gas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IUPAC
The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering Organizations working for the advancement of the chemical sciences, especially by developing nomenclature and terminology. It is a member of the International Science Council (ISC). IUPAC is registered in Zürich, Switzerland, and the administrative office, known as the "IUPAC Secretariat", is in Research Triangle Park, North Carolina, United States. This administrative office is headed by IUPAC's executive director, currently Lynn Soby. IUPAC was established in 1919 as the successor of the International Congress of Applied Chemistry for the advancement of chemistry. Its members, the National Adhering Organizations, can be national chemistry societies, national academies of sciences, or other bodies representing chemists. There are fifty-four National Adhering Organizations and three Associate National Adhering Organizations. IUPAC's Inter-divisional Committee on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
InHg
Inch of mercury (inHg and ″Hg) is a non- SI unit of measurement for pressure. It is used for barometric pressure in weather reports, refrigeration and aviation in the United States. It is the pressure exerted by a column of mercury in height at the standard acceleration of gravity. Conversion to metric units depends on the temperature of mercury, and hence its density; typical conversion factors are: In older literature, an "inch of mercury" is based on the height of a column of mercury at .Barry N. Taylor, ''Guide for the Use of the International System of Units (SI),'' 1995, NIST Special Publication 811, Appendix /ref> :1 inHg60 °F = In Imperial units: 1 inHg60 °F = 0.489 771 Pounds per square inch, psi, or 2.041 771 inHg60 °F = 1 psi. Applications Aircraft and automobiles Aircraft altimeters measure the relative pressure difference between the lower ambient pressure at altitude and a calibrated reading on the ground. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MmHg
A millimetre of mercury is a manometric unit of pressure, formerly defined as the extra pressure generated by a column of mercury one millimetre high, and currently defined as exactly pascals. It is denoted mmHg or mm Hg. Although not an SI unit, the millimetre of mercury is still routinely used in medicine, meteorology, aviation, and many other scientific fields. One millimetre of mercury is approximately 1 Torr, which is of standard atmospheric pressure ( ≈ ). Although the two units are not equal, the relative difference (less than ) is negligible for most practical uses. History For much of human history, the pressure of gases like air was ignored, denied, or taken for granted, but as early as the 6th century BC, Greek philosopher Anaximenes of Miletus claimed that all things are made of air that is simply changed by varying levels of pressure. He could observe water evaporating, changing to a gas, and felt that this applied even to solid matter. More cond ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relative Humidity
Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present. Humidity depends on the temperature and pressure of the system of interest. The same amount of water vapor results in higher relative humidity in cool air than warm air. A related parameter is the dew point. The amount of water vapor needed to achieve saturation increases as the temperature increases. As the temperature of a parcel of air decreases it will eventually reach the saturation point without adding or losing water mass. The amount of water vapor contained within a parcel of air can vary significantly. For example, a parcel of air near saturation may contain 28 g of water per cubic metre of air at , but only 8 g of water per cubic metre of air at . Three primary measurements of humidity are widely employed: absolute, relative, and specific. Ab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pressure
Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and even by industry. Further, both spellings are often used ''within'' a particular industry or country. Industries in British English-speaking countries typically use the "gauge" spelling. is the pressure relative to the ambient pressure. Various units are used to express pressure. Some of these derive from a unit of force divided by a unit of area; the SI unit of pressure, the pascal (Pa), for example, is one newton per square metre (N/m2); similarly, the pound-force per square inch (psi) is the traditional unit of pressure in the imperial and U.S. customary systems. Pressure may also be expressed in terms of standard atmospheric pressure; the atmosphere (atm) is equal to this pressure, and the torr is defined as of this. Manometric u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
