HOME



picture info

Hygrometer
A hair tension dial hygrometer with a nonlinear scale. A hygrometer is an instrument that measures humidity: that is, how much water vapor is present. Humidity measurement instruments usually rely on measurements of some other quantities, such as temperature, pressure, mass, and mechanical or electrical changes in a substance as moisture is absorbed. By calibration and calculation, these measured quantities can be used to indicate the humidity. Modern electronic devices use the temperature of condensation (called the dew point), or they sense changes in electrical capacitance or resistance. The maximum amount of water vapor that can be present in a given volume (at saturation) varies greatly with temperature; at low temperatures a lower mass of water per unit volume can remain as vapor than at high temperatures. Thus a change in the temperature changes the relative humidity. A prototype hygrometer was invented by Leonardo da Vinci in 1480. Major improvements occurred during ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Sling Psychrometer
image:Haar-Hygrometer.jpg, A hair tension dial hygrometer with a nonlinear scale. A hygrometer is an instrument that measures humidity: that is, how much water vapor is present. Humidity measurement instruments usually rely on measurements of some other quantities, such as temperature, pressure, mass, and mechanical or electrical changes in a substance as moisture is absorbed. By calibration and calculation, these measured quantities can be used to indicate the humidity. Modern electronic devices use the temperature of condensation (called the dew point), or they sense changes in electrical capacitance or Electrical resistance, resistance. The maximum amount of water vapor that can be present in a given volume (at Relative humidity, saturation) varies greatly with temperature; at low temperatures a lower mass of water per unit volume can remain as vapor than at high temperatures. Thus a change in the temperature changes the relative humidity. A prototype hygrometer was invented b ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Water Vapor
Water vapor, water vapour, or aqueous vapor is the gaseous phase of Properties of water, water. It is one Phase (matter), state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from the Sublimation (phase transition), sublimation of ice. Water vapor is transparent, like most constituents of the atmosphere. Under typical atmospheric conditions, water vapor is continuously generated by evaporation and removed by condensation. It is less dense than most of the other constituents of air and triggers convection currents that can lead to clouds and fog. Being a component of Earth's hydrosphere and hydrologic cycle, it is particularly abundant in Earth's atmosphere, where it acts as a greenhouse gas and warming feedback, contributing more to total greenhouse effect than non-condensable gases such as carbon dioxide and methane. Use of water vapor, as steam, has been important for cooking, and as a major component in energy prod ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

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 (meteorology), 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 8 g of water per cubic metre of air at , and 28 g of water per cubic metre of air at Three primary measurements of humidity are widely employed: abso ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  




Psychrometrics
Psychrometrics (or psychrometry, ; also called hygrometry) is the field of engineering concerned with the physical and thermodynamic properties of gas-vapor mixtures. History With the inventions of the hygrometer and thermometer, the theories of combining the two began to emerge during the sixteenth and seventeenth centuries. In 1818, a German inventor, Ernst Ferdinand August (1795-1870), patented the term “psychrometer”, from the Greek language meaning “cold measure”. The psychrometer is a hygrometer, hygrometric instrument based on the principle that dry air enhances evaporation, unlike wet air, which slows it. Common applications Although the principles of psychrometry apply to any physical system consisting of gas-vapor mixtures, the most common system of interest is the mixture of water vapor and air, because of its application in HVAC, heating, ventilation, and air-conditioning and meteorology. In human terms, our thermal comfort is in large part a consequence ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


Stevenson Screen Interior
Stevenson is an English language patronymic surname meaning "son of Steven". Its first historical record is from pre-10th-century England. Another origin of the name is as a toponymic surname related to the place Stevenstone in Devon, England. There are variant spellings of the name, including Stephenson. Notable people sharing this surname include *Adonis Stevenson (born 1977), Canadian boxer *Alexander Campbell Stevenson (1802–1889), American politician and physician *Alexandra Stevenson (born 1980), American tennis player *Anne Stevenson (1933–2020), American-British poet * Anita Stevenson, English table tennis player *B. W. Stevenson (1949–1988), American country pop singer and musician *Ben Stevenson (other), multiple people *Cal Stevenson (born 1996), American baseball outfielder * Carter L. Stevenson (1817–1888), American soldier *Charles Stevenson (other), multiple people *Christine Wetherill Stevenson (1878–1922), heiress of the Pittsburgh Pai ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Evaporation
Evaporation is a type of vaporization that occurs on the Interface (chemistry), surface of a liquid as it changes into the gas phase. A high concentration of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when humidity affects rate of evaporation of water. When the molecules of the liquid collide, they transfer energy to each other based on how they collide. When a molecule near the surface absorbs enough energy to overcome the vapor pressure, it will escape and enter the surrounding air as a gas. When evaporation occurs, the energy removed from the vaporized liquid will reduce the temperature of the liquid, resulting in evaporative cooling. On average, only a fraction of the molecules in a liquid have enough heat energy to escape from the liquid. The evaporation will continue until an equilibrium is reached when the evaporation of the liquid is equal to its condensation. In an enclosed environment, a liquid will evaporate unt ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Temperature
Temperature is a physical quantity that quantitatively expresses the attribute of hotness or coldness. Temperature is measurement, measured with a thermometer. It reflects the average kinetic energy of the vibrating and colliding atoms making up a substance. Thermometers are calibrated in various temperature scales that historically have relied on various reference points and thermometric substances for definition. The most common scales are the Celsius scale with the unit symbol °C (formerly called ''centigrade''), the Fahrenheit scale (°F), and the Kelvin scale (K), with the third being used predominantly for scientific purposes. The kelvin is one of the seven base units in the International System of Units (SI). Absolute zero, i.e., zero kelvin or −273.15 °C, is the lowest point in the thermodynamic temperature scale. Experimentally, it can be approached very closely but not actually reached, as recognized in the third law of thermodynamics. It would be impossible ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


Daniell Hygrometer-MHS 2191-P4070317-gradient
Daniell is a surname. Notable people with the surname include: * Alexander Daniell (1599–1668), Cornish landowner * Alfred Daniell (1853–1937) * Ave Daniell (1914–1999), American (gridiron) footballer * Charles Daniell (1827–1889), Major-General, British Army * David Daniell (author) (1929–2016), biographer of William Tyndale * David Daniell (cyclist) (born 1989), English competitive cyclist * David Daniell (musician) (born 1972), American guitarist and composer * David Scott Daniell (1906–1965) * De'Anyers family * Edward Daniell (cricketer) (1815–1875), English cricketer * Edward Thomas Daniell (1804–1842), English landscape painter and etcher * Francis Henry Blackburne Daniell (1845–1921) was an Anglo-Irish barrister and historian * Geoffrey Daniell (1516–1586) * George Daniell (medical doctor) (1864–1937), medical practitioner and anaesthesiologist * George Daniell (photographer) (1911–2002), American photographer * George Daniell (priest) ( ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Meteorology
Meteorology is the scientific study of the Earth's atmosphere and short-term atmospheric phenomena (i.e. weather), with a focus on weather forecasting. It has applications in the military, aviation, energy production, transport, agriculture, construction, weather warnings and disaster management. Along with climatology, atmospheric physics and atmospheric chemistry, meteorology forms the broader field of the atmospheric sciences. The interactions between Earth's atmosphere and its oceans (notably El Niño and La Niña) are studied in the interdisciplinary field of hydrometeorology. Other interdisciplinary areas include biometeorology, space weather and planetary meteorology. Marine weather forecasting relates meteorology to maritime and coastal safety, based on atmospheric interactions with large bodies of water. Meteorologists study meteorological phenomena driven by solar radiation, Earth's rotation, ocean currents and other factors. These include everyday ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]  


picture info

Heating, Ventilation, And Air Conditioning
Heating, ventilation, and air conditioning (HVAC ) is the use of various technologies to control the temperature, humidity, and purity of the air in an enclosed space. Its goal is to provide thermal comfort and acceptable indoor air quality. HVAC system design is a subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics, and heat transfer. "Refrigeration" is sometimes added to the field's abbreviation as HVAC&R or HVACR, or "ventilation" is dropped, as in HACR (as in the designation of HACR-rated circuit breakers). HVAC is an important part of residential structures such as single family homes, apartment buildings, hotels, and senior living facilities; medium to large industrial and office buildings such as skyscrapers and hospitals; vehicles such as cars, trains, airplanes, ships and submarines; and in marine environments, where safe and Sick building syndrome, healthy building conditions are regulated with respect to temperature and ...
[...More Info...]      
[...Related Items...]     OR:     [Wikipedia]   [Google]   [Baidu]