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Ebulliometer
An ebulliometer is designed to accurately measure the boiling point of liquids by measuring the temperature of the vapor–liquid equilibrium either isobarically or isothermally. The primary components in a Świętosławski ebulliometer, which operates isobarically, are the boiler, the Cottrell pumps, the thermowell, and the condenser. Such an ebulliometer can be used for extremely accurate measurements of boiling temperature, molecular weights, mutual solubilities, and solvent purities by using a resistance thermometer (RTD) to measure the near-equilibrium conditions of the thermowell. The ebulliometer is frequently used for measuring the alcohol content of dry wines. See also Sweetness of wine and Oechsle scale The Oechsle scale is a hydrometer scale measuring the density of grape must, which is an indication of grape ripeness and sugar content used in wine-making. It is named for Ferdinand Oechsle (1774–1852) and it is widely used in the German, Swiss .... References * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boiling Point
The boiling point of a substance is the temperature at which the vapor pressure of a liquid equals the pressure surrounding the liquid and the liquid changes into a vapor. The boiling point of a liquid varies depending upon the surrounding environmental pressure. A liquid in a partial vacuum has a lower boiling point than when that liquid is at atmospheric pressure. A liquid at low pressure has a lower boiling point than when that liquid is at atmospheric pressure. Because of this, water boils at under standard pressure at sea level, but at at altitude. For a given pressure, different liquids will boiling, boil at different temperatures. The normal boiling point (also called the atmospheric boiling point or the atmospheric pressure boiling point) of a liquid is the special case in which the vapor pressure of the liquid equals the defined atmospheric pressure at sea level, one Atmosphere (unit), atmosphere. At that temperature, the vapor pressure of the liquid becomes suffici ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wojciech Świętosławski
Wojciech Alojzy Świętosławski (1881 – 1968) was a Polish physical chemist, who is considered the "father of modern thermochemistry". He developed a static method of cryometric measurement and a new method of testing coal. Świętosławski was Vice-Chairman of the International Union of Pure and Applied Chemistry (IUPAC) and created the foundations for a new branch of physical chemistry: polyazeotropy. In 1933 he became a member of the Temporary Scientific and Advisory Committee Early Years Świętosławski was born on 21 June 1881 in the village of Kiryjowka, Podolian Governorate, Russian Empire. He spent his early years in Kiev, where he graduated from high school (1899). In 1906, he graduated with an engineering degree at Chemistry Department of Kiev Technical University. His first research paper, "Thermochemical Analysis of Organic Compounds" was published in 1908, in "Polish Yearly Magazine ("Rocznik Polski"). In appreciation of his work, Świętosławski was awarded t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isobarically
In thermodynamics, an isobaric process is a type of thermodynamic process in which the pressure of the system stays constant: Δ''P'' = 0. The heat transferred to the system does work, but also changes the internal energy (''U'') of the system. This article uses the physics sign convention for work, where positive work is work done by the system. Using this convention, by the first law of thermodynamics, : Q = \Delta U + W\, where ''W'' is work, ''U'' is internal energy, and ''Q'' is heat. Pressure-volume work by the closed system is defined as: :W = \int \! p \,dV \, where Δ means change over the whole process, whereas ''d'' denotes a differential. Since pressure is constant, this means that : W = p \Delta V\, . Applying the ideal gas law, this becomes : W = n\,R\,\Delta T with ''R'' representing the gas constant, and ''n'' representing the amount of substance, which is assumed to remain constant (e.g., there is no phase transition during a chemical react ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isothermally
In thermodynamics, an isothermal process is a type of thermodynamic process in which the temperature ''T'' of a system remains constant: Δ''T'' = 0. This typically occurs when a system is in contact with an outside thermal reservoir, and a change in the system occurs slowly enough to allow the system to be continuously adjusted to the temperature of the reservoir through heat exchange (see quasi-equilibrium). In contrast, an ''adiabatic process'' is where a system exchanges no heat with its surroundings (''Q'' = 0). Simply, we can say that in an isothermal process * T = \text * \Delta T = 0 * dT = 0 * For ideal gases only, internal energy \Delta U = 0 while in adiabatic processes: * Q = 0. Etymology The adjective "isothermal" is derived from the Greek words "ἴσος" ("isos") meaning "equal" and "θέρμη" ("therme") meaning "heat". Examples Isothermal processes can occur in any kind of system that has some means of regulating the temperature, including ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frederick Gardner Cottrell
Frederick Gardner Cottrell (January 10, 1877 – November 16, 1948) was an American physical chemist, inventor and philanthropist. He is best known for his invention of the electrostatic precipitator, one of the first inventions designed to eliminate air pollution—and for establishing the Research Corporation for Science Advancement, a foundation that has funded scientific research since 1912. Biography He was born on January 10, 1877 in Oakland, California to Henry Cottrell and Cynthia Durfee. Both prominent families going back to the settlement of America. Cottrell's immense curiosity gained him notice early in life. One acquaintance said, “He read textbooks like novels.” He finished high school at age 16, entered the University of California, Berkeley, and graduated in 3 years. After graduation, he taught chemistry at Oakland High School, saving money (his annual salary was $1,200) until he could afford to continue his formal education. A notation in his diary, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermowell
Thermowells are cylindrical fittings used to protect temperature sensors installed in industrial processes. A thermowell consists of a tube closed at one end and mounted in the process stream. A temperature sensor such as a thermometer, thermocouple, or resistance temperature detector is inserted in the open end of the tube, which is usually in the open air outside the process piping or vessel and any thermal insulation. Thermodynamically, the process fluid transfers heat to the thermowell wall, which in turn transfers heat to the sensor. Since more mass is present with a sensor-well assembly than with a probe directly immersed into the process, the sensor's response to process temperature changes is slowed by the addition of the well. If the sensor fails, it can be easily replaced without draining the vessel or piping. Since the mass of the thermowell must be heated to the process temperature, and since the walls of the thermowell conduct heat out of the process, sensor accuracy a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Resistance Thermometer
Resistance thermometers, also called resistance temperature detectors (RTDs), are sensors used to measure temperature. Many RTD elements consist of a length of fine wire wrapped around a heat-resistant ceramic or glass core but other constructions are also used. The RTD wire is a pure material, typically platinum (Pt), nickel (Ni), or copper (Cu). The material has an accurate resistance/temperature relationship which is used to provide an indication of temperature. As RTD elements are fragile, they are often housed in protective probes. RTDs, which have higher accuracy and repeatability, are slowly replacing thermocouples in industrial applications below 600 ° C. Resistance/temperature relationship of metals Common RTD sensing elements for biomedical application constructed of platinum (Pt), nickel (Ni), or copper (Cu) have a repeatable resistance versus temperature relationship (''R'' vs ''T'') and operating temperature range. The ''R'' vs ''T'' relationship is defin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sweetness Of Wine
The subjective sweetness of a wine is determined by the interaction of several factors, including the amount of sugar in the wine, but also the relative levels of alcohol, acids, and tannins. Sugars and alcohol enhance a wine's sweetness, while acids cause sourness and bitter tannins cause bitterness. These principles are outlined in the 1987 work by Émile Peynaud, ''The Taste of Wine''. History ''Vintage: The Story of Wine'', a book authored by British wine writer Hugh Johnson, presents several methods that have been used throughout history to sweeten wine. The most common way was to harvest the grapes as late as possible. This method was advocated by Virgil and Martial in Roman times. In contrast, the ancient Greeks would harvest the grapes early, to preserve some of their acidity, and then leave them in the sun for a few days to allow them to shrivel and concentrate the sugar. In Crete, a similar effect was achieved by twisting the stalks of the grape to deprive them of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oechsle Scale
The Oechsle scale is a hydrometer scale measuring the density of grape must, which is an indication of grape ripeness and sugar content used in wine-making. It is named for Ferdinand Oechsle (1774–1852) and it is widely used in the German, Swiss and Luxembourgish wine-making industries. On the Oechsle scale, one degree Oechsle (°Oe) corresponds to one gram of the difference between the mass of one litre of must at 20 °C and 1 kg (the mass of 1 litre of water). For example, must with a specific mass of 1084 grams per litre has 84 °Oe. Overview The mass difference between equivalent volumes of must and water is almost entirely due to the dissolved sugar in the must. Since the alcohol in wine is produced by fermentation of the sugar, the Oechsle scale is used to predict the maximal possible alcohol content of the finished wine. This measure is commonly used to select when to harvest grapes. In the vineyard, the must density is usually measured by using a refractometer by c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laboratory Equipment
A laboratory (; ; colloquially lab) is a facility that provides controlled conditions in which scientific or technological research, experiments, and measurement may be performed. Laboratory services are provided in a variety of settings: physicians' offices, clinics, hospitals, and regional and national referral centers. Overview The organisation and contents of laboratories are determined by the differing requirements of the specialists working within. A physics laboratory might contain a particle accelerator or vacuum chamber, while a metallurgy laboratory could have apparatus for casting or refining metals or for testing their strength. A chemist or biologist might use a wet laboratory, while a psychologist's laboratory might be a room with one-way mirrors and hidden cameras in which to observe behavior. In some laboratories, such as those commonly used by computer scientists, computers (sometimes supercomputers) are used for either simulations or the analysis of data. Scien ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Science And Technology In Poland
Education has been of prime interest to Poland's rulers since the early 12th century. The catalog of the library of the Cathedral Chapter in Kraków dating from 1110 shows that Polish scholars already then had access to western European literature. In 1364, King Kazimierz the Great founded the Cracow Academy, which would become one of the great universities of Europe. The Polish people have made considerable contributions in the fields of science, technology and mathematics. The list of famous scientists in Poland begins in earnest with the polymath, astronomer and mathematician Nicolaus Copernicus, who formulated the heliocentric theory and made an important contribution to the scientific revolution. In 1773 King Stanisław August Poniatowski established the Commission of National Education, the world's first ministry of education. After the third partition of Poland, in 1795, no Polish state existed. The 19th and 20th centuries saw many Polish scientists working abroad. One of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
