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Deuterium-depleted Water
Deuterium-depleted water (DDW) is water which has a lower concentration of deuterium than occurs naturally at sea level on Earth. DDW is sometimes known as light water, although " light water" has long referred to ordinary water, specifically in nuclear reactors. Chemistry Deuterium-depleted water has a lower concentration of deuterium (2H) than occurs in nature at sea level. Deuterium is a naturally-occurring, stable (non-radioactive) isotope of hydrogen with a nucleus consisting of one proton and one neutron. The nucleus of ordinary hydrogen ( protium) consists of one proton only, and no neutron. Deuterium atoms have about twice the atomic mass of normal hydrogen atoms as a result. Heavy water consists of water molecules with two deuterium atoms instead of the two normal hydrogen atoms. The hydrogen in normal water consists of about 99.98% (by weight) of normal hydrogen (1H). The production of heavy water involves isolating and removing deuterium-containing isotopologues wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water
Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a solvent). It is vital for all known forms of life, despite not providing food, energy or organic micronutrients. Its chemical formula, H2O, indicates that each of its molecules contains one oxygen and two hydrogen atoms, connected by covalent bonds. The hydrogen atoms are attached to the oxygen atom at an angle of 104.45°. "Water" is also the name of the liquid state of H2O at standard temperature and pressure. A number of natural states of water exist. It forms precipitation in the form of rain and aerosols in the form of fog. Clouds consist of suspended droplets of water and ice, its solid state. When finely divided, crystalline ice may precipitate in the form of snow. The gaseous state of water is steam or water vapor. Water co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrolysis
In chemistry and manufacturing, electrolysis is a technique that uses direct electric current (DC) to drive an otherwise non-spontaneous chemical reaction. Electrolysis is commercially important as a stage in the separation of elements from naturally occurring sources such as ores using an electrolytic cell. The voltage that is needed for electrolysis to occur is called the decomposition potential. The word "lysis" means to separate or break, so in terms, electrolysis would mean "breakdown via electricity". Etymology The word "electrolysis" was introduced by Michael Faraday in 1834, using the Greek words "amber", which since the 17th century was associated with electrical phenomena, and ' meaning "dissolution". Nevertheless, electrolysis, as a tool to study chemical reactions and obtain pure elements, precedes the coinage of the term and formal description by Faraday. History In the early nineteenth century, William Nicholson and Anthony Carlisle sought to further Volt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medical Physics
Medical physics deals with the application of the concepts and methods of physics to the prevention, diagnosis and treatment of human diseases with a specific goal of improving human health and well-being. Since 2008, medical physics has been included as a health profession according to International Standard Classification of Occupation of the International Labour Organization. Although medical physics may sometimes also be referred to as ''biomedical physics'', ''medical biophysics'', ''applied physics in medicine'', ''physics applications in medical science'', ''radiological physics'' or ''hospital radio-physics'', however a "medical physicist" is specifically a health professional with specialist education and training in the concepts and techniques of applying physics in medicine and competent to practice independently in one or more of the subfields of medical physics. Traditionally, medical physicists are found in the following healthcare specialties: radiation oncology (a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water Chemistry
Water chemistry analyses are carried out to identify and quantify the chemical components and properties of water samples. The type and sensitivity of the analysis depends on the purpose of the analysis and the anticipated use of the water. Chemical water analysis is carried out on water used in industrial processes, on waste-water stream, on rivers and stream, on rainfall and on the sea. In all cases the results of the analysis provides information that can be used to make decisions or to provide re-assurance that conditions are as expected. The analytical parameters selected are chosen to be appropriate for the decision making process or to establish acceptable normality. Water chemistry analysis is often the groundwork of studies of water quality, pollution, hydrology and geothermal waters. Analytical methods routinely used can detect and measure all the natural elements and their inorganic compounds and a very wide range of organic chemical species using methods such as gas chr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water
Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a solvent). It is vital for all known forms of life, despite not providing food, energy or organic micronutrients. Its chemical formula, H2O, indicates that each of its molecules contains one oxygen and two hydrogen atoms, connected by covalent bonds. The hydrogen atoms are attached to the oxygen atom at an angle of 104.45°. "Water" is also the name of the liquid state of H2O at standard temperature and pressure. A number of natural states of water exist. It forms precipitation in the form of rain and aerosols in the form of fog. Clouds consist of suspended droplets of water and ice, its solid state. When finely divided, crystalline ice may precipitate in the form of snow. The gaseous state of water is steam or water vapor. Water co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Properties Of Water
Water () is a polar inorganic compound that is at room temperature a tasteless and odorless liquid, which is nearly colorless apart from an inherent hint of blue. It is by far the most studied chemical compound and is described as the "universal solvent" and the "solvent of life". It is the most abundant substance on the surface of Earth and the only common substance to exist as a solid, liquid, and gas on Earth's surface. It is also the third most abundant molecule in the universe (behind molecular hydrogen and carbon monoxide). Water molecules form hydrogen bonds with each other and are strongly polar. This polarity allows it to dissociate ions in salts and bond to other polar substances such as alcohols and acids, thus dissolving them. Its hydrogen bonding causes its many unique properties, such as having a solid form less dense than its liquid form, a relatively high boiling point of 100 °C for its molar mass, and a high heat capacity. Water is amphoteric, meani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light Water (other)
Light water or Lightwater may refer to: Science * Deuterium-depleted water, which has a lower concentration of deuterium than occurs naturally on Earth * Water, especially water that is not heavy water ** Water, the coolant in a light-water reactor type of nuclear reactor Other uses * Lightwater, a town in Surrey, England See also * Semiheavy water Semiheavy water is the result of replacing one of the protium in light water with deuterium. It exists whenever there is water with light hydrogen ( protium, 1H) and deuterium (D or 2H) in the mix. This is because hydrogen atoms (hydrogen-1 and ..., the result of replacing one of the protium in light water to deuterium * Heavy water, a form of water that contains a larger than normal amount of the hydrogen isotope deuterium {{disambiguation, geo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kinetic Isotope Effect
In physical organic chemistry, a kinetic isotope effect (KIE) is the change in the reaction rate of a chemical reaction when one of the atoms in the reactants is replaced by one of its isotopes. Formally, it is the ratio of rate constants for the reactions involving the light (''kL'') and the heavy (''kH'') isotopically substituted reactants (isotopologues): :\text=\frac This change in reaction rate is a quantum mechanical effect that primarily results from heavier isotopologues having lower vibrational frequencies compared to their lighter counterparts. In most cases, this implies a greater energetic input needed for heavier isotopologues to reach the transition state (or, in rare cases, the dissociation limit), and consequently, a slower reaction rate. The study of kinetic isotope effects can help the elucidation of the reaction mechanism of certain chemical reactions and is occasionally exploited in drug development to improve unfavorable pharmacokinetics by protecting m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Efficacy
Efficacy is the ability to perform a task to a satisfactory or expected degree. The word comes from the same roots as ''effectiveness'', and it has often been used synonymously, although in pharmacology a pragmatic clinical trial#Efficacy versus effectiveness, distinction is now often made between efficacy and effectiveness. The word ''efficacy'' is used in pharmacology and medicine to refer both to the maximum response achievable from a pharmaceutical drug in research settings, and to the capacity for sufficient therapeutic effect or beneficial change in clinical settings. Pharmacology In pharmacology, efficacy () is the maximum response achievable from an applied or dosed agent, for instance, a small molecule drug. Intrinsic activity is a relative term for a drug's efficacy relative to a drug with the highest observed efficacy. It is a purely descriptive term that has little or no mechanistic interpretation. In order for a drug to have an effect, it needs to bind to its t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skeptical Inquirer
''Skeptical Inquirer'' is a bimonthly American general-audience magazine published by the Committee for Skeptical Inquiry (CSI) with the subtitle: ''The Magazine for Science and Reason''. Mission statement and goals Daniel Loxton, writing in 2013 about the mission and goals of the skeptical movement, criticized the idea that people wanted to read about the paranormal, Uri Geller and crystal skulls not being relevant any longer. Paul Kurtz in 2009 seemed to share this sentiment and stated that the organization would still research some paranormal subjects as they have expertise in this area, but they would begin to investigate other areas. S.I. "has reached an historic juncture: the recognition that there is a critical need to change our direction." While editor Frazier did expand the scope of the magazine to include topics less paranormal and more that were an attack on science and critical thinking such as climate change denialism, conspiracy theories and the influence of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harriet Hall
Harriet A. Hall (born July 2, 1945) is a U.S. retired family physician, former U.S. Air Force flight surgeon and skeptic who writes about alternative medicine and quackery for ''Skeptic'' and ''Skeptical Inquirer''. She writes under the name The SkepDoc. Career Hall received her B.A. and M.D. from the University of Washington. She was only the second woman to do her internship in the Air Force and was the first female graduate of the Air Force family to practice residency at Eglin Air Force Base. Hall says she was a "passive skeptic" for quite some time, only reading the literature and attending the various meetings. She met Wallace Sampson at the Skeptic's Toolbox workshop in Oregon. He convinced her to write an article for the ''Scientific Review of Alternative Medicine'' (Interview from 16:08 to 33:25) testing so-called "Vitamin O" products she had seen advertised in the mail. She then began writing articles for ''Skeptical Inquirer''. When she spoke to Michael Shermer at The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catalytic
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quickly, very small amounts of catalyst often suffice; mixing, surface area, and temperature are important factors in reaction rate. Catalysts generally react with one or more reactants to form intermediates that subsequently give the final reaction product, in the process of regenerating the catalyst. Catalysis may be classified as either homogeneous, whose components are dispersed in the same phase (usually gaseous or liquid) as the reactant, or heterogeneous, whose components are not in the same phase. Enzymes and other biocatalysts are often considered as a third category. Catalysis is ubiquitous in chemical industry of all kinds. Estimates are that 90% of all commercially produced chemical products involve catalysts at some stag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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