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Mechanosynthesis
Mechanosynthesis is a term for hypothetical chemical syntheses in which reaction outcomes are determined by the use of mechanical constraints to direct reactive molecules to specific molecular sites. There are presently no non-biological chemical syntheses which achieve this aim. Some atomic placement has been achieved with scanning tunnelling microscopes. Introduction In conventional chemical synthesis or chemosynthesis, reactive molecules encounter one another through random thermal motion in a liquid or vapor. In a hypothesized process of mechanosynthesis, reactive molecules would be attached to molecular mechanical systems, and their encounters would result from mechanical motions bringing them together in planned sequences, positions, and orientations. It is envisioned that mechanosynthesis would avoid unwanted reactions by keeping potential reactants apart, and would strongly favor desired reactions by holding reactants together in optimal orientations for many molecular ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Nanotechnology
Molecular nanotechnology (MNT) is a technology based on the ability to build structures to complex, atomic specifications by means of mechanosynthesis. This is distinct from nanoscale materials. Based on Richard Feynman's vision of miniature factories using nanomachines to build complex products ( including additional nanomachines), this advanced form of nanotechnology (or ''molecular manufacturing'') would make use of positionally-controlled mechanosynthesis guided by molecular machine systems. MNT would involve combining physical principles demonstrated by biophysics, chemistry, other nanotechnologies, and the molecular machinery of life with the systems engineering principles found in modern macroscale factories. Introduction While conventional chemistry uses inexact processes obtaining inexact results, and biology exploits inexact processes to obtain definitive results, molecular nanotechnology would employ original definitive processes to obtain definitive results. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanofactory
A molecular assembler, as defined by K. Eric Drexler, is a "proposed device able to guide chemical reactions by positioning reactive molecules with atomic precision". A molecular assembler is a kind of molecular machine. Some biological molecules such as ribosomes fit this definition. This is because they receive instructions from messenger RNA and then assemble specific sequences of amino acids to construct protein molecules. However, the term "molecular assembler" usually refers to theoretical human-made devices. Beginning in 2007, the British Engineering and Physical Sciences Research Council has funded development of ribosome-like molecular assemblers. Clearly, molecular assemblers are possible in this limited sense. A technology roadmap project, led by the Battelle Memorial Institute and hosted by several U.S. National Laboratories has explored a range of atomically precise fabrication technologies, including both early-generation and longer-term prospects for programma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mechanochemistry
Mechanochemistry (or mechanical chemistry) is the initiation of chemical reactions by mechanical phenomena. Mechanochemistry thus represents a fourth way to cause chemical reactions, complementing thermal reactions in fluids, photochemistry, and electrochemistry. Conventionally mechanochemistry focuses on the transformations of covalent bonds by mechanical force. Not covered by the topic are many phenomena: phase transitions, dynamics of biomolecules (docking, folding), and sonochemistry. Mechanochemistry is not the same as mechanosynthesis, which refers specifically to the machine-controlled construction of complex molecular products. In natural environments, mechanochemical reactions are frequently induced by physical processes such as earthquakes, glacier movement or hydraulic action of rivers or waves. In extreme environments such as subglacial lakes, hydrogen generated by mechnochemical reactions involving crushed silicate rocks and water can support methanogenic microbial com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Synthesis
As a topic of chemistry, chemical synthesis (or combination) is the artificial execution of chemical reactions to obtain one or several products. This occurs by physical and chemical manipulations usually involving one or more reactions. In modern laboratory uses, the process is reproducible and reliable. A chemical synthesis involves one or more compounds (known as '' reagents'' or ''reactants'') that will experience a transformation when subjected to certain conditions. Various reaction types can be applied to formulate a desired product. This requires mixing the compounds in a reaction vessel, such as a chemical reactor or a simple round-bottom flask. Many reactions require some form of processing (" work-up") or purification procedure to isolate the final product. The amount produced by chemical synthesis is known as the ''reaction yield''. Typically, yields are expressed as a mass in grams (in a laboratory setting) or as a percentage of the total theoretical quantity that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Society
The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, recognising excellence in science, supporting outstanding science, providing scientific advice for policy, education and public engagement and fostering international and global co-operation. Founded on 28 November 1660, it was granted a royal charter by King Charles II as The Royal Society and is the oldest continuously existing scientific academy in the world. The society is governed by its Council, which is chaired by the Society's President, according to a set of statutes and standing orders. The members of Council and the President are elected from and by its Fellows, the basic members of the society, who are themselves elected by existing Fellows. , there are about 1,700 fellows, allowed to use the postnominal title FRS (Fellow of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bhopal Disaster
The Bhopal disaster, also referred to as the Bhopal gas tragedy, was a chemical accident on the night of 2–3 December 1984 at the Union Carbide India Limited (UCIL) pesticide plant in Bhopal, Madhya Pradesh, India. Considered the world's worst industrial disaster, over 500,000 people in the small towns around the plant were exposed to the highly toxic gas methyl isocyanate (). Estimates vary on the death toll, with the official number of immediate deaths being 2,259. In 2008, the Government of Madhya Pradesh paid compensation to the family members of 3,787 victims killed in the gas release, and to 574,366 injured victims. A government affidavit in 2006 stated that the leak caused 558,125 injuries, including 38,478 temporary partial injuries and approximately 3,900 severely and permanently disabling injuries. Others estimate that 8,000 died within two weeks, and another 8,000 or more have since died from gas-related diseases. The owner of the factory, UCIL, was majority owned ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecophagy
Ecophagy is a term coined by Robert Freitas that means the literal consumption of an ecosystem. It derives from the Greek "οἶκος" (), which refers to a "house" or "household", and the Greek "φαγεῖν" (), "to eat". Freitas used the term to describe a scenario involving molecular nanotechnology gone awry. In this situation (called the grey goo scenario) out-of-control self-replicating nanorobots consume entire ecosystems, resulting in global ecophagy. However, the word "ecophagy" is now applied more generally in reference to any event—nuclear war, the spread of monoculture, massive species extinctions—that might fundamentally alter the planet. Scholars suggest that these events might result in ecocide in that they would undermine the capacity of the Earth's biological population to repair itself. Others suggest that more mundane and less spectacular events—the unrelenting growth of the human population, the steady transformation of the natural world by human bein ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grey Goo
Gray goo (also spelled as grey goo) is a hypothetical global catastrophic scenario involving molecular nanotechnology in which out-of-control self-replicating machines consume all biomass on Earth while building many more of themselves, a scenario that has been called ''ecophagy'' (the literal consumption of the ecosystem). The original idea assumed machines were designed to have this capability, while popularizations have assumed that machines might somehow gain this capability by accident. Self-replicating machines of the macroscopic variety were originally described by mathematician John von Neumann, and are sometimes referred to as von Neumann machines or clanking replicators. The term ''gray goo'' was coined by nanotechnology pioneer K. Eric Drexler in his 1986 book '' Engines of Creation''. In 2004, he stated "I wish I had never used the term 'gray goo'." ''Engines of Creation'' mentions "gray goo" as a thought experiment in two paragraphs and a note, while the popular ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Society's Nanotech Report
The impact of nanotechnology extends from its medical, ethical, mental, legal and environmental applications, to fields such as engineering, biology, chemistry, computing, materials science, and communications. Major benefits of nanotechnology include improved manufacturing methods, water purification systems, energy systems, physical enhancement, nanomedicine, better food production methods, nutrition and large-scale infrastructure auto-fabrication. Nanotechnology's reduced size may allow for automation of tasks which were previously inaccessible due to physical restrictions, which in turn may reduce labor, land, or maintenance requirements placed on humans. Potential risks include environmental, health, and safety issues; transitional effects such as displacement of traditional industries as the products of nanotechnology become dominant, which are of concern to privacy rights advocates. These may be particularly important if potential negative effects of nanoparticles are ov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Academy Of Engineering
The Royal Academy of Engineering (RAEng) is the United Kingdom's national academy of engineering. The Academy was founded in June 1976 as the Fellowship of Engineering with support from Prince Philip, Duke of Edinburgh, who became the first senior fellow and remained so until his death. The Fellowship was incorporated and granted a royal charter on 17 May 1983 and became the Royal Academy of Engineering on 16 March 1992. It is governed according to the charter and associated statutes and regulations (as amended from time to time). History Conceived in the late 1960s, during the Apollo space program and Harold Wilson's espousal of "white heat of technology", the Fellowship of Engineering was born in the year of Concorde's first commercial flight. The Fellowship's first meeting, at Buckingham Palace on 11 June 1976, enrolled 126 of the UK's leading engineers. The first fellows included Air Commodore Sir Frank Whittle, the jet engine developer, the structural engineer Sir Ove Arup ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Industrial Accident
A work accident, workplace accident, occupational accident, or accident at work is a "discrete occurrence in the course of work" leading to physical or mental occupational injury. According to the International Labour Organization (ILO), more than 337 million accidents happen on the job each year, resulting, together with occupational diseases, in more than 2.3 million deaths annually. The phrase "in the course of work" can include work-related accidents happening off the company's premises, and can include accidents caused by third parties, according to Eurostat. The definition of work accident includes accidents occurring "while engaged in an economic activity, or at work, or carrying on the business of the employer" according to the ILO. The phrase "physical or mental harm" means any injury, disease, or death. Occupational accidents differ from occupational diseases as accidents are unexpected and unplanned occurrences (e.g., mine collapse), while occupational diseases are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dimer (chemistry)
A dimer () ('' di-'', "two" + ''-mer'', "parts") is an oligomer consisting of two monomers joined by bonds that can be either strong or weak, covalent or intermolecular. Dimers also have significant implications in polymer chemistry, inorganic chemistry, and biochemistry. The term ''homodimer'' is used when the two molecules are identical (e.g. A–A) and ''heterodimer'' when they are not (e.g. A–B). The reverse of dimerization is often called dissociation. When two oppositely charged ions associate into dimers, they are referred to as ''Bjerrum pairs'', after Niels Bjerrum. Noncovalent dimers Anhydrous carboxylic acids form dimers by hydrogen bonding of the acidic hydrogen and the carbonyl oxygen. For example, acetic acid forms a dimer in the gas phase, where the monomer units are held together by hydrogen bonds. Under special conditions, most OH-containing molecules form dimers, e.g. the water dimer. Excimers and exciplexes are excited structures with a short lifetime. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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