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Gravimetric analysis Slow addition of precipitating agent to keep Q as low as possible c. Stirring the solution during addition of precipitating agent to avoid concentration sites and keep Q low d. Increase solubility by precipitation from hot solution e. Adjust the pH to increase S, but not too much increase np as we ... | https://en.wikipedia.org/wiki?curid=659899 |
Gravimetric analysis Particle coagulation can be forced by either digestion or addition of a high concentration of a diverse ions strong electrolytic solution in order to shield the charges on colloidal particles and force agglomeration. Usually, coagulated particles return to the colloidal state if washed with water, ... | https://en.wikipedia.org/wiki?curid=659899 |
Gravimetric analysis For example, to precipitate iron as the hydroxide, we dissolve urea in the sample. Heating of the solution generates hydroxide ions from the hydrolysis of urea. Hydroxide ions are generated at all points in solution and thus there are no sites of concentration. We can also adjust the rate of urea h... | https://en.wikipedia.org/wiki?curid=659899 |
Acid–base titration An acid–base titration is a method of quantitative analysis for determining the concentration of an acid or base by exactly neutralizing it with a standard solution of base or acid having known concentration. A pH indicator is used to monitor the progress of the acid–base reaction. If the acid disso... | https://en.wikipedia.org/wiki?curid=659902 |
Acid–base titration If both are of equal strength, then the equivalence pH will be neutral. However, weak acids are not often titrated against weak bases because the colour change shown with the indicator is often quick, and therefore very difficult for the observer to see the change of colour. The point at which the i... | https://en.wikipedia.org/wiki?curid=659902 |
Acid–base titration These graphical solution methods are simple to implement, however they are infrequently used. Simple analytical formulas for the titration of N-protic acids. Valid for any number of N: 1-monoprotic, 2-diprotic until N=6 (e.g. EDTA). | https://en.wikipedia.org/wiki?curid=659902 |
R. Stephen Berry (born 1931 in Denver, Colorado) is a U.S. professor of physical chemistry. He is the James Franck Distinguished Service Professor Emeritus at The University of Chicago. He was also Special Advisor for National Security to the Director, at Argonne National Laboratory. Berry joined the Chicago faculty in... | https://en.wikipedia.org/wiki?curid=660207 |
R. Stephen Berry He then went on to study alkali halides in the gas phase, first at the University of Michigan and then at Yale, using shock waves to produce sufficient dissociation of the molecules to ions to make it feasible to observe the photodetachment spectra of the halide ions, thus determining the electron affi... | https://en.wikipedia.org/wiki?curid=660207 |
R. Stephen Berry This work, in turn, stimulated what has become known as "finite-time thermodynamics," the study of the optimal performance of processes constrained to operate in finite time or at nonzero rates. He has been very active in the study of atomic and molecular clusters, particularly in their phases and phas... | https://en.wikipedia.org/wiki?curid=660207 |
Carbaryl (1-naphthyl methylcarbamate) is a chemical in the carbamate family used chiefly as an insecticide. It is a white crystalline solid commonly sold under the brand name Sevin, a trademark of the Bayer Company. Union Carbide discovered carbaryl and introduced it commercially in 1958. Bayer purchased Aventis CropSc... | https://en.wikipedia.org/wiki?curid=661633 |
Carbaryl They interfere with the cholinergic nervous system and cause death because the effects of the neurotransmitter acetylcholine cannot be terminated by carbamoylated acetylcholinesterase. The development of the carbamate insecticides has been called a major breakthrough in pesticides. The carbamates do not have t... | https://en.wikipedia.org/wiki?curid=661633 |
Bravais lattice In geometry and crystallography, a Bravais lattice, named after , is an infinite array of discrete points generated by a set of discrete translation operations described in three dimensional space by: where "n" are any integers and a are "primitive vectors" which lie in different directions (not necessa... | https://en.wikipedia.org/wiki?curid=661808 |
Bravais lattice The unit cells are specified according to the relative lengths of the cell edges ("a" and "b") and the angle between them ("θ"). The area of the unit cell can be calculated by evaluating the norm , where a and b are the lattice vectors. The properties of the crystal families are given below: In three-di... | https://en.wikipedia.org/wiki?curid=661808 |
Bravais lattice Ten Bravais lattices split into enantiomorphic pairs. | https://en.wikipedia.org/wiki?curid=661808 |
Silicon-germanium SiGe ( or ), or silicon-germanium, is an alloy with any molar ratio of silicon and germanium, i.e. with a molecular formula of the form SiGe. It is commonly used as a semiconductor material in integrated circuits (ICs) for heterojunction bipolar transistors or as a strain-inducing layer for CMOS trans... | https://en.wikipedia.org/wiki?curid=662175 |
Silicon-germanium In July 2015, IBM announced that it had created working samples of transistors using a 7 nm silicon-germanium process, promising a quadrupling in the amount of transistors compared to a contemporary process. SiGe allows CMOS logic to be integrated with heterojunction bipolar transistors, making it sui... | https://en.wikipedia.org/wiki?curid=662175 |
Two-phase flow In fluid mechanics, two-phase flow is a flow of gas and liquid — a particular example of multiphase flow. can occur in various forms, such as flows transitioning from pure liquid to vapor as a result of external heating, separated flows, and dispersed two-phase flows where one phase is present in the for... | https://en.wikipedia.org/wiki?curid=663039 |
Two-phase flow Here a pump is operating close to the vapor pressure of the fluid being pumped. If pressure drops further, which can happen locally near the vanes for the pump, for example, then a phase change can occur and gas will be present in the pump. Similar effects can also occur on marine propellors; wherever it... | https://en.wikipedia.org/wiki?curid=663039 |
Two-phase flow Several features make two-phase flow an interesting and challenging branch of fluid mechanics: Gurgling is a characteristic sound made by unstable two-phase fluid flow, for example, as liquid is poured from a bottle, or during gargling. Modelling of two phase flow is still under development. Known method... | https://en.wikipedia.org/wiki?curid=663039 |
Gradient-index optics Gradient-index (GRIN) optics is the branch of optics covering optical effects produced by a gradient of the refractive index of a material. Such gradual variation can be used to produce lenses with flat surfaces, or lenses that do not have the aberrations typical of traditional spherical lenses. G... | https://en.wikipedia.org/wiki?curid=663580 |
Gradient-index optics The Earth's atmosphere acts as a GRIN lens, allowing observers to see the sun for a few minutes after it is actually below the horizon, and observers can also view stars that are below the horizon. This effect also allows for observation of electromagnetic signals from satellites after they have d... | https://en.wikipedia.org/wiki?curid=663580 |
Gradient-index optics This differs from traditional optical fibres, which rely on total internal reflection, in that all modes of the GRIN fibres propagate at the same speed, allowing for a higher temporal bandwidth for the fibre. Antireflection coatings are typically effective for narrow ranges of frequency or angle o... | https://en.wikipedia.org/wiki?curid=663580 |
Gradient-index optics This also limits the applications of the lens because it is difficult to use it to focus visible light; however, it has some usefulness in microwave applications. An inhomogeneous gradient-index lens possesses a refractive index whose change follows the function formula_1 of the coordinates of the... | https://en.wikipedia.org/wiki?curid=663580 |
Crystallographic point group In crystallography, a crystallographic point group is a set of symmetry operations, corresponding to one of the point groups in three dimensions, such that each operation would leave the structure of a crystal unchanged i.e. the same kinds of atoms would be placed in similar positions as be... | https://en.wikipedia.org/wiki?curid=663786 |
Crystallographic point group For a periodic crystal (as opposed to a quasicrystal), the group must maintain the three-dimensional translational symmetry that defines crystallinity. The point groups are named according to their component symmetries. There are several standard notations used by crystallographers, mineral... | https://en.wikipedia.org/wiki?curid=663786 |
Reciprocal lattice In physics, the reciprocal lattice represents the Fourier transform of another lattice (usually a Bravais lattice). In normal usage, the initial lattice (whose transform is represented by the reciprocal lattice) is usually a periodic spatial function in real-space and is also known as the "direct lat... | https://en.wikipedia.org/wiki?curid=664488 |
Reciprocal lattice the electronic density in an atomic crystal, can be written as a periodic function Due to the periodicity, it is useful to write formula_4 as a Fourier series Since formula_6 for any formula_7 then the last formula is true for the particular case formula_8 Therefore, formula_10, and that implies Math... | https://en.wikipedia.org/wiki?curid=664488 |
Reciprocal lattice The above definition is called the "physics" definition, as the factor of formula_23 comes naturally from the study of periodic structures. An equivalent definition, the "crystallographer's" definition, comes from defining the reciprocal lattice to be formula_24 which changes the definitions of the r... | https://en.wikipedia.org/wiki?curid=664488 |
Reciprocal lattice The cubic lattice is therefore said to be self-dual, having the same symmetry in reciprocal space as in real space. The reciprocal lattice to an FCC lattice is the body-centered cubic (BCC) lattice. Consider an FCC compound unit cell. Locate a primitive unit cell of the FCC; i.e., a unit cell with on... | https://en.wikipedia.org/wiki?curid=664488 |
Reciprocal lattice vectors a 1 = (a(3) 1/2 /2) i + (a/2) j ; a 2 = -(a(3) 1/2 /2) i + (a/2) j ve a 3 = a k From its definition we know that the vectors of the Bravais lattice must be closed under vector addition and subtraction. Thus it is sufficient to say that if we have and then the sum and difference formula_41 sat... | https://en.wikipedia.org/wiki?curid=664488 |
Reciprocal lattice One path to the reciprocal lattice of an arbitrary collection of atoms comes from the idea of scattered waves in the Fraunhofer (long-distance or lens back-focal-plane) limit as a Huygens-style sum of amplitudes from all points of scattering (in this case from each individual atom). This sum is denot... | https://en.wikipedia.org/wiki?curid=664488 |
Reciprocal lattice Since Fourier transformation is reversible, of course, this act of conversion to intensity tosses out "all except 2nd moment" (i.e. the phase) information. For the case of an arbitrary collection of atoms, the intensity reciprocal lattice is therefore: Here r is the vector separation between atom j a... | https://en.wikipedia.org/wiki?curid=664488 |
Reciprocal lattice The relation of "V" to "V" is not intrinsic; it depends on a choice of Haar measure (volume element) on "V". But given an identification of the two, which is in any case well-defined up to a scalar, the presence of "Q" allows one to speak to the dual lattice to "L" while staying within "V". In mathem... | https://en.wikipedia.org/wiki?curid=664488 |
Reciprocal lattice Reciprocal space comes into play regarding wave-mechanics: As a plane wave can be written by an oscillatory term formula_67 with wave vector formula_68 and angular frequency formula_69, it can be regarded as both a function of formula_68 and formula_71 (and the spectroscopic part as a function of bot... | https://en.wikipedia.org/wiki?curid=664488 |
Psychedelic therapy refers to therapeutic practices involving psychedelic drugs, oftentimes utilizing serotonergic psychedelics such as LSD, psilocybin, DMT, MDMA, mescaline, and 2C-B. In psychedelic therapy, in contrast to conventional psychiatric medication taken by the patient regularly or as-needed, patients genera... | https://en.wikipedia.org/wiki?curid=665323 |
Psychedelic therapy In addition to spawning six international conferences and the release of dozens of books, over 1,000 peer-reviewed clinical papers detailing the use of psychedelic compounds (administered to approximately 40,000 patients) were published by the mid-1960s. Proponents believed that psychedelic drugs fa... | https://en.wikipedia.org/wiki?curid=665323 |
Psychedelic therapy Many countries either banned LSD outright or made it extremely scarce, and, bowing to governmental concerns, Sandoz halted production of LSD in 1965. During a congressional hearing in 1966, Senator Robert Kennedy questioned the shift of opinion, stating, "Perhaps to some extent we have lost sight of... | https://en.wikipedia.org/wiki?curid=665323 |
Psychedelic therapy Despite broad prohibition, unofficial psychedelic research and therapeutic sessions continued nevertheless in the following decades. Some therapists exploited windows of opportunity preceding scheduling of particular substances or, alternatively, developed non-drug techniques such as Holotropic Brea... | https://en.wikipedia.org/wiki?curid=665323 |
Psychedelic therapy Furthermore, retrospective studies involving users of illicit drugs as voluntary subjects were conducted, allowing data to be collected on how psychedelics affect the human brain while simultaneously sidestepping bureaucratic difficulties associated with providing illegal substances to subjects. The... | https://en.wikipedia.org/wiki?curid=665323 |
Psychedelic therapy As of 2016, Johns Hopkins University and New York University have conducted large randomized, placebo-controlled studies. These two studies are some of the first large controlled studies measuring the effects of psychedelic therapy on depression and anxiety in cancer patients. Across clinician-ratin... | https://en.wikipedia.org/wiki?curid=665323 |
Psychedelic therapy Some of the well known particular psychedelic substances that have been used to this day are: LSD, DMT, psilocybin, mescaline, 2C-B, 2C-I, 5-MeO-DMT, AMT, ibogaine and DOM. In general, however, the drugs remain poorly understood. Their effects are strongly dependent on the environment in which they ... | https://en.wikipedia.org/wiki?curid=665323 |
Psychedelic therapy However, the studies that reported high success rates had insufficient controls, lacked objective measures of genuine change, and failed to conduct rigorous follow-up interviews with subjects. The lack of conclusive evidence notwithstanding, individual case reports are often dramatic. Bill Wilson, t... | https://en.wikipedia.org/wiki?curid=665323 |
Psychedelic therapy During the early 1950s and 1960s the National Institute of Mental Health sponsored the study of psychedelic drugs such as psilocybin and LSD to alleviate the debilitating anxiety and depression patients with terminal diagnoses may feel. While these early studies are hard to find, the resurgence of i... | https://en.wikipedia.org/wiki?curid=665323 |
Psychedelic therapy The Phase 2 trials of these studies consisted of 107 participants who had chronic, treatment-resistant PTSD, and had suffered from PTSD for an average of 17.8 years. Out of the 107 participants, 61% no longer qualified for PTSD after three sessions of MDMA-assisted psychotherapy two months after the... | https://en.wikipedia.org/wiki?curid=665323 |
Psychedelic therapy Psycholytic therapy involves the use of low to medium doses of psychedelic drugs, repeatedly at intervals of 1–2 weeks. The therapist is present during the peak of the experience and at other times as required, to assist the patient in processing material that arises and to offer support when necess... | https://en.wikipedia.org/wiki?curid=665323 |
Psychedelic therapy Aided by the deeply introspective state attained by the patient, the therapist assists him/her in developing a new life framework or personal philosophy that recognizes individual responsibility for change. In Germany has designed a psycholytic therapy, which was developed officially, but was used a... | https://en.wikipedia.org/wiki?curid=665323 |
Psychedelic therapy Within a structured CBT intervention and a dose of psilocybin, patients are given the opportunity to experience cognitive and emotional states that are altered. With these psychedelic effects, cognitive reframing of detrimental schemas and self-identity can be modified positively. In a MET environme... | https://en.wikipedia.org/wiki?curid=665323 |
Psychedelic therapy Developed by two London psychoanalysts, Joyce Martin and Pauline McCririck, this form of treatment is similar to psycholytic approaches as it is based largely on a psychoanalytic interpretation of abreactions produced by the treatment, but it tends to focus on those experiences in which the patient ... | https://en.wikipedia.org/wiki?curid=665323 |
Psychedelic therapy The resurgence of psychedelic drug therapy in the 21st century has to do largely with renewed public interest including recent articles in the "New Yorker", "The New York Times" and the "Wall Street Journal". A "New York Times" article titled "How Psychedelic Drugs Can Help Patients Face Death" was ... | https://en.wikipedia.org/wiki?curid=665323 |
Psychedelic therapy While typically the vacation destinations for psychedelics are based in Central and South America there is a rise in western culture taking over their traditional practices. In the Netherlands there are psychedelic society retreats that range from $500–1200 that center on a ceremony in which tourist... | https://en.wikipedia.org/wiki?curid=665323 |
United States National Chemistry Olympiad The (or USNCO) is a contest held by the American Chemical Society (ACS) used to select the four-student team that represents the United States at the International Chemistry Olympiad (IChO). Each local ACS section selects eight students (or more for larger ACS sections) to take... | https://en.wikipedia.org/wiki?curid=665574 |
United States National Chemistry Olympiad More thorough knowledge of basic theories is required, and often there are questions on less-emphasized portions of normal high school chemistry curricula, such as organic chemistry and coordination chemistry. One hour and 45 minutes (105 minutes) are allowed for this section. ... | https://en.wikipedia.org/wiki?curid=665574 |
United States National Chemistry Olympiad Therefore, the scope of the USNCO is different than the scope of what would be expected at the training camp or IChO. | https://en.wikipedia.org/wiki?curid=665574 |
Shape-memory alloy A shape-memory alloy is an alloy that can be deformed when cold but returns to its pre-deformed ("remembered") shape when heated. It may also be called memory metal, memory alloy, smart metal, smart alloy, or muscle wire. Parts made of shape-memory alloys can be lightweight, solid-state alternatives ... | https://en.wikipedia.org/wiki?curid=665728 |
Shape-memory alloy Repeated use of the shape-memory effect may lead to a shift of the characteristic transformation temperatures (this effect is known as functional fatigue, as it is closely related with a change of microstructural and functional properties of the material). The maximum temperature at which SMAs can no... | https://en.wikipedia.org/wiki?curid=665728 |
Shape-memory alloy Since these crystal structures do not have enough slip systems for easy dislocation motion, they deform by twinning—or rather, detwinning. Martensite is thermodynamically favored at lower temperatures, while austenite (B2 cubic) is thermodynamically favored at higher temperatures. Since these structu... | https://en.wikipedia.org/wiki?curid=665728 |
Shape-memory alloy Two common effects are an one-way and two-way shape memory. A schematic of the effects is shown below. The procedures are very similar: starting from martensite (a), adding a reversible deformation for the one-way effect or severe deformation with an irreversible amount for the two-way (b), heating t... | https://en.wikipedia.org/wiki?curid=665728 |
Shape-memory alloy Training implies that a shape memory can "learn" to behave in a certain way. Under normal circumstances, a shape-memory alloy "remembers" its low-temperature shape, but upon heating to recover the high-temperature shape, immediately "forgets" the low-temperature shape. However, it can be "trained" to... | https://en.wikipedia.org/wiki?curid=665728 |
Shape-memory alloy The figure above illustrates how this is possible, by relating the pseudoelastic stress-induced phase transformation to the shape memory effect temperature induced phase transformation. For a particular point on A it is possible to choose a point on the M line with a "higher" temperature, as long as... | https://en.wikipedia.org/wiki?curid=665728 |
Shape-memory alloy The key to the large strain deformations is the difference in crystal structure between the two phases. Austenite generally has a cubic structure while martensite can be monoclinic or another structure different from the parent phase, typically with lower symmetry. For a monoclinic martensitic materi... | https://en.wikipedia.org/wiki?curid=665728 |
Shape-memory alloy One can see that as you increase the operational temperature of the SMA, σ will be greater than the yield strength, σ, and superelasticity will no longer be observable. The first reported steps towards the discovery of the shape-memory effect were taken in the 1930s. According to Otsuka and Wayman, A... | https://en.wikipedia.org/wiki?curid=665728 |
Shape-memory alloy These materials are of particular interest as the magnetic response tends to be faster and more efficient than temperature-induced responses. Metal alloys are not the only thermally-responsive materials; shape-memory polymers have also been developed, and became commercially available in the late 199... | https://en.wikipedia.org/wiki?curid=665728 |
Shape-memory alloy The way in which the alloys are "trained" depends on the properties wanted. The "training" dictates the shape that the alloy will remember when it is heated. This occurs by heating the alloy so that the dislocations re-order into stable positions, but not so hot that the material recrystallizes. They... | https://en.wikipedia.org/wiki?curid=665728 |
Shape-memory alloy In numerous studies, it was emphasised that only a few of patented shape memory alloy applications are commercially successful due to material limitations combined with a lack of material and design knowledge and associated tools, such as improper design approaches and techniques used. The challenges... | https://en.wikipedia.org/wiki?curid=665728 |
Shape-memory alloy As a consequence of the increased heat transfer rate, the required current to achieve a given actuation force is increased. SMA is subject to structural fatigue – a failure mode by which cyclic loading results in the initiation and propagation of a crack that eventually results in catastrophic loss o... | https://en.wikipedia.org/wiki?curid=665728 |
Shape-memory alloy Boeing, General Electric Aircraft Engines, Goodrich Corporation, NASA, Texas A&M University and All Nippon Airways developed the Variable Geometry Chevron using a NiTi SMA. Such a variable area fan nozzle (VAFN) design would allow for quieter and more efficient jet engines in the future. In 2005 and ... | https://en.wikipedia.org/wiki?curid=665728 |
Shape-memory alloy The first high-volume product (> 5Mio actuators / year) is an automotive valve used to control low pressure pneumatic bladders in a car seat that adjust the contour of the lumbar support / bolsters. The overall benefits of SMA over traditionally-used solenoids in this application (lower noise/EMC/wei... | https://en.wikipedia.org/wiki?curid=665728 |
Shape-memory alloy One such application is Intelligent Reinforced Concrete (IRC), which incorporates SMA wires embedded within the concrete. These wires can sense cracks and contract to heal micro-sized cracks. Another application is active tuning of structural natural frequency using SMA wires to dampen vibrations. Th... | https://en.wikipedia.org/wiki?curid=665728 |
Shape-memory alloy While more costly than stainless steel, the self expanding properties of Nitinol alloys manufactured to BTR (Body Temperature Response), have provided an attractive alternative to balloon expandable devices in stent grafts where it gives the ability to adapt to the shape of certain blood vessels when... | https://en.wikipedia.org/wiki?curid=665728 |
Shape-memory alloy As the staple warms it returns to its non-malleable state and compresses the bony surfaces together to promote bone union. The range of applications for SMAs has grown over the years, a major area of development being dentistry. One example is the prevalence of dental braces using SMA technology to e... | https://en.wikipedia.org/wiki?curid=665728 |
Shape-memory alloy Sold in small round lengths for use in affixment-free bracelets. German scientists at Saarland University have produced a prototype machine that transfers heat using a nickel-titanium ("nitinol") alloy wire wrapped around a rotating cylinder. As the cylinder rotates, heat is absorbed on one side and ... | https://en.wikipedia.org/wiki?curid=665728 |
Fusel alcohol Fusel alcohols or fuselol, also sometimes called fusel oils in Europe, are mixtures of several alcohols (chiefly amyl alcohol) produced as a by-product of alcoholic fermentation. The word "Fusel" is German for "bad liquor". Whether fusel alcohol contributes to hangover symptoms is a matter of scientific d... | https://en.wikipedia.org/wiki?curid=666105 |
Fusel alcohol If desired, these heavier alcohols can be almost completely separated in a reflux still. Freeze distillation, on the other hand, does not remove fusel alcohols. Fusel alcohols are formed when fermentation occurs: | https://en.wikipedia.org/wiki?curid=666105 |
Carbamate A carbamate is a chemical compound that is formally derived from carbamic acid (NHCOOH). The term includes organic compounds (e.g., the ester ethyl carbamate), formally obtained by replacing one or more of the hydrogen atoms by other organic functional groups; as well as salts with the carbamate anion (e.g. a... | https://en.wikipedia.org/wiki?curid=666459 |
Carbamate They help to stabilise the protein when it becomes deoxyhemoglobin, and increases the likelihood of the release of remaining oxygen molecules bound to the protein. This stabilizing effect should not be confused with the Bohr effect (an indirect effect caused by carbon dioxide). The ε-amino groups of the lysin... | https://en.wikipedia.org/wiki?curid=666459 |
Carbamate The "urethane" in the name "polyurethane" refers to these carbamate groups; the term "urethane links" describe how carbamates polymerize. In contrast, the substance commonly called "urethane", ethyl carbamate, is neither a component of polyurethanes, nor is it used in their manufacture. Urethanes are usually ... | https://en.wikipedia.org/wiki?curid=666459 |
Carbamate While the carbamate acetylcholinesterase inhibitors are commonly referred to as "carbamate insecticides" due to their generally high selectivity for insect acetylcholinesterase enzymes over the mammalian versions, the most potent compounds such as aldicarb and carbofuran are still capable of inhibiting mammal... | https://en.wikipedia.org/wiki?curid=666459 |
Carbamate In addition, some carbamates are used in human pharmacotherapy, for example, the acetylcholinesterase inhibitors neostigmine and rivastigmine, whose chemical structure is based on the natural alkaloid physostigmine. Other examples are meprobamate and its derivatives like carisoprodol, felbamate, mebutamate, a... | https://en.wikipedia.org/wiki?curid=666459 |
Diazomethane is the chemical compound CHN, discovered by German chemist Hans von Pechmann in 1894. It is the simplest diazo compound. In the pure form at room temperature, it is an extremely sensitive explosive yellow gas; thus, it is almost universally used as a solution in diethyl ether. The compound is a popular met... | https://en.wikipedia.org/wiki?curid=667404 |
Diazomethane is prepared by hydrolysis of an ethereal solution of an "N"-methyl nitrosamide with aqueous base. The traditional precursor is "N"-nitroso-"N"-methylurea, but this compound is itself somewhat unstable, and nowadays compounds such as "N"-methyl-"N"'-nitro-"N"-nitrosoguanidine (MNNG) and "N"-methyl-"N"-nitro... | https://en.wikipedia.org/wiki?curid=667404 |
Diazomethane Like any other alkylating agent it is expected to be carcinogenic, but such concerns are overshadowed by its serious acute toxicity. CHN may explode in contact with sharp edges, such as ground-glass joints, even scratches in glassware. Glassware should be inspected before use and preparation should take pl... | https://en.wikipedia.org/wiki?curid=667404 |
Tonks–Girardeau gas In physics, a is a Bose gas in which the repulsive interactions between bosonic particles confined to one dimension dominate the physics of the system. It is named after physicists Marvin D. Girardeau and Lewi Tonks. Strictly speaking, this is not a Bose–Einstein condensate as it does not demonstrat... | https://en.wikipedia.org/wiki?curid=667451 |
Tonks–Girardeau gas coincides with quantum Nonlinear Schrödinger equation for infinite repulsion, which can be efficiently analyzed by Quantum inverse scattering method. This relation help to study Correlation function (statistical mechanics). The correlation functions can be described by Integrable system. In a simple... | https://en.wikipedia.org/wiki?curid=667451 |
Tonks–Girardeau gas For that, the third axis of the lattice is used. It is set to a lower intensity and shorter time than the other two axes, so that tunneling in this direction stays possible. For increasing intensity of the third lattice, atoms in the same lattice well are more and more tightly trapped, which increas... | https://en.wikipedia.org/wiki?curid=667451 |
Rapid single flux quantum In electronics, rapid single flux quantum (RSFQ) is a digital electronic device that uses superconducting devices, namely Josephson junctions, to process digital signals. In RSFQ logic, information is stored in the form of magnetic flux quanta and transferred in the form of Single Flux Quantum... | https://en.wikipedia.org/wiki?curid=667564 |
Rapid single flux quantum For Nb-based junction technology "I""R" is on the order of 1 mV. | https://en.wikipedia.org/wiki?curid=667564 |
Thermochemical equation A Thermochemical Equation is a balanced stoichiometric chemical equation that includes the enthalpy change, ΔH. In variable form, a thermochemical equation would look like this: Where {A, B, C} are the usual agents of a chemical equation with coefficients and “(±) #” is a positive or negative nu... | https://en.wikipedia.org/wiki?curid=668130 |
Thermochemical equation This matter of ΔH being dependent on physical state and molar concentration means that thermochemical equations must be stoichiometrically correct. If one agent of the equation is changed through multiplication, then all agents must be proportionally changed, including ΔH. (See Manipulating Ther... | https://en.wikipedia.org/wiki?curid=668130 |
Thermochemical equation Since ΔH is a state function and so is not dependent on how the reactants become the products, we can use several steps (in the form of several thermochemical equations) to find the ΔH of the overall reaction. Example: This reaction comes about via two steps (a reaction sequence): We want to add... | https://en.wikipedia.org/wiki?curid=668130 |
Material derivative In continuum mechanics, the material derivative describes the time rate of change of some physical quantity (like heat or momentum) of a material element that is subjected to a space-and-time-dependent macroscopic velocity field. The material derivative can serve as a link between Eulerian and Lagra... | https://en.wikipedia.org/wiki?curid=668449 |
Material derivative Confusingly, sometimes the name "convective derivative" is used for the whole material derivative "D/Dt", instead for only the spatial term u·∇, which is also a redundant nomenclature. In the nonredundant nomenclature the material derivative only equals the convective derivative for absent flows. Th... | https://en.wikipedia.org/wiki?curid=668449 |
Material derivative For example, if formula_6 is chosen, the time derivative becomes equal to the partial time derivative, which agrees with the definition of a partial derivative: a derivative taken with respect to some variable (time in this case) holding other variables constant (space in this case). This makes sens... | https://en.wikipedia.org/wiki?curid=668449 |
Material derivative A temperature sensor attached to the swimmer would show temperature varying with time, simply due to the temperature variation from one end of the pool to the other. The material derivative finally is obtained when the path x("t") is chosen to have a velocity equal to the fluid velocity That is, the... | https://en.wikipedia.org/wiki?curid=668449 |
Material derivative For a vector, the gradient becomes a tensor derivative; for tensor fields we may want to take into account not only translation of the coordinate system due to the fluid movement but also its rotation and stretching. This is achieved by the upper convected time derivative. It may be shown that, in o... | https://en.wikipedia.org/wiki?curid=668449 |
Fire point The fire point of a fuel is the lowest temperature at which the vapour of that fuel will continue to burn for at least 5 seconds after ignition by an open flame of standard dimension. At the flash point, a lower temperature, a substance will ignite briefly, but vapor might not be produced at a rate to sustai... | https://en.wikipedia.org/wiki?curid=668710 |
Oil paint is a type of slow-drying paint that consists of particles of pigment suspended in a drying oil, commonly linseed oil. The viscosity of the paint may be modified by the addition of a solvent such as turpentine or white spirit, and varnish may be added to increase the glossiness of the dried oil paint film. Oil... | https://en.wikipedia.org/wiki?curid=668958 |
Oil paint Well known Dutch-American artist Willem De Kooning is known for saying “Flesh is the reason oil paint was invented”. The oldest known oil paintings date from 650 AD, found in 2008 in caves in Afghanistan's Bamiyan Valley, "using walnut and poppy seed oils." Though the ancient Mediterranean civilizations of Gr... | https://en.wikipedia.org/wiki?curid=668958 |
Oil paint In the 14th century, Cennino Cennini described a painting technique utilizing tempera painting covered by light layers of oil. The slow-drying properties of organic oils were commonly known to early painters. However, the difficulty in acquiring and working the materials meant that they were rarely used (and ... | https://en.wikipedia.org/wiki?curid=668958 |
Oil paint The Flemish-trained or influenced Antonello da Messina, who Vasari wrongly credited with the introduction of oil paint to Italy, does seem to have improved the formula by adding litharge, or lead (II) oxide. The new mixture had a honey-like consistency and better drying properties (drying evenly without crack... | https://en.wikipedia.org/wiki?curid=668958 |
Oil paint ” For the impressionists, tubed paints offered an easily accessible variety of colors for their plein air palettes, motivating them to make spontaneous color choices. With greater quantities of preserved paint, they were able to apply paint more thickly. Traditional oil paints require an oil that always harde... | https://en.wikipedia.org/wiki?curid=668958 |
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