text stringlengths 0 73.6k | source stringclasses 4
values |
|---|---|
Thermal expansion valve-Thermal expansion valve-A thermal expansion valve or thermostatic expansion valve (often abbreviated as TEV, TXV, or TX valve) is a component in vapor-compression refrigeration and air conditioning systems that controls the amount of refrigerant released into the evaporator and is intended to re... | milkshake721/2.1M-wiki-STEM |
Thermal expansion valve-Thermal expansion valve-Thermal expansion valves are often referred to generically as "metering devices", although this may also refer to any other device that releases liquid refrigerant into the low-pressure section but does not react to temperature, such as a capillary tube or a pressure-cont... | milkshake721/2.1M-wiki-STEM |
Thermal expansion valve-Theory of operation-A thermal expansion valve is a key element to a heat pump; this is the cycle that makes air conditioning, or air cooling, possible. A basic refrigeration cycle consists of four major elements: a compressor, a condenser, a metering device and an evaporator. As a refrigerant pa... | milkshake721/2.1M-wiki-STEM |
Thermal expansion valve-Theory of operation-The cycle starts when refrigerant enters the compressor in a low-pressure, moderate-temperature, gaseous form. The refrigerant is compressed by the compressor to a high-pressure and high-temperature gaseous state. The high-pressure and high-temperature gas then enters the con... | milkshake721/2.1M-wiki-STEM |
Thermal expansion valve-Theory of operation-A TXV type expansion device has a sensing bulb that is filled with a liquid whose thermodynamic properties are similar to those of the refrigerant. This bulb is thermally connected to the output of the evaporator so that the temperature of the refrigerant that leaves the evap... | milkshake721/2.1M-wiki-STEM |
Thermal expansion valve-Theory of operation-The superheat is the excess temperature of the vapor above its boiling point at the evaporating pressure. No superheat indicates that the refrigerant is not being fully vaporized within the evaporator and liquid may end up recirculated to the compressor which is inefficient a... | milkshake721/2.1M-wiki-STEM |
Thermal expansion valve-Theory of operation-Some thermal expansion valves are also specifically designed to ensure that a certain minimum flow of refrigerant can always flow through the system, while others can also be designed to control the evaporator's pressure so that it never rises above a maximum value. | milkshake721/2.1M-wiki-STEM |
Thermal expansion valve-Description-Flow control, or metering, of the refrigerant is accomplished by use of a temperature sensing bulb, filled with a gas or liquid charge similar to the one inside the system, that causes the orifice in the valve to open against the spring pressure in the valve body as the temperature o... | milkshake721/2.1M-wiki-STEM |
Thermal expansion valve-Description-At heat loads which are very low compared to the valve's power rating, the orifice can become oversized for the heat load, and the valve can begin to repeatedly open and close, in an attempt to control the superheat to the set value, making the superheat oscillate. Cross charges, tha... | milkshake721/2.1M-wiki-STEM |
Thermal expansion valve-Description-A low refrigerant charge condition is often accompanied when the compressor is operational by a loud whooshing sound heard from the thermal expansion valve and the evaporator, which is caused by the lack of a liquid head right before the valve's moving orifice, resulting in the orifi... | milkshake721/2.1M-wiki-STEM |
Thermal expansion valve-Types-There are two main types of thermal expansion valves: internally or externally equalized. The difference between externally and internally equalized valves is how the evaporator pressure affects the position of the needle. In internally equalized valves, the evaporator pressure against the... | milkshake721/2.1M-wiki-STEM |
Thermal expansion valve-Types-Internally equalized valves can be used on single circuit evaporator coils having low-pressure drop. If a refrigerant distributor is used for multiple parallel evaporators (rather than a valve on each evaporator) then an externally equalized valve must be used. Externally equalized TXVs ca... | milkshake721/2.1M-wiki-STEM |
Thermal expansion valve-Types-Although the bulb/diaphragm type is used in most systems that control the refrigerant superheat, electronic expansion valves are becoming more common in larger systems or systems with multiple evaporators to allow them to be adjusted independently. Although electronic valves can provide gr... | milkshake721/2.1M-wiki-STEM |
Crouton-Crouton-A crouton is a piece of toasted or fried bread, normally cubed and seasoned. Croutons are used to add texture and flavor to salads—notably the Caesar salad— as an accompaniment to soups and stews, or eaten as a snack food. | milkshake721/2.1M-wiki-STEM |
Crouton-Etymology-The word crouton is derived from the French croûton, itself a diminutive of croûte, meaning "crust". Croutons are often seen in the shape of small cubes, but they can be of any size and shape, up to a very large slice. Many people now use crouton for croute, so the usage has changed. Historically, how... | milkshake721/2.1M-wiki-STEM |
Crouton-Preparation-The preparation of croutons is relatively simple. Typically the cubes of bread are lightly coated in oil or butter (which may be seasoned or flavored for variety) and then baked. Croutons can also be cut into sticks. Some commercial preparations use machinery to sprinkle various seasonings on them. ... | milkshake721/2.1M-wiki-STEM |
Crouton-List of possible ingredients-bread garlic butter or oil (e.g., olive oil or rapeseed oil) Parmesan herbs spices (ground or whole) | milkshake721/2.1M-wiki-STEM |
Crouton-Gastronomy-A dish prepared à la Grenobloise (in the Grenoble manner) has a garnish of small croutons along with beurre noisette, capers, parsley, and lemon.
Dried and cubed bread is commonly sold in large bags in North America to make Thanksgiving holiday stuffing or dressing. However, these are generally diffe... | milkshake721/2.1M-wiki-STEM |
Independent hardware vendor-Independent hardware vendor-An independent hardware vendor (IHV) is a company specializing in making or selling computer hardware, usually for niche markets. | milkshake721/2.1M-wiki-STEM |
Sulforhodamine B-Sulforhodamine B-Sulforhodamine B or Kiton Red 620 (C27H30N2O7S2) is a fluorescent dye with uses spanning from laser-induced fluorescence (LIF) to the quantification of cellular proteins of cultured cells. This red solid dye is very water-soluble. | milkshake721/2.1M-wiki-STEM |
Sulforhodamine B-Spectroscopy-The dye has maximal absorbance at 565 nm light and maximal fluorescence emission at 586 nm light. It does not exhibit pH-dependent absorption or fluorescence over the range of 3 to 10. | milkshake721/2.1M-wiki-STEM |
Sulforhodamine B-Applications-Sulforhodamine B is often used as a membrane-impermeable polar tracer or used for cell density determination via determination of cellular proteins (cytotoxicity assay). | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-X-ray photoelectron spectroscopy-X-ray photoelectron spectroscopy (XPS) is a surface-sensitive quantitative spectroscopic technique based on the photoelectric effect that can identify the elements that exist within a material (elemental composition) or are covering its surface, as well ... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-X-ray photoelectron spectroscopy-XPS belongs to the family of photoemission spectroscopies in which electron population spectra are obtained by irradiating a material with a beam of X-rays. Chemical states are inferred from the measurement of the kinetic energy and the number of the eje... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-X-ray photoelectron spectroscopy-When laboratory X-ray sources are used, XPS easily detects all elements except hydrogen and helium. The detection limit is in the parts per thousand range, but parts per million (ppm) are achievable with long collection times and concentration at top sur... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-X-ray photoelectron spectroscopy-XPS is routinely used to analyze inorganic compounds, metal alloys, polymers, elements, catalysts, glasses, ceramics, paints, papers, inks, woods, plant parts, make-up, teeth, bones, medical implants, bio-materials, coatings,viscous oils, glues, ion-modi... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Basic physics-Because the energy of an X-ray with particular wavelength is known (for Al Kα X-rays, Ephoton = 1486.7 eV), and because the emitted electrons' kinetic energies are measured, the electron binding energy of each of the emitted electrons can be determined by using the photoel... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-History-In 1887, Heinrich Rudolf Hertz discovered but could not explain the photoelectric effect, which was later explained in 1905 by Albert Einstein (Nobel Prize in Physics 1921). Two years after Einstein's publication, in 1907, P.D. Innes experimented with a Röntgen tube, Helmholtz c... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Measurement-A typical XPS spectrum is a plot of the number of electrons detected at a specific binding energy. Each element produces a set of characteristic XPS peaks. These peaks correspond to the electron configuration of the electrons within the atoms, e.g., 1s, 2s, 2p, 3s, etc. The ... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Measurement-Quantitative accuracy and precision XPS is widely used to generate an empirical formula because it readily yields excellent quantitative accuracy from homogeneous solid-state materials. Absolute quantification requires the use of certified (or independently verified) standar... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Measurement-Detection limits Detection limits may vary greatly with the cross section of the core state of interest and the background signal level. In general, photoelectron cross sections increase with atomic number. The background increases with the atomic number of the matrix consti... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Measurement-Degradation during analysis Degradation depends on the sensitivity of the material to the wavelength of X-rays used, the total dose of the X-rays, the temperature of the surface and the level of the vacuum. Metals, alloys, ceramics and most glasses are not measurably degrade... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Measurement-Measured area Measured area depends on instrument design. The minimum analysis area ranges from 10 to 200 micrometres. Largest size for a monochromatic beam of X-rays is 1–5 mm. Non-monochromatic beams are 10–50 mm in diameter. Spectroscopic image resolution levels of 200 nm... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Measurement-Analysis time Typically ranging 1–20 minutes for a broad survey scan that measures the amount of all detectable elements, typically 1–15 minutes for high resolution scan that reveal chemical state differences (for a high signal/noise ratio for count area result often require... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Surface sensitivity-XPS detects only electrons that have actually escaped from the sample into the vacuum of the instrument. In order to escape from the sample, a photoelectron must travel through the sample. Photo-emitted electrons can undergo inelastic collisions, recombination, excit... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Chemical states and chemical shift-The ability to produce chemical state information, i.e. the local bonding environment of an atomic species in question from the topmost few nanometers of the sample makes XPS a unique and valuable tool for understanding the chemistry of the surface. Th... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Instrumentation-The main components of an XPS system are the source of X-rays, an ultra-high vacuum (UHV) chamber with mu-metal magnetic shielding, an electron collection lens, an electron energy analyzer, an electron detector system, a sample introduction chamber, sample mounts, a samp... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Instrumentation-The most prevalent electron spectrometer for XPS is the hemispherical electron analyzer. They have high energy resolution and spatial selection of the emitted electrons. Sometimes, however, much simpler electron energy filters - the cylindrical mirror analyzers are used,... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Instrumentation-Electrons are detected using electron multipliers: a single channeltron for single energy detection, or arrays of channeltrons and microchannel plates for parallel acquisition. These devices consists of a glass channel with a resistive coating on the inside. A high volta... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Instrumentation-Laboratory based XPS In laboratory systems, either 10–30 mm beam diameter non-monochromatic Al Kα or Mg Kα anode radiation is used, or a focused 20-500 micrometer diameter beam single wavelength Al Kα monochromatised radiation. Monochromatic Al Kα X-rays are normally pro... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Instrumentation-Synchrotron based XPS A breakthrough has been brought about in the last decades by the development of large scale synchrotron radiation facilities. Here, bunches of relativistic electrons kept in orbit inside a storage ring are accelerated through bending magnets or inse... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Data processing-Peak identification The number of peaks produced by a single element varies from 1 to more than 20. Tables of binding energies that identify the shell and spin-orbit of each peak produced by a given element are included with modern XPS instruments, and can be found in va... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Data processing-Before beginning the process of peak identification, the analyst must determine if the binding energies of the unprocessed survey spectrum (0-1400 eV) have or have not been shifted due to a positive or negative surface charge. This is most often done by looking for two p... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Data processing-Charge referencing insulators Charge referencing is needed when a sample suffers a charge induced shift of experimental binding energies to obtain meaningful binding energies from both wide-scan, high sensitivity (low energy resolution) survey spectra (0-1100 eV), and al... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Data processing-Charge referencing is performed by adding a Charge Correction Factor to each of the experimentally measured peaks. Since various hydrocarbon species appear on all air-exposed surfaces, the binding energy of the hydrocarbon C (1s) XPS peak is used to charge correct all en... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Data processing-Conductive materials and most native oxides of conductors should never need charge referencing. Conductive materials should never be charge referenced unless the topmost layer of the sample has a thick non-conductive film. The charging effect, if needed, can also be comp... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Data processing-Peak-fitting The process of peak-fitting high energy resolution XPS spectra is a mixture of scientific knowledge and experience. The process is affected by instrument design, instrument components, experimental settings and sample variables. Before starting any peak-fit ... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Data processing-Peak shapes depend on instrument parameters, experimental parameters and sample characteristics.
Instrument design factors include linewidth and purity of X-rays used (monochromatic Al, non-monochromatic Mg, Synchrotron, Ag, Zr), as well as properties of the electron ana... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Theoretical aspects-Quantum mechanical treatment When a photoemission event takes place, the following energy conservation rule holds: hν=|Ebv|+Ekin where hν is the photon energy, |Ebv| is the electron BE (binding energy with respect to the vacuum level) prior to ionization, and Ekin... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Theoretical aspects-The one—particle Hamiltonian for an electron subjected to an electromagnetic field is given by: iℏ∂ψ∂t=[12m(p^−ecA^)2+V^]ψ=H^ψ ,where ψ is the electron wave function, A is the vector potential of the electromagnetic field and V is the unperturbed potential of the ... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Theoretical aspects-In first-order perturbation approach, the one-electron Hamiltonian can be split into two terms, an unperturbed Hamiltonian H^0 , plus an interaction Hamiltonian H^′ , which describes the effects of the electromagnetic field: H^′=−emcA^⋅p^ In time-dependent perturba... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Theoretical aspects-Assuming an exponential decay probability for the core hole in the time domain ( exp −t/τ ), the spectral function will have a Lorentzian shape, with a FWHM (Full Width at Half Maximum) Γ given by: IL(E)=I0πΓ/2(E−Eb)2+(Γ/2)2 From the theory of Fourier transforms, ... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Theoretical aspects-Besides Lorentzian broadening, photoemission spectra are also affected by a Gaussian broadening, whose contribution can be expressed by exp (−(E−Eb)22σ2) Three main factors enter the Gaussian broadening of the spectra: the experimental energy resolution, vibrational... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Theoretical aspects-The first effect is caused by the non perfect monochromaticity of the photon beam -which results in a finite bandwidth- and by the limited resolving power of the analyzer. The vibrational component is produced by the excitation of low energy vibrational modes both in... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Theoretical aspects-Theory of core level photoemission of electrons Inelastic mean free path In a solid, inelastic scattering events also contribute to the photoemission process, generating electron-hole pairs which show up as an inelastic tail on the high BE side of the main photoemiss... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Theoretical aspects-Plasmonic effects In some cases, energy loss features due to plasmon excitations are also observed. This can either be a final state effect caused by core hole decay, which generates quantized electron wave excitations in the solid (intrinsic plasmons), or it can be ... | milkshake721/2.1M-wiki-STEM |
X-ray photoelectron spectroscopy-Theoretical aspects-Vibrational effects Temperature-dependent atomic lattice vibrations, or phonons, can broaden the core level components and attenuate the interference patterns in an X-ray photoelectron diffraction (XPD) experiment. The simplest way to account for vibrational effects ... | milkshake721/2.1M-wiki-STEM |
LZ77 and LZ78-LZ77 and LZ78-LZ77 and LZ78 are the two lossless data compression algorithms published in papers by Abraham Lempel and Jacob Ziv in 1977 and 1978.
They are also known as LZ1 and LZ2 respectively. These two algorithms form the basis for many variations including LZW, LZSS, LZMA and others. Besides their ac... | milkshake721/2.1M-wiki-STEM |
LZ77 and LZ78-LZ77 and LZ78-Since LZ77 encodes and decodes from a sliding window over previously seen characters, decompression must always start at the beginning of the input. Conceptually, LZ78 decompression could allow random access to the input if the entire dictionary were known in advance. However, in practice th... | milkshake721/2.1M-wiki-STEM |
LZ77 and LZ78-Theoretical efficiency-In the second of the two papers that introduced these algorithms they are analyzed as encoders defined by finite-state machines. A measure analogous to information entropy is developed for individual sequences (as opposed to probabilistic ensembles). This measure gives a bound on th... | milkshake721/2.1M-wiki-STEM |
LZ77 and LZ78-LZ77-LZ77 algorithms achieve compression by replacing repeated occurrences of data with references to a single copy of that data existing earlier in the uncompressed data stream. A match is encoded by a pair of numbers called a length-distance pair, which is equivalent to the statement "each of the next l... | milkshake721/2.1M-wiki-STEM |
LZ77 and LZ78-LZ77-It is not only acceptable but frequently useful to allow length-distance pairs to specify a length that actually exceeds the distance. As a copy command, this is puzzling: "Go back four characters and copy ten characters from that position into the current position". How can ten characters be copied ... | milkshake721/2.1M-wiki-STEM |
LZ77 and LZ78-LZ77-Another way to see things is as follows: While encoding, for the search pointer to continue finding matched pairs past the end of the search window, all characters from the first match at offset D and forward to the end of the search window must have matched input, and these are the (previously seen)... | milkshake721/2.1M-wiki-STEM |
LZ77 and LZ78-LZ77-Upon decoding [D, L, c], again, D = LR. When the first LR characters are read to the output, this corresponds to a single run unit appended to the output buffer. At this point, the read pointer could be thought of as only needing to return int(L/LR) + (1 if L mod LR ≠ 0) times to the start of that si... | milkshake721/2.1M-wiki-STEM |
LZ77 and LZ78-LZ77-Considering the above, especially if the compression of data runs is expected to predominate, the window search should begin at the end of the window and proceed backwards, since run patterns, if they exist, will be found first and allow the search to terminate, absolutely if the current maximal matc... | milkshake721/2.1M-wiki-STEM |
LZ77 and LZ78-LZ77-Pseudocode The pseudocode is a reproduction of the LZ77 compression algorithm sliding window. | milkshake721/2.1M-wiki-STEM |
LZ77 and LZ78-LZ77-while input is not empty do match := longest repeated occurrence of input that begins in window if match exists then d := distance to start of match l := length of match c := char following match in input else d := 0 l := 0 c := first char of input end if output (d, l, c) discard l + 1 chars from fro... | milkshake721/2.1M-wiki-STEM |
LZ77 and LZ78-LZ77-LZSS improves on LZ77 by using a 1-bit flag to indicate whether the next chunk of data is a literal or a length–distance pair, and using literals if a length–distance pair would be longer. | milkshake721/2.1M-wiki-STEM |
LZ77 and LZ78-LZ77-In the PalmDoc format, a length–distance pair is always encoded by a two-byte sequence. Of the 16 bits that make up these two bytes, 11 bits go to encoding the distance, 3 go to encoding the length, and the remaining two are used to make sure the decoder can identify the first byte as the beginning o... | milkshake721/2.1M-wiki-STEM |
LZ77 and LZ78-LZ77-In the implementation used for many games by Electronic Arts, the size in bytes of a length–distance pair can be specified inside the first byte of the length–distance pair itself; depending on whether the first byte begins with a 0, 10, 110, or 111 (when read in big-endian bit orientation), the leng... | milkshake721/2.1M-wiki-STEM |
LZ77 and LZ78-LZ77-As of 2008, the most popular LZ77-based compression method is DEFLATE; it combines LZSS with Huffman coding. Literals, lengths, and a symbol to indicate the end of the current block of data are all placed together into one alphabet. Distances can be safely placed into a separate alphabet; because a d... | milkshake721/2.1M-wiki-STEM |
LZ77 and LZ78-LZ78-The LZ78 algorithms compress sequential data by building a dictionary of token sequences from the input, and then replacing the second and subsequent occurrence of the sequence in the data stream with a reference to the dictionary entry. The observation is that the number of repeated sequences is a g... | milkshake721/2.1M-wiki-STEM |
LZ77 and LZ78-LZW-LZW is an LZ78-based algorithm that uses a dictionary pre-initialized with all possible characters (symbols) or emulation of a pre-initialized dictionary. The main improvement of LZW is that when a match is not found, the current input stream character is assumed to be the first character of an existi... | milkshake721/2.1M-wiki-STEM |
LZ77 and LZ78-LZW-BTLZ is an LZ78-based algorithm that was developed for use in real-time communications systems (originally modems) and standardized by CCITT/ITU as V.42bis. When the trie-structured dictionary is full, a simple re-use/recovery algorithm is used to ensure that the dictionary can keep adapting to changi... | milkshake721/2.1M-wiki-STEM |
Voiced epiglottal tap-Voiced epiglottal tap-The voiced epiglottal or pharyngeal tap or flap is not known to exist as a phoneme in any language. However, it exists as the intervocalic voiced allophone of the otherwise voiceless epiglottal stop /ʡ/ of Dahalo and perhaps of other languages. | milkshake721/2.1M-wiki-STEM |
Voiced epiglottal tap-Voiced epiglottal tap-It may also exist in Iraqi Arabic, where the consonant 'ayn is too short to be an epiglottal stop, but has too much of a burst to be a fricative or approximant.There is no dedicated symbol for this sound in the IPA, but it can be transcribed by adding an "extra short" diacrit... | milkshake721/2.1M-wiki-STEM |
Voiced epiglottal tap-Features-Its manner of articulation is tap or flap, which means it is produced with a single contraction of the muscles so that one articulator (usually the tongue) is thrown against another.
Its place of articulation is epiglottal, which means it is articulated with the aryepiglottic folds agains... | milkshake721/2.1M-wiki-STEM |
Entropy (energy dispersal)-Entropy (energy dispersal)-In thermodynamics, the interpretation of entropy as a measure of energy dispersal has been exercised against the background of the traditional view, introduced by Ludwig Boltzmann, of entropy as a quantitative measure of disorder. The energy dispersal approach avoid... | milkshake721/2.1M-wiki-STEM |
Entropy (energy dispersal)-Entropy (energy dispersal)-Some educators propose that the energy dispersal idea is easier to understand than the traditional approach. The concept has been used to facilitate teaching entropy to students beginning university chemistry and biology. | milkshake721/2.1M-wiki-STEM |
Entropy (energy dispersal)-Comparisons with traditional approach-The term "entropy" has been in use from early in the history of classical thermodynamics, and with the development of statistical thermodynamics and quantum theory, entropy changes have been described in terms of the mixing or "spreading" of the total ene... | milkshake721/2.1M-wiki-STEM |
Entropy (energy dispersal)-Comparisons with traditional approach-Such descriptions have tended to be used together with commonly used terms such as disorder and randomness, which are ambiguous, and whose everyday meaning is the opposite of what they are intended to mean in thermodynamics. Not only does this situation c... | milkshake721/2.1M-wiki-STEM |
Entropy (energy dispersal)-Description-Increase of entropy in a thermodynamic process can be described in terms of "energy dispersal" and the "spreading of energy," while avoiding mention of "disorder" except when explaining misconceptions. All explanations of where and how energy is dispersing or spreading have been r... | milkshake721/2.1M-wiki-STEM |
Entropy (energy dispersal)-Description-The statistical interpretation is related to quantum mechanics in describing the way that energy is distributed (quantized) amongst molecules on specific energy levels, with all the energy of the macrostate always in only one microstate at one instant. Entropy is described as meas... | milkshake721/2.1M-wiki-STEM |
Entropy (energy dispersal)-Current adoption-Variants of the energy dispersal approach have been adopted in number of undergraduate chemistry texts, mainly in the United States. One respected text states: The concept of the number of microstates makes quantitative the ill-defined qualitative concepts of 'disorder' and t... | milkshake721/2.1M-wiki-STEM |
Entropy (energy dispersal)-History-The concept of 'dissipation of energy' was used in Lord Kelvin's 1852 article "On a Universal Tendency in Nature to the Dissipation of Mechanical Energy." He distinguished between two types or "stores" of mechanical energy: "statical" and "dynamical." He discussed how these two types ... | milkshake721/2.1M-wiki-STEM |
Torpex Games-Torpex Games-Torpex Games was a game development studio located in Bellevue, Washington, United States.
The studio was notable because their video game Schizoid was the first Xbox Live Arcade title to utilize the Microsoft framework, XNA Game Studio Express.Torpex Games was founded by industry veterans Bil... | milkshake721/2.1M-wiki-STEM |
Torpex Games-Games-Schizoid (2008) Bejeweled Blitz LIVE (2011) | milkshake721/2.1M-wiki-STEM |
Compound of five small cubicuboctahedra-Compound of five small cubicuboctahedra-This uniform polyhedron compound is a composition of 5 small cubicuboctahedra, in the same vertex arrangement as the compound of 5 small rhombicuboctahedra. | milkshake721/2.1M-wiki-STEM |
Low-head hydro power-Low-head hydro power-Low-head hydropower refers to the development of hydroelectric power where the head is typically less than 20 metres, although precise definitions vary. Head is the vertical height measured between the hydro intake water level and the water level at the point of discharge. Usin... | milkshake721/2.1M-wiki-STEM |
Low-head hydro power-Comparison to conventional hydro-Most current hydroelectric projects use a large hydraulic head to power turbines to generate electricity. The hydraulic head either occurs naturally, such as a waterfall, or is created by constructing a dam in a river valley, creating a reservoir. Using a controlled... | milkshake721/2.1M-wiki-STEM |
Low-head hydro power-Comparison to conventional hydro-Within low-head hydropower there are several of standard situations: Run-of-the-river: Low-head small hydropower can be produced from rivers, often described as run-of-river or run-of-the-river projects. Suitable locations include weirs, streams, locks, rivers and w... | milkshake721/2.1M-wiki-STEM |
Low-head hydro power-Comparison to conventional hydro-Tidal power: In combination with a lagoon or barrage the tides can be used to create a head difference. The largest tidal range is at the Bay of Fundy, between the Canadian provinces of New Brunswick and Nova Scotia, Canada which can reach 13.6m. The first tidal ran... | milkshake721/2.1M-wiki-STEM |
Low-head hydro power-Types of low-head turbines-Turbines suitable for use in very-low-head applications are different from the Francis, propeller, Kaplan, or Pelton types used in more conventional large hydro. Different types of low-head turbines are: Venturi-enhanced turbine: This type of turbine uses venturi principl... | milkshake721/2.1M-wiki-STEM |
Low-head hydro power-Types of low-head turbines-Archimedes screw: Water is fed into the top of the screw forcing it to rotate. The rotating shaft can then be used to drive an electric generator. A gear box is required, since the rotational speed is very low. The screw is used at low heads (1.5–5 metres) and medium to h... | milkshake721/2.1M-wiki-STEM |
Low-head hydro power-Types of low-head turbines-Kaplan turbine: This turbine is a propeller-type turbine which has adjustable blades to achieve efficiency over a wide range of heads and flows. The Kaplan can be used at low to medium heads (1.5–20 metres) and medium to high flows (3 m3/s–30 m3/s). For higher flows multi... | milkshake721/2.1M-wiki-STEM |
Low-head hydro power-Types of low-head turbines-Cross-flow turbine: Also known as Banki-Mitchell or Ossberger turbines, these devices are used for a large range of hydraulic heads (from 2 to 100 meters) and flow rates (from 0.03 to 20 m3/s), but are more efficient for low heads and low power outputs. They are considere... | milkshake721/2.1M-wiki-STEM |
Low-head hydro power-Types of low-head turbines-Water wheel: Water wheels can be used at low heads (1–5 metres) and medium flows (0.3–1.5 m3/s) and are considered safe for aquatic life.
Gravitation water vortex power plant: This type of hydro power plant use the power of a gravitation water vortex, which only exists at... | milkshake721/2.1M-wiki-STEM |
Low-head hydro power-Environmental impact of low-head hydropower-A number of concerns have been raised about the environmental impacts of river current and tidal devices. Among the most important of these are: Aquatic life. Concerns have been raised about the danger of rotating blades to aquatic life, such as seals and... | milkshake721/2.1M-wiki-STEM |
Low-head hydro power-Environmental impact of low-head hydropower-Bathymetry. By altering wave patterns and tidal streams, devices will undoubtedly have an effect, for example, on the deposition of sediment. Research carried out to date would seem to indicate that the effects would not be significant, and may even be po... | milkshake721/2.1M-wiki-STEM |
Low-head hydro power-Environmental impact of low-head hydropower-Landscape. In rivers or similar watercourses, sensitive environmental parameters can make planning permissions for hydropower installations difficult. Large infrastructure, and above water visible infrastructure such as Archimedes Screw systems and turbin... | milkshake721/2.1M-wiki-STEM |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.