text stringlengths 0 73.6k | source stringclasses 4
values |
|---|---|
Protective distribution system-Simple distribution-Simple distribution PDSs are afforded a reduced level of physical security protection as compared to a hardened distribution PDS. They use a simple carrier system and the following means are acceptable under NSTISSI 7003: The data cables should be installed in a carri... | milkshake721/2.1M-wiki-STEM |
Fibroblast growth factor 8-Fibroblast growth factor 8-Fibroblast growth factor 8 (FGF-8) is a protein that in humans is encoded by the FGF8 gene. | milkshake721/2.1M-wiki-STEM |
Fibroblast growth factor 8-Function-The protein encoded by this gene is a member of the fibroblast growth factor (FGF) family. FGF family members possess broad mitogenic and cell survival activities, and are involved in a variety of biological processes, including embryonic development, cell growth, morphogenesis, tiss... | milkshake721/2.1M-wiki-STEM |
Fibroblast growth factor 8-Function-FGF8 signaling from the apical ectodermal ridge (AER), which borders the distal end of the limb bud, is necessary for forming normal limbs. In the absence of FGF8, limb buds can be reduced in size, hypoplasia or aplasia of bones or digits within the three limb segments may occur, as ... | milkshake721/2.1M-wiki-STEM |
Fibroblast growth factor 8-Clinical significance-This protein is known to be a factor that supports androgen and anchorage independent growth of mammary tumor cells. Overexpression of this gene has been shown to increase tumor growth and angiogenesis. The adult expression of this gene was once thought to be restricted ... | milkshake721/2.1M-wiki-STEM |
Poularde-Poularde-Poularde is culinary term for a chicken that is at least 120 days old at the time of slaughter and fattened with a rich diet that delays egg production. In the past it was common to spay the chickens early in life to ensure desirable meat quality, similar to the castration of a capon. | milkshake721/2.1M-wiki-STEM |
Poularde-Poularde-Similar terms are often confused: in English, pullet refers to a young hen, generally under one year old. Sometimes it is more specific, indicating a hen that is fully grown but has not reached ‘point-of-lay’, i.e. has not yet started laying eggs, which often happens between 16 and 24 weeks of age, de... | milkshake721/2.1M-wiki-STEM |
Poularde-Poularde-Examples of protected certifications outside France include the Poularde de Bruxelles from Belgium, the Steierische Poularde from Austria, and the Poularde Den Dungen from the Netherlands. | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cell-A dye-sensitized solar cell (DSSC, DSC, DYSC or Grätzel cell) is a low-cost solar cell belonging to the group of thin film solar cells. It is based on a semiconductor formed between a photo-sensitized anode and an electrolyte, a photoelectrochemical system. The modern... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Current technology: semiconductor solar cells-In a traditional solid-state semiconductor, a solar cell is made from two doped crystals, one doped with n-type impurities (n-type semiconductor), which add additional free conduction band electrons, and the other doped with p-type impurities (p-ty... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Current technology: semiconductor solar cells-By far the biggest problem with the conventional approach is cost; solar cells require a relatively thick layer of doped silicon in order to have reasonable photon capture rates, and silicon processing is expensive. There have been a number of diff... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-In the late 1960s it was discovered that illuminated organic dyes can generate electricity at oxide electrodes in electrochemical cells. In an effort to understand and simulate the primary processes in photosynthesis the phenomenon was studied at the University of Ca... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-The working principle for n-type DSSCs can be summarized into a few basic steps. Sunlight passes through the transparent electrode into the dye layer where it can excite electrons that then flow into the conduction band of the n-type semiconductor, typically titanium... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-The basic working principle above, is similar in a p-type DSSC, where the dye-sensitised semiconductor is of p-type nature (typically nickel oxide). However, instead of injecting an electron into the semiconductor, in a p-type DSSC, a hole flows from the dye into the... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-The dye molecules are quite small (nanometer sized), so in order to capture a reasonable amount of the incoming light the layer of dye molecules needs to be made fairly thick, much thicker than the molecules themselves. To address this problem, a nanomaterial is used... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-Counter Electrode Materials One of the most important components of DSSC is the counter electrode. As stated before, the counter electrode is responsible for collecting electrons from the external circuit and introducing them back into the electrolyte to catalyze the... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-Morphology Even with the same composition, morphology of the nanoparticles that make up the counter electrode play such an integral role in determining the efficiency of the overall photovoltaic. Because a material's electrocatalytic potential is highly dependent on ... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-In 2017, Huang et al. utilized various surfactants in a microemulsion-assisted hydrothermal synthesis of CoSe2/CoSeO3 composite crystals to produce nanocubes, nanorods, and nanoparticles. Comparison of these three morphologies revealed that the hybrid composite nanop... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-With a similar study but a different system, Du et al. in 2017 determined that the ternary oxide of NiCo2O4 had the greatest power conversion efficiency and electrocatalytic ability as nanoflowers when compared to nanorods or nanosheets. Du et al. realized that explo... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-Stoichiometry Of course, the composition of the material that is used as the counter electrode is extremely important to creating a working photovoltaic, as the valence and conduction energy bands must overlap with those of the redox electrolyte species to allow for ... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-In 2018, Jin et al. prepared ternary nickel cobalt selenide (NixCoySe) films at various stoichiometric ratios of nickel and cobalt to understand its impact on the resulting cell performance. Nickel and cobalt bimetallic alloys were known to have outstanding electron ... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-Synergy One last area that has been actively studied is the synergy of different materials in promoting superior electroactive performance. Whether through various charge transport material, electrochemical species, or morphologies, exploiting the synergetic relation... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-In 2016, Lu et al. mixed nickel cobalt sulfide microparticles with reduced graphene oxide (rGO) nanoflakes to create the counter electrode. Lu et al. discovered not only that the rGO acted as a co-catalyst in accelerating the triiodide reduction, but also that the mi... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-Construction In the case of the original Grätzel and O'Regan design, the cell has 3 primary parts. On top is a transparent anode made of fluoride-doped tin dioxide (SnO2:F) deposited on the back of a (typically glass) plate. On the back of this conductive plate is a ... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-A separate plate is then made with a thin layer of the iodide electrolyte spread over a conductive sheet, typically platinum metal. The two plates are then joined and sealed together to prevent the electrolyte from leaking. The construction is simple enough that ther... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-One of the efficient DSSCs devices uses ruthenium-based molecular dye, e.g. [Ru(4,4'-dicarboxy-2,2'-bipyridine)2(NCS)2] (N3), that is bound to a photoanode via carboxylate moieties. The photoanode consists of 12 μm thick film of transparent 10–20 nm diameter TiO2 nan... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-Mechanism of DSSCs The following steps convert in a conventional n-type DSSC photons (light) to current: The efficiency of a DSSC depends on four energy levels of the component: the excited state (approximately LUMO) and the ground state (HOMO) of the photosensitizer... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-Nanoplant-like morphology In DSSC, electrodes consisted of sintered semiconducting nanoparticles, mainly TiO2 or ZnO. These nanoparticle DSSCs rely on trap-limited diffusion through the semiconductor nanoparticles for the electron transport. This limits the device ef... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-Operation In a conventional n-type DSSC, sunlight enters the cell through the transparent SnO2:F top contact, striking the dye on the surface of the TiO2. Photons striking the dye with enough energy to be absorbed create an excited state of the dye, from which an ele... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-Meanwhile, the dye molecule has lost an electron and the molecule will decompose if another electron is not provided. The dye strips one from iodide in electrolyte below the TiO2, oxidizing it into triiodide. This reaction occurs quite quickly compared to the time th... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-The triiodide then recovers its missing electron by mechanically diffusing to the bottom of the cell, where the counter electrode re-introduces the electrons after flowing through the external circuit. | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-Efficiency Several important measures are used to characterize solar cells. The most obvious is the total amount of electrical power produced for a given amount of solar power shining on the cell. Expressed as a percentage, this is known as the solar conversion effic... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-In quantum efficiency terms, DSSCs are extremely efficient. Due to their "depth" in the nanostructure there is a very high chance that a photon will be absorbed, and the dyes are very effective at converting them to electrons. Most of the small losses that do exist i... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-In theory, the maximum voltage generated by such a cell is simply the difference between the (quasi-)Fermi level of the TiO2 and the redox potential of the electrolyte, about 0.7 V under solar illumination conditions (Voc). That is, if an illuminated DSSC is connecte... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-Although the dye is highly efficient at converting absorbed photons into free electrons in the TiO2, only photons absorbed by the dye ultimately produce current. The rate of photon absorption depends upon the absorption spectrum of the sensitized TiO2 layer and upon ... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-Overall peak power conversion efficiency for current DSSCs is about 11%. Current record for prototypes lies at 15%. | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-Degradation DSSCs degrade when exposed to light. In 2014 air infiltration of the commonly-used amorphous Spiro-MeOTAD hole-transport layer was identified as the primary cause of the degradation, rather than oxidation. The damage could be avoided by the addition of an... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-Advantages DSSCs are currently the most efficient third-generation (2005 Basic Research Solar Energy Utilization 16) solar technology available. Other thin-film technologies are typically between 5% and 13%, and traditional low-cost commercial silicon panels operate ... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-There is another area where DSSCs are particularly attractive. The process of injecting an electron directly into the TiO2 is qualitatively different from that occurring in a traditional cell, where the electron is "promoted" within the original crystal. In theory, g... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-In comparison, the injection process used in the DSSC does not introduce a hole in the TiO2, only an extra electron. Although it is energetically possible for the electron to recombine back into the dye, the rate at which this occurs is quite slow compared to the rat... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-As a result of these favorable "differential kinetics", DSSCs work even in low-light conditions. DSSCs are therefore able to work under cloudy skies and non-direct sunlight, whereas traditional designs would suffer a "cutout" at some lower limit of illumination, when... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-Disadvantages The major disadvantage to the DSSC design is the use of the liquid electrolyte, which has temperature stability problems. At low temperatures the electrolyte can freeze, halting power production and potentially leading to physical damage. Higher tempera... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-Photocathodes and tandem cells Dye sensitised solar cells operate as a photoanode (n-DSC), where photocurrent result from electron injection by the sensitized dye. Photocathodes (p-DSCs) operate in an inverse mode compared to the conventional n-DSC, where dye-excitat... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-A standard tandem cell consists of one n-DSC and one p-DSC in a simple sandwich configuration with an intermediate electrolyte layer. n-DSC and p-DSC are connected in series, which implies that the resulting photocurrent will be controlled by the weakest photoelectro... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Dye-sensitized solar cells-Researchers have found that using dyes comprising a perylenemonoimide (PMI) as the acceptor and an oligothiophene coupled to triphenylamine as the donor greatly improve the performance of p-DSC by reducing charge recombination rate following dye-sensitized hole injec... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Development-The dyes used in early experimental cells (circa 1995) were sensitive only in the high-frequency end of the solar spectrum, in the UV and blue. Newer versions were quickly introduced (circa 1999) that had much wider frequency response, notably "triscarboxy-ruthenium terpyridine" [R... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Development-A solar cell must be capable of producing electricity for at least twenty years, without a significant decrease in efficiency (life span). The "black dye" system was subjected to 50 million cycles, the equivalent of ten years' exposure to the sun in Switzerland. No discernible perf... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Development-DSSCs are still at the start of their development cycle. Efficiency gains are possible and have recently started more widespread study. These include the use of quantum dots for conversion of higher-energy (higher frequency) light into multiple electrons, using solid-state electrol... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Development-New developments 2003 A group of researchers at the École Polytechnique Fédérale de Lausanne (EPFL) has reportedly increased the thermostability of DSC by using amphiphilic ruthenium sensitizer in conjunction with quasi-solid-state gel electrolyte. The stability of the device match... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Development-The use of the amphiphilic Z-907 dye in conjunction with the polymer gel electrolyte in DSC achieved an energy conversion efficiency of 6.1%. More importantly, the device was stable under thermal stress and soaking with light. The high conversion efficiency of the cell was sustaine... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Development-The enhanced performance may arise from a decrease in solvent permeation across the sealant due to the application of the polymer gel electrolyte. The polymer gel electrolyte is quasi-solid at room temperature, and becomes a viscous liquid (viscosity: 4.34 mPa·s) at 80 °C compared ... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Development-2006 The first successful solid-hybrid dye-sensitized solar cells were reported.To improve electron transport in these solar cells, while maintaining the high surface area needed for dye adsorption, two researchers have designed alternate semiconductor morphologies, such as arrays ... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Development-2007 Wayne Campbell at Massey University, New Zealand, has experimented with a wide variety of organic dyes based on porphyrin. In nature, porphyrin is the basic building block of the hemoproteins, which include chlorophyll in plants and hemoglobin in animals. He reports efficiency... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Development-2008 An article published in Nature Materials demonstrated cell efficiencies of 8.2% using a new solvent-free liquid redox electrolyte consisting of a melt of three salts, as an alternative to using organic solvents as an electrolyte solution. Although the efficiency with this elec... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Development-2009 A group of researchers at Georgia Tech made dye-sensitized solar cells with a higher effective surface area by wrapping the cells around a quartz optical fiber. The researchers removed the cladding from optical fibers, grew zinc oxide nanowires along the surface, treated them ... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Development-2010 Researchers at the École Polytechnique Fédérale de Lausanne and at the Université du Québec à Montréal claim to have overcome two of the DSC's major issues: "New molecules" have been created for the electrolyte, resulting in a liquid or gel that is transparent and non-corrosiv... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Development-Dyesol is extremely encouraged by the breakthroughs in the chemistry allowing the production of the target molecules. This creates a path to the immediate commercial utilisation of these new materials."Dyesol and Tata Steel Europe announced in November the targeted development of G... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Development-2012 Northwestern University researchers announced a solution to a primary problem of DSSCs, that of difficulties in using and containing the liquid electrolyte and the consequent relatively short useful life of the device. This is achieved through the use of nanotechnology and the... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Development-2013 During the last 5–10 years, a new kind of DSSC has been developed – the solid state dye-sensitized solar cell. In this case the liquid electrolyte is replaced by one of several solid hole conducting materials. From 2009 to 2013 the efficiency of Solid State DSSCs has dramatica... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Development-2018 Researchers have investigated the role of surface plasmon resonances present on gold nanorods in the performance of dye-sensitized solar cells. They found that with an increase nanorod concentration, the light absorption grew linearly; however, charge extraction was also depen... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Development-2021 The field of building-integrated photovoltaics (BIPV) has gained attention from the scientific community due to its potential to reduce pollution and materials and electricity costs, as well as to improve the aesthetics of a building. In recent years, scientists have looked at... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Development-2022 Photosensitizers are dye compounds that absorb the photons from incoming light and eject electrons, producing an electric current that can be used to power a device or a storage unit. According to a new study performed by Michael Grätzel and fellow scientist Anders Hagfeldt, a... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Market introduction-Several commercial providers are promising availability of DSCs in the near future: Fujikura is a major supplier of DSSC's for applications in IoT, smart factories, agriculture and infrastructure modelling. (See : Fujikura Ltd. | Fujikura Releases thin Dye-Sensitized Solar ... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Market introduction-Dyesol officially opened its new manufacturing facilities in Queanbeyan Australia on 7 October 2008. It has subsequently announced partnerships with Tata Steel (TATA-Dyesol) and Pilkington Glass (Dyetec-Solar) for the development and large scale manufacture of DSC BIPV. Dye... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Market introduction-Solaronix, a Swiss company specialized in the production of DSC materials since 1993, has extended their premises in 2010 to host a manufacturing pilot line of DSC modules. | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Market introduction-SolarPrint was founded in Ireland in 2008 by Dr. Mazhar Bari, Andre Fernon and Roy Horgan. SolarPrint was the first Ireland-based commercial entity involved in the manufacturing of PV technology. SolarPrint's innovation was the solution to the solvent-based electrolyte whic... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Market introduction-G24innovations founded in 2006, based in Cardiff, South Wales, UK. On 17 October 2007, claimed the production of the first commercial grade dye sensitised thin films.
Sony Corporation has developed dye-sensitized solar cells with an energy conversion efficiency of 10%, a le... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Market introduction-H.Glass was founded 2011 in Switzerland. H.Glass has put enormous efforts to create industrial process for the DSSC technology – the first results where shown at the EXPO 2015 in Milano at the Austrian Pavilion. The milestone for DSSC is the Science Tower in Austria – it is... | milkshake721/2.1M-wiki-STEM |
Dye-sensitized solar cell-Market introduction-Exeger Operations AB, Sweden, has built a factory in Stockholm with a capacity of 300,000m2. SoftBank Group Corp. has made two investments of US$10M in Exeger during 2019. [1] | milkshake721/2.1M-wiki-STEM |
Barium sulfite-Barium sulfite-Barium sulfite is the inorganic compound with the chemical formula BaSO3. It is a white powder that finds few applications. It is an intermediate in the carbothermal reduction of barium sulfate to barium sulfide: BaSO4 + CO → BaSO3 + CO2 | milkshake721/2.1M-wiki-STEM |
Metabolic typing-Metabolic typing-Metabolic typing is a pseudoscience whose proponents believe that each person has a unique metabolism, and that the proportion of macromolecules (proteins, carbohydrates and fats) which are optimal for one person may not be for a second, and could even be detrimental to them. | milkshake721/2.1M-wiki-STEM |
Metabolic typing-Metabolic typing-Metabolic typing uses common visible symptoms related to the skin, eyes, and other parts of the body to assess different aspects of a person's metabolism and categorize them into broad metabolic types. In addition, some proponents of metabolic typing use tests such as hair analysis to ... | milkshake721/2.1M-wiki-STEM |
Metabolic typing-Background-Metabolic typing was introduced by William Donald Kelley, a dentist, in the 1960s. Kelley advocated basing dietary choices on the activity of one's sympathetic and parasympathetic nervous systems. In 1970, Kelley was convicted of practicing medicine without a license, as he had diagnosed a p... | milkshake721/2.1M-wiki-STEM |
Metabolic typing-Effectiveness-Some metabolic typing companies use a battery of blood and urine tests performed by reputable laboratories, but interpret the results in an unconventional and medically questionable fashion. During a 1985 investigation into one such firm, an investigator sent two separate samples of his o... | milkshake721/2.1M-wiki-STEM |
Metabolic typing-Metabolic therapies-"Metabolic therapy", including administration of laetrile, was promoted for cancer patients by John Richardson in the San Francisco Bay Area in the 1970s, until his arrest for violating the California Cancer Law and revocation of his license by the California Board of Medical Qualit... | milkshake721/2.1M-wiki-STEM |
Metabolic typing-Metabolic diet-William Donald Kelley, in his book, classified the Metabolism of an individual into three categories. Few are fast oxidizer, few are a slow oxidizer. Some have a normal rate of food oxidization called mixed oxidizer. Based on this rate of oxidization the Diet (nutrition) for an individua... | milkshake721/2.1M-wiki-STEM |
Planets in science fiction-Planets in science fiction-Planets in science fiction are fictional planets that appear in various media of the science fiction genre as story-settings or depicted locations. | milkshake721/2.1M-wiki-STEM |
Planets in science fiction-Planet lists-For planets from specific fictional milieux, use the following lists: Literature Alliance–Union Universe by C. J. Cherryh: planet list The works of Hal Clement: planet list Childe Cycle by Gordon R. Dickson: planet list Demon Princes by Jack Vance: planet list Known Space by Larr... | milkshake721/2.1M-wiki-STEM |
Planets in science fiction-List of planets-Planets and the works or franchise they appear in. This lists planets that have their own Wikipedia articles. | milkshake721/2.1M-wiki-STEM |
Stone carving-Stone carving-Stone carving is an activity where pieces of rough natural stone are shaped by the controlled removal of stone. Owing to the permanence of the material, stone work has survived which was created during our prehistory or past time.
Work carried out by paleolithic societies to create stone too... | milkshake721/2.1M-wiki-STEM |
Stone carving-Stone carving-Stone carving is one of the processes which may be used by an artist when creating a sculpture. The term also refers to the activity of masons in dressing stone blocks for use in architecture, building or civil engineering. It is also a phrase used by archaeologists, historians, and anthropo... | milkshake721/2.1M-wiki-STEM |
Stone carving-History-The earliest known works of representational art are stone carvings. Often marks carved into rock or petroglyphs will survive where painted work will not. Prehistoric Venus figurines such as the Venus of Berekhat Ram may be as old as 250,000 years, and are carved in stones such as tuff and limesto... | milkshake721/2.1M-wiki-STEM |
Stone carving-History-Prior to the discovery of steel by any culture, all stone carving was carried out by using an abrasion technique, following rough hewing of the stone block using hammers. The reason for this is that bronze, the hardest available metal until steel, is not hard enough to work any but the softest sto... | milkshake721/2.1M-wiki-STEM |
Stone carving-History-The development of iron made possible stone carving tools, such as chisels, drills and saws made from steel, that were capable of being hardened and tempered to a state hard enough to cut stone without deforming, while not being so brittle as to shatter. Carving tools have changed little since the... | milkshake721/2.1M-wiki-STEM |
Stone carving-History-One modern stone carving technique uses a new process: The technique of applying sudden high temperature to the surface. The expansion of the top surface due to the sudden increase in temperature causes it to break away. On a small scale, Oxy-acetylene torches are used. On an industrial scale, las... | milkshake721/2.1M-wiki-STEM |
Stone carving-Stone sculpture-Carving stone into sculpture is an activity older than civilization itself. Prehistoric sculptures were usually human forms, such as the Venus of Willendorf and the faceless statues of the Cycladic cultures. Later cultures devised animal, human-animal and abstract forms in stone. The earli... | milkshake721/2.1M-wiki-STEM |
Stone carving-Stone sculpture-The process begins with the selection of a stone for carving. Some artists use the stone itself as inspiration; the Renaissance artist Michelangelo claimed that his job was to free the human form trapped inside the block. Other artists begin with a form already in mind and find a stone to ... | milkshake721/2.1M-wiki-STEM |
Stone carving-Stone sculpture-When ready to carve, the artist usually begins by knocking off large portions of unwanted stone. This is the "roughing out" stage of the sculpting process. For this task they may select a point chisel, which is a long, hefty piece of steel with a point at one end and a broad striking surfa... | milkshake721/2.1M-wiki-STEM |
Stone carving-Stone sculpture-Once the general shape of the statue has been determined, the sculptor uses other tools to refine the figure. A toothed chisel or claw chisel has multiple gouging surfaces which create parallel lines in the stone. These tools are generally used to add texture to the figure. An artist might... | milkshake721/2.1M-wiki-STEM |
Stone carving-Stone sculpture-Eventually the sculptor has changed the stone from a rough block into the general shape of the finished statue. Tools called rasps and rifflers are then used to enhance the shape into its final form. A rasp is a flat, steel tool with a coarse surface. The sculptor uses broad, sweeping stro... | milkshake721/2.1M-wiki-STEM |
Stone carving-Stone sculpture-The final stage of the carving process is polishing. Sandpaper can be used as a first step in the polishing process, or sand cloth. Emery, a stone that is harder and rougher than the sculpture media, is also used in the finishing process. This abrading, or wearing away, brings out the colo... | milkshake721/2.1M-wiki-STEM |
Stone carving-Stone sculpture-Sculptures can be carved via either the direct or the indirect carving method. Indirect carving is a way of carving by using an accurate clay, wax or plaster model, which is then copied with the use of a compass or proportional dividers or a pointing machine. The direct carving method is a... | milkshake721/2.1M-wiki-STEM |
Stone carving-Stone carving considerations-Stone has been used for carving since ancient times for many reasons. Most types of stone are easier to find than metal ores, which have to be mined and smelted. Stone can be dug from the surface and carved with hand tools. Stone is more durable than wood, and carvings in ston... | milkshake721/2.1M-wiki-STEM |
Stone carving-Stone carving considerations-Soft stone such as chalk, soapstone, pumice and Tufa can be easily carved with found items such as harder stone or in the case of chalk even the fingernail.
Limestones and marbles can be worked using abrasives and simple iron tools.
Granite, basalt and some metamorphic stone i... | milkshake721/2.1M-wiki-STEM |
Stone carving-Stone shaping and tools-Basic stone carving tools fall into five categories: Percussion tools for hitting - such as mallets, axes, adzes, bouchards and toothed hammers.
Tools for rough shaping of stone, to form a block the size needed for the carving. These include feathers and wedges and pitching tools.
... | milkshake721/2.1M-wiki-STEM |
Stone carving-Stone shaping and tools-Abrasives for material removals - such as carborundum blocks, drills, saws, grinding and cutting wheels, water-abrasive machinery and dressing tools such as French and English drags.More advanced processes, such as laser cutting and jet torches, use sudden high temperature with a c... | milkshake721/2.1M-wiki-STEM |
Stone carving-Stone shaping and tools-The use of chisels for stone carving is possible in several ways. Two are: The mason's stroke, in which a flat chisel is used at approximately 90 degrees to the surface in an organized sweep. It shatters the stone beneath it and each successive pass lowers the surface. | milkshake721/2.1M-wiki-STEM |
Stone carving-Stone shaping and tools-The lettering stroke, in which the chisel is used along the surface at approximately 30 degrees to cut beneath the existing surface.There are many types and styles of stone carving tools, each carver will decide for themselves which tools to use. Traditionalists might use hand tool... | milkshake721/2.1M-wiki-STEM |
Stone carving-Stone shaping and tools-Fishtail carving chisels are used to create pockets, valleys and for intricate carving, whilst providing good visibility around the stone.
Masonry chisels are used for the general shaping of stones.
Stone point tools are used to rough out the surface of the stone.
Stone claw tools ... | milkshake721/2.1M-wiki-STEM |
Stone carving-Stone shaping and tools-Stone nickers are used to split stones by tracing a line along the stone with progressive strikes until the stone breaks along the line.Powered pneumatic hammers make the hard work easier. Progress on shaping stone is faster with pneumatic carving tools. Air hammers (such as Cuturi... | 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.