"Janka hardness test The Janka hardness test (from the Austrian-born emigrant Gabriel Janka, 1864-1932) measures the resistance of a sample of wood to denting and wear. It measures the force required to embed an diameter steel ball halfway into a sample of wood. A common use of Janka hardness ratings is to determine whether a species is suitable for use as flooring. The hardness of wood varies with the direction of the wood grain. Testing on the surface of a plank, perpendicular to the grain, is said to be of ""side hardness"". Testing the cut surface of a stump is"
"Janka hardness test results tabulated below were done in accordance with ASTM D 1037-12 testing methods. Lumber stocks tested range from 1"" to 2"" thick. The tabulated Janka hardness numbers are an average. There is a standard deviation associated with each species, but these values are not given. No testing was done on actual flooring. Other factors affect how flooring performs: the type of core for engineered flooring such as pine, HDF, poplar, oak, birch; grain direction and thickness; floor or top wear surface, etc. The chart is not to be considered an absolute; it is meant to help people"
"over competing hardness tests. The typical test uses a diameter steel ball as an indenter with a force. For softer materials, a smaller force is used; for harder materials, a tungsten carbide ball is substituted for the steel ball. The indentation is measured and hardness calculated as: where: Brinell hardness is sometimes quoted in megapascals; the Brinell hardness number is multiplied by the acceleration due to gravity, 9.80665 m/s, to convert it to megapascals. The BHN can be converted into the ultimate tensile strength (UTS), although the relationship is dependent on the material, and therefore determined empirically. The relationship is"
"Vickers hardness test The Vickers hardness test was developed in 1921 by Robert L. Smith and George E. Sandland at Vickers Ltd as an alternative to the Brinell method to measure the hardness of materials. The Vickers test is often easier to use than other hardness tests since the required calculations are independent of the size of the indenter, and the indenter can be used for all materials irrespective of hardness. The basic principle, as with all common measures of hardness, is to observe the questioned material's ability to resist plastic deformation from a standard source. The Vickers test can"
"content have all been correlated with ceramic properties such as mechanical strength σ by the Hall–Petch equation. Hardness, toughness, dielectric constant and many other properties are microstructure-dependent. The hardness of a material can be measured in many ways. The Knoop hardness test, a method of microindention hardness, is the most reproducible for dense ceramics. The Vickers hardness test and superficial Rockwell scales (e.g., 45N) can also be used, but tend to cause more surface damage than Knoop. The Brinell test is suitable for ductile metals, but not ceramics. In the Knoop test, a diamond indenter in the shape of an"
"aggregated diamond nanorods, which is harder than bulk diamond and is currently the hardest (~150 GPa) material known. Superhard material A superhard material is a material with a hardness value exceeding 40 gigapascals (GPa) when measured by the Vickers hardness test. They are highly incompressible solids with high electron density and high bond covalency. As a result of their unique properties, these materials are of great interest in many industrial areas including, but not limited to, abrasives, polishing and cutting tools and wear-resistant and protective coatings. Diamond is the hardest known material to date, with a Vickers hardness in the"
"Superhard material A superhard material is a material with a hardness value exceeding 40 gigapascals (GPa) when measured by the Vickers hardness test. They are highly incompressible solids with high electron density and high bond covalency. As a result of their unique properties, these materials are of great interest in many industrial areas including, but not limited to, abrasives, polishing and cutting tools and wear-resistant and protective coatings. Diamond is the hardest known material to date, with a Vickers hardness in the range of 70–150 GPa. Diamond demonstrates both high thermal conductivity and electrically insulating properties and much attention has"
"dense, wood is resistant to the elements and is used for construction, carpentry, beams for bridges, poles and firewood. The wood is said to be unaffected by insects including termites and it can last more than 20 years unpainted. It has a ""Janka Hardness"" of 2300-3700 lb., a parallel ""bending strength"" of 16900 psi, a parallel ""compression strength"" of 8500 psi and a density of 720–1199 kg/m³ at a moisture content of 12-15%. Its modulus of elasticity is 157 801 kg/cm². For hardwood flooring it is called ""Pepperwood."" Parapiptadenia rigida Parapiptadenia rigida is a perennial shrub or tree. It is"
"with their primary constituent being bufotenin. The wood from ""A. peregrina"" is very hard and it is good for making furniture. It has a Janka rating of 3700 lb. and a density of around 0.86 g/cm³. The beans (sometimes called seeds) and falling leaves are hallucinogenic and are toxic to cattle. Chemical compounds contained in ""A. peregrina"" include: The bark contains a high percentage of tannins, 587 mg CE/g extract. Archaeological evidence shows ""Anadenanthera"" beans have been used as hallucinogens for thousands of years. The oldest clear evidence of use comes from smoking pipes made of puma bone (""Felis concolor"")"
"test is that it is less sensitive to the applied load, especially compared to the Brinell hardness test. For cold worked materials the Meyer hardness is relatively constant and independent of load, whereas for the Brinell hardness test it decreases with higher loads. For annealed materials the Meyer hardness increases continuously with load due to strain hardening. Based on Meyer's law hardness values from this test can be converted into Brinell hardness values, and vice versa. The Meyer hardness test was devised by Eugene Meyer of the Materials Testing Laboratory at the Imperial School of Technology, Charlottenburg, Germany, circa 1908."
"range from 3000 to over 5000 using the Janka hardness test. Other flooring materials have comparable Janka ratings, with a higher number indicating a harder material: red oak (1290); white oak (1360); rock maple (1450); hickory (1820); and Brazilian Cherry / Jatoba (2350). Different forms of bamboo flooring exist. Each varies in its manufacturing process and differs largely based on economic viability and local preferences. The most common form, particularly in southeast Asia, uses thin bamboo stems that are cut as flat as possible. They are cut to similar lengths and can be stained, varnished, or simply used as is."
"called a test of ""end hardness"". Side hardness may be further divided into ""radial hardness"" and ""tangential hardness"", although the differences are minor and often neglected. The results are stated in various ways, which can lead to confusion, especially when the actual units employed are often not attached. Overall, the resulting measure is always one of force. In the United States, the measurement is in pounds-force (lbf). In Sweden it is in kilograms-force (kgf), and in Australia, either in newtons (N) or kilonewtons (kN). This confusion is greatest when the results are treated as units, for example ""660 Janka"". The"
"ranks highest of the trade woods, with a Janka hardness of 4500 lbf (compared with Olneya at 3260 lbf, African Blackwood at 2940 lbf, Hickory at 1820 lbf, red oak at 1290 lbf, Yellow Pine at 690 lbf, and Balsa at 100 lbf). The densest of all woods is Allocasuarina luehmannii . Various other hardwoods may also be called lignum vitae and should not be confused with it. The best-known come from ""Bulnesia arborea"" and ""Bulnesia sarmientoi"" (in the same subfamily as ""Guaiacum"") and are known as Verawood or Argentine lignum vitae; they are somewhat similar in appearance and working"
"a 2003 research published in ""Pharmacotherapy"", neither the Marquis, Mecke, nor Simon's reagents should be used by the public for harm reduction purposes. These agents do not help identify pure MDMA tablets. The research team suggests using gas chromatography-mass spectrometry as the most sensitive and specific testing method for identifying MDMA and its contaminants but this is out of reach for users in most countries and reagent tests remain popular, often distributed by harm-reduction organisations due to their low cost and high utility when multiple test reagents are used. Home pill testing equipment is illegal in the US state of"
"Gutka Gutka or guṭkha is a chewing tobacco preparation made of crushed areca nut, tobacco, catechu, paraffin wax, slaked lime and sweet or savory flavorings, commonly used in some parts of India. It contains carcinogens, is considered responsible for oral cancer and other severe negative health effects and hence is subjected in India to the same restrictions and warnings as cigarettes. Gutka is manufactured in India and exported to a few other countries including United States, often marketed under the guise of a ""safer"" product than cigarettes and tobacco. A mild stimulant, it is sold across South Asia in small,"
"Kurnakov test The Kurnakov test, also known as Kurnakov's reaction, is a chemical test that distinguishes pairs of cis- and trans-isomers of [PtAX] (A = NH, X = halogen or pseudohalide). Upon treatment with thiourea, the trans dihalides give less soluble white products whereas the cis dihalides give more soluble yellow products. The test is still used to assay samples of the drug cisplatin, but it is mainly of pedagogical interest, as it illustrates the trans effect. The test was devised by Soviet chemist Nikolai Semenovich Kurnakov. The Kurnakov test is sometimes used to detect transplatin in samples of the"
"test are that only a very small sample of material is required, and that it is valid for a wide range of test forces. The main disadvantages are the difficulty of using a microscope to measure the indentation (with an accuracy of 0.5 micrometre), and the time needed to prepare the sample and apply the indenter. Variables such as load, temperature, and environment, may affect this procedure, which have been examined in detail. Knoop hardness test The Knoop hardness test is a microhardness test – a test for mechanical hardness used particularly for very brittle materials or thin sheets, where"
"For some modern anti-armor weapons, molybdenum and pseudo-alloys of tungsten filler and copper binder (9:1, thus density is ≈18 Mg/m) have been adopted. Nearly every common metallic element has been tried, including aluminum, tungsten, tantalum, depleted uranium, lead, tin, cadmium, cobalt, magnesium, titanium, zinc, zirconium, molybdenum, beryllium, nickel, silver, and even gold and platinum. The selection of the material depends on the target to be penetrated; for example, aluminum has been found advantageous for concrete targets. In early antitank weapons, copper was used as a liner material. Later, in the 1970s, it was found tantalum is superior to copper, due"
"is a series of chemical solutions that turn to the color of purple when the vegetation of marijuana is added. Van Urk reagent turns blue-purple when in the presence of LSD. Scott Test's chemical solution shows up as a faint blue for cocaine base. Saliva / oral fluid-based drug tests can generally detect use during the previous few days. Is better at detecting very recent use of a substance. THC may only be detectable for 2–24 hours in most cases. On site drug tests are allowed per the Department of Labor. Detection in saliva tests begins almost immediately upon use"
"be used for all metals and has one of the widest scales among hardness tests. The unit of hardness given by the test is known as the Vickers Pyramid Number (HV) or Diamond Pyramid Hardness (DPH). The hardness number can be converted into units of pascals, but should not be confused with pressure, which uses the same units. The hardness number is determined by the load over the surface area of the indentation and not the area normal to the force, and is therefore not pressure. It was decided that the indenter shape should be capable of producing geometrically similar"
"skirt the ban on advertising tobacco products. Surrogate advertisements often use pan masala ads to promote gutka products with similar name and packaging. According to the Food Safety and Standards (Prohibition and Restriction on Sales) Regulations, 2011 of the Food Safety and Standards Authority of India, misleading advertisement of such products invites a fine of 1,000,000 rupees. Gutka Gutka or guṭkha is a chewing tobacco preparation made of crushed areca nut, tobacco, catechu, paraffin wax, slaked lime and sweet or savory flavorings, commonly used in some parts of India. It contains carcinogens, is considered responsible for oral cancer and other"
"higher the hardenability. This information is plotted on a hardenability graph. The Jominy end-quench test was invented by Walter E. Jominy (1893-1976) and A.L. Boegehold, metallurgists in the Research Laboratories Division of General Motors Corp., in 1937. For his pioneering work in heat treating, Jominy was recognized by the American Society for Metals (ASM) with its Albert Sauveur Achievement Award in 1944. Jominy served as president of ASM in 1951. Hardenability The hardenability of a metal alloy is the depth to which a material is hardened after putting it through a heat treatment process. The unit of hardenability is length."
"The trend today is to use liquid chromatography tandem mass spectrometry, preceded with sample workup as liquid-liquid extraction or solid phase extraction. Older methods include: spot test (see Pill testing), typically the Marquis Reagent, Mecke Reagent, and Froehde's reagent for opiates, Marquis Reagent and Simon's reagent for amphetamine, methamphetamine and other analogs, like MDMA, the Scott's test for cocaine, and the modified Duquenois reagent for marijuana and other cannabinoids. For compounds that don't have a common spot test, like benzodiazepines, another test may be used, typically mass spectrometry, or spectrophotometry. Forensic toxicology Forensic toxicology is the use of toxicology and"
"Brinell test, Rockwell test and the Vickers hardness test. The data on iron is so consistent that it is often used to calibrate measurements or to compare tests. However, the mechanical properties of iron are significantly affected by the sample's purity: pure, single crystals of iron are actually softer than aluminium, and the purest industrially produced iron (99.99%) has a hardness of 20–30 Brinell. An increase in the carbon content will cause a significant increase in the hardness and tensile strength of iron. Maximum hardness of 65 R is achieved with a 0.6% carbon content, although the alloy has low"
"Boron carbide Boron carbide (chemical formula approximately BC) is an extremely hard boron–carbon ceramic, and covalent material used in tank armor, bulletproof vests, engine sabotage powders, as well as numerous industrial applications. With a Vickers Hardness of >30 GPa, it is one of the hardest known materials, behind cubic boron nitride and diamond. Boron carbide was discovered in 19th century as a by-product of reactions involving metal borides, but its chemical formula was unknown. It was not until the 1930s that the chemical composition was estimated as BC. There remained, however, controversy as to whether or not the material had"
"kg/mm (10 – 15 GPa), and many carbides are over 2000 (20 GPa). The method is specified in ASTM C849, C1326 & E384. Microindention hardness is also called microindentation hardness or simply microhardness. The hardness of very small particles and thin films of ceramics, on the order of 100 nm, can be measured by nanoindentation methods that use a Berkovich indenter. The toughness of ceramics can be determined from a Vickers test under a load of 10 – 20 kg. Toughness is the ability of a material to resist crack propagation. Several calculations have been formulated from the load (P),"
"Barcol hardness test The Barcol hardness test characterizes the indentation hardness of materials through the depth of penetration of an indentor, loaded on a material sample and compared to the penetration in a reference material. The method is most often used for composite materials such as reinforced thermosetting resins or to determine how much a resin or plastic has cured. The test complements the measurement of glass transition temperature, as an indirect measure of the degree of cure of a composite. It is inexpensive and quick, and provides information on the cure throughout a part. Originally called the Barber-Colman Impressor,"
"glycosylated hemoglobin (chiefly HbA1c), which is an indicator of long term hyperglycemia in diabetes mellitus. Borax alone does not have a high affinity for the ""hardness cations"", although it has been used for water-softening. Its chemical equation for ""water-softening"" is given below: The sodium ions introduced do not make water ‘hard’. This method is suitable for removing both temporary and permanent types of hardness. A mixture of borax and ammonium chloride is used as a flux when welding iron and steel. It lowers the melting point of the unwanted iron oxide (scale), allowing it to run off. Borax is also"
"different mechanical properties than their counterpart such as higher hardness, higher fracture toughness, and high ductility. These properties are far from ceramics which behave as brittle, low ductile materials. Titanium dioxide (), has been shown to have increased hardness and ductility at the nanoscale. In an experiment, grains of titanium dioxide that had an average size of 12 nanometers were compressed at 1.4 GPa and sintered at 200 °C. The result was a grain hardness of about 2.2 times greater than that of grains of titanium dioxide with an average size of 1.3 micrometers at the same temperature and pressure."
"Brinell hardness number (BHN or more commonly HB), the conditions of the test used to obtain the number must be specified. (HB is not related to the ""HB"" degree of pencil hardness.) The standard format for specifying tests can be seen in the example ""HBW 10/3000"". ""HBW"" means that a tungsten carbide (from the chemical symbol for tungsten or from the Swedish/German name for tungsten, ""Wolfram"") ball indenter was used, as opposed to ""HBS"", which means a hardened steel ball. The ""10"" is the ball diameter in millimeters. The ""3000"" is the force in kilograms force. The hardness may also"
"Knoop hardness test The Knoop hardness test is a microhardness test – a test for mechanical hardness used particularly for very brittle materials or thin sheets, where only a small indentation may be made for testing purposes. A pyramidal diamond point is pressed into the polished surface of the test material with a known (often 100g) load, for a specified dwell time, and the resulting indentation is measured using a microscope. The geometry of this indenter is an extended pyramid with the length to width ratio being 7:1 and respective face angles are 172 degrees for the long edge and"
"However, defects can actually strengthen some covalent structures. Traditionally, high-pressure and high-temperature (HPHT) conditions have been used to synthesize superhard materials, but recent superhard material syntheses aim at using less energy and lower cost materials. Historically, hardness was first defined as the ability of one material to scratch another and quantified by an integer (sometimes half-integer) from 0 to 10 on the Mohs scale. This scale was however quickly found too discrete and non-linear. Measuring the mechanical hardness of materials changed to using a nanoindenter (usually made of diamond) and evaluating bulk moduli, and the Brinell, Rockwell, Knoop and Vickers"
"Jenkem Jenkem is an inhalant and hallucinogen created from fermented human waste. In the mid-1990s, it was reported to be a popular street drug among Zambian street children. They would put the feces and urine in a jar and cover it with a balloon then let it ferment out in the sun, then afterwards they would inhale the fumes created. In November 2007, there was a moral panic in the United States after widespread reports of jenkem becoming a popular recreational drug in middle and high schools across the country, though the true extent of the practice has since been"