1.
Utility knife
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A utility knife is a knife used for general or utility purposes. Craft knives are mostly used for crafts. Today, the utility knife also includes small folding or retractable-blade knives suited for use in the modern workplace or in the construction industry. There is also a utility knife for kitchen use which is between a chefs knife and paring knife in size, the fixed-blade utility knife was developed some 500,000 years ago, when human ancestors began to make knives made of stone. These knives were general-purpose tools, designed for cutting and shaping wooden implements, scraping hides, preparing food, by the 19th century the fixed-blade utility knife had evolved into a steel-bladed outdoors field knife capable of butchering game, cutting wood, and preparing campfires and meals. With the invention of the backspring, pocket-size utility knives were introduced with folding blades and other folding tools designed to increase the utility of the overall design. The folding pocketknife and utility tool is typified by the Camper or Boy Scout pocketknife, the U. S. folding utility knife, the Swiss Army Knife, the fixed or folding blade utility knife is popular for both indoor and outdoor use. One of the most popular types of utility knife is the retractable or folding utility knife. These types of utility knives are designed as cutting tools for use in a variety of trades. In British, Australian and New Zealand English, along with Dutch and Austrian German and this name is a genericised trademark named after Stanley Works, a manufacturer of such knives. In Israel and Switzerland, these knives are known as Japanese knives, in Brazil they are known as estiletes or cortadores Olfa. In Portugal and Canada they are known as X-Acto. In India, the Philippines, France, Italy, Egypt, in the Flemish region of Belgium it is called cuttermes. In Turkey, they are known as maket bıçağı, other names for the tool are box cutter or boxcutter, razor blade knife, razor knife, carpet knife, pen knife, stationery knife, sheetrock knife, or drywall knife. Utility knives may use fixed, folding, or retractable or replaceable blades, large fixed-blade utility knives are most often employed in an outdoors context, such as fishing, camping, or hunting. Outdoor utility knives typically feature sturdy blades from 100 to 150 millimetres in length, with edge geometry designed to resist chipping, the term utility knife may also refer to small fixed-blade knives used for crafts, model-making and other artisanal projects. These small knives feature light-duty blades best suited for cutting thin, the small, thin blade and specialized handle permit cuts requiring a high degree of precision and control. The largest construction or workplace utility knives typically feature retractable and replaceable blades, some use standard razor blades, others specialized double-ended utility blades
2.
Dissection
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Dissection, is the dismembering of the body of a deceased animal or plant to study its anatomical structure. Autopsy is used in pathology and forensic medicine to determine the cause of death in humans and it is carried out by or demonstrated to biology and anatomy students in high school and medical school. Less advanced courses typically focus on subjects, such as small formaldehyde-preserved animals. Consequently, dissection is typically conducted in a morgue or in an anatomy lab, dissection has been used for centuries to explore anatomy. Objections to the use of cadavers have led to the use of alternatives including virtual dissection of computer models, plant and animal bodies are dissected to analyze the structure and function of its components. Dissection is practised by students in courses of biology, botany, zoology, and veterinary science, in medical schools, students dissect human cadavers to learn anatomy. Dissection is used to help to determine the cause of death in autopsy and is an part of forensic medicine. A key principle in the dissection of human cadavers is the prevention of disease to the dissector. Specimens are dissected in morgues or anatomy labs, when provided, they are evaluated for use as a fresh or prepared specimen. A fresh specimen may be dissected within some days, retaining the characteristics of a living specimen, a prepared specimen may be preserved in solutions such as formalin and pre-dissected by an experienced anatomist, sometimes with the help of a diener. This preparation is sometimes called prosection, most dissection involves the careful isolation and removal of individual organs, called the Virchow technique. An alterative more cumbersome technique involves the removal of the organ body. This technique allows a body to be sent to a director without waiting for the sometimes time-consuming dissection of individual organs. Dissection of individual organs involves accessing the area in which the organ is situated, for example, when removing the heart, connects such as the superior vena cava and inferior vena cava are separated. If pathological connections exist, such as a fibrous pericardium, then this may be deliberately dissected along with the organ, Human dissections were carried out by the Greek physicians Herophilus of Chalcedon and Erasistratus of Chios in the early part of the third century BC. During this period, the first exploration into full human anatomy was performed rather than a base knowledge gained from problem-solution delving, before and after this time investigators appeared to largely limit themselves to animals. While there was a taboo within the Greek culture concerning human dissection. For a time, Roman law forbade dissection and autopsy of the human body, Galen, for example, dissected the Barbary macaque and other primates, assuming their anatomy was basically the same as that of humans
3.
Handicraft
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One of the worlds oldest handicraft is Dhokra, this is a sort of metal casting has been used in India for over 4,000 years and is still used. Collective terms for handicrafts include artisanry, handicrafting, crafting, many handicrafters use natural, even entirely indigenous, materials while others may prefer modern, non-traditional materials, and even upcycle industrial materials. The individual artisanship of an item is the paramount criterion. Most crafts require the development of skill and the application of patience, like folk art, handicraft output often has cultural and/or religious significance, and increasingly may have a political message as well, as in craftivism. The Arts and Crafts movement originated as a late 19th-century design reform and social movement principally in Europe, North America and Australia and this was held up in contrast to what was perceived to be the alienating effects of industrial labor. These activities were called crafts because originally many of them were professions under the guild system, adolescents were apprenticed to a master craftsman, and refined their skills over a period of years in exchange for low wages. Simple arts and crafts projects are an elementary and middle school activity in both mainstream and alternative education systems around the world. e. The use of traditional handicrafting techniques by professional fine artists, many community centers and schools run evening or day classes and workshops, for adults and children, offering to teach basic craft skills in a short period of time. If sold, they are sold in Direct sales, Gift shops, Public markets, in developing countries, handicrafts are sold to locals and as Souvenirs to tourists. Sellers tend to speak at least a few words of common tourist languages
4.
Stainless steel
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In metallurgy, stainless steel, also known as inox steel or inox from French inoxydable, is a steel alloy with a minimum of 10. 5% chromium content by mass. Stainless steel is notable for its resistance, and it is widely used for food handling. Stainless steel does not readily corrode, rust or stain with water as ordinary steel does, however, it is not fully stain-proof in low-oxygen, high-salinity, or poor air-circulation environments. There are various grades and surface finishes of stainless steel to suit the environment the alloy must endure, Stainless steel is used where both the properties of steel and corrosion resistance are required. Stainless steel differs from carbon steel by the amount of chromium present, unprotected carbon steel rusts readily when exposed to air and moisture. This iron oxide film is active and accelerates corrosion by making it easier for more iron oxide to form, since iron oxide has lower density than steel, the film expands and tends to flake and fall away. In comparison, stainless steels contain sufficient chromium to undergo passivation and this layer prevents further corrosion by blocking oxygen diffusion to the steel surface and stops corrosion from spreading into the bulk of the metal. Passivation occurs only if the proportion of chromium is high enough, Stainless steel’s resistance to corrosion and staining, low maintenance, and familiar lustre make it an ideal material for many applications. Storage tanks and tankers used to transport orange juice and other food are made of stainless steel. This also influences its use in kitchens and food processing plants, as it can be steam-cleaned and sterilized. High oxidation resistance in air at ambient temperature is achieved with addition of a minimum of 13% chromium. The chromium forms a layer of chromium oxide when exposed to oxygen. The layer is too thin to be visible, and the metal remains lustrous, the layer is impervious to water and air, protecting the metal beneath, and this layer quickly reforms when the surface is scratched. This phenomenon is called passivation and is seen in other metals, corrosion resistance can be adversely affected if the component is used in a non-oxygenated environment, a typical example being underwater keel bolts buried in timber. When stainless steel parts such as nuts and bolts are forced together, when forcibly disassembled, the welded material may be torn and pitted, a destructive effect known as galling. Galling can be avoided by the use of materials for the parts forced together, for example bronze and stainless steel. However, two different alloys electrically connected in a humid, even mildly acidic environment may act as a voltaic pile, nitronic alloys, made by selective alloying with manganese and nitrogen, may have a reduced tendency to gall. Additionally, threaded joints may be lubricated to provide a film between the two parts and prevent galling, low-temperature carburizing is another option that virtually eliminates galling and allows the use of similar materials without the risk of corrosion and the need for lubrication
5.
Titanium
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Titanium is a chemical element with symbol Ti and atomic number 22. It is a transition metal with a silver color, low density. Titanium is resistant to corrosion in sea water, aqua regia, titanium was discovered in Cornwall, Great Britain, by William Gregor in 1791, and it is named by Martin Heinrich Klaproth for the Titans of Greek mythology. The metal is extracted from its principal mineral ores by the Kroll, the most common compound, titanium dioxide, is a popular photocatalyst and is used in the manufacture of white pigments. Other compounds include titanium tetrachloride, a component of smoke screens and catalysts, and titanium trichloride, the two most useful properties of the metal are corrosion resistance and strength-to-density ratio, the highest of any metallic element. In its unalloyed condition, titanium is as strong as some steels, there are two allotropic forms and five naturally occurring isotopes of this element, 46Ti through 50Ti, with 48Ti being the most abundant. Although they have the number of valence electrons and are in the same group in the periodic table. As a metal, titanium is recognized for its high strength-to-weight ratio and it is a strong metal with low density that is quite ductile, lustrous, and metallic-white in color. The relatively high melting point makes it useful as a refractory metal and it is paramagnetic and has fairly low electrical and thermal conductivity. Commercial grades of titanium have ultimate tensile strength of about 434 MPa, equal to that of common, low-grade steel alloys, titanium is 60% denser than aluminium, but more than twice as strong as the most commonly used 6061-T6 aluminium alloy. Certain titanium alloys achieve tensile strengths of over 1400 MPa, however, titanium loses strength when heated above 430 °C. Titanium is not as hard as some grades of heat-treated steel, it is non-magnetic, machining requires precautions, because the material might gall unless sharp tools and proper cooling methods are used. Like steel structures, those made from titanium have a limit that guarantees longevity in some applications. The metal is an allotrope of an hexagonal α form that changes into a body-centered cubic β form at 882 °C. The specific heat of the α form increases dramatically as it is heated to this transition temperature but then falls, similar to zirconium and hafnium, an additional omega phase exists, which is thermodynamically stable at high pressures, but metastable at ambient pressures. This phase is usually hexagonal or trigonal and can be considered to be due to a soft longitudinal acoustic phonon of the β phase causing collapse of planes of atoms, like aluminium and magnesium, titanium metal and its alloys oxidize immediately upon exposure to air. Titanium readily reacts with oxygen at 1,200 °C in air and it is, however, slow to react with water and air at ambient temperatures because it forms a passive oxide coating that protects the bulk metal from further oxidation. When it first forms, this layer is only 1–2 nm thick but continues to grow slowly
6.
Diamond
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Diamond is a metastable allotrope of carbon, where the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice. Diamond is less stable than graphite, but the rate from diamond to graphite is negligible at standard conditions. Diamond is renowned as a material with superlative physical qualities, most of which originate from the covalent bonding between its atoms. In particular, diamond has the highest hardness and thermal conductivity of any bulk material and those properties determine the major industrial application of diamond in cutting and polishing tools and the scientific applications in diamond knives and diamond anvil cells. Because of its extremely rigid lattice, it can be contaminated by very few types of impurities, such as boron, small amounts of defects or impurities color diamond blue, yellow, brown, green, purple, pink, orange or red. Diamond also has relatively high optical dispersion, most natural diamonds are formed at high temperature and pressure at depths of 140 to 190 kilometers in the Earths mantle. Carbon-containing minerals provide the source, and the growth occurs over periods from 1 billion to 3.3 billion years. Diamonds are brought close to the Earths surface through deep volcanic eruptions by magma, Diamonds can also be produced synthetically in a HPHT method which approximately simulates the conditions in the Earths mantle. An alternative, and completely different growth technique is chemical vapor deposition, several non-diamond materials, which include cubic zirconia and silicon carbide and are often called diamond simulants, resemble diamond in appearance and many properties. Special gemological techniques have developed to distinguish natural diamonds, synthetic diamonds. The word is from the ancient Greek ἀδάμας – adámas unbreakable, the name diamond is derived from the ancient Greek αδάμας, proper, unalterable, unbreakable, untamed, from ἀ-, un- + δαμάω, I overpower, I tame. Diamonds have been known in India for at least 3,000 years, Diamonds have been treasured as gemstones since their use as religious icons in ancient India. Their usage in engraving tools also dates to early human history, later in 1797, the English chemist Smithson Tennant repeated and expanded that experiment. By demonstrating that burning diamond and graphite releases the same amount of gas, the most familiar uses of diamonds today are as gemstones used for adornment, a use which dates back into antiquity, and as industrial abrasives for cutting hard materials. The dispersion of light into spectral colors is the primary gemological characteristic of gem diamonds. In the 20th century, experts in gemology developed methods of grading diamonds, four characteristics, known informally as the four Cs, are now commonly used as the basic descriptors of diamonds, these are carat, cut, color, and clarity. A large, flawless diamond is known as a paragon and these conditions are met in two places on Earth, in the lithospheric mantle below relatively stable continental plates, and at the site of a meteorite strike. The conditions for diamond formation to happen in the mantle occur at considerable depth corresponding to the requirements of temperature and pressure
7.
Obsidian
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Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock. It is produced when felsic lava extruded from a volcano cools rapidly with minimal crystal growth, Obsidian is commonly found within the margins of rhyolitic lava flows known as obsidian flows, where the chemical composition induces a high viscosity and polymerization degree of the lava. The inhibition of atomic diffusion through this highly viscous and polymerized lava explains the lack of crystal growth. Obsidian is hard and brittle, it therefore fractures with very sharp edges, which were used in the past in cutting and piercing tools, among the various forms of glass we may reckon Obsidian glass, a substance very similar to the stone found by Obsidius in Ethiopia. Obsidian is the rock formed as a result of quickly cooled lava, tektites were once thought by many to be obsidian produced by lunar volcanic eruptions, though few scientists now adhere to this hypothesis. Obsidian is mineral-like, but not a true mineral because as a glass it is not crystalline, in addition and it is sometimes classified as a mineraloid. Though obsidian is usually dark in color similar to mafic rocks such as basalt, Obsidian consists mainly of SiO2, usually 70% or more. Crystalline rocks with obsidians composition include granite and rhyolite, because obsidian is metastable at the Earths surface, no obsidian has been found that is older than Cretaceous age. This breakdown of obsidian is accelerated by the presence of water, having a low water content when newly formed, typically less than 1% water by weight, obsidian becomes progressively hydrated when exposed to groundwater, forming perlite. Pure obsidian is usually dark in appearance, though the color varies depending on the presence of impurities, iron and other transition elements may give the obsidian a dark brown to black color. Very few samples are nearly colorless, in some stones, the inclusion of small, white, radially clustered crystals of cristobalite in the black glass produce a blotchy or snowflake pattern. Obsidian may contain patterns of gas bubbles remaining from the lava flow and these bubbles can produce interesting effects such as a golden sheen. An iridescent, rainbow-like sheen is caused by inclusions of magnetite nanoparticles, Obsidian can be found in locations which have experienced rhyolitic eruptions. Obsidian can also be found in the eastern U. S. states of Virginia, as well as Pennsylvania, there are only four major deposit areas in the central Mediterranean, Lipari, Pantelleria, Palmarola and Monte Arci. Ancient sources in the Aegean were Milos and Gyali, acıgöl town and the Göllü Dağ volcano were the most important sources in central Anatolia, one of the more important source areas in the prehistoric Near East. Use of obsidian in pottery of the Neolithic in the area around Lipari was found to be less at a distance representing two weeks journeying. Anatolian sources of obsidian are known to have been the used in the Levant. The first attested civilized use is from excavations at Tell Brak dated the late fifth millennia, Obsidian was valued in Stone Age cultures because, like flint, it could be fractured to produce sharp blades or arrowheads
8.
Silver
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Silver is a metallic element with symbol Ag and atomic number 47. The symbol Ag stems from Latin argentum, derived from the Greek ὰργὀς, a soft, white, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. The metal is found in the Earths crust in the pure, free form, as an alloy with gold and other metals. Most silver is produced as a byproduct of copper, gold, lead, Silver is more abundant than gold, but it is much less abundant as a native metal. Its purity is measured on a per mille basis, a 94%-pure alloy is described as 0.940 fine. As one of the seven metals of antiquity, silver has had a role in most human cultures. Silver has long valued as a precious metal. Silver metal is used in many premodern monetary systems in bullion coins, Silver is used in numerous applications other than currency, such as solar panels, water filtration, jewelry, ornaments, high-value tableware and utensils, and as an investment medium. Silver is used industrially in electrical contacts and conductors, in specialized mirrors, window coatings, Silver compounds are used in photographic film and X-rays. Dilute silver nitrate solutions and other compounds are used as disinfectants and microbiocides, added to bandages and wound-dressings, catheters. Silver is similar in its physical and chemical properties to its two neighbours in group 11 of the periodic table, copper and gold. This distinctive electron configuration, with an electron in the highest occupied s subshell over a filled d subshell. Silver is a soft, ductile and malleable transition metal. Silver crystallizes in a cubic lattice with bulk coordination number 12. Unlike metals with incomplete d-shells, metallic bonds in silver are lacking a covalent character and are relatively weak and this observation explains the low hardness and high ductility of single crystals of silver. Silver has a brilliant white metallic luster that can take a polish. Protected silver has greater optical reflectivity than aluminium at all wavelengths longer than ~450 nm, at wavelengths shorter than 450 nm, silvers reflectivity is inferior to that of aluminium and drops to zero near 310 nm. The electrical conductivity of silver is the greatest of all metals, greater even than copper, during World War II in the US,13540 tons of silver were used in electromagnets for enriching uranium, mainly because of the wartime shortage of copper
9.
Laser
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A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The term laser originated as an acronym for light amplification by stimulated emission of radiation, the first laser was built in 1960 by Theodore H. Maiman at Hughes Research Laboratories, based on theoretical work by Charles Hard Townes and Arthur Leonard Schawlow. A laser differs from other sources of light in that it emits light coherently, spatial coherence allows a laser to be focused to a tight spot, enabling applications such as laser cutting and lithography. Spatial coherence also allows a laser beam to stay narrow over great distances, Lasers can also have high temporal coherence, which allows them to emit light with a very narrow spectrum, i. e. they can emit a single color of light. Temporal coherence can be used to produce pulses of light as short as a femtosecond, Lasers are distinguished from other light sources by their coherence. Spatial coherence is typically expressed through the output being a narrow beam, Laser beams can be focused to very tiny spots, achieving a very high irradiance, or they can have very low divergence in order to concentrate their power at a great distance. Temporal coherence implies a polarized wave at a single frequency whose phase is correlated over a great distance along the beam. A beam produced by a thermal or other incoherent light source has an amplitude and phase that vary randomly with respect to time and position. Lasers are characterized according to their wavelength in a vacuum, most single wavelength lasers actually produce radiation in several modes having slightly differing frequencies, often not in a single polarization. Although temporal coherence implies monochromaticity, there are lasers that emit a broad spectrum of light or emit different wavelengths of light simultaneously, there are some lasers that are not single spatial mode and consequently have light beams that diverge more than is required by the diffraction limit. However, all devices are classified as lasers based on their method of producing light. Lasers are employed in applications where light of the spatial or temporal coherence could not be produced using simpler technologies. The word laser started as an acronym for light amplification by stimulated emission of radiation, in the early technical literature, especially at Bell Telephone Laboratories, the laser was called an optical maser, this term is now obsolete. A laser that produces light by itself is technically an optical rather than an optical amplifier as suggested by the acronym. It has been noted that the acronym LOSER, for light oscillation by stimulated emission of radiation. With the widespread use of the acronym as a common noun, optical amplifiers have come to be referred to as laser amplifiers. The back-formed verb to lase is frequently used in the field, meaning to produce light, especially in reference to the gain medium of a laser. Further use of the laser and maser in an extended sense, not referring to laser technology or devices, can be seen in usages such as astrophysical maser
10.
Knurling
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Knurling is a manufacturing process, typically conducted on a lathe, whereby a pattern of straight, angled or crossed lines is cut or rolled into the material. The operation is performed for producing indentations on a part of a workpiece, Knurling allows hands or fingers to get a better grip on the knurled object than would be provided by the originally smooth metal surface. Occasionally, the pattern is a series of straight ridges or a helix of straight ridges rather than the more-usual criss-cross pattern. Knurling may also be used as a method, because a rolled-in knurled surface has raised-up areas surrounding the depressed areas. As auto parts have become less expensive, knurling has become less prevalent than it once was, Knurling can also be used when a component will be assembled into a low precision component, for example a metal pin into a plastic molding. The outer surface of the pin is knurled so that the raised detail bites into the plastic irrespective of whether the size of the hole in the plastic closely matches the diameter of the pin. Tool handles, mechanical pencils, barbell bars, and the knobs on electronic equipment are frequently knurled. Knurling is also used on the grips of darts and the footpegs of BMX bicycles, aside from adding functionality to an object, knurling also adds a decorative pattern to the material. The knurled nut is one application, which uses a knurled finish instead of hexagonal or square edges which helps in tightening or loosening the nut without the use of a tool. The knurled surfaces provide enough grip to hold the nut between the thumb and forefinger, hence it is also called a thumb nut. It is mainly used on small diameter bolts, knurled nuts are typically used in electrical components, musical instruments and in automobiles. More common than knurl cutting, knurl rolling is usually accomplished using one or more very hard rollers that contain the reverse of the pattern to be imposed. It is possible for a straight knurl to be pressed with a roller, however the material needs to be supported adequately to avoid deformation. A criss-cross pattern can be accomplished using any of, A single roller that contains the reverse of the desired pattern. The integer number of knurls for any given diameter typically varies by three repetitions from the bottom to the top of the pattern. By comparison, for cut knurls, the spacing of the cuts is not preset and these resemble pipecutters but contain knurling wheels rather than cutting wheels. Usually, three wheels are carried by the tool, two left-handed wheels and one right-handed wheel or vice versa, Annular rings Frequently used when the mating part is plastic. Rings allow for easy mating but ridges make it difficult to pull the components apart, Linear knurl Used with mating plastic pieces, the Linear Knurl allows greater torsion between components
