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Blade
A blade is the sharp, cutting portion of a tool, weapon, or machine, specifically designed to puncture, chop, slice, or scrape surfaces or materials. Blades are typically made from materials that are harder than those they are intended to cut. This includes early examples made from flaked stones like flint or obsidian, evolving through the ages into metal forms like copper, bronze, and iron, and culminating in modern versions made from steel or ceramics. Serving as one of humanity's oldest tools, blades continue to have wide-ranging applications, including in combat, cooking, and various other everyday and specialized tasks. Blades function by concentrating force at the cutting edge. Design variations, such as serrated edges found on bread knives and saws, serve to enhance this force concentration, adapting blades for specific functions and materials. Blades thus hold a significant place both historically and in contemporary society, reflecting an evolution in material tech ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ink Eraser
An ink eraser is an instrument used to scrape away or chemically bleach ink from a writing surface. This is a more involved process than removing pencil markings. Pencil marks can be gradually adhered to natural rubber fragments by rubbing the mark with a pencil eraser (this action is what prompted Joseph Priestly to give solidified latex its common name.) Ink, however readily penetrates the fibers of most papers and is therefore more difficult to extract by mechanical action. Older ink erasers are therefore small knives designed to scrape off the top few microns of a sheet of paper, removing the ink that had penetrated. In concert with bladed ink erasers an eraser similar to those at the end of pencils was also used, with additional abrasives, such as sand, mixed into the rubber. Fibreglass ink erasers also work by abrasion. These erasers physically remove the ink and the paper it has marked from the larger sheet. The chemical ink eradicator contains a substance that reacts wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yield (engineering)
In materials science and engineering, the yield point is the point on a stress-strain curve that indicates the limit of elastic behavior and the beginning of plastic behavior. Below the yield point, a material will deform elastically and will return to its original shape when the applied stress is removed. Once the yield point is passed, some fraction of the deformation will be permanent and non-reversible and is known as plastic deformation. The yield strength or yield stress is a material property and is the stress corresponding to the yield point at which the material begins to deform plastically. The yield strength is often used to determine the maximum allowable load in a mechanical component, since it represents the upper limit to forces that can be applied without producing permanent deformation. In some materials, such as aluminium, there is a gradual onset of non-linear behavior, making the precise yield point difficult to determine. In such a case, the offset yiel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elastic Modulus
An elastic modulus (also known as modulus of elasticity) is the unit of measurement of an object's or substance's resistance to being deformed elastically (i.e., non-permanently) when a stress is applied to it. The elastic modulus of an object is defined as the slope of its stress–strain curve in the elastic deformation region: A stiffer material will have a higher elastic modulus. An elastic modulus has the form: :\delta \ \stackrel\ \frac where stress is the force causing the deformation divided by the area to which the force is applied and strain is the ratio of the change in some parameter caused by the deformation to the original value of the parameter. Since strain is a dimensionless quantity, the units of \delta will be the same as the units of stress. Specifying how stress and strain are to be measured, including directions, allows for many types of elastic moduli to be defined. The three primary ones are: # ''Young's modulus'' (E) describes tensile and compressive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kitchen Knife
A kitchen knife is any knife that is intended to be used in food preparation. While much of this work can be accomplished with a few general-purpose knives – notably a large chef's knife, a tough cleaver, a small paring knife and some sort of serrated blade (such as a bread knife or serrated utility knife) – there are also many specialized knives that are designed for specific tasks. Kitchen knives can be made from several different materials. Construction Material * Carbon steel is an alloy of iron and carbon, often including other elements such as vanadium and manganese. Carbon steel commonly used in knives has around 1.0% carbon (ex. AISI 1095), is inexpensive, and holds its edge well. Carbon steel is normally easier to resharpen than many stainless steels, but is vulnerable to rust and stains. The blades should be cleaned, dried, and lubricated after each use. New carbon-steel knives may impart a metallic or "iron" flavour to acidic foods, though over time, the ste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rapier
A rapier () or is a type of sword with a slender and sharply-pointed two-edged blade that was popular in Western Europe, both for civilian use (dueling and self-defense) and as a military side arm, throughout the 16th and 17th centuries. Important sources for rapier fencing include the Italian Bolognese group, with early representatives such as Antonio Manciolino and Achille Marozzo publishing in the 1530s, and reaching the peak of its popularity with writers of the early 1600s (Salvator Fabris, Ridolfo Capo Ferro). In Spain, rapier fencing came to be known under the term of ("dexterity") in the second half of the 16th century, based on the theories of Jerónimo Sánchez de Carranza in his work ("The Philosophy of Arms and of their Dexterity and of Aggression and the Christian Defence"), published in 1569. The best known treatise of this tradition was published in French, by Girard Thibault, in 1630. The French small sword or court sword of the 18th century was a direct co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kukri
The kukri () or khukuri ( ne, खुकुरी, ) is a type of machete with a distinct recurve in its blade. It serves multiple purposes as a melee weapon and also as a regular cutting tool throughout most of South Asia. The ''kukri'', ''khukri'', and ''kukkri'' spellings are of Indian English origin, with the original Nepalese English spelling being ''khukuri''. Originating from the Indian subcontinent, the kukri is the national weapon of Nepal, traditionally serving the role of a basic utility knife for the Nepali-speaking Gurkhas, and consequently is a characteristic weapon of the Nepali Army. There have been, and still are many myths surrounding the kukri since its earliest recorded use in the 7th century—most notably that a traditional custom revolves around the blade in which it must draw blood, owing to its sole purpose as a fighting weapon, before being sheathed. However, they are frequently used as regular utility tools. History Researchers trace the origin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Falchion
A falchion (; Old French: ''fauchon''; Latin: ''falx'', "sickle") is a one-handed, single-edged sword of European origin. Falchions are found in different forms from around the 13th century up to and including the 16th century. In some versions, the falchion looks rather like the seax and later the sabre, and in other versions more like a machete with a crossguard. Types The blade designs of falchions varied widely across the continent and over time. They almost always included a single edge with a slight curve on the blade towards the point on the end and most were also affixed with a quilloned crossguard for the hilt in the manner of the contemporary arming swords. Unlike the double-edged swords of Europe, few actual swords of this type have survived to the present day; fewer than a dozen specimens are currently known. A number of weapons superficially similar to the falchion existed in Western Europe, including the Messer, hanger and the backsword. Two basic types of fa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Khopesh
The ''khopesh'' ('; also vocalized khepesh) is an Egyptian sickle-shaped sword that evolved from battle axes. Description A typical ''khopesh'' is 50–60 cm (20–24 inches) in length, though smaller examples also exist. The inside curve of the weapon could be used to trap an opponent's arm, or to pull an opponent's shield out of the way. These weapons changed from bronze to iron in the New Kingdom period. The earliest known depiction of a ''khopesh'' is from the Stele of the Vultures, depicting King Eannatum of Lagash wielding the weapon; this would date the ''khopesh'' to at least 2500 BC. The blade is only sharpened on the outside portion of the curved end. The ''khopesh'' evolved from the epsilon or similar crescent-shaped axes that were used in warfare. History The ''khopesh'' fell out of use around 1300 BC. However, on the 196 BC Rosetta Stone, it is referenced as the "sword" determinative in a hieroglyph block, with the spelled letters of k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Talwar
The talwar (), also spelled ''talwaar'' and ''tulwar'', is a type of curved sword or sabre from the Indian subcontinent. Etymology and classification The word ''talwar'' originated from the Sanskrit word ''taravāri'' ( sa, तरवारि) which means "one-edged sword". It is the word for ''sword'' in several related languages, such as Hindustani (Urdu and Hindi), Nepali, Marathi, Gujarati, Punjabi, etc. and as () in Bengali. Like many swords from around the world with an etymology derived from a term meaning simply 'sword', the talwar has in scholarship, and in museum and collector usage, acquired a more specific meaning. Unfortunately, South Asian swords, while showing a rich diversity of forms, suffer from relatively poor dating (so developmental history is obscure) and a lack of precise nomenclature and classification. The typical talwar is a type of sabre, characterised by a curved blade (without the radical curve of some Persian swords), possessing an all-metal hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whale Knife Hg
Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and porpoises. Dolphins and porpoises may be considered whales from a formal, cladistic perspective. Whales, dolphins and porpoises belong to the order Cetartiodactyla, which consists of even-toed ungulates. Their closest non-cetacean living relatives are the hippopotamuses, from which they and other cetaceans diverged about 54 million years ago. The two parvorders of whales, baleen whales (Mysticeti) and toothed whales (Odontoceti), are thought to have had their last common ancestor around 34 million years ago. Mysticetes include four extant (living) families: Balaenopteridae (the rorquals), Balaenidae (right whales), Cetotheriidae (the pygmy right whale), and Eschrichtiidae (the grey whale). Odontocetes include the Monodontidae (b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pressure
Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and even by industry. Further, both spellings are often used ''within'' a particular industry or country. Industries in British English-speaking countries typically use the "gauge" spelling. is the pressure relative to the ambient pressure. Various units are used to express pressure. Some of these derive from a unit of force divided by a unit of area; the SI unit of pressure, the pascal (Pa), for example, is one newton per square metre (N/m2); similarly, the pound-force per square inch (psi) is the traditional unit of pressure in the imperial and U.S. customary systems. Pressure may also be expressed in terms of standard atmospheric pressure; the atmosphere (atm) is equal to this pressure, and the torr is defined as of this. Manometric u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
