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Pin (device)
A pin is a device, typically pointed, used for fastening objects or fabrics together. Pins can have the following sorts of body: *a shaft of a rigid inflexible material meant to be inserted in a slot, groove, or hole (as with pivots, hinges, and jigs) *a shaft connected to a head and ending in a sharp tip meant to pierce one or more pieces of soft materials like cloth or paper (the straight or push pin) *a single strip of a rigid but flexible material (e.g. a wire) whose length has been folded into parallel prongs in such fashion that the middle length of each curves towards the other so that, when anything is inserted between them, they act as a clamp (e.g. the bobby pin) * two strips of a rigid material bound together by a spring at one end so that, when the spring held open, one can insert some material between the prongs at the other end that, the spring allowed to close, then clamp the inserted material. According to their function, pins can be made of metals (e.g. steel, c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drawing Pin
A drawing pin (in British English) or thumb tack (in North American English), also called a push-pin, is a short, small pin or nail with a flat, broad head that can be pressed into place with pressure from the thumb, often used for hanging light articles on a wall or noticeboard. Thumb tacks made of brass, tin or iron may be referred to as brass tacks, brass pins, tin tacks or iron tacks, respectively. These terms are particularly used in the idiomatic expression ''to come'' (or ''get'') ''down to brass'' (or otherwise) ''tacks'', meaning to consider basic facts of a situation. History The drawing pin was invented in name and first mass-produced in what is now the United States in the mid/late 1750s; the earliest use of the term "drawing pin" is listed in the Oxford English Dictionary as 1812. It was said that the use of the newly invented drawing pin to attach notices to school house doors was making significant contribution to the whittling away of their gothic doors ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kurgan
A kurgan is a type of tumulus (burial mound) constructed over a grave, often characterized by containing a single human body along with grave vessels, weapons, and horses. Originally in use on the Pontic–Caspian steppe, kurgans spread into much of Central Asia and Eastern, Southeast, Western, and Northern Europe during the third millennium BC. The earliest kurgans date to the fourth millennium BC in the Caucasus, and some researchers associate these with the Indo-Europeans. Kurgans were built in the Eneolithic, Bronze, Iron, Antiquity, and Middle Ages, with ancient traditions still active in Southern Siberia and Central Asia. Etymology According to the Etymological dictionary of the Ukrainian language the word "kurhan" is borrowed directly from the Kipchak, part of the Turkic languages, and means: fortress, embankment, high grave. The word has two possible etymologies, either from the Old Turkic root ''qori-'' "to close, to block, to guard, to protect", or ''qur-'' " ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adam Smith
Adam Smith (baptised 1723 – 17 July 1790) was a Scottish economist and philosopher who was a pioneer in the field of political economy and key figure during the Scottish Enlightenment. Seen by some as the "father of economics"——— or the "father of capitalism".———— He is known for two classic works: ''The Theory of Moral Sentiments'' (1759) and ''The Wealth of Nations, An Inquiry into the Nature and Causes of the Wealth of Nations'' (1776). The latter, often abbreviated as ''The Wealth of Nations'', is regarded as his ''magnum opus'', marking the inception of modern economic scholarship as a comprehensive system and an academic discipline. Smith refuses to explain the distribution of wealth and power in terms of divine will and instead appeals to natural, political, social, economic, legal, environmental and technological factors, as well as the interactions among them. The work is notable for its contribution to economic theory, particularly in its exposition o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Division Of Labor
The division of labour is the separation of the tasks in any economic system or organisation so that participants may specialise (Departmentalization, specialisation). Individuals, organisations, and nations are endowed with or acquire specialised capabilities, and either form combinations or trade to take advantage of the capabilities of others in addition to their own. Specialised capabilities may include equipment or natural resources as well as skills. Training and combinations of equipment and other assets acting together are often important. For example, an individual may specialise by acquiring tools and the skills to use them effectively just as an organisation may specialise by acquiring specialised equipment and hiring or training skilled operators. The division of labour is the motive for trade and the source of economic interdependence. An increasing division of labour is associated with the growth of total Output (economics), output and trade, the rise of capitalis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Henri-Louis Duhamel Du Monceau
Henri-Louis Duhamel du Monceau (; 20 July 170013 August 1782) was a French physician, naval engineer and botanist. Biography Henri-Louis Duhamel du Monceau was born in Paris in 1700, the son of Alexandre Duhamel, lord of Denainvilliers. In his youth he developed a passion for botany, but at his father's wish he studied law from 1718 to 1721. After inheriting his father's large estate, he expanded it into a model farm, where he developed and tested new methods of horticulture, agriculture and forestry. The results of this work, he published in numerous publications. Commission by the French Academy of Sciences in 1728 Duhamel investigate the saffron cultivation in Gâtinais. In the following years continued to investigate physiological problems of crops. He also investigated growth of the trees in cooperation with Georges-Louis Leclerc de Buffon. From 1740 he also started focusing on meteorological problems, in particular their impact on agricultural production. In 1738 h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guild
A guild ( ) is an association of artisans and merchants who oversee the practice of their craft/trade in a particular territory. The earliest types of guild formed as organizations of tradespeople belonging to a professional association. They sometimes depended on grants of letters patent from a monarch or other ruler to enforce the flow of trade to their self-employed members, and to retain ownership of tools and the supply of materials, but most were regulated by the local government. Guild members found guilty of cheating the public would be fined or banned from the guild. A lasting legacy of traditional guilds are the guildhalls constructed and used as guild meeting-places. Typically the key "privilege" was that only guild members were allowed to sell their goods or practice their skill within the city. There might be controls on minimum or maximum prices, hours of trading, numbers of apprentices, and many other things. Critics argued that these rules reduced Free market, fre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pins And Mould - 15-17c - Museum Of Archaeology Of Moscow
A pin is a device, typically pointed, used for fastening objects or fabrics together. Pins can have the following sorts of body: *a shaft of a rigid inflexible material meant to be inserted in a slot, groove, or hole (as with pivots, hinges, and jigs) *a shaft connected to a head and ending in a sharp tip meant to pierce one or more pieces of soft materials like cloth or paper (the straight or push pin) *a single strip of a rigid but flexible material (e.g. a wire) whose length has been folded into parallel prongs in such fashion that the middle length of each curves towards the other so that, when anything is inserted between them, they act as a clamp (e.g. the bobby pin) * two strips of a rigid material bound together by a spring at one end so that, when the spring held open, one can insert some material between the prongs at the other end that, the spring allowed to close, then clamp the inserted material. According to their function, pins can be made of metals (e.g. steel, c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Titanium
Titanium is a chemical element; it has symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in sea water, aqua regia, and chlorine. Titanium was discovered in Cornwall, Great Britain, by William Gregor in 1791 and was named by Martin Heinrich Klaproth after the Titans of Greek mythology. The element occurs within a number of minerals, principally rutile and ilmenite, which are widely distributed in the Earth's crust and lithosphere; it is found in almost all living things, as well as bodies of water, rocks, and soils. The metal is extracted from its principal mineral ores by the Kroll and Hunter processes. The most common compound, titanium dioxide (TiO2), is a popular photocatalyst and is used in the manufacture of white pigments. Other compounds include titanium tetrachloride (TiCl4), a component of smoke screens and cata ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nickel
Nickel is a chemical element; it has symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive, but large pieces are slow to react with air under standard conditions because a passivation layer of nickel oxide forms on the surface that prevents further corrosion. Even so, pure native nickel is found in Earth's crust only in tiny amounts, usually in ultramafic rocks, and in the interiors of larger nickel–iron meteorites that were not exposed to oxygen when outside Earth's atmosphere. Meteoric nickel is found in combination with iron, a reflection of the origin of those elements as major end products of supernova nucleosynthesis. An iron–nickel mixture is thought to compose Earth's outer and inner cores. Use of nickel (as natural meteoric nickel–iron alloy) has been traced as far back as 3500 BCE. Nickel was first isolated and classifie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electroplating
Electroplating, also known as electrochemical deposition or electrodeposition, is a process for producing a metal coating on a solid substrate through the redox, reduction of cations of that metal by means of a direct current, direct electric current. The part to be coated acts as the cathode (negative electrode) of an electrolytic cell; the electrolyte is a solution (chemistry), solution of a salt (chemistry), salt whose cation is the metal to be coated, and the anode (positive electrode) is usually either a block of that metal, or of some inert electrical conductor, conductive material. The current is provided by an external power supply. Electroplating is widely used in industry and decorative arts to improve the surface qualities of objects—such as resistance to abrasion (mechanical), abrasion and corrosion, lubrication, lubricity, reflectivity, electrical conductivity, or appearance. It is used to build up thickness on undersized or worn-out parts and to manufacture metal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rust
Rust is an iron oxide, a usually reddish-brown oxide formed by the reaction of iron and oxygen in the catalytic presence of water or air moisture. Rust consists of hydrous iron(III) oxides (Fe2O3·nH2O) and iron(III) oxide-hydroxide (FeO(OH), Fe(OH)3), and is typically associated with the corrosion of refined iron. Given sufficient time, any iron mass, in the presence of water and oxygen, could eventually convert entirely to rust. Surface rust is commonly flaky and friable, and provides no passivational protection to the underlying iron unlike other metals such as aluminum, copper, and tin which form stable oxide layers. ''Rusting'' is the common term for corrosion of elemental iron and its alloys such as steel. Many other metals undergo similar corrosion, but the resulting oxides are not commonly called "rust". Several forms of rust are distinguishable both visually and by spectroscopy, and form under different circumstances. Other forms of rust include the result of r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ductile
Ductility refers to the ability of a material to sustain significant plastic deformation before fracture. Plastic deformation is the permanent distortion of a material under applied stress, as opposed to elastic deformation, which is reversible upon removing the stress. Ductility is a critical mechanical performance indicator, particularly in applications that require materials to bend, stretch, or deform in other ways without breaking. The extent of ductility can be quantitatively assessed using the percent elongation at break, given by the equation: \% \mathrm= \left ( \frac \right )\times100 where l_ is the length of the material after fracture and l_0 is the original length before testing. This formula helps in quantifying how much a material can stretch under tensile stress before failure, providing key insights into its ductile behavior. Ductility is an important consideration in engineering and manufacturing. It defines a material's suitability for certain manufactur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
