|
Metal-work
Metalworking is the process of shaping and reshaping metals to create useful objects, parts, assemblies, and large scale structures. As a term it covers a wide and diverse range of processes, skills, and tools for producing objects on every scale: from huge ships, buildings, and bridges down to precise engine parts and delicate jewelry. The historical roots of metalworking predate recorded history; its use spans cultures, civilizations and millennia. It has evolved from shaping soft, native metals like gold with simple hand tools, through the smelting of ores and hot forging of harder metals like iron, up to highly technical modern processes such as machining and welding. It has been used as an industry, a driver of trade, individual hobbies, and in the creation of art; it can be regarded as both a science and a craft. Modern metalworking processes, though diverse and specialized, can be categorized into one of three broad areas known as forming, cutting, or joining processes. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dreher An Einer Drehbank , a cycling team that used the name Dreher from 1970 to 1972
{{Disambiguation ...
Dreher may refer to: * Dreher (surname) * Dreher Brewery, brewery in Budapest, Hungary * Dreher Township, Wayne County, Pennsylvania, township in Pennsylvania * Bridge in Dreher Township, bridge in Dreher Township, Wayne County, Pennsylvania * Dreher Island State Recreation Area, park in South Carolina * Dreher High School, high school in Columbia, South Carolina * Jacob Wingard Dreher House, historic home in Lexington County, South Carolina * Dreher Shoals Dam, dam in Lexington County, South Carolina See also * Brooklyn (cycling team) Brooklyn was an Italian professional cycling team that existed from 1970 to 1977. It was a mainly a one-day classics team and featured riders such as Roger De Vlaeminck, who won Paris–Roubaix Paris–Roubaix is a one-day professional road b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mining
Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the economic viability of investing in the equipment, labor, and energy required to extract, refine and transport the materials found at the mine to manufacturers who can use the material. Ores recovered by mining include metals, coal, oil shale, gemstones, limestone, chalk, dimension stone, rock salt, potash, gravel, and clay. Mining is required to obtain most materials that cannot be grown through agricultural processes, or feasibly created artificially in a laboratory or factory. Mining in a wider sense includes extraction of any non-renewable resource such as petroleum, natural gas, or even water. Modern mining processes involve prospecting for ore bodies, analysis of the profit potential of a proposed mine, extraction of the desi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Malleability
Ductility is a mechanical property commonly described as a material's amenability to drawing (e.g. into wire). In materials science, ductility is defined by the degree to which a material can sustain plastic deformation under tensile stress before failure. Ductility is an important consideration in engineering and manufacturing. It defines a material's suitability for certain manufacturing operations (such as cold working) and its capacity to absorb mechanical overload.. Some metals that are generally described as ductile include gold and copper. However, not all metals experience ductile failure as some can be characterized with brittle failure like cast iron. Polymers generally can be viewed as ductile materials as they typically allow for plastic deformation. Malleability, a similar mechanical property, is characterized by a material's ability to deform plastically without failure under compressive stress. Historically, materials were considered malleable if they were am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anvil
An anvil is a metalworking tool consisting of a large block of metal (usually forged or cast steel), with a flattened top surface, upon which another object is struck (or "worked"). Anvils are as massive as practical, because the higher their inertia, the more efficiently they cause the energy of striking tools to be transferred to the work piece. In most cases the anvil is used as a forging tool. Before the advent of modern welding technology, it was the primary tool of metal workers. The great majority of modern anvils are made of cast steel that has been heat treated by either flame or electric induction. Inexpensive anvils have been made of cast iron and low quality steel, but are considered unsuitable for serious use as they deform and lack rebound when struck. Structure The primary work surface of the anvil is known as the face. It is generally made of hardened steel and should be flat and smooth with rounded edges for most work. Any marks on the face w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hammer
A hammer is a tool, most often a hand tool, consisting of a weighted "head" fixed to a long handle that is swung to deliver an impact to a small area of an object. This can be, for example, to drive nails into wood, to shape metal (as with a forge), or to crush rock. Hammers are used for a wide range of driving, shaping, breaking and non-destructive striking applications. Traditional disciplines include carpentry, blacksmithing, warfare, and percussive musicianship (as with a gong). Hammering is use of a hammer in its strike capacity, as opposed to prying with a secondary claw or grappling with a secondary hook. Carpentry and blacksmithing hammers are generally wielded from a stationary stance against a stationary target as gripped and propelled with one arm, in a lengthy downward planar arc—downward to add kinetic energy to the impact—pivoting mainly around the shoulder and elbow, with a small but brisk wrist rotation shortly before impact; for extreme impact ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rock (geology)
In geology, rock (or stone) is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its chemical composition, and the way in which it is formed. Rocks form the Earth's outer solid layer, the crust, and most of its interior, except for the liquid outer core and pockets of magma in the asthenosphere. The study of rocks involves multiple subdisciplines of geology, including petrology and mineralogy. It may be limited to rocks found on Earth, or it may include planetary geology that studies the rocks of other celestial objects. Rocks are usually grouped into three main groups: igneous rocks, sedimentary rocks and metamorphic rocks. Igneous rocks are formed when magma cools in the Earth's crust, or lava cools on the ground surface or the seabed. Sedimentary rocks are formed by diagenesis and lithification of sediments, which in turn are formed by the weathering, transport, and deposition of exi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meteor
A meteoroid () is a small rocky or metallic body in outer space. Meteoroids are defined as objects significantly smaller than asteroids, ranging in size from grains to objects up to a meter wide. Objects smaller than this are classified as micrometeoroids or space dust. Most are fragments from comets or asteroids, whereas others are collision impact debris ejected from bodies such as the Moon or Mars. When a meteoroid, comet, or asteroid enters Earth's atmosphere at a speed typically in excess of , aerodynamic heating of that object produces a streak of light, both from the glowing object and the trail of glowing particles that it leaves in its wake. This phenomenon is called a meteor or "shooting star". Meteors typically become visible when they are about 100 km above sea level. A series of many meteors appearing seconds or minutes apart and appearing to originate from the same fixed point in the sky is called a meteor shower. A meteorite is the remains of a met ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemistry
Chemistry is the scientific study of the properties and behavior of matter. It is a natural science that covers the elements that make up matter to the compounds made of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during a reaction with other substances. Chemistry also addresses the nature of chemical bonds in chemical compounds. In the scope of its subject, chemistry occupies an intermediate position between physics and biology. It is sometimes called the central science because it provides a foundation for understanding both basic and applied scientific disciplines at a fundamental level. For example, chemistry explains aspects of plant growth ( botany), the formation of igneous rocks ( geology), how atmospheric ozone is formed and how environmental pollutants are degraded ( ecology), the properties of the soil on the moon ( cosmochemistry), how medications work ( pharmacology), and how to collec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isaac Asimov
yi, יצחק אזימאװ , birth_date = , birth_place = Petrovichi, Russian SFSR , spouse = , relatives = , children = 2 , death_date = , death_place = Manhattan, New York City, U.S. , nationality = Russian (1920–1922)Soviet (1922–1928)American (1928–1992) , occupation = Writer, professor of biochemistry , years_active = 1939–1992 , genre = Science fiction ( hard SF, social SF), mystery, popular science , subject = Popular science, science textbooks, essays, history, literary criticism , education = Columbia University ( BA, MA, PhD) , movement = Golden Age of Science Fiction , module = , signature = Isaac Asimov signature.svg Isaac Asimov ( ; 1920 – April 6, 1992) was an American writer and professor of biochemistry at Boston University. During his lifetime, Asimov was considered one of the "Big Three" science fiction writers, along with Robert A. Heinlein and Arthur C. Clarke. A prolific writer, he wrote or edited more than 500 book ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Varna Necropolis
The Varna Necropolis ( bg, Варненски некропол), or Varna Cemetery, is a burial site in the western industrial zone of Varna (approximately half a kilometre from Lake Varna and 4 km from the city centre), internationally considered one of the key archaeological sites in world prehistory. The oldest gold treasure and jewelry in the world, dating from 4,600 BC to 4,200 BC, was discovered at the site. Several prehistoric Bulgarian finds are considered no less old – the golden treasures of Hotnitsa, Durankulak, artifacts from the Kurgan settlement of Yunatsite near Pazardzhik, the golden treasure Sakar, as well as beads and gold jewelry found in the Kurgan settlement of Provadia – Solnitsata (“salt pit”). However, Varna gold is most often called the oldest since this treasure is the largest and most diverse. Discovery and excavation The site was accidentally discovered in October 1972 by excavator operator Raycho Marinov. The first to value the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Michigan
Lake Michigan is one of the five Great Lakes of North America. It is the second-largest of the Great Lakes by volume () and the third-largest by surface area (), after Lake Superior and Lake Huron. To the east, its basin is conjoined with that of Lake Huron through the wide, deep, Straits of Mackinac, giving it the same surface elevation as its easterly counterpart; the two are technically a single lake. Lake Michigan is the world's largest lake by area in one country. Located in the United States, it is shared, from west to east, by the states of Wisconsin, Illinois, Indiana, and Michigan. Ports along its shores include Milwaukee and the City of Green Bay in Wisconsin; Chicago in Illinois; Gary in Indiana; and Muskegon in Michigan. Green Bay is a large bay in its northwest, and Grand Traverse Bay is in the northeast. The word "Michigan" is believed to come from the Ojibwe word (''michi-gami'' or ''mishigami'') meaning "great water". History Some of most studied ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wisconsin
Wisconsin () is a state in the upper Midwestern United States. Wisconsin is the 25th-largest state by total area and the 20th-most populous. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michigan to the northeast, and Lake Superior to the north. The bulk of Wisconsin's population live in areas situated along the shores of Lake Michigan. The largest city, Milwaukee, anchors its largest metropolitan area, followed by Green Bay and Kenosha, the third- and fourth-most-populated Wisconsin cities respectively. The state capital, Madison, is currently the second-most-populated and fastest-growing city in the state. Wisconsin is divided into 72 counties and as of the 2020 census had a population of nearly 5.9 million. Wisconsin's geography is diverse, having been greatly impacted by glaciers during the Ice Age with the exception of the Driftless Area. The Northern Highland and Western Upland along ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
