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Sledgehammers
A sledgehammer is a tool with a large, flat, often metal head, attached to a long handle. The long handle combined with a heavy head allows the sledgehammer to gather momentum during a swing and apply a large force compared to hammers designed to drive nails. Along with the mallet, it shares the ability to distribute force over a wide area. This is in contrast to other types of hammers, which concentrate force in a relatively small area. Etymology The word sledgehammer is derived from the Anglo Saxon "''slægan''", which, in its first sense, means "to strike violently". The English words "slag", "slay", and "slog" are cognates. Uses The handle can range from to a full long, depending on the mass of the head. The head mass is usually . Modern heavy duty sledgehammers come with heads. Sledgehammers usually require two hands and a swinging motion involving the entire torso, in contrast to smaller hammers used for driving in nails. The combination of a long swinging range, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hammer Straight Pane Sledge
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, co ... [...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, c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hand Tool
A hand tool is any tool that is powered by hand rather than a motor. Categories of hand tools include wrenches, pliers, cutters, files, striking tools, struck or hammered tools, screwdrivers, vises, clamps, snips, hacksaws, drills, and knives. Outdoor tools such as garden forks, pruning shears, and rakes are additional forms of hand tools. Portable power tools are not hand tools. History Hand tools have been used by humans since the Stone Age when stones were used for hammering and cutting. During the Bronze Age tools were made by casting the copper and tin alloys. Bronze tools were sharper and harder than those made of stone. During the Iron Age iron replaced bronze, and tools became even stronger and more durable. The Romans developed tools during this period which are similar to those being produced today. In the period since the industrial revolution, the manufacture of tools has transitioned from being craftsman made to being factory produced. A large collection of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wall
A wall is a structure and a surface that defines an area; carries a load; provides security, shelter, or soundproofing; or, is decorative. There are many kinds of walls, including: * Walls in buildings that form a fundamental part of the superstructure or separate interior rooms, sometimes for fire safety *Glass walls (a wall in which the primary structure is made of glass; does not include openings within walls that have glass coverings: these are windows) * Border barriers between countries * Brick walls * Defensive walls in fortifications * Permanent, solid fences * Retaining walls, which hold back dirt, stone, water, or noise sound * Stone walls * Walls that protect from oceans (seawalls) or rivers (levees) Etymology The term ''wall'' comes from Latin ''vallum'' meaning "...an earthen wall or rampart set with palisades, a row or line of stakes, a wall, a rampart, fortification..." while the Latin word ''murus'' means a defensive stone wall. English uses the same wor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Golden Spike
The golden spike (also known as The Last Spike) is the ceremonial 17.6-karat gold final spike driven by Leland Stanford to join the rails of the first transcontinental railroad across the United States connecting the Central Pacific Railroad from Sacramento and the Union Pacific Railroad from Omaha on May 10, 1869, at Promontory Summit, Utah Territory. The term ''last spike'' has been used to refer to one driven at the usually ceremonial completion of any new railroad construction projects, particularly those in which construction is undertaken from two disparate origins towards a common meeting point. The spike is now displayed in the Cantor Arts Center at Stanford University. History Completing the last link in the transcontinental railroad with a spike of gold was the brainchild of David Hewes, a San Francisco financier and contractor.Bowman, J.N"Driving the Last Spike at Promontory, 1869" ''California Historical Society Quarterly'', Vol. XXXVI, No. 2, June 1957, pp. 9 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leland Stanford
Amasa Leland Stanford (March 9, 1824June 21, 1893) was an American industrialist and politician. A member of the Republican Party, he served as the 8th governor of California from 1862 to 1863 and represented California in the United States Senate from 1885 until his death in 1893. He and his wife Jane were also the founders of Stanford University, which they named after their late son. Prior to his political career, Stanford was a successful merchant and wholesaler who built his business empire after migrating to California during the Gold Rush. As president of the Central Pacific Railroad and later the Southern Pacific from 1885 to 1890, he held tremendous power in the region and a lasting impact on California. Early life and career Leland Stanford was born in 1824 in what was then Watervliet, New York (now the Town of Colonie). He was one of eight children of Josiah and Elizabeth Phillips Stanford. Among his siblings were New York State Senator Charles Stanford (1819– ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Promontory, Utah
Promontory is an area of high ground in Box Elder County, Utah, United States, 32 mi (51 km) west of Brigham City and 66 mi (106 km) northwest of Salt Lake City. Rising to an elevation of 4,902 feet (1,494 m) above sea level, it lies to the north of the Promontory Mountains and the Great Salt Lake. It is notable as the location of Promontory Summit, where the First transcontinental railroad from Sacramento to Omaha in the United States was officially completed on May 10, 1869. The location is sometimes confused with Promontory Point, a location further south along the southern tip of the Promontory Mountains. Both locations are significant to the Overland Route; Promontory Summit is where the original, abandoned alignment crossed the Promontory Mountains while the modern alignment, called the Lucin Cutoff, crosses the mountains at Promontory Point. By the summer of 1868, the Central Pacific (CP) had completed the first rail route through the Sierra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Union Pacific
The Union Pacific Railroad , legally Union Pacific Railroad Company and often called simply Union Pacific, is a freight-hauling railroad that operates 8,300 locomotives over routes in 23 U.S. states west of Chicago and New Orleans. Union Pacific is the second largest railroad in the United States after BNSF, with which it shares a duopoly on transcontinental freight rail lines in the Western, Midwestern and Southern United States. Founded in 1862, the original Union Pacific Rail Road was part of the first transcontinental railroad project, later known as the Overland Route. Over the next century, UP absorbed the Missouri Pacific Railroad, the Chicago and North Western Transportation Company, the Western Pacific Railroad, the Missouri–Kansas–Texas Railroad and the Chicago, Rock Island and Pacific Railroad. In 1996, the Union Pacific merged with Southern Pacific Transportation Company, itself a giant system that was absorbed by the Denver and Rio Grande Western Railroad. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Railroad Tie
A railroad tie, crosstie (American English), railway tie (Canadian English) or railway sleeper (Australian and British English) is a rectangular support for the rails in railroad tracks. Generally laid perpendicular to the rails, ties transfer loads to the track ballast and subgrade, hold the rails upright and keep them spaced to the correct gauge. Railroad ties are traditionally made of wood, but prestressed concrete is now also widely used, especially in Europe and Asia. Steel ties are common on secondary lines in the UK; plastic composite ties are also employed, although far less than wood or concrete. As of January 2008, the approximate market share in North America for traditional and wood ties was 91.5%, the remainder being concrete, steel, azobé (red ironwood) and plastic composite. Tie spacing may depend on the type of tie, traffic loads and other requirements, for example 2640 concrete ties per mile on North American mainline railroads to 2112 timber ties per mile ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Counter Terrorist
Counterterrorism (also spelled counter-terrorism), also known as anti-terrorism, incorporates the practices, military tactics, techniques, and strategies that governments, law enforcement, business, and intelligence agencies use to combat or eliminate terrorism. Counterterrorism strategies are a government's motivation to use the instruments of national power to defeat terrorists, the organizations they maintain, and the networks they contain. If definitions of terrorism are part of a broader insurgency, counterterrorism may employ counterinsurgency measures. The United States Armed Forces uses the term foreign internal defense for programs that support other countries' attempts to suppress insurgency, lawlessness, or subversion, or to reduce the conditions under which threats to national security may develop. History The first counter-terrorism body formed was the Special Irish Branch of the Metropolitan Police, later renamed the Special Branch after it expanded its scope b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Special Air Service
The Special Air Service (SAS) is a special forces unit of the British Army. It was founded as a regiment in 1941 by David Stirling and in 1950, it was reconstituted as a corps. The unit specialises in a number of roles including counter-terrorism, hostage rescue, direct action and covert reconnaissance. Much of the information about the SAS is highly classified, and the unit is not commented on by either the British government or the Ministry of Defence due to the secrecy and sensitivity of its operations. The corps currently consists of the 22 Special Air Service Regiment, the regular component, as well as the 21 Special Air Service Regiment (Artists) (Reserve) and the 23 Special Air Service Regiment (Reserve), which are reserve units, all under the operational command of United Kingdom Special Forces (UKSF). Its sister unit is the Royal Navy's Special Boat Service which specialises in maritime counter-terrorism. Both units are under the operational control of the Directo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
