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Berms
A berm is a level space, shelf, or raised barrier (usually made of Soil compaction, compacted soil) separating areas in a vertical way, especially partway up a long slope. It can serve as a terrace road, track, path, a fortification line, a border wall, border/separation barrier for navigation, good drainage, industry, or other purposes. Etymology The word is from Middle Dutch and came into usage in English via French. Military use History In medieval military engineering, a berm (or berme) was a level space between a parapet or defensive wall and an adjacent steep-walled ditch (fortification), ditch or moat. It was intended to reduce soil pressure on the walls of the excavated part to prevent its collapse. It also meant that debris dislodged from fortifications would not fall into (and fill) a ditch or moat. In the trench warfare of World War I, the name was applied to a similar feature at the lip of a trench, which served mainly as an elbow-rest for riflemen. Modern u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trench
A trench is a type of digging, excavation or depression in the ground that is generally deeper than it is wide (as opposed to a swale (landform), swale or a bar ditch), and narrow compared with its length (as opposed to a simple hole or trapping pit, pit). In geology, trenches result from erosion by rivers or by geological movement of tectonic plates. In civil engineering, trenches are often created to install underground utilities such as Pipeline transport, gas, Water distribution system, water, Underground power lines, power and Undergrounding, communication lines. In construction, trenches are dug for foundations of buildings, retaining walls and dams, and for Tunnel construction#Cut-and-cover, cut-and-cover construction of tunnels. In archaeology, the "trench method" is used for searching and Excavation (archaeology), excavating ancient ruins or to dig into stratum, strata of sedimented material. In geotechnical engineering, trench investigations locate faults and investigat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Velocity
Velocity is a measurement of speed in a certain direction of motion. It is a fundamental concept in kinematics, the branch of classical mechanics that describes the motion of physical objects. Velocity is a vector (geometry), vector Physical quantity, quantity, meaning that both magnitude and direction are needed to define it. The Scalar (physics), scalar absolute value (Magnitude (mathematics), magnitude) of velocity is called , being a coherent derived unit whose quantity is measured in the International System of Units, SI (metric system) as metres per second (m/s or m⋅s−1). For example, "5 metres per second" is a scalar, whereas "5 metres per second east" is a vector. If there is a change in speed, direction or both, then the object is said to be undergoing an ''acceleration''. Definition Average velocity The average velocity of an object over a period of time is its Displacement (geometry), change in position, \Delta s, divided by the duration of the period, \Delt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Runoff
Surface runoff (also known as overland flow or terrestrial runoff) is the unconfined flow of water over the ground surface, in contrast to ''channel runoff'' (or ''stream flow''). It occurs when excess rainwater, stormwater, meltwater, or other sources, can no longer sufficiently rapidly infiltrate in the soil. This can occur when the soil is #Saturation excess overland flow, saturated by water to its full capacity, and the rain arrives #Infiltration excess overland flow, more quickly than the soil can absorb it. Surface runoff often occurs because wikt:impervious#Adjective, impervious areas (such as roofs and Road surface, pavement) do not allow water to soak into the ground. Furthermore, runoff can occur either through natural or human-made processes. Surface runoff is a major component of the water cycle. It is the primary agent of Soil erosion#Rainfall and runoff, soil erosion by water. The land area producing runoff that drains to a common point is called a drainage basin. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sediment
Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand and silt can be carried in suspension (chemistry), suspension in river water and on reaching the sea bed deposited by sedimentation; if buried, they may eventually become sandstone and siltstone (sedimentary rocks) through lithification. Sediments are most often transported by water (fluvial, fluvial processes), but also wind (aeolian processes) and glaciers. Beach sands and stream channel, river channel deposits are examples of fluvial transport and deposition (geology), deposition, though sediment also often settles out of slow-moving or standing water in lakes and oceans. Desert sand dunes and loess are examples of aeolian transport and deposition. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erosion
Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust and then sediment transport, transports it to another location where it is deposit (geology), deposited. Erosion is distinct from weathering which involves no movement. Removal of rock or soil as clastic sediment is referred to as ''physical'' or ''mechanical'' erosion; this contrasts with ''chemical'' erosion, where soil or rock material is removed from an area by Solvation, dissolution. Eroded sediment or solutes may be transported just a few millimetres, or for thousands of kilometres. Agents of erosion include rainfall; bedrock wear in rivers; coastal erosion by the sea and Wind wave, waves; glacier, glacial Plucking (glaciation), plucking, Abrasion (geology), abrasion, and scour; areal flooding; Aeolian processes, wind abrasion; groundwater processes; and Mass wastin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moroccan Western Sahara Wall
The Moroccan Western Sahara Wall or the Berm, also called the Moroccan sand wall (), is an approximately berm running south to north through Western Sahara and the southwestern portion of Morocco. It separates the Moroccan-controlled areas (the Southern Provinces) on the west from the Polisario-controlled areas ( Free Zone, nominally Sahrawi Arab Democratic Republic) on the east. The main function of the barriers is to exclude guerrilla fighters of the Polisario Front, who have sought Western Saharan independence since before Spain ended its colonial occupation in 1975, from the Moroccan-controlled western part of the territory. According to maps from the United Nations Mission for the Referendum in Western Sahara (MINURSO) or the United Nations High Commissioner for Refugees (UNHCR), in many places the wall extends several kilometers into internationally recognized Mauritanian territory. Names The wall is also called the Western Sahara berm and the Western Sahara separa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Construction
Construction are processes involved in delivering buildings, infrastructure, industrial facilities, and associated activities through to the end of their life. It typically starts with planning, financing, and design that continues until the asset is built and ready for use. Construction also covers repairs and maintenance work, any works to expand, extend and improve the asset, and its eventual demolition, dismantling or wikt:decommission, decommissioning. The construction industry contributes significantly to many countries' gross domestic products (Gross domestic product, GDP). Global expenditure on construction activities was about $4 trillion in 2012. In 2022, expenditure on the construction industry exceeded $11 trillion a year, equivalent to about 13 percent of global Gross domestic product, GDP. This spending was forecasted to rise to around $14.8 trillion in 2030. The construction industry promotes economic development and brings many non-monetary benefits to many cou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infantry
Infantry, or infantryman are a type of soldier who specialize in ground combat, typically fighting dismounted. Historically the term was used to describe foot soldiers, i.e. those who march and fight on foot. In modern usage, the term broadly encompasses a wide variety of subspecialties, including light infantry, irregular infantry, heavy infantry, mountain infantry, motorized infantry, mechanized infantry, Airborne forces, airborne infantry, Air assault, air assault infantry, and Marines, naval infantry. Other subtypes of infantry, such as line infantry and mounted infantry, were once commonplace but fell out of favor in the 1800s with the invention of more accurate and powerful weapons. Etymology and terminology In English, use of the term ''infantry'' began about the 1570s, describing soldiers who march and fight on foot. The word derives from Middle French , from older Italian (also Spanish) ''infanteria'' (foot soldiers too inexperienced for cavalry), from Latin '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Armoured Fighting Vehicle
An armoured fighting vehicle (British English) or armored fighting vehicle (American English) (AFV) is an armed combat vehicle protected by vehicle armour, armour, generally combining operational mobility with Offensive (military), offensive and defense (military), defensive capabilities. AFVs can be wheeled or Continuous track, tracked. Examples of AFVs are tanks, armored car (military), armoured cars, assault guns, Self-propelled artillery, self-propelled artilleries, infantry fighting vehicles (IFV), and armoured personnel carriers (APC). Armoured fighting vehicles are classified according to their characteristics and intended role on the battlefield. The classifications are not absolute; two countries may classify the same vehicle differently, and the criteria change over time. For example, relatively lightly armed armoured personnel carriers were largely superseded by infantry fighting vehicles with much heavier armament in a similar role. Successful designs are often ada ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vehicle
A vehicle () is a machine designed for self-propulsion, usually to transport people, cargo, or both. The term "vehicle" typically refers to land vehicles such as human-powered land vehicle, human-powered vehicles (e.g. bicycles, tricycles, velomobiles), animal-powered transports (e.g. horse-drawn vehicle, horse-drawn carriages/wagons, ox carts, dog sleds), motor vehicles (e.g. motorcycles, cars, trucks, buses, mobility scooters) and rail transport, railed vehicles (trains, trams and monorails), but more broadly also includes cable transport (aerial lift, cable cars and elevators), watercraft (ships, boats and underwater vehicles), amphibious vehicles (e.g. screw-propelled vehicles, hovercraft, seaplanes), aircraft (airplanes, helicopters, glider (aircraft), gliders and aerostats) and space vehicles (spacecraft, spaceplanes and launch vehicles). This article primarily concerns the more ubiquitous land vehicles, which can be broadly classified by the type of contact interface with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Military Engineering Vehicle
A military engineering vehicle is a vehicle built for construction work or for the transportation of combat engineering, combat engineers on the battlefield. These vehicles may be modified civilian equipment (such as the Armored bulldozer, armoured bulldozers that many nations field) or purpose-built military vehicles (such as the AVRE). The first appearance of such vehicles coincided with the appearance of the first tanks, these vehicles were modified Mark I tank, Mark V tanks for bridging and mine clearance. Modern ''military engineering vehicles'' are expected to fulfill numerous roles such as; bulldozer, crane (machine), crane, grader, excavator, dump truck, breaching vehicle, bridging vehicle, military ferry, amphibious crossing vehicle, and combat engineer section carrier. History World War One A Heavy RE tank was developed shortly after World War I by Major Giffard LeQuesne Martel RE. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
