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Guardrail End Terminal
Traffic barriers (known in North America as guardrails or guard rails, in Britain as crash barriers, and in auto racing as Armco barriersAK Steel (formerly Armco) genericized trademark) keep vehicles within their roadway and prevent them from colliding with dangerous obstacles such as boulders, sign supports, trees, bridge abutments, buildings, walls, and large storm drains, or from traversing steep (non-recoverable) slopes or entering deep water. They are also installed within road median, medians of divided highways to prevent errant vehicles from entering the opposing carriageway of traffic and help to reduce head-on collisions. Some of these barriers, designed to be struck from either side, are called median barriers. Traffic barriers can also be used to protect vulnerable areas like school yards, pedestrian zones, and fuel tanks from errant vehicles. In pedestrian zones, like school yards, they also prevent children or other pedestrians from running onto the road. While barr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Power In The United States
In the United States, nuclear power is provided by 94 commercial reactors with a net capacity of 97 gigawatts (GW), with 63 pressurized water reactors and 31 boiling water reactors. In 2019, they produced a total of 809.41 terawatt-hours of electricity, and by 2024 nuclear energy accounted for 18.6% of the nation's total electric energy generation. In 2018, nuclear comprised nearly 50 percent of US emission-free energy generation. there were two new reactors under construction with a gross electrical capacity of 2,500 MW, while 39 reactors have been permanently shut down. The United States is the world's largest producer of commercial nuclear power, and in 2013 generated 33% of the world's nuclear electricity. With the past and future scheduled plant closings, China and Russia could surpass the United States in nuclear energy production. the Nuclear Regulatory Commission (NRC) had granted license renewals providing 20-year extensions to a total of 74 reactors. In early 2014 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bridge Pier
The pier of a bridge is an intermediate support that holds the deck of the structure. It is a massive and permanent support, as opposed to the shoring, which is lighter and provides temporary support. History Until the advent of concrete and the use of cast iron and then steel, bridges were made of masonry. Roman bridges were sturdy, semicircular, and rested on thick piers, with a width equal to about half the span of the vault. It was only from 1750, with Jean-Rodolphe Perronet, that the thickness of the piers could be reduced. While it was considered an absolute rule to give them a thickness equal to one-fifth of the span, Perronet proposed and succeeded in having thicknesses equal to one-tenth of the span and rises varying between one-fifth and one-seventh accepted. These reductions significantly reduced the obstacle to water flow created by the structure. With a height of 92 meters, the piers of the Fades viaduct in France, inaugurated on 10 October 1909, are the tallest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vehicle Rollover
A rollover or overturn is a type of vehicle crash in which a vehicle tips over onto its side or roof. Rollovers have a higher fatality rate than other types of vehicle collisions. Dynamics Vehicle rollovers are divided into two categories: tripped and untripped. Tripped rollovers are caused by forces from an external object, such as a curb or a collision with another vehicle. Untripped rollovers are the result of steering input, speed, and friction with the ground. Trailers that are not roll-coupled (i.e. those that use a trailer coupling rather than a fifth wheel) are more prone to rolling as they do not have the tractor unit or prime mover for additional stability. Untripped rollovers Untripped rollovers occur when cornering forces destabilize the vehicle. As a vehicle rounds a corner, three forces act on it: tire forces (the centripetal force), inertial effects (the centrifugal force), and gravity. The cornering forces from the tire push the vehicle towards the center of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Median Barrier
A Jersey barrier, Jersey wall, or Jersey bump is a modular concrete or plastic barrier employed to separate lanes of traffic. It is designed to minimize vehicle damage in cases of incidental contact while still preventing vehicle crossovers resulting in a likely head-on collision. Jersey barriers are also used to reroute traffic and protect pedestrians and workers during highway construction. They are named after the U.S. state of New Jersey which first started using the barriers as separators between lanes of a highway in the 1950s. The barriers are also known as a K-rail, a term stipulated in the California Department of Transportation specification for temporary concrete traffic barriers which first started using concrete median barriers in the mid-1940s. Over time, different variants were created. Taller variants, such as the Ontario Tall Wall, proved more effective at stopping vehicles and had the added advantage of blocking most oncoming headlights. More modular variant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Safety And Security
Nuclear safety is defined by the International Atomic Energy Agency (IAEA) as "The achievement of proper operating conditions, prevention of accidents or mitigation of accident consequences, resulting in protection of workers, the public and the environment from undue radiation hazards". The IAEA defines nuclear security as "The prevention and detection of and response to, theft, sabotage, unauthorized access, illegal transfer or other malicious acts involving nuclear materials, other radioactive substances or their associated facilities". This covers nuclear power plants and all other nuclear facilities, the transportation of nuclear materials, and the use and storage of nuclear materials for medical, power, industry, and military uses. The nuclear power industry has improved the safety and performance of reactors, and has proposed new and safer reactor designs. However, a perfect safety cannot be guaranteed. Potential sources of problems include human errors and external ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intrusion Detection System
An intrusion detection system (IDS) is a device or software application that monitors a network or systems for malicious activity or policy violations. Any intrusion activity or violation is typically either reported to an administrator or collected centrally using a security information and event management (SIEM) system. A SIEM system combines outputs from multiple sources and uses alarm filtering techniques to distinguish malicious activity from false alarms. IDS types range in scope from single computers to large networks. The most common classifications are network intrusion detection systems (NIDS) and host-based intrusion detection systems (HIDS). A system that monitors important operating system files is an example of an HIDS, while a system that analyzes incoming network traffic is an example of an NIDS. It is also possible to classify IDS by detection approach. The most well-known variants are signature-based detection (recognizing bad patterns, such as exploitatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Access Control
In physical security and information security, access control (AC) is the action of deciding whether a subject should be granted or denied access to an object (for example, a place or a resource). The act of ''accessing'' may mean consuming, entering, or using. It is often used interchangeably with authorization, although the authorization may be granted well in advance of the access control decision. Access control on digital platforms is also termed admission control. The protection of external databases is essential to preserve digital security. Access control is considered to be a significant aspect of privacy that should be further studied. Access control policy (also access policy) is part of an organization’s security policy. In order to verify the access control policy, organizations use an access control model. General security policies require designing or selecting appropriate security controls to satisfy an organization's risk appetite - access policies ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surveillance
Surveillance is the monitoring of behavior, many activities, or information for the purpose of information gathering, influencing, managing, or directing. This can include observation from a distance by means of electronic equipment, such as closed-circuit television (CCTV), or interception of electronically transmitted information like Internet traffic. Increasingly, Government, governments may also obtain Customer data, consumer data through the purchase of online information, effectively expanding surveillance capabilities through commercially available digital records. It can also include simple technical methods, such as Human intelligence (intelligence gathering), human intelligence gathering and postal interception. Surveillance is used by citizens, for instance for protecting their neighborhoods. It is widely used by governments for intelligence gathering, including espionage, prevention of crime, the protection of a process, person, group or object, or the investigat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Power Plant
A nuclear power plant (NPP), also known as a nuclear power station (NPS), nuclear generating station (NGS) or atomic power station (APS) is a thermal power station in which the heat source is a nuclear reactor. As is typical of thermal power stations, heat is used to generate steam that drives a steam turbine connected to a electric generator, generator that produces electricity. , the International Atomic Energy Agency reported that there were 410 nuclear power reactors in operation in 32 countries around the world, and 57 nuclear power reactors under construction. Most nuclear power plants use thermal reactors with enriched uranium in a Nuclear fuel cycle#Once-through nuclear fuel cycle, once-through fuel cycle. Fuel is removed when the percentage of neutron poison, neutron absorbing atoms becomes so large that a nuclear chain reaction, chain reaction can no longer be sustained, typically three years. It is then cooled for several years in on-site spent fuel pools be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Explosive Device
An explosive device is a device that relies on the exothermic reaction of an explosive material to provide a violent release of energy. Applications of explosive devices include: *Building implosion (demolition) * Excavation *Explosive forming * Explosive welding *Mining of minerals *Murder **Assassination *Riot control *Terrorism *War Types of explosive devices include: * Explosive weapon **Anti-personnel mine **Artillery shells **Bomb **Grenade **Improvised explosive device **Land mine ** Nuclear explosive device **Unexploded ordnance **Naval mine *Car bomb *Letter bomb *Stun grenade *Smoke grenade * Flashbang grenade *Some pyrotechnics **Fireworks Fireworks are Explosive, low explosive Pyrotechnics, pyrotechnic devices used for aesthetic and entertainment purposes. They are most commonly used in fireworks displays (also called a fireworks show or pyrotechnics), combining a large numbe ... * Explosively pumped flux compression generator * Explosive-driven ferroelectric ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Land 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 vehicles (e.g. bicycles, tricycles, velomobiles), animal-powered transports (e.g. horse-drawn carriages/wagons, ox carts, dog sleds), motor vehicles (e.g. motorcycles, cars, trucks, buses, mobility scooters) and railed vehicles (trains, trams and monorails), but more broadly also includes cable transport ( cable cars and elevators), watercraft (ships, boats and underwater vehicles), amphibious vehicles (e.g. screw-propelled vehicles, hovercraft, seaplanes), aircraft (airplanes, helicopters, 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 the ground: wheels, tracks, rails or skis, as well as the non-contact technolog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
