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SAVIAC
The Shock and Vibration Information Analysis Center (SAVIAC) is a U.S. Government organization established by the U.S. Navy Office of Naval Research on 20 December 1946. SAVIAC's purpose is to promulgate information on the transient and vibratory response of structures and materials. This broad field includes such technical areas as the testing, analysis and design of structural or mechanical systems subjected to dynamic conditions and loading such as vibration, blast, impact, and shock for various agencies in the U. S. Government including NASA, the Department of Energy (DOE), and the Department of Defense (DOD). The organization sponsored the professional journal ''Shock and Vibration Journal'' and currently sponsors and publishes the professional journal ''Journal of Critical Technology in Shock and Vibration.'' SAVIAC also sponsored and published a series of monograms addressing different aspects of shock and vibration. In 2012 SAVIAC became inactive as a result of new Depart ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vibration
Vibration () is a mechanical phenomenon whereby oscillations occur about an equilibrium point. Vibration may be deterministic if the oscillations can be characterised precisely (e.g. the periodic motion of a pendulum), or random if the oscillations can only be analysed statistically (e.g. the movement of a tire on a gravel road). Vibration can be desirable: for example, the motion of a tuning fork, the reed in a woodwind instrument or harmonica, a mobile phone, or the cone of a loudspeaker. In many cases, however, vibration is undesirable, wasting energy and creating unwanted sound. For example, the vibrational motions of engines, electric motor An electric motor is a machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor's magnetic field and electric current in a electromagnetic coil, wire winding to gene ...s, or any Machine, mechanical device in operation are typically unwanted. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Federal Government Of The United States
The Federal Government of the United States of America (U.S. federal government or U.S. government) is the Federation#Federal governments, national government of the United States. The U.S. federal government is composed of three distinct branches: United States Congress, legislative, President of the United States, executive, and Federal judiciary of the United States, judicial. Powers of these three branches are defined and vested by the Constitution of the United States, U.S. Constitution, which has been in continuous effect since May 4, 1789. The powers and duties of these branches are further defined by Act of Congress, Acts of Congress, including the creation of United States federal executive departments, executive departments and courts subordinate to the Supreme Court of the United States, U.S. Supreme Court. In the Federalism in the United States, federal division of power, the federal government shares sovereignty with each of the 50 states in their respective t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Civil Engineering Organizations
Civil may refer to: *Civility, orderly behavior and politeness *Civic virtue, the cultivation of habits important for the success of a society *Civil (journalism) ''The Colorado Sun'' is an online news outlet based in Denver, Colorado. It launched on September 10, 2018, to provide long-form, in-depth coverage of news from all around Colorado. It was started with two years of funding from blockchain ventu ..., a platform for independent journalism * Civil (surname) See also * {{Disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Accelerometer
An accelerometer is a device that measures the proper acceleration of an object. Proper acceleration is the acceleration (the rate of change (mathematics), rate of change of velocity) of the object relative to an observer who is in free fall (that is, relative to an inertial frame of reference). Proper acceleration is different from coordinate acceleration, which is acceleration with respect to a given coordinate system, which may or may not be accelerating. For example, an accelerometer at rest on the surface of the Earth will measure an Gravitational acceleration, acceleration due to Earth's gravity straight upwards of about Standard gravity, ''g'' ≈ 9.81 m/s2. By contrast, an accelerometer that is in free fall will measure zero acceleration. Accelerometers have many uses in industry, consumer products, and science. Highly sensitive accelerometers are used in inertial navigation systems for aircraft and missiles. In unmanned aerial vehicles, accelerometers help to stabili ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Structural Dynamics
Structural dynamics is a type of structural analysis which covers the behavior of a structure subjected to dynamic (actions having high acceleration) loading. Dynamic loads include people, wind, waves, traffic, earthquakes, and blasts. Any structure can be subjected to dynamic loading. Dynamic analysis can be used to find dynamic displacements, time history, and modal analysis. Structural analysis is mainly concerned with finding out the behavior of a physical structure when subjected to force. This action can be in the form of load due to the weight of things such as people, furniture, wind, snow, etc. or some other kind of excitation such as an earthquake, shaking of the ground due to a blast nearby, etc. In essence all these loads are dynamic, including the self-weight of the structure because at some point in time these loads were not there. The distinction is made between the dynamic and the static analysis on the basis of whether the applied action has enough acceleration i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Penetration (weapons)
Armour-piercing ammunition (AP) is a type of projectile designed to penetrate armour protection, most often including naval armour, body armour, and vehicle armour. The first, major application of armour-piercing projectiles was to defeat the thick armour carried on many warships and cause damage to their lightly armoured interiors. From the 1920s onwards, armour-piercing weapons were required for anti-tank warfare. AP rounds smaller than 20 mm are intended for lightly armoured targets such as body armour, bulletproof glass, and lightly armoured vehicles. As tank armour improved during World War II, anti-vehicle rounds began to use a smaller but dense penetrating body within a larger shell, firing at a very-high muzzle velocity. Modern penetrators are long rods of dense material like tungsten or depleted uranium (DU) that further improve the terminal ballistics. Penetration In the context of weaponry, ''penetration'' is the ability of a weapon or projectile to pierce into ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air Blast
Atmospheric focusing is a type of wave interaction causing shock waves to affect areas at a greater distance than otherwise expected. Variations in the atmosphere create distortions in the wavefront by refracting a segment, allowing it to converge at certain points and constructively interfere. In the case of destructive shock waves, this may result in areas of damage far beyond the theoretical extent of its blast effect. Examples of this are seen during supersonic booms, large extraterrestrial impacts from objects like meteors, and nuclear explosions. Density variations in the atmosphere (e.g. due to temperature variations), or airspeed variations cause refraction along the shock wave, allowing the uniform wavefront to separate and eventually interfere, dispersing the wave at some points and focusing it at others. A similar effect occurs in water when a wave travels through a patch of different density fluid, causing it to diverge over a large distance. For powerful shock waves ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Government Contractor
A government contractor is a company ( privately owned, publicly traded or a state-owned enterprise)either for profit or non-profitthat produces goods or services under contract for the government. Some communities are largely sustained by government contracting activity; for instance, much of the economy of Northern Virginia consists of government contractors employed directly or indirectly by the federal government of the United States. Terminology Frequently a term public contractor is used to describe the government contractor. In ancient Rome, term publican was used for private individuals that performed work on public buildings, supplied Roman armies, or collected taxes. United Kingdom Section 12(2) and (3) of the Official Secrets Act 1989 define the expression "Government Contractor" for the purposes of that Act. United States The United States federal government seeks to select contractors in a way that is fair to all and promotes the free market system. Contrac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Security Clearance
A security clearance is a status granted to individuals allowing them access to classified information (state or organizational secrets) or to restricted areas, after completion of a thorough background check. The term "security clearance" is also sometimes used in private organizations that have a formal process to vet employees for access to sensitive information. A clearance by itself is normally not sufficient to gain access; the organization must also determine that the cleared individual needs to know specific information. No individual is supposed to be granted automatic access to classified information solely because of rank, position, or a security clearance.(Abiodun, 2006) Canada United Kingdom National Security Clearance types National Security Clearances are a hierarchy of levels, depending on the classification of materials that can be accessed—Baseline Personnel Security Standard (BPSS), Counter-Terrorist Check (CTC), Enhanced Baseline Standard (EBS), Se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Explosion
An explosion is a rapid expansion in volume of a given amount of matter associated with an extreme outward release of energy, usually with the generation of high temperatures and release of high-pressure gases. Explosions may also be generated by a slower expansion that would normally not be forceful, but is not allowed to expand, so that when whatever is containing the expansion is broken by the pressure that builds as the matter inside tries to expand, the matter expands forcefully. An example of this is a Volcano, volcanic eruption created by the expansion of magma in a magma chamber as it rises to the surface. Supersonic explosions created by high explosives are known as detonations and travel through shock waves. wikt:subsonic, Subsonic explosions are created by low explosives through a slower combustion process known as deflagration. Causes For an explosion to occur, there must be a rapid, forceful expansion of matter. There are numerous ways this can happen, both natura ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Classified Information
Classified information is confidential material that a government deems to be sensitive information which must be protected from unauthorized disclosure that requires special handling and dissemination controls. Access is restricted by law or regulation to particular groups of individuals with the necessary security clearance with a need to know. A formal security clearance is required to view or handle classified material. The clearance process requires a satisfactory background investigation. Documents and other information must be properly marked "by the author" with one of several (hierarchical) levels of sensitivity—e.g. Confidential (C), Secret (S), and Top Secret (S). All classified documents require designation markings on the technical file which is usually located either on the cover sheet, header and footer of page. The choice of level is based on an impact assessment; governments have their own criteria, including how to determine the classification of an inf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
