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LRAD
A long-range acoustic device (LRAD) is an acoustic hailing device (AHD), sound cannon and sonic weapon developed by Genasys. It has been used as a method of crowd control, which has caused permanent hearing damage, having an extremely high decibel capacity (up to 160 dB measured at one meter from the device). Other uses have included for negotiations in siege situations to deal with piracy at sea; for mass notification during natural disasters or other emergencies; and by defense forces, including several navies. History In October 2000 the , an American guided missile destroyer, was bombed in a terrorist attack by al-Qaeda operatives, using a small boat packed with explosives. The naval personnel on Cole were unable to be sure that their messages could be heard by the approaching boat at a sufficient distance to possibly avert the attack. The ship was badly damaged, 17 U.S. Navy sailors killed and 37 injured. Following this attack, navies around the world made s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genasys
Genasys Inc. is based in San Diego, California. Its long-range acoustic device (LRAD) products are used for long-range acoustic hailing and mass notification. The company was previously named American Technology Corporation (ATC) until 2010 and as LRAD Corporation until 2019. The company's stock trades on the NASDAQ Capital Market with the ticker symbol "GNSS". History Genasys was founded in Utah by Elwood "Woody" Norris as the American Technology Corporation in 1980. From 1988 to early 1992 the company was inactive. Norris recapitalized the company as a Delaware Corporation in 1992. In 1996, the company launched its first directed sound technology and began engineering sound solutions for the commercial, government, and military markets. In response to the October 2000 attack on the USS ''Cole'', the company's engineering team developed their long-range acoustic device (LRAD) product line. With the introduction of LRAD systems in 2003, the company created the acoustic hailing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sonic Weapon
Sonic and ultrasonic weapons (USW) are weapons of various types that use sound to injure or incapacitate an opponent. Some sonic weapons make a focused beam of sound or of ultrasound; others produce an area field of sound. military and police forces make some limited use of sonic weapons. Use and deployment Extremely high-power sound waves can disrupt or destroy the eardrums of a target and cause severe pain or disorientation. This is usually sufficient to incapacitate a person. Less powerful sound waves can cause humans to experience nausea or discomfort. The possibility of a device that produces frequency that causes vibration of the eyeballs—and therefore distortion of vision—was suggested by paranormal researcher Vic Tandy in the 1990s while attempting to demystify a "haunting" in his laboratory in Coventry. This "spook" was characterised by a feeling of unease and vague glimpses of a grey apparition. Some detective work implicated a newly-installed extractor fan, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Piracy
Piracy is an act of robbery or criminal violence by ship or boat-borne attackers upon another ship or a coastal area, typically with the goal of stealing cargo and other valuable goods. Those who conduct acts of piracy are called pirates, vessels used for piracy are pirate ships. The earliest documented instances of piracy were in the 14th century BC, when the Sea Peoples, a group of ocean raiders, attacked the ships of the Aegean and Mediterranean civilisations. Narrow channels which funnel shipping into predictable routes have long created opportunities for piracy, as well as for privateering and commerce raiding. Historic examples include the waters of Gibraltar, the Strait of Malacca, Madagascar, the Gulf of Aden, and the English Channel, whose geographic structures facilitated pirate attacks. The term ''piracy'' generally refers to maritime piracy, although the term has been generalized to refer to acts committed on land, in the air, on computer networks, and (in scie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acoustic Hailing Device
An acoustic hailing device (AHD) is a specialized loudspeaker that produces sound at high power for communicating at a distance. AHDs vary in design, output, and usability. Overview Acoustic hailing devices are acoustic devices capable of outputting highly intelligible sound at very high volumes. The distance at which acoustic hailing can be effective varies based on several factors including the sound level, directionality, and frequency of the acoustic source, the sensitivity and directionality of the receiver, and the transmission channel environment. The sound level diminishes or attenuates with distance. Consequently, as a general rule, higher source levels have greater range. Acoustic hailing devices can come in two forms; # Directional models: These AHDs are characterized by their ability to create long-range, directional voice communications and warning tones. Their directionality is typically 5° to 60° radius conical at a 2 kHz tone. # Omnidirectional models: T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coast Guard
A coast guard or coastguard is a maritime security organization of a particular country. The term embraces wide range of responsibilities in different countries, from being a heavily armed military force with customs and security duties to being a volunteer organization tasked with search and rescue without law enforcement authority. In most countries, a typical coast guard's functions are distinct from those of the navy (a military service) and the transit police (a law enforcement agency), while in certain countries has similarities to both. History The predecessor of the United Kingdom's modern His Majesty's Coastguard was established in 1809 as the Waterguard, a department of the HM Customs and Excise authority, which was originally devoted to the prevention of smuggling. At the time, due to high UK taxation on liquors such as brandy, and on tobacco etc., smuggling of such cargoes from places such as France, Belgium, and Holland was an attractive proposition for many; ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Near And Far Field
The near field and far field are regions of the electromagnetic (EM) field around an object, such as a transmitting antenna, or the result of radiation scattering off an object. Non-radiative ''near-field'' behaviors dominate close to the antenna or scattering object, while electromagnetic radiation ''far-field'' behaviors dominate at greater distances. Far-field E (electric) and B (magnetic) field strength decreases as the distance from the source increases, resulting in an inverse-square law for the radiated ''power'' intensity of electromagnetic radiation. By contrast, near-field E and B strength decrease more rapidly with distance: the radiative field decreases by the inverse-distance squared, the reactive field by an inverse-cube law, resulting in a diminished power in the parts of the electric field by an inverse fourth-power and sixth-power, respectively. The rapid drop in power contained in the near-field ensures that effects due to the near-field essentially vanish a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Wiley And Sons
John Wiley & Sons, Inc., commonly known as Wiley (), is an American multinational publishing company founded in 1807 that focuses on academic publishing and instructional materials. The company produces books, journals, and encyclopedias, in print and electronically, as well as online products and services, training materials, and educational materials for undergraduate, graduate, and continuing education students. History The company was established in 1807 when Charles Wiley opened a print shop in Manhattan. The company was the publisher of 19th century American literary figures like James Fenimore Cooper, Washington Irving, Herman Melville, and Edgar Allan Poe, as well as of legal, religious, and other non-fiction titles. The firm took its current name in 1865. Wiley later shifted its focus to scientific, technical, and engineering subject areas, abandoning its literary interests. Wiley's son John (born in Flatbush, New York, October 4, 1808; died in East Orange, New Jer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jet Engine
A jet engine is a type of reaction engine discharging a fast-moving jet of heated gas (usually air) that generates thrust by jet propulsion. While this broad definition can include rocket, Pump-jet, water jet, and hybrid propulsion, the term typically refers to an internal combustion airbreathing jet engine such as a turbojet, turbofan, ramjet, or pulse jet engine, pulse jet. In general, jet engines are internal combustion engines. Airbreathing jet engines typically feature a Axial compressor, rotating air compressor powered by a turbine, with the leftover power providing thrust through the propelling nozzle—this process is known as the Brayton cycle, Brayton thermodynamic cycle. Jet aircraft use such engines for long-distance travel. Early jet aircraft used turbojet engines that were relatively inefficient for subsonic flight. Most modern subsonic jet aircraft use more complex High-bypass turbofan, high-bypass turbofan engines. They give higher speed and greater fuel eff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gunshot
A gunshot is a single discharge of a gun, typically a man-portable firearm, producing a visible flash, a powerful and loud shockwave and often chemical gunshot residue. The term can also refer to a ballistic wound caused by such a discharge. Multiple discharges of one or more firearms are referred to as gunfire. The word can connote either the sound of a gun firing, the projectiles that were fired, or both. For example, the statement "gunfire came from the next street" could either mean the sound of discharge, or it could mean the bullets that were discharged. It is better to be a bit more specific while writing however. "The sound of gunfire" or "we came under gunfire" would be more descriptive and prevent confusion. In the latter phrase, in particular, "fire" is used more (i.e. "under fire"), as both words hold the same general meaning within the proper context. Gunfire characteristics There are three primary attributes that characterize gunfire and hence enable the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fire And Rescue
A fire department (American English) or fire brigade (Commonwealth English), also known as a fire authority, fire district, fire and rescue, or fire service in some areas, is an organization that provides fire prevention and fire suppression services. Fire departments are most commonly a public sector organization that operate within a municipality, county, state, nation, or special district. Private and specialist firefighting organizations also exist, such as those for aircraft rescue and firefighting. A fire department contains one or more fire stations within its boundaries, and may be staffed by firefighters, who may be professional, volunteers, conscripts, or on-call. Combination fire departments employ a mix of professional and volunteer firefighters. Organization Fire departments are organized in a system of administration, services, training, and operations; for example: * Administration is responsible for supervision, budgets, policy, and human resources. * Servic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naval Base
A naval base, navy base, or military port is a military base, where warships and naval ships are docked when they have no mission at sea or need to restock. Ships may also undergo repairs. Some naval bases are temporary homes to aircraft that usually stay on ships but are undergoing maintenance while the ship is in port. In the United States, the United States Department of the Navy's General Order No. 135 issued in 1911 as a formal guide to naval terminology described a naval station as "any establishment for building, manufacturing, docking, repair, supply, or training under control of the Navy. It may also include several establishments". A naval base, by contrast, was "a point from which naval operations may be conducted". In most countries, naval bases are expressly named and identified as such. One peculiarity of the Royal Navy and certain other navies which closely follow British naval traditions is the concept of the stone frigate A stone frigate is a naval esta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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