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High-altitude Nuclear Explosion
High-altitude nuclear explosions are the result of nuclear weapons testing within the upper layers of the Earth's atmosphere and in outer space. Several such tests were performed at high altitudes by the United States and the Soviet Union between 1958 and 1962. The Partial Test Ban Treaty was passed in October 1963, ending atmospheric and exoatmospheric nuclear tests. The Outer Space Treaty of 1967 banned the stationing of nuclear weapons in space, in addition to other weapons of mass destruction. The Comprehensive Nuclear-Test-Ban Treaty of 1996 prohibits all nuclear testing; whether over- or underground, underwater or in the atmosphere, but hasn't entered into force yet as it hasn't been ratified by some of the states party to the Treaty. EMP generation The strong electromagnetic pulse (EMP) that results has several components. In the first few tenths of nanoseconds, about a tenth of a percent of the weapon yield appears as powerful gamma rays with energies of one to three ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hardtack I Teak 002
Hardtack (or hard tack) is a type of dense cracker made from flour, water, and sometimes salt. Hardtack is inexpensive and long-lasting. It is used for sustenance in the absence of perishable foods, commonly during long sea voyages, land migrations, and military campaigns. Along with salt pork and corned beef, hardtack was a standard ration for many militaries and navies from the 17th to the early 20th centuries. Etymology The name is derived from "tack", the British sailor slang for food. The earliest use of the term recorded by the ''Oxford English Dictionary'' is from 1830. It is known by other names including ''brewis'' (possibly a cognate with "brose"), ''cabin bread'', ''pilot bread'', ''sea biscuit'', ''soda crackers'', ''sea bread'' (as rations for sailors), ''ship's biscuit'', and pejoratively as '' dog biscuits'', '' molar breakers'', ''sheet iron'', ''tooth dullers'', ''Panzerplatten'' ("''armor plates''"; Germany) and ''worm castles''. Australian and New Zealand mili ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromagnetic Radiation
In physics, electromagnetic radiation (EMR) is a self-propagating wave of the electromagnetic field that carries momentum and radiant energy through space. It encompasses a broad spectrum, classified by frequency or its inverse, wavelength, ranging from radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays. All forms of EMR travel at the speed of light in a vacuum and exhibit wave–particle duality, behaving both as waves and as discrete particles called photons. Electromagnetic radiation is produced by accelerating charged particles such as from the Sun and other celestial bodies or artificially generated for various applications. Its interaction with matter depends on wavelength, influencing its uses in communication, medicine, industry, and scientific research. Radio waves enable broadcasting and wireless communication, infrared is used in thermal imaging, visible light is essential for vision, and higher-energy radiation, such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microwave Radio Relay
Microwave transmission is the Data transmission, transmission of information by electromagnetic waves with wavelengths in the microwave frequency range of 300 MHz to 300 GHz (1 m - 1 mm wavelength) of the electromagnetic spectrum. Microwave signals are normally limited to the line of sight, so long-distance transmission using these signals requires a series of repeaters forming a microwave relay network. It is possible to use microwave signals in over-the-horizon communications using tropospheric scatter, but such systems are expensive and generally used only in specialist roles. Although an experimental microwave telecommunication link across the English Channel was demonstrated in 1931, the development of radar in World War II provided the technology for practical exploitation of microwave communication. During the war, the British Army introduced the Wireless Set No. 10, which used microwave relays to multiplexing, multiplex eight telephone channels over long ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microwave
Microwave is a form of electromagnetic radiation with wavelengths shorter than other radio waves but longer than infrared waves. Its wavelength ranges from about one meter to one millimeter, corresponding to frequency, frequencies between 300 MHz and 300 GHz, broadly construed. A more common definition in radio-frequency engineering is the range between 1 and 100 GHz (wavelengths between 30 cm and 3 mm), or between 1 and 3000 GHz (30 cm and 0.1 mm). In all cases, microwaves include the entire super high frequency, super high frequency (SHF) band (3 to 30 GHz, or 10 to 1 cm) at minimum. The boundaries between far infrared, terahertz radiation, microwaves, and ultra-high-frequency (UHF) are fairly arbitrary and differ between different fields of study. The prefix ' in ''microwave'' indicates that microwaves are small (having shorter wavelengths), compared to the radio waves used in prior radio technology. Frequencies in the micr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Burglar Alarm
A security alarm is a system designed to detect intrusions, such as unauthorized entry, into a building or other areas, such as a home or school. Security alarms protect against burglary (theft) or property damage, as well as against intruders. Examples include personal systems, neighborhood security alerts, car alarms, and prison alarms. Some alarm systems serve a single purpose of burglary protection; combination systems provide Fire alarm system, fire and intrusion protection. Intrusion-alarm systems are combined with closed-circuit television surveillance (CCTV) systems to record intruders' activities and interface to access control systems for electrically locked doors. There are many types of security systems. Homeowners typically have small, self-contained noisemakers. These devices can also be complicated, multirole systems with computer and network surveillance, computer monitoring and control. It may even include a two-way voice which allows communication between the pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oahu
Oahu (, , sometimes written Oahu) is the third-largest and most populated island of the Hawaiian Islands and of the U.S. state of Hawaii. The state capital, Honolulu, is on Oahu's southeast coast. The island of Oahu and the uninhabited Northwestern Hawaiian Islands constitute the City and County of Honolulu, Hawaii, City and County of Honolulu. In 2021, Oahu had a population of 995,638, up from 953,207 in 2010 (approximately 70% of the total 1,455,271 population of the Hawaiian Islands, with approximately 81% of those living in or near the Honolulu urban area). Oahu is long and across. Its shoreline is long. Including small associated islands such as Ford Island plus those in Kāneohe Bay and off the eastern (windward and leeward, windward) coast, its area is , making it the List of islands of the United States by area, 20th-largest island in the United States. Well-known features of Oahu include Waikīkī, Pearl Harbor, Diamond Head, Hawaii, Diamond Head, Hanauma Bay, Kān ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New Zealand
New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of island countries, sixth-largest island country by area and lies east of Australia across the Tasman Sea and south of the islands of New Caledonia, Fiji, and Tonga. The Geography of New Zealand, country's varied topography and sharp mountain peaks, including the Southern Alps (), owe much to tectonic uplift and volcanic eruptions. Capital of New Zealand, New Zealand's capital city is Wellington, and its most populous city is Auckland. The islands of New Zealand were the last large habitable land to be settled by humans. Between about 1280 and 1350, Polynesians began to settle in the islands and subsequently developed a distinctive Māori culture. In 1642, the Dutch explorer Abel Tasman became the first European to sight and record New Zealand. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Honolulu
Honolulu ( ; ) is the List of capitals in the United States, capital and most populous city of the U.S. state of Hawaii, located in the Pacific Ocean. It is the county seat of the Consolidated city-county, consolidated City and County of Honolulu County, Hawaii, Honolulu, situated along the southeast coast of the island of Oahu, Oʻahu, and is the westernmost and southernmost major U.S. city as well as westernmost and southernmost U.S. state capital. It is also a major hub for business, finance, hospitality, and military defense in both the state and Oceania. The city is characterized by a mix of various Asian culture, Asian, Western culture, Western, and Oceanian culture, Pacific cultures, reflected in its diverse demography, cuisine, and traditions. is Hawaiian language, Hawaiian for "sheltered harbor" or "calm port"; its old name, , roughly encompasses the area from Nuʻuanu Avenue to Alakea Street and from Hotel Street to Queen Street, which is the heart of the present dow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Starfish Prime
Starfish Prime was a high-altitude nuclear test conducted by the United States, a joint effort of the Atomic Energy Commission (AEC) and the Defense Atomic Support Agency. It was launched from Johnston Atoll on July 9, 1962, and was the largest nuclear test conducted in outer space, and one of five conducted by the US in space. A Thor rocket carrying a W49 thermonuclear warhead (designed at Los Alamos Scientific Laboratory) and a Mk. 2 reentry vehicle was launched from Johnston Atoll in the Pacific Ocean, about west-southwest of Hawaii. The explosion took place at an altitude of , above a point southwest of Johnston Atoll. It had a yield of . The explosion was about 10° above the horizon as seen from Hawaii, at 11 pm Hawaii time. Operation Fishbowl The Starfish test was one of five high-altitude tests grouped together as Operation Fishbowl within the larger Operation Dominic, a series of tests in 1962 begun in response to the Soviet announcement on August 30 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geomagnetic Storm
A geomagnetic storm, also known as a magnetic storm, is a temporary disturbance of the Earth's magnetosphere that is driven by interactions between the magnetosphere and large-scale transient Plasma (physics), plasma and magnetic field structures that originate on or near the Sun. The structures that produce geomagnetic storms include interplanetary coronal mass ejections (CME) and corotating interaction regions (CIR). The former often originate from solar active regions, while the latter originate at the boundary between high- and low-speed streams of solar wind. The frequency of geomagnetic storms increases and decreases with the sunspot cycle. During solar maximum, solar maxima, geomagnetic storms occur more often, with the majority driven by CMEs. When these structures reach Earth, the increase in the solar wind pressure initially compresses the magnetosphere. The solar wind's magnetic field interacts with the Earth's magnetic field and transfers an increased energy into th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Samoa
Samoa, officially the Independent State of Samoa and known until 1997 as Western Samoa, is an island country in Polynesia, part of Oceania, in the South Pacific Ocean. It consists of two main islands (Savai'i and Upolu), two smaller, inhabited islands (Manono Island, Manono and Apolima), and several smaller, uninhabited islands, including the Aleipata Islands (Nuʻutele, Nuʻulua, Fanuatapu and Namua). Samoa is located west of American Samoa, northeast of Tonga, northeast of Fiji, east of Wallis and Futuna, southeast of Tuvalu, south of Tokelau, southwest of Hawaii, and northwest of Niue. The capital and largest city is Apia. The Lapita culture, Lapita people discovered and settled the Samoan Islands around 3,500 years ago. They developed a Samoan language and Culture of Samoa, Samoan cultural identity. Samoa is a Unitary state, unitary Parliamentary system, parliamentary democracy with 11 Districts of Samoa, administrative divisions. It is a sovereign state and a membe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apia
Apia () is the Capital (political), capital and largest city of Samoa. It is located on the central north coast of Upolu, Samoa's second-largest island. Apia falls within the political district (''itūmālō'') of Tuamasaga. The Apia Urban Area (generally known as the City of Apia) has a population of 35,974 (2021 census). Its geographic boundaries extend from the east approximately from Letogo village in Vaimauga to the west in the newer, industrialized region of Apia which extends to Vaitele village in Faleata. History Apia was originally a small village (the 1800 population was 304), from which the country's capital took its name. Apia Village still exists within the larger modern capital of Apia, which has grown into a sprawling urban area that encompasses many villages. Like every other settlement in the country, Apia Village has its own ''matai'' (leaders) and ''fa'alupega'' (genealogy and customary greetings) according to fa'a Samoa. The modern city of Apia was foun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
