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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. 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 mega-electron volts (MeV, a unit of energy). The gamma rays penetrate the atmosphere and collide with a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hardtack I Teak 002
Hardtack (or hard tack) is a simple type of dense biscuit or 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, hardtack was a standard ration for many militaries and navies from the 17th through the early 20th centuries. Etymology The name is derived from "tack", the British sailor slang for food. 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'', or pejoratively as ''dog biscuits'', ''molar breakers'', ''sheet iron'', ''tooth dullers'', ''armor plates'' (Germany) and ''worm castles''. Australian and New Zealand military personnel knew them with some sarcasm as ''ANZAC wafers'' (not to be confused with Anzac biscuit) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromagnetic Radiation
In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic field, electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy. It includes radio waves, microwaves, infrared, Light, (visible) light, ultraviolet, X-rays, and gamma rays. All of these waves form part of the electromagnetic spectrum. Classical electromagnetism, Classically, electromagnetic radiation consists of electromagnetic waves, which are synchronized oscillations of electric field, electric and magnetic fields. Depending on the frequency of oscillation, different wavelengths of electromagnetic spectrum are produced. In a vacuum, electromagnetic waves travel at the speed of light, commonly denoted ''c''. In homogeneous, isotropic media, the oscillations of the two fields are perpendicular to each other and perpendicular to the direction of energy and wave propagation, forming a transverse wave. The position of an electromagnetic wave w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microwave Radio Relay
Microwave transmission is the transmission of information by electromagnetic waves with wavelengths in the microwave frequency range of 300MHz to 300GHz(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 multiplex eight telephone channels over long distances. A link across the English Channel allow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microwave
Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency ranges as microwaves; the above broad definition includes both UHF and EHF (millimeter wave) bands. A more common definition in radio-frequency engineering is the range between 1 and 100 GHz (wavelengths between 0.3 m and 3 mm). In all cases, microwaves include the entire SHF band (3 to 30 GHz, or 10 to 1 cm) at minimum. Frequencies in the microwave range are often referred to by their IEEE radar band designations: S, C, X, Ku, K, or Ka band, or by similar NATO or EU designations. The prefix ' in ''microwave'' is not meant to suggest a wavelength in the micrometer range. Rather, it indicates that microwaves are "small" (having shorter wavelengths), compared to the radio waves used prior to microwave te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Burglar Alarm
A security alarm is a system designed to detect intrusion, such as unauthorized entry, into a building or other areas such as a home or school. Security alarms used in residential, commercial, industrial, and military properties protect against burglary (theft) or property damage, as well as personal protection against intruders. Security alerts in neighborhoods show a connection with diminished robbery. Car alarms likewise help protect vehicles and their contents. Prisons also use security systems for the control of inmates. Some alarm systems serve a single purpose of burglary protection; combination systems provide 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 complica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oahu
Oahu () (Hawaiian language, Hawaiian: ''Oʻahu'' ()), also known as "The Gathering place#Island of Oʻahu as The Gathering Place, Gathering Place", is the third-largest of the Hawaiian Islands. It is home to roughly one million people—over two-thirds of the population of the U.S. state of Hawaii. The island of O’ahu and the Northwestern Hawaiian Islands constitute the City and County of Honolulu, Hawaii, City and County of Honolulu. The state capital, Honolulu, is on Oʻahu's southeast coast. Oʻahu had a population of 1,016,508 according to the 2020 U.S. Census, up from 953,207 people in 2010 (approximately 70% of the total 1,455,271 population of the State of Hawaii, with approximately 81% of those living in or near the Honolulu urban area). Name The Island of O{{okinaahu in Hawaii is often nicknamed (or translated as) ''"The Gathering Place"''. It appears that O{{okinaahu grew into this nickname; it is currently the most populated Hawaiian islands, Hawaiian Island, how ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island country by area, covering . New Zealand is about east of Australia across the Tasman Sea and south of the islands of New Caledonia, Fiji, and Tonga. The country's varied topography and sharp mountain peaks, including the Southern Alps, owe much to tectonic uplift and volcanic eruptions. 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 then developed a distinctive Māori culture. In 1642, the Dutch explorer Abel Tasman became the first European to sight and record New Zealand. In 1840, representatives of the United Kingdom and Māori chiefs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Honolulu
Honolulu (; ) is the capital and largest city of the U.S. state of Hawaii, which is in the Pacific Ocean. It is an unincorporated county seat of the consolidated City and County of Honolulu, situated along the southeast coast of the island of Oahu, and is the westernmost and southernmost major U.S. city. Honolulu is Hawaii's main gateway to the world. 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, Western, and Pacific cultures, reflected in its diverse demography, cuisine, and traditions. ''Honolulu'' means "sheltered harbor" or "calm port" in Hawaiian; its old name, ''Kou'', roughly encompasses the area from Nuuanu Avenue to Alakea Street and from Hotel Street to Queen Street, which is the heart of the present downtown district. The city's desirability as a port accounts for its historical growth and importance in the Hawaiian archipelago and the broader P ... [...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, 1961, tha ... [...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 caused by a solar wind shock wave and/or cloud of magnetic field that interacts with the Earth's magnetic field. The disturbance that drives the magnetic storm may be a solar coronal mass ejection (CME) or (much less severely) a co-rotating interaction region (CIR), a high-speed stream of solar wind originating from a coronal hole. The frequency of geomagnetic storms increases and decreases with the sunspot cycle. During solar maximum, geomagnetic storms occur more often, with the majority driven by CMEs. 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 the magnetosphere. Both interactions cause an increase in plasma movement through the magnetosphere (driven by increased electric fields inside the magnetosphere) and an increase i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Samoa
Samoa, officially the Independent State of Samoa; sm, Sāmoa, and until 1997 known as Western Samoa, is a Polynesian island country consisting 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 (Nu'utele, Nu'ulua, Fanuatapu and Namua). Samoa is located west of American Samoa, northeast of Tonga (closest foreign country), northeast of Fiji, east of Wallis and Futuna, southeast of Tuvalu, south of Tokelau, southwest of Hawaii, and northwest of Niue. The capital 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 Samoan culture, Samoan cultural identity. Samoa is a Unitary state, unitary Parliamentary system, parliamentary democracy with 11 Administrative divisions of Samoa, administrative divisions. It is a sovereign state and a member of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apia
Apia () is the Capital (political), capital and largest city of Samoa, as well as the nation's only city. 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 37,391 (2016 census). Its geographic boundaries extend roughly from Letogo village to the newer, industrialized region of Apia known as "Vaitele". 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 founded in the 1850s, and it has been ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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