title: Waste management

text: Waste collection methods vary widely among different countries and regions. Domestic waste collection services are often provided by local government authorities, or by private companies for industrial and commercial waste. Some areas, especially those in less developed countries, do not have formal waste-collection systems.


title: Waste management

text: Curbside collection is the most common method of disposal in most European countries, Canada, New Zealand, United States, and many other parts of the developed world in which waste is collected at regular intervals by specialised trucks. This is often associated with curb-side waste segregation. In rural areas, waste may need to be taken to a transfer station. Waste collected is then transported to an appropriate disposal facility.


title: Waste management

text: In some areas, vacuum collection is used in which waste is transported from the home or commercial premises by vacuum along small bore tubes. Systems are in use in Europe and North America.


title: Waste management

text: In some jurisdictions unsegregated waste is collected at the curb-side or from waste transfer stations and then sorted into recyclables and unusable waste. Such systems are capable of sorting large volumes of solid waste, salvaging recyclables, and turning the rest into bio-gas and soil conditioner.


title: Waste management

text: In San Francisco, the local government established its "Mandatory Recycling and Composting Ordinance" in support of its goal of "Zero waste by 2020", requiring everyone in the city to keep recyclables and compostables out of the landfill. The three streams are collected with the curbside "Fantastic 3" bin system – blue for recyclables, green for compostables, and black for landfill-bound materials – provided to residents and businesses and serviced by San Francisco's sole refuse hauler, Recology. The city's "Pay-As-You-Throw" system charges customers by the volume of landfill-bound materials, which provides a financial incentive to separate recyclables and compostables from other discards. The city's Department of the Environment's Zero Waste Program has led the city to achieve 80% diversion, the highest diversion rate in North America. Other businesses such as Waste Industries use a variety of colors to distinguish between trash and recycling cans. In addition, in some areas of the world the disposal of municipal solid waste can cause environmental strain due to official not having benchmarks that help measure the environmental sustainability of certain practices.


title: Waste management

text: This is the separation of wet waste and dry waste. The purpose is to recycle dry waste easily and to use wet waste as compost. When segregating waste, the amount of waste that gets landfilled reduces considerably, resulting in lower levels of air and water pollution. Importantly, waste segregation should be based on the type of waste and the most appropriate treatment and disposal. This also makes it easier to apply different processes to the waste, like composting, recycling and incineration. It is important to practice waste management and segregation as a community. One way to practice waste management is to ensure there is awareness. The process of waste segregation should be explained to the community.


title: Waste management

text: Segregated waste is also often cheaper to dispose of because it does not require as much manual sorting as mixed waste. There are a number of important reasons why waste segregation is important such as legal obligations, cost savings and protection of human health and the environment. Institutions should make it as easy as possible for their staff to correctly segregate their waste. This can include labelling, making sure there are enough accessible bins and clearly indicating why segregation is so important. Labeling is especially important when dealing with nuclear waste due to how much harm to human health the excess products of the nuclear cycle can cause.


title: Waste management

text: In most developed countries, domestic waste disposal is funded from a national or local tax which may be related to income, or property values. Commercial and industrial waste disposal is typically charged for as a commercial service, often as an integrated charge which includes disposal costs. This practice may encourage disposal contractors to opt for the cheapest disposal option such as landfill rather than the environmentally best solution such as re-use and recycling.


title: Waste management

text: Financing of solid waste management projects can be overwhelming for the city government, especially if the government see it as an important service they should render to the citizen. Donors and grants are a funding mechanism that is dependent on the interest of the donor organization. as much as it is a good way to develop a city's waste management infrastructure, attracting and utilizing grants is solely reliant on what the donor considers as important. Therefore, it may be a challenge for a city government to dictate how the funds should be distributed among the various aspect of waste management.


title: Waste management

text: In some areas like Taipei, the city government charges its households and industries for the volume of rubbish they produce. Waste is collected by the city council only if it is put in government issued rubbish bags. This policy has successfully reduced the amount of waste the city produces and increased the recycling rate.


title: Waste management

text: Another example from a country that enforces a waste tax is Italy. Instead of using government issued bags like Taipei, the tax is based on two rates: fixed and variable. The fixed rate is based on the size of the house while the variable is determined by the amount of people living in the house.


title: Waste management

text: The World Bank finances and advises on solid waste management projects using a diverse suite of products and services, including traditional loans, results-based financing, development policy financing, and technical advisory. World Bank-financed waste management projects usually address the entire lifecycle of waste right from the point of generation to collection and transportation, and finally treatment and disposal.


title: Waste management

text: Incineration is a disposal method in which solid organic wastes are subjected to combustion so as to convert them into residue and gaseous products. This method is useful for disposal of both municipal solid waste and solid residue from waste water treatment. This process reduces the volumes of solid waste by 80 to 95 percent. Incineration and other high temperature waste treatment systems are sometimes described as "thermal treatment". Incinerators convert waste materials into heat, gas, steam, and ash.


title: Waste management

text: Incineration is carried out both on a small scale by individuals and on a large scale by industry. It is used to dispose of solid, liquid and gaseous waste. It is recognized as a practical method of disposing of certain hazardous waste materials (such as biological medical waste). Incineration is a controversial method of waste disposal, due to issues such as emission of gaseous pollutants including substantial quantities of carbon dioxide.


title: Waste management

text: Incineration is common in countries such as Japan where land is more scarce, as the facilities generally do not require as much area as landfills. Waste-to-energy (WtE) or energy-from-waste (EfW) are broad terms for facilities that burn waste in a furnace or boiler to generate heat, steam or electricity. Combustion in an incinerator is not always perfect and there have been concerns about pollutants in gaseous emissions from incinerator stacks. Particular concern has focused on some very persistent organic compounds such as dioxins, furans, and PAHs, which may be created and which may have serious environmental consequences and some heavy metals such as mercury and lead which can be volatilised in the combustion process..


title: Waste management

text: Recycling is a resource recovery practice that refers to the collection and reuse of waste materials such as empty beverage containers. This process involves breaking down and reusing materials that would otherwise be gotten rid of as trash. There are numerous benefits of recycling, and with so many new technologies making even more materials recyclable, it is possible to clean up the Earth. Recycling not only benefits the environment but also positively affects the economy. The materials from which the items are made can be made into new products. Materials for recycling may be collected separately from general waste using dedicated bins and collection vehicles, a procedure called kerbside collection. In some communities, the owner of the waste is required to separate the materials into different bins (e.g. for paper, plastics, metals) prior to its collection. In other communities, all recyclable materials are placed in a single bin for collection, and the sorting is handled later at a central facility. The latter method is known as "single-stream recycling."


title: Waste management

text: The most common consumer products recycled include aluminium such as beverage cans, copper such as wire, steel from food and aerosol cans, old steel furnishings or equipment, rubber tyres, polyethylene and PET bottles, glass bottles and jars, paperboard cartons, newspapers, magazines and light paper, and corrugated fiberboard boxes.


title: Waste management

text: PVC, LDPE, PP, and PS (see resin identification code) are also recyclable. These items are usually composed of a single type of material, making them relatively easy to recycle into new products. The recycling of complex products (such as computers and electronic equipment) is more difficult, due to the additional dismantling and separation required.


title: Waste management

text: The type of material accepted for recycling varies by city and country. Each city and country has different recycling programs in place that can handle the various types of recyclable materials. However, certain variation in acceptance is reflected in the resale value of the material once it is reprocessed. Some of the types of recycling include waste paper and cardboard, plastic recycling, metal recycling, electronic devices, wood recycling, glass recycling, cloth and textile and so many more. In July 2017, the Chinese government announced an import ban of 24 categories of recyclables and solid waste, including plastic, textiles and mixed paper, placing tremendous impact on developed countries globally, which exported directly or indirectly to China.


title: Waste management

text: Recoverable materials that are organic in nature, such as plant material, food scraps, and paper products, can be recovered through composting and digestion processes to decompose the organic matter. The resulting organic material is then recycled as mulch or compost for agricultural or landscaping purposes. In addition, waste gas from the process (such as methane) can be captured and used for generating electricity and heat (CHP/cogeneration) maximising efficiencies. There are different types of composting and digestion methods and technologies. They vary in complexity from simple home compost heaps to large scale industrial digestion of mixed domestic waste. The different methods of biological decomposition are classified as aerobic or anaerobic methods. Some methods use the hybrids of these two methods. The anaerobic digestion of the organic fraction of solid waste is more environmentally effective than landfill, or incineration. The intention of biological processing in waste management is to control and accelerate the natural process of decomposition of organic matter. (See resource recovery).


title: Waste management

text: Energy recovery from waste is the conversion of non-recyclable waste materials into usable heat, electricity, or fuel through a variety of processes, including combustion, gasification, pyrolyzation, anaerobic digestion, and landfill gas recovery. This process is often called waste-to-energy. Energy recovery from waste is part of the non-hazardous waste management hierarchy. Using energy recovery to convert non-recyclable waste materials into electricity and heat, generates a renewable energy source and can reduce carbon emissions by offsetting the need for energy from fossil sources as well as reduce methane generation from landfills. Globally, waste-to-energy accounts for 16% of waste management.


title: Waste management

text: The energy content of waste products can be harnessed directly by using them as a direct combustion fuel, or indirectly by processing them into another type of fuel. Thermal treatment ranges from using waste as a fuel source for cooking or heating and the use of the gas fuel (see above), to fuel for boilers to generate steam and electricity in a turbine. Pyrolysis and gasification are two related forms of thermal treatment where waste materials are heated to high temperatures with limited oxygen availability. The process usually occurs in a sealed vessel under high pressure. Pyrolysis of solid waste converts the material into solid, liquid and gas products. The liquid and gas can be burnt to produce energy or refined into other chemical products (chemical refinery). The solid residue (char) can be further refined into products such as activated carbon. Gasification and advanced Plasma arc gasification are used to convert organic materials directly into a synthetic gas (syngas) composed of carbon monoxide and hydrogen. The gas is then burnt to produce electricity and steam.


title: Waste management

text: An alternative to pyrolysis is high temperature and pressure supercritical water decomposition (hydrothermal monophasic oxidation).


title: Waste management

text: Pyrolysis is often used to convert many types of domestic and industrial residues into a recovered fuel. Different types of waste input (such as plant waste, food waste, tyres) placed in the pyrolysis process potentially yield an alternative to fossil fuels. Pyrolysis is a process of thermo-chemical decomposition of organic materials by heat in the absence of stoichiometric quantities of oxygen; the decomposition produces various hydrocarbon gases. During pyrolysis, the molecules of object vibrate at high frequencies to an extent that molecules start breaking down. The rate of pyrolysis increases with temperature. In industrial applications, temperatures are above 430 °C (800 °F).


title: Waste management

text: Slow pyrolysis produces gases and solid charcoal. Pyrolysis hold promise for conversion of waste biomass into useful liquid fuel. Pyrolysis of waste wood and plastics can potentially produce fuel. The solids left from pyrolysis contain metals, glass, sand and pyrolysis coke which does not convert to gas. Compared to the process of incineration, certain types of pyrolysis processes release less harmful by-products that contain alkali metals, sulphur, and chlorine. However, pyrolysis of some waste yields gases which impact the environment such as HCl and SO.


title: Waste management

text: Resource recovery is the systematic diversion of waste, which was intended for disposal, for a specific next use. It is the processing of recyclables to extract or recover materials and resources, or convert to energy. These activities are performed at a resource recovery facility. Resource recovery is not only environmentally important, but it is also cost-effective. It decreases the amount of waste for disposal, saves space in landfills, and conserves natural resources.


title: Waste management

text: Resource recovery (as opposed to waste management) uses LCA (life cycle analysis) attempts to offer alternatives to waste management. For mixed MSW (Municipal Solid Waste) a number of broad studies have indicated that administration, source separation and collection followed by reuse and recycling of the non-organic fraction and energy and compost/fertilizer production of the organic material via anaerobic digestion to be the favoured path.


title: Waste management

text: As an example of how resource recycling can be beneficial, many items thrown away contain metals that can be recycled to create a profit, such as the components in circuit boards. Wood chippings in pallets and other packaging materials can be recycled to useful products for horticulture. The recycled chips can cover paths, walkways, or arena surfaces.


title: Waste management

text: Application of rational and consistent waste management practices can yield a range of benefits including:


title: Waste management

text: Liquid waste is an important category of waste management because it is so difficult to deal with. Unlike solid wastes, liquid wastes cannot be easily picked up and removed from an environment. Liquid wastes spread out, and easily pollute other sources of liquid if brought into contact. This type of waste also soaks into objects like soil and groundwater. This in turn carries over to pollute the plants, the animals in the ecosystem, as well as the humans within the area of the pollution.


title: Waste management

text: An important method of waste management is the prevention of waste material being created, also known as waste reduction. Waste Minimization is reducing the quantity of hazardous wastes achieved through a thorough application of innovative or alternative procedures. Methods of avoidance include reuse of second-hand products, repairing broken items instead of buying new ones, designing products to be refillable or reusable (such as cotton instead of plastic shopping bags), encouraging consumers to avoid using disposable products (such as disposable cutlery), removing any food/liquid remains from cans and packaging, and designing products that use less material to achieve the same purpose (for example, lightweighting of beverage cans).


title: Waste management

text: Areas with developing economies often experience exhausted waste collection services and inadequately managed and uncontrolled dumpsites. The problems are worsening. Problems with governance complicate the situation. Waste management in these countries and cities is an ongoing challenge due to weak institutions, chronic under-resourcing and rapid urbanization. All of these challenges, along with the lack of understanding of different factors that contribute to the hierarchy of waste management, affect the treatment of waste.


title: Waste management

text: In developing countries, waste management activities are usually carried by poor, for their survival. It has been estimated that 2% of population in Asia, Latin America and Africa are dependent on waste for their livelihood. Family organized, or individual manual scavengers are often involved with waste management practices with very little supportive network and facilities with increased risk of health effects. Additionally, this practice prevents their children from further education. Participation level of most citizens in waste management is very low, residents in urban areas are not actively involved in the process of waste management.


title: Waste management

text: Traditionally, the waste management industry has been a late adopter of new technologies such as RFID (Radio Frequency Identification) tags, GPS and integrated software packages which enable better quality data to be collected without the use of estimation or manual data entry. This technology has been used widely by many organizations in some industrialized countries. Radio frequency identification is a tagging system for automatic identification of recyclable components of municipal solid waste stream.


title: Waste management

text: Municipal solid waste generation shows spatiotemporal variation. In spatial distribution, the point sources in eastern coastal regions are quite different. Guangdong, Shanghai and Tianjin produced MSW of 30.35, 7.85 and 2.95 Mt, respectively. In temporal distribution, during 2009–2018, Fujian province showed 123% increase in MSW generation while Liaoning province showed only 7% increase, whereas Shanghai special zone had a decline of −11% after 2013. MSW composition characteristics is complicated. The major components such as kitchen waste, paper and rubber & plastics in different eastern coastal cities have fluctuation in the range of 52.8–65.3%, 3.5–11.9%, and 9.9–19.1%, respectively. Treatment rate of consumption waste is up to 99% with a sum of 52% landfill, 45% incineration, and 3% composting technologies, indicating that landfill still dominates MSW treatment.


title: Waste management

text: Morocco has seen benefits from implementing a $300 million sanitary landfill system. While it might appear to be a costly investment, the country's government predicts that it has saved them another $440 million in damages, or consequences of failing to dispose of waste properly.


title: Waste management

text: San Francisco started to make changes to their waste management policies in 2009 with the expectation to be zero waste by 2030. Council made changes such as making recycling and composting a mandatory practice for businesses and individuals, banning Styrofoam and plastic bags, putting charges on paper bags, and increasing garbage collection rates. Businesses are fiscally rewarded for correct disposal of recycling and composting and taxed for incorrect disposal. Besides these policies, the waste bins were manufactured in various sizes. The compost bin is the largest, the recycling bin is second, and the garbage bin is the smallest. This encourages individuals to sort their waste thoughtfully in respect to the sizes. These systems are working because they were able to divert 80% of waste from the landfill, which is the highest rate of any major U.S. city. Despite all these changes, Debbie Raphael, director of the San Francisco Department of the Environment, states that zero waste is still not achievable until all products are designed differently to be able to be recycled or compostable.


title: Waste management

text: Waste management policy in the United Kingdom is a responsibility of the Department of the Environment, Food and Rural Affairs (DEFRA). In England, the "Waste management plan for England" presents a compilation of waste management policies.


title: Waste management

text: In Zambia, ASAZA is a community-based organization whose principal purpose is to complement the efforts of Government and co-operating partners to uplift the standard of living for disadvantaged communities. The project's main objective is to minimize the problem of indiscriminate littering which leads to land degradation and pollution of the environment. ASAZA is also at the same time helping alleviate the problems of unemployment and poverty through income generation and payment of participants, women and unskilled youths.


title: Waste management

text: A record 53.6 million metric tonnes (Mt) of electronic waste was generated worldwide in 2019, up 21 per cent in just five years, according to the UN’s Global E-waste Monitor 2020, released today. The new report also predicts global e-waste – discarded products with a battery or plug – will reach 74 Mt by 2030, almost a doubling of e-waste in just 16 years. This makes e-waste the world’s fastest-growing domestic waste stream, fueled mainly by higher consumption rates of electric and electronic equipment, short life cycles, and few options for repair. Only 17.4 per cent of 2019’s e-waste was collected and recycled. This means that gold, silver, copper, platinum and other high-value, recoverable materials conservatively valued at US $57 billion – a sum greater than the Gross Domestic Product of most countries – were mostly dumped or burned rather than being collected for treatment and reuse.


title: Waste management

text: The Transboundary E-waste Flows Monitor quantified that 5.1 Mt (just below 10 percent of the total amount of global e-waste, 53.6 Mt) crossed country borders in 2019. To better understand the implication of transboundary movement, this study categorizes the transboundary movement of e-waste into controlled and uncontrolled movements and also considers both the receiving and sending regions.


title: Waste management

text: 1. Arrange to take your e-waste to a recycling firm like Great Lakes Electronics Corporation. The benefits of doing so are enormous.


title: Waste management

text: 2. Recycling remains the most effective way to keep e-waste from damaging our environment and our health.


title: Waste management

text: 3. The best thing you can do is to resist buying a new device until you really need it. Try to get your old product repaired if possible and if it can’t be fixed, resell or recycle it responsibly.


title: Waste management

text: 4. Before you recycle your device, seal up any broken parts in separate containers so that hazardous chemicals don’t leak. Wear latex gloves and a mask if you’re handling something that’s broken.


title: Esai Morales

text: Esai Manuel Morales Jr. (born October 1, 1962) is an American actor. He has had notable roles in the films "Bad Boys" with Sean Penn and "La Bamba" with Lou Diamond Phillips (1987). His television roles include the PBS 2002 drama series "American Family", the Showtime series "Resurrection Blvd." (2000–2002), portraying Lt. Tony Rodriguez on "NYPD Blue" (2001–2004), Joseph Adama in the science fiction series "Caprica" (2009–2010), Camino del Rio in the Netflix original series "Ozark" (2017) and as the DC Comics villain Deathstroke / Slade Wilson in the superhero series "Titans" (2018).


title: Esai Morales

text: Morales will appear as the main antagonist in the 2023 spy action film "" opposite Tom Cruise, a role which he will reprise in "" in 2024.


title: Esai Morales

text: Of Puerto Rican descent, Morales was born in Brooklyn, New York, to Esai Morales Sr., a welder, and Iris Margarita (née Declet), a union activist involved with the International Ladies' Garment Workers' Union. Morales began his pursuit of an acting career by attending the School of Performing Arts in Manhattan.


title: Esai Morales

text: His first professional performances were in theater and television in New York. His first major film was "Bad Boys" (1983), about rival teenagers sentenced to a juvenile correction facility. Morales appeared in a 1985 episode of the TV series "Fame". He co-starred with Burt Lancaster in the 1986 NBC miniseries "On Wings of Eagles", playing the Iranian Rashid, the hero of a true story about Ross Perot. Morales also appeared in "Miami Vice", "The Equalizer", and "24".


title: Esai Morales

text: He played Bob Morales, the real-life ex-convict and biker half-brother of 1950s rock and roll singer Ritchie Valens, in "La Bamba" (1987).


title: Esai Morales

text: Some of his other roles have reflected his socio-political interests, such as "The Burning Season" in 1994, "My Family/Mi Familia" in 1995, "The Disappearance of Garcia Lorca" (1997) and "Southern Cross" (1999). In the latter three films, as well as in others such as "Bloodhounds of Broadway" (1989) and "Rapa Nui" (1994), Morales saw increased amounts of screen time, starting with a role in the Pauly Shore film "In The Army Now" (1994). He portrayed a police officer in the film "Dogwatch" (1996) and Father Herrera in "The Virgin of Juarez" (2006).


title: Esai Morales

text: In the 1990s, he guest-starred on episodes of "The Outer Limits", "Tales from the Crypt", and two shorter-lived series, "L.A. Doctors" and "The Hunger". He appeared in a two-part episode of "Family Law" in 2000. He was part of the main cast of the long-running series "NYPD Blue" for three and a half seasons, from 2001 to 2004, as the head of the 15th precinct detective squad.


title: Esai Morales

text: He played a drug dealer named Lulu in the 2002 film "Paid in Full". In 2005, he was a voice actor in the video game "".


title: Esai Morales

text: Morales was cast in the film "American Fusion" (2005), and on June 19, 2006, he joined the cast of the Fox series "Vanished", as FBI agent Michael Tyner; the series ran for one season. In 2007, Morales appeared in an episode of the USA Network drama series "Burn Notice", as a Cuban shopkeeper being shaken down for "protection" money by local criminals. In early 2008, Morales had a role in the CBS drama "Jericho", as Major Edward Beck. He appeared in all seven episodes of the shortened That same year, he appeared in "Kill Kill Faster Faster", a film noir based on the novel of the same name by Joel Rose.


title: Esai Morales

text: In May 2008, it was announced that Morales would play the role of Joseph Adama in the science fiction television series "Caprica" – Syfy's prequel to the series "Battlestar Galactica". The series, though highly anticipated, only ran for one season in 2010. In 2009, he served as an official festival judge for the Noor Iranian Film Festival in Los Angeles.


title: Esai Morales

text: In 2011, Morales starred in the drama film "Gun Hill Road" as Enrique, and in the web drama "Los Americans" airing on PIC.tv. and Morales worked with Tony Plana, Yvonne DeLaRosa, Lupe Ontiveros, and JC Gonzalez in "Los Americans", an Internet program launched in May 2011.


title: Esai Morales

text: In March 2015, Robert Rodriguez cast him as Lord Amancio Malvado for the second season of horror series "", which was followed in 2017 by a main role in the first season of the Netflix original series "Ozark", and then in 2019 in an antagonist role for the second season of the DC Universe superhero series "Titans" as Slade Wilson / Deathstroke.


title: Esai Morales

text: On May 21, 2020, Morales was officially confirmed to be starring in "" as the film's villain, a role which he is reprising in the .


title: Esai Morales

text: In 2005, Morales (along with Mercedes Ruehl) received the Rita Moreno HOLA Award for Excellence from the Hispanic Organization of Latin Actors (HOLA).


title: Esai Morales

text: He received the Lifetime Achievement Award from the Arpa Foundation for his impact as an actor and role model.


title: Esai Morales

text: Morales has described himself as an "actorvist", primarily as one of the founders of the "National Hispanic Foundation for the Arts", taking inspiration from his mother, who was an organizer for the International Ladies' Garment Workers' Union. He is also interested in environmental issues and was a founding board member of E.C.O. (Earth Communications Office).


title: Esai Morales

text: In a February 28, 2007, all-star benefit reading of "The Gift of Peace" at UCLA's Freud Playhouse, he portrayed a hopeful member of a struggling immigrant family. The play was an open appeal and fundraiser for passage of U.S. House Resolution 808, which sought to establish a Cabinet-level "Department of Peace" in the U.S. government, to be funded by a two percent diversion of the Pentagon's annual budget.


title: Esai Morales

text: Morales' first name is frequently used in crossword puzzles, because its rare construction makes it a prize for crossword constructors (it is a four-letter word in English that is 75 percent vowels, including the first and last letters). One crossword clue website estimated that between 1994 and 2016, "ESAI" had been used as a crossword answer over 100 times in American papers such as "The Los Angeles Times", "The New York Times", and "The Washington Post".


title: Gamma ray

text: A gamma ray, also known as gamma radiation (symbol γ or formula_1), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically shorter than those of X-rays. With frequencies above 30 exahertz (), it imparts the highest photon energy. Paul Villard, a French chemist and physicist, discovered gamma radiation in 1900 while studying radiation emitted by radium. In 1903, Ernest Rutherford named this radiation "gamma rays" based on their relatively strong penetration of matter; in 1900 he had already named two less penetrating types of decay radiation (discovered by Henri Becquerel) alpha rays and beta rays in ascending order of penetrating power.


title: Gamma ray

text: Gamma rays from radioactive decay are in the energy range from a few kiloelectronvolts (keV) to approximately 8 megaelectronvolts (MeV), corresponding to the typical energy levels in nuclei with reasonably long lifetimes. The energy spectrum of gamma rays can be used to identify the decaying radionuclides using gamma spectroscopy. Very-high-energy gamma rays in the 100–1000 teraelectronvolt (TeV) range have been observed from sources such as the Cygnus X-3 microquasar.


title: Gamma ray

text: Natural sources of gamma rays originating on Earth are mostly a result of radioactive decay and secondary radiation from atmospheric interactions with cosmic ray particles. However, there are other rare natural sources, such as terrestrial gamma-ray flashes, which produce gamma rays from electron action upon the nucleus. Notable artificial sources of gamma rays include fission, such as that which occurs in nuclear reactors, and high energy physics experiments, such as neutral pion decay and nuclear fusion.


title: Gamma ray

text: Gamma rays and X-rays are both electromagnetic radiation, and since they overlap in the electromagnetic spectrum, the terminology varies between scientific disciplines. In some fields of physics, they are distinguished by their origin: Gamma rays are created by nuclear decay while X-rays originate outside the nucleus. In astrophysics, gamma rays are conventionally defined as having photon energies above 100 keV and are the subject of gamma ray astronomy, while radiation below 100 keV is classified as X-rays and is the subject of X-ray astronomy.


title: Gamma ray

text: Gamma rays are ionizing radiation and are thus hazardous to life. Due to their high penetration power, they can damage bone marrow and internal organs. Unlike alpha and beta rays, they easily pass through the body and thus pose a formidable radiation protection challenge, requiring shielding made from dense materials such as lead or concrete. On Earth, the magnetosphere protects life from most types of lethal cosmic radiation other than gamma rays, which are absorbed by 0.53 bars of atmosphere as they penetrate the atmosphere.


title: Gamma ray

text: Gamma rays cannot be reflected by a mirror and their wavelengths are so small that they will pass between the atoms in a detector.


title: Gamma ray

text: The first gamma ray source to be discovered was the radioactive decay process called "gamma decay". In this type of decay, an excited nucleus emits a gamma ray almost immediately upon formation. Paul Villard, a French chemist and physicist, discovered gamma radiation in 1900, while studying radiation emitted from radium. Villard knew that his described radiation was more powerful than previously described types of rays from radium, which included beta rays, first noted as "radioactivity" by Henri Becquerel in 1896, and alpha rays, discovered as a less penetrating form of radiation by Rutherford, in 1899. However, Villard did not consider naming them as a different fundamental type. Later, in 1903, Villard's radiation was recognized as being of a type fundamentally different from previously named rays by Ernest Rutherford, who named Villard's rays "gamma rays" by analogy with the beta and alpha rays that Rutherford had differentiated in 1899. The "rays" emitted by radioactive elements were named in order of their power to penetrate various materials, using the first three letters of the Greek alphabet: alpha rays as the least penetrating, followed by beta rays, followed by gamma rays as the most penetrating. Rutherford also noted that gamma rays were not deflected (or at least, not deflected) by a magnetic field, another property making them unlike alpha and beta rays.


title: Gamma ray

text: Gamma rays were first thought to be particles with mass, like alpha and beta rays. Rutherford initially believed that they might be extremely fast beta particles, but their failure to be deflected by a magnetic field indicated that they had no charge. In 1914, gamma rays were observed to be reflected from crystal surfaces, proving that they were electromagnetic radiation. Rutherford and his co-worker Edward Andrade measured the wavelengths of gamma rays from radium, and found they were similar to X-rays, but with shorter wavelengths and thus, higher frequency. This was eventually recognized as giving them more energy per photon, as soon as the latter term became generally accepted. A gamma decay was then understood to usually emit a gamma photon.


title: Gamma ray

text: Natural sources of gamma rays on Earth include gamma decay from naturally occurring radioisotopes such as potassium-40, and also as a secondary radiation from various atmospheric interactions with cosmic ray particles. Some rare terrestrial natural sources that produce gamma rays that are not of a nuclear origin, are lightning strikes and terrestrial gamma-ray flashes, which produce high energy emissions from natural high-energy voltages. Gamma rays are produced by a number of astronomical processes in which very high-energy electrons are produced. Such electrons produce secondary gamma rays by the mechanisms of "bremsstrahlung", inverse Compton scattering and synchrotron radiation. A large fraction of such astronomical gamma rays are screened by Earth's atmosphere. Notable artificial sources of gamma rays include fission, such as occurs in nuclear reactors, as well as high energy physics experiments, such as neutral pion decay and nuclear fusion.


title: Gamma ray

text: A sample of gamma ray-emitting material that is used for irradiating or imaging is known as a gamma source. It is also called a radioactive source, isotope source, or radiation source, though these more general terms also apply to alpha and beta-emitting devices. Gamma sources are usually sealed to prevent radioactive contamination, and transported in heavy shielding.


title: Gamma ray

text: Gamma rays are produced during gamma decay, which normally occurs after other forms of decay occur, such as alpha or beta decay. A radioactive nucleus can decay by the emission of an or particle. The daughter nucleus that results is usually left in an excited state. It can then decay to a lower energy state by emitting a gamma ray photon, in a process called gamma decay.


title: Gamma ray

text: The emission of a gamma ray from an excited nucleus typically requires only 10 seconds. Gamma decay may also follow nuclear reactions such as neutron capture, nuclear fission, or nuclear fusion. Gamma decay is also a mode of relaxation of many excited states of atomic nuclei following other types of radioactive decay, such as beta decay, so long as these states possess the necessary component of nuclear spin. When high-energy gamma rays, electrons, or protons bombard materials, the excited atoms emit characteristic "secondary" gamma rays, which are products of the creation of excited nuclear states in the bombarded atoms. Such transitions, a form of nuclear gamma fluorescence, form a topic in nuclear physics called gamma spectroscopy. Formation of fluorescent gamma rays are a rapid subtype of radioactive gamma decay.


title: Gamma ray

text: In certain cases, the excited nuclear state that follows the emission of a beta particle or other type of excitation, may be more stable than average, and is termed a metastable excited state, if its decay takes (at least) 100 to 1000 times longer than the average 10 seconds. Such relatively long-lived excited nuclei are termed nuclear isomers, and their decays are termed isomeric transitions. Such nuclei have half-lifes that are more easily measurable, and rare nuclear isomers are able to stay in their excited state for minutes, hours, days, or occasionally far longer, before emitting a gamma ray. The process of isomeric transition is therefore similar to any gamma emission, but differs in that it involves the intermediate metastable excited state(s) of the nuclei. Metastable states are often characterized by high nuclear spin, requiring a change in spin of several units or more with gamma decay, instead of a single unit transition that occurs in only 10 seconds. The rate of gamma decay is also slowed when the energy of excitation of the nucleus is small.


title: Gamma ray

text: An emitted gamma ray from any type of excited state may transfer its energy directly to any electrons, but most probably to one of the K shell electrons of the atom, causing it to be ejected from that atom, in a process generally termed the photoelectric effect (external gamma rays and ultraviolet rays may also cause this effect). The photoelectric effect should not be confused with the internal conversion process, in which a gamma ray photon is not produced as an intermediate particle (rather, a "virtual gamma ray" may be thought to mediate the process).


title: Gamma ray

text: One example of gamma ray production due to radionuclide decay is the decay scheme for cobalt-60, as illustrated in the accompanying diagram. First, decays to excited by beta decay emission of an electron of . Then the excited decays to the ground state (see nuclear shell model) by emitting gamma rays in succession of 1.17 MeV followed by . This path is followed 99.88% of the time:


title: Gamma ray

text: Another example is the alpha decay of to form ; which is followed by gamma emission. In some cases, the gamma emission spectrum of the daughter nucleus is quite simple, (e.g. /) while in other cases, such as with (/ and /), the gamma emission spectrum is complex, revealing that a series of nuclear energy levels exist.


title: Gamma ray

text: Gamma rays are produced in many processes of particle physics. Typically, gamma rays are the products of neutral systems which decay through electromagnetic interactions (rather than a weak or strong interaction). For example, in an electron–positron annihilation, the usual products are two gamma ray photons. If the annihilating electron and positron are at rest, each of the resulting gamma rays has an energy of ~ 511 keV and frequency of ~ . Similarly, a neutral pion most often decays into two photons. Many other hadrons and massive bosons also decay electromagnetically. High energy physics experiments, such as the Large Hadron Collider, accordingly employ substantial radiation shielding. Because subatomic particles mostly have far shorter wavelengths than atomic nuclei, particle physics gamma rays are generally several orders of magnitude more energetic than nuclear decay gamma rays. Since gamma rays are at the top of the electromagnetic spectrum in terms of energy, all extremely high-energy photons are gamma rays; for example, a photon having the Planck energy would be a gamma ray.


title: Gamma ray

text: A few gamma rays in astronomy are known to arise from gamma decay (see discussion of SN1987A), but most do not.


title: Gamma ray

text: Photons from astrophysical sources that carry energy in the gamma radiation range are often explicitly called gamma-radiation. In addition to nuclear emissions, they are often produced by sub-atomic particle and particle-photon interactions. Those include electron-positron annihilation, neutral pion decay, bremsstrahlung, inverse Compton scattering, and synchrotron radiation.


title: Gamma ray

text: In October 2017, scientists from various European universities proposed a means for sources of GeV photons using lasers as exciters through a controlled interplay between the cascade and anomalous radiative trapping.


title: Gamma ray

text: Thunderstorms can produce a brief pulse of gamma radiation called a terrestrial gamma-ray flash. These gamma rays are thought to be produced by high intensity static electric fields accelerating electrons, which then produce gamma rays by bremsstrahlung as they collide with and are slowed by atoms in the atmosphere. Gamma rays up to 100 MeV can be emitted by terrestrial thunderstorms, and were discovered by space-borne observatories. This raises the possibility of health risks to passengers and crew on aircraft flying in or near thunderclouds.


title: Gamma ray

text: The most effusive solar flares emit across the entire EM spectrum, including γ-rays. The first confident observation occurred in 1972.


title: Gamma ray

text: Extraterrestrial, high energy gamma rays include the gamma ray background produced when cosmic rays (either high speed electrons or protons) collide with ordinary matter, producing pair-production gamma rays at 511 keV. Alternatively, bremsstrahlung are produced at energies of tens of MeV or more when cosmic ray electrons interact with nuclei of sufficiently high atomic number (see gamma ray image of the Moon near the end of this article, for illustration).


title: Gamma ray

text: The gamma ray sky (see illustration at right) is dominated by the more common and longer-term production of gamma rays that emanate from pulsars within the Milky Way. Sources from the rest of the sky are mostly quasars. Pulsars are thought to be neutron stars with magnetic fields that produce focused beams of radiation, and are far less energetic, more common, and much nearer sources (typically seen only in our own galaxy) than are quasars or the rarer gamma-ray burst sources of gamma rays. Pulsars have relatively long-lived magnetic fields that produce focused beams of relativistic speed charged particles, which emit gamma rays (bremsstrahlung) when those strike gas or dust in their nearby medium, and are decelerated. This is a similar mechanism to the production of high-energy photons in megavoltage radiation therapy machines (see bremsstrahlung). Inverse Compton scattering, in which charged particles (usually electrons) impart energy to low-energy photons boosting them to higher energy photons. Such impacts of photons on relativistic charged particle beams is another possible mechanism of gamma ray production. Neutron stars with a very high magnetic field (magnetars), thought to produce astronomical soft gamma repeaters, are another relatively long-lived star-powered source of gamma radiation.


title: Gamma ray

text: More powerful gamma rays from very distant quasars and closer active galaxies are thought to have a gamma ray production source similar to a particle accelerator. High energy electrons produced by the quasar, and subjected to inverse Compton scattering, synchrotron radiation, or bremsstrahlung, are the likely source of the gamma rays from those objects. It is thought that a supermassive black hole at the center of such galaxies provides the power source that intermittently destroys stars and focuses the resulting charged particles into beams that emerge from their rotational poles. When those beams interact with gas, dust, and lower energy photons they produce X-rays and gamma rays. These sources are known to fluctuate with durations of a few weeks, suggesting their relatively small size (less than a few light-weeks across). Such sources of gamma and X-rays are the most commonly visible high intensity sources outside our galaxy. They shine not in bursts (see illustration), but relatively continuously when viewed with gamma ray telescopes. The power of a typical quasar is about 10 watts, a small fraction of which is gamma radiation. Much of the rest is emitted as electromagnetic waves of all frequencies, including radio waves.


title: Gamma ray

text: The most intense sources of gamma rays, are also the most intense sources of any type of electromagnetic radiation presently known. They are the "long duration burst" sources of gamma rays in astronomy ("long" in this context, meaning a few tens of seconds), and they are rare compared with the sources discussed above. By contrast, "short" gamma-ray bursts of two seconds or less, which are not associated with supernovae, are thought to produce gamma rays during the collision of pairs of neutron stars, or a neutron star and a black hole.


title: Gamma ray

text: The so-called "long-duration" gamma-ray bursts produce a total energy output of about 10 joules (as much energy as our Sun will produce in its entire life-time) but in a period of only 20 to 40 seconds. Gamma rays are approximately 50% of the total energy output. The leading hypotheses for the mechanism of production of these highest-known intensity beams of radiation, are inverse Compton scattering and synchrotron radiation from high-energy charged particles. These processes occur as relativistic charged particles leave the region of the event horizon of a newly formed black hole created during supernova explosion. The beam of particles moving at relativistic speeds are focused for a few tens of seconds by the magnetic field of the exploding hypernova. The fusion explosion of the hypernova drives the energetics of the process. If the narrowly directed beam happens to be pointed toward the Earth, it shines at gamma ray frequencies with such intensity, that it can be detected even at distances of up to 10 billion light years, which is close to the edge of the visible universe.


title: Gamma ray

text: Due to their penetrating nature, gamma rays require large amounts of shielding mass to reduce them to levels which are not harmful to living cells, in contrast to alpha particles, which can be stopped by paper or skin, and beta particles, which can be shielded by thin aluminium. Gamma rays are best absorbed by materials with high atomic numbers ("Z") and high density, which contribute to the total stopping power. Because of this, a lead (high "Z") shield is 20–30% better as a gamma shield than an equal mass of another low-"Z" shielding material, such as aluminium, concrete, water, or soil; lead's major advantage is not in lower weight, but rather its compactness due to its higher density. Protective clothing, goggles and respirators can protect from internal contact with or ingestion of alpha or beta emitting particles, but provide no protection from gamma radiation from external sources.


title: Gamma ray

text: The higher the energy of the gamma rays, the thicker the shielding made from the same shielding material is required. Materials for shielding gamma rays are typically measured by the thickness required to reduce the intensity of the gamma rays by one half (the half value layer or HVL). For example, gamma rays that require 1 cm (0.4 inch) of lead to reduce their intensity by 50% will also have their intensity reduced in half by of granite rock, 6 cm (2.5 inches) of concrete, or 9 cm (3.5 inches) of packed soil. However, the mass of this much concrete or soil is only 20–30% greater than that of lead with the same absorption capability. Depleted uranium is used for shielding in portable gamma ray sources, but here the savings in weight over lead are larger, In a nuclear power plant, shielding can be provided by steel and concrete in the pressure and particle containment vessel, while water provides a radiation shielding of fuel rods during storage or transport into the reactor core. The loss of water or removal of a "hot" fuel assembly into the air would result in much higher radiation levels than when kept under water.


title: Gamma ray

text: When a gamma ray passes through matter, the probability for absorption is proportional to the thickness of the layer, the density of the material, and the absorption cross section of the material. The total absorption shows an exponential decrease of intensity with distance from the incident surface:


title: Gamma ray

text: where x is the thickness of the material from the incident surface, μ= "n"σ is the absorption coefficient, measured in cm, "n" the number of atoms per cm of the material (atomic density) and σ the absorption cross section in cm.


title: Gamma ray

text: The secondary electrons (and/or positrons) produced in any of these three processes frequently have enough energy to produce much ionization themselves.


title: Gamma ray

text: Additionally, gamma rays, particularly high energy ones, can interact with atomic nuclei resulting in ejection of particles in photodisintegration, or in some cases, even nuclear fission (photofission).


title: Gamma ray

text: High-energy (from 80 GeV to ~10 TeV) gamma rays arriving from far-distant quasars are used to estimate the extragalactic background light in the universe: The highest-energy rays interact more readily with the background light photons and thus the density of the background light may be estimated by analyzing the incoming gamma ray spectra.


title: Gamma ray

text: Gamma spectroscopy is the study of the energetic transitions in atomic nuclei, which are generally associated with the absorption or emission of gamma rays. As in optical spectroscopy (see Franck–Condon effect) the absorption of gamma rays by a nucleus is especially likely (i.e., peaks in a "resonance") when the energy of the gamma ray is the same as that of an energy transition in the nucleus. In the case of gamma rays, such a resonance is seen in the technique of Mössbauer spectroscopy. In the Mössbauer effect the narrow resonance absorption for nuclear gamma absorption can be successfully attained by physically immobilizing atomic nuclei in a crystal. The immobilization of nuclei at both ends of a gamma resonance interaction is required so that no gamma energy is lost to the kinetic energy of recoiling nuclei at either the emitting or absorbing end of a gamma transition. Such loss of energy causes gamma ray resonance absorption to fail. However, when emitted gamma rays carry essentially all of the energy of the atomic nuclear de-excitation that produces them, this energy is also sufficient to excite the same energy state in a second immobilized nucleus of the same type.


title: Gamma ray

text: Gamma rays provide information about some of the most energetic phenomena in the universe; however, they are largely absorbed by the Earth's atmosphere. Instruments aboard high-altitude balloons and satellites missions, such as the Fermi Gamma-ray Space Telescope, provide our only view of the universe in gamma rays.


title: Gamma ray

text: Gamma-induced molecular changes can also be used to alter the properties of semi-precious stones, and is often used to change white topaz into blue topaz.


title: Gamma ray

text: Non-contact industrial sensors commonly use sources of gamma radiation in refining, mining, chemicals, food, soaps and detergents, and pulp and paper industries, for the measurement of levels, density, and thicknesses. Gamma-ray sensors are also used for measuring the fluid levels in water and oil industries. Typically, these use Co-60 or Cs-137 isotopes as the radiation source.


title: Gamma ray

text: In the US, gamma ray detectors are beginning to be used as part of the Container Security Initiative (CSI). These machines are advertised to be able to scan 30 containers per hour.


title: Gamma ray

text: Gamma radiation is often used to kill living organisms, in a process called irradiation. Applications of this include the sterilization of medical equipment (as an alternative to autoclaves or chemical means), the removal of decay-causing bacteria from many foods and the prevention of the sprouting of fruit and vegetables to maintain freshness and flavor.


title: Gamma ray

text: Despite their cancer-causing properties, gamma rays are also used to treat some types of cancer, since the rays also kill cancer cells. In the procedure called gamma-knife surgery, multiple concentrated beams of gamma rays are directed to the growth in order to kill the cancerous cells. The beams are aimed from different angles to concentrate the radiation on the growth while minimizing damage to surrounding tissues.


title: Gamma ray

text: Gamma rays are also used for diagnostic purposes in nuclear medicine in imaging techniques. A number of different gamma-emitting radioisotopes are used. For example, in a PET scan a radiolabeled sugar called fluorodeoxyglucose emits positrons that are annihilated by electrons, producing pairs of gamma rays that highlight cancer as the cancer often has a higher metabolic rate than the surrounding tissues. The most common gamma emitter used in medical applications is the nuclear isomer technetium-99m which emits gamma rays in the same energy range as diagnostic X-rays. When this radionuclide tracer is administered to a patient, a gamma camera can be used to form an image of the radioisotope's distribution by detecting the gamma radiation emitted (see also SPECT). Depending on which molecule has been labeled with the tracer, such techniques can be employed to diagnose a wide range of conditions (for example, the spread of cancer to the bones via bone scan).


title: Gamma ray

text: Gamma rays cause damage at a cellular level and are penetrating, causing diffuse damage throughout the body. However, they are less ionising than alpha or beta particles, which are less penetrating.


title: Gamma ray

text: Low levels of gamma rays cause a stochastic health risk, which for radiation dose assessment is defined as the "probability" of cancer induction and genetic damage. High doses produce deterministic effects, which is the "severity" of acute tissue damage that is certain to happen. These effects are compared to the physical quantity absorbed dose measured by the unit gray (Gy).


title: Gamma ray

text: When gamma radiation breaks DNA molecules, a cell may be able to repair the damaged genetic material, within limits. However, a study of Rothkamm and Lobrich has shown that this repair process works well after high-dose exposure but is much slower in the case of a low-dose exposure.


title: Gamma ray

text: The natural outdoor exposure in the United Kingdom ranges from 0.1 to 0.5 µSv/h with significant increase around known nuclear and contaminated sites. Natural exposure to gamma rays is about 1 to 2 mSv per year, and the average total amount of radiation received in one year per inhabitant in the USA is 3.6 mSv. There is a small increase in the dose, due to naturally occurring gamma radiation, around small particles of high atomic number materials in the human body caused by the photoelectric effect.


title: Gamma ray

text: By comparison, the radiation dose from chest radiography (about 0.06 mSv) is a fraction of the annual naturally occurring background radiation dose. A chest CT delivers 5 to 8 mSv. A whole-body PET/CT scan can deliver 14 to 32 mSv depending on the protocol. The dose from fluoroscopy of the stomach is much higher, approximately 50 mSv (14 times the annual background).


title: Gamma ray

text: An acute full-body equivalent single exposure dose of 1 Sv (1000 mSv) causes slight blood changes, but 2.0–3.5 Sv (2.0–3.5 Gy) causes very severe syndrome of nausea, hair loss, and hemorrhaging, and will cause death in a sizable number of cases—-about 10% to 35% without medical treatment. A dose of 5 Sv (5 Gy) is considered approximately the LD (lethal dose for 50% of exposed population) for an acute exposure to radiation even with standard medical treatment. A dose higher than 5 Sv (5 Gy) brings an increasing chance of death above 50%. Above 7.5–10 Sv (7.5–10 Gy) to the entire body, even extraordinary treatment, such as bone-marrow transplants, will not prevent the death of the individual exposed (see radiation poisoning). (Doses much larger than this may, however, be delivered to selected parts of the body in the course of radiation therapy.)


title: Gamma ray

text: For low-dose exposure, for example among nuclear workers, who receive an average yearly radiation dose of 19 mSv, the risk of dying from cancer (excluding leukemia) increases by 2 percent. For a dose of 100 mSv, the risk increase is 10 percent. By comparison, risk of dying from cancer was increased by 32 percent for the survivors of the atomic bombing of Hiroshima and Nagasaki.


title: Gamma ray

text: The measure of the ionizing effect of gamma and X-rays in dry air is called the exposure, for which a legacy unit, the röntgen was used from 1928. This has been replaced by kerma, now mainly used for instrument calibration purposes but not for received dose effect. The effect of gamma and other ionizing radiation on living tissue is more closely related to the amount of energy deposited in tissue rather than the ionisation of air, and replacement radiometric units and quantities for radiation protection have been defined and developed from 1953 onwards. These are:


title: Gamma ray

text: The conventional distinction between X-rays and gamma rays has changed over time. Originally, the electromagnetic radiation emitted by X-ray tubes almost invariably had a longer wavelength than the radiation (gamma rays) emitted by radioactive nuclei. Older literature distinguished between X- and gamma radiation on the basis of wavelength, with radiation shorter than some arbitrary wavelength, such as 10 m, defined as gamma rays. Since the energy of photons is proportional to their frequency and inversely proportional to wavelength, this past distinction between X-rays and gamma rays can also be thought of in terms of its energy, with gamma rays considered to be higher energy electromagnetic radiation than are X-rays.


title: Gamma ray

text: However, since current artificial sources are now able to duplicate any electromagnetic radiation that originates in the nucleus, as well as far higher energies, the wavelengths characteristic of radioactive gamma ray sources vs. other types now completely overlap. Thus, gamma rays are now usually distinguished by their origin: X-rays are emitted by definition by electrons outside the nucleus, while gamma rays are emitted by the nucleus. Exceptions to this convention occur in astronomy, where gamma decay is seen in the afterglow of certain supernovas, but radiation from high energy processes known to involve other radiation sources than radioactive decay is still classed as gamma radiation.


title: Gamma ray

text: For example, modern high-energy X-rays produced by linear accelerators for megavoltage treatment in cancer often have higher energy (4 to 25 MeV) than do most classical gamma rays produced by nuclear gamma decay. One of the most common gamma ray emitting isotopes used in diagnostic nuclear medicine, technetium-99m, produces gamma radiation of the same energy (140 keV) as that produced by diagnostic X-ray machines, but of significantly lower energy than therapeutic photons from linear particle accelerators. In the medical community today, the convention that radiation produced by nuclear decay is the only type referred to as "gamma" radiation is still respected.


title: Gamma ray

text: Due to this broad overlap in energy ranges, in physics the two types of electromagnetic radiation are now often defined by their origin: X-rays are emitted by electrons (either in orbitals outside of the nucleus, or while being accelerated to produce bremsstrahlung-type radiation), while gamma rays are emitted by the nucleus or by means of other particle decays or annihilation events. There is no lower limit to the energy of photons produced by nuclear reactions, and thus ultraviolet or lower energy photons produced by these processes would also be defined as "gamma rays". The only naming-convention that is still universally respected is the rule that electromagnetic radiation that is known to be of atomic nuclear origin is "always" referred to as "gamma rays", and never as X-rays. However, in physics and astronomy, the converse convention (that all gamma rays are considered to be of nuclear origin) is frequently violated.


title: Gamma ray

text: In astronomy, higher energy gamma and X-rays are defined by energy, since the processes that produce them may be uncertain and photon energy, not origin, determines the required astronomical detectors needed. High-energy photons occur in nature that are known to be produced by processes other than nuclear decay but are still referred to as gamma radiation. An example is "gamma rays" from lightning discharges at 10 to 20 MeV, and known to be produced by the bremsstrahlung mechanism.


title: Gamma ray

text: Another example is gamma-ray bursts, now known to be produced from processes too powerful to involve simple collections of atoms undergoing radioactive decay. This is part and parcel of the general realization that many gamma rays produced in astronomical processes result not from radioactive decay or particle annihilation, but rather in non-radioactive processes similar to X-rays. Although the gamma rays of astronomy often come from non-radioactive events, a few gamma rays in astronomy are specifically known to originate from gamma decay of nuclei (as demonstrated by their spectra and emission half life). A classic example is that of supernova SN 1987A, which emits an "afterglow" of gamma-ray photons from the decay of newly made radioactive nickel-56 and cobalt-56. Most gamma rays in astronomy, however, arise by other mechanisms.


title: Grape

text: A grape is a fruit, botanically a berry, of the deciduous woody vines of the flowering plant genus "Vitis". Grapes are a non-climacteric type of fruit, generally occurring in clusters.


title: Grape

text: The cultivation of grapes began perhaps 8,000 years ago, and the fruit has been used as human food over history. Eaten fresh or in dried form (as raisins, currants and sultanas), grapes also hold cultural significance in many parts of the world, particularly for their role in winemaking. Other grape-derived products include various types of jam, juice, vinegar and oil.


title: Grape

text: The Middle East is generally described as the homeland of grape and the cultivation of this plant began there 6,000–8,000 years ago. Yeast, one of the earliest domesticated microorganisms, occurs naturally on the skins of grapes, leading to the discovery of alcoholic drinks such as wine. The earliest archeological evidence for a dominant position of wine-making in human culture dates from 8,000 years ago in Georgia.


title: Grape

text: The oldest known winery was found in Armenia, dating to around 4000 BC. By the 9th century AD, the city of Shiraz was known to produce some of the finest wines in the Middle East. Thus it has been proposed that Syrah red wine is named after Shiraz, a city in Persia where the grape was used to make Shirazi wine.


title: Grape

text: Ancient Egyptian hieroglyphics record the cultivation of purple grapes, and history attests to the ancient Greeks, Cypriots, Phoenicians, and Romans growing purple grapes both for eating and wine production. The growing of grapes would later spread to other regions in Europe, as well as North Africa, and eventually in North America.


title: Grape

text: In 2005 a team of archaeologists concluded that some Chalcolithic wine jars, which were discovered in Cyprus in the 1930s, were the oldest of their kind in the world, dating back to 3,500 BC. Moreover, Commandaria, a sweet dessert wine from Cyprus, is the oldest manufactured wine in the world, its origins traced as far back as 2000 BC.


title: Grape

text: In North America, native grapes belonging to various species of the genus "Vitis" proliferate in the wild across the continent, and were a part of the diet of many Native Americans, but were considered by early European colonists to be unsuitable for wine. In the 19th century, Ephraim Bull of Concord, Massachusetts, cultivated seeds from wild "Vitis labrusca" vines to create the Concord grape which would become an important agricultural crop in the United States.


title: Grape

text: Grapes are a type of fruit that grow in clusters of 15 to 300, and can be crimson, black, dark blue, yellow, green, orange, and pink. "White" grapes are actually green in color, and are evolutionarily derived from the purple grape. Mutations in two regulatory genes of white grapes turn off production of anthocyanins, which are responsible for the color of purple grapes. Anthocyanins and other pigment chemicals of the larger family of polyphenols in purple grapes are responsible for the varying shades of purple in red wines. Grapes are typically an ellipsoid shape resembling a prolate spheroid.


title: Grape

text: Raw grapes are 81% water, 18% carbohydrates, 1% protein, and have negligible fat (table). A reference amount of raw grapes supplies of food energy and a moderate amount of vitamin K (14% of the Daily Value), with no other micronutrients in significant content.


title: Grape

text: Most domesticated grapes come from cultivars of "Vitis vinifera", a grapevine native to the Mediterranean and Central Asia. Minor amounts of fruit and wine come from American and Asian species such as:


title: Grape

text: According to the Food and Agriculture Organization (FAO), 75,866 square kilometers of the world are dedicated to grapes. Approximately 71% of world grape production is used for wine, 27% as fresh fruit, and 2% as dried fruit. A portion of grape production goes to producing grape juice to be reconstituted for fruits canned "with no added sugar" and "100% natural". The area dedicated to vineyards is increasing by about 2% per year.


title: Grape

text: There are no reliable statistics that break down grape production by variety. It is believed that the most widely planted variety is Sultana, also known as Thompson Seedless, with at least 3,600 km (880,000 acres) dedicated to it. The second most common variety is Airén. Other popular varieties include Cabernet Sauvignon, Sauvignon blanc, Cabernet Franc, Merlot, Grenache, Tempranillo, Riesling, and Chardonnay.


title: Grape

text: Commercially cultivated grapes can usually be classified as either table or wine grapes, based on their intended method of consumption: eaten raw (table grapes) or used to make wine (wine grapes). While almost all of them belong to the same species, "Vitis vinifera", table and wine grapes have significant differences, brought about through selective breeding. Table grape cultivars tend to have large, seedless fruit (see below) with relatively thin skin. Wine grapes are smaller, usually seeded, and have relatively thick skins (a desirable characteristic in winemaking, since much of the aroma in wine comes from the skin). Wine grapes also tend to be very sweet: they are harvested at the time when their juice is approximately 24% sugar by weight. By comparison, commercially produced "100% grape juice", made from table grapes, is usually around 15% sugar by weight.


title: Grape

text: Seedless cultivars now make up the overwhelming majority of table grape plantings. Because grapevines are vegetatively propagated by cuttings, the lack of seeds does not present a problem for reproduction. It is an issue for breeders, who must either use a seeded variety as the female parent or rescue embryos early in development using tissue culture techniques.


title: Grape

text: There are several sources of the seedlessness trait, and essentially all commercial cultivators get it from one of three sources: Thompson Seedless, Russian Seedless, and Black Monukka, all being cultivars of "Vitis vinifera". There are currently more than a dozen varieties of seedless grapes. Several, such as Einset Seedless, Benjamin Gunnels's Prime seedless grapes, Reliance, and Venus, have been specifically cultivated for hardiness and quality in the relatively cold climates of northeastern United States and southern Ontario.


title: Grape

text: An offset to the improved eating quality of seedlessness is the loss of potential health benefits provided by the enriched phytochemical content of grape seeds (see Health claims, below).


title: Grape

text: In most of Europe and North America, dried grapes are referred to as "raisins" or the local equivalent. In the UK, three different varieties are recognized, forcing the EU to use the term "dried vine fruit" in official documents.


title: Grape

text: A "raisin" is any dried grape. While "raisin" is a French loanword, the word in French refers to the fresh fruit; "grappe" (from which the English "grape" is derived) refers to the bunch (as in "une grappe de raisins"). A raisin in French is called "raisin sec" ("dry grape").


title: Grape

text: A "currant" is a dried Zante Black Corinth grape, the name being a corruption of the French "raisin de Corinthe" (Corinth grape). The names of the black and red currant, now more usually blackcurrant and redcurrant, two berries unrelated to grapes, are derived from this use. Some other fruits of similar appearance are also so named, for example, Australian currant, native currant, Indian currant.


title: Grape

text: A "sultana" was originally a raisin made from Sultana grapes of Turkish origin (known as Thompson Seedless in the United States), but the word is now applied to raisins made from either white grapes or red grapes that are bleached to resemble the traditional sultana.


title: Grape

text: Grape juice is obtained from crushing and blending grapes into a liquid. The juice is often sold in stores or fermented and made into wine, brandy, or vinegar. Grape juice that has been pasteurized, removing any naturally occurring yeast, will not ferment if kept sterile, and thus contains no alcohol. In the wine industry, grape juice that contains 7–23% of pulp, skins, stems and seeds is often referred to as "must". In North America, the most common grape juice is purple and made from Concord grapes, while white grape juice is commonly made from Niagara grapes, both of which are varieties of grapes, a different species from European wine grapes. In California, Sultana (known there as Thompson Seedless) grapes are sometimes diverted from the raisin or table market to produce white juice.


title: Grape

text: Winemaking from red and white grape flesh and skins produces substantial quantities of organic residues, collectively called pomace (also "marc"), which includes crushed skins, seeds, stems, and leaves generally used as compost. Grape pomace – some 10-30% of the total mass of grapes crushed – contains various phytochemicals, such as unfermented sugars, alcohol, polyphenols, tannins, anthocyanins, and numerous other compounds, some of which are harvested and extracted for commercial applications (a process sometimes called "valorization" of the pomace).


title: Grape

text: Anthocyanins tend to be the main polyphenolics in purple grapes, whereas flavan-3-ols (i.e. catechins) are the more abundant class of polyphenols in white varieties. Total phenolic content is higher in purple varieties due almost entirely to anthocyanin density in purple grape skin compared to absence of anthocyanins in white grape skin. Phenolic content of grape skin varies with cultivar, soil composition, climate, geographic origin, and cultivation practices or exposure to diseases, such as fungal infections.


title: Grape

text: Muscadine grapes contain a relatively high phenolic content among dark grapes. In muscadine skins, ellagic acid, myricetin, quercetin, kaempferol, and trans-resveratrol are major phenolics.


title: Grape

text: The flavonols syringetin, syringetin 3-O-galactoside, laricitrin and laricitrin 3-O-galactoside are also found in purple grape but absent in white grape.


title: Grape

text: Muscadine grape seeds contain about twice the total polyphenol content of skins. Grape seed oil from crushed seeds is used in cosmeceuticals and skincare products. Grape seed oil, including tocopherols (vitamin E) and high contents of phytosterols and polyunsaturated fatty acids such as linoleic acid, oleic acid, and alpha-linolenic acid.


title: Grape

text: Resveratrol, a stilbene compound, is found in widely varying amounts among grape varieties, primarily in their skins and seeds. Muscadine grapes have about one hundred times higher concentration of stilbenes than pulp. Fresh grape skin contains about 50 to 100 micrograms of resveratrol per gram.


title: Grape

text: Comparing diets among Western countries, researchers have discovered that although French people tend to eat higher levels of animal fat, the incidence of heart disease remains low in France. This phenomenon has been termed the French paradox, and is thought to occur from protective benefits of regularly consuming red wine, among other dietary practices. Alcohol consumption in moderation may be cardioprotective by its minor anticoagulant effect and vasodilation.


title: Grape

text: Although adoption of wine consumption is generally not recommended by health authorities, some research indicates moderate consumption, such as one glass of red wine a day for women and two for men, may confer health benefits. Alcohol itself may have protective effects on the cardiovascular system.


title: Grape

text: The consumption of grapes and raisins presents a potential health threat to dogs. Their toxicity to dogs can cause the animal to develop acute kidney failure (the sudden development of kidney failure) with anuria (a lack of urine production) and may be fatal.


title: Grape

text: Christians have traditionally used wine during worship services as a means of remembering the blood of Jesus Christ which was shed for the remission of sins. Christians who oppose the partaking of alcoholic beverages sometimes use grape juice as the "cup" or "wine" in the Lord's Supper.


title: Grape

text: The Catholic Church continues to use wine in the celebration of the Eucharist because it is part of the tradition passed down through the ages starting with Jesus Christ at the Last Supper, where Catholics believe the consecrated bread and wine become the body and blood of Jesus Christ, a dogma known as transubstantiation. Wine is used (not grape juice) both due to its strong Scriptural roots, and also to follow the tradition set by the early Christian Church. The Code of Canon Law of the Catholic Church (1983), Canon 924 says that the wine used must be natural, made from grapes of the vine, and not corrupt.


title: Assault rifle

text: An assault rifle is a selective fire rifle that uses an intermediate cartridge and a detachable magazine. Assault rifles were first put into mass production and accepted into widespread service during World War II. The first assault rifle to see major usage was the German StG 44, a development of the earlier Mkb 42. While immediately after World War II, NATO countries were equipped with battle rifles, the development of the M16 rifle during the Vietnam War prompted the adoption of assault rifles by the rest of NATO. By the end of the 20th century, assault rifles had become the standard weapon in most of the world's armies, replacing full-powered rifles and sub-machine guns in most roles. The two most successful modern assault rifles are the AK-47 and the M16 designs and their derivatives.


title: Assault rifle

text: The term "assault rifle" is generally attributed to Adolf Hitler, who used the German word "Sturmgewehr" (which translates to "assault rifle") as the new name for the MP 43 ("Maschinenpistole)", subsequently known as the Sturmgewehr 44. Allied propaganda suggested that the name was chosen for propaganda purposes, but the main purpose was to differentiate the Sturmgewehr from German submachine guns such as the MP 40.


title: Assault rifle

text: It has been suggested, however, that the "Heereswaffenamt" was responsible for the name "Sturmgewehr", and Hitler had no input besides signing the production order. Furthermore, Hitler was initially opposed to the idea of a new infantry rifle, as Germany lacked the industrial capacity to replace the 12,000,000 Karabiner 98k rifles already in service, only changing his mind once he saw it first-hand.


title: Assault rifle

text: The StG 44 is generally considered the first selective fire military rifle to popularize the assault rifle concept. Today, the term "assault rifle" is used to define firearms sharing the same basic characteristics as the StG 44.


title: Assault rifle

text: The U.S. Army defines "assault rifles" as "short, compact, selective-fire weapons that fire a cartridge intermediate in power between submachine gun and rifle cartridges." In this strict definition, a firearm must have at least the following characteristics to be considered an assault rifle:


title: Assault rifle

text: Rifles that meet most of these criteria, but not all, are not "assault rifles" according to the U.S. Army's definition. For example:


title: Assault rifle

text: In the United States, selective-fire rifles are legally defined as "machine guns", and civilian ownership of those has been tightly regulated since 1934 under the National Firearms Act and since 1986 under the Firearm Owners Protection Act. However, the term "assault rifle" is often conflated with "assault weapon", a U.S. legal category with varying definitions which includes many semi-automatic weapons. This use has been described as incorrect and a misapplication of the term.


title: Assault rifle

text: The Germans were the first to pioneer the assault rifle concept during World War II, based upon research that showed that most firefights happen within and that contemporary rifles were overpowered for most small arms combat. They would soon develop a select-fire intermediate powered rifle combining the firepower of a submachine gun with the range and accuracy of a rifle.


title: Assault rifle

text: The result was the Sturmgewehr 44, an improvement of the earlier Maschinenkarabiner 42(H), and approximately half a million Sturmgewehrs were produced by the war's end. It fired a new and revolutionary intermediate powered cartridge, the 7.92×33mm Kurz. This new cartridge was developed by shortening the standard 7.92×57mm Mauser round and giving it a lighter 125-grain bullet, which limited range but allowed for more controllable automatic fire. A smaller, lighter cartridge also allowed soldiers to carry more ammunition "to support the higher consumption rate of automatic fire."


title: Assault rifle

text: The Sturmgewehr 44 features an inexpensive, easy-to-make, stamped steel design and a 30-round detachable box magazine. "This weapon was the prototype of all successful automatic rifles. Characteristically (and unlike previous rifles) it had a straight stock with the barrel under the gas cylinder to reduce the turning moment of recoil of the rifle in the shoulder and thus help reduce the tendency of shots to climb in automatic fire. The barrel and overall length were shorter than a traditional rifle and it had a pistol grip to hold the weapon more securely in automatic fire. "The principle of this weapon—the reduction of muzzle impulse to get usable automatic fire within the actual ranges of combat—was probably the most important advance in small arms since the invention of smokeless powder."


title: Assault rifle

text: Like the Germans, the Soviets were influenced by experience showing that most combat engagements occur within and that their soldiers were consistently outgunned by heavily armed German troops, especially those armed with Sturmgewehr 44 assault rifles. On July 15, 1943, a Sturmgewehr was demonstrated before the People's Commissariat of Arms of the USSR. The Soviets were so impressed with the Sturmgewehr, that they immediately set about developing an intermediate caliber automatic rifle of their own, to replace the badly outdated Mosin–Nagant bolt-action rifles and PPSh-41 submachine guns that armed most of the Red Army.


title: Assault rifle

text: The Soviets soon developed the 7.62×39mm M43 cartridge, which was first used in the semi-automatic SKS carbine and the RPD light machine gun. Hugo Schmeisser, the designer of the Sturmgewehr, was captured after World War II, and helped develop the AK-47 assault rifle, which would quickly replace the SKS and Mosin in Soviet service. The AK-47 was finalized, adopted and entered widespread service in the Soviet army in the early 1950s. Its firepower, ease of use, low production costs, and reliability were perfectly suited for the Red Army's new mobile warfare doctrines. In the 1960s, the Soviets introduced the RPK light machine gun, itself an AK-47 type weapon with a bipod, a stronger receiver, and a longer, heavier barrel that would eventually replace the RPD light machine gun. The AK-47 has been continually worked upon, and improved. The AKM, AK-74, and AK-12 were all designed by Mikhail Kalashnikov, and have all been service rifles in the Soviet Union, and the later Russian Federation.


title: Assault rifle

text: The AK-47 was widely supplied or sold to nations allied with the USSR, and the blueprints were shared with several friendly nations (the People's Republic of China standing out among these with the Type 56). As a result, more AK-type weapons have been produced than all other assault rifles combined. As of 2004, "of the estimated 500 million firearms worldwide, approximately 100 million belong to the Kalashnikov family, three-quarters of which are AK-47s."


title: Assault rifle

text: The U.S. Army was influenced by combat experience with semi-automatic weapons such as the M1 Garand and M1 Carbine, which enjoyed a significant advantage over enemies armed primarily with bolt-action rifles. Although U.S. Army studies of World War II combat accounts had very similar results to that of the Germans and Soviets, the U.S. Army failed to recognize the importance of the assault rifle concept, and instead maintained its traditional views and preference for high-powered semi-automatic rifles. At the time, the U.S. Army believed that the Sturmgewehr 44 was "intended in a general way to serve the same purpose as the U.S. carbine" and was in many ways inferior to the M1 carbine, and was of "little importance".


title: Assault rifle

text: After World War II, the United States military started looking for a single automatic rifle to replace the M1 Garand, M1/M2 Carbines, M1918 Browning Automatic Rifle, M3 "Grease Gun" and Thompson submachine gun. Early experiments with select-fire versions of the M1 Garand proved disappointing. During the Korean War, the select-fire M2 Carbine largely replaced the submachine gun in U.S. service and became the most widely used Carbine variant. Combat experience suggested that the .30 Carbine round was under-powered. American weapons designers reached the same conclusion as the German and Soviet ones: an intermediate round was necessary, and recommended a small-caliber, high-velocity cartridge.


title: Assault rifle

text: Senior American commanders had faced fanatical enemies and experienced major logistical problems during World War II and the Korean War, and insisted that a single powerful .30 caliber cartridge be developed, that could be used by the new automatic rifle, and also by the new general-purpose machine gun (GPMG) in concurrent development. This culminated in the development of the 7.62×51mm NATO cartridge and the M14 rifle which was basically an improved select-fire M1 Garand with a 20-round magazine. The U.S. also adopted the M60 GPMG, which replaced the M1919 Browning machine gun in major combat roles. Its NATO partners adopted the FN FAL and Heckler & Koch G3 rifles, as well as the FN MAG and Rheinmetall MG3 GPMGs.


title: Assault rifle

text: The FN FAL is a 7.62×51mm, selective fire, automatic rifle produced by the Belgian armaments manufacturer Fabrique Nationale de Herstal (FN). During the Cold War it was adopted by many North Atlantic Treaty Organization (NATO) countries, most notably with the British Commonwealth as the semi-automatic L1A1. It is one of the most widely used rifles in history, having been used by more than 90 countries. The FAL was predominantly chambered for the 7.62mm NATO round, and because of its prevalence and widespread use among the armed forces of many western nations during the Cold War, it was nicknamed "The right arm of the Free World".


title: Assault rifle

text: The Heckler & Koch G3 is a 7.62×51mm, selective fire, automatic rifle produced by the German armament manufacturer Heckler & Koch GmbH (H&K) in collaboration with the Spanish state-owned design and development agency CETME ("Centro de Estudios Técnicos de Materiales Especiales"). The rifle proved successful in the export market, being adopted by the armed forces of over 60 countries. After World War II, German technicians involved in developing the Sturmgewehr 45, continued their research in France at CEAM. The StG 45 mechanism was modified by Ludwig Vorgrimler and Theodor Löffler at the Mulhouse facility between 1946 and 1949. Vorgrimler later went to work at CETME in Spain and developed the line of CETME automatic rifles based on his improved StG 45 design. Germany eventually purchased the license for the CETME design and manufactured the Heckler & Koch G3 as well as an entire line of weapons built on the same system, one of the most famous being the MP5 SMG.


title: Assault rifle

text: The first confrontations between the AK-47 and the M14 ("assault rifle" vs "battle rifle") came in the early part of the Vietnam War. Battlefield reports indicated that the M14 was uncontrollable in full-auto and that soldiers could not carry enough ammunition to maintain fire superiority over the AK-47. And, while the M2 Carbine offered a high rate of fire, it was under-powered and ultimately outclassed by the AK-47. A replacement was needed: A medium between the traditional preference for high-powered rifles such as the M14, and the lightweight firepower of the M2 Carbine.


title: Assault rifle

text: As a result, the Army was forced to reconsider a 1957 request by General Willard G. Wyman, commander of the U.S. Continental Army Command (CONARC) to develop a .223 caliber (5.56 mm) select-fire rifle weighing when loaded with a 20-round magazine. The 5.56 mm round had to penetrate a standard U.S. helmet at and retain a velocity in excess of the speed of sound, while matching or exceeding the wounding ability of the .30 Carbine cartridge.


title: Assault rifle

text: This request ultimately resulted in the development of a scaled-down version of the ArmaLite AR-10, called the ArmaLite AR-15 rifle. However, despite overwhelming evidence that the AR-15 could bring more firepower to bear than the M14, the Army opposed the adoption of the new rifle. In January 1963, Secretary of Defense Robert McNamara concluded that the AR-15 was the superior weapon system and ordered a halt to M14 production. At the time, the AR-15 was the only rifle available that could fulfill the requirement of a universal infantry weapon for issue to all services.


title: Assault rifle

text: After modifications (most notably, the charging handle was re-located from under the carrying handle like it was on AR-10 to the rear of the receiver), the newly redesigned rifle was subsequently adopted as the M16 Rifle. "(The M16) was much lighter compared to the M14 it replaced, ultimately allowing soldiers to carry more ammunition. The air-cooled, gas-operated, magazine-fed assault rifle was made of steel, aluminum alloy and composite plastics, truly cutting-edge for the time. Designed with full and semi-automatic capabilities, the weapon initially did not respond well to wet and dirty conditions, sometimes even jamming in combat. After a few minor modifications, the weapon gained in popularity among troops on the battlefield."


title: Assault rifle

text: Despite its early failures, the M16 proved to be a revolutionary design and stands as the longest continuously serving rifle in American military history. It has been adopted by many U.S. allies and the 5.56×45mm NATO cartridge has become not only the NATO standard but "the standard assault-rifle cartridge in much of the world." It also led to the development of small-caliber high-velocity service rifles by every major army in the world, including the USSR and People's Republic of China. Today, many small arms experts consider the M16 the standard by which all other assault rifles are judged.


title: Assault rifle

text: During the 1960s other countries would follow the Americans' lead and begin to develop 5.56×45mm assault rifles, most notably Germany with the Heckler & Koch HK33. The HK33 was essentially a smaller 5.56mm version of the 7.62×51mm Heckler & Koch G3 rifle. As one of the first 5.56mm assault rifles on the market, it would go on to become one of the most widely distributed assault rifles. The HK33 featured a modular design with a wide range of accessories (telescoping butt-stocks, optics, bi-pods, etc.) that could be easily removed and arranged in a variety of configurations.


title: Assault rifle

text: The adoption of the M16, the H&K33, and the 5.56×45mm cartridge inspired an international trend towards relatively small-sized, lightweight, high-velocity military service cartridges that allow a soldier to carry more ammunition for the same weight compared to the larger and heavier 7.62×51mm NATO cartridge. The 5.56mm cartridge is also much easier to shoot. In 1961 marksmanship testing, the U.S. Army found that 43% of AR-15 shooters achieved Expert, while only 22% of M-14 rifle shooters did so. Also, a lower recoil impulse, allows for more controllable automatic weapons fire.


title: Assault rifle

text: In March 1970, the U.S. recommended that all NATO forces adopt the 5.56×45mm cartridge. This shift represented a change in the philosophy of the military's long-held position about caliber size. By the middle of the 1970s, other armies were looking at assault rifle-type weapons. A NATO standardization effort soon started and tests of various rounds were carried out starting in 1977. The U.S. offered the 5.56×45mm M193 round, but there were concerns about its penetration in the face of the wider introduction of body armor. In the end the Belgian 5.56×45mm SS109 round was chosen (STANAG 4172) in October 1980. The SS109 round was based on the U.S. cartridge but included a new stronger, heavier, 62-grain bullet design, with better long-range performance and improved penetration (specifically, to consistently penetrate the side of a steel helmet at ).


title: Assault rifle

text: Also during the 1970s, Finland, Israel, South Africa and Sweden introduced AK type assault rifles in 5.56×45mm. During the 1990s, Russia developed the AK-101 in 5.56×45mm NATO for the world export market. In addition, Bulgaria, Czechoslovakia, Hungary, Poland and Yugoslavia (i.e., Serbia) have also rechambered their locally produced assault rifles to 5.56mm NATO.


title: Assault rifle

text: The AK-74 assault rifle was a Soviet answer to the U.S. M16. The Soviet military realized that the M16 had better range and accuracy over the AKM, and that its lighter cartridge allowed soldiers to carry more ammunition. Therefore, in 1967, the USSR issued an official requirement to replace the AKM and the 7.62×39mm cartridge. They soon began to develop the AK-74 and the 5.45×39mm cartridge. AK-74 production began in 1974, and it was unveiled in 1977, when it was carried by Soviet parachute troops during the annual Red Square parade. It would soon replace the AKM and become the standard Soviet infantry rifle. In 1979, the AK-74 saw combat for the first time in Afghanistan, where the lethality of the 5.45mm rounds led to the Mujahadeen dubbing them "poison bullets".


title: Assault rifle

text: The adoption of the 5.56mm NATO and the Russian 5.45×39mm cartridges cemented the worldwide trend toward small caliber, high-velocity cartridges.


title: Assault rifle

text: Following the adoption of the M16, carbine variants were also adopted for close quarters operations. The AR-15 family of weapons served through the Vietnam War. However, these compact assault rifles had design issues, as "the barrel length was halved" to which "upset the ballistics", reducing its range and accuracy and leading "to considerable muzzle flash and blast, so that a large flash suppressor had to be fitted". "Nevertheless, as a short-range weapon it is quite adequate and thus, [despite] its caliber, [the Colt Commando] is classed as a submachine gun." Other compact assault rifles, such as the HK53, AKS-74U and the Daewoo K1, have been made and they have also been called submachine guns.


title: Assault rifle

text: In 1977, Austria introduced the 5.56×45mm Steyr AUG bullpup rifle, often cited as the first successful bullpup rifle, finding service with the armed forces of over twenty countries. It was highly advanced for the 1970s, combining in the same weapon the bullpup configuration, a polymer housing, dual vertical grips, an optical sight as standard, and a modular design. Highly reliable, light, and accurate, the Steyr AUG showed clearly the potential of the bullpup layout. In 1978, France introduced the 5.56×45mm FAMAS bullpup rifle. In 1985, the British introduced the 5.56×45mm L85 bullpup rifle. In the late 1990s, Israel introduced the 5.56mm NATO Tavor TAR-21. In 1997, China adopted the QBZ-95 in the new 5.8×42mm cartridge, which they claim is superior to both the 5.56×45mm and the 5.45×39mm. By the turn of the century, the bullpup assault rifle design had achieved worldwide acceptance.


title: Assault rifle

text: The Heckler & Koch G36 is a 5.56×45mm assault rifle, designed in the early 1990s by Heckler & Koch in Germany as a replacement for the heavier G3. It was accepted into service with the "Bundeswehr" in 1997, replacing the G3. The G36 is gas-operated and feeds from a 30-round detachable box magazine or 100-round C-Mag drum magazine. The G36 was made with the extensive use of lightweight, corrosion-resistant synthetic materials in its design; the receiver housing, stock, trigger group (including the fire control selector and firing mechanism parts), magazine well, handguard and carrying handle are all made of a carbon fiber-reinforced polyamide. The receiver has an integrated steel barrel trunnion (with locking recesses) and a nylon 66 steel reinforced receiver. The standard "Bundeswehr" versions of the G36 are equipped with a unique ZF 3×4° dual optical sight that combines a 3× magnified telescopic sight and an unmagnified reflex sight mounted on top of the telescopic sight. Widely distributed, it has been adopted by over 40 countries and prompted other nations to develop similar composite designs, such as the FX-05 Xiuhcoatl.


title: AJ Styles

text: Allen Neal Jones (born June 2, 1977), better known by his ring name AJ Styles (also stylized as A.J. Styles), is an American professional wrestler. He is currently signed to WWE, where he performs on the Raw brand. Regarded as one of the best in-ring performers of all time, he is also known for his time with New Japan Pro-Wrestling (NJPW) from 2014 to 2016.


title: AJ Styles

text: Jones debuted in 1998 and competed for various independent promotions before gaining initial mainstream exposure in World Championship Wrestling (WCW) in 2001. He gained prominence after signing with TNA, having been described as "the cornerstone of the company since [its] inception"; he won the TNA World Heavyweight Championship twice, the NWA World Heavyweight Championship three times, and was the inaugural titleholder of the X Division Championship, which he won six times. He is also the first TNA Triple Crown and Grand Slam champion. Jones simultaneously appeared in Ring of Honor (ROH) from 2002 to 2006, where he became the inaugural ROH Pure Champion, and wrestled in NJPW between 2014 and 2016, where he won the IWGP Heavyweight Championship twice.