The term tribe is used in many different contexts to refer to a category of human social group. The predominant usage of the term is in the discipline of anthropology; the definition is contested, in part due to conflicting theoretical understandings of social and kinship structures, reflecting the problematic application of this concept to diverse human societies. The concept is contrasted by anthropologists with other social and kinship groups, being hierarchically larger than a lineage or clan, but smaller than a chiefdom, nation or state; these terms are disputed. In some cases tribes have legal recognition and some degree of political autonomy from national or federal government, but this legalistic usage of the term may conflict with anthropological definitions; the word tribe first occurred in English in 12th-century Middle English-literature, in reference to the twelve tribes of Israel. The Middle English word is derived from Old French tribu and, in turn, from Latin tribus, in reference to a supposed tripartite division of the original Roman state along ethnic lines, into tribūs known as the Ramnes and Luceres, according to Marcus Terentius Varro, to the Latins and Etruscans respectively.

The Ramnes were named after Romulus, leader of the Latins, Tities after Titus Tatius, leader of the Sabines, Luceres after Lucumo, leader of an Etruscan army that had assisted the Latins. In 242–240 BC, the Tribal Assembly in the Roman Republic included 35 tribes. According to Livy, the three "tribes" were squadrons of cavalry, rather than ethnic divisions; the ultimate etymology of the term "tribe" is uncertain from the Proto-Indo-European roots tri- and bhew. The classicist Gregory Nagy says, citing the linguist Émile Benveniste, that the Umbrian trifu is derived from a combination of *tri- and *bhu-, where the second element is cognate with the Greek root phúō φύω “to bring forth” and the Greek phulē φυλή "clan, people"; the Greek polis was, like the Roman state divided into phylai. In Europe during the late medieval era, the Bible was written in New Latin and instead of tribus the word phyle was used, derived from the Greek phulē. Considerate debate has accompanied efforts to characterize tribes.

In the popular imagination, tribes reflect a primordial social structure from which all subsequent civilizations and states developed. Anthropologist Elman Service presented a system of classification for societies in all human cultures, based on the evolution of social inequality and the role of the state; this system of classification contains four categories: Hunter-gatherer bands that are egalitarian Tribal societies with some limited instances of social rank and prestige Stratified tribal societies led by chieftains Civilizations, with complex social hierarchies and organized, institutional governmentsTribes are therefore considered to be a political unit formed from an organisation of families based on social or ideological solidarity. Membership of a tribe may be understood simplistically as being an identity based on factors such as kinship, language, dwelling place, political group, religious beliefs, oral tradition and/or cultural practices. Archaeologists continue to explore the development of pre-state tribes.

Current research suggests that tribal structures constituted one type of adaptation to situations providing plentiful yet unpredictable resources. Such structures proved flexible enough to coordinate production and distribution of food in times of scarcity, without limiting or constraining people during times of surplus; the term "tribe" was in common use in the field of anthropology until the late 1960s. The continued use of the term has attracted controversy among anthropologists and other academics active in the social sciences, with scholars of anthropological and ethnohistorical research challenging the utility of the concept. In 1970, anthropologist J. Clyde Mitchell wrote: The tribe, a long respected category of analysis in anthropology, has been the object of some scrutiny by anthropologists... Doubts about the utility of the tribe as an analytical category have certainly arisen out of the rapid involvement of peoples in the remotest parts of the globe, in political and sometimes direct social relationship with industrial nations.

The doubts, are based on the definition and meaning which different scholars give to the term'tribe', its adjective'tribal', its abstract form'tribalism'. Despite the membership boundaries for a tribe being conceptually simple, in reality they are vague and subject to change over time. In his 1975 study, The Notion of the Tribe, anthropologist Morton H. Fried provided numerous examples of tribes that encompassed members who spoke different languages and practiced different rituals, or who shared languages and rituals with members of other tribes, he provided examples of tribes in which people followed different political leaders, or followed the same leaders as members of other tribes. He concluded that tribes in general are characterized by fluid boundaries and dynamism, are not parochial. Part of the difficulty with the term is that it seeks to construct and apply a common conceptual framework across diverse cultures and peoples. Different anthropologists studying different peoples therefore draw conflicting conclusions about the nature and practices of tribes.

Writing on the Kurdish peoples, anthropologist Martin van Bruiness


An evaporator is a device in a process used to turn the liquid form of a chemical substance such as water into its gaseous-form/vapor. The liquid is vaporized, into a gas form of the targeted substance in that process. One kind of evaporator is a kind of radiator coil used in a closed compressor driven circulation of a liquid coolant; that is called an air-conditioning system or refrigeration system to allow a compressed cooling chemical, such as R-22 or R-410A, to evaporate/vaporize from liquid to gas within the system while absorbing heat from the enclosed cooled area, for example a refrigerator or rooms indoors, in the process. This works in the closed A/C or refrigeration system with a condenser radiator coil that exchanges the heat from the coolant, such as into the ambient environment. A different kind of evaporator can be used for heating and boiling a product containing a liquid to cause the liquid to evaporate from the product; the appropriate process can be used to remove water or other liquids from liquid based mixtures.

The process of evaporation is used to concentrate liquid foods, such as soup or make concentrated milk called "condensed milk" done by evaporating water from the milk. In the concentration process, the goal of evaporation is to vaporize most of the water from a solution which contains the desired product. An evaporator/evaporative-process can be used for separating liquid chemicals as well as to salvage solvents. In the case of desalination of sea water or in Zero Liquid Discharge plants, the reverse purpose applies. One of the most important applications of evaporation is in the beverage industry. Foods or beverages that need to last for a considerable amount of time or need to have certain consistency, like coffee, go through an evaporation step during processing. In the pharmaceutical industry, the evaporation process is used to eliminate excess moisture, providing an handled product and improving product stability. Preservation of long-term activity or stabilization of enzymes in laboratories are assisted by the evaporation process.

Another example of evaporation is in the recovery of sodium hydroxide in kraft pulping. Cutting down waste-handling cost is another major reason for large companies to use evaporation applications. All producers of waste must dispose of waste using methods compatible with environmental guidelines. By removing moisture through vaporization, industry can reduce the amount of waste product that must be processed. Water can be removed from solutions in ways other than evaporation, including membrane processes, liquid-liquid extractions and precipitation. Evaporation can be distinguished from some other drying methods in that the final product of evaporation is a concentrated liquid, not a solid, it is relatively simple to use and understand since it has been used on a large scale, many techniques are well known. In order to concentrate a product by water removal, an auxiliary phase is used which allows for easy transport of the solvent rather than the solute. Water vapor is used as the auxiliary phase when concentrating non-volatile components, such as proteins and sugars.

Heat is added to the solution, part of the solvent is converted into vapor. Heat is the main tool in evaporation, the process occurs more at high temperature and low pressures. Heat is needed to provide enough energy for the molecules of the solvent to leave the solution and move into the air surrounding the solution; the energy needed can be expressed as an excess thermodynamic potential of the water in the solution. Leading to one of the biggest problems in industrial evaporation, the process requires enough energy to remove the water from the solution and to supply the heat of evaporation; when removing the water, more than 99% of the energy needed goes towards supplying the heat of evaporation. The need to overcome the surface tension of the solution requires energy; the energy requirement of this process is high because a phase transition must be caused. When designing evaporators, engineers must quantify the amount of steam needed for every mass unit of water removed when a concentration is given.

An energy balance must be used based on an assumption that a negligible amount of heat is lost to the system's surroundings. The heat that needs to be supplied by the condensing steam will equal the heat needed to vaporize the water. Another consideration is the size of the heat exchanger; some common terms for understanding heat transfer: A = heat transfer area, q = overall heat transfer rate, U = overall heat transfer coefficient. The solution containing the desired product is fed into the evaporator and passes across a heat source; the applied heat converts the water in the solution into vapor. The vapor is removed from the rest of the solution and is condensed while the now-concentrated solution is either fed into a second evaporator or is removed; the evaporator, as a machine consists of four sections. The heating section contains the heating medium. Steam is fed into this section; the most common medium consists of parallel tubes but others have plates or coils made from copper or aluminium.

The concentrating and separating section removes the vapor being produced from the solution. The condenser condenses the separated vapor the vacuum or pump provides pressure to increase circulation. Natural circulation evaporators are based on the natural circulation of the product caused by the density differences that arise from heating. In an evapora

Edvin Adolphson

Gustav Edvin Adolphson was a Swedish film actor and director who appeared in over 500 roles. He made his debut in 1912, he appeared with Ingrid Bergman in Only One Night, is noted for his roles in the film Änglar, finns dom?, the television version of August Strindberg's Hemsöborna, as Markurell in Markurells i Wadköping. He directed the first Swedish sound film, Säg det i toner in 1929, he was actress Harriet Bosse's third husband and is father of actress Kristina Adolphson and songwriter/composer Olle Adolphson. Adolphson was born in Furingstad and died in Solna, a suburb of Stockholm, Sweden; the Triumph of the Heart Säg det i toner Love and Deficit Munkbrogreven Russian Flu Dollar Only One Night Ett brott Med dej i mina armar Fröken Kyrkråtta Life Goes On Flames in the Dark Sjätte skottet En dag skall gry Kungliga patrasket Flottans kavaljerer One Summer of Happiness The Nuthouse The Phantom Carriage Änglar, finns dom? Swedish Wedding Night Edvin Adolphson on IMDb Edvin Adolphson at Find a Grave