The Iraq War was a protracted armed conflict that began in 2003 with the invasion of Iraq by a United States-led coalition that overthrew the government of Saddam Hussein. The conflict continued for much of the next decade as an insurgency emerged to oppose the occupying forces and the post-invasion Iraqi government. An estimated 151,000 to 600,000 or more Iraqis were killed in the first three to four years of conflict. In 2009, official US troops were withdrawn, but American soldiers continued to remain on the ground fighting in Iraq, hired by defence contractors and private military companies; the U. S. became re-involved in 2014 at the head of a new coalition. The invasion occurred as part of a declared war against international terrorism and its sponsors under the administration of U. S. President George W. Bush following the unrelated September 11 terrorist attacks. In October 2002, President Bush obtained congressional approval from a Democrat-led Senate and Republican-led House authorizing war-making powers.
The Iraq war began on 19 March 2003, when the U. S. joined by the U. K. and several coalition allies, launched a "awe" bombing campaign. Iraqi forces were overwhelmed as U. S. forces swept through the country. The invasion led to the collapse of the Ba'athist government. However, the power vacuum following Saddam's demise and the mismanagement of the occupation led to widespread sectarian violence between Shias and Sunnis, as well as a lengthy insurgency against U. S. and coalition forces. Many violent insurgent groups were supported by al-Qaeda in Iraq; the United States responded with a troop surge in 2007, a build up of 170,000 troops. The surge in troops gave greater security to Iraq’s government and military, was a success; the winding down of U. S. involvement in Iraq accelerated under President Barack Obama. The U. S. formally withdrew all combat troops from Iraq by December 2011. However, with no stay-behind agreement or advisers left in Iraq, a new power vacuum was created and led to the rise of ISIS.
Nine months after President Trump was elected, U. S.-backed forces captured Raqqa. The Bush administration based its rationale for the war principally on the assertion that Iraq, viewed by the U. S. as a rogue state since the 1990–1991 Gulf War, possessed weapons of mass destruction and that there was concern about an active WMD program, that the Iraqi government posed a threat to the United States and its coalition allies. Select U. S. officials accused Saddam of harbouring and supporting al-Qaeda, while others cited the desire to end a repressive dictatorship and bring democracy to the people of Iraq. Hundreds of chemical weapons were found in Iraq, which were determined to be produced before the 1991 Gulf War, intelligence officials determined they were "so old they couldn't be used as designed." From 2004 to 2011, US troops and American-trained Iraqi troops encountered, on six reported occasions were wounded by, chemical weapons from years earlier in Saddam Hussein's rule. 5,000 chemical warheads, shells or aviation bombs were discovered.
The rationale of U. S. pre-war intelligence faced heavy criticism both domestically and internationally. From 2009 to 2011, the UK conducted a broad inquiry into its decision to go to war chaired by Sir John Chilcot; the Chilcot Report, published in 2016, concluded military action may have been necessary but was not the last resort at the time and that the consequences of invasion were underestimated. In the aftermath of the invasion, Iraq held multi-party elections in 2005. Nouri al-Maliki became Prime Minister in 2006 and remained in office until 2014; the al-Maliki government enacted policies that were seen as having the effect of alienating the country's Sunni minority and worsening sectarian tensions. In the summer of 2014, the Islamic State of Iraq and the Levant launched a military offensive in Northern Iraq and declared a worldwide Islamic caliphate, eliciting another military response from the United States and its allies; the Iraq War caused over a hundred thousand civilian deaths and tens of thousands of military deaths.
The majority of deaths occurred as a result of the insurgency and civil conflicts between 2004 and 2007. Strong international opposition to the Saddam Hussein regime began after Iraq's invasion of Kuwait in 1990; the international community condemned the invasion, in 1991 a military coalition led by the United States launched the Gulf War to expel Iraq from Kuwait. Following the Gulf War, the US and its allies tried to keep Saddam in check with a policy of containment; this policy involved numerous economic sanctions by the UN Security Council. The inspections were carried out by the United Nations Special Commission. UNSCOM, in cooperation with the International Atomic Energy Agency, worked to ensure that Iraq destroyed its chemical and nuclear weapons and facilities. In the decade following the Gulf War, the United Nations passed 16 Security Council resolutions calling for the complete elimination of Iraqi weapons of mass destruction. Member states communicated their frustration over the years that Iraq was impeding the work of the special commission and failing to take its disarmament obligations.
Iraqi officials harass
Jazz is a music genre that originated in the African-American communities of New Orleans, United States, in the late 19th and early 20th centuries, developed from roots in blues and ragtime. Jazz is seen by many as "America's classical music". Since the 1920s Jazz Age, jazz has become recognized as a major form of musical expression, it emerged in the form of independent traditional and popular musical styles, all linked by the common bonds of African-American and European-American musical parentage with a performance orientation. Jazz is characterized by swing and blue notes and response vocals and improvisation. Jazz has roots in West African cultural and musical expression, in African-American music traditions including blues and ragtime, as well as European military band music. Intellectuals around the world have hailed jazz as "one of America's original art forms"; as jazz spread around the world, it drew on national and local musical cultures, which gave rise to different styles. New Orleans jazz began in the early 1910s, combining earlier brass-band marches, French quadrilles, biguine and blues with collective polyphonic improvisation.
In the 1930s arranged dance-oriented swing big bands, Kansas City jazz, a hard-swinging, improvisational style and Gypsy jazz were the prominent styles. Bebop emerged in the 1940s, shifting jazz from danceable popular music toward a more challenging "musician's music", played at faster tempos and used more chord-based improvisation. Cool jazz developed near the end of the 1940s, introducing calmer, smoother sounds and long, linear melodic lines; the 1950s saw the emergence of free jazz, which explored playing without regular meter and formal structures, in the mid-1950s, hard bop emerged, which introduced influences from rhythm and blues and blues in the saxophone and piano playing. Modal jazz developed in the late 1950s, using the mode, or musical scale, as the basis of musical structure and improvisation. Jazz-rock fusion appeared in the late 1960s and early 1970s, combining jazz improvisation with rock music's rhythms, electric instruments, amplified stage sound. In the early 1980s, a commercial form of jazz fusion called smooth jazz became successful, garnering significant radio airplay.
Other styles and genres abound in the 2000s, such as Afro-Cuban jazz. The origin of the word "jazz" has resulted in considerable research, its history is well documented, it is believed to be related to "jasm", a slang term dating back to 1860 meaning "pep, energy". The earliest written record of the word is in a 1912 article in the Los Angeles Times in which a minor league baseball pitcher described a pitch which he called a "jazz ball" "because it wobbles and you can't do anything with it"; the use of the word in a musical context was documented as early as 1915 in the Chicago Daily Tribune. Its first documented use in a musical context in New Orleans was in a November 14, 1916 Times-Picayune article about "jas bands". In an interview with NPR, musician Eubie Blake offered his recollections of the slang connotations of the term, saying, "When Broadway picked it up, they called it'J-A-Z-Z', it wasn't called that. It was spelled'J-A-S-S'; that was dirty, if you knew what it was, you wouldn't say it in front of ladies."
The American Dialect Society named it the Word of the Twentieth Century. Jazz is difficult to define because it encompasses a wide range of music spanning a period of over 100 years, from ragtime to the rock-infused fusion. Attempts have been made to define jazz from the perspective of other musical traditions, such as European music history or African music, but critic Joachim-Ernst Berendt argues that its terms of reference and its definition should be broader, defining jazz as a "form of art music which originated in the United States through the confrontation of the Negro with European music" and arguing that it differs from European music in that jazz has a "special relationship to time defined as'swing'". Jazz involves "a spontaneity and vitality of musical production in which improvisation plays a role" and contains a "sonority and manner of phrasing which mirror the individuality of the performing jazz musician". In the opinion of Robert Christgau, "most of us would say that inventing meaning while letting loose is the essence and promise of jazz".
A broader definition that encompasses different eras of jazz has been proposed by Travis Jackson: "it is music that includes qualities such as swing, group interaction, developing an'individual voice', being open to different musical possibilities". Krin Gibbard argued that "jazz is a construct" which designates "a number of musics with enough in common to be understood as part of a coherent tradition". In contrast to commentators who have argued for excluding types of jazz, musicians are sometimes reluctant to define the music they play. Duke Ellington, one of jazz's most famous figures, said, "It's all music." Although jazz is considered difficult to define, in part because it contains many subgenres, improvisation is one of its defining elements. The centrality of improvisation is attributed to the influence of earlier forms of music such as blues, a form of folk music which arose in part from the work songs and field hollers of African-American slaves on plantations; these work songs were structured around a repetitive call-and-response pattern, but early blues was improvisational.
Classical music performance is evaluated more by its fidelity to the musical score, with less attention given to interpretation and accompaniment. The classical performer's goal is to play the composition. In contrast, jazz is characterized by the product of i
Television, sometimes shortened to tele or telly, is a telecommunication medium used for transmitting moving images in monochrome, or in color, in two or three dimensions and sound. The term can refer to a television set, a television program, or the medium of television transmission. Television is a mass medium for advertising and news. Television became available in crude experimental forms in the late 1920s, but it would still be several years before the new technology would be marketed to consumers. After World War II, an improved form of black-and-white TV broadcasting became popular in the United States and Britain, television sets became commonplace in homes and institutions. During the 1950s, television was the primary medium for influencing public opinion. In the mid-1960s, color broadcasting was introduced in most other developed countries; the availability of multiple types of archival storage media such as Betamax, VHS tape, local disks, DVDs, flash drives, high-definition Blu-ray Discs, cloud digital video recorders has enabled viewers to watch pre-recorded material—such as movies—at home on their own time schedule.
For many reasons the convenience of remote retrieval, the storage of television and video programming now occurs on the cloud. At the end of the first decade of the 2000s, digital television transmissions increased in popularity. Another development was the move from standard-definition television to high-definition television, which provides a resolution, higher. HDTV may be transmitted in various formats: 1080p, 720p. Since 2010, with the invention of smart television, Internet television has increased the availability of television programs and movies via the Internet through streaming video services such as Netflix, Amazon Video, iPlayer and Hulu. In 2013, 79 % of the world's households owned; the replacement of early bulky, high-voltage cathode ray tube screen displays with compact, energy-efficient, flat-panel alternative technologies such as LCDs, OLED displays, plasma displays was a hardware revolution that began with computer monitors in the late 1990s. Most TV sets sold in the 2000s were flat-panel LEDs.
Major manufacturers announced the discontinuation of CRT, DLP, fluorescent-backlit LCDs by the mid-2010s. In the near future, LEDs are expected to be replaced by OLEDs. Major manufacturers have announced that they will produce smart TVs in the mid-2010s. Smart TVs with integrated Internet and Web 2.0 functions became the dominant form of television by the late 2010s. Television signals were distributed only as terrestrial television using high-powered radio-frequency transmitters to broadcast the signal to individual television receivers. Alternatively television signals are distributed by coaxial cable or optical fiber, satellite systems and, since the 2000s via the Internet; until the early 2000s, these were transmitted as analog signals, but a transition to digital television is expected to be completed worldwide by the late 2010s. A standard television set is composed of multiple internal electronic circuits, including a tuner for receiving and decoding broadcast signals. A visual display device which lacks a tuner is called a video monitor rather than a television.
The word television comes from Ancient Greek τῆλε, meaning'far', Latin visio, meaning'sight'. The first documented usage of the term dates back to 1900, when the Russian scientist Constantin Perskyi used it in a paper that he presented in French at the 1st International Congress of Electricity, which ran from 18 to 25 August 1900 during the International World Fair in Paris; the Anglicised version of the term is first attested in 1907, when it was still "...a theoretical system to transmit moving images over telegraph or telephone wires". It was "...formed in English or borrowed from French télévision." In the 19th century and early 20th century, other "...proposals for the name of a then-hypothetical technology for sending pictures over distance were telephote and televista." The abbreviation "TV" is from 1948. The use of the term to mean "a television set" dates from 1941; the use of the term to mean "television as a medium" dates from 1927. The slang term "telly" is more common in the UK; the slang term "the tube" or the "boob tube" derives from the bulky cathode ray tube used on most TVs until the advent of flat-screen TVs.
Another slang term for the TV is "idiot box". In the 1940s and throughout the 1950s, during the early rapid growth of television programming and television-set ownership in the United States, another slang term became used in that period and continues to be used today to distinguish productions created for broadcast on television from films developed for presentation in movie theaters; the "small screen", as both a compound adjective and noun, became specific references to television, while the "big screen" was used to identify productions made for theatrical release. Facsimile transmission systems for still photographs pioneered methods of mechanical scanning of images in the early 19th century. Alexander Bain introduced the facsimile machine between 1843 and 1846. Frederick Bakewell demonstrated a working laboratory version in 1851. Willoughby Smith discovered the photoconductivity of the element selenium in 1873; as a 23-year-old German university student, Paul Julius Gottlieb Nipkow proposed and patented the Nipkow disk in 1884.
This was a spinning disk with a spiral pattern of holes in it, so each hole scanned a line of the image. Although he never built a working model
BBC News is an operational business division of the British Broadcasting Corporation responsible for the gathering and broadcasting of news and current affairs. The department is the world's largest broadcast news organisation and generates about 120 hours of radio and television output each day, as well as online news coverage; the service maintains 50 foreign news bureaus with more than 250 correspondents around the world. Fran Unsworth has been Director of News and Current Affairs since January 2018; the department's annual budget is in excess of £350 million. BBC News' domestic and online news divisions are housed within the largest live newsroom in Europe, in Broadcasting House in central London. Parliamentary coverage is broadcast from studios in Millbank in London. Through the BBC English Regions, the BBC has regional centres across England, as well as national news centres in Northern Ireland and Wales. All nations and English regions produce their own local news programmes and other current affairs and sport programmes.
The BBC is a quasi-autonomous corporation authorised by Royal Charter, making it operationally independent of the government, who have no power to appoint or dismiss its director-general, required to report impartially. As with all major media outlets it has been accused of political bias from across the political spectrum, both within the UK and abroad; the British Broadcasting Company broadcast its first radio bulletin from radio station.2LO In 14 November 1922. Wishing to avoid competition, newspaper publishers persuaded the government to ban the BBC from broadcasting news before 7:00 pm, to force it to use wire service copy instead of reporting on its own. On Easter weekend in 1930, this reliance on newspaper wire services left the radio news service with no information to report after saying There is no news today. Piano music was played instead; the BBC gained the right to edit the copy and, in 1934, created its own news operation. However, it could not broadcast news before 6 PM until World War II.
Gaumont British and Movietone cinema newsreels had been broadcast on the TV service since 1936, with the BBC producing its own equivalent Television Newsreel programme from January 1948. A weekly Children's Newsreel was inaugurated on 23 April 1950, to around 350,000 receivers; the network began simulcasting its radio news on television in 1946, with a still picture of Big Ben. Televised bulletins began on 5 July 1954, broadcast from leased studios within Alexandra Palace in London; the public's interest in television and live events was stimulated by Elizabeth II's coronation in 1953. It is estimated that up to 27 million people viewed the programme in the UK, overtaking radio's audience of 12 million for the first time; those live pictures were fed from 21 cameras in central London to Alexandra Palace for transmission, on to other UK transmitters opened in time for the event. That year, there were around two million TV Licences held in the UK, rising to over three million the following year, four and a half million by 1955.
Television news, although physically separate from its radio counterpart, was still under radio news' control – correspondents provided reports for both outlets–and that first bulletin, shown on 5 July 1954 on the BBC television service and presented by Richard Baker, involved his providing narration off-screen while stills were shown. This was followed by the customary Television Newsreel with a recorded commentary by John Snagge, it was revealed that this had been due to producers fearing a newsreader with visible facial movements would distract the viewer from the story. On-screen newsreaders were introduced a year in 1955 – Kenneth Kendall, Robert Dougall, Richard Baker–three weeks before ITN's launch on 21 September 1955. Mainstream television production had started to move out of Alexandra Palace in 1950 to larger premises – at Lime Grove Studios in Shepherd's Bush, west London – taking Current Affairs with it, it was from here that the first Panorama, a new documentary programme, was transmitted on 11 November 1953, with Richard Dimbleby becoming anchor in 1955.
On 18 February 1957, the topical early-evening programme Tonight, hosted by Cliff Michelmore and designed to fill the airtime provided by the abolition of the Toddlers' Truce, was broadcast from Marconi's Viking Studio in St Mary Abbott's Place, Kensington – with the programme moving into a Lime Grove studio in 1960, where it maintained its production office. On 28 October 1957, the Today programme, a morning radio programme, was launched in central London on the Home Service. In 1958, Hugh Carleton Greene became head of Current Affairs, he set up a BBC study group whose findings, published in 1959, were critical of what the television news operation had become under his predecessor, Tahu Hole. The report proposed that the head of television news should take control, that the television service should have a proper newsroom of its own, with an editor-of-the-day. On 1 January 1960, Greene became Director-General and brought about big changes at BBC Television and BBC Television News. BBC Television News had been created in 1955, in response to the founding of ITN.
The changes made by Greene were aimed at making BBC reporting more similar to ITN, rated by study groups held by Greene. A newsroom was created at Alexandra Palace, television reporters were recruited and given the opportunity to write and voice their own scripts–without the "impossible burden" of having to cover stories for radio too. In 1987 thirty years John B
Los Angeles the City of Los Angeles and known by its initials L. A. is the most populous city in California, the second most populous city in the United States, after New York City, the third most populous city in North America. With an estimated population of four million, Los Angeles is the cultural and commercial center of Southern California; the city is known for its Mediterranean climate, ethnic diversity and the entertainment industry, its sprawling metropolis. Los Angeles is the largest city on the West Coast of North America. Los Angeles is in a large basin bounded by the Pacific Ocean on one side and by mountains as high as 10,000 feet on the other; the city proper, which covers about 469 square miles, is the seat of Los Angeles County, the most populated county in the country. Los Angeles is the principal city of the Los Angeles metropolitan area, the second largest in the United States after that of New York City, with a population of 13.1 million. It is part of the Los Angeles-Long Beach combined statistical area the nation's second most populous area with a 2015 estimated population of 18.7 million.
Los Angeles is one of the most substantial economic engines within the United States, with a diverse economy in a broad range of professional and cultural fields. Los Angeles is famous as the home of Hollywood, a major center of the world entertainment industry. A global city, it has been ranked 6th in the Global Cities Index and 9th in the Global Economic Power Index; the Los Angeles metropolitan area has a gross metropolitan product of $1.044 trillion, making it the third-largest in the world, after the Tokyo and New York metropolitan areas. Los Angeles hosted the 1932 and 1984 Summer Olympics and will host the event for a third time in 2028; the city hosted the Miss Universe pageant twice, in 1990 and 2006, was one of 9 American cities to host the 1994 FIFA men's soccer World Cup and one of 8 to host the 1999 FIFA women's soccer World Cup, hosting the final match for both tournaments. Home to the Chumash and Tongva, Los Angeles was claimed by Juan Rodríguez Cabrillo for Spain in 1542 along with the rest of what would become Alta California.
The city was founded on September 4, 1781, by Spanish governor Felipe de Neve. It became a part of Mexico in 1821 following the Mexican War of Independence. In 1848, at the end of the Mexican–American War, Los Angeles and the rest of California were purchased as part of the Treaty of Guadalupe Hidalgo, becoming part of the United States. Los Angeles was incorporated as a municipality on April 4, 1850, five months before California achieved statehood; the discovery of oil in the 1890s brought rapid growth to the city. The completion of the Los Angeles Aqueduct in 1913, delivering water from Eastern California assured the city's continued rapid growth; the Los Angeles coastal area was settled by the Chumash tribes. A Gabrieleño settlement in the area was called iyáangẚ, meaning "poison oak place". Maritime explorer Juan Rodríguez Cabrillo claimed the area of southern California for the Spanish Empire in 1542 while on an official military exploring expedition moving north along the Pacific coast from earlier colonizing bases of New Spain in Central and South America.
Gaspar de Portolà and Franciscan missionary Juan Crespí, reached the present site of Los Angeles on August 2, 1769. In 1771, Franciscan friar Junípero Serra directed the building of the Mission San Gabriel Arcángel, the first mission in the area. On September 4, 1781, a group of forty-four settlers known as "Los Pobladores" founded the pueblo they called El Pueblo de Nuestra Señora la Reina de los Ángeles,'The Town of Our Lady the Queen of the Angels'; the present-day city has the largest Roman Catholic Archdiocese in the United States. Two-thirds of the Mexican or settlers were mestizo or mulatto, a mixture of African and European ancestry; the settlement remained a small ranch town for decades, but by 1820, the population had increased to about 650 residents. Today, the pueblo is commemorated in the historic district of Los Angeles Pueblo Plaza and Olvera Street, the oldest part of Los Angeles. New Spain achieved its independence from the Spanish Empire in 1821, the pueblo continued as a part of Mexico.
During Mexican rule, Governor Pío Pico made Los Angeles Alta California's regional capital. Mexican rule ended during the Mexican–American War: Americans took control from the Californios after a series of battles, culminating with the signing of the Treaty of Cahuenga on January 13, 1847. Railroads arrived with the completion of the transcontinental Southern Pacific line to Los Angeles in 1876 and the Santa Fe Railroad in 1885. Petroleum was discovered in the city and surrounding area in 1892, by 1923, the discoveries had helped California become the country's largest oil producer, accounting for about one-quarter of the world's petroleum output. By 1900, the population had grown to more than 102,000; the completion of the Los Angeles Aqueduct in 1913, under the supervision of William Mulholland, assured the continued growth of the city. Due to clauses in the city's charter that prevented the City of Los Angeles from selling or providing water from the aqueduct to any area outside its borders, many adjacent city and communities became compelled to annex themselves into Los Angeles.
Los Angeles created the first municipal zoning ordinance in the United States. On September 14, 1908, the Los Angeles City Council promulgated residential and industrial land use zones; the new ordinance established three residential zones of a single type, where industrial uses were
A dressmaker is a person who makes custom clothing for women, such as dresses and evening gowns. A dressmaker is called a mantua-maker or a modiste. Cristóbal Balenciaga Pierre Balmain Coco Chanel Christian Dior David Emanuel Jean Muir, fashion designer Anna and Laura Tirocchi, Rhode Island Isabel Toledo Madeleine Vionnet Charles Frederick Worth Elizabeth Keckley and confidante to Mary Todd Lincoln Janet Walker and dress making bust inventor Dressmaker denotes clothing made in the style of a dressmaker in the term dressmaker details which includes ruffles, ribbon or braid trim. Dressmaker in this sense is contrasted to tailored and has fallen out of use since the rise of casual wear in the mid-twentieth century. Mantua-maker, in the eighteenth century a maker of mantuas, or in general a dressmaker. Modiste, a maker of fashionable clothing and accessories, with the implication that the articles made reflect the current Paris fashions. Sewing professional is the most general term for those who make their living by sewing, writing about sewing, or retailing sewing supplies.
She or he may work out of her home, a studio, or retail shop, may work part-time or full-time. She or he may be any or all or the following sub-specialities: A custom clothier makes custom garments one at a time, to order, to meet an individual customer's needs and preferences. A custom dressmaker specializes in women's custom apparel, including day dresses, suits, evening or bridal wear, sportswear, or lingerie. A tailor makes custom menswear-style jackets and the skirts or trousers that go with them, for men or women. An alterations specialist or alterationist adjusts the fit of completed garments ready-to-wear, or restyles them. Note that while all tailors can do alterations, by no means can all alterationists do tailoring. Designers choose combinations of line, proportion and texture for intended garments, they may have no sewing or patternmaking skills, may only sketch or conceptualize garments. Patternmakers flat draft the shapes and sizes of the numerous pieces of a garment by hand using paper and measuring tools or by computer using CAD software, or by draping muslin on a dressform.
A wardrobe consultant or fashion advisor recommends colors for a client. A seamstress is someone who sews seams, or in other words, a machine operator in a factory who may not have the skills to make garments from scratch or to fit them on a real body; this term is not a synonym for dressmaker. Prior to the Industrial Revolution, a seamstress did handsewing under the putting-out system. Older variants are sempstress. Sewist is a new term, combining the words "sew" and "artist", to describe someone who creates sewn works of art, which can include clothing or other items made with sewn elements. Bespoke Fashion design Haute couture Sewing Tailor Butterick Publishing Company: "The Art of Garment Cutting and Making", 1894. Deckert, Barbara: Sewing for Plus Sizes: Design and Construction for Ample Apparel, Taunton, 1999, Appendix B: How to Find and Work With a Custom Clothier, pp. 142-143. Kirke, Betty: "Madeleine Vionnet", Chronicle Books, 1998. Picken, Mary Brooks: The Fashion Dictionary and Wagnalls, 1957
An automotive battery is a rechargeable battery that supplies electrical current to a motor vehicle. Its main purpose is to feed the starter. Once the engine is running, power for the car's electrical systems is supplied by the alternator. Starting uses less than three percent of the battery capacity. For this reason, automotive batteries are designed to deliver maximum current for a short period of time, they are sometimes referred to as "SLI batteries" for this reason, for Starting and Ignition. SLI batteries are not designed for deep discharging, a full discharge can reduce the battery's lifespan; as well as starting the engine, an SLI battery supplies the extra power necessary when the vehicle's electrical requirements exceed the supply from the charging system. It is a stabilizer, evening out damaging voltage spikes. While the engine is running, most of the power is provided by the alternator, which includes a voltage regulator to keep the output between 13.5 and 14.5 V. Modern SLI batteries are lead-acid type, using six series-connected cells to provide a nominal 12 volt system, or twelve cells for a 24 volt system in heavy trucks or earth-moving equipment, for example.
Battery electric vehicles are powered by a high-voltage electric vehicle battery, but they have an automotive battery as well, so that they can use standard automotive accessories which are designed to run on 12 V. Early cars did not have batteries. A bell was used instead of an electric horn, headlights were gas-powered, the engine was started with a crank. Car batteries became used around 1920 as cars became equipped with electric starters; the sealed battery, which did not require refilling, was invented in 1971. The first starting and charging systems were designed to be 6-volt and positive-ground systems, with the vehicle's chassis directly connected to the positive battery terminal. Today, all road vehicles have a negative ground system; the negative battery terminal is connected to the car's chassis. The Hudson Motor Car Company was the first to use a standardized battery in 1918 when they started using Battery Council International batteries. BCI is the organization. Cars used batteries until the mid-1950s.
The changeover from 6 to 12 V happened when bigger engines with higher compression ratios required more electrical power to start. Smaller cars, which required less power to start stayed with 6 V longer, for example the Volkswagen Beetle in the mid-1960s and the Citroën 2CV in 1970. In the 1990s a 42V electrical system standard was proposed, it was intended to allow more powerful electrically driven accessories, lighter automobile wiring harnesses. The availability of higher-efficiency motors, new wiring techniques, digital controls, a focus on hybrid vehicle systems that use high-voltage starter/generators have eliminated the push for switching the main automotive voltages. An automobile battery is an example of a wet cell battery, with six cells; each cell of a lead storage battery consists of alternate plates made of a lead alloy grid filled with sponge lead (cathode plates} or coated with lead dioxide. Each cell is filled with a sulfuric acid solution, the electrolyte. Cells each had a filler cap, through which the electrolyte level could be viewed and which allowed water to be added to the cell.
The filler cap had a small vent hole which allowed hydrogen gas generated during charging to escape from the cell. The cells are connected by short heavy straps from the positive plates of one cell to the negative plates of the adjacent cell. A pair of heavy terminals, plated with lead to resist corrosion, are mounted at the top, sometimes the side, of the battery. Early auto batteries used hard rubber cases and wooden plate separators. Modern units use plastic cases and woven sheets to prevent the plates of a cell from touching and short-circuiting. In the past, auto batteries required regular inspection and maintenance to replace water, decomposed during operation of the battery. "low maintenance" batteries use a different alloy for the plate elements, reducing the amount of water decomposed on charging. A modern battery may not require additional water over its useful life. A weakness of these batteries is that they are intolerant of deep discharge, for example when the car battery is drained by leaving the lights on.
This coats the lead plate electrodes with sulfate deposits and can reduce the battery's lifespan by a third or more. VRLA batteries known as absorbed glass mat batteries are more tolerant of deep discharge, but are more expensive. VRLA batteries do not permit addition of water to the cell; the cells each have an automatic pressure release valve, to protect the case from rupture on severe overcharge or internal failure. A VRLA battery cannot spill its electrolyte which makes it useful in vehicles such as motorcycles. Batteries are made of six galvanic cells in a series circuit; each cell provides 2.1 volts for a total of 12.6 volts at full charge. During discharge, a chemical reaction releases electrons, allowing them to flow through conductors to produce electricity; as the battery discharges, the acid of the electrolyte reacts with the materials of the plates, changing their surface to lead sulfate. When the battery is recharged, the chemical reaction is reversed: the lead sulfate reforms into lead dioxide.
With the plates restored to their original condition, the process may be repeated. Some vehicles use other starter batteries