Diaphragm (optics)

In optics, a diaphragm is a thin opaque structure with an opening (aperture) at its center. The role of the diaphragm is to stop the passage of light, except for the light passing through the aperture. Thus it is also called a stop (an aperture stop, if it limits the brightness of light reaching the focal plane, or a field stop or flare stop for other uses of diaphragms in lenses). The diaphragm is placed in the light path of a lens or objective, and the size of the aperture regulates the amount of light that passes through the lens. The centre of the diaphragm's aperture coincides with the optical axis of the lens system.

Most modern cameras use a type of adjustable diaphragm known as an iris diaphragm, and often referred to simply as an iris.

See the articles on aperture and f-number for the photographic effect and system of quantification of varying the opening in the diaphragm.

Iris diaphragms versus other types

A natural optical system that has a diaphragm and an aperture is the human eye. The iris is the diaphragm, and the opening in the iris of the eye (the pupil) is the aperture. An analogous dev in a photographic lens is called an iris diaphragm.

Iris (1987 film)

Iris is a 1987 Netherlands film directed by Mady Saks and starring Monique van de Ven.

Plot

A young woman, Iris, runs away to the big city on her eighteenth birthday. She moves in with an architect and decides to become a veterinarian. With an inheritance she buys an existing clinic in a backwoods town where Iris is leered at by the men, scorned by the women. Cruel jokes and gossip eventually lead to violence.A local thug breaks in her house while she is out. When she returns home late night, he attacks her, drag her to the wooden stairs, ties her hands, stretch her legs wide apart and ties to the railing of stairs and rapes her brutally.

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Iris (EP)

Iris is Miranda Sex Garden's second release, and first EP.

Track listing

Powerhouse (TV series)

PowerHouse is a United States television series produced by the Educational Film Center at Northern Virginia ETV and aired on PBS for 16 episodes in 1982 (two episodes never aired). It billed itself as "a 16-part series for young people and their families," with the target audience being primarily kids, preteens, teenagers,& young adults, and it was widely praised by educational groups. The series was later rerun by Nickelodeon in the mid-1980s.

Description

Set in Washington, DC, PowerHouse is focused on the adventures of a racially and ethnically diverse group of five teenagers and one adult from the inner city, based at a former boxing and sports gym headquarters turned community center for kids and teens. The center was founded by Brenda Gaines, a woman who inherited the place from her late father, a former boxing champion. The basic theme of the series is that every person is a source of creativity and power. “We all have a PowerHouse deep down inside,” it said in the theme song of the show.

Powerhouse (shop)

Powerhouse was a United Kingdom electrical goods retail chain which went into administration in 2003 and finally entered receivership in August 2006. At one time it was the third largest trader in the UK electrical goods market.

Company history and details

Powerhouse was born in 1992 from a management buyout of the retail arms of Southern Electric, Midlands Electricity and Eastern Electricity. The head office was based in Bicester. In an attempt to differentiate themselves in the market they positioned themselves as 'local experts' with each stores main sign bearing the towns name. To fill gaps in their product lineup many stores had concessions for Time Computers and their short-lived mobile phone arm Time Talk. There was also a close relationship with Sony - all stores up until the PRG buyout had 'Sony In-Store' sections where Sony products were isolated on backlit gondolas. nPower were also partners, with Powerhouse acting on their behalf to sign up new customers. This was a sound theory, as Powerhouse's strengths were in the MDA sectors and these deals helped their offering look competitive. However, Time Computers was not in good shape. Time Talk barely lasted 12 months. All Time concessions had closed by 2002 but were not officially refurbished. It was left to the individual store to best use the space as they saw fit.

Powerhouse (Mustasch album)

Powerhouse is the third full-length album by Swedish heavy metal band Mustasch. It was released in 2005 and peaked at number 10 on the Swedish charts.

Track listing

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