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Movements, leaders, victories and the continuing fight for equality.
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Explore the people, places, events, achievements, struggles and stories that shaped our journey.
Movements, leaders, victories and the continuing fight for equality.
Innovation, patents, science, technology and world-changing contributions.
Pioneers, champions, Negro Leagues, records, activism and excellence.
Meet the people whose lives, choices and achievements shaped the journey.
Black towns, communities, institutions and places where history happened.
Moments that changed communities, movements, institutions and the nation.
In 1968 Shirley Chisholm became the first Black woman elected to the United States Congress. In 1972 she launched a campaign for the Democratic presidential nomination, breaking another political barrier.
MORE →Reflects the personal views, recollections, and perspective of the author, Mike Davis.
This is a personal recollection on the Move fire on May 13, 1985
The inch per second is a unit of speed or velocity. It expresses the distance in inches (in) traveled or displaced, divided by time in seconds (s). The corresponding coherent SI unit is the metre per second.[1]
Abbreviations include in/s,[1] ips,[1] and less frequently, in⋅s−1.
1 inch per second is:
Conversion to inches per second:
In magnetic tape sound recording, magnetic tape speed is often quoted in inches per second (abbreviated "ips").
In computer mice sensitivity is also often referred to in inches per second (abbreviated as "ips").
In rotorcraft health monitoring, rotor and shaft induced vibration levels are often quoted in inches per second.
Source: Wikipedia. Article content is retrieved live through the MediaWiki API.
The inch per second is a unit of speed or velocity. It expresses the distance in inches (in) traveled or displaced, divided by time in seconds (s). The corresponding coherent SI unit is the metre per second. Abbreviations include in/s, ips, and less frequently, in⋅s−1.
In pyrotechnics, black match is a type of crude fuse, constructed of cotton or polyester string fibers intimately coated with a slurry made of black powder and a binder like dextrin, then dried. It typically burns at a rate of one inch per second, though this rate is dependent on the quality of black powder used.
From 1963 to 1970, Ampex manufactured several models of VTR 2-inch helical VTRs, capable of recording and playing back analog black and white video. Recording employed non-segmented helical scanning, with one wrap of the tape around the video head drum being a little more than 180 degrees, using two video heads. One video drum rotation time was two fields of video. The units had two audio tracks recorded on the top edge of the tape, with a control track recorded on the tape's bottom edge. The 2-inch-wide video tape used was one mil (0.001 in or 0.0254 mm) thick. The VTRs were mostly used by industrial companies, educational institutions, and a few for in-flight entertainment. The capstan tape speed is 3.7 inches per second (5,600 mm/min), which provided a long record time of up to five hours on large reels. The units were 100% solid state. The Ampex 2-inch helical VTRs were popular, as they were priced much less than the 2-inch quadruplex videotape recorders used in the broadcast television industry at the time.
Video Cassette Recording (VCR) is an early domestic analog recording format designed by Philips. It was the first successful consumer-level home videocassette recorder (VCR) system. Later variants included the VCR-LP and Super Video (SV) formats. The VCR format was introduced in 1972, just after the Sony U-matic format in 1971. Although at first glance the two might appear to have been competing formats, they were aimed at very different markets. After failing as a consumer format, U-matic was marketed as a professional television production format, whilst VCR was targeted particularly at educational but also domestic users. Unlike some other early formats such as Cartrivision, the VCR format does record a high-quality video signal without resorting to Skip field. Home video systems had previously been available, but they were open-reel systems (such as the Sony CV-2000) and were expensive to both buy and operate. They were also unreliable and often only recorded in black and white such as the EIAJ-1. The VCR system was easy to use and recorded in color but was still expensive: when it was introduced in 1972 the N1500 recorder cost nearly £600 (equivalent to £7,100 in 2025). By comparison, a small car (the Morris Mini) could be purchased for just over £600. The VCR format used large square cassettes with 2 co-axial reels, one on top of the other, containing 1⁄2-inch-wide (12.7 mm) chrome dioxide magnetic tape. Three playing times were available: 30, 45 and 60 minutes. The 60-minute videocassettes proved very unreliable, suffering numerous snags and breakages due to the very thin 17-micrometre (0.67-mil) video tape. Tapes of 45 minutes or less contained 20-micrometre (0.79-mil) thickness tape. The mechanically complicated recorders themselves also proved somewhat unreliable. One particularly common failing occurred should tape slack develop within the cassette; the tape from the top (takeup) spool may droop into the path of the bottom (supply) spool and become entangled in it if rewind was selected. The cassette would then completely jam and require dismantling to clear the problem, and the tape would then be creased and damaged. The system predated the development of the slant azimuth technique to prevent crosstalk between adjacent video tracks, so it had to use an unrecorded guard band between tracks. This required the system to run at a tape speed of 14.29 cm/s (5.63 inches per second). 6.56 cm/s (2.58 inches per second) was the speed of the long play variant. 3.95 cm/s (1.56 inches per second) was the speed of Grundig's Super Video variant. The Philips VCR system brought together many advances in video recording technology to produce the first truly practical home video cassette system. The very first Philips N1500 model included all the essential elements of a domestic video cassette recorder: Simple loading of cassette and simple operation using "Piano Key" controls, with full auto-stop at tape ends. A tuner for recording off-air television programmes. A clock with timer for unattended recordings. A modulator to allow connection to a normal (for the time) television receiver without audio and video input connectors. The Philips VCR system was marketed only in the UK, mainland Europe, Australia and South Africa. In mid-1977, Philips announced they were considering distribution of the format in North America, and it was test marketed for several months. Because the format was initially designed only for use with the 625-line 50-hertz (3,000 rpm) PAL system, VCR units had to be modified in order to work with the 60-hertz (3,600 rpm) NTSC system. The tape speed had to be increased by 20% to accommodate the higher frame rate of NTSC, which resulted in a 60-minute PAL tape running for 50 minutes in a NTSC machine. DuPont announced a thinner videotape formulation that would allow a 60-minute NTSC VCR tape (and roughly 70 minutes in PAL), but the tape was even less reliable than previous formulations. Ultimately, Philips abandoned any hope of trying to sell their VCR format in North America, partly because of the reliability issues, and partly because of the introduction of VHS that same year.
Before the 1921 destruction of Tulsa’s Greenwood District, Black residents had created a remarkable center of business and community life. The district included stores, professional offices, entertainment venues and homes owned by Black citizens. Understanding Greenwood means learning what was built—not only what was burned.
MORE →Shirley Chisholm, elected in 1968.