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Acoustic coupler

In telecommunications, an acoustic coupler is an interface device for coupling electrical signals by acoustical means—usually into and out of a telephone. The link is achieved through converting electric signals from the phone line to sound and reconvert sound to electric signals needed for the end terminal, such as a teletypewriter, back, rather than through direct electrical connection. Prior to its breakup in 1984, Bell System's legal monopoly over telephony in the United States allowed the company to impose strict rules on how consumers could access their network. Customers were sold by Bell to the network; the same set-up was operative in nearly all countries, where the telephone companies were nationally owned. In many households, telephones were hard-wired to wall terminals before connectors like RJ11 and BS 6312 became standardized; the situation was similar in other countries. In Australia, until 1975 the PMG, a Government monopoly, owned all telephone wiring and equipment in user premises and prohibited attachment of third party devices, while most handsets were connected by 600 series connectors, these were peculiar to Australia so imported equipment could not be directly connected in any case, despite the general electrical compatibility.

It was not until a landmark court ruling regarding the Hush-A-Phone in 1956 that the use of a phone attachment was allowed for the first time. A second court decision in 1968 regarding the Carterfone further allowed any device not harmful to the system to be connected directly to the AT&T network; this decision enabled the proliferation of innovations like answering machines, fax machines, modems. When inventors began developing devices to send non-voice signals over the telephone line, the need for a workaround for the Bell restrictions was apparent; as early as 1937, telefax machines used by newspapers were using some kind of couplers acoustic but more magnetic for single-directional communication. Multiplexed bidirectional telephone coupling was not needed by these early fax machines. Robert Weitbrecht created a workaround for the Bell restrictions in 1963, he developed a coupling device that converted sound from the ear piece of the telephone handset to electrical signals, converts the electrical pulses coming from the teletypewriter to sound that goes into the mouth piece of the telephone handset.

His acoustic coupler is known as the Weitbrecht Modem. The Weitbrecht Modem inspired other engineers to develop other modems to work with 8-bit ASCII terminals at a faster rate; such modems or couplers were developed around 1966 by John van Geen at the Stanford Research Institute, that mimicked handset operations. An early commercial model was built by Livermore Data Systems in 1968. One would dial the computer system on one's phone, when the connection was established, place the handset into the acoustic modem. Since the handsets were all supplied by the telephone company, most had the same shape, simplifying the physical interface. A microphone and a speaker inside the modem box would pick up and transmit the signaling tones, circuitry would convert those audio frequency-shift keying encoded binary signals for an RS232 output socket. With luck one could get 300 baud transmission rates; that speed was sufficient for typewriter-based terminals, as the IBM 2741, running at 134.5 baud, or a teleprinter, running at 110 baud.

The practical upper limit for acoustic-coupled modems was 1200-baud, first made available in 1973 by Vadic and 1977 by AT&T. 1200 baud endpoints became widespread in 1985 with the advent of the Hayes Smartmodem 1200A, though it used an RJ11 jack and was not an acoustic coupler. Such devices facilitated the creation of dial-up bulletin board systems, a forerunner of modern internet chat rooms, message boards, e-mail. A standard telephone handset was placed into a cradle, engineered to fit around the microphone and earpiece of the handset. A modem would modulate a loudspeaker in the cup attached to the handset's microphone, sound from the loudspeaker in the telephone handset's earpiece would be picked up by a microphone in the cup attached to the earpiece. In this way signals could be passed in both directions. Acoustic couplers were sensitive to external noise and depended on the widespread standardization of the dimensions of telephone handsets. Once they were made legal and the AT command set became standard for modems, direct electrical connections to telephone networks became the preferred method of attaching modems, the use of acoustic couplers dwindled.

Acoustic couplers were still used until at least the late 1990s by people travelling in areas of the world where electrical connection to the telephone network is illegal or impractical. Many models of TDDs still have a built-in acoustic coupler, which allow more universal use with pay phones and for 911 calls by deaf people. An acoustic coupler is prominently shown early in the 1983 film "WarGames", when character David Lightman places a telephone handset into the cradle of a film prop acoustic modem to accentuate the act of using telephone lines for interconnection to the developing computer networks of the period—in this case, a military command computer; the earliest major motion picture depicting an acoustic coupler was the 1968 Steve McQueen film Bullitt. Carterfone Federal Standard 1037C MIL-S

Naval Air Station Whiting Field – South

Naval Air Station Whiting Field – South known as South Whiting Field, is located three miles north of the central business district of Milton, in Santa Rosa County, United States. This military airport is owned by the US Navy, it is one of two airfields located at Naval Air Station Whiting Field, the other airfield being NAS Whiting Field – North. This airport is assigned a three-letter location identifier of NDZ by the Federal Aviation Administration, but it does not have an International Air Transport Association airport code. Whiting Field NAS-South has two runways and 12 helipads: Runway 5/23: 5,997 x 200 ft. Surface: Asphalt Runway 14/32: 6,001 x 200 ft. Surface: Asphalt Helipads H1,H2,H3,H4,H5: 100 x 100 ft. Surface: Asphalt Helipad H6: 75 x 100 ft. Surface: Asphalt Helipads H-A,B,C,D,E,F: 100 x 100 ft. Surface: Asphalt Naval Air Station Whiting Field NAS Whiting Field – North NAS Whiting Field NAS Whiting Field page at Pensacola Chamber of Commerce NAS Whiting Field page at FAA Airport Diagram, effective February 27, 2020 Resources for this U.

S. military airport: FAA airport information for NDZ AirNav airport information for KNDZ NOAA/NWS latest weather observations SkyVector aeronautical chart for KNDZ

Supersingular K3 surface

In algebraic geometry, a supersingular K3 surface is a K3 surface over a field k of characteristic p > 0 such that the slopes of Frobenius on the crystalline cohomology H2 are all equal to 1. These have been called Artin supersingular K3 surfaces. Supersingular K3 surfaces can be considered the most interesting of all K3 surfaces. More a smooth projective variety X over a field of characteristic p > 0 is called supersingular if all slopes of Frobenius on the crystalline cohomology Ha are equal to a/2, for all a. In particular, this gives the standard notion of a supersingular abelian variety. For a variety X over a finite field Fq, it is equivalent to say that the eigenvalues of Frobenius on the l-adic cohomology Ha are equal to qa/2 times roots of unity, it follows that any variety in positive characteristic whose l-adic cohomology is generated by algebraic cycles is supersingular. A K3 surface whose l-adic cohomology is generated by algebraic cycles is sometimes called a Shioda supersingular K3 surface.

Since the second Betti number of a K3 surface is always 22, this property means that the surface has 22 independent elements in its Picard group. From what we have said, a K3 surface with Picard number 22 must be supersingular. Conversely, the Tate conjecture would imply that every supersingular K3 surface over an algebraically closed field has Picard number 22; this is now known in every characteristic p except 2, since the Tate conjecture was proved for all K3 surfaces in characteristic p at least 3 by Nygaard-Ogus, Maulik and Madapusi Pera. To see that K3 surfaces with Picard number 22 exist only in positive characteristic, one can use Hodge theory to prove that the Picard number of a K3 surface in characteristic zero is at most 20. In fact the Hodge diamond for any complex K3 surface is the same, the middle row reads 1, 20, 1. In other words, h2,0 and h0,2 both take the value 1, with h1,1 = 20. Therefore, the dimension of the space spanned by the algebraic cycles is at most 20 in characteristic zero.

Another phenomenon which can only occur in positive characteristic is that a K3 surface may be unirational. Michael Artin observed that every unirational K3 surface over an algebraically closed field must have Picard number 22. Conversely, Artin conjectured; this is now known in every characteristic except 3. Artin's conjecture was proved in characteristic 2 by Rudakov & Shafarevich, in every characteristic p at least 5 by Liedtke. Another proof for p at least 5 has been given by Lieblich; the first example of a K3 surface with Picard number 22 was given by Tate, who observed that the Fermat quartic w4 + x4 + y4 + z4 = 0has Picard number 22 over algebraically closed fields of characteristic 3 mod 4. Shioda showed that the elliptic modular surface of level 4 in characteristic 3 mod 4 is a K3 surface with Picard number 22, as is the Kummer surface of the product of two supersingular elliptic curves in odd characteristic. Shimada showed. In the case of characteristic 2 the double cover may need to be an inseparable covering.

The discriminant of the intersection form on the Picard group of a K3 surface with Picard number 22 is an power p2eof the characteristic p, as was shown by Artin and Milne. Here e is called the Artin invariant of the K3 surface. Artin showed that 1 ≤ e ≤ 10. There is a corresponding Artin stratification of the moduli spaces of supersingular K3 surfaces, which have dimension 9; the subspace of supersingular K3 surfaces with Artin invariant e has dimension e − 1. In characteristic 2, z2 = f,for a sufficiently general polynomial f of degree 6, defines a surface with 21 isolated singularities; the smooth projective minimal model of such a surface is a unirational K3 surface, hence a K3 surface with Picard number 22. The largest Artin invariant here is 10. In characteristic 3, z3 = g,for a sufficiently general polynomial g of degree 4, defines a surface with 9 isolated singularities; the smooth projective minimal model of such a surface is again a unirational K3 surface, hence a K3 surface with Picard number 22.

The highest Artin invariant in this family is 6. Dolgachev & Kondō described the supersingular K3 surface in characteristic 2 with Artin number 1 in detail. If the characteristic p is greater than 2, Ogus showed that every K3 surface S with Picard number 22 and Artin invariant at most 2 is a Kummer surface, meaning the minimal resolution of the quotient of an abelian surface A by the mapping x ↦ − x. More A is a supersingular abelian surface, isogenous to the product of two supersingular elliptic curves. K3 surface Tate conjecture Artin, Michael, "Supersingular K3 surfaces", Annales Scientifiques de l'École Normale Supérieure, Série 4, 7: 543–567, MR 0371899 Charles, F. "The Tate conjecture for K3 surfaces over finite fields", Inventiones Mathematicae, 194: 119–145, arXiv:1206.4002, Bibcode:2013InMat.194..119C, doi:10.1007/s00222-012-0443-y, MR 3103257 Dolgachev, I.. "A supersingular K3 surface in characteristic 2 and the Leech lattice", Int. Math. Res. Not.: 1–23, arXiv:math/0112283, Bibcode:2001math.....12283D, MR 1935564 Lieblich, M.

On the unirationality of supersingular K3 surfaces, arXiv:1403.3073, Bibcode:2014arXiv1403.3073L Liedtke, C. "Supersingular K3 surfaces are unirational", Inventiones Mathematicae, 200: 979–1014, arX

Detroit Economic Club

The Detroit Economic Club, headquartered at 211 West Fort Street in downtown Detroit, was formed in 1934 as a platform for the discussion and debate of important business and social issues. It is known internationally as a top speaking forum for prominent business and government officials, who address members and their guests at the Club's 35-meeting season. With more than 3,500 members, the DEC is a forum for vital issues; the DEC claims to have hosted every sitting U. S. President since Richard Nixon and is ranked among the top speaking platforms in the world; the DEC is one of the most valued podiums for CEO's in the world and one of the top five executive speaking forums in America. The Detroit Economic Club was founded in 1934 by Allen Crow; the objective of the Club was and still is: to promote an interest in, to enlighten its members on important governmental and societal issues. The growth in the Club was rapid with 275 men joining. "men" because women were not admitted until 1973. That was the year.

Within five years of the inception, the Club's membership had grown to 1,100 and post World War II the membership was approaching 2,000. The logo of the Club is an Aladdin's Lamp, which Crow selected it because it was the Greek symbol for enlightenment; that is. Born out of the Depression, the Club tends to succeed when the economy is not. Founder, Allen Crow, had a big idea: "Maybe if you gathered a lot of smart people in one room, on a regular basis, they could figure the way out." The main activity of the Club is is in the form of a breakfast or lunch/business meeting setting. The Club presents, on average, 35 meetings per year. Where the speaker take the podium/stage and address whatever their topic is at that time. Speakers speak for about 20–30 minutes and there is reserved times for networking and questions. Traditionally, the club would meet on Mondays; the history goes back before commercial air travel and the meetings were scheduled by Allen Crow on Monday's so that the speakers could travel to Detroit by train over the weekend and this would conserve their weekly business time.

Annual dues were $5.00 and tickets were $1.50. Over the years the dues have increased to keep pace with inflation and growth. Now the Club has five categories of memberships ranging from Young Leader dues at $75.00 to Gold Membership at $500.00. The Club's meeting place was and still are some of the same venues from the early stages of the Club such as: the Book Cadillac Hotel, a number of the Club's meetings took place at Cobo Hall, is still a principal location. How The Club obtain speakers, is asked. In early days, they did pay. Now, the speakers come because they welcome the opportunity to address the Club's prestigious forum, for the extensive outreach they know their message will receive. In addition to the newspaper coverage that the speakers receive, a number of radio stations use to broadcast the meetings and was carried to about 400,000 Metro-Detroit area homes. Now, there is still the newspaper and radio coverage, but by technology advancing the way that it has, the Club sometimes have a live-stream for viewers at home or members on the road.

The Club has always pushed to obtain some of the region's most prominent and well spoken leaders around the globe. To be fair, The Club has hosted a meeting with every President of the United States since former President Nixon; the first woman speaker at the DEC was Catherine Curtis on November 1, 1937 and she spoke on "The Housewife as Capitalist." The first Black speaker was Lester Granger, President of the National Urban League on January 19, 1948. In addition to those groundbreaking speakers, there has been a number of international level leaders as well to grace the Club with their wisdom and words of enlightenment such as: Soviet Ambassador to the U. S. Antoly Dobrynin, Bruno Kreisky when he was the Australian Chancellor, Ambassador of the Republic of Cuba to the U. S. Jose Ramon Cabanas Rodriguez, countless others; the President of the Club was the chief operating officer as well as the president. Nowadays, those titles and tasks are handled by two separate individuals with the same goal in mind.

Since the first President and Founder, Allen B. Crow, there has been nine other fantastic Leaders of this great Club. Lester Skene Bork, Walker Lee Cisler, Russel A. Swaney, Theodore H. Mecke, Jr. Wesley R. Johnson, Gerald E. Warren, William R. Halling, Elizabeth "Beth" Chappell, who served the Club for 15 years, the second longest term after the Founder, Allen B. Crow; the current President and CEO of the Club is Steve Grigorian, who has served since 2017. The Young Leader Program has been growing over the years since its launch in 2007; the Young Leader members are made up of over 1,200 young professionals in out of the Metro-Detroit area. All YL members are under the age of 40 years, the only requirement to join the Young Leaders program. Not only do are the YL members allowed to regular DEC meetings, but have their own Young Leader Series meetings of their own. In addition to hosting an annual Young Leader Conference; the Young Leader program is continuously growing with more young professionals who are invested into the economic and political future of

Mr. Hill

Todd Gumke, better known by his stage name Mr. Hill, is an American hip hop record producer and DJ from Seattle, Washington. Mr. Hill has produced for the likes of Kool Keith, Mr. Lif, Boom Bap Project and Grayskul, among others, he is a member of the Pacific Northwest hip hop collective Oldominion. Mr. Hill's first production credit was in 1999, for the song "Investigation Zero" for another Pacific Northwest hip hop artist named Footprints; the song appeared on the 1999 cassette tape Operation Raw. While he was DJing at the time, he focused more on producing. Through making connections in the local circuit, he met Onry Ozzborn, who would be a frequent collaborator of Mr. Hill's, with Onry inviting Mr. Hill to join Oldominion. Following encounters and discussions Grayskul had with Slug and other Rhymesayers Entertainment members, Grayskul's album Deadlivers was released on the label in 2005. Mr. Hill produced over half the album, taking on the Moniker "Phanton", while Onry Ozzborn took "Reason" and JFK to "Recluse".

In 2006, he released Snaps. The album features Boom Bap Project and Onry Ozzborn, among others; the same year he released the album Nite Owls. The next year, Mr. Hill released his first instrumental album The Darkest Hour via Hal Cush Music. In 2011, he released the album SMiRK, an instrumental album mixing electronic and hip hop elements. Studio albums Snaps The Darkest Hour SMiRK Collaborative albums Nite Owls EPs Night Time Dreamers Productions Onry Ozzborn - "Listen & Learn", "The Ozz", "Legend Had It", "Poltergeist", "717" and "The Zone" from The Grey Area Sirens Echo - "Hands Together" from Psalms Of The Sirens Grayskul - "You People", "Adversarial Theatre Of Justice", "Action Figure Of Speech", "Once Upon A Time", "Do They Exist", "Vixen", "After Hours", "The Skul", "Prom Quiz", "Deadlivers" and "Secret Wars" from Deadlivers Boom Bap Project - "Sounds Of The Street" and "War Of Roses" from Reprogram Boom Bap Project - "The Struggle" from The Shakedown Coley Cole - "Goldplated Straitjackets" from Goldplated Straitjackets Onry Ozzborn - "Part 3", "Part 4" and "Educated Guess" from In Between Syndel - "Ring Side" from Enchantress Grayskul - "The Last Lullaby" from Bloody Radio Mr. Lif - "Presidential Report" Onry Ozzborn - "No Hoax" and "76" from No Hoax Destro - "That's That", "Yah, Yah" and "Oldominion Coming Thru" from ill.ustrated Onry Ozzborn - "Electric Dreams" from Hold On for Dear Life Mr. Hill on Bandcamp Mr. Hill on Discogs

Charles Lockey

Charles Lockey was an English singer. A tenor, he is known as a soloist in the first performance of Mendelssohn's oratorio Elijah, he was born in Thatcham on 20 March 1820, son of Angel Lockey of Oxford. He was a choirboy at Magdalen College, Oxford from 1828 to 1836, afterwards studied singing with Edward Harris at Bath. Lockey sang in the choirs of St George's Chapel and Eton College Chapel. In 1843 he became a vicar-choral of St Paul's Cathedral, his first public appearance in oratorio was in October 1842, when he sang in Rossini's Stabat Mater for the Melophonic Society. In 1848 he was appointed a Gentleman of the Chapel Royal, he performed at the Concerts of Antient Music in 1846. In 1846 Lockey was engaged for the Birmingham Festival: in the first performance, on 26 August, of Mendelssohn's oratorio Elijah he sang "Then shall the righteous". Mendelssohn, on hearing him rehearse the song, asked him to sing "If with all your hearts", assigned to another singer. "A young English tenor," the composer wrote in a letter, "sang the last air so beautifully that I was obliged to collect myself to prevent my being overcome, to enable me to beat time steadily."On 24 May 1853 he married Martha Williams, a contralto singer.

They had John. Lockey retired from public life about 1862, on account of a throat disorder, entered into business at Gravesend and Dover, he nominally held his position at St Paul's until his death, but for forty-three years Fred Walker, Joseph Barnby, Edward Lloyd were his deputies. He died on 3 December 1901 in Hastings. Attribution This article incorporates text from a publication now in the public domain: Corder, Frederick. "Lockey, Charles". In Lee, Sidney. Dictionary of National Biography. 2. London: Smith, Elder & Co. p. 473. Portraits of Charles Lockey at the National Portrait Gallery, London