In physics and fluid mechanics, a boundary layer is an important concept and refers to the layer of fluid in the immediate vicinity of a bounding surface where the effects of viscosity are significant. In the Earth's atmosphere, the atmospheric boundary layer is the air layer near the ground affected by diurnal heat, moisture or momentum transfer to or from the surface. On an aircraft wing the boundary layer is the part of the flow close to the wing, where viscous forces distort the surrounding non-viscous flow. Laminar boundary layers can be loosely classified according to their structure and the circumstances under which they are created; the thin shear layer which develops on an oscillating body is an example of a Stokes boundary layer, while the Blasius boundary layer refers to the well-known similarity solution near an attached flat plate held in an oncoming unidirectional flow and Falkner–Skan boundary layer, a generalization of Blasius profile. When a fluid rotates and viscous forces are balanced by the Coriolis effect, an Ekman layer forms.
In the theory of heat transfer, a thermal boundary layer occurs. A surface can have multiple types of boundary layer simultaneously; the viscous nature of airflow reduces the local velocities on a surface and is responsible for skin friction. The layer of air over the wing's surface, slowed down or stopped by viscosity, is the boundary layer. There are two different types of boundary layer flow: turbulent. Laminar boundary layer flow The laminar boundary is a smooth flow, while the turbulent boundary layer contains swirls or "eddies." The laminar flow is less stable. Boundary layer flow over a wing surface begins as a smooth laminar flow; as the flow continues back from the leading edge, the laminar boundary layer increases in thickness. Turbulent boundary layer flow At some distance back from the leading edge, the smooth laminar flow breaks down and transitions to a turbulent flow. From a drag standpoint, it is advisable to have the transition from laminar to turbulent flow as far aft on the wing as possible, or have a large amount of the wing surface within the laminar portion of the boundary layer.
The low energy laminar flow, tends to break down more than the turbulent layer. The aerodynamic boundary layer was first defined by Ludwig Prandtl in a paper presented on August 12, 1904 at the third International Congress of Mathematicians in Heidelberg, Germany, it simplifies the equations of fluid flow by dividing the flow field into two areas: one inside the boundary layer, dominated by viscosity and creating the majority of drag experienced by the boundary body. This allows a closed-form solution for the flow in both areas, a significant simplification of the full Navier–Stokes equations; the majority of the heat transfer to and from a body takes place within the boundary layer, again allowing the equations to be simplified in the flow field outside the boundary layer. The pressure distribution throughout the boundary layer in the direction normal to the surface remains constant throughout the boundary layer, is the same as on the surface itself; the thickness of the velocity boundary layer is defined as the distance from the solid body to the point at which the viscous flow velocity is 99% of the freestream velocity.
Displacement thickness is an alternative definition stating that the boundary layer represents a deficit in mass flow compared to inviscid flow with slip at the wall. It is the distance by which the wall would have to be displaced in the inviscid case to give the same total mass flow as the viscous case; the no-slip condition requires the flow velocity at the surface of a solid object be zero and the fluid temperature be equal to the temperature of the surface. The flow velocity will increase within the boundary layer, governed by the boundary layer equations, below; the thermal boundary layer thickness is the distance from the body at which the temperature is 99% of the freestream temperature. The ratio of the two thicknesses is governed by the Prandtl number. If the Prandtl number is 1, the two boundary layers are the same thickness. If the Prandtl number is greater than 1, the thermal boundary layer is thinner than the velocity boundary layer. If the Prandtl number is less than 1, the case for air at standard conditions, the thermal boundary layer is thicker than the velocity boundary layer.
In high-performance designs, such as gliders and commercial aircraft, much attention is paid to controlling the behavior of the boundary layer to minimize drag. Two effects have to be considered. First, the boundary layer adds to the effective thickness of the body, through the displacement thickness, hence increasing the pressure drag. Secondly, the shear forces at the surface of the wing create skin friction drag. At high Reynolds numbers, typical of full-sized aircraft, it is desirable to have a laminar boundary layer; this results in a lower skin friction due to the characteristic velocity profile of laminar flow. However, the boundary layer thickens and becomes less stable as the flow develops along the body, becomes turbulent, the process known as boundary layer transition. One way of dealing with this problem is to suck the boundary layer away through a porous surface; this can reduce drag, but is impractical due to its mechanical complexity and the power required to move the air and dispose of it.
Natural laminar flow techniques push the boundary layer transition aft by reshaping the airfoil or fuselage so
Frank Joseph Malina was an American aeronautical engineer and painter known for becoming both a pioneer in the art world and the realm of scientific engineering. Malina was born in Texas, his father came from Bohemia. Frank's formal education began with a degree in mechanical engineering from Texas A&M University in 1934. In 1935, while a graduate student at the California Institute of Technology, Malina persuaded Professor of Aeronautics Theodore von Kármán to allow him to pursue studies into rocketry and rocket propulsion; the formal goal was development of a sounding rocket. Malina and five associates became known at Caltech as the "Suicide Squad" because of their dangerous experiments when testing rocket motor designs. Malina's group was forced to move their operations away from the main Caltech campus into the more remote Arroyo Seco; this site and the research Malina was conducting would become the Jet Propulsion Laboratory. Malina served as the second Director of JPL. In 1939, the Société astronomique de France awarded Malina the Prix d'Astronautique for his contribution to the study of interplanetary travel and astronautics.
In 1942, von Kármán, Malina and three other students started the Aerojet Corporation. By late 1945, Malina's rockets had outgrown the facility at Arroyo Seco, his tests were moved to White Sands Missile Range in New Mexico. Here, the project's WAC Corporal sounding rocket was the first U. S. rocket becoming the first sounding rocket to reach space. During 1947, with rocket research in high gear, Malina's demanding travel and administrative schedule, along with a dislike of so much rocketry research being devoted to weapons systems and not scientific research, caused him to re-evaluate his career and leave Aerojet. Malina's passing interest in the Communist Party and labor activism while he was a graduate student in the 1930s had attracted the attention of the FBI, he moved to France and joined the fledgling United Nations as secretariat of the United Nations Educational and Cultural Organization under Julian Huxley. In 1951, Malina became head of UNESCO's division of scientific research. Two years Malina left UNESCO to pursue an interest in kinetic art.
In 1952, at the height of the Red Scare, Malina was indicted for having failed to list his Communist Party membership on an old security questionnaire from Caltech. He was declared a fugitive, to be arrested if and when he returned to the United States. In 1968 in Paris he founded Leonardo, an international peer-reviewed research journal that featured articles written by artists on their own work, focused on the interactions between the contemporary arts with the sciences and new technologies; the Leonardo journal is still published as of 2018 as a project of Leonardo/ISAST, the International Society for the Arts and Technology. In 1990, Malina was inducted into the International Space Hall of Fame. Frank Malina died in 1981 near Paris, France, his widow Marjorie Duckworth Malina died in 2006. Their sons Roger and Alan Malina work in France and Portugal, respectively. Guggenheim Aeronautical Laboratory Qian Xuesen "Malina, Frank Joseph". American National Biography.'Frank Malina On Line Archive' Biography at the Wayback Machine Frank Malina timeline Leonardo Journal JPL history MG Lord.
Astro Turf: The Private Life of Rocket Science. New York: Walker & Company. ISBN 0-8027-1427-7. Includes a detailed account of Malina's post-JPL life, by a scholar who had access to his FBI file "Propulsion" –– The documentary, Huffington Post
Columbia is a city in the U. S. state of Missouri. It is home to the University of Missouri. Founded in 1821, it is the principal city of the five-county Columbia metropolitan area, it is Missouri's fourth most-populous and fastest growing city, with an estimated 121,717 residents in 2017. As a Midwestern college town, Columbia has a reputation for progressive politics, persuasive journalism, public art; the tripartite establishment of Stephens College, the University of Missouri, Columbia College, which surround the city's Downtown to the east and north, has made the city a center of learning. At its center is 8th Street known as the Avenue of the Columns, which connects Francis Quadrangle and Jesse Hall to the Boone County Courthouse and the City Hall. An agricultural town, the cultivation of the mind is Columbia's chief economic concern today. Never a major center of manufacturing, the city depends on healthcare and technology businesses. Companies such as Shelter Insurance and Slackers CDs and Games, were founded in the city.
Cultural institutions include the State Historical Society of Missouri, the Museum of Art and Archaeology, the annual True/False Film Festival. The Missouri Tigers, the state's only major college athletic program, play football at Faurot Field and basketball at Mizzou Arena as members of the rigorous Southeastern Conference; the city rests upon the forested hills and rolling prairies of Mid-Missouri, near the Missouri River valley, where the Ozark Mountains begin to transform into plains and savanna. Limestone forms bluffs and glades while rain dissolves the bedrock, creating caves and springs which water the Hinkson, Roche Perche, Bonne Femme creeks. Surrounding the city, Rock Bridge Memorial State Park, Mark Twain National Forest, Big Muddy National Fish and Wildlife Refuge form a greenbelt preserving sensitive and rare environments; the first humans who entered the area at least twelve thousand years ago were nomadic hunters. Woodland tribes lived in villages along waterways and built mounds in high places.
The Osage and Missouria nations were expelled by the exploration of French traders and the rapid settlement of American pioneers. The latter arrived by the Boone's Lick Road and hailed from the culture of the Upland South Virginia and Tennessee. From 1812 on the Boonslick area would play a pivotal role in Missouri's early history and the nation's westward expansion. German and other European immigrants soon joined; the modern populace is unusually diverse, over eight percent foreign-born. While White and Black remain the largest ethnicities, people of Asian descent are now the third-largest group; the city has been called the "Athens of Missouri" for its classic beauty and educational emphasis, but is more called "CoMo". Columbia's origins begin with the settlement of American pioneers from Kentucky and Virginia in an early 1800s region known as the Boonslick. Before 1815 settlement in the region was confined to small log forts because of the threat of Native American attack during the War of 1812.
When the war ended settlers came on foot and wagon moving entire households along the Boone's Lick Road and sometimes bringing enslaved African Americans. By 1818 it was clear that the increased population would necessitate a new county be created from territorial Howard County; the Moniteau Creek on the west and Cedar Creek on the east were obvious natural boundaries. Believing it was only a matter of time before a county seat was chosen, the Smithton Land Company was formed to purchase over 2,000 acres to established the village of Smithton near the present-day intersection of Walnut and Garth. In 1819 Smithton was a small cluster of log cabins in an ancient forest of hickory. In 1820 Boone County was formed and named after the deceased explorer Daniel Boone; the Missouri Legislature appointed John Gray, Jefferson Fulcher, Absalom Hicks, Lawrence Bass, David Jackson as commissioners to select and establish a permanent county seat. Smithton never had more than twenty people, it was realized that well digging was difficult because of the bedrock.
Springs were discovered across the Flat Branch Creek, so in the Spring of 1821 Columbia was laid off and the inhabitants of Smithton moved their cabins to the new town. The first house in Columbia was built by Thomas Duly in 1820 at what would become Fifth and Broadway. Columbia's permanence was ensured when it was chosen as county seat in 1821 and the Boone's Lick Road was rerouted down Broadway; the roots of Columbia's three economic foundations—education and insurance— can be traced to the city's incorporation in 1821. Original plans for the town set aside land for a state university. In 1833, Columbia Baptist Female College opened, which became Stephens College. Columbia College, distinct from today's and to become the University of Missouri, was founded in 1839; when the state legislature decided to establish a state university, Columbia raised three times as much money as any competing city, James S. Rollins donated the land, today the Francis Quadrangle. Soon other educational institutions were founded in Columbia, such as Christian Female College, the first college for women west of the Mississippi, which became Columbia College.
The city benefited from being a stagecoach stop of the Santa Fe and Oregon trails, from the Missouri–Kansas–Texas Railroad. In 1822, William Jewell set up the first hospital. In 1830, the first newspaper began.
Compton College is a public community college in Compton, California. From 2006 when it lost its regional accreditation to 2017 when it regained that accreditation, it operated as a part of El Camino College Prior to and subsequent to the partnership with El Camino College, the college was operated by the Compton Community College District. Compton Community College was established in 1927 as a component of the Compton Union High School District. From 1932 to 1949, it operated as a four-year junior college, incorporating the last two years of high school as well as the first two years of college. In 1933 the campus was devastated by a major earthquake which struck the region, leaving two buildings standing. Nobody on campus was killed. In the 1940s several thousand Compton College students entered the armed forces and during World War II the campus housed a military unit and a defense plant. In 1950 voters approved a bond issue separating the college from the high school district; the new college campus was constructed at the college's present site, 1111 East Artesia Boulevard.
Classes began on the new campus in the Fall of 1953. In the 1960s the composition of the student body changed from predominantly Caucasian to overwhelmingly African-American; as a result, it has sometimes been called "California’s black college."In 1970 the Board of Trustees appointed the institution's first African-American President/Superintendent, Dr. Abel B. Sykes, Jr. Highlights during his 14-year administration included the construction of the first two new campus buildings since 1952: the Jane Astredo Allied Health Building and the Abel B. Sykes, Jr. Child Development Center; the 1980s was a period of reduced funding and partial retrenchment for the institution, but by the early 1990s the college had once again stabilized. The second major demographic shift occurred in the 1990s making the campus population 50% African-American and 50% Hispanic. In 1996 the Board appointed Ulis C. Williams as Interim President/Superintendent and in January, 1997 made this appointment permanent. In 2004 the college began experiencing significant turmoil caused by a "corrupt board and financial insolvency".
In May 2004, the state installed Arthur Tyler, Jr. as Special Trustee to assist the Compton Community College District toward achieving fiscal stability and integrity. Subsequently, in August, the State Chancellor issued another Executive Order authorizing the continuing authority of the Special Trustee to manage the College, to suspend, for up to one year, the powers of the governing board of the College, or of any members of that board, to exercise any powers or responsibilities or to take any official action with respect to the management of the College. Interim President/Superintendent, Dr. Rita Cepeda was hired in February, 2005 to assist with the recovery of the College; the following year, the Executive Director of the Accrediting Commission for Community and Junior Colleges, Dr. Barbara Beno informed the College of the Commission's decision to terminate the College's accreditation. In July, 2005, the State Chancellor assigned Dr. Jamillah Moore, Senior Vice Chancellor of the California Community Colleges system as the interim President/Superintendent and Dr. Charles Ratliff as the Special Trustee with the impending departure of both Dr. Cepeda and Mr. Tyler.
The College began its appeal to the Commission regarding the termination decision. On March 1, 2006, a third Special Trustee, Mr. Thomas Henry, was assigned to the College District to continue with the implementation of AB 61 and the development of AB 318 to keep the doors open for students. On June 30, 2006, Governor Arnold Schwarzenegger signed AB 318 into law giving the College District $30 million loan for recovery and the opportunity to partner with a college of good standing to offer accredited courses; the bill gave the Fiscal Crisis and Management Assistance Team the responsibilities to conduct a comprehensive assessment and to develop a recovery plan for the College to regain its accreditation. Five months the Special Trustee approved the Memorandum of Understanding with El Camino College District to solidify the partnerships between the two districts. Under this MOU, the campus became a center of El Camino College; the Office of the President/Superintendent was replaced by the Office of Provost/Chief Executive Officer.
The center is established as the Compton Community Educational Center. At midnight, Compton Community College lost its accreditation. Shortly thereafter, the Compton Community Educational Center became part of El Camino College with Dr. Doris P. Givens serving as the Provost/CEO. Dr. Lawrence M. Cox became Provost/CEO from 2008 to 2010. On June 7, 2017, Compton College was restored to full accreditation; this followed years of rebuilding under president Keith Curry, provost of the campus while it was partnered with El Camino College. The 40,000-square-foot library on campus opened in 2014, its opening was scheduled for 2007. At that time it had a cost of $25 million; the opening was delayed by seven years and with an additional $4 million spent due to violations in the building code. For the period it was renovated. Billy Anderson, NFL player Memo Arzate, retired professional soccer player Don Bandy, football player, Washington Redskins Justin Carter basketball player for Maccabi Kiryat Gat of the Israeli Premier League James Coburn, American actor, famous for his "Cool" tough-guy roles Coolio, American rap artist Yuri Kochiyama, Japanese-American Human Rights Activist Iva Toguri D'Aquino, Tokyo Rose Louella Daetweiler, All-American Girls Professional Baseball League player Jamaa Fanaka, filmmaker Snoop Dogg, rap arti
Virtual International Authority File
The Virtual International Authority File is an international authority file. It is a joint project of several national libraries and operated by the Online Computer Library Center. Discussion about having a common international authority started in the late 1990s. After a series of failed attempts to come up with a unique common authority file, the new idea was to link existing national authorities; this would present all the benefits of a common file without requiring a large investment of time and expense in the process. The project was initiated by the US Library of Congress, the German National Library and the OCLC on August 6, 2003; the Bibliothèque nationale de France joined the project on October 5, 2007. The project transitioned to being a service of the OCLC on April 4, 2012; the aim is to link the national authority files to a single virtual authority file. In this file, identical records from the different data sets are linked together. A VIAF record receives a standard data number, contains the primary "see" and "see also" records from the original records, refers to the original authority records.
The data are available for research and data exchange and sharing. Reciprocal updating uses the Open Archives Initiative Protocol for Metadata Harvesting protocol; the file numbers are being added to Wikipedia biographical articles and are incorporated into Wikidata. VIAF's clustering algorithm is run every month; as more data are added from participating libraries, clusters of authority records may coalesce or split, leading to some fluctuation in the VIAF identifier of certain authority records. Authority control Faceted Application of Subject Terminology Integrated Authority File International Standard Authority Data Number International Standard Name Identifier Wikipedia's authority control template for articles Official website VIAF at OCLC
Douglas SBD Dauntless
The Douglas SBD Dauntless is a World War II American naval scout plane and dive bomber, manufactured by Douglas Aircraft from 1940 through 1944. The SBD was the United States Navy's main carrier-based scout/dive bomber from mid-1940 through mid-1944; the SBD was flown by the United States Marine Corps, both from land air bases and aircraft carriers. The SBD is best remembered as the bomber that delivered the fatal blows to the Japanese carriers at the Battle of Midway in June 1942; the type earned its nickname "Slow But Deadly" during this period. During its combat service, the SBD proved to be an excellent naval scout dive bomber, it possessed long range, good handling characteristics, potent bomb load, great diving characteristics, good defensive armament and ruggedness. One land-based variant of the SBD — in omitting the arrestor hook — was purpose-built for the U. S. Army Air Forces, as the A-24 Banshee. Design work on the Northrop BT-1 began in 1935. In 1937, the Northrop Corporation was taken over by Douglas, the active Northrop projects continued under Douglas Aircraft Corporation.
The Northrop BT-2 was developed from the BT-1 by modifications ordered in November 1937, provided the basis of the SBD, which first entered service in mid-1939. Ed Heinemann led a team of designers who considered a development with a 1,000 hp Wright Cyclone engine; the plane was developed at the Douglas El Segundo, CA plant, that facility, along with the company's Oklahoma City plant, built all the SBDs produced. One year earlier, both the U. S. Navy and Marine Corps had placed orders for the new dive bomber, designated the SBD-1 and SBD-2; the SBD-1 went to the Marine Corps in late 1940, the SBD-2 to the Navy in early 1941. The distinctive perforated split flaps or "dive-brakes" had been incorporated into the BT-1 to eliminate tail buffeting during diving maneuvers; the next version was the SBD-3, which began manufacture in early 1941. It had increased armor, self-sealing fuel tanks, four machine guns; the SBD-4 provided a 12-volt electrical system, a few were converted into SBD-4P reconnaissance aircraft.
The next version, the SBD-5, was produced in the Douglas plant in Tulsa, Oklahoma. This version was equipped with an increased ammunition supply. Over 2,400 of these were built. A few of them were shipped to the Royal Navy for evaluation. In addition to American service, the SBD saw combat against the Japanese Army and Navy with No. 25 Squadron of the Royal New Zealand Air Force—but the RNZAF soon replaced them with the larger, faster and land-based Vought F4U Corsairs. Some SBDs were flown by the Free French Air Force against the German Heer and Luftwaffe. SBDs were sold to Mexico; the final version, the SBD-6, had more improvements, but its production ended during the summer of 1944. The U. S. Army Air Force had its own version of the SBD, called the A-24 Banshee, it lacked the tail hook used for carrier landings, a pneumatic tire replaced the solid tail wheel. First assigned to the 27th Bombardment Group at Hunter Field, Georgia, A-24s flew in the Louisiana maneuvers of September 1941. There were three versions of the Banshee flown by the army to a minor degree in the early stages of the war.
The USAAF used 948 of the 5,937 Dauntlesses built. U. S. Navy and Marine Corps SBDs saw their first action at Pearl Harbor, when most of the Marine Corps SBDs of Marine Scout Bombing Squadron 232 were destroyed on the ground at Ewa Mooring Mast Field. Most U. S. Navy SBDs operating with their aircraft carriers, which did not operate in close cooperation with the rest of the fleet. Several Navy SBDs were flying to Pearl Harbor from carriers on the morning of December 7, engaged with Japanese aircraft. Most Navy SBDs at Pearl Harbor, like their Marine Corps counterparts, were destroyed on the ground. On 10 December 1941, SBDs from USS Enterprise sank the Japanese submarine I-70. In February–March 1942, SBDs from the carriers USS Lexington, USS Yorktown, Enterprise took part in various raids on Japanese installations in the Gilbert Islands, the Marshall Islands, New Guinea, Wake Island, Marcus Island; the first major use of the SBD in combat was at the Battle of the Coral Sea where SBDs and TBD Devastators sank the Japanese light aircraft carrier Shōhō and damaged the Japanese fleet carrier Shōkaku.
SBDs were used for anti-torpedo combat air patrols and these scored several victories against Japanese aircraft trying to attack Lexington and Yorktown. Their heavy gun armament with two forward-firing.50 in M2 Browning machine guns and either one or two rear flexible-mount.30 in AN/M2 machine guns was effective against the built Japanese fighters, many pilots and gunners took aggressive attitudes to the fighters that attacked them. SBD pilot Stanley "Swede" Vejtasa was attacked by three A6M2 Zero fighters; the SBD's most important contribution to the American war effort came during the Battle of Midway in early June 1942. Four squadrons of Navy SBD dive bombers attacked and sank or fatally damaged all four Japanese fleet carriers present, disabling three of them in the span of just six minutes and in the day, Hiryū, they caught two straggling heavy cruisers of the Midway bombardment group of four damaging them, with Mikuma sinking. At the Battle of Midway, Marine Corps SBDs were not as effective.
One squadron, VMSB-241, flying from Midway Atoll, was not trained in t