Soil erosion is the displacement of the upper layer of soil, one form of soil degradation. This natural process is caused by the dynamic activity of erosive agents, that is, ice, air, plants and humans. In accordance with these agents, erosion is sometimes divided into water erosion, glacial erosion, snow erosion, wind erosion, zoogenic erosion, anthropogenic erosion. Soil erosion may be a slow process that continues unnoticed, or it may occur at an alarming rate causing a serious loss of topsoil; the loss of soil from farmland may be reflected in reduced crop production potential, lower surface water quality and damaged drainage networks. Human activities have increased by 10 -- 40 times the rate. Excessive erosion causes both "on-site" and "off-site" problems. On-site impacts include decreases in agricultural productivity and ecological collapse, both because of loss of the nutrient-rich upper soil layers. In some cases, the eventual end result is desertification. Off-site effects include sedimentation of waterways and eutrophication of water bodies, as well as sediment-related damage to roads and houses.
Water and wind erosion are the two primary causes of land degradation. Intensive agriculture, roads, anthropogenic climate change and urban sprawl are amongst the most significant human activities in regard to their effect on stimulating erosion. However, there are many prevention and remediation practices that can curtail or limit erosion of vulnerable soils. Rainfall, the surface runoff which may result from rainfall, produces four main types of soil erosion: splash erosion, sheet erosion, rill erosion, gully erosion. Splash erosion is seen as the first and least severe stage in the soil erosion process, followed by sheet erosion rill erosion and gully erosion. In splash erosion, the impact of a falling raindrop creates a small crater in the soil, ejecting soil particles; the distance these soil particles travel can be as much as 0.6 m vertically and 1.5 m horizontally on level ground. If the soil is saturated, or if the rainfall rate is greater than the rate at which water can infiltrate into the soil, surface runoff occurs.
If the runoff has sufficient flow energy, it will transport loosened soil particles down the slope. Sheet erosion is the transport of loosened soil particles by overland flow. Rill erosion refers to the development of small, ephemeral concentrated flow paths which function as both sediment source and sediment delivery systems for erosion on hillslopes. Where water erosion rates on disturbed upland areas are greatest, rills are active. Flow depths in rills are of the order of a few centimeters or less and along-channel slopes may be quite steep; this means that rills exhibit hydraulic physics different from water flowing through the deeper, wider channels of streams and rivers. Gully erosion occurs when runoff water accumulates and flows in narrow channels during or after heavy rains or melting snow, removing soil to a considerable depth. Valley or stream erosion occurs with continued water flow along a linear feature; the erosion is both downward, deepening the valley, headward, extending the valley into the hillside, creating head cuts and steep banks.
In the earliest stage of stream erosion, the erosive activity is dominantly vertical, the valleys have a typical V cross-section and the stream gradient is steep. When some base level is reached, the erosive activity switches to lateral erosion, which widens the valley floor and creates a narrow floodplain; the stream gradient becomes nearly flat, lateral deposition of sediments becomes important as the stream meanders across the valley floor. In all stages of stream erosion, by far the most erosion occurs during times of flood, when more and faster-moving water is available to carry a larger sediment load. In such processes, it is not the water alone that erodes: suspended abrasive particles and boulders can act erosively as they traverse a surface, in a process known as traction. Bank erosion is the wearing away of the banks of a river; this is distinguished from changes on the bed of the watercourse, referred to as scour. Erosion and changes in the form of river banks may be measured by inserting metal rods into the bank and marking the position of the bank surface along the rods at different times.
Thermal erosion is the result of weakening permafrost due to moving water. It can occur both at the coast. Rapid river channel migration observed in the Lena River of Siberia is due to thermal erosion, as these portions of the banks are composed of permafrost-cemented non-cohesive materials. Much of this erosion occurs. Thermal erosion affects the Arctic coast, where wave action and near-shore temperatures combine to undercut permafrost bluffs along the shoreline and cause them to fail. Annual erosion rates along a 100-kilometre segment of the Beaufort Sea shoreline averaged 5.6 metres per year from 1955 to 2002. At high flows, kolks, or vortices are formed by large volumes of rushing water. Kolks cause extreme local erosion, plucking bedrock and creating pothole-type geographical features called Rock-cut basins. Examples can be seen in the flood regions result from glacial Lake Missoula, which created the channeled scablands in the Columbia Basin region of eastern W
A planimeter known as a platometer, is a measuring instrument used to determine the area of an arbitrary two-dimensional shape. There are several kinds of planimeters; the precise way in which they are constructed varies, with the main types of mechanical planimeter being polar and Prytz or "hatchet" planimeters. The Swiss mathematician Jakob Amsler-Laffon built the first modern planimeter in 1854, the concept having been pioneered by Johann Martin Hermann in 1814. Many developments followed Amsler's famous planimeter, including electronic versions; the Amsler type consists of a two-bar linkage. At the end of one link is a pointer, used to trace around the boundary of the shape to be measured; the other end of the linkage pivots on a weight that keeps it from moving. Near the junction of the two links is a measuring wheel of calibrated diameter, with a scale to show fine rotation, worm gearing for an auxiliary turns counter scale; as the area outline is traced, this wheel rolls on the surface of the drawing.
The operator sets the wheel, turns the counter to zero, traces the pointer around the perimeter of the shape. When the tracing is complete, the scales at the measuring wheel show the shape's area; when the planimeter's measuring wheel moves perpendicular to its axis, it rolls, this movement is recorded. When the measuring wheel moves parallel to its axis, the wheel skids without rolling, so this movement is ignored; that means the planimeter measures the distance that its measuring wheel travels, projected perpendicularly to the measuring wheel's axis of rotation. The area of the shape is proportional to the number of turns through which the measuring wheel rotates; the polar planimeter is restricted by design to measuring areas within limits determined by its size and geometry. However, the linear type has no restriction in one dimension, its wheels must not slip. Developments of the planimeter can establish the position of the first moment of area, the second moment of area; the images show the principles of a polar planimeter.
The pointer M at one end of the planimeter follows the contour C of the surface S to be measured. For the linear planimeter the movement of the "elbow" E is restricted to the y-axis. For the polar planimeter the "elbow" is connected to an arm with its other endpoint O at a fixed position. Connected to the arm ME is the measuring wheel with its axis of rotation parallel to ME. A movement of the arm ME can be decomposed into a movement perpendicular to ME, causing the wheel to rotate, a movement parallel to ME, causing the wheel to skid, with no contribution to its reading; the working of the linear planimeter may be explained by measuring the area of a rectangle ABCD. Moving with the pointer from A to B the arm EM moves through the yellow parallelogram, with area equal to PQ×EM; this area is equal to the area of the parallelogram A"ABB". The measuring wheel measures the distance PQ. Moving from C to D the arm EM moves through the green parallelogram, with area equal to the area of the rectangle D"DCC".
The measuring wheel now moves in the opposite direction. The movements along BC and DA are the same but opposite, so they cancel each other with no net effect on the reading of the wheel; the net result is the measuring of the difference of the yellow and green areas, the area of ABCD. The operation of a linear planimeter can be justified by applying Green's theorem onto the components of the vector field N, given by: N =, where b is the y-coordinate of the elbow E; this vector field is perpendicular to the measuring arm EM: E M → ⋅ N = x N x + N y = 0 and has a constant size, equal to the length m of the measuring arm: ‖ N ‖ = 2 + x 2 = m Then: ∮ C = ∬ S d x d y = ∬ S d x d
University of California, Los Angeles
The University of California, Los Angeles is a public research university in Los Angeles. It became the Southern Branch of the University of California in 1919, making it the third-oldest undergraduate campus of the 10-campus University of California system, it offers 337 graduate degree programs in a wide range of disciplines. UCLA enrolls about 31,000 undergraduate and 13,000 graduate students and had 119,000 applicants for Fall 2016, including transfer applicants, making the school the most applied-to of any American university; the university is organized into six undergraduate colleges, seven professional schools, four professional health science schools. The undergraduate colleges are the College of Science; as of 2017, 24 Nobel laureates, three Fields Medalists, five Turing Award winners, two Chief Scientists of the U. S. Air Force have been affiliated with UCLA as researchers, or alumni. Among the current faculty members, 55 have been elected to the National Academy of Sciences, 28 to the National Academy of Engineering, 39 to the Institute of Medicine, 124 to the American Academy of Arts and Sciences.
The university was elected to the Association of American Universities in 1974. UCLA is considered one of the country's Public Ivies, meaning that it is a public university thought to provide a quality of education comparable with that of the Ivy League. In 2018, US News & World Report named UCLA the best public university in the United States. UCLA student-athletes compete as the Bruins in the Pac-12 Conference; the Bruins have won 126 national championships, including 116 NCAA team championships, more than any other university except Stanford, who has won 117. UCLA student-athletes and staff won 251 Olympic medals: 126 gold, 65 silver, 60 bronze. UCLA student-athletes competed in every Olympics since 1920 with one exception and won a gold medal in every Olympics the U. S. participated in since 1932. In March 1881, the California State Legislature authorized the creation of a southern branch of the California State Normal School in downtown Los Angeles to train teachers for the growing population of Southern California.
The Los Angeles branch of the California State Normal School opened on August 29, 1882, on what is now the site of the Central Library of the Los Angeles Public Library system. The facility included an elementary school where teachers-in-training could practice their technique with children; that elementary school is related to the present day UCLA Lab School. In 1887, the branch campus became independent and changed its name to Los Angeles State Normal School. In 1914, the school moved to a new campus on Vermont Avenue in East Hollywood. In 1917, UC Regent Edward Augustus Dickson, the only regent representing the Southland at the time, Ernest Carroll Moore, Director of the Normal School, began to lobby the State Legislature to enable the school to become the second University of California campus, after UC Berkeley, they met resistance from UC Berkeley alumni, Northern California members of the state legislature, Benjamin Ide Wheeler, President of the University of California from 1899 to 1919, who were all vigorously opposed to the idea of a southern campus.
However, David Prescott Barrows, the new President of the University of California, did not share Wheeler's objections. On May 23, 1919, the Southern Californians' efforts were rewarded when Governor William D. Stephens signed Assembly Bill 626 into law, which transformed the Los Angeles Normal School into the Southern Branch of the University of California; the same legislation added the College of Letters and Science. The Southern Branch campus opened on September 15 of that year, offering two-year undergraduate programs to 250 Letters and Science students and 1,250 students in the Teachers College, under Moore's continued direction. Under University of California President William Wallace Campbell, enrollment at the Southern Branch expanded so that by the mid-1920s the institution was outgrowing the 25 acre Vermont Avenue location; the Regents searched for a new location and announced their selection of the so-called "Beverly Site"—just west of Beverly Hills—on March 21, 1925 edging out the panoramic hills of the still-empty Palos Verdes Peninsula.
After the athletic teams entered the Pacific Coast conference in 1926, the Southern Branch student council adopted the nickname "Bruins", a name offered by the student council at UC Berkeley. In 1927, the Regents renamed the Southern Branch the University of California at Los Angeles. In the same year, the state broke ground in Westwood on land sold for $1 million, less than one-third its value, by real estate developers Edwin and Harold Janss, for whom the Janss Steps are named; the campus in Westwood opened to students in 1929. The original four buildings were the College Library, Royce Hall, the Physics-Biology Building, the Chemistry Building, arrayed around a quadrangular courtyard on the 400 acre campus; the first undergraduate classes on the new campus were held in 1929 with 5,500 students. After lobbying by alumni, faculty and community leaders, UCLA was permitted to award the master's degree in 1933, the doctorate in 1936, against continued resistance from UC Berkeley. A timeline of the history can be found on its website, as well
University of Manchester
The University of Manchester is a public research university in Manchester, formed in 2004 by the merger of the University of Manchester Institute of Science and Technology and the Victoria University of Manchester. The University of Manchester is a red brick university, a product of the civic university movement of the late 19th century; the main campus is south of Manchester city centre on Oxford Road. In 2016/17, the university had 40,490 students and 10,400 staff, making it the second largest university in the UK, the largest single-site university; the university had a consolidated income of £1 billion in 2017–18, of which £298.7 million was from research grants and contracts. It has the fourth-largest endowment of any university in the UK, after the universities of Cambridge and Edinburgh, it is a member of the worldwide Universities Research Association, the Russell Group of British research universities and the N8 Group. For 2018–19, the University of Manchester was ranked 29th in the world and 6th in the UK by QS World University Rankings.
In 2017 it was ranked 38th in the world and 6th in the UK by Academic Ranking of World Universities, 55th in the world and 8th in the UK by Times Higher Education World University Rankings and 59th in the world by U. S. News and World Report. Manchester was ranked 15th in the UK amongst multi-faculty institutions for the quality of its research and 5th for its Research Power in the 2014 Research Excellence Framework; the university owns and operates major cultural assets such as the Manchester Museum, Whitworth Art Gallery, John Rylands Library and Jodrell Bank Observatory and its Grade I listed Lovell Telescope. The University of Manchester has 25 Nobel laureates among its past and present students and staff, the fourth-highest number of any single university in the United Kingdom. Four Nobel laureates are among its staff – more than any other British university; the University of Manchester traces its roots to the formation of the Mechanics' Institute in 1824, its heritage is linked to Manchester's pride in being the world's first industrial city.
The English chemist John Dalton, together with Manchester businessmen and industrialists, established the Mechanics' Institute to ensure that workers could learn the basic principles of science. John Owens, a textile merchant, left a bequest of £96,942 in 1846 to found a college to educate men on non-sectarian lines, his trustees established Owens College in 1851 in a house on the corner of Quay Street and Byrom Street, the home of the philanthropist Richard Cobden, subsequently housed Manchester County Court. The locomotive designer, Charles Beyer became a governor of the college and was the largest single donor to the college extension fund, which raised the money to move to a new site and construct the main building now known as the John Owens building, he campaigned and helped fund the engineering chair, the first applied science department in the north of England. He left the college the equivalent of £10 million in his will in 1876, at a time when it was in great financial difficulty.
Beyer funded the total cost of construction of the Beyer building to house the biology and geology departments. His will funded Engineering chairs and the Beyer Professor of Applied mathematics; the university has a rich German heritage. The Owens College Extension Movement based their plans after a tour of German universities and polytechnics. Manchester mill owner, Thomas Ashton, chairman of the extension movement had studied at Heidelberg University. Sir Henry Roscoe studied at Heidelberg under Robert Bunsen and they collaborated for many years on research projects. Roscoe promoted the German style of research led teaching that became the role model for the redbrick universities. Charles Beyer studied at Dresden Academy Polytechnic. There were many Germans on the staff, including Carl Schorlemmer, Britain's first chair in organic chemistry, Arthur Schuster, professor of Physics. There was a German chapel on the campus. In 1873 the college moved to new premises on Oxford Road, Chorlton-on-Medlock and from 1880 it was a constituent college of the federal Victoria University.
The university was established and granted a Royal Charter in 1880 becoming England's first civic university. By 1905, the institutions were active forces; the Municipal College of Technology, forerunner of UMIST, was the Victoria University of Manchester's Faculty of Technology while continuing in parallel as a technical college offering advanced courses of study. Although UMIST achieved independent university status in 1955, the universities continued to work together. However, in the late-20th century, formal connections between the university and UMIST diminished and in 1994 most of the remaining institutional ties were severed as new legislation allowed UMIST to become an autonomous university with powers to award its own degrees. A decade the development was reversed; the Victoria University of Manchester and the University of Manchester Institute of Science and Technology agreed to merge into a single institution in March 2003. Before the merger, Victoria University of Manchester and UMIST counted 23 Nobel Prize winners amongst their former staff and students, with two further Nobel laureates being subsequently added.
Manchester has traditionally been strong in the sciences. Notable scientists as
Glenn Research Center
NASA John H. Glenn Research Center at Lewis Field is a NASA center, located within the cities of Brook Park and Cleveland between Cleveland Hopkins International Airport and the Rocky River Reservation of Cleveland Metroparks, with a subsidiary facility in Sandusky, Ohio, its director is Janet L. Kavandi. Glenn Research Center is one of ten major NASA field centers, whose primary mission is to develop science and technology for use in aeronautics and space; as of May 2012, it employed about 1,650 civil servants and 1,850 support contractors located on or near its site. In 2010, the on-site NASA Visitors Center moved to the Great Lakes Science Center in the North Coast Harbor area of downtown Cleveland; the installation was established in 1942 as part of the National Advisory Committee for Aeronautics and was incorporated into the National Aeronautics and Space Administration as a laboratory for aircraft engine research. It was first named the Aircraft Engine Research Laboratory after funding was approved in June 1940.
It was renamed the Flight Propulsion Research Laboratory in 1947, the Lewis Flight Propulsion Laboratory in 1948, the NASA Lewis Research Center in 1958. On March 1, 1999, the center was renamed the NASA John H. Glenn Research Center at Lewis Field. John Glenn was an American fighter pilot and politician; as early as 1951, researchers at the LFPL were studying the combustion processes in liquid rocket engines. The 6,400-acre Plum Brook Field Station near Sandusky, Ohio is part of Glenn, it is located about 50 miles from the main campus. It specializes in large scale tests that would be hazardous on the main campus; as of 2015, the station consisted of five major facilities: B-2 Spacecraft Propulsion Research Facility: not functional Combined Effects Chamber: never used and unusable Cryogenic Components Laboratory: slated for demolition Hypersonic Test Facility Space Power FacilityThe Plum Brook Reactor was decontaminated and decommissioned under a 2008 cost-plus-fee contract valued at more than $33.5 million.
The B-2 Spacecraft Propulsion Research Facility is the world's only facility capable of testing full-scale, upper-stage launch vehicles and rocket engines under simulated high-altitude conditions. The Space Power Facility houses the world's largest space environment vacuum chamber. An icing tunnel is capable of simulating atmospheric icing condition to test the effect of ice accretion on aircraft wings and body as well as to test anti-icing systems for aircraft; the Zero Gravity Research Facility is a vertical vacuum chamber used for microgravity experiments. It was designated a National Historic Landmark in 1985; the facility uses vertical drop tests in a vacuum chamber to investigate the behavior of components, liquids and combustion in such circumstances. The facility consists of a concrete-lined shaft, 28 feet in diameter, that extends 510 feet below ground level. An aluminum vacuum chamber, 20 feet in diameter and 470 feet high, is contained within the concrete shaft; the pressure in this vacuum chamber is reduced to 13.3 newtons per square meter before use.
After the closing of the Japan Microgravity Centre, the NASA Zero-G facility is the largest microgravity facility in the world. Another, smaller drop tower remains in use; that tower has a free fall time of 2.2 seconds, the Dropping In Microgravity Environment program is conducted there. NASA Glenn does significant research and technology development on jet engines, producing designs that reduce energy consumption and noise; the chevrons it invented for noise reduction appear on many commercial jet engines today, including the Boeing 787 Dreamliner. The Glenn Research Center, along with its partners in industry, are credited with the following: The liquid hydrogen rocket engine, which Wernher von Braun credited as being the critical technology leading to the Apollo moon landing The Centaur upper stage rocket The gridded ion thruster, a high-efficiency engine for spaceflight. A Glenn-derived ion engine was used on the successful NASA probe Deep Space 1; the Electrical Power System for Space Station Freedom, except for minor modifications, is used on the International Space Station.
NASA Glenn's core competencies are: Air-breathing propulsion Communications technology and development Space propulsion and cryogenic fluids management Power, energy storage, conversion Materials and structures for extreme environments The Glenn Research Center is home to the Lewis' Educational and Research Collaborative Internship Program. It provides internships for high school teachers; the high school program is an eight-week internship for sophomores and juniors with interests in science, engineering, math, or professional administration. The college level is open to college students at all levels. Only residents of the Cleveland area are eligible for high school LERCIP, but college LERCIP is open to students nationwide. Interns work with their NASA mentors and are involved in the daily activities of the Center, they are expected to be available to work 40 hours a week for the duration of the internship. The LERCIP Teacher program is a 10-week internship for educators in STEM fields; the Dropping In Microgravity Environment is an annual contest held yearly by the center.
Teams of high school students write proposals for experiments to be performed in the Drop Tower. The winners travel to the Center, perform their experiments, submit a research report to NASA. After 2004, NASA had been shifting its focus towards space exploration as manda
Norway the Kingdom of Norway, is a Nordic country in Northern Europe whose territory comprises the western and northernmost portion of the Scandinavian Peninsula. The Antarctic Peter I Island and the sub-Antarctic Bouvet Island are dependent territories and thus not considered part of the kingdom. Norway lays claim to a section of Antarctica known as Queen Maud Land. Norway has a total area of 385,207 square kilometres and a population of 5,312,300; the country shares a long eastern border with Sweden. Norway is bordered by Finland and Russia to the north-east, the Skagerrak strait to the south, with Denmark on the other side. Norway has an extensive coastline, facing the Barents Sea. Harald V of the House of Glücksburg is the current King of Norway. Erna Solberg has been prime minister since 2013. A unitary sovereign state with a constitutional monarchy, Norway divides state power between the parliament, the cabinet and the supreme court, as determined by the 1814 constitution; the kingdom was established in 872 as a merger of a large number of petty kingdoms and has existed continuously for 1,147 years.
From 1537 to 1814, Norway was a part of the Kingdom of Denmark-Norway, from 1814 to 1905, it was in a personal union with the Kingdom of Sweden. Norway was neutral during the First World War. Norway remained neutral until April 1940 when the country was invaded and occupied by Germany until the end of Second World War. Norway has both administrative and political subdivisions on two levels: counties and municipalities; the Sámi people have a certain amount of self-determination and influence over traditional territories through the Sámi Parliament and the Finnmark Act. Norway maintains close ties with both the United States. Norway is a founding member of the United Nations, NATO, the European Free Trade Association, the Council of Europe, the Antarctic Treaty, the Nordic Council. Norway maintains the Nordic welfare model with universal health care and a comprehensive social security system, its values are rooted in egalitarian ideals; the Norwegian state has large ownership positions in key industrial sectors, having extensive reserves of petroleum, natural gas, lumber and fresh water.
The petroleum industry accounts for around a quarter of the country's gross domestic product. On a per-capita basis, Norway is the world's largest producer of oil and natural gas outside of the Middle East; the country has the fourth-highest per capita income in the world on the World IMF lists. On the CIA's GDP per capita list which includes autonomous territories and regions, Norway ranks as number eleven, it has the world's largest sovereign wealth fund, with a value of US$1 trillion. Norway has had the highest Human Development Index ranking in the world since 2009, a position held between 2001 and 2006, it had the highest inequality-adjusted ranking until 2018 when Iceland moved to the top of the list. Norway ranked first on the World Happiness Report for 2017 and ranks first on the OECD Better Life Index, the Index of Public Integrity, the Democracy Index. Norway has one of the lowest crime rates in the world. Norway has two official names: Norge in Noreg in Nynorsk; the English name Norway comes from the Old English word Norþweg mentioned in 880, meaning "northern way" or "way leading to the north", how the Anglo-Saxons referred to the coastline of Atlantic Norway similar to scientific consensus about the origin of the Norwegian language name.
The Anglo-Saxons of Britain referred to the kingdom of Norway in 880 as Norðmanna land. There is some disagreement about whether the native name of Norway had the same etymology as the English form. According to the traditional dominant view, the first component was norðr, a cognate of English north, so the full name was Norðr vegr, "the way northwards", referring to the sailing route along the Norwegian coast, contrasting with suðrvegar "southern way" for, austrvegr "eastern way" for the Baltic. In the translation of Orosius for Alfred, the name is Norðweg, while in younger Old English sources the ð is gone. In the 10th century many Norsemen settled in Northern France, according to the sagas, in the area, called Normandy from norðmann, although not a Norwegian possession. In France normanni or northmanni referred to people of Sweden or Denmark; until around 1800 inhabitants of Western Norway where referred to as nordmenn while inhabitants of Eastern Norway where referred to as austmenn. According to another theory, the first component was a word nór, meaning "narrow" or "northern", referring to the inner-archipelago sailing route through the land.
The interpretation as "northern", as reflected in the English and Latin forms of the name, would have been due to folk etymology. This latter view originated with philologist Niels Halvorsen Trønnes in 1847; the form Nore is still used in placenames such as the village of Nore and lake Norefjorden in Buskerud county, still has the same meaning. Among other arguments in favour of the theor
A fire-control system is a number of components working together a gun data computer, a director, radar, designed to assist a weapon system in targetting and hitting its target. It performs the same task as a human gunner firing a weapon, but attempts to do so faster and more accurately; the original fire-control systems were developed for ships. The early history of naval fire control was dominated by the engagement of targets within visual range. In fact, most naval engagements before 1800 were conducted at ranges of 20 to 50 yards. During the American Civil War, the famous engagement between the USS Monitor and the CSS Virginia was conducted at less than 100 yards range. Rapid technical improvements in the late 19th century increased the range at which gunfire was possible. Rifled guns of much larger size firing explosive shells of lighter relative weight so increased the range of the guns that the main problem became aiming them while the ship was moving on the waves; this problem was solved with the introduction of the gyroscope, which corrected this motion and provided sub-degree accuracies.
Guns were now free to grow to any size, surpassed 10 inches calibre by the turn of the century. These guns were capable of such great range that the primary limitation was seeing the target, leading to the use of high masts on ships. Another technical improvement was the introduction of the steam turbine which increased the performance of the ships. Earlier screw-powered capital ships were capable of 16 knots, but the first large turbine ships were capable of over 20 knots. Combined with the long range of the guns, this meant that the ships moved a considerable distance, several ship lengths, between the time the shells were fired and landed. One could no longer eyeball the aim with any hope of accuracy. Moreover, in naval engagements it is necessary to control the firing of several guns at once. Naval gun fire control involves three levels of complexity. Local control originated with primitive gun installations aimed by the individual gun crews. Director control aims all guns on the ship at a single target.
Coordinated gunfire from a formation of ships at a single target was a focus of battleship fleet operations. Corrections are made for surface wind velocity, firing ship roll and pitch, powder magazine temperature, drift of rifled projectiles, individual gun bore diameter adjusted for shot-to-shot enlargement, rate of change of range with additional modifications to the firing solution based upon the observation of preceding shots; the resulting directions, known as a firing solution, would be fed back out to the turrets for laying. If the rounds missed, an observer could work out how far they missed by and in which direction, this information could be fed back into the computer along with any changes in the rest of the information and another shot attempted. At first, the guns were aimed using the technique of artillery spotting, it involved firing a gun at the target, observing the projectile's point of impact, correcting the aim based on where the shell was observed to land, which became more and more difficult as the range of the gun increased.
Between the American Civil War and 1905, numerous small improvements, such as telescopic sights and optical rangefinders, were made in fire control. There were procedural improvements, like the use of plotting boards to manually predict the position of a ship during an engagement. Sophisticated mechanical calculators were employed for proper gun laying with various spotters and distance measures being sent to a central plotting station deep within the ship. There the fire direction teams fed in the location and direction of the ship and its target, as well as various adjustments for Coriolis effect, weather effects on the air, other adjustments. Around 1905, mechanical fire control aids began to become available, such as the Dreyer Table and Argo Clock, but these devices took a number of years to become deployed; these devices were early forms of rangekeepers. Arthur Pollen and Frederic Charles Dreyer independently developed the first such systems. Pollen began working on the problem after noting the poor accuracy of naval artillery at a gunnery practice near Malta in 1900.
Lord Kelvin regarded as Britain's leading scientist first proposed using an analogue computer to solve the equations which arise from the relative motion of the ships engaged in the battle and the time delay in the flight of the shell to calculate the required trajectory and therefore the direction and elevation of the guns. Pollen aimed to produce a combined mechanical computer and automatic plot of ranges and rates for use in centralised fire control. To obtain accurate data of the target's position and relative motion, Pollen developed a plotting unit to capture this data. To this he added a gyroscope to allow for the yaw of the firing ship. Like the plotter, the primitive gyroscope of the time required substantial development to provide continuous and reliable guidance. Although the trials in 1905 and 1906 were unsuccessful, they showed promise. Pollen was encouraged in his efforts by the rising figure of Admiral Jackie Fisher, Admiral Arthur Knyvet Wilson and the Director of Naval Ordnance and Torpedoes, John Jellicoe.
Pollen continued his work, with occasional tests carried out on Royal Navy warships. Meanwhile, a group led by Dreyer designed a similar system. Although both systems were ordered for new and existing ships of the Royal Navy, the Dreyer system found most favour with the Navy in its definitive Mar