1.
Toll point
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In the United Kingdom a toll point or toll island is a place on a canal where a fee was collected as boats carrying cargo passed. Generally this was at a lock or an artificially constricted part of the canal so that the boat had to pass within inches of the toll point unable to evade the toll. On canals where the fee was based on cargo weight it also put the boat in a convenient place to read the gauging mark height from the water line, the BCN retains several of these islands, for example at Winson Green Junction. The maximum tolls were set by the navigation and canal Acts. Some early Acts allowed fees to be set by local commissioners or Quarter Sessions, fees were set in pence per mile, or part. Sometimes empty boats were exempt, or free if returning loaded, fees depended on the type of cargo. Coal, stone and lime were the cheapest, then iron ore, then finished goods, with perishables, tolls might be refunded for long distance trips to encourage expansion of trade - drawbacks - particularly applied to the coal trade. Some exceptions were made to local land owners. The delivery of straw, manure or road building materials, as well as coal for the poor, or contribution to county rates may have freed the carrier of toll fees, in the 1790s toll fees were greatly reduced by Parliament to encourage canal use. In practice, competition kept tolls below the maximum, particularly after the arrival of the railways, another type of toll was the compensation toll, charged on a new canal joining an existing waterway, perhaps 5d. on all goods. Fees were paid by the boatman or by account, fraud was common, under declaration of the cargo, hiding valuable goods under cheaper cargo, or by bribery. Tolls lasted until nationalisation in 1948 but are paid by commercial carriers on commercial waterways. Pleasure boats pay British Waterways an annual licence fee based on the length of the craft, canals were set up as commercial enterprises. The fee for using the canals was dependent on the type of cargo, each boat had to have four gauging plates fitted to the hull at the corners of the boat - bow and stern at each side - indicating a measurement point and a boat serial number. These measurements were logged in toll-keepers tables and copies sent to every toll office within the trading range. At toll offices if a toll collector suspected an incorrect waybill the height of the four corners of the boat were checked with a gauging stick and that boats entry in the gauging table was used to determine the cargo weight. The toll fee was worked out from the weight and cargo type, the fitting and calibration of gauging plates was done at a gauging station or indexing station. The channels either side allowed two-way traffic and possibly the collection of tolls, the buildings and equipment were demolished in the 1940s
2.
River Brant
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The River Brant is a 14 miles long tributary of the River Witham that flows entirely in the county of Lincolnshire, in the east of England. In 1855 the River was described as follows, Brant, a tributary of the Witham in the part of the county of Lincoln. This small stream has its rise in several fine springs in the parish of Hough-on-the-Hill, the origin of the name is from the Old English, brant. Steep being a steeply sloping incline, the river flows past Brandon to which it gives its name, then reaches Stragglethorpe where it is joined by The Beck, which drains Fulbeck. Further north it reaches its confluence with the River Witham between the villages of Aubourn and South Hykeham
3.
Hydrology
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Hydrology is the scientific study of the movement, distribution, and quality of water on Earth and other planets, including the water cycle, water resources and environmental watershed sustainability. A practitioner of hydrology is a hydrologist, working within the fields of earth or environmental science, physical geography, geology or civil, Hydrology subdivides into surface water hydrology, groundwater hydrology, and marine hydrology. Domains of hydrology include hydrometeorology, surface hydrology, hydrogeology, drainage-basin management and water quality, oceanography and meteorology are not included because water is only one of many important aspects within those fields. Hydrological research can inform environmental engineering, policy and planning, the term hydrology comes from Greek, ὕδωρ, hýdōr, water, and λόγος, lógos, study. Chemical hydrology is the study of the characteristics of water. Ecohydrology is the study of interactions between organisms and the hydrologic cycle, hydrogeology is the study of the presence and movement of groundwater. Hydroinformatics is the adaptation of technology to hydrology and water resources applications. Hydrometeorology is the study of the transfer of water and energy between land and water surfaces and the lower atmosphere. Isotope hydrology is the study of the signatures of water. Surface hydrology is the study of processes that operate at or near Earths surface. Drainage basin management covers water-storage, in the form of reservoirs, water quality includes the chemistry of water in rivers and lakes, both of pollutants and natural solutes. Determining the water balance of a region, mitigating and predicting flood, landslide and drought risk. Real-time flood forecasting and flood warning, designing irrigation schemes and managing agricultural productivity. Part of the module in catastrophe modeling. Designing dams for water supply or hydroelectric power generation, designing sewers and urban drainage system. Analyzing the impacts of antecedent moisture on sanitary sewer systems, predicting geomorphologic changes, such as erosion or sedimentation. Assessing the impacts of natural and anthropogenic environmental change on water resources, assessing contaminant transport risk and establishing environmental policy guidelines. Hydrology has been a subject of investigation and engineering for millennia, for example, about 4000 BC the Nile was dammed to improve agricultural productivity of previously barren lands
4.
Environmental science
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Environmental science is an interdisciplinary academic field that integrates physical, biological and information sciences to the study of the environment, and the solution of environmental problems. Environmental science emerged from the fields of history and medicine during the Enlightenment. Today it provides an integrated, quantitative, and interdisciplinary approach to the study of environmental systems, related areas of study include environmental studies and environmental engineering. Environmental studies incorporates more of the sciences for understanding human relationships, perceptions. Environmental engineering focuses on design and technology for improving environmental quality in every aspect, Environmental issues almost always include an interaction of physical, chemical, and biological processes. Environmental scientists bring a systems approach to the analysis of environmental problems, key elements of an effective environmental scientist include the ability to relate space, and time relationships as well as quantitative analysis. Ecology could be considered a subset of science, which also could involve purely chemical or public health issues ecologists would be unlikely to study. In practice, there is overlap between the work of ecologists and other environmental scientists. Includes instruction in biology, chemistry, physics, geosciences, climatology, statistics, atmospheric sciences focus on the Earths atmosphere, with an emphasis upon its interrelation to other systems. Ecology is the study of the interactions between organisms and their environment, for example, an interdisciplinary analysis of an ecological system which is being impacted by one or more stressors might include several related environmental science fields. Environmental chemistry is the study of chemical alterations in the environment, principal areas of study include soil contamination and water pollution. The topics of analysis include chemical degradation in the environment, multi-phase transport of chemicals, as an example study, consider the case of a leaking solvent tank which has entered the habitat soil of an endangered species of amphibian. As a method to resolve or understand the extent of contamination and subsurface transport of solvent. Geosciences include environmental geology, environmental science, volcanic phenomena. In some classification systems this can also include hydrology, including oceanography, as an example study of soils erosion, calculations would be made of surface runoff by soil scientists. Fluvial geomorphologists would assist in examining sediment transport in overland flow, physicists would contribute by assessing the changes in light transmission in the receiving waters. Biologists would analyze subsequent impacts to aquatic flora and fauna from increases in water turbidity, in the U. S. the National Environmental Policy Act of 1969 set forth requirements for analysis of major projects in terms of specific environmental criteria. Numerous state laws have echoed these mandates, applying the principles to local-scale actions, the upshot has been an explosion of documentation and study of environmental consequences before the fact of development actions
5.
Surface water
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Surface water is water on the surface of the planet such as in a river, lake, wetland, or ocean. It can be contrasted with groundwater and atmospheric water, non-saline surface water is replenished by precipitation and by recruitment from ground-water. Surface and groundwater are two entities, so they must be regarded as such. However, there is an ever-increasing need for management of the two as they are part of a system that is paramount when the demand for water exceeds the available supply. Depletion of surface and ground water sources for public consumption is caused by over-pumping, aquifers near river systems that are over-pumped have been known to deplete surface water sources as well. Research supporting this has found in numerous water budgets for a multitude of cities. Response times for an aquifer are long, however, a total ban on ground water usage during water recessions would allow surface water to retain better levels required for sustainable aquatic life. By reducing ground water pumping, the water supplies will be able to maintain their levels, as they recharge from direct precipitation, surface runoff. Environmental persistent pharmaceutical pollutant Meltwater Optimum water content for tillage Applied Hydrogeology, Fourth Edition by C. W. Fetter
6.
Discharge (hydrology)
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In hydrology, discharge is the volume rate of water flow that is transported through a given cross-sectional area. It includes any suspended solids, dissolved chemicals, or biologic material in addition to the water itself, GH Dury and MJ Bradshaw are two hydrologists who devised the models showing the relationship between discharge and other variables in a river. The units that are used to express discharge include m³/s, ft³/s and/or acre-feet per day. For example, the discharge of the Rhine river in Europe is 2,200 cubic metres per second or 190,000,000 cubic metres per day. A commonly applied methodology for measuring, and estimating, the discharge of a river is based on a form of the continuity equation. In storm hydrology, an important consideration is the streams discharge hydrograph, the stream rises to a peak flow after each precipitation event, then falls in a slow recession. Because the peak flow also corresponds to the water level reached during the event. The amount of precipitation correlates to the volume of water that flows out of the river. The relationship between the discharge in the stream at a given cross-section and the level of the stream is described by a rating curve, average velocities and the cross-sectional area of the stream are measured for a given stream level. The velocity and the give the discharge for that level. After measurements are made for different levels, a rating table or rating curve may be developed. Once rated, the discharge in the stream may be determined by measuring the level, if a continuous level-recording device is located at a rated cross-section, the streams discharge may be continuously determined. Larger flows can transport more sediment and larger particles downstream than smaller flows due to their greater force, larger flows can also erode stream banks and damage public infrastructure
7.
Water quality
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Water quality refers to the chemical, physical, biological, and radiological characteristics of water. It is a measure of the condition of water relative to the requirements of one or more biotic species and it is most frequently used by reference to a set of standards against which compliance can be assessed. The most common used to assess water quality relate to health of ecosystems, safety of human contact. In the setting of standards, agencies make political and technical/scientific decisions about how the water will be used, in the case of natural water bodies, they also make some reasonable estimate of pristine conditions. Natural water bodies will vary in response to environmental conditions, Environmental scientists work to understand how these systems function, which in turn helps to identify the sources and fates of contaminants. Environmental lawyers and policymakers work to define legislation with the intention that water is maintained at a quality for its identified use. The vast majority of water on the Earth is neither potable nor toxic. This remains true when seawater in the oceans is not counted, another general perception of water quality is that of a simple property that tells whether water is polluted or not. In fact, water quality is a subject, in part because water is a complex medium intrinsically tied to the ecology of the Earth. Industrial and commercial activities are a cause of water pollution as are runoff from agricultural areas, urban runoff. The parameters for water quality are determined by the intended use, work in the area of water quality tends to be focused on water that is treated for human consumption, industrial use, or in the environment. Water quality depends on the geology and ecosystem, as well as human uses such as sewage dispersion, industrial pollution, use of water bodies as a heat sink. The United States Environmental Protection Agency limits the amounts of contaminants in tap water provided by US public water systems. The U. S. Food and Drug Administration regulations establish limits for contaminants in bottled water that must provide the protection for public health. Drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some contaminants, the presence of these contaminants does not necessarily indicate that the water poses a health risk. Water drawn directly from a stream, lake, or aquifer, dissolved minerals may affect suitability of water for a range of industrial and domestic purposes. Hard water may be softened to remove these ions, the softening process often substitutes sodium cations. Hard water may be preferable to soft water for consumption, since health problems have been associated with excess sodium
8.
Topographic map
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Traditional definitions require a topographic map to show both natural and man-made features. A topographic map is published as a map series, made up of two or more map sheets that combine to form the whole map. A contour line is a line connecting places of equal elevation, however, in the vernacular and day to day world, the representation of relief is popularly held to define the genre, such that even small-scale maps showing relief are commonly called topographic. The study or discipline of topography is a broader field of study. Topographic maps are based on topographical surveys, performed at large scales, these surveys are called topographical in the old sense of topography, showing a variety of elevations and landforms. This is in contrast to older cadastral surveys, which primarily show property, the first multi-sheet topographic map series of an entire country, the Carte géométrique de la France, was completed in 1789. Topographic surveys were prepared by the military to assist in planning for battle, as such, elevation information was of vital importance. As they evolved, topographic map series became a resource in modern nations in planning infrastructure. Excluding borders, each sheet was 44 cm high and up to 66 cm wide, although the project eventually foundered, it left an indexing system that remains in use. TIGER was developed in the 1980s and used in the 1990, digital elevation models were also compiled, initially from topographic maps and stereographic interpretation of aerial photographs and then from satellite photography and radar data. Since all these were government projects funded with taxes and not classified for security reasons. Initial applications were mostly professionalized forms such as innovative surveying instruments, by the mid-1990s, increasingly user-friendly resources such as online mapping in two and three dimensions, integration of GPS with mobile phones and automotive navigation systems appeared. As of 2011, the future of standardized, centrally printed topographical maps is left somewhat in doubt, the various features shown on the map are represented by conventional signs or symbols. For example, colors can be used to indicate a classification of roads and these signs are usually explained in the margin of the map, or on a separately published characteristic sheet. Topographic maps are commonly called contour maps or topo maps. In the United States, where the national series is organized by a strict 7. 5-minute grid. Topographic maps conventionally show topography, or land contours, by means of contour lines, contour lines are curves that connect contiguous points of the same altitude. In other words, every point on the line of 100 m elevation is 100 m above mean sea level
9.
Telemetry
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Telemetry is an automated communications process by which measurements and other data are collected at remote or inaccessible points and transmitted to receiving equipment for monitoring. The word is derived from Greek roots, tele = remote, systems that need external instructions and data to operate require the counterpart of telemetry, telecommand. Many modern telemetry systems take advantage of the low cost and ubiquity of GSM networks by using SMS to receive, a telemeter is a device used to remotely measure any quantity. It consists of a sensor, a path, and a display, recording. Telemeters are the devices used in telemetry. Electronic devices are used in telemetry and can be wireless or hard-wired. Other technologies are possible, such as mechanical, hydraulic. Telemetry may be commutated to allow the transmission of data streams in a fixed frame. Telemetering information over wire had its origins in the 19th century, One of the first data-transmission circuits was developed in 1845 between the Russian Tsars Winter Palace and army headquarters. In 1874, French engineers built a system of weather and snow-depth sensors on Mont Blanc that transmitted real-time information to Paris, in 1901 the American inventor C. Michalke patented the selsyn, a circuit for sending synchronized rotation information over a distance, in 1906 a set of seismic stations were built with telemetering to the Pulkovo Observatory in Russia. In 1912, Commonwealth Edison developed a system of telemetry to monitor electrical loads on its power grid, the Panama Canal used extensive telemetry systems to monitor locks and water levels. Wireless telemetry made early appearances in the radiosonde, developed concurrently in 1930 by Robert Bureau in France, mochanovs system modulated temperature and pressure measurements by converting them to wireless Morse code. In the US and the USSR, the Messina system was replaced with better systems. Early Soviet missile and space telemetry systems which were developed in the late 1940s used either pulse-position modulation or pulse-duration modulation, in the United States, early work employed similar systems, but were later replaced by pulse-code modulation. Later Soviet interplanetary probes used redundant radio systems, transmitting telemetry by PCM on a decimeter band, telemetry has been used by weather balloons for transmitting meteorological data since 1920. Telemetry is used to transmit drilling mechanics and formation evaluation information uphole, in real time and these services are known as Measurement while drilling and Logging while drilling. Information acquired thousands of feet below ground, while drilling, is sent through the hole to the surface sensors
10.
Data logger
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A data logger is an electronic device that records data over time or in relation to location either with a built in instrument or sensor or via external instruments and sensors. Increasingly, but not entirely, they are based on a digital processor and they generally are small, battery powered, portable, and equipped with a microprocessor, internal memory for data storage, and sensors. Data loggers vary between general purpose types for a range of measurement applications to specific devices for measuring in one environment or application type only. It is common for general purpose types to be programmable, however, electronic data loggers have replaced chart recorders in many applications. One of the benefits of using data loggers is the ability to automatically collect data on a 24-hour basis. Upon activation, data loggers are typically deployed and left unattended to measure and this allows for a comprehensive, accurate picture of the environmental conditions being monitored, such as air temperature and relative humidity. The cost of data loggers has been declining over the years as technology improves, simple single channel data loggers cost as little as $25. More complicated loggers may costs hundreds or thousands of dollars, standardisation of protocols and data formats has been a problem but is now growing in the industry and XML, JSON, and YAML are increasingly being adopted for data exchange. The development of the Semantic Web and the Internet of Things is likely to accelerate this present trend, several protocols have been standardised including a smart protocol, SDI-12, that allows some instrumentation to be connected to a variety of data loggers. The use of this standard has not gained much acceptance outside the environmental industry, SDI-12 also supports multi drop instruments. Some datalogging companies are now supporting the MODBUS standard. This has been used traditionally in the control area. Another multi drop protocol which is now starting to become widely used is based upon CAN Bus. Some data loggers use a flexible scripting environment to adapt themselves to various non-standard protocols, the terms data logging and data acquisition are often used interchangeably. However, in a context they are quite different. A data logger is a data system, but a data acquisition system is not necessarily a data logger. Data loggers typically have slower sample rates, a maximum sample rate of 1 Hz may be considered to be very fast for a data logger, yet very slow for a typical data acquisition system. Data loggers are implicitly stand-alone devices, while typical data acquisition system must remain tethered to a computer to acquire data and this stand-alone aspect of data loggers implies on-board memory that is used to store acquired data
11.
Carnation, Washington
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Carnation is a city in King County, Washington, United States. The population was 1,786 at the 2010 census, settled in 1865, Carnation was officially incorporated on December 30,1912, as Tolt. The name was changed to Carnation in 1917, back to Tolt on May 3,1928, the name Carnation was chosen to honor a nearby research farm operated by the Carnation Milk Products Company. Carnation is located at 47°38′54″N 121°54′31″W, according to the United States Census Bureau, the city has a total area of 1.18 square miles, of which,1.16 square miles is land and 0.02 square miles is water. The city is located on the east bank of the Snoqualmie River just north of where the Tolt River joins in, Camlann Medieval Village, a living history museum of a medieval English village, is located approximately four miles north of Carnation. Founded in the early 1980s, Camlann is devoted to teaching and entertaining schools, clubs, families, as of the census of 2010, there were 1,786 people,631 households, and 474 families residing in the city. The population density was 1,539.7 inhabitants per square mile, there were 665 housing units at an average density of 573.3 per square mile. The racial makeup of the city was 85. 8% White,0. 9% African American,1. 0% Native American,3. 1% Asian,0. 1% Pacific Islander,7. 1% from other races, and 2. 1% from two or more races. Hispanic or Latino of any race were 12. 7% of the population,19. 0% of all households were made up of individuals and 6. 9% had someone living alone who was 65 years of age or older. The average household size was 2.83 and the family size was 3.24. The median age in the city was 34.9 years. 30. 1% of residents were under the age of 18,6. 8% were between the ages of 18 and 24,29. 4% were from 25 to 44,27. 7% were from 45 to 64, and 6% were 65 years of age or older. The gender makeup of the city was 49. 8% male and 50. 2% female, Carnation has a high rate of home ownership for King County,73. 31% of the homes in Carnation are occupied by people who own them. This rate is higher than nearby cities like Redmond, Bellevue. As of the census of 2000, there were 1,893 people,636 households, the population density was 1,728.4 people per square mile. There were 650 housing units at a density of 593.5 per square mile. The racial makeup of the city was 91. 76% White,1. 32% Native American,3. 59% Asian,0. 16% Pacific Islander,1. 80% from other races, hispanic or Latino of any race were 3. 91% of the population. 17. 5% of all households were made up of individuals and 7. 2% had someone living alone who was 65 years of age or older, the average household size was 2.98 and the average family size was 3.40
12.
Sensor
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A sensor is always used with other electronics, whether as simple as a light or as complex as a computer. Moreover, analog sensors such as potentiometers and force-sensing resistors are still widely used, applications include manufacturing and machinery, airplanes and aerospace, cars, medicine, robotics and many other aspects of our day-to-day life. A sensors sensitivity indicates how much the output changes when the input quantity being measured changes. For instance, if the mercury in a thermometer moves 1 cm when the changes by 1 °C. Some sensors can also affect what they measure, for instance, Sensors are usually designed to have a small effect on what is measured, making the sensor smaller often improves this and may introduce other advantages. Technological progress allows more and more sensors to be manufactured on a scale as microsensors using MEMS technology. In most cases, a microsensor reaches a higher speed. Most sensors have a transfer function. The sensitivity is defined as the ratio between the output signal and measured property. For example, if a sensor measures temperature and has a voltage output, the sensitivity is the slope of the transfer function. Converting the sensors electrical output to the measured units requires dividing the output by the slope. In addition, an offset is added or subtracted. For example -40 must be added to the output if 0 V output corresponds to -40 C input, for an analog sensor signal to be processed, or used in digital equipment, it needs to be converted to a digital signal, using an analog-to-digital converter. The full scale range defines the maximum and minimum values of the measured property, the sensitivity may in practice differ from the value specified. This is called a sensitivity error and this is an error in the slope of a linear transfer function. If the output differs from the correct value by a constant. This is an error in the y-intercept of a transfer function. Nonlinearity is deviation of a transfer function from a straight line transfer function
13.
Hydrologist
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Hydrology is the scientific study of the movement, distribution, and quality of water on Earth and other planets, including the water cycle, water resources and environmental watershed sustainability. A practitioner of hydrology is a hydrologist, working within the fields of earth or environmental science, physical geography, geology or civil, Hydrology subdivides into surface water hydrology, groundwater hydrology, and marine hydrology. Domains of hydrology include hydrometeorology, surface hydrology, hydrogeology, drainage-basin management and water quality, oceanography and meteorology are not included because water is only one of many important aspects within those fields. Hydrological research can inform environmental engineering, policy and planning, the term hydrology comes from Greek, ὕδωρ, hýdōr, water, and λόγος, lógos, study. Chemical hydrology is the study of the characteristics of water. Ecohydrology is the study of interactions between organisms and the hydrologic cycle, hydrogeology is the study of the presence and movement of groundwater. Hydroinformatics is the adaptation of technology to hydrology and water resources applications. Hydrometeorology is the study of the transfer of water and energy between land and water surfaces and the lower atmosphere. Isotope hydrology is the study of the signatures of water. Surface hydrology is the study of processes that operate at or near Earths surface. Drainage basin management covers water-storage, in the form of reservoirs, water quality includes the chemistry of water in rivers and lakes, both of pollutants and natural solutes. Determining the water balance of a region, mitigating and predicting flood, landslide and drought risk. Real-time flood forecasting and flood warning, designing irrigation schemes and managing agricultural productivity. Part of the module in catastrophe modeling. Designing dams for water supply or hydroelectric power generation, designing sewers and urban drainage system. Analyzing the impacts of antecedent moisture on sanitary sewer systems, predicting geomorphologic changes, such as erosion or sedimentation. Assessing the impacts of natural and anthropogenic environmental change on water resources, assessing contaminant transport risk and establishing environmental policy guidelines. Hydrology has been a subject of investigation and engineering for millennia, for example, about 4000 BC the Nile was dammed to improve agricultural productivity of previously barren lands
14.
United States Geological Survey
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The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its resources. The organization has four science disciplines, concerning biology, geography, geology. The USGS is a research organization with no regulatory responsibility. The USGS is a bureau of the United States Department of the Interior, the USGS employs approximately 8,670 people and is headquartered in Reston, Virginia. The USGS also has major offices near Lakewood, Colorado, at the Denver Federal Center, the current motto of the USGS, in use since August 1997, is science for a changing world. The agencys previous slogan, adopted on the occasion of its anniversary, was Earth Science in the Public Service. Prompted by a report from the National Academy of Sciences, the USGS was created, by a last-minute amendment and it was charged with the classification of the public lands, and examination of the geological structure, mineral resources, and products of the national domain. This task was driven by the need to inventory the vast lands added to the United States by the Louisiana Purchase in 1803, the legislation also provided that the Hayden, Powell, and Wheeler surveys be discontinued as of June 30,1879. Clarence King, the first director of USGS, assembled the new organization from disparate regional survey agencies, after a short tenure, King was succeeded in the directors chair by John Wesley Powell. Administratively, it is divided into a Headquarters unit and six Regional Units, Other specific programs include, Earthquake Hazards Program monitors earthquake activity worldwide. The National Earthquake Information Center in Golden, Colorado on the campus of the Colorado School of Mines detects the location, the USGS also runs or supports several regional monitoring networks in the United States under the umbrella of the Advanced National Seismic System. The USGS informs authorities, emergency responders, the media, and it also maintains long-term archives of earthquake data for scientific and engineering research. It also conducts and supports research on long-term seismic hazards, USGS has released the UCERF California earthquake forecast. The USGS National Geomagnetism Program monitors the magnetic field at magnetic observatories and distributes magnetometer data in real time, the USGS operates the streamgaging network for the United States, with over 7400 streamgages. Real-time streamflow data are available online, since 1962, the Astrogeology Research Program has been involved in global, lunar, and planetary exploration and mapping. USGS operates a number of related programs, notably the National Streamflow Information Program. USGS Water data is available from their National Water Information System database
15.
McMurdo Dry Valleys
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The McMurdo Dry Valleys are a row of snow-free valleys in Antarctica located within Victoria Land west of McMurdo Sound. The Dry Valleys experience extremely low humidity and surrounding mountains prevent the flow of ice from nearby glaciers, the rocks here are granites and gneisses, and glacial tills dot this bedrock landscape, with loose gravel covering the ground. The region is one of the worlds most extreme deserts, and includes many features including Lake Vida, a lake, and the Onyx River. The Dry Valleys are so named because of their extremely low humidity and they are also dry because, in this location, the mountains are sufficiently high that they block seaward flowing ice from the East Antarctic ice sheet from reaching the Ross Sea. At 4,800 square kilometres, the valleys constitute around 0. 03% of the continent, the valley floors are covered with loose gravel, in which ice wedge polygonal patterned ground may be observed. The unique conditions in the Dry Valleys are caused, in part, by katabatic winds, the winds can reach speeds of 320 kilometres per hour, heating as they descend, and evaporating all water, ice and snow. The valleys cut through the Beacon Supergroup, as well as older granites and gneisses of the Ross Orogeny, deposited directly from ice, tills dot this bedrock landscape. These are relatively thin and patchy, and differ markedly from the extensive, endolithic photosynthetic bacteria have been found living in the Dry Valleys, sheltered from the dry air in the relatively moist interior of rocks. Summer meltwater from the glaciers provides the source of soil nutrients. Scientists consider the Dry Valleys perhaps the closest of any terrestrial environment to the planet Mars, anaerobic bacteria whose metabolism is based on iron and sulfur live in sub-freezing temperatures under the Taylor Glacier. It was previously thought that the algae was staining red the ice emerging at Blood Falls and they found no living organisms in the permafrost, the first location on the planet visited by humans with no active microbial life. Part of the Valleys was designated a protected area in 2004. Alatna Valley is the northernmost, north of Benson Glacier, the most saline of all is small Don Juan Pond. Virtual Tour of the Dry Valleys A long-term ecological research group is working in the area, pictures from the Dry Valleys Satellite images
16.
Antarctica
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It contains the geographic South Pole and is situated in the Antarctic region of the Southern Hemisphere, almost entirely south of the Antarctic Circle, and is surrounded by the Southern Ocean. At 14,000,000 square kilometres, it is the fifth-largest continent, for comparison, Antarctica is nearly twice the size of Australia. About 98% of Antarctica is covered by ice that averages 1.9 km in thickness, Antarctica, on average, is the coldest, driest, and windiest continent, and has the highest average elevation of all the continents. Antarctica is a desert, with precipitation of only 200 mm along the coast. The temperature in Antarctica has reached −89.2 °C, though the average for the quarter is −63 °C. Anywhere from 1,000 to 5,000 people reside throughout the year at the research stations scattered across the continent. Organisms native to Antarctica include many types of algae, bacteria, fungi, plants, protista, vegetation, where it occurs, is tundra. The continent, however, remained neglected for the rest of the 19th century because of its hostile environment, lack of easily accessible resources. In 1895, the first confirmed landing was conducted by a team of Norwegians, Antarctica is a de facto condominium, governed by parties to the Antarctic Treaty System that have consulting status. Twelve countries signed the Antarctic Treaty in 1959, and thirty-eight have signed it since then, the treaty prohibits military activities and mineral mining, prohibits nuclear explosions and nuclear waste disposal, supports scientific research, and protects the continents ecozone. Ongoing experiments are conducted by more than 4,000 scientists from many nations, the name Antarctica is the romanised version of the Greek compound word ἀνταρκτική, feminine of ἀνταρκτικός, meaning opposite to the Arctic, opposite to the north. Aristotle wrote in his book Meteorology about an Antarctic region in c.350 B. C, marinus of Tyre reportedly used the name in his unpreserved world map from the 2nd century A. D. Before acquiring its present geographical connotations, the term was used for locations that could be defined as opposite to the north. For example, the short-lived French colony established in Brazil in the 16th century was called France Antarctique, the first formal use of the name Antarctica as a continental name in the 1890s is attributed to the Scottish cartographer John George Bartholomew. Antarctica has no population and there is no evidence that it was seen by humans until the 19th century. Explorer Matthew Flinders, in particular, has credited with popularising the transfer of the name Terra Australis to Australia. Cook came within about 120 km of the Antarctic coast before retreating in the face of ice in January 1773. The first confirmed sighting of Antarctica can be narrowed down to the crews of ships captained by three individuals, according to various organisations, ships captained by three men sighted Antarctica or its ice shelf in 1820, von Bellingshausen, Edward Bransfield, and Nathaniel Palmer
17.
Cross section (geometry)
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In geometry and science, a cross section is the intersection of a body in three-dimensional space with a plane, or the analog in higher-dimensional space. Cutting an object into slices creates many parallel cross sections, conic sections – circles, ellipses, parabolas, and hyperbolas – are formed by cross-sections of a cone at various different angles, as seen in the diagram at left. Any planar cross-section passing through the center of an ellipsoid forms an ellipse on its surface, a cross-section of a cylinder is a circle if the cross-section is parallel to the cylinders base, or an ellipse with non-zero eccentricity if it is neither parallel nor perpendicular to the base. If the cross-section is perpendicular to the base it consists of two line segments unless it is just tangent to the cylinder, in which case it is a single line segment. A cross section of a polyhedron is a polygon, if instead the cross section is taken for a fixed value of the density, the result is an iso-density contour. For the normal distribution, these contours are ellipses, a cross section can be used to visualize the partial derivative of a function with respect to one of its arguments, as shown at left. In economics, a function f specifies the output that can be produced by various quantities x and y of inputs, typically labor. The production function of a firm or a society can be plotted in three-dimensional space, also in economics, a cardinal or ordinal utility function u gives the degree of satisfaction of a consumer obtained by consuming quantities w and v of two goods. Cross sections are used in anatomy to illustrate the inner structure of an organ. A cross section of a trunk, as shown at left, reveals growth rings that can be used to find the age of the tree. Cavalieris principle states that solids with corresponding sections of equal areas have equal volumes. The cross-sectional area of an object when viewed from an angle is the total area of the orthographic projection of the object from that angle. For example, a cylinder of height h and radius r has A ′ = π r 2 when viewed along its central axis, a sphere of radius r has A ′ = π r 2 when viewed from any angle. For a convex body, each ray through the object from the viewers perspective crosses just two surfaces, descriptive geometry Exploded view drawing Graphical projection Plans
18.
Weir
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A weir /ˈwɪər/ is a barrier across the horizontal width of the river that alters the flow characteristics of the water and usually results in a change in the vertical height of the river level. There are many designs of weir, but commonly water flows freely over the top of the weir crest before cascading down to a lower level, Weirs are commonly used to prevent flooding, measure discharge and help render rivers navigable. In some locations the terms dam and weir are synonymous, a dam is usually specifically designed to impound water behind a wall, whilst a weir is designed to alter the river flow characteristics. A common distinction between dams and weirs is that flows over the top of a weir or underneath it for at least some of its length. Accordingly the crest of a spillway on a large dam may therefore be referred to as a weir. Weirs can vary in size both horizontally and vertically, with the smallest being only a few inches in height whilst the largest may be hundreds of metres long, some common weir purposes are outlined below. Weirs allow hydrologists and engineers a method of measuring the volumetric flow rate in small to medium-sized streams/rivers or in industrial discharge locations. Since the geometry of the top of the weir is known and all flows over the weir. However, this can only be achieved in locations where all water flows over the top of the weir crest, if these conditions are not met it can make flow measurement complicated, inaccurate or even impossible. The discharge calculation can be summarised as, Q = C L H n Where Q is flow rate of fluid C is the flow coefficent for the structure, Flow measurement weirs must be well maintained if they are to remain accurate. As weirs are a physical barrier they can impede the movement of fish and other animals up. This can have an effect of fish species that migrate as part of their breeding cycle. For example, weirs in the Great Lakes region have helped to prevent invasive Sea lamprey from colonising further upstream, mill ponds are created by a weir impounding water that then flows over the structure. The energy created by the change in height of the water can then be used to power waterwheels and power mill, Weirs are commonly used to control the flow rates of rivers during periods of high discharge. Sluice gates can be altered to increase or decrease the volume of flowing downstream. Weirs of this purpose are commonly found upstream of towns and villages, by slowing the rate at which water moves downstream even slightly a disproportionate effect can be had on the likelihood of flooding. On larger rivers a weir can also alter the characteristics of a river to the point that vessels are able to navigate areas previously inaccessible due to extreme currents or eddies. Many larger weirs will have built in that allow boats and river users to shoot the weir
19.
Mzingwane River
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The Mzingwane River, formerly known Umzingwane River as or Umzingwani River is a major left-bank tributary of the Limpopo River in Zimbabwe. The river contributes 9. 3% of the annual runoff of the Limpopo Basin. Major tributaries of the Mzingwane River include the Insiza, Inyankuni, Ncema, Umchabezi, the lower Mzingwane River is a sand filled channel, with extensive alluvial aquifers in the river channel and below the alluvial plains. Estimated water resources potential of these aquifers ranges between 175,000 m3 and 5,430,0003 in the channels and between 80,000 m3 and 6,920,0003 in the plains. Currently, some of these aquifers are being used to water for domestic use, livestock watering and dip tanks, commercial irrigation. There are four bridges over the Mzingwane River, Bridge on main Bulawayo - Beitbridge road. There is also a rail bridge, Bridge on main Mbalabala - Masvingo road. Bridge on main Bulawayo - Beitbridge road at West Nicholson, downstream of confluence with Insiza River, there is also a rail bridge. Bertie Knott Bridge, on the road from Beitbridge to Shashe Irrigation Scheme, there are also a number of fords, including, Two fords upstream of West Nicholson on Silalabuhwa and Mosholomoshe roads. Doddieburn ford, downstream of West Nicholson, in addition to a number of small weirs, there are two major dams on the Mzingwane River, Mzingwane Dam, built in 1962, with a full supply capacity of 42 MCM. It is located near the source of the river and supplies water to the city of Bulawayo, zhovhe Dam, built in 1995, with a full supply capacity of 136 MCM. Currently, a project is underway to construct a pipeline from the upper Mtshabezi River to Mzingwane Dam
20.
Zimbabwe
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Zimbabwe, officially the Republic of Zimbabwe, is a landlocked country located in southern Africa, between the Zambezi and Limpopo Rivers. It is bordered by South Africa to the south, Botswana to the west and southwest, Zambia to the northwest, although it does not border Namibia, less than 200 metres of the Zambezi River separates it from that country. The capital and largest city is Harare, a country of roughly 13 million people, Zimbabwe has 16 official languages, with English, Shona, and Ndebele the most commonly used. Since the 11th century, present-day Zimbabwe has been the site of several organised states and kingdoms as well as a route for migration. The British South Africa Company of Cecil Rhodes first demarcated the present territory during the 1890s, in 1965, the conservative white minority government unilaterally declared independence as Rhodesia. Zimbabwe then rejoined the Commonwealth of Nations—which it withdrew from in 2003 and it is a member of the United Nations, the Southern African Development Community, the African Union, and the Common Market for Eastern and Southern Africa. Robert Mugabe became Prime Minister of Zimbabwe in 1980, when his ZANU-PF party won the following the end of white minority rule. Under Mugabes authoritarian regime, the security apparatus has dominated the country. Mugabe has maintained the revolutionary socialist rhetoric from the Cold War era, the name Zimbabwe stems from a Shona term for Great Zimbabwe, an ancient ruined city in the countrys south-east whose remains are now a protected site. Two different theories address the origin of the word, many sources hold that Zimbabwe derives from dzimba-dza-mabwe, translated from the Karanga dialect of Shona as large houses of stone. The Karanga-speaking Shona people live around Great Zimbabwe in the province of Masvingo. Zimbabwe was formerly known as Southern Rhodesia, Rhodesia, and Zimbabwe Rhodesia, a further alternative, put forward by nationalists in Matabeleland, had been Matopos, referring to the Matopos Hills to the south of Bulawayo. In a 2001 interview, black nationalist Edson Zvobgo recalled that Mawema mentioned the name during a rally, and it caught hold. The black nationalist factions subsequently used the name the during the Second Chimurenga campaigns against the Rhodesian government during the Rhodesian Bush War of 1964-1979, major factions in this camp included the Zimbabwe African National Union, and the Zimbabwe African Peoples Union. Proto-Shona-speaking societies first emerged in the middle Limpopo valley in the 9th century before moving on to the Zimbabwean highlands, the Zimbabwean plateau eventually became the centre of subsequent Shona states, beginning around the 10th century. Around the early 10th century, trade developed with Arab merchants on the Indian Ocean coast, the main archaeological site uses a unique dry stone architecture. The Kingdom of Mapungubwe was the first in a series of sophisticated trade states developed in Zimbabwe by the time of the first European explorers from Portugal and they traded in gold, ivory, and copper for cloth and glass. From about 1300 until 1600, Mapungubwe was eclipsed by the Kingdom of Zimbabwe and this Shona state further refined and expanded upon Mapungubwes stone architecture, which survives to this day at the ruins of the kingdoms capital of Great Zimbabwe
21.
Flume
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A flume is a human-made channel for water in the form of an open declined gravity chute whose walls are raised above the surrounding terrain, in contrast to a trench or ditch. Flumes are not to be confused with aqueducts, which are built to water, rather than transporting materials using flowing water as a flume does. Flumes route water from a dam or weir to a desired materiel collection location. Many flumes took the form of wooden troughs elevated on trestles, originating as a part of a mill race, they were later used in the transportation of logs in the logging industry, known as a log flume. They were also used in hydraulic mining and working placer deposits for gold, tin. The term flume comes from the Old French word flum, from the Latin flumen and it was formerly used for a stream, and particularly for the tail of a mill race. A diversionary flume is used to water from one body to another. Log flumes use the flow of water to cut logs and timber downhill, sometimes many miles. Some varieties of flumes are used in measuring water flow of a larger channel, acceleration is accomplished through a convergence of the sidewalls, a change in floor elevation, or a combination of the two. Flow measurement flumes typically consist of a section, a throat section. Not all sections, however, need to be present, in the case of the Cutthroat flume, the converging section directly joins the diverging section, resulting in a throat section of no length. Other flumes omit the diverging section, Flow measurement flumes can be installed in earthen channels, concrete canals, below ground chambers, or factory integrated into Packaged Metering Manholes. In some 19th-century canals, a flume diverted water around a lift lock from the level above to the level below the lock. In competitive swimming, specialized flumes with transparent sides are often employed by coaches to analyze a swimmers technique, the speed of the flow is variable to accommodate the full spectrum of swimming styles and ability. Water Measurement with Flumes and Weirs, Weirs and Flumes for Flow Measurement
22.
Parshall flume
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The Parshall flume, the most recognized and commonly used flume today, is a fixed hydraulic structure developed to measure surface waters and irrigation flow. It is currently used to measure flow rate in industrial discharges, municipal sewer lines. The Parshall flume accelerates flow through a contraction of both the parallel sidewalls and a drop in the floor at the flume throat, under free-flow conditions the depth of water at specified location upstream of the flume throat can be converted to a rate of flow. Some states specify the use of Parshall flumes, by law, the design of the Parshall flume is standardized under ASTM D1941, ISO9826,1992, and JIS B7553-1993. The flumes are not patented and the tables are not copyright protected. Under laboratory conditions Parshall flumes can be expected to exhibit accuracies to within +/-2%, beginning in 1915, Dr. Ralph Parshall of the U. S. Soil Conservation Service altered the subcritical Venturi flume include a drop in elevation through the throat of the flume and this created a transition from subcritical flow conditions to supercritical flow conditions through the throat of the flume. Parshall was additionally honored as a Life Member of the ASCE, the width of the throat determines the flume size,22 standardized sizes have been developed, ranging from 1 in. to 50 ft. There are two conditions of flow that can occur in a Parshall Flume, free flow and submerged flow, when free flow conditions exist, the user only needs to collect one head measurement to determine the discharge. For submerged flow a secondary head measurement is required to determine the flume is submerged, the primary point of measurement is located in the inlet of the flume, two-thirds of the length of the converging section from the flume crest. The secondary point of measurement is located in the throat of the flume, a hydraulic jump occurs downstream of the flume for free flow conditions. As the flume becomes submerged, the hydraulic jump diminishes and ultimately disappears as the downstream conditions increasingly restrict the flow out of the flume, the sum of the kinetic and potential energy at a given point must be equal to the energy at any other point along the stream. The total energy or “head” must be equal, using the equations, we will solve for Q. In fact when looking at the tables, n has a value equal to or slightly greater than 1.5, while the value of C is larger than. It should be noted that the equations above will always underestimate actual flow since both the derived C and n values are lower than their respective chart values. For the Parshall Flume equation used to calculate the flow rate, likewise, in the energy conservation equation, y1 is needed. Free Flow – when there is no “back water” to restrict flow through a flume, only the upstream depth needs to be measured to calculate the flow rate. A free flow also induces a hydraulic jump downstream of the flume, submerged Flow – when the water surface downstream of the flume is high enough to restrict flow through a flume, submerged flume conditions exist
23.
Rotary encoder
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A rotary encoder, also called a shaft encoder, is an electro-mechanical device that converts the angular position or motion of a shaft or axle to an analog or digital code. There are two types, absolute and incremental. The output of absolute encoders indicates the current position of the shaft, the output of incremental encoders provides information about the motion of the shaft, which is typically further processed elsewhere into information such as speed, distance and position. Conductive, A series of circumferential copper tracks etched onto a PCB is used to encode the information, contact brushes sense the conductive areas. This form of encoder is now rarely seen except as an input in digital multimeters. Optical, This uses a light shining onto a photodiode through slits in a metal or glass disc and this is one of the most common technologies. Optical encoders are very sensitive to dust, on-Axis Magnetic, This technology typically uses a specially magnetized 2 pole neodymium magnet the same size as the motor shaft that typically requires a custom motor shaft be used. The accuracy is very bad and does not allow many resolution options and this technology does not typically offer UVW or Z pulse outputs. Due to the 2 pole magnet there is lots of jitter on the due to the internal interpolation. Off-Axis Magnetic, This technology typically employs the use of rubber bonded ferrite magnets attached to a metal hub and this offers flexibility in design and low cost for custom applications. Due to the flexibility in many off axis encoder chips they can be programmed to accept any number of pole widths so the chip can be placed in any position required for the application, Magnetic encoders operate in harsh environments where optical encoders would fail to work. An absolute encoder maintains position information when power is removed from the system, the position of the encoder is available immediately on applying power. An incremental encoder accurately records changes in position, but does not power up with a relation between encoder state and physical position. Devices controlled by incremental encoders may have to go home to a reference point to initialize the position measurement. A multi-turn absolute rotary encoder includes additional code wheels and gears, a high-resolution wheel measures the fractional rotation, and lower-resolution geared code wheels record the number of whole revolutions of the shaft. An absolute encoder has multiple code rings with various binary weightings which provide a data word representing the position of the encoder within one revolution. This type of encoder is often referred to as a parallel absolute encoder, an incremental encoder works differently by providing an A and a B pulse output that provide no usable count information in their own right. Rather, the counting is done in the external electronics, the point where the counting begins depends on the counter in the external electronics and not on the position of the encoder
24.
Potentiometer
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A potentiometer, informally a pot, is a three-terminal resistor with a sliding or rotating contact that forms an adjustable voltage divider. If only two terminals are used, one end and the wiper, it acts as a resistor or rheostat. The measuring instrument called a potentiometer is essentially a voltage divider used for measuring electric potential, potentiometers are commonly used to control electrical devices such as volume controls on audio equipment. Potentiometers operated by a mechanism can be used as transducers, for example. Potentiometers are rarely used to control significant power, since the power dissipated in the potentiometer would be comparable to the power in the controlled load. The resistive element can be flat or angled, each end of the resistive element is connected to a terminal on the case. The wiper is connected to a terminal, usually between the other two. On panel potentiometers, the wiper is usually the terminal of three. For single-turn potentiometers, this wiper typically travels just under one revolution around the contact, the only point of ingress for contamination is the narrow space between the shaft and the housing it rotates in. Another type is the slider potentiometer, which has a wiper which slides along a linear element instead of rotating. Contamination can potentially enter anywhere along the slot the slider moves in, making effective sealing more difficult, an advantage of the slider potentiometer is that the slider position gives a visual indication of its setting. The resistive element of inexpensive potentiometers is often made of graphite, other materials used include resistance wire, carbon particles in plastic, and a ceramic/metal mixture called cermet. Others are enclosed within the equipment and are intended to be adjusted to calibrate equipment during manufacture or repair and they are usually physically much smaller than user-accessible potentiometers, and may need to be operated by a screwdriver rather than having a knob. They are usually called preset potentiometers or trim pots, some presets are accessible by a small screwdriver poked through a hole in the case to allow servicing without dismantling. Multiturn potentiometers are also operated by rotating a shaft, but by several turns rather than less than a full turn, a string potentiometer is a multi-turn potentiometer operated by an attached reel of wire turning against a spring, enabling it to convert linear position to a variable resistance. User-accessible rotary potentiometers can be fitted with a switch which operates usually at the extreme of rotation. Multiple resistance elements can be ganged together with their contacts on the same shaft, for example. The relationship between position and resistance, known as the taper or law, is controlled by the manufacturer
25.
Ultrasonic transducer
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Ultrasonic transducers are divided into three broad categories, transmitters, receivers and transceivers. Transmitters convert electrical signals into ultrasound, receivers convert ultrasound into electrical signals, in a similar way to radar and sonar, ultrasonic transducers are used in systems which evaluate targets by interpreting the reflected signals. For example, by measuring the time between sending a signal and receiving an echo the distance of an object can be calculated, passive ultrasonic sensors are basically microphones that detect ultrasonic noise that is present under certain conditions. Ultrasonic probes and ultrasonic baths apply ultrasonic energy to agitate particles in a range of materials. Ultrasound can be used for measuring wind speed and direction, tank or channel fluid level, for measuring speed or direction, a device uses multiple detectors and calculates the speed from the relative distances to particulates in the air or water. To measure tank or channel level, the measures the distance to the surface of the fluid. Further applications include, humidifiers, sonar, medical ultrasonography, burglar alarms, non-destructive testing, the technology is limited by the shapes of surfaces and the density or consistency of the material. Foam, in particular, can distort surface level readings and this technology, as well, can detect approaching objects and track their positions. Ultrasonic transducers convert AC into ultrasound, as well as the reverse, ultrasonics, typically refers to piezoelectric transducers or capacitive transducers. Piezoelectric crystals change size and shape when a voltage is applied, AC voltage makes them oscillate at the same frequency, capacitive transducers use electrostatic fields between a conductive diaphragm and a backing plate. The beam pattern of a transducer can be determined by the active area and shape, the ultrasound wavelength. The diagrams show the fields of an unfocused and a focusing ultrasonic transducer in water. Since piezoelectric materials generate a voltage when force is applied to them, some systems use separate transmitters and receivers, while others combine both functions into a single piezoelectric transceiver. Ultrasound transmitters can also use non-piezoelectric principles, materials with this property change size slightly when exposed to a magnetic field, and make practical transducers. A capacitor microphone has a diaphragm that responds to ultrasound waves. Changes in the field between the diaphragm and a closely spaced backing plate convert sound signals to electric currents, which can be amplified. The diaphragm principle is used in the relatively new micro-machined ultrasonic transducers. These devices are fabricated using silicon micro-machining technology, which is useful for the fabrication of transducer arrays
26.
Current meter
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A current meter is oceanographic device for flow measurement by mechanical, tilt, acoustical or electrical means. Lagrangian current meters measure the displacement of a drifter, an unmoored buoy or a non-anchored ships actual position to the position predicted by dead reckoning. Eulerian current meters measure current passing a current meter. Mechanical current meters are based on counting the rotations of a propeller and are thus rotor current meters. A mid-20th-century realization is the Ekman current meter which drops balls into a container to count the number of rotations, the Roberts radio current meter is a device mounted on a moored buoy and transmits its findings via radio to a servicing vessel. Savonius current meters rotate around an axis in order to minimize error introduced by vertical motion. There are two types of acoustic current meters, Doppler and Travel Time. Both methods use a transducer to emit a sound into the water. The ADCPs use the time of the sound to determine the position of the moving particles. Single-point devices use again the Doppler shift, but ignoring the traveling times, such a single-point Doppler Current Sensor has a typical velocity range of 0 to 300 cm/s. The devices are equipped with additional optional sensors. Travel time instruments determine water velocity by at least two signals, one up stream and one down stream. By precisely measuring the time to travel from the emitter to the receiver, by using multiple paths, the water velocity can be determined in three dimensions. Travel time meters are more accurate than Doppler meters. Doppler meters have the advantage that they can determine the velocity at a considerable range. The physics behind, Charged particles are moving with the currents in the magnetic field of the Earth which is perpendicular to the movement. Using Faradays law of induction, it is possible to evaluate the variability of the horizontal flow by measuring the induced electric currents. The method has a minor vertical weighting effect due to small conductivity changes at different depths, Tilt current meters operate under the drag-tilt principle and are designed to either float or sink depending on the type
27.
Acoustic Doppler current profiler
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The term ADCP is a generic term for all acoustic current profilers although the abbreviation originates from an instrument series introduced by RD Instruments in the 1980s. The working frequencies range of ADCPs range from 38 kHz to several Megahertz, ADCPs contain piezoelectric transducers to transmit and receive sound signals. The traveling time of waves gives an estimate of the distance. The frequency shift of the echo is proportional to the velocity along the acoustic path. To measure 3D velocities, at least three beams are required, in rivers, only the 2D velocity is relevant and ADCPs typically have two beams. In recent years, more functionality has been added to ADCPs, an analog-to-digital converter and a digital signal processor are required to sample the returning signal in order to determine the Doppler shift. A temperature sensor is used to estimate the velocity at the instrument position using the seawater equation of state. This procedure assumes that the salinity has a constant value. Finally, the results are saved to memory or output online to an external display software. Three common methods are used to calculate the Doppler shift and thus the velocity along the acoustic beams. The first method uses a monochromatic transmit pulse and is referred to as incoherent or narrowband, the method is robust and provides good quality mean current profiles but has limited space-time resolution. When the transmit pulse consists of coded elements that are repeated and this method improves the space-time resolution by a factor of 5. Commercially, this method was protected by US patent 5615173 until 2011, the pulse-to-pulse coherent method relies on a sequence of transmit pulses where the echo from subsequent pulses are assumed not to interfere with each other. This method is applicable for very short profiling ranges but the corresponding improvement in space time resolution is of order 1000. Depending on the mounting, one can distinguish between side-looking, downward- and upward-looking ADCPs, a bottom-mounted ADCP can measure the speed and direction of currents at equal intervals all the way to the surface. Mounted sideways on a wall or bridge piling in rivers or canals, in very deep water they can be lowered on cables from the surface. The primary usage is for oceanography, the instruments can also be used in rivers and canals to continuously measure the discharge. Mounted on moorings within the column or directly at the seabed, water current
28.
River Dove, Central England
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The River Dove is the principal river of the southwestern Peak District, in the Midlands of England and is around 45 miles in length. It rises on Axe Edge Moor near Buxton and flows south to its confluence with the River Trent at Newton Solney. From there, its waters reach the North Sea via the Humber Estuary, for almost its entire course it forms the boundary between the counties of Staffordshire and Derbyshire. The river meanders past Longnor and Hartington and cuts through a set of stunning limestone gorges, Beresford Dale, the river is a famous trout stream. Charles Cottons Fishing House, which was the inspiration for Izaak Waltons The Compleat Angler, the rivers name is now usually pronounced to rhyme with love, but its original pronunciation rhymed with rove. This pronunciation is used by some residents of the lower reaches of the river. From Hartington to its confluence with the River Manifold at Ilam, Dovedale is also particularly used for the name of that section between the stepping stones under Thorpe Cloud and Milldale. The Dovedale gorge is considered so scenic that it attracts a million visitors a year, good riverside paths make the whole route accessible to walkers. Much of the dale is in the ownership of the National Trust, Dovedale itself was acquired in 1934, with successive properties being added until 1938, and Wolfscote Dale in 1948. Dovedale was declared a nature reserve in 2006. Dovedales attractions include rock pillars such as Ilam Rock, Viators Bridge, once the river leaves Dovedale it combines with the Manifold and enters a wider valley near Thorpe. The valley increases in size as the river south to reach Mapleton and then Mayfield. At this point it is joined by the Bentley Brook, and then nearby at Church Mayfield, the Dove now flows in a south-westerly direction, passing Norbury and Ellastone, where it turns south until it reaches Rocester. To the south of the village, at Combridge it is joined by its largest tributary the River Churnet, the river continues east passing the villages of Marston, Rolleston and Egginton, where it is joined by its last tributary, the Hilton Brook
29.
Izaak Walton
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Izaak Walton was an English writer. Best known as the author of The Compleat Angler, he wrote a number of short biographies that have been collected under the title of Waltons Lives. Walton was born at Stafford c,1594, the traditional 9 August 1593 date is based on a misinterpretation of his will, which he began on 9 August 1683. The register of his baptism gives his fathers name as Gervase and his father, who was an innkeeper as well as a landlord of a tavern, died before Izaak was three. His mother then married another innkeeper by the name of Bourne and he is believed to have been educated in Stafford before moving to London in his teens. He is often described as an ironmonger, but he trained as a linen draper and he had a small shop in the upper storey of Thomas Greshams Royal Burse or Exchange in Cornhill. In 1614 he had a shop in Fleet Street, two doors west of Chancery Lane in the parish of St Dunstans and he became verger and churchwarden of the church, and a friend of the vicar, John Donne. He joined the Ironmongers Company in November 1618, Waltons first wife was Rachel Floud, a great-great-niece of Archbishop Cranmer. He soon remarried, to Anne Ken, who appears as the pastoral Kenna of The Anglers Wish, she was a stepsister of Thomas Ken, afterwards bishop of Bath, after the Royalist defeat at Marston Moor in 1644, Walton retired from his trade. He went to live just north of his birthplace, at a spot between the town of Stafford and the town of Stone, where he had some land edged by a small river. His new land at Shallowford included a farm, and a parcel of land, however by 1650 he was living in Clerkenwell, the first edition of his book The Compleat Angler was published in 1653. His second wife died in 1662, and was buried in Worcester Cathedral, one of his daughters married Dr Hawkins, a prebendary of Winchester. After 1662 he found a home at Farnham Castle with George Morley, bishop of Winchester, to whom he dedicated his Life of George Herbert and he sometimes visited Charles Cotton in his fishing house on the Dove. Walton died in his daughters house at Winchester, and was buried in Winchester Cathedral, Walton left his property at Shallowford in Staffordshire for the benefit of the poor of his native town. He had purchased Halfhead Farm there in May 1655, the cost of Shallowford was £350, and the property included a farmhouse, a cottage, courtyard, garden and nine fields along which a river ran. Part of its attraction may have been that the River Meece, the farm was let to tenants, and Walton kept the excellent fishing. The cottage is now a Walton Museum, the ground floor of the museum is set-out in period, with information boards covering Waltons life, his writings and the story of the Izaak Walton Cottage. Upstairs a collection of fishing related items is displayed, the earliest dating from the century, while a room is dedicated to his Lives
30.
River Thames
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The River Thames is a river that flows through southern England, most notably through London. At 215 miles, it is the longest river entirely in England and it also flows through Oxford, Reading, Henley-on-Thames and Windsor. The lower reaches of the river are called the Tideway, derived from its tidal reach up to Teddington Lock. It rises at Thames Head in Gloucestershire, and flows into the North Sea via the Thames Estuary, the Thames drains the whole of Greater London. Its tidal section, reaching up to Teddington Lock, includes most of its London stretch and has a rise, in Scotland, the Tay achieves more than double the average discharge from a drainage basin that is 60% smaller. Along its course are 45 navigation locks with accompanying weirs and its catchment area covers a large part of South Eastern and a small part of Western England and the river is fed by 38 named tributaries. The river contains over 80 islands, in 2010, the Thames won the largest environmental award in the world – the $350,000 International Riverprize. The Thames, from Middle English Temese, is derived from the Brittonic Celtic name for the river, Tamesas, recorded in Latin as Tamesis and yielding modern Welsh Tafwys Thames. It has also suggested that it is not of Celtic origin. A place by the river, rather than the river itself, indirect evidence for the antiquity of the name Thames is provided by a Roman potsherd found at Oxford, bearing the inscription Tamesubugus fecit. It is believed that Tamesubugus name was derived from that of the river, tamese was referred to as a place, not a river in the Ravenna Cosmography. The rivers name has always pronounced with a simple t /t/, the Middle English spelling was typically Temese. A similar spelling from 1210, Tamisiam, is found in the Magna Carta, the Thames through Oxford is sometimes called the Isis. Ordnance Survey maps still label the Thames as River Thames or Isis down to Dorchester, richard Coates suggests that while the river was as a whole called the Thames, part of it, where it was too wide to ford, was called *lowonida. An alternative, and simpler proposal, is that London may also be a Germanic word, for merchant seamen, the Thames has long been just the London River. Londoners often refer to it simply as the river in such as south of the river. Thames Valley Police is a body that takes its name from the river. The marks of human activity, in cases dating back to Pre-Roman Britain, are visible at various points along the river
31.
River Lea
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It is one of the largest rivers in London and the easternmost major tributary of the Thames. Its valley creates a chain of marshy ground along its lower length, much of which has been used for gravel and mineral extraction, reservoirs. The river has been canalised to provide a route for boats into eastern Hertfordshire. While the lower Lea remains somewhat polluted, its stretch and tributaries. A diversion known as the New River, opened in 1613 and its origins in the Chilterns contribute to the extreme hardness of London tap water. The name of the River Lea was first recorded in the 9th century, spellings from the Anglo-Saxon period include Ligan in 880 and Lygan in 895, and in the early medieval period it is usually Luye or Leye. It seems to be derived from a Celtic root lug-meaning bright or light which is also the derivation of a name for a deity, a simpler derivation may well be the Brythonic word cognate with the modern Welsh Li pronounced Lea which means a flow or a current. The spelling Lea predominates west of Hertford, but both spellings are used from Hertford to the River Thames, the Lee Navigation was established by Acts of Parliament and only that spelling is used in this context. The Lee Valley Regional Park Authority also uses this spelling for leisure facilities, however, the spelling Lea is used for road names, locations and other infrastructure in the capital, such as Leamouth, Lea Bridge, the Lea Valley Walk and the Lea Valley Railway Lines. This spelling is used in geology, archaeology, etc. to refer to the Lea Valley. The divergent spellings of the river are also reflected in the place-names of Luton and Leyton, both mean farmstead on the River Lea. The source is said to be at Well Head inside Wauluds Bank at Leagrave, but there the River Lea is also fed by Houghton Brook. It forms the boundary between the counties of Middlesex and Essex, and was used for part of the Danelaw boundary. It also forms part of the boundary between Essex and Hertfordshire, for much of its distance the river runs within or as a boundary to the Lee Valley Park. Between Tottenham and Hackney the Lea feeds Tottenham Marshes, Walthamstow Marshes, in their early days, Tottenham Hotspur and Leyton Orient played their matches as football amateurs on the Marshes. South of Hackney Wick the rivers course is split, running almost completely in man made channels flowing through an area that was once an industrial zone. Inside Greater London below Enfield Lock the river forms the boundary with the former Royal Small Arms Factory, now known as Enfield Island Village, just downstream the river is joined by the River Lee Flood Relief Channel. At Tottenham Hale there is a set of reservoirs, Lockwood Reservoir, High Maynard Reservoir, Low Maynard Reservoir, Walthamstow Reservoirs, East Warwick Reservoir
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Environment Agency
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The Environment Agencys stated purpose is, to protect or enhance the environment, taken as a whole so as to promote the objective of achieving sustainable development. Protection of the environment relates to such as flood and pollution. The vision of the Agency is of a rich, healthy and diverse environment for present and it is organised into eight directorates that report to the chief executive. There are two policy and process directorates, one deals with Flood and Coastal Risk Management and the other with Environment and Business. These are backed up by the Evidence directorate, the fourth directorate is a single Operations delivery unit, responsible for national services, and line management of all the Regional and Area staff. The remaining directorates are central shared service groups for Finance, Legal Services, Resources, in support of its aims, the Agency acts as an operating authority, a regulatory authority and a licence authority. The agency is funded in part from the UK government Department for Environment, Food, funding for asset management and improvement and acquisition of flood risk management assets has traditionally come from local authorities via Flood Defence Committees. This was then effectively repaid by central Government in later years as part of the Formula Spending Share, in 2005 this was simplified by making a direct transfer from Treasury to the Environment Agency in the form of Flood Defence Grant in Aid. The Environment Agencys total funding in 2007–08 was £1,025 million, of that total, £628 million was provided in the form of flood defence grant-in-aid from government. In addition, £347 million was raised through statutory charging schemes and flood defence levies, in 2007–08 had an operational budget of £1.025 billion, of which £628m was grant from the Agencys sponsoring Government Departments. Approximately half the Agencys expenditure is on flood risk management, of the remainder, 12% goes to water resources, and 6% to other water functions including navigation and wildlife. Its chief executive is Sir James Bevan, Sir Philip Dilley resigned as chairman on 11 January 2016, with Emma Howard Boyd becoming acting chair. The Environment Agency was created by the Environment Act 1995, and it had responsibility for the whole of England and Wales but with specifically designated border arrangements with Scotland covering the catchment of the River Tweed. All of the bodies were disbanded and the local authorities relinquished their waste regulatory role. At the same time, the Agency took responsibility for issuing warnings to the public. On 1 April 2013, that part of the Environment Agency covering Wales was merged into Natural Resources Wales, the Environment Agency is the principal flood risk management operating authority. It has the power to flood risk from designated main rivers. These functions in relation to other rivers in England are undertaken by Local Authorities or internal drainage boards, the Environment Agency is also responsible for increasing public awareness of flood risk, flood forecasting and warning and has a general supervisory duty for flood risk management
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Scottish Environment Protection Agency
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The Scottish Environment Protection Agency is Scotland’s environmental regulator and flood warning authority. Its main role is to protect and improve Scotlands environment, one of the ways SEPA does this is through the NetRegs environmental guidance service. It protects communities by regulating activities that can cause pollution and by monitoring the quality of Scotlands air, land. The regulations it implements also cover the storage, transport and disposal of radioactive materials, SEPA is an executive non-departmental public body of the Scottish Government. SEPA was established in 1996 by the Environment Act 1995 and is responsible for the protection of the environment in Scotland. SEPA is a member of SEARS, sEPA’s mission statement is to be an environmental regulator and an effective and influential authority on the environment. SEPA provides a system of protection for Scotland that aims to improve the environment. So that it can achieve its mission and aims, SEPA has created a Corporate Plan which lists its priorities. SEPA employs around 1,300 staff who are involved in protecting Scotlands environment, the agency operates through three directorates, The previously named Environmental Protection and Improvement Directorate is now known as Operations after an internal reorganisation in April 2010. The Environmental and Organisational Strategy Directorate and Environmental Science Directorate were merged in a reorganisation took place in April 2010. Communications is also part of this directorate, because of its role within the organisation. The Agency Board legally constitutes SEPA and board members are appointed by Scottish Ministers, sEPA’s Chairman and a Deputy Chairman are appointed by Scottish Ministers and the Agency Board appoints a Chief Executive. SEPA used to have Regional Boards that undertook local engagement with customers, partners and stakeholders, however, Regional Boards had been phased out by January 2010 and SEPA has since adopted a new approach to engage with its stakeholders at a local level. SEPA operates Scotlands flood warning service and this is a 24-hour, 7-day-a-week, information service which includes direct warnings by phone and online flood warnings and flooding updates through its dedicated telephone number 08459881188. As the name suggests, the Floodline service is designed to give the early warning of likely flooding in specific areas. The service also gives advice on what to do before, during, the Environment Agency operates the Floodline service for England and Wales. In March 2011 SEPA enhanced its provision with a direct extension to its Floodline service. This sends flood warning information for a geographical area direct to customers who have registered a mobile or landline telephone number
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Hydrograph
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A hydrograph is a graph showing the rate of flow versus time past a specific point in a river, or other channel or conduit carrying flow. The rate of flow is typically expressed in meters or cubic feet per second. It can also refer to a showing the volume of water reaching a particular outfall. Graphs are commonly used in the design of sewerage, more specifically, the discharge is measured at a specific point in a river and is typically time variant. The end of stormflow and the return to groundwater-derived flow is taken as the point of inflection of the recession limb. The recession limb represents the withdrawal of water from the built up in the basin during the earlier phases of the hydrograph. k. a. However, the process of separating “baseflow” from “direct runoff” is an inexact science, in part this is because these two concepts are not, themselves, entirely distinct and unrelated. Therefore, separation of a purely “baseflow component” in a hydrograph is a somewhat arbitrary exercise, nevertheless, various graphical and empirical techniques have been developed to perform these hydrograph separations. A unit hydrograph is the hypothetical unit response of a watershed to an input of rainfall. It can be defined as the runoff hydrograph resulting from one unit of effective rainfall occurring uniformly over that watershed at a uniform rate over a unit period of time. As a UH is applicable only to the direct component of a hydrograph. A UH is specific to a watershed, and specific to a particular length of time corresponding to the duration of the effective rainfall. That is, the UH is specified as being the 1-hour, 6-hour, or 24-hour UH, thus, for a given watershed, there can be many unit hydrographs, each one corresponding to a different duration of effective rainfall. The UH technique provides a practical and relatively easy-to-apply tool for quantifying the effect of a unit of rainfall on the runoff from a particular drainage basin. UH theory assumes that a watersheds runoff response is linear and time-invariant, in the real world, none of these assumptions are strictly true. Nevertheless, application of UH methods typically yields an approximation of the flood response of natural watersheds. This allows for a straightforward calculation of the hydrograph response to any arbitrary rain event. An instantaneous unit hydrograph is a refinement of the concept, for an IUH
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Snoqualmie River
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The Snoqualmie River is a 45-mile long river in King County and Snohomish County in the U. S. state of Washington. After the falls the river north through rich farmland and the towns of Fall City, Carnation. The Snohomish River empties into Puget Sound at Everett, many of the Snoqualmie Rivers headwaters originate as snowmelt within the Alpine Lakes Wilderness. The proposal would give the Pratt River National Wild and Scenic River status. It then flows west for a bit before turning northwest and continuing in that direction until it merges with the Snoqualmie River Proper just above Snoqualmie Falls. It drops over a total of 6 waterfalls and it receives the waters of the Taylor River and the Pratt River in short order about halfway between its source and its mouth. It has one major waterfall along its course, the upper reaches of the Middle Fork, Taylor, and Pratt river valleys are within the boundaries of the Alpine Lakes Wilderness area. The Middle Fork Valley is a recreational area since it is accessible during the winter due to its low altitude. For many years the Middle Fork Road extended 24 miles to Hardscrabble Creek, the gate at Dingford Creek was a controversial part of the Access and Travel Management plan adopted by the US Forest Service in 2005. Much of the route is on the 1920s and 30s era railroad grade of the North Bend Timber Company. The paved portion of the Middle Fork road was extended by 9.7 miles during a 3-year construction project from 2014-2016, the Middle Fork Valley was heavily logged starting in 1923 and continued up through the 1970s. The obvious railroad grades, pilings, and related debris are from the North Bend Timber Companys companys activity from 1923 to 1941, the North Fork, approximately 28 miles long, originates at the outlet of small, rarely visited Lake Kanim, 47°39′41″N 121°28′58″W. Almost directly after exiting the lake it drops over Kanim Falls, the river then flows east before making a wide turn north. Just before its confluence with the Middle Fork the river flows through a canyon near Ernies Grove, there are several waterfalls within this canyon including Fantastic Falls. The Snoqualmie River has quite a few major waterfalls, by far the most famous waterfall in Washington, receiving over 1 million visitors every year, is the 268 ft high Snoqualmie Falls. However, the three forks of the upper Snoqualmie River also have notable waterfalls, the north fork has Fantastic Falls and Kanim Falls. The middle fork has Nellie Falls, and, the south fork has Twin Falls, Middle Twin Falls, Upper Twin Falls, Weeks Falls, Upper Weeks Falls, Denny Camp Falls, Franklin Falls, and Fall-into-the-Wall Falls. Snoqualmie Falls was featured on the television series Twin Peaks, shots of upriver Snoqualmie also feature in some of the shows title sequences
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U.S. Geological Survey
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The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its resources. The organization has four science disciplines, concerning biology, geography, geology. The USGS is a research organization with no regulatory responsibility. The USGS is a bureau of the United States Department of the Interior, the USGS employs approximately 8,670 people and is headquartered in Reston, Virginia. The USGS also has major offices near Lakewood, Colorado, at the Denver Federal Center, the current motto of the USGS, in use since August 1997, is science for a changing world. The agencys previous slogan, adopted on the occasion of its anniversary, was Earth Science in the Public Service. Prompted by a report from the National Academy of Sciences, the USGS was created, by a last-minute amendment and it was charged with the classification of the public lands, and examination of the geological structure, mineral resources, and products of the national domain. This task was driven by the need to inventory the vast lands added to the United States by the Louisiana Purchase in 1803, the legislation also provided that the Hayden, Powell, and Wheeler surveys be discontinued as of June 30,1879. Clarence King, the first director of USGS, assembled the new organization from disparate regional survey agencies, after a short tenure, King was succeeded in the directors chair by John Wesley Powell. Administratively, it is divided into a Headquarters unit and six Regional Units, Other specific programs include, Earthquake Hazards Program monitors earthquake activity worldwide. The National Earthquake Information Center in Golden, Colorado on the campus of the Colorado School of Mines detects the location, the USGS also runs or supports several regional monitoring networks in the United States under the umbrella of the Advanced National Seismic System. The USGS informs authorities, emergency responders, the media, and it also maintains long-term archives of earthquake data for scientific and engineering research. It also conducts and supports research on long-term seismic hazards, USGS has released the UCERF California earthquake forecast. The USGS National Geomagnetism Program monitors the magnetic field at magnetic observatories and distributes magnetometer data in real time, the USGS operates the streamgaging network for the United States, with over 7400 streamgages. Real-time streamflow data are available online, since 1962, the Astrogeology Research Program has been involved in global, lunar, and planetary exploration and mapping. USGS operates a number of related programs, notably the National Streamflow Information Program. USGS Water data is available from their National Water Information System database
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Natural resources
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Natural resources are resources that exist without actions of humankind. This includes all valued characteristics such as magnetic, gravitational, on earth it includes, sunlight, atmosphere, water, land along with all vegetation and animal life that naturally subsists upon or within the heretofore identified characteristics and substances. Particular areas such as the rainforest in Fatu-Hiva are often characterized by the biodiversity and geodiversity existent in their ecosystems, Natural resources may be further classified in different ways. Natural resources are materials and components that can be found within the environment, every man-made product is composed of natural resources. Some natural resources such as sunlight and air can be found everywhere, however, most resources only occur in small sporadic areas, and are referred to as localised resources. There are very few resources that are considered inexhaustible – these are solar radiation, geothermal energy, the vast majority of resources are theoretically exhaustible, which means they have a finite quantity and can be depleted if managed improperly. There are various methods of categorizing natural resources, these include source of origin, stage of development, fossil fuels such as coal and petroleum are also included in this category because they are formed from decayed organic matter. Abiotic – Abiotic resources are those that come from non-living, non-organic material, examples of abiotic resources include land, fresh water, air and heavy metals including ores such as gold, iron, copper, silver, etc. For example, petroleum occurs with sedimentary rocks in various regions, Actual resources — Actual resources are those that have been surveyed, their quantity and quality determined and are being used in present times. The development of a resource, such as wood processing depends upon the technology available. Reserve resources — The part of a resource which can be developed profitably in the future is called a reserve resource. Stock resources — Stock resources are those that have been surveyed, renewability is a very popular topic and many natural resources can be categorized as either renewable or non-renewable, Renewable resources — Renewable resources can be replenished naturally. Some of these resources, like sunlight, air, wind, water, etc. are continuously available, though many renewable resources do not have such a rapid recovery rate, these resources are susceptible to depletion by over-use. Non-renewable resources – Non-renewable resources either form slowly or do not naturally form in the environment, minerals are the most common resource included in this category. Some resources actually naturally deplete in amount without human interference, the most notable of these being radio-active elements such as uranium, of these, the metallic minerals can be re-used by recycling them, but coal and petroleum cannot be recycled. Once they are used they take millions of years to replenish. Resource extraction involves any activity that withdraws resources from nature and this can range in scale from the traditional use of preindustrial societies, to global industry. Extractive industries are, along with agriculture, the basis of the sector of the economy
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Velocity
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The velocity of an object is the rate of change of its position with respect to a frame of reference, and is a function of time. Velocity is equivalent to a specification of its speed and direction of motion, Velocity is an important concept in kinematics, the branch of classical mechanics that describes the motion of bodies. Velocity is a vector quantity, both magnitude and direction are needed to define it. The scalar absolute value of velocity is called speed, being a coherent derived unit whose quantity is measured in the SI system as metres per second or as the SI base unit of. For example,5 metres per second is a scalar, whereas 5 metres per second east is a vector, if there is a change in speed, direction or both, then the object has a changing velocity and is said to be undergoing an acceleration. To have a constant velocity, an object must have a constant speed in a constant direction, constant direction constrains the object to motion in a straight path thus, a constant velocity means motion in a straight line at a constant speed. For example, a car moving at a constant 20 kilometres per hour in a path has a constant speed. Hence, the car is considered to be undergoing an acceleration, Speed describes only how fast an object is moving, whereas velocity gives both how fast and in what direction the object is moving. If a car is said to travel at 60 km/h, its speed has been specified, however, if the car is said to move at 60 km/h to the north, its velocity has now been specified. The big difference can be noticed when we consider movement around a circle and this is because the average velocity is calculated by only considering the displacement between the starting and the end points while the average speed considers only the total distance traveled. Velocity is defined as the rate of change of position with respect to time, average velocity can be calculated as, v ¯ = Δ x Δ t. The average velocity is less than or equal to the average speed of an object. This can be seen by realizing that while distance is always strictly increasing, from this derivative equation, in the one-dimensional case it can be seen that the area under a velocity vs. time is the displacement, x. In calculus terms, the integral of the velocity v is the displacement function x. In the figure, this corresponds to the area under the curve labeled s. Since the derivative of the position with respect to time gives the change in position divided by the change in time, although velocity is defined as the rate of change of position, it is often common to start with an expression for an objects acceleration. As seen by the three green tangent lines in the figure, an objects instantaneous acceleration at a point in time is the slope of the tangent to the curve of a v graph at that point. In other words, acceleration is defined as the derivative of velocity with respect to time, from there, we can obtain an expression for velocity as the area under an a acceleration vs. time graph
39.
Geostationary Operational Environmental Satellite
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Spacecraft and ground-based elements of the system work together to provide a continuous stream of environmental data. The GOES system uses geosynchronous satellites which—since the launch of SMS-1 in 1974—have been an element of U. S. weather monitoring and forecasting. GOES data can be accessed using the SPEDAS software, three GOES satellites are currently available for operational use, GOES13 is designated GOES-East, currently located at 75°W. It was placed in orbit on 24 May 2006, underwent Post-Launch Testing through early 2007, GOES14 is currently in storage at 90°W. It was temporarily designated GOES-East due to difficulties with GOES-13, and moved toward the GOES-East location. Several GOES satellites are still in orbit, either inactive or re-purposed, GOES-3 is no longer used for weather operations, but is a critical part of the communication links between the United States and Amundsen–Scott South Pole Station. Geostationary satellites cannot ordinarily be seen at all from the poles, when station-keeping fuel is depleted, solar and lunar perturbations increase the satellites inclination so that its ground track begins to describe an analemma. This usually ends the satellites primary mission, but when the inclination is high enough, the satellite may begin to rise above the polar horizons at the extremes of the figure-8, as is the case for GOES-3. A nine-meter dish was constructed at the station, and communication with the satellite is currently possible for five hours per day. Data rates are around 2.048 Mbit/s bi-directional under optimum conditions, gOES-8 is in a parking orbit, currently drifting about 4°W daily. It was decommissioned on April 1,2003, and deactivated on May 5,2004, Weather data was lost for 13 days from GOES-12 on December 4,2007 when it performed a standard station-keeping maneuver. GOES-11 initially took full disk images to cover the lost data until a plan could be implemented. On December 5,2007, GOES-10 was moved from South America operations to temporarily replace GOES-12 as the GOES-EAST operational satellite, on 9 December, communication with GOES-10 was also temporarily lost, but communication was resumed via a backup antenna. GOES-12 was successfully reactivated and moved back to operation following a thrust maneuver on 17 December. The trouble was traced to a leaking thruster valve, which pushed the satellite incorrectly, emergency procedures were executed to cut off the valve, and a redundant thruster was activated to restore the location of the satellite. GOES-10 was decommissioned on December 2,2009 and was boosted to a graveyard orbit and it no longer had the fuel for required maneuvers to keep it on station. It joins GOES8 and 9 which are already in graveyard orbits, with the cessation of GOES-10s duties, GOES-13 has replaced GOES-12 as GOES-East. GOES-12 was then moved to 60° W and resume South American duties for GOES-10, gOES-11 had a partial failure 6 Dec 2011, was decommissioned on 16 Dec 2011 and was boosted into a graveyard orbit
