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Marshes: Salt and Brackish
Published in Yeqiao Wang, Wetlands and Habitats, 2020
Despite the variety of ecosystem services provided by salt and brackish marshes, humans have had considerable negative impacts on these systems [19,27,28]. Loss of coastal marshes can be attributed to a number of factors that vary over local, regional, and global scales [28]. At local scales, marshes have been converted for agriculture and development purposes through draining, diking, or diverting water away from the marsh. Some major cities, including Boston, San Francisco, and London, are built on filled or drained wetlands. Another local-scale impact from humans is that of non-native invasions. For example, Spartina spp. have been introduced into estuaries worldwide, transforming mudflats into marshes [29,30]. This reduces habitat for seagrass, oysters, fish, and foraging birds. At regional scales, extraction of groundwater, oil, and gas has caused subsidence, leading to the submergence and erosion of hundreds of square kilometers of salt marsh habitat in the Chesapeake Bay, San Francisco Bay, and Gulf of Mexico. Finally, at global scales, sea-level rise caused by warming temperatures threatens coastal marshes if they are unable to maintain their elevation above sea level through sediment accretion and/or if brackish marshes become more saline.
Energy Basics/Foundation for Understanding
Published in Dale R. Patrick, Stephen W. Fardo, Ray E. Richardson, Brian W. Fardo, Energy Conservation Guidebook, 2020
Dale R. Patrick, Stephen W. Fardo, Ray E. Richardson, Brian W. Fardo
A gas pressure that is always present is exerted on the earth by the weight of the atmosphere above us. Because of the earth’s gravitational pull, gases in the air tend to exert a continuous force on the surface of the earth. This force per unit area is called atmospheric pressure. Atmospheric pressure at sea level is 14.7 psi or 101.36 kPa. This value is normally used as a reference or a comparison with other pressure values. Atmospheric pressure decreases in value as the height above sea level increases. Atmospheric pressure is measured with an instrument known as a barometer. Barometric pressure values in specific localities are subject to a great deal of change due to variations in weather conditions.
Karkams borehole injection tests: Results from injection into a low-permeability fractured granitic aquifer{PRIVATE}
Published in Peter J. Dillon, Management of Aquifer Recharge for Sustainability, 2002
The groundwater salinity in the region generally increases from east to west and is directly related to elevation above sea level, which in turn, controls precipitation (Visser, et al. 1995). The fluoride content of the groundwater in the area is generally high which is not uncommon in granitic and gneissic terrains. The trend generally follows that of salinity, with the highest values found in the low lying areas in the west (Visser, et al., 1995). The fluoride concentration of 2.8 mg/L at borehole G39002 is relatively low in comparison to some boreholes in the west which have values up to 5.3 mg/L.
Multicriteria decision and sensitivity analysis support for optimal airport site locations in Ordu Province, Turkey
Published in Annals of GIS, 2023
H. Ebru Çolak, Tuğba Memişoğlu Baykal, Nihal Genç
Another site selection parameter for the airport is elevation. This concept, referred to as airport altitude in the literature, is the elevation of the highest point of the landing site at the airport above sea level. Unfavourable situations that affect aircraft may occur at airports located at elevations too high. As aircraft go up, the air weakens, and the atmospheric pressure decreases. As a result, the aircraft has difficulty in gaining lift at take-off. Airports with this feature need longer runways in response to the low air pressure problem, and thus an increase in take-off speed is required. In addition, weak, less dense air and low atmospheric pressure make it difficult for aircraft to slow down. This may cause hazards. On the other hand, lower air density causes less friction in the aircraft, which means less fuel at higher altitudes (Horonjeff et al. 2010).
Application of Archimedean copula in the non-isothermal nth order distributed activation energy model
Published in Biofuels, 2019
Alok Dhaundiyal, Suraj B. Singh, Muammel M. Hanon
In the summer season, pine needles samples were collected in a small burlap from Teri Garhwal, Uttarakhand, India and thereafter they were kept under direct sunlight for drying. The latitude and longitude in the field of working are 30.30°N and 78.56°E. The altitude of the forest is 2286 m above sea level. Thermogravimetric analysis was performed with a sample of pine needles. In order to attain pyrolysis conditions, nitrogen was used as a purge and protective gas to prevent the micro-balance from possible ingression of pollutants. The volume flow rate of nitrogen was set to 200 ml min−1. The experiments were performed by using a thermogravimetric analyser (SII 6300 EXSTAR in Indian Institute of Technology, Roorkee, India. The sample of 10.54 mg of pine needles was heated in a crucible pan of alumina at a heating rate of 5°C min−1, 10°C min−1 and 15°C min−1. To prevent the buoyancy effect, correction measurements were used. Ultimate analysis of the pine needles was carried out to evaluate the percentage of carbon, hydrogen, oxygen and sulphur (Table 1) with the help of a CHNO-S analyser at The Energy and Resources Institute, New Delhi, India. Ash content was evaluated by proximate analysis of the sample at TERI laboratory. To measure the sample and furnace temperatures, thermocouple types ‘R’ were used. A bomb calorimeter was used to obtain calorific value of pine needles at constant volume. Chemical composition (dry basis %) and calorific value of pine needles are illustrated in Table 1.
Goal Programming-Based Two-Tier Multi-Criteria Decision-Making Approach for Wind Turbine Selection
Published in Applied Artificial Intelligence, 2019
Shafiqur Rehman, Salman A. Khan
The study was carried out for a potential site of Dhulom located in the western region of Saudi Arabia. Dhulom has an altitude of 1117 m above sea level. The data for the study was collected over a period of 4 years, and information relevant to the study was extracted from the data. This information composed of speed of wind and mean energy output for different turbines and was measured at a step of 5 m for hub height. A C++-based program was developed to perform the simulations. The simulator performs the MCDM calculations using the input data and applies the proposed goal programming approach to generate the decision output. For each set of turbine-specific data, the value which produced the lowest overall deviation was declared as the best solution (which corresponds to the best trade-off between the three decision criteria). Twenty different turbine models from having different rated powers and manufacturers were considered. Of the 20 turbines, seven turbines had rated power output in the range of 500–750 kW, 6 turbines had rated power in the range of 1000–1250 kW, while the other 7 turbines possessed rated power output of 2000 kW. Tables 1–3 provide the technical specifications of these turbines.