933 resultados para road tunnel
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The classical Kepler problem is reviewed in depth in preparation to studying the Bohr model of the atom.
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In 2006, a study was initiated at the ISU Armstrong Research Farm (ARF) to evaluate the potential for growing high-value floricane and primocane type raspberries and blackberries in a high tunnel. The objectives were to determine if a high tunnel could be used to improve over-wintering of cold sensitive floricane types, and if the harvest season of primocane types could be advanced far enough ahead that they could replace the floricane types in such a production system. A second objective was to determine if these crops could be grown in a high tunnel without pesticides or minimum pesticide usage. This report summarizes the results for the 2009 through 2011growing seasons.
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High tunnels are simple, plastic-covered, passive solar-heated structures in which crops are grown in the ground. They are used by fruit and vegetable growers to extend the growing season and intensify production in cold climates. The covered growing area creates a desert-like environment requiring carefully monitored irrigation practices. In contrast, the exterior expanse of a high tunnel generates a large volume of water with every measurable rainfall. Each 1,000 ft of high tunnel roof will generate approximately 300 gallons from a half inch of rain. Unless the high tunnel site is elevated from the surrounding area or drainage tiles installed, or other drainage accommodations are made around the perimeter, the soil along the inside edge of the high tunnel is nearly continuously saturated. High volumes of water can also create an erosion problem. The objective of this project was to design and construct a system that enables growers using high tunnels in their production operation to reduce drainage problems, erosion, and crop loss due to excess moisture in and around their high tunnel(s) without permanent environmental and soil mediations.
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The 30 × 12 × 96 ft (W × H × L, 2,880 ft 2 ) high tunnel was planted and maintained as part of a high tunnel production budget project funded by a Specialty Crop Grant through the Iowa Department of Agriculture and Land Stewardship. Six growers throughout the state participated in the project with the objectives of creating an enterprise budgeting tool that estimates the costs and revenues associated with producing specific crops in a high tunnel, either as a single crop or multi-crop system. The budgeting tool will estimate the production cost and net profit per square foot in a high tunnel from mono-culture (one crop per tunnel) or multi-cropping, successionplanted systems. This report summarizes the findings from the high tunnel at the ISU Horticulture Research Station. The plantings in this high tunnel were used to collect labor and yield data as well as demonstrate a continuous, multi-cropping production system. A publication containing the enterprise budgeting tool, using this data and data collected from the other six farms, will be available through Iowa State University Extension and Outreach in the fall of 2012.
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High tunnels have been successfully used in Iowa to modify the climate and extend the growing season for tomatoes and other crops. Without the use of supplemental heat these ventilated, single layered plastic structures have typically increased average inside air temperatures by 10°F or more over outside temperatures for the growing season. The same tunnel, however, will only increase the daily low temperature by about 1 or 2°F, thus making early season high tunnel plantings without additional heat or plant coverings risky in Iowa. Fabric row covers are commonly used in high tunnels to provide for an additional 2-4°F frost protection during cold evenings. The recommended planting date for high tunnel tomatoes in Iowa has been about April 16 (4 to 5 weeks ahead of the recommended outside planting date). Producers are also advised to have some sort of plant covering material available to protect plants during a late spring frost.
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Colombia has oceanic waters, catchment areas, like lakes, cienagas and swamps, water flows, like rivers, gorges and streams, small rivers and groundwater. The oceanic waters are the Caribbean Sea-1600 km and the Pacific Ocean-1300 km that comprise the north and west continental territory, respectively. Actually the Region of Darién, geographically bounded by the Carribean Sea to the north is becoming to be focused by studies due to use conflicts and disputes about water and a forest reserve on its territories. Considering its location, strategic at northwestern Colombia, frontier region with Central America, several dynamics are imposed. One of them is the implantation of a road system entitled Connecting Road of the Americas. This fact means the construction of an infra-structure that will cross a special zone formed by swamps and jungle known as The Darién Gap. Evidences of such interests are revealed by projects like the constructions of Turbo's Port in the Atlantic Ocean, Department of Antioquia and Tribugá's Port in the Pacific Ocean, Department of Choco, the mountain road and the coastal conection Colombia-Venezuela attending to the main intentions of the central region of the department (Metropolitan Area of Aburrá Valley-AMVA). Human settlements form a productive system, based on small and medium familiar agriculture's production, corresponding to the western portion and piedmont of Abibe's mountain at its antioquian portion, alluvial plan that forms the rivers on this area, the littoral zone that delimits the Carribean Sea, the Darién and Baudó Mountains and the gulf that receives, among other waters, the ones from Atrato and León, as well as the exodus process constitutes a forced exit resulting from actions of several armed groups. It can be identified intense historical, cultural, political and environmental relations, specially the last one associated with strategic ecosystems that are fundamental for the hydric regulation of the region, as well as food safety of the local inhabitants. Results from two researches (UPB, 2007 y 2010) reveals this quick transformation in the spatial re-configuration, demographical and economical indicators and the exacerbated fight for resources, damaging the extractive vocation in the Region. Path to commerce of illegalities (drugs, guns) and to implementation of the agroindustrial project for biofuel production, cooperation program that involves Venezuela, Brazil and Colombia. Appropriation modes allow the existence of strategies since global interests revealing a development logic that privileges the conception of an artificialized nature. Since the smallest portion of rural areas, specific modes of resources exploration are linked to imposed interests of transnational corporations. Disparate consequences are going deeper evidenced by social, technical and nature transformations, envisioning risks for the habitability's condition