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791.
792.
K. Satyanarayana M. Borah P. G. Rao 《Journal of Loss Prevention in the Process Industries》1991,4(5):344-347
Various models of fireball diameter have been evaluated by statistical techniques. The model of Gayle for fireball diameter estimation showed good agreement between the predicted and experimental data. The models relating to fireball duration, transmissivity and view factor have been selected based on their relative merits. A user interactive computer program has been developed to predict thermal hazards from fireballs in chemical process industries. 相似文献
793.
794.
795.
The US Bureau of Mines has investigated the resource potential of 201 phosphate mines and depositee in 28 market economy countries and 17 mines and deposits in the USSR and China. The 201 mines and deposits contain an estimated 34.2 billiong tonnes (t) of recoverable phosphate rock (at the demonstrated resource level), with Morocco and Western Sahara accounting for 61% (21 billion t) and with the USA accounting for 19% (6.4 billion t). The 17 mines and deposits evaluated in the USSR and China contain approximately 1.5 billion t of potentially recoverable phosphate rock. Potential annual capacity from low-cost, high-grade producing mines in the USA is estimated to decline significantly during the latter half of the next decade, and the US phosphate fertilizer industry will have to obtain phosphate rock by developing new, higher-cost, lower-grade mines or import phosphate rock to satisfy anticipated demand in the next century. Of the world's new production capacity that are likely to be developed over the next decade, slightly over one-third could be produced at an estimated 1981 cost of $40/t or less, and about two-thirds would cost in the $40 to $50 per tonne range (including a 15% rate of return). In comparison, most of the competing phosphate rock from producing mines in Morocco could be produced for less than $40/t. 相似文献
796.
M. G. Lloyd 《Journal of Environmental Planning and Management》1985,28(1):46-49
A central government Consultation Paper issued in 1984 argues the case for simplified planning zones. These are seen to offer greater speed and certainty to developers and are closely related to the Enterprise Zone concept. This paper examines the context to the proposal, reviews the details of the Consultation Paper, and identifies the nature of the response to the idea. 相似文献
797.
Remote sensing has emerged as one of the major techniques for the analysis and delineation of large floods. This analysis can provide data invaluable for the hydrological management of large river systems. A need for information on the extent of floodplain inundation for the lower reaches of the largest river in the UK was met by a search through Landsat images of floods and the analysis of the best example recorded. Automated classification of the Landsat imagery of this flood on the river Severn in 1977 was used to provide estimates of the extent and spatial distribution of inundation. Flood images were generated using the Plessey IDP 3000 image processor, and the maps derived accorded well with aerial photography and qualitative flood information. Three distinct floodplain environments were delineated and flood images produced by different spectral bands compared. Specific questions prompted by flood hazard management and concerning the processes and extent of flooding were answered by the Landsat data analysis. Management of the flood risk of large rivers is expensive and remote sensing data is a relatively cheap and effective way of monitoring control works and providing data for the prediction of the effects of future hydrological works. Remote sensing is a practical way in which spatial information concerning the behavior of large dynamic systems can be obtained both quickly and relatively cheaply. 相似文献
798.
Robert G. Striegl 《Journal of the American Water Resources Association》1987,23(6):985-996
ABSTRACT: A small lake in the Chicago Metropolitan Area was from 91 to 95 percent efficient in removing suspended sediment and from 76 to 94 percent efficient in removing copper, iron, lead, and zinc from urban runoff. Sediments accumulated in the lake in the form of an organic-rich mud at an average rate of 20 millimeters per year; this reduced lake storage and covered potential habitat for aquatic organisms. Copper, lead, and zinc concentrations were closely associated with suspended-sediment concentrations and with silt- and clay-sized fractions of lake sediment. Although concentrations of mercury and cadmium were near detection limits in runoff, measurable concentrations of these metals accumulated in the lake sediments. 相似文献
799.
Kenneth G. Maxey Norman H. Starler 《Journal of the American Water Resources Association》1987,23(5):749-759
ABSTRACT: In the past, development of Federal water resource projects depended heavily or exclusively on Federal financing of construction costs. However, pressures on the Federal budget, environmental issues, and the notion that there are economic efficiency gains when beneficiaries of Federal water resource projects increase their cost share are causing changes. The case of the Central Arizona Project Plan 6 is a noteworthy example of the transition to more non-Federal participation in water resource development. This is because the non-Federal financing is to be provided for a project already under construction. The negotiation and terms of the Plan 6 financing agreement between the Department of the Interior and multiple interests in Arizona are used as an example of how Federal water project cost sharing is in a state of transition. The negotiation process is described, a financial analysis is provided, and the terms of the agreement and policy issues that were deliberated in the Executive Branch of the Federal Government are discussed. 相似文献
800.
G. M. Kondolf G. F. Cada M. J. Sale 《Journal of the American Water Resources Association》1987,23(5):927-935
Flushing flows are re1eses from dams designed to remove fine sediment from downstream spawning habitat. We evaluated flushing flows on reaches proposed for hydroelectric diversions on seven streams in the eastern Sierra Nevada, California, with wild populations of brown trout (Salmo trutta). The stream reaches are steep (average map slopes range from 7 to 17 percent), are dominated by boulder cascades, and afford few opportunities for gravel deposition. Methods for estimating flushing flows from flow records, developed from studies in other localities, produced widely differing results when applied to the study streams, probably reflecting differences in the hydrologic and geomorphic characteristics of the streams on which the methods were developed. Tracer gravel experiments demonstrated that all sampled gravels were washed out by the flows of 1986, a wet year. Size analyses of gravel samples and hydraulic data from field surveys were used in tractive-force calculations in an attempt to specify the flow required to flush the gravels. However, these calculations produced some unrealistic results because the flows were nonuniform in the study reaches. This suggests that the tractive-force approach may not be generally applicable to small, steep streams where nonuniform flow conditions prevail. 相似文献