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251.
This is a case study that describes a survey of anglers that was used to assist in modifying fishing regulations for indigenous trout in the Snake River, Wyoming. A mail survey of anglers who purchased 1991 Wyoming fishing licenses in the two counties adjacent to the Snake River was conducted during fall 1992. Differences in angler preferences were noted between anglers who purchased licenses in two adjacent counties with different socioeconomic structures, as well as between residents and nonresidents in each county. Anglers who purchased licenses in Teton County, where there is extensive tourism and immigration by relatively wealthy residents, tended to be more specialized and less harvest oriented. Anglers in Lincoln County, which is largely agricultural and has substantially less tourism and immigration of residents, tended to fish in many different ways and indicated more desire to harvest fish. Anglers from the two counties segregated themselves; those from Teton County primarily used the upstream portion of the study reach, and those from Lincoln County primarily used a short downstream portion of the reach. Modification of fishing regulations to reduce harvest of spawning-size cutthroat trout in the Snake River probably was acceptable to most anglers due to spatial segregation and their attitudes toward harvest.The unit is jointly supported by the University of Wyoming, the Wyoming Game and Fish Department, and the National Biological Survey.  相似文献   
252.
ABSTRACT: In most studies, quantile estimates of extreme 24-hour rainfall are given in annual probabilities. The probability of experiencing an excessive storm event, however, differs throughout the year. As a result, this paper explored the differences between heavy rainfall distributions by season in Louisiana. It was concluded by using the Kruskal-Wallis and Mann-Whitney tests that the distribution of heavy rainfall events differs significantly between particular seasons at the sites near the Gulf Coast. Furthermore, seasonal frequency curves varied dramatically at the four sites examined. Mixed distributions within these data were not found to be problematic, but the mechanisms that produced the events were found to change seasonally. Extreme heavy rainfall events in winter and spring were primarily generated by frontal weather systems, while summer and fall events had high proportions of events produced by tropical disturbances and airmass (free-convective) conditions.  相似文献   
253.
254.
用灰色模型预测我国铁路水害发展趋势   总被引:2,自引:0,他引:2  
周华国  魏庆朝 《灾害学》1996,11(2):23-27
根据近15a来我国铁路水害年断道时间和断道次数的数据特点,将不同程度水害年分为三个等级。在此基础上,建立了铁路水害的灰色预测模型。并用此模型预测了近期铁路水害大小和远期的发展趋势。这对于我国铁路水害防治的宏观决策具有指导意义。  相似文献   
255.
A framework for transformation of knowledge and experience from risk analysis to emergency education is presented. An accident model was developed built on the concept “uncontrolled flow of energy (UFOE)”, where essential elements are the state, location and movement of the energy. A UFOE can be considered as the driving force of an accident, e.g. an explosion, a release of heavy gases. A domain model has been developed for representing emergencies occurring in society. A domain is a group of activities with allied goals and elements, and the domain model uses three main categories: status, context and objectives. Ten specific domains have been investigated including process plant, energy production and distribution, natural disasters and different sorts of transport. Totally 25 accident cases were consulted and information was extracted for filling into the schematic representations with two to four cases pr. specific domain.  相似文献   
256.
Car manufacturers must eliminate automotive shredder residues (ASR). Two ways of incineration are of interest: at 850°C in municipal waste incinerators or at higher temperatures, above 1100°C in cement plants. These processes reduce the mass and the volume of waste to be disposed of in landfills and energy recovery might be possible. Regulations govern the emission of gaseous effluents to control environmental risk. To determine gaseous effluents from a pilot sacle or an industrial incineration plant, an artificial ASR was made by mixing three representative organic polymers present in the real ASR, namely polyvinylchloride, polyurethane and rubber. This mixture was incinerated at 850 and 1100°C in laboratory experiments and the analyses of the principal gaseous effluents such as carbon oxides, nitrogen oxides, volatile organic compounds, hydrochloric and hydrocyanic acids and sulphur compounds are presented and discussed. Lastly, in order to simulate artificial ASR behaviour, the composition of the combustion gases at equilibrium was calculated using a Gibbs energy minimisation code.  相似文献   
257.
Groundwater was being remediated with pump and treat technology at a facility where the groundwater was contaminated with commonly used degreaser solvents. Hydraulic conductivity of the heterogeneous residuum was beneficiated by applying pneumatic fracturing technology. The remedial system was controlled and monitored by a sophisticated remote telemetry system. A case history follows.  相似文献   
258.
Relationships are fundamental to organizational functioning, yet as telecommuting and other forms of virtual work become increasingly popular, research has not yet focused on how the virtual context might alter relationships so as to impact important work outcomes. This study therefore examines the role relationships play in mediating the link between the extent of telecommuting and job satisfaction. In doing so three fundamental types of relationships maintained by employees are investigated—those with managers, coworkers, and family. Regression analysis of field data from 294 telecommuting employees in a large telecommunications company revealed the anticipated inverted U‐shaped relationship, mediated by leader‐member exchange quality, team‐member exchange quality, and work‐family conflict. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   
259.
This paper describes the results from a series of fire tests that were carried out to measure the effect of defects in thermal protection systems on fire engulfed propane pressure vessels.

In North America thermal protection is used to protect dangerous goods rail tank-cars from accidental fire impingement. They are designed so that a tank-car will not rupture for 100 min in a defined engulfing fire, or 30 min in a defined torching fire. One common system includes a 13 mm blanket of high-temperature ceramic fibre thermal insulation covered with a 3 mm steel jacket. Recent inspections have shown that some tanks have significant defects in these thermal protection systems. This work was done to establish what levels of defect are acceptable from a safety standpoint.

The tests were conducted using 1890 l (500 US gallon) ASME code propane pressure vessels (commonly called tanks in the propane industry). The defects tested covered 8% and 15% of the tank surface. The tanks were 25% engulfed in a fire that simulated a hydrocarbon pool fire with an effective blackbody temperature of 870 °C.

The fire testing showed that even relatively small defects can result in tank rupture if the defect area is engulfed in a severe fire, and the defect area is not wetted by liquid from the inside. A wall failure prediction technique based on uniaxial high-temperature stress rupture test data has been developed and agrees well with the observed failure times.  相似文献   

260.
从废感光胶片中回收银   总被引:2,自引:0,他引:2  
研究了以Fe3 -乙二胺四乙酸二钠-N a2S2O3体系为浸取剂从废感光胶片中回收银的方法,考察了浸出银的最佳工艺条件。实验表明,当浸取剂中FeC l3.6H2O质量浓度为35g/L、N a2S2O3.5H2O质量浓度为150g/L、pH为7、固液质量比为3∶10时,浸取剂可重复使用6次,胶片上银的浸出率可达99%以上;浸取液中的银采用硼氢化钠还原回收,粗银粉配以熔剂高温熔炼可得到纯度达99.78%的银,银回收率达96.88%,回收银后的浸取液可循环使用。  相似文献   
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