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991.
992.
R. L. Shogren 《Journal of Polymers and the Environment》1995,3(2):75-80
Granular cornstarch was coated with several biodegradable polymers in an effort to improve the mechanical properties of starch-poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) composites. Only samples containing poly(ethylene oxide) (PEO)-coated granular starch showed a large improvement in tensile properties over uncoated starch. For example, a 50/50 blend of PEO-coated starch and PHBV had a tensile strength of 19 MPa and an ultimate elongation of 23%, compared to 10 MPa and 11% for a similar blend containing uncoated starch. PEO may act as an adhesive between the starch and the PHBV and/or increase the toughness and resistance to crack growth of PHBV around the starch granules.Paper presented at the Bio/Environmentally Degradable Polymer Society—Third National Meeting, June 6–8, 1994, Boston, Massachusetts.Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product and the use of the name by the USDA implies no approval of the product to the exclusion of others that may also be suitable. 相似文献
993.
Twenty-five years of HAZOPs 总被引:7,自引:0,他引:7
The HAZOP or hazard and operability study was developed by ICI over 25 years ago and is in wide use today throughout the world. The technique is intended to review, in a formalized manner, the design of a system such as a chemical process production plant to detect potential problems in the operation of the system. The system has been extended for use on all types of production, storage and distribution units. Experience in the use of hazard studies has lead to the development of a phased approach with three distinct design phases. 相似文献
994.
The complexity of the study and reconstruction of traffic accidents justifies the creation of tools which make easier the research in this area. That is the reason why the GIVET has developed a program called SINRAT III that lets, by means of dynamic simulation, reproduce the evolution of two vehicles in an accident in which a collision takes place, letting analyze the precollision and postcollision movements, as well as studying what happens during the contact and deformation of the vehicles in the collision stage. The simulation model is integrated by bodies developed using the bond-graph technique, that allows the simulation of the dynamic behaviour of the vehicles in any circumstance. At the end of this paper, an application example is presented, corresponding to an accident with collision between car and coach. 相似文献
995.
The effect of environmental and design parameters on subjective road safety — a case study in Poland
L. Zakowska 《Safety Science》1995,19(2-3)
In order to get a better insight into the safety effects of alternative road designs, the subjective safety experiment has been conducted. The experiment has been designed to test the effect of geometric design characteristics and road environment on the subjective safety of rural road curves. The method used here allows to investigate the effect of a real driving environment on safety in a complex way. The results have shown the importance of the composed effect of curve geometry and curve environment on the subjective safety of rural curves. 相似文献
996.
Martha L. Crouch 《Journal of Agricultural and Environmental Ethics》1995,8(2):98-111
Biotechnology increases commercialization of food production, which competes with food for home use. Most people in the world grow their own food, and are more secure without the mediation of the market. To the extent that biotechnology enhances market competitiveness, world food security will decrease. This instability will result in a greater gap between rich and poor, increasing poverty of women and children, less ability and incentive to protect the environment, and greater need for militarization to maintain order. Therefore, biotechnology should be discouraged. An active program to protect and strengthen local food production and to decrease reliance on industrial agriculture should be promoted. 相似文献
997.
The National Forest Management Act (1976) specifies that multiresource inventories be conducted to provide baseline data for
development and, later, monitoring of national forest management plans. This mandate entails the most ambitious and complex
resource planning effort ever attempted. In this paper we evaluate the structure and use of current inventory-monitoring programs
and recommend a framework for gathering data to improve national forest planning. Current national guidelines are general
and provide only basic directions to forest-level planners. Forest inventories have traditionally concentrated on timber.
Although these inventories are often well designed, the questions we are now asking about forest resources have outgrown these
methods. Forest management is impeded by general confusion over definitions of resources and the interactions among them.
We outline a simple classification scheme that centers on identification of basic ecosystem elements that can be readily measured.
Furthermore, spatial and temporal scales must be considered in the design of inventory-monitoring programs. The concept of
ecological indicators is reviewed, and caution is advised in their use. Inventory-monitoring programs should be goal-directed
and based on as rigorous a statistical design as possible. We also review fundamental issues of variable selection, validation,
and sampling bias. We conclude by developing a flexible inventory-monitoring program that is designed to provide information
on individual characteristics of the environment, rather than being based on fixed definitions of resources. 相似文献
998.
Some studies have been done dealing with cattle manure treatment, but literature scarcely reports the use of immobilized microalgae as final treatment of this waste. Recently, a complete technology for cattle manure treatment was established, including immobilized microalgae. The influence of the recirculation in the efficiency of the immobilized microalgae process was evaluated. 相似文献
999.
Richard S. Krannich Sean P. Keenan Michael S. Walker Donald L. Hardesty 《Journal of the American Water Resources Association》1995,31(5):851-865
ABSTRACT: Survey data collected in the San Joaquin Valley of southern California and the Grand Valley of western Colorado reveal that residents of both areas believe that a severe sustained drought is likely to occur within the next 20–25 years and that their communities would be seriously impacted by such an event. Although a severe sustained drought affecting the Colorado River Basin would cause major economic and social disruptions in these and other communities, residents express little support for water management alternatives that would require significant shifts in economic development activities or in water use and allocation patterns. In particular, residents of these areas express little support for strategies such as construction and growth moratoriums, mandatory water conservation programs, water transfers from low-to high-population areas, water marketing, or reallocations of water from agricultural to municipal/industrial uses. This rejection of water management strategies that would require a departure from “business as usual” with respect to water use and allocations severely restricts the capacity of these and similar communities to respond effectively should a severe sustained drought occur. 相似文献
1000.
Taiye B. Sangoyomi Benjamin L. Harding 《Journal of the American Water Resources Association》1995,31(5):925-938
ABSTRACT: We evaluated the effects of institutional responses developed for coping with a severe sustained drought (SSD) in the Colorado River Basin on selected system variables using a SSD inflow hydrology derived from the drought which occurred in the Colorado River basin from 1579–1616. Institutional responses considered are reverse equalization, salinity reduction, minimum flow requirements, and temporary suspension of the delivery obligation of the Colorado River Compact. Selected system variables (reservoir contents, streamflows, consumptive uses, salinity, and power generation) from scenarios incorporating the drought-coping responses were compared to those from Baseline conditions using the current operating criteria. The coping responses successfully mitigated some impacts of the SSD on consumptive uses in the Upper Basin with only slight impacts on consumptive uses in the Lower Basin, and successfully maintained specified minimum streamflows throughout the drought with no apparent effect on consumptive uses. The impacts of the coping responses on other system variables were not as clear cut. We also assessed the effects of the drought-coping responses to normal and wet hydrologic conditions to determine if they were overly conservative. The results show that the rules would have inconsequential effects on the system during normal and wet years. 相似文献