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831.
Liability is an important incentive‐based instrument for preventing oil spills and provides a sustainable approach for restoring coastal resources injured by spills. However, the use of liability for environmental damages raises many challenges, including quantification of money measures of damages. In this article, case studies are used to illustrate the issues, methods, and challenges associated with assessing a range of damages, from those that can be measured relatively easily using market information to more “esoteric,”; and much more difficult, cases involving non‐market‐valued losses. Also discussed are issues raised by the new national and international regulatory focus on restoration and by the simplified, compensatory formula used by some states.  相似文献   
832.
Levels of the heavy metals Copper (Cu), Zinc (Zn), Lead (Pb), Cadmium (Cd), Chromium (Cr), Nickel (Ni), Iron (Fe) and Manganese (Mn) were determined in coastal water, sediments and soft tissues of the gastropod limpet, Patella caerulea, and the bivalve, Barbatus barbatus, from seven different stations in the western coast of the Gulf of Suez. The concentrations of heavy metals in water ranged between 3.37–4.78, 18.83–21.46, 2.75–3.17, 0.22–0.27, 0.99–1.21, 2.69–3.65, 3.75–4.56 μg L− 1 and 23.82–32.78 mg g− 1 for Cu, Zn, Pb, Cd, Cr, Ni, Mn and Fe, respectively. The corresponding concentration values in the sediments were 8.65–12.16, 51.78–58.06, 36.52–42.15, 3.23–3.98, 9.03–12.75, 34.31–49.63, 3.28–4.56 and 64.20–70.22 μg g− 1 for Cu, Zn, Pb, Cd, Cr, Ni, Mn and Fe, respectively. The highest accumulated metals were Fe, Zn and Mn in both P. caerulea and B. barbatus, while the lowest one was Cd. The accumulation of metals was more pronounced in P. caerulea than B. barbatus. The highest concentrations of all metals in water, sediments and mollusca were recorded at Adabiya harbour north of the Gulf, while the lowest concentrations were recorded at Gabal El-Zeit and Hurghada. Land based activities and ships awaiting berth are the main source of metal pollution in the northern part of the Gulf.  相似文献   
833.
软基处理新方法--IFCO强制固结法及其固结度求解   总被引:1,自引:0,他引:1  
针对IFCO强制固结法,基于对砂墙地基应力状态的分析,建立其固结度的解答方法。在此基础上,探讨砂墙的涂抹作用和土体的双向渗流对地基固结效果的影响,以期对工程实践有指导意义。  相似文献   
834.
The setation patterns of female antennules of some Paracyclops species are analysed with reference to the hypothetical 28-segmented antennule of ancestral copepod proposed by Huys and Boxshall in 1991. Comparison between Paracyclops species has revealed a setation pattern common to all species thus far examined. Several modifications of the female antennules have been identified as apomorphic states and can be used in phylogenetic studies. P. waiariki has 12-segmented antennules and exhibits more plesiomorphic characters than the reduced 8-segmented antennules of other species, such as P. fimbriatus. The results confirm that simple segment numbers are unusable as characters in cladistic analysis. Both P. affinis and P. yeatmani, for example, have 11-segmented antennules but analysis of segmental homologies has revealed that the 11-segmented state is convergent in these two species.  相似文献   
835.
The results of a study on the spatial and temporal dynamics of size-fractionated biomass and production of phytoplankton in the Ross Sea during the austral spring and summer are reported. The spring cruise took place in the offshore Ross Sea from 14 November to 14 December 1994. Sampling was carried out on a transect of 27 stations distributed from 76.5 to 72.0°S along 175°E, and covered the three main Antarctic environments of the polynya open waters, the marginal ice zone and the pack ice area. Three subsystems were identified. The subsystem of the polynya was characterised by the predominance of the micro- and nano-planktonic fractions, chlorophyll (Chl a) concentrations from 69.6 to 164.7 mg m−2 and production rates from 0.68 to 1.14 g C m−2 day−1. The second subsystem, the marginal ice zone, showed a relative increase of the micro-planktonic fraction, high biomass levels (from 99.64 to 220 mg Chl m−2) and production rates from 0.99 to 2.7 g C m−2 day−1. The subsystem of the pack ice area had a phytoplankton community dominated by the pico-planktonic fraction and showed low biomasses (from 19.4 to 37.7 mg Chl m−2) and production rates (0.28 to 0.60 g C m−2 day−1). Selective grazing by krill is considered an important factor in determining the size structure of the phytoplankton communities. The summer study consisted of a time series carried out in inshore waters of Terra Nova Bay from 12 January to 8 February 1990. In a well stabilised water column and with high levels of PAR always available, the primary production rates of a community dominated by micro-plankton varied from 0.52 to 1.2 g C m−2 day−1 (average 0.84). A high P/B ratio, up to 3, and a remarkably elevated mean phaeopigment (Phaeo)/Chl a ratio of 2.4 indicated an active removal of biomass by grazing, confirmed by the presence of faecal pellets in quantities reaching 6000 m−3 in the upper 50 m. The peculiarities of the inshore versus offshore environments in terms of community size structure, production processes and their implications as regards the food web are discussed.  相似文献   
836.
目前,机务段用以测定机车轮对轮箍磨损的检测工具一般都为机械检测工具,例如量规和卡规等等.为了对轮对的滚动面(踏面)作有效而精确的检测,国立乌拉尔交通学院与传感器信息工艺学院的专家们研制出了1种新的仪表.  相似文献   
837.
新型快餐盒生物降解性能试验方法研究   总被引:1,自引:0,他引:1  
通过固体培养微生物侵蚀试验、液体培养微生物侵蚀试验、降解过程中纤维素酶活性测定、纤维素酶侵蚀试验和降解过程中 C O2 生成体积分数的测定等试验结果分析,认为固体培养微生物侵蚀试验、纤维素酶侵蚀试验及 C O2 生成量测定试验可用于评价新型快餐盒生物降解性能。  相似文献   
838.
Due to requirements related to computational efficiency, in the majority of railway dynamic simulators the Hertz theory is used for solving the normal problem in wheel/rail contact. This theory is based on a large number of assumptions. Particularly noteworthy is the assumed simplification that the undeformed distance between the bodies in contact can be assimilated by a quadratic function. There are many situations in which the undeformed distance cannot be represented by this kind of function. As such, the results obtained with Hertz theory in these cases are not accurate.

In this paper, a new method for solving the normal problem that overcomes the above-mentioned limitation is presented. First, the exactness of the new method is tested with Hertzian cases. The results obtained are almost exact. Second, the results calculated with the new method in more general cases are compared with the ones obtained with the variational method of Kalker (more exact but computationally less efficient).  相似文献   
839.
Summary In this paper we examine a linear one-degree of freedom vibration isolator mount. The linearity of the system allows us to analyze its frequency and time response characteristics analytically. Optimal damping and stiffness values for the isolator are obtained by minimizing certain cost functions, which are the Root Mean Square (RMS) of the absolute acceleration and the relative displacement. These RMS cost functions are used to create a design chart for the isolator parameters. This is very useful particularly in the presence of physical constraints such as a limit in relative displacement. The time response of the system for a unit step input is also considered to gain an insight into the transient characteristics of the system. We obtain an optimal value for the damping ratio of the system in order to minimize the transmitted acceleration. Combining the frequency and time response analyses leads to an optimal value for the mount natural frequency and damping ratio satisfying both time and frequency domains. The results are verified numerically using measured acceleration as input.  相似文献   
840.
Transportation planners and policy analysts require, for scenario testing, a detailed fuel consumption model of public transit operating in multimodal corridors. Although much effort has been devoted to the development of detailed methodology for estimating fuel consumption of automobile travel on freeways and arterials, the same is not the case for public transit. This paper presents methodology for the estimation of fuel consumption for bus operation on transitways/busways serving major travel corridors. Bus fuel consumption model is reported for standard and articulated buses. This model was adapted from an existing heavy vehicle fuel use model by incorporating the transitway design and bus operational characteristics.  相似文献   
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