The role of the Federal Government in US marine transportation

The United States meets the world shipping crisis of the 1970s with a high-cost merchant fleet and a national maritime policy which needs clearer articulation. This paper examines the objectives, rationale and methods of implementation of the Us maritime programme with attention, finally, to the question of governmental reorganization.     

Impact of offshore oil and gas development on the coastal zone: Reforming the impact assessment process

In an otherwise complex regulatory system, the federal Environmental Impact Statement process affords local decision makers and coastal zone residents a rare opportunity to analyze the comprehensive range of land‐use and environmental issues that may arise from Offshore Continental Shelf (OCS) hydrocarbon development, while there is still time to formulate effective management strategies. As exemplified by the lease sale 40 statements, present onshore impact assessment procedures are sufficiently flawed to seriously compromise this goal. Critical deficiencies include failure to emphasize onshore impacts; insensitivity to spatial variations of impact; neglect of available data; rigid, unsupported assumptions; and preoccupation with short‐trm effects to the exclusion of more significant and dependent long‐term consequences. Suggested reforms include preparation of separate exploration and development impact statements; establishment of special Council on Environmental Quality review procedures; modification of the judicial review process; and provision of additional support to local onshore OCS impact areas.     

A Systematic method of public use zoning of the Great Barrier Reef Marine Park,Australia

Abstract

This paper is an abridged version of a report on the application of a land‐use planning method developed by the Commonwealth Scientific and Industrial Research Organisation (CSIRO) to the task of providing a zoning scheme for a portion of the Great Barrier Reef Marine Park. The approach involves the development of guidelines for making zoning decisions, the development of methods for measuring whether a scheme satisfies these guidelines, and the use of a computer‐aided technique to create successive schemes for evaluation against these guidelines.     

新开发的轮对设计方法

轮对设计在车轮磨耗方面正面临着严格的新规范 ,以降低外形车削的要求 ,并减轻质量 ,以减少对轨道的侵蚀 ,且在可靠性、运行安全性和寿命周期成本都没有不利影响的情况下 ,实现所有要求。与此同时 ,由于车辆有既在小半径曲线 ,又在高速线路上运行的趋向 ,在普通线路上提高了运行速度 ,以及由于低级维护而使线路质量和车辆质量有所降低 ,所以轮对的运行作用正在变化。为此 ,开发了一整套程序 ,以便为高速列车设计振动小、噪声低、寿命周期成本最佳的轮对 ,也为城市轨道车辆设计新型的使用铝制轮毂、钢制车轴和轮辋的轻型混合车轮。该程序以采…     

新型快餐盒生物降解性能试验方法研究

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。     

A “horizontal Sverdrup mechanism” may control the spring bloom around small oceanic islands and over banks

One of the most basic paradigms in marine ecology is the “Sverdrup mechanism,” where the spring bloom is retarded if the surface mixed layer is too deep, due to the algae being mixed vertically out of the euphotic layer. A similar mechanism may operate in vertically homogeneous water over a small shallow area, surrounded by deep waters, if the horizontal exchange is sufficiently intense. In systems with inter-annual variations in the horizontal exchange rate, this may induce inter-annual variations in the timing and intensity of the spring bloom. A numerical primary production model with circular symmetry and prescribed horizontal exchange rate is developed. Using the Faroe Shelf as an example, the model and observations show that the timing and intensity of the spring bloom in the shallow parts of the system may be critically dependent upon the rate of the horizontal exchange. Numerical experiments confirm that the effect of horizontal exchange on the spring bloom is less pronounced for banks than for shelf systems around islands of similar scales, and that the effect increases in importance as the horizontal scale is reduced.     

高速铁路车辆车轴的疲劳设计方法

从19世纪早期铁路运营开始,车轴的疲劳设计就是工程设计人员在材料的疲劳研究方面的一个难点。为了保证高速铁路系统的安全,一些杰出的研究人员进行了大量的投资和试验,并且在材料、制造、热处理和设计方法等方面取得了很大进步。比较欧洲和日本在高速铁路车辆车轴疲劳设计上的原理,认为在新干线车辆和TGV,ICE之间存在一些区别。疲劳强度的危险部位主要是容易受到磨损和疲劳损伤的压装配合部位,如轮座、齿轮座和制动盘座等部位。在欧洲,车轴压装部位采用大直径使危险部位平滑;在日本采用高频硬化的方法提高压装部位的疲劳强度,同时在车轴的压装部位附近设置了应力释放槽。多年来,新干线的车轴经过磁粉探伤没有发现疲劳磨损裂纹,这表明高速铁路车轴的安全性多年的改进是成功的。     

韩国HSR 350x型高速动车组的开发

韩国在引进法国TGV之后于2004年4月1日启动了韩国特快列车(KTX)的运营,从此韩国便开始步入了高速铁路时代,这被称为"内陆运输革命".此外,韩国通过名为"高速铁路技术开发"的国家研发项目,自主研制出350型高速试验动车组(HSR 350x),在2003年9月汉城至釜山高速试验线上运行时,其运行速度超过了300 km/h.HSR 350x作为最佳技术成果载入韩国铁路史.HSR 350x是韩国工程技术人员研制的,从概念设计到在线试验共用了6年的时间.按既定目标该动车组投入Honam高速线的商业运营以及在先期的运行中确定其与地面设施的兼容性.这样,韩国能充分利用自己的技术设计高速铁路、开发主要设备和生产动车组.也就是说,韩国通过修建汉城至釜山的高速铁路线,能进一步掌握高速铁路的建造、管理与维护技术.这一巨大成果将使韩国成为世界上拥有最佳高速铁路技术水平的国家之一.详细介绍了HSR 350x型高速动车组及其主要核心设备的开发.     

Primary productivity of the Palmer Long Term Ecological Research Area and the Southern Ocean

A major objective of the Palmer Long Term Ecological Research (Palmer LTER) project is to obtain a comprehensive understanding of the various components of the Antarctic marine ecosystem. Phytoplankton production plays a key role in this so-called high nutrient, low chlorophyll environment, and factors that regulate production include those that control cell growth (light, temperature, and nutrients) and those that control cell accumulation rate and hence population growth (water column stability, grazing, and sinking). Sea ice mediates several of these factors and frequently conditions the water column for a spring bloom which is characterized by a pulse of production restricted in both time and space. This study models the spatial and temporal variability of primary production within the Palmer LTER area west of the Antarctic Peninsula and discusses this production in the context of historical data for the Southern Ocean. Primary production for the Southern Ocean and the Palmer LTER area have been computed using both light-pigment production models [Smith, R.C., Bidigare, R.R., Prézelin, B.B., Baker, K.S., Brooks, J.M., 1987. Optical characterization of primary productivity across a coastal front. Mar. Biol. (96), 575–591; Bidigare, R.R., Smith, R.C., Baker, K.S., Marra, J., 1987. Oceanic primary production estimates from measurements of spectral irradiance and pigment concentrations. Global Biogeochem. Cycles (1), 171–186; Morel, A., Berthon, J.F., 1989. Surface pigments, algal biomass profiles and potential production of the euphotic layer—relationships reinvestigated in view of remote-sensing applications. Limnol. Oceanogr. (34), 1545–1562] and an ice edge production model [Nelson, D.M., Smith, W.O., 1986. Phytoplankton bloom dynamics of the western Ross Sea ice edge: II. Mesoscale cycling of nitrogen and silicon. Deep-Sea Res. (33), 1389–1412; Wilson, D.L., Smith, W.O., Nelson, D.M., 1986. Phytoplankton bloom dynamics of the Western Ross Sea ice edge: I. primary productivity and species-specific production. Deep-Sea Res., 33, 1375–1387; Smith, W.O., Nelson, D.M., 1986. Importance of ice edge phytoplankton production in the Southern Ocean. BioScience (36), 251–257]. Chlorophyll concentrations, total photosynthetically available radiation (PAR) and sea ice concentrations were derived from satellite data. These same parameters, in addition to hydrodynamic conditions, have also been determined from shipboard and Palmer Station observations during the LTER program. Model results are compared, sensitivity studies evaluated, and productivity of the Palmer LTER region is discussed in terms of its space time distribution, seasonal and interannual variability, and overall contribution to the marine ecology of the Southern Ocean.     

U.S. public transit earnings, employment and privatization

This paper uses individual worker and municipal information to examine privatization's influence on public transit workers' earnings and employment. OLS findings on labor earnings reveal that privatization is associated with an erosion of the public transit union premium. These labor earning findings do not change when correcting for privatization heterogeneity, as unobserved worker characteristics do not differ with differing levels of municipal privatization of public transit services. The employment findings reveal that union public transit workers are more likely to be employed in the public sector and this union-nonunion employment probability differential, declines with increasing levels of privatization. This employment result is interpreted as suggesting that labor cost savings from privatization can be derived from the enhanced employment of relatively low wage nonunion workers in the public sector of public transit services.