Abyssal seafloor waste isolation: the concept

The Naval Research Laboratory (NRL), with industry and university participation, conducted an assessment of the concept of isolating certain wastes (i.e., sewage sludge, fly ash from municipal incinerators, and contaminated dredged material) on the oceans' abyssal seafloor. In this assessment the advantages, disadvantages, and economic and environmental viability of potential engineering methods for achieving abyssal waste isolation were identified and compared. This paper presents background to the Abyssal Plains Waste Isolation (APWI) Project, describes the characteristics of the waste streams and quantities potentially available for disposal via the abyssal isolation concept, summarizes regulations affecting use of the abyssal seafloor for disposal of wastes, and introduces the technical and scientific premises underlying implementation of the concept.     

Comment: Tankers' modification economics: Is there an arbitrage?

In this paper we address the following question: how much is a ship-owner willing to pay in order to convert his single-hull vessel to a double-hull vessel? Our research is motivated by a recent article in Tradewinds, according to which owners have become reluctant in scrapping their vessels by turning them into double hull from single hull. We apply a structural no-arbitrage condition for deriving and estimating 'good-deal' bounds.     

旭光大桥的加固改造研究

双曲拱桥是一种具有民族特色的拱桥型式,至今为止,在役的双曲拱桥营运时间约有30～40年的历史,双曲拱桥的加固改造已是迫在眉睫。通过旭光大桥的病害特点和原因进行分析,阐述了其加固改造的具体措施,材料要求,施工工艺等。实践证明：此法具有施工简单,速度快,质量好,造价低的优点,说明该桥的加固改造是成功的。     

Public transport policy for central-city travel in the light of recent experiences of congestion charging

Excellent public transport which makes the private car a minority mode of central-city travel is a necessary condition for a political process towards the introduction of congestion charges. However, the charging system costs in London and Stockholm have proved to be unexpectedly high. Therefore, before these costs come down to an affordable level, zero-fares for central-city travel and stricter parking policy would be a first-best combination in many cities, always provided that the public transport is really competitive. A bold venture in public transport development is consequently the top priority irrespective of the transport pricing policy direction.     

日本磁悬浮列车

介绍了日本低温超导磁悬浮列车推进、悬浮、导向的有关原理和实现方式,并概述了山梨试验线和相关的投资情况.     

The onset of biological winter in the eastern Weddell Gyre (Antarctica) planktonic community

Data on hydrography, phyto- and zooplankton, obtained on a transect along the 0° meridian during the Winter Weddell Gyre Study, June 1992, revealed peculiarities of the early winter situation in the eastern Weddell Gyre. The vertical distribution and developmental stage composition of Rhincalanus gigas, Calanoides acutus, Calanus propinquus and krill, Euphausia superba larvae, were a good index for a general assessment of the seasonal condition of the plankton communities. There were five zones differing in seasonal situation: (1) The Polar Front and the southern ACC (not studied in detail), (2) The Weddell Front, (3) The Weddell Gyre interior, (4) The Maud Rise area, and (5) The Coastal Current zone. In the Weddell Front, the planktonic community resembled an autumnal situation with moderate phytoplankton biomass; the overwintering stock of copepods was not completely formed and the occurrence of calyptopes larvae of E. superba indicated that krill continued to reproduce until May. In the Weddell Gyre interior, a typical winter plankton community was found even before sea ice had formed. The specific hydrographic regime of the Maud Rise (governed by the mesoscale circulation over the seamount) support the late autumn conditions similar to the Weddell Front (but without early krill larvae). The plankton of the Coastal Current was a winter community. We conclude that in the eastern part of the Weddell Front (compared to the western part) seasonal development of both phytoplankton and herbivorous zooplankton is delayed in spring but prolonged in late autumn. Furthermore, it appears that the Weddell Sea ecosystem exhibits a much higher degree of spatial and temporal variability than thought before. This may have an impact on seasonal pattern of organic carbon transport from the pelagic realm to deeper water layers and to the sediment.     

电喇叭振动疲劳分析

通过振动疲劳试验规范得到功率谱密度数据,以此作为输入,利用频响分析和疲劳分析等CAE分析方法,对该车型电喇叭及其支架在试验功率谱谱作用下的振动疲劳寿命进行分析计算,同时与试验结果进行对比。