Obsolete Maps and Coastal Management: Case Studies from Northwest Ireland

On dynamic coastal sites, subject to rapid and sometimes unpredictable shoreline changes, management problems can be aggravated if legally authoritative maps are obsolete. These difficulties are illustrated by two case studies from County Donegal in northwest Ireland. The first case study outlines the problems that arise where statutory functional area boundaries are based on a near century-old map. The second case study deals with the problems of planning development on a site where a customized map only a few years old has been rendered obsolete by rapid coastal erosion. Other problems are caused by the inappropriate use of maps. Suggestions are made to mitigate the effects of outdated maps.     

使用有限元分析以改善重载运输车轴

分析了北美铁路货运发生的车轴故障,介绍了使用有限元对F级和K级车轴进行应力分析计算,研究车轴尺寸变化对应力的影响,并提出了改善重载车轴设计的建议.     

王者归来

正后轮转向、减振器液压缓冲块、拖拽臂后悬架,雷诺运动/赛车部门Renault Sport推出的新一代Megane RS为钢炮提供了另外一种存在方式。这一次,本田Civic Type-R可得小心点了2017年法兰克福车展前几个月,雷诺运动/赛车部门Renault Sport把一小组记者召集到它藏在巴黎市郊、门面不大的总部所在地。记得Renault Sport的老板Patrice Ratti自信而且轻松地介绍着全新的Megane RS,那时离Megane RS的发布还有几个月,因此所有与会者都激动地盯着这台车,现场弥漫着一种诡异的紧张气氛。因为所有人     

US Navy Studies on Alternative Fuel Sources and Power and Propulsion Methods for Surface Combatants and Amphibious Warfare Ships

The US Navy has been studying the technical and cost impacts associated with the availability and cost of fossil fuel contrasted with nuclear energy alternatives for surface combatants and amphibious warfare ships. Over the past 2 years these efforts have grown in maturity to examine the tactical and strategic implications of our Navy's dependence on fossil fuels from technical, economic, and military perspectives. This paper will present three major topics:

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  Background research on alternative energy sources.
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  A survey discussion of current and future power and propulsion system technologies.
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  An overview of principal Naval Sea Systems Command studies on the integration of alternative power and propulsion system technologies into notional surface combatants, submarines, and amphibious warfare ships.

Given the US Navy's dependence on fossil fuels and the expected increase in cost and reduced availability of fossil fuel, propulsion system investment decisions made today will have a profound impact on the future tactical and strategic roles of the US Navy surface fleet. This paper lays the foundation for providing robust and flexible technology decision opportunities for the Navy's future.     

Importance of Addressing Human Systems Integration Issues Early in the Science and Technology Process

Historically, human systems integration (HSI) and other operational issues are not addressed during the science and technology (S&T) phase because the focus is on technology development. That view is to solve the "tough science" first, and the rest is simple application by a program office or operational forces. An imbalance between technology development efforts and total system performance considerations, e.g., total ownership cost, workload, manning, training, operational concept, skills, and human performance, leads to suboptimal solutions at best, and at worst prevents the technology's benefits from transitioning out of S&T at all. If HSI is not addressed during the S&T phase, the responsibility falls to the acquisition programs to ensure that operator, maintainer, and total system performance are optimized in the final design. By this point, cost and schedule constraints can make this prohibitive, limiting the options to either using a legacy system or accepting the technology with suboptimal performance and high life-cycle costs (because design problems lead to manpower, training, and human error problems). However, if the S&T community uses HSI in their technology readiness level evaluation criteria, the Department of Defense can reduce its out-year costs and recapitalize that funding to buy required weapons systems and platforms while still reaping the tactical benefits that a new technology offers.     

Improvement of Propeller Hydrodynamic Drag and Efficiency on USCG Cutters Operating in Trailshaft Mode

Large US Coast Guard cutters spend much of their underway time with only one of two propellers operating. The offline propeller is "trailed," often creating a significant amount of hydrodynamic drag. Operators from the fleet do not appear to have any specific guidance on how best to reduce this drag. Using the propeller analysis tools PSF-3 and PSF-10, propeller thrust coefficient values versus advance coefficient values were created for the propellers of the USCG 270' cutters. These values—and the associated drag—vary significantly in magnitude based on the trailed propeller pitch. Based upon sea trial measurements, expected magnitudes of this drag versus pitch setting were predicted. Minimum drag pitch settings were identified for an operational 270' cutter at 8 knots. RPM and pitch settings for maximum hydrodynamic efficiency for the online shaft are sometimes developed during ship acquisition. In the current work, a methodology for conducting such a study is discussed to demonstrate to ship operators the relative ease with which they could perform this analysis on board, if effective power and propeller thrust coefficient values are available. Consideration of prime mover specific fuel consumption rates together with propeller hydrodynamic efficiencies is discussed.     

Vulnerability of Port and Harbor Communities to Earthquake and Tsunami Hazards: The Use of GIS in Community Hazard Planning

Earthquakes and tsunamis pose significant threats to Pacific Northwest coastal port and harbor communities. Developing holistic mitigation and preparedness strategies to reduce the potential for loss of life and property damage requires community-wide vulnerability assessments that transcend traditional site-specific analyses. The ability of a geographic information system (GIS) to integrate natural, socioeconomic, and hazards information makes it an ideal assessment tool to support community hazard planning efforts. This article summarizes how GIS was used to assess the vulnerability of an Oregon port and harbor community to earthquake and tsunami hazards, as part of a larger risk-reduction planning initiative. The primary purposes of the GIS were to highlight community vulnerability issues and to identify areas that both are susceptible to hazards and contain valued port and harbor community resources. Results of the GIS analyses can help decision makers with limited mitigation resources set priorities for increasing community resiliency to natural hazards.     

Comparison of car ownership models

Car ownership models found in the academic literature (with a focus on the recent literature and on models developed for transport planning) are classified into a number of model types. The different model types are compared on a number of criteria: inclusion of demand and supply side of the car market, level of aggregation, dynamic or static model, long‐ or short‐run forecasts, theoretical background, inclusion of car use, data requirements, treatment of business cars, car‐type segmentation, inclusion of income, of fixed and/or variable car cost, of car quality aspects, of licence holding, of sociodemographic variables and of attitudinal variables, and treatment of scrappage.     

September 11 and the World Airline Financial Crisis

Abstract

This paper analyses the effectiveness of policy measures aimed at triggering a modal shift in the freight transport market. The analysis is based on the inventory‐theoretic framework that studies modal choice from a business logistics viewpoint. The crux of the inventory‐theoretic approach lies in the fact that explicit attention is paid to all costs in the supply chain that are affected by the choice of transport mode. After a brief literature review on the inventory‐theoretic framework, the framework is used to calculate the market shares of different freight transport modes for a hypothetical transport market. In a second step, the impact of some policy measures on the market shares of the transport modes is calculated. By way of illustration, the analysis is applied to the market for container transport from a seaport to its hinterland. It is shown that a combination of certain policy measures can lead to significant modal shifts from road transport to intermodal transport.     

Shipboard Fluid System Diagnostic Indicators Using Non-Intrusive Load Monitoring

Field studies have demonstrated that it is possible to evaluate the state of many shipboard systems by analyzing the electrical power that is drawn by electromechanical actuators. This paper demonstrates how a device known as a non-intrusive load monitor (NILM) uses only electrical power data to detect several critical faults in shipboard fluid systems. Using the example of reverse-osmosis units installed aboard the US Coast Guard's Medium Endurance Cutters, it is shown that the NILM can provide ship's force with a highly reliable real-time system monitoring capability.