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1.
Brian J. Thomas 《Maritime Policy and Management》1995,22(3):239-253
Overmanning and restrictive labour practices are major causes of low productivity in Indian ports. Proposals are put forward for a programme of reforms to support investment in modern cargo handling systems. 相似文献
2.
This paper documents an application of panel, or longitudinal data collection in the evaluation of a TSM (Transportation Systems Management) demonstration project. The project was a four-week demonstration of staggered work hours in downtown Honolulu during February–March 1988. The 4 wave panel survey elicited commuting experiences of approximately 2,000 downtown employees at two week intervals before and during the project. The sample involved both employees who participated in the project by shifting their work hours, and those who did not. The panel survey was augmented by floating-car observations of travel times on major routes into downtown Honolulu on the same four dates.The purpose of the analysis was to determine whether employee commute times were affected, and if so, how these changes were distributed among various employee segments. Two methods were used. First, travel time changes were estimated using paired t-tests. Second, regression equations were used to estimate project time savings as a function of trip length, route, and location of residence. Results show that travel time savings due to the project were typically small, less than ten percent. Nonparticipants experienced greater savings than participants, and some segments of participants experienced longer travel times during the project. The panel method proved to be an effective way to measure project travel time impacts and shows that the method is appropriate in short time applications.Presented at the Annual Meeting of Transportation Research Board, January 7–11. 1990, Washington, D.C. 相似文献
3.
基板与陶瓷衬底之间的焊层寿命通常利用IGBT模块的被动加热和冷却(热循环)来测试,但这种试验会引起焊层失效(分层)。实际应用中,IGBT和二极管芯片是主动被加热的,诸如焊线脱落等其它模式的失效也会限制使用寿命,通常可通过功率循环试验来评估这种应力的影响。本文通过功率循环试验来评估衬底焊层的失效,利用高循环周次的测试进行有效的衬底焊层热循环试验,其关键在于功率循环过程中焊层温度的预测。在温度波动不大的条件下,比较了被动热循环和主动功率循环时对焊接寿命的影响。 相似文献
4.
5.
在介绍电磁缓速制动器工作原理的基础上,通过电磁理论推导,得到了电磁缓速制动器制动功率和制动力矩的计算公式,并研究了温度升高对电磁缓速制动器主要参数电导率和相对磁导率的影响。 相似文献
6.
Newell Garfield Mathew E. Maltrud Curtis A. Collins Thomas A. Rago Robert G. Paquette 《Journal of Marine Systems》2001,29(1-4)
During the period 1992–1998, 38 isobaric RAFOS floats were deployed to sample the subsurface flow of the California Undercurrent. The deployments, released over the California continental slope west of San Francisco, have sampled robust year-round poleward subsurface flow associated with the Undercurrent most seasons and the combined inshore current and Undercurrent in winter. Two other types of flow have been seen: a region of weak flow with little net displacement just west of the California Undercurrent, and an active westward propagating eddy field. This eddy field appears to be the primary mechanism for moving floats from the Undercurrent into the ocean interior. The observations and statistics from the RAFOS floats are compared with Lagrangian estimates of particles tracked in a global high resolution ocean simulation in order to evaluate the fidelity of the model along an eastern boundary. The results show that the model reproduces the general character of the flow reasonably well, but underestimates both the mean and eddy energies by a substantial amount. 相似文献
7.
Dagmar Hainbucher Wei Hao Thomas Pohlmann Jürgen Sündermann Shizuo Feng 《Journal of Marine Systems》2004,44(3-4):153
The circulation and the hydrography of the Bohai Sea are simulated with the Hamburg Shelf Ocean Model (HAMSOM). The model is three-dimensional, prognostic baroclinic and has a resolution of 5 min in latitude and longitude and 10 layers in the vertical. It is initialised and forced with the five main tidal constituents, temperature and salinity distributions taken from the Levitus database, monthly mean river run-off values and European Centre for Medium Range Weather Forecast (ECMWF) re-analysed data of air pressure, wind stress and of those parameters relevant for the calculation of heat fluxes. The simulation period covers 14 years from 1980 to 1993 due to the availability of the time-dependent ECMWF forcing.The results are analysed by means of time series and EOFs focussing on the interpretation of fluctuations with periods above the tidal cycle. Furthermore, tracer simulations are carried out and turnover times are calculated in order to evaluate the importance of these fluctuations on the renewal and transport of water masses in the Bohai Sea.One of the major outcomes of the investigation is the overall dominance of the annual cycle in all hydrographic parameters and the importance of stochastic weather fluctuations on the transport of water masses in the Bohai Sea. 相似文献
8.
This paper described the process of generating the optimal parametric hull shape with a fully parametric modeling method for three containerships of different s... 相似文献
9.
HAMADE Thomas A. 《上海交通大学学报(英文版)》2018,(1)
High voltage electrostatics and corona discharge are utilized for various applications in pollution and environmental control. The traditional applications have many flaws due to improper construction of electrode design and assembly that cause system failure, in particular when electrically stimulated devices are exposed to high humidity. A new innovative-patented design by Hamade, electrically stimulated catalytic converter(ESCC),eliminates such flaws and shows the wide practical applications of the new design. The new design utilized previous patented designs and work of the same inventor but retrofitted for catalytic auto exhaust emission control. The current and previous patents include: employing electrically stimulated filtration(ESF) to replace high efficiency particulate air(HEPA) filters, treatment of biological and infectious diseases, electret fabrication, and, most notably, the invention of a new electrically stimulated catalytic converter(ESCC). The electrically stimulated catalytic converter invention includes an exhaust conduit fed from the engine exhaust port with a housed corona charger apparatus. The opposite end is opened to the atmosphere outside of the vehicle or connected to a reduced-size catalytic converter. The corona charger is intrusively or non-intrusively associated with a main flow path defined by the exhaust conduit. The corona charger includes at least one electrode, which may be recessed away from, the main flow path. A plurality of corona chargers may be used in various combinations, optimally a two dimensional grid. The electrically stimulated catalytic converter is adapted to treat and eliminate auto exhaust pollution emission to air. 相似文献
10.
Brian J. Thomas 《Maritime Policy and Management》2013,40(3):239-240
Overmanning and restrictive labour practices are major causes of low productivity in Indian ports. Proposals are put forward for a programme of reforms to support investment in modern cargo handling systems. 相似文献