Computer Simulation of Thermal-Mechanical Processing

AlterationIntroductionThereisastrongini6ractionamongtemPetalrefield,strCssfield,andmicrosttuctutulaltOrationinm8terialsduringtheirhotworking[l'2].Especiallyduringthecoolingprocess,inwhichtemPeratorechangnsgreatly,intendionsbecomemorecomplexbecauseoftransformationoccurmnce.Duringthehotdeformation,thingswillaPpearsuchas:a.hotdeformation,relatedtostressfieId,changesessentiallytheshaPeofmaterialsandcausesthevariationofthecontactstatebetWeenthedieandsample,resultinginchangeofthethermalboundnyco…     

高等海事院校学生学习动机初探

近年来在国际航运市场高度竞争趋势下,高等海事教育便成为船员素质养成的重要关键,在现今教育学习多元化的感染下,以学生为主体的学习活动,可增进学生主动探索知识、发现与解决问题,随之激发学生的潜能.本文以学习者本身、教师、学校三大构面来探讨学生学习动机构成因素,并依据学习动机理论结合相关专家学者的实务性教学意见,提出六项激励学习动机的教学策略,以教与学并进的方式规划与培养具有国际竞争能力的高级航海技术人员.在此,学生学习动机将扮演其正向积极的意义与功能.     

Spatial distribution of cadmium over a cyclonic eddy in the southern East China Sea

Eddy systems are a unique ecosystem, usually having high biological masses and primary production in the sea. In this study, both particulate and dissolved phases of cadmium in the water column of 15 stations over a cyclonic eddy in the southern East China Sea were determined to obtain their spatial distributions. This allows us to confirm that cyclonic eddy systems play the role of a Cd pump in the sea.Results showed that particulate Cd (PCd) and dissolved Cd (DCd) concentrations in water varied greatly, ranging over two orders and one order of magnitude, respectively. Large spatial variability was found not only for PCd but also for DCd in the upper water, apparently due to the effects of the cyclonic eddy system on the Cd distributions over the study area. DCd accounts for about 99% of the total Cd. For the surface water, DCd concentration at the eddy center was about five times the average of the water surrounding the eddy center. The depth distributions of DCd exhibited a typical surface depletion and a subsequent increase with depth; however, the PCd distribution showed the opposite, i.e. a surface maximum and a subsequent decline with depth. In general, the DCd maxima were found at depths of 600–1000 m, agreeing well with the literature. It reflected the internal biogeochemical cycling of Cd in the water column, which was driven by the utilization of Cd by plankton in the euphotic zone and by the regeneration of Cd at depth. In addition, a remarkably high DCd concentration existed in near-bottom water around the cyclonic eddy center.The horizontal distributions of both PCd and DCd in the upper water shared a common feature with elevated concentrations centering around the eddy center and a decline in concentration with distance from the eddy center. This shows that the cyclonic eddy could bring up the Cd-rich deep water to the surface water around the eddy center and could then expand toward eddy's vicinity via advection–diffusion. It is thus likely that it produces ample biological masses over the eddy system. Hence, this work can demonstrate that the ascending nutrient-rich water driven by the cyclonic eddies can serve as an important source not only for many nutrients but also for Cd in the sea.     

Introduction to the special issue on maritime security

The terrorist attacks of 11 September 2001 heightened awareness about the vulnerability of all modes of transportation to terrorist attack. The issue of maritime security has therefore become a major concern in the international maritime sector over the past several years. Globalization has led to a strong growth in seaborne trade; however, it simultaneously increases vulnerability to not only terrorism but also international criminal activities that threaten the world's supply chain. For example, in 2008, the rise in piracy activities in the Gulf of Aden brought the issue of maritime security to the forefront of international debate. In addition to the direct impact on ships, crews and cargoes, and on the maritime industry and governments, piracy also threatens global seaborne trade, and has an impact on energy security and the environment [UNCTAD, 2009, Review of Maritime Transport 2009 (New York: United Nations)]. Maritime piracy can pose substantial risks to seaborne trades, with considerable commodities, ranging between raw materials and energy to high-value manufactured products, being shipped between global economic powerhouses [FU, X. W., NG, A. K. Y., LAU, Y. Y., forthcoming, The impacts of maritime piracy on global economic development: The case of Somalia. Maritime Policy and Management]. Maritime security management, including the definition of security, maritime risk assessment, security measures, the regulation and policy of maritime security in shipping and port-related business operations has been receiving growing attention, both in practice and research.     

Evaluating the service requirements of dedicated container terminals: a revised IPA model with fuzzy AHP

The purpose of this article is to evaluate the service requirements of dedicated container terminals (DCTs). In this article, the service attributes (SAs) of DCTs were first discussed. A fuzzy analytic hierarchy process model was then constructed to measure the users’ perceived importance and dissatisfaction for each of the SAs. Based on these two measurements, a revised importance-performance analysis model was proposed to identify the SAs that should be improved. To validate the model, the dedicated container terminal of Evergreen Marine Corp. (EMC DCT) at Kaohsiung Port and its users were empirically investigated. With respect to the empirical results, managerial implications of the findings in improving service quality for the EMC DCT are discussed.     

An aggregate approach to model evacuee behavior for no-notice evacuation operations

This study proposes an aggregate approach to model evacuee behavior in the context of no-notice evacuation operations. It develops aggregate behavior models for evacuation decision and evacuation route choice to support information-based control for the real-time stage-based routing of individuals in the affected areas. The models employ the mixed logit structure to account for the heterogeneity across the evacuees. In addition, due to the subjectivity involved in the perception and interpretation of the ambient situation and the information received, relevant fuzzy logic variables are incorporated within the mixed logit structure to capture these characteristics. Evacuation can entail emergent behavioral processes as the problem is characterized by a potential threat from the extreme event, time pressure, and herding mentality. Simulation experiments are conducted for a hypothetical terror attack to analyze the models’ ability to capture the evacuation-related behavior at an aggregate level. The results illustrate the value of using a mixed logit structure when heterogeneity is pronounced. They further highlight the benefits of incorporating fuzzy logic to enhance the prediction accuracy in the presence of subjective and linguistic elements in the problem.     

A Theoretical Model on Solvus Line Prediction of Film and Its Application in Nanogranular Al-Cu System

A theoretical model on the solvus line prediction of a film was proposed and applied to a nanogranular Al-Cu system. The calculation results show that the solvus line of solute Cu will markedly lower with the decrease of grain size, namely, the starting temperature of θ(Al_2Cu) precipitation in a nanogranular Al-Cu film will markedly lower than that of conventional coarse grain alloy with the same Cu concentration, and the precipitation temperatures calculated are comparable with the experimental ones. The theoretical model can be simply used to calculate the starting temperature of precipitation in Al-Cu films under three states: ① films with substrate; ② films without substrate; ③ ultrafine grain bulk alloy. As a result, the model is universal, moreover, can be, in principle, used to predict precipitation temperature in other systems.     

Forecasting automobile sales: the Peña-Box approach

As a response to growing concerns regarding the call for clean energy and its impact on future automobile sales, this study uses a classical factor model and the Peña-Box model to examine the contemporary and time-varying relationships of different brands/models of cars in Taiwan between 2003 and 2007. In this paper, we demonstrate the complementary characteristics of these two analytical and forecasting methods. The results confirm that these two models can derive equally important but different information from the same time series data. Furthermore, the models are a useful marketing tool for discovering the current preferences of car purchasers, as well as their preference changes over time.     

Review of Countermeasures against Beach Erosion on the Taiwanese Coast

Beach erosion is one of the most significant coastal preservation problems in the world. This study first briefly addresses the influences of human activity on beach erosion. The seriousness of beach erosion in Taiwan has received considerable attention since the 1960s, following rapid population growth and economic development in the coastal areas. Hard solutions of stabilized structures against beach erosion in Taiwan at that time are reviewed based on their effectiveness in protecting property and their ability to produce a landscape that harmonizes with the adjacent coastal environment. Soft coastal defense solutions implemented recently in coastal regions in Taiwan are introduced and their benefits are discussed. This study concludes that various methods designed to prevent wave- and current-induced beach erosion should be based on analyses of nearshore hydrodynamics, sediment transport, coastal processes, and physiographic features of beaches.     

台北捷运新庄线隧道受毗邻建物深开挖影响案例探讨

台北捷运新庄线丹凤站至辅大站间隧道在完成钻掘工作后,因某建设公司错估隧道与基地建筑线之实际距离,又于施作中正路侧连续壁时发生坍孔,以致在其抢救过程中,造成位于中正路下方之捷运隧道,因灌浆压力挤压使得隧道上方部分环片向内变形.经现场详细检视受损隧道情形,发现于该建物新建工程之基地投影范围内之环数第439至第471环中,除第462环至第470环因变形量超出钢筋之安全负荷需进行环片补强外,另第459环因环片产生之裂缝在行车方向亦需补强.经结构计算后,本案受损环片自第459环至第470环皆采内衬钢环片进行补强,详载整个事件自开始至处理完成之过程,以作为日后类似工程处理之参考.