Performance Design of an Exhaust Superheater for Waste Heat Recovery of Construction Equipment

Although fuel cost has been the largest portion of annual operating costs of construction equipment, it is possible to save the energy and reduce cost using fuel economy enhancement technology. In this study, an organic Rankine cycle is applied to an excavator in order to recover waste heat, reproduce it into electrical energy, and consequently reduce the fuel consumption by 10 %. A design process was carried out to develop an exhaust gas superheater that recovers the waste heat from exhaust gas through a composite-dimensional thermal flow analysis. A one-dimensional code was developed to perform a size design for the exhaust gas superheater. The ranges for the major design parameters were determined to satisfy the target of the heat recovery, as well as the pressure drop at both fluid sides. Performance analysis was done through onedimensional design code results, which were compared with three-dimensional CFD analysis. By utilizing a 3D commercial code, the arrangement of the tubes was selected and the working fluid pressure drop was reduced through a detailed layout design. The design procedure was verified by a performance evaluation of the prototype, which yielded only a 7 % tolerance in heat recovery.     

基于地铁综合监控系统的环境设备监控系统应用技术

地铁综合监控系统集成或互联了环境设备监控系统等诸多子系统。对环境设备监控系统的神经网络感知、基于客流量模型灰色系统预测、设备优化控制技术,以及设备状态检修和RAMS(可靠性、可用性、可维护性和安全性)管理等应用技术进行了研究,这些应用技术能够更好地实现对地铁机电设备全面、高效的自动化监控及管理,保证设备安全、可靠、高效、节能地运行,并为乘客提供安全、舒适的乘车环境。     

Research on the coefficient of sound absorption in turbid water

China’s coastal waters are turbid and the properties of the seabed are complex. This negatively impacts the performance of underwater detection equipment. The properties of sound absorption in turbid water are not well understood. In this paper, the coefficient of sound absorption in turbid water was measured by the reverberation technique. All work was done in a reverberation barrel made of seamless aluminum. First, pure water was poured into the reverberation barrel and its reverberation time measured. Next, various concentrations of turbid water were poured into the barrel and their reverberation time measured. After all data had been gathered, the coefficient of sound absorption in turbid water of different concentrations was calculated. From this we determined a law of sound absorption in turbid water as summarized in the paper.     

How remote is remote pilotage?

“Today, the idea of allowing aircraft pilots to operate as they see fit, without any control from the land, is unthinkable. Will the same things apply to ships in twenty to thirty years’ time?”Current maritime pilotage regimes are clearly seen in some quarters as too restrictive and old fashioned. Change is “in the air” and VTS, pilotage, and the relationship between them cannot be immune to it. Subject to the attainment of the appropriate standards by both ships and their crews there is no practical reason why more flexible Vessel Traffic Management cannot be introduced. The required technology is largely available and, with the introduction of AIS, the required dynamic data can be available. Technical problems foreseen are believed capable of solution. The more significant obstacles to implementation are, therefore, largely political, commercial, organisational, and cultural. These issues are discussed in this paper taking into account the viewpoints of major stakeholders.     

结构动力学基于摄动法的高阶非线性随机有限元方法研究(英文)

Several algorithms were proposed relating to the development of a framework of the perturbation-based stochastic finite element method (PSFEM) for large variation nonlinear dynamic problems. For this purpose, algorithms and a framework related to SFEM based on the stochastic virtual work principle were studied. To prove the validity and practicality of the algorithms and framework, numerical examples for nonlinear dynamic problems with large variations were calculated and compared with the Monte-Carlo Simulation method. This comparison shows that the proposed approaches are accurate and effective for the nonlinear dynamic analysis of structures with random parameters.     

原发性肾病综合征患儿T细胞亚群及其抑制性细胞活性

本文检测了37例原发性肾病综合征患儿的外周血T淋巴细胞亚群和刀豆素A诱导的抑制细胞活性水平。结果显示,肾病患儿初发时就存在抑制性T细胞数量及功能的减低,并随着激素治疗及病情的好转而恢复正常,提示本病的免疫调节失衡可能是一原发性改变,在肾病发病机理中起一定的作用。     

国外海军多功能一体化隐形桅杆研究应用现状

随着现代作战舰艇探测设备、通信设备及电子战设备的增加,其电磁兼容和电磁隐蔽问题日益成为影响舰艇作战效能和生存能力的主要问题.为此,针对各种不同探测、通信及电子战设备研究设计一种多功能复合隐形桅杆势在必行.该文论述了美国、英国、意大利、荷兰海军在此方面的研究和应用现状.     

预应力等效荷载计算方法研究

预应力混凝土桥梁设计中将预应力作用转换为等效荷载的方式在桥梁结构分析中应用越来越广。根据作用力与反作用力的原理,推导了预应力等效荷载的计算公式及方法,该方法具有计算效率高的优点,适用于有限元编程电算,可用于空间预应力效应的计算,并附有算例。     

An application of a rank ordered probit modeling approach to understanding level of interest in autonomous vehicles

Surveys of behavior could benefit from information about people’s relative ranking of choice alternatives. Rank ordered data are often collected in stated preference surveys where respondents are asked to rank hypothetical alternatives (rather than choose a single alternative) to better understand their relative preferences. Despite the widespread interest in collecting data on and modeling people’s preferences for choice alternatives, rank-ordered data are rarely collected in travel surveys and very little progress has been made in the ability to rigorously model such data and obtain reliable parameter estimates. This paper presents a rank ordered probit modeling approach that overcomes limitations associated with prior approaches in analyzing rank ordered data. The efficacy of the rank ordered probit modeling methodology is demonstrated through an application of the model to understand preferences for alternative configurations of autonomous vehicles (AV) using the 2015 Puget Sound Regional Travel Study survey data set. The methodology offers behaviorally intuitive model results with a variety of socio-economic and demographic characteristics, including age, gender, household income, education, employment and household structure, significantly influencing preference for alternative configurations of AV adoption, ownership, and shared usage. The ability to estimate rank ordered probit models offers a pathway for better utilizing rank ordered data to understand preferences and recognize that choices may not be absolute in many instances.