计算机实验室局域网的管理与安全

随着网络技术的不断发展与应用，网络的管理与安全问题日益突出。本文归纳了局域网中关于管理和安全的一些典型问题，并给出了相应的解决方案。     

爆破挤淤水中冲击波特性分析及工程监测

以具体爆破挤淤工程为例,实测了水中冲击波力学测线和保护目标处的水中冲击波压力值,分析了爆破挤淤水击波的作用特性和传播衰减规律,给出了水中冲击波的经验计算公式,提出水击波压力安全控制标准。研究结果不仅保证了重点工程的安全施工和周围建筑的安全,而且有助于丰富爆破挤淤理论,指导类似工程实践。     

火电厂贮煤筒仓安全监测系统的研究与设计

文中介绍了某3×135MW煤矸石综合利用电厂贮煤筒仓安全监测系统。系统采用研华IPO610工控机为上位机,通过传感器对筒仓内贮煤温度、一氧化碳、可燃气体、烟雾及煤位等参数进行在线监测,软件系统采用力控ForceControl2.61组态软件制作人机界面。文中对系统的功能、硬件配置和软件编写进行了讨论,分析了各I/O模块的功能,并给出了流程框图。该系统具有较好的实用性和稳定性,并已成功的运用在实际生产中,对防止贮煤筒仓事故、实现输煤系统安全运行有一定参考意义。     

基于木马入侵的安全防护

随着计算机网络的广泛应用,网络安全问题日益重要。文章分析了木马的原理、木马入侵的基本步骤以及木马的特征,并从操作系统、安全工具、用户网络安全意识三个方面具体介绍了安全防护解决策略,在此基础上,还给出了对系统及网络进行实时监控协助进行安全防护的策略。     

Trade-off between Safety and Cost in Planning Construction Site Layouts

Planning construction site layouts involves identifying the positions of temporary facilities on site, and accordingly it has a significant impact on the safety and efficiency of construction operations. Although available models are capable of minimizing the travel cost of resources on site, they do not consider safety as an important and separate objective in the optimization of site layouts. This paper presents the development of an expanded site layout planning model that is capable of maximizing construction safety and minimizing the travel cost of resources on site, simultaneously. The model incorporates newly developed concepts and performance criteria that enable the quantification of construction safety and travel cost of resources on site. The present model is developed in three main phases: (1) formulating decision variables and optimization objectives in this site layout planning problem; (2) identifying and satisfying all practical constraints in this optimization problem; and (3) implementing the model as a multiobjective genetic algorithm. An application example is analyzed to illustrate the use of the model and demonstrate its capabilities in optimizing construction site layouts and generating optimal trade-offs between safety and travel cost of resources on site.     

Effect of Safety and Environmental Variables on Task Durations in Steel Erection

In spite of the efforts by government agencies, labor organizations, and researchers in the field of health and safety, injuries and fatalities continue to affect the construction industry. In 2002 the construction industry had the undesirable distinction of having two of the most dangerous occupations in the United States, with fatalities among structural steel workers at 58.2 per 100,000 workers (fourth highest rate) and among construction laborers at 27.7 per 100,000 workers (ninth highest rate). Costs associated with construction accidents, such as increased insurance premiums and medical expenses, and loss of productivity are also concerns in the industry. It has not been demonstrated how unsafe working conditions affect worker performance, and the impact of unsafe work practices on worker performance has not been quantified. This paper describes a methodology that included direct observation of steel erection activities and statistical analysis of task duration data. The data collected at steel erection sites included safety conditions such as the use of personal protective equipment (PPE), elevation of the work area, environmental conditions such as temperature and humidity, and worker performance in the form of task durations. Analysis of variance (ANOVA) analysis of 186 of steel erection task durations collected over a six-month period showed that the use of personal protective equipment (PPE), the time of day during which the operation was being performed, the elevation at which the work was being performed, and the presence of decking below the work area had statistically significant effects on the durations of steel erection tasks.     

Use of Trench Boxes for Worker Protection

Work in trenches can be very dangerous if workers are not provided with adequate protection against trench cave-ins. One method of providing for worker protection in trenches is with the use of trench boxes, widely used, engineered structures that permit workers to work safely in trenches. A study of the experiences of utility contractors with the use of trench boxes provided several notable findings that can help in implementing safe work practices in trenches. Most safety problems with the use of trench boxes are attributed to human error or judgment. For example, several respondents commented that workers were observed exiting from the trench boxes by walking up the backfill, a practice that exposes workers to the dangers of trench cave-ins. The importance of training was also evident in the results. Firms with better safety performance records conducted specialized training courses for their employees, and they provided more frequent training courses.     

中广核CPR1000核岛堆芯概念设计和安全裕度评估初探

CPR1000压水堆核电站是中广核集团20多年来经过渐进式改进和自主创新形成的中国改进压水堆核电站。CPR1000的参考设计是岭澳II期核电站加改进设计。在未来的10～15年内,CPR1000将是中广核集团主要建设的核电站类型之一。CPR1000的初始堆芯设计采用什么样的装料方式和燃料循环方式是必须首先解决和确定的重要设计前提,这是整个核岛设计、安全分析核执照申请的核心和基础。基于大亚湾核电站和岭澳核电站多年的燃料管理经验和运行经验以及国外类似核电站运行和设计经验,并且综合考虑了初始堆芯的特点和难点,以及不同堆芯设计和燃料管理策略的特点,对CPR1000的初始堆芯进行了设计。通过初步研究,本文提出了CPR1000初始堆芯采用的燃料组件类型,分析CPR1000采用从首循环开始进行18个月换料过渡的堆芯设计技术方案,并对CPR1000首循环实施18换料进行了堆芯设计安全裕度初步分析与评估。     

户用冷水机组压力安全设计概要

本文分析了户用冷水机组制冷系统的压力安全特点,指出应重视小型系统的本质压力安全特性,并充分加以利用.根据GB 9237的要求,讨论了压力安全设计原理与技术措施在户用冷水机组的应用.     

Modeling and testing of energy absorbing lightweight materials and structures for automotive applications

As a consequence of the increasing demands in automotive industry concerning crashworthiness and passive safety, the concern for energy management and safety demands also increases. The goal of energy management is to reduce the forces and stresses on an occupant or a pedestrian during a crash event; in some cases it may be possible to reduce the forces by a factor of two. This requires usage of new advanced materials in automotive components. Energy absorbing foams and other lightweight materials like plastics and polymer composites are increasingly used in automotive industry. Hence, extensive study of energy absorbing behavior of these materials as well as the automotive components is needed for further improvements in numerical modeling and crash simulations. The paper enlightens recent advances in investigation of mechanical properties and energy absorption ability of the mentioned lightweight materials as well as modeling with finite element codes for crash simulations.