两起膨胀机烧瓦事故原因分析及教训

神马集团尼龙化工有限公司空分设备的透平膨胀机 ,因电网两起晃电事故 (电压瞬时波动 )造成停车 ,又因为操作失误和联锁装置有缺陷 ,造成烧瓦事故 ,教训深刻。     

Exploring motorcyclist injury severity in approach-turn collisions at T-junctions: focusing on the effects of driver's failure to yield and junction control measures

Research has suggested that motorcyclists involved in approach-turn crashes were much more injurious than any other crash-type. This paper investigates the determinants of motorcyclist injury severity resulting from such crash types that occurred at T-junctions, with emphasis on the effects of driver's failure to give way and various junction control measures. The ordered probit models of motorcyclist injury severity were estimated using the data extracted from the STATS19 accident injury database (1991-2004). Approach-turn collisions are categorised into two sub-crashes based on the manoeuvres motorcycles and vehicles were making prior to the collisions. The modelling results uncover several important determinants of injury severity: for example, injuries appeared to be greatest when an approaching motorcycle collided with a turning-right vehicle, and such effect was found to exacerbate injury severity when stop, give-way signs and markings controlled the junction. A turning-right driver that was identified to fail to yield to an approaching motorcyclist was also found to severely injure the motorcyclist. The findings of this study may offer guidelines for further research and provide some important preliminary evidence for the development of countermeasures that may help prevent the specific hazards from occurring.     

The special severity of occupational accidents in the afternoon: "the lunch effect"

The severity of occupational accidents suffered by construction workers at different hours of the day is analyzed in this study. It may be seen that the interval of time between 13:00 and 17:00 has incomprehensibly high rates of severe and fatal accidents in comparison with any other. We associate this higher accident rate with what we have termed the “lunch effect”. We studied 10,239,303 labor accidents in Spain over the period 1990–2002. The relationships between potential risk factors for occupational accidents around lunch in Spain, especially alcohol consumption are studied, using two methods: analysis of national archival data of 2,155,954 occupational accidents suffered by workers in the construction sector over the period 1990–2002 and a survey study. This study also seeks to contribute the opinions of the workers themselves regarding the causes that might explain this situation.     

基于方差分析的轮毂造型特征显著性研究

目的 探讨差异化的轮毂造型、受试者年龄、感知意象的显著程度,确定符合目标人群的电动车轮毂造型方案。方法 完成各有5组轮辐的8种不同风格的轮毂造型方案。获取与电动车整体造型风格一致的8个感知意象词汇,采用5段语义差分法对102名目标人群进行感知意象实验。采用单因素方差分析法,对主成分分析确定的“个性的”等6个重要的感知意象词汇进行比较分析,分别求得8种轮毂造型,以及高中低3个年龄层次的目标人群对电动车轮毂造型特征的感知意象的显著结果。结果 获得不同感知意象对差异化的电动车轮毂造型显著性的影响程度,掌握具有倾向性的感知意象对特定年龄层次人群的敏感程度,总结市场细分条件下的电动车轮毂造型特征的倾向性,并呈现各轮毂造型显著性的影响程度。结论 通过方差分析找到指定感知意象词汇中最敏感的受试者年龄层次,以及造型特征显著性最强、感知意象最突出的轮毂造型,为确保轮毂与整车造型风格的统一性,提供科学依据。     

Brittle and ductile failure of rocks: Embedded discontinuity approach for representing mode I and mode II failure mechanisms

In this work, we present a discrete beam lattice model with embedded discontinuities capable of simulating rock failure as a result of propagating cracks through rock mass. The developed model is a two‐dimensional (plane strain) microscale representation of rocks as a two‐phase heterogeneous material. Phase I is chosen for intact rock part, while phase II stands for pre‐existing microcracks and other defects. The proposed model relies on Timoshenko beam elements enhanced with additional kinematics to describe localized failure mechanisms. The model can properly take into account the fracture process zone with pre‐existing microcracks coalescence, along with localized failure modes, mode I of tensile opening and mode II of shear sliding. Furthermore, we give the very detailed presentation for two different approaches to capturing the evolution of modes I and II, and their interaction and combination. The first approach is to deal with modes I and II separately, where mode II can be activated but compression force may still be transferred through rock mass which is not yet completely damaged. The second approach is to represent both modes I and II being activated simultaneously at a point where complete failure is reached. A novel numerical procedure for dealing with two modes failure within framework of method of incompatible modes is presented in detail and validated by a set of numerical examples. Copyright © 2015 John Wiley & Sons, Ltd.     

基于“故宫文创”的产品价值感知与消费需求影响研究

目的 以“故宫文创”为例,从文化消费视角下探讨博物馆文创产品价值感知与消费需求间的关系,以期为博物馆文创产品开发提供新方法与新思路。方法 将情感、社会、功能质量、功能价格感知因素作为自变量,产品类别与价格区间作为调节变量,构建博物馆文创产品价值感知与消费需求关系模型;以17 204条“故宫淘宝”店铺产品在线评论为样本,运用文本挖掘法与LDA模型加以检验假设。结果 研究发现,博物馆文创产品价值感知显著影响消费需求,产品类别与价格区间对价值感知因素关系及消费需求之间起到显著调节作用。结论 情感、社会与功能质量3个价值感知维度对消费需求影响较大且较为均衡,功能价格感知相较呈现非敏感特征;各价值感知维度内具的体关键影响因素差异较大。     

How accurately does the public perceive differences in transport risks?: An exploratory analysis of scales representing perceived risk

This paper probes the extent to which the public accurately perceives differences in transport risks. The paper is based on a survey of a random sample of the Norwegian population, conducted in September 2003. In the survey, respondents were asked: “How safe do you think it is to travel by means of (bus, train, etc.)?” Answers were given as: very safe, safe, a little unsafe, and very unsafe. A cursory examination of the answers suggested that the Norwegian public was quite well informed about differences in the risk of accident between different modes of transport, as well as between groups formed according to age and gender for each mode of transport. This paper probes the relationship between statistical estimates of risk and summary representations of perceived risk more systematically. It is found that the differences in fatality rate between different modes of transport are quite well perceived by the Norwegian public, irrespective of the way in which perceived risk is represented numerically. The relationship between statistical estimates of risk and numerical representations of perceived risk for each mode of transport is more sensitive to the choice of a numerical representation of perceived risk. A scale in which the answer “very safe” is assigned the value of 0.01 and the answer “very unsafe” is assigned the value of 10 is found to perform quite well. When the perception of risk is represented numerically according to this scale, a positive correlation between statistically estimated risk and perceived risk is found in seven of the eight comparisons that were made to determine how well variation in accident rates according to age and gender for car occupants, car drivers, cyclists and pedestrians are perceived.     

On the prevention of accidents and injuries : A comparative analysis of conceptual frameworks

The meaning of prevention has changed as new applications of the concept have appeared. Ideas presented in eleven different conceptual frameworks are compared. Identification of the frameworks took place through searches in databases and relevant literature. Five are general by nature, while six relate to injuries and accidents. All are supported by just a few parameters, the time dimension being the most prominent. Compatibility was established on three additional dimensions: level (individual, organizational or societal); direction (“bottom-up” or “top-down”); and in relation to the trichotomy “host-agent-environment”. An attempt to synthesize all these dimensions into one general model of accident and injury prevention is presented.     

An explicit analysis of the lead time syndrome: stability condition and performance evaluation

Updating planned lead times in response to changing workload levels leads to erratic ordering behaviour, resulting in even larger variability in the workload levels and flow times. This phenomenon is called lead time syndrome, and describes the cyclic interaction between adaptive planned lead times and order sizes. Although it has been conceptually defined and intuitively accepted, formal analysis with analytical evaluation of the phenomenon has not been conducted. The objective of this paper is to provide a stronger understanding of the lead time syndrome, and to give new insights into the effects of frequently updating planned lead times. We develop a two-dimensional Markov process to model a single-item production process with orders released sensitive to the planned lead time. Using matrix-geometric methods, analytical results on the utilization level and the variability in the system are presented in relation to the frequency of updating the planned lead time. Although the average utilization level is always retained, the lead time syndrome causes an increase in the average workload level and the actual flow times of the completed orders. The variability of the planned lead time increases with the update frequency except at the utilization boundaries, where the relative effect of the update frequency diminishes.     

Impact of roadside features on the frequency and severity of run-off-roadway accidents: an empirical analysis

In the US, single-vehicle run-off-roadway accidents result in a million highway crashes with roadside features every year and account for approximately one third of all highway fatalities. Despite the number and severity of run-off-roadway accidents, quantification of the effect of possible countermeasures has been surprisingly limited due to the absence of data (particularly data on roadside features) needed to rigorously analyze factors affecting the frequency and severity of run-off-roadway accidents. This study provides some initial insight into this important problem by combining a number of databases, including a detailed database on roadside features, to analyze run-off-roadway accidents on a 96.6-km section of highway in Washington State. Using zero-inflated count models and nested logit models, statistical models of accident frequency and severity are estimated and the findings isolate a wide range of factors that significantly influence the frequency and severity of run-off-roadway accidents. The marginal effects of these factors are computed to provide an indication on the effectiveness of potential countermeasures. The findings show significant promise in applying new methodological approaches to run-off-roadway accident analysis.     

Routes to failure: analysis of 41 civil aviation accidents from the Republic of China using the human factors analysis and classification system

The human factors analysis and classification system (HFACS) is based upon Reason's organizational model of human error. HFACS was developed as an analytical framework for the investigation of the role of human error in aviation accidents, however, there is little empirical work formally describing the relationship between the components in the model. This research analyses 41 civil aviation accidents occurring to aircraft registered in the Republic of China (ROC) between 1999 and 2006 using the HFACS framework. The results show statistically significant relationships between errors at the operational level and organizational inadequacies at both the immediately adjacent level (preconditions for unsafe acts) and higher levels in the organization (unsafe supervision and organizational influences). The pattern of the 'routes to failure' observed in the data from this analysis of civil aircraft accidents show great similarities to that observed in the analysis of military accidents. This research lends further support to Reason's model that suggests that active failures are promoted by latent conditions in the organization. Statistical relationships linking fallible decisions in upper management levels were found to directly affect supervisory practices, thereby creating the psychological preconditions for unsafe acts and hence indirectly impairing the performance of pilots, ultimately leading to accidents.     

The use of stochastic stresses in the static approach of probabilistic limit analysis

In the framework of the structural reliability theory, the probabilistic limit analysis (PLA) represents a powerful tool for the evaluation of the safety of structures with stochastic strengths with respect to the ultimate limit state of plastic collapse. Aim of the PLA is to evaluate the conditional probability of collapse (CPC), that is, the probability of plastic collapse of the structural system for assigned value of the acting loads. In this paper the focus is on the static approach of the limit analysis theory, which is particularly attractive for engineers, because it gives upper bounds of the CPC, that is, safe bounds. The classical static approach, introduced more than 30 years ago, however, cannot in any case evaluate the exact CPC of the structural system, and moreover generally the bounds obtained are not very close, especially in the range of very small probabilities. In this paper an alternative static approach is proposed, which can obtain the exact CPC of the structural system considering a finite number of suitable chosen stochastic stress vectors through the use of the partial admissible domains; moreover, it gives good safe bounds of the CPC considering only a few stochastic stress vectors. Some simple numerical examples show the accuracy and effectiveness of the method. Copyright © 2007 John Wiley & Sons, Ltd.     

Effects of the feeling of invulnerability and the feeling of control on motivation to participate in experience-based analysis,by type of risk

Experience-based analysis (EBA) refers to a set of safety-management practices consisting of detecting, analyzing, and correcting the individual, material, and organizational causal factors of accidents in order to prevent their reoccurrence. Unfortunately, these practices do not always garner the adherence of employees. This article presents a study that examines the impact of risk perceptions on agents’ motivation to participate in EBA in various production sectors. The study was conducted at two sites, a chemical factory and a nuclear power plant, by means of a questionnaire administered to 302 employees. The results indicated that the feeling of control was not only positively linked to the feeling of invulnerability, but that these two factors were negatively linked to risk perception. In addition, the actors in both production sectors were more motivated to participate in EBA of accidents linked to the core processes of their industry (which were more accurately perceived) than in EBA of ordinary accidents (accidents not specific to chemical or nuclear processes). Moreover, the agents’ feeling of invulnerability and feeling of control both reduced EBA motivation for ordinary accidents to a greater extent than for chemical and radiation-related accidents. Recommendations are made in view of encouraging agents to get more involved in EBA.     

蜂窝夹层修理结构的弯曲性能试验分析

采用四点弯加载方式研究分析了含损伤蜂窝夹层修理结构的弯曲性能,该夹层结构由碳纤维增强的聚合物面板和蜂窝芯子组成。进一步分析了挖补斜度、挖补方式、损伤程度、修理设备和修理材料对修理板弯曲性能的影响。研究表明,修理板的破坏模式可分为补片边缘折断、补片中面折断和胶层破坏三种,相同破坏模式修理板的名义弯曲强度相近,其中前两种破坏模式修理板的名义弯曲强度与完好板相近,而第三种破坏模式修理板的名义弯曲强度相对较低。所有修理板的名义弯曲强度恢复率基本处于95%以上,同时修理后抗弯刚度也满足修理准则。     

A Framework for the Development of an Environmental Management System: A Case Study in a Thermal Power Plant

A framework for the development of an environmental management system that satisfies the requirements of the ISO 14001 standards is presented. The framework is developed for NB Power, a company producing electricity for the province of New Brunswick in Canada. A case study is carried out in a thermal power plant called Coleson Cove. An initial review of the existing environmental management programs is presented. The environmental policy is evaluated, and the environmental aspects and impacts of the plant's activities are identified and prioritized according to prespecified criteria of severity, frequency, degree of control, and existence of regulation. Environmental objectives and targets are set and recommendations are presented.     

Failure data analysis: the application of Excel spreadsheet add‐ins as an aid to curve fitting

This paper describes the application of the Solver function contained within Microsoft Excel® to generate solutions to a range of common failure data analysis problems. The capability of the Solver function is demonstrated and employed to determine the appropriate Weibull distribution parameters for single, minimum life, censored and mixed distribution data. The examples selected have been taken from existing published data sets. The paper is also supplemented with a further example, drawn from an industrial situation, in which the approach is applied to the determination of the extent of an early life failure problem in low‐voltage electrical contactor coils. Copyright © 2000 John Wiley & Sons, Ltd.     

Exploring the relationship between types of family involvement and collaborative innovation in design-intensive firms: insights from two leading players in the furniture industry

ABSTRACT

Innovation in family firms has attracted considerable interest from scholars and practitioners in recent years. However, further theoretical and empirical research is needed to illuminate the intricate relationship between family involvement and innovation. This article studies the effect of different types of family involvement on the management of collaborative innovation. Based on empirical evidence from two leading Italian design-intensive firms in the furniture industry (B&B Italia and Cassina), this study illuminates how family involvement in control and management influences the way design-intensive firms collaborate with external designers to innovate their products. We use two indicators, design renewal and design identity, to capture differences in collaboration approaches through which design-intensive family firms involve external designers. Thus, our findings contribute to understanding how collaborative innovation is managed in family firms. This article also provides family firm owners and managers with insights on the forces that influence the collaborative innovation processes in design-intensive firms.     

A numerical analysis of the mechanisms behind plasticity induced crack closure: Application to variable amplitude loadings

The effect of loading parameters on fatigue crack growth has been explained using the concept of crack closure. Plasticity induced crack closure (PICC) is linked to the crack tip plastic deformation, which becomes residual with crack propagation. The objective here is to identify the main mechanisms behind PICC, and for that different loading cases were considered namely overloads and load blocks. An analytical model was used to isolate the effect of residual plastic deformation on PICC, however significant differences were obtained relatively to finite element results. A second mechanism, which is crack tip blunting, was used to explain the transient behaviour observed after overloads and load blocks. For overloads and low–high load sequences there is a sudden increase of crack tip blunting with load increase which explains the sudden decrease of crack opening level. For high–low load sequences there is a sudden decrease of crack tip blunting which enhances the effect of residual plastic wake. Finally, the partial closure concept was tested looking to non-linear crack tip parameters but no evidences of Donald’s effect were found for the material studied.     

Evolution of Daily Hemodialysis in Acute Renal Failure: From the Korean War to the Present

Over half a century of hemodialysis therapy has brought significant progress in technology and in our approach to its use. This brief review has three objectives: (1) to describe what dialysis was like in the beginning, 50 years ago; (2) to review the origins and interval evolution of the paradigm of daily hemodialysis; and (3) to introduce some vistas for the future.