Determination of tetrachloroethylene—Results of a collaborative study and the standardized method

The development, by collaborative study, of a standardized method for the determination of tetrachloroethylene in olive oils is described. The results of the study, which was carried out in 1989 under the direction of the International Olive Oil Council (IOOC), are presented and show that tetrachloroethylene can be readily determined, to an acceptable degree of precision, by gas-liquid chromatography with electron capture detection. A limited number of results obtained for the determination of trichloroethylene and chloroform by the same method indicate that a similar precision could be obtained with the method when determining these solvents also.     

石油勘探开发行业可持续发展战略研究

从可持续发展的基本内涵出发，初步研究了石油勘探开发行业可持续发展的主要特征和指导原则，并提出了石油勘探开发行业可持续发展的若干主要对策。将可持续发展思想和战略逐渐融进石油工业业务活动中去，对我国石油工业的持续稳定发展具有十分重要的意义。     

压力容器爆破试验实验装置的设计与探讨

“压力容器爆破试验”实验的教学要求是：(1)能测定“压力——膨胀量”关系曲线;(2)能测定试验容器爆破压力;(3)爆破后能观察爆破口的形貌;(4)实验后便于恢复原始状态,适合教学反复使用等。根据上述要求,本文对“压力容器爆破试验”的试验容器、实验装置进行了设计与探讨。     

应用化学专业实践教学模式初探

介绍了以江西农业大学理学院基础化学实验室为基础,以2002级应化专业学生为对象,以培养具有“基础扎实、知识面广、能力强、素质高”的优秀化学人才为目标,改革应用化学专业实践教学内容和方法,改善实验条件.     

Mechanistic Insight in the Ethane Dehydrogenation Reaction over Cr/Al2O3 Catalysts

A Cr/Al₂O₃ alkane dehydrogenation catalyst exhibits a maximum in ethylene yield during an ethane dehydrogenation cycle. Isotopic labelling experiments with monolabelled ¹³C-ethane and deuterium were used to elucidate whether the initial activity increase could be due to formation of an active, larger hydrocarbon intermediate on the surface. The results strongly indicate that this is not the case, and instead point to a traditional reaction cycle involving adsorption of ethane to form an ethyl species, followed by desorption of ethene and hydrogen. Transient kinetic data suggest that ethane adsorption is the rate-determining step of reaction.     

180°矩形弯管流场的实验测量和数值模拟

对180°矩形弯管内的湍流流场用智能型五孔球探针进行了测量，同时采用FLUENT 6.2对其进行数值模拟。流场测量和数值模拟结果表明：180°矩形弯管由于流体旋转产生的离心力导致了弯管内压力分布的变化，使弯管内切向速度发生变化。切向速度在流体开始旋转0°~60°区间内侧的速度增大、压力减小，外侧的速度降低、压力增大；当转过60°截面后，外侧的速度增大、压力减小，内侧的速度降低、压力增大。     

Investigating dependencies in software requirements for change propagation analysis

ContextThe dependencies between individual requirements have an important influence on software engineering activities e.g., project planning, architecture design, and change impact analysis. Although dozens of requirement dependency types were suggested in the literature from different points of interest, there still lacks an evaluation of the applicability of these dependency types in requirements engineering.ObjectiveUnderstanding the effect of these requirement dependencies to software engineering activities is useful but not trivial. In this study, we aimed to first investigate whether the existing dependency types are useful in practise, in particular for change propagation analysis, and then suggest improvements for dependency classification and definition.MethodWe conducted a case study that evaluated the usefulness and applicability of two well-known generic dependency models covering 25 dependency types. The case study was conducted in a real-world industry project with three participants who offered different perspectives.ResultsOur initial evaluation found that there exist a number of overlapping and/or ambiguous dependency types among the current models; five dependency types are particularly useful in change propagation analysis; and practitioners with different backgrounds possess various viewpoints on change propagation. To improve the state-of-the-art, a new dependency model is proposed to tackle the problems identified from the case study and the related literature. The new model classifies dependencies into intrinsic and additional dependencies on the top level, and suggests nine dependency types with precise definitions as its initial set.ConclusionsOur case study provides insights into requirement dependencies and their effects on change propagation analysis for both research and practise. The resulting new dependency model needs further evaluation and improvement.     

Reasons for bottlenecks in very large-scale system of systems development

ContextSystem of systems (SoS) is a set or arrangement of systems that results when independent and useful systems are to be incorporated into a larger system that delivers unique capabilities. Our investigation showed that the development life cycle (i.e. the activities transforming requirements into design, code, test cases, and releases) in SoS is more prone to bottlenecks in comparison to single systems.ObjectiveThe objective of the research is to identify reasons for bottlenecks in SoS, prioritize their significance according to their effect on bottlenecks, and compare them with respect to different roles and different perspectives, i.e. SoS view (concerned with integration of systems), and systems view (concerned with system development and delivery).MethodThe research method used is a case study at Ericsson AB.ResultsResults show that the most significant reasons for bottlenecks are related to requirements engineering. All the different roles agree on the significance of requirements related factors. However, there are also disagreements between the roles, in particular with respect to quality related reasons. Quality related hinders are primarily observed and highly prioritized by quality assurance responsibles. Furthermore, SoS view and system view perceive different hinders, and prioritize them differently.ConclusionWe conclude that solutions for requirements engineering in SoS context are needed, quality awareness in the organization has to be achieved end to end, and views between SoS and system view need to be aligned to avoid sub optimization in improvements.     

Past and future of software architectural decisions – A systematic mapping study

ContextThe software architecture of a system is the result of a set of architectural decisions. The topic of architectural decisions in software engineering has received significant attention in recent years. However, no systematic overview exists on the state of research on architectural decisions.ObjectiveThe goal of this study is to provide a systematic overview of the state of research on architectural decisions. Such an overview helps researchers reflect on previous research and plan future research. Furthermore, such an overview helps practitioners understand the state of research, and how research results can help practitioners in their architectural decision-making.MethodWe conducted a systematic mapping study, covering studies published between January 2002 and January 2012. We defined six research questions. We queried six reference databases and obtained an initial result set of 28,895 papers. We followed a search and filtering process that resulted in 144 relevant papers.ResultsAfter classifying the 144 relevant papers for each research question, we found that current research focuses on documenting architectural decisions. We found that only several studies describe architectural decisions from the industry. We identified potential future research topics: domain-specific architectural decisions (such as mobile), achieving specific quality attributes (such as reliability or scalability), uncertainty in decision-making, and group architectural decisions. Regarding empirical evaluations of the papers, around half of the papers use systematic empirical evaluation approaches (such as surveys, or case studies). Still, few papers on architectural decisions use experiments.ConclusionOur study confirms the increasing interest in the topic of architectural decisions. This study helps the community reflect on the past ten years of research on architectural decisions. Researchers are offered a number of promising future research directions, while practitioners learn what existing papers offer.     

Kinetic study of the curing behavior of bismaleimide modified with diallylbisphenol A

The curing kinetics of bismaleimide modified with diallylbisphenol A were investigated for different ratios of 1,1′‐(methylene di‐4,1‐phenylene) bismaleimide and diallylbisphenol A with differential scanning calorimetry. Multiheating‐rate and isothermal methods were used to study the kinetics of the curing process. The results indicated that the activation energy changed with the extent of conversion. The activation energy obtained by the multiheating‐rate method was higher than that obtained by the isothermal method. Two kinetic models (autocatalytic and nth‐order) were successfully used to model the curing process. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2229–2240, 2003