双波纹管差压计质量的提高

低温贮槽、槽车测量内筒液位的仪器 ,国内、国外普遍采用的是机械式双波纹管差压计 ,此差压计适合在大的静态压力下、相对小的动态变压下使用。其特点是 :(1)全机械式 ,不需用电源。(2 )性能可靠 ,基本不用维护。(3)读值直观 ,能反应贮罐内液位全过程 :满罐、零位、液位现状 ,一目了然。(4)能短时承受单向受压冲击。但不希望出现此情况 ,因为单向受压将使仪表受损。仪表故障大都由单向受压造成。1998年以前 ,这种仪表全部依靠国外进口。但进价十分昂贵 ,而且在国内没有专门维修点 ,一旦损坏 ,给用户带来诸多不便及一定的经济损失。1998年 ,…     

Improving pilots' risk assessment skills in low-flying operations: the role of feedback and experience

Risk assessment is one of the most important skills that pilots are expected to acquire to ensure the safe and successful management of flight. The traditional approach to the development of these skills requires pilots to directly engage with potentially hazardous events. Using low-flying as a context, the present study sought to test whether engagement with hazards in a simulated environment, together with feedback concerning performance, would improve pilots' risk assessment during a subsequent simulated test flight. The results indicated that engagement with the hazards, rather than the provision of feedback per se, was associated with behavior that reduced the risk to the aircraft, while maintaining operational performance. It was concluded that exposure to hazards within a simulated environment could provide the basis for the development of risk assessment skills amongst less experienced pilots.     

Estimating the reliability of quality test results after operations for industrial items

Procedures are examined for monitoring items after operations by means of sensors of electrocontact type. Statistical models are considered for tests on various monitoring results for the limiting deviations of component sizes on the basis of analysis of the numerical characteristics of the experimental data. __________ Translated from Izmeritel’naya Tekhnika, No. 8, pp. 18–21, August, 2007.     

Improving the quality of data used in environmental economics research.

Valuing environmental goods through contingent valuation and through other survey techniques is difficult because of the lack of traditional markets for those goods. EPA provides leadership in overcoming these challenges, using focus groups, workshops, handbooks, and teams of distinguished economists to obtain more reliable economic data from the surveys. Agency economists have provided leadership in employing production economics tools to identify win-win approaches to solve pervasive and neglected environmental problems. In addition, we exploit the speed of sophisticated computers, building field runoff models into economic models and aggregating results from tens of thousands of field sites. These very flexible models provide much more credible, site-specific analyses than previous models, and they offer flexible and efficient remedies to support Total Maximum Daily Loads and other new programs.     

Improving the quality of water and air by standards

正The Ministry of Ecology and Environment recently released 15 new national standards on environmental protection in response to the needs of social and economic development and eco-environmental regulation.     

Improving the quality of aluminium diecastings by novel techniques

Conventional liquid metal diecasting entraps air and produces porous diecastings which cannot be heat treated without distortion. Processes will be described for the diecasting of semi-solid alloys which are produced in a thixotropic condition. Such alloys can be handled as if a rather soft solid but, when sheared in a diecasting machine, will flow like a somewhat viscous liquid. Because the alloy can be handled as a solid, metal billet handling equipment can be used and die design simplified. Because the alloy is forced into the die as a slurry, less turbulence occurs and sound diecastings can be produced. The lower temperatures used mean that half the latent heat has been removed and so lower die temperatures result in leses thermal shock and faster cycle times, thus improving the productivity of the diecasting process. The absence of porosity allows heat treatment operations to be carried out without distortion to provide castings with strengths approaching those of forgings. Methods of carrying this out will be described and examples shown.     

Improving the structural quality and adhesion of functional coatings

In this paper a method of improving the structural quality and adhesion of functional coatings due to the pulsed mode of operation of a vacuum arc plasma source is described. The experiments were carried out by producing a carbon-based coating on a molybdenum substrate by spraying a graphite cathode in the benzene vapors. Plasma flow control is provided by alternating connection of two power sources, which allows variable closure of electron and ion currents on the substrate. This mode of operation allows to alternate the mode of heating and active diffusion of particles into the substrate with the mode of their deposition, as well as to provide the process of formation and annealing of the coating layers.     

Using the theory of constraints to guide the implementation of quality improvement projects in manufacturing operations

Several studies have shown that more than 70% of all medium to large size companies (sales exceeding $19 million) have some form of quality improvement program in place. Based on independent studies by Arthur D. Little, Ernst & Young, and others, researchers have concluded that only about one-fifth of all QI programs achieve tangible results. One explanation for the disappointing results is that many quality improvement efforts are not results-oriented. The purpose of this paper is to demonstrate the value of using the theory of constraints for achieving a results-oriented quality improvement program.     

Improving the quality of student learning: a systems approach

The study of engineering student learning is only really beneficial when examined in real-life settings. Students have their own, sometimes reactionary ideas about what affects the quality of their learning. Learning does not take place in convenient isolation and has to be understood in terms of cognition, behaviour, affect and context. Engineering undergraduate education must be seen as fitting into the general system known as `Higher Education', where teaching and learning are inextricably linked. Students may be initiated into the type of learning required of them, but this can be negated by unsupportive teaching elsewhere in the curriculum. In an attempt to describe at least the factors internal to the individual, the authors suggest some of the contextual dimensions affecting how students operate in an engineering learning environment     

Determinants of organizational form: transaction costs and institutions in the European trucking industry

We explain why European trucking carriers are much smaller andrely more heavily on owner-operators (as opposed to employeedrivers) than their US counterparts. Our analysis begins byruling out differences in technology as the source of thosedisparities and confirms that standard hypotheses in organizationaleconomics, which have been shown to explain the choice of organizationalform in US industry, also apply in Europe. We then argue thatthe preference for subcontracting over vertical integrationin Europe is the result of European institutions—particularly,labor regulation and tax laws—that increase the costsof vertical integration.     

On differences in how operations and supply chain managers approach quality management

In this research, we administered surveys to operations and supply chain managers from different companies to better understand how they approached quality management. The underlying research question was whether the increased emphasis in supply chain management in the workplace had implications for how quality management is practiced and how quality-related values are emphasised. We found that those who identified themselves as supply chain managers utilised and emphasised quality tools and values to a greater extent than those who identified themselves as operations managers. The tools emphasised by supply chain managers included benchmarking, complaint resolution, design for the environment, ERP, supplier development, focus groups, and supply chain management. The primary theoretical implication of this study is that there exists an emerging field that we can term ‘supply chain quality’. This study provides a preliminary outline of the domain of this field.     

Improving quality in iron casting by optimizing sand recycling

Two previous studies of the application of the techniques of information technology and statistics to the relatively low-level records of a semi-automated iron foundry have been made. Each has contributed to better knowledge and understanding of variables of the casting process, in the course of solving a specific problem. Encouraged by the enthusiasm for and quality of record keeping evident during the studies, it was decided to use the same investigative approach to make a deliberate search for any opportunity that might exist for improving the quality and/or productivity of green sand moulding. Data collected over a period of ten weeks were analysed under four broad headings: products, input materials, process operations and control of process variables. A comparison of production figures from the start and finish of the datum period revealed a reduction in the mould rejection rate of 40 per cent with reductions in inputs of new sand and bentonite of 42 and 12 per cent, respectively. The seemingly onerous task of good process record keeping had proved to present an opportunity in disguise.     

An on-road study to investigate fatigue in local/short haul trucking

As a precursor to the present research, Hanowski et al. [FHWA Report no. FHWA-MC-98-029. Office of Motor Carriers, Federal Highway Administration, Washington, DC, 1998] conducted a series of focus groups in which local/short haul (L/SH) drivers provided their perspective on safety issues, including fatigue, in their industry. As a follow-up to the Hanowski et al. work, the effort presented here consisted of an on-road field study where in-service L/SH trucks were instrumented with data collection equipment. Two L/SH trucking companies and 42 L/SH drivers participated in this research. The analyses focused on determining if fatigue is an issue in L/SH operations. Of primary interest were critical incidents (near-crashes) where L/SH drivers were judged to be at fault. The results of the analyses indicated that fatigue was present immediately prior to driver involvement in at-fault critical incidents. Though it is difficult to determine with certainty why fatigue was present, the results suggest that drivers' off-hours behavior likely played a significant role in the fatigue experienced on the job. Another key finding of this research is that a small percentage of drivers were responsible for a majority of the critical incidents. This finding suggests that driver selection and monitoring could potentially improve safety in L/SH operations.     

Application of systems theory and operations research to river quality management

The mathematical tools applicable in the field of river quality management are reviewed in the order in which they are used in the actual process of building and applying river quality models. The types of models and their properties are discussed, and the important problem of parameter estimation is examined. The use of the models in steady-state and real-time optimal control studies is investigated. Finally, the embedding of river quality control problems into problems of wider scope is discussed. The methodologies are illustrated by applications to the Rhine river.

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Zusammenfassung Die mathematischen Methoden, die man in der Wassergüterwirtschaft anwenden kann, werden diskutiert, und zwar in der Reihenfolge, in der sie bei der aktuellen Problemlösung benutzt werden: Zunächst werden die Typen mathematischer Gewässergütemodelle und ihre Eigenschaften erörtert, danach wird auf das Problem der Parameterschätzung eingegangen. Dann wird die Benutzung der Gütemodelle zur Lösung von Problemen der optimalen Steuerung erläutert, wobei unterschieden wird zwischen stationären und instationären Problemen. Abschließend wird diskutiert, wie die klar definierten Probleme der optimalen Steuerung in den weiteren Kontext der Wassergütewirtschaft einzubetten sind. Die verschiedenen Methoden werden illustriert durch Anwendungsbeispiele, die sich alle auf den Rhein beziehen.

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Revised version of a paper read at the Annual Meeting of the Deutsche Gesellschaft für Operations Research, Regensburg, Germany, September 19–21, 1979     

Improving the quality of manually acquired data: Applying the theory of planned behaviour to data quality

The continued reliance of manual data capture in engineering asset intensive organisations highlights the critical role played by those responsible for recording raw data. The potential for data quality variance across individual operators also exposes the need to better manage this particular group. This paper evaluates the relative importance of the human factors associated with data quality. Using the theory of planned behaviour this paper considers the impact of attitudes, perceptions and behavioural intentions on the data collection process in an engineering asset context. Two additional variables are included, those of time pressure and operator feedback. Time pressure is argued to act as a moderator between intention and data collection behaviour, while perceived behavioural control will moderate the relationship between feedback and data collection behaviour. Overall the paper argues that the presence of best practice procedures or threats of disciplinary sanction are insufficient controls to determine data quality. Instead those concerned with improving the data collection performance of operators should consider the operator's perceptions of group attitude towards data quality, the level of feedback provided to data collectors and the impact of time pressures on procedure compliance. A range of practical recommendations are provided to those wishing to improve the quality of their manually acquired data.     

Impact of federal compliance reviews of trucking companies in reducing highway truck crashes

BACKGROUND: The compliance review (CR) is a federal program monitoring motor carrier safety performance and regulatory compliance. This study sought to assess the impact of CRs on reviewed trucking companies in reducing truck crashes. METHODS: Data was from the Motor Carrier Management Information System. Study subjects were trucking companies established during 1990-1995, had at least one truck, and remained active until April 2004. Truck crash data of these companies was examined from 1996 to 2003. The crash rates in 2003 and annual percentage changes in number of crashes were computed. Analyses were stratified by company size, organization, operation classification, and safety rating. RESULTS: Companies that received CRs had a higher crash rate than never-reviewed companies. Reviewed companies experienced a 39-15% reduction in number of crashes in the year the CR was performed. The reduction in crashes was observed in all reviewed companies regardless of company size, operation classification, type of organization, or safety rating. The reduction in crashes was sustained for at least 7 years after CRs. DISCUSSION: The study results were controlled for the year in which CRs were performed, crash trend, and CR selection bias. However, further studies, especially a randomized prospective longitudinal study, are needed to overcome the limitations that are associated with an observation study.