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1.
A correlational examination of 54 consecutive months of data from British Columbia on the relationships among the number of vehicles checked in police drinking-driving roadchccks, the number of driving while impaired (DWI) charges laid, the number and percent of alcohol-related casualty traffic accidents, and the extent of media coverage on drinking-driving (as measured by print media coverage), revealed that: the extent of media coverage, and not the extent of roadchecks or charging activity is probably the critical element in the reduction of drinking-driving accidents. The failure of the minimally publicized April–May 1984 British Columbia police roadcheck “blitz” to reduce either the number or proportion of alcohol-related casualty traffic accidents lent support to these correlational findings.  相似文献   

2.
A review of recent Scandinavian legislation and practice finds that tendencies to liberalization and rationalization are becoming evident in the approach to controlling drunk driving. Imprisonmeent is less often used as a standard penalty, especially in Finland, Denmark, and Sweden, and there is increasing use of fines and therapeutically-oriented sentences. The degree of punitiveness in sentencing is being more closely related to what may be perceived as the moral quality of the offense, such as the quantity of alcohol in the offender's blood and the extent to which the offender is a repeater. Scandinavian law has been rationalized partly through the adoption in Denmark and Finland of chemical test-based definitions of the drinking-driving offense, and the provision in all four Northern countries of authority for police to conduct “random” breath tests of drivers.

Analysis of drunk-driving indexes suggests that the liberalization has been accomplished without a significant price being paid in terms of numbers of impaired drivers on the highways. There is some suggestion that “random” testing has the potential for increases in deterrence, but the very restrained use of this technique prevents firm conclusions at this time.

The continued commitment of the Scandinavian countries to a criminal-law approach to the problem of drunk driving seems paradoxical in the light of evidence that in these countries it is a very small and clinically identifiable fraction of the population that drinks and drives.  相似文献   


3.
Concentrating on local behavior of a highly stressed zone ahead of the crack tip, a recent mechanistic approach to analyse LEFM fatigue crack growth behavior in three stages at stress ratio R = 0 is extended here to include the effect of a positive stress ratio. This paper is limited to analysing primarily the stages I and II of “crack-ductile” materials, characterised by a purely “reversed shear” (or ductile “striation”) growth mechanism in stage II. It is shown that in these materials stage I is R-sensitive and stage II is insensitive, and these can, without invoking crack closure arguments, be rationalised alternatively by considering the dominance of a Kmax-controlled “Submicroscopic Cleavage” and a ΔK-controlled “ reversed shear ” fracture mechanism, respectively. Assuming Paris type power relations to hold, a predictive model is developed that contains separate growth equations with R-effect for stages I and II and shows the existence of a characteristic “master shear-curve” and a “moving pivot-point” on this curve for a class of materials. Good agreement was found between quantitatively predicted growth curves at selected R-values and a relatively large volume of available experimental data for low strength steels, aluminum alloys and titanium alloys. Besides providing more physical explanations for the observed growth behavior, the model may also be useful as a convenient alternative to crack closure for obtaining fairly accurate and conservative estimates of fatigue life for design applications.  相似文献   

4.
This paper firstly examines the relationship between state coordination and wind energy growth by comparing the differences between UK and German institutional configurations and state involvements in the 1990s. While the EU was calling for a unified regulatory framework for its member states, the UK and Germany adopted very different renewable energy policies. The evidence of the early 1990s shows that the British government employed “deregulation” with so limited state involvement that wind energy project developers faced thorny development problems, while the German government tried to require the electricity supply industry to purchase expensive wind power by “regulation” but encountered formidable resistance. Nevertheless, both the British and German administrations later could resolve these problems through new forms of state power. This suggests that, firstly, neither “deregulation” nor “regulation” is an effective means to develop wind power with increasing electricity liberalization and regionalization. Secondly, “obliging” regulations and state powers are vital to the policy outcome by harnessing the state's institutional capacity to smooth out technology innovation and diffusion.  相似文献   

5.
Many practical problems of quality control involve the use of ordinal scales. Questionnaires planned to collect judgments on qualitative or linguistic scales, whose levels are terms such as “good,” “bad,” “medium,” etc., are extensively used both in evaluating service quality and in visual controls for manufacturing industry. In an ordinal environment, the concept of distance between two generic levels of the same scale is not defined. Therefore, a population (universe) of judgments cannot be described using “traditional” statistical distributions since they are based on the notion of distance. The concept of “distribution shape” cannot be defined as well. In this article, we introduce a new statistical entity, the so-called ordinal distribution, to describe a population of judgments expressed on an ordinal scale. We also discuss which of the traditional location and dispersion measures can be used in this context and we briefly analyze some of their properties. A new dispersion measure, the ordinal range, as an extension of the cardinal range to ordinal scales, is then proposed. A practical application in the field of quality is developed throughout the article.  相似文献   

6.
The deposition rate and the thickness uniformity of chemical vapor deposition (CVD) titanium nitride films depend on wafer temperatures. The heater surface conditions, such as flatness, roughness, and surface imperfections, can greatly affect heat transfer efficiency from the heater surface to the wafer, and the process performance. Because heater surface imperfections or “hot spots” that caused poor uniformity had to be eliminated, the origin of “hot spots” was identified by a detailed study of heater surface profiles. A better visualization of “hot spots” could be obtained by comparing wafer-chucking patterns with deposition patterns. Thus, the time needed to locate “hot spots” could be shortened. The manufacturing process was revised to prevent “hot spots” and improve heater performance.  相似文献   

7.
Comprehensive arrest histories were obtained for 353 DUI offenders who were referred to a probation and rehabilitation demonstration program. The average number of total offenses was 7.9, with 89% of all tracked offenders having more than one offense. Approximately 63% of all recorded offenses were other types of offenses besides DUI. The overall arrest history profile of the group suggested that many DUI offenders are habitual violators of other laws as well. To identify distinctive arrest profiles within the referral sample, a Q mode factor analysis followed by a discriminant function analysis was used to classify offenders into profile subgroups. Five distinctive subgroups emerged. A “low offense” group was characterized by the lowest average number of overall arrests and also contained all offenders with no arrest besides the index DUI arrest. A “mixed” group had a higher average number of total arrests than the “low offense” group and diverse types of offenses. A young “traffic” group was distinguished by many hazardous moving violations other than DUI. Two smaller and older groups—a “public drunkenness” group and a “license” group—had the highest average number of arrests including DUI, public drunkenness, license violations, equipment violations, disturbance arrests and assault arrests. These subgroups were found to differ on demographic variables and drinker status variables. The “public drunkenness” group was found to have the highest accident rate. Groups were compared to groups found in other cluster analyses. Also, treatment implications were discussed. It was suggested that treatment programs focusing exclusively on changing alcohol consumption behavior are not likely to reduce accident risk for some of the offender groups. For example, it was suggested that effective intervention for the “traffic” group should target driving behavior, whether drunk or sober, rather than focus exclusively on consumption behavior. Other alternatives are also discussed.  相似文献   

8.
A recently proposed mechanistic model for the effect of stress ratio, R, on the LEFM (long) fatigue crack growth behavior of “crack-ductile” materials is extended here to explain and predict similar behavior under similar conditions of “crack-brittle” materials characterised by the presence of “static” modes of fatigue fracture in stages II and III. It is shown that in these materials the stage I behavior is similar, but the stages II and III behave differently from crack-ductile materials. Mechanism-based existence of two types of stage II curves characterised respectively by “ pure shear mode ” (SM-II) and “mixed-mode” (MM-II), both plotting linear but having different slopes, is introduced. It is shown that while stage SM-II is insensitive, stage MM-II is significantly sensitive to R, in the same material. Similar to stage I, another “ moving pivot-point ” exists at the transition from SM-II to MM-II, which slides down the “ master shear-curve ” with increasing R. Assuming a critical Kmax for the initiation of static modes, a critical R for saturation of these modes, and Paris-type growth relations, a quantitative predictive model containing growth equations for stages SM-II and MM-II, has been developed. Stage III is discussed only qualitatively. Reasonably good agreement was found between predicted curves at selected R-values and a relatively large volume of experimental data for steels, Al-alloys and Ti-alloys. This simple, alternative model may be used for obtaining quick, fairly accurate and conservative estimates of R-influenced crack growth rates for design applications in preference to crack-closure which frequently requires elaborate and tedious experimental procedures.  相似文献   

9.
The possible effect of proposed cyclic fluctuations of human sensitivity (28 days), intelligence (33 days), and physical (23 days) characteristics on motor vehicle accidents and fatalities was examined. Three methods of calculating these theoretical cycles were also examined. One method, the “Biomate” computer, was found to be unreliable in that it indicated 10.6% more days designated by the theory as critical than were actually present in a 300 case sample. In a sample of 141 motor vehicle fatalities (64 drug-free and 77 drug-associated) no correlation with the theoretical critical days was found for either group beyond that expected from random distribution. No evidence was found to support the increased likelihood of accident involvement on the “critical day” as implied by the concept of the “biorhythm” theory. Several possible sources of error in previously published reports are discussed.  相似文献   

10.
A CopleyTM fraction collector and a DisotestTM flow-through system were coupled to provide an automatic discrete sampling flow-through dissolution system for use both in the “open-loop” and “closed-loop” mode. The system was used to investigate the release characteristics of adinazolam in sustained release formulations using a pH 1.2 simulated gastric fluid (without enzymes) dissolution medium (USP XXI). These experimental formulations are designed to provide relatively slow to rapid drug release. The dissolution effluent was analysed off-line by reverse phase HPLC to determine the adinazolam concentration at programmed timed intervals. The differential dissolution profiles produced when the system is used in the “open-loop” configuration are more discriminating in describing the release characteristics of the formulations according to the relative release rates than the “closed-loop” cumulative profiles. Using the characteristic dissolution time parameter from the Weibull function, a better correlation with in vivo bioavailability data was achieved for the data from the system in the “open-loop” mode than when it was used in the “closed-loop” mode. In the “open-loop” mode the Weibull function characteristic dissolution time parameter yielded the best quantitative correlation with a correlation coefficient of 0.92 compared to a value of 0.85 for the “closed-loop” configuration  相似文献   

11.
Despite the fact that Hawaii has one of the highest seat belt use rates for passenger vehicles in the United States, and has had a mandatory seat belt use law since the 1980s, studies have shown that commercial motor vehicles (CMV) seat belt use rates are low. To better understand this phenomenon, a comprehensive survey of commercial vehicle drivers was conducted in Hawaii to ascertain attitudes and self-reported behaviors regarding seat belt use. A total of 791 drivers responded to a written questionnaire implemented at weigh stations and distributed to various trucking firms and transport centers. Approximately 67% reported that they use seat belts “always” when driving a CMV (commercial motor vehicle), yet when asked how often do other CMV drivers use seat belts, only 31% responded “always.” Interestingly, 86% of these same drivers reported that they use seat belts “always” when driving a personal vehicle. The major reason cited for non-use of belts was “frequent stops/inconvenience” (29%), and “not safety conscious” (23%). Notably, the self-reported use of safety belts is highest among operators of vans (88% said “always”), followed by buses (87% said “always”) and lowest among truck drivers (only 60% said “always”). In this paper, some of the differences between self-reported users and non-users are explored and a multivariate logit model was developed to predict the odds of belt use as a function of various factors.  相似文献   

12.
This paper presents an approximation model for determining minimum cost preventive maintenance schedules where accurate failure data are not available except the “average” (mean) and the “typical” value (mode) of the component lifetime.  相似文献   

13.
Bum-in, a screening technique to improve product reliability, is especially useful for highly integrated circuit systems. But, in most applications, the resulting systems reliability after burn-in is worse than what has been forecasted, because of “incompatibility” not only among components but also among different subsystems and at the system level. To deal with this phenomenon, we present a simulation method to compensate for the lack of field data. Also, a stress-strength model is implemented using weighted factors and a model based on nonlinear programming theory is designed to find the optimal burn-in policy that satisfies the reliability requirement and cost restriction. The program presented here can serve as an “IC Information Query System” for system designers to consider at the design stage.  相似文献   

14.
P.S. Liu   《Materials & Design》2007,28(10):2678-2683
Foamed metals have been widely used as various engineering materials, and their mechanical properties have also been drawing extensive attention. In the present paper, a new mechanical and analytical model is established for these materials with isotropic three-dimensional reticulated structure under biaxial tension, and the mathematical equation about biaxial nominal stresses is deduced for the biaxial tension at the beginning of failure of the porous body. With the relevant experiment, the relation formula is proved to be very effective. Different from the relevant theoretical system of Gibson and Ashby, the present mathematical relationship can be conveniently achieved from directly using the “beam theory” on this mechanical and analytical model. In addition, this relationship can be further expressed as the mathematical relationship among the nominal failure “deviatoric stress”, the nominal failure “average stress” and porosity, but the concepts of both the “deviatoric stress” and the “average stress” can appear just from the mathematical treatment.  相似文献   

15.
A series (SPUN) of segmented polyurethanes reinforced with the in situ-generated sodium silica-polyphosphate nano-phase (SSP) was characterized by thermogravimetry, differential calorimetry, wide-angle and small-angle X-ray diffraction and stress–strain relationships.

Cross-over from the rubber-like to the solid-like mechanical behavior of the SPUN above the apparent percolation threshold w ≈ 40% was considered as evidence for the onset of the “infinite clusters” of SSP nano-domains spanning the entire volumes of initial (i.e., undeformed) samples. The infinite clusters of SSP nano-domains crossed over from the mass fractal-like to the surface fractal-like behavior at the composition-dependent, characteristic X-ray scattering vectors q*. A continuous nano-phase of the polyurethane coexisting with a continuous nano-phase (infinite cluster) of the SSP is likely to be expanded due to the “negative pressure” effect.  相似文献   


16.
17.
The paper criticizes the currently dominant view of organization forms as “discrete alternatives” and “coherent” set attributes, and proposes a more refined and micro-analytic view of organization forms as particular combinations of coordination mechanisms and rights allocations. This view is relevant for understanding and devising “new” forms and proposing solutions for governing the composite and fast changing systems of today. The view is “relational” as it offers a procedure for devising “superior” configurations as combinations—relations between organizational components—in a quasi-continuous space of possibilities. The approach is sustained by the quantitative methods of network analysis as applied to relations among firm's resources and activities. Theoretically, the approach revisits organization design, integrating classic organization theory tenets with the new inputs provided by organizational economics. Substantively, it is argued that a mix of much differentiated coordination mechanisms is usually superior to the codified, “packaged”, allegedly “coherent”, forms of organization. The procedure presented in the paper is applied to a field experiment in a medium size firm.1  相似文献   

18.
Various “living” polymers were grafted onto C60 The number of arms of the so obtained “star” molecules can be controlled by stoechiometry and/or by varying the reactivity of the carbanion on the “living” chain against a double bond on the C60. Even the oxanion of “living” polyethylenoxide is able to add onto the reactive double bonds on C60. In some conditions, the carbanions present on these alkaline salts of grafted fullerenes becomes able to initiate anionic polymerization of vinyl monomers. Using “living” poly(phenylvinylsulfoxide) as a precursor polymer for PA, polyacetylene chains could be attached to the fullerene.  相似文献   

19.
In impact ionization studies the target normally consists of a metal surface of compact solid density. In the present experiments, we investigate the use of a layer of a highly porous structure of nanometre-sized grains, sometimes also called “metal black”, as an alternative target. In our comparative experiments, spherical iron particles (0.1<dp<1.5 μm) were shot with velocities 2–30 km/s onto both a compact solid silver plate and a silver metal black layer of about 7 μm thickness (grain size 20–40 nm, mean density ≈1 g/cm3), deposited on a compact solid gold plate. Impact generated ions were analysed by means of time-of-flight mass spectrometry. The results reveal important advantages of the porous black layer, such as better mass resolution and a larger amount of ions from the impacting particle. Therefore metal blacks may be very suitable targets for the purposes of identification and characterisation of the impacting particle's composition. An attempt is made to give a physical explanation of the results in the frame of existing empirical ionization models. The study is part of a programme to improve devices for in-situ analysis of fast moving cosmic dust particles.  相似文献   

20.
In designing targets for laboratory long-rod penetration tests, the question of lateral confinement often arises, “How wide should the target be to exert enough confinement?” For ceramic targets, the problem is enhanced as ceramics are usually weak in tension and therefore have less self-confinement capability. At high velocities the problem is enhanced even more as the crater radius and the extent of the plastic zone around it are larger. Recently we used the quasistatic cavity expansion model to estimate the resistance of ceramic targets and its dependence on impact velocity [1]. We validated the model by comparing it to computer simulations in which we used the same strength model. Here we use the same approach to address the problem of lateral confinement.

We solved the quasistatic cavity expansion problem in a cylinder with a finite outside radius “b” at which σr (b) = 0 (σr = radial stress component). We did this for three cases: ceramic targets, metal targets, and ceramic targets confined in a metal casing. Generally, σr (a) is a decreasing function of “a” (“a” = expanding cavity radius, and σr (a) = the stress needed to continue opening the cavity). In the usual cavity expansion problem b → ∞, σr (a) = const., R =−σr (a) (R = resistance to penetration). For finite “b” we estimate R by averaging σr (a) over a range o ≤ a ≤ ar, (where ar, the upper bound of the range, is calibrated from computer simulations).

We ran 14 computer simulations with the CTH wavecode and used the results to calibrate ar for the different cases and to establish the overall validity of our approach.

We show that generally for Dt/Dp > 30, the degree of confinement is higher than 95% (Dt = target diameter; Dp = projectile diameter; and degree of CONFINEMENT = R/R; R∞ = resistance of a laterally infinite target). We also show the tensile strength of ceramic targets (represented by the spall strength Pmin) has a significant effect on the degree of confinement, while other material parameters have only a minor effect.  相似文献   


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