Critical review of handling diagram and understeer gradient for vehicles with locked differential

The steady-state cornering behaviour of rear-wheel drive vehicles fitted with locked differential is critically analysed by means of simple, albeit carefully formulated, vehicle models, which allow for a rigorous theoretical analysis. Results obtained for some classical manoeuvres, with either constant forward speed, steer angle or turning radius, clearly show that, in the case of locked differential, the vehicle cornering behaviour is strongly affected by the manoeuvre. As an important consequence, the handling diagram is not unique and the understeer gradient is no longer dependent only upon the lateral acceleration, as in vehicles equipped with an open differential. Accordingly, this study shows that some typical tools and concepts of vehicle dynamics are indeed inadequate in the case of locked differential.     

内蒙古达斡尔族群体9个X-STR位点的遗传多态性及法医学应用价值评估

目的研究内蒙古达斡尔族群体9个X-STR位点(DXS6789、DXS101、DXS8378、DXS7132、DXS7133、DXS7423、DXS6804、DXS6799、HPRTB)的多态性分布及法医学应用价值。方法抽取内蒙古达斡尔族87名健康无关个体静脉血,提取DNA,经PCR扩增、变性聚丙烯酰胺凝胶电泳及银染显色技术进行等位基因分型;采用SPSS13.0软件计算各位点基因型频率和等位基因频率,并检验等位基因分布差异有无统计学意义;Genepop软件进行Hardy-Weinberg平衡检验;Fstat软件计算基因多态性、固定指数并检验固定指数偏离平衡的程度;Powerstats软件计算各种法医学应用指标。结果获得内蒙古达斡尔族群体9个X-STR位点等位基因频率分布的数据;进一步检验获得9个X-STR位点中DXS7133位点的多态性和分化程度较低;DXS7423和DXS7132位点在不同民族中基因分布差异无统计学意义。结论9个X-STR位点中,DXS6789、DXS101、DXS8378、DXS7132、DXS7423、DXS6804、DXS6799、HPRTB 8个位点有较高的遗传多态性和个体识别率,在个体识别和女孩的亲权鉴定中有较高应用价值,对疾病相关研究有实际意义。     

A Novel Approach to Reduce the Environmental Footprint of Maritime Shipping

Maritime shipping is a strategic sector with a strong international vocation and management. The need to define regulations valid for many different countries w...     

Experimental and numerical investigation on the derailment of a railway wheelset with solid axle

This paper presents the results of an experimental and numerical investigation on the derailment of a railway wheelset with solid axle. Tests were carried out under quasi-steady-state conditions, on a full-scale roller rig, and allowed to point out the effect of different parameters like the wheelset's angle of attack and the ratio between the vertical loads acting on the flanging and non-flanging wheels. On the basis of the test results, some existing derailment criteria are analysed in this paper and two new criteria are proposed. A model of wheel-rail contact is proposed for the mathematical modelling of the flange climb process, and numerical vs. experimental comparisons are used to obtain model validation.     

PB位相相干态的振幅平方压缩特性

研究了ＰＢ位相相干态的振幅平方压缩特性。结果表明，对于ｓ〉４的ＰＢ位相相干态均可存在振幅平方压缩特性，并给出了振幅平方压缩条件。     

ALTERATION IN CONTRACTILE RESPONSE TO NORADRENALINE,5-HYDROXYTRYPTAMINE, SARAFOTOXIN 6c, AND ANGIOTENSINⅡ IN RAT MESENTERIC ARTERY DURING ORGAN CULTURE

Theresistanceinindividualvascularbedsdeter minesthelocaldistributionofbloodflowtoandwithindifferentorgans.Thecontractilestateofanarteryiscontrolledbymediatorsreleasedlocallyfromnerveterminalsandendothelialcells ,andbycirculatinghormones .Thesemediatorsgiverisetoeffectsthroughtheirreceptors .Mediatorscanaffectvascularsmoothmuscleei therdirectly ,byactingonthesmoothmusclecellsthemselves ,orindirectly ,byactingonendothelialcellsoronnerveterminals ,especiallythoseofthesympatheticnervoussystem .Som…     

State Wetland Protection: A Matter of Context?

Models of integrated management emphasize the role of the surrounding socioeconomic and political environment in influencing management choices for natural resources. In this study, we explore a model that examines the influence of socioeconomic and political variables on the wetland management programs of U.S. states. Logistic regression was used to identify environmental, socioeconomic, and political variables that explained variation in state wetland programs. The likelihood of strong planning, nonregulatory, regulatory, and overall programs increases as the importance of fisheries in the state increases (p < 0.05), but decreases as population density increases (p < 0.15). Furthermore, there is an increasing likelihood of stronger regulatory and overall programs as environmental group activity and industry importance increases (p < 0.05). These findings provide empirical evidence to support the contention that management approaches used in one state often must be adapted to fit the realities of another given state.     

Accounting for inertia in modal choices: some new evidence using a RP/SP dataset

Inertia is related with effect that experiences in previous periods may have on the current choice. In particular, it has to do with the tendency to stick with the past choice even when another alternative becomes more appealing. As new situations force individuals to rethink about their choices new preferences may be formed. Thus a learning process begins that relaxes the effect of inertia in the current choice. In this paper we use a mixed dataset of revealed preference (RP)-stated preference (SP) to study the effect of inertia between RP and SP observations and to study if the inertia effect is stable along the SP experiments. Inertia has been studied more extensively with panel datasets, but few investigations have used RP/SP datasets. In this paper we extend previous work in several ways. We test and compare several ways of measuring inertia, including measures that have been proposed for both short and long RP panel datasets. We also explore new measures of inertia to test for the effect of “learning” (in the sense of acquiring experience or getting more familiar with) along the SP experiment and we disentangle this effect from the pure inertia effect. A mixed logit model is used that allows us to account for both systematic and random taste variations in the inertia effect and for correlations among RP and SP observations. Finally we explore the relation between the utility specification (especially in the SP dataset) and the role of inertia in explaining current choices.