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371.
Successful co-deposition of fine particulate matter within an Electroless Nickel-Phosphorous (ENi-P) matrix is dependent on various factors like bath composition, particle compatibility with metallic matrix, bath reactivity (pH), particle size and their distribution. ENi-P deposits incorporating Al2O3/Alumina in a disperse phase have varied effects on properties and attributes like surface roughness (Ra), microhardness, wear resistance, corrosion resistance and surface morphology of the deposits obtained. This paper experimentally investigates the effect of alumina (1.55 g/L) on Ra, microhardness, surface morphology, deposition rate, wettability, wear resistance and corrosion resistance of ENi-P-Al2O3 composite deposits on mild steel substrates at bath pH 5, 7 and 9. Study reveals that optimum deposit parameters and deposition rates are achieved with bath pH. However, not much study has been undertaken concerning composite deposits obtained from higher bath pH or basic bath. This is attributable to the fact that at higher bath pH or alkaline baths, the bath gets unstable and eventually degrades or decomposes, thereby resulting in sub optimal or poor deposition. Hence, experimental investigations carried out by preparing suitable baths, operating under optimum conditions, and enabling successful composite deposition in acidic and alkaline baths have revealed that there is a significant improvement in the above mentioned properties of the as-deposited composite deposits, as the pH is increased from pH 5 to pH 9. This aspect can therefore be advantageously utilized for preparing various marine components like fasteners, nuts, bolts, washers, pipes, cables, components having relative motion etc. 相似文献
372.
Jonas De Vos Patricia L. Mokhtarian Tim Schwanen Veronique Van Acker Frank Witlox 《Transportation》2016,43(5):771-796
Over the past decades research on travel mode choice has evolved from work that is informed by utility theory, examining the effects of objective determinants, to studies incorporating more subjective variables such as habits and attitudes. Recently, the way people perceive their travel has been analyzed with transportation-oriented scales of subjective well-being, and particularly the satisfaction with travel scale. However, studies analyzing the link between travel mode choice (i.e., decision utility) and travel satisfaction (i.e., experienced utility) are limited. In this paper we will focus on the relation between mode choice and travel satisfaction for leisure trips (with travel-related attitudes and the built environment as explanatory variables) of study participants in urban and suburban neighborhoods in the city of Ghent, Belgium. It is shown that the built environment and travel-related attitudes—both important explanatory variables of travel mode choice—and mode choice itself affect travel satisfaction. Public transit users perceive their travel most negatively, while active travel results in the highest levels of travel satisfaction. Surprisingly, suburban dwellers perceive their travel more positively than urban dwellers, for all travel modes. 相似文献
373.
Akhil K. Vaish Shijie Chen Neeraja S. Sathe Ralph E. Folsom Promod Chandhok Kuo Guo 《Transportation》2010,37(6):825-848
The National Household Transportation Survey (NHTS) was designed at the national level, and for most states it does not have a large enough sample to produce reliable estimates, especially for subdomains (e.g., age groups) within a state. Using the 2001 NHTS, we produced small area estimates (SAEs) of the percentage of persons among four age groups (17 or younger, 18–39, 40–54, and 55 or older) having high daily person-miles of travel (more than 87.5 miles a day, which is the 90th percentile for daily person-miles traveled) and associated prediction intervals for all 50 states and the District of Columbia. The survey weighted hierarchical Bayes (Folsom et al., Proc of the Sect on Surv Res Methods of the Am Stat Assoc 371–375, 1999) small area estimation (SAE) methodology was used to produce state-level SAEs. This paper describes the methodology and shows that SAE can be an effective technique for producing reliable state-level estimates from large, national surveys like the NHTS. In particular, the prediction interval relative widths for SAEs were, on average, 31–48% narrower than the corresponding design-based confidence interval widths, whereas for small states the reduction was around 47–63%. 相似文献
374.
Second-order estimates to measure platform reliability are generated and used to provide an additional space to select safety
margins appropriate to the owner's perception or for risk-averse managers. The aleatory and epistemic uncertainties in the
parameters of an offshore platform are explicitly considered in the reliability analysis and the platform structural reliability
becomes a random variable, assessing then the beneficial effects of a reduction on these uncertainties. One of these benefits
is for risk-aversive managers who often demand additional room to make conservative decisions regarding reliability estimations.
Proposed here is a procedure to generate the frequency diagram of platform reliability with the use of confidence bounds to
support reliability and cost decisions based on percentiles instead of mean values. The concepts are illustrated through a
typical offshore platform in Mexico. The frequency diagram of the platform reliability index is built for several alternative
designs and three levels of epistemic uncertainty. The results may be applied for decision making on new designs and also
on the assessment and optimal inspection, retrofit, and decommissioning of existing platforms. 相似文献
375.
Automotive transmission efficiency measurements are usually performed on purpose-built rigs. A simple model was developed
for calculating the overall transmission efficiency of passenger cars by using a chassis dynamometer. Wheel power and engine
output were measured, and these values were used for calculations. The proposed method can only be employed for vehicles with
manual drive because it requires constant speed measurements. Two case studies were investigated, with front-wheel and rear-wheel
drive passenger cars. The results obtained from using the proposed model are in good agreement with data provided in the literature. 相似文献
376.
J. Kim 《International Journal of Automotive Technology》2011,12(6):857-864
As one of the major handling performance factors of vehicles and tires, on-center handling is very important at high speeds
where safety and refinement are major concerns for the driver. In this paper, the steering wheel torque and vehicle response
characteristics that play an important role in on-center handling performance were quantified using a spring-mass-damper (SMD)
system. Using this system, the characteristics of steering wheel torque and vehicle response could be objectified with SMD
parameters such as those for the spring and damping. Experimental objective tests were performed by considering the process
by which the on-center handling is evaluated subjectively, and the SMD parameters were extracted from the measurement data.
From a statistical analysis of the subjective and SMD parameters for several vehicles and professional drivers, it was found
that the subjective assessment of on-center handling could be successfully explained using the suggested parameters. 相似文献
377.
通过对不同催化作用涂层的对比,特别是针对小型摩托车活性、耐久性和贵金属成本的应用设计,提出以钯为主要或单一活性贵金属化合物涂料的研究数据,这些数据是通过使用合成气体反应器,对涂敷后的催化剂进行模拟发动机废气测试得到的。通过试验表明,较低成本的富钯催化涂料可用于小型摩托车的有效减排。此外,在110mL缸头补气与125mL中间补气摩托车上,按照摩托车欧Ⅲ和国Ⅲ排放法规运行ECER40冷起动循环,对不同配方催化剂的活性进行了测试,这些结果将与合成气体反应器测试结果相关联。 相似文献
378.
This paper explores critical success conditions of collaborative planning projects in the area of urban transport, evaluating
the impact of new collaborative methods, instruments and processes on project performance. Hypothesis building is based on
a comparative, empirical research design, rather than on deductive theory construction. Potential critical success conditions
are derived from literature. Based on five urban transport planning projects in Gothenburg (Sweden), London (United Kingdom),
Milwaukee (United States), Tokyo (Japan) and Mexico City (Mexico), a rough set analysis of the five cases reveals validated
success conditions, which can be used for formulating hypotheses for further research or for policy and process improvement.
The results suggest that a dedicated management of the multi-actor network, a high diversity of actors, as well as an extensive
use of knowledge integration methods in combination with a high network density are critical success conditions of these planning
processes. Surprisingly, the extensive use of unilateral methods also showed to be an important success condition. The traditional
role of the planner will have to be complemented with the expertise of network and methodology management. The authors conclude
that rough set analysis can be a valuable addition to narrative, single-case analysis of collaborative urban transport planning
processes. 相似文献
379.
The paper presents a study on the incorporated probability that a tanker fleet meets a given permissible value of hull girder
strength loss. The analysis was based on a database of hull girder section modulus (HGSM) for as-gauged girth belts of tankers.
It was found that its mean value is below 5% over the entire life span of the analyzed tanker fleet. The Weibull probabilistic
distribution was found to best represent the time-varying HGSM loss. A method was developed for calculating the incorporated
safety of a fleet. As an example, the IMO requirement for a maximum HGSM reduction of 10% relative to its required value was
analyzed, accounting for time-variant HGSM loss and including a probabilistic model for coating longevity.
The views expressed in the paper are those of the authors and not necessary those of ABS. 相似文献
380.
Malcolm A. Clarke 《WMU Journal of Maritime Affairs》2002,1(1):71-84
Consignors of goods in international trade want their containers to move door to door whether by land, sea or air — smoothly, seamlessly and at predictable cost. What they actually get from the law is at best a jerky roller coaster: a series of contracts, one for each mode or stage of the journey, contracts with various people and with liability that varies too. All agree that the law should change but attempts to agree on an entirely new multimodal regime have failed. Recently attempts have been not to start again but to expand an existing and established regime. The latest of these, the UNCITRAL draft, is essentially maritime: it applies to the sea phase but and goes further to apply door to door except when its path is blocked by compulsory unimodal law. Has Venus at last arisen from the waves? And what will happen when Beauty meets the Beast in the form of CMR? This article addresses the problems that will be encountered by an ambitious amphibious instrument of this kind. — problems of integration, of compatibility with local legal culture, and of methodology. 相似文献