舰载直升机在舰艇编队对空预警中的使用研究

结合舰艇编队对空预警中存在的问题，指出了使用舰载直升机对空预警的必要性和可行性，论述了舰载直升机用于编队对空预警的优点以及配置方法，最后讨论了使用舰载直升机对空预警的几点注意事项。     

铁道行业标准《铁道车辆空气弹簧》修订介绍

介绍TB/T2841—2010《铁道车辆空气弹簧》修订的背景及国内外铁道车辆空气弹簧常用标准情况。对照JISE4206:1989《铁路车辆用弹簧装置》、EN13597:2003《铁道车辆用橡胶悬挂部件空气弹簧气囊》及TB/T2841—2005《铁道车辆空气弹簧》,详细说明TB/T2841—2010的适用范围、主要修订内容及主要参数的制定。     

车用空气压缩机性能试验台

车用空气压缩机性能试验台是用来测试车用空气同有关性能的试验检测设备，它由动力测量系统、气体测量、润滑、水冷却、风冷却、窜油量测试和专项测试等７个系统组成，详细介绍了各系统的结构组成、工作原理及测试项目。给出了各测试项目的测试范围、车用空气压缩机性能试验台系统图及回油量测试器图。     

必须重视汽车安全气囊的检验

安全气囊（ＳＲＳ）的发明始于１９５８年，其后普遍应用于飞机上的安全防护。８０年代后期，人们发现这种安全气囊与安全带配合使用对汽车乘员确实起到安全防护作用，９０年代末安全气囊已被广泛应用在汽车上。在美国还规定，从１９９５年１０月以后生产的汽车都必须安装安全气囊。 安全气囊的防护原理是，当汽车发生严重碰撞时，安全气囊即应自动打开，迅速地隔离在人与相对的物体之间。一方面起到了隔离作用，使人体的头部和胸部不会直接撞击在相对的物体上；另一方面可以吸收人体的惯性力，即吸收其能量，起到缓冲的作用，从而大大减少…     

The cumulative effect of nuisances from road transportation in residential sectors on the Island of Montreal – Identification of the most exposed groups and areas

Air pollution and road traffic noise are considered to be the two most important nuisances that could negatively affect the quality of life. A prolonged exposure to high concentrations of these pollutants could conduct to various health problems. Studies in environmental equity have often considered these nuisances individually whenever it comes from the same source. The main objective of this paper is to determine if the 15 years of age, those aged 65 and over, visible minorities and low income individuals located in a portion of the Island of Montreal are overrepresented in city blocks characterized by having among the highest levels of transportation-related air pollutants (i.e., ambient concentrations of NO₂ and road traffic noise in decibels (dB(A)). The results show that low-income individuals and, to a lesser extent, visible minorities, are significantly overrepresented in city blocks characterized by the higher levels of NO₂ and road traffic noise in dB(A). Multinomial logistic regression analysis confirms these results, and also shows that young people under 15 years are under-represented in the most polluted areas. However, contrary to the previous bivariate results, people aged 65 and over are negatively and significantly associated with the likelihood of their living in a city block located in an advantaged area after controlling for the independent effects of the other explanatory variables. Moreover, visible minorities are significantly overrepresented in advantaged areas. Considering the observed results, some solutions are identified to reduce road traffic noise and air pollution in the city blocks localized near major traffic arteries.     

高速铁路840 m全封闭声屏障气压荷载数值模拟研究

采用我国干线铁路开行的复兴号动车组,基于计算流体力学软件Fluent,对高速列车以350 km·h^-1速度通过840 m全封闭声屏障及1/2跨和1/4跨会车工况下声屏障的气压荷载分布规律进行数值模拟。结果表明:会车工况下的压力极值均大于单车工况下,且变化规律更为复杂,声屏障中间位置即1/2跨会车时的压力极值达到最大值,最大正压和负压分别为2 672和4 619 Pa,分别为单车工况下的2.05倍和1.87倍;同一截面各测点的气压荷载波动规律相似,但压力极值存在明显差异;单车工况下,声屏障同一截面上不同测点处的极值压差达到0.6 kPa,体现了压力波传递的三维效应。通过数值模拟获得的全封闭声屏障压力极值和气压荷载分布规律,为声屏障结构设计提供理论依据。     

Demonstration of reduced airport congestion through pushback rate control

Airport surface congestion results in significant increases in taxi times, fuel burn and emissions at major airports. This paper describes the field tests of a congestion control strategy at Boston Logan International Airport. The approach determines a suggested rate to meter pushbacks from the gate, in order to prevent the airport surface from entering congested states and to reduce the time that flights spend with engines on while taxiing to the runway. The field trials demonstrated that significant benefits were achievable through such a strategy: during eight four-hour tests conducted during August and September 2010, fuel use was reduced by an estimated 12,250–14,500 kg (4000–4700 US gallons), while aircraft gate pushback times were increased by an average of only 4.4 min for the 247 flights that were held at the gate.     

Non-exhaust particle emissions under various driving conditions: Implications for sustainable mobility

Non-exhaust particle (NEP) emissions from road traffic contribute significantly to Particulate Matter (PM) pollution in urban areas. The primary objective herein is to develop the knowledge required to move toward more sustainable mobility. NEP emissions are studied by means of complementary experiments on chassis dynamometers, on test tracks and at the roadside. Laboratory tests demonstrate that brake wear particles (BWP) emissions can change with braking force and frequency. A brake pad temperature threshold exists, above which the rate of ultrafine particle emissions is quite high. Below this threshold, the BWP emissions are dominant in the accumulation and coarse modes. Test track measurements have demonstrated that tire-road contact particle (TRCP) emissions considerably modify the atmospheric PM background especially for the supermicron fraction. Their number size distribution highlighted an ultrafine and accumulation modes centered at about 40 nm and 200 nm, respectively. The TRCP level increases with vehicle speed and during the acceleration and deceleration phases. Roadside measurements in the urban environment confirm the presence of NEP in significant proportions, in both the accumulation and coarse modes. The chemical composition of NEP differs depending on the size mode: BWP mainly stem from the degradation of brake pad lining materials, while TRCP are a mixture of tire tread wear and re-suspended dust. The presence of Fe-rich particles nevertheless serves as a good indicator of the NEP contribution to PM at the roadside. Lastly, in considering the parameters influencing NEP emissions, a series of recommendations are offered in order to achieve a more sustainable mobility.     

Forecasting demand for high speed rail

It is sometimes argued that standard state-of-practice logit-based models cannot forecast the demand for substantially reduced travel times, for instance due to High Speed Rail (HSR). The present paper investigates this issue by reviewing the literature on travel time elasticities for long distance rail travel and comparing these with elasticities observed when new HSR lines have opened. This paper also validates the Swedish long distance model, Sampers, and its forecast demand for a proposed new HSR, using aggregate data revealing how the air–rail modal split varies with the difference in generalized travel time between rail and air. The Sampers long distance model is also compared to a newly developed model applying Box–Cox transformations. The paper contributes to the empirical literature on long distance travel, long distance elasticities and HSR passenger demand forecasts. Results indicate that the Sampers model is indeed able to predict the demand for HSR reasonably well. The new non-linear model has even better model fit and also slightly higher elasticities.     

Effect of a speed reduction of containerships in response to higher energy costs in Sulphur Emission Control Areas

The objective of this paper is to explore the possible consequences of the future low-sulphur fuel requirements in Sulphur Emission Control Areas (SECA) on vessel speed, from the standpoint of the container shipping industry. Rational energy use, speed reduction, and revenues are closely related in the container shipping sector because speed reductions may provide substantial energy and cost savings. The operators could consider reducing their speed in SECA in order to save on fuel that will become relatively expensive. However, to maintain a weekly frequency without adding new ships, such a behaviour implies that the required speed at sea outside the SECA area increases. This paper aims to investigate if such a difference in speed is cost-effective, and if the increase in speed outside SECA may result in an increase in CO₂ emissions of the total cycle. We propose a cost model that estimates the cost-minimising combination of speeds inside and outside SECA, and the resulting CO₂ emissions of the liner service. Applying this model to representative liner services serving North Europe, we find that differentiating speed accordingly slightly decreases total costs and increases CO₂ emissions in a similar way. The results are sensitive to the price of low-sulphur fuels, the part of the cycle in SECA and the number of ships deployed in the service.