The effect of the competition between cars and trucks on the evolution of the motorway transport system

Motorways, which were devised at the beginning of their history as dedicated roads intended to be traveled by cars only, are at present also traveled by considerable flows of trucks. This fact has deeply changed the motorway transport system with respect to its original conception, owing to the interactions between two categories of vehicles whose characteristics are very different. These interactions greatly increase the transport cost perceived by car drivers with respect to truck drivers. This paper studies the consequences of this cost asymmetry on the evolution of the transport system when the geometric characteristics of a motorway remain unchanged in time, while transport demand increases. By using a theoretical model of competition between cars and trucks, it is shown that, if both the geometric characteristics of a motorway and the increase rate of the activities that feed the transport demand remain unchanged over time, the competition between cars and trucks, as well as the fact that in general passengers have better transport alternatives than freight, make the increase rate of truck traffic greater than that of cars, causing a progressive increase in the proportion of trucks in the time periods in which a motorway is traveled by both the vehicle categories. Since truck traffic on motorways, at least in Europe, is very scarce on weekends and in holiday periods, in which motorways are traveled almost only by cars, these results seem to indicate a tendency to the specialization of motorways, which are likely to be used in the future mostly by only one category of vehicles in different periods of time.     

另类快递

从包裹到食物甚至人体器官,世界各地的快递员运送各种快递。他们跟时间赛跑,与交通状况搏斗,竭尽全力保证货物能按时送到。     

黄渤:孩童以上成人未满

坐在化装间的椅子上便垂头睡着的黄渤,一旦进入了正式的工作状态,令人惊奇地精神焕发。在影棚里看到了两台玩具车模型,更是爱不释手,变得童心未泯。在拍摄当中,他也会让模型如真车一般开动起来,玩得不亦乐乎。飞鸟和鱼童心是他不肯放弃的内在气质。小时候黄渤就好玩儿,在青岛长大的他天生水性极好,特别喜欢到海边潜水,从小学开始一直到快20岁,都是只戴一个潜     

The car pooling problem: Heuristic algorithms based on savings functions

The present research deals with car pooling as a means of making better use of existing infrastructure and as a means of reducing traffic congestion with all its associated induced effects. Car pooling schemes involve several drivers getting together to share a private vehicle simultaneously, in order to reach their destinations points according to a semi‐common route rather than each driver using their own vehicle. The Car Pooling Problem belongs to the non‐polynomial computational complexity family of operations problems. In the current literature there are only a few studies on this optimization problem: the research group has designed several different new automatic and heuristic data processing routines to support efficient matching in car pool schemes. These are based on savings functions and belong to two distinct macro classes of algorithms to give two different modelings of this problem. They offer average savings of more than 50% in traveled distances demonstrating the effectiveness of a trivial matching scheme for real applications.     

重庆康明斯开启中国大马力电控柴油机新篇章

2009年9月15日,首台在华本地化生产的康明斯QSK19升大马力电控发动机在重庆康明斯正式下线,并交付工程机械知名企业——山推公司用于520马力推土机的新品上市。QSK19在重庆康明斯的投产．代表中国大马力电控柴油机正在向国际最领先技术迈进．此举填补了15升以上特大功率超低排放电控工程机械柴油机的国产化空白。     

Environmental sustainability in seaports: a framework for successful innovation

Environmental sustainability in the port industry is of growing concern for port authorities, policy makers, port users and local communities. Innovation can provide a solution to the main environmental issues, but often meets resistance. While certain types of technological or organisational innovation can be satisfactorily analysed using closed system theories, in the case of seaports and in particular in the area of environmental sustainability, more advanced conceptual frameworks have to be considered. These frameworks need to be able to account for the multiple stakeholder nature of the port industry and of the network and vertical interactions that environmental sustainability calls for. This article investigates successful innovations improving environmental sustainability of seaports. The proposed framework builds in part on research concepts developed in the InnoSuTra EU FP7 project. From a methodological perspective, this article develops a method for quantifying the degree of success of innovation with respect to a set of specific objectives. Several case studies are used to test the framework against real innovation examples, such as onshore power supply, or alternative fuels. In this article, we argue that only those innovations that fit dynamically port actors’ demands and the port institutional environment stand a chance to succeed.     

超未来汽车

2020年,听上去有些遥远,不知道那个时候的汽车都会变成什么模样?还像现在这样只用汽油、柴油吗?或者电油混合、纯电动力?还是有了更加先进的替代能源?外形是否能有更大突破,也许有更加环保的制作材料?为了缓解各个城市的堵车问题,上天、入地、下海似乎也不是没可能。对于未来,孩子们最有发言权,未来HOLD在他们手里,我们也有责任替广大的汽车厂商张罗奇思妙想,看看最有潜在购买力的人们和他们的第一汽车老师——他们的父亲对于汽车都有一些怎样的实际或者不实际的想法。     

兰博基尼太贵?那自己动手吧!

每每在街头,听到呼啸而过的一声轰鸣,伴随着的总是一部豪华跑车(当然很偶尔会是一辆改装的平民车或者更Low的电动车),接着身边都是一群"啧啧","哎呀富二代啊","哎呀好嚣张","哇好赞啊",诸如此类的或羡慕或仇富的声音。相信你我有时也都是其中之一,人之常情嘛。不过看过这一期之后,你也不用仅限于羡慕行列了,如果你真的疯狂喜爱这样一辆豪车,而荷包又并非如此富足,那机会就来咯。     

康明斯过渡第4阶段电控发动机全线登陆德国BAUMA展——2万小时工况实地测试、燃油经济性和系统集成优势成亮点

康明斯在排放技术领域一直是业内公认的“领头羊”。在2010年4月德国BAUMA展上．康明斯过渡第4阶段（Tier 4 Interim）电控发动机首次全线亮相,涵盖轻．中,重型系列,其阵容与2009年法国INTERMAT相比壮大许多。除了两款2009年面市的过渡4阶段中马力六缸发动机QSB6．7（排量6.7升,