Empirical approach for predicting the cetane number of biodiesel

The cetane number is an indicator of ignition quality and thus of fuel quality in the realm of diesel engines. It is conceptually similar to the octane number used for gasoline. Generally, a compound that has a high octane number tends to have a low cetane number and vice versa. The cetane number of a diesel fuel is related to the ignition delay time. In our work the first approach is a statistical one the accuracy of which depends upon the data obtained from various papers and literature sources, as all equations used were based on this data. During prediction using more than one equation is a good approach, as it provides the accuracy as well as the relative error. The second approach is also a statistical one, but its value depends upon the saponification number and iodine value. Therefore the accuracy of this equation may be higher, since we can collect the data for saponification numbers and iodine values from literature, without needing to calculate them. Using the saponification number and iodine value we can select an optimal biodiesel as generally a good biodiesel is selected using these three values. Thus the second approach allows us the freedom to select a biodiesel.     

OH-radical behavior of unsteady lifted flame based on instantaneous change of the equivalence ratio

In an earlier study, the current authors showed that an unsteady-state lifted flame generated by an equivalence ratio conversion system for a given fuel, was similar to a steady-state lifted flame in terms of the change characteristics from a premixed flame to a critical flame and then to a triple flame with a diffusion flame positioned in the middle according to the concentration difference. Therefore, this study used an OH-PLIF method to investigate the characteristics of a steady-state lifted flame and an unsteady-state lifted flame created under conditions identical to the flames in the preceding study. PLIF (Planar laser induced fluorescence) is practically effective for visualizing the concentration fields within a flame. The resulting OH-radical measurements showed that an unsteady-state lifted flame created under the specific conditions used in this study showed similar tendencies in terms of OH-radical distribution, fluorescence intensity, and liftoff height, to a steady-state lifted flame, thereby confirming that the behavior of an unsteady-state lifted flame can be effectively predicted based on the behavior of a steady-state lifted flame.     

Study of RCM-based maintenance planning for complex structures using soft computing technique

To guarantee the efficiency of maintenance strategies for a complex structure, safety and cost limitations must be considered. This research introduces RCM-based (Reliability Centered Maintenance) life cycle optimization for reasonable maintenance. The design variable is the reliability of each part, which consists of a complex structure, while the objective is to minimize the total cost function in order to maintain the system within the desired system reliability. This research constructs the cost function that can reflect the current operating condition and maintenance characteristics of individual parts by generating essential cost factors. To identify the optimal reliability of each component in a system, this paper uses a Neuro-Evolutionary technique. Additionally, this research analyzes the reliability growth of a system by using the AMSAA (Army Material Systems Analysis Activity) model to estimate the failure rate of each part. The MTBF (Mean Time Between Failure) and the failure rate of the whole system, which is responding to the individual parts, are estimated based on the history data by using neural networks. Finally, this paper presents the optimal life cycle of a complex structure by applying the optimal reliability and the estimated MTBF to the RAMS (Reliability, Availability, Maintainability, and Safety) algorithm.     

货真价实的四星：东风雪铁龙世嘉C—NCAP碰撞试验点评

东风雪铁龙世嘉是一款很有个性的两厢车,而它的原型车雪铁龙C4在欧洲有着很高的人气,所以世嘉自2008年10月上市以来市场表现还算是不错。由于原型车雪铁龙C4在欧洲的碰撞试验场上表现出色,获得了五星评价,所以地它国产之后在C-NCAP试验场上的表现也寄予了厚望。     

"卫星"号电动车组

介绍了俄罗斯“卫星”号电动车组的设计方案、技术特点以及所采用的设备     

The motion analysis of fire video images based on moment features and flicker frequency

In this paper, motion analysis methods based on the moment features and flicker frequency features for early fire flame from ordinary CCD video camera were proposed, and in order to describe the changing of flame and disturbance of non-flame phenomena further more, the average changing pixel number of the first-order moments of consecutive flames has been defined in the moment analysis as well. The first-order moments of all kinds of flames used in our experiments present irregularly flickering, and their average changing pixel numbers of first-order moments are greater than fire-like disturbances. For the analysis of flicker frequency of flame, which is extracted and calculated in spatial domain, and therefore it is computational simple and fast. The method of extracting flicker frequency from video images is not affected by the catalogues of combustion material and distance. In experiments, we adopted two kinds of flames, i.e. , fixed flame and movable flame. Many comparing and disturbing experiments were done and verified that the methods can be used as criteria for early fire detection.     

Multiple USV cooperative algorithm method for hunting intelligent escaped targets北大核心CSCD

[目的]针对无人艇协同围捕过程中逃跑目标具备智能性,现有无人艇策略难以围捕成功的问题,提出一种基于双层切换策略的多无人艇协同围捕算法。[方法]第1层围捕策略采用改进势点法,以无人艇与势点的总直线距离最小为优化目标,采用匈牙利算法为无人艇动态分配势点,并采用人工势场法实现无人艇的协同避碰;第2层围捕策略利用了阿波罗尼奥斯圆的性质,在两艘无人艇前往逃跑目标的目标点进行拦截,剩余无人艇运动方向保持与逃跑目标相同,以不断缩紧包围区域;为应对逃跑目标不同的逃跑方式,第1层围捕策略和第2层围捕策略可互相转化。[结果]仿真实验表明,该算法相较于顺序分配势点算法和极角分配势点算法,围捕时间更少或持平,证明了该算法的有效性和先进性。[结论]该多无人艇协同双层围捕算法,对具备典型智能性的逃跑目标具有围捕效果。     

欧洲客车设计案例剖析--伊利萨尔客车

旅游客车制造业是一个既专业又特殊的行业。乍一看,它理应归属于汽车制造业;但从产品的实际情形以及相对较小的年产量来看,它又应归属于手工艺品行业;在这里可以看到,机械制造结合了手工艺,汽车造型融入了建筑艺术。这篇文章概述了伊利萨尔旅游客车的设计过程:从与客户的第一次     

An analysis of bicycle route choice preferences in Texas,US

In the US, the rise in motorized vehicle travel has contributed to serious societal, environmental, economic, and public health problems. These problems have increased the interest in encouraging non-motorized modes of travel (walking and bicycling). The current study contributes toward this objective by identifying and evaluating the importance of attributes influencing bicyclists’ route choice preferences. Specifically, the paper examines a comprehensive set of attributes that influence bicycle route choice, including: (1) bicyclists’ characteristics, (2) on-street parking, (3) bicycle facility type and amenities, (4) roadway physical characteristics, (5) roadway functional characteristics, and (6) roadway operational characteristics. The data used in the analysis is drawn from a web-based stated preference survey of Texas bicyclists. The results of the study emphasize the importance of a comprehensive evaluation of both route-related attributes and bicyclists’ demographics in bicycle route choice decisions. The empirical results indicate that travel time (for commuters) and motorized traffic volume are the most important attributes in bicycle route choice. Other route attributes with a high impact include number of stop signs, red light, and cross-streets, speed limits, on-street parking characteristics, and whether there exists a continuous bicycle facility on the route.

A traffic analysis zone definition: a new methodology and algorithm

This paper develops a comprehensive approach to the definition of transportation analysis zones (TAZ), and therein, presents a new methodology and algorithm for the definition of TAZ embedded in geographic information systems software, improves the base algorithm with several local algorithms, and comprehensively analyses the obtained results. The results obtained are then compared to these presently used in the transportation analysis process of the Lisbon Metropolitan Area. The proposed algorithm presents a new methodology for TAZ design based on a smoothed density surface of geocoded travel demand data. The algorithm aims to minimise the loss of information when moving from a continuous representation of the origin and destination of each trip to their discrete representations through zones, and focuses on the trade-off between the statistical precision, geographical error, and the percentage of intra-zonal trips of the resulting OD matrix. The results for the Lisbon Metropolitan Area case study suggest a significant improvement in OD matrix estimates compared to current transportation analysis practises based on administrative units.