Fuel choices in rural Maharashtra

We report on and analyze the results of an energy use survey in two tribal villages in rural Maharashtra, India. Though there is significant heterogeneity between the effects of the variables in the two villages there are some robust results. We find modest evidence for the ‘energy ladder’ hypothesis and that use of higher quality energy sources reduces total energy use, ceteris paribus. Income elasticities of fuel use are small. Additionally, we demonstrate that household size, stove ownership, and season influence energy choices. However, the effects of improved stoves are small and not consistent across the villages.     

Available friction of ladder shoes and slip potential for climbing on a straight ladder

Straight ladder accidents are a major safety problem. As a leading cause of injuries involving straight ladders, slips at the ladder base occur when the required friction exceeds the available friction at the ladder shoe and floor interface. The objectives of this experiment were to measure the available friction at the base of a portable straight ladder in contact with a floor and to estimate the slip potential of the ladder. The results of friction measurements indicated that the measured friction coefficient on the oily surfaces differed among the six commercially available ladder shoes evaluated. A statistical model was used to compare the available friction results from the current study with the friction requirements under different climbing conditions from a previous study based on their stochastic distributions to estimate the slip potential at the base of the ladder. The results showed that different climbing conditions used in the previous study could be supported by available friction on dry surfaces. However, when the ladder was put onto oily surfaces, resulting in a significant reduction in the available friction due to contamination, slip potential was significantly increased.     

A structured overview on the use of computational simulators for teaching statistical methods

Modern technology is affecting what is taught and how statistics is taught. Computer intensive methods like bootstrapping, generalized regression, coordinate exchange algorithms and computer experiment emulators are now part of the statistical toolkit. In parallel with these new methods and tools, a similar evolution appears in statistical education. Simulators offer opportunities for hands-on experience in the classroom, bridging the gap between theory and practice. In this article, we map a wide range of simulation based tools used in teaching statistical methods, putting them in the context of a quality ladder representing various maturity levels of organizations and course level sophistication. The mapping is designed to help educators assess and integrate options related to the incorporation of simulators as teaching aids in an educational and pedagogical roadmap. The mapping is applied to specific simulation products but provides a general framework that can be expanded and used in a generic way.     

地铁不均匀沉降地段的轨道类型比选分析

简要总结了地铁不均匀沉降易发生的地段、原因及不利影响,对有砟轨道、普通无砟轨道、钢弹簧浮置板、隔振垫浮置板及梯形轨枕轨道等常用轨道类型对不均匀沉降的适应性和相关技术特点进行了全面分析,梯形轨枕在自身抗弯能力、空吊的检测和整治方便性、排水、施工速度、铺设精度等方面均具有优势,对不均匀沉降的适应性最好。     

充放储一体站并网的多级阶梯电压控制分区方法

针对电动汽车充放储一体站并网带来的电压问题以及电压控制分区方法的不足,提出一种一体站并网的多级阶梯电压控制分区方法。在定义无功源控制的电气距离和评价分区质量的加权社团结构(community structure,CS)多目标模块度指标的基础上,多级阶梯电压控制分区方法分降维聚类、分裂凝聚、还原调整3级进行最优分区。在分区中结合电网运行状态,对一体站功能行为进行多场景优化,根据场景概率计算无功期望。算例采用 IEEE39节点系统对一体站并网进行电压控制分区,验证了方法的合理性和正定性,反映出一体站并网对分区带来的影响;同时采用 IEEE118节点系统进行电压控制分区,验证了方法应用在大系统中的合理性和高效性。     

Temburong Bridge,Brunei – Design of two cable stayed bridges

The Temburong Bridge Project is a 30 km long dual two‐lane highway crossing over the Brunei Bay. It will connect the relatively isolated Brunei district of Temburong to the other three Brunei districts. The main objective of the project is to stimulate economic growth in the Temburong region by connecting it to the country's airport and ports. The alignment crosses two navigation channels resulting in the need for two cable stayed bridges – the Brunei Channel Bridge (145 m main span) and the Eastern Channel Bridge (260 m main span). The design of these cable stayed bridges is one of the first applications of the Eurocode to a fully concrete cable stayed bridge. Both cable stayed bridges draw on strong Islamic architectural influences from the region to form a tower shape that is unique and instantly recognisable. Temburong Brücke, Brunei – Entwurf von zwei Schrägkabelbrücken Die Temburong Brücke ist eine 30 km lange Verbindung über die Brunei Bucht mit zwei Richtungsfahrbahnen mit je zwei Fahrstreifen. Sie wird den relativ isolierten Distrikt Temburong mit den anderen drei Distrikten Bruneis verbinden. Hauptanliegen des Projekts ist die Stimulierung von ökonomischem Wachstum in der Temburong Region, indem sie an den Flughafen und Seehafen des Landes angebunden wird. Die Trassierung erfordert die Überquerung zweier Schiffahrtsrouten. Dies wird mit der Anordnung zweier Schrägkabelbrücken ermöglicht, der Brunei Channel Brücke (145 m Hauptspannweite) und der Eastern Channel Brücke (260 m Hauptspannweite). Die Bemessung der beiden Brücken stellt eine der ersten Anwendungen des Eurocode auf Schrägkabelbrücken mit Betonüberbau dar. Optisch sind die beiden Brücken geprägt von der islamischen Architektur der Umgebung, die Pylonform ist ein besonderes Erkennungsmerkmal der Brücken.     

高石梯构造钻井技术研究与应用

高石梯构造位于乐山-龙女寺古隆起区,以震旦系灯影组及上覆寒武系储层为目的层,地层极为复杂,易塌、易漏、石膏层多、地层压力梯度变化大、可钻性差等,钻井速度慢。为了攻克提速问题,分析了本构造的地层特性和难点,优化井身结构设计和钻具组合,优选钻头,采用了螺杆+PDC复合钻井、液动冲击钻井、顶部驱动等工艺技术。本文研究了近几年在高石梯构造上相应工艺技术的运用情况,进行实用性对比分析,总结出了一套高石梯构造的钻井提速技术,通过在高石17井、高石7井等的应用,在防喷防塌防卡和安全提速上效果明显。     

Transition Motion from Ladder Climbing to Brachiation with Optimal Load-Allocation Control

Abstract

This paper describes the transition motion from ladder climbing to brachiation for a multi-locomotion robot (MLR). The MLR has versatile modes of locomotion, such as biped walking, quadruped walking, brachiation and ladder climbing. The transition is a challenging motion, because the environmental boundaries change and the robot has to switch the form of its locomotion depending on its surroundings, situations and purposes. The robot supports itself with three end-effectors that maintain its stability, while one hand transfers from a rung on the vertical ladder to a new rung behind the robot for brachiation. A closed kinematic chain is formed by the robot links and the ladder. In this case, if the number of position-controlled active joints is greater than the number of the chain’s degrees of freedom, an internal stress appears because of unavoidable position errors. The huge internal stress may lead some motors to become overloaded. Since the safety of each motor is very important for a serial-link robot, a load-allocation algorithm is proposed to balance the loads of the joint motors. The algorithm is verified through experiments.     

一种用Atmel89c2051仿真PLC控制的方法

本文提出了一种新的用Atmel89c2051仿真PLC控制的方法,允许用户先按梯形图对控制对象编程,这对继电器控制较为熟悉的电气技术人员来说提供了方便。而且,用此方法已经成功做成专用的功能电路模块。由于该仿真电路板价格低廉并具有柔性,可以被开发成产品,也十分适合于PLC控制的演示实验。     

Neurovision-based logic control of an experimental manufacturing plant using neural net le-net5 and automation Petri nets

In this paper, Petri nets and neural networks are used together in the development of an intelligent logic controller for an experimental manufacturing plant to provide the flexibility and intelligence required from this type of dynamic systems. In the experimental setup, among deformed and good parts to be processed, there are four different part types to be recognised and selected. To distinguish the correct part types, a convolutional neural net le-net5 based on-line image recognition system is established. Then, the necessary information to be used within the logic control system is produced by this on-line image recognition system. Using the information about the correct part types and Automation Petri nets, a logic control system is designed. To convert the resulting Automation Petri net model of the controller into the related ladder logic diagram (LLD), the token passing logic (TPL) method is used. Finally, the implementation of the control logic as an LDD for the real time control of the manufacturing system is accomplished by using a commercial programmable logic controller (PLC).