DF4D型机车在役车轴超声波探伤方法探讨

分析了DF4D型机车在役车轴疲劳裂纹产生的原因,介绍了车轴疲劳断裂过程。根据疲劳裂纹的特点确定了探伤条件,通过选择正确的探头角度、制作实物试块而明确提出了超声波探伤方法,并介绍了车轴疲劳裂纹波形特点和疲劳裂纹定量的影响因素。     

DF4D型机车在役车轴超声波探伤方法探讨

分析了DF4D型机车在役车轴疲劳裂纹产生的原因,介绍了车轴疲劳断裂过程.根据疲劳裂纹的特点确定了探伤条件,通过选择正确的探头角度、制作实物试块而明确提出了超声波探伤方法,并介绍了车轴疲劳裂纹波形特点和疲劳裂纹定量的影响因素.     

机车车轴多通道超声波探伤系统

简要介绍了机车车轴受力状况和目前采取的探伤手段。对机车车轴采用多通道超声波探伤系统进行了探讨。其结果对机车车轴,尤其是对空心轴结构的快速机车车轴探伤的效率、精度、可靠性具有一定的意义。     

东风4A、4B型机车车轴的超声波探伤

中修时东风4A、4B型机车车轴疲劳裂纹的超声波探伤用三种方法:透声检查、小角度纵波探伤和斜探头横波探伤.介绍了它们在探伤时所出现的各种情况,并提出了改进建议.     

车轴探伤方法的探讨

针对车轴探伤中几种常用的探伤方法,分别对其检测方式、不同的特点及它们的不足之处进行了分析研究,并提出了改进建议,以提高探伤质量.     

钢材检测中的超声波自动化探伤研究

中国是世界上高铁发展最快,集成能力最强、运营速度最高的国家.随着轨道车辆行驶速度提高,对零部件加工质量要求不断提高.目前我国超声波探伤自动化程度低,影响大规模实现车轴自主生产.超声波探伤实施方式分为采用便携式超声波探伤仪,手持超声波探头在材料表面移动,完成缺陷判别;采用大型自动化探伤设备,使探头相对材料旋转,完成对材料...     

在役联箱角接头超声波探伤系统的研发

为了有效检出在役锅炉联箱管座角接头中的缺陷 ,针对管座角焊缝主、支管两侧探伤的缺陷信号识别和缺陷定位定量困难等技术问题 ,研究开发出超声波探伤系统。系统能够对各种规格和型式的联箱角接头探伤提供全程指导和专家咨询 ,并能自动评定缺陷和生成报告。系统采用VisualBasic 6.0语言设计开发 ,人机界面友好 ,操作方便。     

对16V240ZJB型柴油机气缸盖横臂导杆超声波探伤的探讨

对16V240ZJB型柴油机气缸盖上横臂导杆探伤问题、所使用的专用探头、探伤灵敏度及缺陷当量的定量、探伤测量方法进行了介绍.对柳州机务段1996～1998年因横臂导杆裂损形成的临修进行了统计.最后提出了几点建议.     

一种超声波探伤近距离缺陷定量方法的可行性研究

针对目前应用比较广泛的超声波探伤近距离缺陷定量一直沿用效率比较低下的当量试块比较法的不足，通过一系列的试验，对固体介质中超声波近距离声场压的分布情况进行了研究，并对其和理论声场压分布不同的原因进行了分析，论证了一种新的近距离缺陷定量方法的可行性，力图为寻求新的超声波近距离缺陷定量方法奠定基础。     

高速机车车辆车轴的疲劳设计

从提高高速机车车辆车轴的疲劳寿命出发,系统介绍了国外主要高速动车车轴的材质选择、强度计算、结构特点、表面处理、维修周期、检修内容以及超声波探伤技术的改进等问题,并通过对其结构参数、疲劳极限应力、表层残余应力及维修规程的分析,说明了这些车轴之所以具有高疲劳可靠性的原理。     

火电厂节能工作浅析

本文探讨了火电厂节能基本程序和工作方法,分析节能工作要从基础工作、技术创新、设备整治、燃烧管理等方面入手的论述.     

浅析磨合期汽车的使用

如何合理使用磨合期的汽车，使其摩擦机件的磨损量能够平稳、均匀地磨合而不至于过度磨损，对汽车实际使用寿命有着重要的意义。从机器磨合期的特点和磨损机理出发，对汽车磨合期如何正确使用进行了有实际意义的探讨。     

Geothermal energy in agriculture in Yugoslavia

SFR Yugoslavia has natural hot water springs practically all over its territory, indicating the presence of geothermal reservoirs underground. There is no final estimate of how much energy can be expected from this new resource, except for figures based on the results of studies and investigations.The first use of geothermal energy in Yugoslavia in numerous spas dates back to the 19th century. Some remarkable examples of central heating are known, but the most widespread use is in agriculture (in greenhouse heating, farm heating and drying of agricultural products).     

Energy conservation measures in an institutional building in sub-tropical climate in Australia

In this study, various energy conservation measures (ECMs) on heating, ventilating and air conditioning (HVAC) and lighting systems for a four-storied institutional building in sub-tropical (hot and humid climate) Queensland, Australia are evaluated using the simulation software called DesignBuilder (DB). Base case scenario of energy consumption profiles of existing systems are analysed and simulated first then, the simulated results are verified by on-site measured data. Three categories of ECMs, namely major investment ECMs (variable air volume (VAV) systems against constant air volume (CAV); and low coefficient of performance (COP) chillers against high COP chillers); minor investment ECMs (photo electric dimming control system against general lighting, and double glazed low emittance windows against single-glazed windows) and zero investment ECMs (reset heating and cooling set point temperatures) are evaluated. It is found that the building considered in this study can save up to 41.87% energy without compromising occupancies thermal comfort by implementing the above mentioned ECMs into the existing system.     

Uncertainties in decarbonising heat in the UK

Heating is arguably one of the most difficult sectors to decarbonise in the UK's energy system. Meeting the 80% greenhouse gas emission reduction target by 2050 is likely to require that heat related emissions of CO₂ from buildings are near zero by 2050, and there is a 70% reduction in emissions from industry (from 1990 levels). Though it is clear that the use of the natural gas network will reduce over time, recent modelling suggests a limited residual role for gas by 2050 to help meet peaks in heat demand. High levels of uncertainty about the way in which heat will be decarbonised present a number of challenges to policy makers. This paper will explore the risks and uncertainties associated with the transition to a low carbon heat system in the UK as outlined by the 4th carbon budget review. The potential impact of key uncertainties on the levelised costs of heat technologies and the development of energy networks are explored using a sensitivity analysis approach. Policy changes required to decarbonise the heat sector are also examined.     

Viscous heating in liquid flows in micro-channels

Many experimental works on forced convection through micro-channels evidenced that when the hydraulic diameter is less than 1 mm, conventional theory can no longer be considered as suitable to predict the pressure drop and convective heat transfer coefficients. This conclusion seemed valid for both gas and liquid flows. Sometimes the authors justified this claim by invoking “new” micro-effects. On the contrary, in this paper the explanation of the experimental results obtained for micro-channels in terms of friction factors will be researched inside the conventional theory (Navier-Stokes equations). In particular, this paper will focus on the role of viscous heating in fluids flowing through micro-channels. A criterion will be presented to draw the limit of significance for viscous dissipation effects in micro-channel flows. The role of the cross-sectional geometry on viscous dissipation will be highlighted and the minimum Reynolds number for which viscous dissipation effects can no longer be neglected will be calculated as a function of the hydraulic diameter and of the micro-channel geometry for different fluids. It will be demonstrated how viscous effects can explain some experimental results on the Poiseuille numbers in micro-channels, which recently appeared in the open literature.     

Solar drying in sludge management in Turkey

Two main wastewater treatment plants in Bursa city in Turkey will start to operate and produce at least 27,000 tons of dry solids per year by the end of 2006. The purpose of this study was to investigate an economical solution to the sludge management problem that Bursa city would encounter. The general trend in Turkey is mechanical dewatering to obtain a dry solid (DS) content of 20%, and liming the mechanically dewatered sludge to reach the legal landfilling requirement, 35% DS content. This study recommends limited liming & solar drying as an alternative to only-liming the mechanically dewatered sludge. Open and covered solar sludge drying plants were constructed in pilot scale for experimental purposes. Dry solids and climatic conditions were constantly measured. Faecal coliform reduction was also monitored. The specially designed covered solar drying plant proved to be more efficient than the open plant in terms of drying and faecal coliform reduction. It was found that, if the limited liming & solar drying method was applied after mechanical dewatering instead of only-liming method, the total amount of the sludge to be disposed would be reduced by approximately 40%. This would lead to a reduction in the transportation, handling, and landfilling costs. The covered drying system would amortize itself in 4 years.     

Electoral cycles in electricity losses in India

A third of electricity in India is lost each year, where losses refer to power that is supplied but not billed. Utilizing data from the power corporation of Uttar Pradesh, India's most populous state, we study the politics of electricity losses. Examining annual data over four decades, we document that UP's electricity losses tend to increase in periods immediately prior to state assembly elections. Drawing upon geographically disaggregated data for the period 2000–09, we observe higher line losses just prior to the 2002 and 2007 state elections. Our analysis shows that the incumbent party was more likely to retain the assembly seat as line losses in the locality increased. We interpret these results as corroboration that political parties deliberately redirect electricity to flat rate and unbilled users in a context of chronically inadequate supply. Political factors appear to affect line losses in ways that technical and economic factors alone cannot explain.     

Energy consumption in rural transportation in India

Energy consumption in rural transportation has been computed, taking into account the energy embodied in vehicles or bullocks, as well as the fuels or feeds and food (of operators). Bullock cart transport consumes over four times more energy than vehicles. However, animal transport will continue to be preferred because of its availability.