Internal energy flow analysis within a single effect sorption heat pump

The knowledge of the characteristics of unused, excess and untapped exergy allows a thorough analysis of internal energy flows distribution within a sorption heat pump. It can be applied to any system based on gas–liquid absorption, adsorption or solid–gas reaction as well as to any process based on the internal recycling of the energy flux. It can also be applied for the case of a simple effect ideal machine, in particular in the definition of processes where the COP is larger than 2: the levels at which the initial exergy is downgraded on the one hand, as well as, the upgraded excess exergy produced on the other allows the designer to make a judicious choice of a system.     

An analysis of designing for quality in the automotive industry

The paper is based on the authors' experiences in devising and conducting continuing education courses on Designing for Quality for design, development and manufacturing engineers in a large automotive company. Participants in the courses brought forward a wide range of quality problems encountered in their day-to-day professional activities. Methods for classifying and defining these problems are developed as a prelude to examination of the product development process and its management to fulfil quality objectives. The technique of quality function deployment which has recently received wide publicity in automotive engineering is investigated in the context of established design theory. Conclusions are drawn relating to the practice of engineering design in industry and the need for the effective dissemination of the work of design researchers.     

An analysis of peristaltic transport for flow of a Jeffrey fluid

Summary The peristaltic mechanism of a Jeffrey fluid in a circular tube is investigated. The rheological effects and compressibility of the fluid are taken into account. The modeled equations are solved using perturbation technique when the ratio of the wave amplitude to the radius of the pore is small. In the second order approximation, a net flow due to a travelling wave is obtained and effects of Reynolds number, relaxation and retardation times, compressibility of the fluid and tube radius are studied. It is noticed that for the Jeffrey fluid the back flow only occurs for large values of the relaxation time and small values of the retardation time (less than 10 in the present analysis). Another interesting observation is that oscillatory behavior of the net flow rate in the Jeffrey fluid is less than that of a Maxwell fluid. Several results of other fluid models can be deduced as the limiting cases of our situation.     

An analysis of incidents involving major hazards in the chemical industry

Some problems associated with assessing the safety performance of the Chemical Industry are discussed. Over 170 major incidents involving chemical plants world-wide have been collated and analysed for trends.The number of major incidents and the total number of people killed by such events are rising exponentially. The trend to increased size and complexity of installations does not appear to have led to more severe incidents in terms of deaths, although the analysis has limitations. Financial costs of major incidents are increasing at a rate way ahead of inflation but there is no correlation between these costs and the number of fatalities arising from these incidents. All this, together with additional considerations identified, is considered ample justification for the special attention directed at the study of Major Hazard installations.     

An energy analysis of crack initiation and arrest in epoxy

The objective of this work is to study fracture processes such as crack initiation and arrest in epoxy. A compact tension specimen with displacement-controlled loading is employed to observe multiple crack initiations and arrests. The energy release rate at crack initiation is significantly higher than that at crack arrest, as has been observed elsewhere. In this study the difference between these energy release rates is found to depend on specimen size (scale effect), and is quantitatively related to the fracture surface morphology. The scale effect, similar to that in strength theory, is conventionally attributed to the statistics of defects which control the fracture process. Triangular shaped ripples, deltoids, are formed on the fracture surface of the epoxy during the slow sub-critical crack growth, prior to the smooth mirror-like surface characteristic of fast cracks. The deltoids are complimentary on the two crack faces which excludes any inelastic deformation from consideration. The deltoids are analogous to the ripples created on a river surface downstream from a small obstacle. However, in spite of our expectation based on this analogy and the observed scale effect, there are no defects at the apex of the deltoids detectable down to the 0.1 micron level. This suggests that the formation of deltoids during the slow process of sub-critical crack growth is an intrinsic feature of the fracture process itself, triggered by inhomogeneity of material on a sub-micron scale. This inhomogeneity may be related to a fluctuation in the cross-link density of the epoxy.     

声振系统中高频能量流分析法研究进展

能量流分析法是预测声振系统中高频动力响应的一种有效手段,该方法引入的假设条件较少,并可基于声振系统的几何模型计算随空间变化的稳态动力响应,应用上具有很大的优点。本文首先回顾了不同结构件（包括杆、梁、板及复合结构）各种波场的能量微分方程及其理论基础的发展过程,然后,针对不同类型的声振系统耦合形式,包括结构/结构耦合,结构/流体耦合及其它耦合情况,说明了基于能量流分析的耦合问题处理方法的发展,最后,说明了计算随机激励下声振系统响应的随机能量流分析法的相关研究,以及其与经典统计能量分析法间理论关系研究的进展情况。     

An analytical analysis of energy release rate in bonded composite joints in a mode I condition

A complete analytical solution of mode I strain energy release rate, G_I, was derived for bonded composite joints based on an augmented double cantilever beam (DCB) model. Good agreement was obtained between current and existing comparable theoretical solutions for this joint with a long adhesive bond. For a short bond length joint, the current solution can greatly reduce the degree of the mathematical singularity encountered in analyses of thick, short beams and avoid it entirely for thin, long beams. A correlation between the current theoretical and associated ASTM solutions was established. A bonded DCB laminate test case was conducted, and good agreement was obtained between the experimental and current theoretical results. Commentary was included regarding the tested critical strain energy release rate and the deduced critical adhesive peel stress.     

An electrical arc in a turbulent gas flow

The self-similar solution of the equations describing an axisymmetric electrical arc in a turbulent gas flow is presented.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 48, No. 2, pp. 272–278, February, 1985.     

Electrogenerated chemiluminescence detection in paper-based microfluidic sensors

This paper describes the first approach at combining paper microfluidics with electrochemiluminescent (ECL) detection. Inkjet printing is used to produce paper microfluidic substrates which are combined with screen-printed electrodes (SPEs) to create simple, cheap, disposable sensors which can be read without a traditional photodetector. The sensing mechanism is based on the orange luminescence due to the ECL reaction of tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)(3)(2+)) with certain analytes. Using a conventional photodetector, 2-(dibutylamino)ethanol (DBAE) and nicotinamide adenine dinucleotide (NADH) could be detected to levels of 0.9 μM and 72 μM, respectively. Significantly, a mobile camera phone can also be used to detect the luminescence from the sensors. By analyzing the red pixel intensity in digital images of the ECL emission, a calibration curve was constructed demonstrating that DBAE could be detected to levels of 250 μM using the phone.     

An analysis of the flow in rotating cryogenic vapour columns with a uniform axial temperature gradient

A preliminary analysis is made on the flow of nitrogen and helium vapours in the necks of rotating cryostats. Solutions for the velocity and temperature profiles are presented for fully developed flow with a uniform axial temperature gradient and are compared with experimental observations on flow in a rotating glass dewar. The flow of cold vapour is confined to an annular boundary layer with a thickness proportional to the fourth root of the rotational Rayleigh number, while a reverse flow of warm vapour is generated on the axis.     

L型耦合板相关激励下高频随机能量流分析

将板的能量流分析法应用于耦合板结构受随机激励的情形,并用无限板导纳近似有限板导纳的方法考虑了随机力的相关性对输入功率的影响。对在同一块板上受到两个相关或不相关随机力作用的L型耦合板的能量响应和功率流进行了计算,结果反映了能量密度的空间分布和功率在子结构间和内部的传递路径。两种相关激励条件下的结果对比表明,作用于所考虑位置上的随机激励间的相关性对耦合结构的能量响应及功率传递的影响很小。对该L型耦合板的响应用传统的统计能量分析法进行了求解,其结果与能量流分析法预测的主要能量场的响应基本一致,说明了考虑随机力间相关作用的能量流分析法应用的有效性。     

Boundary layer separation in a laminar supersonic flow with energy supply source

The influence of electric discharge in a supersonic gas flow on the separation of a laminar boundary layer has been studied by numerical methods. The discharge is modeled by an energy supply source with preset intensity and configuration. It is established that the behavior of flows in the system with thermally insulated and isothermally cooled walls differs in a broad range of the heat source power. The possibility of controlling the boundary layer separation is demonstrated.     

Estimation of energy consumption for body drag reduction in a supersonic flow

Comparative estimation of the drag reduction effect attained versus the required energy consumptions is made from numerical results of axisymmetric supersonic nonviscous gas flow past a blunt body with heat energy supplied to the gas in the vicinity of the symmetry axis.Translated from Inzhenerno-fizicheskii Zhurnal, Vol. 63, No. 6, pp. 659–664, December, 1992.     

Supersonic flow regimes with a pulsating laser radiation energy supply

A comparative analysis of the gas flow regimes behind the region of laser energy supply to a supersonic jet is performed depending on the laser radiation focusing conditions. A relationship established between the energy and gasdynamic parameters reveals a significant difference in the flow parameters (velocity, stagnation pressure) behind the extended and localized (point) thermal plasma sources for the identical initial conditions in a supersonic jet with the Mach numbers M=1.5–10.     

An analysis of the decline in California traffic fatalities during the energy crisis

This study attempts to assess the impact on California traffic fatalities of changes brought about by the 1974 energy crisis. Traffic fatalities are caused by a multitude of factors, but historically California fatalities have been closely related statistically to two factors. One is driving risk as measured by average fatalities per vehicle mile. The second is the amount of exposure to risk as measured by the volume of vehicle miles traveled. Based on these considerations, a projection is made of the number of fatalities that would have occurred under non-energy-crisis conditions. Estimates are then made of the impact of (1) the reduction in driving, (2) permanent daylight saving time, and (3) the reduction in speed and speed dispersion.     

纸基碳纳米管薄膜/叉指结构的超灵敏宽量程压力传感器（英文）

柔性压力传感器因其在可穿戴设备和人机交互界面中的潜在应用而备受关注.特别是在实际应用中,人们对具有高灵敏度、宽测量范围和低成本的压力传感器有很大需求.基于此,我们研制出了一种测量范围宽的超灵敏压力传感器.该传感器是以碳纳米管(CNT)均匀溶液直接喷在纸表面作为敏感材料,用光刻技术制成的叉指电极为结构.由于CNT大的比表面积、纸的多孔结构以及CNT与叉指电极有效接触的协同作用,压力传感器实现了从0到140 kPa的宽测量范围,并在15,000个测试周期内表现出良好的稳定性.对于纸基碳纳米管薄膜/叉指状结构(PCI)压力传感器,敏感材料与叉指电极之间的连接区域在较小的压力范围内占主导地位,而敏感材料的内部变化在大的压力区域起主导作用.此外PCI压力传感器不仅具有2.72 kPa-1(直到35 kPa)的高灵敏度,还可以检测小重量,如一颗绿豆(约8 Pa).当压力传感器贴附到人体表面时,可以监测生理信号,如手腕运动、脉搏跳动和语音识别.此外,压力传感器的阵列能够识别空间压力分布,有望实际应用于人机交互界面.     

Fluid flow and heat transfer analysis of Couette flow in a composite duct

Summary This paper deals with a fully developed Couette flow through a composite channel, partially filled with a clear fluid and partially with a fluid-saturated porous medium. The flow occurs because of a moving plate, which bounds the clear fluid region. The porous region is bounded by a fixed plate. Assuming that the moving plate is adiabatic, and that the fixed plate is subject to a uniform heat flux, a boundary layer solution for the velocity and temperature fields is obtained.