bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Design, Manufacture and Assembly of the Wheelset for the British Rail Class 91, 25 Kv, 225 Km/H Locomotive
Authors: Broom M L , Smart G W 
Published: February 2007

The British Railways Board (BRB) Class 91 is a 225 km/h, 25 kV locomotive for use on the East and West Coast main line routes. This paper details the design and manufacturing processes applied to the Class 91 locomotive wheelset. Reference is made to many unusual and novel aspects of the design and manufacture. The principal design requirement was to achieve a low effective ‘unsprung’ mass of 1700 kg in order to limit damage to the track to acceptable maintenance levels. This was achieved by using a hollow axle, mounting the motors on the body, the gearbox on the bogie and by careful attention to the detail design of the component parts. The specified requirement characteristics and design data are given along with the design processes used. Problems encountered during both the design and manufacturing phases are highlighted along with the measures adopted to overcome them. The manufacture of the wheels and axle and the assembly of the complete wheelset are described in detail. Of particular note is the use of purpose-built assembly and handling jigs. Finally a brief account of the post build service experience is included.
The Design and Commissioning of an Acoustic Liner for Propeller Noise Testing in the ARA Transonic Wind Tunnel
Authors: Wood M E , Newman D A 
Published: February 2007

An acoustic liner has been designed and manufactured for use in the ARA transonic wind tunnel to provide an acoustically acceptable environment for propeller noise testing up to high subsonic Mach number. Details of the aerodynamic design and development are presented and calibration of the liner with propeller model support systems is included. It is shown how the design of the acoustic treatment was aided by the use of a theoretical model for the tunnel reverberant field. An acoustic development programme was undertaken involving horn tests to improve the quality of the liner. The success of this is demonstrated by propeller noise results. These results also provided the basis for definition of the practical acoustic test regime of the ARA lined tunnel suitable for the accurate measurement of propeller noise.
A Numerical Model of the Load Transmission in the Tibio-Femoral Contact Area
Authors: Schreppers G J M A , Sauren A A H J , Huson A 
Published: February 2007

An axisymmetric finite element model is applied to the analysis of the force transmission between the tibia-meniscus-femur. The model assumes linear elastic material properties, static loading and sliding contact between the components. The study explores the effects of (a) tibial surface geometry (plane, convex, concave), (b) inclusion of soft layers on the bony components and (c) anisotropic properties of the meniscus. When soft layers are absent, tibial surface geometry is found to affect the total axial stiffness of the model, the radial displacement of the meniscal ring as well as the meniscal share in load transmission. Inclusion of soft layers yields qualitatively the same results for the different geometries, under the understanding that axial stiffness decreases while meniscal radial displacements increase. However, the effect of tibial geometry on the meniscal share in load transmission almost disappears as soon as soft layers are applied, while at the same time a significant increase of this share is observed. Increased circumferential stiffness of the meniscal ring raises this share even more.
Influence of the Varus—Valgus Instability on the Contact of the Femoro-Tibial Joint
Authors: Inaba H I , Arai M A , Watanabe W W 
Published: February 2007

The varus-valgus instability of the knee joint is mainly due to ruptured or lax collateral ligaments. The purpose of this investigation was to study the influence of the varus-valgus instability on the contact pressures of the femoro-tibial joint. Six fresh knee specimens of human cadavers were tested to measure the contact pressure on the tibia plateau of the knee joint at varus or valgus alignment under various loads and at full extension. Pressure transducers and Bourdon tube pressure gauges were used simultaneously for recording pressure. At neutral alignment of the knee with the menisci intact, the peak pressure increased linearly with forces up to 4 MPa. With increasing varus alignment, the peak contact pressure on the medial plateau not covered by the menisci increased up to a maximum of 7.3 MPa at 5° varus, and at 5° valgus, the peak pressure on the lateral plateau was 7.8 MPa. After total meniscectomy, the contact pressure increased up to a maximum of 7.4 MPa at a force of 2700 N. With increasing varus alignment, the contact pressure on the medial plateau increased to 8.1 MPa at 5° varus and on the lateral plateau 9.2 MPa at 5° valgus.
The Influence of Bone and Bone Cement Debris on Counterface Roughness in Sliding Wear Tests of Ultra-High Molecular Weight Polyethylene on Stainless Steel
Authors: Caravia L , Dowson D , Fisher J , Jobbins B 
Published: February 2007

Studies of explanted hip prostheses have shown high wear rates of ultra-high molecular weight polyethylene (UHMWPE) acetabular cups and roughening of the surface of the metallic femoral head. Bone and bone cement particles have also been found in the articulating surfaces of some joints. It has been proposed that bone or bone cement particles may cause scratching and deterioration in the surface finish of metallic femoral heads, thus producing increased wear rates and excessive amounts of wear debris. Sliding wear tests of UHMWPE pins on stainless steel have been performed with particles of different types of bone and bone cement added. Damage to the stainless steel counterface and the motion of particles through the interface have been studied. Particles of bone cement with zirconium and barium sulphate additives and particles of cortical bone scratched the stainless steel counterface. The cement particles with zirconium additive produced significantly greater surface damage. The number of particles entering the contact and embedding in the UHMWPE pin was dependent on particle size and geometry, surface roughness and contact stress. Particles are likely to cause surface roughening and increased wear rates in artificial joints.
Acoustic Emission from Trabecular Bone during Mechanical Testing: The Effect of Osteoporosis and Osteoarthritis
Authors: Leichter I , Bivas A , Margulies J Y , Roman I , Simkin A 
Published: February 2007

This study examines the relation between the nature of acoustic emission signals emitted from cancellous bone under compression and the mechanical properties of the tissue. The examined bone specimens were taken from 12 normal, 31 osteoporotic and six osteoarthritic femoral heads. The mechanical behaviour of the osteoporotic bone specimens was found to be significantly different from that of the normal specimens both in the pre-yield and post-yield ranges. In the osteoarthritic bones only the elastic behaviour was significantly different. The rates of acoustic events before yield and beyond it were found to be significantly higher both in the osteoporotic and osteoarthritic bone specimens. The average peak amplitude of the signals was also significantly higher in the diseased bones. Stepwise regression analysis showed that a combination of the acoustic emission parameters could significantly predict some mechanical properties of the bone. The energy absorbed during compression and the ultimate compressive stress of the specimens could be estimated from the rate of pre-yield acoustic events, the average amplitude of the signals and the rate of post-yield events. However, the explanation power of the acoustic emission parameters was only moderate. The nature of acoustic emission signals was thus demonstrated to be a potential tool for assessing bone quality.
Measurement of Pressures in the Nucleus and within the Annulus of the Human Spinal Disc: Due to Extreme Loading
Authors: Ranu H S 
Published: February 2007

Specially developed intervertebral and intradiscal pressure transducers are used to map the pressures in the nucleus pulposus and within the annulus fibrosus of the human spinal discs, to the point of fracture of the segmental units. The results show that for normal discs, pressures in the nucleus and in the annulus are linearly related to each other and to the applied compressive loads. Mechanical strains which develop around the periphery ofthe vertebral body are also linear with the applied compressive loads, when the partial vertebral column is loaded to the point of bony fracture. Failure of the intervertebral discs at the point of fracture occurred through the vertebral body endplates and the annulus fibrosus remained intact.
Variations of Gait Parameters in Duchenne Muscular Dystrophy
Authors: Khodadadeh S , McClelland M R , Patrick J H 
Published: February 2007

The gait parameters (speed, stride length and cadence) of nine boys with Duchenne muscular dystrophy were compared with those of 21 normal boys in the same age range. Differences found were due to the altered ability to control their dynamic state and, to a lesser extent, physical limitations of joint range. This simple method of quantifying gait is proposed as a way in which progression or response to treatment in muscular dystrophy might be monitored. The information obtained may alert the clinician to the fact that the progressive muscle weakness and joint contractures have begun to cause compensatory mechanisms during walking to fail. It is also useful to obtain information on gait in clinical treatment trials as there are very few reliable methods for testing function in muscular dystrophy.
An Integrating Role for the Microcomputer in Engineering Education
Authors: Heikal M R , Peeling K A 
Published: February 2007

This paper discusses the various ways in which computers are used in engineering teaching. The relative merits of each area of application are also discussed and potential pitfalls are highlighted. It then shows how these areas can be interlinked to provide a comprehensive learning environment. The requirements and benefits of this integrated approach are also presented and the problems and constraints which limit its wider application are discussed in the light of experience of a pilot scheme in the area of thermofluids. The paper also proposes possible ways of overcoming these problems.
The Design of Experiments for Engineering Studies with Particular Reference to Thermofluids
Authors: Wilkie D 
Published: February 2007

Studies in engineering science, including thermofluids, almost invariably neglect well-established methods of designing experiments and analysing experimental data, thereby forfeiting efficiency and incurring the risk of drawing false conclusions on effects and errors. The methods, which are compared with the classical approach, are simply described and are illustrated by relevant examples chosen to aid undergraduate teaching. The ideas have application to university laboratory experiments, to research and to quality assurance in industry.
Environmental Considerations for UK Steam Plant in the 1990s—A Manufacturer's View
Authors: Trimm V D 
Published: February 2007

The international and global consequences of polluting emissions from power generating plants have led to increased political pressure for corrective action. This in turn has prompted considerable effort to develop new technologies that are economical in the production and use of energy, and cause minimum pollution. Political factors such as privatization, nuclear policy and government views on strategic diversity of supply further complicate the environmental issues facing the manufacturer in deciding a business strategy. This paper takes a wide-ranging view of these issues, presenting data in a simplified form to help in the decision-making process. The major pollutants from power generation are the acid rain gases (SO2, NOx, HCl), secondary liquid and solid wastes (gypsum etc.) and greenhouse gases (CO2). These are summarized in tables showing their origin, effect and means of control. Control of these pollutants can be effected by (a) limiting the demand for energy, (b) selection of non-polluting sources (for example tidal, wind), (c) switching fuels (for example gas, low-sulphur coal), (d) a choice of combustion and clean-up technology. Each of these major options is reviewed to assess their potential benefits and also their limitations. The vulnerability of some options to political action is noted. The technology options are considered in more detail to enable comparisons to be made. The presentation of data in summary form is designed to simplify the cross-reference between each technology and its pollution impact. Development time-scales and commercial issues are also taken into account. In this very complex picture there are not many stable elements on which the manufacturer can build a business plan for short-term equipment supply or longer-term investment in technology. However, this paper gives some perspective to the issues, so that the interaction between technical solutions and economic and political factors can be given due consideration.
A Comprehensive Classification of Combined Cycle and Cogeneration Plant: Part 2: Introducing the Integrated Steam Cycle in Practice
Authors: Taft M 
Published: February 2007

A single equation for plant thermal efficiency was derived in Part 1 of this paper. This equation was based upon component efficiencies and the ratio of steam plant size to gas turbine size. The analysis resulted in a unique map being graphically presented. The map covered the whole steam range from power generation through to combined heat and power, in association with gas turbines. Understanding of the map leads to recognition of an underutilized area. Part 2 of this paper explores the type of plant within that area of classification. The gas turbine is normally integrated with the main steam boiler. The natural tendency is to fully after-fire the gas turbine's exhaust. The resulting plant then overshoots the area of the map in question. Instead, the unfired combined cycle plant may be integrated with a conventional boiler and back-pressure turbine. The correct steam turbine-gas turbine size ratio must be chosen. This particular option is suitable for a medium-scale power plant. Conversely, a practical example is given of how a gas turbine and waste heat boiler may be introduced part-way along a large power station's main steam turbine. The integration is achieved in the steam cycle and not at the main boiler. This approach allows low-risk, low capital cost, simple repowering of large power stations. The concept of the integrated steam cycle is developed by this paper first considering turbines and boilers as components in isolation. Next the characteristics of primary combinations of those components are considered as ‘building blocks’, each with an inherent performance and cost. Finally, the required practical blend of standard components is derived by concentrating on the predetermined size ratio. The end result is simple and, with the benefit of hindsight, may seem obvious. Nonetheless, the integrated steam cycle offers a compromise between combined cycle and conventional steam plant, with favourable performance, cost and environmental impact. Examples are given based on coal-fired or heavy-fuel-oil-fired combined cycle plant, integrating conventional boiler, gas turbine plus unfired boiler and steam turbine. The data are based on real equipment, which is either at existing UK installations or plant of known performance.
An Equivalent Reduced Modelling Method and its Application to Shaft—Blade Coupled Torsional Vibration Analysis of a Turbine—Generator Set
Authors: Okabe A , Otawara Y , Kaneko R , Matsushita O , Namura K 
Published: February 2007

A coupled vibrating system (for example turbine-generator set), consisting of a main system (for example shaft system) and a sub-system (for example blade system) which are connected at bonding points (for example the centre boss of a blade), is equivalently reduced to a model suitable for analysis. According to this modelling technique, the eigenvalue analysis of the uncoupled flexible sub-system is done first under the assumption of the fixed bonding point. Then, an equivalent mass-spring system is produced for each eigenmode of the uncoupled subsystem. In this way, the main system plus the additional equivalent mass-spring model of the sub-system is combined into a global system model. This modelling technique is applied to the shaft-blade coupled vibration problems in an actual turbine-generator set and its effectiveness is provided with experimental test results.
Shut-off Head of Centrifugal Pumps and Fans
Authors: Frost T H , Nilsen E 
Published: February 2007

A simple model is proposed for estimating the contribution of the volute to the shut-off head of a centrifugal pump or fan. The model is based on an assumed linear distribution of tangential velocity in the plane of the cut water which satisfies approximately the continuity condition of zero net flow into the outlet duct. The contribution of the impeller is assumed to be that given by a solid body rotation at the angular velocity of the pump from the bore of the inlet duct to the impeller tip. The simple radial equilibrium equation is then used to calculate the static head rise in both the impeller and volute. The resultant prediction of shut-off head, which only requires as input the angular velocity and four radii, has been compared to test data on various pump series made available by courtesy of two European manufacturers. In all of the series the impeller diameter has been varied between 100 and 90–80 per cent of its design value and has been tested in the design volute. Over the series the predicted shut-off head coefficient (gH30/U22) was between 1 and 6 per cent lower than the measured values, which themselves varied over the range 0.5–0.6. The predicted contribution from the volute varied typically between 20 and 30 per cent of the total head rise over the range of impeller size, emphasizing the significant contribution from the volute and its dependence on the impeller/volute geometry. Since a review of the available literature did not show any previous work of a fully consistent nature on this topic the proposed model as described in detail below is offered as a fairly accurate prediction technique for design purposes.
On the Role of the Harmonic Mean Isentropic Exponent in the Analysis of the Closed-Cycle Gas Turbine
Authors: Woods W A 
Published: February 2007

This technical note presents a development of the perfect gas analysis of the simple, closed-cycle, gas turbine reported by Hawthorne and Davis. Some comments on perfect and semi-perfect gases are included for clarification. The new analysis takes account of the variation of specific heats of the working fluid by treating the flow through the compressor and the flow through the turbine as different perfect gases. An analytical expression is derived for the pressure ratio corresponding to maximum power. This expression is shown to be the same as that derived previously, except that the isentropic exponent has to be replaced by the harmonic mean of those used for the compressor and the turbine. The note shows that the new method leads to significantly higher pressure ratios for the maximum power.
Analysis of Bi-Arm Robots for Applications in Manufacturing Industry
Authors: Buckingham R O , Brett P N , Khodabandehloo K 
Published: February 2007

Within manufacturing industry many assembly and materials handling tasks are labour intensive and do not lend themselves to the application of dedicated machinery carrying out specific repetitive parts of the process. Automation of these processes will require adaptive machinery able to respond to variations in product size, orientation, mechanical properties and the position in which the task is carried out. The potential of intelligent bi-arm robot systems in these areas is discussed in relation to a number of specific bi-arm robot tasks. The paper also discusses the design of bi-arm systems with reference to a suite of simulation programs for the analysis of workspace quality of branched, serial and closed chain robot configurations. The structure of the program enables the analysis of any robot configuration and provides the means of assessing the strategies required for robot control such as clash detection and trajectory planning.
A General Three-Dimensional Finite Element Approach for Porous and Dense Metal-Forming Processes
Authors: Marques M J M Barata , Martins P A F 
Published: February 2007

The rigid plastic finite element flow formulation based on the Doraivelu et al., constitutive equations is described. Applications to the three-dimensional compression of rectangular blocks made from dense and porous materials are presented. Modification on the ‘arc tangent’ friction model initially proposed by Chen and Kobayashi in order to take into account these constitutive equations is also discussed. A three-dimensional finite element programme based on a generalization of the Doraivelu et al., model to include the plastic deformation of dense materials was developed. Numerical tests performed on the simulation of fully dense materials using this programme show a good agreement with the results obtained with other programmes based on the Levy-Mises constitutive equations. Theoretical predictions for the simulation of the compression of rectangular blocks made from a porous material are also presented.
Towards Improving the Properties of Plaster Moulds and Castings
Authors: Brevick J R , Davis J W , Dincher C 
Published: February 2007

The plaster moulding process is commonly used for casting prototypes of aluminium components designed for subsequent production by die casting. Plaster moulded prototype castings possess dimensional tolerances and surface quality comparable to die castings, but without the high tooling costs and lead times. Unfortunately, the mechanical properties of plaster castings are significantly inferior to their die cast counterparts. This is due primarily to the low thermal conductivity of plaster which extends casting solidification time significantly compared to die or even sand casting processes. Long solidification times result in large grained castings demonstrating low strength and hardness. This work is an experimental investigation into the effects of various levels of silica sand and carbon fibre additions on the properties of foaming plaster moulds and associated aluminium castings. Data and statistical analyses are presented and conclusions drawn regarding the wet and dry strength of plaster moulds as a function of sand and carbon fibre content. Likewise, conclusions regarding the associated casting characteristics such as surface finish, solidification time, hardness and tensile strength are presented. The effectiveness of silica sand and carbon fibre additions with respect to improving the properties of plaster moulded prototype castings is also discussed.