bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of an Image Capture and Analysis Technique for the Investigation of the Very Early Stagek of Combustion in a Lean-Burn Engine and the Detection of a Novel Early Combustion Phase Which Correlates with Subsequent Cycle Quality
Authors: Hancock M S , Belmont M R , Buckingham D J
Published: February 2007

An imaging technique has been developed which allows investigation of the development of the very earliest combustion events in a IC (internal combustion) engine. It utilizes the high-speed electronic photography capabilities of an Imacon camera enhanced by an image intensifier. The framing sequence obtained is captured via a CCD camera and framestore. Using optimally designed image filtering techniques it is possible to separate out individual dynamic regimes in these early combustion images. The ability of this technique to extract characteristic features of the image evolution at the very earliest phase of combustion immediately revealed the presence of a previously unreported feature. This novel aspect is the presence of clearly separate combustion regimes which are typically only resolvable in the very early phase after ignition, prior to detectable pressure rise due to heat release. The characteristics of the regimes observed in this early phase are found to correlate well with the subsequent gross combustion behaviour of the cycle.
Design of Multiple-Sensor Weigh-in-Motion Systems
Authors: Cebon D
Published: February 2007

Theory is derived for calculating the statistical accuracy of a weigh-in-motion (WIM) system with multiple, evenly spaced force transducers, subject to random dynamic tyre forces generated by heavy vehicles. A straightforward design procedure is developed for determining the best spacing between sensors, providing the speed of the heavy vehicle traffic is known. Simulated dynamic tyre forces of two generic heavy vehicle models are used to assess the accuracy of WIM systems for a variety of conditions and it is concluded that a good design choice is to use systems with three sensors spaced along the wheel path.
Analysis of Active and Semi-Active Vehicle Suspensions Fitted with a Pneumatic Self-Energizing Levelling Device
Authors: Hall B B , Tang J S
Published: February 2007

A pneumatic self-energizing self-levelling (SESL) device is proposed in schematic form and a theoretical analysis of it is carried out. The unit allows the design suspension working space to be maintained once steady state operating conditions have been reached.

Conventional passive, semi-active and fully active suspensions are all disadvantaged by variable vehicle payloads. An investigation is carried out to determine what advantages are to be gained by combining the SESL unit with each of these types of suspension. Computing simulations have been used to show that for large payloads it has the ability to:

(a) improve the performance of a conventional passive suspension, (b) reduce the power requirements of a fully active system and (c) maintain the performance of a semi-active system close to that of a fully active system for a wide range of payloads.

It is concluded that the SESL device has most to offer when it is used in conjunction with a semi-active system containing a variable-rate switchable damper.
Customer—Supplier Relationships in the Motor Industry: A Vehicle Manufacturer's Perspective
Authors: Galt J D A , Dale B G
Published: February 2007

This paper reports a study of the supplier development process in three major assemblers of motor vehicles who have facilities based in the United Kingdom. Among the main findings are that supplier development is considered a key organizational objective, the three organizations are approaching supplier development in different ways but there are common threads running through the three approaches (for example single sourcing, measurement of performance and the provision of assistance to suppliers) and while there are clear advantages in terms of improved performance in quality, cost and delivery, the process of supplier development is not without disadvantage in relation to the resources required, reduced flexibility and worries about assisting the competition.
Combustion in a Direct Injection Diesel Engine with Increased Clearance Volume
Authors: Ladommatos N , Balian R A
Published: February 2007

The aim of the investigation was to analyse the effects of an increased clearance volume on the performance of a high-speed direct injection (DI) diesel engine, and to seek ways of ameliorating problems with combustion. Tests were carried out on a high-speed DI engine at the standard and at a lower compression ratio, and the problems with combustion were analysed. Modifications made to the fuel injection system and engine operating conditions at the lower compression ratio resulted in substantial improvements in power output and fuel economy. This investigation is relevant to DI diesel engines operating with variable compression ratio.
An Investigation for Optimization of Belt Conveyors
Authors: Manatakis E
Published: February 2007

This paper describes the problem of optimization as applied to the design and operation of conveyors for bulk solids handling. The problem centres around the minimization of the cost function, which takes into account the interaction of the conveyor-material system parameters. A new optimization technique is discussed and using the general principles of engineering economic analysis and statistical methods the optimum solution is found. By way of example, the paper describes the optimum solution of belt conveyor and multiple conveyor systems.
Buckling of Slightly Flattened Domed Ends Reinforced Locally with Fibre-Reinforced Plastic
Authors: Galletly G D , Moreton D N , Muc A
Published: February 2007

This paper discusses external pressure tests carried out on machined steel torispherical domes, such as those used as end closures on cylinders. There were small axisymmetric regions at the poles of the shells, in which the local radius was greater than the nominal one (that is the domes had increased-radius geometric imperfections, or ‘flat’ spots, in them). The ‘flat’ areas were covered with CFRP (carbon fibre reinforced plastic) and one aim of the tests was to see if the buckling strength of the reinforced imperfect domes could equal that of a similar, unreinforced, perfect dome. Two sizes of polar flattening were investigated.

The agreement between the experimental failure pressures and the theoretical predictions of the BOSOR 5 shell buckling program was good. The tests showed that the flattened dome's buckling resistance could indeed be restored (so that it equalled that of the perfect dome) by covering the flattened area (and its environs) with CFRP. It was also shown that, by applying a somewhat thicker composite layer to the localized flat region, it was possible to achieve the same buckling resistance with glass fibre reinforced plastic (GFRP) as with CFRP. The former material is, of course, much cheaper.

Perfect and imperfect (that is with local flattened regions) steel domes were also tested under external pressure. The test results and the BOSOR 5 predictions were in good agreement for these models.
Mechanics Analysis of the Die Drawing Process for Producing Oriented Polyethylene Terephthalate (PET) Tube
Authors: Craggs G
Published: February 2007

An analysis is presented of the die drawing process used to produce transparent polyethylene terephthalate (PET) tube having a high degree of molecular orientation and consequently superior mechanical properties to tube in the isotropic state. The stress in an element of material being drawn is determined from equilibrium considerations and by using the Tresca yield criterion. Flow stress values used in the analysis allow for strain rate effects during drawing and were obtained from uniaxial stress-strain data and applied to the problem using equivalent stress-strain concepts.

Results are presented of die drawing tests carried out on a large-scale die drawing facility on PET tube at 100°C. Predicted drawing loads for an assumed value of friction coefficient of 0.2 compared well with experimental values for billet velocities greater than 7 mm/min. Draw ratios of up to 3.5 were achieved in tests when there was evidence of crystallization during the free drawing of the material downstream of the die exit.
Dewatering Performance of Vibrating Screen
Authors: Ng K L
Published: February 2007

This paper presents a method for quantifying the dewatering performance of the vibrating screen so that it can be designed to meet the dewatering requirements of capacity and moisture content. An experimental linear vibrating screen was constructed and was tested with wet coal. The experimental results showed that the rate of dewatering depends on the instantaneous moisture content of the wet coal. Analysis of the experimental results showed that the dewatering performance of the vibrating screen can be quantified by three parameters. The three parameters allow the dewatering performance of the vibrating screen to be quantified in terms of the separation of free water, removal of surface moisture from the wet coal and the vibratory excitation. The experimental results also showed that the vibrating screen with a larger amplitude of vibration has a better dewatering performance.
On-Line Multi-Gearbox Monitoring of a Wire Rod Finishing Mill
Authors: Morgan G , Watton J
Published: February 2007

A microcomputer-based on-line vibration monitoring system has been developed in the School of Engineering and has now been successfully implemented at Cardiff Rod Mill. The justification for condition monitoring is presented and details are then given on the final system chosen, appropriate operational procedures and some unforeseen operational problem detections.
Deflection Characteristics of Tubular Diaphragm Separators Used in Diaphragm Separator Pumps
Authors: Brett P N , Longmore D K
Published: February 2007

A simple method is described for computing the volumetric displacement of a tubular diaphragm on a mandrel, as used in a diaphragm separator pump, for any given pressure differential across it. The computer model involves a plane strain analysis and regards the diaphragm as a curved beam in bending, shear and tension. Comparison with experiment has shown the model to give accurate predictions of diaphragm behaviour.

The design of a diaphragm is discussed, making use of the computer model. Attention is given to the choice of wall thickness, elastic modulus and mandrel support and the manner in which they affect diaphragm life, the volumetric efficiency and operation of the pump.
Advances in Rail Wagon Design
Authors: Etwell M W J
Published: February 2007

This paper is based on a paper presented to the Intermodal Europe 88 Conference (at London in 1988). Design parameter developments are briefly outlined with emphasis on the rail gauge and the problem of transporting higher volume containers of 9 ft 0 in high x 2600 mm wide and 9 ft 6 in high x 2500 mm wide. New intermodal techniques developed for use by BR are reviewed together with new bogie developments and a concept of a self-contained rail distribution system.
New-Generation Ore Wagons on the Mount Newman Mining Railroad
Authors: Donnelly R F , Butcher C F G
Published: February 2007

Increasing railing costs and an ageing ore car fleet were the main requirements for the purchase of seven prototype ore cars. The use of a bogieless suspension reduced tare weight and stainless steel floors and side walls are expected to reduce maintenance costs. Fuel savings are realized from an increase in the tare–gross ratio and improved aerodynamics.
Railway Wheelsets
Authors: Wise S
Published: February 2007

A seminar on ‘Railway wheelsets’ was organized by the Railway Division of the Institution of Mechanical Engineers: it was held in London on 14 March 1989
A Simulation Study of Some Starting Behaviour Problems of Diesel Hydraulic Locomotives
Authors: Lu G , Sharp R S
Published: February 2007

An analytical investigation of the starting behaviour of a diesel hydraulic locomotive having coupled axle drive is carried out. A transmission system model with 13 degrees-of-freedom is developed. Calculated results show the starting behaviour of the system with coupled axle drive to be inferior to that of a system with individual axle drive, which is consistent with practical experience. The effects of the branch stiffnesses of the transmission system, the backlashes and the stiffness of the torque arm support on the starting behaviour are discussed. Further, a new equivalent transmission chain is developed to get a simple and easy access to improve the starting behaviour in practice. It is believed that this study contributes toward understanding of the starting behaviour of diesel hydraulic locomotives with coupled axle drive.
The Rolling Stock on Belgium Railways (NMBS/SNCB)
Authors: Soenen R
Published: February 2007

This paper describes the evolution of the rolling stock of the Belgian Railways over the last decade.
Development of a System for Power Output Co-Operation Between Electric Railcars and Diesel Railcars
Authors: Nagase K , Uruga K
Published: February 2007

Much difficulty has been encountered in a co-operation control multiple operation between electric cars and diesel cars, because the structure and performance of the respective control systems are very different from each other. Diesel cars are characterized by more or less constant output from the initial to middle-speed range and constant torque beyond the middle-speed range. Electric cars are characterized by virtually constant torque from the initial to middle-speed range, with the output decided by notch order beyond the middle-speed range. The authors propose a new co-operation control system based upon an entirely new concept. This system changes a general notch order into a suitable notch order for the diesel car, depending on the electric car's speed. The system was mounted on the Japan Railways Group's (JR) electric and diesel cars and tested on the main line of JR Kyushu. Based on this test result, introduction of the system in commercial service was decided upon and practical operation began on 29 April 1989.
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.
Advances in Materials Technology and Their Applications to Military Aircraft
Authors: Sharples T
Published: February 2007

Modern revolutionary advances such as the introduction of carbon fibre composites are discussed within a broad historical perspective covering the major milestones. These include the development of titanium and of aluminium-lithium alloys and the advent of finite element programs. Several specific modern examples are cited.
Cooling System Optimization in High-duty Aerospace Transmissions
Authors: Dominy J
Published: February 2007

The long-term future of large aircraft engines is seen to lie in ‘ultra high bypass ratio’ (UHB) powerplant. One possibility for such engines is to use reduction gearboxes to allow the relatively high-speed turbine and the low-speed fan to run at their optimum efficiencies. An important constraint upon the application of these gearboxes is the weight and drag of the cooling system. This paper presents an analysis of cooler requirements for a transmission with its own integral oil system. Results are presented for a 4.5 MW gearbox typical of the more powerful turbo prop engines currently in civil service. The importance of transmission efficiency and scavenge temperature in defining the necessary size (thus weight) of the cooler is demonstrated. It is shown that active control of the cooler duct results is further efficiency improvements.
Auxiliary Power
Authors: Warne E H
Published: February 2007

Requirements for civil and military applications are reviewed and power sources discussed. Features of the gas turbine auxiliary power unit are presented, including performance data, current units and operational considerations. The paper concludes by considering future design moves.
Validating and Updating Finite Element Models Using Experimental Measurements of Dynamics
Authors: McCulloch C F , Vanhonacker P , Dascotte E
Published: February 2007

A method is proposed for updating finite element models of structural dynamics using the results of experimental modal analysis, based on the sensitivities to changes in physical parameters. The method avoids many of the problems of incompatibility and inconsistency between the experimental and analytical modal data sets and enables the user to express confidence in measured data and modelling assumptions, allowing flexible but automated model updating.
Ground Support Equipment Maintenance Data Analysis
Authors: Sowden R E
Published: February 2007

Microcomputers and specially developed programs have now been installed at over twenty Royal Air Force front-line units to improve the management of ground support equipment. At these, most of the traditional engineering management aids have now been replaced by the computer, but the analysis of the maintenance data is extremely limited and still performed manually on selected types of equipment. Accordingly, the establishment of a dedicated Ground Support Equipment Maintenance Analysis Centre has been proposed. This paper outlines how the information from the station computers should be processed to provide comprehensive, fleet-based, equipment performance assessments. Furthermore, the potential, together with the possible cost benefits of the proposed system, is considered.
Twenty-First Century Aero-Engine Design: The Environmental Factor
Authors: Jamieson J B
Published: February 2007

This paper briefly examines some of the issues facing manufacturers and operators of aero-engines in responding to thrust needs of the twenty-first century and discusses some of the fundamental issues aimed at quieter and cleaner engines.
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.
The Origins and Evolution of Design Requirements for British Military Aircraft
Authors: Meekcoms K J
Published: February 2007

This paper traces the origins and evolution of design requirements for British military aircraft over a period of 80 years, recording significant developments, changes and some personalities during that time. The publication of this paper also marks the fiftieth anniversary of the UK military Joint Airworthiness Committee.
The Role of the Quadriceps in Controlling Impulsive Forces around Heel Strike
Authors: Jefferson R J , Collins J J , Whittle M W , Radin E L , O'Connor J J
Published: February 2007

The damaging effect of transient loads on joints has been observed in vitro and in vivo, and may be an aetiological factor in osteoarthrosis. The events around heel strike, when the velocity of the foot is brought rapidly to zero, may be a source of such loads in normal activity. By modifying the rate at which the limb descends to the ground, quadriceps action influences the magnitude of the heel strike transient. Experiments were carried out to analyse the occurrence of these transients, and a two-dimensional mathematical model of the knee joint and lower leg was used to calculate the forces developed at the knee in response to them. Paralysis of the quadriceps resulted in a large increase in the heel strike transient.
Effects of Structural Variation on Young's Modulus of Non-Human Cancellous Bone
Authors: Hodgskinson R , Currey J D
Published: February 2007

The modulus of elasticity of cubes of cancellous bone, tested in three orthogonal directions, was measured along with apparent density, fabric (measured using image analysis techniques), connectivity and mineral volume fraction. Multiple regression was used to relate Young's modulus and the explanatory variables. The most important explanatory variable was apparent density; fabric was also important. Connectivity was highly correlated with apparent density, and so it is difficult to assign relative weights to these two variables. However, both have a significant, and separate, effect on Young's modulus. The total variance in Young's modulus explained by these three variables was about 85 per cent. This implies that other explanatory variables are either unimportant or highly correlated with the variables listed above. Mineral volume fraction is shown to be an unimportant variable, and arguments are produced why this is to be expected, even though it is highly important in explaining the variation in Young's modulus of compact bone.
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.
The Effect of Variation in Structure on the Young's Modulus of Cancellous Bone: A Comparison of Human and Non-Human Material
Authors: Hodgskinson R , Currey J D
Published: February 2007

The Young's modulus of cubes of human cancellous bone was measured in three orthogonal directions. Apparent density and mineral volume fraction were also measured, as were two architectural variables, fabric and connectivity, which were determined using image analysis techniques. Multiple regression was used to relate the Young's modulus to the four explanatory variables. The results from this study are compared with those obtained from a previous investigation using non-human cancellous bone. The relationships revealed by the two studies are very similar. It was possible to explain approximately 93 per cent of the variance in Young's modulus using the four variables in this present study. Apparent density is the major explanatory variable in both studies and shows a strong correlation with connectivity. In common with the non-human study the measure of fabric is a worthwhile explanatory variable; however, connectivity and mineral volume fraction are relatively unimportant. The four explanatory variables contribute to a successful model for the prediction of Young's modulus. Any other candidate variables are likely to be unimportant or be highly correlated with those already investigated.
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.
Socket Size and the Expected Quality of its Fixation in the Cemented Total Hip Arthroplasty
Authors: Wroblewski B M
Published: February 2007

This note describes a mathematical study which points out the possible correlation between the socket size and quality of its fixation in cemented total hip arthroplasty.
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.
The Potential of Hydrogels as Synthetic Articular Cartilage
Authors: Corkhill P H , Trevett A S , Tighe B J
Published: February 2007

The relatively poor mechanical properties of conventional synthetic hydrogels are illustrated and compared with those of articular cartilage. By using the composite structure of the natural material as a model a new family of hydrogels, based on interpenetrating polymer network (IPN) technology, has been developed. The underlying synthetic strategies are discussed and the properties of a novel representative network presented. IPN formation produces networks that are stiffer and stronger than the hydrogel copolymers of similar water content. In this behaviour these simple IPNs begin to mimic the properties of biological hydrogel composites. Thus, these materials have exciting potential for demanding in vivo applications.
Maximum Finger Force Prediction Using a Planar Simulation of the Middle Finger
Authors: Lee J W , Rim K
Published: February 2007

Maximum isometric finger-grip forces were predicted using a biomechanical model for plane motion of the middle finger. In the course of this study, mathematical representations of tendon displacement, the moment arm of tendon at the finger joints and muscle force-length relationship were investigated. The information gathered was applied to the model to estimate the maximum grip force of the middle finger gripping cylinders of different sizes. Muscle force per unit physiological cross-section area of 30 N/cm2 resulted in good agreement with measured force. However, for finger postures having an acute proximal interphalangeal joint angle, the estimated force was greater than that measured. Various joint angles were applied to the model to simulate the wrist and finger postures not limited to the cylinder grip. In general, the finger force was greatest with the wrist in its extended position and at acute flexion of the proximal interphalangeal joint. The maximum finger force occurred at reduced metacarpophalangeal joint angles as the wrist joint changed from an extended position to a flexed one. It is also postulated that muscle force-length relationship is an important factor in muscle force predictions. The data obtained by this research are useful for the design of handles and the current model is applicable to the analysis of hand postures for workers using hand tools.
A Review of the Numerical Analysis of Blood Flow in Arterial Bifurcations
Authors: Xu X Y , Collins M W
Published: February 2007

Arterial bifurcation flow has been of special interest for some years because of its important role in the formation of atherosclerotic plaques and thrombi. To investigate the flow phenomena analytically, four major factors need to be accommodated—the three-dimensionality of a general bifurcation, the pulsatile nature of the laminar flow, the distensibility of the arterial wall and the non- Newtonian character of the blood. In this review, both engineering and medical aspects of each factor are carefully surveyed. It is demonstrated that the latest generation of computational fluid dynamics codes can treat this problem area and that it is both feasible and desirable to investigate the effects of each independent factor.
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.
Computational Fluid Dynamics without Complex Mathematics: The Advantages for Thermofluids Education
Authors: Aston J G L
Published: February 2007

With the vastly increased capabilities of computers within the past decade the teaching of thermodynamics and fluid dynamics must evolve to encompass more treatment of numerical methods than before. Accepting that CFD will occupy a significant portion of undergraduate and postgraduate syllabuses in the 1990s, this paper looks at certain conceptual difficulties associated with conventional approaches in CFD and the impact of these on thermofluids education. An alternative approach to CFD which avoids complicated mathematics is described. It is argued that such an approach can promote a better understanding of fluid behavioural mechanisms and, thereby, should be of benefit to both research and teaching in thermofluids.
The Calculation of Thermodynamic Properties of Steam for Minimum Computer Access Time
Authors: Muneer T , Scott S M
Published: February 2007

Energy engineers involved in the design of thermal plant often need to compute properties of gases and vapours over a large part of the thermodynamic surface. For such applications an equation-based approach is efficient and accurate. In this paper simple formulations for the thermodynamic properties of steam are provided which enable computations to be made with a significant reduction in computer access time, the comparison being made against the DAMPF reference package.
OXTOPS: A Computer Program for Teaching Thermodynamic Cycles
Authors: Hands B A , Ross T P
Published: February 2007

A computer program has been written to help undergraduates learn the rudiments of thermodynamic processes and cycles by using computer-generated data rather than by the more laborious method using tables. The process or cycle can be defined by the student, and can be displayed to scale on a selection of thermodynamic property diagrams. Although the program is intended primarily for teaching, it may also be used for simple design optimization.
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.
Output and Efficiency of the Closed-Cycle Gas Turbine
Authors: Woods W A , Bevan P J , Bevan D I
Published: February 2007

The paper considers the closed-cycle gas turbine plant from the educational aspect of knowledge and understanding. The special qualitative features of the T-s diagram are discussed and a quantitative treatment of a simple model presented. A new expression for the maximum efficiency is given and interesting aspects of the results discussed. Technical and educational conclusions are drawn from the work.
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.
Experimental Investigation of Flow and Force Characteristics of Hydraulic Poppet and Disc Valves
Authors: Johnston D N , Edge K A , Vaughan N D
Published: February 2007

Tests have been performed on a range of different poppet and disc valves operating under steady flow, non-cavitating conditions, for Reynolds numbers greater than 2500. The working fluid was water, and the axisymmetric valve housing was constructed from clear perspex to facilitate flow visualization. Measured flow coefficients and force characteristics show marked differences depending on valve geometry and opening. These differences are explained with reference to visualized flow patterns.
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.
Modelling the Temperature Dependence of Thermophysical Properties in a Closed Method for Regenerative Heat-Exchanger Simulations
Authors: Hill A , Willmott A J
Published: February 2007

A new technique for the computer simulation of thermal regenerators is presented. The method is both closed and allows for the spatial representation of the temperature dependence of the thermophysical properties of fluid and solid which strongly influence the realistic modelling of high-temperature regenerators. It is shown that the method is computationally more efficient than a comparable open scheme.
The Use of Feed Heating in the Steam Cycle of a Combined Cycle Power Plant
Authors: Horlock J H
Published: February 2007

A simplified analysis is given for determination of the overall efficiency of a recuperative combined gas turbine/steam power plant, with and without feed heating. It is shown that for prescribed state properties in the (higher) gas turbine plant and specified pressures in the (lower) steam cycle, feed heating leads to reduced plant overall efficiency. However, if the temperature of the gas leaving the heat-recovery steam generator is limited (to avoid corrosion in the heat-recovery steam generator) then the disadvantage resulting from the introduction of feed heating is small.
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.