bluuebunny/crossref_metadata_2025 huggingface dataset:
Computation of the Aerothermodynamic Field of Laminar Diffusion Flames
Authors: Abam D P S
Published: February 2007

This paper describes a theoretical and experimental investigation of laminar diffusion flames leading to their structural characterization. A theoretical model is developed from experimental correlations of major species concentrations and temperature against suitably defined conserved species, otherwise called mixture fraction, using the Shvab Zeldovich similarity principle. These correlations yield a set of similarity equations of stoichiometry which express implicit functional dependence of species concentrations and temperature on mixture fraction. The momentum conservation equation is then solved simultaneously with the conserved species equation to establish the aerothermodynamic field of the flame. In the form defined, the mixture fraction is measured, having well-defined initial and boundary conditions, and allows examination and identification of regions of the flame characterizing either diffusive flow or combined diffusive and chemically reactive flow. Furthermore, it is found experimentally that at a fixed value of mixture fraction Z = 0.059, corresponding to a methane/air equivalence ratio of 1.08, the local temperature maxima occur in the neighbourhood of the visible luminous flame boundary. This observation is used to check the accuracy of calculations of the physical dimensions of the flame. Good comparison is obtained between computed and measured values and distribution of the major species concentrations, temperature and velocities. The model allows investigation of the chemical kinetic structure through its effectiveness in the computation of reaction rates.
Energy Loss in Gear Tooth Impact
Authors: Smith J D
Published: February 2007

Experiments to determine the loss of energy when gear teeth impact are described. The results show much greater loss of torsional energy than expected and an explanation is put forward. The test results are relevant for highly non-linear gearbox vibration problems but cannot be used directly when the teeth remain in contact.
An Experimental and Theoretical Study of Lubricant Film Extent and Flowrate in Grooved Rectangular Pad Slider Thrust Bearings
Authors: Hargreaves D J , Taylor C M
Published: February 2007

In liquid lubricated journal bearings an accurate assessment of the flowrate requires detailed consideration of the extent of the cavitated or ruptured region. Particular difficulties are encountered analytically when attempting to locate the boundary where the lubricant film reforms, normally in the vicinity of a supply groove. Most bearing analyses omit a consideration of this reformation boundary because of such difficulties. However, it is now widely recognized that the prediction of flowrate may be seriously in error if reformation effects are not incorporated in the analysis. In the present paper an externally pressurized, grooved, rectangular pad, slider hearing is examined. An air-lubricant interface may form in such a bearing which is akin to the reformation boundary encountered in journal bearings. A numerical analysis scheme to locate the interface is described in detail and theoretical predictions of bearing flowrate and interface position presented for a wide range of conditions. A comparison of the analytical predictions with experimental measurements is undertaken.
Design of a Radial Electromagnetic Bearing for the Vibration Control of a Supercritical Shaft
Authors: Gondhalekar V , Holmes R
Published: February 2007

Recently magnetic bearings have been proposed by several researchers and shown to be viable on a variety of rotor assemblies. This paper describes the design of such a bearing and elucidates features hitherto not employed by other workers. These include an original approach to the design of the electromagnets and their amplifiers, and to software in a digital control system, to condition the control signals so as to make the magnets appear to be linear and uncoupled. The resulting system has features which make it suitable for the control of rotor bearing assemblies.
Axisymmetric Elastic-Plastic Buckling of Axial and Pressure Loaded Cylinders
Authors: Croll J G A
Published: February 2007

An analytical approach to the axisymmetric elastic buckling of isotropic cylinders, under arbitrary combinations of radial pressure and axial loading, is used as the basis of a first surface yield and a first full plasticity criterion of plastic collapse. Bending disturbances caused by the boundary constraint of both Poisson bulging under axial loading and the effects of arbitrary radial pressure loading are combined with any prescribed initial geometric errors to provide total ‘equivalent imperfection parameters’ on an otherwise perfectly cylindrical prebuckling state. Elasto-plastic collapse loads are then summarized in terms of just three parameters: the total equivalent membrane and bending imperfections parameters and the ratio of the minimum elastic classical critical axial stress to the material yield stress.

The ease with which shells of arbitrary end conditions or internal ring stiffener supports can be treated, the consideration that the results so closely reproduce and extend the more elaborate numerical solutions, and the possible simplifications of the method, make it an ideal basis for design against axisymmetric collapse.
System Prediction Using Damped Component Modes
Authors: Martin K F , Ghlaim K H
Published: February 2007

This paper describes a method of predicting the vibrational characteristics of a system when the components, which have mass, stiffness and damping, are connected together by connections which are characterized by stiffness and damping. A matrix set involving the complex eigenvalues and eigenvectors of the components together with a connection matrix is solved to give system eigenvalues and eigenvectors. The application of this method to a particular system is shown to produce the same results as those obtained for the unsubstructured system.
25 Kv Electrical Multiple Unit for The Kowloon–Canton Railway (British Section)
Authors: Botham G J M , McNeil J H
Published: February 2007

The paper gives a brief history of the Kowloon–Canton Railway and outlines its modernization. The new rolling stock is described together with some service experiences. Some reliability data are given with a discussion of the need for a worldwide industry reliability standard.
The Theoretical and Photoelastic Investigation of Stresses in Chassis Frame Joints
Authors: Tidbury G H , Alvi M S
Published: February 2007

The high stresses in the joints of chassis frames subject to torsion are estimated theoretically and confirmed by tests on photoelastic models. The joints considered are between channel section cross members welded or continuously attached to the webs of channel section side members. The detailed stress distribution in the side members has been estimated using classical plate theory to find the forces resisting the warping displacements of the cross members. Models of joints and a complete frame were made from channel section castings of birefringement material and coated with reflective material to allow the use of a reflection polariscope to analyse the stress distribution. The theoretical results were compared with the results from approximate theories as well as with the photoelastic test results.
The Motor Car in the Year 2000
Authors: Lucas G G
Published: February 2007

This paper presents a forecast of the expected shape, drag, power unit, transmission, weight etc. of the motor car in the year 2000 and beyond. Some consideration is given to whether a car in any form will be in existence at that date.
Aerodynamic Influences on the Performance of the Grand Prix Racing Car
Authors: BSc J A Dominy , Dominy R G
Published: February 2007

The remarkable cornering power of the modern Formula 1 Grand Prix car is almost entirely due to its aerodynamic characteristics. As aerodynamic research generates much more data than can be track tested, it has been found necessary to develop an analytical model to investigate the effect of downforce, drag and centre of pressure on lap times round a sample circuit thus sifting the experimental results.

This paper presents such an analysis and applies it to an investigation of the performance of a Formula 1 car round a typical circuit.
Likely Advances in Mechanics, Cooling, Vibration and Noise of Automotive Engines
Authors: Pride T , Anderton D
Published: February 2007

This paper outlines various aspects of automotive engine designs to achieve lightweight low noise automotive engines with improved efficiency low mechanical losses and reduced heat losses to coolant.
Control of Warship Machinery
Authors: Neumann J
Published: February 2007

The paper traces the evolution of remote and automatic control of warships' machinery. It refers to various incidents and developments which have stimulated the application of centralized control rooms outside the machinery spaces and the evolution of new concepts of presentation of data to the operators.

Experience is drawn from the Royal Navy when looking at the historical development of control systems and account is also taken of designs for several other Western navies.

The influence of the rapid advances in control technology is reviewed drawing upon experience of pneumatic systems. analogue electronic designs, and the present concepts for distributed digital installations. The paper also takes a speculative look at future designs particularly with respect to presentation of information to the operator. Lessons learnt along the way are highlighted in relation to manning levels and training requirements which must be borne in mind by the control system designer (and/or specifier) prior to the introduction of new system technologies into the fleet.
Passenger Comfort—the Role of Active Suspensions
Authors: Pollard M G , Simons N J A
Published: February 2007

The paper examines the existing and proposed methods of assessing passenger comfort and makes proposals as to acceptable levels of vibrations for railway vehicles. The limitations of passive suspensions are outlined and the advantages of active suspensions in improving passenger comfort cost-effectively are described. Finally some results of active suspension development are presented.
Measurement of the Aerodynamic and Rolling Resistances of Road Tanker Vehicles from Coast-Down Tests
Authors: Evans E M , Zemroch P J
Published: February 2007

The aerodynamic and rolling resistances of three articulated road tankers have been measured in a statistically planned series of coast-down tests. Pairs of deceleration and velocity measurements were obtained by applying digital filters to the recorded times at which the vehicle crossed special reflective strips anchored to the road surface. A statistical error analysis showed that the resistances to motion then could be validly estimated by fitting a two-parameter regression model to these measurements.

The aerodynamic drag coefficient, CD, was found to be similar for all three vehicles and CD, did not depend on their loading conditions. The rolling resistance, R, approximately doubled when the vehicle was loaded to three times its unladen weight. Significant reductions in R were obtained by changing from twin tyres to single wide tyres on the trailer.
A Study of the Braking Performance of Motor-Cyclists With an Integrated Braking System
Authors: Mortimer R G
Published: February 2007

The purpose of the study was to evaluate the braking performance of motorcyclists using an integrated front and rear brake by comparison with conventional separated front and rear brakes. Stopping distances and the occurrence of wheel locking were measured in braking runs on a straight, flat asphalt surface, in dry and wet conditions, using the front brake only, the rear or integrated brake and both the front and rear or integrated brakes. Speed prior to braking was 40.3 km/h.

It was found that mean decelerations using front brakes alone were the same for all motorcycles on the dry and wet surfaces, and significantly greater than rear brakes alone for the dry road. The integrated (foot) brake provided significantly greater mean deceleration performance than rear (foot) brakes on both surfaces. The use of both brakes provided significantly greater mean decelerations than rear brakes alone, on the dry and wet surfaces, but not the integrated brake; and use of both brakes on the motorcycle with integrated brakes produced significantly greater mean decelerations than front brakes alone on all the motorcycles on the wet surface. There were no statistically significant effects of test conditions on the mean frequency of wheel locking, but they were least frequent with the integrated brake.

It was concluded that inexperienced and experienced riders could obtain substantial improvements in braking with an integrated braking system which should reduce their involvement in collisions. Further studies should be made on surfaces of lower coefficient of friction, gravel and on curves.
Braking of Articulated Vehicles and the Advantages of Anti-Wheel Lock Devices
Authors: Birtwisle R J
Published: February 2007

As a result of a series of tests on various tractor/trailer combinations operating within the Esso Petroleum fleet. anti-lock braking equipment was specified as standard on semi-trailer running gears in preference to load sensing valves. The adoption of this equipment increased the performance of the vehicle combination in the unladen condition and corrected an imbalance in the rate of brake lining wear.
The Development of Advanced High Speed Vehicles in Sweden
Authors: Andersson E , Nilstam N
Published: February 2007

The rail network of Sweden is characterized by frequent curves, which limit the speed of conventional rolling stock to moderate levels. Speed of travel is, however, probably the most important factor in competition between different modes of transport, both now and in the future. For economic reasons the existing track must be used, with minimum modifications. Effort in Sweden has therefore been concentrated on the development of a new technology, making it possible to run at 35–60 per cent higher speeds on existing track. At these higher speeds comfort levels and track forces must not be worse than for current rolling stock running at present speeds on the Swedish main line track. In order to satisfy these requirements, future vehicles must be equipped with car body tilting, and must also exhibit food dynamic interaction with irregular track.

Swedish State Railways (SJ) and ASEA have jointly developed and tested a new concept, including hydraulic or pneumatic car body tilting and radial steering bogies. These bogies allow for high speed through curves without excessive lateral forces and the associated wear on wheels and rails. In this bogie it has been possible to optimize primary suspension and damping parameters so as to maintain stability without hunting at speeds of up to at least 200 km/h.

An experimental train set, type X15, was the subject of extensive tests during the period 1975–82. The design of the bogies and car body tilting systems has been supported by computer simulation programs. New methods of analysis have been developed and validated as an integral part of the development project. The simulation technique has proved to be very useful and accurate in the prediction of vehicle dynamic behaviour. Also some tests of passengers' opinions on comfort in tilting trains have been carried out.
Theoretical Prediction and Experimental Substantiation of the Ground Pressure Distribution and Tractive Performance of Tracked Vehicles
Authors: Wong J Y , Garber M , Preston-Thomas J
Published: February 2007

An analytical framework for predicting the ground pressure distribution and tractive performance of tracked vehicles is presented. It takes into account all major design parameters of the vehicle as well as the pressure—sinkage and shearing characteristics and the response to repetitive loading of the terrain. The subsequent substantiation of the analytical method by means of full-scale tests made with an instrumented vehicle is described. A comparison between the theoretical prediction and test results is made and it is found that there is a fairly close agreement between them. This paper includes three sections: (i) an analytical method for predicting the normal pressure distribution; (ii) an analytical method for predicting the shear stress distribution and tractive performance; (iii) experimental substantiation of the analytical framework by means of full-scale tests. The analytical framework presented is suitable for evaluating the effects of vehicle design parameters and terrain conditions on the performance of tracked vehicles with relatively short track pitch designed for high speed operation and for comparing the tractive performance of different tracked vehicle designs.
Combined Thermal and Mechanical Analysis of Drum Brakes
Authors: Day A J , Harding P R J , Newcomb T P
Published: February 2007

The frictional heat generated during braking is included in the full analysis of a commercial vehicle drum brake, avoiding artificial heat partitioning by the use of a novel technique for the dynamic simulation of heat transfer at the friction interface. The effects of lining wear, empirically related to local values of surface temperature and pressure, together with thermo-elastic effects, are taken account of in the calculation of interface pressure distributions and consequent brake performance. Analyses have been completed using two-dimensional finite element meshes which model the combined assembly of brake shoes, linings and drum. These have been validated by comparisons between measured and calculated brake performance, and by observations of rubbing contact pattern.
The Ford 3 × 6 Engine Programme
Authors: Stojek D , Bottomley D
Published: February 2007

The Ford 3 × 6 engine has been developed as an advanced study to achieve maximum possible fuel economy whilst maintaining the performance of the production 2.8 litre injection engine. The standard 2.8 litre injection engine provides the base for the dual displacement concept. Separation into two engines is accomplished by a completely divided intake manifold and dual plate throttle body. This permits the right bank of cylinders (engine 1) to operate at all times and the left bank (engine 2) to operate separately, only when needed. Typically, six-cylinder operation is selected for cold engine operation and at throttle angles greater than 37°. The sequential opening of the two throttle plates for engine 1 and engine 2 is controlled by a mechanical control system. Electronic fuel injection is controlled by the Ford EEC IV electronic engine control computer. The EEC IV also controls separate engine spark advance, deceleration fuel cut-off, cold engine enrichment, idle speed, and provides fuel consumption input to the vehicle's trip computer. Development tests to date have shown approximately 20 per cent improvement in ECE cycle fuel consumption.
Closing the Loop
Authors: Rizk W
Published: February 2007

A concept or invention which goes through the various phases of design, manufacture, sale to and use by a customer should not end there. ‘Closing the loop’ means feedback at every stage and is a vital ingredient for the success and continued improvement of a product or system, be it large or small. The need for ‘closing the loop’ does not only apply to hardware but applies equally to the education and training of engineers. Equally important also is the need to inject into an engineering operation or an educational system the experience gained by a senior engineer in the course of his career. The President deals with some interesting examples of closing or failing to close the loop in a number of varied subjects from the simple to the complex.
An Analytical Approach to the Estimation of the Performance of Steam Turbine Cycles Off-Design
Authors: Weir C D
Published: February 2007

In estimating the performance of a real steam turbine cycle off-design it is essential to ensure that the flows as determined by heat balance conditions are compatible with the flow-passing capabilities of the stage groups of the machine. Once this condition of compatibility is satisfied the stage group inlet and outlet pressures are uniquely established and these, in conjunction with the (assumed known) locus of the off-design stateline, allow the off-design performance in terms of output and heat rate to be determined.

In the case of a condensing-only cycle operating under straightforward part load condition it is a relatively simple matter to arrive at the stage group pressures consistent with both the heat balance and the flow-passing characteristics. Under certain more extreme off-design conditions, and also in the case of passout machines where the work output and the passout quality may vary independently over a rather wide range, the problem of ensuring compatibility is, however, less easily solved. This is an aspect of steam turbine cycle design which does not appear to have been systematically discussed in the open literature.

The method presented in this paper is based on an analytical approach which permits solution by a rapidly convergent iterative technique. The stage group pressures arrived at in this fashion, and hence the estimate of thermal performance based upon them, correspond to a degree of accuracy quite sufficient for all purposes to those of the equivalent real cycles.
Pressure—Temperature Relationships in Buried Pipelines
Authors: Awoseyin R S
Published: February 2007

It is often required that buried pipelines be hydrostatically tested before commissioning. This is particularly necessary where the pipeline is intended for gas transport. The author was in the team of designers for a 250 km ethylene pipeline in the UK and had the assignment of predicting the effect on the line pressure of a given temperature variation.
Marine Technology—Present and Future
Authors: Thompson R V
Published: February 2007

The paper attempts to present a scenario of the change in energy sources and availability occurring in the world today and its effect on trading patterns. As a result of this analysis, an impression of shipping reguirements and hence potential demand is developed. Associated required engineering developments are postulated both in the area of traditional sea-going trade and also offshore and subsea systems.

The progress of specific related research projects and their expected contributions to technological expertise and operational availability is presented.

The precarious position of the UK industry versus the rest of the world is highlighted, and a plea made for a technological lead recovery.
UKAEA and CEGB Development Programmes
Authors: Birss I R , Gregory A R
Published: February 2007

The best method of identifying and solving the problems that might arise while decommissioning a nuclear reactor is to pursue a real project. The Windscale advanced gas-cooled reactor (WAGR) project has already highlighted several topics and thus indicated the direction in which the development programme should go. It is recognized that the concrete pressure vessels, which are not part of the WAGR structure, present special problems and so most of the CEGB work to date has been aimed in that direction. Both programmes are described.
Decommissioning Windscale Advanced Gas-Cooled Reactor
Authors: Lawton H
Published: February 2007

This paper describes the UKAEA project to decommission the Windscale advanced gas-cooled reactor. The plan is to take down the reactor itself, the heat exchangers and the sphere in which they are all contained. A special remote-handling machine is being developed which will cut up the radioactive items, and a facility is being built to package the waste for storage and disposal.
The First Twenty Years of Oil and Gas Development Offshore UK—An Engineer Reflects
Authors: Patten Tom
Published: February 2007

Following a summary of the chronological development from 1965 to 1984 of UK offshore gas and oil production, the paper offers a subjective selection of engineering features which have been significant. The author then sets out his thoughts on the present challenges and points to some possible future changes in offshore engineering.
Operation of Diesel Engines on Residual Fuel Oil
Authors: Ford J A H , Lowe W
Published: February 2007

The use of residual fuel oil for diesel generation is now well established for base load operation. The North of Scotland Hydro-Electric Board (NSHEB) has some twenty years of operational experience in supplying electricity in the Scottish Islands employing twenty-three K Major diesel engines in four power stations at Kirkwall, Lerwick, Loch Carnan and Stornoway. The paper describes the continuous development work undertaken by the engine manufacturers, Mirrlees Blackstone and the NSHEB, in increasing engine output and efficiency over the period, together with improvements in reliability and durability showing trends in modern engine design leading to the current Mark 3 version of the engine.
Linear Dynamics of Free-Piston Stirling Engines
Authors: Redlich R W , Berchowitz D M
Published: February 2007

The free-piston Stirling engine (FPSE) is a heat driven mechanical oscillator from which power can be extracted. Linear dynamics is applied here in order to obtain: a stability criterion, a means for determining the oscillation frequency, relative amplitudes of the dynamic components, effects of friction on starting and the locus of the roots of the system determinant. Three common configurations of these engines are investigated.
Explosion Hazards in Offshore Motion Compensators
Authors: Main B G
Published: February 2007

Auto-ignition data for phosphate ester hydraulic fluids and explosion initiators in high pressure hydraulic/pneumatic motion compensators are reviewed. Data obtained in this study highlight the potential increased danger due to contamination of fire-resistant fluids.
Diesel Engine Design Aspects for Heavy Fuel Operation
Authors: Rosgren C-E
Published: February 2007

Describes the state-of-the-art in medium-speed diesel engine development, with the emphasis on heavy fuel operation. Outlines the requirements for efficient combustion as well as achievements in structural safety of critical components.
Diesel Engine Research at High B.M.E.P.
Authors: Osborne A G
Published: February 2007

Demands for more power from the turbocharged diesel, without increase in bulk or weight, has led to an increase in levels of mean effective pressure by the application of high-pressure turbocharging. An investigation was conducted to determine engine performance under high b.m.e.p. conditions and this paper presents results of the experimental part of the research programme.

Test work was carried out on a single-cylinder research engine equipped with an independent pressure-charging facility. Boost pressure ratios up to 6.2:1 were used with the geometric compression ratio reduced, in stages, to 8:1, to limit peak cylinder pressure. Power levels up to 35.4 bar b.m.e.p. were produced.
‘1984’ … Better or Worse?
Authors: Shaw F
Published: February 2007

The text comprising the first part of this paper relates to the 1974 Automobile Division Chairman's Address, being random notes about the changes which have taken place since then, for better or for worse. It also points the direction in which improvements might be made, and highlights some of the errors still being made and the dangers which still exist. The second part of the paper shows, in diagram form, proposals for education and training in a career plan with recommendations for career development. The views expressed in Part 1 and the recommendations made in Part 2 are the author's own and do not necessarily reflect the policy of the Institution of Mechanical Engineers for education and training.
The Use of a Conceptual Model to Evaluate Financially Flexible Manufacturing System Projects
Authors: Primrose P L , Leonard R
Published: February 2007

It is shown that conventional financial methodologies embody assumptions which are invalid when applied to major projects such as FMS. After critically discussing the assumptions normally made during financial evaluations, the technical problems associated with designing a computer program for FMS evaluation are described and it is shown that by devising a suitable conceptual model, these limitations can be overcome. The paper concludes by demonstrating how, by use of the model developed, together with the correct data input format for the interactive program, the problems normally considered inherent with conventional financial evaluation techniques can be readily overcome.
Evaluating the ‘Intangible’ Benefits of Flexible Manufacturing Systems by Use of Discounted Cash Flow Algorithms within a Comprehensive Computer Program
Authors: Primrose P L , Leonard R
Published: February 2007

The range of benefits of flexible manufacturing systems (FMS), previously quoted as ‘intangibles’, is critically discussed and it is shown that contrary to established opinion the factors comprising the ‘intangibles’ can, in fact, be quantified. The paper then goes on to consider the principles involved when financially evaluating a proposed system and it is demonstrated that by incorporating accepted accounting procedures within a comprehensive computer program, professional engineers can readily carry out a detailed evaluation which will prove acceptable to company accountants. Subsequently, the paper then shows that although considerable data are needed to quantify precisely the benefits of FMS, most of this information already exists ‘in-house’, while the rest can be generated from technical design simulations, performed after the financial evaluation programs have identified areas for optimum FMS investment within a company. The net result of these procedures is that FMS evaluations can be more accurately performed than studies relating to other major capital projects normally encountered in engineering.
Drawing up the Purchasing Specification
Authors: Macdonald R M
Published: February 2007

The purchasing specification is an essential part of the tender/contract documents. This paper describes the main stages in the preparation of a purchasing specification, and a typical format is explained in detail. The major sections, descriptive headings and supporting clauses are set out together with notes on drafting and pitfalls to avoid.
The Development of an Automatic Procedure for the Digital Simulation of Hydraulic Systems
Authors: Hull S R , Bowns D E
Published: February 2007

This paper describes a computer software package developed at the University of Bath to aid the designer of hydraulic systems. The package is capable of simulating the dynamic and steady state behaviour of hydraulic circuits and its use does not require the designer to gain a high degree of computational skill. The paper continues by discussing methods employed both to minimize the size of the simulation program and to ensure that the program runs as quickly as possible. A case study is described and the paper concludes by taking a general view of the role of simulation in the design of hydraulic systems.
A Theoretical Model for the Dynamic Resistance in Resistance Spot Welds
Authors: Cho H S , Cho Y J
Published: February 2007

Although the behaviour of dynamic resistance has been reported to give a good indication of weld quality for the process of resistance spot welding, this resistance variable has not been widely used for the purpose of a feedback controller design as well as for the determination of a good welding condition required for a specified weld material. This is mainly due to the fact that no analytical method is at present available to describe the behaviour of the variable. This paper presents an analytical model that can predict the variation of the resistance. In this model the complicated phenomenon of the thermo-electric interaction at the interface is included to obtain both the voltage and temperature distributions in the weldment. The computed dynamic resistance based upon this model is compared with that experimentally obtained for the case of welding of mild steel. The comparison of results shows that this numerical analysis enables the behaviour of the dynamic resistance to be predicted fairly accurately.
Applications of Linear Programming to Engineering Metrology
Authors: Chetwynd D G
Published: February 2007

Computer-based metrology now makes use of exchange algorithms for computing best-fit geometries in which the solution is obtained by a series of iterations each involving the exchange of one previously unused data point for one of the dominant points of the previous iteration according to formal rules. While conferring large advantages in specific circumstances, their major significance is that of being examples of a class of optimization of much wider applicability.

This paper examines the theoretical basis of these algorithms in linear programming and develops a general approach to the solution of this class from which new applications can be derived. To maintain an engineering context in the analysis, practical examples are used, mainly from the field of roundness measurement.
Alternatives in the Design of Flexible Manufacturing Systems for Prismatic Parts
Authors: Hannam R G
Published: February 2007

This paper reviews and analyses the design and selection of the hardware of flexible manufacturing systems (FMS). The paper concentrates on systems for machining prismatic parts because this is the main application area of FMS. As the manning of systems influences hardware choices, a discussion on the influence of the manning of systems is included in the review. The paper is based on an investigation of American experiences of designing and operating systems. It is believed these experiences are very relevant to those in other countries who are planning or implementing systems.
Complexities Inherent in the Launching of a Capital Intensive Multi-Disciplined Project
Authors: Baker J W
Published: February 2007

The paper takes the reader through all stages of implementation of a large project from inception to ‘on stream’, and identifies the principal objectives of project control.
Computer Aided Engineering in Design
Authors: Richardson F J
Published: February 2007

Success of the design process hinges on efficient communication between the various functions involved. Traditionally this communication has been ‘paper based’ with information passing between sales, design, production and manufacture to describe the complete history of the product. This complex interaction between the functions depends on the availability at each stage of the most up-to-date and accurate information. The paper based system has many shortcomings in this respect particularly the inability of the designer to assess interactively the effect of any changes he may make on the cost, delivery, quality and performance of the product. The use of computer aided design as a central part of the computer aided engineering system allows a company greatly to improve communications during a project by giving the engineer a way of providing accurate information more quickly to each adjacent function while receiving feedback on the effectiveness and suitability of the product in a fraction of the time.
Quality Management
Authors: Morrison S J
Published: February 2007

The importance of quality and reliability as key determinants of competitiveness is emphasized and comparisons are made with the Japanese as competitors in international trade. The interdisciplinary nature of quality assurance is discussed and the need for bridges to be built between science, engineering, and management is identified.

A quality management model is presented in the conventional planning/organizing/directing/controlling framework of the management discipline. The paper is written by an engineer for an engineering readership, but it is hoped that it will find wider acceptance among chief executives and managers in industry generally.
Computer Prediction of Cyclic Excitation Sources for an External Gear Pump
Authors: Foster K , Taylor R , Bidhendi I M
Published: February 2007

A description is given of a computer program for investigating the performance of the external gear pumps under varying conditions with the special emphasis on the examination of pressure distributions within the pump, i.e. excitation forces for the vibration of the pump case and the variation in flow generated by the pump.

Measurements are presented for the variation with time of tooth space pressure and the results are compared with the theoretical predictions from the computer program.
The Manufacture of a New Generation of Headlamp Reflectors
Authors: Monk J F , Morgan L S
Published: February 2007

This paper reviews the development and implementation of a radically new manufacturing system for the production of advanced automobile headlamp reflectors using a thermosetting plastics material. The new system has replaced the traditional method which involved pressed and fabricated steel reflectors.

This project has required wide ranging interaction of many business functions. They include sales and marketing, material process and production research and development, product design and development, and factory production engineering. Product design in particular has benefited from the improved optical performance of the new reflectors, providing beams of a higher photometric output and having a more closely defined pattern. This has been achieved whilst product quality, durability and competitiveness have been improved. In addition, the high aspect ratio headlamps made possible by the plastics reflectors have allowed lower vehicle bonnet designs, resulting in lower coefficients of drag and thus improved fuel economy.
The Milton Keynes Alternative—A Case Study of Manufacturing Effectiveness
Authors: Farlam M
Published: February 2007

This paper is a case study of the installation of an automated manufacturing system in the Milton Keynes factory of Westland Helicopters. The financial and practical problems in producing components for helicopters are outlined and the decisions that were taken to solve these problems are described in detail. The benefits to the company in the form of increased productivity and reduced costs are reviewed.
A Methodology for Incorporating the ‘Company-wide’ Benefits of Material Requirements Planning within a Discounted Cash Flow Investment Analysis
Authors: Primrose P L , Hoey J , Leonard R
Published: February 2007

Although companies can obtain major benefits from material requirements planning (MRP) serious difficulties are usually encountered during the implementation phase. This paper highlights these difficulties and then goes on to show how they can be overcome if MRP is viewed as a ‘standard’ investment decision with quantifiable objectives. The financial evaluation techniques developed at UMIST are described and a comprehensive list of costs and benefits relating to MRP is given, with 76 factors being listed. These factors, selected to prevent double counting, ensure that each potential benefit is directly quantifiable, rather than being simply described as ‘positive but intangible’. The paper then goes on to describe a systematic method of defining and quantifying the benefits listed. Finally, because MRP represents a major investment decision, it is shown that the ability to conduct a comprehensive discounted cash flow (DCF) analysis enables the main savings to be identified, thereby ensuring that the implementation strategy can be designed to optimize both the operational and financial advantages.
The Application of Investment Appraisal to Aid the Evaluation and Implementation of Material Requirements Planning Systems
Authors: Hoey J , Primrose P L , Leonard R
Published: February 2007

This paper describes the application of the discounted cash flow (DCF) techniques for MRP evaluation, as discussed in the companion paper (1), by means of an ‘in-depth’ case study of a medium sized, small batch engineering company. The results demonstrate that the benefits of material requirements planning (MRP) are company-wide, and that when these benefits are quantified, the financial case for MRP is greatly strengthened. The paper also shows that MRP should not be viewed within the restricted concept of a technique which only improves shop floor efficiency. The use of the evaluation techniques within a number of major companies reveals that the ‘company-wide’ return on investment is much greater than has been previously suggested, and that the greatest potential benefits of MRP accrue outside production.
Front End Control Schemes for Pneumatic Servo-Driven Modules
Authors: Nagarajan R , Weston R H
Published: February 2007

This paper describes an approach which can be used to improve the dynamic characteristics of pneumatic servo drives. The approach is based on an outer decision loop which modifies the command issued to an existing closed loop drive. This outer loop is designed to generate a set of initial (front end) control sequences at the start of any ‘point-to-point’ move. A learning procedure is also incorporated in the scheme to obtain an optimized set of control parameters which can produce a specified quality of response.

The paper describes how the front end control scheme can be implemented in software, to improve the dynamic performance of microprocessor controlled pneumatically actuated robot modules which have been designed at Loughborough University and recently released in the UK market by Martonair Limited. Experimental results are presented which show that the scheme can improve the quality of response in terms of overshoot and positioning time.
The Performance of a Sealed Squeeze-Film Bearing in a Flexible Support Structure
Authors: Holmes R , Dogan M
Published: February 2007

In this paper attention is given to empirically modelling the hydrodynamics of a tightly sealed squeeze-film bearing in a flexible support structure simulating an aero-engine assembly, with a view to assessing its damping performance. It is found that predictable experimental results are obtained by employing an end-leakage factor which relates the outlet pressure around the bearing circumference to the corresponding ‘long-bearing’ pressure. The present work complements that covered in an earlier paper (1), which was concerned with the performance of an open-ended or weakly sealed squeeze-film bearing in a similar support structure.
The Influence of Experimental Variables on the Development and Maintenance of Wear-Protective Oxides during Sliding of High-Temperature Iron-Base Alloys
Authors: Glascott J , Wood G C , Stott F H
Published: February 2007

An investigation has been carried out into the development and maintenance of wear-protective oxide on iron-12 per cent chromium-base alloys during sliding in air at 20–600°C, with particular reference to the effects of temperature, of intermittent changes in temperature, and of sliding speed. It has been established that the wear-protective surface develops on and from compacted oxide and oxide-coated metal debris and involves deformation of the oxide. The wear process in the early stages of sliding generates metallic wear debris particles. These are fractured and re-fractured until they have a high surface to volume ratio. These surfaces are oxidized at the ambient temperature, to produce considerable amounts of oxide debris. Additional amounts are generated by transient oxidation of the specimen surfaces and removal of this oxide during each transversal of the sliding action. The rate of production of such oxide debris is determined by the ease of fracture of the metal debris and the rate of oxidation. Under these sliding conditions, this results in a minimum in the time required to generate a wear-protective oxide surface at 400°C. Development of such a surface takes a longer period at higher and lower temperatures, and indeed it does not develop at all at room temperature. Once established, the wear-protective oxide remains adherent and stable during isothermal sliding at 300°C and higher temperatures. Thermal stresses imparted by cooling to room temperature and reheating to 300° C do not cause loss of effectiveness of the oxide on subsequent further sliding at 300°C. However, subsequent sliding at room temperature results in rapid breakdown of the oxide and metal-metal contact, presumably due to a decrease in plasticity of the fine oxide debris with decreasing temperature or to a decrease in the adhesion between the oxide and the metal substrate or in oxide cohesion.
A Justification for the Wider Use of Fuzzy Logic Control Algorithms
Authors: Daley S , Gill K F
Published: February 2007

An investigation is described that attempts to demonstrate the benefits that can be gained by wider application of fuzzy logic control. The views presented are based on the control of a flexible communications satellite. Regions are identified in which the fuzzy logic controller's performance is superior to that of a classical design, when process mismatch is significant. Employing an approach incorporating Lyapunov's second method a parameter space is located where controller coefficients can be selected with relative confidence.
A Refined Numerical Solution for the Hydrodynamic Lubrication of Finite Porous Journal Bearings
Authors: Reason B R , Siew A H
Published: February 2007

A refined numerical solution for the hydrodynamic performance of finite porous journal bearings is presented. The solution takes into account the curvature of the bearing wall, interfacial slip of the fluid across the pore mouths, and employs the Reynolds boundary conditions at the oil film extremities. Based upon the results obtained, bearing design charts are shown for a wide range of L/D, ε and ψ values enabling design and performance characteristics to be evaluated for these bearings over and beyond the range normally required by the industrial engineer.
The Prediction of Liquid Film Journal Bearing Performance with a Consideration of Lubricant Film Reformation: Part 2: Experimental Results
Authors: Dowson D , Taylor C M , Miranda A A S
Published: February 2007

Analyses and design data for plain journal bearings rarely take into account the phenomenon of film reformation. The consideration of the re-establishment of the lubricant film after the cavitation region is difficult in a number of ways. The importance of allowing for reformation is, however, being increasingly recognized. This is particularly true as regards the satisfactory prediction of lubricant flowrate and the thermal operating characteristics of a bearing. The authors have previously implemented a cavitation algorithm to enable the cavitation region in a plain journal bearing to be located automatically and efficiently in a computer analysis. In Part I of the present paper theoretical results have been presented for the case of a plain bearing with a square-ended, axial groove located at the position of maximum film thickness. The second part of the paper gives details of an experimental investigation designed to establish the validity of the analysis.
An Integral Equation Method for Predicting Acoustic Emission within Enclosures
Authors: Francis D T I , Sadek M M
Published: February 2007

A method is presented for calculating the acoustic emission of a vibrating body within an enclosure whose surface has known absorption characteristics. It is based on a numerical solution of the Helmholtz integral equation. Solutions are given for the case of a pulsating sphere within a sphere, and good agreement with the exact analytical solution is reported. The method is of value for small and medium scale problems at lower frequencies, where traditional techniques are less reliable. It is also potentially less demanding computationally than finite element methods.