bluuebunny/crossref_metadata_2025 huggingface dataset:
Training in Advanced Engineering Design
Authors: Lickley Robert
Published: February 2007

Engineering design and the education and training of more high-calibre engineering designers to ensure an increased flow of advanced technology, high-quality products from British shores, is becoming critical. This is recognized by an increasing number of top managements in industry, the Science and Engineering Research Council, Department of Trade and Industry and other leading bodies in the country.

There is no doubt that comprehensive capable engineering designers cannot be produced solely from undergraduate courses and therefore urgent attention should be paid to establishing more postgraduate courses and other means of continuing education in advanced engineering design and development—including those which are project based—and to examine methods by which this might be achieved.

A discussion meeting with invited senior participants, held at the Institution of Mechanical Engineers, London, and chaired by Sir Robert Lickley, is reported.
Critical Influence of Distortion on the Thermal Resistance of a Pressed Contact
Authors: O'Callaghan P W , Probert S D
Published: February 2007

A suite of interactive computer codes has been composed to enable design engineers to predict the thermal resistance that a large heat flux encounters as a result of passing across the pressed contact between abutting surfaces. These surfaces are nominally flat when isothermal at normal ambient temperatures but distort under a thermal stress, arising due to the applied temperature gradient in a direction orthogonal to the interface, so that true contact occurs only over a disc rather than over the whole nominal contact area. The predictions have been corroborated by comparisons with previous experimental measurements. The evolved codes are capable of execution on commonly available desk-top computers.
On the Computation of Inertial Coefficients in Squeeze-Film Bearings
Authors: Ramli M D , Ellis J , Roberts J B
Published: February 2007

Inertial coefficients for full squeeze-film bearings are evaluated theoretically using Smith's differential equation relating fluid-film pressure to journal acceleration (1). The variations of the non-dimensionalized inertial coefficients with static eccentricity ratio in the radial and transverse directions are compared with some corresponding values obtained from Reinhardt and Lund (2) and Szeri et al. (3).

The results from these three methods show good agreement, especially for short bearings (that is bearings with low values of length–diameter ratio). However, Smith's approach has the advantage of computational simplicity and leads to fairly simple, asymptotic, analytical expressions for very short, and very long, bearings.
Identification and Modelling of Some Electrohydraulic Servo-Valve Non-Linearities
Authors: Arafa H A , Rizk M
Published: February 2007

An experiment is designed to investigate electrohydraulic servo-valves with mechanical feedback, excluding the effects of lap conditions and flow forces on the spool. Equilibrium of the armature–flapper assembly is modelled using exact expressions of the decentering magnetic torque on the armature and the hydraulic reaction on the flapper. Evidence is furnished that the feedback wire stiffness must not be constant as it is usually assumed. The parameters used to describe this hitherto unidentified non-linearity are accurately determined by computer simulation. This phenomenon is furthermore found to account for anomalies observed in the no-load flow gain characteristics of similar valves. Thus, a new criterion for quality and performance of electrohydraulic servo-valves could be established. Derivation of the stall-pressure gain characteristics of first-stage hydraulic amplifiers including a drain orifice is given in the Appendix.
The Calculation of Film Thicknesses in Soft, Highly Deformed Contacts under Dynamic Conditions
Authors: Hooke C J
Published: February 2007

In soft, highly deformed contacts the entry and exit regions form only a very small fraction of the total contact zone. This paper examines the behaviour of the film thickness in the remaining central region under dynamic conditions. It is shown that the influence of the pressure variations caused by the changes in film thickness is minimal and that they may be neglected without substantial loss of accuracy. This greatly simplifies the calculation of film thicknesses in these contacts and speeds their computation.
Performance of an Electromagnetic Bearing for the Vibration Control of a Supercritical Shaft
Authors: Bradfield C D , Roberts J B , Karunendiran R
Published: February 2007

The flexural vibrations of a rotating shaft, running through one or more critical speeds, can be reduced to an acceptably low level by applying suitable control forces at an intermediate span position. If electromagnets are used to produce the control forces then it is possible to implement a wide variety of control strategies.

A test rig is described which includes a microprocessor-based controller, in which such strategies can be realized in terms of software-based algorithms. The electromagnet configuration and the method of stabilizing the electromagnet force–gap characteristic are discussed. The bounds on the performance of the system are defined. A simple control algorithm is outlined, where the control forces are proportional to the measured displacement and velocity at a single point on the shaft span; in this case the electromagnet behaves in a similar manner to that of a parallel combination of a linear spring and damper. Experimental and predicted performances of the system are compared, for this type of control, where various programmable rates of damping are applied.
The Correlation of the Characteristics of Rough Surfaces with Their Friction Coefficients
Authors: Moalic H , Fitzpatrick J A , Torrance A A
Published: February 2007

Although a number of models have been suggested for relating the coefficient of friction of a surface with its profile characteristics, no firm experimental evidence to support a specific theory has been reported. In this work, the methods commonly used to calculate the characteristics of slope and curvature of a surface are investigated. The limitations of these methods are discussed and a new method for calculating the slopes and curvatures of a surface is recommended and shown to provide the most unbiased estimate for data limited by probe size. Finally, the results from preliminary tests show that the slope characteristics calculated using this technique are related to the friction coefficients of a surface as suggested by Challen et al. (1).
Active Suspension Control for an Off-Road Vehicle
Authors: Crolla D A , Horton D N L , Pitcher R H , Lines J A
Published: February 2007

After a review of recent developments in active suspension systems, a semi-active system fitted to an off-road vehicle is described. Theoretically predicted results are presented alongside data measured on the actual vehicle. The benefits of the semi-active system over a passive suspension are improved ride comfort and improved body attitude control.
Power Transmission Losses in V-Belt Drives Part 2: Effects of Small Pulley Radii
Authors: Childs T H C , Cowburn D
Published: February 2007

Run-in AV10 wrapped, raw-edged and cogged V-belts have been used to transmit power between pulleys of equal radii R equal to 51, 36 and 21 mm. Separate measurements of the torque and angular speed losses between the pulleys have shown that these are approximately proportional to 1/R and 1/R2 respectively and are also greater than expected from current theories. The maximum useful belt tension ratio fell from 21 to 5 as R was reduced from 51 to 21 mm.

A dimensionless belt deformation parameter (gEI/R4)1/2, arising from a simplified analysis of torque loss, has been found empirically to correlate with both torque loss and the speed loss in excess of that expected from belt extension and radial compliance.

Subsidiary tests with thick flat belts on cylindrical pulleys have shown their power losses to be unexpectedly close to those of V-belts of similar cross-sectional area, suggesting that those V-belt losses usually attributed to wedging in the pulley groove are of more general origin. It is speculated that belt carcass warping or shearing distortions must be considered to explain losses on small-radii pulleys.
Comparison of Methods for the Calculation of Mass Fraction Burnt from Engine Pressure—Time Diagrams
Authors: Stone C R , Green-Armytage D I
Published: February 2007

Calculations of the mass fraction burnt as a function of time in a spark ignition engine have been made by two methods. The simple method assumes that the mass fraction burnt is in proportion to the fraction of total pressure rise due to combustion.

The complex method assumes a two-zone combustion model, and computes the mass fraction burnt that is required to give the observed pressure rise for each 1° crank angle increment. The complex model allows for dissociation, variable gas properties and heat transfer from the burnt and unburnt gases.

Notwithstanding the substantial differences between the two models, the results are in surprisingly close agreement. This can be attributed to the fact that the temperature of the burnt gas remains nearly constant during combustion.
Danish State Railways Push-Pull Operation by Diesel and Electric Locomotives with Three-Phase Drive
Authors: Adelkvist V
Published: February 2007

In 1973 the Danish State Railways (DSB) began regular push-pull train operations with diesel-electric locomotives on the east coast line between Copenhagen and Elsinore. The internal train control system was based on transmission via a two-wire transmission line extending through the train. The transmission of information through the train between a driving-trailer coach and one or two locomotives, was accomplished by a digital technique. The push-pull service was gradually extended and now comprises all lines on Zealand.

In 1981 the new diesel-electric locomotives (class ME) with three-phase drive was put into push-pull service and 37 M E locomotives now perform the main part of the service (an average of 210000 km per locomotive per annum). The reasons for choosing three-phase locomotives, the experience gained with push-pull service, as well as the maintenance system and costs of maintaining three-phase drive locomotives in comparison with conventional diesel-electric locomotives are described.

DSB is carrying out electrification (25 kV, 50 Hz) of all lines east of the Great Belt. The push-pull service with electric three-phase drive locomotives (class EA) commenced in March 1986. The advantages of choosing three-phase drive in connection with the introduction of electrification with a 25 kV, 50 Hz system are discussed.

Class EA locomotives are equipped with a new generation of internal train control system based on a time multiplex system, which is able to transmit more information between locomotive and driving-trailer coach than the old system. Present experience regarding the push-pull service with class EA locomotives and the time multiplex control system is also described.
Considerations on the Use of d.c. and Three-Phase Traction Motors and Transmission System in the Context of Motive Power Development
Authors: Nouvion F F
Published: February 2007

This paper discusses proposals for using locomotives that are less damaging to the track and provide increased safety and reliability. It considers d.c. asynchronous and synchronous traction motors and how to get the best use out of them, and assesses the advantages and disadvantages of three-phase electric motive power.
Performance and Design Considerations for Dissipative Semi-Active Suspension Systems for Automobiles
Authors: Sharp R S , Hasan S A
Published: February 2007

Following previous work aimed at determining the relative performances of automobile suspension systems of passive, active and semi-active types by calculation, similar theoretical methods are applied here to evaluate a class of semi-active system that contains a passive spring of fixed stifness in parallel with the active damper. The static attitude control of the vehicle derives from the springs and in the cases considered the spring stiffness is adequate from this point of view. Systems based on two alternative forms of control law are studied. Results which show the best systems to offer particularly good performance for rough road conditions are presented. By adaptation of the damper control law using continuously updated information some capacity to obtain good performance under moderate conditions is shown to exist, but performance comparable with that obtainable from a purpose designed or fully adaptive system on average main road and motorway conditions is not possible.
Brake Pressure Apportioning Valves
Authors: Farr G P R
Published: February 2007

The increasing popularity of front wheel drive cars and the requirements of the European braking regulations have resulted in a corresponding increase in the use of brake pressure apportioning valves. These valves are suitable for conventional braking systems where the driver can push harder on the brake pedal, after the front wheels have locked, to obtain extra retardation from the rear wheels. However, the recent introduction of low-cost front-controlled anti-lock systems has limited the level of rear retardation and has made it necessary to optimize the braking utilization for all conditions of loading and road surface friction levels.
Railway Wheelsets—a Critical Review
Authors: Wise S
Published: February 2007

This paper gives a brief history of the evolution of wheelsets and then outlines the changes that have occurred in their design in the last 30 years, mainly due to the change to diesel and electric traction. Technical problems are discussed and the principal lines of research which have been followed are described. As a result, tyred wheel centres have largely been replaced by monobloc wheels with hardened treads, disc brakes have been introduced and the unmachined cast steel wheel has become a serious competitor to the traditional forged and rolled wheel. Of great importance is the introduction of computer analysis of wheel stresses which has led to modifications to the wheelset to reduce stress and to set limiting values.
Maritime Research and High Technology Development
Authors: Goodrich D
Published: February 2007

Are commercial pressures forcing the demise in this country of long-term maritime research projects or is privatization providing a much needed commercial focus for research and development programmes? This paper assesses the state of R and D in the British maritime industry and draws conclusions from other leading maritime nations and high technology industries. British Maritime Technology Limited (BMT) is in a unique position to provide an overview of the subject with its close links between industry, government and university research departments as well as international links with leading maritime nations. The experiences with BMT before and after privatization are drawn upon to make recommendations about the future structure and co-ordination of R and D programmes in the industry.
Basic Principles in the Design of Bled Steam Deaerator Systems for Industrial Steam Plants
Authors: Weir C D
Published: February 2007

This paper examines the basic principles governing the operational behaviour of the two types of deaerator systems best suited to the requirements of modern industrial steam plants of medium to large size. The two basic types of deaerator systems comprise a ranged pair of turbines with similar associated deaerators. Modulated control of the condensate level in the storage tanks provides an essential role in the steady state operation of the system. In the interests of clarity and brevity only the simplest possible cases have been considered and the more complex situations frequently encountered in practice require some adjustments to the procedures described.
Co-Generation in Arid and Cool Climates: A New Unified Perspective Using Exergy Analysis
Authors: Barclay F J
Published: February 2007

Co-generation plants are the norm in the arid climates of the Middle East, producing electricity and fresh water from the sea. In cool climates such as that of the United Kingdom combined heat and power, and district heating are under reappraisal. An attempt is made in the paper to use exergy theory to generate a new unified sense of proportion for these forms of co-generation. From the new perspective springs a realization of the benefits to network operation and investment which would flow from the development of a range of large vapour compressor heat pumps.

Doubt is cast on a concept, in current use, known as the ‘fuel utilization’ or ‘energy efficiency’. In the Middle East the concept has distorted co-generation system operation theory and capital investment principles. In United Kingdom documentation an unjustified aura of efficiency is ascribed to district heating, and condensing plants are wrongly denigrated.

The paper is an attempt to propagate ideas. Realization of those ideas is in the references or is deferred for later papers. It is important that qualitative thinking is correct before quantification begins.
Flameproof Diesel Engines in Underground Coalmines in Britain—design Features and Operational Experience
Authors: Currie J A N
Published: February 2007

The use of flameproofed diesel engines in underground mines of the British coalmining industry has a history approaching fifty years.

During that time, the design of the flameproof package has seen considerable changes, due both to normal evolutionary processes and to changes to statutory requirements, the most recent of which is the introduction of BS 6680 (1).

This paper briefly reviews the design changes that have occurred and describes the design features of typical current units. Today's units are inevitably more complex than those which were first introduced, owing to more stringent safety requirements; this has an impact on reliability and maintenance which is discussed, along with general operational experience.

The implications of the introduction of BS 6680 on future designs are also discussed, together with recent and current research and development aimed at reducing the size and cost of the flameproof unit.
Submarine Power Systems Using the V4-275R Stirling Engine
Authors: Nilsson H
Published: February 2007

The Stirling power module V4-275R, integrated with a liquid oxygen system, is currently built for submarines for the Royal Swedish Navy and for the offshore company Comex in France.

Since mid 1985 the Stirling engine system for the Swedish Navy has been successfully tested in a full-scale submarine test section. The next step in this programme will be an integration of the Stirling system into an operational Swedish submarine. A contract has been signed having Kockums as the main contractor.

The French programme means a 500 ton manned diver lock-out submarine, the SAGA I, which is under final construction at Comex in Marseille.

The energy system for the SAGA submarine consists of two V4–275R Stirling engines of maximum 100 kW power each. The oxygen storage, manufactured by AGA Cryo in Gothenburg, consists of two liquid oxygen tanks providing a total capacity of 10000 kWh, allowing the submarine to perform missions of up to 14 days submerged.
Training Placements for Sandwich Students in Small Companies: The Group Scheme for Technologist Industrial Training at Bradford University 1972–87
Authors: McArthur G M , Seale W J
Published: February 2007

Group Schemes for technologist industrial training were established in the early 1970s on the initiative of the Engineering Industry Training Board (EITB) to help small companies to take sandwich course students for single periods of industrial training. The Group Scheme at Bradford University has provided industrial training places for 40 students on the mechanical engineering course during the last 15 years, and the participating companies have recruited six graduates.

Details are given of the operation of the Scheme including recruitment, the provision of basic engineering training, and the response of small companies to changes in grant aid. The provision of grant aid has proved a critical factor in the readiness of a company to take a student.

The introduction of Engineering Applications 1 (EAI) and changes in funding from the EITB has altered the Group Scheme from a body offering sponsorship in a collective of small companies to one providing closely monitored training for ‘college-based’ students. The work of the Group Scheme could be improved by giving the EITB responsibility for encouraging engineering training in all industries.
Training and Skills for Computer Aided Design and Draughting
Authors: Riley P , Hannam R G
Published: February 2007

This paper presents and discusses the results of a survey of the training of users of computer aided design and draughting (CADD) systems. The survey sample was taken from selected companies using more sophisticated systems so that both the use and the training for use of a large range of software facilities were covered.

As with any new technology, CADCAM systems have necessitated their users learning new skills and this has to be provided by training. Training for CADD has significant implications for both industry and academe. Industry is often criticized for failing to train adequately and academe is criticized for failing to prepare graduates for industry. What is the appropriate training for CADD system users and what aptitudes are desirable? How effectively is industry training its personnel and how far should undergraduates be given CADD skills? These and related questions are discussed with reference to the results of the survey.
Experiences with a Teaching Company in the United Kingdom
Authors: Gibson P R
Published: February 2007

The paper contains details of a study carried out by the author while acting as an academic supervisor in a Teaching Company programme. Firstly, the structure and progress of the Teaching Company Scheme since its inception is reviewed. The study is then reported with the aim of identifying strengths and weaknesses within the programme. The views of the three parties involved in the programme (associates, academics and industralists), have been sought. The work shows that all three parties believe that they have much to gain from participation in the programme and also that account must be taken of a high level of commitment necessary for overall success. Finally, conclusions and recommendations are made which offer all three parties a general policy to adopt for the remainder of the programme.
A Self-Tuning Control Strategy for Gas-Fired Glass Forehearths
Authors: Bartlett H , Kochhar A K
Published: February 2007

This paper describes how a self-tuning feedforward-feedback control strategy could be implemented on a three-zone forehearth as used in the manufacture of glass containers. Experimental results, based upon real operating data, are presented in order to evaluate the control algorithm. It is shown how an existing model of a forehearth zone can be modified by the introduction of a self-tuning parameter, which enables the model to predict the glass surface temperature from the exit of any forehearth zone. The proposed control strategy for one zone of the forehearth is then modified to incorporate the self-tuning parameter, which makes it suitable for controlling each zone of the forehearth. Simulation results, using real operating data records, clearly show the effectiveness of the self-tuning parameter for the model as well as the control stategy.
Practice for the Sales Engineer
Authors: Cook A R
Published: February 2007

In this paper the author identifies some of the key skills to be used by industrial sales engineers and recommends strategy and tactics for their success. He gives advice on how to approach different types of buyers, on how to make an effective sales presentation, on the use of different types of questions and on how to close the order.
Aspects of Safety in an Advanced Handling System
Authors: Parker P D
Published: February 2007

‘Safety’ is a relative term and has different meanings in different situations. The use of the term ‘safety’ in relation to persons as distinct from damage to operating plant under abnormal conditions is discussed. Examples are given pertaining to an installation involving robots, conveyors and other handling plant where a man-machine interface is required for normal operation. The reliability of devices used to provide safety and the need to keep such devices foolproof is discussed. The paper also discusses the possibility of the creation of hazards by removing power from moving machinery in an emergency.
Further Refinement of an Anisotropic Model for Inclined Surface Solar Irradiation
Authors: Muneer T
Published: February 2007

An anisotropic model for predicting inclined surface solar irradiation has previously been reported by the author. The modelling exercise was furthered by analysing one-year measured hourly irradiation data, for five tilted surfaces, for Lerwick (60°08'N). The optimum values of the coefficients for Lerwick were found to be near those reported earlier for Easthampstead (51°23'N). The approach of separating sunlit surfaces from shaded ones and distinguishing between overcast and non-overcast sunlit surfaces was found to be fruitful again. A statistical test was employed for the validation of the isotropic and the presently proposed model for Lerwick. The isotropic model proved to be quite inadequate. The model now proposed was found to be adequate for the three cases although the plot between measured and computed sloped irradiation showed that the model for sunlit surfaces under non-overcast conditions could be further improved by incorporating the change of turbidity over the year. A similar plot prepared with Easthampstead data for an inclined surface reconfirmed the validity of the model established earlier.
Traction in Elastohydrodynamic Contacts
Authors: Hirst W , Richmond J W
Published: February 2007

The magnitude of the traction in elastohydrodynamic lubrication is influenced by at least two non-Newtonian effects. At very high pressures, the lubricant becomes noticeably viscoelastic and behaves as an elastic solid when the shear stress is small. At high values of the shear stress, the relation between the stress and the shear rate becomes non-linear and, when thermal effects are insignificant, conforms to the Eyring expression for viscosity. In general, however, the elastic region, the non-linear isothermal region and the thermal region are not separate and distinct but merge gradually into each other. This makes it difficult, experimentally, to determine the magnitude of the parameters controlling the behaviour of the fluid and, conversely, to predict from them the shape of the traction curve. The present paper examines these problems and shows that the major uncertainty is caused by the dearth of knowledge of the thermal properties of fluids at very high pressures. [These have been measured in an associated investigation by Richmond et al. (1).] It is shown that, when the correct values of the thermal properties are used and allowance is also made for the merging of the various regions of the traction curve, parameters may be derived from which the shape of the traction curve can be predicted within experimental error. In the non-linear region the Eyring relation is obeyed at pressures well above the usual glass transition pressure and it is concluded that in the extreme conditions of shear stress typical of elastohydrodynamic lubrication the glassy state is not achieved.
Experimental Determination of Squeeze-Film Dynamic Coefficients by a Frequency Domain Method
Authors: Roberts J B , Ramli M D , Ellis J
Published: February 2007

A frequency domain, forced vibration technique for obtaining estimates of the direct fluid damping, inertial and stiffness coefficients of a squeeze-film bearing is presented. The three coefficients are estimated through a linear, least-squares regression analysis performed on data obtained from a sequence of forced vibration tests, conducted using single sinusoids of differing frequencies. The method is applied to experimental data obtained from a squeeze-film damper with a central circumferential groove and no end seals. In addition to accurate estimates of damping coefficients, reliable estimates of inertial and stiffness coefficients are obtained.
Thermal Analysis of a Spur Gearbox Part 1: Steady State Finite Element Analysis
Authors: Joule D , Hinduja S , Ashton J N
Published: February 2007

The accuracy of previously published thermal analyses of machine tools has been severely limited by imprecise thermal boundary conditions, in particular the values and distribution of heat inputs and heat-transfer coefficients. This paper describes an attempt to overcome some of the difficulties by determining the thermal boundary conditions for calculating the temperatures in a gearbox using the finite element method.

A spur gearbox test rig has been designed and constructed, and a finite element model of the test gearbox developed. Temperature measurements and lubricant flow observations from experimental work have been combined with relevant theory to derive the boundary conditions. In the first part of this paper the experimental work and finite element steady state results are described. Sufficient agreement is evident between the two sets of results to indicate that the approach adopted here could be usefully extended to the analysis of other similar problems.
A Simple Algorithm for Self-Tuning Control of Low-Order Models
Authors: Magdy M A , Katupitiya J
Published: February 2007

A simplified approach to the design of self-tuning controllers or low-order systems is presented. The parameters of the continuous time system rather than the discrete time system are identified on-line using a recursive least-squares estimation algorithm. The estimated parameters are then used to calculate the controller parameters so that the system is forced to have a pre-specified closed-loop system performance. In some applications, adopting this approach reduces the number of parameters to be estimated. Further, the controller parameters are obtained using closed-form equations, thus avoiding the on-line solution of polynomial equations. An example is included.
Vibration Forces Produced by Waviness of the Rolling Surfaces of Thrust Loaded Ball Bearings Part 1: Theory
Authors: Wardle F P
Published: February 2007

Theoretical expressions are derived relating amplitude and wavelength of surface imperfections in thrust loaded ball bearings to vibration forces and frequencies produced under constant-speed operating conditions.
Forced Convection Air Cooling of an Array of Electronic Modules Using the Finite Element Method to Analyse Module Heat Transfer
Authors: Hardisty H , Abboud J , Vertman S
Published: February 2007

Because of the current trend in manufacturing to pack a greater number of electronic components into a given volume, the thermal failure of microelectronic systems is becoming an increasingly difficult design problem. This paper describes heat-transfer research into the important case of air cooling by forced convection of an array of electronic modules on a printed circuit board (PCB). Because of the interrupted nature of the airflow over the surface and the complex three-dimensional nature of the heat flow path, theoretical analysis is difficult and heat-transfer data for design are relatively scarce.

A research rig was designed and constructed which provided control of module power dissipation and continuously monitored the temperature of individual packages. An automatic data-acquisition system was successfully developed to record the large amount of experimental data that was generated. Realistic finite element models of the electronic package, leads and substrate were developed and used to reveal the temperature distribution. These models were also used, in conjunction with the experimental data, to determine heat-transfer coefficients. Correlations were established that related the value of the heat-transfer coefficient to distance from the leading edge of the PCB. It is intended that these correlations, together with the thermal analysis contained in the paper, will provide useful data for designers.
Two-Dimensional Elastohydrodynamic Lubrication Part 1: The Associated Dry Contact Problem
Authors: Hall R W , Savage M D
Published: February 2007

Associated with each elastohydrodynamic (EHD) lubrication problem there is a dry contact problem with the same contact zone, |x| a, surface displacement, υ(x), and pressure distribution, p(x).

This paper considers the two-dimensional dry contact problem and shows how Poritsky's closed-form solution can be used to derive results of fundamental importance to EHD lubrication. In particular, it is shown that singularities in pressure and pressure gradient arise from discontinuities in dυ/dx and d2υ/dx2. In addition, with υ(x) expressed as a Fourier cosine series of the form υ(x) = Σn Bn cos nη (where x = a cos η, 0 ≤ η ≤ π), it follows that at the end points of the contact zone, Reynolds boundary conditions are natural conditions yielding straightforward conditions on the Fourier coefficients, Bn.
A New Approach for the Determination of Cam Follower System Parameters
Authors: Baru M K , Ellis J
Published: February 2007

This paper reports a first investigation in the use of the state variable filter method of parametric identification in the determination of the mass, stiffness and damping content of cam follower systems. Simulated and real experimental data are processed by the technique with good results. Further developments are necessary (extension to higher order systems and inclusion of Coulomb damping) with the long-term aim of applying the results in the design and manufacture of dynamically tuned cams.
Dynamics of a Rigid Rotor Mounted on Discontinuously Non-Linear Elastic Supports
Authors: Neilson R D , Barr A D S
Published: February 2007

The equations of motion of a rigid rotor mounted at both ends in discontinuously non-linear supports and subject to excitation by arbitrary imbalance are presented. The methods used to solve the equations are described briefly and the responses obtained from the model and an experimental rig are discussed and compared. Good correlation is found. Over a range of shaft speed the presence of aperiodic responses characterized by spectral sidebands which diverge with increasing shaft speed is noted. An explanation of the mechanism generating these sidebands is advanced.
Automatic Formulation of Dynamic Equations of Motion of Robot Manipulators
Authors: Pan D , Sharp R S
Published: February 2007

Based on the use of homogeneous transformation matrices with Denavit-Hartenberg notation and the Lagrangian formulation method, a general computer program ROBDYN.RED for the symbolic derivation of dynamic equations of motion for robot manipulators has been developed and is discussed in this paper. The program is developed by using REDUCE, an algebraic manipulation language, and is versatile for open-chain structure robot manipulators with any number of degrees of freedom and with any combination of types of joint. Considerations are also given to saving computer memory space required for execution and to minimizing the runtime. Several examples are included to demonstrate the use of the program. Equations of motion in scalar form can be automatically transferred to FORTRAN format for later numerical simulations. The efficiency of the resulting equations in terms of numerical integration is also discussed and some further developments to improve the efficiency are suggested.
A Modular System for Transmission Error Measurement
Authors: Smith J D
Published: February 2007

A modular system of electronics for measuring transmission error with standard rotary optical encoders is described. The system can work flexibly with an overall speed range of the order of a 1000 to 1 by changing the order of the modules and will respond correctly to speed variations in both input and output of a synchronous drive such as a gear, chain or toothed belt drive.
Ideal Characteristics of a Variable Ratio Belt Drive
Authors: Bekircan S
Published: February 2007

A fundamental theory concerning the theoretical power-torque envelopes over the speed ratio range of a general variable ratio belt drive is presented, to the best of the author's knowledge, for the first time. This theory applies to both V and flat belt drives, and is independent of the detailed designs.

The analysis is based on two limiting factors, namely the maximum tension and the tendency of the belt to slip bodily on one or both pulleys assuming that the centre distance and the belt length are constant. These above factors determine the power and torque envelopes.

The most suitable envelopes for the design purpose of the variable ratio belt drive are those of compact size, maximum belt tension and relatively high transmitted power.
Investigation into the Effects of Suspension Characteristics and Design Parameters on the Performance of Tracked Vehicles using an Advanced Computer Simulation Model
Authors: Wong J Y , Preston-Thomas J
Published: February 2007

This paper describes the results of an investigation into the effects of the characteristics of the suspension system, initial track tension, vehicle weight and location of the centre of gravity on the tractive performance of tracked vehicles over unprepared terrain. The investigation was carried out using a newly developed computer simulation model NTVPM-86. The results show that the suspension characteristics, initial track tension and vehicle weight have noticeable effects on the mobility of tracked vehicles over marginal terrain, while the location of the centre of gravity, within the normal range, has a less significant influence on the tractive performance. It is demonstrated that the simulation model NTVPM-86 can play a significant role in the optimization of tracked vehicle design or in the evaluation of vehicle candidates for a given mission and environment.
Linear and Non-Linear Steady State Vehicle Handling
Authors: Dixon J C
Published: February 2007

The kinematic, primary and secondary handling regimes are analysed. The design factors contributing to the understeer gradient are reviewed and representative values for a modern car are presented. The effects of three types of differential are considered, as are tractive forces on free differentials, aerodynamic forces, the effect of load increments and the effects of turning radius. Secondary handling is investigated and the main contributing factors to the non-linearity of steer angle and attitude angle are quantfied.
Weight Distribution of Liquid Loads in Road Tankers
Authors: Allen R F
Published: February 2007

Axle loads for laden road tankers depend upon the configuration of the liquid tank. The paper determines the location of the centre of gravity of a liquid load in a tilted cylindrical barrel tank with dished and flanged ends and shows how the centre of gravity varies with the amount of liquid carried. The calculation permits greater accuracy in the determination of axle loads.
Performance Predictions for a Pneumatic Active Car Suspension System
Authors: Sharp R S , Hassan J H
Published: February 2007

A mathematical model of a pneumatic active car suspension system in a single wheel station form excited by realistic road roughness input is set up. The active control is exerted through a d.c. motor-driven air-pump.

The model is used to show that essentially all the advantages of active control, within the terms of reference, are obtained by employing the control only at low frequencies and having the suspension parameters adapt to the running conditions as they vary.

Control laws are derived using limited state feedback, linear stochastic optimal control theory and power consumption, and space requirements are evaluated. System performance is shown to be good in comparison with other known arrangements and encouragement for further work to extend the results is given.
An Experimental Technique for the Investigation of Three-Dimensional Stress in Bone Cement Underlying a Tibial Plateau
Authors: Little E G , O'Keefe D
Published: February 2007

The technique of experimental model testing was applied to the analysis of stress at selected sites in bone cement underlying a tibial plateau. The investigation utilized a large model knee fabricated from materials which had mechanical properties similar to the actual tibial plateau and acrylic cement but which did not duplicate adequately the complexity of bone. A porous interface was created in the model between the materials representing the bone and cement. Three-dimensional strain rosettes were embedded into the cement and the model was loaded in a varus or valgus mode. Overloading resulted in breakdown of the modelled anterior and part of the posterior cement-bone interfaces, producing non-linear and in some cases erratic strains in the anterior section but repeatable linear results in the posterior section. The investigation highlighted the necessity for three-dimensional strain gauge investigations as opposed to two-dimensional studies. It is suggested that the approach could provide comparative information about different products and form the basis for a valuable design tool.
A New Stretcher Design for Easy Manoeuvrability on Narrow Staircases and Rough Ground for Developing Countries
Authors: Guha S K , Anand S
Published: February 2007

Rough terrains with obstacles, narrow staircases and inadequate space to position the ambulance conveniently in relation to the exit door of houses, often encountered in developing countries like India, make it difficult if not impossible to carry patients using conventional stretchers. A novel two-wheeled stretcher to overcome the limitations has been designed, fabricated and tested for a decade. The special features allow even one stretcher operator to transport a patient over all types of ground, down staircases with landings so small as not to provide space for a regular stretcher to turn into and out from the ambulance. This wide range of facilities has been obtained by incorporating very simple and low-cost devices such as a metal guard over two wheels, friction belts and an ergonomically designed tie bar system. Usage in handling various medical and surgical emergency cases has proven the efficacy and acceptability of the design.
Methane Combustion in Laminar Diffusion Flames
Authors: Abam D P S
Published: February 2007

This paper is concerned with methane combustion in laminar diffusion flames. Data on methane concentration distributions in different diffusion flame geometries are correlated against a conserved scalar called mixture fraction. The correlation is used to determine a global methane combustion rate applicable in the rich to stoichiometric regions of laminar diffusion flames. The global rate is consistent with methane disappearance through the forward kinetic step:

CH4 + H → CH3 + H2

with [H] equilibrated according to

[Formula: see text]

on the rich side. This equilibration results from the three-body reaction

[Formula: see text]

which is equilibrated in the region 1.1 ≤ φ ≤ 2.74, 1300 K ≤ T ≤ 2000 K.

These results indicate that initial radical attack on the fuel molecule provides the rate-controlling step for methane combustion.
Alternative Engines—Curiosities or Competitors?
Authors: French C C J
Published: February 2007

This paper describes different types of engine used for transportation purposes. Some of the more interesting developments in spark ignition and diesel engines are outlined, but the paper is mainly a review of some of the alternative power plants that have been studied over the past 40 years. These include vapour cycle engines, free-piston engines, compound engines, Stirling engines, gas turbines, stratified charge engines, the catalytic engine, rotary engines and two-stroke spark ignition engines. The paper concludes by discussing possible future developments for some of these alternative engines.
Twisting of the Human Back in Forward Flexion
Authors: Hindle R J , Pearcy M J , Gill J M , Johnson G R
Published: February 2007

This paper addresses the role of torsion in the production of spinal injury and in particular the possibility of injury resulting from torsion combined with flexion. The back movement of 16 normal male subjects was measured using a non-invasive, three-dimensional measurement system for assessing spinal mobility, the opto-electronic CODA-3 scanner. Measurements were made of the ability to twist the back while standing upright and in two flexed postures. Rotational ability was shown, in general, to be increased in a flexed posture, presumed to be due to an opening of the lumbar zygapophysial joints. This suggests that twisting in a flexed posture could be a mechanism for intervertebral disc injury.
Design for Quality and Reliability
Authors: George B V , Board J A
Published: February 2007

The design approach to quality and reliability is described and the quality assurance arrangements and reliability analysis undertaken in support of Sizewell ‘B’ are described.
An Investigation into the Effect of Cyclic Loading and Frequency on the Temperature of Pmma Bone Cement in Hip Prostheses
Authors: Humphreys P K , Orr J F , Bahrani A S
Published: February 2007

A titanium alloy hip prosthesis was inserted in a Tufnol tube representing the upper part of the femur. The prosthesis was cemented in the model femur using PMMA bone cement. Five thermocouples were embedded in the bone cement and the assembly was subjected to cyclic loading with a range of 0.3–4.5 kN at a frequency of 6 Hz. Temperature measurements over a 48 hour period indicated that the temperature rise in the bone cement was less than 4°C. It is concluded that such tests can be carried out at 6 Hz without significantly affecting the mechanical properties of PMMA bone cement.
Subcapital Fracture in a Femoral Prosthesis: Brief Report
Authors: Macey A C , McManus F , Taylor D
Published: February 2007

Stem fractures in prosthetic femoral components are a well recognized problem. More recently neck fractures have been described (1). An unusual case of a ‘sub-capital fracture' in a femoral component is described.
A Comparison of the Application of ‘Energy from Municipal Solid Waste’ Technology in Three Countries—the United Kingdom, Sweden and Canada
Authors: Krol A A , Dent C G
Published: February 2007

The United Kingdom, Sweden and Canada are participants in an International Energy Agency programme designed to co-ordinate R and D activity on energy from waste (EFW) technologies. The scope and content of the individual national R and D programmes are a direct result of the different institutional, economic and environmental factors that govern application of such technologies in each country. A description of these factors is given together with an assessment of their influence in shaping the existing and likely future role of landfill gas, refuse-derived fuel and mass incineration in each country.
All Things to All Men
Authors: Ford Hugh
Published: February 2007

In this inaugural lecture Sir Hugh Ford discusses definitions of management and the modern connotations of the word. He questions whether management can be successfully taught to undergraduate engineers without ‘hands-on’ experience. He outlines the essential requirements for a good relationship between shop floor and management and differentiates between the management of people and the management of material resources. The current complexities of managing an engineering enterprise have prompted Sir Hugh to enunciate Ford's Law on shrinking time. He goes on to consider the financial aspects of engineering management and concludes by stating his own definition of the term ‘management’.