bluuebunny/crossref_metadata_2025 huggingface dataset:
The Reduction of Gear Pump Pressure Ripple
Authors: Edge K A , Lipscombe B R
Published: February 2007

Pressure fluctuations in a hydraulic system may be substantially reduced by cancelling the flow ripple produced by the pump. This paper describes a secondary flow ripple generating mechanism which introduces an equal and opposite flow fluctuation to that generated by the pump.

Tests have shown that the mechanism can virtually cancel four harmonics of pressure ripple but success is dependent on an accurate knowledge of the pump flow fluctuation characteristic. This is best determined experimentally.

Similar improvements can be achieved using a mechanism in a motor. This has the additional benefit of reducing torque fluctuations. The reduction in gear pump pressure ripple achieved with the mechanism has been shown to reduce overall airborne noise levels from a hydraulic system by as much as 10 dB, although the airborne noise radiated from the pump casing was not affected.
An Approach to the Design of Ideal Robotic Manipulators having Simple Dynamic Characteristics
Authors: Park H S , Cho H S
Published: February 2007

The dynamic characteristics of currently used, multi-degrees-of-freedom robots are too complex to analyse and thus it is not possible to design an implementable control algorithm. This paper proposes the guidelines to use in designing an ideal robot whose dynamics are much simpler than those of the conventional robot. It is shown that, even if the proposed design criteria are fulfilled with respect to the wrist only, the dynamic complexity can be drastically removed so that the conventional robot approaches very close to an ideal robot having simple dynamic characteristics. This paper further shows that the ideally designed robot dynamics can be very easily derived from Lagrangian formulation.
Surface Stress Measurements using Conical Oblique Pins on a Forging Die Mandrel
Authors: Tuncer C , Dean T A
Published: February 2007

Normal and friction stresses on a die mandrel were measured simultaneously using oblique pins when precision forging three different hollow shapes. The pins were conical to eliminate extrusion of the workpiece into the pin/bore clearance that occurs with previous designs. The variation of normal pressure and the direction of the friction force over the mandrel depends on the stage of die filling when a T-sectioned shape is forged. In general friction stresses approach the yield shear stress of the workpiece when the normal pressure becomes about twice the workpiece yield stress. Up to this value of contact pressure Amonton's friction law is applicable. Experimental results were found to be in good agreement with predicted ones.
Effects of Surface Roughness and Additives in Lubrication: Generalized Reynolds Equation and its Application to Elastohydrodynamic Film
Authors: Sinha P , Kennedy J S , Rodkiewicz C M , Chandra P , Sharma R , Prasad K R
Published: February 2007

To study the effects of surface roughness and additives in lubrication, a generalized form of Reynolds equation is derived by taking into account the roughness interaction zones adjacent to the moving rough surfaces as sparsely porous matrices and purely hydrodynamic film of micropolar fluid characterizing the lubricant with additives. A particular, one-dimensional form of this equation is used to study these effects on the elastohydrodynamic (EHD) minimum film thickness at the inlet, between two rough rollers. It is shown that for the low permeability of the roughness zone, the EHD film thickness increases as the mean height of the asperities increases, whereas for the high permeability it decreases. The EHD film thickness is also found to increase with the concentration of the additives and the molecular size of the particles. These results are in conformity at least qualitatively, with various experimental and theoretical investigations, cited in the paper.
Plane Stress Vibrations in Rotating Discs
Authors: Burdess J S , Wren T , Fawcett J N
Published: February 2007

The general in-plane response of a rotating disc is considered. Forward and backward travelling circumferential waves occur and are shown to have velocities that depend upon the disc speed Ω. The orthogonality and stability of these waves have been determined. The motion caused by externally applied body forces is calculated and used to predict the conditions that give resonance.
Thermodynamic Design of Stirling Cycle Machines
Authors: Organ A J
Published: February 2007

When local, instantaneous departures from ideal reversible behaviour are evaluated in terms of the entropy generation rate, the differential equations describing the unsteady processes in the Stirling cycle machine give way to steady flow forms. A simple multiplication by To gives immediately the local, instantaneous rate of loss of available work. The paper exploits this fact to obtain, from an ideal model of the flow processes, the indicated cycle work of the real (irreversible) cycle. The result is of the form:

[Formula: see text] {( geometric parameters), τγ, NRE, NPR, NF, … ( dimensionless groups in order of diminishing influence)}

where τ, NRE, NF etc. are dimensionless groups of the operating parameters, engine speed, pref, Te, Tc etc. and γ is the specific heat ratio of the working fluid, which is shown to be the only fluid property that independently influences Z.

The approach is an alternative to the time consuming solution of the defining differential equations and provides a convenient design tool which has long been lacking in this area. The only assumption additional to those invoked in conventional computer modelling of the Stirling cycle is that actual gas processes do not depart excessively from those predicted by the ideal model of the flow—for example from those provided by the so-called ‘adiabatic’ cycle model.
Gear Transmission Error Accuracy with Small Rotary Encoders
Authors: Smith J D
Published: February 2007

Two small (90 mm) angle encoders were tested back to back to assess sizes of high-frequency components of error. The results showed errors well below 0.1 seconds of arc at the rotation multiples likely to be relevant for gear noise and vibration testing.
The Influence of Surface Roughness on Elastohydrodynamic Traction
Authors: Evans C R , Johnson K L
Published: February 2007

If the ratio λ of the nominal elastohydrodynamic film thickness h0 to the root-mean-square roughness is greater than about 5, the traction between two rolling and sliding surfaces is negligibly influenced by surface roughness. The traction is then primarily a function of the parameter α0[Formula: see text], as described in reference (4), where[Formula: see text] is the mean contact pressure and αo is the pressure–viscosity index of the lubricant. When λ lies in the range 0.5–6, it is shown that the effect of asperity interaction is for the traction to still be governed by the bulk rheological properties of the oil, but at a pressure corresponding to the mean contact pressure of the asperities.
Estimation of the Linearized Damping Coefficients of a Squeeze-Film Vibration Isolator
Authors: Stanway R , Firoozian R , Mottershead J E
Published: February 2007

In this paper the authors present experimental confirmation of the feasibility of a new approach to the estimation of the four damping coefficients associated with a squeeze-film vibration isolator. The design and construction of the experimental facility is described in detail. A time-domain filtering algorithm is applied to process the displacement responses to single-frequency excitation and thus extract information on the linearized dynamics of the squeeze-film. The estimated coefficients are validated by comparing performance predictions with those obtained from spectrum analysis and from short-bearing theory. The significance of the results is discussed and suggestions are made for further work in this area.
Measuring Surface Temperatures between Rolling Steel Cylinders Using Double-Layer Transducers
Authors: Baumann H
Published: February 2007

The signals of the thin-film transducers previously used for the measurement of temperature distributions in elastohydrodynamic contacts have been influenced by the high pressures occurring. At pure rolling conditions when the temperature increase is small, the error caused by pressure reaches nearly the order of magnitude of the temperature signal to be recorded. Using double-layer transducers of a novel type, a reduction of this error of over 90 per cent can be achieved. In this paper temperature measurements at pure rolling conditions are described. It has been shown that a distinct temperature spike occurs at the constriction at the trailing edge of the elastohydrodynamic contact.
A Study of Vortex Throttles Part 1: Experimental
Authors: Priestman G H
Published: February 2007

Measurements have been made to determine the performance of various designs of vortex throttle using both air and water. Two basic types of throttles were used, square-edged and round-edged. Performance is expressed mainly in terms of Reynolds number and Euler number. The effect of changes in geometry on performance is studied and comparison made between performance for compressible subsonic flow and for incompressible non-cavitating flow. The maximum values of Euler number found for throttles with a unity tangential to axial port area ratio were about 66 for square-edged throttles and about 71 for round-edged throttles. The results agree with those of Zobel, although better performance than found by Zobel was obtained with a slightly modified axial port geometry. In one case severe cavitation was found to slightly improve throttle performance, with the indication that a throttle could be made with performance independent of cavitation. Some recommendations are given for optimum throttle design.
On the Implementation of an Adaptive Hybrid Position/Force Control for Manipulators
Authors: Eun T , Cho H S
Published: February 2007

Hybrid position/force control is an effective tool for carrying out a task whose geometry constrains the position of a manipulator. This paper presents a task-oriented architecture for hybrid control, taking into consideration the complexity of the manipulator dynamics and uncertainties in the external constraints. For this purpose an adaptive pole assignment self-tuning algorithm was adopted based upon six independent decoupled ARMA models which represent position and force dynamics of manipulators in the task-oriented coordinate frame. To complete the control architecture, a control input transformation algorithm and an output synthesizing algorithm were developed in the task-oriented frame. These algorithms were designed to be easily transformable between coordinate frames in order to be applicable to a variety of tasks. To demonstrate the validity of the architecture, three example tasks were simulated using a manipulator whose kinematic and dynamic characteristics are analogous to those of a Puma 560 industrial robot.
Excess Streamwise Vorticity and Its Role in Secondary Flow
Authors: James P W
Published: February 2007

The purpose of this paper is, firstly, to show how the concept of excess secondary vorticity arises naturally from attempts to recover three-dimensional flow details lost in passage-averaging the equations governing the flow through gas turbines. An equation for the growth of excess streamwise vorticity is then derived. This equation, which allows for streamwise entropy gradients through a prescribed loss term, could be integrated numerically through a blade-row to provide the excess vorticity at the exit to a blade-row. The second part of the paper concentrates on the approximate methods of Smith (1) and Came and Marsh (2) for estimating this quantity and demonstrates their relationship to each other and to the concept of excess streamwise vorticity. Finally the relevance of the results to the design of blading for gas turbines, from the point of view of secondary flow, is discussed.
Flow in Collecting Conduits
Authors: Hager W H
Published: February 2007

Steady conduit flow with spatially increasing discharge is analysed by a hydraulic approach. Particular attention is paid to the effects of viscosity, wall roughness, additional head-loss due to the lateral inflow and the lateral inflow intensity on the flow characteristics in the manifold. The governing system of equations is presented for collecting manifolds consisting of a large number of laterals and solved for prismatic perforated collecting pipes. The comparison with observations indicates a good agreement. Finally, collecting conduits by which uniform lateral inflow is achieved are discussed.
An Energy Method for the Identification of Mechanisms of Castor Instability with Particular Application to Motorcycles
Authors: Raines M , Thorpe T E
Published: February 2007

Castor instabilities are a serious problem in several areas, particularly in motorcycle design. A clear understanding of the mechanisms of instability is necessary before the problem can be overcome. This paper describes a technique for assessing whether or not a particular mechanism can give rise to instabilities, and it is used to identify three new possible sources of wheel shimmy.
Performance of a High-Reduction Planetary Gear Drive with Respect to Efficiency
Authors: Bekircan S
Published: February 2007

This paper presents some of the general practical problems involved in the design of a high-reduction compound planetary gear drive and examines such a drive for high speed ratio, power circulation and efficiency. The performance of the drive with respect to efficiency of 50–60 per cent has been obtained under various running conditions such as speed, load and temperature. An attempt was also made to balance internal forces in order to increase efficiency. At first sight, the number of factors involved appears to make it impossible for a general analysis of the problem to be made, but broad conclusions have been drawn.
Leakage Through Loaded Flat-Flanged Joints without Gaskets
Authors: Fessler H , Hyde T H , Lewis L V
Published: February 2007

Experimentally determined air leakage data are interpreted using fluid flow theory, finite element deflections and initial gap measurements. It is shown that laminar flow equations do not apply at practical aero-engine pressures and that the leakage flow can be overestimated by assuming choked isentropic flow at the outside diameter of the joint. Design against leakage is thereby reduced to a structural consideration of gap height at the outside diameter. It is shown that the gap height will usually reduce with load. A ‘divergent’ initial gap is shown to cause excessive leakage. However, the machining of a very small cone angle on the contact face is shown to be an effective method of significantly reducing leakage.
The Selection of Fan Blade Geometry for Optimum Efficiency
Authors: McKenzie A B
Published: February 2007

A method for selecting C5 circular arc camber aerofoils for optimum efficiency is described. The results for a typical design are presented and compared with the carpet plot method of Hay, Metcalfe and Reizes.
A High-Speed Direct Injection Diesel Engine for Passenger Cars
Authors: Stephenson J A , Hood B A
Published: February 2007

The paper describes the development of a high-speed direct injection (HSDI) diesel engine suitable for passenger car applications. The evolution from a low emissions medium-speed engine, through a four-cylinder 2.3 litre research engine, into a four-cylinder 2.0 litre production engine is presented. The challenge to the engineer has been to develop the HSDI engine to operate with acceptable noise, emissions, smoke and driveability over the wide speed range (up to 5000 r/min) required for passenger cars. The key element in this task was the optimization of the combustion system and fuel injection equipment. The HSDI is shown to have a significant fuel economy advantage over the prechamber indirect injection (IDI) engine. Future developments of the fuel injection system are described which will further enhance the HSDI engine and provide additional noise and emissions control.
Optimizing the Co-Generation Coefficient in District Heating and the Co-Generation of Heat and Electricity
Authors: Cui S Q , Wu X S , Qu Y
Published: February 2007

The co-generation coefficient a plays an important part in district heating. In order to save more primary energy and obtain comprehensive benefits, α3 must be optimized in design.
Engineering Leadership in the Boardroom
Authors: Barlow William
Published: February 2007

This paper outlines the qualities required for leadership and demonstrates how engineers may develop these qualities in the course of their work. Contrary to currently held beliefs, engineers are frequently to be found in the boardrooms of large British companies, and examples of how engineering leadership has contributed to successful projects are given. The consequences of the lack of engineering leadership in the Government and its effect on the national economy are discussed.
Case Studies of Quality-Related Costing in Engineering Manufacture
Authors: Plunkett J J , Dale B G
Published: February 2007

As part of a research project on the determination and use of quality-related costs, case study work has been carried out at four manufacturing companies. This paper presents the major findings from each case study. A measure of the status of quality costing is that it is not featured in the quality manuals at any of the four companies. The aspects of quality which will need to be developed if the subject is to be raised to the level enjoyed by other major business parameters are outlined.
Manufacturing Quality Assurance—A Systematic and Logic Approach to Effective Engineering Management
Authors: Patel B M
Published: February 2007

In today's increasingly competitive and diversified business markets, industries are continually striving for a high degree of customer satisfaction through product and service reliability at economical costs.

Modern practices are now directed towards the use of harmonized, national and international standards such as BS 5750/ISO 9000 series which provide generic guidelines to developing quality systems as an integral part of successful business management strategies. This paper highlights the management, systems and manpower (human resources) aspects of an organization that can provide effective means of controlling and managing the manufacturing engineering function of quality assurance activities within a company.
The Examination of Optimal Focus Settings with Material Thickness at Atmospheric and Subatmospheric Pressures of Air and Oxygen in Laser Drilling of Metals
Authors: Yilbas B S , Begh F
Published: February 2007

Previous statistical examination of relevant factors in laser drilling has shown that the focal settings, material thicknesses and drilling ambient pressure had a significant effect on the resultant hole geometry, but left open the question of which combination of factors gives optimum drilling. Consequently, the present work examines the optimum focal settings with material thicknesses at atmospheric and subatmospheric ambient pressures of air and oxygen for different materials. The results obtained show that the optimal setting reduces as material thickness increases at all ambient pressures.
The Influence of Process Variables on Load and Accuracy When Forging in a Completely Closed Cavity Die
Authors: Ibhadode A O A , Dean T A
Published: February 2007

The effect of die design, billet location, billet volume variation, billet geometry, friction and die expansion, on forging loads and forged dimensions are investigated, for solid cylinders forged in completely closed die cavities.

Forging tests were carried out on both a 2000 kN mechanical press and a 3000 kN hydraulic testing machine using BS 080M40 steel and commercially pure aluminium.

The results show that the above factors can significantly affect forging load requirements and die cavity filling. They provide a basis of information for commercial development of net-shape or near-net-shape forging processes.
Two-Dimensional Thermodynamic and Flow Analysis of the Simple Hot-Air Engine
Authors: Organ A J
Published: February 2007

Attention focuses on the annular gap between displacer and cylinder shell as the gas passes between expansion and compression spaces. Equations are formulated for velocity and temperature distributions as a function of time and the distance coordinate directions—radial and axial. Local, instantaneous entropy creation rates due to viscous dissipation and heat transfer are computed without the need to refer to the usual friction factor and coefficient of convective heat transfer. From considerations of exergy an estimate of indicated thermodynamic work per cycle follows. This is expressed in terms of performance maps covering the entire range of possible speeds, charge pressures and sizes for a machine of given geometry.
Theoretical Road Damage Due to Dynamic Tyre Forces of Heavy Vehicles Part 1: Dynamic Analysis of Vehicles and Road Surfaces
Authors: Cebon D
Published: February 2007

Theory is presented for simulating the dynamic wheel forces generated by heavy road vehicles and the resulting dynamic response of road surfaces to these loads. Sample calculations are provided and the vehicle simulation is validated with data from full-scale tests. The methods are used in the accompanying paper to simulate the road damage done by a tandem-axle vehicle.
Superconductivity: Scientific Phenomenon to Engineering Reality
Authors: Dew-Hughes D
Published: February 2007

This paper gives a brief description of the phenomenon of superconductivity and its early history, and then outlines what is required of a superconductor in order that it can be used in an engineering device. The development of practical materials to meet these requirements, with examples of applications, is then given. Finally, in the light of the recently well-publicized spectacular discoveries of new ceramic superconductors, the author speculates on their probable impact on engineering.
Cavity Cloud Formation and Generation of Stringy Damage Patterns in a Polymer Solution
Authors: Nanjo H , Shima A , Tsujino T
Published: February 2007

Cavity cloud formation and generation of stringy damage patterns on an aluminium specimen in a polymer solution were studied using a vibratory cavitation facility. It is shown that few bubbles are seen on a specimen although numerous bubbles appear at a place several millimetres away from the specimen. Since a polymer solution may behave elastically due to the relaxation effect, the solution can follow the vibration of the specimen. Therefore the pressure on the specimen in the polymer solution does not fall to as great an extent as in water, and so consequently fewer bubbles form. Stringy damage patterns originate from cracks on the specimen surface or impurities in the polymer solution adjacent to the specimen. It is also shown that the addition of polymer greatly affected the damage rate.
Performance Assessment of an Impact Rig
Authors: Birch R S , Jones N , Jouri W S
Published: February 2007

A recent upgrading of a drop hammer rig was carried out and a series of calibration tests established the energy losses in the existing anvil. Both the test results and the mathematical modelling showed that significant energy losses would occur at high impact loads. An alternative anvil design considerably reduced the energy losses and improved the performance of the drop hammer rig.
Vibration Forces Produced by Waviness of the Rolling Surfaces of Thrust Loaded Ball Bearings Part 2: Experimental Validation
Authors: Wardle F P
Published: February 2007

Experimental vibration measurements of a system containing a single ball bearing are compared with theoretical predictions based upon the model described in Part 1 and measurements of system transfer functions. Agreement between theory and experiment is reasonable.
Two-Dimensional Elastohydrodynamic Lubrication Part 2: Solution of the Line Contact Problem
Authors: Hall R W , Savage M D
Published: February 2007

Following Part 1, this paper describes a method for solving the line contact problem in elastohydrodynamic lubrication. Using results derived in Part 1 together with the Reynolds lubrication equation and boundary conditions, an iterative scheme is designed so as to yield pressures, displacements and film thicknesses within a parabolic, lubricated contact. Converged numerical solutions are readily obtained over a parameter range which includes both isoviscous and weakly piezoviscous contacts.
The Evolution of Locomotive and Rolling Stock Maintenance Schedules
Authors: Butler A W
Published: February 2007

The paper introduces the maintenance schedule as an integral part of the controls for planned maintenance and reviews the historical development of locomotive maintenance schedules and specifications within British Railways (BR). The events which led to the publication of maintenance schedules for locomotives and rolling stock in a variety of formats and content are explained, culminating in the 1985 decision to produce all such future documents to one standard, taking account of simplification of use at BR depots, the new maintenance policy and the benefits of computerization. The purpose of the maintenance schedule and its supporting documents is redefined in relation to the new maintenance strategy of BR and a new rationale introduced. The standard format is confirmed and the mechanisms for ensuring its maintenance explained.

Future requirements associated with development of standard job descriptions, decoupling component overhauls from body overhauls assisted by a computerized maintenance schedule and the changes in overhaul specification promoted by BR's developing contract overhaul policy are described in detail.
Agility and Manoeuvrability as Passive Defence for Armoured Vehicles
Authors: Sher E , Refael S , Luria D
Published: February 2007

A mathematical model is presented and applied to investigate the relationship between the automotive performance and manoeuvring of an armoured vehicle and the probability of its being hit by tank gunfire. The model takes into consideration the type of ammunition, the characteristics of the fire control system and the automotive route of the target. Three cases were examined: a stationary target, an accelerating target and a target moving over a winding course at a constant speed. The model has been calibrated to fit a set of experimental results.
Stepper Motors: Principles and Characteristics
Authors: Cooke J R
Published: February 2007

The basic principles of stepper motors are explained. Under certain circumstances it is shown that a stepper motor may be a better option than a servo motor. The three most common types of stepper motor are described and their important characteristics are illustrated and explained. Finally, the principles of stepper motor drives and the various types available are analysed.
Reinforcement of Bone Cement Using Metal Meshes
Authors: Taylor D , Clarke F , McCormack B , Sheehan J
Published: February 2007

Following on from previous work reported in this journal, a practical system has been developed for in situ fibre reinforcement of bone cement in the hip joint prosthesis. A fibre preform is inserted during the operation, surrounding the metal stem of the prosthesis, forming a composite with the cement. Tests performed on full-scale models of the joint show improvements in fatigue life by more than an order of magnitude when a preform of metal fibres is used; this significantly delays the onset of cement cracking and stem loosening. Initial results reported previously suggest that other fibre materials such as carbon may give even greater improvements. Clinical trials have begun, using a form of the metal mesh.
Intake Pipes Evaluation: Comparison between Paddle-Wheel and Hot-Wire Anemometry Methods
Authors: Desantes J M , Benajes J V , Lapuerta M
Published: February 2007

The aerodynamic behaviour of the intake pipes of direct injection diesel engines has usually been quantified by means of swirl number and the discharge coefficient. In order to validate these parameters an experimental method based on the hot-wire technique has been applied to the steady flow rig where the former parameters are measured. This method allows the measurement of the three components of the velocity referred to an orthogonal coordinate system by placing the probe parallel to these three directions. The results obtained are presented and analysed in this paper. The comparison between the two measurement techniques has been done in terms of discharge coefficients, angular momentum flux and paddle-wheel speeds, calculated by integration of the measured velocity field in the case of the hot-wire results. The comparison between the values of the angular momentum flux allows the conclusion to be made that some of the hypotheses assumed by the paddle-wheel method are not accurate.
The Determination of Diesel Engine Friction Characteristics by Electronic Cylinder Disablement
Authors: Haines S N M , Shields S A
Published: February 2007

The use of electronically controlled unit injectors on a high-speed direct injection diesel engine has allowed the development of a new technique for measuring motoring losses. The digital engine controller is programmed to skip successive numbers of injections in a specific circulating sequence, while dynamometer load is adjusted to maintain the desired speed. The linearity between required brake torque and the proportion of disabled to normal injection cycles permits extrapolation of results to find the negative load that would be required to motor the engine at that speed. The method appears to yield more reliable results than traditional approaches, and gives hot motoring values of mean effective torque without the need for external heating or a motoring facility. The equipment and method involved are described, and readings obtained for the whole speed range are presented. These are correlated with losses estimated from pressure measurements, and compared with friction characteristics produced by alternative techniques.
Strain Gauge and Photoelastic Evaluation of the Load Transfer in the Pelvis in Total Hip Replacement: The Effect of the Position of the Axis of Rotation
Authors: Miles A W , McNamee P B
Published: February 2007

Aseptic loosening of the acetabular component is the principal long-term complication in total hip replacement. Radiographic evidence suggests a higher incidence of loosening with medialization of the axis of rotation of the acetabular cup. A simplified two-dimensional photoelastic investigation of the load transfer in the pelvis demonstrates that the stress distribution is substantially changed when this axis of rotation is medialized. Strain gauge measurements on three dry hemi-pelvic bones confirm this effect. It is postulated that the redistribution of load resulting from medialization may result in inadequate skeletal support for the acetabular component predisposing to loosening.
Stability of Feedback Control of Boost in Variable Geometry Turbocharged Automotive Diesels
Authors: Backhouse R J , Franklin P C , Winterbone D E
Published: February 2007

This paper is concerned with the control of turbocharged automotive diesel engines fitted with variable geometry turbines, in particular, for the case where a feedback loop is used to control the boost pressure. Interaction between the loops governing speed and controlling boost will affect the stability of the overall system.

The effect of this interaction is considered for the case of automotive diesel engines in the 200–250 kW class at peak torque speed, both with and without engine speed governing, and for the cases of idle and maximum speed governing. The effects of vehicle load, turbo-charger rotor inertia and actuator response are also considered.

The analysis uses the characteristic equation of the control system to determine lines of system instability in the gain plane.
Calculation of the Flow in a Sector of an Annular Combustor
Authors: Jones W P , Sodha M N , McGuirk J J
Published: February 2007

Calculations have been made of the isothermal flow field within a sector of an annular combustion chamber representative of the type to be found in small gas turbines. The complex combustor geometry is described using a Cartesian finite difference mesh within which the physical domain boundaries are represented in a piecewise linear fashion. The k-s turbulence model is used to describe turbulent transport. Overall the calculated and measured flow fields are found to be in reasonable agreement and in the primary zone measured velocity profiles are reproduced to within an acceptable accuracy.
Optimum Design of Radial-Flow Impellers
Authors: Ray G S , Sinha B K , Majumdar S
Published: February 2007

The paper presents a procedure of computer aided design of high-speed impellers. The configurations are obtained using programs for the strength under the influence of centrifugal force within given constraints. The method provides a tool for optimizing stresses at an early design stage.
An examination of the Throughflow of Nucleating Steam in a Turbine Stage by a Time-Marching Method
Authors: Bakhtar F , Bamkole B O
Published: February 2007

The paper describes a theoretical treatment for nucleating throughflow of steam in a turbine stage. The conservation equations governing the overall behaviour of the fluid are combined with those describing droplet behaviour and treated by a time-marching method. The computer program developed has been applied to some test cases and comparisons are presented between solutions allowing for non-equilibrium effects and those in which steam has been assumed to remain in thermodynamic equilibrium.
Transient Vibrations Caused by Heel Strike
Authors: Smeathers J E
Published: February 2007

Transient vibrations caused by heel strike and travelling vertically through the body have been monitored using accelerometers taped to the skin. A correction for skin movement based on the transmissibility function is described. The average velocity between the foot and the head for the heel-strike transient is 220 m/s. This velocity is greatest in the legs, 610 m/s, and least in the spine, 90 m/s. Shock absorption occurs mainly in the legs and to a lesser degree in the spine.
Shock Absorption by the Spinal Column in Normals and in Ankylosing Spondylitis
Authors: Helliwell P S , Smeathers J E , Wright V
Published: February 2007

The transmission of heel-strike vibration using skin-mounted accelerometers was measured in normal subjects and subjects with ankylosing spondylitis. In normal subjects transmissibility was enhanced between 5 and 13 Hz and attenuated at frequencies above 15 Hz. In ankylosing spondylitis transmissibility was enhanced at 4 Hz but less so between 5 and 13 Hz and little attenuation was observed at the higher frequencies. This difference is expected in view of the pathological changes occurring in the spinal column in ankylosing spondylitis. The results support the hypothesis that the normal spinal column has to bend in order to absorb vibrations with a frequency greater than 15 Hz.
A Technique for Quantitative Assessment of Three-Dimensional Motion with Applications to Human Joints
Authors: Reddy N P , Askew M J , Baniewicz F M , Melby A , Fuller K A , Steurer P A , Herr J E , Sheffer D E
Published: February 2007

A technique is developed for quantitative measurement of general three-dimensional motion, and this technique is applied to the kinematics of anatomical joints. The spatial locations of three orthogonal points representing coordinate frames on each member of the joint are measured during motion of the joint by photo encoders of a three-dimensional mechanical pointer. Kinematic calculations are used to derive, from the experimentally collected data, the six orthogonal components of the motion of one member relative to the other. The accuracy of this technique is presented. Applications to the knee and ankle are discussed.
The Geometry of the Knee in the Sagittal Plane
Authors: O'Connor J J , Shercliff T L , Biden E , Goodfellow J W
Published: February 2007

A geometric model of the tibio-femoral joint in the sagittal plane has been developed which demonstrates the relationship between the geometry of the cruciate ligaments and the geometry of the articular surfaces.

The cruciate ligaments are represented as two inextensible fibres which, with the femur and the tibia, are analysed as a crossed four-bar linkage. The directions of the ligaments at each position of flexion are calculated. The instant centre, where the flexion axis crosses the parasagittal plane through the joint, lies at the intersection of the cruciates. It moves relative to each of the bones during flexion and extension. The successive positions of the flexion axis relative to a fixed femur and to a fixed tibia are deduced. The shapes of articular surfaces which would allow the bones to flex and extend while maintaining the ligaments each at constant length are calculated and are found to agree closely with the shapes of the natural articular surfaces. The calculated movements of the contact point between the femur and the tibia during flexion also agree well with measurements made on cadaver specimens.

The outcome is a geometric simulation of the tibio-femoral joint in the sagittal plane which illustrates the central role played by the cruciate ligaments in the kinematics of the knee and which can be used for the analysis of ligament and contact forces.
Fatigue of Composite Materials
Authors: Curtis P T , Dorey G
Published: February 2007

This paper reviews the area of fatigue of composite materials, particularly fibre-reinforced plastics, used in aerospace and other industries. The review concentrates on carbon, glass and aramid reinforcing fibres and epoxy resin as a matrix material. Mention is also made of newer matrices such as those based on thermoplastics.
Landing Gear Design and Development
Authors: Jenkins S F N
Published: February 2007

This paper discusses design requirements and the compatability of shock absorbers to satisfy the performance required. The effect on landing gear design of trends to use the latest materials, particularly ultra-high-tensile steels, also test methods to confirm stress analysis calculations and flight-by-flight fatigue testing.
Automatic Determination of Work-Holding Parameters for Turned Components
Authors: Hinduja S , Huang H
Published: February 2007

This paper describes the development of SETUP which is one of the modules of TECHTURN (1), a technologically oriented system for turned components. The SETUP module takes into account the geometrical data of the blank and the component, the technological requirements placed on the component such as surface roughness, concentricity and run-out, and the available work-holding devices for the machine on which the component is to be made. The system automatically determines the following parameters: (a) the work-holding method, that is the use of a chuck, or a chuck and centre or centres; (6) the number of setups required to complete the job; and (c) the clamping positions on the blank and component. In determining this, the system takes into consideration the different clamping devices available on the machine, and their characteristics. If more than one setup is essential, the system tries to balance the stiffnesses of the component in the different setups. This ensures that the stiffness of the component will have a minimum effect when the cutting conditions are calculated.

The system can deal with cylindrical blanks as well as castings and forgings, which, often, are of complex shape. To demonstrate the working of the SETUP module, several examples are included.
Repair of Composite Aircraft Parts: An Operator's Viewpoint
Authors: Armstrong K B
Published: February 2007

This paper discusses the problems of repair experienced by aircraft operators and some actual repairs are mentioned. The use of cold-setting adhesives is compared with the hot-setting pre-pregs recommended by the manufacturers.

A need is then shown for more mechanical and physical property data on both the original pre-preg resins and the cold-setting resins that may be used for repair when the provision of hot-curing is difficult.
Manufacturing Machinery in the Computer Era
Authors: Sweeney G
Published: February 2007

In order to remain competitive in demanding markets, industrial companies have to continue to reduce their dependencies on specialized machinery of relatively limited capabilities and introduce general-purpose machines and modules which can be reprogrammed centrally and/or locally.

A review of the type of work required, together with the responses of some manufacturing companies, academic establishments and governmental bodies to this challenge, are the subjects of the present article.
A System for the Efficient Management of the Design/Development Processes
Authors: Clarke R B , McKeag D
Published: February 2007

This paper presents a methodology for co-ordinating the requirements of policy, technology and marketing into one product design and development strategy. The methodology is based on a matrix structure, onto which is superimposed a flow diagram indicating the process of design and product development. Within the matrix structure, the flow diagram can be tailored to meet the requirements of any company. This model is used in co-operation with a policy management group to effectively discipline and control the complex task of fulfilling market needs with products meeting specifications, available on time and at the right price. The methodology has been implemented by the authors in industry through consultancy activities.
The National Quality Campaign: A Study of its Impact on Industry
Authors: Lascelles P M , Dale B G
Published: February 2007

This paper presents some findings, based on three studies funded by the Department of Trade and Industry, on the influence of the National Quality Campaign on British industry. The Campaign material has been relatively successful in reaching its prime target of senior management; the majority of respondents have found the material to be useful and believe that the Campaign has benefited their organization in terms of increased awareness of the importance of total quality management. It is also pointed out that people have high expectations of government in continuing to promote national awareness of quality management and disseminating quality-related information. The paper goes on to explore the possible future direction of the Campaign.
Flow in the Inlet Manifold of a Production Diesel Engine
Authors: Arcoumanis C , Whitelaw J H , Flamang P
Published: February 2007

The flow in the inlet manifold of a Ford direct injection diesel engine has been characterized by laser Doppler anemometry under motored conditions at engine speeds between 300 and 1100 r/min. Plexiglass windows have been inserted at three locations in adjacent manifold branches of the four-cylinder engine and back-scatter LDA was used to provide information about the ensemble-averaged and in-cycle axial and radial velocities at various spatial locations within the inlet channels during the engine cycle.
Identification of Bearing Dynamic Coefficients by Unbalance Response Measurements
Authors: Lee C-W , Hong S-W
Published: February 2007

An identification scheme for bearing dynamic characteristics by using unbalance response measurements is developed for rigid rotor systems supported by two anisotropic bearings. This scheme uniquely identifies the bearing dynamic coefficients, consisting of four damping and four stiffness coefficients, utilizing unbalance response measurements from four sensors at two locations for two different trial unbalance conditions. The fundamental assumption made in the proposed method is that the inertia properties of the rigid rotor are known. The procedure of identifying bearing dynamic coefficients by using the proposed method is presented and demonstrated through a numerical example.
An Adaptive Control Approach to the Ring Geometry Control for Radial-Axial Ring Rolling Processes
Authors: Choi HD , Cho H S
Published: February 2007

This paper considers the radial-axial ring rolling process control and treats the problem of controlling the pressure roll and conical roll motions which are critical to final dimensional accuracy of rolled products. Since the process dynamics reveals non-linear characteristics and parameter uncertainty, an adaptive controller design method is proposed for the pressure roll and conical roll motion control, taking into consideration the process dynamics variation. The effectiveness of the proposed controller has been verified by computer simulation. The simulation results show that the ring rolling process with this adaptive controller is insensitive to variation of process parameters and yields desirable dimensional accuracy of rolled ring products.
The Effects of Foot Trajectory on the Power Required to Swing a Mechanical Leg
Authors: McCloy D
Published: February 2007

The paper examines a two-degree-of-freedom serial-operated mechanical leg, driven by rotary actuators at hip and knee joints. When determining dynamic effects, three foot trajectories are compared: (a) ballistic, in which the foot is literally thrown from the end of the step to its start, (b) rectangular and (c) smoothed rectangular. In each case the conditions for minimum total energy are determined. In addition, when the trajectory is a smoothed rectangle, energies and powers for each actuator are calculated, and optimum conditions determined.
Twenty-First Century Truck Electronics—Today's Global Challenge
Authors: Aravosis G D
Published: February 2007

The main catalyst for use of state-of-the-art electronics in commercial trucks in the United States is the need to meet EPA emission standards for the 1990s. Important secondary catalysts are fuel economy, anti-lock brake systems and fleet/driver expectations. There are also myriad other forces related to safety, maintainability, servicing and communication which will be satisfied once electronic systems are installed in trucks.

The principal economic justification for incurring the cost of electronics at this time is to satisfy these more stringent gaseous emission and particulate regulatory standards. Using electronics, these standards can be met without producing a severe reduction in fuel economy while, as a by-product, interfacing with other truck components, such as brakes, transmissions, safety controls etc.

This paper will address the applications of electronics today for diesel engine controls as well as the applications of electronics in areas such as smart power switches, anti-jackknife controls, voice-recognition systems and other future system applications.

The exploding use of electronics in trucks will require solutions to many complex problems which are not unique to any one company, geographic area, country or technical society.
Statistical Relationships between Early Light Emission and Peak Pressure in a Spark Ignition Internal Combustion Engine
Authors: Belmont M R , Hancock M S , Buckingham D J
Published: February 2007

This paper reports on the correlations observed between ignition parameters and cycle-by-cycle variations in lean-burn petrol engines. The main concern was the statistical relationship between the light produced during the early part of the cycle just after spark ignition and the peak pressure achieved.
Training for Design for Manufacture
Authors: Donovan J R
Published: February 2007

This paper identifies how training for design for manufacture has needed to change dramatically to best serve the demands of a modern competitive business. It highlights the issues of organization for design and the use of teams to achieve cross-functional integration.

The style and content of the training is described to achieve the best use of people working as teams and to provide the knowledge required to operate the design process for competitive success. The structure of the design process is detailed and forms the structure for the training workshops to follow.
An Integrated Approach to Quality Engineering in Support of Design for Manufacture
Authors: Brown A D , Hale P R , Parnaby J
Published: February 2007

This paper discusses how customer satisfaction is achieved by the clear identification of all in-line customer requirements which are made visible and traceable throughout the product introduction process in a cross-functional team environment.