bluuebunny/crossref_metadata_2025 huggingface dataset:
Polymer Melt Rheological Property Measurement in a Novel Composite-Geometry Flow Rheometer
Authors: Humphries C A M , Parnaby J
Published: February 2007

A novel rheometer is described, in which extensional viscosity and elastic shear compliance are determined simultaneously from pressure measurements taken on steady state polymer melt flows through an open-ended die with successive, similarly shaped, converging and diverging zones. Equations incorporating practically realistic simplifying approximations are developed for the calculation of extensional viscosity and shear compliance from the measured pressure data. The construction of a prototype rheometer is described, and results from its operation are presented. Agreement between these results and published melt elasticity data for a low-density polyethylene material gives evidence to confirm the basic rheometric principle and flow analysis. The implications of pressure measurement errors are discussed. Assembly of the new composite-geometry rheometer in series with a conventional capillary viscometer would give in-line shear viscosity characterization simultaneously and facilitate on-line processing of pressure data from the converging and diverging flows by microcomputer to provide complete characterizations for practical use in polymer process machinery design. The work represents a significant advance on the basic empirical power law modelling process used for many years by practising engineers to represent shear viscosity phenomena as a basis for design. No other methodology is currently available to suit the engineer.
The Nature of Slip in High-Speed Axially Loaded Ball Bearings
Authors: Dominy J
Published: February 2007

This paper develops a simplified numerical technique for the analysis of heat generation and cage slip in high-speed axially loaded ball bearings. The model compares well with experimental results and has shown the characteristic slip behaviour associated with ball bearings. It has been possible to use the model to investigate the nature and causes of slip in lightly loaded ball bearings and it has been shown that the mechanism is primarily dependent upon the spin power, which falls rapidly as slip sets in. The characteristics of slip in ball bearings are shown to be quite different to those in roller bearings.
Forces in a Heavy-Duty Drive Chain during Articulation
Authors: Hollingworth N E , Hills D A
Published: February 2007

A rigid-body analysis is presented of the forces which occur in a chain bearing during articulation.

Coulomb frictional effects due to unlubricated contact are included, as these provide the energy source for deleterious wear processes and affect the force distribution. The analysis differentiates between the two types of chain bearing—open end leading or open end trailing—and the results show that the force characteristics in each are significantly different.

Experimental verification of the chain link tension is good.
Theoretical Efficiency of a Cranked Link Chain Drive
Authors: Hollingworth N E , Hills D A
Published: February 2007

In a previous paper (1), the contact forces in a chain bearing during articulation were established. The present note describes the application of these results to the theoretical evaluation of efficiency for a conventional chain transmission using cranked link (or offset) type chain.
Vibration of Hemi-Ellipsoidal Axisymmetric Domes Submerged in Water
Authors: Ross C T F , Johns T
Published: February 2007

Ten thin-walled domes, of hemi-ellipsoidal form, were vibrated in air and while partially and fully submerged in water. The domes varied in shape from oblate ones of aspect ratio (AR) 0.25 to prolate ones of aspect ratio 4.

The fundamental modal patterns for the oblate domes tended to be of axisymmetric form, while the fundamental modal patterns of the hemispherical and prolate domes tended to be of asymmetric or lobar form.

The theoretical analysis was carried out by the finite element method, where the motion of the shell structure was represented by three different types of element and the motion of the water was represented by a solid annular element.

Comparison between theory and experiment was found to be good.
A Comparison of Orthogonal Transforms in Their Application to Surface Texture Analysis
Authors: Mulvaney D J , Newland D E , Gill K F
Published: February 2007

The orthogonal transforms most commonly used in engineering applications are compared in their ability to characterize surface texture data. The results suggest that, for this application, the Fourier and cosine transforms are to be preferred because of their ability to model the data more precisely and because of their relatively rapid rates of convergence.
Round Sudden-Expansion Flows
Authors: Khezzar L , Whitelaw J H , Yianneskis M
Published: February 2007

This paper describes an experimental investigation of the water flows through one axisymmetric and two asymmetric round sudden expansions from a 48 mm to an 84 mm diameter pipe and eccentricities of the pipe axes of 0, 5 and 15 mm respectively. Flow visualization revealed the presence of vortex rings downstream of the plane of expansion for transitional Reynolds numbers (Re, based on the upstream pipe diameter and bulk flow velocity) and reattachment lengths were determined in the Reynolds number range 120–40 000 for all three cases. Detailed measurements of the three mean velocity components and corresponding fluctuations were obtained by laser anemometry for Re = 40000. Wall static pressure measurements are also presented.

The results show that asymmetry of the inlet geometry strongly influences the distribution of mean and turbulence quantities downstream of the expansion and results in three-dimensional reattachment. In all three flows, the mean flow was nearly uniform and the turbulence nearly homogeneous at distances of seven diameters of the large pipe downstream of the expansion. Higher levels of turbulence were found in the asymmetric ducts with maxima twice those in the axisymmetric duct.
Improving the Overall Efficiency of Trucks and Buses
Authors: Hahn H W
Published: February 2007

The paper reviews areas in which transport efficiency can be improved for heavy trucks, city buses and lightweight delivery vehicles. Areas considered include fuel consumption improvements by development of engine characteristics to suit specific operational requirements, the reduction of traction resistance, and the influence of the power-weight ratio on overall efficiency.

A method of calculating efficiency is described which includes topographic data, driving regimes and alternative mission cycles, which enables alternative configurations to be evaluated.

The paper concludes that powertrain components will have to be developed in future to accommodate a wider and better matched application while achieving improvements in reduced cost by greater use of standardized components.
Energy Audit on a Two-Litre Saloon Car Driving an Ece 15 Cycle from a Cold Start
Authors: Boam D J
Published: February 2007

In an effort to identify the aspects of vehicle operation which have most influence on fuel consumption during the ECE 15 driving cycle an energy audit was carried out on a two-litre saloon car driving such a cycle. The most interesting results to emerge were that, in the first cycle, 12 per cent of the fuel passed through the engine either partially or completely unburnt, 8 per cent emerged as useful work, and 60 per cent was used to warm up the engine and transmission, while 10 per cent was rejected in the exhaust gas as heat.
The Relationship between Twist Axis and Effective Torsional Stiffness of a Motorcycle Frame
Authors: Raines M , Thorpe T E
Published: February 2007

The design of a motorcycle frame has an important influence upon the machine's weave and flutter oscillation characteristics. This paper deals particularly with the torsional stiffness of the frame and it underlines the importance of the position of the axis about which the frame twists.

This concept of a twist axis is introduced by reference to a simple parallel tube structure. It is demonstrated that because the twist axis moves, the torsional stiffness of a structure may reduce as individual members are stiffened. The position of the twist axis of a motorcycle frame is determined by finite element techniques and it is shown that an attempt, without due consideration of the twist axis, to improve its torsional stiffness, in fact has the opposite effect.
XPT Two Years On
Authors: Sismey B G , Pugh R , Tate M R
Published: February 2007

The Express Passenger Train (XPT) has been introduced by the State Rail Authority of New South Wales on selected country services. This paper describes the introduction of the train for passenger service, the performance achieved and the maintenance experience after two years of operation.
Parametric Analysis of Tracked Vehicle Performance Using an Advanced Computer Simulation Model
Authors: Wong J Y , Preston-Thomas J
Published: February 2007

The major features of a computer simulation model, NTVPM-85, designed for parametric analysis of tracked vehicle performance are presented. The application of the model to the evaluation of the effects on tractive performance of vehicle design and operational parameters and terrain characteristics is demonstrated. The model can be an extremely useful aid in the evaluation of competing designs and in the examination of the effects on performance of design modifications and operational environments.
Modelling Vibration Transmission Through Coupled Vehicle Sub-Systems Using Mobility Matrices
Authors: Hemingway N G
Published: February 2007

This paper indicates how vibration responses of a vehicle body produced by inputs at the rear wheels were modelled using a mobility matrix coupling method. The model simulates the multiple coupling of the sub-assemblies comprising the rear axle, rear suspension and vehicle body in the lower audio-frequency range. Such a model is useful when investigating the transmission paths along which vibrations travel into the vehicle body, subsequently generating internal noise.
Application of State of the Art Simulation Technology to Railway Driver Training
Authors: Grant L G
Published: February 2007

Recent advances in computer and visual system design have made locomotive driver training by simulator a viable proposition. This paper discusses the design objectives of such a simulator and describes recent experience in this area.
AV-SB/GR Mk 5 Airframe Composite Applications
Authors: Riley B L
Published: February 2007

This paper describes the composite applications on the AV-8B/GR Mk 5 Harrier II airfame. Twenty-five per cent of the airframe weight is composite materials resulting in a weight saving of 525 lb per aircraft. Topics covered in this paper include the composite wing, forward fuselage and horizontal tail designs, the development test programmes, design philosophy, interpretation and evaluation of test results, impact damage, ballistic damage, lightning, repairs, and manufacturing defects.
A Steering Bogie for the British Rail Class 37 Locomotive
Authors: Pennington K W , Harwood N A , Peat D M
Published: February 2007

This paper describes the theoretical and practical design studies undertaken to improve the curving perfornrance of the British Rail Class 37 Co–Co locomotive to reduce expensive wheel and rail wear on the West Highland Line. Observatiomfrom preliminary performance trials with a locomotivejitted with prototype steering bogies are also discussed. It is shown how a traditional design can be improved through current theoretical understanding to provide a practical solution to an operating problem.
The Design of an Engine-Flywheel Hybrid Drive System for a Passenger Car
Authors: Schilke N A , DeHart A O , Hewko L O , Matthews C C , Pozniak D J , Rohde S M
Published: February 2007

The quest to improve the fuel economy of General Motors passenger cars has led to the investigation of an engine-flywheel hybrid powertrain at the GM Research Laboratories (GMR). An engine-flywheel system was designed for a compact car and its performance was predicted analytically. The sytem was estimated to achieve an improvement in EPA composite fuel economy of 13 per cent ooer a 1984 production compact car. This margin of improvement was judged insuficient to justify the complex drivetrain, and, therefore, a prototype system was not built. However, the current potential of engine-flywheel hybrids for GM passenger car applications has been defined, and the technology areas requiring additional research attention have been identified.
The Development and Performance of an Ambulance Stretcher Suspension
Authors: Leyshon D R , Stammers C W
Published: February 2007

The deterioration of the medical condition of stretchered patients during ambulance transport is discussed. The dominant vibration is generally low frequency (below 10 Hz) and in the vertical direction. Assessment of the sensitivity of supine patients to front-to-back vibration is referred to.

Methods of alleviating the vibration experienced by stretchered patients are discussed and particular types of stretcher suspension described.

This suspension has a constant natural frequency of vertical oscillations over a wide range of patient mass. A stretcher ride height (above the ambulance floor) independent of patient mass is achieved.

The stretcher suspension was tested over four types o surface (one ofl-highway), using a commercial vehicle having a chassis similar to that of a commonly used ambulance. Vibration of the vehicle floor and of the stretcher in both the vertical and the pitch senses was measured using accelerometers.

Transmissibility of the stretcher suspension, the stretcher frame and the stretcher mattress was obtained. The vertical vibration level (averaged over the four types of surface) experienced by the patient is compared with vibration tolerance levels for supine patients. Vibration inputs are closest in magnitude to the vibration exposure limit in the range 1.5–4 Hz. The transmissibility of the suspension in this range is between −7 and −9 dB.

Subjective evaluation of the suspension has been favourable.
Analysis and Performance of a Geared Permanent Magnet D.C. Starter Motor
Authors: Mhango L M C
Published: February 2007

The geared permanent magnet d.c. starter motor has several significant advantages over the wound-field starter, some of which are discussed. The acceleration performance and the cold cranking are shown to depend on both the battery internal resistance and the motor armature resistance. Typical motor characteristics and principles of design optimization are discussed, and it is shown that a motor of reduced weight and high efficiency is achieved compared with comparative conventional machines.
The New Four-Wheel Anti-Lock Generation: A Compact Anti-Lock and Booster Aggregate and an Advanced Electronic Safety Concept
Authors: Bleckmann H-W , Weise L
Published: February 2007

An overview is given on hydraulic anti-lock systems with direrent pedal characteristics, power supply concepts, and physical configurations suitable for ‘add-on’ installation or functional integration. The integrated Teves anti-skid system is presented with special attention to a three-circuit configuration including ‘dynamic’ brake circuits. Different safety levels of electronic concepts compared to the advanced Teves approach, and the application of microprocessors are discussed.
The Use of Reliability Techniques on Traction and Rolling Stock
Authors: Puntis R , Walley D M
Published: February 2007

Traditionally British Rail has used experience and sound engineering practice to ensure reliable traction and rolling stock. In-service reliability has been measured in terms of frequency of train delays in traffic. Availability is measured in terms of the number of vehicles available for service at a fixed time each day. Service problems are reported to the design authority at periodic service problem meetings.

Modern traction and rolling stock specifications call for higher petformance to be obtained within tighter cost, size and weight constraints. To meet these demanding specifications, new system designs of increasing complexity have to be adopted. This has resulted in an increased engineering risk that the performance specifications will not be met.

To ensure that reliability and availability remain acceptable, it is becoming increasingly necessary to use reliability modelling and assessment techniques. These are used from initial concept, throughout the design phase, and during the operational life of the equipment.

This paper outlines some of the basic techniques which are available to assist in the solution of today's service problems and the design of tomorrow's vehicles. The application of these techniques will be illustrated by examples.
Railways—Do or Die
Authors: Sephton B G
Published: February 2007

The 1986 Railway Division Chairman outlines the problems facing the railways because of the decline in passenger and freight traffic over the past thirty years, and expresses his views on the contributions that engineers can make towards a strategy for recovery of the railways' market share. He gives details of how costs may be reduced in design, construction and maintenance of track, locomotives and rolling stock and how service to the customer may be improved.
The Design and Development of a New Luxury Sector Automobile
Authors: Randle J N
Published: February 2007

This paper describes the programme of design and development undertaken during the production of the a luxury automobile, the Jaguar XJ40.
Development of An Air Mass Flow Sensing Microprocessor-Based Fuelling and Ignition System
Authors: Baxendale A E
Published: February 2007

The philosophy for the choice of engine management systems for the Jaguar XJ40 is discussed, and certain features developed for the 3.6 litre engine are described in detail.
TD Tyres for Jaguar
Authors: Day P S , Holmes T , Major D J
Published: February 2007

This paper gives a technical description of the Dunlop 220/65VR390 TD SP Sport D7 safety tyre and wheel and a summary of the testing methods used in its development for the Jaguar XJ40.
A Dynamic Modelling Technique for the XJ40 Body Structure Design
Authors: Brown A M , Dunn J W
Published: February 2007

This paper combines the principles of quantitative structural dynamics standards with a theoretical modelling analysis, and applies it to the Jaguar XJ40 body structure design. This work has resulted in high levels of vehicle refinement in terms of noise and vibration transmitted to the occupant in the complete car.
The design and assessment of the XJ'40 instruments and controls
Authors: Holtum C
Published: February 2007

The process of designing new vehicle instruments and controls is discussed together with the ergonomic work undertaken to ensure the successful integration of these new features with existing systems in the Jaguar XJ40.
The Utilization of Fatigue life Prediction Techniques in Support of a Major Vehicle Project
Authors: Tivey C J
Published: February 2007

In this paper the techniques of fatigue life predictions are discussed along with decision paths that were necessary to enable design and development of the Jaguar XJ40 front suspension to take place.
Developments in Methods of Inelastic Piping Analysis
Authors: Boyle J T , Spence J
Published: February 2007

It is the aim of this paper to survey recent developments in the methods of inelastic piping system analysis. Particular attention is paid to simplified methods which avoid costly finite element analysis. Included is a survey of available computer codes, benchmarks and comparative studies together with a discussion of simple screening rules based on elastic analyses alone.
Gas-Fed Reciprocating Engine Development
Authors: Gillespie D A
Published: February 2007

In recent years intensive development of reciprocating internal combustion engines has led to progressively higher ratings with improved thermal efficiency and an ability to operate successfully on poorer quality fuels. Rising fuel costs have also led to an increasing interest in alternative fuels, and this in turn has promoted the design and development of engines capable of burning a variety of gases. The paper describes the design performance features and recent development achievements of a range of medium-speed gas-fed reciprocating engines with a capability to burn a range of gaseous fuels from natural gas down to synthetic or by-product gases with low calorific values of 4.85 MJ/m3(n).
Process Integration—A Structured Approach to Operating Cost Reduction
Authors: Hill J C
Published: February 2007

The technology of process integration is gaining wide acceptance within the process industries as an essential tool in the design of energy efficient processes. Within ICI plc initial research into the fundamental theory of the technology was reinforced by the establishment of applications teams comprising experienced process engineers who are expert in the technology. This method of utilizing the technology has created a dialogue between the research and applications teams over the past five years and has resulted in the development of a range of techniques which, while based on the initial theoretical research, are practical design aids applicable to a wide variety of processes.

This paper indicates the benefits that can be gained from the application of the full range of process integration techniques and highlights some of the lessons that have been learnt, by companies new to the technology, in recent studies. It draws on experience gained within ICI plc and in studies carried out for a variety of major industrial companies by the Energy and Process Integration Service (EPI) which is a joint ICI-Harwell venture offering energy efficiency consultancy.

The understanding of processes offered by process integration techniques generates insights which enable experienced personnel to identify ways in which the process itself can be modified to further improve its energy efficiency. The latest developments in the technology have produced a structured approach to the design of processes the aim of which is to reduce the total variable cost of operation.
Review of Parameters Influencing Hydraulic Forces on Centrifugal Impellers
Authors: Guelich J , Jud W , Hughes S F
Published: February 2007

Both radial and axial hydraulic forces act on the impeller of a centrifugal pump. The radial forces are due to three different mechanisms: (a) radial thrust due to non-uniform pressure distribution around the impeller, (b) labyrinth forces and (c) impeller-diffuser interaction forces. The nature, size and origin of these forces are discussed. Steady radial thrust depends on the specific speed of the pump, type of casing (single or double volute, diffuser), geometric parameters and operation conditions including cavitation. The impact of these factors on radial loads is demonstrated and quantitative data are presented. Four different methods for radial thrust measurements are presented.

Axial thrust on pump impellers is extremely sensitive to tolerances and to the labyrinth flowrate. Two methods for predicting axial thrust are discussed and predictions are compared to measurements on a multi-stage boiler feed pump. A number of parameters influencing axial thrust are treated.
Approximate Analyses of Feed and District Heating Cycles for Steam Combined Heat and Power Plant
Authors: Horlock J H
Published: February 2007

An assumption for turbine expansion lines originally made by Salisbury and Haywood (that the difference between local steam enthalpy and the enthalpy of saturated water at the same pressure is constant throughout the expansion) is used in approximate analyses of steam combined heat and power plant. Thermal efficiencies and energy utilization factors are derived for a number of cycles with steam extraction for feed heating and for district heating. Calculations of these two parameters are presented for relatively low pressure cycles.
Economic Performance Optimization of a Combined Heat and Power Station
Authors: Foster D
Published: February 2007

This paper describes an application of non-linear numerical methods to the on-line steady state optimization of a combined heat and power station.
In-Reactor Inspections and Repairs at Oldbury Power Station
Authors: Fairweather E J
Published: February 2007

The paper identifies the need for in-reactor maintenance, and outlines the development and use of remote handling techniques and equipment at Oldbury power station to provide assurance of continued structural integrity.
Gas Circulator Repairs
Authors: Gould A W
Published: February 2007

The failure in May 1983 of the thrust bearing of a gas circulator on one of the Magnox gas-cooled reactors at Oldbury-on-Severn power station gave rise to a series of problems not previously experienced in the maintenance and repair of circulators. Investigations to discover the extent of damage revealed defects that were traced back to original manufacturing standards and testing procedures. The thrust bearing failure prompted a more critical examination of maintenance dismantling/rebuild procedures and standards, leading to changes in the organization and quality control of circulator maintenance activities. A longer-term programme to improve the build standards of all the eight gas circulators has been adopted.
Determination of the Initial Gaps between Flat Flanges without Gaskets
Authors: Lewis L V , Fessler H , Hyde T H
Published: February 2007

This paper describes a method of finding the size and shape of the gaps which exist between the faces of an assembled but unloaded fiat-faced, metal-to-metal flange joint. The low-pressure leakage of 26 such assemblies has been measured experimentally, and pressure tappings have been used to record the pressure distribution under the contact faces of some of the flanges. Formulae are derived for the conversion from experimental data to gap size and shape.

The method gives a very sensitive measure of gap height because of the cubic nature of the conversion formulae. Gap heights in the range 4–30 μm have been found. It is shown by finite element calculations that deflections due to boll loading of a perfectly flat flange are much smaller than the observed initial gaps.
Engineering Education for Fitness for Purpose
Authors: Crossland B
Published: February 2007

The President reviews his career in industry and higher education, and he refers briefly to his research interests in high-pressure engineering and explosive welding. He states his belief in the indivisibility of education and training and outlines the desirable objectives of education and training, which he considers should be directed at ‘design for profitable manufacture’. Finally, he notes the continuing importance of developing ever closer co-operation between industry and higher education.
On the Dynamics and Control of Robotic Manipulators with an Automatic Balancing Mechanism
Authors: Chung W K , Cho H S
Published: February 2007

Non-linear characteristics and uncertainty in manipulator dynamics caused by payload effects are major hurdles in controller design. To overcome such hurdles the authors have introduced an automatic balancing concept which has been proved to reduce the non-linear complexity in manipulator dynamics as well as to remove gravity loading. This paper examines the characteristic features of balanced manipulator dynamics in more detail and presents an efficient control algorithm suitable for the dynamics. Since the dynamics of a balanced manipulator are characterized by partially configuration-independent inertial properties, the present algorithm adopts two different control concepts ‘the computed torque control’ for the joint having coupled, configuration-dependent inertia and ‘an optimal constant feedback control’ for the joints having configuration-independent inertia. To evaluate the proposed control algorithm, simulation studies were made over a wide range of manipulator speeds and payloads. Based upon the simulation results, the efficiency of the controller is discussed in detail.
Product Selection and Investment Appraisal for Flexible Assembly
Authors: Williams D F , El-Tamimi A M , Suliman S M A
Published: February 2007

An approach has been developed for the solution of the flexible assembly product selection problem. Identifying suitable products for the system is achieved by a set of product selection criteria which is based on the technological adaptability and financial requirements of competing products. The method developed enhances early design stages by providing the most appropriate candidate product(s) and enabling an efficient system to be selected.
Use of the Fokker Bond Tester on Joints with Varying Adhesive Thickness
Authors: Guyott C C H , Cawley P , Adams R D
Published: February 2007

The operation of the Fokker bond tester has been investigated. The instrument monitors one of the natural frequencies of the system comprising a piezoelectric crystal coupled to the joint under test. The resonant frequencies of two different sizes of transducer coupled to both plain plates and adhesive joints have been investigated both theoretically and experimentally, the measured values being in line with the predictions. It has been concluded that the method is satisfactory for the location of disbonds in a multi-layer construction but that it cannot distinguish between adhesive modulus and adhesive layer thickness. Both of these parameters affect the adhesive stiffness and hence the measured resonant frequencies. However, they have different effects on the cohesive strength of the adhesive so unless independent measurements of, for example, thickness are made, erroneous strength predictions may be obtained. Also, the measured frequencies are independent of adhesive stiffness over a wide range of typical stiffnesses, so changes in adhesive properties will not be measured in these cases.
High Technology in Shipbuilding
Authors: Milne P A
Published: February 2007

Following a review of market developments and their dramatic effects on shipbuilders, the paper makes a case for a continuing shipbuilding industry in Europe, and reviews the investment in high technology equipment in merchant shipyards. The introduction of computer-based systems in the industry and the extensive use of CAD/CAM in shipyards are described. The use and potential of industrial robots and lasers are covered. Advances in engine construction and ship production resulting in shorter delivery times and reduced costs are illustrated. Engine selection by computer program is described and the paper concludes with a view on future changes in merchant shipbuilding.
Hovercraft Skirt Design and Manufacture
Authors: Wheeler R L , Key A N
Published: February 2007

Skirts are the inflated structure which extend around and beneath a hovercraft that allow the craft to operate in rough seas and over uneven ground. The early skirts were designed on the basis of model testing and practical experience, but as the size of craft increased and improved performance was required it became evident that a more sophisticated approach was needed. This was carried out by developing computer programs to design the sectional shapes, investigate the quasi-static behaviour and derive the flat pat tern shapes from which the skirt is made. The responsive skirts fitted to large cross-Channel hovercraft, the Super 4, and the latest coastal craft, the AP 1-88/100 were developed using these techniques.

Investigations into the cutting of sheets of non-metallic materials by a high-pressure water jet showed that this was ideal for the nylon woven fabric coated with either natural rubber or neoprene from which skirts are made. A cutting table with a NC tape-fed controller has been developed with a jet of 0.15 mm (0.006 in) diameter operating at 379 MPa (55000 lbf/in2). All the processes of producing a skirt, design, detailing with CADAM, part programming and cutting out are now integrated via computer links giving significant savings of time and costs.
Computer Integrated Manufacturing: A Case Study in the Development of Thermoplastic Seals
Authors: Clark V L , Peppiatt N A , Steel J , Smith S
Published: February 2007

This paper reviews a project which opened up a multi-million pound market to Hallite Seals for a new and innovative range of thermoplastic seals and at the same time drastically reduced the cost of existing products. The project duration was kept to one year by taking advantage of new technologies wherever possible. The project not only achieved the marketing objectives within the planned time-scales, it also provided a payback on capital expenditure of over £330 000 in less than 12 months. Severe customer service problems on existing products were eliminated and the value of stocks and work-in-progress was significantly reduced.
A Study on the Three-Dimensional Analysis of the Transient Temperature Distribution in Gas Tungsten Arc Welding
Authors: Na S-J , Lee S-Y
Published: February 2007

The transient temperature distribution in the gas tungsten arc (GTA) welding process was analysed by employing a three-dimensional finite element model. In the formulation, the solution domain which moves with the welding heat source was introduced to minimize the number of elements, and consequently the computation time of the three-dimensional program. Since the moving solution domain is small compared with the real weld structure, there are two kinds of boundaries, namely, solid metal-atmosphere boundary and solid metalsolid metal boundary. The heat loss through the solid metal-solid metal boundary was considered through a conduction heat flow and the heat flow through the solid metal-atmosphere boundary through a convection heat flow. As the solution domain moves with the progress of welding, new boundary conditions and new elements were generated in front of the heat source, while some elements disappeared in the rear of it. The initial temperature distribution of the new elements was determined by considering the continuous temperature gradient. To verify the numerical analysis, GTA welding experiments were performed on a medium-carbon steel and the isothermal lines examined. The transient isothermal lines of fusion and heat affected zone boundaries obtained numerically and experimentally were in good agreement. Thus, with the small moving solution domain the change of the fusion zone shape in long welds can be easily analysed, so that, for example, the transient melting characteristics at the start of welding in automatic welding can be effectively simulated for the process optimization.
An Adaptively Controlled Electrohydraulic Servo-Mechanism: Part 1: Adaptive Controller Design
Authors: Edge K A , Figueredo K R A
Published: February 2007

A systematic model reference adaptive control design scheme is presented. The control scheme is developed and analysed within the framework of a sampled data system with a parameter adaptive algorithm designed on the basis of hyper stability theory. A number of supervisory functions are used to supplement the basic adaptive control system in order to enhance robust controller action.
Product Development Problems in 1987—A Diagnosis
Authors: Ashton E W S
Published: February 2007

A set of ‘rules’ is suggested to cover the present limitations imposed on product development in public companies by the requirement of institutional investors for regularly increasing profits.
Maintenance—Some Legal Aspects
Authors: Niven B
Published: February 2007

‘Maintenance’ can mean different things to different people. Where the law is concerned in the use of plant and machinery, the courts may interpret ‘maintenance’ and its cognates in ways which need to be understood by engineers.

Some key legal cases and statutes on the question of maintenance are reviewed and their effects and implications discussed.
Getting the Best Out of Your Workforce
Authors: Carter B A
Published: February 2007

It has been found that output has increased as a result of increased interest in the workers and is not necessarily the result of improved working conditions. To this end it is important to develop a management approach that will improve a company's overall effectiveness. A common goal for all the employees must be given where the part each individual must play is detailed.

This paper outlines various approaches that can be used to motivate employees. If they are implemented British industry may be able to raise itself from the bottom of the European industrial league.
An Electrochemical Machining Method for Removal of Samples and Defective Zones in Metal Pipes, Vessels and Structures
Authors: Clifton D , Midgley J W , McGeough J A
Published: February 2007

An electrochemical machining method for removing samples and defective zones in engineering structures has been investigated. It has been shown that samples can be removed in a controllable way and as the surface produced at the removal site is smooth and metallurgically undamaged the workpiece is suitable for subsequent welding repair without further preparation. As the method is forceless it would be simple to automate.
New Business Selection for a Subcontracting Company—A Case Study
Authors: Woodhouse J
Published: February 2007

A case study involving an engineering subcontractor has been used to illustrate a methodical evolutionary approach and an ideas list approach for identifying new business. The subcontractor company was in a state of chaos, rendering it incapable of acting upon new ideas. This may be a common failing of subcontractors. As insufficient data were available to operate the models, synthetic data have been used to provide illustration. A methodical approach is preferred. It involves systematic monitoring of manufacturing, market and technological trends. Such measurements must be a part of the change management process. Evidence suggests that this works in other environments.
Formulation and Solution of a Set of Sequencing Problems for Flexible Manufacturing Systems
Authors: Wilson J M
Published: February 2007

This paper describes the philosophy behind the construction of a computer technique which has been used to formulate and solve a set of sequencing problems for efficient use of a flexible manufacturing system (FMS). These problems are formulated as integer programming problems and are solved using commercially available software. Problems can be solved in reasonable computational time and the solutions can then be used to set up operating conditions for an FMS.
An Anisotropic Model for Inclined Surface Solar Irradiation
Authors: Saluja G S , Muneer T
Published: February 2007

The validity of various models for predicting irradiance on inclined surfaces was investigated by employing one-year measured hourly irradiation data on horizontal and vertical surfaces for Easthampstead (51.4°N, 0.8°W) in the United Kingdom. This led to the development of an improved anisotropic model that distinguished between shaded and sunlit surfaces and between overcast and non-overcast conditions of the sunlit surfaces. The accuracy of the proposed model was compared with those of Klucher and Hay and the model was further tested against short-term measured data for four widely separated locations in the United Kingdom.
Elastohydrodynamic Lubrication of Circumferentially Finished Rollers having Sinusoidal Roughness
Authors: Karami G , Evans H P , Snidle R W
Published: February 2007

The paper describes an isothermal elastohydrodynamic lubrication analysis of rollers having circumferential sinusoidal roughness. Theoretical results are shown which demonstrate the influence of roughness amplitude on the distribution of hydrodynamic pressure and film thickness at constant load and constant roughness wavelength. At a large roughness amplitude the hydrodynamic pressure in the valleys between asperity contacts is insignificant and each asperity contact behaves as an ‘isolated’ elastohydrodynamic point contact. As the roughness is reduced, however, the valley pressures build up, the pressure becomes more uniformly distributed in the axial direction and the minimum film thickness increases.
Fluid Mechanics of Internal Combustion Engines—a Review
Authors: Arcoumanis C , Whitelaw J H
Published: February 2007

The paper reviews current knowledge of the flow processes within the cylinders of reciprocating engines and examines experimental and calculation techniques used to determine them. Topics requiring further research are identified and discussed.
Attitude control of a spacecraft using an extended self-organizing fuzzy logic controller
Authors: Daley S , Gill K F
Published: February 2007

A simple method for extending the range of sensitivity of the self-organizing fuzzy logic controller (SOC) is proposed. The performance of the resulting controller is studied through its application to the attitude control of a flexible satellite. It is found that the extended SOC can provide excellent control and also possesses a high degree of robustness.
A Review of Developments in the Acid Hydrolysis of Cellulosic Wastes
Authors: Anderson J , Porteous A
Published: February 2007

The acid hydrolysis of cellulosic wastes has attracted the attention of many research workers around the world, especially in the last decade. This high temperature and pressure process results in the production of sugars which may be fermented to ethanol. By virtue of their cellulosic content, agricultural, industrial and municipal solid wastes may all be processed by acid hydrolysis with an end result of waste disposal and recycling/recovery of important energy sources.

The complete process of the conversion of a cellulosic waste through to the end product and by-product utilization has to give due consideration to likely technologies. Some essential problems that have to be tackled are raw material storage, availability and preparation, the optimum acid hydrolysis and fermentation conditions and product separation methods.

This paper is a review of the research that is taking place not only in the field of acid hydrolysis but also in the types of waste used, the concentration of the product sugars, the optimization of the fermentation conditions and the use of low-energy alcohol recovery methods to replace conventional distillation. Most research is at bench scale level with some pilot plants being reported. Also included is the authors' current work using a continuous reactor for the hydrolysis of newsprint.
Plastic Buckling of Imperfect Hemispherical Shells Subjected to External Pressure
Authors: Galletly G D , Blachut J , Kruzelecki J
Published: February 2007

Plastic buckling/collapse pressures for externally pressurized imperfect hemispherical shells were calculated for several values of the yield point ( syp), the radius–thickness ratio ( R/t) and the amplitude of the initial imperfection at the pole (δ0). The well-known elastic–plastic shell buckling program BOSOR 5 was used in the calculations and two axisymmetric initial imperfection shapes were studied, viz. a localized increased-radius type and a Legendre polynomial.

The numerical collapse pressures ( pc) for both types of imperfection were normalized and plotted versus λ ( a parameter proportional to[Formula: see text]. Approximate algebraic equations were then derived which give pc/ pyp as a function of λ and δ0/t. The values of pc given by these equations agree well with the computer results.

Using the maximum values of the geometric shape deviations allowed by some national Codes, the corresponding theoretical buckling strengths were calculated. These were then compared with an approximate lower bound of test results obtained on externally pressurized spherical shells. The agreement between the two curves was not very good for BS 5500 but was fair for the DnV rules. The agreement with BS 5500 can be improved by increasing simp, the arc length over which the initial imperfections are measured.

The foregoing lower bound of test results on externally pressurized spherical shells can also be obtained, approximately, using increased-radius and Legendre polynomial imperfections in which the ratio Rimp/ R is not restricted. The magnitude of the initial imperfection required for approximate agreement between the experimental and theoretical results was δ0/t ∼ 0.5. This seems a reasonable value. However, more study of this aspect of the problem is required in both the elastic and plastic buckling regions. The limitation of Rimp/ R ≥ 1.3 imposed by some Codes should also be reviewed, particularly in the plastic regime.
Spool Hydraulic Stiffness and Flow Force Effects in Electrohydraulic Servo-Valves
Authors: Arafa H A , Rizk M
Published: February 2007

This paper deals with an analytical and experimental assessment of the flow force effects on electrohydraulic servo-valve steady state characteristics. The system mathematical model is derived, and special consideration is given to non-linearity of the feedback wire stiffness and magnetic saturation of the armature. The ‘spool hydraulic stiffness’ is defined and expressed in terms of the servo-valve parameters and supply pressure to allow clear interpretation of the nature of flow force effects. Experimental results of spool displacement decrement due to flow force versus net displacement are in good agreement with the predicted performance in a wide range of input current up to almost full magnetic saturation. The results provide evidence, on an alternative basis, of the non-linear feedback behaviour. Correlation is also made between flow force and limits of stable operation, and an expression is derived for the maximum allowable supply pressure.
Allowing for Nose Radius Effects in Predicting the Chip Flow Direction and Cutting Forces in Bar Turning
Authors: Young H T , Mathew P , Oxley P L B
Published: February 2007

A model is presented for predicting the chip flow direction and cutting forces for bar turning with nose radius tools. A comparison which is made of predicted and experimental results shows excellent agreement.
The Measurement of Wear Damage
Authors: Chetwynd D G , McKee F A , Wride C H
Published: February 2007

The good qualitative understanding of the processes of, for example, fretting wear which now exists has not led to good quantitative descriptions of predictive value. One reason for this has been the very high cost, or complete non-availability, of measurement techniques having the precision necessary to characterize the damage, especially during the early stages of wear. Weight loss has been, and remains, the major method, although profilometry-based mapping has also been tried. Here these two approaches are critically compared in terms of potential precision and information capability. Other profilometry methods which reduce costs by relaxing the need for relocation and full mapping while maintaining a reasonably high information content are proposed and examined practically. It is concluded that for routine work weighing remains the most cost effective method but that the simpler profile-based assessments have better precision and are quite practicable. Their use is particularly relevant to the early stages of wear.
Transmission Line Modelling of Shaft System Dynamics
Authors: Partridge G J , Christopoulos C , Johns P B
Published: February 2007

The transmission line modelling (t.l.m.) method is well established as a numerical routine for the solution of electromagnetic wave problems and electrical lumped networks. In this paper the method is adapted for the solution of dynamic mechanical systems.

The method provides discrete models suitable for manipulation by digital computer and straightforward modelling of non-linearities. A complete modelling example of a bearing with non-linear friction characteristics is presented.
Parameters for Characterizing the Surface Topography of Engineering Components
Authors: Sherrington I , Smith E H
Published: February 2007

Profile measurements of the surface topography of engineering components are often used in attempts to assess the functional suitability of surfaces. This paper reviews the definitions and properties of a large number of parameters which are used to characterize measurements of this type.