bluuebunny/crossref_metadata_2025 huggingface dataset:
Quality of the Surface Finish of the Head of the Femoral Component and the Wear Rate of the Socket in Long-Term Results of the Charnley Low-Friction Arthroplasty
Authors: Wroblewski B M , McCullagh P J , Siney P D
Published: February 2007

Four Charnley femoral stems, removed on average 20 years after implantation, were examined for the quality of surface finish of the head. The average roughness was 0.031 μm (range 0.008–0.102 μm) as compared with 0.019 μm (range 0.008–0.031 μm) for the current production models and 0.05 μm as recommended by the British Standard and the International Standards Organization.

The average socket penetration rate was 0.022 mm/year and there was no radiological or operative evidence of socket loosening. The findings emphasize the importance of achieving and maintaining good surface finish of the head of the femoral component. A suggestion is also made that the orientation of the asperities may be important.
A Five-Station Hip Joint Simulator for Wear Rate Studies
Authors: Saikko V , Paavolainen P , Kleimola M , Slätis P
Published: February 2007

The aim of the work has been the development of a hip joint simulator for comparative wear rate studies of long duration. A five-station apparatus has been designed, constructed and tested. Five total hip joints can be tested at the same time in identical conditions. The flexion-extension motion and the superior-inferior component of the joint contact force are incorporated. The motion is electromechanical and the loading pneumatic. The angle and load waveforms are fixed and simulate level walking. For accurate wear measurements each station employs a control prosthesis. The conditions of the control prosthesis in regard to loading, exposure to lubricant and environment temperature (37 ± 1°C) are identical to those of the test prosthesis. The acetabular cups can be readily removed for periodic wear measurements and reassembled in exactly the original position. Extensive tests have shown that the simulator is a practical and reliable instrument in the wear rate studies of various designs of total hip joint.
A Simulator Study of Friction in Total Replacement Hip Joints
Authors: Saikko V
Published: February 2007

Frictional behaviour of 22 different femoral head-acetabular cup combinations was studied on a new servo-hydraulic microcomputer-controlled hip joint simulator using various flexion-extension angle and superior-inferior load set value waveforms and using distilled water at 37 ± 1°C as lubricant. Six different head materials were included in the study, whereas all cups were ultra-high molecular weight polyethylene (UHMWPE). Most head-cup combinations studied are commercially available. No distinctly superior joint design can he pointed out, but the frictional behaviour of alumina ceramic against UHMWPE proved overall most favourable ( μmin was 0.02), whereas that of non-ion-implanted titanium alloy Ti-6Al-4V against UHMWPE proved strikingly poor ( μmax was 0.15). The lowest frictional torque was in 22 mm joints, but frictional torque did not always increase straightforwardly with increasing diameter of the femoral head. The measurements form an extensive comparison between a wide variety of head-cup combinations. The simulator is apparently a useful instrument in the study of frictional behaviour of new designs, materials, surface treatments and coatings that are frequently introduced.
Non-Linear Finite Element Analysis of Formation and Treatment of Intervertebral Disc Herniae
Authors: Dietrich M , Kędzior K , Wittek A , Zagrajek T
Published: February 2007

A biomechanical model of the spine motion segment L2/L3 consisting of the truncated vertebrae, endplates, intervertebral disc and pieces of anterior and posterior longitudinal ligaments has been used for a computer simulation study. A non-linear finite element analysis has shown that small loads compressing the spine, not greater than those occurring in everyday life, cause loss of stability of an intervertebral disc, resulting in lateral dislocation of its nucleus pulposus. This could be a potential cause of discopathy. The model indicates that conservative therapy of herniated disc by the traction method may result in retraction of hernia by about 40 per cent.
Finite Element Stress and Strain Analysis of the Bone Surrounding a Dental Implant: Effect of Variations in Bone Modulus
Authors: Clift S E , Fisher J , Watson C J
Published: February 2007

The long-term clinical performance of a dental implant is dependent upon the preservation of good quality bone surrounding the implant and a sound interface between the bone and the biomaterial. Good quality bone is itself dependent upon the appropriate level of bone remodelling necessary to maintain the bone density and the avoidance of bone microfracture and failure. Both processes are governed by the stress and strain distribution zn the hone. In this study, a dental implant which had the same geometry as the Branemark system, but with a bioactive surface coating added to produce a direct bond to the bone, was analysed. Ajinite element stress and strain analysis has been carried out for a range of bone density distributions under axial and lateral loading. The predictions indicated that there was no evidence of strain shielding around the neck of the implant. With lateral loading, high values of von Mises stresses (18 MPa) were predicted around the neck of the implant. A reduction in the elastic modulus of the bone around the neck of the implant by a factor of 16 only produced a twofold reduction in the peak stress. This resulted in stress levels capable of inducing fatigue failure in this much weaker bone. This analysis has demonstrated that it is extremely important to have good guality dense bone around the neck of the implant to withstand the predicted peak stresses of betweeen 9 and 18 MPa. Failure to achieve this ufter implantation and subsequent healing may result in local fatiguefailure and resorption at the nrck upon resumption of physiological loading.
Engineering Analysis of Shoulder Dystocia in the Human Birth Process by the Finite Element Method
Authors: Meghdari A , Davoodi R , Mesbah F
Published: February 2007

This paper presents an engineering analysis of shoulder dystocia (SD) in the human birth process which usually results in damaging the brachial plexus nerves and the humerus and/or clavicle bones of the baby. The goal is to study these injuries from the mechanical engineering point of view. Two separate finite element models of the neonatal neck and the clavicle bone have been simulated using eight-node three-dimensional elements and beam elements respectively. Simulated models have been analysed under suitable boundary conditions using the ‘SAP80’ finite element package. Finally, results obtained have been verified by comparing them with published clinical and experimental observations.
Smart Structures—a Concept or a Reality?
Authors: Culshaw B
Published: February 2007

A smart structure has intelligence and reaction capability embedded within it. Consequently, via a sensor and actuator network, it can respond to external environmental or operational requirements. The most obvious driving force stimulating the need for smart structures lies within the aerospace industry but civil engineering interests have already exploited the ideas in, for example, compensating for earth tremors. There may even be a potential to be exploited by a future generation of toy manufacturers.

This paper will illustrate the principles underlying the concepts referring to current, evolving and futuristic technologies. It will also assess the present exploitation of the basic ideas and will indicate future trends, making the comparison between European, Japanese and American philosophies towards this rapidly evolving subject.

The successful exploitation of smart structure concepts will prove to be vital in twenty-first-century engineering. Potential paths whereby this exploitation may be realized in a European context will be discussed.
Dover's Smart Bridge
Authors: Taylor N
Published: February 2007

One of the key features of the new ro-ro train ferry berth in Dover Harbour is the computerized control system that governs movement of the associated 105 m long, ship-to-shore bridgework. Representing the first of its kind, the bridge control system ‘senses’ ship movement and changes the bridge geometry to maintain rail stock transit. The robust algorithms are discussed in the context of ‘smart’ structures, in which response to external actions is actively controlled so that specified kinematic parameters are minimized.
A Discrete Control System Model for the Traverse Grinding Process
Authors: Gao Y , Jones B
Published: February 2007

A discrete control system model for the traverse grinding process is established on the basis of the physical laws associated with the process together with mathematical equations describing the workpiece radius distribution and parallelism error. The proposed system model is verified by good agreement obtained from a comparison of the theoretical radius distribution and parallelism error values based on the proposed model with those obtained from a traverse grinding experiment. The control system model is suitable for both plain and multi-diameter roller-type workpieces.
Adaptive Pole Placement Control Using Multiple Transputers
Authors: Anderson A J
Published: February 2007

The paper details the implementation of an adaptive pole placement algorithm on a multiple transputer system. The controller makes use of the extended least squares parameter estimation algorithm and is controlled at the local level by a supervisor task which monitors the behaviour of the control system to ensure robust operation under a variety of environmental conditions. This enhances the integrity of the controller in real-time operations. The adaptive controller is also configured to be used as a node within a distributed control system such that a central network interface can configure a number of individual controllers within the distributed control network. The controller is demonstrated dealing with a plant with changing parameters and disturbances.
Stabilization of the Mechanical Dynamics of a Road Load Simulator Using Classical Control Techniques
Authors: Stringer I A , Bullock K J
Published: February 2007

The open-loop transfer function of a complex hydrostatic pump-motor dynamometer system was derived from an analysis of the dynamics of the individual components. Many system components exhibit non-linearities; however, internal feedback mechanisms contribute to linearization of sub-systems. The resulting model, which was in good agreement with the system's open-loop performance, was used to predict the behaviour of the closed-loop system, this indicated that the system would be unstable.

Classical control theory was used to analyse the performance of a number of stabilizing control strategies, with root locus plots, Bode diagrams and Nichols charts being used to assess the resultant performance. A lead compensation, designed as a differential controller, combined with a bi-linear gain was predicted to provide acceptable speed control. The performance of the system with this controller installed was found to satisfy the design requirements of speed of response, limited overshoot and zero steady-state error.
Experimental Evaluation of a Piezoelectric Actuator for the Control of Vibration in a Cantilever Beam
Authors: Burdess J S , Fawcett J N
Published: February 2007

When an electrical field is applied to a piezoelectric material, the material becomes mechanically strained. If this material is then bonded to a structure, this strain has an accompanying stress, and this can be used to introduce control forces into the structure. The paper considers this method of actuation by experimentally evaluating the use of piezoelectric plates for the purposes of controlling free and forced vibration in a cantilever beam. The control provided by measurements based on acceleration and strain rate is evaluated.
An Optimum Size and Roundness Adaptive Control Method for the Plunge Grinding Process
Authors: Gao Y , Jones B
Published: February 2007

Three plunge grinding control methods are discussed, and it is shown in control engineering terms that the process is one of motion control and that the differences between the various control methods lie in the control algorithms implemented in software using a common hardware system. A new control method is proposed for an improvement in grinding efficiency and is described as the optimum size and roundness adaptive control method. An accurate description of the control actions is provided, and the adaptive algorithm used by the proposed method also enables a low-cost computer system to be used. A case study of the grinding process based on a simulation is presented to demonstrate the benefits of the proposed control method. The experimental results for validating the proposed control method will be the subject of a separate publication.
A Fuzzy Rule-Based Method for Seeking Stable Arc Condition under Short-Circuiting Mode of GMA Welding Process
Authors: Won Y J , Cho H S
Published: February 2007

An unstable arc during welding induces unsound bead, thus resulting in poor mechanical properties at the welded joints. One of the important factors affecting arc stability is the welding voltage/current combination. In practice, a proper combination is usually determined by performing off-line experiments, and no extensive work has been reported on developing on-line searching methods. The paper proposes a systematic on-line method for searching the proper voltage/current combination to provide a stable arc condition in the short-circuiting metal transfer mode. Because the relationship between such welding parameters and the resulting arc stability is excessively complex and non-linear, it is difficult to determine a proper voltage/current combination based on mathematical modelling. To overcome this difficulty, a fuzzy rule-based method is proposed so that the complexity and non-linearity of arc behaviour is effectively represented by adopting fuzzy linguistic rules. The fuzzy rules here are constituted with two fuzzy variables, namely Mita's arc stability index and its derivative with respect to voltage. Then, under experimental conditions, fuzzy inferencing is performed to adjust recursively the voltage/current combination in such a way as to give a stable arc condition. The performance of the proposed searching method is also evaluated through a series of experiments. The experimental results show that the proposed searching method can effectively estimate the proper voltage/current combination to give a stable arc condition.
Model Reference Control of Non-Linear Plants in the Presence of Plant Uncertainties
Authors: Chang K M , Cook P A
Published: February 2007

A model reference control (MRC) scheme based on the hyperstability theory for a class of input-output linearizable non-linear plants is proposed. It is shown that a switching slate feedback gain in this algorithm can reject the effect of the plant uncertainties, if the bounds of the plant uncertainties are known. Hence the boundedness of all signals in the proposed MRC system can be ensured.
Partial State Model Reference Control of an Industrial Oven
Authors: Barrat M , Dorléans P , Villeneuve G , Lécluse Y
Published: February 2007

The partial-state model/reference adaptive controller of Irving et al. and M' Saad is applied to an industrial oven The performances are compared with those of a GPC algorithm. The tracking ability is quite as good, and the control signal is smoother.
Improving Excavator Ergonomics Through the Application of Kinematic Controls
Authors: Schaefer P J M , Howard D
Published: February 2007

A kinematic controller is described that improves the ergonomics of excavator (backhoe) operation, thus increasing work rates and reducing operator fatigue At present, operators have direct control over hydraulic ram velocities, and must synchronize these to achieve the desired motion of the bucket; this requires considerable mental dexterity. Kinematic algorithms are described that give the operator control over bucket velocity in an ergonomically effective coordinate frame. In this way, the synchronization task is performed by the controller rather than by the operator. The results of a simulation study are reported and conclusions are drawn.
Transient Analysis of Power Plant Deaerators
Authors: Bell R D , Rees N W , Lu C X
Published: February 2007

A mathematical model suitable for predicting the transient behaviour of deaerator plant is presented. The model is based on energy and mass balance equations applied to the deaerator, storage tank and feed pump suction pipe. The model parameters are based entirely on the physical characteristics of the plant, and hence the model can be easily adapted to plants of different size. A comparison with data collected from a deaerator plant operating on a 500 MW unit indicates that the model gives good transient responses and can be used to predict accurately the onset of cavitation in the feed pump.
Modelling of a Radial-Piston Hydraulic Motor
Authors: Chappie P J
Published: February 2007

The paper is concerned with the theoretical modelling of the torque-producing mechanism in a radial-piston, eccentric-type, hydraulic motor for low-speed operation. The major difficulty in such an analysis is the description of the frictional losses which, at low speeds, principally result from boundary lubrication conditions. The level of friction is also dependent on the distribution of the transferred forces and the amount of distortion in the bearings These forces vary during the pressure cycle, and squeeze-film effects are introduced between the bearing faces during the period of time following the introduction of pressure into the cylinder.

The interaction between the frictional effect in the connecting rod bearing and the operation of the hydrostatic slipper is central to the modelling process. Friction coefficients in the bearings are determined that predict similar efficiencies to those obtained from test measurements on a low-speed motor. The evaluation of internal motor parameters is then carried out using these coefficient values in the model. Such a model is invaluable for establishing critical areas in the mechanism and for predicting the effect of component design changes on the motor performance.
Fast Evaluation of the Compositional Rule of Inference in Fuzzy Control
Authors: Souami M C , Gill K F
Published: February 2007

Fuzzy production systems can be used to represent procedural knowledge. The proposed fast rule of inference evaluation method opens up the possibility of evaluating, in real time, long productions found in multi-output and decision-support systems. The results obtained show clearly the benefits to be gained by the use of this fast algorithm.
Safety Critical Systems: So What… ?
Authors: Bennett P A
Published: February 2007

Safety critical systems contain advanced computer, microprocessor and software technologies to a degree of sophistication that is frequently beyond the understanding of many practising engineers. Many of these systems control the safe operation of everyday things such as anti-lock braking on cars, personnel lifts and trains, as well as industrial processes and fly-by-wire aircraft. This paper describes the nature, processes, standards and assessment methods currently being employed with safety critical systems, and addresses various questions that the practising engineer may ask. It demonstrates that although the technology and methods may he novel, concerns surrounding the evaluation of safety critical systems are yet another instance of the age-old dilemma involved in exercising engineering judgement.
Automated Fault Analysis for Hydraulic Systems: Part 1: Fundamentals
Authors: Atkinson R M , Montakhab M R , Pillay K D A , Woollons D J , Hogan P A , Burrows C R , Edge K A
Published: February 2007

Early expert systems for fault analysis tended to be based on shallow, heuristic knowledge. For success in engineering applications, it is argued that the complementary knowledge of the underlying principles (deep knowledge) should also be modelled. An object-oriented software library representing models of components of hydraulic circuits is being built using deep knowledge alone. The software modules within this library are reusable for the construction of model-based expert systems for the performance of failure mode and effects analysis and fault tree analysis on any arbitrary hydraulic circuit.
Automated Fault Analysis for Hydraulic Systems: Part 2: Applications
Authors: Hogan P A , Burrows C R , Edge K A , Atkinson R M , Montakhab M R , Woollons D J
Published: February 2007

The paper provides further details of the automated failure modes and effects analysis (FMEA) program outlined in Part 1. Some of the more difficult development problems are discussed, and solutions are presented. The functionality of the program was tested through application to two experimental rigs, namely a closed-loop hydrostatic transmission with a dynamometer and a regenerative pump test rig. Non-destructive faults, such as abnormally low relief valve settings and excessive loads, were manually inserted into these rigs, and the measured effects were compared with the predictions from the program to validate the software. The difference in complexity and configuration evident in the two examples considered serves to highlight the generality of the approach. The ease of reconfigurability of the software reflects the key aim of producing a program capable of analysing a wide range of hydraulic circuits.
Design and Performance Studies of Model-Based Variable-Structure Adaptive Controllers for Industrial Manipulators
Authors: Tso S K , Law P L
Published: February 2007

A model-based variable-structure adaptive control scheme recently proposed for the trajectory tracking of robot manipulators has shown significant promise. By actual implementation with a commercial manipulator, the practical means for improvement are examined, the design trade-offs are systematically explored, and the distinguishing features of the performance achievable in the improved version are brought out and compared with those of earlier schemes.
Coolant Optimization of a Gas Turbine Engine
Authors: Brown A , Jubran B A , Martin B W
Published: February 2007

This paper describes an analysis used to study the performance of the gas turbine engine with particular emphasis on the optimum amount of coolant required for maximum overall efficiency of the engine. The effect of pre-bled air, as well as that drawn from the exit of the compressor, is also studied.

The optimum amount of coolant for the engine is found to depend on the effectiveness of the heat extraction parameter A, component efficiencies of the engine and the compressor pressure ratio of the engine.
The Batch Pyrolysis of Tyre Waste—Fuel Properties of the Derived Pyrolytic Oil and Overall Plant Economics
Authors: Williams P T , Besler S , Taylor D T
Published: February 2007

Estimates for the generation of scrap tyres in the European Community are of the order of 1.5 million tonnes per year, including approximately 0.4 million tonnes per year from the United Kingdom. The majority of the tyre waste is dumped in open or landfill sites but represents a large wasted energy potential. Incineration has been considered as an alternative to dumping in an effort to utilize the high calorific value of scrap tyres; however, this disposal route may not maximize the potential economic recovery of energy and chemical materials from the waste. Pyrolysis of tyres is currently receiving renewed attention, since the derived oils may be used directly as fuels or added to petroleum refinery feedstocks; they may also be an important source of refined chemicals. The derived gases are also useful as fuel and the solid char has the potential to be used either as smokeless fuel, carbon black or activated carbon.

In this paper, halved and whole scrap tyres were pyrolysed in a commercial two tonne per day batch pyrolysis unit at furnace temperatures from 700 to 950°C. The proportion of derived products was dependent on pyrolysis conditions, with a maximum yield of 30 per cent oil. The fuel properties of the derived oils, including calorific value, flash point, carbon residue, viscosity, sulphur content, etc., were analysed and compared to refined petroleum products. In addition the benzene, xylene, toluene, limonene and styrene concentration of the oils was determined to assess the potential of the oils as a source of chemical feedstocks. The oils were also analysed in terms of their chemical composition via liquid chromatography and Fourier transform infra-red spectroscopy and molecular mass range. The pyrolytic oils derived from tyres showed properties that were dependent on pyrolytic conditions and showed fuel properties comparable to those of petroleum products.
Challenging Factors in the Supply and use of Energy
Authors: Railly J W
Published: February 2007

A seminar on ‘Challenging factors in the supply and use of energy’ was held at the Institution of Mechanical Engineers in London on 16 March 1993.
Quantitative Diesel Particulate Analysis Using Gas Chromatography/Mass Spectrometry
Authors: Farrar-Khan J R , Andrews G E , Ishaq R , Williams P T , Battle K D
Published: February 2007

Detailed analysis of the composition of diesel particulate solvent organic fraction (SOF) is difficult for low-level polycyclic aromatic hydrocarbons (PAH) and generally requires pre-separation of aromatic and aliphatic compounds. This is usually done using either on-line or off-line high performance liquid chromatography (HPLC) which complicates the SOF analysis. Without pre-separation of the samples the gas chromatography (GC) cannot resolve the low-level PAH in the presence of higher levels of n-alkanes and other compounds, which may co-elute. A Finnegan Mat ion trap mass spectrometry (MS) detector was used with a Carlo Erba Mega GC to analyse diesel fuel, diesel particulate SOF and oil without pre-separation. It was shown that the mass number of PAH could easily be extracted from the total ion chromatogram and low-level PAH quantified without pre-separation. A standard calibration mix of PAH covering the mass range of interest was used and the computer software developed to search for and quantify them automatically. This calibration mixture could also be used for the quantification of any other PAH. Pre-separation of the SOF was only necessary for very low-level PA H in the ppb range.
The 900 MW Combined Cycle Gas Turbine Power Station Project at Killingholme
Authors: Chappell T E
Published: February 2007

PowerGen's 900 MW combined cycle gas turbine (CCGT) power station at Killingholme achieved full load output over two months before the scheduled date for full commercial load and less than 34 months after the turnkey contract was placed. This paper reviews the development of PowerGen's first CCGT power station, discusses the reasons for the choice of this type of plant and examines early operating experience. The contract strategy, a technical description of the plant, the project programme and the environmental impact of the plant relative to a conventional coal-fired power station are also included.
Derivation of the Torque—Speed Characteristic of a Reaction Turbine
Authors: Levy D
Published: February 2007

When a reaction turbine is coupled to a generator or when an electric motor is coupled to a pump, the torque–speed characteristic of the runner needs to be known so that the control engineer can analyse the system for stability and optimal operation. The currently used one-dimensional vector analysis applies only where there is smooth flow in the inlet of the machine.

This paper modifies and extends this analysis to apply to a variable flow situation which occurs when the load on the machine is not equal to the optimal specified load. Runaway speed and starting torque of the machine can also be calculated using this analysis.
Development of the Trilateral Flash Cycle System: Part 1: Fundamental Considerations
Authors: Smith I K
Published: February 2007

The world market for systems for power recovery from low-grade heat sources is of the order of £1 billion per annum. Many of these sources are hot liquids or gases from which conventional power systems convert less than 2.5 per cent of the available heat into useful power when the fluid is initially at a temperature of 100° C rising to 8–9 per cent at an initial temperature of 200°C. Consideration of the maximum work recoverable from such single-phase heat sources leads to the concept of an ideal trilateral cycle as the optimum means of power recovery. The trilateral flash cycle (TFC) system is one means of approaching this ideal which involves liquid heating only and two-phase expansion of vapour. Previous work related to this is reviewed and details of analytical studies are given which compare such a system with various types of simple Rankine cycle. It is shown that provided two-phase expanders can be made to attain adiabatic efficiencies of more than 75 per cent, the TFC system can produce outputs of up to 80 per cent more than simple Rankine cycle systems in the recovery of power from hot liquid streams in the 100–200°C temperature range. The estimated cost per unit net output is approximately equal to that of Rankine cycle systems. The preferred working fluids for TFC power plants are light hydrocarbons.
Low-leakage and High-Flow Regenerators for Gas Turbine Engines
Authors: Wilson D G
Published: February 2007

The preliminary analysis and development of two new forms of regenerative heat exchanger that seem to promise greatly improved performance characteristics is described. To reduce drastically the usually high leakage and high seal wear rates suffered by present rotary regenerators, discontinuous rotation of the matrix has been studied, with seals that clamp the matrix during the stationary periods. To enable the regenerative gas turbine cycle to be used at high powers, regenerators consisting of movable ceramic modules are being investigated. The potential applications of the discontinuous-rotation type are particularly to small lightweight gas turbine engines such as those for automotive applications and to helicopters and light turboprop aircraft. The modular regenerator is being studied in application to burning coal and biomass of gas turbine engines and to larger marine and stationary base-power engines with power outputs of up to (and possibly beyond) 100 MW.
The Supplementary-Fired Exhaust-Heated Cycle for Coal, Wood and Refuse-Derived Fuel
Authors: Wilson D G
Published: February 2007

An analysis is presented of a system that would enable refuse-derived fuel (RDF) (produced from, principally, paper) or other biomass (for example wood chips) or coal to be burned cleanly in a highly efficient gas turbine system of a size that would match the needs of many communities (a solid waste flow of 1000–3000 tons per day). The system consists of a gas turbine engine with two principal and several minor additions. The principal additions are a combustor to burn the RDF at approximately atmospheric pressure in the hot turbine exhaust flow and a high-temperature heat exchanger to transfer heat from this stream to the compressed air leaving the compressor. A design-point thermal efficiency of 55–60 per cent and high off-design efficiencies are predicted for the most favourable configuration with components designed for the purpose. About half the heat input would come from the RDF and half from conventional gas turbine liquid or gas fuel.

In this paper the possible alternative configurations of such a plant are discussed, the thermodynamic implications are reviewed and some typical component performance values are introduced so that the overall plant performance can be predicted.
Gas Turbines in Cogeneration and Utility, Industrial and Independent Power Generation
Authors: Moore M J
Published: February 2007

The Seventh ASME Cogen Turbo Power Congress and Exposition was held at the Bournemouth International Centre on 21–23 September 1993.
Social Issues and Environmental Implications
Authors: Hann James
Published: February 2007

This paper outlines the main problems and issues facing the world today and describes the potential relevance of nuclear energy to them. Five themes are chosen: the new world order, instability of the former communist bloc, the exploding world population, the ecological balance and the enfeebled capacity of the West. It is hoped that governments in the West can be persuaded to increase the nuclear capacity in order to cope with problems that will arise in the future.
Nuclear Power in the United Kingdom—the End of the Beginning?
Authors: Collier J G
Published: February 2007

Nuclear power is a young technology that has developed within a political environment of ever-changing priorities. In the United Kingdom, Government-led central planning of electricity supply has given way to market forces and the future of nuclear power depends on its ability to compete in this competitive environment as well as its wider public acceptance. In only three years, the disciplines of private sector competition have transformed the economics of United Kingdom nuclear operations and the new generation of pressurized water reactor (PWR) at Sizewell is set to lead the world in safety and performance. Taken together with the growing recognition of the need to protect the local and global environment from the products of the combustion of fossil fuels, the prospects for the future of nuclear power as the major clean energy source for the twenty-first century have never been better.
Nuclear Power Generation in Japan—Present Status and Future Prospects
Authors: Sekine Y
Published: February 2007

The paper outlines the present status and future prospects of nuclear power generation in Japan with emphasis on the situations peculiar to Japan. It first describes why among the many kinds of energy resources available, Japan has decided to follow a nuclear energy policy. Next presented is the current status of nuclear power generation with a brief review of nuclear power technology development. All phases of nuclear power generation from procurement of nuclear fuel to the waste disposal are covered.

Social, political and technological problems that the Japanese electric power industry has to tackle in order to utilize fully nuclear energy are also discussed, together with the new technologies that will need to be developed to solve the problems effectively.

As many quantitative data as possible are presented throughout the paper to provide a precise description.
Safety Design Philosophy of Mitsubishi PWRs
Authors: Hakata T , Kitamura T
Published: February 2007

The basic safety design philosophy of Mitsubishi pressurized water reactors (PWRs) is discussed and compared with the British PWR. PWR plants are designed in accordance with the Japanese regulatory guidelines which are similar to American and International Atomic Energy Agency (IAEA) safety criteria and are based on defence-in-depth principles. The high reliability of nuclear power plants is especially emphasized in Mitsubishi PWRs, and this has been demonstrated by the good operating experience of PWR plants in Japan. The safety system designs of six key items, which were discussed in the recent review of overseas designs by British utilities, are addressed to show the difference in the design philosophy between the United Kingdom and Japan.
Electricity Production from a Pulsed Tokamak Fusion Reactor
Authors: Hancox R , Boulton M , Karditsas P , Murphy T
Published: February 2007

A study has been undertaken to investigate the use of a possible pulsed fusion reactor to supply the national grid. Detailed models of the individual components of a 1200 MWe reactor plant were developed, including the reactor blanket, boiler and turbine generator. Using a drum boiler as a thermal energy store, full output could be maintained for reactor off-periods up to only 40 seconds, compared with an expected off-period for a pulsed tokamak fusion reactor of up to 300 seconds. Two possible solutions to this mis-match problem are considered, the first involving an externally fired superheater and reheater, which would allow the off-period to be extended to 105 seconds, and a second involving an auxiliary boiler, which would allow an indefinite off-period. Under these conditions, the plant and operating costs are estimated to be higher than the estimated cost of incorporating non-inductive current drive into a tokamak, and therefore the study suggests that it would be advantageous to develop a continuously operating tokamak fusion reactor, although other possible solutions relevant to the pulse operation should be further investigated.
Semi-Solid Processing of Aluminium and High Melting Point Alloys
Authors: Kapranos P , Kirkwood D H , Sellars C M
Published: February 2007

Thixoforging (a semi-solid metal-forming process) of non-dendritic A357 aluminium alloy has been studied to assess the effects of process variables on the component integrity. Complete filling of the dies required ram velocities in excess of 300 mm/s and centre-line porosity in the thixoforged components was reduced by ram loads up to 55 kN. The mechanical properties of these thixoforgings were superior to conventionally cast alloy. Some work has also been carried out on M2 tool steel and Stellite 21 to demonstrate that these alloys may be thixoforged to complex shapes with good mechanical properties.
Parameterized Object Design Using a Geometrical Construction Representation
Authors: Tan S T , Yuen M M F , Yu K M
Published: February 2007

This paper proposes a geometrical construction interpretation of variational geometry for achieving parameterized object definition. Vector geometry is used to represent the various kinds of geometrical entities while dimensions are defined to have directional sense. Geometrical constructions are then used to link up all geometrical entities and dimensions of a solid in a meaningful way, to represent the variational geometry properly. The geometrical construction scheme is implemented in a prototype modeller using polyhedral solids as examples.
Surface Roughness Model for Turning Grey Cast Iron (154 BHN)
Authors: Baradie M A El
Published: February 2007

Computerized machinability data systems are essential for the selection of optimum cutting conditions during process planning, and they form an important component in the implementation of computer integrated manufacturing (CIM) systems.

This paper presents a study of the development of a surface roughness model for turning grey cast iron (154 BHN), using tipped carbide tools under dry conditions and a constant depth of cut. The model is developed in terms of cutting speed, feedrate and nose radius of the cutting tool. These variables were investigated using design of experiments and utilization of the response surface methodology (RSM). A first-order equation covering the speed range 110–350 m/min and a second-order generation equation covering the speed range 80–495 m/min are presented. The results are given in terms of mean values with confidence intervals.
Large Electrical Machines: Powering a Business Renaissance for the Twenty-First Century
Authors: Lloyd M R , Mason M
Published: February 2007

GEC ALSTHOM Large Machines Limited is a traditional heavy engineering company specializing in electrical machines (Fig. 1), and has successfully evolved over 90 years of operation. This historical success, however, led to a very functionalized layout of workshops and facilities totally unsuited to the present dynamic world market.

Through a company-wide improvement programme the company has been restructured within the existing buildings and site to take advantage of the latest cellular technology, using numerous innovative concepts in manufacture and adoption of just in time (JIT), total quality management (TQM) and design for manufacture (DFM) concepts in a low volume manufacturing environment.

The project involved the complete redesign of the factory layout, introduction of new products and equipment and concepts, resulting in dramatically improved leadtimes, inventories and sales per employee.

The case study is probably unique in that the programme was executed while increasing full production and involved the adoption of techniques often only associated with volume manufacture.
Making Circuits More than Once: The Manufacturing Challenges of Electronics Intensive Products
Authors: Williams D J , Conway P P , Whalley D C
Published: February 2007

This paper is a review of some of the problems facing manufacturers of current and future generation electronic products. It presents a brief overview of work carried out by the Interconnection Group at Loughborough in the support of manufacturing industry, and in particular defines some of the limitations of the manufacturing processes. The paper closes by identifying research areas that can be addressed by the academic community to assist industry in its efforts to maintain competitiveness. Research areas focused on are conventional packaging, multi-chip modules and some aspects of the organization of international manufacture.
Design System Mfk—An Important Step towards an Engineering Workbench
Authors: Meerkamm H
Published: February 2007

The Design System mfk will support the designer by an object-orientated synthesis of parts and an integrated knowledge-based analysis. An own-product model which is completely independent from the data structure of the used computer aided design (CAD) system contains all necessary information on geometry, technology, function and organization. It allows different types of analysis: design for production, tolerance analysis, cost and stress calculation, repeated component search, etc. Usable for products of higher complexity the Design System can be seen as an approach to an engineering workbench.
CAPTD: A Low-Cost Integrated Computer Aided Design System for Press Tool Design
Authors: Ismail H S , Hon K K B , Huang K
Published: February 2007

This paper describes the structure and operation of a low-cost computer aided design system for press tool design (CAPTD). The system is a collection of integrated industry standard microcomputer packages and purpose-built programs. The packages include AutoCad 11, for the input of workpiece geometry and the output of the press tool part and assembly drawings, and dBase IV for the decision support, the selection of press tool components and generating output reports. A purpose built ‘C’ program is also developed for the layout and nesting of the workpiece. The system is driven by a set of press tool design rules implemented in both the dBase IV and ‘C’ programming languages. The system is developed to run on 80386SX or higher based IBM-compatible microcomputers.
CIM-OSA and Stochastic Time Petri Nets for Behavioural Modelling and Model Handling in CIM Systems Design and Building
Authors: Aguiar M W C , Weston R H
Published: February 2007

Means are considered that can structure design and building processes associated with integrated manufacturing systems. To meet the identified needs, the paper proposes the use of an environment for executing models which adopts and extends the concepts and guidelines identified by the CIM-OSA (computer integrated manufacturing-open sytems architecture) consortium.

A key component of the environment concerns the execution of models of behaviour. The paper describes (with reference to on-going implementation work) how CIM-OSA behaviour models can be represented and handled by stochastic time Petri net model execution tools.

The use of the design and building environment is illustrated with reference to a case study application involving the batch manufacture of a family of electronic products. Here, the necessary form of key CIM-OSA and Petri net models are described, as are results from the Petri net simulation studies. The paper also comments on the advantages and limitations of the CIM-OSA modelling approach and how certain of those limitations are circumvented by adopting the proposed environment for model execution.
Plane Strain Rigid Plastic Finite Element Formulation for Sheet Metal Forming Processes
Authors: Martins P A F , Marques M J M Barata
Published: February 2007

A rigid plastic finite element model for analysing two-dimensional plane strain sheet metal forming processes is described. The model is based on the large strain formulation using membrane theory, and the material is assumed to be rigid plastic, work hardening and conforms to Hill's anisotropic yield criterion and associated flow rules. The theoretical development follows the work of Kobayashi and Kim on the axisymmetric modelling of sheet metal forming. An application of the model for plane strain cylindrical punch stretching is presented. The results obtained are compared with those provided through an analytical membrane solution described in this work. The agreement found between both solutions is excellent.
Effects of Longitudinal Vibration on the Mechanical Properties of Mild Steel Weldments
Authors: Tewari S P , Shanker A
Published: February 2007

This paper deals with the effect of longitudinal vibration on the mechanical properties of mild steel weldments. The weldments were prepared under different frequencies and amplitudes of vibration. Experiment was carried out in the frequency and amplitude ranges of 0-400 Hz and 0-40 μm respectively.

It is found that yield strength, ultimate tensile strength and hardness improves for mild steel specimens welded under vibratory conditions. It is further observed that this improvement in the mechanical properties is appreciable up to 30 μm amplitude.
Trajectory Planning Using Artificial Intelligence
Authors: Eroglu M , Gill K F
Published: February 2007

In this paper, the aim is to introduce artificial intelligence techniques into trajectory planning and obstacle avoidance, to achieve the minimum time trajectory. The method presented has many areas of application including NC/CNC (numerically controlled/computer numerically controlled) machining operations, precision assembly and transportation problems.
Tool Life and Tool Quality in Bulk Metal Forming
Authors: Cser L , Geiger M , Lange K , Kals J A G , Hänsel M
Published: February 2007

Due to their intermediate position between the machine and workpiece, tools represent the interface of the manufacturing system to the process. Near net shape production, new materials and techniques are the new challenges in metal forming and especially in tooling. A significant economical effect can be achieved through an increase in the life of tool elements, as well as through proper tool management strategies. The greatest problem connected with the preliminary estimation of tool life is the large scatter of service life for a series of identically designed tools. The uncertainty in estimating the expected service life of tools and thus the tooling costs per piece is caused by the enormous variety and confluence of damaging factors, the factory-specific character of tool life and the stochastic phenomenon of tool failures. From the confluence of aspects influencing tool life it is clear that there is no general recipe for increasing tool life and tool quality. Each of the influencing aspects contains some possibilities for increasing the service time of tools. This paper shows some examples of tool design and tool manufacturing and points out that a knowledge-based approach imitating the activity and knowledge acquisition of human experts can be the bridge between computer aided (CA) techniques and human experience in predicting expected tool life.
CAD Applied to Twist Drills
Authors: McColl M , Leadbetter R
Published: February 2007

A computer aided design (CAD) modeller has been developed to facilitate the design of twist drills. A feature of the system is its ability to accept both the theoretical mathematical parameters used by drill theorists and those parameters used as standard nomenclature in the drill industry. Differences between the theoretical and ‘real’ drills are accounted for. The program presents a variety of views of the three-dimensional drill model and provides relevant numerical information. The CAD modeller is a platform for a greater computer aided engineering (CAE) system, which is involved from the initial design stage through to manufacture.