bluuebunny/crossref_metadata_2025 huggingface dataset:
Pressurization of Bone Cement under Standard, Flanged and Custom Acetabular Components for Total Hip Replacement
Authors: Beverland D E , Kernohan W G , Nixon J R , Orr J F , Watson P
Published: February 2007

Custom acetabular components are proposed to achieve uniform cement mantles, even in irregular acetabula presented at revision, in order to enhance fixation. One aim of developing custom components was to permit pressurization of bone cement by the components at insertion and maintain the pressure during polymerization. A model acetabulum was set up for the insertion of standard, flanged and custom components under constant force. Cement pressure was measured at the floor of the acetabulum by means of a piezoelectric diaphragm transducer. Polythene tubes were inserted in the model acetabular walls to estimate penetration of cement into cancellous bone.

Insertion of the standard and flanged components caused cement pressures up to 106 kPa which decayed to less than 21 kPa as cement escaped at the rim and the components came into contact with the acetabulum. The custom component maintained a pressure of over 60 kPa during polymerization from an initial pressure of 105 kPa and examination of cement mantles on removal showed no evidence of contact. The custom component also showed enhanced penetration of cement, especially around the rim of the acetabulum. It is concluded that the custom component design achieves higher cement pressures and that better fixation will result.
Load Concentrations around Crystal Aggregates in Articular Cartilage under Short-Term Loading
Authors: Clift S E , Hayes A , Miles A W , Harris B , Dieppe P A
Published: February 2007

The deposition of crystals in joints is a feature of a number of joint diseases. Crystals are frequently observed on the surface of articular cartilage and in the mid-zone. The purpose of this investigation was to model the stress concentrations in the mid-zone of the cartilage layer arising from the presence of large crystal aggregates. Scanning electron microscopy was used to determine the geometry and distribution of crystal aggregates within the cartilage layer. Finite element and photoelastic approaches were then used to predict the stress distribution around spherical aggregates 50 and 100 μm in diameter. The implication of the results is that very densely packed and tightly bound spherical aggregates will themselves carry a certain amount of load. However, less tightly packed aggregates, perhaps interspersed with fibrous tissue, are potentially much more damaging.
Wear of Articular Cartilage: The Effect of Crystals
Authors: Hayes A , Harris B , Dieppe P A , Clift S E
Published: February 2007

An investigation of the effect of crystals in a lubricant on the wear of articular cartilage in vitro was carried out in order to examine the hypothesis that crystals present in synovial fluid could cause abrasive damage of the articular surface. Plugs of cartilage were worn against a stainless steel counterface in a pin-on-disc wear rig. The concentration of cartilage debris present in the lubricant was assessed by measuring the bound sulphate originating from the glycosaminoglycans by ion chromatography. Results indicated that the presence of crystals in the lubricant significantly increased the concentration of wear debris and that the crystal size and morphology influenced the type of damage sustained by the cartilage. Other experimental evidence suggested that cartilage scratched in vivo was no more susceptible to further in vitro damage in this experimental model than normal cartilage. These results implied that crystals present in the synovial fluid of arthritic joints have the potential to cause excessive wear of the articular surface, but that if such crystals are removed the scratched cartilage may not be susceptible to any further damage by abrasive wear.
Grip Strength and Endurance in Rock Climbers
Authors: Cutis A , Bollen S R
Published: February 2007

The performance of competition climbers in laboratory-based tests of pinch and whole hand grip strength and endurance was compared to that of non-climbers of the same age, sex and physique. Climbers performed significantly better, indicating higher stresses acting in the flexor mechanism, possibly predisposing injury. Attempts were made to correlate the performance in the tests to climbing achievement, measured by current technical climbing standards. Although pinch grip strength increased with the length of climbing experience, there was no evidence that strength in the hands alone guarantees success in competition climbing.
A Biomechanical Analysis of the Plantar Surface of Soccer Shoes
Authors: Majid F , Bader D L
Published: February 2007

The incidence of severe injuries for soccer players may lead to long-term inactivity or, at worst, retirement from the game. Many of these injuries, particularly those involving the lower leg, can be attributed to adverse physical conditions at the interface between the soccer shoe and the playing support surface. This study investigated the biomechanical characteristics at this interface for a range of proprietary soccer shoes. An experimental system was designed and developed which, via a weighted pendulum arm making contact with a vertical column, provided controlled rotation of the forefoot of the soccer shoe on samples of playing surfaces. The overall rotation was found to depend on several physical and material factors. For example, the size 7 soccer shoes produced a statistically significant increase in axial rotation for the same impact energy compared to the larger sized shoes under test. In addition, flat soled shoes, designed for synthetic playing surfaces, produced consistently smaller rotations than shoes with either moulded or screw-in studs, although this finding depended on the moisture content of the playing surface. The pressure distribution within several soccer shoes was also measured using the F-Scan Gait Analysis System, for a subject walking across a grass surface. Results indicated differences in pressure distribution over the first metatarsal area of the foot, in existing shoe designs.
Error and Data Coding in the Multi-Dimensional Analysis of Human Movement Signals
Authors: Loslever P
Published: February 2007

This paper discusses two main problems of human motion data: their uncertainty and analysis. Considering the first point, a simulating method is proposed to assess the error. This approach is applied to a joint angle, computed from the positions of points obtained through a three-dimensional video-computer system. Considering the second point, a multi-variate methodology based on appropriate data coding and the correspondence factor analysis method is proposed. The outcomes of this allow the relations within the time windows of the variable set, the distances within the observation set and the correspondences between these two sets to be shown graphically. To illustrate this approach, two examples are considered: the analysis of the low back-pelvis angle in an ergonomical study about the sitting posture and the analysis of joint angles in the gait.
Pre-Clinical Testing of Hip Prosthetic Designs: A Comparison of Finite Element Calculations and Laboratory Tests
Authors: Verdonschot N J J , Huiskes R , Freeman M A R
Published: February 2007

To investigate the accuracy of finite element (FE) models for pre-clinical testing of unbonded hip prostheses, relative to aspects of load transfer and micromobility, two previously published laboratory experiments were simulated, using three-dimensional FE models. It was found for the load-transfer analyses that the experiment and the FE study revealed results that were very similar. The trends in the mobility experiments were also reproduced in the FE simulations, although quantitative differences were found. It is concluded that FE analysis can effectively be used for design evaluation of hip prostheses before prototypes are made.
Metacarpophalangeal Joint Prostheses: A Review of past and Current Designs
Authors: Beevers D J , Seedhom B B
Published: February 2007

The anatomy and biomechanics of the metacarpophalangeal (MCP) joint are briefly described. Hinge, flexible and surface designs of past and current MCP prosthetic joints are reviewed, outlining their respective advantages and disadvantages. Although existing prostheses can restore cosmetic appearance and relieve pain, none can equal the stability and versatility of the natural joint. Delayed reconstructive surgery may be partly responsible for the mediocre results experienced, since the later the surgery the worse will be the condition of the muscles and ligaments surrounding the joint. These are the structures responsible for strength, movement and stability of the joint. From a mechanical viewpoint it may be desirable to operate at an earlier stage of the disease than is currently indicated, but this is a clinical decision. Some design aspects, namely fixation and wear, require a different approach when designing an MCP prosthesis from that adopted in the case of prosthetic hips and knees.
A Kinematic Technique for Describing Wrist Joint Motion: Analysis of Configuration Space Plots
Authors: Moore J A , Small C F , Bryant J T , Ellis R E , Pichora D R , Hollister A M
Published: February 2007

This paper describes an experimental method for determining the minimum number of degrees of freedom of a human joint. Application of this technique to the wrist suggests that the normal, intact wrist joint uses only two degrees of freedom to move in a plane that is not aligned with the anatomic planes. The technique may be useful in identifying emerging joint pathologies and in simplifying kinematic models of joint function.
Interaction between the Joints in the Shoulder Mechanism: The Function of the Costoclavicular, Conoid and Trapezoid Ligaments
Authors: Pronk G M , van der Helm F C T , Rozendaal L A
Published: February 2007

By developing a measurement method based on the palpation of bony landmarks, the three-dimensional positions of the scapula and clavicle can be measured at several angles of humerus elevation. An analysis of these measurements shows the interaction between all joints of the shoulder mechanism. With the help of a biomechanical shoulder model the role of some of the extracapsular ligaments in the motion pattern of scapula and clavicle can be derived. In addition, the interaction between the rotations in the acromioclavicular and sternoclavicular joints is shown, and the possible implications for the treatment of joint problems in the shoulder are discussed.
Strain Gauged Six-Component Load Transducer for use in Upper Limb Biomechanics
Authors: Runciman R J , Nicol A C
Published: February 2007

A six-channel instrumented load transducer has been developed for measuring hand and upper limb loading (maximum design load, 2 kN). Modular in design, the transducer can be adapted to a variety of formats, thereby increasing the range of activities to which it can be applied. When used with a motion analysis system, hand loading can be determined with respect to a laboratory coordinate system irrespective of transducer orientation and position. Measurement accuracy of approximately ± 1 per cent of applied loading has been determined through a system calibration.
Utilization of Upper Limb Joint Replacements during 1972–90: The Mayo Clinic Experience
Authors: Madhok R , Lewallen D G , Wallrichs S L , Ilstrup D M , Melton L J
Published: February 2007

Increasing application of expensive medical technologies, including joint replacement, is of concern in the current economic climate. Successful upper limb joint replacements (ULJRs) are being performed, but few detailed data about their utilization are available. To explore the resource implications of such surgery, the utilization of total shoulder replacement (TSR), total elbow replacement (TER) and total wrist replacement (TWR) were examined from the time these procedures first became available at the Mayo Clinic up to 1990. The age- and sex-adjusted utilization rate for TSR among Olmsted County, Minnesota, residents was 1.8 per 100000 person-years (p-y), 0.8 per 100000 p-y for TER and 1.1 per 100000 p-y for TWR. Overall utilization of primary ULJR among Olmsted County residents during the 19-year study period was 3.8 per 100000 p-y. The commonest indication for TSR was osteoarthritis (46 per cent) and for TER and TWR was rheumatoid arthritis (50 and 81 per cent respectively). There was no consistent trend in the utilization of these procedures among Olmsted County residents, but the number of referral patients receiving a ULJR at the Mayo Clinic increased steadily during the study period. The Mayo Clinic experience suggests an increasing demand for ULJR, particularly TSR and TER. With continued advances in, and diffusion of, the technology this demand may increase further.
Decoupling Vibration Control of a Flexible Rotor System with Symmetric Mass and Stiffness Properties
Authors: Chen S T , Lee A C
Published: February 2007

The paper investigates the control problem for a flexible rotor system with symmetric mass and stiffness properties and proposes an internal and external decoupling control scheme to simplify the controller design for such a system, where the existence of gyroscopic effects during rotation is neglected. The whole flexible rotor system can eventually be separated into four flexible subsystems without knowledge of the system parameters, and the control algorithm for each subsystem can be designed and implemented independently. Simulation results demonstrate the effectiveness of using the proposed scheme in conjunction with the optimal modal space control scheme.
Variable-Structure Linear-Model-Following Control of Manipulators
Authors: Tso S K , Lai M L , Law P L
Published: February 2007

The paper describes the interaction between modelling, control and adaptation of a variable-structure model-following method applied to highly non-linear plants. The method is particularly appealing in the control of high-performance robot manipulators. The problems concerned with its application are discussed with reference to the use of a controller in a commercial manipulator as a case study.
Angular Position Control of Objects Using a Transputer-Based Vision System and Fuzzy Logic Techniques
Authors: Ekerol H , Hodgson D C
Published: February 2007

A demonstrator system for closed-loop control of rectangular objects by non-contacting means is developed. The system consists of a transputer-based vision system and two power air jets actuated by piezoelectric translators. The first air jet is employed to give the initial angular displacement and the second for correcting any positional errors during the passage of the object in front of it. The overall control algorithm employs fuzzy logic techniques. The potential use of the system in industry for collating soft or brittle products moving on conveyor belts, before being fed into cartoning machinery, is also discussed.
Estimation of Acceleration from Data with Quantization Errors Using Central Finite-Difference Methods
Authors: Harrison A J , McMahon C A
Published: February 2007

The paper considers the problem of generating derivatives of measured data when appropriate transducers and/or observers are not available. Six methods or schemes for estimating acceleration (or generally the second derivative of one parameter with respect to another), by central finite-difference methods, are described. Each scheme is subject to two principal sources of error: noisy or quantized data and the presence of ignored high-order derivatives of motion. The first of these increases with sampling frequency, and the second decreases. There is thus an optimal frequency of sampling for each scheme, dependent on the system signal/noise ratio, the signal- frequency content and the order of the derivative modelled by the scheme. Tables are given that enable the investigator to select the most accurate scheme for a given signal/noise ratio and a desired sampling-frequency I signal-frequency ratio, together with estimates of the resulting combined mean absolute error from the two sources. The results are confirmed experimentally.
Review of Optimal Solutions to the Robustness Problem in Observer-Based Fault Detection
Authors: Frank P M , Koppen B
Published: February 2007

The paper presents a unified approach and general solution of the robustness problem in fault detection and isolation concepts. The ultimate objective is the design of an unknown input fault-detection observer providing a perfect decoupling between unknown inputs and faults. If this is not possible because certain prerequisites are not fulfilled, two optimal compromises in the time domain and in the frequency domain are described. The basic definitions concerning robustness and unknown input fault detectability are given, and the design techniques for the proposed approaches are outlined. The cross-connections to other methods are discussed and a practical example is given.
Robust Controllers for Pulse-Width-Modulated D.C./D.C. Converters Using Internal-Model-Control Design
Authors: Garabandić D , Petrović T
Published: February 2007

A linear feedback controller for pulse-width-modulated d.c./d.c. regulator is designed using a frequency domain optimization method based on internal-model-control theory. This method aims to produce suboptimal low-order controllers which are ‘robust’, in the sense that the closed-loop system is guaranteed to meet stability objectives in the presence of model uncertainty. The small-signal model of a d.c./d.c. converter is used for the controller design. The model uncertainty description derived here is based on experiments and non-linear modelling. The result of the synthesis is a family of controllers, and each member of this family satisfies the robust control objectives. All controllers have a multi-loop structure including two feedback loops and one feedforward loop. A detailed design of the controller, including experimental results, is presented.
An Uncertainty-Attenuating Controller for Mechanical Manipulators with Electromechanical Dynamics
Authors: Zhu H A , Teo C L , Hong G S
Published: February 2007

It is known that the cross-coupled non-linear electromechanical dynamics of motor-manipulator systems is more complex than when only the mechanical dynamics is considered. In this paper, control of manipulators with non-negligible motor dynamics is studied and a control strategy is developed for achieving ease of controller design and high control performance. By using the developed algorithm not only can the highly complicated electromechanical dynamics be effectively controlled, but also the motors are made ‘sensible’ to sense and compensate for the uncertain dynamics acting at the manipulator joints. What is more, as an encouraging by-result, the difficulty and complexity in modelling and controlling such systems can be reduced significantly.
A Finite Element Model of Hydraulic Pipelines using an Optimized Interlacing Grid System
Authors: Sanada K , Richards C W , Longmore D K , Johnston D N
Published: February 2007

Simulation of flow and pressure variations in fluid pipelines using finite difference and finite element models can give unrealistic results, corresponding to errors in natural frequencies. A novel finite element model of hydraulic pipelines has been developed, using an interlacing grid system. The grid spacing is non-uniform and is optimized, using a genetic algorithm, to make some or all of the undamped natural frequencies of the model as close as possible to exact theoretical ones for a uniform pipe with the extreme boundary conditions of either constant pressure or no flow. Inaccuracies in the highest natural frequencies may be acceptable because of the effect of frequency-dependent friction and limited system frequency response. The optimized model gives accurate results in time domain simulation, and it allows variable properties and a variable integration step to be readily accommodated.
Comparative Aspects of Neural Network Algorithms for On-Line Modelling of Dynamic Processes
Authors: An P E , Brown M , Harris C J , Chen S
Published: February 2007

This paper reviews the model structures and learning rules of four commonly used artificial neural networks: the cerebellar model articulation controller (CMAC), B-splines, radial basis functions (RBF) and multi-layered perceptron (MLP) networks. Their dynamic modelling abilities are compared using a two-dimensional non-linear noisy time series. The network performances are evaluated based on their network surface plots, phase/time history plots, learning curves, prediction error autocorrelation functions and finally their short-range prediction error variances. The modelling results suggest that all four networks were able to capture the underlying dynamics of the time series. Also, specific prior knowledge about the time series was incorporated into the B-splines model, and is used to highlight an important trade-off between the model flexibility and high-dimensional modelling ability in the B-splines and CM AC networks. In general, when the network model is well conditioned and linear with respect to its adaptable parameters, simpler on-line learning rules often provide adequate convergence properties. Alternatively, when the model is highly non-linear, complicated learning rules which utilize high-order gradient information are generally required at the expense of increased computational complexity.
Multi-Rate Generalized Predictive Control for Multi-Variable Systems
Authors: Park I O , Oh J H
Published: February 2007

The purpose of this paper is to drive the adaptive multi-rate generalized predictive control for multi-variable systems in a stochastic framework. Modelling disturbances as white noise is inadequate for process control because most disturbances encountered in process control are coloured or non-stationary in nature. For that reason a stochastic parallel model identification algorithm for a multi-rate-sampled system is proposed. No attempt is made to identify the noise model. Hence the algorithm is applicable to any measurement noise case. The measurement noise can be arbitrary (for example coloured or non-stationary noise), except for the assumption that it and control inputs are stochastically uncorrelated. Then the control algorithm based on the generalized predictive control is proposed. In order to demonstrate the effectiveness of the proposed control algorithm a simulation study is carried out. The closed-loop performances are excellent.
Notes on Multi-Step Ahead Prediction Based on the Principle of Concatenation
Authors: Rossiter J A
Published: February 2007

A recent paper by Kaynak in this Journal proposes a more efficient application of generalized predictive control than that of Clarke et al., the most common in the literature. In this technical note, Kaynak's algorithm is compared with two other algorithms of Kouvaritakis and Rossiter, already in the literature, and also with the original algorithm of Clarke et al., and it is demonstrated that they all in fact reduce to the same algorithm. Moreover, it is shown that the earlier algorithms are more efficient in the non-adaptive case and that Kaynak's algorithm is not efficient in the adaptive case.
LNG Power Recovery
Authors: Wong W
Published: February 2007

The thermal efficiency of a Carnot cycle is limited by the maximum and minimum temperatures available. The construction of LNG (liquid natural gas) terminals and the need to vaporize LNG offers a cooling source at a very much lower temperature than sea water. By using the cold sink and by adapting the waste heat available from a combined cycle plant, it is possible to recover power from the vaporization of LNG. This is done by the use of a reverse cascade refrigeration process where energy is extracted by expanders instead of energy input by compressors.

The paper explains how the hot and cold processes can be integrated to produce a compound cycle with an overall efficiency of some 55 per cent or more depending on the quantity of LNG to be vaporized. Special reference is given to the features needed for the rotating equipment and how equipment selection is critical to the realization of a practical working power station.
An Improvement of Part Load Performance of Diesel Engines Operating at Constant Speed Conditions
Authors: Abdel-Rahman A A , Ibrahim M K , Said A A
Published: February 2007

This paper discusses the possibility of improving the part load performance of diesel electric turbocharged engines operating at constant speed conditions. A sequential turbocharged system is proposed, where the compressors are connected In series. The study focused on two turbocharged diesel–electric generating sets existing at Ameria Petroleum Refining Company in Alexandria, Egypt. The results of the prediction showed that, at part load, both the maximum pressure and temperature were increased, and the brake specific fuel consumption was reduced considerably (by about 10 per cent).
The Interaction of the Precessing Vortex Core and Reverse Flow Zone in the Exhaust of a Swirl Burner
Authors: Syred N , O'Doherty T , Froud D
Published: February 2007

This paper describes recent work at Cardiff to gain further understanding of the fundamental processes occurring in swirl burners. The phenomenon of the precessing vortex core has been characterized via the use of a two-component laser anemometry system and the signal from a hot-wire anemometry probe for triggering purposes. This has allowed the rotating three-dimensional flow associated with the precessing vortex core to be characterized for the first time at different downstream sections. Regions of reversed mean tangential velocity have been identified while new insights into the basic structure of the reverse flow zone have been provided.
The Turbine Performance of Centrifugal Pumps: A Comparison of Prediction Methods
Authors: Williams A A
Published: February 2007

Standard centrifugal Dumps may be operated in reverse as water turbines, and for hydroelectric plums of less than 100 kW (micro- hydro) they are often cheaper than specifically designed turbines. However, in order to use a pump in a micro-hydro scheme, the turbine performance-must be found either by testing or by calculation. Several methods have been suggested for predicting the turbine performance based on the data for pump performance at best efficiency, but they produce a wide range of results.

In this paper, eight such methods are compared using an analysis of the effects of poor turbine prediction on the operation of a pump as turbine at a typical micro hydro site. The comparison uses the results of turbine tests on 35 pumps of various types and sizes, some of which have come from the author's own tests. None of the eight methods gives an accurate prediction for all of the pumps but one of the methods can be recommended as a first estimate of the turbine performance.
Characteristics of a Power Station Boiler
Authors: O'Doherty T , Froud D , Bates C J , Syred N
Published: February 2007

An experimental investigation of the flow patterns in a model of a power station boiler has been carried out under isothermal conditions, to produce data for computational fluid dynamic code validation. Measurements were made in three dimensions on a single swirl burner in isolation, in two dimensions on a bank of 12 burners in a 4 × 3 grid and in the model boiler with this bank installed. The single burner exhibited a central reverse flow zone with high levels of turbulence at its boundaries. The general flow pattern found in the single burner was greatly distorted when interaction with surrounding burners in the bank occurred. Several unexpected secondary flows occurred. The model boiler displayed a complex flow arrangement with recirculation zones and two stagnation points.
The Long-Term Properties of Concrete Used in Prestressed Concrete Pressure Vessels
Authors: Bamforth P B , Price W F
Published: February 2007

Data are presented on the late-life properties of concretes used in prestressed concrete pressure vessels (PCPV) and containment structures. The effects of ageing under simulated PCPV conditions are discussed.
Sir Charles Parsons and Electrical Power Generation—a Turbine Designer's Perspective
Authors: Bolter J R
Published: February 2007

Sir Charles Parsons died some three years after the author was born. In this paper the author looks back at the pioneering work of Parsons in the field of power generation. It shows how he was able to increase output of the steam turbine generator from 7.5 kW in 1884 to 50000 kW in 1930 while increasing efficiency from 1.6 to 36 per cent, and relates these achievements to the current state of the art.

Blading design, rotor construction and other aspects of turbine engineering are considered. The conclusion is that Parsons and his associates charted the course which manufacturers and utilities throughout the world have continued to follow, although increasingly sophisticated design and analytical methods have succeeded the intuitive approach of Parsons. His constant search for improved efficiency was and is highly relevant to today's concern for the environment.

Finally, although it did not become a practical proposition in his lifetime, the paper reviews Parsons' vision of, and continuing interest in, the gas turbine, first mentioned in his 1884 patents.
Design and Performance of Vaneless Volutes for Radial Inflow Turbines: Part 1: Non-Dimensional Conceptual Design Considerations
Authors: Whitfield A , Noor A B Mohd
Published: February 2007

The requirements for the volute of a radial inflow turbine are that it should collect the working fluid, deliver it to the turbine rotor as efficiently as possible and provide the desired rotor inlet conditions. The design requirements of the turbine leads to the rotor design and the identification of the desired flow conditions at rotor inlet in terms of the magnitude and direction of the absolute Mach number. The volute must then be designed to ensure that the desired rotor inlet conditions are attained.

A non-dimensional design procedure for a vaneless turbine volute is described. Based on a knowledge of the flow direction and magnitude of the absolute Mach number at rotor inlet the overall dimensions of the volute in terms of the radius ratio and flow area ratio are first established. The overall design is then developed to provide the variation of the volute centroid radius and area ratio with azimuth angle. A trapezoidal cross-sectional shape is then used to establish the outer dimensions of the volute.

The non-dimensional procedure assumes a one-dimensional compressible flow and as such relies on the empirical specification of the dissipation of angular momentum, the dissipation of energy and the deviation of the swirling flow from that of a free vortex. The effect of the uncertainties associated with the empirical data on the volute design geometry is assessed.

A complementary experimental investigation to develop and substantiate the required empiricism is presented in Part 2, which follows. As the design procedure is essentially one-dimensional it must be interpreted with a knowledge of the actual three-dimensional flow within a volute passage. Supportive experimental studies will be presented in Part 3 in the next issue.
A Three-Dimensional Numerical Model of a Waste Incinerator
Authors: May H-O
Published: February 2007

A three-dimensional simulation model of the secondary combustion chamber of a waste incineration plant is presented. The model is based on a set of partial differential equations governing the transport of mass, momentum and energy, together with additional equations modelling the turbulence, heat generation by reaction and radiative heat-transfer phenomena. Because it was not possible to resolve the burner region by a grid being fine enough to describe all details and to get a grid-independent solution, profile measurements were made in a pilot-scale combustion chamber using an isotypical liquid injection burner. These results were used in order to find the parameters of the whole simulation. In order to verify the simulation model some results are compared with measurements of temperature and residence-time distribution at a real incineration plant, and two models are given for the description of the burnout behaviour. Finally the non-isothermal model is discussed and a comparison is made between the isothermal model and the non-isothermal model.
A Consultative Expert System for Fault Diagnosis of Turbine-Generator Plant
Authors: Gemmell B D , McDonald J R , Stewart R W , Brooke R N T , Weir B J
Published: February 2007

Turbine specialists have extensive experience in the analysis and interpretation of turbine–generator operational plant data and in the diagnosis of fault conditions. Expert system technology makes it possible for such expertise, elicited from specialists, to be structured in a ‘knowledge base’. This paper will discuss the application of specialist knowledge to the analysis of turbine–generator plant data to aid turbine staff of optimize plant performance, thus demonstrating to users the operation and potential benefits of a consultative expert system.
Use of Neutral Networks for on-Line Vibration Monitoring
Authors: Mayes I W
Published: February 2007

Some of the problems involved with monitoring the variable vibration behaviour observed on large turbine generators are described. The uses of neural networks are discussed and an alternative to the more commonly used network is proposed which has a significantly shorter training time. Examples are given of the use of these techniques for studying an oil whirl problem, an intertum fault, and reactive load dependent behaviour.
Modelling Spatial Radiative Heat Flux Distribution in a Direct Injection Diesel Engine
Authors: Cheung C S , Leung C W , Leung T P
Published: February 2007

In this paper, the spatial distribution of radiative heat flux from a luminous flame to various positions on the cylinder head of a direct injection diesel engine is modelled and the results compared with some published experimental investigations. The model is primarily based on measured pressure data, which are converted into fuel-burned rate data through a single-zone heat-release rate analysis. Coupled with appropriate soot formation and oxidation models, the fuel-burned rate data are converted into the soot contents in the cylinder. By separating the combustion chamber into a burned zone and an unburned zone, the radiation temperature, the absorption coefficient and the spatial distribution of radiative heat flux to the cylinder walls are calculated.
Business Systems Engineering
Authors: Turner F
Published: February 2007

Giving examples from Lucas, the paper outlines the route to simplifying operations and achieving the necessary step change in performance by understanding and applying ‘business systems engineering’ to the whole business process. Each part of the process is designed by finding the way that is most appropriate to meet the market requirements.
The Effects of a High-Pressure Coolant Jet on Machining
Authors: Machado A R , Wallbank J
Published: February 2007

A high-pressure coolant system was used to machine Ti6Al4V and Inconel 901. A 14.5 MPajet of cutting fluid was applied against the chip flow at the rake face of the tool and this works as an efficient chip-breaker. Conventional overhead flood cooling was also used to establish a base for comparison. Chip control, cutting force, cutting temperature, chip-tool contact length, surface integrity, tool lives and wear mechanisms were studied. The high-pressure coolant system used improved tool lives significantly when machining the titanium alloy but it proved to be detrimental to tool lives when machining the nickel alloy.
Knowledge-Based Approaches to Fault Diagnosis: A Practical Evaluation of the Relative Merits of Deep and Shallow Knowledge
Authors: Doherty N F , Kochhar A K , Main R
Published: February 2007

This paper argues that knowledge-based systems are an appropriate tool for the diagnosis of faults in complex devices and that both deep and shallow knowledge have their part to play in this process. The successful implementation and evaluation of the two diagnostic knowledge-based systems, named DIPLOMA and MIDAS, have shown that such systems are an appropriate tool for the diagnosis of faults in complex hydromechanical devices and that they make a beneficial contribution to the business performance of the host organization. Furthermore, it has been demonstrated that the most effective and comprehensive knowledge-based approach to fault diagnosis is one that incorporates both deep and shallow knowledge, so that the distinctive advantages of each can be realized in a single application.
A Probabilistic Approach to Performance Forecasting for FMS as Part of an Automated Factory
Authors: Cherpakov B I , Yukhimov V V
Published: February 2007

Specific features of a machining FMS operation in a complex production environment (a machine shop or an automated factory) are considered. A probabilistic approach to FMS performance estimation, ensuring a steady production rhythm of an automated assembly factory, is suggested. A probabilistic description of FMS performance estimation based on the concept of production potential and its respective probability of achieving the goal value with due account of the reliability of FMS production facilities and various organization factors is given. A complex optimality criterion of FMS production potential in an FA environment is described. A method of machining FMS production tasks planning in terms of time and volume of output is suggested. Application of the suggested method is illustrated by the example of designing a machine-tool automated factory.
Aspects of Wear Prediction in Precision Forging
Authors: Doege E , Nägele H , Schliephake U
Published: February 2007

Precision forging is a rather new special hot forming technology with a high economic potential. The lifetime of a forging tool is one of the most decisive factors during the economical evaluation of a forging and is therefore the subject of intensive investigation and research work. This paper shows results obtained in experimental work and theoretical analysis for the determination of tool wear. Observations have shown that the temperature of the raw material is of major importance for tool wear because of damaging effects on crystalline structure and in consequence mechanical properties of boundary layers of the forging tool. The example of temperature calculation which is strongly connected with heat exchange inside the tribological system explains the complex problems of the theoretical analysis. Additionally the heat transfer itself influences the geometry of the finished forged part, which is in the industrial case of major importance. The heat transfer during the different manufacturing stages has been analysed using the finite element method, which has been further developed to automatically determine the heat-transfer coefficient. Finally, a new method to calculate wear amounts at critical areas of forging tools is presented.
Ultrasonic Bubble Nucleation in Reaction Injection Moulding of Polyurethane
Authors: Cho W J , Park H , Youn J R
Published: February 2007

Ultrasonic foam processing of polyurethane for reaction injection moulding (RIM) was studied experimentally to investigate feasibility of ultrasonic bubble nucleation in polyurethane. Bubble nucleation was also studied theoretically to predict the rate of nucleation. Classical nucleation theory and cluster theory have been employed for explanation of the nucleation phenomena. A polyol resin was saturated with nitrogen at various pressures and the pressure was released slowly in order to generate supersaturated resin. Other components of the selected polyurethane system were added to the supersaturated resin and ultrasonic disruption was applied to the system producing enhanced nucleation. The ultrasonic excitation created a good foam structure even at a low saturation pressure around 0.15 MPa (1.5 atm). The effect of the ultrasonic activation on the bubble nucleation was considered and included in the nucleation theories. The cluster nucleation theory along with consideration of the ultrasonic effect predicted a higher rate of nucleation than the classical nucleation theory for the same condition.
Positional Accuracy of Holes When Drilling in Inclined Workpiece Surfaces Part 1: Experimental Results
Authors: Kaminski J , Crafoord R
Published: February 2007

The influence of cutting forces on hole positional deviation when drilling with twist drills in workpiece surfaces of 5° inclination and horizontal surfaces has been investigated. An approach to explain the drill tip wandering phenomena is presented.

Variations in cutting forces were also investigated when drilling in workpieces of different materials and different feedrates with standard as well as short drills. Results of this investigation show that hole positional deviation has an obvious connection to cutting forces. The standard and the short drills show different wandering paths during the penetration process. Standard drills wander down the slope, while the short ones first move downwards and later begin a motion upwards.
Positional Accuracy of Holes When Drilling in Inclined Workpiece Surfaces Part 2: Mathematical Force Model
Authors: Kaminski J , Crafoord R
Published: February 2007

In this paper, a drill wandering mechanism when drilling in inclined workpieces is described. A mathematical model for calculation of chip areas on the chisel edge and the lips has been developed and implemented by a computer. Simulations of the forces that occur on the contact areas between the drill tip and the workpiece are presented and discussed. A mathematical model for calculation of the resultant drill deflection, deviations in the drill axis of rotation and the position of its centre point as the drill penetrates the material is also proposed.
An Expert System for Concurrent Product and Process Design of Mechanical Parts
Authors: Abdalla H S , Knight J
Published: February 2007

A new approach for concurrent product and process design of mechanical parts is presented in this paper. This approach enables designers to ensure that the product will be manufactured with the existing manufacturing facility at high quality and lowest cost. It is composed of an integrated expert and CAD (computer aided design) system that meets the requirements for accomplishing the concept of design for manufacturability or concurrent engineering. The system is based mainly on three tasks: firstly, developing a technique for automated feature recognition from the database of a solid modeller; secondly, interfacing the expert system tool-kit with the solid modelling system; finally, building an expert system that contains extensive information about both manufacturing facilities and product features. The expert system provides feedback about manufacturing concerns such as process limits or design inconsistencies. This work is part of the present extended research plan for developing a generic system suitable for various manufacturing practices based on design for manufacturability strategy.
Sensor-Integrated Grinding Balls for on-Line Load Distribution Measurement in Ball Mills
Authors: Gao R X , Thelen W
Published: February 2007

For the on-line measurement of stress and energy distributions inside ball mills, two types of self-contained, autonomous grinding balls with fully integrated piezo-electric sensors and data-processing electronics are developed and fabricated. The basic model is designed for batchwise experiments on ball mills, where data registered in electronic memories are read out through cable connections to a processing circuit. The improved model contains additional data modulation circuits with a VHF microtransmitter, allowing on-line data retrieval. For the purpose of circuit miniaturization, hybrid and surface mount techniques (SMT) have been utilized. The instrumented balls are identical in size, mass and surface characteristics to the normal grinding balls, with the minimum outer diameter being 40 mm. Systematic experiments have shown that they are fully applicable in a realistic grinding environment where grinding media are presented. In addition to ball mill applications, the developed integration and measuring technique is generally suited for on-line data registration on free-moving objects or other industrial applications where accessibility of the measurand is insufficient.
A Generalized Approach to the Modelling of Modular Machines
Authors: Yan X T , Case K , Weston R H
Published: February 2007

This paper describes a method of graphically simulating modular machines within a computer aided design environment. This forms part of a much larger Science and Engineering Research Council (SERC) funded programme aimed at advancing modern practices when designing and building manufacturing machines.

A generalized approach to the synthesis of the generic features of various kinematic motion pairs is presented and prismatic and revolute motion primitives generalized in their functional and geometric aspects. A hierarchical ring and tree data structure has been designed and implemented to comprehensively represent these motion pairs and to simulate their performance. More complex modular manufacturing machines can be represented using information from a library of up to three degree of freedom motion modules. Seven two degree of freedom motion primitives and twelve three degree of freedom motion primitives with articulation configurations have been analysed and included in the motion primitive library. The configuration of modular machines comprised of physically separate but logically connected distributed motion primitives are described. Examples of a two-finger industrial robot gripper and a three-finger industrial robot hand are used to demonstrate the general principles.
An Annotated List of Design Principles
Authors: French M J
Published: February 2007

Recurrent types of problem in design lead to elegant solutions in which the operation of consistent design principles may often be traced. While some of these principles are given in the literature, many may not have been formally stated before. This paper lists those known to the author in a simple classified arrangement, and gives brief examples of their application and notes on their meaning and scope.
The Effects of the Damping Characteristics of Slideways on the Dynamic Characteristics of Workpiece Fixtures Mounted on Machine Tool Tables
Authors: Kobayashi T , Burdekin M
Published: February 2007

Not only dynamic characteristics of machine tool structures but also those of workpiece fixtures are important in machine tools as they directly influence the dynamic rigidity at a cutting point. In this paper, the effects of damping characteristics of slideways on the dynamic characteristics of workpiece fixtures mounted on machine tool tables have been clarified both theoretically and experimentally. Furthermore, a design criterion of workpiece fixtures has been suggested.
Quality Improvement in Research and Development: A Study
Authors: Lamb G E , Dale B G
Published: February 2007

The paper examines the current ideas and practices of the quality improvement process in three case studies carried out in different research and development (R and D) departments. The findings suggest that quality improvement is applicable to research and development as it is to any other type of function or activity; however, not all the quality management tools and techniques are suitable to R and D. It was found that top management leadership and commitment was just as important in the quality improvement process of an R and D department as it is in any other function. The main failure of top management to fulfil their leadership and visible commitment role appears to be due to a lack of understanding of how to apply the process of continuous improvement to R and D activities. Another point of confusion was the identification of the products of R and D and from this piece of research it is concluded that they are intangible products such as information. It is also pointed out that the internal customer concept is equally important to the R and D function as in other parts of the organization.