bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of Characteristic Pattern Methodology to the Design of Reheat Furnace Multi-Variable Control Systems
Authors: Ting I H , Gough N E , Dimirovski G M , Deskov V P
Published: February 2007

Characteristic pattern methodology, a multi-variable control system design technique based on discrete convolution algebra, is applied to the design of a candidate computer control scheme for a steel mill reheat furnace. Time domain process input-output data are used as the basis for the process model. A robust control scheme is designed, and its performance is compared with that of a traditional decentralized three-term controller, using CBSL, a multi-variable control systems design package.
Design of Autopilots for High Performance Missiles
Authors: Bradshaw A , Counsell J M
Published: February 2007

A novel control algorithm involving a robust inverse dynamics estimation (RIDE) is presented. It is shown how the control algorithm can be used in conjunction with a new safe criterion to result in the optimal and safe control algorithm (OSCA). The OSCA control algorithm is applied to the control of a high performance missile, where it is shown to provide excellent performance in terms of tight non-interacting and safe control in the presence of actuator saturation.
Design of Robust Two-Degree-of-Freedom Controllers for Position Servos Using H-Infinity Theory
Authors: Piché R , Pohjolainen S , Virvalo T
Published: February 2007

Linear feedback controllers for position servos are designed using the structured singular value optimization (Doyle's μ-synthesis) method. The method produces a two-degree-of-freedom controller, including both the feedback and the prefilter, which is ‘performance robust’, in the sense that the closed-loop system is guaranteed to meet performance specifications in the presence of unmodelled dynamics. A detailed design of a low-order controller for a hydraulic position servo, including numerical non-linear simulation results, is presented.
Technique for Deriving a Reduced-Order Formulation for Non-Conservative Mechanicalc Systems
Authors: Atadan S
Published: February 2007

An explicit reduced-order formulation is derived for non-conservative mechanical systems with external excitation. Reduction is facilitated by selecting a particular set of variables. The formulation is obtained by introducing a technique based on topological principles, involving the so-called M- and K-normal graphs.
Implementation of Minimal Control Synthesis on a Servo-Hydraulic Testing Machine
Authors: Stoten D P
Published: February 2007

The minimal control synthesis (MCS) algorithm is an adaptive controller that requires no prior knowledge of plant dynamic parameters, and yet is guaranteed to provide global asymptotic stability of the closed-loop system. The algorithm has been implemented on a variety of plant, ranging from laboratory-based rigs to industrial machines.

The purpose of this technical note is to present the results of the first known implementation of the algorithm on a servo-hydraulically actuated machine. The results of the MCS implementation will be seen to compare very favourably with those of a conventional (P + I) implementation.
Predictive Sliding Control with Fuzzy Logic for Fuel-Injected Automotive Engines
Authors: Nam S-K , Lee M-H , Yoo W-S
Published: February 2007

An alternative algorithm is proposed far a variable-structure control to design a closed-loop fuel-injection system. Sliding control using fuzzy logic is combined with current oxygen sensors to maintain the stoichiometric air/fuel ratio. Predictive control is also introduced to compensate for the lime delay in the combustion process. This synthesis provides a practical and flexible design for an engine controller because its hybrid structure meets given robustness and performance requirements. The potential of the proposed algorithm is shown through real-time simulations utilizing both a typical engine-only model on an AD-100 computer and an implemented controller on an Intel 80C186 with an 80C187 processor.
Swing-up Control of Inverted Pendulum Using Pseudo-State Feedback
Authors: Furuta K , Yamakita M , Kobayashi S
Published: February 2007

Swing-up control, that is the transfer of a pendulum from a pendant state to the inverted one, is a good laboratory experiment of optimal control theory for non-linear control systems. The optimal control can be determined by the maximum principle and obtained as a function of time. Since the control is, however, determined in a feedforward fashion, the control is not robust to disturbances and uncertainties of the system, and the transfer of the state of the pendulum is not assured. In the paper, a robust swing-up control using a subspace projected from the whole state space is proposed. Based on the projected state space or pseudo-state, the control input is determined depending on the partitioning of the state as a bang-bang type control. The control algorithm is applied for a new type of pendulum (TI Tech pendulum), and the effectiveness and robustness of the proposed control are examined by experiments.
The Design and Development of Modern Lifeboats
Authors: Hudson F D , Hicks I A , Cripps R M
Published: February 2007

Well-established operational practices have determined the evolution of RNLI lifeboats throughout their history. The RNLI's requirement/or an all-fast offshore fleet of the self-righting type by 1993, however, motivated the need to re-examine basic design parameters of boats and launching equipment. More recent requirements to improve lifeboat performance further have demanded even closer evaluation of design requirements of hull form, machinery installation and construction materials.

This paper outlines the history of the development of RNLI craft and describes the procedures for the design and development of its newest classes of lifeboat (FAB 3 and FAB 4), for which extensive model testing of differing hull forms was evaluated, various types of machinery were reviewed and construction, although in composite materials, was carefully designed to accommodate high hydrodynamic and impact loads.

Technical trials and operational evaluation procedures are also discussed.
The Radial Equilibrium Problem of Flow in Wave Machinery
Authors: Liu Gao-Lian
Published: February 2007

The present paper deals with the radial equilibrium problem of gas flow at the inlet and outlet of a wave rotor theoretically, presenting a method of solution. The salient feature of this method is that, in contrast to turbomachinery, the outlet flow parameters are related to those at inlet by the state characteristic (compatibility) equations of unsteady rotor flow. The numerical example has shown that the radial equilibrium effect plays a very important role in the design and performance of wave machinery and hence it is suggested that a complete gas dynamic design procedure of a wave machine should include two parts: (a) solution of the one-dimensional unsteady relative flow in rotor at the mean radius; (b) solution of the radial equilibrium problem of gas flow at the rotor inlet and outlet.
Review: Burning Refuse-Derived Fuel in a Rotary Cement Kiln
Authors: Lockwood F C , Ou J J
Published: February 2007

In cement kilns, combustion takes place under very high flame temperatures and relatively long residence times. These conditions are favourable for the burning of refuse waste. The purpose of this note is to review the combustion and pollutant emission implications of using such a fuel as a supplementary source of heat in a cement kiln.

Based on technical and environmental considerations, the analysis of burning refuse-derived fuel (RDF) in a cement kiln shows that no special firing technology has to be installed except that of the RDF handling system, that there is an upper limit to the total fuel consumption (no more than 30 per cent) for firing RDF and that there is no increase in the emission levels of air pollutants (including acid gases, dioxins, furans, etc.). At present, there seems to be no economical advantage in burning RDF. However, if municipal solid waste (MSW) is generated in large amounts and financial support is provided by the local authority to cover the investment/operating costs, burning RDF in cement kilns will become economically attractive as well as feasible.
A Simple Mathematical Model of Metal Hydride Elements for Thermal Powered Plants
Authors: Liventsov V M , Kuznetsov A V
Published: February 2007

This paper proposes a model for metal hydride elements which are used as hydrogen accumulators for different types of thermal powered systems. The quasi-stationary method has been used to obtain a simplified mathematical model. Calculations to predict the dynamic response of a thermal energy engine have been made.
The Potential of ‘Biodiesel’ from Oilseed Rape
Authors: Culshaw F A
Published: February 2007

This paper investigates the potential of biodiesel made from rapeseed oil as a transport fuel in the United Kingdom with respect to its economics, technology and environmental implications.
Integral Testing of the AP600 Passive Emergency Core Cooling Systems
Authors: Hochreiter L E , Fanto S V , Conway L E , Lau L K
Published: February 2007

In support of the development of AP600, Westinghouse is conducting two integral systems tests to examine the performance of the passive safety systems. A full-height, full-pressure test is being performed to simulate a small loss-of-coolant, steam generator tube rupture and large steam line break events. A one-quarter scale, low-pressure test is being performed to simulate transients with emphasis on the transition to the natural circulation post-accident, long-term cooling mode and to demonstrate the long-term cooling capability. Each of the tests will provide detailed experimental results for verification of the accident analysis computer codes.
Present State of Nuclear Fusion Research and Prospects for the Future
Authors: Keen B E , Watkins M L
Published: February 2007

This paper traces the development of nuclear fusion research and describes the basic principles involved. The most advanced device used to achieve controlled thermonuclear fusion is the magnetic confinement approach, utilizing the tokamak concept. The Joint European Torus (JET) is the largest tokamak in operation. The operating conditions are described and critical issues outlined. With concerted effort and international collaboration the possibility exists to produce a demonstration reactor.
Laminate Tooling for Injection Moulding
Authors: Glozer G R , Brevick J R
Published: February 2007

The main goal of this research was to develop a method of prototyping injection moulded parts which produces a representation of the production part, including not only the part shape and functionality but the process as well. A prototyping method that meets all of these requirements could greatly aid in reducing the time required to bring a new product to the market by using the information gained from this prototype to manufacture a production tool that will be right the first time. Tooling constructed of laminations is appealing for prototyping or production because of the flexibility it affords in terms of rapidly altering mould geometry, gating or cooling passage design.

This report summarizes a ‘proof of concept’ project which took a selected part geometry through the entire laminate tool manufacturing process. This report is divided into five sections: (1) introduction to the prototyping process, (2) background of current prototyping processes and description of the laminate tooling method, (3) description of the geometry selected for this work and the manufacturing details, (4) evaluation of the performance of the laminate injection mould and (5) conclusions.
Application of Design-and-Technological Product Classification in Computer-Integrated Manufacture
Authors: Dukarskii S M , Gnedenko V G
Published: February 2007

Classification of technical and economical information (CTEI) in computer-integrated manufacture (CIM) ensures an exchange of external and internal information, grouping of objects (articles, products, tools, etc.) according to the similarity of their essential features and their systematization, specialization and co-ordination of work of all parts of the CIM, analytical activity and recognition of products. The product design and technology classifier (DTC) plays an important role in the CTEI system because its application makes an impact on all stages of the product life cycle, from marketing to withdrawal and from operation and part utilization. This paper presents a systematized list of requirements to the CTEI as an object of CIM dataware and a list of problems that are caused by these requirements. The automated design-and-technological classification system (ADTCS) built at the I. V. Kurchatov Institute of Atomic Energy is an example of how the above problems can be solved. The article gives a description of the computer ADTCS and defines its applications in CIM.
A Philosophy of Linking Manufacture to Function— An Example in Optics
Authors: Whitehouse D J
Published: February 2007

It is well known that characteristics of a surface can be used to monitor the manufacturing process. It is also well known that the surface of a component is important, in many cases, in determining how well the component performs. Ideally, the manufacturing process should be picked to ensure that the part works satisfactorily. In this paper, as an example, the specific function of gloss is chosen as a requirement. It is then shown what sort of surface is most suitable for this and further how this surface should be made, thereby completing the chain from manufacture to function.
The Integration of Coordinate Measuring Machines within a Design and Manufacturing Environment
Authors: Medland A J , Mullineux G , Butler C , Jones B E
Published: February 2007

The role of the coordinate measuring machine within the inspection process has changed throughout its brief development. With its integration with industrial computer aided design (CAD) systems, its role is to change yet again. This paper presents the difficulties and limitations of current practice and identifies the inputs and decisions that need to be made within an integrated manufacturing environment.

A research programme was undertaken to investigate an approach based upon intelligent communications between systems. This led to the creation of a demonstration system that was employed in the measurement of industrial components. A case study, using a standard test block, is included to illustrate the processes undertaken. This includes feature identification, probe calibration and selection strategies and automatic re-routing to minimize changes in probes and orientations.

It is proposed that the approach demonstrated can be incorporated within a concurrent engineering environment to provide feedback and information about machine adjustments through a constraint modelling process.
From the Islands of Automation to the Knowledge Archipelago: The Challenge for Manufacturing Strategy in the 1990s
Authors: Brandon J A
Published: February 2007

The paper examines the complementary issues of the availability of novel technological ideas and the receptiveness of managerial infrastructure. It suggests that the apparently conflicting philosophies of the technological minimalists, who seek to restore manufacturing effectiveness by empowerment of work groups, and those who advocate large-scale automation of manufacturing systems in cellular form can be reconciled using ideas from object-oriented programming system.
The Use of a Machine Vision System in a Flexible Manufacturing Cell Incorporating an Automated Coordinate Measuring Machine
Authors: Wang X J , Butler C
Published: February 2007

The aim of this paper is to present a practical approach to the solution of problems associated with using an automated coordinate measuring machine (CMM) in a flexible manufacturing system (FMS) environment. The approach described uses machine vision and image processing techniques to permit transformations of the coordinate systems. In order to achieve flexible inspection, the system can recognize different workpieces by a quick matching method. The actual measuring path for the workpiece is derived from the original measuring path templates to allow for a workpiece to be measured in an arbitrary orientation on the table of the CMM. The original measuring path can be generated off-line by self-teach programming or from a computer aided design (CAD) system. The generation of the actual measuring path of the CMM is not limited by the complexity of the original off-line measuring path.
The Make or Buy Decision in the Context of Manufacturing Strategy Development
Authors: Probert D R , Jones S W , Gregory M J
Published: February 2007

This paper describes an approach to structuring the make or buy decision process, basing it firmly in the context of an overall manufacturing strategy. The work has been carried out jointly by the University of Cambridge Manufacturing Engineering Group and Lucas Industries. A review of the current state of ideas surrounding the linked issues of vertical integration and make or buy decisions is presented. Important features of the approach include identification of core manufacturing capabilities, assessment of the role of technology in manufacturing, the development of a cost model to support make or buy decisions and a review of the strategic implications of varying degrees of vertical integration.

Further, the approach has been embodied in a practical methodology that has been applied within Lucas Aerospace. A brief review of this practical application is included.
Layout Design of Large Made-To-Order Products Using a Knowledge-Based System
Authors: Hills W , Barlow M , Cleland G
Published: February 2007

Work is described which is concerned with the application of knowledge-based and emergent-order programming techniques to conceptual layout problems in the field of large made-to-order products. The aim of this work has been to develop a prototype for computer aided design (CAD) tools that manipulate and analyse a product's topology, rather than its precise geometry.

Features of the system include: working prototypes of a generic layout-oriented product model database schema and a layout design process. A knowledge-based system is used to advise the designer on optimal layout strategies and then, after layouts have been generated, to provide advice and assistance in the selection of the final layout.
Machine Vision Analysis of Welding Region and its Application to Seam Tracking in Arc Welding
Authors: Li Y , Middle J E
Published: February 2007

Unlike the application of machine vision in many other fields, there is a particular problem in developing machine vision for automated and robotic welding processes, because the disturbance of the arc light deteriorates the field to be viewed. This paper describes an analysis of the radiated energy from the weld pool, and based on this describes how vision sensing of the welding region may be improved.

An approach using specified pattern parameters is described to evaluate the ability to recognize an acquired image under different conditions such as with vidicons or sensor devices, different welding variables and optical parameters. Based on analysis of radiation from the welding region, a satisfactory wavelength range for sensing the image of the weld region is proposed and proved by experimentation. Images of gas tungsten arc welding (GTAW) and gas metal arc welding (GMAW) regions have been modelled and successfully implemented for seam tracking control with a simultaneously developed low-cost vision system.
On the Detectability of Roller Bearing Damage by Frequency Analysis
Authors: Su Y-T , Sheen Y-T
Published: February 2007

This study investigates the detectability of roller bearing damage by the frequency analysis of bearing vibrations. The magnitude characteristics of peaks in the vibration spectra are analysed. It is shown that the frequency information of vibration spectra for undamaged roller bearings can be the same as that for damaged ones. However, the magnitude information of vibration spectra for undamaged roller bearings is different from that for damaged ones. Thus, to detect the initial fault of roller bearing reliably, both the frequency information and magnitude information of vibration spectra have to be used.
Effect of Dehumidification of Air on the Performance of Eccentric Circular Fins
Authors: Kazeminejad H , Yaghoubi M A , Sepehri M
Published: February 2007

A theoretical analysis of the performance of cooling and dehumidifying an eccentric circular fin has been carried out. Numerical results for fin temperature distribution and fin efficiency were obtained for various ranges of psychometric conditions and compared with those of a dry fin. The effect of eccentricity on the fin efficiency was also investigated. It was found that the fin efficiency decreases as dehumidification or eccentricity is increased.
Anatomy of the Stirling Engine Cycle
Authors: Organ A J
Published: February 2007

Conditions are isolated for thermodynamic processes in two Stirling cycle machines to be identical. The conditions form the basis for the concept of ‘functional similarity’. Using the similarity conditions the designer may scale the detailed gas circuit specification of a viable Stirling engine to a derivative design of different size, crankshaft speed, working fluid and pressure. The method complements, and provides an independent check of, the simulation approach to gas circuit design.
Shape Sensitivity Formulation for Axisymmetric Thermal Conducting Solids
Authors: Lee Boo Youn
Published: February 2007

A direct differentiation method is presented for the shape design sensitivity analysis of axisymmetric thermal conducting solids. Based purely on the standard boundary integral equation (BIE) formulation, a new BIE is derived using the material derivative concept. Design derivatives in terms of shape change are directly calculated by solving the derived BIE. The present direct method has a computational advantage over the adjoint variable method, in the sense that it avoids the problem of solving for the adjoint system with the singular boundary condition. Numerical accuracy of the method is studied through three examples. The sensitivities by the present method are compared with analytic sensitivities for two problems of a hollow cylinder and a hollow sphere, and are then compared with those by finite differences for a thermal diffuser problem. As a practical application to numerical optimization, an optimal shape of the thermal diffuser to minimize the weight under a prescribed constraint is found by use of an optimization routine.
A Simplified Approach to Buckling of Plain C Channels under Pure Bending
Authors: Fok W C , Lu G , Seah L K
Published: February 2007

A study of the behaviour of C channel under pure bending applied in such a way as to create compressive stress at the tip of the webs is presented. The analysis encompasses the entire loading history of the beam, from the linear elastic stage, through the buckling of the webs, to the unloading stage after the formation of a plastic hinge. The theoretical predictions were compared to the test results of a series of seven beams. Close correlation was found between theory and experiment over the entire loading range explored, especially for sections with a width-thickness ratio of less than 50.
Efficient Modelling of Elastic Mechanisms Using Orthogonal Coordinates
Authors: Davison P , Longmore D K , Barrows C R
Published: February 2007

A systematic method is presented for deriving the equations of motion of mechanisms involving multiple elastic structures connected together by any form of driven or undriven joints. It is assumed that deformations within components are small but there is no restriction on joint motions. Orthogonal coordinates are used to decouple the linear, angular and elastic partitions. The deformation coordinates represent a finite number of the free modes of vibration of each component. Algebraic constraint equations are defined generally for common joints and any new constraints are automatically generated using symbolic techniques. The chosen coordinates and the method of formulating the equations allow efficient numerical solution.
Orbit Complexity: A New Criterion for Evaluating the Dynamic Quality of Rotor Systems
Authors: Qu Liangsheng , Shen Yudi
Published: February 2007

This paper introduces a new criterion called the index of orbit complexity (ICPX) to evaluate the dynamic quality of rotor systems during operation. This criterion originates from the singular spectra of the received signals and their spectra entropy. It can be used to evaluate the dynamic design quality of a rotor system. It is also useful in the condition monitoring of large-scale rotating machinery to monitor dynamic stability. Some examples from production practice are used to apply the criterion.
Asperity Deformation Models for Explaining the Mechanisms Involved in Metallic Sliding Friction and Wear—A Review
Authors: Black A J , Kopalinsky E M , Oxley P L B
Published: February 2007

Tabor (1) has given a physicist's view of research into the basic mechanisms of friction. In the same vein the present paper gives a review of the basic mechanisms of metallic sliding friction and wear from a mechanical engineering point of view. A review of the application of asperity deformation models in building up wear maps for metallic sliding wear which can usefully be read in conjunction with parts of the present review has been given by Childs (2).
A Study of White Smoke Generation and Its Numerical Simulation
Authors: Shiozaki T , Otani T , Joko I
Published: February 2007

A mechanism of white smoke generation is clarified by a visualization technique using high-speed photography. The adhered fuel spray on the wall of the cavity, the fuel in the lean mixture region, the spilled fuel from the combustion cavity and the fuel from the sac volume of the nozzle tip are converted to the white smoke late in the expansion stroke. Numerical simulation is also conducted and its results coincide well with experimental results.
A Numerical Method for Noise Optimization of Engine Structures
Authors: Milsted M G , Zhang T , Hall R A
Published: February 2007

A numerical procedure is described for optimizing finite element models of engine structures for minimum noise radiation. A statistical technique is used to select sample points in a multi-dimensional design variable space from which an approximating response surface is derived. Optimization of this analytic model is then carried out interactively with variable bounds and constraints as required to meet design objectives. The underlying noise analysis calculation uses a modal analysis algorithm to determine the surface vibration velocity and hence the radiated sound power. It incorporates a sophisticated procedure to determine the forces applied by the crank train to the cylinder block and head. Although computationally intensive, useful design studies are now practical using concept level finite element models.
Experiences and Trends in Human Resource Development
Authors: Bertodo R , Candela A
Published: February 2007

Organizational trends are polarizing away from hierarchical divisions of labour towards a more fluid deployment based on multi-skilled teams and competent individuals. It is demonstrated that there are measurable efficiency advantages to be gained from such a transition. The paper demonstrates the feasibility of accomplishing the reorganization, the difficulties met and the implementation strategies resorted to. It is concluded that organizational efficiency can be improved by one order of magnitude. No organization would seem to require more than two or three functions aligned to its main strategic processes.
Engineering for the Customer—Development and the Future
Authors: Wood J R
Published: February 2007

This Address highlights some of the facets of development engineering as experienced by the Chairman in his career in the Army, motor racing, RAC Motoring Services and MIRA. Examples are given of the evolution of test and development capabilities at MIRA to show how techniques have progressed.
On the Preview Control of Limited Bandwidth Vehicle Suspensions
Authors: Pilbeam C , Sharp R S
Published: February 2007

Using methods established in earlier work, calculations are carried out to determine the performance possibilities of a slow-active automobile suspension. The suspension consists of a limited bandwidth actuator in series with a passive spring, the combination being in parallel with a passive damper. Use of the correlation between the front and rear wheel inputs is made to determine near-optimal state feedback laws which improve on the uncorrelated (non-preview) laws found using standard linear quadratic regulator (LQR) theory. Various control laws are calculated for different vehicle speeds and the effects of placing the emphasis on either ride comfort or vehicle handling in the control law are studied. It is found that there is significant advantage to be gained in making use of the preview information available when the emphasis is placed on ride comfort in the cost function. Increasing the amount of preview (by reducing the vehicle speed) increases the amount of improvement made available by the use of preview information down to a speed of 10 m/s, below which there is nothing to be gained from having more preview. Due to the practical advantages associated with the use of limited bandwidth active control in comparison with full bandwidth systems and the small additional costs implied by adding to the signal processing required as specified, the results are considered important to the future development of active vehicle suspensions.
Mechanisms of Heat Transfer to Liquid Films in the Manifold of Port-Injected Petrol Engines
Authors: Ladommatos N
Published: February 2007

Results are presented from flow-rig tests in which water from an automotive engine injector was sprayed on to a small heated surface in the presence of both steady and pulsative air flow. The injection was intermittent and synchronized with the pulsating air flow. The aim of the tests was to improve understanding of some of the basic heat and mass transfer mechanisms that occur in port-injected sparkignition engines where fuel is usually sprayed on to the back of the inlet valve. The main observations focused on the heat transfer to the film and the entrainment of the spray and film by the air stream.
The Actual Use of the Dynamic Performances of Vehicles
Authors: Lechner D , Perrin C
Published: February 2007

INRETS (France) has carried out research work to determine to what extent drivers make use of the dynamic performances of vehicles in the course of everyday driving. A sample of drivers from varied backgrounds drove over a set distance, including all types of road infrastructures, at the wheel of a specially instrumented vehicle. The data analysis shows that longitudinal and lateral accelerations are low in everyday driving. Significant inter-individual variations in the behaviour of drivers, when at the wheel of the same vehicle, over the same stretch of road, were also revealed.
Vehicles that Skid over Embankments
Authors: Smith R , Beaumont H
Published: February 2007

Reconstruction of road accidents are increasingly being used in courts. Some accidents involve a vehicle skidding over an embankment. This paper derives approximate analytical expressions for the launch phase of such an accident. These, together with the equations for free fall, are then used to calculate the initial speed of the vehicle. The analysis assumes that the vehicle does not ground on the edge of the embankment. A simple test on the initial speed is developed to ensure that this assumption is not violated. Some numerical results are presented to illustrate the differences between this analysis and two other models. Extensions to the analysis are suggested.
On the Design of an Active Roll Control System for a Luxury Car
Authors: Sharp R S , Pan D
Published: February 2007

The handling responses of an actively suspended large car to ramp steering wheel inputs are calculated. The car is fitted with rotary actuators in the anti-roll bars at front and rear, operating under displacement control and stimulated by the output from a lateral acceleration sensor, constituting an active roll control system. The study is closely associated with an earlier one and the system model utilized is the same. New results are generated. They show the influences of changing the speed of response of the flow control valve and the sampling frequency of the digital control scheme. More complete energy consumption computations are reported. The results add significantly to those already published. The viability, in terms of performance capabilities, of roll control systems of this nature is confirmed and, taken together with the earlier results, the present work defines more closely the design needs of this type of system.
An Interlaminar Shear Test for Fibre-Reinforced Plastics
Authors: Sideridis E , Ashton J N , Kitching R
Published: February 2007

The measurement of the interlaminar shear strength of glass-reinforced plastic (GRP) laminates is proposed using an offset four-point bend test on a beam where two (P) of the four forces differ from the other two (Q) and the ratio λ = P/Q depends upon the relative positions along the beam. The paper describes the development of this test which appears simpler, more economic and more realistic in many aspects than other test methods. It is demonstrated theoretically and experimentally that the span length (L), thickness (t) and the ratio λ are important test parameters in determining whether the failure is by shear or by flexure. A test rig was designed and constructed to investigate the influence of these parameters and to determine the interlaminar shear strength of a GRP laminate. Specimens were made from polyester resin containing E-glass fibres in the form of chopped strand mat (CSM). Clear and repeatable interlaminar shear failures have been obtained where L/t was relatively small and Λ large. The crack formation mechanism was studied using photography.
The Application of Computer Techniques in the Design and Manufacturing of Timing Scrolls
Authors: Tang L Q , Moreton D N
Published: February 2007

The timing scroll is an important feeding mechanism on packaging lines. As packaging line speeds have increased and the shape of containers has become more diverse, the techniques used for the design and manufacture of such timing scrolls have become critical for successful packaging line performance. Since 1980, various techniques have evolved to improve scroll design, manufacture and the associated line performance. In recent years, as CAD (computer aided design), CAM (computer aided manufacture) and CNC (computer numerical control) techniques have evolved, scroll design and manufacturing techniques began to be linked with computer techniques. In this paper, a scroll design and manufacturing package is presented which can be run on a minicomputer, such as a μ-VAX on an IBM PC clone. This scroll package can produce a timing scroll for any type of container with a correct pocket shape and good dynamic characteristic. Tests using carefully chosen containers have been made using this package and the results indicate that the scrolls obtained by this package have the correct pocket shape and good line performance. However, the design of a good pick-up geometry for some container shapes remains a problem.
New Turbo Trains for the Chiltern Lines
Authors: Paling K D
Published: February 2007

The paper describes the evolution of the new Class 165 Network Turbo Diesel Multiple Units for the Chiltern Lines of Network SouthEast, from initial business requirement to emerging service experience. Development of the Turbo concept and Business Specification, including the extensive use of mock-ups and models, is described in detail. Translation of the Business Specification into a technical Procurement Specification and the procedures followed for the procurement of Turbos are explained.

The manufacture, testing, commissioning, and emerging service experience of Turbos are described. Reference is made to the further introduction of Turbos to Network SouthEast's Thames and West of England lines and a view is given of possible future developments.
The Evolution of Railway Research and Development at a Heavy Haul Railway
Authors: Marich S , Walker W
Published: February 2007

The economic value of research has been well demonstrated on the BHP Iron Ore heavy haul railroad. The research began when the considerable expansion that occurred soon after the start of operations led to accelerated component deterioration. This raised the possibility of having to curtail production. The paper describes how the nature and direction of the research activities have changed over time, with the programmes becoming more proactive rather than reactive.
The Role of Structured Reliability Studies in Locomotive Design
Authors: Harmsworth S L
Published: February 2007

This paper will illustrate how the rail transportation industry has benefited from the Electro-Motive Division (EMD) of General Motors Corporation adhering to a structured reliability process during the design of new locomotive models. This structured process continues throughout the life cycle of a locomotive to ensure that any potential product problems are detected and analysed and corrective action applied. Details will be provided on how the elements making up the EMD reliability process such as modelling, predictions, growth tests, verification tests and statistical analysis tools have actually been applied to development activities associated with new locomotives.
Mechanical Damage to Aircraft Structures from Lightning Strikes
Authors: Reid G W
Published: February 2007

The various types of current waveforms associated with lightning discharges are discussed together with their relevance to different areas of the aircraft structures.

The physical damage that could be sustained by aircraft material due to lightning strikes, in particular the damage to composite material especially carbon fibre, is described. This damage is primarily due to the very fast heating and impulsive forces which lightning currents can produce. Minimum cross-sectional areas required to carry these currents safely are discussed as well as the effect of moisture content and loading the samples during test for the case of carbon fibre composite material.

Details of the effects of arc attachment to various composite materials and also metal with the degree and type of damage that can be produced are reviewed.
The Use of Satellites for Aeronautical Communications, Navigation and Surveillance
Authors: Ferebee I C
Published: February 2007

Aeronautical communication and navigation using satellite systems are becoming viable alternatives to conventional VHF (very high frequency) and HF (high frequency) operation. These newer satellite-based systems result in enhanced coverage for oceanic regions. A history of the development of these satellite-based systems is presented. The combination of these systems into a global system to enhance air traffic control functions is proposed.
The Philosophy of Aircraft Warning Systems
Authors: Newman T P
Published: February 2007

This paper provides a summary of the current status of warning systems in commercial aircraft. The author reviews the events that may require pilot action during the flight of an aircraft and the effectiveness of particular warnings.
Aero Engine Ceramics—the Vision, the Reality and the Progress
Authors: Angus J P
Published: February 2007

Figure 1 shows ceramic exhaust nozzle petals and their application on a military engine. The ceramic material used is one of the most advanced materials in the world today. It consists of two-dimensional woven and laminated silicon carbide fibres in a chemical vapour infiltrated silicon carbide matrix.

In this application this material will eventually be expected to perform at 1200°C, 300°C hotter than today's cooled metal petals and last four times longer. To date the petals have been successfully interchanged with the existing metal petals, which run in a cooled environment on this engine. The Rolls–Royce target is to develop ceramics which operate up to 1400°C, which is 500°C hotter.

Before ceramic nozzle petals can enter service there are many difficult issues that must be addressed. One of these is the present long and very costly production route. This application illustrates the reality of applying ceramics to aero engines. It is one of the easier applications!

Why is it worth persevering with this difficult technology? The industry is a very competitive one. Ceramic materials offer the potential for significant performance improvements. They may in time create the competitive edge which means the difference between a growing or shrinking market share.
Ligament Forces at the Knee during Isometric Quadriceps Contractions
Authors: Zavatsky A B , O'Connor J J
Published: February 2007

A mathematical model of the knee in the sagittal plane was used to investigate the ligament forces resulting when a posteriorly directed external force, applied to the tibia, resists extension of the knee under increasing isometric quadriceps contractions. The model is based on simple geometric representations of the bones, ligaments and muscles at the knee.

An elementary mechanical analysis was used to predict which ligament, the anterior or posterior cruciate, was loaded at a given flexion angle and known line of action of the external force. Ligament force, as a proportion of the external force, was calculated first assuming the ligaments to be represented by single, inextensible lines. Modelling the ligaments as continuous arrays of extensible fibres then showed that tibio-femoral translations and ligament forces increased non-linearly with increasing muscle forces and approached asymptotic values which depended on flexion angle. In most positions of the joint, the calculated asymptotic ligament force values were less than the reported ultimate strength of human ligament, despite quadriceps forces of over three times body weight. The possibility of these asymptotic values of ligament force may explain why, at certain flexion angles, large forces can be developed by the muscles at the knee without ligament rupture.
Biomechanics of Sports and Sports Injuries
Authors: Smeathers J E , Wright V
Published: February 2007

This overview paper summarizes recent work on the biomechanics of sports activities, prevention and repair of sporting injuries with reports on the papers presented at the Eighteenth Annual Day Conference, held in Leeds on 8 January 1993, by the Bioengineering Group for the Study of Human Joints in association with the Biological Engineering Society.
Recommendations with Respect to the Improvement of Lubricating Qualities of Synovial Fluid in Artificial Joints
Authors: Gavrjushenko N S
Published: February 2007

This paper gives a short description of the lubricating properties of yellow and red bone marrow taken from a femur of a cadaver. The experiments have been conducted on a ‘ball-on-plate’ model. The balls were made from steel 100 CR6 (German) and the plates were made from the same steel and ultra-high molecular weight polyethylene (UHMWPE, German ‘Herulen’).

The friction coefficients under loads of 50 and 300 N were determined with different combinations of friction components.

It has been found that the lubricating properties of yellow and red marrow have advantages over synovial fluid. In the light of these results the author develops a new approach to the design of a new hip endoprosthesis.
Parametric Modelling of a Knee Joint Prosthesis
Authors: Khoo L P , Goh J C H , Chow S L
Published: February 2007

This paper presents an approach for the establishment of a parametric model of knee joint prosthesis. Four different sizes of a commercial prosthesis are used as an example in the study. A reverse engineering technique was employed to reconstruct the prosthesis on CATIA, a CAD (computer aided design) system. Parametric models were established as a result of the analysis. Using the parametric model established and the knee data obtained from a clinical study on 21 pairs of cadaveric Asian knees, the development of a prototype prosthesis that suits a patient with a very small knee joint is presented. However, it was found that modification to certain parameters may be inevitable due to the uniqueness of the Asian knee. An avenue for rapid modelling and eventually economical production of a customized knee joint prosthesis for patients is proposed and discussed.
An Isoelastic Prosthesis Using a New Composite Material
Authors: Taylor D , Martin C , Cornelis B , Jones M E B
Published: February 2007

A new particulate composite material has been assessed with regard to the design of an ‘isoelastic’ or ‘modulus matched’ hip prosthesis. Three different prototype designs were assessed, each of which consisted of a femoral component made from the composite material, attached to a metal ball via a metal ‘spike’ insert. The prototypes varied in terms of the detailed shape of the spike, which was modified in the light of photoelastic stress analysis, so as to produce a more acceptable stress distribution to the composite material in the proximal region.

Prototypes were made by hand moulding and by transfer moulding; both methods produced defects of various kinds. Simulation tests were conducted using a model of the proximal femur constructed from glass fibre composite, cyclically loaded in a servo-hydraulic testing machine. Though some difficulties were experienced with defective mouldings, especially for the transfer moulding process, a clear improvement was demonstrated for the final (Mark III) design. The fatigue endurance of this prototype was similar to that of conventional metal prostheses tested under similar conditions.

Fatigue crack propagation tests were carried out on samples of the composite material to establish its propagation threshold. These results were combined with a finite element stress analysis and fracture mechanics theory to estimate the critical crack length for fatigue in this prosthesis. It was thus possible to specify the maximum safe size of defect that could be tolerated in use.
Some Problems in Using a Polyvinylidene Fluoride Transducer for the Intra-Articular Determination of Joint Contact Stress
Authors: Hale J E , Vaughan C L
Published: February 2007

A piezoelectric transducer and associated instrumentation were developed and evaluated as a means of experimentally determining joint contact stress. Each transducer, fabricated from a polyvinylidene fluoride film, comprised four discrete sensing elements. Following dynamic calibration of all sensing elements, in vitro evaluations were performed with transducers positioned in canine tibio-femoral joints. Quantitative measurements of contact stress as a function of time were obtained using these transducers, the magnitudes of which ranged between 0.01 and 7.99 MPa. Limitations associated with the transducer material and its use in this specific application included calibration variability and temporal phase shift of the transducer output signal relative to the applied load.