bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neural Classifiers for Automated Visual Inspection
Authors: Pham D T , Bayro-Corrochano E J 
Published: February 2007

This paper discusses the application of a back-propagation multi-layer perceptron and a learning vector quantization network to the classification of defects in valve stem seals for car engines. Both networks were trained with vectors containing descriptive attributes of known flaws. These attribute vectors (‘signatures’) were extracted from images of the seals captured by an industrial vision system. The paper describes the hardware and techniques used and the results obtained.
Belt Torque Loss in a Steel V-Belt Continuously Variable Transmission
Authors: Micklem J D , Longmore D K , Burrows C R 
Published: February 2007

To achieve the potential advantages to be gained by the use of a high ratio range, continuously variable transmission (CVT) in an automobile it is important that the system has a high efficiency and that any inherent loss mechanisms are fully understood. This paper investigates the belt-related torque loss in a steel V-belt CVT. Measurements show that the loss is dependent on the secondary pulley clamping force and on the belt configuration and these results are presented in the paper. A semi-empirical model is proposed to explain the loss. The agreement between the measured results and the values calculated from the model is shown to be good. It is also shown that when the system is in an overdrive ratio and a high efficiency is particularly important the torque loss is large and the efficiency is severely limited, probably to less than 90 per cent.
Stresses in Storage Tanks Caused by Differential Settlement
Authors: Palmer S C 
Published: February 2007

Differential settlement around the circumference of the foundation below the shell of a vertical cylindrical storage tank is a particularly severe form of settlement, and can cause distortion and stressing of the tank. The resulting deflections and stresses in the shell and primary wind girder of a tank with a floating roof can be analysed, assuming the shell to behave as a membrane. The analysis is reviewed and the results are applied to present a new design chart for predicting the maximum shell membrane stress caused by settlement. For unanchored tanks, the stiffness of a tank may be such that the shell can ‘bridge’ across localized soft spots in the foundation. A simplified analysis of bridging is presented and a criterion for predicting the onset of bridging is proposed, supported by model test results. Expressions for the associated shell membrane stresses are derived. For unanchored floating-roof tanks, it is concluded that the occurrence of bridging will always limit the maximum shell membrane stress to an acceptable value. However, the bending stresses in the shell-to-base joint of a bridging tank require separate assessment in all cases. The settlement criteria contained in the current British and American codes of practice for in-service inspection of tanks are reviewed in the light of these findings.
Bogies, Suspensions and Ride Quality
Authors: Rollin D 
Published: February 2007

This paper discusses the commercial importance of ride quality to the InterCity traveller and describes current technical developments and their application. Options of improving ride quality of existing vehicles are outlined together with the developments in active suspensions which will be needed by the next generation of high-speed vehicles for operation on existing tracks. The author concludes by considering the likely impact on bogie and suspension specific specifications as a result of the separation of technical and commercial responsibility for track and trains currently underway in a number of European countries. For the business engineer, ride quality is a commercial requirement which must be translated into a performance specification. This immediately raises the question, ‘How can ride quality be defined so that engineering parameters reflect the perceptions and aspirations of the customer?’
Revitalization of Chadderton: The Evolution of a Modern Aerostructures Business
Authors: Wilson D 
Published: February 2007

Over the last five years, an exciting transformation has been taking place at British Aerospace's Chadderton facilities at Greengate, just inside the Oldham Borough boundary. A large and complex manufacturing organization has been transformed from a programme-driven cost centre to an autonomous business unit, operating within the British Aerospace corporate structure. Developments at the Chadderton plant are setting the pace in a fast-changing industry. A frank and honest evaluation of the competences and strengths has been essential, and this has led to the development of strategies to achieve world-class benchmark performance. The process has been a necessary evolution to catch up and overtake the competition; it has also been traumatic and exciting, and demonstrates the potential that exists in our traditional manufacturing businesses.
Thermohydrodynamic Analysis of Journal Bearings Lubricated by Non-Newtonian Fluids—Theory and Experiments
Authors: Sheeja O , Prabhu B S 
Published: February 2007

Viscosity index improvers cause the lubricants to exhibit non-Newtonian flow behaviour and display shear thinning and normal stress differences. Shear thinning behaviour is studied by using a rotary shear viscometer. Owing to the non-availability of a rheogoniometer (for the measurement of normal stress differences), the first normal stress difference is calculated from the viscometric data using the Carreau viscosity function. The influence of the first normal stress difference on the hydrodynamic lubrication is analysed and shows that most of the commercial oils are inelasticoviscous in nature. Regression analysis shows that a large number of commercial lubricants follow the inelasticoviscous cubic law fluid model. Hence the cubic law fluid model is considered for the theoretical analysis. An experimental programme is developed to measure the effect of test parameters on the performance of a journal bearing lubricated with different types of non-Newtonian fluids. The experiments mainly include the measurements of the steady state characteristics like film thickness and fluid film friction. The experimental film thickness values are compared with the respective theoretical ones and are in good agreement. The theoretical performance characteristics are obtained through the simultaneous solution of the modified Reynolds equation using the cubic law fluid model and energy equation. The fluid film friction in a hydrodynamic journal bearing is experimentally determined through coastdown analysis. The results are presented in the form of an apparent Stribeck diagram of friction and are compared with the respective theoretical values.
Modelling the Transient Behaviour of Heat Recovery Steam Generators
Authors: Dechamps P J 
Published: February 2007

This paper describes a method used to compute the transient performances of assisted circulation heat recovery steam generators. These heat recovery steam generators are composed of several heat exchangers, each of which is a bundle of tubes. The method presented here treats each heat exchanger in a similar way, replacing the bundle of tubes with an ‘equivalent’ linear heat exchanger. This equivalent linear heat exchanger is then discretized in as many slices as required by the accuracy. The mass and enthalpy equations on each of these control volumes are solved by a fully explicit numerical method, adapted for the special conditions encountered in this kind of problem, allowing a considerable reduction of the computation time compared to other methods. Some emphasis is put on the modifications required to solve the equations for the evaporators because they are two-phase heat exchangers. A model for the steam drums is also presented together with simple models for the main control loops used in such systems. An example is presented in which an existing dual pressure level heat recovery steam generator is started from a cold state. The numerical predictions are in good agreement with measurements.
Design and Performance of a Variable Valve Timing System on a Highly Turbocharged Diesel Engine—Experimental and Predicted Results
Authors: Stone C R , Leonard H J , Elliott C , Newman M J , Charlton S J , Johnston D N 
Published: February 2007

A previous study using a cycle simulation program had identified the possibility that highly rated diesel engines might benefit from a variable valve timing (VVT) system. In particular, the study had shown that, by delaying the start of inlet valve opening at part load, it should be possible to eliminate the reverse flow that can lead to inlet port fouling. The work reported here encompasses the design and implementation of a variable valve timing system on a highly rated high-speed marine diesel engine. The principal topics addressed are the selection and design of a mechanism, a comparison between the predictions and results from mechanism testing on a single-cylinder valve-train rig and the engine performance predictions and results obtained when the mechanism was tested on the engine. The results from the single-cylinder test rig demonstrated that the mechanism performed satisfactorily, and this led to a design suitable for retro-fitting to the engine. The engine was comprehensively instrumented and the experimental results were in good agreement with the cycle simulation predictions.
Design of Hydraulic Ram Pump Systems
Authors: Young B W 
Published: February 2007

Automatic hydraulic ram pumps are environmentally friendly devices using a renewable energy resource to pump water for domestic or agricultural use. Since being superseded by pumps using electrical or fossil fuel energy nearly a century ago, they are now coming back into favour in many parts of the developing world. In the past, hydraulic ram pumps have been designed by rules-of-thumb having limited scientific basis. On-site adjustment has been used in the hope of rectifying the inevitable shortcomings of this process and ideal performance is rarely achieved. The present proposal for optimum design allows relevant system parameters (including the beat frequency) to be selected prior to installation. The paper shows how a ram pump system may be designed using two simple equations containing empirical factors dependent upon ram size, delivery head, material and wall thickness of the drive pipe and the configuration of the impulse valve. The design method is illustrated with reference to a number of existing tests. New experimental results for a 53 mm ram with five different impulse valve strokes are also presented.
Secondary Flow in Repeating Stages of Axial Turbomachines
Authors: Horlock J H 
Published: February 2007

In a well-designed multi-stage axial flow compressor, the flow settles down to a repeating condition, in which the axial velocity profile does not deteriorate further; it is more or less unchanged between the entry and the exit of a deeply embedded stage. However, experimental data also show that the flow angles repeat, and it is this flow phenomenon that is discussed in the paper. Secondary flow analysis, coupled with empirical data on clearance flows, is used to give a description of the flow in such a repeating stage. The secondary flow at exit from a row involves both the streamwise vorticity generated in that row and the vorticity that exists at entry—the so-called ‘skew’ vorticity due to a non-uniform velocity from a stator being received by a moving rotor (and a similar effect from the rotor to the stator). However, clearance vorticity—shed from the rotor tip (casing) section and the stator root (hub) section—is also present and can be taken into account. Calculations made using the analyses are compared with some limited experimental data drawn from the published literature. Predicted underturning at rotor tip (casing) sections is confirmed by experiments; similarly, predicted underturning at stator tip (casing) sections accords with observations in one compressor but not in another. However, no universal conclusion (on whether underturning or overturning usually occurs) can be drawn for the flow through the rotor and stator root (hub) sections, as either entry or generated secondary vorticity may dominate.
A Study of the Residual Stress Reduction Method Through the Mechanical Loading Cycle in Metal-To-Ceramic Brazed Joints
Authors: Kim W-B , Na S-J 
Published: February 2007

The transient thermal and residual stresses in the metal-to-ceramic brazed joints were analysed by using the finite element method (FEM). The thermal and residual stresses which were induced mainly by the difference in the thermal expansion coefficients between the brazed materials were successively calculated. The high tensile residual stress occurred in the brazed joint interface, which has the potential to cause internal cracks in the brazed joints. In order to reduce the tensile residual stress in the brazed joint, the mechanical loading cycle was adopted during the brazing thermal cycle. The calculation results revealed that the tensile residual stress in the brazed ceramics can be reduced by the mechanical loading cycle and that the magnitude of the applied load and the temperature at which the mechanical loading cycle started greatly influence the reduction amount of the tensile residual stress. For a comparison of the simulation results, the residual stress in the brazed joints was measured by using the X-ray diffraction method. The results calculated by the FEM analysis showed a similar tendency to the results measured by the X-ray diffraction method. In the case of brazed joints with 0.1 mm thick filler metal, the residual stress in the ceramic part after the mechanical loading cycle showed a lower tensile stress compared to that of brazed joints without the mechanical loading cycle. The larger the applied load, the smaller was the tensile residual stress occurring in the metal-to-ceramic brazed joint.
Extended Formability Limits for Tubular Components Through Combined Injection Forming/Upsetting—A Finite Element Analysis
Authors: Petersen S B , Rodrigues J M C , Martins P A F 
Published: February 2007

In the injection forming/upsetting of tabular parts the ratio between inner and outer diameters of the tube, the ratio between wall thickness and gap height, together with the design of the die chamber are important dimensional parameters that determine the final geometry of a component. Recent published work in this field opened a breakthrough in the understanding of the limits for obtaining sound components without folds. However, some difficulties were still encountered, namely in what concerns avoiding the presence of undesirable models of deformation. The paper presents comprehensive modelling of previous experimental work in this field, which leads to a re-examination of the process mechanics. This effort resulted in the development of a combined injection forming/upsetting technique. Numerical simulations performed using this technique indicate that a large extension of the formability limit for tubular components is possible.
Aggregate Production Planning Using Genetic Algorithms
Authors: Stockton D J , Quinn L 
Published: February 2007

An aggregate plan is a statement of future resources and finished goods inventory levels that must be made available to enable a manufacturing organization to meet its forecast sales demand. The aggregate planning process must enable the strategic business objectives of a manufacturing organization to be quickly converted into short-term operational plans that are economical to implement. This link between strategy and the day-to-day activities of an organization is becoming increasingly important in enabling organizations to cope with the faster rate at which business objectives must be changed in order to remain competitive. This paper initially examines the aggregate planning process and describes the basic tasks involved. Current methods of setting aggregate plans are then compared and the main limitations of such techniques highlighted. Using an aggregate planning example, the paper then explains how genetic algorithms can be used to develop such plans and illustrates how this type of algorithm provides the means by which the limitations of existing aggregate planning techniques can be overcome.
Theoretical and Experimental Investigations of Coolant Flow in Inlet Channels of the BTA and Ejector Drills
Authors: Astakhov V P , Subramanya P S , Osman M O M 
Published: February 2007

The coolant flow through inlet annular channels in BTA and ejector drills is investigated. The study was conducted in order to understand the influence of the channel's parameters (the channel's clearance variation along its length and eccentricity) on the coolant pressure distribution and hydraulic resistance. A new design of the ejector drill with the eccentrical location on the inner tube is proposed. A study is made of the stability in the coolant flow in the inlet annular channels. The appearance of instability is explained by the presence of Taylor macrovortices in these channels under certain combinations of boring bar rotating velocity and axial flow velocity. In order to define the unstable regimes (the critical Reynolds numbers), the mathematical model for non-isothermal flow through the annular channel is solved. The heat transfer from the swarf to the incoming coolant is investigated under different flow conditions.
Modelling and Simulation of the Operational and Information Processing Functions of a Computer-Integrated Manufacturing Cell
Authors: Bartlett H , Wong R 
Published: February 2007

This paper investigates the information processing function of a computer-integrated manufacturing (CIM) system, which is usually neglected by engineers when they study the performance of a manufacturing system. The feasibility of developing a complete simulation model which would include both the operational and information processing functions is therefore considered. In order to achieve this, a typical pick-and-place manufacturing cell was considered in which 46 devices were connected to a local area network (LAN). Two independent simulation tools, SIMAN* and L-NET†, were used in order to develop the complete model. The model was evaluated and used to study the performance of the pick-and-place cell using different communication protocols such as the IEEE 802.3 carrier sense multiple access with collision detection (CSMA/CD), IEEE 802.4 token bus and the IEEE 802.5 token ring. Results presented in this paper show that with careful design and simulation it is possible to develop a complete model which includes both operational and informational processing functions. Although the example of the pick-and-place cell is relatively simple the technique adopted could be applied to any CIM system. Results have also shown that for the pick-and-place cell considered in this paper an IEEE 802.3 CSMA/CD protocol operating at 10 Mbps would guarantee access to the network within the shortest station processing time.
Technology Management: A Process Approach
Authors: Gregory M J 
Published: February 2007

This paper proposes a framework for the management of technology based on process thinking. Technology management has traditionally focused on product-oriented research and development (R&D) and assumed a linear model of innovation, starting with science and progressing through technology and design to production. It is now increasingly recognized that this linear approach is only one of many and that production as well as product development can be a powerful and protectable source of competitive advantage. The management of production operations has improved significantly over recent years. Manufacturing companies have begun to replace conventional functional and hierarchical organizations with process approaches to operational activity and management decision making. Such approaches can lend structure and transparency to business operations, link activities more clearly to customer requirements and allow wider involvement of staff and collaborators. It is argued here that the explicit management of product and production technologies, using process thinking, can yield similar benefits. The paper links traditional views of technology management including R&D management, innovation and new product introduction with competence ideas from strategy and a resource perspective from economics. A preliminary ‘process framework’ for technology management is proposed, covering the range of activities from identification to protection. The framework is demonstrated, and its potential benefits explored, in the context of a pilot study of manufacturers in the measuring equipment and domestic appliance industries in Europe, the United States and Japan.
Theoretical Evaluation of the Effects of the Impeller Entrance Geometry and of the Incident Angle on Cavitation Inception in Centrifugal Pumps
Authors: Ardizzon G , Pavesi G 
Published: February 2007

A method, based on quasi three-dimensional analysis, of describing pump cavitation behaviour is proposed. Cavitation performance is related to impeller entrance design and the influence of the angle of attack of the leading edges on the flow is studied. Coefficients are derived from the pressure drop due separately to the vanes and shroud. The influence of incident angle on cavitation is shown as a function of the blade geometry and discussed. By comparison with experimental data on centrifugal pumps, it is shown that the present model can simulate the characteristics of inception cavitation at design and off-design conditions.
An Experimental Investigation into Bearing-Induced Spindle Vibration
Authors: Aini R , Rahnejat H , Gohar R 
Published: February 2007

This paper describes experiments carried out to investigate the frequency response of a grinding machine tool spindle supported by preloaded angular-contact ball bearings. The experimental apparatus includes a loading device to simulate grinding head radial loads. The frequency spectra obtained show bands of frequencies associated with the ball passage frequency. The spectra also include bounce and rocking vibration modes of the assembly, where the supporting bearings act as non-linear springs. Good correlation of the dominant frequencies was obtained with the results of the theoretical models published elsewhere.
Mechanical Hysteresis in Force Transducers Manufactured from Precipitation-Hardened Stainless Steel
Authors: Allgeier T , Evans W T 
Published: February 2007

A non-linear, anelastic stress-strain relationship, hereafter called mechanical hysteresis, which leads to a significant error in the output signal of electrical resistance strain gauge force transducers, has been confirmed to be a general phenomena in precipitation-hardened stainless steels. The mechanism of mechanical hysteresis has been found to be due to the material behaviour; nevertheless, the design of the force transducer and details of the electrical resistance strain gauges could impose further minor effects on the size of the error. Some of the secondary influencing factors (for example loading and mounting details) have been eliminated in the course of the investigation. Using a specially developed heat treatment process, it has been possible to substantially reduce the hysteresis error, which in turn improves the force transducer accuracy.