bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Study of the Braking Performance of Motor-Cyclists With an Integrated Braking System
Authors: Mortimer R G 
Published: February 2007

The purpose of the study was to evaluate the braking performance of motorcyclists using an integrated front and rear brake by comparison with conventional separated front and rear brakes. Stopping distances and the occurrence of wheel locking were measured in braking runs on a straight, flat asphalt surface, in dry and wet conditions, using the front brake only, the rear or integrated brake and both the front and rear or integrated brakes. Speed prior to braking was 40.3 km/h. It was found that mean decelerations using front brakes alone were the same for all motorcycles on the dry and wet surfaces, and significantly greater than rear brakes alone for the dry road. The integrated (foot) brake provided significantly greater mean deceleration performance than rear (foot) brakes on both surfaces. The use of both brakes provided significantly greater mean decelerations than rear brakes alone, on the dry and wet surfaces, but not the integrated brake; and use of both brakes on the motorcycle with integrated brakes produced significantly greater mean decelerations than front brakes alone on all the motorcycles on the wet surface. There were no statistically significant effects of test conditions on the mean frequency of wheel locking, but they were least frequent with the integrated brake. It was concluded that inexperienced and experienced riders could obtain substantial improvements in braking with an integrated braking system which should reduce their involvement in collisions. Further studies should be made on surfaces of lower coefficient of friction, gravel and on curves.
The Development of Advanced High Speed Vehicles in Sweden
Authors: Andersson E , Nilstam N 
Published: February 2007

The rail network of Sweden is characterized by frequent curves, which limit the speed of conventional rolling stock to moderate levels. Speed of travel is, however, probably the most important factor in competition between different modes of transport, both now and in the future. For economic reasons the existing track must be used, with minimum modifications. Effort in Sweden has therefore been concentrated on the development of a new technology, making it possible to run at 35–60 per cent higher speeds on existing track. At these higher speeds comfort levels and track forces must not be worse than for current rolling stock running at present speeds on the Swedish main line track. In order to satisfy these requirements, future vehicles must be equipped with car body tilting, and must also exhibit food dynamic interaction with irregular track. Swedish State Railways (SJ) and ASEA have jointly developed and tested a new concept, including hydraulic or pneumatic car body tilting and radial steering bogies. These bogies allow for high speed through curves without excessive lateral forces and the associated wear on wheels and rails. In this bogie it has been possible to optimize primary suspension and damping parameters so as to maintain stability without hunting at speeds of up to at least 200 km/h. An experimental train set, type X15, was the subject of extensive tests during the period 1975–82. The design of the bogies and car body tilting systems has been supported by computer simulation programs. New methods of analysis have been developed and validated as an integral part of the development project. The simulation technique has proved to be very useful and accurate in the prediction of vehicle dynamic behaviour. Also some tests of passengers' opinions on comfort in tilting trains have been carried out.
An Analytical Approach to the Estimation of the Performance of Steam Turbine Cycles Off-Design
Authors: Weir C D 
Published: February 2007

In estimating the performance of a real steam turbine cycle off-design it is essential to ensure that the flows as determined by heat balance conditions are compatible with the flow-passing capabilities of the stage groups of the machine. Once this condition of compatibility is satisfied the stage group inlet and outlet pressures are uniquely established and these, in conjunction with the (assumed known) locus of the off-design stateline, allow the off-design performance in terms of output and heat rate to be determined. In the case of a condensing-only cycle operating under straightforward part load condition it is a relatively simple matter to arrive at the stage group pressures consistent with both the heat balance and the flow-passing characteristics. Under certain more extreme off-design conditions, and also in the case of passout machines where the work output and the passout quality may vary independently over a rather wide range, the problem of ensuring compatibility is, however, less easily solved. This is an aspect of steam turbine cycle design which does not appear to have been systematically discussed in the open literature. The method presented in this paper is based on an analytical approach which permits solution by a rapidly convergent iterative technique. The stage group pressures arrived at in this fashion, and hence the estimate of thermal performance based upon them, correspond to a degree of accuracy quite sufficient for all purposes to those of the equivalent real cycles.
Marine Technology—Present and Future
Authors: Thompson R V 
Published: February 2007

The paper attempts to present a scenario of the change in energy sources and availability occurring in the world today and its effect on trading patterns. As a result of this analysis, an impression of shipping reguirements and hence potential demand is developed. Associated required engineering developments are postulated both in the area of traditional sea-going trade and also offshore and subsea systems. The progress of specific related research projects and their expected contributions to technological expertise and operational availability is presented. The precarious position of the UK industry versus the rest of the world is highlighted, and a plea made for a technological lead recovery.
Diesel Engine Research at High B.M.E.P.
Authors: Osborne A G 
Published: February 2007

Demands for more power from the turbocharged diesel, without increase in bulk or weight, has led to an increase in levels of mean effective pressure by the application of high-pressure turbocharging. An investigation was conducted to determine engine performance under high b.m.e.p. conditions and this paper presents results of the experimental part of the research programme. Test work was carried out on a single-cylinder research engine equipped with an independent pressure-charging facility. Boost pressure ratios up to 6.2:1 were used with the geometric compression ratio reduced, in stages, to 8:1, to limit peak cylinder pressure. Power levels up to 35.4 bar b.m.e.p. were produced.
Applications of Linear Programming to Engineering Metrology
Authors: Chetwynd D G 
Published: February 2007

Computer-based metrology now makes use of exchange algorithms for computing best-fit geometries in which the solution is obtained by a series of iterations each involving the exchange of one previously unused data point for one of the dominant points of the previous iteration according to formal rules. While conferring large advantages in specific circumstances, their major significance is that of being examples of a class of optimization of much wider applicability. This paper examines the theoretical basis of these algorithms in linear programming and develops a general approach to the solution of this class from which new applications can be derived. To maintain an engineering context in the analysis, practical examples are used, mainly from the field of roundness measurement.
Quality Management
Authors: Morrison S J 
Published: February 2007

The importance of quality and reliability as key determinants of competitiveness is emphasized and comparisons are made with the Japanese as competitors in international trade. The interdisciplinary nature of quality assurance is discussed and the need for bridges to be built between science, engineering, and management is identified. A quality management model is presented in the conventional planning/organizing/directing/controlling framework of the management discipline. The paper is written by an engineer for an engineering readership, but it is hoped that it will find wider acceptance among chief executives and managers in industry generally.
Computer Prediction of Cyclic Excitation Sources for an External Gear Pump
Authors: Foster K , Taylor R , Bidhendi I M 
Published: February 2007

A description is given of a computer program for investigating the performance of the external gear pumps under varying conditions with the special emphasis on the examination of pressure distributions within the pump, i.e. excitation forces for the vibration of the pump case and the variation in flow generated by the pump. Measurements are presented for the variation with time of tooth space pressure and the results are compared with the theoretical predictions from the computer program.
The Manufacture of a New Generation of Headlamp Reflectors
Authors: Monk J F , Morgan L S 
Published: February 2007

This paper reviews the development and implementation of a radically new manufacturing system for the production of advanced automobile headlamp reflectors using a thermosetting plastics material. The new system has replaced the traditional method which involved pressed and fabricated steel reflectors. This project has required wide ranging interaction of many business functions. They include sales and marketing, material process and production research and development, product design and development, and factory production engineering. Product design in particular has benefited from the improved optical performance of the new reflectors, providing beams of a higher photometric output and having a more closely defined pattern. This has been achieved whilst product quality, durability and competitiveness have been improved. In addition, the high aspect ratio headlamps made possible by the plastics reflectors have allowed lower vehicle bonnet designs, resulting in lower coefficients of drag and thus improved fuel economy.
Front End Control Schemes for Pneumatic Servo-Driven Modules
Authors: Nagarajan R , Weston R H 
Published: February 2007

This paper describes an approach which can be used to improve the dynamic characteristics of pneumatic servo drives. The approach is based on an outer decision loop which modifies the command issued to an existing closed loop drive. This outer loop is designed to generate a set of initial (front end) control sequences at the start of any ‘point-to-point’ move. A learning procedure is also incorporated in the scheme to obtain an optimized set of control parameters which can produce a specified quality of response. The paper describes how the front end control scheme can be implemented in software, to improve the dynamic performance of microprocessor controlled pneumatically actuated robot modules which have been designed at Loughborough University and recently released in the UK market by Martonair Limited. Experimental results are presented which show that the scheme can improve the quality of response in terms of overshoot and positioning time.
On the Self Diffusion of Water Vapour
Authors: Bakhtar F , Zidi K 
Published: February 2007

Calculated values of the coefficient of self diffusion of steam, based on a theoretical model and covering the pressure range 0.07–27 bar, are presented. By considering the equilibrium vapour pressure surrounding a large droplet placed in its own vapour, its temperature, and hence the temperature field, have been estimated. From the heat transfer rate, the rate of mass transfer and consequently the coefficient of self diffusion have been deduced. The calculations are repeated over a large range of conditions and the results correlated. Application to the nett mass transfer rate is next considered. By drawing comparisons with the case of a droplet in the free molecule regime and other transport processes, an expression covering the whole Knudsen number range is developed.
Torispherical Shells under Internal Pressure—Failure due to Asymmetric Plastic Buckling or Axisymmetric Yielding
Authors: Galletly G D , Błachut J 
Published: February 2007

In the diameter-to-thickness range 250 < D/t < 1000, internally pressurized torispherical shells can fail either by plastic buckling or by axisymmetric yielding. However, the present Code rules cater only for the axisymmetric yielding mode and they also restrict the D/t ratios to being less than 500. The rules are based on limit analysis results and these can be conservative for this problem. With regard to internal pressure buckling, there are as yet no design rules in either the American or the British pressure vessel Codes to prevent its occurrence. To provide guidance for a more accurate formulation of design rules for both of these failure modes over the range 300 < D/t < 1500, the authors have made a series of calculations to determine the values of Pcr (the internal buckling pressure) and pc (the axisymmetric yielding pressure) for perfect torispherical shells. The availability of these results, obtained with a finite-deflection shell theory, enables curves to be drawn showing when buckling is the controlling failure mode and when axisymmetric yield controls. A comparison is also made, for D/t < 600, between the controlling failure pressures mentioned above and the Drucker-Shield limit pressures. The ratio between the former and the latter varied between 1.2 and 1.8, depending on the geometry of the shell and the magnitude of the yield point, σyp. Considerable economies in the designs of many torispherical shells could, therefore, be achieved if the relevant sections of the Codes were to be modified to take advantage of the foregoing results. The controlling failure pressure curves also indicate how Code rules to prevent plastic buckling for D/t > 500 might be formulated. For the benefit of designers, the numerical values of pcr and pc were transformed, using curve-fitting techniques, into simple approximate equations. Although these equations are for perfect torispherical shells, they should be very beneficial when analysing the related problems of fabricated torispheres in practice.
An Experimental Investigation of the Performance of Equiangular Annular Diffusers with Swirled Flow
Authors: Elkersh A M , Elgammal A H , Maccallum N R L 
Published: February 2007

An experimental study of the influence of geometrical parameters and swirl on the performance of equiangular diffusers is presented. Three diffusers were tested over a range of inlet swirls up to 45°, the swirls being of free vortex distribution. The data presented indicate similar flow patterns for different cant angles, and show that the centrifugal forces due to swirl stabilize the flow on the outer wall, while increasing the tendency towards separation at the inner wall. Diffuser performance improves as the inlet swirl increases up to 30°, the improvement being influenced by area ratio and cant angle. A further increase of swirl causes a deterioration of performance.
The Effect of Manufacturing Variations on the Performance of Externally Pressurized Gas-Lubricated Journal Bearings
Authors: Stout K J 
Published: February 2007

This paper extends the previous work on the hybrid operation of externally pressurized gas bearings to include the effects of manufacturing variations on design performance of the slot entry configuration. Six aspects of manufacture are considered, and include the departure from the design conditions of (a) bearing clearance, (b) feed slot thickness, (c) bearing form, (d) bearing roundness, (e) bearing member alignment, (f) feed slot geometry. Computer predictions of the above effects have been made by introducing modifications to the programs developed to model gas bearing performance developed for solution using a finite difference technique. The results show how the load capacity of the bearings is affected by the departure of dimensions from their design conditions. The magnitude of the departure from the design performance is demonstrated in the figures presented. The performance predictions for the slot entry bearing are compared with results obtained from the orifice compensated journal bearing previously reported. Guidance is given on the limits of departure from initial design conditions which should be allowed for both types of bearing. Confirmation of the accuracy of design predictions has been achieved in this investigation by conducting experiments using test bearings which were very carefully measured to establish the real tolerance on manufacture. These bearings were tested on a specially designed experimental rig.
The Design of Mitred Bends—A Background to BS 806 : 1975 Amendment No 3
Authors: Battle K , Carmichael G D T , Cresswell E , Morse D , Porter H , Popplewell P L , Riley K 
Published: February 2007

To satisfy a requirement within the high pressure pipework industry in the UK, PVE/10 of the British Standards Institution established a Working Party to produce recommendations on the design and application of gusseted or mitred bends. The ultimate conclusions of the Working Party were eventually published within Amendment AMD 3545 to BS 806 ‘Ferrous pipes and piping installations for and in connection with land boilers’. Prior to this amendment BS 806 provided only limited guidance on the design of such bends, based on rules derived from custom and practice. AMD 3545 provides more extensive guidance than previously, based on experimental data and analysis and provides guidance on pipework design. This paper describes the background to the amendment and provides most of the reasoning behind the conclusions drawn by the Working Party.
Simulating for ‘Resource Optimization’ in Robot-Assisted Automatic Assembly
Authors: Rahnejat H 
Published: February 2007

In most manufacturing systems emphasis is now given to resource flexibility in operation. The aim is to respond swiftly to changes in product mix and/or market demands. Discrete event computer simulation is seen as a tool in defining a suitable system configuration at the preliminary design stage. Furthermore, simulation in dynamic form can represent the interactions between the system components and provide a detailed prediction of its performance. Although many existing computer simulation packages have reached a good level of general purpose modelling, by and large they lack the required versatility to deal with some specific features of manufacturing systems. One such important area is the robot-assisted automatic assembly where minimization of non-productive activities in the product assembly cycle is of vital interest. This paper introduces a flexible modelling technique which identifies the resource utilization and optimization levels during the individual processes of a product assembly cycle. Within the working constraints of an assembly system, an ‘optimal’ robot sequential cycle is obtained by implementing this modelling technique in GPSL (general purpose simulation language).
The Impact of Advanced Manufacturing Technology on a Mature Industry
Authors: Mackenzie G R 
Published: February 2007

TI Group plc is the largest private sector tube-maker in the UK. Group companies manufacture specialist and bearing tube as well as commodity welded and cold-drawn carbon seamless tube. A substantial proportion of tube output is exported from the UK. Continuing competitive pressures and the changing nature of demand from both home and export markets are forcing reappraisal of TI Group's approach to tube manufacture. TI Group sees the maintenance of manufacturing competitiveness as a key element of securing a profitable future, and policy now requires operating subsidiaries to give full weight to manufacturing considerations when formulating their business strategies. Against this background, TI Group tube manufacturing companies are devising plans and making fundamental changes to apply advanced manufacturing technology to their processes and manufacturing control systems so as to give a more flexible response to market demand whilst achieving further cost reductions.
Computer Integration of Advanced Manufacture
Authors: Crookall J R 
Published: February 2007

An inhibiting misconception in the advancement of manufacturing is the widely assumed inevitability of de-humanization of the workplace, and adverse effects of machines taking over. Manufacturing of the future must be: business-led, and targeted to optimize corporate opportunities; planned, equipped and operated accurately to quantifiable, comprehensible criteria; interfaced with and supportive of the the people who run the system. Therefore analysis and rationalization of the total manufacturing system and strategy should precede computer integration. Techniques such as production flow analysis and computer simulation are important ways of achieving this, but there are others also; these will be considered in the paper. This results in more logical and efficient processing, materials handling and therefore manufacturing flow and orderliness, promoting an effective basis of visibility, information and control, and maximum benefits from computer integration. The growing science of artificial intelligence will complement conventional software engineering skills. A key issue is the technical skills and training of literate manufacturing systems engineers and managers. In optimized manufacture human judgement increasingly needs the control and information systems back-up that computer integration is capable of providing, particularly against the background of increasing rate of technological change, greater complexity of tasks and interactions with which companies' corporate manufacturing and marketing strategies will have to deal in the future.
Modelling the Ends of Compression Helical Springs for Vibration Calculations
Authors: Pearson D 
Published: February 2007

The squared ends of compression helical springs are modelled as fixed ends with adjacent pinned supports. A theory is developed for the calculation of the natural frequencies, its predictions being compared with experiments on springs with about 2 1/2, 4 and 8 1/2 active turns, using two new designs of test rig. The discrepancy between theory and experiment is typically 1 per cent. The paper contains discussions of the application of the theory to forced vibration calculations, and the modelling of other types of end. Two methods are reviewed for the design of helical springs with the object of avoiding vibration problems.
Dynamic Analysis of an Axial Piston Pump Swashplate Control
Authors: Zeiger G , Akers A 
Published: February 2007

A mathematical model of an axial piston pump is described which consists of a second-order differential equation of the swashplate motion and two first-order equations describing the flow continuity into the pump discharge chamber and into the swashplate control actuator. The equation of the swashplate angle contains torque components due to operating states. A method is presented by which the average torque can be computed for a pump of given geometry and at any given set of operating conditions. From the calculated average torque, the coefficients of the basic equation can be evaluated; agreement to within 10 per cent of experimental values for torque has been achieved. A state variables analysis of the dynamic behaviour has shown that there are two dominant poles at low frequency and that the damping ratio associated with these poles reduces by approximately one half when the downstream control volume increases by a factor of three, and varies from 0.84 to 0.48 as the pump rotational speed increases from 126 to 209 rad/s. It has been concluded that the assumption of linear variation with the basic parameters, which is a necessary prerequisite for the use of states variables analysis, is justified. The work outlined in this paper represents a step in the design process associated with the optimal control of an axial piston pump.