bluuebunny/crossref_metadata_2025 huggingface dataset:
A Phenomenological Model for ‘Barrel’ Swirl in Reciprocating Engines
Authors: Benjamin S F
Published: February 2007

Recent studies have shown that a ‘barrel’ swirl type of flow in spark ignition engines may be exploited to provide improved fuel economy and reduced emissions. A simple analytical phenomenological model of ‘barrel’ swirl has been developed for a disc-type combustion chamber that describes the vortex behaviour during compression. The model shows that the vortex can spin up during early compression but then rapidly decays as top dead centre is approached due to the high fluid shear stresses that develop. This mechanism of swirl arrestment is shown to dominate that due to wall friction. The model confirms experimental findings that show rapid swirl decay in certain four-valve engines.
An Experience in Product Development
Authors: McKnight J
Published: February 2007

This Address traces the 1992–93 Chairman's career, which has mainly been centred in the automotive industry. The Address draws on some examples from experiences in the design and introduction of commercial vehicle and rail products, suggesting some working practices to be considered in the achievement of sound product development. The Address also recommends that members of the Institution continue their promotional efforts of professional engineering and urges them to become more active in this respect, especially in the workplace and with their contacts in secondary schools.
Developments in Two-Stroke Cycle Engine Exhaust Emissions
Authors: Kenny R G
Published: February 2007

This paper is concerned with the exhaust emissions from two-stroke cycle spark ignition engines and the means being investigated to reduce them. The simple two-stroke engine has inherently low levels of NOx emissions and high levels of hydrocarbon emissions. The reasons for these emissions characteristics are explained by reference to the open literature.

The two-stroke engine is used in a wide range of applications including low-cost, low-output mopeds and high-performance motorcycles. More recently there has been a resurgence of interest in the two-stroke as an alternative to the four-stroke engine for automotive use. A number of the recently reported approaches to emissions control are reviewed, including the use of exhaust oxidation catalysts in simple low-cost engines and direct fuel injection on more costly, multi-cylinder engines.
Monitoring of Gasoline Fuel Distribution in a Research Engine
Authors: Winklhofer E , Fraidl G K , Plimon A
Published: February 2007

Fuel distribution in gasoline engines has significant influence on the cyclic stability of charge ignition and combustion, and hence on engine performance parameters related to the variation of combustion and heat release. There are numerous ways to influence in-cylinder fuel distribution by means of mixture preparation systems, engine aspiration or by combustion chamber geometry itself. However, methods to observe in-cylinder fuel distribution are scarce, and very often charge distribution—homogeneous or highly stratified—is just heuristically assessed, based on engine performance data. Therefore, a method has been devised which allows observation of vaporized fuel in the cylinders of optically accessed engines. The method, based on the absorption of infra-red laser light radiation by hydrocarbon molecules, needs optical access to the combustion chamber to transmit a laser beam of appropriate wavelength and to monitor the attenuation caused by absorption and scattering.

The paper describes the concept of the measurement technique and its application to an optically accessed single-cylinder research engine. The engine is equipped with a transparent cylinder liner to allow investigation of the entire cylinder volume. In order to evaluate the feasibility of the method, the response of the line-of-sight absorption measurements to various engine operating modes was investigated. A comparison with actual engine data showed that fuel distribution, as governed by the injector operating mode, can have significant influence on combustion and cycle-to-cycle stability.
Strategies to Meet Worldwide Heavy-Duty Diesel Emission Standards
Authors: Cartellieri W , Kriegler W , Schweinzer F
Published: February 2007

The most severe exhaust emission standards for heavy-duty diesel engines will be introduced in the United States in 1994 and 1998 and standards of similar severence have been announced in Japan and in Europe. While in the United States emissions have to be measured in a transient cycle, in both of the other two geographical areas, Europe and Japan, special steady state cycles have been adopted for certifying heavy-duty diesel engines. In the first part of the paper the main characteristics of the three test procedures are compared and those load-speed operating areas identified which most significantly contribute to cycle emissions. Of these, NOx and particulates are the most challenging components. Strategies to reduce them are outlined in later parts of the paper. Emphasis is placed primarily on technologies for in-cylinder emissions reduction, but exhaust gas aftertreatment by diesel oxidation catalysts is also addressed. The achievements of these technologies will be demonstrated by test results from heavy-duty diesel engines of the 1 to 2 litre/cylinder categories.
The Use of Tangential Offtakes for Energy Savings in Process Industries
Authors: O'Doherty T , Biffin M , Syred N
Published: February 2007

Swirling flows occur in many processes within industry with little consideration given to pressure recovery. High tangential velocities occur in the exhaust nozzle which have been shown to persist for up to 20 pipe diameters downstream. This kinetic energy is dissipated by turbulence and friction and is unnecessarily lost. There is potential to recover this energy and reduce operating costs.

This paper shows that a tangential offtake with associated diffuser can be used to recover up to 45 per cent of the pressure loss, with an accompanying reduction in energy consumption. It has particular application in the cement and process industries, and has been tested on a novel prototype cement raw meal preheater tower.
An Experimental Study on the Lateral Impact of Fully Clamped Mild Steel Pipes
Authors: Jones N , Birch S E , Birch R S , Zhu L , Brown M
Published: February 2007

This report presents some experimental data that were recorded from 130 impact tests on mild steel pipes in two drop hammer rigs. The pipes were fully clamped across a span which was ten times the corresponding outside pipe diameters which lie between 22 and 324 mm. All of the pipes except five had wall thicknesses of 2 mm approximately and were impacted laterally by a rigid wedge indenter at the mid span, one-quarter span or near to a support. The impact velocities ranged up to 14 m/s and caused various failure modes.

Some comparisons between two sets of experimental results indicate that the laws of geometrically similar scaling are almost satisfied over a scale range of approximately five.
Dutch Environmental Policy and Netherlands Railways
Authors: Kaper H
Published: February 2007

This paper considers various factors that influence Dutch environmental policy as regards the Netherlands Railways and discusses environmental balance considerations. Problems with implementing regulations are discussed.
A Method for Measuring the Dynamic Behaviour of the Rome-Florence High-Speed Track Switch Manoeuvring System
Authors: Bracciali A , Biagiotti M
Published: February 2007

A mathematical model of the dynamic loads induced at a switch machine and at the rails by the passing of a train was formulated and validated by physical tests. Attention was focused specifically on the switch machine itself and therefore the data gathered refers strictly to the attachment elements of the switch machine to the track and locally the track in the area of attachment.

The research is part of a series of projects that aim to establish the factors that must be considered during the design of a switch machine. An accurate mathematical model of the connection elements between the track and the switch machine is helpful, especially in this period of widespread adoption of high-speed trains and the new working conditions that this imposes, in order to ascertain the characteristics of the accelerations transmitted to the switch machine and, as a consequence, to design the connection system of the machine to the track, based on these criteria. The data acquired can also be used for the construction of a realistic test bench to further improve test procedures. The pursuit of this project is a fundamental step in understanding the factors involved in the design of a switch machine.
Design of High-Tech Metre Gauge Coaches on Indian Railways
Authors: Wadhwa K B L
Published: February 2007

This paper traces the steps taken by the Research Designs and Standards Organisation (RDSO) of Indian Railways in the past to improve the metre gauge bogie design, which resulted in crossing the age-old speed barrier of 75 km/h, initially in 1977, when the Pink City Express was introduced at a maximum permissible speed of 100 km/h. The ‘Sperling ride index’ achieved at that time at the 110 km/h test speed was nearing 3.2 in the lateral mode and 3.33 in the vertical mode.

Major design modifications are described that were carried out in the conventional metre gauge bogie/body, using indigenous technology, while designing high-tech metre gauge (MG) coaches. These are suitable for running on Indian Railways' track at a maximum permissible speed of 120 km/h and at the same time provide superior riding characteristics (with sperling ride index restricted to 2.75) comparable to those available on the main line coaches of 1000 mm gauge in the developed countries of the world.
British Aerospace Hawk into the 1990s
Authors: Chisnall G
Published: February 2007

The paper covers a review of the British Aerospace Hawk aircraft programme. An overview of the main development events and entry into RAF service is included, which emphasizes the versatility of the basic concept. This was deliberately designed in by the original team in order to maximize the subsequent export potential of the aircraft. That this was an outstanding success is shown in the outline of the main export variants to date.

This background gives context to the main body of the paper, in which the new Hawk aircraft developments, the 100 and 200 series respectively, are described. These advanced versions are intended to maintain the market dominance of Hawk throughout the 1990s and beyond.

A final, brief review of the broader environment within which BAe is carrying out its private venture development of Hawk is included as a conclusion to the paper.
Working Top-Down: Cost Estimating before Development Begins
Authors: Pugh P G
Published: February 2007

The present state of the art of cost estimating is reviewed with particular reference to its employment in connection with strategic decisions such as whether to launch a major project or not and, hence, when information concerning the project is limited and/or incomplete.

The processes of ‘top-down’ cost estimating are described in sequence, starting with the gathering of data and its analysis followed by the formulation of costing assumptions and the derivation of cost-estimating relationships and ending in the application of those to yield cost estimates for the project in question. At each stage, the description is accompanied by practical advice and warnings of some common pitfalls.
Bioengineering Activities in the Department of Mechanical and Production Engineering at the University of Limerick
Authors: Little E G
Published: February 2007

This paper outlines the main areas of bioengineering research in the Department of Mechanical and Production Engineering at the University of Limerick.
Acute Vibration—Its Effect on Digital Blood Flow by Central and Local Mechanisms
Authors: Greenstein D , Kester R C
Published: February 2007

In order to establish underlying mechanisms responsible for the vasospastic disorder vibration white finger (VWF), the acute effect of vibration on digital blood flow was assessed. Thirteen patients with primary Raynaud's phenomenon (RP), 15 patients with VWF and 13 controls were exposed to acute vibration in the middle digit of one hand for 1 and 3 minutes. Blood flow was measured in that digit and in the middle finger of the contralateral hand using strain gauge plethysmography before and after vibration. The measurements were then repeated following digital nerve blockade using 2% Lignocaine in the vibrated digit. The results demonstrate that vibration affects digital blood flow through two independent mechanisms. Vibration appears to cause both an axonal vasoconstrictor reflex and an active local vasodilation phenomenon. In patients with established vasospastic disorders this vasoconstrictor reflex is exaggerated.
A Model of Human Knee Ligaments in the Sagittal Plane: Part 1: Response to Passive Flexion
Authors: Zavatsky A B , O'Connor J J
Published: February 2007

The development of a mathematical model of the knee ligaments in the sagittal plane is presented. Essential features of the model are (a) the representation of selected cruciate ligament fibres as isometric links in a kinematic mechanism that controls passive knee flexion and (b) the mapping of all other ligament fibres between attachments on the tibia and femur. Fibres slacken and tighten as the ligament attachment areas on the bones move relative to each other. The model is used to study the shape and fibre length changes of the cruciate and collateral ligaments in response to passive flexion/extension of the knee. The model ligament shape and fibre length changes compare well qualitatively with experimental results reported in the literature. The results suggest that when designing and implanting a ligament replacement with the aim of reproducing the natural fibre strain patterns, the surgeon must not only implant through the natural attachment areas but must also maintain the natural fibre mapping and render all fibres just tight at the appropriate flexion angle.
A Three-Dimensional Morphometrical Study of the Distal Human Femur
Authors: Zoghi M , Hefzy M S , Fu K C , Jackson W T
Published: February 2007

The objective of this paper is to present a method to describe the three-dimensional variations of the geometry of the three portions forming the distal part of the human femur: the medial and lateral femoral condyles and the intercondylar fossa. The contours of equally spaced sagittal slices were digitized on the distal femur to determine its surface topography. Data collection was performed using a digitizer system which utilizes low-frequency, magnetic field technology to determine the position and orientation of a magnetic field sensor in relation to a specified reference frame. The generalized reduced gradient optimization method was used to reconstruct the profile of each slice utilizing two primitives: straight-line segments and circular arcs.

The profile of each slice within the medial femoral condyle was reconstructed using two circular arcs: posterior and distal. The profile of each slice within the lateral femoral condyle was reconstructed using three circular arcs: posterior, distal and anterior. Finally, the profile of each slice within the intercondylar fossa was reconstructed using two circular arcs: proximal-posterior and anterior, and a distal-posterior straight-line segment tangent to the proximal-posterior circular arc. Combining the data describing the profiles of the different slices forming the distal femur, the posterior portions of each of the medial and lateral femoral condyles were modelled using parts of spheres having an average radius of 20 mm. The anterior portion of the lateral condyle was approximated to a right cylinder having its circular base parallel to the sagittal plane with an average radius of 26 mm. The anterior portion of the intercondylar fossa was modelled using an oblique cylinder having its circular base parallel to the sagittal plane with an average radius of 22 mm. Furthermore, it is suggested that the distal portion of the lateral femoral condyle could be modelled using parts of two oblique cones while the distal portion of the medial femoral condyle could be modelled using a part of a single oblique cone, all cones having their circular bases parallel to the sagittal plane. It is also suggested that the posterior portion of the intercondylar fossa could be modelled using two oblique cones: a proximal cone having its base parallel to the sagittal plane and a distal cone having its base parallel to the frontal plane.
Computation of Wear in Artificial Heart Valves
Authors: Kombalov V S , Tatarinov V F
Published: February 2007

In order to assist with the prognosis of wear processes in low profile disc heart values, an approximate haemodynamic theory has been used for the determination of opening and closing dynamics of these valves, together with the most developed theory to date of frictional fatigue. The heart valve element wear was defined by solving the contact problem, which takes account of changes to the contact surface form as a consequence of wear. Calculated values are compared with in vivo wear data for artificial heart valves. The proposed model for estimating wear in artificial heart valves allows an optimization to be made of the wear resistance in available designs and to predict the wear resistance of artificial heart valves at the design stage.
Two-Dimensional Computer Control System Analysis
Authors: Whalley R , Zeng Z
Published: February 2007

Digital control system models in two dimensions are considered. A stability algorithm for realizations of arbitrary order is derived. Typical results illustrating the assessment of absolute and relative stability for two-dimensional transfer function models are presented.
A Second-Law Analysis of Air-Standard Diesel—Turbocharger–Bottoming Cycles
Authors: Woodward J B
Published: February 2007

It is asserted that some of the mechanical engineering literature on power cycle analysis does not make sufficient use of the second law of thermodynamics. Advantages of second-law use are listed and then demonstrated through development by equations by which analysis of an air-standard diesel cycle can incorporate constant-pressure turbocharging and a Rankine bottoming cycle. Steps towards application to real machinery are also demonstrated. Four numerical examples are included.
Design and Performance of a High-Pressure Ratio Turbocharger Compressor Part 2: Experimental Performance
Authors: Whitfield A , Doyle M D C , Firth M R
Published: February 2007

The performance of two turbocharger impeller designs was evaluated experimentally. The compressor design requirement was for a pressure ratio of 3.6, with a peak pressure ratio of 4.3 at a maximum non-dimensional impeller speed of 1.66. Due to the stress-limited speed the impeller discharge blade backsweep had to be restricted and the application of prewhirl was considered from the outset as a means of extending the operating range. An impeller, designated A, was designed with 25° of prewhirl applied. A second impeller, designated B, was designed with zero prewhirl for comparison purposes, but was not manufactured. A third impeller, C, was manufactured, in place of impleller B, through the modification of an existing design. This experimental study includes the assessment of this third impeller together with impeller A.
Steam Explosions in Boiler Ash Hoppers
Authors: Stanmore B R , Desai M
Published: February 2007

Steam explosions are experienced in the ash hoppers of coal-fired boilers when hot ash falling from heat-transfer surfaces enters the water pool. Pellets of ash from three Australian power stations were formed in the laboratory and sintered under different conditions to simulate boiler ash deposits. When these were reheated and dropped into water, explosions were generated in isolated cases. The offending pellets were all lightly sintered and disintegrated into individual ash grains. The occurrence of explosions is unpredictable because of the extremely limited range of ash lump conditions under which they appear.
Scottish Nuclear Limited: The AGR—Past, Present and Future
Authors: Anderson D , Barnes G G
Published: February 2007

This article reviews the historical development of the AGR (advanced gas-cooled reactor) in Scotland from its inception to its current successfully established position. It examines where the AGRs will go in the future and concludes with the strategic role of the existing and new plant in the market-led electricity supply industry.
Model of a Slip Sensor
Authors: Eghtedari F , Hopkins S H , Pham D T
Published: February 2007

This paper describes the mathematical and computer modelling of a photoelastic sensor for slip detection. The main components of the sensor are a photoelastic transducer and a solid state camera. When under stress, the photoelastic transducer generates optical fringe patterns which are captured digitally by the camera. The model developed encompasses the mechanical and optical behaviours of the photoelastic transducer and the switching characteristics of the camera pixels. The model has been employed to study the effects of different design parameters on the sensor's slip resolution.
Intelligent Inspection Planning and Computer Aided Inspection
Authors: Tannock J D T , Lee H , Cox D R , Williams J H Sims
Published: February 2007

Quality inspection is the source of vital information for business control and improvement in manufacturing. This paper describes research at the University of Bristol, in collaboration with Rolls-Royce plc, to develop automated inspection planning and computer aided inspection applications. The inspection planning system involves the representation of inspection features and the manufacturing process model, together with an automated planning mechanism driven by rule-based plan reasoning. The shop-floor computer aided inspection workstation uses hand-held instruments interfaced to a computer, and provides flexible, interactive assistance for the dimensional inspection task. Batch and component traceability and control, together with a range of quality information storage and reporting functions, are provided.
Intelligent Control of the Gear-Shaving Process
Authors: Zhong J S , Qu L S
Published: February 2007

The objective of this paper is to describe how AI (artificial intelligence) and fuzzy logic techniques can be combined to implement an on-line computer control of an axial gear-shaving process in order to improve the quality of workpiece gears. The basic principle of correcting the geometric errors of workpiece gears is introduced. The final knowledge base is obtained by the iterative procedure of trying the expert controller, observing the results and then modifying the control rules accordingly. Inference is provided by a fuzzy logic engine. Experimental results showed that accuracy of the shaved gears was greatly enhanced. The total cumulative pitch error arid the individual pitch error were reduced by approximately two times. In particular, the flank grooves, which commonly occur in the middle of tooth profiles, were removed.
Manufacturing Innovation in the 1990S—Winning Hearts and Minds
Authors: Summerfield P H
Published: February 2007

This paper shows that the United Kingdom has the capability to halt the erosion of its manufacturing base if industrialists, academics, financiers and politicians are able to win the hearts and minds of people at all levels and in all walks of life and convince them that an innovative, long-term strategic plan for manufacturing growth will work. The paper highlights what some British companies have already achieved and suggests ways of bringing manufacturing back to the position it should occupy.
Effect of Vapour Drag on Laminar Film Condensation on a Vertical Rectangular Fin
Authors: Kazeminejad H
Published: February 2007

A simple theory is presented for laminar film condensation of a pure vapour on a vertical rectangular fin which takes account of drag induced on the liquid film by the flow of the condensing vapour. Under these conditions, the governing conjugate differential equations for the fin and condensate flow are solved numerically to determine the fin temperature and condensate film thickness distributions. For the range of parameters investigated, it was found that the reduction in condensate thermal resistance due to vapour shear significantly enhances the heat-transfer rate to the fin and decreases the fin efficiency. The model also provides a clear picture of the relative effect of the gravity force, friction drag and momentum drag on the performance of the fin.
Multiple Contact and Axisymmetric Inflation of Hyperelastic Cylindrical Membranes
Authors: Khayat R E , Derdouri A , Garcia-Rejon A
Published: February 2007

The confined axisymmetric inflation of a hyperelastic isotropic and homogeneous cylindrical membrane, with ends fixed, is examined in this study. The material is assumed to obey the Mooney-Rivlin constitutive model. The radius and thickness distributions of the undeformed cylinder are non-uniform. The problem is formulated to account for single- and multiple contact. At a point of contact, in contrast to most existing formulations on contact problems, the tangency condition between elastic membrane and solid boundary is respected. This translates into compatibility relations which are derived in the form of boundary conditions. Contact is also assumed to be slipless. There are three dimensionless parameters in the problem: (a) the initial cylinder length-radius ratio S, (b) the ratio m = C2 C1 of the Mooney constants and (c) an inflation parameter Rp. The influence of S and m is closely examined in the context of free inflation. Numerical illustrations are given for single- and double-contact problems.
Improved κ-ɛ Modelling of Impeller Flow Performance of a Mixed-Flow Pump under off-Design Operating States
Authors: Fraser S M , Zhang Y
Published: February 2007

Three-dimensional turbulent flow through the impeller passage of a model mixed-flow pump has been simulated by solving the Navier-Stokes equations with an improved κ-ɛ model. The standard κ-ɛ model was found to be unsatisfactory for solving the off-design impeller flow and a converged solution could not be obtained at 49 per cent design flowrate. After careful analysis, it was decided to modify the standard κ-ɛ model by including the extra rates of strain due to the acceleration of impeller rotation and geometrical curvature and removing the mathematical ill-posedness between the mean flow turbulence modelling and the logarithmic wall function.
Shear Flow in Multi-Cell Sections
Authors: Grant C
Published: February 2007

Traditional shear flow calculations for thin-walled multi-cell sections subjected to bending have ignored developments in topological algebra that exploit the independence of a network topology from its physical characteristics. By treating the section as a set of thin limbs connected at end nodes, network theory originally developed for electrical circuits can be applied to the problem. Flow rules similar to those formulated by Kirchhoff almost a century and a half ago are derived from conditions of equilibrium and compatibility.

Each limb of the section behaves as a flow generator which drives the flow around the network. A complete solution can be derived for shear flow and for warping displacement in every limb by solving a relatively small number of fundamental circuit equations, equal to the number of independent circuits in the network. Matrices employed in the solution can be formed directly from the section's topological description.
The dynamics and design of a non-linear vibration absorber
Authors: Gonsalves D H , Neilson R D , Barr A D S
Published: February 2007

This paper presents the design of an efficient non-linear vibration absorber. The system comprises a linear absorber with the addition of a spring between the two masses, which contacts the absorber mass when its displacement exceeds a certain value. The addition of this snubber stiffness facilitates a reduction in the amplitude of the second resonance peak of the linear absorber, which therefore enables the system to be operated over a wider frequency range without reaching larger amplitudes. The modification also has the effect of attenuating the response of the auxiliary mass. The equations of motion for the system are presented and optimization is carried out. A description of an experimental rig that was built follows. The results from the rig are compared with those from numerical simulation and show good correlation.
Resistance of Two Inclined Parallel Flat Plates Placed in Tandem on a Stream-Wise Flat Plate in Two-Dimensional Flow
Authors: Mehta R C , Rao C R , Dubey Y N
Published: February 2007

The paper presents the results of an experimental study on the drag coefficient of two inclined parallel flat plates, placed on a stream-wise flat plate, in tandem, in two-dimensional flow. The effects on the drag coefficient of Reynolds number, the inclination of the plates to the flow direction and the relative spacing between plates were studied. It is observed that, while the Reynolds number has no appreciable effect, the other parameters influence the drag coefficient to a considerable extent. The results are corrected for blockage effect and comparisons are made with the data collected by other investigators.
NOx Emission Control in Oxygen-Rich Exhaust Through Selective Catalytic Reduction by Hydrocarbon
Authors: Iwamoto M , Mizuno N
Published: February 2007

Selective catalytic reduction of nitrogen monoxide by hydrocarbon in the presence of oxygen and sulphur dioxide has very recently been found on copper ion-exchanged ZSM-5 zeolite (Cu-ZSM-5). The reaction proceeds even in the oxidizing atmosphere at temperatures as low as 573 K. Addition of oxygen to the reactant stream is necessary to achieve the selective reduction of nitrogen monoxide. The increment of concentration of hydrocarbon increased the conversion into nitrogen and expanded the active temperature region. After summarizing the new findings on Cu-ZSM-5, the present review introduces catalytic activities of various metal-ion exchanged zeolites and metal-loaded aluminas. Based on the temperature dependence of each catalyst and the change of conversion of nitrogen monoxide into nitrogen with space velocity, Cu-ZSM-5 is suggested as one of the strong candidates for catalysts applicable to lean-burn gasoline and diesel engines, though several problems such as durability to water and overheating remain to be solved.
Optimization of Multi-Modal Discrete Functions Using Genetic Algorithms
Authors: Pham D T , Yang Y
Published: February 2007

Four techniques are described which can help a genetic algorithm to locate multiple approximate solutions to a multi-modal optimization problem. These techniques are: fitness sharing, ‘eliminating’ identical solutions, ‘removing’ acceptable solutions from the reproduction cycle and applying heuristics to improve sub-standard solutions. Essentially, all of these techniques operate by encouraging genetic variety in the potential solution set. The preliminary design of a gearbox is presented as an example to illustrate the effectiveness of the proposed techniques.
Vehicle Safety—a Review for 1993
Authors: Neilson I D
Published: February 2007

The decreases in road accident casualties in Great Britain and other European countries should not obscure the likelihood that numbers will increase in the long term unless vehicle speeds are reduced at potential danger spots. There is also the need to take whatever safety measures are available. The Thirteenth International Experimental Safety Vehicles Conference in Paris at the end of 1991 provided an opportunity to review the technical progress that has recently been made towards improved vehicle safety measures. This paper attempts to review much of the work presented to the conference and to suggest the best way forward for many aspects of vehicle safety. These range from accident studies to developments in vehicle control and handling, protection for the legs of motorcyclists, the opportunity for introducing measures to protect pedestrians and the latest advances in the protection for car occupants. Overall the need is seen to develop vehicle safety measures rapidly to permit the introduction of environmental restrictions on vehicle fuel consumption and design without cancelling the advances being made in casualty reduction.
A Genetic Algorithm Based Preliminary Design System
Authors: Pham D T , Yang Y
Published: February 2007

The different stages in design are briefly discussed. Examples of previous research into automating the preliminary design stage are described. An architecture for a computer aided preliminary design system is proposed. A prototype system for generating design concepts for transmission devices is presented.
Real Evaluation of Thermal Comfort in the Car Passenger Compartment
Authors: Della Rolle C , Romitelli G F
Published: February 2007

Thermal comfort is in increasing demand from motorists bound to cover more mileage than ever before in car driving. As a result car makers are striving for improved climate conditions inside the car to meet passenger demand for more comfortable trips.

A crucial question arises: ‘How can such improved conditions be developed into a product, when a dynamic system capable of responding to customers' subjective sensations does not exist?’ They cannot be achieved through the conventional ‘robust design’ philosophy or the engineering shelf approach whose main targets are: product development from the design stages, a reduced lead time to market, the set-up of competitive products, as well as an ‘objective’ measurement of the end product performance. What is actually needed in designing satisfactory air conditioners is a dynamic simulation system capable of instantly monitoring ‘subjective’ sensations variously experienced by car passengers. To this end, a piece of gauging equipment was set up at Fiat to measure thermo fluid dynamic comfort conditions in real time, and trace back any local discomfort sources.

The manikin used for such tests was a valuable example of providing a measuring instrument to meet subjective customers' requirements. Such a dummy is normally employed in Fiat climatic wind tunnels to determine a comfort index according to standard specifications.

Reference limits were defined to correlate both experimental and test results with actual customers' requirements. Useful suggestions were also included to improve every sensor used throughout testing.
Generalized Theory of Brake Noise
Authors: Nishiwaki M
Published: February 2007

Eliminating brake noises generated during brake application is an important issue in the improvement of comfort in vehicles. Brake noises (frequency 1–15 kHz) are often called brake squeal. On the other hand, brake noises (frequency 200–500 Hz) are often called brake groan noise. The studies on drum brake squeal, disc brake squeal and disc brake groan noise have already been presented in references (2), (3) and (4), where theoretical analyses on these brake noises were described. This paper shows that the equations of motion are represented by the same type of equations. Based on these analyses. It is clear that drum brake squeal, disc squeal and disc brake groan noise are generated by the same cause—dynamic instability of the brake system with friction force variations.
Steady Flow Characterization of Tumble-Generating Four-Valve Cylinder Heads
Authors: Arcoumanis C , Hu Z , Whitelaw J H
Published: February 2007

A method to quantify the tumble-generating characteristics of cylinder heads under steady flow conditions has been developed and its validity confirmed by results in a motored engine. It is based on the design of a flow adaptor which transforms tumble into swirl, allowing conventional methods for characterizing swirl to be applied.
The importance of NO2 in Bench Tests for Precombustion Deposits in the Spark Ignition Engine Intake System
Authors: Chou T L , Priestman G H
Published: February 2007

Most previous laboratory-scale deposit simulator studies have considered mainly fuel or lubricant composition and properties, with no consideration of possible effects of NOx, which may affect initiation of the deposit formation process and the overall rate at which deposition occurs. In this study a laboratory-scale deposit simulator was developed which produced thin deposit films by spraying gasoline on to a heated aluminium sleeve to investigate the effects of temperature, NO2 and possible gasoline blending components, on deposit formation. The amount of deposit collected is indicative of the deposit-forming tendency of the test fuel. The deposit film composition was analysed using Fourier transform infrared (FTIR) spectroscopy.

The results of the experiments indicate that deposit formation is indeed sensitive to NO2, in addition to the effects of temperature and the molecular structure of the hydrocarbons. Thus the effect of NOx in deposit-related studies is important and should not be ignored. The FTIR analyses showed that when using NO2 the deposits are of a very similar structure to those produced in a real engine test. The analyses also gave some insight into the role of NO2 in the deposit formation mechanism.
Data Sources for Reliability Design Analysis
Authors: Moss T R , Strutt J E
Published: February 2007

Quantified reliability assessment is now employed by many organizations in the process industries. The objective is to identify critical areas in the plant where design changes are required to meet the safety or production specification. Mechanical system assessment is, however, frequently inhibited by the lack of representative equipment reliability data. Where these data are not available in-house recourse must be made to generic sources from the public domain. Members of the Process Industries Division's Mechanical Reliability Committee have recently completed a study to identify and evaluate the principal reliability data sources for use in process system assessments. This paper discusses the data requirements for reliability assessment and the use of these generic data to provide best-estimates of the reliability statistics for specific applications.
Stochastic Decisions in Engineering Design
Authors: Simmons P E
Published: February 2007

In this paper the author has attempted to show how the quality of some engineering design decisions can be improved by the use of reliability engineering and other statistical techniques.
Identification of Support Conditions of Buried Pipes Using a Vibrating Pig
Authors: Köpke U G , Hunt H E M
Published: February 2007

This paper describes a method for monitoring the variation in support condition of pipelines using a vibration technique. The method is useful for detecting poor support of buried pipelines and for detecting spanning and depth of cover in sub-sea lines. Variation in the pipe support condition leads to increased likelihood of pipe damage. Under roadways, poorly supported pipe may be damaged by vehicle loading. At sea, spanned sections of pipe are vulnerable to ocean current loading and also to snagging by stray anchors in shallow waters.

A vibrating ‘pig’ has been developed and tested on buried pipelines. Certain features of pipe support, such as voids and hard spots, display characteristic responses to vibration, and these are measured by the vibrating pig. Post-processing of the measured vibration data is used to produce a graphical representation of the pipeline support and certain ‘feature characteristics’ are identified. In field tests on a pipeline with deliberately constructed support faults, features detected by the vibrating pig are in good agreement with the known construction.
Magnetic Filtration of Fine Particles from Gas Streams
Authors: Lua A C , Boucher R F
Published: February 2007

Dust particles from the basic oxygen furnace steelmaking process were removed from air streams using a laboratory high-gradient magnetic filter. Particle sizes and number concentrations were determined by an optical particle spectrometer and were found to be largely in the submicrometre range. Dust loadability increased greatly when a magnetic field was applied and showed no deterioration in filter performance, even though the matrix had captured 10 times its own volume of dust. Particle penetrations of 1 per cent and less were achieved for submicrometre particles down to an optically measurable 0.24 μm diameter. Varying only one parameter at a time has isolated the individual effects of filter length, magnetic field, matrix packing fraction, gas velocity and wire size and aspect ratio. The dimensionless groups in an idealized single-wire model for high-gradient magnetic filtration are not adequate for a real filter. Other dimensionless parameters, viz. average dimensionless wire separation and cumulative dimensionless wire blockage, arise and are found to be important.
A Study of Flow Downstream of a T-Junction and the Implications of its Effect (In Crude Oil Flow) on Water Droplet Size and Distribution
Authors: Lenn C P , Hemp J , Baker R C , Hayes E R , Harper A D
Published: February 2007

A laser Doppler anemometer (LDA) is used to measure velocity profiles and turbulence levels of water flow in the first few diameters downstream of a T-junction. The ‘vertical’ limb of the T-junction is half the diameter of the ‘horizontal’ limb, one end of which is blanked off. Flow passes from the smaller into the larger tube and LDA measurements of axial and tangential velocity components are conducted in the larger tube up to 3.75 diameters downstream of the T-junction at Reynolds numbers of 10.5 × 104 and 7.42 × 104. The pipe geometry is a commonly occurring configuration in crude oil pipelines and is of interest because of its possible ability to break up and mix water droplets to an extent sufficient for accurate grab sampling. LDA measurements of r.m.s. velocity fluctuations give information on the level of turbulent diffusivity and hence the maximum size of droplets that can be present in crude oil flow in the same geometry. A novel mathematical technique is used to interpolate between LDA measurements of mean velocity and to calculate the radial component of mean velocity. The three-dimensional velocity distributions thus formulated are used to predict water droplet concentration profiles downstream of the T-junction using the Segev approach—that is by solving numerically a differential equation for concentration of a contaminant under conditions of turbulent diffusion. Results are compared with field measurements in a similar geometry.
Management of In-Service Inspection of Pressure Systems—A Report on Two Conferences
Authors: Crooks E
Published: February 2007

An international conference on ‘Management of in-service inspection of pressure systems’ was held in London on 9–10 March 1993
Railway Air Brake Simulation: An Empirical Approach
Authors: Murtaza M A
Published: February 2007

This paper deals with the railway air brake simulation by using empirical equations. These empirical equations have been developed from an analysis of predictions of theoretical brake models. They are simple and can be used for quick predictions as the number of computations has come down drastically. Various non-dimensional quantities have been used which make it a general approach.
Partners—In Crime
Authors: Roche A D
Published: February 2007

Britain's railways stand at the threshold of the biggest change that has been seen for half a century. The author's theme is the impact of engineering and organizational changes on people in the railway industry. The management of this change demands understanding of the technology being applied, as well as the changes in practice and behaviour which are needed for it to be successful. The author relates these issues to the people he has worked with throughout his career and the changes he has experienced.
Development and Application of Auto-Coupler Systems for a Steelworks 1988–92
Authors: Bentley P H
Published: February 2007

The paper describes the development of specialized couplings to suit the steelworks application, which together with the introduction of radio-controlled locomotives and electrically operated points, has achieved significant manning reductions at the British Steel Teesside Works.
Crack Analysis using Discontinuous Boundary Elements
Authors: Elzein A , Adey R A
Published: February 2007

A simple and efficient approach is proposed for the analysis of crack problems occurring in mechanical components widely used in the aerospace industry. A linear stress analysis of the cracked components is performed using discontinuous boundary elements at the crack tip. The engineering analysis system BEASY is used to derive accurate predictions of the stress intensity factors corresponding to either of the three modes KI, KII or KIII. With the proposed approach, the user has to model only the surface of the component, as opposed to its volume in finite elements. Thus, line elements in two-dimensional and axisymmetric problems and surface quadrilaterals or triangles in three-dimensional problems are used to mesh the components. The approach clearly results in substantial savings in mesh preparation effort. The paper will describe the application of the system to problems in the aerospace field and the convergence results that demonstrate the high accuracy and reliability of the technique.
Effect of the Baffle on the Asymmetric Gravity-Jitter Excited Slosh Wave and Spacecraft Moment and Angular Momentum Fluctuations
Authors: Hung R J , Lee C C , Leslie F W
Published: February 2007

The dynamic behaviour of fluids affected by asymmetric gravity jitter oscillations, in particular the effect of surface tension on partially-filled rotating fluids in a dewar tank, with and without installing baffle-board, imposed by time-dependent directions of background gravity have been investigated. Results show that lower frequency gravity jitter imposed on the time-dependent variations of the direction of background gravity induced a greater amplitude of oscillations and a stronger degree of asymmetry in liquid–vapour interface geometry than that made by the higher frequency gravity jitter. As the viscous force, between liquid and solid interface, greatly contributes to the damping effect of slosh wave excitation, a rotating dewar installed with baffles provides more area of liquid-solid interface than a rotating dewar without baffles. Results show that the damping effect provided by the baffles reduce the amplitude of slosh wave excitation, lowers the degree of asymmetry in the liquid–vapour distribution, and lowers angular momentum and fluid moment fluctuations.
The Use of Hot Films for Investigation of Boundary-Layer Transition
Authors: Gaudet L , Betts C J , Ashill P R
Published: February 2007

The constant temperature hot-film technique has been used to investigate the transition region on a modified flat plate and a large two-dimensional wing. Time histories and r.m.s. values of the output signals together with the power spectral density (PSD) clearly indicate the build up of energy associated with the development of Tollmien–Schlichting waves prior to the onset of transition. A large increase in the low-frequency energy content of the spectrum occurs at the onset of transition. Measurements of skin friction through the transition region have been obtained based on the mean heat loss of the hot film.
Computer Modelling of Aircraft Hydraulic Systems Using Bathfp
Authors: Tomlinson S P , Tilley D G
Published: February 2007

The computer simulation package BATHfp has been developed at the Fluid Power Centre, University of Bath to perform transient time domain simulations of fluid power systems. Utilities are provided which allow new models to be introduced into the component database. This enables the package to be tailored to particular dedicated areas of interest such as aircraft flight controls, braking and landing gear and fuel flow systems. This paper describes the application of BATHfp to aircraft hydraulic systems. An example is taken of an electrohydraulic position control system which uses an actuator to move an aileron according to a desired schedule. Parametric variations are made to illustrate how system performance can be improved.