bluuebunny/crossref_metadata_2025_split huggingface dataset:
Manufacturing Strategies from Concept to Realization
Authors: Wallis J 
Published: February 2007

GEC is one of the major manufacturing companies in the United Kingdom with sales to customers outside the Group of £D5553 millions in 1987–8, of which £D1232 millions were exports. Little is known about GEC's huge manufacturing capability. Somewhere in the organization, practically every piece of new technology is employed. Radical changes are constantly taking place. Every manufacturing development is designed to meet the requirements of the business which it is to serve. This paper demonstrates success from matching manufacturing achievements to business needs. Examples will be taken from some of the more mature businesses within GEC where the sceptics may say that change is difficult to accomplish.
A Major Advance in the Manufacture of Large Structural Beams and Columns
Authors: Walker J H , Walpole L B 
Published: February 2007

This paper describes the enhancement project undertaken at British Steel's Teesside Works which enabled the Universal Beam Mill to become the first such mill in the Western World to introduce the use of continuously cast slabs as the feedstock for rolling heavy beams and columns. The change necessitated construction of a new slab reheating furnace, a complete modification of mill rolling practice and involved several engineering developments needed to enable the new process to be successfully integrated within the existing plant. The new process has resulted in significant benefits for the mill's customers and has greatly improved mill performance through a reduction in material yield losses, higher output speeds and improved plant availability.
Modified Independent Modal Space Control Method for Active Control of Flexible Systems
Authors: Baz A , Poh S , Studer P 
Published: February 2007

A modified independent modal space control (MIMSC) method is developed for designing active vibration control systems for large flexible structures. The method accounts for the interaction between the controlled and residual modes. It also incorporates optimal placement procedures for selecting the optimal locations of the actuators in the structure in order to minimize the structural vibrations as well as the actuation effort. The MIMSC method relies on an important feature which is based on ‘time sharing’ of a small number of actuators, in the modal space, to control effectively a large number of modes. Numerical examples are presented to illustrate the application of the method to generic flexible systems. The obtained results suggest the potential of the devised method in designing efficient active control systems for large flexible structures.
Simulation of the Pressure Ripple Characteristics of Hydraulic Circuits
Authors: Johnston D N , Edge K A 
Published: February 2007

The pressure ripple in a hydraulic circuit is commonly a major source of noise. A computer program has been written to simulate the pressure ripple characteristics of hydraulic circuits and to aid in the design of low noise circuits. Mathematical models of flexible hose and of pump flow ripple and source impedance have been developed. Validation tests on various circuits show that the program produces good correlation with experimental measurements. A simple silencer consisting of an asymmetric pipe loop, known as a Quincke tube, was analysed. Its performance was shown to be limited, providing attenuation over very narrow bandwidths.
The Development of a Direct Injection Diesel Combustion System for Low Noise, Emissions and Mechanical Loading
Authors: Jane P A H , Brear F 
Published: February 2007

In recent years the whole climate of diesel engine development has changed with the advent of noise and emissions legislation combined with the demand for higher specific output. The conventional direct injection combustion chambers that have been used in the 1 litre/cylinder class of engine now present difficulties to the engineer in meeting these increasingly stringent demands. The development history of a novel combustion system, ‘Quadram’, is presented, leading up to its introduction into quantity production. Emphasis has been placed on achieving the legislative targets while retaining cost effective fuel injection equipment, in an intensely competitive market complicated by worldwide fuel quality variations. The ‘Quadram’ system is shown to display the key feature of achieving optimum performance with retarded injection timing, without any compromise to engine durability.
A Supervisory Grid to Understand the Role of the Maintenance Foreman in Process Industries
Authors: Riddell H S 
Published: February 2007

The maintenance foreman occupies a critical role in a process industry. He is at the focus of two strong, sometimes conflicting, sets of influences, top-down from senior management, and bottom-up from the maintenance workload and tradesmen. It is a complex and ambiguous role both to the foremen themselves and to their managers. This paper explains why such ambiguity is likely to arise. A novel matrix is developed comprising four key interrelated domains of the maintenance foreman's role, and into which all the duties he is normally expected to perform can be categorized. The resulting supervisory grid clarifies both the wide scope of these duties, and identifies the two differing personal characteristics which maintenance foremen require in order to succeed in performing them. The grid has many practical applications. In particular it provides a sound basis for examining the new specialist and diversified roles for maintenance foremen which are now emerging in the process industry.
Vibration Monitoring of the Internal Centreless Grinding Process Part 1: Mathematical Models
Authors: Lacey S J 
Published: February 2007

The grinding process is complex with many interrelated parameters, and an initially stable process can become unstable as grinding conditions naturally deteriorate. Forced vibration from machine rotating elements and self-excited vibration produce a relative radial movement between the wheel and workpiece during grinding and the wheel and diamond during dressing, causing errors in workpiece finish and form. By monitoring vibration produced during the grinding and wheel dressing operations a measure of expected workpiece quality can be obtained. In order to use vibration monitoring effectively as a means of detecting adverse grinding and dressing conditions it is necessary to gain an insight into the dynamics of the process so that relevant parameters for monitoring are identified. In Part 1 of this paper, with the aid of simple models, the different types of vibration that can occur during the grinding and dressing operations are identified, along with their likely effect on workpiece quality.
Squeeze-Film Damping of the Motion of a Control Flapper-Nozzle
Authors: Akers A , Lin S-C J 
Published: February 2007

A squeeze film used in a flapper-nozzle affords stand-alone properties to the flapper motion, meaning that it behaves in a dynamically stable manner. The device constitutes the first stage of a new family of two-stage electrohydraulic control valves. Successful mathematical modelling of it has been reported by Lin and Akers (1,2). Because of the expense of maintaining close manufacturing tolerances within the damper, the investigation included the extent of deterioration of dynamic response when the dimensions of the damper are varied, when the tolerances on the squeeze-film annular area are relaxed and when the annular clearance is increased. As a result of the investigation, the dimensions and other variables, chosen by trial-and-error procedures, appeared to be optimum from the point of view of dynamic performance, convenience of installation and cost.
Influence of the Blade Stacking on the Flow Through an Axial Flow Runner and Predictions of Three-Dimensional and Quasi Three-Dimensional Numerical Codes
Authors: Ardizzon G , Pavesi G 
Published: February 2007

The influence of the stacking of the blade sections on the flow through an axial flow runner is investigated by means of quasi and three-dimensional finite element programs. The results show up higher pressure gradients close to the leading edges, in the sections near the hub, when the stacking point is displaced towards the trailing edge. These gradients become noticeable near the trailing edge when the stacking point moves towards the inlet, even if in an attenuated way these trends reverse in sections close to the shroud. The above-mentioned effects are highlighted only if three-dimensional codes or quasi three-dimensional codes with more than one hub-to-shroud surface are employed.
Improved Cam Profiles for High-Speed Machinery Using Polynomial Curve Fitting
Authors: Sadek K S H , Daadbin A 
Published: February 2007

Traditionally, cams are designed using standard curves of harmonic, cycloidal and parabolic functions, which are applied to certain intervals of the cam cycle. In fact it is the discontinuity in the acceleration diagrams of these cams which produces the high harmonics of the running speed and makes them unsuitable for high-speed applications. Using polynomial curve fitting for the acceleration diagram, one of these cams is smoothed down in such a way that the deviation from the initial lift diagram is minimal. The profile produced is shown to have far fewer harmonics. Furthermore, when the profile was tested using a two-degree-of-freedom model it was shown that the vibration of the mechanism and its tendency to bouncing were reduced significantly.
Testing of Total Hip Replacements: Endurance Tests and Stress Measurements: Part 2: Stress Measurements
Authors: Humphreys P K , Orr J F , Bahrani A S 
Published: February 2007

Brittle lacquer techniques and electric resistance strain gauge rosettes were used to measure strains on the stems of total hip replacements while loaded according to three standards. The stresses in these locations were also calculated and good agreement was found between the measured and calculated values. The Sines equation was used to calculate the endurance limit stress. Again good agreement was found with observed results. Suggestions are made regarding the endurance testing of hip prostheses.
A Comprehensive Classification of Combined Cycle and Cogeneration Plant: Part 1: Presenting the Map of Turbomachinery Options for Heat and Power
Authors: Taft M 
Published: February 2007

An overall picture of combined gas and steam cycle options, without dependence on numerical analysis, is long overdue. A single equation is derived for plant thermal efficiency. This is based upon component efficiencies and the ratio of steam plant size to gas turbine size. Therefore, a unique map can be graphically presented covering the whole steam range from power generation through to cogeneration (that is combined heat and power) in association with gas turbines. Understanding of the map leads to recognition of an underutilized area. The gas turbine is normally integrated with the main steam boiler. Conversely, the unfixed combined cycle plant may be integrated with a conventional boiler and back-pressure turbine. The correct steam turbine-gas turbine size ratio must be chosen. A practical example is given of how a gas turbine and waste heat boiler may be introduced part-way along a large power station's main steam turbine. The integration is achieved in the steam cycle and not at the main boiler. This approach allows low-risk, low capital cost, simple repowering of large power stations. It is not a new thermodynamic cycle, but has the following advantages: 1. The tie between the extent of after-firing and waste heat boiler efficiency is avoided. The conventional boiler is fired and the waste heat boiler is unfired. Integration of the plant occurs at the intermediate pressure level of the steam turbine. 2. The above integration gives high thermal efficiency. It also retains the conventional boiler, or equivalent, which is free to burn a range of fuels. 3. The gas turbine waste heat boilers and the main boiler together fill a common steam turbine of an economic size. Two types of plant are considered to demonstrate the practical usefulness of the integrated steam cycle. Examples are given based on coal-fired, or heavy-fuel-oil-fired combined cycle plant, integrating conventional boiler, gas turbine plus unfired boiler and steam turbine. The data are based on real equipment, which is either at existing UK installations or plant of known performance. An explicit analysis is also presented to compare fuel running costs for the integrated steam cycle with costs for both unfired combined cycle plant and conventional steam plant.
Nett Energy Flow Analysis—Constraints on the Growth Rate of Power Station Construction Programmes
Authors: Hill R 
Published: February 2007

The construction of all energy supply devices requires an energy input. The intensive programmes of construction of non-fossil-fuel power stations which some have proposed to alleviate carbon dioxide emissions from electricity generation would require a substantial energy input. It is shown in this analysis that the nett energy available to society, that is the energy generated minus the energy needed for construction, is critically dependent on the growth rate of the construction programme. All construction programmes are initially nett users of energy, but a rapidly expanding programme of construction can lead to a nett deficit of socially available energy for 20 years or more, and under some circumstances the entire construction programme can be a nett user of energy. In particular, it is shown that a programme of construction of nuclear power stations to replace existing coal-fired stations and meet an expanding demand for electricity would produce a nett energy deficit until well into the next century. There would be no possibility of scrapping existing coal-fired power stations until about 20 years after the beginning of the construction programme.
A Simple and Realistic Model for the Scavenging Process in a Crankcase-Scavenged Two-Stroke Cycle Engine
Authors: Sher E , Harari R 
Published: February 2007

A semi-empirical model for the scavenging process in a crankcase-scavenged two-stroke cycle engine is proposed. The model is based on the assumption that, typically, the time variation profile of the exhaust gas purity, β, exhibits a sigmoid-type curve while a rounded protuberance usually appears on its back, thus forming a ‘crest’ profile. The hump has been interpreted as the occurrence of an extensive short-circuiting. An exponential function of the form of is suggested to fit this curve, from which the scavenging efficiency has been derived. Two parameters, namely the mixing degree, b, and the short-circuiting degree, c, are to be calibrated. However, it was found that the selection of the best fitting values for b and c do not depend on the engine speed or on the engine load. Rather, b and c are inherent properties of the engine design. For modern engine design a value of 0.57 is recommended for b and a value of 0.81 for c/c-max. Calculations of the scavenging efficiency were found to be in excellent agreement with predictions of a detailed computer program for three small Schnürle-type different make engines. The present model does not consider a specific mechanism for the gas exchange process, and as such it is believed that it is applicable to other engine types (cross, loop or uniflow) to the same extent.
Deviation in a Mixed Flow Fan
Authors: Matthews R D , Gasiorek J M , Cavanagh J 
Published: February 2007

A simple empirical method for calculating the total deviation in mixed flow impellers is proposed. Data are presented which show that the total deviation can be modelled by the superposition of a viscous deviation, related to the blade cascade performance, and an inviscid deviation, due to a secondary flow in the blade passages. Measured values of total deviation are given together with details of the inviscid secondary flow model. The viscous deviation component is shown to be a function of the modified blade loading parameter used in the correlation of cascade data.
Response of Bulk Flowmeters to Multiphase Flows
Authors: Baker Roger C 
Published: February 2007

This review has attempted to select the most recent references with the most useful data. It does not cover local velocity measurements or related parametric measurements. The nature of multiphase and multi-component flow is briefly considered. Data on existing flowmeter designs in two-component flow suggest that the most likely contenders for fiscal measurement precision are venturi, positive displacement, electromagnetic and correlation flowmeters. There are inadequate data so far to determine the eventual usefulness of the Coriolis mass flowmeter. Flowmeter combinations of volume and momentum sensing have been used to deduce mass flow, as have combinations of volume flowmeter and densitometer. Major systems under development incorporate many sensors to measure both combined and separated flows. The discussion section seeks to give a general insight into the topic and the associated problems by identifying common themes across a number of meters. Various topics are discussed which relate to the problem of precise multi-component flow measurement: what to measure; gas entrapment; ancillary equipment; dynamic modelling; damage; physical effects; whether to separate the components; the need for calibration. The review concludes by identifying future areas where academe and industry can contribute, particularly if they do so collaboratively.
Thermal Effects and Pressure Distributions in Brakes
Authors: Day A J , Tirovic M , Newcomb T P 
Published: February 2007

Heat generated at the sliding interface between the friction material and the mating surface of a friction brake is not uniformly distributed over the sliding surfaces but depends upon the local interface pressure. Many thermal problems associated with brake friction pairs, including performance variation (fade, speed sensitivity) and rotor damage (heat spotting and thermal cracking) can be analysed in terms of localized frictional heat generation as discussed here. This paper describes how the thermal effects of interface pressure distribution may be divided into bulk temperature effects, such as brake drum expansion and brake disc coning, and its macroscopic thermal effects, such as heat spotting, and suggests how the two are related through the process of thermoelastic instability. The results of analyses, using finite element methods, indicate that uniform friction interface pressure is very important in minimizing brake thermal problems. However, more basic research in the area of interface contact and pressure distribution, and frictional heat generation and dissipation, still remains to be done in order to understand fully the role played by each part of the friction pair in thermally related braking problems.
A Note on the Design of Air Springs
Authors: Agnew B 
Published: February 2007

The geometry of the shell of an air spring is examined and it is shown that it can be described in a plane of symmetry by the following equation cast in the XY plane: The error in calculating the stress in the shell, assuming it to be of spherical form, is determined and it is shown that the error can be small if care is taken with the geometric design of the spring.
A Lightweight Hydrocarbon Sample Vessel
Authors: Murphy P V 
Published: February 2007

Existing stainless steel hydrocarbon sample vessels were heavy and sometimes suffered corrosion problems. There was a need to redesign in an alternative material that would meet the requirements for pressure, temperature, weight, corrosion resistance, availability and cost. A materials survey led to titanium 318 being chosen. The redesign took full account of the different properties of the new material, particularly its relatively low stiffness. Following detailed discussions with the material supplier and the manufacturer, prototype vessels were designed, manufactured and tested successfully. This led to the production of many more sample vessels, and an increased use of titanium 318 for other pressure vessels.
The new Pressure Systems and Transportable Gas Containers Regulations: Part 1: Inspection Procedures to Meet the Regulations
Authors: Towndrow R F R , Groome R D 
Published: February 2007

In preparation for the coming into force of the Pressure Systems and Transportable Gas Containers Regulations (1989), two Seminars were sponsored in May and June 1990 by the Process Industries Division, North West Centre, and the Pressure Systems Group of the Institution of Mechanical Engineers. New ground is broken in the Regulations in the primary duty of compliance being placed on the users of fixed pressurized systems. Mr Towndrow's paper (Part 1) describes already proven engineering management and control procedures that meet the user's new responsibilities and outlines further changes required during the four year lead-in programme. The scope of the legislation for gas cylinders has been greatly extended in variety, size and new technology. Dr Irani's paper (Part 2) traces the improvement in cylinders, and draws attention to new procedures on filling, rerating and repairs. He demonstrates the contribution of British Standards to gas cylinder development and anticipates the Regulations forming a valuable input to the proposed European Directive currently being drafted. The Pressure Systems and Transportable Gas Containers Regulations (1989) provide a legal framework for many of the existing voluntary procedures in the process industries. The presentation outlines how ICI's inspection procedures have evolved in recent years, and how they will be able to meet the requirements of the new legislation. While designed primarily for an in-house inspection organization, they are also applicable where a third party inspectorate provides the inspection service to particular works.
A Model of Force Transmission in the Tibio-Femoral Contact Incorporating Fluid and Mixtures
Authors: Schreppers G J M A , Sauren A A H J , Huson A 
Published: February 2007

An axisymmetric finite element model is formulated which comprises a rigid spherical indentor, a meniscal ring and an articular cartilage layer, both considered as mixture materials which are interacting with an ideal fluid sub-system. From parameter studies it is concluded that the application of the mixture theory in comparison with solid modelling only leads to significant effects when the outer surfaces of the components are not sealed. The load distribution appears to change enormously during relaxation of the models. Initially the largest fraction of the load is borne by the fluid in the cavity, while at the end, when the system has reached its final configuration, the meniscal ring bears the major part of the load. Further, the length of the relaxation period appears to depend on the magnitude of the step change of the load. Finally, the curvature of the spherical indentor appears to have significant effects on the loading of the meniscal ring, only immediately after the step changes of load are applied, and these effects disappear as soon as the fluid starts to exude from the models.