bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effects of Projectile Speed and Medium Resistance in Ricochet off Sand
Authors: Baif Y. L. , Johnson W. 
Published: February 2007

It has been observed experimentally that when a sphere ricochets off water or sand the critical impact angle depends on the impinging velocity. To explain this, a model is developed which takes into account the weight of the sphere and the static resistance of the medium into which penetration occurs. The proposed model can also treat processes in which the angle of impact is large and where the velocity of the sphere undergoes considerable change. Projectile trajectories which have been calculated for various conditions are presented and discussed. Numerical results for steel, aluminium alloy, and lead spheres are in good agreement with such experimental results as are available.
A Study of Diffuser/Rotor Interaction in a Centrifugal Compressor
Authors: Fisher E. H. , Inoue M. 
Published: February 2007

Experimental flow data recorded on a low speed centrifugal compressor rig are compared with theoretical predictions of the diffuser field. Results for four diffuser geometries are presented covering variation of the blade number, stagger angle, and radial separation of the rotor and diffuser. The theoretical predictions are based on an extension of the Martensen surface singularity theory. The diffuser is found to play a major role in establishing the circumferential variation in the mean flow at impeller outlet. Large pitch wise variations are observed, which may be explained by consideration of the flow round the leading edges of the diffuser blades. Experiments and potential flow theory show good agreement, except for cases where the diffuser shows signs of separation. These are clearly identified from the theoretical predictions by Carter's lift coefficient criterion. Although the absolute flow at rotor outlet is markedly time-dependent owing to the passage of the rotor, it would appear that the averaged flow conditions may be predicted by the steady-state singularity program. Unstalled diffuser flows are accurately predicted and stalled flows, which are generally to be avoided, may be anticipated from the lift coefficient criterion. The designer thus has the option of reducing pitchwise velocity and pressure variations at rotor outlet to acceptable amplitudes.
A Novel Technique of wire Drawing
Authors: Hashmi M. S. J. , Symmons G. R. , Parvinmehr H. 
Published: February 2007

In the conventional wire drawing process the reduction is achieved by pulling the wire through a tapered die. The minimum bore size of such a die is always smaller than the inlet wire diameter. A suitable lubricant is used to reduce the die wear and drawing load and to produce a good surface finish. Nevertheless, the problem of die wear and wire breakage during start-up is always present. In this paper a new technique of wire drawing is being reported which eliminates the problem of wear and breakage during start-up and also the need to have the diameter of the leading end of the wire reduced for easy insertion through the die. The reduction of the wire diameter is affected by means of the hydrodynamic action of a polymer melt lubricant in conjunction with a long tapering tube, the diameter of the tube being greater than the nominal wire diameter. Reductions in area of up to 21 per cent can be obtained in one single pass using this dieless reduction unit.
The Dynamic Response of Railway Track to High Frequency Longitudinal Excitation
Authors: Grassie S. L. , Gregory R. W. , Johnson K. L. 
Published: February 2007

The dynamic response of railway track to longitudinal forces is investigated. A model is presented of the rail as a uniform infinite bar resting on a continuous support. There is good agreement in the frequency range 50–1500 Hz between experimental data and the response calculated using this model. The support is significant up to a frequency of about 200 Hz, above which the rail is effectively a dashpot. The discrete nature of the support on sleepers is relatively unimportant. The track moves very much less under longitudinal forces than it does under vertical forces at these frequencies.
Effect of Surface Roughness on the Squeeze Film between Rotating Porous Annular Discs
Authors: Prakash J. , Tiwari K. 
Published: February 2007

The analysis of the squeeze film between two rotating annular discs, one with a porous facing is extended to include the effect of surface roughness. A detailed study of the squeeze film characteristics for a wide range of operating parameters is made to illustrate the effect of rotation and surface roughness and their interaction.
The Role of Research in Man's Use of the Oceans
Authors: Adye A M 
Published: February 2007

The contribution of research towards innovation and growth in ocean-related activities over past centuries is explored through a number of case studies. This historic view is amplified by some of the author's own experiences relating to the more recent development of offshore oil and gas resources. Some implications from recent and current research programmes and scientific experiments are reviewed in an attempt to identify possible pointers towards future changes and developments in ocean-going operations. The paper examines the motivation, organization and shaping of some current research activities, and concludes with some suggestions directed towards enhancing the national research effort and its potential contribution towards economic and responsible development of the oceans.
Performance Characteristics of Centrifugal Pumps When Handling Non-Newtonian Homogeneous Slurries
Authors: Walker C I , Goulas A 
Published: February 2007

The change in performance characteristics of centrifugal pumps when handling fine granular or homogeneous type non-Newtonian slurries has been investigated using two different slurry pumps handling mixtures of coal/water and kaolin/water. A test loop was used which allowed pump performance to be determined at various pump speeds, with many different mixture concentrations and rheologies. The test work indicated two main changes in the pump performance compared to the water characteristics: (i) a large drop in pump developed head at low flowrates (creating an unstable curve), and; (ii) a reduction in the pump efficiency at flowrates near the best efficiency point. The results show that the pump performance is dependent on the slurry's rheological properties, with pump Reynolds number giving generally good correlation with the change in performance. Methods of performance correlation used for Newtonian fluids were found to give good results provided that a suitable value for the viscosity could be chosen.
Radioisotope Techniques for Problem-Solving in the Chemical Industry
Authors: Charlton J S 
Published: February 2007

Radioactive isotope techniques are now being applied routinely to the study of a wide range of problems on industrial process plant. The expansion of these activities has been stimulated both by the comparative ease with which measurement can be carried out on full-scale plant and by the ability of radioisotope techniques to diagnose plant faults while the plant is still on-line. This latter attribute can result in substantial economic benefits in terms of saved down-time. This paper reviews the ways in which radioisotopes are used by ICI to solve problems on large-scale process plants. Recognizing that the field of application is extremely wide attention has been concentrated upon those techniques which have been found to be of greatest use. This selection is made on the basis of the work spectrum of ICI's Physics and Radioisotope Services, an organization which each year carries out more than 1500 applications for customers both within and external to ICI. The techniques described fall into two major categories: sealed source techniques and methods involving radioactive tracers. Applications from each category are described and, where appropriate, indications of the resulting economic benefits are given.
Experience Gained in Constructing and Commissioning Two Medium Sized Wind Turbines
Authors: Wilson R R , Brown A 
Published: February 2007

James Howden have designed a 300 kW wind turbine specifically for use in isolated sites, with the first such machine being installed on Burgar Hill, Orkney. The Company were also responsible for supplying the Central Electricity Generating Board (CEGB) with an American design of wind turbine; this is the 250 kW machine which has been installed at Carmarthen Bay, Wales. This paper outlines the design features of these two wind turbines and describes the difficulties encountered and the lessons learned in constructing and commissioning the machines.
A Study of Highly Turbocharged High-Speed Diesel Engines
Authors: Charlton S J 
Published: February 2007

The paper discusses the potential of a conventional high-speed diesel engine for operation at increased power output (+ 50 per cent), using readily available components and ancillaries, whilst retaining the traditional virtues of good thermal efficiency, ruggedness and low cost. The baseline engine was turbocharged and intercooled having a maximum b.m.e.p. of 14 bar at 1500 r/min. The research engine was designed for, and operated at a b.m.e.p. of 21 bar at the same speed. The results of a computer simulation and extensive experimental programme using an 11 litre in-line six-cylinder engine are presented. The project demonstrates the contribution that computer modelling may make to the design of turbocharged engines, making possible a considerable reduction of the costly development phase. The effects of compression ratio, valve timing, fuel injection and turbocharger match on performance and mechanical and thermal hading are discussed. Although extended durability testing was beyond the scope of the project, piston, cylinder head and valve temperature measurements show that metal temperatures were within accepted limits. The thermal efficiency of the research unit was consistently within the range 37–38.5 per cent at the target power output, which compares well with the baseline engine.
Computer Aided Layout of Metal Stamping Blanks
Authors: Nee A Y C 
Published: February 2007

In a metal stamping operation, the major cost is that of materials; any efforts during the design stage to minimize scrap by selecting interlocking figures or by using careful layouts may result in substantial savings. A number of template layout solutions has been developed but most of the methods require rather lengthy computation time even on a large computer. In addition, the solutions are not particularly geared towards metal stamping operations. This paper presents a simplified heuristic solution of nesting metal stamping blanks with near optimum layouts. A complete analysis, including press capacity, coiled or strip stock, cost analysis etc. is also suggested.
Digital Computer Simulation as an Aid in Improving the Performance of Positive Displacement Pumps with Self-Acting Valves
Authors: Edge K A , Brett P N , Leahy J C 
Published: February 2007

There is significant and growing demand for pumps with self-acting valves capable of handling water and water-based fluids. This paper describes a study performed on an eight cylinder radial piston diaphragm pump designed for water-based fluid operation. Pumping dynamics have been modelled by digital computer simulation and the results compared with those obtained from an extensive experimental programme. By means of simulation it has been possible to examine the effects of modifications to the original design. The influence of valve mass, lift, and valve seating springs on volumetric efficiency are presented. Delivery manifold pressure fluctuations are predicted using the method of characteristics taking into consideration the configuration and size of the manifold. These predictions are compared with experimental results. A modular approach has been adopted in the development of the model and as a result it may be readily adapted to suit a wide range of pumps employing self-acting valves.
A Method of Predicting the Effect of the Dissolved Gas Content of Water on Cavitation Inception
Authors: Naylor P , Millward A 
Published: February 2007

A technique has been developed which allows the effect on the cavitation inception number of the gas content in the water to be predicted in cavitation experiments. The predicted results have been compared with data obtained during experiments to measure cavitation inception in the tip vortex of a low aspect ratio hydrofoil and have shown good agreement. The results showed that the gas content affected the cavitation inception number significantly at low free stream speeds, particularly below about 4 m/s.
Methods of Taking Samples from Engineering Components for Mechanical Testing—Particularly Remanent Life Assessment
Authors: Barraclough D R 
Published: February 2007

Sampling of engineering components to produce mechanical test specimens has recently been used increasingly for post exposure stress rupture testing. In order to obtain a sufficiently large test piece, it is often necessary to remove so much material that the excavated component requires a weld repair before continuing service. Such a repair can necessitate post weld heat treatment, which may be too time consuming for critical plant. A requirement was to design and produce a method of taking small samples, without the need for weld repair of the component, by appropriate consideration of design and stress analysis criteria. This paper reviews some current sampling methods for producing multiple specimens. Large samples can conveniently be taken by trepanning a full thickness plug, followed by a weld repair. Small samples can be obtained by a new jig, using the chain drilling principle, by joining a series of 3 mm diameter holes, leaving a small excavation requiring only blending out. Various jigs are available to produce samples for gauge diameters up to 15 mm. Very small samples can also be obtained by small, hand held cutting wheels, but these are only adequate to provide metallographic specimens. Maximum benefit can be gained from the small samples by using them to produce specimen gauge diameters by welding on specimens’ ends. A procedure using electron beam welding has been developed and its initial application to stress rupture of test specimens is reported. The overall procedure from initial sampling to a post exposure stress rupture programme is outlined and typical current costs are given. Total site and testing cost can be below £5000 and it offers a cost effective route to quantify an extended creep life beyond the design minimum.
Non-Destructive Testing of Mass Produced Components by Natural Frequency Measurements
Authors: Cawley P 
Published: February 2007

Vibrations in engineering components may be excited by a light tap and the vibration response may be measured with a microphone and displayed as a frequency spectrum from which the natural frequencies of the component can be extracted. Changes in the natural frequencies of the various modes are observed when small defects such as cracks are present. The use of this technique for the production quality control of mass produced components has been investigated. Tests have been carried out on a cantilever beam, a piston-shaped component and a pulley wheel. It has been shown that, in the absence of dimensional variations, defects removing between 0.5 and 2 per cent of the cross-sectional area of the component at a single section may be detected, the precise size depending on the geometry of the component and the location of the defect. Dimensional variations reduce this sensitivity, but a method has been developed for correcting the results for dimensional changes, without the need for more measurements to be taken. The results show that, unless the likely location of a defect is known in advance, it is essential to measure the natural frequencies of more than one mode of vibration. The test takes less than ten seconds to set up, about one second to carry out and is amenable to automation.
The Updating of Engineers—Improved Profitability or Just More Courses?
Authors: Cannell R L 
Published: February 2007

The purposes of updating are seen as fa) improving job performance, (b) developing the country's engineering manpower, and (c) increasing job satisfaction. This leads to the actions which can be taken by employers, individuals, government and professional institutions, as well as consideration of the part being played by the Engineering Council. The development of updating plans is an important part of implementing future business plans. Updating is defined as technical and professional development subsequent to first qualification as a professional practitioner. It can cover a wide range of topics dealt with in many ways, ranging from counselling on the job to a specialized short course or the use of distance learning systems. Information technology (IT) is an important example affecting most of industry. Updating courses usually have a short-term objective and are aimed at solving specific problems—they differ in nature from most initial courses. Finally the questions of certifying and quantifying units of continuing education and training are also considered.
A Study of Pressure Fluctuations in the Suction Lines of Positive Displacement Pumps
Authors: Edge K A , de Freitas F J T 
Published: February 2007

This paper is a contribution to the understanding of the generation and transmission of pressure ripples in hydraulic systems. Previous research on fluid-borne pressure fluctuations in hydraulic systems has been largely directed towards high pressure lines. This paper examines the behaviour of the pressure fluctuations in axial piston and gear pump suction lines. It has been found that the unsteady flow taken in by a pump creates a standing wave in the inlet line in much the same way as a delivery line. The magnitudes of the pressure fluctuations are very sensitive to mean inlet pressure, due to changes in inlet flow ripple with mean pressure. No evidence of air release in the inlet line was found and it is concluded that at low inlet pressures air release occurs in the pump inlet passageway, although in microscopic proportions since no reduction in volumetric efficiency was observed. System air-borne noise was found to be very dependent on mean inlet pressure.
Conditions under Which Wind Turbines Can Be Financially Viable for Private Power Generation in Industry
Authors: Thabit S S , Primrose P L 
Published: February 2007

Methods of evaluating the economics of wind energy conversion systems (WECS) reported in the literature are not readily understood by management in industry, and are not presented in a form suitable for appraising industrial investment in capital projects. This has led to companies being unaware of the advantages of investing in WECS as an option in private electricity generation. This paper presents the general principles of a comprehensively structured method of investment in a wind turbine, using a company's own local and financial conditions. The return on such an investment for an example company in south-east England is 15.8 per cent, rising to 22.4 per cent if the same company was located in North Wales where wind availability is slightly higher. These results indicate that the prospects of economically viable WECS installations for industrial applications are evident over large geographical areas of the UK.
Design Equations for Preventing Buckling in Fabricated Torispherical Shells Subjected to Internal Pressure
Authors: Galletly G D 
Published: February 2007

Design rules to prevent buckling in thin fabricated torispherical shells subjected to internal pressure are not yet available in either the American or the British pressure vessel Codes. They are the subject of the present paper and some possible design equations are suggested. The equations were obtained from the buckling equations for perfect torispheres after considering all known experimental results on fabricated models. The empirical constants in the proposed design equations depend on the type of head construction used, i.e. whether crown and segment or pressed and spun. For both types of head the equations give a factor of safety of at least 1.5. The design equation proposed for the crown and segment heads was also checked on several large vessels which had failed in service. The safety factors found for these cases were all greater than 1.7, which means that the vessels would not have buckled if the design equation had been available at the time. The other failure mode of these torispherical heads, i.e. large axisymmetric deformations leading to through-thickness yielding, is also discussed briefly. Curves are given which show that, for 300 < D/t < 500, buckling controls the failure mode in some cases and axisymmetric yielding in others. Neither the American nor the British codes recognize that buckling can occur in this D/t range but the theoretical predictions have been confirmed by experiments. However, the amount of test data is limited and more work is needed on the topic. It is also shown in the paper that, for torispherical shells with D/t ratios in the range 300 < D/t < 500, the axisymmetric limit pressures, pDS, are lower than both the internal buckling pressures and the large deflection axisymmetric yielding pressures. From this, one would expect the failure modes to be axisymmetric in this D/t range. However, as some non-symmetric buckling failures have occurred, the limit analysis predictions for the failure mode are thus not always correct. One feature of the experimental results on stainless steel torispherical shells which are reviewed in the paper is the relatively poor buckling performance of the heads tested by Kemper in comparison with similar heads tested by Stanley and Campbell. As the values of the empirical constants in the design equations are controlled by the lowest test results, the higher bucking pressures obtained by Stanley/Campbell cannot be utilized unless an adequate explanation for the difference in the two sets of results is forthcoming.
A Method for Reducing the Corner Wear in Plunge Grinding
Authors: Radhakrishnan V , Achyutha B T 
Published: February 2007

There are many cylindrical grinding operations like crankshaft grinding in which the corner radius is critical and hence, the corner wear is important. Studies with a patented side-grooved wheel have shown a remarkable improvement in the performance of the wheel. With the side-grooved wheel, there was reasonable reduction in grinding forces, wheel corner wear and glazing tendencies. This paper deals with a detailed investigation on the performance of side-grooved wheels in cylindrical plunge grinding applications.