bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crankshaft Damping
Authors: Draminsky P. 
Published: October 2007

The author attempts to give a correct physical explanation of natural damping by torsional vibrations, and also to obtain approximate formulae for pre-calculation of the damping in any given case. The paper describes experimental work with a single-cylinder engine driven by external power, and excited to torsional vibrations by a spring-loaded cam disk. In this way the damping from the moving parts could be investigated separately, and it was found that the damping was almost entirely due to hysteresis in the crankshaft, and oil damping, due to lateral shaft movements in the main and crankpin bearings, which was directly proportional to the bearing clearance. The paper also gives a simple and practical method for the calculation of damped vibrations in arbitrary elastic systems, and the calculation of hysteresis and bearing damping in a single-cylinder engine. Formulae are given for the total damping in multi-cylinder engines, with or without heavy flywheels, and the results are compared with the measured damping of oil engines in service.
Graticule Ruling in Australia
Authors: Shaw Mansergh 
Published: October 2007

The problems of precision manufacture in Australia, arising chiefly from her geographic isolation, are first discussed. The paper then takes one particular problem from the field of optical manufacture and shows how it was solved for the conditions prevailing in the Dominion. The problem discussed is the production of graticules, or reticles, for range-finders, predictors, gun sights, telescopes, binoculars, microscopes, collimators, and many other such instruments. The first part of the paper deals briefly with methods used in reproducing the pattern, particularly the ruling and etching process. The second, and much the larger, part of the paper deals with the design of the high precision machines which were made for ruling the glass disks preparatory to etching the pattern into the glass. Two such machines were developed, one generating the pattern from the movements of the machine itself, the other, a pantograph, by copying the pattern from master plates. A series of self-checking tests is described by which the accuracy of the generating machine could rapidly be tested to an accuracy of much better than 0·0001 inch. A brief survey of the complete process, from glass blank to finished graticule, is made in the Appendix.
Control of Production
Authors: Lister S. W. 
Published: October 2007

The author sets out to describe the basic principles of production control, and after a brief analysis of the nature of the problem, administrative set-up is described, and reference made to the work of Taylor. The importance of apportioning material before it is issued from the store is emphasized, and the fundamentals of stores accountancy are stated. Accurate and exact planning is the keystone of good production control, and the consecutive processes to which each part must be subjected in the planning department are described. One of the most important of these is the difficult job of estimating standard times of manufacture; records of past performance are useful, but the only really reliable method is time study, the principles of which are very briefly mentioned. No plan of manufacture will work to schedule without a good scheme of incentives for the workers. The guiding principles which have to be kept in mind when preparing a bonus scheme are discussed, and the use of standard minutes applied to individuals and groups is considered. The general lines of procedure on which production control in the works should operate are given in a consecutive form, from the actual booking of an order to the processing of parts through the plant, and the collection afterwards of records of performance. The requirements of production control are then listed under ten headings, and the paper concludes with a few of the more practical points which occur, in firms of various sizes, where parts are being processed to a pre-arranged plan.
The Full Journal Bearing
Authors: Cameron A. , Wood W. L. 
Published: October 2007

The basic mathematics of the full journal bearing have been known since 1904 when Sommerfeld‡ made the complete solution, for the infinite journal, of Reynolds theory of 1886. The detailed application of the theory has not been possible owing to the uncertainty in the choice of boundary conditions. In this paper the Reynolds condition that p = 0 at θ = 0 and p = ∂ p/∂θ = 0 at θ = π + α is shown to follow for the infinite bearing from a consideration of continuity of flow and, equally important, from the shaft stability condition, first put forward by Swift in 1933. It is claimed that this is the final answer to the question of correct boundary conditions. The Reynolds equation for the infinitely wide bearing was solved using these conditions. Assuming the viscosity is constant all round the bearing, the coefficient of friction-load criterion curve has the same slope as experimentally determined curves. The Mathematics Division, N.P.L., computed, by Southwell's relaxation methods (1946), the figures for finite bearings of diameter length ratios of 4, 2, and 1. The theoretical figures for eccentricity ratio-load criterion are satisfactorily compared with some of Nücker's experimental results, and the coefficient of friction, load criterion, figures explain the apparent intercept found by McKee and McKee. A diagram is given allowing the eccentricity ratio c, to be obtained from the load criterion for any bearing of diameter/length ratio from 0 to 4, and this enables the minimum film thickness, which equals (1 — c) x radial clearance, to be calculated.
Producer Gas for Road Transport
Authors: Hurley T. F. , Fitton A. 
Published: October 2007

Immediately before, and during the 1939–45 war a considerable amount of research and development work on the use of producer gas for road transport was carried out by the Fuel Research Station, in close co-operation with several other interested organizations. Road tests showed that none of the existing commercial producers was entirely satisfactory with the fuels most readily available in this country. A new dry-blast cross-draught producer, known later as the Government Emergency Producer, capable of using either anthracite or low-temperature coke, was therefore developed. At the same time the effect of variations in the quality of the fuel was examined and a specification for transport producer fuel was prepared. A survey of potential fuel supplies revealed that the output of fuel complying with the specification, although considerable, was insufficient for general use. Accordingly a modified Emergency Producer—known as the Government Utility Producer—was developed, and this was capable of using coke prepared under special conditions in “high temperature” retorts, thus greatly extending the amount of available fuel. “Activation” of the fuel with sodium carbonate effected a further extension. The serious problem of engine wear was solved by the development of new types of filter to remove dust from the gas. The present position is that, although producer gas is a poor substitute for petrol in a converted petrol-driven vehicle, there is no doubt that transport could be operated on a large scale on producer gas should the necessity arise.
Some Operating Experiences with High-Pressure Steam Power Plant
Authors: Clinch W. N. C. 
Published: October 2007

Between the years 1938 and 1944 the Northmet Power Company placed in commission four high-pressure steam power plant installations comprising 50 and 60 megawatt units at Brimsdown “A” and “B” Power Stations respectively, operating on the 1,900 lb. per sq. in., 930 deg. F. reheat cycle, and two 32 megawatt non-reheating units at Willesden Power Station, operating at 1,300 lb. per sq. in. and 950 deg. F. These cycles were selected for the respective sites from considerations of coal cost and of circulating water make-up facilities, both stations relying upon rail-borne coal supplies and operating with cooling towers. The capacity and design of the plant were largely determined by the available space, existing buildings being utilized to accommodate most of the new machines and auxiliaries. The pressure and temperature conditions involved consideration of creep characteristics in selecting suitable alloy steels for the pressure parts, and their mechanical properties were closely investigated before contracts were placed. Welding was extensively employed in boiler and pipework construction, and preliminary tests and subsequent radiographic examination presented many interesting problems. Early performance figures promised the achievement of the thermal efficiency to be expected from the cycles, and subsequent experience shows that, as indicated by theoretical considerations, the 1,300 lb. per sq. in. cycle is capable of equal or greater economy than the higher pressure with the reheating arrangements. Certain difficulties in operation have been encountered—not all inherently associated with high-pressure working. The paper gives an account of these difficulties and of the steps taken to surmount them. In the light of these operating experiences, the future of high-pressure steam power generation is discussed with comments on features which are considered essential to a successful design of plant. The initial ventures are felt to have been justified by results and by the contribution made to mechanical engineering in general. The present and future urgent need for coal for international barter calls for the fuller development of the use of high-pressure cycles, and experience to date warrants a continued advance toward their more general application.
The Use of Plumber's Resin to Determine the Occurrence of Yield
Authors: Blair J. S. 
Published: October 2007

Brittle lacquers used for the determination of elastic stress have a number of disadvantages, particularly in connexion with the technique of applying them and the need for careful calibration in each case. They are not generally applicable to the whole of very large specimens such as bridges. Plumber's resin provides much the same information more readily and needs only a simple technique. It has, however, the disadvantage that it is necessary to stress the specimen slightly beyond the yield point. The technique of applying it, which is described in detail, consists in little more than the essential point that the resin must be applied hot without the use of a solvent. After the specimen has been stressed beyond the yield point, Lüders' lines are shown by the resin at those points which have yielded. Thus, not only is the ratio of applied load to yield point obtained—and hence the relationship between stress and load in the elastic range, but the most highly stressed parts are immediately indicated on even the most complicated structure, and the Lüders' line pattern gives information as to the type and direction of stress.
A Single-Cycle Test Apparatus for Studying “Loop Scavenging” in a Two-Stroke Engine
Authors: Sammons H. 
Published: October 2007

An apparatus is described for studying the process of scavenging the cylinders of loop-scavenged two-stroke engines. This consists essentially of a full-scale single-cylinder model of the engine with means for driving it for a single porting cycle. Tests upon the apparatus are made at atmospheric temperature and different gases are used at appropriate pressures to simulate the correct densities of the engine air charge and exhaust gas. The choice of suitable gases permits an easy analysis of the trapped charge for the determination of the efficiency of the scavenging process. Some experimental results and conclusions are presented, including the effects of operating with high charge densities and exhaust back pressures. A method is developed of expressing, from the experimental results, the scavenging performance of a given design of ports. This takes the form of curves relating the volumetric total charge supplied and the charging efficiency with the pressure ratio across the ports. These relationships are otherwise independent of the mass charge, the intake density, the exhaust back pressure, and the pressure loss across the cylinder. The influence of crankshaft speed is examined, as also are some causes of lost efficiency.
Research on the Compression-Ignition Engine and its Fuels
Authors: Vaile P. E. B. 
Published: October 2007

This paper, an abstract of the original, is intended to provide information concerning the present status of Diesel fuel research. The paper is divided into two parts, the first of which concerns the types of fuel in use, describing briefly their sources and properties. A short account is also given of the existing fuel situation and how this may influence future research. Part II deals with the effects of fuel characteristics on engine performance, wear, and fouling. The methods of overcoming any deleterious effects caused by the fuel are discussed, and particular reference is made to the beneficial effects of lubricating oil additives. It must be emphasized that most of the work described refers to the high-speed Diesel engine, owing to the unsuitability of large units for laboratory testing. However, this is beneficial since the high-speed Diesel is most sensitive to fuel characteristics, and it serves to disclose the majority of defects that can arise in a Diesel engine.
The Thermal Efficiency of a Hand-Fired Natural-Draught Lancashire Boiler
Authors: Hurley T. F. , Sparkes W. J. 
Published: October 2007

Following the development of the Fuel Research Station “smoke eliminator” fire doors for hand-fired, natural-draught Lancashire boilers, a series of trials was carried out to obtain figures for their performance under a variety of conditions. Most of the trials were made with one or other of two sizes (”singles” and “smalls”) of a Northumberland coal, which was chosen because of its tendency to make heavy smoke; similar results were obtained with both sizes. The figures obtained during these trials, together with those of a few supplementary trials, are used to illustrate the effects of certain variables upon the performance of a boiler of that type. The information presented includes (1) the correlation of smoke intensity with the composition of the flue gases and with thermal efficiency, (2) the use of secondary air and suitable methods of firing to reduce the heat losses caused by incomplete combustion, (3) the effect of too little and of too much excess air upon efficiency, and (4) the effect of load upon efficiency. With the special fire doors, the admission of secondary air over the fire could easily be controlled and a simple method of firing could be employed. In consequence, the efficiency of combustion was maintained at a consistently high level without calling for exceptional skill or effort on the part of the fireman. Maximum efficiency was obtained when the quantity of secondary air was just sufficient to eliminate smoke: decreasing the percentage of excess air by a small amount below the optimum had as bad an effect upon efficiency as a considerable increase. Varying the load also affected efficiency, the maximum being reached well below rated load, but the variation in efficiency between 40 and 100 per cent of full load was comparatively small.
The Influence of Certain Factors on the Performance of a Lancashire Boiler
Authors: Ritchie E. G. , Kirov N. Y. 
Published: October 2007

The paper summarizes results obtained in a programme of research carried out by the British Coal Utilisation Research Association, under the guidance of the Shell-type Boiler and Firing Equipment Committee, an advisory committee convened by the Association in 1943. In this country, 70–80 million tons of coal are consumed per annum in shell boilers of different types or burnt in industrial and heating furnaces in which mechanical firing is, or might be, employed. It is probable that 45–50 million tons per annum are used for steam raising in Lancashire boilers and it is more specifically with this type of boiler that the paper deals. Excess air admitted through or in the neighbourhood of the fuel bed in a boiler represents, perhaps, the most important source of inefficiency, owing to the fact that it results in a substantial increase in gas temperature at the boiler exit. The experiments quoted show that, in terms of fuel consumption per pound of steam produced, increase in exit-gas temperature is responsible for approximately 50 per cent of the total effect of excess air. The elimination of excess air entering the furnace tubes of a Lancashire boiler represents one of the most important possibilities of effecting fuel economy on a large scale. The rate of evaporation in relation to the normal rating of a boiler is another important factor. The investigations described show that, over a wide range of conditions, the heat absorption efficiency of a Lancashire boiler—without an economizer—decreases by 2 per cent for each 1,000 lb. per hr. increase in evaporation. The corresponding figure for the complete plant—boiler and economizer—is 1·8 per cent. It is suggested that the most efficient rate of evaporation with this type of boiler is approximately 70 per cent of normal rating. Under these conditions, with modern equipment and suitable fuel, operating efficiencies up to 80–85 per cent should be practicable. Brief reference is made to “unaccounted” heat loss as an important item in the testing of a boiler and to the influence of boiler and stoker type and the effect of fuel characteristics on efficiency. Many of the points mentioned in the paper are being further investigated in the steam engineering laboratories of the British Coal Utilisation Research Association.
The “Lost Wax” Process of Precision Casting
Authors: Turnbull J. S. 
Published: October 2007

The paper describes a casting process which differs from standard foundry practice in that it uses a wax pattern in a high refractory one-piece mould to produce metal castings with a good surface finish to an accuracy of ±0·002 inch. The process involves making a master pattern in either hard wood or metal, relating it to a soft metal die by precision casting technique, and then the production of wax patterns from the die on an injection machine. Finally, the wax patterns are invested in refractory moulds, the wax is melted out, the mould baked, and the metal component is cast. The “lost wax” process is advantageous in cases where ( a) the metal is unmachinable, or ( b) where the component is of an unmachinable shape, or ( c) where production by other methods takes too long. One of the most common applications is in the manufacture of gas-turbine blades. The tool costs are relatively low compared to the costs involved in alternative methods of manufacture, the die cost being a function of the number of castings required. The production of cheap castings is necessarily dependent on the scrap percentage being kept to a minimum; at present the scrap from the manufacture of gas-turbine blades is less than 30 per cent, and the author surmises that it would not be unreasonable to expect it to be less than 10 per cent in two years' time.
Simplification Creates New Problems for Top-Management
Authors: Merritt H. E. 
Published: October 2007

The reports of the Lemon Committee and of the Anglo-American Council on Productivity draw timely distinctions between the terms “standardization”, “simplification”, and “specialization”. This paper discusses simplification, with special reference to complex proprietary engineering products. The problems examined are those of determining and controlling a range of simplified products; the determination of domestic standards, classified as “manufacturing standards” and “constructional standards” for the components of those products; the need for, and effect of, more refined manufacturing standards with increasing volume of production; the possibility of obtaining varieties of end-product by alternative assemblies of simplified components, through what is here tentatively termed “rationalized construction”; and the increased complexity of the technical problems which the development of those products entails. Finally, attention is directed towards the new problems and responsibilities with which simplification confronts top-management, partly in the closer control of line of products, but chiefly in the integration of the design, production, and marketing functions.
High-Pressure Vessels in the Chemical Industry
Authors: Granville J. J. 
Published: October 2007

The development of high-pressure processes (200–1,500 atm.) in the chemical industry in recent years, often carried out at high temperatures, has helped considerably to cheapen the production of basic materials, such as ammonia and methanol, and has opened up entirely new fields, particularly in the manufacture of important plastic materials, in coal hydrogenation, and in oil-cracking operations, calling for special equipment and novel techniques. This paper deals with the mechanical requirements for high-pressure vessels, and traces progressive changes in their construction during the last thirty years, from cast autoclaves to forged vessels and to modern composite designs, having due regard to the volume-to-weight ratio, construction, inspection, cost, and maintenance. Stress distributions in the cylinder wall, suitable closure mechanisms, the effects of temperature, chemical and physical attacks, and the provisions for stirring, heating, and cooling are discussed. A brief account of the control mechanisms involved and of the necessary vital safety precautions is given.
Mechanical Engineering in the Midlands, 1925–1950
Authors: Everard F. Vincent 
Published: October 2007

Developments of popular interest that have taken place in the mechanical engineering industry in Birmingham and the surrounding districts by the year 1950, which is not only twenty-three years since the Institution last met there but also is the turn of the half century, are briefly surveyed. Power plant, incorporating steam boilers, steam turbines, oil engines, and gas turbines, is discussed, with special reference to the development of the oil engine and its adaptation for special usage in the 1939–45 war. Changes in public and private road transport engines are traced up to the first turbine-engined private motor car. Improvements in the design of machine tools from practical and aesthetic aspects are touched upon. Mass production and its effect on the craftsman, and advances that have been made in factory management, amenities, and the prevention and treatment of accidents are mentioned, as also is the rehabilitation of workmen, with special reference to the work carried on by the Birmingham Accident Hospital. In processes, the hydroblast method of cleaning castings and the automatic rustproofing of car bodies are described.
Education and Training in Engineering Management
Authors: Nelson H. G. 
Published: October 2007

The paper reviews some of the facilities for management training now available, under the headings Education (in reference to courses), Practice (in reference to engineering apprenticeships), and Experience (in reference to interdepartmental experience gained after apprenticeship, and to the exchange of experience in discussion on management problems at professional institutions). The term “management” connotes anything from top-management to junior supervision, and the problems and treatment differ according to the nature of the firm and the level of management considered. Discussion should indicate clearly, therefore, which type of management is under review and, with respect to educational schemes, for what kind of personnel (apprentice, post-graduate apprentice, or post-apprenticeship) the schemes are intended. Some important considerations dealt with individually in the paper include: the provision of facilities for training by individual firms; education in leadership; selection of personnel for management training; the first position of responsibility; and the dangers of over-emphasis on management training.