bluuebunny/crossref_metadata_2025_split huggingface dataset:
Production Research in Its Application to the Machine Shop of a Dockyard
Authors: Schlesinger G. 
Published: October 2007

The author was entrusted with the task of reorganizing the machine shops of the Wilton-Fijenoord shipyard at Rotterdam-Schiedam in 1936 and of raising their output considerably. It was uneconomic to replace all the old machines; machines which were not adaptable were gradually eliminated, whilst those capable of having their speed doubled and of working to precision limits were rebuilt. All hand-grinding machines were removed from the shop and collected in a central grinding department, and the number of materials was reduced from 50 to 14 machining groups. For each group the tool angle, size and shape of tip and shank, and the tool steel to be used were fixed so that the optimum output coincides with the minimum cost of materials and repairs. To ensure that the instructions given by the rate fixer are followed by the workmen, an engineer continuously inspects the work produced. A form was drawn up, and is reproduced, giving all the data required by the operator for carrying out the rate fixer's instructions.
The Yield of Mild Steel with Particular Reference to the Effect of Size of Specimen
Authors: Morrison J. L. M. 
Published: October 2007

The paper is a description of an investigation undertaken to determine, by tests under various conditions of uniform and non-uniform stress distribution, the criterion of yield in specimens of mild steel. Apparatus is described for heat-treating the material after machining in such a manner as to avoid surface decarburization, and for determining the stresses at yield of specimens tested in tension, compression, flexure, torsion, and combined tension and torsion. The results show that the material used is uniform and isotropic. No differences are found between the yield in tension and compression. Tension tests on thin tubes and on solid specimens of varying size indicate a progressive change from single-crystal stress-strain characteristics to the normal characteristics of polycrystalline material. Tests in combined tension and torsion give results which accord with the theory of yield at a critical value of the shear strain energy stored per unit volume of the material, but this is shown to be entirely due to the size of the specimens tested. In all cases of nonuniform stress distribution, the yielding is shown to depend on the specimen size, being delayed until a shear stress not less than the shear stress at yield under uniform stress is applied to a thickness of material of the order of a few crystal diameters.
The Lubrication of Steam-Turbine Driven Electric Generators
Authors: Cowlin F. J. 
Published: October 2007

The paper briefly reviews the problems arising in, and the system employed on, the lubrication of large modern steam-turbine electric generators. A description is given of the general layout, enumerating the various components and the reasons for their inclusion. The general qualitative relations governing the operation of film-lubricated bearings are briefly stated; published results of full-scale experiments on commercial types are compared; and a simple method is given for estimating the power absorbed, based on practical experience. Various types of oil pumps, and the principles adopted in fixing their capacity are described, the results on gear type pumps being shown by several curves. The development of modern forms of oil-cooling apparatus is traced, attention being given to factors affecting the rate of heat transmission obtainable; a series of tests carried out on a modern type are described. Curves showing the relation between heat transmission rates and oil and water velocities obtained from these tests are reproduced. The disposition, design, and capacity of oil tanks are discussed, together with the practical aspects of piping layouts. The concluding section deals with the properties of lubricants, factors contributing to deterioration, and methods of purification commonly employed.
Recent Developments in the Use of Hydraulic Power
Authors: Town H. C. 
Published: October 2007

Hydraulic power development may be divided into two groups, first, one in which mechanical and civil engineering developments combine to use natural forces for power production, and second, the phase of hydraulic power development which it is proposed to consider, namely that appertaining to mechanical production and automotive traction. Until recent times, no phase of engineering development has remained comparatively stationary for so long a period as that of power operation by hydraulic means. It is true that there has always been a field where the characteristics of hydraulic power were essential, but in the more recent drawing and stamping industries, hydraulic operation was unable to compete until developments in collateral fields removed all disadvantages. Prominent amongst the developments to this end, has been the introduction of the variable-delivery pump to each machine, as against the central pumping station. These self-contained units are available with a normal maximum pressure of 1,000 lb. per sq. in., but in certain cases no less than 5,000 lb. per sq. in. can be obtained.
The Creep Recovery of a 0.17 per cent Carbon Steel
Authors: Johnson A. E. 
Published: October 2007

Since 1876 occasional interest has been shown by investigators in the phenomenon of creep recovery, or what has been sometimes referred to as delayed elasticity or subpermanent elasticity. This may be defined as the negative strain, increasing with time, which occurs when a specimen strained under load, as in a creep test, is unloaded and maintained at its working temperature. Theories have been advanced to account for the phenomenon, but sufficiently full data have not been obtained for any of the commonly used commercial materials to provide means of checking the theories. The present paper, for the case of a 0·17 per cent carbon steel, investigates the relation between recovery and the stress, temperature, period of test, and strain, in the creep test preceding the recovery, and presents data by means of which the existing theories are compared. Creep and recovery tests were made in creep units capable of measuring creep rates of the order 10–8 in. per in. per hour, the test temperature being maintained constant to ±0·5 deg. C. At each of the temperatures 425, 455, and 485 deg. C., groups of creep tests—continued to periods of 0·2, 2, 20, and 145 hours, respectively—were made, each group consisting of tests at three different stresses. Each test piece on unloading was allowed to recover for 100 hours. One or two similar tests were also made at 350 and 550 deg. C. In addition, at 425, 455, and 485 deg. C., groups of creep tests were made, and were carried to the stage of minimum creep rate; the test piece was then unloaded, and allowed to complete its recovery. These groups of tests also consisted of tests at two or three stresses. The author discusses the relation of creep recovery to stress, temperature, period of creep, and strain in the initial creep test, and finally tabulates his principal conclusions which, he points out, apply only to the steel tested, and are not to be taken as generally true for other materials. A bibliography is also included in an Appendix.
A New Mathematical Method for the Solution of Film Lubrication Problems
Authors: Christopherson Derman G. 
Published: October 2007

The paper applies the technique of the “relaxation” method to the problem of fluid-film lubrication. It is found that a solution to Osborne Reynolds's governing equation can be obtained by this means in all cases of practical importance. The method also renders possible a new treatment of the difficulty presented by the occurrence of divergent films in journal bearings. The problem is shown to be tractable even when viscosity is correctly treated as a function of both temperature and pressure; moreover, as a part of this treatment, means of estimating the temperature distribution over the bearing surface are provided. A numerical example is used to illustrate the modifications in the solution resulting from viscosity variation.
Balancing of Locomotive Reciprocating Parts
Authors: Cox E. S. 
Published: October 2007

Since the British Bridge Stress Committee's report† of 1928, an increase has occurred in the speed capacity of locomotives. After showing how the recommendations of that Committee have been met in modern British locomotive design, the effects of higher rotational speeds are discussed, and tests with the lifting of coupled wheels off the track at maximum speeds and with various proportions of reciprocating balance are described. Since the necessity may arise for reducing hammer blow values still further to meet civil engineers' requirements, the possibility of reducing or eliminating the amount of reciprocating balance becomes important. The effect of this factor on the locomotive itself is discussed theoretically, expressions being given for the amplitude of the resulting horizontal and lateral oscillations. Available practical evidence in support of the theoretical considerations is described, and conclusions are reached regarding the conditions under which it is still necessary for locomotive reciprocating parts to be balanced.
The Axial Vibration of Diesel Engine Crankshafts
Authors: Poole Ralph 
Published: October 2007

The paper describes an investigation carried out to determine the magnitude of axial vibration of engine crankshafts, with the object of establishing that axial resonance may occur within the normal running range of an engine. The author gives the results of tests on various makes of engine using a portable vibrograph to record the axial movement of the crankshaft. In some cases the torsional osculation was measured simultaneously by means of a universal vibrograph. The vibrograph records show that at certain speeds some engines are subject to a very marked increase in axial vibration of a magnitude consistent with a condition of axial resonance. The author describes a test in which the natural frequency of axial vibration of a crankshaft is determined experimentally by using an a.c. electromagnet as a means of applying an alternating force. Expressions are derived for calculating the axial deflexion of a crankshaft due to the piston load, and also for calculating the axial deflexion under an axial load. It is suggested that the relation between these two deflexions determines the magnitude of the axial force set up by the piston loading. From a series of load-deflexion tests, carried out on a number of crankshafts, the author determines the value of empirical factors to be used in estimating the axial stiffness.
Distribution of Boiler Load
Authors: Kaufmann Paul G. 
Published: October 2007

The paper deals with the load distribution between a number of boilers operating in parallel, with a view to obtaining minimum fuel consumption. The application of the theory of minima leads to a graphical solution, and it is demonstrated that maximum plant efficiency can generally be obtained only when all boilers share in the load fluctuations to an extent depending on the input-output characteristics of the various boilers and on the momentary load. The division of a plant into groups of boilers operating at base load and fluctuating load, respectively, is generally not economical. Automatic boiler control not only increases the operating efficiency of the individual boiler but can be used also for maintaining the most economical load distribution between the units, and thereby also raises the efficiency of the plant as a whole. The paper also discusses how many and which units should be used to cover a given load range, and when a boiler ought to be banked or connected to the line again. This depends upon the ratio between standby and operating periods; but generally it will be more economical to operate all boilers down to their minimum load than to bank some of them. The same principles of load distribution can be applied to the parallel operation of any kind of machines other than boilers.
The Linen Flax Industry and its Introduction to New Zealand
Authors: Barltrop S. B. 
Published: October 2007

Although the possibilities of linen flax cultivation in New Zealand were first explored in 1936, it was the German invasion of France and the Low Countries—the flax-producing areas of Western Europe—which caused the British Government in June 1940 to make an urgent request for New Zealand to grow up to 15,000 acres of flax and to arrange for its processing. At that time there was not, in the whole of New Zealand, more seed than would suffice for sowing 2,000 acres; and some 500 tons of seed had to be imported from Great Britain. The paper describes how the difficulties of starting a new industry at such short notice were successfully overcome. The New Zealand Government secured the co-operation of the farmers in preparing the ground, and of the railway workshops in constructing the machinery. Essential materials were in exceedingly short supply, and the author recounts the way in which those responsible for the engineering side of the industry grappled with, and overcame, the difficulties which confronted them, and shows with what measure of success their efforts in conducting the new venture were rewarded. The paper gives an account of the various processes in the production of linen flax for export, with descriptions of the machinery used, and concludes with a brief outline of the New Zealand Government's programme for 1941–2. Further statistical data relating to the industry are included in Appendixes I–IV, pp. 168–9.
The Measurement of Torsional Vibrations
Authors: Stansfield R. 
Published: October 2007

An electromagnetic torsional vibration pick-up unit, developed at Sunbury in the Research Laboratories of the Anglo-Iranian Oil Company is described, the output being shown on the screen of a cathode ray oscillograph to which the unit is connected through an integrating amplifier. Calibration curves are given to show the limits of accurate response, and methods for calibrating in service by simple checks are outlined. Torsiograms taken from a two-stroke and a four-stroke Diesel engine illustrate the type of diagram obtained for each cycle of operations. The value of the unit is much increased by including an electrical filter system in the output. The resulting diagrams show any required harmonic component of the swings, and enable a sufficiently accurate analysis to be made on the test bed either of critical speed swings, forced swings on flanks, or major roll amplitudes. The technique for taking diagrams with this filter unit is described in detail. Examples from actual test records are discussed in relation to points of particular interest in connexion with friction dampers, rubber absorber dampers, systems with two modes of vibration, etc.; and finally a brief reference is made to the measurement of linear vibrations.
Corrosion of Boiler Tubes
Authors: Turner T. Henry 
Published: October 2007

The reduction of the number of boiler tube failures to a minimum is now a matter of national importance. Revolutionary improvement is not expected in the nature of the tubes. Tubes fail rapidly by local, and less rapidly by general, corrosion. The removal of scale by shot blasting before use will reduce the extent of losses due to pitting, and so will additions of 0·2–0·5 per cent of copper. Metallurgical data regarding tubes, and chemical data regarding feed waters are summarized in the paper, from the author's extensive records. After discussing how corrosion occurs at cracks in oxide, scale, or paint, suggestions are made for preventing corrosion in locomotive, marine, and stationary boilers. Recommendations include simplification and standardization of boiler water tests by a suitable British Standards Committee, and the suggested Specification is sketched in outline. The paper is concluded by Appendixes comprising (i) a questionnaire (with answers) on the present-day practice as regards the manufacture of boiler tubes in Great Britain; (ii) a list of reports published by the American Railroad Engineering Association; and (iii) a bibliography of selected items on corrosion, for the index prepared and maintained at the Chemical Research Laboratory, Teddington.
Some Textile Finishing Machines
Authors: Laurie K. S. 
Published: October 2007

Textile finishing comprises the processes undergone by cloth between leaving the loom and being made up for sale. Finishing works require large premises, situated by good water supplies. Dyeing machinery to-day shows a greatly extended use of stainless steel construction. The problem of dye-jigger driving at constant speed is discussed by the author. Moisture removal is an outstanding problem. Mechanical methods and heat methods are compared; and the machinery appropriate to each is described. In modern drying machines provision is made for tensionless drying, for working to controlled cloth dimensions, and for the handling of very delicate fabrics. Methods of feeding cloth automatically by roller or by rail guiders are discussed, and attention is given to the recent development of pneumatic and hydraulic systems. The use of calenders for finishing is long-established and has modern developments, which are described in the paper.
Surface Finish and the Function of Parts
Authors: Schlesinger Georg 
Published: October 2007

The author begins by enunciating the principle that, given good design, a machine will work properly when the material, the fits and tolerances, and the quality of the surfaces are chosen to suit the working conditions, and then gives examples to show the improvement effected by proper attention to suitable fits, tolerances and working surfaces. The use of pen records to provide data for surface finish is dealt with, and an account is given of comparative tests of British and German aero-engine parts. Fits for various functions are discussed and attention is paid to problems relating to lathe spindles, and the surfaces of fuel injectors. Ground and scraped surfaces are compared, and further sections are devoted to micro-finish by honing, the superfinishing process, and the dulling criterion for finishing tools.
Power District Heating at Brno, Czechoslovakia
Authors: Kulka W. 
Published: October 2007

The most effective way to large-scale saving in industrial fuel is the pooling of power and steam consumption. This method, if spread over a wide area, say an industrial town or district, inevitably paves the way to district heating. Ordinary district heating stations, distributing only low-pressure saturated steam or hot water from one central boiler house to consumers in the vicinity, are of but secondary importance when the aim is high overall thermal efficiency in the distribution and consumption of power and heat. Satisfactory economy can only be achieved by installing high-pressure stations and using the pressure drop down to the pipe line pressure for the generation and supply of electric power. Not every community or district is, however, entirely suitable for the establishment of a power-heating plant. The difficulties arise from the geographical position of the industrial areas compared with the location of the mainly residential districts, from the customary times of use of heat and power, and, last but not least, from long-standing habits or traditions in the production and utilization of heat. The power district heating plant built during 1928–30 at Brno, capital of Moravia, Czechoslovakia, is described as an example where considerable difficulties were overcome. Due to its absolute success, the plant subsequently served as a guide in the planning of far larger stations of this kind. The description in the paper embraces the general layout of the plant, followed by details of the boiler house, back-pressure and condensing turbines, piping inside the station, desuperheater, feed arrangement and make-up plant, heat accumulation, and finally the distribution of steam to the consumers. Further, the report gives some important features of the operation, difficulties arising and how they were mastered.
The Double-Beat Throttle Valve and its Relation to Governing
Authors: Chorlton F. O. L. 
Published: October 2007

The paper contains details of the results of experiments made some time ago on the balancing of a particular form of double-beat throttle valve with the object of elucidating the troubles frequently encountered when using it for the speed control of steam engines. The experiments showed that although apparently in balance, as judged from the design, there was a force tending to close the moving valve of an unexpectedly large amount varying with the size of the valve, the inlet steam pressure, lift from the seating, and the outlet pressure. The paper further gives the application of the results towards improvement in governing; a formula for obtaining an approximate figure of the out-of-balance force from given working conditions, and a design of valve giving almost perfect balance under all working conditions. Curves and tables in explanation are included.
The Impact Tube
Authors: Hodkinson B. 
Published: October 2007

A simple impact tube having a hole facing upstream will give direct and accurate readings of the total pressure or energy of a moving fluid, except in special cases. It is not delicate in setting or design. If the static pressure is known, the kinetic energy or velocity head can be obtained by subtracting the static from the total pressure. If, further, the density is known, then the velocity can be derived. An application is given. The exceptional cases are velocity above acoustic and extremely low velocities. At supersonic velocity there occurs, just in front of the mouth of the tube, a very steep pressure rise, often described as a standing wave or shock plane. The tube now reads less than the total pressure, but this can be calculated by a formula which Rayleigh derived from a study of intense waves. The author, not having seen a direct demonstration separate from wave theory, attempts in the paper to give this, and to sketch what occurs. Test experience confirms Rayleigh's formula. For very low velocities, viscosity has influence; and the tube gives readings which exceed the static pressure by an amount approximately equal to the velocity head × [1 + (3/Reynolds number)].
Causes of High Dewpoint Temperatures in Boiler Flue Gases
Authors: Harlow W. F. 
Published: October 2007

High dewpoint temperature in flue gases in boiler plants causes premature condensation in the cooler gas passages resulting in deposits and corrosion. Evidence is submitted to show that high dewpoint can be caused by the increased temperature of the superheater tubes, the oxide film catalysing the conversion of the sulphur dioxide formed by combustion into sulphur trioxide, thereby increasing the sulphuric acid content of the gases. The trouble is confined chiefly to plants fired by mechanical stokers, pulverized fuel plants generally being unaffected. Coating the catalytic surfaces with lime or fine pulverized fuel ash prevents the action, and it is suggested that these materials sprayed on the tubes at intervals may prevent the formation of acid and its serious consequences.