bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cup-drawing from a Flat Blank: Part I. Experimental Investigation
Authors: Chung S. Y. , Swift H. W. 
Published: October 2007

Part I gives an account of an experimental investigation of the forces, work and strains involved, and the conditions for successful drawing of a cylindrical shell from a flat circular blank. It is claimed that the results are sufficiently accurate to provide a basis of reference for theoretical treatments of cup-drawing, as well as an empirical basis of comparison between different drawing conditions. The work was carried out in an experimental crank-press of 50 tons nominal capacity, and was based on a cup diameter of 4 inches. Blank thicknesses from 0·025 to 0·060 inch were used, and although most of the work was carried out on a low-carbon rimming steel, comparative tests were made with aluminium, brass, and copper, of different tempers. The conditions examined included methods of blank-holding, drawing ratio, punch and die profile radii, punch-die clearance, and blank thickness. Although this part has no theoretical pretensions, it includes a descriptive account of stresses and strains in the deep-drawing process, based on plastic theory.
The Marine Gas-turbine from the Viewpoint of an Aeronautical Engineer
Authors: Fletcher A. Holmes 
Published: October 2007

In view of the intensive development of gas turbines for aeronautical purposes, the author advocates the adoption of aero-design techniques for the production of gas turbines for marine and stationary purposes. A review is made of the more obvious features of various typical aircraft turbines, and the conclusions are drawn that multiple combustion systems and single- or two-stage turbines should be employed with a considerable reduction in the mass of metal in the assembly as compared with extant stationary designs, in order to reduce transient temperature stressing. A description is given of an experimental heat exchanger embodying the principles of light scantlings, symmetry of design, and purity of suspension. A brief excursion into the performance calculations for a marine turbine leads to a recommendation to use a compound cycle of 8/1 overall compression ratio, with centrifugal compressors for robustness, and with a high combustion-temperature involving the use of air-cooled blading. A life of 10,000 hours appears to be within reach, which figure is considered to be adequate for merchant ship service. A compact arrangement is suggested for a turbine of this type giving 4,000 s.h.p. at an overall thermal efficiency of 30 per cent. The manoeuvring and reversing problems are to be overcome by the fitting of a variable-pitch propeller, but development work on this device is required to reduce its alleged tendency to greater losses as compared with the fixed-pitch type.
Mechanical Engineering around Bristol
Authors: Cooper A. B. 
Published: October 2007

A general outline of the mechanical engineering activities of Bristol and the surrounding areas is used to illustrate the achievements resulting from local enterprise and development. Details of industrial techniques are not described. The production of aircraft engines of world renown and the work of paper conversion, for which Bristol is one of the most important centres in Britain, are given major emphasis and reference is made to the manufacture of mechanical handling equipment, and brewing and paint-making machinery.
Explosions in Enclosed Crankcases of Reciprocating Engines: Their Cause, Effect, and Possible Remedy
Authors: Lamb John 
Published: October 2007

In this paper is treated the important problem of crankcase explosion prevention in practice. After dealing with the cause of such explosions the author concludes that, whilst much can be done to minimize explosions, to prevent them altogether is not practicable. The merits of ventilation of crankcases are discussed and ways are suggested to prevent bearings running hot, while means to detect a temperature rise in inaccessible bearings and pistons are described. Tests carried out with the object of preventing injury to personnel and damage to property in the event of an explosion are described. A relief valve which opens and closes instantly is described and illustrated. The danger of burning gases issuing from relief valves is discussed, and the experiments are described which resulted in the evolution of a simple but effective flame trap. Relevant particulars are given of a Diesel engine in which two crankcase explosions took place, one before and one after a relief valve was fitted. The gas pressure in the crankcase when damage resulted is estimated and views are expressed regarding the relation of crankcase cubic contents to the area of relief devices.
The Recovery of Diamonds by Modern Mechanical Methods
Authors: Bone J. 
Published: October 2007

The exceptional hardness of the diamond and its resistance to abrasion are becoming more widely appreciated throughout the industrial world and resulting in its increasing use in the manufacture of drills, drill crowns, crowning wheels, hardness indenters, lathe tools, nozzles, saws, wheel dressers, wire-drawing dies, and many other products. The industrial diamond as distinct from the gem diamond is, broadly speaking, one that—on account of imperfections such as inclusions, spots, cracks, cuts, inferior crystal form, or dark colour—cannot be economically cut and utilized as a gem stone. The unit of weight for industrial diamonds, like that for the gem stone, is the metric carat; which is equivalent to 0.2 gramme. Approximately tons of diamonds a year, an amount corresponding to about 80 per cent by weight of the world's present annual output, is used in industry. The increasing demand for industrial diamonds was responsible for the reopening of the mine in the Transvaal in which the modern mechanical plant described in this paper was installed.
The Flexural Vibrations of Thin Cylinders
Authors: Arnold R. N. , Warburton G. B. 
Published: October 2007

The flexural vibrations of the walls of thin cylinders are considered. In this type of vibration many forms of nodal pattern may exist owing to the combination of circumferential and axial nodes. Theoretical expressions are developed for the natural frequencies of cylinders with freely-supported and fixed ends and a comparison is made with the frequencies obtained experimentally. In practice, the ends of cylinders are subjected to a certain degree of fixing by end-plates, flanges, etc., and the natural frequencies thus lie between the corresponding values for freely-supported and fixed ends. To make possible the estimation of such frequencies, a method is devised in which an equivalent wavelength factor is used. This factor represents the wavelength of the freely-supported cylinder that would have the same frequency as the cylinder under consideration when vibrating in the same mode. The results of experimental investigations with various end thicknesses and flange dimensions are recorded, and from these the equivalent factors are derived. Sets of curves calculated for cylinders with freely-supported ends and covering a range of cylinder thicknesses are given. From these it is possible to obtain close approximation to the frequencies of cylinders under other end conditions by the use of an appropriate factor. An example is given of frequency calculations for a large air-receiver for which two frequencies were identified by experiment.
How American Industry is Attacking the Problem of Materials Handling
Authors: Bright James R. 
Published: October 2007

Materials handling is one of the fundamental activities of mankind, and the common denominator of all industry, yet it has been relatively neglected by engineers and managers generally. In the United States realization is growing that materials handling accounts for the largest single activity cost in much of manufacturing and distribution. Although many individuals are fully conscious of this, companies differ widely in this recognition and in the way they are trying to improve their materials handling activities. The aims of this lecture are to clarify the major objectives of a materials handling programme; to show how progressive companies are organizing for materials handling; to describe the scope of the good materials handling programme; the type of individuals to be placed in charge; the authority and responsibilities to be delegated to them, and the ways in which these activities co-ordinate with, and contribute to, other aspects of the plant. Techniques of analysing materials handling problems and the characteristics of basic materials handling devices are presented briefly. Some fifteen significant trends in American materials handling practice will be discussed and briefly illustrated by case examples.
Mechanical Engineering Features of Nantgarw Colliery
Authors: Dash T. G. , Pettit J. 
Published: October 2007

Nantgarw colliery is the subject of a major reconstruction scheme, the details of which are of interest to mechanical engineers. Many of the major features including the shafts, winding engines, air compressors, mine-car handling equipment, and stowage material preparation plant are outlined in this paper. Because of the necessity to wind from more than one level in the pit, the shafts have equipment which is a departure from the conventional types in use in Britain. The method of mining to be used is known as the “Horizon” system, well favoured on the Continent for steeply inclined seams. The chief feature of the system is that horizontal roadways are driven to the seams at convenient vertical distances apart. The use of compressed-air power is mentioned, together with reasons for the choice of the air- compressors installed. The system of transporting coal and materials within the colliery is dealt with at some length, because of its originality and its improvement over the systems in being at the older collieries. A fairly full description has been given of the shale preparation plant for stowage material for underground use. This is the first plant of such a size to be designed in Britain, and it has been developed from experience gained in smaller units built at nearby collieries.
Developments in Steel Castings in the Heavy Power Plant Industry
Authors: Buckley F. 
Published: October 2007

Though the application of steel castings in the field of the prime mover is selected as a basis for treatment, the opportunity is first taken of mentioning developments inside the foundry that appertain to manufacture and inspection. The trend towards more stringent service conditions has augmented the responsibility of the foundry for the production of castings free from defects. There are indications that the designer and user of castings can with advantage pursue and develop the tendency to break down designs into relatively simple constructions that can be fabricated together at a later stage, and examples of this type of construction are given. Where this trend is impracticable, a strong case can be made for the concentration of allied types of work in relatively few foundries. Mention is made of the trend of research as applied to steel castings, and the lasting importance of methods departments is stressed.
The Athlone Fellowship Scheme for the Practical Training in Industry of Canadian Engineering Graduates in Great Britain
Authors: Abbott W. 
Published: October 2007

This scheme, now in its third year of operation, is designed to bring to Great Britain every year thirty-eight Canadian graduates in engineering for post-graduate studies. The Fellowships have a duration of two years and are tenable in industry, in universities, or partly in each of these. The author has been connected with the scheme from its inception; he assists in the selection of the graduates in Canada and arranges for their location and training in the United Kingdom. The paper describes in some detail the origin, purpose, and operation of the scheme and raises many issues of interest and importance. The author also gives summaries of the reactions of Athlone Fellows who are now receiving postgraduate training in Great Britain. The purpose of the paper is twofold: to give information concerning a new and important system of Fellowships, and to evoke constructive criticism from professional engineers of its objects and operation.
Formulation of “Stability Equations” and Derivation of New Constructions with Complete Systems of Design-formulae for Variable-speed Control Mechanisms
Authors: Frenkel M. S. 
Published: October 2007

Requirements for stability are formulated mathematically and, through the “transformatory operations of mathematics”, yield a series of “stability equations” of ascending order which are generally applicable, for example to control mechanisms, electronics†, nuclear physics, etc. From these stability equations, the equation of the stable characteristic curve of a governor, and the differential equations of the oscillations of a governor-engine system, are derived. It emerges that the first part of the new oscillatory equation is identical with the whole of the differential equation in the literature to date (unchanged since Maxwell 1868)‡, while the important second part, which consists of terms of the same order of magnitude as the first part and which is the only one containing the equation of the stable characteristic curve, is lacking in literature. The stability equations classify all possible constructions of variable-speed governor according to “order of stability”, which signifies important operating properties. This classification accounts for the known shortcomings of conventional types. The stability equations, combined with the mathematical formulation of practical requirements (speed-adjustment with only one actuating motion, etc.), lead to new basic types of variable-speed governor, with complete systems of design equations. In addition to determining all unknown dimensions, this set of equations is important because it derives constructions of which the complexity increases with order of stability and, furthermore, a simple construction which provides any required high order of stability with the minimum number of adjustable components.
An Experimental Single-stage Air-cooled Turbine: Part I. Design of the Turbine and Manufacture of Some Experimental Internally Cooled Nozzles and Blades
Authors: Reeman J. , Buswell R. W. A. 
Published: October 2007

To facilitate future development of the cooled gas-turbine more test information is needed on the effectiveness of cooling in an actual turbine operating at high gas-temperatures. Part I of this paper deals with some design aspects of a single-stage experimental turbine built to enable an experimental investigation to be carried out on the air cooling of nozzles and blades. The turbine, built for operation at high gas-temperatures, was fitted with internally air-cooled blades having a large number of small cooling passages running the whole length of the blades. A description is given of the pressed powder technique used to introduce the small passages in blocks of heat resisting material from which the blades could be machined. Mention is made of some of the difficulties encountered in this method of manufacture and also of the need for careful consideration of suitable methods of disposal of the cooling air when internally cooled nozzles and blades of this form are used.
A Note on the Theory of Rolling with Tensions
Authors: Bland D. R. , Sims R. B. 
Published: October 2007

In this note is suggested a modification to overcome the difficulty met in the application of Bland and Ford's simplified theory of strip rolling to passes where heavy back tensions are applied. An equation for the roll force is evolved and compared with those of Orowan and of Bland and Ford. Experimental and calculated values of roll force given show an accuracy to within 10 per cent.
An Investigation of Small Helical Torsion Springs
Authors: Berry W. R. 
Published: October 2007

The object of the investigation was to provide easily handled data for the design of helical torsion springs from round patented plain carbon spring-steel wire. For this purpose, the validity of the curvature correction to the stress formula was investigated and the effects of variations in low-temperature heat treatment and wire size were explored. It was found that the theoretically derived curvature correction for maximum stress (stress at intrados) was the dominating feature in fully heat-treated springs under all conditions, and for patented wire springs when the maximum stress was tensile. In patented wire springs, however, when the maximum stress was compressive it was found that, although with springs of small index the maximum stress was still the dominant feature, with those of large index yielding was due, not to the maximum compressive stress at the intrados, but to the smaller tensile stress at the extrados, and that a critical ratio existed where yielding occurred simultaneously at both extrados and intrados; a finding that has considerable practical value. It is suggested provisionally that the phenomenon may be due to the combined effect of the low-temperature heat treatment, which relieves textural stresses (present in the wire as the result of the drawing operation and the presence of cementite) and at the same time allows the strain-age-hardening effect to become evident. Design charts are submitted incorporating the results of the above investigation.
The Transmission of Low-pressure Steam for Process Heating
Authors: Geneve L. F. C. A. 
Published: October 2007

In this paper is shown how in the case of steam transmitted entirely for use in process heaters, it is the total heat energy that finally counts; and hence a pipe-line can be designed for a high pressure drop and a high velocity of flow, since the friction work and the kinetic energy will be reconverted into heat which is also available at the outlet of the pipe-line. The size and cost of the piping and lagging can therefore be kept low, and radiation losses will also be reduced. In a long transmission, however, the very rapid increase of velocity towards the end of the pipe-line may cause the steam velocity to reach the “acoustic” value; and when this occurs a “choking” effect results in the discharge being lower than the expected value. The method of design proposed is to calculate the size of pipe required so that the given length of pipe-line is an assumed fraction, say, 0.80 to 0.90 of this “choking” length. This ensures that the required discharge will be obtained with the minimum size of pipe, and with no danger of “choking”. Simple formulae are derived with the help of the approximate Callendar expression for total heat, which is applicable with reasonable accuracy at low pressures; and a case is worked out for a combined power and process steam installation, which shows that the problem may have several solutions of equal heat utilization efficiency.
Practical Training in Industry for the Graduate in Mechanical Engineering: Part I
Authors: Evans Kenneth R. 
Published: October 2007

Part I of this paper reviews the changing outlook during the past forty years on methods of training the mechanical engineers of the future. Industry and universities have reviewed and amended traditional methods and outlook in significant ways and, in particular, in ‘bridging the gap’ between those responsible for training in industry and those responsible for policy and curricula in the universities. The effects of two world wars and the incidence of military service are indicated. Financial considerations concerning fees and maintenance during both university training and apprenticeship are related to opportunity. The influence of the present conditions of more jobs than there are suitable applicants is considered in relation to long-term planning of the training of the mechanical engineer of the future. The general lines of procedure usually required for those who include a full-time university course as a part of their education and training are considered, and particular attention is given to the increasingly accepted view that pre-university practical training has many advantages which are now recognized by professors and others who teach in the universities and senior technical colleges. The need for work and play which educate and relax the young man during his post-school five-year formal engineering training period is explained and examples are given; and reference is made to the fact that those least interested in ‘outside’ activities usually benefit most if encouraged and helped to participate in such activities. It is pointed out that the common good of the individual, the university, the firm, and the nation is most likely to be achieved if a long-term view is always given preference, and that, while time is all important and must not be wasted, time must be given to the preparation for a future career—preparation ample enough to fulfil the demands that opportunities and responsibilities in later life will make.
Corrosion Studies on a Model Rotary Air-preheater
Authors: Thurlow G. G. 
Published: October 2007

Tests have been carried out on a model rotary air heater in an attempt to study, on a laboratory scale, corrosion phenomena under conditions similar to those experienced in industrial practice. The acid dew-point of the combustion gases used varied from 240 to 320 deg. F. and maximum corrosion occurred at surface temperatures within the range 215–240 deg. F. The results confirm previous conclusions as to the influence of the acid dew-point and of the sulphur trioxide content of the gases on corrosion.
The Theory of Plasticity: A Survey of Recent Achievements
Authors: Prager William 
Published: October 2007

After a brief historical introduction, recent achievements in the theory of plasticity are surveyed with emphasis on applications in mechanical engineering. Kinematic models are presented that indicate the complexities of mechanical behaviour in the plastic range. The fundamental theorems of limit analysis are discussed, and their application to two- and three-dimensional problems is illustrated by examples. Shakedown analysis and limit design are defined. Problems involving large plastic deformations are discussed with special reference to metal forming processes. Applications of the theory of plasticity to impact testing and blast damage are reviewed. Recent changes in the theory of structural stability in the plastic range are mentioned. Throughout the lecture, impending developments of the theory of plasticity are indicated.