bluuebunny/crossref_metadata_2025_split huggingface dataset:
Racing Motor Car Design
Authors: Railton R. A. 
Published: October 2007

The development of the racing car to-day is taking place almost entirely in Germany and Italy. It is true that during the last few years British cars have figured prominently in the lists of world speed records, but the cars used for these attempts are not racing cars at all in the true sense of the term. The most important single factor in the suspension of a racing car is to keep the unsprung weight down to an absolute minimum, and this is one of the chief aims of the designer. Independent suspension at all four wheels has been found to have advantages quite out of proportion to the mere saving in weight. There is now a fairly general agreement that if the centre of gravity of a racing car is too low, the tendency to skid is increased. Racing cars built on the front-wheel drive principle have had a considerable success in America, but they suffer from the drawback of instability at the critical speed when rounding a corner. Brakes and transmission have both been developed to a high degree of perfection, but resemble in principle those now used on touring cars. Supercharging is general, largely as a result of special circumstances which the author discusses. The use of heat-resisting alloy steels has also become an important factor in the design of the engines. The author considers also the influence of fuel, tyres, and streamlined shape on the maximum speed attainable on land.
The Mechanics of Flame and Air Jets
Authors: Davis R. F. 
Published: October 2007

Consideration of the conditions existing within the turbulent zone formed by a free disperse jet mixing with fluid at rest surrounding it, leads to the conception of an equation for the mean velocity of the jet in an axial direction. Combining the latter equation with that for the upward drift velocity of the gases in a furnace, an expression is obtained for the trajectory of an overfire, or secondary air jet, projected into the furnace. By a similar process the method is extended to the case of a flame jet, taking into account its acceleration due to buoyancy. The mechanism of combustion is next considered, commencing with an examination of the factors controlling the position of the ignition point in a flame jet, and the derivation of an expression for its location in a powdered-fuel flame. This is followed by the development of a formula for the burning rate of powdered fuel suspended in air, which when combined with that for the mean velocity in a flame jet, enables a relationship to be established between the flame length and the particle size, for the ideal case of a uniform powder. Subsequently, the grading or non-uniform nature of actual powders is taken into account. A method is also described for plotting a flame characteristic, showing the effect of fineness of grinding, turbulence, and burner design on the losses due to unburnt combustible.
Recent Developments in High-Speed Reciprocating Pumps
Authors: Towler F. H. , Towler J. M. 
Published: October 2007

The advent of the self-contained hydraulic press, with its many advantages, has necessitated the development of a compact high-speed pump. For most pressing operations a variable-delivery pump is of little advantage, and such pumps, having rotary valves, are only capable of comparatively low pressures. On the other hand a working pressure of 5,000 lb. per sq. in., with its attendant advantage of compactness, is readily obtainable with pumps having positively seating mushroom type valves. Such a pump is described, which the authors have perfected, and which has a volumetric efficiency of over 97 per cent at 1,500 r.p.m. High volumetric efficiency is essential to obviate noise and vibration at such speeds and to reduce pulsations in the flow to a practically imperceptible amount. To obtain high volumetric efficiency at high speeds the shape and construction of the suction valves are of paramount importance. Some comparative experimental figures are given for the discharge of valves of various shapes. Oil is used as the hydraulic medium as it prevents corrosion and ensures that all working parts are copiously lubricated. The pump is immersed in the hydraulic medium and all rotating parts are mounted on ball or roller bearings. The conditions of loading, the effect of deflexion on the journal bearings, and the special design of shaft are fully described. The paper concludes with various illustrations of self-contained hydraulic presses to which this type of pump has been applied.
Diesel Traction on Railways
Authors: Ambady G. K. 
Published: October 2007

An analysis is made of the various items of locomotive operating costs and the degree to which each is influenced by the type of tractive unit selected, namely, steam or Diesel. The effect of the possibility of a higher “availability” or “serviceability” factor with Diesel locomotives is not likely to be as high as may be supposed. Specification and design details of the various components of a Diesel tractive unit are discussed and in the particular case of a locomotive designed to haul a load of 600 trailing tons at a maximum speed of 60 m.p.h., the main design data and performance curves are worked out with and without supercharging. The author's general conclusion is that Diesel operating costs compared with steam become more and more favourable as the power output required from the tractive unit decreases, when the advantage of a self-propelled vehicle, such as a railcar, over a train hauled by a locomotive becomes more pronounced.
Heat Loss from Gilled Metal Pipes
Authors: Griffiths Ezer , Awbery J. H. 
Published: October 2007

In a previous paper, on “Heat Transfer between Metal Pipes and a Stream of Air”, presented to the Institution in 1933, an account was given of measurements on the transfer of heat between plain pipes and a stream of air. The present paper is an extension of this investigation to gilled pipes. Observations have been made on the heat loss from four gilled pipes of diameters between 1 and 2½ inches, with gills varying in diameter from 2 to 4⅓ inches. Each pipe was studied as a single unit in the wind tunnel, whilst one size of pipe was also examined when built into a battery of similar pipes placed with their axes across the direction of the air flow. The result found for plain pipes, namely, that H/ κ θ is a function of V d/ v only (where H is the heat loss per unit length from a pipe of diameter d at a temperature excess θ over air of thermal conductivity κ and kinematic viscosity v, moving at velocity V), requires modification in the case of gilled pipes. In the former case, H is the heat loss per unit length, and is thus equivalent to the product of the circumference and the heat loss per unit area. The latter interpretation, when dealing with the results for the gilled pipes, does not give systematic results, if the heat loss per unit area is calculated on the total exposed area of the pipe. Moreover, in defining the surface emitting heat, the quantity d, the pipe diameter, is only unambiguous for plain pipes. In the case of gilled pipes, it is found that the most consistent treatment of the results is obtained if d is taken to be the “effective diameter” of the pipe, i.e. the total exposed area per unit length divided by π If the interpretations just explained are given to the quantities H and d, then it is found that to a first approximation, the relationship between H/ κ θ and V d/ v is the same for a gilled and a plain pipe. The observations have also been analysed from the point of view of the temperature of the edge of the gill, relative to that of the air and that of the pipe.
Impact Stresses in a Freely Supported Beam
Authors: Arnold R. N. 
Published: October 2007

The paper reviews various theories used in estimating impact effects on a freely supported beam, and points out the error which may be introduced if the assumption is made that elastic forms are similar under dynamic and static loading. An apparatus is described, in which the beam is a railway rail of 8 feet span, subjected to central impacts, strain measurements being made along the flange by means of small scratch-extensometers. An analysis of records from these instruments gives an indication of the instantaneous bending moment distribution occurring at time intervals of 1/1,000 second during impact, and the bending stresses are shown to be approximately 20 per cent greater than those calculated by assuming “statical equivalence”. The variation of load between weight and beam during impact is recorded by the vertical strain of the rail web under the load, and a complete series of records for various weights and velocities is given. These records demonstrate the occurrence of “sub-impacts”, the weight in certain cases striking the rail five times under what the human eye observes as a single impact. Diagrams of results obtained by calculation from an equation derived by Timoshenko show agreement in form with the load variations recorded by the scratch extensometers. Results obtained by measurement from the area of the ellipse of contact are also given, and loads—obtained by four independent methods—are drawn to a base of impact velocity for various weights. The experimental results are shown in all cases to be at least 2½ times those predicted by the assumption of “statical equivalence”, and (allowing for calibration difficulties) are in fair agreement with those obtained from the Timoshenko equation. Mention is made of the practical significance of the results.
The Development of Single-Bucket Excavators
Authors: Savage W. 
Published: October 2007

Since the presentation of the last paper on excavator practice to the Institution by F. H. Livens, M.I.Mech.E., and W. Barnes, M.I.Mech.E., in 1920,† a great many changes have taken place in both the application and design of excavating machinery. The application of this type of machinery has been dealt with on several occasions during the intervening years, and as recently as December 1934, Sir Henry Japp dealt very fully with “Modern Methods and Plant for Excavations” in a comprehensive paper read before the Institution of Civil Engineers.‡ This paper therefore deals more particularly with the progress in design of the excavator itself rather than its application. Attention may first be drawn to the extension of the range of sizes available in both directions. In 1920 machines carrying dippers of 6 cu. yards capacity and weighing about 250,000 lb. represented the upper limit in size, whilst machines carrying dippers of [Formula: see text] cu. yard capacity were the smallest available. In 1937 machines having dipper capacities of as much as 33 cu. yards and weighing 2,500,000 lb., or as little as [Formula: see text] cu. yard and weighing 15,000 lb., were manufactured. A greater number of distinct types have also been developed. Twenty years ago types in common use were the shovel and the grab or clamshell. To-day, drag-line, drag-shovel, and skimmer-scoop equipments are largely used, and these have been developed to meet the growth of application of the single-bucket excavator, enabling it to do work for which it was originally unsuited. In 1920 steam was practically the universal motive power, but this has given way to the internal combustion engine and electricity, and is now virtually obsolete for this purpose.
Aircraft Efficiencies
Authors: Piercy N. A. V. 
Published: October 2007

The past seven years have witnessed remarkable developments in aircraft. They have marked the advent, for example, of autogyros, cantilever monoplanes, landing flaps, variable-pitch airscrews, and retracting undercarriages. Equally apparent to engineers will have been the perfection of powerful and compact engines weighing little more than 1 lb. per h.p., the adoption of skin stressing and ducted cooling, the shrinkage of wing area until nearly twice as much load is carried per square foot, and the elimination of exposed struts, wires, levers, and rivet heads. Speeds have advanced greatly with little sacrifice in flying weight per brake horse-power or in useful load. Thus there has occurred a very notable increase in the efficiency of aircraft, exercising a profound influence on aerial transport. Many methods of construction, which have been especially devised to meet stringent conditions as regards economy in weight, should also find application in other high-class engineering productions. Again, the new knowledge of fluid motion and matters associated with it, constituting the engineering science of aerodynamics, must eventually prove of service in hydraulics, heat transfer, ventilation, and kindred subjects. In the paper some of the main considerations affecting the efficiency of aircraft are described. Exhaustive discussion would form too comprehensive a subject, and it has been decided to consider especially those factors in which fluid motion plays a prominent part. Where possible, however, the treatment takes into account structural and other efficiencies attainable in given circumstances. The point of view adopted is that of civil transport, where efficiency is most urgent. Discussion will turn essentially on speed and, in justification, it may be remarked at once that ( a) speed is exceptionally important in the air since the drift of head winds must be subtracted in full, and ( b) high speed is the prerogative of aircraft, being in the nature of things most economically and safely attained in their case.
Some Problems in the Transmission of Power by Fluid Couplings
Authors: Sinclair Harold 
Published: October 2007

The paper deals with some of the problems that arise in the transmission of power by fluid couplings working on the Föttinger principle in connexion with internal combustion engines and electric motors driving a variety of loads. The influence of the core guide ring on the torque and speed characteristics in fluid couplings of the variable-filling type is considered, and an indication is given of the changes in thrust as the filling of the working circuit is varied. Considerable progress has been made towards the simplification of auxiliary means for controlling the quantity in the working circuit. Particulars are given of several methods of dealing with the residual or drag torque in fluid couplings of the constantly filled type, for use with change gear drives. Slip curves relating to backward curved impeller vanes illustrate the variations between theory and practice in this case. Methods of mounting couplings on engine crankshafts and arranging outboard or driven shaft bearings are illustrated, and a variety of applications of fluid couplings are considered from the aspects of heat generation and dissipation. The internal forces in the ring valve type of fluid coupling may be utilized to close the valve automatically in order to disconnect the drive in case of overload.
Measurement of the Fineness of Powdered Materials
Authors: Heywood Harold 
Published: October 2007

The paper describes in detail the methods of analysis at present available for measuring the fineness of powdered materials used in engineering and industrial processes. Definitions of particle size and shape are discussed, and examples are given of the size-distribution curves for typical industrial powders. Sieving or screening is used for the size grading of the comparatively coarse particles, and processes involving motion in a fluid for particles smaller than the limit of sieving. The theory of sieving and the relationship between particle size and sieve aperture are discussed. The equivalent sizes of round, square, and slotted apertures have been measured and results are given. The motion of irregularly shaped particles in a fluid is briefly described, and a method is given for calculating the falling velocity of such particles when the fluid flow round the particles is turbulent. The procedures used for the fineness analysis of sub-sieve particles are: elutriation by means of air or water, sedimentation, hydrometer readings, and the obscuring of a beam of light by dilute suspensions of the particles. Each of these processes is fully described, and the respective merits and disadvantages discussed. Tables of the nominal apertures of all the standard sieve series in industrial use, and a bibliography of about 150 references are included in the paper.
Observations on the Arc Welding and Gas Cutting of High-Tensile Low-Alloy Structural Steels
Authors: Wilkinson T. B. , O'Neill Hugh 
Published: October 2007

High-tensile structural steels generally contain relatively small additions of alloying elements which affect their welding properties because of hardening effects. The paper gives data regarding the composition and test values of some typical high-tensile steels, together with results on metallic-arc welded joints. Laboratory cracking tests to determine the weldability of steel plate are described, and their utility is demonstrated. The composition and inherent grain size of the steel, together with the conditions of welding, affect the properties of the heat-transformed zone. It is desirable to limit the carbon content to 0·20 per cent; and for single-run fillets the use of a relatively slow welding speed of 4–6 inches per minute, with a fillet size of not less than half the thickness of the plate, has given the best results in the authors' work. The properties of various covered electrodes have been studied. Carburization experiments on all-weld metal reveal interesting differences between electrodes. The cutting of these steels by gas is considered, in so far as most of the factors influencing weld hardness may operate, to produce cut edges having hard surfaces of reduced ductility.
Transatlantic Air Transport with Particular Reference to Flying Boats
Authors: Gouge A. 
Published: October 2007

Until within the last few years the efficiency of the aeroplane was such that Atlantic crossings were made under hazardous conditions with very much overloaded machines carrying no pay load. In 1937 and 1938 a number of survey flights were carried out with considerable success, and there is no doubt that the performance of the modern aeroplane makes the direct route practicable. The author outlines several designs for aeroplanes and seaplanes for a transatlantic service, and is of opinion that, largely on account of take-off and landing problems, flying boats will be used. Consideration is given to the influence of improvements in materials, high-altitude research, and the compression-ignition engine on the future development of large transatlantic flying boats.
Some Problems in the Design and Operation of Merchant Vessels
Authors: Lee Robert C. 
Published: October 2007

This, and the following American papers by Mr. Ripley, Mr. Horner, and Mr. Allen are reprinted by permission of the American Society of Mechanical Engineers. They were to have been discussed in conjunction with the four preceding English papers at the Joint Meeting in New York, which was cancelled owing to the outbreak of war. This paper presents certain technical aspects of ship design and operation as viewed from the standpoint of the executive administration of the merchant marine. The author evaluates the recent developments in hull and machinery design and construction in terms of economics. From the records of the Scantic Line and the American Republics Line, operating cost figures are cited to demonstrate the relation of the various factors involved in ship operation. A review of shipbuilding costs and sales values of ships is included. Among other important matters discussed in the paper are safety provisions, crew training and personnel relations, and finally mention is made of the need for better and more efficient methods of cargo handling. The problems are proposed, as the author states, without solutions being available for many of them, in the hope that subsequent discussion may develop appropriate answers.
The Horizontal Carriage of Granular Material by an Injector-Driven Air Stream
Authors: Wood S. A. , Bailey A. 
Published: October 2007

Pneumatic conveyance is coming into increasing use in industry. The investigation described was intended to explore general principles. Tests were made with an experimental horizontal conveyer, using sand and linseed respectively as the materials conveyed. The air stream was maintained by an injector with an annular high-pressure nozzle surrounding the conveyer pipe. The grains were allowed to fall into the air stream at the inlet, and were collected in separators at the outlet. The test results showed that there is a definite optimum position for the injector in the pipe line, and that it is an advantage to use a divergent diffuser at the outlet end. Definite relations were also found to exist betweeen ( a) the air velocity and the rate of conveyance of solids, ( b) the pressure gradient in the pipe and the injector pressure, and ( c) the additional pressure drop due to the grain and the rate of grain conveyance. There are indications that the effective coefficient of friction between the grain and the pipe falls as the grain velocity increases; this conclusion is borne out by visual observation, which shows that the path of a grain consists of a series of leaps, whose length increases with the grain speed.
The Examination and Tests of Welded Parts for Steam Power Plant
Authors: Goodger A. H. 
Published: October 2007

The object of the paper is to give the results of certain experimental and routine inspection work rather than to lay down rules of inspection and testing. An outline is given of the margin obtained between some of the properties and requirements of actual drums and the specified limits. European practice appears to favour acetylene welding for the butt welding of tubes. Normally acetylene welds do not suffer from basal cracking, but they do suffer from lack of penetration; the paper gives methods by which this can be avoided, and suggests forms of joints for tubular welds. The inspection of tubular welds presents many problems, but certain non-destructive tests have been successfully applied, and a number of X-ray examinations on site are described. A useful method of inspecting large numbers of tubular welds by sample consists in carrying out a reverse bend test on a tongue sawn out of the tube and pressed round a former. The paper also contains the results of extensive experience of the heat treatment of welds on site.
Vortex Pumps, or, Slip in the Centrifugal Pump
Authors: Price Owen A. 
Published: October 2007

The current theory of the centrifugal pump does not correspond with its actual performance; it suggests a reserve of 30–50 per cent of pumping capacity available to the designer. The author questions the existence of this margin and examines the energy of rotating bodies of fluid. All flowing vortices must be “hollow” to permit of a continuous admission of fluid at their centres, and the energy expressions are adapted accordingly. No discrepancy is found between the performance of a selected centrifugal pump and its corresponding hollow vortex. In order to test this conformity under widely differing conditions, test performances of pumps of different design are examined. The examination reveals limitations to this conformity. By analogy with other forms of slip, a “slip ratio” is defined and employed to relate pump and vortex theory, the pump theory representing the capabilities of the vane and the vortex theory the performance of the pump. Emphasis is placed upon the importance of studying the physical properties of the moving fluid rather than the potentialities of the actuating vane.