bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plastic Yielding and Fatigue of Ductile Metals. A Criterion and Its Application
Authors: Bailey R. W. 
Published: October 2007

Based upon a hypothesis of surface anisotropy of an otherwise isotropic material, a criterion of the yielding of a ductile metal is suggested which embraces the several well known criteria as special cases. This criterion for a system of principal stresses X, Y, Z (= 0) takes the form [Formula: see text] = constant; or [Formula: see text] = constant, which for component shear and direct stresses, q and f respectively, becomes[Formula: see text] = constant, where f/q must fall in the range √2 to 2. The proposed criterion is considered to be applicable in character to fatigue of a ductile metal, and it is applied to derive, from direct and shear stress fatigue test results, limiting fatigue stresses for any combination of shear stress and direct stress in phase, which is the most severe condition. Analysis indicates that the presence of static shear stress may increase the ability of a steel to withstand reversing direct stress. Apparently an opposite effect occurs when direct stress fatigue test results conform to the Goodman or modified Goodman diagrams.
Fuel Economy in Petrol Engines
Authors: David W. T. , Leah A. S. 
Published: October 2007

Charts are given in this paper from which may be found the indicated thermal efficiencies, the fuel consumption per indicated horse-power-hour, and the mean effective pressures which are practically attainable in a compact combustion-chambered petrol engine of any bore between 3 inches and 8 inches when running at any compression ratio between 4/1 and 9/1 and at any speed from 1,000 r.p.m. upwards on an octane, ethyl alcohol, or benzene-air mixture of any strength between 20 per cent weak and 20 per cent rich. From these charts similar information in regard to any mixed petrol may be deduced with fair accuracy. The performance of actual engines is compared with the attainable performance in the light of views, given in some detail, relating to phenomena associated with the working fluid and the combustion of the charge. The conclusion is that improvement in charge mixing within each engine cylinder would lead to better performance. Characteristic merit and demerit curves are suggested which appear to be capable of yielding useful information in regard to the functioning of engines.
Fuel Injection in Oil Engines in Relation to Combustion
Authors: Green G. W. A. 
Published: October 2007

The object of the paper, which deals with the jerk pump injection system, is to show the relationship between the design of fuel injection equipment and the design of the engine on which it is used. First the nozzle is considered as an orifice, in its relation to the combustion chamber, and an account is given of the features of hole type and pintle type nozzles. The action of the differential needle valve is then discussed, and particular reference is made to the design features necessary to ensure quick action of the valve, with good “chattering”. The author then considers the design of “restricting” or “delay” type nozzles, and a description is given of the delivery valve of the pump. The need for “unloading” of the delivery pipe is discussed, together with various types of delivery valve and their action. The delivery pipe itself is treated with reference to ( a) determination of size of pipe; ( b) pipe surges and their effects; ( c) methods of dealing with surges. In addition the action of a pump plunger and barrel of the ported type is considered in relation to its effect on pump output at varying speeds, also the combined effect of pump plunger and delivery valve. The author sets out the points to be considered in the selection of fuel injection equipment for a given engine. Basing his analysis on existing designs, he puts forward a classification of combustion chambers from the viewpoint of fuel injection. He shows that orifice diameter in hole type nozzles depends on the penetration required, and that the total orifice area is also dependent on the piston displacement per unit of time. The selection of a suitable pump to feed the nozzle is discussed, and the author arrives at specific ratios for assessing pump action in relation to the engine and the nozzle. Finally, consideration is given to the limiting capacity of an atomizer of given size, and to the release pressure in an atomizer and the maximum pressure of injection.
Properties of Steels as a Basis for Design for High-Temperature Service. Part I: Carbon Steels
Authors: Tapsell H. J. , Johnson A. E. 
Published: October 2007

The paper gives a brief account of the influence of stress, temperature, and time on the behaviour of carbon steels of about 0·15 to 0·50 per cent carbon content, and provides data as a basis for design purposes. The data given are derived from investigations carried out at the National Physical Laboratory, largely on behalf of the British Electrical and Allied Industries Research Association. Although practice has established satisfactory working stresses for carbon steels at moderately elevated temperatures—possibly up to 425 deg. C. (800 deg. F.)—it may serve a useful purpose to include herein particulars of the strength of carbon steels up to 800 deg. F. The chief purpose of the paper, however, is to assist the reader in appreciating the factors involved in estimating the useful strength of steels at higher temperatures extending to about 1,000 deg. F.
Fatigue Tests of Structural Steel Flats and Bars Cut from Butt-Welded Boiler Plate
Authors: Lea F. C. , Whitman J. G. 
Published: October 2007

The paper describes the results of repeated stress bending tests to determine whether the resistance of welded plates to repeated stresses depends on the size of the plate, or in other words, if there is a “scale effect”; and to compare the results obtained from welded plates with those from plates with holes drilled in them. The tests were carried out in the bending machine‡ designed by one of the authors. In the second§ and third‖ reports of the Welding Research Committee the results of repeated stress tests on -inch butt-welded plates and on 3-inch butt-welded plates had shown that from the smaller butt-welded plates a higher fatigue range from zero minimum stress had been obtained than from the 3-inch butt-welded plates. A detailed examination of the welds did not indicate a satisfactory explanation of the difference, and it appeared desirable, therefore, to make further tests on specimens of various thicknesses to determine whether the lower fatigue range was due to the size of the specimen. The results given in the paper show that for specimens from 1 inch to 3 inches in thickness made in three different works no scale effect is indicated. The tests made on drilled plates confirm others previously carried out, and show that drilling a hole in a plate reduces the fatigue range load very considerably. The results from the thick welded plates show that with well-controlled welding, fatigue ranges for the welds as high as those from the black plate can be obtained.
Some Notes on Printing Machinery
Authors: Skeat W. O. 
Published: October 2007

After a preliminary section dealing with type and type faces in general, and the methods of generating the matrices from which letters are cast, the author describes the machinery used in the two broad divisions into which the work of producing a printed page can be divided: ( a) composing and typecasting; and ( b) actual printing, or “machining”. The paper deals only with the machinery used in the production of the Proceedings of the Institution. Composition is carried out on Monotype keyboard machines, provided with groups of keys, arranged like those on a typewriter; the keys when depressed cause perforations, varying with every key, to appear in a paper roll fed through the machine. The finished roll, looking like a pianola roll, is then “played” on the typecaster and the perforations in it form a code which virtually gives instructions for the fresh positioning of the matrix case for each letter cast. The galleys of newly cast type emerge from the caster, are divided into page lengths, and assembled as complete pages in “formes” which are then taken to the printing machines. The press used for this work is of the “two-revolution” pattern, printing the sheet during one revolution and delivering it during the next. The mechanism for reversing the bed is described, also the special arrangements for feeding the sheets to the machine.
The Physical Aspect of Steam Generation at High Pressures and the Problem of Steam Contamination
Authors: Davis R. F. 
Published: October 2007

The constitution and the physical properties of boiler water are investigated with reference to the operating pressure. The process of evaporation at a submerged heating surface is examined and it is shown how nuclear boiling is the normal mode of evaporation, but that under certain conditions film boiling may take place. The size of the steam bubbles generated bears a definite relationship to the characteristics of the heating surface and the operating pressure. During migration from the heating surface to the free water level, the steam bubbles experience rapid growth at low pressures, but a negligible amount of growth at high pressures. The effect of bubble size on circulation is discussed. At high pressures the steam bubbles are very small and the presence of salts in the boiler water tends to inhibit their coalescence. Small steam bubbles throw up minute drops of water upon disruption into the steam space. The height to which the drops rise above the water level depends on the operating pressure and the rate of steam release; the drops become entrained with the steam at a certain critical rating, causing wet steam. Foaming is another cause of wet steam and is found to depend on the physical state of the suspended solids in the boiler water. Mechanical priming and methods of preventing steam contamination by moisture and solids are also discussed.
The Mechanical Requirements of the Royal National Lifeboat Institution
Authors: Johnson P. H. 
Published: October 2007

After dealing briefly with the historical and general aspects of the subject, the author touches on the disposition of lifeboats round the coast and the factors which govern this distribution. Details of the boats themselves and their equipment are not given, but the paper concentrates on the difficulties involved, and the methods and equipment employed, in launching from the beach. Certain difficult beach conditions have been met by mounting the 11 tons of lifeboat and carriage on track units of the rigid girder type. Reference is made to the wheels employed in launching lighter boats in the past. Excessive rolling resistance made these wheels impracticable for soft beaches. The relationship between rolling resistance and the width and diameter of steel-tyred wheels is given, together with a description of the girdled wheels devised some forty years ago by Commander Gartside-Tipping, R.N. The development and construction of the girder track units now employed in place of wheels is fully dealt with. The method of launching a lifeboat by tractor is described, and shows how necessary are extreme reliability and watertightness in the tractor employed. The lifeboat “roadless” tractor is then described in detail and particulars given of the methods by which it is made waterproof. Special mention is made of gear for extracting the tractor from quicksand or mud pockets, and a résumé is given of the experience gained in this direction with tanks during the war of 1914–18. An alternative method to that adopted for waterproofing the tractor is referred to. A summary is provided of the submergence and other tests to which the tractor is subjected and of the special precautions which are taken in service to prevent trouble arising from internal corrosion due to condensation. The paper closes with the possible applications in other directions of the experience gained with the machinery described.
The Dynamic Absorber and its Application to Multi-Throw Crankshafts
Authors: Bailey S. B. , Bulleid C. H. 
Published: October 2007

The dynamic absorber is the special case of a tuned absorber in which the natural frequency of oscillation is directly proportional to the rotational speed of the shaft which carries it. Four typical absorbers are studied in detail; in each case, the tuning and amplitude equations are derived and, for the roller types, expressions are obtained for the maximum roller amplitudes which may be attained without the occurrence of slipping. As with the simple tuned absorber, the dynamic absorber may be used to prevent resonance with one torque harmonic, and will operate satisfactorily so long as it is connected to the main system at the point of application of this exciting torque. There is therefore no difficulty in fitting such an absorber to a single-row radial engine in which all the exciting torques act at one crank throw. An engine having a multi-throw crankshaft presents more difficulty, as it is necessary to determine how many absorbers to fit, and the manner in which the stabilizing torque is distributed between these absorbers. Such a case is fully analysed, and examples are given of the application of dynamic absorbers to a typical multi-throw aero-engine crankshaft. The method is quite general, and can be applied to any other type of engine as desired.
Heat Transmission in Surface Condensers
Authors: Petty Thomas 
Published: October 2007

The paper deals with the resistance to heat flow on the steam side of surface condenser tubes, and begins with a brief reference to theoretical and experimental work on the subject. The separation of the total resistance from steam to water into its component resistances and the estimation of the resistance from steam to tube by the remainder method is then discussed, an example of the procedure used by the author in the preparation of the paper being given in Appendix I. The probable factors in the conditions of operation which produce the variations observed in apparent resistance to heat flow from steam to tubes, as estimated by the remainder method from the results of condenser tests, are then considered. The validity of the assumptions made with regard to these factors is tested by a re-examination of the results of four well-known condenser tests in which the amount of air leakage was recorded. The conclusions and observations to which this examination would appear to give rise are then stated. An alphabetical list of references is given in Appendix II.
Munitions Labour Supply Organization
Authors: Denholm W. H. 
Published: October 2007

The author reviews the effect of the war effort on the demand for skilled labour, and points out that the question of its proper distribution has been met by the establishment by the Ministry of Labour and National Service of an Inspectorate of Labour Supply, and Labour Supply Committees. The Inspectorate form the direct contact between the labour supply organization and the factories, and have the function of ensuring the efficient use and distribution of labour in essential industries. Their principal duties are to examine demands for skilled labour, taking into account any possibilities of the redistribution of skilled workers, the upgrading of semi-skilled workers, or the subdivision of processes. They also determine whether skilled labour can be released, and stimulate training by employers. Further duties are concerned with the Undertakings (Restriction on Engagement) Order, and the Conditions of Employment and National Arbitration Order, 1940. The author discusses the complex nature of the investigations which are undertaken in order to direct labour to work at which it is best used in the national interest. Where difficulties arise in the transfer of labour they are referred to the Labour Supply Committees, which deal with the general field of labour supply in their respective areas, and not only assess the relative urgency of demands for labour, but also stimulate arrangements for welfare and training. A section of the paper deals with training in training centres, technical colleges, and in factories, as well as with the training of apprentices and women supervisors. The author concludes with some notes on Area Boards, and puts forward suggestions to manufacturers with the object of accelerating progress in the work of labour supply.
The Fundamental Principles of the Steam Ejector
Authors: Royds R. , Johnson E. 
Published: October 2007

The main purpose of this paper has been to express experimental results in a form which reveals the fundamental principles for application to the design of ejectors. Notwithstanding the large losses of work energy in the nozzle, combining cone, and diffuser, the diffuser was found to obey the same laws of discharge as in convergent nozzles, although with a different constant. At the best nozzle settings, if P is the ejector outlet pressure, the position at which the pressure reached the adiabatic critical value P c = 0·55 P occurred at nearly the same point in the diffuser at maximum efficiency for wide variations in the working conditions, and for different forms of combining cone and diffuser throat. Also, the calculated area a c of the stream at this point was practically independent of the same factors. The position of the mouth of the nozzle had a predominant effect on the performance and efficiency, and the best nozzle positions were found to be nearly independent of the dimensions of the nozzle, the weight of steam and air flow, and the dimensions or form of the combining cone and of the diffuser throat.
The Regenerative Cycle: An Efficiency Basis having Special Reference to the Number of Feed Water Heating Stages
Authors: Horsman H. S. 
Published: October 2007

The efficiency of the regenerative cycle may be defined as the ratio of the heat converted into work (in British Thermal Units per pound of steam) to the heat supplied to 1 lb. of steam in the boiler plant. Where feed heating is employed, however, the heat converted into work is less than the adiabatic heat drop as calculated from the initial and final states of expansion. The difference between these quantities is termed “unavailable heat” in the paper, and the efficiency is therefore given as the ratio of the adiabatic heat drop less the unavailable heat, to the heat supplied to 1 lb. of steam in the boiler plant. The object of the paper is to illustrate the advantage derived from working in terms of unavailable heat. Values of this quantity are given, and the author provides a worked example showing their use. Appendixes I and II deal with investigations of the case in which the number of feed heating stages is infinitely great, i.e. the conditions for the ideal efficiency. The relationship of the ideal efficiency to other efficiencies corresponding to various finite numbers of feed heating stages is indicated.
II. Report on Austenitic Cast Irons
Authors: Pearce J. G. 
Published: October 2007

Austenitic cast irons may be regarded as bearing the same relation to ordinary cast irons as some of the stainless steels bear to the ordinary steels. Although more expensive, both in raw materials and manufacture, the austenitic cast irons have properties which mark them off as different from all other cast irons, particularly in their softness and ductility; high resistance to wear, erosion, corrosion and heat; non-magnetism and relatively high electrical resistance; low thermal conductivity and high thermal expansion. Their mechanical properties compare with those of a good engineering cast iron, but their softness and toughness make them readily machinable. They are readily welded. They are not susceptible to ordinary heat treatment, i.e. quenching and tempering, but nevertheless can be annealed at low temperatures with advantage. They can be cast white if required, and a simple thermal treatment such as annealing at 950 deg. C. for 30 minutes yields a metal with 2–3 per cent elongation in the cold. While the founding of these irons presents special problems, these can be overcome and the smallest castings can be, and are, successfully made in austenitic irons, down to -inch section; but if thin sections should be hard, they can be softened by the treatment given above. They melt at about 1,150 deg. C., a figure similar to that of the non-phosphoric cast irons, and have a specific gravity of 7·2–7·6. The present report is intended primarily as a guide to the engineering properties of the austenitic cast irons, in order that engineers may use them to the fullest extent justified by their properties. The data presented are drawn from authoritative sources, and a list of the papers and reports consulted is given at the end. In general, the data are those of interest to the user rather than the maker, to the engineer rather than the metallurgist.
Bench and Field Tests of Vehicle Gas Producer Plant as Applied to Farm Tractors
Authors: Bowden A. T. , Freeth E. E. , Rutherford A. D. 
Published: October 2007

During the past three years producer gas plants suitable for vehicles have been manufactured and marketed by several firms in Western Australia, to an extent that over seven hundred agricultural tractors in that State are now working successfully on producer gas. Australia as a whole, and Western Australia in particular, is fortunate in possessing large areas of hardwoods eminently suitable for making high-grade charcoal. As a consequence, producer gas development in Australia has been largely confined to the charcoal-burning type of producer. The present investigations were undertaken by the Mechanical Engineering Department of the University of Western Australia under the direction of Dr. Bowden, then Associate Professor of Mechanical Engineering, the object being to obtain information relating to the performance of producer-powered tractors. Funds for the purpose were made available by the Commonwealth Government of Australia through the Council for Scientific and Industrial Research. Experimental stations were established at Kellerberrin, and at Cranmore Park near Walebing. At the former, trials were conducted using two types of producer gas plant (the “Powell” and the “Herbert”), and two types of tractor (a “Case 12–20” and an “Allis-Chalmers” model “U”). Considerations of space allow of only brief reference to the trials carried out with the latter tractor. At the Walebing station a standard “Fordson 14–26” tractor was used in conjunction with “Powell” and “H.S.G.” producer gas plants. The results of the Kellerberrin trials are recorded in part I of the paper, and those of the Walebing trials in part II. A typical daily log sheet is reproduced in the Appendix.
Vibration in Power Station Steam Pipework
Authors: Cowlin F. J. 
Published: October 2007

In recent years vibration in steam pipe lines in power stations has been of more frequent occurrence, causing in one or two cases a temporary limitation of the load-carrying capacity of the plant until the trouble could be either minimized or eliminated. The present report summarizes the information collected by an exhaustive inquiry covering all the present available sources of information. It deals with the prevalence of the trouble, its nature and effects, arriving at the conclusion that it is in some way associated with the use of corrugated piping, which has been increasingly used as a result of the more stringent flexural requirements of modern pipe layouts. The remedial measures so far employed are described; but these have been hampered by a lack of knowledge of the fundamental cause of the trouble and have been applied haphazardly. The conclusion drawn from the inquiry is that a prima facie case exists for special research being undertaken, but that it is difficult to see how it could be carried out at the present time. Suggestions are made regarding the form which the research work might take; but in the meantime the report is published in the hope that the additional publicity may result in further information being obtained, which will assist in the solution of a complicated and difficult problem.