bluuebunny/crossref_metadata_2025_split huggingface dataset:
Proneness to Damage of Plant through Enemy Action
Authors: Gutteridge Hal 
Published: October 2007

The aim of the paper is to draw attention to the facts which underlie the rapid approximate estimation of damage to plant through enemy action. Different items of plant will be affected to a greater or lesser extent depending upon their type and the conditions to which they have been exposed. Thus, a smith's anvil, at the one extreme, would be but slightly damaged by blast, fire, collapse of the building, falling debris, or flooding, if a direct hit or persistent fire was excluded. At the other extreme, delicate electrical apparatus would suffer severely if exposed to any of these conditions. In the case of the anvil the “damage proneness number” (d.p.n.) is likely to be between the limits of 0 and 5, whilst that of the latter may be between 80 and 100 in “average” cases where a direct hit or persistent fire did not take place. Thus all plant can be classified and given probable limits beforehand of the extent of damage, and it would remain for the trained observer to fix the damage proneness number which in exceptional cases might be outside the average limits. Expressed as a percentage of the value of the item, the damage proneness number would indicate the amount of the loss involved; the sum of the amounts of the individual losses would give the total approximate loss. The extent of the damage is affected also by the protection given by the building, the position of the item within the building, and by the type of bomb and its point of impact in relation to the item.
Caustic Embrittlement
Authors: Colbeck E. W. , Powell L. , Smith S. H. 
Published: October 2007

The paper contains the results of experimental work on caustic embrittlement. The type of apparatus chosen was based on one used in recent American work carried out by Straub and Bradbury (1938). In this, the solution to be tested is contained in a hollow sealed tubular specimen, heated to any desired temperature in the steam boiler range, and subjected to a tensile load by means of a spring. It has not been possible to reproduce the results claimed by Straub, but a number of examples of intergranular cracking have been produced. Some of these have been obtained when using dilute solutions containing amounts of NaOH and silicate such as would be found in boiler waters. There is evidence that embrittlement occurs more readily in poor-quality steel and under conditions of non-uniform stress distribution, but it has not been possible to reproduce results with any degree of certainty. A few experiments with an entirely different type of specimen have been carried out; and in these, intergranular failures have also been produced. The paper also contains a survey of the more important literature on caustic embrittlement published between 1935 and 1941.
The Soot Blower, with Special Reference to the Present Position of Power and Automatic Operation of Mechanical Blowers
Authors: Glinn R. J. 
Published: October 2007

The nature and extent of the deposits which occur on the heating surface of a boiler unit are variable in the extreme. The method of firing and the rate of combustion are open to choice. The completeness of combustion can be controlled to some degree, but the quantity and chemical constituents of the ash can seldom be forecast, and may vary widely. The form of fouling, and the effect on the different portions of the heating surface of the boiler unit, are examined. Development of the application of soot blowers from 1919 is discussed, particularly the use of the single-nozzle blower. The design of the boiler to permit full use of the different types of soot blowers available is referred to, and mention is made of the effect on furnace walls, boiler tubes, and superheaters, economizer, and air heater surfaces. The future design and rating of boilers depend to a great extent on the development of the means of cleaning the heating surface. Reference is made to cleaning by water lancing and other means for special cases. The importance of the availability of plant is emphasized, and essential features of power-operated mechanical soot blowers, with special reference to automatic operation, are outlined. The scope of use of the three main types of soot blowers is set out, as well as the essential features of their design. Points for consideration in the periods between individual soot blowing operations and the extent of each blowing, are enumerated, and in section (3) of Appendix I (p. 96) the types of automatic soot blowers on the market are briefly described; a general indication of the trend of modern design of blowers, both electrically and hydraulically operated, is also given.
Third Report of the Research Committee on High-Duty Cast Irons for General Engineering Purposes
Authors: Pearce J. G. 
Published: October 2007

The Third Report was originally projected as the Second Report,† but the necessity of making use, under war conditions, of the most readily available indigenous ores, caused the Committee to concentrate immediate work on the influence of phosphorus upon mechanical properties. The Second Report has already dealt with the influence of this element on the properties of the plain cast irons, whilst the Addendum to the Second Report‡ covers the alloyed cast irons. The Third Report contains in Part 1 further results on commercially made high-duty cast iron, i.e. those equivalent in properties to, or better than, grade 2 of British Standard Specification No. 786 (1938), and in Part 2 the results of the remainder of the experimental programme concerning alloy cast irons, showing the influence of additions of nickel, copper, chromium, and molybdenum, both severally and in various combinations, on certain selected compositions. Both parts of this Report refer to the machinable engineering cast irons, having a pearlitic structure with normal flake graphite, covered by class 11 of the classification§ given in the Reports on Special-Duty Cast Irons. The more recently developed so-called acicular cast irons, showing excellent mechanical properties, do not fall within this category, and are being made the subject of experimental work.
A Survey of Modern Centrifugal Pump Practice for Oilfield and Oil Refinery Services
Authors: Tetlow N. 
Published: October 2007

During the last thirty years there has been a manifold increase in the demand for centrifugal pumps for oilfield and oil refinery service, an increase in which British engineers have played a worthy part. With traditional British reticence little has been said of the achievements of British oil companies and British pump manufacturers in this field of activity, and the author has written this paper with the object of correcting the omission. In the field of oil transportation over long distances, for instance, the influence of British practice is to be seen in many oilfields throughout the world. Within the refinery considerable strides have been made, particularly in solving the difficult problem of handling unstable hydrocarbon liquids under high suction pressures. Hot oil pump practice is now more or less established, and in this development the greater share of credit is due to American pump manufacturers. These developments are dealt with at some length in the appropriate section of the paper. Another point which calls for comment here is the introduction of a new term, for the characteristic of flow into the impeller eye, which is used in section 3 of the paper. When dealing with hydrocarbon liquids under saturation pressure and temperature conditions, the so-called “suction performance” of a centrifugal pump becomes extremely important. As a description of this most important characteristic of a pump the use of the phrase “suction performance” is misleading, and it has led to much confusion of thought. An attempt has been made to reduce the possibility of further confusion by coining a new phrase based on the analogy of similar characteristics encountered in electrical engineering. Throughout the paper, therefore, the pump characteristic relating to flow into the impeller eye has been described as the characteristic of “flow inductance”. The paper would not be complete without an attempt to assess the future trend. There will probably be a much greater tendency towards electrification of main-line pumping plant. A further increase in operating temperatures and pressures will, no doubt, lead to many fundamental changes in the design of pumping plant for use inside the refinery. As an example, it is suggested that for some difficult duties it may be necessary to adopt pump designs in which stuffing boxes are avoided altogether. Finally, it is probable that refinery technologists will tend more and more to adopt chemical processes and chemical engineering practice, so introducing new problems for the pump designer.
The Calculation of Roll Pressure in Hot and Cold Flat Rolling
Authors: Orowan E. 
Published: October 2007

A numerical or graphical method is given for computing, in strip or plate rolling, the distribution of roll pressure over the arc of contact and the quantities derived from this (e.g. the vertical roll force, the torque, and the power consumption). The method avoids all mathematical approximations previously used in the theoretical treatment of rolling, and permits any given variation of the yield stress and of the coefficient of friction along the arc of contact to be taken into account. It can be used, therefore, in both hot and cold rolling, provided that the basic physical quantities (yield stress and coefficient of friction) are known. The usual assumption that the deformation could be regarded as a locally homogeneous compression has not been made, and the inhomogeneity of stress distribution has been taken into account approximately by using results derived by Prandtl and Nádai from the Hencky treatment of two-dimensional plastic deformation. It is found that the discrepancy between the roll pressure distribution curves calculated from the Kármán theory and those measured by Siebel and Lueg is due to the assumption in the theory that the frictional drag between the rolls and the rolled stock is equal to the product of the roll pressure and the coefficient of friction. If frictional effects are dominant, as in hot rolling, this product may easily exceed the yield stress in shear which is the natural upper limit to the frictional drag, and then static friction, instead of slipping, occurs. This has been taken into account in the present method, and the calculated curves of roll pressure distribution show good agreement with the curves measured by Siebel and Lueg.
The Hydraulic Operation of Lathes for the Production of Shells
Authors: Philip W. Littlejohn 
Published: October 2007

The paper is limited to the application of hydraulic power to lathes designed for shell making although, in the author's opinion, there is an immense field for the application of the same principles in other directions. Self-contained hydraulic machine tools have been dealt with by Mr. H. C. Town,† but in the system to be described all the machines are operated from a central hydraulic plant. Three complete installations on this principle have been established by the author, and the present paper contains an account of this work from the first experiments in 1915 until about four years ago. The first plant was constructed in 1915 for the production of 3·29-inch shells, known as “18-pounders”, from the solid bar. The output was 2,000 shells per week of 135 hours, with girl operators working on three shifts. The second plant was put down in 1916–17 for an output of 500 9·2-inch howitzer shells per week of 135 hours, also with girls working on three shifts. The third plant is of recent design. It was started in 1938 for the production of 3·45-inch shells, known as “25-pounders”; and was laid out for an output of 1,000 shells per week of 47 hours. This plant included four types of hydraulic lathes which the author was engaged to design for the War Office. Soon after the commencement of the last war in 1914 it became evident that shell production would have to be greatly increased, and engineering firms were pressed to take up shell manufacture. The author, on behalf of his firm, undertook to help in the movement, and he at once set about the construction of some simple machines for the job. These conformed on general lines to the practice of the period as regards design and operation. He soon realized, however, that drastic changes would have to be made if production was to reach the high level that circumstances demanded. Although quite familiar with hydraulic machinery of various types and of many applications in presses and certain types of heavy tools, he was not aware of any instance in which hydraulic power had been applied to the movements of a lathe. It appeared to him, nevertheless, that it would be possible to construct a very useful machine on these lines, and he accordingly started immediately to carry out experiments and to prepare designs. It was considered essential that machines for the duty which the author had in mind should be much heavier and more rigid than the ordinary machines of the time, so that they should be free from vibration and “chatter” or spring with the heaviest possible cutting. The standard of rigidity aimed at was that which would permit a half-crown coin to remain balanced on edge on the moving saddle or turret while the tools were making the heaviest cuts. This object was achieved, and the demonstration was frequently made in the presence of those who came to see the lathes at work.
The Abnormality of Flame Gases
Authors: David W. T. 
Published: October 2007

Hot gases formed as a result of combustion behave differently from normal hot gases of similar composition, and it is believed that a full appreciation of this fact would lead to the opening up of a wide field of profitable research. Experiments are described in the paper which show that flame gases hold within them a long-lived latent energy. It has been found that the latent energy may amount to as much as, or even more than, 15 per cent of the heat of combustion; but it varies greatly with the conditions under which combustion takes place. These conditions have been investigated by means of explosion pressure and heat loss measurements, flame gas temperature measurements, and flame photography. Experiments are also described which show that in virtue of the latent energy an abnormally large amount of dissociation may obtain in flame gases. On account of this, a platinum wire immersed in flame gases may attain a far higher temperature (some hundreds of degrees Centigrade higher) than a similar wire coated with quartz, and this cannot be accounted for in terms of the different emissivities of the surfaces. There seems little doubt that this phenomenon may have an important bearing upon such problems as the transmission of heat from flame gases and the selection of gas fire radiants. Flame gases resulting from the combustion of weak hydrogen-air mixtures behave in a quite exceptional manner and a short account of some experiments with these gases is given in Appendix I, p. 243.
Static and Clinging Friction of Pivot Bearings
Authors: Hunter M. C. 
Published: October 2007

The author points out the clear distinction which has to be drawn between kinetic and static friction, and describes the special apparatus used in the investigation carried out to determine the static friction of various combinations of metals, including stainless steel and duralumin, under several conditions of dry and viscous lubrication. The paper stresses the effect of time, and gives data showing the rapid growth of the coefficient of friction during the first twenty-four hours at rest, and the subsequent increases over a period of five days. A series of long-term tests of thirty, sixty, and ninety days, on a selected number of specimens, provides a direct comparison from which the relative merits of the various combinations of materials is drawn. Evidence is provided suggesting advantages to be derived from the use of graphite as a preventative of clinging friction. In conclusion, an explanation is put forward as to the possible causes responsible for the building up of friction with the passage of time.
Marking Methods and War Production
Authors: Throp Arnold 
Published: October 2007

The paper begins with a citation of the regrettable lack of appreciation, amongst engineers generally, of marking as a production operation necessitating careful planning and tooling. It continues with an appeal to conserve the sadly overstrained capacity of the marking device industry by observing the following points. First, different classes of marking should be separated according to their respective purposes, and unnecessary classes should be eliminated. Second, the design of marking devices should be left to those who have made it their especial study; and thus, by avoiding the many pitfalls of a technical nature which few draughtsmen have had an opportunity of considering, the inefficient utilization of highly skilled labour, the unduly heavy consumption of marking tools due to premature failures, and the production of poor quality work will be prevented. Third, the attention of designers of aircraft, ammunition, and the other components should be directed to a consideration of marking processes before specifying the positions and surfaces on which marking is to appear and the form it is to take. Finally, the paper illustrates the possibilities of marking awkwardly shaped components, the production of accurate scales, the endurance of marking dies, and the rates of output that can be achieved. Numerous photographs and diagrams of representative methods and equipment are included.
The Thermal Rating of Worm Gearboxes
Authors: Walker Harry 
Published: October 2007

The paper deals with the factors affecting the temperature rise of totally enclosed self-lubricated gearboxes, with particular reference to worm gearboxes, and is based on observations obtained from a power circulating apparatus through worm gears which has provision for the accurate measurement of efficiency and temperature rise under variable load and speed. The theory underlying the heating and cooling of gearboxes is discussed, for gears running under continuous load and also under a repeated cycle of intermittent load. Temperature rise depends on the heat-dissipating capacity of the gearbox and the power losses within the box; heat-dissipating capacity is dealt with in relation to surface area of the box, speed of the gears, and artificial cooling by air fan; power losses are discussed under the headings of efficiency and oil drag losses. It is shown that gear speed and turbulence in the lubricant contribute considerably to heat-dissipating capacity, and that oil drag losses play an important part, particularly on large gears running at moderate or high speed. Cooling by air or other means is shown to result in an increase in power capacity (for a given allowable temperature rise) much more than in proportion to the increase in heat-dissipating capacity of the box, owing to a higher overall efficiency when transmitting heavier loads. Results of worm gear efficiency tests carried out in the past on the Daimler-Lanchester testing machine at the National Physical Laboratory on the author's design of worm gear, which gave the highest efficiency of any published tests carried out on this machine, are reconsidered in the light of recent work and it is contended that the National Physical Laboratory machine gives efficiency figures which are in general higher than the true efficiency.
Some Practical Applications of Rubber Dampers for the Suppression of Torsional Vibrations in Engine Systems
Authors: Zdanowich R. W. , Moyal J. E. 
Published: October 2007

The method of rubber damper design outlined in this paper has been developed owing to the breakdown on a number of occasions of the two-mass system method hitherto widely used. This new method, which is based on the study of the behaviour of the engine as a whole in conjunction with the damper, splits up the functioning of a damper into two parts, one conveniently called the detuning effect, and the other, the absorption effect. The first relies on the powerful tuning curve method, already described in the Proceedings, and the other is based on numerous painstaking trials and physical tests on rubber samples and on full-scale dampers. The method outlined shows that there is no rigid relationship between the frequencies of the engine and damper, and that the free end of the engine crankshaft is not the only place where a successful damper can be fitted. In addition to giving some particulars about physical and other properties of rubber, it also shows how to calculate the heat dissipated by dampers. Practical support for the theory is provided by accounts of vibration trials on three widely different types of engines with dampers fitted to them. In all cases, comparison of calculated and experimental amplitudes is given. The good agreement between the two cannot escape attention and shows that the method outlined can be used with confidence.
Recent Research in Metal Machining
Authors: Galloway D. F. 
Published: October 2007

Despite the introduction of comparatively new manufacturing processes such as powder metallurgy and plastics which are gradually assuming their true functions in industry, manipulation of metals by machining still occupies a place of major importance among methods of production and the efficiency with which machining operations are carried out continues to influence greatly the overall industrial efficiency of the country. Research provides a means of greatly accelerating progress toward the goal of efficient metal machining, and recent developments in other fields of science and industry now present opportunities of research and development in metal machining, incomparably greater than have hitherto been known. The progress recently made in the field of surface finish measurement which, for the first time, makes possible a rational investigation of finish machining operations, is just one example of newly acquired knowledge which can now be applied in solving the complex problems of metal machining.
On the Resistance Coefficient–Reynolds Number Relationship for Fluid Flow through a Bed of Granular Material
Authors: Rose H. E. 
Published: October 2007

The resistance coefficient–Reynolds number relationship for a bed of spherical particles, closely graded about a mean size, is considered and it is shown that this relationship correlates with that for a bed of non-spherical particles, provided a suitable allowance for particle shape is made. It is shown that for very large or very small values of the Reynolds number the co-ordinates of the resistance coefficient–Reynolds number curve fall closely about a mean line but for the transition-range the points suffer considerable scatter—probably due to the indeterminate nature of the flow in the pore channels for this range of the Reynolds number. Curves are given showing the frequency of occurrence of variations in the resistance coefficient, and an example of the practical application of these curves to a design problem is fully worked out. Curves relating the resistance coefficient to the Reynolds number for beds of particles of various degrees of angularity are put forward tentatively, these relationships being, as yet, not completely established.