Search

The problems confronting the chemist in control of water treatment for an industrial boiler plant are very complex and dictated to a great extent by the pattern of plant operation. An interesting field of study is presented, particularly where the plant is modern in design and very extensive in the service it provides. The author has concerned himself principally with the problems of water supply and treatment at Aylesford Mills, as these are very typical of those which occur in other large industrial undertakings. Details are given of the feed water treatment plant for the medium- and high-pressure boilers, consisting of primary sedimentation units using lime, ferrous sulphate, and alum as chemical additives, followed by a filtration stage. This section of the plant is followed by a dual system comprising three base-exchange softener units and a fully automatic demineralization plant. The interesting features of fully automatic regeneration of the demineralization plant are discussed, together with the author's experience in operating this plant. Emphasis is placed on high standards of feed water treatment and the principles of the system adopted. Sodium sulphite and tannin are added as chemical deoxidants on medium-pressure plant. Hydrazine, together with a neutralizing amine, are used on the high-pressure boiler installation. The author concludes the paper with comments on the subject of boiler corrosion.

The collection efficiency of nine types of filter papers for air sampling was determined for monodispersed polystyrene latex aerosols by using a forward light scattering photometer. The aerosols were 0.091, 0.198, 0.365, 0.500 and 1.099 mu m in dia., which flowed through a test filter paper at a face velocity from 4.2 to 200 cm/sec. Toyo No. 660, No. 60 and No. LP filter papers exhibited minimum efficiencies at the face velocity range between 10 and 80 cm/ sec, and in the particle size range between 0.1 and 0.5 mu m. The collection efficiencies of Toyo No. 5A and Whatman No. 41 filter papers were over 95% for all the particle sizes at a face velocity higher than 100 cm/sec. Toyo HE-40, HV- 70, Toyo GB-100 and Gelman E filter papers showed collection efficiencies higher than 99%. The theoretical filter efficiency based on single fiber filtering mechanisms and the effect of neighboring fiber interference on the collection efficiency are also discussed. (auth)

The frequency of occurrence of defects in electrical insulation can be shown to follow the Poisson law of probability. One of the more important defects in thin paper insulation is conducting particles. In this paper expressions are derived for the probable breakdown voltage as a function of conducting particle occurrence. It is shown by statistical evidence that large conducting particles exist in the insulating paper and bridge one or more layers of paper in the finished capacitor through chance reorientation caused by manufacturing processes and operation. The degree and frequency of reorientation of particles with a typical grade of paper is determined experimentally, and the probable insulation thickness and consequent voltage strength of various size capacitors is calculated. A method of determining the optimum voltage strength of this insulation is illustrated. It is concluded that conducting particles are a predominant factor in determining the voltage strength of present day capacitors and that one of the greatest opportunities for improvement lies in the reduction of the conducting particle content in the paper.

In dc cables the resistivity of the insulation is a very important parameter, as it determines the stress distribution and the power losses in the insulation. This paper gives the results of several tests on plane capacitors, from which the steady-state resistivity of four different kinds of paper and impregnants appear to be almost identical from this point of view. The transient behavior of one of the dielectrics is also shown, giving the current density as a function of time after the application of a direct voltage, for different temperatures and stresses.

THE HISTORY of the paper industry and the history of paper machine drives is a story of continued progress; progress in improved performance, increased reliability, and operator convenience.

STUDIES of the causes and mechanism of the failure of impregnated-paper insulation are commonly obscured by the burning due to the final complete breakdown. In a number of years of study of the more accessible properties of impregnated paper and their relation to stability and breakdown, constant attention has been given to the restriction of this burning and a nearer view of the beginnings of failure. Simple fuses and even rapid circuit breakers in the primary circuit of the testing transformer are of no avail. Some improvement is obtained by the use of a thyratron in the grounded lead of the sample with suitable connection to a rapid circuit breaker in the primary. But by far the best results, and indeed very complete success, have been reached by a method for detecting the first occurrence of gaseous ionization within the test specimen. This method is a development of the pioneer work of Paine1 and the subsequent applications of Arman and Starr and of Whitehead and Shaw,2 using resonance methods for following the oscillations which arise in the ionization of gas spaces in the insulation wall. New features which have been added are increased sensitivity, improved balancing of the Schering bridge for the frequency of maximum oscillations, the use of greater amplification, and a sensitive recording instrument for registering the first occurrence of internal ionization. The complete setup, as described in this paper, is called the “ionization recorder.” With this instrument it is possible to detect the beginnings of failure in a completely impregnated specimen initially free of gas spaces or voids, often to within one layer of the impregnated structure, and also to follow its growth, with interruption at any desired stage on the way to complete breakdown. So far, the instrument has been applied only to the study of the influence of paper density on dielectric strength and stability, and the comparative behavior of two types of paper and two types of oil. From the results it will be seen that a very intimate picture of breakdown and its causes is presented.

A method has been developed for economically manufacturing insulated wire for telephone exchange area cable by making the paper on the wire. Further, this method has made it possible to increase the number of wires in a full sized cable by 175% over the number in use in 1914. Developments now under way indicate that suitable insulation can be made to replace certain textiles in some classes of wire and that the use of this process may therefore be still further extended in the not so distant future.

The employment of radio-frequencies for chemical analysis was suggested and commenced by the author in 1936. Brief mention is made of the gradual development of the “conductrimetric tube” with references to papers by him and other workers, and a new application of external electrodes and displacement currents to chromatography is presented. A circuit diagram is given in which both rectification and amplification are achieved by the use of a “Transistor”.

Within the last DECADE digital computation has evolved from the scientific computer with simple input-output devices to the present-day-electronic data processors with their myriad of peripheral devices. This development is continuing with the addition of facilities to provide intercommunication between the central processor and remote points. Such a device has been developed by Honeywell for use with the DATA matic 1000 System.

The full text of this article is in Arabic - see PDF below. doi: 10.3329/iiucs.v3i0.2677 IIUC STUDIES Vol. - 3, December 2006 (p 91-104)

Application of a recently developed method whereby it is possible virtually to see the voids in the layer structure of high voltage cable insulation shows most such insulation to be mechanically irregular. Lack of mechanical uniformity in the cable as manufactured is responsible for much of the ionization after the load cycle, and probably to a great extent for ionization break-down. Application of the method and of supplementary methods should lead to better load cycle stability, improved installation practice, and ultimately to reduced insulation thicknesses.

Research on the dielectric strength of high-voltage cables can be very conveniently carried out on "models". Either plate or cylindrical capacitors can be used for this purpose. This paper reports the results of many tests both at power frequency and at impulse, which have the purpose of investigating the separate and combined influence of a series of different factors affecting the dielectric strength of a fully impregnated paper insulation as used in high-voltage cables. The main factors investigated are the following: Paper impermeability, Paper density, Paper thickness, Oil viscosity, Oil pressure, Electrode surface shape, Electrode surface nature, Butt-space thickness, Butt-space position with respect to electrodes. Butt-space relative position. The paper ends with a comparison of results obtained on models and on actual oil-filled cables, which show a good agreement if certain assumptions are taken into consideration.

Late in the summer of 1967 Southland Paper Mills, Inc. placed in operation a 52,000-kw combined cycle power plant. The plant utilizes two 13,550-kw gas turbines and one 25,000-kw single automatic extraction condensing steam turbine. The power plant furnishes the total power requirements for their new Sheldon mill. This paper presents background data on the mill and describes the power plant in some detail. Flow diagrams are presented and reviewed. Features of the generating equipment and the steam generators are described. Switchgear and load coordination is discussed. The operation and reliability of the plant to date are summarized and the combined cycle in terms of paper mill requirements is evaluated.Copyright © 1969 by ASME

The Paper-Tape-to-Magnetic-Tape Converter consists of two racks of electronic equipment whose function is to transcribe seven-channel digital code on punched paper tape to seven-digital code on magnetic tape in a form compatible with the input requirements of the IBM 704 and 709 computers. Recording is accomplished by electronically controlling the "read" and "stop" modes of the paper tape reader while the magnetic tape continuously advances. The converter also checks for certain types of error in the structure of the coded information on the paper tape and indicates their presence. The encoded magnetic tape is used as the information input to a properly programmed IBM computer. (auth)

Publisher Summary Nucleic acid components on paper chromatograms are photographed by making a contact print by filtered ultraviolet light onto sensitized paper through the dried paper chromatograms. In the procedure, the source of ultraviolet light is a Hanovia Homesun lamp, a 450-watt, 200-volt, mercury arc lamp. This is used in conjunction with a specially constructed filter. Various sensitized papers used for making contact copies of printed pages are suitable for the present purpose, for example, Kodagraph Contact Standard. Time of exposure and distance of paper from the light source are determined with known standards. For making the prints, it is quite satisfactory to pin the chromatogram paper over the photographic paper on a planoconvex wooden surface. A piece of plywood is fastened to a board with a small strip of wood under the center to bow the plywood out a little. After development, the paper is fixed and washed in the usual way.

Insulation paper is primarily used in electric motors as slot cells, coil separators and phase insulation in integral horsepower equipment. The slot cell being defined as the basic ground insulation that provides mechanical and dielectric barriers from the magnet wire to the stator core. This definition emphasizes that the insulation paper forming the slot cell is mainly ground insulation.

The paper gives the history of the conception and design details of a mass-produced four-cylinder 803 cm3 engine, its redesign to 948 cm3 and the design of a twin-carburettor version. Finally a further redesign to increase the capacity to 1147 cm3 for both single- and twin-carburettor versions. An initial appraisal was made of the type of unit required to power a small family saloon car. Engine performance requirements were established from a performance curve of the vehicle obtained from frontal area aerodynamic coefficient, estimated weight, etc. The configuration of the unit was fully investigated, the number and disposition of the cylinders, type of cooling, position of valves and type of valve gear were all explored, bearing in mind technical requirements, cost and ease of production and production plant requirements. Having decided upon a four-cylinder in-line liquid-cooled unit, a detailed description is given of the reasons for the design configuration of the major components and the disposition of the ancillary equipment. The need to extend the range of models of this vehicle brought about the first increase in capacity to 948 cm3 and design modifications are enumerated. A twin-carburettor version was a further requirement and design and development details are discussed. With the introduction of a completely new design of motor car using this power unit, the road holding and general handling characteristics of the vehicle were so outstanding that improved engine performance became a necessity to match the above qualities. The methods of increasing performance are discussed and the reasons given for the necessity to increase capacity. In view of already established transfer machinery for all major components, the minimum of change was essential and a history of the design and development of the unit is given. It is shown that careful study of existing equipment is vitally necessary when making extensive design changes. First designs made the minimum of change and only when test work showed shortcomings were further changes made. A series of designs and tests finally achieved a sound design giving excellent results from extended tests. This process established that all the modifications were vitally necessary to achieve the performance and reliability necessary for the engine to have a further period of production and enable progressive development to be successful.

Based on measurements, the strength of synthetic oil impregnated capacitor paper (Askarel) to dc and ac voltage 1.2/50-?s voltage surges and switching surges of various wavefront duration are discussed. The results of measurements are compared with the performance figures of mineral oil impregnated capacitor paper. The diminishing effect of the number of lightning and switching surges and their amplitude upon electric strength and of initial voltage partial discharge is investigated.

The second paper assesses the overall performance characteristics of the differential compound engine (d.c.e.) first reported in (21), designed to constitute an integrated engine-transmission system providing high unit output, combined with outstanding torque characteristics for traction applications. Experimental results, for both equilibrium conditions and transient response are presented for the original two-stroke c.i. version of the laboratory unit, incorporating the Rootes TS 3 opposed piston engine. Theoretical predictions both for this version, and the later four-stroke version, using the Perkins 6·354 engine, based on the generalized computer approach of the first paper, are also presented. The unit is then critically compared with existing or prospective traction prime movers using the following criteria. (1) Fuel economy. (2) Torque characteristics. (3) Noise and emission. (4) Unit specific weight and bulk. Finally, a projected automotive unit of approximately 2 hp shaft output is described with illustrations to show the potential of the d.c.e. as an alternative engine-transmission system for heavy trucks and off-highway vehicles.

An automatically recording densitometer is described depending on the use of a photomultiplier operated at constant anode current. The application of this instrument to evaluation of electrophoresis data from filter paper strips is discussed. Some advantages of the circuit are outlined.

FOR a number of years the standard low-tension direct-current feeder cable in Chicago was 1,000,-000-cir. mil two-conductor concentric paper-insulated cable with three pressure wires laid up with the outer conductor. Apparently there has been the greatest tendency to overload this particular size of cable more than any other as, with both single and concentric cables in service, it was difficult to make a proper distinction between the carrying capacity of the two kinds of cables. About ten years ago we had two cases in which the cables of this kind were called upon to carry loads somewhat larger than had been customary, and steadily throughout the day instead of a short peak in the evening. The two customers in these cases, in different portions of the city, were both manufacturing customers with an eight-hour load, and on account of some increase in business they increased their load on short notice when no cable was available for another feeder to their premises. In each case, the cable has to be ordered from the factory so that this unusual load was carried by these cables for some three or four months. In the first case of this kind we were so disturbed about the temperature that we made a rather extended series of temperature measurements, using one of the pressure wires imbedded in the outer conductor as a resistance, and determining the temperature by the rise in resistance. This, of course, would give us the temperature of the outer conductor which would be probably 8 or 10 deg. lower than the inner conductor. The temperature measured in this manner was slightly above 100 deg. cent., and as there was some doubt regarding the accuracy of the determination made in this manner, it was checked by cutting a small hole in the lead sheath of the cable and in the outer insulation, and measuring the temperature of the outer copper with a thermometer. The temperature taken in this way checked very closely with the temperature as determined by the rise in resistance of one of the pressure wires. The insulation removed in this manner was carefully preserved and compared with the insulation in a piece of new cable, and it was impossible, by careful examination, to discover any appreciable difference.

This paper contains the results, plotted non-dimensionally, of extensive tests carried out on a 1–625-in diameter grinding machine spindle lubricated hydrostatically. The horizontal spindle is directly coupled to a variable-speed motor at one end and loaded vertically at the other. The spindle is not constrained to rotate at arbitrary eccentricity values, but is able to seek an equilibrium position depending upon oil flow and rotational speed. The attitude, oil film thickness, and eccentricity are measured by mutually, perpendicular capacitance probes arranged in the bearing housing. The results indicate considerably decreasing load-carrying capacity as the rotational speed increases, because the hydrodynamic effect tends to centralize the shaft in the bearing housing, thus nullifying the hydrostatic effect. Paradoxically the same effect causes an increase in oil film stiffness as it is generally defined. A summary of earlier work is included, notably that of Raimondi and Boyd who considered bearings of fixed eccentricity, and the paper also presents a theoretical analysis based on the pressure- and velocity-induced circumferential flow theories.

The paper reviews the present state of knowledge and design techniques and attempts to provide a physical appreciation of the characteristics of bearing performance. The work which has been carried out recently in the United Kingdom, the United States, The Netherlands and Germany is examined and the paper attempts to relate this to experimental results and the practical engine. The possible relationships of components within the engine which affect the conditions of operation and parameters which could lead to improvement of these conditions are suggested and examined, and the possibilities of future work in exploring this area are indicated.

This paper presents an outline of the power and energy requirements of a human elbow and gives a discussion on the means by which these requirements can be met. Reasons are given for the choice of a system using batteries for energy storage and direct electric drive by a motor and gearbox. The gearbox is of an unusual type, using ‘harmonic drive’ elements, which permit the motor to be installed transversally at the elbow. The gear reduction unit is described in detail. The paper also discusses the problems inherent in controlling a motor with large stall current in such a way that most efficient use is made of the energy stored in the battery, and two control circuits are described which meet the requirements.

Metallized paper capacitors are being introduced into telephone apparatus wherever size is of prime importance. It is shown that low-voltage metallized paper capacitors with about half the volume of a foil-paper capacitor of conventional design have about the same characteristics as the latter. Performance data are discussed which indicate that such capacitors will give long service when used within their voltage rating and when well-protected against moisture. It is pointed out that this type of capacitor should be used within its voltage rating if sparking with its attendant circuit noise is to be avoided. When sparking does occur due to abnormal voltage conditions no permanent damage results.

For many years shellac or synthetic-resin-coated paper has been used in winding condenser bushings. Two years ago work on the development of oil-impregnated-paper condenser bushings was undertaken. When a shortage of shellac was imminent because of the war, effort to complete the development was greatly increased, resulting in its being completed well ahead of the date originally set. Manufacturing processes and impregnating treatments were developed and bushings built and tested. The processes and treatments are described, and the data obtained from tests on representative bushings are given. Complete interchangeability for transformer and circuit-breaker bushings has been obtained for current apparatus designs in the voltage ratings in which the bushings are produced. To a large extent, the new bushings are also interchangeable with bushings of older design in the same voltage rating. The entire insulating portion of the bushing is enclosed in porcelain and metal and this enables the bushing to be held in storage without special provisions for keeping it dry. The oil-impregnated-paper condenser bushings, built for voltage ratings 92 kv to 230 kv, are susceptible to careful control of quality in the processing operations. Exceptionally consistent performance and high dielectric strength are obtained. Consistently low power-factor readings on both hot and cold bushings were obtained. Radio-influence voltage measurements were below proposed standards.

The objects of this paper are to demonstrate the use of the method described in Paper 6 and to give an indication of the effect of design parameters on the performance of a dynamically loaded bearing. An investigation into the main and big-end bearings of a diesel engine of modern design is described. The performance of a bearing is gauged by obtaining: (a) the minimum oil film thickness, (6) the maximum pressure developed within the oil, (c) the maximum load/projected area, and ( d) the bulk oil temperature rise. The influence of the engine design upon the big-end bearing performance for the particular engine under consideration is found by investigating the effects of the following parameters: ( a) bearing length-diameter ratio, (6) removal of centre-circumferential groove, ( c) inlet temperature, ( d) bearing clearance, and ( e) loading diagram. This last parameter is varied by changing in turn the piston mass, the connecting-rod mass, and the position of the connecting-rod centre of gravity. Finally, the effect upon the main bearing performance of various balance weight configurations is demonstrated. The usual assumption is made to obtain the main bearing loads: that loads imposed by a crank throw are equally distributed between neighbouring main bearings. General conclusions are made regarding the relative influence of certain bearing-design parameters upon the bearing performance.

The paper deals with the story of the engines intended for the smaller Fiat cars, starting with the ‘500’ model produced in 1936: all engines with displacements in the neighbourhood of 500 cm3. With small cars, especially of the utility class, the adaptability of the piston engine to a variety of design and space requirements is used to best advantage. The size, weight and displacement must blend with the design of the car as a whole; in turn, the design must feature the highest degree of simplicity compatible with the qualities required. It is, therefore, important for the engine of utility cars to be designed as a function of the general architecture of the vehicle. At Fiat, after a period in which economical cars of conventional design were produced, work was started along this line with the ‘500’ (Topolino) model in 1933–1934. The paper illustrates the design of this model and describes the reasons behind some of its engineering details, as well as the subsequent developments which led to the final solution. Also outlined are the more important designs of experimental engines studied as substitutes for the ‘500’ model: a transversal four-cylinder engine, with overhead camshaft, built in 1945, for a front-wheel drive prototype; an air-cooled, two-cylinder in-line engine, mounted transversally, for a rear-wheel drive prototype; an opposed two-cylinder engine, with longitudinal axis, in replacement of the previous unit; a two-cylinder in-line engine with longitudinal axis, finally chosen for the ‘New 500’ model introduced in May 1957. Also described are the further developments of the latter engine for the version with horizontally arranged cylinders suitable for underfloor application. The paper highlights the more interesting aspects regarding both the design and the experiments made and explains the principal reasons leading to the choice of given solutions and to the modifications which followed.

This paper is about the applications of an epoxy-impregnated paper insulation to ultra-high-voltage systems. An epoxy-impregnated paper insulation is a resin-rich void-free structure, and therefore has extremely superior voltage withstand characteristics. It also has outstanding resistances to thermal cycle and mechanical vibration. Consequently, such insulation systems can be applied easily to condenser bushings. From the standpoint of the production facilities, techniques, and economical considerations, in items with an overall length of more than 3 m, "prefab"-type condenser bushings, consisting of several condenser cores, are desirable. In cases when two-unit condenser cores are assembled leaving a simple conical-shaped gap between them, it is extremely effective to adopt a "potential-expanding"-type gap designed so that the equipotential surface in the gap will be in the vertical position to the cone surfaces as far as possible. The prefab-type condenser bushing of the 500-kV class was experimentally manufactured using this arrangement; it displayed all the desired properties. This paper also describes the other examples of applications of epoxy impregnated paper insulation: CT bushings and pulse transformers in the magnetic firing system for high-voltage dcconverters using thyristors, and draw-out-type condenser bushing for disconnecting devices used in the compact-type substation.

The paper states why air conditioning is necessary particularly in office blocks in cities, where noise, dust and heat from office machinery together with solar heat gain through large glass areas are experienced. The relatively small addition to building costs in incorporating air conditioning is shown. The distinction between air handling, ventilation and air conditioning is defined and the constituent parts of a complete air-conditioning unit are enumerated. The requirements in terms of fresh air needs, temperature and relative humidity for the normal applications of air-conditioning units are tabulated. A comparison of the main categories of air-conditioning equipment is made, dealing with high and low velocity as well as special laboratory type units. A typical performance specification is also given together with data sheets for collecting the necessary design data and cost comparisons. The paper concludes with a discussion on system design incorporating factory-made equipment and literature references.

ROY V. SCOTT: Partly because of what one speaker yesterday termed inertia and partly because I did not receive Harold Benjamin's manuscript until Friday, I shall concentrate the bulk of my remarks on our first paper. I hope that our second discussant will give the Benjamin paper the treatment it deserves. In passing, however, I can not refrain from saying that, while students could accept his main thesis, his broad generalizations and his stages of national development cast very little light on the evolution of agricultural education in the United States. Mary Jean Bowman, in her paper, has undertaken a task that should intrigue all students of education history and of economic growth. If I may paraphrase her, she has attempted to show the kinds and quantities of human resources created by the land-grant schools, determine the methods used, and assess their contributions. This is an immodest task, she tells us, and one would be inclined to agree. In examining the subject, certain facts stand out. Clearly the land-grant colleges were both a product of and a force in the new concept of education for the masses. In fact as well as in theory their doors were thrown open not only to the sons of the wealthy but also to the sons of the common farmer and the manual laborer. Perry G. Holden, later head of International Harvester's extension department, tells us that when he came off a backwoods farm to attend Michigan Agricultural College, he was a complete stranger to such luxuries as white shirts. Similarly, the colleges stemmed from and contributed to the idea that education should have a utilitarian value. One might question whether labor in the fields and the barns at eight cents an hour would convince the victim of the usefulness of the education he was getting, but there can be no doubt that "practical" was a key word in the vocabularies of early land-grant college planners and administrators. In conjunction with the non-land-grant state universities, the new schools played a major role in opening higher education to women, thereby providing the nation with a new and expanding labor source. Also, because the new institutions lacked students, early administrators had to manufacture them. As a part of this endeavor, they stimulated the development of the secondary school system. Finally, while it is a mistake to say that the landgrant colleges were the predominant force in the establishment of extension, they did become after I9I4 the centers of the greatest adult education system in the world, presumably reaching directly or indirectly a majority of the farmers and their wives in the United States.

LACK of factual information relative to the permissible pulling loads to which solid-type impregnated-paper lead-sheath power cable might be subjected by means of woven-wire pulling grips without damage to the sheath prompted the Insulated Power Cable Engineers Association to consider the subject and resulted in the laboratory tests described in this paper.

The paper is set in a background of boiler commissioning for customers in power generating, industrial, marine, petro-chemical and oil-refining companies in Britain and overseas. Some of the problems encountered during the commissioning of a diversity of units employing solid fuel, oil fuels, naphtha, gas fuel firing, either singly or in combination, are discussed, and actual case histories detailed. The paper embraces difficulties experienced with the ignition of fuels, the control of flame shape, air distribution to burners, layout of fuel supply lines, safety circuits, and the necessity for close collaboration between the customer and the designer during the tender and contract stages, in order to avoid loss of availability, resulting from delays in commissioning or subsequent damage to equipment.

This paper describes two different computer programs for the calculation of rolling bearing applications in an automotive driveline. The first program gives the effect of bearing preload or internal clearance on bearing deflections and nominal lives in bearing applications with taper roller bearings. As an example, the paper deals with a front hub bearing arrangement with two taper roller bearings used in a front wheel driven car, and also with a pinion of a final drive unit and a gearbox mainshaft incorporating two taper and one cylindrical roller bearing. The second program is used to determine the influence of misalignment and shaft deflection on the load and life of a deep groove ball bearing. To illustrate this effect the layshaft of an automotive gearbox is studied.

This paper describes the various types of centrifugal compressor used in process plants, and continues to discuss the more important components of these compressors and particular design features which are required to overcome some difficult operational problems. Items of particular interest include a discussion on the latest form of compressor rotor construction, the techniques required for balancing a rotor at full speed, and a detailed analysis of shaft gas seals and problems that can arise with gas seals under certain operating conditions. The paper also describes such special subjects related to process plant compressors as compressor selection and design by utilization of computers, methods of reducing time to produce compressor orders by discrete stockholdings; types of driver and shaft couplings used for these machines, and test facilities employed for centrifugal compressors which can be utilized to reduce commissioning periods at site.

In 1924 two papers were presented before the A. I.E. E. on Turbo Alternator Ventilation. In one of the papers tests on two models for two methods of ventilation were described, and data from the tests were given. The other paper contained a mathematical treatment for one system of ventilation, which was based upon the data obtained from the tests. It was recognized that the tests were not sufficiently accurate to evaluate the loss coefficients, nor was it possible to obtain data on the distribution of volumes for the intake vents. For that system, (see Fig. 1), it was found that the influence of rotation upon total volumes and their distribution could be neglected; consequently the investigation could be continued on stationary models. Those tests, the methods of determining the losses and the equations derived therefrom are given in this paper. Since the effect of rotation could be neglected, the test could be reduced to a model which represented only one axial row of vent ducts. On this model the stator vent ducts were imitated by square brass tubes with a plaster of paris restriction cast in one end to imitate the vent duct restriction so that the pressure drop obtained for either direction of flow was approximately the same as in a stator vent. A long steel channel or duct represented the section of the air-gap. Some of these brass tubes, representing intake vents, lead from a large sheet metal box to the gap channel. Other tubes, representing discharge vents, lead from the gap channel to the atmosphere. The gap channels could be inter-changed readily to represent various sizes of air-gaps. Any desired number of intake and discharge tubes could be used so as to represent any desired layout of the machine. The volumes in individual intake tubes were measured by reading on a manometer the drop in pressure from the intake chamber to a point a little ways down the tube. For the discharge tubes small impact tubes were employed. Each tube was carefully calibrated before making any other tests; a thermal volume meter was used for calibrating an orifice, and the orifice was used for the lube calibrations. Various difficulties arose, and the means of overcoming them are given. Tests were made with a group of intake vents, and the losses were separated into (1) those in the tubes; (2) those accompanying a right angle turn; (3) those due to a stream of one velocity impinging upon a stream of another velocity; (4) those due to sudden increase in velocity; (5) those due to surface frictions. Similar tests on the discharge side showed that the losses there could be separated into (1) those in the tubes; (2) those accompanying a right angle turn; (3) those due to sudden decrease in velocity; (4) those due to surface friction. The losses were put, for the most part, into comparatively simple expressions. They were then combined in order to obtain final solutions. There was no difficulty on the intake side in obtaining a differential equation which admitted of ready integration. On the discharge side, however, it was necessary to use approximations. With the aid of the final equations the total volumes and their distribution can be calculated for a given pressure drop. One difficulty is that the equations include trigonometric and hyperbolic functions of quantities involving the distance between the point where the gap velocity is maximum to the points where the gap velocity is zero. The latter point, called the “balance point” is not known, and a simultaneous solution of the transcendental equations needed for its determination, is impossible. Suggestions for a direct simple approximate solution are given, which may be followed by trial and error methods. In most of the applications, only one or two trials were required. The equations were checked for accuracy by comparison with tests made on the tubes, on the turbo model of 1922 and 1923, and with those on an actual machine. The agreement in total volumes was very close, and is considered to be quite good for distribution also.

A versatile automatic scanner for paper strips which records directly optical density or radioactivity is built around a servo type recorder (Brown). Interference filters provide a narrow band light source. For scanning in the visible or ultraviolet where monochromatic light is desired the monochromator of a Beckman model DU spectrophotometer replaces the filters. The instrument incorporates positive synchronization of strip and recording paper, sequential scanning of strips to provide an optical density curve followed by superposition of the integral of this curve. Areas are easily calculated without the need for planimetry. The slits of varying size are interchangeable and are designed for either optical or radioactive scanning. For medium levels of activity a Geiger‐Muller tube is interchangeable with the photocell, while for low activities, optical scanning of autoradiographs may be performed.

This paper deals with power take-off systems, but not with design details of the units being driven, or of the take-off mechanisms. Shaft stresses, gear teeth, and bearing selection are covered in existing literature, and handbooks issued by various authorities give the established standards for coupling and aperture dimensions. The paper gives information about the least well-known systems, and some of the major problems are highlighted.

This paper reviews the installation of automatic transmissions into vehicles, and the matching calibration of the transmission and converters to various types of engines and vehicles. Bench and field acceptance testing, with some reference to transmission manufacturers' approval of fluid and materials, are also discussed, and unorthodox automatic transmissions such as transaxle in-line and transverse, are reviewed. The paper finally examines volume production techniques of today's automatic transmissions and presents some remarks on future trends and requirements.

1. In the paper recently communicated to this Society, Dr. Duffield has described a promising method of determining gravity at sea, but a somewhat fuller discussion on the theoretical side is required before an opinion of its capabilities and limitations can be formed. For this purpose it is more especially necessary to investigate the effects of the forced vibrations which may be imposed on the mercury in the apparatus by the vertical acceleration of the ship. 2. The problem of determining the period of free oscillation in a barometer tube is very simple, but in the present case three tubes are connected with each other, and at least two of the tubes are not of uniform section, but contain a portion with a narrow bore introduced to damp the oscillations.

Performance of capacitors on accelerated life test may vary over a wide range depending upon the capacitor paper used. Indeed, at present a life test appears to be the only practical means for evaluating capacitor paper, since, within the limits observed in commercial material, the chemical and physical tests usually made do not correlate with life. Lack of correlation is ascribed to obscure physical factors which have not yet been identified. Generally, several weeks are required to evaluate a paper by life tests of the usual severity. Unfortunately, the duration of these tests is too long for quality control of paper. The desire for a life test which requires no more than a day or two for evaluation led to the development of a rapid dc test. The philosophy of rapid life testing is based upon the experimental evidence that the process of deterioration under selected temperature and voltage conditions is principally of a chemical nature, and also upon the well-known fact that rates of chemical reaction increase exponentially with temperature. Life tests on two-layer capacitors conducted at 130°C provide an acceleration in deterioration many fold more than that obtained in the lower-temperature life tests, and correlate well with these tests.

Presented in this paper is an analytical method of producing design curves for tilting pad gas journal bearings, with dimensionless parameters chosen in such a way that a single set of curves may be used for any size of bearing with any length to diameter ratio. An analytical solution to the compressible Reynolds equation, based on the linearization by Ausman, is presented in detail. Comparisons are made between the analytical results, numerical results, and experimental findings on the author's rig at Southampton University. Included in the paper is a sample design curve, together with equations for constructing additional curves. The author concludes by briefly outlining his proposed extension of this work.