bluuebunny/crossref_metadata_2025 huggingface dataset:
Contribution to the Theory of Oil Whip
Authors: Poritsky H.
Published: July 2022

Oil whip of a rotor consists in a whipping or whirling motion of the rotor shaft, of frequency essentially equal to the critical frequency of the rotor; it occurs at rotor speeds roughly exceeding double the critical speed. In the paper it is shown that an explanation of oil-whip phenomena, at least for small eccentricities, can be obtained from the equations of hydrodynamic forces and the dynamical equations of motion, provided that the hydrodynamic-force expressions be modified to delete from the oil forces the hitherto included contributions from the regions of negative pressure.
Contributions to Hydraulic Control: 3—Pressure-Flow Relationships for 4-Way Valves
Authors: Blackburn J. F.
Published: July 2022

The characteristics of several types of 4-way flow-control valves are derived without making linearizing assumptions. These characteristics are plotted as load flow versus load pressure, in a manner analogous to the plate characteristics of a vacuum tube. Several differential coefficients are derived and tabulated, and the valves are compared from the standpoint of linearity, sensitivity, power output, and losses.
The Effects of Cold-Drawing, Microstructure, and Thermal Treatments on the Machinability and Mechanical Properties of Carbon and Alloy Steel
Authors: Dreves Ford E.
Published: July 2022

The purpose of this paper is to describe the role of the cold-finished steel mill in the field of metal cutting. With constant advances in machining techniques, the mill is looked upon to supply more closely controlled material to meet the demands of the production engineers and machinists. Production engineers are now more conscious of metal-cutting economics than ever before. They are confronted with innumerable factors that affect machinability. However, they desire more knowledge of the tangible factors such as the material, and how it will affect their production including secondary operations such as cold crimping, heat-treating, and so forth. Where cold-finished steel bars are concerned, there are several ways such bars can be produced, one of which may be the most suited for a particular application. The cold-finishing operations are described briefly. The effects of cold-drawing on the machinability and mechanical properties of some common grades of steel are explained. Microstructure plays an important role in the machining of all grades of steel. Its effect on the machinability of plain-carbon grades and medium-carbon constructional alloy grades is discussed, along with the common thermal treatments employed to control it. The advantages of stress-relieving for certain applications are mentioned.
Temperature and Gas-Analysis Surveys in the Combustion Zone of a Gas-Fired Gas-Turbine Combustor
Authors: Rieke K. L.
Published: July 2022

In a gas-turbine combustor, optimum conditions with respect to fuel, mixing of fuel and oxidant, and piloting the combustion must be accomplished under extreme space limitations and over a wide range of fuel-air ratios. To achieve such a design, data such as given in the paper as to the admission of the fuel and oxidant and their mixing and reacting are desirable.
The Mechanism of Disintegration of Liquid Sheets
Authors: York J. L. , Stubbs H. E. , Tek M. R.
Published: July 2022

The disintegration of a plane sheet of liquid of finite thickness, moving tangentially relative to a surrounding fluid, is subjected to mathematical and experimental analysis. Instability and wave formation at the interface are established as the major factors in the breakup of the sheet of liquid into drops. An equation is derived relating four significant dimensionless groups, and a graphical presentation of the quantitative relationship among these groups is included. The force balance between the interfacial tension and aerodynamic forces is the basic concept, and the criteria for stability and instability are determined from it. It is possible to predict the conditions for maximum instability, and therefore for the most rapid disintegration of the sheet. Short-exposure photographs of the actual disintegration of the sheet are included to support the analysis, and a prediction of drop size in the spray compares favorably with measurements by other methods.
European Practice With Sulzer Monotube Steam Generators
Authors: Gastpar Jacques
Published: July 2022

Most important basic assumptions and considerations have led to the choice of systems and designs adopted in a number of typical monotube installations, for which interesting operating experiences have been obtained. Since the advantages of once-through boilers are more pronounced for highest working pressures and temperatures, the paper discusses application to present and future industrial as well as public-utility purposes.
Approaching the Control Problem of the Automatic Chemical or Petroleum Plant
Authors: Long M. V. , Holzmann E. G.
Published: July 2022

In an effort to gain a more thorough understanding and to rationalize the design of process-control systems in the chemical and petroleum industries, a complementary program of field tests and analytical studies is being undertaken. The paper presents two practical examples of the implementation of this program. One of these examples is the operational analysis of a continuous catalytic-reaction process and its associated control system. The other example refers to field tests on a turbine speed-control system. Presentation of the results is followed by a discussion of some of the problems encountered in the experimental determination of process characteristics in the field. A technique based on correlation analysis is suggested as a possible solution to certain of these difficulties.

The paper cites some of the outstanding benefits to be expected from computer control. The computer controller in the chemical and petroleum plant of the future is to be regarded as an aid to, rather than a substitute for, the human operator. Practical engineering difficulties, manpower problems, and above all, questions of economic feasibility, point to a compromise solution between fully automatic and manually assisted control as the goal toward which the industry will be working in the next few years.
Requirements for Large Light-Metal Forgings and Extrusions in the Aircraft Industry
Authors: Papen G. W.
Published: July 2022

This paper discusses the aircraft-industry requirements for large forgings and extrusions and supports these requirements by analyzing the effect of the trend in performance on aircraft structure, function, and production. The paper confirms that large integral structural components satisfy these trends better than a continuation of conventional “bits and pieces” structure. It further concludes that large forgings and extrusions are the most economical methods to produce an integral-type structure. In addition, detail requirements of large forgings and extrusions relative to physical properties, tolerances, and refinements are presented. Statistical studies are given to indicate the high potential use of large forgings and extrusions.
Design and Construction of Large Forging and Extrusion Presses for Light Metals
Authors: Stone M. D.
Published: July 2022

The author, whose company is engaged in building 110,000 capacity tons of large forging and extrusion presses for light metals, gives a comprehensive review of all aspects of the current heavy-press program. An Appendix is included which gives basic mathematical data pertaining to forging and extrusion.
Effect of Absorbed Water on Physical Properties of Phenolic Plastics
Authors: Quackenbos H. M. , Hill J. M.
Published: July 2022

The absorption of water by phenolic plastics obeys Fick’s law and can be described completely by a saturation constant, a diffusion constant, and a simple relation between diffusion constant and temperature. Two important consequences of water absorption are that mechanical properties change and all dimensions expand, the magnitude of each seeming to remain roughly constant for each per cent of water absorbed. In practice, expansion may give rise to undue warping and high stresses (or even failure) and is directly connected with dimensional stability. It is shown how these effects may be analyzed rationally by using the coefficient of expansion and the constants describing absorption.
Stress Conditions in Flanged Joints for Low-Pressure Service
Authors: Waters E. O. , Williams F. S. G.
Published: July 2022

The test program reported in this paper was undertaken to establish the critical levels of strain, stress, and deflection that exist in flanged joints having dimensions typical of those used with steel pipe lines in potable water-supply systems. Such water systems generally operate at low or moderate pressure levels. The investigation was limited to flanges of the low-hub and plain-ring types attached to the pipe by fillet welds. The design of flanged joints and connections for high-pressure and high-temperature connections has been well explored and reduced to standard procedures. Conditions that exist in water-supply service are generally more favorable than those encountered in similar industrial piping or in pressure-vessel service. Therefore it was hoped that the test program might shed light on possible modifications to the established design approach that prevails in the general field of design.
A New Method for Determining the Static Temperature of High-Velocity Gas Streams
Authors: Clark J. A. , Rohsenow W. M.
Published: July 2022

The general problem of measuring the static temperature of gases flowing at high and low temperatures and at low and high velocities is reviewed. Thermodynamic methods are discussed and a new method is presented with experimental results. This proposed temperature-measuring method has several important and desirable features: (a) The calculated static temperature is practically independent of gas composition in so far as composition is characterized by the specific-heat ratio k; (b) like the thermocouple, the temperature determined by this method is a “point” value, not a mean value at the flow cross section where the measurements are made; (c) unlike the thermocouple, the method improves in accuracy as both the gas temperature and velocity are increased; and (d) the instrument required is relatively simple to build, is not subject to the effects of corrosion, and is extremely rugged when installed. The instrument requires no special handling and can be installed conveniently and easily in ducts of any shape or in a stream of unconfined gas.
An Instantaneous and Continuous Sodium-Line Reversal Pyrometer
Authors: El Wakil M. M. , Myers P. S. , Uyehara O. A.
Published: July 2022

The theory, development, and calibration of an electro-optical sodium-line reversal pyrometer are given. This pyrometer instantaneously and continuously determines and indicates the black-body temperature of a non-luminous flame made luminous at the sodium wave length by the addition of sodium. Typical data obtained on a spark-ignition engine are presented and compared with data obtained by previous investigators. A correlation of these data with combustion-chamber design indicates the possible existence of a high temperature in the flame front.
A New High-Yield-Strength Alloy Steel for Welded Structures
Authors: Bibber L. C. , Hodge J. M. , Altman R. C. , Doty W. D.
Published: July 2022

This paper concerns a new kind of steel, its development, its metallurgical characteristics, its welding and gas-cutting characteristics, its low-temperature toughness, its applications, and its engineering potentialities. This steel was developed by the United States Steel Company to offer to industry a plate steel having a unique combination of properties, such as a far higher strength than has hitherto been available, superior toughness, and good weldability. As will be evident from the test results which will be described in detail, these rather formidable goals have been achieved. This new USS “Carilloy” steel has been designated “T-1.” It is characterized by yield-strength levels of 100,000 psi and above. At these high strengths it retains its toughness to much lower temperatures than ordinary structural steels. In addition, welds which develop the full strength of the base metal can be made in T-1 steel without preheating or postheating.
Line-Reversal Techniques in the Determination of Temperature of Gun Flash or Other Rapid Transient Phenomena
Authors: Agnew J. T.
Published: July 2022

A modification of the conventional line-reversal technique has been utilized for the determination of the temperature of an exploding gas mixture. A monochromator, employing either a photomultiplier or lead-sulphide photoconductive cell as the detector, has been used to isolate characteristic sodium, potassium, and water-vapor radiation at 0.589, 0.77, and 0.942 microns, respectively. Peak temperature values were determined for the external gaseous explosion commonly known as secondary flash, associated with the firing of a gun. Values obtained by reversal of the characteristic radiation just mentioned did not agree even when corrected for the possible error due to the variation in emissivity of the tungsten comparison source. This result was not unexpected and is discussed in terms of the reaction kinetics involved. A general discussion of the significance of temperature of gaseous explosions is also presented. It is believed that techniques such as those presented should be useful in combustion research.
Relaxation of Stress in a Heat-Exchanger Tube of Ideal Material
Authors: Davis E. A.
Published: July 2022

Since relaxation tests are usually run on tensile specimens, the behavior of members under a state of combined stress is not well known. Analytical solutions of the relaxation of an elasticoviscous tube in a rigid tube sheet in both plane stress and a modified plane strain are worked out. The effect of reloading tensile specimens in relaxation is discussed and results of tests on an aluminum alloy are presented to illustrate these effects.
A Contribution to the Problem of Designing Radial Turbomachines
Authors: Balje O. E.
Published: July 2022

A method is outlined for computing the characteristic values, such as pressure coefficient and efficiency of centrifugal compressors and radial inward-flow turbines, as function of Reynolds number and Mach number, whereby the latter values are defined in such a manner as to represent the weight flow and the pressure ratio of the turbomachine. The influence of blade number, blade angle, speed and diameter ratio of the impeller on the efficiency and pressure coefficient is discussed. The application of this method for computing the characteristic of a particular turbomachine is shown.
Operation and Performance of Modern Reheat Boilers
Authors: Loughin P. R. , Poor H. H.
Published: July 2022

This paper illustrates typical designs of reheat boilers and discusses operating procedures for normal start-up, quick start-up, normal operation, and shutdown under normal or emergency conditions.
Some Design Factors Relating to Performance and Operation of Reheat Boilers
Authors: Hemenway H. H.
Published: July 2022

Reheat boilers designed to operate with low furnace exit-gas temperatures and at the same time to provide control of superheater and reheater-outlet steam temperatures over a wide load range are illustrated and described. Various means for controlling primary and reheat-steam temperatures are discussed as are design provisions for some of the operating and maintenance problems peculiar to reheat units. Some advantages and disadvantages of indirect reheating are given.
Summary of Investigation of Two-Stroke-Cycle Gas-Generator Aircraft Engine
Authors: Sather B. I. , Schuricht F. R. , Biermann A. E.
Published: July 2022

An investigation of a two-stroke-cycle gas-generator type of aircraft engine is described. A theoretical analysis of the performance of the ideal gas-generator engine, an analysis of methods of achieving ideal performance when the engine components are fixed, and some experimental results are included. The experimental work was performed on the reciprocating component only and consisted of data obtained from three types of two-stroke-cycle single-cylinder test engines. Information presented in previously published NACA reports on the gas-generator engine together with some unpublished work on component requirements and gas-generator evaluation are summarized. Certain practical problems connected with the gas-generator type of engine are discussed also. The results of this investigation indicate that an engine of the two-stroke-cycle gas-generator type would provide a power plant of low specific weight and fuel consumption with favorable altitude performance characteristics. It was found possible to operate a two-stroke-cycle cylinder at the pressure and temperature levels required for the gas-generator engine. Mechanical functioning of the piston engine under gas-generator operating conditions was, in general, satisfactory.
Angles for Machining
Authors: Spotts M. F.
Published: July 2022

For a machining operation, trial and error is ordinarily used to orient an inclined plane of a workpiece into the proper position on a machine tool. This process is wasteful of time and often results in spoiled work. This article attempts to correct the situation by describing in detail some simple mathematical methods for calculating the angles required to rotate the inclined plane into the horizontal. Numerical examples accompany all the mathematical developments.
Hydraulics Applied to Molten Aluminum
Authors: Richins D. S. , Wetmore W. O.
Published: July 2022

It has long been recognized in foundry practice that visual agitation or riling of molten metals susceptible to dross formation or gas absorption may affect casting quality adversely. Accordingly, flow systems are continually being sought which permit the flow of quiet nonriled metal at controlled delivery rates. Some of the more common fluid-dynamic properties of a molten aluminum alloy when flowing in sand ducts are reported in this paper. These were evaluated in the initial phase of an investigation to determine the effects of various configurations of casting flow systems upon casting quality.
Rupture and Creep Characteristics of Titanium-Stabilized Stainless Steel at 1100 to 1300 F
Authors: Freeman J. W. , Comstock G. F. , White A. E.
Published: July 2022

Rupture and creep strengths were established at 1100, 1200, and 1300 F for 18-8 + Ti steel heat-treated at 1900 and 2050 F. Several Ti/C ratios were included as a variable. Creep and rupture strengths were higher for the higher-temperature heat-treatment. The lower Ti/C ratio steel had the higher strengths for a given heat-treatment, although this effect was somewhat less than that of temperature of heat-treatment. Limited tests indicated that water-quenching prior to testing slightly improves strength at 1100 F and reduces it at 1300 F. The steels varied in susceptibility to sigma-phase development during testing. The lower Ti/C ratio steels were less susceptible than the higher. In the commercial steels tested, those steels which developed sigma phase had abnormal creep characteristics, with first-stage creep virtually absent and increasing creep rates at short-time periods and low creep rates. This indication of premature third-degree creep was false in that prolonged testing established a true secondary creep rate as predicted by the rupture tests. Use of the minimum creep rates of short duration for establishing the usual creep strengths led to values estimated to be 1000 to 3000 psi high. The creep and rupture strengths of 18-8 + Ti and 18-8 + Cb steels probably have about the same range in strengths at high temperatures. Under present specifications it is entirely possible to have very low or very high strengths for both steels.
How to Obtain Instrument Accuracy With Proportioning Pumps
Authors: Swarr J. N.
Published: July 2022

Proportioning pumps can be used as flow-rate controllers to good advantage, if the stroke and speed are known and controllable, and if the volume discharged by the pump is equal to its displacement. The discharge may be greater or less than the displacement, depending upon the relationships between such parameters as rate of plunger displacement, friction losses in the suction-side and discharge-side piping, masses of liquor in both the suction and discharge lines which must be accelerated and decelerated at each stroke, elevations of supply and discharge tanks, and so forth. The relationships between these factors, as they affect pump volumetric performance, are eveloped on a theoretical basis, and simple tests are devised which will enable an engineer to predetermine whether or not a proposed installation will be satisfactory, and which indicate what changes must be made to correct an unsatisfactory design. The conclusion is drawn that the range of conditions under which a proportioning pump will give satisfactory performance as a meter is considerably restricted so that a careful and thorough analysis of each proposed installation is essential.
Discharge Coefficients of Herschel-Type Venturi Tubes
Authors: Jorissen A. L.
Published: July 2022

An analysis has been made of a large number of calibration curves of Herschel-type Venturi tubes, in order to obtain average values of the coefficient of discharge, both in the range of constant coefficient and of coefficient varying with Reynolds number. The data furnished by American practice have been compared with foreign standards of flow measurement.
Dynamic Buckling of Thin Elastic Plates
Authors: Zizicas G. A.
Published: July 2022

The behavior of thin elastic plates under loading parallel to their middle plane, constant or arbitrarily varying with time, is considered. The effect of vibrations in the middle plane is examined. In the transverse direction it is shown that by introducing appropriate nondimensional variables and parameters the time dependence reduces to the same type of equation as in the case of columns. Thus the fundamental features of plates and columns are similar. Additional discussion and examples of the solution of the nondimensional equation are presented. Higher modes are related to the fundamental mode of the same plate under appropriate different loading. The need of considering the entire time history of the loading is shown by examples. Shear loading and various boundary conditions are discussed. For loading constant during the time of application initially curved and eccentrically loaded plates are proved equivalent models for the investigation. A slight modification is necessary for a load arbitrarily varying with time.
The Process Characteristics Which Affect Automatic Control
Authors: McMahon J. B. , Ackley R. A.
Published: July 2022

The important process factors which affect the application of automatic control are discussed under three headings: (a) In the section for selection of criteria of process conditions, it is emphasized that the factors selected to represent process operating conditions must truly represent the conditions and bear a substantially linear relation to them. Discontinuities are to be avoided. (b) Self-regulation is a sustained reaction inherent in a process which assists or opposes the establishment of equilibrium. Its presence or absence may determine whether or not automatic control is practical. Typical examples are given. (c) Process lag is classified under six different types of common time reactions. A qualitative discussion points out which types of lag and lag combinations assist and which oppose good automatic-control results. The effect of automatic-control arrangement and regulator performance are brought out. Hydraulic examples of process-lag combinations are presented, with the corresponding reaction curves.
Radial-Flow Compressors and Turbines for the Simple Small Gas Turbine
Authors: Wosika L. R.
Published: July 2022

This paper describes the procedure followed in developing an acceptable radial-flow turbine for use with a lightweight gas-turbine-driven fire pump for the Navy Bureau of Ships. In the course of this work considerable data were accumulated on general design information and practice on radial compressors and turbines. A review is given of these data as well as the current design approach for a simple cycle radial-flow gas turbine. A discussion of the factors and variables which affect the performance of radial turbomachines is included.
Machining of Heated Metals
Authors: Armstrong E. T. , Cosler A. S. , Katz E. F.
Published: July 2022

Studies are reported of the machinability of several materials at elevated temperatures. It was found that tool life, cutting austenitic stainless steel, was increased tenfold by heating to 400 F. High-temperature alloys, including vitallium, machined freely at temperatures from 700 F to 2000 F. Long curling chips and a smooth cleanly cut surface were produced in hot-machining. The same materials cut at room temperature developed a glazed uneven surface, and the chips were powdery. Austenitic manganese steel machined easily at 1200 F, as did fully hardened high-speed steel. An arc heating method was developed which permitted continuous heating while machining, without heating the work throughout.
Metals for High-Pressure Hydrogenation Plants
Authors: Nelson G. A.
Published: July 2022

Many of the important chemicals of today’s industrial economy require processing in the presence of hydrogen, at elevated temperatures and pressures, at some stage in their manufacture. The more familiar ones are ammonia, methanol, edible oils, and higher alcohols. In the petroleum-refining field, hydrogenation processes are becoming more and more important. In the future it can be anticipated that greater need for hydrogenation processes may arise, for example, hydrodesulphurization of crude oils or fractions therefrom, hydrogenation of carbon monoxide (Fischer-Tropsch), and destructive hydrogenation of oil residues or coal (Bergius process). These processes operate at high temperatures and pressures, where ordinary steels have their limits for safe operation. Although high-alloy steels can be used under these conditions, oftentimes more reasonably priced low-alloy steels are satisfactory. This paper summarizes the results of tests and data from operating plants, from which it is possible to establish practical operating limits for carbon and alloy steels for all degrees of severity of service. Additional corrosive effects by sulphur, nitrogen, and carbon monoxide are discussed.
Report of Progress on Measurements of Friction Coefficients, Recovery Factors, and Heat-Transfer Coefficients for Supersonic Flow of Air in a Pipe
Authors: Kaye Joseph , Keenan J. H. , McAdams W. H.
Published: July 2022

Measured values are presented for friction coefficients, recovery factors, and heat-transfer coefficients for a stream of air flowing through a pipe at Mach numbers ranging from 2.5 to 1.2. The friction coefficients are in good agreement with those of Keenan and Neumann. At a diameter Reynolds number at inlet of about 1 × 105, which is intermediate between values observed by Keenan and Neumann, frictional effects of a very low order were observed. Maximum frictional effects occurred at a diameter Reynolds number at inlet of about 1.5 × 105. Friction coefficients are, in general, considerably lower than those for fully developed turbulent flow of incompressible fluids at the same values of the Reynolds number.

For laminar boundary layer, it appears that the recovery factor is in close agreement with the results of the Pohlhausen analysis, namely (Pr)1/2 or 0.865. For turbulent boundary layer the recovery factor appears to vary from about 0.79 where the Mach number is 1.3 to about 0.865 where the Mach number is 2.2. It cannot be determined from the present tests whether this variation is primarily an effect of variation in Mach number, although it probably is.

The measured values of heat-transfer coefficient in the region of laminar boundary layer seem to be roughly in accord with the Pohlhausen analytical values for incompressible flow over a flat plate. In the region of greatest turbulence in the boundary layer, agreement with the McAdams correlation of data for turbulent flow in pipes is good. The major portion of the data obtained appears to be in the region of transition in the boundary layer from laminar to turbulent flow. Most of the observed values of heat-transfer coefficient are smaller by far than the corresponding ones for fully developed turbulent flow—the ratio of one to the other being as small as 1 to 10.
Residual Grinding Stresses in Mild Steel
Authors: Frisch J. , Thomsen E. G.
Published: July 2022

A method for determining residual surface stresses is presented. For their determination, it is necessary to remove small layers from the part which has been bent by the residual stresses in the unrestrained state and to measure the resulting change in deflection and thickness of metal removed. Etching with a weak nitric acid and water solution was found to be a satisfactory method for removing surface metal without introducing additional stresses. Mild-steel bars were ground with a medium-soft grinding wheel in a surface grinder. The depth of surface layer containing residual stresses extended to approximately 0.012 in. to 0.018 in. below the surface for grinding cuts ranging in depth from 0.0003 in. to 0.003 in. The thickness of the layer containing residual stresses increases with increasing depth of grind. The maximum residual stress occurs on the surface and, for all depths of grinds, was considerably above the yield point of the original material. The maximum surface stresses when grinding mild steel within the foregoing range of depth of cut decreases with increasing depth. It is believed that this phenomenon can be explained by the possible partial recrystallization of the surface grains because of the higher surface temperatures obtained with heavy cuts.
Stress Distribution in the Continuous Chip—A Solution of the Paradox of Chip Curl
Authors: Henriksen E. K.
Published: July 2022

This paper is intended to throw light upon the hitherto unsolved problem of chip curl. The chip passes along the tool face for a certain distance before it leaves the tool and then curls through space. The author assumes that a sudden drop in pressure occurs at the point of ultimate contact, which combines with a single force at this point. The physical origin of this system of forces is explained by surface roughness of the tool, which leads to an explanation of the sharp boundary line for the area of wear on the tool face. Distribution of pressure between chip and tool follows an exponential law. Methods of stress analysis are explained which should be useful in further investigations.
Index Testing of Hydraulic Turbines
Authors: Voaden G. H.
Published: July 2022

The object of this paper is (a) to bring to the attention of operating companies the benefits derived from index tests of hydraulic turbines, and especially those of the adjustable-blade propeller or Kaplan type; (b) to enumerate and discuss the presently known methods of determining relative discharge and hence relative efficiency; (c) to present an example of an index test of an adjustable-blade propeller turbine in sufficient detail to provide a guide for the conduct of such a test.
A Method for the Calculation of Heat Transfer in Solids With Temperature-Dependent Properties
Authors: Plunkett Robert
Published: July 2022

The problem of heat transfer in a solid, whose conductivity and specific heat depend on the temperature, is converted by a simple change of variable to one in which the conductivity may be held constant, and only the specific-heat term varies with temperature in a way which depends upon the variation of both parameters. The method is illustrated by application to a problem previously solved by Dusinberre in a different way. The effect on the final solution of different finite approximations to the derivatives is also discussed.
Performance of Oil-Film Bearings With Abrasive-Containing Lubricant
Authors: Roach A. E.
Published: July 2022

This paper describes an experimental study of the embedability of bearing materials, i.e., the ability of bearing materials to operate on lubricants containing abrasive particles. It is found that the rate of temperature rise suffered by the bearing when abrasive-containing oil is introduced into it offers a convenient criterion for rating the embedability performance of various bearing materials. Data are presented on the effect of varying babbitt-overlay thickness and copper-lead composition of gridded surfaces and of oil grooves. Relative embedability ratings for seventeen different bearings are correlated with wear rates.
The Effect of Oil Viscosity on the Power-Transmitting Capacity of Spur Gears
Authors: Borsoff V. N. , Accinelli J. B. , Cattaneo A. G.
Published: July 2022

In tests made on spur gears with mineral oils of various viscosities, it was observed that a relationship exists between the maximum horsepower which the gears can transmit without scoring, and the product of gear speed and lubricant viscosity. An analysis of the factors entering into this relation indicates that these are the same that occur in Lewis’ equation used in gear design, except that the latter does not contain the lubricant viscosity. If this viscosity is introduced into the Lewis equation, the latter represents the experimental points for horsepower transmitted at the onset of scoring very well over a wide range of speeds and lubricant viscosity. This modified Lewis equation appears to apply to spur gears, in general, and indicates that the influence of lubricant viscosity on the power-transmitting capacity of gears is much too great to be neglected in the design of gears.
An Introduction to Arc-Cast Molybdenum and Its Alloys
Authors: Ham J. L.
Published: July 2022

The advantages and limitations of the arc-casting method for producing metallic molybdenum and its alloys are discussed. The general properties of unalloyed cast molybdenum are described and curves are presented to show the room temperature tensile properties, hardness, and notched-bar values after annealing at various temperatures, the effect of testing temperature on hardness, and the transition temperatures for various types of impact tests.

The need for addition of alloying elements is discussed. Preliminary selection of appropriate alloying elements was based on their vapor pressures and known or expected solid solubility limits. Curves are presented showing the solid solubility limits of silicon, aluminum, iron, cobalt, and nickel in molybdenum at various temperatures as determined by the measurement of lattice parameters of arc-cast samples, and the effects of beryllium, aluminum, silicon, titanium, vanadium, chromium, iron, cobalt, nickel, zirconium, columbium, tantalum, and tungsten on the hardness of molybdenum at various temperatures.

Molybdenum containing a small amount of beryllium can be hardened by quenching and softened by slow cooling.

Regardless of which alloying element is used, there appears to be a limit to the increase in hardness that can be tolerated without causing difficulty in hot-working by the techniques applied so far.

The effects of several of the alloying elements on the rate of work-hardening and on the temperatures of softening and recrystallization were studied using a series of alloys which were extruded.
Experience With Austenitic Steels in High-Temperature Service in Petroleum Industry
Authors: Holmberg M. E.
Published: July 2022

Experience in the petroleum industry shows there are other factors besides tensile, creep, and stress rupture to consider in the use of austenitic steels in high-temperature service. There is no advantage in using stabilized grades in many applications. A spheroidizing heat-treatment is generally effective where stabilized steel is required. The coefficient of expansion and the thermal conductivity have been important factors in thermal-shock and thermal-fatigue failures in austenitic steels.
An Investigation of the Role of Aluminum in the Graphitization of Plain Carbon Steel
Authors: Hall A. M. , Fletcher E. E.
Published: July 2022

This investigation was sponsored by Project No. 29 of the Joint ASTM-ASME Committee on the Effect of Temperature on Properties of Metals, and was directed toward casting more light on the role of aluminum in the breakdown of iron carbide in plain carbon steels into iron and graphite at temperatures below the lower critical point of the steel. The approach to the problem was to extract the carbides from several plain carbon steels which had been deoxidized with different amounts of aluminum and had different known degrees of susceptibility to graphitization, and then to examine and analyze the extracted carbides, with particular attention to the amount and form of the aluminum therein. By comparing the aluminum found in the carbide with the aluminum of the original steel, data were obtained on the role which that element appears to play on the graphitization process. The results strongly suggest that a graphitization-resistant plain carbon steel does not differ fundamentally from one which graphitizes readily. It is tentatively concluded that, in order to promote graphitization, the aluminum is either in solid solution in the ferrite matrix, or else fixes the nitrogen as AlN. Which of these forms it takes could not be determined from the results. The results further suggested that any aluminum which might be associated with the carbide phase is not influential in determining the degree of susceptibility to graphite formation.
A New Method of Determining Thermal Diffusivity of Solids at Various Temperatures
Authors: Rosenthal D. , Ambrosio A.
Published: July 2022

The method under review affords a rapid means of determining thermal diffusivity and is especially suitable to measurements at high temperatures. The theory of moving heat sources is the basis for this method. When the theory is applied to the case of unidimensional heat flow in a long prismatic bar, being heated by a moving point heat source, an equation which permits the computation of thermal diffusivity at each temperature is obtained. The experimental technique involves the measurement of the temperature-time history at a single point of the bar, using two different heat-source velocities. The method was tried on a commercial “yellow” brass tube, but the equation derived for the computations proved to be unworkable owing to the poor accuracy attending the evaluation of the first and second-order derivatives of the temperature-time curves. To avoid this shortcoming another equation was derived by assuming that the thermal properties of the bar are constant in small intervals of temperature. This equation gives average values of diffusivity in the small intervals of temperature, rather than a specific value for each temperature. This approximation notwithstanding, the intervals of temperature could be made small enough to determine the values of thermal diffusivity of the brass specimen in the range 100 to 400 C with a repeatability of ±3 per cent. These computed values compare favorably with those found in the literature.
Coal Sampling by Large-Increment Weights
Authors: Landry B. A. , Anderson W. W.
Published: July 2022

A sampling experiment is described that was aimed at determining the variance in percentage ash of large-weight, single-increment samples of an Indiana coal. The observed variance is broken down into its component parts which are calculated from the data obtained. Results show that for increments of large weight, such as are taken by mechanical samplers, at large steam-generating stations, relatively few would be required, for the coal studied, to obtain a gross sample meeting present accuracy standards. The suggestion is made that studies on other coals should be made to confirm these findings which, if generally true, may lead to an upward revision of standards of accuracy in view of the practicability of taking larger numbers of increments mechanically.
Some Economic Factors in the Selection of Cooling Towers
Authors: LeBailly A. R.
Published: July 2022

This paper deals with performance studies of selected condenser-cooling tower combinations and their economics. Comparison is made between the cost of circulating-water supply from a river source with the cooling tower.
Cooling Towers for Steam-Electric Stations—Economic Applications
Authors: Elliott Louis
Published: July 2022

The paper outlines a method of making economic comparison as between the use of a cooling tower and a direct-condensing arrangement for a steam station; the method is illustrated by analyzing a specific problem. Remarks on the placing of cooling towers are included, and problems requiring research are mentioned.
Corrosion-Erosion of Boiler Feed Pumps and Regulating Valves at Marysville, Second Test Program
Authors: Decker J. M. , Wagner H. A. , Marsh J. C.
Published: July 2022

Corrosion-erosion tests at 320 and 385 F indicated that, at these temperatures, carbon steel is attacked to a lesser extent than at 250 F, whereas the reverse is true of the chromium-bearing steels. However, the rate of attack of the chromium steels is still only a fraction of that of carbon steels, so that use of the alloy steels for boiler-feed-pump parts is warranted at the higher temperatures also. Increasing the pH of the feedwater from 7.6 to 8.4 doubled the corrosion-erosion attack on carbon steel in the Marysville boiler feedwater at 250 F, as compared with previous tests at the lower pH. Of two bronzes tested, Navy M material appeared satisfactory at temperatures up to 320 F; a leaded bronze was unsatisfactory at all test temperatures in this program.
Development of the Hydraulic Design for the Grand Coulee Pumps
Authors: Blom Carl
Published: July 2022

The Grand Coulee pumping plant has been the subject of an extensive hydraulic research program. The first part of this program was conducted at The California Institute of Technology for the Bureau of Reclamation from January, 1938, to July, 1940. Some of the results of this program have already been published (1 to 4), and other papers (5, 6) describe the different features of this project. This paper presents some of the results of continued experimental research of the author’s company from 1943 to 1946. The investigation covered the effects of various diffuser-type pump cases and impellers on the pump characteristics of the Grand Coulee model. The paper concludes with the description of the final test of the contractor’s model completed in July, 1947.
Effect of Fuel-Immersion on Laminated Plastics
Authors: Crouse W. A. , Carickhoff Margie , Fisher Margaret A.
Published: July 2022

The effects of cyclic and of continuous immersion in heptane, toluene, and SR-6, a test fuel, on the weight, dimensions, and flexural properties of nineteen samples of laminated plastics are reported. No one sample exhibited smaller changes than all other samples in all properties for all fuels, and for both cyclic and continuous immersion. The best weight and dimensional stability in the cyclic test was shown by a glass-fabric unsaturated-polyester laminate. The changes in flexural strength as well as in modulus of elasticity were losses in the majority of cases after the cyclic- and the continuous-immersion test. The unsaturated-polyester laminates varied widely among themselves in regard to the magnitude of the changes in a given property after an immersion test.
The Design of Sewaren Generating Station and No. 1 Unit at Essex Station, Public Service Electric and Gas Company
Authors: Fairchild F. P.
Published: July 2022

The author outlines the more important considerations leading to the design of the 100,000-kw unit at Essex and the four-unit Sewaren Generating Station. Outstanding features are semioutdoor boilers at latitude 41°; 1050 F steam temperature; a simplified plant layout, including the unit system; central control; shaft-end house generators; and all-electric auxiliary drive. The improvements in calculated plant heat rates are shown for the progressive steps of the program. Some of the more important electrical and architectural features are described.
Frictional Characteristics of O-Rings With a Typical Hydraulic Fluid
Authors: Cheyney L. E. , Mueller W. J. , Duval R. E.
Published: July 2022

O-ring packings employed in aircraft hydraulic systems are subject to numerous operating variables, which affect the friction involved in their operation. A method for studying the friction is described, and the effects of several variables—pressure, time delay, squeeze, stroke speed, ring size, and surface finish of the moving metal part—have been determined.
Theoretical Considerations on the Optimum Adjustment of Regulators
Authors: Hazebroek P. , van der Waerden B. L.
Published: July 2022

In a companion paper, the authors propose some practical rules for the best possible adjustment of the parameters of automatic regulators with proportional-plus-integral action. The present paper will be concerned with the theoretical foundations of the method developed.
Investigation of Lubricants for Power Circuit Breakers
Authors: Bush R. R.
Published: July 2022

This paper describes a technique for the selection of proper lubricants for power circuit breakers. The circuit breaker is described briefly, and its lubrication requirements for dependable operation are discussed. The laboratory methods set up to determine the performance of the grease best suited for this application are outlined. Results of the laboratory test data are shown and evaluated with reference to circuit-breaker requirements. Properties of some typical greases are compared with their performance for this particular application. Because performance depends not only upon grease properties, but also upon the process of manufacture, the greases tested are referred to only in code. Life tests on actual circuit breakers have checked laboratory results. Therefore it is concluded that tests may be set up to determine the suitability of a lubricant for any particular application and especially for power circuit breakers.
Philadelphia Electric Company Adopts Mobile Coal-Handling Equipment
Authors: Russell E. C.
Published: July 2022

The paper covers the change from storing and reclaiming coal by cranes and locomotives to the use of standard self-propelled earth-moving equipment. The size and type of equipment are described, as well as its use. The change in design of storage piles is also considered. Description of new storage systems designed for the use of mobile equipment is presented. An analysis of operating costs and capacities is made with a comparison of the two methods.
Storing and Reclaiming Coal With Earth-Moving Equipment at the Oswego Steam Station
Authors: Ewart J. N.
Published: July 2022

Earth-moving equipment at the Oswego Steam Station of the Central New York Power Corporation has handled in excess of 3 billion ton-feet of coal during its first 9 years of operation. Coal is stored in a single pile 100 ft high with no danger of spontaneous combustion. The paper describes the operation of bulldozer-carryall units and presents operating and maintenance costs.
Theory of the Mechanical Properties of Hot Plastics
Authors: Loring S. J.
Published: July 2022

This paper describes a theory of large strain, rubber-like elasticity combined with stress relaxation, which is the character of the behavior of hot plastics indicated by a series of unpublished high extension rate tests on such materials as polystyrene, polyethylene, acetate, etc., in the molten or “soft” state.
Sulphite and Silica in Boiler Water at Springdale
Authors: Hankison L. E. , Baker M. D.
Published: July 2022

Hydrogen sulphide was first detected in the gases discharged from the air ejector of the main condenser of No. 7 unit at Springdale Station of West Penn Power Company about 6 months after the unit was placed in service. The story of potassium sulphite and its connection with this unit will form the first part of this paper. Silica deposition on the turbine blades was quite rapid, and after 8 months operation it was necessary to sandblast the silica from the blades. The search for the source of this silica, together with the information found and the corrections applied, will also be discussed.