bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Velocity on Tensile Impact Properties of Polymethyl Methacrylate
Authors: Maxwell Bryce , Harrington J. P. 
Published: July 2022

Abstract
The history of impact testing of plastics is reviewed and the current theories of impact resistance are discussed. The effect of velocity on the energy absorbed by polymethyl methacrylate at various temperatures has been studied with the aid of two new testing machines. The results are interpreted in terms of the classical theories of mechanics of materials and the current theories of the rheology of high polymers. It is concluded that there are two distinct critical velocities of straining in this material—the lower one corresponding to the relaxation of the bonds restraining chain-chain slipping and the higher one corresponding to the relaxation of the secondary bonds involved in chain uncoiling. Both of these relaxations are temperature dependent—the lower one to a slight extent and the upper one to a marked extent. Above the two critical velocities the response of the material is purely elastic. A method of calculating the energy to break at rates of straining above the second critical velocity from the slow-rate stress-strain curves is demonstrated.
The Development and Implementation of a Generation Program on the American Gas and Electric Company System: 2—Fuel Supply
Authors: Sporn Philip , Kammer H. A. 
Published: July 2022

Abstract
This paper discusses the engineering and economics of fuel supply for the generating plants of the American Gas and Electric Company System, and in particular the fuel supply for two new plants—Kanawha River of Appalachian Electric Power Company, and Muskingum River of The Ohio Power Company. The importance of adequately planning fuel supply for a large power system is stressed, and the fundamental considerations of adequacy of supply, reliability, characteristics of supply, coal storage, and transportation are discussed with reference to the System characteristics, and with special emphasis on the development of the fuel supply for the two new plants.
Hysteresis of Shaft Materials in Torsion
Authors: Welch W. P. , Cametti B. 
Published: July 2022

Abstract
Static determinations of hysteresis of typical shaft materials in torsion show that the values are low for high-quality materials in unidirectional loading after several cycles of loading up to a shear-stress amplitude of 24,000 psi. For reversed loading, the hysteresis becomes several times larger and may be of significance in accurate torque-weighing devices. The measured hysteresis in a tubular specimen had values 3 to 4 times that for a solid specimen. Two nonmagnetic materials displayed very low values of hysteresis. The apparatus developed for this investigation had sensitivity sufficient to measure displacement changes of 0.002 per cent of the full-load deflection, and was designed to eliminate errors due to temperature changes, extraneous loads, and external vibration.
On the Solution of the Reynolds Equation for Slider-Bearing Lubrication—I
Authors: Charnes A. , Saibel E. 
Published: July 2022

Abstract
An exact solution is developed for the Reynolds equation in the hydrodynamical theory of slider-bearing lubrication with side leakage for film thickness varying exponentially. This solution is in the form of a rapidly convergent series from which calculations for the pressure distribution, total bearing load, and center of pressure may be made rapidly for all values of the parameter concerned. The results are in close agreement with those which have been obtained for the plane slider bearing by cumbersome methods, and it is proposed not only to use the present solution for the plane case, but also to show the design possibilities for a much wider variety of shapes by using various portions of exponential curves.
Basic Difficulties in Pulsating-Flow Metering
Authors: Deschere A. R. 
Published: July 2022

Abstract
Practically all research work in the field of flow metering has been devoted to a development of devices for obtaining an average of the square root of the pressure differential, and means for preventing distortion of the pressure transmission in the lines connecting the primary to the secondary part of the meter. The author shows that, in measurement of severely unsteady flow, these may not be the most important factors, but rather that the primary element itself does not give a response in this type of flow which can be interpreted correctly by the usual steady flow-metering methods.
Progress Report on the Study of Supercompressibility Factors for Natural Gases
Authors: Zimmerman R. H. , Beitler S. R. 
Published: July 2022

Abstract
A report is given on the present status of an evaluation of supercompressibility factors of natural gases. The aim of the research work is an attempt to establish an accurate method for the prediction of these factors within the pressure range 0 to 4000 psi and in terms of gas properties generally known or conveniently determined. The working method used to predict supercompressibility factors is based on the method proposed by Dunkle in 1944. Results of the method are compared with supercompressibility factors experimentally determined on the Burnett deviation apparatus.
Heat Transfer by Gas Conduction and Radiation in Fibrous Insulations
Authors: Verschoor J. D. , Greebler Paul 
Published: July 2022

Abstract
Thermal conductivity measurements were made on samples of an experimental glass fibrous insulation ranging in density from 0.5 to 8.4 pcf. Tests were carried out at atmospheric pressure with four different gases in the insulation samples, and the thermal conductivity with air was studied over a pressure range of 1 micron to 760 mm of Hg. Gas conduction is the most important mechanism of heat transfer. A theory of gas conduction in fibrous insulations was developed, and agrees well with experimental results. Theoretical considerations of heat transfer by radiation were confirmed by the experimental thermal conductivity values at low pressures. Methods are discussed of producing considerable reduction in the thermal conductivity of fibrous insulations.
Heat Transfer and Pressure Drop for Turbulent Flow of Air-Water Mixtures in a Horizontal Pipe
Authors: Johnson H. A. , Abou-Sabe A. H. 
Published: July 2022

Abstract
The static pressure drop and heat transfer for two-phase, two-component flow of air and water were measured for flow in a horizontal 15-ft length of 1-in. 16-gage brass tubing. Flow rates include the range of 1000 to 15,000 lb per hr for the water and 0 to 200 lb per hr for the air. Tentative correlations are presented from which prediction of pressure drop and heat transfer may be made under restricted flow conditions.
Tool Forces and Tool-Chip Adhesion in the Machining of Nodular Cast Iron
Authors: Trigger K. J. , Zylstra L. B. , Chao B. T. 
Published: July 2022

Abstract
This paper presents the results of an investigation on the machining characteristics of nodular cast iron in both the as-cast and the annealed conditions. Tool forces, cutting temperatures, and tool-chip contact areas are compared for different grades of cemented-carbide tools. An adhesion phenomenon observed with this material provides evidence in support of the oxide-film theory and provides an explanation for some of the differences in wearing qualities of cemented-carbide tools.
A Comparison of Parameters for the Machining of Gray Cast Iron
Authors: Colwell L. V. , Holmes H. J. , Rote F. B. 
Published: July 2022

Abstract
This investigation was designed to compare several types of data as parameters for predicting cutting speeds for gray iron. A series of eleven irons, representing ranges of alloys, ferrite, graphite, and mechanical properties was used in the study. Cutting forces, power, and energy were determined from drilling and milling tests, and cutting speed - tool life lines were determined for each of the irons. Finally, correlations were attempted between the cutting speed (V20) for a 20-min tool life, and all other available types of information. The net result of this approach was a comparison of the relative reliability of the different types of data. This comparison showed that combined carbon, microhardness, and the nucleation or graphitizing tendency hold the greatest promise of developing into reliable parameters, while Brinell hardness, tensile strength, drilling forces, and milling power show little promise of providing useful information. This study was preliminary in nature and was intended only as a screening process for narrowing down the field for future investigations. Consequently, the correlations between cutting speed and combined carbon, microhardness, and nucleation tendency are undeveloped, and applications should not be attempted without further investigation.
On the Accuracy of Extrapolated Creep-Test Relations for Plexiglas Subjected to Various Stresses
Authors: Marin Joseph , Pao Yoh-Han 
Published: July 2022

Abstract
Most creep-time relations for materials are obtained for short periods of time—usually for 1000 hr or about 40 days. In many applications, however, the life of the member is much greater than 1000 hr. In the design of these members, therefore, it is necessary to provide for creep deformations which cover periods of time much greater than 40 days. To do this, it is common practice to obtain a stress-creep-time empirical relation based on 1000-hr test data, and to extrapolate these relations to periods of time representing the service life of the part. The purpose of this paper is to determine the accuracy of this extrapolation. This is accomplished by comparing the extrapolated tension and compression creep-time relations based on 1000-hr test data with actual 10,000-hr creep-test data. Long-time creep-test data also were obtained for pure bending and pure torsion. These creep-time relations were compared with theoretical values based on empirical relations for 1000-hr tension and compression creep data. For the relations used and for the material tested, it was found that the extrapolated values gave good engineering approximations to the actual values.
Heat Transfer From Spheres to a Rarefied Gas in Supersonic Flow
Authors: Drake R. M. , Backer G. H. 
Published: July 2022

Abstract
An approximate analysis is presented for the prediction of the over-all average heat-transfer coefficients from spheres to air in the transition-flow region, that region wherein the mean free molecular path is small but not negligible when compared with the sphere diameter. The analysis is made on the basis of a simplified flow field and the utilization of the continuum formulation of the energy equation with the rarefaction effects being accounted for entirely in the boundary conditions. The results of the analysis are compared with experimental heat-transfer data from spheres to air in the transition-flow region, with heat-transfer data from spheres to air in the continuum-flow region, and with the calculated results of heat transfer from spheres in the free molecule-flow region. Experimental free-stream recovery factors are presented for spheres. Significant flow parameters and flow-region limits for the transition region are discussed.
Friction Surfaces for Spin-Up Simulation in Landing-Gear Drop Tests
Authors: Drake D. W. 
Published: July 2022

Abstract
Current procedures for drop testing of landing gears entail the simulation of wheel spin-up. The use of a fixed reaction surface in conjunction with spinning wheels in the drop tower introduces friction conditions between the tire and reaction surface that do not permit direct use of airport surfaces such as concrete. For this reason the “coefficients of friction” of a number of reaction surfaces have been evaluated and their value for spin-up simulation is discussed.
The Mean Flow in Kaplan Turbines
Authors: Meyer R. E. 
Published: July 2022

Abstract
All theories now in use for the design of the bladings of Kaplan turbines and pumps are based on the assumptions that the fluid moves on concentric cylinders and that no trailing vorticity is shed off the blading. Approximate corrections are here found arising from the fact that the flow does not, in practice, satisfy these assumptions. These corrections are the more important the smaller the ratio of hub diameter to tip diameter. An approximation to them is found from investigation of the axially symmetrical mean flow in the rotor, which is obtained when the velocity components at any point are replaced by their mean values with respect to the angular co-ordinate. This approximation is the more accurate the smaller the pitch-chord ratio. It is found that the three-dimensional effects in the flow are due to the transverse component of the vorticity (“ring vorticity”). Formulas for the velocity components induced by it are given. Two distinct problems arise in connection with the design of a Kaplan blading, viz., (a) to find the shape of the blade and the pressure distribution for a prescribed load distribution, under the optimum working condition, and (b) to find the performance and pressure distribution for a prescribed blade shape, after a change of pitch. The theory applies also to multistage axial-flow turbomachines where the mean velocity is not too high for knowledge of the incompressible flow to be of interest.
Instrumentation for Axial-Flow-Compressor Research
Authors: Meyer C. A. , Benedict R. P. 
Published: July 2022

Abstract
A discussion of many of the air-flow instruments currently used in compressor research is given. A history of the development of some of the instruments is presented together with the reasons for adopting the present designs. Optimum dimensions, based on test data, are included for claw probes, cylindrical probes, spherical probes, and averaging probes. Errors encountered in temperature measurement by means of thermocouples are reviewed, and methods for reducing these errors are suggested. A discussion of traversers is also included.
A Study of Heat Developed in Cylindrical Grinding
Authors: McKee R. E. , Moore R. S. , Boston O. W. 
Published: July 2022

Abstract
This paper, the fourth in a series on cylindrical grinding, presents some of the results of an investigation of the grinding process with particular reference to the influence of the grain size of a grinding wheel and type of grinding compound used on certain criteria; such as volume of metal removed per unit of wheel wear, unit net horsepower, surface finish, grinding rating, temperature increase in the workpiece surface, temperature increase in the grinding compound, and possible injury to the structure of the metal.
An Analytical Evaluation of Metal-Cutting Temperatures
Authors: Trigger K. J. , Chao B. T. 
Published: July 2022

Abstract
This paper presents an analytical method for the determination of metal-cutting temperatures. The average tool-chip interface temperature is calculated by considering the mechanism of heat generation during metal-cutting operations in which a type 2 chip is formed. The analytical results agree well with those obtained by test methods, and the theoretical analysis has also yielded some important physical quantities and measurements which affect cutting temperatures.
Dynamic Shear Properties of Rubberlike Polymers
Authors: Hopkins I. L. 
Published: July 2022

Abstract
A simple apparatus for determining the dynamic properties of elastomers in shear at audio frequencies is appraised. Typical values of shear modulus and viscosity for several elastomers are given, both at room conditions and at 150 F. The frequencies of test range from 100 to 5250 cycles per second, the shear moduli from 0.5 × 106 to 480 × 106 dynes per sq cm and the viscosities from 20 to 75,000 poises.
Joints for High-Pressure High-Temperature Piping
Authors: Carlson I. H. , Black W. S. 
Published: July 2022

Abstract
This paper outlines briefly the difficult problem of obtaining leakproof joints for high-pressure high-temperature piping. It includes the results obtained from an extensive test on three full-sized joints for connecting ferritic-alloy main steam piping to austenitic-alloy turbine equipment of 150,000-kw capacity. The scope of the tests was limited by the amount of steam available, but the information secured should be of value to others having similar problems. It is hoped that others having experience or knowledge in this field will contribute additional information concerning this problem which is important to the continued progress of the power industry.
Dynamic Loading of Chain Drives
Authors: Stamets W. K. 
Published: July 2022

Abstract
This paper describes the dynamic loads sustained by power chain when running at high speeds. Conditions for least destructive fatigue loading are set forth, and a formula for optimum chain speed is derived. Dynamic load tests on silent chain are reported in which the loading was measured by means of a special strain gage of the author’s design. The tests prove the loading postulated in the first part of the paper, and the conclusions indicate a new approach to chain-drive layouts for power transmission.
Effect of Molecular Weight of Entrained Fluid on the Performance of Steam-Jet Ejectors
Authors: Holton W. C. 
Published: July 2022

Abstract
A program of research sponsored by the Heat Exchange Institute involved pumping 13 pure gases and 12 mixtures of gases with small commercial single and two-stage steam-jet ejectors supplied by two manufacturers. Results were calculated in terms of “air equivalent” or “entrainment ratio,” which is the ratio of the flow rate of gas to that of air under similar conditions. Entrainment ratios were found to be a function of the molecular weight of the gases handled and were plotted as a smooth curve, which is independent of pressure, design characteristics of ejectors, and is applicable to mixture of gases. It is concluded that the curve may be used to predict results obtainable with any ejector system.
Problems Relating to Operation, Maintenance, and Chemical Control of Cooling Towers for Steam-Electric Generating Stations
Authors: Estcourt V. F. 
Published: July 2022

Abstract
In a generating station, cooling-tower performance must be considered not only in terms of heat dissipation but also in relation to the over-all results obtainable with a particular combination of tower, condenser, and turbine. There is an important relationship between turbine leaving losses and the optimum tower size. This approach to the subject involves not only the economic size of the tower but also certain operating problems which vitally affect the station heat rate. The problem of condenser-tube scale deposits is more likely to become critical where cooling towers are used, because of higher cooling-water temperatures. Successful results are described in the use of threshold treatment of cooling-tower water with stabilized phosphate in combination with sulphur burning for keeping condensers free of scale deposits. The problems of recirculation, fan-blade failures, and noise nuisance are also discussed.
Deterioration of Wood in Cooling Towers
Authors: Baechler R. H. , Richards C. A. 
Published: July 2022

Abstract
The premature deterioration of wood in cooling towers has received considerable attention during the past several years. Although the number of towers so affected appears to be rather small compared with the total number in use, premature deterioration nevertheless deserves serious study. The owner of a tower needing expensive repairs after only a relatively short period of use can draw small comfort from the fact that wood in most cooling towers gives satisfactory service. Furthermore, an upward trend in the percentage of towers affected must be recognized as a distinct possibility, making the need for corrective measures even greater than is indicated by past experience. The preliminary investigations described in this paper were intended to throw some light on a few of the many questions that have arisen regarding wood failure in cooling towers. A brief discussion of the nature of wood, the kinds of deterioration it may undergo, and the conditions to which it is exposed in a cooling tower are given.
The Nonsteady-State Load-Supporting Capacity of Fluid Wedge-Shaped Films
Authors: Gatcombe Ernest K. 
Published: July 2022

Abstract
A study is presented of the thickness and load-supporting capacity of fluid wedge-shaped films entrapped between the peripheral surfaces of rotating circular disks which are vibrated transversely, causing the wedge-shaped film to become alternately thin, then thick at moderately high frequencies. This nonsteady-state loading of the wedge is accomplished by mounting circular disks, Fig. 1, on parallel shafts with centers at d and d’, then transversely vibrating the beam which supports the complete lower-shaft assembly, consisting of bearings, bearing hangers, etc., see Fig. 4. Part 1 (see Fig. 1) is devoted to a theoretical analysis of the thickness and load-steady-state problem has yielded solutions which have not been obtainable by theoretical studies, except for cases involving assumptions which greatly alter the true results. It is found that the normal approach vibratory motion of the surfaces bounding the film is responsible for a much greater part of its load-supporting action than is the steady-state rotational motion.
Dynamic Force Reactions in Double-Ported Control Valves
Authors: King C. F. , Brockett G. F. 
Published: July 2022

Abstract
Torsional force reactions on V-port inner valves, and vertical force reactions on plug-type inner valves in double-ported control-valve bodies are of sufficient magnitude to cause concern if pressure drop is high. These forces are proportional to the mass velocity of the flowing fluid. It is possible to design inner valves so that these forces will be reduced to a point where they are not objectionable.
The Development of a Design of Smokeless Stove for Bituminous Coal
Authors: Landry B. A. , Sherman R. A. 
Published: July 2022

Abstract
This paper presents an account of an extended systematic investigation which resulted in the development of a method for burning bituminous coals in nonmechanical hand-fired heaters or stoves with substantially smokeless operation. The research was sponsored by Bituminous Coal Research, Inc., and a group of stove manufacturers. An experimental investigation of the three principles of combustion in fuel beds led to the adoption of the cross-feed principle. The design of a special grate and the research to prevent puffing, a difficulty often encountered with magazine heaters, are described. The principles of a calorimeter room in which the output of a space heater can be directly measured are presented. Data given show the thermal efficiency of a manufacturer’s model of the heater, which had an output of 41,000 Btu per hr, to be 65 per cent.
Report on Graphitization Studies on High-Temperature Welded Piping of The Philadelphia Electric Company
Authors: Abele J. B. , White A. E. 
Published: July 2022

Abstract
Summaries of the work which has been done by and for the Philadelphia Electric Company in ascertaining the degree of graphitization in the piping system in the Chester, Schuylkill, and Richmond Stations since the fall of 1946, are reported in this paper. The results of a fullsize pipe tension test on a graphitized weld section are reported. Solution treatment for removal of graphitization is described with some physical test results.
Steam-Electric Power Expansion in Southern California
Authors: Chadwick W. L. 
Published: July 2022

Abstract
This paper presents the background of the postwar expansion of steam power in Southern California, the requirements of the area served, a brief discussion of some of the war and postwar influences bearing upon power needs, the disposition of the new generation, the design trends in the area, and the influences bearing thereon. A description is given of the major features of the Redondo Steam Station of the Southern California Edison Company.