bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effect of Dispersions on Creep Properties of Aluminum-Copper Alloys
Authors: Giedt W. H. , Sherby O. D. , Dorn J. E. 
Published: July 2022

Abstract
The creep properties of a system of 3 to 5 per cent Cu in A1 alloys containing hard particles of CuAl2 were investigated throughout a temperature range of 350 to 578 K. The results supplemented with additional tensile-test data show that these properties are primarily dependent on the volumetric mean free path of the CuAl2 particles and independent of minor variations in composition andheat-treatment. The creep stress was found to correlate with the creep rate-temperature parameter Z = ϵ˙seΔH/RT. Above ln Z = ln (ϵ˙seΔH/RT) = 46.0 and below ln Z = 27.5 the finer dispersions are superior, whereas over the intervening range of Z-values the coarser dispersions are superior. The energy for activation ΔH, was found to be a constant of about 37,000 cal per mol.
On the Drilling of Metals: 1—Basic Mechanics of the Process
Authors: Oxford C. J. 
Published: July 2022

Abstract
The cutting action of a twist drill is very complex. This paper describes an investigation of this complex phenomenon through use of a quick-stop technique to freeze the action. The formation of chips, both along the cutting edges and under the chisel edge, is considered. Chip-flow angles, measured experimentally, are related to effective rake angle along the cutting edges, using a new derivation of the normal rake angle for a twist drill. The effects of point angle, drill design, and workpiece material are considered. The split (crankshaft) point for heavy web drills is investigated and its operation described.
In-Plane Bending Properties of Welding Elbows
Authors: Vissat P. L. , Del Buono A. J. 
Published: July 2022

Abstract
This paper presents results of strain-gage investigations conducted on relatively heavy-wall “Weld-ELLS” having a ratio of bend radius to nominal pipe size of 1½:1. Also, several Weld-ELLS having a ratio of bend radius to nominal pipe size of 1:1 were tested. A comparison is made of the results against theory. Design factors for Weld-ELLS are established and tabulated.
Viscoelasticity of Polymethyl Methacrylate—an Experimental and Analytical Study
Authors: Knowles J. K. , Dietz A. G. H. 
Published: July 2022

Abstract
This paper is concerned (a) with a presentation of static tensile stress-strain data under many different experimental conditions on several types of methyl methacrylate, together with an empirical equation to describe them, and (b) with an attempt to correlate the static behavioral characteristics of two varieties of methacrylate by means of an extension of the Boltzmann-Volterra theory of the elastic aftereffect to an extent that facilitates the prediction of creep and constant-strain-rate curves from stress-relaxation data to within an error acceptable for engineering purposes.
Pulsating-Flow Measurement—A Literature Survey
Authors: Oppenheim A. K. , Chilton E. G. 
Published: July 2022

Abstract
Technical publications on the measurement of pulsating flow are reviewed. Fundamental aspects of the subject are stressed, and applications of pressure-differential meters are emphasized because of their importance to industry. Problems related to these meters are classified into those concerned with flow through the meter test section, the effect of the flow system on the meter, and the transmission of the signal from meter to recorder. Operation and application to pulsating flow of other meters such as the turbine type and electromagnetic flowmeter, the hot-wire anemometer, and the so-called “true mass-rate flowmeter” also are outlined. A summary of information available in codes and manuals is included.
Applying Bearing Theory to the Analysis and Design of Pad-Type Bearings
Authors: Raimondi A. A. , Boyd John 
Published: July 2022

Abstract
A review-type paper which presents charts and tables for the design and analysis of both fixed-pad and pivoted-pad thrust bearings. These data yield theoretical bearing-performance characteristics on the basis of what is generally regarded to be the most usable theory. Typical bearing design examples are included which illustrate the facility with which theoretical calculations can be made.
Experimental Boiler Studies of the Breakdown of Amines
Authors: Jacklin C. 
Published: July 2022

Abstract
A report of the results obtained when several types of amines were tested for breakdown to ammonia in an experimental boiler. Test pressures ranged from 250 to 2500 psi and temperatures from 400 to 1200 F. Test results indicate that morpholine, which has been used successfully at 1600 psi and 1000 F, also shows relatively good stability at 2500 psi and 1200 F.
The Thermal Barrier—Structures
Authors: Hoff N. J. 
Published: July 2022

Abstract
In the past few years the term “barrier” has become popular in aeronautics. Not so long ago we heard of the sonic barrier which in the minds of many laymen represented a solid wall of compressed air which would not let an airplane through at the speed of sound. More recently the expression “thermal barrier” has been coined to indicate that the heating effect of air will set a definite limit to the speed of aircraft that can never be surpassed. As far as the sonic barrier is concerned, events have shown that supersonic flight is well possible. As a matter of fact, bullets flew at supersonic speeds even during the last century, and if no law of nature prevented them from doing so, it was unreasonable to expect airplanes to be stopped by the sonic barrier. The author is convinced that in a similar manner the difficulties presented by the high temperatures accompanying flight at supersonic speeds will be overcome through research and development. Thus the thermal barrier is not a stone wall that will shatter all hopes of high supersonic flight.
High-Frequency Oscillations of a Flame Held by a Bluff Body
Authors: Kaskan W. E. , Noreen A. E. 
Published: July 2022

Abstract
Experimental data are presented on the occurrence of flame-sustained transverse oscillations in a 2 × 4-in. duct with a V-gutter flameholder. The flame-speed versus flow-velocity field of burner operation was divided into an oscillation region and a nonoscillation region. The boundary line between the two was approximately described by an equation of the formSuU1.6=const where Su is the laminar flame speed and U is the flow velocity. The oscillation was characterized by the formation of vortexes downstream of the flameholder tips. These vortices distorted the flame front in such a way as to provide the driving force for the oscillation.
The Influence of Tap-Drill Size and Length of Engagement Upon the Strength of Tapped Holes
Authors: Oxford C. J. , Cook J. A. 
Published: July 2022

Abstract
The influence of tap-drill size (minor diameter) upon the strength of threaded assemblies has been the subject of much speculation, analysis, and testing, but the results presented generally have been inconclusive or have not covered all of the many possible types of thread failure. This paper reports the results of a series of correlative tests and supporting analysis performed in an attempt to solve this problem. Failures can be of three types: Breakage of the external-thread member; stripping of the external thread; or stripping of the internal thread. The effect of drilled-hole oversize is examined and is found to be a significant variable in some cases. Formulas are developed which extend the experimental data to permit analysis of most practical thread-element combinations. For assemblies of usual proportions and materials, it is found that 60 per cent thread height is adequate.
A Theory of Fatigue-Damage Accumulation in Steel
Authors: Henry D. L. 
Published: July 2022

Abstract
At present, there is no theoretical method for predicting the change in the endurance limit of steel specimens subjected to various numbers of cycles of overstressing at different stress levels. The theoretical and most of the experimental work accomplished thus far has been concerned with studying the change in endurance life at some stress level resulting from the accumulation of various amounts of overstressing at other stress levels. It is the purpose of this paper to present a simple theoretical model for predicting the change in endurance limit resulting from the accumulation of overstressing cycles at moderate levels of overstress and for moderate degrees of fatigue damage. Review of the literature indicates that it is reasonable to assume that fatigue damage occurring prior to the formation of a visible crack is equivalent to an increase in a “stress-concentration factor” associated with the particular defect in the specimen which will form the fatigue nucleus. The application of simple notch-factor concepts and the use of an empirical formula for the S-N curve for steel resulted in an equation for predicting the change in the S-N curve when specimens are subjected to overstressing histories producing moderate amounts of fatigue damage.
Steam-Piping Design to Minimize Creep Concentrations
Authors: Robinson Ernest L. 
Published: July 2022

Abstract
Believing that steam-piping design for high-temperature service has heretofore been based largely upon elastic analysis of expansion stresses without adequate consideration of the importance of high-temperature creep, the author discusses the principles governing the relaxation of expansion stresses during service at high temperature and points out the possibility of creep concentrations in local spots of maximum stress. A number of specific examples are given to show that ordinary piping design usually can be made without such concentrations. Contrariwise, the type of expansion flexibility which invites excessive creep is illustrated. The desirability of cold springing pipe so as to minimize stress at high temperature is emphasized.
An Approximate Solution of Compressible Turbulent Boundary-Layer Development and Convective Heat Transfer in Convergent-Divergent Nozzles
Authors: Bartz D. R. 
Published: July 2022

Abstract
A method has been derived for computing the development of the velocity boundary layer, the temperature boundary layer, and the local convective heat transfer in convergent-divergent nozzles. The method is based on approximate solutions of the integral momentum and integral energy equations for compressible turbulent boundary layers. To obtain the solutions, a flow model is adopted for which are prescribed the velocity and temperature profiles in the boundary layer, the skin-friction law, and the relation between heat and momentum transfer. The local heat-transfer coefficient is expressed as an explicit function of the boundary-layer thicknesses. The effects of nozzle size and throat radius of curvature on boundary-layer development and heat transfer are determined for certain similar nozzle contours in common use. The results of the solution are demonstrated by a sample calculation for a conventional rocket nozzle operating under typical conditions. The computed local heat fluxes were found to be in approximate agreement with those measured during rocket-motor tests using a nozzle of the same contour.
Shear-Plane Temperature Distribution in Orthogonal Cutting
Authors: Weiner J. H. 
Published: July 2022

Abstract
An analytical solution is presented for the temperature distribution along the shear plane in orthogonal cutting. The principal assumption made is that the heat transferred by conduction in the direction of motion of the workpiece or chip may be neglected. The nature of the error involved in this assumption is investigated. The over-all fraction of shear-plane heat transferred into the workpiece is also computed and compared with previous results.
Transient Thermal Stresses in Circular Disks and Cylinders
Authors: Horvay G. 
Published: July 2022

Abstract
The effect of a suddenly applied peripheral temperature ϑ(R,φ,z,t)=Tcosnφ 1(t) upon circular disks and cylinders is considered. The most interesting results are (a) for thermal shock (t = very small) the stresses in an unrestrained cylinder are φφ︵∼zz︵∼-EαT1-μ(r/R)R/πκtcosnφ and all other stresses vanish; (b) in the steady state (t = ∞) the temperature distribution is ϑ(r,φ)=T(r/R)ncosnφ and all stresses vanish.
Dynamic Properties of Nodular Cast Iron: Part 2—Size Effect
Authors: Majors Harry 
Published: July 2022

Abstract
Rotating-beam endurance tests at room temperature have been conducted on 0.86-in-diam minimum notch sections and 1.25-in-diam minimum unnotched sections in order to compare fatigue data obtained from geometrically similar specimens having minimum diameters of 0.19 in. and 0.30 in., respectively. Comparisons have been made for tension-test data obtained from sections of 0.19 in., 0.50 in., and 0.75 in. diam. A series of exploratory tests in fatigue were made on grooved specimens and for two notch angles for comparison with results obtained on ungrooved specimens. Results are reported for the optimum chemical composition without any nickel content in the annealed and as-cast condition.
A Summary of NACA Research on Heat Transfer and Friction for Air Flowing Through Tube With Large Temperature Difference
Authors: Pinkel Benjamin 
Published: July 2022

Abstract
The results of experimental and analytical studies performed at the NACA to determine the heat-transfer and friction coefficients for the flow of air through tubes with large difference in temperature between tube wall and air, (a) for smooth tubes of circular cross section; (b) for tubes of noncircular cross-sectional shapes; and (c) for tubes with various degrees of surface roughness, are summarized. The experiments for the smooth tubes of circular cross section cover a range of tube-wall temperature from 535 R to 3050 R, inlet-air temperature from 535 R to 1500 R, Reynolds numbers from 1000 to 500,000, exit Mach numbers up to 1, and tube length-to-diameter ratios from 15 to 120. Methods of correlating these data are discussed. The tubes of noncircular cross-sectional shape, namely, (a) square, (b) rectangular, and (c) triangular, were investigated at tube wall-to-air temperature differences up to 1200 F and Reynolds numbers between 2500 and 250,000. Three degrees of surface roughness, obtained by machining square threads into the inner surface of the tube, were investigated for temperature differences between the air and tube wall up to 1500 F and Reynolds numbers from 1000 to 350,000.
Application of Quality-Control Requirements in Manufacture of Components for a Coaxial-Carrier System
Authors: Chapman A. T. 
Published: July 2022

Abstract
Economic solution of transmission problems in a new coaxial-carrier system required limitation of excursions of sensitive characteristics from the design center. Basic quality-control techniques were utilized in developing a pattern of distribution requirements for the key characteristics of the critical electronic components. A description of the statistical techniques is presented with several illustrative factory applications.
Experimental Superheater for Steam at 2000 Psi and 1250 F—Progress Report After 12,000 Hours of Operation
Authors: Eberle F. , Ely F. G. , Dillon J. A. 
Published: July 2022

Abstract
In order to supplement laboratory studies on certain new alloys developed in the past few years, a test element was constructed and installed in an operating boiler at the Twin Branch plant. Operation, which is similar to a small superheater, was started in March 1950. Experience with the unit for the first two years was described in a previous paper. The present paper gives the record for the past two-year period and includes preliminary information derived from metallurgical examination of specimens removed from the element after nearly 7000 hr of operation.
Design and Operation of High-Recovery Regenerative-Type Air Preheaters: Part 1—Special Features of the Regenerative-Type Air Preheaters
Authors: Braddon George 
Published: July 2022

Abstract
Air preheating has become the most widely accepted method of recovering heat from flue gases of high-efficiency steam-generating units. The drive to reduce stack losses further and improve over-all efficiencies continues. The regenerative air preheater possesses unique characteristics which contribute to its ability to achieve maximum reduction in stack losses while permitting continuous operation over long periods. This paper deals with those features of the regenerative air preheater which are inherent in the type and are created expressly for the purpose of realizing high efficiency coexistent with high availability.
A Study of the Effects of Cyclic Thermal Stresses on a Ductile Metal
Authors: Coffin L. F. 
Published: July 2022

Abstract
The results of a study of cyclic strain and fatigue failure arising from cyclic thermal stresses are reported. By means of a test apparatus described in a companion paper, a cyclic temperature is imposed on a thin tubular test specimen subjected to complete longitudinal constraint. Hence, the cyclic strain is the independent variable. The following studies are reported: (a) Effect of thermal-stress cycling on strain hardening and life-to-failure for a fixed mean temperature, (b) effect of degree and kind of previous cold work on strain hardening and cycles-to-failure, (c) effect of mean temperature on thermal-stress cycling, (d) effect of period of cycle on cycles-to-failure, and (e) effect of prior strain cycling on stress-strain characteristics. The significance of factors such as hysteresis, Bauschinger effect, strain hardening, strain aging, and fatigue-crack formation is discussed, and a mechanism is described to relate these factors. Evidence is presented to show that strain hardening is not an important factor in the problem. The concept of total plastic strain is discussed.
Theoretical Calculation of the Equation of State and Transport Properties of Gases and Liquids
Authors: Bird R. B. , Hirschfelder J. O. , Curtiss C. F. 
Published: July 2022

Abstract
Several years ago a summary article was written (1) about the theoretical calculation of the viscosity and several other properties of gases and gas mixtures. Since that time further calculations of the equation of state and transport coefficients of dense gases and liquids have been made. Although the statistical mechanical theory is an involved and highly mathematical topic, and although some of the numerical computations are quite complex, the final results, nevertheless, may be presented in terms of tabulated functions, which are easy to use in practical calculations. The formulas and tables given in this paper should prove useful in engineering-design calculations and in chemical-process studies. Furthermore, the underlying statistical mechanical theory whenever possible should be used to give intelligent interpretation to the analysis and correlation of chemical and engineering data on the properties of matter.
Generalized pvT Properties of Gases
Authors: Nelson L. C. , Obert E. F. 
Published: July 2022

Abstract
In this paper two sets of generalized compressibility charts are presented: One set is based upon critical temperatures and pressures as in the past; the other set is based upon pseudo-reduced co-ordinates obtainable from the Lennard-Jones force potential. In both sets the underlying data are more extensive than those used in constructing older charts since a complete survey of existing pvT data was made. The results of this survey for 30 gases are contained in a Bibliography of 275 items which has been constructed to show the extent of the experimental data by including the ranges of pressure and temperature for each item. Although the charts are intended for engineering computations, the chart for the low-pressure region (pr = 0 to 1), for example, has a deviation of 1 per cent for 26 gases.
Dynamic Characteristics of Silicone Rubber
Authors: Painter G. W. 
Published: July 2022

Abstract
The unusual high and low-temperature properties of silicone rubber have made it a desirable material for vibration isolators designed for service at temperature extremes. In general, silicone cannot be substituted directly for such elastomers as natural rubber and neoprene in established designs. This lack of interchangeability results principally from the lower tensile strength and the unusual load-deflection characteristics of the material. A program to investigate the dynamic properties of silicone rubber was undertaken to provide the design engineer with information which would allow the material to be utilized properly. This paper deals with the viscoelastic properties of silicone rubber under various conditions of strain, frequency, and temperature. Where possible, comparisons are made with natural rubber.
The Utility of Mixed Models in Sport Science: A Call for Further Adoption in Longitudinal Data Sets
Authors: Newans Tim , Bellinger Phillip , Drovandi Christopher , Buxton Simon , Minahan Clare 
Published: July 2022

Purpose: Sport-science research consistently contains repeated measures and imbalanced data sets. This study calls for further adoption of mixed models when analyzing longitudinal sport-science data sets. Mixed models were used to understand whether the level of competition affected the intensity of women’s rugby league match play. Methods: A total of 472 observations were used to compare the mean speed of female rugby league athletes recorded during club-, state-, and international-level competition. As athletes featured in all 3 levels of competition and there were multiple matches within each competition (ie, repeated measures), the authors demonstrated that mixed models are the appropriate statistical approach for these data. Results: The authors determined that if a repeated-measures analysis of variance (ANOVA) were used for the statistical analysis in the present study, at least 48.7% of the data would have been omitted to meet ANOVA assumptions. Using a mixed model, the authors determined that mean speed recorded during Trans-Tasman Test matches was 73.4 m·min−1, while the mean speeds for National Rugby League Women and State of Origin matches were 77.6 and 81.6 m·min−1, respectively. Random effects of team, athlete, and match all accounted for variations in mean speed, which otherwise could have concealed the main effects of position and level of competition had less flexible ANOVAs been used. Conclusion: These data clearly demonstrate the appropriateness of applying mixed models to typical data sets acquired in the professional sport setting. Mixed models should be more readily used within sport science, especially in observational, longitudinal data sets such as movement pattern analyses.