bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimum Stresses of Structural Elements at Elevated Temperatures
Authors: Schnitt Arthur , Brull M. A. , Wolko H. S. 
Published: February 2022

Abstract
A method is developed by which optimum-stress curves for a given material at any temperature may be calculated from the room-temperature optimum-stress curves for a different material. The only data required to perform this transformation are stress-strain curves of both materials. As examples, optimum-stress envelopes are obtained for wide columns and multiweb beams over a wide range of temperatures. Relations are developed between the properties of optimized elements of different materials so that the detailed dimensions of any element may be calculated by considering a properly selected equivalent aluminum element. An approximate procedure is developed for the determination of maximum life when creep is significant. The method is then extended so as to permit comparison of unprotected structures with insulated and cooled structures, on the basis of minimum weight-strength and as a function of temperature and exposure time. Thus these developments lead to a systematic procedure by which the optimum structural arrangement and material may be selected for a given loading and known thermal environment.
Some Structural Penalties Associated With Thermal Flight
Authors: Mar J. W. , Schmit L. A. 
Published: February 2022

Abstract
In designing aircraft for high-speed flight, the structural designer is confronted by many factors which tend to increase the weight. As Prof. R. L. Bisplinghoff points out, the static strength of the structure still appears to be the most important design requirement for high-speed, manned, fighter-type aircraft of the foreseeable future. In subsonic aircraft, the margin of static strength is measured by comparing the stresses caused by maneuvering with the permissible stresses which the material can carry. In high-speed supersonic aircraft, the static strength must take into account not only the thermal stresses but also the degradation in the mechanical properties of the material which accompany elevated temperatures. This paper investigates the short-time static strength of the structure as it is subjected to the combined action of maneuvering loads and internal heat flow.
Effect of the Volute on Performance of a Centrifugal-Pump Impeller
Authors: Bowerman R. D. , Acosta A. J. 
Published: February 2022

Abstract
An experimental study of volute influence on radial flow-impeller performance was conducted by operating a single impeller with three different sets of volute vanes. In each case, over-all performance was measured and an internal-flow study within the volute was made. The results show that at their respective design flow rates the influence of the volutes is least and the deviation of performance from the free-impeller operation is small. At off-design flow rates there are major changes in the impeller performance resulting from the presence of the volutes. Large real fluid effects, coupled with a nonuniform velocity pattern at the impeller exit, result in a flow through the volute that does not resemble a potential flow. Even so, the fluid losses through the volute are comparatively small.
Mollier Diagrams for Water Near Bubble Point
Authors: Van Haute André , Sage B. H. 
Published: February 2022

Abstract
In many problems of engineering interest a knowledge of the thermodynamic properties of water in the heterogeneous region near bubble point is of value. A series of Mollier diagrams for water at states from bubble point to a quality of 0.05 was prepared and similar diagrams relating to the behavior of the condensed liquid were included. The Mollier diagram was employed because of its utility in connection with graphical operations of a thermodynamic nature pertaining to the flow of homogeneous and heterogeneous fluids near bubble point. An example of the application of the diagrams to the solution of the simple problem of flow in short tubes was included.
Statistical Analysis of a Wear Process
Authors: Rightmire B. G. 
Published: February 2022

Abstract
An expression for metal transfer during a wear process studied experimentally by Kerridge (5) is formulated in terms of the statistical behavior of the sliding contacts. The results lend quantitative support to the view that oxidation of the contacts plays a critical role in determining the metal transfer and wear. Based on this formulation, new experiments are suggested and the anticipated results for two cases are discussed.
Testing Dynamically Loaded Bearings—I: A Short History of Bearing Test Machines
Authors: Hersey M. D. , Snapp R. B. 
Published: February 2022

Abstract
Bearing test machines with dynamic loading or nonuniform motion are described in this paper and classified according to the type of loading employed. Over thirty such machines have been disclosed in the published literature, including both endurance machines and research machines for investigating oil-film performance. The authors have endeavored to find answers to six questions concerning each machine—(a) its loading mechanism, (b) test bearing details, (c) range of variables, (d) performance criteria, (e) characteristic limitations or advantages, and (f) extent of use.
A Comparison of Hydraulic and Pneumatic Accessory Power Generation
Authors: Brown E. I. 
Published: February 2022

Abstract
Aircraft accessory-power transmission systems utilizing hydraulic pumps and motors are shown to be more efficient than those using pneumatic turbines driven by compressor bleed. The hydraulic system shows significant advantages in terms of both engine maximum thrust and cruise fuel consumption. A convertible hydraulic unit used as a turbojet starter motor and as an engine-driven hydraulic pump offers weight and performance advantages which further increase the value of hydraulics for all aircraft accessory-power systems.
Effects of Complex Stress-Time Cycles on the Fatigue Properties of Metals
Authors: Starkey W. L. , Marco S. M. 
Published: February 2022

Abstract
An investigation was conducted to determine the effects of complex stress-time cycles on the fatigue properties of metals. The uniaxial stresses studied were complex in the sense that their stress-time patterns may be analyzed as composed of several harmonic components. Four theoretical design methods, and the results of an experimental investigation involving complex stresses are presented. Comparisons are made of the test results with the theory predictions.
Fatigue of Metals Under Combinations of Stresses
Authors: Findley W. N. 
Published: February 2022

Abstract
Analysis of available information suggests that the phenomenon of fatigue of materials results primarily from alternating shearing stress producing cracks along shear planes, and that the resistance to fatigue cracking is influenced by other factors. Some of these factors are changes in structure of the material resulting from plastic and elastic stressing as well as heat-treatment; the mode of crack propagation and the complementary normal stress on planes of shear stress. Several theories of failure under combined stress are examined and modified to account for observed facts. A general design expression is proposed. The influence of mean stress (including extreme compression), yielding, complementary normal stress, and anisotropy are considered.
Metallurgical Considerations of Main Steam Piping for High-Temperature, High-Pressure Service
Authors: Blumberg H. S. 
Published: February 2022

Abstract
The paper presents a broad approach to the selection and behavior aspects of materials for modern high-temperature, high-pressure, steam power-plant piping. The author summarizes the steels currently used and analyzes the possibilities of superstrength alloys for high-temperature steam piping. He also presents a progress report of a program for selecting materials for the Eddystone Unit of the Philadelphia Electric Company (1200 F, 5600 psi design conditions).
Two Applications of a Digital Computer to Machine-Design Problems
Authors: Lester Joseph T. 
Published: February 2022

Abstract
Two examples are presented that illustrate two types of problems wherein a high-speed computer can provide important aid to the design engineer: (a) Tedious table-making computations; (b) solution of complex differential equations. The two applications represented are, respectively, a cycloidal crank-drive mechanism and a swing-type hammer mill.
Heat Transfer to Lead-Bismuth in Turbulent Flow in an Annulus
Authors: Seban R. A. , Casey D. F. 
Published: February 2022

Abstract
Heat-transfer coefficients for molten lead-bismuth eutectic are presented for flow in annuli externally heated at a constant rate. Diameter ratios of 1.30 and 1.74 were investigated and results were obtained for Peclet numbers from 400 to 1600. These results are shown to be related to analogy predictions for this system in the same manner as exists for pipe flow, and that the theories providing a rationalization of the results for pipe flow do so as well for the flow in an annulus.
Design of Supersonic Expansion Nozzles and Calculation of Isentropic Exponent for Chemically Reacting Gases
Authors: Edse R. 
Published: February 2022

Abstract
For the calculation of sonic velocities or changes in pressure, volume, or temperature in gases, the isentropic or polytropic exponent of the gas or gas mixture must be known. So far it has been needed also for designing supersonic expansion nozzles. However, it is shown in this paper that more accurate designs of such nozzles can be obtained without the use of the isentropic or polytropic exponent. As long as no chemical reaction occurs in the gas, the isentropic exponent is equal to the ratio of the specific heat at constant pressure to that at constant volume. However, in jet engines or in hypersonic wind tunnels using very high stagnation temperatures, the isentropic exponent is no longer identical to the ratio of the specific heats because of the energy released or absorbed by the chemical reactions. Methods are presented for calculating differential and integral values of the isentropic exponents in gases without and with consideration of chemical reactions. A numerical evaluation of the method is given for dissociating hydrogen. The results of this investigation indicate that the isentropic exponent of a chemically reacting gas mixture differs greatly from the ratio of the specific heats. It is also shown that accurate designs of supersonic expansion nozzles for chemically reacting gases require a detailed thermodynamic analysis of the system.
Apparent Frictional Forces on Clamping Elements as Used in the Oil Industry
Authors: Moser E. I. , Wilhoit J. C. 
Published: February 2022

Abstract
This study endeavors to show a method whereby the clamping effect of such tools as drill-pipe slips, casing slips, and so forth, may be determined analytically. This subject is of interest in view of the fact that serrations on the faces of such clamping elements are often suspected of producing focal points of failure. It is shown that the individual teeth of the serration need not be of the conventional “saw-tooth” or “sharp-wedge” variety. The apparent frictional forces for penetrators having round tips were found to be worth considering for clamping elements.
Importance of Matching Steam Temperatures With Metal Temperatures During Starting of Large Steam Turbines
Authors: Jackson R. L. , Coulter S. B. , Sheppard R. 
Published: February 2022

Abstract
The best kind of operation for a steam turbine is to keep it continuously under constant load at constant steam pressure and temperature. However, system-load variations and present-day requirements call for daily starting and stopping of some units. Usually this type of operation has fallen on the older units built for lower pressures and temperatures than are common for new units today. The industry is reaching the point where the turbines subjected to this service are of the 1250-psig 950-F or even 1450-psig 1000-F level. This practice has proved to be the cause of some shell cracking. As a result, studies have been made to determine the factors occurring during the start-up period which produce cracking and what can be done to prevent trouble of this kind in the future.
Instrumenting a Field Study of Industrial Water-Cooling Tower Performance
Authors: Willa J. L. ,   Technical Sub-Committee No. 2 of the Cooling Tower Institute
Published: February 2022

Abstract
In pursuit of its objective “to advance the technology, design, and performance of industrial cooling towers,” the Cooling Tower Institute undertook a comprehensive investigation of the several factors influencing tower performance. In the hope of developing either corrections or compensations for the loss of capacity due to changes in atmospheric conditions, including wind velocity and direction, a thorough study was made to determine the exact cause and magnitude of the losses on various sizes, types, and configurations of water-cooling towers.
Heat Transfer by Radiation From Flames: A Summary of the Work of the International Flame Research Foundation
Authors: Sherman R. A. 
Published: February 2022

Abstract
A unique example of international co-operation is given in the program of research on radiation from flames in industrial furnaces that is being conducted at the Royal Netherlands Blast Furnace and Steel Works. Financial support and direction came first from the Netherlands, France, and Great Britain. These countries have now been joined by Belgium, Sweden, the United States, and the High Authority of the European Community of Coal and Steel. This paper outlines the organization of the work, the experimental facilities, the methods of research, and presents the outstanding results on the effect of the variables studied on flame radiation. These variables have been the type of fuel oils or coke-oven gas, the rate of heat input, the type and rate of supply of atomizing agent, the type of burner, the excess of air, the type and amount of carbureting agent for gas, and the temperature of the combustion air. Of these several variables, the C/H ratio of the oil and gas fuels and the mixing conditions most markedly affect the emissivity and the radiation of the flames. The results point to the need for further knowledge of the relation of the radiating characteristics of flames to the rate of heat transfer to “work” in furnaces. The research has now been extended to include the use of pulverized coal.
Resistance Coefficients for Laminar and Turbulent Flow Through One-Half-Inch Valves and Fittings
Authors: Kittredge C. P. , Rowley D. S. 
Published: February 2022

Abstract
Apparatus and test procedures to determine resistance coefficients for laminar and turbulent flow through ½-in. I.P.S. valves, fittings, and fabricated bends are described. Resistance coefficients are given as functions of Reynolds number. Results of the investigation are discussed briefly.
Responses of Temperature-Sensing-Element Analogs
Authors: Coon G. A. 
Published: February 2022

Abstract
From the standpoint of stability, temperature-sensing elements used in control systems should not contribute much phase lag at the frequency where the open-loop phase lag is 180 deg. For those cases where the temperature-sensing element does not contribute appreciable (less than 30 deg) phase lag around 180 deg, it would be advantageous to have a low-frequency approximation which works for complicated thermal systems. This paper presents such an approximation and establishes its validity for the electrical analogs of many sensing elements. In addition, it shows how the approximation is related to the thermal lag measured during a ramp input and the 63 per cent response time. These results, which are obtained in terms of transfer functions, can be applied to other systems having the same analogs.
Signal Stabilization of a Control System
Authors: Oldenburger Rufus 
Published: February 2022

Abstract
Linear automatically controlled systems with two or more dominant lags may be stabilized by the introduction of noise, or a signal of sufficiently high frequency, or a signal with sufficiently high-frequency components, provided that the hunt of the system is not excessively severe. The amplitude of the signal must be enough to run a bounded element, such as a governor pilot valve, through its full stroke. One or multiple-lag systems with optimum nonlinear controls also may be stabilized by an appropriate signal. Unless the stabilizing signal is great the response to the larger disturbances will be affected negligibly.
Influence of Repeated Bending Loads on Biaxial Residual Stresses in Shot-Peened Plates
Authors: Elsesser T. M. 
Published: February 2022

Abstract
The futility of shot-peening certain members to increase their fatigue strength may be explained by the reduction of the initial residual stresses with increased numbers of repeated loads. The purpose of this investigation was to determine the changes in the biaxial residual stresses, induced by shot-peening, in steel plates subjected to cyclic bending loads. The plates were sectioned by etching, and curvature measurements were made to evaluate the residual-stress distributions in the region of the peened surface. The residual stresses were found to “fade” or decrease to at least 50 per cent of their initial value in 10,200 load cycles in the medium-hard (SAE 4340) steel investigated.
Analysis of a Process-Fluid-Flow Network by Electrical Analogy
Authors: Kayan C. F. , Balmford J. A. 
Published: February 2022

Abstract
In a process-fluid-flow network of numerous interconnected branches of different proportions, the determination of the flow distribution by calculation is difficult because of the pressure-drop versus flow-rate characteristics of each individual component of the complex. Not only does the pressure drop vary with the effective pipe dimensions and surface condition, for a given fluid, but also markedly with the flow rate, and usually, in turbulent flow, with flow rate modified by some exponent with value on the order of 2.0. The concept of flow “resistance,” to represent opposition to fluid flow, is a useful tool. The pressure drop in any process branch line may be considered as proportional to the product of the flow rate and the pipeline resistance, and for turbulent flow the resistance itself may be considered a function of the flow rate. Thus the flow characteristics of a network may be simulated by electrical analogy, with the electrical resistance in each branch simultaneously adjusted to some desired function of the electrical current. Voltage and current determinations at given points are representative of the corresponding fluid pressure and flow rates. An illustrative process-plant network with numerous branches and discharge points is analyzed, with predictions of flow distributions and pressures.
Association between thermal responses, medical events, performance, heat acclimation and health status in male and female elite athletes during the 2019 Doha World Athletics Championships
Authors: Racinais Sebastien , Havenith George , Aylwin Polly , Ihsan Mohammed , Taylor Lee , Adami Paolo Emilio , Adamuz Maria-Carmen , Alhammoud Marine , Alonso Juan Manuel , Bouscaren Nicolas , Buitrago Sebastian , Cardinale Marco , van Dyk Nicol , Esh Chris J , Gomez-Ezeiza Josu , Garrandes Frederic , Holtzhausen Louis , Labidi Mariem , Lange Gűnter , Lloyd Alexander , Moussay Sebastien , Mtibaa Khouloud , Townsend Nathan , Wilson Mathew G , Bermon Stephane 
Published: February 2022

PurposeTo determine associations between thermal responses, medical events, performance, heat acclimation and health status during a World Athletics Championships in hot-humid conditions.MethodsFrom 305 marathon and race-walk starters, 83 completed a preparticipation questionnaire on health and acclimation. Core (Tcore; ingestible pill) and skin (Tskin; thermal camera) temperatures were measured in-competition in 56 and 107 athletes, respectively. 70 in-race medical events were analysed retrospectively. Performance (% personal best) and did not finish (DNF) were extracted from official results.ResultsPeak Tcoreduring competition reached 39.6°C±0.6°C (maximum 41.1°C). Tskindecreased from 32.2°C±1.3°C to 31.0°C±1.4°C during the races (p<0.001). Tcorewas not related to DNF (25% of starters) or medical events (p≥0.150), whereas Tskin, Tskinrate of decrease and Tcore-to-Tskingradient were (p≤0.029). A third of the athletes reported symptoms in the 10 days preceding the event, mainly insomnia, diarrhoea and stomach pain, with diarrhoea (9% of athletes) increasing the risk of in-race medical events (71% vs 17%, p<0.001). Athletes (63%) who performed 5–30 days heat acclimation before the competition: ranked better (18±13 vs 28±13, p=0.009), displayed a lower peak Tcore(39.4°C±0.4°C vs 39.8°C±0.7°C, p=0.044) and larger in-race decrease in Tskin(−1.4°C±1.0°C vs −0.9°C±1.2°C, p=0.060), than non-acclimated athletes. Although not significant, they also showed lower DNF (19% vs 30%, p=0.273) and medical events (19% vs 32%, p=0.179).ConclusionTskin, Tskinrate of decrease and Tcore-to-Tskingradient were important indicators of heat tolerance. While heat-acclimated athletes ranked better, recent diarrhoea represented a significant risk factor for DNF and in-race medical events.
Prevalence and predictors of medication non-adherence among people living with multimorbidity: a systematic review and meta-analysis
Authors: Foley Louise , Larkin James , Lombard-Vance Richard , Murphy Andrew W , Hynes Lisa , Galvin Emer , Molloy Gerard J 
Published: February 2022

ObjectivesThis systematic review aimed to describe medication non-adherence among people living with multimorbidity according to the current literature, and synthesise predictors of non-adherence in this population.MethodsA systematic review was conducted according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses. PubMed, EMBASE, CINAHL and PsycINFO were searched for relevant articles published in English language between January 2009 and April 2019. Quantitative studies reporting medication non-adherence and/or predictors of non-adherence among people with two or more chronic conditions were included in the review. A meta-analysis was conducted with a subgroup of studies that used an inclusive definition of multimorbidity to recruit participants, rather than seeking people with specific conditions. Remaining studies reporting prevalence and predictors of non-adherence were narratively synthesised.ResultsThe database search produced 10 998 records and a further 75 were identified through other sources. Following full-text screening, 178 studies were included in the review. The range of reported non-adherence differed by measurement method, at 76.5% for self-report, 69.4% for pharmacy data, and 44.1% for electronic monitoring. A meta-analysis was conducted with eight studies (n=8949) that used an inclusive definition of multimorbidity to recruit participants. The pooled prevalence of non-adherence was 42.6% (95% CI: 34.0 - 51.3%,k=8,I2=97%,p<0.01). The overall range of non-adherence was 7.0%–83.5%. Frequently reported correlates of non-adherence included previous non-adherence and treatment-related beliefs.ConclusionsThe review identified a heterogeneous literature in terms of conditions studied, and definitions and measures of non-adherence used. Results suggest that future attempts to improve adherence among people with multimorbidity should determine for which conditions individuals require most support. The variable levels of medication non-adherence highlight the need for more attention to be paid by healthcare providers to the impact of multimorbidity on chronic disease self-management.PROSPERO registration numberCRD42019133849.