bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Statistical Theory of Size and Shape Effects in Fatigue
Authors: McClintock F. A. 
Published: June 2021

Abstract
Fatigue specimens are considered in which the stress amplitude is constant with respect to time but falls off parabolically along the length of the specimen from the point of maximum stress. From assumptions regarding the local variability in the strength of the material, equations are derived relating the scatter in cycles to failure to the scatter in position of failure. The effect of specimen size is determined for these two types of scatter, as well as for the average life. It is found that the shape of the distribution function does not affect seriously the relation between scatter in cycles to failure and scatter in position of failure. The size effect, however, is markedly influenced by the shape of the distribution function. A modification is suggested to make the results applicable to tests to determine the endurance limit, where the stress amplitude is a variable.
Large Deflection Analysis for a Plate Strip Subjected to Normal Pressure and Heating
Authors: Williams M. L. 
Published: June 2021

Abstract
Large deflection analysis is carried out to determine the deflections and membrane stresses for an infinite strip when subjected to pressure and temperature variations across the width of the strip with the end points fixed in space. Results are graphed for both clamped and simply supported edge conditions in the case of uniform temperature T0, and uniform pressure p0. The calculations also include the possible thermal buckling deflections. In the limit case of a membrane of width b and thickness h, subjected to this loading condition, the central deflection w0 is determined from the simple relation [ ( w 0 / h ) 2 - 3 8 ( 1 + ν ) ( b / h ) 2 α T 0 ] ( w 0 / h ) = p 0 b 4 / ( 256 D h )
Aerodynamic Interference of Cascade Blades in Synchronized Oscillation
Authors: Chang Chieh-Chien , Chu Wen-Hwa 
Published: June 2021

Abstract
The failure of a compressor is sometimes due to flutter of the blades. Essentially, this problem is equivalent to a cascade in oscillation. The present analysis is to find the aerodynamic load on cascade in synchronized harmonic oscillations, pitching, and flapping. Conformal mapping is used. Two characteristic parameters are involved in the force and moment. One is μ which is related to the gap-chord ratio. The other is k which is known as reduced frequency. The main results are expressed in terms of these two parameters. Most can be reduced to closed form. The rest are given in graphs. The wake interference involves one new function C(μ,k) which is related to a ratio of two hypergeometric functions and which reduces to Theodorsen’s function C(k) in the limit of infinite gap. In a certain range of frequency and gap-chord ratio, the analysis shows quantitatively that single-oscillation airfoil theory may lead to inaccurate estimation of interference effect between blades.
Thin Circular Conical Shells Under Arbitrary Loads
Authors: Hoff N. J. 
Published: June 2021

Abstract
Equations defining the displacements of the median surface of a conical shell under arbitrary loads are developed. In their derivation only the essential parts of the strain energy are considered and three simultaneous partial differential equations are obtained through the use of the variational calculus. When the minimum radius of curvature of the median surface of the cone is made to approach a constant value, the cone goes over into a cylinder. At the same time the equations here developed for the cone are transformed into the Donnell equations of the theory of cylindrical shells. It is shown how eigenfunctions of the homogeneous equations can be constructed and how particular solutions can be found for any arbitrary loading.
Bending Creep and Its Application to Beam-Columns
Authors: Hu L. W. , Triner N. H. 
Published: June 2021

Abstract
A procedure for evaluating the creep deflection of members subjected to bending moment is suggested. The application of the suggested procedure to beam-columns is given. For checking the validity of the proposed method, an investigation on the creep behavior of beam-columns of magnesium alloy FS1-F at 260 F was conducted. The comparison of the experimental results with the theoretical predictions was found satisfactory.
Effect of an Acoustic Medium on the Dynamic Buckling of Plates
Authors: DiMaggio F. L. 
Published: June 2021

Abstract
The effect of a surrounding fluid on the dynamic buckling of an elastic plate under suddenly applied compressive stresses in its middle plane is studied. Assuming an infinite plate supported at regular intervals and a semi-infinite acoustic medium, exact and approximate solutions are obtained. By a numerical example, it is shown that for steel plates in water, with dimensions usually encountered in ship structures, the compressibility of water can be neglected.
A Theory of the Yield Point and the Transition Temperature of Mild Steel
Authors: Forscher F. 
Published: June 2021

Abstract
Experimental results indicate the dependence of the yield-point phenomenon of mild steel on temperature, strain rate, duration of stress, and stress state. This paper proposes a yield criterion which can account for these variables. The theory is developed on the basis of a “structural” model, by which the behavior of microscopic and submicroscopic elements is idealized. The theory postulates as yield criterion a critical number of relaxation centers (active Frank-Read sources) or, equivalently, a critical size of relaxation centers. The transition-temperature phenomenon is considered to be the result of an inhibition of yielding (upper yield point) by means of geometry, temperature and/or strain rate. A relation is given which expresses its dependence on the state of stress and strain rate.
A Method of Stepwise Integration in Problems of Impact Buckling
Authors: Schmitt A. F. 
Published: June 2021

Abstract
The equations for the dynamic buckling of an axially impacted column are discussed. A method is presented for the calculation of approximate load and deflection variations in problems of high-velocity impact. The method may be extended for cases wherein the stresses exceed the elastic limit. Results of calculations are presented for two cases. In one of these, agreement with a previous exact solution is found to be good.
Wave Propagation in an Elastic Rod Exhibiting Internal Coulomb Friction, Considered as a Model for a Ring Spring
Authors: Lee E. H. , Wang A. J. 
Published: June 2021

Abstract
The problem of stress-wave propagation in a ring spring is considered. A ring spring consists of rings placed normal to the spring axis with alternate internal and external conical bearing surfaces. The friction between these surfaces causes a loading-unloading relation which is strongly irreversible, leading to marked energy absorption for oscillatory stressing. The attenuation of a pulse of stress is analyzed in detail as it is propagated down a spring of infinite length. The influence of certain spring characteristics is evaluated. Concentration of the absorption of the total input energy is found in the region of the impact end of the spring, and particular examples are presented.
Studies on Plastic Flow of Anisotropic Metals
Authors: Hu L. W. 
Published: June 2021

Abstract
This investigation deals with a study of the plastic behavior of anisotropic metals. By extending Hill’s theory of plastic flow of anisotropic metals, plastic stress-strain relations for anisotropic materials with strain hardening are developed. Applications of these relations are also made to plane-stress and plane-strain problems with anisotropy. The effect of anisotropy on the stress distribution and on the pressure to produce yielding in a thick-walled cylinder under internal pressure is discussed. The influence of anisotropy on the interpretation of conventional biaxial tension-tension and tension-torsion tests is also considered in this study.
Rational Analysis of Heat-Exchanger Tube-Sheet Stresses
Authors: Yu Yi-Yuan 
Published: June 2021

Abstract
The paper presents a rational method of analysis of heat-exchanger tube-sheet stresses. While the tube sheet is taken to be a perforated plate on an elastic foundation in the manner of Gardner and Miller, it is also considered as part of an integrated indeterminate structure, and the interaction between the tube sheet and the connecting cylindrical shells and flange of the exchanger is determined so that a condition may be formulated which the edge rotation and edge moment of the tube sheet must satisfy. In general, neither the edge rotation nor the edge moment is zero; the edge of a tube sheet is therefore neither clamped nor simply supported. Application of the present method to four different types of heat exchangers is described in detail. To illustrate the method, Gardner’s example of a fixed-tube-sheet exchanger is recalculated. While Gardner’s method yields only the two limiting values of the maximum stress in the tube sheet, which differ by more than 100 per cent, the present method makes it possible to determine the exact value of this maximum stress. By means of the present method, the stresses in the other parts of the heat exchanger, namely, the tubes, shell, head, and flange, also can be calculated. As a consequence of the present analysis, it is found that, in the external-floating-head type of exchanger, the tube-sheet stress is not independent of the shell-side pressure, which is contrary to Gardner’s and Miller’s conclusions.
The Mathematical Analysis of Bow Girders of Any Shape
Authors: Abbassi M. M. 
Published: June 2021

Abstract
By using parametric equations in which the parameter is the angle included between the tangent at any point on the bow girder and the tangent at the middle point, the analysis of bow girders of shapes other than the circular arc can be treated mathematically. Exact and approximate formulas are given for symmetrical bow girders of any shape carrying a distributed load or two equal concentrated loads placed symmetrically with respect to the middle point of the girder.
On the Stresses in a Strip Under Tension and Containing Two Equal Circular Holes Placed Longitudinally
Authors: Atsumi A. 
Published: June 2021

Abstract
A problem of determining the stresses in an infinite strip of finite breadth under tension and containing two equal circular holes placed on the longitudinal axis is studied theoretically. Stresses are calculated by a perturbation method, in each case the radius of the circle and the distance between the centers of two holes being varied. From consideration of the results obtained, some conclusions are made regarding the effects of the straight boundaries and the holes.
On the Torsional Oscillations of a Solid Sphere in a Viscous Fluid
Authors: Carrier G. F. , Di Prima R. C. 
Published: June 2021

Abstract
Most treatments of the torsional oscillations of solid bodies assume that the velocity field is circumferential. In this paper the motion in planes containing the axis of oscillation is also considered. An expansion in terms of the angular displacement ϵ (assumed small) is made. The first approximation to the circumferential velocity is computed, and then used in computing the first approximation to the pumping motion. This is used to compute the correction to the circumferential velocity and, in particular, the correction to the viscous torque. For the range of parameters considered it is found that the correction to the torque is of the order of 0.04ϵ2|N0|, where N0 is the classical viscous torque. This problem is of interest in practical viscosity measurements.
Early Dynamics of a Laser-Induced Underwater Shock Wave
Authors: Lai Guihua , Geng Siyuan , Zheng Hanwen , Yao Zhifeng , Zhong Qiang , Wang Fujun 
Published: June 2021

Abstract
The objective of this paper is to observe and investigate the early evolution of the shock wave, induced by a nanosecond pulsed laser in still water. A numerical method is performed to calculate the propagation of the shock wave within 1 μs, after optical breakdown, based on the Gilmore model and the Kirkwood–Bethe hypothesis. The input parameters of the numerical method include the laser pulse duration, the size of the plasma, and the maximally extended cavitation bubble, which are measured utilizing a high time-resolved shadowgraph system. The calculation results are verified by shock wave observation experiments at the cavitation bubble expansion stage. The relative errors of the radiuses and the velocity of the shock wave front reach the maximum value of 45% at 5 ns after breakdown and decrease to less than 20% within 20 ns. The high attenuation characteristics of the shock wave after the optical breakdown are predicted by the numerical method. The quick time and space evolution of the shock wave are carefully analyzed. The normalized shock wave width is found to be independent of the laser energy and duration, and the energy partition ratio is around 2.0 using the nanosecond pulsed laser.
Effects of Lean Mode of Blade Trailing Edge on Pressure Fluctuation Characteristics of a Vertical Centrifugal Pump With Vaned Diffuser
Authors: Zeng Yongshun , Yao Zhifeng , Tao Ran , Liu Weichao , Xiao Ruofu 
Published: June 2021

Abstract
A vertical centrifugal pump with a vaned diffuser is very attractive in the field of long-distance water supply. Excessive pressure fluctuations in the vaneless region due to rotor–stator interaction (RSI) need careful evaluation. In the present investigation, the hydraulic performance and pressure fluctuation characteristics of a vertical centrifugal pump with three different lean modes of the blade trailing edge were quantitatively analyzed by comparison experiments, using the same test rig. Results showed that the pressure fluctuation level was the highest in the vaneless region, closest to the volute tongue, and increased as the flow rate deviated from the design flow rate. The lean mode of the blade trailing edge was found to have a slight influence on hydraulic performance, and the relative deviation of experimental specific speeds with three different lean modes was within 6%. The influence of the lean mode of the blade trailing edge on the pressure fluctuation level was experimentally verified for the first time. In particular, the flow rate-averaged peak-to-peak value of pressure fluctuation with the positive lean mode (PLM) was 62% of the corresponding value with the zero lean mode (ZLM), while no significant improvement was observed for the negative lean mode (NLM). The flow mechanism behind this may be explained as a weakening of the jet-wake flow pattern with PLM.
Fabrication of In Situ TiN Ceramic Particle Reinforced High Entropy Alloy Composite Coatings by Laser Cladding Processing
Authors: Wang X. H. , Liu S. S. , Zhao G. L. , Zhang M. 
Published: June 2021

Abstract
In situ TiN ceramic particle reinforced FeCoNiCrMnTi high entropy alloy coating was fabricated by laser cladding processing at high purity nitrogen gas atmosphere on the AISI 304 stainless steel substrate. The effect of Ti addition on the microstructure, phase structure, and wear properties of the coatings was investigated. The results showed that the phase structure of the coatings was mainly face-centered cubic (FCC)-type γ phase. A few of cubic or flower-like TiN ceramic were formed after adding titanium into the FeCoNiCrMn powder. When atomic ratio of Ti exceeds 0.5, Laves phases appeared in the coatings. With increasing of Ti, the micro-hardness and wear resistance of the coatings increased, but friction coefficient and crack resistance of the coatings reduced. Suitable Ti content in the FeCoNiCrMnTix, laser composite coating, had higher resistance to adhesive wear, oxidation wear, and cracking resistance.
Mechanical, Tribological, and Corrosion Properties of Composite NiP-Al2O3 With Different Amount of Particles
Authors: Pessoa Renato B. , Laurindo Carlos A. H. , Meruvia Michelle S. , Torres Ricardo D. , Mikowski Alexandre , Soares Marcos E. , Soares Paulo 
Published: June 2021

Abstract
In this study, the influence of Al2O3 particle amounts on the mechanical, tribological, and corrosion properties of the composite NiP-Al2O3 coating was evaluated. AISI 4140 steel was coated with NiP through an autocatalytic bath with the addition of Al2O3 particles maintained in suspension by mechanical stirring. Following, the coated samples were annealed at 600 °C to increase the hardness and to create an interdiffusion layer, which improves coating adhesion and corrosion resistance. The coating surface was characterized by scanning electron microscope (SEM)/energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), microhardness, wear resistance, and corrosion tests. The results showed that the coating particles’ amount depends on the bath agitation speed, the sample orientation during the deposition, and the volume of Al2O3 particles in the bath composition. Also, the number of particles in the coating affects the deposition kinetics and the thickness of the interdiffusion layer, which affects the wear and corrosion resistance.
Experimental Investigations on the Effect of Mixing Procedures on the Rheological Properties of Oilwell Cement Slurries
Authors: Saleh Fatemeh K. , Teodoriu Catalin 
Published: June 2021

Abstract
Well cementing is an essential operation in the oil and gas industry, and it is a key material to ensure wellbore integrity through the life of the well. Improper cement design can trigger well construction risks such as de-bonding and leakage pathways near-wellbore and through the annulus. Mixing non-Newtonian fluids is one of the most challenging tasks, especially for pseudoplastic fluids exhibiting yield stress, such as wellbore cement slurry. Mixing conditions for cement slurries and their effect on rheological properties and thickening time have been debated through the literature. In this study, based on laboratory-scale experiments, we provide testing results for rheological properties and thickening time by changing mixing conditions. Our results show that slurries mixed under similar mixing energy do not necessarily result in similar rheological properties. Comparing rheological measurements from lower mixing energy to higher mixing energy, plastic viscosity decreases; however, yield point increases. This implies the dual opposite effect of mixing time on rheological properties. This may have severe implications for field operations where mixing must be improved to enable successful cement operation.
Joint effect of changes in physical activity and weight on incident non-alcoholic fatty liver disease
Authors: Tsai Yi-Lin , Chen Sean Chun-Chang 
Published: June 2021

Background
Increases in physical activity (PA) and weight have opposite effects on the risk of non-alcoholic fatty liver disease (NAFLD), but their joint effect remains unknown. We examined the dose-effect of PA increase for NAFLD prevention and the amount of PA increase required to offset the deleterious effect of weight gain.

Methods
We analysed 47 058 participants who were extracted from the Taiwan MJ cohort, aged 20–50 years, without NAFLD at baseline, and followed at 1–5 years between 1997 and 2016. The outcome was incident NAFLD, diagnosed by ultrasonography. PA was measured by metabolic equivalents (METs) and duration (hour/week). We used flexible parametric survival models to estimate the HRs of annual change in PA and body mass index (BMI), controlling for their interaction and baseline covariates.

Results

During 138 646 person-years of follow-up, 12 836 participants (40.6% men and 20.1% women) developed incident NAFLD. The HR (95% CI) of annual PA increase of 1 MET-hour/week was 0.88 (0.85–0.92) after controlling for weight change. Moreover, 28 min/week of moderate-intensity PA could neutralise NAFLD risk elevated by annual BMI increase of 0.1 kg/m
2
at the end of year 3. We also observed an extra 35% risk reduction when PA increase (1 MET-hour/week) and weight loss (0.1 kg/m
2
) occurred simultaneously.

Conclusions
Annual PA increase of 1 MET-hour/week was associated with a 12% lower NAFLD risk. PA increase can counteract the harmful effect of weight gain and there is a synergistic effect from PA increase and weight loss.
Epidemiology of herpes simplex virus type 2 in Latin America and the Caribbean: systematic review, meta-analyses and metaregressions
Authors: Harfouche Manale , Maalmi Haifa , Abu-Raddad Laith J 
Published: June 2021

ObjectiveTo characterise epidemiology of herpes simplex virus type 2 (HSV-2) in Latin America and the Caribbean.MethodsHSV-2 reports were systematically reviewed and synthesised, and findings were reported following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Meta-analyses and metaregressions were conducted.Finding102 relevant reports were identified including 13 overall incidence measures, 163 overall (and 402 stratified) seroprevalence measures, and 7 and 10 proportions of virus detection in genital ulcer disease and in genital herpes, respectively. Pooled mean seroprevalence was 20.6% (95% CI 18.7% to 22.5%) in general populations, 33.3% (95% CI 26.0% to 41.0%) in intermediate-risk populations, 74.8% (95% CI 70.6% to 78.8%) in female sex workers, and 54.6% (95% CI 47.4% to 61.7%) in male sex workers, men who have sex with men and transgender people. In general populations, seroprevalence increased from 9.6% (95% CI 7.1% to 12.4%) in those aged <20 years to 17.9% (95% CI 13.6% to 22.5%) in those aged 20–30, 27.6% (95% CI 21.4% to 34.2%) in those aged 30–40 and 38.4% (95% CI 32.8% to 44.2%) in those aged >40. Compared with women, men had lower seroprevalence with an adjusted risk ratio (ARR) of 0.68 (95% CI 0.60 to 0.76). Seroprevalence declined by 2% per year over the last three decades (ARR of 0.98, 95% CI 0.97 to 0.99). Pooled mean proportions of HSV-2 detection in GUD and genital herpes were 41.4% (95% CI 18.9% to 67.0%) and 91.1% (95% CI 82.7% to 97.2%), respectively.ConclusionsOne in five adults is HSV-2 infected, a higher level than other world regions, but seroprevalence is declining. Despite this decline, HSV-2 persists as the aetiological cause of nearly half of GUD cases and almost all of genital herpes cases.
Where did my 256 GB go? A Measurement Analysis of Storage Consumption on Smart Mobile Devices
Authors: Bijlani Ashish , Ramachandran Umakishore , Campbell Roy 
Published: June 2021

This work presents the first-ever detailed and large-scale measurement analysis of storage consumption behavior of applications (apps) on smart mobile devices. We start by carrying out a five-year longitudinal static analysis of millions of Android apps to study the increase in their sizes over time and identify various sources of app storage consumption. Our study reveals that mobile apps have evolved as large monolithic packages that are packed with features to monetize/engage users and optimized for performance at the cost of redundant storage consumption.
We also carry out a mobile storage usage study with 140 Android participants. We built and deployed a lightweight context-aware storage tracing tool, called cosmos, on each participant's device. Leveraging the traces from our user study, we show that only a small fraction of apps/features are actively used and usage is correlated to user context. Our findings suggest a high degree of app feature bloat and unused functionality, which leads to inefficient use of storage. Furthermore, we found that apps are not constrained by storage quota limits, and developers freely abuse persistent storage by frequently caching data, creating debug logs, user analytics, and downloading advertisements as needed.
Finally, drawing upon our findings, we discuss the need for efficient mobile storage management, and propose an elastic storage design to reclaim storage space when unused. We further identify research challenges and quantify expected storage savings from such a design. We believe our findings will be valuable to the storage research community as well as mobile app developers.