bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence Coefficients for Edge-Loaded Short, Thin, Conical Frustums
Authors: Baltrukonis J. H. 
Published: June 2021

Abstract
An exact solution is obtained in terms of Kelvin functions for axisymmetrically edge-loaded, short, thin, conical frustums. Expressions for the edge-deflectional and rotational influence coefficients are presented in matrix form. Approximate expressions for the influence coefficients are evolved by using one-term asymptotic expansions for the Kelvin functions. It is shown that the range of validity is somewhat larger for this approximate solution than for the solution by Horvay, Linkous, and Born.
Analysis of a Compression Test of a Model of a Granular Medium
Authors: Thurston C. W. , Deresiewicz H. 
Published: June 2021

Abstract
A granular medium is idealized here by a model composed of contiguous like spheres arranged in a face-centered cubic lattice. Total stress-strain relations for this model are derived by integrating incremental relations, given previously by Duffy and Mindlin, for a loading program which consists of a uniaxial compression applied concurrently with a related isotropic pressure. Further, the failure stress in uniaxial compression is determined as a function of initial pressure. Results of experimental work are reported which agree with predictions of the theory.
Creep of Thick-Walled Tubes Under Internal Pressure Considering Large Strains
Authors: Rimrott F. P. J. 
Published: June 2021

Abstract
Using the generally accepted assumptions of constant density, zero axial strain, and the distortion-energy law, equations are derived for the creep rates, strains, and stresses of a thick-walled, closed-end, circular, hollow cylinder under internal pressure and made of an isotropic and homogeneous material. The strains are considered large, requiring the use of the finite-strain theory. A known creep rate versus stress relation is then used to solve a specific problem.
Vibration of Beam-Mass Systems With Time-Dependent Boundary Conditions
Authors: Yen T. C. , Kao S. 
Published: June 2021

Abstract
Vibration problems of beams with time-dependent boundary conditions are solved by the method of Laplace transforms. The problems treated include the simply supported, cantilevered, and fixed beams carrying a single arbitrarily placed mass; two equal masses symmetrically placed on a simply supported or fixed-end beam and a beam carrying a mass at the center and two equal masses at tips, striking a spring.
On the Instability and Folding Deformation of a Layered Viscoelastic Medium in Compression
Authors: Biot M. A. 
Published: June 2021

Abstract
When a layer of material embedded in an infinite medium is subject to a compression parallel with the layer an instability tends to develop which manifests itself in the folding of the layer. This phenomenon is examined here for the general case where the layer and the surrounding medium are both viscoelastic. This problem which was examined in preliminary form in an earlier publication [6] is treated here with particular attention to the effect of interfacial adherence of the layer and the medium, and to an evaluation of the amplitude of the folding. In general there is a lower and upper-critical value of the compressive load between which folding occurs with a finite rate of deformation. There appears also a dominant wave length, for which the rate of folding is maximum under a given load. The dominant wave length may or may not depend on the load. The effect of interfacial adherence while not negligible is not generally significant. The rate of folding increases very rapidly beyond a certain value of the viscosity ratio of the two media. A brief discussion is also included of the thermodynamic implications of incremental stress-strain relations in prestressed media.
The Stress Distribution in a Semi-Infinite Strip Subjected to a Concentrated Load
Authors: Theocaris P. S. 
Published: June 2021

Abstract
A solution is presented for the stress distribution in a semi-infinite strip subjected to an axial concentrated compressive load. The problem is solved by using the function z = f(w) defining the Schwarz-Christoffel transformation. All the boundary conditions are satisfied except along the two longitudinal edges of the strip. Normal stresses along these boundaries are present which are eliminated by applying the minimum-strain-energy principle at a part of the strip. The stress components are calculated along all the boundaries and the axis of symmetry, as well as along three transverse sections in the neighborhood of the applied load. The theoretical results are compared with experimental results obtained by using photoelasticity and the electrical analogy method for the tracing of isostatics.
Postbuckling Behavior of Rectangular Plates With Small Initial Curvature Loaded in Edge Compression
Authors: Yamaki Noboru 
Published: June 2021

Abstract
The solution of Marguerre’s fundamental equations for large deflections of thin plates with slight initial curvature is presented for the case of a rectangular plate subjected to edge compression. The problem is solved under eight different boundary conditions, combining two kinds of loading conditions and four kinds of supporting conditions. Numerical solutions are obtained for square plates with and without initial deflection, and the connections of deflection, edge shortening, and effective width of the plate with applied loads are clarified. The solutions here obtained include as special cases those investigated by Levy and Coan.
The Determination of Safe Loads of Beams Subjected to Combined Twisting and Biaxial Bending Moments
Authors: Hodge P. G. , Sankaranarayanan R. 
Published: June 2021

Abstract
Using the lower-bound theorem of limit analysis, a yield criterion is obtained in terms of the stress resultants for a beam, subjected to combined twisting and biaxial bending moments. Based on a piecewise linear approximate yield condition, the “collapse load” is determined for a right-angle bent, subjected to a load in an arbitrary direction applied to the mid-point of one leg. Such a collapse load, which is a “safe load” for the beam, is plotted as a function of a suitable parameter.
Slow Rotatory Motion of a Circular Disk About One of Its Diameters in a Viscous Fluid
Authors: Kanwal R. P. 
Published: June 2021

Abstract
An analytic solution is presented for the case when a rigid circular plate is made to rotate about a diameter in its plane, in an infinite mass of viscous fluid. Formulas are derived for the velocity components, pressure, and the couple experienced by the disk.
On Inertia Effects in a Transient Thermoelastic Problem
Authors: Sternberg Eli , Chakravorty J. G. 
Published: June 2021

Abstract
This paper is concerned with the dynamic treatment of a transient thermoelastic problem for a semi-infinite medium which is constrained against transverse displacements and is exposed to a uniform time-dependent heating (or cooling) of its entire plane boundary. The stress distribution appropriate to this problem, in the event that the surface temperature is a step-function of time, was previously established by Danilovskaya [1] and by Mura [2]. In the present investigation the accompanying displacements are determined in closed form. In addition, an exact closed solution, in terms of error functions, is obtained for the case in which the time-dependence of the given surface temperature is of the ramp-type. The ensuing field of thermal stress is compared with the corresponding quasi-static stress distribution, with a view toward a quantitative assessment of the accompanying inertia effects as influenced by the rate at which the temperature of the boundary is altered. The results indicate that the conclusions reached in [1] and [2] are in need of essential modification once the assumption of an instantaneous change of the surface temperature is abandoned.
Production of Rotation in a Confined Liquid Through Translational Motion of the Boundaries
Authors: Berlot R. R. 
Published: June 2021

Abstract
The motion of a fluid contained in a cylindrical tank driven laterally to its axis is analyzed in terms of a combination of surface waves and a two-dimensional combined vortex. Nonlinearities are introduced by analogy with the motions of a set of spherical pendulums. The results of theory and experiment agree within the limits of experimental error and the approximations of the theory.
Nonlinear Creep Deformations of Columns of Rectangular Cross Section
Authors: Bleich H. H. , Dillon O. W. 
Published: June 2021

Abstract
Creep deformations of columns of rectangular cross section are studied for the case of materials following the nonlinear law ϵ̇ = (1/E) σ̇ + λσk. The essential point of the paper is the following: The time rate of the curvature κ̇ of an element of a bar loaded by a constant force P and an increasing bending moment M(t) has bounds, which depend on P and on the instantaneous values of M and Ṁ, but not on the history of M. In combination with the collocation method, this permits the formulation of ordinary differential equations for upper and lower bounds on the deformations. Closed solutions for the critical time are obtained for one bound, while the other requires numerical integration. The bounds which are a function of the initial eccentricity are reasonably close and are presented in tables and graphs. By qualitative reasoning it is further shown that the location of the actual critical time with respect to the two bounds is governed by the ratio of the column load P and the nominal Euler buckling load PE of the column if it were elastic.
Viscous Flow Through Tubes of Multiply Connected Cross Sections
Authors: Gaydon F. A. , Nuttall H. 
Published: June 2021

Abstract
A new method is proposed for estimating the volume flow of a viscous incompressible fluid through a cylindrical tube of multiply connected cross section. The method brackets the magnitude of the volume flow between upper and lower bounds. The essential feature of the method is that the calculation of both upper and lower bounds is based upon the same approximating function for the velocity distribution, thus avoiding the usual approach to a lower bound via the Rayleigh-Ritz method. For multiply connected cross sections of the form discussed, a Rayleigh-Ritz solution of sufficient accuracy becomes extremely laborious. Efforts to solve the problem by relaxation methods are also rendered difficult by the presence of high-velocity gradients in the vicinity of an internal boundary, particularly when this is a small circle. In contrast to these methods the one presented achieves the result with considerably less labor; moreover, the method is directly applicable to simply connected cross sections with many-sided boundaries.
Developments in the Application of the Grid Method to Dynamic Problems
Authors: Durelli A. J. , Dally J. W. , Riley W. F. 
Published: June 2021

Abstract
The objective of the research reported in this paper was to develop the grid method further for use in dynamic-stress studies. A rubber-thread grid network in a low-modulus model material (a urethane rubber known as Hysol 8705) was used in conjunction with a microflash light source to record grid distortions and photoelastic fringe patterns in a model subjected to dynamic-loading conditions. By considering a strut subjected to axial impact it was possible to establish that the static and dynamic values of Poisson’s ratio were identical, and the strain-fringe value of the material varied with strain rate. In addition, stresses in the axial and transverse directions were determined along the center line of the strut. Finally, the methods established were applied to the problem of a circular disk subjected to diametrical impact and both principal stresses were determined along a vertical diameter at one instant during impact.
Transient Analysis of Stress-Wave Penetration in Plates
Authors: Davids Norman 
Published: June 2021

Abstract
This paper carries out an analysis of the propagation of a transient stress pulse concentrated at a point on the boundary of a plate whose thickness is of the order of a wave length. It is based on an expansion method used by Caignard in geophysical-layer problems which obviates the contour-integration difficulties and whose terms represent successively reflected waves of increasing time delay. From the general formulas obtained in this paper for an arbitrary forcing function, the stress versus time distribution along the axis of a 1-in-thick aluminum plate is obtained for a 5-microsec exponentially decaying pressure pulse. Inside the plate it is found there is a compressed zone which is relieved by a negative front traveling with the distortional wave velocity. When this interferes with a certain reflected negative front, the stress reverses in sign. A comparison of the location of this reversal is made with those based on plane-wave assumptions. Limiting cases are discussed.
Transverse Flexure of a Semi-Infinite Thin Plate Containing an Infinite Row of Circular Holes
Authors: Tamate O. 
Published: June 2021

Abstract
The problem of finding stress resultants in a semi-infinite plate under plain bending and containing an infinite row of equal and equally spaced circular holes is discussed on the basis of the Poisson-Kirchhoff theory of thin plates. A method of perturbation is adopted for the determination of parametric coefficients included in the solution. The maximum bending moments occurring on the rim of the hole across the minimum section are calculated for several cases and shown in graphs, from which the mutual interference of adjacent boundaries will be informed.
Large-Eddy Simulation Investigation of Modified Rib Shapes on Heat Transfer in a Ribbed Duct
Authors: Sreekesh K. , Tafti D. K. , Vengadesan S. 
Published: June 2021

Abstract
Internal cooling of the gas turbine blade is critical for the durability of the blade material. One of the ways to accomplish this is by passing coolant through serpentine passages roughened with surface elements to enhance the heat transfer. In the present study, the traditional square rib (SQ-rib) placed normal to the flow direction is modified to a backward-facing step rib (BS-rib) and a forward-facing step rib (FS-rib). Large-eddy simulation (LES) is carried out for a square duct at Reb = 20000. Results show that the modified rib shapes result in substantial increase in heat transfer over the square rib with only a marginal increase in flow losses. The BS-rib shape produces the highest heat transfer augmentation followed by the FS-rib. The overall heat transfer augmentation for the BS-rib and FS-rib is 18% and 10% larger than the SQ-rib, respectively. Thermal-hydraulic performance is enhanced by 15%.
Assessment of Spray and Pool Scrubbing Efficiencies for Means of Mitigation Against Aerosol Dispersion in the Context of Fuel Debris Retrieval at Fukushima Daiichi: Part II
Authors: Porcheron Emmanuel , Leblois Yohan , Gelain Thomas , Chagnot Christophe , Journeau Christophe , Roulet Damien 
Published: June 2021

Abstract
The general context of this paper is an evaluation of strategies that can be used to mitigate aerosol dispersion during fuel debris or corium retrieval in damaged Fukushima Daiichi reactors. Knowledge of the aerosol source terms released during fuel debris retrieval operations is one of the key factors for assessing aerosol dispersion leading to the potential dissemination of radionuclides into the environment. Our approach is to couple experimental results from integral tests obtained during laser cutting experiments, well-controlled analytical tests with separated effects performed in a dedicated facility to reproduce two-phase flow such as flows representative of pool scrubbing and spray scrubbing conditions, and numerical simulations. Integral tests provide relevant information on the airborne particle release fraction during laser cutting for underwater conditions at different water depths, such as the particle concentration and particle size distribution. However, the detailed characterization of two-phase flows, such as the size and velocity of gas bubble and water droplets generated by spray systems, is not possible during laser cutting integral tests. Therefore, a more analytical approach is necessary to obtain detailed information on two-phase flow, composed of bubbles in water, inducing pool scrubbing phenomenon, and droplets in gas generated by spray scrubbing systems used for mitigating dust dispersion, which are essential to the physical mechanisms of both processes and enable their respective efficiencies to be evaluated. The main objectives of this work were to develop models and ensure their validation based on experimental approach for predicting the pool scrubbing and spray scrubbing efficiencies in the context of fuel debris removal at Fukushima Daiichi.
Non-Dimensional Parameters for Comparing Conventional and Counter-Rotating Turbomachines
Authors: Waldren J. J. , Clark C. J. , Grimshaw S. D. , Pullan G. 
Published: June 2021

Abstract
Counter-rotating turbomachines have the potential to be high efficiency, high power density devices. Comparisons between conventional and counter-rotating turbomachines in the literature make multiple and often contradicting conclusions about their relative performance. By adopting appropriate non-dimensional parameters, based on relative blade speed, the design space of conventional machines can be extended to include those with counter-rotation. This allows engineers familiar with conventional turbomachinery to transfer their experience to counter-rotating machines. By matching appropriate non-dimensional parameters, the loss mechanisms directly affected by counter-rotation can be determined. A series of computational studies are performed to investigate the relative performance of conventional and counter-rotating turbines (CRTs) with the same non-dimensional design parameters. Each study targets a specific loss source, highlighting which phenomena are directly due to counter-rotation and which are solely due to blade design. The studies range from two-dimensional blade sections to three-dimensional finite radius stages. It is shown that, at hub-to-tip ratios (HTRs) approaching unity, with matched non-dimensional design parameters, the stage efficiency and work output are identical for both types of machines. However, a CRT in the study is shown to have an efficiency advantage over a conventional machine of up to 0.35 percentage points for a HTR of 0.65. This is due to differences in absolute velocity producing different spanwise blade designs.
Chemical Condensation Wave Initiating Oxygen-Free Combustion and Detonation
Authors: Emelianov A. V. , Eremin A. V. , Fortov V. E. 
Published: June 2021

Abstract
It is well known that the propagation of traditional combustion and detonation waves was determined by the branched chain reactions discovered by Academician N.N. Semenov. This article discusses a new type of detonation waves initiated by chemical condensation processes. Chemical condensation waves arise as a result of the heat released during the explosive condensation of a highly supersaturated carbon vapor formed as a result of the dissociation of the initial carbon-containing molecules behind the front of the initiating shock wave. Unlike traditional combustion and detonation waves, the mechanism of chemical condensation does not include branched chain reactions; nevertheless, the laws of propagation of detonation waves of condensation are clearly described by the Zel’dovich–Neumann–Döring theory.
Development of Photoactive Supramolecular Devices and Machines
Authors: Gromov S. P. , Chibisov A. K. , Alfimov M. V. 
Published: June 2021

Abstract
Among the various directions of the science of photoactive organic compounds, the design, creation, and study of photoactive supramolecular devices and machines are attracting special attention, since in this way it is possible to discover new approaches to construct complex hierarchical “smart” materials.
Safety and efficacy of inpatient pulmonary rehabilitation for patients hospitalised with an acute exacerbation of chronic obstructive pulmonary disease: a systematic review protocol
Authors: Zhu Kai , Gill Jagdeep , Kirkham Ashley , Chen Joel , Ellis Amy , Crosbie Stephanie , Denson-Camp Holly , Peters Hannah , Camp Pat 
Published: June 2021

IntroductionPulmonary rehabilitation (PR) following an acute exacerbation of chronic obstructive pulmonary disease (AECOPD) reduces the risk of hospital admissions, and improves physical function and health-related quality of life. However, the safety and efficacy of in-hospital PR during the most acute phase of an AECOPD is not well established. This paper describes the protocol for a systematic review with meta-analysis to determine the safety and efficacy of inpatient acute care PR during the hospitalisation phase.Methods and analysisMedical literature databases and registries MEDLINE, EMBASE, Physiotherapy Evidence Database, Cumulative Index to Nursing and Allied Health Literature, Canadian Agency for Drugs and Technologies in Health, CENTRAL, Allied and Complementary Medicine Database, WHO trials portal and ClinicalTrials.gov will be searched for articles from inception to June 2021 using a prespecified search strategy. We will identify randomised controlled trials that have a comparison of in-hospital PR with usual care. PR programmes had to commence during the hospitalisation and include a minimum of two sessions. Title and abstract followed by full-text screening will be conducted independently by two reviewers. A meta-analysis will be performed if there is sufficient homogeneity across selected studies or groups of studies. The Population, Intervention, Comparator, Outcomes and Study characteristics framework will be used to standardise the data collection process. The quality of the cumulative evidence will be assessed using the Grading of Recommendations, Assessment, Development and Evaluations framework.Ethics and disseminationAECOPD results in physical limitations which are amenable to PR. This review will assess the safety and efficacy of in-hospital PR for AECOPD. The results will be presented in a peer-reviewed publication and at research conferences. Ethical review is not required for this study.PROSPERO registration numberCRD42021198877.