bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surgical treatment of canine and feline descemetoceles, deep and perforated corneal ulcers with autologous buccal mucous membrane grafts
Authors: Mezzadri Valentina , Crotti Alberto , Nardi Samanta , Barsotti Giovanni 
Published: June 2021

AbstractObjectivesTo report the surgical technique and postoperative outcome of corneal repair with autologous buccal mucous membrane grafts in dogs and cats with descemetoceles, deep corneal ulcers, and perforated corneal ulcers with or without iris prolapse.Animal studiedTwelve cats (13 eyes) and fourteen dogs (14 eyes) were treated.ProceduresGrafts were harvested from the unpigmented superior labial mucosa using a biopsy punch. The corneal lesion was carefully debrided and cleaned. The graft was secured to the healthy cornea with a combination of simple interrupted and continuous 9–0 polyglycolic acid sutures. In 25/27 treated eyes, an overlying pedicle conjunctival graft was also performed. A temporary nictitating membrane flap was used in all cases. The pedicle conjunctival graft was trimmed about 10–20 days postoperatively. The median follow‐up period was 549.2 days (range 14–2691 days).ResultsNo surgical intra‐operative complications were observed. The ulcers healed and the integrity of the globe was restored in 24/27 treated eyes. Different grades of corneal fibrosis and/or vascularization and/or pigmentation were observed in all cases at the long‐term follow‐up. In two cases, enucleation was performed due to postoperative complications and one animal developed phthisis bulbi. A total of 22/27 treated eyes appeared to have regained effective visual function at the last clinical evaluation.ConclusionsAutologous buccal mucous membrane grafts appear to successfully manage severe corneal ulcers in dogs and cats, providing a useful and economical alternative to other corneal grafts.
Stability of Thin Elastic Plates Covering an Arbitrary Simply Connected Region and Subject to any Admissible Boundary Conditions
Authors: Zizicas G. A. 
Published: June 2021

Abstract
The Bergman method of solving boundary-value problems by means of particular solutions of the differential equation, which are constructed without reference to the boundary conditions, is applied to the problem of stability of thin elastic plates of an arbitrary simply connected shape and subject to any admissible boundary conditions. A direct method is presented for the construction of particular solutions that is applicable to both anisotropic and isotropic plates. Previous results of M. Z. Krzywoblocki for isotropic plates are obtained in a simple manner.
Numerical Analysis of Forced Vibrations of Beams
Authors: Myklestad N. O. 
Published: June 2021

Abstract
In this paper a simple tabular method is developed by which the vibration amplitudes, bending moments, and shear forces of a beam of variable but symmetrical cross section, carrying any number of concentrated masses and acted on by any number of harmonically varying forces, can be found. The driving forces must all have the same frequency but the phase angles may be different. The method is an extension of the one employed by the author to find natural modes of vibration of beams, but in the case of forced vibration only one application of the tabular calculations is necessary, making it essentially a far simpler problem than that of finding the natural modes. Internal damping of the beam material is easily considered and should always be taken into account if there is any danger that the forced frequency is near any one of the natural frequencies.
The Necking and the Rupture of Rods Subjected to Constant Tensile Loads
Authors: Hoff N. J. 
Published: June 2021

Abstract
A one-dimensional theory of the behavior of a nonlinear viscoelastic bar subjected to a constant tensile load is developed with the aid of a creep law considering secondary creep alone. The theoretical value of the time at which the bar ruptures and the shape calculated for the necked portion of the bar are in satisfactory agreement with the results of experiments.
On the Plastic Strains in Slabs With Cutouts
Authors: Hodge P. G. 
Published: June 2021

Abstract
The complete elastic-plastic problem is set up for a circular slab with a central circular cutout, subjected to uniform external tension. The analysis is carried out under the assumption of generalized plane stress but with possibly finite deformations. The material is assumed to be isotropic, homogeneous, and incompressible, to yield according to the Tresca yield condition, and to satisfy Hooke’s law in the elastic domain and the plastic potential law in the plastic domain. The equations are solved by a perturbation method based on the ratio of the maximum shear stress to the shear modulus, in which each of the significant quantities, stress, displacement, and slab thickness, is expanded in a power series in this ratio. A similar technique is employed to solve the fully plastic flow problem. It is shown that for cutout radii greater than 1 per cent of the radius of the slab, the “first approximations” obtained by neglecting all but the leading term in each series are satisfactory, up to loads at which the slab becomes wholly plastic. The ratio of the maximum strain in the just fully plastic slab to that in the completely elastic slab is computed. It is found that this ratio is less than about 6 if the cutout radius is at least 1 per cent of the radius of the slab. Some observations are advanced on the case where the cutout is very small compared to the slab.
Transient Thermal Stresses in Slabs and Circular Pressure Vessels
Authors: Heisler M. P. 
Published: June 2021

Abstract
This paper presents the results of computations for determining transient thermal stresses in slabs and circular pressure vessels. The process of solution adopted is to substitute transient-temperature formulas into the already available stress expressions. The expressions for thermal shock are transformed by means of a simple integral theorem into a form appropriate for analyzing the thermal processes commonly used to relieve thermal shock. A new dimensionless stress parameter is defined and applied to the determination of optimum heating or cooling times of massive pressure vessels.
Constant-Strain Waves in Strings
Authors: Cole J. D. , Dougherty C. B. , Huth J. H. 
Published: June 2021

Abstract
A nonlinear theory is developed for constant-strain waves in elastic strings. The speed of longitudinal and transverse waves is related to the strain and tension. The results can be used to calculate tension resulting from impact and thus breaking loads. Some generalizations are suggested.
On Reinforced Circular Cutouts
Authors: Levin E. 
Published: June 2021

Abstract
A slab with a circular cutout is subjected to stresses in the plane of the slab. The cutout has removed material which would have participated in carrying the load; hence the slab with cutout will fail under the application of stresses which the complete slab could have supported. In order to eliminate at least part of this weakening, the slab with cutout may be reinforced by the addition of material about the cutout. Such a reinforcement may be designed in any shape. The paper is concerned with extending the results of Weiss, Prager, and Hodge (1) for a cylindrical reinforcement to a reinforcement of arbitrary shape. In particular, a method will be described for the determination of a lower bound on the collapse load for a slab with circular cutout and a general reinforcement.
The Wave Method for Solving Flexural Vibration Problems
Authors: Jones R. P. N. 
Published: June 2021

Abstract
In this paper the use of normal mode and wave methods in problems of dynamic loading on beams is discussed, and the methods are applied to simple problems of uniform beams under a suddenly applied load. For these problems, mathematically exact results have been obtained, enabling a comparison to be made between the two types of solution. Experimental results for these problems also have been obtained, using an apparatus which releases the beam from a deflected position, and displays a record of the resultant response on an oscillograph screen, using a time base synchronized with the release of the beam. Good agreement is obtained between the experimental and theoretical results, and it is shown that the wave solution is useful for determining the initial response of the beam, while the subsequent response can be better obtained from the normal-mode solution.
Stress Concentrations Around a Small Spherical or Spheroidal Inclusion on the Axis of a Circular Cylinder in Torsion
Authors: Das Sisir Chandra 
Published: June 2021

Abstract
Stresses are calculated for the case of a small elastic inclusion bonded (i.e., continuous displacements and tractions across the surface of the inclusion) to a large circular cylindrical shaft. The inclusions considered are of spherical and spheroidal shapes. The results are discussed for several particular cases.
Plastic Flow in a Rectangularly Notched Bar Subjected to Tension
Authors: Lee E. H. 
Published: June 2021

Abstract
A two-dimensional notched bar with rectangular root pulled in tension is considered. Large strains are analyzed so that plastic-rigid theory can be used. The initial motion based on the undeformed boundaries is considered, and also the subsequent flow including the deformation of the notch boundaries. In the absence of fracture, the solution can be continued until only line contact occurs at the notch root. The solution satisfies stress and velocity conditions for a St. Venant-Mises material in plastic flow at each stage of the deformation. The unsteady, large strain, motion can be analyzed, including the determination of the unknown free surface and the plastic-rigid boundary, due to a special property of the velocity solution and to the statical determinacy of the stress field in terms of the free-surface geometry.
Transmission of Tension From a Bar to a Plate
Authors: Goodier J. N. , Hsu C. S. 
Published: June 2021

Abstract
When a bar or strip is lap-jointed to a plate, and transmits tension to it, the transmission is not effected only by a smooth distribution of force along the lap joint; there is also a highly concentrated force, a considerable fraction of the total tension, where the bar meets the plate, and a second force at the end of the bar. These forces are investigated by strain-gage measurements for various lengths of lap, and by a plane-stress calculation, with fair agreement. The results suggest that the fatigue strength of such joints will depend on the detailed local character of the joint where the bar meets the plate, rather than on the length of the joint.
On the Equations of Motion of Cylindrical Shells
Authors: Naghdi P. M. , Berry J. G. 
Published: June 2021

Abstract
From the basic equations of thin cylindrical shells consistent with Love’s first approximation, three uncoupled displacement equations of motion are deduced, the effect of rotary inertia being neglected. Comparison is made with the works of other authors who have used a variety of approximations in arriving at the equations of motion of cylindrical shells. Thus, in a qualitative manner, further insight is gained as to the effectiveness and practicality of these approximations in the solutions of problems of cylindrical shells.
On the Thickness of Normal Shock Waves in a Perfect Gas
Authors: Shapiro A. H. , Kline S. J. 
Published: June 2021

Abstract
An approximate method for calculating the thickness of shocks in perfect gases, similar to the integral methods of ordinary boundary-layer theory, is formulated and leads to an explicit formula relating a shock-thickness Reynolds number to the Prandtl number, ratio of specific heats, and Mach number entering the shock. The method takes account of the variation of viscosity with temperature. The results of the approximate theory are in exact accord with the known exact solutions for (a) the case where the Prandtl number is 3/4 and the viscosity and heat conductivity are constant, (b) the case where the shock is very weak, and (c) the case where the gas has finite viscosity but zero conductivity. In addition, the approximate theory is in good agreement with results obtained on a differential analyzer showing the effects of Prandtl number and variation of viscosity with temperature. The results also are expressed in terms of the ratio of shock thickness to mean free molecular path in the inlet gas. This ratio is given in terms of the Prandtl number, ratio of specific heats, and shock strength. In the absence of relaxation effects, the numerical magnitudes suggest that the continuum theory is accurate for inlet Mach numbers below about 1.5, whereas for higher Mach numbers the continuum theory is indicative of general orders of magnitude.
A Critical Examination of Procedures Used in Britain and the United States to Determine Creep Stresses for the Design of Power Plant for Long Life at High Temperatures
Authors: Bailey R. W. 
Published: June 2021

Abstract
The operating life of land power plant being far longer than allowable testing times for the constructional metals, the selection of a material, or the determination of its appropriate working stress, is dependent in an important degree upon the procedure followed in utilizing the creep-test results obtained. Different procedures practiced both in Britain and in the United States can result in different views regarding the potentialities of a material, and also about the working stress allowable. The paper examines the more commonly used procedures and focuses attention upon the factors present which would operate to introduce uncertainty and error as between the probable behavior in the long time of actual service, and as yielded by a test procedure. The principal disturbing factor in altering the resistance to creep of the material is thermal action. In some procedures, especially where the creep tests are made at working temperatures, the influence of this factor may be small or negligible in the procedure, compared with its magnitude in service. The need is emphasized for thermal action to be taken adequately into account by the test procedure. Next in importance as a possible source of error is the method of extrapolation beyond the test times to the time of the operating life. The factor of thermal action and of its representation in the several procedures examined is considered. The circumstances of extrapolation are similarly investigated, especially in regard to whether the result would overestimate or underestimate the safe working stress. Satisfying comparisons of working stresses using different procedures cannot at present be made. The position is therefore disappointing and one which it is very desirable should be rectified.
Anisotropic Loading Functions for Combined Stresses in the Plastic Range
Authors: Hu L. W. , Marin Joseph 
Published: June 2021

Abstract
A loading function is a relation between combined stresses for which the beginning of plastic flow takes place. The loading function for a given material is different depending upon the initial plastic strains produced. That is, the initial stress or strain history influences the subsequent loading function. This paper gives the results of an experimental investigation to determine the validity of certain loading functions proposed for anisotropic materials. The study reported was conducted for an aluminum alloy 24S-T and the state of stress covered was biaxial tension. These stresses were produced in the usual way by subjecting thin-walled tubular specimens to axial tension and internal pressure. The test results showed that none of the existing loading functions is adequate for interpreting the plastic stress-strain relations obtained. Tests also were made to determine the change in the loading function with increase in plastic flow. It was found that the loading function did not remain symmetrical with respect to the original function, nor was the new loading function the same as the original except for a shift of origin. However, the test results support in a qualitative way the concept of the so-called “yield corner.”
Harmonic Oscillations of Nonlinear Two-Degree-of-Freedom Systems
Authors: Huang T. C. 
Published: June 2021

Abstract
In this paper an investigation is made of equations governing the oscillations of a nonlinear system in two degrees of freedom. Analyses of harmonic oscillations are illustrated for the cases of (1) the forced oscillations with nonlinear restoring force, damping neglected; (2) the free oscillations with nonlinear restoring force, damping neglected; and (3) the forced oscillations with nonlinear restoring force, small viscous damping considered. Amplitudes of oscillations and frequency equations are derived based on the mathematically justified perturbation method. Response curves are then plotted.
The Effect of a Surrounding Fluid on Pressure Waves in a Fluid-Filled Elastic Tube
Authors: Junger M. C. 
Published: June 2021

Abstract
The analysis of the transmission of pressure waves in a fluid-filled elastic tube has been extended to the case where the tube is surrounded by a fluid medium. The sound pressure inside the tube is the resultant of a number of modes, some of which are nonpropagating, while others propagate at their own characteristic phase velocities. Neglecting end effects, and for continuously generated waves, it is found that only the modes whose velocity is larger than the sound velocity of the surrounding medium radiate sound energy radially outward. These modes will be damped out by radiation losses, while modes having a phase velocity smaller than this sound velocity are propagated without attenuation (if viscous and heat-transfer losses are neglected). Consequently, if the fluid is the same in the surrounding medium and in the tube only the lowest mode, which resembles a plane wave, propagates unattenuated. In any case, the mass-loading of the surrounding fluid lowers the phase velocities of the propagating modes, particularly at intermediate frequencies. It is shown that in this application the membrane theory of shells will lead to incorrect results, even in thin-walled tubes. This is illustrated by comparison with experimental data.
Stresses Due to Diametral Forces on a Circular Disk With an Eccentric Hole
Authors: Sen Gupta A. M. 
Published: June 2021

Abstract
In this paper stresses in a circular disk with an eccentric circular hole have been determined when the disk is compressed along the line of centers by two equal and opposite forces acting on its outer edge, the inner edge being unstressed. From the results obtained, the solution of the problem of a semi-infinite plate acted on by a concentrated normal force on its straight boundary and containing an unstressed circular hole has been deduced.
Limits of Economy of Material in Plates
Authors: Hopkins H. G. , Prager W. 
Published: June 2021

Abstract
The paper is concerned with the limits of economy of material in a simply supported circular plate under a uniformly distributed transverse load. The plate material is supposed to be plastic-rigid and to obey Tresca’s yield condition and the associated flow rule. The criterion of failure adopted is that used in limit analysis. It is shown that the plate of uniform thickness has a weight efficiency of about 82 per cent. Stepped plates of segmentwise constant thickness are discussed, and the plate of continuously varying thickness is treated as the limiting case obtained by letting the number of steps go to infinity.
Theory of Plastic Buckling of Plates and Application to Simply Supported Plates Subjected to Bending or Eccentric Compression in Their Plane
Authors: Bijlaard P. P. 
Published: June 2021

Abstract
After some general considerations on the plastic buckling of plates, the plastic buckling stresses are calculated for long plates, subject to longitudinal bending or eccentric compression in their plane, and simply supported at their unloaded edges. The solutions are based on the author’s theory of plastic plate buckling and are obtained by reducing the governing partial differential equation to ordinary finite-difference equations. Second-order finite differences are used, with a spacing equal to one ninth of the plate width. A simple design formula is presented for the plastic reduction factor with which the elastic buckling stress has to be multiplied for obtaining the plastic buckling stress.
On Axially Symmetric Bending of Nearly Cylindrical Shells of Revolution
Authors: Clark R. A. , Reissner E. 
Published: June 2021

Abstract
The words “nearly cylindrical” are used in this paper to describe a thin elastic shell of revolution which is such that (a) the maximum variation of the radial dimension is small compared to the average radial dimension, and (b) the rate of change of the radial dimension with respect to the axial dimension is small compared to unity. For any particular type of loading a nearly cylindrical shell may or may not exhibit a behavior similar to that of a shell which is exactly cylindrical. The purpose of this paper is to demonstrate this fact and to present a method for obtaining approximate solutions for the stresses and deflections in either event. The method involves a perturbation procedure based on the assumption that all desired quantities can be represented as expansions in powers of two small parameters. The procedure leads to a set of linear differential equations with constant coefficients, which may be solved successively.
General Solutions of the Equations of Elasticity and Consolidation for a Porous Material
Authors: Biot M. A. 
Published: June 2021

Abstract
Equations of elasticity and consolidation for a porous elastic material containing a fluid have been previously established (1, 5). General solutions of these equations for the isotropic case are developed, giving directly the displacement field or the stress field in analogy with the Boussinesq-Papkovitch solution and the stress functions of the theory of elasticity. General properties of the solutions also are examined and the viewpoint of eigenfunctions in consolidation problems is introduced.
Analysis of Creep in Rotating Disks Based on the Tresca Criterion and Associated Flow Rule
Authors: Wahl A. M. 
Published: June 2021

Abstract
An analysis of creep deformations in rotating disks based on the Tresca criterion and the associated flow rule is presented. Assuming steady-state creep conditions and a creep rate equal to a function of stress times a function of time, the method is applied to the following cases: (a) Disk with constant thickness and constant temperature, (b) disk with variable thickness and constant temperature, and (c) disk with variable thickness and variable temperature. In many cases, the equations can be expressed in closed form. Comparison is made with test results on rotating disks at elevated temperature as reported in a previous paper. Based on certain stress-creep-rate relations, the method is also applied to the problem of calculating the transient change in stress when the stress distribution changes from an initial to a steady-state condition during the starting period. It is suggested that the simplification effected by the use of these methods may be of value for design purposes pending the development of more accurate methods based on test results.