bluuebunny/crossref_metadata_2025_split huggingface dataset:
A comparison between dehydrated and cryopreserved heterologous corneal grafts for penetrating keratoplasty in dogs and cats
Authors: Voitekha Mariia A. , Shilkin Aleksei G. 
Published: June 2021

AbstractObjectiveTo compare the efficacy of dehydrated and cryopreserved heterologous corneal grafts in the management of full‐thickness corneal defects in cats and dogs.Animals StudiedSixty‐five cats (81 eyes) and 42 dogs (51 eyes) with full‐thickness corneal defects of different origin.Materials and MethodsThis prospective randomized trial included 132 animal eyes (81 feline and 51 canine) with different full‐thickness corneal defects. Penetrating keratoplasty with cryopreserved and dehydrated corneal grafts was performed in 57 and 75 eyes, respectively. Follow‐up lasted for 6 months.ResultsOptically clear cornea with mild scarring was achieved in 40.4% of cases (23/57 eyes) after cryopreserved and in 42.7% of cases (32/75 eyes) after dehydrated corneal grafting. Moderate scarring after cryopreserved and dehydrated corneal grafting was observed in 35.1% of cases (20/57 eyes) and 37.3% of cases (28/75 eyes), respectively. Severe scarring and corneal opacities with severe vision loss after cryopreserved and dehydrated corneal grafting developed in 22.8% of cases (13/57 eyes) and 18.7% of cases (14/75 eyes), respectively. In two groups of animals combined, the affected eyes were salvaged and visual function improvement of varying degree was achieved in 78.0% of cases (103/132 eyes). Transplant rejection warranted enucleation in 1.75% of cases (1/57 eyes) and 1.3% of cases (1/75 eyes) after cryopreserved and dehydrated corneal grafting, respectively.ConclusionsNo statistically significant differences in clinical outcomes of penetrating keratoplasty with cryopreserved and dehydrated corneal grafts were observed. Dehydrated cornea may be considered a viable alternative to cryopreserved grafts for the management of full‐thickness corneal defects.
Clinical features and MRI characteristics of retinal detachment in dogs and cats
Authors: Stromberg Stephanie J. , Yan Jenny , Wisner Tristan G. , Wisner Erik R. , Good Kathryn L. 
Published: June 2021

AbstractThe aim of this retrospective observational study was to characterize the MRI appearance of retinal detachment (RD) in a sample of dogs and cats. Study inclusion was based on the following medical record criteria: (a) had a diagnosis of RD in at least one eye by either funduscopic examination or ocular ultrasound and had an MRI evaluation including the eyes, or (b) had a diagnosis of RD documented in an MRI report for at least one eye and also had a clinical eye examination. Eighteen patients (12 dogs, 6 cats) and 35 eyes met the inclusion criteria, although four eyes that were clinically examined could not be visualized funduscopically and did not have ocular ultrasound performed (criterion 2). The MRI and clinical diagnosis (via either funduscopy or ultrasound) of RD/no RD was concordant in 27 of 31 eyes (87%). Qualitatively, RD appeared as a variable intensity curvilinear structure located internal and adjacent to the sclera on all sequences and was best delineated on T2W sequences. RDs inconsistently contrast enhanced and, although there was no statistical difference, subjectively appeared more clearly delineated on dorsal and parasagittal images. In conclusion, findings from the current study support using MRI as an ancillary diagnostic test for confirmation or further characterization of RD in dogs and cats.
A Comprehensive Stability Criterion for Forced Vibrations in Nonlinear Systems
Authors: Klotter K. , Pinney E. 
Published: June 2021

Abstract
This paper deals with the forced vibrations described by the differential equation a q .. + c q + c Φ ( q , q . ) = P cos Ω t wherein Φ denotes a nonlinear function of q and/or q̇. It presents a criterion for determining their stability. It is shown that under very weak restrictions, which equivalently means, for a large variety of cases (including all of practical importance) the stability depends on the sign of ∂q*/∂P (q* denoting the maximum value of q(t) within a period). The motion is stable if this derivative is positive; it is unstable if it is negative.
The End Problem of Rectangular Strips
Authors: Horvay G. 
Published: June 2021

Abstract
J. Fadle was first to derive a solution for the stresses in a rectangular strip subject on one of its narrow edges to a self-equilibrating system of stresses; i.e., stresses which have zero resultant force and zero resultant moment. Fadle’s solution is rather unwieldy because of the use of complex (biharmonic) eigenfunctions. These eigenfunctions are associated with the roots of the equation sin 2γ ± 2γ = 0. The first (nonvanishing) root, as determined to seven decimals by Mittelman and Hillman, is γ2 = 2.1061961 + 1.1253643i. In this paper we derive a variational solution of the same problem in the form φ(x, y) = Σcnφn where, in first approximation, φn = fn(y)gn(x). The series Σcnfn(y) is obtained by expansion of the boundary values φ(0, y) of the Airy function φ into a complete set of self-equilibrating orthogonal polynomials fn(y); the functions gn(x) are then determined from the Euler-Lagrange equations of the associated variational problem. This procedure has the advantage of staying entirely in the real domain. The first approximation corresponds to the physical concept that the longitudinal fibers of the strip are beams on elastic foundation (the adjacent fibers furnish the elastic foundation) subject to end thrusts and lateral loads. Incidental to this idea there are provided quantitative formulas which relate depth of penetration of an applied traction to its shape (number of its wiggles). The eigenvalues γn, the real parts of which furnish the extinction coefficients, are obtained from a quadratic equation in γ2. One finds that the lowest (nonvanishing) eigenvalue is γ2 = 2.075 + 1.143i. In higher approximations coupling effects between derivatives of the orthogonal modes fngn are also taken into account. The jth approximation to a mode φn is obtained by evaluating a 2j − 1-rowed determinantal equation involving the functions fn−j+1 gn−j+1 to fn+j−1 gn+j−1. High modes are calculated with the same facility and accuracy as is the fundamental except that the fundamental mode φ2 not being preceded by other modes, requires, in jth approximation, only a j-rowed determinantal equation. One thus finds that in third approximation γ2 is the root of a 6th degree equation in γ2, and has the value γ2 = 2.1061964 + 1.1253644i.
On Turbulent Flow Between Parallel Plates
Authors: Pai S. I. 
Published: June 2021

Abstract
The Reynolds equations of motion of turbulent flow of incompressible fluid have been studied for turbulent flow between parallel plates. The number of these equations is finally reduced to two. One of these consists of mean velocity and correlation between transverse and longitudinal turbulent-velocity fluctuations u 1 ′ u 2 ′ ¯ only. The other consists of the mean pressure and transverse turbulent-velocity intensity. Some conclusions about the mean pressure distribution and turbulent fluctuations are drawn. These equations are applied to two special cases: One is Poiseuille flow in which both plates are at rest and the other is Couette flow in which one plate is at rest and the other is moving with constant velocity. The mean velocity distribution and the correlation u 1 ′ u 2 ′ ¯ can be expressed in a form of polynomial of the co-ordinate in the direction perpendicular to the plates, with the ratio of shearing stress on the plate to that of the corresponding laminar flow of the same maximum velocity as a parameter. These expressions hold true all the way across the plates, i.e., both the turbulent region and viscous layer including the laminar sublayer. These expressions for Poiseuille flow have been checked with experimental data of Laufer fairly well. It also shows that the logarithmic mean velocity distribution is not a rigorous solution of Reynolds equations.
Elastic Waves Created During Tensile Fracture: The Phenomenon of a Second Fracture
Authors: Miklowitz Julius 
Published: June 2021

Abstract
In some tensile tests with brittle materials, it was noted that fractures were produced at two different cross sections of the specimen when the rupture load was reached. The phenomenon of the second fracture prompted the present investigation. It is believed that the second fracture is caused by the destructive action of the elastic strain waves created during the first of the two fractures. The analytical and experimental work carried out was focused on describing the character of these waves. Consideration of the mechanics involved reduces the problem to that of a vibrating cantilever beam with time-dependent boundary conditions. Two types of waves are shown to exist. The first is a longitudinal unloading wave (compression). The other is a group of flexural strain waves caused by the moment that develops at the initial fracture section. The methods of operational mathematics and the electric-analog computer have been employed in the analytical study.
On the Maximum Numerical Value of the Tangential Stress in Thick-Walled Cylinders
Authors: Ranov T. , Park F. R. 
Published: June 2021

Abstract
Statements in the literature appear to imply that the numerical value of the circumferential stress in thick-walled cylinders is always a maximum at the inner radius. While this is certainly correct in the case of zero external pressure, the presence of both external and internal pressures creates the possibility of a numerically larger tangential stress occurring at the outer radius. This paper investigates this possibility and establishes a criterion for a check on the location of the numerical tangential stress maximum. A chart is presented for its convenient application.
On the Application of the Impedance Method to Continuous Systems
Authors: Chenea P. F. 
Published: June 2021

Abstract
It is shown how the concept of impedance may be extended to apply to those continuous systems whose vibratory behavior leads to the wave equation. The use of the method is demonstrated by three examples which include the free and forced vibration of an elastic bar in longitudinal oscillation and torsional oscillation of a tapered shaft.
Natural Frequencies of Twisted Cantilever Beams
Authors: Rosard D. D. 
Published: June 2021

Abstract
When a cantilever beam, an aircraft propeller, a turbine or compressor blade, is twisted, the natural frequencies of vibration may be changed appreciably. The effect of twist depends on the width-to-thickness ratio. An experimental and analytical investigation was made of the effect of twist for various width-to-thickness ratios.
The Shearing of a Rectangular Block Between Rough Plates
Authors: Craggs J. W. 
Published: June 2021

Abstract
In a recently published paper, W. T. Read gives an approximate solution of a problem in elasticity which occurs in the testing of materials. This is the problem of determining the stresses in a rectangular block when a pair of opposite faces are mutually displaced in the direction of an edge. The conditions are not those of uniform shear, for that would imply shear stresses on the free faces of the block. In the present paper an analytical solution of the same problem is obtained and the results are compared for a particular case. The method used is a particular case of the general method described by G. Pickett.
Bending of Circular and Ring-Shaped Plates on an Elastic Foundation
Authors: Reismann Herbert 
Published: June 2021

Abstract
This paper develops a method for the evaluation of deflections, moments, shears, and stresses of a circular or ring-shaped plate on an elastic foundation under transverse loads. A series solution is derived for plates subjected to edge and/or concentrated loads and is given in terms of tabulated functions. It is exact within the assumptions underlying the classical theory of plates and includes, as a particular case, the known solution of the corresponding radially symmetric problem. Two examples displaying radial asymmetry are worked. A solution is given for (a) a circular plate resting on an elastic foundation, clamped at the boundary and subjected to an arbitrarily placed concentrated load, and (b) a plate of infinite extent, resting on an elastic foundation and clamped to the boundary of a rigid circular disk to which a pure moment is applied.
Stress Concentration Due to a Hemispherical Pit at a Free Surface
Authors: Eubanks R. A. 
Published: June 2021

Abstract
This paper contains a solution in series form for the stresses and displacements around a hemispherical pit at a free surface of an elastic body. The problem is idealized by considering a semi-infinite medium which otherwise is bounded by a plane. At infinity the body is assumed to be in a state of plane hydrostatic tension perpendicular to the axis of symmetry of the pit. The present method of solution may be generalized to loadings which are not rotationally symmetric. Numerical results are given for the variation along the axis of symmetry of the normal stress which is parallel to the tractions at infinity; these results are compared with the known corresponding numerical values appropriate to the two-dimensional analog of the present problem.
Coulomb Friction, Plasticity, and Limit Loads
Authors: Drucker D. C. 
Published: June 2021

Abstract
Additional attention is given to the somewhat subtle but extremely important difference between Coulomb friction and the apparently corresponding resistance to plastic deformation. It is shown that the limit theorems previously proved for assemblages of perfectly plastic bodies do not always apply when there is finite sliding friction. Theorems are developed which relate the limit loads with finite Coulomb friction to the extreme cases of zero friction and of complete attachment, and also to the case where the frictional interfaces are “cemented” together with a cohesionless soil.
The Stresses in a Flat Curved Bar Resulting From Concentrated Tangential Boundary Loads
Authors: Wu Ning-Gau , Nelson C. W. 
Published: June 2021

Abstract
The Fourier integral method is applied to plane-stress problems of a curved bar bounded by two concentric circles and loaded by concentrated tangential boundary loads. The solutions presented may be combined with results given in previous papers (1, 2) dealing with radial boundary loads so as to obtain the stresses in a curved bar loaded by any combination of concentrated boundary loads inclined at any angle to the radial direction.
Forced Motions of Elastic Rods
Authors: Herrmann G. 
Published: June 2021

Abstract
In a recent paper by Mindlin and Herrmann, a one-dimensional theory of compressional waves in an elastic rod was described. This theory takes into account both radial inertia and radial shear stress and, accordingly, contains two dependent variables instead of the one axial displacement of classical rod theory. The solution of the equations for the case of forced motions thus involves complications not usually encountered. The difficulties may be surmounted in several ways, one of which is presented in this paper. The method described makes use of Lagrange’s equation of motion and reduces the most general problem of forced motion to a free vibration problem and a quadrature.
A Method for Determining the Internal Damping of Machine Members
Authors: Cochardt A. W. 
Published: June 2021

Abstract
A method is described by which the internal damping of a machine member can be evaluated in a simple way. It is shown that the results of a conventional damping test on a simple shaped specimen of the chosen material can be combined with a newly introduced quantity, the stress-distribution function, to yield the internal damping of a particular member. The suggested method eliminates the necessity for testing expensive specimens as was often the practice.
The Existence and Stability of Ultraharmonics and Subharmonics in Forced Nonlinear Oscillations
Authors: Caughey T. K. 
Published: June 2021

Abstract
A study is made of the forced oscillations of a second-order system having a small cubic nonlinearity in the restoring force. It is shown that under suitable conditions ultraharmonic or subharmonic motion exists in addition to the harmonic motion which a linearized theory would predict. By studying the stability of such motions it is shown that at points on the amplitude frequency-response curves having vertical tangents, instability and consequently “jumps” occur. A study of the dependence of the motion on the initial conditions reveals that while ultra-harmonic and harmonic motions are rather insensitive to initial conditions, the existence of subharmonic motion can be achieved only for a restricted set of initial conditions.
Application of the Electronic Differential Analyzer to the Oscillation of Beams, Including Shear and Rotary Inertia
Authors: Howe C. E. , Howe R. M. 
Published: June 2021

Abstract
The equations for normal modes of lateral vibration of beams are set up on the electronic differential analyzer. Beam deflections due to transverse shear and rotary-inertia forces are included. The differential analyzer is shown to be a fast and accurate method for solving the problem. Analyzer outputs include mode shape, slope, bending moment, and shear force along the beam. Curves showing the normal-mode frequencies for the first three modes of vibration of a uniform free-free beam are presented for a wide range of transverse shear and rotary-inertia parameters. The electronic differential analyzer also is utilized to solve the problem of lateral vibration of nonuniform beams.
Two-Dimensional Flow About Half Bodies Between Parallel Walls
Authors: Breslin John P. 
Published: June 2021

Abstract
Two new families of blunt half bodies are derived from the combination of source distributions and a uniform stream. One is obtained from a source lamina placed normal to an infinitely broad free stream, the other family is obtained by using the same source distribution between parallel walls. Formulas for the half-body profiles and the velocity and pressure distributions are given. Results of a calculation for selected values of the parameters are presented in graphical form and applications of the formulas are made to give the pressure distributions on the profile and the walls. The influence of the walls on the pressure distribution and body shape is studied. An approximate relationship (obtained by neglecting the small change in body shape for large wall distances) is derived for the half-body size which may be placed between given walls with a prescribed error in the pressure at one point of the profile. It is concluded that the influence of walls should be considered carefully in the design or use of two-dimensional facilities for study of flows which are of the half-body type.
Axially Symmetric Flexural Vibrations of a Circular Disk
Authors: Deresiewicz H. , Mindlin R. D. 
Published: June 2021

Abstract
At high frequencies, the flexural vibrations of a plate are described very poorly by the classical (Lagrange) theory because of neglect of the influence of coupling with thickness-shear vibrations. The latter may be taken into account by inclusion of rotatory inertia and shear-deformation terms in the equations. The resulting frequency spectrum is given, in this paper, for the case of axially symmetric vibrations of a circular disk with free edges and is compared with the spectrum predicted by the classical theory.
Clamped Semicircular Plate Under Uniform Bending Load
Authors: Woinowsky-Krieger S. 
Published: June 2021

Abstract
The semicircular plate subjected to bending usually is considered as a particular case of a sectorial plate and one introduces polar co-ordinates to discuss the deflection of the plate and the corresponding distribution of stresses. If the semicircular plate is clamped along the boundary the application of approximate methods becomes necessary to this end. It is worthy of note that a rather simple exact solution can be given in this latter case by making use of bipolar instead of polar co-ordinates.
Stress-Concentration Factors in Shafts With Transverse Holes as Found by the Electroplating Method
Authors: Ōkubo H. , Satō S. 
Published: June 2021

Abstract
In this paper the torsion of shafts with transverse holes has been investigated experimentally. Usual methods for stress measurements, such as the method of brittle coatings and the use of sensitive extensometers, are not applied effectively to the present problem because the maximum stress occurs in the bore and does not occur on the outer surface of the shaft. The stress may be measured by the stress-freezing and slicing method but we cannot expect too much from this method for the accurate determination of the stress when the diameter of the hole is comparatively small. In treating the problem theoretically, considerable mathematical difficulties are encountered on account of its axially nonsymmetrical nature. The electroplating method recently developed by one of the authors (1), however, has been proved to be useful in this case, so the maximum stresses in shafts are measured by this method and the stress-concentration factors are found for various diameters of the hole.
Laminar-Diffusion Boundary Layer—A Review
Authors: Berman Kurt 
Published: June 2021

Abstract
Diffusion theory has not assumed as yet the degree of organizational elegance accorded to fluid-flow and heat-transfer theories. In this paper mass-transport phenomena and their nondimensional correlation are summarized. In order that the similarities between energy, momentum, and mass-transport phenomena may be exhibited, the discussion of diffusion is preceded by brief summaries of dynamic and temperature boundary-layer theories.
Representation of Three-Dimensional Stress Distributions by Mohr Circles
Authors: Zizicas G. A. 
Published: June 2021

Abstract
O. Mohr has developed a diagram representing the normal stress component snn = σn and the total shearing stress component τn on an element of surface of any prescribed orientation with respect to the directions of the principal stresses. His procedure, however, does not give the orientation of the shearing stress τn within the element or, which is equivalent, the components of this shearing stress in a plane co-ordinate system within the element under consideration. An extension of the Mohr method that overcomes this limitation is presented in this note.
Heat-Transfer Measurements in an Inexpensive Supersonic Wind Tunnel: 1—Apparatus and Results for a Laminar Boundary Layer Based on a Simple One-Dimensional Flow Model
Authors: Kaye Joseph , Keenan J. H. , Brown G. A. , Shoulberg R. H. 
Published: June 2021

Abstract
Reliable experimental data, obtained at relatively low cost, are presented in the form of heat-transfer coefficients for air moving at supersonic speeds in a round tube. These data are analyzed, interpreted, and compared with available data in the literature. The experimental local heat-transfer coefficients are for laminar, transitional, and turbulent boundary layers. The data for a laminar boundary layer, comprising 17 runs, are discussed here for Mach numbers at tube inlet of 2.8 and 3.0. The range of values of diameter Reynolds number covered is from 20,000 to 100,000 for these laminar-flow tests, while the length Reynolds number extends to about 4,000,000. The computed quantities are obtained on the basis of a simple one-dimensional flow model, but a companion paper will analyze the same data in greater detail on the basis of a two-dimensional flow model.