bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evolution of a gradually abandoned Oligocene fluvial palaeovalley fill: Abu‐Roash area, north Western Desert, Egypt
Authors: Selim Selim Saber 
Published: June 2021

AbstractLittle is known about the evolution and gradual abandonment of the fluvial channel and associated sedimentary architecture preserved in the ancient sedimentary rock record. This research aims to analyze the changes and evolution of a gradually abandoned fluvial valley and associated within‐channel deposits and architecture from the rock record. This is achieved through detailed photogrammetry, outcrop sedimentology and quantification of palaeochannel parameters for the Oligocene palaeovalley fill of the north Western Desert basin of Egypt. The three‐dimensional vertical Oligocene outcrops and trenches of the study area provide the opportunity to analyze sedimentary facies, ichnology, architectural elements and evolution of the gradually abandoned fluvial channel belt. This paper presents a detailed model for the gradual abandonment and evolution of the fluvial palaeovalley through the stepwise transition from braided to meandering channel systems. This includes the transition from a bedload‐dominated, low sinuosity, braided channel that prominently features downstream‐accreted, mid‐channel and compound bars, to a small, mixed and suspended load‐dominated intermediate sinuosity (underfit) channel that is characterized by heterolithic‐dominated point bars, floodplain and mud‐plugs via a large, sand‐dominated, intermediate sinuosity channel with laterally accreted bars of transitional stage. The gradual abandonment of the fluvial palaeovalley is also associated with a successive decrease of the channel width and depth from >800 to 166 m and from 12 to 5 m, respectively. The successive abandonment is also associated with a gradual increase in the diversity and abundance of Scoyenia–Termitichnus ichnofacies groups, and vice versa in the Skolithos ichnofacies group. The successive decrease in channel width with gradual abandonment of the Oligocene palaeovalley is probably attributed to autogenic gradual avulsion, rather than allogenic. Comparison between the Oligocene palaeovalley fill and the modern analogues indicate the similarities in channel pattern changes and channel dimension through filling stages and differ from most modern counterparts because it is aggradational. This research enhances the understanding of the sedimentological characteristics and stratigraphic architecture of the gradually abandoned fluvial channels in the rock record and introduces insights for prediction of within‐channel facies and architectural heterogeneities of the fluvial channel reservoirs.
Finitude and the Precritical Imagination: Heidegger's Confrontation with Idealism in Kant and the Problem of Metaphysics and its Bearing on his Philosophy of Art
Authors: Phillips James 
Published: June 2021

AbstractHeidegger’s Kant and the Problem of Metaphysics (1929) turns on a reading of the productive imagination in the first edition of the Critique of Pure Reason (1781). In siding with the imagination, Heidegger declares his dissent from the neo‐Kantianism of his contemporaries. Yet, when Heidegger subsequently elaborates his philosophy of art in the 1930s, he is dismissive of the imagination altogether. His earlier partisanship was qualified. In Kant and the Problem of Metaphysics, Heidegger treats the productive imagination of Kant’s critical period as still a step short of Heidegger’s own problem of the time of finite human beings. German Idealism’s step past Kant is, for Heidegger, a step beyond, but in the wrong direction. The aesthetics of German Idealism builds on the unification of experience and conceptuality wrought by the productive imagination in its transcendental use, thereby inscribing in the work of art a neglect of finitude that Heidegger will dispute. If what Heidegger holds against the imagination is its transcendental use, the fully empirical concept of the imagination in Kant’s precritical writings invites reassessment in light of an engagement with finitude. I will show it has particular promise for rehabilitating the imagination in a Heideggerian philosophy of art.
Maintenance work: Interrogating the sociology of art
Authors: Darrow Sonya 
Published: June 2021

AbstractThe following article explores the different ways art sociologists investigate art that is based in the participatory arts. The aim is to shift the empirical focus to the art practice, which speaks for itself, and to place the work of the artist and all who cooperate or collaborate in the making of the artwork at the center of sociological analysis. By allowing the artist to speak fully about their work, art sociologists can uncover new social and cultural phenomena and better understand the different motivations underlying art‐making. The following literature highlights the recent tendencies in the sociology of art, explores the “social turn” in art and presents different sociologists who focus on the art practice and the art’s voice. For further development of the field, I suggest the sociology of art needs to catch‐up with the recent tendencies in art by placing the empirical focus on participatory art practices that will not only give us a better understanding about the intricate actions taking place in the art making, but it will also illuminate new layers of social life that are hidden. To conclude, I suggest that sociologists engage with participatory‐based artists to enhance sociology through a public sociology of art.
Treatment effects of the combination of ceftriaxone and valproic acid on neuronal and behavioural functions in a rat model of epilepsy
Authors: Li Hsin‐Hua , Lin Pin‐Jiun , Wang Wei‐Han , Tseng Li‐Ho , Tung Hsin , Liu Wen‐Yuan , Lin Chih‐Li , Liu Chiung‐Hui , Liao Wen‐Chieh , Hung Ching‐Sui , Ho Ying‐Jui 
Published: June 2021

New Findings
What is the central question of this study?
Imbalance of activities between GABAergic and glutamatergic systems is involved in epilepsy. It is not known whether simultaneously increasing GABAergic and decreasing glutamatergic activity using valproic acid and ceftriaxone, respectively, leads to better seizure control.
What is the central question of this study?
Ceftriaxone suppressed seizure and cognitive deficits and restored neuronal density and the number of newborn cells in the hippocampus in a rat model of epilepsy. Combined treatment with ceftriaxone and valproic acid showed additive effects in seizure suppression.
AbstractThe pathophysiology of epilepsy is typically considered as an imbalance between inhibitory GABA and excitatory glutamate neurotransmission. Valproic acid (Val), a GABA agonist, is one of the first‐line antiepileptic drugs in the treatment of epilepsy, but it exhibits adverse effects. Ceftriaxone (CEF) elevates expression of glutamate transporter‐1, enhances the reuptake of synaptic glutamate, increases the number of newborn cells and exhibits neuroprotective effects in animal studies. In this study, we evaluated effects of the combination of CEF and Val on behavioural and neuronal measures in a rat epilepsy model. Male Wistar rats were injected i.p. with pentylenetetrazol (35 mg/kg, every other day for 13 days) to induce the epilepsy model. Ceftriaxone (10 or 50 mg/kg), Val (50 or 100 mg/kg) or the combination of CEF and Val were injected daily after the fourth pentylenetetrazol injection for seven consecutive days. Epileptic rats exhibited seizure and impairments in motor and cognitive functions. Treatment with CEF and Val reduced the seizure and enhanced motor and cognitive functions in a dose‐dependent manner. The combination of CEF (10 mg/kg) and Val (50 mg/kg) improved behaviours considerably. Histologically, compared with control animals, epileptic rats exhibited lower neuronal density and a reduction in hippocampal newborn cells but higher apoptosis in the basolateral amygdala, all of which were restored by the treatment with CEF, Val or the combination of CEF and Val. The study findings demonstrated that the combination of low doses of CEF and Val has beneficial effects on seizure suppression, neuroprotection and improvement in motor and cognitive functions in epilepsy.
Topics in Gyroscopic Motion
Authors: Poritsky H. 
Published: June 2021

Abstract
After a brief review of the fundamental kinetic equations of gyroscope motion, the following topics are considered: (a) The erection of an electrically driven gyroscope when an electrical torque is applied. (b) The effect of inequality of the principal moments of inertia normal to the spin axis, on gyroscope motion. (c) The effect of inertia of the gimbals on motion of the gyroscope.
The Forced Oscillation of the Centrifugal Pendulum With Wide Angles
Authors: Crossley F. R. E. 
Published: June 2021

Abstract
The simple pendulum mounted to a rotor suffering torsional oscillation is used as an effective dynamic damper which may be tuned to any one harmonic order of vibration. The nonlinear equations of motion are here developed to investigate whether wider angles of swing, or whether larger or smaller sizes of pendulum relative to its carrier, are more effective. Resonance-type curves are drawn by assuming a single harmonic excitation and hyperelliptic pendulum motion without damping; it is shown that theoretically oscillations up to 90 deg may be used which are predictable, and that in all cases the tuning must be higher than that indicated by small-angle theory.
A Nondestructive Differential-Pressure Test for Thin Shells
Authors: New J. C. 
Published: June 2021

Abstract
The differential-pressure test is an original, nondestructive, experimental technique for determining incipient buckling pressures of thin shells subjected to external pressure. Extensions of the basic test permit study of many buckling parameters as well as other mechanical factors in thin-shell design and evaluation. The salient feature of the technique is the filling of the internal volume of the shell with a compressible fluid, such as water, to control the magnitude and rate of shell deformation. The incipient buckling pressure is detected by noting the point at which the difference in internal and external pressure becomes constant. Experimental verification of the technique and its nondestructive aspect is presented. Applications and limitations of the test are discussed.
Symmetric Turbulent Mixing of Two Parallel Streams
Authors: Torda T. P. , Ackermann W. O. , Burnett H. R. 
Published: June 2021

Abstract
The analysis of turbulent, incompressible, symmetric mixing of two parallel streams is presented. The influence of the upstream boundary layers on the mixing process is taken into account. The von Kármán integral concept is applied to a momentum and energy equation. These equations are used to evaluate the thickness of the mixing region and the velocity distribution in it. The results are presented in nondimensional form. A numerical illustrative example is given. Comparison with Tollmien’s analytical results and with experimental data of Liepmann and Laufer is made.
Influence Coefficients of Tapered Cantilever Beams Computed on SEAC
Authors: Levy Samuel 
Published: June 2021

Abstract
A description is given of a method for computing the influence coefficients in bending of a nonuniform cantilever beam using a basic code devised for the National Bureau of Standards electronic automatic computer SEAC. The given data for a particular problem are n, the number of stations at which influence coefficients are desired; EI0, EI1, … EIn, the bending stiffnesses at the root and at successive stations; and l1, l2, … ln, the distances between these stations. The basic code can be used in any case where the number of stations n is fewer than 23. In an example for a beam having 9 stations, the computing time was 3 min.
Axisymmetric Flexural Temperature Stresses in Circular Plates
Authors: Goldberg J. E. 
Published: June 2021

Abstract
The problem to be considered is that of determining the flexural stresses which result from temperature differences T between corresponding points on the upper and lower faces of circular plates (T = temperature at lower face minus temperature at upper face), when T is assumed to vary only with the distance from the center of the plate. This problem arises, for example, in the design of heated or cooled cylindrical processing tanks or vessels. In such cases, heat may be applied to the circular bottom of the vessel by a single concentric burner or heating element or by a ring of burners or elements, and the resulting temperature distribution will be approximately axisymmetric.
Some New Types of Orthotropic Plates Laminated of Orthotropic Material
Authors: Smith C. Bassel 
Published: June 2021

Abstract
Plywood plates are usually constructed so that the grain of adjacent plies is perpendicular. Such laminated plates possess two perpendicular axes of elastic symmetry. In this discussion plywood plates having other than 90 degree angles between the grain of adjacent plies are considered. First, a two-ply plate with the grain of one ply making any arbitrary angle with the grain of the other ply is discussed. It is shown that this plate, when in a state of plane stress or when subjected to small deflections, possesses the same two perpendicular axes of elastic symmetry. By making use of the formulas obtained for the two-ply plate, it is shown how to construct a plate of any number of plies (the adjacent plies not necessarily having their grain perpendicular) possessing the same type of elastic symmetry as the two-ply plate.
Graphical-Numerical Solution of Problems of Saint-Venant Torsion and Bending
Authors: Boley B. A. 
Published: June 2021

Abstract
A simple successive-approximations procedure for the solution of the problems of Saint-Venant torsion and bending of beams of arbitrary cross section is presented. The shear stresses in a cross section of the beam are first calculated from the formulas valid for thin-walled sections, on the basis of an assumed set of lines of shearing stress. From these a first approximation to the stress function of either the torsion or the bending problem is found. The second approximation to the stress function is then obtained from the governing equation of the problem, expressed in finite-difference form; this in turn allows the determination of an improved set of lines of shearing stress, and hence of the shearing stress itself. The procedure can be repeated until the results of two successive steps are sufficiently close. Applications are presented for a beam cross section for which the exact solutions are known, and it is shown that no further difficulties arise in applications to more complicated shapes.
The Application of Limit Analysis to Punch-Indentation Problems
Authors: Shield R. T. , Drucker D. C. 
Published: June 2021

Abstract
Limit analysis is applied to obtain upper and lower bounds for the punch pressure in the indentation of the plane surface of an elastic-perfectly plastic material by a flat rigid punch. The two-dimensional flat punch and the three-dimensional flat square and rectangular punch problems are considered. The analysis assumes Tresca’s yield criterion of constant maximum shearing stress k, during plastic deformation. It is shown that the pressure required to produce indentation in the two-dimensional problem lies between 5k and (2 + π)k. The lower bound obtained for any rectangular punch is again 5k while the upper bound for a smooth punch lies between 5.71k for a square and (2 + π)k for a very long rectangle. A value of 5.36k is found for a ratio of length to breadth of 3. The limit pressure for a uniformly loaded area, as distinguished from an area loaded by a punch, is bracketed by 5k and (2 + π)k when the area is convex.
Buckling of Multiple-Bay Ring-Reinforced Cylindrical Shells Subject to Hydrostatic Pressure
Authors: Nash W. A. 
Published: June 2021

Abstract
An analytical solution is presented for the problem of the elastic instability of a multiple-bay ring-reinforced cylindrical shell subject to hydrostatic pressure applied in both the radial and axial directions. The method used is that of minimization of the total potential. Expressions for the elastic strain energy in the shell and also in the rings are written in terms of displacement components of a point in the middle surface of the shell. Expressions for the work done by the external forces acting on the cylinder likewise are written in terms of these displacement components. A displacement configuration for the buckled shell is introduced which is in agreement with experimental evidence, in contrast to the arbitrary patterns assumed by previous investigators. The total potential is expressed in terms of these displacement components and is then minimized. As a result of this minimization a set of linear homogeneous equations is obtained. In order that a nontrivial solution to this system of equations exists, it is necessary that the determinant of the coefficients vanish. This condition determines the critical pressure at which elastic buckling of the cylindrical shell will occur.
Dynamic Behavior of Reinforced Cylindrical Shells in a Vacuum and in a Fluid
Authors: Junger Miguel C. 
Published: June 2021

Abstract
The vibrations of an infinite cylindrical shell reinforced with periodically spaced septa and stiffening rings are studied in a vacuum and in a fluid medium. Lagrange equations are used to derive the dynamic equations; the fluid reaction is obtained from the solution of the wave equation. The solution gives the dynamic characteristics of the shell, the amplitude of forced vibration, and the sound field generated thereby. The theory can be extended to shells embodying complex stiffening structures and load distributions. Certain features of the fluid reaction suggest interesting applications: Its inertial component becomes extremely large under certain conditions, thus tending to eliminate some modes of vibration; also, the resistive, i.e., damping, component may vanish for certain modes, which therefore do not radiate any sound.
Free and Forced Vibrations of an Infinitely Long Cylindrical Shell in an Infinite Acoustic Medium
Authors: Bleich H. H. , Baron M. L. 
Published: June 2021

Abstract
The paper presents a general method for the treatment of free and forced-vibration problems of infinitely long thin cylindrical shells. Surprisingly simple results are obtained by utilizing the known and tabulated modes of the shell in vacuo as generalized co-ordinates describing the response of the shell. The frequencies of free vibrations of submerged shells are obtained, and the response of the shell and medium to sinusoidally distributed, periodic, radial forces is determined. The results indicate that there is a low-frequency range where no radiation occurs and a high-frequency range where energy is radiated. Free vibration, or resonance in the case of forced vibrations, occurs only in the low-frequency range. The results of the paper may be applied to obtain the response to arbitrarily distributed, periodic, or nonperiodic forces by expanding such forces in Fourier series and/or integrals. The results for free and forced vibrations are discussed in general and for the specific case of steel shells in water. Tables are provided to facilitate numerical computations. With limitations the method is also applicable to ring-stiffened shells, and to the case of a static pressure in the surrounding medium.
Creep Tests of Rotating Disks at Elevated Temperature and Comparison With Theory
Authors: Wahl A. M. , Sankey G. O. , Manjoine M. J. , Shoemaker E. 
Published: June 2021

Abstract
A theoretical and experimental program involving methods of calculating creep in rotating disks at elevated temperatures is described. This program consisted primarily of the following: (a) Obtaining forged disks from the same ingot of 12 per cent chrome steel, all disks being forged and heat-treated in the same manner; (b) making spin tests at 1000 F on three of these disks for periods up to about 1000 hr; ( ) making long-time tension-creep tests at 1000 F on many specimens cut out circumferentially from several of the other disks at stresses approximating those of the spin tests; (d) investigating theoretical methods of calculation of creep deformation in such disks; and (e) comparison of spin-test results with those calculated theoretically using average tension-creep data. It was found that available methods of calculating rotating disks based on the Mises criterion gave creep deformations too low compared to the test values, i.e., on the unsafe side for design. Considerably better agreement between test and theoretical results is obtained if the latter is based on the maximum-shear theory. Some discussion is given of the reasons for the better agreement obtained using the latter theory; these are believed to be related in part to the anisotropy of the forged material tested. Further tests on other materials are necessary before general conclusions can be drawn; however, in the absence of test data it is suggested that a conservative course in design for such disks is to apply the maximum-shear theory.
On Bending of a Flat Slab Supported by Square-Shaped Columns and Clamped
Authors: Woinowsky-Krieger S. 
Published: June 2021

Abstract
A solution is given in this paper for the problem of bending of an infinite flat slab loaded uniformly and rigidly clamped in square-shaped columns arranged to form the square panels of the slab. The complex variable method in connection with conformal mapping is used for this aim. Although not perfectly rigorous, the solution obtained is sufficiently accurate for practical purposes and, besides, it can be improved at will. Stress diagrams traced in a particular case of column dimensions do not wholly confirm the stress distribution, generally accepted in design of flat slabs.
Influence Coefficients for Hemispherical Shells With Small Openings at the Vertex
Authors: Galletly G. D. 
Published: June 2021

Abstract
Three methods of obtaining the influence coefficients for a thin, constant-thickness, hemispherical shell with a circular opening at the vertex were investigated and utilized in a numerical example. Bearing in mind both accuracy and calculation time, it was concluded that when the total central angle subtended by the opening is less than approximately 30 deg, good results for the influence coefficient calculation will be obtained by using Method II in the text of the paper.
Buckling of Sandwich Cylinders Under Combined Compression, Torsion, and Bending Loads
Authors: Wang C. T. , Vaccaro R. J. , De Santo D. F. 
Published: June 2021

Abstract
A theoretical investigation is carried out on the buckling of sandwich cylinders under combined compression, torsion, and bending loads. The governing differential equation is solved by using Galerkin’s method. The interrelationship obtained between the critical loads is plotted in the form of nondimensional interaction curves. In the limiting cases of axial compression alone, torsion alone, bending alone, and combined bending and axial compression, the results agree with those obtained previously (1–3).
Forced Vibrations of a Body on an Infinite Elastic Solid
Authors: Arnold R. N. , Bycroft G. N. , Warburton G. B. 
Published: June 2021

Abstract
The paper considers the forced vibration of a rigid body resting on a homogeneous elastic medium of infinite surface area and constant depth which may be finite or infinite. Four modes of vibration for a body with a circular base are investigated; (a) vertical translation, (b) torsion, (c) horizontal translation, (d) rocking. For a semi-infinite medium the amplitude response can be obtained for any mass in terms of known constants of the system and two fundamental functions f1 and f2, which depend only on the exciting frequency and the properties of the medium. Close approximations to these functions have been evaluated for each mode. Experiments on an elastic model are described, the results of which are in good agreement with theoretical prediction. The behavior of a stratum of infinite area is more complex since functions f1 and f2 also depend on stratum depth. These functions have been evaluated for the torsional mode only, experimental results being given for the other modes.