bluuebunny/crossref_metadata_2025 huggingface dataset:
The Macrobrachium rosenbergii nodavirus: a detailed review of structure, infectivity, host immunity, diagnosis and prevention
Authors: Chen Ken Fong , Tan Wen Siang , Ong Lin Kooi , Zainal Abidin Syafiq Asnawi , Othman Iekhsan , Tey Beng Ti , Lee Ronald Fook Seng
Published: April 2021

The Macrobrachium rosenbergii nodavirus causes white tail disease, which primarily infects giant freshwater prawns, Macrobrachium rosenbergii. The infection leads to almost 100% mortality in post‐larvae, causing significant economic losses in aquaculture farms. To develop effective measures against outbreaks, a good understanding of the virus is essential. In this review, we discuss key aspects of the Macrobrachium rosenbergii nodavirus including its structure, mechanisms of transmission and infection and common strategies for detection and prevention of outbreaks. Structurally, cryogenic electron microscopy revealed that the nodavirus has a T = 3 icosahedral structure with dimeric blade‐like spikes on its surface. Homology modelling comparing wild‐type and enzymatically cleaved Macrobrachium rosenbergii nodavirus‐like particles revealed the significance of these spikes or protruding domains for binding. In vitro and in vivo studies have identified key aspects of Macrobrachium rosenbergii nodavirus infectivity, including (i) the viral binding targets such as transglutaminase and caveolin‐1, (ii) utilisation of B2‐like proteins in promoting infectivity and intracellular migration, (iii) replication mechanisms and (iv) co‐infection with the extra small virus. Though susceptible at a post‐larvae stage, adult Macrobrachium rosenbergii is immune to Macrobrachium rosenbergii nodavirus infection. During outbreaks, polymerase chain reaction and in situ hybridisation‐based detection techniques are commonly used to identify infected populations. Currently, the most useful strategies for an outbreak are physical biosecurity measures and prophylaxis such as vaccination and immunostimulants. Finally, critical gaps in research include development of immortalised shrimp cell models, elucidation of time‐resolved protein changes post‐infection and development of therapies to treat infections to mitigate economic losses during outbreaks.
Geology, mineralization and short wave infrared alteration mapping of the Khan Altai Au deposit, Mongolia
Authors: Iderbat Khaliunaa , Ganbat Mandalbayar , Densmaa Nyamdorj , Khashgerel Bat‐Erdene , Dashbaatar Davaa‐Ochir , Kavalieris Imants
Published: April 2021

Khan Altai Au deposit is located near the N margin of the Neoproterozoic‐Cambrian Lake terrain in SW Mongolia, about 5 km from its contact with the Proterozoic‐Archean Baydrag craton, and 18 km SE of the Khantaishir ophiolite, which was emplaced in the Late Cambrian. The host rocks are strongly deformed and metamorphosed to lower greenschist facies, and of uncertain age. They comprise a sequence of rhyolitic volcaniclastics and porphyritic flows interbedded with laminated siltstone, basaltic andesite and faulted against dolomite. Low‐grade gold mineralization (up to 2 ppm Au) is hosted mainly in rhyolitic volcanics and extends over an area of about 1,100 × 160 m with a vertical extent of about 200 m. It is associated with disseminated pyrite (2–10% by vol) but includes high‐grade zones (up to 183 ppm Au over 1 m) related to cm‐wide quartz‐native Au‐pyrite veins. The Au mineralized zone also encompasses VMS mineralization (currently of minor extent), characterized by massive pyrite‐sphalerite lenses and quartz‐chalcopyrite stringer zones. A larger VMS deposit (Ereen Budagt, about 10 Mt sulfide ore) is found 6 km to the SSE in a similar geological setting. The main alteration assemblage is quartz‐white mica‐albite, but with minor carbonate, chlorite, epidote‐actinolite and pyrophyllite‐diaspore‐dickite alteration. Gold mineralization is related to zones of strong tectonic foliation and formation of phengitic white mica, with an outward zonation to high Al white mica. Pyrite is typically euhedral, and exhibits concentric growth zones, as well as quartz pressure shadows to enclosing foliation, consistent with syngenetic growth during metamorphism and deformation. Other sulfides include arsenopyrite, sphalerite and possible marcasite. Preliminary LA‐ICPMS mapping shows pyrite rims are enriched in Au, As, Co, Cu, Ni, Pb, Ag, Mo and Se, the pyrite core is enriched in Co, Bi, Te, and rhyolitic host rock is enriched in K, Ba, V and Tl. Whole rock geochemistry of basaltic andesite to rhyolite, shows N‐MORB characteristics for basaltic andesite, as well as a subduction signature for all rocks, and high MgO (~8%), TiO2 (~1%) and low Ni, Cr content in basalt, compatible with a back arc tectonic setting.
Reconstructing the morphologies and hydrodynamics of ancient rivers from source to sink: Cretaceous Western Interior Basin, Utah, USA
Authors: Lyster Sinéad J. , Whittaker Alexander C. , Hampson Gary J. , Hajek Elizabeth A. , Allison Peter A. , Lathrop Bailey A.
Published: April 2021

Quantitative reconstruction of palaeohydrology from fluvial stratigraphy provides sophisticated insights into the response, and relative impact, of tectonic and climatic drivers on ancient fluvial landscapes. Here, field measurements and a suite of quantitative approaches are used to develop a four‐dimensional (space and time) reconstruction of palaeohydrology in Late Cretaceous palaeorivers of central Utah, USA – these rivers drained the Sevier mountains to the Western Interior Seaway. Field data include grain‐size and cross‐set measurements and span five parallel fluvial systems, two of which include up‐dip to down‐dip transects, across seven stratigraphic intervals through the Blackhawk Formation, Castlegate Sandstone and Price River Formation. Reconstructed palaeohydrological parameters include fluvial morphologies (flow depths, palaeoslopes, palaeorelief and planform morphologies) and various hydrodynamic properties (flow velocities, water discharges and sediment transport modes). Results suggest that fluvial morphologies were similar in space and time; median flow depths spanned 2 to 4 m with marginally greater flow depths in southerly systems. Meanwhile palaeoslopes spanned 10−3to 10−4, decreasing downstream by an order of magnitude. The most prominent spatio‐temporal change is an up to four‐fold increase in palaeoslope at the Blackhawk–Castlegate transition; associated alluvial palaeorelief is tens of metres during Blackhawk deposition and >100 m during Castlegate Sandstone deposition. This study observed no change in unit water discharges at the Blackhawk–Castlegate transition, which argues against a climatically driven increase in palaeoslope and channel steepness. These findings instead point to a tectonically driven palaeoslope increase, although one limitation in this study is uncertainty in palaeochannel widths, which directly influences total water discharges. These reconstructions complement and expand on extensive previous work in this region, which enables the efficacy of quantitative reconstruction tools to be tested. Comparison of results with facies‐based interpretations indicates that quantitative tools work well, but inconsistencies in more complex reconstructions (for example, planform morphologies) highlight the need for further work.
Mobilizing motherhood: The gendered burden of environmental protection
Authors: Cousins Elicia M.
Published: April 2021

Maternalist framing has been a consistent part of a long history of powerful, often successful organizing for environmental protection and justice. Yet today's calls on individuals to simultaneously engage in proenvironmental behavior and to protect themselves from environmental threats through consumption have mobilized maternal discourse in a way that is likely demobilizing in the long run. Indeed, the increasing individualization of the environmental movement is intersecting with persistent, unequal gendered structures of labor in a way that places the burden of environmentalism and environmental risk management on women and mothers. I argue that precautionary consumption and other forms of individualized environmental risk management add to the “third shift,” on top of the disproportionate burden of household labor and care work that women already face. This phenomenon is concerning because it has the potential to (1) limit women's engagement in other forms of environmental advocacy and leadership, and to (2) reproduce existing gender inequalities not only between men and women but alsoamongwomen of different levels of race and class privilege. Thus, the increasing individualization of the environmental movement also potentially exacerbates environmental injustice at the household level. Despite such emerging concerns, the domestic scale remains an often overlooked site of environmental harm and gendered burden.
Polymorphism analysis of candidate risk genes for pressure injuries in older Japanese patients: A cross‐sectional study at a long‐term care hospital
Authors: Tsukatani Toshihiro , Minematsu Takeo , Dai Misako , Tamai Nao , Nakagami Gojiro , Sugama Junko , Takada Chika , Sanada Hiromi
Published: April 2021

Advances in patient care for pressure injuries (PIs) have reduced the prevalence of PIs in Japan, although not in recent years. Several single‐nucleotide polymorphisms (SNPs) have been identified in genes potentially associated with PIs. However, individual variance among PI risks require targeted investigations that may lead to the identification of PI susceptibilities or preventive care options that directly influence PI development pathways. This cross‐sectional study examined the association between PIs and SNPs in genes related to tissue tolerance in patients in a long‐term care hospital in Japan. A total of 178 participants (130 control, 20 with superficial PI history, and 28 with deep PI history) were enrolled in this study of eight SNPs in hypoxia inducible factor 1 subunit alpha (HIF1A), vascular endothelial growth factor C (VEGFC), heat shock protein 90 alpha family class A member 1 (HSP90AA1), myostatin (MSTN), and vitamin D receptor (VDR). The primary outcome was a history of superficial and deep PIs in the last 6 months. SNPs were examined by real‐time polymerase chain reaction, followed by multivariate logistic regression analyses of the associations between the SNPs and PI history. The results showed a significant association between VEGFC rs1485766 and the history of superficial PIs (odds ratio = 2.95; 95% confidence interval = 1.07–8.11; p = 0.04). Stratified analysis using the Braden Scale (≤14) indicated a significant association between HIF1A rs11549465 and deep PIs (p = 0.04). Our study demonstrated that VEGFC rs1485766 and HIF1A rs11549465 were associated with superficial and deep PI susceptibilities, respectively.
GETTING TO KNOW A GOD YOU DO NOT BELIEVE IN: PANENTHEISM, EXTERNALISM, AND DIVINE HIDDENNESS
Authors: Cawdron Harvey
Published: April 2021

J. L. Schellenberg's hiddenness argument is one of the key contemporary justifications for atheism and has prompted numerous responses from those defending the plausibility of belief in God. I will outline a recent counterargument from Michael C. Rea, who claims that relationships with God are far more widely available than Schellenberg assumes. However, I will suggest that it invites a response from proponents of the hiddenness argument because it leaves some nonbelievers unaccounted for. I will rectify this by suggesting that a model of panentheism in which God is embodied in the cosmos allows all, including all nonbelievers, to have a relationship with God. I will then claim that semantic externalism and externalism about beliefs can enable nonbelievers to get to know this God. I will then challenge the hiddenness argument by suggesting that these relationships can accommodate the key motivations behind Schellenberg's insistence on personal relationships without requiring subjects to recognize that they are in a relationship with God.
Performance of the Viscously Damped Vibration Absorber Applied to Systems Having Frequency-Squared Excitation
Authors: Sauer F. M. , Garland C. F.
Published: April 2021

The effectiveness of the viscously damped vibration absorber is presented for the case in which the magnitude of the periodic exciting force acting upon the main system is proportional to the square of its frequency. Dimensionless expressions for the amplitudes of the main mass and absorber mass and for their phase relationships are derived as functions of frequency for three cases, namely, one in which the absorber is tuned to the natural frequency of the main system, one in which the absorber is tuned for maximum effectiveness over a wide range of forcing frequencies, and one in which the absorber is coupled to the main system by a viscous fluid only (the viscous Lanchester damper). The influence of main-system damping upon the amplitude of vibration of the main mass is shown for each case. Diagrams are presented showing the optimum damping, the maximum amplitude of the main mass, and the maximum relative amplitude between the main mass and absorber mass, as functions of the mass ratio. The performance of the absorber when applied to the system having velocity-squared excitation is compared with its performance when applied to the system having constant exciting force, published previously (1, 2). The tuning and damping for optimum performance are found to be different in the two cases. A model absorber with controllable tuning and damping, constructed for experimental work, is described and experimental data are presented for the case of most favorable tuning.
Stress Concentration Around a Triaxial Ellipsoidal Cavity
Authors: Sadowsky M. A. , Sternberg E.
Published: April 2021

Previous investigations have been concerned with the stress concentrations around internal cavities in the shape of an ellipsoid of revolution. This paper contains an exact closed solution, in terms of Jacobian elliptic functions, for the stress distribution around a general triaxial ellipsoidal cavity in an infinite elastic body. The body at infinity is in a uniform state of stress whose principal directions are parallel to the axes of the cavity, the magnitudes of the principal stresses at infinity being arbitrary. The solution covers as limiting cases the known results for spherical and spheroidal cavities. The technically important aspects of the ensuing stress concentration are discussed in detail.
Stability of Linear Oscillating Systems With Constant Time Lag
Authors: Ansoff H. I.
Published: April 2021

This paper discusses the influence of constant time delay in transmission of the control signal upon the output system of a closed-cycle control device. The use of Nyquist’s stability criterion permits investigation of the control signal proportional to any derivative of the displacement. The stability criteria are given in closed form.
Dynamic Capacity of Rolling Bearings
Authors: Lundberg Gustaf , Palmgren Arvid
Published: April 2021

This paper is a condensation of a comprehensive theory for fatigue failure in rolling bearings. The character of bearing fatigue failures is analyzed, and the effect of the volume of stressed material is assessed by means of modification of Weibull’s statistical theory of failure. The variables affecting bearing capacity are examined, and general formulas are set up relating the variables to the bearing capacity. Unknown exponents in the formulas are evaluated by means of extensive tests, and the final formulas are compared to experimental results.
Application of Electric-Analog Computers to Heat-Transfer and Fluid-Flow Problems
Authors: McCann G. D. , Wilts C. H.
Published: April 2021

There are two general classes of mathematical problems encountered in science and engineering for which high-speed mechanical computation is required. One of these embraces those problems of such complexity that it is impractical to obtain even a few solutions by conventional analysis. In the other class are problems which may be of only moderate complexity, but in which it is necessary to obtain a large number of solutions before the results become of practical value. It is the intent of this paper to discuss some of the applications that have been made of the California Institute of Technology “electric-analog computer” to heat-transfer and fluid-flow problems of both of the classes mentioned.
Compliance of Elastic Bodies in Contact
Authors: Mindlin R. D.
Published: April 2021

A small tangential force and a small torsional couple are applied across the elliptic contact surface of a pair of elastic bodies which have been pressed together. If there is no slip at the contact surface, considerations of symmetry and continuity lead to the conclusion that there is no change in the normal component of traction across the surface and, aside from warping of the surface, there is no relative displacement of points on the contact surface. The problem is thus reduced to a “problem of the plane” in which the tangential displacements and normal component of traction are given over part of the boundary and the three components of traction are given over the remainder. In the case of the tangential force it is observed that, when Poisson’s ratio is zero, the problem is a simple one, in potential theory, which is then generalized by means of a special device. An expression for tangential compliance is found as a linear combination of complete elliptic integrals. In general, the compliance is greater in the direction of the major axis of the elliptic contact surface than in the direction of the minor axis. Both components of tangential compliance increase as Poisson’s ratio decreases and become equal when Poisson’s ratio is zero. Over the practical range of Poisson’s ratio, the tangential compliance is greater than the normal compliance, but never more than twice as great as long as there is no slip. The tangential traction on the contact surface is everywhere parallel to the applied force. Contours of constant traction are ellipses homothetic with the elliptic boundary. The magnitude of the traction rises from one half the average at the center of the contact surface to infinity at the edge. Due to this infinity, there will be slip, the effect of which is studied for the circular contact surface. In the case of the torsional couple, the solution is obtained by generalizing a solution by H. Neuber pertaining to a hyperbolic groove in a twisted shaft. The torsional compliance is expressed in terms of complete elliptic integrals and, for the circular contact area, reduces to that found by E. Reissner and H. F. Sagoci. The resultant traction at a point rises from zero at the center to infinity at the edge of the contact surface, but is constant along and parallel to homothetic ellipses only in the case of the circular contact area.
Supersonic Flow Past Airfoil Tips
Authors: Beskin Leon
Published: April 2021

Airfoils examined in this paper are constituted by developable surfaces with arbitrary cross sections, all the generators of the surfaces, including the sharp leading and trailing edges, being supersonic. The tips are constituted by supersonic sections, which are generally blunt. The flow past an airfoil is determined by application of linearized equations, by means of Busemann’s conical flow theory. The two fundamental cases are that of a plate at a small angle of attack, and that of a slender wedge at zero angle of attack. In both cases, the supersonic leading edge and the subsonic tip may have arbitrary directions. The tip, particularly, may be either parallel to the flow, or acting as a leading edge, or else acting as a trailing edge, and each condition must be considered separately. All other conditions are solved by superposition of the two fundamental cases, antisymmetrical conditions resulting from the first case, and symmetrical conditions, from the second. Thus the general solution for the flow about a developable surface with arbitrary thickness and camber distributions, limited to a plane subsonic tip, is simply obtained under the conventional restrictions of the linear theory. While the absolutely general case of a developable surface, constituted by the tangents to an arbitrary edge of retrogradation, appears to be of limited interest, major applications correspond to special cases of developable surfaces; cylindrical, prismatical, conical, and pyramidal airfoils.
Discontinuities of Stress in Plane Plastic Flow
Authors: Winzer Alice , Carrier G. F.
Published: April 2021

This paper presents a method of discussing the stress distribution in the neighborhood of a surface of discontinuity of stress in a field of plane plastic flow. The plastic material under consideration is supposed to obey the laws of the Saint Venant-Mises theory; the surface of discontinuity is assumed to be plane, but the intensity of the discontinuity is allowed to vary along the trace of this plane in the plane of flow.
Vibration of Multifrequency Systems During Acceleration Through Critical Speeds
Authors: McCann G. D. , Bennett R. R.
Published: April 2021

This paper presents generalized solutions for the response of a linear two-degree-of-freedom system excited by a single constant-magnitude sinusoidal force whose frequency varies uniformly with time. These solutions were obtained with the Cal Tech “electric-analog computer” which is described briefly since it has wide application to problems of this type.
Transverse Vibration of a Two-Span Beam Under Action of a Moving Constant Force
Authors: Ayre R. S. , Ford George , Jacobsen L. S.
Published: April 2021

The problem relates to the transient vibration of a symmetrical, continuous, simply supported two-span beam which is traversed by a constant force moving with constant velocity. The beam is of slender proportions, flexure alone being considered. Damping is zero, and there is no mass associated with the moving force. Exact theoretical solutions for bending stress have been derived in general form. They consist of three infinite series, each related to one of three time eras as follows: (a) Where force is crossing first span; (b) is crossing second span; (c) has left the beam. Each term of a series is related to a natural mode of vibration. Quantitative theoretical studies show the variation in individual terms of the series, and also in summations of the first five terms, as the traversing velocity is varied. A mechanical model with electrical recording of stress was employed to obtain a more complete quantitative solution than was feasible analytically. The agreement between theory and experiment was reasonably good. Large magnifications of stress (of the order of 2.5) were found in the neighborhood of resonance with the fundamental mode.
Use of an Optical Property of Glycerine-Water Solutions to Study Viscous Fluid-Flow Problems
Authors: Hagerty W. W.
Published: April 2021

It is a property of certain concentrations of glycerine-water solutions, when in a state of steady flow, that the planes of equal shear in the liquid become visible in ordinary light, if viewed along a path tangent to the shear plane. This phenomenon has been used successfully to study a fluid-flow problem at the University of Michigan. The nature and scope of application of this optical property is currently being studied further. This report gives details of what may prove to be a useful tool in certain phases of experimental fluid-flow problems.
Stress Studies on Piping Expansion Bellows
Authors: Feely F. J. , Goryl W. M.
Published: April 2021

As a result of numerous and costly failures of the stainless-steel bellows used to take up thermal expansion in the piping of petroleum and chemical processing equipment, a basis has been developed for designing these bellows to operate within reasonable stresses. A formula has been derived to show the total stress induced in the material as a result of the combined effects of pressure and movement. The validity of the approximations used in this formula has been verified by laboratory strain-gage measurements on an experimental bellows. A relationship between several variables in the design of the disks has also been determined and serves as a basis for dimensioning them to achieve the most economical proportions. When this relationship is satisfied, the maximum permissible movement per disk can be obtained. This is shown graphically. Several supplementary formulas are given for determining bellows characteristics which may affect the design of adjacent piping. The problem of designing an expansion joint for high-pressure service is discussed briefly, and some preliminary laboratory data are presented on a commercial joint of this type.
An Approximate Solution for Incompressible Flow About an Ellipsoid Near a Plane Wall
Authors: Eisenberg Phillip
Published: April 2021

Using the method of successive images, an approximate solution for the velocity potential is obtained in closed form for incompressible flow about an ovary ellipsoid near a plane wall. The velocity distribution is computed from this solution in two ways. The first computation properly predicts differences in velocities on opposite half-meridians of the ellipsoid. A second method results in a symmetric velocity distribution but is useful for rapid estimates of the average wall effect. Pressure distributions calculated by this theory are compared with values measured on 4:1 and 6:1 ellipsoid models.
Free Periodic Motions of an Undamped Two-Degree-of-Freedom Oscillatory System With Nonlinear Unsymmetrical Elasticity
Authors: Soroka Walter W.
Published: April 2021

Precise solutions are presented for a two-degree-of-freedom oscillatory system containing a preset spring. Such a system is characteristic of an aircraft propeller-engine-supercharger installation. The periodic free motions obtained indicate the possibility of highly unconventional motions when the nonlinearity is pronounced, motions which may be easily overlooked in the usual approximate treatment of nonlinear systems. The results presented in this paper show that one mass may oscillate several times while the other mass is going through one oscillation. The ratio of oscillations of one mass with respect to the other changes with amplitude.

By considering the load-deflection curve for the nonlinear spring to be a broken line, periodic motions may be obtained to any desired degree of precision by combining conventional general solutions for two-degree-of-freedom linear systems.
A Method for Determining Mode Shapes and Frequencies Above the Fundamental by Matrix Iteration
Authors: Flomenhoft H. I.
Published: April 2021

Recently, an increasing use has been made of the matrix-iteration method for determining mode shapes and frequencies, particularly with regard to dynamic problems in aircraft design. Its particular advantage is the relative ease with which it handles complex discontinuous structures whose elastic properties can be defined adequately only in terms of influence coefficients. The disadvantage of tedious calculations has been alleviated greatly by an “acceleration method” for convergence which has been described by Isakson. The predominant disadvantage to matrix iteration, however, has been the difficulty in obtaining mode shapes and frequencies higher than the fundamental. The purpose of this paper is to establish a technique for accomplishing this in a manner that is practical for use in industry, as proved by its successful application to many problems of this type in the Aero-Elastic and Structures Research Laboratory at the Massachusetts Institute of Technology. This is accomplished by applying a device worked out by L. A. Pipes, and extending it to the general case, at the same time organizing the computations in tabular form. Only a basic knowledge of matrix notation and dynamic systems is necessary to understand this development, and this can be obtained easily by a review of von Kármán and Biot’s work on this subject.
Soap-Film and Sandbed-Mapper Techniques
Authors: Moore A. D.
Published: April 2021

A new photographic method for indirect measurement of a soap film is presented. Only one photograph is taken of a spiderweb grid as reflected by the film; the picture is analyzed to find contour lines and lines of maximum slope. Thus the film need last only long enough to be photographed. A fluid mapper of the isolated sandbed type is shown to be an analog for the soap film and, therefore, for the torsional stress situation in a shaft of like boundary. Thus sandbed techniques might replace soap-film techniques. The sandbed mapper also is an analog for other noncircular two-dimensional distributed source situations, such as the following: Field of a space charge; heat flow, with uniform heat production in the volume, the boundary being an isothermal; eddy currents in a plate (or section of lamination) uniformly pierced by a changing flux; magnetic flux in a volume of iron of constant permeability, the iron being (axially) a conductor of uniformly distributed current; streamline fluid flow in a long straight tube (sandbed isopressure lines corresponding to the tube’s isovelocity lines); and chemical diffusion, with the diffusing material uniformly appearing or disappearing throughout the volume. Since the sandbed is an analog for the soap film, the soap film is also an analog for these other situations.
Crushing of Aluminum Tubes Under Hydrostatic and Localized Pressure
Authors: Creutz E.
Published: April 2021

In the theory of elasticity equations have been derived by Sturm and Timoshenko for the crushing strength of long tubes subjected to external hydrostatic pressure. These equations have been found to fit experimental data on steel tubes, provided the length is several times the diameter, and the ratio of diameter to wall thickness exceeds about 30. No similar test data had been taken on aluminum tubes so an experimental study was carried out to determine whether the equations mentioned would apply. No satisfactory correlation was found to exist, but a simple equation was derived which is well within the reproducibility of the test results.
Impact on a Multispan Beam
Authors: Hoppmann W. H.
Published: April 2021

In this paper a study is made of impact on a continuous beam on four supports. The impact is produced by collision of a solid sphere with the beam at the mid-point of the center span. The spans are of equal length and of constant cross section. Formulas are obtained for the deflections and strains. A numerical example illustrating the theory is worked out in detail.
Characteristics of Irrotational Flow Through Axially Symmetric Orifices
Authors: Rouse Hunter , Abul-Fetouh Abdel-Hadi
Published: April 2021

Although an exact analytical solution of the orifice problem has not yet proved feasible, use of the method of relaxation has permitted a numerical determination of the flow characteristics to be made with sufficient precision for the problem to be considered solved. The coefficient of contraction is found to be practically identical with that evaluated by von Mises for two-dimensional flow from slots over the entire range of area ratio, and reasonable agreement is shown to exist between measurement and computation. Co-ordinates of the jet profiles are presented in tabular and graphical form, and are found to differ appreciably from those previously adapted from the two-dimensional case. A composite dimensionless chart is also provided showing the distribution of pressure along the boundary and center line and across the efflux section for the various area ratios.
Effect of Sinusoidally Varying Flow of Yield Stress Fluid on Heat Transfer From a Cylinder
Authors: Gupta S. , Patel S. A. , Chhabra R. P.
Published: April 2021

The effect of pulsating laminar flow of a Bingham plastic fluid on heat transfer from a constant temperature cylinder is studied numerically over wide ranges of conditions as Reynolds number (0.1 ≤ Re ≤ 40) and Bingham number (0.01 ≤ Bn ≤ 50) based on the mean velocity, Prandtl number (10 ≤ Pr ≤ 100), pulsation frequency (0 ≤ ω* ≤ π), and amplitude (0 ≤ A ≤ 0.8). Results are visualized in terms of instantaneous streamlines, isotherms, and apparent yield surfaces at different instants of time during a pulsation cycle. The overall behavior is discussed in terms of the instantaneous and time-averaged values of the drag coefficient and Nusselt number. The size of the yielded zone is nearly in phase with the pulsating velocity, whereas the phase shift has been observed in both drag coefficient and Nusselt number. The maximum augmentation (∼30%) in Nusselt number occurs at Bn = 1, Re = 40, Pr = 100, ω* = π, and A = 0.8 with respect to that for uniform flow. However, the increasing yield stress tends to suppress the potential for heat transfer enhancement. Conversely, this technique of process intensification is best suited for Newtonian fluids in the limit of Bn → 0. Finally, a simple expression consolidates the numerical values of the time-averaged Nusselt number as a function of the pertinent dimensionless parameters, which is consistent with the widely accepted scaling of the Nusselt number with ∼Pe1/3 under these conditions.
The Past and Future of the Monte Carlo Method in Thermal Radiation Transfer
Authors: Howell John R. , Daun Kyle J.
Published: April 2021

Since its initial development as a specialty technique for modeling neutron transport in fissile materials almost 80 years ago, the Monte Carlo method has since been deployed in almost every area of science and engineering, including radiative transfer. This paper reviews the history and progress in Monte Carlo methods for simulating radiative energy transfer, with emphasis on advances over the past 25 years. A short historical review that emphasizes the probabilistic foundations of the method, is followed by discussions of recent extensions and applications, including variance reduction techniques, high fidelity simulations in complex media, and a discussion of unresolved issues. The article concludes with an outlook for the method as impacted by advancements in algorithm development as well as massively parallel and quantum computing.
Optimization-Driven Controller Design for a High-Performance Electro-Hydrostatic Asymmetric Actuator Operating in All Quadrants
Authors: Butt Khurram , Costa Gustavo Koury , Sepehri Nariman
Published: April 2021

This paper presents an optimization-driven controller design for smooth and accurate position control of a single-rod electrohydrostatic actuator. The design approach uses logically guided iterative runs of the electrohydrostatic actuator to determine the optimal gain and poles' locations of a low-bandwidth controller. The optimization algorithm used in the paper is the globalized bounded Nelder–Mead algorithm with deterministic restarts for improved globalization and lower numerical cost. The design also incorporates a prefilter to ensure minimum jerk in the system's step input response in the beginning and while approaching steady-state. The step response of the filter is a seventh-deg polynomial curve that ensures the minimum change in acceleration in both states. Experimental results reveal that the addition of the proposed prefilter reduces jerk in the system by up to 90%. Results also indicate that the controller performs very well in all quadrants with external load uncertainty of up to 367 kg and thus proves the effectiveness of the design approach.
Evaluation of the Kinematic Biofidelity and Inter-Test Repeatability of Global Accelerations and Brain Parenchyma Pressure for a Head–Brain Physical Model
Authors: Li Yizhao , Ouellet Simon , Vette Albert H. , Raboud Don , Martin Ashton , Dennison Christopher R.
Published: April 2021

Head surrogates are widely used in biomechanical research and headgear assessment. They are designed to approximate the inertial and mechanical properties of the head and are instrumented to measure global head kinematics. Due to the recent interest in studying disruption to the brain, some head models include internal fluid layers and brain tissue, and instrumentation to measure head intracranial biomechanics. However, it is unknown whether such models exhibit realistic human responses. Therefore, this study aims to assess the biofidelity and repeatability of a head model, the Blast Injury Protection Evaluation Device (BIPED), that can measure both global head kinematics and intraparenchymal pressure (IPP) for application in blunt impact, a common loading scenario in civilian life. Drop tests were conducted with the BIPED and the widely used Hybrid III headform. BIPED measures were compared to the Hybrid III data and published cadaveric data, and the biofidelity level of the global linear acceleration was quantified using CORrelation and Analysis (CORA) ratings. The repeatability of the acceleration and IPP measurements in multiple impact scenarios was evaluated via the coefficient of variation (COV) of the magnitudes and pulse durations. BIPED acceleration peaks were generally not significantly different from cadaver and Hybrid III data. The CORA ratings for the BIPED and Hybrid III accelerations ranged from 0.50 to 0.61 and 0.51 to 0.77, respectively. The COVs of acceleration and IPP were generally below 10%. This study is an important step toward a biofidelic head surrogate measuring both global kinematics and IPP in blunt impact.
The Design and Development of an Eye Drop Aid for Glaucoma Patients
Authors: Srihirun Janyut , Poowaruttanawiwit Prayuth
Published: April 2021

Visual impairment is an important public health problem. A cataract is the most common eye disease, and surgical methods are mostly used. Unlike a cataract, glaucoma may lead to permanent loss of vision and can be treated appropriately using eye drops. In this study, the researchers aimed to create, design, and develop a device called “Eye Drop Aid of Naresuan University (EDANU).” This research employed mixed methods using an in-depth interview and questionnaire, which were conducted with a group of 10 experts to provide preliminary data for the design and a group of 20 volunteers to test the efficacy and safety of the EDANU compared with the instructions of the Xal-Ease™ eye drop administration and instructions as recommended by the Pharmacy Council of Thailand in the laboratory. It was found that the EDANU, which was designed and developed as a prototype using thermoplastic polyurethane, which is a highly flexible material, was more accurate, reliable, and safer than the Xal-Ease eye drop administration. The EDANU displayed efficient statistical significance and proved to be safe for using in the laboratory.This was a device that could help glaucoma patients and their caregivers have a better quality of life because this device was more accurate, reliable, and safer than the other two methods. However, the EDANU is still in the process of prototype development, and, in the future, it would still be necessary to study with a human clinical trial.
An Artificial-Intelligence and Machine-Learning-Based Methodology to Conduct Seemingly Strain-Controlled Fatigue Test in a Pressurized-Water-Reactor-Test-Loop-Autoclave, While Not Controlling the Strain
Authors: Mohanty Subhasish , Listwan Joseph T.
Published: April 2021

In general, low cycle fatigue analysis of pressurized water reactor (PWR) components, requires strain-controlled fatigue test data such as using strain versus life (ε–N) curves. Conducting strain-controlled fatigue tests under in-air conditions is not an issue. However, controlling strain in a PWR-test-loop-autoclave is a challenge, since an extensometer cannot be placed in a narrow autoclave (typically used in a high-temperature-pressure PWR-test-loop). This is due to lack of space inside an autoclave that houses the test specimen. In addition, installing a contact-type extensometer in the path of a high-pressure flow can be a challenge. These difficulties of using an extensometer inside an autoclave led us to use an outside-autoclave displacement sensor which measures the displacement of pull-rod-specimen assembly. However, in our study (based on in-air fatigue test data), we found that a pull-rod-controlled based fatigue test can lead to substantial cyclic hardening/softening resulting in substantially different cyclic strain amplitudes and their rates compared to the desired cyclic strain amplitudes and its rates. In this paper, we propose an Artificial-Intelligence and Machine-Learning based technique such as using k-means clustering technique to improve the pull-rod-control based fatigue test method, such that the gage-area strain amplitude and rates can reasonably be achieved. In support of this, we present the fatigue test results for both 316 SS base and 81/182 dissimilar-metal-weld specimens.
A Study of Human Balance and Coordination Using a Head Mounted Display
Authors: Gracia De Luna Daniel , Tijernia Roel , Butler Alley , Tomai Emmett , Timmer Douglas , Caruntu Dumitru I.
Published: April 2021

This paper reports on an experiment in human subject balance and coordination using a HTC Vive head mounted display to create a virtual environment. For the experiment, 30 male human subjects of college age and 30 female subjects of college age were asked to navigate along a clear path in a virtual world using a controller with their dominant hand and asked to balance a virtual ball on a virtual plate using the other controller in the non-dominant hand. The test subjects moved along a clearly marked path, with three surprise obstacles occurring: a large rock landing near the path, and explosion near the path, and a flock of birds coming across the path. Data included 6 degree of freedom trajectories for the head, and both hands, as well as data gathered by the computer system on ball location and velocity, plate location and velocity and ball status. Likert scale questionnaires were answered by the test subjects relative to video game experience, sense of presence, and ease of managing the ball movement. Statistics showed that the male students dropped the ball less frequently at p = 0.0254 and p = 0.0036. In contrast, female students were aware of their performance with correlation levels of 0.632 and 0.588.
Effects of Pulmonary Fibrosis and Surface Tension on Alveolar Sac Mechanics in Diffuse Alveolar Damage
Authors: Chen Long , Tao Weiwei , Ji Wei , Lu Yan , Zhao Xia
Published: April 2021

Diffuse alveolar damage (DAD) is a characteristic histopathologic pattern in most cases of acute respiratory distress syndrome and severe viral pneumonia, such as COVID-19. DAD is characterized by an acute phase with edema, hyaline membranes, and inflammation followed by an organizing phase with pulmonary fibrosis and hyperplasia. The degree of pulmonary fibrosis and surface tension is different in the pathological stages of DAD. The effects of pulmonary fibrosis and surface tension on alveolar sac mechanics in DAD are investigated by using the fluid–structure interaction (FSI) method. The human pulmonary alveolus is idealized by a three-dimensional honeycomb-like geometry, with alveolar geometries approximated as closely packed 14-sided polygons. A dynamic compression-relaxation model for surface tension effects is adopted. Compared to a healthy model, DAD models are created by increasing the tissue thickness and decreasing the concentration of the surfactant. The FSI results show that pulmonary fibrosis is more influential than the surface tension on flow rate, volume, P–V loop, and resistance. The lungs of the disease models become stiffer than those of the healthy models. According to the P–V loop results, the surface tension plays a more important role in hysteresis than the material nonlinearity of the lung tissue. Our study demonstrates the differences in air flow and lung function on the alveolar sacs between the healthy and DAD models.
Ticks (Acari: Ixodidae) of Tapirus bairdii (Perissodactyla: Tapiridae) and notes on Amblyomma coelebs feeding on human, at Indio Maiz Biological Reserve, Nicaragua

Authors: Espinoza Jeffrey Arana , Jordan Christopher , Ans Darmando , Martins Thiago F. , C. Sergio Bermúdez
Published: April 2021

During tapir capture expeditions in Indio Maiz Biological Reserve, southeast Nicaragua, ticks were collected from free range Baird’s tapir (Tapirusbairdii) were collected. 91 Ixodidae ticks were collected from seven tapirs, corresponding to Amblyomma coelebs, Amblyomma cf. oblongoguttatum, and Amblyomma ovale. In addition, six adults of A. coelebs were found on a person. This paper represents the first finding of Ixodidae in T. bairdii of Nicaragua, and the first indication of A. coelebs as a human parasite in Nicaragua.
A deep learning approach for the fast generation of acoustic holograms
Authors: Lin Qin , Wang Jiaqian , Cai Feiyan , Zhang Rujun , Zhao Degang , Xia Xiangxiang , Wang Jinping , Zheng Hairong
Published: April 2021

Acoustic holographic techniques are crucial in diverse applications, such as three-dimensional holographic display and particle manipulation. However, conventional methods for computer-generated acoustics holography rely heavily on iterative optimization algorithms, which are time-consuming and particularly hinder their capacity of generating a dynamic hologram in real time. Here, a deep learning approach based on U-Net is proposed to rapidly generate an acoustic hologram with optimal amplitude and phase maps. It is demonstrated that, after being trained with adequate data that are numerically synthesized by the pseudo-inverse method, the proposed deep learning approach can generate both amplitude and phase maps for new target images with an improved overall reconstruction quality. Remarkably, after the offline cost is compensated by a lower online cost for the proposed DL approach, the hologram generation speed is significantly accelerated by the proposed deep learning approach as compared with the pseudo-inverse method, especially for complicated or dynamic images. With the hierarchical feature learning capability and the fast online computational speed, the proposed deep learning approach can serve as a smart platform for rapidly generating complete maps of holograms for the sophisticated or dynamical target images, leading to the new possibility of real-time acoustic-hologram-based applications.
Associations Between Physical Activity Enjoyment and Age-Related Decline in Physical Activity in Children—Results From a Longitudinal Within-Person Study
Authors: Haas Petra , Yang Chih-Hsiang , Dunton Genevieve F.
Published: April 2021

Physical activity declines from childhood to adolescence. Affective factors may partially account for this decline. The present study investigated whether within-person changes in children’s enjoyment of physical activity are associated with the age-related decline in physical activity. Children (N = 169, 54% female, 56% Hispanic; 8–12 years old at enrollment) took part in a longitudinal study with six assessment waves across 3 years. At each wave, enjoyment of physical activity was reported, and moderate to vigorous physical activity (MVPA) was measured with an accelerometer across seven consecutive days. MVPA and enjoyment of physical activity both declined across waves. Multilevel analyses revealed that within-person changes in enjoyment moderated the effects of age on within-person changes in MVPA. Enjoyment appeared to be a dynamic factor that buffered against the age-related decline in physical activity in youth. These findings call for health promotion interventions that encourage enjoyable physical activities.
Minimally invasive electroceutical catheter for endoluminal defect sealing
Authors: Singh Manisha , Varela Claudia E. , Whyte William , Horvath Markus A. , Tan Nigel C. S. , Ong Chee Bing , Liang Patric , Schermerhorn Marc L. , Roche Ellen T. , Steele Terry W. J.
Published: April 2021

A catheter-based device activates voltage-curable adhesives in situ for minimally invasive closure of vascular lumen defects.
Atypical is the new norm, for B cells and the rest of us
Authors: Williams Adam , Eisenbarth Stephanie C.
Published: April 2021

An unusual form of activated B cells in adults is described, called atypical B cells, both in the steady state and after vaccination.