bluuebunny/crossref_metadata_2025 huggingface dataset:
Local Pressure Measurement of Gaseous Flow Through Microchannels
Authors: Turner Stephen E. , Sun Hongwei , Faghri Mohammad , Gregory Otto J.
Published: December 2021

This paper presents an experimental investigation on nitrogen and helium flow in microchannels etched in silicon with hydraulic diameters of 9.7, 19.6, and 46.6 μm, and Reynolds numbers ranging from 0. 2 to 1000. The objectives of this research are (1) to measure the pressure distribution along the length of a microchannel; and (2) to determine the friction factor within the fully developed region of the microchannel. The pressure distribution is presented as absolute local pressure plotted against the distance from the microchannel inlet. The friction factor results are presented as the product of friction factor and Reynolds number plotted against Reynolds number with the outlet Knudsen number, Kn, as a curve parameter. The following conclusions have been reached in the present investigation: (1) Pressure losses at the microchannel entrance can be significant; (2) the product, f*Re, when measured sufficiently far away from the entrance and exit is a constant in the laminar flow region; and (3) the friction factor decreases as the Knudsen number increases.
Microscale Heat Conduction in Dielectric Thin Tubes
Authors: Sheu Long-Jye , Lin Jenn-Der , Chou Fu-Chu
Published: December 2021

The radial heat conduction in the tube wall of dielectric thin tubes is studied in this work. An equation of phonon radiative transfer (EPRT) is used in association with nodal approximation technique for examining the heat transport in the thin tubes. The effective thermal conductivity of thin tubes is calculated based on the heat flux in the middle surface of the tubes. Results indicate that the energy distribution in the annulus is dominated by phonons excited by outer surface. Consequently, the temperature distribution is considerably affected by the temperature of outer surface. In addition to tube wall thickness, R2-R1, which was usually considered as the size effect on heat conduction, the curvature effect would significantly change the heat flux across the tube wall and consequently affect the effective thermal conductivity.
Analysis of Heat Transfer During Quenching of a Gear Blank
Authors: Sahai Vivek , Aceves Salvador M.
Published: December 2021

This paper presents experimental and numerical results for the quench of a gear blank in agitated and stagnant oil. Temperatures within the gear blank are determined with a whole domain-optimizer technique inverse solution method, to calculate the time history at every point in the gear blank. The development of this procedure represents the first stage in an overall analysis of the quench process that will later include material phase transformations and deformation.

The paper presents ten variations in setting up the inverse problem, to analyze which combination of independent variables and decision variables results in the best match between experimental and numerical results. The results indicate that dividing the boundary of the gear blank into four zones and assigning a fixed heat transfer coefficient or heat flux to each zone yields an average RMS error (average difference between experimental and numerical results) of the order of 40 K. This error can be reduced by either increasing the number of zones, by reducing the number of thermocouples being matched, or by allowing the heat transfer or heat flux to vary within the zones. Of these possibilities, variation of heat transfer within the zones gives the best improvement in the quality of the match for the amount of extra computational effort required to run the problem.
Visualization and Measurements of Picoliter-Size Molten Droplet Impact Dynamics and Solidification on a Surface
Authors: Attinger D. , Zhao Z. , Poulikakos D.
Published: December 2021

The basic problem of the impact and solidification of molten solder droplets on a flat substrate is of central importance to the novel micromanufacturing process of solder jetting, in which microscopic size solder droplets are dispensed for the attachment of microelectronic components. Under certain conditions, “frozen ripples” appear on the surface of solidified solder microbumps deposited using the solder jetting technology (Waldvogel et al. 1996). The mechanism for the formation of these “frozen ripples” was later explained and quantified in a theoretical study by Waldvogel and Poulikakos (1997) as a consequence of the dynamic competition between flow oscillations and rapid solidification. However, no analogous experimental results for the transient impact process have been reported to date to the best of our knowledge. Such a study is reported in this paper. Eutectic solder (63Sn37Pb) was melted to a preset superheat and used in a specially designed droplet generator to produce droplets with diameters in the range 50–100 μm. The size, temperature, and impacting speed of the molten droplets were maintained constant. The primary variable is the temperature of the substrate that was controlled in the range from 48 °C to 135 °C. The dynamics of molten solder microdroplet impact and solidification on the substrate was investigated using a flash microscopy technique. The duration of flash used in the study was 1 μs. The time for the completion of solidification from the moment of a solder droplet impact on the substrate varies between 150 μs and 350 μs. The dynamic interaction between the oscillation in the liquid region and the rapid advance of solidification front was visualized, quantified and presented in this paper. To the best of our knowledge, this study presents the first published experimental results on the transient fluid dynamics and solidification of molten microdroplets impacting on a substrate at the above mentioned time and length scales that are directly relevant to the novel solder jetting technology. Existing results on this problem pertain to time and length scales at least one order of magnitude higher (Jonas et al. 1997; Pasandideh-Fard et al. 1998; Zhao et al. 1996). The visualization results on the oscillatory motion and rapid solidification shed light on a host of interesting phenomena and also support the frozen ripple formation theory presented by Waldvogel and Poulikakos (1997).
Investigation of Thermal Conductivity of a Polymer Solution as Function of Shearing Rate
Authors: Kostic Milivoje , Tong Haibo
Published: December 2021

A novel research apparatus is developed to measure the fluid thermal conductivity while in shearing flow, and to determine its dependence on the shearing itself, contrary to the current state-of-the-art of measuring thermal conductivity under the condition of motionless fluid.

A concentric cylinders’ apparatus was developed to provide controlled heat transfer in the radial direction, orthogonal to the circumferential fluid velocity, thus virtually preserving pure conductive heat transfer mode. The measurement and control are accomplished and integrated by using a computerized data acquisition system and a comprehensive virtual instrument, developed using the LabVIEW application software.

It was found that the thermal conductivity of a Newtonian fluid, such as distilled water, was virtually independent of the fluid motion, as expected. However, for non-Newtonian fluids such as 1000 and 2000 wppm aqueous polyacrylamide (Praestol) solutions, there was up to 10–20% increase of thermal conductivity in the operating shear rate range (40 ≤ γ ≤ 510 sec−1) at 27°C average fluid temperature.
Performance and Modeling of Heat Flux Sensors in Different Environments
Authors: Holmberg D. G. , Womeldorf C. A.
Published: December 2021

Heat flux measurement is not simple; care is required in selecting a suitable sensor for a given application. Surface substrate properties and the convective and radiative environment determine the choice of sensors. Mounting of the sensor, especially in calibration versus application, influences accuracy of measurement. The purpose of the present study is to increase awareness of potential errors in heat flux sensor use. This paper compares sensor performance in general by examining results of testing three commercially available sensors and by numerical modeling of these sensors. Comparisons of sensor calibrations in the NIST convective heat flux calibration facility are made with manufacturer calibrations and give evidence of potential pitfalls when using a sensor in a different environment than the calibration environment. Modeling results help explain observed data, demonstrating specific sensor parameters that can lead to significantly different calibrations in different environments.
Influence of Non-Isothermal Button Gage Surface Temperature in Heat Flux Measurement Applications
Authors: Zilles David A. , Abhari Reza S.
Published: December 2021

Button gages have been extensively used to measure convective heat transfer coefficients in a number of short duration experiments. A button gage consists of a small insert made from an insulator material, typically Pyrex, with a thin film of Platinum active element painted on its surface. In a typical short duration experiment, gages are initially at the same temperature as the test article. As the flow is established, convective heat flux results in the surface temperature of the gage to rise much more rapidly than the surrounding metal walls. The influence of this non-isothermal wall condition on the local thermal boundary layer and hence the measured data is the focus of the present program.

A detailed experimental study of the influence of local non-isothermal conditions on the inferred heat flux from button heat-flux gages is performed. An existing wind tunnel capable of generating subsonic through transonic flow conditions has been modified to include an isothermal flat plate test section with a row of surface flush-mounted button heat-flux gages. In addition to the button gages, a uniform sheet of two-layered Kapton heat-flux gages, operating under isothermal conditions, are also applied to the flat plate surface. A detailed study of the uncertainties of experimental results is performed. As part of this study, flow Mach number and Reynolds number are varied and their relative significance upon the deviation in the response of the gages is quantified. The measured heat flux did show a deviation from the isothermal measured values. It is further shown that a correction term based on classical heat transfer theory will adjust the measured heat flux on the flat plate to match isothermal values for a range of Reynolds numbers and temperature ratios.
A Numerical Evaluation of a Simple Procedure for Using Transient Surface Temperature Measurements to Determine Local Convective Heat Transfer Rates
Authors: Oosthuizen Patrick H. , Naylor David
Published: December 2021

A transient method, based on an inverse heat conduction solution, for experimentally determining the distribution of local heat transfer rates on the surface of a body has been numerically evaluated. The particular interest is in situations in which the heat transfer coefficients are relatively low and in which there are relatively large changes in the heat transfer coefficient over the surface of the body being considered. In the method, a solid body of the shape being investigated, constructed from a low conductivity material, is heated to a uniform temperature and then exposed to a test flow. Using a layer of temperature sensitive crystal placed over the surface of this model or by other means, the time taken for the temperature at a relatively small number of selected points on the surface to reach a selected value is determined. The surface heat flux rate distribution is then found from these measured times using a simple inverse heat conduction method. The feasibility of this method has been evaluated by considering relatively low Reynolds number flow over a square cylinder and natural convective flow over a circular cylinder. Known local heat transfer coefficient distributions for these situation have been applied as boundary conditions in the numerical solution of the transient cooling of a the “experimental” models. These solutions are used to generate “measured” data i.e. to generate simulated experimental data. The inverse heat transfer method has then been used to predict the local heat transfer coefficient distribution over the surface and the predicted and input distributions have been compared. The effect of uncertainties in the experimental measurements on this comparison has then been evaluated using various assumed uncertainty values. The results of the study indicate that the proposed method of measuring local heat transfer coefficients is capable of giving results of good accuracy.
Heat Flux: A Design, Diagnostic and Control Parameter for Thermal Equipment
Authors: Martins N. , Afgan N. H. , Carvalho M. G. , Nogueira M.
Published: December 2021

Heat flux is a space and time variable reflecting the state of a thermal system. The evaluation of heat flux properties in thermal systems gives the possibility of making an assessment of their efficiency, safety and availability. In this respect, it was proved that heat flux is an important design, diagnostic and control parameter for many thermal systems.

This paper describes the evaluation of different aspects of heat flux properties including heat flux as a design parameter, heat flux as a diagnostic parameter and heat flux as a control parameter.

The heat flux is proved to reflect the changes in thermal equipment during operation. The malfunction of this equipment is closely related to the change of the heat flux distribution within the system. In this respect, it was demonstrated that the failure of boilers and furnace operation could be diagnosed by the change in the heat flux distribution on the respective heat transfer surfaces. The heat flux, as a diagnostic variable for the assessment of the operation of thermal systems, will open a challenging opportunity for the design of on-line knowledge-based systems. This can be used for the assessment of efficiency and safety of thermal systems.

A new method for heat flux measurement is introduced with reference to its use in boiler and glass furnaces. It shows the advantages of the new method when applied in high temperature and hostile environments.
Reduction of Fire Hazards Downwind of Wind-Driven Fires by Tree Barriers: Part IV — Numerical Simulation of Real-Scale Fires Located in Kobe City, Japan
Authors: Satoh K. , Yoshihara H. , Sagae K. , Naba H. , Araiba K. , Yang K. T.
Published: December 2021

Earlier laboratory studies were carried out to determine the effectiveness of implementing the use of tree barriers to protect open areas such as parks and schoolyards from large wind-driven urban fires. Numerical simulations based on a field fire model also produced promising results which corresponded well with the laboratory experimental observations and measurement data The confidence gained in these earlier studies has led to the present study to simulate the implementation of various tree-barrier configurations in an actual park in Kobe City, Japan under real-scale fire and prevailing wind conditions similar to those encountered in the 1995 Great Kobe Earthquake. Among the various barrier configurations studied, it has been demonstrated that the best configuration is the one using a dual barrier system to reduce the temperatures in the open park downwind from the barriers to safe levels.
Numerical Modeling of Turbulent Heat Transfer and Fluid Flow in a Tunnel Pasteurization Process
Authors: Zheng Y. H. , Amano R. S.
Published: December 2021

The purpose of this study is to model the heat transfer and fluid flow in a tunnel pasteurizer, which can be used to predict the operation status of the pasteurization process. This modeling is very useful when some changes must be made to the design, operation, or the types of products to be pasteurized. Moreover, the model can be used to provide valuable data for the optimization of the pasteurization design.

In the modeling two approaches have been adopted. One is the Lumped Parameter Method (LPM), which is used to model the whole pasteurization system, including pipes, zones and heat exchangers. The other one is the Computational Fluid Dynamics (CFD) technology for calculations of the heat transfer and fluid flow rates in the heat exchanger tank. A steady state model in a tunnel pasteurizer has been developed by using the LPM. The temperatures of the spray water and the products in the pasteurization process were calculated by employing this model. The comparisons showed reasonably good agreements between the predicted results and the experimental data. The pressure variations along the regenerative loops were also calculated. With the CFD technology, the numerical calculations of heat transfer and fluid flow have been performed on the temperature distribution in the cylindrical heat exchanger tank that provides a hot water through the top and a cold water through the bottom of tank. There are two outlets. In the heat exchanger tank, the tube arrays are set along the azimuth direction of the tank. This is a thermally stratified layered water tank that can control the four zones of the water temperatures.
Pool Boiling Heat Transfer From Plain and Microporous, Square Pin Finned Surfaces in Saturated FC-72
Authors: Rainey K. N. , You S. M.
Published: December 2021

The present research is an experimental study of “double enhancement” behavior in pool boiling from heater surfaces simulating microelectronic devices immersed in saturated FC-72 at atmospheric pressure. The term “double enhancement” refers to the combination of two different enhancement techniques: a large-scale area enhancement (square pin fin array) and a small-scale surface enhancement (microporous coating). Fin lengths were varied from 0 (flat surface) to 8 mm. Effects of this double enhancement technique on critical heat flux (CHF) and nucleate boiling heat transfer in the horizontal orientation (fins are vertical) are investigated. Results showed significant increases in nucleate boiling heat transfer coefficients with the application of the microporous coating to the heater surfaces. CHF was found to be relatively insensitive to surface microstructure for the finned surfaces except in the case of the surface with 8 mm long fins. The nucleate boiling and CHF behavior has been found to be the result of multiple, counteracting mechanisms: surface area enhancement, fin efficiency, surface microstructure (active nucleation site density), vapor bubble departure resistance, and re-wetting liquid flow resistance.
Investigation of the Real Process Data on Basis of Closed Mass- and Energy Balances in Nuclear Power Plants (NPPs)
Authors: Grauf E. , Jansky J. , Langenstein M.
Published: December 2021

This contribution presents an overall mathematical survey of the nuclear power plant (NPP) process in terms of functional redundancy in relation to performance measurements and reactor output calculations.

With the help of VALI software it has been possible to verify significant differences in the average coolant temperature (CT) values compared with the displayed values, in particular in respect of starting up the plant. Corrections in the operating mode, which were made on the basis of the validation data, have resulted in maximum output being achieved more quickly.

By tracking the trends of the component output data calculated from validated data, it has been possible to obtain direct indications of weaknesses in the process engineering. With the help of an examination of sensitivity, an incorrect measuring chain response can be identified. For this purpose, automatically generated report forms are produced and these are used to maintain the measuring chains.

The replacement of equipment calibration by functional redundancy in relation to the measured performance values results in potential savings in respect of maintenance activities such as recurrent tests (RT) and recurrent maintenance measures (RM) of approx. DM 1.1 million per LWR unit/year.
Safety Engineering for the Relativistic Heavy Ion Collider at the Brookhaven National Laboratory
Authors: Musolino Stephen V. , Kane Steven F. , Levesque Joseph W.
Published: December 2021

The Relativistic Heavy Ion Collider (RHIC) is a high energy particle accelerator built to study basic nuclear physics. It consists of two counter-rotating beams of fully stripped gold ions that are accelerated in two rings to an energy of 100 GeV/nucleon. The rings consist of a circular lattice of superconducting magnets, 3.8 km in circumference. The beams can be stored for a period of five to ten hours and brought into collision for experiments during that time. The first major physics objective when the facility goes into operation is to recreate a state of matter, the quark-gluon plasma, that has been predicted to have existed at a short time after the creation of the universe. There are only a few other high energy particle accelerators like RHIC in the world. Each one is unique in design and contains systems and hazards that are not commonly found in general industry. Therefore, the designers of the machine do not always have consensus design standards and regulatory guidance available to establish the engineering parameters for safety. Some of the areas where standards are not available relate to the cryogenic system, containment of large volumes of flammable gas in fragile vessels in the experimental apparatus and mitigation of a Design Basis Accident with a stored particle beam. The ASME Code requires Charpy testing of welds at cryogenic temperature, but testing at 4 K is nearly impossible to conduct. Engineered welds were used to provide an equivalent level of safety. A cryogenic system is a process system. The RHIC system was designed first by selecting a safe operating mode, then analyzing to ensure this mode was preserved. Cryogenic systems have unique processes, and the safe mode will surprise most process engineers. The experimentalists require detectors to be designed to meet the need of the physics objectives, but the application of standard construction techniques would make research mission impossible. Unique but equivalent safety engineering must be determined. The rules promulgated in the Code of Federal Regulations under the Atomic Energy Act do not cover prompt radiation from accelerators, nor are there any State regulations that govern the design and operation of a large superconducting collider. Special design criteria for prompt radiation were developed to provide guidance for the design of radiation shielding.
Stress Analysis of Stainless Steel Elbow and Tee Fittings Subjected to Internal Pressure and External Loads
Authors: Sawa Toshiyuki , Furuya Tetsuya , Murakami Tadahiro , Kagaya Yasuyuki
Published: December 2021

In this paper, mechanical behaviors of the Elbow and Tee fittings connected to pipes by screw threads under internal pressure, external tensile loads and bending moment are analyzed using the Finite Element Method (FEM). FEM code employed is MARC. The maximum Mises stress of the Elbow and Tee fittings are obtained when the wall thickness is changed while the internal working maximum pressure is held constant at 20bar. The elasto-plastic stress states of screw threads the fittings and the pipes are obtained under internal pressure and external loads. Under the assumptions that nodal points are released when the strain of the elements reaches the rupture strain of the fitting’s material, the load when the rupture occurs at the screw thread is analyzed. The safety factor for the wall thickness of the Elbow and Tee fittings used in the experiment is found to be about 5. The results indicate deduced that the dimensions of Elbow and Tee fittings can be reduced. The strength of the fittings under internal pressure and external loads is obtained. It is found that the stress concentrates at the first root of male thread and expected that a fracture initiates at the first root. The strain of the Elbow and Tee fittings subjected to internal pressure were measured by using strain gauges. The numerical results are in a fairly good agreement with the experimental results.
Short Carbon Fibers Composites With High Filler Contents Rheology and Mechanical Properties
Authors: Schmitt Y. , Paulick C. , Bour Y. , Royer F. X.
Published: December 2021

The control of the quality of mixture based on very short carbon fibers and epoxyde resins leads to suitable mixture for molding of complex geometries. A gain in fluidity is obtained if the suspensions are treated by ultrasounds and simultaneously stirred under vacuum. Addition in a very small ratio of microbubbles in the mixture allows to obtain a viscosity less than those of the matrix alone. For many polymer materials the gain of fluidity can be of 20 to 25% with size and concentration of the microspheres thoroughly chosen. A certain number of new resins is developped to elaborate composite materials with specific mechanical properties close to standard aluminium. Tensile test an ultimate stress are used to quantify the improvements of the mechanical properties. Fillers concentrations up to 30 % are obtained.
Dynamics of Drops and Bubbles in Newtonian and Viscoelastic Flows
Authors: Pillapakkam Shriram B.
Published: December 2021

A finite element code based on the level set method is developed for simulating the motion viscoelastic free-surfaces in two-dimensions. This method is a generalization of the one described in Osher and Sethian (1988) where the free-surface problems of inviscid and viscous fluids were simulated. The code is used to study deformation of drops in simple shear and Poisuelle flows over a wide range of dimensionless capillary (Ca) and Deborah numbers (De). Simulations show that there are limiting values of these two parameters below which the drops assume steady state shapes. For values greater than these limiting values, on the other hand, there is no steady state shape and the drop continued to deform. For a Newtonian bubble rising in a quiescent viscoelastic liquid we again find that there are limiting values of the parameters De and Ca, above which the bubble assumes a characteristic shape with a cusp-like trailing edge. The numerical results show that the viscoelastic stresses near the trailing edge are extensional and act in the direction normal to the drop surface. The front of the bubble however remains round as the local viscoelastic and viscous stresses act to round the bubble. These results are in good agreement with the experimental results.
Reduced Order Models of Viscous Flows in Turbomachinery Using Proper Orthogonal Decomposition
Authors: Epureanu Bogdan I. , Dowell Earl H. , Hall Kenneth C.
Published: December 2021

The proper orthogonal decomposition technique is applied in the frequency domain to obtain reduced order models (ROM) of the flow in a cascade of airfoils. The flow is described by a inviscid-viscous interaction model where the inviscid part is described by the full potential equation and the viscous part is described by an integral boundary layer model. The fully nonlinear steady flow is computed and the unsteady flow is linearized about the steady solution. A frequency domain model is constructed and validated showing to provide similar results when compared with previous computational and experimental data presented in the literature.

A cascade of airfoils forming a slightly modified Tenth Standard Configuration is numerically investigated. We show that the ROMs with only 10 to 40 degrees of freedom predict accurately the unsteady response of the full system with approximately 10,000 degrees of freedom for the subsonic case. We also show that the ROMs with 15 to 75 degrees of freedom predict accurately the unsteady response of the full system with approximately 17, 500 degrees of freedom for the transonic case. The ROMs are shown to be accurate both for a broad range of reduced frequencies and a full spectrum of interblade phase angles.
ParNAS3D: LES Spray Simulation Using an Efficient Parallel Multidimensional Upwind Algorithm
Authors: Caraeni Doru , Bergstrom Christer , Fuchs Laszlo
Published: December 2021

A parallel flow-solver, ParNASSD1, has been developed at LTH2 for simulations of compressible flows in aeronautical and complex industrial applications. The Large Eddy Simulation (LES) technique is used to simulate turbulent flows. The code employs an efficient algorithm, based on the Residual Distribution Scheme approach, well suited for parallelization. It has been implemented in the SPMD paradigm, and uses the PVM defacto standard for message passing.

The ParNAS3D solver has been coupled with an independent spray-module, for LES of spray in compressible flows. This was also done using the PVM message passing system.

The combined LES-spray code has been used to investigate the injection, mixing and evaporation processes of a fuel spray in a gas turbine engine. The code proved to have an excellent scalability, both when running with and without the spray module.

This is the first report on the implementation of the ParNAS3D parallel algorithm. We present also the numerical algorithm employed in our code.
Effect of Si-Al Alloy on Kinetics of Reaction-Bonded SiC Infiltration Process
Authors: Ilegbusi Olusegun J. , Yang Jijin
Published: December 2021

The kinetics of reaction-bonded SiC infiltration process utilizing Si-Al matrix has been investigated theoretically using a modified Washburn model. The effect of alloy composition and temperature on infiltration has been quantified. The resulting characteristics depend on alloy composition of the secondary metallic phase. Specifically, aluminum generally suppresses the infiltration rate. Increasing the temperature enhances both the infiltration capacity and reaction rate.
ADHEAR device in bone conduction audiometry
Authors: Pfiffner Flurin , Kegel Andrea , Probst Rudolf
Published: December 2021

ADHEAR is a bone conduction hearing aid that uses an adhesive skin adapter. In the current study, the use of ADHEAR as an audiometric bone stimulator was investigated in normal-hearing subjects by comparing it to the standard Radio-Ear B71. Bone conduction thresholds of 15 normal-hearing subjects (aged 21–36 years) were measured four times in a randomized order, twice with the B71 and twice with the ADHEAR. There were no significant differences in test-retest reliability between the two devices. Subjectively rated comfort was better for the ADHEAR. The development of a specific audiometric adhesive bone stimulator may be warranted.
Temperature-adaptive radiative coating for all-season household thermal regulation
Authors: Tang Kechao , Dong Kaichen , Li Jiachen , Gordon Madeleine P. , Reichertz Finnegan G. , Kim Hyungjin , Rho Yoonsoo , Wang Qingjun , Lin Chang-Yu , Grigoropoulos Costas P. , Javey Ali , Urban Jeffrey J. , Yao Jie , Levinson Ronnen , Wu Junqiao
Published: December 2021

A passive turnoff

Passive radiative cooling technology uses the infrared atmospheric window to allow outer space to be a cold sink for heat. However, this effect is one that is only helpful for energy savings in the warmer months. Wang
et al
. and Tang
et al
. used the metal-insulator transition in tungsten-doped vanadium dioxide to create window glass and a rooftop coating that circumvents this problem by turning off the radiative cooling at lower temperatures. Because the transition is simply temperature dependent, this effect also happens passively. Model simulations suggest that these materials would lead to energy savings year-round across most of the climate zones in the United States. —BG
Physiological costs of undocumented human migration across the southern United States border
Authors: Campbell-Staton Shane C. , Walker Reena H. , Rogers Savannah A. , De León Jason , Landecker Hannah , Porter Warren , Mathewson Paul D. , Long Ryan A.
Published: December 2021

Dangerous terrain

As climate change leads to regions of the world becoming increasingly uninhabitable, unregulated human migration is likely to increase. Migrants often traverse dangerous terrain, and the environmental conditions they encounter when exposed can be deadly. Campbell-Staton
et al
. used an approach commonly used to predict spatially explicit regions of physiological challenge in animal species to create a hazard landscape for the border crossing between the United States and Mexico. Their predictions of high risk, particularly due to dehydration, coincided with regions of high migrant mortality. Such detailed predictions may help to prevent these tragedies. —SNV
Radical quantum oscillations
Authors: Hore P. J.
Published: December 2021

Laser spectroscopy reveals spin quantum beats in electron transfer reactions
Key Antarctic ice shelf is within years of failure
Authors: Voosen Paul
Published: December 2021

Breakup of shelf holding back Thwaites Glacier will ramp up sea level rise
Requirements and Study Designs for U.S. Regulatory Approval of Influenza Home Tests
Authors: Yang Tony , Kessler Larry G. , Thompson Matthew J. , Lutz Barry R.
Published: December 2021

Home testing for infectious disease has come to the forefront during the COVID-19 pandemic. There is now considerable commercial interest in developing complete home tests for a variety of viral and bacterial pathogens.
Complete Genome Sequences of Two Novel Species from the
Pseudonocardiaceae
Family Isolated from the Persian Gulf
Authors: Safaei Nasim , Bunk Boyke , Spröer Cathrin , Wink Joachim , Mast Yvonne
Published: December 2021

Amycolatopsis
sp. strain DSM 110486 and
Pseudonocardia
sp. strain DSM 110487 are two novel actinomycete species that were isolated from Hengam Island beach sand from the Persian Gulf. Here, we present the complete genome sequences of DSM 110486 and DSM 110487, with sizes of 10.98 Mbp and 10.33 Mbp, respectively.
Supplemental Material: Ordovician–Silurian back-arc silicic magmatism in the southernmost Appalachians
Authors: Barineau Clinton I. , al. et
Published: December 2021

Sample Preparation and Geochemical Analysis Methodology; Table S1: Major oxide percentages for metaigneous rocks of the Wedowee-Emuckfaw-Dahlonega basin; Table S2: Measured isotope ratios and normalized U-Pb ages calculated without 204Pb Correction; Table S3: Lu-Hf isotope analyses; Table S4: Latitude-longitude (WGS84), geologic unit, and age information for samples analyzed as part of this project.
Search for Peptides Specifically Binding with the B7-2 Costimulatory Molecule
Authors: Kolosova E. A. , Viktorina O. E. , Chapoval A. I. , Shcherbakov D. N.
Published: December 2021

Abstract—

The interaction of B7-1/B7-2 ligands with CD28/CTLA-4 receptors plays a key role in the regulation of the immune response. The aim of this study was to find and study peptides that interact with the human B7-2 molecule. In the course of the work, three rounds of affinity selection were carried out and individual phage clones were selected, which include peptides with varying degrees of interaction with the coregulatory target B7-2. As a result of DNA sequencing of selected phages, nucleotide sequences encoding peptides that specifically bind to B7-2 were obtained. The identified peptides can be used as a basis for the development of immunotherapeutic drugs for regulating the immune response in the treatment of oncological diseases.
Ideal cardiovascular health duration and risk of chronic kidney disease and cardiovascular disease
Authors: Cho So Mi Jemma , Jeon Justin Y , Yoo Tae-Hyun , Lee Hae-Young , Lee Yong-ho , Kim Hyeon Chang
Published: December 2021

Objective

Increasing number of clinical guidelines are adopting comprehensive cardiovascular risk assessment tools for treatment decision and disease management. Yet, little is known regarding cardiovascular risks associated with the length of favourable cardiometabolic profile. In this context, we examined whether the duration of strictly ideal cardiovascular health (CVH), based on body mass index, blood pressure, fasting glucose, total cholesterol, cigarette smoking, alcohol drinking and physical activity, in middle age is associated with risk of developing chronic kidney disease (CKD) and cardiovascular disease (CVD) in mid-to-late life.

Methods

From the Korean Genome and Epidemiology Study Ansung-Ansan cohort, we included 8020 participants (median age 50.0 years, 47.9% male), of whom, 7854 without CKD and 7796 without CVD at baseline. Cox proportional hazards models were employed to assess CKD and CVD risks, adjusting for age, sex, education level, examination sites and renal markers.

Results

Over a median follow-up of 15.0 years, 1401 cases of CKD and 493 cases of CVD were newly developed. Compared with participants with <5 years of ideal CVH duration, HR (95% CI) of those who maintained for 5–<10 years or ≥10 years had negatively graded risks for CKD (5–<10 years, 0.63 (0.39 to 0.93); ≥10 years, 0.33 (0.15 to 0.74)) and CVD (5–<10 years, 0.83 (0.54 to 1.27); ≥10 years, 0.22 (0.08 to 0.60)). In parallel, participants with delayed decline to suboptimal level had lower disease risks compared with counterparts with consistently suboptimal CVH.

Conclusion

Our findings confer that maintaining favourable health behaviours and clinical risk factor levels in midlife will improve later-life cardiovascular outcomes.
Monitoring the water balance of seepage lakes to track regional responses to an evolving climate
Authors: Watras Carl J. , Michler James R. , Rubsam Jeff L.
Published: December 2021

Understanding the causes of large fluctuations in lake water levels is important for adaptive resource management. The relatively simple water budgets of small seepage lakes make them potentially useful model systems, provided that key water balance components can be well constrained. Here, spatial variability in measured rates of evaporation (E) and precipitation (P) at the whole lake scale was investigated, and the effect on daily and seasonal water balance estimates was quantified. To estimate spatial variability, triplicate sensor platforms were deployed on and near an 18 ha seepage lake. Lake stage (S) was monitored at a single node in the lake. The water balance was closed by estimating net groundwater seepage (Gnet) analytically as Gnet = ΔS – (P – E). Instrumentation on a second seepage lake was maintained by citizen scientists to assess the potential for more widespread sensor deployments. Data were collected at 30-minute time steps for six months. The results indicate that low-cost sensor networks with single nodes to measure E, P, and ΔS provide well-constrained water budgets at daily and seasonal time scales.
Whole-genome comparative analysis reveals genetic mechanisms of disease resistance and heat tolerance of tropicalBos indicuscattle breeds
Authors: Vijayakumar Periyasamy , Singaravadivelan Arunasalam , Mishra Anamika , Jagadeesan Krishnan , Bakyaraj Sanniyasi , Suresh Ramalingam , Sivakumar Thiagarajan
Published: December 2021

Bos indicus cattle breeds have been naturally selected for thousands of years for disease resistance and thermo-tolerance. However, the genetic mechanisms underlying these specific inherited characteristics must be elucidated. Hence, in this study, a whole-genome comparative analysis of the Bos indicus cattle breeds Kangayam, Tharparkar, Sahiwal, Red Sindhi, and Hariana of the Indian subcontinent was conducted. Genetic variant identification analysis revealed 155 851 012 SNPs and 10 062 805 InDels in the mapped reads across all Bos indicus cattle breeds. The functional annotation of 17 252 genes that comprised both SNPs and InDels, with high functional impact on proteins, was carried out. The functional annotation results revealed the pathways involved in the innate immune response, including toll-like receptors, retinoic acid-inducible gene I-like receptors, NOD-like receptors, Jak-STAT signaling pathways, and non-synonymous variants in the candidate immune genes. We also identified several pathways involved in the heat shock response, hair and skin properties, oxidative stress response, osmotic stress response, thermal sweating, feed intake, metabolism, and non-synonymous variants in the candidate thermo-tolerant genes. These pathways and genes directly or indirectly contribute to the disease resistance and thermo-tolerance adaptations of Bos indicus cattle breeds.
Frequent numerical and structural chromosome changes in early generations of synthetic hexaploid wheat
Authors: Zhang Siyu , Du Pei , Lu Xueying , Fang Jiaxin , Wang Jiaqi , Chen Xuejun , Chen Jianyong , Wu Hao , Yang Yang , Tsujimoto Hisashi , Chu Chenggen , Qi Zengjun
Published: December 2021

Modern hexaploid wheat (Triticum aestivum L.; AABBDD) has evolved from a hybrid of tetraploid wheat (closely related to Triticum turgidum L. ssp. durum (Desf.) Husn., AABB) and goatgrass (Aegilops tauschii Coss., DD). Variations in chromosome structure and ploidy have played important roles in wheat evolution. How these variations occur and their role in expanding the genetic diversity of modern wheat remain largely unknown. Synthetic hexaploid wheat (SHW) can be used to investigate chromosome variations that occur during the early generations of existence. SHW lines derived by crossing durum wheat ‘Langdon’ with 12 Ae. tauschii accessions were analyzed using oligonucleotide probe multiplex fluorescence in situ hybridization (FISH) of metaphase chromosomes and SNP markers. Cluster analysis based on SNP markers categorizes them into three groups. Among 702 plants from the S8 and S9 generations, 415 (59.12%) carried chromosome variations involving all 21 chromosomes, but with different frequencies for each chromosome and sub-genome. Total chromosome variation frequencies varied between lines, but there was no significant difference among the three groups. The non-random chromosome variations in the SHW lines detected in this study may indicate that similar variations occurred in the early stages of wheat polyploidization and played important roles in wheat evolution.
An alternative scheme for effective range corrections in pionless EFT
Authors: Ebert M. , Hammer H.-W. , Rusetsky A.
Published: December 2021

We discuss an alternative scheme for including effective range corrections in pionless effective field theory. The standard approach treats range terms as perturbative insertions in the T-matrix. In a finite volume this scheme can lead to singular behavior close to the unperturbed energies. We consider an alternative scheme that resums the effective range but expands the spurious pole of the T-matrix created by this resummation. We test this alternative expansion for several model potentials and observe good convergence.
LSBR Speech Steganalysis Based on Percent of Equal Adjacent Samples
Authors: Yazdanpanah Saeid , Kheyrandish Mohammad , Mosleh Mohammad
Published: December 2021

Wide utilization of audio files has attracted the attention of cyber-criminals to employ this media as a cover for their concealed communications. As a countermeasure and to protect cyberspace, several techniques have been introduced for steganalysis of various audio formats, such as MP3, VoIP, etc. The combination of machine learning and signal processing techniques has helped steganalyzers to obtain higher accuracies. However, as the statistical characteristics of a normal audio file differ from the speech ones, the current methods cannot discriminate clean and stego speech instances efficiently. Another problem is the high numbers of extracted features and analysis dimensions that drastically increase the implementation cost. To tackle these, this paper proposes the Percent of Equal Adjacent Samples (PEAS) feature for single-dimension least-significant-bit replacement (LSBR) speech steganalysis. The model first classifies the samples into speech and silence groups according to a threshold which has been determined through extensive experiments. It then uses an MLP classifier to detect stego instances and determine the embedding ratio. PEAS steganalysis detects 99.8% of stego instances in the lowest analyzed embedding ratio — 12.5% — and its sensitivity increases to 100% for the ratios of 37.5% and above.
Nonlocal gravity cosmology: An overview
Authors: Capozziello Salvatore , Bajardi Francesco
Published: December 2021

We discuss some main aspects of theories of gravity containing nonlocal terms in view of cosmological applications. In particular, we consider various extensions of general relativity based on geometrical invariants as [Formula: see text], [Formula: see text] and [Formula: see text] gravity where [Formula: see text] is the Ricci curvature scalar, [Formula: see text] is the Gauss–Bonnet topological invariant, [Formula: see text] the torsion scalar and the operator [Formula: see text] gives rise to nonlocality. After selecting their functional form by using Noether symmetries, we find out exact solutions in a cosmological background. It is possible to reduce the dynamics of selected models and to find analytic solutions for the equations of motion. As a general feature of the approach, it is possible to address the accelerated expansion of the Hubble flow at various epochs, in particular the dark energy issues, by taking into account nonlocality corrections to the gravitational Lagrangian. On the other hand, it is possible to search for gravitational nonlocal effects also at astrophysical scales. In this perspective, we search for symmetries of [Formula: see text] gravity also in a spherically symmetric background and constrain the free parameters, Specifically, by taking into account the S2 star orbiting around the Galactic Center SgrA[Formula: see text], it is possible to study how nonlocality affects stellar orbits around such a massive self-gravitating object.
Problem of energy scale in rigid triaxial rotor model
Authors: Gupta J. B. , Katoch Vikas
Published: December 2021

The problem of mismatching of the level energies, in the ground band and the [Formula: see text]-band of triaxially deformed atomic nuclei, as predicted in the rigid triaxial rotor (RTR) approximation of Davydov and Filippov (DF) model, with experiment, is well known. Here, we illustrate the solutions suggested in the literature, and the deviations observed in the converted energy values, from the experiment. We analyze the source of problem of this mismatch with experiment. This enables a physical picture of the DF (or RTR) model spectra. Our analysis will help in understanding the merits and the limitation of the RTR model in this respect.
Bubble structure in superheavy nuclei around neutron and proton shell closure
Authors: Yadav Akhilesh , Shukla A. , Åberg Sven
Published: December 2021

We have performed a systematic study for the nuclear structure of superheavy nuclei with a special emphasis on the nuclei with possible central depletion of proton and neutron density in the mass region [Formula: see text] using the Relativistic Hartree–Bogoliubov (RHB) framework. It has been observed that in the case of neutron density distribution, the occurrence of central depletion is related to the occupancy of 4s orbital and it is found to decrease with increasing occupancy of the 4s orbital. On the other hand, in the case of proton density distribution, the central density depletion is mainly due to the lowering of weakly bound p-orbital states close to the continuum as it is energetically favored to lower the Coulomb repulsion in the case of superheavy nuclei. Also, occupation probability of the lower angular momentum states (p-orbitals) lying near the Fermi level is strongly suppressed due to the weak centrifugal barrier and strong Coulomb repulsion in comparison to large angular momentum states (contributing to surface region mainly), resulting in central density depletion. Among the considered cases in the present work, the maximum depletion is observed for [Formula: see text] and for [Formula: see text]Og under spherically symmetric and axially deformed cases, respectively.