bluuebunny/crossref_metadata_2025 huggingface dataset:
Economics of oilseed crushing: assessing the impact of solvent-free processing on added value
Authors: Carré Patrick
Published: November 2024

While it is clear that solvent extraction (SE) dominates the vegetable oil production sector because of the higher yields it allows, it is more difficult to estimate the difference in added value (AV) between this production method and extraction by mechanical means alone (ME). The aim of this article is to propose an objective method for assessing this differential by addressing the question of assessing the material balances associated with each process and the issue of the value of expeller cakes in different economic contexts, an assessment made necessary by the absence of regular public quotations for these feedstuffs. Material balances are determined by the oil content in the seeds and the oil residues left in SE meals and ME cakes. Based on 100 kg of seeds, oil production was estimated at 43.7 and 44.9 kg using the SE process compared with 39.3 and 38.8 kg using the ME process for rapeseed and sunflower respectively. To assess the value of expeller cakes, we used a basket of feedstuffs with known quotations and nutritional value to determine an equation for price prediction within 35 market conjunctures between June 2008 and May 2024. These predictions were used to establish a linear correlation between hexane meal prices and predicted expellers prices allowing a calculation of the added value in 574 market situations from 2010 to 2024. A linear regression shows that AV of ME is equal to 0.71 AV of SE + 6.8 €/t for rapeseed and 0.63 AV of SE + 2.1 €/t for sunflower.
Comparative assessment of yield, oil content and fatty acid composition of spiny and non-spiny safflowers
Authors: Sajid Muhammad , Munir Hassan , Rasul Fahd , Hayat Muhammad Abu Bakar
Published: November 2024

Safflower (Carthamus tinctorius L.) is one of the edible oilseeds crops which is neglected due to its spiny nature that poses difficulties in field operations; however, this problem can be sorted out by introducing non-spiny safflower cultivars. Hence, a 2-year study (2020–2021 and 2021–2022) was planned to assess the production potential of spiny (5 accessions) and non-spiny (5 accessions) safflower germplasm and an experiment was laid out using randomized completed block design (RCBD) under semiarid conditions of Faisalabad (Pakistan). Agronomic and oil traits were targeted during study. In 2021, non-spiny safflower accession PI-198990 gave the highest seed yield and oil percentage as compared to spiny safflower. However, the highest linoleic concentration was noted in spiny PI-199829 accession whereas the greatest oleic acid percentage was determined in non-spiny PI-235660 accession. Principal component analysis unveiled two components accounting for 39.5% and 25.7% of total variation. Biplot graph indicated that seed oil content, seed yield and 1000-seed weight had the highest correlation in the 2nd group while in the 3rd group plant height, days to maturity and oleic acid were correlated. These targeted characters can be considered as suitable index for selection of safflower elite accessions for semi-arid conditions. In general, non-spiny safflower accession responded 19%, 4.3%,10.7%, 21.6%, 6.2% and 77.9% greater in plant height, number of branches, number of heads (capitula), 1000-seed weight, seed yield and oleic acid respectively. From the data of this 2-year studies, we concluded that spiny safflower accessions exhibited 1.2% and 16.3% more oil and linoleic acid content respectively.
Evaluating the impact of official development assistance on ecological environments in agricultural and renewable energy sectors
Authors: Li Rongrong , Guo Jiaqi , Wang Qiang
Published: November 2024

This study examines the complex interactions between official development assistance (ODA) and the ecological environment of recipient countries, mainly focusing on agricultural economic development and renewable energy. Using dynamic threshold models and robust statistical methods, the analysis uncovers the nuanced effects of ODA across various dimensions. Findings suggest that ODA has different impacts on the ecology of African countries depending on their agricultural dependence and renewable energy development levels. The study highlights the importance of targeted aid and advocates for the integration of ODA with environmentally sustainable development goals. Furthermore, the research underscores the potential for environmental improvement in countries with significant agricultural reliance. It emphasizes the critical role of renewable energy in mitigating ecological pressures and adapting to climate change. This study contributes to the assessment of sustainable development performance after the expiration of the United Nations Sustainable Development Goals in 2030.
Response of a squid of finite junction width to an external magnetic field
Authors: Shmidt V. V. , Stelmakh V. G.
Published: November 2024

A theoretical analysis is made of how a hollow superconducting cylinder shorted with a finite-width Josephson junction responds to an external magnetic field. The total magnetic flux Φ in the cylinder is studied as a function of the external magnetic flux Φx introduced into the cylinder. A qualitative method is proposed for analysis of the dependence of Φ on Φx The stability of states of a cylinder with flux Φ is studied and the results of a numerical calculation of the stability are presented.
Electrical conductivity of point microbridges and phonon and impurity spectroscopy in normal metals
Authors: Kulik I. O. , Omel’yanchuk A. N. , Shekhter R. I.
Published: November 2024

A theory of the nonlinear effects in the electrical conductivity of metallic microbridges is constructed which is based on a model consisting of a hole of radius a in an impermeable partition separating two metallic half-spaces. The electron distribution function, which is a function of the coordinates and which is sharply anisotropic in momentum space, and the electric field distribution in the vicinity of the constriction are found in the limit 1 ⪢ a (where 1 is the electron mean free path). The current–voltage characteristic of the bridge contains nonlinearities induced by inelastic relaxation of electrons on phonons and also on impurities with internal degrees of freedom. The second derivative of the current with respect to voltage is proportional to the constriction spectral function G(ω), which differs from the electron–phonon coupling function normally employed g(ω) by the presence of an additional structure factor K(v,v′) allowing for the geometry of the constriction. At small frequenceis (ω ⪡ ωD) the function G(ω) is proportional to ω4; at frequencies ω ∼ ωD the constriction spectral function G(ω) reflects the singularities of the phonon density of states (including the van Hove singularities). In the case of inelastic scattering of electrons on impurities localized near the hole, the function G(ω) contains peaks corresponding to the discrete impurity excitation levels.
Magnetism of conduction electrons near points of variation in the topology of isoenergetic surfaces
Authors: Nedorezov S. S.
Published: November 2024

The magnetic susceptibility χ of conduction electrons is analyzed under conditions of nearness of the chemical potential ζ to the value of the energy ϵk at which the topology of isoenergetic surfaces changes, i.e., for | ζ−ϵk| ≪ ζ. It is shown that the susceptibility depends non-monotonically on the temperature T which has an extremum at the point T1. In weak magnetic fields H the displacement ΔT of the temperature T1 and the change Δχ in the extremum χ are quadratic in H. Formulas are obtained for ΔT and Δχ, which afford the possibility of determining the electron energy spectrum near ϵk from the results of measuring these quantities.
Temperature dependence of the specific heat of V3Si
Authors: Pan V. M. , Prokhorov V. G. , Shevchenko A. D. , Dovgopol V. P.
Published: November 2024

The temperature dependence of the specific heat is analyzed for a single crystal of V3Si with a stoichiometric composition and with an electrical-resistivity ratio α = ρ300/ρ18 = 25. It is shown that the trend of the specific heat in the high-temperature range can be explained only with the anharmonicity of lattice vibrations taken into account.
Optical absorption of erbium in paramagnetic and ferromagnetic states
Authors: Knyazev Yu. V. , Noskov M. N.
Published: November 2024

The optical constants of polycrystalline erbium were measured at temperatures 56−293 °K in the spectral region 0.06−4.4 eV. The wide maximum observed at 1−3 eV in the plot of the optical conductivity against frequency is explained by quantum band-to-band transitions. When the specimens are cooled below the Néel temperature, the decrease in the relaxation frequency of optically-active electrons with the temperature slows down and a new absorption peak, due to s-f exchange interaction, is formed at 0.28 eV.
Singularities in temperature and time dependence of charge motion in solid helium
Authors: Efimov V. B. , Mezhov-Deglin L. P.
Published: November 2024

The results of measurements of the dynamic and static characteristics of a diode in solid helium are presented. With the voltage switched on in a stepwise fashion the velocity of charge motion in the helium can be assessed from the position of the current maxima in the time diagrams. A composition plot of the activation energy versus the specific volume is presented for diffusion of various microparticles in He3. The I(T) curves of the current as a function of the temperature in He4 have been found to have maxima at low voltages.
Spin-spin interactions of Cu2+ ions in zinc fluosilicate
Authors: Kozhukhar’ A. Yu. , Tsintsadze G. A.
Published: November 2024

Spin–spin interactions of Cu2+−Cu2+ impurity pairs were studied by the EPR technique. The angular dependence of the position of the EPR spectral lines of Cu2+−Cu2+ pairs in a magnetic field served as the basis for determining the form of the spin Hamiltonian Hij which describes the interactions of exchange–coupled pairs as well as for finding the parameters of the magnetic dipole–dipole and isotropic exchange interactions of nearest–neighbor Cu2+ions in the crystal.
Self-diffusion and nuclear magnetic relaxation in liquid methane-argon mixtures
Authors: Mikhailenko S. A. , Yakuba V. V. , Butko A. E.
Published: November 2024

The spin echo method was used to measure the self-diffusion coefficients of CH4 and the spin–lattice relaxation times T1 in liquid CH4−Ar mixtures over the entire range of concentrations and at temperatures 100 ≤ T ≤ 150°K along the liquid-vapor curve. The experimental relations D(x, T) are shown to be in qualitative agreement with conclusions based on the assumption of individual (“single-particle”) and collective hydrodynamic contributions to the diffusion processes. The maxima on the T1(T) curves were found to shift to lower temperatures with an increase in concentration, this being attributed to an increase in the spin-rotational contribution to the relaxation rate. Separating this contribution, we determined the x, T dependences of the orientational and angular-velocity correlation times, τθ and τJ, and analyzed the changes in the character of the rotational motion of the CH4 particles with a change in the composition of the mixture.
Ultrasound velocity in liquid neon
Authors: Pashkov V. V. , Konovodchenko E. V.
Published: November 2024

The ultrasound velocity has been measured in liquid neon by means of a pulse technique at 5 MHz at temperatures between 26.95°K and 38.88°K and pressures as high as 150 atm. The generalized law of corresponding states (LCS) is used to analyze the data. It is shown that in neon deviations from the law of corresponding states are due primarily to quantum effects, and a consistent method for including such effects is suggested.
Theory of electronic transport of sound packets in metals in parallel magnetic field
Authors: Bogachek E. N. , Rozhavskii A. S. , Shekhter R. I.
Published: November 2024

A theory is constructed for the propagation of sound pulses in metals in a magnetic field parallel to the wave front. Under the conditions of strong spatial dispersion kl≫ kR≫ 1 (k is the sound wave vector, l is the electron mean free path, and R is the cyclotron radius), because of deformation interaction with electrons in the metal a sound wave in pure samples gives rise to a system of spikes at distances which are multiples of 2R and move synchronously with the sound wave at the speed of sound. It is shown that the spike amplitudes are proportional to the squared local values of the deformation interaction potential Λ(p) and that their attenuation is determined by the averaged value of the potential. Attention is drawn to the possibility of establishing the form of Λ(p) by comparing theoretical and experimental results. The salient features of the formation of spikes are analyzed for an arbitrary electron dispersion relation.
On the theory of double Ising chains. Model in a zero external field
Authors: Yurishchev M. A.
Published: November 2024

The free energy and initial magnetic susceptibility of a double Ising chain are calculated with account of diagonal interactions in a cell, four-particle interactions, and also under the assumption of distinct, generally speaking, g-factors of particles belonging to the different one-dimensional chains from which the double Ising chain is constructed. The temperature behavior of the specific heat and the initial magnetic susceptibility is studied by using an electronic computer. Simple asymptotic dependences for the specific heat and the susceptibility are obtained in the high temperature limit.
Wave processes in parallel channels with different degrees of damping of the normal component of superfluid helium
Authors: Kekutiya Sh. E. , Karchava T. A. , Sanikidze D. G.
Published: November 2024

The propagation of waves is considered, in a waveguide with a superleak, completely filled with superfluid He-II under conditions of partial damping of the normal component of the liquid. The velocities of propagation and also the coefficients of absorption of the combined first and fourth sounds and a modified second sound are calculated, and their dependence on the parameter δ = (L−d)/λv is explained (L is the height of the superleak, d is the thickness of the layer of porous material in the superleak and λv is the depth of penetration of the viscous wave). Such a waveguide can serve as a model for the propagation of waves in a filter having channels of different diameters.
Rotational molecular motion in NH3 and ND3 crystals
Authors: Brodyanskii A. P. , Freiman Yu. A.
Published: November 2024

A model intermolecular interaction potential is suggested and used to calculate the temperature dependence of librational energies, order parameters, free energy, heat capacity, and Grüneisen constant of the rotational subsystems of solid ammonia and deutero-ammonia. The calculations are performed in the anharmonic approximation, using the Bogolyubov variational method. The nature of the anomalous isotope effect is explained.
A new metastable superconducting modification of bismuth attainable in ultrathin films
Authors: Lazarev B. G. , Semenenko E. E. , Tutov V. I. , Chupikov A. A.
Published: November 2024

The superconductor properties of ultrathin (18−70 Å) bismuth films were studied, these films having been produced by condensation of metal vapor on a surface cooled down to 2°K. It has been established that the superconducting transition temperature becomes higher after annealing of such films and that the magnitude of this upward shift is a function of the film thickness. The maximum shift is Δ Tc = 0.9°K for a film 18 Å thick, the shift is smaller for films thicker than that, until there is no shift for films thicker than 40 Å. The highest superconducting transition temperature after annealing of all specimens of all thicknesses did not exceed 3.6°K. These data as well as the previously known anomalous dependence of dHc/dT, electrical resistivity, and coordination structure of freshly condensed thin bismuth films on their thickness suggest that such films thinner than 40 Å form as a different modification than that of thicker films. The hypothesis is proposed here that this modification is a distorted variant of the high-pressure Bi-II phase.
Coexistence of superconductivity and ferromagnetism in layered systems
Authors: Pashitskilĭ É. A. , Shpigel’ A. S.
Published: November 2024

It is shown for layered systems that when the electronic concentration varies monotonically from layer to layer the homogeneous superconducting electron pairing of adjacent layers with antiparallel spins is accompanied by a spontaneous ferromagnetic ordering (the SF-phase), while in the case of nonequivalent alternating layers a paramagnetic superconducting state (the SP-phase) is generated for certain magnetic fields H and chemical potential differences δμ between adjacent layers. The paramagnetic limit grows with increasing δμ, and the transition from the normal to the superconducting (SF or SP) state is a first order phase transition both in the field H and in δμ.
Spin configuration of biaxial antiferromagnets in a longitudinal magnetic field
Authors: Ostrovskii V. S.
Published: November 2024

We investigate the influence of a single-ion anisotropy on the spin configuration (the spin directions and the average magnitudes of the spin projections) of biaxial antiferromagnets in a magnetic field applied along the “easy” axis of the crystal. We study the configuration of the antiferromagnetic and spin-flop phases of a highly anisotropic antiferromagnet at T = O, and of a weakly anisotropic antiferromagnet near TN. In the latter case we calculate the H-T phase diagram. It is shown that the presence of a single-ion anisotropy leads to a number of specific properties of these crystals. For example, the order of the phase transition can change which is most evident at low temperatures. In the limit T = 0 we obtain a closed system of equations which describe the behavior of crystals whose magnetism is due to ions with spin S = 1, in an arbitrary magnetic field.
Instability of the electron Fermi liquid in a magnetic field
Authors: Kaner É. A. , Chebotarev L. V. , Uvimana Ézhen
Published: November 2024

The possibility of instability and phase transition in a metal is investigated in a model with the lattice replaced by a homogeneous charge-compensating background. It is shown that the state of such a system can become unstable near a singularity of the density of states on the Fermi surface under the condition that the average value of the Landau function, computed on the extremal cross section of the Fermi surface, is negative. Unlike the usual situation, with decreasing temperature the system goes from the liquid to the gaseous phase.
Self-focusing of second sound in superfluid helium
Authors: Nemirovskii S. K.
Published: November 2024

The Hamiltonian formalism is used to study the behavior of wide wave packets of second sound near the temperature at which the nonlinear correction to the sound velocity vanishes. The interaction between first and second sounds is shown to result in self-focusing and self-channeling of wave packets. The critical intensities for observing this effect and the lateral dimension of the waveguide channel are calculated.
Surface electrons in helium over macroscopic periodic structures
Authors: Ginzburg VI. L. , Monarkha Yu. P.
Published: November 2024

It is shown that there is a new possibility of realizing a band-type spectrum for electrons in superlattices with a macroscopic period by using surface electrons in liquid helium. A substrate with a periodic surface profile (of the diffraction grating type) is proposed as the superlattice. The parameters of the electron spectrum are calculated and an analysis is made of the possibility of observing effects which are nonlinear (in the electric field).
Electrical properties of bismuth-antimony thin films. III. Quantum size effect
Authors: Komnik Yu. F. , Nikitin Yu. V. , Bukhshtab E. I.
Published: November 2024

We investigated the distinctive aspects of the quantum size effect in thin films of Bi1−xSbx alloys. The variations in the resistance ratio R4.2/R300 were studied in specimens of two types: specimens of varying thickness but fixed composition and varying composition but fixed thickness. The effective quasimomentum pzmax, which determines the period of the quantum size oscillations, is shown to be almost insensitive to variations in the thickness. Data for two forms in which the quantum size effect manifested itself in thin films of Bi1−xSbx alloys are used to plot pzmax versus the alloy composition (the direction of the smaller dimension z coincides with the trigonal axis C3).
Effect of the surface and bulk anisotropy on the ground state of thin ferromagnetic layers
Authors: Sementsov D. I. , Syabro V. A.
Published: November 2024

The ground state is studied of a thin ferromagnetic layer with “easy axis” type anisotropy β0 ≥ 4π and arbitrary bulk anisotropy constant varying in the range − ∞ ≤ β ≤ 4π. An exact analytical solution of the problem is presented. The equations obtained allow the calculation of the magnetization direction at the center of the layer as a function of the parameters of the system as well as the equilibrium distribution of magnetization in the whole system in both the rigid surface spin pinning and the finite surface anisotropy cases. It is shown that there exist two phase transition points from a nonuniform to a uniform state.
Phase transitions in CsDy(MoO4)2 doped with trivalent ion impurities
Authors: El’chaninova S. D. , Zvyagin A. I.
Published: November 2024

The effect of impurities on the structural phase transition temperature in CsDy(MoO4)2 is investigated. It is shown that the phase transition temperature decreases sharply with the reduction of Dy3+ ion concentration. In doped crystals, a new phase transition is found in the temperature range 20–30 °K.
Anomalies in the low-temperature kinetic properties of Ni–Mn alloys
Authors: Beilin V. M. , Rogel’berg I. L. , Cherenkov V. A.
Published: November 2024

The resistivity ρ, thermoelectric power S, and magnetization M of Ni-Mn alloys (6.6% ≤ cMn ≤ 9.8%) have been investigated in the temperature interval 4.2−77.3 °K. Two sharp maxima were observed on the temperature dependences of dρ /dT, S, and M in the Ni + 8.3% Mn alloy between 20 and 50°K. They may be attributed to two magnetic states of the manganese atoms having parallel and antiparallel (to the mean magnetization) spin orientations. It is suggested that the “antiparallel” state corresponding to the presence of Mn clusters is formed at lower temperatures than the “parallel” state.
NMR study of the normal spinel FeCr2S4 at low temperatures
Authors: Kovtun N. M. , Prokopenko V. K. , Prokhorenko Yu. I. , Shemyakov A. A.
Published: November 2024

The NMR spectra of the normal ferrimagnetic spinel FeCr2S4 have been studied in the temperature range 2–77°K. In the vicinity of 10°K a transition is observed from the dynamical Jahn-Teller distortions of the symmetry of the surroundings of the tetrahedral Fe2+ ions, occurring at high temperatures, to static distortions.
Frequency-dependent breakdown of backward volume spin-wave soliton formation
Authors: Iwata Tokiya , Nezu Shoki , Sekiguchi Koji
Published: November 2024

This study investigates the propagation characteristics of spin waves in an yttrium iron garnet waveguide using a vector network analyzer and a real-time oscilloscope. We confirm the propagation of backward volume magnetostatic spin waves in the linear regime. Solitary spin-wave formation was observed, and the transition from linear to nonlinear response was verified by establishing a threshold power. In the nonlinear regime, collision experiments between two spin waves were conducted, revealing a dependence of attenuation on the input carrier frequency. A comparison with the transmission loss curve confirms the correlation between attenuation and the position of “frequency regions with strong dispersion.” Notably, only within a specific frequency range among these regions do the colliding spin waves maintain their shapes and momenta, passing through each other without dissipation. This remarkable phenomenon is crucial for dissipation-free information transfer. Our findings offer valuable insights into spin-wave behavior, particularly for developing spin-wave-based logic and long-distance magnonic soliton information transfer.
A numerical study on unsteadiness of vertical flow around a horizontal heated square cylinder with variable thermal buoyancy
Authors: Yazdani Shima , Salimipour Erfan , Sheremet Mikhail , Ghalambaz Mohammad
Published: November 2024

Analyzing the unsteadiness of flow is crucial due to its significant influence on flow characteristics, and at times, it can even alter the flow pattern entirely. In this research, the effects of two distinct types of unsteadiness—thermal buoyancy and vortex shedding—were examined in the context of laminar flow around a square cylinder. Initially, the impact of each unsteady phenomenon on the flow was studied independently. Subsequently, the combined influence of both unsteady factors on the flow was assessed. The Navier–Stokes equations are solved using a finite-volume approach, which discretizes the computational domain into small control volumes. This technique integrated a pressure-based method with a symmetry-preserving technique, which minimizes numerical diffusion, making it well-suited for accurately capturing flow instabilities. An in-house solver was developed specifically for this purpose. The calculations were conducted for Richardson numbers (Ri) ranging from 0 to 0.35 and for three different Prandtl numbers (Pr) of 0.2, 0.7, and 2.5, all at a Reynolds number (Re) of 100. Vortex shedding, referred to as type 1 unsteadiness, occurs naturally at Re = 100. To induce type 2 unsteadiness, Richardson numbers were varied according to a sinusoidal equation. The findings revealed that the drag coefficient of the cylinder is significantly affected by the frequency of Richardson numbers' variation. As the variation frequency decreased, the difference in drag coefficients during the increasing and decreasing phases of Ri also diminished.
Adaptive aperture pupil-inspired foveated single-pixel imaging for multi-posture moving targets
Authors: Xue Yihao , Wang Guan , Cai Yu , Deng Huaxia , Gong Xinglong
Published: November 2024

In nature, animals have evolved various shapes of pupils to detect moving targets with diverse postures effectively. Motivated by the concept of the adaptable aperture pupil, we present a pupil-inspired foveated single-pixel imaging approach featuring a variable foveal, enhancing the correlation between the fovea regions and targets in the scene. Furthermore, this pupil-inspired foveated strategy not only regulates the field of view by mimicking the expansion and contraction of the iris but also aids in target tracking by foveal saccade mimicry. In this way, our method improves the maximum utilization of high-resolution areas by 63%. The methodologies outlined in this study optimize the arrangement of pixel cells during the sampling process and promise to be a practical method enabling single-pixel imaging in dynamic scenes.
Synergistic effects of interstitial and substitutional doping on the thermoelectric properties of PbS
Authors: Wu Benteng , Zhao Xueke , Jia Mochen , Yang Dawei , Liu Yu , Song Hongzhang , Wang Dongyang , Cabot Andreu , Li Mengyao
Published: November 2024

Lead sulfide (PbS) is widely recognized as a promising n-type thermoelectric material for use in the middle-temperature range. Although it already exhibits favorable electronic and thermal properties, its thermoelectric performance could be further enhanced by addressing the disparity between the light and heavy bands in the conduction band, thereby optimizing electrical transport, and by modifying the strength of its chemical bonds to reduce lattice thermal conductivity. In this study, we demonstrate that introducing just small amounts of antimony (Sb) into PbS generates a unique combination of interstitial and substitutional doping that leads to a significant improvement in both directions. Substitutional doping enhances the degeneracy between the light and heavy bands, increasing carrier mobility. At the same time, interstitial doping introduces a new resonance state near the Fermi level, providing an additional channel for electron transport while boosting carrier concentration. These synergistic effects lead to a marked increase in the power factor of PbS, achieving an average power factor (PFavg) of 1.07 mW m−1 K−2 across the temperature range of 320–873 K. Moreover, Sb substitution for Pb induces a shift in the surrounding S atoms toward Sb, weakening their bonds with neighboring Pb atoms. This shift results in a coexistence of strong and weak chemical bonds, which effectively reduces lattice thermal conductivity. Additionally, the defect structures introduced by Sb doping effectively scatter phonons, further lowering lattice thermal conductivity. As a result, PbS doped with 0.5% Sb exhibits a figure of merit (ZT) of 0.73 at 873 K, which is approximately three times higher than that of undoped PbS.
On the wake of two transversely co-rotating inline spheres in a uniform flow
Authors: Kumar Abhishek , Das S. P. , Tiwari Shaligram
Published: November 2024

Uniform flow past two transversely (axes perpendicular to the flow direction) co-rotating inline spheres has been numerically investigated with the help of OpenFOAM. Three-dimensional numerical computations are performed for a fixed Reynolds number (Re) of 300, defined based on free stream velocity (U∞) and sphere diameter (D). Both the spheres are rotated about negative Z-axis with equal angular velocities. The angular velocity (ω*=ωD2U∞) of spheres is normalized with free stream velocity (U∞) and sphere diameter (D) and takes values between 0 and 1. The non-dimensional spacing S between spheres has been varied from 0.25 to 3. It is observed that the two rotating inline spheres modify significantly the wake characteristics of either sphere when compared with that of a single rotating sphere. For S = 0.25 and 0.5 and ω* ≤ 0.8, the wakes of both upstream and downstream spheres are found to be steady and characterized by double-thread wake structures. On the other hand, for S = 2, both the wakes are unsteady with hairpin vortices being shed in the downstream direction for which the mechanism of vortex formation depends on the range of values of ω*. Similar distinct mechanisms of vortex shedding as a function of ω* have also been observed for S = 3. For S = 1, it is observed with the help of Hilbert Huang transform that nonlinearity associated with unsteady wakes grows monotonously with the increase in ω* but shows non-monotonous variation for S = 2 and 3. For each value of S and ω*, drag force on both the spheres is found to be less than that for an isolated rotating sphere. The wake Strouhal number of either sphere is also found to be less than that for a single rotating sphere.
Interplay of pore geometry and wettability in immiscible displacement dynamics and entry capillary pressure
Authors: Zhou Tongke , Vasheghani Farahani Mehrdad , An Senyou , Niasar Vahid
Published: November 2024

Recent studies highlight the significant role of pore geometry and wettability in determining fluid–fluid interface dynamics in two-phase flow in porous media. However, current entry capillary pressure equations, rooted in the Young–Laplace equation, consider only cross-sectional details and apply wettability data measured on flat surfaces to complex three-dimensional (3D) pore structures, overlooking the coupled effect of contact angle and pore morphologies along the flow direction. This study employs the volume-of-fluid method to investigate the following: (a) How do combined effects of pore geometry and wettability control capillary pressure change, displacement efficiency, and residual saturations? (b) Can continuous two-phase flow be achieved at the pore scale? Through direct numerical simulations in constricted idealized-geometry capillary tubes and real pore structures, we vary the contact angle to characterize its impact on fluid–fluid interface morphology, entry capillary pressure (pce), and displacement efficiency. Our results show that during the drainage, pce temporarily decreases/turns negative under intermediate wettability conditions due to forced curvature rearrangement/reversal in the converging section. Local orientation angles along the flow direction are important in controlling the interface morphology and pce evolution. Moreover, intermediate contact angles enhance displacement efficiency due to curvature reversal, while insufficient corner flow during imbibition causes pore snap-off of the receding fluid, leading to higher residual saturation. The results challenge conventional methods in predicting entry capillary pressure, highlighting the need for incorporating 3D geometry in predictive models. Eventually, the insights underscore the importance of considering corner flow in controlling displacement efficiency within constricted geometries in pore network modelling studies.
Physical properties and thermal stability of zirconium platinum nitride thin films
Authors: Gallivan R. A. , Manser J. , Michelini A. , Toncich N. , Abando Beldarrain N. , Vockenhuber C. , Müller A. , Galinski H.
Published: November 2024

Ternary transition metal nitrides (TMNs) promise to significantly expand the material design space by opening new functionality and enhancing existing properties. However, most systems have only been investigated computationally, and limited understanding of their stabilizing mechanisms restricts translation to experimental synthesis. To better elucidate key factors in designing ternary TMNs, we experimentally fabricate and analyze the physical properties of the ternary Zr–Pt–N system. Structural analysis and density functional theory modeling demonstrate that Pt substitutes nitrogen on the nonmetallic sublattice, which destabilizes the rock salt structure and forms a complex cubic phase. We also show insolubility of Pt in the Zr–Pt–N at 45 at. % with the formation of a secondary Pt-rich phase. The measured reduced plasma frequency, decrease in resistivity, and decrease in hardness reflect a dominance of metallic behavior in bonding. Additionally, we observe the exsolution of Pt nano precipitates from the Zr–Pt–N films upon annealing as well as degradation in the nitridic film's thermal stability. Even at low concentrations (1%), Pt facilitates a solid reaction with the Si substrate that is otherwise inaccessible in ZrN films.
Experimental study of dam-break-like tsunami loads on the vertical structure with overhanging horizontal slab: Flat slab
Authors: Peng Chen , Chen Cheng , Nandasena N. A. K. , Deng Xin , Cai Feng , Guan Dawei
Published: November 2024

Tsunamis present a significant risk to coastal infrastructure. This study conducts a comprehensive experimental investigation into the effects of tsunami impacts on a vertical structure equipped with an overhanging horizontal slab. Dam-break waves were generated in the laboratory to simulate tsunami bore. The uplift pressure of the tsunami bore on the horizontal suspended slab and the horizontal pressure on the vertical wall were analyzed by combining experimental data with water flow patterns. The results revealed that the impact process could be categorized into four stages: initial impact, run-up, quasi-steady, and recession. Two characteristic pressures were identified: a maximum pressure during the initial impact stage and a quasi-steady pressure with a longer duration. The maximum uplift pressure was found to increase with the relative position and tsunami bore height. However, this trend was influenced by the slab height and gravity, particularly on the side of the slab closest to the wall. As the slab height increased, the water flow reflection area expanded, diminishing the focusing effect caused by the slab and decreasing the quasi-steady uplift pressure. The uplift coefficient was observed to decrease with an increase in the relative slab height, and a new uplift coefficient envelope was proposed based on experimental data and published articles. Equations for the uplift pressure distribution and a novel conversion method between uplift pressure and horizontal pressure were introduced. Furthermore, based on the measured data and existing theories, equations for estimating the maximum and quasi-steady uplift pressures are presented and validated using published data. These findings provide valuable insights into understanding and estimating the impact of tsunami on structures.
Temperature dependent electrocaloric performances in Pb0.97La0.02(Hf0.92Ti0.08)O3 antiferroelectric ceramic with triple phase structures
Authors: Yu Mengjiao , Wu Dandan , Dai Changshun , Long Mingsheng , Shan Lei , Wang Chunchang , Li Feng
Published: November 2024

Antiferroelectric–ferroelectric phase transition in antiferroelectric (AFE) materials usually triggers high-performance electrocaloric effect (ECE), as represented by PbZrO3-based AFE. As an isostructure to PbZrO3, EC research in PbHfO3-based AFE ceramics are significantly left out. In this work, temperature dependent electrocaloric performances in Pb0.97La0.02(Hf0.92Ti0.08)O3 with typical AFE features are explored, and rhombohedral ferroelectric (FER), AFE1 (A1, Pbam), and AFE2 (A2, Imma) triple phases are induced as temperature increases. This leads to dual coexisting regions with FER-to-A1 and A1-to-A2 at a temperature of ∼20 °C and ∼100 °C, respectively, where local EC maxima are produced with an ΔT ∼0.06 K and ΔT ∼0.16 K (E = 70 kV/cm). These are certified by comprehensive characterizations of in situ x-ray diffractometer, AFE electrical properties, and Raman spectra analysis. This strongly indicates that AFE (Pbam)-to-AFE (Imma) phase transition could efficiently optimize ECE in PbHfO3-based AFE, in addition to the conventional understandings of FE–paraelectric and AFE–paraelectric modulation strategy. This work not only presents the potential of PbHfO3-based AFE in solid-state cooling applications but also serves as a catalyst for further seeking for high-EC AFE materials.
Changing large wildfire dynamics in the wildland–urban interface of the eastern United States
Authors: Weidig Noah C. , Wonkka Carissa L. , Ivey Michaella A. , Donovan Victoria M.
Published: November 2024

Background The recent increase in large wildfires in the eastern United States makes it crucial to examine the subsequent risk to human life and property. In the eastern US, the wildland–urban interface (WUI), where wildfire risk is greatest, has expanded tremendously over the last three decades. Aims This study aimed to understand how increasing wildfires in the eastern US are manifesting in the WUI. Methods We quantified WUI growth and characterised large (>200 ha) wildfire regimes inside and outside the WUI at multiple spatial scales across the eastern US between 1986 and 2021. Key results WUI wildfires in the eastern US comprised 45% of all large wildfires and 55% of the area burned, were on average 46% larger than non-WUI wildfires, and are becoming more frequent in spring. Most increases in wildfire number and area burned occurred outside of the WUI. Conclusion The WUI plays an important role in large wildfire dynamics in the eastern US; however, increases in the number of large wildfires have occurred primarily outside the WUI. Implications Our findings highlight important interactions between human development and large wildfire occurrence in the eastern US and should be used to direct future region-specific assessments of changing wildfire risk.
Childhood exposure to coethnics increases naturalization
Authors: Kruse Mathias
Published: November 2024

In Europe, the tendency among immigrants and descendants to seek out and interact with other coethnics has raised concern for their integration as it can reduce contact with the ethnic majority. Though policymakers implement large-scale integration programs to counteract these trends, it remains empirically and theoretically ambiguous whether exposure to coethnic peers impedes integration, and causal evidence is more limited for the growing population of migrant children. In this article, I use high-quality Danish administrative panel data over 28 y to investigate whether the ethnic composition experienced in childhood among immigrants and descendants with a non-EU background affects a core behavioral indicator of integration: naturalization. To isolate the causal effect of the childhood ethnic composition, I use the quasi-experimental assignment of siblings into different school grades in the same school. I find that being exposed to coethnic peers in the school grade
increases
the probability of naturalizing later in life. The main explanation is that exposure to some coethnic peers improves academic skills which are positively correlated with citizenship acquisition. These findings demonstrate the causal importance of non-EU migrant children’s social environment for their later integration into the national community showing that the modest presence of coethnic peers can be a precondition for, not a barrier to, integration.
Genetic risk factors for Mesoamerican nephropathy
Authors: Friedman David J. , Leone Dominick A. , Amador Juan José , Kupferman Joseph , Francey Lauren J. , Lopez-Pilarte Damaris , Lau Jorge , Delgado Iris , Yih W. Katherine , Salinas Alejandro , Wang Minxian , Genovese Giulio , Shah Shrijal , Kelly Jessica , Tattersfield Calum F. , Raines Nathan H. , Amador Magaly , Dias Leny , Pitsillides Achilleas , Ramirez-Rubio Oriana , Amador Alda G. , Cortopassi Marissa , Applebaum Katie M. , Alper Seth L. , Banks Alex S. , McClean Michael D. , Leibler Jessica H. , Scammell Madeleine K. , Dupuis Josée , Brooks Daniel R.
Published: November 2024

Mesoamerican nephropathy (MeN) is a progressive kidney disease found on the Pacific coast of Central America primarily in young male agricultural workers without typical kidney disease risk factors. While it is generally accepted that environmental exposures contribute to MeN, we hypothesized that there was also an important genetic component. We performed a genome-wide association study comparing individuals with MeN versus individuals with normal kidney function. We found that Native American ancestry was strongly associated with increased risk of MeN. We also identified candidate variants in the
OPCML
gene, which encodes a protein that binds opioid receptors, that were associated with ~sixfold reduced odds of MeN (allele frequency 0.029 in controls and 0.005 in cases, OR = 0.16;
P
= 4 × 10
−8
). Sugarcane workers with the protective
OPCML
variants had markedly increased urine osmolality suggesting greater ability to defend against hypovolemia. Experiments with
Opcml
knock-out mice revealed roles for
OPCML
in fluid balance and temperature regulation consistent with our findings in humans. Our data suggest that heritable differential sensitivity to heat stress and dehydration contributes to high rates of kidney disease in Central America.
Structural basis for the synergetic neutralization of hepatitis E virus by antibody–antibody interaction
Authors: Zheng Minghua , Zhou Lizhi , Huang Yang , Zhang Xiao , Yu Zihao , Yang Chengyu , Chen Yuanzhi , Ying Dong , Wang Hong , Chen Zhenqin , Liu Chang , Tang Zimin , Wang Siling , Wang Kaihang , Yang Kaixiang , Lin Yanqing , Li Tingting , Zheng Qingbing , Zheng Zizheng , Zhang Jun , Yu Hai , Li Shaowei , Gu Ying , Xia Ningshao
Published: November 2024

Neutralizing antibodies (nAbs) play a crucial role in virology, antibody drug development, and vaccine research. In this study, we investigated the synergistic effect of two hepatitis E virus (HEV) nAbs, 8H3, and 8C11, which have exhibited enhanced neutralizing activity in a rhesus monkey model. We presented crystal structures of 8H3 Fab alone and a triple complex of 8C11 Fab and 8H3 Fab simultaneously binding to the HEV E2s protein (8C11:E2s:8H3). Through structural analysis, we identified critical binding sites and fully elucidated the binding footprints of nAb 8H3 in the 8C11:E2s:8H3 complex using site-directed mutagenesis, pinpointing Ile 529, Glu 549, Lys 554, and Ser 566 in the E2s domain, and K66H, S67H, D88H in the 8C11 heavy chain. Interestingly, the synergetic enhancement of 8C11 to 8H3 converted to an antagonistic effect when 8C11 bound to E2s with pretreatment of 8H3, indicating a unidirectional synergistic effect associated with the sequence of antibody involvement. We demonstrated this phenomenon through structural comparisons of E2s:8C11 vs. 8C11:E2s:8H3 crystal structures and molecular dynamics simulations, found that Ile 529 played a key role in the synergistic interplay between these two nAbs. The two-antibody combination showed a more potent antibody-imposed physical disruption mechanism and enhanced coneutralization in an authentic HEV-based cell model. Our study suggests a strategy for synergistic antibody cocktail design with antibody–antibody side-by-side interaction.
Uncovering the mechanical secrets of the squirting cucumber
Authors: Box Finn , Moulton Derek E. , Vella Dominic , Bhagotra Yuvraj , Lowe Tristan , Goriely Alain , Thorogood Chris J.
Published: November 2024

Rapid movement is rare in the plant kingdom, but a prerequisite for ballistic seed dispersal. A particularly dramatic example of rapid motion in plants is the squirting cucumber (
Ecballium elaterium
) which launches its seeds explosively via a high-pressure jet. Despite intriguing scientists for centuries, the exact mechanism of seed dispersal and its effect on subsequent generations remain poorly understood. Here, through a combination of experimentation, high-speed videography, quantitative image analysis, and mathematical modeling, we develop a full mechanical description of the process. We quantify the turgor pressure driving ballistic ejection, and uncover key mechanical interactions between the fruit and stem both prior to and during seed ejection, including the unique feature that fluid is redistributed from fruit to stem prior to ejection, a developmental event that goes against the paradigm of rapid seed ejection but which is of key importance in successful dispersal for
Ecballium
. Combining modeling elements, we quantify and simulate the ballistic trajectories of seeds, which are dispersed over distances greater than 2,000 times their length. We demonstrate how together these mechanical features contribute to a nearly uniform distribution of seeds away from the parent plant. Parametric variation of key developmental events in the modeling framework indicates how a suite of adaptive features in combination drives the spatial distribution of offspring over consecutive generations, and suggests that ballistic seed dispersal has a stabilizing effect on population dynamics by reducing intraspecific competition.
Recurrent DNA nicks drive massive expansions of (GAA)
n
repeats
Authors: Li Liangzi , Scott W. Shem , Khristich Alexandra N. , Armenia Jillian F. , Mirkin Sergei M.
Published: November 2024

Over 50 hereditary degenerative disorders are caused by expansions of short tandem DNA repeats (STRs). (GAA)
n
repeat expansions are responsible for Friedreich’s ataxia as well as late-onset cerebellar ataxias (LOCAs). Thus, the mechanisms of (GAA)
n
repeat expansions attract broad scientific attention. To investigate the role of DNA nicks in this process, we utilized a CRISPR-Cas9 nickase system to introduce targeted nicks adjacent to the (GAA)
n
repeat tract. We found that DNA nicks 5′ of the (GAA)
100
run led to a dramatic increase in both the rate and scale of its expansion in dividing cells. Strikingly, they also promoted large-scale expansions of carrier- and large normal-size (GAA)
n
repeats, recreating, in a model system, the expansion events that occur in human pedigrees. DNA nicks 3′ of the (GAA)
100
repeat led to a smaller but significant increase in the expansion rate as well. Our genetic analysis implies that in dividing cells, conversion of nicks into double-strand breaks (DSBs) during DNA replication followed by DSB or fork repair leads to repeat expansions. Finally, we showed that 5′ GAA-strand nicks increase expansion frequency in nondividing yeast cells, albeit to a lesser extent than in dividing cells.