bluuebunny/crossref_metadata_2025 huggingface dataset:
Technology for the development of residual reserves by water-gas methods in conditions of associated petroleum gas shortage
Authors: Drozdov Alexander , Gorelkina Evgeniya
Published: November 2024

A method for injecting a water-gas mixture is proposed, which takes into account the distribution of reserves in a formation anisotropic in permeability. A schematic diagram of a device for pumping a mixture into a formation is presented. The proposed technology is based on obtaining a water-gas mixture with maximum gas content. This requires a device consisting of several pump-ejector systems. Booster pump-ejector systems pump a water-gas mixture saturated with oil gas into selected wells that open up significant volumes of residual reserves. In areas with small volumes of reserves, it is proposed to inject solutions of chemical reagents to release carbon dioxide in the formation. This solution will increase oil recovery by implementing the injection of the mixture in the most rational way and reduce damage from associated gas flaring. For greater efficiency of water-gas mixture injection, it is necessary to select the composition of the water-gas mixture (the composition of water and the injected gas), which helps to suppress the coalescence of gas bubbles in the conditions of the selected field. In order to clarify the injection parameters, it is recommended to conduct mineralization studies and studies of the settling rate of the water-gas mixture column depending on the composition of the injected gas.
Analysis of the effectiveness of using complex probing signals to range ambiguity suppression in space monitoring systems
Authors: Khramov Konstantin , Zhiganov Sergey , Smirnov Mikhail , Zhiganova Elena
Published: November 2024

To improve the range resolution, it is necessary to expand the capture band. However, this leads to range ambiguity interference. This problem is especially serious in space view systems. Therefore, methods of reduction of ambiguity interference are an important part of the information processing system. In modern SAR systems, chirp signals are usually used as probing signals. However, other broadband signals with frequency modulation or PSK signals with different laws of intra-pulse modulation can be used to obtain a radar image. The aim of the work is to analyze the effectiveness of using complex probing signals to reduce range ambiguity interference in space-borne radar systems. In this work, models of radio holograms and radar images of a point target based on chirp signals, signals with hyperbolic and V-shaped frequency modulation are obtained. The results of processing probing chirp signals with pulse-by-pulse change of frequency signs, as well as BPSK signals and ensembles of BPSK signals are also considered.
Forecasting coastal systems based on satellite images
Authors: Panasenko Natalia , Sukhinov Alexander
Published: November 2024

In the Southern region of Russia, biotic, biological and anthropogenic factors are constantly in effect. To simulate various options for the development of biological and geophysical processes in marine and coastal systems, there is a need to develop and create non-stationary spatially heterogeneous interconnected mathematical models. For practical application of the models, real input data (boundary and initial conditions) and information on the initial parameters are required. This information can be obtained using spacecraft. This paper presents the developed software and algorithmic tools for recognizing space images, based on a combination of methods - local binary patterns (LBP) and neural network technologies. Initial data based on space images are entered into the computer model, which provide high accuracy in determining the state of coastal systems. This model can be used to predict possible changes in coastal ecosystems and develop strategies for their protection. The obtained research results open up significant prospects for preventing and reducing the negative consequences of adverse natural phenomena, including intensive “blooming” of water, reducing the calculation time by 20-30%, which provides specialists with a more rapid response to environmental changes. Thus, the research results open up new opportunities for improving the quality and effectiveness of environmental forecasts.
Modeling of radiation effects at the physical and technological level in the IET CAD
Authors: Zolnikov Konstantin , Shmakov Evgeny , Artemiev Andrey , Prykina Larisa
Published: November 2024

The article considers the issues of energy distribution and use management by means of modeling changes in the electrophysical characteristics of semico nductor structures under the influence of static radiation. The change in the main electrical parameters of transistor structures is given, such as, change in the concentration of the main charge carriers, change in specific resistance, change in the mobility of charge carriers, change in threshold voltage, change in the lifetime of charge carriers. Also in the article within the framework of changing other parameters of transistors the following calculations are carried out: change in the slope of the drain-gate characteristic, change in the leakage current in the drain circuit, thermal generation current, surface leakage current, change in input resistance.
Possibilities of creating hydroplaning vessels with a transverse redan
Authors: Minaev Anton
Published: November 2024

One of the possible ways to increase the speeds of high-speed gliding ships, boats, boats is the creation and use of cross-edges on the bottom of the vessel. In addition to solving the objective of increasing speed while reducing friction (resistance), the objective of more economical running is solved, as well as the creation of dynamic stability of the vessel possessing bottom contours with transverse redan. Due to the complexity of the objective solution and lack of theoretical models, the issues related to the solution of dynamic stability of ships at the occurrence of auto oscillations - the so-called “dolphinization”, were studied on the basis of experimental data and empirical dependences obtained for the first time. To obtain experimental data, a model of a boat with a transverse redan was created and tested in full-scale conditions. According to the obtained records and results of measurements, the boat on a low-power motor reached a speed of 50 km per hour, and entered the mode of operation of the transverse redan. The tested boat model showed a dynamically stable character of motion. When using the transverse redan boat motion, the wetted surface of the boat was significantly reduced, resulting in less friction between the boat and the water and the possibility of using a more economical mode of boat motion.
Inreasing the engine powers by using brown’s gas
Authors: Nasirov Ilham , Nurdinov Murodali , Rakhmonov Khurshidbek , Isakulova Nilufar
Published: November 2024

Tests of Braun gas obtained from electrolyzers in laboratory and road conditions in various models of «UzAvtomotors» XJ engine installed stands and carried out in cars. According to the results of laboratory tests, a small type of electrolyzer was selected. In field tests, the option of adding 15 % of Brown’s gas released from the internal electrolyzer to the fuel-air mixture was selected. According to the results of the tests, the power of the engine increases by 5.49%, the time for the car to reach 100 km/h decreases by 6.75%, the maximum speed of the car increases by 10.42%, the amount of CO in the exhaust gases is 64.67 decreases by % and the amount of CH in the treated gases decreases by 66.04%. Also, the mileage of the car on the given fuel increases by 1.15-1.18 times, and the life of the engine increases by 1.3-1.4 times due to the automatic removal of carbon soot from the engine.
Modeling of technological unit of methanol formalin production with vortex type absorber integration
Authors: Moskalev Leonid
Published: November 2024

The study shows the problem of gaseous emissions in the production of technical formalin. A digital twin of the technological scheme of technical or methanol formalin production is constructed. Methods and ways to reduce methanol in gaseous emissions are shown. The modernized version of the technological scheme of water-methanol methanal solution absorption with process optimization is presented. A comparative justification of the adequacy of the presented model is carried out by comparing the industrial material balance with the material balance of the numerical model. The error between the industrial and calculated data was not more than 15%, which confirms the adequacy of the constructed model in the Aspen Hysys environment. The results are also shown when changing some technological characteristics of the process, which require additional not small costs. And advantages of application of vortex type absorber as an additional absorption stage are shown. Such implementation will also require additional costs, but the cost of vortex type absorber is one order of magnitude lower than the cost of dynamic equipment. At the same time, the methyl alcohol captured in the vortex absorber can be returned to the initial stage of the technological process, thus reducing the environmental load and increasing resource and energy saving at formalin production facilities.
Characteristics of Mode Choice of Student Transportations: A Policy Approach for Safer School Commutes
Authors: Kelana Diwa Jaya , Hardianto Dani , Sarjana Sri , Hanun Jalilah
Published: November 2024

The use of private vehicles dominates travel compared to public transportation which has a significant impact on students’ routine trips to school. The use of private vehicles by students, especially those without a driver’s license is still very high. Despite the availability of alternatives, a gap exists in understanding students’ transportation preferences and potential demand for safer options. In light of the fact that accidents among students contribute to the highest number of accident cases. This study aims to provide recommendations for alternative transportation for students in Majalengka as a form of policy intervention, through analysis using the multinomial logistic regression method. This analysis identifies variables that influence the choice of transportation mode based on statistical principles. then models and calculates potential demand based on existing scenarios. The results of analysis show the value of potential demand for various alternative transportation modes other than private vehicles such as electric bicycles, school transportation, and public transportation. with the highest potential demand for school transportation modes. Therefore, the implementation plan for alternative transportation for students needs to be considered from quantitative and legal aspects, adjusted to the priority scale and level of urgency set by stakeholders responsible for transportation in the local government.
Prospects for New Physics in Kaon Decays
Authors: Polonsky Zachary
Published: November 2024

In these proceedings, we give an overview of the current status and future prospects of new physics searches using rare kaon decays. We discuss several promising observables whose experimental or theoretical precisions can be reasonably–and in several cases substantially–reduced in the near future. We emphasize the complimentarity of charged and neutral kaon programs in their ability to both probe a wide array of new physics scenarios and test qualitatively different physics.
Bottomonium and exotic spectroscopy
Authors: Garg R.
Published: November 2024

This proceedings summarize the most recent measurements of exotic bottomonium states to probe the fundamentals of QCD at the Belle, Belle II and LHCb experiments.
Recent CP violation and lifetime results from CMS
Authors: Sergeychik Vladimir
Published: November 2024

Recent results on CP violation in charm and beauty sector, as well as lifetime measurements, by the CMS experiment at the LHC are presented. The first measurement of CP violation in charm by CMS is reported, as well as the most precise measurement of effective lifetime $${\tau (B_s^0 \to J/\psi K_S^0)} $$ and the first evidence for CP violation in the $${B_s^0} $$ → J/ψ ϕ(1020) → μ+ μ−K+K− decay. The analyses are based on 13 TeV proton-proton collision data.
Gestes techniques : l’ulcère superficiel chronique
Authors: Caillon Adrien , Douet Jean-Yves
Published: November 2024

L’ulcère superficiel chronique est une affection fréquente en ophtalmologie canine reposant sur l’apparition d’anomalies structurelles du complexe épithélio-basal. Son diagnostic se base sur une démarche rigoureuse et systématisée, et sa prise en charge est avant tout chirurgicale. Le choix du traitement dépend du matériel à disposition et des préférences du praticien et doit permettre le rétablissement d’un épithélium sain et pérenne, une fois la cicatrisation avérée.
Natural fluctuations of the tunnel current in Josephson junctions
Authors: Landa P. S. , Tarankova N. D.
Published: November 2024

The natural fluctuations of the tunnel current in Josephson junctions due to scattering of quasiparticle excitations by phonons in superconductors which form such a junction are analyzed. The spectra of natural fluctuations of the quasiparticle current, of the critical current, and of the Josephson-current frequency are calculated. An expression is derived for the natural width of the Josephson-current line, which is then evaluated and compared with the experiment.
Josephson effect in tunnel junctions with vanadium and vanadium oxide
Authors: Yanson I. K. , Rybal’chenko L. F.
Published: November 2024

A study was made concerning the characteristics of the Josephson effect in V−VxOy−Pb tunnel junctions. The results reveal that the critical current Ic in zero field is anomalously low and corresponds to the conductivity of an S1−I−S2 channel in parallel with an N−I−S2 channel. The dependence of the critical current on the magnetic field intensity signifies a barrier layer which is very homogeneous in the junction plane. The anomalous Ic(T) characteristic as well as the temperature dependence of the period of Ic(H) oscillations suggests that the value of the order parameter in vanadium films near the barrier depends on the coordinates here. A comparison with the characteristics of V−Al−AlxOy−Pb junctions (with dAl ∼ 100 Å) indicates that the presence of vanadium oxide lowers the value of the superconducting order parameter in the vanadium film. The intrinsic step shape of the current-voltage characteristics is analyzed here and the corresponding parameters are used for independently determining the depth to which the magnetic film penetrates the vanadium film.
Mechanism of magnetic field induced enhancement of luminescence in antiferromagnets
Authors: Eremenko V. V. , Matyushkin E. V. , Shapiro V. V. , Bron R. Ya.
Published: November 2024

The luminescence of an antiferromagnetic KMnF3 crystal has been investigated in magnetic fields up to 260 kOe, The glow enhancement observed is explained in terms of the exciton model, taking into account the noncollinearity of the magnetic structure induced by the external field.
Dynamics of impurity spin with rapid spin relaxation of ferromagnet
Authors: Los’ V. F.
Published: November 2024

Using the superoperator method, a complete and rigorous solution is obtained for the dynamics of a weakly bound impurity spin in a ferromagnet, in the case of rapid spin relaxation of the matrix atoms. The expressions obtained for the spectral representation of the correlation functions of the impurity spin are valid for any relation between the line-shape parameters of the impurity-excitation spectral distributions, for any spin of the impurity, and in a wide range of temperatures (up to values close to the Curie point). The parameters of the spectral distribution of the impurity-spin correlation functions are expressed in terms of the correlation functions for matrix-atom spins of ferromagnets without impurities.
Excitation of coupled branches in homogeneous antiferromagnetic resonance in CuCl2·2H2O in an inclined magnetic field
Authors: Galkin A. A. , Vetchinov A. V. , Dan'shin N. K. , Popov V. A.
Published: November 2024

A study has been made of a homogeneous spin-spin resonance in the antiferromagnet CuCl2·2H2O in the spin-reversed state; branches of the coupled oscillations for the magnetization and antiferromagnetism vectors have been observed, and their dependence on temperature and magnetic-field inclination to the easy axis has been investigated. The measurements agree satisfactorily with theory for the region below 2.5°K and allow one to establish the parameters and the magnetic-anistropy field.
X-ray investigation of the structure of solid hydrogen
Authors: Grushko V. I. , Krainyukov V. I. , Krupskii I. N. , Stetsenko Yu. E. , Shcherbakov G. N.
Published: November 2024

An x-ray investigation was made of solid hydrogen at pressures of 80–100 atm. It is shown that the phase transition observed at these pressures in the region of premelting temperatures is connected with the transition of H2 from a hexagonal to the face centered cubic structure.
On the quantum theory of galvanomagnetic phenomena (GMP) in semimetals and semiconductors. I. Model of two standard bands
Authors: Kuleev I. G. , Novokshonov S. G. , Perevalov S. P.
Published: November 2024

Transverse galvanomagnetic phenomena in degenerate semimetals and intrinsic semiconductors in a quantized magnetic field are analyzed. Elastic scattering of current carriers by impurities with a short-range potential is taken into account not in a Born approximation. Cases of equal and unequal electron and hole concentrations are examined.
Electron Fermi liquid in thin metallic films with magnetic impurities
Authors: Kondrat'ev A. S. , Kuchma A. E. , Meilanov R. P.
Published: November 2024

The spectrum of collective excitations in thin metallic films with magnetic impurities is considered on the basis of the theory of the degenerate electron Fermi liquid. Oscillations of spin-wave frequencies are discussed as a function of the film thickness.
Kinetic equation taking into account the finite nature of the lifetime of thermal phonons and the thermal conductivity of dielectrics
Authors: Gurzhi R. N. , Maksimov A. O.
Published: November 2024

A theory is developed for the low-temperature thermal conductivity of dielectrics, in which the relaxation of longitudinal longwave phonons is determined by Simons' mechanism. A kinetic equation is obtained which takes into account the broadening of the energy spectrum associated both with collisions between thermal phonons and with their scattering by local defects of the crystal lattice. It is shown that longitudinal longwave phonons make a considerable contribution to heat transfer in bulk dielectric specimens. This leads to a change in the value of the coefficient of thermal conductivity and its dependence on temperature, impurity concentration, and other characteristic parameters of the problem.
Temperature dependence of ultrasound damping in cobalt single crystals
Authors: Taborov V. F. , Tarasov V. F.
Published: November 2024

The change in ultrasound damping in cobalt single crystals as a function of field in the range 4.2–300°K is studied. It was discovered that the observed maximum in ultrasound damping is produced by two mechanisms having different temperature dependences.
Theory of the Dingle factor due to dislocations
Authors: Ginsburg VI. L. , Maksimov A. O.
Published: November 2024

We study the effect of the long-range part of the dislocation potential on the decrease of the magnetic moment oscillation amplitude, i.e. on the de Haas-van Alphen effect. It is shown that the formula for the Dingle factor proposed by Watts ξd=〈exp{ih∫0Tπu(r(τ))dτ}〉 where TLaris the Larmor period, μ(r) is the dislocation potential, and τ is the “magnetic time” describing the electron motion along a classical orbit in the magnetic field, is valid provided kL2⪢R where k is the electron wave vector, L is the average distance between dislocations, and R is the Larmor radius.
High-frequency dislocation internal friction in bismuth single crystals at 4.2-300° K
Authors: Pal'-Val' P. P. , Platkov V. Ya.
Published: November 2024

Dislocation internal friction has been studied as a function of temperature (4.2–300°K), frequency (7.5–142.5 MHz), and amplitude. The temperature dependences indicate that dislocations contribute significantly to ultrasound absorption. An analytical method for separating loss mechanisms allowed us to find the frequency profile of overdamped dislocation resonance and to obtain the damping coefficient (B =3.1·10−4 dyn·sec·cm−2 at 300°K) for the {111} <101> dislocation system. At 4.2°K the amplitude dependence of absorption at the frequency of 7.5 MHz in the small-amplitude region, followed by a rising portion which goes over smoothly into a long plateau. When large-amplitude oscillations were excited absorption decreased in the amplitude-dependent region but remained unchanged in the amplitudeindependent region. In the amplitude-dependent region the absorption was found to depend on the number of large-amplitude pulses. The amplitude dependence at 4.2 °K is due to a thermal unpinning of dislocations; this makes it reasonable to compare the measured results with the predictions of the Granato-Liicke and Rodgers theories. The comparison lent support to these theories. As in the case of amplitude-independent losses, the absorption in the range of amplitudes near the maximum in the experiments is attributed to dynamic-type dislocation losses. In both cases these losses are determined by the same value of the damping coefficient but they increase sharply in the large-amplitude range owing to a power-law dependence on the dislocation-segment length which increases due to break-away from the pinning points. The bond strengths before and after excitation of large-amplitude oscillations were found to be in a 1:1.19 ratio.
Ground states of hexagonal antiferromagnets
Authors: Bar'yakhtar V. G. , Sobolev V. L.
Published: November 2024

A study has been made of the antiferromagnetism and the weak ferromagnetic-moment vectors in relation to the magnitude and direction of the external magnetic field applied in the basal plane of a hexagonal antiferromagnet. It is found that the reversal of the magnetic moments of the sublattices is substantially different from that in a uniaxial crystal and is due to stability loss in the metastable phase.
Investigation of flow field and convective heat transfer of narrow-clearance Taylor–Couette–Poiseuille flow with limited axial length
Authors: Lyu Yuan-wei , Zhao Yun-duo , Zhang Jing-yang , Liu Yuan , Huang Pu , Zhang Jing-zhou , Guo Yu
Published: November 2024

In industrial applications, Taylor–Couette–Poiseuille (TCP) flows are usually characterized by limited axial scope and eccentricity. The aerodynamic and thermal performance characteristics of these flows strongly depend on the coupling between the end leakage and axial throughflow. This study addressed the flow field and convective heat transfer characteristics of limited-length TCP flows (limited TCP flows); the rotational Reynolds number ranged from 590 to 1110, eccentricity ratio ranged from 0.3 to 0.7, dimensionless clearance height ranged from 0.016 to 0.04, and axial Reynolds number ranged from 0 to 70. Axial throughflow induced upstream movement of the high-pressure zone and downstream movement of the low-pressure zone along the axial direction, constituting a novel finding. The shearing flow's static pressure was sinusoidal in the angular direction, with the maximum and minimum at θ = 0.73π and θ = 1.08π, respectively. For 0.375 < Z/L < 0.625, the line-averaged Nusselt number remained almost unchanged, whereas it increased sharply near the end of the clearance. The pressure and the Nusselt number increased as the rotational Reynolds number, eccentricity, and axial Reynolds number increased, and decreased as the dimensionless clearance height increased. At Rea = 80, axial throughflow dominated the limited TCP flow. Compared with the limited Taylor–Couette flow, the axial throughflow increased the initial pressure of the gas film. In the central section, the angular distance between the maximal and minimal static pressures was smaller than for limited Taylor–Couette flow. The pressure and Nusselt number curves for the limited TCP flow were center-asymmetrical. Within the parametric range considered in this study, the limited TCP flow was almost laminar in the clearance, while it is highly turbulent as approaching to. Taylor vortices emerged near the clearance inlet but disappeared near the clearance outlet, distinct from the limited Taylor–Couette flow.
Efficient backward x-ray emission in a finite-length plasma irradiated by a laser pulse of picosecond duration
Authors: Yeh I.-L. , Tangtartharakul K. , Tang H. , Willingale L. , Arefiev A.
Published: November 2024

Motivated by experiments employing picosecond-long, kilojoule laser pulses, we examined x-ray emission in a finite-length underdense plasma irradiated by such a pulse using two-dimensional particle-in-cell simulations. We found that, in addition to the expected forward emission, the plasma also efficiently emits in the backward direction. Our simulations reveal that the backward emission occurs when the laser exits the plasma. The longitudinal plasma electric field generated by the laser at the density down-ramp turns around some of the laser-accelerated electrons and re-accelerates them in the backward direction. As the electrons collide with the laser, they emit hard x rays. The energy conversion efficiency is comparable to that for the forward emission, but the effective source size is smaller. We show that the picosecond laser duration is required for achieving a spatial overlap between the laser and the backward energetic electrons. At peak laser intensity of 1.4×1020 W/cm2, backward-emitted photons (energies above 100 keV and 10° divergence angle) account for 2×10−5 of the incident laser energy. This conversion efficiency is three times higher than that for similarly selected forward-emitted photons. The source size of the backward photons (5 μm) is three times smaller than the source size of the forward photons.
Transport properties of the partially ionized ionosphere
Authors: Pandey B. P. , Ieda A.
Published: November 2024

The level of ionization and transport properties in the Earth's E and F layers are interrelated and vary due to electron–neutral, ion–neutral, ion–ion, and ion–electron collisions at various altitudes. Mobility of the ions, or the ion–Hall parameter βi (given by the ratio of the ion–cyclotron to the collision frequency), determines the relative importance of the various (i.e., Ohm, Hall, and Pedersen) conductivities, parallel, perpendicular, and cross (with respect to the magnetic field) viscosities, and thermal conductivities. Whereas perpendicular viscosity and thermal conductivity due to ions are 1/βi2 smaller than the parallel ion viscosity, both the parallel and perpendicular viscosities and thermal conductivities due to neutrals are of the same order. Further, the perpendicular component of the viscosity and thermal conductivity are a weak function of ion–Hall parameter. Using the E and F layers' ionospheric data, we calculate various transport coefficients and show that the perpendicular transport coefficients are of the same order as the parallel transport coefficients. For completeness, we also give an expression for the Ohm, Hall, and Pedersen diffusivities, which could be important in the lower layer of the ionosphere.
Unstable flow analysis of transient process in the pump as turbine during turbine mode caused by pump power failure
Authors: Zhang Chenying , Pavesi Giorgio , Pei Ji , Wang Wenjie , Yuan Shouqi , Shen Jiawei
Published: November 2024

Mixed-flow pump as turbines (PATs) serve as pivotal components within energy micro-grids, facilitating energy conversion and storage. However, the emergence of pressure pulsations in these systems can markedly affect their stability and efficiency, especially in pump power failure. To simulate the power-off transition accurately, the commercial computational fluid dynamics code ANSYS CFX® is integrated by a Fortran program through ANSYS parametric design language in the transient simulation to enable real-time iterative calculations of angular momentum equations for mixed-flow PAT at varying speeds. This study integrates the analysis of radial forces, vortices, and flow lines to elucidate the sudden changes in pressure pulsations observed during the transition stages. Specifically, significant fluctuations in the amplitude of pressure pulsations at the volute tongue were found for various initial flow rates, which correlated closely with changes in radial forces. The sudden increase and nonuniform distribution of radial forces emerged as the main factors of these fluctuations. In addition, the study reveals that the intensity of pressure fluctuations evidenced by wavelet time-frequency analysis on the pressure surface of the blade significantly exceeds that on the back surface of the blade. Furthermore, in the flow characteristics inside the draft tube, the pressure pulsation signals are mainly concentrated in the low-frequency region and are accompanied by the presence of a double-helix structure. These results provide an important reference for further understanding of the operating mechanism of the mixed-flow pump as a turbine, which helps to optimize the design and improve the performance.
Acoustic forces near elastic substrate
Authors: Kleshchenko V. , Albitskaya K. , Petrov M.
Published: November 2024

In this work, we study the acoustic forces acting on particles due to sound scattering at the interface with an elastic substrate. Utilizing the Green's function formalism, we predict that excitation of a leaking Rayleigh wave results in a strong modification of the acoustic pressure force acting on a monopole scatterer and changes the equilibrium position of particles above the substrate surface. We also showed that the presence of a substrate changes the configuration of the acoustical binding of two particles due to multiple rescattering of acoustic waves from the interface. The reported results propose the method of acoustic manipulation via surface wave excitation and demonstrate the effect of elastic media in acoustical trapping of micro-objects.
Morphology- and crystal packing-dependent singlet fission and photodegradation in functionalized tetracene crystals and films
Authors: Goldthwaite Winston T. , Lambertson Evan , Gragg Madalyn , Windemuller Dean , Anthony John E. , Zuehlsdorff Tim J. , Ostroverkhova Oksana
Published: November 2024

Singlet fission (SF) is a charge carrier multiplication process that has potential for improving the performance of (opto)electronic devices from the conversion of one singlet exciton S1 into two triplet excitons T1 via a spin-entangled triplet pair state 1(TT). This process depends highly on molecular packing and morphology, both for the generation and dissociation of 1(TT) states. Many benchmark SF materials, such as acenes, are also prone to photodegradation reactions, such as endoperoxide (EPO) formation and photodimerization, which inhibit realization of SF devices. In this paper, we compare functionalized tetracenes R–Tc with two packing motifs: “slip-stack” packing in R = TES, TMS, and tBu and “gamma” packing in R = TBDMS to determine the effects of morphology on SF as well as on photodegradation using a combination of temperature and magnetic field dependent spectroscopy, kinetic modeling, and time-dependent density functional theory. We find that both “slip-stack” and “gamma” packing support SF with high T1 yield at room temperature (up to 191% and 181%, respectively), but “slip-stack” is considerably more advantageous at low temperatures (<150 K). In addition, each packing structure has a distinct emissive relaxation pathway competitive to SF, while the states involved in the SF itself are dark. The “gamma” packing has superior photostability, both in regards to EPO formation and photodimerization. The results indicate that the trade-off between SF efficiency and photostability can be overcome with material design, emphasize the importance of considering both photophysical and photochemical properties, and inform efforts to develop optimal SF materials for (opto)electronic applications.
Tribo-dynamic effects of machining caused surface waviness on a line contact
Authors: Ebrahimi E. , Li S.
Published: November 2024

Considering an elastohydrodynamic lubrication line contact, this study investigates the tribo-dynamic effects introduced by surface waviness. These waviness profiles are inevitable during various machining processes, such as grinding, and are on a larger scale than roughness. The waviness feature excites vibratory motions of contact bodies, and influences the lubrication performance through dynamic contact force and periodic squeezing. In this work, a tribo-dynamic formulation is implemented to examine such impact on film thickness, contact pressure, friction, and movement of the contact components. Owing to the presence of subharmonics, waviness introduced tribo-dynamic behavior cannot be eliminated within the adopted operating speed range. However, it is shown to be feasible to implement engineered waviness profile for lubrication performance improvement, providing a new and effective technique for friction/power-loss reduction, for instance.
An analytical investigation of liquid droplet deformation in a superposed electric field consisting of an alternating and a constant electric field
Authors: Mohanty Bikash , Bandopadhyay Aditya
Published: November 2024

The dynamics of a single droplet dispersed in a continuous medium that is subjected to a superposed electric field, which consists of an alternating and a constant electric field, is studied analytically. The closed analytical expression for the deformation of the droplet due to the superposed electric field is formulated at periodic steady state by considering small deviation from the equilibrium spherical shape of the droplet. The present study reveals that the mean deformation follows the same trend as the root mean square value of the applied electric field and the mean normal electric stress across varying mixing ratios of the superposed electric field. The deformation is frequency dependent, wherein mean deformation decreases with increasing frequency and attains a constant value at higher frequencies. This phenomenon correlates with changes in surface charge density and droplet–medium interface velocity. Furthermore, the influence of medium viscosity on deformation dynamics is elucidated, showing nominal effects on mean deformation but significant impacts on deformation amplitude. In highly viscous mediums, the electro-viscous stress is countered by viscosity of the medium thereby dampening oscillation amplitudes. The study confirms that the mean deformation is a weak function of the viscosity ratio of the droplet and the medium.
Convolutional neural network model-based prediction of human muscle activity by analyzing urine in body fluid using Raman spectroscopy
Authors: Liu Shusheng , Su Wei , Wang Zhenfeng , Wan Qihang , Luo Yinlong , Xu Xiaobin , Chen Liting , Wu Jian
Published: November 2024

In recent years, with the popularization of the concept of exercise, the determination of fatigue state during exercise in order to achieve the purpose of scientific exercise has become an important research topic. The concentration of urea in urine fluctuates with the change in exercise intensity, so it is widely used as a biochemical indicator for judging sports fatigue. In this paper, a method combining Raman spectroscopy and convolutional neural network is proposed for quantitative analysis of urea in urine. Averaged spectra are combined with the baseline correction of Raman spectra, an approach that significantly improves the quality of the data and further enhances the prediction accuracy of the model. Finally, in the actual quantitative analysis of urine urea, it demonstrated not only high efficiency and simplicity but also very high stability compared with the traditional optical colorimetric method. Thus, it provides a basis for the rapid and accurate assessment of muscle fatigue.
Numerical analysis of Reynolds and Mach number effect on dynamic stall onset
Authors: Lee Sunyoung , Chanez Bryan , Gross Andreas
Published: November 2024

The onset of dynamic stall limits the maximum airspeed of helicopters. For Reynolds numbers where laminar separation precedes transition, the bursting of a leading edge laminar separation bubble can initiate dynamic stall. Using large-eddy simulations, the effect of Reynolds and Mach number on bubble bursting is investigated for the National Advisory Committee for Aeronautics (NACA) 0012 wing section that is undergoing a harmonic pitching motion. Time histories of the lift and moment coefficient as well as the skin-friction and wall-pressure coefficient are compared for chord-based Reynolds numbers of 100 000, 200 000, and 400 000 and Mach numbers of 0.1 and 0.4. With increasing Reynolds number, the bubble size prior to bursting is diminished. For the larger Mach number, the bubble is larger and bursts earlier. To understand the observed behavior, spanwise and phase-averaged flow fields just prior to bubble bursting for Re = 100 000 are analyzed with a compressible biglobal stability computer program. The biglobal analysis reveals dominant two-dimensional modes for M = 0.1 and M = 0.4. For the higher Mach number, the growth rates are reduced, which explains the longer bubble. Observed oblique waves in the laminar separation bubble for M = 0.4 may result from the resonance of three-dimensional waves with two-dimensional shear layer waves.
Super-resolution reconstruction of propeller wake based on deep learning
Authors: Li Changming , Liang Bingchen , Wan Yingdi , Yuan Peng , Zhang Qin , Liu Yongkai , Zhao Ming
Published: November 2024

This paper proposes a super-resolution (SR) reconstruction method based on deep learning, which efficiently reconstructs the global high-resolution wake flow field from the low-resolution (LR) wake data of a propeller. The extensive wake data for the propeller under various operating conditions are generated using numerical simulations based on a delayed detached eddy simulation model. The proposed approach, propeller super-resolution convolutional neural networks (PSCNN), uses a dilated convolutional module to capture multi-scale spatial characteristics of wake flow fields. The performance of the proposed SR method is evaluated by improving the resolution of the wake flow field under different scaling factors, and its superiority is demonstrated by comparing the reconstruction accuracy with that of two other typical SR reconstruction methods. The results indicate that PSCNN can effectively improve the resolution of the propeller wake flow field by 32 times, with an overall mean relative error of the three velocity components being less than 4.0%, and the reconstructed global SR wake flow field agrees well with the ground truth in spatial distribution variation. Furthermore, PSCNN can reconstruct the SR wake flow field with reasonable accuracy under unseen operating conditions, further proving the generalizability of the proposed SR model in capturing spatial relationships of the propeller wake. Overall, the proposed SR reconstruction method has significant applications in obtaining high-resolution flow snapshots in fluid experiments.
Dynamic excellence in magnetorheological shear thickening fluid: Fabrication and formulation of a constitutive model
Authors: Wang Hanyan , Du Chengbin , Ge Maohui , Sun Liguo , Fu Yankai
Published: November 2024

Improving the dynamic rheological properties of magnetorheological shear thickening fluid is beneficial to its improved application in dampers. In this work, we mixed silicon dioxide (SiO2), carbonyl iron powder (CIP), and sepiolite (Sep) into polyethylene glycol to prepare a novel sepiolite magnetorheological shear thickening fluid (MR-Sep/STF). The dynamic rheological properties of the MR-Sep/STF and stress attenuation were studied through orthogonal array testing. Specifically, we mean that using this experimental design to evaluate the effects of varying proportions of SiO2, CIP, and Sep on the damping factor, dynamic yield stress, and shear thickening effect. The excellent performance of the MR-Sep/STF was achieved at an optimal ratio of 55% SiO2, 10% CIP, and 2% Sep. In addition, stress attenuation tests indicated that when the shear rate was within the range of 30–40 s−1, the stress attenuation is roughly between 42.85% and 59.78%. Once the shear rate exceeded 40 s−1, the stress decreased by more than 300%. Furthermore, we proposed a structural kinetics constitutive model that offers profound insight into the dynamic response mechanisms of the MR-Sep/STF: at the maximum shear rate, the structure generation rate a has a maximum value. Once maximum shear rate is exceeded, the structure decomposition rate b is greater than the generation rate a, and the viscosity and stress decrease macroscopically.
Evidence of long-distance movement of green sawfish (Pristis zijsron) in Western Australia
Authors: Ingelbrecht Jack , Allen Mark G. , Bateman Rebecca L. , Ebner Brendan C. , Fazeldean Travis , Krispyn Kurt N. , Lear Karissa O. , Lee Tegan , Lymbery Alan J. , McAuley Rory B. , Phillips Nicole M. , Whitty Jeff M. , Wueringer Barbara E. , Morgan David L.
Published: November 2024

Context In this study, single-nucleotide polymorphisms (SNPs) were used to investigate kinship for the green sawfish (Pristis zijsron). Aims To examine the relatedness of P. zijsron across an expansive coastline in Western Australia. Methods Sampling was conducted between the Fitzroy River estuary and Bay of Rest in the eastern Indian Ocean (north-western Australia) between 2003 and 2022. SNPs were generated from tissues collected from 137 live and 1 recently deceased P. zijsron. Key results Overall, 62 individual P. zijsron were assigned to 25 litters of full siblings, with litter sizes ranging from 2 to 5 pups, and 76 P. zijsron individuals were assigned to 96 half sibling pairwise relationships. Four pairs of half siblings were captured more than 500 km and born at least 6 years apart, including one pair of neonates captured ~870 km and 8 years apart, in the Ashburton River estuary (Pilbara) and Cable Beach (Broome). Furthermore, a pair of full-sibling pups (i.e. young of the year) caught at Cape Keraudren (Pilbara) in 2008 were half siblings of a pup caught in the Ashburton River in 2014. Conclusions This study provides evidence of long-distance, likely parental, movement of P. zijsron. Implications Dispersal of P. zijsron over large spatial scales indicates that populations could be replenished from elsewhere should they experience a decline, thereby reducing the risk of localised extinction for this species.
Agonist activation to open the Gα subunit of the GPCR–G protein precoupled complex defines functional agonist activation of TAS2R5
Authors: Young Yang Moon , Duy Mac Khuong , Strzelinski Hannah R. , Hoffman Samantha A. , Kim Donghwa , Kim Soo-Kyung , Su Judith , Liggett Stephen B. , Goddard William A.
Published: November 2024

G protein-coupled receptors (GPCRs) regulate multiple cellular responses and represent highly successful therapeutic targets. The mechanisms by which agonists activate the G protein are unclear for many GPCR families, including the bitter taste receptors (TAS2Rs). We ascertained TAS2R5 properties by live cell-based functional assays, direct binding affinity measurements using optical resonators, and atomistic molecular dynamics simulations. We focus on three agonists that exhibit a wide range of signal transduction in cells despite comparable ligand–receptor binding energies derived from direct experiment and computation. Metadynamics simulations revealed that the critical barrier to activation is ligand-induced opening of the G protein between the α-helical (AH) and Ras-like domains of Gα subunit from a precoupled TAS2R5-G protein state to the fully activated state. A moderate agonist opens the AH-Ras cleft from 22 Å to 31 Å with an energy gain of −4.8 kcal mol
−1
, making GDP water-exposed for signaling. A high-potency agonist had an energy gain of −11.1 kcal mol
−1
. The low-potency agonist is also exothermic for Gα opening, but with an energy gain of only −1.4 kcal mol
−1
. This demonstrates that TAS2R5 agonist-bound functional potencies are derived from energy gains in the transition from a precoupled complex at the level of Gα opening. Our experimental and computational study provides insights into the activation mechanism of signal transduction that provide a basis for rational design of new drugs.
In situ licensing of mesenchymal stem cell immunomodulatory function via BMP-2 induced developmental process
Authors: Zhu Fuwei , Ji Luli , Dai Kai , Deng Shunshu , Wang Jing , Liu Changsheng
Published: November 2024

The immunomodulatory function of mesenchymal stem cells (MSCs) is plastic and susceptible to resident microenvironment in vivo or inflammatory factors in vitro. We propose a unique method to enhance the immunoregulatory functions of mesenchymal stem cells (MSCs) through an artificially controllable in vivo inflammatory microenvironment generated by biomaterials loaded with BMP-2 that induce bone development. MSCs activated through this method effectively induce M1 macrophage polarization toward the M2 phenotype, promote differentiation of naïve T cells into regulatory T cells, and inhibit the proliferation of activated T cells via prostaglandin E2 (PGE2) secretion. This in vivo licensing not only preserves the immunogenicity of MSCs but also alters DNA methylation patterns, enabling MSCs to exhibit immunoregulatory effects with epigenetic memory. Validation in a mouse colitis model demonstrated their therapeutic efficacy and long-term viability. Furthermore, we found that the material composition influences the inflammatory response during development, with polysaccharide-based biomaterials proving advantageous over protein-based materials in establishing an inflammatory niche conducive to MSC activity. These findings underscore the potential of tissue engineering to create in vivo environments that license MSCs, offering a strategic avenue to enhance MSC-based therapies for addressing significant immune disorders.
The RING-type E3 ligase RIE1 sustains leaf longevity by specifically targeting AtACS7 to fine-tune ethylene production in
Arabidopsis
Authors: Tang Xianglin , Mei Yuanyuan , He Kaixuan , Liu Ran , Lv Xiaoyan , Zhao Yujia , Li Wenjing , Wang Qian , Gong Qinshan , Li Shengnan , Xu Chang , Zheng Xu , Cao Qingyu , Wang Dan , Wang Ning Ning
Published: November 2024

Ethylene is widely recognized as a positive regulator of leaf senescence. However, how plants coordinate the biosynthesis of ethylene to meet the requirements of senescence progression has not been determined. The rate-limiting enzyme in the ethylene biosynthesis pathway is ACC synthase. AtACS7 was previously considered one of the major contributors to the synthesis of “senescence ethylene” in
Arabidopsis
. However, the “brake signal” that fine-tunes the expression of AtACS7 to ensure optimal ethylene production during leaf development has yet to be identified. In the present study, the RING-H2 zinc-finger protein RIE1 was found to specifically interact with and ubiquitinate AtACS7, among all functional ACSs in
Arabidopsis
, to promote its degradation. Overexpression of
RIE1
markedly decreased ethylene biosynthesis and delayed leaf senescence, whereas loss of function of
RIE1
significantly increased ethylene emission and accelerated leaf senescence. The ethylene-related phenotypes of
RIE1
overexpressing or knockout mutants were effectively rescued by the ethylene precursor ACC or the competitive inhibitor of ACS, respectively. In particular, AtACS7-induced precocious leaf senescence was strongly enhanced by the loss of
RIE1
but was significantly attenuated by the overexpression of
RIE1
. The specific regions of interaction between AtACS7 and RIE1, as well as the major ubiquitination sites of AtACS7, were further investigated. All results demonstrated that RIE1 functions as an important modulator of ethylene biosynthesis during leaf development by specifically targeting AtACS7 for degradation, thereby enabling plants to produce the optimal levels of ethylene needed.