bluuebunny/crossref_metadata_2025 huggingface dataset:
Establishment of hydrolysates from enzymatic plant and fish protein by-products into fish nutrition
Authors: Koshak Zhanna V. , Grinko Anna N. , Buryakov Nikolai P. , Aleshin Dmitrii E.
Published: February 2024

The aim of this research was to scientifically prove the technology for producing plant-fish hydrolysates from sunflower meal and fish waste (carp processing) and to develop scientifically based recipes for protein hydrolysates and feed using it for carp of different ages. Compositions from fish waste and different amounts of sunflower meal have been developed, the chemical composition of the compositions and the digestibility of protein by carp have been studied. It was distinguished that the best characteristics when studing the nutritional value and digestibility of crude protein have the protein hydrolysates of fish waste and sunflower meal, taken in a ratio of 1 to 2. Accordingly, in this case, a high content of dry matter was noted 65.57 ± 0.18%), crude protein 41.92±0.72%, crude fat 2.74±0.12% and low crude fiber 14.34±0.10%, and the apparent protein digestibility coefficient was 78.8%. The compiled enzyme compositions for enzymatic hydrolysis are optimal at a temperature of 50°C and the proportion of the enzyme composition for fermentation in an amount of 5%, containing enzyme preparations: Protozyme - 40%, Cellulase - 35%, Lipase - 10% and Amylorizin - 15%.
Peculiarities of clinical and laboratory manifestations of hepatopathy: The path to medical consensus
Authors: Ponamarev Vladimir , Popova Olga
Published: February 2024

The article analyzes the information available in the scientific literature on the clinical and laboratory manifestations of liver pathologies of various origins, mainly in productive animals, in order to achieve a medical consensus on the most relevant methods for diagnosing such pathologies. Hepatopathy is a universal term to refer to various liver diseases. The incidence of hepatosis in cattle can reach up to 50%, in swine up to 90%, and in canines up to 68%. At the moment, a large amount of material on this topic has been accumulated for each animal species separately. The goal is to systematize the available material on all types of animals to identify the characteristics of the clinical and laboratory manifestations of hepatopathy in animals with different types of nutrition. For pigs, a more characteristic type of hepatopathy is hepatodystrophy of toxic etiology, with vacuolar degeneration and necrosis of hepatocytes. For cows, especially highly productive ones, a more common type of hepatopathy is fatty liver degeneration. For dogs, a more characteristic type of hepatopathy is acute hepatitis, which occurs in response to infectious and non-infectious diseases. The study established that, despite various etiological factors and species predispositions to them, hepatopathy in different animal species manifests itself in the same way. It is not clinically expressed but has a significant effect on reproductive function; laboratory: three syndromes: cytolysis, hepatodepression, and cholestasis.
Application of quantum technology Variational Quantum Classifier in agriculture for classification of wheat varieties
Authors: Mukhamedieva D.T. , Sobirov R.A.
Published: February 2024

This study proposes the use of Variational Quantum Classifier for automated classification of wheat varieties. A model trained on a large data set will be able to identify unique patterns and relationships between seed characteristics and cultivar membership. This will allow farmers and researchers to more accurately identify wheat varieties, which in turn can improve growing and crop management processes. This approach is justified not only by the need to optimize agricultural production, but also in the context of the use of advanced technologies to achieve precision and efficiency in the agricultural sector. As a result of this research, it is expected that the quality and sustainability of wheat production will improve, which is important for food security and sustainable agricultural development. The goal of the problem is to classify wheat varieties based on seed characteristics. VQC is trained on the training dataset and then evaluated on the test dataset. To evaluate the performance of the model, various metrics are used, such as accuracy, precision, recall, F1-score and Confusion Matrix.
Optimization of the current spray angle of the nozzles of the adaptive distribution system of a single-support boom sprayer
Authors: Dembovskiy Ilya , Rodimtsev Sergey
Published: February 2024

One of the unsolved problems of plant protection mechanization is the uneven distribution of pesticides due to vertical vibrations of the sprayer boom. At the same time, the variation of the treatment band with each sprayer can reach 38% or more. This issue is even more relevant for single-support wheelbarrow sprayers, which are used in breeding and primary seed production. This significantly affects the quality of the technological operation. A technical solution to this problem could be the use of sprayers with variable spray geometry. Such a solution requires an analytical substantiation of the dependence of the spray pattern angle on the position angle of the sprayer boom. The purpose of the proposed research is to develop a technique for optimizing the spray angle of sprayer nozzles, taking into account the vertical vibrations of the distribution rod. Geometric and mathematical modeling, theoretical analysis of qualitative and agrotechnical parameters of spraying, substantiation of the laws of the technological process of spraying based on the known laws of physics and classical mathematics, as well as a method of nomogramming functions of several variables were used as scientific methods. It has been established that the uniformity of the application of protective equipment is determined not only by the position of the rod in the vertical plane, but also by the value of the root spray angle, the height of the installation of the sprayer and its position relative to the center of oscillation of the rod. An analytical expression is derived that relates the current width of the processing strip from one sprayer to the specified factors. The dependence of the optimal spray angle on the angle of inclination of the sprayer boom is also proposed. A nomogram has been developed that takes into account permissible deviations in the uneven distribution of the working fluid during spraying. The optimization technique is new. It is applicable to the development of software for the sprayer control complex, which is equipped with an adaptive pesticide distribution system in changing conditions.
Why Craniofacial Surgeons/Researchers Need to be Aware of Native American Myopathy?
Authors: Almomen Momen , Burgon Patrick G.
Published: February 2024

Congenital myopathy type 13 (CMYO13), also known as Native American myopathy, is a rare muscle disease characterized by early-onset hypotonia, muscle weakness, delayed motor milestones, and susceptibility to malignant hyperthermia. The phenotypic spectrum of congenital myopathy type 13 is expanding, with milder forms reported in non-native American patients. The first description of the disease dates to 1987 when Bailey and Bloch described an infant belonging to a Native American tribe with cleft palate, micrognathia, arthrogryposis, and general-anesthesia-induced malignant hyperthermia reaction; the cause of the latter remains poorly defined in this rare disease. The pan-ethnic distribution, as well as its predisposition to malignant hyperthermia, makes the identification of CMYO13 essential to avoid life-threatening, anesthesia-related complications. In this article, we are going to review the clinical phenotype of this disease and the pathophysiology of this rare disease with a focus on two unique features of the disease, namely cleft palate and malignant hyperthermia. We also highlight the importance of recognizing this disease's expanding phenotypic spectrum—including its susceptibility to malignant hyperthermia—and providing appropriate care to affected individuals and families.
Prevalence and predictive factors of colorectal sessile serrated lesions in younger individuals
Authors: Yeh Jen-Hao , Lin Chih-Wen , Hsiao Po-Jen , Perng Daw-Shyong , Chen Jen-Chieh , Hung Kuo-Tung , Hsu Chia-Chang , Chen Chia-Chi , Liu Yu-Peng , Lee Yi-Chia , Wang Jaw-Yuan
Published: February 2024

Background Sessile serrated lesions (SSLs) are obscured lesions predominantly in the right-sided colon and associated with interval colorectal cancer; however, their prevalence and risk factors among younger individuals remain unclear.

Methods This retrospective study enrolled individuals who underwent index colonoscopy. The primary outcome was the SSL prevalence in the younger (<50 years) and older (≥50 years) age groups, while the secondary outcomes included clinically significant serrated polyps (CSSPs). Multivariable logistic regression was employed to identify predictors.

Results Of the 9854 eligible individuals, 4712 (47.8%) were categorized into the younger age group. Individuals in the younger age group exhibited lower prevalences of adenomas (22.6% vs. 46.2%; P<0.001) and right-sided adenomas (11.2% vs. 27.2%; P<0.001) compared with their older counterparts. However, both groups exhibited a similar prevalence of SSLs (7.2% vs. 6.5%; P=0.16) and CSSPs (10.3% vs. 10.3%;P=0.96). Multivariable analysis revealed that age 40–49 years (odds ratio [OR] 1.81, 95%CI 1.01–3.23), longer withdrawal time (OR 1.17, 95%CI 1.14–1.20, per minute increment), and endoscopist performance (OR 3.35, 95%CI 2.44–4.58) were independent predictors of SSL detection in the younger age group. No significant correlation was observed between adenoma and SSL detection rates among endoscopists.

Conclusion SSLs are not uncommon among younger individuals. Moreover, diligent effort and expertise are of paramount importance in SSL detection. Future studies should explore the clinical significance of SSLs in individuals of younger age.
Fragments Synthesis of A. baumannii ATCC 17961 O-Antigen
Authors: Wang Liming , Zhang Qingju , Li Xinxin , Duan Liangshen , Liu Deyong , Qi Jianying
Published: February 2024

Acinetobacter baumannii can cause many diseases including septicemia, pneumonia, meningitis, soft tissue, and urinary tract infections. Herein, we described the synthesis of one trisaccharide and two tetrasaccharide fragments derived from A. baumannii ATCC 17961 O-antigen that can be used for screening novel glyco-epitopes and for developing a synthetic carbohydrate-based vaccine against A. baumannii infection. The overall yields for the synthesis of the desired trisaccharide 1, tetrasaccharide 2, and tetrasaccharide 3 are 26.8% (8 steps), 21.6% (9 steps), and 24.5% (6 steps), respectively.
Sleep Quality in Individuals with and without Persistent Postpartum Hypertension
Authors: Wang Tiffany L. , Bryan Samantha G. , Jeyabalan Arundhathi , Facco Francesca L. , Gandley Robin E. , Hubel Carl A. , Catov Janet M. , Hauspurg Alisse K.
Published: February 2024

Objective This study aimed to compare sleep quality at 1 year postpartum following a hypertensive disorder of pregnancy (HDP) among individuals with persistent postpartum hypertension (HTN) compared with those with normal blood pressures (BPs).

Study Design We combined data from the Heart Health 4 New Moms pilot randomized trial (n = 118) and the Pathways prospective cohort study (n = 36). Individuals with a singleton pregnancy complicated by gestational HTN or preeclampsia underwent a research study visit at a mean 48.7 ± 9.5 weeks postpartum with standardized BP measurement and assessment of subjective sleep quality with the Pittsburgh Sleep Quality Index (PSQI). Persistent postpartum HTN was defined as Stage 1 HTN or greater (mean systolic BP ≥ 130 mm Hg or mean diastolic BP ≥ 80 mm Hg over three measurements at rest) or requiring antihypertensive medication. Statistical analysis was performed using univariate and multivariable logistic regression analyses.

Results Of 154 individuals with an HDP included in the analysis, 84 (55%) were normotensive at 1 year postpartum and 70 (45%) had persistent postpartum HTN. Individuals with persistent postpartum HTN were more likely to be older, self-identify as Black race, have higher prepregnancy and 1-year postpartum body mass index (BMI), be multiparous, and deliver at an earlier gestational age. The mean global PSQI score was 8.7 ± 3.7, with 81% reporting poor sleep (PSQI > 5), and scores were higher among individuals who were persistently hypertensive (9.6 ± 3.5) compared with those who were normotensive at 1 year postpartum (7.9 ± 3.6), p < 0.01. Findings were unchanged in a multivariable model adjusting for age, self-reported race, prepregnancy BMI, and parity.

Conclusion Following an HDP, individuals reported poor sleep quality at 1 year postpartum. Individuals with persistent postpartum HTN reported lower sleep quality, suggesting that sleep behavior may be a target for intervention to improve maternal cardiovascular health following an HDP.

Key Points
On the classification of degenerate equilibrium states of multisublattice SU(4) magnets with spin s = 3/2
Authors: Kovalevsky M. Yu.
Published: February 2024

The equilibrium states of multisublattice magnets with spin s = 3/2 are studied. The developed approach essentially uses the symmetry properties of the Hamiltonian, the idea of the residual symmetry of the equilibrium state, and the form of order parameters. On this basis, without using any model assumptions, classification equations for order parameters are obtained. Solutions of these equations are given in cases of broken SU(3) and SU(4) symmetries. The equilibrium structure of order parameters is presented in terms of the spontaneous anisotropy parameters of the residual symmetry generator.
Variable-temperature lightwave-driven scanning tunneling microscope with a compact, turn-key terahertz source
Authors: Azazoglu Hüseyin , Kapitza Philip , Mittendorff Martin , Möller Rolf , Gruber Manuel
Published: February 2024

We report on a lightwave-driven scanning tunneling microscope based on a home-built microscope and a compact, commercial, and cost-effective terahertz-generation unit with a repetition rate of 100 MHz. The measurements are performed in an ultrahigh vacuum at temperatures between 8.5 and 300 K. The cross-correlation of the pump and probe pulses indicates a temporal resolution on the order of a picosecond. In terms of spatial resolution, CO molecules, step edges, and atomically resolved terraces are readily observed in terahertz images, with sometimes better contrast than in the topographic and (DC) current channels. The utilization of a compact, turn-key terahertz-generation system requires only limited experience with optics and terahertz generation, which may facilitate the deployment of the technique to further research groups.
de Broglie–Bohm analysis of a nonlinear membrane: From quantum to classical chaos
Authors: Santos Lima Henrique , Paixão Matheus M. A. , Tsallis Constantino
Published: February 2024

Within the de Broglie–Bohm theory, we numerically study a generic two-dimensional anharmonic oscillator including cubic and quartic interactions in addition to a bilinear coupling term. Our analysis of the quantum velocity fields and trajectories reveals the emergence of dynamical vortices. In their vicinity, fingerprints of chaotic behavior such as unpredictability and sensitivity to initial conditions are detected. The simultaneous presence of the off-diagonal −kxy and nonlinear terms leads to robust quantum chaos very analogous to its classical version.
Transition to anomalous dynamics in a simple random map
Authors: Yan Jin , Majumdar Moitrish , Ruffo Stefano , Sato Yuzuru , Beck Christian , Klages Rainer
Published: February 2024

The famous doubling map (or dyadic transformation) is perhaps the simplest deterministic dynamical system exhibiting chaotic dynamics. It is a piecewise linear time-discrete map on the unit interval with a uniform slope larger than one, hence expanding, with a positive Lyapunov exponent and a uniform invariant density. If the slope is less than one, the map becomes contracting, the Lyapunov exponent is negative, and the density trivially collapses onto a fixed point. Sampling from these two different types of maps at each time step by randomly selecting the expanding one with probability p, and the contracting one with probability 1−p, gives a prototype of a random dynamical system. Here, we calculate the invariant density of this simple random map, as well as its position autocorrelation function, analytically and numerically under variation of p. We find that the map exhibits a non-trivial transition from fully chaotic to completely regular dynamics by generating a long-time anomalous dynamics at a critical sampling probability pc, defined by a zero Lyapunov exponent. This anomalous dynamics is characterized by an infinite invariant density, weak ergodicity breaking, and power-law correlation decay.
Extending the propagation length of graphene plasmons via nonlinear frequency conversion
Authors: Landa Eli , Leiderman Liam , Mazor Yarden , Epstein Itai
Published: February 2024

Graphene plasmons (GPs) are broadband and electrically tunable mid-infrared (MIR)/terahertz (THz) excitations, exhibiting high confinement factors exceeding two orders of magnitude. Such highly confined modes are extremely attractive for nonlinear frequency conversion owing to the large inherent field enhancement. However, this high confinement is also accompanied by losses, and together with the centrosymmetric nature of graphene practical usage of its properties in second-order nonlinear processes remains hindered. In this paper, we introduce an approach for realizing quasi-phase-matching (QPM) of propagating GPs, by placing the graphene on an orientationally patterned GaAs substrate—a transparent material in the MIR/THz range with a large second-order nonlinear coefficient. We analyze the complete frequency/Fermi-level space for QPMed second-harmonic generation of GPs in the MIR and THz and demonstrate GP amplification and loss compensation. We find that our approach provides extended GP propagation lengths that are more than twice larger than the state-of-the-art cryogenic temperature propagation lengths. The approach is general to all second-order nonlinear processes, such as sum and difference frequency generation, thus opening a path for efficient and electrically tunable QPM nonlinear processes at the atomic scale.
Learning transfer operators by kernel density estimation
Authors: Surasinghe Sudam , Fish Jeremie , Bollt Erik M.
Published: February 2024

Inference of transfer operators from data is often formulated as a classical problem that hinges on the Ulam method. The conventional description, known as the Ulam–Galerkin method, involves projecting onto basis functions represented as characteristic functions supported over a fine grid of rectangles. From this perspective, the Ulam–Galerkin approach can be interpreted as density estimation using the histogram method. In this study, we recast the problem within the framework of statistical density estimation. This alternative perspective allows for an explicit and rigorous analysis of bias and variance, thereby facilitating a discussion on the mean square error. Through comprehensive examples utilizing the logistic map and a Markov map, we demonstrate the validity and effectiveness of this approach in estimating the eigenvectors of the Frobenius–Perron operator. We compare the performance of histogram density estimation (HDE) and kernel density estimation (KDE) methods and find that KDE generally outperforms HDE in terms of accuracy. However, it is important to note that KDE exhibits limitations around boundary points and jumps. Based on our research findings, we suggest the possibility of incorporating other density estimation methods into this field and propose future investigations into the application of KDE-based estimation for high-dimensional maps. These findings provide valuable insights for researchers and practitioners working on estimating the Frobenius–Perron operator and highlight the potential of density estimation techniques in this area of study.
Rheology-based wall function approach for wall-bounded turbulent flows of Herschel–Bulkley fluids
Authors: Yusufi B. K. , Kapelan Z. , Mehta D.
Published: February 2024

Modeling fully developed turbulent flow for Herschel–Bulkley (HB) fluids in pipes is a long-standing challenge. Existing semi-empirical, theoretical, and numerical methods are either inconsistent with experimental data or are validated for low Reynolds numbers. This study focuses on validating a novel approach using rheology-based wall functions within Reynolds-averaged Navier–Stokes solvers. Simulations of wall shear stress and velocity profiles were conducted across a wide range of Reynolds numbers using a single-phase HB fluid, with measurements taken both upstream and downstream of a 90° pipe bend. Two turbulence closure models, the k–ε model and the Reynolds stress model, were employed with the wall function implemented as a specified shear boundary condition. Results demonstrate significant improvements over the Newtonian-based models, such as standard wall function by Launder–Spalding or with available semi-empirical models, achieving strong statistical correlations and minimal deviation (from the experimental findings) at high Reynolds numbers. The study also examines the utility of the wall viscosity Reynolds number and assesses the reliability of semi-empirical models for HB fluids. These findings offer valuable insights for enhancing modeling accuracy in complex fluid flow scenarios, with potential applications spanning industries like mining, chemical processing, petroleum transportation, and sanitation systems, providing practical alternatives to costly experimental procedures in pipe systems.
Characterization of a spring pendulum phase-space trajectories
Authors: Acosta-Zamora Karla P. , Núñez González José , González Ahtziri , Ramos Eduardo
Published: February 2024

We study the geometrical properties of phase-space trajectories (or orbits) of a spring pendulum as functions of the energy. Poincaré maps are used to describe the properties of the system. The points in the Poincaré maps of regular orbits (non-chaotic) cluster around separated segments or in chains of islands. Looking at how segments are formed, we conclude that the orbits are closely related to torus knots. Examining the toroidal and poloidal turns of the orbits, we introduce the definition of a rational parameter Ω, which is closely related to the concept of frequency used in the analysis of dynamical systems. Algorithms were developed to calculate Ω, and we found that this parameter naturally describes the orbits in terms of Farey sequences; also, calculations show that orbits with the same Ω have similar dynamics. Orbits corresponding to chains of islands are identified with cable knots that can be characterized using two parameters analogous to Ω. In some cases, non-trivial cable knots were found. With the analysis presented in this study, it is shown that Ω follows predictable distributions in the (z,Ω) space.
Acoustoelastic characterization of plates using zero group velocity Lamb modes
Authors: Morales Rosa E. , Pathak Niket , Lum Jordan S. , Kube Christopher M. , Murray Todd W. , Stobbe David M.
Published: February 2024

Acoustoelasticity, a characteristic of material anharmonicity, gives rise to a link between wave propagation velocity and the stress state in materials. Ultrasonic techniques to monitor this coupling, particularly with high sensitivity and in a noncontact manner, can have widespread application both in the quantification of applied and residual stress and in the characterization of nonlinear material behavior through measurement of higher order elastic constants. Here, we use a laser ultrasonic technique to excite and detect zero group velocity (ZGV) Lamb wave resonances in aluminum plates under uniaxial loading. A laser line source is used to excite these resonances at different orientations with respect to the applied load, and the signals are detected using an interferometer. The effects of stress and source orientation on ZGV resonance frequencies are validated using the theory of acoustoelastic Lamb wave propagation. In addition, a model-based inversion technique is used to extract Murnaghan's third-order elastic constants from measurements of the stress dependence of the first two ZGV modes generated parallel and perpendicular to the applied load. Laser generation and detection of ZGV resonances is shown to be an effective and powerful approach for the noncontact and nondestructive acoustoelastic characterization of elastic waveguides.
Data-driven turbulence modeling for fluid flow and heat transfer in peripheral subchannels of a rod bundle
Authors: Li H. , Yakovenko S. , Ivashchenko V. , Lukyanov A. , Mullyadzhanov R. , Tokarev M.
Published: February 2024

This study presents a comparison of the performance of machine learning (ML) techniques, specifically multi-dimensional gene expression programming (MGEP), tensor basis neural network (TBNN), and also proposes a novel universally interpretable machine learning architecture to model the turbulent scalar flux (UIML-s) to enhance turbulence models for fluid flows at different Prandtl numbers in channels with complex shapes of walls in the channel cross section. In particular, peripheral subchannels of rod bundles are of primary interest. However, the accuracy of mean velocity and scalar distributions predicted by commonly used turbulence models still poses a challenge compared to data extracted from high-fidelity eddy-resolving numerical simulations, particularly for engineering applications involving complex geometry flows. In the present study, by utilizing an explicit algebraic expression for the nonlinear Reynolds-stress term obtained through both the evolutionary MGEP optimization and TBNN, the secondary flow structure has been adequately predicted in the cross-wise mean velocity distributions in the square duct and the rectangular channel with three longitudinal rods. This structure is also observed in the data from the concurrent runs performed by direct numerical simulation (DNS) but is completely absent in the results produced by a baseline Reynolds-averaged Navier–Stokes (RANS) closure, which employs the linear eddy viscosity model for the Reynolds stress tensor. Comparison of MGEP and TBNN has shown their nearly equal performance in a square duct flow; however, MGEP works better for the more complex geometry channel with three rods. Furthermore, based on the velocity field produced by the RANS-MGEP model, the ML modification of the gradient diffusion hypothesis, integrated into the aforementioned novel RANS-ML model called as UIML-s, significantly improves the mean scalar distributions in a flow with three bumps serving as a prototype for the peripheral subchannel of rod bundle. The normalized root mean squared error decreases from 13.5% to 7.6%, bringing the predicted distributions closer to the DNS data, particularly in the near-wall region. Another approach, MGEP-s, also yields the acceptable results, which are nearly identical to those from UIML-s. These findings highlight the potential of using data-driven calibration of turbulence models with nonlinear closures to enhance the predictability for RANS simulations of fluid flows, heat, and mass transfer in channels with complex geometry.
Field-programmable gate array-based residual amplitude modulation suppression and control for compact atomic clocks
Authors: Nguyen Tin Nghia , Schibli Thomas R.
Published: February 2024

We designed a field-programmable gate array (FPGA) fabric to provide phase modulation techniques to lock lasers to optical frequency references. The method incorporates an active residual amplitude modulation (RAM) suppression scheme that relies on complex modulation. All the required servos to construct an optical atomic clock are incorporated into the same low-cost, commercial FPGA chip. We demonstrate a reliable, long-term RAM suppression of 60 dB with the remaining RAM level at −100 dBc and an improved stability of three decades when applied on a two-photon rubidium clock.
Investigation on a high-power V-band transit-time oscillator under a low guiding magnetic field with a focusing cathode
Authors: Chen Zulong , Wang Lei , Ling Junpu , Song Lili , He Juntao
Published: February 2024

Low guiding magnetic fields are favored for high-power microwave sources in practical applications for the sake of compactness and miniaturization, especially for permanent magnet packaging to replace the bulky and heavy solenoid system. A novel focusing cathode is proposed in a V-band transit-time oscillator to reduce the requirement for guiding magnetic fields. Particle-in-cell simulation results indicate that in the diode region, the radial electric field and electron beam current are reduced with the focusing cathode, further leading to improved transmission of the electron beam under a low guiding magnetic field. With an input of diode voltage of 393 kV, a beam current of 5.25 kA, and a low guiding magnetic field of 0.6 T, the transit-time oscillator outputs a microwave with an average power of 566 MW and a frequency of 58.6 GHz, resulting in a conversion efficiency of 27.3%. The proposed V-band transit-time oscillator with a focusing cathode can also stably work under a large range of input voltage and magnetic field, desired for further research with permanent magnet packaging.
Characterization of droplet impact dynamics onto a stationary solid torus
Authors: Sahoo Prakasha Chandra , Senapati Jnana Ranjan , Rana Basanta Kumar
Published: February 2024

The impingement mechanism of a liquid droplet on a solid torus surface is demonstrated using numerical simulations and an analytical approach. A computational model employing the volume of fluid method is developed to conduct simulations for the present investigation. Several influencing parameters, namely, diameter ratio (Dt/Do), contact angle (θ), initial droplet velocity (described by Weber number, We), surface tension (specified by Bond number, Bo), and viscosity of liquid drop (described by Ohnesorge number, Oh) are employed to characterize the impacting dynamics of a water drop onto a stationary toroidal substrate. The pattern of temporal and maximum deformation factors is elaborated by considering various relevant influencing factors to describe the fluidic behavior of the drop impingement mechanism. The key findings indicate that the developed central film gets ruptured at the early stage when the value of Dt/Do is lower because a relatively thin film is developed. Concomitantly, the very tiny drops get pinched off at Dt/Do= 0.83, whereas the detached drops are relatively large-sized in the case of lower Dt/Do= 0.16 due to the higher drainage rate of liquid mass through the hole at lower Dt/Do. It is also revealed that the first pinch-off is found to be faster with the continual upsurge of We for a specific value of Dt/Do and θ. Aside from that, efforts are made to show a scattered regime map in order to differentiate the pattern of droplet configuration during impingement. We have also attempted to establish a correlation that effectively characterizes the maximum deformation factor, which closely matches with the numerical findings. The developed correlation exhibits a firm agreement with the numerical data within deviations of 8.5%. Finally, an analytical framework is formulated to predict the deformations factor, which closely agrees with the computational findings.
Mixing dynamics in the synthesis of nanoparticle-stabilized water-in-water emulsion: Impact on size and stability
Authors: Shekhar Chandra , Pawak Vishal Singh , Mehandia Vishwajeet , Ramamirtham Sashikumar , Kullappan Monicka , Sabapathy Manigandan
Published: February 2024

This communication presents a comprehensive investigation into the impact of mixing on the synthesis of water-in-water Pickering emulsions. The approach employs commercial-grade oppositely charged nanoparticles within two distinct fluid phases, facilitating self-assembly and the formation of aggregates with variable sizes and compositions. Enhanced interfacial area, achieved through aggregate adsorption at the interface, elevates the Gibbs detachment energy of particles between the two aqueous phases, leading to stable emulsion formation. We further explore the effect of various mixing devices, including high-pressure and sonic wave mixing. Our findings reveal that mixing within the aqueous phase critically influences emulsion size, with sonicator-assisted mixing producing smaller droplets than homogenizer mixing. Both devices yield poly-dispersed droplet size distributions. Interestingly, the droplet size correlates well with the Hinze scale (hd), and the Kolmogorov length scale (ld) exhibits good correspondence within a specific operating range. The proposed method introduces a streamlined, one-step synthesis process for easy preparation, demonstrating excellent stability for a minimum of 30 days. This study pioneers the investigation of mixing effects within an aqueous two-phase system utilizing a Pickering emulsion template.
Local dynamic responses of magnetic reconnection to three-dimensional perturbations in a laboratory plasma
Authors: Xie Jinlin , Shi Peiyun , Ji Hantao , Jara-Almonte Jonathan , Yoo Jongsoo , Okunishi Yukehi , Dorfman Seth , Yamada Masaaki
Published: February 2024

The dynamic responses of magnetic reconnection to localized three-dimensional (3D) magnetic field perturbations imposed by a pair of figure-8-shaped coils are investigated in the Magnetic Reconnection Experiment (MRX) device. Both the magnetic field geometry and current sheet profiles are altered by external perturbations. For the case when the inductive electric field associated with these perturbations aligns with the preexisting reconnection electric field, O-type magnetic structures appear within an elongated current sheet. When these magnetic structures are ejected downstream at the speed close to the ion outflow velocity, the inductive electric field is enhanced considerably. Despite that the imposed perturbation amplitude is larger than 30% of the original reconnecting magnetic field, the overall reconnection process remains robust without current sheet disruptions. This technique to form O-type magnetic structures can serve as an additional experimental knob for future systematic laboratory investigations of 3D magnetic reconnection and related instabilities without disrupting two-dimensional current sheet.
Particle-resolved simulations and measurements of the flow through a uniform packed bed
Authors: Sadowski Wojciech , Sayyari Mohammed , di Mare Francesca , Velten Christin , Zähringer Katharina
Published: February 2024

The present study focuses on the assessment of the performance of a finite volume method based, particle-resolved simulation approach to predict the flow through a model packed-bed consisting of 21 layers of spheres arranged in the body centered cubic packing. The unsteady flow developing in the freeboard is also considered. Two highly resolved large eddy simulation were preformed, for two Reynolds numbers, 300 and 500, based on the particle diameter, employing a polyhedral, boundary-conforming mesh. The geometry and the flow conditions are set to reproduce the flow conditions investigated in the experiment carried out by Velten and Zähringer [“Flow field characterisation of gaseous flow in a packed bed by particle image velocimetry,” Transp. Porous Media 150, 307 (2023)] using particle image velocimetry. The numerical results compare favorably with the measurements both inside and above the bed. The effect of differences arising between the physical and numerical configurations is thoroughly discussed alongside the impact of meshing strategy on the accuracy of the predictions.
Synchronization enhancement subjected to adaptive blinking coupling
Authors: Irankhah Reza , Mehrabbeik Mahtab , Parastesh Fatemeh , Rajagopal Karthikeyan , Jafari Sajad , Kurths Jürgen
Published: February 2024

Synchronization holds a significant role, notably within chaotic systems, in various contexts where the coordinated behavior of systems plays a pivotal and indispensable role. Hence, many studies have been dedicated to investigating the underlying mechanism of synchronization of chaotic systems. Networks with time-varying coupling, particularly those with blinking coupling, have been proven essential. The reason is that such coupling schemes introduce dynamic variations that enhance adaptability and robustness, making them applicable in various real-world scenarios. This paper introduces a novel adaptive blinking coupling, wherein the coupling adapts dynamically based on the most influential variable exhibiting the most significant average disparity. To ensure an equitable selection of the most effective coupling at each time instance, the average difference of each variable is normalized to the synchronous solution’s range. Due to this adaptive coupling selection, synchronization enhancement is expected to be observed. This hypothesis is assessed within networks of identical systems, encompassing Lorenz, Rössler, Chen, Hindmarsh–Rose, forced Duffing, and forced van der Pol systems. The results demonstrated a substantial improvement in synchronization when employing adaptive blinking coupling, particularly when applying the normalization process.
Physics-informed neural network for solving Young–Laplace equation and identifying parameters
Authors: Pan Cunliang , Feng Shi , Tao Shengyang , Zhang Hongwu , Zheng Yonggang , Ye Hongfei
Published: February 2024

Capillarity is prevalent in nature, daily life, and industrial processes, governed by the fundamental Young–Laplace equation. Solving this equation not only deepens our understanding of natural phenomena but also yields insight into industrial advancements. To tackle the challenges posed by traditional numerical methods in parameter identification and complex boundary condition handling, the Young–Laplace physics-informed neural network (Y–L PINN) is established to solve the Young–Laplace equation within tubular domain. The computations on the classical capillary rise scenario confirm the accuracy of the proposed method on the basis of the comparison with Jurin's law, experimental data, and numerical results. Furthermore, the Y–L PINN method excels in parameter identification, e.g., contact angle, Bond number, and so on. These numerical examples even demonstrate its excellent predictive ability from the noisy data. For the complex boundary, it is rather convenient to obtain the liquid meniscus shapes in vessels, which is in good agreement with the experimental results. We further examine the variation of meniscus profile with wetting condition or discontinuous boundary. Importantly, the Y–L PINN method could directly solve the Young–Laplace equation with discontinuous wetting boundary without additional techniques. This work provides valuable insight for material wettability assessments, microstructure preparation, and microfluidics research.
Fourier-transform spectroscopy and global deperturbation treatment of the A1Σu+ and b3Πu states of K2 in the entire bound energy range
Authors: Klincare I. , Lapins A. , Tamanis M. , Ferber R. , Zaitsevskii A. , Pazyuk E. A. , Stolyarov A. V.
Published: February 2024

Rotationally resolved Fourier-transform spectra of laser-induced fluorescence A1Σu+∼b3Πu→X1Σg+ of K2 molecules were recorded and analyzed, yielding 4053 term values of the spin–orbit (SO) coupled A ∼ b complex of the 39K2 isotopologue with ∼0.01 cm−1 accuracy. Their compilation with 1739 term values from previously published sources allowed them to cover the energy range [9955, 17 436] cm−1 from the bottom of the lower-lying b3Πu state up to the vicinity of the atomic asymptote 4s2S12 + 4p2P12, with a rotational quantum number J ∈ [0, 149]. The experimental data were processed by a direct 6 × 6 coupled-channel (CC) deperturbation treatment, which accounted explicitly for both SO and electronic-rotational interactions between all six e-symmetry states: A1Σu+(0u+), b3Πu(0u+,1u,2u), c3Σu(1u), and B1Πu(1u). The initial parameters of the global deperturbation model have been estimated in the framework of ab initio electronic structure calculations applying multi-reference configuration-interaction and coupled-clusters methods. The interatomic potentials analytically defined for A and b states, as well as SO-splitting of the triplet b state and A ∼ b SO-coupling functions, have been particularly refined to fit the 5792 term values of the 39K2 isotopologue, whereas the rest parameters were fixed on their ab initio values. The resulting mass-invariant parameters of the 6 × 6 CC model reproduced the overall rovibronic term energies of the A ∼ b complex of 39K2 with accuracy, which is well within the experimental errors. The quality of the deperturbation analysis was independently confirmed by comparison with the present obtained 705 and 14 term values of respective 39K41K and 41K2 isotopologues, as well as by agreement between measured and predicted relative intensity distributions in long A ∼ b → X(vX) band progressions. This deperturbation analysis provided the refined dissociation energy Tdis = 17 474.569(5) cm−1 and the long-range coefficient C3Σ = 5.501(4) × 105 cm−1 Å3 relevant to the non-relativistic atomic limit 4s + 4p. The derived Tdis yielded the accurate well depth De = 4450.910(5) cm−1 for the ground X1Σg+ state, whereas the new C3Σ value yielded the improved estimates for atomic K(4p2P12;32) radiative lifetimes, τ12 = 26.67(3) and τ32 = 26.32(3) ns.
Symmetry of spin–orbit torque induced meron annihilation
Authors: Jiang Siyuan , Gao Nan
Published: February 2024

Electrical manipulation of the topological charges of magnetic vortices is of vital importance for the development of vortex-based devices. Here, we show that the spin–orbit torque (SOT) effect can be employed to deterministically and selectively annihilate the vortex core, and this process exhibits a symmetry that is consistent with that of the SOT-induced magnetization switching in perpendicularly magnetized systems. By changing the SOT current pulse direction, it is also possible to write back a vortex with random topological charges from the quasi-single-domain state after annihilation. These intriguing results can be utilized as a random topological charge generator and applied in stochastic computing where a tunable random stream source plays a central role.
Growth mechanism of Mn-doped diamond (111) layers in microwave plasma chemical vapor deposition
Authors: Kawano Makoto , Hirama Kazuyuki , Taniyasu Yoshitaka , Kumakura Kazuhide
Published: February 2024

Mn-doped diamond (111) layers were grown by microwave plasma chemical vapor deposition using bis(methylcyclopentadienyl)manganese as a Mn source. The Mn concentration ([Mn]) was intentionally controlled in the range between ∼1 × 1015 and ∼1 × 1017 cm−3 by regulating the Mn/C molar ratio in the gas phase within 0.15%–3.0%. When [Mn] > ∼1 × 1016 cm−3, the step edges of the growing surface changed from straight to a zigzag shape. Using a model based on the classic theory by Cabrera and Vermilyea, we show that this roughening of the step edges resulted from step pinning due to Mn atoms absorbed on the diamond surfaces.
Solution of electromagnetic scattering field of adjacent transmission towers based on reciprocity theorem
Authors: Tang B. , Zhang L. B. , Shang Z. Y. , Wang F.
Published: February 2024

Due to the large number of transmission towers being built, the dense distribution of transmission towers is inevitable in some areas. Densely distributed transmission towers will generate severe electromagnetic coupling, which will affect the setting of the passive interference protection distance between transmission towers and adjacent radio stations. Therefore, based on the traditional algorithm for solving the electromagnetic scattering field of a single electrically large target in wide area space, the electromagnetic coupling effect between multiple adjacent transmission towers within a range of 10 times the signal wavelength was considered. Based on the reciprocity relationship between the scattering electric field and the source and the introduced auxiliary field source as the intermediate variable, the electric field integral equation of the secondary scattering field generated by the electromagnetic coupling effect of adjacent transmission towers was derived, and the secondary scattering field is superimposed with the primary scattering field of the transmission generated by the electromagnetic wave excitation of the radio station, obtaining the electromagnetic scattering field at any point. In order to verify the accuracy of the algorithm proposed in this article, the scaled model experiments for the electromagnetic coupling effect between two transmission towers in an anechoic chamber were conducted. The average error of the algorithm proposed in this article is 6.73%, while the error of traditional algorithms is 20.18%. Compared with the traditional algorithm, the accuracy of the proposed algorithm is improved by 13.45%.
Oscillatory dynamics of discrete reaction-zones for hydrogen–oxygen diffusion flames within a narrow channel
Authors: Kang Xin
Published: February 2024

A diffusion flame in the fuel-oxidizer mixing layer within a narrow channel can be split into several stationary, discrete flame segments at some particular conditions. This unique flame structure has deeply been analyzed in previous literature. In this paper, by performing numerical simulations using a transient, low-Mach number, reacting flow solver in OpenFOAM, unsteady dynamics of separated reaction zones for low Lewis number, hydrogen–oxygen diffusion flames in a 30 × 5 × 0.75 mm3 microchannel are newly discovered. For a variety of inflow rates (H2/O2 flow rate of 300/150, 200/100, and 100/50  sccm) and wall temperatures (Tw = 900, 800, 700, 600, and 500 K) investigated, stable and continuous flame sheets can only be witnessed at large Reynolds numbers or high wall temperatures. Flames at other conditions are found in a discrete form, presenting an unstable and repetitive feature. Specifically, in the wake of the leading, anchored diffusion flame, edge flames with tribrachial structures are consecutively established and then propagate downstream, while eventually end by moving out of the channel, or being extinguished halfway, or behaving in a mixed mode (the two events occur alternately for two successively generated edge flames). Effects of Lewis numbers on flame behaviors are also studied via helium addition to both the fuel and oxidizer stream. Isolated reaction zones at a steady state can be witnessed for a relatively large Lewis number under a high level of addition.
Medium-range structural order in amorphous Ge2Sb2Te5 phase change material
Authors: Gong Qingmei , Peterlechner Martin , Jiang Haihong , Rösner Harald , Wilde Gerhard
Published: February 2024

The crystallization rate is an important factor for the application of phase change materials as memory devices, which, thus, motivates a strong interest in the underlying crystallization processes. We analyzed the crystallization kinetics of as-deposited amorphous Ge2Sb2Te5 by differential scanning calorimetry, revealing that the thermal treatment below the crystallization onset temperature effectively enhances the crystallization rate compared to the as-deposited samples. Variable resolution fluctuation electron microscopy was carried out to characterize the corresponding amorphous structure of the as-deposited films and the differently annealed states regarding their medium-range order (MRO). As a result, relatively large MRO correlation lengths in the range of 3–4 nm were observed, whereas the MRO volume fraction doubled after longer annealing treatments, demonstrating the importance of MRO and MRO tuning for optimizing the properties of amorphous phase change materials. The increased volume fraction of the MRO seems to also favor an increased nanoindentation hardness.