bluuebunny/crossref_metadata_2025 huggingface dataset:
The skewness of the distance-redshift relation in ΛCDM
Authors: Schiavone T. , Di Dio E. , Fanizza G.
Published: February 2024

Starting from a recently proposed framework for the evaluation of the cosmological averages, we evaluate the higher-order moments for the distribution of a given observable. Then, we explicitly discuss the case of the Hubble-Lemaître diagram and evaluate its skewness at the leading order in the cosmological perturbative expansion of the gravitational potential. In particular, we focus on perturbations of the luminosity distance due to gravitational lensing. Finally, we discuss our findings in view of recent numerical relativistic simulations, confirming that the skewness in the Hubble-Lemaître diagram primarily originates from the late-time matter bispectrum, with other line-of-sight projection effects being sub-dominant.
Safety, tolerability and blinding efficiency of non-invasive deep transcranial temporal interference stimulation: first experience from more than 250 sessions
Authors: Vassiliadis Pierre , Stiennon Emma , Windel Fabienne , Wessel Maximilian J , Beanato Elena , Hummel Friedhelm C
Published: February 2024

Objective. Selective neuromodulation of deep brain regions has for a long time only been possible through invasive approaches, because of the steep depth-focality trade-off of conventional non-invasive brain stimulation (NIBS) techniques. Approach. An approach that has recently emerged for deep NIBS in humans is transcranial Temporal Interference Stimulation (tTIS). However, a crucial aspect for its potential wide use is to ensure that it is tolerable, compatible with efficient blinding and safe. Main results. Here, we show the favorable tolerability and safety profiles and the robust blinding efficiency of deep tTIS targeting the striatum or hippocampus by leveraging a large dataset (119 participants, 257 sessions), including young and older adults and patients with traumatic brain injury. tTIS-evoked sensations were generally rated as ‘mild’, were equivalent in active and placebo tTIS conditions and did not enable participants to discern stimulation type. Significance. Overall, tTIS emerges as a promising tool for deep NIBS for robust double-blind, placebo-controlled designs.
Flow past a heated slippery corner
Authors: D’Alessio Serge
Published: February 2024

Discussed in this paper is the unsteady, laminar, two-dimensional, viscous flow around a corner subject to Navier-slip conditions characterized by a slip length, γ, with 0 ≤ γ ≤ 1. Comparisons with no-slip (γ = 0) boundary conditions are made to assess the impact of a slippery surface. Both isothermal and heated flows are considered including forced and mixed convection. A numerical solution procedure utilizing boundary-layer coordinates is outlined. Numerous simulations have been compiled for the Reynolds number Re = 100 and Rayleigh numbers Ra = 0, 1, 10. Various results and comparisons are presented and discussed.
Deep learning-based segmentation of breast masses using convolutional neural networks
Authors: Anghelache Nastase I-N , Moldovanu S , Moraru L
Published: February 2024

Automatic breast tumor segmentation based on convolutional neural networks (CNNs) is significant for the diagnosis and monitoring of breast cancers. CNNs have become an important method for early diagnosis of breast cancer and, thus, can help decrease the mortality rate. In order to assist medical professionals in breast cancer investigation a computerized system based on two encoder-decoder architectures for breast tumor segmentation has been developed. Two pre-trained DeepLabV3+ and U-Net models are proposed. The encoder generates a high-dimensional feature vector while the decoder analyses the low-resolution feature vector provided by the encoder and generates a semantic segmentation mask. Semantic segmentation based on deep learning techniques can overcome the limitations of traditional algorithms. To assess the efficiency of breast ultrasound image segmentation, we compare the segmentation results provided by CNNs against the Local Graph Cut technique (a semi-automatic segmentation method) in the Image Segmenter application. The output segmentation results have been evaluated by using the Dice similarity coefficient that compares the ground truth images provided by the specialists against the predicted segmentation results provided by the CNNs and Local Graph Cut algorithm. The proposed approach is validated on 780 breast ultrasonographic images of the BUSI public database of which 437 are benign and 210 are malignant. The BUSI database provides classification (benign or malignant) labels for ground truth in binary mask images. The average Dice scores computed between the ground truth images against CNNs were as follows: 0.9360 (malignant) and 0.9325 (benign) for the DeepLabV3+ architecture and of 0.6251 (malignant) and 0.6252 (benign) for the U-Net, respectively. When the segmentation results provided by CNNs were compared with the Local Graph Cut segmented images, the Dice scores were 0.9377 (malignant) and 0.9204 (benign) for DeepLabV3+ architecture and 0.6115 (malignant) and 0.6119 (benign) for U-Net, respectively. The results show that the DeepLabV3+ has significantly better segmentation performance and outperforms the U-Net network.
Molecular simulations of doxorubicin complexed with native and modified cyclodextrins in water
Authors: Mikaelian Georgios , Megariotis Grigorios , Theodorou Doros N
Published: February 2024

In this study, all-atom molecular dynamics simulations have been performed to investigate from a nanoscopic point of view the interactions in supramolecular complexes formed between doxorubicin and cyclodextrins in an aqueous phase at a temperature of 310 K. All the simulations are on the time scales of microseconds and are carried out on High Performance Computing resources provided by the Greek Supercomputer ARIS. Doxorubicin, which is a well-known anticancer drug belonging to the class of anthracyclines, is simulated with two cyclodextrins of broad utilization in drug delivery, i.e.: γ-cyclodextrin and 2-hydroxypropyl-β-cyclodextrin. In both cases, the complexation process takes place spontaneously during the course of the simulations and a detailed analysis of the formed complexes is conducted in terms of structural, dynamical and thermodynamic properties. In addition, we present a quantitative analysis of how doxorubicin affects, upon complexation, the geometry, the hydrogen bonding network and the hydration of the selected cyclodextrins. Special attention is paid to the thermodynamic description of the simulated systems. More specifically, the standard binding free energy is calculated with an extended version of the linear interaction energy method. The presented in silico approach reveals that doxorubicin forms stable complexes with the chosen cyclodextrin molecules, there is a water solubility enhancement of the drug with respect to its unbound state and also cyclodextrins act protectively to the drug preventing undesired effects, such as the glycosidic degradation. Excellent agreement is found between the presented results and published in silico and experimental findings.
Stability of dynamic fluid transport simulations
Authors: Anvari Mehrnaz , Baldin Anton , Clees Tanja , Klaassen Bernhard , Nikitin Igor , Nikitina Lialia , Pott Sabine
Published: February 2024

Pipeline transport is an efficient method for transporting fluids in energy supply and other technical applications. While natural gas is the classical example, the transport of hydrogen is becoming more and more important; both are transmitted under high pressure in a gaseous state. Also relevant is the transport of carbon dioxide, captured in the places of formation, transferred under high pressure in a liquid or supercritical state and pumped into underground reservoirs for storage. The transport of other fluids is also required in technical applications. Meanwhile, the transport equations for different fluids are essentially the same, and the simulation can be performed using the same methods. In this paper, the effect of control elements such as compressors, regulators and flaptraps on the stability of fluid transport simulations is studied. It is shown that modeling of these elements can lead to instabilities, both in stationary and dynamic simulations. Special regularization methods were developed to overcome these problems. Their functionality also for dynamic simulations is demonstrated for a number of numerical experiments.
The influence of inlet flow asymmetry on the carotid bifurcation hemodynamics
Authors: Borisov V G , Zakharov Yu N , Derbilova V P , Vinogradov R A , Ivanova N V
Published: February 2024

Arterial bifurcations are known to be high-risk areas for the initiation of atherosclerosis. The appearance and growth of atherosclerotic plaques in the bifurcation of the carotid artery can result in severe consequences such as cerebrovascular accidents. The common signs of an atherogenic risk center around the surpassing critical values by certain hemodynamic indices, which are distributed over the artery wall. These indices are related to the effect of blood flow on the arterial wall, and their distribution is influenced by both the bifurcation’s geometric shape and the flow structure at its inlet. The objective of this study is to carry out a comparative analysis of hemodynamic indices in personal-specific models of carotid bifurcation with centrally symmetric and asymmetric input flows. The examined geometric models of bifurcation are based on computed angiography data obtained from the individuals free of apparent pathology. By using computational fluid dynamics within these models, the distribution of hemodynamic indices in a steady periodic flow is calculated and critical zones are determined for them. All the models are divided into two groups – those with symmetric and those with asymmetric input flows. For each model with asymmetric input flow, an alternative geometry is designed to ensure inlet flow symmetry, and comparative numerical calculations of the blood flow are carried out. The results of comparative analysis reveal that the distribution of hemodynamic indices is simpler for the group with symmetric input flow. A comparison of the averages between these two groups with symmetrical and natural asymmetric input flows indicates a 55% better result for the latter group. Furthermore, for almost all models with asymmetric input flow, their alternative models give worse hemodynamic results. Thus, hemodynamic indices in simpler models with symmetrical input flow can serve as an upper estimate for indices in models with natural asymmetric flow. A total of 89 models are included in the study.
Modeling of Regional Economic Growth in the Conditions of Simulation of Scientific and Technical Revolution (on the example of the Republic of Tatarstan)
Authors: Elshin L A , Gafarov M R , Dinmukhametova A A
Published: February 2024

The issues of the structural organization of productive factors that trigger and intensify the economic dynamics of the regions are quite well worked out in the scientific community today. Without going into a detailed review of derivative approaches that offer modifications to the models discussed above, it must be unequivocally stated that the basic factors of economic dynamics included in the neoclassical production functions are labor, fixed capital, and scientific and technological progress (STP). At the same time, it is important to take into account that when taking into account and including in the models of production functions of scientific and technical progress, it is often understood as the potential for the creation and diffusion of innovations in the economic environment. In this work, scientific and technical progress is understood as a set of human, financial, infrastructural and institutional resources that determine the overall innovative capabilities of the region and the level of its effectiveness in the field of science and technology to solve problems in the field of ensuring the qualitative and structural parameters of economic growth and development, increasing competitiveness in the meso -, macro and global level. Relying on this approach to the definition, as well as on the methodological tools for measuring STP proposed by the authors, the study attempts to construct a Solu production function. Based on the results of the assessments, the relevant parameters of the influence of productive factors on the GRP dynamics were established (on the example of the Republic of Tatarstan), and patterns were identified that prove the priority of scientific and technological progress in shaping the prospects for economic dynamics in the conditions of the fourth industrial revolution.
Comparison of image quality and standardized uptake values (SUV) of two PET/CT imaging system using F-18 and Ga-68
Authors: Alanazi S F
Published: February 2024

Both the Gemini TOF PET/CT and Biograph mCT flow PET/CT scanners are advanced imaging systems used in clinical settings for a range of applications, including oncology, neurology, and cardiology. Both the Gemini TOF PET/CT and Biograph mCT flow PET/CT scanners are advanced imaging systems used in clinical settings for a range of applications, including oncology, neurology, and cardiology. Both systems are capable of producing high quality images with good spatial resolution and contrast. However, there are some differences between the two systems that may impact image quality. The recovery coefficient (RC) is an important parameter that is used to evaluate the image quality and the accuracy and precision of PET/CT imaging systems. In the other hand, Standardized uptake value (SUV) is A frequently utilized quantitative measure in PET/CT imaging is the estimation of radiotracer uptake within a specified region of interest (ROI). SUV measurements are possible to be used to assess tumor metabolism and monitor treatment response. Several studies have evaluated the SUV and RC measurements using different radiotracers and scanner has been found to exhibit good accuracy and precision for both radiotracers. In this work we investigated the SUV and RC values of the Gemini TOF PET/CT and Biograph mCT flow PET/CT scanners by using F18 and Ga-68 and compared their values. Methods in this work, we analyzed images acquired using two distinct PET-CT scanners from two different manufacturers; Gemini TOF PET/CT (Philips Medical Systems) system and biograph mCT flow PET/CT system (Siemens Healthineers). we assessed the SUV values by using the PET-CT cylindrical image quality NEMA phantom that was filled with F-18 and Ga-68 while the image quality measured by employing the NEMA/International Electrotechnical Commission (IEC) Torso Phantom. Results We revealed that the RC values of F-18 using Gemini TOF PET/CT ranged from 0.02 to 0.03 for different sphere sizes, where they ranged from 0.005 to 0.015 for Ga-68 and when used Biograph mCT flow PET/CT scanner RC values of F-18 ranged from 0.025 to 0.05 and for Ga-68 ranged from 0.02 to 0.042. The first section in your paper
A fast and efficient algorithm for time synchronization in satellite quantum key distribution
Authors: Miller A V
Published: February 2024

Time synchronization is one of the most crucial issues that must be addressed in developing quantum key distribution (QKD) systems. It not only lets the transmitter and the receiver to assign a sequence number to each event and then do correct basis reconciliation, but also allows to increase signal-to-noise ratio. Time synchronization in satellite communications is especially complicated due to such factors as high loss, signal fading and Doppler effect. In this work, a simple, efficient and robust algorithm for time synchronization is proposed. It was tested during experiments on QKD between Micius, the world’s first quantum communications satellite, and an optical ground station located in Russia. The obtained synchronization precision lies in the range from 467 to 497 ps. The authors compare their algorithm for time synchronization with the previously used methods. The proposed approach can also be applied to terrestrial QKD systems.
Influence of the Anderson Transition on Thermoelectric Energy Conversion in Disordered Electronic Systems
Authors: Khomchenko Ilia , Ouerdane Henni , Benenti Giuliano
Published: February 2024

So far, the efficiency of thermoelectric energy conversion remains low compared to traditional technologies, such as coal or nuclear. This low efficiency can be explained by connecting the thermoelastic properties of the electronic working fluid to its transport properties. Such connection also shows that operating close to electronic phase transitions can be an efficient way to boost the thermoelectric energy conversion. In this paper, we analyze themoelectric efficiency close to the metal-insulator Anderson transition. Our results reveal the direct link between the thermoelectric and thermoelastic properties of Anderson-type systems. Moreover, the role of the conductivity critical exponent in the thermoelectric energy conversion is analysed. Finally, we show that relatively large values of the thermolectric figure of merit may be obtained in the vicinity of the Anderson transition.
Geant4 simulations of monochromatic Cherenkov radiation in thin quartz targets for different experimental conditions
Authors: Đurnić B , Potylitsyn A , Bogdanov A , Gogolev S
Published: February 2024

In light of our recent research, we discussed the possibility of observing quasimonochromatic Cherenkov Radiation (ChR) spectral lines from a dispersive medium (thin quartz radiator). Such experimental results were verified on the Mainz Microtron MAMI, Germany [1], while both the polarization currents analytical model [2] and Geant4 [3] simulations were used to analyze the results. To describe the Cherenkov radiation process, the Geant4 toolkit uses only the approximation obtainable for an infinitely thick emitter (cos θ = 1 / βn(λ), where θ is Cherenkov’s angle of emission, β is reduced velocity, and n(λ) is a refractive index as a function of emitted radiation’s wavelength λ) and doesn’t consider its actual dimensions. Tamm’s theory [4] predicts some broadening of the ChR angular distribution with a radiator thinning. Consequently, Geant4 gave inadequate results for the pencil-like electron beams compared to the polarization currents model and the experiment. However, unlike in the analytical calculations, we needed to consider more realistic Gaussian electron beams to obtain better results with Geant4. Therefore, obtained results primarily manifest beam characteristics rather than the ChR itself, i.e., its intrinsic characteristics are masked. Now, the idea is to present additional simulation results with further variations of the quartz’s thickness (in preparation for future experiments), confirming the last conclusion without any doubt.
Numerical modeling for controlled compensation grouting
Authors: Bestuzheva A S , Chubatov I V
Published: February 2024

This article analyzes the numerical modeling of the stress-strain state of a gravity structure sand base during grouting works using the controlled compensation grouting technique. The modeling is performed using the finite element method and physical nonlinear soil models that take into account the Coulomb-Mohr strength condition. The modeling is done in the computational software JuliS as well as the universal software complex PC ZSoil. The goal of the research is to study the impacts of compensation grouting parameters on the elevation value of base slab. A model was created for the grout body as an expanding spheroid whose volume changes as cement grout is fed in the soil. The authors developed a grouting sequence for grouting solutions based on the location of grout body in the grouting pillar. It is more efficient to feed the grout starting from the lower grout body. The grouting solution feed mode is selected depending on the soil strength condition and accounting for the prevention of hydraulic fracture. As a result of the research, the initial subsidence of the soil on the daytime surface above the injection zone was obtained, which requires experimental confirmation and is a matter for discussion.
Gaussian Process-based Bayesian Optimization and Shape Transformation of Benchmark Functions
Authors: Omae Yuto
Published: February 2024

Gaussian process-based Bayesian optimization (GPBO) finds application in various fields for approximate optimization of parameters. Because the search performance depends on the shape of the black-box function, users of GPBO should know these details. Therefore, we provide some experiment results of the relationship between GPBO search performance and the shape of the black-box function. We adopted “Easom,” “Ackley,” “Bukin N.6,” “Beale,” “Rosenbrock,” and “Goldstein–Price,” which are benchmark functions for optimization problems. Moreover, we adopted logarithmic and range-transformed functions to provide deeper insight.
Simulation model parameter optimization method for multidimensional signals
Authors: Rozanov Ivan , Sotnikov Alexey , Kim Tamara
Published: February 2024

The paper describes an approach to minimize the number of simulation experiments of multidimensional signals by means of a regression neural network. Multivariate signal simulation systems are in demand for testing real-time computing systems, but they mostly have a wide vector of model parameters. The formation of parameter vector for the simulation model of multidimensional signals, which ensures an adequate solution to the problem of signal processing obtained as a result of the model operation, is an urgent task. The authors propose a method of heuristic optimization of input parameters, implemented by means of machine learning, which reduces the searching of values for the given optimization function. In this study the ability to perform real-time signal simulations is the optimization feature. The research outcomes are the description of the neural network, the rationale for its configuration, and the training and validation results.
3D scanning in Cultural Heritage: model creation and digital restoration of the tombstone of the bishop Vasilije Petrović (Negosh) in Saint Petersburg
Authors: Badillo P. D. , Parfenov V. A. , Raspopović R. , Tishkin V. O.
Published: February 2024

3D laser and optical scanning techniques are widely employed in Cultural Heritage preservation for documenting pieces of different sizes and shapes. However, due to limitations of the methods available today, the results obtained vary according to different characteristics of the object under study. External surfaces showing very smooth features make the capturing process and the posterior processing a more elaborate task, requiring special attention and additional retouching to improve the final 3D model. Tombstones are a typical example of this type of objects, combining both flat external contours and refined outlines. In this work the procedure of creation of the digital model of the tombstone of the bishop Vasilije Petrović (Negosh) is described, a piece of art which combines both technical and historical importance. Post-processing steps required involved different software (Geomagic Design X, ZBrush, Adobe Photoshop) for surface correction and cleaning, details and photorealistic texture improvements and lost material restoration.
Semi-empirical method for evaluating the robustness of QRWS algorithm for different coin sizes and functional dependence between coin phases
Authors: Tonchev H , Danev P
Published: February 2024

In this work we study the quantum random walk search algorithm when the walk coin is constructed by generalized Householder reflection and a phase multiplier. We focus on the algorithm’s robustness against errors in the phases – how the probability to find solution decreases with increasing the errors in those phases. The robustness depends on the functional dependence between the reflection phase φ and the phase multiplier ζ. Here we use interpolations by non-linear logistic regression functions to study a particular functional dependence between angles ζ = -2φ + 3π + α sin(2φ) for different coin sizes and parameters alpha. The obtained results in this work are discussed, together with their limitations.
The multifractality of the internal geomagnetic field
Authors: Peqini Klaudio
Published: February 2024

It is well established that the external geomagnetic field exhibits distinct multifractal behaviour with multiple characteristic timescales that are a manifest of the complex solar-driven dynamics of the magnetosphere or ionosphere. The internal magnetic field on the other hand is characterized by much longer timescales. Consequently, in order to observe any multifractal behaviour, there is needed a time series of magnetic dipolar moment spanning thousands or even millions of years of the past geomagnetic field of the core. Here, we analyse two series that describe the dipolar ingredient of the geomagnetic field for the last 4 and 2 million years, respectively. The first series is constructed from a continuous streak of sedimentary samples while the other series is a composite of a myriad of shorter time series contained within the 2 million years frame. We analysed the Generalized Hurst Exponent through the Multi Fractal-Detrended Fluctuation Analysis method and in each case, we observed typical multifractal structures. These results may be the manifestation of different phenomena evolving in the liquid outer core, possibly providing hints and insights into the details of the corresponding mechanisms. Analysis of the time evolution of the Generalized Hurst Exponent for each series displays a complicated behaviour. Typically the anti-persistent character of the series becomes more evident when close to e dipole reversal. Special efforts need to be dedicated in identifying connections between geomagnetic reversals and time dependence of the Generalized Hurst Exponent.
Numerical simulation of image formation in an optical device in the problem of space monitoring
Authors: Vafin K M , Kuznetsov A A , Zavialova N A , Negodiaev S S
Published: February 2024

Space monitoring systems are being developed for space object and debris observation. There are the following problems in this area: optimizing the operation of existing optoelectronic devices, locating new devices, analyzing the monitoring results of outer space. It is necessary to use modeling in order to solve these problems. In this regard, the authors aimed to investigate the process of image formation on a photodetector under specified observation conditions. A mathematical model of image formation was constructed and a software implementation of this model was developed. Synthetic images of the night sky and images of the trajectories of space objects under given conditions were formed. The obtained results were compared with real images from telescopes.
Discrepancies between reported knuckleball spin rates and dynamics
Authors: Hoskins Aaron B
Published: February 2024

Major League Baseball tracks every pitch of every game and provides the public with access to a significant amount of data for each pitch. This level of data availability is not seen in many other sports and offers substantial opportunities to provide analysis on the sport. Major League Baseball does not provide the raw data but provides refined data. While the algorithms for transforming the raw data are robust, the algorithms are not perfect. This study investigates the specific case of knuckleball pitches and shows that the equations of motion and reported spin rates do not align. This study uses the modified shooting method combined with the Levenberg–Marquardt algorithm to determine the trajectories of the pitches based on the provided data and known equations of motion. This study investigates three scenarios: 1) the reported data are correct; 2) the pitches are correctly identified, but the spin rates are incorrect; and 3) the spin rates are correct, but the pitches are incorrectly identified as knuckleballs. We show that the reported data are inconsistent with the equations of motion and that, based on statistical analysis, the pitch identification is likely incorrect.
Building Empathy in Students by Developing Cyber-Physical Projects Through Design Thinking
Authors: Stoev Petko , Stoeva Maya
Published: February 2024

Empathy is a fundamental aspect of human behavior through which people build civilized social and interpersonal relationships. It is related to showing empathy, understanding and support, forming effective communication, dealing with conflict and is part of those factors that contribute to building a more compassionate and humane society. Despite its innate predisposition, the development of empathy is influenced by a number of factors, including learning. Developing projects through design thinking can be an effective way to foster and cultivate it in students. Applying a human-centered method such as design thinking to the process of project work enables them to develop a deeper understanding of others, build empathy, and generate solutions that respond to real-world problems. This paper explores the possibilities for achieving this goal and presents the results of a project-based learning experience integrating design thinking
Inverse Problem of Parameter Identification for Extended Compositional Gradient Model
Authors: Kusochkova E V , Indrupskiy I M
Published: February 2024

In this study we address simulation of initial distribution of fluid composition in hydrocarbon reservoirs, particularly in scenarios where slow vertical segregation in a low-permeability near-critical reservoir results in an incomplete relaxation to the quasi-equilibrium state. To effectively analyze these complex scenarios, we propose an extended compositional gradient model that takes into account incomplete system relaxation. Practical application of the method involves solution of the forward problem of compositional profiling, with the model parameters adjusted according to real fluid samples. We formulate the inverse problem of parameter identification for the extended compositional gradient model and solve it using gradient-free optimization methods. The adjusted parameters are specific enthalpies of fluid components and the relaxation parameter. The overarching goal of parameter identification is to closely match the predictions of the model with real data, thereby enhancing the reliability of forecasts regarding distribution of fluid composition. We believe that the results of this study will significantly influence both understanding and simulation techniques for distribution of hydrocarbon components in natural reservoirs, particularly in situations characterized by incomplete system relaxation.
Updated BBN constraints on non-equilibrium active-sterile neutrino oscillations
Authors: Panayotova Mariana , Kirilova Daniela
Published: February 2024

Big Bang Nucleosynthesis (BBN) offers impressive agreement between the predicted by theory and the observationally obtained abundances of primordially produced light elements and therefore it is used as one of the most reliable probes of the physics beyond Standard Model. The highly accurate recent determination of the primordial Deuterium and Helium-4 allows to provide updated and strengthened BBN constraints on beyond Standard Model Physics. We have provided numerical analysis of more than hundred BBN models with nonequilibrium electron-sterile neutrino oscillations with different oscillation parameters and we have constructed isohelium contours based on 1% and 3% Helium-4 uncertainty and different initial population of the sterile neutrino state. We present here updated and more strict BBN constraints on the parameters of non-equilibrium active-sterile neutrino oscillations considering several models of beyond Standard Model Physics.
Diamagnetic corrections to low-excited electronic states of light molecular systems
Authors: Danev P , Tonchev H , Stoyanov Zh , Mutafchieva Y
Published: February 2024

Compact astrophysical objects like white dwarfs and neutron stars generate very strong magnetic fields. In their atmosphere, accretion disks, and the interstellar medium surrounding them, the predominant matter consists of hydrogen, helium and few-particle atoms and molecules. In this work, we have studied the effects of strong magnetic fields on light atomic and molecular systems like hydrogen molecular ions and antiprotonic helium. The full energy of the investigated systems is calculated in the Born-Oppenheimer approximation for a few low-lying electronic states. We investigate the case where the leading effect comes from the quadratic magnetic field term in the interaction Hamiltonian. The electronic energies and wavefunctions are computed in spheroidal coordinates by a finite difference method on a nonequidistant grid. The diamagnetic contributions to the total energy for an arbitrary value of the magnetic field strength are also calculated in perturbation theory. Then they are compared with the exact results, and where possible - with previous calculations. The electronic energy terms could be used for precise computations of the spectral lines of the hydrogen molecular ion and antiprotonic helium. This will allow searching for objects, like neutron stars and white dwarfs with strong magnetic fields, containing such molecular systems in their atmospheres or accretion discs. When the effects from the approximations are taken into account, the tabulated results presented in this work could also find an application in studies for much weaker magnetic field strengths existing in laboratory environments.
Increasing of Compression Efficiency for Genomic Data by Manipulating Empirical Entropy
Authors: Aldemir Erdoğan , Oğraş Hidayet
Published: February 2024

Sharing bio-informatics data is the key point to constructing a mobile and effective telemedicine network that brings with it various difficulties. A crucial challenge with this tremendous amount of information is storing it reversibly and analysing terabytes of data. Robust compression algorithms come up with a high rate of text and image compression ratios. However, the achievement of these advanced techniques has remained in a limited range since, intrinsically, the entropy contained by the raw data primarily determines the efficiency of compression. To enhance the performance of a compression algorithm, entropy of raw data needs to be reduced before any basic compression which reveals more effective redundancy. In this study, we use reversible sorting techniques to reduce the entropy thus providing higher efficiency in the case of integrating into compression technique for raw genomic data. To that end, permutation-based reversible sorting algorithms, such as Burrow-wheeler, are designed as a transform for entropy reduction. The algorithm achieves a low-entropy sequence by reordering raw data reversibly with low complexity and a fast approach. The empirical entropy, a quantitative analysis, shows a significant reduction of uncertainty has been achieved.
Mathematical Modeling of Consciousness for Unifying Causation, Relativity and Quantum Mechanics
Authors: Samarawickrama Mahendra
Published: February 2024

Quantum physics and gravity are two different concepts which need to be unified in a widely acceptable way. While electromagnetism, weak nuclear force, and strong nuclear force were accurately unified under the framework of quantum field theory, gravity remains elusive and couldn’t be unified with quantum mechanics. However, gravity is accurately understood by the theory of relativity, which is not complementing quantum physics. This elusiveness is due to the missing consciousness dimension in the mathematical frameworks of fundamental physics, which can explain the causation of gravity, quantum mechanics, and reality. Intricately interweaving the dimension of consciousness with the mathematical frameworks of fundamental physics can make our understanding of reality complete.
Energy conservation uncertainly due to the use of an implicit time integration method clarified by a multiplexed TGV inviscid flow
Authors: Chitose Makoto , Suzuki Hiroki , Kouchi Toshinori
Published: February 2024

This study attempts to elucidate the conservation errors induced by the implicit time integration method within a multiscale flow. Using the multiplexed Taylor analytical solution as the initial field, three distinct multiscale turbulence fields were formulated, each characterised by different wavenumber attributes. A two-dimensional inviscid flow field, replicated in a computational domain with a side of 2π and subject to periodic boundary conditions, was used to illuminate kinetic energy conservation errors. The implicit time integration method - specifically the second-order accurate Crank-Nicolson method - was compared with explicit methods, such as the second-order accurate Adams-Bashforth and third-order accurate Runge-Kutta methods. The study also examines the differences between the analytical Taylor solution and a random flow field, particularly in their satisfaction of the Navier-Stokes equations and wavenumber composition, while highlighting the need for preliminary analysis for random flow fields prior to validation calculations.
Study of Geometries and Stability for Energy Density in Electromechanical Battery Flywheels with a Gaussian Shape
Authors: Coppede Daniel , Silva Bortoli Fabio da , Goncalves de Moura Andre Carlos , Losada Moreira Joao Manoel , Frajuca Carlos
Published: February 2024

A study on flywheels materials and geometries is presented here with the use of finite element modeling (FEM) simulations. The study analyzes the stress behavior of flywheel rotors subject to the rotational speed that creates the maximum stress that the flywheel can support, and then calculates the rotational energy mass ratio for each geometry. The obtained geometry was Gaussian section for the Flywheel rotor. The material used in this case study is carbon fiber Hexcel UHM 12000. The best results were a rotational speed of ≈ 279.000 rpm and rotational energy density of ≈ 440 Wh/kg. Then, to increase the total energy, Flywheel with 2 and 3 rotors were analyzed. Then the stability under rotation of these Flywheels were analyzed, some instability was found and a solution was presented.
Flap Gate Weir Structural Design Using FEA
Authors: Bamrungwong Joompon
Published: February 2024

A flap gate weir commonly use to raise the level of a river or stream. It is a device that is used to regulate the flow of water in a river. It is typically located at the upstream of the river. Basically, flap gate weir is submerged under water, so hydrostatic force acting on submerged surfaces weir. The traditional design and analysis the resultant force acting on a submerged weir surface must specify magnitude of the force, direction of the force and line action of the force all is assumed on 2D which take long time calculation and might mistake. The aims of this paper is using finite element method design and study the flap gate weir structure instead of traditional analysis. In this paper the 3D model of flap gate weir was created by SolidWorks as assembly of flap gate weir which the flap gate weir was inclined 30 degrees and imported into Ansys Workbench for boundary conditions and calculations. The result from Ansys is used to find the specific hydraulic cylinder as the system needed. And modal analysis to check the vibration of the flap gate weir. By using finite element analysis the results study is satisfy by get results faster, know total deformation, know weak point and know where reinforce pad should put in and saving cost of materials when compare with traditional analysis.
Artificial Intelligence Algorithms for Prediction and Diagnosis of Air Pollution Affecting Human Health
Authors: Garlík Bohumír , Přívětivý Jan
Published: February 2024

The complexity and growth of data in healthcare means that artificial intelligence (AI) will be increasingly applied in this area. This article (study) de-scribes the types of AI used by care providers and life and biophysical sciences companies. This paper describes the structure of the methodology of artificial intelligence (AI) algorithms and its machine learning (ML) subsystem with respect to the prediction of environmental pollution and its negative impact on humans. Key categories of AI applications focus on diagnosis and treatment or referral, patient engagement and adherence, and administrative activities. Diagnosis of diseases is a crucial and very important task of the physician in planning the right treatment and ensuring the health status of patients. The application of artificial intelligence (AI) can improve the level of diagnostic accuracy and efficiency. Indoor air quality (IAQ) is an important issue for well-being and good health, as most people spend almost all of their time in different types of buildings. Given the increasing availability of data and the rapid expansion of AI techniques, it is essential to explore the development of indoor and outdoor air quality predictions using AI techniques to improve and maintain IAQ.
Calculations of the diffusion coefficients in gases and liquids by the molecular dynamics method
Authors: Kharlamov G V
Published: February 2024

In this paper the calculation results of the diffusion coefficients in gases and liquids by the method of molecular dynamics are presented. The modified intermolecular Lennard-Jones potential has been used. The diffusion coefficients dependences on temperature and density have been calculated. Using the diffusion coefficients dependence on temperature it has been found, that the collisional mechanism in rarefied and dense gases changed for the collective one in liquids. In the field of the thermodynamics parameters of two phase coexistence, drops of liquid occur in the vapour or bubbles occur in the liquid. The comparison of the experimental data with our calculations results in a satisfactory agreement.
Generalization of numerical simulation results on the electrical coalescence threshold for two conducting droplets based on non-dimensional parameters
Authors: Chirkov V A , Kostin P A
Published: February 2024

Electrocoalescence, the physical process underlying the demulsification of a dielectric dispersion medium containing small conductive droplets (e.g., water), involves droplet merging at low electric fields and splashing at higher voltages. Understanding the physics of electrocoalescence is crucial for optimizing industrial electrocoalescers. However, mathematical modeling of these complex, multiphysics phenomena is challenging, and many published results are questionable. In this study, we utilized a previously developed reliable model for computing the threshold between electrical coalescence and non-coalescence. We investigate the applicability of dimensionless parameters, such as the Ohnesorge number and Weber electric number, to describe the coalescence threshold for uncharged droplets of equal size. Using COMSOL Multiphysics software, we analyze the dependency of the threshold electric field strength on water droplet radius and establish an equivalent dimensionless relationship. Our findings reveal that a universal Weber number quite accurately describes the threshold over a wide range of droplet radii, regardless of changes in liquid viscosity and inter-electrode gap. Direct mathematical simulations using up-to-date numerical models enable us to determine non-dimensional parameter values corresponding to the threshold electric field strength, providing generalizable results.
Discretization schemes for the two simplified global double porosity models of immiscible incompressible two-phase flow
Authors: Jurak M , Pankratov L , Vrbaški A
Published: February 2024

We present the discretization schemes for the two simplified homogenized models of immiscible incompressible two-phase flow in double porosity media with thin fractures. The two models were derived previously by the authors by different linearizations of the nonlinear local problem called the imbibition equation which appears in the homogenized model after passage to the limit as ε → 0. The models are fully homogenized with the matrix-fracture source terms expressed as a convolution.
Numerical Investigation of Stress-Strain State Effects on Strain Measurements with Fiber Bragg Grating Sensors
Authors: Matveenko V P , Serovaev G S
Published: February 2024

This study investigates the behaviour of resonant wavelengths of Fiber Bragg Gratings (FBG) inscribed within optically isotropic fibers under transverse loading, both in free and embedded conditions. A numerical-analytical approach is employed, utilizing the finite element method to calculate strain tensor components in the optical fiber core, followed by an analytical determination of resonant wavelengths and reflected FBG spectrum shape. The research demonstrates the influence of the ratio of host material and optical fiber elastic moduli on the birefringence level in FBG area under transversal loading. Based on analytical model of FBG spectrum simulation the discrepancy between analytically calculated and experimentally recorded resonant wavelength shifts in FBG embedded within isotropic material under varying transverse load levels is demonstrated.
Effects of Reynolds number and blockage ratio on the turbulence characteristics of open channel flow passing through trash rack
Authors: Kokkiligadda Gangadhar , Dhar Anirban , Reddy Hanmaiahgari Prashanth
Published: February 2024

Trash racks are extensively used to prevent debris from being transported to down-stream reaches of waterways. However, debris accumulation at the screens can significantly affect their hydraulic performance, resulting in negative economic and environmental consequences. Basic research related to the mechanism of these physical processes is still rather limited. In this experimental study, the flow fields, including the turbulence intensities, Reynolds stresses, and turbulent kinetic energy near a trash rack in a fixed-bed open channel for subcritical flow conditions are investigated for two Reynolds numbers and two blockage ratios. The experimental study investigates the important physical mechanisms relating to turbulence generation and possible sediment deposition induced by the vertical trash rack. Reynolds number effect on time mean streamwise velocity is predominant in the trash rack’s downstream free surface layer as a higher Reynolds number flow has higher normalized streamwise velocity in the free surface layer and lower in the inner layer. In both the Reynolds number effect case and the blockage ratio effect case peak normalized turbulent kinetic energy was observed immediately downstream of the trash rack and with the increment of longitudinal distance downstream of the trash rack, normalized Turbulent kinetic energy is decreased.
Evaluation of word embedding models used for diachronic semantic change analysis
Authors: Maslennikova Yulia , Bochkarev Vladimir
Published: February 2024

In the last decade, the quantitative analysis of diachronic changes in language and lexical semantic changes have become the subject of active research. A significant role was played by the development of new effective techniques of word embedding. This direction has been effectively demonstrated in a number of studies. Some of them have focused on the analysis of the optimal type of word2vec models, hyperparameters for training, and evaluation techniques. In this research, we used Corpus of Historical American English (COHA). The paper demonstrates the results of multiple training runs and the comparison of word2vec models with different variations of hyperparameters used for lexical semantic change detection. In addition to traditional word similarities and analogical reasoning tests, we used testing on an extended set of synonyms. We have evaluated word2vec models on the set of more than 100,000 English synsets that were randomly selected from the WordNet database. We have shown that changing the word2vec model parameters (such as a dimension of word embedding, a size of context window, a type of model, a word discard rate etc.) can significantly impact on the resulting word embedding vector space and the detected lexical semantic changes. Additionally, the results strongly depended on properties of the corpus, such as word frequency distribution.