bluuebunny/crossref_metadata_2025 huggingface dataset:
Aloe vera gel (Aloe barbadensis miller) derived self-assembled flower-shaped carbon quantum dot interface for ultra-sensitive electrochemical detection of the endocrine disruptor bisphenol-A
Authors: Srivastava Ankur , Singh Kshitij RB , Ahmed Khrsheed , Singh Ravindra Pratap , Pandey Mrituanjay D. , Pandey Shyam S. , Singh Jay
Published: February 2024

This manuscript is focused on the synthesis of biologically derived carbon quantum dots (CQDs) via hydrothermal methods using Aloevera leaves (Aloe barbadensis miller).
Origin of electrocatalytic nitrogen reduction activity over transition metal disulfides: critical role of in situ generation of S vacancy
Authors: Wang Tianyi , Guo Zhongyuan , Oka Hirofumi , Kumatani Akichika , Liu Chuangwei , Li Hao
Published: February 2024

We identified an interesting electrochemistry-driven “in situ” generation of S-vacancies of transition metal disulfides, which serves as an origin of promising electrochemical ammonia synthesis activity.
Elucidating shape-mediated drug carrier mechanics of hematite nanomaterials for breast cancer therapeutics
Authors: Babunagappan Kaviya Vijayalakshmi , Raj Thilak , Seetharaman Abirami , Ariraman Subastri , Sudhakar Swathi
Published: February 2024

Cisplatin-loaded EHNP exhibited a higher cellular uptake rate than Cispatin-loaded SHNP. This effect resulted in high cellular cytotoxicity and cell cycle arrest for cells treated with cis-EHNP at much lower concentrations than cis-SHNP-treated samples.
Bivalent chromatin: a developmental balancing act tipped in cancer
Authors: Glancy Eleanor , Choy Natalie , Eckersley-Maslin Melanie A.
Published: February 2024

Bivalent chromatin is defined by the co-occurrence of otherwise opposing H3K4me3 and H3K27me3 modifications and is typically located at unmethylated promoters of lowly transcribed genes. In embryonic stem cells, bivalent chromatin has been proposed to poise developmental genes for future activation, silencing or stable repression upon lineage commitment. Normally, bivalent chromatin is kept in tight balance in cells, in part through the activity of the MLL/COMPASS-like and Polycomb repressive complexes that deposit the H3K4me3 and H3K27me3 modifications, respectively, but also emerging novel regulators including DPPA2/4, QSER1, BEND3, TET1 and METTL14. In cancers, both the deregulation of existing domains and the creation of de novo bivalent states is associated with either the activation or silencing of transcriptional programmes. This may facilitate diverse aspects of cancer pathology including epithelial-to-mesenchymal plasticity, chemoresistance and immune evasion. Here, we review current methods for detecting bivalent chromatin and discuss the factors involved in the formation and fine-tuning of bivalent domains. Finally, we examine how the deregulation of chromatin bivalency in the context of cancer could facilitate and/or reflect cancer cell adaptation. We propose a model in which bivalent chromatin represents a dynamic balance between otherwise opposing states, where the underlying DNA sequence is primed for the future activation or repression. Shifting this balance in any direction disrupts the tight equilibrium and tips cells into an altered epigenetic and phenotypic space, facilitating both developmental and cancer processes.
The art of hijacking: how Nsp1 impacts host gene expression during coronaviral infections
Authors: Karousis Evangelos D.
Published: February 2024

Non-structural protein 1 (Nsp1) is one of the first proteins produced during coronaviral infections. It plays a pivotal role in hijacking and rendering the host gene expression under the service of the virus. With a focus on SARS-CoV-2, this review presents how Nsp1 selectively inhibits host protein synthesis and induces mRNA degradation of host but not viral mRNAs and blocks nuclear mRNA export. The clinical implications of this protein are highlighted by showcasing the pathogenic role of Nsp1 through the repression of interferon expression pathways and the features of viral variants with mutations in the Nsp1 coding sequence. The ability of SARS-CoV-2 Nsp1 to hinder host immune responses at an early step, the absence of homology to any human proteins, and the availability of structural information render this viral protein an ideal drug target with therapeutic potential.
Adaptability Specifications of No-Till Farming in the Krasnodar Territory
Authors: Yudina Elena , Rinas Nikolay , Papusha Sergey , Malashikhin Nikolay
Published: February 2024

Soil cultivation technologies, applied in the farming system of the Krasnodar region and their impact on changes in the soil organic composition, have been analyzed. Advantages and disadvantages of no-till farming technology, the relationship between the mechanic means in-use and agrotechnical requirements, have been substantiated. Strategy for obtaining competitive agricultural products with a minimum production cost, has been stated. Advantage of multifunctional units in applying no-till farming, has been shown. Crop rotations, recommended for no-till farming application in conditions of the Krasnodar Territory, have been analyzed. Fuel economy in applying no-till farming can reach 40...50%.
Apple Flower Recognition Using Convolutional Neural Networks with Transfer Learning and Data Augmentation Technique
Authors: Kutyrev Alexey , Andriyanov Nikita
Published: February 2024

Automated monitoring of apple flowers using convolutional neural networks will enable informed decision-making for planning thinning and fruit set operations, optimizing crop load, preventing fruiting periodicity, and enhancing crop quality. The article presents the results of apple flower recognition quality on images using the YOLOv8 (You Only Look Once version 8) convolutional neural network model with the application of transfer learning and data augmentation technique. Pre-trained weights on the Common Objects in Context (COCO) dataset were utilized in the research. To expand the dataset and enhance model performance, the tools Flip, 90° Rotate, Crop, Rotation, Shear, Grayscale, Hue, Saturation, Brightness, Exposure, Blur, Noise, and Cutout were applied. The result showed that artificial augmentation of the training dataset significantly improves the quality of training for the YOLOv8 convolutional neural network model, increasing the average accuracy of detecting class features apple flowers. The analysis of the Precision-Recall curve allowed establishing a classification threshold (0.47) that provides the optimal balance between precision and recall in recognizing apple flowers at the flowering stage in images. The mAP metric for recognizing the «flower» class (flowers in the flowering stage) was 0.595. The analysis of the obtained results revealed an increase in the Precision metric by 2.1%, Recall metric by 10.13%, and mAP@0.5 metric by 5.31% when using the augmentation technique. The obtained results indicate a significant improvement in the performance of the model in recognizing apple flowers when applying the augmentation technique to the training dataset.
Comparative Agrotechnological Assessment of Disk Tillage Tools
Authors: Konovalov Vladimir , Konovalov Sergey , Strakhov Alexander
Published: February 2024

Currently, in Krasnodar Territory, disk tools are most often used for surface tillage. The efficiency of using disk tools primarily depends on the design and technological layout of their working bodies, soil and climatic conditions of operation and the number of working passages through the field. The article presents an agrotechnical assessment of disk tillage tools based on open data from machine testing stations of the Russian Federation. Based on the results obtained, the main agrotechnical performance parameters that do not meet generally accepted requirements are determined.
Substantiation of the Theory of Forces Calculating in a Steel Winch Cable for Lifting Seed Material to the Upper Tiers of Hydroponic Installations
Authors: Sokolenko Oksana , Korol Ilya
Published: February 2024

Hydroponic green fodder (HGF) is a product containing a full range of required nutrients and vitamins. To implement this technology, it is necessary to develop not only basic hydroponic installations, but also additional devices that reduce the labor intensity of production of HGF. The purpose of the research is the theoretical substantiation of the dynamics of the system “winch – steel cable of variable length – end load. The conclusion and solution of a system of second-order differential equations with variable dynamics coefficients of elements of a lifting installation (winch) are given. In addition, dependencies have been compiled to determine the elongation and force in the lifting cable.
Energy-Saving Method of Basic Tillage and Soil and Design for Its Implementation
Authors: Belousov Sergey , Kambulov Sergey , Rykov Victor , Yuzenko Julia
Published: February 2024

The article is devoted to the analysis of mechanization tools for mineral fertilizer application systems of enterprises of various forms of ownership, which can be used for implementation into the production process. This will allow us to further develop a machine design that would be able to fully meet the initial agrotechnical requirements for working in conditions of limited land use. We conducted a patent search using publicly available tools.
Technologies to reduce greenhouse gas emissions in pig farms
Authors: Tagaeva T.O. , Savina A.I.
Published: February 2024

The paper assesses greenhouse gas emissions in pig breeding in Russia as a whole and in the Novosibirsk Region, including the Kudryashovsky pig farm of Sibagro Holding. A comparative assessment of greenhouse gas emissions among all of Sibagro's pig farms was carried out. The best available technologies that can be applied in pig farms were studied in detail and the resulting assessments of the possibility of applying the best available technologies used in pig breeding were made.
Approaches to the effective implementation of SWAG-technology and technology for intrastratal carbon dioxide generating
Authors: Gorelkina Evgeniya
Published: February 2024

This article provides an overview of the results of studies of water-gas methods and carbon dioxide generation in reservoir conditions as methods for increasing oil recovery. It is shown that the efficiency of technology implementation is influenced by the choice of technical device and the composition of the selected agents selected for injection into the reservoir. The effectiveness of the implementation of these methods is directly influenced by reservoir conditions (pressure and temperature), as well as the mineralization composition of the liquid phase (injected in the form of a water-gas mixture or formation water). It turned out that in the case of an optimal mineralization composition of the liquid, the technological efficiency of the methods increases. In other cases, it is necessary the composition and concentration of surfactants are given. Recommendations on the composition and concentration of surfactants are given. To implement methods in a specific field, it is recommended to conduct laboratory studies to determine the optimal composition of the agent acting on hydrocarbon-saturated rock.
Examining the northern region of Iraq and the imperative for establishing photovoltaic power stations
Authors: Rady Nbras , Shevlyugin Maxim , Maytham Khudhair
Published: February 2024

The construction of a photovoltaic (PV) plant in the Iraqi province of Salah al-Din marks a significant step towards enhancing the region's energy infrastructure and transitioning towards sustainable, renewable energy sources. The project aims to harness the abundant solar resources in the area to generate clean and reliable electricity, contributing to both environmental sustainability and energy security. The chosen location, Salah al-Din province, is strategically positioned to receive ample sunlight, making it an ideal site for a photovoltaic installation. This solar plant is expected to have a considerable impact on the local energy landscape by diversifying the energy mix and reducing reliance on conventional, non-renewable sources. The construction process involves the installation of photovoltaic panels designed to capture and convert solar radiation into electricity. These panels, often mounted on support structures, form an array that maximizes exposure to sunlight. The energy generated by the PV plant is then fed into the local power grid, supplementing the existing energy supply. The benefits of this solar initiative extend beyond environmental considerations. The project is likely to create employment opportunities during the construction phase, boosting the local economy. Additionally, the operation of the photovoltaic plant will contribute to reducing greenhouse gas emissions, aligning with global efforts to combat climate change. Furthermore, the PV plant in Salah al-Din exemplifies Iraq's commitment to embracing renewable energy solutions as part of its sustainable development agenda. As the world transitions towards cleaner energy sources, projects like these play a crucial role in meeting the growing energy demand while mitigating the environmental impact associated with traditional energy generation. In conclusion, the construction of a photovoltaic plant in Salah al-Din energy a represents infrastructure, environmental sustainability, and energy resilience for the Iraqi province and contributing to the broader global shift towards clean and sustainable energy systems.
Use of the heat of exhaust fluge gases of gas turbine units in recovery boilers for heat and electric supply systems
Authors: Samatova Sh.Y. , Khamraev Sh.G. , Zakirova I.Z. , Fayzullaev I.M. , Chorieva S.
Published: February 2024

In this article, the inextricable interconnection and interdependence of the conditions for ensuring the heat of energy consumption is considered. A highly efficient installation covers the heat and energy needs of the Mubarek gas processing plant. With simultaneous operation of gas turbine and steam boiler plant efficiency reaches 95%. The introduction of the proposed development will solve the problem of energy and resource-saving, enables the use of a steam boiler in heat supply and solves an environmental problem.
Results of experimental studies of microwave processing of biological substrates in a hybrid microwave electrotechnological installation
Authors: Tukhvatullin M.I.
Published: February 2024

The creation of a hybrid microwave electrotechnological installation for microwave processing of biological substrates will significantly increase both the economic and energy efficiency of the installation, due to the simultaneous thermal and non-thermal processing of materials. In a microwave electrotechnological installation, it is possible to process two or more types of products with improved qualities, as a result of which it is possible to significantly increase profits at the same energy costs. The work presents a hybrid microwave electrotechnological installation, in which it is possible to carry out microwave processing of organic materials of plant origin, as well as agricultural crops. A general view of the hybrid microwave electrotechnological installation and its mathematical model are presented. The results of experimental studies of the modes of microwave processing of organic materials of plant origin in a microwave electrotechnological installation are presented. As a result of microwave processing of organic materials of plant origin, as well as agricultural crops, in a hybrid microwave electrotechnological installation, their processing time is significantly reduced, while ensuring the required quality of the dried material.
Tungsten coating technologies for agricultural machinery engine parts
Authors: Strekalina Daria , Podust Elena , Yakushko Egor , Cheka Polina , Shamaeva Ulyana
Published: February 2024

The article reviews the possibilities of using tungsten for engine parts of agricultural machinery and the transition to electric motors. The use of electric motors for agricultural machinery and experience in the production of electric tractors is described. A description of the manufacturers of electric tractors and their advantages is given. The materials of motor parts are described, including the use of tungsten. CVD coatings are selected and described as a technology for electric motor applications. The technology of obtaining tungsten coatings on the electrodes of the engine of agricultural machinery by the method of obtaining CVD coatings is proposed. In this article, the CVD coating mode is selected and the properties of the obtained coating according to the selected mode are analysed. The advantages of the coating are identified and the future development of the technology is described.
Simulation of the movement of shallow water along furrows during surface irrigation
Authors: Avlakulov M. , Saidov I.E. , Fayziev Sh.Sh.
Published: February 2024

The article presents a mathematical model of the movement of irrigation water along furrows. This work is aimed at determining the movement of water and the possibility of correctly adjusting its movement. Based on the above conditions, this article provides a more correct description of the dynamics of surface waters, necessary to take into account dispersion effects.
Impact of Physiological Fluctuations of Sex Hormones During the
Menstrual Cycle on Glucose Metabolism and the Gut Microbiota
Authors: Schieren Alina , Koch Sandra , Pecht Tal , Simon Marie-Christine
Published: February 2024

Diabetes mellitus is one of the most prevalent chronic diseases. Previous studies
have shown differences in glucose metabolism between males and females.
Moreover, difficulties in medication adherence have been reported in females
with type 2 diabetes. These observations are believed to be caused by
fluctuations in sex hormone concentrations during the menstrual cycle.
Furthermore, gut microbiota is linked to female host metabolism and sex hormone
production. Understanding the interactions between fluctuating hormone
concentrations during the menstrual cycle, gut microbiota, and glucose
metabolism in humans is significant because of the increasing prevalence of
diabetes and the consequent need to expand preventive efforts. A literature
search was performed to determine and summarize the existing evidence, deduce
future research needs to maintain female health, and investigate the
relationship between the physiological menstrual cycle and glucose metabolism.
Studies from 1967 to 2020 have already examined the relationship between
variations during the menstrual cycle and glucose metabolism in healthy female
subjects using an oral-glucose tolerance test or intravenous glucose tolerance
test. However, the overall number of studies is rather small and the results are
contradictory, as some studies detected differences in glucose concentrations
depending on the different cycle phases, whereas others did not. Some studies
reported lower glucose levels in the follicular phase than in the luteal phase,
whereas another study detected the opposite. Data on gut microbiota in relation
to the menstrual cycle are limited. Conflicting results exist when examining the
effect of hormonal contraceptives on the gut microbiota and changes in the
course of the menstrual cycle. The results indicate that the menstrual cycle,
especially fluctuating sex hormones, might impact the gut microbiota
composition.

The menstrual cycle may affect the gut microbiota composition and glucose
metabolism. These results indicate that glucose tolerance may be the greatest in
the follicular phase; however, further well-conducted studies are needed to
support this assumption.
Exploring the backward and forward linkages of production network in a developing country
Authors: Ahmad Imtiaz , Alvi Shahzad
Published: February 2024

This paper applies social network analysis (SNA) techniques to the input–output table in order to investigate the production network of Pakistan’s economy. Through different network measures, it identifies the sectors that exert significant direct and indirect impacts on other sectors. The findings reveal that, overall, sectors have weak forward linkages relative to backward linkages. The services sectors, particularly transportation and trade services, have the highest out-degree (a measure of forward linkages). In contrast, the manufacturing sectors demonstrate comparatively lower connectivity than the services sectors. The sectors of electricity, petroleum, and chemicals emerge as the most widely utilized inputs across various industries. Despite their relatively moderate immediate absorption in downstream industries, these sectors possess the potential to affect other industries indirectly. Considering the combined measures of network analysis, these sectors also emerge as the most crucial sectors in Pakistan’s production network. This suggests that enhancing efficiency in the energy, refining, and petrochemical industries will yield the highest economy-wide impact.
The mothers: contesting health-illness status and cultural authority in the age of AIDS
Authors: Gugliotti João Paulo , Miskolci Richard
Published: February 2024

Despite the relevance and prevalence of research that produced knowledge about stigmatised groups and communities throughout the 1980s and 1990s, in the United States, studies that investigated the relationship between HIV/AIDS, intersectional stigma, and health-illness status among groups considered hegemonic are incipient—i.e., heterosexual, and white groups, who did not suffer stigma due to sexuality and race/colour, for example. In this study, such a gap is examined in order to observe the effects of stigma in non-exposed communities. Additionally, the article (i) explores the formation of a pioneering group of caregivers in New York City, the Mothers of Patients with AIDS (MPWA), created in 1986; and (ii) analyses narratives about health disease from a collective care agenda established by middle-aged and elderly mothers dealing with the challenges and needs of adult children and people with moderate and high degrees of dependence. This study is part of a larger project that investigated the emergence of non-profit organisations and gerontology care groups in the context of the HIV-AIDS epidemic in New York in the 1980s and 1990s. Documentary research was developed in the Florence Rush collection, made available by the Arthur and Elizabeth Schlesinger Library at Harvard University’s Radcliffe Institute for Advanced Study. The selected materials bring together qualitative empirical sources from reports, personal histories, and interviews conducted by Florence Rush and other mothers, social workers, and health professionals. As the results attest, the narratives produced by Florence Rush’s interlocutors during the AIDS health crisis make it possible to understand how social and cultural dynamics of recognising the disease did not result in autonomous, individual, and objective processes for exposing the pathological state. The strategic use of the term “cancer” instead of “AIDS” as an umbrella definition, and one less demarcated by aspects involving gender and sexual behaviour, evidenced the sociality of the illness. Conclusions show how negative representations were associated with AIDS—perceived as harmful, immoral, or deviant behaviours — and produced new meanings and demands among patients who feared stigmatising classifications in the midst of sexual panic until the commercial availability of the antiretroviral cocktail in 1997.
Dissociation of composite Abrikosov vortices in two-band superconductors in a strong rf field
Authors: Pokusinskyi A. O. , Kasatkin A. L.
Published: February 2024

In several theoretical works, it was argued that under certain conditions Abrikosov vortices in multiband superconductors can split and exist in the form of fractional vortices, formed separately in superfluid condensates of different electron bands. Such vortices possess a fractional flux quantum, and these fractional vortices attract each other, trying to join into a composite vortex with the whole flux quantum ϕ0=h/2e. In the present work, we solve numerically the nonlinear dynamic equation for the composite vortex, settled in the pinning potential well of the columnar defect within a two-band superconductor, and exerted the rf Lorentz force action. We demonstrate that at high enough rf current amplitudes such composite Abrikosov vortices will dissociate into fractional ones and escape from the pinning potential well. The sequence of these events depends on the character of the pinning potential well, e.g., the radius of the pinning potential well. The possible manifestation of such kind transitions in rf electrodynamic characteristics, such as a complex rf resistivity and harmonics generation is calculated.
Dynamics of magnetic vortices in the field of local inhomogeneity of a ferromagnet
Authors: Kovalev A. S.
Published: February 2024

The rotation of a magnetic vortex in a ferromagnet with a local smooth change in the exchange interaction is considered. The frequency of this precession is found for all distances of the vortex from defect center. The rotation velocity of the vortex nonmonotonically depends on the distance to the center, reaching a maximum at a distance of the order of the characteristic dimension of the defect. The decrease in velocity at large distances agrees with the data known in the literature. Accounting of attenuation leads to the vortex escape the defect or falling onto it along a logarithmic spiral.
High-frequency dissipative MHD waves in straight magnetic cylindrical plasma: Coronal loops heating application
Authors: Kumar Ankit , Pandey V. S.
Published: February 2024

The theoretical model for analyzing the waves and oscillatory behavior in the structured solar corona using straight magnetic cylindrical geometry filled with uniform low-β plasma has been recognized as the most preferable classical model for the last few decades. A number of observations, since the first observation of the transition region and coronal explorer to the latest ones, have been adequately explained by adopting this model. In order to analytically formulate the oscillatory characteristics of magnetohydrodynamic (MHD) waves, most of the studies have considered the nature of plasma as an ideal fluid, particularly in the context of solar physics. However, a departure from ideal plasma consideration to non-ideal may lead to a number of modifications in the characteristics of the MHD waves, including its damping too. In what follows, we derive a more general analytical dispersion relation by extending the classical dispersion relation of [Edwin and Roberts, “Wave propagation in a magnetic cylinder,” Sol. Phys. 88, 179–191 (1983)] taking into account the effect of plasma viscosity as a non-ideal term in the existing formulations of the classical model. Consequently, the effects of viscosity on the damping of sausage and kink modes are examined in detail. Multiple trapped body waves of different frequencies exist for both kink and sausage modes in which trapped sausage body wave of comparatively high frequency is damped potentially to generate enough energy to balance the radiative losses of the coronal loop regions. For the coronal loop's plasma parameters, it is found that trapped first radial overtone body wave of sausage type is able to balance the radiative losses of coronal loop structure provided magnetic field strength does not exceed its value of more than 20G.
Single-substrate active metasurface for polarization reconfigurable omnidirectional antenna application
Authors: Yang Huiqiang , Wang Yu , Wang Ping , Yu Xiaoran , Zhou Hongcheng , Yan Zhongming
Published: February 2024

In this paper, a wideband polarization reconfigurable omnidirectional antenna (PROA) based on a single-substrate active metasurface is proposed. By controlling the states of the PIN diodes, the antenna can selectively radiate an omnidirectional linearly polarized wave and an omnidirectional circularly polarized wave. The reflection coefficient, axial ratio (AR), radiation pattern, and gain of the proposed antenna have been analyzed from the perspective of simulation and measurement. The measured results show that the PROA has a wide overlapped bandwidth from 2.87 to 3.67 GHz (relative bandwidth 24.46%). To the authors' best knowledge, this is the first reported wideband PROA based on a single-substrate reconfigurable polarization converter. This study not only offers a novel approach to design PROAs, but also greatly reduces the design complexity of the feed source compared with the traditional design method of PROAs.
Single-photon generation from a neodymium ion in optical fiber at room temperature
Authors: Shimizu Kaito , Inoue Kai , Katsumata Kazutaka , Naruki Ayumu , Sadgrove Mark , Sanaka Kaoru
Published: February 2024

The realization of single-photon generation is important for implementing various quantum information technologies. The use of rare-earth ions in an optical fiber is a promising single-photon generation method due to its ability to operate at room temperature as well as the low cost involved. Neodymium ions are especially interesting because the ions are one of the most commercially affordable rare-earth materials in the current industry. The neodymium ion also has the advantage of having a rich energy level structure, which offers several possible wavelengths for emitted single photons from visible to near-telecommunication wavelengths. In this paper, we experimentally demonstrated single-photon generation using an isolated single neodymium ion in tapered silica fiber at room temperature. Our results have significant implications as a platform for low-cost wavelength-selectable single-photon sources and photonic quantum applications.
Reversed dynamics of bottlebrush polymers with stiff backbone and flexible side chains
Authors: Jakobi Bruno , Bichler Karin J. , Juranyi Fanni , Schneider Gerald J.
Published: February 2024

The segmental dynamics of bottlebrush polymers with a stiff backbone and flexible side chains has been studied. The segmental relaxation time of side chains attached to a flexible backbone follows the same trend as linear polymers, an increase with the increasing molecular weight, but is slowed down compared to their linear counterparts. Theoretical work predicts a reversal of the molecular weight dependence of the relaxation time for stiff backbones. As a model for a stiff-g-flexible system, bottlebrushes with poly(norbornene) backbone and poly(propylene oxide) side chains, PNB-g-PPO, at a uniform grafting density have been synthesized and characterized with quasi-elastic neutron scattering. Indeed, the anticipated reversed dynamics was found. Increasing the side chain length decreases the segmental relaxation time. This indicates the importance of the characteristics of the grafting site beyond a simplified picture of an attached side chain. The mean square displacement shows a similar trend with longer side chains exhibiting a larger displacement.
Chimeras and traveling waves in ensembles of Kuramoto oscillators off the Poisson manifold
Authors: Crnkić Aladin , Jaćimović Vladimir
Published: February 2024

We examine how perturbations off the Poisson manifold affect chimeras and traveling waves (TWs) in Kuramoto models with two sub-populations. Our numerical study is based on simulations on invariant manifolds, which contain von Mises probability distributions. Our study demonstrates that chimeras and TWs off the Poisson manifold always “breathe”, and the effect of breathing is more pronounced further from the Poisson manifold. On the other side, TWs arising in similar models on the sphere always breathe moderately, no matter if the dynamics take place near the Poisson manifold or far away from it.
Hydrodynamic analysis of the upright swimming of seahorse
Authors: Li Xiaohu , Chen Gong , Tang Yanbing , Zhong Jisong
Published: February 2024

The seahorse is the only creature in the ocean that can maintain an upright posture while swimming. This paper mainly discusses the hydrodynamic characteristics and the flow field structure of the seahorse when it swims upright. Using a three-dimensional seahorse model, numerical simulations of self-propelled swimming are conducted by establishing the kinematic equations of its dorsal fin. The focus is on elucidating the effects of the undulation frequency and the inclination angle on swimming performance. The results indicate that a higher undulation frequency of the dorsal fin leads to better acceleration performance, or in other words, greater hydrodynamic forces. The inclination angle of the seahorse's body also directly affects its hydrodynamics and the flow field structure. Unlike other fish that swim horizontally, the seahorse generates forward and upward thrust as the flow field simultaneously spreads backward and downward. Since the upright posture makes the forward thrust much smaller than the upward one, the seahorse has low efficiency in forward propulsion when swimming upright. As the inclination angle decreases, the forward thrust gradually increases and exceeds the upward force, which allows for a rapid improvement in the swimming velocity. The simulation findings of this study are consistent with previous experimental observations.
Limitations and generalizations of the first order kinetics reaction expression for modeling diffusion-driven exchange: Implications on NMR exchange measurements
Authors: Ordinola Alfredo , Özarslan Evren , Bai Ruiliang , Herberthson Magnus
Published: February 2024

The study and modeling of water exchange in complex media using different applications of diffusion and relaxation magnetic resonance (MR) have been of interest in recent years. Most models attempt to describe this process using a first order kinetics expression, which is appropriate to describe chemical exchange; however, it may not be suitable to describe diffusion-driven exchange since it has no direct relationship to diffusion dynamics of water molecules. In this paper, these limitations are addressed through a more general exchange expression that does consider such important properties. This exchange fraction expression features a multi-exponential recovery at short times and a mono-exponential decay at long times, both of which are not captured by the first order kinetics expression. Furthermore, simplified exchange expressions containing partial information of the analyzed system’s diffusion and relaxation processes and geometry are proposed, which can potentially be employed in already established estimation protocols. Finally, exchange fractions estimated from simulated MR data and derived here were compared, showing qualitative similarities but quantitative differences, suggesting that the features of the derived exchange fraction in this paper can be partially recovered by employing an existing estimation framework.
Effects of film cooling injection inclination angle on cooling performance in rotating detonation combustors
Authors: Shen Dawen , Cheng Miao , Rong Guangyao , Sheng Zhaohua , Zhang Yunzhen , Wang Jianping
Published: February 2024

Film cooling is a promising thermal management solution for rotating detonation combustors (RDCs) maturing toward long-duration engineering implementation. Aimed at elucidating the interaction between air coolant and rotating detonation waves (RDWs) and assessing the cooling performance, three-dimensional numerical simulations are conducted on an RDC utilizing four different film cooling injection inclination angles and compared to a case without coolant injection. Increasing injection angles from 30° to 90° results in a broader detachment region and deeper penetration, negatively influencing the cooling performance. A time-averaged method is adopted to evaluate the overall cooling performance, including axial temperature profiles, film protection coverage, RDC film effectiveness, and pattern factor. The results show that the cylindrical cooling hole with a 30° injection angle outperforms others due to enhanced wall attachment of the coolant and reduced interaction with the mainstream hot gas. Consequently, a low injection angle within the manufacturing limits is recommended for practical applications. Furthermore, this study uncovers several phenomena unique to RDCs when introducing film cooling, absent in conventional gas turbines, such as temperature discrepancy between the inner and outer walls, elevated upstream temperature caused by coolant injection, and non-uniform cooling effectiveness between the two sides of the cooling holes. Finally, the interplay between film cooling and RDW is illustrated through temperature and pressure gradient contours.
Calculating high-pressure vibrational frequencies analytically with the extended hydrostatic compression force field approach
Authors: Weiß Rahel , Zeller Felix , Neudecker Tim
Published: February 2024

We report the implementation of the analytical Hessian for the mechanochemical extended hydrostatic compression force field method in the Q-Chem program package. To verify the implementation, the analytical Hessian was compared with finite difference calculations. In addition, we calculated the pressure dependency of the Raman active vibrational modes of methane, ethane, and hydrogen, as well as all IR and Raman active modes of Buckminsterfullerene, and compared the results with experimental and theoretical data. Our implementation paves the way for the analysis of geometric points on a pressure-deformed potential energy surface and provides a straightforward model to calculate the vibrational properties of molecules under high pressure.
Topological rainbow trapping of elastic waves in two-dimensional valley phononic crystal plates
Authors: Lin Jianhua , Qi Yajuan , He Zhaojian , Bi Rengui , Deng Ke
Published: February 2024

Rainbow trapping is a significant strategy for capturing waves of different frequencies at different spatial positions. It offers significant potential for multi-frequency on-chip nanophotonic devices in the era of big data and has attracted much interest recently, and topological rainbow trapping that is immune to disorder has been observed in optics and acoustics. Reported here is the topological rainbow trapping of elastic waves using gradient valley phononic crystal plates (PCPs) with a hexagonal lattice, based on valley edge states that are localized at the boundary between two PCPs with opposite valley topological phases. The gradient valley PCPs are achieved by gradually adjusting the height of the scatterers or the thickness of the PCPs. The topological rainbow trapping of elastic waves is shown by applying vertical vibration to the studied gradient PCPs, which are simple in structure and easily fabricated, providing a good solution for manipulating and trapping elastic waves.
Vibrational state-specific nonadiabatic photodissociation dynamics of OCS+ via A2Π1/2 (ν1 0 ν3) states
Authors: Wang Yaling , Zhao Yunfan , Zhang Ning , Wang Wenxin , Hu Liru , Luo Chang , Yuan Daofu , Zhou Xiaoguo , Parker David H. , Yang Xueming , Wang Xingan
Published: February 2024

The identification and analysis of quantum state-specific effects can significantly deepen our understanding of detailed photodissociation dynamics. Here, we report an experimental investigation on the vibrational state-mediated photodissociation of the OCS+ cation via the A2Π1/2 (ν1 0 ν3) states by using the velocity map ion imaging technique over the photolysis wavelength range of 263–294 nm. It was found that the electronically excited S+ product channel S+(2Du) + CO (X1Σ+) was significantly enhanced when the ν1 and ν3 vibrational modes were excited. Clear deviations in the branching ratios of the electronically excited S+ channel were observed when the vibrational modes ν1 and ν3 were selectively excited. The results reveal that vibrationally excited states play a vital role in influencing the nonadiabatic couplings in the photodissociation process.
Manipulation of magnetic anisotropy of 2D magnetized graphene by ferroelectric In2Se3
Authors: Wang Rui-Qi , Lei Tian-Min , Fang Yue-Wen
Published: February 2024

The capacity to externally manipulate magnetic properties is highly desired from both fundamental and technological perspectives, particularly in the development of magnetoelectronics and spintronics devices. Here, using first-principles calculations, we have demonstrated the ability of controlling the magnetism of magnetized graphene monolayers by interfacing them with a two-dimensional ferroelectric material. When the 3d transition metal (TM) is adsorbed on the graphene monolayer, its magnetization easy axis can be flipped from in-plane to out-of-plane by the ferroelectric polarization reversal of In2Se3, and the magnetocrystalline anisotropy energy (MAE) can be high to −0.692 meV/atom when adopting the Fe atom at bridge site with downward polarization. This may be a universal method since the 3d TM-adsorbed graphene has a very small MAE, which can be easily manipulated by the ferroelectric polarization. As a result, the inherent mechanism is analyzed by the second variation method.
Theoretical approach for the equilibrium scour depth underneath a partially submerged bridge deck
Authors: Koushki Mostafa , Chamani Mohammad R. , Moghim Mohammad N.
Published: February 2024

The destructive implication of pressure-flow scour during flood events is a critical issue for researchers throughout the world. The current paper presents two models to estimate the pressure-flow scour depth underneath a partially submerged bridge deck in the equilibrium phase based on the jet flow theory. An estimate of the submergence distance of the jet flow under the bridge deck is the base point of the first model. The second model uses the phenomenological theory of turbulence where the tangential component of jet velocity is scaled to the velocity of the eddy formed under the bridge deck. This theory has already been used by researchers to estimate the scour depth of the jet flow. Dimensionless parameters are constructed in the theoretical framework of both models. The angle and velocity of the combined jet under the bridge deck and the effective depth underneath the bridge deck have been obtained using the relations presented in the previous research. The application of the presented models is limited to cases where the relative opening height of the bridge deck is greater than 0.25. The derived equations of the current study are calibrated based on the data with sufficient time durations. The results show that both models predict fairly well the maximum pressure-flow scour depth. The values of Nash–Sutcliffe efficiency and relative root mean square errors of the second model predictions are more appropriate, compared to the estimates of the first model and estimates obtained by equations presented in the previous studies.
Generalized system–bath entanglement theorem for Gaussian environments
Authors: Su Yu , Wang Yao , Xu Rui-Xue , Yan YiJing
Published: February 2024

The entanglement between system and bath often plays a pivotal role in complex systems spanning multiple orders of magnitude. A system–bath entanglement theorem was previously established for Gaussian environments in J. Chem. Phys. 152, 034102 (2020) regarding linear response functions. This theorem connects the entangled responses to the local system and bare bath properties. In this work, we generalize it to correlation functions. Key steps in derivations involve using the generalized Langevin dynamics for hybridizing bath modes and the Bogoliubov transformation that maps the original finite-temperature reservoir to an effective zero-temperature vacuum by employing an auxiliary bath. The generalized theorem allows us to evaluate the system–bath entangled correlations and the bath mode correlations in the total composite space, as long as we know the bare-bath statistical properties and obtain the reduced system correlations. To demonstrate the cross-scale entanglements, we utilize the generalized theorem to calculate the solvation free energy of an electron transfer system with intramolecular vibrational modes.
First-principles calculation of lattice distortion, electronic structure, and bonding properties of GeTe-based and PbSe-based high-entropy chalcogenides
Authors: Hasan Sahib , Adhikari Puja , San Saro , Rulis Paul , Ching Wai-Yim
Published: February 2024

The massive amount of wasted heat energy from industry has pushed the development of thermoelectric (TE) materials that directly convert heat into electricity to a new level of concern. Recently, multicomponent alloys such as GeTe-based and PbSe-based high-entropy (HE) chalcogenides have attracted a great deal of attention due to their potential application as TE materials. The nature of the interatomic bonding, lattice distortion (LD), and the electronic structure in this class of materials is not fully understood. Herein, we report a comprehensive computational investigation of nine GeTe-based HE alloys with eight metallic elements (Ag, Pb, Sb, Bi, Cu, Cd, Mn, and Sn) with large supercells of 1080 atoms each; seven PbSe-based HE solid solutions: Pb0.99−ySb0.012SnySe1−2xTexSx (x = 0.1, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, with y = 0) with supercells of 1000 atoms each; and five Pb0.99−ySb0.012SnySe1−2xTexSx (y = 0.05, 0.1, 0.15, 0.2, 0.25 with x = 0.25) solid solutions with supercells of 1000 atoms each. All these HE models are theoretically investigated for the first time. The electronic structure, interatomic bonding, charge transfer, and lattice distortion (LD) are investigated by first-principles calculations based on density functional theory. Multicomponent HE alloys can cause a significant LD, which affects their mechanical, thermal, and TE properties. The calculations for the GeTe-based HE chalcogenides showed that they are semiconductors with a narrow bandgap, except for m8, which has a semi-metallic characteristic, and this makes them good candidates for TE applications. For most of these models, the Fermi level shifts upward and locates deeply in the conduction bands, resulting in the enhancement of the electrical conductivity (σ). The bonding properties showed that most bonds in m5 are more dispersed, indicating highest LD and lower lattice thermal conductivity. For PbSe-based HE solid solutions, the LD calculations showed that the models Pb0.99Sb0.012Se0.5Te0.25S0.25 and Pb0.89Sb0.012Sn0.1Se0.5Te0.25S0.25 have the higher LD, and thus a lower lattice thermal conductivity. Such investigations are in high demand since it enables us to design new HE chalcogenides for TE applications. We use the novel concept of total bond order density as a single quantum mechanical metric to characterize the internal cohesion of these HE alloys and correlate with calculated properties, especially the mechanical properties. This work provides a solid database for HE chalcogenides and a road map for many potential applications. Moreover, the computational procedure we developed can be used to design new HE chalcogenides for specific TE applications.
A Turing test of whether AI chatbots are behaviorally similar to humans
Authors: Mei Qiaozhu , Xie Yutong , Yuan Walter , Jackson Matthew O.
Published: February 2024

We administer a Turing test to AI chatbots. We examine how chatbots behave in a suite of classic behavioral games that are designed to elicit characteristics such as trust, fairness, risk-aversion, cooperation, etc., as well as how they respond to a traditional Big-5 psychological survey that measures personality traits. ChatGPT-4 exhibits behavioral and personality traits that are statistically indistinguishable from a random human from tens of thousands of human subjects from more than 50 countries. Chatbots also modify their behavior based on previous experience and contexts “as if” they were learning from the interactions and change their behavior in response to different framings of the same strategic situation. Their behaviors are often distinct from average and modal human behaviors, in which case they tend to behave on the more altruistic and cooperative end of the distribution. We estimate that they act as if they are maximizing an average of their own and partner’s payoffs.