bluuebunny/crossref_metadata_2025 huggingface dataset:
Graphene nanoribbon FET technology‐based OTA for optimizing fast and energy‐efficient electronics for IoT application: Next‐generation circuit design
Authors: Hashmi Faraz , Nizamuddin M , Farshori Mohammad Aleem , Amin Syed Umar , Khan Zafar Iqbal
Published: October 2024

The Internet of Things (IoT) and portable electronic devices are pivotal in enhancing living standards, with battery efficiency and compact design being critical for these devices. Analogue sensors, integral to advanced artificial intelligence, often necessitate complex real‐time processing and actuation. This study examines the performance of one‐dimensional armchair graphene nanoribbons in graphene nanoribbon field‐effect transistors (GNRFETs). It compares graphene nanoribbon‐based triple cascode operational transconductance amplifiers (GNRFET‐TCOTAs) with conventional CMOS‐based TCOTA. The results reveal substantial enhancements in the GNRFET‐based TCOTAs: the pure GNR‐TCOTA variant shows a remarkable 33.8% increase in DC gain and significant improvements in transconductance, slew rate, and gain‐bandwidth, with enhancements of 8.48, 5.85, and 8.56 times, respectively. Furthermore, the pure GNRFET TCOTA exhibits higher speed, lower energy‐delay product, and settling time compared to Si‐CMOS‐based TCOTA. The study also investigates the impact of critical design parameters on circuit performance. Overall, the research highlights the potential of GNRFETs to optimize TCOTA circuits, offering a path towards more efficient and compact electronic devices, thereby advancing the state of nanoelectronics and supporting the growth of high‐performance IoT systems.
Formation of an effective management team in a Russian medical organization
Authors: Eremina Svetlana , Volkodavova Elena
Published: October 2024

In today’s unstable business environment, there is active development in the medical services market. Competition, as one of the main features of market relations, has a significant impact on medical organizations. The healthcare market has its specific characteristics, as the outcomes of medical organizations’ activities include not only economic but also certain medical effects. The state, in turn, engages in creating and maintaining a competitive environment in the medical services sector through the enforcement of antitrust legislation. Consequently, the management of the organization needs to constantly monitor and maintain competitiveness in the healthcare market to ensure its development and successful functioning. The managerial team of a medical organization plays a crucial role in accomplishing this task. This article explores the problem of forming an effective management team that, despite changes in external environmental factors and the internal state of the medical organization, organizes the work of the team aimed at the successful implementation of both general and key competencies of the organization and its individual specialists, thereby enhancing the competitiveness and stability of the organization in its market segments. Methodological approaches to forming an effective management team are presented. Field research on the stages and results of forming a management team in a Russian medical organization is provided. Directions and recommendations for forming an effective management team are developed. The conclusion emphasizes the necessity of using technologies for forming an effective management team in the practice of Russian medical organizations.
Advancing green entrepreneurship through Industry 4.0 technologies: An analysis of sustainable manufacturing and logistics optimization
Authors: Kulova Ivelina , Nikolova-Alexieva Valentina , Peev Kostadin
Published: October 2024

The study explores the role of Industry 4.0 technologies in fostering green entrepreneurship. It examines the integration of advanced technologies such as artificial intelligence (AI), machine learning, the Industrial Internet of Things (IIoT), and robotics into manufacturing processes. The primary goal of the study is to assess how these technologies can enhance production sustainability, optimize supply chains, and reduce the environmental footprint of logistics. The study employs a qualitative analysis of existing literature, case studies, and statistical data, providing a comprehensive assessment of the impact of these technologies on sustainable manufacturing and green entrepreneurship. The results indicate that Industry 4.0 technologies significantly contribute to sustainable manufacturing by reducing waste and improving energy efficiency. Despite the significant benefits, challenges such as high initial costs for smart equipment, the need for reliable data networks, and increased customer demands hinder the widespread adoption of these technologies. Industry 4.0 technologies offer unprecedented opportunities for enhancing sustainability and supporting green entrepreneurship. Realizing these opportunities requires collaborative efforts among businesses, governments, and stakeholders to ensure balanced economic development and environmental conservation.
Evaluation of the quality of cow’s milk when using a mineral feed additive
Authors: Sufyanova Liliya , Nikolaeva Tatyana , Kislitsyna Nadezhda , Burova Natalya , Savinkova Ekaterina , Dolgorukova Maria , Pegasheva Anastasia , Ivanov Ivan , Hardina Ekaterina , Shuvalova Lyudmila , Nazarova Kristina
Published: October 2024

Optimal cow feeding is the basis for successful dairy production, since feed costs can be up to half the cost of milk. An effective feeding program should achieve several goals: planned milk productivity, increased consumption of dry matter and improved functioning of the rumen microflora. Feed additives that affect the animal’s body play an important role in the diet, which is expressed in an increase in the average daily weight gain, a decrease in conversion rates and an improvement in metabolic processes. However, it is important to remember that additives alone cannot guarantee high productivity or economic benefits of dairy production. The purpose of this study was to study the effect of the multicomponent feed additive “Felucene” on the hygienic quality and safety of cow’s milk. The experiment was carried out in an educational and experimental farm, where, according to the principle of analogues, two groups of dairy cows of 40 heads each were formed. Both groups received the basic diet adopted by the farm, but the first group additionally received “Felucene” at the rate of 5 g per 1 kg of body weight. The analysis of milk composition and productivity was carried out on the 10th, 30th, 60th and 90th days of the study. The use of Felucene led to a 10% increase in dairy productivity of cows and improved milk quality characteristics: the mass fraction of fat increased by 0.09%, protein — by 0.20%, lactose — by 0.18%. The number of fat globules increased by 22%, and the content of the casein fraction increased by 10%. At the same time, the volume of milk corresponding to Class I in rennet fermentation and thermal stability increased by 18% and 17%, respectively.
Green marketing and territorial branding as a regional identity economy element
Authors: Bikmetov Evgeniy , Bogatyreva Marina , Kuznetsova Elena , Ruvenny Igor , Golikov Sergey
Published: October 2024

The aim of the study is to substantiate the idea of developing the identity economy of the socio-economic territorial system on the basis of adapting the classical marketing concept “4P” to territorial marketing taking into account the principles of green marketing. The study is based on the following methodological approaches: institutional and behavioral approaches to the identity economy, the integrated approach and the principle of complementarity, which involves the analysis of the organizational structure of the object, accounting for internal and external interactions, the practice-oriented approach, which involves solving the problems of improving the investment attractiveness, image of territories, the formation of their identity as socio-ecological economic systems. The authors propose to consider territorial marketing as a strategic tool for managing socio-economic and environmental components of the territorial system. Territory identity economy acts as a relationship of market agents who identify their needs and interests with the consumer properties of the given territory. The stages of territorial green marketing strategy are developed. An important direction of marketing activity is branding, which includes the development of communication strategy for forming the image of the territory. The authors substantiate the algorithm of territorial brand formation, which consists of four stages: socio-economic analysis of the territory, development of the brand concept, visual representation of the brand, creation of the brand management structure.
Methods of environmental protection in digital transformation in Russia, Poland and Germany
Authors: Portnova Tatiana
Published: October 2024

The article reveals an actual problem of environmental protection in the framework of the digital transformation of society. On the example of Russia, Poland and Germany as countries from different parts of Europe, the principles and measures that are taken to protect the environment in the context of digital transformation are considered. The research methodology is based on a systematic approach and includes a group of general scientific methods (analysis, synthesis, generalization, systematization); as well as a number of special methods: historiographical analysis of scientific literature on the topic of the study; the method of expert assessments, the method of statistical analysis and verification of research results. An empirical study was based on responses from 75 experts on environmental principles and measures across the European continent. The representative sample was formed on a regional basis and consisted of three expert groups: 25 experts from Russia; 25 experts from Poland and 25 experts from Germany. Based on the results of the study, the author comes to the following conclusions: in Russia, digital transformation is reflected in new forms and methods of state control in the field of environmental protection; Poland is developing a system of enforcement legislation in the field of air, water and raw material quality sensors in the food industry; in Germany, the focus is on public-private partnerships in the field of subsidizing the digitalization of private enterprises to equip environmental protection systems.
Modernization of key production business processes for rapid import substitution of goods, including agriculture
Authors: Zhukov Aleksandr , Ponamareva Svetlana , Kamenskikh Dmitrii , Lyutova Elena , Kartsan Igor
Published: October 2024

The scientific article presents a study on the accelerated import substitution of dual-use goods and technologies by modernizing the main production business processes of enterprises of the defense-industrial complex of the Russian Federation. Accelerated import substitution in the field of dual-use goods and technologies is a transition from dependence on foreign supplies to the production and development of core business processes, own domestic technologies for national defense and security of the country. This helps to reduce national security risks and ensure independence in important areas such as defense and cybersecurity. Modernization of core production business processes and promotion of new technologies contributes to the development of the country’s scientific and technological potential and enhances competitiveness in the global arena. This ensures the growth of the Russian economy, creates new jobs and promotes the potential for innovation. The object of the study is the enterprises of the defense industry complex. The subject of the study - accelerated import substitution of dual-use goods and technologies. The authors connect the prospects of their research with further scientific research in the field of development of dual-use goods and technologies, as well as with the modernization of the main production business processes.
Functional requirements for an intelligent system for monitoring the impact of beaver activity on ecosystems
Authors: Logachev Maxim
Published: October 2024

The consequences of beaver activity affect the condition of natural and anthropogenic systems. The paper presents a brief description of possible consequences of beaver settlement in the natural territory. The monitoring of the number of individuals, the control of the environment and the possibility of forecasting its changes require the development of specialized software tools. The paper presents a description of the main functionalities of such a system and a list of users to whom they are available. These include the detection of beaver habitats, the prediction of environmental changes due to the construction of dams and reservoirs, and the regulation of animal fishing processes. In addition, lists of data are presented, the use of which will make it possible to realize the presented functionalities. The proposed intelligent system will allow forest specialists to monitor the state of natural areas, to specify the list of measures to ensure the preservation of natural and anthropogenic objects. From the point of view of state management, it is possible to create an up-to-date and constantly updated register of beavers and to control their fishing.
Mourir : travail du trépas ou euthanasie ?
Authors: Josserand Serge Alain
Published: October 2024

La loi sur la fin de vie légalisera une exception au commandement du surmoi collectif « tu ne tueras point », fondateur de toute société. Inspirée par une opinion compassionnelle, cette exception appelle le contradictoire, qui procède ici de la connaissance. C’est par le « signal de mort à venir » que le sujet entrera dans la fin de vie, en appelant au « travail du trépas », qui lui permettra de s’effacer psychiquement avant le retrait de la vie, à la faveur de la relation exclusive à un autre. Cette relation peut être soit entravée par les états dissociés de fin de vie, qui font surgir un sentiment d’abandon, et une demande d’euthanasie ; soit récusée par une position philosophique autour du sentiment de dignité.
Restrictive immigration policies and MNE innovation
Authors: Nayak Deepak , Moreira Solon , Mudambi Ram
Published: October 2024

High-skill migrant workers significantly contribute to advanced economies by directly generating knowledge-intensive assets and serving as bridges to knowledge in their origin countries. However, rising populist sentiment has led to increased immigration restrictions in wealthy economies like the U.S. and the European Union. This study examines the impact of the 2004 H-1B visa cap reduction on U.S.-based multinational enterprises (MNEs). We use a sample of 371,856 patents assigned to 707 U.S.-based MNEs. We find that post-shock, MNEs increased the geographic dispersion of their global R&D workforce, rather than replacing foreigners with local American workers. Despite this, the firms experienced a decline in innovation performance, likely due to elevated coordination challenges. Interestingly, sectors relying more on codified knowledge demonstrated increased R&D team dispersion with less impact on innovation. This suggests that the geographic proximity of innovation teams is crucial for tacit knowledge-intensive sectors. These findings highlight the complex consequences of immigration restrictions and suggest boundary conditions on the effectiveness of work-from-anywhere models in knowledge-intensive industries.
Predicting properties of aminated associated polymers as they age
Authors: Liebendorfer Adam
Published: October 2024

Drawing on differential scanning calorimetry, infrared microscopy and small-angle X-ray scattering can help predict shelf life of self-healing adhesives and how to optimize firmness.
Calibration of MAJIS (Moons and Jupiter Imaging Spectrometer): V. Validation with mineral samples and reference materials
Authors: Rodriguez S. , Vincendon M. , Haffoud P. , Langevin Y. , Poulet F. , Quirico E. , Pilorget C. , Filacchione G. , Carter J. , Brunetto R. , Lecomte B. , Guiot P. , Dumesnil C. , Piccioni G.
Published: October 2024

MAJIS (Moons and Jupiter Imaging Spectrometer) is the imaging spectrometer onboard ESA’s JUICE (JUpiter and ICy Moons Explorer) spacecraft that operates in the visible and near/mid-infrared between 0.5 and 5.54 μm. Before the launch of JUICE in April 2023, MAJIS underwent a comprehensive on-ground calibration campaign in between August and September 2021 in the IAS (Institut d’Astrophysique Spatiale, Université Paris-Saclay) calibration facilities. Among all the operations, calibration sequences using a set of natural mineral samples and synthetic reference materials were acquired in order to characterize MAJIS performances under conditions assumed to be close to certain future observation configurations. Here, we analyze these calibration measurements using comparison with laboratory reference spectra to quantify MAJIS spectral and spatial performances while observing these solid surfaces. We first assess the MAJIS absolute spectral calibration of the visible and near-infrared channel covering half of the wavelength range. We then quantify spectral performances in terms of global spectral slopes, band detection, band shape, and depth retrievals, over most of the spectral range using six mineral samples. We conclude that for most configurations, the MAJIS instrument demonstrates excellent spectral performances compliant with the requirements. MAJIS can, however, be affected by stray light contributions, notably for wavelengths lower than about 1.2 μm, and some performances of the instrument may then be significantly impacted depending on viewing conditions. In particular, we have identified cases of spectral contrast reduction up to 40%, absolute spectral shifts up to 2–3 nm, and spectral smile variability by +/1 nm. Finally, we used the MAJIS internal scanning mirror to test its ability to construct hyperspectral images of a few samples: we present the first band depth maps derived with MAJIS while observing a serpentine/carbonate sample, as well as an evaluation of MAJIS spatial point spread function. Overall, the analysis of MAJIS behavior while observing samples confirms most MAJIS expected performance requirements, while revealing subtle spectral perturbations that may be related to stray light and viewing conditions. These differences will be further investigated in-flight during the cruise, with a solar reflected target such as the Moon, as well as Jupiter before the JUICE orbital insertion.
Strong evidence for universality in homogeneous compressible turbulence
Authors: Panickacheril John John , Donzis Diego A.
Published: October 2024

Quantifying the degree of universality in compressible turbulence is challenging due to the existence of different modes and their complex interactions. For a restricted family of flows, Donzis and John [Phys. Rev. Fluids 5, 084609 (2020)] showed that universal behavior is indeed observed in compressible turbulence if the ratio of dilatational to solenoidal root mean square (rms) velocities (δ=u′d/u′s) is incorporated as a scaling parameter along with the traditional turbulent Mach number (Mt=u′/〈c〉, where u′ is the rms velocity and 〈c〉 is the mean speed of sound). In this paper, we argue for the generality of those results by analyzing a wide range of compressible turbulent flows spanning a variety of flow configurations and setups to assess the degree of universal behavior. These include, among others, reacting flows, flows with solenoidal, thermal, and dilatational forcing, and flows with mean shear and bulk viscosity. We also performed new direct numerical simulations, which include turbulence in situations where vibrational modes of constitutive molecules are not in thermal equilibrium. Collectively, we offer the largest comparison across studies in the literature to date. We find that despite the wide range of forcing conditions and physical processes, universality holds across all these turbulent flows to a very satisfactory degree when both δ and Mt are considered as intrinsic compressibility parameters. The statistics investigated here—single-point statistics up to order four—are chosen such that they represent different ranges across the spectrum of dynamically relevant turbulence scales. We discuss the applicability of the purposed universal behavior for other key statistics in these turbulent flows, including two-point statistics and inhomogeneity effects, and the perspective it opens for modeling them.
MightyLev: An acoustic levitator for high-temperature containerless processing of medium- to high-density materials
Authors: Drewitt James W. E. , Emmens Barnaby , Kong Zhe-Hui , Drinkwater Bruce W. , Barnes Adrian C.
Published: October 2024

“MightyLev,” a new multi-emitter ultrasonic acoustic levitation device capable of extremely stable levitation of materials of density up to at least 11.3 g cm−3, is described. The exceptional stability of medium- to high-density samples levitated in MightyLev makes the device highly suitable for chemical and structural analysis using micro-focused spectroscopic and x-ray scattering techniques. In combination with mid-infrared laser heating, MightyLev is capable of levitating metallic and oxide materials during high-temperature cycling and melting above 1500 K. Instabilities in particle confinement during heating were investigated by directly visualizing the acoustic field using schlieren imaging. The results reveal jets of hot-air directed along the anti-nodes of the acoustic field. The reaction force on the sample from the jet, coupled with the restoring force of the acoustic trap, generates a parametric lateral oscillation of the sample. This result provides valuable insight for future optimization and wider application of acoustic levitation for high-temperature containerless material processing.
Thermonuclear performance variability near ignition at the National Ignition Facility
Authors: Divol L. , Pak A. , Bachmann B. , Baker K. L. , Baxamusa S. , Biener J. , Bionta R. , Braun T. , Casey D. T. , Choate C. , Clark D. S. , Dewald E. , Döppner T. , Fittinghoff D. N. , Hahn K. D. , Hilsabeck T. J. , Hohenberger M. , Holder J. P. , Hurricane O. A. , Izumi N. , Kerr S. , Khan S. F. , Kozioziemski B. , Kritcher A. L. , MacGowan B. J. , MacPhee A. G. , Marinak M. M. , Marley E. V. , Moore A. , Nikroo A. , Nora R. C. , Ralph J. E. , Rubery M. S. , Ruof N. , Schlossberg D. J. , Schroeder C. , Sepke S. M. , Shin S. J. , Springer P. T. , Stoupin S. , Tommasini R. , Trosseille C. , Volegov P. , Weber C. , Young C. V. , Mackinnon A. J. , Moody J. D. , Smalyuk V. A. , Landen O. L. , Stadermann M. , Town R. P. J. , Aghaian L. , Alfonso N. , Allen A. , Clark K. , Crippen J. , Havre M. , Huang H. , Hund J. F. , Kong C. , Lapa P. N. , Mauldin M. , Pajoom S. , Ratledge M. , Sequoia K. , Vakki W. , Fehrenbach T. , Wild C. , Zylstra A. B. , Birge N. W. , Freeman M. S. , Geppert-Kleinrath V. , Geppert-Kleinrath H. , Kim Y. , Lamb K. , Meaney K. D. , Wilde C. H.
Published: October 2024

We describe our current understanding of the variability and degradation mechanisms observed through a series of five indirectly driven inertial fusion implosions fielded at the National Ignition Facility in the fall of 2021, four of which attempted to reproduce the first experiment to achieve Lawson's criterion for ignition with a thermonuclear yield of 1.35 MJ on August 8, 2021. A large number of absolutely calibrated (imaging, time-resolved, and spectrally resolved) x-ray and neutron diagnostics are fielded on the NIF along multiple lines of sight for each experiment. This allows for a reconstruction of the DT fuel and ablator mix injected into the hotspot around peak burn. We show that nuclear yield variations are well reproduced by numerical modeling when the measured low mode asymmetries and mix mass are included. Furthermore, these observed perturbations during burn are linked to small variations in laser delivery and capsule defects. Stringent specifications are then set to achieve robust ignition with the implosion design studied in this paper.
Hidden data recovery using reservoir computing: Adaptive network model and experimental brain signals
Authors: Badarin Artem , Andreev Andrey , Klinshov Vladimir , Antipov Vladimir , Hramov Alexander E.
Published: October 2024

The problem of hidden data recovery is crucial in various scientific and technological fields, particularly in neurophysiology, where experimental data can often be incomplete or corrupted. We investigate the application of reservoir computing (RC) to recover hidden data from both model Kuramoto network system and real neurophysiological signals (EEG). Using an adaptive network of Kuramoto phase oscillators, we generated and analyzed macroscopic signals to understand the efficiency of RC in hidden signal recovery compared to linear regression (LR). Our findings indicate that RC significantly outperforms LR, especially in scenarios with reduced signal information. Furthermore, when applied to real EEG data, RC achieved more accurate signal reconstruction than traditional spline interpolation methods. These results underscore RC’s potential for enhancing data recovery in neurophysiological studies, offering a robust solution to improve data integrity and reliability, which is essential for accurate scientific analysis and interpretation.
Identification and classification of clusters of dipolar colloids in an external field
Authors: Skipper Katherine , Moore Fergus J. , Royall C. Patrick
Published: October 2024

Colloids can acquire a dipolar interaction in the presence of an external AC electric field. At high field strength, the particles form strings in the field direction. However, at weaker field strength, competition with isotropic interactions is expected. One means to investigate this interplay between dipolar and isotropic interactions is to consider clusters of such particles. Therefore, we have identified, using the GMIN basin-hopping tool, a rich library of lowest energy clusters of a dipolar colloidal system, where the dipole orientation is fixed to lie along the z axis and the dipole strength is varied for m-membered clusters of 7 ≤ m ≤ 13. In the regime where the isotropic and dipolar interactions are comparable, we find elongated polytetrahedral, octahedral, and spiral clusters as well as a set of non-rigid clusters, which emerge close to the transition to strings. We further implement a search algorithm that identifies these minimum energy clusters in bulk systems using the topological cluster classification [J. Chem. Phys. 139 234506 (2013)]. We demonstrate this methodology with computer simulations, which show instances of these clusters as a function of dipole strength.
Numerical and theoretical modeling of water droplet impact on hydrophilic and superhydrophobic cones
Authors: Yang Wen , Liu Chuan-Yang , Zhang Yun-Bo , Ruan Jie , Deng Pei-Yan
Published: October 2024

The phenomenon of droplet impingement on solid surfaces is prevalent in various natural and industrial contexts. Research on impact dynamics on conical surfaces keeps emerging, with superhydrophobic cones receiving more attention than hydrophilic ones. This study systematically investigates water droplet impact dynamics on both hydrophilic and superhydrophobic cones using a two-phase numerical solver under different Weber numbers (We) and cone angles (φ). Three distinct phases are identified in the We–φ map to describe the different outcomes on each type of cones. Generally, deposition occurs ultimately on hydrophilic cones, whereas rebounding is observed on superhydrophobic ones. The maximum spreading area βAmax on hydrophilic cones depends only slightly on φ but consistently increases with We, following a scaling law of We0.5 at higher We. In contrast, on superhydrophobic cones, βAmax increases significantly with both We and φ, and the exponent in the scaling laws of βAmax with respect to We increases notably as φ increases. Three characteristic times are defined to describe important motion states on both types of cones. Corresponding scaling laws for each time with We are established. Two theoretical models are developed to predict the maximum spreading position for droplets on hydrophilic cones and the rebound position on superhydrophobic cones, respectively. Gravitational potential energy is included in the energy budget for both models, and an auxiliary viscous dissipation due to spontaneous spreading is accounted for the hydrophilic case. Satisfactory agreement between the theoretical and numerical results is achieved.
Computational screening of single-atom transition metals on boron-rich boron nitride nanosheets for efficient hydrogen evolution catalysis in all pH range
Authors: Wei Yuhua , Gao Feng , Yuan Jiantao , Xie Hao , Xiao Duo , Zhang Hui , Wang Yin , Ren Wei
Published: October 2024

Low-cost and high-efficiency catalysts are of crucial importance for the electrocatalytic hydrogen evolution reaction (HER). Two-dimensional (2D) boron nitride (B–N) compounds formed by the combination of boron and nitrogen atoms of group III and V elements are promising candidates for electrocatalytic HER due to their significant electronic properties. Hence, an electrocatalyst is computer-aided designed with isolated single atoms of 3d, 4d, and 5d transition metals supported on 2D B–N (B2N, B5N3, and B7N5) monolayers to fabricate single-atom catalysts (SACs) with an excellent HER performance. Moreover, pH modulations are considered to improve the HER activity theoretically based on first-principles calculation. Our results indicate that B–N compounds surface doping with transition metal atoms can effectively enhance the HER catalytic performance over a wide range of pH. Among all SACs studied, Co-, Ti-, V-, Nb-, Ru-, Tc-, Zr-, and Os-embedded B2N, Sc-, Cr-, Mn-, Ti-, and Y-embedded B5N3, and Sc- and Mn-embedded B7N5 have excellent catalytic activity under acidic conditions, while Mo-, Ir-, Re-, Ta-, and W-embedded B2N and Ti- and Fe-embedded B7N5 show high catalytic activity under alkaline conditions. Interestingly, Hf@B2N and V@B5N3 systems exhibit promising catalytic activity under acidic, neutral, and alkaline conditions. Our work offers cost-effective candidates with a wide pH range HER performance for exploring ideal electrocatalysts.
Influence of tip air injection on the unsteady blade force under circumferential pressure distortion
Authors: Li Jichao , Peng Feng , Zhang Xiaoyu , Wang Wentao , Fan Boning , Deng Yuyang
Published: October 2024

In order to further understand the impact of tip air injection on compressor stability under circumferential pressure distortion, a series of experimental studies on tip air injection under uniform and circumferential distortion were conducted on a low-speed single rotor axial flow compressor. The unsteady measurements were carried out by use of microsensors and strain gauges bonded on the rotor blade surfaces, and a collection of dynamic pressure sensors installed on the casing wall. Results indicate that with the increase in the injected momentum ratio, the load at the leading edge near the rotor blade tip obviously decreases, thereby delaying the stall. By comparing the pressure distribution on the rotor blade surface under different injected momentum ratios, tip air injection can effectively suppress flow separation at the blade tip to enhance flow capability. In addition, it can also weaken the fluctuation of tip leakage flow and reduce the dynamic stress similar to natural vibration near the blade root both in stationary and rotating coordinate systems. Under the condition of inlet circumferential distortion, tip air injection can significantly reduce the load at the distorted region and suppress the low-frequency disturbances measured on the rotor blade surface caused by inlet distortion. In addition, the dynamic stress near the blade root can also be effectively reduced by tip air injection. It implies that tip air injection can both extend the stall margin and reduce blade vibration when suffering from circumferential distortion; thus, the compressor can safely operate.
Multi-stage electroporation dynamics induced by ionization wave–substrate interaction in cold plasma jet
Authors: Chen Kai , Wu Feiyu , Mao Yilong , Wang JiaLei , Liang Runze , Lei Yuan , Chen Yue , Li Lei , Yao Chenguo
Published: October 2024

The reactive species-independent nature of cold plasma's electric field is pivotal in biomedical applications. This work proposes to connect the plasma fluid model and the asymptotic Smoluchowski model for electroporation, providing a unified framework to investigate the evolution of the electric field in the biological substrate and the multi-stage electroporation response of the human cell. Two common substrates with distinct dielectric properties, namely, the cultivation medium and epidermis, are selected to report three stages of ionization wave (IW)–substrate interaction. The three-stage streamer discharge dynamics (restrike, axial-radial transition, and radial expansion of IW) induce three-stage cell electroporation dynamics (slow charging, fast charging, and electroporation), though the two processes are asynchronous. Specifically, the inner membrane covered the cell nucleus with ultra-short charging time that undergoes only the first two discharge stages in both substrates. Whether the cell membrane is exposed to the third stage of discharge depends on the permittivity of the substrate. The asynchrony can be attributed to the difference in the charging time of the cell membranes and substrates affected by the substrate permittivity. The presented model can provide quantitative insights into the cell electroporation induced by the IW–substrate interaction and theoretical guidance for plasma biomedical applications.
DC voltage switching-based octuple-electrode microdevice for cell rotation and area-specific membrane capacitance measurement
Authors: Huang Liang , Wang Tan , Qian Jingui , Zhang Jin , Xia Haojie
Published: October 2024

Single-cell electrorotation plays an important role in the field of single-cell imaging and electric parameter measurement. However, reported cell rotation technology often adopts a quadruple-electrode structure and is excited by an AC signal. The distribution of electric field strength in the enclosed area is not uniform, and the rotation speed of the cells is related to the location in the area, so it is difficult to achieve uniformity of electric field distribution and the stationarity of rotation. This work proposes a DC voltage switching-based octuple-electrode microdevice for cell rotation and area-specific membrane capacitance measurements. This design can switch the DC voltages on each electrode periodically to produce a uniformly distributed rotating electric field. The rotation direction of the electric field can be realized by simply controlling the switching order of the analog switches. According to the theoretical single-cell model, the area-specific membrane capacitance of cells are determined through rotation movements. Simultaneously, based on simulation results, the rotation area is normalized to enhance the accuracy of the measuring electrical parameters. This study demonstrates the potential application of the proposed octuple-electrode DC voltage-based electro-rotation device for rapid, convenient, and cost-effective manipulation and electrical parameter measurement of single cells.
Full-f gyrokinetic simulations of hydrogen isotope mixing in tokamak plasmas
Authors: Idomura Y.
Published: October 2024

Hydrogen isotope mixing phenomena in tokamak plasmas are analyzed using global full-f gyrokinetic simulations. Model plasma parameters are chosen based on hydrogen isotope pellet experiments on JET, in which fast hydrogen isotope mixing in the timescale of the energy confinement time τE occurred after injecting deuterium (D) pellets into hydrogen (H) plasmas. Two numerical experiments are conducted using plasma profiles before and after the pellet injection. In both cases, turbulent fluctuations in the plasma core are characterized by ion temperature gradient driven turbulence. In the former case, the density profile of bulk H ions is kept in a quasi-steady state, and the particle confinement time of bulk H ions τH is an order of magnitude longer than τE. In the latter case, the density profiles of bulk H ions and pellet D ions show transient relaxation in the timescale of τE, and both τH and the timescale of particle pinch τD become comparable to τE, indicating the fast hydrogen isotope mixing. In the toroidal angular momentum balance, it is found that the enhanced ion particle transport leading to the fast hydrogen isotope mixing is driven by the toroidal field stress.
Characteristics of shear stress fluctuations in polymer solutions and their relation to turbulent structures in channel flows
Authors: Wang Yu , Tsuji Yoshiyuki
Published: October 2024

In this study, the wall shear stress in the channel flow of polyacrylamide polymers was investigated through electrochemical experiments, and the effects of the polymer concentration were evaluated at different Reynolds numbers. The objective was to explore the relationship between the changes in the drag reduction and near-wall turbulence structure induced by the polymer. The experiments were conducted using polymer concentrations of 0, 20, 50, 100, and 150 ppm, and a drag reduction of approximately 23% was achieved at a bulk Reynolds number of Reb = 18 750. In the electrochemical method, the working electrode was arranged spanwise, and simultaneous measurements were performed for eight electrodes to discuss the scale of the near-wall low-speed streaks and burst events. A comprehensive analysis of the correlation of the wall shear stress in the streamwise direction and the cross-spectrum of two points in the spanwise direction revealed that large streamwise and spanwise scales of near-wall low-speed streaks were generated at high polymer concentrations. Furthermore, the results obtained using the variable interval time averaging technique indicated that polymer incorporation suppressed the wall shear stress fluctuations and weakened both the intensity and frequency of the bursting events.
Hamiltonian formulation of X-point collapse in an extended magnetohydrodynamics framework
Authors: Abdelhamid Hamdi M. , Lingam Manasvi
Published: October 2024

The study of X-point collapse in magnetic reconnection has witnessed extensive research in the context of space and laboratory plasmas. In this paper, a recently derived mathematical formulation of X-point collapse applicable in the regime of extended magnetohydrodynamics is shown to possess a noncanonical Hamiltonian structure composed of five dynamical variables inherited from its parent model. The Hamiltonian and the noncanonical Poisson brackets are both derived, and the latter is shown to obey the requisite properties of antisymmetry and the Jacobi identity (an explicit proof of the latter is provided). In addition, the governing equations for the Casimir invariants are presented, and one such solution is furnished. The above features can be harnessed and expanded in future work, such as developing structure-preserving integrators for this dynamical system.
Current-driven mechanical motion of double stranded DNA results in structural instabilities and chiral-induced-spin-selectivity of electron transport
Authors: Davis Nicholas S. , Lawn Julian A. , Preston Riley J. , Kosov Daniel S.
Published: October 2024

Chiral-induced-spin-selectivity of electron transport and its interplay with DNA’s mechanical motion are explored in a double stranded DNA helix with spin–orbit-coupling. The mechanical degree of freedom is treated as a stochastic classical variable experiencing fluctuations and dissipation induced by the environment as well as force exerted by nonequilibrium, current-carrying electrons. Electronic degrees of freedom are described quantum mechanically using nonequilibrium Green’s functions. Nonequilibrium Green’s functions are computed along the trajectory for the classical variable taking into account dynamical, velocity dependent corrections. This mixed quantum-classical approach enables calculations of time-dependent spin-resolved currents. We showed that the electronic force may significantly modify the classical potential, which, at sufficient voltage, creates a bistable potential with a considerable effect on electronic transport. The DNA’s mechanical motion has a profound effect on spin transport; it results in chiral-induced spin selectivity, increasing spin polarization of the current by 9% and also resulting in temperature-dependent current voltage characteristics. We demonstrate that the current noise measurement provides an accessible experimental means to monitor the emergence of mechanical instability in DNA motion. The spin resolved current noise also provides important dynamical information about the interplay between vibrational and spin degrees of freedom in DNA.
Onset of Darcy–Brinkman convection with thermal anisotropy in an inclined porous layer
Authors: Mourya Pappu Kumar , Kumar Gautam
Published: October 2024

In this article, we study the linear instability and the nonlinear stability (through energy functional) analyses of thermal convection in an inclined Darcy–Brinkman porous layer considering uniformly heated horizontal rigid, impermeable walls from below and above. The effects of a uniform internal heat source and anisotropy in effective thermal diffusivity on heat transfer are also considered. Heating the porous layer from below yields the temperature gradient, influencing the buoyancy and making the convection happen. This temperature gradient also impacts the base state. The basic solution for velocity incorporates both hyperbolic and polynomial functions, significantly increasing the complexity of linear and nonlinear analyses. The Chebyshev-tau method, together with the QZ algorithm, is used to solve the linear and nonlinear perturbed system of equations numerically. The region of subcritical instability is obtained by comparing the linear and nonlinear thresholds for the longitudinal and transverse rolls, respectively. We found that perturbations for longitudinal and transverse rolls do not grow after inclination is more than 30.3° and 31.3°, respectively. It has been noted that in transverse roll scenarios, the flow becomes stabilized when the inclination angle, ϕ, is equal to or exceeds 60°, where ϕ plays a leading role in surpassing the impact of internal heating. However, when the inclination angle is ϕ<60°, then internal heating dominates and destabilizes the flow. For the longitudinal rolls, the internal heating dominates the whole range of ϕ, destabilizing the system. Furthermore, it can be seen that the Darcy number (Da) and the anisotropic thermal diffusivity (ξ) delay the onset of convection.
Equation of state of the relativistic electron–positron–photon plasma at arbitrary temperature and degeneracy
Authors: Faussurier Gérald
Published: October 2024

We consider the plasma made of relativistic electrons and positrons in thermodynamic equilibrium with photons at arbitrary temperature and degeneracy. We establish various thermodynamic identities as a function of the electron and positron chemical potentials and temperature. The high-temperature regime in which the electrons and positrons are ultrarelativistic is recovered. The excess of electrons with respect to positrons or the excess of positrons with respect to electrons depends on the thermodynamic conditions. Doing so, we go beyond what is usually found in the literature where only the high temperature regime is usually tackled.
Comparative study of analytical models with linear and quadratic pressure drop conditions on a perforated plate in water waves
Authors: Chen Qunbin , Cui Junnan , Feng Xingya , Liu Yuming , Chen Jianfei
Published: October 2024

Proper pressure drop conditions are essential in predicting hydrodynamic performance of perforated structures in the framework of a potential flow theory. In this study, we investigate water waves passing through a perforated plate with various pressure drop models to examine how pressure drop conditions affect the hydrodynamic performance of perforated structures. We derive the analytical solutions of waves across the perforated plate by adopting three commonly pressure drop conditions, including one linear pressure drop condition (LPDC), and two quadratic pressure drop conditions (QPDCs). A series of laboratory experiments are conducted to validate the present theoretical results. We compare the hydrodynamic performance between the experimental data and the theoretical solutions with the three different pressure drop models, typically for wave reflection coefficients, dynamic pressures, and velocity fields measured by the technique of particle image velocimetry in the experiments. It is found that the existing pressure drop models can predict well wave reflection coefficients, dynamic pressure, and velocity profiles at certain conditions. However, the linear wave solutions associated with LPDC or QPDCs generally underpredict the amplitude of particle velocity near the free surface on the perforated plate. This underestimation increases largely as the wave steepness increases. The LPDC performance relies much on the selection of empirical coefficients. For the QPDCs, the analytical models show deviated results from the experimental data for wave reflection coefficients when the wave steepness is relatively low.
Development of a high-precision long trace profiler utilizing shear measurements
Authors: Cui Xiaowen , Wu Ming , Dong Han , Qin Xiaobo , Yang Fugui , Zhang Xiaowei , Li Ming , Sheng Weifan
Published: October 2024

Compensating for the pitch error in the scanning movement is a fundamental issue when conducting large-scale surface shape measurements with deflectometric profilers. This paper presents a new long trace profiler employing a shearing measurement technique. In this setup, the optical head and the mirror under test are mounted on two independent parallel movable air-bearing carriages to enable shearing and scanning movements separately. The distance between the optical head and the tested mirror remains fixed, effectively minimizing the influence of system errors resulting from imperfections in optical devices. Simulation studies show that the double shear measurement method with a low-spatial-frequency filtering process can effectively mitigate high-frequency angular measurement errors introduced by the instability of the air-bearing stage. Experimental tests conducted on flat mirrors demonstrated a precision of less than 50 nrad rms, thereby confirming the robustness of the system.
A coupled fractal model for predicting the relative permeability of rocks considering both irreducible fluid saturation and stress effects
Authors: Zhao Mingkai , Kong Desen , Shi Jian , Teng Sen
Published: October 2024

The relative permeability of rocks is an essential parameter for evaluating two-phase flow characteristics and plays an important role in engineering fields such as resource exploitation. To this end, a mathematical model for predicting relative permeability was first developed based on an equivalent capillary model and fractal theory. The proposed model considers the irreducible fluid saturation under stress and quantifies the influence of the pore structure characteristics on the relative permeability. This model was then compared with relevant experimental data and existing theoretical expressions to verify its validity. Finally, the factors affecting the two-phase seepage characteristics were discussed. The results show that the irreducible fluid saturation is intimately connected to the fractal dimensions, pore size, fluid viscosity, pressure drop gradient, and elastic modulus. Fluid properties and pore structure characteristics are the main factors affecting relative permeability. The wetting phase relative permeability is more sensitive to pore structure and irreducible fluids. Increased effective stress increases irreducible fluid saturation, reduces two-phase flow capacity, and significantly decreases the relative permeability of wetting phase fluids. Increased elastic modulus and Poisson's ratio decrease the irreducible fluid content under stress and increase the permeability.