bluuebunny/crossref_metadata_2025 huggingface dataset:
Mitigation carbon emissions by microalgae: Assessing the viability of culture Arthrospira platensis grown on high CO2 concentrations
Authors: Chernova Nadezhda , Kiseleva Sophia , Chunzhuk Elizaveta , Grigorenko Anatoliy , Vlaskin Mikhail
Published: August 2023

In this work, experimentally evaluated the viability of a consortium microalgae Arthrospira platensis rsemsu P Bios with heterotrophic bacteria when cultivated in a gas-air mixture with high concentrations of CO2 (from 0.04 to 9%). A laboratory setup was created to test the viability of microalgae strains at high concentrations of CO2. The experiments were carried out using 12 photobioreactors with a culture medium volume of 4 L each, placed in a gas chamber, which makes it possible to create elevated CO2 concentrations in the gas-air medium. The maximum growth rate of biomass of microalgae A. platensis is 170 mg/(l per day), the maximum absolute increase in biomass for 12 days is 1540 mg/l. The relatively low growth rate and absolute increase in the biomass of A. platensis at all concentrations of CO2 in the gas-air mixture may indicate that this culture requires a longer laboratory adaptation to high concentrations of CO2. The high cell viability found in all experiments by cytochemical staining of cells with methylene blue indicates the acquired tolerance of the culture to elevated CO2 concentrations (3–9%). However, after 12 days of the experiment with 9% CO2, morphometric signs of cell suppression are detected, which is expressed in deviations of the cell shape from normal, elongation (lack of division) and an increase in the number of dead cells. Quantitative characteristics of the microalgae consortium viability have been obtained.
Ecological and economic significance of the Middle Don sand arenas
Authors: Kulik Alexey , Vlasenko Marina
Published: August 2023

The research purpose is a comprehensive assessment of the Middle part of the Don river sand massifs soil and hydrological conditions. The research objects are the sandy massifs of the Middle Don on an area of 527 thousand hectares. The sand arenas water balance dynamics for the period from November to March and for the period from April to October has been revealed. It has been established that atmospheric precipitation is the main source of river water supply. The basis of river systems flood filling are clay soils that form an intra-soil runoff. The low water period level is supported by sandy soils. A decrease in the density of plant formations contributes to an increase in groundwater supply. The total underground runoff reaches 599 million m3 from the sandy massifs of the Middle Don. The volume and dynamics of the moisture movement in the soil depend on the system of sandy areas use. Therefore, the load on sandy arenas should be regulated. Pasture farming should remain the dominant form of sand use. An effective method of sandy arenas afforestation is the planting of pine plantations according to the savanna type.
Seasonal comparative geochemistry of ultra trace elements content in agricultural soils near Lake Sevan
Authors: Sukiasyan Astghik , Kalantaryan Marine , Ledashcheva Tatiana , Kirakosyan Armen
Published: August 2023

The contamination status of the soils from Hrazdan, Gavar, and Martuni regions has been investigated by comparing UTEs indicators with % humus and pH in soil samples during different seasonal intervals steppe chernozem soil type was studied. It was found that the maximum of % humus exceeded the minimum % almost twice in the soil samples. The soil samples were found to be neutral in terms of pH character. The results for the Hrazdan region show on 10% increase of barium content and 70% decrease of arsenic content in soil samples taken in winter 2022 compared to the whole period studied. For spring 2022, the same variant shows on 27% increase of chromium and 19% of vanadium. The change in nickel content was within the average for the whole period. The results for the Gavar region show an average dynamic increase of 22% of barium content in soil samples from autumn 2021 to spring 2022 compared to the whole sampling period. The change of the content other UTEs was within the average value for the whole sampling period. Alternating decreases (winter and summer 2022) and increases (autumn 2021 and spring 2022) of the barium content were observed in the soil samples from the Martuni region. The change of UTEs content in the soil was within the average value for the whole period sampled. The increased value of the Zc coefficient in autumn was found to be typical for all investigated regions, although the values vary. The highest value of the coefficient is observed in the Hrazdan region and the lowest value in the Martuni region.
Application of technological innovations in the tourism industry
Authors: Ilieva Lyubka , Petrova Mariana , Todorova Lyubomira
Published: August 2023

In the conditions of digitization and ecological transformation of industry and society, studying the opportunities to apply technological innovations and their impact on the tourism sector has become a research topic. The directions of tourism business innovations are explored and the role of technological innovations in adapting the tourism sector to the processes of transformation and digitalization of society is outlined by conducting a systematic analysis. The aim of this study is to identify the different approaches to tourism product innovation, clarify the scope of technological innovation and to present the possibilities of their application in the tourism sector. As a result of the study the scope of technological innovations in the tourism sector is outlined and guidelines for their application are proposed in order to diversify the tourist product and optimize tourism business activities.
The role of locally produced bio products in the development of agritourism
Authors: Tsetskhladze Murman , Sulaberidze Salome
Published: August 2023

One of the preconditions for the development of agritourism is the cultivation and production of natural agricultural products. It is for this purpose that we studied the specificity of the interdependency between tourism and agriculture on the example of Guria, one of the regions of Georgia. The potential and development perspectives of all three municipalities of the region (Ozurgeti, Chokhat’auri, and Lanchkhuti) are discussed in the article. The study is focused on the main elements of agritourism, on the local possibilities of food production, and on its natural character. The results of the research prove that there is a great interest among tourists in this activity, which is due to the purchase and tasting of quality and safe food and their participation in its production. Besides that, hindering factors are identified: in the first place, it is the ignoring of food safety rules, the failure of the infrastructure, and insufficient financial resources.
Partnership consensus in triple helix pathways: A challenge for sustainable higher education
Authors: Astuty Eriana
Published: August 2023

The study’s purposes are (i) to determine the gender role in the relationship between partnership consensus with the lecturer’s attributes and (ii) to test Etzkowitz’s partnership pathways in determining the role of consensus in mediating the influence of an institution’s sustainable entrepreneurial culture (ISEC) on innovation. This study confirmed that the partnership consensus has no relationship with the education level of male lecturers, while the functional position has one. In contrast, a partnership consensus for female lecturers has no significant relationship with the educational level and functional position. The partnership consensus was able to mediate ISEC’s influence in the Etzkowitz partnership path towards the emergence of innovation to 53% from 30% directly. The quadruple helix in Indonesia was decomposed into a triple helix with a university-government-community and university-industry-community partnership pattern. The conclusions are lecturers’ partnership consensus has no relationship with internal factors, such as education level or functional position, but rather because of the institutional culture that supports increasing innovation capability, namely ISEC. Internal and external partnership consensus triggers innovation significantly. These findings are helpful for higher education (HE) policymakers, where gender equality is crucial to formulate in partnership. Furthermore, HE must build an ISEC to trigger the innovations as a manifestation of HE’s contribution to sustainable regional socio-economic development.
Challenges and barriers in transition to circular economy business models
Authors: Gechbaia Badri , Maisuradze Teona , Paresashvili Nino , Goletiani Ketevan , Gvarishvili Levan
Published: August 2023

Circular Economy (EC) is a term that has not been studied fully yet and is attracting the growing interest of scholars. It is vital for our planet and each of our lives to take care of EC principles. In this process, the business sector plays a leading role. This process is challenging and requires understanding circular economy principles first, after analyzing linear business models and comparing them to the CBM (Circular Economy Business Model). Based on these, it will be easier for businesses to adopt any of them. The aim of the paper is to discuss these and give recommendations based on the literature, research papers, and publications available at this moment. Key Findings: The barriers to moving from BM to CBM are still strong, but business behavior shows that there are already some signs of a circular economy, which can be considered an important step for the planet and people’s lives; recommendations are given on how to help businesses to overcome obstacles on this difficult path.
Measuring indicators of a circular economy and sustainable development in European Union countries
Authors: Buryk Zoriana , Kozhyna Alla , Doroshenko Hanna , Shumkova Viktoriia , Vlasiuk Yelizaveta
Published: August 2023

The study analyses the principles and conditions of the functioning of the circular economy and identifies factors contributing to its successful implementation. Specialized general indicators, such as the Sustainable Development Index and the Innovation Index, are used in the study to assess the adoption of innovative and eco-friendly technologies. The data on circular economy development, innovation, and sustainable development in EU countries are analysed. It enables a comparison of their development levels and circular economy implementation. The research findings demonstrate that countries actively implementing environmental requirements and standards in social production, such as Sweden and Finland, or economically advanced countries like France, Germany, and the Netherlands, have the highest adoption of the circular economy. This information can be valuable for identifying leaders in circular practice implementation and potentially developing countries in this direction. The research can also serve as a basis for further enhancing the methodology of monitoring indicators of sustainable development, circular economy, and innovation in European Union countries.
Environmental compliance and business strategies practices of entrepreneurial ventures
Authors: Stupnytskyi Viktor , Filipishyna Liliya , Chumak Oksana , Gonchar Viktoriya , Komandrovska Veronika , Iefimova Ganna
Published: August 2023

The study is devoted to the research of environmental compliance and business strategies of the practice of venture enterprises. The purpose of the study is to determine the role of environmental compliance in the business strategies of enterprises and to reveal the potential of a positive impact on sustainable development. The paper examines hypotheses regarding the favourable impact of environmental compliance on the competitiveness and innovative potential of enterprises. Environmental compliance and business strategies of enterprises have the potential to promote sustainable environmental development, which is currently only 10% used. This requires the active participation of enterprises in the implementation of environmental practices, investments in innovative solutions and the development of knowledge. The study highlights the need to support and promote practices such as venture entrepreneurship, which contribute to the creation of new environmentally relevant technologies, products and services. Therefore, the results of this work indicate the importance of developing and implementing ecologically appropriate business strategies in business practices. This can contribute to improving the environmental condition, ensuring sustainable development and strengthening the competitive positions of national economies.
Die psychiatrische Klinik der Universität Würzburg um 1900
Authors: Krings Moritz
Published: August 2023

Im ausgehenden 19. Jahrhundert kam es in Deutschland zu einer Reihe von Neugründungen universitärer psychiatrischer Kliniken, welche den wissenschaftlichen Charakter der Fachrichtung betonten und das Selbstbewusstsein und Selbstverständnis der psychiatrischen Fachdisziplin mitprägten. Dennoch sind viele der entsprechenden Kliniken in der psychiatriehistorischen Forschung bis heute unzureichend untersucht worden. Die vorliegende Arbeit möchte hier einen Beitrag leisten, indem exemplarisch die psychiatrische Klinik der Universität Würzburg um 1900 betrachtet wird, welche die erste Gründung einer eigenständigen psychiatrischen Klinik in Bayern und eine der frühen Gründungen in Deutschland insgesamt darstellte. Der Fokus liegt dabei auf der Analyse des 1893 eröffneten Neubaus sowie der damit einhergehenden Funktionen und Konzepte. Des Weiteren wird ein Überblick über das an der Klinik tätige Personal gegeben.
Von den klinischen Charakteristika zur sicheren Diagnose funktioneller neurologischer Bewegungsstörungen
Authors: Weißbach Anne , Hamami Feline , Münchau Alexander , Ganos Christos
Published: August 2023

Funktionelle neurologische Bewegungsstörungen gehören zu den häufigsten neurologischen Erkrankungen, führen oft zu einer erheblichen Einschränkung der Lebensqualität der Betroffenen und zu einer massiven finanziellen Belastung des Gesundheitssystems. Die Diagnose wird klinisch anhand positiver Diagnosekriterien gestellt, was apparative, kostenintensive Zusatzdiagnostik meist unnötig macht. Gehäuft kommt es allerdings zu einer erheblichen Verzögerung der Diagnose und damit verbunden, der Einleitung einer krankheitsspezifischen Therapie. In unserem Artikel möchten wir die Hauptpfeiler der klinischen Diagnose – die Inkongruenz und Inkonsistenz – die allen funktionellen Bewegungsstörungen gemeinsam ist, erläutern und darauf aufbauend die unterschiedlichen Subgruppen mit ihren individuellen klinischen Charakteristika und den dazugehörigen Untersuchungstechniken praxisnah erklären. Dies soll dazu beitragen, dass die Diagnose schnell und sicher gestellt werden kann. Außerdem ergeben sich aus den aufgeführten klinischen Charakteristika für die Therapie bedeutsame Strategien, z. B. die Modulation von Aufmerksamkeit, die in der Physio- und Psychotherapie zur Anwendung gebracht, aber vor allem durch die Patienten selbst genutzt werden können.
Behandlungsansätze für das Post-Covid-Syndrom
Authors: Langhorst Jost
Published: August 2023

Etwa 10 % der Menschen, die sich mit SARS-CoV-2 infiziert haben, leiden nach der Akutinfektion unter dem sogenannten Post-Covid-Syndrom. Symptome hierbei sind Fatigue, Myalgie, Intoleranz für körperliche Betätigung, Schlafstörungen, Konzentrationsschwierigkeiten oder Angstzustände. Die Leitlinie zur Behandlung von Post Covid oder Long Covid empfiehlt eine multimodale und interdisziplinäre Therapie. In der Klinik für Integrative Medizin und Naturheilkunde am Klinikum Bamberg werden Post-Covid-Patient*innen mit Verfahren der Mind-Body-Medizin, der Mindfulness-Based Stress Reduction (MBSR), mit Yoga, Akupunktur, Phytotherapie, naturheilkundlichen Selbsthilfestrategien und wassergefilterter Infrarot-A-Ganzkörperhyperthermie behandelt.
Palladium/Charcoal-Catalysed Olefin Reduction for the Simple and Efficient Synthesis of Substituted gem-Diborylalkanes
Authors: Panda Santanu , Das Kanak Kanti , Ghorai Debraj , Mahato Somenath
Published: August 2023

gem-Diborylalkanes have recently emerged as valuable synthons for diverse C–C bond-forming reactions. They represent an important class of bifunctional reagents that can be applied for the synthesis of simple to complex skeletons. Herein, we report a Pd-catalysed hydrogenation method for the synthesis of gem-diborylalkanes from the corresponding gem-diborylalkenes, which are themselves prepared from the corresponding aldehydes and ketones using known procedures. In addition, transformations of two representative gem-diborylalkane products are discussed leading to a range of functionalised derivatives.
Electrochemical Decarboxylative Minisci-Type Acylation of Quinoxalines under Catalyst- and External-Oxidant-Free Conditions
Authors: Liang Sen , Xu Kun , Zeng Chengchu , Li Yongmei , Wang Dehui
Published: August 2023

An electrochemical approach for the Minisci-type acylation of quinoxalines with α-keto acids as the acyl radical precursors is reported. With the assistance of TFA as the key additive, acylated quinoxalines were constructed in synthetically useful yields. The distinguishable features of this electrochemical protocol include catalyst- and external oxidant-free conditions, and operational simplicity.
The Importance of Parental Leave and Lactation Support for Surgeons
Authors: Kanters Arielle E. , Shubeck Sarah P.
Published: August 2023

Despite the growing population of surgeons who will spend the bulk of their potential childbearing years in medical school, training, or early in practice, the stigma associated with pregnancy remains. The challenges of childbearing for surgeons also extend to the pregnancy experience from a health perspective including increased rates of infertility, miscarriage, and preterm labor. Given the unique demands of a surgical practice, surgeons may experience pressure to minimize the disruption of their work during and after pregnancy. This may include attempts at carrying a full workload until the day of delivery, reducing the length of planned parental leave, and not requesting accommodations for time to express milk. Concern for discrimination, clinical productivity expectations, and promotion timelines can limit a surgeon's ability to receive pregnancy-related support and adequate parental leave. Though not all surgeons will choose to pursue pregnancy, we must still acknowledge the need to support these individuals. Furthermore, this support should not be limited to the pregnancy alone but include postpartum support including that related to family leave and lactation. Here, we provide an overview of just some of the challenges faced by surgeons in the pursuit of parenthood and present the arguments for accommodations related to pregnancy, parental leave, and lactation.
Systematic correspondence in co-evolving languages
Authors: Wu Junru , Zhao Junyuan
Published: August 2023

Language co-evolution is an influential cultural force, impacting the past, present, and future of human languages. Systematic correspondence identifies corresponding features in languages evolving together, such as English "d" and German "t" in word pairs like “deed–Tat” and “deep–tief”. This study examines how social ecology influences lexical-phonological systematic correspondence using a vector-based measurement—weighted cosine systematicity—across two co-evolutionary lexical datasets for comparison: old to recent English-German related words, and thirty-year sliced morphemic transcriptions for Chinese dialects in Shanghai. Results show that even when related but socially independent languages evolve in different directions, they can maintain an equilibrium in systematic correspondence over centuries. In contrast, dialects can rapidly converge towards their national high variety in terms of lexical-phonological similarities, and the regional standard in terms of systematic correspondence within decades. This suggests that self-regulation of cross-linguistic systematic correspondence has its own, yet complementary, mechanism compared to the similarity-based co-evolutionary mechanism, making it a meaningful indicator and predictor for cross-linguistic lexical co-evolution.
Low-temperature anomalies in solid 4He (Review article)
Authors: Chishko K. A.
Published: August 2023

The thermodynamic and mechanic anomalies within the region 0.1–0.5 K experimentally observed in hexagonal close-packed solid 4He crystal are discussed and interpreted on the basis of a polytypic HCP structure (close-packed stack of 2D crystalline planes on the triangular lattice). It elucidated the principal role of the stacking faults and Shockley’s partial dislocations in the quite unexpected low-temperature behavior of the solid 4He.
Influence of mechanical stress on electron transport properties of second-generation high-temperature superconducting tapes
Authors: Gaifullin M. , Lee S. , Kelleher J. F. , Kabra S. , Myronov M. , Evans B. E. , Kirichek O.
Published: August 2023

Second-generation high-temperature superconductor (2G HTS) tapes have demonstrated the ability to generate high magnetic fields and critical currents at a wide operating temperature range. In this paper, we study the mechanical properties of 2G HTS tape measured simultaneously with its critical current. The lattice deformations in the tape’s substrate caused by applied mechanical stress were measured by neutron diffraction. In our experiments, the 2G HTS tape was exposed to uniaxial tensile force ranging from 250 to 1100 N at temperature 77 K. The current through the tape was scanned in the range from 22 to 42 A. The experimental results have been obtained in a cryogenic testing chamber for neutron scattering measurements of internal stresses under load with the incorporated HTS current leads. Critical stress is a vital parameter required for the modeling and designing of advanced superconducting magnets and also a variety of different superconducting applications based on 2G HTS tapes.
Magnetoresistance peculiarities of Bi95.69Mn3.69Fe0.62 in magnetic fields up to 140 kOe
Authors: Terekhov A. V. , Rogacki K. , Yarovyi V. M. , Stepanov V. B. , Kolesnichenko Yu. A. , Shevchenko A. D. , Kovalyuk Z. D. , Lähderanta E. , Solovjov A. L.
Published: August 2023

The magnetic-field dependences of the electrical resistivity Δρ/ρ0(Η) of the textured polycrystal Bi95.69Mn3.69Fe0.62 have been studied for the first time, for the H⊥I and H || I configurations at temperatures 5, 80, 150, and 300 K. It has been established that the Δρ/ρ0(Η) dependences significantly differ from those obtained for pure bismuth due to the influence of the internal magnetism of the α-BiMn phase inclusions on the behavior of charge carriers in the bismuth matrix. The maxima of Δρ/ρ0(Η) at H ≈ 30 and ≈ 40 kOe have been found, for the longitudinal and transverse magnetoresistance, respectively. These maxima may be related to reaching the quantum limit in the material we have studied.
Characterizing fluid dynamical systems using Euler characteristic surface and Euler metric
Authors: Roy A. , Haque R. A. I. , Mitra A. J. , Tarafdar S. , Dutta T.
Published: August 2023

Euler characteristic (χ), a topological invariant, helps to understand the topology of a network or complex. We demonstrate that the multi-scale topological information of dynamically evolving fluid flow systems can be crystallized into their Euler characteristic surfaces χs(r,t). Furthermore, we demonstrate the Euler Metric (EM), introduced by the authors, can be utilized to identify the stability regime of a given flow pattern, besides distinguishing between different flow systems. The potential of the Euler characteristic surface and the Euler metric have been demonstrated first on analyzing a simulated deterministic dynamical system before being applied to analyze experimental flow patterns that develop in micrometer sized drying droplets.
Nature of unsteady and acoustic behavior in an elliptic sonic jet with aft-deck
Authors: Rao A. Nageswara , Kushari Abhijit
Published: August 2023

An experimental investigation is carried out on the under expanded sonic jet issuing from an elliptic nozzle with aft-deck at two different Mach numbers (Mj). Flow characteristics including shock-cell structure, jet separation, and pressure variation over the aft-deck wall are investigated with the help of schlieren images, oil flow visualization, and steady pressure measurements. A complex shock-structure is found to exist in the x-z and x-y planes due to the shape and curvature of the aft-deck for Mj = 1.35 and 1.56. The shock-induced jet separation is identified at x/L ∼ 0.75 for Mj = 1.56, whereas no separation is identified for Mj = 1.35. Synchronized acoustic and unsteady measurements reveal the coupling between the shock-induced jet separation on the aft-deck wall and the far-field noise emissions. Acoustic spectra elucidate the strong tonal noise component corresponding to the flapping Mode-B at St ∼ 0.68 for Mj = 1.56. Moreover, the noise components including screech tones, broad-band shock-associated noise, and turbulent mixing noise are dominant for the azimuthal angle ϕ = 0°. The dominant flow mode from proper orthogonal decomposition analysis shows the existence of strong jet flapping and upstream-traveling acoustic waves for the separated jet.
Ensemble data assimilation-based mixed subgrid-scale model for large-eddy simulations
Authors: Wang Yunpeng , Yuan Zelong , Wang Jianchun
Published: August 2023

An ensemble Kalman filter (EnKF)-based mixed model (EnKF-MM) is proposed for the subgrid-scale (SGS) closure in the large-eddy simulation (LES) of turbulence. The model coefficients are determined through the EnKF-based data assimilation technique. The direct numerical simulation (DNS) results are filtered to obtain the benchmark data for the LES. Reconstructing the correct kinetic energy spectrum of the filtered DNS (fDNS) data has been adopted as the target for the EnKF to optimize the coefficient of the functional part in the mixed model. The proposed EnKF-MM framework is subsequently tested in the LES of both the incompressible homogeneous isotropic turbulence and turbulent mixing layer. The performance of the LES is comprehensively examined through the predictions of the flow statistics including the velocity spectrum, the probability density functions (PDFs) of the SGS stress, the PDF of the strain rate, and the PDF of the SGS energy flux. The structure functions, the evolution of turbulent kinetic energy, the mean flow, the Reynolds stress profile, and the iso-surface of the Q-criterion are also examined to evaluate the spatial–temporal predictions by different SGS models. The results of the EnKF-MM framework are consistently more satisfying compared to the traditional SGS models, including the dynamic Smagorinsky model, the dynamic mixed model, and the velocity gradient model, demonstrating its great potential in the optimization of SGS models for the LES of turbulence.
A Swin-transformer-based model for efficient compression of turbulent flow data
Authors: Zhang Meng , Yousif Mustafa Z. , Yu Linqi , Lim Hee-Chang
Published: August 2023

This study proposes a novel deep-learning-based method for generating reduced representations of turbulent flows that ensures efficient storage and transfer while maintaining high accuracy during decompression. A Swin-transformer (ST) network combined with a physical constraints-based loss function is utilized to compress the turbulent flows with high compression ratios and then restore the data with underlying physical properties. The forced isotropic turbulence is used to demonstrate the ability of the ST-based model, where the instantaneous and statistical results show the excellent ability of the model to recover the flow data with a remarkable accuracy. Furthermore, the capability of the ST model is compared with a typical convolutional neural network-based auto-encoder (CNN-AE) by using the turbulent channel flow at two friction Reynolds numbers Reτ = 180 and 550. The results generated by the ST model are significantly more consistent with the direct numerical simulation data than those recovered by the CNN-AE, indicating the superior ability of the ST model to compress and restore the turbulent flow. This study also compares the compression performance of the ST model at different compression ratios (CR s) and finds that the model has low enough error even at very high CR. Additionally, the effect of transfer learning (TL) is investigated, showing that TL reduces the training time by 64% while maintaining high accuracy. The results illustrate for the first time that the Swin-transformer-based model incorporating a physically constrained loss function can compress and restore turbulent flows with the correct physics.
Polynitrogen clusters interaction with water: experimental and theoretical perspectives
Authors: Ding Kewei , Wang Peng , Zhou Wenli , Xu Hongguang , Ge Zhongxue , Zheng Weijun , Lu Cheng
Published: August 2023

Polynitrogen clusters are of great interest as potential high-energy-density materials (HEDMs). However, it is still a challenge to effectively manufacture pure nitrogen clusters. Here, we present a method to produce all-nitrogen clusters ranging in size from 3 to 10 using a self-developed apparatus consisting of a laser vaporization cluster source and a mass spectrometer. The results indicate that the mass peak of the N4
+ cluster is dominant, and the cooling of the cluster source with liquid nitrogen effectively enhanced the intensities of larger nitrogen clusters. The trace amounts of water in the carrier gas affects the relative signal intensities of nitrogen clusters, suggesting that water molecules can affect their stabilities. The geometrical structures of the N

n

+

/

0

(n = 3–10) clusters are determined by CALYPSO cluster structural search method and density functional theory calculations. A series of promising polynitrogen clusters, such as Z-shaped N

4

+

/

0

clusters and bicyclic N

8

+

/

0

clusters, are identified. The molecular dynamics simulations indicate the decomposition energy barrier of (N4–H2O)+ cluster is lower than that of N4
+ cluster by 2.3 kcal mol−1, while the decomposition energy barrier of (N8–H2O)+ cluster is higher than that of N8
+ cluster by 1.4 kcal mol−1. These findings provide useful information for the generation and stabilization of polynitrogen clusters, which are valuable for the design and synthesis of HEDMs.
Electronic, transport and optical properties of ZnO/GaN heterostructures: first-principles study
Authors: Wakhare Sandhya Y , Deshpande Mrinalini D
Published: August 2023

The electronic, transport and optical properties of the trilayer of ZnO and GaN heterostructures are investigated using density functional study to understand its role in optoelectronic devices. For layered systems, Zn over N and Ga over O stacking arrangement of ZnO over GaN is most favorable. The calculated formation energies reflect the energetically favorable condition of ZnO/GaN heterostructures. The GaN/ZnO/GaN is a more energetically favorable stacking arrangement as compared to ZnO/GaN/ZnO. The band gap of trilayer systems decreases as compared to that of bilayer and monolayer. The ZnO/GaN bilayer and ZnO/GaN/ZnO trilayer show direct band gap characteristics with the value of 1.71 and 1.61 eV, respectively. The GaN/ZnO/GaN shows an indirect band gap of 1.47 eV. The higher recombination rate of ZnO/GaN/ZnO is useful to develop a base for optical emission devices. The transport calculations show that, the magnitude of current flowing through the system increases with the layers of heterosystems and specifically higher for GaN/ZnO/GaN heterostructure. The enhanced channel conductance and higher mobility of GaN/ZnO/GaN heterostructure are crucial for the development of high mobility transistors. The improved absorption energy and dielectric properties are observed for trilayer systems as compared to that of the bilayer and monolayer and may be useful for optical devices. The higher optical efficiency is observed for GaN/ZnO/GaN as compared to ZnO/GaN/ZnO heterostructure system and opens up a way toward optical waveguides and reflectors.
Influence of pulse width on the breakdown process of nanosecond pulse discharge at low pressure
Authors: Wang Qixuan , Wu Hao , Wang Yu , Zhang Ye , Jiang Wei , Zhang Ya
Published: August 2023

Pulsed plasma discharge breakdown has long been a subject of research in the field of plasma physics. However, the spatial distribution and temporal evolution of parameters such as the density, energy, and electric field of charged particles during the breakdown process have not been thoroughly investigated. In this study, we investigate the breakdown process under nanosecond pulses with different pulse widths (1 ns, 10 ns, and 100 ns), utilizing the 1D implicit particle-in-cell/Monte Carlo collision method. Our simulation results indicate that pulse width plays a crucial role in the evolution of plasma breakdown. Specifically, under ultra-short pulses, the breakdown occurs after the pulse voltage ceases, demonstrating that increasing pulse width accelerates the changes in plasma parameters but does not affect the breakdown time. Under longer pulses, the removal of voltage leads to a significant increase in the thickness of the anode sheath. As the pulse width continues to increase, the ions collide in the cathode sheath after the pulse ends, resulting in ion energy loss. Finally, by scanning the parameter space, we give the Paschen curve and observe a higher breakdown voltage in the pulse case and the impact of ion secondary electrons.
Shallow junction formation via lateral boron autodoping during rapid thermal process
Authors: Yu Yingtao , Gauthier Nicolas , Primetzhofer Daniel , Zhang Zhen
Published: August 2023

Autodoping is a well-known phenomenon of unwanted dopant transfer in silicon epitaxy process. In this work, we discovered boron lateral autodoping in normal rapid thermal process (RTP) and used it to controllably form shallow junctions for device fabrication. The redeposition of boron from the gas phase to the solid surface was identified to be the limiting step of the boron incorporation into the undoped silicon area in the RTP process. At a given RTP temperature, boron autodoping could be increased by elevating the concentration of the boron source or enhancing the evaporation coefficient. Extending the annealing time can substantially improve the uniformity of the boron concentration in the gas phase, thus reducing the pattern dependence of the autodoping results. In addition, the autodoping process also avoids the traps and defects induced by ion implantation. Therefore, the described mechanism holds great promise for shallow junction formation in selectively patterned area with low cost.
Monolayer TiSi 2
P
4
as a high-performance anode for Na-ion batteries
Authors: Peng Jie , Wang Zhi-Yong
Published: August 2023

Exploring anode materials with overall excellent performance remains a great challenge for rechargeable Na-ion battery technologies. Herein, we have identified that monolayer TiSi

2

P

4

is just such a prospective anode candidate via first-principles calculations. It is showed to be dynamically, thermally, mechanically, and energetically stable, which provides feasibility for experimental realization. The Na diffusion on the its surface is proved to be ultrafast, with a migration energy barrier as low as 73 meV. Electronic structure confirms that the pristine system undergoes a transition from the semiconductor to metal during the whole sodiation process, which is a significant advantage to the electrode conductivity. More excitingly, monolayer TiSi

2

P

4

can accommodate up to double-sided five-layer adatoms, resulting in an ultrahigh theoretical capacity of 1176 mA h g−1 and a low average open-circuit voltage of 0.195 V. Moreover, the maximally sodiated electrode monolayer yields rather small in-plane lattice expansion of only 1.40%, which ensures reversible deformation and excellent cycling stability as further corroborated by structural relaxation and ab initio molecular dynamics simulation. Overall, all of these results point to the potential that monolayer TiSi

2

P

4

can serve as a promising anode candidate for application in high-performance low-cost Na-ion batteries.
Effect of Al2Cu constituent layer thickness discrepancy on the tensile mechanical behavior of Cu/Al2Cu/Al layered composites: a molecular dynamics simulation
Authors: Bian Xiaoqian , Wang Aiqin , Xie Jingpei , Liu Pei , Mao Zhiping , Liu Zhenwei
Published: August 2023

Nano-polycrystalline Cu/Al2Cu/Al layered composites with different layer thicknesses d of single-crystal Al2Cu constituent are constructed. The effects of d on the strength and fracture modes of nano-polycrystalline Cu/Al2Cu/Al layered composites are systematically investigated by molecular dynamics simulations. The uniaxial tensile results show that the ultimate strength and fracture mode of the nano-polycrystalline Cu/Al2Cu/Al layered composites do not change monotonically with the change of single crystal Al2Cu constituent layer thickness d, the ultimate strength peaking at d = 2.44 nm, and the toughness reaching the optimum at d = 4.88 nm. The improvement of deformation incompatibility between Cu, Al and Al2Cu components increases the ultimate strength of polycrystalline Cu/Al2Cu/Al laminated composites. Due to the high activity of Cu dislocation and the uniformity of strain distribution of single crystal Al2Cu, the fracture of nano-crystalline Cu/Al2Cu/Al layered composites changes from brittleness to toughness. This study is crucial to establish the organic connection between microstructure and macroscopic properties of Cu/Al layered composites. To provide theoretical basis and technical support for the application of Cu/Al layered composites in high-end fields, such as automotive and marine, aerospace and defense industries.
Analytical modeling of a magnetoactive elastomer unimorph
Authors: Pan Tan , Leng Rui , Uitz Oliver , Seepersad Carolyn , Ounaies Zoubeida , Frecker Mary
Published: August 2023

Magnetoactive elastomers (MAEs) are capable of large deformation, shape programming, and moderately large actuation forces when driven by an external magnetic field. These capabilities enable applications such as soft grippers, biomedical devices, and actuators. To facilitate complex shape deformation and enhanced range of motion, a unimorph can be designed with varying geometries, behave spatially varying multi-material properties, and be actuated with a non-uniform external magnetic field. To predict actuation performance under these complex conditions, an analytical model of a segmented MAE unimorph is developed based on beam theory with large deformation. The effect of the spatially-varying magnetic field is approximated using a segment-wise effective torque. The model accommodates spatially varying concentrations of magnetic particles and differentiates between the actuation mechanisms of hard and soft magnetic particles by accommodating different assumptions concerning the magnitude and direction of induced magnetization under a magnetic field. To validate the accuracy of the model predictions, four case studies are considered with various magnetic particles and matrix materials. Actuation performance is measured experimentally to validate the model for the case studies. The results show good agreement between experimental measurements and model predictions. A further parametric study is conducted to investigate the effects of the magnetic properties of particles and external magnetic fields on the free deflection. In addition, complex shape programming of the unimorph actuator is demonstrated by locally altering the geometric and material properties.
Strong chiral optical force for small chiral molecules based on electric-dipole interactions, inspired by the asymmetrical hydrozoan Velella velella
Authors: Cameron Robert P , McArthur Duncan , Yao Alison M
Published: August 2023

Drawing inspiration from a remarkable chiral force found in nature, we show that a static electric field combined with an optical lin

⊥

lin polarization standing wave can exert a chiral optical force on a small chiral molecule that is several orders of magnitude stronger than other chiral optical forces proposed to date, being based on leading electric-dipole interactions rather than relying on weak magnetic-dipole and electric-quadrupole interactions. Our chiral optical force applies to most small chiral molecules, including isotopically chiral molecules, and does not require a specific energy-level structure. Potential applications range from chiral molecular matter-wave interferometry for precision metrology and tests of fundamental physics to the resolution of enantiomers for use in chemistry and biology.
Hyper-entangling mesoscopic bound states
Authors: Sreedharan Aparna , Kuriyattil Sridevi , Wüster Sebastian
Published: August 2023

We predict hyper-entanglement generation by binary scattering of mesoscopic bound states, considering solitary waves in Bose–Einstein condensates containing thousands of identical Bosons. For it to occur, the underlying many-body Hamiltonian must not be integrable, and the pre-collision quantum state of the solitons needs to be fragmented. Under these conditions, we show that the post-collision state will be hyper-entangled in spatial degrees of freedom and atom number within solitons, for realistic parameters. The effect links aspects of non-linear systems and quantum-coherence and the entangled post-collision state challenges present entanglement criteria for identical particles. Our results are based on simulations of colliding quantum solitons in a quintic interaction model beyond the mean-field, using the truncated Wigner approximation.
The effect of night sky background on source reconstruction in atmospheric Cherenkov telescope arrays and implications for image cleaning
Authors: Sajjad Saeeda
Published: August 2023

Gamma-ray astronomy through imaging atmospheric Cherenkov telescope (IACTs) has enabled the study of numerous astrophysical sources in the GeV-TeV domain. The presence of night sky background (NSB) in IACT images affects the reconstruction of the gamma-ray being observed and is usually dealt through image cleaning. In this work, we propose that the image cleaning approach might be adapted to the reconstruction method and NSB levels. In particular, we study the effect of NSB on source reconstruction for gamma-rays observed through IACT arrays through Monte Carlo simulations. We find that the presence of NSB can have a smoothing effect on the shower images enabling better source reconstruction under certain circumstances. We also find that there is an optimum cleaning threshold depending on the energy of the initial gamma-ray. This threshold shows very little dependence on the NSB level or core position. Based on these results, we propose and test a hybrid image cleaning method for source reconstruction. We find that this hybrid image cleaning method results in better source reconstruction when observations are made in high NSB conditions. Whereas at low NSB levels, the application of a single image cleaning threshold yields better results. We finally conclude that this implies that different image cleaning methods might be needed to best carry out source reconstructions at different NSB levels.
Painlevé analysis, multi-kinks and hybrid nonlinear waves for an extended (3 + 1)-dimensional B-type Kadomtsev-Petviashvili equation
Authors: Ahtisham Ilyas Muhammad , Javid Ahmad , Wazwaz Abdul-Majid
Published: August 2023

In this paper, we study an extended (3+1)-dimensional B-type Kadomtsev-Petviashvili equation having applications in diverse scientific fields. Painlevé anlysis is carried out to test the integrability of the model under consideration. Hirota’s simplified technique is used to investigate one, two and three kink-soliton solutions. Using a dependent variable transformation, bilinear form of the model is obtained which is then used to report lump and lump interaction solutions with periodic and kink waves. The dynamical properties and nature of obtained solutions is comprehensively studied using 3d and 2d graphs.
Theoretical study of magnetoacoustic mode in stellar atmospheres
Authors: Sadiq Safeer
Published: August 2023

Radiation magnetohydrodynamic (RMHD) theory is presented in the nonequilibrium diffusion grey radiation limit. Basic set of equations is perturbed to find the dispersion relation of small amplitude (linear) waves in RMHD plasma. It is found that magnetoacoustic waves have dispersion and damping in the RMHD plasma. It is also concluded that for very long wavelength magnetosonic mode, to create wave motion in the medium the restoring force is provide the radiation pressure and inertia is provided by matter. The effects of radiation energy, diffusivity and plasma beta on the dispersion and damping of magnetoacoustic mode in RMHD plasma are shown in the form of graphs. The model is applicable to the stellar atmosphere.
Adjustable symmetry on the dynamics of a new chaotic system with cyclic symmetry: theoretical study, control and experimental investigation
Authors: Boui A Boya Bertrand Frederick , kengne Jacques
Published: August 2023

In this study, we propose a new chaotic autonomous system with adjustable cyclic and central symmetries. The new 3D system, with rich dynamics, is constructed based on the Thomas model. A detailed study of the nonlinear dynamics arising from the model allows us to reveal complex behaviors of different phenomena such as hysteresis dynamics, offset boosting, total amplitude control, and coexistence of several homogeneous and heterogeneous attractors in both regimes (symmetric and asymmetric). The control of multistability of the new cyclic system is studied by following the technique of linear augmentation. An analog electronic version of the model is designed and then simulated using the Pspice software. Moreover, a physical implementation using the arduino microcontroller makes it possible to validate the results of the theoretical analysis.
Probing the Atmospheric Precipitable Water Vapor with SOFIA, Part. IV. Water Vapor Estimates from FORCAST Grism Spectra
Authors: Vacca W. D. , Iserlohe C. , Shenoy S. , Clarke M. , Fischer C. , Thorpe A. , Chambers E.
Published: August 2023

SOFIA was an airborne observatory for far-infrared astronomy stationed at the Armstrong Flight Research Center in Palmdale, CA, USA. Although SOFIA flew at altitudes of ∼41,000 ft, any far-infrared observations from within the Earth’s atmosphere are nevertheless hampered by water vapor absorbing the astronomical signal. The primary atmospheric parameter governing absorption at far-infrared wavelengths is the total upward precipitable water vapor (PWV). In this paper we present a method of deriving PWV values directly from low resolution (R ∼ 100–200) mid-infrared (5–40 μm) spectroscopic observations and apply it to low resolution grism spectra obtained with the FORCAST instrument on-board SOFIA. We then compare these values with those determined from the fifth European Re-analysis (ERA5) of the global atmospheric parameters provided by the European Centre for Medium-Range Weather Forecasts (ECMWF) for the time and altitude corresponding to the SOFIA observations. In general, we find a very good correlation between the ERA5-ECMWF values and the values derived from the FORCAST grism spectra, especially for high signal-to-noise ratio data. These results indicate that ERA5-ECMWF PWV values can be used to generate the telluric corrections for FORCAST imaging data as well as grism spectra for which the PWV values cannot be determined directly. We also derive the resolving power of the various grism and slit width combinations for FORCAST. Our results will be useful for reprocessing the FORCAST data in the SOFIA archive.