bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental investigation on the vibrational and fluid dynamics behaviour of a turbocharger compressor in the transition to surge operation
Authors: Silvestri Paolo , Marelli Silvia , Usai Vittorio
Published: August 2023

High-speed dynamic centrifugal compressors are widely used both in the modern internal combustion engine design and in advanced pressurized cycles and innovative plant layouts as fuel cell systems. Surge strongly limits the stable operating region of centrifugal compressors in low mass flow rate conditions especially during fast transients. Therefore, it is of great importance to investigate transient system dynamic response of compressor surge evolution and early detection of incipient compressor surge. A specific experimental investigation on compressor surge was carried out at the University of Genoa turbocharger test facility and results are presented and analysed in this paper. The activity consists of steady state and transient measurements used to characterize and identify compressor behaviour in correspondence of surge inception conditions. The frequency and time frequency data analysis have been applied on inflow pressure, anemometric and vibrational signals to identify their contents and so to be able to classify compressor operation as stable or unstable. Synchronous averages performed in the time domain have been identified as a suitable algorithmic tool to detect incipient surge conditions. Anemometric signal analysis allowed to identify intermitting phenomena in deep surge conditions may be related to the rise of a rotation stall condition. The obtained results provide original diagnostic and predictive methods to be integrated in a monitoring system capable of preventing surge and extending compressor operating range, performance and reliability to allow the integration with the other plant components.
An Updated Design Procedure for Tesla Turbines
Authors: Renuke Avinash , Traverso Alberto , Kalfas Anestis
Published: August 2023

Tesla turbine rotor, a special case of the flow between two corotating disks, has been studied in the past analytically and the performance is discussed both qualitatively and quantitatively. However, there is no systematic design criteria/process given to design the rotor of a Tesla expander in the peer-reviewed literature. Such design procedure, presented in this article, allows researchers and engineers to design and optimise the rotor for a given fluid and design condition (Power, flow and rotational speed). In this article, we present a 0-D design methodology to calculate rotor design parameters such as disk diameters, the gap between disks, the number of disks and the rotational speed of the expander, and efficiency and power estimation. This design procedure is based on the correlations and optimal ranges present in the literature. The 0-D model discussed in this article is a promising design approach to the preliminary design of the Tesla rotor and then further fine-tuning could be done based on the CFD simulations when coupled with the stator. A case study is presented with a 3-kW air bladeless expander prototype in which the rotor is designed using the 0-D model approach and compared with 2D Computational Fluid Dynamics results.
Energy management and load profile optimisation of 10 kWh BESS integrated into a Smart Polygeneration Grid subnetwork
Authors: Raggio Martina , Niccolini Marmont Du Haut Champ Carlo Alberto , Reboli Tommaso , Silvestri Paolo , Ferrari Mario Luigi
Published: August 2023

Smart Polygeneration Grids integrate different prime movers, such as traditional generators, renewable energy sources and energy storage systems to locally supply electrical and thermal power to achieve high conversion efficiencies and increase self-consumption. Integrating different energy systems poses some challenges on the plant Energy Management Systems (EMS), which must accommodate different operational requirements while following the electrical and thermal loads. Battery Energy Storage Systems (BESSs) can provide additional flexibility to the system. This paper intends to evaluate the impact of integrating a Ni-Zn-based BESS into an existing cogeneration plant through a dedicated sensitivity analysis over the operative characteristics of the BESS itself (maximum power and capacity). The IES LAB of the Savona’s Campus already contains different energy systems: a cogenerative micro gas turbine, a heat-pump, solar thermal panels and two thermal energy storage systems that provide electricity and thermal power to the Smart Polygeneration Grid of the Campus. A new developed energy scheduler accommodates the integration of the new battery and meets the electrical and thermal demands. The aim is to demonstrate that integrating the BESS provides additional benefits in the system management and can reduce fuel usage and OPEX.
Battery energy storage systems for ancillary services in Renewable energy communities
Authors: Ferrucci Tommaso , Fioriti Davide , Poli Davide , Barberis Stefano , Vannoni Alberto , Roncallo Francesco , Tacconelli Carlo , Gambino Valeria
Published: August 2023

This document presents a study on the use of battery energy storage systems in a proposed renewable energy community in Savona, UNIGE Campus. The study compares the outcomes of cooperative approaches with and without flexibility services to a scenario where users do not cooperate. The study concludes that storage systems of relevant size can create new flexible instruments for the power grid and a powerful tool for citizens, which could make the investment into BESS financially viable. The study also suggests that greater transparency and information on hourly energy sales and purchase prices would facilitate awareness among community members and at the same time stimulate discussion of alternative technologies such as batteries to cover the most expensive nighttime periods for users. Overall, the study highlights the potential of battery systems in renewable energy communities in Italy and provides insights into the importance of coupling flexible services with capacity-building activities and awareness campaigns to promote demand-side-response activities and storage technologies.
Performance of the main technologies demonstrated in the ENVISION project
Authors: Finocchi Paolo , Rattazzi Diego , Tavaroli Fabrizio , Spigliantini Giorgia
Published: August 2023

Within the context of ENVISION project, different technologies have been developed aiming to harvest energy being integrated into the building façade. These technologies have been tested in different demosites with a monitoring phase of around one year in order to assess their performances on-field. The technologies developed within ENVISION and reported in this article are solar façade collectors coupled with Heat Pumps and PV windows. The present paper reports the assessment of the performance of the ENVISION technologies in the different demos. This analysis is carried out through the calculation of normalized KPIs related to four different domains (energy, social, economic, and environmental) and the aggregation of these KPIs in domain scores to understand the strengths and weaknesses of each demo. In all the different demosites, the monitored data have been collected and processed to calculate the most valuable KPIs, which are compared with state-of-the-art values found in the literature to calculate a normalized KPI. Depending on the obtained value of the normalized KPIs a score from 0 (worst performance) to 5 (best performance) is assigned, considering that a score of 3/5 has been assigned to the State-Of-the-Art. Some KPIs are specific for the single demo (e.g. the SCOP of the heat pump), while others are common to all the demos and were used to carry on a direct comparison between the technologies. All the demos showed promising results in the social, energy, and environmental domains. For the last domain, in particular, the best results are obtained, as each technology leads to significant savings in GHG emissions. There is room for improvement on the economic side, which can be filled by progressively lowering the cost of technology over the years.
Digital technologies in oil and gas production as a tool to ensure optimal energy efficiency and sustainability
Authors: Ivanova Tatyana
Published: August 2023

Implementation of smart production technologies, digital technologies, and Industry 4.0 technologies in the oil production industry as a type of innovative management are indispensable tools for strengthening strategic, financial, and innovative sustainable development of enterprises operating in highly competitive domestic and foreign markets. Such technologies make it possible to adjust enterprise strategies promptly in real-time. All field digitalization solutions, operation of production units with any voltage and frequency level, heating, etc. are not workable without electric power. Electric motors of drilling rigs, downhole surfaces, and underground equipment use about 70 - 72% of all electricity consumed during oil and gas production. The authors give examples of energy-saving measures and the results of their implementation. Efficiency, energy conservation, and sustainable development are the challenges oil producers face today. The article considers strategic management in reality as a new trend in the sustainable development of oil production enterprises. Varying strategy in real time gives the oil-producing enterprises a general focus, individuality, daily simple actions, readiness to consider new ideas, and not being afraid to decide and take responsibility for them. The authors also analyzed the sustainable development strategies of the leading oil-producing companies in Russia. The article offers performance indicators for the sustainable development of oil and gas-producing companies.
The efficiency of using ductile iron water pipes in soft soil
Authors: Primin O.
Published: August 2023

At the present stage of reforming the housing and public services, toughening the requirements for the life and reliability of pipelines of the municipal life support systems, the issues of developing the requirements for choosing the material and type of pipes in relation to specific operating conditions of urban water supply systems become very relevant. The reliability and safety of the public water supply have been the main requirements applicable to these systems as the most important components of public health and one of the main priorities of the state social policy [1,2]. Of great importance in providing for the reliability of water pipelines is the expert choice of the pipe material. The paper states that for many years the main pipe materials used in the public water supply of Russian cities have been steel and cast iron. In recent years, ductile iron pipes widely used abroad and in Russia, in particular in the Moscow water supply system, have been competing with steel pipes (among metal ones). The paper presents the information on the condition of the water pipelines in the Russian cities, on the characteristics of ductile iron pipes and their use in soft and subsiding soils.
The state and dynamics of the intellectual infrastructure of technological development of industrial enterprises: methodological tools for assessing sustainability
Authors: Leventsov Valery , Kornienko Alexander , Yakovleva Elena , Drozdov Danila
Published: August 2023

The article presents the results of research in the field of formation of methods of organization of intellectual infrastructure of technological development of industrial enterprises, focused on methodological issues of measuring and assessing its sustainability. The relevance of the research is due to modern trends in the intellectualization of the economy under the influence of technological processes of digitalization, which determine the need for the formation of new infrastructure institutions necessary to solve modern problems of technological development in industry. As a result of this research stage, the structural characteristics and parameters that determine the state and dynamics of the intellectual infrastructure of technological development of industrial enterprises have been clarified, which allowed us to offer methodological tools for assessing the state of stability of the intellectual infrastructure and the prospects for its positive dynamics focused on the digital transformation of business processes of industrial production. Thus, as structural elements that determine the organizational level of the intellectual infrastructure of technological development of industrial enterprises, the following are defined: the level of material resources used in the production of products; the availability of logistics routes; the environmental impact of the results of resource processing, including the cost of disposal of residues; the state of fixed assets. The author’s approach to the assessment of the intellectual infrastructure of technological development of industrial enterprises has been developed, based on the identification of key elements of the studied infrastructure, classification of resource blocks, justification of indicators and factors of resource components that affect the stability of the intellectual infrastructure of technological development. This approach makes it possible to develop and improve methodological tools for analytical assessment of the organizational level of stability of the intellectual infrastructure of technological development, identifying trends in its dynamics, as well as controlling unacceptable deviations.
Economic security of industrial companies in conditions of energy transition
Authors: Evseeva Svetlana , Kasianenko Elena , Miller Maxim , Davidenko Lyudmila
Published: August 2023

Effective management of industrial companies in the conditions of modern challenges contributes to the achievement of tactical and strategic goals of technological development of enterprises. In the theory and practice of industrial economics, a special place is given to environmental management, which includes operational environmental management, investment environmental management, risk management, etc. The concentration of efforts in a certain direction depends on the specifics of the activities of the subjects and the problems that they are facing. In this regard, the system of ensuring the economic security of industrial companies that faces the need to solve the tasks of a planned energy transition is of particular importance. Industrial companies of the energy sector of the world economy were selected as the object of the study. As measures to ensure economic security, the article considers a unique risk management policy, including strategic planning, systematization and risk assessment, as well as managerial control over financial, economic, scientific and technological types of risk. The study revealed that over the past five years, industrial companies have been thoroughly approaching the development of an environmental strategy. The authors identify trends in the technological transformation of the global energy complex, which determine promising areas of technological integration for the development of carbon-neutral energy. The most important direction is the development and implementation of innovations that improve environmental safety, including new technologies for the production of pure hydrogen from natural gas and recycling processes. The conducted research made it possible to identify the scientific and institutional prerequisites for risk management of technological integration and to link them with tools for ensuring economic security.
Aspects of sustainable industrial growth in the face of uncertainty
Authors: Evseeva Oksana , Dubinenko Anastasia , Miller Alexander , Davidenko Lyudmila
Published: August 2023

Sustainable development, as a paradigm of a global scale, is the basis of global development, uniting the efforts of people to improve living conditions and solve environmental problems. Reality shows how vulnerable ecosystems with well-established industrial, logistical, and infrastructural ties have turned out to be, which fail in the face of man-made, geopolitical cataclysms. But, if people can preventively assess the impact of these factors, then environmental problems can carry a destructive effect, which many times exceeds the estimates of leading experts. It turns out that industrial corporations act as the driving force of sustainable development. They are at the center of “ecosystem” relations, while representing a source of potential threats of a technological nature, which is why the activities of industrial companies directly determine the ecological situation of entire regions. In the course of the study, it turned out that increased requirements for the design of complex economic facilities demonstrate in practice the possibility of reducing tension in the regions of their presence. With the support of companies, new production facilities for deep processing of raw materials are being created, the production of high-tech products appears, which is typical for both developed and developing regions. It turned out that industrial activity determines the effectiveness of the development of environmental innovations, and the strategy of low-carbon energy goes through a set of decisions on sustainable development under conditions of uncertainty. It is emphasized that the challenges of the external environment, caused by a combination of factors dependent and independent of the activities of industrial companies, increase the degree of responsibility of decisions made in companies that represent an innovative technological “core”.
Study of the variant of application of pressure type of derivation designed as a pipeline
Authors: Bakshtanin Aleksandr , Zhukova Tatiana
Published: August 2023

Hydropower has become one of the most reliably functioning elements of the energy complex under the economic transformations taking place in Russia. Small hydropower has taken a stable position as a component of the energy sector in many countries of the world. Many small rivers in the Russian Federation form about half of the total volume of the country’s river flow. Experts estimate the energy potential of Russia’s small rivers at 380 billion kWh. Small hydropower plants have advantages, which make this equipment more and more popular. We note the environmental safety of mini hydropower plants - an important criterion considering environmental protection issues. Small hydropower plants have no harmful effect on the properties or quality of water. We can use water areas (where small hydroelectric power plants are installed) for both fishery activities and as a source of water supply for settlements. Small HPPs do not need large bodies of water to operate. They can operate using the energy of small rivers and even streams. The purpose of the article is to study the variant of application of pressure type of derivation designed as a pipeline.
Use of bottom ash in the production of ceramic brick
Authors: Jabbarova Natella , Abdullayeva Maya , Asadova Irada
Published: August 2023

The influence of the addition of ash residues from the processing of solid household waste from the Balakhani Industrial Zone in Baku on the properties of ceramic bricks in the Khirdalan and Karadag regions of Azerbaijan was studied. Ash residues were added in the amount of 10-50% of the mass. The physical properties of ash residues were studied - fractional, granulometric, radiological and toxicological compositions, as well as water absorption of ash bricks at different firing temperatures. The positive role of waste for obtaining wall ceramics with high performance properties was revealed, which corresponds to the regulatory requirements of GOST. It should be noted that the introduction of mineral additives has a positive effect on the characteristics of the ash brick. Among other ash-containing bricks at firing temperatures of 900 and 1100, the highest strength (22 MPa) is observed at 1100 °C with an ash content of up to 10%. As the ash content increases, the compressive strength at 900 °C and 1100 °C decreases.
Studies of the periodicity of the service Volvo excavator service EW 145 b
Authors: Maksudov Z.T. , Mirholikov S.
Published: August 2023

At present, the efficient and economical use of road construction machines in the construction, repair and maintenance of roads is a very urgent task. On this aspect of studying and researching the effective and economical use of newly arriving road equipment, incl. single-bucket excavators of foreign countries, when there is no regulatory documentation for their technical operation, is an urgent task. This study is aimed at studying the technical characteristics and frequency of maintenance of a VOLVO single-bucket excavator EW 145B _ By fuel consumption and machine output.
New dimensions and dead ends in ai development: impact and responsibility of science and higher education
Authors: Zinchenko Viktor , Boichenko Mykhailo , Slyusarenko Olena , Popovych Mykola , Radchenko Lidiia , Iehupov Mykola , Bazeliuk Vasil
Published: August 2023

AI development demonstrates shows excellent results in the performance of individual operations of the intellect, but it fails to simplify the performance of tasks, instead of their creative and complex solution. AI cannot set goals, and it understands their achievement in a pattern, and it cannot create a new pattern of interaction, but it brings the fulfillment of existing such patterns to the point of absurdity. Science and higher education are called to carry out permanent support of AI activities and adjustment of tasks for AI.
Analysis of the use of vector autoregressions in economic forecasting
Authors: Svetunkov S.G.
Published: August 2023

Using vector autoregressions is a promising direction in short-term economic forecasting. They do not simply model the relationship between different factors, but also model the time-distributed relationship of these factors. Vector autoregressions are suitable for modeling complex dynamic economic multifactor processes. The complexity of the problem of estimating coefficients, which increases with the dimensionality of vectors, prevents the widespread use of autoregressions in practice. Vector autoregressions in complex-valued form with the same dimensionality as the modeled vector contain a much smaller number of coefficients. This facilitates the estimation of the coefficients of vector autoregressions. Some problems requiring further investigation arise when using vector autoregressions in complex form. Among them is the problem of selecting the best model. The information criteria used for this purpose limit the variety of vector autoregressions, reducing them to elementary models. The study was supported by the Russian Science Foundation grant No. 23-28-01213, https://rscf.ru/project/23-28-01213.
Mathematical modeling and numerical calculation of an epidemic with medical vaccination in account
Authors: Ziyadullaev Davron , Muhamediyeva Dilnoz , Teshaboyev Mukhammadyahyo , To'ychiev Sherozbek , Kamolov Mirzaakbar O. , Bakhramova Yulduz , Ziyodullaeva Gulchiroy
Published: August 2023

This article describes and analyzes mathematical models of the spread of infectious diseases, on the basis of the considered model, a mathematical model of the spread of epidemics is built, it is studied to what extent receiving medical vaccination affects the spread of infectious diseases in this process, and the mathematical models considered in this paper are compared with others. epidemic models.
Mathematical programming in Mathcad and Mathematica
Authors: Vasileva Natalia , Grigorev-Golubev Vladimir , Evgrafova Irina
Published: August 2023

An article generalizes the long-term work of authors with packages of applied mathematical programs. It discusses and demonstrates the features and methods of solution of mathematical tasks in mathematical package Mathcad and Mathematica: from the simplest ones, included in the set of typical problems of mathematical disciplines for training specialists for shipbuilding, to complex computational tasks and applied problems of professional orientation, which require the construction of a mathematical model and analysis of the results obtained. The examples show the solution of mathematical problems in symbolic form, mathematical studies in the Mathcad and Mathematica environment, and mathematical programming with these packages.
Development of an integration model of scientometric systems for effective knowledge management in Ukrainian universities
Authors: Zinchenko Viktor , Levkulych Vasyl , Popovych Mykola , Bulvinska Oksana , Polishchyk Olena , Lakusha Natalia , Chervona Lesya
Published: August 2023

The article highlights one of the leading goals of scientometric indicators and data in the context of the internationalization of higher education and scientific institutions – the inclusion in the international, global scientific and educational system of the greatest possible number of relevant scientific communities, teams of scientists, researchers and their scientific works, developments, innovations, and rating them according to certain objective indicators. The emergence of scientometric bases (systems, platforms) is a natural phenomenon in the development of society as an attempt to measure something that, on the one hand, is abstract, and, on the other hand, is characterized by certain quantitative features as a result of deep analysis. Scientific research leads to the accelerated development of technologies, therefore, at a certain stage, it became necessary to evaluate, that is, to measure the importance of a scientist’s research contribution to the development of a certain field of research. Since this need was felt in different countries with a relatively small time difference, various scientometric technologies were invented and developed.
Optimization of a coronavirus genus recognition procedure based on the n-gene of prototypic strains
Authors: Chaley Maria , Kutyrkin Vladimir
Published: August 2023

The article offers a solution to the problem of fast and efficient recognition of the coronavirus genus. For this purpose, the authors apply a virus genome targeting method based on the use of a sufficiently short and conserved N-gene of the nucleocapsid protein. Comparison of the codon frequency distributions in the N-gene of the analyzed genome and a set of 67 prototypical strains corresponding to the coronavirus subgenus allows us to recognize the genus of the coronavirus. This paper proposes optimization of the genus recognition of coronavirus by eliminating a significant number of codons from the 64 codons of the genetic code (26 in one case and 57 in the other). The authors achieved 100% genus recognition efficiency in a sample of 2,051 coronavirus genomes from the GenBank database with annotated subgenus in the optimized procedure. The authors also achieved 99% confidence when using the optimized coronavirus genus recognition procedure in a total sample of 3,242 genomes.
Die Fell-Mineralanalyse – Fell als Spiegel der
Gesundheit
Authors: Uhlein Ronja
Published: August 2023

Haben Hunde und Katzen auch „Bad-Hair-Days“? Stumpfes, glanzloses
Fell kann bereits ein Hinweis auf eine unzureichende
Mikronährstoffversorgung sein. Doch Haare besitzen noch viel mehr
diagnostisches Informationspotenzial. Das lässt sich über die
Fell-Mineralanalyse erschließen.
Akzeptanz der Osteopathie bei kleinen Heimtieren
Authors: Stüber Meike
Published: August 2023

Was für mich das Beglückende bei der osteopathischen Behandlung
von kleinen Heimtieren ist? Dass diese als Fluchttiere geborenen Patienten die
Grundintention des behandelnden Osteopathen spüren und von Beginn an
Vertrauen zu ihm entwickeln können. Statt Stress zeigen sie Wohlbefinden
an, wie anhand zweier Fallbeispiele dargelegt werden soll.
Surgical Management of Meningiomas Involving the Torcula, Transverse Sinus, and Jugular Bulb: A Technical Note and Review of the Literature
Authors: Power Robert G. , Lam Fred C. , Whitton Anthony C. , Sharma Sunjay , Kasper Ekkehard M.
Published: August 2023

Meningiomas that invade the confluens sinuum are rare and require extensive preoperative planning. Here, we describe the surgical and radio-oncological management of an aggressive large occipital meningioma invading the superior sagittal sinus, torcula, right and left transverse sinus down to the level of the jugular bulb in a 21-year-old female patient. Details of the surgical approach are presented to highlight the planned staged resection of this tumor at the level of the torcula to initially debulk the lesion while preserving venous outflow through the patent's sinus. Once the tumor fully occluded the confluens, a second-stage en bloc resection ensued. Postsurgical adjuvant radiation therapy was delivered via fractionated external beam therapy which has provided local control of the tumor since. This case is being discussed in the context of the pertinent literature to demonstrate the highly complex interdisciplinary and staged management of partially intravascular meningiomas involving the major venous sinuses.
Flexible hardware concept of pulsed laser deposition for large areas and combinatorial composition spreads
Authors: Lorenz Michael , Hochmuth Holger , von Wenckstern Holger , Grundmann Marius
Published: August 2023

Pulsed laser deposition (PLD) is one of the most flexible physical growth techniques for thin films of functional materials at the research and demonstrator level. We describe here a relatively simple and reliable concept of the PLD hardware that allows both deposition on large areas up to 4 in. diameter and deposition of tailored lateral and vertical composition spreads without time-consuming hardware changes. Different PLD approaches have been implemented in various chambers via specific and correlated computer-controlled movements of the target, substrate, and masks in conjunction with an appropriate target phase composition. The design of the chambers benefits from our long-term experience to find the most reliable solutions for the critical mechanical and high-temperature parts.
Modified gravity: A unified approach to metric-affine models
Authors: Böhmer Christian G. , Jensko Erik
Published: August 2023

The starting point of this work is the original Einstein action, sometimes called the Gamma squared action. Continuing from our previous results, we study various modified theories of gravity following the Palatini approach. The metric and the connection will be treated as independent variables leading to generalized theories, which may contain torsion or non-metricity or both. Due to our particular approach involving the Einstein action, our setup allows us to formulate a substantial number of new theories not previously studied. Our results can be linked back to well-known models, such as Einstein–Cartan theory and metric-affine theories, and also links to many recently studied modified gravity models. In particular, we propose an Einstein–Cartan type modified theory of gravity, which contains propagating torsion, provided our function depends non-linearly on a boundary term. We also can state precise conditions for the existence of propagating torsion. Our work concludes with a brief discussion of cosmology and the role of cosmological torsion in our model. We find solutions with early-time inflation and late-time matter dominated behavior. No matter sources are required to drive inflation, and it becomes a purely geometrical effect.
Synthesis and thermal expansion property of Cr2W3O12 doped with WO3
Authors: Dong Qingchen , Liu Kunlei , Jia Chunchun , Wang Shaowu , Liu Xiansheng , Zhang Weifeng
Published: August 2023

Cr2W3O12, one of the members of the negative thermal expansion family of A2M3O12, is reported to be prepared by the solid-state method with Cr2O3 and WO3, which was impossible before. Here, the synthesis of Cr2W3O12 is carried out by solid-state sintering. The powder mixture of Cr2O3 and WO3 is obtained using Zn(CH3COO)2 · 2H2O as the catalyst. When Zn(CH3COO)2 · 2H2O (0–25 mol. %) is added to the mixture of Cr2O3 and WO3 with 15 and 20 mol. % of excess WO3, much of the Cr2W3O12 is formed especially because of the addition of 10 and 15 mol. % of Zn(CH3COO)2 · 2H2O. For comparison, commercial ZnO is used as an addition, but its catalytic role is much lower than that of Zn(CH3COO)2 · 2H2O. The roles of addition of Zn(CH3COO)2 · 2H2O and excess WO3 are ascribed to compensate the volatility of WO3 and speed up the reaction of Cr2O3 + 3WO3 → Cr2W3O12 by the catalytic action of Zn(CH3COO)2 · 2H2O, respectively. The prepared Cr2W3O12 samples show positive thermal expansion due to the influence of excess WO3.
Potential and motion design of droplets in a wetting-programable nanoporous surface
Authors: Wen I-Chen , Jiang Hong-Ren
Published: August 2023

In this study, we design a wetting-programable method to create a surface channel for droplets. Superhydrophilic channels can be designed and erased reversibly by selectively masking the wetting and prewetting process on superhydrophobic silicone surfaces with microgroove and nanoporous structures fabricated using a micromachining technique. We found that droplets in this flow channel present a complex wetting behavior. The surface that undergoes infiltration by wetting and prewetting transitions from being a superhydrophobic surface to becoming a superhydrophilic surface. To understand the dynamics of droplet exploration, we measured the spreading distance of the droplet’s leading edge and the spontaneous capillary flow (SCF). The final spreading length of the droplet’s leading edge was also recorded. We found that increasing the prewetting volume enhances the final spreading distance of the droplet’s leading edge and the average SCF speed. Prewetting minimizes the apparent contact angle and pinning, promoting superhydrophilicity and increasing the droplet mobility. To further enhance our control over liquid transport, we incorporated vertical vibration as an active approach to regulate the programmed transport of droplets. We observed a substantial extension in the final spreading distance of the droplet’s leading edge. This extension was attributed to the effective overcoming of the pinning phenomena caused by the application of vertical vibration. With the above-mentioned methods, we achieve guided motion and multi-droplet sequence mixing of droplets with the designed channel shapes. Our results suggest how the wetting behavior dynamics of a multi-level structural surface are affected by prewetting liquid and vertical vibration. This provides insight into the wetting mechanism on porous superhydrophobic/superhydrophilic material.
Diffusion in inhomogeneous fluids: Hard spheres to polymer coatings
Authors: van Swol Frank , Douglas Frink Laura J. , Malanoski Anthony P. , Petsev Dimiter N.
Published: August 2023

We investigate diffusion in fluids near surfaces that may be coated with polymer films. We first consider diffusion in hard sphere fluids near a planar hard wall. We specifically consider color diffusion, where hard spheres are labeled A or B but are otherwise identical in all respects. In this inhomogeneous fluid, we consider a surface reaction–diffusion problem. At the left wall, a particle of species A is converted to one of species B upon a wall collision. At the opposing wall, the reverse reaction takes place: B → A. Using molecular dynamics simulation, we study the steady state of this system. We demonstrate that in the homogeneous region, a diffusing particle is subject to an equilibrium oscillatory force, the solvation force, that arises from the interfacial structuring of the fluid at the wall. For the hard sphere/hard wall system, the solvation force can be determined in various ways. We use the solvation force [the potential of mean force (PMF)] to solve the continuum diffusion equation. This provides an adequate and accurate description of the reaction–diffusion problem. The analysis is then extended to consider both color diffusion in the presence of a slowly varying one-body field such as gravity and a more applied problem of diffusion of free species through a surface film consisting of tethered chains. In both cases, the PMF experienced by the free particles is affected, but the diffusion problem can be treated in the same way as for the simpler hard sphere color diffusion case.
Molecular dynamics simulation study on the mass transfer across vapor–liquid interfaces in azeotropic mixtures
Authors: Bråten Vilde , Schaefer Dominik , Stephan Simon , Hasse Hans
Published: August 2023

Mass transfer through fluid interfaces is an important phenomenon in industrial applications as well as in naturally occurring processes. In this work, we investigate the mass transfer across vapor–liquid interfaces in binary mixtures using molecular dynamics simulations. We investigate the influence of interfacial properties on mass transfer by studying three binary azeotropic mixtures known to have different interfacial behaviors. Emphasis is placed on the effect of the intermolecular interactions by choosing mixtures with the same pure components but different cross-interactions such that different azeotropic behaviors are obtained. The molar flux is created by utilizing a non-stationary molecular dynamics simulation approach, where particles of one component are inserted into the vapor phase over a short period of time before the system’s response to this insertion is monitored. From a direct comparison of the density profiles and the flux profiles in close proximity to the interface, we analyze the particles’ tendency to accumulate in the interfacial region throughout the different stages of the simulation. We find that for mixtures with strong attractive cross-interactions, the inserted particles are efficiently transported into the liquid phase. For systems with weak attractive cross-interactions, the inserted particles show a tendency to accumulate in the interfacial region, and the flux through the system is lower. The results from this work indicate that the accumulation of particles at the interface can act as a hindrance to mass transfer, which has practical relevance in technical processes.
A Constructional Account of Verb-Forming Suffixation
Authors: Laws Jacqueline
Published: August 2023

The range of meanings expressed by derivatives formed by the attachment of the four principal verb-forming suffixes - ate, - en, - ify and - ize has been the subject of extensive analysis for over two decades. From a descriptive perspective, the research reported in this volume constitutes the most comprehensive usage-based analysis of verbal derivatives available to date and provides register-based and diachronic comparisons of usage and distribution patterns across corpora of spoken English. The semantic analysis adopts the seven well-established semantic categories of verbal derivatives and extends the set to twenty by including further meaning classes documented in the morphological literature and additional senses that emerged from the contextualized analysis of complex verbs in the datasets. From a theoretical standpoint, the novel approach involves the explicit linking of affix schemas to argument structure constructions, and proposes a unified model of verb-forming suffixation that accounts for the multi-functional characteristics of verbal derivatives, from a constructional perspective.
Stability and instability results for equilibria of a (relativistic) self-gravitating collisionless gas—a review
Authors: Rein Gerhard
Published: August 2023

We review stability and instability results for self-gravitating matter distributions, where the matter model is a collisionless gas as described by the Vlasov equation. The focus is on the general relativistic situation, i.e. on steady states of the Einstein–Vlasov system and their stability properties. In order to put things into perspective we include the Vlasov–Poisson (VP) system and the relativistic VP system into the discussion.
Weyl Fermions and broken symmetry phases of laterally confined 3He films
Authors: Wu Hao , Sauls J A
Published: August 2023

Broken symmetries in topological condensed matter systems have implications for the spectrum of Fermionic excitations confined on surfaces or topological defects. The Fermionic spectrum of confined (quasi-2D) 3He-A consists of branches of chiral edge states. The negative energy states are related to the ground-state angular momentum,

L
z

=
(
N

/

2
)
ℏ

, for

N

/

2

Cooper pairs. The power law suppression of the angular momentum,

L
z

(
T
)
≃
(
N

/

2
)
ℏ
[
1
−

2
3

(
π
T

/

Δ

)
2

]

for

0
⩽
T
≪

T
c

, in the fully gapped 2D chiral A-phase reflects the thermal excitation of the chiral edge Fermions. We discuss the effects of wave function overlap, and hybridization between edge states confined near opposing edge boundaries on the edge currents, ground-state angular momentum and ground-state order parameter of superfluid 3He thin films. Under strong lateral confinement, the chiral A phase undergoes a sequence of phase transitions, first to a pair density wave (PDW) phase with broken translational symmetry at

D

c
2

∼
16

ξ
0

. The PDW phase is described by a periodic array of chiral domains with alternating chirality, separated by domain walls. The period of PDW phase diverges as the confinement length

D
→

D

c
2

. The PDW phase breaks time-reversal symmetry, translation invariance, but is invariant under the combination of time-reversal and translation by a one-half period of the PDW. The mass current distribution of the PDW phase reflects this combined symmetry, and originates from the spectra of edge Fermions and the chiral branches bound to the domain walls. Under sufficiently strong confinement a second-order transition occurs to the non-chiral ‘polar phase’ at

D

c
1

∼
9

ξ
0

, in which a single p-wave orbital state of Cooper pairs is aligned along the channel.
Machine learning and UAV path following identification algorithm based on navigation spoofing
Authors: Ma Chao , Qu Zhi , Li Xianbin , Liu Zongmin , Zhou Chao
Published: August 2023

With advances in navigation technology, unmanned aerial vehicles (UAVs) have become widely available to all sections of society. Given the potential hazards of UAVs, as seen from their use in the Russia–Ukraine war and security incidents at London and Baghdad airports, counter-UAV technology is receiving unprecedented attention. This paper describes a method for taking control of a UAV indirectly by navigation spoofing and luring it to a designated area from which it can be neutralized. Our contributions are threefold: first, we analyze the limitations of the traditional state estimation and control model for UAV navigation based on the integration of the Global Navigation Satellite System and Inertial Navigation System. Second, we propose a particle hypothesis and planning model that is insensitive to the particular UAV navigation system, and decompose the UAV navigation spoofing process into two steps: identification and planning. Finally, to overcome the poor heading angle prediction accuracy of unary polynomial regression, we propose a support vector regression algorithm that improves the prediction accuracy from 1.5° to 1.01° under navigation spoofing. Experimental results using the proposed navigation spoofing method prove that machine learning offers significant advantages in modeless identification.
Single-source UDA for privacy-preserving intelligent fault diagnosis based on domain augmentation
Authors: Zhao Xiaoping , Ma Mengyao , Xue Xingan , Peng Peng
Published: August 2023

In practical applications of fault diagnosis, several factors, including fluctuations in load, changes in equipment condition, and environmental noise effects, could cause a classifier that’s been trained on the source domain to be ill-suited for matching data from the target domain. Unsupervised domain adaptation techniques have been developed to tackle this issue, but they typically demand access to fully labeled source domains, ignoring concerns of privacy regarding source domain data. Therefore, we consider a new research scene for source-free unsupervised domain adaptation (SFUDA), which exclusively relies on a source model trained on source domain sample without requiring access to fully labeled source domain data. This paper introduces a SFUDA approach that utilizes knowledge distillation (KD), which involves two stages: (1) generalizing the source model by applying domain augmentation techniques and LS methods that enhance the model’s potential to enhance its generalization capability; (2) adapting the target model using a KD framework to achieve knowledge migration; and in addition, mutual information structure regularization is added to consider the internal data structure, thus enhancing the model’s adaptability. To evaluate the efficacy of our approach, we perform experiments on two datasets—the Case Western Reserve University dataset and the Paderborn University dataset, comprising 24 transfer tasks. Our experiments demonstrate the effectiveness of the domain augmentation technique, mutual information regularization, and the proposed method.
Electric field simulation of multi-needle water bath electrospinning and the structural properties of SCN/PAN micro/nanofiber composite yarns
Authors: Fan Mengjing , Yue Xinyan , Wang Xiaohu , Fan Senlin , Hong Jianhan , Han Xiao , Zhao Xiaoman
Published: August 2023

Multi-needle water bath electrospinning is one of the most efficient methods used to prepare micro/nanofiber composite yarns. The nanofiber structure can be targeted and regulated to obtain high-performance composite yarns. To explore the effect of the receiving distance on the structure and properties of micro/nanofiber composite yarns, polyacrylonitrile nanofibers were uniformly coated on silver-coated nylon yarn via a four-needle continuous water bath electrospinning method. The electric field distribution at different receiving distances was simulated by ANSYS finite element analysis software, and the effects of electric field distribution on the structure and properties of the micro/nanofiber composite yarns were studied. The results indicated that the peak electric field intensity appeared at the tip of the needles and decreased with the increase in the receiving distance. The receiving distance was constant, and the field intensity was lower when the direction of the centerline of the needle tip was farther away from the tip; however, the field intensity at the conductive core yarn was higher than that in the surrounding area (small spikes). The average field intensity of the small spikes at 180 mm was only 1/4 of that at 80 mm. When the receiving distance increased within a certain range (100∼140 mm), the nanofibers had a smooth surface and good separation, their diameters decreased continuously and the porosity changed inversely. With a further increase in the receiving distance, the nanofibers gradually bonded, their diameter increased and the porosity showed the opposite trend. The coating rate of the nanofibers showed a decreasing trend, and the mechanical properties of the micro/nano composite yarns were improved. When the receiving distance was 100 mm, the porosity reached 38.94%, and the breaking force, breaking elongation and breaking strength were 13.71 ± 1.36 cN, 22.76 ± 6.62% and 0.15 ± 0.02 cN·dtex−1, respectively. Upon consideration of all the above factors, the receiving distance of 100 mm is appropriate.