bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sub-gap Fano resonances in a topological superconducting wire with on-site Coulomb interactions
Authors: Stefański Piotr 
Published: August 2021

Abstract
We consider theoretically a 1D-semiconducting wire with strong Rashba interaction in proximity with s-wave superconductor, driven into topological phase by external magnetic field. Additionally, we take into account on-site Coulomb interactions inside the wire. The system is modelled by a tight binding Hamiltonian with Rashba hopping term and induced s-wave superconductivity. Calculations are performed utilizing recursive Green’s function method, and Coulomb interactions are treated selfconsistently within Hubbard I approximation. For the Hubbard levels residing within p-wave superconducting gap, particle–hole symmetric four-resonance structure develops in the density of states, apart from Majorana resonance. One pair of particle–hole symmetric resonances is created by the discrete II-Hubbard levels of the particular site, and the second pair of Hubbard sub-bands originates from recursive summation over the sites of the wire. Quantum interference between both types of pairs of states creates in-gap charge-conjugated Fano resonances with opposite asymmetry factors. We demonstrate that when quantum interference is dominated by two-particle tunneling, the Majorana resonance is strongly diminished, while it is not altered when single-particle tunneling dominates in interference process. We also discuss some consequences for experimental distinction of true Majorana states, and show that on-site Coulomb interactions support the appearance of topological phase.
Design and fabrication of networks for bacterial computing
Authors: van Delft Falco C M J M , Sudalaiyadum Perumal Ayyappasamy , van Langen-Suurling Anja , de Boer Charles , Kašpar Ondřej , Tokárová Viola , Dirne Frank W A , Nicolau Dan V 
Published: August 2021

Abstract
Non-deterministic polynomial (NP-) complete problems, whose number of possible solutions grows exponentially with the number of variables, require by necessity massively parallel computation. Because sequential computers, such as solid state-based ones, can solve only small instances of these problems within a reasonable time frame, parallel computation using motile biological agents in nano- and micro-scale networks has been proposed as an alternative computational paradigm. Previous work demonstrated that protein molecular motors-driven cytoskeletal filaments are able to solve a small instance of an NP complete problem, i.e. the subset sum problem, embedded in a network. Autonomously moving bacteria are interesting alternatives to these motor driven filaments for solving such problems, because they are easier to operate with, and have the possible advantage of biological cell division. Before scaling up to large computational networks, bacterial motility behaviour in various geometrical structures has to be characterised, the stochastic traffic splitting in the junctions of computation devices has to be optimized, and the computational error rates have to be minimized. In this work, test structures and junctions have been designed, fabricated, tested, and optimized, leading to specific design rules and fabrication flowcharts, resulting in correctly functioning bio-computation networks.
Measurements of Fast Transitions at a Reversible Pump Turbine Model in Closed Loop Test Rig
Authors: Junginger J , Kirschner O , Riedelbauch S 
Published: August 2021

AbstractIt is common practice to experimentally investigate the performance characteristics of hydraulic fluid machinery in power plants with steady-state operating points by scaled homologous model machines in closed-loop test rigs. In this case, the piping of the main water conduit from the power plant and the test rig plays a minor role. However, for studies of operating transient, e.g. load rejection, the influence of the weak compressibility of water in the pipes is considered by 1-D water hammer analyses. Due to differences in the main water conduit between the power plant and the test rig, the test rig is specifically controlled by new procedures to replicate the relevant conditions at the fluid machine in the test rig under similarity conditions.The results of this newly developed method for specific control of the test rig for operating transients are presented and successfully validated on a closed-loop experimental system. In future, suitable instrumented model machines then allow the measurement of dynamic pressures or even strains in and on machine components in order to elaborate, as a goal, the influence of different operating transients on the service life of machine components. Furthermore, these experimental data can also be used to validate Computational Fluid Dynamics (CFD) and Finite Element Analyses (FEA) simulations.
Experimental Study of Break-off Frequency in Cavitation Disappearance Phenomenon on NACA16-012 Hydrofoil
Authors: Sugaya Koki , Ochiai Takaho , Okajima Junnosuke , Iga Yuka 
Published: August 2021

Abstract
Under the specific angle of attack on NACA16-012 hydrofoil, generated cavitation suddenly disappears even in the low cavitation number condition in which cavitation normally develops. This cavitation disappearance phenomenon was confirmed to be unique to NACA16-012 hydrofoil in our previous research. It was experimentally confirmed that cavitation disappearance phenomenon occurs in a transient cavitation condition where the sheet cavity is periodically broken off and the cloud cavity is released. In the previous study, it was predicted that there is the frequency band in which sheet/cloud cavitation cannot exist and cavitation disappearance phenomenon occurs. In this study, the break-off frequency of NACA16-012 hydrofoil was experimentally investigated and relationship between the break-off frequency and cavitation disappearance phenomenon was considered. The pressure fluctuation was measured with the pressure transducer downstream reagion and the dominant frequency was estimated by the frequency analysis. As the results, cavitation disappearance phenomenon was confirmed at angles of attack of 6° and 7°. There was the region increasing the break-off frequency according to decreasing of cavitation number at angles of attack 6° to 12°. It means that the break-off frequency of NACA16-012 hydrofoil has unusual characteristics. When the break-off frequency was expressed by the Strouhal number, it was found that the Strouhal number took each same value immediately just before and after cavitation disappearance phenomenon in decompression experiment. It was suggested that the break-off frequency was related to cavitation disappearance phenomenon.
Maximum Likelihood Identification of Cavitation Instabilities in Axial Inducers
Authors: Tumminia Matteo , Valentini Dario , Pace Giovanni , Hadavandi Ruzbeh , Torre Lucio , Pasini Angelo , d’Agostino Luca 
Published: August 2021

Abstract
The article illustrates the application of maximum likelihood estimation to the identification of cavitation instabilities in axial inducers from the unsteady pressure readings measured on the impeller casing. The typical triangular pressure distribution in the blade channels of the impeller is parametrized and modulated in time and space in order to theoretically reproduce the expected pressure generated by known forms of cavitation instabilities (cavitation auto-oscillations, n-lobed sub/super-synchronous rotating cavitation, higher-order surge/rotating cavitation modes). The Fourier spectra of the theoretical pressure so obtained in the rotating frame are transformed in the stationary frame and fitted by maximum likelihood estimation to the auto-correlation of the pressure measurements on the inducer casing. Each form of instability generates a characteristic spectral distribution of side bands in addition to its fundamental frequency. The identification makes use of this information for effective discrimination of simultaneous flow oscillations with significantly different intensities and partially overlapping frequencies. The method returns the estimates of the model parameters and their standard errors, allowing for both recognition of the forms of instabilities occurring in the inducer and assessment of the statistical significance of the results.
Relationship between statistical shift of the Fermi level and activation energy of conductivity in phase-change materials
Authors: Vorobyov Y V , Ermachikhin A V , Trusov E P 
Published: August 2021

Abstract
The non-Arrhenius behaviour of conductivity of phase-change materials is analysed in terms of the statistical shift of Fermi level. To show this connection, a simplified model for the density of states in a phase-change material is proposed to simulate the temperature dependence of the Fermi level. Comparison of the temperature dependence of conductivity of Ge2Sb2Te5 with the simulation results allowed estimating the position of defect levels in the bandgap.
Influence of polyaniline on the electrophysical properties of lead-free ceramics
Authors: Glazunova E V , Verbenko I A , Andryushin K P , Yurasov Yu I , Reznichenko L A 
Published: August 2021

Abstract
The effect of polyaniline additives on the dielectric and piezoelectric properties of a composite based on a multi-component system of sodium-potassium niobate was studied in the paper. The behavior of dielectric characteristics, electromechanical and piezoelectric properties of the system was studied. The critical concentration of polyaniline influencing the formation of an electromechanical connection between ferroactive inclusions and piezoelectric properties was determined.
The dependence of mechanical properties of Al-6101 alloy on geometry of the samples with a groove during tensile tests
Authors: Magomedova D K , Gunderov D V , Mavlutov A M 
Published: August 2021

Abstract
This paper presents data on the mechanical properties of 6101 aluminum alloy during tensile tests of cylindrical samples with a groove of various geometries. The values of ductility, yield, changes in geometry of the samples are provided. It was also shown that the parameters of ductility and strength depend on geometry of the sample for tensile tests.
Modeling for manufacturability of the design of parts with concentrators by the method of photoelasticity
Authors: Yagyaev Elmar , Shron Leonid , Meniuk Dmitriy 
Published: August 2021

Abstract
The article provides a methodology for the experimental determination of the concentration coefficients ασ and the gradients of the principal stresses. The effectiveness of the experimental method of photoelasticityis shown for studying the stress-strain state of parts of complex shape in the presence of stress concentrators, as well as for solving problems of brittle strength by methods of linear fracture mechanics.
Modern microbiological methods of phytosanitary monitoring
Authors: Nikolenko M V , Trigub V V , Enotkaeva O V 
Published: August 2021

Abstract
In this work, an express method is proposed, based on the registration of changes in the impedance of the nutrient medium, which occurs under the influence of the processes of growth and vital activity of microorganisms in the sample under study. The research was carried out on the analyzer “BioTrack 4250”. This device is highly productive, as it examined 21 samples simultaneously for several hours. For testing the indirect impedance technique, fodder, medicinal and weed plants were selected as objects of study. The sanitary condition of the samples was assessed by the total mesophyll aerobic and optional-anaerobic microorganisms (QMA&OAMO), sanitary-indicative bacteria of the E. coli group, and the number of yeast fungi. It was proved that plants collected in the central part of the city of Tyumen with a high population density had high QMA&OAMO indices and high indicators of contamination with Candida sp. On the contrary, fodder plants growing in the Tyumen region were characterized by high indices of sanitary-indicative microorganisms, which indicated an increased risk of feed contamination. Thus, in contrast to the classical methods, the proposed method allows obtaining objective results, shortening the research time, reducing labor costs, and significantly reducing the cost of analysis.
Nanostructured wear-resistant coating for the composite turning inserts
Authors: Litvinov Artem E , Yu Buz’ko Vladimir , Ivanin Sergei N 
Published: August 2021

Abstract
The article presents the results of study of microstructural and strength properties of developed nanostructured wear-resistant high-hardness coating with high strength characteristics, resistance to shock and vibration loads on the surface of cutting inserts for instrumental and high-speed steel turning treatment. The specificity of the turning operating conditions of the composite cutting tool inserts shows that the cutting inserts working surface should have such characteristics as high hardness, strengths, increased vibration resistance, resistance dynamic loads and thermal shock, as well as increased wear resistance. Therefore, one of the ways to solve this problem proposed in the report is applying a wear-resistant hard oxide phase nanostructured coating on the surface of the cutting edge of the composite cutting inserts. Technological modes were selected for the wear-resistant hard protective coating which provides high microhardness due to the nanostructure by magnetron sputtering deposition of the developed compositions that have high adhesion to substrates made of composite cutting turning inserts. The results are shown on the example of high-speed turning of 30KhGSA by using composite turning inserts with developed nanostructured wear-resistant hard protective coating.
Plasma-chemical deposition of gallium oxide layers by oxidation of gallium in the hydrogen-oxygen mixture
Authors: Mochalov L A , Logunov A A , Kudryashov M A 
Published: August 2021

Abstract
Gallium oxide is an ultra wide band gap (the width of the band gap is 4.85 eV) transparent semiconducting oxide, that nowadays attracts much attention of scientists and manufacturers. However, the main obstacle, preventing from its massive commercial implementation, is the lack of technological methods to its production; it is supposed to be cheap, reproducible, and scalable. In this work we are developing a novel plasma-chemical method of Ga2O3 thin films’ synthesis; according to this method only high-purity elemental gallium was used as the source of gallium delivered by the hydrogen flow into the plasma discharge zone, where the interaction with oxygen took place. The properties of the solid phase obtained in the conditions of heteroepitaxial growth were studied depending on the experimental parameters.
Justification of impregnation modes for wood
Authors: Gazizov A M , Samosenko E G , Popova E V 
Published: August 2021

Abstract
One of the most significant disadvantages of wood materials is increased combustibility. Therefore, the problem of reducing the combustibility of wood materials is relevant. The article describes an experimental study of impregnation of wood using biopiren MIG-09, which is a hybrid composition on a salt basis with the addition of functional substances of non-salt nature, at different temperature regimes. Two stages of the study were chosen for the experiment. The optimum temperature regimes for different methods of applying the composition to increase the fire resistance of wood were established experimentally. Also fire tests were carried out to analyze the degree of penetration of the solution.
Non-autoclave ash-filled porous concrete for bearing and enclosing structures
Authors: Belov V V , Kuliaev P V 
Published: August 2021

Abstract
Non-autoclaved ash-porous concrete (NAAC), which is enlightened in the article facilitates the reduction of the cost of construction of large-space engineering structures and multi-storey buildings. It is possible due to eliminating the use of expensive porous aggregates, which involves using the porization effect of the concrete mixture in the manufacture of such structures, as well as using of waste from local industry. It also reveals the advantages of using cellular concrete of non-autoclaved hardening, which has a low energy consumption. Such material is showed to be of use in production of load-bearing and enclosing reinforced concrete structures.
New polymorphic varieties of graphyne formed on the basis of 5-7b graphene: Ab initio calculations
Authors: Mavrinskii V V , Belenkov E A 
Published: August 2021

Abstract
The crystal and electronic structure of 16 new polymorphic varieties of sp+sp2 graphyne layers was calculated by the density functional theory method in the gradient approximation. The primary structure of the graphyne layers was constructed by replacing the interatomic bonds in the graphene layers 5-7b with carbyne chain fragments. Ab initio calculations have shown that out of 29 modeled structures only sixteen are stable: 14 β-type layers and one α- and γ-type layer each. During optimization 13 graphyne layers were transformed into graphene layers or into graphyne layers with a smaller relative number of sp-hybridized atoms. The electronic properties of most of the new graphyne layers are metallic, since the density of electronic states at the Fermi energy level for them is different from zero. There are forbidden zones in the electronic structure of the seven layers, but their value is small and varies from 0.05 to 0.20 eV.
Comparison of sequential and circular scanning thermal fields and their influence on microstructure of Alnico alloy produced by laser powder bed fusion
Authors: Kuznetsov P A , Shakirov I V , Mozhayko A A , Zhukov A S , Bobyr V V 
Published: August 2021

Abstract
Residual stress create deformations and stress in additive structures that lead to geometry deviations of created elements of 3D models and defects as pores and cracks that occur in construction process. Our work rests upon theoretical and experimental approach to the study. The main objective is to compare thermal fields with the microstructure of samples and to establish relationship between laser powder bed fusion (LPBF) modes and the structure of the samples to be created. 3D finite element method (FEM) is used for macroscopic modeling to assess the effect of thermal fields on the microstructure of Alnico alloy. Comparison of the temperature fields with the microstructure of samples made by LPBF showed that the type of scanning (both bidirectional and circular) had a strong influence on the distribution of the thermal fields and, accordingly, on the microstructure of the samples made by LPBF.
The Simulative Optimization of Aerosol Micro Atomizer for Pulmonary Delivery Device
Authors: Zhang Zhen , Yang Wenhui , Chen Jun , Liu Yujie , Wang Xudong 
Published: August 2021

Abstract
The present study investigated the design optimization of aerosol micro atomizer for liquid pulmonary device. Pulmonary delivery device with a micro atomizer at the tip is commonly used to penetrate into a small animal’s trachea, and directly quantitatively spray the infected dosing aerosol samples to animal’s lung. In order for no damage to animal’s trachea, a long capillary with a diameter of 0.5-0.6 mm is used for flow diversion. Therefore, the swirl atomizer size of the head is required to be adequately tiny with uniformity and penetration of aerosol spray. Due to structural limitation without adequate rotational space, it is highly challenging to provide the fine atomization with high quality. Therefore, based on the simulation analysis in Simspray software, the optimization design of the micro atomizer is conducted, aiming to improve the atomization quality with a certain spray angle. Parametric study on swirl atomizer structure, including swirl pitch, nozzle diameter and size of swirl channel, realized an excellent combination of parameters to meet requirement of fine spray. The experiment testifies that the 3-5μm aerodynamic diameter of droplets in spray is available.
The Influence of Dusty Size Distribution Model on Propagation of Electromagnetic Waves in Inhomogeneous Plasma Sheath
Authors: Zhang Jie , Zhang Guodong , Zhao Shanchao , Han Bing 
Published: August 2021

Abstract
In this paper, a linear distribution model, a double exponential distribution model and a hyperbolic number distribution model are developed, and the effect of dust particle size distribution on its attenuation coefficient is considered. On this basis, the transmission characteristics of electromagnetic waves in dusty plasma under different electron density distribution models are investigated. The attenuation coefficients of electromagnetic waves are derived in detail using analytical methods, and the effects of electromagnetic wave frequency, particle collision frequency and dust particle density on the transmission characteristics of electromagnetic waves are discussed. The results show that the choice of terahertz wave as the carrier wave and the appropriate change of particle collision frequency can improve the attenuation of electromagnetic waves. In summary, the relevant research can provide some theoretical references for propagation science.
A Stochastic Volatility Model with Mean-reverting Volatility Risk Premium
Authors: Peng Ke , Xun Ziying , Hu Mingzhu 
Published: August 2021

Abstract
The volatility risk premium (VRP) has long been the core issue in option pricing and risk management. The VRP is usually defined as a linear function of volatility which ignores the time-varying property of VRP and limits the degree of freedom of the model. In this paper, we adopt a CIR process in the stochastic volatility model (VRP-CIR-SV) to incorporate the mean-reverting and time-varying properties of VRP. We show that the decomposition of VRP is consistent to investor’s behaviour. Our Monte Carlo simulation results show that, compared with the traditional linear VRP model, the VRP-CIR-SV model can better depict the rich shapes of implied volatility curve. Our paper innovatively models the time-varying VRP with mean-reverting property, which may provide new thoughts for VRP estimation.
Simulation Design and Optimization of UV-LED Water Purification System Based on Fluid Dynamics and Radiometry
Authors: Liu Rui , Zhou Chao , Lu Rucong , Zhang Jiang 
Published: August 2021

Abstract
In this paper, we established the flow field and radiation intensity distribution models of water purification equipment based on computational fluid dynamics (CFD) technology and radiometric principles. From geometric shape to hydraulic state and radiation intensity distribution, we fully simulated the real scene of the Ultraviolet LED (UV-LED) water purification system, and provided the reliable data for the UV-LED in the water purification field. Compared with mercury lamp, UV-LEDs have a more flexible layout to produce a variety of radiation intensity distributions. UV dose (the product of radiation intensity over time) is an important indicator. We used a discrete phase model (DPM) to track the path of microbial particles, and found that the residence time of microorganisms in different parts of the model was different. By optimizing the UV-LED layout, the radiation intensity was increased in the sites where the microbes resided longer. The results show that we can improve the efficiency of the water purification equipment by simply adjusting the UV-LED layout without increasing the power, and make the UV dose achieves the national standard.