bluuebunny/crossref_metadata_2025 huggingface dataset:
Extracting optical absorption characteristics from semiconductor nanowire arrays
Authors: Kohandani Reza , Saini Simarjeet S
Published: May 2022

A method based on extraction of the effective absorption coefficient using Beer–Lambert’s law on simulated transmissions is used to understand the optical absorption characteristics of semiconductor nanowire arrays. Three different semiconductor nanowire arrays, viz. silicon (Si), gallium arsenide (GaAs) and amorphous silicon (a-Si), are evaluated using the method. These semiconductors were chosen since two of them have similar real parts of the refractive index in the visible range, while the other two have comparable imaginary parts of the refractive index in the visible range. We examine the roles of the real and imaginary parts of the refractive index in enhancing the absorption characteristics in the nanowire arrays due to the excitation of radial and photonic Bloch modes. We observe that high absorption peaks at modal resonances correspond to the resonance peaks in reflections from the nanowire–air interface. Further, the wavelengths of these two peak resonances are slightly detuned according to the Kramers–Kronig relation for an oscillator system. The study confirms that the resonance wavelengths of radial HE modes are diameter and refractive index dependent. The study extends the understanding to the absorption characteristics due to the excitation of the photonic Bloch modes caused by near-field coupling. Excitation of Bloch modes leads to increased absorption and quality factor as compared to only radial mode excitation. We also conclude that the imaginary part of the refractive index of the semiconductor, influence the diameters at which Bloch modes are excited for a given lattice spacing. We observe that semiconductors with a higher bulk value of absorption coefficient need to be ordered more densely in the nanowire array to be able to excite the photonic crystal modes within the array. Interestingly, we see that for Si, GaAs and a-Si arrays with an equal diameter of 80 nm and lattice spacing of 400 nm, the peak absorption is almost the same, even though GaAs and a-Si are highly absorptive materials compared to Si. Thus, both radial and Bloch mode excitations can be used to design absorption profiles in a semiconductor nanowire array.
Portable, desktop high-field magnet systems using bulk, single-grain RE–Ba–Cu–O high-temperature superconductors
Authors: Tsui Y , Moseley D A , Dennis A R , Shi Y-H , Beck M R , Cientanni V , Cardwell D A , Durrell J H , Ainslie M D
Published: May 2022

Bulk high-temperature superconducting materials can trap magnetic fields up to an order of magnitude larger than conventional permanent magnets. Recent advances in pulsed field magnetization (PFM) techniques now provide a fast and cost-effective method to magnetize bulk superconductors to fields of up to 5 T. We have developed a portable, desktop bulk high-temperature superconducting magnet system by combining advanced PFM techniques with state-of-the-art cryocooler technology and single-grain, RE–Ba–Cu–O [(RE)BCO, where RE is a rare-earth element or yttrium] bulk superconducting materials. The base temperature of the system is 41 K and it takes about 1 h for the system to cool down to 50 K from room temperature. A capacitor bank, combined with easily-interchangeable, solenoid- or split-type copper magnetizing coils and an insulated bipolar gate transistor acting as a high-speed switch, allows magnetic pulses to be generated with different pulse profiles. The system is capable of trapping magnetic fields of up to ∼3 T. In this work, we report the results of the magnetization of a range of single-grain Y–Ba–Cu–O, Eu–Ba–Cu–O and Gd–Ba–Cu–O (GdBCO), bulk superconducting discs using this system. A higher trapped field was recorded using a split coil incorporating iron yokes at temperatures of 65 K and above, whereas at lower temperatures, a higher trapped field was obtained using the solenoid coil. The GdBCO sample achieved the highest trapped field for both single-pulse (SP) and two-stage-multi-pulse (TSMP) methods using the solenoid coil. Maximum trapped fields of 2.26 T at 55 K and 2.85 T at 49 K were recorded at the centre of the top surface of the GdBCO sample for the SP and TSMP methods, respectively. The PFM process is substantially an adiabatic process so, therefore, the thermal contact between the sample and sample holder is of critical importance for cooling the bulk sample during application of the pulse. The design of the sample holder can be modified easily to enhance the thermal stability of the sample in order to achieve a higher trapped field.
Steady states of Λ-type three-level systems excited by quantum light with various photon statistics in lossy cavities
Authors: Rose H , Tikhonova O V , Meier T , Sharapova P R
Published: May 2022

The interaction between quantum light and matter is being intensively studied for systems that are enclosed in high-Q cavities which strongly enhance the light–matter coupling. Cavities with low Q-factors are generally given less attention due to their high losses that quickly destroy quantum systems. However, bad cavities can be utilized for several applications, where lower Q-factors are required, e.g., to increase the spectral width of the cavity mode. In this work, we demonstrate that low-Q cavities can be beneficial for preparing specific electronic steady states when certain quantum states of light are applied. We investigate the interaction between quantum light with various statistics and matter represented by a Λ-type three-level system in lossy cavities, assuming that cavity losses are the dominant loss mechanism. We show that cavity losses lead to non-trivial electronic steady states that can be controlled by the loss rate and the initial statistics of the quantum fields. We discuss the mechanism of the formation of such steady states on the basis of the equations of motion and present both analytical expressions and numerical simulations for such steady states.
Nonequlibrium magnetic features in a mixed spin (2, 5/2) Ising system driven by the external oscillating magnetic field by path probability method
Authors: Gençaslan Mustafa , Keskin Mustafa
Published: May 2022

Utilizing the path probability method, we investigated nonequilibrium magnetic features in a mixed spin (2, 5/2) Ising model Hamiltonian composed of bilinear and crystal-field interactions in the presence of an external oscillating magnetic field. We numerically solved the time dependence of average magnetizations to find the phases in the system. We examined the dynamic magnetizations to obtain dynamic phase transition (DPT) temperatures, the nature of the DPTs, and phases in the system. The dynamic phase diagrams (DPDs) were constructed in reduced temperature and the amplitude of oscillating magnetic field plane for various interaction parameters. We observed that the system gives very rich and interesting topological behaviors of DPDs, such as up to two dynamic tricritical points, six critical end points, a double critical end points, a zero-temperature critical point, one inverse critical end point and a quadruple point depending on interaction parameters. The system also exhibits paramagnetic, six distinct ferrimagnetic and three different nonmagnetic phases as well as up to eleven different mixed or hybrid phases. In addition, the system exhibits the reentrant behavior.
NANOGrav signal and LIGO-Virgo primordial black holes from the Higgs field
Authors: Yi Zhu , Zhu Zong-Hong
Published: May 2022

We show that the NANOGrav signal can come from the Higgs
field with a noncanonical kinetic term in terms of the scalar
induced gravitational waves. The scalar induced gravitational waves
generated in our model are also detectable by space-based
gravitational wave observatories. Primordial black holes with
stellar masses that can explain LIGO-Virgo events are also produced.
Therefore, the NANOGrav signal and the BHs in LIGO-Virgo events may
both originate from the Higgs field.
Hybrid fiber laser integrating fast and slow active media for accurate synthesis of high-energy arbitrary optical waveforms by cavity dumping
Authors: Nyushkov Boris , Ivanenko Aleksey , Smirnov Sergey
Published: May 2022

We demonstrate the possibility of the accurate direct laser synthesis of high-energy arbitrary optical waveforms by the programmable driving of partial cavity dumping in a specific continuous-wave fiber laser. To this effect we have developed an original hybrid laser configuration which integrates two different active media. The first medium, a semiconductor optical amplifier (SOA), acts as a saturated lumped preamplifier. It features a relatively fast (sub-nanosecond) gain recovery, and thus effectively suppresses the intracavity power fluctuations induced by cavity dumping. The second active medium, an erbium-doped fiber amplifier (EDFA), acts mainly as a booster amplifier. This distributed inertial amplifying medium effectively accumulates pump energy, thereby providing an enhancement of output energy upon cavity dumping. Our simple proof-of-concept laser setup has allowed the synthesis of nanosecond arbitrary optical waveforms with an energy up to 40 nJ and arbitrarily tunable repetition rate. The proposed combination of a slow (EDFA) and fast (SOA) amplifying stages prevents the laser from strong relaxation oscillations and power flux fluctuations which essentially restrict cavity dumping in conventional rare-earth-doped fiber lasers. The applied two-stage intracavity spectral filtering ensures spectral purity of a rather narrowband (⩽0.1 nm) laser output. For the purpose considered, the integrated SOA-EDFA laser configuration is preferable to a conventional architecture ‘master oscillator—power amplifier’ whose nonlinear gain can obstruct the accurate synthesis of high-energy optical waveforms.
Agile femtosecond synchronizable laser source from a gated CW laser
Authors: Renard William , Chan Clément , Dubrouil Antoine , Lhermite Jérôme , Santarelli Giorgio , Royon Romain
Published: May 2022

In this letter we demonstrate agile femtosecond pulse generation with a widely tunable repetition rate (10–100 MHz) from a continuous wave laser diode optically gated by a Mach–Zehnder electro-optic intensity modulator. Initial sub-50 ps pulses are strongly spectral broadened (>5 nm) by self-phase modulation in a polarization maintaining single-mode fiber. A tunable optical pulse train with pulse durations of a few hundred femtoseconds is obtained using a simple fixed grating compressor, thanks to spectral broadening saturation phenomena. The source is easily synchronized with low timing jitter using an external clock signal.
Two-dimensional Modeling of the Tearing-mode-governed Magnetic Reconnection in the Large-scale Current Sheet above the Two-ribbon Flare
Authors: Zhang Yining , Ye Jing , Mei Zhixing , Li Yan , Lin Jun
Published: May 2022

We attempt to model magnetic reconnection during the two-ribbon flare in a gravitationally stratified solar atmosphere with the Lundquist number of S = 106 using 2D simulations. We found that the tearing mode instability leads to inhomogeneous turbulence inside the reconnecting current sheet (CS) and invokes the fast phase of reconnection. Fast reconnection brings an extra dissipation of magnetic field which enhances the reconnection rate in an apparent way. The energy spectrum in the CS shows a power law pattern and the dynamics of plasmoids govern the associated spectral index. We noticed that the energy dissipation occurs at a scale l
ko of 100–200 km, and the associated CS thickness ranges from 1500 to 2500 km, which follows the Taylor scale l

T
= l
ko
S
1/6. The termination shock (TS) appears in the turbulent region above flare loops, which is an important contributor to heating flare loops. Substantial magnetic energy is converted into both kinetic and thermal energies via TS, and the cumulative heating rate is greater than the rate of the kinetic energy transfer. In addition, the turbulence is somehow amplified by TS, in which the amplitude is related to the local geometry of the TS.
How to successfully classify EEG in motor imagery BCI: a metrological analysis of the state of the art
Authors: Arpaia Pasquale , Esposito Antonio , Natalizio Angela , Parvis Marco
Published: May 2022

Objective. Processing strategies are analyzed with respect to the classification of electroencephalographic signals related to brain-computer interfaces (BCIs) based on motor imagery (MI). A review of literature is carried out to understand the achievements in MI classification, the most promising trends, and the challenges in replicating these results. Main focus is placed on performance by means of a rigorous metrological analysis carried out in compliance with the international vocabulary of metrology. Hence, classification accuracy and its uncertainty are considered, as well as repeatability and reproducibility. Approach. The paper works included in the review concern the classification of electroencephalographic signals in motor-imagery-based BCIs. Article search was carried out in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses standard and 89 studies were included. Main results. Statistically-based analyses show that brain-inspired approaches are increasingly proposed, and that these are particularly successful in discriminating against multiple classes. Notably, many proposals involve convolutional neural networks. Instead, classical machine learning approaches are still effective for binary classifications. Many proposals combine common spatial pattern, least absolute shrinkage and selection operator, and support vector machines. Regarding reported classification accuracies, performance above the upper quartile is in the 85%–100% range for the binary case and in the 83%–93% range for multi-class one. Associated uncertainties are up to 6% while repeatability for a predetermined dataset is up to 8%. Reproducibility assessment was instead prevented by lack of standardization in experiments. Significance. By relying on the analyzed studies, the reader is guided towards the development of a successful processing strategy as a crucial part of a BCI. Moreover, it is suggested that future studies should extend these approaches on data from more subjects and with custom experiments, even by investigating online operation. This would also enable the quantification of the results reproducibility.
Pareto-optimal trade-off for phenotypic switching of populations in a stochastic environment
Authors: Dinis L , Unterberger J , Lacoste D
Published: May 2022

Finding optimal survival strategies of living systems embedded in fluctuating environments generally involves a balance between phenotypic diversification and sensing. If we neglect sensing mechanisms, it is known that slow, resp. fast, environmental transitions favor a regime of heterogeneous, resp. homogeneous, phenotypic response. We focus here on the simplest non-trivial case, i.e. two randomly switching phenotypes subjected to two stochastically switching environments. The optimal asymptotic (long term) growth rate of this model was studied elsewhere; we further expand these results by discussing finite time growth rate fluctuations. An exact asymptotic expression for the variance, alongside with approximations valid in different regimes, are tested numerically in details. Our simulations of the dynamics suggest a close connection between this variance and the extinction probability, understood as risk for the population. Motivated by an earlier trade-off analysis between average capital growth rate and risk in Kelly’s gambling model, we study the trade-off between the average growth rate and the variance in the present model. Despite considerable differences between the two models, we find similar optimal trade-off curves (Pareto fronts), suggesting that our conclusions are robust, and broadly applicable in various fields ranging from biology/ecology to economics.
Spectral studies of inductively coupled plasma characteristics of low pressure discharges for two configurations of vacuum chambers
Authors: Shemakhin Yu A , Samsonova E S , Voznesenskiy E F , Zhelonkin Y O , Yu Shemakhin E , Fadeev S A , Terentev T N , Maksimov R A , Tyurin V A
Published: May 2022

In this work, we carried out comparative studies of the electron temperature in Inductive coupled radio frequency (ICRF) for two configurations of discharge chambers – cylindrical and flat, considered as prototypes of ICP technological modules of the installation in the argon pressure range from 10 to 50 Pa. The study used optical emission spectrometry of the plasma. As a result, the dependences of the electron temperature on pressure and power were obtained. It is shown that with increasing pressure, different dynamics of the electron temperature is observed for the cylindrical and plane geometry of the inductor.
Nanodiamonds from Fuel
Authors: Timerkaev B A , Shakirov R B , Zalyalieva A A , Gevorgyan R K , Shaikhattarov R R
Published: May 2022

In this paper, we present the results of the synthesis of nanodiamonds from carbon nanostructures and diamondoids in an arc discharge. The electrodes used in the experiments were a molybdenum cathode and a copper anode coated with carbon nanostructures such as carbon nanotubes and diamondoids. The formation of carbon nanostructures on the surface of a copper electrode was carried out in an electric arc sunk into fuel oil. At the next stage, these carbon nanostructures served as a source of atomic carbon and diamondoids from the surface of the arc discharge anode. The use of fuel oil as a feedstock for creating the electrode material probably led to the retention of diamondoids contained in fuel oil during two vaporizations. It was found that, in addition to carbon nanotubes, nanodiamonds also formed on the cathode surface.
The Effect of Jet Electric Discharge on the Strength Characteristics of the Surface
Authors: Akhatov M F , Kayumov R R , Mardanov R R , Loginova I M
Published: May 2022

In this paper, the results of measuring the density of the skin of metallic tissues using an installation for assessing the strength of damaged layers (sclerometer) MV-11m, a study of the treatment of tissues with an electrolytic discharge, are revealed.
Hysteresis Phenomena and the Effect of Reorientation in a Polymer-Liquid Crystal System Under the Influence of Laser Radiation and Uniaxial Deformation
Authors: Makhsudov B I , Fayzulloev I K , Egamov M K
Published: May 2022

The orientational structure in a polymer-liquid crystal thin film induced by uniaxial mechanical deformation has been studied. It is shown that the dependence of the deflection angle of the director of a nematic liquid crystal on the direction of the tensile force has a hysteresis region in which the orientation structure spontaneously changes from a state with positive torsion of the director to a state with negative torsion. It is established that the effect of modification of the hysteresis loop leads to an expansion of the hysteresis region and a decrease in the field at which orientation bistability appears.
Application of the Harrington function in substantiating the choice of the best equipment for plasma processing of materials
Authors: Tazmeev B K , Tsybulevsky V V , Tazmeeva R N , Tazmeev G K
Published: May 2022

The possibility of using the Harrington desirability function in choosing the most suitable equipment for plasma processing of materials is confirmed. The search for the optimal variant was carried out by calculating the maximum value of the generalized index of desirability. Four types of equipment for plasma cutting of metal are considered. A comparative analysis was carried out on the following indicators: the cost of equipment and technological cutting speeds for low carbon steel, stainless steel, and aluminum. An example of choosing the best equipment from an alternative series is considered. A system of four scales of partial evaluation indicators was used. Graphical and analytical evaluation methods are presented. The value of the generalized desirability index equal to 0.65 corresponds to the optimal variant of equipment for plasma cutting of metal.
Creation of plasma flow from a liquid electrolyte cathode with an arbitrary orientation in space
Authors: Tazmeev G K , Tazmeev K K , Tazmeev B K
Published: May 2022

The gas discharge between a metal electrode and a liquid electrolyte supplied through a porous refractory material has been experimentally studied. The studies were carried out in the current range of 5–15 A. Aqueous solutions of sodium chloride were used as a liquid electrolyte. The specific electrical conductivity of the solutions was in the range of 6–18 mS/cm. The conditions necessary for the formation of a plasma flow are revealed. Plasma flows oriented in different directions in space have been created. The energy and spectral properties of the gas discharge are investigated.
INVESTIGATION OF VOLT-FARAD CHARACTERISTICS OF THIN MULTIFERRROIC FILMS
Authors: Saidzoda Q B , Semenov A A , Safarov M M
Published: May 2022

In this work, the influence of the concentration of manganese ions in BST films on the capacitance-voltage characteristics (CV characteristics, I–V characteristics, tgδ) of the Cu-Cr/BST/α-Al2O3 and Cu-Cr/BST/GGG structures was studied. To measure the electrophysical characteristics, multiferroic thin-film the samples were made in the form of planar capacitors. Measurements of the electrical properties of the formed planar structures were carried out at a frequency of 1 MHz.
Features of a burning electric arc superimposed on gas discharge with liquid electrolyte cathode
Authors: Tazmeev K K , Tazmeev A K
Published: May 2022

The conditions for burning an electric arc in a discharge plasma with a solution cathode have been studied. Both discharges were connected to the same metal anode. The electric arc burned in the current range of 5–10 A. The discharge current with a solution cathode varied within 8-15 A. In the experiments, aqueous solutions of common salt were used. The specific electrical conductivity of the solutions was 10–15 mS/cm. Spectral investigations of arc plasma radiation and discharge with a solution cathode have been carried out. Calculations of the parameters of the electron gas in the plasma column have been performed.
Studies of a monatomic Lennard-Jones system at slow cooling by molecular dynamics simulations and regression analysis
Authors: Farkhutdinov A R
Published: May 2022

The procedure of radial distribution function calculation at low cooling rates without a substantial increase in the computational cost is proposed in this paper. Results of its application to monatomic Lennard-Jones system at cooling rates γ =4×10-4...2×10-2ε/kBτ, density ρ ≈0.75σ-3and temperature rangeT= 0.3. 1.0ε/kBτusing various regression models are given. It is shown that k-nearest neighbors regression yields the minimum deviation from the results of molecular dynamics simulations in comparison with other models.
A STABLE NUMERICAL ALGORITHM FOR INVESTIGATING THE PROPERTIES OF TWO-DIMENSIONAL LASER WAVEGUIDES IN MULTILAYER QUANTUM-DIMENSIONAL SEMICONDUCTOR HETEROSTRUCTURES
Authors: Sh. Juraev H. , Mamatkulova N.O. , Makhsudov B.I.
Published: May 2022

The transfer of heat through nanostructures differs significantly from the corresponding processes inside macroscopic bodies. Various research methods, both theoretical and experimental, are applied to such objects. This approach to nanostructures gives great advantages. The hyperbolic equations we have obtained describe the wave process of the thermal signal flow and the properties of heat transfer in nanostructures across a thin layer, in which the simplest task is to determine the thermal conductivity.
EFFECT OF TEMPERATURE, PRESSURE, AND FRACTION OF NANOPARTICLES ON CHANGES IN THE THERMAL CONDUCTIVITY OF COLLOID NANOFLUIDS
Authors: Tilloeva T R , Safarov M M , Zaripova M A
Published: May 2022

The paper presents the results of studies on the thermal diffusivity of colloidal nanofluids depending on the change in one of the state parameters (pressure). Studies were carried out both with a change in the pressure of the experiment, and with a change in the nanometric size of silver particles in a liquid. Based on the results obtained, the corresponding empirical equations were derived and a proper comparative analysis was performed by comparing the experimental and calculated data on thermal diffusivity. The suitability of the derived equations is evidenced by the satisfactory agreement between the obtained data and the calculated ones within 1.79% at α=0.95.
Density of Toluene-Based Nanofluids
Authors: Mirzoeva Q , Matlabi J , Safarov M M
Published: May 2022

The purpose of this work is to study the density of two-component titanium dioxide systems (nanosized particles of various fractions (30nm, -50nm and 70nm)) (up to 0.5%) + toluene in the temperature range (293) K at atmospheric pressure (0.101) Mpa.
Electrophysical parameters of AC plasma system
Authors: Oshenko I I , Smirnov S A
Published: May 2022

Experimental results related to main characteristics of an underwater discharge with a frequency of 50 Hz and various types of electrodes were reported. The data on 1) discharge geometry; 2) current-voltage characteristics; 3) gas temperature and reduced electric field strength; 4) plasma emission spectra were obtained. Based on these data, the plasma modeling provided the information on densities of plasma active species.
Universal Structural and Dynamic Features in Metals Near Their Melting Points
Authors: Khairullina R R , Khusnutdinov R M
Published: May 2022

The results of a comparative analysis of experimental data for the equilibrium properties and characteristics of liquid alkaline earth (magnesium, calcium, strontium), alkaline (lithium, sodium, potassium) and transition metal groups: elements of the subgroups of nickel (Ni, Pd, Pt) and copper (Cu, Ag, Au) near their melting points are presented. Reduced spatial r/rm
= rkm
/2π and time

t
/

t
m

=
t

k
m

/

m
β

scales, in which km
is the first peak position of the static structure factor S(k) and β = 1/kBT is the inverse temperature, are introduced as the basis for the law of corresponding states. Based on these scale transformations and x-ray diffraction analysis, it was found that the groups of liquid alkaline, alkaline earth, and transition metals are described by universal r- and k- dependencies. It has been established that the dispersion law of longitudinal polarization ωc
(k), given in accordance with these scale relations, for elements of groups of liquid alkaline, alkaline earth and transition metals has a single universal character. An analysis of the properties of three groups (alkaline, alkaline earth and transition) liquid metals using scale transformations shows that the law of the corresponding states is valid for these substances.
A model of the positive column of longitudinal glow discharge in planar channel with additional gas injection through the side walls
Authors: Galeev I G , Asadullin T Y , Valeeva D R
Published: May 2022

A model of positive glow discharge column in longitudinal flowing glow discharge with an additional distributed gas injection through the side walls of flat channel is proposed. The main flow is pumped through mesh electrodes located at the beginning and end of the discharge chamber. The solution of an integro-differential system of equations is obtained, expressions for the distribution of the electric field strength, the degree of gas ionization, and the gas temperature in the discharge region are given.
Local density dynamics in a supercritical Lennard-Jones fluid
Authors: Khabibullin R A
Published: May 2022

The collective particle dynamics of supercritical Lennard-Jones fluid is investigated on the basis of molecular dynamic modeling data. The intermediate scattering functions and dynamic structure factor spectra for the wavenumber range k ∈ [0.18; 3.26] σ−1 were calculated. The characteristics of dynamic structure factor spectra such as the thermal diffusivity and the sound velocity were estimated.
The development of statistical analysis methods for the study of correlations and statistical memory effects in the recorded data of physical experiments
Authors: Demin S A , Yunusov V A
Published: May 2022

In this paper, we discuss the prospects for the use of statistical analysis methods in the study of correlations and statistical memory effects in the experimental data of physical experiments. Developed methods under consideration: Memory Functions Formalism and Flicker-Noise Spectroscopy allow obtaining a large set of quantitative parameters and qualitative characteristics directly from temporal signals generated by complex physical systems. Additionally, for the study of collective phenomena and effects, one- and two-parameter cross-correlation functions are proposed, which allow studying cross-correlations between simultaneously recorded signals in spatially separated areas of the object under study. The introduced analytical relations and numerical algorithms can be applied to solve the problems of metrology of surface structures at the nano- and microlevels, to study collective phenomena in the plasma of astrophysical objects, the structure of molecules, and their complexes.
The study of statistical features of the evolution of complex physical systems using adaptive machine learning methods
Authors: Yunusov V A , Demin S A , Elenev A A
Published: May 2022

In this work, we discuss various machine learning methods and their implementation in the field of complex physical systems for the analysis of experimental data. These methods: classical machine learning, neural nets and deep learning allow greatly outperforming classical analysis methods by giving the algorithm the ability to “learn” and perform tasks adapting to the data provided and search. Neural nets and deep learning approaches are used to search for hidden patterns of the suggested input data that can’t be analyzed using common methods. This variety of methods can be applied to study collective phenomena in plasma and thermonuclear fusion on the basis of experimental data of physical experiments with a higher level of performance than classical approaches.
Pore formation in simple systems simulated by molecular dynamics
Authors: Khabibullin R A
Published: May 2022

Simulation of the pore formation process in a simple one-component system was performed. As the initial configuration of the system a crystal with FCC lattice was used. Pore formation and evolution were observed during isochoric melting of the crystal and subsequent fluid simulation.
Investigation of the structure of an aluminum nitride film for a Bragg reflector obtained by magnetron sputtering
Authors: Baranova L , Baysova B , Strunin V
Published: May 2022

The phase composition of the aluminum nitride film obtained through magnetron sputtering was determined with the help of X-ray phase analysis. The analysis revealed the AlN, Al and V phases deposited during the synthesis of the film. The structural parameters of the primitive unit cell of the AlN and Al phases were determined. The effect of texturing the resulting film was detected.
Control of The Distribution of The Internal Characteristics of The Discharge Using Supersonic Gas Pumping
Authors: Timerkaev B A , Petrova O A , Shamsutdinov R S , Sayfutdinov A I
Published: May 2022

Theoretical studies of the distribution of glow discharge parameters in a supersonic nitrogen gas flow between the central body of the nozzle and an annular electrode around the central body are carried out. Distributions of charged particle concentrations, potential, and electric field strength are obtained. The possibility of compaction or stretching of the cathode zones has been demonstrated. In the case of the organization of a supersonic gas flow near the central body-the anode, all the near-electrode zones are pressed against the anode. In this case, the cathode is located in the area of reduced pressures. Such a way of organizing the discharge can find application in the processes of applying functional coatings.
Production of Hydrogen From Heavy Hydrocarbons
Authors: Timerkaev B A , Ganieva G R , Shakirov B R , Zalyalieva A A , Shamsutdinov R S
Published: May 2022

The mechanism of the effect of an arc discharge on heavy hydrocarbon raw materials is studied in the work. The mechanism of formation of charged particles in micro-discharges with recessed electrodes is shock ionization. As a result of the interaction of hydrocarbon raw materials with an arc discharge, long hydrocarbon molecules are broken down, light hydrocarbons such as ethylene, hydrogen, and methane are formed. In the case of the organization of a micro-arc discharge, a gentle thermal regime also provides a gentle splitting of long hydrocarbon molecules, and in this case gasoline fractions of oil are formed in greater quantities compared to the case of exposure to raw materials by a conventional arc discharge.
Hydrophilization of the surface of a natural hydrophobic material by non-equilibrium low-temperature plazma
Authors: Rakhmatullina G R , Tikhonova V P , Nizamova D K , Akhverdiyev R F , Bigeyeva K F
Published: May 2022

We considered the effect of non-equilibrium low-temperature plasma for hydrophilization the surface of fish skins. Fish skin is a hydrophobic material in its nature. The relevance of this issue is justified by fact that the dressing of animal skin is a series of consecutive liquid processes. Natural structure of fish skins promotes the poor diffusion of working solutions, so it hinders a chemical modification of materials. The plasma processing of fish skin provides the partition of supramolecular structure of collagen (basic protein of dermis) due to disruption of weak intermolecular bonds. This leads to better diffusion of chemical materials and as a result, liquid processes intensify and time production cycle reduces.
Application of plasma methods for the synthesis of nanostructures
Authors: Masyanov A A
Published: May 2022

There are many plasma methods for the synthesis of nanostructures, for example, the plasma-chemical vapor deposition method, the cathode-arc deposition method, the plasma jet method, the ion sputtering method, etc. Each of the listed methods can be organized in various ways, and each method is suitable for creating certain nanostructure.
First-Principle Molecular Dynamics Study of Methane Hydrate
Authors: Yunusov M B , Khusnutdinov R M
Published: May 2022

Currently, much attention of the scientific community and the gas industry is focused on the structural, physical and thermodynamic properties of gas hydrates. This interest is explained by the fact that there is a prospect of using natural gas hydrates as a new fuel source. This article presents the results obtained during the first-principle molecular dynamic study of the thermal and electronic properties of hydrates. For hydrates of methane with cubic sI and hexagonal sH configurations, the average heat capacity Cv
was computed. The densities of electronic states are studied for filled and unfilled configurations of sI and sH hydrates. The spectra of electron energy were calculated for sI hydrate, which has unfilled molecular cages. Also, for methane and ethane hydrates, the binding energies between the framework and the gas molecule are calculated.
Experimental and computational study of arc discharges in powerful alternate arc heater
Authors: Mironov V V , Kozaev A S , Negodyaev A S
Published: May 2022

The paper deals with the results of computational and experimental research on the formation process of electric arc discharges in a three-phase Zvezda-type alternating current arc heater. A flow modelling in the arc heater, as well as an experiment on providing a visual control for the location and the shape of arc discharges were conducted. A device of a visual control system is presented. The analysis of the results obtained from experimental research is carried out.
A new approach to estimating kinetic rate factors of phase transformations
Authors: Yarullin Dinar T.
Published: May 2022

An original approach is proposed to estimate of the main kinetic factors that determine the rate of phase transformations in condensed matter. These factors define the frequency of atom transitions from different phases during phase transformation induced by undercooling, high pressures or mechanical impact. On the example of crystallization of a model amorphous system, it is shown that this approach gives a correct estimation of the crystal growth and crystal decay rates both at the initial stage of the phase transition and at the stage of coalescence of crystalline structures.
Investigation of a high-frequency magnetron sputtering system operation modes during copper thin films deposition
Authors: Tumanov N A , Kirillov D V , Vorob’ev E V
Published: May 2022

The results of studying the radio frequency (RF) magnetron sputtering (MS) operation parameters during copper sputtering are presented. A comparison of the growth rate dependence on power during the operation of MS is made in RF and DC modes. The pressure dependences of the RFMS growth rate and bias target voltage are obtained. The prospect of using RFMS for deposition of smooth coatings is shown.
Confidence of nano-measurements of Hf-Ti-N multilayer PVD condensates from the plasma phase
Authors: Mironov M M , Grebenshchikova M M
Published: May 2022

The microhardness and thickness of PVD coating layers made of titanium and hafnium nitrides were measured experimentally. The standards of TC 441 were analyzed. The sequence (protocol) of the analysis of nano-measurements and obtaining reliable measurement results was given. To obtain a quantitative value of the reliability of measurements for superhard nanocoats is proposed to use for educational purposes the calculation of the confidence interval using the Student criterion.
Three-color pyrometry study of radiation and gas dynamic processes in a heterogeneous plasma-vortex ring
Authors: Volodin L Y
Published: May 2022

The paper presents the results of a study of a heterogeneous plasma vortex ring using the three-color image pyrometry technique. The vortex ring is formed during deceleration of a supersonic pulsed aluminum plasma jet in atmospheric air. A technique for calibrating a digital camera and a post-processing process for images are proposed that makes it possible to visualize the internal structure of the vortex. As a result of the study, the effect of vortex separation of condensed and gas flow components was experimentally demonstrated.
Electric discharge generator of long-lived plasma formations in atmospheric pressure air
Authors: Volodin L Y , Kamrukov A S
Published: May 2022

The paper presents the results of a study of the developed pulsed plasma generator based on the cylindrical foil electric explosion. The generator is used to form large-scale toroidal plasma vortices in atmospheric air. The influence of the specific stored energy on the phase composition of the plasma flow and the lifetime of plasmoids using a high-speed camera was studied. It was found that large condensed particles in the flow do not participate in the vortex motion and cause the destruction of plasma vortices. The formation conditions of stable plasma vortices were determined.
Finite-difference scheme and algorithm for solving a two-dimensional system of Maxwell’s equations for inductively coupled plasma
Authors: Gerasimov A V , Kirpichnikov A P , Gaynullin R N , Lapteva Y D , Pham T M
Published: May 2022

The paper presents a numerical scheme for solving a two-dimensional system of Maxwell equations for a cylindrical coordinate system.
The 3rd International Conference on Geoscience and Earth Resources Engineering: Geosciences and Earth Resources Engineering for Sustainable Future (Preface)
Authors: Sahara David P. , Hidayat Taufiq , Aslam Billal Maydika , Zulfakriza  , Wattimena Ridho K. , Syafrizal  , Alawiyah Susanti
Published: May 2022

The issue of IOP Conference Series: Earth and Environmental Science contains the outstanding papers presented at International Conference on Geoscience and Earth Resources Engineering (ICGERE) 2021. Due to Covid-19 Pandemic, the 3rd ICGERE 2021 Conference was held online on 8 – 9 December 2021.

List of Committees are available in this pdf.
Manufacture Hollow Glass Microsphere (HGS) in University Laboratory Scale (Phase 1)
Authors: Marbun B T H , Pande B , Sinaga S Z , Purbantanu B A
Published: May 2022

Hollow Glass Microsphere (HGS) can be used as an additive of drilling fluid to decrease the density and hydrostatic pressure without changing the chemistry characteristic to make underbalanced drilling condition. HGS is relatively easier to be mixed with the fluid without complicated equipment, can prevent formation damage, and can improve oil and gas production. There are various HGS commercial products that have been developed in the industry for various purposes with a density range 0.125-1.1 gr/cm3, grain size range 2-120 μm, and compressive strength up to 200 MPa. HGS has been successfully used in underbalanced drilling operation in several oil and gas fields in Indonesia. HGS costs less than UBD and the application shows good results with the improvement of oil and gas production. However, the cost of commercial HGS products in the market is very expensive. Petroleum Engineering Study Program Institut Teknologi Bandung (ITB) performed the HGS research in three phases. The first phase reported in this paper was to manufacture HGS in the university laboratory scale. HGS was manufactured based on various chemical compositions and temperature and time variation of the burning process. Scanning Electron Microscope (SEM), Energy Dispersive Spectrometry (EDS), and X-Ray Diffraction (XRD) analysis were performed to identify and characterize the raw chemical material and manufactured HGS. HGS was successfully manufactured with the following characteristics: low density (<0.8 gr/cm3) and low grain size (20-40 μm). These characteristics show that HGS can compete with commercial industry HGS products that have been successfully used in the underbalanced drilling operation. The second phase is to scale-up manufacture HGS from university laboratory scale to industrial scale. The third phase is to test the manufactured HGS with drilling fluid according to the American Petroleum Institute (API) Spec. 13A and API Spec. 13B-1.
3D gravity data inversion modeling for subsurface identification of Gondang area, Bojonegoro regency
Authors: Mariyanto Mariyanto , Darmawan Reyhan Dzaky , Utama Widya
Published: May 2022

Gondang area had experienced an earthquake of a 4.2 magnitude in the mid-2015, showing that tectonics in the area are active. Also, the Gondang area has a mountain categorized as one of the eleven earth thermal prospects in East Java, i.e., Pandan Mountain. It is exciting to study the subsurface structures of the Gondang area. To date, precedent studies only present geological reviews of the surface. This study presents information on subsurface structure conditions based on gravity. The technique used was 3D inversion modeling with Single Value Decomposition (SVD) inversion. The study ’ s primary data were gravity data from 61 points with a study area of 6.9 km x 5.5 km from 3-10 September 2019. Secondary data utilized were Bojonegoro geological map and local geological studies. From 3D modeling results, slicing was conducted for five cross-sections based on density contrast. Then, the subsurface 2D cross-section results were interpreted for each section. Subsurface model results illustrated density distributions in south, northeast, and northwest areas with high densities ranging from 2.8 g/cc to 3.0 g/cc in >500 m depths. Meanwhile, the north, southwest, and southeast areas had low densities ranging from 1.70 g/cc to 2.0 g/cc in >500 m depths. Furthermore, it indicates the continuity of andesite intrusion from the south to the study site in >500 m depths.
Groundwater play in extensional regime: a case study in Cibunar Region, Garut, Indonesia
Authors: Hanif M , Parnadi W W
Published: May 2022

The intermountain Cibunar area of the Garut basin periodically suffered from a drought and thus became a devastating hazard. Its fault structure as an impact of the extensional regime might affect the groundwater play as a transport or barrier system. The tectonic setting and its disruption of volcanic lithologies by faults make the area's hydrogeology very complex. The conducted electrical resistivity tomography coupled with gravity and magneto-telluric studies revealed the aquifer play on the zone is affected by the extensional regime. Tectonically, the drought Cibunar district is close to the top of the horst structure where the uplifted segments might contribute to the limited low resistivity aquifer zone and triggered the flow to the graben zone. The low and high resistivity on the region was related to an unconfined aquifer and unsaturated zone, while the medium zone remains unclear.
Electrical resistivity survey for groundwater investigation in Padalarang, West Java
Authors: Phanjaya H , Parnadi W W , Santoso D
Published: May 2022

An electrical resistivity survey has been carried out in Padalarang, West Java, to investigate groundwater potential to solve the lack of clean water. The survey consists of three vertical electrical sounding (VES) and four electrical resistivity tomography (ERT) profiles in the study area. The data was processed using inversion method. Wells in the area is available to validate resistivity data. The result of VES shows a low resistivity value (2.82 - 11.72 Ωm) at its fourth layer, which we expected to be a zone with high water content. ERTs result also revealed a low resistivity value (<10.1 Ωm), approximately more than 60 m depth at ERT 3 and 4. We expect this low resistivity zone to have a groundwater potential. A low resistivity zone in the central part of the study area may yield a high groundwater potential. Our result could serve as a guide to engineers for planning on sitting boreholes either for domestic, agricultural, or industrial use.
Scaling and corrosion formation mechanism in geothermal piping system based on Pourbaix-Lindal diagram-Ryznar index and fluid velocity profile
Authors: Sutarno  , Syuryana E. P. , Saefudin D. B.
Published: May 2022

Geothermal fluid flow contains scale and corrosion species whose levels differ from each location of geothermal sources. The velocity of scale formation and corrosion mechanism due to specific parameters in case of total key species, flow rate, pressure and temperature of the geothermal fluid based on the Pourbaix-Lindal diagram -Ryznar index. The reduction in pipe diameter due to the scaling formation on the internal surface of the pipe correlates with the flow rate of geothermal fluid into the turbine, which drives the generator to produce electrical energy. This paper describes the mechanism of scale formation and the potential for corrosion on the internal surface of the piping through the momentum transfer approach of geothermal fluids to the turbine. Through this mechanism, curative and preventive measures can be taken to prevent premature degradation of the function and economic life of the geothermal piping system. The mathematical simulation results of fluid displacement momentum, the velocity of geothermal fluid flow, show that the velocity profile at the fluid-internal surface contact of the pipe is zero, which means that the species is at rest on the internal surface of the pipe. Thus, for scale species it will form a scale, while for corrosive species there will be a corrosion process on the internal surface of the pipe.