bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of the Kohonen neural network for monitoring tissue oxygen supply under hypoxic conditions
Authors: Mazing M S , Zaitceva A Y , Davydov R V
Published: December 2021

The article presents the results of application of the Kohonen artificial neural network (KANN) in assessing the oxygen status of human tissues, as well as for studying the adaptive-compensatory response of the body to functional load. In the experiment, the registered digital oxygen images of the tissue of 31 subjects were distributed into three classes using the KANN. Each group is characterised by different resistance of the organism to hypoxia. The research results have shown the effectiveness of using an artificial neural network structure and the possibility of its implementation for recognition of the functional state of a person under conditions of metabolic hypoxia; it seems relevant and has theoretical and practical significance in the framework of ecological physiology.
Thermostability of lysozyme amyloid fibrils
Authors: Melnikova N M , Sulatsky M I , Diordienko Yu D , Sulatskaya A I
Published: December 2021

Ordered protein aggregates, amyloid fibrils, are a marker of many serious diseases, such as Alzheimer’s, Parkinson’s, prion diseases, etc. At present, special attention is paid to the study of external influences that can affect the structure and stability of mature amyloid fibrils, which may be in demand in the development of approaches to the therapy of amyloidosis, as well as in the creation of new high-strength materials on the basis of these protein aggregates. An external factor, the influence of which on fibrils was studied in this work, was temperature denaturation. It was shown that heating lysozyme amyloid fibrils to 60 °C does not lead to their degradation, but leads only to a reversible increase in the intramolecular mobility of amyloid-forming proteins, but does not change their morphology. At the same time, boiling of lysozyme amyloids leads to their irreversible degradation, which occurs at least 5 days after exposure: fibrils that form larger clusters change their secondary structure, and fibrils with a lesser degree of clustering are divided into separate fibers. Obtained data about the factors that change the stability and structure of amyloids can be applied in biotechnology for creating new high-strength nanomaterials on their basis.
Computational modeling of schedule-specific chemotherapy outcomes in mouse tumor model
Authors: Terterov I N , Chubenko V A , Knyazev N A , Klimenko V V , Bogdanov A A , Moiseyenko V M , Bogdanov A A
Published: December 2021

Despite the rapid development of new innovative strategies in cancer treatment like immunotherapy, chemotherapy still remains a common choice in many cases. Standard protocols of chemotherapeutic administration rely on a maximal tolerated dose paradigm, however there is growing evidence that this approach is not always optimal. Alternative scheduling, like metronomic - low dose continuous drug administration - were recently proved their efficacy. The space of available variants of drug administration protocols is prohibitively large to be explored empirically, and there is an urgent need of predictive mathematical models for rational chemotherapeutic scheduling design. In this work we tested the ability of the minimal pharmacokinetic-pharmacodynamics model to describe schedule-specific tumor volume time evolution in different mouse tumor models.
Method development to secure the stability of the parameters of pulsed and continuous radiation in laser systems with semiconductor pumping
Authors: Abdurakhmanova S R , Bukharov G D , Gheisser Z S , Davydov V V , Rud V Yu
Published: December 2021

The necessity of increasing the stability of the parameters of pulsed and cw laser radiation when operating at peak powers is substantiated. Particular attention is paid to the parameters of pulsed laser radiation in systems with semiconductor pumping. The main requirement in this case is the repeatability of the parameters of the output pulses with high accuracy. This condition is ensured by the stability of the diode supply drivers, especially at peak powers, which are required for scientific research. It was found that even a short-term excess (about 1 ms) of the upper range of the permissible current leads to damage to the laser diode, which instantly degrades the parameters of laser radiation. The developed technique can significantly reduce the likelihood of these phenomena and increase the reliability of the laser.
Mn4+ concentration effect on spectral properties of lithium-germanate glass-ceramics
Authors: Babkina A N , Kovova M S , Kulpina E V , Pavliuk A S , Zyryanova K S , Monogarova A A , Bukhvostov A I , Ignatiev A I , Nuryev R K
Published: December 2021

A series of lithium-germanate glasses with different manganese concentration is synthesized. Li2Ge7O15 nanocrystals nucleate in the glass matrix via standard volume crystallization technique thus obtaining lithium-germanate glass-ceramics. The glass-ceramics possess intense emission near 660-670 nm under two-band excitation at 330 and 450 nm. The luminescence lifetime is 550 μs for 0.05 mol.% MnO2-doped glass-ceramics. The glass-ceramics obtained can be used as a source of deep-red radiation.
Synthesis and studying properties of the GNPs@FexOy structure
Authors: Bespalova P G , Vorobyev A A , Speshilova A B , Studzinsky V M , Patirimova E A , Karasev P A , Mishin M V
Published: December 2021

An article presents a study of the regularities of the formation of gold up to 8 nm thick, deposited by vacuum thermal deposition on silicon wafers with a natural oxide, its annealing and subsequent deposition of iron oxide by chemical vapor deposition. The stages were accompanied by SEM analysis of the sample surface, as well as fixation of the optical and FTIR spectra, I–V characteristics of the obtained structures.
Coherent tunable diffractional pulse shaping and generation of the 0π-pulse in Rb vapor
Authors: Bagayev S N , Averchenko V A , Chekhonin I A , Chekhonin M A , Balmaev I M , Mekhov I B
Published: December 2021

We have experimentally studied for the first time a new operation principle of the coherent diffractional pulse shaper (Rabi shaper). In the experiment, we observed an effect of tunable pulse shaping of nanosecond semiconductor laser pulse during the resonant pumping of the D2 line (780.24 nm) of 87Rb vapor in the range of self-diffraction angles φ = ± 4°. We observed the synthesis of nanosecond 0π-pulses at the small length of the nonlinear interaction 0.1…1 mm. We propose to use the Rabi shaper as an energy efficient tunable shaper of classical and single-photon wave packets. We analyze a possibility of the Rabi shaper operation in quantum systems with feedback.
Condition monitoring of current media using a differential refractometer
Authors: Svyatkina V I , Davydov V V , Rud V Yu
Published: December 2021

A new design of a differential flow refractometer has been developed to monitor the condition of flowing media in a pipeline. A new method of refractive index measurement has been implemented, taking into account the specifics of flowing and closed cuvette arrangement, as well as the angles of incidence of laser radiation on their walls. The effect of changes in the optical density in the flowing liquid on the refractive index measurement result is determined. The results of experimental investigations of different media are presented.
Characterization of In(Ga,Al)As/GaAs metamorphic heterostructures for mid-IR emitters by FTIR photoreflectance spectroscopy
Authors: Firsov D D , Chernov M Yu , Solov’ev V A , Komkov O S
Published: December 2021

Infrared photoreflectance (PR) spectra of In(Ga,Al)As/GaAs metamorphic heterostructures have been obtained using a novel photomodulation FTIR spectroscopy technique. An analysis of the PR spectra features allowed us to estimate the critical point energies corresponding to the direct interband transitions in various regions of the In(Ga,Al)As heterostructures, and distinguish the PR signals originating from Fabry-Perot interference. Observation of Franz-Keldysh oscillations originating from the InAlAs virtual substrate and an InGaAs waveguide layer has enabled determination of the built-in electric field intensities within the heterostructures. The obtained results open up possibilities for contactless control of free carrier concentration in In(Ga,Al)As/GaAs metamorphic heterostructures developed for growth of emitters of mid-IR spectral range.
On the need to control the state of the upper edge of the prism in a flow-through refractometer for measurements with an error less than 10−4
Authors: Isakov F A , Davydov V V , Rud V Yu
Published: December 2021

The article substantiates the need to use a flow-through refractometer to control the state of a flowing liquid during scientific research, when automating a technological process, etc. The main negative factors that affect an increase in the measurement error of the refractive index n of a flowing liquid are determined. It was found that one of these factors is the formation of a thin film (plaque) on the upper face of the prism, which is in contact with the medium under study. The study of the influence of this film on the measurement error has been carried out. A method has been developed to eliminate plaque from the upper face of the prism during the operation of the refractometer. The results of experimental studies are presented.
Neural networks application to determine the types and magnitude of aberrations from the pattern of the point spread function out of the focal plane
Authors: Khorin P A , Dzyuba A P , Serafimovich P G , Khonina S N
Published: December 2021

Recognition of the types of aberrations corresponding to individual Zernike functions were carried out from the pattern of the intensity of the point spread function (PSF) outside the focal plane using convolutional neural networks. The PSF intensity patterns outside the focal plane are more informative in comparison with the focal plane even for small values/magnitudes of aberrations. The mean prediction errors of the neural network for each type of aberration were obtained for a set of 8 Zernike functions from a dataset of 2 thousand pictures of out-of-focal PSFs. As a result of training, for the considered types of aberrations, the obtained averaged absolute errors do not exceed 0.0053, which corresponds to an almost threefold decrease in the error in comparison with the same result for focal PSFs.
Traffic interception in fiber optical video-systems
Authors: Krivenko Yu E , Andreeva E I
Published: December 2021

In fiber-optic video systems, as well as in optical communication systems, standard single mode optical fibers (SSMF, standard G.652) are usually used. One of the advantages of these fibers is the ability to use CWDM in a wide spectrum. At the same time, more optimal near the wave-length of 1550 nm are provided by non-zero dispersion fiber (NZDSF, standard G.655) fibers. However, as studies have shown, these optical fibers have an increased sensitivity to bending. This fact can be used to traffic interception. It is shown that fiber-optics systems with SSMF have more protection from traffic interception than systems with NZDSF. To transmit a high-confidentiality video signal, special techniques, such as frequency modulation, can be used, or additional noise signals can be added.
Peculiarities of ion-exchange in poled glasses
Authors: Lubyankina E A , Raskhodchikov D V , Babich E S , Kaasik V P , Lipovskii A A
Published: December 2021

We demonstrate for the first time that the results of ion exchange processing of thermally poled soda-lime glass essentially depend on the poling conditions. In particular, the processing of vacuum-poled soda-lime glass in silver-sodium nitrate melt results in the diffusion and reduction of silver ions followed by clustering silver nanoparticles in the subsurface layer of the glass after either ion-exchange or additional heat treatment of the ion-exchanged samples. Poling in air atmosphere with deposited gold film anode prevents silver ions penetration in the glass, but electric field stimulated diffusion of gold in this configuration leads to the formation of gold nanoparticles in the glass after heat treatment. It is also shown that corona poling of the glass in air atmosphere does not completely block silver penetration.
Organic phosphor based fiber-optic sensor for detection of UV radiation
Authors: Matrosova A S , Ananyev V A , Pchelkin G A , Shurupov D N , Evstropiev S K , Volynkin V M , Demidov V V , Nikonorov N V
Published: December 2021

The paper presents a simple and low-cost fiber-optic sensor for detection of UV radiation. A sensor construction consists of a silica capillary with a photoactive composition based on an organic phosphor, organic solvent and epoxyacrylate inside and a multimode optical fiber in contact with each other. By adjusting the proportion of components in a photoactive composition, it is possible to obtain a pronounced optical signal at wavelength near 440 nm which is the luminescence emission wavelength of the chosen organic phosphor. The potential of using the construction as a UV sensor is confirmed by the linear dependence of the optical signal amplitude at the fiber output on the optical power supplied to the fiber input.
Magneto-Optical Spectra of Magnetic Photonic Crystal with Composite (SiO2-Au) Layer
Authors: Mikhailova T V , Osmanov S V , Boyko V O
Published: December 2021

The resonant enhancement of magneto-optical effects due to structure modes arising at the boundary of magnetic photonic crystal [TiO2 / SiO2]
m
/ iron garnet / SiO2 / (SiO2-Au), in which the upper layer (SiO2-Au) is a composite layer of SiO2 with metallic Au nanoscale inclusions, and iron garnet is a bi-layer of composition Bi1.0Lu0.5Gd1.5Fe4.2Al0.8O12 / Bi2.3Dy0.7Fe4.2Ga0.8O12, has been considered by modelling of 4×4 transfer matrix method.
Raman spectroscopy and optical microscopy of medical infusion solutions for parenteral nutrition
Authors: Pimakhina E V , Pimakhin A A , Vishnykov N V , Tolkach N M , Arsentiev S B
Published: December 2021

Usage of Raman spectroscopy, optical microscopy, and retaining track membranes to find 20% SMOFlipid microparticles with a diameter of 5 to 10 μm and to prevent complications that arise during parenteral nutrition.
Numerical simulation of optical coupling between a microring resonator and a directly connected straight waveguide
Authors: Pirogov V V , Scherbak S A , Lipovskii A A , Kryzhanovskaya N V , Zhukov A E
Published: December 2021

We studied numerically optical coupling of whispering gallery modes of a microring resonator with modes of a radially directed straight waveguide connected to the microring. Optical outcoupling from the resonator through the waveguide was calculated for different widths of the latter. The output was maximized under conditions when the width fits an odd integer number of half-wavelengths of light inside the microring.
Investigation of the dielectric fatigue on the example of lead titanate films PbTiO3
Authors: Fimin A V , Pecherskaya E A , Timokhina O A , Aleksandrov V S , Volik A V , Shepeleva A E
Published: December 2021

The phenomenon of dielectric fatigue of active dielectrics, which consists in a decrease in the residual polarization depending on the number of switching cycles, is researched. A model of the dependence of the residual polarization of ferroelectric materials on the number of switching cycles is proposed. The model is based on piecewise - linear approximation of the results of measurements of the hysteresis loops of thin films PbTiO3
at a temperature T = 470 (°C), the electric field strength E = 100 (kV/cm). The developed model was used in the development of a technique for studying dielectric fatigue, depending on different modes of material switching.
Structure and characteristics of a thin-layer "aluminum - carbon nanotubes" sandwich structure
Authors: Fomin A , Koshuro V , Fomina M , Aman A , Palis S
Published: December 2021

The study describes a way to produce thin-layer sandwich structures containing layers of aluminum foil and an interlayer filler of carbon nanotubes (CNTs). To obtain a homogeneous structure of the composite, induction heat treatment was used combined with a device providing primary compression of the assembly. To determine the functional characteristics of sandwich structures, the homogeneity of their microstructure and surface conductivity were studied. It was found that the use of CNTs allowed increasing the surface conductivity by a factor of 8.3–9.5 compared to the sandwich structure without filler.
Single-step alkaline etching of deep silicon cavities for chip-scale atomic clock technology
Authors: Komarevtsev I , Akulshin Y , Kazakin A
Published: December 2021

This paper presents the results of experiments on the development of the technology of MEMS alkali vapor cells for a miniature quantum frequency standard. The classical design of a two-chamber silicon cell containing an optical chamber, shallow filtration channels and a technical container for a solid-state alkali source was implemented in a single-step process of wet anisotropic silicon etching. To prevent the destruction of the filtration channels during etching of the through silicon cavities, the shapes of the compensating structures at the convex corners of the silicon nitride mask were calculated and the composition of the silicon etchant was experimentally found. The experiments results were used in the manufacture of chip-scale atomic clock cells containing vapors of 87Rb or 133Cs isotopes in the neon atmosphere.
Optimization of deep silicon etching process for microstructures fabrication
Authors: Kuzmenko V , Miakonkikh A , Rudenko K
Published: December 2021

The paper presents the study of cyclic process of deep anisotropic silicon etching, called Oxi-Etch, in which the steps of etching and oxidation alternate, allowing deep etching of silicon with an anisotropic profile. This process forms typical for cyclic etching process sidewall profile called scalloping. Opportunities for modification and optimization of the process for specific application were investigated. The effects of optimization of the bias voltage and the duration of the etching step on the parameters of the resulting structures, such as the etching depth, wall roughness, and the accuracy of transferring the lithographic size, are considered. Balance between etch rate and scalloping was established.
Separation of III-N partially-coalesced nanowire arrays from Si substrate
Authors: Lendyashova V V , Kotlyar K P , Gridchin V O , Reznik R R , Lihachev A I , Shubina K Yu , Berezovskaya T N , Nikitina E V , Soshnikov I P , Cirlin G E
Published: December 2021

In modern optoelectronics, arrays or single nanowires (NWs) of III-N materials, in particular InGaN, separated from the original substrates are used to fabricate light-emitting diodes or single photon sources. This work describes a technology of separation super-dense arrays or arrays of partially-coalesced InGaN nanowires and single nanowires from a Si substrate by chemical etching in HF:HNO3 solution, which allows preserving the optical properties of the structure for further use.
Influence of active structure parameters on resonant frequency of acoustic transducer membranes
Authors: Malokhatko S V , Gusev E Yu , Ageev O A
Published: December 2021

The paper presents the results of calculations of the resonant frequency of a multilayer square membrane for ultrasonic microelectromechanical sensors. Various combinations of active layer materials and metal electrodes were taken into account. The dependences of the resonant frequency on the side length of membrane, as well as on the thickness of active piezoelectric layer and metal electrode for SiO2/Ti/ZnO, SiO2/Al/ZnO, SiO2/Ti/PZT and SiO2/Al/PZT structures were ob-tained. According to the calculations, the values of the resonant frequencies are in the ranges of 46.1–498.3 kHz for SiO2/Ti/ZnO; 45.4–477.3 kHz for SiO2/Al/ZnO; 39.4–411.4 kHz for SiO2/Ti/PZT; 38.1–381 kHz for SiO2/Al/PZT. It is shown that the resonant frequency can be increased due to changes in the geometric parameters of the membrane; and the material and dimensions of the piezoelectric layer have the greatest influence. The results of analytical and numerical simulations for particular case of SiO2(1μm)/Ti(1μm)/ZnO(2μm)/Ti(1μm) membrane with a side length of 600 μm are also compared. The obtained results could be used to optimize the design and process technology of microelectrome-chanical ultrasonic sensors.
Modeling of the interaction of porphyrin molecules in a nonpolar solvent
Authors: Mironyuk V N , Al-Hassani A J R , Al-Alwani A J K , Begletsova N N , Gavrikov M V , Kolesnikova A S , Pozharov M V , Glukhovskoy E G
Published: December 2021

The article presents the data of a theoretical molecular dynamics study of the interaction between a pair of porphyrin molecules, i.e. symmetrically substituted 5,10,15,20-tetra (4-n-methyloxyphenyl) porphyrin (P) and asymmetrically substituted 5-(4 hydroxyphenyl)-10,15,20-tris (4-n-methyloxyphenyl) porphyrin (P-OH). We studied three systems, each of which consisted of a pair of porphyrin molecules (P || P, P-OH ↑↑ P-OH and P-OH ↑↓ P-OH) and chloroform molecules as a non-polar solvent. The effect of substitution, different orientations of asymmetrically substituted molecules and temperature on the geometry and energy of the system was investigated. It was shown that all three systems show signs of a true solution with chloroform as a solvent; the distance between asymmetrically substituted P-OH molecules was less than in the case of two P molecules. This may serve as an indirect evidence that the molecules are not prone to aggregation in the presence of chloroform.
Spin-dependent transport through helical Aharonov-Bohm interferometer
Authors: Niyazov R A , Aristov D N , Kachorovskii V Yu
Published: December 2021

We discuss spin-dependent transport via tunneling Aharonov-Bohm interferometer formed by helical edge states tunnel-coupled to helical leads. We focus on the experimentally relevant high-temperature case as compared to the level spacing and obtain the full 4×4 matrix of transmission coefficients in the presence of magnetic impurities. We show that spin conserving and spin-flip transmission coefficients of the setup can be effectively tuned by the magnetic flux. These features are attractive due to possible applications for spintronics, magnetic field detection, and quantum computing.
Improving the mechanical properties of tool steel by induction chemical-thermal treatment
Authors: Palkanov P , Koshuro V , Fomin A
Published: December 2021

The study results of the structure and microhardness of the surface layer of high-speed tool steel after induction chemical-thermal treatment in a gaseous nitrogen-containing medium at a temperature of 900–1100 °C were presented. Due to the strengthening treatment of products a gradient diffusion nitride layer with a thickness of about 200 μm and a surface microhardness of 1950±70 HV1 98 was formed.
In situ Investigation of Individual Filament Growth in Conducting Bridge Memristor by Contact Scanning Capacitance Microscopy
Authors: Ryabova M A , Antonov D A , Kruglov A V , Antonov I N , Filatov D O , Gorshkov O N
Published: December 2021

We report on the application of Contact Scanning Capacitance Microscopy (CSCM) to trace the growth of an individual Ni filament in a ZrO2(Y) film on a Ni sublayer (together with a conductive Atomic Force Microscope probe composing a nanometer-sized virtual memristor). An increasing of the filament length in the course of electro-forming results in an increasing of the capacitance between the probe and the sample, which can be detected by CSCM technique. This way, the filament growth can be monitored in real time in situ.
Probing electric properties of GaP nanowires with Kelvin probe force microscopy
Authors: Sharov V A , Alekseev P A , Fedorov V V , Mukhin I S
Published: December 2021

Surface electronic properties of GaP nanowires were investigated using scanning probe force microscopy. I-V curves of individual free-standing NWs with different doping types were obtained. Surface Fermi level positions in the nanowires of different crystal phases and doping types were extracted using phase-modulated Kelvin probe force microscopy. The results indicate on weak Fermi level pinning in GaP nanowires. The difference between wurtzite and zinc blende GaP work function is observed.
Study of the hardness distribution after induction heat treatment of titanium over the surface and the cross-section
Authors: Shchelkunov A , Egorov I , Fomin A
Published: December 2021

In this work, the mechanical properties (microhardness) of a titanium disk after induction heat treatment (IHT) were studied. The influence of the processing parameters (inductor current and temperature) on the distribution of microhardness over the cross-section of the experimental samples was established.
Study of ripple formation on Si surface under Ga ion beam bombardment
Authors: Smirnova M A , Ivanov A S , Bachurin V I , Churilov A B
Published: December 2021

The process of microrelief formation on Si (100) surface under 30 keV Ga+ ion beam bombardment with doses 2⋅1017 - 4⋅1018 ion/cm2 at incident angles θ = 0 - 50° was studied. It was found that wave-like structures form on the surface at θ = 25° - 35° and doses 6⋅1017 - 2⋅1018 ion/cm2. The nice ripple formed at θ = 30±2° incident angles and irradiation dose 1018 ion/cm2.
Normal-state transport in superconducting NbN films on r-cut sapphire
Authors: Soldatenkova M D , Triznova A D , Baeva E M , Zolotov P I , Lomakin A I , Kardakova A I , Goltsman G N
Published: December 2021

High-quality thin NbN films are very crucial for realizing quantum devices. Here, we investigated electrical transport and noise properties of a series of thin NbN films of various thicknesses grown on r-cut sapphire substrate using a DC magnetron sputtering technique. The films exhibit non-uniform thickness dependences for superconducting transition temperature (Te
) and normal-state resistivity. Morphological characterization of NbN samples of various thicknesses reveals uniform structure in thin films and granular structure in thick films. By measuring transport and noise properties in a normal state, we observe that the granular structure of NbN films does not have a strong effect on resistivity and does not cause an additional source of current noise.
Experimental Study Wind Turbine Performance of Straight-Savonius and Ice-Wind Type on the Similar proportion Aspect Ratio
Authors: Lillahulhaq Z , Muchyiddin A , Suhadak R W , Amirullah I , Sandy F D , Embot A C
Published: December 2021

The Performance of wind turbines at low speed can be improved by Ice-Wind model, particularly in self-starting conditions. Compared to a traditional wind turbine with two blades of the similar area and material, Ice-Wind can increase efficiency by 19%. Research on the Savonius turbine, particularly the Ice-Wind turbine, is challenging. It is because it has many restrictive parameters, such as the height, diameter, and area of the turbine blades. The Ice-Wind turbine shape is obtained by cutting a Savonius turbine. This process led to research on Ice-Wind turbines only under the similar parameters. The aspect ratio of a Savonius turbine has a significant effect on the speed, mechanical power and static-torque produced by the wind turbine. The research was done on Savonius and Ice-Wind turbines with the similar aspect ratio. The results show that the speed, power factor and efficiency of the Savonius turbine are higher than those of Ice-Wind. However, Savonius produces a smaller static-torque coefficient value than Ice-Wind. The results of this research contrast with other studies comparing Savonius and Ice-Wind turbines. In other researches, Savonius and Ice-Wind turbines have the similar area but different aspect ratios.
Effect of Welding Groove and Electrode Variation to the Tensile Strength and Macrostructure on 304 Stainless Steel and AISI 1045 Dissimilar Welding Joint Using SMAW Process
Authors: Suheni  , Rosidah A A , Ramadhan D P , Agustino T , Wiranata F F
Published: December 2021

AISI 1045 and 304 stainless steel are widely used in automotive and industrial fields However, both of these steels have their own advantages and disadvantages. AISI 1045 is not resistant to corrosion but has good wear resistance and low price. Meanwhile, the 304 stainless steel provides good corrosion resistance and mechanical properties but is costly. Their combination is able to provide a good property and reduce the costs. Thus, in order to combine these two metals, shield metal arc welding is carried out using welding groove and electrode variation. The groove variations used were double bevel, V, and double V-groove, additionally, the electrode variations used were E6013 and E7016. Then, the welding results were characterized using the tensile strength and macrostructure analysis. The results revealed that the specimen using E7016 electrode for the double V-groove resulted in the highest tensile test results the value of 270.48 MPa yield strength, 411.49 MPa tensile strength, and 19.81% elongation. The macrostructure analysis showed that the specimens using E7016 electrode gave a narrow HAZ that led to higher mechanical properties.
Increased Resilience Using Close Loop Renewable Microgrids in the Surabaya Distribution System as a Self-Healing Application
Authors: Putra D F U , Soeprijanto A , Penangsang O , Delfianti R , Rohiem N H , Putra N P U
Published: December 2021

Distribution system reconfiguration has two main objectives, namely as optimization of network operations and as system recovery in case of disturbances. It is necessary to consider the reconfiguration process and the process of using Distributed Generation (DG) or microgrid as an additional supply to reduce the possibility of failure, loss of power, or a voltage drop. Therefore the first step in research This results in the candidate bus 14 and bus 52 on the Mulyosari feeder which must be reconfigured by cutting off the flow at L13 and L50 because the losses on both buses are the worst with a value of 0.01370MW and 0.00900MW using the calculation algorithm of Binary Particle Swarm Optimization (BPSO) to predict the location of possible failures and the placement DG, and selected on bus 29 and bus 45 which were injected DG with a PV capacity of 15 kW each, after the self-healing was applied to the system, power flow analysis was carried out, and get good results g is very satisfactory with the total losses in the system decreased from 0.363MW to 0.116MW from this study we can conclude that self-healing can only be done if the distribution system is a complex radial.
Design of Rectangular Microstrip Antenna 1x2 Array for 5G Communication
Authors: Irfansyah A , Harianto B B , Pambudiyatno N
Published: December 2021

Microstrip antennas are currently popular because they have the advantage and meet the demand for small and lightweight antennas so that they are compatible and easy to integrate. This study aims to design an antenna microstrip rectangular 1x2 array, a rectangular patch microstrip antenna consisting of two elements. The antenna has a patch size of 19.5 mm x 26.5 mm array 1x2 with a frequency of 3.5 GHz. The antenna design is made in a simulation that works at a frequency of 3.5 GHz, and the substrate material is made of FR 4, which has a constant (ε
r of) of 4.3, while patch materials are made of copper. Calculating the value of the initial antenna parameters will be optimized by sweeping the parameters to obtain the desired return loss, VSWR, gain, bandwidth, and directivity. The results of optimization of the rectangular microstrip antenna design 1x2 array work at a frequency of 3.5 GHz with a return loss -12.54 dB in the frequency range 3. 47 GHz up to 3.53 GHz, bandwidth 66.5 MHz, VSWR value of 1.6 and produce a gain of 5.5 dB.
Fe-N/C Catalyst using Various Nitrogen and Carbon Ratio through Chemical Oxidative Polymerization
Authors: Setyowati VA , Widiyastuti W , Nurkhamidah S , Saidatin N , Lukdyantoro O
Published: December 2021

This study aims to explain the effect of variations in nitrogen and carbon composition of catalysts on electrochemical properties and physical characterization. The usage of non-precious metals supported by nitrogen-carbon is one alternative to reduce the amount of platinum as the innovation of energy materials. Iron is a transition metal that can increase catalytic activity with the addition of a nitrogen source. The polymerization process was carried out by chemical oxidative polymerization for 24 hours in an ice bath using aniline as N source. Optimization of nitrogen coating on the carbon surface is carried out by mixing carbon during polymerization. The mixing of iron precursor and N/C powder was carried out in an ultrasonic bath and continued with pyrolysis at a temperature of 700°C. Regarding Cyclic Voltammetry (CV) test, the Fe-N/C = 2/1 catalyst has the largest area and the highest current density. The presence of Fe2O3 is needed to improve the electrochemical properties compared to Fe3C compounds. The composition analysis showed that the Fe-N/C = 2/1 catalyst had the highest Fe content after pyrolysis. In addition, the Fe-N/C = 2/1 catalyst also had the highest nitrogen content which can form a nitrogen functional group from the pyrolysis process.
Hydrothermal Pretreatment of Rice Straw with Alkaline Addition for Enhancing Biogas Production in Semicontinuous Anaerobic Digester
Authors: Sato A , Widjaja A , Soeprijanto
Published: December 2021

This study presents the results of hydrothermal pretreatment of rice straw on its ability to improve the biogas production process in anaerobic digesters. Hydrothermal treatment on rice straw biomass was carried out with the addition of 0%, 3% and 5% NaOH (w/w rice straw) for one hour at a temperature of 140 °C. This study showed that hydrothermal and alkaline hydrothermal pretreatments were able to increase organic degradation of rice straw as indicated by an increase in the dissolution of lignin and hemicellulose from rice straw. Temperature and NaOH worked synergistically to dissolve lignocellulose in the hydrothermal pretreatment process. In the semicontinuous digester fed with pretreated rice straw, NaOH content in the pretreatment stage was found to give significant effect in enhancing biogas production. Average daily biogas production by the untreated rice straw, hydrothermal pretreated without NaOH addition, hydrothermally treated rice straw with 3% NaOH and 5% NaOH was 23.9, 57.1, 95.8 and 108.8 L/kg rice straw, respectively.
Numerical Investigation Aerodynamic Characteristic Installation I-65° Cylinder Type Upstream Bluffbody as Airflow Passive Control
Authors: Sakti G , Cahyo B G , Wulansari A , Regia A , Dharma I A
Published: December 2021

This report is the basic research that focuses on efforts to reduce the drag force of a cylindrical pipe by placing an interfering cylinder in the area of the incoming flow direction. The aerodynamic behavior of the central cylinder and its disturbances were modeled in 2D are discretized in laminar flow by Finite Volume Methode using Ansys Fluent®. Efforts to reduce the drag force are carried out with the main cylinder diameter D=60 mm and the interfering cylinder type I-65° with diameter d/D = 0.125. The distance between the center points of the two cylinders being s/D=1,4 and Reynold number Re = 5.3 x 10

4
at a speed of U∞=14 m/s. Numerical simulation using variations of turbulent models k-epsilon (2eq),
k-omega (2eq), and transition k-kl-omega (3eq). The results of this research can show better aerodynamic performance. Placing the cylinder I-65° in tandem can reduce the average drag force coefficient by 68% at 700-800 timesteps. In contrast, the average lift coefficient decreased by 13% at the same timestep. The results were obtained with transition k-kl-omega (3eq) turbulence models that have been validated and able to approach the referenced experimental data.
Steady State Thermal Effect on Static Characteristic of Copper Roller Shaft
Authors: Marliana E , Utomo G P , Fuad S , Arifin A A
Published: December 2021

The static analysis of a copper roller shaft is performed. The copper roller shaft consists of bushing, pen roll and roller. All of those components g4bconsist of different materials. Thermal steady state and statical analysis is performed in order to investigate the thermal effect of high temperature copper slab on the roller shaft. The copper slab temperature is 1200OC. Based on this work obtained that the maximum total deformation is 0.0050523 m, maximum equivalent stress is 41600 MPa, maximum life cycle is 1011, total heat flux maximum is 879910 W/m2and the maximum damage occur in the pen roll component.
Functionalization of Multiwall Carbon Nano-Tube Supported Zinc Oxide Solid Acid Catalyst Using Sulfonate Compound for Transesterification of Schleichera Oleosa L Oil
Authors: Asri N P , Saraswati R , Yogasuara R R , Puspitasari D A , Mirzayanti Y W , Udyani K , Suprapto
Published: December 2021

Biodiesel is an alternative energy obtained through the trasesterification of vegetable oil in the presence of a catalyst. The catalyst plays a very important role in the success of the transesterification process. One way to increase the activity of the catalyst is through chemical modification called functionalization, which generally using SO3 group as a sulfonating agent is known as the sulfonation process. However, the disadvantage of this process is that it uses strong acids which are corrosive, require high temperatures and are not environmentally friendly. This study aims to increase the activity of zinc oxide catalyst supported by multi-wall carbon nano tube (Z/MWCNTs) sulfonated using (NH4)2SO4 as sulfonating agent. The synthesis route includes co-precipitation, sulfonation and precipitation time. The effect of concentration of ammonium sulfate, co-precipitation time, and sulfonating time on yield of biodiesels of kesambi (Schleichera oleosa L) oil (OSOBD) was investigated. The result showed that the activity functionalized Z/MWCNTS catalyst (Z/s-MWCCNTs) could enhance significantly. The results of the catalyst activity test on transesterification of OSO into biodiesel showed that Z/s-MWCNTs gave a high yield of 91% for the functionalized catalyst using ammonium sulfate with a concentration of 35%, co-precipitation time 12 hours and sulfonation time 4 hours. The functionalization of MWCNTS with the sulfonation process using ammonium sulfate has the potential to increase catalyst activity and can increase the efficiency of the transesterification process for non-edible oils, especially kesambi oil.
Designing Open Channel Dimension for Imkasu Area West Papua
Authors: Sari A S , Cahyono Y D G , Johnson N N A , Simorangkir D , Redanto F A , Putri R H K , Utamakno L
Published: December 2021

Gag Nikel Ltd belongs to a Contract of Work located in Gag Island, West Waigeo Islands District, Raja Ampat Regency, West Papua Province. The open pit mining system employed at this company will enter the mining location and therefore, requires a design of open channel for diversing water coming from rainfall, run off, and ground. The rainfall intensity calculated by Mononobe formula obtained 5,994 mm / hour, whereas the catchment area got 0.59 km 2. The total discharge of run off calculated by Rational Formula gained 1867,956 m 3 / hour. Meanwhile, the design of open channel calculated by Manning Formula yielded wet section (A) = 0.668 m 2, base width (b) = 0.714 m, and depth (h) = 0.714 m, surface width (B) = 1.542 m. Box control having the volume 1 m3, length = 1 m, width = 1 m, and height 1 m must be made every 1 kilometer of open channel length. Around the area of open channel, the used tire must be given to reduce the erosion rate flowing into settling pond. All of these are necessary because the open channel is located near the natural channel and we must also consider several regulations such as Presidential Decree and IPPKH adjusted to the technical study that has been designed.
Quantitative Model of Optimization on Non-Oil Based Fuel Alternative Energy
Authors: Sutejo B , Oktavera R
Published: December 2021

Research of “Quantitative Model of Optimization On Non-Oil Based Fuel Alternative Energy” is using goal programing method approach which will generate comprehensive mathematic models to determine policy on alternative energy field beside oil based fuel. The result of the research is sensitivity analytic model and optimization model of nonoil based fuel alternative energy. Developed model is goal programing to optimise alternative energy beside oil based fuel. Model implementation conducted on alternative energy are coal, nature gas and hydro. And the calculation result using Expert Choice Version 9.0 is obtained that coal as alternative energy has relative priority value of 36,8% at overall consistency index 0,04 or 4%. Optimization implemented model conducted at alternative oil based energy plan using calculation of Quantitative System 3.0 program conclude that coal = 9.809274, gas = 0.8409028, hydro = 0. Minimal objective = 18.69225
Rheological properties of sewage sludge ash ceramic masses
Authors: Shakhov S A , Yu Nikolaev N
Published: December 2021

Industrial wastes are widely involved in the building ceramic production. Sewage sludge ashes are promising secondary sources for building ceramics production. However, sewage sludge ash application for building ceramic materials production is limited by unsatisfactory molding properties. According to modern concepts, coagulation structure formation processes can be controlled by adjusting ceramic mass compositions by highly dispersed modifying additives. In this study, the drinking water treatment sludge filtrate generated in pumping and filtering stations was used as a highly dispersed additive. The purpose of study was to assess the drinking water treatment sludge filtrate effect on rheological properties of ash-clay molding mixtures.

Using the photo sedimentation analysis, X-ray phase analysis, calorimeter method and parallel-shifting plate plastometry the drinking water treatment sludge filtrate additive effect on rheological properties of ash-clay mixtures was established.

It was found that ash-clay mixture modification with the drinking water treatment sludge filtrate promotes a slow elastic deformations percentage increase from 3-17% to 7-34%. Apparently, this is due to the drinking water treatment sludge filtrate highly dispersed particles adsorption on coarse ash and clay particles that promotes the growth of their hydrophilic properties. Ash-clay mixtures molding properties improvement makes it possible to increase the ceramic blanks density.
Method for assessing the effect of self-healing of asphalt concrete with encapsulated modifier
Authors: Inozemtcev S S , Do T T , Korolev E V
Published: December 2021

A unified methodology for assessing the ability of a material to heal itself does not exist at present. It is due to the absence of criteria characterizing the ability of a material to independently respond to conditions in a controlled manner and to take measures to eliminate an adverse effect on the properties or structure of the material. Usually, the self-healing ability is assessed using the coefficient of relative change of a measured indicator (for example, strength), which does not allow for two parameters: residual strength, which depends on the number of not broken bonds after the test, and the binder’s own potential for recovery. The paper proposes a method for calculating the healing efficiency, taking into account the relative difference in the loss of strength, material with the use of an encapsulated modifier and without it. The proposed recovery factor reflects the effect of the encapsulated modifier on the change in the strength of the composite under study; therefore, to assess the efficiency of a self-healing material, it is also necessary to take into account the properties in the initial period of time and their stability under operating conditions. The problem of choosing the optimal indicator of material properties for assessing the recovery effect and improving the calculation method taking into account the duration of the recovery period is not solved and requires additional large-scale studies.
Applicability of X-ray computed tomography for concrete cellular structure analysis
Authors: Lebedev M S , Kozhukhova M I , Voitovich E V
Published: December 2021

Nowadays, the researchers of materials sciences area, use direct and indirect methods such as microscopy, porosimetry, etc. for studying structural characteristics of materials. X-ray computed tomography is among one of the modern and widely used research analytical methods that provides 3D images of solid materials without any preliminary preparation, such as crashing of sample, and violation of its structural integrity. To demonstrate the potential possibilities of X-ray computed tomography, in this research matrices with cellular structure using portland cement-based cellular concrete was studied as an example. The study showed that the pore structure of cellular concrete is dominated by capillary pores with a diameter of up to 200 um. The majority of pores did not exceed 1.6 mm in diameter, that formed during the foaming process. The calculated average size of the volumetric distribution of air voids was 0.95 mm. About 80% of large pores of a cellular concrete specimen with an average size of about 1 mm determines high porosity of the composite which is consistent with its average density values. The study of interpore structure partition using X-ray computed tomography allows for evaluation the difference in thickness from 10 um to 0.6 mm in the zones of “confluence” of large pores. The porosity of cement matrix, including individual pores with sizes from -30 to 250 um, was about 16.5%. The cement matrix is dominated by the products of cement hydration with capillary and “gel” pores. There are few nonreacted cement particles that are evenly distributed throughout the volume of the composite. To obtain more complete information about the structure of cellular concrete or any other composite, it is necessary to perform complex studies applying not only X-ray computer tomography technique, also scanning electron microscopy for evaluation of chemical analysis to identify mineral phases present and correlate them with absorption intensity of X-ray radiation on tomographic images.
Development of structural-heat-insulating lightweight concrete composition using production of aerated concrete waste as a porous aggregate
Authors: Leontev S V , Kharitonov V A
Published: December 2021

Annually enterprises in the field of manufacturing of products from aerated concrete generate from 5000 to 10000 m3 of solid production waste. One of the perspective and under-investigated direction is the practical application of solid waste using a porous aggregate in structural-heat-insulating lightweight concrete in the production of construction materials. The aim of this study was to evaluate the possibility of using crushed aerated concrete as a large aggregate in lightweight concrete for structural and thermal insulation purposes and to establish optimal conditions for obtaining products with the best characteristics. There were defined the qualitative indicators of crushed aerated concrete, analyzed factors influencing on the preservation of the properties of concrete in time, selected the composition of concrete aggregates from crushed concrete, studied the structure and properties of the obtained samples in the research. It has been found that to obtain effective constructive insulating lightweight concrete using waste production of aerated concrete as an aggregate is possible due to the fractionated pre-treatment of the aggregate with water dispersion of deep-penetration acrylic copolymers, insertion excess sealing water to concrete mixture, including optimization of the rheological properties of the concrete mix due to insertion of polycarboxylate hyperplasticizer.