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Glycine-nitrate combustion engineering of neodymium cobaltite nanocrystals

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Rare Metals 2021年第7期40卷 1778-1784页

作者： Ekaterina Alekseevna Tugova Oleg nikolaevich Karpov New Inorganic Materials Laboratory Ioffe InstituteSaint-Petersburg 194021.Russia Department of Physical Chemistry Saint Petersburg Electrotechnical University“LETT”Saint-Petersburg 197376Russia

NdCoO_(3)nanocrystals formed via glycine-nitrate combustion method followed by heat treatment has been systematically *** of NdCoO_(3)nanocrystals with minimal size of 7-10 nm from X-ray amorphous combustion products has been elucidated to be a very rapid process,occurring at the temperature of 550-600℃for5-30 *** comparison of the minimum sizes of NdCoO_(3)crystallites obtained from the offered empirical relation dmin=lunit cell·N(where N is 7-12 and‘unit cellis elementary cell parameter)and the data determined on the basis of X-ray diffraction(XRD)and transmission electron microscopy(TEM)showed good *** existence of special nanoporous microstructure and spatial limitations prevent NdCoO_(3)particle *** kinetic equation based on Avrami-Erofeev nucleation model was offered to be correlated well with experimental data of fractional conversion(a)versus isothermal time(s).The apparent activation energy(Ea=(338±32)kJ)of formation of NdCoO_(3)nanocrystals from X-ray amorphous combustion products obtained in excess of oxidant followed by heat treatment at 550-600℃was determined.

关键词： Rare earths Perovskite Kinetics Mechanism Combustion synthesis Nucleation

Reconstruction of the Indigenous Sources of Gold of the Glu-Kharinsky Placer (Kolyma River Basin, Magadan Region, Russia)

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Natural Resources 2022年第12期13卷 225-241页

作者： Natalya Evgenievna Savva aleksandr aleksandrovich Biruykov Anton nikolaevich Gluhov Shilo North-East Interdisciplinary Scientific Research Institute Far Eastern Branch of the Russian Academy of Sciences Magadan Russia

A comparative analysis of typomorphic features of gold placers and indigenous sources of gold was carried out for the Glukharinsky ore-placer node (the Nadezhda deposit and Glukharinskoye, Tyomnoye, and Tyi-Jurye ore occurrences). A correlation between fineness of placer native gold and composition of relic minerals preserved inside gold particles was obtained for the first time. This made it possible to establish mineral parageneses of native gold from potential indigenous sources. The study of placer gold fineness in combination with com-position of mineral inclusions allowed us to identify seven types of gold paragenesis: petzite-hessite with a fineness of 855‰, pyrite-polybasite-galena (a fineness of 670‰), bismuth telluride (900‰), cosalite-vikingite (790‰), galena (870‰), glaucodot (950‰), and hydrohematite (840‰). It was also shown that the placer contains the material from ore occurrences of different formation: gold-quartz-porphyry occurrences in granitoids (Au-Te-Bi type) and gold-silver occurrences. The method developed by us allows one to estimate the percentage of each ore source in placer formation.

关键词： Ore-Placer Node Native Gold Mineral Associations Placer Indigenous Sources

Search for giant pulses of radio pulsars at frequency 111 MHz with LPA radio telescope

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Research in Astronomy and Astrophysics 2018年第8期18卷 71-82页

作者： Andrey nikolaevich Kazantsev Vladimir Alexeevich Potapov E N.Lebedev Physical Institute of the Russian Academy of Sciences Pushchino Radio Astronomy ObservatoryPushchino 142290Russia

We have used the unique low frequency sensitivity of the Large Phased Array （LPA） radio telescope of Pushchino Radio Astronomy Observatory to collect a dataset consisting of single pulse observations of second period pulsars in the Northern Hemisphere. During observation sessions in 2011- 2017, we collected data on 71 pulsars at a frequency of 111 MHz using a digital pulsar receiver. We have discovered Giant Radio Pulses （GRPs） from pulsars B0301＋09 and B 1237＋25, and confirmed earlier reported generation of anomalously strong （probable giant） pulses from B 1133＋16 in a statistically significant dataset. Data for these pulsars and from B0950＋08 and B 1112＋50, earlier reported as pulsars generating GRPs, were analyzed to evaluate their behavior over long time intervals. It was found that the statistical criterion （power-law spectrum of GRP distribution of energy and peak flux density） seems not to be strict for pulsars with a low magnetic field at their light cylinder. Moreover, spectra of some of these pulsars demonstrate unstable behavior with time and have a complex multicomponent shape. In the dataset for B0950＋08, we have detected the strongest GRP from a pulsar with a low magnetic field at its light cylinder ever reported, having a peak flux density as strong as 16.8 kJy.

关键词： stars neutron - pulsars general - pulsars individual (PSR B0301+19 PSR B0320+39 PSR B0329+54 PSR B0809+74 PSR B0950+08 PSR B1112+50 PSR B1133+16 PSR B1237+25) - pulsars giant pulses individual pulses

Thermal state calculation of chamber in small thrust liquid rocket engine for steady state pulsed mode

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Chinese Journal of Aeronautics 2019年第2期32卷 253-262页

作者： Alexey Gennadievich VOROBYEV Svatlana Sergeevna VOROBYEVA Lihui ZHANG Evgeniy nikolaevich BELIAEV Department of Rocket Engines Moscow Aviation Institute School of Astronautics Beihang University

This paper presents a method of thermal state calculation of combustion chamber in small thrust liquid rocket engine. The goal is to predict the thermal state of chamber wall by using basic parameters of engine: thrust level, propellants, chamber pressure, injection pattern, film cooling parameters, material of wall and their coating, etc. The difficulties in modeling the startup and shutdown processes of thrusters lie in the fact that there are the conjugated physical processes occurring at various parameters for non-design conditions. A mathematical model to predict the thermal state of the combustion chamber for different engine operation modes is developed. To simulate the startup and shutdown processes, a quasi-steady approach is applied by replacing the transient process with time-variant operating parameters of steady-state processes. The mathematical model is based on several principles and data commonly used for heat transfer modeling: geometry of flow part, gas dynamics of flow, thermodynamics of propellants and combustion spices, convective and radiation heat flows, conjugated heat transfer between hot gas and wall, and transient approach for calculation of thermal state of construction. Calculations of the thermal state of the combustion chamber in single-turn-on mode show good convergence with the experimental results. The results of pulsed modes indicate a large temperature gradient on the internal wall surface of the chamber between pulses and the thermal state of the wall strongly depends on the pulse duration and the interval.

关键词： Combustion chamber Film cooling Mathematical model Nonstationary thermal mode Small thrust liquid rocket engine Steady pulse mode Thermal state

Kinetics and mechanism of natural wolframite interactions with sodium carbonate

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International Journal of Minerals,Metallurgy and Materials 2019年第11期26卷 1364-1371页

作者： Evgeniy nikolaevich Selivanov Kirill Vladimirovich Pikulin Lyudmila Ivanovna Galkova Roza Iosifovna Gulyaeva Sofia aleksandrovna Petrova Institute of Metallurgy of the Ural Branch of the Russian Academy of Sciences

The kinetics and mechanism of natural wolframite interactions with sodium carbonate during air heating were studied.X-ray phase and X-ray microanalysis were used to establish that the initial monocrystalline wolframite consists of Fe0.5 Mn0.5 WO4 and Fe0.3 Mn0.7 *** thermal analysis showed that the interaction of wolframite with sodium carbonate begins above 450°C with the formation of tungstate,sodium ferrite,iron oxides,and *** experiments on sintering with the subsequent removal of water-soluble compounds(leaching)tracked the change in the structure of *** atomic ratio of Fe/Mn in wolframite does not change up to 600°C,and subsequently decreases to 0.2 during heating,which allows the mechanism of the process to be identified and indicates the greater reactivity of wolframites with an increased proportion of *** analysis with data processing using non-isothermal kinetics established that the interaction of wolframite with sodium carbonate in an air stream proceeds via a two-stage mechanism,wherein the first stage is limited by diffusion(activation energy,E=243 kJ/mol)and the second stage is limited by autocatalysis(activation energy,E=212 k J/mol)due to the formation of a Na2 WO4–Na2 CO3 eutectic.

关键词： wolframite structure sodium carbonate sintering thermal analysis kinetics

A system-integrated approach for the design of tourist areas at the local level under changing conditions:A case study in the Altay Mountains

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Regional Sustainability 2024年第2期5卷 89-102页

作者： Alexandr nikolaevich DUNETS Evgeniya Mikhailovna TABAKAEVA HAN Fang Department of Scientific and Innovative Development Altai State UniversityBarnaul656049Russia Department of Recreational Geography ServiceTourism and HospitalityInstitute of GeographyAltai State UniversityBarnaul656049Russia State Key Laboratory of Desert and Oasis Ecology Key Laboratory of Ecological Safety and Sustainable Development in Arid LandsXinjiang Institute of Ecology and GeographyChinese Academy of SciencesUrumqi830011China

The existing approaches for the design of tourist areas often lead to limited flexibility in project *** realize a more flexible approach,in this study,we formulated a model for planning and designing tourist areas at the local ***,specific tools for analyzing tourist areas and ensuring sustainable development under changing conditions were *** study was conducted in two tourist regions,Biryuzovaya Katun tourist complex and Belokurikha destination(including Belokurikha City with Belokurikha 2 Gornaya tourist complex and surrounding areas),in the Altay *** employed the recreation opportunity spectrum and proposed a system-integrated programming approach for the design of tourist areas at the destination and site *** key of this approach was the collection and analysis of current spatial data,including the spatial distribution of attractions and visitor *** constructed heat maps using video recording and unmanned aerial vehicle(UAV)observation ***,we analyzed the video stream using an image-analyzing framework You Only Look Once(YOLO)v5 *** heat map of visitor flows based on video recording data in the Andreevskaya Sloboda museum of Belokurikha 2 Gornaya tourist complex allowed us to highlight the most attractive sites in this area and classify them into one of three types:points of functional concentration,points of transitional concentration,and points of *** heat maps in Biryuzovaya Katun tourist complex,created using UAV observation data,allowed us to determine the spatiotemporal patterns of visitor flows and tourists’preferences throughout the day within four time intervals:09:00-12:00,13:00-14:00,14:00-15:00,and 16:00-18:00(LST).The maximum visitor flow density occurred from 16:00 to 18:00 in the beach area of the artificial lake.A comparison between the visitor-concentrated sites and the current facilities provided insights into the demand for attractions and facilities and

关键词： Tourism planning Tourist areas Unmanned aerial vehicle(UAV) Visitor flows Heat map Altay Mountains

Influence of relative compaction and degree of saturation on the deformation characteristics of bentonite under freeze-thaw cycles

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Research in Cold and Arid Regions 2023年第4期15卷 161-170页

作者： Hao Wang Xu Li WenShao Xin Vladimir nikolaevich Paramonov XueWen Zhao Department of Civil Engineering University of OttawaOttawaON K1N6N5Canada Key Laboratory of Urban Underground Engineering of Ministry of Education Beijing Jiaotong UniversityBeijing 100044China Emperor Alexander I St.Petersburg State Transport University St.Petersburg 190031Russia Qingdao Transportation Planing and Design Institute Co. Ltd.QingdaoShandong 266043China

Bentonite,consisting of clay minerals of the montmorillonite group,has been widely used as an adsorbent and backfill material in nuclear waste disposal and groundwater *** is challenging to use bentonite as a filling material in cold regions since bentonite is highly sensitive to thermal environmental changes,during which its bulk volume and microstructure change *** this study,a series of one-dimensional and three-dimensional freeze-thaw tests were carried out within a closed system to investigate the influencing factors of the deformation of bentonite under freeze-thaw *** show that the initial soil water content greatly impacts bentonite's deformation during freeze-thaw *** an initial higher degree of saturation(Sr),the expansion caused by the formation of ice lenses has a greater impact than the shrinkage induced by dehydration,ice-cementation,and so ***,bentonite tends to shrink at a lower degree of saturation during *** the critical degree of saturation that determines bentonite's behavior of frost heave or frost shrinkage seems to be roughly *** the number of freeze-thaw cycles rises,initially uncompacted bentonite clay becomes more compacted,and initially compacted bentonite clay remains unchanged.

关键词： Bentonite Relative compaction Degree of saturation Freeze-thaw cycles Deformation

Theory and Practice of Heat Transfer in Electric Arc and Flare Furnaces and Power Plants

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World Journal of Engineering and Technology 2020年第4期8卷 739-755页

作者： Anatoliy nikolaevich Makarov Department of Electrical Supply and Electrical Engineering Tver State Technical University Tver Russia

The author describes the fundamental laws of physics, the laws of thermal radiation of ionized and non-ionized gas volumes. Based on open laws, a modern theory of heat transfer and methods for calculating heat transfer in electric arc and flare metallurgical furnaces, furnaces of steam boilers, and combustion chambers of gas turbine plants of power plants have been developed. The use of scientific discovery makes it possible to create innovative electric arc steel-smelting furnaces, flare heating furnaces, and combustion chambers in which the consumption of electricity and fuel is reduced, productivity and service life are increased, and the amount of harmful emissions into the environment is reduced.

关键词： Heat Transfer Thermal Radiation Electric Arc Torch Furnaces Fire Cham-bers Combustion Chambers

Photon and Graviton: Similarity and Distinctions

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Journal of High Energy Physics, Gravitation and Cosmology 2022年第4期8卷 1110-1126页

作者： Andrey nikolaevich Volobuev Department of Physics Samara State University Samara Russia

Two elementary particles—a photon and a graviton—responsible for interaction with physical objects of two long-range action fields electromagnetic and gravitational are considered. The similarity and distinction of these quantum particles are investigated. It is shown that these particles essentially differ from each other. First of all, they are in different spaces. The photon is in photon space, and the graviton is in Riemann’s space-time. Interaction of a photon and a mass body cannot be calculated in Euclidian space. Interaction of a graviton and a mass body can be calculated in the Euclidian space. Polarizing properties of a gravitational wave both in plane Minkowski’s space, and in curved Riemann’s space-time are in detail considered. The differential equation of a gravitational quantum oscillator is found and its solution is analyzed. Also, the quantum metrics of Riemann’s space-time in presence of graviton and its quantum numbers are found.

关键词： Photon Graviton Gravitational Wave Riemann’s Space–Time Scalar Curvature Polarization Quantization Metric Tensor