bluuebunny/crossref_metadata_2025 huggingface dataset:
Interactions of multiple three-dimensional nonlinear high frequency magnetosonic waves in magnetized plasma
Authors: Ishaq Muhammad , Xu Hang , Sun Qiang
Published: July 2020

The interaction of three-dimensional nonlinear high frequency magnetosonic waves in a magnetized plasma is investigated theoretically via the nonlinear Kadomtsev–Petviashvili equation. Though such wave patterns are commonly observed in the solar system and can be generated by magnetic resonance generators, only limited theoretical studies have been performed. We examined the existence of both periodic and solitary solutions of magnetosonic waves by using the modulation instability analysis. The Phillips wave resonance criterion is employed for capturing the periodic wave interaction whose energy conversion is analyzed via Fourier spectra. It is found that more energy is carried by the primary wave relative to that by the higher-order harmonic wave. In addition, it is noted that the rhodonea curve is smooth and closed for rational wavenumbers, but it becomes chaotic to form a dense set for irrational ones. We believe that this work can fill the blanks in the research of magnetosonic wave behaviors in the magnetized plasma.
Young people in Australian residential aged care: evaluating trends from 2008 to 2018
Authors: Brown Mark G. , Bishop Glenda M. , Winkler Di , Douglas Jacinta M.
Published: July 2020

ObjectiveOver the past decade, various programs and reforms have targeted the issue of people aged <65 years living in ‘permanent’ residential aged care (PRAC). As context for ongoing policy discourse, the aim of this study was to evaluate trends in rates of young people entering and leaving PRAC from 2008 to 2018.
MethodsCounts of people aged <65 years entering, remaining in and exiting PRAC were obtained from the National Aged Care Data Clearinghouse. Age standardisation was used to control for changes in the age and size of the Australian population. Annual age-standardised rates of admissions (subtracting transfers) and exits to the community were calculated. Linear regression models tested for a sustained increase or decrease in age-standardised rates nationally and within state and age subgroups.
ResultsNotwithstanding year-to-year variation, neither admissions (subtracting transfers) nor exits to the community showed statistically significant increasing or decreasing trends in the national age-standardised rates. Admission rates varied by age and state.
ConclusionsMany more young people are admitted to PRAC each year than return to community living, with no sustained change between 2008 and 2018 at the national level. Age standardisation is crucial for evaluating systemic population-level change regarding younger people in PRAC.
What is known about the topic?As at June 2018, over 6000 people aged <65 years still live in PRAC in Australia. Previous research has demonstrated that this cohort experiences a much poorer quality of life on average than people of similar age and disability who reside in other community settings. Various strategies for improving outcomes have been trialled, many aiming to reduce the number of younger people living in aged care; the National Disability Insurance Scheme (NDIS) also has this among its aims.
What does this paper add?This paper reports trends in the number of young people entering and exiting aged care, after statistically controlling for changes due to population growth and aging. The paper highlights that national admission rates did not increase or decrease in a sustained manner, and that most of those admitted never return to community living before turning 65 years of age.
What are the implications for practitioners?Programs and policies aimed at reducing the number of young people in aged care must grapple with the scale of the issue and its apparent resistance to amelioration over the past 10 years. The results of this study provide a benchmark against which to judge the future impact of the NDIS.
Different levels of rainfall and trampling change the reproductive strategy of Kobresia humilis in the Qinghai-Tibet Plateau
Authors: Peng Zhen , Xiao Hong , He Xiang , Xu Changlin , Pan Taotao , Yu Xiaojun
Published: July 2020

The sedge Kobresia humilis (C.A. Mey. ex Trautv.) Serg. is the dominant plant in the alpine meadows of China’s Qinghai-Tibet Plateau, which has experienced substantial grassland degradation due to reduced rainfall and overgrazing. In this study we sought to determine the reproductive strategy of K. humilis under three levels of rainfall and seven levels of trampling by Tibetan sheep and yaks with a two year simulation trial on the Plateau. With a reduction in rainfall and an increase in trampling intensity, there was a decrease in sexual reproduction indices, plant height and single leaf number. The highest rainfall promoted sexual reproduction, whereas average rainfall was conducive to vegetative reproduction, and the lowest rainfall inhibited reproduction. The reproductive strategy of K. humilis could be judged according to the average rainfall from July to August. Notably, after two years of low rainfall and a heavy trampling treatment, K. humilis produced more seeds with smaller size. The rainfall presented a two-way regulation function in the trampling effect on K. humilis reproductive characteristics.
Feasibility study of range verification based on proton-induced acoustic signals and recurrent neural network
Authors: Yao Songhuan , Hu Zongsheng , Zhang Xiaoke , Lou En , Liang Zhiwen , Wang Yuenan , Peng Hao
Published: July 2020

Range verification in proton therapy is a critical quality assurance task. We studied the feasibility of online range verification based on proton-induced acoustic signals, using a bidirectional long-short-term-memory recurrent neural network and various signal processing techniques. Dose distribution of 1D pencil proton beams inside a CT image-based phantom was analytically calculated. The propagation of acoustic signal inside the phantom was modeled using the k-Wave toolbox. For signal processing, five methods were investigated: down-sampling (DS), DS + HT (Hilbert transform), Wavelet decomposition (Wavedec db1, db4 and db20). The performances were quantitatively evaluated in terms of mean absolute error, mean relative error (MRE) and the Bragg peak localization error (

Δ

B
P

). In addition, the study analyzed the impact of noise levels, the number of sensors, as well as the location of sensors. For the noiseless case (32 sensors), the Wavedec db1 method demonstrates the best performance:

Δ

B
P

 

is less than one pixel and the dose accuracy over the region adjacent to the Bragg peak (MRE50) is ∼3.04%. With the presence of noise, the Wavedec db1 method demonstrates the best noise immunity, achieving

Δ

B
P

 

less than 1 mm and an MRE50 of ∼12%. The proposed machine learning framework may become a useful tool allowing for online range verification in proton therapy.
Rapidly formed stable and aligned dense collagen gels seeded with Schwann cells support peripheral nerve regeneration
Authors: Muangsanit Papon , Day Adam , Dimiou Savvas , Ataç Altay Frederick , Kayal Céline , Park Hyeree , Nazhat Showan N , Phillips James B
Published: July 2020

Objective. Gel aspiration-ejection (GAE) has recently been developed for the rapid production of dense, anisotropic collagen gel scaffolds with adjustable collagen fibrillar densities. In this study, a GAE system was applied to produce aligned Schwann cells within a type-1 collagen matrix to generate GAE-engineered neural tissues (GAE-EngNT) for potential nerve tissue engineering applications. Approach. The stability and mechanical properties of the constructs were investigated along with the viability, morphology and distribution of Schwann cells. Having established the methodology to construct stable robust Schwann cell-loaded engineered neural tissues using GAE (GAE-EngNTs), the potential of these constructs in supporting and guiding neuronal regeneration, was assessed both in vitro and in vivo. Main results. Dynamic mechanical analysis strain and frequency sweeps revealed that the GAE-EngNT produced via cannula gauge number 16 G (∼1.2 mm diameter) exhibited similar linear viscoelastic behaviors to rat sciatic nerves. The viability and alignment of seeded Schwann cells in GAE-EngNT were maintained over time post GAE, supporting and guiding neuronal growth in vitro with an optimal cell density of 2.0 × 106 cells ml−1. An in vivo test of the GAE-EngNTs implanted within silicone conduits to bridge a 10 mm gap in rat sciatic nerves for 4 weeks revealed that the constructs significantly promoted axonal regeneration and vascularization across the gap, as compared with the empty conduits although less effective regeneration compared with the autograft groups. Significance. Therefore, this is a promising approach for generating anisotropic and robust engineered tissue which can be used with Schwann cells for peripheral nerve repair.
Spectral analysis of gas-dynamic processes in the intake system of a supercharged piston engine
Authors: Plotnikov L V , Kochev N S , Osipov L E
Published: July 2020

The study of gas-dynamic processes in gas-air systems of engines in order to improve the processes of gas exchange, mixture formation and combustion is an urgent task. The results of experimental studies of gas-dynamic processes in the intake system of an engine with turbo-compressor are presented in the article. A brief description of the setup and methods of experiments is presented. A spectral analysis of functions was chosen as a tool for monitoring gas-dynamic phenomena in different systems. A comparative analysis of the amplitude spectra of the pulsations of the velocity and pressure of the flows in the intake system of the engine with and without a turbo-compressor is presented in the article. The installation of a turbo-compressor leads to a significant change in the structure of gas flows in the intake system. A method for stabilizing the pulsating flow in the intake system by installing a leveling grid in the output channel of the compressor is proposed. It has been established that the presence of a leveling grid in the intake system of an engine with turbo-compressor leads to a decrease in the low-frequency amplitudes of the velocity pulsations and the pressure of the flow by up to 30%.
Aerodynamics, convective heat exchange and energy efficiency of cyclone devices with large relative length
Authors: Onokhin D A , Orekhov A N , Karpov S V , Konoplev M I
Published: July 2020

The main purpose of the work was to optimize the design of the cyclone devices with large relative length. Studies of aerodynamics and convective heat exchange in cyclone devices have been performed to determine their optimal parameters. Two methods for determining the aerodynamic and thermal efficiency of cyclone chambers are proposed. The analysis according to the proposed methods was carried out and the optimal geometrical and regime parameters of cyclone chambers were determined, ensuring minimal energy costs and an increase in efficiency.
Thermohydrodynamic processes of droplet evaporation and boiling on functional nanomaterials surfaces
Authors: Babenko D D , Dmitriev A S , Mikhailova I A
Published: July 2020

We study the evaporation and boiling of water droplets on functional nanomaterial surfaces. Methods for manufacturing samples of nanocomposites, methods for studying contact angles, and evaporation dynamics are described. New experimental data on the behavior of contact angles and evaporation rates at various temperatures for samples of nanocomposites are presented in both the constant contact line mode and the constant contact angle mode. The features of evaporation for nanocomposites with inclusions of boron nitride and aluminum nitride nanoparticles inside graphene samples are noted.
Development of renewable power generation in Russia: opportunities and risks from the climate perspective
Authors: Fedotova E V , Klimenko V V
Published: July 2020

The main trends of the renewable generation development are discussed both on the global and national scales. The climate-driven factors of renewable power development are addressed considering the climate change impact. A method of the long-term climate projection assessment is proposed. The forecast estimations of the precipitation amount and the surface wind speed are developed considering a difference between the climate scenarios. The robust output of the fulfilled analysis is a general climate tendency to some improvement of the renewable power operation conditions under all realistic climate projections. The main climate-related negative effect found is a wind speed decrease in the European part of Russia and southern West Siberia, which means that some adaptation measures should be kept in mind when planning renewable power construction in these areas.
Open source paradigm: a use case of the climate modelling for power engineering problems
Authors: Fedotova E V
Published: July 2020

The open source development paradigm was employed to develop a computational tool to process daily air temperature data. The computational workflow included data preprocessing, clustering procedure, as well calculation and visualization of the energy-related climate characteristics. Applicability of the developed tool was demonstrated considering an analysis of the regional features related to the heating and cooling energy demand indicators. It has been found that the considered locations have distinctively different patterns of the heating and cooling degree-days, despite of the very close values of the annual average temperatures.
Gradient heat flux measurement in study of heat transfer for condensation of water vapour on pipes
Authors: Mityakov V Yu , Zainullina E R , Babich A Yu , Mityakov A V
Published: July 2020

Heat transfer during condensation of saturated water steam on the outer surface of a pipe has been investigated by the method of gradient heat flux measurement. Heat flux per unit area and heat transfer coefficients obtained for vertical, horizontal and inclined pipe are presented. The optimum angle of inclination of the pipe (ψ = 30 °) was experimentally determined. High informational content of gradient heat flux measurement has been revealed, which opens up new possibilities for studies of heat transfer during condensation.
Research of heat transfer in combustion chamber of diesel engine on idle by gradient heat flux measurement method
Authors: Vintsarevich A V , Mityakov A V , Gerasimov D V , Yamashkin M V
Published: July 2020

Heat transfer research is one of key topics for internal combustion engine development. However, heat transfer study is a challenging task due to high value and rapid change in temperature and heat flux inside the combustion chamber. In this paper, experimental study is presented with implementation of heterogeneous gradient heat flux sensors. Heat flux was measured by a probe and at several points of a firedeck. Heat fraction to a firedeck was calculated at various engine speeds. The heat transfer coefficient at investigated points is calculated. Comparison with other studies is provided.
Discipline of “Thermal Physics of Nanostructures”
Authors: Khvesyuk V I , Yanushkin Yu M
Published: July 2020

Thermal physics of nanostructures is an important fundamental field in the development of nanotechnology. The study of thermal processes in nanostructures requires the developing of new physical models and new mathematical tools – statistical methods of analysis of heat transfer. This work presents the subject matter of the discipline of “Thermal Physics of Nanostructures” taught at BMSTU to prepare highly qualified specialists in this new field of science and technology.
Research of air-fluidized bed in the drying process of granulated hydrophobic polymers
Authors: Geller Yu A , Shatskikh Yu V , Antanenkova I S
Published: July 2020

This article studies the drying characteristics of granules of hydrophobic polymers. The hydrodynamics of a bed of PET granules has been studied taking into account the process of dust formation. On the basis of the data obtained, restrictions on the velocity gas movement through the granulate bed have been revealed to reduce dust formation at the same time preserving the quality of drying. The refined dependence of the hydraulic resistance of the bed of granules on the velocity of the gas has been obtained.
Thermodynamic analysis of the cycle efficiency of the utilization units for gas transmission systems
Authors: Antanenkova I S , Vetrenko A A
Published: July 2020

A schematic solution is proposed for organizing an auxiliary energy module that converts the thermal energy of the exhaust gases of the GTU, which serves as a drive for the gas compressor unit in a thermal power circuit on a low-boiling working fluid, into electrical energy (based on the technology of the organic Rankine cycle). The results of thermodynamic analysis of cycle efficiency on different working fluids (Rc318, R744, R245fa, R601, R290) are presented. The influence of the operating parameters of the cycle on the energy efficiency of the unit is studied.
Effect of the bounding walls configuration on draft water flow through staggered tube bank
Authors: Zasimova M A , Ivanov N G , Podmarkova A D , Ris V V , Tshur N A
Published: July 2020

The paper presents the numerical study of 3D unsteady buoyancy-induced water flow through a staggered tube bank typical for subsea cooling units used at seabed gas compression modules. For the Grashof number from the range of 105…106 parametric computations have been performed using direct numerical simulation of the draft water flow in the inter-tube space. For various arrangement of the bounding walls, the effect of the side flow on heat transfer is analyzed and discussed.
Condensation of water vapor in the presence of fluocarbons in the turbulent stream of liquid
Authors: Yezhov E V , Ponurovskaya V V , Kolotukhin S P , Mazurin I M
Published: July 2020

The paper presents an experimental study of condensation of pure water vapor and water vapor in the presence of octafluoropropane (C3F8) in a vapor-gas mixture (VGM) in a turbulent jet of liquid.
Research of horizontal single-row bundles of ribbon finned tubes at free convection
Authors: Novozhilova A V , Maryna Z G , Lvov E A , Vereshchagin A Yu
Published: July 2020

The intensity of free convection research leads to a wider understanding of the mechanisms and possibilities of using free-convection currents for the heat discharge or heatremoval in many industries, in energy processes, in a large number of devices or systems. Free convection significantly affects the maximum values of heat fluxes, and studying them becomes quite important for problems in which other methods of heat transfer are not applicable or uneconomical. The phenomena of free-convective heat transfer are quite complex, processes of conjugate heat transfer, for example, radiation and convection can be observed. Theoretical methods of description and calculation are used for bodies of simple shape: ball, plate, cylinder. The methods of theoretical analysis for heat transfer of bodies of complex shape are too voluminous and cumbersome. The intensification of free-convective heat transfer is possible through the use of various types of fins. To calculate the natural convective heat transfer of finned surfaces, the criterial dependencies of an empirical nature are mainly used. The article presents the results of a study of free-convective heat transfer of single-row horizontal bundlesof industrial bimetallic pipes with tape finning, the finning factor of 16.8. The position of the pipes in the bundle is characterized by the by transverse steps standardized for heat exchangers for air coolingS1 = 58; 61; 64; 70; 76; 86; 100 mm, to which the relative steps corresponded σ1 = S1/d = 1.208; 1.271; 1.333; 1.458; 1.583; 1.792; 2.083. An equation for calculating the free-convection heat transfer, taking into account the influence of the relative step in the range of Rayleigh number from 30,000 to 350,000 with an average deviation of ± 6.6%, has been obtained.
Model of heat and mass transfer in heated premises
Authors: Kaledin V O , Viachkina E A , Gileva A E , Viachkin E S , Galgin D A , Ulyanov A D
Published: July 2020

The heat loss model identifying inverse problem for a building through building envelopes is considered. The heat balance linear equations are used for heated rooms. These equations take into account the thermal conductivity through the walls and the glazing of the openings, two-way convective heat exchange between the room air, heating devices and enclosing structures, as well as convective heat dissipation into the environment.
Developing and modelling the invert boiler furnace for A-USC steam parameters
Authors: Prokhorov V B , Chernov S L , Kirichkov V S , Fomenko N E
Published: July 2020

Department of Thermal Power Plants of MPEI proposed the concept of a boiler of 1000 MW for advanced ultra-supercritical parameters steam generation with M-shaped profile with invert furnace and output collectors which are located under a sloping gas boiler pass. The feasibility of using ultra super supercritical parameters is associated with the possibility of increasing the unit efficiency by 4.2%. The proposed scheme of coal combustion is a system of vertical-horizontal tangential flames. For the analysis of the scheme it is offered to use physical and mathematical methods of modeling of the boiler furnace. Physical modeling allows determining the trajectories of jets and revealing their ejection capacity. Mathematical modeling is carried out using the ANSYS aerodynamics computing complex and provides an opportunity to validate and verify the results obtained on the physical model. Then with the help of the ANSYS program, the modeling of the combustion process in a full-scale version of the boiler furnace will continue. These methods are used at the Department of Thermal Power Plants of MPEI for solving problems of the organization of aerodynamics and combustion in the boiler furnaces of power boilers with traditional profiles and can be applied to research solutions for boilers of new generations.
Model of fuel spray propagation in direct injecting internal combustion engines under cross-flow conditions
Authors: Zueva T S , Garyaev A B , Weiss L
Published: July 2020

This paper is devoted to modelling of the fuel spray propagation into a cylinder of direct injecting internal combustion engines. A number of experiments were carried out to obtain data for the calculation of velocity profiles inside the spray, as well as its trajectory under cross-flow conditions. A one-hole injector was used in the experiments. The injection pressure varied from 100 till 150 bar and the air cross-flow velocities ranged from 0 till 50 m/s. The semi-empirical model was developed to describe the fuel spray propagation. The results obtained from the model and experiments were compared. The agreement of the results from experiments and the model for low velocities of the cross-flow (0-25 m/s) is significant. However, for high velocities of the cross-flow (30-50 m/s) the agreement is low. Thus, in this paper the improved model of the fuel spray propagation is proposed. A new model is based on splitting spray into parts with different densities. Each part moves with its own velocity and along its own trajectory.
Thermal conductivity of gasholders during gas storage
Authors: Nemirovsky Y V , Mozgova A S
Published: July 2020

A dynamic problem of gasholders during gas storage has been considered. Each layer of gasholders has its own physical properties, and the heat transfer coefficient depends on the coordinate system. The solution of a dynamic problem is framed using a finite integral transform technique.
Modelling grain active ventilation process in the silos
Authors: Berezina T S , Vlasenko G P
Published: July 2020

Changes in grain raw material properties in a complex thermophysical process are presented in the article, and a multifactorial mathematical model for developing engineering solutions for active ventilation is obtained. A numerical study of non-stationary changes in temperature and moisture content in a one-dimensional grain layer along with the height of a metal silo depending on environmental conditions is carried out. The simulation of the temperature and moisture fields in siloses is important for assessing the state and determining the parameters of the active ventilation system. The results show a significant air velocity effect on cooling and the speed of the drying process. The overall duration of drying and cooling of the grain top layer depends slightly on the initial parameters of the air such as the temperature and the moisture content. The obtained model is reliable to predict the drying kinetics for different storage conditions and different grain types. With the help of the presented model, it is possible to substantiate the safe grain storage modes in conditions of heterogeneity and temporal variations of standard parameters (temperature, air humidity).
Technology of Thermal Preparation of Coal for Ecologically Pure Combustion of Fuel in Small Boilers
Authors: Maysyuk E P , Kozlov A N
Published: July 2020

The problems of ecologically clean coal combustion are connected with the need to reduce the formation of pollutants to the environment during thermal transformation of fuel. Currently, about 180-190 million tons of coal are burned in Russia to produce heat and electricity, with more than 60% in the eastern regions of the country. Most of the coal (about 80%) is consumed by large thermal stations, which are equipped with pollutant trapping systems. The remaining part is burned in numerous boiler houses that operate in both urban and rural areas to provide heat to social facilities and the population. The analysis shows that the role of boiler houses increases significantly in the territories with a low population or in remote and decentralized areas. In this regard, the coal pretreatment technology before burning including the thermal preparation of coal is important. The use of thermally prepared fuel (semi-coke) will significantly reduce emissions of NOx and SOx, as well as improve the “culture” of thermal energy production at small boilers by switching to fully automated technologies, as well as significantly reducing the financial burden of utilities by reducing the wage fund and emission fees.
Special modes of diffusion mass transfer in isothermal triple gas mixtures
Authors: Kossov V N , Fedorenko O V , Mukamedenkyzy V , Kalimov A
Published: July 2020

In isothermal three-component gas mixtures in quasi-stationary conditions the procedure of numerical solution of Stefan-Maxwell diffusion equations using the software package “MathCad” is considered. It is shown that one of the specific features of multicomponent diffusion is the appearance of nonlinear concentration distributions of components in vertical channels. Due to the difference in the coefficients of mutual diffusion of gases in some systems under certain conditions, nonlinear distributions of component concentrations lead to a non-monotonic distribution of the density of the gas mixture. By the example of hydrogen – nitrogen – methane and methane – n-butane – nitrogen systems at a constant temperature T = 298 K, the influence of the content of the component with the highest molecular weight in the triple gas mixture on the degree of nonlinearity of the density distribution in the diffusion channel is analyzed. It is suggested that the inversion of the density distribution of the mixture may be the cause of convective instability in triple gas systems. The results of calculations are compared with experimental data.
Use of gasifier-based electric power stations for improving the economy of autonomous power supply systems in Russia
Authors: Marchenko O V , Solomin S V , Kozlov A N , Shamansky V A
Published: July 2020

In Russia, significant amounts of waste of logging and woodworking that can be used for energy production are generated. In this paper, we consider an autonomous power supply system, including a wood biomass gasification power plant (BGPP), a diesel power plant (DPP), one or several wind turbines (WT), and electricity consumers with their load schedule. The mathematical formulation of the problem of optimizing the structure and modes of operation of the power supply system is reduced to minimizing the objective function with a number of additional constrains. The objective function is equal to total discounted costs for the construction and operation of the system or the cost of electricity produced. Additional constrains are balances for power, primary, secondary and final energy. The power supply system was modeled for different values of diesel and wood fuels prices, average long-term wind speed, technical and economic indicators of power plants. According to the results of calculations, the zones of technologies efficiency and the cost of electricity produced are determined. It is shown that biomass gasification power plants with gas storage tanks are much more economical than diesel power plants and can displace them at current diesel fuel prices. In areas with high average annual wind speeds, biomass gasification power plants should be used in conjunction with wind turbines.
Numerical simulation of submicron particles formation during the combustion of coals, taking into account coagulation and dust content of combustion products
Authors: Kortsenshteyn N M , Petrov L V
Published: July 2020

Homogeneous-heterogeneous bulk condensation of potassium sulfate vapor has been numerically simulated in a dusty vapor-gas flow of coal combustion products upon their cooling along a technological path. A closed model that we have proposed for the formation of submicron particles in coal combustion products has been employed. Data on the concentration of particles formed at varied parameters of heterogeneous condensation sites have been obtained. Variations in the relative contributions of the homogeneous and heterogeneous mechanisms with variations in flow dustiness have been considered. Data on the influence of coagulation processes on the parameters of submicron particles resulting from coal combustion have been presented.
Physical features of fluid and structure interaction inside power unit pipeline vibration-isolating expansion joints
Authors: Kiryukhin A V , Milman O O , Sereshkin L N , Korljakova M O , Miloserdov V O
Published: July 2020

The calculation and experimental studies of vibration transmission through the pipeline compensators with liquid were carried out. No publications have been found among the scientific papers published on this issue. It has been demonstrated that the influence of structural resonances and the interaction of working medium pulsations with the structure increases vibration transmission through the compensator by two to three orders of magnitude or more with increasing frequency. The physical and mathematical models of this phenomenon are described, and a comparison of calculation and experiment is given. The ways of using the found interaction of medium pulsation and the structure to reduce vibration transmission by ten or more times within a certain frequency range are shown.
A method for calculating the aviation fuel O2 saturation process parameters
Authors: Kitanina E E , Kitanin E L , Bondarenko D A
Published: July 2020

This paper presents and substantiates the method of processing of the experimental data obtained from the experiments related to air sparging through the jet fuel layer. The experimental data was collected by Henshaw and Lam during the study addressed to oxygen re-absorption characteristics of an oxygen depleted, quiescent Jet A-1 fuel when sparged with air. In this study we accepted the hypothesis that the experimental results should be described primarily based on physical knowledge of the process and common techniques used for the description of individual components of the mass transfer process in sparging. The proposed calculation method of sparging mass transfer is valid for sparging through porous surfaces with pores of 1 μm or less, with large groups of small bubbles forming in the fuel. Moreover, the proposed method has been well-tested in the parameter range used in the underlying experiments and needs to be thoroughly checked beyond this range.
The influence of intense preliminary mechanical processing on the slag formation in coal-fired utility boilers
Authors: Chernetskiy M Yu , Butakov E B , Burdukov A P
Published: July 2020

Burdukov et al. [1] showed experimentally that enhancement of coal reactivity when micronized in a high-impact disintegrator mill makes it possible to attain self-igniting and self-sustaining (autothermal) compact-flame combustion in a cold environment. But with intensive grinding of coal, the mineral part of the fuel is also being converted, which can lead to both a decrease and an increase in the intensity of the formation of deposits. The effect of grinding on the mineral matter of coal and the formation of deposits in a 5 MW pilot-scale combustor are presented. The experiments showed a decrease in the intensity of formation of deposits after grinding of coal by disintegrating mill as compared to grinding in the ball-tube mill.
Viscosity and acoustic parameters of suspension based on ethylene glycol with aluminum nanoparticles
Authors: Pryazhnikov M I , Minakov A V , Rudyak V Ya , Platonov D V
Published: July 2020

The study of suspensions with aluminum nanoparticles was carried out. Ethylene glycol was used as the base fluid. The mass concentration of Al nanoparticles varied from 2.5 to 20%. The viscosity coefficient of the suspension at different shear rates was measured. The dependence of the viscosity on the concentration of Al nanoparticles in ethylene glycol was obtained. The attenuation of the suspensions was measured. The dependence of the sound speed in suspension on the nanoparticle concentration was obtained. The acoustic parameters of the suspension, such as adiabatic compressibility, acoustic impedance, intermolecular free length, viscous relaxation time, are calculated.
Numerical and experimental investigation of high temperature steam oxidation of molybdenum cladding specimens applied to accident tolerant fuel
Authors: Bazyuk S S , Kuzma-Kichta Yu A , Parshin N Ya , Polunin K K , Soldatkin D M
Published: July 2020

The results of high temperature steam oxidation tests of cladding specimens made of VCPM at nominal test temperature of 1200 °C and exposure duration of up to 8.5 hours at GASPAR facility are presented. The experimental data were obtained by the steam-molybdenum reaction rate constant in the range of steam mass rates from 10 to 120 mg/s and compared with the calculation results of oxidation process taking into consideration the kinetic and diffusion mechanism.
Compressibility effect on heat transfer intensified by horseshoe vortex structures in turbulent flow past a blunt-body and plate junction
Authors: Kolesnik E V , Smirnovsky A A , Smirnov E M
Published: July 2020

Results of numerical simulation of turbulent heat and mass transfer in the 3D problem of flow past a blunt-body and plate junction are presented. Comparison with the known experimental data is given; solution grid sensitivity is discussed. Numerical solutions obtained for incompressible fluid flows with different Prandtl numbers, and for the compressible gas flow with the Mach number ranging from 0.01 to 0.5 are analyzed. The effect of compressibility on heat transfer intensification in the region occupied by horseshoe-shaped vortex structures is investigated.
Experience in using a synthetic turbulence generator for eddy-resolving simulation of the free convection boundary layer on a vertical plate
Authors: Kolesnik E V , Smirnovsky A A , Tschur N A , Ivanov N G , Smirnov E M
Published: July 2020

The paper presents results of eddy-resolving numerical simulation of the turbulent free convection boundary layer that develops along a vertical isothermally heated plate. The problem of definition of boundary conditions at the computational domain inlet, where a time-varying flow field has to be specified, is considered. Mean characteristics of inflow are defined from results of RANS simulation of a 2D boundary layer, and a synthetic turbulence generator is used to introduce unsteady fluctuations at the inlet. Calculations are performed with an in-house unstructured finite-volume code; results of comparison with known experimental data are presented. The influence of the choice of the turbulence model used for RANS-based calculations of the mean inlet flow profiles is considered.
Rebound effects may jeopardize the resource savings of circular consumption: evidence from household material footprints
Authors: Ottelin Juudit , Cetinay Hale , Behrens Paul
Published: July 2020

The circular economy model aims to reduce the consumption of virgin materials by increasing the time materials remain in use while transitioning economic activities to sectors with lower material intensities. Circular economy concepts have largely been focussed on the role of businesses and institutions, yet consumer changes can have a large impact. In a more circular economy consumers often become users—they purchase access to goods and services rather than physical products. Other consumer engagement includes purchasing renewable energy, recycling and using repair and maintenance services etc. However, there are few studies on whether consumers actually make these sorts of consumption choices at large scale, and what impacts arise from these choices on life-cycle material consumption. Here we examine what types of households exhibit circular consumption habits, and whether such habits are reflected in their material footprints. We link the Eurostat Household Budget Survey 2010 with a global input-output model and assess the material footprints of 189 800 households across 24 European countries, making the results highly generalizable in the European context. Our results reveal that different types of households (young, seniors, families etc) adopt different circular features in their consumption behaviour. Furthermore, we show that due to rebound effects, the circular consumption habits investigated have a weak connection to total material footprint. Our findings highlight the limitations of circular consumption in today’s economic systems, and the need for stronger policy incentives, such as shifting taxation from renewable resources and labour to non-renewable resources.
Evaluation for p-y Method for Offshore Large Diameter Monopile in Sand
Authors: Xu Chengshun , Sun Yilong , Xi Renqiang , Sun Yanguo
Published: July 2020

Large monopile is widely used in offshore wind farm due to their relatively simple installation. Monopiles are customarily designed by applying the p-y method. That being said, there is no detailed and uniform interpretation on the reasons for limitations in the current p-y method. An elaborate study is performed to determine the main reasons of such limitations. In this study, a FLAC3D model is presented to evaluate the current p-y method for piles in sand of three different relative densities under a static load, in which the non-linear modulus is taken into account. The results show that the initial stiffness of the p-y method is overestimated and even more magnified in the large depth. The diameter effect should be taken into account under diameters exceeding 3m in loose and medium sand, as well as diameters more than 5m in dense sand.
Influence of the PTO System on the Power of Wave Energy Generator
Authors: Wan Zhanhong , Song Tianyu , Zheng Honghao
Published: July 2020

Nowadays the global demand for energy is growing rapidly, it is highly urgent to conduct the research and develop the efficient renewable wave energy equipment, wave energy converter (WEC). This paper introduces the PTO (Power Take-Off) system and theory of wave energy generators, which shows that the hydraulic system can transfer energy well. We found the relationship between the pendulum length and the wavelength of the floating pendulum wave energy generator and the relationship between the pendulum height and the wavelength. Through the influence of PTO on the power of different wave periods, the power increases first a then decreases with the increase of PTO and we also found the optimal PTO of different wave periods.
Study on the Characteristics of Tides and Storm Surge in Dongji Islands
Authors: Zhao Junyi , Zhao Xinyu , Yao Yanming , Yuan Jinxiong
Published: July 2020

Storm surge has posed a great threat to the safe development of marine ranch in Dongji Islands. Research on the tidal dynamics and storm surge of Dongji Islands is more and more urgent. For this reason, based on measured data of tidal level in 2012, this paper conducts research on the variations of tidal level and storm surge in Dongji Islands. Main conclusions are: Affected by the topography and tidal waves in the East China Sea, temporal and spatial distribution of tidal level and storm surge is asymmetric. Tidal intensity is strong in the eastern sea and weak in the western. The amplitudes of main semi-diurnal tides (M2, S2, N2) in the western sea have a significant attenuation, with the average tidal range decreased by about 16%. Cycle of the practical storm surge is consistent with the tidal constituents, for the cycle at Daishan station was close to 24 h, while Miaozihu station was about 12 h.
3-D inversion of gravity data to determine the Tulehu geothermal prospect zone, Maluku
Authors: Sulistyo A , Daud Y , Latuconsina N , Yunus F M , Kurniawan A
Published: July 2020

The Gravity method is a geophysical method that is widely used for geothermal exploration. The use of gravity data is commonly limited to interpretation of geological structure using 2-D modeling. In this study, 3-D inversion of gravity data conducted to improve 3-D conceptual model of geothermal system. This method was applied in Tulehu geothermal prospect area, which is located in Maluku Province. In 2019, gravity survey was conducted for geothermal exploration in Tulehu by gridding measurement of 130 stations with 500 m spacing. The geological condition of the area is dominated by quaternary volcanic rocks, limestone, alluvial, and metamorphic rocks. The result of CBA and residual gravity indicate the existence of medium gravity anomaly at the Mt. Eriwakang, the high gravity anomalies are found around several structures obtained from Remote Sensing. In the section of gravity 3-D inversion, it shows that the low-density contrast can be seen at 2000–3500 meter and 4500–7000 meter, while high density contrast can be seen at 0–5000 meters and 6500–8000 meters. The low and high-density contrast is associated with the presence of Huwe Fault, Banda Fault, and Banda Hatuasa Fault in the prospect area which is correlated to the geological condition. 2-D forward modeling has a good correlation to confirm the results of 3-D inversion of gravity data.
Remote sensing of tropical forest biomass: The Malaysian experiences
Authors: Hasmadi I Mohd , Pakhriazad H Z
Published: July 2020

The role of forests as potential sinks of atmospheric carbon has been studied across varying scales. In 2017, Malaysia with a total of 52 % her land is covered by tropical forest is very important not only as a source of national revenues but also as environmental protection and conservation areas. In Malaysia attempts to estimate the Above-Ground Biomass (AGB) biomass density of different forest types have been made actively as an action to meet the UN Framework Convention on Climate Change (UNFCCC). Remote sensing is a constantly evolving technology being regularly introduced where high-resolution space-borne and air-borne satellite data have provided an opportunity to better estimate and map AGB across different spatial and temporal scales. The quantification, mapping, and monitoring of biomass are now central issues due to the importance of biomass as a renewable energy source. However, the estimation of biomass is a challenging task, especially in areas with complex stands and varying environmental conditions. Remote sensing offers the technology to enable rapid assessment of biomass over large areas relatively quickly and at a low cost. This paper highlights a review of tropical forest biomass assessment techniques using remote sensing with special emphasis in Malaysia. The successful studies and key work that has been undertaken has been discussed.
Coral reefs distribution using Sentinel-2A imagery in Belanda Island, Bira Besar Island and Pramuka Island at Kepulauan Seribu National Park
Authors: Rahman T A , Supriatna S , Saraswati R
Published: July 2020

Kepulauan Seribu is known as the tourism sector, especially marine tourism and has the optimal oceanographic conditions for coral reefs suitability. Kepulauan Seribu National Park is an area as a form of conservation for coral reef ecosystems and other species with strict supervision and some restricted areas. In order to keep maintaining the conservation area, other factors such as economic and social factors are also considered by making the zone according to its location and function. Several zoning used of the area facing different problems or pressure either from natural factors or human activities. The purpose of this study was to analyze the distribution of coral reefs and the differences related to the physical characteristics of the waters in each zoning in the Kepulauan Seribu National Park using Sentinel-2A imagery. After that, data processing of research variables was carried out using bathymetry, sea surface temperature anomaly and ocean brightness data. This study found that the pattern of coral reef distribution on Belanda Island is centered on the Northeast while on Bira Besar Island and Pramuka Island are spread evenly along the reef flat. The highest percentage of coral reef distribution is found in the core zone & protection, which is equal to 6 % of all benthic habitat areas on the research island. In addition, inter-zoning has brightness and depth characteristics that vary according to geographical location.
The distribution and petrography characteristics of material eruption in the south of Rawa Danau, Banten Province
Authors: Grandis G , Indra T L , Syahputra R
Published: July 2020

Banten is an area that has geological uniqueness, particularly in Rawa Danau on the North side. The research area is a young volcanic complex surrounded by several mountains such as Mount Aseupan, Parakasak, and Karang in Serang district in Banten province. The Rawa Danau consists of swamp and lake, which is located inside an estimated Pliocene-Pleistocene caldera as the result of the ancient volcanic eruption. Based on the previous study the lithology of the lake was fine-grained fluvial sediment and swamp deposit with volcanic material. The aim of this study is to reconstruct the behaviour of the eruption in the research area and to know the area affected by the eruption using petrography analysis. The research area is dominated by pyroclastic such as breccia, tuff, and andesite in the form of lava flow and basalt that originate from M. Parakasak, M. Aseupan, and M. Karang. The mineral contents of the igneous rocks are plagioclase, pyroxene, and opaque with the microlith plagioclase as the groundmass. The degree of plagioclase extinction angle was used to differentiate between andesite rock and basalt rock. Andesite rock has more acidic plagioclase than basalt rock. The texture of andesite rock is trachytic implied that the geometry is a lava flow. The basalt rock has porphyritic texture and becomes the part of the caldera wall of Mount Parakasak.