bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical analysis of the airflow around the Gyro-One autogyro
Authors: Czyż Z , Karpiński P , Skiba K , Siadkowska K 
Published: February 2021

Abstract
The paper presents the results of numerical tests of the aerodynamics of the Gyro-One unmanned autogyro model. The geometry of the research object was developed using reverse engineering and CAD software. The created solid model of the aircraft was entered into the Ansys Meshing to generate a mesh. The boundary conditions and turbulence model were defined with Ansys Fluent software. The calculated parameters include the aerodynamic forces and the pitching moment generated on individual elements calculated with the CFD method for the selected values of the angle of attack, the velocity and pressure distributions in the plane of symmetry, and the pressure distribution on the aircraft surface for the defined measurement points. The obtained results made it possible to analyse the flow around the research object and become an introduction to further research into a hybrid multi-rotor aircraft based on the autogyro design.
Simulation of flames and smoke spreading in an underground garage under different ventilation conditions
Authors: Guz L , Grzesik M , Guz E 
Published: February 2021

Abstract
Garages are significantly endangered by the formation and spread of fire. Additionally, some building equipment or installations located in a garage such as air outlets from ventilation installation could significantly deteriorate the fire situation. To determine the influence of the AHU (Air Handling Unit) outlet inside the garage on fire spreading, a simulation was carried out using the FDS (Fire Dynamic Simulator) in the PyroSim computer software. The investigated underground garage consists of 11 separated parking bays. The following conditions of a fire source were assumed: a car with a petrol engine, a fire area - 10 m2, a range of fire - 12 m, and a total power of fire - 4 kW. The simulations were carried out for two fire scenarios: 1) normal condition (AHU is disabled), and 2) airflow from an AHU outlet (5,200 m3/h). The results show a negative effect of an AHU on fire spreading. The temperature and the concentration of smoke during fire are 2-3 times higher than if an AHU operates. In both fire scenarios, the safe temperature for humans, i.e. 60°C at a height of 2 m above the floor level has been exceeded in less than 4 minutes.
Analysis of the impact of trailing-edge wing flaps on the aerodynamic characteristics and performance of the Diamond DA-20 aircraft
Authors: Smykla I , Kopeć I , Wolski M 
Published: February 2021

Abstract
One of the factors affecting the aerodynamics and performance of aircraft profiles are flaps. The work presents the influence of selected types of flaps on Diamond DA-20 properties. The aircraft aerodynamics is described in detail. Furthermore, the three types of steady flight are presented and the ways of calculating the basic performance of the airplane are taken into consideration. The techniques used to carry out the research are discussed, the conclusions are drawn and the final results are presented. The aim of this article was to analyse the influence of trailing-edge wing flaps on the aerodynamic characteristics and performance of the Diamond DA-20 aircraft. The research focused on the aircraft in smooth configuration and with four types of trailing-edge wing flaps: pop-up, split flap, single-slotted flap and double-slotted flap in 15° and 45° positions.
CFD investigation of the main rotor for an unmanned helicopter
Authors: Królak C , Czyż Z , Siadkowska K , Kliza R 
Published: February 2021

Abstract
The paper presents the CFD analysis of the main rotor of the unmanned helicopter model with a maximum take-off mass of up to 150 kg. The calculations were performed in ANSYS Fluent software. The results of the work are the relationship between the lift force generated by the main rotor as a function of the blade angle of attack. The results are presented for the three considered rotational speeds i.e. 1400, 1600, 1800 rpm. As the angles of the blades of attack increases, an increase in the rotor lift force, torque, and power requirement of the tested main rotor was observed. Additionally, the power required to drive a carrier rotor for the three speeds in question was calculated. Examined changes in the power requirement of the main rotor also showed a percentage increase when changing the α and increasing the rotational speed. The result based on the numerical calculations for three blades main rotor model were presented in tables and diagrams.
Dependence of the heat of combustion of coals on their degree of metamorphism
Authors: Fedorova N I , Mikhaylova E S , Ismagilov Z R 
Published: February 2021

Abstract
The purpose of burning any fuel is to obtain thermal energy, the amount of which is judged by the heat of combustion, their most important thermophysical characteristic. In the modern world, the use of coal as a fuel for the production of heat and electricity leads in terms of consumption. This paper presents the results of measuring the highest heat of combustion of coal in a calorimeter unit. The analysis of the data obtained showed that the value of the highest calorific value depends on the metamorphism stage of coals and their elemental composition.
Physicochemical properties of microcomponents of the Kuznetsk Basin coals
Authors: Fedorova N I , Mikhaylova E S , Ismagilov Z R 
Published: February 2021

Abstract
Coals are heterogeneous in nature, and they most often combine different amounts of three macerals-vitrinite, liptinite and inerinite. Vitrinite, which is responsible for the caking capacity of coal, solubility in organic solvents, mechanical properties, etc., is of decisive importance for the technological properties of coal raw materials. This paper presents the results of a study of vitrinite concentrates isolated from coal of the Kuznetsk coal basin. Using chemical and physicochemical methods of analysis (technical and elemental analyses, IR and 13C NMR spectroscopy, etc.), analytical data were obtained reflecting the change in the composition of their organic mass from the degree of coalification. It was found that with an increase in the stage of metamorphism in vitrinite concentrates, the yield of volatile substances (Vdaf) decreases, the carbon content increases from 82.2 to 88.5% and, accordingly, the content of oxygen and heteroatoms in the organic mass decreases from 11.8 to 6.2%.
Study of the chemical and technological properties of long-flame, long-flame-gas and gas coals of the Kuznetsk Basin
Authors: Fedorova N I , Mikhaylova E S , Gavrilyuk O M , Ismagilov Z R 
Published: February 2021

Abstract
The results of a study of the chemical and technological properties of low-metamorphosed coals of the Kuznetsk basin of long-flame (L), long-flame-gas (LG) and gas (G) technological grades. Coal samples are low-sulfur, medium-ash with a low ash basicity index, are characterized by a rather significant yield of semi-coking resin, gaseous and volatile substances. According to the established technological indicators, these coals can be recommended for energy and technological use, for example, in the process of semi-coking.
Study of the kinetic dependences of the glow and determination of the threshold characteristics of ignition of coals with different stages of metamorphism under the action of microsecond laser pulses
Authors: Kraft Ya V , Aduev B P , Nurmukhametov D R , Ismagilov Z R 
Published: February 2021

Abstract
In this work, the study of the kinetic dependences of the glow and determination of the threshold characteristics of the ignition of coal of grades long-flame, semi-lean caking, weakly caking, lean and anthracite under the action of microsecond laser pulses was carried out. For the aforementioned coals, three successive stages of ignition were found with characteristic Hcr
thresholds. The first stage of ignition is associated with the heating of the surface of coal particles and the ignition of microprotrusions; the duration of the glow practically repeats the duration of the laser pulse. The second stage of ignition is associated with the release and ignition of volatiles in a millisecond time interval; the third-with the ignition of a non-volatile residue, the glow duration reaches 120 ms. With an increase in the degree of coalification, almost constant values of the first ignition threshold Hcr(1) are found. For the studied coals, with an increase in the degree of coalification, a decrease in the second threshold Hcr<2) and an increase in the third ignition threshold Hcr
(3)are observed.
The optimization of preparation mode of metal-carbon catalysts for oxidative desulfurization of diesel fractions
Authors: Matus E V , Efimova O S , Popova A N , Nikitin A P , Sozinov S A , Ismagilov Z R 
Published: February 2021

Abstract
To create new nanosized catalysts for oxidative transformations of sulfur compounds of thiophene series, monometallic catalysts based on carbon nanotubes M/CNTs (M = Ce, Cu, Mo) were prepared with a variation of the synthesis method. The incipient wetness impregnation method, adsorption, and precipitation methods were applied for active component introduction onto CNTs. The effect of preparation mode on textural and structural characteristics of M/CNTs was investigated using a set of physicochemical methods (optical emission spectrometry with inductively coupled plasma, low-temperature nitrogen adsorption, X-ray phase analysis, Raman spectroscopy, and scanning electron microscopy). It was shown that precipitation and impregnation methods provide appropriate metal content in catalyst composition while adsorption is suitable for synthesizing samples with a low active component concentration. The kinds of active component species are similar (CeO2, Cu2O/Cu or MoO3/MoO2) but their distribution behavior and dispersion are controlled by the preparation mode. The using precipitation method for M/CNTs synthesis provides uniform distribution of the nanosized metal-containing particles on the carbon matrix surface.
Study of the porous structure of carbon sorbents based on Kuzbass coal at various stages of metamorphism
Authors: Zykov I. Yu. , Dudnikova Y. N. , Fedorova I.N. , Ismagilov R.Z. , Mikhaylova E. S. 
Published: February 2021

Abstract
The work is devoted to the investigation of the porous structure of carbon sorbents prepared on the basis of long-flame, gas, low-caking and lean coal of Kuzbass. Carbon sorbents were obtained by alkaline activation with potassium hydroxide at 800 °C and a KOH/coal (RKOH) ratio of 0.5 g/g. Using the method of low-temperature nitrogen adsorption (analyzer ASAP-2400), the values of the textural characteristics of carbon sorbents based on coal of different stages of metamorphism were determined: pore volume, micropore volume and specific surface area. It is shown that the carbon sorbents obtained in this work are predominantly microporous (more than 80% by volume). A carbon sorbent based on long-flame coal has the greatest texture characteristics; its specific surface area is 1220 m2/g and a pore volume of 0.54 cm3/g.
Prospects for the use of steam-piston engines to increase the economic attractiveness of environmentally friendly processes for the processing of copper-molybdenum concentrates of promising deposits in Kazakhstan
Authors: Dubinin V S , Stepanova T A , Shkarupa S O , Alekseevich M Y 
Published: February 2021

Abstract
The use of old metallurgical processes is accompanied by releasing process gas into the atmosphere because its subsequent processing is not possible. New technological processes using oxygen flash smelter make it possible to obtain a sufficient concentration of sulfur oxide in process gases for sulfuric acid commercial production. A necessary element of the new type of power plants is heat recovery boilers that generate steam that can be used to generate electricity, which will increase the economic efficiency of oxygen flash smelter plants. The article shows that it is practically impossible to use steam turbines to generate electricity from this steam, and the use of steam-piston engines is proposed.
Study of the features of brown coal by pétrographie analysis
Authors: Fedorova N I , Grabovaya N A , Ismagilov Z R , Mikhaylova E S 
Published: February 2021

Abstract
The paper presents the results of petrographic analysis of five samples of brown coals from the following deposits: Itatskoye, Munayskoye, Arkharo-Boguchanskoye, Kangalasskoye, Baganuur (Mongolia). It was found that the brown coal sample from the Itatskoye deposit (Ro, r = 0.388%) has the lowest vitrinite reflectance, while the brown coal from the Kangalasskoye deposit has the highest reflectance value (Ro, r = 0.490%). An increase in the genetic maturity of the studied samples is associated with a change in the technological properties of their organic matter. It is shown that with an increase in Ro, r, the carbon content (Cdaf) increases, the yield of volatiles decreases, as well as the atomic ratio of H/C and O/C. Visual analysis of polished sections made it possible to determine the maceral composition of the studied coals. The sample of brown coal from the Baganuur deposit (Mongolia) has the highest inertinite content (more than 60%), the sample of the Kangalasskoye deposit contains the largest amount of vitrinite group macerals (86%).
Phase transformations of the nanostructured iron-platinum system upon heating
Authors: Pugachev V M , Zakharov Yu A , Popova A N , Russakov D M , Zakharov N S 
Published: February 2021

Abstract
Joint reduction with hydrazine from aqueous solutions of precursors produced nanostructured powders of the Fe – Pt system in three characteristic phase regions. The samples were subjected to heat treatment in the range up to 800 ° C and characterized at all stages by X-ray diffraction and high-resolution electron microscopy; the elemental composition of the samples was refined by the method of optical emission spectroscopy with inductively coupled plasma. In the initially obtained samples, only a part of the substance is detected by diffraction-the largest, platinum-rich crystals with dimensions of about 10 nm (established from TEM images and broadening of diffraction lines). The fcc-type cubic lattice parameters and the composition of the observed crystals were estimated from the distances between the regular bands in TEM images, identified with atomic rows, based on the composition dependence of the bulk characteristics of mixed iron-platinum phases (according to ICDD databases). In the course of heating, the processes of phase transformation are traced in detail, the parameters of the resulting crystal structures of intermetallic compounds are fixed, and the mechanisms of these transformations are discussed. Based on the measured lattice parameters, the thermal expansion coefficients of some mixed phases are calculated and the phase compositions are estimated at different stages of heat treatment.
Dimethyl ether transformations over copper chromite/alumina catalysts in the packed bed and microstructured reactors: 1. Deep oxidation
Authors: Sukhova O B , Matus E V , Ismagilov I Z , Kerzhentsev M A 
Published: February 2021

Abstract
The deep oxidation of DME in a reactor with a supported catalyst and in a microreactor has been studied. Kinetic dependences of DME oxidation were obtained and comparative results are discussed.
Modeling the propagation of air blast waves in mine workings
Authors: Mazepa E E , Kusainov P I , Krainov A Yu , Lukashov O Yu 
Published: February 2021

Abstract
The article presents a physical and mathematical model of the propagation of air shock waves in the network of coal mine workings after an instant explosion of the methane-air mixture in a given area. An approach to the implementation of a method for solving problems on the propagation of air shock waves in a branched network of mine workings is presented, taking into account arbitrary angles of their conjugation. The results of calculating the propagation of air shock waves in the model networks of mine workings are presented.
Spiral-shaped scattered field from incident evanescent acoustic waves on a Mie Particle
Authors: Alhaïtz Ludovic , Baresch Diego , Brunet Thomas , Aristégui Christophe , Poncelet Olivier 
Published: February 2021

Abstract
We consider theoretically the scattering of an incident evanescent plane wave by a spherical particle. The scattering problem is treated in a classic way by applying the T-matrix formalism and the resulting field is expressed on the basis of the different vibration modes of the particle. Compared to the case of a homogeneous plane incident wave, additional azimuthal scattered modes are excited and their contribution provokes a symmetry breaking of the field. Importantly, if a mode is preferentially excited by choosing the corresponding reduced frequency, the scattered radiation exhibits a spiral structure. The scattered field has a rotating phase around the scatterer which comes from the formation of spiral scattered waves and this effect is accentuated by increasing the evanescence degree of the incident wave. These results could have important implications for the contactless manipulation of objects with acoustic radiation forces and torques.
Measurement of the ultrasonic diffusion coefficient in a resonant multiple scattering suspension
Authors: Delmotte Fanambinana , Brunet Thomas , Clisson Gérald , Leng Jacques 
Published: February 2021

Abstract
We report on frequency-resolved experimental measurements of the ultrasonic diffusivity in the MHz range. By means of robotics, we produced a highly monodisperse suspension made of soft metallic micro-beads randomly-dispersed in a water-based gel-matrix. The measured diffusion coefficient is shown to vary significantly with frequency by more than one order of magnitude that is probably due to the sharp scattering resonances of the metallic particles.
Applications of intensive HIFU simulation based on surrogate models using the CIVA HealthCare platform
Authors: Chatillon S. , Loyet R. , Brunel L. , Chavrier F. , Guillen N. , Le Berre S. 
Published: February 2021

Abstract
High Intensity Focused Ultrasound (HIFU) uses the energy of an ultrasonic beam to cause localized heating to alter or destroy the targeted tissues. Due to its limited collateral effects, this minimally invasive therapy is, in its field of application, an alternative to surgical treatments and is rapidly expanding in terms of both clinical research and industrial development. In this context, the use of simulation is a crucial element to reduce both the development time and prototype costs, as well as the number of preclinical and clinical experiments. To this aim, CEA-LIST has been developing the simulation platform, CIVA HealthCare in partnership with INSERM for several years, which uses optimized and validated modules for the simulation of a whole HIFU therapy protocol. However, multi-parametric studies for treatment optimisation (probe design, protocol definition, etc.), sensitivity analysis, and tissue characterisation are very time-consuming, since they involve many simulations. We propose an alternative solution of replacing the computationally expensive direct solver with a surrogate model built from a database of simulation results. The procedure breaks down into two stages First, the database is adaptively constructed to maximise the fidelity of the associated interpolator computed from the pairs (Input/Output) of the database. Then in the second step, the interpolator, also called surrogate model or metamodel, enables the generation of results in near real time for configurations covered by the range of the database. This procedure and its related tools have been implemented in CIVA-HealthCare. To highlight the potential offered by such intensive HIFU simulation based on surrogate models strategy, two applications are presented: The first concerns real-time pressure field computation, and the second is based on thermal simulations and deals with sensitivity analyses according to uncertainties in tissues parameters. Work supported by French Nation Research Agency (ANR SATURN -15-CE19-0016)
Optimum design for permittivity of dielectric absorbing materials
Authors: Wu Y P , Gao X , Cheng J X , Wen W W , Wang Q B , Zhu Z M 
Published: February 2021

Abstract
In the design of absorbing materials, investigating the ideal value range of electromagnetic parameters under given conditions and adjusting the electromagnetic parameters by existing materials to achieve the ideal range need are two important issues to be solved. Based on transmission line theory and Debye theory, numerical simulations are used to explore the ideal value range of various parameters of absorbing materials under different conditions as well as their selection laws. The Cole-Cole diagram based on combining theory and experiments was given for optimizing design of absorption performance. When the thickness and reflection attenuation rate of the material are presupposed, the real and imaginary parts of the corresponding ideal permittivity should form an approximately elliptic curve. When the permittivity of the material is in the elliptical region, the reflection attenuation rate is lower than its given value. Ellipses with lower reflection attenuation locate in ellipses with higher reflection attenuation, but the centers of the ellipses do not coincide. As the reflection attenuation rate decreases, the corresponding ellipse area shrinks sharply, and the range of electromagnetic parameters becomes rigorous.
Characterization of InSb nanopillars for field emission applications
Authors: Giubileo F , Faella E , Pelella A , Grillo A , Passacantando M , LaPierre R , Goosney C , Di Bartolomeo A 
Published: February 2021

AbstractA piezoelectrically driven metallic nanoprobe is installed inside a scanning electron microscope to perform local characterization of the field emission properties of InSb nanopillars. The tip-shaped anode can be precisely positioned at sub-micron distances from the emitters to collect electrons from areas as small as 1μm2under the application of an external bias up to 100 V. Current-voltage characteristics are measured for cathode-anode separation down to 500 nm and are analyzed in the framework of the Fowler-Nordheim theory. We give estimation of performance parameters such as the field enhancement factor and the turn-on field and their dependence on the cathode-anode separation distance. We demonstrate the time stability of the emitted current for several minutes. Finally, we perform a finite element electrostatic simulation to calculate the electric field in proximity of the nanopillars and we evaluate the effective emitting area as well as the screening effect due to presence of other pillars in close vicinity. We show that InSb nanopillars are very stable emitters that allow current density as high as 104A/cm2and excellent time stability, crucial characteristics to envisage device exploitation.