bluuebunny/crossref_metadata_2025 huggingface dataset:
Corrosion Behavior of Electrodeposited Nickel Coating Reinforced by Cr2O3 Particles
Authors: Marmi Saida , Siad Shahnaz , Chala Abdelouahad , Marmi Hayat
Published: January 2021

The objective of this work is the characterisation of the composite deposits Ni-Cr2O3 on copper substrate; these deposits are obtained from bath of electro-deposition of Nickel watts. The different electrodeposited layers are characterized by various analytical techniques such as adhesion quality, corrosion tests, Vickers microhardness, morphology by scanning electron microscopy Followed by EDX microanalysis and X-ray diffraction. The corrosion tests are realized in a solution of 3.5 % NaCl using lost mass method, polarization and impedance spectroscopy techniques. It was found that the composite coatings Ni-Cr2O3 have an homogeneous and compact morphology, well crystallized and exhibit a high degree of codeposition of Cr2O3 particles incorporated in the nickel matrix. The co-deposited films have very good hardness, adhere perfectly to the substrate and are more resistant to corrosion.
A Comparative Study of Microstructure, Coefficient of Friction and Wear Rate of Alloy Ni-Cr-B-Si-C-W
Authors: Bachirbey Mohamed Nabil , Bougoffa Mohammed Seyf Eddine , Benouali Chahrazed , Sayah Tahar
Published: January 2021

The present work aims at the study of the dry disc pion contact and the complex phenomenon of the wear as well as the sliding friction of our sample elaborated by a hot isotactic compression and the pion. This study consists in determining the coefficient of friction and the influence of the tribological parameters on this phenomenon as well as determining the loss of mass and the wear rate of study sample. In order to enhance the assurance of the validity of the results of tribological study of Ni-Cr-B-Si-C-W alloy in laboratories and compare that to the tribological conditions in reality and industries. This work presents the results of the new approach to compares the wear behavior of the sample between a theoretical study (tribometer)and another in service (a test bench) that reproduces approximately the same conditions as the tribometer (normal load, sliding speed and distance traveled) by measuring the loss of mass and wear rate.
Effect of Lanthanum Substitution on Structure and Modulation in Bi2Sr2-xLaxCaCu2O8+d (0≤x≤0.3) Superconducting Compound
Authors: Mimouni Mourad , Mahboub Mohammed Sadok , Mosbah Mohammed Fayçal , Rihia Ghani , Zeroual Soria , Ghougali Mebrouk , Beggas Azzeddine
Published: January 2021

The effect of La substitution on the structure and its modulation in samples with a nominal composition of Bi2Sr2-xLaxCaCu2O8+d where 0≤x≤0.3 superconducting phase was investigated. The X-ray powder diffraction (XRPD) results showed an almost pure Bi-2212 phase, confirmed by the estimated amount of element concentration using dispersive energy X-ray spectroscopy (EDX). Scanning electron microscopy (SEM) micrographs showed a decrease of both crystallite size and connectivity when Lanthanum concentration increases. Le Bail refinement using the Jana2006 program gives a very good value of goodness of fit (GOF) factor. Also, the refinement reveals that for x=0.3 the orthorhombic cell transforms to the tetragonal one and the modulation vector q increases when increasing La concentration.
Forced Convection inside a Vertical Circular Cylinder with an Inner Coaxial Rectangular Cylinder
Authors: Boughezala Hamad Ahmed , Bouabdallah Said , Boukhari Ali
Published: January 2021

In this work, we performed a numerical simulation of laminar forced convection and, in an annular space inside a vertical circular cylinder with an inner coaxial rectangular cylinder having an aspect ratio (height/radius) γ=2, filled with a liquid metal (Pr = 0.0023). Six annular gaps R =0.9, 0.8, 0.7, 0.6, 0.5 and 0.4 were studied. The governing equations are solved using the ANSYS Fluent code which is based on the finite volume method. SIMPLE algorithm is employed for the pressure-velocity coupled momentum equations. Two cases of the rotating parts of the cylinders are investigated and the effect of Reynolds number on the flow are examined. The obtained results of the forced convection show that the increase of the Reynolds number Re affects straightly on the structure of the flow wherever the velocity field are destabilized and the strongest stabilization of the velocity field occurs when the flow generated by the rotating of the circular cylinder and the rectangular cylinder.Keywords: forced convection, annular gap, circular cylinder, rectangular cylinder, co-rotating.
Investigation of the Structural, Optical and Electrical Properties of Zinc Oxide Co-Doped with Fluorine and Cobalt
Authors: Diha Abdallah , Fellah Lahcene , Benramache Said , Belahssen Okba
Published: January 2021

Zinc oxide codoped with Fluorine and Cobalt thin films (FCZO) were successfully synthesized on heated glass substrate at 380 °C by spray pyrolysis technique. The influence of doping and codoping on the structural, optical and electrical properties were investigated. X-ray diffraction results showed that the undoped and FCZO films exhibit the hexagonal wurtzite crystal structure with a preferential orientation along [0 0 2] direction. No secondary phase is observed in FCZO films. The optical transmittance of Co doped ZnO thin films reduces up to 80 % as compared to undoped ZnO thin film in the visible region. We have observed three absorption bands at 568, 608 and 659 nm which can be attributed to the d-d transitions of tetrahedrally coordinated Co2+ ion in the high spin state. The band gap was found to be increasing in the range of 3.26-3.39 eV with Co doping whereas it decreases for higher doping of Co concentration.
Thermo-Kinetic Study of Adsorption of Methylene Blue in Aqueous Solutions Using Algerian Illite Natural and Activated Mineral Clay
Authors: Haddad Larbi , Hima Abdelkader , Dadamoussa Belkhir , Aoun Asma Messai
Published: January 2021

In this study, a local mineral clay was used as an adsorbent for the elimination of a cationic dye: methylene blue (MB), in an aqueous solution by adsorption technique. Early on, we performed mineralogical and textural analyses of a clay sample using various techniques, namely X-ray diffraction, Brunauer-Emmett-Teller analysis and Fourier-transform infrared spectroscopy. The experimental results showed that this adsorbent is a mesoporous and non-swelling clay with illite and kaolinite as the major components with a specific area of about 110m2/g. The study of MB adsorption on the clay was carried out by optimizing the conditions of adsorption, notably the initial concentration of pollutant C0, the mass of clay m, the contact time t, the potential of hydrogen of the solution pH and the temperature T. Experimental results have shown that the equilibrium data are well adjusted by a Langmuir isotherm equation. Thermodynamic parameters such as the changes in Gibbs free energy, enthalpy, and entropy were determined from batch experiments. Results revealed that the adsorption of MB onto illitic clay was endothermic and spontaneous process. Kinetic modeling was also carried out. Experimental data adjusted the kinetic model of pseudo-second order with two stages of intraparticle diffusion.
Effects of Important Parameters on the Transition from Forced to Mixed Convection Flow in a Square Cavity
Authors: Boulkroune Sofiane , Kholai Omar , Mahfoud Brahim
Published: January 2021

Combined free and forced convection in a square cavity filled with a viscous fluid characterized by a small Prandtl number is studied numerically. The left wall is moving with a constant velocity v and is maintained at a local cold temperature Tc, while the right wall is fixed and maintained at a local hot temperature Th (Tc <Th). The top and bottom walls of the cavity is assumed to be adiabatic. The governing Navier-Stokes, and energy equations along with appropriate boundary conditions are solved using the finite-volume method. The flow and temperature fields are presented by stream function and isotherms, respectively. The effects of important parameters such as Reynolds number, Prandtl number, and Grashof number on the transition from forced convection to mixed convection are investigated. Results indicate that increasing Reynolds number results to fluid acceleration and, thus, to flow transition. Results also show that Grashof and Prandtl's numbers influenced the conditions for the transition to the mixed convection regime.
Effect of Rolling Deformation on Corrosion Behaviour of AISI 304L in 3% NaCl Solution
Authors: Yahia Lazhar , Nouicer Elamine , Benlahreche Fatima Zohra
Published: January 2021

It is well known that the mechanical resistance of austenitic stainless steels can be increased considerably by cold rolling process.¶ The cold rolling effect on corrosion resistance of AISI 304L stainless steel in 3% Sodium Chloride solution was investigated by potentiodynamic polarisation and by Scanning Electronic Microscopy (SEM). The pitting corrosion in this environment is related to the rate of cold deformation. The cold rolling induces important changes in the microstructure and involves phase transformation (γ→a'). The AISI 304L developes martensitic structure after 16% cold working. The potentiodynamic results show a moderate variation of the passivity zone, a remarkable decrease in the pitting potential and a free potential. The results also show an increase in the current density. However, it seems that the critical deformation rate appears to start at approximately 50% of the rolling deformation where the passivation current is minimal. After the polarisation tests, metastable pits are observed using SEM and the most probable initiation causes are discussed
Electrochemical and Theoretical Studies of Inula viscosa Extract as Green Corrosion Inhibitor for Mild Steel in Hydrochloric Acid Solution
Authors: Elhassasna Souhir , Brahim Harkati , Samah Hadjar
Published: January 2021

In this employ, we deliberate the effectuality of corroding inhibition of carbon steel API 5 L Gr – B in HCl 1M solution using the n-butanolic extract taken of Inula Viscosa plant. The repressive strength was observed by the electrochemical methods, Videlicet potentiodynamic condition and impedance measurements. The results indicated that the forbiddance efficiency increases with exploding choose attention. A maximum inhibition rate of 92.37 % was recorded at 600 ppm of inhibitor denseness according to the potentiodynamic measurements. The extract seems to be a goodness corroding inhibitor of electrode writing based on the obtained results. The adsorption on the element articulator was instituted to obey to Langmuir isotherm. In expansion, the HOMO and LUMO analyzing were carried out utilizing the useful thickness hypothesis strategy (DFT / B3LYP). Since HOMO and LUMO are the foremost critical orbitals in atoms, they are exceptionally valuable for understanding certain atomic properties. In expansion, from the outcome of the DFT calculations, we obtained as follows: the total dipole moment of the molecule (μ), the absolute hardness (η), the absolute electronic negativity (χ).
Tamanrasset’s Clay Characterization and Use as Low Cost, Ecofriendly and Sustainable Material for Water Treatment: Progress and Challenge in Copper Cu (II)
Authors: Kourim Aicha , Malouki Moulay Abderrahmane , Ziouche Aicha , Boulahbal Mouna , Mokhtari Madjda
Published: January 2021

In this study, the adsorption of copper Cu (II) from aqueous solution, on Tamanrasset’s clay which is low cost adsorbent, was studied using batch experiments. The adsorption study includes both equilibrium adsorption isotherms and kinetics. The characterization of the adsorbent necessitated several methods such as X-Ray Diffraction, Scanning Electron Microscopy coupled with Energy Dispersive X-ray, BET for specific surface area determination, Fourier transform infrared spectroscopy and thermogravimetric analysis. Indeed, various parameters were investigated such as contact time, initial metal ion concentration, mass of solid, pH of the solution and temperature. The adsorption process as batch study was investigated under the previews experimental parameters. The results revealed that the adsorption capacity of Cu2+is maximized at naturel pH of metal 5.5. Removal of copper by the clay of Tamanrasset (kaolinite) achieved equilibrium within 50 minutes; the results obtained were found to be fitted by the pseudo-second order kinetics model. The equilibrium process was well described by the Langmuir model and the maximum adsorption capacity was found to be 26.59 mg/g.
Application of Associated and Non-Associated Flow Metal Plasticity for F.S.S Sheet
Authors: Chahaoui Oualid , Soltani Houssem , Matougui Nadjoua
Published: January 2021

In the last decade, several phenomenological yield criteria for anisotropic material has been proposed to improve the modeling predictions about sheet metal-forming processes. In regard to this engineering application, two proprieties of models have been used. If the yield function and the plastic potential are not same (not equal), the normality rule is non associative flow rule (NAFR), otherwise, when the stresses yield has been completely coupled to the anisotropic strain rate ratio (plastic potential), is called the associated flow rule (AFR). The non-associated flow rule is largely adopted to predict a plastic behavior for metal forming, accurately about à strong mechanical anisotropy presents in sheet metal forming processes. However, various studies described the limits of the AFR concept in dealing with highly anisotropic materials. In this study, the quadratic Hill1948 yield criteria is considered to predict mechanical behavior under AFR and NAFR approach. Experiment and modeling predictions behaviour of normalized anisotropic coefficient r (θ) and σ (θ) evolved with θ in sheet plane. and the equibiaxial yield stress σb was assumed σb=1 but the rb-values was computed from Yld96 [15].
Wire Drawing Effect on Microstructural and Textural Evolution in Medium Carbon Steel Wires
Authors: Nebbar Mohamed Chaouki , Zidani Mosbah , Messaoudi Salim , Abid Taher , Kisrane-Bouzidi Ahmed , Baudin Thierry
Published: January 2021

This study was mainly oriented on the evolution of the crystallographic texture as a function of the deformation resulting from the industrial wire drawing process. This, in fact, will make it possible to establish a relationship between the microstructure and the crystallographic texture in the medium carbon steel wires obtained by industrial wire drawing process and used in the manufacture of spring mattresses in order to minimize the loss of material and to satisfy the users of this product.During this study, a medium-carbon steel wires was characterized by two analytical techniques. The scanning electron microscopy (SEM) to monitor the microstructure evolution and the electron backscatter diffraction (EBSD) for the crystallographic texture analysis. The EBSD results are processed with OIM (Orientation Imaging Microscopy) analysis software.
Heat Transfer Mode and Effect of Fluid Flow on the Morphology of the Weld Pool
Authors: Zitouni Abdel Halim , Spiteri Pierre , Aissani Mouloud , Benkheda Younes
Published: January 2021

In this work, the heat transfer by conduction and convection mode and effect of fluid flow on the morphology of the weld pool and the welding properties is investigated during Tungsten Inert Gas (TIG) process. In the first part, a computation code under Fortran was elaborated to solve the equations resulting from the finite difference discretization of the heat equation, taking into account the liquid-solid phase change with the associated boundary conditions. In order to calculate the velocity field during welding, the Navier-Stokes equations in the melt zone were simplified and solved considering their stream-vorticity formulation. A mathematical model was developed to study the effect of the melted liquid movement on the weld pool. The evolution of the fraction volume of the liquid and the thermal fields promoted the determination of the molten zone (MZ) and the Heat Affected Zone (HAT) dimensions, which seems to be in good agreement with literature.
Prandtl and Richardson Number Effects on Mixed Convection in a Vented Enclosure on Application to the Cooling of the Fins
Authors: Chaour Mohamed , Boudebous Saadoun
Published: January 2021

In the present study, a numerical investigate the transport mechanism of laminar mixed convection in a vented enclosure. The walls of the cavity were kept adiabatic except the right vertical wall which was equipped with three fins dissipating the heat at a constant temperature. The equations of considered phenomenon were established and discretized by the finite difference method. The sweeping method line-by-line and the Thomas Algorithm (TDMA) were used for the resolution of the system of discretized equations. The results obtained showed that both the variations of the Prandtl and Richardson number have important effects on the flow structure and on the heat transfer.
Heat and Mass Transfer in an Inclined Bi-L-Shaped Layered Porous Media: Effect of Buoyancy Ration
Authors: Abdelkrim Latreche , Mahfoud Djezzar
Published: January 2021

The effect of buoyancy ratio on the two dimensional natural convection heat and mass transfer generated in an inclined square bi-L-shaped layered porous cavity filled with Newtonian fluid has been investigated numerically. Each porous layer is considered isotropic, homogeneous and saturated with the same fluid. The cavity is heated and salted from below where as the vertical walls are assumed to be adiabatic and impermeable. The physical model for the momentum conservation equation makes use of the Darcy-Brinkman-Forcheimer model, and the set of coupled equations is solved using a finite volume approach. The power-law scheme is used to evaluate the flow, heat and mass fluxes across each of the control volume boundaries. Tri diagonal matrix algorithm with under-relaxation is used in conjunction with iterations to solve the nonlinear discretized equations. An in-house code developed for this study is validated using previous studies. The results are presented graphically in terms of streamlines, isotherms and iso-concentrations. In addition, the heat and mass transfer rate in the cavity is measured in terms of the average Nusselt and Sherwood numbers.
Numerical Simulation of Boundary Conditions Effect on Heat Transfer and Entropy Generation in a Square Cavity Filled with Al2O3-Cu -Water Hybrid Nanofluid
Authors: Zeghbid Ilhem , Bessaih Rachid
Published: January 2021

A numerical simulation was performed in four geometries with different boundary conditions; two geometries have top walls moving with a constant horizontal velocity U0 in two opposite directions, while the other geometries have vertical walls moving in two opposite directions with a constant vertical velocity V0. These cavities are filled with hybrid nanofluid Al2O3-Cu/water, and heated by two constant flow heat sources placed on the left vertical wall. The moving wall and the other walls are respectively maintained at a local cold temperature Tc. The interest of this work is to see the effects generated by incorporation of hybrid nanofluids on the mixed convection flow, and to make an analysis of the entropy production in the mixed convection problem in order to be able to choose the geometry with different boundary conditions among the four geometries with different boundary conditions that will ensure energy efficiency. The finite volume method was used to solve the heat transfer flow equations across the physical domain with the SIMPLER algorithm. The influence of relevant parameters such as Richardson and Reynolds numbers and volume fraction of nanoparticles on entropy generation and heat transfer rate were studied. It was found that entropy generation decreases with increasing Richardson number, Reynolds number and that incorporation of a hybrid Al2O3-Cu/water nanofluid in the base fluid improves the high heat transfer rate.
Transient Heat Analysis in a Two-Step Radiative Combustible Slab
Authors: Lebelo Ramoshweu Solomon , Moloi Kholeka Constance
Published: January 2021

In this article, analysis of heat transfer in a stockpile of reactive materials modelled in a rectangular slab is carried out. A two-step exothermic chemical reaction is assumed and the heat loss to the surrounding environment is by radiation. The ordinary differential equation (ODE) governing the problem is tackled numerically by Runge-Kutta Fehlberg (RKF45) method coupled with Shooting technique. The heat transfer analysis is simplified by investigation some kinetic parameters’ effects on the temperature of the combusting system. It was found out that some kinetic parameters raise the levels of the temperature by encouraging the exothermic chemical reaction, whereas some, reduce the levels of the temperature to slow down the heat transfer rate. The results are depicted graphically and discussed accordingly.
Na2O Promotion on CO2 Hydrogenation on the χ-Fe5C2(2 0 0) Surface
Authors: Qu Ya Kun , Zhao Xiao Guang , Wang Li Xin , Wu Yu
Published: January 2021

Understanding the origin of the high activity of Na2O promotion on the χ-Fe5C2(2 0 0) surface during CO2 hydrogenation is imperative. In this work, we revealed how Na2O promoted the catalytic performance of χ-Fe5C2 during CO2 hydrogenation. Detailed analyses confirmed that Na2O addition facilitated the adsorption of CO2 and promoted the desorption of product (C2H4). Electronic structure calculations suggested that the electron donating ability of Na could enhance the dissociation of CO2, which is essential for producing hydrocarbons from CO2.
Specifics of Structure Formation of Cement Stone with Silica Raw Material - A Substrate of Photocatalytic Composite Material
Authors: Nelyubova Viktoriya V. , Ogurtsova Yulia N. , Sivalneva M.N. , Strokova Valeria V. , Zhao P.
Published: January 2021

The increasing urbanization of urban areas poses the challenge of the development of materials capable of self-cleaning from organic pollutants formed. Previous papers substantiated the possibility of the coating of titanium oxide as the main agent of the photocatalytic method of cleaning structural materials on silica raw materials in order to increase the degree of its distribution in the volume of cement matrix and, as a result, increase its efficiency.It is obvious that a silica substrate will affect the processes of structure formation during hardening of a cement matrix. During the research, the processes of phase transformations of cement stone modified with silica raw materials of natural and technogenic origin were studied. As a result, the influence of siliceous modifiers on the strength characteristics of the cement stone was determined, which allowed ranking them according to the degree of decrease in efficiency as follows: technogenic raw materials; natural raw materials of silicate composition; natural raw materials of aluminosilicate composition. Quantitative assessments of the degree of efficiency showed the irrationality of using aluminosilicate composition as a silica modifier of natural raw materials, which is explained by its low pozzolanic activity.
Мineral Powders Dispersion Degree Effect on the Properties of the Cementing Alkaline System
Authors: Murtazaev Said Alvi , Mintsaev Magomed , Salamanova Madina , Aymenov Zhambui , Alaskhanov Arbi
Published: January 2021

This paper presents the results of studies on mineral powders dispersion degree effect on the properties of alkaline cement-water paste where powders are of natural and technogenic origin. The change dependences between the total specific surface area and the duration of grinding have been studied, and the optimal grinding time for raw materials has been revealed. The developed formulations of cementing alkaline binders, with the use of mineral powders and wastes from the cement industry, are distinguished by short setting times and high consumption of alkaline grout to obtain a cement paste of normal density, which requires further research. And the obtained influence patterns of the degree of dispersion on the properties of the "mineral powder - Na2SiO3" binder will make it possible to create strong and durable artificial building composites competing with concretes based on Portland cement. The results presented in this article were obtained within the framework of studies on the implementation of scientific project No. 05. 607.21.0320. "Development of technology for new building composites based on clinkerless cement of alkaline activation using substandard natural and secondary raw materials" supported by the Federal Target Program "Research and Development in Priority Areas of Development of the Scientific and Technological Complex of Russia for 2014-2020". The unique identifier for the agreement is RFMTFI60719X0320.
Effect of Mixing Procedure and Chemical Composition on Physical and Mechanical Performance of Geopolymers
Authors: Kozhukhova Natalia I. , Teslya Anastasia Yu. , Alfimova Natalia I. , Kozhukhova Marina I.
Published: January 2021

Nowadays geopolymer is promising and relevant material that can be effectively used in wide range of application areas. It is possible because of there are a lot of potential sources of raw materials for geopolymer synthesis. Raw components are the one of the key parameters that effect on geopolymer performance. On the other hands, the technological stages of geopolymer synthesis is no less important factor. The purpose of this study was to determine effect of technological parameters of geopolymer synthesis such as component composition of solid state phase, alkaline activator preparation and its introduction onto geopolymer paste as well as curing temperature on performance characteristics of geopolymer. Fly-ash based geopolymer samples were prepared with adding of different mineral components: Portland cement (PC), kaolin, metakaolin; different curing temperature conditions: ambient temperature and temperature treatment at 70 °C in oven during 24 hours; different methods of preparation and application of alkaline activator: using of fresh alkaline solution and using alkaline solution after 24 hours of cooling. The results show that efficiency of curing temperature conditions strongly depend on component composition of geopolymer paste. Samples, containing PC and metakaolin demonstrate better characteristics after curing under ambient temperature. Samples, containing kaolin and reference composition (fly ash only) the temperature treatment in oven is the best curing method (increasing in compressive strength up to 13 times). Using alkaline solution of NaOH after 24 hours of cooling gives a good effect on geopolymerization process and provides increasing in compressive strength value from 13 to 84 % for all experimental geopolymer pastes. However, average density for all compositions is varied slightly.
Microstructural Analysis of Changes in the Morphology of Quartz Raw Materials of Different Genesis at Dry Milling
Authors: Fomina Ekaterina V. , Kozhukhova Natalia I. , Belovodsky Evgeny A. , Klimenko V.A. , Kozhukhova Marina I.
Published: January 2021

The influence of the genesis of quartz-containing rocks on the strength of particles and changes in morphology during destruction from the standpoint of the mineralogical approach in the development of the scientific direction "geonics" ("geomimetics") has been investigated. The kinetics of dry grinding of raw materials in a laboratory ball roller mill was carried out. The features of the formation and development of cracks, particle size distribution, changes in the morphology and microstructure of fragments have been studied. It was found that in natural quartz cracks develop along the surface, where the highest concentration of impurities creates a defect structure with destruction into small particles. The purest structure of hydrothermal quartz is susceptible to brittle fracture into fragments similar in morphology to the base particle. Reducing the defectiveness of the structure increases the strength of the crystals. The internal energy potential of techno genic raw materials is determined by its defective structure, which undergoes the greatest deformations during grinding, allowing obtaining the maximum values of the specific surface area and reduce the grinding time. A difference in the degree of crystallinity of quartz, which composes the polymineral techno genic raw materials, makes it possible to obtain the optimal granulometry of fine particles. The conducted research is aimed at identifying the mechanisms of destruction of quartz rocks and can be used in solving engineering problems not only in construction materials science, but also in geotechnics.
Modeling the Conditions for Microdroplets Formation and their Detachment from the Molten Metal on the Electrode
Authors: Sarychev V.D. , Solodsky S.A. , Nevskii Sergey A. , Kuznetsov M.A. , Ilyaschenko D.P. , Zernin E.A. , Korepina N.A.
Published: January 2021

Formation of nanostructure states on the surface of materials exposed to concentrated flows of energy is one of the relevant problems of modern materials processing. In the paper the authors describe the mechanism of the micro-scale droplets formation based on the study and modeling of the physical processes and technological aspects of the interaction between the heterogenic plasma flows and the molten substance at the electrode tip. The authors show new physical mechanisms and criteria for micro-and nanoparticles origination, develop a physical-mathematical model of the interaction between the molten metal and the plasma discharge with imposed high-frequency pulse action.
Laser Welding of Stainless Steel 321 in Different Welding Positions
Authors: Bernatskyi A. , Berdnikova Olena M. , Sydorets V. , Kostin Valery , Kushnarova Olha
Published: January 2021

It was revealed that spatial position during laser welding of AISI 321 stainless steel influences the processes in the weld pool and the process of its crystallization. The geometry, structure, distribution of chemical elements depend on the cooling rate of the welded joint, which varies in different spatial positions during laser welding of stainless steel AISI 321. To achieve the lowest variance of results and the maximum values of mechanical characteristics of the welded joints of AISI 321 stainless steel it is recommended to produce laser welding in a vertical position.
Investigation of Influence of Input Energy during Ball Milling of Aluminum Powder
Authors: Klinkov S.V. , Kosarev V.F. , Chesnokov A.E. , Smirnov A.V. , Vidyuk T.M.
Published: January 2021

Influence of the rate at which energy is applied to aluminum powder during its ball milling is investigated. Rolling granulation is a main process due to which treated particles achieve their unique morphology and microstructure. Drastic temperature rise at rapid ball milling leads to increase in plasticity and local melting of treated powder particles that result in their adherence to the surfaces of milling balls and mill cylinder walls. Mass of aluminum powder adhered to the ball surface is proportional to the total surface area of all balls loaded in mill.
Development of a Technique for the Study of the Coated Abrasive Surface Wear
Authors: Lyukshin V.S. , Shatko Dmitry B. , Strelnikov P.A.
Published: January 2021

Wear of abrasive tools, including coated abrasives, is an important performance feature. A large number of theoretical works and practical studies are devoted to wear assessment issues. In practice, there are many direct and indirect approaches to measuring wear of an abrasive tool. At the same time, many of them have significant shortcomings such as assessment complexity, high time costs, a significant share of manual labor, low measurement accuracy, the need to use specialized equipment, etc. Based on the foregoing, the development of an effective technique for assessing the coated abrasive wear with the use of information and analytical technologies is very relevant and promising. This work is devoted to the development of an original technique for determining the wear of coated abrasives and studying of the tool surface texture. Some results of studies on the wear of coated abrasives of various grain sizes and manufacturers are presented in the article.
Structure and Properties of High-Strength Titanium Alloy Ti-6.5Al-3Mo-2.5V-4Nb-1Cr-1Fe-2.5Zr Welded Joints
Authors: Akhonin S.V. , Belous V.Yu. , Selin R.V. , Berezos V.A.
Published: January 2021

As intensive work is underway in leading material science centers in the USA, EU, Russia, and China, both to modernize existing titanium alloys and to create new ones, the E.O. Paton Electric Welding Institute of the National Academy of Sciences of Ukraine developed titanium alloys T110 (Ti-5.5Al-1.2Mo-1.2V-4Nb-2Fe-0.5Zr system) and T120 (Ti-6.5Al-3Mo-2.5V-4Nb-1Cr-1Fe-2.5Zr system), which according to their characteristics, belong to the group of modern two-phase high-alloyed alloys characterized by high strength and good ductility. With more and more attention is being paid to the expansion in the usage of welded structures and assemblies of high strength titanium alloys with UTS ≥ 1100 MPa, there’s urgent need in studying best ways to obtain welded joints from such alloys. The weldability of two-phase high-alloyed titanium alloys, the use of which can give big reduction in structural weight, is significantly worse than low-alloyed alloys, therefore for a new alloy it is necessary to ensure the possibility of obtaining welded joints with a strength of at least 90% compared to the strength of base material. The aim of this work is to study the influence of the welding thermal cycle and reducing of weld metal alloying degree on the structure and mechanical properties of welded joints of high-strength titanium alloy Ti-6.5Al-3Mo-2.5V-4Nb-1Cr-1Fe-2.5Zr with tensile strength more than 1200 MPa, as well as assessment of it welded joints properties in comparison with other high-strength titanium alloys.
Overwintering behaviour of the skipper fly (Diptera: Piophilidae) of forensic importance in Québec, Canada
Authors: Maisonhaute Julie-Éléonore , Forbes Shari L.
Published: January 2021

Laboratory experiments and field observations from August 2019 to April 2020 demonstrated that skipper flies (Diptera: Piophilidae) overwinter as larvae and likely present an obligatory winter diapause in Québec, Canada. Diapause was confirmed by the very few emergences of adults in the laboratory following collection from carrion at the end of summer and in fall, the migration of larvae deep in the soil, and the persistence of larvae inside carrion during the winter until the following spring when they became active again and initiated pupation (i.e., intra-puparial period). To our knowledge, our observations represent the first report of the overwintering of skipper fly larvae inside an animal carcass in North America. In addition, this winter diapause should be considered in forensic entomology when using the presence of skipper fly larvae on a body to estimate the time elapsed since death.
Hyperglycemic Memory of Innate Immune Cells Promotes In Vitro Proinflammatory Responses of Human Monocytes and Murine Macrophages
Authors: Thiem Kathrin , Keating Samuel T. , Netea Mihai G. , Riksen Niels P. , Tack Cees J. , van Diepen Janna , Stienstra Rinke
Published: January 2021

It has been well established that the presence of diabetes is accompanied by a chronic inflammatory state promoting various diabetes-associated complications. One potential driver of this enhanced inflammatory state in patients with diabetes is hyperglycemia. Even after blood glucose control is achieved, diabetes-associated complications persist, suggesting the presence of a “hyperglycemic memory.” Innate immune cells, critically involved in various complications associated with diabetes, can build nonspecific, immunological memory (trained immunity) via epigenetic regulation. We examine the potential involvement of hyperglycemia-induced trained immunity in promoting inflammation. Our results show that hyperglycemia induces a trained phenotype in vivo in mice and in vitro in human monocytes, representative by an increased TNF-α secretion after ex vivo stimulation with LPS. These effects were largely mediated by epigenetic changes controlled by the mixed lineage leukemia (MLL) family because treatment with the MLL inhibitor menin-MLL during the process of trained immunity acquisition repressed the proinflammatory phenotype. Collectively, our results identify a novel link between hyperglycemia and inflammation in innate immune cells that might explain the increased proinflammatory state during diabetes potentially contributing to the development of various diabetes-associated complications.
Diffuse idiopathic skeletal hyperostosis: a review
Authors: Mader Reuven , Marotto Daniela , Batticciotto Alberto , Filippou Georgios , Bieber Amir , Novofastovski Irina , Giorgi Valeria , Carotti Marina , Salaffi Fausto , Sarzi Puttini Piercarlo
Published: January 2021

Coined in 1975 by Resnick et al., diffuse idiopathic skeletal hyperostosis describes a systemic condition that is mainly characterized by flowing ossification of the spine and, less frequently, peripheral entheses. Its overall incidence is 6-12%, but it is more frequently observed in males than in females and subjects aged >50 years, and its increased prevalence in people aged >70 years suggests that the course of the disease begins between the third and fifth decade of life but its clinical manifestations do not appear until later. Its pathogenesis and etiology remain unknown, but it has been reported to be associated with a number of genetic, metabolic, and constitutional factors. The aim of this review is to describe the main features of the disease and stimulate research into its pathogenesis, prevention, and treatment.
Spatial and spatiotemporal dynamics of visceral leishmaniasis in an endemic North-eastern region of Brazil
Authors: Almeida Ândria Silveira , Ribeiro Caíque Jordan Nunes , Carlini Camila Caroline , Santos Rogério Silva , Dos Santos Allan Dantas , Tavares Débora Santos , De Araújo Karina Conceição Gomes Machado , Moura Tatiana Rodrigues de , Santos Priscila Lima dos
Published: January 2021

Visceral Leishmaniasis (VL) is a neglected disease with increasing incidence in Brazil, particularly in the North-eastern. The aim of this study was to analyze the spatial and spatiotemporal dynamics of VL in an endemic region of North-eastern Brazil, between 2009 and 2017. Using spatial analysis techniques, an ecological and time series study was made regarding VL cases in Sergipe filed as notifiable disease events. With data from the Brazilian Institute of Geography and Statistics (Instituto Brasileiro de Geografia e Estatística, IBGE), a digital population and cartographic baseline was established. Segmented linear regression was used to examine the temporal trends. The statistical analysis methods of Global and Local Moran’ I, local Bayesian empirical methodology and spatial-temporal scanning were used to produce thematic maps. High instances were found among adults, males, urban residents, non-Whites and persons with low levels of education. A decrease in the recovery rate and an increase in the proportion of urban cases and lethality was found. A heterogeneous VL distribution with spatiotemporal agglomeration on the seaside of the state was seen in Sergipe. To better manage the disease, new research is encouraged together with development of public health strategies. Further, improving health care networks, especially primary care, is suggested as this approach has a key role in health promotion, prevention and monitoring of the most prevalent diseases.
Knowledge Translation in Athletic Training: Considerations for Bridging the Knowledge-to-Practice Gap
Authors: Welch Bacon Cailee E. , Pike Lacy Alicia M. , Lam Kenneth C.
Published: January 2021

As the athletic training profession continues to embrace evidence-based practice, athletic trainers should not only critically appraise the best available evidence but also effectively translate it into clinical practice to optimize patient outcomes. Whereas previous authors investigated the effectiveness of educational interventions on increasing knowledge of critical appraisal of evidence, little attention has been given to strategies for both researchers and clinicians to effectively translate evidence into clinical practice. The use of knowledge translation strategies has the potential to bridge the knowledge-to-practice gap, which could lead to reduced health costs, improved patient outcomes, and enhanced quality of care. The purpose of this article is to (1) highlight the current challenges preventing the successful translation of evidence into practice, (2) discuss knowledge translation and describe the conceptual frameworks behind the effective translation of evidence into practice, and (3) identify considerations for athletic trainers as they continue to provide high-quality patient care in an evidence-based manner.
An observational study on safety and
efficacy of povidone-iodine for pleurodesis in
cancer patients
Authors: Makkar Ayush , Patni Sanjeev , Joad Anjum Khan , Lakhera Kamal Kishor
Published: January 2021

Introduction: Pleurodesis is a
time-honored procedure for malignant effusion as
one of the palliative procedures to treat
recurrent effusions. Various agents have been used
in the past such as tetracycline, talc, bleomycin,
and povidone-iodine. This paper aims at evaluating
safety and efficacy of povidone-iodine for the
procedure. Materials and Methods: One hundred and
four patients underwent of pleurodesis with
povidone-iodine done at our center for malignant
effusion between June 2008 and August 2015. The
safety and efficacy of the procedure was analyzed.
Results: One hundred and four patients of
malignant effusion with mean age of 53 years and a
mean follow-up of 7.8 months were evaluated. A
total of 79% patients did not show any
reaccumulation of fluid in their follow-up. There
was no periprocedural mortality. Eight patients
had severe pain; eleven patients had fever, while
one patient had arrhythmia.Conclusion:
Povidone-iodine is a simple, cheap, and effective
method of pleurodesis with no major complication
and a high success rate.
Impact and prognostic value of
18F-fluorodeoxyglucose positron emission
tomography-computed tomography scan in the
evaluation of residual head and neck cancer:
Single-center experience from Pakistan
Authors: Riaz Saima , Bashir Humayun , Iqbal Hassan , Jamshed Arif , Murtaza Ahmad , Hussain Raza
Published: January 2021

Background: Overview of clinical impact
of positron emission tomography-computed
tomography (PET-CT) scans in patients with head
and neck carcinomas at our center. Methods:
Retrospective review of posttreatment
18F-fluorodeoxyglucose (18F-FDG) PET-CT scans in
patients with head and neck carcinomas with risk
of residual disease. Clinical outcome served as
the reference standard. Results: This study
included 93 patients (65.6% males, mean age: 48.8
years ± 17.2 standard deviation) with squamous
cell carcinoma as most frequent histopathology
(91.4%). PET-CT scans were performed on average 6
months posttreatment. Diagnostic accuracy,
positive predictive value, and negative predictive
value of PET-CT for disease were found to be 88%,
88%, and 92%, respectively. A median follow-up of
24 months was available for 91 patients.
Kaplan–Meier curves showed significantly higher
disease-free survival with negative PET-CT as
compared to positive PET-CT (P = 0.01) and maximum
standardized uptake values of <5.0 (P = 0.01).
Conclusion: FDG PET-CT has diagnostic and
prognostic implications in treated patient of head
and neck cancers.
The impact of irradiation dose on the
computed tomography radiographic response of
metastatic nodes and clinical outcomes in cervix
cancer in a low-resource setting
Authors: McKeever Matthew Ryan , Hwang Lindsay , Barclay Jennifer , Xi Yin , Bailey April , Albuquerque Kevin
Published: January 2021

Introduction: The aim of this study is to
investigate the relationship between the radiation
dose to pelvic and para-aortic lymph nodes, nodal
response, and clinical outcomes in a resource-poor
setting based on computed tomography (CT) nodal
size alone. Materials and Methods: This
retrospective study from 2009 to 2015 included 46
cervical cancer patients with 133 metastatic
pelvic and para-aortic lymph nodes definitively
treated with chemoradiation and brachytherapy in a
public hospital with limited access to positron
emission tomography (PET) scans. Hence, short axis
of the lymph node on CT scan was used as a measure
of metastatic nodal disease, before and following
radiation therapy. Inclusion criteria required the
pelvic and para-aortic nodes to have the shortest
axis diameter on CT scan of ≥8 mm and ≥10 mm,
respectively. Based on PET resolution, a node that
decreased to half of its inclusion cutoff size was
considered to have a complete response (CR).
Relevant clinical outcomes were documented and
correlated with nodal features, nodal radiation
doses, and treatment characteristics. Results:
After controlling for other predictive factors,
increased nodal dose was associated with increased
probability of CR per study definition (P =
0.005). However, there was no statistically
significant association between dose and
pelvic/para-aortic, distant and total recurrence
(TR), and any recurrence at any location (P =
0.263, 0.785, 1.00, respectively). Patients who
had no CR nodes had shorter pelvic/para-aortic
recurrence-free survival (PPRFS) and TR-free
survival (TRFS) than patients who had at least one
CR node (P = 0.027 and 0.046, respectively).
Patients with no CR nodes also had shorter PPRFS
than patients who had all nodes completely respond
(P < 0.05). Conclusions: Using CT-based
measures, we found that increased nodal dose is
associated with an increased probability of CR (as
defined) and nodal CR is associated with increased
PPRFS and TRFS. We were unable to determine the
cutoff dose required for a CR.
Evaluating the Role of HLA DRB1 Alleles and Oligoclonal Bands in Influencing Clinical Course of Multiple Sclerosis – A Study from the Mangalore Demyelinating Disease Registry
Authors: DCunha Anitha , Pandit Lekha , Malli Chaithra , Sudhir Akshatha
Published: January 2021

Background:

The possible interaction between genetic and immunological factors in influencing clinical course of multiple sclerosis (MS) has not been studied previously in Indian population.

Aim:

In this study we evaluated the association of HLA alleles and OCB in affecting clinical course and disability of MS.

Methods:

Clinical and demographic features of 145 MS patients who had CSF oligoclonal bands (OCB) tested by isoelectric focussing technique were analyzed, disability status estimated, and HLA DRB1 alleles were genotyped.

Results:

OCBs were positive in 53.8% (78/145) of all MS cases. Patients with CSF OCB had more frequent relapses and an association with HLA DRB1*15. Early disease onset and a high annualized relapse rate was associated with HLA DRB1*03 allele. A relapsing remitting course for MS was seen with HLA DRB1*03 & 15 while a progressive disease was associated with DRB1*01. Presence of both OCB and HLA DRB1*13 was significantly associated with disability in this cohort.

Conclusion:

The results of our study suggest that an interaction between immunological and genetic factors may influence disease onset, course, and disability in MS.
Testosterone, cardiomyopathies, and heart failure
Authors: Diaconu Rodica , Donoiu Ionu[Latin Small Letter t with comma below] , Mirea Oana , Bălşeanu Tudor Adrian
Published: January 2021

Testosterone exerts an important regulation of cardiovascular function through genomic and nongenomic pathways. It produces several changes in cardiomyocytes, the main actor of cardiomyopathies, which are characterized by pathological remodeling, eventually leading to heart failure. Testosterone is involved in contractility, in the energy metabolism of myocardial cells, apoptosis, and the remodeling process. In myocarditis, testosterone directly promotes the type of inflammation that leads to fibrosis, and influences viremia with virus localization. At the same time, testosterone exerts cardioprotective effects that have been observed in different studies. There is increasing evidence that low endogenous levels of testosterone have a negative impact in some cardiomyopathies and a protective impact in others. This review focuses on the interrelationships between testosterone and cardiomyopathies and heart failure.