bluuebunny/crossref_metadata_2025_split huggingface dataset:
Risco elevado do desenvolvimento das doenças crônicas não transmissíveis em cuidadores de pessoas idosas
Authors: Oliveira Filho Vilmar da Conceição , Sá Selma Petra Chaves , De Souza Rocha Gabrielle , Domingos Ana Maria , Soares Rafael da Silva , Barroso Taianah Almeida 
Published: July 2021

Introdução: A baixa qualidade de vida associada ao sobrepeso e a circunferência abdominal elevada em cuidadores, demonstra ser um fator de risco para o desenvolvimento de doenças crônicas não transmissíveis. Objetivo: Relacionar características sociodemográficas, antropométricas com a qualidade de vida de cuidadores. Método: Estudo transversal, com 31 cuidadores, atendidas no Centro de Atenção à Saúde do Idoso e seus Cuidadores. Responderam um questionário sociodemográfico e realizaram antropometria com as seguintes variáveis: peso, estatura, circunferência abdominal (CAb) e cálculo do índice de massa corporal (IMC), a CAb e o IMC foram classificados segundo a Organização Mundial da Saúde, 2000. A qualidade de vida foi mensurada pela escala SF-36. No tratamento de dados foram realizados os testes de Shapiro Wilk e Mann-Whitney no software SPSS (22.0). Resultados: 45,16% eram formais, 61,3% possuíam o ensino médio completo e 38,8% ganhavam 2 salários mínimo ou menos. A obesidade foi de 35,5% e de CAb maior que 88 cm foi 71,1%. Observou-se que cuidadores, no geral, apresentavam pior qualidade de vida nos domínios dor e estado geral. Conclusão: Os cuidadores apresentaram baixa renda, nível de escolaridade variado, predomínio significativo do sobrepeso e circunferência abdominal elevada. A qualidade de vida apresentou associação com o estado nutricional.
Anode Boundary Layer Effects in Plasma Spray Torches
Authors: Duan Z. , Heberlein J. 
Published: July 2021

Abstract
The control over coating quality in plasma spraying is partly dependent on the arc and jet instabilities of the plasma torch. Different forms of instabilities have been observed with different effects on the coating quality. We report on an investigation of these instabilities based on high-speed end-on observation of the arc. The framing rate of 40,500 frames per second has allowed the visualization of the anode attachment movement and the determination of the thickness of the cold gas boundary layer surrounding the arc. The images have been synchronized with voltage traces. Data have been obtained for a range of arc currents, mass flow rates, for different gas injectors and for anodes displaying different amounts of wear. The analysis of the data has led to quantitative correlations between the cold gas boundary layer thickness and the instability mode for the range of operating parameters. The arc instabilities can be seen to enhance the plasma jet instabilities and the cold gas entrainment. These results are particular useful for guiding plasma torch design and operation to minimize the influence of plasma jet instabilities on coating properties.
Diagnostics and Applications of an Innovative Plasma Torch Generating a Broad Plasma Jet
Authors: Hartmann R. , Landes K.D. 
Published: July 2021

Abstract
Conventional DC plasma torch designs lead to a circular cross-section of the emanating plasma jet. Consequently in surface treatment applications the plasma jet hits the substrate within a limited circular working area. Large scale workpieces therefore have to be scanned resulting in a time-consuming procedure. The innovative DC plasma torch system LARGE is characterized by the arrangement of the anode and the cathode opposite to each other on a common axis with a variable distance. The central body of the torch between the electrodes is divided into electrically insulated cascade plates. The plasma gas is injected perpendicular to the torch axis. Passing through the arc, the gas is transferred to the plasma state and leaves the torch laterally through a slit as a plasma jet with extended stripe width. The plasma torch LARGE is investigated by electrical, optical and enthalpy probe diagnostics. Shrouding the electrodes with an inert gas and feeding reactive gas mixtures as main plasma gas allow the torch to be used for plasma chemical reactions, too. Preliminary applications focus on preheating, surface modification of paper and plastic materials as well as on sterilization of nutrition packaging. The capability of plasma enhanced CVD is examined experimentally.
Influence of Plasma Spraying Parameters on Coating Damage
Authors: Bianchi L. , Baradel N. , Llorca-Isern N. , Bertran-Vidai G. 
Published: July 2021

Abstract
The influence of plasma spraying parameters on the mechanical properties of coatings has been studied. ZrO2-Y2O3 coatings were sprayed onto stainless steel and aluminium substrates at temperatures of about 75°C and 225°C. An original set of samples, facilitating the measurement of substrate deflection, was used to evaluate the effect of thermal cycling under different spraying conditions. In order to correlate thermal cycling values and mechanical properties to coating microstructure, the coatings were impregnated with low-viscosity resin and examined under a confocal microscope. The results reveal the influence of spraying temperature, substrate properties, and torch-substrate velocity on coating damage.
Study of the Air Entrainment Within dc Plasma Jets
Authors: Lagnoux O. , Coudert J.F. , Wittmann K. , Fauchais P. 
Published: July 2021

Abstract
Air entrainment in the first 30 mm of a dc Ar/ H2 plasma jet has been studied by emission spectroscopy. The tests were conducted using 6, 7 and 10-mm diameter nozzles and plasma arc currents of 400 and 600 A. Oxygen, nitrogen, and argon spectral lines were recorded 20 and 30 mm downstream of the nozzle exit during spraying, and the corresponding atom density ratios were estimated based on plasma population temperature and volumetric emission coefficients. The results indicate that at 20 mm air entrainment is mainly due to piston flow for the 10-mm nozzle and both piston flow and engulfment for the 7-mm nozzle. At 30 mm, the engulfment process is found to have 4 to 6 times the impact that it does at 20 mm and is directly linked to the jet velocity. At both locations, the atom density ratios differ from that observed in air due to the time required to dissociate N2.
The Capabilities and Limitations of Pulsed Plasma, Electrical, Chemical Thermal Spray
Authors: Factor M. , Roman I. , Wald S. 
Published: July 2021

Abstract
A new thermal spray technology has been proposed. Called Electrical Chemical Thermal Spray (ETCS), it combines plasma energy with the combustion gases of solid propellants to heat and accelerate particulate materials. The hybrid technology promises new degrees of freedom in materials processing over the conventional thermal spray processes by allowing thermal energy transfer to the particles and particle accelerations to be optimized separately. Experimental coatings were formed using a prototype system made from a converted ½” plasma gun fueled with double-base solid propellants to explore this novel concept. The prototype test-facility equipment was limited to single-shot mode. Examination of the coatings formed, and conceptual analysis by analogy to conventional technologies was used to assess the capabilities and limitations of the hybrid process. Impressive in-flight powder velocities of 1100 m/s were reached, with deposition yield efficiencies of 60 - 85% achieved for WC-Co coatings after first round of optimization. However despite the ability to deposit single-shot carbide and metallic coatings with thickness exceeding 200 µm. chemical degradation and extensive cracking combined to limit attractiveness of coatings as compared to those produced using commercial technologies. Unlike the oxidation effects with atmospheric plasma spray and the various low-velocity flame-spraying technologies, chemical degradation in the prototype ETCS was the result of interaction between the gases produced from the combustion of the propellant and the coating material. It is seen that the organic, nitrocellulose based solid propellants are inherently unsuitable for spraying reactive material. With suitable fuels however, it is believed that the inherent advantages of high throughput, versatility and low labour requirements are such that ETCS will have commercial advantages for the coating of large structures.
Numerical Modeling of Particle Laden Flow in HVOF Torch with Gas Shroud
Authors: Dolatabadi A. , Mostaghimi J. , Ivanovic M. 
Published: July 2021

Abstract
A particle laden flow in an HVOF torch is analyzed using Computational Fluid Dynamics (CFD). The torch is similar to the DJ Metco torch with a converging-diverging (de Laval) nozzle, where particles are injected through the center together with nitrogen as a carrier gas. The Eulerian formulation is used for the gas flow whereas the particle motion is described by using the Lagrangian formulation. The flow turbulence is modeled via k-e model with standard wall functions. For modeling the combustion process in the torch, a multi-reaction Eddy-Dissipation Model (EDM) is employed. The computational domain comprised the torch itself and the region outside the torch where our attention is mainly focused. The computations are performed for the torch with and without the gas shroud attachment. The results showed that the presence of the shroud affected to some degree the flow and temperature fields of the main gas and the particle stream, while at the same time, significantly reducing the entrainment of ambient air into the main stream as shown by the lower oxygen concentrations. The results of the numerical computations are compared with experimental results for the same operating conditions and the agreement is found to be good.
Process Maps for Plasma Spray Part II: Deposition and Properties
Authors: Jiang X. , Matejicek J. , Kulkarni A. , Herman H. , Sampath S. , Gilmore D.L. , Neiser R.A. 
Published: July 2021

Abstract
This is the second paper of a two part series based on an integrated study carried out at the State University of New York at Stony Brook and Sandia National Laboratories. The goal of the study is the fundamental understanding of the plasma-particle interaction, droplet/substrate interaction, deposit formation dynamics and microstructure development as well as the deposit properties. The outcome is science-based relationships, which can be used to link processing to performance. Molybdenum splats and coatings produced at three plasma conditions and three substrate temperatures were characterized. It was found that there is a strong mechanical /thermal interaction between droplet and substrate, which builds up the coating/substrate adhesion. Hardness, thermal conductivity increase, oxygen content and porosity decreases with increase of particle velocity. Increasing deposition temperature resulted in dramatic improvement in coating thermal conductivity and hardness as well as increase in coating oxygen content. Indentation reveals improved fracture resistance for the coatings prepared at higher deposition temperature. Residual stress was significantly affected by deposition temperature, although not to a great extent by particle conditions within the investigated parameter range. Coatings prepared at high deposition temperature with high-energy particles suffered considerably less damage in a wear test. The mechanism behind these changes is discussed within the context relational maps which is under development.
Thermal Shock Testing and Finite Element Modeling of Pre-Oxidized Thermal Barrier Coatings
Authors: Liu Y. , Persson C. , Bengtsson P. , Leger A.C. , Wigren J. 
Published: July 2021

Abstract
To determine the effect of bond coat oxidation on the coating life, thermal shock testing were performed, using three different thermal cycles. The failure mode and crack paths were investigated in scanning electron microscope. A finite element model was developed to simulate the thermal shock tests. First, transient temperature fields during the thermal cycling were calculated. Second, stresses and strains evolving in the coatings due to thermal expansion mismatches and temperature gradients during the cycling were computed. The stress concentration at the interface due to the roughness of the bond coat was accounted for by using an ideal sinusoidal interface in the model. By adding an oxide layer with and without residual stresses to the model, the influence of the bond coat oxidation was determined. Both the experimental and numerical results revealed that the TBC failed by crack initiating in the ceramic top coat very close to the grown oxide layer at the interface followed by coating fatigue failure. Numerical simulation indicated that bond coat oxidation led to stress concentration at the peak of the asperity of the interface proceeding crack growth. It also showed that bond coat inelasticity and ceramic creep might further enhance the crack growth. There was little effect on coating behavior due to the residual stresses in the oxide layer.
Mathematical Model of In-Flight Oxidation of Metallic Particles in Thermal Spraying
Authors: Ahmed A.M. , Rangel R.H. , Sobolev V.V. , Guilemany J.M. 
Published: July 2021

Abstract
This paper presents a mathematical model of the in-flight oxidation of spherical particles during thermal spray deposition process. The model includes analysis of the mechanical and thermal behavior of the powder particles. The former accounts for acceleration and deceleration of the particles at the spray distance under different fluid velocities. The thermal behavior takes into account heating, melting, cooling and possible solidification as the particle travel towards the substrate. A finite-difference method is used to solve the thermal energy conservation equation of the particles. The model includes nonequilibrium calculations of the phase change phenomena in the liquid-solid (mushy) zone. The growth of the oxide layer at the particle surface is represented by a modified boundary condition, which includes finite-rate oxidation. The results obtained give the interrelations between various process parameters and the oxidation phenomenon and agree with experimental observation.
Computer Aided Coating Design
Authors: Wilden J. , Frank H. , Müller T. 
Published: July 2021

Abstract
The crystal structure of the coating depends on the splashing and solidification of the sprayed particles. The splashing of the particles is simulated by commercial software taking temperature dependent parameters like melt viscosity and surface tension into account. This article provides the theoretical background and the experimental verification. The steps of simulation solidification, splashing, and heat and momentum transfer help to develop novel coating systems with defined microstructure and shorten the time to market. Experimental investigations were carried out using Ni and Ni/Cr 80/20 spray powders with a mean particle diameter of about 15 μm. The theoretical investigations to describe the flattening process of a droplet show the influence of particle velocity and temperature. It was shown that different material parameters, as latent heat or surface energy, have a significant influence on the simulation results.
Structure and Adhesion of Ni and Ni-WC Plasma Spray Coatings
Authors: Coyle T.W. , Bahrami A. 
Published: July 2021

Abstract
There is typically a large scatter in the observed failure stress, particularly for ceramic coatings. Failure can thus occur not only at the coating-substrate interface where it is desired but also through the coating, the bonding epoxy, or the epoxy/coating interface. A large number of alternative test configurations have been proposed in an attempt avoid such drawbacks, each with their advantages and disadvantages. A test method developed recently by Troczynski and co-workers, known as the Peel Adhesion Test, is of particular interest for this article. The first specimens examined were Ni-WC coatings applied to 150 micrometer thick 1010 stainless steel foils which were grit blasted in the same manner as a bulk substrate would have been. It was observed that the technique appears to offer the capability of providing a sensitive and reproducible measure of the effects of surface treatments and other deposition parameters on coating adhesion.
Study of Photo-Catalytic Character of Plasma Sprayed TiO2 Coatings
Authors: Ohmori A. , Shoyama H. , Matsusaka S. , Ohashi K. , Moriya K. , Moriya K. , Li C.J. 
Published: July 2021

Abstract
Two types of rutile and anatase powders are used for the deposition of TiO2 coatings. The effects of plasma spraying conditions on the structure of TiO2 coatings are investigated in order to clarify controlling factors of the phase formation and to aim at the development of effective photo-catalyst TiO2. It is found that the amount of anatase TiO2 in the coating is influenced by spray parameters. The decrease of the heat input to spray droplet and an increase in the cooling speed during droplet deposition will increase the amount of the anatase TiO2 in the coating. As a photo-catalyst, the coating deposited under limited plasma power and by HVOF spraying using anatase powder is effective for the decomposition of acetaldehyde gas.
Investigating High Temperature Damping Behavior of Plasma Sprayed Ni-Alloy Coatings
Authors: Khor K.A. , Chia C.T. , Gu Y.W. 
Published: July 2021

Abstract
In recent year, there has been an increasing trend to design the turbine coating together with the substrate. In this harsh environment, a failure in one quickly leads to a failure in the other. Materials that are used in structural applications are prone to mechanical vibration which when not attenuated, will lead to fatigue of components and shortening of life cycle. Therefore, it is not uncommon to find that it is important to understand the thermal stability and dynamic mechanical properties of coatings as well, which will be used in the dynamic conditions. In addition to these essentially noise reduction and vibration amplitude control motivated objectives, however, mechanical energy dissipation processes also find intrinsic applications in cases where a thorough understanding of the mechanisms responsible for the damping response of the material are required. This article describes the damping behavior and mechanisms that exist in plasma sprayed NiCoCrAlY coatings.
Structure and Properties of Plasma-Sprayed Zircon Coating
Authors: Suzuki M. , Sodeoka S. , Inoue T. , Shimosaka K. , Oki S. 
Published: July 2021

Abstract
Effects of spray parameters, such as spray distance, SD, and substrate temperature, Ts, and post heat treatment on the structure and properties of plasma-sprayed zircon coatings were investigated. Zircon was totally decomposed by plasma spray; the coatings were composed of tetragonal zirconia (t-ZrO2) and amorphous silica (a-SiO2), because of the rapid cooling of molten particle right after the impingement to the substrate. Porosity of the as-sprayed coatings was highly affected by both of substrate temperature and spray distance. In all range of the spray distance which had been tried in this study, higher substrate temperature resulted in lower porosity of the coatings; the coating with porosity of 2% was obtained at Ts = 1573K with SD = 95mm. Porosity also decreased with decrease of spray distance. By the heat treatment at 1473K, t-ZrO2 transformed to monoclinic zirconia (m-ZrO2) and a-SiO2 crystallized to cristobalite, respectively. Cracks in the coating disappeared, and open porosity decreased. This can be attributed to sintering of SiO2 and phase transformation of ZrO2. After the heat treatment at 1673K, the coating was composed of ZrSiO4 with dispersed fine m-ZrO2 particle. Open porosity of all the coatings increased up to 10% at this temperature. This is because of volume shrinkage during the formation of zircon.
Characterization of Thermal Spray Coatings Used for Dimensional Restoration
Authors: McGrann R.T.R. , Kim J. , Shadley J.R. , Rybicki E.F. , Ingesten N.-G. 
Published: July 2021

Abstract
Thick thermal spray coatings are used to repair worn parts during aircraft overhaul. The thermal spray coating is used to restore a part to its original dimensions. Characteristics of the as-applied coating that affect the performance of thermal sprayed parts are the residual stress in the coating, the tensile bond strength, the amount of porosity, oxides and impurities near the coating/substrate interface, and the hardness of the coating. An understanding of the relation of these coating characteristics to process variables such as the material used for the coating, spray process, spray angle, and thickness of the applied material is needed. In this paper, four thermal spray coatings, Ni5Al, Ni5Al-atomized, (NiCr)6Al, and Inco 718, on a substrate of Hastelloy X are investigated. These materials are applied using two different thermal spray application processes: plasma spray and High Velocity Oxy-Fuel (HVOF). Spray angles of 90° and 45° are used during spraying. The nominal thickness of the applied coatings ranges from 0.4 mm to 1.8 mm. The thermal spray coatings are evaluated in four types of tests. Residual stresses in the coatings and substrate are evaluated using the modified layer removal method. A tensile bond strength test is performed. Metallographic examination is used to determine the porosity and content of oxides and bond zone impurities (percent) of the applied materials. In addition, the hardness of the coating is measured. For the materials and conditions investigated, it is found that residual stress varies with each of the four process parameters. The bond strength for plasma sprayed coatings is related to the type of material and possibly to the coating thickness. The percent porosity varies with coating material, but, for Ni5Al, it does not depend on application process. Oxide content, as a percentage, varies with material and process, but not with spray angle and thickness. The percentage of impurities near the coating/substrate interface varies with process and, for the specimens that were coated using the HVOF process, with thickness. The hardness of the coating was found to vary with material and spray process. For three of the four coatings, hardness increases with thickness but, for Inco 718, hardness decreases as thickness increases.
Processing Effects on Residual Stress in Ni+5%AI Coatings–Comparison of Different Spraying Methods
Authors: Matejicek J. , Sampath S. , Gnaeupel-Herold T. , Prask H.J. 
Published: July 2021

Abstract
Properties of thermally sprayed coatings, including residual stress, are controlled by various parameters of the spraying process. This study is focused on three thermal spraying techniques with significantly different particle temperatures and velocities. These are plasma spraying, twin wire arc spraying and high velocity oxy-fuel spraying. For each method, in-flight particle diagnostics was performed. Through-thickness residual stress profiles in Ni+5%A1 coatings on steel substrates were determined nondestructively by neutron diffraction. The stresses range from high tensile in the plasma sprayed coating to compressive in the HVOF one. Various stress generation mechanisms, including splat quenching, peening, and thermal mismatch, are discussed with respect to process parameters and material properties.