cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.6273389
title: The Effect of Heat Treatment on Dynamic Strain Aging Behaviour of AISI H10 Hot Work Tool Steel

description: Dynamic strain aging (DSA) behaviour of hot work tool steel (H10) was investigated under as- received (AR) and as-quenched (AQ) conditions. Hot tensile test was carried out in the temperatures of 25°C-700°C at a strain rate of 1x10-3s-1. The tensile properties indicated that AQ samples showed an increase in yield strength (YS) and ultimate tensile strength (UTS) but a decrease in elongation at 200°C or 300°C consistent with DSA. However, AR samples revealed a decrease in YS and UTS for the same testing temperatures. This indicated the presence of less amount of free C or N in solution of AR samples. Further increase in the testing temperature has increased the elongation. It is believed that DSA occurs in H10 tool steel at different temperatures because of interaction between dislocations and interstitial solute atoms (C or N) or substitutional atoms (Cr or Mo).
DOI: 10.6084/m9.figshare.6273389.v1
title: The Effect of Heat Treatment on Dynamic Strain Aging Behaviour of AISI H10 Hot Work Tool Steel

description: Dynamic strain aging (DSA) behaviour of hot work tool steel (H10) was investigated under as- received (AR) and as-quenched (AQ) conditions. Hot tensile test was carried out in the temperatures of 25°C-700°C at a strain rate of 1x10-3s-1. The tensile properties indicated that AQ samples showed an increase in yield strength (YS) and ultimate tensile strength (UTS) but a decrease in elongation at 200°C or 300°C consistent with DSA. However, AR samples revealed a decrease in YS and UTS for the same testing temperatures. This indicated the presence of less amount of free C or N in solution of AR samples. Further increase in the testing temperature has increased the elongation. It is believed that DSA occurs in H10 tool steel at different temperatures because of interaction between dislocations and interstitial solute atoms (C or N) or substitutional atoms (Cr or Mo).
DOI: 10.6084/m9.figshare.6273311
title: Solvothermal Reduction of Graphite Oxide Using Alcohols

description: In the present work, we use either ethanol or ethylene glycol as reducing agents through the solvothermal method for graphite oxide reduction. A sulfuric acid treatment before the reduction process was also applied to evaluate its influence on the epoxy group ring-opening reaction. Reduced graphene oxide (RGO) samples were obtained with morphology like crumpled sheets. X-ray diffraction analyses (XRD) showed that the RGO produced via ethylene glycol (EG) reduction followed by treatment with sulfuric acid (RGOEGH) presented the largest d-spacing (0.4114 nm). For reduction with ethanol (RGOEt), the d-spacing value was 0.3883 nm. Infrared spectroscopy (FTIR) results indicated that RGOEt exhibited very low-intensity bands related to oxygenated functional groups, suggesting a high reduction degree, while the sample reduced with EG contained oxygen group bands in the spectrum that disappeared when H2SO4 pretreatment was performed. Thermal gravimetric analyses (TGA) results showed that the samples present high stability and confirmed the reduction process. Moreover, the synthesized RGO sheets were comparable to those produced via more expensive and toxic methodologies.
DOI: 10.6084/m9.figshare.6273311.v1
title: Solvothermal Reduction of Graphite Oxide Using Alcohols

description: In the present work, we use either ethanol or ethylene glycol as reducing agents through the solvothermal method for graphite oxide reduction. A sulfuric acid treatment before the reduction process was also applied to evaluate its influence on the epoxy group ring-opening reaction. Reduced graphene oxide (RGO) samples were obtained with morphology like crumpled sheets. X-ray diffraction analyses (XRD) showed that the RGO produced via ethylene glycol (EG) reduction followed by treatment with sulfuric acid (RGOEGH) presented the largest d-spacing (0.4114 nm). For reduction with ethanol (RGOEt), the d-spacing value was 0.3883 nm. Infrared spectroscopy (FTIR) results indicated that RGOEt exhibited very low-intensity bands related to oxygenated functional groups, suggesting a high reduction degree, while the sample reduced with EG contained oxygen group bands in the spectrum that disappeared when H2SO4 pretreatment was performed. Thermal gravimetric analyses (TGA) results showed that the samples present high stability and confirmed the reduction process. Moreover, the synthesized RGO sheets were comparable to those produced via more expensive and toxic methodologies.
DOI: 10.6084/m9.figshare.6273299
title: Conducting Behavior of Crystalline α-PbO2 as Revealed by DFT Calculations

description: PbO2 is one material that has recently emerged as potential transparent conducting oxide for applications in the modern opto-electronic industry. In this work the electronic structure of the α-PbO2 polymorph has been investigated, aiming to contribute to the understanding of its high levels of conductivity. DFT calculations using B3LYP hybrid density functional and considering long range interactions among the atoms have been performed. A direct band gap of 0.90 eV has been found, compatible with high conductivity values. Although the stoichiometric material is somewhat transparent, the band structure indicates that appropriated modifications in the material Fermi level can be performed in order to decrease the absorption of light. Charge distribution plus overlap population analysis show that the material is predominantly ionic. The charge distribution throughout the material is strongly dependent on the crystal direction. Results suggest that α-PbO2 can be potentially more interesting for opto-electronic purposes than the β polymorph.
DOI: 10.6084/m9.figshare.6273299.v1
title: Conducting Behavior of Crystalline α-PbO2 as Revealed by DFT Calculations

description: PbO2 is one material that has recently emerged as potential transparent conducting oxide for applications in the modern opto-electronic industry. In this work the electronic structure of the α-PbO2 polymorph has been investigated, aiming to contribute to the understanding of its high levels of conductivity. DFT calculations using B3LYP hybrid density functional and considering long range interactions among the atoms have been performed. A direct band gap of 0.90 eV has been found, compatible with high conductivity values. Although the stoichiometric material is somewhat transparent, the band structure indicates that appropriated modifications in the material Fermi level can be performed in order to decrease the absorption of light. Charge distribution plus overlap population analysis show that the material is predominantly ionic. The charge distribution throughout the material is strongly dependent on the crystal direction. Results suggest that α-PbO2 can be potentially more interesting for opto-electronic purposes than the β polymorph.
DOI: 10.6084/m9.figshare.6272867
title: Corrosion Resistance Evaluation of HVOF Produced Hydroxyapatite and TiO2-hydroxyapatite Coatings in Hanks' Solution

description: The electrochemical behavior of HVOF produced hydroxyapatite (HA) and 80HA-20TiO2 coatings were investigated using electrochemical techniques in natural aerated Hanks' solution in the presence and absence of bovine serum albumin (BSA) for 30 days. All samples presented open circuit potential oscillations, which were associated to the porous nature of the coating that allows the electrolyte reaches the substrate causing activation - passivation at the bottom of the pores. The polarization studies indicated that the 80HA-20TiO2 coating was the only one that showed a narrow potential passive region from around -0.4 V to 0 V in the presence and absence of BSA, indicating the beneficial influence of the addition of TiO2 to the HA coating stability. Our results indicated that BSA in Hanks' solution diminishes the stability of the metallic oxide layer present on the Ti-based alloy accelerating the degrading of hydroxyapatites coatings / substrate interface due to its chelating ability.
DOI: 10.6084/m9.figshare.6272867.v1
title: Corrosion Resistance Evaluation of HVOF Produced Hydroxyapatite and TiO2-hydroxyapatite Coatings in Hanks' Solution

description: The electrochemical behavior of HVOF produced hydroxyapatite (HA) and 80HA-20TiO2 coatings were investigated using electrochemical techniques in natural aerated Hanks' solution in the presence and absence of bovine serum albumin (BSA) for 30 days. All samples presented open circuit potential oscillations, which were associated to the porous nature of the coating that allows the electrolyte reaches the substrate causing activation - passivation at the bottom of the pores. The polarization studies indicated that the 80HA-20TiO2 coating was the only one that showed a narrow potential passive region from around -0.4 V to 0 V in the presence and absence of BSA, indicating the beneficial influence of the addition of TiO2 to the HA coating stability. Our results indicated that BSA in Hanks' solution diminishes the stability of the metallic oxide layer present on the Ti-based alloy accelerating the degrading of hydroxyapatites coatings / substrate interface due to its chelating ability.
DOI: 10.6084/m9.figshare.6273785
title: Effect of Different Synthesis Methods on the Textural Properties of Calcium Tungstate (CaWO4) and Its Catalytic Properties in the Toluene Oxidation

description: Calcium tungstate (CaWO4) crystals were prepared by microwave-assisted hydrothermal (MAH) and polymeric precursor methods (PPM). These crystals were structurally characterized by X-ray diffraction (XRD), N2 adsorption, X-ray absorption near edge spectroscopy (XANES) and extended X-ray absorption fine structure (EXAFS) measurements. The morphology and size of these crystals were observed by field emission scanning electron microscopy (FE-SEM). Their optical properties were investigated by ultraviolet visible (UV-Vis) absorption and photoluminescence (PL) measurements. Moreover, these materials were employed as catalysts towards gas phase toluene oxidation reaction. XRD indicates the purity of materials for both preparation methods and MAH process produced crystalline powders synthesized at lower temperatures and shorter processing time compared to the ones prepared by PPM. FE-SEM images showed particles with rounded morphology and particles in clusters dumbbells-like shaped. PL spectra exhibit a broad band covering the visible electromagnetic spectrum in the range of 360 to 750 nm. XANES and EXAFS results show that preparation method does not introduce high disorders into the structure, however the H2-TPR results indicated that the catalyst reducibility is affected by the preparation method of the samples.
DOI: 10.6084/m9.figshare.6273785.v1
title: Effect of Different Synthesis Methods on the Textural Properties of Calcium Tungstate (CaWO4) and Its Catalytic Properties in the Toluene Oxidation

description: Calcium tungstate (CaWO4) crystals were prepared by microwave-assisted hydrothermal (MAH) and polymeric precursor methods (PPM). These crystals were structurally characterized by X-ray diffraction (XRD), N2 adsorption, X-ray absorption near edge spectroscopy (XANES) and extended X-ray absorption fine structure (EXAFS) measurements. The morphology and size of these crystals were observed by field emission scanning electron microscopy (FE-SEM). Their optical properties were investigated by ultraviolet visible (UV-Vis) absorption and photoluminescence (PL) measurements. Moreover, these materials were employed as catalysts towards gas phase toluene oxidation reaction. XRD indicates the purity of materials for both preparation methods and MAH process produced crystalline powders synthesized at lower temperatures and shorter processing time compared to the ones prepared by PPM. FE-SEM images showed particles with rounded morphology and particles in clusters dumbbells-like shaped. PL spectra exhibit a broad band covering the visible electromagnetic spectrum in the range of 360 to 750 nm. XANES and EXAFS results show that preparation method does not introduce high disorders into the structure, however the H2-TPR results indicated that the catalyst reducibility is affected by the preparation method of the samples.
DOI: 10.6084/m9.figshare.6503435.v1
title: Study of Mechanical and Wear Behaviour of Hyper-Eutectic Al-Si Automotive Alloy Through Fe, Ni and Cr Addition

description: Effect of Fe, Ni and Cr addition on the wear behavior of hyper-eutectic Al-Si automotive alloy has been studied. Dry sliding wear tests have been conducted using pin-on-disc wear testing machine under normal loads of 20N and constant sliding speed of 0.64 ms-1. Influence of Fe addition to the base alloy increases the wear rate due to the formation of needle beta intermetallics. Ni addition to the alloy does not impede formation of needle-like intermetallic compounds and has no positive effect on the modification of microstructure. Introducing of Cr to the iron-rich alloy changes the beta intermetallics into the modified alpha phases and therefore reduced the detrimental effect of iron. As a result it recovers the strength and wear properties of the experimental alloy. Wear test surfaces were examined by SEM and have shown that Cr added alloy improves wear resistance through mild and smooth abrasive grooves filled with oxides.
DOI: 10.6084/m9.figshare.6503435
title: Study of Mechanical and Wear Behaviour of Hyper-Eutectic Al-Si Automotive Alloy Through Fe, Ni and Cr Addition

description: Effect of Fe, Ni and Cr addition on the wear behavior of hyper-eutectic Al-Si automotive alloy has been studied. Dry sliding wear tests have been conducted using pin-on-disc wear testing machine under normal loads of 20N and constant sliding speed of 0.64 ms-1. Influence of Fe addition to the base alloy increases the wear rate due to the formation of needle beta intermetallics. Ni addition to the alloy does not impede formation of needle-like intermetallic compounds and has no positive effect on the modification of microstructure. Introducing of Cr to the iron-rich alloy changes the beta intermetallics into the modified alpha phases and therefore reduced the detrimental effect of iron. As a result it recovers the strength and wear properties of the experimental alloy. Wear test surfaces were examined by SEM and have shown that Cr added alloy improves wear resistance through mild and smooth abrasive grooves filled with oxides.
DOI: 10.6084/m9.figshare.20020724
title: Cell and Bacteria-Baterial Interactions on the Ti10Mo8Nb Alloy After Surface Modification

description: The purpose of this study is the surface modification of Ti10Mo8Nb experimental alloy by using TiO2 nanostructure growth. Ingots of the Ti10Mo8Nb experimental alloy were produced by fusion from sheets of molybdenum, niobium, and titanium commercially pure in an arc melting furnace under argon atmosphere. The potentiostatic anodic oxidation was performed using an electrolyte formed of glycerol and H2O (1: 1 by vol.) with the addition of 2.7% (w/v) NH4F under 20 V for 3 h at room temperature. After the surface treatment, the samples were annealing. The surface of the alloy was analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), contact angle, surface energy measurements. In vitro studies, such as cell and bacterial adhesion, were performed to evaluate the response of this treatment. The Ti10Mo8Nb alloy exhibited beta phase after the processing. After the surface treatment, a nanoporous layer of TiO was obtained. The anatase phase was found in the annealed samples (450 ºC for 3 hours). In vitro analyzes showed cell growth viability and decreased bacterial proliferation due to the larger specific surface area.
DOI: 10.6084/m9.figshare.20020724.v1
title: Cell and Bacteria-Baterial Interactions on the Ti10Mo8Nb Alloy After Surface Modification

description: The purpose of this study is the surface modification of Ti10Mo8Nb experimental alloy by using TiO2 nanostructure growth. Ingots of the Ti10Mo8Nb experimental alloy were produced by fusion from sheets of molybdenum, niobium, and titanium commercially pure in an arc melting furnace under argon atmosphere. The potentiostatic anodic oxidation was performed using an electrolyte formed of glycerol and H2O (1: 1 by vol.) with the addition of 2.7% (w/v) NH4F under 20 V for 3 h at room temperature. After the surface treatment, the samples were annealing. The surface of the alloy was analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), contact angle, surface energy measurements. In vitro studies, such as cell and bacterial adhesion, were performed to evaluate the response of this treatment. The Ti10Mo8Nb alloy exhibited beta phase after the processing. After the surface treatment, a nanoporous layer of TiO was obtained. The anatase phase was found in the annealed samples (450 ºC for 3 hours). In vitro analyzes showed cell growth viability and decreased bacterial proliferation due to the larger specific surface area.
DOI: 10.6084/m9.figshare.20020727
title: Effects of Potential Deposition on the Parameters of ZnO dye-sensitized Solar Cells

description: Dye-sensitized solar cells (DSSCs) are a feasible option for photovoltaic energy. Zinc oxide is an n-type semiconductor employed as photoanode on DSSCs. ZnO thin films were electrodeposited to study the effects of different potentials applied during deposition. SEM images, XRD and UV-Vis analysis were conducted to reveal the morphologic, structural and optical properties of the films at three potentials. DSSCs were assembled and the photovoltaic parameters were obtained through J-V plots. DSSC with 0.031% of efficiency was demonstrated at -1.4 V of deposition potential.
DOI: 10.6084/m9.figshare.20020727.v1
title: Effects of Potential Deposition on the Parameters of ZnO dye-sensitized Solar Cells

description: Dye-sensitized solar cells (DSSCs) are a feasible option for photovoltaic energy. Zinc oxide is an n-type semiconductor employed as photoanode on DSSCs. ZnO thin films were electrodeposited to study the effects of different potentials applied during deposition. SEM images, XRD and UV-Vis analysis were conducted to reveal the morphologic, structural and optical properties of the films at three potentials. DSSCs were assembled and the photovoltaic parameters were obtained through J-V plots. DSSC with 0.031% of efficiency was demonstrated at -1.4 V of deposition potential.
DOI: 10.6084/m9.figshare.20020728
title: Effect of Residual Stresses of GTA Welding for Dissimilar Materials

description: The purpose of the present work is to understand the evolution of residual stresses in weldments. The study made to weld the multipass dissimilar of Nickel-based superalloy Inconel 625 and stainless steel 316L using Continuous Current Gas Tungsten Arc Welding (CCGTAW) and Pulsed Current Gas Tungsten Arc Welding (PCGTAW) process employing ERNiCrMo-3 and ERNiCr-3 fillers. The L4 orthogonal array was used in the present experimentation process. Analysis of Variance (ANOVA) is applied for the optimization and to identify the critical parameters. In welding process, the size of the lattice size will be stressed due to welding parameters; the lattice dimension is measured by non-destructive technique X-Ray diffraction to investigate residual stress in the weldment in the lateral surface of the plate. X-Ray Radiography test has evaluated the quality of welds. The results show that root gap is a critical parameter and filler wire and weld processes are not critical.
DOI: 10.6084/m9.figshare.20020728.v1
title: Effect of Residual Stresses of GTA Welding for Dissimilar Materials

description: The purpose of the present work is to understand the evolution of residual stresses in weldments. The study made to weld the multipass dissimilar of Nickel-based superalloy Inconel 625 and stainless steel 316L using Continuous Current Gas Tungsten Arc Welding (CCGTAW) and Pulsed Current Gas Tungsten Arc Welding (PCGTAW) process employing ERNiCrMo-3 and ERNiCr-3 fillers. The L4 orthogonal array was used in the present experimentation process. Analysis of Variance (ANOVA) is applied for the optimization and to identify the critical parameters. In welding process, the size of the lattice size will be stressed due to welding parameters; the lattice dimension is measured by non-destructive technique X-Ray diffraction to investigate residual stress in the weldment in the lateral surface of the plate. X-Ray Radiography test has evaluated the quality of welds. The results show that root gap is a critical parameter and filler wire and weld processes are not critical.
DOI: 10.6084/m9.figshare.20020730
title: Effect of Martensitic Transformation on Elastic Modulus Anisotropy of Ti-6Al-4V Alloy

description: The Young's modulus (E), Poisson's ratio (ν) and anisotropy parameter (AG) of α' phase, which obtained from different solution treatment and water quenching temperature, were investigated using first-principles calculations based on density functional theory (DFT). The calculation results showed that the Z-axis value of the elastic modulus of α' phase was higher than that of the X-axis and the Y-axis, indicating the elastic modulus of α' phase was anisotropic. It was decreased with increasing the solution treatment and water quenching temperature for the elastic modulus anisotropy of α' phase. In order to verify the calculation results, the elastic modulus anisotropy of macroscopic Ti-6Al-4V alloys, which were treated at 850ºC, 900ºC and 950ºC, were tested by the tensile and the compressive experiments. The experimental results showed the same change tendency with the calculation results. It concluded that the elastic modulus anisotropy of macroscopic alloy could be controlled by the elastic modulus anisotropy of α' phase.
DOI: 10.6084/m9.figshare.20020730.v1
title: Effect of Martensitic Transformation on Elastic Modulus Anisotropy of Ti-6Al-4V Alloy

description: The Young's modulus (E), Poisson's ratio (ν) and anisotropy parameter (AG) of α' phase, which obtained from different solution treatment and water quenching temperature, were investigated using first-principles calculations based on density functional theory (DFT). The calculation results showed that the Z-axis value of the elastic modulus of α' phase was higher than that of the X-axis and the Y-axis, indicating the elastic modulus of α' phase was anisotropic. It was decreased with increasing the solution treatment and water quenching temperature for the elastic modulus anisotropy of α' phase. In order to verify the calculation results, the elastic modulus anisotropy of macroscopic Ti-6Al-4V alloys, which were treated at 850ºC, 900ºC and 950ºC, were tested by the tensile and the compressive experiments. The experimental results showed the same change tendency with the calculation results. It concluded that the elastic modulus anisotropy of macroscopic alloy could be controlled by the elastic modulus anisotropy of α' phase.
DOI: 10.6084/m9.figshare.6693317
title: Chitosan/NaF Particles Prepared Via Ionotropic Gelation: Evaluation of Particles Size and Morphology

description: The aim of this work was to perform an analysis of the influence of Sodium Fluoride (NaF) on chitosan particles size and morphology produced via ionotropic gelation with higher rotational stirring speed. Samples were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Dynamic Light Scattering (DLS), Zeta Potential (ζ), Scanning Electron Microscopy and Energy Dispersive Spectroscopy (SEM/EDS). Chitosan/TPP particles diameter obtained was in the order of 3.8 µm. When NaF was added in different concentration (0.05%, 0.2% and 2%), the particle size diameter values, Zeta Potential and Poly Dispersive Index measures consequently decreased. Even so, no further modification in morphology was found. An exception was made for the samples with higher NaF concentration. After 21 days, occurred an increase in the particle size diameter. In the future, the proposed methodology could provide a dentistry application, especially on delivering particles of NaF.