cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.20020751
title: Effects of Forming Processes on Microstructures and Mechanical Properties of A356 Aluminum Alloy Prepared by Self-inoculation Method

description: Semisolid slurry of A356 aluminum alloy was prepared by Self-Inoculation Method (SIM), and the microstructures and solidification behavior of rheo-forming process in different forming processes were researched. The results indicate that semisolid slurry of A356 aluminum alloy can be prepared by Self-Inoculation Method at 600ºC. Primary α-Al particles with fine and spherical morphology are uniformly distributed when the isothermal holding time of slurry is 3 min. The different forming processes for semisolid rheo-forming can be regarded as the effect of cooling rate on rheo-forming. The primary particle sizes and shape factors are gradually increasing with the increase of cooling rate. The sizes of secondary particles are gradually increasing with the decrease of cooling rate, and the amount of secondary particles in the same areas are gradually decreasing with the decrease of cooling rate. The morphologies of eutectic Si are gradually coarsening from fibrous to needle-like in different forming processes, while the sizes and the lamellar spacing of the eutectic Si are gradually increasing with the decrease of cooling rate. The mechanical properties of the semisolid forming components are gradually increasing with the increase of cooling rate and forming pressure.
DOI: 10.6084/m9.figshare.20020751.v1
title: Effects of Forming Processes on Microstructures and Mechanical Properties of A356 Aluminum Alloy Prepared by Self-inoculation Method

description: Semisolid slurry of A356 aluminum alloy was prepared by Self-Inoculation Method (SIM), and the microstructures and solidification behavior of rheo-forming process in different forming processes were researched. The results indicate that semisolid slurry of A356 aluminum alloy can be prepared by Self-Inoculation Method at 600ºC. Primary α-Al particles with fine and spherical morphology are uniformly distributed when the isothermal holding time of slurry is 3 min. The different forming processes for semisolid rheo-forming can be regarded as the effect of cooling rate on rheo-forming. The primary particle sizes and shape factors are gradually increasing with the increase of cooling rate. The sizes of secondary particles are gradually increasing with the decrease of cooling rate, and the amount of secondary particles in the same areas are gradually decreasing with the decrease of cooling rate. The morphologies of eutectic Si are gradually coarsening from fibrous to needle-like in different forming processes, while the sizes and the lamellar spacing of the eutectic Si are gradually increasing with the decrease of cooling rate. The mechanical properties of the semisolid forming components are gradually increasing with the increase of cooling rate and forming pressure.
DOI: 10.6084/m9.figshare.8031128
title: Stability of Nanocomposite Edible Films Based on Polysaccharides and Vitamin C from Agroindustrial Residue

description: The agroindustrial residue from the production of acerola pulp is rich in residual vitamin C. Thus, aiming its extraction and stabilization, this work proposed the nanoparticle (NP) encapsulation via ionic gelation with subsequent preparation of nanocomposites (NC) film based on galactomannan matrix. NP were characterized and their stabilities were evaluated under different storage conditions (incidence of light, temperature and oxidizing atmosphere). The results by Dynamic Light Scattering (DLS) and Scanning Electron Microscopy (SEM) indicated homogeneous morphology, spherical shape and size of ~220 nm. Regarding the stability, the UV-visible spectrophotometric analysis showed a much lower degradation rate for encapsulated vitamin C, resulting in more than 30% of preservation compared with the non-encapsulated systems at the end of 15th day of storage. In agreement, the NC films also resulted in preservation of vitamin C mainly for the test in high temperature, which maintained about 80% of the initial concentration, whereas in the non-encapsulated condition this value fell to 45%. The morphological analysis of these films by SEM indicated good distribution of the NP in the galactomannan matrix. Thus, the results indicate the feasibility of using the encapsulation method to stabilize vitamin C extracted from the agroindustrial residue of acerola.
DOI: 10.6084/m9.figshare.8031128.v1
title: Stability of Nanocomposite Edible Films Based on Polysaccharides and Vitamin C from Agroindustrial Residue

description: The agroindustrial residue from the production of acerola pulp is rich in residual vitamin C. Thus, aiming its extraction and stabilization, this work proposed the nanoparticle (NP) encapsulation via ionic gelation with subsequent preparation of nanocomposites (NC) film based on galactomannan matrix. NP were characterized and their stabilities were evaluated under different storage conditions (incidence of light, temperature and oxidizing atmosphere). The results by Dynamic Light Scattering (DLS) and Scanning Electron Microscopy (SEM) indicated homogeneous morphology, spherical shape and size of ~220 nm. Regarding the stability, the UV-visible spectrophotometric analysis showed a much lower degradation rate for encapsulated vitamin C, resulting in more than 30% of preservation compared with the non-encapsulated systems at the end of 15th day of storage. In agreement, the NC films also resulted in preservation of vitamin C mainly for the test in high temperature, which maintained about 80% of the initial concentration, whereas in the non-encapsulated condition this value fell to 45%. The morphological analysis of these films by SEM indicated good distribution of the NP in the galactomannan matrix. Thus, the results indicate the feasibility of using the encapsulation method to stabilize vitamin C extracted from the agroindustrial residue of acerola.
DOI: 10.6084/m9.figshare.20020752
title: The Effect of Red Pigment and Photo Stabilizers on the Photo Degradation of Polypropylene Films

description: The aim of this work was to evaluate the photo degradation of PP films containing photo stabilizers, a ultraviolet absorber and a hindered amine light stabilizer (HALS), and a red pigment. The films were produced by extrusion and exposed to the UV radiation in the laboratory for up to 15 weeks. The results obtained from FTIR, UV-vis and colorimetry showed that the pigment reduced the rate of chemical degradation both in non-stabilized and photo stabilized films, and the influence was more significant for the combination of pigment and HALS. However, the color shift was more evident when the pigment was present, suggesting that this additive may suffer chemical rearrangements during exposure but do not generate free radicals that can initiate degradation of the polymer. The mechanical properties of the films followed the same trend as the other results, but the unexposed films showed a peculiar behaviour, with much higher tensile strength when the pigments were present. X-ray diffraction and DSC analyses suggested that this might be related to differences in crystal structure.
DOI: 10.6084/m9.figshare.20020752.v1
title: The Effect of Red Pigment and Photo Stabilizers on the Photo Degradation of Polypropylene Films

description: The aim of this work was to evaluate the photo degradation of PP films containing photo stabilizers, a ultraviolet absorber and a hindered amine light stabilizer (HALS), and a red pigment. The films were produced by extrusion and exposed to the UV radiation in the laboratory for up to 15 weeks. The results obtained from FTIR, UV-vis and colorimetry showed that the pigment reduced the rate of chemical degradation both in non-stabilized and photo stabilized films, and the influence was more significant for the combination of pigment and HALS. However, the color shift was more evident when the pigment was present, suggesting that this additive may suffer chemical rearrangements during exposure but do not generate free radicals that can initiate degradation of the polymer. The mechanical properties of the films followed the same trend as the other results, but the unexposed films showed a peculiar behaviour, with much higher tensile strength when the pigments were present. X-ray diffraction and DSC analyses suggested that this might be related to differences in crystal structure.
DOI: 10.6084/m9.figshare.8030945
title: Mechanical Properties and Microstructural Evolution of CuZn Alloys via Pre-Torsional Deformation

description: Mechanical properties and microstructural evolution of Cu-10wt.%Zn and Cu-30wt.%Zn alloys after pre-torsional deformation have been investigated in this study. The results indicated that pre-torsional deformation can significantly enhance the strength of both Cu-10wt.%Zn and Cu-30wt.%Zn alloys without changing their shape and size, but with the sacrifice of the ductility. The pre-torsion deformation can introduce gradient hardness and microstructures along the radial direction, with the microstructures along the radial direction in Cu-30wt.%Zn alloy being "dislocations→stacking faults→twins (low density)". The stacking fault energy affects significantly the microstructure along the radial direction.
DOI: 10.6084/m9.figshare.8030945.v1
title: Mechanical Properties and Microstructural Evolution of CuZn Alloys via Pre-Torsional Deformation

description: Mechanical properties and microstructural evolution of Cu-10wt.%Zn and Cu-30wt.%Zn alloys after pre-torsional deformation have been investigated in this study. The results indicated that pre-torsional deformation can significantly enhance the strength of both Cu-10wt.%Zn and Cu-30wt.%Zn alloys without changing their shape and size, but with the sacrifice of the ductility. The pre-torsion deformation can introduce gradient hardness and microstructures along the radial direction, with the microstructures along the radial direction in Cu-30wt.%Zn alloy being "dislocations→stacking faults→twins (low density)". The stacking fault energy affects significantly the microstructure along the radial direction.
DOI: 10.6084/m9.figshare.20020755
title: Incorporating Aluminum Into the Structure of SBA-15 by Adjusting the pH and Adding NaF

description: The Al incorporation on SBA-15 type material and the effects of pH adjusting and presence of NaF were studied. The direct synthesis method was performed for comparison. The following parameters were evaluated: the Si/Al ratio, pH increase, and amount of NaF added. These parameters have a great influence on the synthesis of the mesoporous Al/SBA-15 type, but the pH the most influential parameter for the incorporation of Al into the SBA-15 structure. The formation of the SBA-15 structure was observed through the direct synthesis method. However, aluminum is not present in the material. The increase in pH contributed to the formation of a disorganized material. By EDX, it was observed that synthesis with a Si/Al = 5 ratio and pH approximately 4 provides materials containing aluminum. When the amount of aluminum during the synthesis is lower, a pH of approximately 8 is required to incorporate aluminum into the final material. The Al-NMR analysis showed that it was possible to insert aluminum in the structure of SBA-15, but with the presence of aluminum hexa and pentacoordinated. In the catalytic test of the dehydration reaction of ethanol, the samples with higher aluminum contents showed better catalytic performance due to its higher acidity.
DOI: 10.6084/m9.figshare.20020755.v1
title: Incorporating Aluminum Into the Structure of SBA-15 by Adjusting the pH and Adding NaF

description: The Al incorporation on SBA-15 type material and the effects of pH adjusting and presence of NaF were studied. The direct synthesis method was performed for comparison. The following parameters were evaluated: the Si/Al ratio, pH increase, and amount of NaF added. These parameters have a great influence on the synthesis of the mesoporous Al/SBA-15 type, but the pH the most influential parameter for the incorporation of Al into the SBA-15 structure. The formation of the SBA-15 structure was observed through the direct synthesis method. However, aluminum is not present in the material. The increase in pH contributed to the formation of a disorganized material. By EDX, it was observed that synthesis with a Si/Al = 5 ratio and pH approximately 4 provides materials containing aluminum. When the amount of aluminum during the synthesis is lower, a pH of approximately 8 is required to incorporate aluminum into the final material. The Al-NMR analysis showed that it was possible to insert aluminum in the structure of SBA-15, but with the presence of aluminum hexa and pentacoordinated. In the catalytic test of the dehydration reaction of ethanol, the samples with higher aluminum contents showed better catalytic performance due to its higher acidity.
DOI: 10.6084/m9.figshare.20020758
title: Dielectric Behavior of α-Ag2WO4 and its Huge Dielectric Loss Tangent

description: The microwave-assisted hydrothermal method was used to obtain α-Ag2WO4. Rietveld refinement confirmed that α-Ag2WO4 is stable in the orthorhombic phase, without secondary phase. However, field-effect scanning electron microscope analysis showed that α-Ag2WO4 nanorods surfaces contain silver nanoparticles, confirmed by the X-ray photoelectron spectroscopy by the peak observed at 374.39 eV. In addition to metallic Ag, other Ag oxidation states were also observed on the surface. Hence, Ag (I) as Ag2O and Ag (I) as Ag2WO4 also were identified. DC measurements exhibited a high capacity of charge storage, nevertheless, with a large loss tangent (0.12 µC.cm-2.V-1) and no residual polarization for the voltage range between -100 V and +100 V. AC measurements at frequencies less than 275 Hz, revealed that ionic polarization is dominant, whereas at frequencies higher than 275 Hz, the electronic behavior predominates. The potential of electromagnetic energy conversion in thermal was observed from loss tangent analysis.
DOI: 10.6084/m9.figshare.20020758.v1
title: Dielectric Behavior of α-Ag2WO4 and its Huge Dielectric Loss Tangent

description: The microwave-assisted hydrothermal method was used to obtain α-Ag2WO4. Rietveld refinement confirmed that α-Ag2WO4 is stable in the orthorhombic phase, without secondary phase. However, field-effect scanning electron microscope analysis showed that α-Ag2WO4 nanorods surfaces contain silver nanoparticles, confirmed by the X-ray photoelectron spectroscopy by the peak observed at 374.39 eV. In addition to metallic Ag, other Ag oxidation states were also observed on the surface. Hence, Ag (I) as Ag2O and Ag (I) as Ag2WO4 also were identified. DC measurements exhibited a high capacity of charge storage, nevertheless, with a large loss tangent (0.12 µC.cm-2.V-1) and no residual polarization for the voltage range between -100 V and +100 V. AC measurements at frequencies less than 275 Hz, revealed that ionic polarization is dominant, whereas at frequencies higher than 275 Hz, the electronic behavior predominates. The potential of electromagnetic energy conversion in thermal was observed from loss tangent analysis.
DOI: 10.6084/m9.figshare.20020760.v1
title: Effect of Warm Rolling on the Corrosion and Mechanical Properties of UNS S32205 Duplex Stainless Steel

description: Duplex stainless steel (DSS) has been considered as an excellent alternative for applications where high corrosion resistance and high mechanical strength are required. Therefore, microstructure and properties of DSS remain topics of much interest. For this purpose, the effect of warm-rolling was studied in a duplex stainless steel. The focus of this work was 2205 which is one of the most useful type of DSS. Although evolution of microstructure, texture and tensile properties during warm rolling of DDS have been reported, there is no study on the effect of warm rolling on corrosion resistance of 2205 DSS. In this context, the objective of this work is to evaluate microstructure, texture and mechanical and corrosion properties of UNS S32205 DSS after warm rolling. The duplex stainless steel was warm-rolled at 600°C up to 60 and 80% thickness reduction and submitted to electrochemical tests. The electrochemical behaviour of warm-rolled 2205 in the chlorine ion environment was evaluated using cyclic potentiodynamic polarization (CPP) and electrochemical impedance spectroscopy (EIS). The samples exhibited an excellent corrosion resistance in 3.5% NaCl solution. The study showed that the thermomechanical treatment used favoured the formation of the passive film and led to a greater polarization resistance. This behaviour is consistent with the pits density observed by scanning electron microscopy (SEM) and the crystallographic microtexture of the steel.
DOI: 10.6084/m9.figshare.20020760
title: Effect of Warm Rolling on the Corrosion and Mechanical Properties of UNS S32205 Duplex Stainless Steel

description: Duplex stainless steel (DSS) has been considered as an excellent alternative for applications where high corrosion resistance and high mechanical strength are required. Therefore, microstructure and properties of DSS remain topics of much interest. For this purpose, the effect of warm-rolling was studied in a duplex stainless steel. The focus of this work was 2205 which is one of the most useful type of DSS. Although evolution of microstructure, texture and tensile properties during warm rolling of DDS have been reported, there is no study on the effect of warm rolling on corrosion resistance of 2205 DSS. In this context, the objective of this work is to evaluate microstructure, texture and mechanical and corrosion properties of UNS S32205 DSS after warm rolling. The duplex stainless steel was warm-rolled at 600°C up to 60 and 80% thickness reduction and submitted to electrochemical tests. The electrochemical behaviour of warm-rolled 2205 in the chlorine ion environment was evaluated using cyclic potentiodynamic polarization (CPP) and electrochemical impedance spectroscopy (EIS). The samples exhibited an excellent corrosion resistance in 3.5% NaCl solution. The study showed that the thermomechanical treatment used favoured the formation of the passive film and led to a greater polarization resistance. This behaviour is consistent with the pits density observed by scanning electron microscopy (SEM) and the crystallographic microtexture of the steel.
DOI: 10.6084/m9.figshare.11966367
title: Study of the Thermal Stability of Faujasite Zeolite Synthesized from Kaolin Waste from the Amazon

description: The waste from the processing of kaolin in the Amazonian region of Brazil was subjected to a calcination process at 700°C for 2 h to obtain metakaolin, which, together with sodium hydroxide and sodium silicate, formed the reaction mixture. This mixture was subjected to an aging step (24 h at 60 rpm), and a subsequent hydrothermal process at 110°C for 10 h. By means of X-ray diffraction (XRD), differential thermal and thermogravimetric analysis (DTA/TG) and scanning electron microscopy (SEM) techniques, the crystallization of a single phase, faujasite (FAU) zeolite, was observed. In the postsynthesis process, it was verified by means of XRD that the thermal stability of this structure persists up to a temperature of 600°C. At 800°C, the structure of FAU collapses. Beginning at 850°C, new nepheline phases are formed, and at 1000°C, nepheline and mullite phases are formed.
DOI: 10.6084/m9.figshare.11966367.v1
title: Study of the Thermal Stability of Faujasite Zeolite Synthesized from Kaolin Waste from the Amazon

description: The waste from the processing of kaolin in the Amazonian region of Brazil was subjected to a calcination process at 700°C for 2 h to obtain metakaolin, which, together with sodium hydroxide and sodium silicate, formed the reaction mixture. This mixture was subjected to an aging step (24 h at 60 rpm), and a subsequent hydrothermal process at 110°C for 10 h. By means of X-ray diffraction (XRD), differential thermal and thermogravimetric analysis (DTA/TG) and scanning electron microscopy (SEM) techniques, the crystallization of a single phase, faujasite (FAU) zeolite, was observed. In the postsynthesis process, it was verified by means of XRD that the thermal stability of this structure persists up to a temperature of 600°C. At 800°C, the structure of FAU collapses. Beginning at 850°C, new nepheline phases are formed, and at 1000°C, nepheline and mullite phases are formed.
DOI: 10.6084/m9.figshare.9957059
title: New Peritectoid Reaction Identified at the MnSb Alloy

description: The tunable Tc region of MnSb alloy (44 - 49 % at. Sb) was analyzed using OM, VSM, DSC, XRD, EDS and XRF characterization techniques. Thermal and magnetic analysis suggests the existence of a non reported irreversible reaction on heating, compatible to a reverse peritectoid transition MnxSb ➔ Mn2Sb + Mnx'Sb.
DOI: 10.6084/m9.figshare.9957059.v1
title: New Peritectoid Reaction Identified at the MnSb Alloy

description: The tunable Tc region of MnSb alloy (44 - 49 % at. Sb) was analyzed using OM, VSM, DSC, XRD, EDS and XRF characterization techniques. Thermal and magnetic analysis suggests the existence of a non reported irreversible reaction on heating, compatible to a reverse peritectoid transition MnxSb ➔ Mn2Sb + Mnx'Sb.
DOI: 10.6084/m9.figshare.8162573
title: Development and Characterization of PbI2 Nanoparticles for all Solid-State Flexible Supercapacitor Purposes

description: The development and utilization of new energy sources has been extensively studied in the world. Here, we report the development of flexible self-supported metal-free electrodes based on non-oxidized graphene multilayer (MLG) paper containing the lead iodide nanoparticles (PbI2-NPs). The PbI2-NPs was obtained and characterized by X-ray diffraction (XDR) and Raman spectroscopy. Supercapacitor containing the PbI2-NPs in MLG electrodes was fabricated by a simple method and characterized using atomic force microscopy (AFM), cyclic voltammetry (CV) and galvanostatic charge-discharge techniques. The results show a flexible supercapacitor fashion reaching capacitance values of 154 F/g with high prospects in electronic area. Energy and power densities obtained for the pure MLG supercapacitor were 3.40 µWh cm-2 and 0.73 mW cm-2, respectively. Regarding to PbI2-NPs/MLG capacitor the energy and power density obtained were 3.50 Wh kg-1 and 1.10 kW kg-1. The results herein presented open the possibility to new energy storage devices using PbI2-NPs and MLG flexible supercapacitor configuration.
DOI: 10.6084/m9.figshare.8162573.v1
title: Development and Characterization of PbI2 Nanoparticles for all Solid-State Flexible Supercapacitor Purposes

description: The development and utilization of new energy sources has been extensively studied in the world. Here, we report the development of flexible self-supported metal-free electrodes based on non-oxidized graphene multilayer (MLG) paper containing the lead iodide nanoparticles (PbI2-NPs). The PbI2-NPs was obtained and characterized by X-ray diffraction (XDR) and Raman spectroscopy. Supercapacitor containing the PbI2-NPs in MLG electrodes was fabricated by a simple method and characterized using atomic force microscopy (AFM), cyclic voltammetry (CV) and galvanostatic charge-discharge techniques. The results show a flexible supercapacitor fashion reaching capacitance values of 154 F/g with high prospects in electronic area. Energy and power densities obtained for the pure MLG supercapacitor were 3.40 µWh cm-2 and 0.73 mW cm-2, respectively. Regarding to PbI2-NPs/MLG capacitor the energy and power density obtained were 3.50 Wh kg-1 and 1.10 kW kg-1. The results herein presented open the possibility to new energy storage devices using PbI2-NPs and MLG flexible supercapacitor configuration.