cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.9871022.v1
title: Influence of shielding gas composition on the residual stresses of DP600 steel joints welded by GMAW process

description: ABSTRACT The automotive industry has been investing in new manufacturing processes that improve productivity without loss of quality. However, the presence of residual stress (RS), generated in all manufacturing processes, is one of the major problems encountered in the metalworking industry, since these can add up to external loading stresses and cause catastrophic failures in equipment and components. Since welding is one of the most widely used manufacturing processes, it is necessary to know how the welding parameters impact on the nature and magnitude of the residual stresses generated. The shielding gases are used in some welding processes and can be influence the conductivity of the electric arc, which can be affected the residual stresses behavior in the welded joints. In this work an experimental study was carried out about the influence of the percentage of CO2 on the argon-based shielding gases in the residual stresses generated on joints of high strength steel DP600 welded by GMAW process (widely used in the automotive industry). The residual stresses were measured by X-ray diffraction by the sin2ψ method. An assessment of the microstructural morphology by optical microscope (OM) was made. The results showed that the residual stresses have a tensile nature, of the order of 120 MPa, in all samples, which used shielding gas with a lower percentage of CO2.
DOI: 10.6084/m9.figshare.9871025.v1
title: Effect of surface roughness and lubrication on the friction coefficient in deep drawing processes of aluminum alloy aa1100 with fem analysis

description: ABSTRACT Friction between the interface workpiece and tooling has considerable importance in sheet metal forming operations; an accurate description of the friction is necessary to analyze and design new workpieces and tooling. This work suggests a methodology to determine and evaluate the mean coefficient of friction (COF) using the Finite Element Method (FEM) through Dynaform for the aluminum alloy AA1100. The results indicate that this methodology is consistent with reality. It is also observed that the software tends to diverge from the measured results because the software considers the COF to be constant along the process. Despite this trend, the greatest distance between the maximum drawing force given by the measurement and the numeric simulation was not high: it was approximately 6%. Workpiece strain measurements were collected to compare with the numerical simulation results, and it was observed that they are generally in agreement.
DOI: 10.6084/m9.figshare.9871013
title: Effect of furfurylation on physical and mechanical properties of Pinus elliottii wood

description: ABSTRACT Pinus wood presents undesirable characteristics that can be attenuated with the application of treatments, in which the furfurylation is highlighted. Therefore, the objective of this work was to evaluate the effect of impregnation of furfuryl alcohol on the physical and mechanical properties of Pinus elliottii wood. For this, 4 treatments were used: control and with different loads of furfuryl alcohol (10%, 25% and 50%). The properties were determined as described in ASTM D 2395-17 (2017) and ASTM D 143-94 (2014). It was verified that, for the mechanical properties, the compression resistance parallel to the fibers, in which the MOE parameter had a significant increase for all the treatments in relation to the control group, especially for treatment (TF25%), for the MOR, higher values were obtained, but without significant differences. Regarding Janka hardness, the maximum tension in the transverse anatomical plane, higher values were observed when compared to the control, with emphasis on treatment (TF50%), which showed higher values with significant difference. For the tangential plane, no significant differences were observed, maintaining the average values between the treatments and the control practically constant. For static flexion, MOR and MOE, no significant differences were observed, these properties being analyzed with ANOVA tests with significance of 5%. With this it can be concluded that the impregnation with furfuryl alcohol was effective, due to improvements in mechanical de-performance observed. Considering the potential of furfurylation employed in wood based on these results, it is suggested to do more research in this field in order to promote more information on the use of this wood treatment.
DOI: 10.6084/m9.figshare.9871007
title: Obtaining and characterization of polyacrylonitrile (PAN) copolymers for use in extruder spinning processes

description: ABSTRACT The availability of new materials, processes and equipment always brings favorable perspectives to the market. The search for alternative processes and the precursor production cost reduction of high performance materials has become essential for the development of the industrial activity to produce the general purpose carbon fiber to supply the continuously expanding domestic market. The extrusion process of PAN fibers shows potential of cost reduction as it is a precursor of carbon fibers, in relation to the wet spinning method used up to now. This innovative technology enables spinning by melting PAN using glycerin (from biodiesel production) as the primary plasticizer, dispensing the use of highly toxic solvents. Thus, the present work aimed to obtain PAN copolymers that are suitable for the conventional extrusion spinning process. Therefore, PAN copolymer was copolymerized by aqueous suspension and the characterization was performed by Gel Permeation Chromatography (GPC) analysis. The results showed that GPC technique was suitable for determining of the PAN copolymers molecular properties and that styrene monomer was suitable for polymerization, generating PAN-co-ES copolymers with Mn &gt; 40,000 g / mol and Mw &gt; 130,000 g / mol.
DOI: 10.6084/m9.figshare.9871001
title: Photodegradation of polyacrylamide hydrogel in the presence of chemical substances for use in agriculture

description: ABSTRACT Used in agriculture as a soil conditioner because the polyacrylamide basic constituent of the hydrogel has the characteristic of absorbing water by physical process and also stock for the plants according to their water requirements. However, the hydrogel has endured its chain degradation because of UV radiation and salts present in the soil causing the release of residues and toxic substances and non-biodegradable substance. This study aimed to evaluate the photodegradation of polyacrylamide and the effect of some chemical substances present in the soil in the degradation of this polymer. For the evaluation of photodegradation of polyacrylamide was performed by Fourier transform infrared spectrometry (FTIR) to demonstrate the degree of polymer degradation. It was also evaluated the water retention in soil with of the gel by the centrifuge method. The results showed that after degraded polyacrylamide decrease in the amide grouping being indicative of polyacrylamide chain breaking acrylamide. Moreover the polymer lost its water retention characteristics, with the modification of its polymeric nets and gel appearance.
DOI: 10.6084/m9.figshare.9871004
title: Mechanical Properties and Metallurgical Characterization of LM25/ZrO2 Composites Fabricated by Stir Casting Method

description: ABSTRACT Zirconia (ZrO2) dispersed aluminum alloy metal matrix composites produced by stir casting techniques. Using stir casting techniques, aluminium based composites with varying amounts of 3%, 6%, 9%, and 12% of zirconia by weight are fabricated. The prepared samples were subjected to physical, mechanical,tribiology and microstructure investigation. The extraordinary performance of Aluminium MMCs was the low density that obtained after alloying. Hardness and ductility were also increased when increase in Zirconia particle. Ultimate tensile strength, compressive strength and impact toughness were slightly increasing with the addition of zirconia particle. Microstructural characteristics shows that a homogeneous distribution of particles with reinforcement in casted composite. The investigations of the metallurgical characterization were carried using optical, scanning electron microscope, X-ray diffraction and Energy Dispersive Spectrometry (EDS) test to understand the metallurgical properties.
DOI: 10.6084/m9.figshare.9871013.v1
title: Effect of furfurylation on physical and mechanical properties of Pinus elliottii wood

description: ABSTRACT Pinus wood presents undesirable characteristics that can be attenuated with the application of treatments, in which the furfurylation is highlighted. Therefore, the objective of this work was to evaluate the effect of impregnation of furfuryl alcohol on the physical and mechanical properties of Pinus elliottii wood. For this, 4 treatments were used: control and with different loads of furfuryl alcohol (10%, 25% and 50%). The properties were determined as described in ASTM D 2395-17 (2017) and ASTM D 143-94 (2014). It was verified that, for the mechanical properties, the compression resistance parallel to the fibers, in which the MOE parameter had a significant increase for all the treatments in relation to the control group, especially for treatment (TF25%), for the MOR, higher values were obtained, but without significant differences. Regarding Janka hardness, the maximum tension in the transverse anatomical plane, higher values were observed when compared to the control, with emphasis on treatment (TF50%), which showed higher values with significant difference. For the tangential plane, no significant differences were observed, maintaining the average values between the treatments and the control practically constant. For static flexion, MOR and MOE, no significant differences were observed, these properties being analyzed with ANOVA tests with significance of 5%. With this it can be concluded that the impregnation with furfuryl alcohol was effective, due to improvements in mechanical de-performance observed. Considering the potential of furfurylation employed in wood based on these results, it is suggested to do more research in this field in order to promote more information on the use of this wood treatment.
DOI: 10.6084/m9.figshare.9871004.v1
title: Mechanical Properties and Metallurgical Characterization of LM25/ZrO2 Composites Fabricated by Stir Casting Method

description: ABSTRACT Zirconia (ZrO2) dispersed aluminum alloy metal matrix composites produced by stir casting techniques. Using stir casting techniques, aluminium based composites with varying amounts of 3%, 6%, 9%, and 12% of zirconia by weight are fabricated. The prepared samples were subjected to physical, mechanical,tribiology and microstructure investigation. The extraordinary performance of Aluminium MMCs was the low density that obtained after alloying. Hardness and ductility were also increased when increase in Zirconia particle. Ultimate tensile strength, compressive strength and impact toughness were slightly increasing with the addition of zirconia particle. Microstructural characteristics shows that a homogeneous distribution of particles with reinforcement in casted composite. The investigations of the metallurgical characterization were carried using optical, scanning electron microscope, X-ray diffraction and Energy Dispersive Spectrometry (EDS) test to understand the metallurgical properties.
DOI: 10.6084/m9.figshare.9871007.v1
title: Obtaining and characterization of polyacrylonitrile (PAN) copolymers for use in extruder spinning processes

description: ABSTRACT The availability of new materials, processes and equipment always brings favorable perspectives to the market. The search for alternative processes and the precursor production cost reduction of high performance materials has become essential for the development of the industrial activity to produce the general purpose carbon fiber to supply the continuously expanding domestic market. The extrusion process of PAN fibers shows potential of cost reduction as it is a precursor of carbon fibers, in relation to the wet spinning method used up to now. This innovative technology enables spinning by melting PAN using glycerin (from biodiesel production) as the primary plasticizer, dispensing the use of highly toxic solvents. Thus, the present work aimed to obtain PAN copolymers that are suitable for the conventional extrusion spinning process. Therefore, PAN copolymer was copolymerized by aqueous suspension and the characterization was performed by Gel Permeation Chromatography (GPC) analysis. The results showed that GPC technique was suitable for determining of the PAN copolymers molecular properties and that styrene monomer was suitable for polymerization, generating PAN-co-ES copolymers with Mn &gt; 40,000 g / mol and Mw &gt; 130,000 g / mol.
DOI: 10.6084/m9.figshare.9870995
title: Application of adsorptive process for desulphursation of fuel using coconut fiber as adsorbents

description: Abstract The development of more efficient and low-cost adsorbents to remove sulfur compounds has been improving, for instance, processes used in oil refining. Efficiency of desulfurization is correlated to the characteristics found in the adsorbent such as adsorption capacity, durability and regenerateness. This study aims to prepare coconut fiber impregnated with nickel and evaluate its adsorptive capacity of sulfur compounds such as the thiophene present in fuels. The utilized adsorbent was coconut fiber (mesocarp) obtained in the city of Quixadá, state of Ceará, and the adsorbate was thiophene in n-hexane solution. During an adsorbent characterization test it could be observed that the number of proton charges in the surface of both natural and modified fibers is a function of pH. The materials showed adsorptive capacity of 35,0 mg.g-1 of the sulfur compound. In the balance study, isotherm was best represented by the math model of Redlich-Peterson, which indicates heterogeneity in the adsorption sites. Adsorption kinetics was more adequate with the pseudo-second order model.
DOI: 10.6084/m9.figshare.9870998
title: Evaluation of the morphology and mechanical properties of laminated composites based on epoxy, cork and glass microspheres

description: ABSTRACT In this work, epoxy polymer composites laminated with cork and hollow glass microspheres were developed. The laminated composites were manually made and evaluated for the morphological characteristics of the scanning electron microscope and the influence of the incorporation of the fillers was evaluated by means of density and flexural strength. In general, good dispersion of both the cork powder and the hollow glass microspheres was observed in the central layers of the sheet, but the cork-based cores presented better adhesion to the matrix. It was also observed the reduction in the density of all the composites with respect to the pure matrix and that the flexural modulus of cork-based composites and those with hollow microspheres of glass, even with close values, were superior to modulus of bending of the pure epoxy system. Core laminates with cork incorporation may be applied as an alternative where weight reduction is required and also where there is the expectation of bending stresses higher than those supported by the pure resin.
DOI: 10.6084/m9.figshare.9871001.v1
title: Photodegradation of polyacrylamide hydrogel in the presence of chemical substances for use in agriculture

description: ABSTRACT Used in agriculture as a soil conditioner because the polyacrylamide basic constituent of the hydrogel has the characteristic of absorbing water by physical process and also stock for the plants according to their water requirements. However, the hydrogel has endured its chain degradation because of UV radiation and salts present in the soil causing the release of residues and toxic substances and non-biodegradable substance. This study aimed to evaluate the photodegradation of polyacrylamide and the effect of some chemical substances present in the soil in the degradation of this polymer. For the evaluation of photodegradation of polyacrylamide was performed by Fourier transform infrared spectrometry (FTIR) to demonstrate the degree of polymer degradation. It was also evaluated the water retention in soil with of the gel by the centrifuge method. The results showed that after degraded polyacrylamide decrease in the amide grouping being indicative of polyacrylamide chain breaking acrylamide. Moreover the polymer lost its water retention characteristics, with the modification of its polymeric nets and gel appearance.
DOI: 10.6084/m9.figshare.9870989
title: Byproducts of babassu (Orbignya sp) as new adsorptive materials: a review

description: ABSTRACT Babaçu (Orbignya sp) is a lignocellulosic plant, available in large scale in the north-northeast of Brazil, which has been emerging as a good source of biomaterials, being used in several studies as adsorbents. The objective of this study was to prospectively study the use of babaçu by-products (endocarp, mesocarp, epicarp and activated carbon) as a material with the exception of potential adsorptive target species for inorganic and organic molecules. was carried out through a literature review (article and patents), in the time period of July 2015 and February 2018. The databases used were: National Institute of Industrial Property of Brazil, World Intellectual Property Organization, Patents, Patent and Trademark Office of the United States of America and Spain for Patent Search; and Pubmed, Scopus, Web of Science and Scientific Electronic Library Online, for articles. From the careful analysis of the bibliographical survey, 18 scientific papers and 1 patent on the subject were selected. Among them, the mesocarp, epicarp (natural and modified) and the activated charcoal of babassu were very efficient adsorption substrates. The results were satisfactory, so that babassu was shown as a good indicator of cost and benefit, thus being a quality and accessible biomaterial.
DOI: 10.6084/m9.figshare.9870992
title: Sustainable blends of LDPE/NR and sugarcane bagasse ashes with PE-g-MA thermomechanical relationships

description: ABSTRACT The polymer blends obtained with residues that before were called wastes has been growing as a viable solution, allowing improvements in the mechanical properties and as sustainable alternative. This work reports the effects of blends of low-density polyethylene (LDPE) and natural rubber (NR), with sugar cane bagasse ash (SCBA) as filler, with and without polyethylene-graft-maleic anhydride (PE-g-MA) how coupling agent. The dynamic mechanical behavior and a stress-strain analysis were studied. The materials were further evaluated by differential scanning calorimetry and morphological observations. The results showed that incorporation of the PE-g-MA reduced the strain and improved the stress and the Young module of the mixtures. Moreover, the presence of SCBA increased the hardness while maintaining the tensile strength and the elongation behavior of the polymer. The results demonstrate the potential use of SCBA in the elastomer and thermoplastic mixture, free of vulcanization agents.
DOI: 10.6084/m9.figshare.9870998.v1
title: Evaluation of the morphology and mechanical properties of laminated composites based on epoxy, cork and glass microspheres

description: ABSTRACT In this work, epoxy polymer composites laminated with cork and hollow glass microspheres were developed. The laminated composites were manually made and evaluated for the morphological characteristics of the scanning electron microscope and the influence of the incorporation of the fillers was evaluated by means of density and flexural strength. In general, good dispersion of both the cork powder and the hollow glass microspheres was observed in the central layers of the sheet, but the cork-based cores presented better adhesion to the matrix. It was also observed the reduction in the density of all the composites with respect to the pure matrix and that the flexural modulus of cork-based composites and those with hollow microspheres of glass, even with close values, were superior to modulus of bending of the pure epoxy system. Core laminates with cork incorporation may be applied as an alternative where weight reduction is required and also where there is the expectation of bending stresses higher than those supported by the pure resin.
DOI: 10.6084/m9.figshare.9870983
title: Effect of itaconic and fumaric acids on the emulsion copolymerization of styrene with n-butyl acrylate to produce cementitious mortar

description: ABSTRACT Carboxylic monomers are often employed in polymer formulations obtained by emulsion or miniemulsion polymerization with the aim of improve the better latex application properties. The aim of this work was to evaluate the effect of itaconic (IA), fumaric (FA) and methacrylic (MAA) acid on the emulsion copolymerization of styrene (STy) with n-butyl acrylate (ABu), aiming to obtain stable latexes with low concentration of poly(carboxylic acid) in the aqueous phase, to be used as cement additive. Latexes of STy/ABu/AI, STy/ABu/AF and Sty/ABu/AMA were obtained and characterized in relation to solids content, particle diameter, polydispersity, viscosity, minimum film forming temperature (TMFF), freeze-thaw stability, colloidal stability and distribution of the carboxylic groups. Cementitious mortar was prepared with the latexes and evaluated. The results obtained show that the type of carboxylic acid employed affects the physicochemical properties of latexes and the interaction with the components of the mortar. Among the acids studied, methacrylic acid had a lower effect on the colloidal properties of latexes. The latex produced with fumaric acid presented low colloidal stability, high concentration of carboxylic groups in the aqueous phase and low interaction with the components of the cementitious mortar.
DOI: 10.6084/m9.figshare.9870986
title: Influence of the hydroxypropyl acrylate and hydroxypropyl methacrylate monomer concentration on the emulsion copolymerization of styrene with n-butyl acrylate and acrylonitrile to produce adhesives

description: ABSTRACT Hydroxyl acrylic monomers are important because the hydroxyl group present in the molecule can react with isocyanate groups, conferring better mechanical properties to the final polymer when applied onto some substrates. The aim of this work was to study the effects of the hydroxypropyl acrylate (HPA) and hydroxypropyl methacrylate (HPMA) monomer concentration on the emulsion polymerization of styrene (St) with n-butyl acrylate (ABu) and acrylonitrile (ACN). The goal of this work was to obtain latexes with higher concentrations of hydroxyl groups, ideal for reacting with isocyanate, without generating residues or coagulum. Latexes with different amounts of HPA and HPMA (0,3,5,7 e 10 wt%) were obtained and characterized with respect to solids content, viscosity, particle diameter, particle size distribution, freeze-thaw stability, minimum film forming temperature, coagulum formation, hardness and colloidal stability. The results show that the increased HPMA concentration affected the colloidal properties of the latexes. Among the concentrations of HPMA studied, it was possible to obtain latex with a maximum concentration of 5% HPA and 7% HPMA, whereas latex produced with 10% HPA and HPMA had low colloidal stability. Adhesives was obtained by mixing styrene-acrylic hydroxylated latex with a blocked poly(isocyanate) dispersion and characterized.