cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.14322002
title: Plasma nitriding and deposition in AISI M2 and D2 steel tools used in nail forming and stamping: a viability study

description: ABSTRACT The growing need to increase the productivity of the industrial sector, drives the development of new steels and new treatments that can improve the performance and useful life of cutting, forming and stamping tools. Plasma-assisted surface treatments stand out in this context. Previous research has shown that these coatings are efficient in increasing hardness, wear resistance and corrosion resistance of different types of steels. In this sense, samples and tools from AISI M2 and D2 heat-treated steels were subjected to conventional plasma nitriding processes, in cathodic cage and duplex treatment in order to evaluate the effect of these treatments on forming tools seeking the viability of applying the method in the industrial sector with the reduction of the manufacturing cost in the conformation and stamping of nails. Vickers microhardness tests, SEM analysis and X-Ray Diffraction (XRD) made it possible to identify mechanical properties, layer of compounds and the phases present, respectively. The performance of the tools was based on the volume of nails produced in kg. The productive cost was determined in function of productivity, the purchase price of the tool and the nitriding price. The use of plasma nitriding proved to be feasible for both steels, highlighting the fact that the D2 steel tools nitrided at 480ºC for 3 hours, obtained the greatest productivity gains in relation to non-nitrided tool. The application of conventional nitriding in the steel tool M2 at 480ºC for 4 hours made it possible to reduce its cost by 26% and reduce by 3.5% the total cost of producing nails, obtaining the best cost-benefit ratio.
DOI: 10.6084/m9.figshare.14268549
title: Evaluation of the potentials of jurema preta (Mimosa tenuiflora) and cajueiro (Anacardium occidentale L.) extracts for use in antimicrobials and antioxidants active packaging

description: ABSTRACT Packaging has the basic function of protecting the food and ensuring its commercial integrity. They can be produced from biodegradable materials with specific functionalities such as antimicrobial and antioxidant action. In addition, research has been carried out to replace synthetic additives with natural additives, such as plant extracts, due to the chemical compounds present in their mixtures. Poly (butylene adipate co-terephthalate) - (PBAT) has been extensively studied as a possible replacement for conventional polymers due to its biodegradability. Thus, the objective of this work was to evaluate the potentialities of jurema preta (Mimosa tenuiflora) and cajueiro (Anacardium occidentale Linn) plant extracts in order to apply them as additives in PBAT packages with antioxidant and antimicrobial active properties. The extracts were obtained by the Sohxlet extraction technique at three different times, 4, 6 and 8 hours, with the best yield at 6 hours for jurema preta and 4 hours for cajueiro. In the flavonoid presence test the jurema preta extract presented higher concentration and in the total phenolics test, using the Folin-Ciocalteau method, the cashew tree obtained the highest concentration. Both extracts showed significant antioxidant capacities by the two methods, phosphomolybdenum and DPPH. Cashew tree presented better inhibition halo against Staphylococcus aureus, and therefore its minimum inhibitory concentration (MIC) was determined, 0.0170 g.mL-1. This extract was incorporated into the PBAT for the ethanolic migration test, by means of which a kinetic model was determined and it was observed that the migration rate, 0.0167 ?g.mL-1.min-1, was reduced by about a day, indicating good extract potential for these types of packaging.
DOI: 10.6084/m9.figshare.14268549.v1
title: Evaluation of the potentials of jurema preta (Mimosa tenuiflora) and cajueiro (Anacardium occidentale L.) extracts for use in antimicrobials and antioxidants active packaging

description: ABSTRACT Packaging has the basic function of protecting the food and ensuring its commercial integrity. They can be produced from biodegradable materials with specific functionalities such as antimicrobial and antioxidant action. In addition, research has been carried out to replace synthetic additives with natural additives, such as plant extracts, due to the chemical compounds present in their mixtures. Poly (butylene adipate co-terephthalate) - (PBAT) has been extensively studied as a possible replacement for conventional polymers due to its biodegradability. Thus, the objective of this work was to evaluate the potentialities of jurema preta (Mimosa tenuiflora) and cajueiro (Anacardium occidentale Linn) plant extracts in order to apply them as additives in PBAT packages with antioxidant and antimicrobial active properties. The extracts were obtained by the Sohxlet extraction technique at three different times, 4, 6 and 8 hours, with the best yield at 6 hours for jurema preta and 4 hours for cajueiro. In the flavonoid presence test the jurema preta extract presented higher concentration and in the total phenolics test, using the Folin-Ciocalteau method, the cashew tree obtained the highest concentration. Both extracts showed significant antioxidant capacities by the two methods, phosphomolybdenum and DPPH. Cashew tree presented better inhibition halo against Staphylococcus aureus, and therefore its minimum inhibitory concentration (MIC) was determined, 0.0170 g.mL-1. This extract was incorporated into the PBAT for the ethanolic migration test, by means of which a kinetic model was determined and it was observed that the migration rate, 0.0167 ?g.mL-1.min-1, was reduced by about a day, indicating good extract potential for these types of packaging.
DOI: 10.6084/m9.figshare.14268555.v1
title: Workability maintenance of water-reducing admixtures in high-performance pastes produced with different types of Portland cement

description: ABSTRACT This work evaluated the efficiency and workability manteinance of a polyfunctional (lignosulfonate-based) and a superplasticizer (polycarboxylate-based) admixture in high-performance pastes (water/cement ratios of 0.30, 0.33 and 0.36) produced with two types of Portland cement (one pozzolanic and one high early strength). The workability of the pastes was evaluated by the mini slump test immediately after mixing, and after 20 and 40 minutes. Furthermore, the mechanical strength of pastes with fixed w/c ratio (0.36) and mini slump (130 mm), produced with the different combinations of cements and admixtures, was evaluated. The results showed that the CP IV+lignosulfonate and CP V-ARI+polycarboxylate mixes presented the best workability maintenance over time. The pastes produced with CP V-ARI presented 28-day strengths about 22% higher than those produced with CP IV, for both admixtures. In turn, the lignosulfonate-containing pastes showed strengths about 10% higher than those produced with the polycarboxylate-based admixture. Overall, it was possible to obtain the same workability for high-performance Portland cement pastes produced with both admixtures and cements; however, the workability mantainance and mechanical strength highly depends on the combination of cement and admixture used.
DOI: 10.6084/m9.figshare.14268555
title: Workability maintenance of water-reducing admixtures in high-performance pastes produced with different types of Portland cement

description: ABSTRACT This work evaluated the efficiency and workability manteinance of a polyfunctional (lignosulfonate-based) and a superplasticizer (polycarboxylate-based) admixture in high-performance pastes (water/cement ratios of 0.30, 0.33 and 0.36) produced with two types of Portland cement (one pozzolanic and one high early strength). The workability of the pastes was evaluated by the mini slump test immediately after mixing, and after 20 and 40 minutes. Furthermore, the mechanical strength of pastes with fixed w/c ratio (0.36) and mini slump (130 mm), produced with the different combinations of cements and admixtures, was evaluated. The results showed that the CP IV+lignosulfonate and CP V-ARI+polycarboxylate mixes presented the best workability maintenance over time. The pastes produced with CP V-ARI presented 28-day strengths about 22% higher than those produced with CP IV, for both admixtures. In turn, the lignosulfonate-containing pastes showed strengths about 10% higher than those produced with the polycarboxylate-based admixture. Overall, it was possible to obtain the same workability for high-performance Portland cement pastes produced with both admixtures and cements; however, the workability mantainance and mechanical strength highly depends on the combination of cement and admixture used.
DOI: 10.6084/m9.figshare.14322005
title: Evaluation and characterization of edible carboxymethylcellulose biofilm containing chitosan nanoparticles and turmeric

description: ABSTRACT The production of biofilms and polymeric coatings based on natural polymers in order to apply them as food packaging is constantly being researched due to the need to decrease the volume of discarded plastic packaging and optimize the properties and validity of food. Among the immense variety of polymers used for this purpose, carboxymethylcellulose (CMC) has stood out for presenting favorable characteristics for the filmogenic solutions formation, besides being biodegradable and presenting low cost. Aiming to enhance the natural properties of this polymer, researchers have used additives that are incorporated into the filmogenic solution such as chitosan nanoparticles (NSQ) and turmeric. Chitosan is also a natural polymer, widely used in applications in the fields of pharmacology, biomaterials technology, biomedicine, agriculture and the cosmetics and food industries. Turmeric derived from saffron, has antioxidant and antimicrobial properties, which has aroused a lot of interest, especially in the food industry, aiming to replace synthetic antioxidants with these natural materials. In this work, chitosan nanoparticles were prepared by ionotropic gelation and incorporated into the polymer (CMC), along with turmeric, in order to reinforce and enhance the natural properties of this polymer for the preparation of edible biofilms. After preparation, they are characterized by analysis of mechanical properties, water vapor permeability and contact angle.
DOI: 10.6084/m9.figshare.14322005.v1
title: Evaluation and characterization of edible carboxymethylcellulose biofilm containing chitosan nanoparticles and turmeric

description: ABSTRACT The production of biofilms and polymeric coatings based on natural polymers in order to apply them as food packaging is constantly being researched due to the need to decrease the volume of discarded plastic packaging and optimize the properties and validity of food. Among the immense variety of polymers used for this purpose, carboxymethylcellulose (CMC) has stood out for presenting favorable characteristics for the filmogenic solutions formation, besides being biodegradable and presenting low cost. Aiming to enhance the natural properties of this polymer, researchers have used additives that are incorporated into the filmogenic solution such as chitosan nanoparticles (NSQ) and turmeric. Chitosan is also a natural polymer, widely used in applications in the fields of pharmacology, biomaterials technology, biomedicine, agriculture and the cosmetics and food industries. Turmeric derived from saffron, has antioxidant and antimicrobial properties, which has aroused a lot of interest, especially in the food industry, aiming to replace synthetic antioxidants with these natural materials. In this work, chitosan nanoparticles were prepared by ionotropic gelation and incorporated into the polymer (CMC), along with turmeric, in order to reinforce and enhance the natural properties of this polymer for the preparation of edible biofilms. After preparation, they are characterized by analysis of mechanical properties, water vapor permeability and contact angle.
DOI: 10.6084/m9.figshare.14322008
title: Microstructural characteristics of concrete added with C-S-H and carbon nanotubes

description: ABSTRACT The incorporation of nanomaterials is a possibility for the improvement and modification of characteristics or properties in materials. The incorporation of nanomaterials is a possibility for the improvement or even the creation of some characteristics or properties in materials. The use of carbon nanotubes (CNT) has been researched in concretes to increase the compressive and flexural strength, modulus of elasticity among other characteristics such as reduced permeability. The aim was to improve the hydration kinetics of cement silicates by creating nucleation spaces and growth of crystalline structures making the microstructure denser, as verified by microscopic analysis and porosimetry. Microconcrete specimens had tensile strength tested at 28 days. The percentages of NTC (0.0% and 0.2%) and C-S-H (0.0% and 2.0%) were varied, as well as the Ca/Si ratio (0.8 and 1.2) of C-S-H. In total, 5 types of composites were produced, and their results were compared to the reference material (without additions). The composite C2-0.8 (with 2% C-S-H of Ca/ Si =0.8) presented tensile strength 18.0% higher than the reference material (R), already for the composite CT2-0, 8 (2% C-S-H Ca / Si = 0.8 and 2% CNT) the increase in resistance of 33% compared to the reference. The composite T2 (added only 0.2% of CNT) presented 13% of increase of resistance when compared to material R. The use of NTC, in concrete or other cementitious mixtures, can be enhanced if used in conjunction with C-S-H (precipitate). This improves the hydration of cement silicates by creating nucleation spaces that favor crystalline growth and reduce porosity as seen in electron microscopy analysis and mercury intrusion porosimetry tests performed on the samples.
DOI: 10.6084/m9.figshare.14322008.v1
title: Microstructural characteristics of concrete added with C-S-H and carbon nanotubes

description: ABSTRACT The incorporation of nanomaterials is a possibility for the improvement and modification of characteristics or properties in materials. The incorporation of nanomaterials is a possibility for the improvement or even the creation of some characteristics or properties in materials. The use of carbon nanotubes (CNT) has been researched in concretes to increase the compressive and flexural strength, modulus of elasticity among other characteristics such as reduced permeability. The aim was to improve the hydration kinetics of cement silicates by creating nucleation spaces and growth of crystalline structures making the microstructure denser, as verified by microscopic analysis and porosimetry. Microconcrete specimens had tensile strength tested at 28 days. The percentages of NTC (0.0% and 0.2%) and C-S-H (0.0% and 2.0%) were varied, as well as the Ca/Si ratio (0.8 and 1.2) of C-S-H. In total, 5 types of composites were produced, and their results were compared to the reference material (without additions). The composite C2-0.8 (with 2% C-S-H of Ca/ Si =0.8) presented tensile strength 18.0% higher than the reference material (R), already for the composite CT2-0, 8 (2% C-S-H Ca / Si = 0.8 and 2% CNT) the increase in resistance of 33% compared to the reference. The composite T2 (added only 0.2% of CNT) presented 13% of increase of resistance when compared to material R. The use of NTC, in concrete or other cementitious mixtures, can be enhanced if used in conjunction with C-S-H (precipitate). This improves the hydration of cement silicates by creating nucleation spaces that favor crystalline growth and reduce porosity as seen in electron microscopy analysis and mercury intrusion porosimetry tests performed on the samples.
DOI: 10.6084/m9.figshare.14322009
title: Tribological Properties of Fly Ash Blended Polymer Composites

description: ABSTRACT In this study, it was studied that the abrasion resistance and characteristics of polymer composites with fly ash (FA). The epoxy based polymer composites are produced with resin and FA as mineral additive. Mixtures of different ratio by replacing the FA were added to the resin from 0 to 30% by weight. Polymeric samples were cured in air conditioning and they were taken from the molds after 24 hours. Polymeric samples gain ultimate strength after 7 days. Therefore, abrasion tests were performed on 7 aged specimens. Abrasion characteristics of polymer composites were defined by pin-on-disc test for 500 m under a dry friction condition and room temperature. Three types of loading conditions were carried out as 5, 10, 15 and 30 N. The hardness and wear resistance values increased with the increase in the content of fly ash. Showing the relationship between wear rate and hardness, an equation with parameters dependent on load was provided. There was an increase in the friction coefficient with an increase in the surface roughness values. In addition, dynamic friction was as a function of the wear rate. The wear surfaces of the polymer composites were analyzed using scanning electron microscopy. It was observed that the wear rate of the polymer composites and pure epoxy samples ranged from 17.82 to 172.96 mm3/Nm.
DOI: 10.6084/m9.figshare.14322009.v1
title: Tribological Properties of Fly Ash Blended Polymer Composites

description: ABSTRACT In this study, it was studied that the abrasion resistance and characteristics of polymer composites with fly ash (FA). The epoxy based polymer composites are produced with resin and FA as mineral additive. Mixtures of different ratio by replacing the FA were added to the resin from 0 to 30% by weight. Polymeric samples were cured in air conditioning and they were taken from the molds after 24 hours. Polymeric samples gain ultimate strength after 7 days. Therefore, abrasion tests were performed on 7 aged specimens. Abrasion characteristics of polymer composites were defined by pin-on-disc test for 500 m under a dry friction condition and room temperature. Three types of loading conditions were carried out as 5, 10, 15 and 30 N. The hardness and wear resistance values increased with the increase in the content of fly ash. Showing the relationship between wear rate and hardness, an equation with parameters dependent on load was provided. There was an increase in the friction coefficient with an increase in the surface roughness values. In addition, dynamic friction was as a function of the wear rate. The wear surfaces of the polymer composites were analyzed using scanning electron microscopy. It was observed that the wear rate of the polymer composites and pure epoxy samples ranged from 17.82 to 172.96 mm3/Nm.
DOI: 10.6084/m9.figshare.14322011
title: Analysis of a steam generator using the FMEA and FTA techniques

description: ABSTRACT The structural health of a steam generator can be affected by several factors, such as the type of material of the structure, the quality of weld joints made, the boiler manufacturing parameters and the operating procedures performed. In this context, corrosion stands out as one of the major sources of degradation and can lead a surface under pressure to complete collapse. In this study, a failure analysis was made to investigate the process that lead to rupture and corrosion in a steam generator, using FMEA (Failure Mode and Effects Analysis) and FTA (Fault Tree Analysis) techniques. Metallographic tests of structure and a physicochemical study of the system feed water were also analysed. The metallographic tests showed small cracks in the base metal, in addition to lack of penetration in the welded joint and a misalignment of the joint. Water analysis showed a high concentration of chloride ions and a low pH of the feedwater, factors that cause the rupture of the passive layer and result in corrosion. The FMEA and FTA techniques allowed the understanding of the factors that act as stress concentrators, associated with lower quality of the steam generator feed water and errors during the welding process, which resulted in localized corrosion followed by rupture and leakage of liquid and steam water.
DOI: 10.6084/m9.figshare.14322012
title: Combustion synthesis and characterization of Ni-doped LiMn2O4 cathode nanoparticles for lithium ion battery applications

description: ABSTRACT In this research work, fine powders of spinel-type LiMn2-xNixO4-?(where x = 0.1, 0.2, 0.3, 0.4 and 0.5) as cathode materials for lithium ion batteries were synthesized by combustion synthesis using urea as fuel and metal nitrates as oxidizers at a temperature of 600°C. The physiochemical properties of the prepared cathode materials were investigated by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), particle size analysis, energy dispersive analysis (EDAX) and scanning electron microscopy (SEM). The electrochemical characteristics were studied by impedance spectroscopy. It was found that the physical charactetertistics were moderately influenced because of different dopant (Ni) concentration. Among the samples studied, LiMn1.9Ni0.1O4-? resulted in better electrical conductivity (6.49 x 10-5 Scm-1) at room temperature and hence it may be suitable for lithium ion battery applications.
DOI: 10.6084/m9.figshare.14322012.v1
title: Combustion synthesis and characterization of Ni-doped LiMn2O4 cathode nanoparticles for lithium ion battery applications

description: ABSTRACT In this research work, fine powders of spinel-type LiMn2-xNixO4-?(where x = 0.1, 0.2, 0.3, 0.4 and 0.5) as cathode materials for lithium ion batteries were synthesized by combustion synthesis using urea as fuel and metal nitrates as oxidizers at a temperature of 600°C. The physiochemical properties of the prepared cathode materials were investigated by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), particle size analysis, energy dispersive analysis (EDAX) and scanning electron microscopy (SEM). The electrochemical characteristics were studied by impedance spectroscopy. It was found that the physical charactetertistics were moderately influenced because of different dopant (Ni) concentration. Among the samples studied, LiMn1.9Ni0.1O4-? resulted in better electrical conductivity (6.49 x 10-5 Scm-1) at room temperature and hence it may be suitable for lithium ion battery applications.
DOI: 10.6084/m9.figshare.14268598
title: Ti-25Nb-25Ta alloy treated by plasma electrolytic oxidation in phosphoric acid for implant applications

description: ABSTRACT Among titanium alloys with non-toxic elements, the Ti-25Nb-25Ta alloy has good elastic behavior for applications in osseous implants, biocompatibility, and excellent corrosion resistance. The present study aimed to better the biocompatibility characteristics of Ti-25Nb-25Ta alloy modifying its surface through Plasma Electrolytic Oxidation (PEO) treatment. The formed oxide coating is amorphous and composed of two distinct porous formations: smaller hole-shaped pores and larger volcano-like pores. The regions with the formation of smaller pores and in the hole shaped presented the highest atomic percentage of the chemical element phosphorus. Nanoindentation tests have shown that the hardness of the Ti-25Nb-25Ta alloy is slightly lower than the commercially pure grade 2 titanium (a material used as reference), while elastic modulus measurements of Ti-25Nb-25Ta presented more suitable values for implant application (lower values when compared with titanium reference). After PEO treatment there were significant mechanical surface improvements (increased fairly surface hardness and decreased elastic modulus) for application in osseous tissue. Despite the Ti-25Nb-25Ta alloy presented excellent characteristics for applications in hard biological tissues, the PEO treatment better its features.