cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.14321763
title: Mathematical model of a combustion chamber of a pirotubular boiler using the matlab-simulink tool

description: ABSTRACT This article presents the implementation of the mathematical model of the combustion chamber of a pyro-tubular boiler, by means of the approach of mass, energy and stoichiometric balances. These balances were described by the input components (air and fuel) that are presented in the combustion zone, based on the concept of maintaining the stoichiometric relationship between them, which were simulated through the computational tools such as the ESS and Matlab®, in order to determine the behavior of combustion gases depending on the type of chemical reaction presented. Likewise, it was determined the amount of carbons and hydrogens that make up the study fuels (ACMP and kerosene), as well as the kmol / s that compose the air, with the objective of analyzing its oxidation and determining the production of [CO]_(2,) H_2 O. Finally, the respective comparison was made analyzing the values of pressure and temperature in the three types of combustion, stoichiometric, with presence of unburned and with excess air. The approach of the mathematical model was applied for the two types of study fuels.
DOI: 10.6084/m9.figshare.14321767.v1
title: High temperature corrosion of stainless steel AISI 316L in molten nitrate salts based thermofluids for concentration solar plants

description: ABSTRACT With the recent boom of environmentally friendly energies, the demand for materials capable of resisting certain working conditions demanded by these processes arises, for example, the obtaining of energy from sunlight, in which the Thermal storage is vital during the operation of the plant. In the present work, the reaction of AISI 316L steel in contact with molten nitrate salts (Ca (NO3)2 + NaNO3 + KNO3 and LiNO3 + KNO3 + NaNO3) was evaluated, gravimetric tests were carried out with Two types of ternary salts of nitrates at a temperature of 600°C, evaluating the gain of mass in the steel, in turn, were carried out metallographic studies, in order to evaluate the damage of the microstructure. By means of SEM and optical micrographs, the morphology of the layer and the damage caused to the steel was observed. The surface where the greater aggressiveness of damage by the ternary salt in the steel was evidenced is the surface of the steel exposed to the lithium salt. The results of DRX yielded Fe0.612Ni0.388 and CrNi, as the main steel corrosion products, demonstrating that the salt fused with the calcium component is less harmful to the steel used in this project.
DOI: 10.6084/m9.figshare.14321767
title: High temperature corrosion of stainless steel AISI 316L in molten nitrate salts based thermofluids for concentration solar plants

description: ABSTRACT With the recent boom of environmentally friendly energies, the demand for materials capable of resisting certain working conditions demanded by these processes arises, for example, the obtaining of energy from sunlight, in which the Thermal storage is vital during the operation of the plant. In the present work, the reaction of AISI 316L steel in contact with molten nitrate salts (Ca (NO3)2 + NaNO3 + KNO3 and LiNO3 + KNO3 + NaNO3) was evaluated, gravimetric tests were carried out with Two types of ternary salts of nitrates at a temperature of 600°C, evaluating the gain of mass in the steel, in turn, were carried out metallographic studies, in order to evaluate the damage of the microstructure. By means of SEM and optical micrographs, the morphology of the layer and the damage caused to the steel was observed. The surface where the greater aggressiveness of damage by the ternary salt in the steel was evidenced is the surface of the steel exposed to the lithium salt. The results of DRX yielded Fe0.612Ni0.388 and CrNi, as the main steel corrosion products, demonstrating that the salt fused with the calcium component is less harmful to the steel used in this project.
DOI: 10.6084/m9.figshare.14321769.v1
title: Coprocessing of tailings of the Garimpo Areinha (Diamantina/MG) for red ceramics production

description: ABSTRACT The mineral extractive industry is responsible for the production of large-scale waste which, when discarded incorrectly, can cause damage to nature and public health. Knowing this, the feasibility of the addition of tailings was studied in the production of red ceramics, seeking a sustainable alternative for the use and disposal of these wastes. The residue used for the work was extracted from three holding basins in the region of the Areinha gold mining, in Diamantina-MG, and is a mud composed of silicates and some heavy metals. The objective of this study was to manufacture structural test specimens with addition of these tailings and to evaluate their technological properties, such as: linear retraction, loss on ignition, color study, water absorption, apparent porosity and compressive strength. In comparison to the test specimens produced with pure soil, the results pointed out important improvements in these properties with addition of the tailings, reducing the water absorption and increasing the compressive strength, pointing out the viability of its use for the incorporation of the mining tailings and stabilization of heavy metals.
DOI: 10.6084/m9.figshare.14321769
title: Coprocessing of tailings of the Garimpo Areinha (Diamantina/MG) for red ceramics production

description: ABSTRACT The mineral extractive industry is responsible for the production of large-scale waste which, when discarded incorrectly, can cause damage to nature and public health. Knowing this, the feasibility of the addition of tailings was studied in the production of red ceramics, seeking a sustainable alternative for the use and disposal of these wastes. The residue used for the work was extracted from three holding basins in the region of the Areinha gold mining, in Diamantina-MG, and is a mud composed of silicates and some heavy metals. The objective of this study was to manufacture structural test specimens with addition of these tailings and to evaluate their technological properties, such as: linear retraction, loss on ignition, color study, water absorption, apparent porosity and compressive strength. In comparison to the test specimens produced with pure soil, the results pointed out important improvements in these properties with addition of the tailings, reducing the water absorption and increasing the compressive strength, pointing out the viability of its use for the incorporation of the mining tailings and stabilization of heavy metals.
DOI: 10.6084/m9.figshare.14321772
title: Evaluation of thermochemical and physicomechanical properties of three fast growing forest species

description: ABSTRACT The woods have distinct technological properties, as they are organic and heterogeneous material, requiring an assessment for proper use. Therefore, the objective of this work was the evaluation of technological properties, which are: basic density, apparent density at 12%, equilibrium moisture content, static flexion (MOE and MOR), parallel compression of the fibers (Fc and Ec), colorimetric analysis, thermogravimetry (TGA and DTG) and Fourier transform infrared spectroscopy (FT-IR), of the species of Corymbia maculata, Eucalyptus grandis, Pinus elliottii. The technological properties were determined as described in the ASTM D 2395-17 (2017) and ASTM D 143-94 (2014) standards. Regarding the physical-mechanical properties, the species showed significant differences based on statistical analysis, highlighting the species of Corymbia maculata. Regarding the colorimetric analysis, it was found that the species Corymbia maculata has a reddish-brown color, the Pinus elliottii species loves it with a light shade, while the Eucalyptus grandis reddish with a light shade. For FT-IR, similar peaks were found between species, but with different intensities, these being related to the molecular vibrations characteristic of the organic components of wood. Through thermogravimetric analysis, it can be seen that the species of Pinus elliottii and Corymbia maculata, presented greater thermal stability when compared to Eucalyptus grandis, having a lower percentage of mass loss and a delay in temperature in relation to the maximum peak of degradation ( DTG), close to 400 ° C, and these properties were analyzed with ANOVA tests with 5% significance. Thus, there is a heterogeneity among the species evaluated in this study, both from a physical, mechanical, thermal and chemical point of view, making it necessary to characterize these properties for the correct use of these materials.
DOI: 10.6084/m9.figshare.14321773.v1
title: Analysis of the performance of road subgrades using concepts of Pavement Mechanics

description: ABSTRACT The pavement is considered a system of multiple finite layers, subject to tensions, deformations and displacements from cyclical traffic demands. The foundation of the structure must have support capacity compatible with the intensity and frequency with which it will be requested. From this perspective, the present study evaluates the performance of four soils with different geological origins, usually found in road subgrades in the state of Rio Grande do Sul, based on the principles of Pavement Mechanics. The methodology applied in this study consisted of numerical simulations assisted by two computational programs: AEMC/SisPav and AASHTOWare Pavement ME Design. The mechanistic analyzes were performed to evaluate the soil response to resilient deformation and shear strength, important properties in the use of paving soils. The results showed that the resilient deformation has a preponderant role in the performance of the materials, since, for the analyzed soils, there is no evidence of shear rupture, both as a road subgrade material and as a foundation of low traffic pavements. This, however, does not rule out the hypothesis of high plastic deformations. Regarding the resilient deformation, it was also observed the inefficiency of the current flexible pavement design method, which does not consider the resilience modulus of the paving materials, resulting in the predominance of fatigue rupture, with the exception of the CB soil, which could lead to pavement to rupture by excessive wheel track rutting.
DOI: 10.6084/m9.figshare.14321773
title: Analysis of the performance of road subgrades using concepts of Pavement Mechanics

description: ABSTRACT The pavement is considered a system of multiple finite layers, subject to tensions, deformations and displacements from cyclical traffic demands. The foundation of the structure must have support capacity compatible with the intensity and frequency with which it will be requested. From this perspective, the present study evaluates the performance of four soils with different geological origins, usually found in road subgrades in the state of Rio Grande do Sul, based on the principles of Pavement Mechanics. The methodology applied in this study consisted of numerical simulations assisted by two computational programs: AEMC/SisPav and AASHTOWare Pavement ME Design. The mechanistic analyzes were performed to evaluate the soil response to resilient deformation and shear strength, important properties in the use of paving soils. The results showed that the resilient deformation has a preponderant role in the performance of the materials, since, for the analyzed soils, there is no evidence of shear rupture, both as a road subgrade material and as a foundation of low traffic pavements. This, however, does not rule out the hypothesis of high plastic deformations. Regarding the resilient deformation, it was also observed the inefficiency of the current flexible pavement design method, which does not consider the resilience modulus of the paving materials, resulting in the predominance of fatigue rupture, with the exception of the CB soil, which could lead to pavement to rupture by excessive wheel track rutting.
DOI: 10.6084/m9.figshare.14321779
title: Preliminary studies on the interesterification of soybean oil with methyl acetate catalyed by layered materials”

description: ABSTRACT The partial replacement of diesel oil with biodiesel has contributed to the increased availability of glycerin on the world market. About 10 m3 of glycerol is obtained for every 100 m3 of triacylglycerides (main component of vegetable oils and animal fats) processed in the main technological route for biodiesel production, the alkaline transesterification in homogeneous medium. Of course, the glycerin obtained as a coproduct in the process needs to be harnessed in complementary processes. This is usually possible after the glycerin undergoes several purification processes. With the intention of avoiding such complementary processes, we are proposing the synthesis of biodiesel by interesterification of soybean oil with methyl acetate, a technological route that makes it possible to obtain glycerol in the form of triacetin, that is, already chemically modified. The catalysts used in the process were the layered double hydroxide (HDL) Zn2 Al/NO3 and the commercial zinc stearate (EZ), a layered carboxylate. Both these layered materials had not yet been tested as catalysts in interesterification reactions. Conversions were obtained in fatty acid methyl esters of 50.8 ± 4.2% and 82.9 ± 1.0% (m m-1) using the EZ and HDL catalysts, respectively; when reactions were conducted using 5% catalyst (m m-1), for 10 h reaction and molar ratio methyl acetate: soybean oil of 24:1.
DOI: 10.6084/m9.figshare.14321779.v1
title: Preliminary studies on the interesterification of soybean oil with methyl acetate catalyed by layered materials”

description: ABSTRACT The partial replacement of diesel oil with biodiesel has contributed to the increased availability of glycerin on the world market. About 10 m3 of glycerol is obtained for every 100 m3 of triacylglycerides (main component of vegetable oils and animal fats) processed in the main technological route for biodiesel production, the alkaline transesterification in homogeneous medium. Of course, the glycerin obtained as a coproduct in the process needs to be harnessed in complementary processes. This is usually possible after the glycerin undergoes several purification processes. With the intention of avoiding such complementary processes, we are proposing the synthesis of biodiesel by interesterification of soybean oil with methyl acetate, a technological route that makes it possible to obtain glycerol in the form of triacetin, that is, already chemically modified. The catalysts used in the process were the layered double hydroxide (HDL) Zn2 Al/NO3 and the commercial zinc stearate (EZ), a layered carboxylate. Both these layered materials had not yet been tested as catalysts in interesterification reactions. Conversions were obtained in fatty acid methyl esters of 50.8 ± 4.2% and 82.9 ± 1.0% (m m-1) using the EZ and HDL catalysts, respectively; when reactions were conducted using 5% catalyst (m m-1), for 10 h reaction and molar ratio methyl acetate: soybean oil of 24:1.
DOI: 10.6084/m9.figshare.14321781.v1
title: Utilization of carbon nanotubes in hydrogen electrosynthesis from tropical fruit fermentation

description: ABSTRACT The use of fossil fuels, especially oil and gas, has accelerated in recent years, resulting in the global energy crisis. The fermentative biological process is a sustainable way to produce hydrogen, as it can use as a substrate various types of carbohydrate-rich industrial and household waste such as fruit, minimizing but not completely eliminating the problems caused by improper disposal of this material. From a perspective of energy conservation and use of renewable sources for energy generation, this work aims to contribute to the identification of the use of a currently unused portion of energy, optimizing hydrogen production from a fuel cell. microbial. The main nanomaterial used in electrolysis was carbon nanotubes (CNT) incorporated into carbon felt (CF). Cyclic voltammetry studies were also performed on three electrode systems: vitreous carbon electrode as working electrode, platinum electrode as auxiliary electrode and Ag / AgCl / Cl- as reference electrode. An electrochemical cell formed by two separate compartments was constructed. Before starting the electrolysis experiment, an experimental design was performed using the complete factorial design technique to analyze the influence of the variables selected for this study. The independent variables selected were: Tropical fruit liquor concentration in %v/v, type of working electrode, electrolysis time and pH of the electrolyte medium. The observed variable was the concentration in% v / v of the hydrogen gas obtained in the electrolysis. After the results of the tests, it was concluded that carbon nanotubes can be used as working electrode, presenting success in the hydrogen production process and that the pH of the electrolytic medium has a strong influence on this process. The present work was concluded presenting an alternative way in the production of a renewable energy source.
DOI: 10.6084/m9.figshare.14321781
title: Utilization of carbon nanotubes in hydrogen electrosynthesis from tropical fruit fermentation

description: ABSTRACT The use of fossil fuels, especially oil and gas, has accelerated in recent years, resulting in the global energy crisis. The fermentative biological process is a sustainable way to produce hydrogen, as it can use as a substrate various types of carbohydrate-rich industrial and household waste such as fruit, minimizing but not completely eliminating the problems caused by improper disposal of this material. From a perspective of energy conservation and use of renewable sources for energy generation, this work aims to contribute to the identification of the use of a currently unused portion of energy, optimizing hydrogen production from a fuel cell. microbial. The main nanomaterial used in electrolysis was carbon nanotubes (CNT) incorporated into carbon felt (CF). Cyclic voltammetry studies were also performed on three electrode systems: vitreous carbon electrode as working electrode, platinum electrode as auxiliary electrode and Ag / AgCl / Cl- as reference electrode. An electrochemical cell formed by two separate compartments was constructed. Before starting the electrolysis experiment, an experimental design was performed using the complete factorial design technique to analyze the influence of the variables selected for this study. The independent variables selected were: Tropical fruit liquor concentration in %v/v, type of working electrode, electrolysis time and pH of the electrolyte medium. The observed variable was the concentration in% v / v of the hydrogen gas obtained in the electrolysis. After the results of the tests, it was concluded that carbon nanotubes can be used as working electrode, presenting success in the hydrogen production process and that the pH of the electrolytic medium has a strong influence on this process. The present work was concluded presenting an alternative way in the production of a renewable energy source.
DOI: 10.6084/m9.figshare.14321784
title: Obtaining the effective elastic constants under dynamic condition of hybrid laminate for aeronautical use

description: ABSTRACT This paper deals with the determination of the effective elastic constants of structural composite materials of aeronautical use by means of vibration test. The experiment was conducted in an appropriate apparatus with a laser interferometer. Initially, a free-vibration mode vibration test was performed to obtain the natural frequencies intrinsic to the hybrid composite plate (aeronautical aluminum lamina’s alternating to carbon fiber/epoxy fabric lamina’s) known as CARALL. Likewise, aluminum 2024 T3 which is a metallic alloy that can be applied in aircraft was verified by means of this method. Both the aeronautical aluminum and the hybrid composite were modeled in a computer application (ANSYS) where, through the finite element method, frequencies related to the first six modes of vibration were obtained. The aeronautical aluminum presented a greater precision between the materials analyzed in relation to their natural frequencies. Regarding the elastic constants, the 2024 T3 aluminum alloy presented an E1 modulus of 71.3 GPa and a Poisson’s ratio of 0.31. The CARALL elastic constants were determined as the solution of a computational optimization problem described in its own language contained in an ANSYS subroutine. It was observed that the main modulus of elasticity and Poisson’s coefficient are close to the values found numerically by the mixing rule (70 GPa and 0.3, respectively).
DOI: 10.6084/m9.figshare.14321784.v1
title: Obtaining the effective elastic constants under dynamic condition of hybrid laminate for aeronautical use

description: ABSTRACT This paper deals with the determination of the effective elastic constants of structural composite materials of aeronautical use by means of vibration test. The experiment was conducted in an appropriate apparatus with a laser interferometer. Initially, a free-vibration mode vibration test was performed to obtain the natural frequencies intrinsic to the hybrid composite plate (aeronautical aluminum lamina’s alternating to carbon fiber/epoxy fabric lamina’s) known as CARALL. Likewise, aluminum 2024 T3 which is a metallic alloy that can be applied in aircraft was verified by means of this method. Both the aeronautical aluminum and the hybrid composite were modeled in a computer application (ANSYS) where, through the finite element method, frequencies related to the first six modes of vibration were obtained. The aeronautical aluminum presented a greater precision between the materials analyzed in relation to their natural frequencies. Regarding the elastic constants, the 2024 T3 aluminum alloy presented an E1 modulus of 71.3 GPa and a Poisson’s ratio of 0.31. The CARALL elastic constants were determined as the solution of a computational optimization problem described in its own language contained in an ANSYS subroutine. It was observed that the main modulus of elasticity and Poisson’s coefficient are close to the values found numerically by the mixing rule (70 GPa and 0.3, respectively).
DOI: 10.6084/m9.figshare.14321785
title: Polyester/paper composites: study of manufacturing techniques for product development

description: ABSTRACT Composite materials using vegetal fibers and industrial waste are being applied in different areas and structures, requiring, more and more, researches that highlight their characteristics. In this context, the study of manufacturing techniques becomes increasingly necessary in order to use the appropriate tools and obtain the best conditions of the materials. Thus, this article demonstrates the behavior of the materials, which used the polyester resin with ground paper residue to generate the two composites studied in this paper, Polyester/smaller paper (PO/ PME) and Polyester/large paper (PO/PMA). These two materials were molded by hot compression and subjected to manufacturing processes. Joinery equipment were chosen for the experimentation of cutting, drilling, screw insertion and sanding to analyze the performance of these composite materials. As a general result, it can be observed that the composites maintained their physical integrity, because the particles of the load remained well anchored in the matrix in the two composite materials tested, giving the finish an aspect without damages, cracks or imperfections after the operations. Therefore, it is concluded that the materials created can be submitted to the manufacturing techniques evaluated in this article, reinforcing previous studies that suggest its use in the development of products such as furniture, table tops, decorative objects and others. Thus, this study contributes to Designer has knowledge of the potential of the material and make the best use of it.
DOI: 10.6084/m9.figshare.14321787
title: Table S1:Hardground, gap and thin black shale: spatial heterogeneity of arrested carbonate sedimentation during the Jenkyns Event (T-OAE) in a Tethyan pelagic basin (Gerecse Mts, Hungary)

description: Table providing full details of the geochemical and mineralogical data