cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.14321850
title: Evaluation of adsortive potential of coconut mesocarp in the removal of reactive red dye 195 in aqueous effluents

description: ABSTRACT The textile industry produces dye-rich effluents that when released in hydric bodies hamper the penetration of sunlight, impairing photosynthetic processes. Besides that, dyes have been indicated as potentially toxic substances. In general, the processes of removing of these contaminants have been much studied, with the technique of adsorption standing out for its high efficiency, in addition to operational advantages and the possibility of reuse agricultural waste as adsorbents, benefiting the environment and reducing costs. The present work had as objective to study the performance of coconut mesocarp utilized as adsorbent in the bleaching process of synthetic effluent containing 25 g.L-1 of reactive red 195 dye. The adsorbent were characterized by granulometry, thermogravimetric analysis and zero point charge. Kinetic and balance study was realized, applying kinetic models and adsorption isotherms. The adsorbent exhibited removal efficiency of 89.92 % in 120 min. The maximum adsorption capacity was 24.04 g.g-1 at 30 °C. The kinetic study showed that the data was better adjusted by an Elovich equation, indicating slow chemisorption. The thermodynamic study exhibited that the adsorption process is exothermic and spontaneous for all the temperatures evaluated.
DOI: 10.6084/m9.figshare.14321850.v1
title: Evaluation of adsortive potential of coconut mesocarp in the removal of reactive red dye 195 in aqueous effluents

description: ABSTRACT The textile industry produces dye-rich effluents that when released in hydric bodies hamper the penetration of sunlight, impairing photosynthetic processes. Besides that, dyes have been indicated as potentially toxic substances. In general, the processes of removing of these contaminants have been much studied, with the technique of adsorption standing out for its high efficiency, in addition to operational advantages and the possibility of reuse agricultural waste as adsorbents, benefiting the environment and reducing costs. The present work had as objective to study the performance of coconut mesocarp utilized as adsorbent in the bleaching process of synthetic effluent containing 25 g.L-1 of reactive red 195 dye. The adsorbent were characterized by granulometry, thermogravimetric analysis and zero point charge. Kinetic and balance study was realized, applying kinetic models and adsorption isotherms. The adsorbent exhibited removal efficiency of 89.92 % in 120 min. The maximum adsorption capacity was 24.04 g.g-1 at 30 °C. The kinetic study showed that the data was better adjusted by an Elovich equation, indicating slow chemisorption. The thermodynamic study exhibited that the adsorption process is exothermic and spontaneous for all the temperatures evaluated.
DOI: 10.6084/m9.figshare.14321851
title: Influence of preheating on elastic modulus, flexural and cohesive strength of bulk-fill composites

description: ABSTRACT The purpose of this study was to evaluate the influence of pre-heating of bulk-fill composites on flexural strength, modulus of elasticity and cohesive strength. Five composites were tested: Tetric N-Ceram Bulk-fill (TBF). X-tra Fill (XTF), Filtek Bulk-fill (FBF), Aura Bulk-fill (ABF) and Filtek Z250 (FZ, control). The samples were conditioned at 37ºC for 24 hours before being tested. Results were statistically analyzed by ANOVA and Tukey test. FBF, XTF and FZ composites had the highest cohesive strengths, and preheating positively influenced this property. XTF and FBF materials without preheating showed the highest values of flexural strength and modulus of elasticity. For these properties, preheating caused a reduction in XBF, FBF and ABF resins, had no effect on TBF resin and caused an increase in FZ resin. The preheating positively influenced the cohesive strength of the studied materials, improving the performance of all bulk-fill resins. Tetric N-Ceram Bulk Fill/ Ivoclar did not show changes on modulus of elasticity and flexural strength when preheated, while the other bulk-fill composites presented lower results for these two properties after heating.
DOI: 10.6084/m9.figshare.14321854.v1
title: Effect of iron mining tailings as a red ceramic additive for decreased sintering temperature

description: ABSTRACT The ceramic materials industry includes the burning process at high temperatures in a way that the energy expense of the conventional methods of burning is very high. Using alternative raw materials shows a large potential in this process, such as wastes from other industrial processes, which may reduce the burning temperature of the ceramics, providing desirable characteristics with lower energy expense, as additives that have a high fluxes content, such as iron ore tailings. The waste used had its chemical composition analyzed by X-Ray Fluorescence, mineralogical composition analyzed by X-ray Diffraction and Granulometry by sieving and sedimentation. To study the properties of ceramic test pieces with addition of wastes, we used three different temperatures in the burning process to test if the use of the waste could improve its characteristics. We produced test pieces including a mixture of soil with 10 and 20% content of waste exposed to the sintering process at temperatures of 750, 850 and 950° C. To test the technological properties of the pieces we performed tests of linear shrinkage, loss on fire, coloring, water absorption, apparent porosity, compressive strength and scanning electron microscopy. The color of the test pieces was intensified, and the tested characteristics that showed improvements when the burning temperature decreased. However, at defined concentrations there was little variation in the test pieces produced with pure soil.
DOI: 10.6084/m9.figshare.14321854
title: Effect of iron mining tailings as a red ceramic additive for decreased sintering temperature

description: ABSTRACT The ceramic materials industry includes the burning process at high temperatures in a way that the energy expense of the conventional methods of burning is very high. Using alternative raw materials shows a large potential in this process, such as wastes from other industrial processes, which may reduce the burning temperature of the ceramics, providing desirable characteristics with lower energy expense, as additives that have a high fluxes content, such as iron ore tailings. The waste used had its chemical composition analyzed by X-Ray Fluorescence, mineralogical composition analyzed by X-ray Diffraction and Granulometry by sieving and sedimentation. To study the properties of ceramic test pieces with addition of wastes, we used three different temperatures in the burning process to test if the use of the waste could improve its characteristics. We produced test pieces including a mixture of soil with 10 and 20% content of waste exposed to the sintering process at temperatures of 750, 850 and 950° C. To test the technological properties of the pieces we performed tests of linear shrinkage, loss on fire, coloring, water absorption, apparent porosity, compressive strength and scanning electron microscopy. The color of the test pieces was intensified, and the tested characteristics that showed improvements when the burning temperature decreased. However, at defined concentrations there was little variation in the test pieces produced with pure soil.
DOI: 10.6084/m9.figshare.14321856
title: Reinforcing effects on Portland cement paste with graphene oxide obtained Green chemistry methods

description: ABSTRACT The main objective of this paper is to synthesize graphene oxide (GO) in a more sustainable way and add it to Portland cement paste. The most commonly used method of obtaining GO is the Hummers method, in which the washing of the material is done with water, resulting in large amounts of aqueous acid waste. This process leads to environmental sustainability problem, due to the possible damages to the environment. Aiming for a modern approach in the precepts of green chemistry for obtaining GO, it is proposed to replace the washing with water by neutralizing the solution with calcium carbonate to reduce these toxic residues. To verify the efficiency of green synthesis, physicochemical comparisons of GO samples obtained by both the Hummers method (GO) and the green method (GOv) were performed. The samples were analyzed by XRD, FTIR and RAMAN,and SEM. The analyses of the GOv suspension did not indicate the presence of new crystalline phases, but the formation of the gypsum phase was observed in the dry sample in the hot chamber. The results showed the efficiency in the production of GO. For the production of Portland cement paste, we added a proportion of 0,1; 0,2; 0,3; 0,4; 0,5; 0,75 and 1% of GOv and, then compressive strength tests were performed on the specimens. A maximum efficiency in the mechanical strength property was observed with addition of 0.3% of GOv in the traces. In comparative studies of electron microscopy in the 0.3% traces against 1.0% of GOv traces, the aggregation of GO lamellae in the traces with higher concentration can be observed, which results in lower resistance of the latter. This research presented a proposal with less environmental impact for the production of cement composites GO by a simple method.
DOI: 10.6084/m9.figshare.14321856.v1
title: Reinforcing effects on Portland cement paste with graphene oxide obtained Green chemistry methods

description: ABSTRACT The main objective of this paper is to synthesize graphene oxide (GO) in a more sustainable way and add it to Portland cement paste. The most commonly used method of obtaining GO is the Hummers method, in which the washing of the material is done with water, resulting in large amounts of aqueous acid waste. This process leads to environmental sustainability problem, due to the possible damages to the environment. Aiming for a modern approach in the precepts of green chemistry for obtaining GO, it is proposed to replace the washing with water by neutralizing the solution with calcium carbonate to reduce these toxic residues. To verify the efficiency of green synthesis, physicochemical comparisons of GO samples obtained by both the Hummers method (GO) and the green method (GOv) were performed. The samples were analyzed by XRD, FTIR and RAMAN,and SEM. The analyses of the GOv suspension did not indicate the presence of new crystalline phases, but the formation of the gypsum phase was observed in the dry sample in the hot chamber. The results showed the efficiency in the production of GO. For the production of Portland cement paste, we added a proportion of 0,1; 0,2; 0,3; 0,4; 0,5; 0,75 and 1% of GOv and, then compressive strength tests were performed on the specimens. A maximum efficiency in the mechanical strength property was observed with addition of 0.3% of GOv in the traces. In comparative studies of electron microscopy in the 0.3% traces against 1.0% of GOv traces, the aggregation of GO lamellae in the traces with higher concentration can be observed, which results in lower resistance of the latter. This research presented a proposal with less environmental impact for the production of cement composites GO by a simple method.
DOI: 10.6084/m9.figshare.14321860.v1
title: Analysis of mechanical and biological properties of fast setting time nanostructured biphasic calcium phosphate bone cement

description: ABSTRACT Over the past two decades, the development of new therapies for applications in degenerative bone tissue diseases has intensified, as well as less invasive forms of road accident trauma treatment. In this scenario, fast setting time calcium phosphate bone cement (CFCs) for injectable and/or moldable applications allows for use through minimally invasive surgical techniques. CFC arrays have attracted great interest for use in orthopedics and dentistry as substitutes for damaged parts of the osteochondral system, allowing their use in bone repair or filling. In this work, CFCs consisting of two different biphasic calcium phosphates (BCP) were processed, one with micrometric distribution and the other with nanometric distribution, sodium phosphate and carboxymethylcellulose, aiming at the use of this material in surgical procedures. The raw materials were physically and chemically characterized by X-ray diffraction, scanning electron microscopy coupled with X-ray dispersive energy spectroscopy. The setting time of the material was evaluated by Vicat tests and the mechanical strength of the CFC was evaluated through the flexural tests (tensile strength), ultramicrohardness (modulus of elasticity). Biological properties were evaluated by in vitro Tris-HCL degradation assay, cytotoxicity assay by bacterial culture and in vivo assay by the HET-CAM method. The results showed a better performance of the nanometer CFC, having a low final setting time, 22 minutes, and mechanical strength of 4 MPa, compatible with the expected expectation for cancellous bone. Biological assays confirmed the satisfactory biological response of these nanocomposites. This demonstrates that the material has potential for clinical application in place of the widely used acrylic cement.
DOI: 10.6084/m9.figshare.14321862.v1
title: A calorimetry analysis of Portland cement pastes containing superabsorbent polymer (SAP) and nanosilica (NS)

description: ABSTRACT The application of calorimetry's technique by isothermal conduction allows the evaluation of the velocity of the hydration reactions in a simple and efficient way, over time, by the heat evolution's curves. This technique can be the right tool to evaluate the superabsorbent polymer's (SAP) desorption, which is a fundamental parameter that determines the polymer's efficiency as mitigating agent of autogenous shrinkage. With the use of calorimetry, it was possible to evaluate SAP's behavior during the fresh state and the influence of nanosilica (NS) in hydration kinetics of cement compounds. Regarding the pastes analyzed in this paper, it was observed a small retard in the main peak of C-S-H formation in the pastes containing SAP and an acceleration of the hydration’s reactions of the pastes containing NS. It was also noted that the heat released is proportional to the amount of NS and SAP, what can be related to the higher hydrate’s formation.
DOI: 10.6084/m9.figshare.14321860
title: Analysis of mechanical and biological properties of fast setting time nanostructured biphasic calcium phosphate bone cement

description: ABSTRACT Over the past two decades, the development of new therapies for applications in degenerative bone tissue diseases has intensified, as well as less invasive forms of road accident trauma treatment. In this scenario, fast setting time calcium phosphate bone cement (CFCs) for injectable and/or moldable applications allows for use through minimally invasive surgical techniques. CFC arrays have attracted great interest for use in orthopedics and dentistry as substitutes for damaged parts of the osteochondral system, allowing their use in bone repair or filling. In this work, CFCs consisting of two different biphasic calcium phosphates (BCP) were processed, one with micrometric distribution and the other with nanometric distribution, sodium phosphate and carboxymethylcellulose, aiming at the use of this material in surgical procedures. The raw materials were physically and chemically characterized by X-ray diffraction, scanning electron microscopy coupled with X-ray dispersive energy spectroscopy. The setting time of the material was evaluated by Vicat tests and the mechanical strength of the CFC was evaluated through the flexural tests (tensile strength), ultramicrohardness (modulus of elasticity). Biological properties were evaluated by in vitro Tris-HCL degradation assay, cytotoxicity assay by bacterial culture and in vivo assay by the HET-CAM method. The results showed a better performance of the nanometer CFC, having a low final setting time, 22 minutes, and mechanical strength of 4 MPa, compatible with the expected expectation for cancellous bone. Biological assays confirmed the satisfactory biological response of these nanocomposites. This demonstrates that the material has potential for clinical application in place of the widely used acrylic cement.
DOI: 10.6084/m9.figshare.14321862
title: A calorimetry analysis of Portland cement pastes containing superabsorbent polymer (SAP) and nanosilica (NS)

description: ABSTRACT The application of calorimetry's technique by isothermal conduction allows the evaluation of the velocity of the hydration reactions in a simple and efficient way, over time, by the heat evolution's curves. This technique can be the right tool to evaluate the superabsorbent polymer's (SAP) desorption, which is a fundamental parameter that determines the polymer's efficiency as mitigating agent of autogenous shrinkage. With the use of calorimetry, it was possible to evaluate SAP's behavior during the fresh state and the influence of nanosilica (NS) in hydration kinetics of cement compounds. Regarding the pastes analyzed in this paper, it was observed a small retard in the main peak of C-S-H formation in the pastes containing SAP and an acceleration of the hydration’s reactions of the pastes containing NS. It was also noted that the heat released is proportional to the amount of NS and SAP, what can be related to the higher hydrate’s formation.
DOI: 10.6084/m9.figshare.14321863
title: Viability of the use of hollow trees of Astronium lecointei Ducke using wood technology and design

description: ABSTRACT With the lack of technology in the forest sector, alternatives are necessary to favor the maximization of the use of Amazonian wood, especially to those that have unfavorable characteristics for its processing. Thus, the objective of the research was to develop the design of a product with the planned design, making it and verifying the processing steps to attest the increase of the volumetric yield and the reduction of wood residues from hollow trees. With this, furniture was designed, using software to model the geometry and fitting alternatives for a six-seat dining table, with different structure and shapes. About 0.1799 m³ of Muiracatiara wood was were used to make the table, with marquetry technique on top, with Marupá wood. The final volume of the product was 0.5420 m³, and the volume yield was 30.13% considered high, for the quantity of wood used in the process. With the remainder, about 69.87% of lumber residue from table production, it was possible to make a luminaire, from discarded pieces during the wood machining. The study allowed the demonstration of the applicability of the design in the wood sector from the planning of the use of the raw material, where it was possible to verify the feasibility of the procedure using amazonic wood for the making of household items, regardless of state of quality, making the activity sustainable to the sector.
DOI: 10.6084/m9.figshare.14321863.v1
title: Viability of the use of hollow trees of Astronium lecointei Ducke using wood technology and design

description: ABSTRACT With the lack of technology in the forest sector, alternatives are necessary to favor the maximization of the use of Amazonian wood, especially to those that have unfavorable characteristics for its processing. Thus, the objective of the research was to develop the design of a product with the planned design, making it and verifying the processing steps to attest the increase of the volumetric yield and the reduction of wood residues from hollow trees. With this, furniture was designed, using software to model the geometry and fitting alternatives for a six-seat dining table, with different structure and shapes. About 0.1799 m³ of Muiracatiara wood was were used to make the table, with marquetry technique on top, with Marupá wood. The final volume of the product was 0.5420 m³, and the volume yield was 30.13% considered high, for the quantity of wood used in the process. With the remainder, about 69.87% of lumber residue from table production, it was possible to make a luminaire, from discarded pieces during the wood machining. The study allowed the demonstration of the applicability of the design in the wood sector from the planning of the use of the raw material, where it was possible to verify the feasibility of the procedure using amazonic wood for the making of household items, regardless of state of quality, making the activity sustainable to the sector.
DOI: 10.6084/m9.figshare.14321865.v1
title: Propriedades estruturais e fotofísicas da hidroxiapatita dopada com íons lantanídeos

description: ABSTRACT Hydroxyapatite (HAp) matrices doped with lanthanide ions Eu3+, Ce3+ and Gd3+, [Ca10-xLnx(PO4)6(OH)2] were obtained through the precipitation method so their photophysical properties could be studied. From the Scanning Electron Microscopy analyzes it was observed that samples doped with lanthanide ions (Ln3+) showed similarity with the morphology of pure HAp, whereas Rietveld-refined X-ray diffractograms showed that the matrix appears as the major phase (≈70%) while (≈30%) of a second phase of tricalcium phosphate (TCP) was due to the different doping levels. Adsorption isotherms obtained by the BET technique indicated that all the synthesized materials are classified as mesoporous. The emission spectra of the materials exhibit bands typical of the Ln3+ ions incorporated into the matrix structure at 573 nm (5D0→F0), 600 nm (5D0→F1), 628 nm (5D0→F2), and 698 nm (5D0 → F4) for HAp/Eu, 337-360 nm (5d → 4f) for HAp/Ce and at 425 nm for HAp/Gd.
DOI: 10.6084/m9.figshare.14321865
title: Propriedades estruturais e fotofísicas da hidroxiapatita dopada com íons lantanídeos

description: ABSTRACT Hydroxyapatite (HAp) matrices doped with lanthanide ions Eu3+, Ce3+ and Gd3+, [Ca10-xLnx(PO4)6(OH)2] were obtained through the precipitation method so their photophysical properties could be studied. From the Scanning Electron Microscopy analyzes it was observed that samples doped with lanthanide ions (Ln3+) showed similarity with the morphology of pure HAp, whereas Rietveld-refined X-ray diffractograms showed that the matrix appears as the major phase (≈70%) while (≈30%) of a second phase of tricalcium phosphate (TCP) was due to the different doping levels. Adsorption isotherms obtained by the BET technique indicated that all the synthesized materials are classified as mesoporous. The emission spectra of the materials exhibit bands typical of the Ln3+ ions incorporated into the matrix structure at 573 nm (5D0→F0), 600 nm (5D0→F1), 628 nm (5D0→F2), and 698 nm (5D0 → F4) for HAp/Eu, 337-360 nm (5d → 4f) for HAp/Ce and at 425 nm for HAp/Gd.
DOI: 10.6084/m9.figshare.14321866
title: Evaluation of the corrosion resistance of electroless Ni-P coatings on magnesium

description: ABSTRACT Magnesium and its alloys offer a wide range of applications due to their excellent properties, however, their high chemical reactivity depends on their possible application in environments that have high chloride contents, because the development of an efficient method of surface protection and Easy implementation on an industrial scale is necessary. In the present work, nickel-phosphorus (Ni-P) electrolytic coatings on magnesium substrates were obtained from a chromate-free method. Subsequently, these coatings were evaluated electrochemically by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in NaCl 3.5% wt solution. The results indicate that the coatings obtained manage to produce greater thermodynamic stability to the magnesium surfaces and reduce approximately the corrosion rate by a factor of 1000. Therefore, the methodology for obtaining the Nickel-phosphorus coatings that we propose in this work is susceptible to industrial scale.