cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.10296500
title: Imidazolium-based Ionic Liquids Impregnated in Silica and Alumina Supports for CO2 Capture

description: Ionic liquids (ILs) physical immobilization in solid materials is a key strategy for developing efficient and low cost CO2 capture processes. In this work, two porous commercial substrates with different characteristics (silica and alumina) were impregnated with ILs by physical wet method. Imidazolium based IL combined with [Br]- and [Tf2N]- anions were used in impregnation process. CO2 sorption capacity and selectivity (CO2/N2) of these materials were investigated. The best results regarding CO2/N2 selectivity and CO2 sorption were obtained with [Tf2N]- anion. In relation to solid support, commercial alumina exhibited enhanced CO2 uptake and higher selective capacity (CO2/N2) (6.1 (± 0.1)). Combination of commercial alumina as support and 20 wt% of mbmim [Tf2N] resulted in higher CO2/N2 selectivity of 9.5 ± 1.0. In addition, this material also showed fast sorption kinetics when compared to pure IL besides reuse capacity.
DOI: 10.6084/m9.figshare.10296503
title: Production of Carbon Foams from Rice Husk

description: The production of a material with rigid, multifunctional three-dimensional porous structure at a low cost is still challenging to date. In this work, a light and rigid carbon foam was prepared using rice husk as the basic element through a simple fermentation process followed by carbonization. For the fermentation process, the amount of biological yeast (7.5 g for the carbon foam CA-1P and 5 g for the carbon foam CA-2P) was used to evaluate its influence on the morphology of the foams. In order to prove that the heat treatment made in the foam alters the hydrophilic character of the rice husk foam, a chemical treatment with steam deposition was carried out. The foams were characterized by the following analyzes: apparent density, micrograph, thermogravimetry, contact angle, water sorption capacity and thermal conductivity. Visually, the CA-1P foams presented a structure with larger pores due to the greater amount of yeast used in its formulation. The heat treatment of rice potato foams proved to be as efficient as the chemical treatment for water contact angle above 90º, proving the ability of the foams to repel water/moisture. The thermal conductivity of the foams (0.029 and 0.026 W m-1 K-1 for CA-1P and CA-2P, respectively) was close to the conductivity of polyurethane foams (0.032 W m-1 K-1). Thus, the method used in the production of the carbon foams produced from the rice husk proved to be effective. In addition, the foams produced have the potential to be used for thermal insulation.
DOI: 10.6084/m9.figshare.10296509.v1
title: Study of the Moisture Absorption in Polymer Composites Reinforced with Vegetal Fiber Using Langmuir’s Model

description: This work aims to numerically study the moisture absorption in polymer composites reinforced with vegetal fiber, using the diffusive model of Langmuir, which considers the existence of water molecules inside the material free to diffuse and adsorb at the capillaries walls, in the solid. A three-dimensional and transient mathematical modelling to describe the water absorption process by the composite and its numerical solution via finite volume method are presented and discussed. Results of the free solute concentration, entrapped solute concentration, local moisture content and average moisture content obtained at different instants of the process are presented and analyzed. It was verified that the concentration gradients of the molecules (free and entrapped) are higher at the material surface. In addition, as the concentration of free water increases, there is also an increase in entrapped water concentration within the material at any time of the process.
DOI: 10.6084/m9.figshare.10296500.v1
title: Imidazolium-based Ionic Liquids Impregnated in Silica and Alumina Supports for CO2 Capture

description: Ionic liquids (ILs) physical immobilization in solid materials is a key strategy for developing efficient and low cost CO2 capture processes. In this work, two porous commercial substrates with different characteristics (silica and alumina) were impregnated with ILs by physical wet method. Imidazolium based IL combined with [Br]- and [Tf2N]- anions were used in impregnation process. CO2 sorption capacity and selectivity (CO2/N2) of these materials were investigated. The best results regarding CO2/N2 selectivity and CO2 sorption were obtained with [Tf2N]- anion. In relation to solid support, commercial alumina exhibited enhanced CO2 uptake and higher selective capacity (CO2/N2) (6.1 (± 0.1)). Combination of commercial alumina as support and 20 wt% of mbmim [Tf2N] resulted in higher CO2/N2 selectivity of 9.5 ± 1.0. In addition, this material also showed fast sorption kinetics when compared to pure IL besides reuse capacity.
DOI: 10.6084/m9.figshare.10296503.v1
title: Production of Carbon Foams from Rice Husk

description: The production of a material with rigid, multifunctional three-dimensional porous structure at a low cost is still challenging to date. In this work, a light and rigid carbon foam was prepared using rice husk as the basic element through a simple fermentation process followed by carbonization. For the fermentation process, the amount of biological yeast (7.5 g for the carbon foam CA-1P and 5 g for the carbon foam CA-2P) was used to evaluate its influence on the morphology of the foams. In order to prove that the heat treatment made in the foam alters the hydrophilic character of the rice husk foam, a chemical treatment with steam deposition was carried out. The foams were characterized by the following analyzes: apparent density, micrograph, thermogravimetry, contact angle, water sorption capacity and thermal conductivity. Visually, the CA-1P foams presented a structure with larger pores due to the greater amount of yeast used in its formulation. The heat treatment of rice potato foams proved to be as efficient as the chemical treatment for water contact angle above 90º, proving the ability of the foams to repel water/moisture. The thermal conductivity of the foams (0.029 and 0.026 W m-1 K-1 for CA-1P and CA-2P, respectively) was close to the conductivity of polyurethane foams (0.032 W m-1 K-1). Thus, the method used in the production of the carbon foams produced from the rice husk proved to be effective. In addition, the foams produced have the potential to be used for thermal insulation.
DOI: 10.6084/m9.figshare.10296494
title: Preparation of Syntactic Foams made from Green Polyethylene and Glass Microspheres: Morphological and Mechanical Characterization

description: Polymeric syntactic foams are composites made from the mixture of Hollow Glass Microspheres (HGM) and polymer matrices. One of their main characteristics is their low density and the production of these composites using a matrix derived from renewable sources potentiates their development without neglecting sustainability. In this paper , the properties of High Density Polyethylene (HDPE)/HGM syntactic foams containing 1% and 5% w/w HGM and 5% w/w of a compatibilizer are assessed. The composites were prepared by two processing routes: single screw extruder and twin screw extruder. The morphology and mechanical properties (tensile and impact) of the syntactic foams thus manufactured were ascertained. Morphological analysis indicated that matrix/filler adhesion was poor for all samples and that the best HGM dispersions were obtained in twin screw extruded samples. Mechanical properties were affected by the processing route adopted and by the content of hollow glass microspheres added. Elastic modulus, tensile strength and strain were reduced by 20, 10 and 23%, respectively, in systems processed in a twin screw extruder. Impact strength was the exception, with an increase of more than 300%. Higher contents of hollow glass microspheres led to reductions in mechanical strength of the syntactic foams, varying from 5% for the elastic modulus to 50% for strain.
DOI: 10.6084/m9.figshare.10296482
title: Characteristics of adhesive bonding with enamel deproteinization

description: ABSTRACT Objective: To evaluate the effect of using sodium hypochlorite (NaOCl) on the bond characteristics of orthodontic metal brackets bonded to enamel surface using three adhesive systems. Methods: One hundred twenty premolars were selected and randomly divided into two equal groups of 60 teeth/ each (Groups I and II). The teeth of Group I were left untreated while those of Group II were exposed to 5.25% NaOCl for 1 minute. The teeth in either group were randomly subdivided into three equal subgroups of 20 teeth/ each (A, B and C), according to the type of adhesive system used to bond the brackets. In Subgroup A, phosphoric acid + Transbond XT primer and adhesive were used. In subgroup B, Transbond Plus self-etching primer (SEP) + Transbond XT adhesive were utilized. In subgroup C, phosphoric acid + SmartBond LC adhesive were used. The shear bond strength (SBS) and the degree of adhesive penetration to enamel surface were assessed. Data analyses were performed using ANOVA, post-hoc (LSD), t and chi-square test. Results: Transbond XT had significantly higher SBS than SmartBond LC (p&lt; 0.05). Phosphoric acid provided significantly higher SBS and degree of adhesive penetration than SEP (p&lt; 0.05). NaOCl significantly increased SBS and degree of adhesive penetration in Subgroups B and C (p&lt; 0.05). Conclusion: Adhesion quality of Transbond XT adhesive is better than SmartBond LC. Phosphoric acid is more effective than SEP. NaOCl enhances the bond characteristics.
DOI: 10.6084/m9.figshare.10296488
title: Corrosion Resistance of Cu-Alloyed Precipitation Hardenable Duplex Stainless Steel ASTM A890 Grade 1B

description: Duplex stainless steels (DSS) are corrosion resistant alloys largely used in chemical and petrochemical industries. Some commercial DSS contain 0.5-1.0% copper addition to improve the corrosion resistance by reducing the corrosion rate in non-oxidizing environments. Higher copper addition (≥ 2%) can also hard by precipitation, especially when fine copper precipitates (ε phase) are produced. In this work, a cast copper alloyed DSS type ASTM A890 grade 1B with 3.01%Cu was investigated. Different levels of hardness were produced by solution treatment and aging at 450, 500, 550 and 600 oC for periods of time up to 1 hour. The corrosion resistance of aged DSS was evaluated by electrochemical tests in three media: 0.6 mol/L NaCl, 0.3 mol/L H2SO4 and 0.6 mol/L NaCl + 0.3 mol/L H2SO4 solutions. The results indicate that the effect of Cu addition depends on the media studied. Polarization studies in 0.6 mol/L NaCl showed a small anodic current peak occurred at around 400 mV vs. Ag/AgCl, with a strong influence on the passive film stability. Additionally, chronoamperometric measurements at 400 mV vs. Ag/AgCl showed a high electrochemical activity for the samples in 0.6 mol/L NaCl.
DOI: 10.6084/m9.figshare.10296491
title: Morphological and Structural Variations in Anodic Films grown on Polished and Electropolished Titanium Substrates

description: The objective of this work was to investigate the effects of anodization parameters on the anatase phase formation of titanium oxide films, which have been grown on both electropolished and non-electropolished titanium surfaces by direct current anodization in 0.25 and 2.5 mol L-1 H3PO4 solutions, respectively, at three anodization times (3, 6 and 12 hours). SEM, Raman spectroscopy and X-ray diffraction techniques revealed the characteristics of anodic films. Films were characterized according to presence of crystalline nuclei of anatase phase on an amorphous matrix. It was found that differences in size, shape and distribution of crystalline grains on anodized surfaces are affected by the type of polishing given to substrates. The particles on electropolished surfaces were grown in well-defined layers following cone-shaped grains. On the other hand, the crystallization phenomenon on non-electropolished substrates has led to the appearance of smaller particle sizes and a larger number of particles distributed along the surface as well.
DOI: 10.6084/m9.figshare.10296494.v1
title: Preparation of Syntactic Foams made from Green Polyethylene and Glass Microspheres: Morphological and Mechanical Characterization

description: Polymeric syntactic foams are composites made from the mixture of Hollow Glass Microspheres (HGM) and polymer matrices. One of their main characteristics is their low density and the production of these composites using a matrix derived from renewable sources potentiates their development without neglecting sustainability. In this paper , the properties of High Density Polyethylene (HDPE)/HGM syntactic foams containing 1% and 5% w/w HGM and 5% w/w of a compatibilizer are assessed. The composites were prepared by two processing routes: single screw extruder and twin screw extruder. The morphology and mechanical properties (tensile and impact) of the syntactic foams thus manufactured were ascertained. Morphological analysis indicated that matrix/filler adhesion was poor for all samples and that the best HGM dispersions were obtained in twin screw extruded samples. Mechanical properties were affected by the processing route adopted and by the content of hollow glass microspheres added. Elastic modulus, tensile strength and strain were reduced by 20, 10 and 23%, respectively, in systems processed in a twin screw extruder. Impact strength was the exception, with an increase of more than 300%. Higher contents of hollow glass microspheres led to reductions in mechanical strength of the syntactic foams, varying from 5% for the elastic modulus to 50% for strain.
DOI: 10.6084/m9.figshare.10296482.v1
title: Characteristics of adhesive bonding with enamel deproteinization

description: ABSTRACT Objective: To evaluate the effect of using sodium hypochlorite (NaOCl) on the bond characteristics of orthodontic metal brackets bonded to enamel surface using three adhesive systems. Methods: One hundred twenty premolars were selected and randomly divided into two equal groups of 60 teeth/ each (Groups I and II). The teeth of Group I were left untreated while those of Group II were exposed to 5.25% NaOCl for 1 minute. The teeth in either group were randomly subdivided into three equal subgroups of 20 teeth/ each (A, B and C), according to the type of adhesive system used to bond the brackets. In Subgroup A, phosphoric acid + Transbond XT primer and adhesive were used. In subgroup B, Transbond Plus self-etching primer (SEP) + Transbond XT adhesive were utilized. In subgroup C, phosphoric acid + SmartBond LC adhesive were used. The shear bond strength (SBS) and the degree of adhesive penetration to enamel surface were assessed. Data analyses were performed using ANOVA, post-hoc (LSD), t and chi-square test. Results: Transbond XT had significantly higher SBS than SmartBond LC (p&lt; 0.05). Phosphoric acid provided significantly higher SBS and degree of adhesive penetration than SEP (p&lt; 0.05). NaOCl significantly increased SBS and degree of adhesive penetration in Subgroups B and C (p&lt; 0.05). Conclusion: Adhesion quality of Transbond XT adhesive is better than SmartBond LC. Phosphoric acid is more effective than SEP. NaOCl enhances the bond characteristics.
DOI: 10.6084/m9.figshare.10296488.v1
title: Corrosion Resistance of Cu-Alloyed Precipitation Hardenable Duplex Stainless Steel ASTM A890 Grade 1B

description: Duplex stainless steels (DSS) are corrosion resistant alloys largely used in chemical and petrochemical industries. Some commercial DSS contain 0.5-1.0% copper addition to improve the corrosion resistance by reducing the corrosion rate in non-oxidizing environments. Higher copper addition (≥ 2%) can also hard by precipitation, especially when fine copper precipitates (ε phase) are produced. In this work, a cast copper alloyed DSS type ASTM A890 grade 1B with 3.01%Cu was investigated. Different levels of hardness were produced by solution treatment and aging at 450, 500, 550 and 600 oC for periods of time up to 1 hour. The corrosion resistance of aged DSS was evaluated by electrochemical tests in three media: 0.6 mol/L NaCl, 0.3 mol/L H2SO4 and 0.6 mol/L NaCl + 0.3 mol/L H2SO4 solutions. The results indicate that the effect of Cu addition depends on the media studied. Polarization studies in 0.6 mol/L NaCl showed a small anodic current peak occurred at around 400 mV vs. Ag/AgCl, with a strong influence on the passive film stability. Additionally, chronoamperometric measurements at 400 mV vs. Ag/AgCl showed a high electrochemical activity for the samples in 0.6 mol/L NaCl.
DOI: 10.6084/m9.figshare.10296491.v1
title: Morphological and Structural Variations in Anodic Films grown on Polished and Electropolished Titanium Substrates

description: The objective of this work was to investigate the effects of anodization parameters on the anatase phase formation of titanium oxide films, which have been grown on both electropolished and non-electropolished titanium surfaces by direct current anodization in 0.25 and 2.5 mol L-1 H3PO4 solutions, respectively, at three anodization times (3, 6 and 12 hours). SEM, Raman spectroscopy and X-ray diffraction techniques revealed the characteristics of anodic films. Films were characterized according to presence of crystalline nuclei of anatase phase on an amorphous matrix. It was found that differences in size, shape and distribution of crystalline grains on anodized surfaces are affected by the type of polishing given to substrates. The particles on electropolished surfaces were grown in well-defined layers following cone-shaped grains. On the other hand, the crystallization phenomenon on non-electropolished substrates has led to the appearance of smaller particle sizes and a larger number of particles distributed along the surface as well.
DOI: 10.6084/m9.figshare.10296464
title: Inhibitory effects of tanshinone IIA from Salvia miltiorrhiza Bge on human bladder cancer BIU-87 cells and xenograft in nude mice

description: Abstract The objective of this study was to investigate the inhibitory effects of tanshinone IIA on human bladder cancer BIU-87 cells and the xenograft in nude mice. BIU-87 cells were treated with tanshinone IIA with concentration of 0.5, 1, 2 and 4 g/L. The cell proliferation, cycle and apoptosis were detected. The nude mice with BIU-87 cell xenograft were treated with normal saline (control), 5-fluorouracil (5-FU), 200, 400 and 600 mg/kg tanshinone IIA, respectively. The animal body weight and growth of tumor were measured. The expressions of B-cell lymphoma-2 (Bcl-2), Caspase-3 and proliferating cell nuclear antigen (PCNA) protein in xenograft were detected. The apoptosis index of cells was determined. Results showed that, tanshinone IIA inhibited the proliferation of BIU-87 cells, promoted their apoptosis, and arrested more cells in G0/G1 phase. Tanshinone IIA significantly inhibited the growth of xenograft in nude mice and promoted the apoptosis of tumor cells in xenograft. Tanshinone IIA down-regulated Bcl-2 and PCNA expression and up-regulated Caspase-3 expression in xenograft. In conclusion, tanshinone IIA has inhibitory effects on human bladder cancer BIU-87 cells, and can inhibit the BIU-87 cells xenograft in nude mice.
DOI: 10.6084/m9.figshare.10296458
title: Experimental evaluation on the structural behavior of truss shear connectors in composite steel-concrete beams

description: Abstract The composite structures have great advantages in terms of structural and constructive aspects, with the shear connectors being decisive for obtaining the interaction between the structural elements and for the distribution of the stresses in the structure, taking advantage of the potentiality of each constituent material of the composite structure (steel and concrete). This work, through experimental studies, presents the development of a shear connector (Truss connector) proposed for use in a concrete-steel composite beam. The proposed connector is easy to implement and can serve as a viable alternative to the use of stud or U connectors. It was idealized a connector geometry that would provide low production cost, ease of execution, higher values of resistant load, efficiency as regards the relative sliding resistance between the metal profile and the concrete slab, as well as the efficiency regarding the resistance to the spacing of the slabs in relation to the metal profile (uplift). In order to evaluate the behavior of Truss connectors, 6 experimental models were constructed for push-out tests, 3 with 12.5 mm diameter Truss connectors and 3 with 19.0 mm diameter stud bolt connectors. The behavior of the models was investigated with respect to the loads of rupture, the transversal displacements between the concrete slabs and the relative vertical slide between the reinforced concrete slabs and the metallic profiles of the models. The results of the experimental analyzes provided an overview of the operation of the Truss and stud bolt connectors, with significant results that showed advantages of the Truss connector in relation to the stud connector considering the parameters analyzed in this work.
DOI: 10.6084/m9.figshare.10296458.v1
title: Experimental evaluation on the structural behavior of truss shear connectors in composite steel-concrete beams

description: Abstract The composite structures have great advantages in terms of structural and constructive aspects, with the shear connectors being decisive for obtaining the interaction between the structural elements and for the distribution of the stresses in the structure, taking advantage of the potentiality of each constituent material of the composite structure (steel and concrete). This work, through experimental studies, presents the development of a shear connector (Truss connector) proposed for use in a concrete-steel composite beam. The proposed connector is easy to implement and can serve as a viable alternative to the use of stud or U connectors. It was idealized a connector geometry that would provide low production cost, ease of execution, higher values of resistant load, efficiency as regards the relative sliding resistance between the metal profile and the concrete slab, as well as the efficiency regarding the resistance to the spacing of the slabs in relation to the metal profile (uplift). In order to evaluate the behavior of Truss connectors, 6 experimental models were constructed for push-out tests, 3 with 12.5 mm diameter Truss connectors and 3 with 19.0 mm diameter stud bolt connectors. The behavior of the models was investigated with respect to the loads of rupture, the transversal displacements between the concrete slabs and the relative vertical slide between the reinforced concrete slabs and the metallic profiles of the models. The results of the experimental analyzes provided an overview of the operation of the Truss and stud bolt connectors, with significant results that showed advantages of the Truss connector in relation to the stud connector considering the parameters analyzed in this work.