cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.5907637.v1
title: Thermodynamics of Combustion and Ideal Plasmas

description: Abstract In this work we present the thermochemistry of combustion and ideal plasmas, illustrating it with some examples related to pollutants production in engines and plasma physics. We first define the problem and then present two different but equivalent strategies to solve it: (i) determination of a complete set of chemical reactions, its equilibrium constants and balance equations; (ii) minimization of the Gibbs free energy of the system. Some examples are solved using the code CEA - Chemical Equilibrium with Application developed by NASA, which is available on the web. In one of them the adiabatic temperature and the final chemical composition of decane (C10H22 combustion is determined. In another one we explored the problem of an ideal plasma composed of He and H2O. We also present the general problem of the time development of the chemical composition in a reactive medium. This is illustrated solving the Zeldovich-Keck mechanism for the formation of NO and applying it to the problem of pollution produced by internal combustion engines. These examples may inspire teaching activities in graduation and post graduation courses in Physics and Engineering.
DOI: 10.6084/m9.figshare.5907634
title: Hirshfeld Surfaces and Nonlinear Optics on Two Conformers of a Heterocyclic Chalcone

description: Heterocyclic chalcones have been prominent in the scientific community due to various biological activities reported for these compounds. The structural knowledge of heterocyclic chalcones can help in the understanding of their mechanism of action. The Hirshfeld surfaces were used to study the supramolecular arrangement of two conformers present into asymmetric unit of the heterocyclic chalcone (2E)-3-(4-methylphenyl)-1-(pyridin-3-yl)-prop-2-en-1-one on crystalline state. In addition, the linear polarizability (α), the first hyperpolarizability (β||z), and the second hyperpolarizability (γ) of the conformers were calculated to get a better insight on the linear and nonlinear optical behaviors of these structures in presence of solvent medium, as well as their band-gap energies. The Hirshfeld surfaces confirmed the presence of C−H···N, C−H···O and C−H···C interactions in packaging stabilization. Finally, the 2D fingeprint plot was used to the quantification of contacts and indicated that there are both π···π and C−H···π interactions present in the compound.
DOI: 10.6084/m9.figshare.5907634.v1
title: Hirshfeld Surfaces and Nonlinear Optics on Two Conformers of a Heterocyclic Chalcone

description: Heterocyclic chalcones have been prominent in the scientific community due to various biological activities reported for these compounds. The structural knowledge of heterocyclic chalcones can help in the understanding of their mechanism of action. The Hirshfeld surfaces were used to study the supramolecular arrangement of two conformers present into asymmetric unit of the heterocyclic chalcone (2E)-3-(4-methylphenyl)-1-(pyridin-3-yl)-prop-2-en-1-one on crystalline state. In addition, the linear polarizability (α), the first hyperpolarizability (β||z), and the second hyperpolarizability (γ) of the conformers were calculated to get a better insight on the linear and nonlinear optical behaviors of these structures in presence of solvent medium, as well as their band-gap energies. The Hirshfeld surfaces confirmed the presence of C−H···N, C−H···O and C−H···C interactions in packaging stabilization. Finally, the 2D fingeprint plot was used to the quantification of contacts and indicated that there are both π···π and C−H···π interactions present in the compound.
DOI: 10.6084/m9.figshare.5907628
title: Experimental Multi-scale analysis of Carbon/Epoxy Composites Nano-Reinforced by Carbon Nanotubes/Multi-layer Graphene

description: Nano-size structures, nanotubes/multi-layer graphene (CNT/MLG), were dispersed into epoxy system by a combination of sonication and high shear mixing. To avoid CNT/MLG agglomeration, a non-covalent functionalization were performed using surfactants, CO890 - Polyoxyethylene (40) nonylphenyl ether and SDBS - sodium dodecyl benzene sulfonate. Raman spectroscopy and Fourier transformed Infra-red analysis indicated that CO890-MLG and SDBS-CNT have strong chemical interactions. Atomic force microscopy revealed formation of "spike-like" nanostructures for SDBS-CNT combination and "wall-like" nano-shape structures for the CO890-MLG ones. Tensile tests data indicate no significant change on stiffness. In average, the ultimate stress increased around 18%, while toughness had an improvement close to 62%. SDBS-CNT and CO890-MLG at small concentrations (0.075 wt. %) are probably the best options for nano-reinforcement of carbon/epoxy composites.
DOI: 10.6084/m9.figshare.5907628.v1
title: Experimental Multi-scale analysis of Carbon/Epoxy Composites Nano-Reinforced by Carbon Nanotubes/Multi-layer Graphene

description: Nano-size structures, nanotubes/multi-layer graphene (CNT/MLG), were dispersed into epoxy system by a combination of sonication and high shear mixing. To avoid CNT/MLG agglomeration, a non-covalent functionalization were performed using surfactants, CO890 - Polyoxyethylene (40) nonylphenyl ether and SDBS - sodium dodecyl benzene sulfonate. Raman spectroscopy and Fourier transformed Infra-red analysis indicated that CO890-MLG and SDBS-CNT have strong chemical interactions. Atomic force microscopy revealed formation of "spike-like" nanostructures for SDBS-CNT combination and "wall-like" nano-shape structures for the CO890-MLG ones. Tensile tests data indicate no significant change on stiffness. In average, the ultimate stress increased around 18%, while toughness had an improvement close to 62%. SDBS-CNT and CO890-MLG at small concentrations (0.075 wt. %) are probably the best options for nano-reinforcement of carbon/epoxy composites.
DOI: 10.6084/m9.figshare.5907625
title: Nutrient Uptake by High-Yielding Cotton Crop in Brazil

description: ABSTRACT: Determining nutrient uptake and accumulation rates by cotton crops is important to define management strategies, especially for transgenic varieties, which are cultivated using high-technology approaches that require substantial investment to maximize yield. Currently in Brazil, the states of Bahia and Mato Grosso are responsible for 84.4 % of the total cotton growing area. In the present study, two trials were conducted in 2013, one that involved planting FM 940 GLT, FM 980 GLT, and FM 913 GLT varieties in the state of Bahia and the other which involved FM 940 GLT and FM 980 GLT varieties in the state of Mato Grosso. The aim of the two trials was to represent the two regions that currently encompass the largest areas of cotton cultivation. Tissue samples, consisting of leaves, stems, and reproductive components, were collected eleven times during the crop cycle for determination of nutrient content and shoot dry matter. After weighing, plant tissue samples were dried and ground to determine nutrient contents. Because there were no overall differences in nutrient contents and biomass accumulation of the varieties during the crop cycle, we undertook joint analysis of the data from all varieties at each site. Favorable climatic conditions in Bahia promoted plant biomass production that was twice as much as plants grown in Mato Grosso, with cotton yields of 6.2 and 3.8 t ha−1 of lint and seed, respectively. The maximum nutrient accumulation occurred between 137-150 days after emergence (DAE) for N; 143-148 for P; 172-185 for K; 100 for Ca; 144-149 for Mg; and 153-158 for S. Maximum uptake ranged from 218-362 kg ha−1 N; 26-53 kg ha−1 P; 233-506 kg ha−1 K; 91-202 kg ha−1 Ca; 28-44 kg ha−1 Mg; and 19-61 kg ha−1 S. On average, the sites revealed nutrient export of 14, 2, 23, 3, 2, and 2 kg t−1 of lint and seed for N, P, K, Ca, Mg, and S, respectively, with little variation among sites. Extraction of nutrients per area by cotton vary among sites, but nutritional requirement of cotton per unit of lint and seeds is similar independently of yield potential.
DOI: 10.6084/m9.figshare.5907622
title: Urbanization is Associated with Increased Trends in Cardiovascular Mortality Among Indigenous Populations: the PAI Study

description: Abstract Background: The cardiovascular risk burden among diverse indigenous populations is not totally known and may be influenced by lifestyle changes related to the urbanization process. Objectives: To investigate the cardiovascular (CV) mortality profile of indigenous populations during a rapid urbanization process largely influenced by governmental infrastructure interventions in Northeast Brazil. Methods: We assessed the mortality of indigenous populations (≥ 30 y/o) from 2007 to 2011 in Northeast Brazil (Bahia and Pernambuco states). Cardiovascular mortality was considered if the cause of death was in the ICD-10 CV disease group or if registered as sudden death. The indigenous populations were then divided into two groups according to the degree of urbanization based on anthropological criteria:9,10 Group 1 - less urbanized tribes (Funi-ô, Pankararu, Kiriri, and Pankararé); and Group 2 - more urbanized tribes (Tuxá, Truká, and Tumbalalá). Mortality rates of highly urbanized cities (Petrolina and Juazeiro) in the proximity of indigenous areas were also evaluated. The analysis explored trends in the percentage of CV mortality for each studied population. Statistical significance was established for p value &lt; 0.05. Results: There were 1,333 indigenous deaths in tribes of Bahia and Pernambuco (2007-2011): 281 in Group 1 (1.8% of the 2012 group population) and 73 in Group 2 (3.7% of the 2012 group population), CV mortality of 24% and 37%, respectively (p = 0.02). In 2007-2009, there were 133 deaths in Group 1 and 44 in Group 2, CV mortality of 23% and 34%, respectively. In 2009-2010, there were 148 deaths in Group 1 and 29 in Group 2, CV mortality of 25% and 41%, respectively. Conclusions: Urbanization appears to influence increases in CV mortality of indigenous peoples living in traditional tribes. Lifestyle and environmental changes due to urbanization added to suboptimal health care may increase CV risk in this population.
DOI: 10.6084/m9.figshare.5907625.v1
title: Nutrient Uptake by High-Yielding Cotton Crop in Brazil

description: ABSTRACT: Determining nutrient uptake and accumulation rates by cotton crops is important to define management strategies, especially for transgenic varieties, which are cultivated using high-technology approaches that require substantial investment to maximize yield. Currently in Brazil, the states of Bahia and Mato Grosso are responsible for 84.4 % of the total cotton growing area. In the present study, two trials were conducted in 2013, one that involved planting FM 940 GLT, FM 980 GLT, and FM 913 GLT varieties in the state of Bahia and the other which involved FM 940 GLT and FM 980 GLT varieties in the state of Mato Grosso. The aim of the two trials was to represent the two regions that currently encompass the largest areas of cotton cultivation. Tissue samples, consisting of leaves, stems, and reproductive components, were collected eleven times during the crop cycle for determination of nutrient content and shoot dry matter. After weighing, plant tissue samples were dried and ground to determine nutrient contents. Because there were no overall differences in nutrient contents and biomass accumulation of the varieties during the crop cycle, we undertook joint analysis of the data from all varieties at each site. Favorable climatic conditions in Bahia promoted plant biomass production that was twice as much as plants grown in Mato Grosso, with cotton yields of 6.2 and 3.8 t ha−1 of lint and seed, respectively. The maximum nutrient accumulation occurred between 137-150 days after emergence (DAE) for N; 143-148 for P; 172-185 for K; 100 for Ca; 144-149 for Mg; and 153-158 for S. Maximum uptake ranged from 218-362 kg ha−1 N; 26-53 kg ha−1 P; 233-506 kg ha−1 K; 91-202 kg ha−1 Ca; 28-44 kg ha−1 Mg; and 19-61 kg ha−1 S. On average, the sites revealed nutrient export of 14, 2, 23, 3, 2, and 2 kg t−1 of lint and seed for N, P, K, Ca, Mg, and S, respectively, with little variation among sites. Extraction of nutrients per area by cotton vary among sites, but nutritional requirement of cotton per unit of lint and seeds is similar independently of yield potential.
DOI: 10.6084/m9.figshare.5907622.v1
title: Urbanization is Associated with Increased Trends in Cardiovascular Mortality Among Indigenous Populations: the PAI Study

description: Abstract Background: The cardiovascular risk burden among diverse indigenous populations is not totally known and may be influenced by lifestyle changes related to the urbanization process. Objectives: To investigate the cardiovascular (CV) mortality profile of indigenous populations during a rapid urbanization process largely influenced by governmental infrastructure interventions in Northeast Brazil. Methods: We assessed the mortality of indigenous populations (≥ 30 y/o) from 2007 to 2011 in Northeast Brazil (Bahia and Pernambuco states). Cardiovascular mortality was considered if the cause of death was in the ICD-10 CV disease group or if registered as sudden death. The indigenous populations were then divided into two groups according to the degree of urbanization based on anthropological criteria:9,10 Group 1 - less urbanized tribes (Funi-ô, Pankararu, Kiriri, and Pankararé); and Group 2 - more urbanized tribes (Tuxá, Truká, and Tumbalalá). Mortality rates of highly urbanized cities (Petrolina and Juazeiro) in the proximity of indigenous areas were also evaluated. The analysis explored trends in the percentage of CV mortality for each studied population. Statistical significance was established for p value &lt; 0.05. Results: There were 1,333 indigenous deaths in tribes of Bahia and Pernambuco (2007-2011): 281 in Group 1 (1.8% of the 2012 group population) and 73 in Group 2 (3.7% of the 2012 group population), CV mortality of 24% and 37%, respectively (p = 0.02). In 2007-2009, there were 133 deaths in Group 1 and 44 in Group 2, CV mortality of 23% and 34%, respectively. In 2009-2010, there were 148 deaths in Group 1 and 29 in Group 2, CV mortality of 25% and 41%, respectively. Conclusions: Urbanization appears to influence increases in CV mortality of indigenous peoples living in traditional tribes. Lifestyle and environmental changes due to urbanization added to suboptimal health care may increase CV risk in this population.
DOI: 10.6084/m9.figshare.5907619
title: Use of Amphiphilic Composites based on Clay/Carbon Nanofibers as Fillers in UHMWPE

description: In this work, it is proposed a new strategy to improve the dispersion of inorganic fillers in polymeric matrices by producing surface carbon nanostructures. Clay/carbon nanofibers particles were prepared and used as fillers to improve the mechanical and thermal properties of ultra-high molecular weight polyethylene (UHMWPE). Thermogravimetry (TG), differential scanning calorimetry (DSC), elemental analyses, Raman, X-ray diffraction (XRD) and scanning electron microscopy (SEM) showed that chemical vapor deposition (CVD) with ethanol at different temperatures, i.e. 700, 800 and 900 °C with and without Fe catalyst, can be used to produce carbon (0.5-3.6 wt.%), mainly as nanofibers, on the clay surface. The use of these clay/carbon particles as fillers in UHMWPE at 1 and 3 wt.% produced an increase in the yield stress from 16 to ca. 20 MPa and Young modulus from 314 MPa for pure UHMWPE to values near 395-408 MPa. Moreover, the presence of the carbon/clay composites led to a strong improvement of the thermal properties of the UHMWPE increasing the decomposition Tonset (degradation start temperature) from 445 up to 472 °C. It was also observed by the crystallization enthalpies that the UHMWPE increased the crystallinity from 55 to 80-85% in the presence of the carbon composites. These results are discussed in terms of the strong interactions of the hydrophobic carbon nanostructures on the clay surface with the polymer hydrophobic chains.
DOI: 10.6084/m9.figshare.5907619.v1
title: Use of Amphiphilic Composites based on Clay/Carbon Nanofibers as Fillers in UHMWPE

description: In this work, it is proposed a new strategy to improve the dispersion of inorganic fillers in polymeric matrices by producing surface carbon nanostructures. Clay/carbon nanofibers particles were prepared and used as fillers to improve the mechanical and thermal properties of ultra-high molecular weight polyethylene (UHMWPE). Thermogravimetry (TG), differential scanning calorimetry (DSC), elemental analyses, Raman, X-ray diffraction (XRD) and scanning electron microscopy (SEM) showed that chemical vapor deposition (CVD) with ethanol at different temperatures, i.e. 700, 800 and 900 °C with and without Fe catalyst, can be used to produce carbon (0.5-3.6 wt.%), mainly as nanofibers, on the clay surface. The use of these clay/carbon particles as fillers in UHMWPE at 1 and 3 wt.% produced an increase in the yield stress from 16 to ca. 20 MPa and Young modulus from 314 MPa for pure UHMWPE to values near 395-408 MPa. Moreover, the presence of the carbon/clay composites led to a strong improvement of the thermal properties of the UHMWPE increasing the decomposition Tonset (degradation start temperature) from 445 up to 472 °C. It was also observed by the crystallization enthalpies that the UHMWPE increased the crystallinity from 55 to 80-85% in the presence of the carbon composites. These results are discussed in terms of the strong interactions of the hydrophobic carbon nanostructures on the clay surface with the polymer hydrophobic chains.
DOI: 10.6084/m9.figshare.5907616
title: PREPARATION OF α-ACETYLOXY-N-CYCLOHEXYLAMIDES VIA PASSERINI REACTION USING DIMETHYLCARBONATE AS ECO-FRIENDLY SOLVENT

description: A series of α-acetyloxy-N-cyclohexylamides was efficiently obtained via Passerini reaction of cyclohexyl isocyanide, acetic acid, and different aromatic and aliphatic aldehydes using refluxing dichloromethane or dimethylcarbonate (DMC). Reactions performed with DMC led to desired products in moderate to good yields, corroborating this solvent as a eco-friendly alternative to the chlorinated solvents commonly used in this transformation. The α-acetyloxy-N-cyclohexylamides thus obtained were tested against Escherichia coli, Bacillus cereus, Pseudomonas aeruginosa, and Staphylococcus aureus, as well as promastigote forms of L.(L.) amazonensis. The α-(Acetyloxy)-N-cyclohexyl-pentanamide showed low antibacterial activity against Gram-positive (S. aureus and B. cereus) and Gram negative (E. coli and P. aeruginosa) bacteria (MIC = 8,3-16,5 mmol L-1), while α-(acetyloxy)-N-cyclohexyl-4-bromo-benzeneacetamide showed leishmanicidal activitity (IC50 = 0,099 mmol L-1).
DOI: 10.6084/m9.figshare.5907616.v1
title: PREPARATION OF α-ACETYLOXY-N-CYCLOHEXYLAMIDES VIA PASSERINI REACTION USING DIMETHYLCARBONATE AS ECO-FRIENDLY SOLVENT

description: A series of α-acetyloxy-N-cyclohexylamides was efficiently obtained via Passerini reaction of cyclohexyl isocyanide, acetic acid, and different aromatic and aliphatic aldehydes using refluxing dichloromethane or dimethylcarbonate (DMC). Reactions performed with DMC led to desired products in moderate to good yields, corroborating this solvent as a eco-friendly alternative to the chlorinated solvents commonly used in this transformation. The α-acetyloxy-N-cyclohexylamides thus obtained were tested against Escherichia coli, Bacillus cereus, Pseudomonas aeruginosa, and Staphylococcus aureus, as well as promastigote forms of L.(L.) amazonensis. The α-(Acetyloxy)-N-cyclohexyl-pentanamide showed low antibacterial activity against Gram-positive (S. aureus and B. cereus) and Gram negative (E. coli and P. aeruginosa) bacteria (MIC = 8,3-16,5 mmol L-1), while α-(acetyloxy)-N-cyclohexyl-4-bromo-benzeneacetamide showed leishmanicidal activitity (IC50 = 0,099 mmol L-1).
DOI: 10.6084/m9.figshare.5907613
title: Application of hypergravity in Eucalyptus and Corymbia seeds

description: ABSTRACT: The aim of this study was to evaluate the growth responses of various Eucalyptus and Corymbia species subjected to different intensities of simulated hypergravity relative to the control. A centrifuge was used to simulate hypergravity. It was developed and built at the Centro de Microgravidade of the Pontifícia Universidade Católica do Rio Grande do Sul, Brazil. Seeds of five Eucalyptus and one Corymbia species (E. grandis, Eucalyptus globulus, Eucalyptus benthamii, Eucalyptus saligna, Eucalyptus dunnii, and C. maculata) were placed on moist germination paper in plastic containers and rotated at speeds simulating 5 Gz and 7 Gz for different lengths of time. Hypergravity technology significantly increased seedling production (diameter, height, and survival at 120 days) in nurseries. In E. globulus, the effects of hypergravity were significant at 7 Gz at all lengths of time (from 1 d to 9 days). Effects of hypergravity were significant in both E. benthamii and E. grandis at 7 Gz and 8 h exposure. Therefore, simulated hypergravity could be used in performance tests of Eucalyptus seedlings in early stages of development.
DOI: 10.6084/m9.figshare.5907613.v1
title: Application of hypergravity in Eucalyptus and Corymbia seeds

description: ABSTRACT: The aim of this study was to evaluate the growth responses of various Eucalyptus and Corymbia species subjected to different intensities of simulated hypergravity relative to the control. A centrifuge was used to simulate hypergravity. It was developed and built at the Centro de Microgravidade of the Pontifícia Universidade Católica do Rio Grande do Sul, Brazil. Seeds of five Eucalyptus and one Corymbia species (E. grandis, Eucalyptus globulus, Eucalyptus benthamii, Eucalyptus saligna, Eucalyptus dunnii, and C. maculata) were placed on moist germination paper in plastic containers and rotated at speeds simulating 5 Gz and 7 Gz for different lengths of time. Hypergravity technology significantly increased seedling production (diameter, height, and survival at 120 days) in nurseries. In E. globulus, the effects of hypergravity were significant at 7 Gz at all lengths of time (from 1 d to 9 days). Effects of hypergravity were significant in both E. benthamii and E. grandis at 7 Gz and 8 h exposure. Therefore, simulated hypergravity could be used in performance tests of Eucalyptus seedlings in early stages of development.