cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.7506899.v1
title: Application viability evaluation of the Minimum Quantity Lubrication coolant technique under different flow rates in Plunge Cylindrical Grinding of the ABNT 4340 steel with aluminum oxide wheel

description: Abstract The coolant delivery technique known as Minimal Quantity Lubrication (MQL) has been employed in machining since the end of the 20th Century and has gained considerable evidence in the last years as a viable alternative to the use of the conventional coolant technique (flood). Due to the low oil flow rate delivered by the MQL technique in grinding operations, that generally varies from 20 to 240 ml / h in relation to near 600,000 ml / h flow rate of the conventional coolant technique, the MQL technique provides a reduced risk for human health and environmental damage associated with the use, maintenance and disposal of cutting fluids. In this context, this study was carried out to evaluate the application viability of the minimum quantity lubrication coolant technique under different flow rates in the plunge cylindrical grinding of ABNT 4340 steel with an aluminum oxide wheel. Three flow rates were tested: 30, 60 and 120 ml/h. Grinding trials with the conventional coolant delivery method were also tested for comparative purposes. The output variables used to assess the efficiency of the MQL technique in this work are: roughness, roundness and hardness of the workpiece. Grinding wheel wear and power consumption were also monitored. The results showed that, despite the higher values of roughness and roundness of the workpiece, as well as the grinding wheel wear, the values of these same parameters obtained after machining with the MQL technique were close to those obtained after machining with the conventional technique. No thermal damages and cracks on the machined surface, or even below the machined surface, were observed after grinding ABNT 4340 steel irrespective of the coolant-lubrication condition investigated. The results showed that the MQL with 120 ml/h can be an alternative coolant technique due to cleaner environment and lower consumption of fluid in grinding under the conditions investigated in this work.
DOI: 10.6084/m9.figshare.7511021
title: Name ambiguity influences centrality of co-authorship networks

description: Name ambiguity can create several problems in bibliometrics and Social Network Analysis studies related to this type of data. It is an unsolved issue that has become more complex in recent years due to increasing worldwide scientific publication, more specifically in far eastern countries. The aim of the article was to show how name ambiguity influences centrality metrics in Social Network Analysis. The study was based on co-authorship relations of approximately 30 000 articles indexed in Thomson Reuters/Web of Science. Three co-authorship networks were developed using different ways to record the authors' names. The results showed significant differences among the networks when considering degree centrality, closeness and betweenness. The study points out the importance of standardizing names and the need to further discuss the issue in the academic environment in an endeavor to find alternative solutions.
DOI: 10.6084/m9.figshare.7511021.v1
title: Name ambiguity influences centrality of co-authorship networks

description: Name ambiguity can create several problems in bibliometrics and Social Network Analysis studies related to this type of data. It is an unsolved issue that has become more complex in recent years due to increasing worldwide scientific publication, more specifically in far eastern countries. The aim of the article was to show how name ambiguity influences centrality metrics in Social Network Analysis. The study was based on co-authorship relations of approximately 30 000 articles indexed in Thomson Reuters/Web of Science. Three co-authorship networks were developed using different ways to record the authors' names. The results showed significant differences among the networks when considering degree centrality, closeness and betweenness. The study points out the importance of standardizing names and the need to further discuss the issue in the academic environment in an endeavor to find alternative solutions.
DOI: 10.6084/m9.figshare.6503771
title: A Statistical Dynamic Model for the Turbulent Transport of Kinetic Energy in Shear Layers

description: ABSTRACT: Dynamic statistical equations for the turbulent fluxes of scalars and momentum in incompressible flows are derived after time wise integration of the equation for the oscillating transported property, decomposing the turbulent fluxes in terms representing distinct features of the main and fluctuating flow that influence the respective turbulent transport. These expressions provide a means for discussing the gradient diffusion hypothesis for the turbulent transport, for reconsidering the mixed length model in entirely continuous terms, and for seeking possible alternatives or corrections. Applying this methodology to the turbulent transport flux of kinetic energy, two dominating terms are found: one identified with a kinetic energy gradient model for shear layers; the other related to the main velocity gradient. Accordingly, a composed, Statistical Dynamic model is proposed for the turbulent transport of kinetic energy in shear layers, adding a velocity derivative term to Daly and Harlow's generalized gradient model. This velocity derivative term is calibrated in a nearly homogeneous turbulent shear flow, and the resulting Statistical Dynamic model is proved superior to Daly and Harlow's and other gradient models in channel and boundary layer flows.
DOI: 10.6084/m9.figshare.7506281
title: Petrogenesis and tectonic of the Urucum granitic suite, Rio Doce Valley (Minas Gerais - Brazil): an example of syn to late collisional peraluminous magmatism associated with high-angle transcurrent shear zone

description: The Urucum suite (582 ± 2 Ma, zircon U-Pb age), situated in the Mid-Rio Doce Valley, eastern part of Minas Gerais State, is characterized by elongated, NW-SE and N-S trending granitic massifs associated with the Conselho Peña-Resplendor high-angle shear zone. It corresponds to a syn to late collisional magmatism that presents dominant solid-state foliation. Four facies are distinguished within the Urucum suite: (i) a porphyritic (Urucum); (ii) a medium- to coarse nequigranular (Palmital); (iii) a tourmaline-bearing; and (iv) a pegmatitic facies. These facies are peraluminous, with alumina saturation index varying from 0.98 to 1.38. SiO2 contents vary from 70.7 to 73.7 wt%, with K2O values ranging from 3.5 to 5.7 wt%, Na2O from 1.9 to 4.4 wt%, MgO from 0.6 to 1.2 wt%, and CaO from 0.3 to 0.9%. Harker-type diagrams show rather continuous trends from the less-evolved Urucum facies to the more evolved tourmaline-bearing and pegmatitic facies. The behavior of several major oxides and trace elements (Fe2O3, MgO, MnO, CaO, TiO2, Al2O3, K2O, Rb and Ba) reflects the role played by fractionation of ferromagnesian minerals, feldspars and accessory minerals. Initial Sr87/Sr86 ratios vary from 0.711 to 0.716, with εNd (580 Ma) values between -7.4 to -8.2, and Sm-Nd TDM model ages ranging from 2290 to 1840 Ma.
DOI: 10.6084/m9.figshare.7506281.v1
title: Petrogenesis and tectonic of the Urucum granitic suite, Rio Doce Valley (Minas Gerais - Brazil): an example of syn to late collisional peraluminous magmatism associated with high-angle transcurrent shear zone

description: The Urucum suite (582 ± 2 Ma, zircon U-Pb age), situated in the Mid-Rio Doce Valley, eastern part of Minas Gerais State, is characterized by elongated, NW-SE and N-S trending granitic massifs associated with the Conselho Peña-Resplendor high-angle shear zone. It corresponds to a syn to late collisional magmatism that presents dominant solid-state foliation. Four facies are distinguished within the Urucum suite: (i) a porphyritic (Urucum); (ii) a medium- to coarse nequigranular (Palmital); (iii) a tourmaline-bearing; and (iv) a pegmatitic facies. These facies are peraluminous, with alumina saturation index varying from 0.98 to 1.38. SiO2 contents vary from 70.7 to 73.7 wt%, with K2O values ranging from 3.5 to 5.7 wt%, Na2O from 1.9 to 4.4 wt%, MgO from 0.6 to 1.2 wt%, and CaO from 0.3 to 0.9%. Harker-type diagrams show rather continuous trends from the less-evolved Urucum facies to the more evolved tourmaline-bearing and pegmatitic facies. The behavior of several major oxides and trace elements (Fe2O3, MgO, MnO, CaO, TiO2, Al2O3, K2O, Rb and Ba) reflects the role played by fractionation of ferromagnesian minerals, feldspars and accessory minerals. Initial Sr87/Sr86 ratios vary from 0.711 to 0.716, with εNd (580 Ma) values between -7.4 to -8.2, and Sm-Nd TDM model ages ranging from 2290 to 1840 Ma.
DOI: 10.6084/m9.figshare.7506899
title: Application viability evaluation of the Minimum Quantity Lubrication coolant technique under different flow rates in Plunge Cylindrical Grinding of the ABNT 4340 steel with aluminum oxide wheel

description: Abstract The coolant delivery technique known as Minimal Quantity Lubrication (MQL) has been employed in machining since the end of the 20th Century and has gained considerable evidence in the last years as a viable alternative to the use of the conventional coolant technique (flood). Due to the low oil flow rate delivered by the MQL technique in grinding operations, that generally varies from 20 to 240 ml / h in relation to near 600,000 ml / h flow rate of the conventional coolant technique, the MQL technique provides a reduced risk for human health and environmental damage associated with the use, maintenance and disposal of cutting fluids. In this context, this study was carried out to evaluate the application viability of the minimum quantity lubrication coolant technique under different flow rates in the plunge cylindrical grinding of ABNT 4340 steel with an aluminum oxide wheel. Three flow rates were tested: 30, 60 and 120 ml/h. Grinding trials with the conventional coolant delivery method were also tested for comparative purposes. The output variables used to assess the efficiency of the MQL technique in this work are: roughness, roundness and hardness of the workpiece. Grinding wheel wear and power consumption were also monitored. The results showed that, despite the higher values of roughness and roundness of the workpiece, as well as the grinding wheel wear, the values of these same parameters obtained after machining with the MQL technique were close to those obtained after machining with the conventional technique. No thermal damages and cracks on the machined surface, or even below the machined surface, were observed after grinding ABNT 4340 steel irrespective of the coolant-lubrication condition investigated. The results showed that the MQL with 120 ml/h can be an alternative coolant technique due to cleaner environment and lower consumption of fluid in grinding under the conditions investigated in this work.
DOI: 10.6084/m9.figshare.6833054
title: Effect of Convergent Section Contour on the Sonic Line in Rocket Engine Nozzles

description: ABSTRACT This study made a numeric evaluation of the effect of convergent geometry on the position and profile of the sonic line in rocket engine nozzles. To validate the numerical solution, two conical nozzles, from which experimental results are available in the literature, were used as reference. The tested convergent geometries have the same values for throat radius (Rt), radius of curvature at the throat of the divergent section (Rc3), divergent length, and ratio of areas. The numerical solutions have shown that convergent geometry changes the shape of the sonic line, and nozzles with lower radius ratios (Rc2/Rt) are more sensitive to the shape of the convergent section.
DOI: 10.6084/m9.figshare.6833054.v1
title: Effect of Convergent Section Contour on the Sonic Line in Rocket Engine Nozzles

description: ABSTRACT This study made a numeric evaluation of the effect of convergent geometry on the position and profile of the sonic line in rocket engine nozzles. To validate the numerical solution, two conical nozzles, from which experimental results are available in the literature, were used as reference. The tested convergent geometries have the same values for throat radius (Rt), radius of curvature at the throat of the divergent section (Rc3), divergent length, and ratio of areas. The numerical solutions have shown that convergent geometry changes the shape of the sonic line, and nozzles with lower radius ratios (Rc2/Rt) are more sensitive to the shape of the convergent section.
DOI: 10.6084/m9.figshare.7511654
title: A Comparative Study of the Heat Input During Laser Welding of Aeronautical Aluminum Alloy AA6013-T4

description: ABSTRACT The heat input is the amount of energy supplied per unit length of the welded workpiece. In this study, the effect of two different heat inputs in laser beam welding of a high strength aluminum alloy AA6013-T4 was evaluated from macrostructural and microstructural points of view. The experiments were performed using a continuous wave 2 kW Yb-fiber laser with 100 µm spot size on the upper surface of the workpiece. Keeping the heat input at a given level, 13 or 30 J/mm, the laser power was changed from 650 W to 2 kW and the welding speed from 33 to 150 mm/s. In the condition of higher heat input 30 J/mm it was possible to obtain both cutting and welding processes. For 13 J/mm, welding processes were obtained in conduction and keyhole modes. The equiaxed grain fraction changed with changing speed for the same heat input. The laser processing induced a decrease in the hardness of the weld bead of about 25% due to the solubilization of the precipitates. The estimated absorptivities of the laser beam in the liquid aluminum changed largely with experimental conditions, from 4.6% to 10.5%, being the most significant source of error in measuring the real amount of energy absorbed in the process. For the same heat input the macrostructure of the welded surfaces, i.e., humps and dropouts, changed as well. All these facts indicate that the heat input is not a convenient method to parameterize the laser beam welding parameters aiming the same weld features.
DOI: 10.6084/m9.figshare.6503771.v1
title: A Statistical Dynamic Model for the Turbulent Transport of Kinetic Energy in Shear Layers

description: ABSTRACT: Dynamic statistical equations for the turbulent fluxes of scalars and momentum in incompressible flows are derived after time wise integration of the equation for the oscillating transported property, decomposing the turbulent fluxes in terms representing distinct features of the main and fluctuating flow that influence the respective turbulent transport. These expressions provide a means for discussing the gradient diffusion hypothesis for the turbulent transport, for reconsidering the mixed length model in entirely continuous terms, and for seeking possible alternatives or corrections. Applying this methodology to the turbulent transport flux of kinetic energy, two dominating terms are found: one identified with a kinetic energy gradient model for shear layers; the other related to the main velocity gradient. Accordingly, a composed, Statistical Dynamic model is proposed for the turbulent transport of kinetic energy in shear layers, adding a velocity derivative term to Daly and Harlow's generalized gradient model. This velocity derivative term is calibrated in a nearly homogeneous turbulent shear flow, and the resulting Statistical Dynamic model is proved superior to Daly and Harlow's and other gradient models in channel and boundary layer flows.
DOI: 10.6084/m9.figshare.7512005
title: Mini-channel Two Phase Flow of Hydrogen Peroxide: Decomposition with Silver Catalyst

description: ABSTRACT Hydrogen peroxide is a chemical compound which is commonly used as a disinfectant at lower concentrations. The chemical is called as a green propellant for space applications. Water and oxygen are the products after self-decomposition of the compound at higher concentrations. The reaction rate at lower concentrations can be enhanced by using catalysts for faster reaction rates. In the present study, an experimental analysis of the reaction rate of hydrogen peroxide (6% by volume) with silver catalyst for varying flow rates is detailed. Reaction takes place in a long cylindrical borosilicate glass tube of diameter 2.50 mm. Separation of product mixture takes place in an enlarged tube of diameter 5.50 mm. Various two phase flow patterns formed after decomposition reactions are identified by images captured using high speed camera. Length of oxygen slug formed after catalytic reaction is measured by employing Image processing techniques.
DOI: 10.6084/m9.figshare.7512005.v1
title: Mini-channel Two Phase Flow of Hydrogen Peroxide: Decomposition with Silver Catalyst

description: ABSTRACT Hydrogen peroxide is a chemical compound which is commonly used as a disinfectant at lower concentrations. The chemical is called as a green propellant for space applications. Water and oxygen are the products after self-decomposition of the compound at higher concentrations. The reaction rate at lower concentrations can be enhanced by using catalysts for faster reaction rates. In the present study, an experimental analysis of the reaction rate of hydrogen peroxide (6% by volume) with silver catalyst for varying flow rates is detailed. Reaction takes place in a long cylindrical borosilicate glass tube of diameter 2.50 mm. Separation of product mixture takes place in an enlarged tube of diameter 5.50 mm. Various two phase flow patterns formed after decomposition reactions are identified by images captured using high speed camera. Length of oxygen slug formed after catalytic reaction is measured by employing Image processing techniques.
DOI: 10.6084/m9.figshare.7519031.v1
title: Fast Densification Process in Manufacturing Carbon/Carbon Using Vegetable Precursors

description: ABSTRACT: The carbon/carbon composite manufacturing processes generally use flammable and toxic precursors. In order to make these processes safer, it is interesting to use less toxic and safer precursors to the environment and people. The present study investigates the types of pyrocarbon resulting from composite carbon/carbon densification produced by the technique of Film Boiling Chemical Vapor Infiltration using as carbon precursors: soybean oil, ethanol and hexane, the latter as control. The microstructure produced was analyzed through SEM techniques, PLOM, XRD and Raman. The pyrocarbons observed are Smooth Laminar, Rought Laminar and Regenerative Laminar types. Soybean oil resulted in porous bodies while other precursors resulted in denser bodies. The crystallites made with ethanol and hexane have preferential growth in the c direction, while those made with soybean oil grow preferentially in a direction.
DOI: 10.6084/m9.figshare.7507166
title: NUTRIENTS INTAKE AND DIGESTIBILITY OF PALM KERNEL CAKE IN SHEEP DIET

description: The aim of this study was to find the optimum inclusion level of palm kernel cake in sheep diet. We used 18 castrated rams, fed diets with inclusion levels of palm kernel cake of 0%, 7.5%, 15% and 22.5% of the total diet. Animals were housed in metabolic cages for 21 days. Data were subjected to regression study with 5% significance for equations and regression coefficients. The inclusion of palm kernel cake caused reduction in DM, hemicellulose, NDF, CP, TDN, TC and MM (P &lt;0.01) and no significant differences in cellulose, ADF and NFC (P&gt; 0.05). The intake of EE and lignin increased (P&lt;0.01). The fiber content of the diets added to the consumption of lignin by the animals caused reduction in digestibility of GE and all analyzed nutrients (DM, CP, hemicellulose, NDF; P&gt;0.05). There was reduction in metabolizability of the diets due to increased GE of feces (P &lt;0.01). Nitrogen balance was positive in all treatments. The inclusion of palm kernel cake above 7.5% in sheep diet causes reduction in DMI and digestibility of nutrients with possible performance losses, especially in high-performance animals.
DOI: 10.6084/m9.figshare.7511654.v1
title: A Comparative Study of the Heat Input During Laser Welding of Aeronautical Aluminum Alloy AA6013-T4

description: ABSTRACT The heat input is the amount of energy supplied per unit length of the welded workpiece. In this study, the effect of two different heat inputs in laser beam welding of a high strength aluminum alloy AA6013-T4 was evaluated from macrostructural and microstructural points of view. The experiments were performed using a continuous wave 2 kW Yb-fiber laser with 100 µm spot size on the upper surface of the workpiece. Keeping the heat input at a given level, 13 or 30 J/mm, the laser power was changed from 650 W to 2 kW and the welding speed from 33 to 150 mm/s. In the condition of higher heat input 30 J/mm it was possible to obtain both cutting and welding processes. For 13 J/mm, welding processes were obtained in conduction and keyhole modes. The equiaxed grain fraction changed with changing speed for the same heat input. The laser processing induced a decrease in the hardness of the weld bead of about 25% due to the solubilization of the precipitates. The estimated absorptivities of the laser beam in the liquid aluminum changed largely with experimental conditions, from 4.6% to 10.5%, being the most significant source of error in measuring the real amount of energy absorbed in the process. For the same heat input the macrostructure of the welded surfaces, i.e., humps and dropouts, changed as well. All these facts indicate that the heat input is not a convenient method to parameterize the laser beam welding parameters aiming the same weld features.
DOI: 10.6084/m9.figshare.7519031
title: Fast Densification Process in Manufacturing Carbon/Carbon Using Vegetable Precursors

description: ABSTRACT: The carbon/carbon composite manufacturing processes generally use flammable and toxic precursors. In order to make these processes safer, it is interesting to use less toxic and safer precursors to the environment and people. The present study investigates the types of pyrocarbon resulting from composite carbon/carbon densification produced by the technique of Film Boiling Chemical Vapor Infiltration using as carbon precursors: soybean oil, ethanol and hexane, the latter as control. The microstructure produced was analyzed through SEM techniques, PLOM, XRD and Raman. The pyrocarbons observed are Smooth Laminar, Rought Laminar and Regenerative Laminar types. Soybean oil resulted in porous bodies while other precursors resulted in denser bodies. The crystallites made with ethanol and hexane have preferential growth in the c direction, while those made with soybean oil grow preferentially in a direction.
DOI: 10.6084/m9.figshare.7710809
title: High concentrations of toxic metals in water consumed by the Maxakali indigenous community in Brazil

description: Abstract The Maxakali is the second largest indigenous population in the state of Minas Gerais, Brazil; and parasitic diseases are its main cause of death. Problems related to the quality of water consumed by this population, added to the absence of public sanitation services, aggravate the risk of illnesses due to several water-borne pathologies. Thus, the main purpose of this paper was to evaluate the water quality consumed in natura by the Maxakali community, quantifying toxic metals in relation to the maximum values allowed by Brazilian law. A descriptive cross-sectional study was carried out with samples of water collected in surface- and groundwater in the Maxakali villages, including three seasonal periods. Villages with the greatest number of altered measures of metals in water were Aldeias Pradinho (100%) and Água Boa (92%). The smallest number of changes were found in Aldeias Verde and Rafael (27%). The metals that appeared in the largest number of collections with values higher than recommended were Iron (50%), followed by Arsenic (46%), Aluminum (36%), Cadmium (22%) and Mercury (20%), respectively. The study identified high concentrations of toxic metals in the water consumed by the Maxakali indigenous community in Brazil.