cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.6857531.v1
title: Treatment of aqueous effluents from the biodiesel industry using membrane technology

description: ABSTRACT The wastewaters from biodiesel production are generated mainly in the washing process, in this step the contaminants of biodiesel are eliminated in order to the obtained biodiesel meets with the internationals regulations. These wastes contain impurities such as methyl ester, residual oil, mono and diglycerides, soluble salts, catalyst, soap, glycerol and alcohol. The aim of this study is the application of membrane technology for the treatment of aqueous wastes from biodiesel industry. By means of the phase inversion method was synthesized a membrane of UF using a 17wt% of polyvinylidene polyfluoride (PVDF) and 8,5wt % polyvinylpyrrolidone (PVP) casting solution. The filtration essays were performed in a cross flow cell. The operational conditions were: T= 20°C, Δp=0.4-1 bar y v=0.5-1 m/s. A synthetic sample prepared in the laboratory and a real effluent sample from biodiesel industry was employed as membrane feed. At constant feed stream speed, the permeate flux decreases with increase of pressure (mass transfer controlled region). While an increasing in the permeation speed at constant pressure the permeate flux gradually increases. With increasing speed, membrane surface cleaning increases due to solutes are swept tangentially away. It was concluded that the studied membrane retains between 83-100% of oils and fats, and between 20-40% of DQO, whereas pH and TSS remain constant.
DOI: 10.6084/m9.figshare.6857522
title: Endozoochorous dispersal of seeds of weedy rice (Oryza sativa L.) and barnyardgrass (Echinochloa crus-galli L.) by cattle

description: ABSTRACT: The objective of this study was to evaluate endozoochory dispersal, recuperation, and germination of weedy rice (Oryza sativa L.) and barnyardgrass (Echinochloa crus-galli L.) seeds passed through the digestive system of cattle. The experiment was divided into two phases: first, the daily seed recuperation rate was determined after passing through the digestive system of six steers. Each animal was dosed individually with 1000 weedy rice seeds and 13,818 barnyardgrass seeds, and these seeds were subsequently collected from feces. In the second phase, seed germination and emergence rate after passing or not passing through the digestive system of cattle were determined in two types of substrates (fecal plaque and soil) in a 2×2 factorial design. Seed recuperation in feces showed sigmoid behavior with maximum recovery on the second day after dosage. The recuperation of the species in the feces was 50.9% and 23.4% for weedy rice and barnyardgrass, respectively, which shows that both have potential endozoochory dispersal. However, seed germination of these species reduced after they passed through the digestive system, and they presented inferior emergence in the fecal plaque compared to the soil. The quarantine period for animals that ingest weedy rice and barnyardgrass seeds should be at least 6 and 7 days, respectively.
DOI: 10.6084/m9.figshare.6857525
title: Fatigue life of PAW welded joints of high strength microalloyed boron steels

description: ABSTRACT In the last years microalloyed boron steels have been adopted in the automotive industry to achieve weight reductions. Namely, they are used as load-bearing elements such as pillars and reinforcements, in a quenched and tempered (QT) condition with tensile strength ranging from 800 to 1300 MPa. Dual-Phase (DP) steels have also been introduced in this industry given their good combination of high strength and ductility, coupled with good energy absorption characteristics. The automobile is largely a welded steel frame construction. Thus, the weldability of these advanced high strength steels is a key aspect. The Plasma Arc Welding process (PAW) presents features that make it suitable for these applications. Furthermore, the mechanical response, specifically the fatigue behavior of weldments is crucial for this kind of applications. In this manner, the purpose of this work was to study the fatigue response of PAW welded joints of 1mm high strength (900 MPa) microalloyed boron steels sheets in two microstructural conditions: quenched and tempered (QT) and dualphase (DP). Intercritical and quenching and tempering heat treatments were performed. Coupons of 100x100mm were welded by PAW and characterized. Finally, by means of pulsating 4-point bending fatigue tests, fatigue curves were obtained for both types of welded joints (PAW+TR and PAW+DP). A superior fatigue life was measured for de PAW+DP samples. This observation could be related to the different microstructural evolution experienced in the heat affected zone of this two materials.
DOI: 10.6084/m9.figshare.6857519
title: Formation of the PNAIC in Geometry and the Educational Trajectory of the Literacy Teachers

description: Abstract In this work, we present the educational trajectory of five literacy teachers regarding the learning in Geometry and how, after they participated in the continuous formation of these concepts based on the National Pact of Literacy in the Right Age (PNAIC), they elaborated their teaching strategies and evaluated this course. This work, which is of a qualitative character, had semi-structured interviews and field notes elaborated during class observations as instruments of data collection. For the analysis, we used methodologies resulting from the French Line of the Discourse Analysis aiming to understand the production conditions in which these subjects are situated. Our results showed that there was a conceptual gap in the formation of these participants, and the discourses indicated that they were influenced by the abandonment or minimization of geometric concepts, affecting how they currently understand and elaborate their teaching work in relation to this topic.
DOI: 10.6084/m9.figshare.6857522.v1
title: Endozoochorous dispersal of seeds of weedy rice (Oryza sativa L.) and barnyardgrass (Echinochloa crus-galli L.) by cattle

description: ABSTRACT: The objective of this study was to evaluate endozoochory dispersal, recuperation, and germination of weedy rice (Oryza sativa L.) and barnyardgrass (Echinochloa crus-galli L.) seeds passed through the digestive system of cattle. The experiment was divided into two phases: first, the daily seed recuperation rate was determined after passing through the digestive system of six steers. Each animal was dosed individually with 1000 weedy rice seeds and 13,818 barnyardgrass seeds, and these seeds were subsequently collected from feces. In the second phase, seed germination and emergence rate after passing or not passing through the digestive system of cattle were determined in two types of substrates (fecal plaque and soil) in a 2×2 factorial design. Seed recuperation in feces showed sigmoid behavior with maximum recovery on the second day after dosage. The recuperation of the species in the feces was 50.9% and 23.4% for weedy rice and barnyardgrass, respectively, which shows that both have potential endozoochory dispersal. However, seed germination of these species reduced after they passed through the digestive system, and they presented inferior emergence in the fecal plaque compared to the soil. The quarantine period for animals that ingest weedy rice and barnyardgrass seeds should be at least 6 and 7 days, respectively.
DOI: 10.6084/m9.figshare.6857525.v1
title: Fatigue life of PAW welded joints of high strength microalloyed boron steels

description: ABSTRACT In the last years microalloyed boron steels have been adopted in the automotive industry to achieve weight reductions. Namely, they are used as load-bearing elements such as pillars and reinforcements, in a quenched and tempered (QT) condition with tensile strength ranging from 800 to 1300 MPa. Dual-Phase (DP) steels have also been introduced in this industry given their good combination of high strength and ductility, coupled with good energy absorption characteristics. The automobile is largely a welded steel frame construction. Thus, the weldability of these advanced high strength steels is a key aspect. The Plasma Arc Welding process (PAW) presents features that make it suitable for these applications. Furthermore, the mechanical response, specifically the fatigue behavior of weldments is crucial for this kind of applications. In this manner, the purpose of this work was to study the fatigue response of PAW welded joints of 1mm high strength (900 MPa) microalloyed boron steels sheets in two microstructural conditions: quenched and tempered (QT) and dualphase (DP). Intercritical and quenching and tempering heat treatments were performed. Coupons of 100x100mm were welded by PAW and characterized. Finally, by means of pulsating 4-point bending fatigue tests, fatigue curves were obtained for both types of welded joints (PAW+TR and PAW+DP). A superior fatigue life was measured for de PAW+DP samples. This observation could be related to the different microstructural evolution experienced in the heat affected zone of this two materials.
DOI: 10.6084/m9.figshare.6857516
title: Electrochemical corrosion characterization of nickel aluminides in acid rain

description: ABSTRACT Nickel aluminides have been extensively studied in recent decades to replace superalloys, in some components of aircraft turbines, because they have excellent corrosion resistance. Many industrial cities have the problem of air pollution, which has forced the study of the degradation of these alloys in the presence of acid rain. The aim of this work is to study the electrochemical corrosion behavior of nickel aluminides in a medium of simulated acid rain. Potentiodynamic Polarization, Linear polarization resistance curves, Rp, Nyquist data and Bode curves obtained by electrochemical impedance spectroscopy were used to study the corrosion behavior of two intermetallic compounds. The polarization curves show that both intermetallic Ni3Al and NiAl have very similar corrosion potential, showing a slightly nobler behavior the NiAl intermetallic. The intermetallic Ni3Al has an active-passive behavior where the anode branch presents a general dissolution of the alloy, indicating that it is under cathodic control. NiAl intermetallic shows an active dissolution region, followed by a passive behavior. At longer immersion times, Ni3Al intermetallic has a higher polarization resistance, which means a lower corrosion rate.
DOI: 10.6084/m9.figshare.6857519.v1
title: Formation of the PNAIC in Geometry and the Educational Trajectory of the Literacy Teachers

description: Abstract In this work, we present the educational trajectory of five literacy teachers regarding the learning in Geometry and how, after they participated in the continuous formation of these concepts based on the National Pact of Literacy in the Right Age (PNAIC), they elaborated their teaching strategies and evaluated this course. This work, which is of a qualitative character, had semi-structured interviews and field notes elaborated during class observations as instruments of data collection. For the analysis, we used methodologies resulting from the French Line of the Discourse Analysis aiming to understand the production conditions in which these subjects are situated. Our results showed that there was a conceptual gap in the formation of these participants, and the discourses indicated that they were influenced by the abandonment or minimization of geometric concepts, affecting how they currently understand and elaborate their teaching work in relation to this topic.
DOI: 10.6084/m9.figshare.6857513
title: Movement of the interphases during the horizontal solidification of tin-zinc alloys

description: ABSTRACT Solidification processing is one of the important routes to produce materials, especially metals and alloys. The parameters for the transformation from liquid to solid, such as the temperature gradient, the growth rate, the cooling rate, the interphase velocity, vary from process to process and in one process also as a function of time and space. These variations together with the different alloy compositions, lead to a multitude of microstructures and therefore, affect the behavior of the material. In this work the evolution of the interphases is studied in Sn-Zn (Sn-6wt.% Zn (hypoeutectic) and Sn-15wt.% Zn (hypereutectic)) when the specimens were unidirectionally horizontally solidified through heat extraction in two opposite directions. Sn-Zn specimens shaped in cylindrical segments were obtained, with an average length between 13 cm-17 cm, an average width between 3 cm-3.2 cm and an average thickness of 0.8 cm – 1.2 cm, depending on the experience. The thermal parameters (cooling rates, temperature gradients, positions and velocities of the present interfaces) were determined and related to the final structures resulting from the solidification. It was found that the value of the velocity of the interphase is maximum when opposing fronts of solidification collide, advancing in opposite directions in the specimens. The values were superior to 2 mm/s for both analyzed Sn-Zn alloys.
DOI: 10.6084/m9.figshare.6857516.v1
title: Electrochemical corrosion characterization of nickel aluminides in acid rain

description: ABSTRACT Nickel aluminides have been extensively studied in recent decades to replace superalloys, in some components of aircraft turbines, because they have excellent corrosion resistance. Many industrial cities have the problem of air pollution, which has forced the study of the degradation of these alloys in the presence of acid rain. The aim of this work is to study the electrochemical corrosion behavior of nickel aluminides in a medium of simulated acid rain. Potentiodynamic Polarization, Linear polarization resistance curves, Rp, Nyquist data and Bode curves obtained by electrochemical impedance spectroscopy were used to study the corrosion behavior of two intermetallic compounds. The polarization curves show that both intermetallic Ni3Al and NiAl have very similar corrosion potential, showing a slightly nobler behavior the NiAl intermetallic. The intermetallic Ni3Al has an active-passive behavior where the anode branch presents a general dissolution of the alloy, indicating that it is under cathodic control. NiAl intermetallic shows an active dissolution region, followed by a passive behavior. At longer immersion times, Ni3Al intermetallic has a higher polarization resistance, which means a lower corrosion rate.
DOI: 10.6084/m9.figshare.6857510
title: Time-dependent methods for limit strains determination of sheet metal

description: ABSTRACT The forming limit diagram (FLD) –broadly used to characterize sheet-metal formability– is made by means of strain measurement over the surface of stretched samples and the subsequent determination of limit-strain values associated with the onset of necking. Currently, researchers can make strain measurements with digital image-correlation analysis (DIC). Data measured by DIC easily adapt to the traditional position-dependent method for evaluating limit strains, but this method is not applicable to materials that exhibit inhomogeneous deformation, like multiple necking. DIC analysis allows for the application of time-dependent methods, which are based on analysis of the temporal evolution of strains to define the onset of necking. This article compares three recently proposed time-dependent techniques for determining limit strains: a thickness-control method, the strain-control method and an acceleration-correlation method. For experimental purposes, duplex 2205 stainless-steel sheet, 0.92mm thick, was tested in uniaxial tension. The standard position-dependent method (ISO 12004-2) provides a reference for comparing results. We attribute differences in limit-strain values to the difficulty in objectively setting each method’s parameters. These differences show that there are still aspects of the temporal analyses that must be improved on before a precise and generalized methodology is available.
DOI: 10.6084/m9.figshare.6857510.v1
title: Time-dependent methods for limit strains determination of sheet metal

description: ABSTRACT The forming limit diagram (FLD) –broadly used to characterize sheet-metal formability– is made by means of strain measurement over the surface of stretched samples and the subsequent determination of limit-strain values associated with the onset of necking. Currently, researchers can make strain measurements with digital image-correlation analysis (DIC). Data measured by DIC easily adapt to the traditional position-dependent method for evaluating limit strains, but this method is not applicable to materials that exhibit inhomogeneous deformation, like multiple necking. DIC analysis allows for the application of time-dependent methods, which are based on analysis of the temporal evolution of strains to define the onset of necking. This article compares three recently proposed time-dependent techniques for determining limit strains: a thickness-control method, the strain-control method and an acceleration-correlation method. For experimental purposes, duplex 2205 stainless-steel sheet, 0.92mm thick, was tested in uniaxial tension. The standard position-dependent method (ISO 12004-2) provides a reference for comparing results. We attribute differences in limit-strain values to the difficulty in objectively setting each method’s parameters. These differences show that there are still aspects of the temporal analyses that must be improved on before a precise and generalized methodology is available.
DOI: 10.6084/m9.figshare.6857513.v1
title: Movement of the interphases during the horizontal solidification of tin-zinc alloys

description: ABSTRACT Solidification processing is one of the important routes to produce materials, especially metals and alloys. The parameters for the transformation from liquid to solid, such as the temperature gradient, the growth rate, the cooling rate, the interphase velocity, vary from process to process and in one process also as a function of time and space. These variations together with the different alloy compositions, lead to a multitude of microstructures and therefore, affect the behavior of the material. In this work the evolution of the interphases is studied in Sn-Zn (Sn-6wt.% Zn (hypoeutectic) and Sn-15wt.% Zn (hypereutectic)) when the specimens were unidirectionally horizontally solidified through heat extraction in two opposite directions. Sn-Zn specimens shaped in cylindrical segments were obtained, with an average length between 13 cm-17 cm, an average width between 3 cm-3.2 cm and an average thickness of 0.8 cm – 1.2 cm, depending on the experience. The thermal parameters (cooling rates, temperature gradients, positions and velocities of the present interfaces) were determined and related to the final structures resulting from the solidification. It was found that the value of the velocity of the interphase is maximum when opposing fronts of solidification collide, advancing in opposite directions in the specimens. The values were superior to 2 mm/s for both analyzed Sn-Zn alloys.
DOI: 10.6084/m9.figshare.6857504
title: Comparative study of U diffusion in Zry-4 and pure α-Zr

description: ABSTRACT Throughout the α-spectrometry U diffusion in pure Zry-4 was studied and compared with pure α-Zr in the temperature range 843-1093 K in order to analyze the diffusion process in both matrices. D values are systematically higher in Zry-4 and its temperature dependence obeys the Arrhenius law being: D0 = (3,2 ± 1,1) m2/s and Q = (316 ± 9) kJ mol-1, whereas in α-Zr U diffusion present an apart to this law, consistent in a downward curvature in the ln(D) vs 1/T plot. Below 873 K U solubility in Zry4 is lower than in pure Zr.
DOI: 10.6084/m9.figshare.6857507
title: Copper-Aluminothermic weld characterization on line pipes for cathodic protection

description: ABSTRACT Copper-Aluminothermic weld is a process in which welder is generated by thermofusion. The necessary heat is obtained by the aluminum reducing effect above copper oxide, creating a high temperature exothermic reaction, in which melt and overheated copper is the filler material [1].This technique is used to joint rails in railway industry, in grounding welds [2, 3] and also in linepipes for cathodic protection. In this study copperaluminothermic weld is characterized for API 5L X46 and X52 steel linepipes for cathodic protection, considering two different thickness, changing the copper wire section and the flux amount. The purpose is to obtain the optimum welding conditions, therefore macroscopic and microscopic tests, and microhardness sweep are going to be performed on the heat affected zone. Twenty-five test tubes were realized, taking also into account different flux and gunpowder brands and melting pot sizes. An inadequate contact area can cause lack of pipe cathodic protection as well as an excessive copper diffusion into the grain boundaries can produce accelerated corrosion and microcracks in the base metal [4,1], for that reason is necessary to obtain optimum welding conditions according to the steel grade and pipe thickness.
DOI: 10.6084/m9.figshare.6857507.v1
title: Copper-Aluminothermic weld characterization on line pipes for cathodic protection

description: ABSTRACT Copper-Aluminothermic weld is a process in which welder is generated by thermofusion. The necessary heat is obtained by the aluminum reducing effect above copper oxide, creating a high temperature exothermic reaction, in which melt and overheated copper is the filler material [1].This technique is used to joint rails in railway industry, in grounding welds [2, 3] and also in linepipes for cathodic protection. In this study copperaluminothermic weld is characterized for API 5L X46 and X52 steel linepipes for cathodic protection, considering two different thickness, changing the copper wire section and the flux amount. The purpose is to obtain the optimum welding conditions, therefore macroscopic and microscopic tests, and microhardness sweep are going to be performed on the heat affected zone. Twenty-five test tubes were realized, taking also into account different flux and gunpowder brands and melting pot sizes. An inadequate contact area can cause lack of pipe cathodic protection as well as an excessive copper diffusion into the grain boundaries can produce accelerated corrosion and microcracks in the base metal [4,1], for that reason is necessary to obtain optimum welding conditions according to the steel grade and pipe thickness.
DOI: 10.6084/m9.figshare.6857501
title: Lecture capture and learner engagement strategies for industrial engineering distance education: results of a pilot program

description: Abstract Paper aims This study examines issues affecting the efficacy of online course delivery using lecture capture technology. This form of instruction presents particular challenges when classes are comprised of a mix of students who participate synchronously and asynchronously. Originality The study examines a pilot program focused on improving the delivery of lecture capture courses, providing a framework for the implementation of similar programs at other institutions. Research method Program feedback as to the quality of the learning experience is obtained from the instructor, as well as from both synchronous and asynchronous online learners. Main findings The results provide insights into how students engage with the instructor and with one another in a lecture capture setting. Effective instructional practices are also identified. Implications for theory and practice The results provide important insights that can enhance the delivery of courses utilizing lecture capture technology across a range of educational contexts.