cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.5772063.v1
title: Study and characterization of epoxy resin composites in gel coat with different contents of inorganic fillers

description: ABSTRACT The gel coat epoxy resins used in mold lamination need to give the piece a high gloss and homogeneity, guaranteeing aesthetic quality and mechanical properties. In this way, the present work aimed to study the formulation of epoxy resin composites/inorganic fillers aiming at the improvement of physical and mechanical properties. A complete experimental design was carried out with three central points, totaling 11 formulations of epoxy gel coat composite, in which the influence of titanium dioxide (TiO2) (20, 45 and 70 phr), calcite (0, 20 and 40 phr) and barite (0, 20 and 40 phr) in the physical properties, density and drainage level and hardness. Considerable variations were observed in the properties of the composites with the modifications made in the formulations. It was verified in the experimental planning that the variable density was significant in relation to the three independent variables and not significant in the lack of fit, in this way, the model adequately represented the experimental behavior. For the variable hardness, the linear model did not satisfactorily describe the influence of the loads. According to the tests carried out, it was observed that with reduction of TiO2 characterized an increase in hardness, therefore, a reduction in density. On the other hand the baryta exerted a positive influence on the two properties and the calcite did not present significant influence. Regarding the level of runoff, the samples that presented the greatest amount of loads were the ones that performed best on this property. Finally, a new formulation was performed that was validated by the density model (60 parts TiO2, 30 parts calcite and 20 parts barite) that met the specifications.
DOI: 10.6084/m9.figshare.5772060
title: Elastic characterization of plywood used and reused in forms through impulse excitation

description: ABSTRACT The wood forms are the responsible elements in giving the desired shape to the fresh concrete and to provide protection against impacts and temperature variations in its curing process. Plywood sheets are the elements most used in building for this process. The reuse of the plates is common during the work - not exceeding 10 times. However, the material may have variation in its mechanical properties. The primary goal of this work was to experimentally determine the modulus of elasticity as a function of the amount of reuse of the plywood. The test used was a three-point bending, in which the modulus of elasticity was determined. During a work, the sending of samples for laboratory analysis requires time. Nevertheless, the construction company cannot wait such time to continue the execution of the construction. If the characteristics of the plywood could be determined quickly and practically, the service could have been done safely and quickly. The second goal was to present a non-destructive technique which fits this context, that is, the impulse excitation. The experimental design took three treatments and seven replicates per each treatment. The same samples for the impulse excitation test and the destructive trials were used. The results show that the moisture has little influence on the reuse of the forms, since the density has enough variation due to the loss of material during reuse. The modulus of elasticity has a decrease of 48% after the fifth reuse. The non-destructive test using impulse excitation is suitable for estimating the modulus of elasticity of concrete forms.
DOI: 10.6084/m9.figshare.5772060.v1
title: Elastic characterization of plywood used and reused in forms through impulse excitation

description: ABSTRACT The wood forms are the responsible elements in giving the desired shape to the fresh concrete and to provide protection against impacts and temperature variations in its curing process. Plywood sheets are the elements most used in building for this process. The reuse of the plates is common during the work - not exceeding 10 times. However, the material may have variation in its mechanical properties. The primary goal of this work was to experimentally determine the modulus of elasticity as a function of the amount of reuse of the plywood. The test used was a three-point bending, in which the modulus of elasticity was determined. During a work, the sending of samples for laboratory analysis requires time. Nevertheless, the construction company cannot wait such time to continue the execution of the construction. If the characteristics of the plywood could be determined quickly and practically, the service could have been done safely and quickly. The second goal was to present a non-destructive technique which fits this context, that is, the impulse excitation. The experimental design took three treatments and seven replicates per each treatment. The same samples for the impulse excitation test and the destructive trials were used. The results show that the moisture has little influence on the reuse of the forms, since the density has enough variation due to the loss of material during reuse. The modulus of elasticity has a decrease of 48% after the fifth reuse. The non-destructive test using impulse excitation is suitable for estimating the modulus of elasticity of concrete forms.
DOI: 10.6084/m9.figshare.5772057
title: Development of n+np+ solar cells in 100 µm thick silicon wafers

description: ABSTRACT In the solar cell production cost, the silicon wafer represents roughly 50 % of the final value of the device. To lower the costs, the reduction of the current wafer thickness from 180-200 µm to 100-120 µm has been proposed. Although the p-type silicon is used to manufacture solar cells, it is susceptible to degradation due to boron-oxygen interaction. The devices manufactured in n-type silicon wafers doped with phosphorus do not present such degradation and has the potential of achieving higher efficiencies due to the larger minority charge carrier lifetime. The aim of this work is to present the development of n+np+ solar cells fabricated in Cz silicon wafers 100 μm thick. Thin devices were manufactured with the n+np+ structure and compared to n+pp+ devices manufactured in standard thick wafers. The average efficiency of (14.6 ± 0.4) % was achieved and the most efficient device reached 15.3%. The efficiency was lower than obtained with n+pp+ thick devices, which presented 16.2 %. The main parameter that reduced the efficiency of thin cells was the fill factor, which reached a maximum value of 0.748. Although the efficiency reached by thin n-type devices was worse than thick p-type ones, the former achieved a low mass/power ratio of 1.5 g/W, which is approximately 53 % lower than that obtained from thick p-type devices.
DOI: 10.6084/m9.figshare.5772057.v1
title: Development of n+np+ solar cells in 100 µm thick silicon wafers

description: ABSTRACT In the solar cell production cost, the silicon wafer represents roughly 50 % of the final value of the device. To lower the costs, the reduction of the current wafer thickness from 180-200 µm to 100-120 µm has been proposed. Although the p-type silicon is used to manufacture solar cells, it is susceptible to degradation due to boron-oxygen interaction. The devices manufactured in n-type silicon wafers doped with phosphorus do not present such degradation and has the potential of achieving higher efficiencies due to the larger minority charge carrier lifetime. The aim of this work is to present the development of n+np+ solar cells fabricated in Cz silicon wafers 100 μm thick. Thin devices were manufactured with the n+np+ structure and compared to n+pp+ devices manufactured in standard thick wafers. The average efficiency of (14.6 ± 0.4) % was achieved and the most efficient device reached 15.3%. The efficiency was lower than obtained with n+pp+ thick devices, which presented 16.2 %. The main parameter that reduced the efficiency of thin cells was the fill factor, which reached a maximum value of 0.748. Although the efficiency reached by thin n-type devices was worse than thick p-type ones, the former achieved a low mass/power ratio of 1.5 g/W, which is approximately 53 % lower than that obtained from thick p-type devices.
DOI: 10.6084/m9.figshare.5772054
title: Expansion evaluation of a soil of the municipality of Paulista-PE improved with lime

description: ABSTRACT The volume variation of the expansive soils due to the change of water content causes socioeconomic and environmental damage to geotechnical engineering works. Two basic requirements are needed for a soil to exhibit expansiveness, one intrinsic and the other extrinsic. The first is related to the soil mineralogical com- position, texture and structure and the second with the behavior of climate, the volume and the movement of groundwater, the vegetation and the anthropic occupation. The addition of lime to the expansive soil im- proves the geotechnical properties of the mixture. The lime has physical-chemical interactions with the ex- pansive soil capable of stabilizing the volume variation. Several buildings under construction in the State of Pernambuco are located in areas of occurrence of expansive soils. The effect of lime treatment on the proper- ties of Paulista expansive soil was investigated, comparing the behavior of natural soil and soil mixed with lime in the proportions of 3%, 5%, and 7% by weight. Physical, chemical and mineralogical characterization tests (by thermogravimetry (TG) and X-ray diffractometry), free expansion and expansion stress were carried out. The natural soil presented high expansiveness. The determination of the expansion voltage was influ- enced by the voltage trajectory followed during the test. The addition of lime to the soil caused an aggrega- tion or flocculation of the particles and a reduction in the plasticity index. The addition of 5% of hydrated lime to the soil of Paulista stabilized in relation to the free expansion and the expansion tension.
DOI: 10.6084/m9.figshare.5772054.v1
title: Expansion evaluation of a soil of the municipality of Paulista-PE improved with lime

description: ABSTRACT The volume variation of the expansive soils due to the change of water content causes socioeconomic and environmental damage to geotechnical engineering works. Two basic requirements are needed for a soil to exhibit expansiveness, one intrinsic and the other extrinsic. The first is related to the soil mineralogical com- position, texture and structure and the second with the behavior of climate, the volume and the movement of groundwater, the vegetation and the anthropic occupation. The addition of lime to the expansive soil im- proves the geotechnical properties of the mixture. The lime has physical-chemical interactions with the ex- pansive soil capable of stabilizing the volume variation. Several buildings under construction in the State of Pernambuco are located in areas of occurrence of expansive soils. The effect of lime treatment on the proper- ties of Paulista expansive soil was investigated, comparing the behavior of natural soil and soil mixed with lime in the proportions of 3%, 5%, and 7% by weight. Physical, chemical and mineralogical characterization tests (by thermogravimetry (TG) and X-ray diffractometry), free expansion and expansion stress were carried out. The natural soil presented high expansiveness. The determination of the expansion voltage was influ- enced by the voltage trajectory followed during the test. The addition of lime to the soil caused an aggrega- tion or flocculation of the particles and a reduction in the plasticity index. The addition of 5% of hydrated lime to the soil of Paulista stabilized in relation to the free expansion and the expansion tension.
DOI: 10.6084/m9.figshare.5772051
title: Efficacy and safety of Elevate® system on apical and anterior compartment prolapse repair with personal technique modification

description: ABSTRACT Aim: To evaluate the effectiveness and safety of Anterior Elevate® mesh kit system (AES) in woman with symptomatic stage 3 or 4 anterior and/or apical pelvic organ prolapse (POP). Materials and Methods: This retrospective, monocentric, single surgeon study enrolled between May 2010 and January 2013 fifty-six woman experiencing symptomatic anterior vaginal prolapse with or without apical descent (POP-Q stage 3 or 4). All women received a AES and 7 (12.5%) received a concomitant transvaginal hysterectomy. Primary endpoint was anatomic correction of prolapse; success was defined as POP-Q stage ≤ 1 or asymptomatic stage 2. Secondary endpoints were quality-of-life (QOL) results and patients' safety outcomes, which were assessed by 3 validated self-reporting questionnaires at baseline and annually: ICIQ-UI short form, ICIQ-VS and P-QOL. All patients completed 2-years and 28 women 3-years of follow-up. Surgical approach was modified in women with uterus, moving the two-propylene strips anteriorly around the cervix itself crossing one another, so the left will take place in the right side and the right on the opposite. This modification was made in order to better support the uterus. Results: Vaginal mesh exposure was present in 3 (5,3%) patients. Very good anatomical outcomes were seen, with one (1,8%) failure at 6-months, 4 (7,1%) at 1-year, 6 at 2-years (10,7%). Statistically significant improvements were seen in the ICIQ-VS and P-QOL questionnaires throughout follow-up. Conclusion: Our data suggest that AES is a minimally-invasive transvaginal procedure to repair anterior and apical POP, with good evidence related to mid-term safety and efficacy.
DOI: 10.6084/m9.figshare.5772051.v1
title: Efficacy and safety of Elevate® system on apical and anterior compartment prolapse repair with personal technique modification

description: ABSTRACT Aim: To evaluate the effectiveness and safety of Anterior Elevate® mesh kit system (AES) in woman with symptomatic stage 3 or 4 anterior and/or apical pelvic organ prolapse (POP). Materials and Methods: This retrospective, monocentric, single surgeon study enrolled between May 2010 and January 2013 fifty-six woman experiencing symptomatic anterior vaginal prolapse with or without apical descent (POP-Q stage 3 or 4). All women received a AES and 7 (12.5%) received a concomitant transvaginal hysterectomy. Primary endpoint was anatomic correction of prolapse; success was defined as POP-Q stage ≤ 1 or asymptomatic stage 2. Secondary endpoints were quality-of-life (QOL) results and patients' safety outcomes, which were assessed by 3 validated self-reporting questionnaires at baseline and annually: ICIQ-UI short form, ICIQ-VS and P-QOL. All patients completed 2-years and 28 women 3-years of follow-up. Surgical approach was modified in women with uterus, moving the two-propylene strips anteriorly around the cervix itself crossing one another, so the left will take place in the right side and the right on the opposite. This modification was made in order to better support the uterus. Results: Vaginal mesh exposure was present in 3 (5,3%) patients. Very good anatomical outcomes were seen, with one (1,8%) failure at 6-months, 4 (7,1%) at 1-year, 6 at 2-years (10,7%). Statistically significant improvements were seen in the ICIQ-VS and P-QOL questionnaires throughout follow-up. Conclusion: Our data suggest that AES is a minimally-invasive transvaginal procedure to repair anterior and apical POP, with good evidence related to mid-term safety and efficacy.
DOI: 10.6084/m9.figshare.5772048
title: Natural corrosion inhibitors - Proposal to obtain ecological products of low cost from industrial waste

description: ABSTRACT The corrosion inhibitors are obtained from natural plant extracts or biodegradable material, and cause a reduction in the intensity of dissolution of metals by lowering their corrosion. Research conducted in recent years report that many plants have, in their constitution, compounds with antioxidant activity, mainly polyphenols. This paper will present the history of the development of natural inhibitors from fruit extracts for application in neutral and acid media carried out in Labcorr / COPPE / UFRJ. The orange peel, mango peel, passion fruit peel, cashew peel, papaya seed and grape pomace extracts were analyzed. The extracts were obtained by three different extraction methodologies: infusion extraction, polarity gradient extraction and hydroalcohol extraction. The inhibition efficiencies of the extracts tested were obtained by weight- loss tests. The neutral medium studied simulates the composition of water of industrial cooling systems with high concentration cycle, with 1050 ppm of chloride, 450 ppm of calcium and 160 ppm of bicarbonate and pH 7.5. The performance of extracts was good in both media studied. The concentrated grape pomace extracts had the best inhibition efficiency in the weight-loss tests with a period of 72 hours of immersion in neutral medium, whose value was of 74%. The efficiency of these inhibitors was more significant in 1 mol·L-1 hydrochloric acid media, with efficiencies above 93% in a period of 24 hours of immersion.
DOI: 10.6084/m9.figshare.5772048.v1
title: Natural corrosion inhibitors - Proposal to obtain ecological products of low cost from industrial waste

description: ABSTRACT The corrosion inhibitors are obtained from natural plant extracts or biodegradable material, and cause a reduction in the intensity of dissolution of metals by lowering their corrosion. Research conducted in recent years report that many plants have, in their constitution, compounds with antioxidant activity, mainly polyphenols. This paper will present the history of the development of natural inhibitors from fruit extracts for application in neutral and acid media carried out in Labcorr / COPPE / UFRJ. The orange peel, mango peel, passion fruit peel, cashew peel, papaya seed and grape pomace extracts were analyzed. The extracts were obtained by three different extraction methodologies: infusion extraction, polarity gradient extraction and hydroalcohol extraction. The inhibition efficiencies of the extracts tested were obtained by weight- loss tests. The neutral medium studied simulates the composition of water of industrial cooling systems with high concentration cycle, with 1050 ppm of chloride, 450 ppm of calcium and 160 ppm of bicarbonate and pH 7.5. The performance of extracts was good in both media studied. The concentrated grape pomace extracts had the best inhibition efficiency in the weight-loss tests with a period of 72 hours of immersion in neutral medium, whose value was of 74%. The efficiency of these inhibitors was more significant in 1 mol·L-1 hydrochloric acid media, with efficiencies above 93% in a period of 24 hours of immersion.
DOI: 10.6084/m9.figshare.5772045
title: Determination of modulus of elasticity of wood depending on the inclination of fibers using acoustic tomography

description: ABSTRACT The objectives of this work are to determine, from non-destructive tests, the modulus of elasticity as a function of the inclination of the wood fibers through an acoustic tomograph, to compare and discuss the application of six fault criteria adapted for non destructive tests and to modify the formulas for to determine the most suitable failure criteria for the proposed non-destructive test. To determine the most suitable failure criteria for the proposed non-destructive test. For this, 6 specimens of 150x15x4 cm of 6 species of wood were tested. An acoustic tomograph with eight transducers was used. These sensors are fixed and mechanically excited with a hammer. Each time a sensor is excited the others capture the time the mechanical wave took to arrive, then the speed is determined and the modulus of elasticity is calculated. The inclination of the fibers is determined from the angles formed by each transducer in relation to the direction thereof. The experimental results were compared with six theories of mechanical rupture criteria. It is concluded that it is possible to use the acoustic tomograph to determine the modulus of elasticity inclined to the fibers, with only one experimental test. All six mathematical models evaluated do not present statistical significance in their original format. With the modifications made in the models those that presented significance were only the models: hyperbolic, Karlsen and Hankinson, therefore they are the most indicated to estimate the values of the modulus of elasticity as a function of the inclination of the fibers.
DOI: 10.6084/m9.figshare.5772045.v1
title: Determination of modulus of elasticity of wood depending on the inclination of fibers using acoustic tomography

description: ABSTRACT The objectives of this work are to determine, from non-destructive tests, the modulus of elasticity as a function of the inclination of the wood fibers through an acoustic tomograph, to compare and discuss the application of six fault criteria adapted for non destructive tests and to modify the formulas for to determine the most suitable failure criteria for the proposed non-destructive test. To determine the most suitable failure criteria for the proposed non-destructive test. For this, 6 specimens of 150x15x4 cm of 6 species of wood were tested. An acoustic tomograph with eight transducers was used. These sensors are fixed and mechanically excited with a hammer. Each time a sensor is excited the others capture the time the mechanical wave took to arrive, then the speed is determined and the modulus of elasticity is calculated. The inclination of the fibers is determined from the angles formed by each transducer in relation to the direction thereof. The experimental results were compared with six theories of mechanical rupture criteria. It is concluded that it is possible to use the acoustic tomograph to determine the modulus of elasticity inclined to the fibers, with only one experimental test. All six mathematical models evaluated do not present statistical significance in their original format. With the modifications made in the models those that presented significance were only the models: hyperbolic, Karlsen and Hankinson, therefore they are the most indicated to estimate the values of the modulus of elasticity as a function of the inclination of the fibers.
DOI: 10.6084/m9.figshare.5772039
title: Study of NiO-GDC material produced by aqueous tape casting

description: ABSTRACT Studies have been developed in last decades in order to produce NiO-based material to be used as anode in solid oxide fuel cell (SOFC). Aqueous-based tape casting was used to produce NiO-GDC substrates with smooth and homogeneous surfaces and good flexibility. Physical and mechanical properties were obtained in green tapes sintered at temperatures ranging from 1200 to 1400 ͦ C. The tapes sintered in 1400 ͦ C showed the best density and porosity values and mechanical strength between 7 and 25 MPa. SEM micrographs show a dense material with cracks and pores. The sintered material shows the presence of nickel oxide and gadolinium cerium oxide.
DOI: 10.6084/m9.figshare.5772039.v1
title: Study of NiO-GDC material produced by aqueous tape casting

description: ABSTRACT Studies have been developed in last decades in order to produce NiO-based material to be used as anode in solid oxide fuel cell (SOFC). Aqueous-based tape casting was used to produce NiO-GDC substrates with smooth and homogeneous surfaces and good flexibility. Physical and mechanical properties were obtained in green tapes sintered at temperatures ranging from 1200 to 1400 ͦ C. The tapes sintered in 1400 ͦ C showed the best density and porosity values and mechanical strength between 7 and 25 MPa. SEM micrographs show a dense material with cracks and pores. The sintered material shows the presence of nickel oxide and gadolinium cerium oxide.