cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.8260028.v1
title: Changing the characteristics of the nitrided layer using three different plasma configurations

description: ABSTRACT Direct current (DC) plasma nitriding offers some disadvantages, especially in parts with complex geometries, where the presence of edges is significant, such as gears, molds, and needle punched parts are strongly affected by this effect, leading to irregular formation of nitrided layers and high variation in surface hardness. To solve these problems two techniques were developed as alternatives, namely: pulsed plasma nitriding and cathodic cage nitriding. In this work, these three nitriding techniques were compared using AISI 1045 steel as substrate. Steel discs were nitrided with the purpose of evaluating the influence of these different plasma configurations on the characteristics of the nitrided layer. The treatments in the three techniques were carried out at the same pressure, temperature, time and gas atmosphere. The samples were characterized for the microstructure, microhardness and crystalline phases present. X-ray diffraction with grazing incidence was used to verify the order of the nitrites formed and to estimate the thickness of the single-phase layers. Differences between the configurations with respect to the occurrence of restriction rings, total thickness (xε +xγ') and relative (xε/xγ') compound layers were observed.
DOI: 10.6084/m9.figshare.8260019
title: Direct inhibitory effect of caffeine on viability, synthesis activity and gene expression in cultures of chondrocytes extracted from the articular cartilage of rats

description: ABSTRACT The aim of this study was to evaluate the effect of concentrations of caffeine on the viability, synthesis activity and gene expression in cultures of chondrocytes. Extracted articular cartilage from the femurs and tibias of 15 Wistar rats at three days old to isolate chondrocytes. Chondrocytes were cultured in chondrogenic medium (control) or supplemented with caffeine (0.5, 1.0, 2.0mM). Cell viability, alkaline phosphatase activity and collagen synthesis were assessed using colorimetric assays at 7, 14, 21 days. The chondrocyte cultures of all groups grown under coverslips were stained with hematoxylin-eosin to determine the percentage of cells/field and with PAS, safranin O, alcian blue to determine the percentage of matrix chondrogenic/field at 21 days. The expressions of gene transcripts for aggrecan, collagen-II, Sox-9, Runx-2 and alkaline phosphatase were also evaluated by RT-PCR at 21 days. The means were compared using Student-Newman-Keuls. Caffeine significantly reduced the conversion of MTT to formazan, percentage of cells/field, collagen synthesis, alkaline phosphatase activity, synthesis of PAS+, safranin O+ and alcian blue+ chondrogenic matrix, and the expression of aggrecan, Sox-9 and II collagen. It is concluded that caffeine at concentrations of 0.5, 1.0, 2.0mM has a direct inhibitory effect on chondrogenesis in cultures of chondrocytes from rats.
DOI: 10.6084/m9.figshare.8260022
title: Properties of concrete manufactured with use of ceramic sanitary ware waste as aggregate

description: ABSTRACT In concrete manufacture, cement (Portland type is the most used), water and aggregates (classified into coarse and fine) are used. With the use of several raw materials the generation of waste is inevitable, both in construction and in other sectors, such as the industries producing ceramic materials. Among the types of waste from such industries, can be mentioned the ceramic scrap (from the sanitary ware industry). According to the above, the aim of this research was to study the addition of ceramic scrap as a coarse aggregate in different proportions in the concrete formulation. In order to do this, was select wastes from an industry in the south of Minas Gerais (Brazil), and prepare specimens to determine the fresh (slump test, adhesiveness and porosity) and hardened (compression strength) of concrete. Were fabricated five concrete formulations, one reference (RC) and four with ceramic scrap substituted for coarse aggregate in the proportions of 25% (CSC-I), 50% (CSC-II), 75% (CSC-III) and 100% (CSC -IV). Fresh concretes, two formulations did not show adhesiveness (CSC-III and CSC-IV) and two a small water runoff (CSC-I and CSC-II), however, without compromising the concrete’s workability. Regarding the compression strength, the average values presented were very good, including the formulation with 100% ceramic scrap (fc = 47.78 MPa). Another important aspect observed in the rupture modes was the small adhesion between the ceramic scrap and the mortar due to the glazing in the contour of the waste. As for the porosity of the concretes, those with 25%, 75% and 100% of ceramic scrap in their composition presented lower values than the reference concrete.
DOI: 10.6084/m9.figshare.8260022.v1
title: Properties of concrete manufactured with use of ceramic sanitary ware waste as aggregate

description: ABSTRACT In concrete manufacture, cement (Portland type is the most used), water and aggregates (classified into coarse and fine) are used. With the use of several raw materials the generation of waste is inevitable, both in construction and in other sectors, such as the industries producing ceramic materials. Among the types of waste from such industries, can be mentioned the ceramic scrap (from the sanitary ware industry). According to the above, the aim of this research was to study the addition of ceramic scrap as a coarse aggregate in different proportions in the concrete formulation. In order to do this, was select wastes from an industry in the south of Minas Gerais (Brazil), and prepare specimens to determine the fresh (slump test, adhesiveness and porosity) and hardened (compression strength) of concrete. Were fabricated five concrete formulations, one reference (RC) and four with ceramic scrap substituted for coarse aggregate in the proportions of 25% (CSC-I), 50% (CSC-II), 75% (CSC-III) and 100% (CSC -IV). Fresh concretes, two formulations did not show adhesiveness (CSC-III and CSC-IV) and two a small water runoff (CSC-I and CSC-II), however, without compromising the concrete’s workability. Regarding the compression strength, the average values presented were very good, including the formulation with 100% ceramic scrap (fc = 47.78 MPa). Another important aspect observed in the rupture modes was the small adhesion between the ceramic scrap and the mortar due to the glazing in the contour of the waste. As for the porosity of the concretes, those with 25%, 75% and 100% of ceramic scrap in their composition presented lower values than the reference concrete.
DOI: 10.6084/m9.figshare.8260025.v1
title: Experimental study of dehydration processes of raspberries (Rubus Idaeus ) with microwave and solar drying

description: Abstract The aim of the present study was to evaluate the effect of solar and microwave drying on raspberries (Rubus Idaeus) cv. Heritage. The efficiency of drying was evaluated in terms of weight reduction in function of the time. The quality properties evaluated were color, texture, antioxidant capacity and total polyphenols content. The results showed that solar drying and microwave drying allowed a good preservation of surface color in the final product. However, the solar drying achieved a desirable texture in dried raspberries compared to microwave drying. Neither solar drying nor microwave drying allowed a high retention of the antioxidant capacity. Nevertheless, both processes allow obtaining final stable fruits (low water activity) at any time of the year.
DOI: 10.6084/m9.figshare.8260013
title: Production of low density wood-cement composites by vibro-dynamic compaction method

description: ABSTRACT The aim of this work was evaluate the potential use of timbers from four tropical Amazonian species for production of wood-cement composites by vibro-compaction densification method. Wood particles were made from slab wood of Murici (Byrsonima crispa), Red Inga (Inga paraensis), Inga (Inga alba) e Mata-Mata (Eschweilera odora). All species were considered suitable for composites production according to the CA Factor test. Composites physical (density, water absorption and thickness swelling) and mechanical (internal bond, static bending and compressive strength) properties were evaluated. Wood density and particle size influenced the composites final density and their water absorption and modulus of elasticity properties. The particle surface area also affected negatively the material's axial compressive strength. Method and wood showed potential for production of composites with possible application as filling materials in civil construction.
DOI: 10.6084/m9.figshare.8260016
title: Influence of the use of fly ash on the adiabatic heat evolution and compressive strength of concretes

description: ABSTRACT The construction of high buildings has required the execution of pile caps that reach thousands of m3 of concrete. In general, these structures are built using self-compacting and/or high compressive strength concretes, resulting in high binder contents. In these cases, the use of fly ash replacing Portland cement is a well-known alternative, both for the reduction of hydration heat and for the mitigation of delayed ettringite formation. However, the high binder contents generally used in such concretes results in high temperatures, creating an uncertainty about the efficacy of this mineral admixture for the reduction of the hydration heat. Thus, the current work aims to evaluate the effect of the replacement of Portland cement by fly ash in the adiabatic elevation of temperature and in the compressive strength of concretes. In this regard, concretes were produced with three classes of compressive strength (35, 45 and 55 MPa) and four cement replacement ratios by fly ash (0, 15, 30 and 45%). The temperature elevation of the concretes was monitored by an adiabatic calorimeter for 72 hours. At 28 days, the compressive strength of specimens cured in the adiabatic condition and at room temperature were determined. Finally, the pozzolanic activity of fly ash was evaluated by thermogravimetric analysis (TGA). It was found that, regardless of the resistance class or the replacement content of fly ash, the adiabatic elevation coefficients (corresponding to the temperature variation divided by the consumption of binder / m3 of concrete) were quite similar. The adiabatic condition promoted a reduction in compressive strength at 28 days, on the order of 10% compared to curing at room temperature. Also, the pozzolanic activity of fly ash was confirmed by TGA. Considering the results, it can be concluded that the use of fly ash in large masses of concrete with high binder contents becomes an inefficient alternative for the reduction of the heat release. However, its use is indicated because of the benefits in compressive strength and prevention of delayed ettringite formation.
DOI: 10.6084/m9.figshare.8260019.v1
title: Direct inhibitory effect of caffeine on viability, synthesis activity and gene expression in cultures of chondrocytes extracted from the articular cartilage of rats

description: ABSTRACT The aim of this study was to evaluate the effect of concentrations of caffeine on the viability, synthesis activity and gene expression in cultures of chondrocytes. Extracted articular cartilage from the femurs and tibias of 15 Wistar rats at three days old to isolate chondrocytes. Chondrocytes were cultured in chondrogenic medium (control) or supplemented with caffeine (0.5, 1.0, 2.0mM). Cell viability, alkaline phosphatase activity and collagen synthesis were assessed using colorimetric assays at 7, 14, 21 days. The chondrocyte cultures of all groups grown under coverslips were stained with hematoxylin-eosin to determine the percentage of cells/field and with PAS, safranin O, alcian blue to determine the percentage of matrix chondrogenic/field at 21 days. The expressions of gene transcripts for aggrecan, collagen-II, Sox-9, Runx-2 and alkaline phosphatase were also evaluated by RT-PCR at 21 days. The means were compared using Student-Newman-Keuls. Caffeine significantly reduced the conversion of MTT to formazan, percentage of cells/field, collagen synthesis, alkaline phosphatase activity, synthesis of PAS+, safranin O+ and alcian blue+ chondrogenic matrix, and the expression of aggrecan, Sox-9 and II collagen. It is concluded that caffeine at concentrations of 0.5, 1.0, 2.0mM has a direct inhibitory effect on chondrogenesis in cultures of chondrocytes from rats.
DOI: 10.6084/m9.figshare.8260016.v1
title: Influence of the use of fly ash on the adiabatic heat evolution and compressive strength of concretes

description: ABSTRACT The construction of high buildings has required the execution of pile caps that reach thousands of m3 of concrete. In general, these structures are built using self-compacting and/or high compressive strength concretes, resulting in high binder contents. In these cases, the use of fly ash replacing Portland cement is a well-known alternative, both for the reduction of hydration heat and for the mitigation of delayed ettringite formation. However, the high binder contents generally used in such concretes results in high temperatures, creating an uncertainty about the efficacy of this mineral admixture for the reduction of the hydration heat. Thus, the current work aims to evaluate the effect of the replacement of Portland cement by fly ash in the adiabatic elevation of temperature and in the compressive strength of concretes. In this regard, concretes were produced with three classes of compressive strength (35, 45 and 55 MPa) and four cement replacement ratios by fly ash (0, 15, 30 and 45%). The temperature elevation of the concretes was monitored by an adiabatic calorimeter for 72 hours. At 28 days, the compressive strength of specimens cured in the adiabatic condition and at room temperature were determined. Finally, the pozzolanic activity of fly ash was evaluated by thermogravimetric analysis (TGA). It was found that, regardless of the resistance class or the replacement content of fly ash, the adiabatic elevation coefficients (corresponding to the temperature variation divided by the consumption of binder / m3 of concrete) were quite similar. The adiabatic condition promoted a reduction in compressive strength at 28 days, on the order of 10% compared to curing at room temperature. Also, the pozzolanic activity of fly ash was confirmed by TGA. Considering the results, it can be concluded that the use of fly ash in large masses of concrete with high binder contents becomes an inefficient alternative for the reduction of the heat release. However, its use is indicated because of the benefits in compressive strength and prevention of delayed ettringite formation.
DOI: 10.6084/m9.figshare.8260004
title: Concretes with recycled aggregates of construction and demolition waste and mineral additions: a bibliographic analysis

description: ABSTRACT The environmental impact caused by the production of concrete must be reduced to make it a more sustainable material. The use of recycled aggregates in place of natural aggregates and mineral admixture in partial replacement to cement are alternatives that can make concrete a material with lower load of pollutants associated with your production. Using the methodology of ProKnow-C (Knowledge Development Process – Construtivist), was performed a selection and analysis of articles to assess the scene of recent research on concrete with recycled aggregate from construction waste and demolition (CDW) combined with different kinds of mineral admixture. Through the ProKnow-C methodology was obtained a bibliographic portfolio composed of eleven papers. The portfolio items were analyzed to assess which mineral additions and ratio that were used and your efficiency to improve mechanical performance and durability of the recycled aggregate concrete in total or partial replacement to the natural aggregate, both fine and coarse. Research has shown that recycled aggregates of CDW can be used at higher replacement ratio for natural aggregates when combined with the use of some kind of mineral admixture. Among the additions used in research evaluated are silica fume, fly ash and granulated blast furnace slag and each type of admixture used presents an ideal ratio to be used in partial replacement for the cement.
DOI: 10.6084/m9.figshare.8260007
title: Growth of local industrial employment in Brazil: does the degree of specialization by technological intensity matter?

description: ABSTRACT The aim of this paper is to revisit the debate on the degree of specialization and industrial diversification and the growth of local manufacturing employment in Brazil. A matrix of sectoral spillovers is built in which it is verified whether sectors, grouped by technological intensity, influence the performance of disaggregated manufacturing groups. Spatial data panel techniques are used to control non-observed local effects and possible spatial dependence over the period 1995-2014. The results show that specializations in low-technology manufacturing groups create stimulus for several other manufacturing groups regardless of the level of technological intensity. The spillovers coming from high technology manufacturing industries are less frequent, though they also occur depending on the industrial manufacturing group considered. In general, sectors of higher and lower technological intensity flourish with the presence of MAR externalities. We conclude that the diversification/specialization debate can vary considerably, requiring specific industrial and regional policies by manufacturing industries.
DOI: 10.6084/m9.figshare.8260013.v1
title: Production of low density wood-cement composites by vibro-dynamic compaction method

description: ABSTRACT The aim of this work was evaluate the potential use of timbers from four tropical Amazonian species for production of wood-cement composites by vibro-compaction densification method. Wood particles were made from slab wood of Murici (Byrsonima crispa), Red Inga (Inga paraensis), Inga (Inga alba) e Mata-Mata (Eschweilera odora). All species were considered suitable for composites production according to the CA Factor test. Composites physical (density, water absorption and thickness swelling) and mechanical (internal bond, static bending and compressive strength) properties were evaluated. Wood density and particle size influenced the composites final density and their water absorption and modulus of elasticity properties. The particle surface area also affected negatively the material's axial compressive strength. Method and wood showed potential for production of composites with possible application as filling materials in civil construction.
DOI: 10.6084/m9.figshare.8260007.v1
title: Growth of local industrial employment in Brazil: does the degree of specialization by technological intensity matter?

description: ABSTRACT The aim of this paper is to revisit the debate on the degree of specialization and industrial diversification and the growth of local manufacturing employment in Brazil. A matrix of sectoral spillovers is built in which it is verified whether sectors, grouped by technological intensity, influence the performance of disaggregated manufacturing groups. Spatial data panel techniques are used to control non-observed local effects and possible spatial dependence over the period 1995-2014. The results show that specializations in low-technology manufacturing groups create stimulus for several other manufacturing groups regardless of the level of technological intensity. The spillovers coming from high technology manufacturing industries are less frequent, though they also occur depending on the industrial manufacturing group considered. In general, sectors of higher and lower technological intensity flourish with the presence of MAR externalities. We conclude that the diversification/specialization debate can vary considerably, requiring specific industrial and regional policies by manufacturing industries.
DOI: 10.6084/m9.figshare.8260004.v1
title: Concretes with recycled aggregates of construction and demolition waste and mineral additions: a bibliographic analysis

description: ABSTRACT The environmental impact caused by the production of concrete must be reduced to make it a more sustainable material. The use of recycled aggregates in place of natural aggregates and mineral admixture in partial replacement to cement are alternatives that can make concrete a material with lower load of pollutants associated with your production. Using the methodology of ProKnow-C (Knowledge Development Process – Construtivist), was performed a selection and analysis of articles to assess the scene of recent research on concrete with recycled aggregate from construction waste and demolition (CDW) combined with different kinds of mineral admixture. Through the ProKnow-C methodology was obtained a bibliographic portfolio composed of eleven papers. The portfolio items were analyzed to assess which mineral additions and ratio that were used and your efficiency to improve mechanical performance and durability of the recycled aggregate concrete in total or partial replacement to the natural aggregate, both fine and coarse. Research has shown that recycled aggregates of CDW can be used at higher replacement ratio for natural aggregates when combined with the use of some kind of mineral admixture. Among the additions used in research evaluated are silica fume, fly ash and granulated blast furnace slag and each type of admixture used presents an ideal ratio to be used in partial replacement for the cement.
DOI: 10.6084/m9.figshare.8259992
title: Bivariate Copula-based Linear Mixed-effects Models: An Application to Longitudinal Child Growth Data

description: ABSTRACT Multiple longitudinal outcomes are common in public health research and adequate methods are required when there is interest in the joint evolution of response variables over time. However, the main drawback of joint modeling procedures is the requirement to specify the joint density of all outcomes and their correlation structure, as well as numerical difficulties in statistical inference, when the dimension of these outcomes increases. To overcome such difficulty, we present two procedures to deal with multivariate longitudinal data. We first present an univariate approach, for which linear mixed-effects models are considered for each response variable separately. Then, a novel copula-based modeling is presented, in order to characterize relationships among the response variables. Both methodologies are applied to a real Brazilian data set on child growth.