cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.20010063
title: Direct-write assembly of 3D scaffolds using colloidal calcium phosphates inks

description: Additive manufacture techniques using concentrated colloidal inks are a promising approach for creating three-dimensional (3D) calcium phosphates scaffolds for bone repair and regeneration. Among those, the direct-write assembly allows building scaffolds with precise size and geometry. In the present work, commercial β-TCP and HA were used to produce two types of colloidal ink. According to the ink composition used to build the scaffolds, two different groups were obtained. Group I: scaffolds produced with β-TCP-based ink; and Group II: scaffolds produced with biphasic CaP-based ink (BCP). The 3D scaffolds were assembled in a cylindrical shape (Φ = 8mm x H= 16 mm) with interconnected pore channels of approximately 500μm by robotic deposition of 64 layers using a robocasting machine. The mechanical compression property of the scaffolds was determined using universal testing machine. To assure the controlled geometry of the scaffolds, digital images were obtained by reconstructing each individual scan obtained with a micro-computed tomography. An optical contact angle measurement system was used to evaluate the wettability of the materials. After analyzing the results it was concluded that: the robocasting system is suitable for building 3D periodic calcium phosphates scaffolds; the direct-write assembly didn't change the hydrophilic characteristic of CaPs; and presented mean compressive strength around 11 MPa (β-TCP group) and 15 MPa (BCP group), which is compatible with trabecular bone.
DOI: 10.6084/m9.figshare.20010063.v1
title: Direct-write assembly of 3D scaffolds using colloidal calcium phosphates inks

description: Additive manufacture techniques using concentrated colloidal inks are a promising approach for creating three-dimensional (3D) calcium phosphates scaffolds for bone repair and regeneration. Among those, the direct-write assembly allows building scaffolds with precise size and geometry. In the present work, commercial β-TCP and HA were used to produce two types of colloidal ink. According to the ink composition used to build the scaffolds, two different groups were obtained. Group I: scaffolds produced with β-TCP-based ink; and Group II: scaffolds produced with biphasic CaP-based ink (BCP). The 3D scaffolds were assembled in a cylindrical shape (Φ = 8mm x H= 16 mm) with interconnected pore channels of approximately 500μm by robotic deposition of 64 layers using a robocasting machine. The mechanical compression property of the scaffolds was determined using universal testing machine. To assure the controlled geometry of the scaffolds, digital images were obtained by reconstructing each individual scan obtained with a micro-computed tomography. An optical contact angle measurement system was used to evaluate the wettability of the materials. After analyzing the results it was concluded that: the robocasting system is suitable for building 3D periodic calcium phosphates scaffolds; the direct-write assembly didn't change the hydrophilic characteristic of CaPs; and presented mean compressive strength around 11 MPa (β-TCP group) and 15 MPa (BCP group), which is compatible with trabecular bone.
DOI: 10.6084/m9.figshare.20010067
title: When nanotechnology meets filteration: From nanofiber fabrication to biomimetic design

description: Nanotechnology for the scientific and economical revival is of indispensable importance, and the so-called nano-age or nano-industrialization is coming. The paper reveals the very frontier of nanotechnology in mass-production of nanofibers, and the bubble-electrospinning is introduced, and its application to filteration is emphasized. By mimicking the structure of silkworm cocoon, the filteration efficiency reaches its maximum, while the pressure drop through the filter is minimal, and small water cluster is obtained after nanofiber membrane for water purification.
DOI: 10.6084/m9.figshare.20010067.v1
title: When nanotechnology meets filteration: From nanofiber fabrication to biomimetic design

description: Nanotechnology for the scientific and economical revival is of indispensable importance, and the so-called nano-age or nano-industrialization is coming. The paper reveals the very frontier of nanotechnology in mass-production of nanofibers, and the bubble-electrospinning is introduced, and its application to filteration is emphasized. By mimicking the structure of silkworm cocoon, the filteration efficiency reaches its maximum, while the pressure drop through the filter is minimal, and small water cluster is obtained after nanofiber membrane for water purification.
DOI: 10.6084/m9.figshare.20010073
title: Portland cement composites with carbon nanotubes (CNT) addition: Properties in freshly state and compressive strength

description: Currently there are some studies on the addition of carbon nanotubes (CNTs) in cement composites. These studies indicate enhancements in the mechanical properties, such as increase in compressive strength, tensile strength and durability, and porosity decrease. Based on these possible improvements, this research was conducted to analyze the influence of CNTs on the compressive strength of mortar for rehabilitation of concrete structures, as well as in their consistency. Compressive strength, squeeze flow, flow table, marsh funnel and mini-slump tests were carried. A control mortar and paste were used (without carbon nanotubes added), which was replicated with the same mix proportioning and the incorporation of 5 levels of CNTs related to the cement mass: 0.1%, 0.2%, 0.3%, 0.4% to 0.5%. These concentrations were chosen to cover the commonly range used in researches about Portland cement composites with CNTs addition. Regarding the tests for measuring the fluidity of mortars and pastes, it was found that the higher the percentage of CNT, more consistent the cement Portland composite became, with evidence that smaller or equal to 0.3% levels of NTCs are more adequate to maintain the fluidity of the Portland cement composite. Results indicate that the addition of 0.40% of carbon nanotubes increases the compressive strength by 27%. On the other hand, addition of 0.5% of CNT became the Portland cement composite very consistent, making difficult the molding process, so that the increase in compressive strength was zero compared to the control mortar.
DOI: 10.6084/m9.figshare.20010073.v1
title: Portland cement composites with carbon nanotubes (CNT) addition: Properties in freshly state and compressive strength

description: Currently there are some studies on the addition of carbon nanotubes (CNTs) in cement composites. These studies indicate enhancements in the mechanical properties, such as increase in compressive strength, tensile strength and durability, and porosity decrease. Based on these possible improvements, this research was conducted to analyze the influence of CNTs on the compressive strength of mortar for rehabilitation of concrete structures, as well as in their consistency. Compressive strength, squeeze flow, flow table, marsh funnel and mini-slump tests were carried. A control mortar and paste were used (without carbon nanotubes added), which was replicated with the same mix proportioning and the incorporation of 5 levels of CNTs related to the cement mass: 0.1%, 0.2%, 0.3%, 0.4% to 0.5%. These concentrations were chosen to cover the commonly range used in researches about Portland cement composites with CNTs addition. Regarding the tests for measuring the fluidity of mortars and pastes, it was found that the higher the percentage of CNT, more consistent the cement Portland composite became, with evidence that smaller or equal to 0.3% levels of NTCs are more adequate to maintain the fluidity of the Portland cement composite. Results indicate that the addition of 0.40% of carbon nanotubes increases the compressive strength by 27%. On the other hand, addition of 0.5% of CNT became the Portland cement composite very consistent, making difficult the molding process, so that the increase in compressive strength was zero compared to the control mortar.
DOI: 10.6084/m9.figshare.20010082
title: Otimização reológica de suspensões aquosas de óxido de ferro (III)

description: In this work the dispersion of iron oxide III particles in aqueous media was studied. To achieve the maximum solid content zeta potential measurements were carried as a function of pH. The influences of two different types of polyacrylates as dispersants were investigated. Suspensions were produced by varying solids concentration up to 30 vol.%. The results showed a strong influence of pH on the size distribution of the particles in suspension. The most efficient dispersant towards particle dispersion was sodium polyacrylate. The maximum solid content in the suspension was optimized to 25 vol % with density values higher than 35% theoretical density with 2 wt.% polyacrylate.
DOI: 10.6084/m9.figshare.20010082.v1
title: Otimização reológica de suspensões aquosas de óxido de ferro (III)

description: In this work the dispersion of iron oxide III particles in aqueous media was studied. To achieve the maximum solid content zeta potential measurements were carried as a function of pH. The influences of two different types of polyacrylates as dispersants were investigated. Suspensions were produced by varying solids concentration up to 30 vol.%. The results showed a strong influence of pH on the size distribution of the particles in suspension. The most efficient dispersant towards particle dispersion was sodium polyacrylate. The maximum solid content in the suspension was optimized to 25 vol % with density values higher than 35% theoretical density with 2 wt.% polyacrylate.
DOI: 10.6084/m9.figshare.20010087
title: Molecular dynamic study of the jet noise about the micro-scale tube

description: This paper studies the two-dimensional micro-scale molecular simulations of the jet flow using Lagrange discrete systems and adopting Andresen flexible constraint mechanism. At the effects of different excitation conditions and boundary conditions, the low Mach number flow field and sound field are obtained, and characteristic results are given. At the jet flow and pipe flow regions, particles velocities distribution is consistent with traditional method. There are many small groups which have a bigger velocity value, and form the disturbance sources. The stronger interaction with the tube wall produces greater sound pressure, thus random collisions method at the tube wall is effective to deal with sound propagation problem. Therefore, this paper offers preliminary and calculated basis for the molecular and macroscopic quantum aerodynamic problems.
DOI: 10.6084/m9.figshare.20010087.v1
title: Molecular dynamic study of the jet noise about the micro-scale tube

description: This paper studies the two-dimensional micro-scale molecular simulations of the jet flow using Lagrange discrete systems and adopting Andresen flexible constraint mechanism. At the effects of different excitation conditions and boundary conditions, the low Mach number flow field and sound field are obtained, and characteristic results are given. At the jet flow and pipe flow regions, particles velocities distribution is consistent with traditional method. There are many small groups which have a bigger velocity value, and form the disturbance sources. The stronger interaction with the tube wall produces greater sound pressure, thus random collisions method at the tube wall is effective to deal with sound propagation problem. Therefore, this paper offers preliminary and calculated basis for the molecular and macroscopic quantum aerodynamic problems.
DOI: 10.6084/m9.figshare.20010090.v1
title: Tartrazine degradation by supported TiO2on magnetic particles

description: ABSTRACTMagnetic beads were obtained by dropping a solution of sodium alginate containing magnetite particles into a CaCl2 solution. TiO2anatase particles were synthetized by a sol-gel method at low temperature (75 °C), and were supported on magnetic beads to obtain the magnetic photocatalyst, MC. Magnetite particles and magnetic photocatalyst were characterized by nitrogen adsorption (BET, surface area), their morphology observed by scanning electronic microscopy (SEM) and TiO2 phase was analyzed by means of Raman spectroscopy. The photocatalytic activity of MC was evaluated on tartrazine degradation, highly used in food industry, at two different concentrations. Finally, MC stability was evaluated by reusability assays in several subsequent cycles. Results showed a good photocatalytic response for tartrazine degradation, especially at low concentration, easy recuperation and appropriate perform in the reusability of MC.
DOI: 10.6084/m9.figshare.20010090
title: Tartrazine degradation by supported TiO2on magnetic particles

description: ABSTRACTMagnetic beads were obtained by dropping a solution of sodium alginate containing magnetite particles into a CaCl2 solution. TiO2anatase particles were synthetized by a sol-gel method at low temperature (75 °C), and were supported on magnetic beads to obtain the magnetic photocatalyst, MC. Magnetite particles and magnetic photocatalyst were characterized by nitrogen adsorption (BET, surface area), their morphology observed by scanning electronic microscopy (SEM) and TiO2 phase was analyzed by means of Raman spectroscopy. The photocatalytic activity of MC was evaluated on tartrazine degradation, highly used in food industry, at two different concentrations. Finally, MC stability was evaluated by reusability assays in several subsequent cycles. Results showed a good photocatalytic response for tartrazine degradation, especially at low concentration, easy recuperation and appropriate perform in the reusability of MC.
DOI: 10.6084/m9.figshare.20010093
title: Optical characterization of surface defects incadmium selenide (CdSe) colloidal quantum dots

description: ABSTRACTIn this work, non-stoichiometric defects and dangling bond defects were optically characterized for CdSe colloidal quantum dots (QDs), which were prepared by the thermal decomposition method. Particularly, the presence of defects linked to a high QD surface to volume ratio was studied. The photoluminescence (PL) spectra of the samples show two bands, which could be associated to excitonic recombination and excitonic recombination via surface defects. The samples remained untreated for a period of time after preparation. During this time a gradual deterioration of the QDs was observed by monitoring the evolution of PL spectra. An increase in intensity of the band associated to recombination via defects, with respect to the excitonic emission band, was observed. Subsequently, the samples were washed using abundant ethanol and dissolved in 1-octadecene. After this treatment a gradual recovery of the excitonic PL band was observed. This could be attributed to the removal of reaction residues that could give rise to defects, and to a rearrangement of the surfactants, thus showing a form of surface defects passivation. For all the samples, investigated in this work, a greater presence of surface defects for QDs of higher surface to volume ratio was observed.
DOI: 10.6084/m9.figshare.20010093.v1
title: Optical characterization of surface defects incadmium selenide (CdSe) colloidal quantum dots

description: ABSTRACTIn this work, non-stoichiometric defects and dangling bond defects were optically characterized for CdSe colloidal quantum dots (QDs), which were prepared by the thermal decomposition method. Particularly, the presence of defects linked to a high QD surface to volume ratio was studied. The photoluminescence (PL) spectra of the samples show two bands, which could be associated to excitonic recombination and excitonic recombination via surface defects. The samples remained untreated for a period of time after preparation. During this time a gradual deterioration of the QDs was observed by monitoring the evolution of PL spectra. An increase in intensity of the band associated to recombination via defects, with respect to the excitonic emission band, was observed. Subsequently, the samples were washed using abundant ethanol and dissolved in 1-octadecene. After this treatment a gradual recovery of the excitonic PL band was observed. This could be attributed to the removal of reaction residues that could give rise to defects, and to a rearrangement of the surfactants, thus showing a form of surface defects passivation. For all the samples, investigated in this work, a greater presence of surface defects for QDs of higher surface to volume ratio was observed.
DOI: 10.6084/m9.figshare.20010091
title: Complex modulus of asphalt mix with calcined clay under four-point bending

description: In mechanistic analysis, the complex modulus is a fundamental parameter for the constitutive models of asphalt concrete. The four-point bending test, widely used in Europe, is among the most modern options for obtaining the complex modulus. In this study a four-point bending tests is carried out to obtain the dynamic modulus and phase angle of the asphalt concrete, employing Amazon representative conditions for the coarse aggregate and temperature on the road surface, which reaches almost 60 °C for many hours a day. As aggregate, taking into account the regional shortage of stone materials, we used the ASAC - Synthesized Calcined Clay Aggregate, a promising material due the abundance of raw materials and the technical and financial feasibility. As a result of the tests, it has been found the dynamic modulus and the phase angle at different frequencies and temperatures. Considering the local conditions of temperature and traffic, the dynamic module presented abrupt change, showing a drop of up to 93.3 % in value, with the surface appearing very susceptible to permanent deformation, recurring problem in local asphalt pavements.
DOI: 10.6084/m9.figshare.20010091.v1
title: Complex modulus of asphalt mix with calcined clay under four-point bending

description: In mechanistic analysis, the complex modulus is a fundamental parameter for the constitutive models of asphalt concrete. The four-point bending test, widely used in Europe, is among the most modern options for obtaining the complex modulus. In this study a four-point bending tests is carried out to obtain the dynamic modulus and phase angle of the asphalt concrete, employing Amazon representative conditions for the coarse aggregate and temperature on the road surface, which reaches almost 60 °C for many hours a day. As aggregate, taking into account the regional shortage of stone materials, we used the ASAC - Synthesized Calcined Clay Aggregate, a promising material due the abundance of raw materials and the technical and financial feasibility. As a result of the tests, it has been found the dynamic modulus and the phase angle at different frequencies and temperatures. Considering the local conditions of temperature and traffic, the dynamic module presented abrupt change, showing a drop of up to 93.3 % in value, with the surface appearing very susceptible to permanent deformation, recurring problem in local asphalt pavements.
DOI: 10.6084/m9.figshare.20010096
title: Production of copper-based metallic glasses: evolution of the phases during mechanical alloying

description: ABSTRACTIn this study, different, copper-based materials were fabricated under equal milling conditions (SPEX 8000D, argon atmosphere, stearic acid, BPR=10:1) and variable amounts of time, from 1 to 120 hours, in order to compare the microstructural changes during the process. The materials were: Pure copper; Cu-Ni alloys; Cu-Zr alloys; and Cu-Ni-Zr alloys. Subsequent to milling, the samples were measured with X-Ray Diffraction, Electron Transmission Microscopy, and Differential Scanning Calorimetry. According to the results, copper, upon being subjected to the process, reaches a crystallite size that tends towards an asymptote starting at 5 hours. In the Cu-Ni system, instead of observing a microstructural refinement during this same period, there was rather a total solubilization of the nickel into the copper (40-60 and50-50), and of the copper into the nickel (60-40). As for the Cu-Zr binary system, it was found that, for five hours as well, the system was practically amorphous (60-40 and 50-50), a condition also present in the Cu-Ni-Zr ternary alloys (60-10-30 and 50-10-40).
DOI: 10.6084/m9.figshare.20010097
title: Evolution of texture and microstructure during thermo-mechanical processingin ultrathin low carbon steels

description: ABSTRACT In this research paper an analysis concerning the evolution of crystallographic texture during hot rolling processing of low carbon steel is presented. The study was performed on a steel sheet with an initial thickness of 1.9 mm used in the process of cold rolling. In order to assess the differences between tensile and compressive deformation, a 90˚ cold bending was carried out in this specimen. Texture evolution analysis greatly helps to assess the effect of some mechanical properties, particularly formability. The material was annealed under different conditions of time and temperature using an inert atmosphere. The chemical composition was determined by optical emission spectrometry. The study of crystallographic texture present in this steel was performed using the electron backscatter diffraction (EBSD) technique by means of OIM (Orientation Imaging Microscopy) mapping, inverse pole figures and orientation distribution functions (ODFs). Electron diffraction Backscattered (EBSD) is a technique that allows to detect and analyze information crystallographic on the surface of a sample which is observed by scanning electron microscope (SEM). An analysis of the effect of processing parameters and differences between tensile and compressive deformation on the microstructure and crystallographic texture changes in these materials is presented. The results are discussed in terms of both the resulting anisotropy after the annealing treatment and the primary fibers founded by this technique.
DOI: 10.6084/m9.figshare.20010097.v1
title: Evolution of texture and microstructure during thermo-mechanical processingin ultrathin low carbon steels

description: ABSTRACT In this research paper an analysis concerning the evolution of crystallographic texture during hot rolling processing of low carbon steel is presented. The study was performed on a steel sheet with an initial thickness of 1.9 mm used in the process of cold rolling. In order to assess the differences between tensile and compressive deformation, a 90˚ cold bending was carried out in this specimen. Texture evolution analysis greatly helps to assess the effect of some mechanical properties, particularly formability. The material was annealed under different conditions of time and temperature using an inert atmosphere. The chemical composition was determined by optical emission spectrometry. The study of crystallographic texture present in this steel was performed using the electron backscatter diffraction (EBSD) technique by means of OIM (Orientation Imaging Microscopy) mapping, inverse pole figures and orientation distribution functions (ODFs). Electron diffraction Backscattered (EBSD) is a technique that allows to detect and analyze information crystallographic on the surface of a sample which is observed by scanning electron microscope (SEM). An analysis of the effect of processing parameters and differences between tensile and compressive deformation on the microstructure and crystallographic texture changes in these materials is presented. The results are discussed in terms of both the resulting anisotropy after the annealing treatment and the primary fibers founded by this technique.