A5028555308- Carbon Nanotubes in Composites
- Magnetic Properties and Synthesis of Ferrites
- Graphene research and applications
- Polymer Nanocomposites and Properties
- Ferroelectric and Piezoelectric Materials
- COVID-19 diagnosis using AI
- Magnetic properties of thin films
- Magneto-Optical Properties and Applications
- Magnetic and transport properties of perovskites and related materials
- Optical Coatings and Gratings
- Electromagnetic wave absorption materials
- Multiferroics and related materials
- Membrane Separation Technologies
- Electronic and Structural Properties of Oxides
- Surface Modification and Superhydrophobicity
- Iron oxide chemistry and applications
- Agricultural and Food Sciences
- COVID-19 Clinical Research Studies
- Fiber-reinforced polymer composites
- Silicone and Siloxane Chemistry
- TiO2 Photocatalysis and Solar Cells
- Nanopore and Nanochannel Transport Studies
- Polymer composites and self-healing
- Tribology and Wear Analysis
- Advanced ceramic materials synthesis
Universidade Federal de Minas Gerais
2006-2019
Centro Universitário de Belo Horizonte
2011
The influence of chemical modification by acid treatment followed triethylenetetramine (TETA) functionalization on the surface multi-walled carbon nanotubes (MWCNT) was evaluated, both qualitative and quantitatively. Thermogravimetric analysis (TGA) showed that, in case amine-functionalized nanotubes, 29% mass loss can be attributed to -C(=O)TETA residual oxygen-containing functional groups. X-ray photoelectron spectroscopy (XPS) used observe oxygenated aminated functions covalently linked...
Composites based on epoxy/graphene were investigated for thermal-mechanical performance. Initially, few-layer graphene oxide (GO) was modified with tetraethylenepentamine (GO-TEPA) in a reaction assisted by microwave radiation. GO and GO-TEPA samples characterized their structure morphology. containing 0.1, 0.3 0.5 wt.% of prepared, the effect fillers morphology cryofractured regions epoxy matrix observed through electron microscopy images. Dynamic mechanical thermal analysis (DMA) tests...
ABSTRACT In this study, composites based on a thermoset polyurethane elastomer (PU) and multiwalled carbon nanotubes (MWCNT) in the case of PU high elastic modulus (>200 MPa) are analyzed for first time. As‐grown modified with 4 wt % oxygenated functions (MWCNT‐ox) were employed to compare their effect composite properties maxima mechanical (elastic tensile strength) reached at 0.5 MWCNT‐ox. Furthermore, by examining morphology using optical electron microscopies better dispersion...
ABSTRACT A microwave‐assisted functionalization of carbon nanotubes (CNTs) with isocyanate groups allowed a reduction time from 24 h to 30 min no change in the degree or nanotube characteristics. Polymer nanocomposites enhanced mechanical properties were obtained because tailored interface by covalent linkage between surface‐modified multiwalled‐carbon (MWCNTs) and an elastomeric polyurethane (PUE) matrix. The data revealed that composite containing 0.25 wt % MWCNT‐NCO showed increase 31%...
The influence of hydrogen utilized during the thermal treatment copper substrates on subsequent graphene growth is investigated. It known that various parameters such as nature carbon precursor, temperature and pressure strongly affect quality grown by chemical vapor deposition. Another important parameter partial adjusted stage in pre-growth annealing substrate. In attempts to elucidate role assisted substrate morphology growth, we subjected Cu foils under H2 atmosphere at different...
The use of nanofluids for industrial applications depends on its stability during transport and use. In this work, we demonstrate that graphene oxide (GO)-based aqueous can remaining stable as many 90 days. structural morphological analyses showed the GO samples have an average thickness two graphitic layers with interlayer spacing 1 nm. long-term colloidal was monitored days using three different techniques: UV-vis, zeta potential (ζ) DLS, which confirmed stability. observed ζ value...
OBJECTIVE: Defining priority vaccination groups is a critical factor to reduce mortality rates. METHODS: We sought identify population for covid-19 vaccination, based on in-hospital risk of death, by using Extreme Gradient Boosting Machine Learning (ML) algorithm. performed retrospective cohort study comprising 49,197 patients (18 years or older), with RT-PCR-confirmed covid-19, who were hospitalized in any the 336 Brazilian hospitals considered this study, from March 19th, 2020, 22nd, 2021....
OBJETIVO: Esta pesquisa tem como objetivo estudar as propriedades do autolisado de levedura (Saccharomyces cerevisiae) proveniente cachaça alambique, investigando a composição centesimal, o perfil acídico e análise microbiológica material, bem realizar sensorial pão queijo adicionado com desidratado. MÉTODOS: O foi obtido pela lavagem autólise da biomassa. A secagem realizada em secador bandeja na temperatura 70ºC. Realizaram-se seguintes análises: caracterização físico-química (teor...
Cobalt ferrite composite thin films, CoFe2O4/SiO2, were prepared by sol-gel process, using tetraethylorthosilicate (TEOS) as a precursor for silica, and metallic nitrates precursors ferrite. The obtained dip-coated films thermally treated at 550, 750, 950 ºC transparent, homogeneous adherent. Their magnetic properties measured from 2.5 K to 300 SQUID magnetometer. Superparamagnetic behaviour was observed room temperature below blocking appears with coercivity values increasing annealing temperature.
OBJECTIVE: To develop and validate a predictive model utilizing machine-learning techniques for estimating the length of hospital stay among patients who underwent coronary artery bypass grafting.METHODS: Three machine learning models (random forest, extreme gradient boosting neural networks) three traditional regression (Poisson regression, linear negative binomial regression) were trained in dataset 9,584 grafting between January 2017 December 2021. The data collected from discharges 133...
In order to study the influence of insulator layer thickness in heterojunctions, (YBa2Cu3O7-δ[20nm]/ PrBa2Cu3Oy/La1/3Ca2/3MnO3[20nm])x20 superlattices were prepared by pulsed laser deposition using three PrBa2Cu3Oy thicknesses and two different sequences deposition. Sample characterization showed primitive orthorhombic crystalline arrangement for YBCO LCMO, however, a slightly disordered structure was observed sample having thicker PBCO layer. Microscopy analyses indicated both parameters...
Nanostructure oxide thin films have potential technological use due to their unique properties, diverse from those of similar polycrystalline materials. The an inorganic matrix as a nanocrystalline particle host allows uniform size, and homogeneous distribution dispersion. Nickel cobalt ferrite composite using silica were prepared by sol-gel process tetraethylorthosilicate (TEOS) precursor silica, metallic nitrates precursors ferrite. deposited on various substrates the dip- coating process....
Background: Defining priority vaccination groups is a critical factor to reduce mortality rates.Methods: We aimed identify priority-population for COVID-19 vaccination, based on in-hospital risk of death by using Extreme Gradient Boosting Machine Learning (ML) algorithm. performed retrospective cohort study comprising 49,197 patients (18 years or older) with quantitative RT-PCR-confirmed COVID-19, who were hospitalized in one the 336 Brazilian hospitals from March 19th, 2020 22nd, 2021....