DSpace Coleção:http://www.repositorio.ufop.br/jspui/handle/123456789/5832024-01-27T06:17:56Z2024-01-27T06:17:56ZDelayed fluorescence by triplet−triplet annihilation from columnar liquid crystal films.Franca, Larissa GomesSantos, Paloma Lays dosPander, PiotrCabral, Marília Gabriela BelarminoCristiano, RodrigoCazati, ThiagoMonkman, Andrew P.Bock, HaraldEccher, Julianahttp://www.repositorio.ufop.br/jspui/handle/123456789/172622023-08-18T19:15:02Z2022-01-01T00:00:00ZTítulo: Delayed fluorescence by triplet−triplet annihilation from columnar liquid crystal films.
Autor(es): Franca, Larissa Gomes; Santos, Paloma Lays dos; Pander, Piotr; Cabral, Marília Gabriela Belarmino; Cristiano, Rodrigo; Cazati, Thiago; Monkman, Andrew P.; Bock, Harald; Eccher, Juliana
Resumo: Delayed fluorescence (DF) by triplet−triplet annihila-
tion (TTA) is observed in solutions of a benzoperylene-imidoester
mesogen that shows a hexagonal columnar mesophase at room
temperature in the neat state. A similar benzoperylene-imide with a
slightly smaller HOMO−LUMO gap, that also is hexagonal columnar
liquid crystalline at room temperature, does not show DF in solution,
and mixtures of the two mesogens show no DF in solution either,
because of collisional quenching of the excited triplet states on the
imidoester by the imide. In contrast, DF by TTA from the imide but
not from the imidoester is observed in condensed films of such
mixtures, even though neat films of either single material are not
displaying DF. In contrast to the DF from the monomeric imidoester
in solution, DF of the imide occurs from dimeric aggregates in the
blend films, assisted by the imidoester. Thus, the close contact of intimately stacked molecules of the two different species in the
columnar mesophase leads to a unique mesophase-assisted aggregate DF. This constitutes the first observation of DF by TTA from
the columnar liquid crystalline state. If the imide is dispersed in films of polybromostyrene, which provides an external heavy-atom
effect facilitating triplet formation, DF is also observed. Organic light-emitting diodes (OLEDs) devices incorporating these liquid
crystal molecules demonstrated high external quantum efficiency (EQE). On the basis of the literature and to the best of our
knowledge, the EQE reported is the highest among nondoped solution-processed OLED devices using a columnar liquid crystal
molecule as the emitting layer.2022-01-01T00:00:00ZWater diffusion in carbon nanotubes for rigid and flexible models.Mendonça, Bruno Henrique da Silva eMoraes, Elizane Efigenia deBatista, Ronaldo Junio CamposOliveira, Alan Barros deBarbosa, Márcia Cristina BernardesChacham, Heliohttp://www.repositorio.ufop.br/jspui/handle/123456789/172612023-08-18T19:08:52Z2023-01-01T00:00:00ZTítulo: Water diffusion in carbon nanotubes for rigid and flexible models.
Autor(es): Mendonça, Bruno Henrique da Silva e; Moraes, Elizane Efigenia de; Batista, Ronaldo Junio Campos; Oliveira, Alan Barros de; Barbosa, Márcia Cristina Bernardes; Chacham, Helio
Resumo: We compared the diffusion of water confined in
armchair and zigzag carbon nanotubes for rigid and flexible water
models. Using one rigid model, TIP4P/2005, and two flexible
models, SPC/Fw and SPC/FH, we found that the number of the
hydrogen bonds that water forms depends on the structure of the
nanotube, directly affecting the diffusion of water. The simulation
results reveal that, due to the hydrophobic nature of carbon
nanotubes and the degrees of freedom imposed by the water force
fields, water molecules tend to avoid the surface of the carbon
nanotube. This junction of variables plays a central role in the
diffusion of water, mainly in narrow and/or deformed nanotubes,
governing the mobility of confined water in a nontrivial way, where
the greater the degree of freedom of the water force field, the
smaller mobility it will have in confinement as we limit the competition between area and volume and it no longer plays the unique
role in changing water diffusivity.2023-01-01T00:00:00ZCharacterization of magnetic tailings from phosphate-ore processing in Alto Paranaíba.Silva, Fernando Brandão Rodrigues daAraújo, Fernando Gabriel da SilvaKrüger, Fernando Leopoldo vonSilva, Guilherme Jorge BrigoliniBatista, Ronaldo Junio CamposManhabosco, Taíse Mattehttp://www.repositorio.ufop.br/jspui/handle/123456789/172602023-08-18T19:04:50Z2022-01-01T00:00:00ZTítulo: Characterization of magnetic tailings from phosphate-ore processing in Alto Paranaíba.
Autor(es): Silva, Fernando Brandão Rodrigues da; Araújo, Fernando Gabriel da Silva; Krüger, Fernando Leopoldo von; Silva, Guilherme Jorge Brigolini; Batista, Ronaldo Junio Campos; Manhabosco, Taíse Matte
Resumo: The characterization studies of tailings from mining are crucial for the development of its reuse
processes and the reduction of impacts caused by its conditioning on the earth’s surface. This study
characterizes the magnetic tailings from phosphate-rock processing using X-ray diffraction, X-ray
fluorescence spectrometry and quantitative electron microscopy techniques. Samples were obtained
from the magnetic tailings deposit of a mining company in the Alto Paranaíba region, Minas Gerais.
The tailings are mainly composed of hematite/magnetite (74.92%), ilmenite (8.91%), fluorapatite
(8.8%), anatase (3.07%), calcite (1.67%), goethite (1.62%), and quartz (1.02%). The particle size of the
tailings is smaller than that specified for the production of sinter feed. The hematite/magnetite phase
is strongly associated with ilmenite and fluorapatite. New stages of comminution and separation are
needed due to the low degree of liberation of these minerals for a possible reuse of the components.2022-01-01T00:00:00ZColorimetric nanosensor for the determination of glyphosate herbicide in aqueous solutions.Silva, Cinthia Rocha daNeri, Lara Chrystina MaltaCarvalho, Thaís Adriany de SouzaBianchi, Jhonatan Rafael de OliveiraBianchi, Rodrigo FernandoSantos, Igor José Boggionehttp://www.repositorio.ufop.br/jspui/handle/123456789/172592023-08-18T19:02:13Z2023-01-01T00:00:00ZTítulo: Colorimetric nanosensor for the determination of glyphosate herbicide in aqueous solutions.
Autor(es): Silva, Cinthia Rocha da; Neri, Lara Chrystina Malta; Carvalho, Thaís Adriany de Souza; Bianchi, Jhonatan Rafael de Oliveira; Bianchi, Rodrigo Fernando; Santos, Igor José Boggione
Resumo: Detection of pesticides depends on complex, time-consuming, and costly techniques
performed only in some regions of Brazil. Thus, this study aimed to develop a sensitive, portable, easy-
to-handle, and fast nanosensor to determine the presence of glyphosate in aqueous solutions. The
Co(OH)2 nanostructure was synthesized, and the kinetic study of the interaction with pesticide
glyphosate-based was performed. The Co(OH)2 nanostructures had a fast and effective interaction,
confirmed by UV-Visible spectroscopy. Through experimental planning, the process for obtaining
nanostructures has been optimized, and the nanostructures obtained were in a size range of 434.2 nm
with a hexagonal nanoplate structure. The lower limit of color-based glyphosate detection was 0.178
g
.L
-1
. It was possible to identify the herbicide in the water of the tomato and sugar cane rinse by the
change of the watercolor into pink. Although the samples showed low absorbance, the color change was
noticeable to the naked eye. Therefore, to synthesize a structure that allows identifying glyphosate in a
colorimetric way.2023-01-01T00:00:00Z