Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Caetano R. Miranda is active.

Publication


Featured researches published by Caetano R. Miranda.


Journal of Chemical Theory and Computation | 2018

Multilevel Molecular Modeling Approach for a Rational Design of Ionic Current Sensors for Nanofluidics

Alexsandro Kirch; James Moraes de Almeida; Caetano R. Miranda

The complexity displayed by nanofluidic-based systems involves electronic and dynamic aspects occurring across different size and time scales. To properly model such kind of system, we introduced a top-down multilevel approach, combining molecular dynamics simulations (MD) with first-principles electronic transport calculations. The potential of this technique was demonstrated by investigating how the water and ionic flow through a (6,6) carbon nanotube (CNT) influences its electronic transport properties. We showed that the confinement on the CNT favors the partially hydrated Na, Cl, and Li ions to exchange charge with the nanotube. This leads to a change in the electronic transmittance, allowing for the distinguishing of cations from anions. Such an ionic trace may handle an indirect measurement of the ionic current that is recorded as a sensing output. With this case study, we are able to show the potential of this top-down multilevel approach, to be applied on the design of novel nanofluidic devices.


Proceedings of the National Academy of Sciences of the United States of America | 2017

Multiple pathways in pressure-induced phase transition of coesite

Wei Liu; Xuebang Wu; Yunfeng Liang; Changsong Liu; Caetano R. Miranda; Sandro Scandolo

Significance Coesite is an important geological mineral, yet it presents complicated phase transformations under compression. Earlier reports of pressure-induced amorphization have been later refined showing formation of various crystalline structures, including a high-pressure octahedral phase. Due to the complicated structure nature of coesite, we need to represent the system in a relatively large box. Previous first-principles calculations are limited, as only a small unit cell was employed. Here, we carried out molecular dynamics simulations based on an ab initio parameterized polarizable force field. This approach allows us accurate simulations with relatively large system sizes, which eventually enables us to provide a theoretical identification of multiple transformation pathways that have been discovered so far. High-pressure single-crystal X-ray diffraction method with precise control of hydrostatic conditions, typically with helium or neon as the pressure-transmitting medium, has significantly changed our view on what happens with low-density silica phases under pressure. Coesite is a prototype material for pressure-induced amorphization. However, it was found to transform into a high-pressure octahedral (HPO) phase, or coesite-II and coesite-III. Given that the pressure is believed to be hydrostatic in two recent experiments, the different transformation pathways are striking. Based on molecular dynamic simulations with an ab initio parameterized potential, we reproduced all of the above experiments in three transformation pathways, including the one leading to an HPO phase. This octahedral phase has an oxygen hcp sublattice featuring 2 × 2 zigzag octahedral edge-sharing chains, however with some broken points (i.e., point defects). It transforms into α-PbO2 phase when it is relaxed under further compression. We show that the HPO phase forms through a continuous rearrangement of the oxygen sublattice toward hcp arrangement. The high-pressure amorphous phases can be described by an fcc and hcp sublattice mixture.


Journal of Chemical Physics | 2017

Retention of contaminants Cd and Hg adsorbed and intercalated in aluminosilicate clays: A first principles study

F. Crasto de Lima; R. H. Miwa; Caetano R. Miranda

Layered clay materials have been used to incorporate transition metal (TM) contaminants. Based on first-principles calculations, we have examined the energetic stability and the electronic properties due to the incorporation of Cd and Hg in layered clay materials, kaolinite (KAO) and pyrophyllite (PYR). The TM can be (i) adsorbed on the clay surface as well as (ii) intercalated between the clay layers. For the intercalated case, the contaminant incorporation rate can be optimized by controlling the interlayer spacing of the clay, namely, pillared clays. Our total energy results reveal that the incorporation of the TMs can be maximized through a suitable tuning of vertical distance between the clay layers. Based on the calculated TM/clay binding energies and the Langmuir absorption model, we estimate the concentrations of the TMs. Further kinetic properties have been examined by calculating the activation energies, where we found energy barriers of ∼20 and ∼130 meV for adsorbed and intercalated cases, respectively. The adsorption and intercalation of ionized TM adatoms were also considered within the deprotonated KAO surface. This also leads to an optimal interlayer distance which maximizes the TM incorporation rate. By mapping the total charge transfers at the TM/clay interface, we identify a net electronic charge transfer from the TM adatoms to the topmost clay surface layer. The effect of such a charge transfer on the electronic structure of the clay (host) has been examined through a set of X-ray absorption near edge structure (XANES) simulations, characterizing the changes of the XANES spectra upon the presence of the contaminants. Finally, for the pillared clays, we quantify the Cd and Hg K-edge energy shifts of the TMs as a function of the interlayer distance between the clay layers and the Al K-edge spectra for the pristine and pillared clays.


RSC Advances | 2016

Adsorption of asphaltenes on the calcite (10.4) surface by first-principles calculations

Raphael da Silva Alvim; Filipe C. D. A. Lima; Verónica M. Sánchez; Thomas F. Headen; Edo S. Boek; Caetano R. Miranda

Asphaltenes play a key role in oil production and its exploration from natural reservoirs. In carbonate reservoirs, the calcite (10.4) surface retains asphaltenes. However, its aggregate structure and deposition process are not fully understood. Using first-principles calculations based on density-functional theory (DFT) with van der Waals (vdW) dispersion, we studied the adsorption of asphaltene, resin and resin–asphaltene dimer molecular models on the CaCO3 surface in the presence of a dielectric water–toluene environment. These large molecules impose a challenging description at the electronic level. Our calculations indicate that there is a minor steric hindrance in the effective interaction of the aromatic region of asphaltene on the calcite surface. However, aliphatic chains with sulphide groups can play a significant role on the adsorption process and its availability to receive electronic charge density from the surface. Accordingly, the preferential LUMO localized in the aromatic region of asphaltene may also allow the adsorption on the calcite surface and π–π stacking interactions. Initially, the resin molecule tends to be trapped during dimer formation with the asphaltene, whereas a significant intramolecular charge rearrangement due to the heteroatoms is necessary to increase the π–π stacking interactions. For the dimer, the adsorbed form of asphaltene favors more available electronic states to increase the likelihood of nanoaggregation. Therefore, changes in the continuum dielectric constant only had a minor effect on the calculated adsorption energies. Experimental work related to the oil–water interface in the presence of toluene show similar behavior during asphaltene adsorption. Our studies indicate that nanoaggregates are grown through resin and the calcite (10.4) surface selectively adsorbs the less polar asphaltenes from oil.


European Physical Journal B | 2015

The stability and interfacial properties of functionalized silica nanoparticles dispersed in brine studied by molecular dynamics

Lucas Stori de Lara; Vagner A. Rigo; Caetano R. Miranda


Microfluidics and Nanofluidics | 2016

Combining molecular dynamics and lattice Boltzmann simulations: a hierarchical computational protocol for microfluidics

Aline O. Pereira; Lucas Stori de Lara; Caetano R. Miranda


Journal of Physical Chemistry C | 2017

Theoretical Study of Hydrogen Adsorption on Au@Pd Icosahedral Nanoparticle

M. G. Sandoval; R. Luna; G. Brizuela; Aline O. Pereira; Caetano R. Miranda; P. Jasen


Computational Materials Science | 2017

Molecular simulations of cement based materials: A comparison between first principles and classical force field calculations

Sylvia M. Mutisya; James M. de Almeida; Caetano R. Miranda


Computational Materials Science | 2016

Hosting of La3+ guest ions in type-I Ge clathrates: A first-principles characterization for thermoelectric applications

Robert L. González-Romero; Caetano R. Miranda; Marcos A. Avila; Alex Antonelli


Journal of Physical Chemistry C | 2018

Fresh Molecular Look at Calcite–Brine Nanoconfined Interfaces

Alexsandro Kirch; Sylvia M. Mutisya; Verónica Sánchez; James Moraes de Almeida; Caetano R. Miranda

Collaboration


Dive into the Caetano R. Miranda's collaboration.

Top Co-Authors

Avatar

Alex Antonelli

State University of Campinas

View shared research outputs
Top Co-Authors

Avatar

Sylvia M. Mutisya

Universidade Federal do ABC

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Aline O. Pereira

Universidade Federal do ABC

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

F. Crasto de Lima

Federal University of Uberlandia

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge