Marcia Barbosa

• doctor in physics
• Professor (Full) at Federal University of Rio Grande do Sul

Nanoporous membranes are being explored as efficient materials for water filtration and desalination applications. In this study, we analyzed the behavior of pores within a freestanding hexagonal boron nitride ( h -BN) monolayer in contact with water molecules. Our investigation revealed that triangular and rhombic pores induce wrinkles in non-depo...

Understanding the adsorption of water and characterizing the water film formed within nanostructures are essential for advancements in fields such as nanofluidics, water purification, and biosensing devices. In our research, we focus on studying the condensation and transport of water through an alumina membrane with nanopores of varying wettabilit...

Through Monte Carlo simulations and the Associating Lattice Gas Model, the phases of a two-dimensional fluid under hydrophilic confinement are evaluated. The model, in its unconfined version, reproduces the anomalous behavior of water regarding its density, diffusion, and solubility, among other dynamic and thermodynamic properties. Extreme confine...

Water is used as a main solvent in model systems containing bioorganic molecules. Choosing the right water model is an important step in the study of biophysical and biochemical processes that occur in cells. In the present work, we perform molecular dynamics simulations using two distinct force fields for water-the rigid model TIP4P/2005, where on...

In this work we have compared the self-perceived competences of future chemistry teachers who are pursuing teacher training courses in all the regions of Brazil taking the following factors into account: sex, age and Brazilian region origin. A quantitative exploration was adopted and the data were collected using the Self-Perceived Competences of T...

Context: In this paper, we have addressed two issues that are relevant to the interaction of water in pristine and vacant graphene through first-principles calculations based on the Density Functional Theory (DFT). The results showed that for the interaction of pristine graphene with water, the DOWN configuration (with the hydrogen atoms facing do...

In this work we explore the one-dimensional extended Hubbard model as a fluid system modelling liquid phases of different densities. This model naturally displays two length scales of interaction, which are connected with waterlike anomalies. We analyze the density anomaly as a function of the model parameters, namely the hopping, on-site and first...

In this work, we investigate the water capture process for functionalized carbon nanocones (CNCs) through molecular dynamic simulations in the following three scenarios: a single CNC in contact with a reservoir containing liquid water, a single CNC in contact with a water vapor reservoir, and a combination of more than one CNC in contact with vapor...

In this study, using non-equilibrium molecular dynamics simulation, the flow of water in deformed carbon nanotubes is studied for two water models TIP4P/2005 and SPC/FH. The results demonstrated a non-uniform dependence of the flow on the tube deformation and the flexibility imposed on the water molecules, leading to an unexpected increase in the f...

Abstract This article performs an analysis of female participation in science, in the Brazilian system of graduate studies and scientific research as a case study. This is relevant because science is a central supporting structure for modern societies and, therefore, a detailed analysis of the scientific power structure behind academic policy creat...

We modeled the change in the temperature of maximum density (TMD) of a waterlike solvent when small amounts of solute are added to the mixture. The solvent is modeled as a two length scales potential, which is known to exhibit waterlike characteristic anomalies, while the solute is chosen to have an attractive interaction with the solvent which is...

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 number of hydrogen bonds that water forms depends on the structure of the nanotube, directly affecting the diffusion o...

In this work, we propose a method to harvest liquid water from water vapor using carbon nanocones. The condensation occurs due to the presence of hydrophilic sites at the nanocone entrance. The functionalization, together with the high mobility of water inside nanostructures, leads to a fast water flow through the nanostructure. We show using molec...

This article explores the gender scenario regarding proposal and concessions of a research productivity grant from a Brazilian funding agency (Conselho Nacional de Desenvolvimento Científico e Tecnológico – CNPq) in the fields of physics and nursing. Data for this investigation was provided by the funding agency and refers to the total number of gr...

We modeled the change in the temperature of maximum density (TMD) of a water-like solvent when small amounts of solute are added to the mixture. The solvent is modeled as a two length scales potential, which is known to exhibit water-like characteristic anomalies, while the solute is chosen to have an attractive interaction with the solvent which i...

Resumo A democratização no acesso à ciência almejada com o Acesso Aberto vem acompanhada do pagamento de Article Processing Charges. Em um contexto de escassez de recursos financeiros, “pagar para publicar” se torna um desafio para países em desenvolvimento como o Brasil. Dada a inexistência de uma política sobre financiamento dessa despesa para as...

In this work, the dielectric behavior of water inside charged nanoslit of graphene is studied to analized the water molecules under electrical confinement; through polarizing the nanoslit of graphene, creating an electric field inside the nanopore. How the water molecules are structured under this type of electrical confinement is studied with two...

In this work we propose using molecular dynamic simulations a method to harvest liquid water from vapor using carbon nanocones. The condensation occurs due to the presence of hydrophilic sites at the nanocone entrance. The functionalization together with the high mobility of water inside nanostructures leads to fast water flow through the nanostruc...

We study the change in the temperature of maximum density (TMD) of a water-like solvent when small amounts of solute are added to the mixture. The water is modeled as a two length scales potential, which is known to exhibit water-like characteristic anomalies, while the solute is chosen to have an attractive interaction with the solvent. If the sol...

This review is devoted to discussing recent progress on the structure, thermodynamic, reactivity, and dynamics of water and aqueous systems confined within different types of nanopores, synthetic and biological. Currently, this is a branch of water science that has attracted enormous attention of researchers from different fields interested to exte...

The expansion of open access publications has been correlated with specific government policies in many countries. The evolution in these cases is understandable within the framework of funding regulations. However, this is not the case for Brazil, where no regulation is currently in place. The unusually high percentage of open access publications...

One of the most promising applications in nanoscience is the design of new materials to improve water permeability and selectivity of nanoporous membranes. Understanding the molecular architecture behind these fascinating structures and how it impacts the water flow is an intricate but necessary task. We studied here, the water flux through multi-l...

The transformation of women's role in society has been systematically studied. Numerous authors point out that among the factors of extreme relevance to this fact, the main is the increased presence of women in the formal job market. Researches also reveal that the increase in quantity is not reflected equally in all productive sectors nor the egal...

Artigo publicado no blog do jornal O Globo sobre a história da descoberta do efeito mpemba. Cientistas de todo o mundo ainda buscam a compreensão teórica deste efeito. https://blogs.oglobo.globo.com/ciencia-matematica/post/efeito-mpemba-uma-esquisitice-da-agua-descoberta-por-uma-crianca.html

Short-chain alcohols at high dilution are among the very few solutes that enhance the anomalous behavior of water, in particular the value of the temperature of maximum density. This peculiar feature, first discovered experimentally in the early twenties, has remained elusive to a full explanation in terms of atomistic models. In this paper, we fir...

Nanoscale materials are promising desalination technology. While fast water flow in nanotubes is well understood, this is not the case for water permeability in single-layer membranes. The advances in nanofluidics opened up the possibility to shift the permeability–selectivity tradeoff. The physical-chemical balance between nanopore size, shape, an...

Harassment is a common problem in many institutions, including academic ones. It creates invisible barriers for attracting and maintaining women and other minorities at academia. In this work, we quantify and qualify this problem in one of the biggest universities of Brazil, the Federal University of Rio Grande do Sul (UFRGS). We applied a spontane...

We study the impact of the induced pressure fields on the water flow and salt rejection in nanopores produced in MoS2 membranes. We observe that the water permeability and the salt rejection are not impacted by the distance between the pores. This result contradicts the continuous fluid mechanics calculations in microfilters, which indicates the ex...

Beyond graphene-based membranes, for water desalination, a vast horizon of new materials has been discovered for solutes separation from water. In this realm, the transition-metal dichalcogenides (TMDs) molybdenum and tungsten disulfide (MoS2 and WS2, respectively) stand as promising two-dimensional (2D) materials. Their tailoring for nanofluidics...

This article will carry out an analysis of female participation in science,considering the Brazilian system of graduate studies and scientific research as a casestudy. Goals. Considering that science is a central supporting structure for modernsocieties, a detailed analysis of the scientific power structure behind academic policycreation can reveal...

In this article, we investigate, through molecular dynamics simulations, the diffusion behavior of the TIP4P/2005 water confined in pristine and deformed carbon nanotubes (armchair and zigzag). To analyze different diffusive mechanisms, the water temperature was varied as 210 ≤ T ≤ 380 K. The results of our simulations reveal that water presents a...

Nanoscale materials are a promising desalination technology. While fast water flow in nanotubes is well understood, this is not the case for water permeability in single-layer membranes. The physical-chemical balance between nanopore size, shape, and charge might be the answer.

Correction for ‘Salt parameterization can drastically affect the results from classical atomistic simulations of water desalination by MoS 2 nanopores’ by João P. K. Abal et al. , Phys. Chem. Chem. Phys. , 2020, 22 , 11053–11061, DOI: 10.1039/d0cp00484g.

Considering the thermodynamics of bosons in a lattice described by the Bose-Hubbard Hamiltonian, we report the occurrence of anomalous double peaks in their specific heat dependence on temperature. This feature, usually associated with a high geometrical frustration, can also be a consequence of a purely energetic competition. By employing self-ene...

The shift in water security demands improvements in alternative solutions such as saltwater desalination. One of the most efficient technologies in this scope is the reverse osmosis systems, a technology based on a membrane separation process. MoS$_2$ nanoporous membranes are gained attention as a promise for the next-generation high selective and...

In this article we investigate through molecular dynamics simulations the diffusion behavior of the TIP4P/2005 water when confined in pristine and deformed carbon nanotubes (armchair and zigzag). To analyze different diffusive mechanisms, the water temperature was varied from 210 ≤ T ≤ 380 K. The results of our simulations reveal that water present...

In this article we investigate through molecular dynamics simulations the diffusion behavior of the TIP4P/2005 water when confined in pristine and deformed carbon nanotubes (armchair and zigzag). To analyze different diffusive mechanisms, the water temperature was varied from $210\leq T\leq 380$~K. The results of our simulations reveal that water p...

Water, the substance of life, is known for its myriad of anomalous properties, whose origins are still the subject of intense debates. In order to provide a different insight into this problem, we show how its density anomaly can be reproduced using a quantum simulator. In particular, we demonstrate that the Bose-Hubbard model, a paradigm system in...

Short-chain alcohols at high dilution are among the very few solutes that enhance the anomalous behavior of water, in particular the value of the temperature of maximum density. This peculiar feature, first discovered experimentally in the early sixties, has remained elusive to a full explanation in terms of atomistic models. In this paper, we firs...

Women are underrepresented in science and their participation decreases as the career progresses, an international phe-nomenon clearly displayed in a scissors graph. This decrease is usually attributed to maternity, lower number of publicationsand less ability of receiving grants. Here we present a comprehensive study of the Brazilian science and t...

Molecular Dynamics simulations of water confined in carbon nanotubes subjected to external electric fields show that water mobility strongly depends on the confining geometry, the intensity and directionality of the electric field. While fields forming angles of 0° and 45° slow down the water dynamics by increasing organization, perpendicular field...

Water scarcity is a reality in our world, and scenarios predicted by leading scientists in this area indicate that it will worsen in the next decades. However, new technologies based in low-cost seawater desalination can prevent the worst scenarios, providing fresh water for humanity. With this goal, membranes based in nanoporous materials have bee...

In this work, a two dimensional system of polymer-grafted nanoparticles is analyzed using large-scale Langevin dynamics simulations. Effective core-softened potentials were obtained for two cases: one where the polymers are free to rotate around the nanoparticle core and a second where the polymers are fixed, with a 45° angle between them. The use...

Water scarcity is a reality in our world, and scenarios predicted by leading scientists in this area indicate that it will worsen in the next decades. However, new technologies based in low-cost seawater desalination can prevent the worst scenarios, providing fresh water for humanity. With this goal, membranes based in nanoporous materials have bee...

We propose a new flexible force field of water, from the parameters of the SPC/ϵ model. The model includes, in addition to the Lennard-Jones and electrostatic parameters the flexibility in OH bonds and angle. The parameters are the result of the optimization in order to reproduce the experimental values of the density and dielectric constant of wat...

We use molecular dynamics simulations to study the diffusion of water inside deformed carbon nanotubes with different degrees of deformation at 300 K. We found that the number of hydrogen bonds that water forms depends on nanotube topology, leading to enhancement or suppression of water diffusion. The simulation results reveal that more realistic n...

This paper focuses on gender equality in the Brazilian energy sector, including both public and private sectors. It provides an assessment on how gender inequality impacts on women, and how their presence in decision-making roles can lead to more diverse and better practices that can positively influence a sustainable transition towards social incl...

This paper focuses on gender equality in the Brazilian energy sector, including both public and private sectors. It provides an assessment on how gender inequality impacts on women, and how their presence in decision-making roles can lead to more diverse and better practices that can positively influence a sustainable transition towards social incl...

The phase behavior of a two dimensional fluid confined within hydrophobic walls is obtained by Monte Carlo simulations. The fluid is described by the associating lattice gas model which reproduces the density and diffusion anomalous behavior of water. The confined fluid exhibits a liquid-liquid critical temperature which decreases with the decrease...

We analyze the influence of different groups on the intermolecular energy of aromatic homodimers and on the interaction between a single aromatic molecule and a graphene surface. The analysis is performed for benzene, phenol, catechol, and dopamine. For calculating the energies, we employ density functional theory within the local density approxima...

In this work, a two dimensional system of polymer grafted nanoparticles is analyzed using large-scale Langevin Dymanics simulations. Effective core-softened potentials were obtained for two cases: one where the polymers are free to rotate around the nanoparticle core and a second where the polymers are fixed, with a $45^\circ$ angle between them. T...

We analyze the influence of different groups on the intermolecu-lar energy of aromatic homodimers and on the interaction between a single aromatic molecule and a graphene surface. The analysis is performed for ben-zene, phenol, catechol and dopamine. For calculating the energies we employ density functional theory within the local density approxima...

We investigate by molecular dynamics simulations the mobility of the water located at the DNA minor and major grooves. We employ the TIP3P water model, and our system is analyzed for a range of temperatures 190–300 K. For high temperatures, the water at the grooves shows an Arrhenius behavior similar to that observed in the bulk water. At lower tem...

We investigate the diffusion and structure of TIP4P/2005 water confined in carbon nanotubes under the effect of electric field. For nanotubes with distinct diameters we vary the intensity and the direction of the electric field. We show that the nanotube diameter, the field intensity and the relative direction between field and tube axis change the...

Resumo O teorema de Nöther é revisitado com dois objetivos: ressaltar a significado desses resultados para a física contemporânea e ao mesmo tempo apresentar aspectos da biografia de Emmy Nöther, enfatizando a misoginia sofrida na sua atividade científica, a despeito da reconhecida importância, ainda em vida, de seus trabalhos. Sob esta perspectiva...

We show that the Bose-Hubbard Model exhibits an increase in density with temperature at fixed pressure in the regular fluid regime and in the superfluid phase. The anomaly at the Bose-Einstein condensate is the first density anomaly observed in a quantum state. We propose that the mechanism underlying both the normal phase and the superfluid phase...

HEADLINES: • The energy sector is one of the worst sectors in Brazil in terms of gender equality. Severe inequalities were identified across the entire sector. There is a lack of a gender perspective in the hiring and promotion processes, and little involvement of women in energy access projects at the community level. • Although women’s particip...

In this work, we employed Molecular Dynamics simulations of a mixture of 1:1 and 3:1 salts in order to explore the flocculation as a prominent factor in desalination through nanoporous membranes. The NaCl rejection by the nanomembranes is enhanced due to the addition of the multivalent cation from ~70% to 100%. Our findings indicate that the mechan...

We use molecular dynamics simulations to study the diffusion of water inside deformed carbon nanotubes with different degrees of deformation at 300 K. We found that the number of hydrogen bonds that water forms depends on nanotube topology, leading to enhancement or suppression of water diffusion. The simulation results reveal that more realistic n...

The article processing charge (APC) provides economic sustainability for scientific journals that publish in open access (OA). In this work, documents published in OA between 2012 and 2016 by authors with Brazilian affiliation are identified, the profile of these publications is analyzed and the cost of APC is estimated. In order to do so, data fro...

We propose a new flexible force field for water. The model in addition to the Lennard-Jones and electrostatic parameters, includes the flexibility of the OH bonds and angles. The parameters are selected to give the experimental values of the density and dielectric constant of water at at 1 bar at 240K and the dipole moment of minimum density. The F...

Recent studies have shown that diversity in race and gender is important to improve competitiveness, creativity and innovation. However, many studies have shown that the universe of science is not diverse in none of these criteria. In this work, we quantify the gender and geographic diversity in the Brazilian science. We study in detail the profile...

We use molecular dynamics simulations to study the diffusion of water inside deformed carbon nanotubes, with different degrees of eccentricity at 300K. We found a water structural transition between tubular-like to single-file for the (7,7) nanotubes associated with a change from a high to low mobility regimes. The water which in the undeformed (9,...

We use molecular dynamics simulations to study the diffusion of water inside deformed carbon nanotubes, with different degrees of eccentricity at 300K. We found a water structural transition between tubular-like to single-file for the (7,7) nanotubes associated with a change from a high to low mobility regimes. The water which in the undeformed (9,...

We investigate the structural, thermodynamic, and dynamic behavior of a two-dimensional (2D) core-corona system using Langevin dynamics simulations. The particles are modeled by employing a core-softened potential which exhibits waterlike anomalies in three dimensions. In previous studies in a quasi-2D system a new region in the pressure versus tem...

Using molecular dynamic simulations we show that single-layers of molybdenum disulfide (MoS$_2$) and graphene can effectively reject ions and allow high water permeability. Solutions of water and three cations with different valence (Na$^+$, Zn$^{2+}$ and Fe$^{3+}$) were investigated in the presence of the two types of membranes and the results ind...

Using molecular dynamic simulations we show that single-layers of molybdenum disulfide (MoS$_2$) and graphene can effectively reject ions and allow high water permeability. Solutions of water and three cations with different valence (Na$^+$, Zn$^{2+}$ and Fe$^{3+}$) were investigated in the presence of the two types of membranes and the results ind...

The pressure versus temperature phase diagram of a system of particles interacting through a multiscale shoulder-like potential is exactly computed in one dimension. The N-shoulder potential exhibits N density anomaly regions in the phase diagram if the length scales can be connected by a convex curve. The result is analyzed in terms of the convexi...

The slip of a fluid layer in contact with a solid confining surface is investigated for different temperatures and densities using molecular dynamic simulations. We show that for an anomalous water-like fluid the slip goes as follows: for low levels of shear, the defect slip appears and is related with the particle exchange between the fluid layers...

We perform Molecular Dynamics simulation of a two dimensional core-corona system to investigate the differences between the thermodynamic and dynamic behavior of the molecular fluids and the Brownian systems. The particles are modeled using a core-softened potential that exhibits waterlike anomalies for the 3D and quasi-2D molecular fluids. Our res...

We have used Molecular Dynamics simulations to investigate the structure and dynamics of TIP4P/2005 water confined inside nanotubes. The nanotubes have distinct sizes and were built with hydrophilic or hydrophobic sites, and we compare the water behavior inside each nanotube. Our results shows that the structure and dynamics are strongly influenced...

The force field of Potassium Bromide, KBr/ε. Improve all the oldest force field since the crystal density and structure, as well as, the density, the viscosity and the dielectric constant of the solution in water were computed and compared with the experiments and other atomistic models. Next, the transferability of the KBr/ε and of the NaCl/ε mode...

This article presents an analysis of Brazilian research on High Energy Physics (HEP) indexed by Web of Science (WoS) from 1983 to 2013. Scientometric indicators for output, collaboration and impact were used to characterize the field under study. The results show that the Brazilian articles account for 3% of total HEP research worldwide and that th...

We performed molecular dynamics simulations of water confined within AlPO4-54 nanotubes. AlPO4-54 is an artificial material made of AlO4 and of PO4 in tetrahedra arranged in a periodic structure forming pores of approximately 1.3 nm in diameter. This makes AlPO4-54 an excellent candidate for practical applications, such as for water filtration and...

Starting from an anomalous monomeric system, where particles interact via a two-scale core-softened potential, we investigate how the system properties evolve inasmuch as particles are put together to form polymers whose chain size varies from 4 up to 32 monomers. We observed that the density and diffusion anomaly regions in the pressure versus tem...

Atomic Force Microscopy analysis is employed to study the geometrical and topological properties of $3000$kbp DNA molecules fixed in mica substrates with $MgCl_{2}$. We found that the aggregates on the substrate surface for certain salt concentrations form a honeycomb stable structure with the addition of salt. The honeycomb, and the transition to...

O número de revistas de acesso aberto aumentou ao longo dos últimos anos e o pagamento de taxa de processamento de artigo (Article Processing Charge) tem sido o modelo de sustento adotado por algumas editoras. O objetivo do estudo é averiguar a existência de uma política brasileira de financiamento público para a publicação de artigos em acesso abe...

We perform an extensive computational study of binary mixtures of water and short-chain alcohols resorting to two-scale potential models to account for the singularities of hydrogen bonded liquids. Water molecules are represented by a well studied core softened potential which is known to qualitatively account for a large number of water's characte...

We perform an extensive computational study of binary mixtures of water and short-chain alcohols resorting to two-scale potential models to account for the singularities of hydrogen bonded liquids. Water molecules are represented by a well studied core softened potential which is known to qualitatively account for a large number of water's characte...

Uma avalia¸c˜ao das atividades da Comiss˜ao de Rela¸c˜oes de Gˆenero da Sociedade Brasileira de F´ísica ´e apresentada. A ˆenfase est´a nos eixos de a¸c˜oes b´asicas, onde se destaca as atividades de divulga¸c˜ao cient´ıfica em f´ısica voltadas para as meninas nas escolas.

Neste artigo iremos discutir alguns comportamentos pouco usuais da ´agua. Iremos mostrar igualmente como estas anomalias n˜ao somente s˜ao importantes para a manuten¸c˜ao da vida como podem ser usadas para resolver o problema de falta de ´agua pot´avel.

The correct description of the ionic interaction and stable equilibrium of the simulations of biomolecular structure, dynamics, folding, catalysis, and function, an accurate model of the monovalent ions is very important. The force field needs to reproduce coincident many properties of ions, like their structure, solvation, and moreover both the in...

We investigate through non-equilibrium Molecular Dynamics simulations the structure and flow of fluids in functionalized nanopores. The nanopores are modeled as cylindrical structures with solvophilic and solvophobic sites. Two fluids are modeled. The first is a standard Lennard Jones fluid. The second one is modeled with a isotropic two-length sca...

Molecular Dynamic and Monte Carlo studies are performed in a family of core-softened (CS) potential, composed by two length scales: a repulsive shoulder at short distances and the another a variable scale, that can be repulsive or strongly attractive depending on the parameters used. The density, diffusion and structural anomalous regions in the pr...

Molecular Dynamic and Monte Carlo studies are performed in a family of core-softened (CS) potential, composed by two length scales: a repulsive shoulder at short distances and the another a variable scale, that can be repulsive or strongly attractive depending on the parameters used. The density, diffusion and structural anomalous regions in the pr...

A lattice model for the study of mixtures of associating liquids is proposed. Solvent and solute are modeled by adapting the associating lattice gas (ALG) model. The nature of interaction solute/solvent is controlled by tuning the energy interactions between the patches of ALG model. We have studied three set of parameters, resulting on, hydrophili...