|
||||||||||||||||||||||||||||||||||||||
Tag: ciência de materiais
SBPMat´s community people: interview with Reginaldo Muccillo.

On the morning of June 09th, in the Italian district of Montecatini Terme, the Materials researcher Reginaldo Muccillo, managing director of our SBPMat from 2012 to 2013, was sworn in as member of the World Academy of Ceramics (WAC). WAC is an international entity, with its main office located in Italy, dedicated to promoting progress in the field of ceramics, as well as to spread awareness regarding the social impact and cultural interactions offered by science, technology, history and arts in the field of ceramics.
Reginaldo Muccillo was one of the seventeen selected members in the 15th election process conducted by the WAC academicians, which recognizes the merit of those who substantially contributed to the field of ceramics. Being the only Brazilian member elected this time, Muccillo shared the induction ceremony with researchers and other professionals from China, Spain, the United States, Finland, Italy, Japan, Poland, Portugal and Sweden. The ceremony was held during the opening session of the International Conference on Modern Materials and Technologies (CIMTEC).
Researcher from the Materials Science and Technology Center of the Nuclear and Energy Research Institute (IPEN), Reginaldo Muccillo earned his undergraduate, Master’s and Doctoral degrees in Physics, at the University of São Paulo (USP). He did research stages abroad, first at the National Research Council in Ottawa (Canada) during his Doctorate, then, during his postdoctoral studies, at the Max Planck Institut fuer Festkoerperforschung, in Stuttgart (Germany) and the Institut National Politechnique de Grenoble (France). He was the (co) coordinator of seven issues of the Brazilian Electroceramics Symposium, the VII SBPMat Meeting (2008), and the 6th International Conference on Electroceramics (ICE 2013). He has been the main editor of the journal Cerâmica, an official publication of the Brazilian Association of Ceramics (ABCeram) for 15 years. He holds a 1A-level fellowship for research productivity in the Brazilian Council for Scientific and Technological Development (CNPq).
What follows is a brief interview with the scientist:
Tell us a bit about your history: what led you to become a scientist and work in the field of ceramic materials?
Already in my undergraduate studies, I left the Engineering course in USP’s Polytechnic School to attend Physics. Holding a research scholarship in the field of Nuclear Physics, I met renowned researchers in the USP’s Physics Institute, who effectively influenced me to pursue a scientific career. Once I graduated, I proceed to IPEN, for my Master in Solid-State Physics. Then, when I concluded my Master’s studies, I went to Canada for a research stage beeing part of my Doctorate course. After returning the IPEN, having defended my doctorate at the USP, I started to conduct researches with ceramic materials, moving from Solid-State Physics to Materials Science and Engineering.
In your opinion, what were your main contributions to the field of Materials?
Working in a research institute, I could focus all my time to conduct the research work itself, to raise resources in supporting entities (São Paulo Research Foundation – FAPESP, and CNPq) for improving the infrastructure of the laboratory (I am an experimental researcher dedicated to assembling and collecting data from equipment, analyzing such data and wrinting articles to be submitted to indexed and peer-reviewed journals), to train and instruct staff, to organize events, to edit scientific journals and to interact with the productive sector. In addition to the development of fundamental research in the field of Materials, my expertise allows me to seek applications in devices concerning many industrial sectors.
In your opinion, what are the main challenges to your current research topics in Materials Science and Engineering?
Explaining, modeling and providing theoretical equations to several physical and chemical phenomena that occur in the Ceramic Materials Science.
In your opinion, how did you receive the recognition of the international Ceramics research community, as expressed by your election as a WAC scholar?
Developing research work, training staff at undergraduate, master’s, doctoral and postdoctoral levels, assembling laboratories for the scientific community (multi-users), editing journals (the Cerâmica) in the field of ceramic materials, and researching materials for producing sensors and alternative energy sources, as well as, most recently, flash sintering.
Processo seletivo para mestrado e doutorado em Física e Química de Materiais na UFSJ (MG).
O Programa de Pós-graduação em Física e Química de Materiais (FQMat) divulga o Edital 001/2014 do processo seletivo – 2° semestre de 2014, para preenchimento de vagas de mestrado e doutorado.
As inscrições acontecerão no período de 18 a 27 de junho de 2014, 15h às 17h, Sala 3.05 do bloco C do Departamento de Ciências Naturais, Campus Dom Bosco – São João del Rei. As inscrições podem ser feitas via Sedex, desde que a correspondência seja postada até o dia 25 de junho de 2014.
Para mais informações sobre inscrição, documentos necessários, datas das provas e preenchimento da GRU, confira o edital no link
http://www.ufsj.edu.br/fqmat/processo_seletivo.php
Outras informações pelo telefone (32) 3379-2535 , (32) 3379-2444 ou pelo e-mail fqmat@ufsj.edu.br.
SBPMat newsletter. English edition. Year 1, issue 5.
|
||||||||||||||||||||||||||||||||||||||||||||
SBPMat e-newsletter. Year 1, issue 4.
|
||||||||||||||||||||||||||||||||||||||
SBPMat´s community people: interview with the scientist Sergio Mascarenhas.

Along his path as a scientist, Sergio Mascarenhas Oliveira, currently 85, has provided some important contributions to the improvement of the scientific research, mainly in Brazil, and for the Materials field in particular. Starting from Solid-state physics, pillar of the Materials Science, he covered several domains of knowledge, such as Molecular Biophysics and Medical Physics, to name a few. Impelled by the idea of fulfilling the social role of the scientist, which is related to social development, Mascarenhas promoted advances in science and technology with a significant impact on areas as farming, health and education.
An example that illustrates the work of Professor Mascarenhas is the recent development of a system to measure the intracranial pressure that is minimally invasive. The motivation for this came when the Professor was diagnosed with hydrocephaly in 2005 and, during treatment, had to be subject to skull drilling operations in order to measure his pressure. From this moment on, jointly with students and companies, as well as supported by several entities, he conducted a series of studies, which lead to a cheaper and minimally invasive system, applicable to a large range of patients.
Mascarenhas was born in Rio de Janeiro. From 1947 to 1951, he studied Physics at the Federal University of Rio de Janeiro State (UNIRIO) and Chemistry at the Federal University of Rio de Janeiro (UFRJ). After some time as a researcher for universities in the US, he decided to return to Brazil. In the country, he played a major role in the establishment and coordination of some institutions as, among others, the Physics and Chemistry Institute of São Carlos from São Paulo University (USP), the Federal University of São Carlos (UFSCar) and its Materials Engineering course (the first one to be offered in Latin America), as well as the instrumentation unit of the Brazilian Agricultural Research Corporation (Embrapa) and USP’s Institute of Advanced Studies of São Carlos and its International Studies and Projects Program for Latin America, which he still coordinates until this day.
Sérgio Mascarenhas is a Full Professor, now retired, at USP. He was also a visiting professor in the US at the Universities of Princeton and Harvard, and at MIT; at the National Autonomous University of Mexico, the Institute of Physical and Chemical Research in Japan, the London University (UK), and, in Italy, at the Abdus Salam International Centre for Theoretical Physics and at the University of Rome.
He has advised about 50 theses for master’s degrees and doctorates, and published approximately 200 articles and books. Among many awards and honors, it is worth mentioning the Grand Cross of the National Order of Scientific Merit (given in Brazil, by the President of the Republic); the Guggenheim Award and Fulbright Award (United States); the Yamada Foundation Award (Japan); the Brazilian award from Conrado Wessel Foundation in 2006 in the General Science category, and titles of Emeritus Professor and Honorary Doctorate degrees from several universities in Brazil and abroad. In 2012, it was time for the SBPMat to grant Professor Mascaranhas an award, the memorial lecture Joaquim Costa Ribeiro. Mascarenhas is a member of the Brazilian Academy of Sciences and the American Physical Society, and a founding member of the Latin American Academy of Science, and of the Academy of Science of the São Paulo State.
Below, there is a transcription of the interview Professor Mascarenhas gave us at 08:30 PM on March 26, once a work meeting was closed. The scientist told us a little about his background, the social role of the scientist, and his message to our younger readers.
Main contributions to science, technology and innovation, particularly in the Materials field in Brazil.
As I started doing sciences in Brazil in a moment when there was virtually no Materials, I was lucky enough to introduce this kind of research, both in applied and basic forms. So, I would say that, from the institutional perspective, an important contribution was the creation of the Condensed Matter Physics Group in the Physics Institute at USP São Carlos, in the 1960s. Thanks to a very intense exchange between USP São Carlos and the universities of Princeton and Carnegie Mellon in the United States, as well as groups from England and Germany, mainly from Stuttgart, we managed to establish a very strong researchers training program, which still exists today.
After that, I had the chance to be the first president of the Federal University of São Carlos (UFSCar), and then, I proposed the creation of the Materials Engineering Course. It was the first course of studies in Materials Engineering in Latin America, and was a great success, both on the academic and the business sides. So, these were two institutional contributions that led to the establishment of an actual School of Materials Science and Engineering in Brazil.
From the point of view of the research, there are contributions that I managed to do with the collaboration of many young and senior professors. First, the researches related to the defects in crystals, such as ionic crystals with color centers, through radiation or crystal growth with impurities. These ionic crystals displaying color centers were used later for optical memories. This was the result from a very strong collaboration between our group from São Carlos with the RCA laboratories in Princeton and Bell Labs, in the United States.
Another field we were pleased to see how it developed was the electrets, dielectric materials that can retain an electrical polarization for a very long time, up to 100 years, as we see in teflon. These electrets, then, were studied mainly by the group advised by professor Bernard Gross, who I was happy to bring to São Carlos. He worked with groups from MIT and Bell Labs and they developed the famous electrets microphone, which was used in all cell phones, telephones and many other applications. This was an application that gained a global status, coming from a product that was practically born in São Carlos.
Later, my extension of this concept of electrets to biological materials led to the concept of bioelectrets, which are biological materials also capable to retain an electrical polarization for a very long time. The concept of bioelectrets, I think, was one of the contributions that I was fortunate to do, and today is globally used. There is a book on electrets published by Springer publishing house [MASCARENHAS, S. 1979. Bioelectrets: electrets in biomaterials and biopolymers. Electrets – Topics in Applied Physics., Springer-Verlag, vol. 33 , p. 341 – 346] in which, in one of the chapters, I discuss this notion of biolectrets. The concept applies to proteins, DNA, polysaccharides. I think this concept is very important for being significant in Biology and Medicine.
Finally, we started working with concepts of Materials also in the field of Molecular Biophysics and Medical Physics. It happed due to the fact that I was invited by Nobel laureate Abdus Salam to conduct, in Trieste (Italy), a series of courses, for twelve years, in these two areas. These contributions were capable to spread the idea and the career in Medical Physics in many developing countries in Africa, Asia and Latin America. So, this was one of the contributions that please me the most.
But it all depends on people, especially young people. I always say that professors are only good when they have students that are even better than them. I had the joy of counting with students that were better than me, who went further and continued with the school of Condensed Matter Physics, such as in the case of professor Roberto Faria, who, nowadays, it the president of SBPMat and works in the frontier of conductive polymers – a revolution in the field of electronics, energy, pharmacology etc.
Current occupations and new frontiers of knowledge.
Lately, I have been concerned with examining phenomena under the point of view of complex phenomena, in which there is a great amount of variables and non-linear phenomena. For example, there is the brain, the Internet, the origins of life. So, the engineering of complex systems for Materials results in a number of very important effects, which are going to be gradually explored. This issue of complex systems permeates Engineering, Biology, Education, Agribusiness, which is one of the most important areas for humanity in the production of food, the issue of biomass, which is a very important problem for the production of energy, and the comprehension of the brain.
So, I think my function now it to draw the attention of the youth and of the research centers in developing countries to the importance of studying complex systems, which requires a lot of computer modeling, the understanding of what is artificial intelligence, Game Theory, chaotic systems, fractals… And the research on complex materials holds a crucial importance.
Another area that I think is going to progress more, and is an announced revolution, is the biomimetics field. You look to biological nature, which has worked for millions of years to produce materials as shells, bone, hair, organs, and learn how the evolution of the properties of these materials occurred. It is as we could open the large biological treasure of knowledge.
The social role of the scientist.
I think the social role of the scientist is essential for two reasons. First, if you look at the human history, all great evolutionary leaps in human thought came from basic science, which turned into technology. It is important for the scientist to provide, not only a voice to society, but some kind of self-awareness of the society, which is consolidated in science, technology and education policies. I think one of the best examples for that is looking at the convergence between science and technology. When Faraday’s electric motor was invented, it took about 40 years for it to be fully used. Nowadays, you cannot even think what would happen to society if there were no electric motors. When nuclear energy was discovered, in 10 to 15 years it already had some applications. And in the same year laser was invented, it was applied. Then, the convergence between science and technology is huge. It means that scientists and research are important to produce economic development, which leads to social development, which leads to cultural development, which leads to what Charles Percy Snow said was the third culture. In his book, “The two cultures”, he showed that, by the time of World War II, there was a very long distance from humanism to science and technology, even a lack of respect between these two players of the human development. But said distance has to converge into a third culture, in which it is possible to find a much more holistic view, not only of men, but also of the universe, as in the example of the Gaia theory of James Lovelock.
So, for the social development, research is the only weapon that men can hold to bring humanity to a stage of respect for nature, humanity itself and its role in the cosmos. I think, if we didn’t have universities producing researches and extension, and then taking their researches out, we wouldn’t see the formation of the virtuous cycle, which transforms knowledge into quality of life and new possibilities for men, for this homo sapiens sapiens that came out of caves and went to space.
A message to our younger readers, starting their careers.
I think this career, in Materials Science, Materials Engineering, Biomaterials, Complex Materials, is a huge world that is at dispose for the future of mankind, but this future depends on today’s youth, who can face its challenges and experience the great pleasure of building a more virtuous humanity through the research with Materials. If you start to think what Materials mean to human life, even in a more straightforward perspective, focused on happiness and wellbeing, our lives depend on materials. Our nutrition depends on materials, as well as communication, health, the manufacturing of equipment, machines, robots, ships and satellites. Thereby, materials really are a great source for innovation and wealth. The young people choosing this career are actually choosing to work for the future of science and technology.
Featured paper: Changing the properties and morphology of graphene nanoribbons with nitrogen.
The scientific paper by members of the Brazilian community in Materials research featured this month is:
Josue Ortiz-Medina, M. Luisa García-Betancourt, Xiaoting Jia, Rafael Martínez-Gordillo, Miguel A. Pelagio-Flores, David Swanson, Ana Laura Elías, Humberto R. Gutiérrez, Eduardo Gracia-Espino, Vincent Meunier, Jonathan Owens, Bobby G. Sumpter, Eduardo Cruz-Silva, Fernando J. Rodríguez-Macías, Florentino López-Urías, Emilio Muñoz-Sandoval, Mildred S. Dresselhaus, Humberto Terrones, Mauricio Terrones. Nitrogen-Doped Graphitic Nanoribbons: Synthesis, Characterization and Transport. Advanced Functional Materials 2013, 23, 3755-3762. DOI 10.1002/adfm.201202947.
Changing the properties and morphology of graphene nanoribbons with nitrogen
Multiple layers of graphene with the shape of ribbons (narrow and long) are called graphitic nanoribbons. These materials have been studied to control their properties by various methods, such as doping, in which are introduced atoms of “foreign” elements in the graphene carbon lattice.
In a study led by scientists at Pennsylvania State University with the participation of researchers from institutions in the United States, Mexico, Spain and Brazil, nitrogen-doped graphitic nanoribbons were manufactured by the chemical vapor deposition (CVD) method and showed new features, linked with the introduction of nitrogen, such as highest semiconductor performance, promising for applications in electronic devices, chemical reactivity and a very particular morphology on its edges. The research was published in the journal Advanced Functional Materials.
“This article showed by the first time that it is possible to make doping with nitrogen on the same synthesis by CVD of graphite nanoribbons, and that you can control the level of doping during synthesis,” highlights Fernando Rodríguez-Macías, foreign visiting professor at the Brazilian Federal University of Pernambuco (UFPE) and one of the authors of the scientific paper. A Mexican national, Rodríguez-Macías came to UFPE in 2012, during his sabbatical year to work as a foreign visiting professor in the Department of Fundamental Chemistry and in the Graduate Program in Materials Science of the University. “I have prolonged my stay for another year to continue until 2014 doing collaborative studies for the production of carbon nanostructures, of bionanotechnology and toxicity of nanomaterials,” says the professor. “I am also teaching preparation and characterization of materials,” he adds.
The doped nanoribbons
The article’s authors showed that different concentrations of nitrogen generate controlled changes in material behavior. In particular, scientists have proven that the more nitrogen introduced into the structure of graphene, the most predominant the semiconductor behavior of nanoribbons. As an explanation to this phenomenon, the researchers suggested, based on theoretical calculations, that nitrogen atoms of doped nanoribbons act as scattering centers of electrons and decrease the conductive behavior of undoped graphene. “The control of doping level allows you to change the electrical properties of the nanoribbons, which can be useful for applications in transistors and other electronic devices,” says Rodríguez-Macías.
In addition, the paper also shows that the reactivity of nanoribbons can change with the doping level. Pure graphene, explains UFPE’s visiting professor, is very inert and has limited interactions with many chemical substances; on the other hand, nanoribbons doped with nitrogen are more reactive, which makes them useful for applications in sensors and catalysis.
As to the morphology, the article’s authors found that the nitrogen-doped nanoribbons have loops on their edges, uniting different graphene sheets. “This morphology is not presented by undoped graphite nanoribbons,” says Rodríguez-Macías.
This figure, sent by Professor Fernando Rodríguez-Macías, shows the nitrogen-doped graphitic nanoribbons in three scales. The scanning electron microscopy (top left corner) shows how these ribbons are made up of several layers and feature a curved surface with roughness. The transmission electronic microscopy (bottom left corner) shows that the nanoribbon layers are graphene sheets. The high resolution transmission electronic microscopy (right) shows that the layers of graphene on the nanoribbons edges form loops uniting different graphene sheets.
Collaborators
Almost all work of materials synthesis of the paper of Advanced Functional Materials was developed at Pennsylvania State University; the characterization was done in collaboration with other researchers and laboratories, reports UFPE’s visiting professor.
The participation of UFPE in the article happened through the doctoral student Miguel Angel Pelagio-Flores in the analysis and theoretical modeling of doped nanoribbons, and through professor Fernández-Macías himself, who, in addition to having participated in the discussion of results and review of the article from his office at UFPE, was doctoral advisor of the first author of the article, Josué Ortiz-Medina, while professor of a Mexican institution, IPICYT. “Ortiz-Medina did most of the experimental work of the article, besides being an important part of the characterization and theoretical studies of these new nanomaterials, when he was in exchange at Penn State in the laboratory of professor Terrones,” contextualizes the professor.
In total, 19 authors sign the article, among them MIT’s Professor Mildred Dresselhaus, reference in carbon science.
Boletim SBPMat – edição 16 – dezembro 2013.
|
|||||||||||||||||||||||||||||||||||||||||
Artigo em destaque: Pontos quânticos desenvolvidos para LEDs mais eficientes.
O artigo científico de membros da comunidade brasileira de pesquisa em Materiais em destaque neste mês é:
Wan Ki Bae, Young-Shin Park, Jaehoon Lim, Donggu Lee, Lazaro A. Padilha, Hunter McDaniel, Istvan Robel, Changhee Lee, Jeffrey M. Pietryga & Victor I. Klimov. Controlling the influence of Auger recombination on the performance of quantum-dot light-emitting diodes. Nature Communications 4, article number 2661, published 25 October 2013. doi:10.1038/ncomms3661.
Texto de divulgação:
Pontos quânticos desenvolvidos para LEDs mais eficientes
Um trabalho de pesquisa publicado no mês de outubro na Nature Communications, revista científica de conteúdo aberto do grupo Nature, resultou num material que aumenta dezenas de vezes a eficiência de LEDs de pontos quânticos ao diminuir a influência do efeito Auger, um dos principais limitadores da eficiência desses dispositivos que apresentam grande potencial para serem usados em iluminação, entre outras aplicações. O trabalho foi realizado no Grupo de Nanotecnologia e Espectroscopia Avançada do Laboratório Nacional de Los Alamos, localizado no sul dos Estados Unidos, com a participação de um doutor brasileiro, Lázaro Padilha, e com a colaboração de grupos da Coreia.
“O resultado veio depois de mais de um ano de pesquisa sobre como efetivamente minimizar o efeito Auger em pontos quânticos”, relata Padilha, atualmente professor do Instituto de Física da Unicamp, que chegou a Los Alamos em 2010 para fazer um estágio de pós-doutorado. O trabalho que gerou o paper na Nature Communications, além de outros artigos em periódicos de alto fator de impacto como Nano Letters e ACS Nano, começou no final de 2011 e, na sua primeira etapa, visou entender o processo físico para minimizar a influência do chamado “efeito Auger” ou “recombinação Auger” nos pontos quânticos.
Os pontos quânticos, cristais semicondutores de alguns nanometros de tamanho, apresentam propriedades que possibilitam a emissão de luz com brilho intenso e cores puras e podem ser fabricados usando técnicas simples e de baixo custo. Por esses motivos, essas nanopartículas são materiais interessantes para a fabricação de LEDs. Desde a primeira demonstração de LEDs de pontos quânticos, ocorrida em 1994 (Nature 370, 354 – 357, 04 August 1994; doi:10.1038/370354a0), esses dispositivos têm sido objeto de pesquisas visando otimizar sua capacidade de converter eletricidade em luz.
Nos LEDs, a emissão de luz se produz quando, ao se introduzir energia no dispositivo por meio de corrente elétrica, ocorrem recombinações nos átomos do material emissor. Especificamente, elétrons próximos ao núcleo do átomo saem de seu lugar deixando vagas, as quais são preenchidas por elétrons mais distantes, dotados de mais energia. A energia excedente pode sair em forma de fóton, ocorrendo a desejada emissão de luz, ou pode ser transmitida a um terceiro elétron, que será ejetado do átomo. Esta segunda possibilidade constitui o efeito Auger, que pode ser visto como um concorrente da emissão de luz no uso da energia.
Nanoengenharia dos pontos quânticos
Depois de compreender como minimizar a recombinação Auger nos pontos quânticos do ponto de vista físico e constatar que impacta significativamente na eficiência dos LEDs, o grupo de Los Alamos se propôs a desenvolver o material que teria o melhor desempenho frente a esse efeito. “Eu trabalhei nos estudos de espectroscopia para entender os processos físicos que levariam a um melhor desempenho dos materiais como base para LEDs”, diz Lázaro Padilha.
O desenvolvimento do material foi feito a partir de pontos quânticos compostos por um núcleo de seleneto de cádmio (CdSe) e uma casca de sulfeto de cádmio (CdS). Para conseguir a redução da influência do efeito Auger, os cientistas aplicaram duas estratégias de nanoengenharia: a variação da espessura da casca e a introdução de uma camada composta por uma liga de zinco, cádmio e enxofre (ZnCdS) entre o núcleo e a casca.
Após concluir, em Los Alamos, o desenvolvimento do material base, os colaboradores da Coreia do construíram LEDs com uma arquitetura na qual a camada emissora, formada pelos pontos quânticos, ficou inserida entre as camadas de transporte de cargas negativas e positivas, sendo uma inorgânica e a outra orgânica, respectivamente, como mostra a figura a seguir, extraída do artigo da Nature Communications:

“Uma vez encontrado o material que teria o melhor efeito, foram fabricados os LEDs e pudemos confirmar os resultados esperados”, conta Padilha. A confirmação ocorreu através de uma série de medidas espectroscópicas dos pontos quânticos dentro dos dispositivos.
De acordo com Padilha, com os novos materiais desenvolvidos, os cientistas conseguiram obter LEDs de pontos quânticos até 10 vezes mais eficientes, com uma taxa de conversão de energia elétrica em energia luminosa da ordem de 8%.
Seleção da Pós-graduação em Física e Química de Materiais da Universidade Federal de São João del Rei (MG).
O Programa de Pós-graduação em Física e Química de Materiais (FQMat) da Universidade Federal de São João del Rei (MG) divulga o Edital 003/2013 do processo seletivo – 1° semestre de 2014, para preenchimento de vagas de mestrado e doutorado.
As inscrições acontecem no período de 15 a 30 de janeiro de 2014, das 09 às 11h e 14h às 17h, na Secretaria do Programa FQMat, Sala 2.19, Bloco A do Departamento de Ciências Naturais (DCNAT), Campus Dom Bosco – São João del Rei. As inscrições podem ser feitas via Sedex, desde que a correspondência seja postada até o dia 25 de janeiro de 2014.
Para mais informações sobre inscrição, documentos necessários, datas das provas e preenchimento da GRU, confira o edital no link http://www.ufsj.edu.br/fqmat/processo_seletivo.php
Outras informações pelo telefone (32) 3379-2535 ou pelo e-mail fqmat@ufsj.edu.br.
