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5th Brazilian Materials Research Society Meeting (SBPMat)
October 8 - 12, 2006 | Florianópolis, Brazil
In co-operation with the Brazilian MRS
(Sociedade Brasileira de Pesquisas em Materiais) |
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Postscript
The 5th Brazilian Materials Research Society Meeting (SBPMat) concluded on Thursday, October 12, after five days of activities, including the plenary talks, various scientific and technical presentations, special events, poster sessions, the conference dinner and the exhibit. Well over 900 people attended the meeting.
The venue - Costao do Santinho - a lovely beach resort near the city of Florianópolis, Brazil, was the ideal location to discuss the latest materials science and engineering research in Brazil and around the world. A sizeable international contingent of meeting attendees mingled with Brazilian attendees at the conference, adding to the meeting atmosphere, promoting networking and discussions. There were also strong representations by women scientists and engineers, as well as by students.
We hope you have enjoyed receiving the Meeting Scene e-mails from Brazil. To subscribe to our other e-newsletters and alerts, please visit the MRS website and login to your account. Please direct any comments and suggestions to the Editor. The Meeting Scene e-mails from Brazil are also archived on the MRS website. Additional coverage of the meeting is presented below.
CLOSING SESSION
On Thursday morning, after oral and poster sessions, a special closing session was held to formally bring the conference to a close. The meeting chair, Prof.
Aloisio Nelmo Klein, and the president of the Brazilian MRS, Prof.
Fernando Lázaro, both speaking in Portuguese as well as English, thanked all attendees for making the conference a complete success. Members of the organizing committee and staff who helped organize the conference were thanked and presented with a special gift. Finally, everyone was invited to attend the next Brazilian MRS meeting slated to be held in 2007 in the city of Natal in northern Brazil. The Brazilian MRS meeting in 2009 will also include the IUMRS ICAM meeting for the first time.
TECHNICAL TALKS
Symposium A: Tribology and Surface Engineering
A623: Keynote Lecture: Three Approaches to Understanding Sliding Friction and Wear
 Prof. David Rigney of The Ohio State University gave an interesting presentation on sliding friction and wear that included molecular-dynamic simulations of effects that occur when two materials slide past one another. Rigney showed movies in which clear vortices formed at the interface between two materials. He compared these with similar patterns in fluid flow, as sometimes revealed by clouds in the atmosphere.
The addition of soft lubricating particles to one of the materials improved the lubrication properties even after mixing. High energy hard particles tend to clump at the interface and could clearly be seen to rotate as clumps. Future work includes the validation of molecular dynamic predictions via high velocity sliding and characterization and the development of analytical flow models. The models may be applicable to other situations such as explosive welding, plate tectonics, and realistic wear models.
Billow clouds due to Kelvin-
Helmholtz instability
[View Extended Abstract]
Symposium D: Materials for Photodevices
D507: InAs/InGaAlAs/InGaAs/InP Quantum Dot Infrared Photodetectors
P. L. Souza, of the Laboratório de Semicondutores, PUC-Rio, Rio de Janeiro, Argentina, described a novel quantum dot structure for infrared photodetectors. Infrared photodetectors based on intraband transitions in quantum dots (QDIPs) should, in principle, outperform the ones based on quantum wells (QWIPs), because of the possibility of absorbing normal incident light and operating at higher temperatures due to the longer electron lifetimes. InAs/InGaAlAs/InGaAs/InP Quantum Dot Infrared Photodetectors were grown by metalorganic vapor phase epitaxy and evaluated. Record values of 0.16 and 0.07 for Δλ/λ for the intraband transitions were obtained at a temperature as high as 120K (for the peaks at 5 and 11 µm shown in the figure) and the latter value represents the smallest for such materials ever reported. The results demonstrate great potential for operation under normal incidence and temperatures above that of liquid nitrogen.
Courtesy: P. L. Souza,
[View Extended Abstract]
D635: New Paradigm For Solar Energy Conversion Using Semiconductor Nanocrystals
Victor I. Klimov, of Los Alamos National Laboratory, USA, discussed the use of nanodots to get two or more excitons (electron-hole pairs) with a single photon of light thereby producing efficiencies that exceed 100%. In fact, the efficiencies can reach 700% in the case of lead selenide nanocrystals. Normally only one exciton is produced per photon, however, carrier multiplication in the nanocrystals allows for more excitons to be produced per photon.
[View Extended Abstract]
D587: TiO2 Nanorods by Decomposition of Ti-Peroxy Compounds
Daniel Stroppa, of the Universidade Federal de São Carlos, presented a poster on Thursday on a simple, low-cost and environmentally clean method to obtain crystalline TiO2 nanorods for use as a photocatalyst in solar energy conversion and for decomposition of toxic organic pollutants. Particle characteristics were studied by varying the fabrication parameters and they were then characterized by XRD and SEM. The results showed that the TiO2 particles were mainly in the form of nanorods with a crystalline phase, and particle size was dependent on the synthesis parameters.
[View Extended Abstract]
Symposium F: Nanostructures and Defect Analysis by Electron Microscopy F554: Use of In Situ TEM to Study Nanomaterials
Barry Carter, of the University of Minnesota, in his presentation on Tuesday described how the development of in situ sample holders and the careful design of  experiments have made the transmission electron microscope a powerful tool for observations of nanoscale properties.
Now, sample holders are able to heat, strain and even compress nanoscale samples, and the improved stability of stages allows for more quantitative information to be obtained. One of the problems, however, is that the new sample holders are expensive and cost on the order of $150,000. Holders are therefore becoming more modular in an attempt to make them more affordable. As an example, Fischione has designed a stage using the filament from a light bulb that takes the temperature to 1500°C.
Carter stated that he believes that studying alumina is still important and his group has examined the distribution of platinum particles on alumina ridges. This effect is very orientation-dependent and the spacing is likely caused by electrostatic charges. Nickel and gold also exhibit similar behavior. The stage also made possible the examination of the role that nickel particles make in the growth of ZnSe nanowires.
 
Courtesy: Barry Carter, Univ. Minnesota
[View Extended Abstract]
F531: Fabrication and Characterization of Nanostructures for Advanced Energy Applications
Grant Norton (Washington State University, USA), in his talk on developing nanostructures for energy applications, described how alternative energy sources are needed for the future with sunlight being an infinite source of energy. He quoted the MRS Bulletin that in turn had quoted from the book “Life of Pi”: “Technology helps and good ideas spread”. The important step now is to incorporate new nanoscale materials into devices and systems that can exploit their unique properties.
Norton's talk was divided into three main areas:
1) The use of silica nanosprings to store molecular hydrogen.
2) The application of ceramic nanowire–metal nanoparticle structures as sensors with applications to fuel cells.
3) Polymer-metal nanocomposites with an absorption spectrum matching solar radiation for ultra-high efficiency solar cells.
His conclusions were that energy is the biggest challenge we face as a society and it requires technological solutions. Nanotechnology can supply many of those solutions and the TEM (transmission electron microscope) is a critical tool in this that can allow us to see what we are making.
[View Extended Abstract]
F552: Atomic Scale Scanning Transmission Electron Microscopy
N. D. Browning, of the University of California-Davis, believes that the key to Scanning Transmission Electron Microscopy is the probe. If the specific location of the problem is known then STEM is the answer. The probe size can be smaller than the column of atoms under investigation. The STEM can be set up to measure both atomic number contrast (Z-contrast or bright-field phase-contrast) as well as analysis (electron energy loss spectroscopy (EELS) or energy dispersive X-ray spectrometry (EDS)) using a small electron probe (typically 0.08-0.2nm in size). With this setup it is possible to investigate such things as interfaces in structural materials, dislocations in semiconductors and nanoparticulate systems for optical or chemical applications. The addition of a monochromator to the STEM improves the performance considerably. An example of the types of measurements that can be made is shown below.
Courtesy: N. Browning, Univ. California, Davis
[View Extended Abstract]
Symposium I: Nanostructured Biological Materials
I622: Nanostructured Materials for the Environmental Control of Cell and Microorganism Growth
Enrico Traversa, of the University of Rome, Italy, described some exciting work on the interactions between materials and biological systems for use in medical and clinical applications. A particular example he investigated was the use of copper nanoparticles to suppress the growth of fungi which can be harmful pathogens for humans. Polymer-matrix nanocomposites with Cu nanoparticles can be used to form packaging that releases copper at a controlled rate that is below the rate that will harm humans but will kill fungi.
[View Extended Abstract]
I616 Biochips: Technologies and Applications
Alberto Pasquarelli, of the University of Ulm,Germany, gave a fascinating talk on the development of bochips. There are five main categories of biochips:
1) DNA Chips, which range from simple glass slides to highly sophisticated devices which can analyze a whole human genome.
2) Protein Microarrays, which allow the simultaneous analysis of hundreds of molecules from samples of tissue or body fluids by means of specific antibodies linked to the chip surface.
3) Patch-clamp Devices, which can be used in automated systems to replace the manual pipetting of cells.
4) Micro Electrode Arrays, which allow the recording of the bioelectric activity of growning multicellular structures, like neuronal networks, or tissue slices.
5) Implants, which can be considered a fall-out of the previous technologies for therapeutic applications and are gaining importance in the areas of functional recovery and its social implications. Cochlear and retinal prosthesis are here the most significant examples.
These biochips can be used to investigate various parts of the cell. Patch clamp devices can even be used to look at the detailed structure of DNA molecules (α-hemplysin) by using the transmembrane potential to force the molecule through a pore and measuring the ionic current blockades that reflect the structure of individual strands.
Statistical analysis of blockade currents allows
the discrimination of different sequences of DNA.
[View Extended Abstract]
Symposium J: 2nd Brazilian Symposium on Microscopy Applied to Forensic Science
J514: Recovering Serial Numbers in Laser Engraved Frames of Firearms
Laser engraving of serial numbers in firearms is currently the norm for new weapons used by the police in Brazil. Stolen firearms often have their serial numbers obliterated. In his talk on Wednesday,
Ladário da Silva (Escola Naval - Marinha do Brasil (EN/MB), Rio de Janeiro, Brazil) described a procedure to recover serial numbers from obliterated laser engraved frames that are usually made of an aluminum alloy. After initial observations, the firearm is cleaned and is then examined under a stereomicroscope. Slow, careful and soft polishing is then used and the surface is scanned periodically. Typically the polishing removes the damage at a rate faster than the components of the serial number. Da Silva presented specific examples of pistols which had the serial numbers laser engraved and which were obliterated in an attempt to eliminate the engraved numbers. In each case, the numbers could be recovered using the method described. The results suggest that in pistols with aluminum alloy frames, with laser engraved serial numbers, the numbers can be successfully revealed with this procedure.
[View Extended Abstract]
Symposium N: Computational Simulation as a Technique to Design New Materials N556: Design of New Porous Materials for Natural Gas Storage
The storage of methane and natural gas is typically achieved using zeolites. Elisa Soares Leite, of the Cidade Universitária, Recife, Brazil, in a theoretical paper, proposed a new porous material called Isoreticular Metal-Organic Frameworks (IRMOFs) which consist of an isoreticular framework with a cubic lattice with tetrahedral Zn4O clusters at the cube vertices and organic dicarboxylate aromatic linkers between the vertices. Each Zn4O is connected to six linkers with an octahedral symmetry. IRMOFs are very versatile materials, since the organic linkers can be easily modified and/or functionalized. Leite simulated storage using Grand Canonical Monte Carlo simulations to calculate the adsorption isotherms of the methane within IRMOF-6. Calculations of this kind allow the investigation of material structures for natural gas and hydrogen storage without the cost of experiments.
Courtesy: Elisa Soares Leite, Cidade Universitária
[View Extended Abstract]
ERRATUM
In the second Meeting Scene e-mail, for the poster presentation in symposium B, (Thermal Resistance of Perovskites with Cerium for Methane Oxidation), we inadvertently included the following "Maria Conceicao Greca, of the Laboratorio de Catalise, Rio de Janeiro, Argentina, ...." Rio de Janeiro is of course in Brazil and not in Argentina. We regret the error.
© Materials Research Society, 2006 |
