Controlled route to the fabrication of carbon and boron nitride nanoscrolls: A molecular dynamics investigation

Carbon nanoscrolls (graphene layers rolled up into papyrus-like tubular structures) are nanostructures with unique and interesting characteristics that could be exploited to build several new nanodevices. However, an efficient and controlled synthesis of these structures was not achieved yet, making its large scale production a challenge to materials scientists. Also, the formation process and detailed mechanisms that occur during its synthesis are not completely known. In this work, using fully atomistic molecular dynamics simulations, we discuss a possible route to nanoscrolls made from graphene layers deposited over silicon oxide substrates containing chambers/pits. The scrolling mechanism is triggered by carbon nanotubes deposited on the layers. The process is completely general and can be used to produce scrolls from other lamellar materials, like boron nitride, for instance. © 2013 American Institute of Physics.

Search for supersymmetry in events with photons and low missing transverse energy in pp collisions at √s=7TeV

Many models of new physics, including versions of supersymmetry (SUSY), predict production of events with low missing transverse energy, electroweak gauge bosons, and many energetic final-state particles. The stealth SUSY model yields this signature while conserving R-parity by means of a new hidden sector in which SUSY is approximately conserved. The results of a general search for new physics, with no requirement on missing transverse energy, in events with two photons and four or more hadronic jets are reported. The study is based on a sample of proton-proton collisions at s=7TeV corresponding to 4.96fb-1 of integrated luminosity collected with the CMS detector in 2011. Based on good agreement between the data and the standard model expectation, the data are used to determine model-independent cross-section limits and a limit on the squark mass in the framework of stealth SUSY. With this first study of its kind, squark masses less than 1430 GeV are excluded at the 95% confidence level. © 2012 CERN.

Poverty and low income measurement in Canada: recent analyses and future directions

Includes bibliography

Estudo do efeito springback em aços avançados de alta resistência aplicados a indústria automobilística

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Macauba palm (acrocomia aculeata) cake from biodiesel processing: an efficient and low cost substrate for the adsorption of dyes

The potential of natural and heat-treated Macauba palm cake as adsorbent for the removal of Methylene Blue (MB) and Congo Red (CR) from solution has been investigated. Equilibrium adsorption was attained in <7 h and the process was favored at pH 5.0 for MB and pH 6.5 for CR with an adsorbent (g):adsorbate (mL) ratio of 1:200 and an initial concentration of adsorbate of 25 mg L−1. The maximum adsorption capacities of the natural and heat-treated materials were, respectively, 25.80 and 32.30 mg g−1 for MB, and 32.00 and 20.30 mg g−1 for CR. The isotherm model proposed by Sips represented most adequately the adsorption of MB and CR. The adsorptions of the dyes were best described in terms of a pseudo second-order reaction. Thermodynamic parameters such as ΔHo, ΔSo and ΔGo were calculated. The adsorption process was found to be endothermic and spontaneous. Macauba palm cake is adequate for the removal of waste dye from industrial effluents by virtue of its abundance, low cost and efficiency of adsorption.

Carbon and oxygen isotope geochemistry of Ediacaran outer platform carbonates, Paraguay Belt, central Brazil

Após a glaciação do final do Criogeniano, a região central do Brasil foi palco de extensa deposição de carbonatos plataformais do Grupo Araras. Este grupo inclui na sua base uma seqüência de capa carbonática sucedida por depósitos transgressivos de calcilutitos betuminosos e folhelhos de plataforma profunda. Dados de fácies e estratigráficos combinados com análises isotópicas de carbono e oxigênio da seção mais completa desses depósitos transgressivos, expostos no sinclinal da Guia, foram empregados para avaliar o paleambiente deposicional e para testar a correlação desses depósitos ao longo da faixa e também com outras unidades de outros continentes. A sucessão estudada consiste de 150 m de espessura de camadas tabulares de calcilutitos e folhelhos cinza a pretos com valores de d13CPDB negativos, entre -2,5 e -1 . O perfil de d13CPDB do sinclinal da Guia mostra clara correlação com a porção superior da Formação Guia da região de Cáceres, 200 km a sudoeste. O perfil de d13CPDB do Grupo Araras é comparável aos perfis de d13CPDB de outras unidades ediacaranas da parte sul da Faixa Paraguai, oeste do Canadá, e crátons do Congo e do Kalahari. Além disso, a distribuição de fácies, estratigrafia e o perfil isotópico do Grupo Araras são equiparáveis à porção média do Subgrupo Tsumeb na Namíbia, o que reforça a atribuição de idade Ediacarana para o Grupo Araras.

Microwave switchable frequency selective surface with high quality factor resonance and low polarization sensitivity

We present a microwave switchable frequency selective surface with high quality factor transmission resonance. The high quality resonance is achieved by excitation of the trapped-mode in array with two concentric metal rings in a cell on a silicon substrate. Optical activation of the silicon substrate permits to switch off the transmission band.

Avaliação da tenacidade à fratura na região de transição dúctil-frágil dos aços API 5L X70 e X80 utilizando a metodologia da curva mestra

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Diagnostics of equatorial and low latitude ionosphere by TEC mapping over Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Performance evaluation of multi-stage filtration with use of granular activated carbon and synthetic non-woven fabrics

The multi stage filtration (MSF) is an alternative that permits to enlarge the spectrum of application of the slow sand filtration as for the effluent quality and run duration. In this research the use of MSF technology associated to a granular activated carbon (GAC) column as polishing mechanism of the final effluent was evaluated; in the slow sand filters GAC was used as an intermediate layer and non-woven synthetic fabrics were utilized as a first layer of the filter media. Five different tests were conducted, where the systems subjected to the treatment were: water from the Ipe Lake (Ilha Solteira, Sao Paulo, Brazil); water from the lake with water from a recreational fish pond; water from the lake with a phytoplankton and cyanobacteria overload simulation, with and without the use of the pre-filters as a stage of the treatment. The synthetic fabrics and GAC use resulted in the best turbidity removal and an efficient apparent and true color removal; in spite that the polishing columns reported similar results for those parameters. The utilization of GAC as an intermediate layer contributed to a better organic matter removal and the fabrics improved chlorophyll-a removal. The pre-filtration columns made an efficient algae and cyanobacteria removal, a function that was completed by the filters and reached >98% efficiency. The synthetic non-woven fabrics and GAC inclusion in MSF operation improved performance of this technology with ease of application and operation.

Distribution of fluoride and calcium in plaque biofilms after the use of conventional and low-fluoride dentifrices

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Plaque fluoride concentrations associated to the use of conventional and low-fluoride dentifrices

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Streptococcus Mutans Photoinactivation by Combination of Short Exposure of a Broad-Spectrum Visible Light and Low Concentrations of Photosensitizers

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Healing of normal and osteopenic bone with titanium implant and low-level laser therapy (GaAlAs): a histomorphometric study in rats

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)