4,598 research outputs found
Microfluidic-SANS: flow processing of complex fluids
Understanding and engineering the flow-response of complex and non-Newtonian fluids at a molecular level is a key challenge for their practical utilisation. Here we demonstrate the coupling of microfluidics with small angle neutron scattering (SANS). Microdevices with high neutron transmission (up to 98%), low scattering background ([Image: see text]), broad solvent compatibility and high pressure tolerance (≈3–15 bar) are rapidly prototyped via frontal photo polymerisation. Scattering from single microchannels of widths down to 60 μm, with beam footprint of 500 μm diameter, was successfully obtained in the scattering vector range 0.01–0.3 Å(−1), corresponding to real space dimensions of [Image: see text]. We demonstrate our approach by investigating the molecular re-orientation and alignment underpinning the flow response of two model complex fluids, namely cetyl trimethylammonium chloride/pentanol/D(2)O and sodium lauryl sulfate/octanol/brine lamellar systems. Finally, we assess the applicability and outlook of microfluidic-SANS for high-throughput and flow processing studies, with emphasis of soft matter
CONTROLE E DISPUTA PELA DEMOCRACIA NA COMUNICAÇÃO SOCIAL
This article analyzes the current state of the Brazilian media in relation to the influence of the companies that constitute Mass Communication Enterprises in Brazil . On the other hand, observes the participation of the movements for democratizing the media. The paper looks to contribute for the theoretical debate and of perspectives for a better performance on the part of the activists of communitarian communication, as well as the popular movement. The article goes through a bibliographical and documental research, besides the analysis of recent data, looking to evidence the importance of the constitution of democratic public politics for the people empowerment in our country
First detection of CF+ towards a high-mass protostar
We report the first detection of the J = 1 - 0 (102.6 GHz) rotational lines
of CF+ (fluoromethylidynium ion) towards CygX-N63, a young and massive
protostar of the Cygnus X region. This detection occurred as part of an
unbiased spectral survey of this object in the 0.8-3 mm range, performed with
the IRAM 30m telescope. The data were analyzed using a local thermodynamical
equilibrium model (LTE model) and a population diagram in order to derive the
column density. The line velocity (-4 km s-1) and line width (1.6 km s-1)
indicate an origin from the collapsing envelope of the protostar.
We obtain a CF+ column density of 4.10e11 cm-2. The CF+ ion is thought to be
a good tracer for C+ and assuming a ratio of 10e-6 for CF+/C+, we derive a
total number of C+ of 1.2x10e53 within the beam. There is no evidence of carbon
ionization caused by an exterior source of UV photons suggesting that the
protostar itself is the source of ionization. Ionization from the protostellar
photosphere is not efficient enough. In contrast, X-ray ionization from the
accretion shock(s) and UV ionization from outflow shocks could provide a large
enough ionizing power to explain our CF+ detection.
Surprisingly, CF+ has been detected towards a cold, massive protostar with no
sign of an external photon dissociation region (PDR), which means that the only
possibility is the existence of a significant inner source of C+. This is an
important result that opens interesting perspectives to study the early
development of ionized regions and to approach the issue of the evolution of
the inner regions of collapsing envelopes of massive protostars. The existence
of high energy radiations early in the evolution of massive protostars also has
important implications for chemical evolution of dense collapsing gas and could
trigger peculiar chemistry and early formation of a hot core.Comment: 6 page
On the nature of the spin-polarized hole states in a quasi-two-dimensional GaMnAs ferromagnetic layer
A self-consistent calculation of the density of states and the spectral
density function is performed in a two-dimensional spin-polarized hole system
based on a multiple-scattering approximation. Using parameters corresponding to
GaMnAs thin layers, a wide range of Mn concentrations and hole densities have
been explored to understand the nature, localized or extended, of the
spin-polarized holes at the Fermi level for several values of the average
magnetization of the Mn ystem. We show that, for a certain interval of Mn and
hole densities, an increase on the magnetic order of the Mn ions come together
with a change of the nature of the states at the Fermi level. This fact
provides a delocalization of spin-polarized extended states anti-aligned to the
average Mn magnetization, and a higher spin-polarization of the hole gas. These
results are consistent with the occurrence of ferromagnetism with relatively
high transition temperatures observed in some thin film samples and
multilayered structures of this material.Comment: 3 page
Variedades de abacaxi.
Todas as variedades de abacaxi cujo interesse é o fruto, seja para consumo in natura ou para processamento, pertencem à espécie Ananas comosus var. comosus. Alguns clones de Ananas comosus var. erectifolius, Ananas comosus var. ananassoides e Ananas comosus var. bracteatus são cultivados para produção de fibra ou para fins ornamentais. Recentemente, houve grande incremento nestas formas de utilização. A variedade de abacaxi predominantemente cultivada no mundo é a Smooth Cayenne, responsável por cerca de 70% da produção mundial de abacaxi. Contudo, outras variedades como Singapore Spanish, Queen, Red Spanish, Pérola e Perolera são muito cultivadas e difundidas em nÃvel mundial (Leal, 1990). No Brasil, onde a área de plantio em 2002 foi de 62.597 ha, com produção de 1.430.018 mil frutos e rendimento de 22.845 frutos/ha (IBGE, 2003), a variedade mais plantada é a Pérola, responsável por cerca de 80% da produção brasileira de abacaxi havaiano, cujos plantios se concentram no Sudeste do paÃs, principalmente em São Paulo e na região do Triângulo Mineiro.bitstream/item/81569/1/Circular-Tecnica-63-Variedade-Abacaxi-Renato-Cabral-2003.pdfMemória
Internamentos Compulsivos: revisão da casuÃstica dos HUC e HIP no triénio 2006-2008.
ão obstante terem passado mais de 10 anos sobre a publicação da Lei de Saúde Mental, o intenso debate
e reflexão ocorridos não foram acompanhados por publicação, igualmente profusa, de investigação clÃnica
sobre a epidemiologia dos internamentos compulsivos. Os autores procuraram caracterizar o arquétipo do
doente submetido a internamento involuntário em Portugal, apreciando variáveis demográficas, clÃnicas e legais.
Para esse fim, conduziu-se um estudo retrospectivo dos internamentos compulsivos ocorridos entre 2006
e 2008 em dois hospitais: os Hospitais da Universidade de Coimbra (HUC) e o Hospital Infante D. Pedro –
Aveiro (HIP). Uma amostra de 384 internamentos foi recolhida e caracterizada, apresentando-se resultados
desta investigação e discussão dos dados obtidos
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