1,612 research outputs found
O conceito de literatura de viagens no bojo de algumas narraçoesiies científicas sobre Moçambique constituintes do iluminismo portugues (1758 - 1807)
Ao longo de e por todo o Impérío Ultramarino Portugues, como parte da política colonial do
Marques de Pombal (1750 a 1777, contando os períodos como Ministro dos Negócios
Estrangeiros e Prímeiro-Ministro), surge a necessidade de se obter um maior conhecimento sobre
o que se passava pelas diversas colonias, exigíndo deste modo, constantes relatórios sobre os
recursos naturais, a situayao política, economico-fmanceira e admmistrativa de tais territorios
Coronal mass ejections observed by heliospheric imagers at 0.2 and 1 au: the events on April 1 and 2, 2019
Context. We study two coronal mass ejections (CMEs) observed between April
1-2, 2019 by both the inner Wide-Field Imager for Parker Solar Probe (WISPR-I)
and the inner heliospheric imager (HI-1) on board STEREO-A. This is the first
study of CME observations from two viewpoints in similar directions but at
considerably different solar distances. Aims. Our objective is to understand
how the PSP observations affect the CME kinematics, especially due to its
proximity to the Sun. Methods. We estimate the CME positions, speeds,
accelerations, propagation directions and longitudinal deflections using
imaging observations from two spacecraft, and a set of analytical expressions
that consider the CME as a point structure and take into account the rapid
change in spacecraft position. Results. We find that both CMEs are slow (), propagating eastward of the Sun-Earth line. The second CME
seems to accelerate between to and deflect westward
with an angular speed consistent with the solar rotation speed. We find some
discrepancies in the CME solar distance (up to , particularly for CME
\#1), latitude (up to ) and longitude (up to ) when
comparing results from different fit cases (different observations or set of
free parameters). Conclusions. Discrepancies in longitude are likely due to the
feature tracked visually rather than instrumental biases or fit assumptions.
For similar reasons, the CME \#1 solar distance, as derived from WISPR-I
observations, is larger than the HI-1 result, regardless of the fit parameters
considered. Error estimates for CME kinematics do not show any clear trend
associated to the observing instrument. The source region location and the lack
of any clear in situ counterparts (both at near-Earth and at PSP) support our
estimate of the propagation direction for both events.Comment: 27 pages, 10 figures. Submitted for publication on Astronomy and
Astrophysic
Tensile behavior of an eutectic Pb–Sn alloy processed by ECAP and rolling
AbstractA eutectic lead–tin alloy was prepared by melting the commercially pure metals and cast in cylindrical molds with 10mm diameter. The billets were processed by 4 passes of ECAP using a die with 90° between channels through route A and rolled to a final thickness of ∼1mm. The microstructure was determined by optical microscopy. Tensile tests were carried out at room temperature in the strain rate range between 10−4 and 10−2s−1. The results show the elongation to failure increases at low strain-rates. The strain-rate sensitivity parameter was determined and a maximum value of ∼0.4 was observed at the lowest strain-rate
Alternatives in polymerization contraction stress management
Polymerization contraction stress of dental composites is often associated with marginal and interfacial failure of bonded restorations. The magnitude of the stress depends on the composite's composition (filler content and matrix composition) and its ability to flow before gelation, which is related to the cavity configuration and curing characteristics of the composite. This article reviews the variations found among studies regarding the contraction stress testing method, contraction stress values of current composites, and discusses the validity of contraction stress studies in relation to results from microleakage tests. The effect of lower curing rates and alternative curing routines on contraction stress values is also discussed, as well as the use of low elastic modulus liners. Moreover, studies with experimental Bis-GMA-based composites and recent developments in low-shrinkage monomers are described
Mapping Co-Cr-Cu and Fe Occurrence in a Legacy Mining Waste Using Geochemistry and Satellite Imagery Analyses
Abandoned mining wastes are both an environmental challenge and a possible secondary
raw material source. The characterization and monitoring of these sites are often expensive and
cumbersome because of the need of repeated field surveys. Remote sensing data are a cost-effective
alternative that helps in producing multiscale maps of mining wastes. These maps can be used to
investigate and monitor the spatial patterns of different elements within the mining wastes. In this
work, Sentinel-2 images are combined with the geochemical samples in order to map the distribution
of iron, copper, chromium, and cobalt. The target area was the Vigonzano mining wastes in Northern
Apennines (Italy) where there are a small number of geochemical analyses but a large amount of
satellite image data. We used the multivariate geostatistical estimation method (Co-Kriging) that
exploit the meaningful spatial correlation between the elements of interest and band ratios (obtained
from Sentinel-2 images). The concentration maps highlighted subareas for Cu and Cr with an
estimated grade of about 0.3% and 0.2%, respectively. In addition, the critical element Co showed
an enrichment in the south-east part of the mining wastes, in a similar pattern as Cr. Instead, the
obtained maps show Ce, La, Rb, and Nb depletion compared to the surrounding agricultural areas.
The concentration maps were intended as a prefeasibility study to determine enriched areas for
further detailed investigation
Avaliação da sustentabilidade da expansão do perímetro urbano da cidade de Piracicaba - SP por meio de indicadores de forma urbana
Este artigo tem como objetivo a discussão e o desenvolvimento de indicadores para avaliação da sustentabilidade de processos de expansão urbana com base no conceito de forma urbana sustentável. O conceito de forma urbana sustentável reconhece que cidades mais compactas, socioespacialmente diversas e com usos do solo integrados são mais sustentáveis tanto ambiental quanto socialmente. O estudo de caso é a cidade de Piracicaba-SP e são avaliados os perímetros urbanos delimitados nos anos de 2000 e 2013. Foram desenvolvidos e aplicados seis indicadores. Os resultados indicaram que a delimitação do perímetro urbano não atendeu aos padrões de sustentabilidade, bem como houve uma piora dos indicadores no período analisado
TRANSPARÊNCIA E CONTROLE SOCIAL NAS NORMAS SOBRE ESTUDO DE IMPACTO DE VIZINHANÇA NA AGLOMERAÇÃO URBANA DE PIRACICABA-SP.
O Estudo de Impacto de Vizinhança - EIV - visa mediar os conflitos de vizinhança advindos da implantação de empreendimentos com potencial de gerar significativo incômodo ou impacto urbanístico sua vizinhança. Trata-se se um importante avanço introduzido pelo Estatuto da Cidade tanto como instrumento de controle do uso e ocupação do solo, quanto de democratização da gestão urbana local. O EIV, para cumprir as funções previstas no Estatuto da Cidade, deve ter ampla publicidade, ser submetido a audiência pública e ser apreciado por conselho local de política pública. O presente trabalho avalia os Planos Diretores, e normas urbanísticas correlatas, dos 23 municípios da Aglomeração Urbana de Piracicaba-SP, quanto aos aspectos relativos à transparência e o controle social no processo de análise e aprovação dos Estudos de Impacto de Vizinhança. Os resultados apontaram que nenhum dos municípios analisados adota procedimentos que atendam os requisitos básicos de transparência pública e de controle social, como previstos na Lei de Acesso á Informação e o Estatuto da Cidade
RAÍZES DA QUESTÃO REGIONAL NO ESTADO DE SÃO PAULO: CONSIDERAÇÕES SOBRE O VALE DO RIBEIRA
This text discusses on the problem of the regional disparities in the São Paulo State and analyses the causes of the economic stagnation of the region of the Ribeira Valley. It’s made a historical profile of the regional economic formation in São Paulo State, since the century XVI to middles of the present century, through the cycles of gold, of naval construction, of rice and of banana. The placed arguments answer the explanations based on the thesis of the regional imperialism. The conclusion is that the decadence and stagnation of the area was due to a conjugation of historical and geographical factors, such as the end of the slavery, the geographical isolation, the regional lack of aptitude for the coffee cultivation and the difficulty of settling of free labour (immigrants) in the area.
Key-words: Regional Development, Underdevelopment, Ribeira ValleyEste texto discute o problema das disparidades regionais no Estado de São Paulo e analisa as causas da estagnação econômica da região do Vale do Ribeira. É feito um perfil histórico da formação econômica regional no contexto paulista, desde o século XVI até meados do presente século, passando pelos ciclos do ouro, da construção naval, da rizicultura e da bananicultura. Os argumentos colocados contestam as explicações baseadas na tese do imperialismo regional. Conclui-se que a decadência e estagnação da região deveu-se a uma conjugação de fatores históricos e geográficos, entre os quais o fim do complexo rural escravista, o isolamento geográfico, a inaptidão regional para a cafeicultura e a dificuldade de fixação da mão-de-obra livre (imigrantes) na região.
Palavras-chave: Desenvolvimento Regional, Subdesenvolvimento, Vale do Ribeir
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