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Search Results: 1 - 10 of 744674 matches for " M. V. da S.;Silva "
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Estudo da intercala??o de compostos organicos em caulins na forma ácida
Fernandes, M. V. da S.;Silva, L. R. D. da;
Ceramica , 2011, DOI: 10.1590/S0366-69132011000200014
Abstract: the feasibility of using major clays such as kaolin in the adsorption processes, can occur through chemical modification by intercalation in their structures phyllite. samples of kaolin in the region of northeast brazil, one white and one gray of a portion of the region borborema-served in the state of paraiba, were interspersed with dimethylsulfoxide, oxalic acid and citric acid. the characterization natural and modified techniques were used x-ray diffraction, thermal analysis and absorption spectroscopy in the infrared.
Isolation of lignans glycosides from Alibertia sessilis (Vell.) K. Schum. (Rubiaceae) by preparative high-performance liquid chromatography
Silva, V. C. da;Silva, G. H.;Bolzani, V. da S.;Lopes, M. N.;
Eclética Química , 2006, DOI: 10.1590/S0100-46702006000400008
Abstract: enantiomeric aglycone lignans contained in a mixture were separated from a fraction of the extract of the stems of alibertia sessilis (vell.) k. schum. (rubiaceae) by preparative high-performance liquid chromatography. an efficient and fast separation can be achieved with methanol-water (30:70, v/v). their structures were identified as (+)-lyoniresinol 3a-o-b-glucopyranoside and (-)-lyoniresinol 3a-o-b-glucopyranoside, being reported for the first time in rubiaceae.
Modifica??es na matriz de um Argissolo Amarelo Coeso sob diferentes sistemas de manejo com cana-de-a?úcar
Silva, Apolino J. N. da;Cabeda, Mário S. V.;
Revista Brasileira de Engenharia Agrícola e Ambiental , 2006, DOI: 10.1590/S1415-43662006000300004
Abstract: the management systems with sugarcane in soils of coastal tablelands can cause important alterations in the soil matrix. the effects of different management systems with sugar cane in the organization of the matrix of a cohesive yellow argisol, in the triunfo sugar cane mill in state of alagoas, as compared to a virgin soil were studied. the management systems consisted of irrigated area, not irrigated, with vinasse application and an area under native forest as original condition. samples were collected from each site at 0-0.2, 0.2-0.4 and 0.4-0.8 m depths to determine the alterations in the soil structure, in pore system and in the arrangement of particles of the soils cultivated with sugarcane, in relation to the soil under native forest. the cultivated soils presented an association of natural porosity with planar pores resultant of the cultivation and a more compact arrangement of particles in the soil matrix. in the aggregates of the cultivated soils a massive aspect and orientation of clay particle was verified in relation to the aggregates of the soil under native forest.
Análise do efeito de diferentes intensidades e intervalos de recupera??o na percep??o subjetiva de atletas
Silva,M.S.; Silva,T.S.; Mota,M.R.; Damasceno,V.O.; Silva,F. Martins da;
Motricidade , 2011,
Abstract: the research examined the effects of different intensities and different rest intervals of strength training on the rating of perceived exertion (rpe) in young athletes. participated in the study 23 young men, aged 17.06 ± .73 years, 68.01 ± 8.09 kg of body mass, and 173.65 ± 5.61 cm of height. they were submitted to the appropriateness of charges (5 rm, 10 rm or 15 rm) and rest intervals (30, 60 or 120 s) and then asked to point perceived exertion according to the omni-res scale. a two-way anova was used and significant differences were analyzed by post-hoc bonferroni. for rpe there were no significant differences between the intensities in the recovery intervals evaluated. for intervals with the same intensity, there were differences between 15 rm and range of 120 and 60 s with 15 rm and 30 s intervals. intensities of 10 and 5 rm, in the range of 120 s showed significant differences. it follows that the smaller the rest interval the greater the levels of fatigue regardless of the number of repetitions performed in all intensities and it may be inferred that the rpe was sensitive to reduction in the rest interval.
Four Fermion Field Theories and the Chern-Simons Field: A Renormalization Group Study
V. S. Alves,M. Gomes,S. V. L. Pinheiro,A. J. da Silva
Physics , 1999, DOI: 10.1103/PhysRevD.60.027701
Abstract: In (2+1) dimensions, we consider the model of a $N$ flavor, two-component fermionic field interacting through a Chern-Simons field besides a four fermion self-interaction which consists of a linear combination of the Gross-Neveu and Thirring like terms. The four fermion interaction is not perturbatively renormalizable and the model is taken as an effective field theory in the region of low momenta. Using Zimmerman procedure for reducing coupling constants, it is verified that, for small values of the Chern-Simons parameter, the origin is an infrared stable fixed point but changes to ultraviolet stable as $\alpha$ becomes bigger than a critical $\alpha_c$. Composite operators are also analyzed and it is shown that a specific four fermion interaction has an improved ultraviolet behavior as $N$ increases.
The Perturbative Gross Neveu Model Coupled to a Chern-Simons Field: A Renormalization Group Study
V. S. Alves,M. Gomes,S. V. L. Pinheiro,A. J. da Silva
Physics , 1998, DOI: 10.1103/PhysRevD.59.045002
Abstract: In 2+1 dimensions, for low momenta, using dimensional renormalization we study the effect of a Chern-Simons field on the perturbative expansion of fermions self interacting through a Gross Neveu coupling. For the case of just one fermion field, we verify that the dimension of operators of canonical dimension lower than three decreases as a function of the Chern-Simons coupling.
A Renormalization Group Study of the $(φ^* φ)^3$ Model coupled to a Chern-Simons Field
V. S. Alves,M. Gomes,S. L. V. Pinheiro,A. J. da Silva
Physics , 2000, DOI: 10.1103/PhysRevD.61.065003
Abstract: We consider the model of a massless charged scalar field, in (2+1) dimensions, with a self interaction of the form $lambda (\phi^* \phi)^3$ and interacting with a Chern Simons field. We calculate the renormalization group $\beta$ functions of the coupling constants and the anomalous dimensions $\gamma$ of the basic fields. We show that the interaction with the Chern Simons field implies in a $\beta_{\lambda}$ which suggests that a dynamical symmetry breakdown occurs. We also study the effect of the Chern Simons field on the anomalous dimensions of the composite operators $(\phi^* \phi)^n$, getting the result that their operator dimensions are lowered.
Complexity and predictability of daily precipitation in a semi-arid region: an application to Ceará, Brazil
M. E. S. Silva, L. M. V. Carvalho, M. A. F. da Silva Dias,T. de M. B. S. Xavier
Nonlinear Processes in Geophysics (NPG) , 2006,
Abstract: Complexity and predictability of daily precipitation in a tropical semi-arid region (Ceará State, Brazil) is assessed by applying entropy concepts. Precipitation regimes in that region depend on several dynamical forcings, the most important being the displacement and activity of the Inter-tropical Convergence Zone in the Atlantic Ocean. Topography is another important factor that influences the spatial distribution of rainfall in the region. A hierarchical approach based on sequences of events of different lengths is used to estimate complexity of daily precipitation records. It is shown that precipitation in Ceará exhibit more random than periodic sequences, which indicates a large degree of complexity. Nevertheless, there is indication of potentially inherent rules in the precipitation time-series that could ultimately improve prediction on time-scales between 9–11 days. It is suggested that synoptic-scale disturbances (1–8 days) represent important sources of rules in the precipitation regimes in this region.
Síntese de 5-nitro-isatina e 5-cloro-isatina a partir da isonitrosoacetanilida
Silva, Bianca N. M. da;Bastos, Renato S.;Silva, Bárbara V.;Pinto, Angelo C.;
Química Nova , 2010, DOI: 10.1590/S0100-40422010001000043
Abstract: this article describes the preparation of 5-nitroisatin and of 5-chloroisatin from isonitrosoacetanilide in a single step, using readily available and inexpensive reagents. these reactions require around 90 minutes and may be carried out as an undergraduate experiment, providing an opportunity to discuss the electrophilic aromatic substitution mechanism, as well as spectroscopic techniques for product identification.
Reciclagem de escória cristalizada para a produ??o de argamassa
Ribeiro, V.A.S.;da Silva, A.L.;da Silva, M.R.;Dias, J.C.;
Matéria (Rio de Janeiro) , 2007, DOI: 10.1590/S1517-70762007000200012
Abstract: all discarded residues of the steelmaking industries and the cut of ornamental stone constitute a serious problem, once they occupy large ground areas that in turn become economically inactive. usually, the solutions found out by the companies to discard such residues are the sanitary landfill and municipal solid wastes; however, in the structure of great cities, there are no spaces for this kind of disposal due to agglomeration of peoples in the urban centers and the high valuation of ground lots in some areas. these residues are found in great volume in the center-western region of minas gerais state and they don?t find adequate final destination. the waste question is also relevant, once the discarding of industrial residues results in loss of goods that could be otherwise recycled and, by this way, generate other production goods. in this context, the present work aims at to contribute for the recycling of the residues generated in the referred region in order to prepare mortar for civil construction. the thermal behavior of the slag/granite and slag/slate composites was experimentally analyzed with the objective to find some application of these materials in the ground of civil engineering. with these thermal behavior results, an investigation was carried out of the viability of substituting the slag/granite composites for the hydrated lime, through the assays of water retention in the cool state and of the axial and of axial compressive strength in the hardened state with the objective to contribute for a new use of the new use of the residue.
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