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Wyszukujesz frazę "de Oliveira, F." wg kryterium: Autor


Wyświetlanie 1-8 z 8
Tytuł:
The effect of multigrid parameters in a 3D heat diffusion equation
Autorzy:
de Oliveira, F.
Franco, S. R.
Villela Pinto, M. A.
Powiązania:
https://bibliotekanauki.pl/articles/264346.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
metoda różnic skończonych
metoda Gaussa-Seidela
dyfuzja ciepła
multigrid
finite differences
Poisson 3D
solvers
parameters
Opis:
The aim of this paper is to reduce the necessary CPU time to solve the three-dimensional heat diffusion equation using Dirichlet boundary conditions. The finite difference method (FDM) is used to discretize the differential equations with a second-order accuracy central difference scheme (CDS). The algebraic equations systems are solved using the lexicographical and red-black Gauss-Seidel methods, associated with the geometric multigrid method with a correction scheme (CS) and V-cycle. Comparisons are made between two types of restriction: injection and full weighting. The used prolongation process is the trilinear interpolation. This work is concerned with the study of the influence of the smoothing value (v), number of mesh levels (L) and number of unknowns (N) on the CPU time, as well as the analysis of algorithm complexity.
Źródło:
International Journal of Applied Mechanics and Engineering; 2018, 23, 1; 213-221
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tanystropheid archosauromorphs in the Lower Triassic of Gondwana
Autorzy:
De Oliveira, T.M.
Oliveira, D.
Schultz, C.L.
Kerber, L.
Pinheiro, F.L.
Powiązania:
https://bibliotekanauki.pl/articles/23531.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
Tanystropheidae is a clade of early archosauromorphs with a reported distribution ranging from the Early to the Late Triassic of Asia, Europe, and North America. Although some specimens with possible tanystropheid affinities from the Lower Triassic beds of Brazil have been previously attributed to “Protorosauria”, little is known about the tanystropheid record in Gondwana. Here, two new and one previously reported specimen from the Sanga do Cabral Formation (Induan–Olenekian) of Brazil are described and interpreted as ?Tanystropheidae. These records, together with other tetrapods previously reported for the Sanga do Cabral Formation, increase the knowledge of the biotic diversification during the beginning of the Triassic. This contribution reinforces that the archosauromorph diversification occurred shortly after the Permo-Triassic extinction, making the Sanga do Cabral Formation an important unit for the study of early Mesozoic faunas.
Źródło:
Acta Palaeontologica Polonica; 2018, 63, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrospinning of polymeric fibres: an unconventional view on the influence of surface tension on fibre diameter
Elektroprzędzenie włókien polimerowych – niekonwencjonalny pogląd na wpływ naprężenia powierzchniowego na średnice włókien
Autorzy:
Araújo, E. S.
Nascimento, M. L. F.
de Oliveira, H. P.
Powiązania:
https://bibliotekanauki.pl/articles/232610.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
electrospinning
polymeric fibres
Taylor-cone
surfactant
surface tension
elektroprzędzenie
włókna polimerowe
napięcie powierzchniowe
Opis:
The production of regular and bead-free electrospun polymeric fibres requires an adequate combination of different parameters applied in the experimental setup viz. voltage for electrodeposition, viscosity of the solution, density of the polymeric support, the distance between electrodes and the geometry of the spinneret. Determination of the physical balance of forces on the droplet during fibre production was explored and provides relevant theoretical information about the surface tension and radius of polymeric fibres. Based on these predictions, we prepared polymeric electropun fibres of poly (vinyl alcohol), poly (vinyl pyrrolidone) and Eudragit® L100 in order to analyse non-conventional physical properties of experimental systems such as droplet stiffness and their influence on the diameter of resulting fibres.
Produkcja za pomocą elektroprzędzenia regularnych włókien polimerowych, wolnych od zgrubień wymaga dobrania odpowiedniej kombinacji różnych parametrów stanowiska przędącego takich jak np. napięcie między elektrodami, lepkość roztworu przędzalniczego, gęstość, odległość pomiędzy elektrodami i geometria układu przędącego. Badano fizycznie określony balans sił działający na wypychaną kroplę roztworu podczas tworzenia włókna. Badania eksperymentalne dostarczyły odpowiednich teoretycznych informacji o naprężeniu powierzchniowym i średnicy tworzonych włókien polimerowych. W oparciu o uzyskane informacje przygotowano elektroprzędzenie włókien z alkoholu poliwinylowego, alkoholu poliwinylopirolidowego i preparatu Eudragit® L100. Następnie na podstawie wcześniejszych rozważań i uzyskanych wyników eksperymentalnych przeprowadzono analizę wpływu poszczególnych czynników na średnicę otrzymywanych włókien.
Źródło:
Fibres & Textiles in Eastern Europe; 2016, 1 (115); 22-29
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Triton X-100 on PVA Fibres Production by the Electrospinning Technique
Wpływ Triton X-100 na produkcję włókien PVA metodą elektroprzędzenia
Autorzy:
Araújo, E. S.
Nascimento, M. L. F.
de Oliveira, H. P.
Powiązania:
https://bibliotekanauki.pl/articles/233825.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
electrospinning
poly(vinyl alcohol) fibres
surfactant
beads
fibre production
elektroprzędzenia
alkohol poliwinylowy
włókna
środki powierzchniowo czynne
zgrubienia w produkcji włókien
Opis:
Electrospinning represents a low cost technique applied in the production of micro- and nano-fibres. The use of poly(vinyl alcohol) as supporting matrix in aqueous solution for fibre deposition introduces important advantages related with drug release (based on the low toxicity of polymer). On the other side, imperfections of resulting fibres (bead formation) represents an impediment to be circumvented. The introduction of non ionic surfactant (triton X-100) circumvents bead formation and improves the homogeneity of fibre, as verified in the analysis of thermal, structural and morphological properties of PVA net. The results indicate that minimal dispersion of triton X-100 in solution (in the order of 1 wt%) affects the circularity of beads, while at 10 wt% a reduction in the defect concentration in the order of five times is verified with a reasonable reduction in the diameter of the remaining defects and improvement in the regularity of fibres.
Elektroprzędzenie jest techniką o niskich kosztach dla produkcji mikro i nano włókien. Zastosowanie PVA dla odkładania się włókien w wodnym roztworze posiada istotne zalety związane z uwalnianiem się leków i niską toksycznością polimeru. Niedoskonałości otrzymanych włókien w postaci zgrubień skłaniają do poszukiwania środków zaradczych. Badania wykazały, że małe ilości Triton X-100 zdyspergowanego w roztworze w ilości ok. 1% wpływają na zaokrąglenie zgrubień, podczas gdy przy 10% uzyskuje się pięciokrotną redukcję ilości defektów i ich zmniejszenie.
Źródło:
Fibres & Textiles in Eastern Europe; 2013, 4 (100); 39-43
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effectiveness of nanoatrazine in post-emergent control of the tolerant weed Digitaria insularis
Autorzy:
Sousa, B.T.
Pereira, A.E.S.
Fraceto, L.F.
De Oliveira, H.C.
Dalazen, G.
Powiązania:
https://bibliotekanauki.pl/articles/2082785.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
atrazine
chemical control
nanoherbicide
nanotechnology
sourgrass
tolerant
weed control
Opis:
Digitaria insularis (sourgrass) is a monocotyledon weed of difficult control and high in- vasive behavior. Atrazine is widely applied in the Americas to control weeds in maize cul- ture, but its efficiency against D. insularis is limited. The incorporation of atrazine into poly(epsilon-caprolactone) nanocapsules increased the herbicidal activity against suscep- tible weeds; however, the potential of this nanoformulation to control atrazine-tolerant weeds including D. insularis has not yet been tested. Here, we evaluated the post-emergent herbicidal activity of nanoatrazine against D. insularis plants during initial developmental stages. The study was carried out in a greenhouse, using pots filled with clay soil. Plants with two or four expanded leaves were treated with conventional or nanoencapsulated at- razine at 50 or 100% of the recommended dosage (1,000 or 2,000 g ∙ ha −1 ), followed by the evaluation of physiological, growth, and control parameters of the plants. Compared with conventional herbicide, both dosages of nanoatrazine induced greater and faster inhibition of D. insularis photosystem II activity at both developmental stages. Atrazine nanoencap- sulation also improved the control of D. insularis plants, especially in the stage with two expanded leaves. In addition, nanoatrazine led to higher decreases of dry weight of four- leaved plants than atrazine. The use of the half-dosage of nanoatrazine was equally or more efficient in affecting most of the evaluated parameters than the conventional formulation at full dosage. Overall, these results suggest that the nanoencapsulation of atrazine potenti- ated its post-emergent herbicidal activity against D. insularis plants at initial developmental stages, favoring the control of this atrazine-tolerant weed.
Źródło:
Journal of Plant Protection Research; 2020, 60, 2; 185-192
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ergonomic evaluation of workload by milk production - a bibliometric analysis
Autorzy:
Caldas de Oliveira, Claudilaine
Pereira Moro, Antônio Renato
Ulbricht, Leandra
Belinelli, Marjorie
de Souza, Gilberto F.M.
Gabriel, Michele
Zattar, Izabel Cristina
Powiązania:
https://bibliotekanauki.pl/articles/989503.pdf
Data publikacji:
2017
Wydawca:
Instytut Medycyny Wsi
Tematy:
milk production
ergonomics
dairy farming
work environment
bibliometric analysis
Opis:
Introduction and Objective. The purpose of this study was to select in a structured manner the relevant articles with scientific recognition, and simultaneously identify the characteristics of these publications that may scientifically enrich the theme in a portfolio of papers. The theme involves ergonomics in milk production as a criterion for evaluating and improving organizational performance in the milking sector. Materials and Method. The study used ProKnow-C as a theoretical instrument for intervention. Results. The main results show: i) a bibliographic portfolio of 18 items aligned with the view adopted by researchers which served as a theoretical framework for this research; ii) The article entitled “Wrist positions and movements as possible risk factors during machine milking”, by Marianne Stål, Gert-Åke Hansson and Ulrich Moritz in 1999 and published in the Journal of Applied Ergonomics presented the highest scientific recognition, iii) the authors highlighted in the bibliographic portfolio or in its references researching the subject are Gert-Åke Hansson, Marianne Stål and Stefan Pinzke, and iv) the International Journal of Industrial Ergonomics shows the highest number of scientific articles in the bibliographic portfolio. Conclusions. The studies selected using the methodology indicate research in ergonomics focused on the production of milk in rural areas, specifically in the milking sector, are generally related to the health and safety of the workers.
Źródło:
Annals of Agricultural and Environmental Medicine; 2017, 24, 3
1232-1966
Pojawia się w:
Annals of Agricultural and Environmental Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Proposal of heuristic regression method applied in descriptive data analysis: case studies
Autorzy:
Gomes, F. A.
Assis, A. de O.
Reis, M. R. da C.
Gomes, V. M.
Oliveira, S. G. M.
Araujo, W. R. H. de
Calixto, W. P.
Powiązania:
https://bibliotekanauki.pl/articles/136229.pdf
Data publikacji:
2017
Wydawca:
EEEIC International Barbara Leonowicz Szabłowska
Tematy:
regression
data analysis
optimization
heuristic
modeling
Opis:
The purpose of this paper is to use the hybridized optimization method in order to find mathematical structures for analysis of experimental data. The heuristic optimization method will be hybridized with deterministic optimization method in order to that structures found require not knowledge about data generated experimentally. Five case studies are proposed and discussed to validate the results. The proposed method has viable solution for the analysis of experimental data and extrapolation, with mathematical expression reduced.
Źródło:
Transactions on Environment and Electrical Engineering; 2017, 2, 2; 51-57
2450-5730
Pojawia się w:
Transactions on Environment and Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Facies architecture of the fluvial Missão Velha Formation (Late Jurassic-Early Cretaceous), Araripe Basin, Northeast Brazil : paleogeographic and tectonic implications
Autorzy:
Fambrini, G. L.
Neumann, V. H. M. L.
Menezes-Filho, J. A. B
da Silva-Filho, W. F.
de Oliveira, É. V.
Powiązania:
https://bibliotekanauki.pl/articles/139001.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Araripe Basin
Missão Velha Formation
fluvial facies
architectural element
rift basins
basen Araripe
Missão Velha
facje rzeczne
element architektoniczny
rów tektoniczny
Opis:
Sedimentological analysis of the Missão Velha Formation (Araripe Basin, northeast Brazil) is the aim of this paper through detailed facies analysis, architectural elements, depositional systems and paleocurrent data. The main facies recognized were: (i) coarse-grained conglomeratic sandstones, locally pebbly conglomerates, with abundant silicified fossil trunks and several large-to-medium trough cross-stratifications and predominantly lenticular geometry; (ii) lenticular coarse-to-medium sandstones with some granules, abundant silicified fossil wood, and large-to-medium trough cross-stratifications, cut-and fill features and mud drapes on the foresets of cross-strata, (iii) poorly sorted medium-grained sandstones with sparse pebbles and with horizontal stratification, (iv) fine to very fine silty sandstones, laminated, interlayered with (v) decimetric muddy layers with horizontal lamination and climbing-ripple cross-lamination. Nine architectural elements were recognized: CH: Channels, GB: Gravel bars and bed forms, SB: Sand bars and bedforms, SB (p): sand bedform with planar cross-stratification, OF: Overbank flow, DA: Downstream-accretion macroforms, LS: Laminated sandsheet, LA: Lateral-accretion macroforms and FF: Floodplain fines. The lithofacies types and facies associations were interpreted as having been generated by alluvial systems characterized by (i) high energy perennial braided river systems and (ii) ephemeral river systems. Aeolian sand dunes and sand sheets generated by the reworking of braided alluvial deposits can also occur. The paleocurrent measurements show a main dispersion pattern to S, SE and SW, and another to NE/E. These features imply a paleodrainage flowing into the basins of the Recôncavo-Tucano-Jatobá.
Źródło:
Acta Geologica Polonica; 2017, 67, 4; 515-545
0001-5709
Pojawia się w:
Acta Geologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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