1,574 research outputs found
Cancellation of vorticity in steady-state non-isentropic flows of complex fluids
In steady-state non-isentropic flows of perfect fluids there is always
thermodynamic generation of vorticity when the difference between the product
of the temperature with the gradient of the entropy and the gradient of total
enthalpy is different from zero. We note that this property does not hold in
general for complex fluids for which the prominent influence of the material
substructure on the gross motion may cancel the thermodynamic vorticity. We
indicate the explicit condition for this cancellation (topological transition
from vortex sheet to shear flow) for general complex fluids described by
coarse-grained order parameters and extended forms of Ginzburg-Landau energies.
As a prominent sample case we treat first Korteweg's fluid, used commonly as a
model of capillary motion or phase transitions characterized by diffused
interfaces. Then we discuss general complex fluids. We show also that, when the
entropy and the total enthalpy are constant throughout the flow, vorticity may
be generated by the inhomogeneous character of the distribution of material
substructures, and indicate the explicit condition for such a generation. We
discuss also some aspects of unsteady motion and show that in two-dimensional
flows of incompressible perfect complex fluids the vorticity is in general not
conserved, due to a mechanism of transfer of energy between different levels.Comment: 12 page
Comparação de meios de cultivo e métodos de extração na produção de lipídeos por Cryptococcus laurentii.
Comparison between fatty acid composition and oxidative stability of Euterpe oleracea and Euterpe edulis oils.
Peripheric Extended Twists
The properties of the set L of extended jordanian twists are studied. It is
shown that the boundaries of L contain twists whose characteristics differ
considerably from those of internal points. The extension multipliers of these
"peripheric" twists are factorizable. This leads to simplifications in the
twisted algebra relations and helps to find the explicit form for coproducts.
The peripheric twisted algebra U(sl(4)) is obtained to illustrate the
construction. It is shown that the corresponding deformation U_{P}(sl(4))
cannot be connected with the Drinfeld--Jimbo one by a smooth limit procedure.
All the carrier algebras for the extended and the peripheric extended twists
are proved to be Frobenius.Comment: 16 pages, LaTeX 209. Some misprints have been corrected and new
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Spathodea campanulata (Bignoniaceae): flower visitors and nectar characteristics.
Spathodea campanulata is an exotic plant often used in arborisation of Brazilian cities.Its flower resources are toxic for insects, including bees. In order to investigate this westudied a tree located at Embrapa Semiárido (Petrolina) in July-August 2017-2018
Nomenclature for renal replacement therapy and blood purification techniques in critically ill patients: practical applications
This article reports the conclusions of the second part of a consensus expert conference on the nomenclature of renal replacement therapy (RRT) techniques currently utilized to manage acute kidney injury and other organ dysfunction syndromes in critically ill patients. A multidisciplinary approach was taken to achieve harmonization of definitions, components, techniques, and operations of the extracorporeal therapies. The article describes the RRT techniques in detail with the relevant technology, procedures, and phases of treatment and key aspects of volume management/fluid balance in critically ill patients. In addition, the article describes recent developments in other extracorporeal therapies, including therapeutic plasma exchange, multiple organ support therapy, liver support, lung support, and blood purification in sepsis. This is a consensus report on nomenclature harmonization in extracorporeal blood purification therapies, such as hemofiltration, plasma exchange, multiple organ support therapies, and blood purification in sepsis
Quantum Mechanics on the cylinder
A new approach to deformation quantization on the cylinder considered as
phase space is presented. The method is based on the standard Moyal formalism
for R^2 adapted to (S^1 x R) by the Weil--Brezin--Zak transformation. The
results are compared with other solutions of this problem presented by
Kasperkovitz and Peev (Ann. Phys. vol. 230, 21 (1994)0 and by Plebanski and
collaborators (Acta Phys. Pol. vol. B 31}, 561 (2000)). The equivalence of
these three methods is proved.Comment: 21 pages, LaTe
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