8,097 research outputs found
Qualidade de biscoitos formulados com diferentes teores de farinha de casca de pequi.
O objetivo deste estudo foi avaliar a qualidade de biscoitos tipo cookie, formulados com diferentes níveis de farinha de casca de pequi (FCP), em substituição à farinha de trigo (FT). Utilizou-se um delineamento inteiramente casualizado, com controle mais quatro tratamentos (12,5%; 25%; 37,5%; e 50% de substituição de FT por FCP), e quatro repetições. Foram analisados: aceitabilidade, cor (luminosidade), composição centesimal, valor energético e teores de alguns minerais de cada amostra
Simulation of Flow of Mixtures Through Anisotropic Porous Media using a Lattice Boltzmann Model
We propose a description for transient penetration simulations of miscible
and immiscible fluid mixtures into anisotropic porous media, using the lattice
Boltzmann (LB) method. Our model incorporates hydrodynamic flow, diffusion,
surface tension, and the possibility for global and local viscosity variations
to consider various types of hardening fluids. The miscible mixture consists of
two fluids, one governed by the hydrodynamic equations and one by diffusion
equations. We validate our model on standard problems like Poiseuille flow, the
collision of a drop with an impermeable, hydrophobic interface and the
deformation of the fluid due to surface tension forces. To demonstrate the
applicability to complex geometries, we simulate the invasion process of
mixtures into wood spruce samples.Comment: Submitted to EPJ
Correlation functions in the two-dimensional random-field Ising model
Transfer-matrix methods are used to study the probability distributions of
spin-spin correlation functions in the two-dimensional random-field Ising
model, on long strips of width sites, for binary field
distributions at generic distance , temperature and field intensity
. For moderately high , and of the order of magnitude used in
most experiments, the distributions are singly-peaked, though rather
asymmetric. For low temperatures the single-peaked shape deteriorates, crossing
over towards a double- ground-state structure. A connection is obtained
between the probability distribution for correlation functions and the
underlying distribution of accumulated field fluctuations. Analytical
expressions are in good agreement with numerical results for ,
low , not too small, and near G=1. From a finite-size {\it ansatz} at
, , averaged correlation functions are predicted to
scale with , . From numerical data we estimate y=0.875 \pm
0.025WR/L=1W \sim h_0^{\kappa} f(L h_0^u)\kappa \simeq 0.45u \simeq 0.8f(x)x \to \inftyW \sim
h_0^{\kappa}d=2$.Comment: RevTeX code for 8 pages, 7 eps figures, to appear in Physical Review
E (1999
CO2 dissolution and design aspects of a multiorifice oscillatory baffled column
Dissolution of CO2 in water was studied for a batch vertical multiorifice baffled column (MOBC) with varying orifice diameters (d0) of 6.4-30 mm and baffle open area (α) of 15-42%. Bubble size distributions (BSDs) and the overall volumetric CO2 mass transfer coefficient (KLa) were experimentally evaluated for very low superficial gas velocities, UG of 0.12-0.81 mm s-1, using 5% v/v CO2 in the inlet gas stream at a range of fluid oscillations (f = 0-10 Hz and x0 = 0-10 mm). Remarkably, baffles presenting large do = 30 mm and α = 36%, therefore in the range typically found for single-orifice oscillatory baffled columns, were outperformed with respect to BSD control and CO2 dissolution by the other baffle designs or the same aerated column operating without baffles or fluid oscillations. Flow visualization and bubble tracking experiments also presented in this study established that a small do of 10.5 mm combined with a small value of α = 15% generates sufficient, strong eddy mixing capable of generating and trapping an extremely large fraction of microbubbles in the MOBC. This resulted in increased interfacial area yielding KLa values up to 65 ± 12 h-1 in the range of the UG tested, representing up to 3-fold increase in the rate of CO2 dissolution when compared to the unbaffled, steady column. In addition, a modi fied oscillatory Reynolds number, Re′o and Strouhal number, St' were presented to assist on the design and scale-up of gas-liquid systems based on multiorifice oscillatory ba ffled columns. This work is relevant to gas-liquid or multiphase chemical and biological systems relying on efficient dissolution of gaseous compounds into a liquid medium.BBSRC -European Commissio
Commutative limit of a renormalizable noncommutative model
Renormalizable models on Moyal space have been obtained by
modifying the commutative propagator. But these models have a divergent "naive"
commutative limit. We explain here how to obtain a coherent such commutative
limit for a recently proposed translation-invariant model. The mechanism relies
on the analysis of the uv/ir mixing in general Feynman graphs.Comment: 11 pages, 3 figures, minor misprints being correcte
What does your profile picture say about you?:the accuracy of thin-slice personality judgments from social networking sites made at zero-acquaintance
KO-Homology and Type I String Theory
We study the classification of D-branes and Ramond-Ramond fields in Type I
string theory by developing a geometric description of KO-homology. We define
an analytic version of KO-homology using KK-theory of real C*-algebras, and
construct explicitly the isomorphism between geometric and analytic
KO-homology. The construction involves recasting the Cl(n)-index theorem and a
certain geometric invariant into a homological framework which is used, along
with a definition of the real Chern character in KO-homology, to derive
cohomological index formulas. We show that this invariant also naturally
assigns torsion charges to non-BPS states in Type I string theory, in the
construction of classes of D-branes in terms of topological KO-cycles. The
formalism naturally captures the coupling of Ramond-Ramond fields to background
D-branes which cancel global anomalies in the string theory path integral. We
show that this is related to a physical interpretation of bivariant KK-theory
in terms of decay processes on spacetime-filling branes. We also provide a
construction of the holonomies of Ramond-Ramond fields in Type II string theory
in terms of topological K-chains.Comment: 40 pages; v4: Clarifying comments added, more detailed proof of main
isomorphism theorem given; Final version to be published in Reviews in
Mathematical Physic
Finding Direction in the Search for Selection.
Tests for positive selection have mostly been developed to look for diversifying selection where change away from the current amino acid is often favorable. However, in many cases we are interested in directional selection where there is a shift toward specific amino acids, resulting in increased fitness in the species. Recently, a few methods have been developed to detect and characterize directional selection on a molecular level. Using the results of evolutionary simulations as well as HIV drug resistance data as models of directional selection, we compare two such methods with each other, as well as against a standard method for detecting diversifying selection. We find that the method to detect diversifying selection also detects directional selection under certain conditions. One method developed for detecting directional selection is powerful and accurate for a wide range of conditions, while the other can generate an excessive number of false positives
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