9 research outputs found
Tocopherol and fatty acids content and proximal composition of four avocado cultivars (Persea Americana Mill)
Avocado pulp is widely regarded as a great source of edible oil containing fat-soluble vitamins and omega-3 fatty acids (FA). However, avocado peel and seeds are also good sources of edible oil and are less explored byproducts. This paper aimed at determining the proximal composition, FA and tocopherol contents of the pulp, peel, and seeds of Quintal, Fortuna, Margarida, and Hass avocado cultivars. The pulps presented high concentrations of oleic acid. In addition, peel and seeds presented lower omega-6/omega-3 ratios than the pulp. There was also a considerable amount of tocopherol in the peel and seeds, especially in Hass peel (230.7 mg/100 g). According to the results, the peel and seeds of avocado that are considered byproducts, can be utilized in food industry
Statistics of the contact network in frictional and frictionless granular packings
Simulated granular packings with different particle friction coefficient mu
are examined. The distribution of the particle-particle and particle-wall
normal and tangential contact forces P(f) are computed and compared with
existing experimental data. Here f equivalent to F/F-bar is the contact force F
normalized by the average value F-bar. P(f) exhibits exponential-like decay at
large forces, a plateau/peak near f = 1, with additional features at forces
smaller than the average that depend on mu. Computations of the force-force
spatial distribution function and the contact point radial distribution
function indicate that correlations between forces are only weakly dependent on
friction and decay rapidly beyond approximately three particle diameters.
Distributions of the particle-particle contact angles show that the contact
network is not isotropic and only weakly dependent on friction. High
force-bearing structures, or force chains, do not play a dominant role in these
three dimensional, unloaded packings.Comment: 11 pages, 13 figures, submitted to PR
Structural transitions in granular packs: statistical mechanics and statistical geometry investigations
We investigate equal spheres packings generated from several experiments and
from a large number of different numerical simulations. The structural
organization of these disordered packings is studied in terms of the network of
common neighbours. This geometrical analysis reveals sharp changes in the
network's clustering occurring at the packing fractions (fraction of volume
occupied by the spheres respect to the total volume, ) corresponding to
the so called Random Loose Packing limit (RLP, ) and Random
Close Packing limit (RCP, ). At these packing fractions we
also observe abrupt changes in the fluctuations of the portion of free volume
around each sphere. We analyze such fluctuations by means of a statistical
mechanics approach and we show that these anomalies are associated to sharp
variations in a generalized thermodynamical variable which is the analogous for
these a-thermal systems to the specific heat in thermal systems.Comment: 7 pages, 6 figure
Analysis of damping in particle-reinforced superplastic zinc composites
The damping behavior of superplastic zinc (SPZ) participate composites with up to 42.5 vol pet spherical TiC particles (3 /im in diameter) was studied in the 25 °C to 330 °C temperature range using a low frequency torsion pendulum. The observed damping at room temperature was modeled as a combination of a diffusion-controlled dislocation relaxation and a grain boundary relaxation. Addition of TiC produced a lower dislocation damping contribution at room temperature, but this loss was offset by an increased contribution from the grain boundary relaxation. An increase in the elastic modulus was also observed for the composite. The validity of a theoretical model for predicting changes in the grain boundary relaxation peak temperature resulting from the introduction of large nondeforming particles was tested. This study demonstrates that grain sliding in SPZ alloys occurs by cooperative sliding of grain clusters containing three to five grains. The activation energy for this process was found to be 111 kJ/mole (1.15 eV), which is in agreement with previously published values for grain sliding in SPZ. A second internal friction peak at a temperature just below the eutectoid transformation temperature was also observed and this peak was associated with recrystallization
Micromechanics of diffusion-induced damage evolution in reinforced polymers
10.1016/j.compscitech.2010.11.027Composites Science and Technology713333-342CSTC