5,505 research outputs found
Ecologia microbiana do solo.
Fatores abióticos que afetam os microrganismos; Temperatura do solo; pH do solo; Fontes de energia e substratos orgânicos; Nutrientes minerais; Práticas de manejo e cultivo dos solos; Interação entre microrganismos; Interações microbianas de importância para a produção agrícola.bitstream/item/35904/1/Doc164.pd
Screening effects in flow through rough channels
A surprising similarity is found between the distribution of hydrodynamic
stress on the wall of an irregular channel and the distribution of flux from a
purely Laplacian field on the same geometry. This finding is a direct outcome
from numerical simulations of the Navier-Stokes equations for flow at low
Reynolds numbers in two-dimensional channels with rough walls presenting either
deterministic or random self-similar geometries. For high Reynolds numbers,
when inertial effects become relevant, the distribution of wall stresses on
deterministic and random fractal rough channels becomes substantially dependent
on the microscopic details of the walls geometry. In addition, we find that,
while the permeability of the random channel follows the usual decrease with
Reynolds, our results indicate an unexpected permeability increase for the
deterministic case, i.e., ``the rougher the better''. We show that this complex
behavior is closely related with the presence and relative intensity of
recirculation zones in the reentrant regions of the rough channel.Comment: 4 pages, 5 figure
Optical limiting behavior of bismuth oxide-based glass in the visible range
The authors report experimental results on the optical limiting behavior of a bismuth oxide-based glass by exciting the samples with nanosecond laser pulses at 532 and 598 nm. The results show that two-photon and free-carrier absorption processes contribute for the nonlinear absorption. Values for β, the two-photon absorption coefficient, and σe, the absorption cross section due to free carriers, were determined. The values for β and σe are dependent on the amount of bismuth oxide in the glass composition
Different soil tillage systems influence accumulation of soil organic matter in organic agriculture.
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Frações da matéria orgânica do solo no cerrado sob sistema agroflorestal no Nordeste do Brasil.
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Rational bioprospecting and identi cation of genes from sugarcane endophytic fungi Epicoccum nigrum and Epicoccum sp. involved in the biosynthesis of bioactive metabolites.
Uso de hipoclorito de sódio para acelerar a emergência das plântulas e desenvolvimento das mudas de cafeeiro.
A Comparative Evaluation of Two Distributed Hydro-Sedimentological Models in The Semiarid Region of the State of Paraíba, Brazil
Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv
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