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.

201

Frações da matéria orgânica do solo no cerrado sob sistema agroflorestal no Nordeste do Brasil.

201

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