16,991 research outputs found
Natural waters in Amazonia. III. Ammonium molybdate-reactive silica
Natural waters of the Amazonian Tertiary formations along the Manaus-Itacoatjara Road were studied with respect to variations in average seasonal and yearly soluble silica content. In general the variations are small and concentrations very low, for all input fractions, i. e., rainfall, stemflow, and throughfall [about 90 percent of the total (470 analyses) lower than 1.0 mg/l]. While 90 percent of total ground water analyses (excluding well IV 3) have soluble silica concentrations lower than 1.5 mg/l, high rain forest stream waters are slightly higher (90 percent of all values lower than 2.0 mg/l). The Rio Negro waters show 90 percent of the total samples analyzed between 2.0 mg/l and 3.0 mg/l soluble silica
Ion specificity and the theory of stability of colloidal suspensions
A theory is presented which allow us to accurately calculate the critical
coagulation concentration (CCC) of hydrophobic colloidal suspensions. For
positively charged particles the CCC's follow the Hofmeister (lyotropic)
series. For negatively charged particles the series is reversed. We find that
strongly polarizable chaotropic anions are driven towards the colloidal surface
by electrostatic and hydrophobic forces. Within approximately one ionic radius
from the surface, the chaotropic anions loose part of their hydration sheath
and become strongly adsorbed. The kosmotropic anions, on the other hand, are
repelled from the hydrophobic surface. The theory is quantitatively accurate
without any adjustable parameters. We speculate that the same mechanism is
responsible for the Hofmeister series that governs stability of protein
solutions.Comment: Phys. Rev. Lett. (in press
Estimação de parcelas perdidas em experimentos agrícolas utilizando-se o PROC GLM do SAS.
Introdução; Desenvolvimento e programas; Programa para estimação de parcelas perdidas em blocos ao acaso; Programa para estimação de parcelas perdidas em quadrado latino.bitstream/CNPA/14623/1/DOC76.pd
Effect of sewage sludge on the rot and seedling damping-off of bean plants caused by sclerotium rolfsii.
Made available in DSpace on 2017-09-19T00:12:30Z (GMT). No. of bitstreams: 1
SantosEffect6416.pdf: 194885 bytes, checksum: 1d24965fdae548bd814dae59968981d8 (MD5)
Previous issue date: 2006-10-0
Initial development of eucalyptus grandis (eucalyptus) in field benefited with biochar in Sinop / MT
- …