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Silver Content (silver + content)

Distribution by Scientific Domains
Polymers and Materials Science75%

Selected Abstracts

Chronic effects of silver exposure on ion levels, survival, and silver distribution within developing rainbow trout (Oncorhynchus mykiss) embryos

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2001
Christine M. Guadagnolo
Abstract Rainbow trout embryos were chronically exposed to silver (as AgNO3) in moderately hard water (120 mg CaCO3/L, 0.70 mM Cl,, 1.3 mg/L dissolved organic matter, 12.3 ± 0.1 °C) at nominal concentrations of 0.1, 1, and 10 ,g/L (measured = 0.117 ± 0.008, 1.22 ± 0.16, and 13.51 ± 1.58 ,g/L, respectively) to investigate the effects on mortality, ionoregulation, and silver uptake and distribution of the embryo. Mortalities in the low concentrations (0.1 and 1.2 ,g/L) were not significantly different from controls throughout embryonic development (days 1,32 postfertilization). Mortalities of embryos in the 13.5-,g/L treatment reached 56% by day 32 postfertilization (33% when accounting for control mortality), by which time more than 50% of surviving embryos had hatched. Accumulation of silver in whole embryos of 1.2- and 13.5-,g/L treatments reached the highest concentrations of 0.13 and 0.24 ,g/g total silver, respectively, by day 32, but whole embryo silver burden was not correlated with mortality. Silver concentrations in different compartments of the whole embryo (chorion, dissected embryo, and yolk) were greatest just before hatch and were higher in the chorion for all experimental treatments. Up to 85% of total whole embryo silver content was bound to the chorion, which acts as a protective barrier during silver exposure. Whole embryo Na+ concentration in the 13.5-,g/L treatment was significantly reduced relative to controls from days 23 to 32 postfertilization, and levels in the embryo were reduced by 40% at day 32 postfertilization, indicating that silver toxicity in the whole embryo is associated with an ion regulatory disturbance that is similar to the acute effect of AgNO3 in juvenile and adult trout. [source]

Giant Permittivity of a Bismuth Zinc Niobate,Silver Composite

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 11 2007
Sumesh George
Bismuth zinc niobate,Silver (BZN,Ag) composites were prepared by the solid-state ceramic route. The sintering temperature of BZN,Ag composites was lowered to 850°C/2 h. The structure and surface morphology of the composites were investigated using X-ray diffraction and optical microscope. The dielectric and conducting properties of the composites were systematically investigated with the volume fraction of silver in the frequency range from 1 KHz to 1 MHz. The dielectric constant of the composite increases with the silver content and is in good agreement with the power law below the percolation limit. Addition of 0.14 volume fraction of silver increases the dielectric constant of BZN+2 wt% B2O3 from 150 to 2350 at 1 MHz. However, 15 volume percentage of silver loading results in a large permittivity of (,r),105 with a low dielectric loss (tan ,,10,2) at 1 MHz. Subsequent increase in silver loading decreases the dielectric constant. The BZN,B2O3,Ag composite with large permittivity may find applications in electromechanical and tunable devices. [source]

Effect of Silver on the Sintering and Grain-Growth Behavior of Barium Titanate

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2000
Chin-Yi Chen
Silver and its alloys frequently are used as electrode material for BaTiO3 -based dielectrics. In the present study, a small amount of fine silver particles have been intimately mixed with BaTiO3 powder. The sintering and grain-growth behavior of the silver-doped BaTiO3 in air are investigated. The solubility of silver in BaTiO3, as revealed by lattice-parameter measurement, electrical measurement, and electron probe microanalysis, is <300 ppm. The densification of BaTiO3 is slowed slightly by the addition of silver inclusions. However, the presence of a small amount (<0.3 wt%) of silver increases the amount and size of abnormal grains. When the silver content is >0.3 wt%, the grain growth of BaTiO3 then is prohibited by the silver inclusions. [source]

The role of a third component on the conductivity behavior of ternary epoxy/Ag conductive composites

POLYMER COMPOSITES, Issue 4 2002
W. Jia
Conductive adhesives, based on highly filled silver particles dispersed in a liquid epoxy resin, with an aliphatic amine [diethyltriamine (DETA)] as a curing agent, were investigated. A third component was added to the epoxy/Ag system to obtain composites of better conductivity, or similar conductivity but at lower silver contents, to modify the conductive adhesive properties, and also to reduce cost. Epoxy/Ag/carbon black (CB), epoxy/Ag/carbon fibrils (CF), epoxy/Ag/SiO2 and epoxy/Ag/dispersant composites were thus studied. The effect of high curing temperature on the uniformity and resulting conductivity level was also studied. The studied systems, excluding the epoxy/Ag/CB composite, exhibited enhanced conductivities. The microstructure of most of the systems was studied by scanning electron microscopy (SEM). The micrographs produced have served to establish structure-property relations for better understanding of the observed phenomena. [source]