The development of phytoplankton communities was studied in floating enclosures. The enclosures were supplied with either surface water or water from 40 m depth. Nutrients with or without silicate were added in some of the experiments, while others recieved no artificial fertilization. It is shown that diatom dominance occurred irrespective of season if silicate concentration exceeded a thresho...

We report the spectroscopic detection of silicate emission at 10 and 18μm in five PG quasars, the first detection of these two features in galaxies outside the Local Group. This finding is consistent with the unification model for Active Galactic Nuclei (AGNs), which predicts that an AGN torus seen pole-on should show a silicate emission feature in the mid-infrared. The strengths of the detecte...

Recently, the demolition of old houses and the construction of new buildings in Kathmandu valley are in the peak which in turn generates a huge amount of construction waste. This construction waste is rich source of alumino-silicate and thus used as raw material for the synthesis of geopolymer in this study. Geopolymers have been synthesized from construction waste using NaOH and Na2SiO3 as act...

Silicate hydration is prevalent in natural and technological processes, such as, mineral weathering, glass alteration, zeolite syntheses and cement hydration. Tricalcium silicate (Ca3SiO5), the main constituent of Portland cement, is amongst the most reactive silicates in water. Despite its widespread industrial use, the reaction of Ca3SiO5 with water to form calcium-silicate-hydrates (C-S-H) s...

First principles calculations are employed to provide a fundamental understanding of the relationship between the reactivity of synthetic calcium silicate phases and their electronic structure. Our aim is to shed light on the wide range of hydration kinetics observed in different phases of calcium silicate. For example, while the dicalcium silicate (Ca2SiO4) phase slowly reacts with water, the ...

hydrolysis of ethylene-vinyl acetate copolymer in alkaline conditions using two systems of naoh/methanol and koh/isopropanol has been studied and the formation of ethylene-vinyl alcohol copolymer was systematically examined using nmr spectroscopy and dsc measurements. vinyl acetate weight percentage and the degree of hydrolysis were calculated from nmr spectroscopy and it is shown that hydrolys...

The aim of this study was to evaluate the influence of a calcium silicate-based sealer (iRoot SP), with or without a core material, on bond strength to radicular dentin, in comparison with various contemporary root filling systems. Root canals of freshly extracted single-rooted teeth (n = 60) were instrumented using rotary instruments. The roots were randomly assigned to one of the following ex...

daily, organophosphorus compounds (ops) in human life, has found wide applications. although ops have biodegradability potential, they induce clinical problems in humans and other organism. different methods are used to detoxify these compounds. in the meantime, biodegradation is preferred as a compatible way to the environment since it produces less toxic compounds. enzymes capable to degrade ...

cow’s milk whey consists of many protein components and some of them are antigens to human and known to modulate immune responses. enzymatic hydrolysis is a useful method to modify proteins with allergenicity. the objective of this study was to identify whether the in vitro enzymatic hydrolysis could reduce the allergenicity of whey protein concentrates (wpc). in  this study, wpc were hydrolyze...

The theory of elastic group transfer for the binding and release rate constants for nucleotides in F1-ATPase as a function of the rotor angle is further extended in several respects. (i) A method is described for predicting the experimentally observed lifetime distribution of long binding events in the controlled rotation experiments by taking into account the hydrolysis and synthesis reactions...