A novel method for preconcentration of methylmercury and inorganic mercury from water samples was developed involving the determination of ngl(-1) levels of analytes retained on the silica C(18) solid sorbent, previous complexation with ammonium pyrrolidine dithiocarbamate (APDC), by slurry sampling cold vapor atomic absorption spectrometry (SS-CVAAS) in a flow injection (FI) system. Several va...

Objectives: Traditional method of optimization is lengthy and time consuming while response surface methodology evaluates the effects multiple factors their interactions on one or more variables with fewer experiments. The aim present study green synthesized black tea nanoparticles using central composite design. Materials Methods: 5, 15, 25% concentrations were reacted 10, 15 mM Silver nitrate...

The response to a localized perturbation of an excitable medium under stirring by chaotic advection is investigated. It is found that below a critical stirring rate a localized perturbation produces a coherent global excitation of the system. For very slow stirring, however, the coherence of the global excitation is gradually lost. We propose a simple model to describe the effect of the flow on...

The e ects of stirring on the bulk etch rate of LR 115 detector has been investigated. The surface pro6le measurement method using an instrument called Form Talysurf has been used to measure the thickness of the active layer of the LR 115 detectors. The etchant was 10% aqueous solution of NaOH maintained at 60◦C. The bulk etch rate under magnetic stirring has been found to be 6:65 ± 0:34 m h−1 ...

Transport in laminar flows is governed by chaotic stirring and striation in long thin filaments. In turbulent flows, isotropic mixing dominates and tracers behave like stochastic variables. In this paper, we investigate the quasi-turbulent, intermediate regime where both chaotic stirring and turbulent mixing coexist. In these flows, the most common in nature, aperiodic Lagrangian coherent struc...

To reduce the membrane fouling in an immersed membrane bioreactor (MBR) during the treatment of food wastewater, an additional continuous stirring was introduced. The results showed that both a better membrane performance and a higher degradation efficiency for food wastewater were obtained. The membrane contributed mostly in concentrating the activated sludge. The bioreactor ensured the degrad...

Our aim in this work is the synthesis and study optical and structural properties of gold nanoparticles.Gold (III) chloride trihydratewas taken as metal precursor, ascorbic acid at the presence of an appropriate amount of NaOH as reducing agent and polyvinylpyrrolidonek-30 (PVP K-30) as a stabilizing and capping agent. The reaction was performed in high-speed stirring rate at room temperature.S...

The nanoparticles of gold doped with various percentage of copper (Cu 10%, 25%, 75%) were synthesized by wet-chemical method at room temperature. Copper (II) sulfate and gold (III) chloride trihydride was taken as the metal precursor and ascorbic acid as a reducing agent and anhydride maleic as surfactant. The reaction is performed with high-speed stirring at room temperature under nitrogen atm...