A numerical approach for the numerical optimization of stirrer configurations is presented. The methodology is based on a parametrized grid generator, a flow solver, and a mathematical optimization tool, which are integrated into an automated procedure. The flow solver is based on the discretization of the Navier-Stokes equations by means of the finite-volume method for block-structured, bounda...

MIXING ENHANCEMENT BY DUAL SPEED ROTATING STIRRER by Arnaud Goullet Stirring is a well-known means of fluid mixing due to the emergence of complex patterns in the flow, even at low Reynolds numbers. In this work, we consider a stirrer rotating along a circular trajectory at constant speed. The fluid flow, considered incompressible, inviscid and two dimensional (in a circular container), is mode...

A conventional ultrasonic bath was used to examine the feasibility of forming aqueous spherical gold nanoparticles (GNPs) under atmospheric conditions. The effects of ultrasonic energy on the size and morphology of GNPs were also investigated. Highly monodispersed spherical GNPs were successfully synthesised by sodium citrate reduction in a conventional ultrasonic bath, without an additional he...

In Microbial Fuel Cells (MFCs), a mass transfer impact might be larger than expected because it not only effects the mass transfer losses (substrate flux [1, 2] and removal of waste [2]), but also effects the activation losses (mediator [3-5]) and the ohmic losses (proton transfer [6]). However, the convection/diffusion of the reactant transport from the bulk (reactant transport), which can be ...

The mass transfer process is the subject of many experimental studies in chemical engineering and also one of the most commonly used processes. Unfortunately, the mechanism of this process is still not fully understood, especially when nonstandard methods of intensification of mass transfer are used. In this investigation, the use of an alternating magnetic field action (AMFs) causing mass tran...

This paper presents an attempt to optimize fluidized bed drying of wet and adhesive particles (with an initial diameter of about 580 mm) with the use of stirring, and discusses the influence of stirring on the total drying time. The goal was to demonstrate the positive effect of stirring a fluidized bed to the drying time, to find the optimal parameters (stirrer design, speed, and size). Experi...

An economical bioreactor designed for evaluating the biogas potential of particulate biomass is described. The bioreactor uses a simple stirring apparatus, called the Bordeaux stirrer, to enable gas-tight mixing of fermentation cultures. The apparatus consists of a low-rpm motor connected to a bent steel stir rod, which is placed in a length of flexible plastic tubing inserted through a rubber ...

In this paper predictive model for Metal Matrix Composite (MMCs) has been developed with the use of Artificial Neural Network. Stir casting process has been used to fabricate the fly ash based AL-6063 particulate MMC. The hardness of fly ash based AL-6063 MMC is taken as output variable, however fly ash(FA) percentage of reinforcement in MMC, stirring speed of stirrer and pouring temperature of...

According to the manufacturer (Kodak pathe) of the LR-115 Type 2 films, which are widely used in environmental radioactivity studies, the exposed films should be etched in 10% solution of NaOH, while the temperature of the etching solution is to be kept at 60C. The optimum time of etching depends on different conditions; like geometry of the bath, temperature etc. To determine the optimal etchi...

Cadmium compounds such as cadmium sulfate are used in batteries, pigments and in semiconductor industry. Commercially available cadmium sulfate was purchased and used for the crystal growth. The sample in salt form was dissolved in double distilled water and the saturated solution was prepared. Nearly 38 grams/50 ml are necessary to prepare the saturated solution and the solution was stirred we...