Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 34 for “"Agitation speed"”.
-
Minimum agitation speed for solid suspension and mixing time in a torispherical -bottomed pharmaceutical stirred tank under different baffling conditions
The minimum agitation speed, NS, required to just suspend solid particles dispersed in water was experimentally determined in this work for a glass-lined type of mixing tank provided with a torispherical bottom and agitated with a retreat-blade impeller under different baffling configurations. Ns …
-
Novel experimental method for the determination of the minimum agitation speed for solids suspension in flat-bottomed stirred tank reactors
Knowledge of the minimum agitation speed, Njs, required to suspend finely divided solids in vessels stirred by an impeller is a critical parameter to properly operate industrial tanks in a large number of industrial operations. The most common experimental approach to measure N_{js} is that of …
-
Experimental determination of the agitation requirements for solids suspension in dissolution systems using a mini paddle apparatus
… available on mini vessels, and especially on the agitation speed needed to prevent "coning" effects. Typically during dissolution testing, a disintegrating tablet becomes rapidly fragmented, and the resulting solid particles may or may not become suspended depending on the agitation speed of the …
-
Producing Omega-3 Polyunsaturated Fatty Acids from Biodiesel Waste Glycerol by Microalgae Fermentation
… difficult. The mycelium can stick to the agitation blades resulting in mechanical problems. In addition, this filamentous morphology prevents adequate amounts of oxygen from reaching some cells resulting in decreased productivities. The focus of this research was to control the …
-
Scale-Up the Use of a Microbubble Dispersion to Increase Oxygen Transfer in Aerobic Fermentation of Baker's Yeast
… of yeast Saccharomyces cerevisiae, cultured at agitation speeds of 150 rpm and 500 rpm, were compared for oxygen supplied by ordinary air sparging and by MBD sparging. Both air sparged and MBD systems were supplied air at equivalent volumetric flow rates. The volumetric oxygen transfer …
-
Evaluation of the effect of growth conditions on lipid production by Papiliotrema laurentii UFV-1 in culture media containing xylose
… aimed to evaluate the effects of pH, C/N ratio, agitation speed, initial cell density and temperature on lipid production by P. laurentii UFV-1, a new yeast strain isolated from soil. We performed the centered face central composite design, with 25 combinations between the factors studied and …
-
Experimental determination of the mixing requirements for solid suspension in pharmaceutical stirred tank reactors
… been fully studied, such as the minimum impeller agitation speed, N_{js}, to just suspend finely divided solids. In this work, N_{js} was experimentally obtained for a number of different pharmaceutically-relevant agitation systems including vessels with different types of bottoms (torispherical …
-
Experimental determination of solids suspension with angled impeller in a pharmaceutical mixing vessel
… it is critical to know the value of the minimum agitation speed at which solids become just suspended,N_{js}. Despite their common use in industry, and especially the pharmaceutical industry, these systems have received little attention in the literature in general and as far as their ability to …
-
Study of the C-curve fluctuation analysis for a CSTR reactor
… ranging from 52 (ml/min) to 213 (ml/min) and agitation speeds from 0.00 rpm to 200 rpm were covered. The C-curve (concentration curve) was found to be reproducible to within ± 5 % at agitation speed greater than 20 rpm. The fluctuations for a C-curve were extracted and standard deviation was …
-
Experimental investigation of mixing time in a stirred, torispherical-bottomed tank equipped with a retreat-blade impeller
… method. Experiments were performed when the agitation speed was varied in order to establish a correlation between mixing time and rotational speed for all systems. The mixing time in the partially baffled system was found to decrease with increasing impeller speeds and the predicted mixing …
-
Growth of mixed cultures of moderate thermophiles for commercial heap bioleaching of low-grade copper-sulphide ores
… The effect of carbon dioxide concentration and agitation speed on the microbial composition of a mixed moderate thermophilic culture was investigated. Three stirred tank reactors (STRs) and a shake flask were inoculated with the culture and maintained at 50 °C. Two STRs were sparged with air …
-
Simulation of palm oil and methanol mixing in stirred tank by implement a normal and fractal baffles
… and process variables, such as the impeller agitation speed. In addition, the feeding position of the methanol. Finally, a quantitative comparison of different stirring systems and scale-up studies was set.
-
Single and multiphase mixing in partially filled stirred vessels
… emptied or filled. Even when H/T<1, sufficient agitation must still be provided in order to attain the desired process objectives. When the impeller submergence is reduced as a result of lowering the liquid level, the fluid dynamics of even a single-phase stirred liquid can become quite complex, …
-
The purification of industrial wastewater to remove heavy metals and investigation into the use of zeolite as a remediation tool
… of initial solution concentration, effect of agitation speed and effect of pre-treatment of adsorbent and evaluated their impact on the efficiency of the zeolite in the removal of heavy metals from industrial wastewater. The kinetic studies showed that the capacity of the adsorbents for the …
-
Vanadium and titanium extraction from titaniferous slag using a roast-leach process
… 120 minutes leaching time, s:l ratio of 1:4, and agitation speed of 350 rpm. The produced water leach residue was further subjected to acid leaching using HCl as a lixiviant with 20% acid concentration, at 110°C, 24 hours, s:l ratio of 1:4, and agitation speed of 350 rpm. The acid leaching stage …
-
Release of cortisol from lanolin alcohol-providone films
… films was studied in terms of the effect of agitation, film thickness and drug concentration. The rate of release of Cortisol from lanolin alcohol films was not affected by the intensity of agitation. Moreover, the film matrix was found to remain essentially intact throughout the release …
-
Remediation of acid mine drainage using natural zeolite
… Higher metal uptakes were achieved by increasing agitation speed, initial solution pH, particle size reduction, and thermal pre-treatment. The rate limiting step for this process was intraparticle diffusion. Column studies showed that natural zeolite was capable of removing heavy metals from a …
-
In vitro bioactivities of anodised titanium in mixtrue of B-Glycerophosphate and calcium acetate for biomedical application
… β-GP + 0.04 M CA) , anodising time (5-10 mins), agitation speed (300-1500 rpm), ultrasonic amplitude (20-60 μm) and bath temperature (4-100 °C) were varied to investigate the impact on the surface properties of titanium. The results showed that surface of the titanium foil appeared to be highly …
-
The effect of waste cooking oil methanol molar ratio on yield and properties of biodiesel produced in a mini plant
… time of 2 hours, temperature of 600C and 600 rpm agitation speed. The properties of biodiesel such as Free Fatty Acid (FFA), water content, flash point, acid value, density, kinematic viscosity, and moisture content was investigated to fulfil standard ASTM D7461 and EN14013 Fatty Acid Methyl Ester …
-
Mass transfer characteristics of two-aqueous-phase liquid-liquid mixtures
… dispersed phase hold-up and impeller speed were investigated for the salt-PEG system. An increase in agitation speed in the range 300 rpm to 1000 rpm caused a decrease in mean drop diameter, e.g. from 50 m to 15 m. A characteristic bimodal drop size distribution was established within …
Page 1 of 2