The model given in this report and the rotating disk method provide a useful combination in the study of dental enamel and hydroxyapatite dissolution kinetics. The present approach is a significant improvement over earlier studies, and both the ionic activity product that governs the dissolution reaction and the apparent surface dissolution reaction rate constant may be simultaneously obtained....

The dissolution kinetics of the cotnn~on crystalline forms of cholesterol (anhydrate and monohydrate) were studied in free and conjugated chenodeoxycholate and ursodeoxycholate solutions by static disk, rotating disk, and powder dissolution techniques. 'The dissolution kinetics of both forms of cholesterol were found to be non-diffusion controlled, i.e., the detachment rate of cholesterol molec...

Microbial reduction of ferric iron is partly dependent on Fe hydroxide particle size: nanosized Fe hydroxides greatly exceed the bioavailability of their counterparts larger than 1 μm. Citrate as a low molecular weight organic acid can likewise stabilize colloidal suspensions against aggregation by electrostatic repulsion but also increase Fe bioavailability by enhancing Fe hydroxide solubility...

The dissolution rates of cholesterol in model bile salt solutions are controlled by diffusion in slowly flowing bile and by interfacial kinetics in rapidly flowing bile. At low flow, dissolution varies with the square root of bile flow and can be predicted, a priori, from existing correlations of mass transfer. At high bile flow, dissolution is independent of bile flow and is probably dominated...

  Abstract   The effect of mechanical activation using an attrition mill on the particle size of an ilmenite concentrate and its effect on the ability of the concentrate for Iron separation during hydrochloric acid leaching and the kinetics of the dissolution process have been investigated. It was observed that mechanical activation in an attritor significantly enhances the dissolution of iron ...

Preparation and in vitro characterization of floating microparticles loaded with cimetidine (FMC) for oral delivery was the objective of this study. Non-solvent addition coacervation technique using hydroxypropylmethylcellulose (HPMC) as the rate controlling polymer was employed to achieve FMC. Three formulations of FMC were prepared and optimized regarding encapsulation efficiency and dissolut...

The reductive dissolution of hematite (alpha-Fe2O3) was investigated in a flow-through system using AH2DS, a reduced form of anthraquinone-2,6-disulfonate (AQDS), which is often used as a model electron shuttling compound in studies of dissimilatory microbial reduction of iron oxides. Influent flow rate, pH, and Fe(II) and phosphate concentrations were varied to investigate the redox kinetics i...

Atmospheric deposition is a major source of trace metals in marine surface waters and supplies vital micronutrients to phytoplankton, yet measured aerosol trace metal solubility values are operationally defined, and there are relatively few multi-element studies on aerosol-metal solubility in seawater. Here we measure the solubility of aluminum (Al), cadmium (Cd), cobalt (Co), copper (Cu), iron...

The dissolution of deposited, protective iron carbonate fi lms in oil and gas transportation pipelines may drastically enhance corrosive processes on steel surfaces, and thus, seriously affect the longevity of the equipment in use. An investigation had been carried out to get a better understanding of the kinetics and underlying mechanism of fi lm dissolution, as well as to provide baseline dat...

We present a simulation based study, by combining several models involving multiple time scales and physical processes, which govern the interfacial stress corrosion cracking (SCC) in grain boundaries, layered composites or bi-materials, and the mechanisms of inhibition using ‘smart’ agents. The inhibiting agents described herein, automatically sense the initiation of damage, migrate to the sit...