Surface diagnostics for scale analysis.

S Dunn; S Impey; C Kimpton; S A Parsons; J Doyle; B Jefferson

Home/Archive/PubMed

PubMed · 14982180

Surface diagnostics for scale analysis.

S Dunn·S Impey·C Kimpton·S A Parsons·J Doyle·B Jefferson

View original source ↗Export metadata ↓

Abstract

Stainless steel, polymethylmethacrylate and polytetrafluoroethylene coupons were analysed for surface topographical and adhesion force characteristics using tapping mode atomic force microscopy and force-distance microscopy techniques. The two polymer materials were surface modified by polishing with silicon carbide papers of known grade. The struvite scaling rate was determined for each coupon and related to the data gained from the surface analysis. The scaling rate correlated well with adhesion force measurements indicating that lower energy materials scale at a lower rate. The techniques outlined in the paper provide a method for the rapid screening of materials in potential scaling applications.

Explore related subjects

Chemical Precipitation Corrosion Hemostatics Magnesium Compounds Materials Testing Microscopy, Atomic Force Phosphates Polymethyl Methacrylate Polytetrafluoroethylene Steel Struvite Water Supply Journal Article Research Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

S Dunn, S Impey, C Kimpton, S A Parsons, J Doyle, B Jefferson. 2004. Surface diagnostics for scale analysis.. https://pubmed.ncbi.nlm.nih.gov/14982180/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2005

A novel flow cytometry-based method for analysis of expression levels in Escherichia coli, giving information about precipitated and soluble protein.

A high throughput method for screening of protein expression is described. By using a flow cytometer, levels of both soluble and precipitated protein can simultaneously be assessed in vivo. Protein fragments were fused to the N-terminus of enhanced GFP and the cell samples were analysed using a flow cytometer. Data concerning whole cell fluorescence and light scattering was collected. The whole cell fluorescence is probing intracellular concentrations of soluble fusion proteins. Concurrently, forward scattered light gives data about inclusion body formation, valuable information in process optimisation. To evaluate the method, the cells were disrupted, separated into soluble and non-soluble fractions and analysed by gel electrophoresis. A clear correlation between fluorescence and soluble target protein was shown. Interestingly, the distribution of the cells regarding forward scatter (standard deviation) correlates with the amount of inclusion bodies formed. Finally, the newly developed method was used to evaluate two different purification tags, His(6) and Z(basic), and their effect on the expression pattern.

Chemical Precipitation↗

PubMed2005

Ibuprofen-loaded nanoparticles prepared by a co-precipitation method and their release properties.

A co-precipitation method was established to fabricate nano-scale core-shell particles, by which poor water-soluble drugs can be effectively dispersed with rather good stability during storage. Exemplified with formation of ibuprofen (Ib) nanoparticles stabilized by DEAE dextran (Ddex), the process includes precipitation of Ib in a supersaturated solution and deposition of Ddex onto the precipitated Ib particles through electrostatic interaction. Characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM), dynamic light scattering (DLS) and zeta potential, the core-shell structure of the particles formed at pH 6.0 with a Ddex/Ib weight ratio of 5:1 was identified with Ib being the core and Ddex being the shell. As a comparison, particles formed at other pH values and other Ddex/Ib ratios were also studied. Along with increase of the Ddex/Ib ratio or pH value of the final aqueous solution, the particle size was decreased, demonstrating that the particle sizes could be readily tuned by variation of the fabrication parameters. At conditions that the Ib concentration was lower than its supersaturated value, for example at higher pH value, instead of co-precipitation mechanism, forces such as electrostatic complexation dominate the formation of Ddex-Ib particles. Moreover, drug entrapment was mainly dependent on the Ib solubility regardless of the ratio between Ddex and Ib, while the drug content was decreased as a function of Ddex/Ib ratio. In vitro release studies showed that the loaded Ib could be again released in a burst manner during the initial stage, followed with a slow rate. The final released amount of Ib showed a positive correlation with the bulk pH value, e.g. approximately 60, 80 and 90% of the loaded Ib were released in pH 1.0, 5.8 and 7.4 buffered solutions after incubation for 40 h, respectively.

Chemical Precipitation↗

PubMed2005

AgCl precipitates in isolated cuticular membranes reduce rates of cuticular transpiration.

Counter diffusion of chloride, applied as NaCl at the inner side of isolated cuticles, and silver, applied as AgNO(3) at the outer side, lead to the formation of insoluble AgCl precipitates in isolated cuticles. AgCl precipitates could be visualized by light and scanning electron microscopy. The presence of AgCl precipitates in isolated cuticles was verified by energy dispersive X-ray analysis. It is argued that insoluble AgCl precipitates formed in polar pores of cuticles and as a consequence, cuticular transpiration of 13 out of 15 investigated species was significantly reduced up to three-fold. Water as a small and uncharged but polar molecule penetrates cuticles via two parallel paths: a lipophilic path, formed by lipophilic cutin and wax domains, and a aqueous pathe, formed by polar pores. Thus, permeances P (m s(-1)) of water, which is composed of the two quantities P (Lipid) and P (Pore), decreased, since water transport across polar pores was affected by AgCl precipitates. Cuticles with initially high rates of cuticular transpiration were generally more sensitive towards AgCl precipitates compared to cuticles with initially low rates of transpiration. Results presented here, significantly improves the current model of the structure of the cuticular transpiration barrier, since the pronounced heterogeneity of the cuticular transport barrier, composed of lipophilic as well as polar paths of diffusion, has to be taken into account in future.

Chemical Precipitation↗