Surface modification for enhanced corrosion resistance using fluid bed reactor chemical vapour deposition (FBR-CVD)

The use of materials with otherwise desirable mechanical properties is often problematic in practice as a result of corrosion. Susceptibility may arise for a number of reasons, including an electrochemically heterogeneous surface or destabilisation of a passive film. These shortcomings have historically been overcome through the use of various coatings or claddings. However, a more robust surface layer with enhanced corrosion resistance could possibly be produced via local surface alloying using a fluidised bed. A fluidised bed treatment allows a surface to be alloyed, producing a distinct surface layer up to tens of microns thick. Surface alloying additions can be selected on the basis of whether they are known or suspected to enhance the corrosion resistance of a particular material, whilst at a minimum, surface alloying likely provides a more electrochemically homogeneous surface. Electrochemical evaluations using potentiodynamic polarisations in NaCl electrolytes have shown chromised plain carbon and stainless steel surfaces have decreased rates of corrosion, decreased passive current densities, and ennobled pitting potentials relative to untreated specimens.

RiboSys, a high-resolution, quantitative approach to measure the in vivo kinetics of pre-mRNA splicing and 3'-end processing in Saccharomyces cerevisiae

We describe methods for obtaining a quantitative description of RNA processing at high resolution in budding yeast. As a model gene expression system, we constructed tetON (for induction studies) and tetOFF (for repression, derepression, and RNA degradation studies) yeast strains with a series of reporter genes integrated in the genome under the control of a tetO7 promoter. Reverse transcription and quantitative real-time-PCR (RT-qPCR) methods were adapted to allow the determination of mRNA abundance as the average number of copies per cell in a population. Fluorescence in situ hybridization (FISH) measurements of transcript numbers in individual cells validated the RT-qPCR approach for the average copy-number determination despite the broad distribution of transcript levels within a population of cells. In addition, RT-qPCR was used to distinguish the products of the different steps in splicing of the reporter transcripts, and methods were developed to map and quantify 3′-end cleavage and polyadenylation. This system permits pre-mRNA production, splicing, 3′-end maturation and degradation to be quantitatively monitored with unprecedented kinetic detail, suitable for mathematical modeling. Using this approach, we demonstrate that reporter transcripts are spliced prior to their 3′-end cleavage and polyadenylation, that is, cotranscriptionally.

Corrosion impact on drinking water distribution systems : a review and future research direction

At present water treatment and distribution is of high priority to ensure that communities have access to safe and affordable drinking water. Current information states that in the United States a total annual cost of $36 billion (US) is spent replacing aging infrastructure, lost water from unaccounted-for leaks, corrosion inhibitors, internal mortar linings, external coatings, and cathodic protection as a result of corrosion. In order to reduce the cost incurred as a result of corrosion in the water distribution industry, it is essential that better corrosion management and preventative strategies are implemented. However through investigation of research previously undertaken by others, it was found that there was a lack of study of corrosion within distribution systems in the tropics taking into account the related seasonal temperature variations. To assist in the development of management strategies to improve the outcomes of drinking water distribution systems, the authors propose to implement a pilot study involving the installation of a corrosion reactor based on standard corrosion assessment technologies in a water distribution system located in the tropics.

Evaluation of chlorine decay kinetics expressions for drinking water distribution systems modelling

The decay of chlorine in drinking water involves a complex set of reactions that is usually simplified to first order kinetics in models of water quality in distribution systems. However, to be useful in optimising chlorine dosing regimes, the kinetics expression should accurately describe the shape of the chlorine decay curve for different chlorine doses and be able to simulate re-chlorination. After considering the nature of the reactions involved in chlorine decay, five simplified reaction schemes were evaluated for their suitability to describe chlorine concentration in bulk water. Each scheme was fitted to a sample of experimental data of chlorine decay in raw water obtained from Warragamba Dam (the major source of water supplied to Sydney, Australia). A scheme involving two parallel reactions of organic carbon compounds with chlorine is both necessary and sufficient to satisfy the requirements of modelling chlorine decay accurately.