Crack damage in polymers and composites: a review

Polymer-based materials are extensively used in various applications such as aircrafts, civilian structures, oil and gas platforms and electronics. They are, however, inherently damage prone and over time, the formation of cracks and microscopic damages influences the thermo-mechanical and electrical properties, which eventually results in the total failure of the materials. This paper provides an overview of the principal causes of cracking in polymer and composites and summarizes the recent progress in the development of non-destructive techniques in crack detection. Furthermore, recent progress in the development of bio-inspired self-healing methods in autonomic repair is discussed.

Ocean governance and risk management

The high seas have always engendered a range of emotions and reactions from humans. Curiosity, fear, even terror, of this great expanse of ocean which cover 70 % of Earth the blue planet. Yet the sheer size of the oceans and the difficulty of transporting across them meant the high seas were largely ignored by the vast majority of humans for centuries. Humans were largely confined to land with the only interest in the seas being as trade routes and the defence of the land. In fact all the way up to the last quarter of the twentieth century a nations territorial sea extended only three nautical miles off shore the distance that a cannon ball could be fired.

This almost casual relationship to the oceans changed dramatically in the 1960s and 1970s as technology played an ever icnreasing role in the exploitation of the natural resources of the seas. Fishing was made far easier by being able to use sophisticated sonar systems to detect the fish and by advanced nets and vessels. But it was probably the technological ability to first find and then extract oil and gas off shore on continental shelfs, and at increasing depths, which stimulated interest in exploiting marine resources. Dreams of other deep sea mineral resources (e.g. manganese nodules) simply fuelled interest in the oceans, not to mentino some of the pharmaceuticals that were being discovered.

The isolation and identification of new microalgal strains producing oil and carotenoid simultaneously with biofuel potential

Taxonomy and phylogeny of twenty two microalgal isolates were examined using both universal and newly designed molecular primers. Among the isolates, Scenedesmus bijugus, Coelastrella sp., Auxenochlorella protothecoides, and Chlorella sp. were particularly promising in terms of producing lipids as measured by fatty acid methyl esters (FAME) analysis and significant concentration of carotenoids. A comparative experiment showed that S. bijugus and Chlorella sp. were the most promising candidates (L(-)(1)d(-)(1), with biomass) 174.77±6.75, 169.81±5.22mg, lipids 40.14±3.31, 39.72±3.89mg, lutein 0.47, 0.36mg, and astaxanthin 0.27, 0.18mg respectively. The fatty acids produced by these microalgal isolates were mainly palmitic, stearic, oleic, linoleic, and linolenic acid. The freshwater microalgal isolate S. bijugus be the most suitable isolate for producing biodiesel and carotenoids, due to high productivity of biomass, lipids, metabolites, and its suitable fatty acid profile.

Analysis of mammalian cell proliferation and macromolecule synthesis using deuterated water and gas chromatography-mass spectrometry.

Deuterated water (²H₂O), a stable isotopic tracer, provides a convenient and reliable way to label multiple cellular biomass components (macromolecules), thus permitting the calculation of their synthesis rates. Here, we have combined ²H₂O labelling, GC-MS analysis and a novel cell fractionation method to extract multiple biomass components (DNA, protein and lipids) from the one biological sample, thus permitting the simultaneous measurement of DNA (cell proliferation), protein and lipid synthesis rates. We have used this approach to characterize the turnover rates and metabolism of a panel of mammalian cells in vitro (muscle C2C12 and colon cancer cell lines). Our data show that in actively-proliferating cells, biomass synthesis rates are strongly linked to the rate of cell division. Furthermore, in both proliferating and non-proliferating cells, it is the lipid pool that undergoes the most rapid turnover when compared to DNA and protein. Finally, our data in human colon cancer cell lines reveal a marked heterogeneity in the reliance on the de novo lipogenic pathway, with the cells being dependent on both 'self-made' and exogenously-derived fatty acid.

Underpricing of energy IPOs in Australia

The underpricing of initial public offerings (IPOs) has been discussed in the literature for over thirty years. Underpricing is the term used when the issue price of the shares of a company raising public equity capital and seeking to list on a stock exchange is below the closing price of the shares on the first day of listing. As such, underpricing theoretically allows subscribing investors the opportunity of making a return on the day of listing. The international evidence as examined in [4] and updated in [5] has documented that subscribing investors made handsome double-digit' (for example US IPOs - 15.7%, UK IPOs 12%, Turkish IPOs - 13.1 %, Greek IPOs -49.0%) or even triple-digit (for example Chinese IPOs 256.9%) statistically significant positive first day returns, on average. These studies are generally however of industrial company IPOs.

The purpose of this paper is to investigate the underpricing returns of Australian energy IPOs from January 1994 to June 2007. Two previous studies into natural resource IPOs in Australia only made fleeting mention of energy IPOs because of the small sample sizes. [3] identified 2 solid fuel IPOs and 13 oil and gas IPOs (amongst 130 other natural resource IPOs) during 1979 to 1990 and advised average underpricing returns of 106.5% and 47.3% respectively for investors subscribing to these IPOs. [2] investigated 19 energy IPOs (amongst 96 other natural resource IPOs) from 1994 to 1999 and reported an average underpricing return of 8.3%.

The sample set of 134 used in this study is significantly greater than previous Australian studies. These 134 energy IPOs raised over $1.945 billion of public equity capital from January 1994 to June 2007. [3] reports on the importance of the natural resources sectors to Australia's economy and the fact that companies working in these sectors constitute around one third of the entities listed on the Australian Stock Exchange.

This study also follows a highly influential paper in the IPO literature by [I]. They argue that the lower the uncertainty about the value of an IPO, the lower the underpricing needed to attract subscribers. Given the linkage between uncertainty and underpricing, this study seeks to identify the factors that might influence uncertainty and hence underpricing.

The study found that the mean underpricing return for these energy lPOs is 22.8% and statistically significant. The model used to investigate variables that might help explain the level of underpricing in this industry sector is also particularly useful. An important finding in the study for new issuers, underwriters and subscribing investors is that those energy IPO firms that used underwriters had substantially lower underpricing. The other finding that larger issues are likely to have lower underpricing is consistent with prior industrial company IPO studies.

Field evaluation of a suite of biomarkers in an Australian Tropical Reef Species, Stripey Seaperch (Lutjanus carponotatus) : Assessment of Produced Formation water from the Harriet A Platform

There is paucity of data regarding hydrocarbon exposure of tropical fish species inhabiting the waters near oil and gas platforms on the Northwest Shelf of Australia. A comprehensive field study assessed the exposure and potential effects associated with the produced water (PW) plume from the Harriet A production platform on the northwest shelf in a local reef species, Stripey seaperch (Lutjanus carponotatus). This field study was a continuation of an earlier pilot study which concluded that there were “warning signs” of potential biological effects on fish populations exposed to PW. A 10-day field caging study was conducted deploying 15 individual fish into 6 separate steel cages set 1-m subsurface at 3 stations in a concentration gradient moving away from the platform. A battery of biomarkers were evaluated including hepatosomatic index (HSI), total cytochrome P450, bile metabolites, CYP1A-, CYP2K- and CYP2M-like proteins, cholinesterase (ChE) activity, and histopathology of liver and gill tissues. Water column and PW effluent samples was also collected. Results confirmed that PAH metabolites in bile, CYP1A-, CYP2K-, and CYP2M-like proteins and liver histopathology provided evidence of significant exposure and effects after 10 days at the near-field site (~200 m off the Harriet A platform). Hepatosomatic index, total cytochrome P450, and ChE did not provide site-specific differences by day 10 of exposure to PW. CYP proteins were shown by principal component analysis (PCA) to be the best diagnostic tool for determining exposure and associated biological effects of PW on L. carponotatus. Using a suite of biomarkers has been widely advocated as a vital component in environmental risk assessments worldwide. This study demonstrates the usefulness of biomarkers for assessing the Harriet A PW discharge into Australian waters with broader applications for other PW discharges. This approach has merit as a valuable addition to environmental management strategies for protecting Australia’s tropical environment and its rich biodiversity.

Carbon dioxide corrosion inhibition : an overview of recent research on new inhibitor development

Since the introduction of inhibitors to the oil and gas industry in the 1940’s, corrosion inhibition has played a key role in carbon dioxide (CO2) corrosion control. Major inhibitor discoveries occurred from the late 1940's to the late 1960's, followed by the refinement of formulations and the development of improved application methods. Over the past two to three decades, although some new derivatives of existing inhibitors such as amide, amine and imidazoline have been reported, there have been few if any discoveries of new CO2 corrosion inhibitors. In recent years, the development of environmentally friendly inhibitors and the inhibition of localised corrosion have become driving forces behind new advances in corrosion inhibitor technology. Recently a rare earth metal organic compound, lanthanum 4-hydroxy cinnamate has been found to be an efficient corrosion inhibitor for mild steel in CO2 containing aqueous media. A resorcinarene acid has been found to provide effective localised corrosion inhibition by promoting a random distribution of insignificant anodic currents. The advent of advanced scanning probe techniques and an electrochemical integrated multi-electrode array have facilitated the discovery of corrosion inhibitors. This paper provides a brief overview of recent progress in this field.

Corrosion monitoring under disbonded coatings

Localized corrosion can occur under disbonded coatings threatening the safe operation of industry infrastructures such as underground oil and gas pipelines. Currently the assessment of localised corrosion under coating defects is a major technical challenge. The application of corrosion probes to monitor corrosion under disbonded coating also remains a difficulty. This paper presents a new corrosion sensor concept capable of electrochemically measuring corrosion rates under disbonded coatings on cathodically protected structures such as energy pipelines. Examples of its capabilities are illustrated with experimental data obtained in low conductivity aqueous solutions.

Studying the cathodic disbondment of coatings using electrochemical impedance spectroscopy

The disbondment of protective organic coatings is a widely reported pipeline coating failure mode in the oil and gas industry. Traditional methods of evaluating cathodic disbondment of pipeline coatings are based on visual inspection of pipeline conditions, and laboratory testing of cathodic disbondment resistance (CDR) using standard methods such as ASTM G8. Although some other laboratory-based techniques, such as scanning kelvin probe and scanning acoustic microscopy have been used to study the cathodic disbondment (CD) of coatings, these are often difficult to apply in practical testing. Over the past decade, electrochemical impedance spectroscopy (EIS) has been employed as a potential method for measuring CD. This paper reports preliminary results from an EIS study designed to characterise CD behaviour of epoxy coatings under excessive cathodic protection. EIS data correlated well with the area of disbonded coating. Analysis of EIS data can provide valuable information on the initiation and rates of CD.