Management of waste from uranium mining and milling in Australia

Australia has a long history of uranium mining. Most of the early production came from Rum Jungle in the Northern Territory and Mary Kathleen in Queensland. The second generation of uranium mines (Ranger, Nabarlek and Olympic Dam) came on line in the 1970s and 1980s at a time of increased environmental awareness and public scrutiny. The waste management practices at these mines are in accordance with best practicable technology for the uranium mining industry. This paper describes Australia's experience in managing the front end of the fuel cycle; uranium mining and ore processing.     

Neutron irradiation-induced embrittlement in type 316 and other austenitic steels and alloys

The effects of neutron irradiation on the structures, high-temperature tensile and creep-rupture properties, deformation and fracture characteristics of austenitic alloys, particularly 316 type austenitic steels, are surveyed. The mechanisms proposed to explain the observed irradiation-induced changes in properties and behaviour are reviewed and the additional work required to resolve areas of uncertainty and difference is summarised.     

Soft x-ray tomography for real-time applications: present status at Tore Supra and possible future developments

This paper is focused on the soft x-ray (SXR) tomography system setup at Tore Supra (DTOMOX) and the recent developments made to automatically get precise information about plasma features from inverted data. The first part describes the main aspects of the tomographic inversion optimization process. Several observations are made using this new tool and a set of shape factors is defined to help characterizing the emissivity field in a real-time perspective. The second part presents a detailed off-line analysis comparing the positions of the magnetic axis obtained from a magnetic equilibrium solver, and the maximum of the reconstructed emissivity field for ohmic and heated pulses. A systematic discrepancy of about 5 cm is found in both cases and it is shown that this discrepancy increases during sawtooth crashes. Finally, evidence of radially localized tungsten accumulation with an in-out asymmetry during a lower hybrid current drive pulse is provided to illustrate the DTOMOX capabilities for a precise observation of local phenomena.     

Identification of peptides in milk as a result of proteolysis at different levels of somatic cell counts using LC MALDI MS/MS detection

The somatic cell count (SCC) in milk is associated with increasing proteolytic degradation of caseins and it has been suggested that enzymes derived from somatic cells contribute to a lower yield and poorer quality of cheese. It is essential to increase the knowledge on naturally occurring milk proteinase activities to better understand how to improve the technological quality of milk. The aim of this work was to identify peptides actually present in milk as a result of proteolysis at different levels of SCC and to assign these peptides to potential responsible proteases where possible. Peptide fractions were prepared from acid whey by ultrafiltration at a molecular cut-off value of 10 000 Da. The peptides were separated using capillary reversed phase high performance liquid chromatography (RP-HPLC) and identified by matrix-assisted laser desorption/ionization-time of flight tandem mass spectrometry (MALDI-TOF MS/MS). Peptides identified ranged in mass from 1023 to 2000 Da, and originated from alphaS1-, alphaS2- or beta-casein. Possible responsible proteases that could be suggested when examining the peptide cleavage sites included plasmin, cathepsin B, D and leukocyte elastase. The results indicated that plasmin was primarily responsible for the observed proteolysis in milk at low cell count, whereas the cathepsins and elastase became implicated at elevated cell count. Specificity and activity of cathepsins and elastase has earlier mainly been studied in model systems, whereas less is known about their activities in milk itself. This is also the first indication of involvement of elastase in milk proteolysis through the unequivocal determination of cleavage sites.     

Cysteine protease activity in bovine milk

Proteolytic activity of native cysteine proteases was studied in bovine milk. Five fractions (fI–fV) with cysteine protease activity were separated from acid whey prepared from raw bovine milk by ion-exchange chromatography on Q-Sepharose. The hydrolytic action of the most active fractions (fIII and fV), after further purification using gel permeation chromatography on Superdex S75, was studied against individual caseins. The two fractions contained different cysteine protease activities capable of hydrolyzing both α_s1- and β-casein. Studies of the effects of different reagents on the activity of partially purified fIII showed that the activity in this fraction was unaffected by aprotinin, slightly inhibited by p-chloromercuribenzoate and o-phenanthroline and completely inhibited by -trans-epoxysuccinyl- -leucylamido (4-guanidino) butane, consistent with identification as a cysteine protease. Phenylmethylsulphonyl fluoride and pepstatin A reduced activity of fIII by 40% and 50%, respectively. The partially purified fIII retained 20% of its cysteine protease activity after heating at 55°C, 60°C, 65°C and 72°C for 40 min, 20 min, 10 min and 30 s, respectively. Immunoblotting of fIII with antibodies to the bovine lysosomal cysteine protease, cathepsin B, clearly indicated the presence of immunoreactive cathepsin B in this fraction. This study presents strong evidence for the presence of a heterogeneous group of cysteine proteases in bovine milk, with one of these enzymes probably being cathepsin B.     

Modelling the impacts of electric vehicle recharging on the Western Australian electricity supply system

This study investigates the potential impacts of EVs on the Western Australian electricity grid, the constraints on the system’s capacity to supply electricity for EV recharging and the options for managing those potential impacts and constraints. Western Australia is geographically isolated and the electricity network has no interconnection with neighbouring regions. The State energy and vehicle markets are independent of issues occurring in neighbouring states. Western Australia is a relatively clean sample space. This study eliminates uncertainty in vehicle adoption rates from analysis by assuming that all new vehicles are EVs. This gives a worst case scenario in terms of load growth and shows that it will over 200,000 EVs, which represents 10% of the fleet, before there is any significant impact on peak demand even if charging behaviours are left unfettered. The study also shows, however, that the electricity supply and transmission industry can achieve significant short- and long-term benefits if vehicle charging behaviours are managed from the outset, through, for example, demand management or structured tariffs. In the short-term, providing incentive for off-peak recharging increases utilisation of existing transmission capacity, and cheaper, more efficient base-load generation infrastructure. In the long-term, investment in more underutilised capacity can be avoided.     

The Good,the Bad,and the Expert: How Consumer Expertise Affects Review Valence Effects on Purchase Intentions in Online Product Reviews

This study aims to shed more light on the question whether, and under what circumstances, valence affects consumers' intention to buy a product after reading an online review. We hypothesize that receiver expertise could possibly moderate (a) the impact of review valence on consumers' purchase intentions, and (b) the asymmetric effects of positive and negative reviews. To test these hypotheses, we conducted an experiment, exposing participants (n = 470) to reviews varying in valence (i.e., positive, neutral, negative), with purchase‐intention as the dependent variable. The results support the moderating role of receiver expertise for both the influence and weight of review valence effects. This explains the inconsistent results for review valence reported in previous studies.