The limited role for Carbon Capture and Storage (CCS) technologies in a sustainable Australian energy future

There is considerable debate regarding the potential role of Carbon Capture and Storage (CCS) technologies in reducing Australia's greenhouse emissions. The latest climate change science suggests that major (60% or more by 2050), rapid (peaking within 20 years) cuts in global emissions may be required to avoid dangerous climate change. There are a number of existing abatement options including energy efficiency, various renewable energy technologies, nuclear power and fuel switching to natural gas; as well as emerging options including CCS. We outline a simple technology assessment framework for policymakers to evaluate these different options given the climate change imperative. This framework includes technology status, delivered energy services, present and possible future costs, potential scale of abatement, potential speed of deployment and other possible social outcomes. Application of this framework to CCS suggests that it should be considered as a promising, but still somewhat unproven, option that potentially offers very significant abatement potential and good integration into the existing energy industry. There are, however, some outstanding questions regarding its effectiveness and safety, its abatement is likely to come at significant cost, and it is unlikely to be able to make a significant contribution for well over a decade. The Australian policy implications are that while government support for R&D and Demonstration of CCS is appropriate and should in our view be expanded, the major priority should be to support greater deployment of existing abatement options including energy efficiency, efficient gas-fired generation and cogeneration and renewable energy. Such policy support is noticeably lacking at present.     

Aeration and gutter water levels in siphonic roof drainage systems

An investigation is presented into how negative system pressures, the degree of aeration, and gutter water levels are affected by the number of outlets in a siphonic roof drainage system. The experimental results show that system pressures decrease if outlets are blocked. It is also shown that the depth of water above an outlet is strongly influenced by the negative pressure acting at the outlet. As the suction effect at the outlet increases, due to lower system pressures, more water and air will be drawn into the outlets and this will result in a corresponding increase in overall gutter water depth. The results also show that there is often built-in redundancy in multiple outlet siphonic systems experiencing lower-intensity rainfall events, and if one or two outlets were blocked, the system would still operate satisfactorily. A new outlet suppressor was trialled and this was shown to reduce gutter water levels by up to 58% at some positions in the gutter.

Il est présenté une enquête sur la manière dont les pressions négatives dans le système concerné, le degré d'aération et les niveaux d'eau dans les chéneaux sont affectés par le nombre d'orifices de sortie dans un système d'écoulement des eaux de toit par siphonnage. Les résultats expérimentaux montrent que les pressions dans le système diminuent si des orifices de sortie sont obturés. Il est également montré que la profondeur de l'eau au-dessus d'un orifice de sortie est fortement influencée par la pression négative s'exerçant à l'orifice de sortie. Plus l'effet de succion à l'orifice de sortie augmente, en raison des pressions plus faibles dans le système, et plus les quantités d'air et d'eau entraînées dans les orifices de sortie seront importantes, et cela aura pour résultat une augmentation correspondante de la profondeur générale de l'eau dans les chéneaux. Les résultats montrent également qu'il existe souvent une redondance intégrée dans les systèmes à siphons comportant des orifices de sortie multiples et soumis à des épisodes pluvieux de faible intensité, et que si un ou deux orifices de sortie sont obturés, le système fonctionne encore de manière satisfaisante. Un nouvel obturateur d'orifice de sortie a été essayé, ce qui a permis de montrer que celui-ci réduit dans une proportion allant jusqu'à 58 % en certains points les niveaux d'eau dans les chéneaux.

Mots clés: aération, niveaux d'eau dans les chéneaux, pressions négatives, écoulement des eaux de toit par siphonnage     

Numerical experience with diagonalization algorithms for asymmetric demand traffic assignment

This paper reviews the concept of a diagonalization algorithm for use in solving traffic network equilibrium problems for which the arc cost and/or the origin-destination travel demand functions are asymmetric. Such functions are known to occur in realistic settings involving multiple modes or users. The computational performance of this algorithm for different degrees of travel demand asymmetry is then explored by a detailed numerical experiment since no previous results of this type have been reported. It is found that, through the use of progressive stopping tolerances, the impact of high degrees of travel demand function asymmetry on the computational burden associated with finding a traffic network equilibrium may be mitigated; in effect equilibrium problems with high degrees of demand asymmetry are little more difficult to solve than perfectly symmetric problems.     

Development of Simplified Heterocyclic Acetogenin Analogues as Potent and Selective Trypanosoma brucei Inhibitors

Neglected tropical diseases caused by parasitic infections are an ongoing and increasing concern. They are a burden to human and animal health, having the most devastating effect on the world′s poorest countries. Building upon our previously reported triazole analogues, in this study we describe the synthesis and biological testing of other novel heterocyclic acetogenin‐inspired derivatives, namely 3,5‐isoxazoles, furoxans, and furazans. Several of these compounds maintain low‐micromolar levels of inhibition against Trypanosoma brucei, whilst having no observable inhibitory effect on mammalian cells, leading to the possibility of novel lead compounds for selective treatment.     

The FKBP5 Gene Affects Alcohol Drinking in Knockout Mice and Is Implicated in Alcohol Drinking in Humans

FKBP5 encodes FK506-binding protein 5, a glucocorticoid receptor (GR)-binding protein implicated in various psychiatric disorders and alcohol withdrawal severity. The purpose of this study is to characterize alcohol preference and related phenotypes in Fkbp5 knockout (KO) mice and to examine the role of FKBP5 in human alcohol consumption. The following experiments were performed to characterize Fkpb5 KO mice. (1) Fkbp5 KO and wild-type (WT) EtOH consumption was tested using a two-bottle choice paradigm; (2) The EtOH elimination rate was measured after intraperitoneal (IP) injection of 2.0 g/kg EtOH; (3) Blood alcohol concentration (BAC) was measured after 3 h limited access of alcohol; (4) Brain region expression of Fkbp5 was identified using LacZ staining; (5) Baseline corticosterone (CORT) was assessed. Additionally, two SNPs, rs1360780 (C/T) and rs3800373 (T/G), were selected to study the association of FKBP5 with alcohol consumption in humans. Participants were college students (n = 1162) from 21–26 years of age with Chinese, Korean or Caucasian ethnicity. The results, compared to WT mice, for KO mice exhibited an increase in alcohol consumption that was not due to differences in taste sensitivity or alcohol metabolism. Higher BAC was found in KO mice after 3 h of EtOH access. Fkbp5 was highly expressed in brain regions involved in the regulation of the stress response, such as the hippocampus, amygdala, dorsal raphe and locus coeruleus. Both genotypes exhibited similar basal levels of plasma corticosterone (CORT). Finally, single nucleotide polymorphisms (SNPs) in FKBP5 were found to be associated with alcohol drinking in humans. These results suggest that the association between FKBP5 and alcohol consumption is conserved in both mice and humans.     

The processing of fiber reinforced thermoplastics using co-rotating twin screw extruders

For short fiber reinforced thermoplastics the effect of fiber length and the fiber/matrix bond on the ultimate properties of the material are well understood. But, how the process conditions under which the composite is made affect the fiber length and the fiber matrix bond has not been so thoroughly reported in the literature. A study of this relationship has been made on a co-rotating twin screw extruder incorporating 30 percent by weight of glass fiber into nylon 66 to make the composite. Experimental results are presented to show how machine variables such as mixing configuration and screw speed affect the material properties and process efficiency. The properties of the composite were assessed by measurement of the fiber length distribution and tensile strength. From the results in the text it is possible to select machine variables to give desired production conditions. Although most of the work concerns the twin screw extruder, some of the consequences of subsequent injection molding are also shown.     

Fatty acid and sugar composition of avocado,cv. Hass,in response to treatment with an ethylene scavenger or 1-methylcyclopropene to extend storage life

This study reports on the effect of 1-methylcyclopropene (1-MCP) and a newly developed palladium (Pd)-promoted ethylene scavenger (e + ® Ethylene Remover) on changes in firmness, colour, fatty acids and sugar content of early and late season avocado (Persea americana Mill.), cv. Hass, during storage at 5 °C and subsequent ripening at 20 °C. The e + ® Ethylene Remover effectively delayed ripening of avocado stored at 5 °C. 1-MCP was more effective at inhibiting ripening, but, in contrast to e + ® Ethylene Remover, it impaired subsequent ripening. Fatty acid profile of late season fruit remained unchanged in response to treatments or storage time, whilst that of early season fruit was slightly, yet significantly, different according to treatments and storage time. Substantial amounts of perseitol were found in all fruit. In contrast, mannoheptulose was only present at high concentration in early season fruit whilst it was quasi-absent in late season fruit. Where ripening was inhibited in response to 1-MCP treatment, significantly more mannoheptulose and better maintenance of perseitol was found vs. controls. Similarly, but to a lesser extent and concomitant with trends in firmness retention and colour changes, e + ® Ethylene Remover led to greater maintenance of mannoheptulose and perseitol than that of controls. This is the first piece of research comparing effects of ethylene removal vs. ethylene action blocking on physical and biochemical changes in avocado cv. Hass and supports the view that C7 sugar metabolism could be an important feature of the avocado fruit-ripening process.     

Elevated-Temperature-Delayed Failure of Alumina Reinforced with 20 vol% Silicon Carbide Whiskers

Alumina composites reinforced with 20 vol% SiC whiskers were exposed to applied stresses in four-point flexure at temperatures of 1000°, 1100°, and 1200°C in air for periods of up to 14 weeks. At 1000° and 1100°C, an "apparent" fatigue limit was established at stresses of ∼ 75% of the fast fracture strength. However, after long-term (>6 weeks) tests at 1100°C, some evidence of crack generation as a result of creep cavitation was detected. At 1200°C applied stresses as low as 38% of the 1200°C fracture strength were sufficient to promote creep deformation and accompanying cavitation and crack generation and growth resulting in failures in times of <250 h.     

Filtration in coal liquefaction: preparation of filter aid from filter cake

In this study the preparation of filter aid from filter cake is considered. Two methods of preparation, carbonization at 550–600 °C and combustion at 800–1000 °C, are used and the optimum conditions determined. The performance of the products is assessed as both a precoat and body feed by comparison with a commercial grade of diatomite. It is shown that efficient filter aids, with performances comparable to that of diatomite, may be produced from filter cake.