Engineering

Publication Search Results

Now showing 1 - 10 of 85
  • (2008) Song, Dengyuan; Cho, E.-C; Conibeer, Gavin; Huang, Yidan; Flynn, Christopher; Green, Martin
    Journal Article
    Amorphous Si1-xCx /SiC multilayer films were prepared by alternating deposition of Si-rich Si1-xCx and near-stoichiometric SiC layers by using magnetron sputtering. The as-deposited films were annealed at different temperatures Ta from 800 to 1100 oC. The influence of Ta and Si content in the Si-rich layer on the layered structural stability and on the formation of Si and/or SiC nanocrystals NCs is investigated by a variety of analytical techniques, including x-ray reflectivity XRR, x-ray diffraction XRD, transmission electron microscopy TEM, Raman spectroscopy, and Fourier transform infrared spectrometry FTIR. XRR showed that Si1-xCx /SiC multilayers annealed at temperatures of up to 800 oC retain their layered structure. XRD revealed that Si NCs were formed in samples with a high Si content in the Si-rich layer for Ta 800 oC. At annealing temperatures of 900 oC or greater, the formation of Si NCs was accompanied by the formation of -SiC NCs. Additionally, the formation of Si and SiC NCs was confirmed by TEM imaging and Raman spectroscopy. The Si-NC size obtained from the TEM micrographs is within the range of 3-5 nm. The -SiC NCs are smaller 2-3 nm than Si NCs. Raman analysis identified an 9 cm-1 Raman peak shift in the Si-NC peak to a lower energy with respect to that for bulk Si. FTIR Si-C bond absorption spectra exhibited narrowing of the full width at half maximum and a peak shift toward a higher wave number with increasing Ta. This behavior can be explained by an increase in order as well as an increase in the number of Si-C bonds.

  • (2008) Ho, Minh; Allinson, G; Wiley, Dianne
    Journal Article
    Studies of CO2 capture using membrane technology from coal-fired power-plant flue gas typically assume compression of the feed to achieve a driving force across the membrane. The high CO2 capture cost of these systems reflects the need to compress the low-pressure feed gas (1 bar) and the low CO2 purity of the product stream. This article investigates how costs for CO2 capture using membranes can be reduced by operating under vacuum conditions. The flue gas is pressurized to 1.5 bar, whereas the permeate stream is at 0.08 bar. Under these operating conditions, the capture cost is U.S. $54/tonne CO2 avoided compared to U.S. $82/ tonne CO2 avoided using, membrane processes with a pressurized feed. This is a reduction of 35%. The article also investigates the effect on the capture cost of improvements in CO2 permeability and selectivity. The results show that the capture cost can be reduced to less than U.S. $25/tonne CO2 avoided when the CO2 permeability is 300 barrer, CO2/N2 selectivity is 250, and the membrane cost is U.S. $10/m2.

  • (2008) Wakefield, Claire; Meiser, Bettina; Gaff, C; Barratt, Anthony; Patel, Minoo; Suthers, G; Lobb, Elizabeth; Ramsay, J; Mann, G
    Journal Article
    Purpose: Despite the established importance of the role of family history in prostate cancer, relatively little research encompasses the psychosocial issues relevant to unaffected men with a family history of prostate cancer. To determine the completeness and quality of available literature on the issues faced by men with a high risk of prostate cancer, we conducted a multidisciplinary review of the literature to provide some guidance on the information that clinicians might provide to men who are concerned about family history. Materials and Methods: A structured literature search was conducted by a multidisciplinary team of clinicians and researchers who reviewed the medical and psychosocial literature, and identified 21 relevant studies. Results: Research suggests that many high risk patients are concerned about the risk of prostate cancer, and some may significantly overestimate that risk. Several studies have shown high screening rates among high risk patients and high levels of interest in genetic testing for prostate cancer risk should it become available, yet many men also report a desire for more information about their personal risk and risk management options. Conclusions: Given the lack of clear data on the efficacy of prostate cancer screening among high risk patients, clinicians could consider providing men who are concerned about family history with information on their personal risk, help them to clarify the potential benefits, limitations and harms of prostate cancer screening in their situation, and then support their choice regarding the management of prostate cancer risk.

  • (2008) Kasparian, Nadine; Meiser, Bettina; Butow, P; Simpson, John; Mann, G
    Journal Article
    Despite rapid advancements in molecular genetics research, little is known about the psychological experiences of individuals with a family history of melanoma. The present study aimed to identify factors contributing to psychological distress among affected and unaffected individuals with a strong family history of melanoma. A total of 121 adults who had recently been informed of the identification of a family-specific mutation in the CDKN2A melanoma susceptibility gene, completed a self-report questionnaire assessing cancer-specific and generalized distress, and a variety of potential predictors. Having a personal history of melanoma (OR = 3.37, p = 0.033), perceiving greater family implications of melanoma (OR = 2.52, p < 0.0001), and the tendency to monitor for threatening information (OR = 3.12, p = 0.008) were associated with melanoma-specific distress. Being childless (beta = 2.09, p = 0.007), perceiving sun exposure as an important cause of melanoma (beta = 1.15, p = 0.015), and perceiving greater family implications of melanoma (beta = 1.02, p = 0.002) were associated with greater generalized anxiety, while monitoring moderated the relationship between endorsement of a genetic model of melanoma and generalized anxiety (p = 0.005). As in other common familial cancers, distress was relatively uncommon in this familial melanoma cohort, even after notification of the presence of a family mutation. Participants do not contemplate their melanoma risk in isolation, but evaluate their risk vis-a-vis the experiences of their relatives.

  • (2008) Meiser, Bettina; Kasparian, Nadine; Mitchell, Penny; Strong, Kathryn; Simpson, John; Tabassum, Laila; Mireskandari, Shab; Schofield, Peter
    Journal Article
    Objectives: This study assesses interest in genetic testing for gene variations associated with bipolar disorder and associated information needs. Methods: Two hundred individuals (95 unaffected and 105 affected with either bipolar disorder, schizoaffective disorder-manic type, or recurrent major depression) from families with multiple cases of bipolar disorder were assessed, using mailed, self-administered questionnaires. Results: The percentage of participants reporting interest in genetic testing was associated with the degree of certainty with which any test would indicate the development of bipolar disorder. Interest in genetic testing, given a 25% lifetime risk scenario, was lowest (with 77% of participants indicating interest), and highest for the 100% lifetime risk scenario (92%). Eighty percent of participants indicated interest in genetic testing of their own children; of these 30% reported wanting their children tested at birth, and 33% in early childhood. Forty-one percent of participants reported that they would be interested in preimplantation genetic diagnosis, and 54% in prenatal testing. Limitations: The possibility of ascertainment bias cannot be ruled out. Interest in hypothetical genetic testing for bipolar disorder may not necessarily translate into actual utilization. Conclusions: These results indicate that uptake of genetic testing for genotyping for low-risk alleles related to bipolar disorder is likely to be lower than for testing for high-penetrance gene mutations that follow Mendelian inheritance. The discrepancy between the desired age of testing children and the accepted current practice may be a source of distress and conflict for parents and health professionals alike.

  • (2008) Fei, W; Shui, G; Gaeta, Bruno; Du, Xi; Kuerschner, L; Brown, Andrew; Wenk, M; Parton, R; Yang, Hyuk-Seung; Li, Peng
    Journal Article
    Lipid droplets (LDs) are emerging cellular organelles that are of crucial importance in cell biology and human diseases. In this study, we present our screen of 4,700 Saccharomyces cerevisiae mutants for abnormalities in the number and morphology of LDs; we identify 17 fld (few LDs) and 116 mld (many LDs) mutants. One of the fld mutants (fld1) is caused by the deletion of YLR404W, a previously uncharacterized open reading frame. Cells lacking FLD1 contain strikingly enlarged (supersized) LDs, and LDs from fld1 Delta cells demonstrate significantly enhanced fusion activities both in vivo and in vitro. Interestingly, the expression of human seipin, whose mutant forms are associated with Berardinelli-Seip congenital lipodystrophy and motoneuron disorders, rescues LD-associated defects in fld1 Delta cells. Lipid profiling reveals alterations in acyl chain compositions of major phospholipids in fld1 Delta cells. These results suggest that an evolutionally conserved function of seipin in phospholipid metabolism and LD formation may be functionally important in human adipogenesis.

  • (2008) Peters, G
    Journal Article
    Creating meaningful active learning experiences can be a significant and sometimes comical challenge for a new lecturer. In this article, I describe my own active learning experience as I attempted to break down the separation between tutorials and lectures that was typical of the university education I experienced. The adoption of a sustainability framework for decision-making processes associated with major infrastructure developments in the Australia water industry is a recent innovation which has provided a convenient vehicle for supporting this change. A case study drawn from a fourth year Environmental Engineering Practice class is used to illustrate how the framework can be applied to provide new and relevant curriculum. The overall intent of this paper is to support new lecturers on their own journeys into teaching, and perhaps to remind their experienced mentors of a particular challenge their colleagues face at the beginning.

  • (2008) Peters, G; Sack, F; Lenzen, M; Lundie, S; Gallego, B
    Journal Article
    A revised methodology for calculating ecological footprints is proposed. The method considers anthropogenic disturbances at a finer level of geographical desegregation than previous methods; instead of a single national land area it considers 1408 smaller regions within Australia. It also addresses a previous gap in disturbance based ecological footprint calculation, that is, the exclusion of ecotoxic emissions. The method is described and illustrated using a case study. The resulting ecological footprint is larger than previous calculations, but it avoids a current methodological problem in which the energy used to treat exhaust gases or wastewaters increases the ecological footprint of communities without any corresponding benefit associated with reduced emissions to the environment.

  • (2008) Khan, Stuart; Roser, David; Davies, Cheryl; Peters, G; Stuetz, Richard; Tucker, Robyn; Ashbolt, Nicholas
    Journal Article
    Commercial feedlots for beef cattle finishing are potential sources of a range of trace chemicals which have human health or environmental significance. To ensure adequate protection of human and environmental health from exposure to these chemicals, the application of effective manure and effluent management practices is warranted. The Australian meat and livestock industry has adopted a proactive approach to the identification of best management practices. Accordingly, this review was undertaken to identify key chemical species that may require consideration in the development of guidelines for feedlot manure and effluent management practices in Australia. Important classes of trace chemicals identified include steroidal hormones, antibiotics, ectoparasiticides, mycotoxins, heavy metals and dioxins. These are described in terms of their likely sources, expected concentrations and public health or environmental significance based on international data and research. Androgenic hormones such as testosterone and trenbolone are significantly active in feedlot wastes, but they are poorly understood in terms of fate and environmental implications. The careful management of residues of antibiotics including virginiamycin, tylosin and oxytetracycline appears prudent in terms of minimising the risk of potential public health impacts from resistant strains of bacteria. Good management of ectoparasiticides including synthetic pyrethroids, macrocyclic lactones, fluazuron, and amitraz is important for the prevention of potential ecological implications, particularly towards dung beetles. Very few of these individual chemical contaminants have been thoroughly investigated in terms of concentrations, effects and attenuation in Australian feedlot wastes. © 2007 Elsevier Ltd. All rights reserved.

  • (2008) Ng, Lawrence; Zarrabi, Khosrow
    Journal Article
    Abstract This paper demonstrates the application of a new multiaxial creep damage model developed by the authors to predict the failure time of components made of service aged 2.25%Cr-1%Mo, 0.5%Cr-0.5%Mo-0.25%V low alloy steels, titanium and nickel-based superalloys. The model accounts for the tertiary creep behaviour and assumes the creep damage is related to the internal energy absorbed by the material. The authors argue that the model is the most appropriate for characterizing gross creep damage from a macroscopic point of view because it takes into accounts both the multiaxial internal deformation and loading. The verification and application of the model are demonstrated by applying it to the Bridgman notched bars for which the experimental data are available. The predicted failure times by the model are compared with the experimental results and those obtained from the reference stress method. The results show that the proposed model is capable of predicting failure times of the components made of the above-mentioned materials with an accuracy of 2.2% or better. Also, it is shown that the model predicts the creep failure times of the components more accurately than the reference stress method.