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Passing bays in an underground mine
No full textSome mining companies are investigating the use of road trains to increase productivity in underground mines. Road trains require dedicated passing bays in declines. The spacing of these passing bays can have a significant impact on haulage productivity. This technical note describes the use of simulation to find the optimal spacing. If the distance between passing bays is sufficiently small then descending trains can be interleaved with ascending trains, which increases productivity. If the spacing is too small, however, productivity can decrease as descending trains wait in passing bays for ascending trains. For a real mine the spacing should be less than the theoretical critical distance to cope with variations in loading and unloading durations.
Sustainable development : a solution or distraction for business?
No full textThis paper considers why, despite the concept of sustainable-development having been prominent on the international stage for well over 20 years, there is little to show by way of a transition to a sustainable-world outcome and, instead, in some ways the situation is deteriorating. The mainstream sustainable-development approach as advocated by business, and as is prominent in the political sphere, is critiqued to consider if this is itself a key problem. The paper concludes that it is as, rather than helping society achieve needed change, this approach instead creates a false sense of progress that acts as a barrier to the more decisive action that is necessary to address the underlying drivers of humanity's unsustainable behaviours. Further, the paper proposes that the very act of pursuing mainstream sustainabledevelopment makes a sustainable-world goal harder to achieve. A way forward for the business sector is proposed by it embracing a more Transformational sustainable-world approach in both its internal activities and in its advocacy in the broader public and political space.
Development of surface modification techniques for the covalent attachment of insulin-like growth factor-1 (IGF-1) on PECVD silica-coated titanium
No full textOsseointegration is a complex process governed by the interaction of many cell types including blood cells (erythrocytes, platelets and leukocytes), phagocytic cells (macrophages) and bone cells (osteoblasts and osteoclasts) on or near the implant surface. The implant surface can be modified through a variety of methods in order to achieve control of some of these cellular interactions and consequently increase the degree of implant fixation with the surrounding bone tissue. In this investigation, titanium was coated with hydroxylated silica by plasma enhanced chemical vapour deposition (PECVD) to increase the surface hydrophilicity and generate reactive surface silanol groups. Subsequently, the silica-coated titanium surface was further modified through silanisation to generate surfaces bearing different reactive chemical functionalities consisting of aldehydes, epoxides and isocyanates, which can react with the amino groups of proteins and growth factors. 2,2,2-trifluoroethylamine (FEAM) was reacted on these surfaces to determine the coupling efficiency of the different surface chemical functionalities. The amino group of FEAM can react with an amino-reactive surface functional group to form a surface terminated with 3 fluorine atoms per FEAM molecule that can be detected by X-ray photoelectron spectroscopy. By analysing the techniques used for protein attachment with the FEAM model molecule, a successful method for isocyanate/amine coupling was found and later adapted for tethering IGF-1 molecules to the functionalised PECVD silica-coated titanium surface. Therefore, this simple method of preliminary testing protein reactivity may prove to be a cost effective strategy in the development of new biomaterial surfaces modified using protein bioconjugation methods.
Molecular characterization of chromium (VI) reducing potential in Gram positive bacteria isolated from contaminated sites
No full textHexavalent chromium [Cr(VI)] is highly toxic, teratogenic and carcinogenic to man and other animals. Some bacterial species have the ability to reduce Cr(VI) to a stable speciation state of trivalent chromium [Cr(III)], which is insoluble and comparatively less toxic. Therefore, the reduction of Cr(VI) thus provides potential as a means for environmental bioremediation of Cr(VI) pollution. In the present study bacteria isolated from chromium and diesel contaminated sites were found to have the ability to rapidly reduce highly toxic concentrations of Cr(VI) to Cr(III) when grown in minimal medium supplemented with glucose as the sole carbon source. Partial chromate reductase gene sequences were retrieved after PCR amplification of genomic DNA extracted from three Gram positive isolates which were highly similar (>99% sequence similarity) to chromate reductase genes found in Gram negative bacteria, more specifically those identified from Escherichia coli and Shigella spp. whole-genome studies. The isolated bacteria were putatively identified by 16S rRNA gene sequencing as Arthrobacter aurescens strain MM10, Bacillus atrophaeus strain MM20, and Rhodococcus erythropolis strain MM30.
Consumer perceptions of eco-friendly vs. conventional wines in Australia
No full textPrevious research has extensively studied consumer perceptions of organic food, but little is known about consumer perceptions of organic wine. Moreover, most studies focus on organic products, without any comparison with other eco‐friendly products. This paper proposes to partially fill this gap by comparing consumer perceptions of conventional and different eco‐friendly wines in Australia.
Quantum dot superluminescent diodes for optical coherence tomography: skin imaging
No full textWe present a high-power (18 mW continuous wave exiting a single-mode fiber and 35 mW exiting the facet), broadband (85 nm full-width at half-maximum) quantum dot-based superluminescent diode, and apply it to a time-domain optical coherence tomography (OCT) setup. First, we test its performance with increasing optical feedback. Then we demonstrate its imaging properties on tissue-engineered (TE) skin and in vivo skin. OCT allows the tracking of epidermal development in TE skin, while the higher power source allows better sensitivity and depth penetration for imaging of in vivo skin layers.
