2,007 research outputs found

    Crack propagation in light alloys Ministry of Aviation contract no. PD/28/07

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    The revised approach to the measurement of the rate of crack propagation in light alloys has entailed the development of new experimental techniques, in particular the development of a multi-channel interval timer. The design of this instrument and descriptions of the new techniques are reported here together with the results of some preliminary evaluation tests

    Stress redistribution due to creep in nimonic 90 ministry of aviation contract no. PD/28/021 report for the period January 1964 - June 1965: part 1

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    The period covered by this report has been devoted to the design, construction development and calibration of a special apparatus to simulate the stress redistribution conditions occurring during the creep of a cooled turbine blade. The experimental assembly consists of two creep machines, each operating at a different temperature, so controlled that a load is shared between them. maintaining equal creep strains (and in consequence equal creep rates) in each specimen. The stress in each specimen and the creep strain of the pair are automatically measured and recorded by a specially developed unit. Some preliminary results on an aluminium alloy are presented

    Irradiation effect at cryogenic temperature on tensile properties of titanium and titanium- base alloys

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    Irradiation effects on tensile behavior of titanium alloys and titanium at cryogenic temperature

    Wetland-based passive treatment systems for gold ore processing effluents containing residual cyanide, metals and nitrogen species

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    Gold extraction operations generate a variety of wastes requiring responsible disposal in compliance with current environmental regulations. During recent decades, increased emphasis has been placed on effluent control and treatment, in order to avoid the threat to the environment posed by toxic constituents. In many modern gold mining and ore processing operations, cyanide species are of most immediate concern. Given that natural degradation processes are known to reduce the toxicity of cyanide over time, trials have been made at laboratory and field scales into the feasibility of using wetland-based passive systems as low-cost and environmentally friendly methods for long-term treatment of leachates from closed gold mine tailing disposal facilities. Laboratory experiments on discrete aerobic and anaerobic treatment units supported the development of design parameters for the construction of a field-scale passive system at a gold mine site in northern Spain. An in situ pilot-scale wetland treatment system was designed, constructed and monitored over a nine-month period. Overall, the results suggest that compost-based constructed wetlands are capable of detoxifying cyanidation effluents, removing about 21.6% of dissolved cyanide and 98% of Cu, as well as nitrite and nitrate. Wetland-based passive systems can therefore be considered as a viable technology for removal of residual concentrations of cyanide from leachates emanating from closed gold mine tailing disposal facilities

    Deep, ultra-high-resolution radio imaging of submillimetre galaxies using Very Long Baseline Interferometry

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    We present continent-scale VLBI - obtained with the European VLBI Network (EVN) at a wavelength of 18cm - of six distant, luminous submm-selected galaxies (SMGs). Our images have a synthesized beam width of ~30 milliarcsec FWHM - three orders of magnitude smaller in area than the highest resolution VLA imaging at this wavelength - and are capable of separating radio emission from ultra-compact radio cores (associated with active super-massive black holes - SMBHs) from that due to starburst activity. Despite targeting compact sources - as judged by earlier observations with the VLA and MERLIN - we identify ultra-compact cores in only two of our targets. This suggests that the radio emission from SMGs is produced primarily on larger scales than those probed by the EVN, and therefore is generated by star formation rather than an AGN - a result consistent with other methods used to identify the presence of SMBHs in these systems.Comment: MNRAS, in pres

    The replica strain gauge technique

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    Surface deterioration and dimensional stability tests have been carried out on the low melting point replication alloy described in the first report. A range of alloys for the replication of surfaces at temperatures in the range 120 - 150°C has been prepared and evaluated. Preliminary studies of a cold pressing technique using fully annealed commercial purity aluminium as the replication material have shown that the technique has considerable promise for application over a wide range of temperatures

    The multi-level perspective analysis: Indonesia geothermal energy transition study

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    The study adopts a multi-level perspective in technology transition to analyse how the transition process in the development of geothermal energy in Indonesia is able to compete against the incumbent fossil-fuelled energy sources. Three levels of multi-level perspective are socio-technical landscape (ST-landscape), socio-technical regime (ST-regime) and niche innovations in Indonesia geothermal development. The identification, mapping and analysis of the dynamic relationship between each level are the important pillars of the multi-level perspective framework. The analysis considers the set of rules, actors and controversies that may arise in the technological transition process. The identified geothermal resource risks are the basis of the emerging geothermal technological innovations in Indonesian geothermal. The analysis of this study reveals the transition pathway, which yields a forecast for the Indonesian geothermal technology transition in the form of scenarios and probable impacts

    Teaching Professional Communication in a Global Context: Using a Three-Phase Approach of Theory Exploration, Self-Assessment, and Virtual Simulation

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    In today\u27s globally diverse society, standard theoretical instruction is not able to expose our students to the realities of international communication, multicultural collaboration, and dispersed global work. Abstract text-based cases are limited in delivering a realistic view of the challenges of working virtually and globally within international teams. In addition to cases, we believe that hands-on experiential, collaborative exercises – combined with the metacognitive exercise of reflective practice – offer greater learning potential. While international collaboration and exercises may take extra time, effort, and cost, the benefits to students can be substantial