David Parlevliet

There are good reasons to believe that small (< 5kg), highly manoeuvrable rotorcraft may be valuable to human explorers on Mars. They could be used for scouting, aerial photography, maintenance inspection, hoisting antenna or guy wires, locating science targets and rapid transportation of small tools or regolith samples. Low atmospheric pressures and temperatures near the Martian surface present severe challenges to the design of rotorcraft. To provide sufficient lift, even allowing for lower gravitational acceleration (3.71m/s2), rotors need to be larger and turn faster than their terrestrial counterparts, thus imposing high mechanical stresses. This, combined with poor battery efficiency at low temperatures, could impose serious restrictions on the endurance of such aircraft. Extremely fine and abrasive particulate matter would also be problematic for reliable functioning of any exposed bearings, sensors and cameras. In this paper we study the use of both conventional and modified low pressure propellers for the use in a small quadrotor at low pressures. We modelled the rotors computationally and our simulations show the need for a thrust of approximately 5N per motor for a 4kg quadrotor at Mars. Blade element theory calculations have suggested that it is possible to meet these requirements. As a baseline, conventional propeller designs were tested in a vacuum chamber down to 6 mbar. As the pressure was reduced the thrust dropped significantly from approximately 6N to 0.05N. However, the power consumption also dropped from 120W to 16W due to the much lower drag on the propeller. Tests on propellers based on our simulations also demonstrated a decrease in thrust. While this system is not yet optimised, it demonstrated only a 60% decrease in thrust which compares favourably with conventional propellers, with a 40% reduction in power consumption. This suggests that correctly optimised propellers may indeed be able to be used as propulsion for lightweight multirotor aircraft on Mars. Since our vacuum chamber tests are complicated by ground effects and limited freedom to move, we intend to drop a 4kg automated test vehicle from a balloon at 120,000 feet, where atmospheric conditions approximate those at Mars, and record performance data onboard during programmed manoeuvres. The decent of the rotorcraft could also be used to correct the results for the greater acceleration due to gravity near Earth.

Solar Photovoltaic (PV) system installations are enjoying a continued and remarkable growth in Australia. Currently there are over a million PV systems installed in the country with an installed capacity of over 3.5GW, the majority of which are small grid-connected rooftop systems of less than 10kW capacity. Australian conditions can be very harsh, contributing to early equipment failure rates, while installation of small systems can be suboptimal,and often without monitoring. Documentation of faults with PV products and installations in Australia is limited and there is little publically available information in regards to the types of problems that occur, where and why they occur, how frequently and if they are an ongoing issue. The reliability of PV systems is a strong determinant of cost effectiveness, and critical to continued investor confidence. A ‘PV Module and System Fault Reporting Portal’ (PVFRP) has been developed to increase the understanding of the PV industry and other stakeholders about the types of problems that are found with different system components in the Australian environment. The PVFRP contains a survey to collect data from owners, operators, installers and inspectors of PV system who have detected a fault/problem with whole or part of a system. Analysis and dissemination of the Portal data will help to improve future PV system design, component selection, product development and product approvals for Australian conditions. The survey is available at: www.surveymonkey.com/s/pvwebportal. This paper presents the initial findings of the survey after five months of operation. The number of responses received thus far is not large enough to reach to any substantive conclusions, however, they are in agreement with the research outputs achieved elsewhere. This information will help the industry address the challenges that PV systems, components and related service delivery are facing in Australia. The information presented here will be updated as more data become available and will be published on a regular basis.

With the advent of the Tertiary Education Quality and Standards Agency (TEQSA) there is an increased focus, at all levels in the university community, on the quality of teaching, learning and research. Quality itself is not well defined within the framework of TEQSA, the definition is however approximated by a set of minimum standards. This is problematical as there is scant evidence that threshold standards produce a high quality education. Often the good quality, and high standards, that are achieved within the university are due to the good quality, and high personal standards, of the staff. The appraisal of quality is therefore left to a number of stakeholders, within the University community, and with external course accreditation bodies. This means that individual unit coordinators, and members of the University community, have to amass a large collection of disparate material to create the body of evidence for compliance with standards, and to act as quality indicators. Managing this information can be very time consuming at the individual level. It is therefore essential that there be streamlined methods for enabling compliance and capturing and storing the evidence.

Traditionally students would turn up at the first Physics lecture of the semester, be given a Study Guide and told to purchase a text book and laboratory manual. They would then be well equipped to work their way through the unit. There were perhaps one or two students that could not manage to get to a laboratory session and allowances were made for them to catch up during non-teaching weeks. Some even moved out of commuting distance, missed out on lectures and had to complete a residency for their laboratory work. This made studying more complicated for both the students and the unit coordinator. It also disadvantaged country students and working students who were studying part time. Over the years Murdoch University Physics as strived to address this situation, and a structure has evolved that facilitates the learning of students who cannot attend the campus. These students are said to be studying in the external mode.

Silicon nanowires of high density and high aspect ratio similar to those shown in the literature (Niu et al., 2004, Hofman et al., 2003) have been grown using a variation of plasma enhanced chemical vapour deposition (PECVD) known as pulsed plasma enhanced chemical vapour deposition (PPECVD) using a range of different modulation frequencies. For the range of frequencies used it was found that the presence of modulated silane plasma increases the average density and sample coverage of silicon nanowires. Both of these effects are proposed as being due to the increase in the number of times the plasma is struck and turned off during the deposition process. For low temperature growth of silicon nanowires the presence of pulsed silane plasma improves the density and sample coverage of silicon nanowires.