Impacts of DG penetration in the Bamaga and Gununa isolated distribution networks

Isolated distribution systems are dispersed throughout regional Queensland to supply small isolated communities that are distant from the main supply grid. The costs of maintaining the electricity supply to these areas is costly; mainly due to the cost of diesel fuel. Furthermore, there is a community focus on climate change, and Ergon Energy aims to reduce the reliance on fossil fuels whilst optimising cost efficiencies and greenhouse gas emissions. The objective of this study is to examine the impacts of renewable energy sources in isolated power systems. For the locations studied, viable renewable energy sources have been integrated into these networks. Anticipated challenges and issues with the integration of the intermittent renewable energy sources were addressed, using mitigation techniques, including energy storage solutions. The investigation and findings demonstrated that network improvements can be achieved by an ideal level of renewable penetration, which has been the main focus of the project. The project involved the development and simulation of MATLAB Simulink and SINCAL models of the two isolated networks at Gununa and Bamaga. The subsequent analysis of these systems has shown a modest penetration level of renewables can be combined with energy storage solutions, which reduces fuel consumption and greenhouse gas emissions at these locations.

Impact of high wind penetration on the voltage profile of distribution systems

In this paper, simulation results showing the effect of lower and higher penetration of distributed wind generation on the voltage profile in distribution systems have been presented. The analysis is carried out over two distribution test systems. The detailed mathematical modeling of the system is also presented. It also investigates the small-signal stability of distribution systems using eigenvalue approach. The analyses show that voltage variation problems occur in different nodes of the distribution networks with an increase of penetration level. However, proper selection of dispersion level can improve the voltage profile of the distribution systems

Impact of high PV penetration into distribution networks under contingencies

This paper analyzes the static voltage stability of distribution networks with photovoltaic (PV) generators under contingencies. The analysis is carried out on a widely used 16-bus test system. The paper treats the Q-V characteristics of the distribution grid for various PV penetration levels. Simulation results show that a higher penetration of PV increases the static coltage stability of the system. However, the tripping of multiple PV generators due to external disturbances, overloading and loss of distribution lines reduces the voltage stability margin of the system.

Superior performance of aptamer in tumor penetration over antibody : implication of aptamer-based theranostics in solid tumors

Insufficient penetration of therapeutic agents into tumor tissues results in inadequate drug distribution and lower intracellular concentration of drugs, leading to the increase of drug resistance and resultant failure of cancer treatment. Targeted drug delivery to solid tumors followed by complete drug penetration and durable retention will significantly improve clinical outcomes of cancer therapy. Monoclonal antibodies have been commonly used in clinic for cancer treatment, but their limitation of penetrating into tumor tissues still remains because of their large size. Aptamers, as "chemical antibodies", are 15-20 times smaller than antibodies. To explore whether aptamers are superior to antibodies in terms of tumor penetration, we carried out the first comprehensive study to compare the performance of an EpCAM aptamer with an EpCAM antibody in theranostic applications. Penetration and retention were studied in in vitro three-dimensional tumorspheres, in vivo live animal imaging and mouse colorectal cancer xenograft model. We found that the EpCAM aptamer can not only effectively penetrate into the tumorsphere cores but can also be retained by tumor sphere cells for at least 24 h, while limited tumor penetration by EpCAM antibody was observed after 4 h incubation. As observed from in vivo live animal imaging, EpCAM aptamers displayed a maximum tumor uptake at around 10 min followed by a rapid clearance after 80 min, while the signal of peak uptake and disappearance of antibody appeared at 3 h and 6 h after intravenous injection, respectively. The signal of PEGylated EpCAM aptamers in xenograft tumors was sustained for 26 h, which was 4.3-fold longer than that of the EpCAM antibody. Consistently, there were 1.67-fold and 6.6-fold higher accumulation of PEGylated aptamer in xenograft tumors than that of antibody, at 3 h and 24 h after intravenous administration, respectively. In addition, the aptamer achieved at least a 4-time better tumor penetration in xenograft tumors than that of the antibody at a 200 μm distances from the blood vessels 3 h after intravenous injection. Taken together, these data indicate that aptmers are superior to antibodies in cancer theranostics due to their better tumor penetration, more homogeneous distribution and longer retention in tumor sites. Thus, aptamers are promising agents for targeted tumor therapeutics and molecular imaging.

Optimal coordination of G2V and V2G to support power grids with high penetration of renewable energy

Electric vehicles (EVs) have recently gained much popularity as a green alternative to fossil-fuel cars and a feasible solution to reduce air pollution in big cities. The use of EVs can also be extended as a demand response tool to support high penetration of renewable energy (RE) sources in future smart grid. Based on the certainty equivalent adaptive control (CECA) principle and a customer participation program, this paper presents a novel control strategy using optimization technique to coordinate not only the charging but also the discharging of EV batteries to deal with the intermittency in RE production. In addition, customer charging requirements and schedules are incorporated into the optimization algorithm to ensure customer satisfaction, and further improve the control performance. The merits of this scheme are its simplicity, efficiency, robustness and readiness for practical applications. The effectiveness of the proposed control algorithm is demonstrated by computer simulations of a power system with high level of wind energy integration.

Computer and IT skills of Australian first-year university undergraduate students

The use of computers and information technology is becoming more widespread in chemical education and in the wider community and workforce. Universities are increasing the use of computers and information technology in their teaching and learning programs. The Australian situation, reported here, can be viewed as a microcosm, reflecting a world-wide trend.

The penetration of general IT literacy and ability amongst Australian undergraduate students is rising rapidly. This paper reports surveys of the detailed IT skills of Australian undergraduate students. To the best of our knowledge, apart from our own work, there have been no other published surveys of specific IT skills. Most students have some reasonable computer skills at the start of their university studies, but the level of skill is not uniformly high. In fact, many IT literate students lack a sufficient level of skill to use the new technologies, including full use of web-based flexible learning. There is an urgent need for IT training for university students in order to achieve successful learning outcomes using IT and to satisfy the needs of future employers.

This article, which is the second in a series (1) of investigations on the computer skills of undergraduate students at the start of university, is an expanded version of a paper presented at the World Chemistry Congress held in Brisbane (Australia) during 1-6 July 2001.