Operation and control of a DVR in the presence of interharmonics

The paper discusses the operating principles and control characteristics of a dynamic voltage restorer (DVR). It is assumed that the source voltages contain interharmonic components in addition to fundamental components. The main aim of the DVR is to produce a set of clean balanced sinusoidal voltages across the load terminals irrespective of unbalance, distortion and voltage sag/swell in the supply voltage. An algorithm has been discussed for extracting fundamental phasor sequence components from the samples of three-phase voltages or current waveforms having integer harmonics and interharmonics. The DVR operation based on extracted components is demonstrated. The switching signal is generated using a deadbeat controller. It has been shown that the DVR is able to compensate these interharmonic components such that the load voltages are perfectly regulated. The DVR operation under deep voltage sag is also discussed. The proposed DVR operation is verified through the computer simulation studies using the MATLAB software package.

Technology : new horizons in teaching law

17.1 Up until the 1990s the methods used to teach the law had evolved little since the first law schools were established in Australia. As Keyes and Johnstone observed: In the traditional model, most teachers uncritically replicate the learning experiences that they had when students, which usually means that the dominant mode of instruction is reading lecture notes to large classes in which students are largely passive. Traditional legal education has been described in the following terms: Traditionally law is taught through a series of lectures, with little or no student involvement, and a tutorial programme. Sometimes tutorials are referred to as seminars but the terminology used is often insignificant: both terms refer to probably the only form of student participation that takes place throughout these students‘ academic legal education. The tutorial consists of analysing the answers, prepared in advanced (sic), to artificial Janet and John Doe problems or esoteric essay questions. The primary focus of traditional legal education is the transmission of content knowledge, more particularly the teaching of legal rules, especially those drawn from case law. This approach has a long pedigree. Writing in 1883, Dicey proposed that nothing can be taught to students of greater value, either intellectually or for the purposes of legal practice, than the habit of looking on the law as a series of rules‘.

Waterfall : Nature and Culture

Many people take pleasure in visiting waterfalls and much has been written on the subject. Numerous accounts of Niagara Falls were published after Hennepin's late seventeenth-centure descriptions, particularly from the early nineteenth century, but is was only later that other waterfalls became the subject of books. George Holley's Niagara and Other Famous Cataracts of the World, published in 1883, and John Gibson's Great Waterfalls, Cataracts and Geysers, published in 1887, are early examples of global accounts of major falls. Most books about waterfalls are guides to the falls of a particular country, state or region. Apart from a few slim illustrated volumes, few books have been puslished on the world's waterfalls since Edward Rashleigh's Among the Waterfalls (1935). Most of these are slim pictorial volumes, some aimed at the children's market. Geologist Richard Maxwell Pearl published a series of waterfall articles in his journal Earth Science between 1973 and 1975, apparently with the intention of turning them into a book, but this never materialized. My book, the culmination of more than a decade of waterfalls research, is comprehensive in its approach, but is not intended to describe as many of the world's waterfalls as possible. This is far from my aim, and readers may be disappointed at my omission of falls they feel deserved mention. What I have attempted to do is celebrate the delights of these beautiful wonders of nature by considering them from many points of view, emphasizing the roles that they play in the human experience. To be as representative as possible, I draw on examples of waterfalls from all over the world, some famous, many not. North and South America, Europe, Africa, Asia and Oceania and, with recent global warming, the Earth's polar regions, all feature in the discussion. Even though there are already enough books and articles about Niagara Falls to fill a large library, it has been impossible to avoid making frequent reference to this great cataract, which has been so important in the history of travel and tourism, power generation, urban development and art. Amoung the issues that I consider is the human impact on waterfalls, particularly the effects of hydropower schemes and tourism development. Also considered are artificial waterfalls, which have long been features of the designed landscape. Their contemporay role is poignantly exemplified in the design of the National September 11 Memorial, in which the footprints of the Twin Towers are traced by walls of waterfalls. A geographer and urban and regional planner by training, I have ventured into many other fields of knowledge that are outside my areas of expertise. I apologize for any errors that I may have made in my book and invite correction.

A qualitative exploration of young women's drinking experiences and associated protective behaviours

While initial research supports the effectiveness of protective strategies in mitigating young people’s alcohol-related harm, few studies have investigated these behaviours from a uniquely female perspective. Yet, young women consume alcohol within a social context that is distinctly different from that of young men and face risks that are specific to their gender. To explore a group of young Australian women’s experiences, perceptions of risks and use of protective strategies in relation to drinking in public places, we conducted either focus groups or one-on-one telephone interviews with a total of 40 women aged 18–24 years. While young women reported substantial risks associated with drinking, they also reported using a range of protective behaviours that moderated the adverse effects of alcohol, with most of these strategies being derived from the friendship group to which the women belonged. Our findings add to the limited body of knowledge on women’s insights into, and their use of protective strategies to minimise the negative consequences of alcohol.

Maiden, Joseph

Joseph Henry Maiden was born in London in 1859 and sailed for Australia in 1880, where he lived for the remainder of his life. He was an ardent Australian nationalist, and like many immigrants of this time, remained proud of his British heritage. His sweetheart, Eliza Jane Hammond, followed him to Australia in 1883. They married in Kew the day after she made port in Melbourne, and together in Sydney they raised five children. [1] During the first phase of his career Maiden presided over the Technological Museum of Sydney from 1882 to 1896. In the second phase, he was the director of the Sydney Botanic Gardens from 1896 to 1924. There he managed a whole complex of parks including the Domain,Centennial Park and the Governor's residences, a state nursery at Campbelltown and a scientific institution, the National Herbarium of New South Wales, devoted to botany. A short time after his retirement, he died at his home in Turramurra in 1925...

Improved energy harvesting capability of poly(vinylidene fluoride) films modified by reduced graphene oxide

Piezoelectric energy harvesters can be used to convert ambient energy into electrical energy and power small autonomous devices. In recent years, massive effort has been made to improve the energy harvesting ability in piezoelectric materials. In this study, reduced graphene oxide was added into poly(vinylidene fluoride) to fabricate the piezoelectric nanocomposite films. Open-circuit voltage and electrical power harvesting experiments showed remarkable enhancement in the piezoelectricity of the fabricated poly(vinylidene fluoride)/reduced graphene oxide nanocomposite, especially at an optimal reduced graphene oxide content of 0.05 wt%. Compared to pristine poly(vinylidene fluoride) films, the open-circuit voltage, the density of harvested power of alternating current, and direct current of the poly(vinylidene fluoride)/reduced graphene oxide nanocomposite films increased by 105%, 153%, and 233%, respectively, indicating a great potential for a broad range of applications.

Alcohol-related emergency department injury presentations in Queensland adolescents and young adults over a 13-year period

Introduction and Aims. The rate of alcohol-related emergency department (ED) presentations in young people has increased dramatically in recent decades. Injuries are the most common type of youth alcohol-related ED presentation, yet little is known about these injuries in young people. This paper describes the characteristics of alcohol-related ED injury presentations in young people over a 13-year period and determines if they differ by gender and/or age group (adolescents: 12–17 years; young adults: 18–24 years). Design and Method. The Queensland Injury Surveillance Unit (QISU) database collects injury surveillance data at triage in participating EDs throughout Queensland, Australia. A total of 4667 cases of alcohol-related injuries in young people (aged 12–24 years) were identified in the QISU database between January 1999 and December 2011, using an injury surveillance code and nursing triage text-based search strategy. Results. Overall, young people accounted for 38% of all QISU alcohol-related ED injury presentations in patients aged 12 years or over. The majority of young adults presented with injuries due to violence and falls, whereas adolescents presented due to self-harm or intoxication without other injury. Males presented with injuries due to violence, whereas females presented with alcohol-related self-harm and intoxication. Discussion and Conclusions. There is a need for more effective ways of identifying the degree of alcohol involvement in injuries among young people presenting to EDs.

The contribution of three components of nutrition knowledge to socio-economic differences in food purchasing choices

Objectives: To assess socio-economic differences in three components of nutrition knowledge, i.e. knowledge of (i) the relationship between diet and disease, (ii) the nutrient content of foods and (iii) dietary guideline recommendations; furthermore, to determine if socio-economic differences in nutrition knowledge contribute to inequalities in food purchasing choices. Design: The cross-sectional study considered household food purchasing,nutrition knowledge, socio-economic and demographic information. Household food purchasing choices were summarised by three indices, based on self-reported purchasing of sixteen groceries, nineteen fruits and twenty-one vegetables. Socio-economic position (SEP) was measured by household income and education. Associations between SEP, nutrition knowledge and food purchasing were examined using general linear models adjusted for age, gender, household type and household size. Setting: Brisbane, Australia in 2000. Subjects: Main household food shoppers (n 1003, response rate 66?4 %), located in fifty small areas (Census Collectors Districts). Results: Shoppers in households of low SEP made food purchasing choices that were less consistent with dietary guideline recommendations: they were more likely to purchase grocery foods comparatively higher in salt, sugar and fat, and lower in fibre, and they purchased a narrower range of fruits and vegetables. Those of higher SEP had greater nutrition knowledge and this factor attenuated most associations between SEP and food purchasing choices. Among nutrition knowledge factors, knowledge of the relationship between diet and disease made the greatest and most consistent contribution to explaining socio-economic differences in food purchasing. Conclusions: Addressing inequalities in nutrition knowledge is likely to reduce socio-economic differences in compliance with dietary guidelines. Improving knowledge of the relationship between diet and disease appears to be a particularly relevant focus for health promotion aimed to reduce socio-economic differences in diet and related health inequalities.

Polyacrylic Acid Assisted Synthesis of Cu2ZnSnS4 by Hydrothermal Method

Pure phase Cu2ZnSnS4 (CZTS) nanoparticles were successfully synthesized via polyacrylic acid (PAA) assisted one-pot hydrothermal route. The morphology, crystal structure, composition and optical properties as well as the photoactivity of the as-synthesized CZTS nanoparticles were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectrometer, UV-visible absorption spectroscopy and photoelectrochemical measurement. The influence of various synthetic conditions, such as the reaction temperature, reaction duration and the amount of PAA in the precursor solution on the formation of CZTS compound was systematically investigated. The results have shown that the crystal phase, morphology and particle size of CZTS can be tailored by controlling the reaction conditions. The formation mechanism of CZTS in the hydrothermal reaction has been proposed based on the investigation of time-dependent phase evolution of CZTS which showed that metal sulfides (e.g., Cu2S, SnS2 and ZnS) were formed firstly during the hydrothermal reaction before forming CZTS compound through nucleation. The band gap of the as-synthesized CZTS nanoparticles is 1.49 eV. The thin film electrode based on the synthesized CZTS nanoparticles in a three-electrode photoelectrochemical cell generated pronounced photocurrent under illumination provided by a red light-emitting diode (LED, 627 nm), indicating the photoactivity of the semiconductor material.

Prediction of heparin binding sites in bone morphogenetic proteins (BMPs)

Heparin is a glycosaminoglycan known to bind bone morphogenetic proteins (BMPs) and the growth and differentiation factors (GDFs) and has strong and variable effects on BMP osteogenic activity. In this paper we report our predictions of the likely heparin binding sites for BMP-2 and 14. The N-terminal sequences upstream of TGF-β-type cysteine-knot domains in BMP-2, 7 and 14 contain the basic residues arginine and lysine, which are key components of the heparin/HS-binding sites, with these residues being highly non-conserved. Importantly, evolutionary conserved surfaces on the beta sheets are required for interactions with receptors and antagonists. Furthermore, BMP-2 has electropositive surfaces on two sides compared to BMP-7 and BMP-14. Molecular docking simulations suggest the presence of high and low affinity binding sites in dimeric BMP-2. Histidines were found to play a role in the interactions of BMP-2 with heparin; however, a pKa analysis suggests that histidines are likely not protonated. This is indicative that interactions of BMP-2 with heparin do not require acidic pH. Taken together, non-conserved amino acid residues in the N-terminus and residues protruding from the beta sheet (not overlapping with the receptor binding sites and the dimeric interface) and not C-terminal are found to be important for heparin–BMP interactions.