Effect of an internal rotating current on low-frequency inductively coupled plasmas

The effects of an inductively rotating current were observed on low-frequency inductively coupled plasmas. The spatial distribution of electromagnetic fields was investigated in a cylindrical metallic chamber filled with dense plasma. The distribution of the magnetic field in plasma chamber was observed for rarefied and dense plasmas. The plasma was assumed as uniform in the electromagnetic fields. The results showed the plasma density increased with power and the electron density increased with pressure.

Internal oscillating current-sustained RF plasmas : Parameters, stability, and potential for surface engineering

A new source of low-frequency (0.46 MHz) inductively coupled plasmas sustained by the internal planar "unidirectional" RF current driven through a specially designed internal antenna configuration has been developed. The experimental results of the investigation of the optical and global argon plasma parameters by the optical and Langmuir probes are presented. It is shown that the spatial profiles of the electron density, the effective electron temperature and plasma potential feature a great deal of the radial and axial uniformity compared with conventional sources of inductively coupled plasmas with external at coil configurations. The measurements also reveal a weak azimuthal dependence of the global plasma parameters at low values of the input RF power, which was earlier predicted theoretically. The azimuthal dependence of the global plasma parameters vanishes at high input RF powers. Moreover, under certain conditions, the plasma becomes unstable due to spontaneous transitions between low-density (electrostatic, E) and high-density (electromagnetic, H) operating modes. Excellent uniformity of high-density plasmas makes the plasma reactor promising for various plasma processing applications and surface engineering.

Discharge mode transitions in low-frequency inductively coupled plasmas with internal oscillating current sheets

Transitions between the two discharge modes in a low-frequency (∼460 kHz) inductively coupled plasma sustained by an internal oscillating radio frequency (rf) current sheet are studied. The unidirectional rf current sheet is generated by an internal antenna comprising two orthogonal sets of synphased rf currents driven in alternately reconnected copper litz wires. It is shown that in the low-to-intermediate pressure range the plasma source can be operated in the electrostatic (E) and electromagnetic (H) discharge modes. The brightness of the E -mode argon plasma glow is found remarkably higher than in inductively coupled plasmas with external flat spiral "pancake" coils. The cyclic variations of the input rf power result in pronounced hysteretic variations of the optical emission intensity and main circuit parameters of the plasma source. Under certain conditions, it appears possible to achieve a spontaneous E→H transition ("self-transition"). The observed phenomenon can be attributed to the thermal drift of the plasma parameters due to the overheating of the working gas. The discharge destabilizing factors due to the gas heating and step-wise ionization are also discussed. © 2005 American Vacuum Society.

Magnetic fields and uniformity of radio frequency power deposition in low-frequency inductively coupled plasmas with crossed internal oscillating currents

Radial and axial distributions of magnetic fields in a low-frequency (∼460 kHz)inductively coupled plasmasource with two internal crossed planar rf current sheets are reported. The internal antenna configuration comprises two orthogonal sets of eight alternately reconnected parallel and equidistant copper litz wires in quartz enclosures and generates three magnetic (H z, H r, and H φ) and two electric (E φ and E r) field components at the fundamental frequency. The measurements have been performed in rarefied and dense plasmas generated in the electrostatic(E) and electromagnetic (H)discharge modes using two miniature magnetic probes. It is shown that the radial uniformity and depth of the rf power deposition can be improved as compared with conventional sources of inductively coupled plasmas with external flat spiral (“pancake”) antennas. Relatively deeper rf power deposition in the plasma source results in more uniform profiles of the optical emission intensity, which indicates on the improvement of the plasma uniformity over large chamber volumes. The results of the numerical modeling of the radial magnetic field profiles are found in a reasonable agreement with the experimental data.

Internal calibration of gel dosimeters : a feasibility study

In this work we test the feasibility of a new calibration method for gel dosimetry. We examine, through Monte Carlo modelling, whether the inclusion of an organic plastic scintillator system at key points within the gel phantom would perturb the dose map. Such a system would remove the requirement for a separate calibration gel, removing many sources of uncertainty.

Investigating the effect of internal fixation stiffness on metaphyseal fracture healing in a mouse model

This project examined the differences in healing of metaphyseal bone, when the implants of variable stiffness are used for fracture fixation. This knowledge is important in development of novel orthopaedic implants, used in orthopaedic surgery to stabilise the fractures. Dr Koval used a mouse model to create a fracture, and then assessed its healing with a combination of mechanical testing, microcomputed tomography and histomorphometric examination.

Document clustering algorithms, representations and evaluation for information retrieval

This thesis presents new methods for classification and thematic grouping of billions of web pages, at scales previously not achievable. This process is also known as document clustering, where similar documents are automatically associated with clusters that represent various distinct topic. These automatically discovered topics are in turn used to improve search engine performance by only searching the topics that are deemed relevant to particular user queries.

Book Review : "The Media Gaze: Representations of Diversities in Canada by Augie Fleras". Vancouver and Toronto: UBC Press, 2011.

The Media Gaze effectively shatters the assumption that Canada, in all its political correctness, is a cultural mosaic free of discrimination and prejudice. While great strides have been made to reduce blatant racism and sexism in Canadian media, Fleras illustrates how discriminatory and oppressive discourses are still very present in news, television, and film.He brings to light the structural, institutional, and practice-oriented means by which the media is systemically biased toward privileging mainstream audiences while misrepresenting minority groups in the public eye...

ANZAC Day media representations of women in Perth, 1960 – 2012

The annual Anzac Day observance is a focus for articulating popular notions of Australian national identity. Early Anzac Day observations were characterised by a diversity of observational modes, many distinctly masculine and militarist in character; including sports, competitions and marches. It was from the late 1920s that the now characteristic structure of the day (dawn service - march -follow-on - afternoon celebrations including eating, drinking and playing of the gambling game two-up, illegal on every other day of the year} became the dominant form. 1 Widely believed to have experienced an extended nadir in the 1960s and 1970s, since the 1980s Anzac Day has arguably become the single most important national event in the Australian calendar, involving probably the largest-numbers of Australians, many of them young, in the same temporal observance in a multitude of locations across the country and around the world.2 To date, there is a rich literature around Anzac Day observations and meanings focussing on its cultural I folkioric role'; the production of (masculinised) national identity;pilgrimage;' popular memory I history;' and the contemporary reshaping of the Anzac myth by and for indigenous participants.'

Exploring the internal dimensions of work stress : evidence from construction cost estimators in China

A recurring feature of modern practice is the stress placed on project professionals, with both debilitating effects on the people concerned and indirectly affecting project success. Cost estimation, for example, is an essential task for successful project management involving a high level of uncertainty. It is not surprising, therefore, that young cost estimators especially can become stressful at work due to a lack of experience and the heavy responsibilities involved. However, the concept of work stress and the associated underlying dimensions has not been clearly defined in extant studies in the construction management field. To redress this situation, an updated psychology perceived stress questionnaire (PSQ) , first developed by Levenstein et al (1993) and revised by Fliege et al (2005), is used to explore the dimensions of work stress with empirical evidence from the construction industry in China. With 145 reliable responses from young (less than 5 years’ experience) Chinese cost estimators, this study explores the internal dimensions of work stress, identifying four dimensions of tension, demands, lack of joy and worries. It is suggested that this four-dimensional structure may also be applicable in a more general context.

The need for internal social marketing (ISM): extending the people focus to service employees

BreastScreen Queensland (BSQ) is a government-based health service that provides free breast cancer screening services to eligible women using digital mammography technology.' In 2007, BSQ launched its first social marketing campaign' aimed at achieving a 30 per cent increase in women's programme participation by addressing the barriers to regular screening and by dispelling myths about breast cancer (Tornabene 2010). 'The Facts' mass media social marketing campaign used a credible spokesperson, Australian journalist]ana Wendt, to deliver the call to action' Don't make excuses. Make an appointment'.

Do the best scholars attract the highest speaking fees? An exploration of internal and external influence

This study investigates whether academics can capitalize on their external prominence (measured by the number of pages indexed on Google, TED talk invitations or New York Times bestselling book successes) and internal success within academia (measured by publication and citation performance) in the speakers’ market. The results indicate that the larger the number of web pages indexing a particular scholar, the higher the minimum speaking fee. Invitations to speak at a TED event, or making the New York Times Best Seller list is also positively correlated with speaking fees. Scholars with a stronger internal impact or success also achieve higher speaking fees. However, once external impact is controlled, most metrics used to measure internal impact are no longer statistically significant.

Exploring cognitive style and task-specific preferences for process representations

Process models describe someone’s understanding of processes. Processes can be described using unstructured, semi-formal or diagrammatic representation forms. These representations are used in a variety of task settings, ranging from understanding processes to executing or improving processes, with the implicit assumption that the chosen representation form will be appropriate for all task settings. We explore the validity of this assumption by examining empirically the preference for different process representation forms depending on the task setting and cognitive style of the user. Based on data collected from 120 business school students, we show that preferences for process representation formats vary dependent on application purpose and cognitive styles of the participants. However, users consistently prefer diagrams over other representation formats. Our research informs a broader research agenda on task-specific applications of process modeling. We offer several recommendations for further research in this area.

Towards a spatial language for mobile robots

We present a framework and first set of simulations for evolving a language for communicating about space. The framework comprises two components: (1) An established mobile robot platform, RatSLAM, which has a "brain" architecture based on rodent hippocampus with the ability to integrate visual and odometric cues to create internal maps of its environment. (2) A language learning system based on a neural network architecture that has been designed and implemented with the ability to evolve generalizable languages which can be learned by naive learners. A study using visual scenes and internal maps streamed from the simulated world of the robots to evolve languages is presented. This study investigated the structure of the evolved languages showing that with these inputs, expressive languages can effectively categorize the world. Ongoing studies are extending these investigations to evolve languages that use the full power of the robots representations in populations of agents.

A study of the informal interactions between audit committees and internal auditors in Australia

This paper finds evidence for the growing importance of informal interactions between the internal audit function and the audit committee (AC) in Australia – a relatively unexplored topic in the literature – using a survey of Chief Audit Executives (CAEs). It also describes the nature of these informal interactions. The most innovative elements of this paper are the findings that certain personal characteristics of CAEs, the specific knowledge and expertise of the AC chair, as well as some of the AC chair’s personal characteristics are associated with the existence (and increase) of informal interactions.