Abstract Chemistry for first year students has been identified by Tshwane University of Technology as one of the subjects with a low pass rate. It is apparent that students often memorize formulae and definitions, without understanding the underlying concepts required to work with abstract units of measure. We have found that the majority of students at this university are unable to balance reaction equations satisfactorily. They are also unable to predict the reaction yield, or identify limiting reagents. It is imperative that these and other related problems are overcome before any meaningful change to the high failure rate at first year level will be realized. All conventional forms of lecture presentation failed to make any significant impact on the success rate. Structured worksheets were developed and used, together with tactile models, to address the problems and the initial findings showed a marked improvement. It was discovered that the students’ problems originated from their inability to understand the meaning of subscripts and coefficients in chemical equations. The worksheets and the impact they have made on the students’ understanding of stoichiometry are shared in this paper.

In this thesis we carry out a further study of the back and forth error compensation and correction (BFECC) method. The first part discusses the time reversibility of numerical schemes. Motivated by the BFECC method, a variety of new numeri- cal schemes that aim at improving the time reversibility are developed and studied. We also introduce an interpolation algorithm based on BFECC in this part. In the second part we introduce a new limiting strategy which requires another backward advection in time so that overshoots/undershoots at the new time level get exposed when they are transformed back to compare with the solution at the old time level. This new technique is very simple to implement even for unstructured meshes and is able to eliminate artifacts induced by jump discontinuities in the solution itself or in its derivatives.

The computation of texture and of stereoscopic depth is limited by a number of factors in the design of the optical front-end and subsequent processing stages in humans and machines. A number of limiting factors in the human visual system, such as resolution of the optics and opto-electronic interface, contrast, luminance, temporal resolution and eccentricity are reviewed and evaluated concerning their relevance for the recognition of texture and stereoscopic depth. The algorithms used by the human brain to discriminate between textures and to compute stereoscopic depth are very fast and efficient. Their study might be beneficial for the development of better algorithms in machine vision.

During the past few decades, laser technology has had a strong impact on our society, providing important contributions to materials processing, data storage, communications, medicine, and defense applications. However, the progress in laser technology has also brought about the development of harmful portable high‐power lasers and tactical laser weapons. As a result, the hazard of being blinded by lasers (accidentally or from hostile use) has increased significantly. Hence, the need for protection against lasers has emerged. In order to protect optical sensors against harmful laser radiation, materials that absorb high intensity light, such as nonlinear absorbing chromophores, are employed. The concept of controlling the intensity of an optical light beam is usually referred to as optical power limiting and can be used efficiently in sensor protection devices.In this thesis, various nonlinear absorbing platinum(II) acetylides have been synthesized and characterized regarding their photophysical and optical limiting properties. Dendronized platinum(II) acetylides were prepared in order to evaluate the site isolation effect offered by the dendritic surrounding. The photophysical measurements reveal that the dendritic encapsulation enhances the phosphorescence, increases the luminescence lifetimes, and improves the optical limiting performance due to reduced quenching of the excited states.Triazole‐containing chromophores were synthesized using click chemistry to achieve functionalized platinum(II) acetylides. It was found that the position of the triazole unit affects the photophysical properties of these chromophores. The most promising results were obtained for the chromophore with the triazole located at the end of the conjugation where it may act as an electron donor, thus contributing to improved two‐photon absorption.A branched platinum(II) acetylide was also prepared in order to investigate the effect of multiple conjugated arms as well as multiple heavy atoms within the same molecule on the optical limiting performance. The star shaped chromophore reached the lowest clamping level of all compounds included in this thesis and constitutes a highly suitable chromophore for optical power limiting applications.The nonlinear absorbing chromophores were also incorporated into novel solid state materials based on PMMA. The actual device fabrication of doped organic glasses as optical limiters for sensor protection is presented, and their optical limiting performance is reported. The obtained organic glasses can reduce the transmission of high intensity light by 97 %. / QC 20100920

Title page, abstract and table of contents only. The complete thesis in print form is available from the University of Adelaide Library. / With the increasing use of lasers it is necessary to develop materials that can provide protection to eyes and other sensitive devices. This thesis reports on an investigation into optical limiting of Transition Metal Acetylides (TMAs) that transmit ambient light levels of light but block high energy (laser) light across the visible part of the spectrum. A standard optical limiting testbed is used to measure opt~callimiting at 470, 532 and 630 om for a wide range of Pt:ethynyl related TMAs. I report the effect on optical limiting of altering the central bridge, heavy metal, terminal group, solubilising group and oligomerisation. Most of these materials showed poor optical limiting, especially in the red. Two dimers of Pt:ethynyl, however, have clamping levels at 532 om better than that for Pt:ethynyl. I therefore describe a detailed spectroscopic investigation of two series of oligomers and discuss their structure/property relationships. This investigation also includes a precursor ofPtethynyl, PEPE, which shows remarkable limiting. I also report modelling of optical limiting using a 5-level model constructed using the spectroscopic data. I show that the 5-level model can be validated and accurately predicts the limiting for PEPE against both ps and ns pulses. It can also be used to predict ps limiting for Pt:ethynyl and its oligomers. For ns pulses, however, it predicts much less limiting than that observed. I therefore propose a new mechanism that is important for ns limiting by TMAs. Finally I discuss the broadband limiting of these materials and from analysis of the measurements· I describe structures of materials that may show promising broadband optical limiting. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1320307 / Thesis (Ph.D.) -- University of Adelaide, School of Chemistry and Physics, 2008

Title page, abstract and table of contents only. The complete thesis in print form is available from the University of Adelaide Library. / With the increasing use of lasers it is necessary to develop materials that can provide protection to eyes and other sensitive devices. This thesis reports on an investigation into optical limiting of Transition Metal Acetylides (TMAs) that transmit ambient light levels of light but block high energy (laser) light across the visible part of the spectrum. A standard optical limiting testbed is used to measure opt~callimiting at 470, 532 and 630 om for a wide range of Pt:ethynyl related TMAs. I report the effect on optical limiting of altering the central bridge, heavy metal, terminal group, solubilising group and oligomerisation. Most of these materials showed poor optical limiting, especially in the red. Two dimers of Pt:ethynyl, however, have clamping levels at 532 om better than that for Pt:ethynyl. I therefore describe a detailed spectroscopic investigation of two series of oligomers and discuss their structure/property relationships. This investigation also includes a precursor ofPtethynyl, PEPE, which shows remarkable limiting. I also report modelling of optical limiting using a 5-level model constructed using the spectroscopic data. I show that the 5-level model can be validated and accurately predicts the limiting for PEPE against both ps and ns pulses. It can also be used to predict ps limiting for Pt:ethynyl and its oligomers. For ns pulses, however, it predicts much less limiting than that observed. I therefore propose a new mechanism that is important for ns limiting by TMAs. Finally I discuss the broadband limiting of these materials and from analysis of the measurements· I describe structures of materials that may show promising broadband optical limiting. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1320307 / Thesis (Ph.D.) -- University of Adelaide, School of Chemistry and Physics, 2008

Title page, abstract and table of contents only. The complete thesis in print form is available from the University of Adelaide Library. / With the increasing use of lasers it is necessary to develop materials that can provide protection to eyes and other sensitive devices. This thesis reports on an investigation into optical limiting of Transition Metal Acetylides (TMAs) that transmit ambient light levels of light but block high energy (laser) light across the visible part of the spectrum. A standard optical limiting testbed is used to measure opt~callimiting at 470, 532 and 630 om for a wide range of Pt:ethynyl related TMAs. I report the effect on optical limiting of altering the central bridge, heavy metal, terminal group, solubilising group and oligomerisation. Most of these materials showed poor optical limiting, especially in the red. Two dimers of Pt:ethynyl, however, have clamping levels at 532 om better than that for Pt:ethynyl. I therefore describe a detailed spectroscopic investigation of two series of oligomers and discuss their structure/property relationships. This investigation also includes a precursor ofPtethynyl, PEPE, which shows remarkable limiting. I also report modelling of optical limiting using a 5-level model constructed using the spectroscopic data. I show that the 5-level model can be validated and accurately predicts the limiting for PEPE against both ps and ns pulses. It can also be used to predict ps limiting for Pt:ethynyl and its oligomers. For ns pulses, however, it predicts much less limiting than that observed. I therefore propose a new mechanism that is important for ns limiting by TMAs. Finally I discuss the broadband limiting of these materials and from analysis of the measurements· I describe structures of materials that may show promising broadband optical limiting. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1320307 / Thesis (Ph.D.) -- University of Adelaide, School of Chemistry and Physics, 2008

Title page, abstract and table of contents only. The complete thesis in print form is available from the University of Adelaide Library. / With the increasing use of lasers it is necessary to develop materials that can provide protection to eyes and other sensitive devices. This thesis reports on an investigation into optical limiting of Transition Metal Acetylides (TMAs) that transmit ambient light levels of light but block high energy (laser) light across the visible part of the spectrum. A standard optical limiting testbed is used to measure opt~callimiting at 470, 532 and 630 om for a wide range of Pt:ethynyl related TMAs. I report the effect on optical limiting of altering the central bridge, heavy metal, terminal group, solubilising group and oligomerisation. Most of these materials showed poor optical limiting, especially in the red. Two dimers of Pt:ethynyl, however, have clamping levels at 532 om better than that for Pt:ethynyl. I therefore describe a detailed spectroscopic investigation of two series of oligomers and discuss their structure/property relationships. This investigation also includes a precursor ofPtethynyl, PEPE, which shows remarkable limiting. I also report modelling of optical limiting using a 5-level model constructed using the spectroscopic data. I show that the 5-level model can be validated and accurately predicts the limiting for PEPE against both ps and ns pulses. It can also be used to predict ps limiting for Pt:ethynyl and its oligomers. For ns pulses, however, it predicts much less limiting than that observed. I therefore propose a new mechanism that is important for ns limiting by TMAs. Finally I discuss the broadband limiting of these materials and from analysis of the measurements· I describe structures of materials that may show promising broadband optical limiting. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1320307 / Thesis (Ph.D.) -- University of Adelaide, School of Chemistry and Physics, 2008

Background: The field of perinatal palliative care aims to support the unique needs of parents who choose to continue pregnancy following the diagnosis of a life-limiting fetal condition (LLFC). As parents navigate this challenging trajectory, the support they receive from healthcare providers is crucial in shaping parental experiences. Objective: to critically reflect on existing literature and to reveal a deeper understanding of the experience of continuing pregnancy in the presence of a LLFC Design: Qualitative meta-synthesis Methods: The primary search strategy consisted of multiple searches within four electronic databases. The analysis was guided by thematic analysis. Results: This meta-synthesis included 29 qualitative studies. Three main themes were identified; time, uncertainty and relationships. These concepts exist concurrently within this trajectory and continuously influence each other as well as the overall experiences of parents. Conclusion: Nurses are encouraged to acknowledge the significance of the interconnectedness between these key concepts and to critically reflect on how their everyday interactions become part of parents’ lived experiences.

9502325T Faculty of Science School of Mathematics / Abstract Increasing trees are labelled rooted trees in which labels along any branch from the root appear in increasing order. They have numerous applications in tree representations of permutations, data structures in computer science and probabilistic models in a multitude of problems. We use a generating function approach for the computation of parameters arising from such trees. The generating functions for some parameters are shown to be related to ordinary differential equations. Singularity analysis is then used to analyze several parameters of the trees asymptotically.Various classes of trees are considered. Parameters such as depth and path length for heap ordered trees have been analyzed in [35]. We follow a similar approach to determine grand averages for such trees. The model is that p of the n nodes are labelled at random in 􀀀n p(ways, and the characteristic parameters depend on these labelled nodes. Also, we will attempt to look at the limiting distributions involved. Often, when they are Gaussian, Hwang's quasi power theorem, from [18], can be employed. Spanning tree size and the Wiener index for binary search trees have been computed in [33]. The Wiener index is the sum of all distances between pairs of nodes in a tree. Arelated parameter of interest is the Steiner distance which generalises, to sets of k nodes, the Wiener index (k=2). Furthermore, the distribution of the size of the ancestor-tree and of the induced spanning subtree for random trees is presented in [30]. The same procedure is followed to obtain the Steiner distance for heap ordered trees and for other varieties of increasing trees.