This report is the result of a Master Thesis work that has been performed between October 2003 and March 2004. The purpose of the work was to evaluate a part of the signal chain in a product of Micronic Laser Systems AB. The evaluation was performed to obtain the characterisation for the signal chain, such as impedances and crosstalk. The work started with a literature study in order to refresh and increase the knowledge that was needed before the practical work. Then measurements, computer aided simulations and comparisons between these were performed. Measurements were performed using TDR (Time Domain Reflectometry). The results showed the impedance levels along the signal chain. This was interesting since it showed how well the different parts in the system are matched. Unmatched parts result in reflections that disturb the transmitted signal and contribute to crosstalk, which also was measured. Simulations were done using ADS (Advance Design System), a tool from Agilent Technologies Inc. A substantial part of the simulation work was to build models of the real system. These models have been used for simulation. The simulation results were then compared to the measurement results. The results show that the system can be better matched concerning the channel impedance. There are large variations in impedance levels along the signal chain, resulting in signal reflections. Another effect studied is crosstalk between channels. Measurements and simulations showed the presence of crosstalk but it seems to be a minor problem in the current machine.

<p>Silicone rubber based on polydimethylsiloxane is used ashigh voltage outdoor insulation, due to its ability to preservethe hydrophobic surface properties during service and evenregain hydrophobicity after exposure to electrical discharges.The underlying processes for the hydrophobic recovery arediffusion of low molar mass siloxanes from the bulk to thesurface and reorientation by conformational changes ofmolecules in the surface region. Only little is known of whichfactors are responsible for the long-term stability of thishydrophobic recovery. It is therefore important to increase theknowledge about the fundamental mechanisms for the loss andrecovery of hydrophobicity of silicone rubbers, exposed toelectrical discharges. Addition-cured polydimethylsiloxanenetworks, with known crosslink densities, were exposed tocorona discharges and air/oxygen-plasma and the loss andrecovery of hydrophobicity was characterised by contact anglemeasurements. The degree of surface oxidation increased withincreasing exposure time with a limiting depth of 100- 150 nm,as assessed by neutron reflectivity measurements. The oxidationrate increased with increasing crosslink density of the polymernetwork, according to X-ray photoelectron spectroscopy. Withinthe oxidised layer, a brittle, silica-like layer was graduallydeveloped with increasing exposure time. The hydrophobicrecovery following the corona or air/oxygen- plasma exposuresoccurred at a slow pace by diffusion of cyclic oligomericdimethylsiloxanes through the micro-porous but uncrackedsilica-like surface layer or at a much higher pace by transportof the oligomers through cracks in the silica-like layer. Theoligomers were present in the bulk, but additional amounts wereformed during exposure to corona discharges. High-temperaturevulcanised silicone rubber specimens were aged in a coastalenvironment under high electrical stress levels (100 V/mm). Thechanges in surface structure and properties were compared tothe data obtained from specimens exposed to coronadischarges/plasma. The dominating degradation mechanism wasthermal depolymerisation, initiated by hot discharges. Thisresulted in the formation of mobile siloxanes, of which the lowmolar mass fraction consisted of cyclic oligomericdimethylsiloxanes. Oxidative crosslinking resulting insilica-like surface layers was not observed during theseconditions.</p><p><b>Keywords:</b>silicone rubber, polydimethylsiloxane,hydrophobicity, corona, air-plasma, oxygen-plasma, surfacecharacterisation, degradation products, crosslink density.</p>

<p>Rechargeable batteries play an important role as energycarriers in our modern society, being present in wirelessdevices for everyday use such as cellular phones, video camerasand laptops, and also in hybrid electric cars. The batterytechnology dominating the market today is the lithium-ion(Li-ion) battery. Battery developments, in terms of improvedcapacity, performance and safety, are major tasks for bothindustry and academic research. The performance and safety ofthese batteries are greatly influenced by transport andstability properties of the electrolyte; however, both haveproven difficult to characterise properly.</p><p>The specific aim of this work was to characterise and modelthe electrolytes used in Li-ion batteries. In particular, themass transport in these electrolytes was studied throughcharacterisation and modelling of electrolyte transport in bulkand in porous electrodes. The characterisation methodology assuch was evaluated and different models were tested to find themost suitable. In addition, other properties such aselectrochemical stability and thermal properties were alsostudied.</p><p>In the study of electrochemical stability it wasdemonstrated that the electrode material influenced thevoltammetric results significantly. The most versatileelectrode for probing the electrolyte stability proved to beplatinum. The method was concluded to be suitable for comparingelectrolytes and the influences of electrolyte components,additives and impurities, which was also demonstrated for a setof liquid and polymer containing electrolytes.</p><p>A full set of transport properties for two binary polymerelectrolytes, one binary liquid and the corresponding ternarygel were achieved. The transport was studied both in the bulkand in porous electrodes, using different electrochemicaltechniques as well as Raman spectroscopy. In general, theconductivity, the salt and solvent diffusivity decreasedsignificantly when going from liquid to gel, and to polymerelectrolyte. Additionally, low cationic transport numbers wereachieved for the polymer and gel and significant salt activityfactor variations were found. The results were interpreted interms of molecular interactions. It was concluded that both theionic interactions and the influences from segmental mobilitywere significant for the polymer containing electrolytes. Thecharacterisation methods and the understanding were improved bythe use of a numerical modelling using a model based on theconcentrated electrolyte theory. It was concluded thatelectrochemical impedance spectroscopy and Raman spectroscopywere insufficient for determining a full set of transportproperties. It was demonstrated that the transport is veryinfluential on electrochemical impedance as well as batteryperformance.</p><p><b>Keywords:</b>lithium battery, electrolyte, mass transport,stability, modelling, characterisation, electrochemical, Ramanspectroscopy, impedance</p>

PLGA have already been successfully applied for controlled drug delivery systems by the pharmaceutical industry due to its biocompatibility, biodegradability and ease of processing. It has recently further been developed and formulated into a form of nanoparticle. The single emulsion evaporation method was used to prepare nanoparticles in this study. By varying different parameters such as the concentration of regents, the type of surfactant and emulsion method, different particle sizes and size distribution of PLGA nanoparticles could be obtained. The stability of PLGA nanoparticles was further investigated by assessing their thermal property over a certain period of time using DSC. The decrease of Tg confirmed the hydration and degradation of PLGA polymers and nanoparticles. The changes of surface morphology showed that the nanoparticles were in spherical shape and maintained smooth surface before the storage, whereas they started to lose their original shapes as well as agglomerate to each other after 2-week storage. These results suggested that there was an erosion and degradation of PLGA nanoparticles during storage. Ibuprofen-loaded PLGA nanoparticles have been successfully prepared by o/w single emulsion evaporation method. During the stability study, a faster degradation rate compared to non-loaded PLGA nanoparticles was exhibited, showing that Ibuprofen increased the degradation rate of PLGA nanoparticles. According to the results of drug releasing study, PLGA nanoparticles exhibiting a slower drug release rate than pure drug which proved that drug-nanoparticule system could effectively increase the stability of drugs. PLGA polymer is a potential material for drug delivery system.

No description available.

This research responds to Quebec’s call to new ways of thinking in land use planning to conserve the cultural significance of its rural landscapes. Based on guidance and approaches of the United Kingdom (UK), including historic landscape characterisation, a conservation strategy is developed and applied to the study site of Saint-Donat, Quebec. The story of the Saint-Donat landscape is told through historical narrative, GIS mapping and analysis both in time-slice and time-depth, and photographic images, which reveal values attributable to the landscape. Demonstration of how landscape policies and land use planning of Saint-Donat are informed to sustain these values is provided through application to two historic landscape character areas: the village and a mountainous recreational area. This research contributes to Canadian, Quebec and UK aims to develop a comprehensive conservation strategy for conserving cultural landscapes. Future research is needed to expand our understanding of how and why people value landscapes and the role values play in managing landscape change and landscape sustainability.

Astronomical images taken by ground-based telescopes are subject to aberrations induced by the Earth's atmosphere. Adaptive optics (AO) provides a real-time solution to compensate for aberrated wavefronts. The University of Canterbury would like to install an AO system on the 1-m McLellan telescope at Mount John University Observatory (MJUO). The research presented in this thesis is the first step towards this goal. To design an effective AO system it is important to understand the characteristics of the optical turbulence present at a site. Scintillation detection and ranging (SCIDAR) is a remote sensing method capable of measuring the refractive index structure constant, Cn2(h), and the wind velocity profile, V(h). The dominant near ground turbulence (NGT) at MJUO required the use of both pupil-plane and generalised SCIDAR. A purpose-built SCIDAR system was designed and constructed at low cost, using primarily off-the-shelf components. UC-SCIDAR saw first light at MJUO in 2003, and has since undergone several revisions. The current version employs two channels for simultaneous pupil-plane and generalised SCIDAR measurements, and is very portable. Through the use of a different mounting plate the system could be easily placed onto any telescope. Cn2(h) profiling utilised standard analysis techniques. V(h) profiling using data from a 1-m telescope is not common, and existing analysis techniques were extended to provide meaningful V(h) profiles, via the use of partial triplet analysis. Cn2(h) profiling between 2005 and 2007 indicate strong NGT and a weak turbulent layer located at 12 - 14 km above sea level, associated with the tropopause region. During calm weather conditions, an additional layer was detected at 6 - 7 km above sea level. V(h) profiles suggest that the tropopause layer velocity is nominally 12 - 30 m/s, and that NGT velocities range from 2 m/s to over 20 m/s, dependent on weather. Little seasonal variation was detected in either Cn2(h) or V(h) profiles. The average coherence length, $r_0$, was found to be 12+-5 cm and 7+-1 cm for pupil-plane and generalised measurements respectively, for a wavelength of 589 nm. The average isoplanatic angle, $\theta_0$, was 1.5+-0.5 arcseconds and 1.1+-0.4 arcseconds for pupil-plane and generalised profiles respectively. No seasonal trends could be established in the measurements for the Greenwood frequency, $f_G$, due to gaps present in the V(h) profiles obtained. A modified Hufnagel-Valley (HV) model was developed to describe the Cn2(h) profiles at MJUO. The estimated $r_0$ from the model is 6 cm for a wavelength of 589 nm, corresponding to an uncompensated angular resolution, $\theta_{res}$, of 2.5 arcseconds. $\theta_0$ is 0.9 arcseconds. A series of V(h) models were developed, based on the Greenwood wind model with an additional Gaussian peak located at low altitudes, to encompass the various V(h) profiles seen at MJUO. Using the modified HV model for Cn2(h) profiles and the suggested model for V(h) profiles in the presence of moderate ground wind speeds, $f_G$ is estimated at 79 Hz. The Tyler frequency, $f_T$, is estimated at 11 Hz. Due to financial considerations, it is suggested that the initial AO design for MJUO focuses on the correction of tip/tilt only, utilising self-guiding, as it is unlikely that any suitable guide stars would be sufficiently close to the science object. The low $f_T$ suggests that an AO system with a bandwidth in the order of 60 Hz would be adequate for tip/tilt correction.

With a growing population on earth the amount of end-of-life vehicles (ELVs) and other scrap steel increases. The European Directive 2000/53/CE” requires a minimum of 95 % reuse and recovery and 85 % re-use and recycling no later than 1 January 2015, for end-of life vehicles. This imposes a need for more efficient recycling and recovery. Despite this shredder residue (SR) is commonly land filled. This report investigated the magnetic fines residue generated at Stena Metall shredder facility in Halmstad, Sweden. Magnetic fines is a complex material containing e.g. ferrous metals, non-ferrous metals, glass, plastic, rubber, polyurethane, sand, dirt, brominated flame retardants and PCB. Characterisation of the material and discussion around area of application resulted in suggestions for possible recycling alternatives. Characterisation included e.g. particle size, total organic content, x-ray fluorescence, x-ray powder diffraction and elemental analysis with a focus on the metals. The results indicated a higher organic content in larger particles and an increasing content of e.g. lead, cadmium and mercury in smaller particles. X-ray fluorescence can be used to measure lead in magnetic fines. The conclusion was that the combustible organic content needs to be separated before further metal recycling can be applied. If magnetic fines should be used in construction pollutants probably either needs to be removed or encapsulated to prevent exposure to humans and environment.

Postmodernism is a complex concept to grasp, and although artists frequently create postmodernist work, a cognitive approach to it is difficult. This study is therefore unique in its aim to support creative writers in the formation (creation and representation) of postmodernist characters. Thus, this study contributes to the theory of creative writing, within the current zeitgeist and associated writing styles. A zeitgeist is the collective universal subconscious of the world within a specific epoch and is recognisable in the identity of the people that live during that zeitgeist, as well as in the art of the time. Postmodernism, as the contemporary zeitgeist, implies a postmodernist identity (or identities), which can creatively be represented in the artwork (literary text - prose). Through an integrated threefold study of Postmodernism (and postmodernist identity), "character" as covered in literary theory and the "creation and representation" of character as covered in the theory of creative writing, a paradigm is postulated to support the creative writer in the creation and representation of postmodernist characters. The paradigm manages postmodernist characters within three overlapping categories that approach characters as (1) icons that represent postmodernist people, as (2) literary motives that illustrate postmodernist themes and, as (3) containers of postmodernist discourses. Such a paradigm is not to be considered a model or recipe, but is instead to be viewed as an angle of approaching postmodernist characters and as a launch pad from where the creative writer must further rely on his or her own creativity, talent and dexterity. The paradigm therefore keeps in mind both the limitlessness of Postmodernism and the dynamism of the creative process. / Thesis (M.A. (Afrikaans and Dutch))--North-West University, Potchefstroom Campus, 2006

There are high demands on flexographic print quality to be sufficiently high and consistent in order to create a competitive packaging. At the same time the production efficiency need to be high. Printers thus need to achieve the same quality every time and quickly start-up new printing jobs. To accomplish this, one needs to gain a thorough understanding of how the liquid packaging board interacts with the ink and impacts the print quality. This thesis focuses on water-based ink absorption of liquid packaging boards and particularly on a) how uniformity of ink absorption can be measured and b) to what extent the absorption characteristics contribute to print mottle in flexographic printing. The work encompasses two parts. First, an absorption non-uniformity test method has been developed using a staining technique. This method is unique as it measures how unevenly an aqueous solution is absorbed, in a short time period and without impact from surface roughness. Moreover, the contributions from white-top mottle and absorption non-uniformity can be quantified simultaneously from one single measurement. Second, a method to independently study the effects of absorption non-uniformity on print quality has been established. This is achieved by introducing artificial absorption non-uniformities with well-controlled barrier patterns. A barrier pattern may modify local pore structure and/or surface energy, hence lead to lateral absorption variations. By these means, it is possible to produce a substrate property-matrix; encompassing absorption non-uniformity and for example surface roughness. It was demonstrated that non-uniform absorption indeed has a negative impact on print quality, both on smoother and rougher boards. Low absorption made print density decrease and uneven absorption caused print mottle. This was the case when other properties of the samples were kept within a narrow range; otherwise surface roughness appeared to determine print mottle ranking.