In recent years, advancements in additive manufacturing (AM) technologies have paved the way for 3D-printed flexible hybrid electronics (FHE) and created opportunities for extending these gains to RF applications. However, printed metal interconnects and devices are typically characterized by high porosity and chemical impurities that significantly limit their electrical conductivity and RF performance compared to bulk equivalents. Using direct ink writing (DIW), two silver inks, a nanoflake suspension and a nanoparticle-reactive ink, were investigated to understand the relationship between free interfacial energy, sintering behavior, DC conductivity, and RF loss. The printed silver samples were characterized using scanning electron microscopy, x-ray diffraction, and x-ray photoelectron spectroscopy to monitor microstructural evolution, grain size and orientation, and chemical purity as a function of heat treatment temperature. Three heat treatments were applied to each ink: the manufacturer's recommendation, 225°C for 30 minutes, and 350°C for 30 minutes. Four-wire structures and coplanar waveguides were printed to compare the DC and RF performance up to 18 GHz, respectively. The results show that ink formulations that facilitate larger grains, high density, and good chemical purity have superior RF performance. A low resistivity of 1.4 times bulk Ag, average of 0.8% greater RF loss factor than evaporated Ag, and a maximum current density of 4.6 x 105 A/cm2 were achieved with printed structures. This work highlights the importance of engineering a high density and high purity microstructure in printed silver components necessary for high-performance printed electronics.

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Contemporary Chinese ink art is often seen as a part of an ongoing history in the Western art world, as opposed to a part of the contemporary. This thesis addresses the history of Chinese ink, the Westernization of the Chinese art world, and the major exhibitions of Chinese contemporary ink artwork that have been held in the Western world.

The title of this thesis Bottom Creek, Bent Mountain, VA is the subject of my large ink drawings. Starting with the spring outside my window, this book describes the creeks as it flows across the mountain that I grew up on. My drawings document the experience of walking along the banks of Bottom Creek as it flows past farms fields and along the roadside. Described as a seemingly insignificant place, the creek is in fact it is one of the most basic, and important parts of this mountain’s landscape, because the creek’s natural process it is responsible for producing the landscape as we see it. Through drawing the water from direct observation, I find a deeper connection to the land and respect for its ever changing processes.

>Magister Scientiae - MSc / Microfluidic paper based electrochemical sensing devices (μPEDs) provides a new way for point of care testing (POCT). μPEDs offer an inexpensive, portable, easy to use technology too monitor the environment and diagnose diseases, especially in developing countries in cases where there is not enough infrastructure and a limited trained medical and health professionals. The aim of this work is to develop a paper based electrode which can be further integrated into a microfluidic paper device to develop miniature point of care devices. Paper was used as a substrate for printing of the electrode because it is found everywhere, inexpensive and it is compatible with a number of chemical, biochemical and medical applications. Polyamic acid (PAA) was incorporated into commercial carbon ink and was used to print the working electrode. The first part of the study was conducted using the commercial screen printed carbon electrodes (SPCE) to study and understand the electrochemical behaviour of PAA. Cobalt nanoparticles and cobalt nanoparticles‐polyamic acid composites were electrochemically deposited onto SPCE. The modified electrodes were characterised using cyclic voltammetry. As synthesised polyamic acid were characterised using Scanning Electron Microscopy (SEM) to evaluate the morphology and chemical composition of polyamic acid. Transmission Electron Microscopy (TEM) was used to study the particle size and chemical composition of cobalt nanoparticles. Fourier Transform Infrared Spectroscopy (FTIR) was used to study the chemical nature of polyamic acid and cyclic voltammetry (CV) was used to study the electrochemical behaviour of polyamic acid and cobalt nanoparticle electrodes. The diffusion coefficients and formal potential of the electrodes were calculated. The modified and bare electrodes were also used to electrochemically detect Norfloxacin in an aqueous solution by CV and square wave voltammetry (SWV) and the analytical performance of the electrochemical systems are reported here. The obtained limit of detection for the bare SPCE was 3.7 x 10‐3 M and 14.7 x 10‐3 M for the PAA‐SPCE.

<p>A halftoning method with Neugebauer Primary Area Coverage direct binary search (NPAC-DBS) is developed. With the optimized human visual system (HVS) model, we are able obtain homogeneous and smooth halftone colored image. The halftoning is based on separating the colored image represented in Neugebauer Primary in three channels based on human visual system, with swap-only DBS, we arrange the dots to bring the error metric to its minimum and the optimized halftone image is obtained. The separation of chrominance HVS filters between red-green and blue-yellow channels allows us to represent HVS more accurately. Color halftone images generated using this method and method of using traditional screening methods are compared.</p> <p>In order to speed up the halftone process with similar quality of NPAC-DBS, we developed PARAWACS screens for color halftoning. PARAWACS screen is designed level by level using DBS. With PARAWACS screen, we can create halftone using simple pixel by pixel comparison with the merit of DBS. We further optimized the screen to achieve the best quality.</p> <p>Next, a novel halftoning method that we call Ink-Saving, Single-Frequency, Single-Angle, Multi-Drop (IS-SF-SA-MD) halftoning is introduced. The application target for our algorithm is high-volume production ink-jet printing in which the user will value a reduction in ink usage. Unlike commercial offset printing in which four-colorant printing is achieved by rotating a single screen to four different angles, our method uses a single frequency screen at a single angle, and it depends on accurate registration between colorant planes to minimize dot-overlap especially between the black (K) colorant and the other colorants (C, M, and Y). To increase the number of gray levels for each colorant, we exploit the multidrop capabilities of the target writing system. We also use the hybrid screening method to yield improved halftone texture in the highlights and shadows. The proposed method can help preserve ink significantly.</p>

This research project has investigated the light fastness of ink jet and electrophotographic printed materials by the means of an extensive accelerated and natural ageing test programme. The effect of visible radiation of different wavebands on the deterioration of a selection of ink jet printed materials has also been assessed. The findings of the research indicate that all of the ink jet printed materials tested are sensitive to light and should not therefore, be put on permanent display. Most of the ink jet printed samples exhibited greater light sensitivity to the shorter wavelengths of the visible spectrum, than the longer wavelengths, with damage decreasing as wavelength increases. This relationship was not evident with the cyan and blue printed samples, which showed that their light sensitivity was determined by the spectral absorption characteristics of the printed patch. Some of the ink jet printed materials produced erratic fading rates on exposure to light. This phenomenon was attributed to either the occurrence of photochromism or the disintegration of the dye particles in the ink, but further testing needs to be conducted to gain a better understanding of this reaction. Other factors also influenced the light fastness of the ink jet materials, such as the type of paper employed for printing, ink concentration and ink combination. The electrophotographic printed materials were found to be more stable to light, although the yellow toner from some of the systems would show noticeable fading after approximately 65 to 325 years on permanent display (at 50 lux for eight hours per day). A range of basic conservation treatments was also been investigated and the results indicated that ink jet print materials are very sensitive to all forms of aqueous treatments. Finally, thermal/dark ageing has been performed on the digital printed papers employed in this investigation. The conclusion is that all of the papers are prone to yellowing in storage.

My work depicts female sexual experience, particularly the complexity of the subject and corporeality. The series Pair, examines the notions of individual subjectivity as porous at the site of desire. These images explore moments of sensual experience - moments when the individual subject is destabilized and becomes indistinguishable from another. Very much like the Chinese brush painting tradition of having the viewer experience the mountain and streams in performative brush strokes, I intend to capture the feeling and expression of the body and communicate the feeling of that sexualized body with a calligraphic mark. Instead of illustrating a figure's features and thereby imposing a single narrative of the female body or sexuality, I use abstracted forms of watery mass created by pools of ink to draw the viewer into an atmosphere of erotic intensity between the two figures depicted. It is in that intensity that intimacy and connectiveness is expressed. The intertwining figures are separate entity yet they remain indistinguishable from one another, suggesting that subjectivity is destabilized. My painting isn't so much about the consciousness of mutual or co-dependency in a relationship, rather, that codependency is reinforced in the destabilization of the self during sex. I'm trying to capture a moment when both bodies opens up to each other. There are two figures depicted, yet the figures are one in the same. I can not possibly paint or express how another woman feels, I can not even paint how or what my partner feels, I can only express how my subjectivity is no-longer my own and becomes dependent and intertwine with another. So in a sense these figures express multiple selfies or are multiple self portraits. Geometric shapes outlined in gold overlays the figures and act as a placeholders for the ropes motifs that appears in my previous works, in a sense they “bound” the figures and at the same time, display the limitation of occupiable space or the limitation of their co-dependency. A gloss medium is applied to the negative space inside the geometric shape, further emphasizing the differentiated occupiable space within the metallic boundaries and the background of the painting. The fragmentary pencil images that surround the plural figures come from the same body but remain apart, suggesting an alternative narrative. They provide other possibilities of the subject or perhaps another temporal space that exist parallel to the ink figures, further affirming the corrosion of subjectivity within the subject. Since the image is abstracted and layered, the work relies on the viewer's own "perverted" imagination to create a discourse between the two figures and ultimately allows the viewer to examine their own subjectivity in moments of intimacy. Further development of my work lead me to make cuts and add layers to the painting as an action to reconsider that a painting could exist in multiple dimensional space, straddling between two and three dimensions. In consideration of Luce Irigaray's work, the act of altering the surface breaks the uniformity of the two dimensional surface and allow the transition into a three dimensional surface. It ask the viewer to consider the possibility of a painting acquiring sculptural qualities without crossing the boundary and becoming a sculpture. Assuming the logic of a painting is two dimensional, it is an representation of some image, it is fiction, where as a sculpture that occupy real space require the viewing of the object to be considered in consideration of viewer’s own body, hence sculptures is real. The act of cutting and layering suggest the transitional space from non-physical to physical, and in a sense the space between fiction to non-fiction, the unreal to real. The materiality of the paintings parallel the idea of the figure’s subjectivity, constantly shifting and altering. This allows the material and process of making to add to the self/non-self dialog of the figures.

Imagemaking is a universal impulse experienced by all human cultures. In the continual pursuit to create compelling and engaging forms, efforts to permit images to interact in dynamic ways in extended space have been the subject of considerable exploration. The often sought-after goal is to break the surface of the paper without sacrificing the essence of the image. My current research is the investigation of Smooth-On 300 series Semi-Rigid Urethane Casting Resin and its interaction with various laser jet inks on diverse paper or paper analogous mediums. Purely on accident, it was discovered that one could easily transfer printed images onto the casting resin if it was poured directly on the print. This has allowed for a method of image manipulation in a manner that has yet to be thoroughly explored. Several experimental pours and projects have been completed to test the limits and potentiality of this new media. The results seem promising and warrant farther exploration of this exciting new development.

The aim of this project is to investigate the feasibility of the use of a novel process of high liquid carryover (HLC) mode flotation to treat wastewater from a cardboard printing and coating plant. This is conducted by characterising the process conditions with the purpose of achieving a set condition that have a low susceptibility to variability in the wastewater composition. Information pertaining to the surface and physical characteristics of the solid contained in the wastewater sample were used to explain the flotation outcomes. Fe(II) was found to be more suited for industrial use as coagulant over the more commonly known coagulants, Al(III) and Fe(III), as it has the advantages of having a constant optimum flotation pH (6.5) regardless of wastewater characteristics, as well as having a much lower detrimental effect on the flotation outcome when present in excess of the minimum requirement for flocculation of wastewater solids. This allows the setting of a coagulant dose (5 mM) that will treat both high and low solids content wastewater samples. The use of cationic surfactant (CTAB) was found to require lower coagulant dosages compared to those required for anionic (SDS) or non-ionic (TericG12A8) surfactants in order to achieve good flotation outcomes. A CTAB concentration of 300 ppm was required to achieve a stable foam that can sustain for a prolonged period to allow solid (in foam)/liquid separation. The optimum batch mode conditions for HLC flotation were found to be pH 6.5, 5 mM Fe(II) and 300 ppm CTAB. This was found to correspond to a small and negative electrophoretic mobility at the wastewater solid surface and large floc size. Batch mode flotation of individual ink components under the optimum conditions for industrial wastewater treatment revealed that the presence of large quantities of either blue or yellow inks in the wastewater can lead to poor removal. Their combined presence, however, did not have detrimental effects. Continuous mode flotation at 5 mM Fe(II), 300 ppm CTAB and pH 6.5 was found to remove above 96% of contaminants at cell residence times of 6 minutes and 88% of contaminants at cell residence times of 1.5 minute. Greater than 87% of the initial wastewater volumes were recovered as treated effluent (i.e. < 13% disposed as waste foam sludge), yielding a waste foam sludge containing between 12 and 17% solids. The best flotation outcomes were achieved when all the wastewater volume entering the flotation cell leaves the cell with the foam.