Thesis (PhD)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: A new class of nanocolorants is described for the use as a colorant in hot-melt ink application for ink-jet printing technology. An inverse miniemulsion polymerization process was utilized successfully as a one-step encapsulation process to encapsulate the highly hydrophilic water-soluble fluorescent Rhodamine B dye (RhB) by the hydrophilic water-soluble poly(acrylamide) (PAAm). Three types of Rhodamine B-based nanocolorants, PAAm/RhB, crosslinked-PAAm/RhB and poly(AAm-co-Sty)/RhB, were synthesized using inverse miniemulsion polymerization. The PAAm/RhB nanocolorants exhibited solid dark nanoparticles morphology, while crosslinked-PAAm/RhB and poly(AAm-co-Sty)/RhB showed a core-shell type of morphology. The nanocolorants showed improved light and dye migration fastness as well as high thermal stability, especially, nanocolorants with core-shell morphology. The synthesis of polymerizable RhB-based nanocolorants is described. Poly(AAm-co-RhB) nanocolorants were successfully synthesized for the first time via inverse miniemulsion polymerization. RhB dye was first functionalized by esterification reaction to introduce an acrylate polymerizable group. The RhB-acrylate dye was copolymerized with AAm monomer in an inverse miniemulsion polymerization to produce nanocolorants with superior light and migration fastness. Crosslinked-poly(AAm-co-RhB) nanocolorants could be obtained based on the incorporation of a crosslinking agent. Poly(AAm-co-RhB) and crosslinked-poly(AAm-co-RhB) nanocolorants exhibited a morphology of dark solid and core-shell particles, respectively. In both nanocolorants, the RhB-acrylate dye was completely integrated by copolymerization into the polymer matrix, and by that, the dye migration was completely supressed. Both poly(AAm-co-RhB) and crosslinked-poly(AAm-co-RhB) nanocolorants showed high thermal stability as well as high Tg values. The syntheses of PAAm/RhB nanocolorants-based solid inks were carried out successfully via inverse miniemulsion polymerization. An in situ inverse miniemulsion polymerization, with the paraffin wax as the organic phase, was utilized in making a crosslinked-PAAm/RhB nanocolorants-based solid ink. A crosslinked-poly(AAm-co-RhB) nanocolorants-based solid ink was prepared by the direct mixing of the readymade crosslinked-PAAm/RhB nanocolorants (suspended in cyclohexane) with paraffin wax at temperature above the melting temperature of the wax until all the cyclohexane evaporated. The obtained solid inks appeared as a solid homogenous waxy material with a deep bright colour reflecting that the nanocolorants were well dispersed in the wax. DSC thermograms showed that the solid inks have one sharp melting transition indicating the applicability of our nanocolorants for hot-melt ink applications. / AFRIKAANSE OPSOMMING: ‘n Nuwe reeks nonokleursels word beskryf vir die gebruik in ink-smelt drukker tegnologie. Inverse minie-emulsie polymerisasie was suksesvol gebruik om die kleurstof Rhodamine B (RhB) in die water oplosbare poly(akrielamied) (PAAm) te enkapsuleer. Die roete is gebruik om drie tipes kleurstof te produseer. Elk van die kleurstowwe was gebaseer op Rhodamine B en ‘n PAAm, naamlik PAAm/RhB, kruisgebonde PAAm/RhB en poli(akrielamied-ko-stireen)/RhB. PAAm/RhB nanokleursel was in die vorm van soliede donker nanopartikels. Die kruisgebonde PAAm/RhB en poli(akrielamied-ko-stireen) het bestaan uit nanoparikels met ‘n kern en skil morfologie. Die nanokleursels het ‘n verbetering in terme van lig en hitte stabiliteit getoon. Die migrasie van kleursel uit die nanopartikels, veral die met kern en skil morfologie, was baie minder. Die sintese van ‘n polimeeriseerbare nanokleursel gebaseer op RhB word beskryf. Poly(AAm-ko-RhB) nanokleursels was vir die eerste keer suksesvol gesintetiseer met behulp van ‘n inverse minie-emulsie polimerisasie. RhB kleursel was eers gefunksionaliseer deur middel van ‘n esterifikasie reaksie om ‘n polimeeriseerbare akrilaat groep te verkry. Die RhB-akrilaat kleursel was gekopolimeeriseer met AAm monomeer in ‘n inverse minie-emulsie polimerisasie om nanokleursels met verbeterde lig en migrasie stabiliteit te verkry. Kruisgebonde poli(AAm-ko-RhB) nanokleursels was verkry deur ‘n geskikte verbinding in die reaksie mengsel by te voeg. Beide poli(AAm-ko-RhB) and kruisgebonde poly(AAm-ko-RhB) nanokleursels was verkry as donker partikels met ‘n kern en skil morfologie. In beide gevalle was die RhB-akrilaat kleursel deeglik geintegreer in die matriks en sodoende was die migrasie van die kleursel heeltemal onderdruk. In albei gevalle het poli(AAm-ko-RhB) en kruisgebonde poli(AAm-ko-RhB) nanokleursels hoë hitte stabiliteit en hoë Tg waardes getoon. Die sintese van nanokleursels gebaseer op PAAm/RhB was sukselvol uit gevoer via inverse minie-emulsie polimerisasie. ‘n In situ inverse minie-emulsie polimerisasie met paraffin waks as die organiese fase was gebruik om soliede ink te produseer wat opgemaak is uit kruisgebonde PAAm/RhB nanokleursel. Die kruisgebonde poli(AAm-ko-RhB) soliede ink was voorberei deur die kruisgebonde PAAm/RhB nanokleursels (in suspensie met sikloheksaan) direk met die paraffin waks te meng by ‘n temperatuur hoër as die smeltpunt van die waks todat al die sikloheksaan verdamp het. Die soliede ink was verkry as ‘n homogene waksagtige materiaal met ‘n diep en helder kleur wat ‘n aanduiding was dat die nanokleursels goed versprei was in die waks. DSC termogramme het bewys dat die ink slegs een skerp smelt punt oorgang het wat beteken dat die materiaal geskik is om te gebruik in ink-smelt drukkers.

Inkjet-printed memory cards have been developed previously by re-searchers at Mid Sweden University but, these did possess some limita-tions, as each resistive memory cell required one physical contact and the resistances were designed to be electrically programmed.This work overcomes the above limitations by developing chemically programmed printed memory cards and a PC connected memory card reader. Printed memory cards are inexpensive and are developed by inkjet printing the nano-silver ink onto the photo paper substrate. A matrix readout method is used to increase the num-ber of memory cells and, by using a chemical solvent, the resistances were programmed to the desired resistance values and, for which, each resistance value represents data on the cards, called, write once read many (WORM) memories. The memory card reader was developed to access the data (resistance value) of the memory card and also to trans-mit the data to a LabVIEW graphical user interface for displaying the resistance values. By using multiple resistance steps, in which each step represents a different state, it is possible to create a number of possible selectable combinations which can be programmed at a later stage for developing applications.

The following experimental study was conducted to test these hypotheses. The subjects used in the study were twenty-five males and twenty-five females from undergraduate courses in psychology at the freshman and sophomore levels. Procedure.--Each subject was administered the Rorschach test, in the manner described by Beck (1961), except that the subject was seated facing the test administrator. Each subject was also administered the MMPI, using,.Form R.

The intention behind my work is to draw the viewer's attention to the intimate, beautiful details found in nature. For example, I am awed and inspired by the unique qualities found in every tree whose varieties are seemingly infinite. The basic concept of my work is to portray the images of trees close to the viewer's eye to instill a sense of nature's grandness.

This is a textile design project aim to make acommunication stage with smart colors (Thermo-­‐chromic leuco-­‐dyes and photo-­‐luminescent colors). Allthrough a research question has been designed. Theobjects, colors, and materials have been chosen basedon the inspirations from the stimuli. Afterwardexperimental method has been employed to reflect thetheory of the project, which was the notion of death andlife. Subsequently the design process has been startedby conception of combining textile and informationtechnology in order to make a design prototype sopeople can interact with the prototype and reactionscould be observed and sensed by human. Thiscommunication stage has its own specifications andcharacteristics that people can have their ownunderstanding of it while using it. / Program: Master Programme in Fashion and Textile Design

L'objectif principal de la présente étude est de développer des encres à base de graphène présentant d'excellentes propriétés de stabilité, électriques et physiques pour l'électronique d'impression en utilisant des techniques de revêtement par pulvérisation et d'impression par jet d'encre. Premièrement, la comparaison des différents types de matériaux similaires au graphène a montré que la mousse de graphène (GF) présentait la plus grande surface spécifique avec une valeur de 2136 m2g-1. Par ailleurs, les nanoplaquettes de graphite (GNPs) et le graphite synthétique (SG) présentaient des structures hautement cristallines avec la présence d'un pic aigu et étroit (002) et de particules de haute qualité avec un rapport ID/IG inférieur. Deuxièmement, les résultats ont montré que la viscosité et l'angle de contact des encres conductrices augmentaient significativement avec l'augmentation des charges de GF, GNPs et SG dans un liant de vernis polyester (PV). L'incorporation de 10 % en volume de PNB a amélioré la conductivité électrique du PV de 186 %, et seulement 40 % pour la SG et 10 % pour le GF avec la même charge de remplissage. Ensuite, il a été constaté que les PNB dispersés dans l'éthylène glycol (EG) présentaient une meilleure stabilité avec une diminution de 85% de la concentration initiale après un mois, une viscosité et une mouillabilité supérieures à celles du propylène glycol (PG) et du 2-propanol (IPA). D'autre part, le GF dispersé dans un solvant mélangé IPA:EG avec un rapport de 1:1 n'a montré qu'une diminution de 50 % par rapport à la concentration initiale après un mois comparant à ceux des encres GNP dans le même rapport de mélange. Dans la dernière partie, l'encre hybride GF/poly(3,4-éthylènedioxythiophène) poly(styrène-sulfonate) (PEDOT:PSS) a montré une meilleure stabilité que l'encre hybride GF et l'encre hybride GF/nanoparticules d’argent (AgNPs) où l'encre a montré 30 % de réduction de concentration après un mois, 100 % d'amélioration en termes de conductivité superficielle à 50 couches imprimées et un facteur de gauge de 4.3. En conclusion, l'encre hybride imprimée GF/PEDOT:PSS a le potentiel d'être utilisée pour les applications de capteurs de contrainte. / The main aim of the present study is to develop graphene-based ink with excellent stability, electrical and physical properties for printing electronics by utilizing spray coating and inkjet printing techniques. Firstly, comparison on the different types of graphene-like materials showed that graphene foam (GF) exhibited the highest surface area with the value of 2136 m2g-1. Meanwhile, graphite nanoplatelets (GNPs) and synthetic graphite (SG) displayed highly crystalline structures with the presence of sharp and narrow (002) peak, and high-quality particles with lower ID/IG ratio. Secondly, results showed that viscosity and contact angle of the conductive inks increased significantly with increasing GF, GNPs and SG filler loadings in a polyester varnish (PV) binder. The incorporation of 10 vol.% GNPs improved the electrical conductivity of PV by 186 %, and only 40 % for SG and 10 % for GF at the same filler loading. Next, it is found that GNPs dispersed in ethylene glycol (EG) exhibited better stability with 85 % decrement of the initial concentration after a month, viscosity and wettability than those of propylene glycol (PG) and 2-propanol (IPA). On the other hand, GF dispersed in IPA:EG mixed solvent at ratio of 1:1 showed only 50 % decrement from the initial concentration after a month compared to those of GNPs inks at the same mixed ratio. In the last part, GF/poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) hybrid ink exhibited better stability than GF ink and GF/silver nanoparticles (AgNPs) hybrid ink where the ink showed 30 % decrement from the concentration after a month, 100 % improvement in surface conductivity at 50 printed layers and gauge factor of 4.3. As a conclusion, printed GF/PEDOT:PSS hybrid ink has the potential to be used for strain sensor applications.

Improvements in printing technology have exacerbated the problem of document counterfeiting, prompting the need for analytical techniques that better characterize inks for forensic analysis. In this study, 319 printing inks (toner, inkjet, offset, and intaglio) were analyzed directly on the paper substrate using Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS) and Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS). As anticipated, the high sensitivity of LA-ICP-MS resulted in excellent discrimination (> 99%) between ink samples originating from different sources. Moreover, LA-ICP-MS provided ≥ 90% correct association for ink samples originating from the same source. SEM-EDS resulted in good discrimination for toner and intaglio inks (> 97%) and excellent correct association (100%) for all four ink types. However, the technique showed limited utility for the discrimination of inkjet and offset inks. A searchable ink database, the Forensic Ink Analysis and Comparison System (FIACS), was developed in order to provide a tool that allows the analyst to compare a questioned ink sample to a reference population. The FIACS database provided a correct classification rate of 94-100% for LA-ICP-MS and 67-100% for SEM-EDS. An important consideration in forensic chemistry is the interpretation of the evidence. Typically, a match criterion is used to compare the known and questioned sample. However, this approach suffers from several disadvantages, which can be overcome with an alternative approach: the likelihood ratio (LR). Two LA-ICP-MS glass databases were used to evaluate the performance of the LR: a vehicle windshield database (420 samples) and a casework database (385 samples). Compared to the match criterion, the likelihood ratio led to improved false exclusion rates (< 1.5%) and similar false inclusion rates (< 1.0%). In addition, the LR limited the magnitude of the misleading evidence, providing only weak support for the incorrect proposition. The likelihood ratio was also tested through an inter-laboratory study including 10 LA-ICP-MS participants. Good correct association rates (94-100%) were obtained for same-source samples for all three inter-laboratory exercises. Moreover, the LR showed a strong support for an association. Finally, all different-source samples were correctly excluded with the LR, resulting in no false inclusions.

<p>During a make ready in a web offset press it is important to produce as little waste as possible. Reducing the amount of waste yields savings of both time and money. One way to do faster make ready is to preset the ink keys of the press before it is started. </p><p>This diploma work, carried out at Sörmlands Grafiska Quebecor AB in the city of Katrineholm, Sweden, examines how the ink key preset may be done using low- resolution digital images stored in the vendor independent data format CIP3 PPF. The press that has been used has a control interface that is not accessible from the outside. This feature is shared with a lot of older presses. Therefore several methods of how to present and collect ink key settings using offline methods have been tested. </p><p>To investigate the relationship between mean coverage over one ink zone and its corresponding ink key opening data from a 32-page web offset press has been collected. The mean coverage was taken from the CIP3 PPF files that were related to the collected print jobs. </p><p>The relationship that was found between the coverage and the opening can be described with a transfer curve (one curve per printing unit and side). Using as few as three print jobs of high quality (density and dot gain within given tolerances) a first set of transfer curves may be created. These are close to the real ones and using print jobs where the ink key presettings have been calculated the transfer curves may be calibrated to perform better and better presetting calculations. To generate and calibrate the transfer curves and to extract the mean coverage values from the CIP3 PPF files and recalculate these to presetting values a computer program called IKPS (Ink Key Presetting System) was made. IKPS was made using MATLAB from MathWorks INC. </p><p>IKPS have been tested for ink key presetting during a number of print jobs. Even though the transfer curves were uncalibrated the system performed well. As comparison the results from a plate scanner was used. Even if online transfer of the presetting values is preferable the big advantage with the IKPS is that it is an offline system and therefore it is possible to implement it on any kind of offset press, old as well as new. In order to generate reliable transfer curves the print jobs used for calibration must be of high printing quality and representative for that particular press. How the ink key presettings are presented in the press control room depends on what kind of press it is. IKPS works with CIP3 PPF files as well as low-resolution cmyk tiff files.</p>

<p>Because of their compatibility and precise results bio-optical methods based on measurements of the optical tissue properties gain importance in non-invasive medical therapy and diagnostic. For development and standardization of medical devices optical phantoms are suitable. The present report handles the creation and evaluation of solid tissue phantoms, made up of Agar, Vasolipid and ink utilizing different mixture ratios. After cutting the models in slices of 0.2 to 1.1 mm thickness the absorption- and scattering coefficient were measured using a collimated laser beam setup. As result of the study a formula for the preparation of solid optical tissue phantoms with desired optical properties was found, that is valid for models containing 1.12 % Agar.</p>

<p>Inkjet is a digital printing process where the ink is ejected directly onto a substrate from a jet device driven by an electronic signal. Most inkjet inks have a low viscosity and a low surface tension, which put high demands on the coating layer’s porosity and absorbency characteristics.</p><p>The aim of this study has been to gain an increased knowledge of the mechanisms that control the sorption and fixation of inkjet inks on coated papers. The focus has been on printability aspects of high print quality (although not photographic quality) laboratory-coated inkjet papers for printers using aqueous-based inks.</p><p>Papers coated solely with polyvinyl alcohol (PVOH) and starch presented excellent gamut values and good print sharpness over the uncoated substrate, due to good film-forming characteristics observed by light microscopy and ESCA. ESEM analyses showed the complexity and variation of PVOH surface structures, which has probably explained the wide scatter in the colour-to-colour bleed results. Pure PVOH coatings also gave a surface with high gloss variations (2-8 times greater than that of commercial inkjet papers), prolonged ink drying time, and cracked prints when using pigmented inks. When an amorphous silica gel pigment (with broad pore size distribution) was used in combination with binder, a new structure was formed with large pores in and between the pigments and a macro-roughness generated by the large particles. The inkjet ink droplets could quickly penetrate into the large pores and the time for surface wicking was reduced, which was beneficial for the blurriness. However, the macro-roughness promoted bulk spreading in the coarse surface structure, and this tended to increase the line width. Finally, when the ink ends up within the coating, the colorant is partly shielded by the particles, and this reduced the gamut area to some extent. The binder demand of the silica pigments was strongly related to their pore size distributions. Silica gel required two to three times the amount of binder compared to novel surfactant-templated mesoporous silica pigments (with small pores and narrow pore size distribution). This finding was attributed to the significant penetration of PVOH binder into the pores in the silica gel, thereby, increasing its binder demand. Furthermore, this binder penetration reduced the effective internal pore volume available for rapid drainage of the ink vehicle. Consequently, the surfactant-templated pigments required significantly lower amounts of binder, and gave improvements in print quality relative to the commercial pigment.</p>