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Please read the abstract in the dissertation. Copyright / Dissertation (MEng)--University of Pretoria, 2010. / Chemical Engineering / unrestricted

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The artist discusses his Master of Fine Arts exhibition, Present Access, hosted by The Carroll Reece Museum on the campus of East Tennessee State University, Johnson City, Tennessee, from April 2 through April 25, 2007. This exhibit contains works that span his four-year tenure in the graduate program and represent several iterations of the artist's exploration of the landscape as metaphor and discovery. Subjects discussed explicate the development of thought and process leading to the pieces presented in this exhibition. Topics explored include the importance of form, material, media, research, personal history, experience, and memory. Also considered are the influences of contemporary artists such as Tula Telfair, April Gornick, Toba Khedoori, Ying Kit Chan, and Rackstraw Downes; the poetry of T. S. Eliot; the ideas of Theoretical Physics and philosopher Paul Crowther.

Flexographic printing involves driving a paper substrate through the gap between two cylinders, where one of the cylinders has a print form layer covered in ink. The ink transfer from the print form to the paper is dependent on the pressure between the paper substrate and the cylinders. Knowledge about how the paper substrate reacts to compression is therefore important when aiming for high quality flexography printing. In this project the paper substrate in focus is corrugated board consisting of a top liner, a bottom liner and a fluted paper material in between the liners. To gain knowledge about the compression dynamics of the boards they are subjected to compression experiments with and without print form. The compression experiments are filmed and the videos are then analyzed using thresholding and tracking methods. The developed thresholding method is able to measure the thickness of each material separately in each frame while the developed tracking method is able to track the movement of the top and bottom metal blocks compressing the materials. The strains calculated from the image analysis measurements are then used as input values to the Maxwell spring-dashpot model with the intention of modelling the stress. Analysis of the compression experiment videos shows that the material properties of thecorrugated board may not be constant for the duration of the compression. This is because the fluting changes its shape when being compressed. Comparing the modelled stress to the stress measured by the press used in the experiments shows that the Maxwell spring-dashpot model is not able to model the stress accurately when the corrugated board goes through multiple stages of compression. The model works better for compression where the shape of the fluting is not significantly changed.

Submitted by Marina Gruc Sztamfater (marinagruc@gmail.com) on 2015-02-27T18:33:07Z No. of bitstreams: 1 Tese_Marina_Gruc_Sztamfater.pdf: 909406 bytes, checksum: 53f3c92413eca5e92e2430768825432c (MD5) / Approved for entry into archive by Renata de Souza Nascimento (renata.souza@fgv.br) on 2015-02-27T18:34:48Z (GMT) No. of bitstreams: 1 Tese_Marina_Gruc_Sztamfater.pdf: 909406 bytes, checksum: 53f3c92413eca5e92e2430768825432c (MD5) / Made available in DSpace on 2015-02-27T19:27:56Z (GMT). No. of bitstreams: 1 Tese_Marina_Gruc_Sztamfater.pdf: 909406 bytes, checksum: 53f3c92413eca5e92e2430768825432c (MD5) Previous issue date: 2015-02-03 / This study aims to compare the forecasting efficiency of two different methodologies applied to the Brazilian shipments of corrugated board data. First the corrugated shipping data will be broken down by industrial categories of destination and for each category will be made univariate SARIMA models. The estimates of disaggregated series are then aggregated to form the prediction of the total shipment of corrugated board. The prediction made from the aggregation of industry categories will be compared with a univariate SARIMA aggregate model, in order to ascertain which of the two methods results in a model with better accuracy. This comparison will be made based on the methodology developed by Diebold and Mariano / O presente trabalho visa comparar o poder preditivo das previsões feitas a partir de diferentes metodologias aplicadas para a série de expedição brasileira de papelão ondulado. Os dados de expedição de papelão ondulado serão decompostos pelas categorias industriais de destino das caixas e serão feitos modelos do tipo SARIMA univariados para cada setor. As previsões das séries desagregadas serão então agregadas, para compor a previsão da série total de expedição. A previsão feita a partir da somatória das categorias industriais será comparada com um SARIMA univariado da série agregada, a fim de verificar qual dos dois métodos resulta em um modelo com melhor acurácia. Essa comparação será feita a partir da metodologia desenvolvida por Diebold e Mariano (1995).

The concept of sustainability is currently a prominent topic of discussion within the field of packaging. In the context of numerous product manufacturing enterprises, the integration of sustainability principles into their operational framework is often perceptible to external observers solely through the packaging of the final product. In addition to the established criteria, fundamental concepts and principles, the predominant discourse surrounding the pursuit of sustainable packaging goals primarily revolves around the specific models and practices implemented by the industry. Growing environmental concerns from industry and consumers have driven the development of innovative bio-based materials as alternatives to fossil-derived plastic polymers for packaging applications. This thesis project is in collaboration with the Swedish-Finnish company, Stora Enso Oyj; a paper mill company specialized in packaging, biomaterials, wooden construction and paper solutions, made by renewable materials, such as wood and biomass. The study involves the execution of a comparative Life Cycle Assessment (LCA) to evaluate two distinct packaging solutions. The EcoFlowerBox (EFLB), a packaging solution developed by Stora Enso, is specifically designed to cater to the needs of the floral industry. It serves as an alternative to the conventional flower bucket, fulfilling the essential functions of flower storage and transportation. The materials that were compared in the study are corrugated board and plastic, respectively. The main objective of the study was to determine the most environmentally sustainable option based on the greenhouse gas emissions generated throughout their entire life cycle. In addition to the criterion related to material composition, the ecological durability of the products was assessed by considering their end-of-life treatment and potential.  The assessment methodology discussed in this study covers the complete life cycle of the products being examined. This includes the extraction of raw materials, the manufacturing and utilization processes, and the eventual end-of-life stage.  The research findings indicate that the EcoFlowerBox (EFLB), produced by Stora Enso, exhibits a carbon footprint that is 29% lower compared to the PP bucket in the baseline scenario. This suggests that, from a climate standpoint, the EFLB functions as a more environmentally advantageous packaging solution, in terms of greenhouse gas (GHG) emissions, in comparison to the PP bucket. Additionally, the study identified that the recycling rates and the weight of the PP bucket are crucial factors that exert a substantial impact on the study's outcomes. The results underscore the significance of addressing these areas of concern in order to improve the environmental performance of the EFLB when compared to other PP buckets, and to attain more sustainable packaging solutions for flowers.

Les papiers et cartons récupérés sont aujourd’hui recyclés en nouveaux matériaux similaires, en particulier les vieux cartons sont transformés en nouveaux cartons. Riches en matière lignocellulosique, les cartons récupérés pourraient remplacer le bois dans la production de produits de plus haute valeur ajoutée. Ainsi la thèse a exploré le potentiel de procédés existants de délignification, blanchiment et purification, appliqués sur des mélanges fibreux simulant la composition de différents cartons, pour la production de pâte papetière blanchie et de pâte à dissoudre.Le traitement appliqué est composé d’une cuisson Kraft, suivie d’une séquence de blanchiment classique D0-Ep-D1 puis, dans le cas de la production de pâte à dissoudre, d’une purification de type CCE. Les cartons à traiter ayant des compositions fibreuses variables, toute l’étude a été conduite sur des mélanges fibreux modèles, composés de fibres de pâte Kraft écrue et de pâte mécanique. Dans tous les cas, des pâtes blanchies ont été produites, même si leur degré de polymérisation est parfois en deçà des standards. En revanche, les pâtes sont difficiles à purifier. Par ailleurs, il a été montré que la qualité du produit final, les performances des procédés et leur impact environnemental, dépendent de la composition fibreuse du mélange. Enfin le traitement d’un carton industriel a révélé que les charges minérales contenues dans le matériau limitent sa revalorisation.La faible qualité des pâtes blanchies obtenues a conduit à tester une autre voie de valorisation, la production de cellulose oxydée pour MFC. Un nouveau procédé de pré-oxydation pour les pâtes Kraft écrue a été développé : il combine blanchiment et oxydation du substrat dans un stade unique en utilisant le catalyseur TEMPO avec du dioxyde de chlore et de l’hypochlorite de sodium. Des MFC de qualité équivalente à celles produites à partir de pâte blanchie préoxydée par le système TEMPO/NaClO/NaBr ont été obtenues. / Today recovered papers and boards are recycled into similar products; in particular old corrugated boards are transformed into new corrugated boxes. Rich in lignocellulosic material, recovered carton boards might replace wood for the production of hgiher added-value products. The thesis investigated the potential of existing delignification, bleaching and purification processes, applied on fibre mixes simulating the composition of various carton boards, for the production of bleached paper pulp and dissolving pulp grades.The treatment was composed of a Kraft cook, followed by a conventional D0-Ep-D1 bleaching sequence, and in the case of dissolving pulp production, a CCE stage for cellulose purification. Because carton boards exhibit various fiber compositions, all the study has been conducted on model mixes, made of fibres from unbleached Kraft pulp and mechanical pulp. In all cases, bleached pulps have been successfully obtained, although pulp viscosity was sometimes below the standards. However the bleached pulps were found difficult to purify. Moreover, it has been shown that the quality of the final product, the performances of the processes and their environmental impact, depended on the fiber composition of the mix. Finally, the treatment of an industrial carton board revealed that mineral fillers contained in the material limit its upcycling.Because of the low quality of the bleached pulp produced, another valorization way was tested: the production of oxidized cellulose for MFC. A new pre-oxidation process for unbleached Kraft pulp has been developed, combining bleaching and oxidation of the substrate in a single stage combining stage combining the use of TEMPO as a catalyst, chlorine dioxide and sodium hypochlorite. MFC of same quality as those produced from bleached Kraft pulp pre-oxidized by the classical TEMPO/NaClO/NaBr system have been obtained.

Variable data will play a decisive role in the future of packaging and product promotion. Variable data printing (VDP) is a technique whereby certain information can be altered in an otherwise static layout with the help of a digital printing system, and in the packaging industry a wide range of applications is possible. Inkjet printing, due to its non-impact printing (NIP) principle, is the most suitable technology to use when applying variable data on packaging and to offer customized and even personalized prints for the industry and the end-consumer (van Daele, 2005). The aim of the work described in this thesis was to evaluate the practicability of attaining high quality variable data print (VDP) at high speed. The thesis is divided into three major parts. Part one focussed on the surface topography of corrugated board and applicable analytical methods to describe the printability of the substrate. In the second part the performance of inkjet on corrugated board liners printed at high speed was investigated and how to achieve maximum printing resolution. The final part of the thesis is devoted to a market survey of variable data printing on the North American and European markets. Part 1 concentrated on corrugated board as substrate and its pre-conditions regarding surface topography before the printing operation. Most critical for the quality are print defects such as mottling, gloss and stripiness, all of which occur in the printing of corrugated board. Stripiness is especially critical because it is one of the most disturbing print defects on corrugated board since it is periodical and more easily perceived than random print defects (Netz, 1996). Part 1 revealed that there is a difference in surface micro-roughness between the regions on the peak line of the fluting and the regions in the valley between two peaks of the corrugation which leads to glossy lines on the peak areas. The aim of the second part was to assess the practicability of attaining high quality VDP at high speed on a variety of liners for corrugated board production. The trial was conducted on a Kodak Versamark DP5240 press in Örnsköldsvik, Sweden, in cooperation with the Mid-Sweden University - Digital Printing Centre (DPC). Nine different substrates were printed at speeds between 0.5 and 5 m/s. The results revealed that the paper type rather than the printing speed has the greatest influence on the print quality. Speed, however, is the most important technical factor for inline implementation of inkjet. To obtain a picture of the industries’ view of variable data print on fibre-based packaging, a market survey was initiated and was addressed to people in the development, marketing and decision-making sectors of the packaging and printing industry, including manufacturers of machinery, producers of packaging and prints, and print buyers. The goal was to draw an overview map covering the people’s view of their market, trends in their fields and how they envision the future of VDP on fibre-based packaging. The conclusion was that inkjet technology has to prove itself first and to increase its technical capability, and the printing industry will then start investing more in this technology and in applications such as VDP. / QC 20101206

<p>The appearance and design of a package are key properties to attract and to focus the attention of a customer. Print quality contributes to a great degree to achieve these requirements. Most critical perceived in terms of quality are print defects like mottling, gloss and stripiness, which all appear in the printing of corrugated board. Stripiness is especially critical because it is a defect directly caused by the corrugated board construction. A further cause can be generated by the production process of corrugated board. Pre-studies by Odeberg Glasenapp (2004) revealed a difference in surface micro-roughness between the regions on the peak line of the liner and the regions in the valley between two peaks of the corrugation. This knowledge was the basis for the work described in this thesis.</p><p>In a first stage, laboratory trials were conducted with sets of coated and uncoated samples of various grammages. The trial was set-up in order to simulate the conditions in the corrugator as closely as possible. In the evaluations, it was found out that the settings were too high. For that reason, the coated samples were influenced to a too high degree and needed to be excluded from further evaluations. With the uncoated samples, on the other hand, a change in micro surface roughness was detectable. The roughness is decreased on the peaks and the gloss appearance was the conclusion. The analysis of the printed samples focused on shifts in colour and print density. It is unclear if both are affected only surface roughness changes and/or by the typical corrugated board effect of washboarding.</p><p>A full-scale test was performed in order to confirm the results of the laboratory test. A test series was chosen with coated and uncoated outer liners. Contrary to the lab-test results, the uncoated grades showed no surface roughness changes. Instead, the coated samples were affected to a great extent. The changes in surface roughness and gloss appearance were similar to the lab-test. This confirms that the lab-test samples were exposed to heat, pressure and shear to a too high degree. The print analysis of the full-scale test did not agree with the laboratory test. Gloss lines were visually detectable, but they were difficult to measure. A reason could be that the ink is capable on forming an ink film layer on top of the surface of the paper. This would cover the micro roughness of the matt parts thereby creating an almost homogeneous glossy appearance.</p>