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In this thesis we derive and solve mathematical models for surfactant systems with differing adsorption structures at interfaces. The first part of this thesis considers two dynamic experimental set-ups for which we derive the associated mathematical surfactant–fluid description. Firstly we consider the behaviour of a weakly interacting polymer–surfactant solution under the influence of a steady straining flow. We reduce the model using asymptotic methods to predict the regimes under which we observe phase transitions of the species in the system and show how the bulk dynamics couple to the surfactant adsorption. Secondly we model an experiment to observe the desorption kinetics of a surfactant monolayer, designed to emulate the 'rinse mechanism' used for the removal of surfactant-containing products using water. Through the comparison of our model with experimental data we derive a semi-empirical relationship that describes the variation in depth of a near-surface diffusive boundary layer with the reduced Peclet number. We then employ a combination of asymptotic and numerical techniques that validate this result. The second part of this thesis is concerned with surfactant systems that exhibit more pronounced adsorption at the interface due to the surfactant monomers no longer arranging themselves in a single layer, as is typically the case, but rather in multiple layers. Such self-assembled structures are commonly referred to as multilayers. We derive a simplified model that describes the rearrangement of surfactant within the multilayer structure and draw comparisons between the features of our model and experimental observations. We consider an extension of the theory to the situation of multilayer formation between two adsorbing interfaces, which is governed by an implicit free-boundary problem. We also consider incorporation of bulk solution effects, such as the addition of an electrolyte. Finally, we draw our conclusions and suggest further theoretical and experimental work related to the models presented in this thesis.

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Hyperbranched polymers (HBP) have drawn much attention and obtained intensive research activities from both industry and academia in the last three decades. They belong to a group of macromolecules called dendritic polymers, which have peculiar and often unique properties, which derive from their three-dimensional structure and the large number of functional groups. These structural characteristics provide high possibilities for controlling functional group interactions and modifications of other polymers in coatings and therefore, they are expected to result in novel materials with desired properties. They own a highly branched backbone, which gives access to many of reactive groups; their structure gives them excellent flow and processing properties, and they are characterized by lower viscosity than those of linear polymers of comparable molecular weight. Such properties make HBP extremely interesting for coatings and UV-curing applications and for this, they have attracted a great deal of attention for application, e.g. for powder coatings, high solid coatings, flame retardant coatings, barrier coatings for flexible packaging,and they have been recently suggested as a component of a dual-cure formulation based on an UV-curable epoxy resin and a functionalized alkoxysilane additive as an inorganic precursor to achieve advanced functional hybrid coatings. By pursuing this research line, we have synthesized an aliphatic–aromatic ethoxysilyl modified hyperbranched polyester system to be used in the preparation of UV-curable epoxy hybrid organic–inorganic coatings. The addition of ethoxysilyl-modified HBP could act as a coupling agent during the formation of the inorganic domains generated in-situ via sol-gel process starting from the alkoxysilane as inorganic precursors. The cured films were characterized in terms of their dynamic-mechanical properties and surface hardness: the obtained properties were discussed in relation to the achieved morphologies. In the present work, some aromatic hyperbranched polyesters (aHBP) and aliphatic-aromatic hyperbranched polyesters (aaHBP), OH terminated have been used as matrices for nanocomposites containing TiO2. The TiO2 nanoparticles were synthesized via sol-gel directly in a solution containing the HBP polyester as a stabilizer, and then the polymer/TiO2 hybrid mixtures were thermally cured by a curing agent to obtain a hard coating or a film. In order to determine the conditions in which it was possible to get the best dispersion and the properties for the final material, the starting HBP-OH was also partially modified with alkoxysilane groups by 3-isocyanatopropyltriethoxysilane (IPTES), yielding modified aliphatic-aromatic hyperbranched polyesters aaHBP(OH)-Si and modified aromatic hyperbranched polyesters aHBP(OH)-Si, enabling it to interact with the TiO2 network. Both materials obtained were then characterized, and their properties compared.

Manganese dioxide compounds are preferred curing agents for Polysulphide resins used as sealants in industry. These are required to have consistent setting characteristics and the investigation was initiated to characterise a number of proffered compounds of this type an to establish criteria by which an informed choice could be made of an optimum curing ages for a specific set of conditions. Several different chemical and physical properties were examined and critical parameters were established. A compound - sodium birnessite- was identified as a significant agent in the determination of curing properties. It was synthesised and its curing properties alone and in combination with other manganese dioxide compounds was evaluated. In an effort to find a specific reaction which might be used to characterise manganese dioxide curing agents it was decided to examine the classical reaction between these compounds and potassium chlorate. A literature search revealed major contradictions in the reported conditions under which potassium chlorate undergoes thermal decomposition as result of which it was decided to study the decomposition of potassium chlorate alone and in the presence of manganese dioxide and other catalysts. During this investigation a hitherto unreported high temperature structural change in potassium chlorate at 341° C was identified. The existence of this reversible change was confirmed by Powder Diffraction X-Ray analysis and an orthorhombic (near tetragonal) more open structure was assigned to it. It is suggested that the rapid decomposition of potassium chlorate in the solid state presence of catalysts is related to this change to a more open structure.

Ihr ärgert Euch über Plastik im Wald, seid genervt, wenn Ihr selber wieder etwas wegwerfen müsst? Ihr fragt Euch, ob Recycling wirklich funktioniert? Dann seid Ihr hier genau richtig: Diese kleine Broschüre ist der Anfang für das Ende der Plastikflut in Eurem Leben. Plastikmüll ist nicht nur ein Problem sterbender Meerestiere, verschmutzter Urlaubsparadiese oder armer Länder. Plastikmüll ist unser eigenes tägliches Problem, weil Energie und Ressourcen verschwendet werden, weil unsere Gesundheit gefährdet wird, weil Plastikproduktion und -müll ein Teil der Klimakrise sind. Jede und jeder Einzelne kann im Alltag Schritte in Richtung Nachhaltigkeit & Genügsamkeit gehen – in den Bereichen Konsum, Ernährung, Wohnen, Mobilität und Reisen. Ob minimalistisch oder zero-waste, plastikfrei oder DIY, ob vegan, fair, bio oder regional, ob sharing oder caring - die Möglichkeiten, einen Beitrag zu leisten, sind vielfältig! Unser Heft gibt Anregungen zur Plastikvermeidung. Stand: Mai 2019

In this study, the effects of different plant growth regulators on regeneration responses of various lentil explants through direct and indirect organogenesis and through somatic embryogenesis from calli and cell suspension cultures were investigated. Shoot regeneration was obtained in low frequencies from longitudinal embryonic axis explants and nodal buds of epicotyls, however whole plant regeneration was unsuccessful. Conditions provided for indirect organogenesis resulted only in swelling of hypocotyls and root directed ends of internodes and weak callus formation on leaves which were followed by tissue browning and necrosis. In somatic embryogenesis studies, the explants longitudinal embryonic axis and cotyledonary petioles produced soft and friable calli on MS media with Gamborg&rsquo / s vitamins supplemented with 0.75mg/L 2,4-D+0.5mg/L BA. The highest average number of embryos per explant, 12.36 was observed on media containing 0.75mg/L BA +0.5mg/L 2,4-D for cotyledonary petiole explants, whereas 3mg/L BA+1mg/L NAA was the only hormone combination that allowed embryo development to some extent, in both explants. Somatic callus failed to regenerate despite globular embryo formation and embryo development to some extent. Combination of sonication treatment with Agrobacterium transformation of three lentil explants / cotyledonary nodes, half cotyledons and cotyledonary nodes with intact shoots, had no effect on the improvement of transient gus gene expression on explants. Sonication treatment was also unable to form localized wounds on the petiole axils. The best gus gene expression on the axil region was obtained when cotyledonary nodes and KYRT1 strain were used in combination with vacuum infiltration and scalpel wounding of the axils. Gradual selection and repeated removal of regenerated shoots between selection cycles increased the number of gus expressing shoots significantly. The regenerated shoots were grafted on root stocks and whole plant regeneration was achieved in greenhouse conditions. By the use of the optimized Agrobacterium-mediated transformation protocol, 4 independent lines were obtained with 2.3% transformation efficiency. Southern blot analysis confirmed the integration of the gus gene into the genome of lentil plants. T0 plants were fertile and all plants showed Mendelian segregation of the gus gene in 3:1 ratio to their progenies except one line which carries three copies of the gene. Reverse transcription PCR has confirmed the expression of the genes in T0 and T1 generations. T0 plants and the following three generations strongly expressed gus gene uniformly in their tissues and the PCR amplifications of both gus and npt-II genes was successful through generations.

The objective of this study was to optimize tissue culture, transformation and regeneration parameters of mature embryo based culture of Triticum durum cv. Mirzabey 2000 and Triticum aestivum cv. Y&uuml / regir 89. The effects of auxin type of hormone at different concentrations and dark incubation periods on regeneration capacity were evaluated. Two different hormone types 2,4- dichlorophenoxyacetic acid and picloram were used at three different concentrations 2, 4 and 8 mg/l. Mature embryo derived calli were incubated in 6 different induction media at dark for 4 and 6 weeks for initiation of primary callus induction. After dark incubation periods, average callus fresh weight and primary callus induction rate were determined. The primary callus induction rates for 4 weeks and 6 weeks old dark adapted Mirzabey calli incubated was found to be 91 % and 93.25 % respectively. Y&uuml / regir primary callus induction rate was 92.5 % for 6 weeks old calli in 6W2D medium and 86.75 % for 4 weeks old calli in 4W8P medium. The primary calli were transferred to embryogenic callus induction medium. The embryogenic callus formation was 94.88 in 6W2D medium for Mirzabey cultivar. The necrosis was observed at high concentration of 2,4-D for both of cultivars. After embryogenic callus induction, embryogenic calli were transferred into hormone free regeneration medium. The maximum regeneration rate (62.31 %) and culture efficiency (44.13 %) were observed in 4W2D medium for Mirzabey. However, the low regeneration rate was observed for Y&uuml / regir (5 %) in 6W2D medium. The transformation studies were performed by using Obitek Biolab Gene Transfer System. The old and the modified loading units were used for optimization of bombardment pressure and distance for mature embryo based calli transformation. After bombardment of pAHC25 coated gold particles, histochemical GUS assay was performed and blue spots were counted. The transformation efficiency increased to 0.65 fold for 30 bar bombardment pressure and 5.5 fold for 35 bar bombardment by the modified loading unit. The modified loading unit could be used for further transformation studies.

Ethylene (C2H4) is a very simple molecule, a gas, and has numerous effects on the growth, development and storage life of many fruits, vegetables and ornamental crops. In higher plants, ethylene is produced from L-methionine in essentially all tissues and ACC Synthase and ACC Oxidase are the two key enzymes in the biosynthesis of ethylene. The objective of the present study was to transform tobacco (Nicotiana tabacum L. cv. Samsun) plant with partial sequence of torenia acc oxidase gene in antisense and sense orientations via Agrobacterium-mediated gene transfer system, and to analyze its effect on ethylene production in transgenic plants. Six antisense and seven sense T0 putative transgenic lines were obtained and were further analyzed with several assays. Leaf disc assay and chlorophenol red assay under selection (75 mg/L kanamycin) revealed positive results compared to the non-transformed plant. T1 generations were obtained from all putative transgenic lines. PCR analysis and Northern Blot Hybridization results confirmed the transgenic nature of T1 progeny. Furthermore, ethylene amount produced by flowers were measured with gas chromatography, which resulted in an average of 77% reduction in S7 line and 72% reduction in A1 line compared with the control flowers. These results indicated that, transgenic tobacco plants carrying torenia acc oxidase transgene both in antisense and sense orientations showed reduced ethylene production thus a possibility of flower life extension.

Isotropically conductive adhesives (ICAs) and inks are potential candidates for low cost interconnect materials and widely used in electrical/electronic packaging applications. Silver (Ag)filled ICAs and inks are the most popular due to their high conductivity and good reliability. However, the price of Ag is a significant issue for the wider exploitation of these materials in low cost, high volume applications such as printed electronics. In addition, there is a need to develop systems compatible with temperature sensitive substrates through the use of alternative materials and heating methods. Copper (Cu) is considered as a more cost-effective filler for ICAs and in this work, Cu powders were treated to remove the oxide layer and then protected with a self-assembled monolayer (SAM). The coating was found to be able to limit the re-oxidation of the Cumicron particles. The treated Cu powderswerecombined with one of two different adhesive resins to form ICAs that were stencil printed onto glass substrates before curing. The use of conventional and microwave assisted heating methods under an inert atmosphere for the curing of the Cu loaded ICAs was investigated in detail. The samples were characterised for electrical performance, microstructure and shrinkage as a function of curing temperature (80-150°C) and time. Tracks with electrical conductivity comparable to Ag filled adhesives were obtained for both curing methods and with both resins. It was found that curing could be accelerated and/or carried out at lower temperature with the addition of microwave radiation for one adhesive resin, but the other showed almost no absorption indicating a difference in curing mechanism for the two formulations.