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This essay reports from a study using XRF of thirteen glass fragments found in the harbour of the Viking town of Birka some interesting observations were made. Two fragments are coloured using antimony and manganese. One fragment could have been made using wood ash glass. Two fragments contain chromium which might imply provenance from Lorraine- Alsace.

A range of new mixed metal carboxylate ((M(O2CR)n) glasses has been prepared. Typically, Mn+ = alkali metals, alkaline earth metals, Zn2+, Pb2+, Sn2+, Co2+ and Cu2+. R increases from CH3 to C7H15 and higher. The alkyl chain can also be branched or aromatic. The properties of these glasses are affected by both the metal cations and carboxylate anions. Densities range from 1.2 to 2.7 g cm-3 and refractive indices from 1.4 to 1.6. Transparency has been shown to extend from 250 to 1400 nm. The carboxylate mixtures could be maintained in the molten state, at temperatures ranging from 100-200°C for prolonged periods without decomposition. Glass transition temperatures have been determined; these generally extended from 30°C up to 60°C. The melts were excellent solvents for a wide range of organic compounds. These dissolved in the carboxylate melts with no appreciable decomposition. The melts could then be quenched to give monolithic glass matrices. By choosing specifically designed organic compounds, the glasses have potential application for photochromism, electrochromism and non-linear optics. Investigation of the solubility of the glasses in water indicated the dependence on cation combination and chain length of the carboxylate ion. These investigations were made to explore the use of the glasses as host media for the release of agrochemical and other compounds with biological activity. It has been shown that Culex quinquefasciatus gives a positive ovipositional response to pheromone that is released from doped glasses over an extended time period. An investigation of the glass structure and the environment it provides for guest materials was undertaken using selected analyses. The structures of zinc carboxylates were determined by X-ray crystallography to provide information pertinent to the nature of the coordination of zinc in these glasses. Organotin compounds were dissolved in carboxylate glasses and studied by 119Sn NMR and Mossbauer spectroscopy. Anion exchange reactions readily occurred in the melts; there was also evidence of Sn-C bond cleavage with certain species. The potential of using Mossbauer spectroscopy as a probe into the glass "structure" is discussed.

The effect on conductivity of progressively substituting foreign alkali for host alkali in a series of lithium aluminoborate glasses has been studied. The shape of the conductivity isotherm in the dilute foreign alkali region was found to be the same for both Na+ and K+ dopants. Assuming a 'regular interstitialcy model' for ionic conduction conductivity data for a variety of glasses were subjected to isothermal analysis, allowing concentrations of mobile species and mobilities to be calculated. Conductivity changes were found to be largely attributable to changes in mobility, the concentration term remaining remarkably constant. The a.c. behaviour of aluminoborate glasses has also been studied and modulus spectra fitted using the Kohlrausch-Williams-Watts function for various beta-values. Decreasing the total alkali content and substituting foreign alkali for host alkali was observed to cause some narrowing of the modulus, mixed-alkali glasses behaving much as though only 'host' cations were present. 'Microscopic' activation energies (E_a) have been calculated from beta-values (Ea=beta Ead.c.). These are found to follow the trend in experimentally observed activation energies indicating that the mixed alkali effect occurs as the result of decreases in both long- and short-range ionic mobilities. A cluster-bypass model has been proposed in an attempt to reconcile the above results. The model assumes that the mobile species are to be found in a tissue material surrounding the clusters. A brief examination of the site preferences of spectroscopic probe ions (T1+ and Pb2+) in mixed cation glasses by u.v. spectroscopy indicated a dependence of the frequency of the absorption band on the reagents used in glass preparation. This result is thought to point towards some structural effects persisting in the melt which in turn may be important with respect to cluster formation in the glass.

In transparent glass, colour occurs through the absorption of certain wavelengths of light, and transmission of other wavelengths. In thicker sections of glass, more light is absorbed than in thinner sections, making the thicker sections appear darker, and sometimes a different hue. This phenomenon is called volume colour by Joseph Albers, and together with the optical properties of glass as a denser material than air, leads to remarkable possibilities for glass artists, to work with form to achieve light accents and/or different hues in solid object made from a single transparent glass colour. Artists in the Czech republic have explored this potential in cast glass since the 1960s, working directly with colour factories, and passing on gained knowledge through teaching. Elsewhere, it is difficult for artists to explore these possibilities for two reasons: Firstly, the lack of literature on volume colour, and the difficulty of translating theoretical information on optics into practical application. Secondly, on the practical side, it is unusual for artists to work with factories to develop their glass colours. Instead, colours are available in a limited range of hues, and casting colours are developed for small to medium sized objects around 5 cm thickness, therefore often appear very dark or black when used for larger solid casts of more than 10 cm thickness. To explore the relationship between colour, form and light in glass sculpture, artists need to be in control of colour hue and value. To achieve control, they have to either work with a factory, or colour their own glass. This research contributes to the practice of kiln casting through the development of methods to produce homogenous transparent colours in a studio environment, using ceramic crucibles in a kiln. Visual and written guidelines about basic colour results using single colouring agents provide a starting point for development of bespoke hues and densities. Drawing on physics texts and through a thorough study of existing glass sculpture, the optical properties of glass are explained in relation to practical application.

Jamming is a physical process which is both easy to describe and incredibly difficult to understand. One such difficulty is that mechanical treatments of jamming focus on pressure, force, stress, and strain, which are identically zero below jamming, making it hard to differentiate systems whcih which are near or far from the transition. Instead, I introduce a geometric framework based on the Voronoi tesselation which treats all of phase space on an equal footing. This work will show that the jamming transition can be seen entirely through the geometry of the local environment of particles encoded in the Voronoi tesselation, and it will build the framework for an as yet undefined field theory for jamming.

The U.S. glass industry is a $28 billion enterprise and millions of tons of glasses are melted each day by different heating techniques, such as conventional oil fired furnaces or via electrical heating. The share of electrical heating is bound to rise steadily because it is cleaner and more energy efficient. Due to this situation molybdenum will play a significant role in electrical glass melting, since it is the most frequently used electrode material to deliver the electricity into the glass melts. Although it has a high melting point, high electrical and thermal conductivity and a low coefficient of expansion, molybdenum electrodes fail because of lack of sustainability during the glass melting process. Melt reaction with electrodes is the fundamental barrier to higher melting temperatures. Glass manufacturers have suggested that the need for better performance of molybdenum electrodes will see a rapid advancement in the use of electric heating system in the U.S. This work first focused on post-mortem analysis on used molybdenum electrodes with and without the current load in order to establish failure mechanisms for molybdenum during glass melting. It was determined that service life of molybdenum electrodes are limited by poor oxidation and corrosion resistance of molybdenum with redox reactions. Various studies have shown that the failure mode for molybdenum electrodes is a complex phenomenon. It depends on chemical composition of the electrode, current density and frequency, and chemical composition of the glass melt, specifically polyvalent ions that may be present in the melt. In this work, the MoSiB coating was validated as a promising protection for molybdenum from oxidation attack. Several molybdenum and molybdenum based-alloy electrodes were tested in different molten glasses in the remelter furnace to optimize the structural characteristics that are needed in Mo electrodes. Moreover, the quantitative data and fundamental knowledge gained in this work is being applied for molybdenum electrode production to extend its service life and also improve its quality.

This practice-based research addresses internal form in cast glass. That is, ink- like imagery, which is wholly contained within clear, colourless glass. For the purposes of this project, ‘ink’ refers to liquid ink as is used in Chinese brush painting and calligraphy rather than to ink applications such as those used in print media. The aim is not to use ink itself. Rather, it is to emulate ink, rendered inside glass, while exploring the material similarities between the two media, including their liquid properties and their ability to be worked opaque or translucent. The project examines the interface between control and chance; where the artistic process ends and the unique properties of glass take over and are governed by heat, time and gravity. It also addresses the transformation of two- dimensional line drawing and ink wash into the third dimension. My research question is how the kiln and furnace casting processes can best be exploited to render the fluid, gestural and expressionistic immediacy of brush and ink painting, three-dimensionally, in solid glass. Following 14 years of studying and making art in Korea (1997‒2003) and China (2003‒2010), I have developed an affinity for brush and ink painting and, more specifically, for Chinese Grass script calligraphy and traditional landscape. This project aims to explore various methods of capturing apparent gesture and spontaneity in cast glass, in the form of ‘ink’ abstractions that evoke these styles of Chinese painting. My methodology includes identifying and isolating the elements that characterise Chinese brushwork in calligraphy and landscape painting, which are intimately linked fine art forms in China. Studio tests include manipulating different types of glass to create a dynamic, rhythmic, assured and graceful ink aesthetic, interpreted in the third dimension. I use flameworked inclusions to explore ink-like line and experiment with glass powders to evoke different intensities of ink wash. All tests are recorded in detail and are used to anticipate and loosely control glass movement. My research into Chinese brushwork characteristics is used to identify a framework within which the studio work sits. The variety, order and combination of techniques used to create the work constitute original knowledge in the field of cast glass. My method for reinterpreting the characteristics of Chinese painting, including line quality, ink wash, composition and balance, embedded three-dimensionally within the framework of cast glass, also contributes new knowledge. Based on systematic research and analysis, the terms ‘casting’, ‘moulds’, ‘spontaneity’ and the ‘third dimension’ are examined and defined anew.

Everything that happens takes place somewhere, in a particular physical or cultural space. The character of a place is constituted, its distinctive timbre generated, by the constellations of events occurring in it and how those blend, interweave and play out over time. Such textural qualities infuse and inform our experience of places, they shape our ‘knowing’ at a visceral level that goes unnoticed in our ordinary lives. Our conscious awareness of the places and spaces we visit and inhabit is filtered by our interests, honed through habit, marshalled and constrained by conventional perceptions of what matters. The contingent qualities of places beyond the purposes they serve for us are rarely considered and harder to attend to. But if we want to appreciate the world in its own right, not just in ours, finding ways to do so seems worthwhile. Artists adopt a variety of strategies to penetrate beyond the more obvious features of place. Some seek estrangement through the systematic application of arbitrary rules, others through strenuous efforts of will. I use ways of looking and thinking that are grounded in my experience of training as a glassmaker and developed using photography and video. My approach employs a broadly defined ‘glass sensibility’ that encompasses both the physical abilities of glass to mediate visual perception and their metaphorical correlates as shapers of ideas. My mode of enquiry is the essay, a flexible and open-­‐ended form of reflexive investigation that is highly attentive and responsive to its subject matter, and follows where that leads. But unlike other essayists who pursue their trains of thought in lines of words, my attempts at understanding are more visual. I explore my chosen places -­‐ a bus, a train, a road junction, a kitchen, a forest, a park, a desert -­‐ by spending periods of time in them doing whatever being there generally involves whilst also noticing how things happen and taking photographs. What I’m looking out for are telling facets, small examples of conjunctions of events which I can somehow ‘cut and polish’ at the critical angle that aids transparency, letting light in on the intrinsic character of the place and making it sparkle. The substantive outcomes of these essays are new awarenesses that bypass language; but each is accompanied and supported in the thesis by a textual account of how it came about. The contributions made by this thesis are three-­‐fold: It expands the repertoire of strategies for appreciating place, develops a novel understanding of how glass-­‐based thinking may inform processes of exploration and offers a new, more literal, version of essayistic reflection.

The visual system generates the perception of a world of meaningful three - dimensional objects from a stream of retinal signals – in the psychologist Richard Gregory’s words ’images in the eyes’. When this perception is consistent with information from other sources such as the ears and the muscles that guide movement, all is well and we are almost entir ely unaware of this process. But when it is not, we see illusions. To adopt Gregory’s phrase, ‘strange phenomena that challenge our sense of reality’ 1 . The project is inspired by the work of the German artist Ludwig Wilding (1927 – 2010), who refined appr oaches to the everyday phenomenon of moiré interference patterns to generate dramatic illusions of depth and movement in shallow box frame structures. 1 Gregory Richard L. 1990. Seeing Through Illusions . Oxford: Oxford University Press. p186 Based on the principle that the intersection of two sets of parallel lines generates the appearance o f a third set of lines, or moiré bands, Wilding’s innovation lay in the discovery that, by introducing a shallow space between the two layers of printed lines and by tilting and rotating them , the size and orientation of the se moiré bands can be manipulate d to produce converging contours and texture gradients that are perceived by the visu al system as forms in depth. This thesis builds on these observations to investigate the potential of the material and optical qualities of glass in combination with moiré interference effects to generate inconsistencies between th e images in the eyes and the objects that produce them, creating illusions of space.