This paper is an investigation into the crossroads of traditional and contemporary glass craft techniques. Through innovative methods in the workshop I have set out to bring glass into the public sphere using the potential for handcraft in architecture.

Glass and the glass elements found thein way into almou all area sof human aktivity thanks to technological advances of the last 20 years. The are of construction i sof course no exeption, quite the contrary. These days it is difficult to imagine building without the glass element, whether it is a part of the interior or exterior. Yet the theory on this issue is at a very low level in the Czech Republic. The content of my work is static and dynamic analysis of structures of glass, when it is applied in practice, it will save money.

The Diploma thesis "Silesian Baroque Cut Glass in the collection of Museum of Decorative Arts in Prague" deals with the collection of Silesian Baroque cut glass at the Museum of Decorative Arts in Prague spanning from the last quarter of the 17th century to the third quarter of the 18th century. The thesis describes the technique of glass cutting and its history. It also deals with the beginnings of glass cutting in Silesia, which are associated with the Schaffgotsch family in the Hirschberger Valley. Worth mentioning is also the renowned glass cutter Friedrich Winter, who along with his glass workshop substantially influenced Silesian glass cutting in the following decades. The thesis also mentiones other well-known glass cutters, particularly Christian Gottfried Schneider. The chapters dealing with the development of the shape and ornament of Silesian Baroque cut glass are important for correct classification by periods and localities. A catalogue of selected objects from the collection of the Museum of Decorative Arts in Prague follows the first part of the thesis which comprises the text. Most of the catalogue's objects have not been published thus far or were often never presented in detail if they appeared in literature.

Archaeological investigations of Indian Key Historic State Park in the Florida Keys have uncovered a wide range of historical artifacts from throughout the nineteenth century that reveal how the site was reused and reoccupied through time. This thesis focuses on the glass component recovered from a house cistern complex (Feature F) and a warehouse (Features A and C) during the 1998 to 2002 field seasons. Glass artifacts range from a variety of bottle glass including alcohol bottles and proprietary medicines, to cut glass such as tumblers and decanters, to window glass. Feature F's analysis has shown that it maintained a primarily domestic nature despite having been reused by different groups at different times. Glass recovered from Feature F was primarily alcohol bottles, but large numbers of food bottles, medicines, and window glass was also found. The warehouse was used commercially and appears to have been continuously reused. The most abundant item recovered from the warehouse was window glass; however large quantities of alcohol bottle fragments were also recovered. Also included in the glass analysis is a study of window glass dating techniques using glass thickness. By using a formula originally developed by Randall Moir (1982), and following an example set by Grant L. Day (2001), I was able to illustrate a process for dating nineteenth century window glass that is fairly accurate for determining periods of transition, addition, and reconstruction to buildings occupied over long time periods. Comparison of the glass from these two features using window glass dating formulas and other comparative evaluations as well as dating and functional analysis is revealing useful information about each of these structures individually, as well as about activity on the island as a whole.

A laboratory scale study was carried out on a set of 6 borosilicate waste glasses made from simulated high-level nuclear waste. The test matrix was designed to explore the composition region suitable for the long-term geologic disposal of high-temperature-and high-waste-containing glasses. The glass compositions were selected to achieve maximum waste loading without a sacrifice in glass durability. The relationship between glass composition and chemical durability was examined. The qualitative effect of increasing B2O3 content on the overall waste glass leaching behavior has also been addressed. The glass composition matrix was designed by systematically varying the factors: %waste loading and (SiO2+Frit):B2O3 ratio, with (SiO2:Frit) ratio being held constant. In order to assess the chemical durability, the Product Consistency Test (ASTM C-1285) was performed. Under PCT protocol, crushed glass was allowed to react with ASTM type I water under static conditions. All leachate solutions were analyzed by the technique; Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES). A statistical regression technique was utilized to model the normalized release of the major soluble elements, Na, Si, and B, as a function of the individual as well as interactive chemical effects (B2O3, Al2O3, Fe2O3, MnO, SiO2, SrO, Na2O, B2O3*SiO2, B2O3*Al2O3, Fe2O3*Na2O, Al2O3*Na2O, and MnO*SiO2). Geochemical modeling was performed using the computer code EQ3/6 to: (1) determine the saturation states of the possible silicate minerals, a-cristobalite and chalcedony; and (2) predict the most stable mineral phase based on the mineral thermodynamic data. Mineral/water interactions were analyzed by representing the resultant glass data on a Na-Al-Si-O-H stability diagram.

Despite advancements in glass facade systems and rigorous building codes requirements, glass façades often sustain damage or breaches during extreme wind events. This study aims to establish a framework that identifies a multitude of characteristics in common glass façade systems that may contribute to performance of a buildings with glass facades during natural wind disasters. Through a comprehensive analysis of damaged structures, common characteristics susceptible to damage after such events were identified. These characteristics served as a catalyst to explore other characteristic that may affect the performance of a structure's facade during extreme wind events. The identified characteristics were categorized into three groups: architectural components, structural components, and environmental. Proposed quantifiable methods aim to obtain qualitative measurements of existing glass facades. In the end, this thesis contributes to the broader goal of understanding the performance of glass facades during extreme wind events. / Master of Science / Despite advances in building design and construction standards, glass on buildings remain vulnerable to damage during severe windstorms. This study aims to develop a system that identifies key factors that contribute to a building's glass façade system during natural disasters like hurricanes and tornadoes. By analyzing data from damaged structures, common characteristics were identified that are prone to damage during extreme wind events. These findings have led to explore other factors that may impact a facade's performance in such situations. These factors were categorized into three main groups: architectural features, structural elements, and environmental considerations. The proposed methods obtain a numeral value that is measured from existing structures. Ultimately, this research aims to improve the understanding of glass facades from challenges posed by severe weather events.

Master of Science

The effects of in situ Ti0₂ whisker reinforcement on mechanical and thermal properties of glass-ceramics in the Li₂O-Al₂0₃-P₂0₆-Si0₂ system were investigated. When Ti0₂ whiskers, having an average aspect ratio of 28, are precipitated from the glass-ceramic matrix, (Li_0.4,Ca_0.05)AI(Si_0.75,P_0.5)_04.5, flexural strength is improved from 72 to 134 MPa. Fracture toughness, K_Ic, is increased from the 1.1 to 1.6 MPa·m^1/2 due to crack deflection by the Ti0₂ whiskers. In situ Ti0₂ whisker-reinforced glass-ceramic exhibits rising fracture resistance, K_R, with increasing crack extension. The fracture resistance, K_R, is increased from 1.89 to 2.5 MPa·m^1/2 over the crack extension range range of 40 to 200 μm. The composite shows a narrow failure strength distribution compared to the glass-ceramic without Ti0₂ whisker precipitation. The coefficient of thermal expansion (CTE) changes from -2.8x10⁻⁷/"C to -1.7xl0⁻⁷/°C due to the precipitation of Ti0₂ phase which has a positive CTE (7.3xl0⁻⁶/°C). With the matrix composition, (Li_0.41,Mg_0.035)AI(Si₀0.48</sub>,P_O.52)O₄, a three-fold increase in flexural strength was observed with a Ti0₂ content of 12 wt%. CTE value of the composite increases linearly from a negative to a positive value with increasing Ti0₂ content up to 12 wt%. The in situ composite containing 8-10 wt% Ti0₂ exhibits near zero CTE values up to l000°C. / Ph. D.

No description available.

Borate glasses and glass-nano/microcrystal composite fabrication and investigations into their physical properties, have been interesting from their multifunctionalities view point. Certain borate structural units possess high hyperpolarizabilities and give rise to high nonlinear optical effects. High refractive index materials are important for photonic applications. Heavy metal oxide (Bi2O3) containing compounds have high refractive indices. Glasses embedded with wide band-gap semiconducting oxide crystals such as TiO2 received much attention due to their easy processing, stability and promising physical properties. Though TiO2 is used as nucleating agent to fabricate glass-ceramics of various phases, crystallization of TiO2 in glass matrices is difficult and the data are scarce in the literature. Therefore it was worth attempting to find glass compositions in which one can obtain TiO2 crystallization in large volume fractions. Towards this TiO2 crystallization was accomplished in BaO-TiO2-B2O3 glass matrix over wide composition ranges by tuning the concentration of BaO-TiO2 content in B2O3 network. The physical properties of these glasses of various compositions and glass-nanocrystal composites of TiO2 phase (anatase) were investigated. Interestingly BaO-TiO2-B2O3 glasses found to be hydrophobic in nature. The results obtained in the present research work are classified into five chapters apart from the Introduction, Materials and Methods chapters. Chapter 1 constitutes preface to oxide glasses, principles of glass formation and structural criteria followed by crystallization kinetics. In addition, principles of dielectric, optical and mechanical phenomena in glasses are discussed, since the present thesis focuses on the aforesaid physical properties. This chapter concludes with scope of the present thesis. Chapter 2 includes the detailed description concerning the fabrication techniques of materials under study and various characterization methods that have been employed at various stages of the present research work. The principles and experimental tools adopted for the structural and microstructural studies of materials were illustrated. Measurement techniques and experimental setup used to study physical parameters such as dielectric, optical, mechanical etc. were elaborated. Chapter 3 comprises structural, dielectric, electrical transport characteristics and optical studies of mixed alkali borate glasses in the 0.5Li2O-0.5M2O-2B2O3 (M=Li, Na and K) system. Transparent glasses in the Li2O-2B2O3 (LBO), 0.5Li2O-0.5Na2O-2B2O3 (LNBO) and 0.5Li2O-0.5K2O-2B2O3 (LKBO) were fabricated via the conventional melt quenching technique. Amorphous and glassy nature of the samples was confirmed via the X-ray powder diffraction and the differential scanning calorimetry, respectively. LKBO glass was found to have high thermal stability than that of LBO and LNBO. The frequency and temperature dependent characteristics of the dielectric relaxation and the electrical conductivity were investigated in the 100 Hz - 10 MHz frequency range. The relaxation and conductivity were rationalized using impedance and modulus formalism. Imaginary part of the electric modulus spectra was modelled using an approximate solution of Kohlrausch-Williams-Watts relation. The stretching exponent, β, was found to be temperature independent for LNBO glasses. Activation energies for conduction and relaxation process were calculated using the Arrhenius relation. The activation energy was found to be higher (1.25eV) for LKBO glasses than that of the other glass systems under study. This is attributed to the mixed cation effect. It has wide optical transmission window and optical band gap. Urbach energies were calculated for all these glasses. LBO, LNBO and LKBO glass compositions were found to crystallize in Li2B4O7, LiNaB4O7 and LiKB4O7 phases respectively upon heat treatment at appropriate temperatures. Transparent glass-micro crystal composites of LiKB4O7 were fabricated from LKBO glasses and found to be SHG active. BaO-TiO2-B2O3 Chapter 4 delineates the evolution of nanocrystalline TiO2 phase (Anatase) in BaO-TiO2-B2O3 (BTBO) glasses. Transparent colourless glasses in the ternary system were fabricated via conventional melt-quenching technique. The glasses with certain molar concentrations of BaO and TiO2 upon heat treatment at appropriate temperatures yielded nanocrystalline phase of TiO2 associated with the crystallite size in the 5-15 nm range. Nanocrystallized glasses exhibited high refractive index (no=2.15) at λ=543nm. These glasses were found to be hydrophobic in nature associated with the contact angle of 90o. These high index glass nanocrystal composites would be of potential interest for optical device applications. Crystallization kinetics of anatase phase in BTBO glasses were studied using non-isothermal Differential Scanning Calorimetry (DSC) at three different heating rates (10, 20 & 30 K/min). Scanning Electron Microscopy (SEM) carried out on heat treated (at 920 K) glasses confirmed bulk nucleation and three-dimensional growth. Johnson-Mehl-Avrami model could not be applied for this system suggesting considerable overlap of the nucleation and growth involving complex transformation process. However, modified Kissinger and Ozawa models were used to calculate the effective activation energy associated with anatase crystallization. The kinetic exponent n was found to be temperature dependent indicating the change in the crystallization mechanism. This is attributed to the high entropy fusion of anatase phase, fast crystallization rate and nano dimension of the anatase phase. Chapter 5 illustrates structural changes that occur in the x(BaO-TiO2)-B2O3 (x=0.25, 0.5, 0.75 &1 mol.) system on increasing the x apart from the details concerning some physical property correlations. Thermal stability and glass forming ability as determined by Differential Thermal Analysis (DTA) were found to increase with increasing BaO-TiO2 (BT) content. However, there was no noticeable change in the glass transition temperature (Tg). This was attributed to the active participation of TiO2 in the network formation especially at higher BT contents via the conversion of the TiO6 structural units into TiO4 units which increased the connectivity and resulted in an increase in crystallization temperature. Dielectric and optical properties at room temperature were studied for all the glasses under investigation. Interestingly, these glasses were found to be hydrophobic. The results obtained were correlated with different structural units present in the glass and their connectivity. These glasses exhibited low loss (tan δ≈0.002), frequency (10 kHz- 10 MHz) and temperature independent (or very weak temperature response) flat-dielectric response. Crossover temperature was encountered between flat response and Jonscher’s universal response. The cross-over temperature and cross-over energy barrier from flat dielectric response to Jonscher’s response was deduced for all the glasses in the present investigation. Electric modulus formalism was invoked to rationalize the relaxation phenomena. The observed dielectric response and conduction process in these glasses were attributed to the local vibration and switching of non-bridging oxygen ions in their potential cage and hopping over distributed energy barriers above the crossover temperature. Chapter 6 depicts the dielectric and mechanical properties of glasses embedded with TiO2 nanocrystals. BaO-TiO2-B2O3 glasses on subjecting to appropriate heat treatment temperature yielded TiO2 nano crystalline anatase phase. NMR studies carried out on the as-quenched glasses facilitated the estimation of fraction of tetrahedral and trigonal borate units. Poisson’s ratio and Young’s modulus were evaluated through theoretical expressions proposed by Makishima and Mackenzie. Nano-indentation and micro-indentation studies were carried out on the as-quenched glasses and glass-nanocrystal composites to examine mechanical characteristics. Estimated and indentation Young’s modulus of glasses were found to be in reasonable agreement. Hardness and Young’s modulus increased with increasing fraction of nano crystallites whereas fracture toughness was found to depend strongly on surface conditions. The results were corroborated by the structural units and particulates present in these glasses. Dielectric constant increased with increasing volume fraction of the nanocrystals which was rationalized via mixture rule. Chapter 7 describes the dielectric properties, electrical conduction and electric relaxation phenomena in 2Bi2O3-B2O3 (BBO) glasses followed by thier linear and nonlinear optical characteristics. Glasses in BBO system were obtained via melt-quenching technique. X-ray diffraction and differential scanning calorimetry were used to study the structural characteristics. Dielectric studies carried out on these glasses revealed near constant loss (NCL) response in the 1 kHz to 1 MHz frequency range at moderately high temperatures (300-450 K) accompanied by relatively low loss (tan δ=0.006, at 1 kHz & 300 K) and high dielectric constant (ε' =37, at 1 kHz & 300 K). The variation in AC conductivity with temperature at different frequencies showed a cross over from NCL response characterized by local ion vibration within the potential well to universal Jonscher’s power law dependence triggered by ion hopping between potential wells or cages. Thermal activation energy for single potential well was found to be 0.48±0.05 eV from cross over points. Ionic conduction and relaxation processes were rationalized by modulus formalism. The promising dielectric properties (relatively high ε' and low tan δ) of the BBO glasses were attributed to high density (93 % of its crystalline counterpart), high polarizability and low mobility associated with heavy metal cations, Bi3+. Optical band gap obtained for BBO glasses was found to be 2.6 eV. The refractive index measured for these glasses was 2.25±0.05 at λ=543 nm. Nonlinear refraction and absorption studies were carried out on BBO glasses using z-scan technique at λ=532 nm of 10 ns pulse width. The nonlinear refractive index obtained was n2=12.1x10-14 cm2/W and two-photon absorption coefficient was β=15.2 cm/GW. The n2 and β values of the BBO glasses were higher than that reported for high index bismuth based oxide glass systems in the literature. These were attributed to the high density, high linear refractive index, low band gap and two-photon absorption associated with these glasses. The electronic origin of large nonlinearities was discussed based on bond-orbital theory. Thesis ends with summary and conclusions followed by prospective views, though each chapter comprises conclusions associated with complete list of references. Patent, publications and conference proceedings that are listed below are largely based on the studies conducted as a part of the research work reported in the present thesis.