Glasses Tech

The recovery and beneficiation of solid waste residues (bottom and fly ash) produced during incineration of municipal wastes are very important goals from the environmental and economic point of view. Some technologies allow not only to reduce the volume of incinerator waste but also to generate products of economic value by vitrification, devitrification, and ceramic processes. (more glasses…)

Submarine basaltic glasses from five widely separated sites on the Ontong Java Plateau (OJP) were analysed for major and volatile elements (H2O, CO2, S, Cl). At four of the sites (1183, 1185, 1186, 1187) the glass is from pillow basalt rims, whereas at Site 1184 the glass occurs as non-vesicular glass shards in volcaniclastic rocks. Glassy pillow rims from Site 1187 and the upper group of flows at Site 1185 have 8.3–9.3 wt% MgO compared with values of 7.2–8.0 wt% MgO for glasses from Sites 1183, 1184 1186, and the lower group of flows at Site 1185. Low-MgO glasses have slightly higher H2O contents (average 0.22 wt% H2O) than high-MgO glasses (average 0.19 wt%), with the exception of Site 1184, where low-MgO glasses have lower H2O (average 0.16 wt%). Average S concentrations are 910 ± 60 ppm for the high-MgO glasses v. 1030 ± 60 ppm for the low-MgO glasses. When compared with mid-ocean ridge basalt (MORB), the OJP glasses have lower S at comparable FeOT. (more glasses…)

Na K-edge X ray absorption near-edge structure (XANES) spectra for minerals and glasses were collected using synchrotron radiation. Na-K XANES is a good structural probe to determine the coordination state of this element in important minerals and glasses. From the XANES spectra on crystalline reference phases with different chemical environment, information can be obtained and compared with the structure of the minerals and glasses. (more glasses…)

Smooth muscle exhibits biophysical characteristics and physiological behaviors that are not readily explained by present paradigms of cytoskeletal and cross-bridge mechanics. There is increasing evidence that contractile activation of the smooth muscle cell involves an array of cytoskeletal processes that extend beyond cross-bridge cycling and the sliding of thick and thin filaments. We review here the evidence suggesting that the biophysical and mechanical properties of the smooth muscle cell reflect the integrated interactions of an array of highly dynamic cytoskeletal processes that both react to and transform the dynamics of cross-bridge interactions over the course of the contraction cycle. (more glasses…)

We argue that the intrinsic glassy degrees of freedom in amorphous solids giving rise to the thermal conductivity plateau and the “boson peak” in the heat capacity at moderately low temperatures are directly connected to those motions giving rise to the two-level-like excitations seen at still lower temperatures. These degrees of freedom can be thought of as strongly anharmonic transitions between the local minima of the glassy energy landscape that are accompanied by ripplon-like domain wall motions of the glassy mosaic structure predicted to occur at T g by the random first-order transition theory. (more glasses…)

Property and structure data from binary and ternary silicate and aluminosilicate melts and glasses often reveal simple and systematic relationships to composition and temperature. Properties whose dominant structural control is the abundance of fully polymerized Q4-species, exhibit smooth variations with silica content. Such properties include activation energies associated with transport. Properties that depend on the type and abundance of coexisting structural species in depolymerized melts, either show smooth functional relationships to melt polymerization, NBO/T, or exhibit pronounced minimum or maximum values at intermediate NBO/T-values. (more glasses…)

Molar absorptivity of the infrared (IR) fundamental OH-stretching vibration band at 3550 cm–1 was determined for rhyolitic glasses. Five obsidian samples, unheated and heated at 500–700 °C using an internally heated pressure vessel, were used to evaluate the dependence of the molar absorptivity and final quenched H2O speciation on H2O contents and temperature. Water contents of the obsidians were measured by Karl-Fischer titration first, then the amount of unextracted H2O was calibrated by IR (more glasses…)

AbstractThe low Re abundance in arc-type volcanic rocks characterized by high 187Os/188Os ratios is an unsolved puzzle of the 187Re-187Os isotope system, leaving a significant gap in our understanding of the evolution of the upper mantle–continental crust system. Here we report new observations of high Re concentrations in fresh, submarine-erupted—i.e., relatively undegassed—island arc–like volcanic glasses dredged from the eastern Manus Basin, offshore Papua New Guinea. (more glasses…)

A series of titanium silicate glasses along the composition joins TiO2–SiO2, TiO2–Na2SiO3, TiO2–K2SiO3 and TiO2–CaSiO3, has been examined using oxygen K-edge X-ray absorption near edge structure spectroscopy (XANES) confined to the near-surface region. Sharp pre-edge features in the spectra can be used to determine the Ti coordination in the glasses. The presence of [4]Ti is indicated by a pre-edge peak at ~534 eV while [5]Ti is indicated by a peak at ~533 eV. Titanium exists in all these glasses as [4]Ti and [5]Ti with no [6]Ti being present. For alkali-containing glasses the [5]Ti site becomes more prevalent with increasing TiO2. TiO2-K2SiO3 compositions contain a greater proportion of [4]Ti than comparable (more glasses…)

Gifted children are often Big Picture thinkers (Schultz & Delisle, 1997). Even as young children, they may ask profound questions and view life from the perspective of The Most Important Things: meaning, goodness, truth, spirituality, death, and the like. J. D. Salinger’s stories about the gifted and precocious Glass children offer a vivid, provocative, and very useful description of a spiritual Big Picture perspective on life. (more glasses…)