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Showing 1 to 20 of 474 for “"glasses"”.
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Non-silicate porous glasses obtained by the leaching of borate-rich glasses
Glasses of the composition Na₂O-B₂O₃-X-Y and Na₂O-B₂O₃-Al₂o₃-X-Y were made where X and Y are two of the oxides CeO₂, HfO₂, ThO₂,Y₂O₃,ZrO₂ or Ga₂O₃. The glasses were either quenched or heat treated to promote phase separation and/or crystallization. The materials were subsequently leached in …
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Quantum Theory of Glasses
The quantum excitations in glasses have long presented a set of puzzles for condensed matter scientists. A common view is that they are largely disordered analogs of elementary excitations in crystals, supplemented by two level systems which are chemically local entities coming from disorder. This …
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Microplasticity in metallic glasses
Metallic Glasses (MGs) are amorphous metallic alloys with exceptional mechanical and physical properties. Like all good things, this class of materials comes with its own problems, in this case (i) a lack of ductility, (ii) degradation in properties over time due to aging, and (iii) abrupt and …
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Crystallisation of PFA glasses
Glasses with various compositions, falling in the CaO-AI20rSi02 and MgO-CaOAI20rSi02 systems were made, using pulverised fuel ash and silica, hydrated lime, kaolin and magnesium carbonate. Titania or ferric oxide and chromia were used as nucleants. Various crystallisation heat treatments were …
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Studies in semiconducting glasses
Thesis: M.S., Massachusetts Institute of Technology, Department of Metallurgy, 1960
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Fundamental studies on ionomer glasses
… relationships were studied in glasses of the type used to produce glass lonomer dental cements. These materials are currently being developed as a bone cement in joint replacement surgery. Initially, a simple quaternary (25i02-Al203-CaO-CaF2) glass was produced and was found to …
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The production of colored glasses
Made available in DSpace on 2016-11-09T23:48:08Z (GMT). No. of bitstreams: 2 5994803_opt.pdf: 8271389 bytes, checksum: 166bb3eec61a39ce3af6fb60b5335e5d (MD5) license.txt: 4183 bytes, checksum: 1dcc2037833d76bede73d5717587543b (MD5) Previous issue date: 1916
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Thermomechanical Processing of Metallic Glasses
Depending on its thermal and kinetic history, a metallic glass (MG) of a given composition can show a wide range of energetic states. One central parameter determining the initial state of a glass is the cooling rate used to form it upon quenching from the melt. A faster cooling rate will give rise …
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Molecular modelling of polymeric glasses
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1985.
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Dynamical perspective of stability in glasses
Glasses are intrinsically out-of-equilibrium materials, and their stability plays a central role in determining both their physical properties and their technological performance. This Thesis investigates how glass stability influences microscopic dynamics over a wide range of timescales, from …
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Shear-band structure in metallic glasses
Metallic glasses (MGs) are amorphous alloys that possess exceptional mechanical properties compared to their crystalline counterparts. The fundamental problem that currently prevents the use of MGs as reliable structural materials is the lack of understanding of how their structure evolves as a …
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Nonequilibrium behavior of polymeric network glasses
… behavior in-network and pseudo network polymeric glasses has focused on linear and network epoxy systems, semicrystalline PET, and SBS and PC-PSX block copolymers. The aging behavior of polymers within each of these three classes was compared, and certain relationships between structure and aging …
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Azobenzene-functionalized molecular glasses for holographic applications
… of azobenzene-containing molecular glasses as well as their application as functional materials in specific holographic experiments. By utilizing a modular design principle, we were able to fine-tune their physical and photo-physical properties and optimize the molecular structure in …
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Crystallization of magnesium sialon liquids and glasses
… annealing of quenched MgSiAlON (3M/4X) glasses containing precipitated B- S i3 N4 / B 1 s i a l on nuclei which must be present for epitaxial nucleation and growth to proceed. The degree of B11 crystallization which can be achieved is sensitive to both composition and impurity levels and …
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Modified chalcogenide glasses for optical device applications
… modification of gallium lanthanum sulphide (GLS) glasses. Firstly the addition of transition metal ions as dopants is examined and their potential for use as active optical materials is explored. It is also argued that the spectroscopic analysis of transition metal ions is a useful tool for …
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Modified chalcogenide glasses for optical device applications
… modification ofgallium lanthanum sulphide (GLS) glasses. Firstly the addition of transition metal ionsas dopants is examined and their potential for use as active optical materials is explored.It is also argued that the spectroscopic analysis of transition metal ions is a useful toolfor …
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Internal friction of mixed-alkali silicate glasses
"The mixed alkali effect in silicate glasses was examined from internal friction measurements made over the temperature range from -190 to 500⁰C and at a frequency of 0.4 Hz. Supplemental measurements of the activation energy for the different internal friction peaks, dynamic shear modulus, …
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