The Effect of Glass Composition Containing RE Oxide Waste Glass on Liquidus Temperature

MRS Advances ◽  
2016 ◽  
Vol 1 (63-64) ◽  
pp. 4221-4225
Author(s):  
S. Mohd Fadzil ◽  
P. Hrma
Keyword(s):  
Crystalline Phase ◽  
Liquidus Temperature ◽  
Glass Composition ◽  
Primary Phase ◽  
Borosilicate Glasses ◽  
Secondary Phases ◽  
Order Model ◽  
Composition Data ◽  
First Order ◽  
Wide Range

ABSTRACTThe liquidus temperature (TL) of rare earth (RE) was determined for alumino-borosilicate glasses for treating americium and curium that have been studied previously. Their work covers a wide range of glass composition with various crystalline phases as primary phase. Present work is aimed at understanding the effect of glass composition on TL for waste glasses designed for vitrifying RE oxides wastes. In a sufficiently narrow composition region, this effect can be represented by a first-order model fitted measured TL versus composition data. Test glasses were formulated by varying of component fractions one-at-a-time. The glasses contained SiO2, B2O3, and Al2O3 as glass formers and Nd2O3 with CeO2 as simulated RE waste. Twenty glasses were made to investigate crystallization as a function of temperature and glass composition. The primary crystalline phase was Ce-borosilicate (Ce3BSi2O10), secondary phases were Al-containing crystals (Al2O3 and Al10Si2O19), and crystalline CeO2. A first-order model was fitted to crystal fraction versus glass composition data. Generally, SiO2 and B2O3 tend to suppress crystallization, Al2O3 has little effect, and, as expected, RE components (Nd2O3 and CeO2) promote it. The correlation coefficient, R2, was 0.89 for the primary crystalline phase TL as a linear function of composition.

Liquidus Temperature of Spinel Precipitating High-Level Waste Glasses

1996 ◽  
Vol 465 ◽  
Author(s):  
M. Mika ◽  
M. J. Schweiger ◽  
J. D. Vienna ◽  
P. Hrma
Keyword(s):  
Mixture Models ◽  
Crystalline Phase ◽  
Liquidus Temperature ◽  
Glass Composition ◽  
High Level Waste ◽  
Hanford Site ◽  
High Iron ◽  
Negative Effect ◽  
High Level ◽  
Glass Viscosity

ABSTRACTThe liquidus temperature (TL) often limits the loading of high-level waste in glass through the constraint that TL must be at least 100°C below the temperature at which the glass viscosity is 5 Pa-s. In this study, values of TL for spinel primary crystalline phase were measured as a function of glass composition. The test glasses were based on high-iron Hanford Site tank wastes. All studied glasses precipitated spinel (Ni,Fe,Mn)(Cr,Fe)2O4 as the primary crystalline phase. TL was increased by additions of Cr2O3, NiO, Al2O3, Fe2O3, MgO, and MnO; while Li2O, Na2O, B2O3, and SiO2 had a negative effect. Empirical mixture models were fitted to data.

Liquidus Temperature Model for Hanford High-Level Waste Glasses with High Concentrations of Zirconia

1996 ◽  
Vol 465 ◽  
Author(s):  
J. V. Crum ◽  
M. J. Schweiger ◽  
P. Hrma ◽  
J. D. Vienna
Keyword(s):  
Crystalline Phase ◽  
Liquidus Temperature ◽  
Heat Treating ◽  
Primary Phase ◽  
High Level Waste ◽  
Mass Fractions ◽  
High Concentrations ◽  
Phase Glass ◽  
High Level ◽  
Temperature Furnace

ABSTRACTA study was conducted on glasses based on a simulated transuranic waste with high concentrations of ZrO2and Bi2O3 to determine the compositional dependence of primary crystalline phases and liquidus temperature (TL). Starting from a baseline composition, glasses were formulated by changing mass fractions of Al2O3, B2O3, Bi2O3, CeO2, Li2O, Na2O, P2O5, SiO2, and ZrO2, one at a time, while keeping the remaining components in the same relative proportions as in the baseline glass. Liquidus temperature was measured by heat treating glass samples for 24 h in a uniform temperature furnace. The primary crystalline phase in the baseline glass and the majority of the glasses was zircon (ZrSiO4). A change in the concentration of certain components (Al2O3, ZrO2, Li2O, B2O3 and SiO2) changed the primary phase to baddeleyite (ZrO2), while cerium oxide (CeO2) precipitated from glasses with more than 3 wt% CeO2. Zircon TL was strongly increased by Al2O3, Zrb2 and CeO2, and slightly by P2O5 and SiO2; decreased strongly by Li2O and Na2O and moderately by B2O3. A first-order model was constructed for TL as a function of composition for zircon primary crystalline phase glass.

First-Order Model of Free-Jet Hydrodynamic Evolution for Heat Transfer Prediction, Including Nozzle and Flow Rate Effects

2016 ◽  
Author(s):  
Ron S. Harnik ◽  
Herman D. Haustein
Keyword(s):  
Heat Transfer ◽  
Surface Tension ◽  
Free Surface ◽  
Velocity Profile ◽  
Rapid Development ◽  
Jet Impingement ◽  
Centerline Velocity ◽  
Order Model ◽  
First Order ◽  
Wide Range

Jet impingement flow is known to generate one of the highest single-phase heat transfer rates, with potential for micro-electronics cooling applications. Although free-surface jets have been studied extensively, existing models are either too complex for practical use or do not consider all relevant parameters, such as the impinging jet’s velocity profile. Recently the authors have shown that the stagnation zone heat transfer is dictated by the jet’s centerline velocity upon impingement, and that going between the limiting cases (uniform vs. parabolic profiles, laminar flow) corresponds to a two-fold increase in heat transfer. In the present study, which is motivated by cooling at micro-scales (predominantly laminar flows), this simplified analysis is extended leading to a first-order analytical approximation, which is valid not only for the limiting cases but over the entire profile range. Thereby, the development of the jet flow both in the nozzle (pipe-type) and subsequently during its flight (before impingement) is incorporated in this model over a broad range of parameters. For validation of the model, as well as for additional insight into the governing physics, direct numerical simulations were conducted. Through which it is shown that the jet’s velocity profile and its evolution during free “flight” are dependent on the level of the flow’s upstream development in the nozzle, both of which depend on a single self-similar scale: distance travelled normalized by the nozzle diameter and Reynolds number. This one-way coupling requires incorporation of both stages of development for an accurate description, as done in the present model. During pipe-flow, the first-order model employs a more-rapid development rate than during jet-flight (due to the additional pressure-driven flow) — converging to more complex, well-known models, within a few pipe diameters (for Re = 200 to 2300). During flight, the model describes velocity profile relaxation, which is dominated by viscous diffusion and assisted by jet contraction. Jet contraction is dependent on the emerging velocity profile and liquid-vapor surface tension. For most relevant conditions surface tension is negligible, under which the first-order model centerline velocity decay prediction agrees well with both present simulations and previous works. Thereby, the present work lays the foundation for a simpler, more useable model for predicting heat transfer under an impinging free-surface jet, over a wide range of conditions (various liquids, pipe-type nozzles of different lengths, flow-rates and nozzle-to-plate distances), as part of an ongoing study into micro-jet array heat transfer.

Liquidus Temperature of High-Level Waste Borosilicate Glasses With Spinel Primary Phase

1999 ◽  
Vol 608 ◽  
Author(s):  
Pavel Hrma ◽  
John Vienna ◽  
Jarrod Crum ◽  
Greg Piepel ◽  
Martin Mika
Keyword(s):  
Liquidus Temperature ◽  
Primary Phase ◽  
High Level Waste ◽  
Borosilicate Glasses ◽  
High Level

The Effects of Na2O, Al2O3, and 3203 ON HfO2 Solubility in Borosilicate Glass

1999 ◽  
Vol 556 ◽  
Author(s):  
L. L. Davis ◽  
L. Li ◽  
G. Darab ◽  
H. Li ◽  
D. Strachan ◽  
...  
Keyword(s):  
Borosilicate Glass ◽  
Glass Composition ◽  
Borosilicate Glasses ◽  
Initial Composition ◽  
Neutron Absorber ◽  
Reducing Conditions ◽  
Wide Range ◽  
Fourth Series

AbstractA single borosilicate glass composition has previously been shown to dissolve 10 and 25 mass% PuO2 under oxidizing and reducing conditions, respectively. A simplified version of this glass has been thoroughly investigated to determine the effect of increasing the alkali:aluminum ratio on the HfO2 solubility in borosilicate glasses. We are investigating HfO2 solubility because specific Pu wastes are being considered for disposal in glass, and Hf(IV) serves as a structural surrogate for Pu(IV) and as a neutron absorber in glass. Three series of base glasses were produced using the same initial composition, but varying the oxides B2O3, Al2O3, or Na2O one at a time. In a fourth series of the same initial composition, both Na2O and A12O3 were varied. Hafnia was added to these glasses and the mixture equilibrated for 2 hours: 1 hour at 1450°C after 1 hour at 1560°C. A wide range of HfO2 additions were made to the base glasses, and the solubility of HfO2 determined to within ±1 mass%. The highest solubility determined was 14 mol% (35 mass%) HfO2 in a low-Al glass. We conclude that increasing Na2O/Al2O3 increases the HfO2 solubility, and increasing the B2O3 content apparently has little effect on HfO2 solubility in the borosilicate glasses studied.

LIQUIDUS THERMO-BAROMETER FOR THE MODELING OF MAGNETITE — MELT EQUILIBRIUM

2018 ◽  
pp. 71-80
Author(s):  
N. S. Aryaeva ◽  
E. V. Koptev-Dvornikov ◽  
D. A. Bychkov
Keyword(s):  
Experimental Data ◽  
Liquidus Temperature ◽  
Vertical Structure ◽  
Maximum Error ◽  
Silicate Melt ◽  
System Of Equations ◽  
Wide Range ◽  
Basaltic Melts ◽  
Multidimensional Statistics

A system of equations of thermobarometer for magnetite-silicate melt equilibrium was obtained by method of multidimensional statistics of 93 experimental data of a magnetite solubility in basaltic melts. Equations reproduce experimental data in a wide range of basalt compositions, temperatures and pressures with small errors. Verification of thermobarometers showed the maximum error in liquidus temperature reproducing does not exceed ±7 °C. The level of cumulative magnetite appearance in the vertical structure of Tsypringa, Kivakka, Burakovsky intrusions predicted with errors from ±10 to ±50 m.

A first-order model of thermal lensing of laser propagation in the eye and implications for laser safety

2005 ◽  
Author(s):  
Robert J. Thomas ◽  
Rebecca L. Vincelette ◽  
Gavin D. Buffington ◽  
Amber D. Strunk ◽  
Michael A. Edwards ◽  
...  
Keyword(s):  
Thermal Lensing ◽  
Order Model ◽  
Laser Safety ◽  
First Order ◽  
Laser Propagation

Application of two approaches to model chlorine residuals in Severn Trent Water Ltd (STW) distribution systems

1997 ◽  
Vol 36 (5) ◽  
pp. 317-324 ◽  
Author(s):  
M.J. Rodriguez ◽  
J.R. West ◽  
J. Powell ◽  
J.B. Sérodes
Keyword(s):  
Distribution System ◽  
Distribution Systems ◽  
Treatment Plant ◽  
Residual Chlorine ◽  
Ann Model ◽  
Order Model ◽  
First Order ◽  
Chlorine Decay ◽  
Artificial Neural Network Ann ◽  
Key Parameter

Increasingly, those who work in the field of drinking water have demonstrated an interest in developing models for evolution of water quality from the treatment plant to the consumer's tap. To date, most of the modelling efforts have been focused on residual chlorine as a key parameter of quality within distribution systems. This paper presents the application of a conventional approach, the first order model, and the application of an emergent modelling approach, an artificial neural network (ANN) model, to simulate residual chlorine in a Severn Trent Water Ltd (U.K.) distribution system. The application of the first order model depends on the adequate estimation of the chlorine decay coefficient and the travel time within the system. The success of an ANN model depends on the use of representative data about factors which affect chlorine evolution in the system. Results demonstrate that ANN has a promising capacity for learning the dynamics of chlorine decay. The development of an ANN appears to be justifiable for disinfection control purposes, in cases when parameter estimation within the first order model is imprecise or difficult to obtain.

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