Greg F. Piepel

Bio: Greg F. Piepel is an academic researcher from Pacific Northwest National Laboratory. The author has contributed to research in topics: Liquidus & Linear model. The author has an hindex of 11, co-authored 24 publications receiving 268 citations. Previous affiliations of Greg F. Piepel include Battelle Memorial Institute.

Uniform Designs for Highly Constrained Mixture Experiments

Abstract: Two number-theoretic methods are introduced for generating space-filling designs for constrained mixture experiments defined by single- and multiple-component constraints. The methods are illustrated for a simple 3-component mixture problem and a more c..

Mixture Experiment Techniques for Reducing the Number of Components Applied for Modeling Waste Glass Sodium Release

Abstract: Statistical mixture experiment techniques were applied to a waste glass data set to investigate the effects of the glass components on Product Consistency Test (PCT) sodium release (NR) and to develop a model for PCT NR as a function of the component proportions. The mixture experiment techniques indicate that the waste glass system can be reduced from nine to four components for purposes of modeling PCT NR. Empirical mixture models containing four first-order terms and one or two second-order terms fit the data quite well, and can be used to predict the NR of any glass composition in the model domain. The mixture experiment techniques produce a better model in less time than required by another approach.

Modeling methods for mixture-of-mixtures experiments applied to a tablet formulation problem.

Abstract: During the past few years, statistical methods for the experimental design, modeling, and optimization of mixture experiments have been widely applied to drug formulation problems. Different methods are required for mixture-of-mixtures (MoM) experiments in which a formulation is a mixture of two or more "major" components, each of which is a mixture of one or more "minor" components. Two types of MoM experiments are briefly described. A tablet formulation optimization example from a 1997 article in this journal is used to illustrate one type of MoM experiment and corresponding empirical modeling methods. Literature references that discuss other methods for MoM experiments are also provided.

Liquidus temperatures of HLW glasses with zirconium-containing primary crystalline phases

Abstract: Three empirical models are investigated for predicting liquidus temperatures ( T L ) as a function of glass composition for high-level waste (HLW) glasses with zirconium-containing primary crystalline phases. The three models are: (1) first-order multiple regression, (2) first-order single regression, and (3) second-order multiple regression. For each of two HLW data sets and their union, the models were developed using least squares regression on data from glasses with any zirconium-containing primary phase, and for the subset of glasses with zircon (ZrSiO 4 ) as the primary phase. The fitted models, evaluations of their performances, and interpretations of results are presented. The first- and second-order models fit very well for four of the six combinations of data set (A, B, A + B) and primary phase (zircon, zirconium-containing), and reasonably well for the other two combinations. For the composition regions and primary phases studied, T L is: (i) increased by ZrO 2 , Al 2 O 3 , and MgO, (ii) decreased by Na 2 O and Li 2 O, and (iii) moderately to negligibly affected by SiO 2 , B 2 O 3 , and CaO.

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

Abstract: Liquidus temperatures (TL) were measured for high-level waste (HLW) borosilicate glasses covering a Savannah River composition region. The primary crystallization phase for most glasses was spinel, a solid solution of trevorite (NiFe2O4) with other oxides (FeO, MnO, and Cr2O3). The TL values ranged from 859 to 1310°C. Component additions increased the TL (per mass%) as Cr2O3 261°C, NiO 85°C, TiO2 42°C, MgO 33°C, A12O3 18°C, and Fe2O3 18°C and decreased the TL (per mass%) as Na2O −29°C, Li2O −28°C, K2O −20°C, and B2O3 −8°C. Other oxides (CaO, MnO, SiO2, and U3O8) had little effect. The effect of RuO2 is not clear.

Statistical Models in Engineering

Abstract: Statistical models in engineering , Statistical models in engineering , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Inertization and reuse of waste materials by vitrification and fabrication of glass-based products

Abstract: Vitrification is widely accepted as the most safe process for treating hazardous wastes and converting them into leach-resistant materials. In this paper a review of the current and emerging waste vitrification technologies is reported. Analysis of different methods of vitrification, according to physical state and composition of the waste, can offer a guideline for process selection. Moreover, the most recent studies on vitrification of various types of industrial and civil wastes and their further transformation in useful marketable products are presented and discussed.

Understanding Glass through Differential Scanning Calorimetry

Abstract: Differential scanning calorimetry (DSC) is a powerful tool to address some of the most challenging issues in glass science and technology, such as the nonequilibrium nature of the glassy state and ...

Confessions of a pragmatic statistician

Abstract: Summary. The paper reflects on the author’s experience and discusses how statistical theory, sound judgment and knowledge of the context can work together to best advantage when tackling the wide range of statistical problems that can arise in practice. The phrase ‘pragmatic statistical inference’ is introduced.

Toward Understanding the Effect of Low-Activity Waste Glass Composition on Sulfur Solubility

Abstract: The concentration of sulfur in Hanford low-activity waste (LAW) glass melter feed will be maintained below the point where the salt accumulates on the melt surface. The allowable concentrations may range from near zero to over 2.05 wt% (of SO3 on a calcined oxide basis) depending on the composition of the melter feed and processing conditions. If the amount of sulfur exceeds the melt tolerance level, a molten salt will accumulate which may upset melter operations and potentially shorten the useful life of the melter. At the Hanford site, relatively conservative limits have traditionally been placed on sulfur loading in melter feed, which in turn significantly increases the amount of LAW glass that will be produced. Crucible-scale sulfur solubility data and scaled melter sulfur tolerance data have been collected on simulated Hanford waste glasses over the last 15 years. These data were compiled and analyzed. An empirical model was developed to predict the solubility of SO3 in glass based on 253 simulated Hanford LAW glass compositions. This model represents the data well, accounting for over 85% of the variation in data, and was well validated. The model was also found to accurately predict the maximum amount of sulfur in melter feed that did not form a salt layer in 13 scaled melter tests of simulated LAW glasses. The model can be used to help estimate glass volumes and make informed decisions on process options (e.g., scale of supplemental LAW treatment facility, and pretreatment facility performance requirements). The model also gives quantitative estimates of component concentration effects on sulfur solubility. The components that increase sulfur solubility most are Li2O > V2O5 > CaO ≈ P2O5 > Na2O ≈ B2O3 > K2O. The components that decrease sulfur solubility most are Cl > Cr2O3 > Al2O3 > ZrO2 ≈ SnO2 > Others (i.e., the sum of minor components) ≈SiO2. The order of component effects is similar to previous literature data, in most cases.