Emily T. Nienhuis

Emily T. Nienhuis
Pacific Northwest National Laboratory | PNNL

Ph.D. Materials Science and Engineering

About

18
Publications
1,531
Reads
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58
Citations
Citations since 2016
18 Research Items
56 Citations
20162017201820192020202120220102030
20162017201820192020202120220102030
20162017201820192020202120220102030
20162017201820192020202120220102030
Additional affiliations
June 2020 - present
Pacific Northwest National Laboratory
Position
  • PostDoc Position
Education
August 2016 - May 2020
Washington State University
Field of study
  • Materials Science and Engineering
August 2012 - May 2016
Northwestern College
Field of study
  • Chemistry

Publications

Publications (18)
Article
Glasses with compositions xNaCl-(50-x/2)K2SO4-(50-x/2)ZnSO4, x = 0 to 30 (in mol%), were characterized via vibrational spectroscopy and X-ray pair distribution function (xPDF) analysis. The xPDF's were modeled using Empirical Potential Structure Refinement (EPSR). From the modeled xPDF, the deconvoluted xPDFs were obtained along with cation-anion c...
Article
In this study, the effect of Ti4+ on the structure of nepheline glass (NaAlSiO4) is investigated as SiO2 is systematically replaced with TiO2. Traditionally, TiO2 is considered to be a nucleating agent for silicate crystallization but can also be incorporated into the glass network in relatively large amounts as either a network former or modifier...
Article
Full-text available
The structures of a series of Na2O–FeO–Fe2O3–SiO2 melts with Si/Fe = 1, 2, or 3 have been characterized via synchrotron X-ray total scattering using aerodynamic levitation, a containerless technique, paired with laser heating. The melt structure has been simulated using empirical potential structure refinement (EPSR) based on X-ray scattering data...
Article
In alkali aluminosilicate glasses, additions of 4+ cations like Zr and Ti are often added to promote crystallization. In this study, Zr, Ti, or Sn are progressively substituted for Si in nepheline (NaAlSiO4) glass to determine their impact on the crystallization behavior. For glasses homogeneous on quenching, up to NaAlZr0.075Si0.925O4, NaAlSn0.100...
Article
The underlying mechanism by which tetrahedrally-coordinated aluminate solutions species react to precipitate octahedrally-coordinated gibbsite is unknown. Sodium aluminate solutions provide the opportunity to investigate the role of the solution speciation and local structures in this reaction as their metastability can be controlled by varying the...
Article
Full-text available
There is wide industrial interest in developing robust models of long‐term (>100 years) glass durability. Archeological glass analogues, glasses of similar composition and alteration conditions to those being tested for durability, can be used to evaluate, and inform such models. Two such analogue glasses from a 1500‐year‐old vitrified hillfort nea...
Article
Recent interest in the crystal structure of natrophosphate (Na7FPO4·19H2O) has sought to better understand the propensity of this phase to vary in composition through either alteration of the fluoride/phosphate ratio or subspeciation of phosphate (PO43−) into hydrogen phosphate (HxPO43−x). To address questions brought up in the analysis of the solu...
Article
This study evaluated zeolite-based sorbents for iodine gas [I2(g)] capture. Based on the framework structures and porosities, five zeolites, including two faujasite (FAU), one ZSM-5 (MFI), one mesoMFI, one ZSM-22 (TON), as well as two mesoporous materials, were evaluated for I2(g) capture at room temperature and 150 °C in an iodine-saturated enviro...
Article
Full-text available
Non-ideal thermodynamics of solid solutions can greatly impact materials degradation behavior. We have investigated an actinide silicate solid solution system (USiO 4 –ThSiO 4 ), demonstrating that thermodynamic non-ideality follows a distinctive, atomic-scale disordering process, which is usually considered as a random distribution. Neutron total...
Article
Aluminate salts precipitated from caustic alkaline solutions exhibit a correlation between the anionic speciation and the identity of the alkali cation in the precipitate, with the aluminate ions occurring either in monomeric (Al(OH)4–) or dimeric (Al2O(OH)62–) forms. The origin of this correlation is poorly understood as are the roles that oligome...
Article
Full-text available
Understanding the origin of reactive species following ionization in aqueous systems is an important aspect of radiation–matter interactions as the initial reactive species lead to production of radicals and subsequent long-term radiation damage. Tunable ultrafast X-ray free-electron pulses provide a new window to probe events occurring on the sub-...
Article
Fluorine and other halides commonly exist in nuclear waste forms, and due to their volatile nature, halide retention poses an issue affecting waste loading during vitrification. The compositional effect on fluorine incorporation in aluminosilicate glasses is investigated through molecular dynamics simulations. Oxygen and fluorine coordination numbe...
Article
Nitrite (NO2−) is a prevalent nitrogen oxyanion in environmental and industrial processes, but its behavior in solution, including ion pair formation, is complex. This solution phase complexity impacts industries such as nuclear waste treatment, where NO2− significantly affects the solubility of other constituents present in sodium hydroxide (NaOH)...
Article
Four different rare-earth oxyapatites of Ca2RE8(SiO4)6O2 (RE = Pr, Tb, Ho, Tm) were synthesized using a solution-based method followed by drying, calcination, and high-temperature sintering in air. X-ray powder diffraction and Raman spectroscopy were performed on the synthesized oxyapatites. The RE oxyapatites crystallize in the hexagonal space gro...
Article
This study seeks to understand the low temperature reactions of the salt phase that occur during the vitrification of Hanford Low Activity Waste (LAW). Salts (such as nitrates, sulfates, carbonates, halides, etc.) play a key role in these low temperature reactions as they sequentially melt, decompose, and volatilize during batch-to-glass conversion...
Article
Greigite (Fe3S4) particles, with strong ferrimagnetic behavior, have been found to have desirable uses in the areas of biomedical and environmental applications. Size-dependent magnetic properties of greigite can play a crucial role in efficiency of its applications. This study reviews two synthetic approaches to producing such particles. The metho...
Article
Reactions of alkali salts (nitrates, sulfates, carbonates, halides, borates) play a key role in the low temperature feed conversion occurring at the cold cap during processing of Hanford Low Activity Waste (LAW) glass melters. An alkali salt phase can sometimes form, and preferentially incorporate radionuclides of Cs, Cl, I, and Tc. During melting...

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