WorldCat Identities

Navrotsky, Alexandra

Overview
Works: 42 works in 142 publications in 2 languages and 3,922 library holdings
Genres: Conference papers and proceedings 
Roles: Author, Editor, Other
Classifications: QE371, 548.3
Publication Timeline
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Most widely held works by Alexandra Navrotsky
Structure and bonding in crystals by Michael O'Keeffe( Book )

14 editions published in 1981 in English and held by 547 WorldCat member libraries worldwide

Structure and Bonding in crystals
Microscopic to macroscopic : atomic environments to mineral thermodynamics by Susan W Kieffer( Book )

8 editions published in 1985 in English and held by 469 WorldCat member libraries worldwide

Physics and chemistry of earth materials by Alexandra Navrotsky( Book )

12 editions published in 1994 in English and held by 436 WorldCat member libraries worldwide

Nanoparticles and the environment( Book )

8 editions published in 2001 in English and held by 424 WorldCat member libraries worldwide

Thermodynamics of minerals and melts by R. C Newton( Book )

12 editions published in 1981 in English and held by 390 WorldCat member libraries worldwide

Perovskite : a structure of great interest to geophysics and materials science( Book )

14 editions published in 1989 in English and held by 282 WorldCat member libraries worldwide

Geochemistry of geologic CO₂ sequestration( Book )

4 editions published in 2013 in English and held by 170 WorldCat member libraries worldwide

Materials fundamentals of gate dielectrics by Alexander A Demkov( Book )

11 editions published between 2005 and 2011 in English and held by 115 WorldCat member libraries worldwide

Materials Fundamentals of Dielectric Gates treats materials fundamentals of the novel gate dielectrics that are being introduced into semiconductor manufacturing to ensure the continuous scaling of the CMOS devices
Festkörperthermodynamik by Hermann Schmalzried( Book )

15 editions published between 1975 and 1978 in German and Undetermined and held by 108 WorldCat member libraries worldwide

Experimental techniques for thermodynamic measurements of ceramics by Nathan S Jacobson( Book )

1 edition published in 1999 in English and held by 91 WorldCat member libraries worldwide

Perovskite materials : symposium held April 1-5, 2002, San Francisco, California, U.S.A.( Book )

4 editions published in 2002 in English and held by 83 WorldCat member libraries worldwide

Structure and bonding in crystals( Book )

5 editions published in 1981 in English and held by 14 WorldCat member libraries worldwide

Structure and bonding in crystals by Michael O'Keeffe( Book )

4 editions published in 1981 in English and held by 13 WorldCat member libraries worldwide

Structure/property relationships in fluorite-derivative compounds( )

1 edition published in 2009 in English and held by 0 WorldCat member libraries worldwide

A Comprehensive Study of the Solubility, Thermochemistry, Ion Exchange, and Precipitation Kinetics of NO3 Cancrinite and NO3 Sodalite (Project No. : 81959)( )

1 edition published in 2004 in English and held by 0 WorldCat member libraries worldwide

NO3 cancrinite and NO3 sodalite haves been found as a common sodium alumino-silicate forming in strongly caustic and alkaline aqueous solutions associated with radioactive High Level Waste (HLW) stored in many underground tanks and also in nuclear waste treatment facilities such as the Savannah River Site (SRS). The appearance of these phases have created very expensive problems in waste treatment plants by fouling process evaporators in the SRS waste processing facility. Therefore, in order to prevent their formation an assessment of the relative stability, formation kinetics, and the ion-exchange characteristics of these two phases in HLW solutions needs to be investigated. The goals of this project are to: (1) Develop a robust equilibrium thermodynamic framework to accurately describe the formation of NO3 cancrinite and NO3 sodalite. (2) Provide quantification and characterization of the solid precipitation rates through long-term batch kinetic experiments and novel analytical techniques. (3) Investigate the partitioning and ion exchange properties of these zeolitic phases with respect to radionuclides and RCRA metal species. This also includes compositional and structural characterization of ion exchanged solids elucidate the exchange properties of these phases
Comprehensive Study of the Solubility, Thermochemistry, Ion Exchange, and Precipitation Kinetics of NO3 Cancrinite and NO33 Sodalite( )

1 edition published in 2004 in English and held by 0 WorldCat member libraries worldwide

The precipitation of aluminosilicate phases from caustic nuclear wastes has proven to be problematic in a number of processes including radionuclide separations (cementation of columns by aluminosilicate phases), tank emptying (aluminosilicate tank heels), and condensation of wastes in evaporators (aluminosilicate precipitates in the evaporators, providing nucleation sites for growth of critical masses of radioactive actinide salts). In a collaboration between SNL and UCD, we have investigated why and how these phases form, and which conditions favor the formation of which phases. These studies have involved synthesis and characterization of aluminosilicate phases formed using a variety of synthesis techniques, kinetics of precipitation, structural investigations of aluminosilicate phases, thermodynamic calculations of aluminosilicate solubility, calorimetric studies of aluminosilicate precipitation, and a limited investigation of radionuclide partitioning and ion exchange processes (involving typical tank fluid chemistries and these materials). The predominant phases that are observed in the aluminosilicate precipitates from basic tanks wastes (i.e. Hanford, Savannah River Site ''SRS'' wastes) are the salt enclathrated zeolites: sodium nitrate, sodium carbonate and sodium hydroxide sodalite and cancrinite. These phases precipitate readily from the high ionic strength, highly basic solutions at ambient temperatures as well as at elevated temperatures, with or without the presence of an external Al and Si source (both are contained in the waste solutions), and upon interactions with reactive soil components such as clays
A Comprehensive Study of the Solubility, Thermochemistry, Ion Exchange, and Precipitation Kinetics of NO3 Cancrinite and NO3 Sodalite( )

1 edition published in 2003 in English and held by 0 WorldCat member libraries worldwide

NO3 cancrinite and NO3 sodalite haves been found as a common sodium alumino-silicate forming in strongly caustic alkaline aqueous solutions associated with radioactive High Level Waste (HLW) stored in many underground tanks and also in nuclear waste treatment facilities such as the Savannah River Site (SRS). The precipitation of alumino-silicate phases from caustic nuclear wastes has proven to be problematic in a number of processes in waste treatment facilities including radionuclide separations (cementation of columns by aluminosilicate phases), tank emptying (aluminosilicate tank heels), and condensation of wastes in evaporators (aluminosilicate precipitates in the evaporators, providing nucleation sites for growth of critical masses of radioactive actinide salts). Therefore, in order to prevent their formation an assessment of the relative stability, formation kinetics, and the ion-exchange characteristics of these two phases in HLW solutions needs to be investigated. The goals of this project are to: (1) Develop a robust equilibrium thermodynamic framework to accurately describe and predict the formation of NO3 cancrinite and NO3 sodalite. (2) Provide a comprehensive characterization of the solid precipitation rates and mechanisms using novel spectroscopic (e.g., NMR) and thermochemical techniques in conditions encountered in HLW waste solutions. (3) Characterize the precipitation kinetics of the aluminosilicates and study the effects of temperature and fluid composition. (4) Investigate the ion exchange capacity of these zeolitic phases with respect to radionuclides and RCRA metal species
Membranes for H2 generation from nuclear powered thermochemical cycles( )

1 edition published in 2006 in English and held by 0 WorldCat member libraries worldwide

In an effort to produce hydrogen without the unwanted greenhouse gas byproducts, high-temperature thermochemical cycles driven by heat from solar energy or next-generation nuclear power plants are being explored. The process being developed is the thermochemical production of Hydrogen. The Sulfur-Iodide (SI) cycle was deemed to be one of the most promising cycles to explore. The first step of the SI cycle involves the decomposition of H{sub 2}SO{sub 4} into O{sub 2}, SO{sub 2}, and H{sub 2}O at temperatures around 850 C. In-situ removal of O{sub 2} from this reaction pushes the equilibrium towards dissociation, thus increasing the overall efficiency of the decomposition reaction. A membrane is required for this oxygen separation step that is capable of withstanding the high temperatures and corrosive conditions inherent in this process. Mixed ionic-electronic perovskites and perovskite-related structures are potential materials for oxygen separation membranes owing to their robustness, ability to form dense ceramics, capacity to stabilize oxygen nonstoichiometry, and mixed ionic/electronic conductivity. Two oxide families with promising results were studied: the double-substituted perovskite A{sub x}Sr{sub 1-x}Co{sub 1-y}B{sub y}O{sub 3-{delta}} (A=La, Y; B=Cr-Ni), in particular the family La{sub x}Sr{sub 1-x}Co{sub 1-y}Mn{sub y}O{sub 3-{delta}} (LSCM), and doped La{sub 2}Ni{sub 1-x}M{sub x}O{sub 4} (M = Cu, Zn). Materials and membranes were synthesized by solid state methods and characterized by X-ray and neutron diffraction, SEM, thermal analyses, calorimetry and conductivity. Furthermore, we were able to leverage our program with a DOE/NE sponsored H{sub 2}SO{sub 4} decomposition reactor study (at Sandia), in which our membranes were tested in the actual H{sub 2}SO{sub 4} decomposition step
New Metal Niobate and Silicotitanate Ion Exchangers : Development and Characterization( )

1 edition published in 2003 in English and held by 0 WorldCat member libraries worldwide

This renewal proposal outlines our current progress and future research plans for ion exchangers: novel metal niobate and silicotitanate ion exchangers and their ultimate deployment in the DOE complex. In our original study several forms (including Cs exchanged) of the heat treated Crystalline Silicotitanates (CSTs) were fully characterized by a combination of high temperature synthesis and phase identification, low temperature synthesis and phase identification, and thermodynamics. This renewal proposal is predicated on work completed in our current EMSP program: we have shown preliminary data of a novel class of niobate-based molecular sieves (Na/Nb/M/O, M = transition metals), which show exceptionally high selectivity for divalent cations under extreme conditions (acid solutions, competing cations), in addition to novel silicotitanate phases which are also selective for divalent cations. Furthermore, these materials are easily converted by a high temperature in-situ heat treatment into a refractory ceramic waste form with low cation leachability. The new waste form is a perovskite phase, which is also a major component of Synroc, a titanate ceramic waste form used for sequestration of HLW wastes from reprocessed, spent nuclear fuel. These new niobate ion exchangers also shown orders of magnitude better selectivity for Sr2+ under acid conditions than any other material. The goal of the program is to reduce the costs associated with divalent cation waste removal and disposal, to minimize the risk of contamination to the environment during ion exchanger processing, and to provide DOE with materials for near-term lab-bench stimulant testing, and eventual deployment. The proposed work will provide information on the structure/property relationship between ion exchanger frameworks and selectivity for specific ions, allowing for the eventual ''tuning'' of framework for specific ion exchange needs. To date, DOE sites have become interested in on-site testing of these materials; ongoing discussions and initial experiments are occurring with Dr. Dean Peterman, Idaho National Engineering and Environmental Laboratory (INEEL) (location of the DOE/EM Waste Treatment Focus Area), and Dr. John Harbour, Savannah River Site (SRS). Yet the materials have not been optimized, and further research and development of the novel ion exchangers and testing conditions with simulants are needed. In addition, studies of the ion exchanger composition versus ion selectivity, ion exchange capacity and durability of final waste form are needed. This program will bring together three key institutions to address scientific hurdles of the separation process associated with metal niobate and silicotitanate ion exchangers, in particular for divalent cations (e.g., Sr2+). The program involves a joint effort between researchers at Pacific Northwest National Laboratory, who are leaders in structure/property relations in silicotitanates and in waste form development and performance assessment, Sandia National Laboratories, who discovered and developed crystalline silicotitanate ion exchangers (with Texas A & M and UOP) and also the novel class of divalent metal niobate ion exchangers, and the Thermochemistry Facility at UC Davis, who are world renowned experts in calorimetry and have already performed extensive thermodynamic studies on silicotitanate materials. In addition, Dr. Rodney Ewing of University of Michigan, an expert in radiation effects on materials, and Dr. Robert Roth of the National Institute of Standards and Technology and The Viper Group, a leader in phase equilibria development, will be consultants for radiation and phase studies. The research team will focus on three tasks that will provide both the basic research necessary for the development of highly selective ion exchange materials and also materials for short-term deployment within the DOE complex: (1) Structure/property relationships of a novel class of niobate-based molecular sieves (Na/Nb/M/O, M = transition metals), which show exceptionally high selectivity for divalent cations under extreme conditions (acid solutions, competing cations), (2) the role of ion exchanger structure change (both niobates and silicotitanates) on the exchange capacity (for elements such as Sr and actinide-surrogates) which results from exposure to DOE complex waste simulants, (3) thermodynamic stability of metal niobates and silicotitanate ion exchangers
 
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Audience level: 0.58 (from 0.51 for Materials ... to 0.87 for Festkörpe ...)

Physics and chemistry of earth materials
Alternative Names
Alexandra Navrotsky Amerikaans scheikundige

Alexandra Navrotsky amerikansk kemiker

Alexandra Navrotsky amerikansk kemist

Alexandra Navrotsky amerikansk kjemikar

Alexandra Navrotsky amerikansk kjemiker

Alexandra Navrotsky physical chemist in the field of nanogeoscience

Navrotsky, A.

Navrotsky, A. (Alexandra)

Languages
English (103)

German (13)

Covers
Materials fundamentals of gate dielectrics