Analytical Plan for Roman Glasses

Roman glasses that have been in the sea or underground for about 1800 years can serve as the independent “experiment” that is needed for validation of codes and models that are used in performance assessment. Two sets of Roman-era glasses have been obtained for this purpose. One set comes from the sunken vessel the Iulia Felix; the second from recently excavated glasses from a Roman villa in Aquileia, Italy. The specimens contain glass artifacts and attached sediment or soil. In the case of the Iulia Felix glasses quite a lot of analytical work has been completed at the University of Padova, but from an archaeological perspective. The glasses from Aquileia have not been so carefully analyzed, but they are similar to other Roman glasses. Both glass and sediment or soil need to be analyzed and are the subject of this analytical plan. The glasses need to be analyzed with the goal of validating the model used to describe glass dissolution. The sediment and soil need to be analyzed to determine the profile of elements released from the glass. This latter need represents a significant analytical challenge because of the trace quantities that need to be analyzed. Both pieces of information will yield important information useful in the validation of the glass dissolution model and the chemical transport code(s) used to determine the migration of elements once released from the glass. In this plan, we outline the analytical techniques that should be useful in obtaining the needed information and suggest a useful starting point for this analytical effort

Formation of zinc oxide films using submicron zinc particle dispersions

The thermal oxidation of submicron metallic Zn particles was studied as a method to form nanostructured ZnO films. The particles used for this work were characterized by electron microscopy, x ray diffraction, and thermal analysis to evaluate the Zn-ZnO core shell structure, surface morphology, and oxidation characteristics. Significant nanostructural changes were observed for films annealed to 400 °C or higher, where nanoflakes, nanoribbons, nanoneedles, and nanorods were formed as a result of stress induced fractures arising in the ZnO outer shell due to differential thermal expansion between the metallic Zn core and the ZnO shell. Mass transport occurs through these defects due to the high vapor pressure for metallic Zn at temperatures above 230 °C, whereupon the Zn vapor rapidly oxidizes in air to form the ZnO nanostructures. The Zn particles were also incorporated into zinc indium oxide precursor solutions to form thin film transistor test structures to evaluate the potential of forming nanostructured field effect sensors using simple solution processing

EMSL Geochemistry, Biogeochemistry and Subsurface Science-Science Theme Advisory Panel Meeting

This report covers the topics of discussion and the recommendations of the panel members. On December 8 and 9, 2010, the Geochemistry, Biogeochemistry, and Subsurface Science (GBSS) Science Theme Advisory Panel (STAP) convened for a more in-depth exploration of the five Science Theme focus areas developed at a similar meeting held in 2009. The goal for the fiscal year (FY) 2011 meeting was to identify potential topical areas for science campaigns, necessary experimental development needs, and scientific members for potential research teams. After a review of the current science in each of the five focus areas, the 2010 STAP discussions successfully led to the identification of one well focused campaign idea in pore-scale modeling and five longer-term potential research campaign ideas that would likely require additional workshops to identify specific research thrusts. These five campaign areas can be grouped into two categories: (1) the application of advanced high-resolution, high mass accuracy experimental techniques to elucidate the interplay between geochemistry and microbial communities in terrestrial ecosystems and (2) coupled computation/experimental investigations of the electron transfer reactions either between mineral surfaces and outer membranes of microbial cells or between the outer and inner membranes of microbial cells

EMSL and Institute for Integrated Catalysis (IIC) Catalysis Workshop

Within the context of significantly accelerating scientific progress in research areas that address important societal problems, a workshop was held in November 2010 at EMSL to identify specific and topically important areas of research and capability needs in catalysis-related science

Pegylated Inorganic Nanoparticles

Application of inorganic nanoparticles in diagnosis and therapy has become a critical component in the targeted treatment of diseases. The surface modification of inorganic oxides is important for providing diversity in size, shape, solubility, long-term stability, and attachment of selective functional groups. This Minireview describes the role of polyethylene glycol (PEG) in the surface modification of oxides and focuses on their biomedical applications. Such a PEGylation of surfaces provides stealth characteristics to nanomaterials otherwise identified as foreign materials by human body. The role of PEG as structure-directing agent in synthesis of oxides is also presented. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

ChemInform Abstract: PEGylated Inorganic Nanoparticles

Application of inorganic nanoparticles in diagnosis and therapy has become a critical component in the targeted treatment of diseases. The surface modification of inorganic oxides is important for providing diversity in size, shape, solubility, long-term stability, and attachment of selective functional groups. This Minireview describes the role of polyethylene glycol (PEG) in the surface modification of oxides and focuses on their biomedical applications. Such a PEGylation of surfaces provides stealth characteristics to nanomaterials otherwise identified as foreign materials by human body. The role of PEG as structure-directing agent in synthesis of oxides is also presented. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Atomic-level simulations of misfit dislocation at the interface of Fe2O3/Al2O3 system

When α-Fe2O3 thin films are deposited on α-Al2O3(0 0 0 1) substrates using oxygen plasma assisted molecular beam epitaxy, a periodic distribution of basal dislocations occurs due to lattice mismatch along the interfaces. High-resolution transmission electron microscopy shows, when observed from zone axis, that these dislocations lie at the interface about 7.0 nm apart. Molecular-dynamics simulations were performed in order to understand the formation of misfit dislocations and the interface structural features in Fe2O3/Al2O3 system. It is found that the misfit dislocations are mainly formed in Al2O3 substrates with Burger’s vector of 1/3, and terminated at the interfaces, in consistent with experiments observed previously. These dislocations can dissociate into two partial dislocations with Burger’s vectors of 1/3 and 1/3 by forming stacking faults on (0 0 0 1) planes. The core structures of the misfit dislocations in semicoherent interfaces are analyzed in detail, and the misfit dislocations have narrow cores in the plane of the interfaces

Investigation of misfit dislocations at the Fe₂O₃/Al₂2O₃ interface

Recent studies of buried interface α-Fe2O3(0001)/α-Al2O3 using high resolution transmission electron microscopy (HRTEM) and ion scattering techniques reveal the existence of disordering at the interface due to the misfit dislocations. Molecular dynamics (MD) calculations were carried out to understand the formation of misfit dislocations and the interface structural features. The misfit dislocations are formed because of the lattice mismatch between the substrate and the film. Ion scattering simulations were carried out using VEGAS code, in which the atomic positions generated by the MD calculations were used. The hitting probabilities determined from these simulations were compared with the experimental surface and interface peaks obtained from the aligned RBS spectrum

Comparison of analytical techniques for analysis of arsenic adsorbed on carbon

Activated carbon (AC) has been used extensively to treat arsenic-contaminated groundwater for a number of years. To date, attempts to quantify directly the amount of arsenic removed by the activated carbon using nondestructive methods has been limited. High-energy ion beam based proton induced x-ray emission (PIXE) is ideally suited to investigate the issues regarding the quantification of trace metals in solids. In this study, after the adsorption of arsenic on activated carbon, arsenic concentration in granular activated carbon (GAC) and powder activated carbon (PAC) were quantified using Pixe. The PIXE results were compared with atomic absorption spectrometry (AAS) and inductively coupled plasma optical emission spectrometry (ICP-OES) measurements. Some differences are observed between these measurements. The differences are greater in the case of GAC compared to PAC. These differences are mainly due to the inhomogeneous structure of GAC and PAC, which includes the variable surface properties such as surface area and pore sizes in each granule or particle. The larger differences are mainly due to the increased particle dimensions of GAC compared to PAC and the nature of the internal pore structure of GAC, which results in different amounts of arsenic adsorbed on different granules of GAC or even in different regions of one granule. This inhomogeneity of arsenic concentration is clearly visible in the arsenic concentration map generated for a single GAC particle using microbeam PIXE. Copyright © 2006, CAWQ