The outline of this report is: (1) structures of hexagonal Er meal, ErH{sub 2} fluorite, and molybdenum; (2) texture issues and processing effects; (3) idea of pole figure integration; and (4) promising neutron diffraction work. Summary of this report are: (1) ErD{sub 2} and ErT{sub 2} film microstructures are strongly effected by processing conditions; (2) both x-ray and neutron diffraction are being pursued to help diagnose structure/property issues regarding ErT{sub 2} films and these correlations to He retention/release; (3) texture issues are great challenges for determination of site occupancy; and (4) work on pole-figure-integration looks to have promise addressing texture issues in ErD{sub 2} and ErT{sub 2} films.
Hydrogen energy may provide the means to an environmentally friendly future. One of the problems related to its application for transportation is 'on-board' storage. Hydrogen storage in solids has long been recognized as one of the most practical approaches for this purpose. The H-capacity in interstitial hydrides of most metals and alloys is limited to below 2.5% by weight and this is unsatisfactory for on-board transportation applications. Magnesium hydride is an exception with hydrogen capacity of -8.2 wt.%, however, its operating temperature, above 350 C, is too high for practical use. Sodium alanate (NaAlH{sub 4}) absorbs hydrogen up to 5.6 wt.% theoretically; however, its reaction kinetics and partial reversibility do not completely meet the new target for transportation application. Recently Chen et al. [1] reported that (Li{sub 3}N+2H{sub 2} {leftrightarrow} LiNH{sub 2} + 2LiH) provides a storage material with a possible high capacity, up to 11.5 wt.%, although this material is still too stable to meet the operating pressure/temperature requirement. Here we report a new approach to destabilize lithium imide system by partial substitution of lithium by magnesium in the (LiNH{sub 2} + LiH {leftrightarrow} Li{sub 2}NH + H{sub 2}) system with a minimal capacity loss. This Mg-substituted material can reversibly absorb 5.2 wt.% hydrogen at pressure of 30 bar at 200 C. This is a very promising material for on-board hydrogen storage applications. It is interesting to observe that the starting material (2LiNH{sub 2} + MgH{sub 2}) converts to (Mg(NH{sub 2}){sub 2} + 2LiH) after a desorption/re-absorption cycle.
Biosecurity must be implemented without impeding biomedical and bioscience research. Existing security literature and regulatory requirements do not present a comprehensive approach or clear model for biosecurity, nor do they wholly recognize the operational issues within laboratory environments. To help address these issues, the concept of Biosecurity Levels should be developed. Biosecurity Levels would have increasing levels of security protections depending on the attractiveness of the pathogens to adversaries. Pathogens and toxins would be placed in a Biosecurity Level based on their security risk. Specifically, the security risk would be a function of an agent's weaponization potential and consequences of use. To demonstrate the concept, examples of security risk assessments for several human, animal, and plant pathogens will be presented. Higher security than that currently mandated by federal regulations would be applied for those very few agents that represent true weapons threats and lower levels for the remainder.
This paper describes the analyses and the experimental mechanics program to support the National Aeronautics and Space Administration (NASA) investigation of the Shuttle Columbia accident. A synergism of the analysis and experimental effort is required to insure that the final analysis is valid - the experimental program provides both the material behavior and a basis for validation, while the analysis is required to insure the experimental effort provides behavior in the correct loading regime. Preliminary scoping calculations of foam impact onto the Shuttle Columbia's wing leading edge determined if enough energy was available to damage the leading edge panel. These analyses also determined the strain-rate regimes for various materials to provide the material test conditions. Experimental testing of the reinforced carbon-carbon wing panels then proceeded to provide the material behavior in a variety of configurations and strain-rates for flown or conditioned samples of the material. After determination of the important failure mechanisms of the material, validation experiments were designed to provide a basis of comparison for the analytical effort. Using this basis, the final analyses were used for test configuration, instrumentation location, and calibration definition in support of full-scale testing of the panels in June 2003. These tests subsequently confirmed the accident cause.
Photocatalytic porphyrins are used to reduce metal complexes from aqueous solution and, further, to control the deposition of metals onto porphyrin nanotubes and surfactant assembly templates to produce metal composite nanostructures and nanodevices. For example, surfactant templates lead to spherical platinum dendrites and foam-like nanomaterials composed of dendritic platinum nanosheets. Porphyrin nanotubes are reported for the first time, and photocatalytic porphyrin nanotubes are shown to reduce metal complexes and deposit the metal selectively onto the inner or outer surface of the tubes, leading to nanotube-metal composite structures that are capable of hydrogen evolution and other nanodevices.
This report describes the purpose and results of the two-year, Sandia-sponsored Laboratory Directed Research and Development (LDRD) project entitled Understanding Communication in Counterterrorism Crisis Management The purpose of this project was to facilitate the capture of key communications among team members in simulated training exercises, and to learn how to improve communication in that domain. The first section of this document details the scenario development aspects of the simulation. The second section covers the new communication technologies that were developed and incorporated into the Weapons of Mass Destruction Decision Analysis Center (WMD-DAC) suite of decision support tools. The third section provides an overview of the features of the simulation and highlights its communication aspects. The fourth section describes the Team Communication Study processes and methodologies. The fifth section discusses future directions and areas in which to apply the new technologies and study results obtained as a result of this LDRD.