Tribochemical polymerization of the adsorbed n-pentanol on SiO2 during rubbing: When does it occur and is it responsible for effective vapor phase lubrication?
Langmuir
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Langmuir
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Sandia National Laboratories (SNL) and the Nuclear Security Science and Policy Institute (NSSPI) at Texas A&M University are working with Middle East regional partners to set up a nuclear energy safety, safeguards, and security educational institute in the Gulf region. SNL and NSSPI, partnered with the Khalifa University of Science, Technology, and Research (KUSTAR), with suppot from its key nuclear stakeholders, the Emirates Nuclear Energy Corporation (ENEC), and the Federal Authority for Nuclear Regulation (FANR), plan to jointly establish the institute in Abu Dhabi. The Gulf Nuclear Energy Infrastructure Institute (GNEII) will be a KUSTAR-associated, credit-granting regional education program providing both classroom instruction and hands-on experience. The ultimate objective is for GNEII to be autonomous - regionally funded and staffed with personnel capable of teaching all GNEII courses five years after its inauguration. This is a strategic effort to indigenize a responsible nuclear energy culture - a culture shaped by an integrated understanding of nuclear safety, safeguards and security - in regional nuclear energy programs. GNEII also promotes international interests in developing a nuclear energy security and safety culture, increases collaboration between the nuclear energy security and safety communities, and helps to enhance global standards for nuclear energy technology in the Middle East.
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Sandia National Laboratories (SNL) and the Nuclear Security Science and Policy Institute (NSSPI) at Texas A&M University are working with Middle East regional partners to set up a nuclear energy safety, safeguards, and security educational institute in the Gulf region. SNL and NSSPI, partnered with the Khalifa University of Science, Technology, and Research (KUSTAR), with suppot from its key nuclear stakeholders, the Emirates Nuclear Energy Corporation (ENEC), and the Federal Authority for Nuclear Regulation (FANR), plan to jointly establish the institute in Abu Dhabi. The Gulf Nuclear Energy Infrastructure Institute (GNEII) will be a KUSTAR-associated, credit-granting regional education program providing both classroom instruction and hands-on experience. The ultimate objective is for GNEII to be autonomous - regionally funded and staffed with personnel capable of teaching all GNEII courses five years after its inauguration. This is a strategic effort to indigenize a responsible nuclear energy culture - a culture shaped by an integrated understanding of nuclear safety, safeguards and security - in regional nuclear energy programs. GNEII also promotes international interests in developing a nuclear energy security and safety culture, increases collaboration between the nuclear energy security and safety communities, and helps to enhance global standards for nuclear energy technology in the Middle East.
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Solar Energy Materials and Solar Cells
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Sandia National Laboratories, Albuquerque, N.M., USA, in collaboration with the High Current Electronic Institute (HCEI), Tomsk, Russia, is developing a new paradigm in pulsed power technology: the Linear Transformer Driver (LTD) technology. This technological approach can provide very compact devices that can deliver very fast high current and high voltage pulses straight out of the cavity with out any complicated pulse forming and pulse compression network. Through multistage inductively insulated voltage adders, the output pulse, increased in voltage amplitude, can be applied directly to the load. The load may be a vacuum electron diode, a z-pinch wire array, a gas puff, a liner, an isentropic compression load (ICE) to study material behavior under very high magnetic fields, or a fusion energy (IFE) target. This is because the output pulse rise time and width can be easily tailored to the specific application needs. In this paper we briefly summarize the developmental work done in Sandia and HCEI during the last few years, and describe our new MYKONOS Sandia High Current LTD Laboratory.
Overall project goal: Obtain the fundamental surface chemistry knowledge needed for the design and optimal utilization of NOx trap catalysts, thereby helping to speed the widespread adoption of this technology. Relevance to VT Program goals: Effective, durable advanced aftertreatment systems for lean-burn engines must be available if the fuel economy advantages of these engines are to be realized. Specific current year objective: Identify and correct any deficiencies in the previously developed reaction mechanism describing normal storage/regeneration cycles, and complete development of a supplementary mechanism accounting for the effects of sulfation. A fundamental understanding of LNT chemistry is needed to realize the full potential of this aftertreatment technology, which could lead to greater use of fuel-efficient lean-burn engines. We have used a multi-tiered approach to developing an elementary chemical mechanism benchmarked against experimental data: (1) Simulate a set of steady flow experiments, with storage effects minimized, to infer a tentative mechanism for chemistry on precious metal sites (completed). (2) Simulate a set of long cycle experiments to infer a mechanism for NOx and oxygen storage sites while simultaneously finalizing precious metal chemistry (completed). (3) Simulate a simplified sulfation/desulfation protocol to obtain a supplementary set of reactions involving sulfur on all three kinds of sites (nearly completed). (4) Investigate the potential role of reductants other than CO and H{sub 2}. While simulation of isothermal experiments is the preferred way to extract kinetic parameters, simulation of realistic storage/regeneration cycles requires that exotherms be considered. Our ultimate goal is to facilitate improved designs for LNT-based aftertreatment systems and to assist in the development of improved catalysts.
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Theory and experiment suggest nanoscale hydride particles are destabilized relative to bulk, but the origin of this effect is unclear. Both size and local environment may play a role. The overall project objective is to achieve tunable thermodynamics for hydrogen storage materials by controlling nanoparticle size, composition, and environment. Key Goals for FY09 are: (1) Demonstrate and downselect infiltration methods; (2) Measure desorption kinetics for MgH{sub 2} and NaAlH{sub 4} nanoparticles and LiBH{sub 4} thin films; (3) Benchmark DFT and atomistic nanoparticle models using Quantum Monte Carlo (QMC); and (4) Quantify effect of nanoparticle size on {Delta}H{sub d}{sup o} using MgH{sub 2} as initial example. Summary of the key results are: (1) New highly ordered nanoporous templates enable systematic probing of nanoscale effects - Nanoscale NaAlH{sub 4} particles (as small as 1.5 nm diameter) exhibit improved H{sub 2} desorption kinetics relative to bulk and Preliminary data suggest MgH{sub 2} nanoparticle formation and possibly improved desorption kinetics; (2) Benchmarking DFT against QMC reveals significant errors that are non-systematic (H{sub 2} desorption energies underpredicted by as much as 30 kJ/mol); (3) QMC predicts greatest effect of size is for extremely small particles; e.g. (MgH{sub 2}){sub n}, n {le} 6 which is much smaller than predicted by Wolfe construction approach and observed in experiments and it suggests factors other than electronic structure (e.g. surrounding chemical environment) influence stability; (4) New NanoPEGS code developed and tested for MgH{sub 2} 2particles; and (5) New mass spec tool (STMBMS) reveals key details of hydrogen desorption process.
Objectives are to enable development and implementation of codes and standards for H{sub 2} containment components: (1) Evaluate data on mechanical properties of materials in H{sub 2} gas - Technical Reference on Hydrogen Compatibility of Materials; (2) Generate new benchmark data on high-priority materials - Pressure vessel steels, stainless steels; and (3) Establish procedures for reliable materials testing - Sustained-load cracking, fatigue crack propagation. Summary of this presentation are: (1) Completed measurement of cracking thresholds (K{sub TH}) for Ni-Cr-Mo pressure vessel steels in high-pressure H{sub 2} gas - K{sub TH} measurements required in ASME Article KD-10 (2) Crack arrest test methods appear to yield non-conservative results compared to crack initiation test methods - (a) Proposal to insert crack initiation test methods in Article KD-10 will be presented to ASME Project Team on Hydrogen Tanks, and (b) Crack initiation methods require test apparatus designed for dynamic loading of specimens in H{sub 2} gas; and (3) Demonstrated ability to measure fatigue crack growth of pressure vessel steels in high-pressure H{sub 2} gas - (a) Fatigue crack growth data in H{sub 2} required in ASME Article KD-10, and (b) Test apparatus is one of few in U.S. or abroad for measuring fatigue crack growth in >100 MPa H{sub 2} gas.
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