SEARCH · Engineering Papers
Results for “controller”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
An allosteric model for control of pore opening by substrate binding in the EutL microcompartment shell protein
Abstract not provided
Ultrafast study of phonon transport in isotopically controlled semiconductor nanostructures: Phonons in isotopically controlled multilayers
Isotopically modulated silicon and germanium multilayers are analyzed by means of femtosecond spectroscopy and pulsed X-ray scattering for determining thermal conductivity and phonon modes. Isotopic modulation decreases thermal conductivity stronger than expected from a band bending model in the coherent phonon transport regime, in particular for silicon. Femtosecond spectroscopy and X-ray scattering resolve zone-folded vibration modes, which are located at the edge of the new, smaller Brillouin zone due to the multilayer periodicity. These modes can contribute to the reduction of thermal conductivity by Umklapp processes within the zone-folded mini-bands. Color-coded increase in ultrafast X-ray scattering in vicinity to the mini-zone boundary of a germanium multilayer.
A Modal Craig-Bampton Substructure for Experiments Analysis Control and Specifications.
Abstract not provided.
Environmental Controls on the Activity of Aquifer Microbial Communities in the 300 Area of the Hanford Site
Aquifer microbes in the 300 Area of the Hanford Site in southeastern Washington State, USA are periodically exposed to U(VI) concentrations that can range up to 10 μM in small sediment fractures. Assays of 35 H-leucine incorporation indicated that both sediment-associated and planktonic microbes were metabolically active, and that organic C was growth-limiting in the sediments. Although bacteria suspended in native groundwater retained high activity when exposed to 100 μM U(VI), they were inhibited by U(VI) < 1 μM in synthetic groundwater that lacked added bicarbonate. Chemical speciation modeling suggested that positively-charged species and particularly (UO2)3(OH)5+ rose in concentration as more U(VI) was added to synthetic groundwater, but that carbonate complexes dominated U(VI) speciation in natural groundwater. U toxicity was relieved when increasing amounts of bicarbonate were added to synthetic groundwater containing 4.5 μM U(VI). Pertechnetate, an oxyanion that is another contaminant of concern at the Hanford Site, was not toxic to groundwater microbes at concentrations up to 125 μM.
Planetary and synoptic-scale dynamic control of extreme cold wave patterns over the United States
Not Available
Metrics for understanding large-scale controls of multivariate temperature and precipitation variability
Not Available
Valuing the Ozone-Related Health Benefits of Methane Emission Controls
Methane is a greenhouse gas that oxidizes to form ground-level ozone, itself a greenhouse gas and a health-harmful air pollutant. Reducing methane emissions will both slow anthropogenic climate change and reduce ozone-related mortality. We estimate the benefits of reducing methane emissions anywhere in the world for ozone-related premature mortality globally and for eight geographic regions. Our methods are consistent with those used by the U.S. Government to estimate the Social Cost of Carbon (SCC). We find that the global short- and long-term premature mortality benefits due to reduced ozone production from methane mitigation are (2011)$790 and $1775 per tonne methane, respectively. These correspond to approximately 70% and 150% of the valuation of methane’s global climate impacts using the SCC after extrapolating from carbon dioxide to methane using Global Warming Potential (GWP) estimates. Results are most sensitive to the choice of VSL and increase for emission years further in the future. Regionally, most of the global mortality benefits accrue in Asia, but 10% accrue in the United States. This methodology can be used to assess the benefits of methane emission reductions anywhere in the world, including those achieved by national and multinational policies.
Controlled Generation of TiO x –Au Interface Using Titanium Molecular Complex Bearing Pyridyl Anchors: Synthesis, Characterization and Catalysis
Interfacial perimeter sites between metal and support are often important for catalysis. A mononuclear titanium siloxy complex III, Ti(acac) 2 [OSiC 6 H 5 N(OCH 3 ) 2 ] 2 was synthesized to generate TiOx units of different degrees of clustering to decorate Au nanoparticles. Two different methods of preparation were examined; one was to deposit III onto Au/SiO 2 and the other was to form III-covered Au nanoparticle first before deposition onto SiO 2 . The former method generated more highly dispersed TiO x units, while larger domains of TiO 2 were formed with the latter method, as deduced by UV–vis and XAS characterization. A model was proposed to explain how TiO x dispersity could be related to the preparative procedures. These samples were further tested as catalysts in selective oxidation of propane in a stream of O 2 and H 2 . They exhibited different product selectivities. The sample with more dispersed TiO x units were more selective for acetone formation versus propene formation. The results confirmed the important role of both the Au–TiO x interface at the perimeter and the extent of Ti isolation in the TiO x phase in the reaction.
Design and Evaluation of SunSpec-Compliant Smart Grid Controller with an Automated Hardware-in-the-Loop Testbed.
Abstract not provided.
A General Framework for Sensitivity-Based Optimal Control and State Estimation.
Abstract not provided.
Optimal estimation and scheduling in aquifer management using the rapid feedback control method
Not Available
Environmental and biological controls on seasonal patterns of isoprene above a rain forest in central Amazonia
Not Available