SEARCH · Engineering Papers
Results for “MIGRATION”
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.
Catalysis-dependent selenium incorporation and migration in the nitrogenase active site iron-molybdenum cofactor
Dinitrogen reduction in the biological nitrogen cycle is catalyzed by nitrogenase, a two-component metalloenzyme. Understanding of the transformation of the inert resting state of the active site FeMo-cofactor into an activated state capable of reducing dinitrogen remains elusive. Here we report the catalysis dependent, site-selective incorporation of selenium into the FeMo-cofactor from selenocyanate as a newly identified substrate and inhibitor. The 1.60 Å resolution structure reveals selenium occupying the S2B site of FeMo-cofactor in the Azotobacter vinelandii MoFe-protein, a position that was recently identified as the CO-binding site. The Se2B-labeled enzyme retains substrate reduction activity and marks the starting point for a crystallographic pulse-chase experiment of the active site during turnover. Through a series of crystal structures obtained at resolutions of 1.32–1.66 Å, including the CO-inhibited form of Av1-Se2B, the exchangeability of all three belt-sulfur sites is demonstrated, providing direct insights into unforeseen rearrangements of the metal center during catalysis.
Replication Data for: Facilitating hydrogen atom migration via a dense phase on palladium islands to a surrounding silver surface
The data underlying this published work have been made publicly available in this repository as part of the IMASC Data Management Plan. This work was supported as part of the Integrated Mesoscale Architectures for Sustainable Catalysis (IMASC), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award # DE-SC0012573.
Replication Data for: Facilitating hydrogen atom migration via a dense phase on palladium islands to a surrounding silver surface
The data underlying this published work have been made publicly available in this repository as part of the IMASC Data Management Plan. This work was supported as part of the Integrated Mesoscale Architectures for Sustainable Catalysis (IMASC), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award # DE-SC0012573.
Replication Data for: Hydrogen migration at restructuring palladium-silver oxide boundaries dramatically enhances reduction rate of silver oxide
The data underlying this published work have been made publicly available in this repository as part of the IMASC Data Management Plan. This work was supported as part of the Integrated Mesoscale Architectures for Sustainable Catalysis (IMASC), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award # DE-SC0012573.
Migration of planets into and out of mean motion resonances in protoplanetary discs: analytical theory of second-order resonances
Explore the source record for details and available documents.
Shifts in avian migration phenologies do not compensate for changes to conditions en route in spring and fall
Explore the source record for details and available documents.
Seasonality of the Migrating Semidiurnal Tide in the Tropical Upper Mesosphere and Lower Thermosphere and its Thermodynamic and Momentum Budget
Explore the source record for details and available documents.
Modeling enstatite chondrites: Reduced rocks with a pinch of oxidized material (affected by varying H 2 O (g)) derived from planetesimals shocked during the epoch of giant–planet migration
Explore the source record for details and available documents.
Semidiurnal Non‐Migrating Tides in the Middle Thermosphere From Far Ultraviolet Observations
Explore the source record for details and available documents.
Apparent migration of the earth in the lunar sky <vidimyye peremeshcheniya zemli na nebe luny<
Ecliptic and horizontal coordinates of earth motion in lunar sky
Injection and migration of charges in the oxide of a metal-oxide-semiconductor structure
Injection of charges in oxide of metal oxide semiconductor structure
Intra-atmospheric migration and dissipation of H and He under the action of magnetohydrodynamic waves
Escape of light hydrogen and helium atoms from earth atmosphere under action of magnetohydrodynamic oscillations
Tracking radar studies of bird migration
The application of tracking radar for determining the flight paths of migratory birds is discussed. The effects produced by various meteorological parameters are described. Samples of radar scope presentations obtained during tracking studies are presented. The characteristics of the radars and their limitations are examined.
The influence of magnetic total intensity and inclination on directions preferred by migrating European robins (Erithacus rubecula)
The directional orientation of migratory European robins in relation to magnetic cues is analyzed. Major efforts were made to determine what information the birds derive from the fields. It was determined that magnetic fields provide: (1) field intensity which determines whether the magnetic field can be used for orientation, (2) a means by which axial direction may be perceived, and (3) a means by which the bird can find the north direction. The north direction is sensed from the angle between gravity and the magnetic field.
Telemetry link for an automatic salmon migration monitor
The antenna and transmitter described in this report were designed for integration into the remote acoustic assessment system for detection of sockeye salmon in the Bristol Bay region of the Bering Sea. The assessment system configuration consists of an upward directed sonar buoy anchored 150 ft below the surface and attached by cable to a spar buoy tethered some 300 ft laterally. The spar buoy contains a telemetry transmitter, power supply, data processing electronics, an antenna and a beacon light.
Techniques development for whale migration tracking
Effort leading to the completion of development and fabrication of expansible whale harnesses and whale-carried instrument pods is described, along with details of the gear. Early preparative effort for a January-February 1974 field expedition is reported.