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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.

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At least 595 records · Page 33
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

EPCAPE-PT-LANL Measurements: Scanning Mobility Particle Sizer

Coastal cities offer a unique environment for studying aerosol-cloud interactions and the effects of urban emissions on cloud properties. As part of the Eastern Pacific Cloud Aerosol Precipitation Experiment (EPCAPE), the Partitioning Thrust by Los Alamos National Laboratory (EPCAPE-PT-LANL) was conducted. Our campaign focused on measuring the optical and chemical properties of aerosols and their interactions within marine stratocumulus clouds in La Jolla, California. EPCAPE-PT-LANL enhances the primary goals of EPCAPE through innovative observations of vapor-phase transitions between aerosols and cloud droplets, the impact of black carbon on aerosol-cloud dynamics, and the effects of cloud processing on aerosol optical properties. Instrument: Scanning Mobility Particle Sizer (TSI), DMA Classifier Model 3082 + CPC Detector Model 3752. Data Notes: The SMPS dataset is limited due to necessary instrument maintenance and subsequent extensive downtime. Data is only available from October 21 to November 8, 2023. Post November 22, 2023, the NanoScan instrument provided coverage for the latter half of the campaign. To ensure consistency, the data was resampled into uniform size bins ranging from 15 nm to 667 nm. This adjustment was required due to changes in size bins and the maximum diameter that occurred after maintenance and repairs. Multiple Charge Correction applied, Nanoparticle Agglomerate Mobility Analysis not applied, and Diffusion Correction applied. Header: - List [15 nm to 667 nm] middle of the size bin in nanometers: Data reports the concentration particles in this size bin per cubic centimeter, dN/dLog(dp). - CVI_Flag[bool]: A boolean flag indicating whether the Counterflow Virtual Impactor (CVI) was active (true) or inactive (false) during the measurement.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2026

X-Band Scanning ARM Precipitation Radar, CF/Radial Formatted, Quality Controlled

The X-band Scanning ARM Precipitation Radar (X-SAPR) is an X-band dual-polarization Doppler weather radar. The X-SAPR operates in a simultaneous transmit and receive (STAR) mode, meaning that the transmit signal is split so that power is transmitted on both horizontal and vertical polarizations at the same time. The X-SAPR transmitter is a 200 kW (peak power) magnetron. The receiver is based upon the Vaisala RVP-900 and runs Vaisala’s IRIS software. In addition to the first three Doppler moments (reflectivity, radial velocity, and spectra width), the X-SAPR also provides differential reflectivity, correlation coefficient, and specific differential phases. The dual-polarization variables enable estimates of rainfall rates and identification of precipitation types. At the Southern Great Plains site, three X-SAPRs surround the Central Facility, allowing the use of multi-Doppler velocity retrievals to estimate wind fields.

xsaprcfrqc↗
DOE OSTI2024

PSU-BSEC Doppler Lidar Processed Scans

This data repository includes the processed vertically staring measurements (stare files) made by the Pennsylvania State University (PSU) Doppler Lidar as a part of the Baltimore Social-Environmental Collaborative Urban Integrated Field Laboratory (BSEC UIFL). The PSU Doppler Lidar measures aerosol backscatter intensity (m-1 sr-1), signal-to-noise ratio, and radial velocity (i.e., vertical velocity in the case of stare files, units: m/s) at approximately 1 Hz temporal resolution and 30 m spatial resolution. Future updates will include angled scans, sky cam images, example figures, and the original .hpl files. For further information, please email Nicholas Prince, nec5299@psu.edu.

Air Quality↗
DOE OSTI2024

PSU-BSEC Doppler Lidar Processed Scans

This data repository includes the processed vertically staring measurements (stare files) and the angled scans (profile files) necessary to calculate horizontal winds retrieved by the Pennsylvania State University (PSU) Doppler Lidar as a part of the Baltimore Social-Environmental Collaborative Urban Integrated Field Laboratory (BSEC UIFL). The PSU Doppler Lidar measures aerosol backscatter intensity (m-1 sr-1), signal-to-noise ratio, and radial velocity (i.e., vertical velocity in the case of stare files, units: m/s) at approximately 1 Hz temporal resolution and 30 m spatial resolution. Within the "stare_data" subdirectory there exist example figures of all retrieved data. For further information, please email Nicholas Prince, nec5299@psu.edu.

Air Quality↗
DOE OSTI2020

Ultra-wideband mutual coupling compensation of active electronically scanned arrays in multi-channel radar systems

Technologies pertaining to the calibration of ultra-wide-band active-electronically-scanned arrays to compensate for transmit and receive mutual coupling between array elements and/or non-ideal isolated channels are described herein. A plurality of near-field measurements are taken by way of probe or probes that may be moved among a plurality of positions aligned with respective elements in the array. For each position of the probe, each of the elements of the array is stimulated to transmit or receive a calibration signal to or from the probe, respectively. Frequency-domain transfer functions are computed from the received signals by the probe or the element for each of the array elements in each of the positions of the probe. The inverse of the matrix of transfer functions comprise frequency-domain transmit and receive correction factors that are used to modify desired array inputs/outputs such that the modified signals correct for mutual coupling between elements in the array.

42 ENGINEERING↗
DOE OSTI2020

A three-dimensional reconstruction algorithm for scanning transmission electron microscopy data from thick samples

Increasing interest in three-dimensional nanostructures adds impetus to electron microscopy techniques capable of imaging at or below the nanoscale in three dimensions. We present a reconstruction algorithm that takes as input a focal series of four-dimensional scanning transmission electron microscopy (4D-STEM) data and transcends the prevalent structure retrieval algorithm assumption of a very thin specimen homogenous along the optic axis. We demonstrate this approach by reconstructing the different layers of a lead iridate (Pb$_2$Ir$_2$O$_7$) and yttrium-stabilized zirconia (Y$_{0.095}$Zr$_{0.905}$O$_2$) heterostructure from data acquired with the specimen in a single plan-view orientation, with the epitaxial layers stacked along the beam direction.

Brown, Hamish G↗
DOE OSTI2021

Methods and devices configured to operated scanning tunneling microscopes using out-of-bandwidth frequency components added to bias voltage and related software

In the system and method disclosed, an ultrahigh vacuum (UHV) scanning tunneling microscope (STM) tip is used to selectively desorb hydrogen atoms from the Si(100)-2X1:H surface by injecting electrons at a negative sample bias voltage. A new lithography method is disclosed that allows the STM to operate under imaging conditions and simultaneously desorb H atoms as required. A high frequency signal is added to the negative sample bias voltage to deliver the required energy for hydrogen removal. The resulted current at this frequency and its harmonics are filtered to minimize their effect on the operation of the STM's feedback loop. This approach offers a significant potential for controlled and precise removal of hydrogen atoms from a hydrogen-terminated silicon surface and thus may be used for the fabrication of practical silicon-based atomic-scale devices.

Moheimani, Seyed Omid Reza↗
DOE OSTI2023

Fast image acquisition system and method using pulsed light illumination and sample scanning to capture optical micrographs with sub-micron features

An optical inspection system for detecting sub-micron features on a sample component. The system may have a controller, a camera responsive to the controller for capturing images, an objective lens able to capture submicron scale features on the sample component, and a pulsed light source. The pulsed light source may be used to generate light pulses. The camera may be controlled to acquire images, using the objective lens, only while the pulsed light source is providing light pulses illuminating a portion of the sample component. Relative movement between the sample component and the objective lens is provided to enable at least one of a desired subportion or an entirety of the sample component to be scanned with the camera.

Yoo, Jae Hyuck↗