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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 1,171 records · Page 65
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Using Distributed Fiber-Optic Strain Sensing to Estimate Modal Generalized Modal Coordinates from Flight-Test Data

Background and Motivation - Problem - Contemporary aircraft carry around structural mass so that the flutter instabilities lie well outside of the operational envelope. - Better methods of measuring the structural state could allow reduction of the extra structural weight. - Modal filtering - Standard method in structural analysis - Deformations are a combination of mode shapes - Modal filtering is estimating these modal coordinates from data - Often ordinary least squares methods - Often applied to simpler test articles - Factor Analysis - Classic (in psychology) analysis method - Measurements are a combination of small number of unmeasurable variables - Lessons from this factor can be adapted to improve the modal filtering methods

Jeffrey Ouellette↗
NASA NTRSDate not supplied

Using Distributed Fiber-optic Strain Sensing to Estimate Generalized Modal Coordinates from Flight-test Data

Background and Motivation - Problem - Contemporary aircraft carry around structural mass so that the flutter instabilities lie well outside of the operational envelope. - Better methods of measuring the structural state could allow reduction of the extra structural weight - Modal filtering - Standard method in structural analysis - Deformations are a combination of mode shapes - Modal filtering is estimating these modal coordinates from data - Often ordinary least squares methods - Often applied to simpler test articles - Factor Analysis - Analysis method from psychology - Measurements are a combination of small number of unmeasurable variables. - Lessons from factor analysis can be adapted to improve the modal filtering methods

Jeffrey Ouellette↗
NASA NTRSDate not supplied

Multi-Gbps Fiber-Optic Wavefront Sensing Coherent Optical Receiver

We report recent progress on technology developments at the NASA Glenn Research Center using photonic lanterns for coherent optical communications applications. In particular, the development of a spatial mode-diversity optical receiver using a photonic lantern combined with a photonic integrated circuit (PIC). The PIC is designed for compatibility with the NASA Laser Communication Relay Demonstration’s (LCRD) differential phase-shift keying signaling format. We report on the PIC design and future characterization and packaging efforts. Additionally, we report on the development of a 19-channel photonic lantern and provide updates on efforts to use the photonic lantern as a wavefront sensing device. The photonic lantern insertion loss, and spatial-mode transfer characteristics are detailed, as well as the development of a predictive framework in which the intensities in the 19 single-mode output channels are used to reconstruct the wavefront of the light entering the multi-moded input side of the lantern. Finally, we discuss concepts for potential future systems using photonic lanterns and PICs that combine both wavefront sensing and coherent communications onto a single integrated platform.

Optical Communications↗
DOE OSTI2019

Secure fiber optic seals enabled by quantum optical communication concepts

Described herein are various technologies pertaining to detecting tampering of a seal based upon quantum optical communication via a communications channel comprising the seal. A plurality of pulses of light encoded with random data are transmitted on the communications channel, whereupon they are received and their data values measured. The measured data values of the pulses are then compared to the known transmitted data to determine a correlation statistic between the transmitted and received data values. Tampering with the seal can be detected based upon identifying that the correlation statistic has dropped below a threshold non-tampered level of correlation between transmitted and received values.

Sarovar, Mohan↗
DOE OSTI2020

Optical fiber receptacle cover

A cover for partially covering and protecting cables plugged into a receptacle is provided. The receptacle includes a face plate with a first hole through which a first fastener secures the face plate to a face of the receptacle. The cover comprises a plurality of walls at least partially defining a hollow chamber, a slot adjacent to the chamber and configured to receive the face plate when the cover is slid over the face plate, an opening that leads to the chamber and the slot, and a first channel extending partially through the chamber and configured to provide access to the fastener.

42 ENGINEERING↗