Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “FLASH”

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.

At least 577 records · Page 32
All sourcesNASA NTRSDOE OSTI
NASA NTRS2023

Flash Thermal Diffusivity Measurements and Inspection of Additively Manufactured Ti-6Al-4V Specimens with Varying Process Parameters

Flash thermal diffusivity measurements were obtained on additively manufactured Ti-6Al-4V disk shaped specimens with various process parameters. For additively manufactured metal parts, processing parameters such as laser power and scanning speed are critical to ensure the desired microstructure. For this study, the laser powder bed fusion process parameters were changed at various angular sections on a 21 mm diameter and 3.0 mm thick disk. The measurement of thermal diffusivity was performed by fitting a 1-dimensional thermal model to the data pixel by pixel to produce an inspection image. The image revealed the detection of defects such as lack of fusion porosity and areas of aggregated porosity. The thermal diffusivity imagery was compared to immersion scan ultrasonic and X-ray computed tomography (CT) measurements for validation. Based on these results, additional samples were investigated using a single side thermal inspection technique to detect lack of fusion porosity and near surface voids.

thermal nondestructive evaluation↗
NASA NTRSDate not supplied

Multi-Functional Flash Lidar for Precision Safe Landing in Challenging Terrains

A Flash Lidar utilizing a novel Super-Resolution (SR) technique has been developed for providing Terrain Relative Navigation and Hazard Avoidance capabilities onboard landing vehicles. Processing algorithms for precision navigation and safe landing location identification take advantage of the uniform fixed pixels property of generated high resolution Digital Elevation Maps (DEMs) to achieve high reliability operation in near real-time. This paper describes the current and next generation breadboard units, report the results of recent dynamic tests, and explain the operational concept as envisioned for future landing missions.

3-D Imaging↗
NASA NTRSDate not supplied

Multi-Functional Flash Lidar for Precision Safe Landing in Challenging Terrains

A Flash Lidar utilizing a novel Super-Resolution (SR) technique has been developed for providing Terrain Relative Navigation and Hazard Avoidance capabilities onboard landing vehicles. Processing algorithms for precision navigation and safe landing location identification take advantage of the uniform fixed pixels property of generated high resolution Digital Elevation Maps (DEMs) to achieve high reliability operation in near real-time. This paper describes the current and next generation breadboard units, report the results of recent dynamic tests, and explain the operational concept as envisioned for future landing missions.

3-D Imaging↗
NASA NTRS2024

Global Flash Droughts Characteristics: Onset, Duration and Extent at Watershed Scales

Addressing impacts of flash droughts (FDs) on the water-food nexus requires a understanding of FD mechanisms and drivers at the watershed level. Examining climatic drivers, dry and wet spell lengths from 1980 to 2019, we analyzed FD spatial and temporal characteristics, emphasizing areal extent, onset time, and duration. Our findings reveal substantial variations in FDs among different watersheds. Notably, watersheds in the Southern Hemisphere are witnessing expanding, faster-developing, and longer-lasting FDs, aligning with climate variations in precipitation and temperature. Additionally, at the watershed scale, the onset and duration of FDs are more influenced by the intensity (magnitude and variability) of climatic drivers than the average length of wet and dry periods. FD-extents, however, correlate with both climatic conditions and wet and dry periods, underscoring watershed connectivity. Ultimately, our results underscore the necessity for research to comprehend the interplay between FDs and watershed characteristics and how it manifests in overall water resource management.

Maheshwari Neelam↗
NASA NTRSDate not supplied

Development of Flash Lidar Sensor for Precision Safe Landing

A Flash Lidar utilizing a novel Super-Resolution (SR) technique has been developed for providing Terrain Relative Navigation and Hazard Avoidance capabilities onboard landing vehicles. Processing algorithms for precision navigation and safe landing location identification take advantage of the uniform fixed pixels property of generated high resolution Digital Elevation Maps (DEMs) to achieve high reliability operation in near real-time. This paper describes the current and next generation breadboard units, report the results of recent dynamic tests, and explain the operational concept as envisioned for future landing missions.

3-D Imaging↗
DOE OSTI2020

Flashing ratchets

Provided herein are flashing ratchets that produce transport based on the oscillating application of regularly-spaced, asymmetric potentials. In particular, devices are provided that transport electrons without the requirement of an overall source-drain bias favoring electron transport.

42 ENGINEERING↗
DOE OSTI2022

Flash ironmaking drop tube furnace system

A flash ironmaking drop tube furnace includes a primary reaction section having a refractory, an induction coil around the refractory, insulation located between the refractory and the induction coil, and a susceptor located inside the refractory, the susceptor being formed of a material that is heated by induction when electrical current flows through the induction coil, and having at least one interior channel through which particles can pass. The furnace further includes a muffle, located below the primary reaction section; an outer shell surrounding the muffle; at least one heater located adjacent to the muffle; insulation located between the at least one heater and the outer shell; at least one particle feeder that feeds a predetermined volume of particles into the furnace above the primary reaction section; and an inlet port for injecting gas into the furnace, the inlet port being located so that the gas flows through the susceptor and muffle in parallel with the particles.

Green, Edward↗
DOE OSTI2023

Flash radiotherapy accelerator

Methods, devices and systems for ultra-high dose radiotherapy are disclosed. The described techniques rely in-part on active switching control of a photoconductive switch during the time the accelerator is accelerating charged particles to produce the output radiation at the desired dose rates. One flash radiotherapy system includes an induction accelerator, and a controllable switch coupled to the induction accelerator. The switch is operable to produce a plurality of voltage pulses to drive the induction accelerator. The radiotherapy system also includes a radiation measurement device to measure output radiation produced by the radiotherapy system and provide feedback to the controllable switch. The controllable switch is operable to, based on the received feedback, modify an amplitude, shape, spacing, number or width of the voltage pulses that are supplied to the particle accelerator to deliver the desired output radiation.

Sampayan, Stephen E.↗
NASA NTRS2017

Micron MT29F128G08AJAAA 128GB Asynchronous Flash Memory Total Ionizing Dose Characterization Test Report

The purpose of this test was to characterize the Micron MT29F128G08AJAAAs parameter degradation for total dose response and to evaluate and compare lot date codes for sensitivity. In the test, the device was exposed to both low dose and high dose rate (HDR) irradiations using gamma radiation. Device parameters such as leakage currents, quantity of upset bits and overall chip and die health were investigated to determine which lot is more robust.

Flash Memory↗
NASA NTRS2018

Flash Optical Energy from the Geostationary Lightning Mapper

The Geostationary Operational Environmental Satellite - 16 (GOES-16) Geostationary Lightning Mapper (GLM) is evaluated for many months during the Post Launch Product Test (PLPT) phase in order to ensure that optimal products are available for both the operational forecasting and broader scientific research communities. An essential aspect of the PLPT phase is to obtain a benchmark of the GLM lightning optical amplitude, so that any long-term degradation in the nadir-staring GLM camera system can be realized and quantitatively assessed. This work provides a preliminary benchmark over a 60-day period using Provisionally Validated data.

Flash↗