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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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It was shown that a three-point second difference estimator is nearly optimal for estimating frequency drift in many common atomic oscillators. A formula for the uncertainty of this estimate as a function of the integration time and of the Allan variance associated with this integration time is derived.
When a positive detection of a narcotic occurs during the search of a vessel, a decision has to be made whether further intensive search is warranted. In terms of unwarranted delays of vessels and possible property damage, the accuracy of the analytical determination is very important. Analytical accuracy becomes critical when the data may be used in court actions as evidence. For this purpose, the U.S. Coast Guard has been investigating several confirmatory ion mobility spectrometry (IMS) field methods for the detection and identification of cocaine. This paper presents the findings of our investigations on the use of catalytic pyrolysis and base hydrolysis as confirmatory methods. The catalytic effects of various metals on the pyrolysis reaction are reported. In addition, the effects of several different ion mobility spectrometer sample transfer mediums and varying laboratory conditions on the base hydrolysis of the cocaine molecule are also be reported.
This paper examines the stock market s reaction to JetBlue s Initial Public Offering (1PO) and subsequent price movements of the stock. In particular, w e examine whether the euphoria surrounding JetBlue s IPO carried over to other firms in the sector by testing whether the shares of JetBlue s competitors showed a significant price reaction to JetBlue s IPO. JetBlue's IPO took place just a few months following September 11, 2001. These events resulted in dramatic changes in the airline industry and had significant implications on the economic gains of airlines. We examine JetBlue s accounting and stock performance and compare it to the relative performance of Southwest Airlines (SWA), a representative of the loa-cost carrier group. In addition, we compare both JetBlue's and SWA's financial condition and the relative performance of their stock to two mainline U S. carriers, Continental and Northwest. representatives of the conventional-cost carrier group. We analyze whether there are any performance differences among the low-cost carriers and between low-cost carriers and conventional-cost carriers. In particular, we examine whether low-cost carriers were able to sustain the economic impacts of 9/11 better than the conventional-cost carriers.
An approximating algorithm for computing equvalent degrees of freedom of the Modified Allan Variance and its square root, the Modified Allan Deviation (MVAR and MDEV), and the Time Variance and Time Deviation (TVAR and TDEV) is presented, along with an algorithm for approximating the inverse chi-square distribution.
Purpose of presentation: (1) Status update on the developing methodology to revise sub-system sparing targets. (2) To describe how to incorporate uncertainty into spare assessments and why it is important to do so (3) Demonstrate hardware risk postures through PACT evaluation
This paper is intended to provide a reliable methodology for those tasked with generating price tags on construction (C0F) and research and development (R&D) activities in the NASA performance world. This document consists of a collection of cost-related engineering detail and project fulfillment information from early agency days to the present. Accurate historical detail is the first place to start when determining improved methodologies for future cost and schedule estimating. This paper contains a beneficial proposed cost estimating method for arriving at more reliable numbers for future submits. When comparing current cost and schedule methods with earlier cost and schedule approaches, it became apparent that NASA's organizational performance paradigm has morphed. Mission fulfillment speed has slowed and cost calculating factors have increased in 21st Century space exploration.
In October 2014, the Mars Science Laboratory (MSL) "Curiosity" rover drilled into the sediment at the base of Mount Sharp in a location namsed Cionfidence Hills (CH). CH marked the fifth sample pocessed by the Sample Analysis at Mars (SAM) instrument suite since Curiosity arrived in Gale Crater, with previous analyses performed at Rocknest (RN), John Klein (JK), Cumberland (CB), and Windjana (WJ). Evolved gas analysis (EGA) of all samples has indicated H2O as well as O-, C- and S-bearing phases in the samples, often at abundances that would be below the detection limit of the CheMin instrument. By examining the temperatures at which gases are evolved from samples, SAM EGA data can help provide clues to the mineralogy of volatile-bearing phases when their identities are unclear to CheMin. SAM may also detect gases evolved from amorphous material in solid samples, which is not suitable for analysis by CheMin. Finally, the isotopic composition of these gases may suggest possible formation scenarios and relationships between phases. We will discuss C isotope ratios of CO2 evolved from the CH sample as measured with SAM's quadrupole mass spectrometer (QMS) and draw comparisons to samples previously analyzed by SAM.
No abstract available
Commercial supersonic flight is currently forbidden over land because sonic booms have historically caused unacceptable annoyance levels in overflown communities. NASA is providing data and expertise to noise regulators as they consider relaxing the ban for future quiet supersonic aircraft. One deliverable NASA will provide is a predictive model for indoor annoyance to aid in setting an acceptable quiet sonic boom threshold. A laboratory study was conducted to determine how indoor vibrations caused by sonic booms affect annoyance judgments. The test method required finding the point of subjective equality (PSE) between sonic boom signals that cause vibrations and signals not causing vibrations played at various amplitudes. This presentation focuses on a few statistical techniques for estimating the interval around the PSE. The techniques examined are the Delta Method, Parametric and Nonparametric Bootstrapping, and Bayesian Posterior Estimation.
No abstract available
In order to accomplish dependable onboard evolution, we develop a methodology which is called guarded software upgrading (GSU).
UNKNOWN
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Planetary exploration missions seeking past or present signs of life carry not just a single instrument, but a suite. There is a need to study how these multiple data types can be combined to create “composite” biosignatures [1]. Algorithmic methods using existing data on living and non-living systems, though limited by the n = 1 of Earth, can nonetheless be informative. We assembled a database of 1277 measurements spanning 16 representative systems either indicative or non-indicative of life. Five classification (machine learning) methods were used on each individual data type, then on the entire set. This abstract summarizes the results; the data is described in more detail in [2], and methods in [3].
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