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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 487 records · Page 27
All sourcesNASA NTRSDOE OSTI
NASA NTRS2013

A Statistical Theory of Bidirectionality

Original concepts related to the quantification and assessment of bidirectionality in strain-gage balances were introduced by Ulbrich in 2012. These concepts are extended here in three ways: 1) the metric originally proposed by Ulbrich is normalized, 2) a categorical variable is introduced in the regression analysis to account for load polarity, and 3) the uncertainty in both normalized and non-normalized bidirectionality metrics is quantified. These extensions are applied to four representative balances to assess the bidirectionality characteristics of each. The paper is tutorial in nature, featuring reviews of certain elements of regression and formal inference. Principal findings are that bidirectionality appears to be a common characteristic of most balance outputs and that unless it is taken into account, it is likely to consume the entire error budget of a typical balance calibration experiment. Data volume and correlation among calibration loads are shown to have a significant impact on the precision with which bidirectionality metrics can be assessed.

DeLoach, Richard↗
NASA NTRS2017

The MSFC Solar Activity Future Estimation (MSAFE) Model

The MSAFE model provides forecasts for the solar indices SSN, F10.7, and Ap. These solar indices are used as inputs to many space environment models used in orbital spacecraft operations and space mission analysis. Forecasts from the MSAFE model are provided on the MSFC Natural Environments Branch's solar webpage and are updated as new monthly observations come available. The MSAFE prediction routine employs a statistical technique that calculates deviations of past solar cycles from the mean cycle and performs a regression analysis to predict the deviation from the mean cycle of the solar index at the next future time interval. The prediction algorithm is applied recursively to produce monthly smoothed solar index values for the remaining of the cycle. The forecasts are initiated for a given cycle after about 8 to 12 months of observations are collected. A forecast made at the beginning of cycle 24 using the MSAFE program captured the cycle fairly well with some difficulty in discerning the double peak that occurred at solar cycle maximum.

Suggs, Ronnie J.↗
NASA NTRS2017

The MSFC Solar Activity Future Estimation (MSAFE) Model

The MSAFE model provides forecasts for the solar indices SSN, F10.7, and Ap. These solar indices are used as inputs to space environment models used in orbital spacecraft operations and space mission analysis. Forecasts from the MSAFE model are provided on the MSFC Natural Environments Branch's solar web page and are updated as new monthly observations become available. The MSAFE prediction routine employs a statistical technique that calculates deviations of past solar cycles from the mean cycle and performs a regression analysis to calculate the deviation from the mean cycle of the solar index at the next future time interval. The forecasts are initiated for a given cycle after about 8 to 9 monthly observations from the start of the cycle are collected. A forecast made at the beginning of cycle 24 using the MSAFE program captured the cycle fairly well with some difficulty in discerning the double peak that occurred at solar cycle maximum.

Suggs, Ron↗
DOE OSTI2018

Laser Induced Breakdown Spectroscopy analysis of europium and samarium in aluminum oxide

The use of Laser Induced Breakdown Spectroscopy as a technique for analysis of europium and samarium concentrations in ceramic aluminum oxide samples was investigated for application to studying lanthanide separation processes. Metal oxide powders of europium and/or samarium were mixed with aluminum oxide at varying concentrations and pressed into pellets. A comparison of different approaches to building a univariate simple linear regression analysis curve is presented. A linear behavior was seen over the total lanthanide concentration range from 0.086 to 12.358 weight percent (wt%). In conclusion, the calculated limits of detection for the univariate calibration curves were determined to range from 0.001 to 0.108 wt% and 0.001 and 0.183 wt% for europium and samarium, respectively.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

RECK is not an independent prognostic marker for breast cancer

Background The REversion-inducing Cysteine-rich protein with Kazal motif (RECK) is a well-known inhibitor of matrix metalloproteinases (MMPs) and cellular invasion. Although high expression levels of RECK have already been correlated with a better clinical outcome for several tumor types, its main function, as well as its potential prognostic value for breast cancer patients, remain unclear. Methods The RECK expression profile was investigated in a panel of human breast cell lines with distinct aggressiveness potential. RECK functional analysis was undertaken using RNA interference methodology. RECK protein levels were also analyzed in 1040 cases of breast cancer using immunohistochemistry and tissue microarrays (TMAs). The association between RECK expression and different clinico-pathological parameters, as well as the overall (OS) and disease-free (DFS) survival rates, were evaluated. Results Higher RECK protein expression levels were detected in more aggressive breast cancer cell lines (T4-2, MDA-MB-231 and Hs578T) than in non-invasive (MCF-7 and T47D) and non-tumorigenic (S1) cell lines. Indeed, silencing RECK in MDA-MB-231 cells resulted in elevated levels of pro-MMP-9 and increased invasion compared with scrambled (control) cells, without any effect on cell proliferation. Surprisingly, by RECK immunoreactivity analysis on TMAs, we found no association between RECK positivity and survival (OS and DFS) in breast cancer patients. Even considering the different tumor subtypes (luminal A, luminal B, Her2 type and basal-like) or lymph node status, RECK remained ineffective for predicting the disease outcome. Moreover, by multivariate Cox regression analysis, we found that RECK has no prognostic impact for OS and DFS, relative to standard clinical variables. Conclusions Although it continues to serve as an invasion and MMP inhibitor in breast cancer, RECK expression analysis is not useful for prognosis of these patients.

60 APPLIED LIFE SCIENCES↗
NASA NTRS1980

Remote sensing and spectral analysis of plumes from ocean dumping in the New York Bight Apex

The application of the remote sensing techniques of aerial photography and multispectral scanning in the qualitative and quantitative analysis of plumes from ocean dumping of waste materials is investigated in the New York Bight Apex. Plumes resulting from the dumping of acid waste and sewage sludge were observed by Ocean Color Scanner at an altitude of 19.7 km and by Modular Multispectral Scanner and mapping camera at an altitude of 3.0 km. Results of the qualitative analysis of multispectral and photographic data for the mapping, location, and identification of pollution features without concurrent sea truth measurements are presented which demonstrate the usefulness of in-scene calibration. Quantitative distributions of the suspended solids in sewage sludge released in spot and line dumps are also determined by a multiple regression analysis of multispectral and sea truth data.

Johnson, R. W.↗
DOE OSTI2019

Risk factors, clinical outcomes, and natural history of uveal melanoma: a single-institution analysis

Uveal melanoma (UM) is the most common primary intraocular malignancy in adults. We describe the characteristics of UM patients at a tertiary referral center in the Mid-Southern United States, and explore associations and predictors of outcomes. This is a retrospective cohort study of patients with UM seen at West Cancer Center, from 07/2006 to 08/2017. Clinical characteristics and their relationship to outcomes (time-to-death and metastasis) were explored using Cox regression analysis. We identified 208 patients, 51% males, 97% Caucasians, 80% were symptomatic, with a median follow-up of 2.34 years, IQR (1.01–3.03), of which 19.2% died during follow-up. Metastases were diagnosed in 19% (4 older patients had metastases at diagnosis), 53% of those by surveillance. Without considering metastases as a time-varying covariate, age (HR = 1.06/year, CI 1.0–1.1; p < 0.001), headaches (HR = 5.7, CI 1.6–20.5; p = 0.03), and tumor stage (T) were significant covariates for time-to-death. Tumor stages T3 versus T1 (HR = 6.4; CI 1.5–27.7; p = 0.01) and T4 versus T1 (HR = 5.98; CI 1.3–27.8; p = 0.02) were associated with worse outcomes. When considering metastases as a time-varying covariate (HR = 35.8, CI 17–75.2; p < 0.001), only age remains in the model (HR = 1.04/year; p < 0.001). However, tumor stage (p < 0.001), headaches (p = 0.008), and age (p < 0.001) are associated with time-to-metastasis. One in five patients developed metastasis which was the most influential factor on mortality. Predictors of mortality were metastasis, age, tumor stage, and headache as a reported symptom. Surveillance successfully diagnosed metastatic disease in most patients. Most patients had symptoms preceding their UM diagnosis highlighting an opportunity for earlier recognition of UM.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2020

Lessons Learnt from Comparing WhatsApp Privacy Concerns Across Saudi and Indian Populations

The purpose of this study is to understand the privacy concerns and behavior of non-WEIRD populations in online messaging platforms. Analysis of surveys (n=674) of WhatsApp users in Saudi Arabia and India revealed that Saudis had significantly higher concerns about being contacted by strangers. In contrast, Indians showed significantly higher concerns with respect to social contact from professional colleagues. Demographics impinge privacy preferences in both populations, but in different ways. Results from regression analysis show that there are statistically significant differences between the privacy behaviors of Saudis and Indians. In both cases, privacy concerns were strongly correlated with their reported privacy behaviors. Despite the differences, we identified technical solutions that could address the concerns of both populations of participants. We close by discussing the applicability of our recommendations, specifically those on transparency and consent, to other applications and domains.

Dev, Jayati↗
NASA NTRS2004

Uncertainty Analysis on Heat Transfer Correlations for RP-1 Fuel in Copper Tubing

NASA is studying kerosene (RP-1) for application in Next Generation Launch Technology (NGLT). Accurate heat transfer correlations in narrow passages at high temperatures and pressures are needed. Hydrocarbon fuels, such as RP-1, produce carbon deposition (coke) along the inside of tube walls when heated to high temperatures. A series of tests to measure the heat transfer using RP-1 fuel and examine the coking were performed in NASA Glenn Research Center's Heated Tube Facility. The facility models regenerative cooling by flowing room temperature RP-1 through resistively heated copper tubing. A Regression analysis is performed on the data to determine the heat transfer correlation for Nusselt number as a function of Reynolds and Prandtl numbers. Each measurement and calculation is analyzed to identify sources of uncertainty, including RP-1 property variations. Monte Carlo simulation is used to determine how each uncertainty source propagates through the regression and an overall uncertainty in predicted heat transfer coefficient. The implications of these uncertainties on engine design and ways to minimize existing uncertainties are discussed.

Driscoll, E. A.↗
DOE OSTI2018

An Intraseasonal Mode of Atmospheric Variability Relevant to the U.S. Hydroclimate in Boreal Summer: Dynamic Origin and East Asia Connection

In this work intraseasonal modes of atmospheric variability over the Northern Hemisphere (NH) midlatitudes in boreal summer are identified via an empirical orthogonal function (EOF) analysis of the daily 10–90-day bandpass-filtered 250-hPa streamfunction for the period of 1950–2016. The first two EOF modes are characterized, respectively, by (i) a single-signed streamfunction anomaly that extends across the NH and (ii) a regional dipole structure with centers over the Aleutian Islands and northeastern Pacific. The third EOF mode (EOF-3) is a quasi-stationary wave train over the Pacific–North American sector with an equivalent barotropic structure in the vertical. EOF-3 is associated with a northwest–southeast oriented anomalous precipitation dipole over the United States. A nonmodal instability analysis of the boreal summer climatological flow in terms of the 250-hPa streamfunction reveals that one of the top “optimal mode” disturbances mimicking the EOF-3 structure grows from an initial precursor disturbance over East Asia through extracting kinetic energy from background flow and attains its maximum amplitude in around nine days. An additional lag regression analysis illustrates that anomalous latent heating associated with cloud and precipitation formation over East Asia is responsible for generating the precursor disturbance for the EOF-3-like optimal mode. This result suggests the existence of an important connection between the hydrological cycles of East Asia and North America, which is dynamically intrinsic to the boreal summer upper-tropospheric flow. Knowledge of such a connection will help us better understand and model hydroclimate variability over these two continents.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1988

Production of Be-10 in stony meteorites - Composition dependence

The relationship between the production rate of Be-10 in stony meteorites and its element composition was investigated by measuring the contents of Be-10 in 21 samples from 17 meteorites with known major-element composition, and comparing the experimental Be-10 values with those obtained by the regression analysis. The Be-10 production was modeled by the equation of Stauffer (1962). The measured Be-10 contents were found to range from 16 dpm/kg in the oxygen- and magnesium-poor eucrites and the Indarch meteorite to 28 dpm/kg in the oxygen- and magnesium-rich aubrites and the mineral separates from Bruderheim. Using the regression analyses and taking in account various corrections, an equation was obtained which reproduces the measured Be-10 content with an accuracy of about 10 percent.

Moniot, R. K.↗
DOE OSTI2020

Improved Parametric Models for Explosion Pressure Signals Derived From Large Datasets

Accurate recording and characterization of explosion-induced pressure signals are key components of the forensic analysis of explosion events in the atmosphere. Parametric overpressure models based on several key waveform features (peak overpressure, positive pulse duration, and impulse) are widely used to estimate explosion energy in terms of trinitrotoluene equivalent yield. However, those models are often developed by a limited dataset, including only a few events or recordings at relatively short propagation distances. Here, we develop empirical waveform-parameter models based on a regression analysis of a large set of data curated from four chemical explosion experiments including 16 detonations. We measured peak overpressure and impulse for positive and negative phases from 1000 pressure signals recorded at local ranges (<20 km) with scaled distance up to 8000 m/kg 1/3 . Additionally, the measured waveform parameters showed large variation with respect to observing distances indicating the effects of atmospheric propagation. In this study, a second-order polynomial model was used in a least-squares regression to account for those propagation effects and to improve data fitting. In addition to model parameters for waveform features, we also determined range-dependent model uncertainties based on data variance. The model uncertainty represents the prediction error of our models and can be critical to evaluating the uncertainty of yield estimate.

58 GEOSCIENCES↗
DOE OSTI2023

Carbon cycle extremes accelerate weakening of the land carbon sink in the late 21st century

Increasing surface temperature could lead to enhanced evaporation, reduced soil moisture availability, and more frequent droughts and heat waves. The spatiotemporal co-occurrence of such effects further drives extreme anomalies in vegetation productivity and net land carbon storage. However, the impacts of climate change on extremes in net biospheric production (NBP) over longer time periods are unknown. Using the percentile threshold on the probability distribution curve of NBP anomalies, we computed negative and positive extremes in NBP. Here we show that due to climate warming, about 88% of global regions will experience a larger magnitude of negative NBP extremes than positive NBP extremes toward the end of 2100, which accelerate the weakening of the land carbon sink. Our analysis indicates the frequency of negative extremes associated with declines in biospheric productivity was larger than positive extremes, especially in the tropics. While the overall impact of warming at high latitudes is expected to increase plant productivity and carbon uptake, high-temperature anomalies increasingly induce negative NBP extremes toward the end of the 21st century. Using regression analysis, we found soil moisture anomalies to be the most dominant individual driver of NBP extremes. The compound effect of hotness, dryness, and fire caused extremes at more than 50% of the total grid cells. The larger proportion of negative NBP extremes raises a concern about whether the Earth is capable of increasing vegetation production with a growing human population and rising demand for plant material for food, fiber, fuel, and building materials. The increasing proportion of negative NBP extremes highlights the consequences not only of reduction in total carbon uptake capacity but also of conversion of land to a carbon source.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1973

OAO battery data analysis

Summary, consolidation and analysis of specifications, manufacturing process and test controls, and performance results for OAO-2 and OAO-3 lot 20 Amp-Hr sealed nickel cadmium cells and batteries are reported. Correlation of improvements in control requirements with performance is a key feature. Updates for a cell/battery computer model to improve performance prediction capability are included. Applicability of regression analysis computer techniques to relate process controls to performance is checked.

Gaston, S.↗
NASA NTRS1987

Analysis of relativistic nucleus-nucleus interactions in emulsion chambers

The development of a computer-assisted method is reported for the determination of the angular distribution data for secondary particles produced in relativistic nucleus-nucleus collisions in emulsions. The method is applied to emulsion detectors that were placed in a constant, uniform magnetic field and exposed to beams of 60 and 200 GeV/nucleon O-16 ions at the Super Proton Synchrotron (SPS) of the European Center for Nuclear Research (CERN). Linear regression analysis is used to determine the azimuthal and polar emission angles from measured track coordinate data. The software, written in BASIC, is designed to be machine independent, and adaptable to an automated system for acquiring the track coordinates. The fitting algorithm is deterministic, and takes into account the experimental uncertainty in the measured points. Further, a procedure for using the track data to estimate the linear momenta of the charged particles observed in the detectors is included.

Mcguire, Stephen C.↗
NASA NTRS1988

An analysis of penetration and ricochet phenomena in oblique hypervelocity impact

An experimental investigation of phenomena associated with the oblique hypervelocity impact of spherical projectiles on multisheet aluminum structures is described. A model that can be employed in the design of meteoroid and space debris protection systems for space structures is developed. The model consists of equations that relate crater and perforation damage of a multisheet structure to parameters such as projectile size, impact velocity, and trajectory obliquity. The equations are obtained through a regression analysis of oblique hypervelocity impact test data. This data shows that the response of a multisheet structure to oblique impact is significantly different from its response to normal hypervelocity impact. It was found that obliquely incident projectiles produce ricochet debris that can severely damage panels or instrumentation located on the exterior of a space structure. Obliquity effects of high-speed impact must, therefore, be considered in the design of any structure exposed to the meteoroid and space debris environment.

Schonberg, William P.↗
NASA NTRS1988

Analysis of oblique hypervelocity impact phenomena

This paper describes the results of an experimental investigation of phenomena associated with the oblique hypervelocity impact of spherical projectiles on multisheet aluminum structures. A model that can be employed in the design of meteoroid and space debris protection systems for space structures is developed. The model consists of equations that relate crater and perforation damage of a multisheet structure to parameters such as projectile size, impact velocity, and trajectory obliquity. The equations are obtained through a regression analysis of oblique hypervelocity impact test data. This data shows that the response of a multisheet structure to oblique impact is significantly different from its response to normal hypervelocity impact. It was found that obliquely incident projectiles produce ricochet debris that can severely damage panels or instrumentation located on the exterior of a space structure. Obliquity effects of high-speed impact must, therefore, be considered in the design of any structure exposed to a meteoroid or space debris environement.

Schonberg, William P.↗
DOE OSTI2018

Three differential expression profiles of miRNAs as potential biomarkers for lung adenocarcinoma

Highlights: • To identify the differential miRNAs expression between lung cancer and normal tissues. • Data analysis was based on a computational approach to detect survival-associated signatures. • Three-miRNA signature could be used as a prognostic marker in LACA. Owing to the poor prognosis, novel biomarkers for lung adenocarcinoma (LACA) are needed nowadays. The aim of the study was to identify the differential miRNAs expression between lung cancer and normal tissues and evaluate the prognostic values of the miRNAs. Multidimensional data of 528 samples were retrieved from The Cancer Genome Atlas archive. Data analysis was based on a computational approach to detect survival-associated molecular signatures. A total of 191 differentially expressed miRNAs were identified between LACA tissues and normal tissues, including 88 up-regulated and 103 down-regulated miRNAs. The Kaplan-Meier survival method revealed the prognostic function of the three miRNAs (miR-1293, miR-873 and miR-1914). Cox regression analysis showed that the three-miRNA signature was an independent prognostic factor in LACA. The functional enrichment analysis suggested that the target genes of three miRNAs may be involved in various pathways related to the cancer. This study demonstrated that the three-miRNA signature (miR-1293, miR-873 and miR-1914) could be used as a prognostic marker in LACA.

60 APPLIED LIFE SCIENCES↗