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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Chlorophyll fluorescence is a potential indicator to measure photochemical efficiency in early to late soybean maturity groups under changing day lengths and temperatures

In this study, we employed chlorophyll a fluorescence technique, to indicate plant health and status in response to changing day lengths (photoperiods) and temperatures in soybean early and late maturity groups. Chlorophyll a fluorescence study indicates changes in light reactions in photosystem II. Experiments were performed for 3-day lengths (12.5, 13.5, and 14.5 h) and five temperatures (22/14°C, 26/18°C, 30/22°C, 34/26°C, and 40/32°C), respectively. The I-P phase declined for changing day lengths. Active reaction centers decreased at long day length for maturity group III. We observed that low temperatures impacted the acceptor side of photosystem II and partially impacted electron transport toward the photosystem I end electron acceptor. Results emphasized that higher temperatures (40/32°C) triggered damage at the oxygen-evolving complex and decreased electron transport and photosynthesis. We studied specific leaf areas and aboveground mass. Aboveground parameters were consistent with the fluorescence study. Chlorophyll a fluorescence can be used as a potential technique for high-throughput phenotyping methods. The traits selected in the study proved to be possible indicators to provide information on the health status of various maturity groups under changing temperatures and day lengths. These traits can also be deciding criteria for breeding programs to develop inbreed soybean lines for stress tolerance and sensitivity based on latitudinal variations.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2024

Agent-based simulations of shared automated vehicle operations: reflecting travel-party size, season and day-of-week demand variations

Here, this paper explores the effects of day of week and season of year demand variations for shared rides, along with realistic travel party sizes, on shared autonomous vehicle (SAV) services across the Austin, Texas region. Using the agent-based POLARIS program, synthetic person-trips that reflect travel-party size (from one to four persons) and demand variations over days and months, as evident in the National Household Travel Survey data were simulated in each scenario over a 24 h travel day. Results show that realistic party sizes can bring considerable changes to SAV fleet performance, including up to 8.5% higher service rates (number of requests accepted within 15 min), 5 min shorter journey times (wait time + travel time), 28% higher vehicle occupancies on weekends, and roughly 4% lower empty fleet VMT. Weekend travel is most impacted by season of year, with weekday travel patterns looking more uniform (thanks to work and school trips). Various performance metrics for the Austin network, like total and empty VMT, change by up to 30% when considering realistic variations in party size and time of year. This paper underscores the value of recognizing day-to-day and month-to-month variations in travel demand, and the importance of agent-based model equations to reflect travel-party size. Such realism can help quantify SAV seat occupancies more accurately, highlighting the importance of shared mobility. However, it also creates demand and supply issues for operators that now need more information on party size to manage dynamic ride-sharing, or those that may wish to shift their fleet vehicles to other regions for special events to protect profits while offering reasonable wait times to customers throughout the year.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2023

Evaluation of present-day extreme precipitation over the United States: an inter-comparison of convection and dynamic permitting configurations of E3SMv1

Abstract Accurate simulation of the present-day characteristics of mean and extreme precipitation at regional scales remains a challenge for Earth system models, which is due in part to deficiencies in model physics such as convective parameterization (CP), and coarse resolution. High horizontal resolution (HR, ∼25 km) and multiscale modeling framework (MMF, i.e. replacing conventional CP with embedded km-scale cloud-resolving models) are two promising directions that could help improve the interaction between subgrid-scale physical processes and large-scale climate. Here, we evaluate simulated extreme precipitation over the United States (US) across three configurations (i.e. low-resolution [LR], HR, and MMF) of the Energy Exascale Earth System Model (E3SMv1) and intercompare them against two gridded observation datasets (climate prediction center daily US precipitation and integrated multi-satellite retrievals for global precipitation measurement). We assess the model’s ability to simulate very heavy seasonal precipitation (illustrated by the difference between the 99th and 90th percentile values) as well as the spatial distributions of several extreme precipitation indices defined by the expert team on climate change detection and indices. Our results show that both the dry (i.e. consecutive dry days (CDD)) and wet (i.e. consecutive wet days, maximum 5 day precipitation, and very wet days) extremes evaluated herein show some improvement as well as degradation with MMF and HR relative to LR. These results vary across seasons and US subregions. For instance, only the very heavy precipitation of winter is improved with MMF and HR. Both configurations alleviate the well-known drizzling bias evident in LR across both winter and summer in many parts of the US, largely due to the overall improvement in intensity and frequency of precipitation. Additionally, our results suggest that while E3SMv1-MMF has higher intensity rates when it does rain, it has too many CDD during the summer, contributing to a low mean precipitation bias.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

Predicting peak day and peak hour of electricity demand with ensemble machine learning

Battery energy storage systems can be used for peak demand reduction in power systems, leading to significant economic benefits. Two practical challenges are 1) accurately determining the peak load days and hours and 2) quantifying and reducing uncertainties associated with the forecast in probabilistic risk measures for dispatch decision-making. In this study, we develop a supervised machine learning approach to generate 1) the probability of the next operation day containing the peak hour of the month and 2) the probability of an hour to be the peak hour of the day. Guidance is provided on preparation and augmentation of data as well as selection of machine learning models and decision-making thresholds. The proposed approach is applied to the Duke Energy Progress system and successfully captures 69 peak days out of 72 testing months with a 3% exceedance probability threshold. On 90% of the peak days, the actual peak hour is among the 2 h with the highest probabilities.

25 ENERGY STORAGE↗
DOE OSTI2024

Global Corn Heat Stress: Mean and SD of Degree Days Above 29°C based on NEX-GDDP-CMIP6 Climate Projections

Description This global dataset provides the estimated mean and standard deviation (SD) of corn heat stress (degree days above 29°C) for a set of climate models in NEX-GDDP-CMIP6 at 0.25-degree resolution. The NEX-GDDP-CMIP6 dataset is comprised of global downscaled climate scenarios derived from the General Circulation Model (GCM) runs conducted under the Coupled Model Intercomparison Project Phase 6 (CMIP6). The current dataset includes: Long-Term Average Degree Days Above 29°C- Historical Long-Term Average Degree Days Above 29°C- SSP245 Long-Term Standard Deviation of Degree Days Above 29°C- Historical Long-Term Standard Deviation of Degree Days Above 29°C- SSP245 The mean and SD are calculated over 1985-2014 for the historical period and over 2035-2064 for future projections. A full description of methods, including growing season, daily temperature distribution, and statistical coefficients, can be found in Haqiqi (2024). The source climate data are obtained from https://ds.nccs.nasa.gov/thredds2/catalog/catalog.html and are described in Thrasher et al (2022). The codes used to create this dataset are available at https://github.com/ihaqiqi/dd29c_nex_cmip6. Acknowledgments This work was supported by the US Department of Energy, Office of Science, Biological and Environmental Research Program, Earth and Environmental Systems Modeling, MultiSector Dynamics under Cooperative Agreement DE-SC0022141. The data processing, computation, and storage were completed on Purdue Anvil supercomputer and cyberinfrastructure supported by the National Science Foundation HDR award # 2118329: "NSF Institute for Geospatial Understanding through an Integrative Discovery Environment (I-GUIDE)". References Haqiqi. I. (2024). Trade can buffer climate-induced risks and volatilities in crop supply. Environmental Research: Food Systems. https://doi.org/10.1088/2976-601X/ad7d12 Thrasher, B., Wang, W., Michaelis, A., Melton, F., Lee, T., & Nemani, R. (2022). NASA global daily downscaled projections, CMIP6. Scientific Data, 9(1), 262. https://doi.org/10.1038/s41597-022-01393-4

Climate Change↗
NASA NTRS1972

Effect of a 30-day isolation stress on calcium, phosphorus and other excretory products in an unrestrained chimpanzee.

An unrestrained chimpanzee was studied in an isolation chamber and in his home cage environment. The study consisted of 49 urine collection days (14 days pre-, 5 days post- and 30 days of isolation), and then of 10 days in the home cage. Dietary intake, urine and fecal data were obtained. The effect of isolation on various excretory parameters was studied. Urine samples were analyzed for volume, osmolarity, creatinine, creatine, urea-N, 17-hydroxy corticosteroids, VMA, calcium and inorganic phosphorus. One way analyses of variance performed on the urinary excretion parameters showed all except creatinine excretion to vary significantly during periods of the study. The changes observed in calcium and phosphorus were highly significant. The data suggests that the calcium to phosphorus excretion ratio might serve as a physiological stress indicator of Selye's adaptation syndrome (period of resistance).

Sabbot, I. M.↗
NASA NTRS1975

Spectral analysis of skeletal muscle changes resulting from 59 days of weightlessness in Skylab 2

During stressful exercise of the m. gastrocnemius, preflight and postflight surface electromyograms (EMG) were taken from each of the Skylab II astronauts. Measurements on the muscle were made once 5 days before launch, and four times postflight on recovery day, 4 days after recovery, 16 days after recovery and 29 days after recovery. It was hypothesized that the disused gastrocnemius would exhibit dysfunction characteristics similar to those found in laboratory studies on disuse and of pathologically astrophied muscle, and that physical stress would be associated with heightened fatigability in the muscle. Both hypotheses were sustained. The results showed significant shifts of the predominant frequency of the gastrocnemius into higher than normal bands which suggests a relationship between muscle disuse characteristics and pathologic dysfunction characteristics. It was concluded that the spectrally analyzed EMG is a sensitive measure of muscle dsyfunction that is associated with disuse. Antigravity muscles exhibit heightened susceptibility to fatigue when subjected to lengthy weightlessness.

Lafevers, E. V.↗
NASA NTRS1979

Continuous metabolic and cardiovascular measurements on a monkey subject during a simulated 6-day Spacelab mission

A 10-kg male pig-tailed monkey (Macaca nemestrina) was selected as an optimal species for spaceflight studies on weightlessness. Three days before the simulated launch, the animal was placed in a fiberglass pod system to provide continuous measurement of respiratory gas exchange. Attention is given to examining the effects of weightlessness on several basic parameters of metabolic and cardiovascular function in an adult nonhuman primate. The 10.7-day total simulated-experiment period consisted of preflight 2.6 days, inflight 6.3 days, and postflight 1.8 days. Statistically significant diurnal variation was noted in oxygen consumption and CO2 production rates, body temperature and HR, but not in respiratory quotient or blood pressure. The high quality of the continuous data obtained demonstrates the feasibility of performing sound physiological experimentation on nonhuman primates in the Spacelab environment.

Pace, N.↗
NASA NTRS1983

X Persei - Optical polarization variation on the 580 day binary-like period

Observations of periodicities in the optical polarization of the weak X-ray source X Persei are reported. Polarization was measured in the V band 400 times over the course of 356 nights during 1977-1982. The Q and U Stokes parameters derived from the measurements show a definite variability with a typical amplitude of 0.1%, which is strongest at periods greater than 100 days. In particular, a strong peak is observed with a period of 297 days, consistent with the second-harmonic component of the known 580-day radial velocity cycle. A component with 590-day periodicity is not ruled out by the observations, although it was not detected. Observations imply the 580-day period to be an effect of orbital or rotational processes, with the corotating scattering body either close to the light source or very large in extent, and a system inclination close to 80 deg.

Kemp, J. C.↗
NASA NTRS1985

Research on the effect of noise at different times of day: Models, methods and findings

Social surveys of residents' responses to noise at different times of day are reviewed. Some of the discrepancies in published reports about the importance of noise at different times of day are reduced when the research findings are classified according to the type of time of day reaction model, the type of time of day weight calculated and the method which is used to estimate the weight. When the estimates of nighttime weights from 12 studies are normalized, it is found that they still disagree, but do not support stronger nighttime weights than those used in existing noise indices. Challenges to common assumptions in nighttime response models are evaluated. Two of these challenges receive enough support to warrant further investigation: the impact of changes in numbers of noise events may be less at night than in the day and nighttime annoyance may be affected by noise levels in other periods. All existing social survey results in which averages of nighttime responses were plotted by nighttime noise levels are reproduced.

Fields, J. M.↗
NASA NTRS1985

Study of spectral exponent on quiet and disturbed days

The spectral exponents of the diurnal and semidiurnal anisotropies are studied on quiet and disturbed days for a period from 1964 to 75. It has been observed for the diurnal anisotropy that the spectral exponent for quiet days is 0.0 from 1964 to 70, however during 1971 and onwards its value is found different from zero and is -0.4; for disturbed days the spectral exponent is observed to be 0.0 from 1964 to 75 with an exception of the year 1966. Further, it has been observed for the semi-diurnal anisotropy that the best value for the spectral exponent on quiet days being + 0.6 from 1964 to 74; however on disturbed days the value of spectral exponent is sometimes negative or positive but different from zero. It was derived from the present investigation that superimposed on the corotational anisotropy, expected from a balance between outward radial convection and inward field aligned diffusion, there is an additional component operating during the period under consideration.

Kumar, S.↗
NASA NTRS1989

Solar or meteorological control of lower ionospheric fluctuations (2-15 and 27 days) in middle latitudes

Several types of short and long term effects of solar activity on the lower ionosphere are related to solar flares, the sector structure of the interplanetary magnetic field and some periodicities in sunspots or solar radio flux. The most evident periodicities of the Sun are the 11 year cycle of its activity and the differential rotation period near 27 days (25 to 30 days). Here, the following questions are discussed: which periods between 2 and 15 days and near 27 days occur in ionospheric absorption during the interval July 1980 to July 1985 and are these periods related to similar periods in solar Ly-alpha flux, geomagnetic activity, or neutral wind near 95 km observed in Collm (GDR). Day-time absorption data obtained by the A3 method was used for the following radio-paths: (164 kHz), (1539 kHz), (6090 kHz). With the use of these data the electron density variations in the lower ionosphere can be analyzed. An attempt was made to clarify the nature of the observed fluctuations in absorption.

Pancheva, D.↗
NASA NTRS1993

Gender differences in endocrine responses to posture and 7 days of 6 deg head down bed rest

Endocrine regulation of fluids and electrolytes during seven days of 6 deg head down bed rest (HDBR) was compared in male (n = 8) and, for the first time, female (n = 8) volunteers. The subjects' responses to quiet standing for 2 hr before and after HDBR were also tested. In both sexes, diuresis and natriuresis were evident during the first 2-3 days of HDBR, resulting in a marked increase in the urinary Na/K ratio and significant Na retention on reambulation. After the first day of HDBR, plasma renin activity (PRA) was increased relative to aldosterone, plasma volume was decreased, and the renal response to aldosterone appeared to be appropriate. Circulating levels of arginine vasopressin (AVP), cortisol, and ACTH were unchanged during HDBR. Plasma testosterone decreased slightly on day 2 of HDBR in males. The ratio of AM ACTH to cortisol was lower in females than in males because ACTH was lower in females. Urinary cortisol increased and remained elevated throughout the HDBR in males only. There were no gender differences in the responses to 7 day HDBR, except those in the pituitary-adrenal system; those differences appeared unrelated to the postural change. The provocative cardiovascular test of quiet standing before and after bed rest revealed both sex differences and effects of HDBR. There were significant sex differences in cardiovascular responses to standing, before and after HDBR. Females had greater PRA and aldosterone responses to standing before bedrest and larger aldosterone responses to standing after HDBR than males. Cardiovascular responses to standing before and after bedrest differed markedly: arterial pressure and heart rates increased with standing before HDBR, by contrast, arterial pressure decreased, with greater increases in heart rates after HDBR. In both sexes, all hormonal responses to standing were greater after HDBR. The results show clearly that similar responses to standing as well as to HDBR occur in both sexes, but that females exhibit greater PRA and aldosterone responses than males.

Vernikos, J.↗
NASA NTRS1994

Observations of the 5-day wave in the mesosphere and lower thermosphere

The 5-day planetary wave has been detected in the winds measured by the High Resolution Doppler Imager (HRDI) on the Upper Atmosphere Research Satellite (UARS) in the mesosphere and lower thermosphere (50-110 km). The appearances of the 5-day wave are transient, with a lifetime of 10-20 days in the two-year data set. The structures of selected 5-day wave events are in generally good agreement with the (1,1) Rossby normal mode for both zonal and meridional components. A climatology of the 5-day wave is presented for an altitude of 95 km and latitudes mainly between 40 deg S and 40 deg N.

Wu, D. L.↗
NASA NTRS1995

STS-84 Day 09 Highlights

On this the ninth day of the STS-84 mission, the flight crew, Cmdr. Charles J. Precourt, Pilot Eileen M. Collins, Payload Cmdr, Jean-Francois Clervoy (ESA), Mission Specialists Edward T. Lu, Carlos I. Noriega, Elena V. Kondakova, Jerry M. Linenger (download), and C. Michael Foale (upload) spend the morning testing Atlantis' flight control surfaces and thruster jets to ensure they are ready to support the Shuttle's high speed return to Earth. The astronauts' final day on orbit is devoted to stowing equipment and finishing experiment work in the Spacehab module in the cargo bay. In addition to 2,600 pounds of items being brought back from the Mir Space Station, Atlantis is ferrying home astronaut Jerry Linenger, who is returning to Earth after 122 days on the Mir. If Atlantis lands as planned Saturday, Linenger will have logged 132 days in space on this flight, the second longest single spaceflight by a U.S. astronaut behind the record 188-day stay in orbit by Shannon Lucid last year.

Source record↗
NASA NTRS2002

STS-109 Mission Highlights Resource Tape: Flight Days 1 - 3 - Part 1 of 4

This video, Part 1 of 4, shows the activities of the STS-109 crew (Scott Altman, Commander; Duane Carey, Pilot; John Grunsfeld, Payload Commander; Nancy Currie, James Newman, Richard Linnehan, Michael Massimino, Mission Specialists) during flight days 1 through 3. The activities from other flight days can be seen on 'STS 109 Mission Highlights Resource Tape' Part 2 of 4 (internal ID 2002137664), 'STS 109 Mission Highlights Resource Tape' Part 3 of 4 (internal ID 2002139471), and 'STS-109 Mission Highlights Resource Tape' Part 4 of 4 (internal ID 2002137577). The main activity recorded during flight day 1 is the liftoff of Columbia. Attention is given to suit-up, boarding, and pre-flight procedures. The pre-launch crew meal has no sound. The crew members often wave to the camera before liftoff. The jettisoning of the solid rocket boosters is shown, and the External Tank is seen as it falls to Earth, moving over African dunes in the background. There are liftoff replays, including one from inside the cockpit. The opening of the payload bay doors is seen from the rear of the shuttle's cockpit. The footage from flight day 2 shows the Flight Support System for bearthing the HST (Hubble Space Telescope). Crew preparations for the bearthing are shown. Flight day 3 shows the tracking of and approach to the HST by Columbia, including orbital maneuvers, the capture of the HST, and its lowering onto the Flight Support System. Many views of the HST are shown, including one which reveals an ocean and cloud background as the HST retracts a solar array.

Source record↗
NASA NTRS2003

STS-113 Mission Highlights Resource Tape Flight Days 4-6 Tape: 2 of 4

This video, Part 2 of 4, shows the activities of the crew of the Space Shuttle Endeavor on flight days 4-6 of STS-113. The crew consists of Commander Jim Wetherbee, Pilot Paul Lockhart, and Mission Specialists Michael Lopez-Alegria and John Herrington. On flight day 4, The P1 truss was transfered from Canadarm on Endeavour to Canadarm 2 on the ISS, and aligned with the S0 Truss for attachment. The mission specialists connected utility cables between the trusses on an extravehicular activity (EVA). Flight day 5 was Commander Wetherbee's 50th birthday, and the video includes a clip from The Tonight Show in which Jay Leno wishes him a happy birthday. Intravehicular activity on flight day 5 includes Peggy Whitsun of the outgoing Expedition 5 crew of the International Space Station (ISS) showing incoming Expedition 6 crew members Ken Bowersox and Don Pettit how to replace valves on the ISS CO2 removal system. The video also includes an interior tour of Endeavour and the ISS, and an brief exterior tour of the ISS. On flight day 6 Lopez-Alegria and Herrington attach a television antenna to the P1 truss, and are shown using a handcart on the truss several times. The video includes several Earth views, including one of the west coast of South America.

Source record↗
NASA NTRS1992

Shoot growth in aseptically cultivated daylily and haplopappus plantlets after a 5-day spaceflight

Plantlets of daylily (Hemerocallis cv. Autumn Blaze) regenerated from cell suspensions, and 4 clonal populations of Haplopappus gracilis were aseptically cultivated aboard the Shuttle "Discovery" during a 5-day mission within NASA's Plant Growth Unit (PGU) apparatus. Daylily was selected as a representative herbaceous perennial monocotyledon and the haplopappus clones represented an annual dicotyledon. The latter included 4 strains with different physiological and morphological characteristics: two aseptic seedling clones (each generated from a single seedling) and two tissue culture-derived lines. Mean daily growth rates for the primary shoots of all plantlets averaged 4.13 mm day-1 (SD = 2.20) for the flight experiment and 4.68 mm day-1 (SD = 2.59) for the ground control. Comparable growth rates calculated by summing both the primary and secondary shoots for all plantlets were 5.94 mm day-1 (SD = 2.89) for the flight experiment and 6.38 mm day-1 (SD = 3.71) for the control. Statistically significant differences existed between: (1) flight vs control primary shoot growth (the controls growing more than plantlets subjected to spaceflight conditions), (2) the different populations (the daylily gaining more shoot material than any of the haplopappus populations and the haplopappus seedling clones outperforming the tissue culture-derived haplopappus lines), and (3) the individual Plant Growth Chambers contained within the PGU. The data suggest that some spaceflight-associated factor(s) increased the tendency for primary shoot apices to degrade or senesce, resulting in the release of apical dominance and permitting the emergence of axillary branches, which subsequently partially compensated for the reduced primary axis growth. In addition to spaceflight-associated factors, the physiologically diverse nature of the experimental material as well as environmental heterogeneities within the culture apparatus contributed to the variation in growth results. The findings could explain some discrepancies reported from various plant culture experiments conducted in space.

short duration↗