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At least 109 records · Page 6

All sources NASA NTRS DOE OSTI

DOE OSTI2023

AmeriFlux FLUXNET-1F CA-Obs Saskatchewan - Western Boreal, Mature Black Spruce

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site CA-Obs Saskatchewan - Western Boreal, Mature Black Spruce. This is the FLUXNET version of the carbon flux data for the site CA-Obs Saskatchewan - Western Boreal, Mature Black Spruce produced by applying the standard ONEFlux (1F) software. Site Description - 53.98717° N, 105.11779° W, elavation of 628.94 m, BOREAS 1994, 1996, BERMS climate measurements began Dec. 1996 and flux measurements in Apr. 1999

Black, T. Andrew↗

DOE OSTI2023

AmeriFlux FLUXNET-1F CA-Qfo Quebec - Eastern Boreal, Mature Black Spruce

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site CA-Qfo Quebec - Eastern Boreal, Mature Black Spruce. This is the FLUXNET version of the carbon flux data for the site CA-Qfo Quebec - Eastern Boreal, Mature Black Spruce produced by applying the standard ONEFlux (1F) software. Site Description - 49.69247° N / 74.34204° W, elevation of 387 mm, 90 - 100 yr old Black Spruce, Jack Pine, feather moss

Margolis, Hank A.↗

DOE OSTI2026

AmeriFlux FLUXNET-1F CA-Na1 New Brunswick - 1967 Balsam Fir - Nashwaak Lake Site 01 (Mature balsam fir forest)

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site CA-Na1 New Brunswick - 1967 Balsam Fir - Nashwaak Lake Site 01 (Mature balsam fir forest). This is the FLUXNET version of the carbon flux data for the site CA-Na1 New Brunswick - 1967 Balsam Fir - Nashwaak Lake Site 01 (Mature balsam fir forest) produced by applying the standard ONEFlux (1F) software. Site Description - immature balsam fir forest

Bourque, Charles P.-A.↗

DOE OSTI2026

AmeriFlux FLUXNET-1F CA-Ojp Saskatchewan - Western Boreal, Mature Jack Pine

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site CA-Ojp Saskatchewan - Western Boreal, Mature Jack Pine. This is the FLUXNET version of the carbon flux data for the site CA-Ojp Saskatchewan - Western Boreal, Mature Jack Pine produced by applying the standard ONEFlux (1F) software. Site Description - 53.91634° N, 104.69203° W, elavation of 579.27 m, BOREAS 1994, BERMS climate measurements began Mar. 1997 and flux measurements Aug. 1999

Black, Andrew T. [University of British Columbia]↗

DOE OSTI2021

Maturation of Rhodobacter capsulatus Multicopper Oxidase CutO Depends on the CopA Copper Efflux Pathway and Requires the cutF Product (Final Report)

The goal is to achieve a comprehensive understanding of the nature, mechanism of function and biogenesis of c-type cytochromes and their oligomeric complexes. These cytochrome are ubiquitous heme proteins that are required for cellular bioenergetics, including photosynthesis (Ps) and respiration (Res), which are central to chemical energy (ATP) production by oxidative- and photophosphorylation. We contribute to the molecular characterization of individual and membrane-integral cytochromes as parts of Ps and Res electron transport (ET) pathways, using the facultative phototrophic bacteria of as excellent models for multidisciplinary investigations. Supported by this grant we discovered novel membrane-bound cytochromes and cyts c complexes that are important for Ps- and Res-ET. We worked out their biogenesis including maturation (covalent heme addition) and assembly of mature subunits into complexes. These involve fundamental process found virtually in all organisms and are fundamental processes with major significance to the “Photosynthetic Systems” program of DOE-BES, because the cytochromes are integral components of natural energy production systems. Elucidation of basic principles, and the knowledge gained by their study greatly impact on our ability to design, engineer, and create new natural, bio-hybrid, bio-inspired and artificial systems to better capture light, transduce and store its energy with improved efficacy and are of broad significance.

14 SOLAR ENERGY↗

DOE OSTI2024

SHASTA: Task 2.2: Sensor Development for Subsurface Hydrogen Storage Monitoring Technology Maturation and Commercialization Plan (TMCP)

In Task 2.2 under the SHASTA program, NETL is developing in-situ optical fiber sensors for real-time monitoring of hydrogen, methane, and chemical parameters such as pH at subsurface hydrogen storage conditions. This Technology Maturation and Commercialization Plan report will provide the summary of NETL sensor development and test results under the SHASTA program to meet the subsurface application requirements and proposed technology maturation and deployment plan, and commercialization potential.

08 HYDROGEN↗

DOE OSTI2025

Moving Beyond Direct Load Control: A Maturity Model for Realizing the Promise of Demand Flexibility

This report discusses a new maturity model that regulators and utilities can use to guide and expand demand flexibility programs and enable the resources to provide more grid services. The model has six demand flexibility categories: planning and design; customer engagement; program operations; evaluation, measurement and verification; distributed energy resource orchestration; and data infrastructure. Within each category, capabilities are identified and described on a maturity scale that ranges from performing below expectations to improving on best practices.

24 POWER TRANSMISSION AND DISTRIBUTION↗

DOE OSTI2022

A Coarse-Grained Model of Affinity Maturation Indicates the Importance of B-Cell Receptor Avidity in Epitope Subdominance

The elicitation of broadly neutralizing antibodies (bnAbs) is a major goal in the design of vaccines against rapidly-mutating viruses. In the case of influenza, many bnAbs that target conserved epitopes on the stem of the hemagglutinin protein (HA) have been discovered. However, these antibodies are rare, are not boosted well upon reinfection, and often have low neutralization potency, compared to strain-specific antibodies directed to the HA head. Different hypotheses have been proposed to explain this phenomenon. We use a coarse-grained computational model of the germinal center reaction to investigate how B-cell receptor binding valency affects the growth and affinity maturation of competing B-cells. We find that receptors that are unable to bind antigen bivalently, and also those that do not bind antigen cooperatively, have significantly slower rates of growth, memory B-cell production, and, under certain conditions, rates of affinity maturation. The corresponding B-cells are predicted to be outcompeted by B-cells that bind bivalently and cooperatively. We use the model to explore strategies for a universal influenza vaccine, e.g., how to boost the concentrations of the slower growing cross-reactive antibodies directed to the stem. The results suggest that, upon natural reinfections subsequent to vaccination, the protectiveness of such vaccines would erode, possibly requiring regular boosts. Collectively, our results strongly support the importance of bivalent antibody binding in immunodominance, and suggest guidelines for developing a universal influenza vaccine.

60 APPLIED LIFE SCIENCES↗

NASA NTRS1975

Remotely sensing wheat maturation with radar

The scattering properties of wheat were studied in the 8-18 GHz band as a function of frequency, polarization, incidence angle, and crop maturity. Supporting ground truth was collected at the time of measurement. The data indicate that the radar backscattering coefficient is sensitive to both radar system parameters and crop characteristics particularly at incidence angles near nadir. Linear regression analyses of the radar backscattering coefficient on both time and plant moisture content result in rather good correlation. Furthermore, by calculating the average time rate of change of the radar backscattering coefficient it is found that it undergoes rapid variations shortly before and after the wheat is harvested. Both of these analyses suggest methods for estimating wheat maturity and for monitoring the progress of harvest.

Bush, T. F.↗

NASA NTRS1975

Effects of maturation on the reflectance of the lunar regolith: Apollo 16 - A case study

Soils at the Apollo 16 site become progressively darker as the percentage of glassy agglutinates increases. Magnetic separates of the agglutinate fraction of a soil are always darker than the bulk soil and are darker than the nonagglutinate fraction consisting of rock and mineral fragments. Darkening of a soil with maturity is due mainly to the increasing proportion of agglutinates. Coating of rock and mineral fragments with thin deposits of glass aids darkening in a minor way, but most of these particles eventually are destroyed by melting as the soils mature.

Adams, J. B.↗

NASA NTRS1977

Soil maturity and planetary regoliths - The Moon, Mercury, and the asteroids

Observations of the Moon, Mercury and the asteroids provide data which can be used to assess current ideas about the optical maturation of regoliths of bodies without atmospheres. Telescopic data show Mercury's surface to be as optically mature as the Moon's while the asteroids appear to have 'fresh' surfaces. We suggest that these cases illustrate two different paths of regolith evolution caused by differing micrometeoroid impact velocities, gravity, and in some cases composition.

Matson, D. L.↗

NASA NTRS1978

Primordial Pb, radiogenic Pb and lunar soil maturation

Pb-204 is directly correlated with the reduced Fe measured by ferromagnetic resonance. A similar correlation has been noted for hydrolyzable carbon (Pillinger et al., 1974). An enrichment of these elements appears to have occurred during soil maturation. In contrast to Pb-204, radiogenic Pb is reported to be lost during soil maturation (Church et al., 1976). Radiogenic Pb is present in mineral grains and may be lost by solar wind sputtering (or volatilization) and not resupplied. Pb-204 coating grain surfaces acts as a reservoir to provide the Pb-204 being extracted in the reduced Fe formation process. Venting or some other volatile release mechanism may replenish the surface-related Pb-204.

Reed, G. W., Jr.↗

NASA NTRS1982

Bone growth and composition in weanling and mature rats exposed to chronic centrifugation

The primary objective of the study is to determine the effect of continuous exposure to hypergravity on the development and composition of weight-bearing bone. The experimental results are seen to suggest that many, if not all, of the changes observed in bone growth and composition derive from the retarded growth rate of the centrifuged rats. Both centrifuged weanling and mature rats exhibit a significant reduction in femur length and mass. The changes in femur size are more apparent in the weanlings since they are exposed to hypergravity during their most rapid phase of skeletal development. In addition to a slower growth rate, the body mass of the mature and weanling animals is reduced even further by the depletion of body fat. The rapid loss of body fat observed in rats and mice during centrifugation, it is found, can produce a prompt and significant rise in relative femur mass after two weeks of exposure. After adaptation to centrifugation, however, relative femur mass is similar to that of controls at four and eight weeks. At 18 weeks, the centrifuged rats again exhibit an increase in relative femur mass. It is thought that this increase in relative femur mass may be generated by the difference in fat deposition between the 1-G controls and the high-G rats.

Keil, L. C.↗

NASA NTRS1989

Maturity and geochemistry of the Van Serg core (79001/2) with implications for micrometeorite composition

The soil maturity and the concentration of Fe metal and 18 major and trace elements were determined along the length of the 79001/2 double drive tube collected near the Van Serg crater at the Apollo 17 station 9. Samples from the top 8.5 cm of the core are found to be very mature and to be enriched in Fe metal and siderophile elements compared to soil lower in the core. It is suggested that this enrichment may have resulted from a significant exposure at some time in the past. A soil component of metallic Fe may be related to micrometeorite impact.

Morris, R. V.↗

NASA NTRS1990

Effects of sea maturity on satellite altimeter measurements

For equilibrium and near-equilibrium sea states, the wave slope variance is a function of wind speed U and of the sea maturity. The influence of both factors on the altimeter measurements of wind speed, wave height, and radar cross section is studied experimentally on the basis of 1 year's worth of Geosat altimeter observations colocated with in situ wind and wave measurements by 20 NOAA buoys. Errors and biases in altimeter wind speed and wave height measurements are investigted. A geophysically significant error trend correlated with the sea maturity is found in wind-speed measurements. This trend is explained by examining the effect of the generalized wind fetch on the curves of the observed dependence. It is concluded that unambiguous measurements of wind speed by altimeter, in a wide range of sea states, are impossible without accounting for the actual degree of wave development.

Glazman, Roman E.↗

NASA NTRS1991

Remote compositional mapping of lunar titanium and surface maturity

Lunar ilmenite (FeTiO3) is a potential resource capable of providing oxygen for life support and spacecraft propellant for future lunar bases. Estimates of TiO2 content in mature mare soils can be made using an empirical relation between the 400/500 nm reflectance ratio and TiO2 wt percent. A TiO2 abundance map was constructed for the entire near-side lunar maria accurate to + or - 2 wt percent TiO2 using CCD images obtained at the Tumamoc Hill 0.5 m telescope in Tucson, employing bandpass filters centered at 400 and 560 nm. Highest TiO2 regions in the maria are located in western Mare Tranquillitatis. Greater contrast differences between regions on the lunar surface can be obtained using 400/730 nm ratio images. The relation might well be refined to accommodate this possibly more sensitive indicator of TiO2 content. Another potential lunar resource is solar wind-implanted He-3 which may be used as a fuel for fusion reactors. Relative soil maturity, as determined by agglutinate content, can be estimated from 950/560 nm ration images. Immature soils appear darker in this ratio since such soils contain abundant pyroxene grains which cause strong absorption centered near 950 nm due Fe(2+) crystal field transitions. A positive correlation exists between the amount of He-3 and TiO2 content in lunar soils, suggesting that regions high in TiO2 should also be high in He-3. Reflectance spectrophotometry in the region 320 to 870 nm was also obtained for several regions. Below about 340 nm, these spectra show variations in relative reflectance that are caused by as yet unassigned near-UV absorptions due to compositional differences.

Johnson, J. R.↗

NASA NTRS1993

Growing wheat to maturity in reduced gas pressures

The main objective of this project was to determine assimilation of CO2 and efficiency of water use in wheat grown to maturity in a low pressure total gas pressure environment. A functional test of the low pressure plant growth chamber system was accomplished in February and March of 1993 wherein this objective was partially achieved. Plants were grown to maturity in the chambers. Data were actively collected during the first 29 days. The plants were allowed to maintain themselves at the CO2 compensation point until day 45 of the study at which point active atmospheric regulation was resumed. This provided data at the vegetative and reproductive stages of the life cycle of the plants. However, this information may not be representative of the performance of the plants due to the loss of low pressure on a number of days during the study, which affected the plants by changing the pressure potential of the tissues. The performance of the system will be discussed on a component by component basis. The maintenance of the plants at the CO2 compensation point was driven by the failure of the computer program operating the system. The software problems that arose during the functional test have since been corrected. Results from the functional test also indicated that the plants were not receiving adequate light and nutrients. The growth chambers have been relocated and the growth room modified to compensate for these deficiencies.

Rykiel, Edward J., Jr.↗

NASA NTRS1996

Calcium Balance in Mature Rats Exposed to a Space Flight Model

Negative calcium balances are seen in humans during spaceflight and bed rest, an analog of space flight. Due to the infrequency and costliness of space flight and the difficulties, cost, and restraints in using invasive procedures in bed rest studies, several ground based animal models of space flight have been employed. The most useful and well developed of these models is hind limb unloading in the rat. In this model the hind limbs are non-weight bearing (unloaded) but still mobile; there is a cephalad fluid shift similar to that seen in astronauts in flight; the animals are able to feed, groom and locomote using their front limbs; the procedure is reversible; and, importantly, the model has been validated by comparison to space flight. Several laboratories have studied calcium balance using rats in hind limb unweighting. Roer and Dillaman used young male rats to study calcium balance in this model for 25 days. They found no differences in dietary calcium intake, percent calcium absorption, urinary and fecal excretion, hence indicating no differences in calcium balance between control and unloaded rats. In another study, employing 120 day old females, rats' hind limbs were unloaded for 28 days. While negative calcium balances were observed during a 25 day recovery period no balance measurements were possible during unweighting since the researchers did not employ appropriate metabolic cages. In a recent study from this laboratory, using 200 g rats in the space flight model for two weeks, we found depressed intestinal calcium absorption and increased fecal calcium excretion (indicating less positive calcium balances) and lower circulating 1,25-dihydroxyvitamin D. The above studies indicate that there remains a dearth of information on calcium balance during the hind limb unloading rat space flight model, especially in mature rats, whose use is a better model for planned manned space flight than juvenile or growing animals. With the aid of a newly designed metabolic cage developed in our laboratory it is now possible to accurately measure urinary and fecal calcium excretions in this space flight model. The purpose of this study, then, was to extend and enlarge our previous findings viz: to measure calcium balances in mature rats exposed to a space flight model.

Wolinsky, Ira↗