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At least 775 records · Page 43
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Evaluating the Effects of Precipitation and Evapotranspiration on Soil Moisture Variability Within CMIP5 Using SMAP and ERA5 Data

=The effects of precipitation (Pr) and evapotranspiration (ET) on surface soil moisture (SSM) play an essential role in the land-atmosphere system. Here we evaluate multimodel differences of these effects within the Coupled Model Intercomparison Project Phase 5 (CMIP5) compared to Soil Moisture Active Passive (SMAP) products and ECMWF Reanalysis v5 (ERA5) as references in a frequency domain. The variability of SSM, Pr, and ET within three frequency bands (1/7 ~ 1/30 days -1 , 1/30 ~ 1/90 days -1 , and 1/90 ~ 1/365 days -1 ) after normalization is quantified using Fourier transform. We analyze the impact of ET and Pr on SSM variability based on a transfer function assuming that these variables form a linear time-invariant (LTI) system. For the total effects of ET and Pr on SSM variability, the CMIP5 estimations are smaller than the reference data in the two higher frequency bands and are larger than the reference data in the lowest frequency band. Besides, the effects on SSM by Pr and ET are found to be different across the three frequency bands. In each frequency band, the variability of the factor that dominates SSM (i.e., Pr or ET) from CMIP5 is smaller than that from the references. This study identifies the spatiotemporal distribution of differences between CMIP5 models and references (SMAP and ERA5) in simulating ET and Pr effects on SSM within three frequency bands. This study provides insightful information on how soil moisture variability is affected by varying precipitation and evapotranspiration at different time scales within Earth System Models.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

GIF Gas Cooled Fast Reactor: Proliferation Resistance and Physical Protection White Paper

This white paper represents the status of Proliferation Resistance and Physical Protection (PR&PP) characteristics for the Gas-cooled Fast reactor (GFR) reference designs selected by the Generation IV International Forum (GIF) GFR System Steering Committee (SSC). The intent is to generate preliminary information about the PR&PP features of the GFR reactor technology and to provide insights for optimizing their PR&PP performance for the benefit of GFR system designers. It updates the GFR analysis published in the 2011 report “Proliferation Resistance and Physical Protection of the Six Generation IV Nuclear Energy Systems”, prepared Jointly by the Proliferation Resistance and Physical Protection Working Group (PRPPWG) and the System Steering Committees and provisional System Steering Committees of the Generation IV International Forum, taking into account the evolution of both the systems, the GIF R&D activities, and an increased understanding of the PR&PP features. The white paper, prepared jointly by the GIF PRPPWG and the GIF GFR SSC, follows the high-level paradigm of the GIF PR&PP Evaluation Methodology to investigate the PR&PP features of the GIF GFR 2400 MWth reference design. The ALLEGRO reactor is also described. The EM2 and HEN MHR reactor are mentioned. An overview of fuel cycle for the GFR reference design and for the ALLEGRO reactor are provided. For PR, the document analyses and discusses the proliferation resistance aspects in terms of robustness against State-based threats associated with diversion of materials, misuse of facilities, breakout scenarios, and production in clandestine facilities. Similarly, for PP, the document discusses the robustness against theft of material and sabotage by non-State actors. The document follows a common template adopted by all the white papers in the updated series.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
NASA NTRS2010

Global Precipitation Measurement (GPM) Validation Network

The method averages the minimum TRMM PR and Ground Radar (GR) sample volumes needed to match-up spatially/temporally coincident PR and GR data types. PR and GR averages are calculated at the geometric intersection of the PR rays with the individual Ground Radar(GR)sweeps. Along-ray PR data are averaged only in the vertical, GR data are averaged only in the horizontal. Small difference in PR & GR reflectivity high in the atmosphere, relatively larger differences. Version 6 TRMM PR underestimates rainfall in the case of convective rain in the lower part of the atmosphere by 30 to 40 percent.

Schwaller, Mathew↗
NASA NTRSDate not supplied

Challenges, Considerations, and Opportunities for Exercise and Medical Accommodation Inside a Small Pressurized Rover

Pressurized Rovers (PR) can enable crew to explore away from a lander or surface habitat at distances not possible on foot or even in unpressurized rovers. Sustaining crew for multiple days, they can rove for weeks, independent of other surface elements. Because these are essentially mobile habitats, it is critical that they provide sufficient volume to accommodate the exercise and medical systems to maintain human health in remote, low gravity environments such as the Moon and Mars. This is an area of extensive unknowns as requirements have not yet been developed for exercise or medical systems in pressurized rovers. Yet they must be considered in vehicle sizing studies as they are significant volume drivers, requiring allocation for stowed and deployed hardware inside the rover cabin. Previously flown spacecraft have allocated varying amounts of volume based on the expected crew mission and the state of the art in these systems. NASA-STD-3001 provides high-level requirements for standards of medical care and exercise capabilities. Crew injuries are possible both inside the cabin and on extravehicular activities (EVA), therefore requiring medical capability. Exercise countermeasures are needed to counteract the debilitating effects of lowered gravity. This may include both reconditioning following a lengthy microgravity transit as well as ongoing countermeasures against the effect of low surface gravity. The NASA reference concept for the PR dates back to the Constellation Program and prototypes have been extensively tested in NASA’s Desert Research and Technology Studies (DRATS) program as well as at the NASA Johnson Space Center. The PR cabin is designed to accommodate two crewmembers and is subdivided into a forward cockpit area and a main body for crew habitation. EVAs are accomplished by transitioning through suit ports in the aft bulkhead into spacesuits. While no exercise devices have been developed for the PR, some have been prototyped and demonstrated in DRATS analog missions. A cycle ergometer performed reasonably well in DRATS testing as an aerobic exercise device and recent analysis work has theorized that a combination aerobic and resistive device could be packaged into a form factor similar to the DRATS ergometer. It is therefore suitable for use as an initial volumetric placeholder. No sensorimotor devices have been considered for the PR to aid in adaptation to surface gravity. However, there are commercially available treadmills that at minimum represent examples of the type of exercise system that could potentially be used for such a purpose. A combination of field test data, analysis, and CAD modeling will be used to perform a first pass assessment of whether these exercise devices can be stowed and deployed within the PR. Medical inventories from the International Space Station will be used as a volume placeholder for the PR medical system. A configuration will be discussed for medical deployment, including positioning of caregiver, patient, and medical equipment / supplies.

Pressurized Rover↗
DOE OSTI2020

Materials Data on PrAl5Ni2 by Materials Project

PrNi2Al5 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. Pr is bonded in a 12-coordinate geometry to four equivalent Ni and fourteen Al atoms. All Pr–Ni bond lengths are 3.22 Å. There are a spread of Pr–Al bond distances ranging from 3.33–3.55 Å. Ni is bonded in a 9-coordinate geometry to two equivalent Pr and seven Al atoms. There are a spread of Ni–Al bond distances ranging from 2.29–2.52 Å. There are two inequivalent Al sites. In the first Al site, Al is bonded in a linear geometry to two equivalent Pr and two equivalent Ni atoms. In the second Al site, Al is bonded in a distorted trigonal non-coplanar geometry to three equivalent Pr and three equivalent Ni atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pr3Ga by Materials Project

Pr3Ga is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Pr is bonded to eight equivalent Pr and four equivalent Ga atoms to form distorted PrPr8Ga4 cuboctahedra that share corners with twelve equivalent PrPr8Ga4 cuboctahedra, edges with eight equivalent GaPr12 cuboctahedra, edges with sixteen equivalent PrPr8Ga4 cuboctahedra, faces with four equivalent GaPr12 cuboctahedra, and faces with fourteen equivalent PrPr8Ga4 cuboctahedra. All Pr–Pr bond lengths are 3.47 Å. All Pr–Ga bond lengths are 3.47 Å. Ga is bonded to twelve equivalent Pr atoms to form GaPr12 cuboctahedra that share corners with twelve equivalent GaPr12 cuboctahedra, edges with twenty-four equivalent PrPr8Ga4 cuboctahedra, faces with six equivalent GaPr12 cuboctahedra, and faces with twelve equivalent PrPr8Ga4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pr2(Zn2Ge)3 by Materials Project

Pr2(Zn2Ge)3 crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Pr is bonded in a 6-coordinate geometry to nine Zn and six equivalent Ge atoms. There are three shorter (3.27 Å) and six longer (3.45 Å) Pr–Zn bond lengths. All Pr–Ge bond lengths are 3.17 Å. There are two inequivalent Zn sites. In the first Zn site, Zn is bonded in a 3-coordinate geometry to four equivalent Pr and three equivalent Ge atoms. There are one shorter (2.54 Å) and two longer (2.65 Å) Zn–Ge bond lengths. In the second Zn site, Zn is bonded in a 2-coordinate geometry to two equivalent Pr and two equivalent Ge atoms. Both Zn–Ge bond lengths are 2.54 Å. Ge is bonded in a 9-coordinate geometry to four equivalent Pr and five Zn atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PrAl2 by Materials Project

PrAl2 is Cubic Laves structured and crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Pr is bonded in a 12-coordinate geometry to four equivalent Pr and twelve equivalent Al atoms. All Pr–Pr bond lengths are 3.50 Å. All Pr–Al bond lengths are 3.35 Å. Al is bonded to six equivalent Pr and six equivalent Al atoms to form a mixture of corner, edge, and face-sharing AlPr6Al6 cuboctahedra. All Al–Al bond lengths are 2.86 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PrSnRh by Materials Project

PrRhSn crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Pr is bonded in a 11-coordinate geometry to five Rh and six equivalent Sn atoms. There are four shorter (3.09 Å) and one longer (3.11 Å) Pr–Rh bond lengths. There are two shorter (3.30 Å) and four longer (3.43 Å) Pr–Sn bond lengths. There are two inequivalent Rh sites. In the first Rh site, Rh is bonded in a 9-coordinate geometry to three equivalent Pr and six equivalent Sn atoms. All Rh–Sn bond lengths are 2.82 Å. In the second Rh site, Rh is bonded in a 9-coordinate geometry to six equivalent Pr and three equivalent Sn atoms. All Rh–Sn bond lengths are 2.88 Å. Sn is bonded in a 12-coordinate geometry to six equivalent Pr and four Rh atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PrZnNi by Materials Project

PrNiZn crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Pr is bonded in a 11-coordinate geometry to five Ni and six equivalent Zn atoms. There are four shorter (2.92 Å) and one longer (2.99 Å) Pr–Ni bond lengths. There are two shorter (3.22 Å) and four longer (3.24 Å) Pr–Zn bond lengths. There are two inequivalent Ni sites. In the first Ni site, Ni is bonded in a 9-coordinate geometry to three equivalent Pr and six equivalent Zn atoms. All Ni–Zn bond lengths are 2.58 Å. In the second Ni site, Ni is bonded in a 9-coordinate geometry to six equivalent Pr and three equivalent Zn atoms. All Ni–Zn bond lengths are 2.84 Å. Zn is bonded in a 12-coordinate geometry to six equivalent Pr, four Ni, and two equivalent Zn atoms. Both Zn–Zn bond lengths are 2.92 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PrZnPd by Materials Project

PrPdZn crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Pr is bonded in a 11-coordinate geometry to five Pd and six equivalent Zn atoms. There are four shorter (3.03 Å) and one longer (3.06 Å) Pr–Pd bond lengths. There are two shorter (3.30 Å) and four longer (3.34 Å) Pr–Zn bond lengths. There are two inequivalent Pd sites. In the first Pd site, Pd is bonded in a 9-coordinate geometry to three equivalent Pr and six equivalent Zn atoms. All Pd–Zn bond lengths are 2.71 Å. In the second Pd site, Pd is bonded in a 9-coordinate geometry to six equivalent Pr and three equivalent Zn atoms. All Pd–Zn bond lengths are 2.90 Å. Zn is bonded in a 4-coordinate geometry to six equivalent Pr and four Pd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PrGe3Rh by Materials Project

PrRhGe3 crystallizes in the tetragonal I4mm space group. The structure is three-dimensional. Pr is bonded in a 12-coordinate geometry to five equivalent Rh and twelve Ge atoms. There are one shorter (3.46 Å) and four longer (3.54 Å) Pr–Rh bond lengths. There are a spread of Pr–Ge bond distances ranging from 3.23–3.48 Å. Rh is bonded in a 5-coordinate geometry to five equivalent Pr and five Ge atoms. There are one shorter (2.41 Å) and four longer (2.46 Å) Rh–Ge bond lengths. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 2-coordinate geometry to four equivalent Pr, two equivalent Rh, and two equivalent Ge atoms. Both Ge–Ge bond lengths are 2.75 Å. In the second Ge site, Ge is bonded in a 1-coordinate geometry to four equivalent Pr, one Rh, and four equivalent Ge atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PrCoGe3 by Materials Project

PrCoGe3 crystallizes in the tetragonal I4mm space group. The structure is three-dimensional. Pr is bonded in a 12-coordinate geometry to five equivalent Co and twelve Ge atoms. There are one shorter (3.32 Å) and four longer (3.49 Å) Pr–Co bond lengths. There are a spread of Pr–Ge bond distances ranging from 3.14–3.36 Å. Co is bonded in a 5-coordinate geometry to five equivalent Pr and five Ge atoms. There are one shorter (2.30 Å) and four longer (2.36 Å) Co–Ge bond lengths. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 2-coordinate geometry to four equivalent Pr, two equivalent Co, and two equivalent Ge atoms. Both Ge–Ge bond lengths are 2.79 Å. In the second Ge site, Ge is bonded in a 1-coordinate geometry to four equivalent Pr, one Co, and four equivalent Ge atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pr3In by Materials Project

Pr3In is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Pr is bonded to eight equivalent Pr and four equivalent In atoms to form distorted PrPr8In4 cuboctahedra that share corners with twelve equivalent PrPr8In4 cuboctahedra, edges with eight equivalent InPr12 cuboctahedra, edges with sixteen equivalent PrPr8In4 cuboctahedra, faces with four equivalent InPr12 cuboctahedra, and faces with fourteen equivalent PrPr8In4 cuboctahedra. All Pr–Pr bond lengths are 3.56 Å. All Pr–In bond lengths are 3.56 Å. In is bonded to twelve equivalent Pr atoms to form InPr12 cuboctahedra that share corners with twelve equivalent InPr12 cuboctahedra, edges with twenty-four equivalent PrPr8In4 cuboctahedra, faces with six equivalent InPr12 cuboctahedra, and faces with twelve equivalent PrPr8In4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PrInRh by Materials Project

PrRhIn crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Pr is bonded in a 11-coordinate geometry to five Rh and six equivalent In atoms. There are four shorter (3.09 Å) and one longer (3.15 Å) Pr–Rh bond lengths. There are two shorter (3.31 Å) and four longer (3.43 Å) Pr–In bond lengths. There are two inequivalent Rh sites. In the first Rh site, Rh is bonded in a 9-coordinate geometry to six equivalent Pr and three equivalent In atoms. All Rh–In bond lengths are 2.93 Å. In the second Rh site, Rh is bonded in a 9-coordinate geometry to three equivalent Pr and six equivalent In atoms. All Rh–In bond lengths are 2.80 Å. In is bonded in a 4-coordinate geometry to six equivalent Pr and four Rh atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PrSnPt by Materials Project

PrPtSn crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Pr is bonded in a 11-coordinate geometry to five Pt and six equivalent Sn atoms. There are four shorter (3.12 Å) and one longer (3.15 Å) Pr–Pt bond lengths. There are two shorter (3.32 Å) and four longer (3.46 Å) Pr–Sn bond lengths. There are two inequivalent Pt sites. In the first Pt site, Pt is bonded in a 9-coordinate geometry to six equivalent Pr and three equivalent Sn atoms. All Pt–Sn bond lengths are 2.92 Å. In the second Pt site, Pt is bonded in a 9-coordinate geometry to three equivalent Pr and six equivalent Sn atoms. All Pt–Sn bond lengths are 2.85 Å. Sn is bonded in a 10-coordinate geometry to six equivalent Pr and four Pt atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pr3Al by Materials Project

Pr3Al is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Pr is bonded to eight equivalent Pr and four equivalent Al atoms to form distorted PrPr8Al4 cuboctahedra that share corners with twelve equivalent PrPr8Al4 cuboctahedra, edges with eight equivalent AlPr12 cuboctahedra, edges with sixteen equivalent PrPr8Al4 cuboctahedra, faces with four equivalent AlPr12 cuboctahedra, and faces with fourteen equivalent PrPr8Al4 cuboctahedra. All Pr–Pr bond lengths are 3.49 Å. All Pr–Al bond lengths are 3.49 Å. Al is bonded to twelve equivalent Pr atoms to form AlPr12 cuboctahedra that share corners with twelve equivalent AlPr12 cuboctahedra, edges with twenty-four equivalent PrPr8Al4 cuboctahedra, faces with six equivalent AlPr12 cuboctahedra, and faces with twelve equivalent PrPr8Al4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PrSnPd by Materials Project

PrPdSn crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Pr is bonded in a 11-coordinate geometry to five Pd and six equivalent Sn atoms. There are four shorter (3.12 Å) and one longer (3.17 Å) Pr–Pd bond lengths. There are two shorter (3.33 Å) and four longer (3.46 Å) Pr–Sn bond lengths. There are two inequivalent Pd sites. In the first Pd site, Pd is bonded in a 9-coordinate geometry to six equivalent Pr and three equivalent Sn atoms. All Pd–Sn bond lengths are 2.94 Å. In the second Pd site, Pd is bonded in a 9-coordinate geometry to three equivalent Pr and six equivalent Sn atoms. All Pd–Sn bond lengths are 2.84 Å. Sn is bonded in a 10-coordinate geometry to six equivalent Pr and four Pd atoms.

36 MATERIALS SCIENCE↗