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At least 127 records · Page 7

All sources NASA NTRS DOE OSTI

DOE OSTI2024

Partition between supercooled liquid droplets and ice crystals in mixed-phase clouds based on airborne in situ observations

Abstract. The onset of ice nucleation in mixed-phase clouds determines the lifetime and microphysical properties of ice clouds. In this work, we develop a novel method that differentiates between various phases of mixed-phase clouds, such as clouds dominated by pure liquid or pure ice segments, compared with those having ice crystals surrounded by supercooled liquid water droplets or vice versa. Using this method, we examine the relationship between the macrophysical and microphysical properties of Southern Ocean mixed-phase clouds at −40 to 0 °C (e.g. stratiform and cumuliform clouds) based on the in situ aircraft-based observations during the US National Science Foundation Southern Ocean Clouds, Radiation, Aerosol Transport Experimental Study (SOCRATES) flight campaign. The results show that the exchange between supercooled liquid water and ice crystals from a macrophysical perspective, represented by the increasing spatial ratio of regions containing ice crystals relative to the total in-cloud region (defined as ice spatial ratio), is positively correlated with the phase exchange from a microphysical perspective, represented by the increasing ice water content (IWC), decreasing liquid water content (LWC), increasing ice mass fraction, and increasing ice particle number fraction (IPNF). The mass exchange between liquid and ice becomes more significant during phase 3 when pure ice cloud regions (ICRs) start to appear. Occurrence frequencies of cloud thermodynamic phases show a significant phase change from liquid to ice at a similar temperature (i.e. −17.5 °C) among three types of definitions of mixed-phase clouds based on ice spatial ratio, ice mass fraction, or IPNF. Aerosol indirect effects are quantified for different phases using number concentrations of aerosols greater than 100 or 500 nm (N>100 and N>500, respectively). N>500 shows stronger positive correlations with ice spatial ratios compared with N>100. This result indicates that larger aerosols potentially contain ice-nucleating particles (INPs), which facilitate the formation of ice crystals in mixed-phase clouds. The impact of N>500 is also more significant in phase 2 when ice crystals just start to appear in the mixed phase compared with phase 3 when pure ICRs have formed, possibly due to the competing aerosol indirect effects on primary and secondary ice production in phase 3. The thermodynamic and dynamic conditions are quantified for each phase. The results show stronger in-cloud turbulence and higher updraughts in phases 2 and 3 when liquid and ice coexist compared with pure liquid or ice (phases 1 and 4, respectively). The highest updraughts and turbulence are seen in phase 3 when supercooled liquid droplets are surrounded by ice crystals. These results indicate both updraughts and turbulence support the maintenance of supercooled liquid water amongst ice crystals. Overall, these results illustrate the varying effects of aerosols, thermodynamics, and dynamics through various stages of mixed-phase cloud evolution based on this new method that categorizes cloud phases.

54 ENVIRONMENTAL SCIENCES↗

NASA NTRS1981

HCMM hydrological analysis in Utah

Progress in analysis of Heat Capacity Mapping Mission (HCMM) infrared and visible observations of the hydrology of Utah Lake is reported. Correlation between HCMM intensities converted to temperature and ground truth temperatures was investigated, and a conversion offset value determined. Ground truth surface temperatures minus HCMM temperatures were plotted against several hydrological parameters. Relationships among visible data, thermal data, and algae concentrations were considered, and summer concentrations of predominant algae species determined. Investigations on the effects of varying algae concentrations on evaporation rates are reported. Efforts to develop a model for evaporation estimation are reported. The relationship between air and water surface temperatures was studied and the temperature distribution in different segments of the lake investigated. Indications of the existence of thermal springs are reported. Correlation of HCMM surface temperature data and depth to groundwater were investigated.

Source record↗

DOE OSTI2024

Commercial Building Stock Segmentation for Decarbonization Planning

This document discusses the development of a segmentation approach for the U.S. commercial building stock that is focused on identifying similarities that align with common decarbonization strategies. The resulting nine-segment approach primarily uses similarities in heating, ventilation, and air conditioning (HVAC) systems, service water heating systems, and presence of cooking equipment to separate buildings into categories.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2020

One-Step Ahead Prediction of Thermal Mixing Tee Sensors with Long Short Term Memory (LSTM) Neural Networks

High-temperature advanced reactors under development, such as sodium fast reactors (SFR) and molten salt cooled reactors (MSCR), are expected to offer lower levelized cost of energy (LCOE) compared to existing light water reactor (LWR’s). In the existing light water reactors (LWR’s), operation and maintenance (O&M) expenses constitute the largest fraction of the total operating cost. Some of the O&M costs are related maintenance of sensors which can fail due to exposure to harsh environment in a reactor. The O&M costs of Advanced Reactor (AR)’s are expected to constitute a significant fraction of the total cost as well, because of high temperature and radiation level in AR are likely to cause material fatigue and premature failure of sensors and components. The O&M costs in AR’s could be reduced through integration of advanced informatics of performance-related sensors into a digital twin designed for reactor monitoring. For example, machine learning (ML) could be employed for real-time validation and correction of performance-related sensors, and reducing the number of performance-related physical sensor units through virtual sensing. As part of the effort, we investigate real-time validation of thermal hydraulic sensors through one-step ahead forecasting of sensor values using long short-term memory (LSTM) recurrent neural networks (RNN). The sensors are installed in a flow loop containing a thermal mixing tee, which is a common experimental model to study thermal fatigue in a thermal hydraulic loop. In addition, nonlinear transients generated in a thermal mixing tee constitute a good challenge data set for training and validation of ML algorithms. Sensors in this study include thermocouples, flow meters, and optical fibers for distributed temperature sensing. In one experiment, measurement data sets were obtained for a loop was filled with water, and in another experiment, measurements were performed on a loop filled with liquid metal Galinstan. We have also conducted preliminary investigation of one-step ahead prediction of fiber optics-based distributed temperature sensing with LSTM networks. In predicting fiber-based temperature measurements, we treated each gauge pitch of the fiber as an independent sensor. Accuracy of one-step ahead forecasting was estimated by calculating root mean square error (RMSE) for the test segment of time series of each sensor. RMSE’s for temperature sensors in water loop were, for the most part, lower than for the same sensors in Galinstan loop. The RMSE’s for flow meters were similar for both loops. The RMSE’s for distributed temperature measured with the fiber optic sensor were similar to those of the point sensors. Results of this study demonstrated the capability of LSTM one-step ahead forecasting with RMSE comparable to uncertainty in sensor measurements.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

NASA NTRS1959

Water-Landing Characteristics of a Reentry Capsule

Experimental and theoretical investigations have been made to determine the water-landing characteristics of a conical-shaped reentry capsule having a segment of a sphere as the bottom. For the experimental portion of the investigation, a 1/12-scale model capsule and a full-scale capsule were tested for nominal flight paths of 65 deg and 90 deg (vertical), a range of contact attitudes from -30 deg to 30 deg, and a full-scale vertical velocity of 30 feet per second at contact. Accelerations were measured by accelerometers installed at the centers of gravity of the model and full-scale capsules. For the model test the accelerations were measured along the X-axis (roll) and Z-axis (yaw) and for the full-scale test they were measured along the X-axis (roll), Y-axis (pitch), and Z-axis (yaw). Motions and displacements of the capsules that occurred after contact were determined from high-speed motion pictures. The theoretical investigation was conducted to determine the accelerations that might occur along the X-axis when the capsule contacted the water from a 90 deg flight path at a 0 deg attitude. Assuming a rigid body, computations were made from equations obtained by utilizing the principle of the conservation of momentum. The agreement among data obtained from the model test, the full-scale test, and the theory was very good. The accelerations along the X-axis, for a vertical flight path and 0 deg attitude, were in the order of 40g. For a 65 deg flight path and 0 deg attitude, the accelerations along the X-axis were in the order of 50g. Changes in contact attitude, in either the positive or negative direction from 0 deg attitude, considerably reduced the magnitude of the accelerations measured along the X-axis. Accelerations measured along the Y- and Z-axes were relatively small at all test conditions.

John R McGehee↗

NASA NTRS1958

Water Landing Characteristics of a Reentry Capsule

John R McGehee↗

DOE OSTI2022

Development and Standup Testing of a System to Observe Fission Gas Release During Transient Heating of Nuclear Fuel Element Segments

As part of an effort to increase the burnup of nuclear fuels used in Light Water Reactors, the mechanisms and timing of fission gas release during high temperature transients must be studied. In this work, a system was built to observe fission gas release of fuel element sections under evacuated conditions, at temperatures up to 800 °C. System capabilities and limitations are overviewed in this report. The system was further tested with a hydrogen-infused titanium foils and gas release was observed in agreement with literature observations. Pressure was monitored with two sensors, and temperature was monitored using a thermocouple and a pyrometer with continuous visual imaging.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

NASA NTRS1993

Hazard calculations of diffuse reflected laser radiation for the SELENE program

The hazards from diffuse laser light reflections off water clouds, ice clouds, and fog and from possible specular reflections off ice clouds were assessed with the American National Standards (ANSI Z136.1-1986) for the free-electron-laser parameters under consideration for the Segmented Efficient Laser Emission for Non-Nuclear Electricity (SELENE) Program. Diffuse laser reflection hazards exist for water cloud surfaces less than 722 m in altitude and ice cloud surfaces less than 850 m in altitude. Specular reflections from ice crystals in cirrus clouds are not probable; however, any specular reflection is a hazard to ground observers. The hazard to the laser operators and any ground observers during heavy fog conditions is of such significant magnitude that the laser should not be operated in fog.

Miner, Gilda A.↗

NASA NTRS1973

Movable-molybdenum-reflector reactivity experiments for control studies of compact space power reactor concepts

An experimental reflector reactivity study was made with a compact cylindrical reactor using a uranyl fluoride - water fuel solution. The reactor was axially unreflected and radially reflected with segments of molybdenum. The reflector segments were displaced incrementally in both the axial and radial dimensions, and the shutdown of each configuration was measured by using the pulsed-neutron source technique. The reactivity effects for axial and radial displacement of reflector segments are tabulated separately and compared. The experiments provide data for control-system studies of compact-space-power-reactor concepts.

Fox, T. A.↗

NASA NTRS1976

LANDSAT follow-on: A report by the applications survey groups. Volume 1: Executive summary

Attempts at operational usage of the LANDSAT imagery by non NASA users are studied with particular emphasis on profitable use of the imagery, as contrasted with investigations concerned with research and development of a technology. An evaluation is given of the functional capabilities of the LANDSAT follow-on and ground systems designs in terms of user requirements and desiderata for data measurements, products, and parameters. Applications survey groups (ASGs) were formed for mineral and petroleum exploration, inland water resources, land inventory, and agriculture. The members were drawn from all segments of the user community: Federal agencies, state and local governments or agencies (or from associations of such constituencies), industry and universities. They were selected so that in aggregate they would be able to adequately assess the state-of-the-art in their technical areas and represent this in the ASG deliberations.

Billingsley, F. C.↗

NASA NTRS1978

Large Area Crop Inventory Experiment (LACIE). Detecting and monitoring agricultural vegetative water stress over large areas using LANDSAT digital data

The author has identified the following significant results. The Green Number Index technique which uses LANDSAT digital data from 5X6 nautical mile sampling frames was expanded to evaluate its usefulness in detecting and monitoring vegetative water stress over the Great Plains. At known growth stages for wheat, segments were classified as drought or non drought. Good agreement was found between the 18 day remotely sensed data and a weekly ground-based crop moisture index. Operational monitoring of the 1977 U.S.S.R. and Australian wheat crops indicated drought conditions. Drought isoline maps produced by the Green Number Index technique were in good agreement with conventional sources.

Thompson, D. R.↗

NASA NTRS1983

NMR (Nuclear Magnetic Resonance) of solid biopolymers

It has been possible through the study of proton relaxation in solid proteins and related molecules to identify and characterize the following molecular motions which contribute to relaxation: (1) methyl group reorientation; (2) segmental motion; (3) side chain motion; (4) proline ring puckering; and (5) water molecule reorientation.

Andrew, E. R.↗

NASA NTRS2022

Parameterizing Single Scattering Properties Across the Electromagnetic Spectrum for Water Cloud Retrieval

Water clouds are composed of spherical water droplets, to which the Mie solution applies for their electromagnetic scattering. The essential variable of Mie solutions is ξ ≡ 𝑚𝑘𝐷 (or equivalently 𝑚𝑘𝑟), where 𝑚 is the complex index of refraction of water, 𝑘 = 2π/λ the angular wavenumber, λ the wavelength, and 𝐷 (𝑟) the diameter (radius) of the water droplet. Consequently, all water-droplet single-scattering properties, such as extinction and scattering efficiencies, i.e., 𝑄 and , are functions of , 𝑒 𝑄𝑠 ξ which provides a convenient pathway to parameterize water-droplet single-scattering properties across the electromagnetic spectrum or spectrum segments. In this paper, we first demonstrate that the numerical Mie solution indeed depends only on ξ. We then present our first attempt to parameterize extinction efficiency across the visible-infrared spectrum.

Kwo-Sen Kuo↗

DOE OSTI2021

High-performance multiblock PEMs containing a highly acidic fluorinated-hydrophilic domain for water electrolysis

The present paper describes the design and evaluation of novel hydrophilic–hydrophobic poly(arylene ether sulfone) (PAES) multiblock copolymers for their synergistic effects upon transport properties and their potential use in proton exchange membrane water electrolysis. The multiblock copolymers are prepared via a coupling reaction between (i) a hydrophilic segment consisting of a disulfonated quinone fluorinated biphenyl group that contains fluorine moieties next to the sulfonated groups to increase the acidity, and (ii) hydrophobic segments composed of non-sulfonated biphenyl sulfone to provide dimensional stability. Two different lengths (molecular weights; 5k and 10k, where k represents 10 3 g mol -1 ) of hydrophobic segments are used to investigate the effects of the membrane properties compared with those of Nafion® and PAES random copolymer (i.e., BPSH40). Atomic force microscopy images of the BPSH40 and multiblock membranes are shown to agree closely with a mesoscale simulation, thus confirming the importance of the morphological effect upon the transport properties. Furthermore, the multiblock copolymer with a higher proportion of hydrophilic segments (10 k–5k) was shown to provide enhanced performance (3.41 A cm -2 at 1.9 V) compared to the multiblock copolymer with equal proportions of hydrophilic and hydrophobic segments (10 k–10 k) due to the greater continuity of nano-sized ionic channels.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

NASA NTRS1993

A Unique Photon Bombardment System for Space Applications

The innovative Electromagnetic Radiation Collection and Concentration System (EMRCCS) described is the foundation for the development of a multiplicity of space and terrestrial system formats. The system capability allows its use in the visual, infrared, and ultraviolet ranges of the spectrum for EM collection, concentration, source/receptor tracking, and targeting. The nonimaging modular optical system uses a physically static position aperture for EM radiation collection. Folded optics provide the concentration of the radiation and source autotracking. The collected and concentrated electromagnetic radiation is utilized in many applications, e.g., solar spectrum in thermal and associative photon bombardment applications for hazardous waste management, water purification, metal hardening, hydrogen generation, photovoltaics, etc., in both space and terrestrial segment utilization. Additionally, at the high end of the concentration capability range, i.e., 60,000+, a solar-pulsed laser system is possible.

Klein, E. J.↗

NASA NTRS1997

Residual Stress Measurements After Proof and Flight: ETP-0403

The intent of this testing was to evaluate the residual stresses that occur in and around the attachment details of a case stiffener segment that has been subjected to flight/recovery followed by proof loading. Not measured in this test were stresses relieved at joint disassembly due to out-of-round and interference effects, and those released by cutting the specimens out of the case segment. The test article was lightweight case stiffener segment 1U50715, S/N L023 which was flown in the forward stiffener position on flight SRM 14A and in the aft position on flight SRM24A. Both of these flights were flown with the 3 stiffener ring configuration. Stiffener L023 had a stiffener ring installed only on the aft stub in its first flight, and it had both rings installed on its second flight. No significant post flight damage was found on either flight. Finally, the segment was used on the DM-8 static test motor in the forward position. No stiffener rings were installed. It had only one proof pressurization prior to assignment to its first use, and it was cleaned and proof tested after each flight. Thus, the segment had seen 3 proof tests, two flight pressurizations, and two low intensity water impacts prior to manufacturing for use on DM-8. On DM-8 it received one static firing pressurization in the horizontal configuration. Residual stresses at the surface and in depth were evaluated by both the x-ray diffraction and neutron beam diffraction methods. The x-ray diffraction evaluations were conducted by Technology for Energy Corporation (TEC) at their facilities in Knoxville, TN. The neutron beam evaluations were done by Atomic Energy of Canada Limited (AECL) at the Chalk River Nuclear Laboratories in Ontario. The results showed general agreement with relatively high compressive residual stresses on the surface and moderate to low subsurface tensile residual stresses.

Webster, Ronald L..↗

NASA NTRS2003

STS-107 Mission Highlights Resource, Part 4 of 4

This video, Part 4 of 4, shows the activities of the STS-107 crew during flight days 13 through 15 of the Columbia orbiter's final flight. The crew consists of Commander Rick Husband, Pilot William McCool, Payload Commander Michael Anderson, Mission Specialists David Brown, Kalpana Chawla, and Laurel Clark, and Payload Specialist Ilan Ramon. The highlight of flight day 13 is Kalpana Chawla conversing with Mission Control Center in Houston during troubleshooting of the Combustion Module in a recovery procedure to get the MIST fire suppression experiment back online. Chawla is shown replacing an atomizer head. At Mission Control Center a vase of flowers commemorating the astronauts who died on board Space Shuttle Challenger's final flight is shown and explained. The footage of flight day 14 consists of a tour of Columbia's flight deck, middeck, and Spacehab research module. Rick Husband narrates the tour, which features Kalpana Chawla, Laurel Clark, and himself. The astronauts demonstrate hygene, a dining tray, the orbiter's toilet, and a space iron, which is a rack for strapping down shirts. The Earth limb is shown with the Spacehab module in the foreground. Clark exercises on a bicycle for a respiration experiment, and demonstrates how a compact disk player gyrates in microgravity. On flight day 15, the combustion module is running again, and footage is shown of the Water Mist Fire-Suppression Experiment (Mist) in operation. Laurel Clark narrates a segment of the video in which Ilan Ramon exercises on a bicycle, Rick Husband, Kalpana Chawla, and Ramon demonstrate spinning and push-ups in the Spacehab module, and Clark demonstrates eating from a couple of food packets. The video ends with a shot of the Earth limb reflected on the radiator on the inside of Columbia's open payload bay door with the Earth in the background.

Source record↗

DOE OSTI2024

FUEL PERFORMANCE STUDIES AT IDAHO NATIONAL LABORATORY MAKING USE OF THE BYRON FUEL SHIPMENT

In December of 2023 a shipment of commercially irradiated fuel rods from the Byron Generating Station in Illinois was successfully shipped to the Materials and Fuels Complex (MFC) at Idaho National Laboratory (INL). The make-up of the rods includes a mix of cladding types from traditional ZirloTM, advanced zirconium alloys, and chrome coated ZirloTM. Burnups range from regular end of life values to over 70 GWd/MTU rod average. The R&D plan for the rods involves multiple projects from developing licensing data for new claddings to integral transient tests to support burnup extension efforts in the United States. The R&D began in early 2024 with the nondestructive examinations of the rods after which they will be sectioned for microscopy, mechanical testing, and analytical chemistry. Additionally, many rod segments will be refabricated into new test pins and inserted into a static water capsule for integral Reactivity Initiated Accident (RIA) and Loss of Coolant Accident (LOCA) testing at the TREAT reactor.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗