Recondensation from a particle-vapor source flow into vacuum.
Water vapor recondensation effect on structure of liquid particle flow into vacuum
Glenn, L. A.↗
SEARCH · Engineering Papers
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Third Earth Resources Technology Satellite Symposium. Volume 3: Discipline summary reports
Presentations at the conference covered the following disciplines: (1) agriculture, forestry, and range resources; (2) land use and mapping; (3) mineral resources, geological structure, and landform surveys; (4) water resources; (5) marine resources; (6) environment surveys; and (7) interpretation techniques.
Freden, S. C.↗
Review of Nimbus-5 Microwave Spectrometer results
Nimbus-E Microwave Spectrometer (NEMS) data are analyzed, especially those obtained from the 53.65, 54.9, and 58.8 GHz channels, corresponding to sensing at 4, 11, and 18 km respectively. The observations permit highly precise horizontal temperature profiles to be established and are hardly affected by clouds. The sensings of the 54.9 GHz channel unambiguously delineate wave structure on the equator. Horizontal water vapor profiles are derived from the 22.235 and 31.4 GHz channel data.
Staelin, D. H.↗
A statistical analysis of data extraction for land cover information from high-altitude and satellite images
Land cover information from a 10 by 30 km test site in eastern Wisconsin extracted using 70 mm positive LANDSAT transparencies in an additive color viewer at a scale of 1:500,000 was compared with land cover information extracted using LANDSAT 9 x 9 inch positive transparencies at a scale of 1:1,000,000. Color infrared photography (NASA RB-57) at a scale of 1:60,000 provided ground truth for each land cover type. Interpretations were made for four land cover classes: 1) forest-brushland; (2) structures-barren land; (3) surface water; and (4) agricultural-open land. Statistical comparisons showed that neither method for the extraction of this data was clearly superior.
Kiefer, R. W.↗
Technology of GaAs metal-oxide-semiconductor solar cells
The growth of an oxide interfacial layer was recently found to increase the open-circuit voltage (OCV) and efficiency by up to 60 per cent in GaAs metal-semiconductor solar cells. Details of oxidation techniques to provide the necessary oxide thickness and chemical structure and using ozone, water-vapor-saturated oxygen, or oxygen gas discharges are described, as well as apparent crystallographic orientation effects. Preliminary results of the oxide chemistry obtained from X-ray, photoelectron spectroscopy are given. Ratios of arsenic oxide to gallium oxide of unity or less seem to be preferable. Samples with the highest OVC predominantly have As(+3) in the arsenic oxide rather than As(+5). A major difficulty at this time is a reduction in OCV by 100-200 mV when the antireflection coating is vacuum deposited.
Stirn, R. J.↗
Winged cargo return vehicle. Volume 1: Conceptual design
The Advanced Design Project (ADP) allows an opportunity for students to work in conjunction with NASA and other aerospace companies on NASA Advanced Design Projects. The following volumes represent the design report: Volume 1 Conceptual Design; Volume 2 Wind Tunnel Tests; Volume 3 Structural Analysis; and Volume 4 Water Tunnel Tests. The project chosen by the University of Minnesota in conjunction with NASA Marshall Space Flight Center for this year is a Cargo Return Vehicle (CRV) to support the Space Station Freedom. The vehicle is the third generation of vehicles to be built by NASA, the first two being the Apollo program, and the Space Shuttle program. The CRV is to work in conjunction with a personnel launch system (PLS) to further subdivide and specialize the vehicles that NASA will operate in the year 2000. The cargo return vehicle will carry payload to and from the Space Station Freedom (SSF).
Source record↗
Summary Report of Mission Acceleration Measurement for STS-87: Launched November 19, 1997
Two accelerometer systems, the Orbital Acceleration Research Experiment and the Space Acceleration Measurement System, were used to measure and record the microgravity environment of the Orbiter Columbia during the STS-87 mission in November-December 1997. Data from two separate Space Acceleration Measurement System units were telemetered to the ground during the mission and data plots were displayed for investigators of the Fourth United States Microgravity Payload experiments in near real-time using the World Wide Web. Plots generated using Orbital Acceleration Research Experiment data (telemetered to the ground using a tape delay) were provided to the investigators using the World Wide Web approximately twelve hours after data recording. Disturbances in the microgravity environment as recorded by these instruments are grouped by source type: Orbiter systems, on-board activities, payload operations, and unknown sources. The environment related to the Ku-band antenna dither, Orbiter structural modes, attitude deadband collapses, water dump operations, crew sleep, and crew exercise was comparable to the effects of these sources on previous Orbiter missions. Disturbances related to operations of the Isothermal Dendritic Growth Experiment and Space Acceleration Measurement Systems that were not observed on previous missions are detailed. The effects of Orbiter cabin and airlock depressurization and extravehicular activities are also reported for the first time. A set of data plots representing the entire mission is included in the CD-ROM version of this report.
Rogers, Melissa J. B.↗
STS-107 Crew Interviews: Kalpana Chawla MS2
STS-107 Mission Specialist 2 Kalpana Chawla is seen during this preflight interview where she gives a quick overview of the mission before answering questions about her inspiration to become an astronaut and her career path. Chawla outlines her role in the mission in general, and specifically in conducting the on-board science experiments. She discusses the following experiments in detail: MEIDEX (Mediterranean Israel Dust Experiment), CM2 (Combustion Module 2), MIST (Water Mist Fire Suppression), SOFBALL (Structures of Flame Balls at Low Lewis-Number), LSP (Laminar Soot Processes), MGM (Mechanics of Granular Materials) and BDS (Biotechnology Demonstration System). She also discusses the potential benefits of space research, the dual-work shift of the mission and the rewards of international cooperation.
Source record↗
Summary Report of Mission Acceleration Measurement for STS-87, Launched November 19, 1997
Two accelerometer systems, the Orbital Acceleration Research Experiment and the Space Acceleration Measurement System, were used to measure and record the microgravity environment of the Orbiter Columbia during the STS-87 mission in November-December 1997. Data from two separate Space Acceleration Measurement System units were telemetered to the ground during the mission and data plots were displayed for investigators of the Fourth United States Microgravity Payload experiments in near real-time using the World Wide Web. Plots generated using Orbital Acceleration Research Experiment data (telemetered to the ground using a tape delay) were provided to the investigators using the World Wide Web approximately twelve hours after data recording. Disturbances in the microgravity environment as recorded by these instruments are grouped by source type: Orbiter systems, on-board activities, payload operations, and unknown sources. The environment related to the Ku-band antenna dither, Orbiter structural modes, attitude deadband collapses, water dump operations, crew sleep, and crew exercise was comparable to the effects of these sources on previous Orbiter missions. Disturbances related to operations of the Isothermal Dendritic Growth Experiment and Space Acceleration Measurement Systems that were not observed on previous missions are detailed. The effects of Orbiter cabin and airlock depressurization and extravehicular activities are also reported for the first time. A set of data plots representing the entire mission is included in the CD-ROM version of this report.
Rogers, Melissa J. B.↗
INL High-Performance and Sustainable Building Strategy
High-performance buildings are reliable, cost effective, and sustainable structures that minimize energy and water use, reduce solid waste and pollutant emissions, and limit the depletion of natural resources. High-performance buildings also provide a thermally and visually comfortable working environment that increases productivity for building occupants. As Idaho National Laboratory (INL) is the nation’s premier nuclear energy research laboratory, the physical infrastructure requires continual updating and repurposing to help accomplish that mission. INL’s infrastructure must incorporate high-performance sustainable design features to be fiscally responsible and reflect an image of innovation to the public and prospective employees. INL is a large consumer of energy with annual energy costs exceeding $16M. This High-Performance and Sustainable Building Strategy will help engineering and construction project teams design sustainable facilities, reduce life cycle operating costs, and support the INL net-zero plan while providing INL employees with a safe and healthy working environment. With these goals in mind, the recommendations described in this document are intended to form INL’s foundation for sustainable and high-performance building standards. This strategy incorporates the latest federal and Department of Energy (DOE) orders and directives, including DOE Order 436.1A, “Departmental Sustainability,” the DOE Sustainability Plan (SP), the INL Site Sustainability Plan (SSP), and Code of Federal Regulations (CFR). This document identifies the requirements of the “Guiding Principles for Sustainable Federal Buildings” (Guiding Principles) and briefly highlights the Leadership in Energy and Environmental Design (LEED) Gold certification. LEED Gold certification can be used to meet many of the requirements of the Guiding Principles.
29 ENERGY PLANNING, POLICY, AND ECONOMY↗
Using High Frequency Passive Microwave, A-train, and TRMM Data to Evaluate Hydrometer Structure in the NASA GEOS-5 Data Assimilation System
Validating water vapor and prognostic condensate in global models remains a challenging research task. Model parameterizations are still subject to a large number of tunable parameters; furthermore, accurate and representative in situ observations are very sparse, and satellite observations historically have significant quantitative uncertainties. Progress on improving cloud / hydrometeor fields in models stands to benefit greatly from the growing inventory ofA-Train data sets. ill the present study we are using a variety of complementary satellite retrievals of hydrometeors to examine condensate produced by the emerging NASA Modem Era Retrospective Analysis for Research and Applications, MERRA, and its associated atmospheric general circulation model GEOS5. Cloud and precipitation are generated by both grid-scale prognostic equations and by the Relaxed Arakawa-Schubert (RAS) diagnostic convective parameterization. The high frequency channels (89 to 183.3 GHz) from AMSU-B and MRS on NOAA polar orbiting satellites are being used to evaluate the climatology and variability of precipitating ice from tropical convective anvils. Vertical hydrometeor structure from the Tropical Rainfall Measuring Mission (TRMM) and CloudSat radars are used to develop statistics on vertical hydrometeor structure in order to better interpret the extensive high frequency passive microwave climatology. Cloud liquid and ice water path data retrieved from the Moderate Resolution Imaging Spectroradiometer, MODIS, are used to investigate relationships between upper level cloudiness and tropical deep convective anvils. Together these data are used to evaluate cloud / ice water path, gross aspects of vertical hydrometeor structure, and the relationship between cloud extent and surface precipitation that the MERRA reanalysis must capture.
Robertson, Franklin↗
Drivers of Water Use in the Agricultural Sector of the European Union 27
Population growth and the uncertain hazards that accompany climate change have put increasing pressure on the management and sustainability of water. It has a direct impact on agriculture and its domestic and international supply chain linkages. As one of the largest agricultural producers in the world, the European Union (EU) is particularly sensitive to changes in water availability. Therefore, here we perform a structural decomposition analysis based on the recently released EXIOBASE 3 database to examine in depth how changes in water input coefficients, in final demand and in technology have affected changes in water use across crops. Crop production consumes 99% of the direct water in agriculture. Our results show that the largest EU crop producers have experienced an increase in water use that is mostly driven by changes in technology. On the other hand, several Mediterranean countries, where water scarcity has been a problem for years, have decreased their water consumption mostly thanks to an improvement in their water intensity. Results by crop are consistent with those at the aggregated level except for vegetables of which water use changes have been primarily driven by changes in final demand and water intensity.
54 ENVIRONMENTAL SCIENCES↗
Water Model Tests for Semirigid Airships
The design of complicated structures often presents problems of extreme difficulty which are frequently insoluble. In many cases, however, the solution can be obtained by tests on suitable models. These model tests are becoming so important a part of the design of new engineering structures that their theory has become a necessary part of an engineer's knowledge. For balloons and airships water models are used. These are models about 1/30 the size of the airship hung upside down and filled with water under pressure. The theory shows that the stresses in such a model are the same as in the actual airship. In the design of the Army Semirigid Airship RS-1 no satisfactory way was found to calculate the stresses in the keel due to the changing shape of the bag. For this purpose a water model with a flexible keel was built and tested. This report gives the theory of the design, construction, and testing of such a water model.
Tuckerman, L.B.↗
Investigation of porous polydimethylsiloxane structures with tunable properties induced by the phase separation technique
This article reports the fabrication and characterization of porous polydimethylsiloxane (PDMS) structures developed by the solvent evaporationinduced phase separation technique. Here, ternary systems containing water/ tetrahydrofuran (THF)/PDMS with various concentrations are produced to form a stable solution. The porous PDMS structures are formed by removing the solvent (THF) and nonsolvent (water) phases during the stepping heat treatment procedure. The analytical ternary phase diagram is constructed based on the thermodynamic equilibrium state in the polymer solution to explain the stable/unstable formulations and the possible composition change path. The results show that the isolated pores with the adjustable pore size ranging from 330 to 1900 μm are obtained by tuning the water to the THF ratio. The mechanical properties of the porous PDMS structures are determined by conducting the tensile tests on the prepared dog bone-shaped specimens. A wide range of elastic modulus ranging between 0.49 and 1.05 MPa was achieved without affecting the density of the porous sample by adjusting the solvent and non-solvent content in the solution. It is shown that the flexibility of the porous structures can be improved by reducing the ratio of water to THF and decreasing the PDMS content. The porosity measurements reveal that the PDMS concentration is the major phase controlling the porosity of the structure, while the effect of water/THF is negligible.
42 ENGINEERING↗
Molecular dynamics simulation studies of 1,3-dimethyl imidazolium nitrate ionic liquid with water
The fundamental understanding of intermolecular interactions of ionic liquids (ILs) with water is essential in predicting IL–water thermodynamic properties. In this study, intermolecular or noncovalent interactions were studied for 1,3-dimethyl imidazolium [DMIM]+ cation and nitrate [NO 3 ] – anion with water, employing quantum mechanics and molecular dynamics simulations. Molecular dynamics simulations were performed using a revised multipolar polarizable force field. The effect of water on ionic liquids was evaluated in terms of thermodynamic and dynamic properties. Thermodynamic properties included liquid densities ρ, excess molar volumes ΔV E , and liquid structures g(r). Dynamic properties included self-diffusion coefficients D of mixture constituents as a function of water concentration. The density of ionic liquid–water mixtures monotonically decrease with increasing concentration of water. A negative excess volume was obtained for low and high water concentrations, demonstrating strong intermolecular interactions of water with ionic liquid components. Liquid structures of ionic liquid–water mixtures revealed a tendency for anions to interact with cations at shorter intermolecular distances when the water concentration is increased. Diffusion rates were found to increase for all mixture components with increase in the fraction of water. A significant change in the diffusion rate was found at ~0.3 weight fraction of water. However, the water self-diffusion coefficient was dominant at all concentrations. Furthermore, the ratio of water/anion and anion/cation self-diffusion coefficients was found to decrease linearly with increasing concentration of water molecules.
36 MATERIALS SCIENCE↗
Point-of-use filtration units as drinking water distribution system sentinels
Abstract Municipal drinking water distribution systems (DWDSs) and associated premise plumbing (PP) systems are vulnerable to proliferation of opportunistic pathogens, even when chemical disinfection residuals are present, thus presenting a public health risk. Monitoring the structure of microbial communities of drinking water is challenging because of limited continuous access to faucets, pipes, and storage tanks. We propose a scalable household sampling method, which uses spent activated carbon and reverse osmosis (RO) membrane point-of-use (POU) filters to evaluate mid- to long-term occurrence of microorganisms in PP systems that are relevant to consumer exposure. As a proof of concept, POU filter microbiomes were collected from four different locations and analyzed with 16S rRNA gene amplicon sequencing. The analyses revealed distinct microbial communities, with occasional detection of potential pathogens. The findings highlight the importance of local, and if possible, continuous monitoring within and across distribution systems. The continuous operation of POU filters offers an advantage in capturing species that may be missed by instantaneous sampling methods. We suggest that water utilities, public institutions, and regulatory agencies take advantage of end-of-life POU filters for microbial monitoring. This approach can be easily implemented to ensure drinking water safety, especially from microbes of emerging concerns; e.g., pathogenic Legionella and Mycobacterium species.
42 ENGINEERING↗
Isotope effects in dynamics of water isotopologues induced by core ionization at an x-ray free-electron laser
Dynamical response of water exposed to x-rays is of utmost importance in a wealth of science areas. We exposed isolated water isotopologues to short x-ray pulses from a free-electron laser and detected momenta of all produced ions in coincidence. By combining experimental results and theoretical modeling, we identify significant structural dynamics with characteristic isotope effects in H 2 O 2+ , D 2 O 2+ , and HDO 2+ , such as asymmetric bond elongation and bond-angle opening, leading to two-body or three-body fragmentation on a timescale of a few femtoseconds. A method to disentangle the sequences of events taking place upon the consecutive absorption of two x-ray photons is described. The obtained deep look into structural properties and dynamics of dissociating water isotopologues provides essential insights into the underlying mechanisms.
47 OTHER INSTRUMENTATION↗
Catalytic Water Electrolysis by Co–Cu–W Mixed Metal Oxides: Insights from X-ray Absorption Spectroelectrochemistry
Mixed metal oxides (MMOs) are a promising class of electrocatalysts for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Despite their importance for sustainable energy schemes, our understanding of relevant reaction pathways, catalytically active sites, and synergistic effects is rather limited. Here, we applied synchrotron-based X-ray absorption spectroscopy (XAS) to explore the evolution of the amorphous Co–Cu–W MMO electrocatalyst, shown previously to be an efficient bifunctional OER and HER catalyst for water splitting. Ex situ XAS measurements provided structural environments and the oxidation state of the metals involved, revealing Co 2+ (octahedral), Cu + / 2+ (tetrahedral/square-planar), and W 6+ (octahedral) centers. Operando XAS investigations, including X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), elucidated the dynamic structural transformations of Co, Cu, and W metal centers during the OER and HER. The experimental results indicate that Co 3+ and Cu 0 are the active catalytic sites involved in the OER and HER, respectively, while Cu 2+ and W 6+ play crucial roles as structure stabilizers, suggesting strong synergistic interactions within the Co–Cu–W MMO system. In conclusion, these results, combined with the Tafel slope analysis, revealed that the bottleneck intermediate during the OER is Co 3+ hydroperoxide, whose formation is accompanied by changes in the Cu–O bond lengths, pointing to a possible synergistic effect between Co and Cu ions. Our study reveals important structural effects taking place during MMO-driven OER/HER electrocatalysis and provides essential experimental insights into the complex catalytic mechanism of emerging noble-metal-free MMO electrocatalysts for full water splitting.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗