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Numerical analysis of Microgravity Bubble Separation in Open Channels with ISS Bemchmarks

Spacecraft fluid systems often require specific considerations to operate in a manner similar to those on Earth. For instance, an open wedge shaped channel can serve as a pathway for passively separating bubbles from a liquid in a two phase flow, analogous to buoyancy effects on Earth. As the bubbles merge within the channel, they become increasingly confined in the wedge, driving them upwards and outwards toward the free surface due to capillary forces. These same forces ensure coalescence and allow the bubbles to escape through the free surface. However, in low gravity environments, a challenge arises when bubbles are not sufficiently large. Under such conditions, the bubbles tend to follow trajectories near their inscribed elevations, never fully leaving the liquid. Such unseparated bubbles can lead to downstream pump failure, cavitation, flow instabilities, dryout, and other adverse effects aboard spacecraft. Understanding and exploiting the underlying mechanisms behind this behavior is crucial for enhancing the reliability of passive capillary fluids management in space applications, including cryogenic and storable fuels transport, thermal fluids circulation, water recycling for life support, plant watering systems, and more. The joint German Aerospace Center (DLR) and NASA Capillary Channel Flow (CCF) experiment conducted on the International Space Station has provided an extensive publicly available database documenting such phenomena (https://science.nasa.gov/physical sciences informatics psi). Leveraging this resource, we aim to establish benchmarks for our numerical investigation of zero gravity bubbly two phase flow in open wedge channels. Specifically, we seek to quantitatively understand the mechanisms governing ‘inscribed’ bubble motion, considering the apparent interplay of two competing forces: Saffman lift (causing upward/outward motion) and the Magnus effect (causing downward/inward motion). Our cross cutting findings directly inform the development of robust passive phase separation methods within spacecraft plumbing systems.

bubble↗

DOE OSTI2021

Disruption of the Snf1 Gene Enhances Cell Growth and Reduces the Metabolic Burden in Cellulase-Expressing and Lipid-Accumulating Yarrowia lipolytica

Yarrowia lipolytica is known to be capable of metabolizing glucose and accumulating lipids intracellularly; however, it lacks the cellulolytic enzymes needed to break down cellulosic biomass directly. To develop Y. lipolytica as a consolidated bioprocessing (CBP) microorganism, we previously expressed the heterologous CBH I, CBH II, and EG II cellulase enzymes both individually and collectively in this microorganism. We concluded that the coexpression of these cellulases resulted in a metabolic drain on the host cells leading to reduced cell growth and lipid accumulation. The current study aims to build a new cellulase coexpressing platform to overcome these hinderances by (1) knocking out the sucrose non-fermenting 1 ( Snf1 ) gene that represses the energetically expensive lipid and protein biosynthesis processes, and (2) knocking in the cellulase cassette fused with the recyclable selection marker URA3 gene in the background of a lipid-accumulating Y. lipolytica strain overexpressing ATP citrate lyase ( ACL ) and diacylglycerol acyltransferase 1 ( DGA1 ) genes. We have achieved a homologous recombination insertion rate of 58% for integrating the cellulases- URA3 construct at the disrupted Snf1 site in the genome of host cells. Importantly, we observed that the disruption of the Snf1 gene promoted cell growth and lipid accumulation and lowered the cellular saturated fatty acid level and the saturated to unsaturated fatty acid ratio significantly in the transformant YL163t that coexpresses cellulases. The result suggests a lower endoplasmic reticulum stress in YL163t, in comparison with its parent strain Po1g ACL-DGA1. Furthermore, transformant YL163t increased in vitro cellulolytic activity by 30%, whereas the “total in vivo newly formed FAME (fatty acid methyl esters)” increased by 16% in comparison with a random integrative cellulase-expressing Y. lipolytica mutant in the same YNB-Avicel medium. The Snf1 disruption platform demonstrated in this study provides a potent tool for the further development of Y. lipolytica as a robust host for the expression of cellulases and other commercially important proteins.

09 BIOMASS FUELS↗

DOE OSTI2025

Return on Investment and Sustainability of HVDC Links: Role of Diagnostics, Condition Monitoring, and Material Innovations

HVDC cable systems are becoming an upscaled technical option, compared to AC, because of various factors, including easier interconnections, lower losses, and longer transmission distances. In addition, renewables providing direct DC energy, electrified transportation, and aerospace where DC can be favored because of higher carried specific power all point in the direction of broad future usage of HV and MV DC links. However, contrary to AC, there is little return from on-field installation as regards long-term cable reliability and aging processes. This gap must be covered by intensive research, and contributing to this research is the purpose of this paper. The focus is on key points for HVDC (and MVDC) cable reliability and sustainability, from design modeling able to account for voltage transients and extrinsic aging (such as that caused by partial discharges) to the impact of aging on insulation conductivity (which rules the electric field distribution, thus aging rate). Also, recyclable and nanostructured materials, as well as health conditions, are considered. It is shown how cable design can account for accelerated aging due to voltage transients, as well as for aging-time dependence of conductivity, and how design can be free of extrinsic aging caused by PDs. Algorithms for health condition evaluations, which have additional value in a relatively new technology such as HVDC polymeric cables, are applied to insulation system aging under partial discharges, showing how they can provide an indication of insulation degradation globally or locally (weak spots) and of possible maintenance times. All of this can effectively contribute to reducing the risk of major cable breakdown and damage under operation, which would significantly affect the return on investment (ROI).

Montanari, Gian Carlo (ORCID:0000000320258693)↗

DOE OSTI2023

Control-oriented core-SOL-divertor model to address integrated burn and divertor control challenges in ITER

The real-time regulation of a burning plasma’s temperature and density, or burn control, will be necessary to produce high fusion power in future tokamaks like ITER. This is made more challenging due to the plasma’s nonlinear characteristics and the interdependence between the core-plasma and edge-plasma regions. For example, a raising plasma temperature leads to increasing reactivity and therefore to more alpha-particle heating, which further increases temperature. Furthermore, a raise of the fusion power increases the heat flow through the scrape-off-layer (SOL), which can compromise the integrity of the divertor without proper safeguards. For control design, a model-based approach is attractive because it can directly incorporate the nonlinear, coupled, burning-plasma dynamics into the design. To facilitate this design approach, a control-oriented core-SOL-divertor (CSD) model is presented in this work. In this CSD model, a core-plasma model captures the nonlinear dynamics of the core’s density and temperature, and a SOL-divertor model defines the plasma conditions at the separatrix and divertor including the heat load on the target plates. The core-plasma and SOL-divertor models are coupled through the exchange of various variables. In particular, the SOL-divertor model yields the separatrix temperature and the influx of recycled particles into the core-plasma. Further, these variables influence the power and particle balances captured by the core-plasma model. In return, the core-plasma model determines the intensity of the heat and particles fluxes across the separatrix, and this outflow strongly impacts the SOL-divertor model. Therefore, the power and density of the core-plasma, which can be readily modulated through external heating systems and pellet injection, can be viewed as control knobs for the SOL-divertor region in addition to the gas puffing. In simulations of the CSD model, it is demonstrated how external actuation can be utilized to meet burn control and divertor control objectives simultaneously.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

DOE OSTI2025

Tandem CO 2 valorisation to polycarbonate vitrimer and ethylene carbonate

The need for renewably sourced polymers has intensified with the worsening of global challenges such as emissions and plastic pollution. Here, we report a CO 2 -based poly(cyclohexene carbonate) (PCHC) vitrimer cured with zinc stearate that directly addresses both issues. Enhanced zinc dispersion within the network enabled faster curing and reprocessing than possible with zinc acetate systems, while maintaining consistent T g and mechanical integrity across multiple cycles. The vitrimer undergoes rapid glycolysis in ethylene glycol, valorisation into ethylene carbonate with up to 97% yield without additional catalyst. When applied to carbon fibre-reinforced polymers (CFRPs), applying this strategy enabled the development of sustainable CO 2 -based CFRP that can undergo full resin valorisation and recovery of clean, damage-free fibres. Collectively, this tandem CO 2 valorisation strategy—from vitrimer synthesis to fibre-reinforced composites and subsequent chemical valorisation—establishes multiple recycling and valorisation pathways and provides a promising routte for carbon capture and utilization as well as material recycling.

36 MATERIALS SCIENCE↗

DOE OSTI2024

Microbiome processing of organic nitrogen input supports growth and cyanotoxin production of Microcystis aeruginosa cultures

Abstract Nutrient-induced blooms of the globally abundant freshwater toxic cyanobacterium Microcystis cause worldwide public and ecosystem health concerns. The response of Microcystis growth and toxin production to new and recycled nitrogen (N) inputs and the impact of heterotrophic bacteria in the Microcystis phycosphere on these processes are not well understood. Here, using microbiome transplant experiments, cyanotoxin analysis, and nanometer-scale stable isotope probing to measure N incorporation and exchange at single cell resolution, we monitored the growth, cyanotoxin production, and microbiome community structure of several Microcystis strains grown on amino acids or proteins as the sole N source. We demonstrate that the type of organic N available shaped the microbial community associated with Microcystis, and external organic N input led to decreased bacterial colonization of Microcystis colonies. Our data also suggest that certain Microcystis strains could directly uptake amino acids, but with lower rates than heterotrophic bacteria. Toxin analysis showed that biomass-specific microcystin production was not impacted by N source (i.e. nitrate, amino acids, or protein) but rather by total N availability. Single-cell isotope incorporation revealed that some bacterial communities competed with Microcystis for organic N, but other communities promoted increased N uptake by Microcystis, likely through ammonification or organic N modification. Our laboratory culture data suggest that organic N input could support Microcystis blooms and toxin production in nature, and Microcystis-associated microbial communities likely play critical roles in this process by influencing cyanobacterial succession through either decreasing (via competition) or increasing (via biotransformation) N availability, especially under inorganic N scarcity.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2024

Direct extraction of lithium from ores by electrochemical leaching

With the rapid increase in lithium consumption for electric vehicle applications, its price soared during the past decade. To secure a reliable and cost-effective supply chain, it is critical to unlock alternative lithium extraction resources beyond conventional brine. In this study, we develop an electrochemical method to directly leach lithium from α-phase spodumene. We find the H 2 O 2 promoter can significantly reduce the leaching potential by facilitating the electron transfer and changing the reaction path. Upon leaching, β-phase spodumene shows a typical phase transformation to HAlSi 2 O 6 , while leached α-phase remains its original crystal phase with a lattice shrinkage. To demonstrate the scale-up potential of electrochemical leaching, we design a catalyst-modified high-throughput current collector for high loading of suspended spodumene, achieving a leaching current of 18 mA and a leaching efficiency of 92.2%. Electrochemical leaching will revolutionize traditional leaching and recycling processes by minimizing the environmental footprint and energy consumption.

25 ENERGY STORAGE↗

DOE OSTI2024

Experimental Determination of 𝛼 Widths of 21 Ne Levels in the Region of Astrophysical Interest: New 17 O +𝛼 Reaction Rates and Impact on the Weak 𝑠 Process

The efficiency of the weak 𝑠 process in low-metallicity rotating massive stars depends strongly on the rates of the competing 17 O ⁡(𝛼,𝑛)⁢ 20 Ne and 17 O ⁡(𝛼,𝛾)⁢ 21 Ne reactions that determine the potency of the 16 O neutron poison. Their reaction rates are poorly known in the astrophysical energy range of interest for core helium burning in massive stars because of the lack of spectroscopic information (partial widths, spin parities) for the relevant states in the compound nucleus 21 Ne . In this Letter, we report on the first experimental determination of the 𝛼-particle spectroscopic factors and partial widths of these states using the 17 O ⁡( 7 Li, 𝑡)⁢ 21 Ne 𝛼-transfer reaction. With these the 17 O ⁡(𝛼, 𝑛)⁢ 20 Ne and 17 O ⁡(𝛼, 𝛾)⁢ 21 Ne reaction rates were evaluated with uncertainties reduced by a factor more than 3 with respect to previous evaluations and the present 17 O ⁡(𝛼, 𝑛)⁢ 20 Ne reaction rate is more than 20 times larger. Finally, the present (𝛼, 𝑛)/(𝛼, 𝛾) rate ratio favors neutron recycling and suggests an enhancement of the weak 𝑠 process in the Zr-Nd region by more than 1.5 dex in metal-poor rotating massive stars.

direct reactions↗

DOE OSTI2021

Wafer-scale remote epitaxy of III-V semiconductors and applications

In conventional epitaxy of single-crystalline semiconductor materials, it is challenging to separate the grown layer with the substrate due to the strong bonding at the interface. Remote epitaxy is a recently discovered method to grow single-crystalline thin films on graphene, wherein the grown film can be exfoliated at the graphene interface to form freestanding membranes. Here, we present our recent development on remote epitaxy of III-V semiconductors. We show that directly growing 2D materials on III-V substrates as a remote epitaxy template is an ideal pathway that can eliminate transfer process-related defects and can realize wafer-scale process of remote epitaxy and substrate reuse. We present the strategies to grow 2D materials on the surface of III-V materials, which is much more challenging than thermally robust substrates such as SiO2/Si or sapphire. The nucleation of III-V on 2D material-coated III-V platforms via remote interaction is investigated both experimentally and theoretically. Lastly, we show advanced remote epitaxial platforms and optoelectronic applications enabled by remote epitaxy, and the capability to recycle the III-V substrates for repeated remote epitaxy and production of freestanding III-V thin films.

Kim, Hyunseok↗

DOE OSTI2021

Wafer-scale remote epitaxy of III-V semiconductors and applications

Kim, Hyunseok↗

NASA NTRS2012

Next Generation Life Support Project: Development of Advanced Technologies for Human Exploration Missions

Next Generation Life Support (NGLS) is one of several technology development projects sponsored by the National Aeronautics and Space Administration s Game Changing Development Program. NGLS is developing life support technologies (including water recovery, and space suit life support technologies) needed for humans to live and work productively in space. NGLS has three project tasks: Variable Oxygen Regulator (VOR), Rapid Cycle Amine (RCA) swing bed, and Alternative Water Processing. The selected technologies within each of these areas are focused on increasing affordability, reliability, and vehicle self sufficiency while decreasing mass and enabling long duration exploration. The RCA and VOR tasks are directed at key technology needs for the Portable Life Support System (PLSS) for an Exploration Extravehicular Mobility Unit (EMU), with focus on prototyping and integrated testing. The focus of the Rapid Cycle Amine (RCA) swing-bed ventilation task is to provide integrated carbon dioxide removal and humidity control that can be regenerated in real time during an EVA. The Variable Oxygen Regulator technology will significantly increase the number of pressure settings available to the space suit. Current spacesuit pressure regulators are limited to only two settings while the adjustability of the advanced regulator will be nearly continuous. The Alternative Water Processor efforts will result in the development of a system capable of recycling wastewater from sources expected in future exploration missions, including hygiene and laundry water, based on natural biological processes and membrane-based post treatment. The technologies will support a capability-driven architecture for extending human presence beyond low Earth orbit to potential destinations such as the Moon, near Earth asteroids and Mars.

Barta, Daniel J.↗

NASA NTRS2013

How Dead are Dead Galaxies? Mid-Infrared Fluxes of Quiescent Galaxies at Redshift 0.3< Z< 2.5: Implications for Star Formation Rates and Dust Heating

We investigate star formation rates of quiescent galaxies at high redshift (0.3 < z < 2.5) using 3D-HST WFC3 grism spectroscopy and Spitzer mid-infrared data. We select quiescent galaxies on the basis of the widely used UVJ color-color criteria. Spectral energy distribution fitting (rest frame optical and near-IR) indicates very low star formation rates for quiescent galaxies (sSFR approx. 10(exp −12)/yr. However, SED fitting can miss star formation if it is hidden behind high dust obscuration and ionizing radiation is re-emitted in the mid-infrared. It is therefore fundamental to measure the dust-obscured SFRs with a mid-IR indicator. We stack the MIPS-24 micron images of quiescent objects in five redshift bins centered on z = 0.5, 0.9, 1.2, 1.7, 2.2 and perform aperture photometry. Including direct 24 micron detections, we find sSFR approx. 10(exp −11.9) × (1 + z)(sup 4)/yr. These values are higher than those indicated by SED fitting, but at each redshift they are 20-40 times lower than those of typical star forming galaxies. The true SFRs of quiescent galaxies might be even lower, as we show that the mid-IR fluxes can be due to processes unrelated to ongoing star formation, such as cirrus dust heated by old stellar populations and circumstellar dust. Our measurements show that star formation quenching is very efficient at every redshift. The measured SFR values are at z > 1.5 marginally consistent with the ones expected from gas recycling (assuming that mass loss from evolved stars refuels star formation) and well above that at lower redshifts.

Galaxies↗

DOE OSTI2019

Synthesis of Anhydrous Acetates for the Components of Nuclear Fuel Recycling in Dialkylimidazolium Acetate Ionic Liquids [plus supplemental information]

A series of anhydrous acetate salts with uranium {[C 2 C 1 im][UO 2 (OAc) 3 ] (1), [C 2 C 2 im][UO 2 (OAc) 3 ] (2), and [C 4 C 1 im][UO 2 (OAc) 3 ] (3)}, lanthanides {[C 2 C 2 im] 2 [La(OAc) 5 ] (4) and [C 2 C 1 im] 2 [Nd(OAc) 5 ] (5)}, and strontium {[C 2 C 1 im] n [Sr- (OAc) 3 ] n (6)} (where C 2 C 1 im = 1-ethyl-3-methylimidazolium, C 2 C 2 im = 1,3-diethylimidazolium, C 4 C 1 im = 1-butyl-3-methylimi-dazolium, and OAc = acetate) have been prepared and structurally characterized. Both lanthanides and strontium are common components of the nuclear fuel waste, and their separation from uranium is an important but still challenging task. A new synthetic method with dialkylimidazolium acetate ionic liquids (ILs) as the solvent has been developed for the direct synthesis of homoleptic acetates from the corresponding hydrates and, unexpectedly, hardly soluble f-element oxides. Although the group of characterized compounds shows perfect structural variability, all actinide and lanthanide metal ions form monomeric complex anions where the metal cation coordinates to five ligands including two oxygen atoms in the case of uranium, as is commonly observed for uranyl compounds. Crystallographic analyses revealed that the complex [UO 2 (OAc) 3 ] - anions possess rather standard D 3h symmetry featuring a hexagonal-bipyramidal coordination environment, while the lanthanide anions [Ln(OAc) 5 ] 2- are fully asymmetric and the Ln 3+ cations are 10-coordinated in the form of a distorted bicapped tetragonal antiprism. This is the first report of lanthanide ions coordinated in this fashion. For Sr 2+ , 9-fold coordination through oxygen atoms in the form of a strongly distorted tricapped trigonal prism is observed. Furthermore, the crystallization of anhydrous, homoleptic, anionic acetate complexes from such a large variety of different metal salts appears to be due to the properties of dialkylimidazolium acetate ILs themselves, including enhanced basicity from the high concentration of free anions and their greater affinity for hydrogen-bonding solutes relative to metal cations.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2023

Crystal structure of calcium-ferrite type NaAlSiO4 up to 45 GPa

Abstract Alkali-rich aluminous high-pressure phases including calcium-ferrite (CF) type NaAlSiO4 are thought to constitute ~20% by volume of subducted mid-ocean ridge basalt (MORB) under lower mantle conditions. As a potentially significant host for incompatible elements in the deep mantle, knowledge of the crystal structure and physical properties of CF-type phases is therefore important to understanding the crystal chemistry of alkali storage and recycling in the Earth’s mantle. We determined the evolution of the crystal structure of pure CF-NaAlSiO4 and Fe-bearing CF-NaAlSiO4 at pressures up to ~45 GPa using synchrotron-based, single-crystal X-ray diffraction. Using the high-pressure lattice parameters, we also determined a third-order Birch-Murnaghan equation of state, with V0 = 241.6(1) Å3, KT0 = 220(4) GPa, and KT0′ = 2.6(3) for Fe-free CF, and V0 = 244.2(2) Å3, KT0 = 211(6) GPa, and KT0′ = 2.6(3) for Fe-bearing CF. The addition of Fe into CF-NaAlSiO4 resulted in a 10 ± 5% decrease in the stiffest direction of linear compressibility along the c-axis, leading to stronger elastic anisotropy compared with the Fe-free CF phase. The NaO8 polyhedra volume is 2.6 times larger and about 60% more compressible than the octahedral (Al,Si)O6 sites, with K0NaO8 = 127 GPa and K0(Al,Si)O6 ~304 GPa. Raman spectra of the pure CF-type NaAlSiO4 sample shows that the pressure coefficient of the mean vibrational mode, 1.60(7) cm–1/GPa, is slightly higher than 1.36(6) cm−1/GPa obtained for the Fe-bearing CF-NaAlSiO4 sample. The ability of CF-type phases to contain incompatible elements such as Na beyond the stability field of jadeite requires larger and less-compressible NaO8 polyhedra. Detailed high-pressure crystallographic information for the CF phases provides knowledge on how large alkali metals are hosted in alumina framework structures with stability well into the lowermost mantle.

Geochemistry & Geophysics↗

NASA NTRS1994

CELSS Antarctic Analog Project (CAAP): A New Paradigm for Polar Life Support and CELSS Research

The CELSS Antarctic Analog Project (CAAP) is a joint National Science Foundation (NSF) and National Aeronautics and Space Administration (NASA) project for the development, deployment and operation of CELSS technologies at the Amundsen-Scott South Pole Station. CAAP is implemented through the joint NSF/NASA Antarctic Space Analog Program (ASAP), initiated to support the pursuit of future NASA missions and to promote the transfer of space technologies to the NSF. Under a Memorandum of Agreement, the CAAP represents an example of a working dual agency cooperative project. NASA goals are operational testing of CELSS technologies and the conduct of scientific study to facilitate . technology selection, system design and methods development, including human dynamics as required for the operation of a CELSS. Although not fully closed, food production, water purification, and waste recycle and reduction provided by CAAP will improve the quality of life for the South Pole inhabitants, reduce logistics dependence, and minimize environmental impacts associated with human presence on the polar plateau. The CAAP facility will be highly integrated with the new South Pole Station infrastructure and will be composed of a deployed hardware facility and a research activity. This paper will include a description of CAAP and its functionality, conceptual designs, component selection and sizing for the crop growth chamber, crop production expectations, and a brief report on an initial on-site visit. This paper will also provide a discussion of issues associated with power and energy use and the applicability of CAAP to direct technology transfer to society in general and remote communities in particular.

Bubenheim, David L.↗

DOE OSTI2025

Influence of functional additives, fillers, and pigments on thermal and catalytic pyrolysis of polyethylene for waste plastic upcycling

Pyrolysis offers a relatively green and economical method to convert waste plastics into valuable chemicals and fuels without the need for harmful solvents, toxic chemicals, or costly high-pressure reactors. Despite its popularity among chemical upcycling technologies, industrial adoption suffers from feedstock heterogeneity, low-quality products, and catalyst deactivation. Most plastics in our daily lives are formulated with functional additives, fillers, and colorants. These additives remaining in end-of-life waste streams increase feedstock heterogeneity, creating a challenging issue in recycling plastics. Still, the potential impacts of additives on the chemical upcycling of plastics have been poorly understood. In this study, polyethylene compounded with a range of widely used additives (antioxidants, stabilizers, pigments, fillers, slip agents, and flame retardants) was subjected to both thermal pyrolysis and catalytic pyrolysis in different catalyst-to-feedstock contact modes. It showed that many inorganic additives, such as talc, kaolin, CaCO 3 , TiO 2 , carbon black, and zinc stearate, facilitated polymer decomposition during pyrolysis, increasing light hydrocarbons while also promoting aromatic and carbon residue formation. Conversely, antioxidants and stabilizers inhibited depolymerization, favoring heavier hydrocarbons. During catalytic pyrolysis with HZSM-5 zeolite, additives strongly enhanced aromatic and catalytic coke formation, especially when there was direct contact between plastics and catalysts. Although certain additives seem beneficial in the short term by promoting polymer cracking and improving the selectivity of aromatics, the transport of the additives and their degradation products and increased carbon coking can contaminate products, deactivate or modify catalysts, and foul reactors. These findings address a critical knowledge gap in effectively converting waste plastics via a greener route.

42 ENGINEERING↗

DOE OSTI2024

Continental rift evolution and drainage reorganization along the Dead Sea rift since the Miocene

The Dead Sea fault is a section of the Arabian-African plate boundary. Widespread field relations indicate that three major drainage systems (stages) occupied the landscape west of the Dead Sea fault since its initiation at ca. 20 Ma. Specifically, (1) an early to middle Miocene drainage system, only minorly reconfigured by the fault (all sediments of this system belong to the Hazeva Formation); (2) a late Miocene to early Pleistocene fault-parallel drainage system named Paran-Neqarot (all sediments of this system belong to the Arava and Zehiha Formations; and (3) the early Pleistocene to present drainage configuration. The temporal and spatial frameworks of drainage stage 1 are generally constrained by radiometric dating of interfingering volcanic units, and the onset and temporal and spatial frameworks of drainage stage 3 are well constrained by cosmogenic 10 Be surface exposure ages. The timing and longevity of the rift-parallel drainage (stage 2) have until now been evasive to direct dating. The overall time gap between stages 1 and 3 is ~12–13 million years. Thus, an early age (within this time gap) of stage 2 would imply an immediate response of drainage reorganization to rift tectonics, while a later age of this drainage system would imply a delayed response. We present 11 10 Be- 26 Al cosmogenic burial ages of alluvial and colluvial units related to the fault-parallel drainage system (stage 2), which collectively constrain the time of deposition of the Arava Formation sediments in the central Negev to ca. 8 Ma. The general lack of stratigraphic order, together with the large dispersion of ages both across and within the sampling sites, attests to significant recycling of sediments from drainage stage 1 into the Arava Formation deposits. The termination of Arava and Zehiha Formation sediment deposition at ca. 1.8 Ma was determined previously using cosmogenic exposure ages of desert pavements that cover the formations. Combining the previously published data with our new data, we established the longevity and character of the Paran-Neqarot drainage system. In conlcusion, this framework highlights the temporal aspect of drainage system build-up and collapse as it responded to transform and extensional plate boundary tectonics during the Neogene.

58 GEOSCIENCES↗

NASA NTRS1992

Characterization of the Water Soluble Component of Inedible Residue from Candidate CELSS Crops

Recycling of inorganic nutrients required for plant growth will be a necessary component of a fully closed, bioregenerative life support system. This research characterized the recovery of plant nutrients from the inedible fraction of three crop types (wheat, potato, and soybean) by soaking, or leaching, in water. A considerable portion of the dry weight of the inedible biomass was readily soluble (29 percent for soybean, 43 percent for wheat, and 52 percent for potato). Greater weight loss from potato was a result of higher tissue concentrations of potassium, nitrate, and phosphate. Approximately 25 percent of the organic content of the biomass was water soluble, while the majority of most inorganic nutrients, except for calcium and iron, were recovered in the leachate. Direct use of the leachates in hydroponic media could provide between 40-90 percent of plant nutrient demands for wheat, and 20-50 percent of demand for soybean and potato. Further evaluation of leaching as a component of resource recovery scheme in a bioregenerative system requires study of (1) utilization of plant leachates in hydroponic plant culture; and (2) conversion of organic material (both soluble and insoluble) into edible, or other useful, products.

Garland, Jay↗