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At least 199 records · Page 11

Project 8: Measuring the tritium beta-decay spectrum using Cyclotron Radiation Emission Spectroscopy

Abstract. The goal of the Project 8 experiment is to measure the absolute neutrino mass using tritium beta decays and a new spectroscopic technique, Cyclotron Radiation Emission Spectroscopy (CRES). The first phase of Project 8 demonstrated that CRES could be used to detect single-electron cyclotron radiation and perform precision electron spectroscopy. We are in Phase II of the experiment, performing a 100-day measurement of the endpoint of the tritium spectrum. We will demonstrate the ability to measure the last ~2 keV of the beta-decay spectrum and explore the background rate at energies just above the endpoint; CRES has the potential for extremely low backgrounds. In Phase III we will demonstrate the ability to scale up the volume of the experiment. In Phase IV we will switch the source from molecular tritium to atomic tritium, which will avoid systematic uncertainties from the final states of the molecule. I will present the current status of Project 8 Phase II and the plans for Phases III and IV.

Oblath, Noah↗

Verification and Validation of Optimization of Replacement Portal Monitoring Replay Tools

The Los Alamos National Laboratory and the Johns Hopkins Applied Physics Laboratory (APL) are both developing optimization software to fulfill the objective of Phase III of the Replacement Portal Monitoring (RPM) Program for the Department of Homeland Security. The objective of the Phase III of the RPM Program is to conduct an evaluation of three RPM systems designed to enhance mission effectiveness, gain operational efficiencies, and to address emerging mission needs against the Countering Weapons of Mass Destruction (CWMD ) nuclear threat basis and special nuclear material (SNM) used in performance testing. As such this task involves the use of global optimization algorithms.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗

Linear canonical transformations of coherent and squeezed states in the Wigner phase space. III - Two-mode states

It is shown that the basic symmetry of two-mode squeezed states is governed by the group SP(4) in the Wigner phase space which is locally isomorphic to the (3 + 2)-dimensional Lorentz group. This symmetry, in the Schroedinger picture, appears as Dirac's two-oscillator representation of O(3,2). It is shown that the SU(2) and SU(1,1) interferometers exhibit the symmetry of this higher-dimensional Lorentz group. The mathematics of two-mode squeezed states is shown to be applicable to other branches of physics including thermally excited states in statistical mechanics and relativistic extended hadrons in the quark model.

Han, D.↗

Brigham City Hydro Generation Project

Brigham City owns and operates its own municipal power system which currently includes several hydroelectric facilities. This project was to update the efficiency and capacity of current hydro production due to increased water flow demands that could pass through existing generation facilities. During 2006-2012, this project completed efficiency evaluation as it related to its main objective by completing a feasibility study, undergoing necessary City Council approvals and required federal environmental reviews. As a result of Phase 1 of the project, a feasibility study was conducted to determine feasibility of hydro and solar portions of the original proposal. The results indicated that the existing Hydro plant which was constructed in the 1960’s was running at approximately 77% efficiency or less. Brigham City proposes that the efficiency calculations be refined to determine the economic feasibility of improving or replacing the existing equipment with new high efficiency equipment design specifically for the site. Brigham City completed the Feasibility Assessment of this project, and determined that the Upper Hydro that supplies the main culinary water to the city was feasible to continue with. Brigham City Council provided their approval of feasibility assessment’s results. The Upper Hydro Project include removal of the existing powerhouse equipment and controls and demolition of a section of concrete encased penstock, replacement of penstock just upstream of the turbine inlet, turbine bypass, turbine shut-off and bypass valves, turbine and generator package, control equipment, assembly, start-up, commissioning, Supervisory Control And Data Acquisition (SCADA), and the replacement of a section of conductors to the step-up transformer. Brigham City increased the existing 575 KW turbine and generator with an 825 KW turbine and generator. Following the results of the feasibility assessment Brigham City pursued required environmental reviews with the DOE and the U.S. Fish and Wildlife Services (USFWS) concurring with the National Environmental Policy Act of 1969 (NEPA) It was determined that Brigham City’s Upper Hydroelectric Power Plant upgrade would have no effect to federally listed or candidate species. However Brigham City has contributed a onetime lump sum towards Bonneville cutthroat trout conservation in the Northern Bonneville Geographic Management Unit with the intention to offset any impacts from the Upper Hydro Project needed to move forward with design and construction and is sufficient for NEPA compliance. No work was done in the river or river bank. During construction, the penstock was disconnected and water was diverted through and existing system around the powerhouse and back into the water system. The penstock, which is currently a 30-inch steel pipe, would be removed and replaced with a new section of 30-inch pipe. Brigham City worked with the DOE and was awarded a new modification and the permission to proceed with Phase III of our Hydro Project in Dec. 2013; with the exception to the modification of the award for the construction phase. Brigham City developed and issued a Request for Proposal for Engineer and Design vendor. Sunrise Engineering was selected for the Design and throughout the Construction Phase of the Upper Hydroelectric Power Plant. Brigham City conducted a Kickoff Meeting with Sunrise June 28, 2013 and received a Scope of Work Brigham City along with engineering firm sent out a RFP for Turbine, Generator and Equipment for Upper Hydro. We select Turbine/Generator Equipment from Canyon Industries located in Deming, WA. DOE awarded Brigham City a new modification and the permission to proceed with Phase III Construction of our Hydro Project. Brigham City Crews removed existing turbine/generator and old equipment alone with feeder wires coming into the building basically giving Caribou Construction an empty shell to begin demolition. Brigham City contracted with Caribou Construction from Jerome, Idaho for the Upper Power Plant construction. A kickoff meeting was June 24, 2014 and demolition was immediately started on building. Because of a delivery delay of Turbine, Generator and Equipment from Canyon Brigham City had to request another extension for the final date of completion. DOE awarded modification (.007) to Brigham City with a new completion date of August 1, 2015. The Turbine has had a few adjustments to help with efficiency; but the Generator had a slight vibration when generator got hot so Canyon Industries had U S Motor’s that manufactured the generator come to check out the issue. The other Equipment seems to be running normal. Brigham City, Sunrise Engineering and Canyon Industries met to determine what the vibration in the generator was and how to solve the issue Us Motor’s found some welds that failed: they have been repaired. U S Motor’s delivered the repaired generator Feb. 17, 2015. Canyon Industries arranged for a crane to installed generator in Power Plant. U S Motor’s balanced and wired generator. Plant Operators put the generator back on line. Canyon Industries returned and gave their approval to keep Hydro online. After Hydro was put back into operations it kept going off line because of overheating issues. Canyon Industries returned and replaced sensors and adjusted them to the proper settings for normal operations. Brigham City added additional steel screens to windows to increase air flow in Power Plant Building. After construction phase of the Upper Hydro Plant some landscaping has been restored around the building additional gravel brought in and leveled out and the road that was cut through for conduits to run wires. A retaining wall was installed to protect penstock. The Upper Hydro Plant is complete and in full operations. The final reimbursement was submitted.

13 HYDRO ENERGY↗

Enhanced terrestrial Fe(II) mobilization identified through a novel mechanism of microbially driven cave formation in Fe(III)-rich rocks

Most cave formation requires mass separation from a host rock in a process that operates outward from permeable pathways to create the cave void. Given the poor solubility of Fe(III) phases, such processes are insufficient to account for the significant iron formation caves (IFCs) seen in Brazilian banded iron formations (BIF) and associated rock. Here in this study we demonstrate that microbially-mediated reductive Fe(III) dissolution is solubilizing the poorly soluble Fe(III) phases to soluble Fe(II) in the anoxic zone behind cave walls. The resultant Fe(III)-depleted material (termed sub muros) is unable to maintain the structural integrity of the walls and repeated rounds of wall collapse lead to formation of the cave void in an active, measurable process. This mechanism may move significant quantities of Fe(II) into ground water and may help to explain the mechanism of BIF dissolution and REE enrichment in the generation of canga. The role of Fe(III) reducing microorganism and mass separation behind the walls (outward-in, rather than inward-out) is not only a novel mechanism of speleogenesis, but it also may identify a previously overlooked source of continental Fe that may have contributed to Archaean BIF formation.

54 ENVIRONMENTAL SCIENCES↗

Risk Characterization Research for Artemis II: Human Factors and Behavioral Performance

BACKGROUND Artemis II will be the first time NASA astronauts go beyond low-Earth orbit (LEO) since the Apollo era, and the first astronauts heading into space in the Orion vehicle. As such, it provides a critical opportunity to refine our understanding of the likelihood and consequences associated with the Behavioral Medicine (BMed), Team, Human System Integration Architecture (HSIA), and Sleep Risks, and prepare for future Moon and Mars missions. However, Artemis II research efforts are uniquely shaped by in-mission data collection constraints. There is currently no in-mission crew time available to complete measures. In-mission data will need to be collected unobtrusively from available data streams (e.g., audiovisual, existing records such as schedules, and actigraphy). Accordingly, the overarching goal of our research is to utilize Artemis II data to further define the likelihood and consequences of these risks, and to create an unobtrusive research infrastructure that can be expanded to include future Artemis missions. This goal spans four aims across three research phases: (1) identify and operationally define key performances metrics and constructs across the four aforementioned risks, (2) develop an unobtrusive methodology and coding scheme for in-mission data collection, (3) characterize performance decrements due to Bmed, Team, HSIA, and Sleep Risks, and (4) develop a data infrastructure for future Artemis missions. The following details results of Phase I efforts in which we address Aims 1 and 2 to develop an unobtrusive measurement plan and coding scheme to capture key constructs, contributing factors, and performance decrements across each risk area. METHOD As part of Phase I, we conducted an interdisciplinary literature review and consulted with SMEs to identify unobtrusive methodologies that leverage text, audio, and/or video data as well as conceptualize key performance metrics, contributing factors, and BMed, Team, HSIA, and Sleep risk constructs related to performance decrements. The Phase I effort resulted in a finalized pre- and post-mission protocol for Artemis II, along with a measurement and coding scheme for in-mission Artemis II data. Phase II will involve data collection from the upcoming Artemis II mission. Phase III will include data processing, coding, depiction, analysis, and report writing of the Artemis II data. RESULTS & DISCUSSION To date, we have completed Phase I efforts. Specifically, we identified BMed, Team, HSIA, and Sleep risk constructs related to performance metrics, summarized how these constructs can be measured using audiovisual data collected during the mission, and worked with NASA’s HFBP Element to finalize a data collection protocol that leverages audiovisual input from the Orion spacecraft system. Our protocol includes novel unobtrusive methodologies that adhere to in-mission data streams and subsequent constraints (e.g., limited storage space on GoPro cameras, ambient noise impeding audio files) to best capture in-mission phenomena across each risk area. We will present our results from Phase I efforts, namely best practices for unobtrusive measurement as identified through literature reviews and SME consultation as well as codebook excerpts for use in Artemis II. We will include a description of planned work as we prepare for Phase II and Phase III of this research plan and the Artemis II mission itself. SUMMARY We describe progress on our Human Factors and Behavioral Performance Research for Artemis II study.

behavioral health↗

Sodium superionic conduction in tetragonal Na{sub 3}PS{sub 4}

Highlights: • Na{sub 3}PS{sub 4} base solid electrolytes were fabricated by various synthetic routes. • The formation of phases in Na{sub 3+5x}P{sub 1–x}S{sub 4} depends on reaction conditions. • Tetragonal phase III showed the highest conductivity of 3.39 × 10{sup -3} S cm{sup -1}at 25 °C. • Structural analysis revealed the 3D conduction pathway in the tetragonal phase III. • Na{sub 3}PS{sub 4} functions as a solid electrolyte in all-solid-state sodium batteries. - Abstract: Sodium superionic conductors are highly promising as solid electrolytes for all-solid-state sodium batteries, with the capacity to improve energy and power density of liquid-electrolyte-based batteries and to address their safety issues. However, the ionic conductivity of sodium electrolytes remains roughly one order of magnitude lower than that of lithium systems. Herein, we report a synthesis method for a sodium superionic conductor, tetragonal Na{sub 3}PS{sub 4}, with an ionic conductivity of 3.39 × 10{sup −3} Scm{sup −1} at 25 °C—the highest value yet reported among sulfide-type sodium conductors. The high conductivity is achieved through quenching from 700 °C, which introduces sodium vacancies, and annealing at 450 °C, which increases vacancies and expands lattice volume. The phase is comprised of a framework of isolated PS{sub 4} tetrahedra, with partial distribution of Na over 3D pathways. The high intrinsic conductivity together with low grain boundary contribution and soft mechanical properties make Na{sub 3}PS{sub 4} a promising candidate for sodium solid electrolytes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Analysis of WakeVAS Benefits Using ACES Build 3.2.1

The FAA and NASA are currently engaged in a Wake Turbulence Research Program to revise wake turbulence separation standards, procedures, and criteria to increase airport capacity while maintaining or increasing safety. The research program is divided into three phases: Phase I near term procedural enhancements; Phase II wind dependent Wake Vortex Advisory System (WakeVAS) Concepts of Operations (ConOps); and Phase III farther term ConOps based on wake prediction and sensing. This report contains an analysis that evaluates the benefits of a closely spaced parallel runway (CSPR) Phase I ConOps, a single runway and CSPR Phase II ConOps and a single runway Phase III ConOps. A series of simulation runs were performed using the Airspace Concepts Evaluation System (ACES) Build 3.21 air traffic simulator to provide an initial assessment of the reduction in delay and cost savings obtained by the use of a WakeVAS at selected U.S. airports. The ACES simulator is being developed by NASA Ames Research Center as part of the Virtual Airspace Modelling and Simulation (VAMS) program.

Smith, Jeremy C.↗

Deep Controlled Source Electro-Magnetic Sensing: A Cost Effective, Long-Term Tool for Sequestration Monitoring

The proposed system was designed to operate as a permanent, autonomous monitoring and data collection system that can provide much higher temporal data density than can be achieved economically with 3-Dimensional (3D) seismic surveys. It can operate over broad areas for long periods of time providing full 3D data sets on a monthly basis at a very low cost. By borrowing techniques commonly used in marine CSEM, structural information from background seismic surveys can be incorporated into the CSEM modeling to provide high resolution models of CO 2 progression within reservoirs. The system uses borehole-based vertical-electric-dipole sources placed at reservoir depths in the formation. The electric and magnetic fields induced by this source are received on the surface using an array of stations. The project was conducted in three phases. Phase I demonstrated the feasibility of the system to collect static/reference data at the Ketzin CO 2 storage pilot site in Germany. In Phase I, numerical modeling was used to determine the optimal configurations and requirements for sensor sensitivity and data accuracy. Based on the model results, existing hardware and software were modified. The CSEM system was then field tested at the Ketzin site. The data were imaged and the results were compared with independent studies of the reservoir and overburden geo-electrical characteristics. Phase II demonstrated the ability to provide sensitive, cost-effective measurement of changes in reservoir properties and changes in the overlying formations using a second round of measurements at the Ketzin site. A prototype autonomous recording system was developed and tested as a subset of the measurement points. Phase III of the project quantified the advantages (and disadvantages) of the fully autonomous data collection subsystems by comparing them with repeated measurements made with mobile stations. The Phase III also provided an additional time point in measuring post-closure changes in and above the Ketzin CO 2 injection site. Validation of the CSEM field survey results were completed using a method such as other alternative and available field site data.

58 GEOSCIENCES↗

NIAC: The NASA Innovative Advanced Concepts Program

The NASA Innovative Advanced Concepts (NIAC) Program nurtures visionary ideas that could transform future NASA missions with the creation of breakthroughs - radically better or entirely new aerospace concepts - while engaging America's innovators and entrepreneurs as partners in the journey. NIAC projects study innovative, technically credible, advanced concepts that could one day “Change the Possible” in aerospace. NIAC supports innovative research through three phases of study, each competitively awarded. Phase I studies are for nine-month efforts to explore the overall viability of visionary concepts. Phase II studies further develop the most promising Phase I concepts for up to two years, prepare a roadmap for further development, and explore potential transition options within NASA and beyond. Phase III studies are designed to strategically transition the most promising NIAC concepts to other NASA programs, other government agencies, or commercial partners. Since 2011, NIAC has funded 128 Phase I, 51 Phase II, and 2 Phase III studies. This paper provides an update on NIAC’s history and current role in supporting NASA’s sustained investments in advanced aerospace technology development.

Innovation↗

TPSAS-NF1676L-13678-DND

An area that shows promise in enhancing structural integrity of aircraft and aerospace structures is integral stitched composite technology. The most recent generation of this technology is the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept. The goal of the PRSEUS concept is to provide damage-containment capability for composite structures while reducing overall structural weight. The National Aeronautics and Space Administration, the Boeing Company, and the Federal Aviation Administration (FAA) have partnered in an effort to assess the damage-containment features of a full-scale curved PRSEUS panel using the FAA Full-Scale Aircraft Structural Test Evaluation and Research facility. The background, test plan, fixture modifications, pre-test analysis, and planned experimental procedure were presented at the 2011 Aircraft Airworthiness and Sustainment Conference. This follow-on paper and presentation will provide details of the experimental procedure, test results, nondestructive inspection results, and preliminary test analysis comparison. The test program included three phases of loading and inspections: Phase I, as-built; Phase II, with barely visible impact damage (BVID); and Phase III, with a two-bay notch severing the central stiffener. Axial tension, internal pressure, and combined axial tension and internal pressure load conditions were applied during each phase using load levels that demonstrate compliance with the strength, deformation, and damage-tolerance requirements of Title 14 Code of Federal Regulations Part 25. Pressure loads were based on an operating pressure of 9.2 psi, designated as 1P, and the axial loads were based on a design limit load (DLL) of 227 kip. The Phase I test results provided a baseline. First, 50 percent limit-load levels were applied for each of the three load cases to verify proper load introduction and repeatability by examining strain and displacement results. Next, three limit-load cases were applied: limit pressure of 12.2 psi (1.33 P), axial DLL of 227 kip, and combined 1P pressure and axial DLL. Linear strain and displacement results were observed in all load cases. For Phase-II testing, the panel was impacted to introduce BVID with an energy of 40 ft-lb, with the impact located between the central stringer stitch line and flange edge. The impact created non-penetrating visual damage with fiber breaks and delamination between the skin and stringer flange. Limit-load conditions were applied followed by pressure overload of 18.4 psi (2P) and ultimate load conditions, defined as 1.5 times DLL. Inspections were performed after each load case; no damage growth was observed. For Phase-III testing, a two-bay notch was machined severing the central stiffener. The panel was then subjected to limit-load conditions, followed by combined 1P pressure while increasing axial tension load to catastrophic failure. As limit combined loads were approached, damage initiation was observed in the form of 45? splitting at 1P + 79% DLL. Axial loading was increased to 1P + 150 percent DLL causing damage to propagate to the adjacent stringer flanges. Damage was contained within the two-bay region by the stitching rows up to 1P + 176% DLL. Axial load was further increased until catastrophic failure, when a stringer rod failed at 1P + 192% DLL. These test results further verify the damage containment features of the PRSEUS concept and suggest its appropriateness for future flight vehicles.

Andrew Bergan↗

Hydrogen-Doped Polymeric Carbon Monoxide at High Pressure

The ability to control materials stability, bonding, and transformation by thermo-mechanical and chemical means is significant for development of high-energy-density extended solids. We report that doping hydrogen (~10%) in carbon monoxide (CO) can greatly lower the polymerization pressure of CO and enhance the stability of recovered polymeric CO products at ambient conditions. Hydrogen-doped CO crystallizes into well-grown dendrites of β-CO-like phase at 3.2 GPa, which polymerizes to highly unsaturated black polymer (phase I) at ~4.7 (5.8) GPa. Upon further compression, this highly colored polymer transforms into a translucent 3D network structure (phase II) at 6–7 (10–17) GPa and then a transparent 2D layer structure (phase III) at 20–30 (30–60) GPa. A similar series of transformations are also found in pure CO but at considerably higher transition pressures, as noted in parentheses. All polymeric phases are recoverable at ambient conditions, exhibiting an array of phase stability and novel properties such as chemically unstable phase I, highly luminescent phase II, and highly transparent layered phase III. The density of recovered products ranges from ~2.3 g/cm 3 to 3.6 g/cm 3 , depending on the pressure recovered. The recovered products are highly disordered but slowly decompose to crystalline solids of anhydrous polymeric oxalic acid while exhibiting interesting crystal morphologies such as nm-cobs, nm-lamellar layers, and μm-bales. Here, the present first-principles MD simulations suggest that the polymerization occurs at 6 (or 10) GPa in H 2 -doped (or pure) CO. While not directly participating in the reaction, the role of H 2 molecules is to enhance the mobility of CO molecules leading to the polymerization.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

San Marco D/L Explorer

ti March 26, 1964, Centro Ricerche Aerospaziali (CRA) successfully launched a two-stage Nike sounding rocket from the Santa Rita launch platform off the Kenya coast, concluding Phase I. It carried basic elements of the San Marco science instrumentation and served further to flight qualify these canponents as well as provide a means of check-out of range instrumentation and equipment. The second phase culminated in the launch of the San Marco-I Spacecraft fran Wallops Island on a Scout vehicle on December 15, 1964. This launch derronstrated the readiness of the CRA launch crews for Phase III operations and qualified the basic spacecraft design. In addition it confirmed the usefulness and reliability of the drag balance device for accurate determinations of air density values and satellite attitude. phase III was completed with the launching of San Marco-11 frcm the San Marco platform off the coast of Kenya on April 26, 1967. ?he San Marco-II carried the same instrunentation as the San Marco-I, but the equatorial orbit permitted a more detailed study to be made of density variations versus altitude in the equatorial region. Ihe successful launch also served to qualify the San Marco Range as a reliable facility for future satellite launches. The successful culmination of the first San Marco endeavor paved the way for still closer collaboration in future space explorations.

Source record↗

Validation of measurements of ventilation-to-perfusion ratio inequality in the lung from expired gas

The analysis of the gas in a single expirate has long been used to estimate the degree of ventilation-perfusion (Va/Q) inequality in the lung. To further validate this estimate, we examined three measures of Va/Q inhomogeneity calculated from a single full exhalation in nine anesthetized mongrel dogs under control conditions and after exposure to aerosolized methacholine. These measurements were then compared with arterial blood gases and with measurements of Va/Q inhomogeneity obtained using the multiple inert gas elimination technique. The slope of the instantaneous respiratory exchange ratio (R slope) vs. expired volume was poorly correlated with independent measures, probably because of the curvilinear nature of the relationship due to continuing gas exchange. When R was converted to the intrabreath Va/Q (iV/Q), the best index was the slope of iV/Q vs. volume over phase III (iV/Q slope). This was strongly correlated with independent measures, especially those relating to inhomogeneity of perfusion. The correlations for iV/Q slope and R slope considerably improved when only the first half of phase III was considered. We conclude that a useful noninvasive measurement of Va/Q inhomogeneity can be derived from the intrabreath respiratory exchange ratio.

NASA Discipline Cardiopulmonary↗

Distributed Acoustic Sensing (DAS) Seismic Monitoring of CO 2 Injected for Enhanced Oil Recovery in Northern Michigan

As part of the Midwest Regional Carbon Sequestration Partnership (MRCSP) Phase III project, a monitoring study was conducted to assess the effectiveness of DAS (Distributed Acoustic Sensing) -based VSP (Vertical Seismic Profiling) technology for delineating CO 2 injected into the Silurian-age pinnacle reefs in northern Michigan, the host rocks for the MRCSP Phase III demonstration project. The DAS VSP study was conducted in the Chester 16 reef, one of several reefs in Otsego County Michigan that is operated by Core Energy, LLC, of Traverse City, Michigan.

47 OTHER INSTRUMENTATION↗

Unmanned Aerial Vehicle Synthetic Aperture RADAR for Surface Change Monitoring

Space-based and airplane-based synthetic aperture RADAR (SAR) can monitor ground height using interferometric SAR (InSAR) collections. However, fielding the airplane-based SAR is expensive and coordinating the frequency and timing of ground experiments with space-based SAR is challenging. This research explored the possibility of using a small, mobile unmanned aerial vehicle- base (UAV) SAR to see if it could provide a quick and inexpensive InSAR option for the Source Physics Experiment (SPE) Phase III project. Firstly, a local feasibility collection using a UAV-based SAR showed that InSAR products and height measurements were possible, but that in-scene fiducials were needed to assist in digital elevation model (DEM) construction. Secondly, an InSAR collection was planned and executed over the SPE Phase III site using the same platform configuration. We found that the image formation by the SAR manufacturer creates discontinuities, and that noise impacted the generation and accuracy of height maps. These processing artifacts need to be overcome to generate an accurate height map.

47 OTHER INSTRUMENTATION↗

Advances in the Recovery of Uranium from Seawater: Studies Under Real Ocean Conditions

The objective of this project was to move the testing of uranium adsorbents from the laboratory to the field. We were successfully able to test fibers in both a flume and ocean environment under varying conditions to quantify the adsorptive properties and uranium uptake of adsorbents under coastal ocean conditions. Through this testing we have identified numerous challenges to be overcome prior to large-scale deployment of these fibers This project began in Phase I with laboratory experiments examining the effects of flow rates and water filtration on the absorption of uranium to fibers in flowthrough columns. In this experiment we found that fibers adsorb most efficiently at a flow rate of 250 ml/min, on a per liter basis. However faster flow rates increase exposure volume and allowed for slightly greater total U absorption. Therefore a balance between current speeds that are too fast and potentially break down fibers and those that are slower will be important to consider, alongside bio-fouling and exposure time, when deciding which current regimes are best to place fibers in the ocean. Phase II examined biofouling, comparing exposure of fibers in filtered flume water to that in a coastal ocean environment. Results from the dock and flume parallel experiment indicate a strong effect of biofouling on the capacity of the adsorbent fibers to adsorb uranium towards the very end of the experiment. Dock and flume samples showed comparable adsorption rates with the flume maximum achieved at day 49 with an adsorbance of 3.4 g U/kg-ads while the dock maximum was reached at day 42 with an adsorbance of 2.7 g U/kg-ads. Biofouling mitigation techniques were also examined. A comparison of 5 m and 12 m samples showed less growth at 12 meters where there is less light as well as less growth on the copper cages, which are toxic to many marine organisms. Overall despite biofouling, particles and other elements present, the fibers adsorbed uranium up to 2.7 g U/kg-ads in our open water dock experiments. This is lower than the maximum achieved in the flume of 3.4 g U/kg-ads and much lower than rates observed with synthetic seawater in laboratory experiments. Phase III involved two parts: working at Woods Hole Oceanographic Institution (WHOI) we examined the feasibility of reusing fibers after ocean deployment. Fiber reuse is an important consideration for operational costs associated with deployment. At present our data implies that reuse after open ocean exposure may not be significantly more effective than a single long deployment of fibers. The second part of Phase III involved collaboration with A. Slocum and M. Haji at MIT to examine the effects of various enclosures for fibers. This also involved testing a rotating system, designed to be deployed as part of an offshore wind turbine.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗

Ventilatory inhomogeneity determined from multiple-breath washouts during sustained microgravity on Spacelab SLS-1

We used multiple-breath N2 washouts (MBNW) to study the homogeneity of ventilation in four normal humans (mean age 42.5 yr) before, during, and after 9 days of exposure to microgravity on Spacelab Life Sciences-1. Subjects performed 20-breath MBNW at tidal volumes of approximately 700 ml and 12-breath MBNW at tidal volumes of approximately 1,250 ml. Six indexes of ventilatory inhomogeneity were derived from data from (1) distribution of specific ventilation (SV) from mixed-expired and (2) end-tidal N2, (3) change of slope of N2 washout (semilog plot) with time, (4) change of slope of normalized phase III of successive breaths, (5) anatomic lead dead space, and (6) Bohr dead space. Significant ventilatory inhomogeneity was seen in the standing position at normal gravity (1 G). When we compared standing 1 G with microgravity, the distributions of SV became slightly narrower, but the difference was not significant. Also, there were no significant changes in the change of slope of the N2 washout, change of normalized phase III slopes, or the anatomic and Bohr dead spaces. By contrast, transition from the standing to supine position in 1 G resulted in significantly broader distributions of SV and significantly greater changes in the changes in slope of the N2 washouts, indicating more ventilatory inhomogeneity in that posture. Thus these techniques can detect relatively small changes in ventilatory inhomogeneity. We conclude that the primary determinants of ventilatory inhomogeneity during tidal breathing in the upright posture are not gravitational in origin.

Prisk, G. Kim↗