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All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Cavern Leaching Monitoring CY18 And CY19

The U.S. Strategic Petroleum Reserve (SPR) is a crude oil storage system run by the U.S. Department of Energy (DOE). The reserve consists of 60 active storage caverns spread across four sites in Louisiana and Texas, near the Gulf of Mexico. Beginning in 2016, the SPR began executing U.S. congressionally mandated oil sales. The configuration of the reserve, with a total capacity of greater than 700 MMB, requires raw water to be used instead of saturated brine for oil withdrawals such as for sales. All sales will produce leaching within the caverns used for oil delivery. Thirty-six caverns had a combined total of over 29 MMB of water injected from CY18-CY19 for mandatory sales. Leaching effects were monitored in these caverns to understand how the sales operations may impact the long-term integrity of the caverns. While frequent sonars are the best way to monitor changes in cavern shape, they can be resource intensive for the number of caverns involved in sales and exchanges. An intermediate option is to model the leaching effects and see if any concerning features develop. The leaching effects were modeled here using the Sandia Solution Mining Code (SANSMIC). The results indicate that leaching induced features are not of concern in the majority of the caverns, 32 of 36. Four caverns, BH-107, BH-108, BH-114 and WH-114 have features that may grow with additional leaching and should be monitored as leaching continues in those caverns. Six caverns had post sale sonars which were compared with SANSMIC results. SANSMIC was able to capture the leaching well. A deviation in the SANSMIC and sonar cavern shapes was observed near the cavern floor in caverns with significant floor rise, a process not captured by SANSMIC. These results suggest SANSMIC is a useful tool for monitoring changes in cavern shape due to leaching effects related to sales and exchanges.

02 PETROLEUM↗
NASA NTRS2012

Water Information System Platforms Addressing Critical Societal Needs in the Mena Region

The MENA region includes 18 countries, the occupied Palestinian territories and Western Sahara. However, the region of interest for this study has a strategic interest in countries adjacent to the Mediterranean Sea, which includes, Morocco, Tunisia, Egypt, Lebanon and Jordan. The 90% of the water in the MENA region is used for the agriculture use. By the end of this century. this region is projected to experience an increase of 3 C to 5 C in mean temperatures and a 20% decline in precipitation (lPCC, 2007). Due to lower precipitation, water run-off is projected to drop by 20% to 30% in most of MENA by 2050 Reduced stream flow and groundwater recharge might lead to a reduction in water supply of 10% or greater by 2050. Therefore, per IPCC projections in temperature rise and precipitation decline in the region, the scarcity of water will become more acute with population growth, and rising demand of food in the region. Additionally, the trans boundary water issues will continue to plague the region in terms of sharing data for better management of water resources. Such pressing issues have brought The World Bank, USAID and NASA to jointly collaborate for establishing integrated, modern, up to date NASA developed capabilities for countries in the MENA region for addressing water resource issues and adapting to climate change impacts for improved decision making and societal benefit. This initiative was launched in October 2011 and is schedule to be completed by the end of2015.

Habib, Shahid↗
NASA NTRS2016

Community Extreme Tonnage User Service (CETUS): A 5000 Ton Open Research Facility in the United States

Large sample volume 5000 ton multi-anvil presses have contributed to the exploration of deep Earth and planetary interiors, synthesis of ultra-hard and other novel materials, and serve as a sample complement to pressure and temperature regimes already attainable by diamond anvil cell experiments. However, no such facility exists on the North American continent. We propose the establishment of an open user facility for COMPRES members and the entire research community, with the unique capability of a 5000 ton (or more) press, supported by a host of extant co-located experimental and analytical laboratories and research staff. We offer wide range of complementary and/or preparatory experimental options. Any required synthesis of materials or follow up experiments can be carried out controlled atmosphere furnaces, piston cylinders, multi-anvil, or experimental impact apparatus. Additionally, our division houses two machine shops that would facilitate any modification or custom work necessary for development of CETUS, one for general fabrication and one located specifically within our experimental facilities. We also have a general sample preparation laboratory, specifically for experimental samples, that allows users to quickly and easily prepare samples for ebeam analyses and more. A service we can offer to COMPRES community members in general, and CETUS visiting users specifically, is a multitude of analytical instrumentation literally steps away from the experimental laboratories. This year we will be pursuing site funding of our laboratories through NASA's Planetary Science Directorate, which should result in substantial cost savings to all visiting users, and supports our mission of interagency cooperation for the enhancement of science for all (see companion PSAMS abstract). The PI is in a unique position as an employee of Jacobs Technology to draw funding from multiple sources, including those from industry and commerce. We submitted a Planetary Major Equipment proposal to the NASA Emerging Worlds solicitation for the full cost of a press, with competitive bids submitted from Sumitomo, Rockland Research, and Voggenreiter. Additional funding is currently being sought from industry sources through the Strategic Partnerships Office at NASA JSC, External Pursuits Program Office on the JETS contract, and Jacobs corporate in the United States. Internal funding is available for JETS contract personnel to travel to large press locations worldwide to study set-up and operations. We also anticipate a fortuitous cost savings in installation of the large press because plans are already underway for major renovations to the entire experimental petrology suite within the next 2 years in order to accommodate our growing user base. Our focus as contract staff is on serving the scientific needs of our users and collaborators. We are seeking community expert input on multiple aspects of this proposed facility, such as the press type and design, access management, immediate projects, and future innovation initiatives.

Danielson, L.↗
NASA NTRS2007

Establishing a Near Term Lunar Farside Gravity Model via Inexpensive Add-on Navigation Payload

The Space Communications and Navigation, Constellation Integration Project (SCIP) is tasked with defining, developing, deploying and operating an evolving multi-decade communications and navigation (C/N) infrastructure including services and subsystems that will support both robotic and human exploration activities at the Moon. This paper discusses an early far side gravitational mapping service and related telecom subsystem that uses an existing spacecraft (WIND) and the Lunar Reconnaissance Orbiter (LRO) to collect data that would address several needs of the SCIP. An important aspect of such an endeavor is to vastly improve the current lunar gravity model while demonstrating the navigation and stationkeeping of a relay spacecraft. We describe a gravity data acquisition activity and the trajectory design of the relay orbit in an Earth-Moon L2 co-linear libration orbit. Several phases of the transfer from an Earth-Sun to the Earth-Moon region are discussed along with transfers within the Earth-Moon system. We describe a proposed, but not integrated, add-on to LRO scheduled to be launched in October of 2008. LRO provided a real host spacecraft against which we designed the science payload and mission activities. From a strategic standpoint, LRO was a very exciting first flight opportunity for gravity science data collection. Gravity Science data collection requires the use of one or more low altitude lunar polar orbiters. Variations in the lunar gravity field will cause measurable variations in the orbit of a low altitude lunar orbiter. The primary means to capture these induced motions is to monitor the Doppler shift of a radio signal to or from the low altitude spacecraft, given that the signal is referenced to a stable frequency reference. For the lunar far side, a secondary orbiting radio signal platform is required. We provide an in-depth look at link margins, trajectory design, and hardware implications. Our approach posed minimum risk to a host mission while maintaining a very low implementation and operations cost.

Folta, David↗
NASA NTRS1999

A Science Rationale for Mobility in Planetary Environments

For the last several decades, the Committee on Planetary and Lunar Exploration (COMPLEX) has advocated a systematic approach to exploration of the solar system; that is, the information and understanding resulting from one mission provide the scientific foundations that motivate subsequent, more elaborate investigations. COMPLEX's 1994 report, An Integrated Strategy for the Planetary Sciences: 1995-2010,1 advocated an approach to planetary studies emphasizing "hypothesizing and comprehending" rather than "cataloging and categorizing." More recently, NASA reports, including The Space Science Enterprise Strategic Plan2 and, in particular, Mission to the Solar System: Exploration and Discovery-A Mission and Technology Roadmap,3 have outlined comprehensive plans for planetary exploration during the next several decades. The missions outlined in these plans are both generally consistent with the priorities outlined in the Integrated Strategy and other NRC reports,4-5 and are replete with examples of devices embodying some degree of mobility in the form of rovers, robotic arms, and the like. Because the change in focus of planetary studies called for in the Integrated Strategy appears to require an evolutionary change in the technical means by which solar system exploration missions are conducted, the Space Studies Board charged COMPLEX to review the science that can be uniquely addressed by mobility in planetary environments. In particular, COMPLEX was asked to address the following questions: (1) What are the practical methods for achieving mobility? (2) For surface missions, what are the associated needs for sample acquisition? (3) What is the state of technology for planetary mobility in the United States and elsewhere, and what are the key requirements for technology development? (4) What terrestrial field demonstrations are required prior to spaceflight missions?

Source record↗
DOE OSTI2020

Optimal Efficiency and Operational Cost Savings: A Framework for Automated Rooftop PV Placement

Residential energy consumers are charged based on a utility rate structure, such as net metering or feed-in tariff. To lower consumers' electricity bills, expensive batteries are deployed to reduce the electricity fed from the grid during peak hours. However, strategic photovoltaic (PV) panel placement enables the reduction of operational energy cost while considering the spatial feasibility and efficiency for hosting rooftop PV. In this paper, we present a framework to automatically identify the optimal location of rooftop PV panels on residential buildings. Our framework integrates multiple workflows, including energy and environmental simulation, parametric modeling, and optimization to identify the ideal location of PV panels to balance the demand and supply at a building and community scale. These workflows are linked using the Grasshopper plug-in for Rhinoceros CAD software. The framework includes two different workflows, each satisfying a target for optimal PV placement: (a) maximizing PV panel efficiency, where users aim to maximize energy generation, and (b) minimizing operational energy cost, where "best'' panels are selected considering utility rates for operational energy cost. Our framework is demonstrated in a residential community in Fort Collins, Colorado, to generate the optimal PV placement for each of the two aforementioned targets. Results from the two workflows are compared to illustrate the effect of PV location and orientation on solar energy production efficiency and operational energy cost. The developed workflows are introduced as tools within the Grasshopper plug-in to investigate the solar potential of rooftop PV panels while taking into account factors such as contextual shading, utility rate structures, and buildings' energy demand profiles.

30 DIRECT ENERGY CONVERSION↗
NASA NTRS2012

Cis-Lunar Base Camp

Historically, when mounting expeditions into uncharted territories, explorers have established strategically positioned base camps to pre-position required equipment and consumables. These base camps are secure, safe positions from which expeditions can depart when conditions are favorable, at which technology and operations can be tested and validated, and facilitate timely access to more robust facilities in the event of an emergency. For human exploration missions into deep space, cis-lunar space is well suited to serve as such a base camp. The outer regions of cis-lunar space, such as the Earth-Moon Lagrange points, lie near the edge of Earth s gravity well, allowing equipment and consumables to be aggregated with easy access to deep space and to the lunar surface, as well as more distant destinations, such as near-Earth Asteroids (NEAs) and Mars and its moons. Several approaches to utilizing a cis-lunar base camp for sustainable human exploration, as well as some possible future applications are identified. The primary objective of the analysis presented in this paper is to identify options, show the macro trends, and provide information that can be used as a basis for more detailed mission development. Compared within are the high-level performance and cost of 15 preliminary cis-lunar exploration campaigns that establish the capability to conduct crewed missions of up to one year in duration, and then aggregate mass in cis-lunar space to facilitate an expedition from Cis-Lunar Base Camp. Launch vehicles, chemical propulsion stages, and electric propulsion stages are discussed and parametric sizing values are used to create architectures of in-space transportation elements that extend the existing in-space supply chain to cis-lunar space. The transportation options to cis-lunar space assessed vary in efficiency by almost 50%; from 0.16 to 0.68 kg of cargo in cis-lunar space for every kilogram of mass in Low Earth Orbit (LEO). For the 15 cases, 5-year campaign costs vary by only 15% from 0.36 to 0.51 on a normalized scale across all campaigns. Thus the development and first flight costs of assessed transportation options are similar. However, the cost of those options per flight beyond the initial operational capability varies by 70% from 0.3 to 1.0 on a normalized scale. The 10-year campaigns assessed begin to show the effect of this large range of cost beyond initial operational capability as they vary approximately 25% with values from 0.75 to 1.0 on the normalized campaign scale. Therefore, it is important to understand both the cost of implementation and first use as well as long term utilization. Finally, minimizing long term recurring costs is critical to the affordability of future human space exploration missions. Finally minimizing long term recurring costs is critical to the affordability of future human space exploration missions.

Merrill, Raymond G.↗
NASA NTRS2007

A Risk-Based Approach for Aerothermal/TPS Analysis and Testing

The current status of aerothermal and thermal protection system modeling for civilian entry missions is reviewed. For most such missions, the accuracy of our simulations is limited not by the tools and processes currently employed, but rather by reducible deficiencies in the underlying physical models. Improving the accuracy of and reducing the uncertainties in these models will enable a greater understanding of the system level impacts of a particular thermal protection system and of the system operation and risk over the operational life of the system. A strategic plan will be laid out by which key modeling deficiencies can be identified via mission-specific gap analysis. Once these gaps have been identified, the driving component uncertainties are determined via sensitivity analyses. A Monte-Carlo based methodology is presented for physics-based probabilistic uncertainty analysis of aerothermodynamics and thermal protection system material response modeling. These data are then used to advocate for and plan focused testing aimed at reducing key uncertainties. The results of these tests are used to validate or modify existing physical models. Concurrently, a testing methodology is outlined for thermal protection materials. The proposed approach is based on using the results of uncertainty/sensitivity analyses discussed above to tailor ground testing so as to best identify and quantify system performance and risk drivers. A key component of this testing is understanding the relationship between the test and flight environments. No existing ground test facility can simultaneously replicate all aspects of the flight environment, and therefore good models for traceability to flight are critical to ensure a low risk, high reliability thermal protection system design. Finally, the role of flight testing in the overall thermal protection system development strategy is discussed.

Wright, Michael J.↗
DOE OSTI2024

Tierra del Fuego Case Study Capacity Expansion Analysis

This case study, developed by Net Zero World Initiative and the Government of Argentina, examines least-cost decarbonization pathways for Tierra del Fuego, Argentina, utilizing renewable energy, energy storage, hydrogen, and other decarbonization technologies. Being the second largest natural gas producing province in Argentina, Tierra del Fuego has historically relied on natural gas for their energy sector needs. As they look at possible decarbonization pathways, they face challenges due to extreme weather conditions, isolation from the mainland, and low population density. The study utilizes the Engage web application for capacity expansion modeling, addressing both business-as-usual (BAU) and accelerated decarbonization scenarios, with varying degrees of electrification and carbon emission constraints. Key findings reveal that an interconnection with the mainland, high contribution of wind energy development on Tierra del Fuego, energy storage, and hydrogen, coupled with energy-efficient electrification technologies (such as heat pumps and electric vehicles), emerge as the most cost-effective solutions to decarbonize, significantly reducing carbon emissions and total system energy costs. The study explores self-generation and interconnection alternatives, demonstrating the economic advantage of an interconnection of Tierra del Fuego with the mainland, as an alternative to 100% local generation. Sensitivity analyses on wind data sources and temporal resolutions, as well as projected natural gas prices, highlight the influence of external factors on the feasibility of decarbonization pathways. Challenges identified include the practicality of phasing out natural gas, economic uncertainty, cost implications of long-term storage technologies as wind energy increases, and geographical limitations for wind generation. The case study concludes that while substantial emissions reductions can be achieved by 2050, and be competitive with conventional pathways, achieving a full 100% decarbonization by 2050 would entail higher costs, particularly due to the significant reliance on storage solutions with higher contribution of wind energy. The analysis offers valuable insights for policymakers and stakeholders in Argentina's energy sector, emphasizing the importance of strategic planning, investment in renewable energy and storage technologies, and careful consideration of local conditions in the transition towards Net Zero targets.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
NASA NTRS2021

Novel Ways to use the International Spacer Station as an Exploration Analog: International Progress in Planning "ISS4Mars"

In October 2020, International Space Station (ISS) Partner Agencies held a set of international workshops to solicit and develop creative and forward-looking ideas for using the ISS as an analog for preparation for Mars missions during its 3rd decade of operations. The workshops brought together participants from nine international space agencies or organizations, with stakeholders consisting of research managers, discipline experts, technology developers, flight physicians, flight operators, and astronauts. Breakout meetings and brainstorming sessions were conducted focusing on the following topics: Critical hazards and countermeasures for the transit to Mars; gravity transitions and early surface operations; environmental control and life support systems; food systems; human microbiome, microbial monitoring, and planetary protection; medical operations for Mars missions; isolation and confinement; autonomous systems and crew-centered autonomy; and communications delay effects on operations. In many cases the scenarios and approaches identified were compelling but challenging to implement under the current utilization structure used to manage the ISS for experiments. Following the series of workshops, a team of utilization leaders across the ISS partnership worked to compile the workshop recommendations and extract a set of use-cases with their prerequisites and constraints. The work considered the following aspects: what can be effectively done on ISS; which new technologies, approaches and scenarios are feasible; what alternatives could be considered; and what steps should be taken to enable integrated testing and future use of ISS as an analog for Mars missions. The final report will be published so that the use cases can be considered in each agency’s strategic planning processes. This paper will cover the process of international assessment in detail and how this process has influenced and broadened the vision of ISS utilization beyond single experiments to integrated studies and testing for future Mars missions. This approach to international collaboration informs both the next decade of international exploration research on the ISS and advancement of its utilization as an analog for deep space missions. For many of the participating partners, it also helps to frame the strategy for human research in Artemis as we begin planning for human missions to the moon. We conclude with a summary of the progress on the actions in the report and the additional implementation discussions that have occurred across the partnership.

Julie A Robinson↗
DOE OSTI2022

Residential Façade Upgrades: Market Assessment and Recommendations

In support of DOE’s move toward transformational whole-building upgrades and enclosure solutions, the Pacific Northwest National Laboratory (PNNL) and National Renewable Energy Laboratory (NREL) are partnering and collaborating with leading building science researchers and home-performance entities to identify and characterize technical and economic barriers to façade retrofits in an effort to identify market-viable façade solutions and opportunities for an actionable plan to transform the market. The project includes partnerships with Building Science Corporation (BSC) and a combination of strategic implementation partners with home-performance and retrofit expertise and industry contacts. The project will include expert advisory and review consultation from Lawrence Berkeley National Laboratory’s (LBNL’s) Residential Windows & Attachments team and Oak Ridge National Laboratory’s Building Envelope team. The project consists of three parts: 1. a market analysis that captures the current state of the façade retrofit market and includes housing characteristics and retrofit costs, façade retrofit approaches and materials, contractor business models and workforce requirements to support advanced façade approaches; 2. an economic analysis focused on the viability of advanced façade retrofit approaches and materials; and 3. field demonstration of façade retrofits that include enhanced insulation/air-sealing and window technologies in multiple climate zones. This report represents the market analysis, as outlined in item 1 above. The goal of this analysis is to provide a techno-economic study that supports comprehensive retrofits of residential enclosures that include traditional approaches, and integrated wall assemblies and windows that result in durable, energy efficient, and marketable strategies. This study will provide a better knowledge base regarding the viable market for façade retrofit strategies, identify the barriers to uptake, analyze economic opportunities, and develop documentation specifically aimed to overcome technical and market barriers associated with installation.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2021

A semi-supervised machine learning detector for physics events in tokamak discharges

Databases of physics events have been used in various fusion research applications, including the development of scaling laws and disruption avoidance algorithms, yet they can be time-consuming and tedious to construct. This paper presents a novel application of the label spreading semi-supervised learning algorithm to accelerate this process by detecting distinct events in a large dataset of discharges, given few manually labeled examples. A high detection accuracy (>85%) for H-L back transitions and initially rotating locked modes is demonstrated on a dataset of hundreds of discharges from DIII-D with manually identified events for which only 3 discharges are initially labeled by the user. Lower yet reasonable performance (~75%) is also demonstrated for the core radiative collapse, an event with a much lower prevalence in the dataset. Additionally, analysis of the performance sensitivity indicates that the same set of algorithmic parameters is optimal for each event. This suggests that the method can be applied to detect a variety of other events not included in this paper, given that the event is well described by a set of 0D signals robustly available on many discharges. Procedures for analysis of new events are demonstrated, showing automatic event detection with increasing fidelity as the user strategically adds manually labeled examples. Detections on Alcator C-Mod and EAST are also shown, demonstrating the potential for this to be used on a multi-tokamak dataset.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS2008

Engineering America's Future in Space: Systems Engineering Innovations for Sustainable Exploration

The National Aeronautics and Space Administration (NASA) delivers space transportation solutions for America's complex missions, ranging from scientific payloads that expand knowledge, such as the Hubble Space Telescope, to astronauts and lunar rovers destined for voyages to the Moon. Currently, the venerable Space Shuttle, which has been in service since 1981, provides U.S. capability for both crew and cargo to low-Earth orbit to construct the International Space Station, before the Shuttle is retired in 2010, as outlined in the 2006 NASA Strategic Plan. I In the next decade, NASA will replace this system with a duo of launch vehicles: the Ares I Crew Launch Vehicle/Orion Crew Exploration Vehicle and the Ares V Cargo Launch Vehicle/Altair Lunar Lander. The goals for this new system include increased safety and reliability, coupled with lower operations costs that promote sustainable space exploration over a multi-decade schedule. This paper will provide details of the in-house systems engineering and vehicle integration work now being performed for the Ares I and planned for the Ares V. It will give an overview of the Ares I system-level test activities, such as the ground vibration testing that will be conducted in the Marshall Center's Dynamic Test Stand to verify the integrated vehicle stack's structural integrity against predictions made by modern modeling and simulation analysis. It also will give information about the work in progress for the Ares I-X developmental test flight planned in 2009 to provide key data before the Ares I Critical Design Review. Activities such as these will help prove and refine mission concepts of operation, while supporting the spectrum of design and development tasks being performed by Marshall's Engineering Directorate, ranging from launch vehicles and lunar rovers to scientific spacecraft and associated experiments. Ultimately, the work performed will lead to the fielding of a robust space transportation solution that will carry international explorers and essential payloads for sustainable scientific discovery beyond planet Earth.

Dumbacher, Daniel L.↗
DOE OSTI2025

Transparent and Conductive Polyimide‐Ionene Hybrid Interlayers for High Performance and Cost‐Effective Semitransparent Organic Solar Cells

The contradiction between high transmittance and favorable conductivity poses a great challenge in developing effective cathode interlayer (CIL) materials with sufficient thickness tolerance, which hinders the further advancement of organic solar cells (OSCs). Herein, a completely new class of alcohol processable polyimide-ionene hybrids (PIIHs) is proposed by melding pyromellitic diimide (PMD) subunits into imidazolium-based ionenes backbone covalently. These PIIHs, named PMD-DI and PMD-PD, boast high transparency, suitable energy levels, and decent conductivity. A higher PMD content endows PMD-PD with improved work function tunability, electrical properties, and crystallinity, enabling PMD-PD as CIL material with excellent thickness-insensitive characteristics, while simultaneously improving device stability significantly. Furthermore, PMD-PD also exhibits good compatibility with various electrodes and active layers, offering solar cell efficiencies of up to 19.91% and 19.29% with Ag and Cu cathodes, respectively. More importantly, the application of PMD-PD can improve the performance of semi-transparent OSCs without losing transmittance, thereby drastically enhancing the light utilization efficiency to 4.04% with an ultrathin, low-cost Cu cathode, that competes with leading optical modulation-free semitransparent OSCs with expensive Ag cathodes. This work opens a pathway to realize transparent and conductive interlayers by strategic molecular design, leading to highly efficient, stable, and cost-effective OSCs suitable for diverse applications.

You, Zuhao↗
DOE OSTI2025

Incident beam optics optimization for the single crystal neutron diffractometer Pioneer with a polarized beam option

Pioneer, a next-generation single-crystal neutron diffractometer, is under development for Oak Ridge National Laboratory’s Second Target Station. Designed to address a wide range of scientific questions, Pioneer will deliver homogeneous neutron beams with customizable size and divergence and provide a polarized beam option. This article introduces its incident beam optics, highlighting the optimization methodology and the simulated performance. Pioneer will utilize a modified elliptical-straight guide for neutron transport and deploy slit packages and insertable apertures to control beam size and divergence. The optimized guide geometry matches the optimal-and-full-sample-illumination condition, and the beam control system effectively filters out unwanted neutrons while preserving the desired ones. In addition, we have found that polygon-approximated guides provide satisfactory transport efficiency and beam homogeneity, eliminating the need for truly curved guides. Further, to enhance neutronics performance and reduce cost, the coatings of supermirror elements are individually optimized to the lowest half-integer m-values that are sufficient to deliver the desired neutrons. After evaluating polarizing V-cavities and 3 He spin filters over the default polarized wavelength band of 1.2–5.5 Å, we selected a translatable multichannel polarizing V-cavity as the incident beam polarizer. Strategically placed at a location where the beam divergence is low and a large in-guide gap has negligible impact on transport efficiency, the optimized V-cavity achieves an average P 2 T of ~35%.

47 OTHER INSTRUMENTATION↗
DOE OSTI2020

A semi-supervised machine learning detector for physics events in tokamak discharges

Databases of physics events have been used in various fusion research applications, including the development of scaling laws and disruption avoidance algorithms, yet they can be time-consuming and tedious to construct. This paper presents a novel application of the label spreading semi-supervised learning algorithm to accelerate this process by detecting distinct events in a large dataset of discharges, given few manually labeled examples. A high detection accuracy (> 85%) for H-L back transitions and initially rotating locked modes is demonstrated on a dataset of hundreds of discharges from DIII-D with manually identified events for which only 3 discharges are initially labeled by the user. Lower yet reasonable performance (~75%) is also demonstrated for the core radiative collapse, an event with a much lower prevalence in the dataset. Additionally, analysis of the performance sensitivity indicates that the same set of algorithmic parameters is optimal for each event. Furthermore, this suggests that the method can be applied to detect a variety of other events not included in this paper, given that the event is well described by a set of 0D signals robustly available on many discharges. Procedures for analysis of new events are demonstrated, showing automatic event detection with increasing fidelity as the user strategically adds manually labeled examples. Detections on Alcator C-Mod and EAST are also shown, demonstrating the potential for this to be used on a multi-tokamak dataset.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2021

Strategic Petroleum Reserve Cavern Leaching Monitoring CY20

The U.S. Strategic Petroleum Reserve is a crude oil storage system run by the U.S. Department of Energy. The reserve consists of 60 active storage caverns spread across four sites in Louisiana and Texas, near the Gulf of Mexico. Beginning in 2016, the SPR began executing U.S. congressionally mandated oil sales. The configuration of the reserve, with a total capacity of greater than 700 MMB, requires raw water to be used instead of saturated brine for oil withdrawals such as for sales. All sales will produce leaching within the caverns used for oil delivery. Twenty-five caverns had a combined total of over 39 MMB of water injected in CY 20 as part of the Exchange for Storage program; oil was withdrawn in the same manner as for congressionally mandated sales. Leaching effects were monitored in these caverns to understand how the oil withdrawals may impact the long-term integrity of the caverns. While frequent sonars are the best way to monitor changes in cavern shape, they can be resource intensive for the number of caverns involved in sales and exchanges. An intermediate option is to model the leaching effects and see if any concerning features develop. The leaching effects were modeled here using the Sandia Solution Mining Code (SANSMIC) . The results indicate that leaching induced features are not of concern in the majority of the caverns, 19 of 25. Six caverns, BH-107, BH-113, BH-114, BM-4, BM-106, and WH-114 have features that may grow with additional leaching and should be monitored as leaching continues in those caverns. Ten caverns had post sale sonars that were compared with SANSMIC results. SANSMIC was able to capture the leaching well , particularly the formation of shelves and flares. A deviation in the SANSMIC and sonar cavern shapes was observed near the cavern floor in caverns with significant floor rise, a process not captured by SANSMIC. These results suggest SANSMIC is a useful tool for monitoring changes in cavern shape due to leaching effects related to sales and exchanges.

02 PETROLEUM↗
NASA NTRS2005

Initial Development of a Metric to Describe the Level of Safety Associated with Piloting an Aircraft with Synthetic Vision Systems (SVS) Displays

Synthetic Vision Systems (SVS) displays provide pilots with a continuous view of terrain combined with integrated guidance symbology in an effort to increase situation awareness (SA) and decrease workload during operations in Instrument Meteorological Conditions (IMC). It is hypothesized that SVS displays can replicate the safety and operational flexibility of flight in Visual Meteorological Conditions (VMC), regardless of actual out-the-window (OTW) visibility or time of day. Significant progress has been made towards evolving SVS displays as well as demonstrating their ability to increase SA compared to conventional avionics in a variety of conditions. While a substantial amount of data has been accumulated demonstrating the capabilities of SVS displays, the ability of SVS to replicate the safety and operational flexibility of VMC flight performance in all visibility conditions is unknown to any specific degree. In order to more fully quantify the relationship of flight operations in IMC with SVS displays to conventional operations conducted in VMC, a fundamental comparison to current day general aviation (GA) flight instruments was warranted. Such a comparison could begin to establish the extent to which SVS display concepts are capable of maintaining an "equivalent level of safety" with the round dials they could one day replace, for both current and future operations. A combination of subjective and objective data measures were used to quantify the relationship between selected components of safety that are associated with flying an approach. Four information display methods ranging from a "round dials" baseline through a fully integrated SVS package that includes terrain, pathway based guidance, and a strategic navigation display, were investigated in this high fidelity simulation experiment. In addition, a broad spectrum of pilots, representative of the GA population, were employed for testing in an attempt to enable greater application of the results and determine if "equivalent levels of safety" are achievable through the incorporation of SVS technology regardless of a pilot's flight experience.

Bartolone, Anthony P.↗