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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 289 records · Page 16

All sources NASA NTRS DOE OSTI

NASA NTRSDate not supplied

Energy-Optimized Path Planning for Uas in Varying Winds Via Reinforcement Learning

In this paper we propose a reinforcement learning (RL) algorithm for path planning of Unmanned Aviation Vehicles (UAVs) under varying wind conditions. Solutions to UAV path planning problems are becoming increasingly necessary as autonomous UAVs continue to enter commercial and government spaces. Path-planning is inherently challenging, as UAVs need to account for dynamically changing flying conditions such as weather, obstacle or no-fly zones, degraded vehicle health, and off-nominal battery power consumption. Machine learning methods such as reinforcement learning (RL) have the potential to revolutionize how vehicles navigate in such uncertain environments. In this study, we compute UAV trajectories from a pre-determined starting position to a target cell within a 7X7 grid environment by optimizing parameters for mission assurance and safety limits in addition to the energy consumption and operation time. The UAV navigates the grid by taking actions to move in any of the eight cardinal and inter-cardinal directions, under constant thrust profile. The resultant UAV state is sampled from a probability distribution which accounts for the UAV’s action, local wind velocity, and the presence of obstacles or boundaries. As the unmanned airspace gets more complex due to multiple vehicles and environmental uncertainties, trade-offs between energy consumption, operation time, risk tolerance, and mission assurance need to be made. Our Markov Decision Process (MDP) environment model can capture any combination of these in the optimization objective, making it novel compared to other work in the field.

trajectory planning↗

NASA NTRS1982

Stratospheric aerosols - Observation and theory

Important chemical and physical roles of aerosols are discussed, and properties of stratospheric aerosols as revealed by experimental data are described. In situ measurements obtained by mechanical collection and scattered-light detection yield the overall size distribution of the aerosols, and analyses of preserved aerosol precursor gases by wet chemical, cryogenic and spectroscopic techniques indicate the photochemical sources of particle mass. Aerosol chemical reactions including those of gaseous precursors, those in aqueous solution, and those on particle surfaces are discussed, in addition to aerosol microphysical processes such as nucleation, condensation/evaporation, coagulation and sedimentation. Models of aerosols incorporating such chemical and physical processes are presented, and simulations are shown to agree with measurements. Estimates are presented for the potential aerosol changes due to emission of particles and gases by aerospace operations and industrial consumption of fossil fuels, and it is demonstrated that although the climatic effects of existing levels of stratospheric aerosol pollution are negligible, potential increases in those levels might pose a future threat.

Turco, R. P.↗

NASA NTRSDate not supplied

Food Acceptability, Menu Fatigue, and Aversion During the Sirius-21 Analog Mission

Spaceflight food systems are closed systems, meaning they are restricted to the variety and quantity of food launched within resource limitations of the mission. The acceptability of the food system has been linked to caloric intake and associated nutritional benefits. ISS crew members receive substantial personal food preferences (around 25% of their total intake) but have noted in debriefs that they would prefer more food variety and preference for the length of the missions and they tire of certain foods over six months. Limits on variety and personal preference are expected to increase as missions become further from Earth. It is possible that menu fatigue leads to decreases in acceptability and increased aversion to available foods that may contribute to the body mass loss often experienced by spaceflight crews. However, the impact of repeat food consumption on acceptability has not yet been systematically investigated across potential spaceflight food systems. Limited variety and crew preferences within food categories may have more severe physical and behavioral health and performance consequences as mission duration increases. Characterizing the relationship between food acceptability and mission duration will contribute to defining requirements for an acceptable food system that will support crew health and performance on long duration missions. This study evaluated acceptability of the food system used in the SIRIUS-21 8-month mission in Moscow, Russia. To capture in situ scoring of repeat consumption experiences, we administered a weekly food acceptability questionnaire to all 5 crewmembers throughout the mission. Crewmembers scored foods they consumed at 3 meals every 6 days on a 9-point hedonic scale and provided open-ended feedback regarding food context, attributes, and the meal. The sequence was intended to capture all days in the 7-day menu cycle. The repetition was intended to target repeat food ratings that may provide insight into onset of menu fatigue where they might stop eating some foods or limit their choices to their favorites. Every 30 days crewmembers completed two additional surveys to characterize the food system, any changes to the food system, and their experience with the food system. Data collection is complete. Data are currently being assessed by descriptive statistics and visualizations of the ratings over time. The primary goal is to look for trends in the trajectories of ratings of the food items over time – both within and between individuals – to determine if there are substantial decreases in acceptability across all foods, or within specific food categories (e.g., vegetables). The number of times a particular item is scored provides some information on the frequency of consumption (preference), and the overall number of unique items can give a measure of overall variety. We will assess whether individuals were more likely to have more observations on food items that are rated higher, and whether those who rated foods higher had more or less overall variety. Since the data are composed of longitudinal subjective ratings, repeated measures techniques will be used to quantify trends over time and how these may relate to preference and variety. We will assess how these trends relate to their characterization of and experience with the SIRIUS-21 food system. We will also provide content analysis of any additional feedback collected on the open-ended questions and debrief interviews.

Grace L. Douglas↗

DOE OSTI2020

Near-Zero Power MOF-Based Sensors for NO 2 Detection

Detection and capture of toxic nitrogen oxides (NO x ) is important for emissions control of exhaust gases and general public health. The ability to directly electrically detect trace (0.5–5 ppm) NO 2 by a metal–organic framework (MOF)-74-based sensor at relatively low temperatures (50 °C) is demonstrated via changes in electrical properties of M-MOF-74, M = Co, Mg, Ni. The magnitude of the change is ordered Ni > Co > Mg and explained by each variant's NO 2 adsorption capacity and specific chemical interaction. Ni-MOF-74 provides the highest sensitivity to NO 2 ; a 725× decrease in resistance at 5 ppm NO2 and detection limit <0.5 ppm, levels relevant for industry and public health. Furthermore, the Ni-MOF-74-based sensor is selective to NO 2 over N 2 , SO 2 , and air. Linking this fundamental research with future technologies, the high impedance of MOF-74 enables applications requiring a near-zero power sensor or dosimeter, with the active material drawing <15 pW for a macroscale device 35 mm 2 with 0.8 mg MOF-74. Finally, this represents a 10 4 –10 6 × decrease in power consumption compared to other MOF sensors and demonstrates the potential for MOFs as active components for long-lived, near-zero power chemical sensors in smart industrial systems and the internet of things.

47 OTHER INSTRUMENTATION↗

DOE OSTI2022

SEI formation mechanisms and Li + dissolution in lithium metal anodes: Impact of the electrolyte composition and the electrolyte-to-anode ratio

The lithium metal battery is one of today's most promising high-energy-density storage devices. Its full-scale implementation depends on solving operational and safety issues intrinsic to the Li metal high reactivity leading to uncontrolled electrolyte decomposition and uneven Li deposition. In this work, we study the spontaneous formation of the solid electrolyte interphase (SEI) upon contact of Li metal with the electrolyte and describe the heterogeneous SEI morphological features. Multiple electrolyte formulations based on lithium bis(fluorosulfonyl)imide (LiFSI), dimethoxyethane (DME), dimethyl carbonate (DMC), 1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE) and bis(2,2,2-trifluoroethyl) ether (BTFE) are used. Findings include the description of the SEI evolution from dispersed LiO, LiS, LiN, and LiF clusters to a continuous and compact inorganic phase in which the LiO and LiF content depend on the presence of fluorine diluents. Further, the role of the DME ether solvent helping the growth of a “wet-SEI” is compared to that of the highly unstable carbonate DMC, which decomposes into complex radical oligomers that might contribute to further electrolyte decomposition. The impact of the electrolyte-to-anode ratio on LiFSI decomposition is highlighted. Finally, we suggest the existence of a critical LiFSI concentration and electrolyte-to-anode ratio that could potentially balance the rate of electrolyte depletion and lithium consumption.

25 ENERGY STORAGE↗

DOE OSTI2022

Methane Catalytic Pyrolysis by Microwave and Thermal Heating over Carbon Nanotube-Supported Catalysts: Productivity, Kinetics, and Energy Efficiency

Methane catalytic pyrolysis, which is the reaction to produce hydrogen and carbon without emitting CO 2 , represents an approach for decarbonization using natural gas as an energy resource. In this work, the endothermic pyrolysis reaction was carried out under two heating scenarios: convective thermal heating and microwave-driven irradiative heating. The pyrolysis reaction was conducted at 550-600 °C over carbon nanotube-supported Ni-Pd and Ni-Cu catalysts. On both catalysts, an enhanced methane conversion rate was observed under microwave irradiation. The enhanced catalytic activity was hypothetically caused by the presence of free electrons in the carbon atoms within CNT that enabled the CNT support to absorb microwave energy effectively and to be heated efficiently by microwave. The microwave catalytic pyrolysis has shown improvement in kinetics, where the apparent activation energy dropped from 45.5 kJ/mol under conventional convective heating to 24.8 kJ/mol under microwave irradiation. When the methane conversion rate is increased by 37 %, the microwave power consumption only changed by 10.8 %. The research demonstrated the potential of transforming natural gas to clean hydrogen and value-added carbon in a more energy-efficient way. Process simulation and techno-economic analysis showed that potentially hydrogen minimum selling price of about $1 /kg H 2 could be achieved.

03 NATURAL GAS↗

DOE OSTI2021

Design and Optimization of the Direct Recycling of Spent Li-Ion Battery Cathode Materials

Direct regeneration of spent Li-ion batteries based on the hydrothermal relithiation of cathode materials is a promising next-generation recycling technology. In order to demonstrate the feasibility of this approach at a large scale, we systematically design and optimize the process parameters to minimize both energy and raw material costs. Specifically, the effects of regenerative processing parameters on the composition, structure, and electrochemical performance of the regenerated cathode materials are investigated via systematic characterization and testing. From this analysis, it was found that the raw material costs can be substantially reduced by either replacing the typically employed 4 M LiOH solution by a cost-effective mixture of 0.1 M LiOH and 3.9 M KOH or recycling of the concentrated 4 M LiOH for continuous relithiation processes. Finally, life cycle analysis suggests that this strategy results in reduced energy consumption and greenhouse gas emissions, leading to an increased potential revenue, particularly when compared with hydro- and pyrometallurgical recycling methods.

25 ENERGY STORAGE↗

DOE OSTI2024

Enabling the Electrification of Offshore Activities – Co-Demonstration of Next-Generation Autonomous Offshore Power System and Resident, Uncrewed Mobile and Static Assets at PacWave Wave Energy Test Site

Oceans cover two-thirds of the earth's surface and form the world's biggest and best – yet largely untapped – battery. Ocean waves have more energy density than other renewables, including wind, solar, and biomass, and have the potential to supply 4x the world's annual energy consumption (Masterson, 2022; Zic, 2020). In addition to the impact wave energy can have on decarbonizing and diversifying the electric grid, it offers a significant value proposition in the emerging blue economy sector (LiVecchi et al, 2019). The blue economy consists of industries operating offshore, including shipping, oil and gas, defense and security, aquaculture, and research. These industries require bringing people and energy on site to perform daily work, but current energy costs in the blue economy are extremely high. Here, the prevailing processes are complex, including shore dependencies and fuel transportation logistics. Few alternatives for reliable power generation exist, with the most prominent being high cost and high carbon emissions diesel generation. Because of this lack of affordable, reliable power, the trends of electrification, digitization, and automation that have led to substantial innovation and improvements in the terrestrial economy over the last two decades are slow to come to the blue economy.

16 TIDAL AND WAVE POWER↗

NASA NTRS1975

Fuel conservation possibilities for terminal area compatible aircraft

Design features and operational procedures are identified, which would reduce fuel consumption of future transport aircraft. The fuel-saving potential can be realized during the last decade of this century only if the necessary research and technology programs are implemented in the areas of composite primary structure, airfoil/wing design, and stability augmentation systems. The necessary individual R and T programs are defined. The sensitivity to fuel usage of several design parameters (wing geometry, cruise speed, propulsion) is investigated, and the results applied to a candidate 18, 140-kg (40,000-lb) payload, 5556-km (3000-nmi) transport design. Technical and economic comparisons are made with current commercial aircraft and other advanced designs.

Source record↗

NASA NTRS1982

Economic viability of photovoltaic power for development assistance applications

This paper briefly discusses the development assistance market and examines a number of specific photovoltaic (PV) development assistance field tests, including water pumping/grain grinding (Tangaye, Upper Volta), vaccine refrigerators slated for deployment in 24 countries, rural medical centers to be installed in Ecuador, Guyana, Kenya and Zimbabwe, and remote earth stations to be deployed in the near future. A comparison of levelized energy cost for diesel generators and PV systems covering a range of annual energy consumptions is also included. The analysis does not consider potential societal, environmental or political benefits associated with PV power. PV systems are shown to be competitive with diesel generators, based on life cycle cost considerations, assuming a system price of $20/W(peak), for applications having an annual energy demand of up to 6000 kilowatt-hours per year.

Bifano, W. J.↗

NASA NTRS1986

Plasma-Sprayed Coatings on Porous Surfaces

Need for combining benefits of duplex thermal-barrier coatings with film cooling on gas-turbine vanes and blades stimulated development of improved method for plasma spraying these coatings. Method reduces blocking of holes by plasma-sprayed material and at same time reduces base-metal oxidation during coating operation. Features provide potential for increased engine efficiency and power, reduced fuel consumption, use of less costly materials or construction procedures, and extended life and durability.

Leibert, C. H.↗

NASA NTRS2014

Investigation of Bio-Regenerative Life Support and Trash-to-Gas Experiment on a 4-Month Mars Simulation Mission

Future crewed missions to other planets or deep space locations will require regenerative Life Support Systems (LSS) as well as recycling processes for mission waste. Constant resupply of many commodity materials will not be a sustainable option for deep space missions, nor will stowing trash on board a vehicle or at a lunar or Martian outpost. The habitable volume will decline as the volume of waste increases. A complete regenerative environmentally controlled life support system (ECLSS) on an extra-terrestrial outpost will likely include physico-chemical and biological technologies, such as bioreactors and greenhouse modules. Physico-chemical LSS do not enable food production and bio-regenerative LSS are not stable enough to be used alone in space. Mission waste that cannot be recycled into the bio-regenerative ECLSS can include excess food, food packaging, clothing, tape, urine and fecal waste. This waste will be sent to a system for converting the trash into high value products. Two crew members on a 120 day Mars analog simulation, in collaboration with Kennedy Space Centers (KSC) Trash to Gas (TtG) project investigated a semi-closed loop system that treated non-edible biomass and other logistical waste for volume reduction and conversion into useful commodities. The purpose of this study is to show how plant growth affects the amount of resources required by the habitat and how spent plant material can be recycled. Real-time data was sent to the reactor at KSC in Florida for replicating the analog mission waste for laboratory operation. This paper discusses the 120 day mission plant growth activity, logistical and plant waste management, power and water consumption effects of the plant and logistical waste, and potential energy conversion techniques using KSCs TtG technology.

Trash-to-Gas↗

NASA NTRS2014

Investigation of Bio-Regenerative Life Support and Trash-To-Gas Experiment on a 4 Month Mars Simulation Mission

Future crewed missions to other planets or deep space locations will require regenerative Life Support Systems (LSS) as well as recycling processes for mission waste. Constant resupply of many commodity materials will not be a sustainable option for deep space missions, nor will storing trash on board a vehicle or at a lunar or Martian outpost. The habitable volume will decline as the volume of waste increases. A complete regenerative environmentally controlled life support system (ECLSS) on an extra-terrestrial outpost will likely include physico-chemical and biological technologies, such as bioreactors and greenhouse modules. Physico-chemical LSS do not enable food production and bio-regenerative LSS are not stable enough to be used alone in space. Mission waste that cannot be recycled into the bio-regenerative ECLSS can include excess food, food packaging, clothing, tape, urine and fecal waste. This waste will be sent to a system for converting the trash into the high value products. Two crew members on a 120 day Mars analog simulation, in collaboration with Kennedy Space Centers (KSC) Trash to Gas (TtG) project investigated a semi-closed loop system that treated non-edible biomass and other logistical waste for volume reduction and conversion into useful commodities. The purposes of this study are to show the how plant growth affects the amount of resources required by the habitat and how spent plant material can be recycled. Real-time data was sent to the reactor at KSC in Florida for replicating the analog mission waste for laboratory operation. This paper discusses the 120 day mission plant growth activity, logistical and plant waste management, power and water consumption effects of the plant and logistical waste, and potential energy conversion techniques using KSCs TtG reactor technology.

trash to gas↗

NASA NTRSDate not supplied

Maipo River Valley Agriculture: Determining Crop Coefficients Using Remote Sensing for the Maipo River Valley Basin in Chile

Agriculture is the primary use of water in the Maipo River basin of Central Chile, accounting for ~ 75% of the total demand. Assessment of irrigation needs for agricultural production has commonly relied on reference crop coefficients (Kc) derived from geographic and climatic conditions that differ from those of Chile. In partnership with the Centro de Información de Recursos Naturales (CIREN), this work focused on calculating site-specific crop coefficients tailored to crop production in the water-stressed Maipo River Valley. Two distinct approaches were implemented, each relying on remotely-sensed Earth observation datasets from NASA over consecutive growing seasons from 2019 to 2022. The first method estimated Kc values based on their linear relationship with the Normalized Difference Vegetation Index (NDVI) obtained from either Terra Moderate Resolution Imaging Spectroradiometer (MODIS) or Landsat 8 Operational Land Imager (OLI) surface reflectance. The second technique leveraged information from the ISS Ecosystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) by computing the ratio between actual crop evapotranspiration (ET) and potential evapotranspiration (PET). Both procedures showed promising results that can build on one another. The former approach best captured vegetation signals of annual crops while the latter appeared suited for perennials. Overall, this study provides a strong basis and novel way to accurately estimate Kc using remote sensing, with the potential for improved irrigation management and reduction in water consumption.

Benjamin Goffin↗

NASA NTRSDate not supplied

Determining Crop Coefficients Using Remote Sensing for the Maipo River Valley Basin in Chile

Agriculture is the primary use of water in the Maipo River Valley of Central Chile, accounting for ~ 75% of the total demand. Assessment of irrigation needs for agricultural production has commonly relied on reference crop coefficients (Kc) derived from geographic and climatic conditions that differ from those of Chile. This work focused on calculating site-specific Kc values tailored to crop production in the water-stressed Maipo River Valley over consecutive growing seasons from 2019 to 2022. Two distinct approaches were implemented, each relying on remotely-sensed NASA Earth observation datasets. The first method estimated Kc values based on the linear relationship with the Normalized Difference Vegetation Index (NDVI) obtained from either Terra Moderate Resolution Imaging Spectroradiometer (MODIS) or Landsat 8 Operational Land Imager (OLI) surface reflectance. The second technique leveraged information from the ISS Ecosystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) by computing the ratio between actual crop evapotranspiration and potential evapotranspiration. The former approach best captured vegetation signals of annual crops while the latter appeared best suited for perennials. Overall, this study provides a strong basis and novel way to accurately estimate Kc using remote sensing, with the potential for improved irrigation management and reduction in water consumption.

Rishudh Thadur↗

NASA NTRSDate not supplied

Strategies for Determining Safety of Fermented Foods Produced in Space

The BioNutrients experiments examine the feasibility of using microbially produced foods – yogurt, kefir, fermented food products– to supplement the current prepackaged food system to provide freshly synthesized nutrients and genetically engineered protein therapeutics to support crew health for sustainable and long duration crewed exploration. Safety of the products must be established as direct consumption of such products is a risk due to potential contamination with pathogenic organisms. Identifying pathogen contamination is particularly challenging as the fermenting cultures can mask the presence of contaminating organisms. Here we consider current methods of detecting coliforms, aerobic colonies, non-lactic acid bacteria, molds (yeasts), and specific pathogens including Staphylococcus aureus and salmonella. We also consider alternate and additional testing including sequencing and quantitative PCR. We investigate the use of the E-Nose developed by NASA Ames Research Center. This portable device senses volatile organic compounds in real time and can be trained to recognize “good” uncontaminated products from contaminated ones as a means of predicting food safety. Finally, we consider methods of in-flight pasteurization to increase safety and decrease overall microbial load of these products. This presentation will summarize testing status and outline the strategy that will be employed in the BioNutrients-3 ISS fermented foods experiment.

Natalie Ball↗

NASA NTRSDate not supplied

Strategies for Determining Safety of Fermented Foods Produced in Space

Food↗

NASA NTRS1982

Performance and operational economics estimates for a coal gasification combined-cycle cogeneration powerplant

A performance and operational economics analysis is presented for an integrated-gasifier, combined-cycle (IGCC) system to meet the steam and baseload electrical requirements. The effect of time variations in steam and electrial requirements is included. The amount and timing of electricity purchases from sales to the electric utility are determined. The resulting expenses for purchased electricity and revenues from electricity sales are estimated by using an assumed utility rate structure model. Cogeneration results for a range of potential IGCC cogeneration system sizes are compared with the fuel consumption and costs of natural gas and electricity to meet requirements without cogeneration. The results indicate that an IGCC cogeneration system could save about 10 percent of the total fuel energy presently required to supply steam and electrical requirements without cogeneration. Also for the assumed future fuel and electricity prices, an annual operating cost savings of 21 percent to 26 percent could be achieved with such a cogeneration system. An analysis of the effects of electricity price, fuel price, and system availability indicates that the IGCC cogeneration system has a good potential for economical operation over a wide range in these assumptions.

Nainiger, J. J.↗