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At least 325 records · Page 18
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Assessments of Physiology And Cognition in Hybrid-reality Environments (APACHE) – Physical Workload Approximation

The Human Physiology, Performance, Protection & Operations Laboratory (H-3PO) at NASA Johnson Space Center (JSC) is developing a hybrid reality exploration surface analog, “Assessments of Physiology and Cognition in Hybrid-reality Environments” (APACHE). The goal of APACHE is to create a planetary extravehicular activity (EVA) simulation environment that provides a representative physical and cognitive workload approximation using a combination of virtual reality (VR), physical reality, and hybrid reality (HR) techniques. To develop and characterize the physical workload approximation within the APACHE environment, a two-part approach was implemented. In part 1, baseline physical work load during ambulation within APACHE was evaluated and compared with that in other planetary EVA analog environments and with existing data sets from Apollo planetary EVAs and reduced gravity testing of prototype planetary spacesuits. For this evaluation, 10 subjects were asked to ambulate in three surface analog environments: a passive treadmill in APACHE, natural terrain in an outdoor field environment, and a standard motorized treadmill. Subjects’ heart rate and metabolic rate (VO2/VCO2) were measured and compared among the different test conditions and existing data sets. Gait parameters were also collected to compare with suited mechanics and to understand the role of gait kinematics in physical workload. In part 2, the aim is to evaluate the addition of a custom weighted body suit to the aforementioned surface analog environments and the ability to titrate the suit configuration to provide the best possible physical workload approximation for simulation of lunar and Martian EVAs.

Alex Baughman↗
NASA NTRSDate not supplied

Assessments of Physiology And Cognition in Hybrid-reality Environments (APACHE) – Physical Workload Approximation

The Human Physiology, Performance, Protection & Operations Laboratory (H-3PO) at NASA Johnson Space Center (JSC) is developing a hybrid reality exploration surface analog, “Assessments of Physiology And Cognition in Hybrid-reality Environments” (APACHE). The goal of APACHE is to create a planetary extravehicular activity (EVA) simulation environment that provides a representative physical and cognitive workload approximation using a combination of virtual reality (VR), physical reality, and hybrid reality (HR) techniques. To develop and characterize the physical workload approximation within the APACHE environment, a two-part approach was implemented. In part 1, baseline physical workload during ambulation within APACHE was evaluated and compared with that in other planetary EVA analog environments and with existing data sets from Apollo planetary EVAs and reduced gravity testing of prototype planetary spacesuits. For this evaluation, 10 subjects were asked to ambulate in three surface analog environments: a passive treadmill in APACHE, natural terrain in an outdoor field environment, and a standard motorized treadmill. Subjects’ heart rate and metabolic rate (VO2/VCO2)were measured and compared among the different test conditions and existing data sets. Gait parameters were also collected to compare with suited mechanics and to understand the role of gait kinematics in physical workload. In part 2, the aim is to evaluate the addition of a custom weighted body suit to the aforementioned surface analog environments and the ability to titrate the suit configuration to provide the best possible physical workload approximation for simulation of lunar and Martian EVAs.

Alexander J Baughman↗
DOE OSTI2023

Modeling, testing, and mitigation of electromagnetic pulse on PV systems

Electromagnetic Pulse (EMP) poses a significant threat to the normal operation of power systems, especially with the increasing penetration of renewable energy. Without adequate protection, EMP can severely damage equipment or result in circuit breakdowns or short circuits. Solar photovoltaic (PV) facilities are particularly susceptible to EMP since PV systems are outdoors and exposed to EMP radiation. To assess and mitigate this threat, this paper summarizes various models and tests used to study the effects of EMP on PV systems, assesses the nature of the threat, and identifies measures to mitigate it. The paper provides a comprehensive review by categorizing analytical methods based on their pros and cons, introducing and describing EMP-related events, and providing a taxonomy of analytical methods for studying EMP. This paper compares the processes of modeling, testing, and mitigating EMP at both the component and system levels of PV systems. Furthermore, it also presents a case study that reveals the vulnerability of solar inverters to EMP using the pulse current injection method. Finally, the paper discusses some of the remaining challenges that should be considered in future solar PV system design and deployment.

14 SOLAR ENERGY↗
DOE OSTI2023

Microalgae Hydrothermal Liquefaction and Biocrude Upgrading: 2022 State of Technology

A preliminary techno-economic analysis (TEA) was developed for the fiscal year (FY) 2022 state of technology (SOT) assessment to evaluate the benefits and risks of using demonstrated, high-productivity algae strains for fuels generation, including sustainable aviation fuel (SAF). In 2022, the marine algal strain, Picochlorum celeri, which demonstrated the highest outdoor biomass productivities reported to date in the DOE-funded open-pond raceway testbed at the Arizona Center for Algae Technology and Innovation (AzCATI), was tested for continuous hydrothermal liquefaction (HTL) processing at PNNL. HTL testing results demonstrated a biocrude yield of 0.33 g/g algae on an ash-free dry weight (AFDW) basis from P. celeri. The hydrotreatment testing of the HTL biocrude from P. celeri was also conducted to investigate the production of jet fuel from marine algal biomass. To the best of our knowledge, this is the first report of jet fuel production from autotrophically grown marine algal biomass. The current hydrotreating testing demonstrated approximately 22.7 wt% of the hydrotreated oil within the typical boiling-point range of jet fuel (150–250 °C). Initial testing of the jet fuel cut (JFC) showed that the physical properties under investigation were within typical ranges for petroleum-based jet fuels. The experimental work of this study closes the gap between outdoor algae cultivation and algae conversion to critical transportation fuels using the same algae strain for both cultivation and conversion testing. The continuous HTL and the upgrading testing described herein demonstrate the potential of producing sustainable aviation fuel (SAF) from algae cultivated in open-pond systems using the primary inputs of sunlight and carbon dioxide.

09 BIOMASS FUELS↗
NASA NTRS1985

Rotorcraft research testing in the National Full-Scale Aerodynamics Complex at NASA Ames Research Center

The unique capabilities of the National Full-Scale Aerodynamics Complex (NFAC) for testing rotorcraft systems are described. The test facilities include the 40- by 80-Foot Wind Tunnel, the 80- by 120-Foot Wind Tunnel, and the Outdoor Aerodynamic Research Facility. The Ames 7- by 10-Foot Subsonic Wind Tunnel is also used in support of the rotor research programs conducted in the NFAC. Detailed descriptions of each of the facilities, with an emphasis on helicopter rotor test capability, are presented. The special purpose rotor test equipment used in conducting helicopter research is reviewed. Test rigs to operate full-scale helicopter main rotors, helicopter tail rotors, and tilting prop-rotors are available, as well as full-scale and small-scale rotor systems for use in various research programs. The test procedures used in conducting rotor experiments are discussed together with representative data obtained from previous test programs. Specific examples are given for rotor performance, loads, acoustics, system interactions, dynamic and aeroelastic stability, and advanced technology and prototype demonstration models.

Warmbrodt, W.↗
NASA NTRS2014

Testing Astronaut-Controlled Telerobotic Operation of Rovers From the International Space Station as a Precursor to Lunar Missions

Missions to Earth-Moon libration points can advance capabilities for human exploration and provide unique opportunities to advance scientific knowledge. For example, NASA’s Orion spacecraft, currently under development, could serve as a platform from which astronauts would explore the lunar farside using robots that they remotely operate from a libration point. During Summer 2013, we conducted initial testing of this “surface telerobotics” concept of operations using the International Space Station (ISS) as a proxy for Orion orbiting the Moon. Over the course of three test sessions, Expedition 36 astronauts Chris Cassidy, Luca Parmitano, and Karen Nyberg on the ISS remotely operated NASA’s “K10” planetary rover in an outdoor terrain located at the NASA Ames Research Center (ARC). In this paper, we discuss the motivation for Earth-Moon libration point missions, describe the surface telerobotics tests performed to date, and outline directions for future ISS testing.

Fong, Terrence↗
DOE OSTI2024

Survival and behavior of Mojave desert tortoises head-started with and without outdoor rearing

Mojave desert tortoise (Gopherus agassizii) populations in some regions have declined by >50% since 2004, prompting the need for more research on ways to recover populations. One possible recovery tool is head-starting (i.e., the act of protecting and raising juvenile tortoises to sizes that increase survival upon release); however, head-starting can have high start-up and maintenance costs that can limit its feasibility. Strategies that reduce cost and rearing duration may foster broader and more effective use. We released and radio-tracked 60 juvenile tortoises in the Mojave National Preserve in California, USA, that had been reared under 2 treatments: those reared 1 year indoors after hatching, then 1 year outdoors (combo) and those reared just 1 year indoors (indoor-only). We tested whether indoor-only rearing alone could be a more efficient means of producing robust head-started tortoises. We examined the behavior, movement, and survival of tortoises after release into the wild from 2020 to 2021 to determine whether these outcomes differed between husbandry treatments. Combo tortoises tended to perform settling behaviors (mean ± 1 SE days to building first burrow = 6.7 ± 0.8, entering dormancy = 23.3 ± 2.1, and emerging from dormancy = 189.6 ± 4.4) earlier than indoor-only tortoises (7.4 ± 0.9, 31.5 ± 2.6, and 193.9 ± 5.9, respectively), but this difference was not significant, suggesting the rearing method did not greatly alter settling behavior. Indoor-only tortoises dispersed at least twice as far from their release site (156.2 ± 26.3 m compared with 77.3 ± 20.6 m for combo tortoises), had larger mean use areas (3.7 ± 0.1 ha compared with 2.8 ± 0.3 ha for combo tortoises for 95% Brownian bridge movement model estimates), and greater variability in their movements than combo tortoises (daily average step length post-emergence: 4.3 ± 0.2 m compared with 2.8 ± 0.1 m for combo tortoises). Despite differences in their movements, indoor-only and combo tortoises had similar survival rates over the study, 51% versus 42%, respectively, during a period of extreme drought in 2021. The similarity in survival between groups gives head-starting practitioners freedom in their rearing methods. The indoor-only group had lower site fidelity, which should be considered when this is an undesirable trait for released tortoises.

60 APPLIED LIFE SCIENCES↗
NASA NTRS1974

Solar energy recorder

A serious obstacle to the large-scale terrestrial application of solar energy lies in the scarcity of reliable data on the amount of solar energy at candidate converter sites. This paper describes a system designed to monitor and record, automatically, the values of the direct and total (sun and sky) solar radiation which would be seen by either tracking or fixed-type solar converters. A further pressing need addressed by the system is the means for efficiency testing and evaluation of solar cells, solar collectors and solar concentrator systems, under outdoor exposure to natural sunlight and weather conditions for extended periods. The design was accomplished in support of the Marshall Space Flight Center, NASA, where design concepts and materials for large-scale terrestrial solar energy converters are currently being evaluated.

Lollar, R. B.↗
NASA NTRS1991

LT-23: The feedback vibrating capacitor fieldmeter

A redesign effort was undertaken starting in the fall of 1988 to replace the Models 1019A and 1019B fieldmeter probes resulting in greatly improved performance. Extensive testing was conducted to confirm performance of the new design and to evaluate outdoor atmospheric applicability. The following subjects are discussed: theory of operation, design improvements, performance, proper use, and applications of the new intrinsically safe design.

Vosteen, James R.↗
DOE OSTI2022

Test and Evaluation of Solar Foil Directly Mounted on the Ground (Final Report)

HyET Solar (HyET), established in 2012, is a small business developing a thin-film silicon solar photovoltaic (PV) product called "Power Foil" that can be mounted directly on the constructed earthen dykes. HyET's goals are for low-cost, efficient, generation of PV electricity at utility scale. HyET has requested assistance from the National Renewable Energy Laboratory (NREL) to evaluate the performance of the Power Foil product in several outdoor environments, with a particular focus on 1) heat effects on efficiency and 2) heat and UV effects on reliability and durability. NREL has been working on PV module testing at laboratory scale for more than 40 years, and has the equipment and facilities required to provide the PV material testing required.

14 SOLAR ENERGY↗
NASA NTRS1979

Solar simulator test facility

Discusses facility constructed at Marshall Space Flight Center to evaluate performance of solar energy collectors under simulated outdoor conditions. Facility simulates sunfall properties such as radiation intensity, spectrum, collimation, uniformity, and direction.

Humphries, W. R.↗
DOE OSTI2020

High-Throughput Optical Mapping for Accelerated Stress Testing of PV Module Materials

The study will provide guidance towards the design and application of larger and/or outdoor-use intended instruments. Measurement capability will be benchmarked against existing specimens, examined in a round-robin study using conventional spectrophotometer instruments. Data acquisition and storage will be integrated into the DuraMAT DataHub network along with data visualization tool, facilitating sharing of information.

14 SOLAR ENERGY↗
NASA NTRS2005

Research on Subjective Response to Simulated Sonic Booms at NASA Langley Research Center

Over the past 15 years, NASA Langley Research Center has conducted many tests investigating subjective response to simulated sonic booms. Most tests have used the Sonic Boom Booth, an airtight concrete booth fitted with loudspeakers that play synthesized sonic booms pre-processed to compensate for the response of the booth/loudspeaker system. Tests using the Booth have included investigations of shaped booms, booms with simulated ground reflections, recorded booms, outdoor and indoor booms, booms with differing loudness for bow and tail shocks, and comparisons of aircraft flyover recordings with sonic booms. Another study used loudspeakers placed inside people s houses, so that they could experience the booms while in their own homes. This study investigated the reactions of people to different numbers of booms heard within a 24-hour period. The most recent Booth test used predicted boom shapes from candidate low-boom aircraft. At present, a test to compare the Booth with boom simulators constructed by Gulfstream Aerospace Corporation and Lockheed Martin Aeronautics Company is underway. The Lockheed simulator is an airtight booth similar to the Langley booth; the Gulfstream booth uses a traveling wave method to create the booms. Comparison of "realism" as well as loudness and other descriptors is to be studied.

Sullivan, Brenda M.↗
DOE OSTI2025

Occupant-Centric Demand Response for Thermostatically-Controlled Home Loads

Efficiently managing energy usage to balance supply and demand on the electric grid is crucial, especially with the widespread deployment of distributed variable renewable electricity generation. This paper introduces two duty-cycle control methods for heating systems, adjusting thermostat setpoints to limit and shift electricity demand. The control approaches employ innovative techniques, such as adaptive duty cycling, to prioritize household thermal comfort while reducing peak demand. These control methods can respond to signals from the electric grid, including demand targets and time-of-use tariffs, and were tested physically on an electric furnace and heat pump in a test home during winter conditions in 2021 and 2022. The results are given as average demand reductions and energy use impacts with respect to the average indoor-outdoor temperature difference during the control period. For heat pumps, demand limiting control reduced power by 18.5% and 23.3% for indoor-outdoor temperature differences of 30°F and 40°F. Preheating-based demand shifting achieved reductions of 34.8% and 33.2% for the same temperature differences. Electric furnace tests showed demand reductions of 33.8% and 25.3% for demand limiting, and 56.1% and 45.7% for preheating-based demand shifting. These findings highlight the potential for innovative control methods to enhance grid efficiency and reduce energy consumption.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
NASA NTRS1994

Experimental studies of loudness and annoyance response to sonic booms

The purpose of this paper is to summarize the most recent sonic boom laboratory studies performed at NASA-LaRC using the Sonic Boom Simulator. The first used synthesized idealized outdoor boom shapes which were filtered to represent booms heard inside a house. The test explored the efficacy of various metrics in assessing both loudness and annoyance responses to these booms. The second test investigated the effects of adding single reflections to idealized boom signatures, and the third compared booms recorded from real aircraft with idealized boom signatures to determine if subjects rated the real booms differently. In these studies, as in previous studies performed at NASA-LaRC, there was a continuing effort to evaluate metrics for predicting the subjective effects of sonic booms.

Sullivan, Brenda M.↗
DOE OSTI2025

Hydronic Shell: An Affordable Solution for Multifamily Deep Energy Retrofit

Approximately 42% of multi-family buildings in the United States have do not have insulation as required by the building codes. Envelope retrofits of these buildings are needed to improve their thermal performance, provide thermal resilience, and enable a pathway to electrification of space heating systems. Hydronic shell (HS) is a retrofit technique where a stud wall layer is added to a masonry wall along with a convective coil and a fan coil unit fitted in the façade cavity which can provide both heating and cooling to the space. The HS system serves a dual purpose of 1) retrofitting the building envelope and 2) retrofitting the HVAC system and enabling electrification of space heating. The electrification of space heating is possible from the installation of a combination of hydronic system/fan coil unit system which uses a central heat pump as a source of heating water in the cavity between the existing wall and retrofit insulation layer. This study evaluates the performance of the HS system at varying outdoor conditions mimicked by a climate chamber and hot water supply temperature from a water bath. During the ramp-up period, the indoor chamber temperature could be increased from 66 ºF to 69.5 ºF within an hour using heating water at 120 ºF when the outdoor chamber temperature was at 0 ºF. When the indoor chamber temperature was maintained within a deadband, variation in cavity air temperature was mostly influenced by the duration when water was flowing through the cavity convector. It was seen from the testing that the hydronic system alone without use of fan in the system is able to maintain the space temperature at coldest outdoor condition used in the experiment (0 ºF) even at lowest hot water supply temperature chosen (90 ºF). During the ramp-down period, the fastest decline in temperature took 6.4 hours from temperature to drop from 69.6 ºF to 66 ºF which shows tremendous potential of thermal resilience and peak load shifting.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
NASA NTRS1977

Accelerated/abbreviated test methods of the low-cost silicon solar array project. Study 4, task 3: Encapsulation

Methods of accelerated and abbreviated testing were developed and applied to solar cell encapsulants. These encapsulants must provide protection for as long as 20 years outdoors at different locations within the United States. Consequently, encapsulants were exposed for increasing periods of time to the inherent climatic variables of temperature, humidity, and solar flux. Property changes in the encapsulants were observed. The goal was to predict long term behavior of encapsulants based upon experimental data obtained over relatively short test periods.

Kolyer, J. M.↗
NASA NTRSDate not supplied

Comparing Two Weather-Robust Microphone Configurations for Outdoor Measurements

This paper discusses comparisons made between two ground-based outdoor microphone configurations. The first is known as the Compact Outdoor Unit for Ground-based Acoustical Recordings (COUGAR) and consists of an inverted microphone placed above a convex circular plate and covered by a large dome windscreen. The second configuration is the COUGARxt, where the “xt” simultaneously refers to an extra thick windscreen and an extra thin ground plate. COUGAR and COUGARxt were subjected to laboratory testing where their responses to sound were recorded at several different elevation and azimuthal angles. At almost all shown elevation angles, both configurations recorded levels that were within ±3 dB of a baseline measurement between 50 Hz – 20 kHz. At all shown azimuthal angles and over the same frequency range, both recorded levels within ±2 dB of the levels reported at an azimuthal angle of 0°, with COUGARxt having less variation than COUGAR. The configurations were also subjected to wind noise testing, where COUGARxt demonstrated superior wind noise rejection at low frequencies. The conclusion is that both configurations are suitable for outdoor acoustical measurements and that COUGARxt is the superior configuration, especially when measuring low-frequency noise.

sonic boom↗