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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 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Ground and flight calibration assessment of HiRAP accelerometer data from missions STS-35 and STS-40

A method of removing non-aerodynamic signals and calibrating the High Resolution Accelerometer Package (HiRAP) flight data was developed and is discussed for Shuttle Orbiter missions STS-35 and STS-40. These two mission data sets were analyzed using ground (dynamic) calibration data and flight calibrations using a flight calibration technique that was developed and refined over the HiRAP operational lifetime. This technique evolved early in the flight program, since it was recognized that ground calibration factors are insufficient to determine absolute low acceleration levels. The application of flight calibration factors to the data sets from these missions produced calibrated acceleration levels within an accuracy of less than plus or minus 1.5 micro-g of zero during a time in the flight when the acceleration level was known to be less than 1 micro-g. This analysis further confirms the theory that flight calibrations are required in order to obtain the absolute measurement of low-frequency, low-acceleration flight signals.

Blanchard, Robert C.↗
NASA NTRS1989

A spaceborne optical interferometer: The JPL CSI mission focus

The JPL Control Structure Interaction (CSI) program is part of the larger NASA-wide CSI program. Within this larger context, the JPL CSI program will emphasize technology for systems that demand micron or sub-micron level control, so-called Micro-Precision Controlled Structures (u-PCS). The development of such technology will make it practical to fly missions with large optical or large precision antenna systems. In keeping with the focused nature of the desired technology, the JPL approach is to identify a focus mission, develop the focus mission CSI system design to a preliminary level, and then use this design to drive out requirements for CSI technology development in the design and analysis, ground test bed, and flight experiment areas.

Laskin, R. A.↗
NASA NTRS1993

A feasibility study of a microgravity enhancement system for Space Station Freedom

The current low frequency microgravity requirements for Space Station Freedom (SSF) call for a level of less than 1 micro-g over 50 percent of all the laboratory racks for continuous periods of 30 days for at least 180 days per year. While this requirement is attainable for some of the laboratory modules for the Permanently Manned Configuration (PMC), it can not be met for the Man-Tended Configuration (MTC). In addition, many experiments would prefer even lower acceleration levels. To improve the microgravity environment, the Microgravity Enhancement System (MESYS) will apply a continuous thrust to SSF, to negate the disturbing gravity gradient and drag forces. The MESYS consists of a sensor, throttle-able thrusters and a control system. Both a proof mass system and accelerometer were evaluated for use as the sensor. The net result of the MESYS will be to shift the microgravity contours from the center of mass to a chosen location. Results indicate the MESYS is not feasible for MTC since it will require 5,073 kg of hydrazine fuel and 7,660 watts of power for 30 days of operation during average atmospheric conditions. For PMC, the MESYS is much more practical since only 4,008 kg of fuel and 5,640 watts of power are required.

Diamond, Preston S.↗
NASA NTRS2002

Experimental Evaluation of White Light Fabry-Perot Interferometry Fiber-Optic Strain Gages when Measuring Small Strains

An experimental study was conducted to evaluate whether fiber optic strain gages (FOSG) are "better" sensors than typical foil gages. A particularly attractive feature of FOSG was their specified resolution of 0.01% of full-scale (0.1 micro strain for 1000 micro strain full-scale). This feature would make FOSG practical tank level sensors, by measuring very small strains on the support structure of a tank. A specific application in mind was to measure liquid oxygen tank level, with support beams that were predicted to contract approximately 11 micro strain as the tank goes from empty to full. Among various fiber optic technologies currently available, Fabry-Perot Interferometry using white light was selected. This technology exhibits highly desirable feature such as absolute strain measurement, linearity over its full-scale, and temperature compensation. However, experiment results suggest that the resolution is 0.8 micro strain, at best, calibration from one sensor to another can be off by 2.4 - 11.2%, and that temperature compensation is not fully predictable, with errors of up to 3.5 micro strain over an 11C range. Hence, when compared with classic foil gages, FOSG possess less accuracy, similar resolution and repeatability (precision), and superior linearity over their entire operating range. They are immune to EMI and their signals suffer minimal degradation over long distances. It is also expected that drift with time will be minimal in FOSG whereas the gage factor of foil sensors changes over time when exposed to varying environmental conditions. In conclusion, FOSG are "better" than foil gages as long as the application allows calibration of individual units as installed for operation.

St.Cyr, William↗
NASA NTRS1999

CO2 Accumulation in the Non-Conformal Helmet of the NASA Launch and Entry Suit During Simulated Unaided Egress

The Launch and Entry Suit (LES) has been worn by astronauts since 1988 for Space Shuttle launch and landing. Previous work indicated that carbon dioxide (CO2) accumulation in the LES non-conformal helmet might be high during locomotion while wearing the LES. The purpose of this study was to characterize the inspired CO2%, metabolic requirements, and egress performance during a simulation of an unaided egress from the Space Shuttle in healthy male subjects wearing the LES and walking on a treadmill. With the helmet visor closed, 12 male subjects completed a 6-min seated prebreathe with 100% O2 followed by a 2-min stand and 5 min of walking at 1.56 m/sec (5.6 km/h, 3.5 mph) as a simulation of unaided egress. All subjects walked with four different G-suit pressures (0.0, 0.5, 1.0, 1.5 psi). After a 10-min recovery, subjects walked 5 min with the same G-suit pressure and helmet visor open for the measurement of metabolic rate (VO2). When G-suit inflation levels were 1.0 or 1.5 psi, only 4 of our 12 healthy, non-micro-gravity exposed subjects completed the unaided egress. Inspired CO2 levels greater than 4% were routinely observed during walking. The metabolic cost at the 1.5 psi G-suit inflation was over 135% of the metabolic cost at 0.0 psi inflation. During unaided egress, G-suit inflation pressures of 1.0 (required inflation for missions greater than 11 days) and 1.5 psi resulted in elevated CO2 in the LES helmet and increased metabolic cost of walking, either of which could impact unaided egress by returning space flight crews.

Greenisen, M. C.↗
NASA NTRS1989

Dynamics and control of the tether elevator/crawler system

This paper investigates the dynamics and acceleration levels of a new tethered system for micro- and variable-gravity applications. The system consists of two platforms tethered on opposite sides to the Space Station. A fourth platform, the elevator, is placed in between the Space Station and the upper platform. Variable-g levels on board the elevator are obtained by moving this facility along the upper tether, while microgravity experiments are carried out on board the Space Station. By controlling the length of the lower tether the position of the system center of mass can be maintained on board the Space Station despite variations of the system's distribution of mass. The paper illustrates the mathematical model, the environmental perturbations and the control techniques which have been adopted for the simulation and control of the system dynamics. Two sets of results from two different simulation runs are shown. The first set shows the system dynamics and the acceleration spectra on board the Space Station and the elevator during station-keeping. The second set of results demonstrates the capability of the elevator to attain a preselected g-level.

Lorenzini, E. C.↗
DOE OSTI2023

Optical Properties of Individual Tar Balls in the Free Troposphere

Tar balls are brown carbonaceous particles, highly viscous, spherical, amorphous, and light absorbing. They are believed to form in biomass burning smoke plumes during transport in the troposphere. Tar balls are believed to have a significant impact on the Earth’s radiative balance, but due to poorly characterized optical properties, this impact is highly uncertain. Here, we investigate the chemical composition and optical properties of individual tar balls transported in the free troposphere to the Climate Observatory “Ottavio Vittori” on Mt. Cimone, Italy (2165 meters above sea level) using multi-modal micro-spectroscopy. Our results show that tar balls contributed 50% of carbonaceous particles by number in the size range from 0.25 to 1.8 µm. Of those tar balls, 16% were inhomogeneously mixed with other constituents. Using electron energy loss spectroscopy, we retrieved the complex refractive index from 200 to 1200 nm for both inhomogeneously and homogeneously mixed tar balls. We found no significant difference in the average refractive index of inhomogeneously and homogenously mixed tar balls (1.40 - 0.03i, and 1.36 - 0.03i at 550 nm, respectively). Furthermore, we estimated the top of the atmosphere radiative forcing using the Santa Barbara DISORT Atmospheric Radiative Transfer model (SBDART) and found that a layer of only tar balls with an optical depth of 0.1 above vegetation would exert a positive radiative forcing ranging from 2.8 Wm-2 (on a clear sky day) to 9.5 Wm-2 (when clouds are below the aerosol layer). In conclusion, understanding the optical properties of tar balls can help reduce uncertainties associated with the contribution of biomass-burning aerosol in current climate models.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Connecting Hindered Transport in Porous Media across Length Scales: From Single-Pore to Macroscopic

Hindered mass transport is widely observed in various porous media, including filtration membranes and porous rocks. However, there is no universal model capable of predicting transport in porous media due to the heterogeneity of porous structures and the complexity of the underlying microscopic mechanisms, including electrostatic and hydrodynamic effects. Here, we used a highly ordered porous medium (i.e. a silica inverse opal film) as a model system to directly explore the effects of geometric parameters (i.e. pore size, pore throat size and tracer particle size) and microscopic interaction parameters (e.g. controlled by ionic strength) on nanoparticle transport in porous environments using three-dimensional single-particle tracking. We found a linear scaling relation between the macroscopic diffusion coefficient and microscopic diffusion behaviors and a combination of parameters associated with microscopic features and phenomena, including both geometric effects and particle-level interactions. The proportionality coefficient relating micro and macro behaviors was complex and related to the connectivity of the matrix and pore-size variation, which could lead to tortuous diffusion pathways, hindering macroscopic transport. Furthermore, these findings provide important insights into nanoparticles and macromolecules transport in various porous media.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

3D printed Ni-Mn-Fe Bi-Functional Catalyst for Metal Air Batteries

Oxygen evolution catalyst with porous structures on the submillimeter and millimeter ranges have been shown to have high catalytic activity. Often, a limiting factor in the performance of a catalyst can be its specific surface area as this can limit the availability of active sites which encourage the desired reaction. As such, the inclusion of a hierarchical structure that include both meso-scale and nano-scale porosity can offer a means to greatly increase the performance of electrochemical catalysts. We have developed a method for manufacturing samples with such a hierarchical structure by combining techniques of direct ink writing (DIW), thermal sintering and free corrosion based dealloying. This allows us to prepare three-dimensionally structured samples with open-cell porosity at the macro-, micro- and nano-scales. Each level of porosity offers a different advantage to the overall functionality and applicability of this technology.

25 ENERGY STORAGE↗
NASA NTRS1991

An integrated eddy current detection and imaging system on a silicon chip

Eddy current probes have been used for many years for numerous sensing applications including crack detection in metals. However, these applications have traditionally used the eddy current effect in the form of a physically wound single or different probe pairs which of necessity must be made quite large compared to microelectronics dimensions. Also, the traditional wound probe can only take a point reading, although that point might include tens of individual cracks or crack arrays; thus, conventional eddy current probes are beset by two major problems: (1) no detailed information can be obtained about the crack or crack array; and (2) for applications such as quality assurance, a vast amount of time must be taken to scan a complete surface. Laboratory efforts have been made to fabricate linear arrays of single turn probes in a thick film format on a ceramic substrate as well as in a flexible cable format; however, such efforts inherently suffer from relatively large size requirements as well as sensitivity issues. Preliminary efforts to fully extend eddy current probing from a point or single dimensional level to a two dimensional micro-eddy current format on a silicon chip, which might overcome all of the above problems, are presented.

Henderson, H. Thurman↗
NASA NTRS1993

A feasibility study of a microgravity enhancement system for Space Station Freedom

The current low frequency microgravity requirements for Space Station Freedom (SSF) call for a level of less than 1 micro-g over 50 percent of all the laboratory racks for continuous periods of 30 days for at least 180 days per year. While this requirement is attainable for some of the laboratory modules for the Permanently Manned Configuration (PMC), it cannot be met for the Man-Tended Configuration (MTC). To improve the microgravity conditions in the laboratory modules, the Microgravity Enhancement System (MESYS) will apply a continuous thrust to SSF, to negate the disturbing gravity gradient and drag forces. The MESYS consists of a sensor, continuous throttle-able thrusters, and a control system. Both a proof mass system and nano-g accelerometer were evaluated for use as the sensor. The net result of the MESYS will be to shift the microgravity contours from the center of mass to a chosen location. Results indicate the MESYS is not feasible for the MTC since it will require 5073 kg of hydrazine fuel and 7660 watts of electrical power for 30 days of operation during average atmospheric conditions. For the PMC, the MESYS is much more practical, since only 4008 kg of fuel and 5640 watts of electrical power will be required for 30 days of operation during average atmospheric conditions.

Diamond, Preston S.↗
NASA NTRS2003

Mesoscale Computational Investigation of Shocked Heterogeneous Materials with Application to Large Impact Craters

The propagation of shock waves through target materials is strongly influenced by the presence of small-scale structure, fractures, physical and chemical heterogeneities. Pre-existing fractures often create craters that appear square in outline (e.g. Meteor Crater). Reverberations behind the shock from the presence of physical heterogeneity have been proposed as a mechanism for transient weakening of target materials. Pre-existing fractures can also affect melt generation. In this study, we are attempting to bridge the gap in numerical modeling between the micro-scale and the continuum, the so-called meso-scale. To accomplish this, we are developing a methodology to be used in the shock physics hydrocode (CTH) using Monte-Carlo-type methods to investigate the shock properties of heterogeneous materials. By comparing the results of numerical experiments at the micro-scale with experimental results and by using statistical techniques to evaluate the performance of simple constitutive models, we hope to embed the effect of physical heterogeneity into the field variables (pressure, stress, density, velocity) allowing us to directly imprint the effects of micro-scale heterogeneity at the continuum level without incurring high computational cost.

Crawford, D. A.↗
NASA NTRS2016

Advancing Small Satellite Electronics Heritage for Microfluidic Biological Experiments

DLR's Eu:CROPIS (Euglena and Combined Regenerative Organic-Food Production in Space) mission, launching in 2017, will carry multiple biological payloads into a sun-synchronous orbit, including NASA Ames' PowerCell experiment. PowerCell will attempt to characterize the viability of synthetic biology at micro-g, Lunar, and Martian gravity levels. PowerCell experiment requirements demand an electronic system similar to previous microfluidic biology payloads, but with an expanded feature set. As such, the system was based on PharmaSat (Diaz-Aguado et al. 2009), a previous successful biology payload from NASA Ames, and improved upon. Newer, more miniaturized electronics allow for greater capability with a lower part count and smaller size. Two identical PowerCell enclosures will fly. Each enclosure contains two separate and identical experiments with a 48-segment optical density measurement system, grow light system, microfluidic system for nutrient delivery and waste flushing, plus thermal control and environmental sensing/housekeeping including temperature, pressure, humidity, and acceleration. Electronics consist of a single Master PCB that interfaces to the spacecraft bus and regulates power and communication, plus LED, Detector, and Valve Manifold PCBs for each experiment. To facilitate ease of reuse on future missions, experiment electronics were designed to be compatible with a standard 3U small sat form factor and power bus, or to interface with a Master power/comm PCB for use in a larger satellite as in the case of PowerCell's flight on Eu:CROPIS.

biology↗
DOE OSTI2023

Milone eTape Liquid Level Sensor Laboratory Calibration with a Commercial 12.2 cm HS-Flume and 3D Printed 4 cm Micro-HS-Flumes

The NGEE Arctic Rainfall Simulator (NARS) is a variable intensity rainfall simulator (RFS) with a frame design based on the Humphry et al. (2002) RFS and a water delivery system based on the Walnut Gulch (Paige et al., 2004) RFS. The NARS uses an aluminum frame that is fully deconstructable for transportation to field locations and a water system that enables variable rain intensity. Prior to field deployment, H-flume discharge and the corresponding Milone eTape Liquid Level Sensor (eTape) resistance values were measured in the laboratory so that discharge measurements from the NGEE Arctic Rainfall Simulator could be automated. eTape resistance was measured with increasing fluid heights for the full range of the eTape to calculate sensor detection limits and resolution. The eTape was calibrated to both a commercially available 12.2 cm HS-flume and a 3D printed 4 cm Micro-HS-flume. This data package contains two .csv files, one for the eTape calibration and the other for the flume calibrations, and two .stl files to 3D print the 4 cm Micro-HS-Flume design with a 1 cm x 3.6 cm stilling well opening. The .stl files can be opened in most 3D printing or CAD programs/software. Two .kml files of the laboratory location and broader area where testing was conducted are also included in this data package.The Next-Generation Ecosystem Experiments: Arctic (NGEE Arctic), was a research effort to reduce uncertainty in Earth System Models by developing a predictive understanding of carbon-rich Arctic ecosystems and feedbacks to climate. NGEE Arctic was supported by the Department of Energy's Office of Biological and Environmental Research.The NGEE Arctic project had two field research sites: 1) located within the Arctic polygonal tundra coastal region on the Barrow Environmental Observatory (BEO) and the North Slope near Utqiagvik (Barrow), Alaska and 2) multiple areas on the discontinuous permafrost region of the Seward Peninsula north of Nome, Alaska.Through observations, experiments, and synthesis with existing datasets, NGEE Arctic provided an enhanced knowledge base for multi-scale modeling and contributed to improved process representation at global pan-Arctic scales within the Department of Energy's Earth system Model (the Energy Exascale Earth System Model, or E3SM), and specifically within the E3SM Land Model component (ELM).

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

The Power Reclamation of Utilizing Micro-Hydro Turbines in the Aeration Basins of Wastewater Treatment Plants

Upgrading the aeration basin technology can improve the oxygen transfer efficiency (OTE), while keeping the energy consumption at its minimum level. Therefore, this paper introduces a new idea of installing micro-propeller turbines in the aeration basin of a wastewater treatment plant (WWTP) to extract power from the high-velocity location in the water column. This extracted power can be used to operate a mixer at the top of the membrane to induce the mixing in that region, which will drive the less oxygenated wastewater into the water column. The rest of the extracted power will rotate microturbine rotors for electric power generation. By applying the proposed microturbines to the 13 audited facilities, it was demonstrated to achieve a gross annual energy-savings of 3,836.9 MWh, a gross annual cost-saving of $260,497, and total CO 2 emissions that would be reduced by 2,714 metric tons/year. Generally, the addition of the proposed microturbines can save up to 15.7% of the annual plant electricity consumption (1.3–12.8% of the plant annual electricity bills).

13 HYDRO ENERGY↗
DOE OSTI2020

Adaptive simulations enable computational design of electron beam processing of nanomaterials with supersonic micro-jet precursor

Focused Electron Beam Induced Processing (FEBIP) is a powerful tool for the “direct-write” of nanomaterials with the possibility of atomistic control on suspended 2D material substrates. FEBIP capabilities have been significantly expanded by using a localized jet-based delivery of precursors, and especially when a thermally energized supersonic micro-jet enhances the delivery of mass flux along with controlling the far-from-equilibrium thermodynamic state of adsorbed adatoms. The possibilities of growing nanomaterials with “dialed-in” composition with ultra-high growth rates and aspect ratios up to 100:1 have been demonstrated using the supersonic micro-jet-FEBIP. Bringing this scientific discovery to the level of maturity required for practical applications in additive nanomanufacturing requires simulation tools that are capable of capturing the complex flow physics of micro-jet-substrate interactions that bridge a wide range of flow regimes from the high-density gas micro-jet expanding into the vacuum environment of FEBIP. To address this significant computational challenge, a new approach has been developed and described in this work for a multiscale adaptive DSMC (Direct Simulation Monte Carlo) algorithm to predict the micro-jet gas dynamics in an FEBIP environment, spanning the full range of flow regimes from low Knudsen (Kn) number O(0.01) continuum flow to high Kn of O(10) for the molecular flow within a unified computational framework. Here, the fundamental principles of the adaptive DSMC algorithm are described, its viability as a DSMC technique is demonstrated, and computational improvements for the benchmark cases are discussed in the context of advancing 3D nanofabrication with FEBIP. Ultimately, combining the first principle simulations via adaptive DSMC with the complementary experimental data will enable the creation of the powerful CAD tools for in silico design and optimal operation of micro-jet-FEBIP.

36 MATERIALS SCIENCE↗
NASA NTRS1995

Effect of irradiance, sucrose, and CO2 concentration on the growth of potato (Solanum tuberosum L.) in vitro

Growth measurements were taken of potato plantlets (Solanum tuberosum L.) cvs. Norland (NL), Denali (DN), and Kennebec (KN), grown in vitro. Studies were conducted in a growth chamber, with nodal explants grown for 21 days on Murashige and Skoog salts with either 0, 1, 2, or 3% sucrose and capped with loose-fitted Magenta 2-way caps that allowed approximately 2.25 air exchanges/hour. Plantlets were exposed to either 100 or 300 micro mol/sq m/s photosynthetic photon flux (PPF), and the growth chamber was maintained at either 400 or 4000 micro mol/mol CO2. Regardless of PPF, all cvs. that were grown at 4000 micro mol/mol CO2 showed significant increases in total plantlet dry weight (TDW) and shoot length (SL) when sucrose was omitted from the media, indicating an autotrophic response. At 400 micro mol/mol CO2, all cvs. showed an increase in TDW and SL with increasing sucrose under both PPF levels. Within any sucrose treatment, the highest TDW for all cvs. resulted from 300 micro mol/sq m/s PPF and 4000 micro mol/mol CO2 At 4000 micro mol/mol CO2, TDW showed no further increase with sucrose levels above 1% for cvs. NL and DN at both PPF levels, suggesting that sucrose levels greater than 1% may hinder growth when CO2 enrichment is used.

Yorio, Neil C.↗
NASA NTRS1984

Micro-elastohydrodynamic Lubrication

Conventional elastohydrodynamics, which is based on assumption of smooth surfaces, is reviewed briefly to show its insufficiency for explaining the failure processes in these contacts. For conditions approaching failure, lubrication breakdown occurs locally at asperity contacts where the lubrication behavior is controlled by micro-elastohydrodynamic lubrication (Micro-EHL). Description is given to the film formation mechanisms in micro-EHL conjunctions. An assessment is made to the level of film thickness due to normal approach and sliding of a single asperity and due to asperlty-asperlty collision between two asperities; Possible influence of the micro-EHL to incipient scuffing failure, surface crack propagation and wear are discussed.

H S Cheng↗