Highly Vibrationally Excited OH in the Terrestrial Mesosphere: Key Rate Constants for OH(v = 9, 8) Removal by Atomic and Molecular Oxygen Required for TIMED/SABER Observationsdata.nasa.gov | Last Updated 2018-09-05T23:06:16.000Z
<p>SRI International proposes laboratory measurements of the rate constants for: 1) the total removal of OH(v = 9) and OH(v = 8) by O atoms and O2 molecules and 2) the single-quantum relaxation of OH(v = 9) to generate OH(v = 8) in collisions with O atoms and O2 molecules. The experiments will also determine the temperature dependence of these rate constants in the range 150-300 K, so that the rate constant data can be directly applicable to the mesospheric OH nightglow region. These measurements are critical for a reliable analysis of the OH(high v) Meinel band emission measurements of the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument aboard NASA’s Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite. Although the hydroxyl radical is a key player in the chemistry and energy balance of the middle terrestrial atmosphere and several studies have investigated energy transfer processes between OH(v) and atmospheric molecules, several gaps exist in our understanding of its interactions with oxygen atoms and molecules, the two most important atmospheric species responsible for OH(high v) collisional relaxation. None of the six aforementioned key rate constants has been measured at temperatures relevant to the mesosphere. Three of those rate constants have only been measured at room temperature and for the remaining three, i.e., the total removal rate constant for OH(v = 8) + O and the rate constants for OH(v = 9) + O2 and OH(v = 9) + O single-quantum relaxation to generate OH(v = 8), there have never been any laboratory measurements. We have developed laser-based experimental approaches to measure the vibrational level dependence of the collisional removal rate constants for collisions of OH(v) with atmospherically relevant colliders. Research in our laboratory has provided the first experimental measurements on the interaction of OH(v = 9) with O and N2 at room temperature. These experiments demonstrated that the total removal rate constant for OH(v = 9) + O at room temperature is significantly larger than those for removal by O2 and N2. A physical explanation of this rather unexpected result remained elusive for almost a decade. In a breakthrough development, our most recent studies provided the first laboratory demonstration of the existence of new rapid, multi-quantum vibrational-to-electronic relaxation pathways applicable to OH(high v) + O collisions. We plan to use a combination of laser-based experimental approaches we have previously developed in our laboratory to study the aforementioned critical six rate constants. SRI International is an ideally suitable setting to perform the proposed work given our history in the invention and design of experimental approaches to study these complex collisional energy transfer processes. Moreover, we will work with Dr. Martin Mlynczak, a member of the TIMED/SABER Team, who will oversee the implementation of our experimental results into the SABER data analysis and modeling. Accurate values of the deactivation rate of the high-v states of OH are necessary for proper interpretation of the SABER data from the TIMED satellite and their availability would be most beneficial as soon as practically possible given the advanced stage in the life cycle of NASA’s TIMED mission. In addition, these rate constant values are essential for computing the heating efficiency of the highly exothermic H + O3 reaction, a key factor included in photochemical models of the upper atmosphere. The proposed research fits well within the Laboratory Nuclear, Atomic and Plasma Physics (LNAPP) sub-element of the NASA Heliophysics Technology and Instrument Development for Science (H-TIDeS) Program because these results on photochemical kinetics and dynamics are needed in atmospheric models and address the goals of the Decadal Heliophysics Survey.</p>
- API data.nasa.gov | Last Updated 2018-07-19T22:08:26.000Z
Metron Aviation designs and develops an integrated methodology and supporting algorithms for estimating environmental impacts of increased traffic on the surface and in the terminal airspace, and extends beyond estimation to identify key causes and develop mitigation options. From previous work, we provide multi-dimensional impact calculation in terms of noise, emissions, and fuel usage, as well as measurement of these impacts with respect to both baseline and alternative future scenarios. In AMITIE we add the following capabilities critically important to design of the next-generation system within environmental constraints: Automated identification of scenario elements causing the principal environmental impacts; Automated generation of mitigation options; and Quantification of the benefits of the mitigation options. The specific technical objectives are: Integrated estimation/mitigation methodology that provides the basis for closing the feedback loop from environmental impacts to system design and development. Develop supporting algorithms that calculate the appropriate metrics, analyze them to identify major causes of impacts, and generate mitigation options that reduce the impacts. Develop a software prototype that implements the estimation, analysis, and mitigation algorithms. Exercise the prototype against test cases to demonstrate the feasibility and value of the approach
- API data.nasa.gov | Last Updated 2018-09-07T17:48:07.000Z
We will develop a 500-pixel array of quantum capacitance detectors which have 1) per-pixel noise equivalent power (NEP) below 3e-20 W/sqrt(Hz), 2) high absorption efficiency, and 3) sufficient speed of response to count individual mid-IR through far-IR photons at rates up to 10 kHz. The full array will be read out with a single microwave circuit using a suite of probe tones interacting with resonators. The sensitivity, speed, and MUXing are the key enabling requirements for moderate-resolution (R~500) zodi-limited spectroscopy on future cryogenic far-IR facilities such as the Origins Space Telescope (formerly Far-IR Surveyor) or a far-IR probe-class mission. The photon counting capability offers the potential for enhanced scientific performance for a) high-stability applications such as exoplanet spectroscopy and b) high-resolution direct-detection spectroscopy at the shot-noise limit. Our work builds on the success with few-pixel quantum capacitance demonstrations at 200 microns, but we require a dedicated multi-pixel readout architecture, absorber and backshort geometry adapted to shorter wavelengths (down to 30 microns with a goal of 6 for exoplanet photon counting), and demonstration of high yield (>75%) with an improved tunnel junction design and fabrication approach.
Understanding evolution of redox transduction through ferredoxins, iron-sulfur proteins that control energy flowdata.nasa.gov | Last Updated 2018-09-07T17:46:29.000Z
Iron-sulfur cluster containing ferredoxins (Fds) are ancient proteins found in all three branches of life that participate in diverse energy transduction pathways including those found within organisms that are most closely related to the first free-living ancestors of Bacteria and Archaea (methanogens, acetogens, and sulfur-reducing microbes). Many researchers in the Fe-S field propose that modern clostridial-type 4Fe-4S Fds arose through duplication, fusion, and mutation of smaller peptides that also coordinated Fe-S clusters and supported ancient energy transduction pathways. The biophysical properties of small bio-inspired peptides that coordinate Fe-S clusters have been widely studied in vitro and found to display redox potentials that are compatible with energy transduction pathways essential for life, such as sulfite reduction to sulfide. However, fossil-like peptides have not yet been assayed for their ability to support any energy transduction pathways within cells. It remains unclear which of the many possible Fe-S-binding peptides can fulfill the functions of modern Fds within living cells, and how the sequence (length, cysteine motifs), physical (stability, redox potential) and functional (binding selectivity) properties of active Fe-S-binding peptides differ from modern Fds that relay redox for diverse reactions within cells. We hypothesize that the best way to understand fossil-like Fe-S-binding peptides that supported ancient energy transduction pathways is to create libraries of fragmented Fds having various peptide lengths, use cellular growth selections to mine these libraries for peptides that are redox active in cells and capable of supporting energy transduction, and sequence those variants that are active within the context of the complex cellular milieu. By analyzing the sequence, structure, cofactors, redox potentials, and oligomeric states of peptides selected from these libraries, we propose to obtain direct evidence supporting a role for Fe-S-binding peptides in early evolution within cells and establish the characteristics of peptides that are capable of supporting a cellular energy transduction reaction. Our specific objectives are to: (i) identify modern Fds that support energy transduction processes within cells by assaying activities using simple bacterial growth selections, (ii) find minimal Fe-S-binding peptides that support energy transduction within cells by fragmenting Fds and selecting for active peptides, and (iii) determine if the Fe-S-binding peptides are less selective than natural Fds in their ability to support different energy transduction reactions. The results from the proposed studies will be relevant to the Exobiology program and its interest in understanding the Early Evolution of Life because this research will identify putative primordial peptides that are capable of serving as redox cofactors for energy transduction within cells, establish the minimal peptide features within Fds that are required to coordinate an Fe-S cluster and support energy transduction within cells, and elucidate the biochemical and biophysical properties of active Fe-S-binding peptides (e.g., Fe-S cluster type, oligomeric state, redox potentials, and binding selectivity). These studies will also yield multiple Fd-derived fragments and Fds that support sulfite reduction and allow comparison of the sequence-structure-redox properties of fossil-like peptides and modern Fds in the same context. Furthermore, these studies will yield evidence that Fe-S peptides could support biotic S isotope fractionation signatures observed in putative molecular fossils from the Archaean, provide a framework for future studies of electron transfer among ancestral proteins involved in early energetic processes and their evolution, and facilitate future analysis of prebiotic chemical reactions supported by Fe-S peptides and allow comparisons with pure minerals (e.g., pyrite) and modern Fds.
- API data.nasa.gov | Last Updated 2018-09-05T23:03:58.000Z
Proposal Summary: Astronauts traveling to Mars or other planetary surfaces will be exposed to low doses (up to 2 Gy) of high-energy radiation particles that compose galactic cosmic radiation (GCR). A growing body of literature documents a rapid acceleration of bone resorption activity and some suppression of bone-forming cells after exposure to even very low doses of space-relevant radiation. One of the key mechanisms proposed for these changes is an increase in pro-inflammatory cytokines like TNF-a. We already know that International Space Station (ISS) crew members consuming a diet rich in omega-3 Fatty acids (FAs) experience smaller reductions in bone mineral density over 6-month missions than do fellow astronauts consuming a diet low in these FAs. This project proposes to investigate the impact of consuming a diet high in omega-3 FAs on radiation-induced pro-inflammatory cytokines. Hence, this simple dietary intervention may provide a low-cost, low-risk means of countering the harmful effects of radiation on bone integrity. <p></p> A currently funded NASA Space Biology study based at Texas A&M (Principal Investigator (PI): Dr. Nancy Turner) will expose multiple cohorts of mice at Brookhaven National Laboratory’s NASA Space Radiation Laboratory (NSRL) facility to space relevant doses of high energy iron particles) over the next 12 months. Her project will determine the selective impact of radiation on radio-sensitive intestinal stem cells in two sets of animals: those consuming a corn oil-supplemented diet simulating the average American diet and those consuming a diet supplemented with fish oil, which elevates dramatically omega-3 FA intake. The PI’s current collaborations with Dr. Turner and our laboratories’ close proximity have enabled an unparalleled tissue sharing opportunity. <p></p> We propose to collect both long bones and serum from these animals to test our over-arching hypothesis: a diet high in omega-3 FAs will mitigate radiation-induced bone loss by reducing the generation of inflammatory cytokines in bone tissue. The study offers the possibility of comparing responses to 3 different space-relevant doses (0.1, 0.25, and 0.5 Gy) of 56Fe at 1 Gev/nucleon, along with a gamma reference group (0.25 to 2 Gy). Analyses of specimens collected at 12 hours post-exposure will focus on changes in pro-inflammatory cytokines in serum and in bone cells called osteocytes, which in turn signal to both bone-forming and bone-resorbing cells. The two later post-irradiation time points proposed (4 wk and 8 wk) will enable us to determine early and late effects on bone cell activity and bone structural integrity, important since the current data base on time course of bone alterations post-exposure is sparse. <p></p> Significance : Given that the expensive NSRL (NASA Space Radiation Laboratory) live animal experiments are already funded, this project can yield a wealth of new data important to minimizing fracture risk for exploration class missions at minimal extra cost to NASA. With this project we will generate a comprehensive assessment of the impact of 3 doses of high-energy iron particles on bone integrity, at 3 dose levels and at 3 time points post-irradiation. Comparisons with gamma-irradiated groups at comparable doses will allow for RBE (relative biological effectiveness) determinations; sham irradiated animals will be sacrificed at the same time points. After just one year, we will have proof-of-concept and feasibility testing completed for a high omega-3 FA diet as a countermeasure to radiation-induced bone loss, and interesting science data on the role of osteocytes in the pro-inflammatory response to radiation. Should it prove successful, this countermeasure is ready for immediate operational implementation, as omega-3 fatty acid-rich diets and/or supplements are available now to ISS crew. These data will also be relevant to clinical patients undergoing radiotherapy and patients wit
- API data.nasa.gov | Last Updated 2018-07-20T05:37:54.000Z
Development of High Frequency Excitation Devices for Noise Reduction, Phase I
Seed-Derived Second Harmonic source for in situ alignment and calibration of trace gas measurement instruments, Phase Idata.nasa.gov | Last Updated 2018-07-19T10:02:00.000Z
This SBIR Phase I effort will demonstrate the feasibility of developing a tunable, high-power, narrowband seed laser source integrated with a broadband, waveguide-based second harmonic generation (SHG) module to allow in situ alignment, component testing and calibration across the tuning range of fiber-based lidar systems for measuring atmospheric oxygen concentrations. The lidar is being developed as part of a dual-wavelength remote sensing system for high precision CO2 measurements. Active laser-based spectroscopic remote sensing can map changes in CO2 concentration over the entire globe. However, the measurement of CO2 concentration varies depending on properties such as humidity, temperature, and pressure. To remove these variables, measurement of a stable, well-mixed gas such as oxygen is required as well. Generation of a broadly tunable SHG source with integrated laser for downstream seeding will further this approach.
- API data.nasa.gov | Last Updated 2018-07-19T12:38:50.000Z
Future space exploration missions present significant new challenges to crew health care capabilities, particularly in the efficient utilization of on-board oxygen resources. The International Space Station and future exploration vehicles require a light weight, compact, portable oxygen concentrator technology (OCT) that can provide medical grade oxygen from the ambient cabin air. Current OCTs are heavy, bulky, have a narrow operating temperature range (ambient to 40 degree Celsius), and require 15 to 30 minutes start-up time to reach their full operating capacity. Lynntech's proposed electrochemical OCT solves these issues by operating the OCT with a cathode-air vapor feed, unlike conventional electrochemical OCTs which require a liquid water feed. This is possible due to the use of in-house developed proprietary nanocomposite proton exchange membrane and catalyst technologies. Cathode-air vapor feed operation eliminates the need for a bulky on-board water supply, significantly reduces the complexity of the balance-of-plant, and greatly increases the system efficiency. OCT will be a quarter the size and weight of conventional OCTs, be capable of instant start-up, and have a wide operating temperature range. Lynntech will develop a Phase II prototype that is capable of delivering 4 SLPM of 60% oxygen and deliver it to NASA for further testing.
Novel Methodology for the Rapid Acoustic Optimization of Supersonic Multi-Stream 3D Nozzles, Phase Idata.nasa.gov | Last Updated 2018-09-07T17:39:48.000Z
<p style="margin-left:0in; margin-right:0in">Current noise prediction methods are ill-suited for the design of future nozzle geometries as they are either too computationally expensive or do not contain the necessary physics to adequately predict noise from desired nozzle types. As such, there is a need for innovative technologies and methods for noise prediction to enable acoustic optimization of multi-stream, 3D nozzle to meet the noise goals for NASA’s N+2/N+3 aircraft. We propose to extend the Reynold Averaged Navier-Stokes (RANS) based models developed at University of California, Irvine, that have been shown to accurately predict noise for nozzles 3D, multi-stream nozzles. Our proposed method will allow for accurate and rapid prediction of acoustic emission on engineering workstation-class computers, enabling design engineers to perform acoustic optimization while preserving aerodynamic performance. Our competent team has over 60 years of combined experience in jet noise and has the expertise to ensure that an accurate RANS-based noise model is developed by the end of Phase II along with a working acoustic optimization tool that is usable by engineers and compatible with NASA’s design framework.</p>
- API data.nasa.gov | Last Updated 2018-07-19T20:46:46.000Z
The proposed SBIR Phase I & II programs will lead to the validation of a state-of-the-art Large Eddy Simulation (LES) model, coupled with a Ffowcs-Williams-Hawkings (FW-H) farfield acoustic solver, for supporting the development of advanced engine concepts, including innovative flow control strategies for attenuation of their jet noise emissions. The LES/FW-H model will be simultaneously validated against matched sets of flowfield and companion acoustic data acquired recently at NASA/GRC for round nozzles. The flowfield validation will include detailed comparisons against imagery, mean flow measurements and turbulence statistics. The end-to-end capability of the LES/FW-H noise prediction model will also be demonstrated by applying it to high aspect-ratio rectangular nozzle designs, proposed for testing at NASA GRC under the Fundamental Aeronautics Program. This critical validation will provide the foundation for proceeding to application of this innovative methodology in supporting the design and optimization of control concepts, e.g. chevrons, slot jets, fluidic chevrons, etc., as well as ultimately performing predictions of noise emissions from full-scale, realistic nozzles with complex exhaust flowpaths, airframe/propulsive jet interactions, etc.