ALBERT

Beschreibung: We compared reproductive fitness and early postnatal growth of Bobwhite (Colinus virginianus) and Japanese (Coturnix coturnix japonica) quail incubated and hatched during 2 G centrifugation. Fertilized Bobwhite and Japanese quail eggs were placed in portable incubators on the 8-ft International Space Station Test Bed (ISSTB) Centrifuge at NASA Ames Research Center. The quail eggs were incubated throughout hatching and reared until Postnatal day (P)4 at either 1.0, 1.2 or 2.0 G. Two days before hatching, candling revealed significantly greater numbers of viable Bobwhite than Japanese quail eggs at all g-loads. Bobwhite quail exhibited significantly better hatching success at all g-loads than did Japanese quail. Bobwhite hatchlings were sensitive to gravitational loading as evidenced by reduced postnatal body mass and length of 2 G hatchlings relative to 1 G control hatchlings. In contrast, mass and length of Japanese quail hatchlings were unaffected by 1.2 or 2 G exposure. Together, our findings provide evidence for superior viability and hatching success in Bobwhite quail relative to Japanese quail, coupled with greater sensitivity of postnatal body growth and development to 2 G loading. Bobwhite quail may be better suited than Japanese quail for scientific studies on space biology platforms.

Beschreibung: The static stress drop of an earthquake is an indicator of the stress state of a specific fault before rupture initiation. The stress state is primarily controlled by the ambient stress field, fault strength, fault complexity, and the presence of fluids. This study aims to investigate the spatio‐temporal distribution of static stress drop values of the 2016–2017 multi‐fault rupture seismic sequence in central Italy, which includes three earthquakes with Mw ≥ 5.9 (Amatrice, Visso, and Norcia earthquakes), and over 95,000 aftershocks (M 0.5–6.5). We estimate stress drop values using a circular crack model with corner frequency and seismic moment estimates from single‐spectra fitting, a cluster‐event method, and spectral‐ratio fitting. The temporal distribution of stress drop values shows an apparent increase of stress drop following a large earthquake (Mw ≥ 5.9). The spatial distribution shows comparably high stress drop values for early aftershocks surrounding the mainshock rupture area. High stress drop events correlate with fault complexity, such as fault intersections at depth and reactivated thrust fronts. We observe a constant stress drop for Mw ≥ ∼3, in contrast to previous studies. Instrument response and signal‐to‐noise bandwidth limitations likely govern the observed decrease in stress drop with decreasing magnitude for events with Mw ≤ 3. The spatio‐temporal distribution of stress drop values in a complex seismic sequence could support a more complete understanding of the earthquake rupture process and the evolution of seismic sequences. It could also highlight areas where stress loading is focused, which would have implications for short and intermediate term seismic hazard estimates.

Beschreibung: Plain Language Summary: The ongoing earthquake sequence that began in 2016 in central Italy has produced a significant physical imprint on the earth's surface from the rupture of the three largest events, and has changed the state of stress within the crust. The earthquakes release stored stress in some regions, which can be measured indirectly by the waveforms recorded on seismometers (seismograms), and increase stress in others. Here we analyze seismograms, including those of numerous small earthquakes, to estimate source properties such as the physical size of the rupture surface and the corresponding fault slip. Source properties relate to the amount of stress released by an earthquake and are relevant to learning about the fault rupture process and the redistribution of stress during the evolution of a seismic sequence. We use a combination of approaches to find that the occurrence of large earthquakes leads to a temporal increase of stress in the vicinity of the ruptured fault, and that high stress release correlates with places where faults intersect in the subsurface. Our findings provide a more comprehensive picture of the complex seismic sequence and highlight areas that could influence short and intermediate term seismic hazard estimates.

Beschreibung: Key Points: The AVN seismic sequence shows significant spatio‐temporal variations in stress drop values. Higher stress drop values correlate with increasing fault complexity and stress field heterogeneity. Instrument response and signal‐to‐noise limitations likely govern stress drop scaling for events with for M 〈 ∼3.

Beschreibung: Deutsche Forschungsgemeinschaft (DFG) http://dx.doi.org/10.13039/501100001659

Beschreibung: The upper‐ocean circulation of the tropical Atlantic is a complex superposition of thermohaline and wind‐driven flow components. The resulting zonally and vertically integrated upper‐ocean meridional flow is referred to as the upper branch of the Atlantic Meridional Overturning Circulation (AMOC)—a major component and potential tipping element of the global climate system. Here, we investigate the tropical part of the northward AMOC branch, that is, the return flow covering the upper 1,200 m, based on Argo data and repeated shipboard velocity measurements. The western boundary mean circulation at 11°S is realistically reproduced from high‐resolution Argo data showing a remarkably good representation of the volume transport of the return flow water mass layers when compared to results from direct velocity measurements along a repeated ship section. The AMOC return flow through the inner tropics (11°S–10°N) is found to be associated with a diapycnal upwelling of lower central water into the thermocline layer of ∼2 Sv. This is less than half the magnitude of previous estimates, likely due to improved horizontal resolution. The total AMOC return flow at 11°S and 10°N is derived to be similar in strength with 16–17 Sv. At 11°S, northward transport is concentrated at the western boundary, where the AMOC return flow enters the inner tropics at all vertical levels above 1,200 m. At 10°N, northward transport is observed both at the western boundary and in the interior predominantly in the surface and intermediate layer indicating recirculation and transformation of thermocline and lower central water within the inner tropics.

Beschreibung: Plain Language Summary: The Atlantic Meridional Overturning Circulation (AMOC) is one of the major components of the global climate system. In the upper 1,200 m, the northward branch of the AMOC transports large amounts of heat, salt, and biogeochemical tracers across the equator from the South Atlantic through the tropics to the North Atlantic. In this study, we show that a realistic reconstruction of the upper‐ocean circulation at the southern hemisphere western boundary—a bottleneck for the AMOC—is possible based on high‐resolution Argo float data, further enabling transport and pathway estimates for the upper and intermediate water mass layers of the inner tropical Atlantic (11°S–10°N). At 11°S, the northward AMOC branch is largely concentrated at the western boundary, whereas, at 10°N, it preferably exits the inner tropics through the western boundary, but also through the interior basin after recirculating in the equatorial current system. When crossing the inner tropics, the water masses forming the AMOC return flow change their characteristics and the associated upwelling of water into the subsurface layer is found here to be less than half as large as previously estimated, likely due to improved horizontal resolution.

Beschreibung: Key Points: Observed Atlantic western boundary mean transport of the upper 1,200 m at 11°S is realistically reproduced from high‐resolution Argo data. Diapycnal transport estimates from high‐resolution Argo data show upwelling of ∼2 Sv into the tropical Atlantic thermocline layer. By combining shipboard measurements with Argo data, we provide an overview of the individual water mass pathways within the Atlantic Meridional Overturning Circulation return flow.

Beschreibung: European Union Horizon H2020 (TRIATLAS)

Beschreibung: Bundesministerium fuer Bildung und Forschung (BANINO)

Beschreibung: https://agupubs.onlinelibrary.wiley.com/action/downloadSupplement?doi=10.1029%2F2021JC018115&file=2021JC018115-sup-0001-Supporting+Information+SI-S01.docx

Beschreibung: https://www.aoml.noaa.gov/phod/gdp/mean_velocity.php

Beschreibung: ftp://ftp-icdc.cen.uni-hamburg.de/EASYInit/ORA-S4/monthly_1x1/

Beschreibung: https://doi.pangaea.de/10.1594/PANGAEA.937809

Beschreibung: https://doi.org/10.5281/zenodo.5772272

Beschreibung: http://sio-argo.ucsd.edu/RG_Climatology.html

Beschreibung: Der Semail Ophiolith im Osten der arabischen Halbinsel ist einer der größten und am besten zugänglichen Ophiolithkomplexe der Welt. Um die Obduktion und die weiteren Prozesse, die bei seiner Entstehung eine Rolle gespielt haben, umfassend verstehen zu können, wird eine genaue Kenntnis seiner Struktur und der darunter liegenden Kruste benötigt. Während das Material des Ophiolithen selbst, sowie die obere Kruste bereits in mehreren Studien eingehend untersucht wurde, fehlen vor allem in der unteren Kruste Informationen über ihren Aufbau und dort vorherrschende Dichteverteilungen. Ein vorhandenes 2D Modell der Kruste stützt sich auf Informationen aus 2D Seismik, Bohrlöchern und Reciever Funktionen. Kombiniert mit geologischen Informationen liefert dieses Modell detaillierte Schichtungen und Dichtewerte bis in 15 km Tiefe und ist konsistent zur dort oberflächlich gemessenen Bougueranomalie. Es enthält allerdings nur wenige Informationen zur Geometrie der Unterkruste und der Krusten-Mantel-Grenze, welche nun basierend auf einer neuen seismischen S-Wellen-Tomographie ergänzt werden. Zur Anpassung des modifizierten Modells an die Bougueranomalie, wurde anhand der Geschwindigkeitsverteilung in der seismischen Tomographie die Dichteverteilung der unteren Kruste abgeschätzt, so dass das Modell konsistent zu den vorhandenen Beobachtungswerten ist. Neben diesem 2D Modell bietet das neue 3D-Vs-Modell die Möglichkeit, laterale Variationen in der Bouguerschwere im gesamten Omangebirge genauer zu untersuchen.

Beschreibung: poster

Beschreibung: The ability to monitor air contaminants in the shuttle and the International Space Station is important to ensure the health and safety of astronauts, and equipment integrity. Three specific space applications have been identified that would benefit from a chemical monitor: (a) organic contaminants in space cabin air; (b) hypergolic propellant contaminants in the shuttle airlock; (c) pre-combustion signature vapors from electrical fires. NASA at Kennedy Space Center (KSC) is assessing several commercial and developing electronic noses (E-noses) for these applications. A short series of tests identified those E-noses that exhibited sufficient sensitivity to the vapors of interest. Only two E-noses exhibited sufficient sensitivity for hypergolic fuels at the required levels, while several commercial E-noses showed sufficient sensitivity of common organic vapors. These E-noses were subjected to further tests to assess their ability to identify vapors. Development and testing of E-nose models using vendor supplied software packages correctly identified vapors with an accuracy of 70-90%. In-house software improvements increased the identification rates between 90 and 100%. Further software enhancements are under development. Details on the experimental setup, test protocols, and results on E-nose performance are presented in this paper along with special emphasis on specific software enhancements. c2003 Elsevier Science B.V. All rights reserved.

Beschreibung: Currently Mars missions can collect more data than can be returned. Future rovers of increased mission lifetime will benefit from onboard autonomous data processing systems to guide the selection, measurement and return of scientifically important data. One approach is to train a neural net to recognize spectral reflectance characteristics of minerals of interest. We have developed a carbonate detector using a neural net algorithm trained on 10,000 synthetic Vis/NIR (350-2500 nm) spectra. The detector was able to correctly identify carbonates in the spectra of 30 carbonate and noncarbonate field samples with 100% success. However, Martian dust coatings strongly affect the spectral characteristics of surface rocks potentially masking the underlying substrate rock. In this experiment, we measure Vis/NIR spectra of calcite coated with different thicknesses of palagonite dust and evaluate the performance of the carbonate detector.

Beschreibung: Many papers have been published concerning the analysis of visual texture and yet, very few application domains use texture for image classification. A possible reason for this low transfer of the technology is the lack of experience and testing in real-world imagery. In this paper, we assess the performance of texture-based classification methods on a number of real-world images relevant to autonomous navigation on cross-country terrain and to autonomous geology. Texture analysis will form part of the closed loop that allows a robotic system to navigate autonomously. We have implemented two different classifiers on features extracted by Gabor filter banks. The first classifier models feature distributions for each texture class using a mixture of Gaussians. Classification is performed using Maximum Likelihood. The second classifier represents local statistics using marginal histograms of the features over a region centered on the pixel to be classified. We measure system performance by comparison to ground truth image labels.

Beschreibung: The Mars Exploration Rover Spirit recently set a record for the furthest distance traveled in a single sol on Mars. Future planetary exploration missions are expected to use even longer drives to position rovers in areas of high scientific interest. This increase provides the potential for a large rise in the number of new science collection opportunities as the rover traverses the Martian surface. In this paper, we describe the OASIS system, which provides autonomous capabilities for dynamically identifying and pursuing these science opportunities during longrange traverses. OASIS uses machine learning and planning and scheduling techniques to address this goal. Machine learning techniques are applied to analyze data as it is collected and quickly determine new science gods and priorities on these goals. Planning and scheduling techniques are used to alter the behavior of the rover so that new science measurements can be performed while still obeying resource and other mission constraints. We will introduce OASIS and describe how planning and scheduling algorithms support opportunistic science.

Beschreibung: Studies of blowing snow over Antarctica have been limited greatly by the remoteness and harsh conditions of the region. Space-based observations are also of lesser value than elsewhere, given the similarities between ice clouds and snow-covered surfaces, both at infrared and visible wavelengths. It is only in recent years that routine ground-based observation programs have acquired sufficient data to overcome the gap in our understanding of surface blowing snow. In this paper, observations of blowing snow from visual observers' records as well as ground-based spectral and lidar programs at South Pole station are analyzed to obtain the first climatology of blowing snow over the Antarctic plateau. Occurrence frequencies, correlation with wind direction and speed, typical layer heights, as well as optical depths are determined. Blowing snow is seen in roughly one third of the visual observations and occurs under a narrow range of wind directions. The near-surface layers typically a few hundred meters thick emit radiances similar to those from thin clouds. Because blowing snow remains close to the surface and is frequently present, it will produce small biases in space-borne altimetry; these must be properly estimated and corrected.

Beschreibung: The High-Speed Research (HSR) Airfoil Alloy program developed fourth-generation single-crystal superalloys with up to an 85 F increase in creep rupture capability over current production airfoil alloys. Recent results have been generated at the NASA Glenn Research Center on these fourth-generation alloys, but in coated form, for subsonic turbine blade applications under NASA's Ultra-Efficient Engine Technology (UEET) Program. One goal for UEET is to optimize the airfoil alloy/thermal barrier coating system for 3100 F turbine inlet temperatures. The state-of-the art turbine blade airfoil system consists of a superalloy single crystal that provides the basic mechanical performance of the airfoil. A thermal barrier coating is used to reduce the temperature of the base superalloy, and a bondcoat is deposited between the base material and the thermal barrier coating. The bondcoat improves the oxidation and corrosion resistance of the base superalloy and improves the spallation resistance of the thermal barrier coating. A commercial platinum aluminide bondcoat was applied to the HSR-developed alloys, and a diffusion zone developed as a result of interaction between the bondcoat and the superalloy. Optimized strength is obtained for superalloys when the refractory element content is high and the limits of microstructural stability are approached or exceeded slightly. For fourthgeneration alloys, instability leads to the formation of topologically close packed (TCP) phases, which form internally in the superalloy, and a secondary reaction zone (SRZ), which forms under the diffusion zone. There was a concern that excessive quantities of either TCP or SRZ might decrease the mechanical properties of the superalloy, with SRZ thought to be particularly detrimental and its formation unpredictable. Thus, an SRZreduction effort was initiated in the NASA UEET Program so that methods developed during the HSR project could be optimized further to reduce or eliminate the SRZ. An SRZ is a three-phase constituent composed of TCP and stringers of gamma phase in a matrix of gamma prime. An incoherent grain boundary separates the SRZ from the gammagamma prime microstructure of the superalloy. The SRZ is believed to form as a result of local chemistry changes in the superalloy due to the application of the diffusion aluminide bondcoat. Locally high surface stresses also appear to promote the formation of the SRZ. Thus, techniques that change the local alloy chemistry or reduce surface stresses have been examined for their effectiveness in reducing SRZ. These SRZ-reduction steps are performed on the test specimen or the turbine blade before the bondcoat is applied. Stressrelief heat treatments developed at NASA Glenn have been demonstrated to reduce significantly the amount of SRZ that develops during subsequent high-temperature exposures. Stress-relief heat treatments reduce surface stresses by recrystallizing a thin surface layer of the superalloy. However, in alloys with very high propensities to form SRZ, stress relief heat treatments alone do not eliminate SRZ entirely. Thus, techniques that modify the local chemistry under the bondcoat have been emphasized and optimized successfully at Glenn. One such technique is carburization, which changes the local chemistry by forming submicron carbides near the surface of the superalloy. Detailed characterizations have demonstrated that the depth and uniform distribution of these carbides are enhanced when a stress relief treatment and an appropriate surface preparation are employed in advance of the carburization treatment. Even in alloys that have the propensity to develop a continuous SRZ layer beneath the diffusion zone, the SRZ has been completely eliminated or reduced to low, manageable levels when this combination of techniques is utilized. Now that the techniques to mitigate SRZ have been established at Glenn, TCP phase formation is being emphasized in ongoing work under the UEET Program. The limitsf stability of the fourth-generation alloys with respect to TCP phase formation are currently being defined along with high-temperature creep rupture properties. In addition, a regression model is being developed at Glenn for the prediction of the presence of TCP phase in the microstructure and SRZ under the diffusion zone. The model is based on a design-of-experiments methodology with emphasis on the potential synergistic effects of alloying elements.