Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Air Sampling”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,333 records · Page 74

Prediction of the mechanical properties of a filled elastomer in vacuum

Constant force creep measurements were made at three stress levels on samples of an ammonium perchlorate filled butadiene-acrylic acid copolymer in vacuum and in the atmosphere (air, 50% relative humidity) at a temperature of 28 C. The creep compliance of the samples decreased as much as 50% after 14 days of vacuum exposure. Shift factors were developed which, when applied to the atmospheric compliance measurements, predicted the behavior in vacuum. The experimental results led to the following conclusions: (1) shift factors can be applied to predict compliance behavior in vacuum from measurements in air, and (2) the shift factors are independent of stress but increase in magnitude with increasing vacuum exposure.

Gregory, G. L.↗

Instrument for spatially resolved, temperature-dependent electrochemical impedance spectroscopy of thin films under locally controlled atmosphere

We demonstrate an instrument for spatially resolved measurements (mapping) of electrochemical impedance under various temperatures and gas environments. Automated measurements are controlled by a custom LabVIEW program, which manages probe motion, sample motion, temperature ramps, and potentiostat functions. Sample and probe positioning is provided by stepper motors. Dry or hydrated atmospheres (air or nitrogen) are available. The configurable heater reaches temperatures up to 500 °C, although the temperature at the sample surface is moderated by the gas flow rate. The local gas environment is controlled by directing flow toward the sample via a glass enclosure that surrounds the gold wire probe. Software and hardware selection and design are discussed. Reproducibility and accuracy are quantified on a Ba(Zr,Y)O 3-δ proton-conducting electrolyte thin film synthesized by pulsed laser deposition. The mapping feature of the instrument is demonstrated on a compositionally graded array of electrocatalytically active Ba(Co,Fe,Zr,Y)O 3-δ thin film microelectrodes. The resulting data indicate that this method proficiently maps property trends in these materials, thus demonstrating the reliability and usefulness of this method for investigating electrochemically active thin films.

47 OTHER INSTRUMENTATION↗

Effect of hydrocarbon adsorption on the wettability of rare earth oxide ceramics

Vapor condensation is routinely used as an effective means of transferring heat, with dropwise condensation exhibiting a 5 − 7x heat transfer improvement compared to filmwise condensation. However, state-of-the-art techniques to promote dropwise condensation rely on functional hydrophobic coatings, which are often not robust and therefore undesirable for industrial implementation. Natural surface contamination due to hydrocarbon adsorption, particularly on noble metals, has been explored as an alternative approach to realize stable dropwise condensing surfaces. While noble metals are prohibitively expensive, the recent discovery of robust rare earth oxide (REO) hydrophobicity has generated interest for dropwise condensation applications due to material costs approaching 1% of gold; however, the underlying mechanism of REO hydrophobicity remains under debate. In this work, we show through careful experiments and modeling that REO hydrophobicity occurs due to the same hydrocarbon adsorption mechanism seen previously on noble metals. To investigate adsorption dynamics, we studied holmia and ceria REOs, along with control samples of gold and silica, via X-Ray photoelectron spectroscopy (XPS) and dynamic time-resolved contact angle measurements. The contact angle and surface carbon percent started at ≈0 on in-situ argon-plasma-cleaned samples and increased asymptotically over time after exposure to laboratory air, with the rare earth oxides displaying hydrophobic (>90°) advancing contact angle behavior at long times (>4 days). The results indicate that REOs are in fact hydrophilic when clean and become hydrophobic due to hydrocarbon adsorption. Furthermore, this study provides insight into how REOs can be used to promote stable dropwise condensation, which is important for the development of enhanced phase change surfaces.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

MOSAiC-Colorado State University Ice Spectrometer

This data set contains atmospheric ice nucleating particle (INP) measurements, using Colorado State University&rsquo;s (CSU) Ice Spectrometer (IS), of filter collections taken at the U.S. DOE ARM AMF2 site onboard the R/V Polarstern P-deck during the Multidisciplinary Drifting Observatory for the Study of Arctic Climate (MOSAiC) field campaign. Samples were collected from October 27, 2019 to September 24, 2020. A filter sampler was mounted approximately 15 m above ground level on a railing in proximity to (and approximately 3 m below) the Aerosol Observation System (AOS) inlet. Single-use filter units open to the atmosphere were pre-cleaned and pre-loaded with 47-mm diameter Nuclepore polycarbonate (0.2 &micro;m pore-diameter) filters. Filters were typically drawn for a three-day period, with an average volume of air filtered of 87,000 standard liters. Total volumes were calculated through recorded daily flow rates using a mass flow meter (TSI). After collection, filters were stored and transported frozen until analysis using CSU&rsquo;s IS instrument (McCluskey et al., 2018). Aerosol particles were first re-suspended in 8 mL of 0.1 &micro;m-filtered deionized (DI) water. Aliquots of each suspension, and corresponding 11-fold dilutions, were dispensed into polymerase chain reaction (PCR) trays and placed into the aluminum blocks of the IS. Samples were cooled at approximately 0.33 &deg;C min -1 and freezing detected optically with corresponding temperatures recorded. Cumulative INP concentrations were determined through calculating the number of INPs per mL of suspension (Vali, 1971) and converting to concentration per standard L of air by accounting for the proportion of liquid used and volume of air collected. All samples were corrected for the number of INPs on the average of four field blanks (cleaned, handled, transported, and analyzed in the same way without air flow). Two-tailed, 95% confidence intervals for binomial sampling are provided (Agresti and Coull, 1998). Select samples were also heat treated (95 &deg;C for 20 min) to denature and deactivate biological INPs present and digested in 10% H 2 O 2 at 95 &deg;C under UV-B for 20 min to remove any organic carbon INPs. Agresti, A, and BA Coull. 1998. "Approximate is better than &ldquo;exact&rdquo; for interval estimation of binomial proportions." American Statistics 52: 119&ndash;126. https://doi.org/10.2307/2685469 McCluskey, CS, J Ovadnevaite, M Rinaldi, J Atkinson, F Belosi, D Ceburnis, &hellip; and PJ DeMott. 2018. "Marine and Terrestrial Organic Ice-Nucleating Particles in Pristine Marine to Continentally Influenced Northeast Atlantic Air Masses." Journal of Geophysical Research: Atmospheres 123 (11): 6196&ndash;6212, https://doi.org/10.1029/2017JD028033 Vali, G. 1971. "Quantitative Evaluation of Experimental Results and the Heterogeneous Freezing Nucleation of Supercooled Liquids." Journal of the Atmospheric Sciences 28: 402-209. https://doi.org/10.1175/1520-0469(1971)028<0402:QEOERA>2.0.CO;2

54 ENVIRONMENTAL SCIENCES↗

Space Age Archaeology

In 1985, the Egyptian Antiques Organization (EAO) asked Dr. Farouk El-Baz whether it would be possible to examine and sample the second chamber of the subterranean chamber carved in the bedrock near the Great Pyramid of Khufu in Giza, Egypt, without admitting people, air or contaminants. He felt it could by applying space technology to the task. The initial contact led to a two year project which he organized and headed a team, co-sponsored by EAO and the National Geographic Society (NGS), to apply space technology in an effort to examine and photograph the Giza Chamber. The NGS photographic division modified and tested a remotely controlled video system and a 35-millimeter camera, and developed a lighting system that would not elevate the chamber temperature. Still needed was a drill to cut through the limestone cap without using lubricants or cooling fluids that might contaminate the chamber, and an airlock that would admit the drill shaft and photo equipment but not the air. Bob Moores from Black & Decker Corporation tailored a new drill to the Giza exploration. The drill bit broke through into the chamber at a depth of 63 inches, a stainless steel tube was lowered through the airlock to take samples of the chamber air at several levels. The video camera sent images from the chamber revealing that there was a disassembled royal boat that had been there.

Source record↗

Use of a Pressurized Water Treatment to Prevent Cracking of Internal Gelation Sol-Gel Microspheres

Pressurized water treatments were investigated as a means to prevent cracking of internal gelation sol-gel microspheres upon drying and heating. A batch of gelled cerium oxide microspheres was prepared, split into two samples that were processed with and without a pressurized water treatment, and dried in air at room temperature. Thermal gravimetric analysis was used to compare the mass loss profiles between the two samples and to understand volatile emissions from cerium oxide microspheres during heat treatments up to 600 °C. Microspheres that were processed without a pressurized water treatment lost approximately 4.6 times more mass upon heating than microspheres that were subjected to a pressurized water treatment. Comparison of the cracking behavior of microspheres prepared with and without a pressurized water treatment indicated that microspheres subjected to a pressurized water treatment were virtually crack-free after heat treatments. Conversely, microspheres processed without a pressurized water treatment, which is typical of traditional washing processes, exhibited extensive cracking. Analysis of residues dried from pressurized water treatment effluents indicated that hexamethylenetetramine and urea, which are excess reactants from the internal gelation process, were removed from gelled microspheres during the pressurized water treatment step. Traditional processing methods for preparing internal gelation microspheres use specific feed solution and gelation parameters to reduce subsequent cracking upon drying and heating. Results from this study indicate that more aggressive gel-forming conditions may be used to produce crack-free microspheres, if a pressurized water treatment step is included after washing and before air-drying.

cerium oxide, internal gelation, microsphere, TRIS↗

Installing Deep Groundwater Monitoring Wells in a Volcanic Dominated Rift Basin: Los Alamos National Laboratory, New Mexico - 17594

Los Alamos National Laboratory (LANL, or the Laboratory) is located in northern New Mexico near the west margin of the Espanola Basin. LANL is underlain by a complex basin-fill sequence of alluvial fan deposits, volcanic tuff, basaltic and dacitic lavas, and riverine deposits. On-going environmental remediation and characterization activities have evolved to improve the performance of groundwater monitoring wells, ensuring they yield representative groundwater and core samples. Groundwater occurs as canyon-fill alluvial water, perched intermediate-depth water associated with the basalts and other local-scale perching horizons, and as a regional-scale aquifer that is the main water supply for the area. Anthropogenic contaminants are found in all three groundwater zones. The regional aquifer below LANL is nominally 1000-1400 feet below ground surface (bgs). Monitoring wells at the Laboratory, are therefore, among the deepest routinely installed in the US. Logistical challenges at LANL include steep terrain, widespread cultural sites, and threatened and endangered species habitat restrictions. Additionally, the cost of installing monitoring wells is high because of groundwater depths and the variable drilling techniques that are required to characterize and install wells in a complex geologic environment. A major challenge to the characterization approach at LANL has been to meet sample quality requirements while minimizing drilling costs. In the late 1990's threaded drill-casing was advanced by rotary drilling methods using compressed air as the only circulation fluid. This resulted in relatively low impacts to the geochemical integrity of rock and groundwater samples, but led to frequent episodes of stuck casing. Additional fluids were introduced to the air-rotary program, improving penetration rates, but also resulting in non-representative groundwater samples due to long-term impacts to the aquifer in the vicinity of the well screen. Mud-rotary drilling was incorporated into the program, but it also had significant long-term impacts on groundwater quality, and often inhibited identification of perched groundwater zones and accurate identification of the water table in the regional aquifer. Current drilling practice makes limited use of fluid additives (e.g. foam) to supplement air circulation methods in order to advance drill casing through the vadose zone. Starting about 100 feet above the water table, drill casing is advanced to the target horizon in the regional aquifer using only air and municipal water (when needed) for circulation. Additionally, the threaded drill casing couplings have been replaced with welded connections, significantly reducing the occurrence of stuck casing. Careful observations of water production and water levels during drilling, coupled with the ability to retract casing for video and geophysical logs, now allows for robust characterization of perched groundwater systems and accurate definition of the top of regional saturation. Recent advances in the drilling program include combined dual-rotary/sonic drilling to depths up to 1150 feet and dual-rotary casing advance at angles up to 25 deg. from vertical. The former allows for core collection with minimal fluid addition, thereby preserving pore water chemistry. The latter method allows for well installation into portions of the aquifer otherwise inaccessible due to constraints at the surface (e.g., cultural sites or topography). Similar to the development of drilling techniques, both well design and groundwater sampling system design have evolved throughout the program. Current well design emphasizes a minimal annulus of filter pack, maximum screen slot size based on formation sieve analyses, and thorough well development to mitigate formation damage due to drilling. To sample groundwater at multiple levels in the same well, earlier sampling systems included Westbay{sup R} multi-zone systems and dual-screen single-pump and dual-screen dual-pump systems designed in collaboration with Baski, Inc. These multi-zone sampling systems proved difficult to develop and maintain given the depth to groundwater, and most current well installations are configured with a single screen and a submersible pump. The ability to purge from a well-developed single-screen well has substantially improved the collection of representative groundwater samples. A carefully crafted groundwater characterization program in target aquifers at depths ranging from 1,000 to 1,400 feet bgs within a complex geologic setting, while also retaining the ability to collect representative core and groundwater samples, may have application at a number of sites throughout the environmental industry. Optimizing each well to meet program objectives while reducing total project costs benefits all environmental investigations. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Optical/electrical correlations in ZnO. The plasmonic resonance phase diagram

The Drude equation for dielectric constant ϵ(E) depends on four parameters: ϵ∞, effective mass m*, optical mobility µopt, and optical carrier concentration nopt. By solving this equation at ϵ(Eres)=0, we obtain a relationship between µopt and nopt at constant plasmonic resonance energy Eres [or wavelength λres (µm)=1.2395/Eres (eV)]. A family of µopt versus nopt curves covering a range of λres values (including the limiting wavelength λres=∞) constitutes a plasmonic resonance phase diagram (PRPD) for a semiconductor defined by only ϵ∞ and m*. The PRPD is a convenient instrument that allows an immediate prediction of λres from Hall-effect measurements of µH and nH. We apply the PRPD analysis to a series of ten ZnO samples grown by pulsed laser deposition at 200°C in an ambient of 33%H2:67%Ar and annealed in 25°C steps for 10 min in air at various temperatures from 400 to 600°C. For the samples annealed at 550°C or lower, the µH/nH points yield predicted values of λres that range from 1.07 to 2.80 µm; however, the 575 and 600°C samples are predicted to have no resonance at all. Reflectance curves for the eight samples annealed up to 550 °C decrease slowly from 6 eV down to about Eres= 0.5–1.15 eV, and then increase rapidly for E < Eres. In contrast, there is no such resonance-related increase for the 575 and 600 °C samples. Satisfactory agreement is found between the reflectance minima and the Hall-effect-predicted values of λres.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Preferential concentration of certain elements in smaller aerosols emitted from aircraft engines

Aerosols from aircraft engines were collected with an eight-stage cascade sampler for a period of 24 h. The aerosol samples from each stage were analyzed for their elemental composition using the proton-induced X-ray emission (PIXE) technique. Seventeen elements (Si, P, S, Cl, K, Ca, Ti, V, Fe, Ni, Cu, Zn, Br, Sr, Nb, Sn, and Pb) were positively identified and quantitated at each stage. Six elements (S, Ca, Fe, Zn, Sn, and Pb) showed a fractional concentration increase with decreasing aerosol size. Similar, but less well-defined, trends were also observed for V and Ni. Silicon and chlorine, on the other hand, showed an opposite trend. Neutron-activation analysis of bulk aerosol samples collected every 2 h over the same period showed a correlation between concentration of Si, Ca, V, Ti, Zn, Br, and Sn and the density of air traffic at the airport. Analysis of the aviation-fuel samples by PIXE indicates that major fractions of Pb, Sn, Br, Zn, Ni, Fe, V, Ca, and S observed in these aerosol studies come from the aircraft engine exhaust.

Jolly, R. K.↗

Microstructure and DC electrical conductivity of spinel nickel ferrite sintered in air and nitrogen atmospheres

In recent years, the development of inert anode materials has gained considerable attention because such materials are capable of producing only environment-friendly O{sub 2} and saving energy during aluminum electrolysis. Nickel ferrite was prepared by a solid-state reaction as the inert anode in this study and its microstructures and direct current conductivities were analyzed in detail regarding the effects of different sintering atmospheres. A single-phase spinel structure was confirmed for all samples by X-ray powder diffraction. The grain sizes and the relative densities of the samples sintered in nitrogen increased by over 7 {mu}m and 10.8%, respectively, compared to those sintered in air. The direct current conductivities of the samples sintered in nitrogen showed a drastic increase compared to those sintered in air, believed to be due to the effects of increased Fe{sup 2+} ion concentration at octahedral sites and the increase of the relative density.

36 MATERIALS SCIENCE↗

Non-vacuum growth of graphene films using solid carbon source

This study demonstrates that air annealing can grow high-quality graphene films on the surface of polycrystalline nickel film with the help of an effective SiO{sub 2} capping layer. The number of graphene layers can be modulated by the amount of carbon embedded in the Ni film before annealing. Raman analysis results, transmission electron microscopy images, and electron diffraction patterns of the samples confirm that graphene films can be grown in air with an oxygen blocking layer and a 10 °C/s cooling rate in an open-vented rapid thermal annealing chamber or an open tube furnace. The high-quality low-defect air-annealing grown graphene is comparable to commercially available graphene grown via chemical vapor deposition. The proposed graphene growth using air annealing technique is simple and low-cost, making it highly attractive for mass production. It is transfer-free to a silicon substrate and can speed up graphene development, opening up new applications.

77 NANOSCIENCE AND NANOTECHNOLOGY↗

Adrenal Stress Hormone Regulation of Hepatic Homeostatic Function After an Acute Ozone Exposure in Wistar-Kyoto Male Rats

Ozone-induced lung injury, inflammation, and pulmonary/hypothalamus gene expression changes are diminished in adrenalectomized (AD) rats. Acute ozone exposure induces metabolic alterations concomitant with increases in epinephrine and corticosterone. We hypothesized that adrenal hormones are responsible for observed hepatic ozone effects, and in AD rats, these changes would be diminished. In total, 5–7 days after sham (SH) or AD surgeries, male Wistar-Kyoto rats were exposed to air or 0.8-ppm ozone for 4 h. Serum samples were analyzed for metabolites and liver for transcriptional changes immediately post-exposure. Ozone increased circulating triglycerides, cholesterol, free fatty-acids, and leptin in SH but not AD rats. Ozone-induced inhibition of glucose-mediated insulin release was absent in AD rats. Unlike diminution of ozone-induced hypothalamus and lung mRNA expression changes, AD in air-exposed rats (AD-air/SH-air) caused differential hepatic expression of ~1000 genes. Likewise, ozone in AD rats caused differential expression of ~1000 genes (AD-ozone/AD-air). Ozone-induced hepatic changes in SH rats reflected enrichment for pathways involving metabolic processes, including acetyl-CoA biosynthesis, TCA cycle, and sirtuins. Upstream predictor analysis identified similarity to responses produced by glucocorticoids and pathways involving forskolin. These changes were absent in AD rats exposed to ozone. However, ozone caused unique changes in AD liver mRNA reflecting activation of synaptogenesis, neurovascular coupling, neuroinflammation, and insulin signaling with inhibition of senescence pathways. In these rats, upstream predictor analysis identified numerous microRNAs likely involved in glucocorticoid insufficiency. These data demonstrate the critical role of adrenal stress hormones in ozone-induced hepatic homeostasis and necessitate further research elucidating their role in propagating environmentally driven diseases.

Toxicology↗

Investigation and modeling of the degradation of zirconium-based fuel cladding during corrosion in steam and air-steam mixtures at high temperatures - 2016-0033

This paper presents the main results of a study conducted to quantify and to model the degradation state of zirconium-based fuel claddings submitted to severe-accident conditions in a nuclear reactor core: high temperatures and either pure steam or an air-steam mixture. Due to the progressive thickening of a dense and protective ZrO{sub 2} layer, the oxidation kinetics of zirconium-based claddings in steam at high temperatures typical of severe nuclear accidents are generally cubic or parabolic. However, for some temperature domains, this oxide layer may crack, becoming porous and no longer protective. In these 'breakaway' conditions, the oxidation kinetics change from (sub)parabolic to linear or even accelerated. In addition, the temperature increase can lead core materials to melt and to relocate down to the vessel lower head, threatening its integrity. If it fails, and for specific conditions, air ingress may take place into the reactor. Hence, oxygen and nitrogen both react with zirconium-based claddings successively through the oxidation of zirconium (forming a ZrO{sub 2} layer), nitriding of zirconium (forming zirconium nitride particles), and the oxidation of zirconium nitride (forming ZrO{sub 2} and releasing nitrogen). These self-sustained chemical reactions enhance the deterioration of zirconium-based claddings and their ZrO{sub 2} layers, inducing an increase in their open porosity. To quantify this porosity, a series of two-step experiments was conducted. First, ZIRLO{sup TM} cladding samples were isothermally oxidized in pure steam or in a 50:50 mol% air-steam mixture at several different temperatures and durations. The main thermal effects on reaction kinetics and the high impact of air on the cladding degradation were all confirmed by experimental results. Second, pioneering porosimetry measurements by mercury intrusion were realized for the first time on such corroded cladding samples. In both atmospheres, it was pointed out that 1,200 and 1,250 K led to particularly porous oxide layers, especially due to strong breakaway effects. Moreover, we confirmed that the presence of air strongly enhances the oxide cracking: cladding samples were more porous when oxidized in the air-steam mixture than under pure steam. Finally, we observed that in all conditions, the open porous volume fraction of ZIRLO claddings continuously rose during their corrosion process. Hence, for each experimental condition, porosity correlations were determined through linear regressions, and porosity increase rates were deduced by derivation versus time and validated against porosimetry results of cladding samples corroded in transient nonisothermal) conditions. (authors)

36 MATERIALS SCIENCE↗

Surface chemical reaction of laser ablated aluminum sample for detonation initiation

We explore the evolution of metal plasma generated by high laser irradiances and its effect on the surrounding air by using shadowgraph images after laser pulse termination; hence the formation of laser supported detonation and combustion processes has been investigated. The essence of the paper is in observing initiation of chemical reaction between ablated aluminum plasma and oxygen from air by inducing high power laser pulse (>1000 mJ/pulse) and conduct a quantitative comparison of chemically reactive laser initiated waves with the classical detonation of exploding aluminum (dust) cloud in air. Findings in this work may lead to a new method of initiating detonation from metal sample in its bulk form without the need of mixing nano-particles with oxygen for initiation.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

Calcium titanate (CaTiO{sub 3}) dielectrics prepared by plasma spray and post-deposition thermal treatment

Highlights: • Calcium titanate was sprayed by two different plasma spray systems. • Significant improvement of dielectric properties after annealing was observed. • Calcium titanate self-supporting parts can be fabricated by plasma spraying. - Abstract: This paper studies calcium titanate (CaTiO{sub 3}) dielectrics prepared by plasma spray technology. A water stabilized plasma gun (WSP) as well as a widely used gas stabilized plasma gun (GSP) were employed in this study to deposit three sample sets at different spray conditions. Prepared specimens were annealed in air at atmospheric pressure for 2 h at various temperatures from 530 to 1170 °C. X-ray diffraction (XRD), Raman spectroscopy and porosity measurements were used for sample characterization. Dielectric spectroscopy was applied to obtain relative permittivity, conductivity and loss factor frequency dependence. Band gap energy was estimated from reflectance measurements. The work is focused on the explanation of changes in microstructure and properties of a plasma sprayed deposit after thermal annealing. Obtained results show significant improvement of dielectric properties after thermal annealing.

36 MATERIALS SCIENCE↗

Noble Gases in Samples Returned From Asteroids Ryugu and Bennu

Introduction: The asteroid sample return missions, JAXA’s Hayabusa2 [1] and NASA’s OSIRIS-REx [2], fromC-rich asteroids Ryugu and Bennu offer unique opportunities to sample pristine early solar system material, unaffected by terrestrial weathering and contamination, and with a known geological context. The comparison with most primi-tive members of carbonaceous –and inner solar system ordinary and enstatite– chondrite classes allows us to (i) assess the variation (or the lack of thereof) of the distribution of the most volatile elements throughout the entire early solar system, (ii) determine the effects of parent body thermal and aqueous alteration, and (iii) learn about the dynamic evolution and history of the various parent bodies, as sampled by both return missions and meteorite delivery. Here we will present noble gas data obtained from newly received particles from Ryugu and Bennu. Samples & Analysis: We received nine particles allocated by JAXA, with masses of 0.5-1.7 mg mass: four col-lected during Hayabusa2’s first touchdown (chamber A) and five from a small artificial crater (chamber C). We received three particles from Bennu of 0.07, 0.89 and 0.94 mg mass (OREX-800032-102/3/4). All particles were processed, allocated, weighed, and transferred into our UHV sample chamber within pure N2, to prevent any contact with air. We examined all He-Xe isotopes with our custom-built mass spectrometer “Albatros” ([3,4]). Gases were extracted individually from each particle by melting induced by a 1064 μm Nd:YAG IR laser in 2–4 heating steps. Large amounts of water and other reactive volatiles were released, consistent with the presence of abundant volatiles from both Ryugu and Bennu. Residues of Ryugu particles remaining after lasering, subsequently exposed to air, were additionally extracted in a crucible to verify complete gas extraction. Only the particle that still showed a “crystalline” structure after lasering contained detectable Ryugu noble gases, whereas all other particles turned immediately into glassy spheres by laser heating and lacked any gas. Results & Discussion: Ryugu and Bennu matter contains noble gases similar to the most pristine, unheated aqueously altered meteorites, e.g., CM or CI chondrites [5,6]. Remarkably, all four chamber A samples that originated from Ryugu’s surface show solar wind (SW) Ne (trapped (20Ne/22Ne)tr ~12–13), whereas all five chamber C samples do not ((20Ne/22Ne)tr ~9.0–10.7 consistent with the presence of non-solar trapped Ne components such as Q and HL). This demonstrates that JAXA’s sampling strategy succeeded: Chamber C samples analyzed in this work originated from areas shielded from SW, slightly below the surface, that was sampled after the impactor excavated material. The three Bennu particles populate the same range as the Ryugu particles in Ne isotope space with one particle containing SW suggesting that it was part of the uppermost surface layer of Bennu during sampling, while Ne in the smallest sample can be explained best by mixing Ne from presolar diamonds and SiC or graphite, and that in the third one by mixing of, e.g., Q and HL. Using cosmic ray production rates given by [7] yields preliminary exposure ages for Ryugu particles in the same range as determined in [7]. There is, as expected, also no systematic difference between samples from chambers A and C because both sample sets were likely collected within the uppermost layer of Ryugu, which were not shielded from cosmic rays. The concentration of cosmogenic (cos) Ne in the Bennu particle, where Necos was resolvable, is in the same range as found for Ryugu, suggesting roughly similar exposure time to cosmic rays for 5–8 Ma for all particles examined here. The Xe isotopic compositions of all particles are consistent with those of phase Q, with small additions of Xe-HL from presolar diamonds and excess 129Xe* from short-lived 129I decay. The comparably high 129Xe*/129XeQ ratio is similar in all samples, suggesting similar initial I concentrations and closure to Xe loss –or the incorporation of a well-mixed Xe reservoir. The Bennu material was in brief contact with air in the capsule, after atmospheric entry and before storage in pure N2 in a clean room. Both, the –most diagnostic– Xe isotopes and the Ar/Xe vs. Kr/Xe systematics prove that the noble gases are not affected by terrestrial contamination, in contrast to many CI, CY, and CM chondrites found on Earth [5,6], illustrating the importance of sample return. He-Xe concentrations in all particles unaffected bySW are comparable to but at the upper end of ranges reported [5-7]. In accordance with the strong aqueous alteration experienced on the parent bodies of Ryugu and Bennu [1,2], all samples lack the Ar-rich and water-susceptible noble gas components found in less aqueously altered CMs or CRs [e.g., 5,8] and all COs.

Henner Busemann↗

Atmospheric Soundings from AIRS/AMSU/HSB

AIRS was launched on EOS Aqua on May 5, 2002, together with AMSU A and HSB, to form a next generation polar orbiting infrared and microwave atmospheric sounding system. The primary products of AIRS/AMSU/HSB are twice daily global fields of atmospheric temperature-humidity profiles, ozone profiles, sea/land surface skin temperature, and cloud related parameters including OLR. The sounding goals of AIRS are to produce 1 km tropospheric layer mean temperatures with an RMS error of 1K, and 1 km layer precipitable water with an rms error of 1K, and 1 km layer precipitable water with an rms error of 20 percent, in cases with up to 80 percent cloud cover. The AIRS data products are significant for studying climate variability and change, as well as for use in initialization of General Circulation Models with the objective of improving analysis fields and subsequent forecast skill. Data assimilation experiments to evaluate the impact of AIRS retrievals on analysis and forecast skill are being conducted. Sample fields of parameters retrieved from AIRS/AMSU/HSB data will be presented and validated as a function of retrieved fractional cloud cover. Select fields will also be compared to those contained in the ECMWF analysis, done without the benefit of AIRS data, on both an instantaneous and monthly mean basis, to demonstrate information that AIRS can add to that already contained in the ECMWF analysis.

Susskind, Joel↗