707 research outputs found
Synthesis of calculational methods for the design and analysis of radiation shields for nuclear rocket systems. Volume 2 - Analysis of radiation measurements in a nuclear rocket propellant tank mockup using simulated liquid hydrogen
Calculational methods for nuclear rocket radiation shield design - analysis of radiation measurements in nuclear rocket propellant tank mockup using simulated liquid hydroge
Artemis Curation: Preparing for Sample Return from the Lunar South Pole
Space Policy Directive-1 mandates that the United States will lead the return of humans to the Moon for long-term exploration and utilization, followed by human missions to Mars and other destinations. In addition, the Vice President stated that It is the stated policy of this administration and the United States of America to return American astronauts to the Moon within the next five years, that is, by 2024. These efforts, under the umbrella of the recently formed Artemis Program, include such historic goals as the flight of the first woman to the Moon and the exploration of the lunar south-polar region. Among the top priorities of the Artemis Program is the return of a suite of geologic samples, providing new and significant opportunities for progressing lunar science and human exploration. In particular, successful sample return is necessary for understanding the history of volatiles in the Solar System and the evolution of the Earth-Moon system, fully constraining the hazards of the lunar polar environment for astronauts, and providing the necessary data for constraining the abundance and distribution of resources for in-situ resource utilization (ISRU). Here we summarize the ef-forts of the Astromaterials Acquisition and Curation Office (hereafter referred to as the Curation Office) to ensure the success of Artemis sample return (per NASA Policy Directive (NPD) 7100.10E)
Dysregulation of Prostaglandins, Leukotrienes and Lipoxin A4 in Bronchiectasis
Introduction: Bronchiectasis is characterised by excessive neutrophilic inflammation. Lipid mediators such as prostaglandins and leukotrienes have crucial roles in the inflammatory response. Further characterisation of these lipids and understanding the interplay of anti-inflammatory and proinflammatory lipid mediators could lead to the development of novel anti-inflammatory therapies for bronchiectasis.
Aim: The aim of our study was to characterise the lipids obtained from serum and airways in patients with bronchiectasis in the stable state.
Methods: Six healthy volunteers, 10 patients with mild bronchiectasis, 15 with moderate bronchiectasis and 9 with severe bronchiectasis were recruited. All participants had 60 mL of blood taken and underwent a bronchoscopy while in the stable state. Lipidomics was done on serum and bronchoalveolar lavage fluid (BALF).
Results: In the stable state, in serum there were significantly higher levels of prostaglandin E2 (PGE2), 15-hydroxyeicosatetranoic acid (15-HETE) and leukotriene B4 (LTB4) in patients with moderate–severe disease compared with healthy volunteers. There was a significantly lower level of lipoxin A4 (LXA4) in severe bronchiectasis.
In BALF, there were significantly higher levels of PGE2, 5-HETE, 15-HETE, 9-hydroxyoctadecadienoic acid and LTB4 in moderate–severe patients compared with healthy volunteers.
In the stable state, there was a negative correlation of PGE2 and LTB4 with % predicted forced expiratory volume in 1 s and a positive correlation with antibiotic courses.
LXA4 improved blood and airway neutrophil phagocytosis and bacterial killing in patients with bronchiectasis. Additionally LXA4 reduced neutrophil activation and degranulation.
Conclusion: There is a dysregulation of lipid mediators in bronchiectasis with excess proinflammatory lipids. LXA4 improves the function of reprogrammed neutrophils. The therapeutic efficacy of LXA4 in bronchiectasis warrants further studies
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CHARACTERIZATION OF TANK 50 SLURRY FOR SALTSTONE WASTE ACCEPTANCE CRITERIA, APRIL 2007 SAMPLES
This report summarizes the results from the characterization of the second quarter April 2007 sampling of Tank 50H for the Saltstone Waste Acceptance Criteria (WAC). Six one liter samples were taken in polyethylene bottles to analyze for the WAC contaminants and a 200 mL sample was taken in a steel container for analysis of volatile organic compounds. The information from this characterization will be given to Waste Solidification Engineering personnel to qualify the transfer of aqueous waste to the Saltstone Facility. The following conclusions are drawn from the analytical results found in this report: (1) All six of the one liter samples taken in April 2007 from the mixed slurry in Tank 50 have the same compositions within the experimental uncertainty of the analyses. (2) Of the ninety-one process, chemical, and radioactive WAC target or limit contaminants listed in Revision 7 of the 'Waste Acceptance Criteria for Aqueous Waste sent to the Z-Area Saltstone Production Facility', eighty-nine had concentrations that were unequivocally less than the WAC limit or target. (3) The two contaminants whose concentrations could not be shown to be less than their WAC targets were methanol and radioactive Nb-93m. Currently the AD Section of SRNL does not have a method for measuring methanol in caustic solutions. For Nb-93m the results are ambiguous due to possible interferences in the ICP-MS analysis from Zr-93 or Mo-93. (4) Of the six additional chemical and radioactive contaminants requested in the TTR for Saltstone qualification, five were measured or calculated. These were Sb, Be, Tl, along with total beta and gamma. The AD Section does not have a method to measure the 6th contaminant which was the cyanide ion
DEVELOPMENT OF A SENSOR NETWORK TEST BED FOR ISD MATERIALS AND STRUCUTRAL CONDITION MONITORING
The P Reactor at the Savannah River Site is one of the first reactor facilities in the US DOE complex that has been placed in its end state through in situ decommissioning (ISD). The ISD end state consists of a grout-filled concrete civil structure within the concrete frame of the original building. To evaluate the feasibility and utility of remote sensors to provide verification of ISD system conditions and performance characteristics, an ISD Sensor Network Test Bed has been designed and deployed at the Savannah River National Laboratory. The test bed addresses the DOE-EM Technology Need to develop a remote monitoring system to determine and verify ISD system performance. Commercial off-the-shelf sensors have been installed on concrete blocks taken from walls of the P Reactor Building. Deployment of this low-cost structural monitoring system provides hands-on experience with sensor networks. The initial sensor system consists of: (1) Groutable thermistors for temperature and moisture monitoring; (2) Strain gauges for crack growth monitoring; (3) Tiltmeters for settlement monitoring; and (4) A communication system for data collection. Preliminary baseline data and lessons learned from system design and installation and initial field testing will be utilized for future ISD sensor network development and deployment
Effective Vortex Pinning in MgB2 thin films
We discuss pinning properties of MgB2 thin films grown by pulsed-laser
deposition (PLD) and by electron-beam (EB) evaporation. Two mechanisms are
identified that contribute most effectively to the pinning of vortices in
randomly oriented films. The EB process produces low defected crystallites with
small grain size providing enhanced pinning at grain boundaries without
degradation of Tc. The PLD process produces films with structural disorder on a
scale less that the coherence length that further improves pinning, but also
depresses Tc
High-Resolution Imaged-Based 3D Reconstruction Combined with X-Ray CT Data Enables Comprehensive Non-Destructive Documentation and Targeted Research of Astromaterials
Providing web-based data of complex and sensitive astromaterials (including meteorites and lunar samples) in novel formats enhances existing preliminary examination data on these samples and supports targeted sample requests and analyses. We have developed and tested a rigorous protocol for collecting highly detailed imagery of meteorites and complex lunar samples in non-contaminating environments. These data are reduced to create interactive 3D models of the samples. We intend to provide these data as they are acquired on NASA's Astromaterials Acquisition and Curation website at http://curator.jsc.nasa.gov/
Curating NASA's Past, Present, and Future Astromaterial Sample Collections
The Astromaterials Acquisition and Curation Office at NASA Johnson Space Center (hereafter JSC curation) is responsible for curating all of NASA's extraterrestrial samples. JSC presently curates 9 different astromaterials collections in seven different clean-room suites: (1) Apollo Samples (ISO (International Standards Organization) class 6 + 7); (2) Antarctic Meteorites (ISO 6 + 7); (3) Cosmic Dust Particles (ISO 5); (4) Microparticle Impact Collection (ISO 7; formerly called Space-Exposed Hardware); (5) Genesis Solar Wind Atoms (ISO 4); (6) Stardust Comet Particles (ISO 5); (7) Stardust Interstellar Particles (ISO 5); (8) Hayabusa Asteroid Particles (ISO 5); (9) OSIRIS-REx Spacecraft Coupons and Witness Plates (ISO 7). Additional cleanrooms are currently being planned to house samples from two new collections, Hayabusa 2 (2021) and OSIRIS-REx (2023). In addition to the labs that house the samples, we maintain a wide variety of infra-structure facilities required to support the clean rooms: HEPA-filtered air-handling systems, ultrapure dry gaseous nitrogen systems, an ultrapure water system, and cleaning facilities to provide clean tools and equipment for the labs. We also have sample preparation facilities for making thin sections, microtome sections, and even focused ion-beam sections. We routinely monitor the cleanliness of our clean rooms and infrastructure systems, including measurements of inorganic or organic contamination, weekly airborne particle counts, compositional and isotopic monitoring of liquid N2 deliveries, and daily UPW system monitoring. In addition to the physical maintenance of the samples, we track within our databases the current and ever changing characteristics (weight, location, etc.) of more than 250,000 individually numbered samples across our various collections, as well as more than 100,000 images, and countless "analog" records that record the sample processing records of each individual sample. JSC Curation is co-located with JSC's Astromaterials Research Office, which houses a world-class suite of analytical instrumentation and scientists. We leverage these labs and personnel to better curate the samples. Part of the cu-ration process is planning for the future, and we refer to these planning efforts as "advanced curation". Advanced Curation is tasked with developing procedures, technology, and data sets necessary for curating new types of collections as envi-sioned by NASA exploration goals. We are (and have been) planning for future cu-ration, including cold curation, extended curation of ices and volatiles, curation of samples with special chemical considerations such as perchlorate-rich samples, and curation of organically- and biologically-sensitive samples
Comprehensive Non-Destructive Conservation Documentation of Lunar Samples Using High-Resolution Image-Based 3D Reconstructions and X-Ray CT Data
Established contemporary conservation methods within the fields of Natural and Cultural Heritage encourage an interdisciplinary approach to preservation of heritage material (both tangible and intangible) that holds "Outstanding Universal Value" for our global community. NASA's lunar samples were acquired from the moon for the primary purpose of intensive scientific investigation. These samples, however, also invoke cultural significance, as evidenced by the millions of people per year that visit lunar displays in museums and heritage centers around the world. Being both scientifically and culturally significant, the lunar samples require a unique conservation approach. Government mandate dictates that NASA's Astromaterials Acquisition and Curation Office develop and maintain protocols for "documentation, preservation, preparation and distribution of samples for research, education and public outreach" for both current and future collections of astromaterials. Documentation, considered the first stage within the conservation methodology, has evolved many new techniques since curation protocols for the lunar samples were first implemented, and the development of new documentation strategies for current and future astromaterials is beneficial to keeping curation protocols up to date. We have developed and tested a comprehensive non-destructive documentation technique using high-resolution image-based 3D reconstruction and X-ray CT (XCT) data in order to create interactive 3D models of lunar samples that would ultimately be served to both researchers and the public. These data enhance preliminary scientific investigations including targeted sample requests, and also provide a new visual platform for the public to experience and interact with the lunar samples. We intend to serve these data as they are acquired on NASA's Astromaterials Acquisistion and Curation website at http://curator.jsc.nasa.gov/. Providing 3D interior and exterior documentation of astromaterial samples addresses the increasing demands for accessability to data and contemporary techniques for documentation, which can be realized for both current collections as well as future sample return missions
Curating NASA's Past, Present, and Future Extraterrestrial Sample Collections
The Astromaterials Acquisition and Curation Office (henceforth referred to herein as NASA Curation Office) at NASA Johnson Space Center (JSC) is responsible for curating all of NASA's extraterrestrial samples. Under the governing document, NASA Policy Directive (NPD) 7100.10E "Curation of Extraterrestrial Materials", JSC is charged with "...curation of all extra-terrestrial material under NASA control, including future NASA missions." The Directive goes on to define Curation as including "...documentation, preservation, preparation, and distribution of samples for research, education, and public outreach." Here we describe some of the past, present, and future activities of the NASA Curation Office
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