ULTRASONIC LEACHING OF URANIA-IMPREGNATED GRAPHITE FUELS

The proposed use of unclad, urania-impregnated graphite fuel elements in experimental and power reactors raised the question of how best to reprocess the elements after irradiation. A grind-leach process using boiling nitric acid was previously suggested as alternate to earlier combustion techniques. Besides requiring pre-grinding of the elements the process did not leave a residue sufficiently low in radioactivity when the elements contained initially less than 3 wt% uranium. Application of ultrasonic vibratory energy tc the graphite during this process increased leaching rate and completeness tc such an extent that the practical process limit of 3% uranium is no longer a problem. The ultrasonic studies were carried out with non-irradiated specimen plates and ground pebble specimens. The plates apparently can be leached in practical time span to such a low level of radioactivity that disposal of the graphite residues is simplified. Furthermore it appears that the pre-grinding of the spent elements can be eliminated. Direct activation of the intact fuel plate specimens resulted in leaching efficiency at least as good as with ground specimens. (auth

Ares I-X Range Safety Analyses Overview

Ares I-X was the first test flight of NASA's Constellation Program's Ares I Crew Launch Vehicle designed to provide manned access to low Earth orbit. As a one-time test flight, the Air Force's 45th Space Wing required a series of Range Safety analysis data products to be developed for the specified launch date and mission trajectory prior to granting flight approval on the Eastern Range. The range safety data package is required to ensure that the public, launch area, and launch complex personnel and resources are provided with an acceptable level of safety and that all aspects of prelaunch and launch operations adhere to applicable public laws. The analysis data products, defined in the Air Force Space Command Manual 91-710, Volume 2, consisted of a nominal trajectory, three sigma trajectory envelopes, stage impact footprints, acoustic intensity contours, trajectory turn angles resulting from potential vehicle malfunctions (including flight software failures), characterization of potential debris, and debris impact footprints. These data products were developed under the auspices of the Constellation's Program Launch Constellation Range Safety Panel and its Range Safety Trajectory Working Group with the intent of beginning the framework for the operational vehicle data products and providing programmatic review and oversight. A multi-center NASA team in conjunction with the 45th Space Wing, collaborated within the Trajectory Working Group forum to define the data product development processes, performed the analyses necessary to generate the data products, and performed independent verification and validation of the data products. This paper outlines the Range Safety data requirements and provides an overview of the processes established to develop both the data products and the individual analyses used to develop the data products, and it summarizes the results of the analyses required for the Ares I-X launch

Efficient ultrasonic grinding: a new technology for micron-sized coal. Quarterly technical progress report No. 1, September 15-December 15, 1979

During the first quarter, preliminary testing demonstrated the ability of ultrasonically enhanced comminution to increase fraction of -200 mesh particles by 100 to 500% over mechanical grinding alone. Modification of the preliminary ultrasonic comminution process to include cycles of ultrasonic activation followed by removal of fines has shown a significant increase in the production of -325 mesh particles (-44 microns) with substantial fractions in the -20 micron and -10 micron ranges. Efforts to characterize coal samples have yielded a correlation between Hardgrove Grindability Index (HGI) and susceptibility to ultrasonic comminution. This information, along with other considerations and data relating to the cost effectiveness of industrial ultrasonic comminution, will be used to select coal samples for the Phase II experiments. While several preliminary equipment configurations have been used, their purpose has been mainly to verify the mechanism of ultrasonic comminution and to secure information for the design and fabrication of optimized laboratory apparatus for Phase II testing. On this basis a nip configuration has been selected to insure contact throughout the ultrasonic activation period and prevent coal particle compaction

Efficient ultrasonic grinding: a new technology for micron-sized coal. Quarterly technical progress report No. 2, December 16, 1979-March 15, 1980

Work focused on establishing experimentally determined parameters for ultrasonic comminution and their translation into the design of an ultrasonic comminution array for Phase I testing. Early work indicated that continuous removal of fines during communition could significantly increase the production of -10 micron particles. Similarly, varying the mechanical gain of the ultrasonic comminution apparatus and thereby increasing the strain amplitude of the system was shown to enhance fines production. A gain of 3:1 (i.e., a three-fold increase in strain amplitude) produced the best results. These features used with an ultrasonic cylinder segment apparatus resulted in 276% increase in the production of -10 micron fines over that generated by passing coal through a non-activated control. Thus influenced, the design of the Phase I ultrasonic comminution apparatus will incorporate both a dual-roll and roller/plate capability; it will provide continuous flow of particles through the region of ultrasonic activation, thus permitting removal of fines as they are comminuted; and will function with a gain of 3:1. The Phase I apparatus also offers the flexibility of operating with either traveling or standing ultrasonic waves. Varying the physical configuration (dual-roller or roller plate) and the mode of ultrasonic activation (traveling or standing wave) allows for cost effective testing of four different techniques. Additionally, operating frequency has been reduced to 15 kHz to permit use of off-the-shelf hardware in apparatus assembly and thus expedite testing. Selection of four representative, well-characterized coals has been completed; after initial testing, 200 lb. quantities of two of the samples will be secured for Phase II experimentation

Biomarker metabolites capturing the metabolite variance present in a rice plant developmental period

BACKGROUND: This study analyzes metabolomic data from a rice tillering (branching) developmental profile to define a set of biomarker metabolites that reliably captures the metabolite variance of this plant developmental event, and which has potential as a basis for rapid comparative screening of metabolite profiles in relation to change in development, environment, or genotype. Changes in metabolism, and in metabolite profile, occur as a part of, and in response to, developmental events. These changes are influenced by the developmental program, as well as external factors impinging on it. Many samples are needed, however, to characterize quantitative aspects of developmental variation. A biomarker metabolite set could benefit screening of quantitative plant developmental variation by providing some of the advantages of both comprehensive metabolomic studies and focused studies of particular metabolites or pathways. RESULTS: An appropriate set of biomarker metabolites to represent the plant developmental period including the initiation and early growth of rice tillering (branching) was obtained by: (1) determining principal components of the comprehensive metabolomic profile, then (2) identifying clusters of metabolites representing variation in loading on the first three principal components, and finally (3) selecting individual metabolites from these clusters that were known to be common among diverse organisms. The resultant set of 21 biomarker metabolites was reliable (P = 0.001) in capturing 83% of the metabolite variation in development. Furthermore, a subset of the biomarker metabolites was successful (P = 0.05) in correctly predicting metabolite change in response to environment as determined in another rice metabolomics study. CONCLUSION: The ability to define a set of biomarker metabolites that reliably captures the metabolite variance of a plant developmental event was established. The biomarker metabolites are all commonly present in diverse organisms, so studies of their quantitative relationships can provide comparative information concerning metabolite profiles in relation to change in plant development, environment, or genotype

Genome wide association mapping of grain arsenic, copper, molybdenum and zinc in rice (Oryza sativa L.) grown at four international field sites

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