Superconductivity in zirconium-rhodium alloys

Metallographic studies and transition temperature measurements were made with isothermally annealed and water-quenched zirconium-rhodium alloys. The results clarify both the solid-state phase relations at the Zr-rich end of the Zr-Rh alloy system and the influence upon the superconducting transition temperature of structure and composition

Data Managers’ Perspectives on Designated Communities and FAIR Principles

Poster presented at Drexel-CODATA FAIR-RRDM Workshop, Philadelphia, PA https://conference.codata.org/Drexel_CODATA_2019/posters/This poster presents preliminary findings of the study on data managers’ perspectives on changes in the Designated Community, related evolution of support services provided by the repository, and the FAIR Principles. The study examines the case of the Petroleum Database Management System (PDMS) hosted by the Indiana Geological and Water Survey (IGWS), a research institute of Indiana University.IMLS grant RE-02-14-0023 “Integrated doctoral education with application to scholarly communication

A Practical, Affordable Cryogenic Propellant Depot Based on ULA's Flight Experience

Mankind is embarking on the next step in the journey of human exploration. We are returning to the moon and eventually moving to Mars and beyond. The current Exploration architecture seeks a balance between the need for a robust infrastructure on the lunar surface, and the performance limitations of Ares I and V. The ability to refuel or top-off propellant tanks from orbital propellant depots offers NASA the opportunity to cost effectively and reliably satisfy these opposing requirements. The ability to cache large orbital quantities of propellant is also an enabling capability for missions to Mars and beyond. This paper describes an option for a propellant depot that enables orbital refueling supporting Exploration, national security, science and other space endeavors. This proposed concept is launched using a single EELV medium class rocket and thus does not require any orbital assembly. The propellant depot provides cryogenic propellant storage that utilizes flight proven technologies augmented with technologies currently under development. The propellant depot system, propellant management, flight experience, and key technologies are also discussed. Options for refueling the propellant depot along with an overview of Exploration architecture impacts are also presented

Scholarly Needs for Text Analysis Resources: A User Assessment Study for the HathiTrust Research Center

The HathiTrust Research Center (HTRC) is undertaking a study to better understand the needs of current and potential users of the center’s tools and services for computational text analysis. In this paper, we report on the results of the first phase of the study, which consisted of interviews with scholars, administrators, and librarians whose work involves text data mining. Our study reveals that text analysis workflows are specific to the individual research project and are often nonlinear. In spite of, and in some cases because of, the wealth of textual data available, scholars find it most difficult to locate, access, and curate textual data for their research. While the goals of the study directly relate to research and development for the HTRC, our results are useful for other large-scale data providers developing solutions for allowing computational access to their content

Settled Cryogenic Propellant Transfer

Cryogenic propellant transfer can significantly benefit NASA s space exploration initiative. LMSSC parametric studies indicate that "Topping off" the Earth Departure Stage (EDS) in LEO with approx.20 mT of additional propellant using cryogenic propellant transfer increases the lunar delivered payload by 5 mT. Filling the EDS to capacity in LEO with 78 mT of propellants increases the delivered payload by 20 mT. Cryogenic propellant transfer is directly extensible to Mars exploration in that it provides propellant for the Mars Earth Departure stage and in-situ propellant utilization at Mars. To enable the significant performance increase provided by cryogenic propellant transfer, the reliability and robustness of the transfer process must be guaranteed. By utilizing low vehicle acceleration during the cryogenic transfer the operation is significantly simplified and enables the maximum use of existing, reliable, mature upper stage cryogenic-fluid-management (CFM) techniques. Due to settling, large-scale propellant transfer becomes an engineering effort, and not the technology development endeavor required with zero-gravity propellant transfer. The following key CFM technologies are all currently implemented by settling on both the Centaur and Delta IV upper stages: propellant acquisition, hardware chilldown, pressure control, and mass gauging. The key remaining technology, autonomous rendezvous and docking, is already in use by the Russians, and must be perfected for NASA whether the use of propellant transfer is utilized or not

Advances in the Physical Metallurgy of Uranium and its Alloys

A general survey is presented of information in the uranium alloy field. Emphasis is centered on alpha uranium-rich alloys of special interest as uranium- base fuel element materials. The systems treated include uranium-molybdenum, uranium-silicon, uraniumzirconium, uranium-niobium, and uranium-zirconiumniobium (high uranium compositions). The uraniumfissium alloys are discussed in relation to their projected applications as fast reactor fuels. Equilibrium diagrams, transformation kinetics, and other pertinent data are presented for the uranium plus fissium'' element systems, e.g., uranium-ruthenium, uranium-rhodium, uraninum-palladium, and uraniummolybdenum-ruthenium. The properties covered include constitution phase diagrams, metallographic structure, physical and mechanicaly properties, transformation kinetics, crystallographic structure, thermal cycling, ad irradiation stability (where pertinent). Correlations between microstructure, heat treatment, and dimensional stability are emphasized, with particular reference to the U-2 wt.% Zr, U-5 wt.% Zr, and 1 1/2 wt.% Nb alloys. A discussion of the role of alloying and heattreatment in improving the dimensionaly stability and corrosion resistance of uraaium is presented, and an evaluation is made of the present status in attaining these objectives. (auth

Aspen Crown Dieback and Mortality on the Williams Ranger District, Kaibab National Forest, Arizona

Crown dieback and mortality of quaking or trembling aspen (Populus tremuloides) were extensive within pine-oak and mixed conifer forest types of the Williams Ranger District, Kaibab National Forest in northern Arizona. I collected data from 48 aspen sites to determine if predisposing site and stand factors and contributing damaging agents were associated with aspen crown dieback and mortality. Overstory aspen mortality averaged 50% by stems per hectare and 44% by basal area. Based upon univariate relationships, elevation was the most significant site factor related to both overstory aspen crown dieback (R2 = 0.15, P = 0.0069) and overstory aspen mortality (R2 = 0.24, P = 0.0004). The most significant stand factor related to crown dieback was live aspen density (R2 = 0.18, P = 0.0029), while percent conifer (R2 = 0.45, P \u3c 0.0001) was the most significant stand factor related to mortality. Canker diseases, wood-boring insects, and animal damages were common in the overstory size class. The significant damaging agents in relation to both overstory crown dieback and mortality were canker diseases (R2 = 0.13, P = 0.0123; R2 = 0.18, P = 0.0028, respectively) and wood-boring insects (R2 = 0.24, P = 0.0005; R2 = 0.56, P \u3c 0.0001, respectively). Sapling and tall sucker aspen mortality were high (\u3e 80 and 70%, respectively), while short sucker mortality was low (16%). Many sites did not have live aspen regeneration, therefore, sample sizes were low, and relationships were often inconclusive or weak. Animal damages and canker diseases were common in the sapling and tall sucker size classes. Only animal damages were common in the short sucker size class. Among damaging agents and regeneration size classes, the only significant univariate relationship found was between animal damages and short sucker aspen mortality (R2 = 0.15, P = 0.0198). Based on a negative exponential diameter distribution, there was lack of aspen recruitment in saplings and small diameter overstory stems. If high mortality and low recruitment continues, aspen stands will be replaced by conifer after larger, and presumably older, overstory aspen stems die. The multivariate relationships of overstory aspen crown dieback, overstory aspen mortality, and short sucker aspen mortality among site, stand, and damaging agent factors were explored using step-wise multiple regression. The significant multivariate associations with overstory aspen crown dieback were elevation (F1,44 = 16.38, P = 0.0002) and incidence of canker diseases (F1,44 = 15.02, P = 0.0004). The significant factors explaining the variation in overstory aspen mortality were forest type (F1,43 = 5.92, P = 0.0192), overstory percent conifer (F1,43 = 8.24, P = 0.0063), and incidence of canker diseases (F1,43 = 33.05, P \u3c 0.0001), and wood-boring insects (F1,43 = 33.29, P \u3c 0.0001). The significant factors explaining the variation in short sucker aspen mortality were slope (F1,31 = 4.90, P = 0.0344), short sucker percent conifer (F1,31 = 5.00, P = 0.0327), and incidence of animal damages (F1,31 = 6.85, P = 0.0136). According to previous research, ungulate herbivores contribute to aspen decline in northern Arizona by causing damage to aspen regeneration. Ungulate damages were common in all size classes (between 49 and 66%), but significant relationships were limited to short sucker aspen mortality. No data were collected from within ungulate exclosures in this study. Controlled experiments inside and outside of ungulate exclosures are needed to determine the impact of ungulates

THE URANIUM-RICH END OF THE URANIUM-ZIRCONIUM SYSTEM. Final Report- Metallurgy Program 3.1.3.

The uranium-rich end of the uranium-zirconium alloy system was reinvestigated. The solubilities of zirconium in alpha and beta uranium were found to be 0.21 wt% at 662 deg C and 0.41 wt% at 693 deg C, respectively. The monotectoid decomposition of gamma /sub 1/ at 693 deg C and the eutectoid decomposition of t 662 deg C were confirmed. For alloys containing less than 150 ppm of oxygen by weight, the gamma /sub 1/ plus gamma /sub 2/ phase region boundaries were located at 4.5 and 22.0 wt% zirconium at the monotectoid temperature. Data are given which indicate that oxygen concentrations ranging from 160 to 355 ppm by weight have a marked effect on phase relations in the area of the gamma /sub 1/ plus gamma /sub 2/ phase region. (auth