Liquid metal magnetohydrodynamics (LMMHD) technology transfer feasibility study. Volume 1: Summary

The potential application of liquid metal magnetohydrodynamics (LMMHD) to central station utility power generation through the period to 1990 is examined. Included are: (1) a description of LMMHD and a review of its development status, (2) LMMHD preliminary design for application to central station utility power generation, (3) evaluation of LMMHD in comparison with conventional and other advanced power generation systems and (4) a technology development plan. One of the major conclusions found is that the most economic and technically feasible application of LMMHD is a topping cycle to a steam plant, taking advantage of high temperatures available but not usable by the steam cycle

Liquid metal magnetohydrodynamics (LMMHD) technology transfer feasibility study. Volume 2: Appendixes

For abstract, see N74-13466

Evaluation of AIS Data for Agronomic and Rangeland Vegetation: Preliminary Results for August 1984 Flight over Nebraska Sandhills Agricultural Laboratory

Since 1978 scientists from the Center for Agricultural Meteorology and Climatology at the University of Nebraska have been conducting research at the Sandhills Agricultural Laboratory on the effects of water stress on crop growth, development and yield using remote sensing techniques. We have been working to develop techniques, both remote and ground-based, to monitor water stress, phenological development, leaf area, phytomass production and grain yields of corn, soybeans and sorghum. Because of the sandy soils and relatively low rainfall at the site it is an excellent location to study water stress without the necessity of installing expensive rainout shelters. The primary objectives of research with the airborne imaging spectrometer (AIS) data collected during an August 1984 flight over the Sandhills Agricultural Laboratory are to evaluate the potential of using AIS to: (1) discriminate crop type; (2) to detect subtle architectural differences that exist among different cultivars or hybrids of agronomic crops; (3) to detect and quantify, if possible, the level of water stress imposed on the crops; and (4) to evaluate leaf area and biomass differences for different crops

A Comparison of Photointerpretive and Digital Production Methods for Four Key Remote Sensing-Based Information Products

No abstract availabl

Solution to the problem of the poor cyclic fatigue resistance of bulk metallic glasses

The recent development of metallic glass-matrix composites represents a particular milestone in engineering materials for structural applications owing to their remarkable combination of strength and toughness. However, metallic glasses are highly susceptible to cyclic fatigue damage, and previous attempts to solve this problem have been largely disappointing. Here, we propose and demonstrate a microstructural design strategy to overcome this limitation by matching the microstructural length scales (of the second phase) to mechanical crack-length scales. Specifically, semisolid processing is used to optimize the volume fraction, morphology, and size of second-phase dendrites to confine any initial deformation (shear banding) to the glassy regions separating dendrite arms having length scales of ≈2 μm, i.e., to less than the critical crack size for failure. Confinement of the damage to such interdendritic regions results in enhancement of fatigue lifetimes and increases the fatigue limit by an order of magnitude, making these “designed” composites as resistant to fatigue damage as high-strength steels and aluminum alloys. These design strategies can be universally applied to any other metallic glass systems

Vitrification and determination of the crystallization time scales of the bulk-metallic-glass-forming liquid Zr58.5Nb2.8Cu15.6Ni12.8Al10.3

The crystallization kinetics of Zr58.5Nb2.8Cu15.6Ni12.8Al10.3 were studied in an electrostatic levitation (ESL) apparatus. The measured critical cooling rate is 1.75 K/s. Zr58.5Nb2.8Cu15.6Ni12.8Al10.3 is the first bulk-metallic-glass-forming liquid that does not contain beryllium to be vitrified by purely radiative cooling in the ESL. Furthermore, the sluggish crystallization kinetics enable the determination of the time-temperature-transformation (TTT) diagram between the liquidus and the glass transition temperatures. The shortest time to reach crystallization in an isothermal experiment; i.e., the nose of the TTT diagram is 32 s. The nose of the TTT diagram is at 900 K and positioned about 200 K below the liquidus temperature

Biomarker and isotopic trends in a Permian-Triassic sedimentary section at Kap Stosch, Greenland

We report a geochemical study of a composite sedimentary section that captures the Permian-Triassic (PT) transition at Kap Stosch, East Greenland. The samples were from the original paleontological collection of early PT researchers. The rocks, which include samples from four proximal outcrop localities, were deposited during the Late Permian and Early Triassic at the margin of the Boreal Sea with a depositional hiatus and erosional event of unknown duration. Bulk geochemical measurements for most of the samples show good correlation between S2 and TOC% which, combined with low Tmax values, indicate that the organic matter (OM) that formed contemporaneously with sediment deposition is of relatively low maturity. Significant changes through the PT transition include a pronounced switch in the δ13C of TOC from high values near -24% to lower values averaging 32%, that is matched by a significant increase in the hydrogen index (HI) of the kerogen. The Permian samples containing 13C enriched OM also have low Rock-Eval HI values and anomalous pyrograms, indicating that the kerogen is heterogeneous in terms of source and maturity, as confirmed by microscopic analysis of the kerogen concentrates.Samples from the Permian section contain an abundance of black angular fragments of woody tissue in addition to gymnosperm pollen and spinose acritarchs of the Vittatina-Association (Balme, B., 1979. Palynology of Permian-Triassic boundary beds at Kap Stosch. Meddeleleser om Gronland 200, 1-36). In contrast, black woody tissue is rare in samples from the Early Triassic section with well preserved gymnosperm and lycopod pollen and spores of the Protohaploxypinus and Taeniaesporites associations. Biomarkers indicate moderate maturity for Permian samples, with the C27 sterane 20S/(20S + 20R), C31 homohopane 22S/(22S + 22R) ratio and Ts/(Ts + Tm) values all being higher than those for Triassic sediments. The marked switch in maturity indicators across the PT transition suggests an unconformity consistent with palynological observations. The pristane/phytane values are low and the homohopane index values high, indicating that anoxic conditions prevailed throughout deposition of the sediments.Additionally, markers of photic zone euxinia (i.e. isorenieratane, crocetane and 2,3,6-aryl isoprenoids) were present in all samples and all show maximum abundance closest to the PT transition. The C33 n-alkyl cyclohexane, a potential event marker for the onset of the biotic crisis in the Late Permian, was found in samples at, and immediately following, the paleontological PT transition. Despite the distinct change in lithology across the PT transition, the redox and Chlorobi-derived biomarkers indicate that photic zone euxinic conditions prevailed throughout the deposition of the Kap Stosch sedimentary sequence

Observations of the 5‐day wave in the mesosphere and lower thermosphere

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94851/1/grl7954.pd

Program on Earth Observation Data Management Systems (EODMS)

An assessment was made of the needs of a group of potential users of satellite remotely sensed data (state, regional, and local agencies) involved in natural resources management in five states, and alternative data management systems to satisfy these needs are outlined. Tasks described include: (1) a comprehensive data needs analysis of state and local users; (2) the design of remote sensing-derivable information products that serve priority state and local data needs; (3) a cost and performance analysis of alternative processing centers for producing these products; (4) an assessment of the impacts of policy, regulation and government structure on implementing large-scale use of remote sensing technology in this community of users; and (5) the elaboration of alternative institutional arrangements for operational Earth Observation Data Management Systems (EODMS). It is concluded that an operational EODMS will be of most use to state, regional, and local agencies if it provides a full range of information services -- from raw data acquisition to interpretation and dissemination of final information products