Development of a thermal and structural analysis procedure for cooled radial turbines

A procedure for computing the rotor temperature and stress distributions in a cooled radial turbine are considered. Existing codes for modeling the external mainstream flow and the internal cooling flow are used to compute boundary conditions for the heat transfer and stress analysis. The inviscid, quasi three dimensional code computes the external free stream velocity. The external velocity is then used in a boundary layer analysis to compute the external heat transfer coefficients. Coolant temperatures are computed by a viscous three dimensional internal flow cade for the momentum and energy equation. These boundary conditions are input to a three dimensional heat conduction code for the calculation of rotor temperatures. The rotor stress distribution may be determined for the given thermal, pressure and centrifugal loading. The procedure is applied to a cooled radial turbine which will be tested at the NASA Lewis Research Center. Representative results are given

Quantum paramagnetic ground states on the honeycomb lattice and field-induced transition to N\'eel order

Motivated by recent experiments on Bi$_3$Mn$_4$O$_{12}$(NO$_3$), and a broader interest arising from numerical work on the honeycomb lattice Hubbard model, we have studied the effect of a magnetic field on honeycomb lattice spin models with quantum paramagnetic ground states. For a model with frustrating second-neighbor exchange, $J_2$, we use a Lindemann-like criterion within spin wave theory to show that N\'eel order melts beyond a critical $J_2$. The critical $J_2$ increases with a magnetic field, implying the existence of a field-induced paramagnet-N\'eel transition over a range of $J_2$. We also study bilayer model using a spin-$S$ generalization of bond operator mean field theory. We show that there is a N\'eel-dimer transition for various spin values with increasing bilayer coupling, and that the resulting interlayer dimer state undergoes a field induced transition into a state with transverse N\'eel order. Finally, we study a spin-3/2 model which interpolates between the Heisenberg model and the Affleck-Kennedy-Lieb-Tasaki (AKLT) parent Hamiltonian. Using exact diagonalization, we compute the fidelity susceptibility to locate the Neel-AKLT quantum critical point, obtain the spin gap of the AKLT parent Hamiltonian, and argue that AKLT state also undergoes field-induced Neel ordering.Comment: 8 pages, revised longer version of arXiv:1012.0316. Corrected factor of 2 error in Eq.[16], replotted Fig.[4] and revised the critical $J_c/J_1$ needed to stabilize interlayer dimer state. We thank S. V. Isakov for discussions which uncovered this erro

USE OF SURFACE GEOPHYSICAL TECHNIQUES TO LOCATE A KARST CONDUIT IN THE CANE RUN - ROYAL SPRING BASIN, KENTUCKY

Groundwater flow in karst terrains is difficult to map because it can be concentrated through conduits that do not necessarily coincide with the surface features. We applied electrical resistivity (ER) and self-potential (SP) techniques at three sites to locate an inferred trunk conduit feeding a major spring in the Inner Bluegrass region of Kentucky. Royal Spring is the primary water supply for the city of Georgetown; the upper part of its basin coincides with the Cane Run watershed. ER and SP profiles were perpendicular to the inferred trunk conduit orientation. ER profiles (972 m total length) were measured using a dipole–dipole electrode configuration with 2- to 3-m spacing. SP measurements were taken along those ER lines and an additional test profile (230 m) using one stationary reference electrode and another roving electrode at a fixed interval. The low resistivity of water in the conduit, as compared to the high background resistivity of limestone bedrock, is the ER exploration target. A negative SP anomaly corresponds to a low ER anomaly for most of the profiles, but a few are not comparable. Five of seven SP profiles measured over a period of several months were found to be reproducible. Although the overall trends of the final SP profiles for different dates were similar, the SP magnitudes varied with the amount of precipitation and the average soil temperature. The low-resistivity anomalies in the 2D inverted sections and corresponding negative SP anomalies could be water-filled conduits, although mud-filled voids encountered during drilling suggest that these may be tributary conduits rather than the trunk conduit

SPATIO-TEMPORAL VARIABILITY IN GROUNDWATER DISCHARGE AND CONTAMINANT FLUXES ALONG A CHANNELIZED STREAM IN WESTERN KENTUCKY

Spatio-temporal variability in groundwater discharge and contaminant fluxes along a channelized stream in western Kentucky Surface and groundwater discharges and contaminant fluxes can vary with time and space depending upon the hydrogeological processes and geological setting of the area of interest. This study examined a ~300-m-long, channelized reach of a first-order perennial stream, Little Bayou Creek, in the Coastal Plain of far western Kentucky during the period October 2010–February 2012. Along the study reach, springs discharge groundwater contaminated by the chlorinated organic compound trichloroethene (TCE) and radionuclide technetium-99 (99Tc) released as a result of past activities at the U.S. Department of Energy’s Paducah Gaseous Diffusion Plant. The study addressed variability in groundwater discharge patterns and contaminant concentrations at various timescales (seasonal, annual, and decadal) and the extent to which the discharge sites are spatially persistent. Understanding patterns of groundwater discharge along a stream can be important for assessing the fate and transport of aqueous contaminants. Groundwater discharge was estimated during baseflow conditions using different mass-balance approaches, including velocity-area and dye-dilution gauging. Discharge fluctuated seasonally but typically increased downstream, indicating the entire study reach to be gaining throughout the year. Discharge rates of individual springs also fluctuated seasonally. Tracer test data were utilized to model flow and transient storage along the reach using the USGS software OTIS-P. Cross-sectional area determined from OTIS-P was similar to that measured by velocity-area gauging. Reach area-normalized discharge fluxes were comparable to values determined by Darcy’s law calculations from a pair of monitoring wells at the downstream end of the study reach. Temperature data acquired from probing along grids in winter and summer, from fiber-optic sensing along the reach in autumn, and from data-loggers and manual measurements in springs were used to delineate focused discharge locations. Comparison of temperature-probing results with prior studies indicated that locations of some springs persisted over a decade, whereas other springs emerged and disappeared. Because the stream is located in unlithified sediments, discharge rates of springs appear to fluctuate with soil piping and collapse along joints in fractured clay. Contaminant concentrations in springs decreased downstream along the reach and were lower than observed during September 1999 – May 2001. The continued occurrence of dissolved oxygen and the absence of TCE daughter products in springs suggest that the decrease in TCE concentrations resulted from the installation of upgradient extraction wells, rather than from intrinsic reductive degradation. KEYWORDS: Contaminant fluxes, trichloroethene, technetium-99, baseflow, temperature probing

Effects on LDEF exposed copper film and bulk

Two forms of copper were exposed to the Long Duration Exposure Facility (LDEF) Mission 1 environment: a copper film, initially 74.2 plus or minus 1.1 nm thick sputter coated on a fused silica flat and a bulk piece of oxygen-free, high conductivity (OFHC) copper. The optical density of the copper film changed from 1.33 to 0.70 where exposed, and the film thickness increased to 106.7 plus or minus 0.5 nm where exposed. The exposed area appears purple by reflection and green by transmission for the thin film and maroon color for the bulk copper piece. The exposed areas increased in thickness, but only increase in the thickness of the thin film sample could be readily measured. The increase in film thickness is consistent with the density changes occurring during conversion of copper to an oxide. However, we have not been able to confirm appreciable conversion to an oxide by x-ray diffraction studies. We have not yet subjected the sample to e-beams or more abusive investigations out of concern that the film might be modified

The interaction of atomic oxygen with copper: An XPS, AES, XRD, optical transmission, and stylus profilometry study

The University of Alabama in Huntsville (UAH) experiment A-0114 was designed to study the reaction of material surfaces with low earth orbits (LEO) atmospheric oxygen. The experiment contained 128 one-inch circular samples; metals, polymers, carbons, and semiconductors. Half of these samples were exposed on the front of the Long Duration Exposure Facility (LDEF) and remaining on the rear. Among metal samples, copper has shown some interesting new results. There were two forms of copper samples: a thin film sputter-coated on fused silica and a solid piece of OFHC copper. They were characterized by x-ray and Auger electron spectroscopies, x-ray diffraction, and high resolution profilometry. Cu 2p core level spectra were used to demonstrate the presence of Cu2O and CuO and to determine the oxidation states

Lenalidomide-based combined therapy induced alterations in serum proteins of multiple myeloma patient: a follow-up case report and overview of the literature

Aim : Multiple myeloma (MM) is a malignant neoplasm of plasma cells (PC) derived from the bone marrow (BM) origin. The present case report was aimed to monitor the efficiency of lenalidomide-based combined therapy (LBCT) induced alterations in serum proteins of 42-year-old female MM patient. Besides, in the context of case report we also present an overview of the literature describing LBCT. Study design: Serum protein electrophoresis (SPEP) was performed in three visits (V1-V3) to monitor the disease status of the patient and her treatment response to LBCT. Level of monoclonal protein (M-protein) was measured through cellulose acetate zone electrophoresis and quantified by densitometer in follow-up investigations after therapy intervals. Results: A significant reduction of M-protein in γ-globulin region was observed (P < 0.007) after receiving LBCT. However, the condition depicted hyper γ-globulinemia. β-globulin (P < 0.002) and α2-globulin(P < 0.047) was suppressed from the initial visit and subsequent follow-up also indicated the status of hypoglobulinaemia. Although, serum albumin level was found to be increased after therapy (P < 0.016), hypoalbuminaemia was also noticed before and after LBCT. Conclusion: On the basis of this case report and pertinent literature, we conclude that LBCT is more efficient in the treatment of MM and has significant role in serum protein alterations especially in the reduction of M-protein in the MM patients