Science.gov

Sample records for multiple triaxial sd

  1. Multiple triaxial bands in 138Nd

    NASA Astrophysics Data System (ADS)

    Petrache, C. M.; Ragnarsson, I.; Ma, Hai-Liang; Leguillon, R.; Zerrouki, T.; Bazzacco, D.; Lunardi, S.

    2015-02-01

    High-spin states in 138Nd were investigated by using the 48Ca+94Zr reaction and γ -ray coincidences were acquired with the GASP spectrometer. A rich level scheme was developed including 14 new bands of quadrupole transitions at very high spins. Linking transitions connecting 11 high-spin bands to low-energy states have been observed. Calculations based on the cranked Nilsson-Strutinsky formalism have been used to assign configurations to the observed bands. The main result of these calculations is that all 14 bands exhibit a stable triaxial deformation up to the highest observed spins, giving strong support to the existence of a triaxial minimum with normal deformation and positive asymmetry parameter in nuclei with a few holes in the N =82 shell closure.

  2. Chiral Bands and Triaxiality

    SciTech Connect

    Petrache, C.M.

    2004-02-27

    The results obtained with the GASP array in the A=130 mass region are reviewed, emphasizing the discovery excited highly-deformed bands and their decay out, the study of the odd-odd Pr nuclei up to high spins, the discovery of stable triaxial bands in Nd nuclei close to the N=82 shell closure. The very recent studies of nuclei near the proton drip line are described. A discussion of the origin of the various doublet bands observed in odd-odd nuclei of the A=130 mass region is presented.

  3. Triaxial Probe Magnetic Data Analysis

    NASA Technical Reports Server (NTRS)

    Shultz, Kimberly; Whittlesey, Albert; Narvaez, Pablo

    2007-01-01

    The Triaxial Magnetic Moment Analysis software uses measured magnetic field test data to compute dipole and quadrupole moment information from a hardware element. It is used to support JPL projects needing magnetic control and an understanding of the spacecraft-generated magnetic fields. Evaluation of the magnetic moment of an object consists of three steps: acquisition, conditioning, and analysis. This version of existing software was extensively rewritten for easier data acquisition, data analysis, and report presentation, including immediate feedback to the test operator during data acquisition. While prior JPL computer codes provided the same data content, this program has a better graphic display including original data overlaid with reconstructed results to show goodness of fit accuracy and better appearance of the report graphic page. Data are acquired using three magnetometers and two rotations of the device under test. A clean acquisition user interface presents required numeric data and graphic summaries, and the analysis module yields the best fit (least squares) for the magnetic dipole and/or quadrupole moment of a device. The acquisition module allows the user to record multiple data sets, selecting the best data to analyze, and is repeated three times for each of the z-axial and y-axial rotations. In this update, the y-axial rotation starting position has been changed to an option, allowing either the x- or z-axis to point towards the magnetometer. The code has been rewritten to use three simultaneous axes of magnetic data (three probes), now using two "rotations" of the device under test rather than the previous three rotations, thus reducing handling activities on the device under test. The present version of the software gathers data in one-degree increments, which permits much better accuracy of the fit ted data than the coarser data acquisition of the prior software. The data-conditioning module provides a clean data set for the analysis module

  4. The Triaxial Klystron

    SciTech Connect

    Pasour, J.; Smithe, D.; Friedman, M.

    1999-05-01

    We describe a high-power, annular beam klystron, the Triaxial Klystron, that promises high efficiency at GW power levels and frequencies up to X band. Higher frequency operation should be possible at reduced power levels. The device consists of a thin annular electron beam propagating in an annular drift region, with cavity structures located inside and outside the beam. So long as the width of the drift region is less than half a wavelength (to cut off TM modes), the beam diameter can be as large as necessary to accommodate the required current and to reduce the RF surface fields to tolerable levels. Beam transport and stability are also facilitated in the annular channel. Simulations at X-band (using MRC{close_quote}s particle-in-cell code, MAGIC) show strong beam bunching and efficient energy extraction from specially designed radial cavity structures. Initial experiments at the Naval Research Laboratory have demonstrated transport of a 16-kA, 400-keV beam over a distance of {approximately}1 m with no evidence of instability or asymmetry. Strong bunching of such a beam has been produced at X band using a coaxially-driven input cavity and a multi-gap buncher cavity structure. The peak-to-peak modulated current amplitude from this simple structure exceeds the injected current amplitude and is stable throughout the 150 nsec pulse. {copyright} {ital 1999 American Institute of Physics.}

  5. Transgenerational Effects of Di (2-Ethylhexyl) Phthalate in the Male CRL:CD(SD) Rat: Added Value of Assessing Multiple Offspring per Litter

    PubMed Central

    Gray, Leon Earl; Barlow, Norman J.; Howdeshell, Kembra L.; Ostby, Joseph S.; Furr, Johnathan R.; Gray, Clark L.

    2009-01-01

    In the rat, some phthalates alter sexual differentiation at relatively low dosage levels by altering fetal Leydig cell development and hormone synthesis, thereby inducing abnormalities of the testis, gubernacular ligaments, epididymis, and other androgen-dependent tissues. In order to define the dose-response relationship between di(2-ethylhexyl) phthalate (DEHP) and the Phthalate Syndrome of reproductive alterations in F1 male rats, Sprague-Dawley (SD) rat dams were dosed by gavage from gestational day 8 to day 17 of lactation with 0, 11, 33, 100, or 300 mg/kg/day DEHP (71–93 males per dose from 12 to 14 litters per dose). Some of the male offspring continued to be exposed to DEHP via gavage from 18 days of age to necropsy at 63–65 days of age (PUB cohort; 16–20/dose). Remaining males were not exposed after postnatal day 17 (in utero-lactational [IUL] cohort) and were necropsied after reaching full maturity. Anogenital distance, sperm counts and reproductive organ weights were reduced in F1 males in the 300 mg/kg/day group and they displayed retained nipples. In the IUL cohort, seminal vesicle weight also was reduced at 100 mg/kg/day. In contrast, serum testosterone and estradiol levels were unaffected in either the PUB or IUL cohorts at necropsy. A significant percentage of F1 males displayed one or more Phthalate Syndrome lesions at 11 mg/kg/day DEHP and above. We were able to detect effects in the lower dose groups only because we examined all the males in each litter rather than only one male per litter. Power calculations demonstrate how using multiple males versus one male/litter enhances the detection of the effects of DEHP. The results at 11 mg/kg/day confirm those reported from a National Toxicology Program multigenerational study which reported no observed adverse effect levels-lowest observed adverse effect levels of 5 and 10 mg/kg/day DEHP, respectively, via the diet. PMID:19482887

  6. Algebraic Realization of the Triaxial Rotor Dynamics

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Li, Q. Y.; Zuo, Y.; Wang, X. X.

    A mapping from the triaxial rotor to the SU(3) limit description in the interacting boson model is established. A comparison between the triaxial dynamics generated from the triaxial rotor and those from the IBM image has been made through a numerical example, and the results indicate that the mapping scheme works very well.

  7. Calibration of triaxial fluxgate gradiometer

    SciTech Connect

    Vcelak, Jan

    2006-04-15

    The description of simple and fast calibration procedures used for double-probe triaxial fluxgate gradiometer is provided in this paper. The calibration procedure consists of three basic steps. In the first step both probes are calibrated independently in order to reach constant total field reading in every position. Both probes are numerically aligned in the second step in order that the gradient reading is zero in homogenous magnetic field. The third step consists of periodic drift calibration during measurement. The results and detailed description of each calibration step are presented and discussed in the paper. The gradiometer is finally verified during the detection of the metal object in the measuring grid.

  8. Dynamics of gas disks in triaxial galaxies

    SciTech Connect

    Steiman-Cameron, T.Y.

    1984-01-01

    Increasing evidence has accumulated since the mid 1970's arguing that many, if not all, undisturbed galaxies may have triaxial mass distributions. The steady state configurations (preferred planes) of gas disks in triaxial galaxies with static and rotating surface figures is determined. In addition, the evolution of a gas disk as it settles into the steady state is followed for both axisymmetric and triaxial galaxies. Observational tests are provided for triaxial galactic geometry and give more accurate measures of settling times than those previously published. The preferred planes for gas disks in static and tumbling triaxial galaxies are determined using an analytic method derived from celestial mechanics. The evolution of gas disks which are not in the steady state is followed using numerical methods.

  9. NDPC-SD Data Probes Worksheet

    ERIC Educational Resources Information Center

    National Dropout Prevention Center for Students with Disabilities, 2011

    2011-01-01

    This worksheet from the National Dropout Prevention Center for Students with Disabilities (NDPC-SD) is an optional tool to help schools organize multiple years of student and program data for the purpose of identifying school-completion needs that can be addressed through the implementation of research-based interventions. It is designed for use…

  10. The LMF triaxial MITL voltage adder system

    SciTech Connect

    Mazarakis, M.G.; Smith, D.L.; Bennett, L.F.; Lockner, T.R.; Olson, R.E.; Poukey, J.W.

    1992-12-31

    The light-ion microfusion driver design consists of multiple accelerating modules fired in coincidence and sequentially in order to provide the desired ion energy, power pulse shape and energy deposition uniformity on an Inertial Confinement Fusion (ICF) target. The basic energy source is a number of Marx generators which, through the appropriate pulse power conditioning, provide the necessary voltage pulse wave form to the accelerating gaps or feeds of each module. The cavity gaps are inductively isolated, and the voltage addition occurs in the center conductor of the voltage adder which is the positive electrode while the electrons of the sheath flow closer to the outer cylinder which is the magnetically insulated cathode electrode. Each module powers a separate two-stage extraction diode which provides a low divergence ion beam. In order to provide the two separate voltage pulses required by the diode, a triaxial adder system is designed for each module. The voltage addition occurs in two separate MITLs. The center hollow cylinder (anode) of the second MITL also serves as the outer cathode electrode for the extension of the first voltage adder MITL. The voltage of the second stage is about twice that of the first stage. The cavities are connected in series to form the outer cylinder of each module. The accelerating modules are positioned radially in a symmetrical way around the fusion chamber. A preliminary conceptual design of the LMF modules with emphasis on the voltage adders and extension MITLs will be presented and discussed.

  11. Superdeformed and Triaxial States in 42Ca

    NASA Astrophysics Data System (ADS)

    Hadyńska-KlÈ©k, K.; Napiorkowski, P. J.; Zielińska, M.; Srebrny, J.; Maj, A.; Azaiez, F.; Valiente Dobón, J. J.; Kicińska-Habior, M.; Nowacki, F.; Naïdja, H.; Bounthong, B.; Rodríguez, T. R.; de Angelis, G.; Abraham, T.; Anil Kumar, G.; Bazzacco, D.; Bellato, M.; Bortolato, D.; Bednarczyk, P.; Benzoni, G.; Berti, L.; Birkenbach, B.; Bruyneel, B.; Brambilla, S.; Camera, F.; Chavas, J.; Cederwall, B.; Charles, L.; Ciemała, M.; Cocconi, P.; Coleman-Smith, P.; Colombo, A.; Corsi, A.; Crespi, F. C. L.; Cullen, D. M.; Czermak, A.; Désesquelles, P.; Doherty, D. T.; Dulny, B.; Eberth, J.; Farnea, E.; Fornal, B.; Franchoo, S.; Gadea, A.; Giaz, A.; Gottardo, A.; Grave, X.; GrÈ©bosz, J.; Görgen, A.; Gulmini, M.; Habermann, T.; Hess, H.; Isocrate, R.; Iwanicki, J.; Jaworski, G.; Judson, D. S.; Jungclaus, A.; Karkour, N.; Kmiecik, M.; Karpiński, D.; Kisieliński, M.; Kondratyev, N.; Korichi, A.; Komorowska, M.; Kowalczyk, M.; Korten, W.; Krzysiek, M.; Lehaut, G.; Leoni, S.; Ljungvall, J.; Lopez-Martens, A.; Lunardi, S.; Maron, G.; Mazurek, K.; Menegazzo, R.; Mengoni, D.; Merchán, E.; MÈ©czyński, W.; Michelagnoli, C.; Mierzejewski, J.; Million, B.; Myalski, S.; Napoli, D. R.; Nicolini, R.; Niikura, M.; Obertelli, A.; Özmen, S. F.; Palacz, M.; Próchniak, L.; Pullia, A.; Quintana, B.; Rampazzo, G.; Recchia, F.; Redon, N.; Reiter, P.; Rosso, D.; Rusek, K.; Sahin, E.; Salsac, M.-D.; Söderström, P.-A.; Stefan, I.; Stézowski, O.; Styczeń, J.; Theisen, Ch.; Toniolo, N.; Ur, C. A.; Vandone, V.; Wadsworth, R.; Wasilewska, B.; Wiens, A.; Wood, J. L.; Wrzosek-Lipska, K.; ZiÈ©bliński, M.

    2016-08-01

    Shape parameters of a weakly deformed ground-state band and highly deformed slightly triaxial sideband in 42Ca were determined from E 2 matrix elements measured in the first low-energy Coulomb excitation experiment performed with AGATA. The picture of two coexisting structures is well reproduced by new state-of-the-art large-scale shell model and beyond-mean-field calculations. Experimental evidence for superdeformation of the band built on 02+ has been obtained and the role of triaxiality in the A ˜40 mass region is discussed. Furthermore, the potential of Coulomb excitation as a tool to study superdeformation has been demonstrated for the first time.

  12. Exotic rotations and triaxiality in Nd nuclei

    NASA Astrophysics Data System (ADS)

    Petrache, C. M.

    2015-11-01

    We have recently studied the Nd nuclei up to very high spins and identified a multitude of bands which are interpreted as the manifestation of a nucleus with stable triaxial shape, presenting various types of collective motion: tilted axis and principal axis rotation, wobbling motion, chiral bands. Seniority isomers built on nearly spherical shapes up to very high spins, surrounded by coexisting triaxial bands, have also been observed. The new results obtained from the systematics of the high-spin bands of Nd nuclei are discussed.

  13. Mixing of Triaxial and Intruder Configurations in 72,76Ge Studied via Multistep Coulomb Excitation

    NASA Astrophysics Data System (ADS)

    Ayangeakaa, A. D.; Janssens, R. V. F.; Anl Collaboration; Llnl Collaboration; Lbnl Collaboration; U. Of Maryland Collaboration; Csnsm Collaboration

    2015-10-01

    The low-lying states in even-even Ge isotopes have been a subject of intense scrutiny for many years due to the inherent challenge of interpreting their low-energy structure. While several explanations such as vibrational-rotational coupling, 2p-2h intruder mixing and shape coexistence have been proposed, none have been able to satisfactorily reproduce the properties of these low-lying excitations. Recent theoretical calculations have, however, emphasized the importance of the triaxial degree of freedom and, indeed, 76Ge is proposed to exhibit static triaxiality. In this study, the electromagnetic properties of low-lying states in 72,76Ge were investigated via sub-barrier multiple Coulomb excitation with GRETINA and CHICO-2. In the case of 72Ge, the extracted matrix elements seem to agree with the shape coexistence interpretation between the 01+ and 02+ states. However, significant mixing between the wavefunctions of these two states and triaxiality are required to reproduce the overall data. These results and calculations based on a triaxial rotor model with configuration mixing will be presented, and the role of triaxiality will be discussed. Preliminary results for 76Ge will also be highlighted. This work is supported by the DOE, Office of Science, Office of Nuclear Physics under Contract Number DE-AC02-06CH11357, and Grant No. DE-FG02-94ER40834 and DE-FG02-08ER41556.

  14. Rotational Kinematics and Torques for Triaxial Bodies: A Simple Derivation of Precession with Synchronous Locking

    NASA Astrophysics Data System (ADS)

    Newman, William I.

    2012-05-01

    Precession of the equinoxes and of satellite orbits for axisymmetric bodies is a celebrated part of the classical and orbital mechanics literature. The theory underlying the behavior of triaxial bodies, particularly when synchronous phase locking is present, has proven to be difficult to evaluate and controversial. We perform a first-principles derivation where we incorporate triaxial geometry into the analysis using a straightforward description of the configuration. We calculate the effect of triaxiality and phase locking upon precession rates by using multiple time scales techniques. This is required to make possible the direct numerical integration of the kinematic equations of motion over solar system time scales. In so doing, we provide a simple derivation of the time-averaged gravitational potential and the associated torque that drives precession, and resolve an outstanding controversy emerging from its calculation.

  15. Miniature piezoelectric triaxial accelerometer measures cranial accelerations

    NASA Technical Reports Server (NTRS)

    Deboo, G. J.; Rogallo, V. L.

    1966-01-01

    Tiny triaxial accelerometer whose sensing elements are piezoelectric ceramic beams measures human cranial accelerations when a subject is exposed to a centrifuge or other simulators of g environments. This device could be considered for application in dental, medical, and automotive safety research.

  16. Burst Testing of Triaxial Braided Composite Tubes

    NASA Technical Reports Server (NTRS)

    Salem, J. A.; Bail, J. L.; Wilmoth, N. G.; Ghosn, L. J.; Kohlman, L. W.; Roberts, G. D.; Martin, R. E.

    2014-01-01

    Applications using triaxial braided composites are limited by the materials transverse strength which is determined by the delamination capacity of unconstrained, free-edge tows. However, structural applications such as cylindrical tubes can be designed to minimize free edge effects and thus the strength with and without edge stresses is relevant to the design process. The transverse strength of triaxial braided composites without edge effects was determined by internally pressurizing tubes. In the absence of edge effects, the axial and transverse strength were comparable. In addition, notched specimens, which minimize the effect of unconstrained tow ends, were tested in a variety of geometries. Although the commonly tested notch geometries exhibited similar axial and transverse net section failure strength, significant dependence on notch configuration was observed. In the absence of unconstrained tows, failure ensues as a result of bias tow rotation, splitting, and fracture at cross-over regions.

  17. Superdeformed and Triaxial States in ^{42}Ca.

    PubMed

    Hadyńska-Klȩk, K; Napiorkowski, P J; Zielińska, M; Srebrny, J; Maj, A; Azaiez, F; Valiente Dobón, J J; Kicińska-Habior, M; Nowacki, F; Naïdja, H; Bounthong, B; Rodríguez, T R; de Angelis, G; Abraham, T; Anil Kumar, G; Bazzacco, D; Bellato, M; Bortolato, D; Bednarczyk, P; Benzoni, G; Berti, L; Birkenbach, B; Bruyneel, B; Brambilla, S; Camera, F; Chavas, J; Cederwall, B; Charles, L; Ciemała, M; Cocconi, P; Coleman-Smith, P; Colombo, A; Corsi, A; Crespi, F C L; Cullen, D M; Czermak, A; Désesquelles, P; Doherty, D T; Dulny, B; Eberth, J; Farnea, E; Fornal, B; Franchoo, S; Gadea, A; Giaz, A; Gottardo, A; Grave, X; Grȩbosz, J; Görgen, A; Gulmini, M; Habermann, T; Hess, H; Isocrate, R; Iwanicki, J; Jaworski, G; Judson, D S; Jungclaus, A; Karkour, N; Kmiecik, M; Karpiński, D; Kisieliński, M; Kondratyev, N; Korichi, A; Komorowska, M; Kowalczyk, M; Korten, W; Krzysiek, M; Lehaut, G; Leoni, S; Ljungvall, J; Lopez-Martens, A; Lunardi, S; Maron, G; Mazurek, K; Menegazzo, R; Mengoni, D; Merchán, E; Mȩczyński, W; Michelagnoli, C; Mierzejewski, J; Million, B; Myalski, S; Napoli, D R; Nicolini, R; Niikura, M; Obertelli, A; Özmen, S F; Palacz, M; Próchniak, L; Pullia, A; Quintana, B; Rampazzo, G; Recchia, F; Redon, N; Reiter, P; Rosso, D; Rusek, K; Sahin, E; Salsac, M-D; Söderström, P-A; Stefan, I; Stézowski, O; Styczeń, J; Theisen, Ch; Toniolo, N; Ur, C A; Vandone, V; Wadsworth, R; Wasilewska, B; Wiens, A; Wood, J L; Wrzosek-Lipska, K; Ziȩbliński, M

    2016-08-01

    Shape parameters of a weakly deformed ground-state band and highly deformed slightly triaxial sideband in ^{42}Ca were determined from E2 matrix elements measured in the first low-energy Coulomb excitation experiment performed with AGATA. The picture of two coexisting structures is well reproduced by new state-of-the-art large-scale shell model and beyond-mean-field calculations. Experimental evidence for superdeformation of the band built on 0_{2}^{+} has been obtained and the role of triaxiality in the A∼40 mass region is discussed. Furthermore, the potential of Coulomb excitation as a tool to study superdeformation has been demonstrated for the first time. PMID:27541463

  18. Inertial modes in a rotating triaxial ellipsoid

    PubMed Central

    Vantieghem, S.

    2014-01-01

    In this work, we present an algorithm that enables computation of inertial modes and their corresponding frequencies in a rotating triaxial ellipsoid. The method consists of projecting the inertial mode equation onto finite-dimensional bases of polynomial vector fields. It is shown that this leads to a well-posed eigenvalue problem, and hence, that eigenmodes are of polynomial form. Furthermore, these results shed new light onto the question whether the eigenmodes form a complete basis, i.e. whether any arbitrary velocity field can be expanded in a sum of inertial modes. Finally, we prove that two intriguing integral properties of inertial modes in rotating spheres and spheroids also extend to triaxial ellipsoids. PMID:25104908

  19. Tri-axial tactile sensing element

    NASA Astrophysics Data System (ADS)

    Castellanos-Ramos, Julián.; Navas-González, Rafael; Vidal-Verdú, F.

    2013-05-01

    A 13 x 13 square millimetre tri-axial taxel is presented which is suitable for some medical applications, for instance in assistive robotics that involves contact with humans or in prosthetics. Finite Element Analysis is carried out to determine what structure is the best to obtain a uniform distribution of pressure on the sensing areas underneath the structure. This structure has been fabricated in plastic with a 3D printer and a commercial tactile sensor has been used to implement the sensing areas. A three axis linear motorized translation stage with a tri-axial precision force sensor is used to find the parameters of the linear regression model and characterize the proposed taxel. The results are analysed to see to what extent the goal has been reached in this specific implementation.

  20. On the pairing effects in triaxial nuclei

    SciTech Connect

    Oudih, M. R.; Fellah, M.; Allal, N. H.

    2014-03-05

    Triaxial deformation effect on the pairing correlations is studied in the framework of the Skyrme Hartree-Fock-Bogoliubov theory. Quantities such as binding energy, gap parameter and particle-number fluctuation are considered in neutron-rich Mo isotopes. The results are compared with those of axially symmetric calculation and with available experimental data. The role played by the particle-number projection is outlined.

  1. SD46 Facilities and Capabilities

    NASA Technical Reports Server (NTRS)

    Ramachandran, N.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    The displays for the Materials Conference presents some of the facilities and capabilities in SD46 that can be useful to a prospective researcher from University, Academia or other government labs. Several of these already have associated personnel as principal and co-investigators on NASA peer reviewed science investigations. 1. SCN purification facility 2. ESL facility 3. Static and Dynamic magnetic field facility 4. Microanalysis facility 5. MSG Investigation - PFMI 6. Thermo physical Properties Measurement Capabilities.

  2. True triaxial testing of Castlegate sandstone.

    SciTech Connect

    Ingraham, M. D.; Holcomb, David Joseph; Issen, Kathleen A.

    2010-03-01

    Deformation bands in high porosity sandstone are an important geological feature for geologists and petroleum engineers; however, their formation is not fully understood. Axisymmetric compression, the common test for this material, is not sufficient to fully evaluate localization criteria. This study seeks to investigate the influence of the second principal stress on the failure and the formation of deformation bands in Castlegate sandstone. Experimental results from tests run in the axisymmetric compression stress state, as well as a stress state between axisymmetric compression and pure shear will be presented. Samples are tested using a custom triaxial testing rig at Sandia National Laboratories capable of applying stresses up to 400 MPa. Acoustic emissions are used to locate deformation bands should they not be visible on the specimen exterior. It is suspected that the second invariant of stress has a strong contribution to the failure mode and band formation. These results could have significant bearing on petroleum extraction as well as carbon dioxide sequestration.

  3. Low Noise Borehole Triaxial Seismometer Phase II

    SciTech Connect

    Kerr, James D; McClung, David W

    2006-11-06

    This report describes the preliminary design and the effort to date of Phase II of a Low Noise Borehole Triaxial Seismometer for use in networks of seismic stations for monitoring underground nuclear explosions. The design uses the latest technology of broadband seismic instrumentation. Each parameter of the seismometer is defined in terms of the known physical limits of the parameter. These limits are defined by the commercially available components, and the physical size constraints. A theoretical design is proposed, and a preliminary prototype model of the proposed instrument has been built. This prototype used the sensor module of the KS2000. The installation equipment (hole locks, etc.) has been designed and one unit has been installed in a borehole. The final design of the sensors and electronics and leveling mechanism is in process. Noise testing is scheduled for the last quarter of 2006.

  4. Orbits Around Black Holes in Triaxial Nuclei

    NASA Astrophysics Data System (ADS)

    Merritt, David; Vasiliev, Eugene

    2011-01-01

    We discuss the properties of orbits within the influence sphere of a supermassive black hole (BH), in the case that the surrounding star cluster is non-axisymmetric. There are four major orbit families; one of these, the pyramid orbits, have the interesting property that they can approach arbitrarily closely to the BH. We derive the orbit-averaged equations of motion and show that in the limit of weak triaxiality, the pyramid orbits are integrable: the motion consists of a two-dimensional libration of the major axis of the orbit about the short axis of the triaxial figure, with eccentricity varying as a function of the two orientation angles and reaching unity at the corners. Because pyramid orbits occupy the lowest angular momentum regions of phase space, they compete with collisional loss cone repopulation and with resonant relaxation (RR) in supplying matter to BHs. General relativistic advance of the periapse dominates the precession for sufficiently eccentric orbits, and we show that relativity imposes an upper limit to the eccentricity: roughly the value at which the relativistic precession time is equal to the time for torques to change the angular momentum. We argue that this upper limit to the eccentricity should also apply to evolution driven by RR, with potentially important consequences for the rate of extreme-mass-ratio inspirals in low-luminosity galaxies. In giant galaxies, we show that capture of stars on pyramid orbits can dominate the feeding of BHs, at least until such a time as the pyramid orbits are depleted; however this time can be of order a Hubble time.

  5. ORBITS AROUND BLACK HOLES IN TRIAXIAL NUCLEI

    SciTech Connect

    Merritt, David; Vasiliev, Eugene E-mail: eugvas@lpi.ru

    2011-01-10

    We discuss the properties of orbits within the influence sphere of a supermassive black hole (BH), in the case that the surrounding star cluster is non-axisymmetric. There are four major orbit families; one of these, the pyramid orbits, have the interesting property that they can approach arbitrarily closely to the BH. We derive the orbit-averaged equations of motion and show that in the limit of weak triaxiality, the pyramid orbits are integrable: the motion consists of a two-dimensional libration of the major axis of the orbit about the short axis of the triaxial figure, with eccentricity varying as a function of the two orientation angles and reaching unity at the corners. Because pyramid orbits occupy the lowest angular momentum regions of phase space, they compete with collisional loss cone repopulation and with resonant relaxation (RR) in supplying matter to BHs. General relativistic advance of the periapse dominates the precession for sufficiently eccentric orbits, and we show that relativity imposes an upper limit to the eccentricity: roughly the value at which the relativistic precession time is equal to the time for torques to change the angular momentum. We argue that this upper limit to the eccentricity should also apply to evolution driven by RR, with potentially important consequences for the rate of extreme-mass-ratio inspirals in low-luminosity galaxies. In giant galaxies, we show that capture of stars on pyramid orbits can dominate the feeding of BHs, at least until such a time as the pyramid orbits are depleted; however this time can be of order a Hubble time.

  6. Borehole Effects in Triaxial Induction Logging

    SciTech Connect

    Bertete-Aguirre, H; Cherkaev, E; Tripp, A

    2000-09-15

    Traditional induction tools use source arrays in which both receiving and transmitting magnetic dipoles are oriented along the borehole axis. This orientation has been preferred for traditional isotropic formation evaluation in vertical boreholes because borehole effects are minimized by the source-receiver-borehole symmetry. However, this source-receiver geometry tends to minimize the response of potentially interesting geological features? such as bed resistivity anisotropy and fracturing which parallels the borehole. Traditional uniaxial tool responses are also ambiguous in highly deviated boreholes in horizontally layered formations. Resolution of these features would be enhanced by incorporating one or more source transmitters that are perpendicular to the borehole axis. Although these transmitters can introduce borehole effects, resistive oil-based muds minimize borehole effects for horizontal source data collection and interpretation. However, the use of oil based muds is contraindicated in environmentally sensitive areas. For this reason, it is important to be able to assess the influence of conductive water based muds on the new generation of triaxial induction tools directed toward geothermal resource evaluation and to develop means of ameliorating any deleterious effects. The present paper investigates the effects of a borehole on triaxial measurements. The literature contains a great deal of work on analytic expressions for the EM response of a magnetic dipole contained in a borehole with possible invasion zones. Moran and Gianzero (1979) for example investigate borehole effects using such an expression. They show that for conductive borehole fluids, the borehole response can easily swamp the formation response for horizontal dipoles. This is also true when the source dipoles are enclosed in a resistive cavity, as shown by Howard (1981) using a mode match modeling technique.

  7. Behavior of compacted lunar simulants using new vacuum triaxial device

    NASA Technical Reports Server (NTRS)

    Desai, Chandra S.; Saadatmanesh, Hamid; Allen, Thomas

    1992-01-01

    The objectives of this study are to create a lunar simulant locally from a basaltic rock and to design and develop a vacuum triaxial test device that can permit testing of compacted lunar simulant under cyclic loading with different levels of initial vacuum. Triaxial testing is performed in the device itself without removing the compacted specimen. Preliminary constrained compression and triaxial shear tests are performed to identify effects of initial confinements and vacuums. The results are used to define deformation and strength parameters. At this time, vacuum levels up to 0.0001 are possible. The research can aid in the development of compacted materials for various construction applications.

  8. Comparison of physical activity energy expenditure in Japanese adolescents assessed by EW4800P triaxial accelerometry and the doubly labelled water method.

    PubMed

    Ishikawa-Takata, Kazuko; Kaneko, Kayoko; Koizumi, Kayo; Ito, Chinatsu

    2013-10-01

    The present study compared the accuracy of triaxial accelerometry and the doubly labelled water (DLW) method for measuring physical activity (PA) in Japanese adolescents. A total of sixty adolescents aged 12-15 years were analysed. The total energy expenditure (TEE) was measured over 7 d by the DLW method and with an EW4800P triaxial accelerometer (Panasonic Corporation). The measured (RMR)(m) and predicted RMR (RMR(p)) were 5·7 (SD 0·9) and 6·0 (SD 1·0) MJ/d, respectively. TEE measured by the DLW method and accelerometry using RMR(m) or RMR(p) were 11·0 (SD 2·6), 10·3 (SD 1·9), and 10·7 (SD 2·1) MJ/d, respectively. The PA levels (PAL) measured by the DLW method using RMR(m) or RMR(p) were 1·97 (SD 0·31) and 1·94 (SD 0·31) in subjects who exercised, and 1·85 (SD 0·27) and 1·74 (SD 0·29) in subjects who did not exercise. The percentage of body fat correlated significantly with the percentage difference between RMR(m) v. RMR(p), TEE, PA energy expenditure (PAEE) and PAL using RMR(p), and PAL using RMR(m) assessed by the DLW method and accelerometry. The present data showed that while accelerometry estimated TEE accurately, it did not provide the precise measurement of PAEE and PAL. The error in accelerometry was attributed to the prediction error of RMR and assessment in exercise. PMID:23544366

  9. In-Orbit Calibration of a SAMS Triaxial Sensor Head

    NASA Technical Reports Server (NTRS)

    Chestney, Louis S.; Sicker, Ronald J.

    1996-01-01

    This report describes the results of in orbit calibration data collected for a Space Acceleration Measurement System (SAMS) Triaxial Sensor Head (TS H) and the methods used to process the data for bias and gravity levels.

  10. Respiratory gas exchange using a triaxial alveolar gas diagram.

    PubMed Central

    Fuster, J. F.; Pages, T.; Palacios, L.

    1993-01-01

    A triaxial alveolar gas diagram to depict fractional concentration of oxygen, carbon dioxide and nitrogen is described, in which the R = 1 line is always implicit. Although it is not claimed that this representation leads to new insights into respiratory physiology, a method of plotting on a triaxial coordinate system has been found to be well suited to many applications when a direct display of fractional nitrogen concentration is required. PMID:8303637

  11. A nonlinear criterion for triaxial strength of inherently anisotropic rocks

    NASA Astrophysics Data System (ADS)

    Singh, Mahendra; Samadhiya, N. K.; Kumar, Ajit; Kumar, Vivek; Singh, Bhawani

    2015-07-01

    Rocks encountered at many underground construction sites are laminated and exhibit direction-dependent strength behavior. It is also a well-established fact that the strength varies in a nonlinear manner with confining pressure. There is a need of strength criterion which could capture the nonlinearity as well as the anisotropy in the triaxial strength behavior of the rocks. It is essential that the criterion should be simple and must involve minimum testing to the extent possible. Further, the parameters of the criterion should have wide acceptability among the geotechnical fraternity. In the present study, a nonlinear strength criterion for transversely isotropic rocks is presented. Critical state concept Barton (Int J Rock Mech Mining Sci Geomech Abstr 13(9):255-279, 1976) has been used to define the curvature of the criterion. With a correctly defined curvature and starting from a reference point (UCS), it is possible to accurately assess the triaxial strength for given confining pressure. An experimental study conducted on triaxial strength behavior of three types of anisotropic rocks namely phyllite, slate and orthoquartzite has been discussed. A data base comprising more than 1140 triaxial tests conducted worldwide on anisotropic rocks has been compiled. Statistical evaluation of goodness of fit of the proposed criterion to the data base has been carried out. Further, the predictive capabilities of the proposed criterion have been evaluated by determining the error in estimation of triaxial strength if only few triaxial test data are available for determining the criterion parameters. The data base has also been back analyzed to assess the critical confining pressure for anisotropic rocks. Statistically, the critical confining pressure for anisotropic rocks can be taken nearly equal to 1.25 times the maximum UCS (obtained by applying load either parallel or perpendicular to planes of anisotropy). It is concluded that reasonable estimates of the triaxial

  12. Triaxial Burke-Schumann Flames with Applications to Flame Synthesis

    NASA Technical Reports Server (NTRS)

    Chao, B. H.; Axelbaum, R. L.; Gokoglu, Suleyman (Technical Monitor)

    2000-01-01

    The problem of a flame generated by three coaxial flows is solved by extending the Burke-Schumann methodology to include a third stream. The solution is particularly relevant to flame synthesis wherein multiple tubes are often employed either to introduce inert as a diffusion barrier or to introduce more than two reactants. The general problem is solved where the inner and outer tubes contain reactants and the middle tube contains either an inert or a third reactant. Relevant examples are considered and the results show that the triaxial Burke-Schumann flame can be substantially more complicated than the traditional Burke-Schumann flame. When the middle flow is inert the flame temperature is no longer constant but increases axially, reaching a maximum at the flame centerline. At the exit the flame does not sit on the tube exit but instead resides between the inner and outer tubes, resulting in an effective barrier for particle build-up on the burner rim. For the case of a third reactant in the middle flow, synthesis chemistry where the inner reaction is endothermic and the outer reaction is exothermic is considered. In addition to showing the flame temperature and flame shape, the results identify conditions wherein reaction is not possible due to insufficient heat transfer from the outer flame to support the inner flame reaction.

  13. Ambulatory respiratory rate detection using ECG and a triaxial accelerometer.

    PubMed

    Chan, Alexander M; Ferdosi, Nima; Narasimhan, Ravi

    2013-01-01

    Continuous monitoring of respiratory rate in ambulatory conditions has widespread applications for screening of respiratory diseases and remote patient monitoring. Unfortunately, minimally obtrusive techniques often suffer from low accuracy. In this paper, we describe an algorithm with low computational complexity for combining multiple respiratory measurements to estimate breathing rate from an unobtrusive chest patch sensor. Respiratory rates derived from the respiratory sinus arrhythmia (RSA) and modulation of the QRS amplitude of electrocardiography (ECG) are combined with a respiratory rate derived from tri-axial accelerometer data. The three respiration rates are combined by a weighted average using weights based on quality metrics for each signal. The algorithm was evaluated on 15 elderly subjects who performed spontaneous and metronome breathing as well as a variety of activities of daily living (ADLs). When compared to a reference device, the mean absolute error was 1.02 breaths per minute (BrPM) during metronome breathing, 1.67 BrPM during spontaneous breathing, and 2.03 BrPM during ADLs. PMID:24110623

  14. Triaxial Superdeformed Bands in ^163Tm

    NASA Astrophysics Data System (ADS)

    Pattabiraman, N. S.; Ghugre, S. S.; Garg, Umesh; Li, T.; Nayak, B. K.; Zhu, S.; Chakrawarthy, R. S.; Macchiavelli, A. O.; Janssens, R. V. F.

    2002-10-01

    Following the recent discovery of triaxial superdeformation bands in the Z = 71, 72 nuclei [1,2], we have investigated the Z = 69 nucleus ^163 Tm using the reaction ^130 Te( ^37 Cl, 4n) ^163 Tm with a beam energy of 170 MeV. Gamma-ray spectroscopy was performed using the Gammasphere array at LBNL. The data were sorted into a hypercube. The preliminary results have indicated two bands with δ E _γ 60 keV above the previously known 5286 keV, 49/2^- state. These bands appear to talk to one another. It may be recalled that evidence for wobbling motion has recently been reported in the isobaric nucleus ^163 Lu The detailed experimental results and comparisons with the neighboring nuclei will be presented. [1] H. Amro et al, Phys. Lett. B 506, 39(2001). [2] G. Schonwasser eet al., Eur. Phys. J. A13, 291(2002). [3] D. R. Jensen et al, Nucl. Phys. A 703, 3 (2002).

  15. Latitudinal Libration in a Triaxial Ellipsoid

    NASA Astrophysics Data System (ADS)

    Cebron, D.; Vantieghem, S.; Noir, J.

    2014-12-01

    As a consequence of gravitational coupling with their orbital partners, the rotational dynamics of planets and moons exhibits periodic variations in time, such as precession, libration and nutation. Moreover, most planets are subject to tidal forces, which in combination with the planet's rotation, result in a departure from a purely spherically symmetric object. In this theoretical-numerical study, we investigate the flows driven by latitudinal libration (i.e. an oscillation of the figure axis with respect to the mean rotation axis) within liquid cores of triaxial ellipsoidal shape. We first derive a uniform-vorticity solution for the equations of motion, and find that it can resonate with the spin-over inertial mode. Using a reduced model of viscosity (J. Noir and D. Cébron, J. Fluid Mech., vol. 737 (2013)), we deduce that the amplitude of the flow at resonance diverges as the inverse square-root of the Ekman number. Our results are consistent with previous studies in a spheroidal geometry (K. Zhang et al., J. Fluid Mech., vol. 696 (2012)). In a following step, we address the dynamical stability of this uniform-vorticity flow. We show that it is prone to inertial instabilities arising from a parametric resonance between two free inertial modes and the base flow. We also show that the vigor of the instability is governed by the frequency and two parameters that capture the dependence on the libration amplitude and geometry. The resonant nature of these phenomena suggests that libration in latitude, despite its small amplitude, may drive strong flows within planetary cores with possibly major implications for heat transport, dissipation and magnetic field generation/induction. This is discussed at planetary settings for the cores of the Moon, Io and Mercury, and the ancient lunar core.

  16. Triaxial fiber optic magnetic field sensor for MRI applications

    NASA Astrophysics Data System (ADS)

    Filograno, Massimo L.; Pisco, Marco; Catalano, Angelo; Forte, Ernesto; Aiello, Marco; Soricelli, Andrea; Davino, Daniele; Visone, Ciro; Cutolo, Antonello; Cusano, Andrea

    2016-05-01

    In this paper, we report a fiber-optic triaxial magnetic field sensor, based on Fiber Bragg Gratings (FBGs) integrated with giant magnetostrictive material, the Terfenol-D. The realized sensor has been designed and engineered for Magnetic Resonance Imaging (MRI) applications. A full magneto-optical characterization of the triaxial sensing probe has been carried out, providing the complex relationship among the FBGs wavelength shift and the applied magnetostatic field vector. Finally, the developed fiber optic sensors have been arranged in a sensor network composed of 20 triaxial sensors for mapping the magnetic field distribution in a MRI-room at a diagnostic center in Naples (SDN), equipped with Positron emission tomography/magnetic resonance (PET/MR) instrumentation. Experimental results reveal that the proposed sensor network can be efficiently used in MRI centers for performing quality assurance tests, paving the way for novel integrated tools to measure the magnetic dose accumulated day by day by MRI operators.

  17. Volume-controlled hydrologic property measurements in triaxial systems

    USGS Publications Warehouse

    Olsen, Harold W.; Willden, Arthur T.; Kiusalaas, Nicholas J.; Nelson, Karl R.; Poeter, Eileen P.

    1994-01-01

    New capabilities for hydrologic property measurements in triaxial systems include: (1) volume-controlled and simultaneous measurements of hydraulic conductivity and one-dimensional consolidation (or specific storage) of a saturated test specimen; and (2) volume-controlled measurements of hydraulic conductivity, matric potential, and the variation of these properties with the moisture content of an unsaturated test specimen. Data on saturated kaolinite demonstrate simultaneous hydraulic-conductivity and one-dimensional consolidation tests with continuous monitoring of both vertical and horizontal effective stresses. Data on well-graded silty sand demonstrate the feasibility of concurrent constant-flow hydraulic conductivity and mattic potential measurements, and the variation of these properties with moisture content, for undisturbed and unsaturated specimens mounted in triaxial cells. Refinements needed to realize the full potential of these capabilities include a more rigid triaxial cell to minimize compliance, and an improved technique for measuring hydraulic-head differences within an unsaturated test specimen.

  18. Quasiequilibrium models for triaxially deformed rotating compact stars

    NASA Astrophysics Data System (ADS)

    Huang, Xing; Markakis, Charalampos; Sugiyama, Noriyuki; Uryū, Kōji

    2008-12-01

    Quasiequilibrium models of rapidly rotating triaxially deformed stars are computed in general relativistic gravity, assuming a conformally flat spatial geometry (Isenberg-Wilson-Mathews formulation) and a polytropic equation of state. Highly deformed solutions are calculated on the initial slice covered by spherical coordinate grids, centered at the source, in all angular directions up to a large truncation radius. Constant rest mass sequences are calculated from nearly axisymmetric to maximally deformed triaxial configurations. Selected parameters are to model (proto-) neutron stars; the compactness is M/R=0.001, 0.1, 0.14, and 0.2 for polytropic index n=0.3 and M/R=0.001, 0.1, 0.12, and 0.14 for n=0.5, where M/R refers to that of a nonrotating spherical star having the same rest mass. We confirmed that the triaxial solutions exist for these parameters as in the case of Newtonian polytropes. However, it is also found that the triaxial sequences become shorter for higher compactness, and those disappear at a certain large compactness for the n=0.5 case. In the scenario of the contraction of proto-neutron stars being subject to strong viscosity and rapid cooling, it is plausible that, once the viscosity driven secular instability sets in during the contraction, the proto-neutron stars are always maximally deformed triaxial configurations, as long as the compactness and the equation of state parameters allow such triaxial sequences. Detection of gravitational waves from such sources may be used as another probe for the nuclear equation of state.

  19. LOW GRADIENT PERMEABILITY MEASUREMENTS IN A TRIAXIAL SYSTEM.

    USGS Publications Warehouse

    Olsen, H.W.; Nichols, R.W.; Rice, T.L.

    1985-01-01

    Permeability measurements were conducted with the flow-pump method on sand, sandy silt and silty clay specimens in a conventional triaxial system by introducing and withdrawing water at known constant flow rates into the base of a specimen with a flow-pump, and by monitoring the head difference induced across the length of the specimen with a sensitive differential pressure transducer. The results show that the previously reported advantages of the flow-pump method, compared with conventional constant head and falling head methods, were realized for permeability measurements in conventional triaxial equipment.

  20. Triaxiality of the ground states in the 174W

    NASA Astrophysics Data System (ADS)

    Ya, Tu; Chen, Y. S.; Liu, L.; Gao, Z. C.

    2016-05-01

    We have performed calculations for the ground states in 174W by using the projected total energy surface (PTES) calculations. Both the ground state (g.s.) band and its γ band reproduce the experimental data. Further discussion about the triaxiality in 174W has been made by transition quardrupole moment (Qt) and comparing between the PTES and TRS methods.

  1. Estimating Energy Expenditure with the RT3 Triaxial Accelerometer

    ERIC Educational Resources Information Center

    Maddison, Ralph; Jiang, Yannan; Vander Hoorn, Stephen; Mhurchu, Cliona Ni; Lawes, Carlene M. M.; Rodgers, Anthony; Rush, Elaine

    2009-01-01

    The RT3 is a relatively new triaxial accelerometer that has replaced the TriTrac. The aim of this study was to validate the RT3 against doubly labeled water (DLW) in a free-living, mixed weight sample of adults. Total energy expenditure (TEE) was measured over a 15-day period using DLW. Activity-related energy expenditure (AEE) was estimated by…

  2. A Fiber Bragg Grating Sensing Based Triaxial Vibration Sensor

    PubMed Central

    Li, Tianliang; Tan, Yuegang; Liu, Yi; Qu, Yongzhi; Liu, Mingyao; Zhou, Zude

    2015-01-01

    A fiber Bragg grating (FBG) sensing based triaxial vibration sensor has been presented in this paper. The optical fiber is directly employed as elastomer, and the triaxial vibration of a measured body can be obtained by two pairs of FBGs. A model of a triaxial vibration sensor as well as decoupling principles of triaxial vibration and experimental analyses are proposed. Experimental results show that: sensitivities of 86.9 pm/g, 971.8 pm/g and 154.7 pm/g for each orthogonal sensitive direction with linearity are separately 3.64%, 1.50% and 3.01%. The flat frequency ranges reside in 20–200 Hz, 3–20 Hz and 4–50 Hz, respectively; in addition, the resonant frequencies are separately 700 Hz, 40 Hz and 110 Hz in the x/y/z direction. When the sensor is excited in a single direction vibration, the outputs of sensor in the other two directions are consistent with the outputs in the non-working state. Therefore, it is effectively demonstrated that it can be used for three-dimensional vibration measurement. PMID:26393616

  3. Method of using triaxial magnetic fields for making particle structures

    DOEpatents

    Martin, James E.; Anderson, Robert A.; Williamson, Rodney L.

    2005-01-18

    A method of producing three-dimensional particle structures with enhanced magnetic susceptibility in three dimensions by applying a triaxial energetic field to a magnetic particle suspension and subsequently stabilizing said particle structure. Combinations of direct current and alternating current fields in three dimensions produce particle gel structures, honeycomb structures, and foam-like structures.

  4. Simulation of triaxial response of granular materials by modified DEM

    NASA Astrophysics Data System (ADS)

    Wang, XiaoLiang; Li, JiaChun

    2014-12-01

    A modified discrete element method (DEM) with rolling effect taken into consideration is developed to examine macroscopic behavior of granular materials in this study. Dimensional analysis is firstly performed to establish the relationship between macroscopic mechanical behavior, mesoscale contact parameters at particle level and external loading rate. It is found that only four dimensionless parameters may govern the macroscopic mechanical behavior in bulk. The numerical triaxial apparatus was used to study their influence on the mechanical behavior of granular materials. The parametric study indicates that Poisson's ratio only varies with stiffness ratio, while Young's modulus is proportional to contact modulus and grows with stiffness ratio, both of which agree with the micromechanical model. The peak friction angle is dependent on both inter-particle friction angle and rolling resistance. The dilatancy angle relies on inter-particle friction angle if rolling stiffness coefficient is sufficiently large. Finally, we have recommended a calibration procedure for cohesionless soil, which was at once applied to the simulation of Chende sand using a series of triaxial compression tests. The responses of DEM model are shown in quantitative agreement with experiments. In addition, stress-strain response of triaxial extension was also obtained by numerical triaxial extension tests.

  5. Regularities of acoustic emission in coal samples under triaxial compression

    SciTech Connect

    Shkuratnik, V.L.; Filimonov, Y.L.; Kuchurin, S.V.

    2005-02-01

    The results are cited for the experimental study of acoustoemission processes in anthracite samples under triaxial compression by the Karman scheme at the constant rate of axial strain. From a comparison of the stress-strain and acoustoemission curves, the features of acoustic emission parameters in various deformation stages are revealed and the physicomechanical properties of coal are estimated.

  6. A Fiber Bragg Grating Sensing Based Triaxial Vibration Sensor.

    PubMed

    Li, Tianliang; Tan, Yuegang; Liu, Yi; Qu, Yongzhi; Liu, Mingyao; Zhou, Zude

    2015-01-01

    A fiber Bragg grating (FBG) sensing based triaxial vibration sensor has been presented in this paper. The optical fiber is directly employed as elastomer, and the triaxial vibration of a measured body can be obtained by two pairs of FBGs. A model of a triaxial vibration sensor as well as decoupling principles of triaxial vibration and experimental analyses are proposed. Experimental results show that: sensitivities of 86.9 pm/g, 971.8 pm/g and 154.7 pm/g for each orthogonal sensitive direction with linearity are separately 3.64%, 1.50% and 3.01%. The flat frequency ranges reside in 20-200 Hz, 3-20 Hz and 4-50 Hz, respectively; in addition, the resonant frequencies are separately 700 Hz, 40 Hz and 110 Hz in the x/y/z direction. When the sensor is excited in a single direction vibration, the outputs of sensor in the other two directions are consistent with the outputs in the non-working state. Therefore, it is effectively demonstrated that it can be used for three-dimensional vibration measurement. PMID:26393616

  7. How UV photolysis accelerates the biodegradation and mineralization of sulfadiazine (SD).

    PubMed

    Pan, Shihui; Yan, Ning; Liu, Xinyue; Wang, Wenbing; Zhang, Yongming; Liu, Rui; Rittmann, Bruce E

    2014-11-01

    Sulfadiazine (SD), one of broad-spectrum antibiotics, exhibits limited biodegradation in wastewater treatment due to its chemical structure, which requires initial mono-oxygenation reactions to initiate its biodegradation. Intimately coupling UV photolysis with biodegradation, realized with the internal loop photobiodegradation reactor, accelerated SD biodegradation and mineralization by 35 and 71 %, respectively. The main organic products from photolysis were 2-aminopyrimidine (2-AP), p-aminobenzenesulfonic acid (ABS), and aniline (An), and an SD-photolysis pathway could be identified using C, N, and S balances. Adding An or ABS (but not 2-AP) into the SD solution during biodegradation experiments (no UV photolysis) gave SD removal and mineralization rates similar to intimately coupled photolysis and biodegradation. An SD biodegradation pathway, based on a diverse set of the experimental results, explains how the mineralization of ABS and An (but not 2-AP) provided internal electron carriers that accelerated the initial mono-oxygenation reactions of SD biodegradation. Thus, multiple lines of evidence support that the mechanism by which intimately coupled photolysis and biodegradation accelerated SD removal and mineralization was through producing co-substrates whose oxidation produced electron equivalents that stimulated the initial mono-oxygenation reactions for SD biodegradation. PMID:25199943

  8. The SD oscillator and its attractors

    NASA Astrophysics Data System (ADS)

    Cao, Q.; Wiercigroch, M.; Pavlovskaia, E.; Grebogi, C.; Michael, J.; Thompson, T.

    2008-02-01

    We propose a new archetypal oscillator for smooth and discontinuous systems (SD oscillator). This oscillator behaves both smooth and discontinuous system depending on the value of the smoothness parameter. New dynamic behaviour is presented for the transitions from the smooth to discontinuous regime.

  9. Triaxial Swirl Injector Element for Liquid-Fueled Engines

    NASA Technical Reports Server (NTRS)

    Muss, Jeff

    2010-01-01

    A triaxial injector is a single bi-propellant injection element located at the center of the injector body. The injector element consists of three nested, hydraulic swirl injectors. A small portion of the total fuel is injected through the central hydraulic injector, all of the oxidizer is injected through the middle concentric hydraulic swirl injector, and the balance of the fuel is injected through an outer concentric injection system. The configuration has been shown to provide good flame stabilization and the desired fuel-rich wall boundary condition. The injector design is well suited for preburner applications. Preburner injectors operate at extreme oxygen-to-fuel mass ratios, either very rich or very lean. The goal of a preburner is to create a uniform drive gas for the turbomachinery, while carefully controlling the temperature so as not to stress or damage turbine blades. The triaxial injector concept permits the lean propellant to be sandwiched between two layers of the rich propellant, while the hydraulic atomization characteristics of the swirl injectors promote interpropellant mixing and, ultimately, good combustion efficiency. This innovation is suited to a wide range of liquid oxidizer and liquid fuels, including hydrogen, methane, and kerosene. Prototype testing with the triaxial swirl injector demonstrated excellent injector and combustion chamber thermal compatibility and good combustion performance, both at levels far superior to a pintle injector. Initial testing with the prototype injector demonstrated over 96-percent combustion efficiency. The design showed excellent high -frequency combustion stability characteristics with oxygen and kerosene propellants. Unlike the more conventional pintle injector, there is not a large bluff body that must be cooled. The absence of a protruding center body enhances the thermal durability of the triaxial swirl injector. The hydraulic atomization characteristics of the innovation allow the design to be

  10. Development of Data Acquisition System for Consolidated Undrained Triaxial Test

    NASA Astrophysics Data System (ADS)

    Lee, L. M.; Yasuo, T.; Wei, L. C.; Yuan, L. C.

    2016-07-01

    Consolidated Undrained (CU) triaxial test is a common laboratory test used in practice for determining effective and total shear strength parameters of soil. This paper reported works carried out to develop a data acquisition system for a self-assembled triaxial machine. The developed system was capable of acquiring signals from the installed sensors (i.e. pressure transducer, load cell, LVDT), interpreting and presenting the data in real-time graphs. In addition, the study highlighted the advantages of performing double vacuuming method to saturate the soil specimen. The saturation can be obtained quicker and at a significantly lower cell pressure compared to the conventional stepwise increment of back pressure and cell pressure method.

  11. Triaxial strongly deformed bands in {sup 160,161}Tm

    SciTech Connect

    Teal, C.; Lagergren, K.; Aguilar, A.; Riley, M. A.; Hartley, D. J.; Simpson, J.; Joss, D. T.; Carpenter, M. P.; Janssens, R. V. F.; Lauritsen, T.; Lister, C. J.; Zhu, S.; Garg, U.; Kondev, F. G.; Wang, X.; Ragnarsson, I.

    2008-07-15

    High-spin states in {sup 160,161}Tm were populated using the {sup 128}Te({sup 37}Cl, 5n and 4n) reactions at a beam energy of 170 MeV. Emitted {gamma} rays were detected in the Gammasphere spectrometer. Two rotational bands with high moments of inertia were discovered, one assigned to {sup 160}Tm, while the other tentatively assigned to {sup 161}Tm. These sequences display features similar to bands observed in neighboring Er, Tm, Yb, and Lu nuclei which have been discussed in terms of triaxial strongly deformed structures. Cranked Nilsson Strutinsky calculations have been performed that predict well-deformed triaxial shapes at high spin in {sup 160,161}Tm.

  12. Cartesian to geodetic coordinates conversion on a triaxial ellipsoid

    NASA Astrophysics Data System (ADS)

    Ligas, Marcin

    2012-04-01

    A new method of transforming Cartesian to geodetic (or planetographic) coordinates on a triaxial ellipsoid is presented. The method is based on simple reasoning coming from essentials of vector calculus. The reasoning results in solving a nonlinear system of equations for coordinates of the point being the projection of a point located outside or inside a triaxial ellipsoid along the normal to the ellipsoid. The presented method has been compared to a vector method of Feltens (J Geod 83:129-137, 2009) who claims that no other methods are available in the literature. Generally, our method turns out to be more accurate, faster and applicable to celestial bodies characterized by different geometric parameters. The presented method also fits to the classical problem of converting Cartesian to geodetic coordinates on the ellipsoid of revolution.

  13. Design and fabrication of a highly symmetrical capacitive triaxial accelerometer

    NASA Astrophysics Data System (ADS)

    Li, Gang; Li, Zhihong; Wang, Congshun; Hao, Yilong; Li, Ting; Zhang, Dacheng; Wu, Guoying

    2001-01-01

    A monolithic capacitive triaxial accelerometer using a highly symmetric quad-beam structure with a single seismic mass is developed. The structure of the accelerometer is analysed in detail theoretically and numerically. Static and modal simulations with a finite element method simulator are done to analyse the mechanical response at accelerations of different directions. The simulated results show that the accelerometer can sense triaxial acceleration separately and synchronously. It has sensitivities of about 7.66, 6.08 and 6.08 fF g-1 in the z-axis, x-axis and y-axis, respectively, and has nearly zero cross-axis sensitivity theoretically. Moreover, some design optimizations are made to improve its performance. Finally, the fabrication and the basic performance of the device are presented.

  14. Failure in laboratory fault models in triaxial tests

    USGS Publications Warehouse

    Savage, J.C.; Lockner, D.A.; Byerlee, J.D.

    1996-01-01

    A model of a fault in the Earth is a sand-filled saw cut in a granite cylinder subjected to a triaxial test. The saw cut is inclined at an angle a to the cylinder axis, and the sand filling is intended to represent gouge. The triaxial test subjects the granite cylinder to a constant confining pressure and increasing axial stress to maintain a constant rate of shortening of the cylinder. The required axial stress increases at a decreasing rate to a maximum, beyond which a roughly constant axial stress is sufficient to maintain the constant rate of shortening: Such triaxial tests were run for saw cuts inclined at angles ?? of 20??, 25??, 30??, 35??, 40??, 45??, and 50?? to the cylinder axis, and the apparent coefficient of friction ??a (ratio of the shear stress to the normal stress, both stresses resolved onto the saw cut) at failure was determined. Subject to the assumption that the observed failure involves slip on Coulomb shears (orientation unspecified), the orientation of the principal compression axis within the gouge can be calculated as a function of ??a for a given value of the coefficient of internal friction ??i. The rotation of the principal stress axes within the gouge in a triaxial test can then be followed as the shear strain across the gouge layer increases. For ??i ??? 0.8, an appropriate value for highly sheared sand, the observed values ??a imply that the principal-axis of compression within the gouge rotates so as to approach being parallel to the cylinder axis for all saw cut angles (20?? < ?? < 50??). In the limiting state (principal compression axis parallel to cylinder axis) the stress state in the gouge layer would be the same as that in the granite cylinder, and the failure criterion would be independent of the saw cut angle.

  15. Space acceleration measurement system triaxial sensor head error budget

    NASA Astrophysics Data System (ADS)

    Thomas, John E.; Peters, Rex B.; Finley, Brian D.

    1992-01-01

    The objective of the Space Acceleration Measurement System (SAMS) is to measure and record the microgravity environment for a given experiment aboard the Space Shuttle. To accomplish this, SAMS uses remote triaxial sensor heads (TSH) that can be mounted directly on or near an experiment. The errors of the TSH are reduced by calibrating it before and after each flight. The associated error budget for the calibration procedure is discussed here.

  16. Evaluation of the physical activity of anesthesiologists in the operating room during daily work using a triaxial accelerometer.

    PubMed

    Tanaka, Hidenori; Kawamata, Tomoyuki; Gen-No, Hirokazu; Nose, Hiroshi; Kawamata, Mikito

    2015-01-01

    Appropriate daily exercise is recommended to remain healthy for adults, including medical professionals. In this study, the authors quantified daily physical activity of anesthesiologists in the operating room using a newly developed triaxial accelerometer, Jukudai Mate. During daily work, mean±SD energy expenditure of staff was 576±181 kcal and was significantly higher than that of residents (400±95 kcal; p=007). The mean intensities of hourly physical activity of the staff and residents were estimated to be approximately 1.9 and 1.7 metabolic equivalents (METs), respectively. None of the anesthesiologists had more than 3 METs in intensity of physical activity. We concluded that the physical activity of anesthesiologists during daily work can be classified as light intensity. To promote and maintain health, anesthesiologists need physical activity of moderate or vigorous intensity off the job. PMID:24965320

  17. MAPPING THE ASYMMETRIC THICK DISK. I. A SEARCH FOR TRIAXIALITY

    SciTech Connect

    Larsen, Jeffrey A.; Haviland, Aaron P.; Cabanela, Juan E.; Humphreys, Roberta M. E-mail: cabanela@mnstate.edu

    2010-02-15

    A significant asymmetry in the distribution of faint blue stars in the inner Galaxy, Quadrant 1 (l = 20 deg. - 45 deg.) compared to Quadrant 4 was first reported by Larsen and Humphreys in 1996. Parker et al. greatly expanded the survey to determine its spatial extent and shape and the kinematics of the affected stars. This excess in the star counts was subsequently confirmed by Juric et al. using Sloan Digital Sky Survey data. Possible explanations for the asymmetry include a merger remnant, a triaxial thick disk, and a possible interaction with the bar in the disk. In this paper, we describe our program of wide field photometry to map the asymmetry to fainter magnitudes and therefore larger distances. To search for the signature of triaxiality, we extended our survey to higher Galactic longitudes. We find no evidence for an excess of faint blue stars at l {>=}55 deg. including the faintest magnitude interval. The asymmetry and star count excess in Quadrant 1 is thus not due to a triaxial thick disk.

  18. Mechanical Properties of Triaxial Braided Carbon/Epoxy Composites

    NASA Technical Reports Server (NTRS)

    Bowman, C. L.; Roberts, G. D.; Braley, M. S.; Xie, M.; Booker, M. J.

    2003-01-01

    In an on-going effort to increase the safety and efficiency of turbine engines, the National Aeronautics and Space Administration is exploring lightweight alternatives to the metal containment structures that currently encase commercial jet engines. Epoxy reinforced with braided carbon fibers is a candidate structural material which may be suitable for an engine case. This paper reports flat-coupon mechanical-property experiments performed to compliment previously reported subcomponent impact testing and analytical simulation of containment structures. Triaxial-braid T700/5208 epoxy and triaxial-braid T700h436 toughened epoxy composites were evaluated. Also, two triaxial-braid architectures (0 degrees plus or minus 60 degrees, and 0 degrees plus or minus 45 degrees) with the M36 resin were evaluated through tension, compression, and shear testing. Tensile behavior was compared between standard straight-sided specimens (ASTM D3039) and bow-tie specimens. Both double-notch shear (ASTM D3846) and Iosepescu (ASTM D5379) tests were performed as well. The M36/O degrees plus or minus 45 degrees configuration yield the best response when measurements were made parallel to the axial tows. Conversely, the M36/0 degrees plus or minus 60 degrees configuration was best when measurements were made perpendicular to the axial tows. The results were used to identify critical properties and to augment the analysis of impact experiments.

  19. Mechanical Properties of Triaxial Braided Carbon/Epoxy Composites

    NASA Technical Reports Server (NTRS)

    Bowman, C. L.; Roberts, G. D.; Braley, M. S.; Xie, M.; Booker, M. J.

    2003-01-01

    In an on-going effort to increase the safety and efficiency of turbine engines, the National Aeronautics and Space Administration is exploring lightweight alternatives to the metal containment structures that currently encase commercial jet engines. Epoxy reinforced with braided carbon fibers is a candidate structural material which may be suitable for an engine case. This paper reports flat-coupon mechanical-property experiments performed to compliment previously reported subcomponent impact testing and analytical simulation of containment structures. Triaxial-braid T700/5208 epoxy and triaxial-braid T700/M36 toughened epoxy composites were evaluated. Also, two triaxial-braid architectures (0 +/- 60 deg., 0 +/- 45 deg.) with the M36 resin were evaluated through tension, compression, and shear testing. Tensile behavior was compared between standard straight-sided specimens (ASTM D3039) and bowtie specimens. Both double-notch shear (ASTM D3846) and Iosepescu (ASTM D5379) tests were performed as well. The M36/0 +/- 45 deg. configuration yield the best response when measurements were made parallel to the axial tows. Conversely, the M36/0 +/- 60 deg. configuration was best when measurements were made perpendicular to the axial tows. The results were used to identify critical properties and to augment the analysis of impact experiments.

  20. Chemical analyses of pore water from boreholes USW SD-6 and USW WT-24, Yucca Mountain, Nevada.

    PubMed

    Yang, In C; Peterman, Zell E; Scofield, Kevin M

    2003-01-01

    Analyses of pore water extracted from cores of boreholes USW SD-6 in the central part and USW WT-24 in the northern part of Yucca Mountain, Nevada, show significant vertical and lateral variations in dissolved-ion concentrations. Analyses of samples of only a few milliliters of pore water extracted by uniaxial or triaxial compression and by ultracentrifugation methods from adjacent core samples are generally in agreement, within the analytical error of 10% to 15%. However, the values of silica for water obtained by ultracentrifugation are consistently lower than values for water obtained by compression. The larger concentrations probably are due to localized pressure solution of silicate minerals during compression. The shallower water from core in borehole USW SD-6 was extracted from nonwelded units collectively referred to as the Paintbrush Tuff nonwelded (PTn). The deeper water was from core in both boreholes USW SD-6 and USW WT-24 in the nonwelded units referred to as the Calico Hills nonwelded (CHn). Significant differences in mean dissolved-ion concentrations in pore water between the PTn and CHn are (1) decreases in Ca, Mg, SO(4), and NO(3) and (2) increases in HCO(3) and (Na+K)/(Ca+Mg) ratios. The decrease in NO(3) and the increase in HCO(3) could be the result of denitrification through the oxidation of organic matter. The decrease in Ca and associated increase in (Na+K)/(Ca+Mg) is the result of ion exchange with zeolites in the CHn in borehole USW WT-24. This effect is not nearly as pronounced in borehole USW SD-6, probably reflecting a smaller amount of zeolitization of the CHn in USW SD-6. Geochemical calculations using the PHREEQC code indicate that the pore water from both boreholes USW SD-6 and USW WT-24 is uniformly undersaturated in anhydrite, gypsum, and amorphous silica, but supersaturated in quartz and chalcedony. The saturation of calcite, aragonite, sepiolite, and dolomite is more variable from sample to sample. PMID:12714300

  1. Experimental study of upper sd shell nuclei and evolution of sd-fp shell gap

    SciTech Connect

    Sarkar, M. Saha

    2012-06-27

    The intruder orbitals from the fp shell play important role in the structure of nuclei around the line of stability in the upper sd shell. Experimentally we have studied {sup 35}Cl, {sup 30}P, {sup 36}Cl, {sup 37}Ar and {sup 34}Cl in this mass region using the INGA setup. Large basis cross-shell shell model calculations have indicated the need for change of the sd-fp energy gap for reliable reproduction of negative parity and high spin positive parity states. Indication of population of states of large deformation has been found in our data. Theoretical interpretation of these states has been discussed.

  2. Search for multiple chiral doublets in rhodium isotopes

    SciTech Connect

    Peng, J.; Sagawa, H.; Zhang, S. Q.; Yao, J. M.; Zhang, Y.; Meng, J.

    2008-02-15

    The deformation in rhodium isotopes is investigated using adiabatic and configuration-fixed constrained triaxial relativistic mean field (RMF) approaches. The triaxial deformations are found in the ground states of {sup 102,104,106,108,110}Rh, which is consistent with triaxial Skyrme Hartree-Fock calculations. Several minima with triaxial deformation in {sup 104,106,108,110}Rh are obtained by the configuration-fixed constrained calculations. The corresponding configurations are characterized by the quantum numbers |nljm> obtained by transforming wave functions from a Cartesian basis to a spherical basis. The possible existence of multiple chiral doublets (M{chi}D) is demonstrated in {sup 104,106,108,110}Rh isotopes, based on different particle-hole configurations and triaxial deformations.

  3. Temperature as a predictive tool for plantar triaxial loading.

    PubMed

    Yavuz, Metin; Brem, Ryan W; Davis, Brian L; Patel, Jalpa; Osbourne, Abe; Matassini, Megan R; Wood, David A; Nwokolo, Irene O

    2014-11-28

    Diabetic foot ulcers are caused by moderate repetitive plantar stresses in the presence of peripheral neuropathy. In severe cases, the development of these foot ulcers can lead to lower extremity amputations. Plantar pressure measurements have been considered a capable predictor of ulceration sites in the past, but some investigations have pointed out inconsistencies when solely relying on this method. The other component of ground reaction forces/stresses, shear, has been understudied due to a lack of adequate equipment. Recent articles reported the potential clinical significance of shear in diabetic ulcer etiology. With the lack of adequate tools, plantar temperature has been used as an alternative method for determining plantar triaxial loading and/or shear. However, this method has not been previously validated. The purpose of this study was to analyze the potential association between exercise-induced plantar temperature increase and plantar stresses. Thirteen healthy individuals walked on a treadmill for 10 minutes at 3.2km/h. Pre and post-exercise temperature profiles were obtained with a thermal camera. Plantar triaxial stresses were quantified with a custom-built stress plate. A statistically significant correlation was observed between peak shear stress (PSS) and temperature increase (r=0.78), but not between peak resultant stress (PRS) and temperature increase (r=0.46). Plantar temperature increase could predict the location of PSS and PRS in 23% and 39% of the subjects, respectively. Only a moderate linear relationship was established between triaxial plantar stresses and walking-induced temperature increase. Future research will investigate the value of nonlinear models in predicting plantar loading through foot temperature. PMID:25446272

  4. Understanding nuclei in the upper sd - shell

    SciTech Connect

    Sarkar, M. Saha; Bisoi, Abhijit; Ray, Sudatta; Kshetri, Ritesh; Sarkar, S.

    2014-08-14

    Nuclei in the upper-sd shell usually exhibit characteristics of spherical single particle excitations. In the recent years, employment of sophisticated techniques of gamma spectroscopy has led to observation of high spin states of several nuclei near A ≃ 40. In a few of them multiparticle, multihole rotational states coexist with states of single particle nature. We have studied a few nuclei in this mass region experimentally, using various campaigns of the Indian National Gamma Array setup. We have compared and combined our empirical observations with the large-scale shell model results to interpret the structure of these nuclei. Indication of population of states of large deformation has been found in our data. This gives us an opportunity to investigate the interplay of single particle and collective degrees of freedom in this mass region.

  5. The effect of galaxy triaxiality on globular clusters

    NASA Technical Reports Server (NTRS)

    Ostriker, J. P.; Binney, J.; Saha, P.

    1989-01-01

    Evidence of triaxiality and central mass concentration in the Galaxy and in M31 and M87 is examined. It is proposed that globular clusters on box orbits in the inner parts of these systems pass close enough to the center to be destroyed by tidal shocks. Remaining clusters will preferentially populate tube orbits with relatively high angular momentum. The process is used to explain the cluster distribution in M87 reported by Lauer and Kormendy (1986). Models are presented for cluster destruction by massive black holes in M87's dark halo. Consideration is given to techniques for testing the suggestion that clusters form only on box orbits.

  6. Shape coexistence and triaxiality in nuclei near 80Zr

    NASA Astrophysics Data System (ADS)

    Zheng, S. J.; Xu, F. R.; Shen, S. F.; Liu, H. L.; Wyss, R.; Yan, Y. P.

    2014-12-01

    Total-Routhian-surface calculations have been performed to investigate the shape evolutions of A ˜80 nuclei: Zr-8480,Sr-8076 , and Mo,8684 . Shape coexistences of spherical, prolate, and oblate deformations have been found in these nuclei. Particularly for the nuclei 80Sr and 82Zr , the energy differences between two shape-coexisting states are less than 220 keV. At high spins, the g9 /2 shell plays an important role in shape evolutions. It has been found that the alignment of the g9 /2 quasiparticles drives nuclei to be triaxial.

  7. Parametric design of tri-axial nested Helmholtz coils

    SciTech Connect

    Abbott, Jake J.

    2015-05-15

    This paper provides an optimal parametric design for tri-axial nested Helmholtz coils, which are used to generate a uniform magnetic field with controllable magnitude and direction. Circular and square coils, both with square cross section, are considered. Practical considerations such as wire selection, wire-wrapping efficiency, wire bending radius, choice of power supply, and inductance and time response are included. Using the equations provided, a designer can quickly create an optimal set of custom coils to generate a specified field magnitude in the uniform-field region while maintaining specified accessibility to the central workspace. An example case study is included.

  8. TRIAXIAL AND SHEAR TESTING OF SELECTED BACKFILL MATERIALS

    SciTech Connect

    N. E. Kramer

    2000-08-07

    The Subsurface Performance Testing Section is performing tests in the Department of Energy's Atlas Facility to evaluate the performance of various backfill materials. Triaxial and shear tests were conducted on select backfill materials. The specific materials tested were: crushed tuff, overton sand, 4- 10 silica sand, 1/4'' dolostone/marble, and limestone. The objective of this report is to provide an estimated value for Poisson's ratio, determine internal friction angle, and stress-strain modulus of the backfill materials that were tested. These basic parameters are necessary for the selection of a backfill material to be included in the repository. This report transmits the results in both hardcopy and electronic formats plus describes the methodology and interpretation of the results. No conclusions will be drawn about the test results, as this will be the purview of other reports. The scope of this report is to use the triaxial and shear testing information and calculate, the internal friction angle, stress-strain modulus, and provide an estimate of Poisson's ratio (Sowers 1979, p. 199) of the selected backfill materials. Standard laboratory procedures, mentioned in Section 2 of this report, were used.

  9. Principal Components Analysis of Triaxial Vibration Data From Helicopter Transmissions

    NASA Technical Reports Server (NTRS)

    Tumer, Irem Y.; Huff, Edward M.

    2001-01-01

    Research on the nature of the vibration data collected from helicopter transmissions during flight experiments has led to several crucial observations believed to be responsible for the high rates of false alarms and missed detections in aircraft vibration monitoring systems. This work focuses on one such finding, namely, the need to consider additional sources of information about system vibrations. In this light, helicopter transmission vibration data, collected using triaxial accelerometers, were explored in three different directions, analyzed for content, and then combined using Principal Components Analysis (PCA) to analyze changes in directionality. In this paper, the PCA transformation is applied to 176 test conditions/data sets collected from an OH58C helicopter to derive the overall experiment-wide covariance matrix and its principal eigenvectors. The experiment-wide eigenvectors. are then projected onto the individual test conditions to evaluate changes and similarities in their directionality based on the various experimental factors. The paper will present the foundations of the proposed approach, addressing the question of whether experiment-wide eigenvectors accurately model the vibration modes in individual test conditions. The results will further determine the value of using directionality and triaxial accelerometers for vibration monitoring and anomaly detection.

  10. Models of cuspy triaxial stellar systems - IV. Rotating systems

    NASA Astrophysics Data System (ADS)

    Carpintero, D. D.; Muzzio, J. C.

    2016-06-01

    We built two self-consistent models of triaxial, cuspy, rotating stellar systems adding rotation to non-rotating models presented in previous papers of this series. The final angular velocity of the material is not constant and varies with the distance to the centre and with the height over the equator of the systems, but the figure rotation is very uniform in both cases. Even though the addition of rotation to the models modifies their original semi-axes ratios, the final rotating models are considerably flattened and triaxial. An analysis of the orbital content of the models shows that about two-thirds of their orbits are chaotic yet the models are very stable over intervals of the order of one Hubble time. The bulk of regular orbits are short-axis tubes, while long-axis tubes are replaced by tubes whose axes lie on the short-long axes plane, but do not coincide with the major axis. Other types of regular orbits that do not appear in non-rotating systems, like horseshoes and orbits that cross themselves, are also found in the present models. Finally, our frequency maps show empty regions where studies of orbits on fixed potentials found orbits, a likely consequence of the self-consistency of our models that excludes them.

  11. Characterization of Damage in Triaxial Braid Composites Under Tensile Loading

    NASA Technical Reports Server (NTRS)

    Littell, Justin D.; Binienda, Wieslaw K.; Roberts, Gary D.; Goldberg, Robert K.

    2009-01-01

    Carbon fiber composites utilizing flattened, large tow yarns in woven or braided forms are being used in many aerospace applications. Their complex fiber architecture and large unit cell size present challenges in both understanding deformation processes and measuring reliable material properties. This report examines composites made using flattened 12k and 24k standard modulus carbon fiber yarns in a 0 /+60 /-60 triaxial braid architecture. Standard straight-sided tensile coupons are tested with the 0 axial braid fibers either parallel with or perpendicular to the applied tensile load (axial or transverse tensile test, respectively). Nonuniform surface strain resulting from the triaxial braid architecture is examined using photogrammetry. Local regions of high strain concentration are examined to identify where failure initiates and to determine the local strain at the time of initiation. Splitting within fiber bundles is the first failure mode observed at low to intermediate strains. For axial tensile tests splitting is primarily in the 60 bias fibers, which were oriented 60 to the applied load. At higher strains, out-of-plane deformation associated with localized delamination between fiber bundles or damage within fiber bundles is observed. For transverse tensile tests, the splitting is primarily in the 0 axial fibers, which were oriented transverse to the applied load. The initiation and accumulation of local damage causes the global transverse stress-strain curves to become nonlinear and causes failure to occur at a reduced ultimate strain. Extensive delamination at the specimen edges is also observed.

  12. Retrograde closed orbits in a rotating triaxial potential

    NASA Astrophysics Data System (ADS)

    Heisler, J.; Merritt, D.; Schwarzschild, M.

    1982-07-01

    Four closed periodic orbit sequences are determined numerically, and their stability is investigated by the standard Floquet method, for the case of a specific, triaxial rotating potential. The sequences comprise (1) stable anomalous orbits that are tipped to the long axis which they circle, so that they also circle the short rotation axis, (2) unstable, anomalous orbits circling the intermediate axis, otherwise behaving like (1), (3) stable, normal retrograde orbits lying in the equatorial plane, which become unstable against perpendicular perturbations in Binney's instability strip, and (4) Z-axis orbits lying on the rotation axis, which, although stable in their inner section, become unstable to perturbations parallel to the intermediate axis farther out, and to the long axis farther out still. The entire set contains one composite sequence which is stable over the entire energy range, consisting of the outer section of the normal retrograde orbits, the sequence of the anomalous orbits, and the inner section of the Z-axis orbits. It is suggested that the composite sequence may be relevant to the dynamics of gas masses captured by rotating triaxial galaxies.

  13. Characterization of Triaxial Braided Composite Material Properties for Impact Simulation

    NASA Technical Reports Server (NTRS)

    Roberts, Gary D.; Goldberg, Robert K.; Biniendak, Wieslaw K.; Arnold, William A.; Littell, Justin D.; Kohlman, Lee W.

    2009-01-01

    The reliability of impact simulations for aircraft components made with triaxial braided carbon fiber composites is currently limited by inadequate material property data and lack of validated material models for analysis. Improvements to standard quasi-static test methods are needed to account for the large unit cell size and localized damage within the unit cell. The deformation and damage of a triaxial braided composite material was examined using standard quasi-static in-plane tension, compression, and shear tests. Some modifications to standard test specimen geometries are suggested, and methods for measuring the local strain at the onset of failure within the braid unit cell are presented. Deformation and damage at higher strain rates is examined using ballistic impact tests on 61- by 61- by 3.2-mm (24- by 24- by 0.125-in.) composite panels. Digital image correlation techniques were used to examine full-field deformation and damage during both quasi-static and impact tests. An impact analysis method is presented that utilizes both local and global deformation and failure information from the quasi-static tests as input for impact simulations. Improvements that are needed in test and analysis methods for better predictive capability are examined.

  14. Stellar spiral structures in triaxial dark matter haloes

    NASA Astrophysics Data System (ADS)

    Hu, Shaoran; Sijacki, Debora

    2016-09-01

    We employ very high resolution simulations of isolated Milky Way-like galaxies to study the effect of triaxial dark matter haloes on exponential stellar discs. Non-adiabatic halo shape changes can trigger two-armed grand-design spiral structures which extend all the way to the edge of the disc. Their pattern speed coincides with the inner Lindblad resonance indicating that they are kinematic density waves which can persist up to several Gyr. In dynamically cold discs, grand-design spirals are swing amplified and after a few Gyr can lead to the formation of (multi-armed) transient recurrent spirals. Stellar discs misaligned to the principal planes of the host triaxial halo develop characteristic integral shaped warps, but otherwise exhibit very similar spiral structures as aligned discs. For the grand-design spirals in our simulations, their strength dependence with radius is determined by the torque on the disc, suggesting that by studying grand-design spirals without bars it may be possible to set constraints on the tidal field and host dark matter halo shape.

  15. Triaxiality and exotic rotations at high spins in 134Ce

    NASA Astrophysics Data System (ADS)

    Petrache, C. M.; Guo, S.; Ayangeakaa, A. D.; Garg, U.; Matta, J. T.; Nayak, B. K.; Patel, D.; Carpenter, M. P.; Chiara, C. J.; Janssens, R. V. F.; Kondev, F. G.; Lauritsen, T.; Seweryniak, D.; Zhu, S.; Ghugre, S. S.; Palit, R.

    2016-06-01

    High-spin states in 134Ce have been investigated using the 116Cd(22Ne,4 n ) reaction and the Gammasphere array. The level scheme has been extended to an excitation energy of ˜30 MeV and spin ˜54 ℏ . Two new dipole bands and four new sequences of quadrupole transitions were identified. Several new transitions have been added to a number of known bands. One of the strongly populated dipole bands was revised and placed differently in the level scheme, resolving a discrepancy between experiment and model calculations reported previously. Configurations are assigned to the observed bands based on cranked Nilsson-Strutinsky calculations. A coherent understanding of the various excitations, both at low and high spins, is thus obtained, supporting an interpretation in terms of coexistence of stable triaxial, highly deformed, and superdeformed shapes up to very high spins. Rotations around different axes of the triaxial nucleus, and sudden changes of the rotation axis in specific configurations, are identified, further elucidating the nature of high-spin collective excitations in the A =130 mass region.

  16. Mechanical properties of triaxially braided composites: Experimental and analytical results

    NASA Technical Reports Server (NTRS)

    Masters, John E.; Foye, Raymond L.; Pastore, Christopher M.; Gowayed, Yasser A.

    1992-01-01

    The unnotched tensile properties of 2-D triaxial braid reinforced composites from both an experimental and an analytical viewpoint are studied. The materials are graphite fibers in an epoxy matrix. Three different reinforcing fiber architectures were considered. Specimens were cut from resin transfer molded (RTM) composite panels made from each braid. There were considerable differences in the observed elastic constants from different size strain gage and extensometer reading. Larger strain gages gave more consistent results and correlated better with the extensometer reading. Experimental strains correlated reasonably well with analytical predictions in the longitudinal, 0 degrees, fiber direction but not in the transverse direction. Tensile strength results were not always predictable even in reinforcing directions. Minor changes in braid geometry led to disproportionate strength variations. The unit cell structure of the triaxial braid was discussed with the assistance of computer analysis of the microgeometry. Photomicrographs of braid geometry were used to improve upon the computer graphics representations of unit cells. These unit cells were used to predict the elastic moduli with various degrees of sophistication. The simple and the complex analyses were generally in agreement but none adequately matched the experimental results for all the braids.

  17. Mechanical properties of triaxially braided composites: Experimental and analytical results

    NASA Technical Reports Server (NTRS)

    Masters, John E.; Foye, Raymond L.; Pastore, Christopher M.; Gowayed, Yasser A.

    1992-01-01

    This paper investigates the unnotched tensile properties of two-dimensional triaxial braid reinforced composites from both an experimental and analytical viewpoint. The materials are graphite fibers in an epoxy matrix. Three different reinforcing fiber architectures were considered. Specimens were cut from resin transfer molded (RTM) composite panels made from each braid. There were considerable differences in the observed elastic constants from different size strain gage and extensometer readings. Larger strain gages gave more consistent results and correlated better with the extensometer readings. Experimental strains correlated reasonably well with analytical predictions in the longitudinal, zero degree, fiber direction but not in the transverse direction. Tensile strength results were not always predictable even in reinforcing directions. Minor changes in braid geometry led to disproportionate strength variations. The unit cell structure of the triaxial braid was discussed with the assistence of computer analysis of the microgeometry. Photomicrographs of the braid geometry were used to improve upon the computer graphics representations of unit cells. These unit cells were used to predict the elastic moduli with various degrees of sophistication. The simple and the complex analyses were generally in agreement but none adequately matched the experimental results for all the braids.

  18. Single particle calculations for a Woods-Saxon potential with triaxial deformations, and large Cartesian oscillator basis (TRIAXIAL 2014, Third version of the code Triaxial)

    NASA Astrophysics Data System (ADS)

    Mohammed-Azizi, B.; Medjadi, D. E.

    2014-11-01

    Theory and FORTRAN program of the first version of this code (TRIAXIAL) have already been described in detail in Computer Physics Comm. 156 (2004) 241-282. A second version of this code (TRIAXIAL 2007) has been given in CPC 176 (2007) 634-635. The present FORTRAN program is the third version (TRIAXIAL 2014) of the same code. Now, It is written in free format. As the former versions, this FORTRAN program solves the same Schrodinger equation of the independent particle model of the atomic nucleus with the same method. However, the present version is much more convenient. In effect, it is characterized by the fact that the eigenvalues and the eigenfunctions can be given by specific subroutines. The latters did not exist in the old versions (2004 and 2007). In addition, it is to be noted that in the previous versions, the eigenfunctions were only given by their coefficients of their expansion onto the harmonic oscillator basis. This method is needed in some cases. But in other cases, it is preferable to treat the eigenfunctions directly in configuration space. For this reason, we have implemented an additional subroutine for this task. Some other practical subroutines have also been implemented. Moreover, eigenvalues and eigenfunctions are recorded onto several files. All these new features of the code and some important aspects of its structure are explained in the document ‘Triaxial2014 use.pdf’. Catalogue identifier: ADSK_v3_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADSK_v3_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 13672 No. of bytes in distributed program, including test data, etc.: 217598 Distribution format: tar.gz Programming language: FORTRAN 77/90 (double precision). Computer: PC. Pentium 4, 2600MHz and beyond. Operating system: WINDOWS XP

  19. Single particle calculations for a Woods-Saxon potential with triaxial deformations, and large Cartesian oscillator basis (TRIAXIAL 2014, Third version of the code Triaxial)

    NASA Astrophysics Data System (ADS)

    Mohammed-Azizi, B.; Medjadi, D. E.

    2014-11-01

    Theory and FORTRAN program of the first version of this code (TRIAXIAL) have already been described in detail in Computer Physics Comm. 156 (2004) 241-282. A second version of this code (TRIAXIAL 2007) has been given in CPC 176 (2007) 634-635. The present FORTRAN program is the third version (TRIAXIAL 2014) of the same code. Now, It is written in free format. As the former versions, this FORTRAN program solves the same Schrodinger equation of the independent particle model of the atomic nucleus with the same method. However, the present version is much more convenient. In effect, it is characterized by the fact that the eigenvalues and the eigenfunctions can be given by specific subroutines. The latters did not exist in the old versions (2004 and 2007). In addition, it is to be noted that in the previous versions, the eigenfunctions were only given by their coefficients of their expansion onto the harmonic oscillator basis. This method is needed in some cases. But in other cases, it is preferable to treat the eigenfunctions directly in configuration space. For this reason, we have implemented an additional subroutine for this task. Some other practical subroutines have also been implemented. Moreover, eigenvalues and eigenfunctions are recorded onto several files. All these new features of the code and some important aspects of its structure are explained in the document ‘Triaxial2014 use.pdf’. Catalogue identifier: ADSK_v3_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADSK_v3_0.html Program obtainable from: CPC Program Library, Queen’s University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 13672 No. of bytes in distributed program, including test data, etc.: 217598 Distribution format: tar.gz Programming language: FORTRAN 77/90 (double precision). Computer: PC. Pentium 4, 2600MHz and beyond. Operating system: WINDOWS XP

  20. Final report of the safety assessment of Alcohol Denat., including SD Alcohol 3-A, SD Alcohol 30, SD Alcohol 39, SD Alcohol 39-B, SD Alcohol 39-C, SD Alcohol 40, SD Alcohol 40-B, and SD Alcohol 40-C, and the denaturants, Quassin, Brucine Sulfate/Brucine, and Denatonium Benzoate.

    PubMed

    2008-01-01

    Alcohol Denat. is the generic term used by the cosmetics industry to describe denatured alcohol. Alcohol Denat. and various specially denatured (SD) alcohols are used as cosmetic ingredients in a wide variety of products. Many denaturants have been previously considered, on an individual basis, as cosmetic ingredients by the Cosmetic Ingredient Review (CIR) Expert Panel, whereas others, including Brucine and Brucine Sulfate, Denatonium Benzoate, and Quassin, have not previously been evaluated. Quassin is a bitter alkaloid obtained from the wood of Quassia amara. Quassin has been used as an insect antifeedant and insecticide and several studies demonstrate its effectiveness. At oral doses up to 1000 mg/kg using rats, Quassin was not toxic in acute and short-term tests, but some reversible piloerection, decrease in motor activity, and a partial loss of righting reflex were found in mice at 500 mg/kg. At 1000 mg/kg given intraperitoneally (i.p.), all mice died within 24 h of receiving treatment. In a cytotoxicity test with brine shrimp, 1 mg/ml of Quassin did not possess any cytotoxic or antiplasmodial activity. Quassin administered to rat Leydig cells in vitro at concentrations of 5-25 ng/ml inhibited both the basal and luteinizing hormone (LH)-stimulated testosterone secretion in a dose-related fashion. Quassin at doses up to 2.0 g/kg in drinking water using rats produced no significant effect on the body weights, but the mean weights of the testes, seminal vesicles, and epididymides were significantly reduced, and the weights of the anterior pituitary glands were significantly increased. The sperm counts and levels of LH, follicle-stimulating hormone (FSH), and testosterone were significantly lower in groups treated with Quassin. Brucine is a derivative of 2-hydroxystrychnine. Swiss-Webster mice given Brucine base, 30 ml/kg, had an acute oral LD(50) of 150 mg/kg, with central nervous system depression followed by convulsions and seizures in some cases. In those

  1. Design and characterization of a resonant triaxial microprobe

    NASA Astrophysics Data System (ADS)

    Goj, Boris; Dressler, Lothar; Hoffmann, Martin

    2015-12-01

    A new trend for tactile microprobes leads to oscillating microprobes in order to overcome the drawbacks resulting from high Hertzian stress and disturbing surface forces. Thin water films on the measurement surface result in the so-called sticking effect which causes measurement faults such as snap-back and false triggering. This leads to measurement errors and low measurement speeds. We present an innovative oscillating triaxial microprobe which safely avoids sticking in all Cartesian measurement directions. The system design as well as the characterization of the microprobe are presented in this work. The low number of coupling elements, the batch-capable design and the low contact forces are the key features of the microprobe.

  2. Internal stresses in Phobos and other triaxial bodies

    NASA Technical Reports Server (NTRS)

    Dobrovolskis, A. R.

    1982-01-01

    The unusual dynamical behavior of Phobos, its strange appearance, and its mysterious network of grooves all make it an intriguing object. Geophysical studies, though, have been hampered by the lack of suitable theories applicable to nonspherical bodies. In this paper the Martian satellites are modeled as homogeneous, elastic triaxial ellipsoids subject to tidal, rotational, and self-gravitational stresses. A novel semianalytical treatment then gives the stress and strain fields throughout their interiors. Yield phenomena and their possible surface expressions are also investigated. The results indicate that Phobos and Deimos have always been stable with respect to tidal fracture or disruption, but that Phobos will probably break up before colliding with Mars. Applications of the new formulation to other nonspherical bodies in the solar system are also discussed.

  3. Triaxial thermopile array geo-heat-flow sensor

    DOEpatents

    Carrigan, Charles R.; Hardee, Harry C.; Reynolds, Gerald D.; Steinfort, Terry D.

    1992-01-01

    A triaxial thermopile array geothermal heat flow sensor is designed to measure heat flow in three dimensions in a reconstituted or unperturbed subsurface regime. Heat flow can be measured in conductive or permeable convective media. The sensor may be encased in protective pvc tubing and includes a plurality of thermistors and an array of heat flow transducers arranged in a vertical string. The transducers produce voltage proportional to heat flux along the subsurface regime and permit direct measurement of heat flow in the subsurface regime. The presence of the thermistor array permits a comparison to be made between the heat flow estimates obtained from the transducers and heat flow calculated using temperature differences and Fourier's Law. The device is extremely sensitive with an accuracy of less than 0.1 Heat Flow Units (HFU) and may be used for long term readings.

  4. Orbital decay in aspherical galaxies. II - Triaxial systems

    SciTech Connect

    Statler, T. S. Joint Institute for Laboratory Astrophysics, Boulder, CO )

    1991-07-01

    A previous analysis of orbital decay of small satellite galaxies into moderately oblate, axisymmetrical cannibal galaxies with Staeckel potentials is generalized here to triaxial systems with arbitary anisotropy and internal streaming. The orbital evolution to be expected in systems with differing degrees of anisotropy or rotation is briefly discussed. The evolution of some representative orbits is presented in detail using the orbit-averaged anisotropic Chandrasekhar drag and the distribution functions for perfect ellipsoids. The validity of orbit averaging is assessed by comparing the results with ensembles of single-particle orbits integrated directly in the same potential and the same drag prescription. An attempt is made to gauge the validity of the Chandrasekhar formula by comparison with restricted N-body solutions. It is found that the orbit-averaged evolution is consistent with such simulations. 40 refs.

  5. Orbital decay in aspherical galaxies. II - Triaxial systems

    NASA Technical Reports Server (NTRS)

    Statler, Thomas S.

    1991-01-01

    A previous analysis of orbital decay of small satellite galaxies into moderately oblate, axisymmetrical cannibal galaxies with Staeckel potentials is generalized here to triaxial systems with arbitary anisotropy and internal streaming. The orbital evolution to be expected in systems with differing degrees of anisotropy or rotation is briefly discussed. The evolution of some representative orbits is presented in detail using the orbit-averaged anisotropic Chandrasekhar drag and the distribution functions for perfect ellipsoids. The validity of orbit averaging is assessed by comparing the results with ensembles of single-particle orbits integrated directly in the same potential and the same drag prescription. An attempt is made to gauge the validity of the Chandrasekhar formula by comparison with restricted N-body solutions. It is found that the orbit-averaged evolution is consistent with such simulations.

  6. True Tri-axial testing of Castlegate Sandstone

    NASA Astrophysics Data System (ADS)

    Ingraham, M. D.; Issen, K.; Holcomb, D.

    2009-12-01

    Deformation bands in high porosity sandstone are an important geological feature for geologists and petroleum engineers; however, their formation is not fully understood. Axisymmetric compression, the common test for this material, is not sufficient to fully evaluate localization criteria. This study seeks to investigate the influence of the second principal stress on the failure and the formation of deformation bands in Castlegate sandstone. Experimental results from tests run in the axisymmetric compression stress state, as well as a stress state between axisymmetric compression and pure shear will be presented. Samples are tested using a custom triaxial testing rig at Sandia National Laboratories capable of applying stresses up to 400 MPa. Acoustic emissions are used to locate deformation bands should they not be visible on the specimen exterior. It is suspected that the second invariant of stress has a strong contribution to the failure mode and band formation. These results could have significant bearing on petroleum extraction as well as carbon dioxide sequestration.

  7. Shape coexistence and triaxiality in the superheavy nuclei.

    PubMed

    Cwiok, S; Heenen, P-H; Nazarewicz, W

    2005-02-17

    Superheavy nuclei represent the limit of nuclear mass and charge; they inhabit the remote corner of the nuclear landscape, whose extent is unknown. The discovery of new elements with atomic numbers Z > or = 110 has brought much excitement to the atomic and nuclear physics communities. The existence of such heavy nuclei hangs on a subtle balance between the attractive nuclear force and the disruptive Coulomb repulsion between protons that favours fission. Here we model the interplay between these forces using self-consistent energy density functional theory; our approach accounts for spontaneous breaking of spherical symmetry through the nuclear Jahn-Teller effect. We predict that the long-lived superheavy elements can exist in a variety of shapes, including spherical, axial and triaxial configurations. In some cases, we anticipate the existence of metastable states and shape isomers that can affect decay properties and hence nuclear half-lives. PMID:15716943

  8. Triaxial thermopile array geo-heat-flow sensor

    DOEpatents

    Carrigan, C.R.; Hardee, H.C.; Reynolds, G.D.; Steinfort, T.D.

    1990-01-01

    A triaxial thermopile array geothermal heat flow sensor is designed to measure heat flow in three dimensions in a reconstituted or unperturbed subsurface regime. Heat flow can be measured in conductive or permeable convective media. The sensor may be encased in protective pvc tubing and includes a plurality of thermistors and an array of heat flow transducers produce voltage proportional to heat flux along the subsurface regime and permit direct measurement of heat flow in the subsurface regime. The presence of the thermistor array permits a comparison to be made between the heat flow estimates obtained from the transducers and heat flow calculated using temperature differences and Fourier's Law. The device is extremely sensitive with an accuracy of less than 0.1 Heat Flow Units (HFU) and may be used for long term readings. 6 figs.

  9. Strain limit dependence on stress triaxiality for pressure vessel steel

    NASA Astrophysics Data System (ADS)

    Deng, Y.-C.; Chen, G.; Yang, X.-F.; Xu, T.

    2009-08-01

    In this paper, the failure characteristics of pressure vessel materials were investigated, and measurement and analysis approaches for ductile fracture strains were studied. Based on uniaxial tensile tests of notched round bar specimens, combined with finite element analyses and microscopic observations of fracture surface, the relationships between the stress triaxiality factor and the ductile fracture strain are proposed for three typical Chinese pressure vessel steels, 16MnR, Q235 and 0Cr18Ni9. The comparison of experimental fracture strains with the multiaxial strain limit specified in ASME VIII-2 2007 shows that the strain limit criterion of ASME is suitable for carbon steels but not suitable for austenitic stainless steels for Chinese pressure vessel steels. To improve the calculation accuracy for fracture strain of materials and to develop the strain limit criterion for Chinese pressure vessel materials, more experimental studies and numerical analyses on fracture strain are necessary.

  10. Particle-triaxial rotor calculations around {sup 195}Pt

    SciTech Connect

    Petkov, P.; Brentano, P. von; Jolie, J.; Jolos, R. V.

    2009-01-28

    Particle-triaxial rotor calculations have been performed for the negative parity states in {sup 195}Pt and {sup 193}Os. The doublet structure of the low-lying excited states is better described when a Woods-Saxon potential is used compared to the use of a modified harmonic oscillator potential. The predicted level energies and B(E2) transition strengths are in overall agreement with the experimental data and the U(6/12) results. The ratios of B(E2) values between the states of two doublets agree well with those obtained assuming a pseudospin symmetry. In {sup 193}Os, the model calculations can be used for clarification of the spin assignments in cases where they are ambiguous. It is interesting to check them by new precise spin determination.

  11. Triaxial determination of shear strength of tire chips

    SciTech Connect

    Wu, W.Y.; Benda, C.C.; Cauley, R.F.

    1997-05-01

    Triaxial compression tests following stress paths of constant {sigma}{sub 1} were conducted to determine the shear strength of five processed scrap tire products having different gradations and particle shapes. The interparticle frictional component was separated from the total shear strength according to the energy correction concept proposed by researchers. The experimental results show that all five tire chip products have ultimate internal friction angles of 45{degree} to over 60{degree}. The interparticle frictional component of the strength was fully mobilized and nearly reached a constant value after approximately 5% axial strain. The experimental results confirmed that the strength parameter obtained with constant {sigma}{sub 1} was more reasonable. This finding is supported by field observation in which the tire chips have an angle of repose ranging from 37{degree} to 43{degree} (loosely stock piled) and up to 85{degree} (compacted). The engineering applications of the experimental results are discussed.

  12. Triaxial coreflood study of the hydraulic fracturing of Utica Shale

    NASA Astrophysics Data System (ADS)

    Carey, J. W.; Frash, L.; Viswanathan, H. S.

    2015-12-01

    One of the central questions in unconventional oil and gas production research is the cause of limited recovery of hydrocarbon. There are many hypotheses including: 1) inadequate penetration of fractures within the stimulated volume; 2) limited proppant delivery; 3) multiphase flow phenomena that blocks hydrocarbon migration; etc. Underlying any solution to this problem must be an understanding of the hydrologic properties of hydraulically fractured shale. In this study, we conduct triaxial coreflood experiments using a gasket sealing mechanism to characterize hydraulic fracture development and permeability of Utica Shale samples. Our approach also includes fracture propagation with proppants. The triaxial coreflood experiments were conducted with an integrated x-ray tomography system that allows direct observation of fracture development using x-ray video radiography and x-ray computed tomography at elevated pressure. A semi-circular, fracture initiation notch was cut into an end-face of the cylindrical samples (1"-diameter with lengths from 0.375 to 1"). The notch was aligned parallel with the x-ray beam to allow video radiography of fracture growth as a function of injection pressure. The proppants included tungsten powder that provided good x-ray contrast for tracing proppant delivery and distribution within the fracture system. Fractures were propagated at injection pressures in excess of the confining pressure and permeability measurements were made in samples where the fractures propagated through the length of the sample, ideally without penetrating the sample sides. Following fracture development, permeability was characterized as a function of hydrostatic pressure and injection pressure. X-ray video radioadiography was used to study changes in fracture aperture in relation to permeability and proppant embedment. X-ray tomography was collected at steady-state conditions to fully characterize fracture geometry and proppant distribution.

  13. Determination of critical stress triaxiality along yield locus of isotropic ductile materials under plane strain condition

    NASA Astrophysics Data System (ADS)

    Bhadauria, S. S.; Pathak, K. K.; Hora, M. S.

    2012-09-01

    It is widely accepted that failure due to plastic deformation in metals greatly depends on the stress triaxiality factor (TF). This article investigates the variation of stress triaxiality along the yield locus of ductile materials. Von Mises yield criteria and triaxiality factor have been used to determine the critical limits of stress triaxiality for the materials under plane strain condition. A generalized mathematical model for triaxiality factor has been formulated and a constrained optimization has been carried out using genetic algorithm. Finite element analysis of a two dimensional square plate has been carried out to verify the results obtained by the mathematical model. It is found that the set of values of the first and the second principal stresses on the yield locus, which results in maximum stress triaxiality, can be used to determine the location at which crack initiation may occur. Thus, the results indicate that while designing a certain component, such combination of stresses which leads the stress triaxiality to its critical value, should be avoided.

  14. Mechanical properties of gold twinned nanocubes under different triaxial tensile rates

    NASA Astrophysics Data System (ADS)

    Yang, Zailin; Zhang, Guowei; Luo, Gang; Sun, Xiaoqing; Zhao, Jianwei

    2016-08-01

    The gold twinned nanocubes under different triaxial tensile rates are explored by molecular dynamics simulation. Hydrostatic stress and Mises stress are defined in order to understand triaxial stresses. Twin boundaries prevent dislocations between twin boundaries from developing and dislocation angles are inconspicuous, which causes little difference between triaxial stresses. The mechanical properties of the nanocubes under low and high tensile rates are different. The curves of nanocubes under high tensile rates are more abrupt than those under low tensile rates. When the tensile rate is extremely big, the loadings are out of the nanocubes and there are not deformation and fracture in the internal nanocubes.

  15. Effects of triaxial deformation and pairing correlation on the proton emitter {sup 145}Tm

    SciTech Connect

    Yao, J. M.; Sun, B.; Woods, P. J.; Meng, J.

    2008-02-15

    The ground-state properties of the recent reported proton emitter {sup 145}Tm have been studied within the axially or triaxially deformed relativistic mean field (RMF) approaches, in which the pairing correlation is taken into account by the BCS-method with a constant pairing gap. It is found that triaxiality and pairing correlations play important roles in reproducing the experimental one proton separation energy. The single-particle level, the proton emission orbit, the deformation parameters {beta}=0.22 and {gamma}=28.98 deg. and the corresponding spectroscopic factor for {sup 145}Tm in the triaxial RMF calculation are given as well.

  16. Validation of uniaxial and triaxial accelerometers for the assessment of physical activity in preschool children

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Given the unique physical activity patterns of preschoolers, wearable electronic devices for quantitative assessment of physical activity require validation in this population. Study objective was to validate uniaxial and triaxial accelerometers in preschoolers. Room calorimetry was performed over 3...

  17. Shape trends and triaxiality in neutron-rich odd-mass Y and Nbisotopes

    SciTech Connect

    Luo, Y.X.; Rasmussen, J.O.; Gelberg, A.; Stefanescu, I.; Hamilton, J.H.; Ramayya, A.V.; Hwang, J.K.; Zhu, S.J.; Gore, P.M.; Fong,D.; Jones, E.F.; Wu, S.C.; Lee, I.Y.; Ginter, T.N.; Ma, W.C.; Ter-Akopian, G.M.; Daniel, A.V.; Stoyer, M.A.; Donangelo, R.

    2004-09-28

    New level schemes of Y and Nb isotopes are proposed based on measurements of prompt gamma rays from 252Cf fission at Gammasphere. Shape trends regarding triaxiality and quadrupole deformations are studied.

  18. Failure of Anisotropic Shale under Triaxial Stress Conditions

    NASA Astrophysics Data System (ADS)

    Zimmerman, R. W.; Ambrose, J.; Suarez-Rivera, R. F.

    2013-12-01

    Some rocks, such as shales, are highly anisotropic in their mechanical behavior. The value of the maximum principal stress that is needed to cause shear failure in a shale will depend not only on the values of the other two principal stresses, but also on the angle β between the maximum principal stress and the normal to the bedding plane. We have carried out triaxial compression tests on a suite of Mid-Bossier shale samples, at different confining stresses, and at a range of angles β. The data were fit with Jaeger's plane of weakness model, as well as with Pariseau's model for transversely isotropic rocks. After failure, the samples were examined with CT scans, and thin section images, to investigate the trajectory of the failure planes. According to the plane of weakness model, at values of β near 0° or 90°, failure will occur at a stress determined by the Coulomb failure criterion for the 'intact rock', and the failure plane will cut across the bedding planes. At intermediate angles, failure will occur at a stress determined by the strength parameters of the bedding plane, and the failure plane will be parallel to the bedding plane. (As there are two Coulomb strength parameters for the intact rock and for the bedding plane, the plane of weakness model contains four fitting parameters). The data were fit reasonably well with the plane of weakness model, except in the range of 15° < β < 35°. In this range, the rock was weaker than predicted by the model, and the failure 'plane' was much more irregular than would be predicted by a Coulomb-type model. Pariseau's model is an extension of the Drucker-Prager model that satisfies the symmetry requirements for a transversely isotropic material; it contains five arbitrary parameters. Unlike the plane of weakness model, this model predicts a smoothly continuous variation of strength with β. Pariseau's model was found to provide a slightly better fit to the data than did the plane of weakness model. Our current

  19. Signatures of bulge triaxiality from kinematics in Baade's window

    NASA Technical Reports Server (NTRS)

    Zhao, Hongsheng; Spergel, David N.; Rich, R. Michael

    1994-01-01

    We study a sample of 62 Baade's Window, (l,b) = (1, -4)deg, K giants that have published proper motions, radial velocity, and metallicity. Using R(sub 0) = 8 kpc, we construct the velocity ellipsoids, namely the 3x3 velocity dispersion tensors, for the metal rich stars ((Fe/H) greater than or equal to 0) and metal poor stars ((Fe/H) less than or equal to -0.2). After diagonalizing the tensor, we find a vertex deviation characteristic of a nonaxisymmetric system. Eigenvalues for the two velocity ellipsoids (sigma(sub 1), sigma(sub 2), sigma(sub 3)) are (126, 89, 65) +/- 13 km/s for the metal rich sample and (154, 77, 83) +/- 25 km/s for the metal poor sample with their long axes pointing to two nearly perpendicular directions (l(sub v), b(sub v)) = (-65 +/- 9 deg, +14 +/- 9 deg) and (l(sub v), b(sub v)) = (25 +/- 14 deg, -11 +/- 14 deg), respectively. The vertex deviations of the velocity ellipsoids cannot be consistently explained by any oblate model. We are able to reject the hypothesis that the metal poor and metal rich populations are drawn from the same distribution at better than the 97% confidence level. We populate orbits in a realistic bar potential with a Gaussian velocity distribution, allowing us to simulate and interpret observations. We conclude that the data are consistent with a triaxial bulge pointing towards (l,b) with l less than 0 deg and b = 0 deg as suggested by earlier work on gas dynamics and the observed light distribution. We also predict that low latitude (absolute value of b less than or equal to 4 deg) bulge fields should show the vertex deviation more strongly and would therefore be the best locations for future proper motion studies. In the classification scheme of Athanassoula et al. (1983) the metal rich stars appear to occupy the B-family orbits which rotate in the prograde sense in the rest frame and have boxy shapes that are aligned with and supporting the bar. The metal poor stars in the sample lag behind the metal rich bulge and

  20. Tensile strength of cementitious materials under triaxial loading

    NASA Astrophysics Data System (ADS)

    Tsubota, Shuji

    1998-11-01

    A general tension-compression-compression (sigmasb1, sigmasb2=sigmasb3) failure criterion for brittle materials is mathematically developed using FEM analysis and experimentally verified by use of the cementitious composite axial tensile test (CCATT). This tensile failure criterion is based on the stress concentration derived from the classical theory of elasticity. This analytical approach shows the upper bound of the tension-compression-compression failure surface for brittle materials. Since the CCATT applies confining hydraulic pressure, a tensile specimen is subjected to triaxial loading defined by the principal stress ratio sigmasb1/|sigmasb2|. When lateral pressure increases, tensile strength decreases; therefore, stress concentration is defined as a function of the principal stress ratio. The model has three distinct regions of behavior corresponding to the principal stress ratio, 0≤sigmasb1/|sigmasb2|<0.9 (high-lateral pressure), 0.9≤sigmasb1/|sigmasb2|<3.0 (medium-lateral pressure), 3.0≤sigmasb1/|sigmasb2| (low-lateral pressure). The experimental failure line shows true tensile strength of cementitious materials under low-lateral pressure. The predicted nominal stress fsb{ta} with large size specimens for the CCATT is written as$fsb{ta}=gamma*{1/{Kt}}*alpha* pwhere gamma$ is the size effect obtained by experimental results; Kt is the stress concentration factor derived from triaxial loading. Tensile strength values from the CCATT are compared to experimental results from other tests such as the uniaxial tensile test and the split cylinder test. CCATT results are analyzed using Weibull theory to measure material reliability and to develop characteristic stresses for construction design. Failure analysis using fractography was conducted on fractured cementitious materials and composites. The failure analysis on test specimens correlated well with FEM stress distributions and with the principal stress ratio. The observed fracture behavior (fracture

  1. Signatures of bulge triaxiality from kinematics in Baade's window

    NASA Astrophysics Data System (ADS)

    Zhao, Hongsheng; Spergel, David N.; Rich, R. Michael

    1994-12-01

    We study a sample of 62 Baade's Window, (l,b) = (1, -4)deg, K giants that have published proper motions, radial velocity, and metallicity. Using R0 = 8 kpc, we construct the velocity ellipsoids, namely the 3x3 velocity dispersion tensors, for the metal rich stars ((Fe/H) greater than or equal to 0) and metal poor stars ((Fe/H) less than or equal to -0.2). After diagonalizing the tensor, we find a vertex deviation characteristic of a nonaxisymmetric system. Eigenvalues for the two velocity ellipsoids (sigma1, sigma2, sigma3) are (126, 89, 65) +/- 13 km/s for the metal rich sample and (154, 77, 83) +/- 25 km/s for the metal poor sample with their long axes pointing to two nearly perpendicular directions (lv, bv) = (-65 +/- 9 deg, +14 +/- 9 deg) and (lv, bv) = (25 +/- 14 deg, -11 +/- 14 deg), respectively. The vertex deviations of the velocity ellipsoids cannot be consistently explained by any oblate model. We are able to reject the hypothesis that the metal poor and metal rich populations are drawn from the same distribution at better than the 97% confidence level. We populate orbits in a realistic bar potential with a Gaussian velocity distribution, allowing us to simulate and interpret observations. We conclude that the data are consistent with a triaxial bulge pointing towards (l,b) with l less than 0 deg and b = 0 deg as suggested by earlier work on gas dynamics and the observed light distribution. We also predict that low latitude (absolute value of b less than or equal to 4 deg) bulge fields should show the vertex deviation more strongly and would therefore be the best locations for future proper motion studies. In the classification scheme of Athanassoula et al. (1983) the metal rich stars appear to occupy the B-family orbits which rotate in the prograde sense in the rest frame and have boxy shapes that are aligned with and supporting the bar. The metal poor stars in the sample lag behind the metal rich bulge and appear to occupy R-family orbits which rotate

  2. Evaluation of uniaxial and triaxial shock isolation techniques for a piezoresistive accelerometer

    NASA Astrophysics Data System (ADS)

    Bateman, Vesta I.; Bell, R. Glenn, III; Brown, Fred A.; Davie, Neil T.; Nusser, Michael A.

    Development of both uniaxial and triaxial shock isolation techniques for pyroshock and impact tests has continued this year. The uniaxial shock isolation technique has demonstrated acceptable characteristics for a temperature range of -50 F to +186 F and a frequency bandwidth of DC to 10 kHz. The triaxial shock isolation technique has demonstrated acceptable results for a temperature range of -50 F to 70 F and a frequency bandwidth of DC to 10 kHz.

  3. CT discrimination and image process on damage process of unsaturated compacted loess during triaxial creep

    NASA Astrophysics Data System (ADS)

    Li, Xiaojun; Jiang, Lihua; Tang, Yichuan

    2010-08-01

    The triaxial creep compression tests of compacted loess samples are conducted with a new set of modified triaxial compression apparatus. With the new apparatus, the loess sample can be scanned with CT machine at the same time during compression process. The different damage process of compacted loess sample is directly observed for the first time with CT images and CT numbers. The initiation mechanisms of loess micro-crack during different creep compression processes are analyzed with CT images.

  4. User's Manual for Space Debris Surfaces (SD_SURF)

    NASA Technical Reports Server (NTRS)

    Elfer, N. C.

    1996-01-01

    A unique collection of computer codes, Space Debris Surfaces (SD_SURF), have been developed to assist in the design and analysis of space debris protection systems. SD_SURF calculates and summarizes a vehicle's vulnerability to space debris as a function of impact velocity and obliquity. An SD_SURF analysis will show which velocities and obliquities are the most probable to cause a penetration. This determination can help the analyst select a shield design which is best suited to the predominant penetration mechanism. The analysis also indicates the most suitable parameters for development or verification testing. The SD_SURF programs offer the option of either FORTRAN programs and Microsoft EXCEL spreadsheets and macros. The FORTRAN programs work with BUMPERII version 1.2a or 1.3 (Cosmic released). The EXCEL spreadsheets and macros can be used independently or with selected output from the SD_SURF FORTRAN programs.

  5. Chemical analyses of pore water from boreholes USW SD-6 and USW WT-24, Yucca Mountain, Nevada

    USGS Publications Warehouse

    Yang, I.C.; Peterman, Z.E.; Scofield, K.M.

    2003-01-01

    Analyses of pore water extracted from cores of boreholes USW SD-6 in the central part and USW WT-24 in the northern part of Yucca Mountain, Nevada, show significant vertical and lateral variations in dissolved-ion concentrations. Analyses of samples of only a few milliliters of pore water extracted by uniaxial or triaxial compression and by ultracentrifugation methods from adjacent core samples are generally in agreement, within the analytical error of 10% to 15%. However, the values of silica for water obtained by ultracentrifugation are consistently lower than values for water obtained by compression. The larger concentrations probably are due to localized pressure solution of silicate minerals during compression. The shallower water from core in borehole USW SD-6 was extracted from nonwelded units collectively referred to as the Paintbrush Tuff nonwelded (PTn). The deeper water was from core in both boreholes USW SD-6 and USW WT-24 in the nonwelded units referred to as the Calico Hills nonwelded (CHn). Significant differences in mean dissolved-ion concentrations in pore water between the PTn and CHn are (1) decreases in Ca, Mg, SO4, and NO3 and (2) increases in HCO3 and (Na+K)/(Ca+Mg) ratios. The decrease in NO3 and the increase in HCO3 could be the result of denitrification through the oxidation of organic matter. The decrease in Ca and associated increase in (Na+K)/(Ca+Mg) is the result of ion exchange with zeolites in the CHn in borehole USW WT-24. This effect is not nearly as pronounced in borehole USW SD-6, probably reflecting a smaller amount of zeolitization of the CHn in USW SD-6. Geochemical calculations using the PHREEQC code indicate that the pore water from both boreholes USW SD-6 and USW WT-24 is uniformly undersaturated in anhydrite, gypsum, and amorphous silica, but supersaturated in quartz and chalcedony. The saturation of calcite, aragonite, sepiolite, and dolomite is more variable from sample to sample. ?? 2002 Elsevier Science B.V. All rights

  6. A triaxial accelerometer monkey algorithm for optimal sensor placement in structural health monitoring

    NASA Astrophysics Data System (ADS)

    Jia, Jingqing; Feng, Shuo; Liu, Wei

    2015-06-01

    Optimal sensor placement (OSP) technique is a vital part of the field of structural health monitoring (SHM). Triaxial accelerometers have been widely used in the SHM of large-scale structures in recent years. Triaxial accelerometers must be placed in such a way that all of the important dynamic information is obtained. At the same time, the sensor configuration must be optimal, so that the test resources are conserved. The recommended practice is to select proper degrees of freedom (DOF) based upon several criteria and the triaxial accelerometers are placed at the nodes corresponding to these DOFs. This results in non-optimal placement of many accelerometers. A ‘triaxial accelerometer monkey algorithm’ (TAMA) is presented in this paper to solve OSP problems of triaxial accelerometers. The EFI3 measurement theory is modified and involved in the objective function to make it more adaptable in the OSP technique of triaxial accelerometers. A method of calculating the threshold value based on probability theory is proposed to improve the healthy rate of monkeys in a troop generation process. Meanwhile, the processes of harmony ladder climb and scanning watch jump are proposed and given in detail. Finally, Xinghai NO.1 Bridge in Dalian is implemented to demonstrate the effectiveness of TAMA. The final results obtained by TAMA are compared with those of the original monkey algorithm and EFI3 measurement, which show that TAMA can improve computational efficiency and get a better sensor configuration.

  7. Practical application of a tri-axial intensity array

    NASA Astrophysics Data System (ADS)

    Young, Victor W.; Hines, Paul C.; Hutt, Daniel L.; Humphrey, Victor F.

    2003-10-01

    Sound intensity is a vector quantity representing the magnitude and direction of propagating energy within an acoustic field. In an underwater environment, a single omni-directional hydrophone can be used to measure instantaneous acoustic pressure and a finite difference approximation applied to the pressure signals from a pair of such hydrophones can be used to calculate particle velocity in a single direction. Because the time average of the product of instantaneous pressure and particle velocity is intensity, a pair of hydrophones is all that is required to measure a single component of the intensity vector. The complete three-dimensional intensity vector can be calculated using three orthogonal pairs of hydrophones. To evaluate this concept a tri-axial array consisting of three orthogonal pairs of omni-directional hydrophones has been developed and tested on both calibrated sources at a laboratory facility and sources of opportunity during sea trails in littoral waters. The use of this array to calculate the intensity vector and thereby localize both near-field and far-field acoustic sources and characterize the directionality of ambient noise fields will be discussed. The impact of signal-to-noise ratio and the effect of self-noise will also be examined.

  8. Physical Activity in Hemodialysis Patients Measured by Triaxial Accelerometer

    PubMed Central

    Gomes, Edimar Pedrosa; Reboredo, Maycon Moura; Carvalho, Erich Vidal; Teixeira, Daniel Rodrigues; Carvalho, Laís Fernanda Caldi d'Ornellas; Filho, Gilberto Francisco Ferreira; de Oliveira, Julio César Abreu; Sanders-Pinheiro, Helady; Chebli, Júlio Maria Fonseca; de Paula, Rogério Baumgratz; Pinheiro, Bruno do Valle

    2015-01-01

    Different factors can contribute to a sedentary lifestyle among hemodialysis (HD) patients, including the period they spend on dialysis. The aim of this study was to evaluate characteristics of physical activities in daily life in this population by using an accurate triaxial accelerometer and to correlate these characteristics with physiological variables. Nineteen HD patients were evaluated using the DynaPort accelerometer and compared to nineteen control individuals, regarding the time spent in different activities and positions of daily life and the number of steps taken. HD patients were more sedentary than control individuals, spending less time walking or standing and spending more time lying down. The sedentary behavior was more pronounced on dialysis days. According to the number of steps taken per day, 47.4% of hemodialysis patients were classified as sedentary against 10.5% in control group. Hemoglobin level, lower extremity muscle strength, and physical functioning of SF-36 questionnaire correlated significantly with the walking time and active time. Looking accurately at the patterns of activity in daily life, HDs patients are more sedentary, especially on dialysis days. These patients should be motivated to enhance the physical activity. PMID:26090432

  9. SELF-SIMILAR SOLUTIONS OF TRIAXIAL DARK MATTER HALOS

    SciTech Connect

    Lithwick, Yoram; Dalal, Neal

    2011-06-20

    We investigate the collapse and the internal structure of dark matter halos. We consider halo formation from initially scale-free perturbations, for which gravitational collapse is self-similar. Fillmore and Goldreich and Bertschinger solved the one-dimensional (i.e., spherically symmetric) case. We generalize their results by formulating the three-dimensional self-similar equations. We solve the equations numerically and analyze the similarity solutions in detail, focusing on the internal density profiles of the collapsed halos. By decomposing the total density into subprofiles of particles that collapse coevally, we identify two effects as the main determinants of the internal density structure of halos: adiabatic contraction and the shape of a subprofile shortly after collapse; the latter largely reflects the triaxiality of the subprofile. We develop a simple model that describes the results of our three-dimensional simulations. In a companion paper, we apply this model to more realistic cosmological fluctuations, and thereby explain the origin of the nearly universal (NFW-like) density profiles found in N-body simulations.

  10. Identification of triaxial strongly deformed band in {sup 168}Hf.

    SciTech Connect

    Yadav, R. B.; Ma, W. C.; Hagemann, G. B.; Bengtsson, R.; Ryde, H.; Carpenter, M. P.; Janssens, R. V. F.; Khoo, T. L.; Kondev, F. G.; Lauritsen, T.; Lister, C. J.; Mississippi State Univ.; Niels Bohr Inst.; Lund Inst. of Tech.; Lund. Univ.; Univ. di Milano; Univ. of Bonn; U.S. Naval Academy; Univ. of Oslo; Univ. of Tennessee

    2008-01-01

    Possible decay pathways associated with three candidates for triaxial strongly deformed (TSD) bands in {sup 168}Hf have been investigated. The spin and excitation energy of the strongest band, TSD1, were determined approximately based on {gamma}-ray coincidence relationships. Discrete links were established for the second band. The overall agreement between the observed properties of the bands and cranking calculations using the ULTIMATE CRANKER code provides strong support for an interpretation where band TSD1 is associated with a TSD minimum, ({var_epsilon}{sub 2},{gamma}) {approx} (0.43,20{sup o}), involving the {pi}(i{sub 13/2}){sup 2} and the {nu}(j{sub 15/2}) high-j orbitals. This constitutes the first identification of a TSD band in Hf isotopes, which has been long-predicted by theoretical studies. The second band is understood as being associated with a near-prolate shape and a deformation enhanced with respect to the normal deformed bands. It is proposed to be built on the {pi}(i{sub 13/2}h{sub 9/2}) {nu}(i{sub 13/2}){sup 2} configuration.

  11. Physical Activity in Hemodialysis Patients Measured by Triaxial Accelerometer.

    PubMed

    Gomes, Edimar Pedrosa; Reboredo, Maycon Moura; Carvalho, Erich Vidal; Teixeira, Daniel Rodrigues; Carvalho, Laís Fernanda Caldi d'Ornellas; Filho, Gilberto Francisco Ferreira; de Oliveira, Julio César Abreu; Sanders-Pinheiro, Helady; Chebli, Júlio Maria Fonseca; de Paula, Rogério Baumgratz; Pinheiro, Bruno do Valle

    2015-01-01

    Different factors can contribute to a sedentary lifestyle among hemodialysis (HD) patients, including the period they spend on dialysis. The aim of this study was to evaluate characteristics of physical activities in daily life in this population by using an accurate triaxial accelerometer and to correlate these characteristics with physiological variables. Nineteen HD patients were evaluated using the DynaPort accelerometer and compared to nineteen control individuals, regarding the time spent in different activities and positions of daily life and the number of steps taken. HD patients were more sedentary than control individuals, spending less time walking or standing and spending more time lying down. The sedentary behavior was more pronounced on dialysis days. According to the number of steps taken per day, 47.4% of hemodialysis patients were classified as sedentary against 10.5% in control group. Hemoglobin level, lower extremity muscle strength, and physical functioning of SF-36 questionnaire correlated significantly with the walking time and active time. Looking accurately at the patterns of activity in daily life, HDs patients are more sedentary, especially on dialysis days. These patients should be motivated to enhance the physical activity. PMID:26090432

  12. Experimental and analytical characterization of triaxially braided textile composites

    NASA Technical Reports Server (NTRS)

    Masters, John E.; Fedro, Mark J.; Ifju, Peter G.

    1993-01-01

    There were two components, experimental and analytical, to this investigation of triaxially braided textile composite materials. The experimental portion of the study centered on measuring the materials' longitudinal and transverse tensile moduli, Poisson's ratio, and strengths. The identification of the damage mechanisms exhibited by these materials was also a prime objective of the experimental investigation. The analytical portion of the investigation utilized the Textile Composites Analysis (TECA) model to predict modulus and strength. The analytical and experimental results were compared to assess the effectiveness of the analysis. The figures contained in this paper reflect the presentation made at the conference. They may be divided into four sections: a definition of the material system tested; followed by a series of figures summarizing the experimental results (these figures contain results of a Moire interferometry study of the strain distribution in the material, examples and descriptions of the types of damage encountered in these materials, and a summary of the measured properties); a description of the TECA model follows the experimental results (this includes a series of predicted results and a comparison with measured values); and finally, a brief summary completes the paper.

  13. SD-MSAEs: Promoter recognition in human genome based on deep feature extraction.

    PubMed

    Xu, Wenxuan; Zhang, Li; Lu, Yaping

    2016-06-01

    The prediction and recognition of promoter in human genome play an important role in DNA sequence analysis. Entropy, in Shannon sense, of information theory is a multiple utility in bioinformatic details analysis. The relative entropy estimator methods based on statistical divergence (SD) are used to extract meaningful features to distinguish different regions of DNA sequences. In this paper, we choose context feature and use a set of methods of SD to select the most effective n-mers distinguishing promoter regions from other DNA regions in human genome. Extracted from the total possible combinations of n-mers, we can get four sparse distributions based on promoter and non-promoters training samples. The informative n-mers are selected by optimizing the differentiating extents of these distributions. Specially, we combine the advantage of statistical divergence and multiple sparse auto-encoders (MSAEs) in deep learning to extract deep feature for promoter recognition. And then we apply multiple SVMs and a decision model to construct a human promoter recognition method called SD-MSAEs. Framework is flexible that it can integrate new feature extraction or new classification models freely. Experimental results show that our method has high sensitivity and specificity. PMID:27018214

  14. Experimental investigation on mechanical damage characteristics of sandstone under triaxial cyclic loading

    NASA Astrophysics Data System (ADS)

    Yang, Sheng-Qi; Ranjith, P. G.; Huang, Yan-Hua; Yin, Peng-Fei; Jing, Hong-Wen; Gui, Yi-Lin; Yu, Qing-Lei

    2015-05-01

    The mechanical damage characteristics of sandstone subjected to cyclic loading is very significant to evaluate the stability and safety of deep excavation damage zones. However to date, there are very few triaxial experimental studies of sandstone under cyclic loading. Moreover, few X-ray micro-computed tomography (micro-CT) observations have been adopted to reveal the damage mechanism of sandstone under triaxial cyclic loading. Therefore, in this research, a series of triaxial cyclic loading tests and X-ray micro-CT observations were conducted to analyse the mechanical damage characteristics of sandstone with respect to different confining pressures. The results indicated that at lower confining pressures, the triaxial strength of sandstone specimens under cyclic loading is higher than that under monotonic loading; whereas at confining pressures above 20 MPa, the triaxial strength of sandstone under cyclic loading is approximately equal to that under monotonic loading. With the increase of cycle number, the crack damage threshold of sandstone first increases, and then significantly decreases and finally remains constant. Based on the damage evolution of irreversible deformation, it appears that the axial damage value of sandstone is all higher than the radial damage value before the peak strength; whereas the radial damage value is higher than the axial damage value after the peak strength. The evolution of Young's modulus and Poisson's ratio of sandstone can be characterized as having four stages: (i) Stage I: material strengthening; (ii) Stage II: material degradation; (iii) Stage III: material failure and (iv) Stage IV: structure slippage. X-ray micro-CT observations demonstrated that the CT scanning surface images of sandstone specimens are consistent with actual surface crack photographs. The analysis of the cross-sections of sandstone supports that the system of crack planes under triaxial cyclic loading is much more complicated than that under triaxial

  15. Theoretical study of triaxial shapes of neutron-rich Mo and Ru nuclei

    NASA Astrophysics Data System (ADS)

    Zhang, C. L.; Bhat, G. H.; Nazarewicz, W.; Sheikh, J. A.; Shi, Yue

    2015-09-01

    Background: Whether atomic nuclei can possess triaxial shapes at their ground states is still a subject of ongoing debate. According to theory, good prospects for low-spin triaxiality are in the neutron-rich Mo-Ru region. Recently, transition quadrupole moments in rotational bands of even-mass neutron-rich isotopes of molybdenum and ruthenium nuclei have been measured. The new data have provided a challenge for theoretical descriptions invoking stable triaxial deformations. Purpose: To understand experimental data on rotational bands in the neutron-rich Mo-Ru region, we carried out theoretical analysis of moments of inertia, shapes, and transition quadrupole moments of neutron-rich even-even nuclei around 110Ru using self-consistent mean-field and shell model techniques. Methods: To describe yrast structures in Mo and Ru isotopes, we use nuclear density functional theory (DFT) with the optimized energy density functional UNEDF0. We also apply triaxial projected shell model (TPSM) to describe yrast and positive-parity, near-yrast band structures. Results: Our self-consistent DFT calculations predict triaxial ground-state deformations in Mo,108106 and 108,110,112Ru and reproduce the observed low-frequency behavior of moments of inertia. As the rotational frequency increases, a negative-γ structure, associated with the aligned ν (h11/2) 2 pair, becomes energetically favored. The computed transition quadrupole moments vary with angular momentum, which reflects deformation changes with rotation; those variations are consistent with experiment. The TPSM calculations explain the observed band structures assuming stable triaxial shapes. Conclusions: The structure of neutron-rich even-even nuclei around 110Ru is consistent with triaxial shape deformations. Our DFT and TPSM frameworks provide a consistent and complementary description of experimental data.

  16. Behavior of an MBT waste in monotonic triaxial shear tests

    SciTech Connect

    Bhandari, Athma Ram Powrie, William

    2013-04-15

    Highlights: ► We studied the stress–strain–strength characteristics of an MBT waste. ► Rate of mobilization of strength with strain depends on initial density. ► Image analysis technique was used to determine whole-specimen displacement fields. ► Initial mode of deformation of a loose specimen is one-dimensional compression. ► Reinforcing elements enhance the resistance to lateral and volumetric deformation. - Abstract: Legislation in some parts of the world now requires municipal solid waste (MSW) to be processed prior to landfilling to reduce its biodegradability and hence its polluting potential through leachate and fugitive emission of greenhouse gases. This pre-processing may be achieved through what is generically termed mechanical–biological-treatment (MBT). One of the major concerns relating to MBT wastes is that the strength of the material may be less than for raw MSW, owing to the removal of sheet, stick and string-like reinforcing elements during processing. Also, the gradual increase in mobilized strength over strains of 30% or so commonly associated with unprocessed municipal solid waste may not occur with treated wastes. This paper describes a series of triaxial tests carried out to investigate the stress–strain–strength characteristics of an MBT waste, using a novel digital image analysis technique for the determination of detailed displacement fields over the whole specimen. New insights gained into the mechanical behavior of MBT waste include the effect of density on the stress–strain response, the initial 1-D compression of lightly consolidated specimens, and the likely reinforcing effect of small sheet like particles remaining in the waste.

  17. Tidal spin down rates of homogeneous triaxial viscoelastic bodies

    NASA Astrophysics Data System (ADS)

    Quillen, Alice C.; Kueter-Young, Andrea; Frouard, Julien; Ragozzine, Darin

    2016-08-01

    We use numerical simulations to measure the sensitivity of the tidal spin down rate of a homogeneous triaxial ellipsoid to its axis ratios by comparing the drift rate in orbital semi-major axis to that of a spherical body with the same mass, volume and simulated rheology. We use a mass-spring model approximating a viscoelastic body spinning around its shortest body axis, with spin aligned with orbital spin axis, and in circular orbit about a point mass. The torque or drift rate can be estimated from that predicted for a sphere with equivalent volume if multiplied by 0.5 (1 + b^4/a^4)(b/a)^{-4/3} (c/a)^{-α _c} where b/a and c/a are the body axis ratios and index αc ≈ 1.05 is consistent with the random lattice mass spring model simulations but αc = 4/3 suggested by scaling estimates. A homogeneous body with axis ratios 0.5 and and 0.8, like Haumea, has orbital semi-major axis drift rate about twice as fast as a spherical body with the same mass, volume and material properties. A simulation approximating a mostly rocky body but with 20% of its mass as ice concentrated at its ends has a drift rate 10 times faster than the equivalent homogeneous rocky sphere. However, this increase in drift rate is not enough to allow Haumea's satellite, Hi'iaka, to have tidally drifted away from Haumea to its current orbital semi-major axis.

  18. Star Streams in Triaxial Isochrone Potentials with Sub-halos

    NASA Astrophysics Data System (ADS)

    Carlberg, R. G.

    2015-07-01

    The velocity, position, and action variable evolutions of a tidal stream drawn out of a star cluster in a triaxial isochrone potential, containing a sub-halo population, reproduces many of the orbital effects of more general cosmological halos but allows for the easy calculation of orbital actions. We employ a spherical shell code, which we show accurately reproduces the results of a tree gravity code for a collisionless star cluster. Streams from clusters on high eccentricity orbits, e≳ 0.6, can spread out so much that the amount of material at high enough surface density to stand out on the sky may be only a few percent of the stream’s total mass. Low eccentricity streams remain more spatially coherent, but sub-halos both broaden the stream and displace the centerline with details depending on the orbits allowed within the potential. Overall, the majority of stream particles have changes in their total actions of only 1%-2%, leaving the mean stream relatively undisturbed. A halo with 1% of the mass in sub-halos typically spreads the velocity distribution about a factor of two wider than would be expected for a smooth halo. Strong density variations, “gaps,” along with mean velocity offsets, are clearly detected in low eccentricity streams for even a 0.2% sub-halo mass fraction. Around one hundred velocity measurements per kiloparsec of stream will enable tests for the presence of a local sub-halo density as small as 0.2%-0.5% of the local mass density, with about 1% predicted for 30 kpc orbital radii streams.

  19. Substellar objects around the sdB eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Zhu, Liying; Qian, Shengbang; Liao, Wenping; Zhao, Ergang; Li, Linjia

    2016-07-01

    The sdB-type eclipsing binary consists a very hot subdwarf B (sdB) type primary and a low mass secondary with short period. They are detached binaries and show very narrow eclipse profiles, which benefits the determination of the precise eclipse times. With the precise times of light minimum, we can detected small mass objects around them by analyzing the observed-calculated (O-C) curve based on the light time effect. For searching the substellar objects orbiting around the binaries, we have monitored sdB-type eclipsing binaries for decades. A group of brown dwarfs and planets have been detected since then. In the present paper, we focus on the target NSVS07826147, which may be another exoplanet host candidate among the group of the sdB-type eclipsing binaries.

  20. Photometric Survey to Search for Field sdO Pulsators

    NASA Astrophysics Data System (ADS)

    Johnson, C.; Green, E.; Wallace, S.; O'Malley, C.; Amaya, H.; Biddle, L.; Fontaine, G.

    2014-04-01

    We present the results of a campaign to search for subdwarf O (sdO) star pulsators among bright field stars. The motivation for this project is the recent discovery by Randall et al. (2011) of four rapidly pulsating sdO stars in the globular cluster ω Cen, with Teff near 50,000 K, 5.4 < log g < 6.0, and hydrogen-rich atmospheres. The only previously known sdO pulsator is significantly hotter at 68,500 K and log g = 6.1. All of the sdO pulsators identified so far are fainter than V≍17.4 and, thus, are poor candidates for an in-depth follow-up with asteroseismology. We therefore obtained high S/N light curves and spectroscopy for a number of field sdO stars to attempt to discover bright counterparts to these stars, particularly the ω Cen pulsators. Our primary sample consisted of 19 sdO stars with hydrogen-rich atmospheres, log N(He)/N(H) < -1.0, effective temperatures in the range 40,000 K < Teff < 67,000 K, and surface gravities 5.3 < log g < 6.1. We also observed 17 additional helium-rich sdO stars with log N(He)/N(H) > -0.1 and similar temperatures and gravities. To date, we have found no detectable pulsations at amplitudes above 0.08% (4 times the mean noise level) in any of the 36 field sdO stars that we observed. The presence of pulsations in ω Cen sdO stars and their apparent absence in seemingly comparable field sdO stars is perplexing. While very suggestive, the significance of this result is difficult to assess more completely right now due to remaining uncertainties about the temperature width and purity of the ω Cen instability strip and the existence of any sdO pulsators with weaker amplitudes than the current detection limit in globular clusters.

  1. Composite particle representation for light sd shell nuclei

    SciTech Connect

    Collinson, D.F.

    1986-01-01

    The Composite Particle Representation is applied to light sd shell nuclei /sup 20/O, /sup 20/F and /sup 20/Ne. The energy spectrum is found to agree exactly with the shell model in all cases. The CPR theory is then used to examine the possible boson structure of sd shell wavefunctions. Only in the case of /sup 20/O are the wavefunctions found to have a high boson probability.

  2. Triaxial Earth's rotation: Chandler wobble, free core nutation and diurnal polar motion (Abstract)

    NASA Astrophysics Data System (ADS)

    Sun, R.; Shen, W.-B.

    2015-08-01

    In this study, we formulate two-layered triaxial Earth rotation theory, focusing on the influence of the triaxiality on the Chandler wobble (CW), free core nutation (FCN) and diurnal polar motion. We estimate the frequencies of the normal modes CW and FCN, and results show that though the influence of two-layer triaxiality on the CW and FCN frequencies are very small, there appear some new natures. The response of the Earth's polar motion to the excitation consists of two parts. One is in response to the same frequency excitation and the other is in response to the opposite frequency excitation. For an Earth model with triaxial mantle and core, both of these two parts have four resonant frequencies rather than two that are suggested by rotational symmetric Earth model. However, due to the small strength of these new resonances, the effects of these resonances are only significant when the excitation frequencies are very near to these resonance frequencies. In addition, compared to the biaxial case, the influences of the triaxiality on the prograde and retrograde diurnal polar motions excited by ocean tide component K1 are estimated as - 1.4 μas and - 0.9 μas respectively, which should be taken into account in theory. This study is supported by National 973 Project China (grant No. 2013CB733305), NSFC (grant Nos. 41174011, 41210006, 41128003, 41021061).

  3. Purification, Characterization, and Optimum Conditions of Fermencin SD11, a Bacteriocin Produced by Human Orally Lactobacillus fermentum SD11.

    PubMed

    Wannun, Phirawat; Piwat, Supatcharin; Teanpaisan, Rawee

    2016-06-01

    Fermencin SD11, a bacteriocin produced by human orally Lactobacillus fermentum SD11, was purified, characterized, and optimized in conditions for bacterial growth and bacteriocin production. Fermencin SD11 was purified using three steps of ammonium sulfate precipitation, gel filtration chromatography, and reverse-phase high-performance liquid chromatography. The molecular weight was found to be 33,000 Da using SDS-PAGE and confirmed as 33,593.4 Da by liquid chromatography-mass spectrometry. Fermencin SD11 exhibited activity against a wide range of oral pathogens including cariogenic and periodontogenic pathogens and Candida. The active activity was stable between 60 - 80 °C in a pH range of 3.0 to 7.0. It was sensitive to proteolytic enzymes (proteinase K and trypsin), but it was not affected by α-amylase, catalase, lysozyme, and saliva. The optimum conditions for growth and bacteriocin production of L. fermentum SD11 were cultured at acidic with pH of 5.0-6.0 at 37 or 40 °C under aerobic or anaerobic conditions for 12 h. It is promising that L. fermentum SD11 and its bacteriocin may be an alternative approach for promoting oral health or prevention of oral diseases, e.g., dental caries and periodontitis, which would require further clinical trials. PMID:26892008

  4. Increased rigidly triaxial deformations in neutron-rich Mo, Ru isotopes

    NASA Astrophysics Data System (ADS)

    Liang, WuYang; Jiao, ChangFeng; Xu, FuRong; Fu, XiMing

    2016-09-01

    Pairing-deformation-frequency self-consistent crankingWoods-Saxon model is employed to investigate the triaxiality in the ground states of the neutron-rich even-even Mo, Ru isotopes. Deformation evolutions and transition probabilities have been studied, giving the triaxial shapes in their ground states. The kinematic moments of inertia have been calculated to illustrate the gradually rigid deformation. To understand the origin of the asymmetry shape in this region, we analyze the evolution of single-particle orbits with changing γ deformation. The present calculations reveal the importance of the triaxial deformation in describing not only static property, but also rotational behaviors in this mass region, providing significant probes into the shell structure around.

  5. Validation of triaxial accelerometers to measure the lying behaviour of adult domestic horses.

    PubMed

    DuBois, C; Zakrajsek, E; Haley, D B; Merkies, K

    2015-01-01

    Examining the characteristics of an animal's lying behaviour, such as frequency and duration of lying bouts, has become increasingly relevant for animal welfare research. Triaxial accelerometers have the advantage of being able to continuously monitor an animal's standing and lying behaviour without relying on live observations or video recordings. Multiple models of accelerometers have been validated for use in monitoring dairy cattle; however, no units have been validated for use in equines. This study tested Onset Pendant G data loggers attached to the hind limb of each of two mature Standardbred horses for a period of 5 days. Data loggers were set to record their position every 20 s. Horses were monitored via live observations during the day and by video recordings during the night to compare activity against accelerometer data. All lying events occurred overnight (three to five lying bouts per horse per night). Data collected from the loggers was converted and edited using a macro program to calculate the number of bouts and the length of time each animal spent lying down by hour and by day. A paired t-test showed no significant difference between the video observations and the output from the data loggers (P=0.301). The data loggers did not distinguish standing hipshot from standing square. Predictability, sensitivity, and specificity were all >99%. This study has validated the use of Onset Pendant G data loggers to determine the frequency and duration of standing and lying bouts in adult horses when set to sample and register readings at 20 s intervals. PMID:25273864

  6. Microwave Spectrum of the SD+3 Ion: Molecular Structure.

    PubMed

    Araki; Ozeki; Saito

    1998-11-01

    The J = 1-0 to 4-3 spectral lines of SD+3 were measured in the 152-610 GHz region using a source-modulated microwave spectrometer. The SD+3 ion was generated in a free space absorption cell by a hollow-cathode discharge in a gas mixture of D2S and D2. The rotational constant B0 and the centrifugal distortion constants DJ and DJK were determined from the measured frequencies. A vibration-rotation analysis was carried out and the rz structures of SH+3 and SD+3 were derived from their zero point averaged rotational constants, expressed as SH+3: rz = 1.36512(22) Å and thetaz = 94.098(26) degrees, and SD+3: rz = 1.36086(16) Å and thetaz = 94.1211(195) degrees, where the difference between thetaz(HSH) and thetaz(DSD) was assumed to be the same as that between thetaz(HPH) of PH3 and thetaz(DPD) of PD3. From the shift between the rz structures of SH+3 and SD+3, the re structure of SH+3 was estimated to be re = 1.35001(113) Å, thetae = 94.181(135) degrees. Copyright 1998 Academic Press. PMID:9770407

  7. Decay out of SD Band in ^192Pb

    NASA Astrophysics Data System (ADS)

    McNabb, D. P.; Cizewski, J. A.; Ding, K. Y.; Fotiades, N.; Archer, D. E.; Becker, J. A.; Bernstein, L. A.; Hauschild, K.; Younes, W.; Clark, R. M.; Fallon, P.; Lee, I. Y.; Macchiavelli, A. O.; MacLeod, R. W.

    1997-04-01

    Gamma-ray transitions linking the yrast SD bands to the known (ND) levels have been found in ^194Pb(M. J. Brinkman, et al., Phys. Rev. C53), R1461 (1996), A. Lopez-Martens, et al., Phys. Lett. B380, 18 (1996) and K. Hauschild, et al., submitted to Phys. Rev. C (1996). and ^194Hg.(T. L. Khoo, et al., Phys. Rev. Lett. 76), 1583 (1996). The spin, parity and excitation energy of these SD bands were established. Linking transitions are understood as arising from ND states nearby in excitation energy which are admixed with the SD states.(E. Vigezzi, et al., Phys. Lett. B249), 163 (1990). We anticipate a smaller phase space for quasicontinuous decay of the SD band in ^192Pb because it is predicted to lie lower in excitation than the SD band in ^194Pb.footnote S. J. Krieger, et al. Nucl. Phys. A542, 43 (1992). To search for linking transitions in ^192Pb we used the Gammasphere array at LBNL and the ^24Mg(^173Yb,5n) reaction at 134 MeV. Candidates for linking transitions and general features of the decay will be discussed.

  8. SD-CAS: Spin Dynamics by Computer Algebra System.

    PubMed

    Filip, Xenia; Filip, Claudiu

    2010-11-01

    A computer algebra tool for describing the Liouville-space quantum evolution of nuclear 1/2-spins is introduced and implemented within a computational framework named Spin Dynamics by Computer Algebra System (SD-CAS). A distinctive feature compared with numerical and previous computer algebra approaches to solving spin dynamics problems results from the fact that no matrix representation for spin operators is used in SD-CAS, which determines a full symbolic character to the performed computations. Spin correlations are stored in SD-CAS as four-entry nested lists of which size increases linearly with the number of spins into the system and are easily mapped into analytical expressions in terms of spin operator products. For the so defined SD-CAS spin correlations a set of specialized functions and procedures is introduced that are essential for implementing basic spin algebra operations, such as the spin operator products, commutators, and scalar products. They provide results in an abstract algebraic form: specific procedures to quantitatively evaluate such symbolic expressions with respect to the involved spin interaction parameters and experimental conditions are also discussed. Although the main focus in the present work is on laying the foundation for spin dynamics symbolic computation in NMR based on a non-matrix formalism, practical aspects are also considered throughout the theoretical development process. In particular, specific SD-CAS routines have been implemented using the YACAS computer algebra package (http://yacas.sourceforge.net), and their functionality was demonstrated on a few illustrative examples. PMID:20843716

  9. True Triaxial Strength and Failure Modes of Cubic Rock Specimens with Unloading the Minor Principal Stress

    NASA Astrophysics Data System (ADS)

    Li, Xibing; Du, Kun; Li, Diyuan

    2015-11-01

    True triaxial tests have been carried out on granite, sandstone and cement mortar using cubic specimens with the process of unloading the minor principal stress. The strengths and failure modes of the three rock materials are studied in the processes of unloading σ 3 and loading σ 1 by the newly developed true triaxial test system under different σ 2, aiming to study the mechanical responses of the rock in underground excavation at depth. It shows that the rock strength increases with the raising of the intermediate principal stress σ 2 when σ 3 is unloaded to zero. The true triaxial strength criterion by the power-law relationship can be used to fit the testing data. The "best-fitting" material parameters A and n ( A > 1.4 and n < 1.0) are almost located in the same range as expected by Al-Ajmi and Zimmerman (Int J Rock Mech Min Sci 563 42(3):431-439, 2005). It indicates that the end effect caused by the height-to-width ratio of the cubic specimens will not significantly affect the testing results under true triaxial tests. Both the strength and failure modes of cubic rock specimens under true triaxial unloading condition are affected by the intermediate principal stress. When σ 2 increases to a critical value for the strong and hard rocks (R4, R5 and R6), the rock failure mode may change from shear to slabbing. However, for medium strong and weak rocks (R3 and R2), even with a relatively high intermediate principal stress, they tend to fail in shear after a large amount of plastic deformation. The maximum extension strain criterion Stacey (Int J Rock Mech Min Sci Geomech Abstr 651 18(6):469-474, 1981) can be used to explain the change of failure mode from shear to slabbing for strong and hard rocks under true triaxial unloading test condition.

  10. Analytical determination of the time dependences of the drifts of a triaxial gyrostabilizer

    NASA Astrophysics Data System (ADS)

    Sokolov, S. V.

    1992-12-01

    For a triaxial gyrostabilizer platform located on the ground, equations are obtained which describe the change in time of the instantaneous speed of rotation of the platform in gyroscopic coordinates in the context of the precession theory. An approximation of these equations based on the properties of the gyrostabilizer and its application is considered, and analytical expressions are derived for the time dependence of the drift of the gyrostabilized platform. The results obtained significantly simplify the solution of the problem of identifying the parameters of the triaxial gyrostabilizer and estimating its current orientation in selected coordinates in an inertial navigation system.

  11. Evaluation of uniaxial and triaxial shock isolation techniques for a piezoresistive accelerometer

    SciTech Connect

    Bateman, V.I.; Bell, R.G. III; Brown, F.A.; Davie, N.T.; Nusser, M.A.

    1990-01-01

    Development of both uniaxial and triaxial shock isolation techniques for pyroshock and impact tests has continued this year. The uniaxial shock isolation technique has demonstrated acceptable characteristics for a temperature range of {minus}50{degrees}F to +186{degrees}F and a frequency bandwidth of DC to 10 kHz. The triaxial shock isolation technique has demonstrated acceptable results for a temperature range of {minus}50{degrees}F to 70{degrees}F and a frequency bandwidth of DC to 10 kHz. 5 refs., 7 figs.

  12. Analysis and experimental validation of a triaxial antenna for microwave tumor ablation.

    PubMed

    Brace, Christopher L; van der Weide, Daniel W; Lee, Fred T; Laeseke, Paul F; Sampson, Lisa

    2004-06-01

    We apply a new triaxial antenna for microwave ablation procedures. The antenna consists of a coaxial monopole inserted through an 18-gauge biopsy needle positioned one quarter-wavelength from the antenna base. The biopsy needle creates a triaxial structure, which enhances return loss by more than 10 dB, thus limiting return currents along the feed line. Numerical simulations are used to optimize the antenna design. Numerical and ex-vivo experimental results are presented to quantify the field distribution, heating pattern and return loss of the antenna. PMID:18079982

  13. Compression response of tri-axially braided textile composites

    NASA Astrophysics Data System (ADS)

    Song, Shunjun

    2007-12-01

    This thesis is concerned with characterizing the compression stiffness and compression strength of 2D tri-axially braided textile composites (2DTBC). Two types of 2DTBC are considered differing only on the resin type, while the textile fiber architecture is kept the same with bias tows at 45 degrees to the axial tows. Experimental, analytical and computational methods are described based on the results generated in this study. Since these composites are manufactured using resin transfer molding, the intended and as manufactured composite samples differ in their microstructure due to consolidation and thermal history effects in the manufacturing cycle. These imperfections are measured and the effect of these imperfections on the compression stiffness and strength are characterized. Since the matrix is a polymer material, the nonuniform thermal history undergone by the polymer at manufacturing (within the composite and in the presence of fibers) renders its properties to be non-homogenous. The effects of these non-homogeneities are captured through the definition of an equivalent in-situ matrix material. A method to characterize the mechanical properties of the in-situ matrix is also described. Fiber tow buckling, fiber tow kinking and matrix microcracking are all observed in the experiments. These failure mechanisms are captured through a computational model that uses the finite element (FE) technique to discretize the structure. The FE equations are solved using the commercial software ABAQUS version 6.5. The fiber tows are modeled as transversely isotropic elastic-plastic solids and the matrix is modeled as an isotropic elastic-plastic solid with and without microcracking damage. Because the 2DTBC is periodic, the question of how many repeat units are necessary to model the compression stiffness and strength are examined. Based on the computational results, the correct representative unit cell for this class of materials is identified. The computational models and

  14. Multiple chiral doublet candidate nucleus {sup 105}Rh in a relativistic mean-field approach

    SciTech Connect

    Li Jian; Zhang, S. Q.; Meng, J.

    2011-03-15

    Following the reports of two pairs of chiral doublet bands observed in {sup 105}Rh, the adiabatic and configuration-fixed constrained triaxial relativistic mean-field calculations are performed to investigate their triaxial deformations with the corresponding configuration and the possible multiple chiral doublet (M{chi}D) phenomenon. The existence of the M{chi}D phenomenon in {sup 105}Rh is highly expected.

  15. 78 FR 39820 - Standing Rock Sioux Tribe Disaster #SD-00058

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-02

    ... ADMINISTRATION Standing Rock Sioux Tribe Disaster SD-00058 AGENCY: U.S. Small Business Administration. ACTION... Assistance Only for the Standing Rock Indian Reservation (FEMA-4123-DR), dated 06/25/2013. Incident: Severe... adversely affected by the disaster: Primary Area: Standing Rock Indian Reservation. The Interest Rates...

  16. 75 FR 4417 - Wind Cave National Park, Custer County, SD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-27

    ... Wind Cave National Park, Custer County, SD AGENCY: National Park Service. ACTION: Notice of... Statement, Wind Cave National Park, Custer County, South Dakota. SUMMARY: Pursuant to Section 102(2)(C) of... Environmental Impact Statement (Plan), Wind Cave National Park, Custer County, South Dakota. On December 3,...

  17. 76 FR 35935 - South Dakota Disaster Number SD-00041

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-20

    ... From the Federal Register Online via the Government Publishing Office U.S. SMALL BUSINESS ADMINISTRATION South Dakota Disaster Number SD-00041 AGENCY: U.S. Small Business Administration. ACTION... completed loan applications to: U.S. Small Business Administration, Processing and Disbursement...

  18. 76 FR 35936 - South Dakota Disaster Number SD-00041

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-20

    ... From the Federal Register Online via the Government Publishing Office U.S. SMALL BUSINESS ADMINISTRATION South Dakota Disaster Number SD-00041 AGENCY: U.S. Small Business Administration. ACTION... completed loan applications to: U.S. Small Business Administration, Processing and Disbursement...

  19. 78 FR 29425 - South Dakota Disaster #SD-00057

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-20

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION South Dakota Disaster SD-00057 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY... State of South Dakota (FEMA-4115-DR), dated 05/10/2013. Incident: Severe Winter Storm and...

  20. 76 FR 40767 - South Dakota Disaster Number SD-00041

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-11

    ... ADMINISTRATION South Dakota Disaster Number SD-00041 AGENCY: U.S. Small Business Administration. ACTION... Assistance Only for the State of South Dakota (FEMA-1984-DR), dated 05/13/2011. Incident: Flooding. Incident... Non-Profit organizations in the State of South Dakota, dated 05/13/2011, is hereby amended to...

  1. 75 FR 19435 - South Dakota Disaster Number SD-00027

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-14

    ... ADMINISTRATION South Dakota Disaster Number SD-00027 AGENCY: Small Business Administration. ACTION: Amendment 1... Only for the State of South Dakota (FEMA-1886-DR), dated 03/09/2010. Incident: Severe Winter Storm and... State of South Dakota, dated 03/09/2010, is hereby amended to include the following areas as...

  2. 75 FR 13145 - SOUTH DAKOTA Disaster #SD-00027

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-18

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION SOUTH DAKOTA Disaster SD-00027 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY... State of South Dakota (FEMA-1886-DR), dated 03/09/2010. Incident: Severe Winter Storm and...

  3. 76 FR 54520 - South Dakota Disaster #SD-00042

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-01

    ... ADMINISTRATION South Dakota Disaster SD-00042 AGENCY: U.S. Small Business Administration. ACTION: Notice. ] SUMMARY: This is a Notice of the Presidential declaration of a major disaster for the State of South... Injury Loans Only): South Dakota: Aurora, Bon Homme, Brule, Clay, Dewey, Douglas, Gregory,...

  4. 75 FR 39994 - South Dakota Disaster Number SD-00031

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-13

    ... ADMINISTRATION South Dakota Disaster Number SD-00031 AGENCY: U.S. Small Business Administration. ACTION... Assistance Only for the State of South Dakota (FEMA-1915-DR), dated 05/13/2010. Incident: Flooding. Incident... Non-Profit organizations in the State of South Dakota, dated 05/13/2010, is hereby amended to...

  5. 75 FR 28311 - South Dakota Disaster # SD-00031

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-20

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION South Dakota Disaster SD-00031 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY... State of South Dakota (FEMA--1915--DR), dated 05/13/2010. Incident: Flooding. Incident Period:...

  6. 75 FR 61229 - South Dakota Disaster #SD-00034

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-04

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION South Dakota Disaster SD-00034 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY... State of South Dakota (FEMA-1938-DR), dated 09/23/2010. Incident: Severe Storms and Flooding....

  7. 76 FR 30226 - South Dakota Disaster # SD-00041

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-24

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION South Dakota Disaster SD-00041 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY... State of South Dakota (FEMA-1984-DR), dated 05/13/2011. Incident: Flooding. Incident Period:...

  8. 75 FR 30873 - South Dakota Disaster Number SD-00031

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-02

    ... ADMINISTRATION South Dakota Disaster Number SD-00031 AGENCY: U.S. Small Business Administration. ACTION... Assistance Only for the State of South Dakota (FEMA-1915-DR), dated 05/13/2010. Incident: Flooding. Incident... Non-Profit organizations in the State of South Dakota, dated 05/13/2010, is hereby amended to...

  9. 75 FR 38154 - South Dakota Disaster Number SD-00031

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-01

    ... ADMINISTRATION South Dakota Disaster Number SD-00031 AGENCY: U.S. Small Business Administration. ACTION... Assistance Only for the State of SOUTH DAKOTA (FEMA-1915-DR), dated 05/13/2010. Incident: Flooding. Incident... Non-Profit organizations in the State of SOUTH DAKOTA, dated 05/13/2010, is hereby amended...

  10. 75 FR 28312 - South Dakota Disaster # SD-00030

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-20

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION South Dakota Disaster SD-00030 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY... State of South Dakota (FEMA-1914-DR), dated 05/13/2010. Incident: Severe Winter Storm. Incident...

  11. 75 FR 47035 - South Dakota Disaster #SD-00033

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-04

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION South Dakota Disaster SD-00033 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY... State of South Dakota (FEMA-1929-DR), dated 07/29/2010. Incident: Severe storms, tornadoes, and...

  12. 75 FR 69732 - South Dakota Disaster #SD-00035

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-15

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION South Dakota Disaster SD-00035 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY... State of South Dakota (FEMA-1947-DR), dated 11/02/2010. Incident: Severe Storms and Flooding....

  13. 77 FR 46284 - Amendment of Class E Airspace; Lemmon, SD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-03

    ...: Authority: 49 U.S.C. 106(g), 40103, 40113, 40120; E. O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389... Federal Aviation Administration 14 CFR Part 71 Amendment of Class E Airspace; Lemmon, SD AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action amends Class E airspace...

  14. 76 FR 40597 - Amendment of Class E Airspace; Madison, SD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-11

    ...), 40103, 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 0 2. The... Federal Aviation Administration 14 CFR Part 71 Amendment of Class E Airspace; Madison, SD AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action amends Class E airspace...

  15. 78 FR 41837 - Establishment of Class E Airspace; Parkston, SD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-12

    ..., 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389. Sec. 71.1 0 2. The incorporation... Federal Aviation Administration 14 CFR Part 71 Establishment of Class E Airspace; Parkston, SD AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This action establishes Class...

  16. 78 FR 48764 - South Dakota Disaster # SD-00061

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-09

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION South Dakota Disaster SD-00061 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY...: Submit completed loan applications to: U.S. Small Business Administration, Processing and...

  17. Experimental Study on Properties of Methane Diffusion of Coal Block under Triaxial Compressive Stress

    PubMed Central

    Zhao, Hong-Bao

    2014-01-01

    Taking the standard size coal block samples defined by ISRM as research objects, both properties of methane diffusion of coal block under triaxial compressive stress and characteristic influences caused by methane pressure were systematically studied with thermo-fluid-solid coupling with triaxial servocontrolled seepage equipment of methane-containing coal. The result shows the methane diffusion property of coal block under triaxial compressive stress was shown in four-stage as follow, first is sharply reduce stage, second is hyperbolic reduce stage, third is close to a fixed value stage, fourth stage is 0. There is a special point making the reduced rate of characteristic curve of methane diffusion speed become sharply small; the influences of shape of methane diffusion speed characteristic curve caused by methane pressure are not obvious, which only is shown in numerical size of methane diffusion speed. Test time was extended required by appear of the special point makes the reduce rate of methane diffusion speed become sharply small. The fitting four-phase relation of methane diffusion of coal block under triaxial compressive stress was obtained, and the idea is proposed that influences of the fitting four-phase relation caused by methane pressure were only shown in value of fitting parameters. PMID:25531000

  18. Simulation of a true-triaxial deformation test on anisotropic gneiss using FLAC3D

    NASA Astrophysics Data System (ADS)

    Ye, Shenghua; Sehizadeh, Mehdi; Nasseri, Mohammad; Young, Paul

    2016-04-01

    A series of true-triaxial experiments have been carried out at the University of Toronto's Rock Fracture Dynamics Laboratory. Isotropic pegmatite and gneiss have been used to systematically study the effect of anisotropy on the strength, behaviour and seismic response. Samples were loaded under true-triaxial stress conditions and subjected to complex loading and unloading histories associated with rock deformation around underground openings. The results show expected patterns of weakness from preferentially oriented samples and highlight the importance of unloading history under true-triaxial conditions on the deformation and seismic response of the samples. These tests have been used to validate a synthetic simulation using the Itasca FLAC3D numerical code. The paper describes the FLAC3D simulations of the complex true-triaxial loading and unloading history of the different anisotropic samples. Various parameters were created to describe the physico-mechanical properties of the synthetic rock samples. Foliation planes of preferential orientations with respect to the primary loading direction were added to the synthetic rock samples to reflect the anisotropy of the gneiss. These synthetic rock samples were subjected to the same loading and unloading paths as the real rock samples, and failed in the same mechanism as what was observed from the experiments, and thus it proved the validity of this numerical simulation with FLAC3D.

  19. Mechanical properties of compacted lunar simulant using new vacuum triaxial equipment

    NASA Technical Reports Server (NTRS)

    Desai, Chandra S.; Saadatmanesh, Hamid; Allen, Tom

    1992-01-01

    Mechanical stress-strain strength properties of Arizona Lunar Simulant (ALS) are investigated by using a newly developed vacuum triaxial device that allows compaction under different initial vacuums and confinements. Influence of vacuum and confinement on compaction, strength and deformation characteristics of compacted material are delineated and discussed.

  20. An Application Using Triaxial Ellipsoids to Model Martian Dust at the Phoenix Landing Site

    NASA Astrophysics Data System (ADS)

    Mason, E. L.; Lemmon, M. T.

    2014-12-01

    Martian atmospheric dust is not spherical and contains irregular shaped particles. This irregularity adds complexity to models determining radiative heating of the atmosphere. Particle size has been studied extensively with remote sensing, but particle shape is still poorly understood. Bi et al. show that an assortment of triaxial ellipsoids provides a good analog for the scattering properties of terrestrial dust aerosols. In addition Z. Meng et al. (2010) have developed a database containing single-scattering properties of irregularly shaped dust particles with pre-defined microphysical and optical parameters. The tabulation allows quick and efficient use of the results from time-consuming models and can be applied to the Martian atmosphere. The landing site for Phoenix was in a region that fell within the northern seasonal ice cap and was active during a period of large dust upwelling. The lander's Surface Stereo Imager performed several cross-sky brightness surveys to constrain the size distribution and scattering and absorption properties of the airborne dust in the Martian northern polar environment. Using the database, single scattering properties adapted to the Martian atmosphere can be used to determine bulk scattering properties of the medium at the Phoenix landing site. We will present a comparison of triaxial ellipsoids with spheroidal models using Phoenix spectrophotometric data and show that triaxial ellipsoid properties can produce a good fit to the observed data. In addition we will provide initial results of polarization to test the triaxial ellipsoid hypothesis.

  1. A highly triaxial N-body system tumbling about is intermediate axis

    NASA Technical Reports Server (NTRS)

    Duncan, Martin J.; Levison, Harold F.

    1989-01-01

    The results are presented of an N-body simulation which shows that it is possible for a highly triaxial self-gravitating system in dynamical equilibrium to exhibit stable figure rotation about its intermediate axis. The system is long-lived, lasting at least 20 half-mass crossing times of the final system. The nature of the simulation is summarized.

  2. Experimental study on properties of methane diffusion of coal block under triaxial compressive stress.

    PubMed

    Zhao, Hong-Bao

    2014-01-01

    Taking the standard size coal block samples defined by ISRM as research objects, both properties of methane diffusion of coal block under triaxial compressive stress and characteristic influences caused by methane pressure were systematically studied with thermo-fluid-solid coupling with triaxial servocontrolled seepage equipment of methane-containing coal. The result shows the methane diffusion property of coal block under triaxial compressive stress was shown in four-stage as follow, first is sharply reduce stage, second is hyperbolic reduce stage, third is close to a fixed value stage, fourth stage is 0. There is a special point making the reduced rate of characteristic curve of methane diffusion speed become sharply small; the influences of shape of methane diffusion speed characteristic curve caused by methane pressure are not obvious, which only is shown in numerical size of methane diffusion speed. Test time was extended required by appear of the special point makes the reduce rate of methane diffusion speed become sharply small. The fitting four-phase relation of methane diffusion of coal block under triaxial compressive stress was obtained, and the idea is proposed that influences of the fitting four-phase relation caused by methane pressure were only shown in value of fitting parameters. PMID:25531000

  3. Destructive interference of E2 matrix elements in a triaxial rotor model

    SciTech Connect

    Allmond, James M; Wood, J. L.; Kulp, W. D.

    2010-01-01

    A triaxial rotor model with independent inertia and electric quadrupole tensors is applied to nuclei that have certain E2 matrix elements equal to zero. It is shown that such vanishing E2 matrix elements are explained by the model as a destructive interference effect. The example of 196Pt is considered.

  4. Features of the Kaiser effect in coal specimens at different stages of the triaxial axisymmetric deformation

    SciTech Connect

    Shkuratnik, V.L.; Filimonov, Y.L.; Kuchurin, S.V.

    2007-01-15

    The experimental data are presented for the features of formation and manifestation of the acoustic-emission and deformation memory effects in specimens of anthracite at different stages of the triaxial cyclic deformation by the Karman scheme in the pre-limiting and post-limiting zones.

  5. Acoustic-emissive memory effect in coal samples under triaxial axial-symmetric compression

    SciTech Connect

    Shkuratnik, V.L.; Filimonov, Y.L.; Kuchurin, S.V.

    2006-05-15

    The experimental data are presented for production and manifestation of the Kaiser effect in coal samples subjected to triaxial loading by the Karman scheme in the first cycle and to various loading modes in the second cycle. The Kaiser effect is identified with the help of a deformation memory effect.

  6. Automated segmentation of serous pigment epithelium detachment in SD-OCT images

    NASA Astrophysics Data System (ADS)

    Sun, Zhuli; Shi, Fei; Xiang, Dehui; Chen, Haoyu; Chen, Xinjian

    2015-03-01

    Pigment epithelium detachment (PED) is an important clinical manifestation of multiple chorio-retinal disease processes, which can cause the loss of central vision. A 3-D method is proposed to automatically segment serous PED in SD-OCT images. The proposed method consists of five steps: first, a curvature anisotropic diffusion filter is applied to remove speckle noise. Second, the graph search method is applied for abnormal retinal layer segmentation associated with retinal pigment epithelium (RPE) deformation. During this process, Bruch's membrane, which doesn't show in the SD-OCT images, is estimated with the convex hull algorithm. Third, the foreground and background seeds are automatically obtained from retinal layer segmentation result. Fourth, the serous PED is segmented based on the graph cut method. Finally, a post-processing step is applied to remove false positive regions based on mathematical morphology. The proposed method was tested on 20 SD-OCT volumes from 20 patients diagnosed with serous PED. The average true positive volume fraction (TPVF), false positive volume fraction (FPVF), dice similarity coefficient (DSC) and positive predictive value (PPV) are 97.19%, 0.03%, 96.34% and 95.59%, respectively. Linear regression analysis shows a strong correlation (r = 0.975) comparing the segmented PED volumes with the ground truth labeled by an ophthalmology expert. The proposed method can provide clinicians with accurate quantitative information, including shape, size and position of the PED regions, which can assist diagnose and treatment.

  7. Carbon abundances of sdO stars from SPY

    NASA Astrophysics Data System (ADS)

    Hirsch, Heiko; Heber, Uli

    2009-06-01

    Ströer et al. (2007) recently suggested a classification of sdOs according to supersolar and subsolar helium abundances, with only the helium-enriched stars showing signes of carbon and/or nitrogen in their optical spectra. We aim to derive reliable carbon and nitrogen abundances by fitting synthetic spectra to data obtained with the UVES spectrograph at ESO. Here we present our first results of the analysis of carbon abundances in hot subdwarf O stars. By constructing a grid of model atmospheres consisting of hydrogen, helium and carbon we were able to derive atmospheric parameters of nine carbon rich sdOs. We find log(NC/Ntotal) up to ten times higher than the solar value, while the mean value for the effective temperature and the surface gravity is slightly lower than derived by helium-hydrogen models only. Surprisingly, we also find three fast rotators among our program stars.

  8. Shell Model Depiction of Isospin Mixing in sd Shell

    SciTech Connect

    Lam, Yi Hua; Smirnova, Nadya A.; Caurier, Etienne

    2011-11-30

    We constructed a new empirical isospin-symmetry breaking (ISB) Hamiltonian in the sd(1s{sub 1/2}, 0d{sub 5/2} and 0d{sub 3/2}) shell-model space. In this contribution, we present its application to two important case studies: (i){beta}-delayed proton emission from {sup 22}Al and (ii) isospin-mixing correction to superallowed 0{sup +}{yields}0{sup +}{beta}-decay ft-values.

  9. Gray-shading for the SD-4060 graphics device

    NASA Technical Reports Server (NTRS)

    Gloeckler, C.

    1975-01-01

    Grays, a FORTRAN program, is described which will generate gray shading for the SD-4060 graphics device. The program produces 10 shades of gray ranging from no shading at all to complete coverage of the film frame. The graphing capabilities are summarized and illustrated. The figures displayed are representative of the microfilm output, but the distinction between various intensities is much clearer on the film, especially at the more intense shading.

  10. Comparisons of interacting-boson-fermion approximation and triaxial calculations for odd-mass N =80 nuclei

    SciTech Connect

    Aryaeinejad, R.; Chou, W.; McHarris, W.C. )

    1989-09-01

    The interacting-boson-fermion-approximation and triaxial models were used to calculate excitation energies and mixing ratios for the {ital N}=80 nuclei, {sup 139}Pr, {sup 141}Pm, and {sup 143}Eu. For low-lying negative- and positive-parity states both models yield roughly the same numbers, in good agreement with experimental results. For high-lying states we find that the interacting-boson-fermion-approximation model describes the level structure considerably better than the triaxial model. On the other hand, the triaxial model gives more satisfactory results in predicting the mixing ratios.

  11. Sex differences in the stress response in SD rats.

    PubMed

    Lu, Jing; Wu, Xue-Yan; Zhu, Qiong-Bin; Li, Jia; Shi, Li-Gen; Wu, Juan-Li; Zhang, Qi-Jun; Huang, Man-Li; Bao, Ai-Min

    2015-05-01

    Sex differences play an important role in depression, the basis of which is an excessive stress response. We aimed at revealing the neurobiological sex differences in the same study in acute- and chronically-stressed rats. Female Sprague-Dawley (SD) rats were randomly divided into 6 groups: chronic unpredictable mild stress (CUMS), acute foot shock (FS) and controls, animals in all 3 groups were sacrificed in proestrus or diestrus. Male SD rats were randomly divided into 3 groups: CUMS, FS and controls. Comparisons were made of behavioral changes in CUMS and control rats, plasma levels of corticosterone (CORT), testosterone (T) and estradiol (E2), and of the hypothalamic mRNA-expression of stress-related molecules, i.e. estrogen receptor α and β, androgen receptor, aromatase, mineralocorticoid receptor, glucocorticoid receptor, corticotropin-releasing hormone, arginine vasopressin and oxytocin. CUMS resulted in disordered estrus cycles, more behavioral and hypothalamic stress-related molecules changes and a stronger CORT response in female rats compared with male rats. Female rats also showed decreased E2 and T levels after FS and CUMS, while male FS rats showed increased E2 and male CUMS rats showed decreased T levels. Stress affects the behavioral, endocrine and the molecular response of the stress systems in the hypothalamus of SD rats in a clear sexual dimorphic way, which has parallels in human data on stress and depression. PMID:25687843

  12. Complex dynamics of an archetypal self-excited SD oscillator driven by moving belt friction

    NASA Astrophysics Data System (ADS)

    Zhi-Xin, Li; Qing-Jie, Cao; Léger, Alain

    2016-01-01

    We propose an archetypal self-excited system driven by moving belt friction, which is constructed with the smooth and discontinuous (SD) oscillator proposed by the Cao et al. and the classical moving belt. The moving belt friction is modeled as the Coulomb friction to formulate the mathematical model of the proposed self-excited SD oscillator. The equilibrium states of the unperturbed system are obtained to show the complex equilibrium bifurcations. Phase portraits are depicted to present the hyperbolic structure transition, the multiple stick regions, and the friction-induced asymmetry phenomena. The numerical simulations are carried out to demonstrate the friction-induced vibration of multiple stick-slip phenomena and the stick-slip chaos in the perturbed self-excited system. The results presented here provide an opportunity for us to get insight into the mechanism of the complex friction-induced nonlinear dynamics in mechanical engineering and geography. Project supported by the National Natural Science Foundation of China (Grant Nos. 11372082 and 11572096) and the National Basic Research Program of China (Grant No. 2015CB057405).

  13. Nanofibers Fabricated Using Triaxial Electrospinning as Zero Order Drug Delivery Systems.

    PubMed

    Yu, Deng-Guang; Li, Xiao-Yan; Wang, Xia; Yang, Jun-He; Bligh, S W Annie; Williams, Gareth R

    2015-08-26

    A new strategy for creating functional trilayer nanofibers through triaxial electrospinning is demonstrated. Ethyl cellulose (EC) was used as the filament-forming matrix in the outer, middle, and inner working solutions and was combined with varied contents of the model active ingredient ketoprofen (KET) in the three fluids. Triaxial electrospinning was successfully carried out to generate medicated nanofibers. The resultant nanofibers had diameters of 0.74 ± 0.06 μm, linear morphologies, smooth surfaces, and clear trilayer nanostructures. The KET concentration in each layer gradually increased from the outer to the inner layer. In vitro dissolution tests demonstrated that the nanofibers could provide linear release of KET over 20 h. The protocol reported in this study thus provides a facile approach to creating functional nanofibers with sophisticated structural features. PMID:26244640

  14. Rotational normal modes of triaxial two-layered anelastic Earth model

    NASA Astrophysics Data System (ADS)

    Yang, Zhuo; Shen, WenBin

    2016-04-01

    This study focuses on providing rotational normal modes of a triaxial two-layered anelastic Earth model with considering the electromagnetic coupling. We formulate the rotation equation of the triaxial two-layered anelastic Earth model and then provide solution of that equation. We obtain four mathematically possible solutions which might exist in reality. Based on present choice of the conventional reference systems, only two of these four solutions correspond to the real existing prograde Chandler wobble (CW) and the retrograde free core nutation (FCN). We provide the periods of CW and FCN as well as their quality factors based on various experiments and observations. This study is supported by National 973 Project China (grant No. 2013CB733305) and NSFC (grant Nos. 41174011, 41210006, 41429401).

  15. Evidence for a Triaxial Milky Way Dark Matter Halo from the Sagittarius Stellar Tidal Stream

    NASA Astrophysics Data System (ADS)

    Law, David R.; Majewski, S. R.; Johnston, K. V.

    2010-01-01

    Observations of the lengthy tidal streams produced by the destruction of the Sagittarius dwarf spheroidal galaxy (Sgr dSph) are capable of providing strong constraints on the shape of the Galactic gravitational potential. However, previous work, based on modeling different stream properties in axisymmetric Galactic models has yielded conflicting results: while the angular precession of the Sgr leading arm is most consistent with a spherical or slightly oblate halo, the radial velocities of stars in this arm are only reproduced by prolate halo models. We demonstrate that this apparent paradox can be resolved by instead adopting a triaxial potential. Our new Galactic halo model, which simultaneously fits all well-established phase space constraints from the Sgr stream, provides the first conclusive evidence for, and tentative measurement of, triaxiality in an individual dark matter halo. In this model, the minor axis of the dark halo is approximately coincident with the Galactic X axis connecting the Sun and the Galactic Center.

  16. DETECTING TRIAXIALITY IN THE GALACTIC DARK MATTER HALO THROUGH STELLAR KINEMATICS

    SciTech Connect

    Rojas-Nino, Armando; Valenzuela, Octavio; Pichardo, Barbara; Aguilar, Luis A. E-mail: barbara@astro.unam.mx

    2012-10-01

    Assuming the dark matter halo of the Milky Way to be a non-spherical potential (i.e., triaxial, prolate, oblate), we show how the assembling process of the Milky Way halo may have left long-lasting stellar halo kinematic fossils due to the shape of the dark matter halo. In contrast with tidal streams, which are associated with recent satellite accretion events, these stellar kinematic groups will typically show inhomogeneous chemical and stellar population properties. However, they may be dominated by a single accretion event for certain mass assembling histories. If the detection of these peculiar kinematic stellar groups were confirmed, they would be the smoking gun for the predicted triaxiality of dark halos in cosmological galaxy formation scenarios.

  17. Microwave Ablation With a Triaxial Antenna: Results in ex vivo Bovine Liver.

    PubMed

    Brace, Christopher L; Laeseke, Paul F; van der Weide, Daniel W; Lee, Fred T

    2005-01-01

    We apply a new triaxial antenna for microwave ablation procedures to an ex vivo bovine liver. The antenna consists of a coaxial monopole inserted through a biopsy needle positioned one quarter-wavelength from the antenna base. The insertion needle creates a triaxial structure, which enhances return loss more than 10 dB, maximizing energy transfer to the tissue while minimizing feed cable heating and invasiveness. Numerical electromagnetic and thermal simulations are used to optimize the antenna design and predict heating patterns. Numerical and ex vivo experimental results show that the lesion size depends strongly on ablation time and average input power, but not on peak power. Pulsing algorithms are also explored. We were able to measure a 3.8-cm lesion using 50 W for 7 min, which we believe to be the largest lesion reported thus far using a 17-gauge insertion needle. PMID:18079981

  18. Automated Drusen Segmentation and Quantification in SD-OCT Images

    PubMed Central

    Chen, Qiang; Leng, Theodore; Zheng, Luoluo; Kutzscher, Lauren; Ma, Jeffrey; de Sisternes, Luis; Rubin, Daniel L.

    2013-01-01

    Spectral domain optical coherence tomography (SD-OCT) is a useful tool for the visualization of drusen, a retinal abnormality seen in patients with age-related macular degeneration (AMD); however, objective assessment of drusen is thwarted by the lack of a method to robustly quantify these lesions on serial OCT images. Here, we describe an automatic drusen segmentation method for SD-OCT retinal images, which leverages a priori knowledge of normal retinal morphology and anatomical features. The highly reflective and locally connected pixels located below the retinal nerve fiber layer (RNFL) are used to generate a segmentation of the retinal pigment epithelium (RPE) layer. The observed and expected contours of the RPE layer are obtained by interpolating and fitting the shape of the segmented RPE layer, respectively. The areas located between the interpolated and fitted RPE shapes (which have nonzero area when drusen occurs) are marked as drusen. To enhance drusen quantification, we also developed a novel method of retinal projection to generate an en face retinal image based on the RPE extraction, which improves the quality of drusen visualization over the current approach to producing retinal projections from SD-OCT images based on a summed-voxel projection (SVP), and it provides a means of obtaining quantitative features of drusen in the en face projection. Visualization of the segmented drusen is refined through several post-processing steps, drusen detection to eliminate false positive detections on consecutive slices, drusen refinement on a projection view of drusen, and drusen smoothing. Experimental evaluation results demonstrate that our method is effective for drusen segmentation. In a preliminary analysis of the potential clinical utility of our methods, quantitative drusen measurements, such as area and volume, can be correlated with the drusen progression in non-exudative AMD, suggesting that our approach may produce useful quantitative imaging biomarkers

  19. The planar restricted three-body problem when both primaries are triaxial rigid bodies: Equilibrium points and periodic orbits

    NASA Astrophysics Data System (ADS)

    Elshaboury, S. M.; Abouelmagd, Elbaz I.; Kalantonis, V. S.; Perdios, E. A.

    2016-09-01

    The restricted three-body problem when the primaries are triaxial rigid bodies is considered and its basic dynamical features are studied. In particular, the equilibrium points are identified as well as their stability is determined in the special case when the Euler angles of rotational motion are accordingly θi = ψi = π/2 and φi = π/2, i = 1, 2. It is found that three unstable collinear equilibrium points exist and two triangular such points which may be stable. Special attention has also been paid to the study of simple symmetric periodic orbits and 31 families consisting of such orbits have been determined. It has been found that only one of these families consists entirely of unstable members while the remaining families contain stable parts indicating that other families bifurcate from them. Finally, using the grid-search technique a global solution in the space of initial conditions is obtained which comprises simple and of higher multiplicities symmetric periodic orbits as well as escape and collision orbits.

  20. Triaxial shape with rotation around the longest principal axis in {sup 142}Gd

    SciTech Connect

    Carlsson, B. G.; Ragnarsson, I.; Bengtsson, R.; Lieder, E. O.; Lieder, R. M.; Pasternak, A. A.

    2008-09-15

    The cranking model is used to describe rotational bands. We investigate the approach of using diabatic configurations and minimizing the particle-number projected energy in a mesh of both {lambda},{delta} and deformation parameters. We use the method to interpret recent experimental data in {sup 142}Gd and conclude that for the highest spin states observed (I{approx_equal}30), the nucleus is triaxial and builds spin by rotating around the classically unfavored longest axis.

  1. Investigation of permeability anisotropy and polymodal fracture pattern development using a true-triaxial geophysical imaging cell

    NASA Astrophysics Data System (ADS)

    Nasseri, M. B.; Goodfellow, S. D.; Peterson, K.; Young, R.

    2013-12-01

    To increase our understanding of 3-D fluid transportation and development of polymodal fault patterns under 3-D strain a true-triaxial geophysical imaging cell is used. We present the effect of stress ratio σ2/σ3 =5 with the magnitudes of σ2 = 35 and σ3 =5 MPa on 3-D stress-strain behaviour, 3-D directional permeabilities and its anisotropy and 3-D fracture growth and propagation using acoustic emission techniques. An 8x8x8 cm3 Fontainebleau sandstone specimen was subjected to hydrostatic (σ1 = σ2 = σ3) and conventional triaxial (σ1> σ2 = σ3) stresses followed by differential loading under true-triaxial (σ1 >σ2 >σ3) stress states upto failure. 3-D closure of pore spaces and intergranular cracks affect the shear wave velocities more than compressional wave velocities along all three axes under any given mean stress for the specimen. VP, VS1 and VS2 measured along the σ3 direction show a decreasing trend beyond 125 MPa of axial stress due to the initiation and coalescence of micro-fracture propagation parallel/sub parallel to the σ1-σ2 plane. Combined analysis of drained directional permeability measurements, with VP/VS2 ratio obtained from each axis as a function of applied mean stress, shows that expulsion of water along the σ2 axis happens at a faster rate than the other two directions and VP/VS diminishes 15% along this direction. The σ2 direction is sub parallel to depositional layering within the specimen and is also characterized with the highest drop in normalized permeability (25%) and is categorized as the dry drained direction [O'Connel and Budiansky, 1977]. The σ1 direction has a lower permeability when compaction effects, along σ1 axis, disturbs the communication of water fluid between the pore spaces and cracks. The σ3 direction shows higher permeability than the other two directions indicating that pore spaces and cracks stay saturated and interconnected and is isobaric. Number of acoustic emission activity in the specimen tested

  2. DOES THE SAGITTARIUS STREAM CONSTRAIN THE MILKY WAY HALO TO BE TRIAXIAL?

    SciTech Connect

    Ibata, R.; Martin, N. F.; Lewis, G. F.; Bellazzini, M.; Correnti, M.

    2013-03-01

    Recent analyses of the stellar stream of the Sagittarius dwarf galaxy have suggested that the kinematics and three-dimensional location of the M-giant stars in this structure constrain the dark matter halo of our Galaxy to possess a triaxial shape that is extremely flattened, being essentially an oblate ellipsoid oriented perpendicular to the Galactic disk. Using a new stream-fitting algorithm, based on a Markov Chain Monte Carlo procedure, we investigate whether this claim remains valid if we allow the density profile of the Milky Way halo greater freedom. We find stream solutions that fit the leading and trailing arms of this structure even in a spherical halo, although this would need a rising Galactic rotation curve at large Galactocentric radius. However, the required rotation curve is not ruled out by current constraints. It appears therefore that for the Milky Way, halo triaxiality, despite its strong theoretical motivation, is not required to explain the Sagittarius stream. This degeneracy between triaxiality and the halo density profile suggests that, in future endeavors to model this structure, it will be advantageous to relax the strict analytic density profiles that have been used to date.

  3. Fully alternating, triaxial electric or magnetic fields offer new routes to fluid vorticity

    SciTech Connect

    Martin, James E.; Solis, Kyle J.

    2014-10-31

    Noncontact methods of generating strong fluid vorticity are important to problems involving heat and mass transfer, fluid mixing, active wetting, and droplet transport. Furthermore, because zero or even negative shear viscosities can be induced, vorticity can greatly extend the control range of the smart fluids used in magnetorheological devices. In recent work we have shown that a particular class of ac/ac/dc triaxial fields (so-called symmetry-breaking rational fields) can create strong vorticity in magnetic particle suspensions and have presented a theory of the vorticity that is based on the symmetry of the 2-d Lissajous trajectories of the field and its converse. In this paper we demonstrate that there are three countably infinite sets of fully alternating ac/ac/ac triaxial fields whose frequencies form rational triads that have the symmetry required to drive fluid vorticity. The symmetry of the 3-d Lissajous trajectories of the field and its converse can be derived and from this the direction of the vorticity axis can be predicted, as can the dependence of the sign of the vorticity on the phase relations between the three field components. Experimental results are presented that validate the symmetry theory. These discoveries significantly broaden the class of triaxial fields that can be exploited to produce strong noncontact flow.

  4. Fully alternating, triaxial electric or magnetic fields offer new routes to fluid vorticity

    DOE PAGESBeta

    Martin, James E.; Solis, Kyle J.

    2014-10-31

    Noncontact methods of generating strong fluid vorticity are important to problems involving heat and mass transfer, fluid mixing, active wetting, and droplet transport. Furthermore, because zero or even negative shear viscosities can be induced, vorticity can greatly extend the control range of the smart fluids used in magnetorheological devices. In recent work we have shown that a particular class of ac/ac/dc triaxial fields (so-called symmetry-breaking rational fields) can create strong vorticity in magnetic particle suspensions and have presented a theory of the vorticity that is based on the symmetry of the 2-d Lissajous trajectories of the field and its converse.more » In this paper we demonstrate that there are three countably infinite sets of fully alternating ac/ac/ac triaxial fields whose frequencies form rational triads that have the symmetry required to drive fluid vorticity. The symmetry of the 3-d Lissajous trajectories of the field and its converse can be derived and from this the direction of the vorticity axis can be predicted, as can the dependence of the sign of the vorticity on the phase relations between the three field components. Experimental results are presented that validate the symmetry theory. These discoveries significantly broaden the class of triaxial fields that can be exploited to produce strong noncontact flow.« less

  5. Full-Field Strain Methods for Investigating Failure Mechanisms in Triaxial Braided Composites

    NASA Technical Reports Server (NTRS)

    Littell, Justin D.; Binienda, Wieslaw K.; Goldberg, Robert K.; Roberts, Gary D.

    2008-01-01

    Recent advancements in braiding technology have led to commercially viable manufacturing approaches for making large structures with complex shape out of triaxial braided composite materials. In some cases, the static load capability of structures made using these materials has been higher than expected based on material strength properties measured using standard coupon tests. A more detailed investigation of deformation and failure processes in large-unit-cell-size triaxial braid composites is needed to evaluate the applicability of standard test methods for these materials and to develop alternative testing approaches. This report presents some new techniques that have been developed to investigate local deformation and failure using digital image correlation techniques. The methods were used to measure both local and global strains during standard straight-sided coupon tensile tests on composite materials made with 12- and 24-k yarns and a 0 /+60 /-60 triaxial braid architecture. Local deformation and failure within fiber bundles was observed and correlations were made between these local failures and global composite deformation and strength.

  6. What's up in the Milky Way? The orientation of the disc relative to the triaxial halo

    NASA Astrophysics Data System (ADS)

    Debattista, Victor P.; Roškar, Rok; Valluri, Monica; Quinn, Thomas; Moore, Ben; Wadsley, James

    2013-10-01

    Models of the Sagittarius stream have consistently found that the Milky Way disc is oriented such that its short axis is along the intermediate axis of the triaxial dark matter halo. We attempt to build models of disc galaxies in such an `intermediate-axis orientation'. We do this with three models. In the first two cases we simply rigidly grow a disc in a triaxial halo such that the disc ends up perpendicular to the global intermediate axis. We also attempt to coax a disc to form in an intermediate-axis orientation by producing a gas+dark matter triaxial system with gas angular momentum about the intermediate axis. In all cases we fail to produce systems which remain with stellar angular momentum aligned with the halo's intermediate axis, even when the disc's potential flattens the inner halo such that the disc is everywhere perpendicular to the halo's local minor axis. For one of these unstable simulations we show that the potential is even rounder than the models of the Milky Way potential in the region probed by the Sagittarius stream. We conclude that the Milky Way's disc is very unlikely to be in an intermediate-axis orientation. However we find that a disc can persist off one of the principal planes of the potential. We propose that the disc of the Milky Way must be tilted relative to the principal axes of the dark matter halo. Direct confirmation of this prediction would constitute a critical test of Modified Newtonian Dynamics.

  7. Errors induced in triaxial stress tensor calculations using incorrect lattice parameters

    SciTech Connect

    Ruud, C.O.; Kozaczek, K.J.

    1994-06-01

    A number of researchers have proposed that for some metallic alloys, an elaborate procedure is necessary in order to improve the accuracy of the measured triaxial stress tensor. Others have been concerned that the uncertainties in establishing the precise zero-stress lattice parameter of an alloyed and/or cold worked engineering metal could cause significantly more error than would result in ignoring the triaxial stress state and assuming the plane stress condition. This paper illustrates the effect of uncertainties in the zero-stress lattice parameters on the calculated triaxial stress state for zero stress powders of three common engineering alloys, i.e., 1010 steel, 304 stainless steel, and 2024 aluminum. Also, errors due to the incorrect lattice spacing in experimental stress analysis are presented for three examples, i.e., a silicon powder, 304 gainless steel cylinder and a diamond. For cases where the plane strain assumption is justified, the uncertainties due to the stress free lattice parameter can be reduced by a simple measurement.

  8. EVIDENCE FOR A TRIAXIAL MILKY WAY DARK MATTER HALO FROM THE SAGITTARIUS STELLAR TIDAL STREAM

    SciTech Connect

    Law, David R.; Majewski, Steven R.; Johnston, Kathryn V. E-mail: srm4n@virginia.ed

    2009-09-20

    Observations of the lengthy tidal streams produced by the destruction of the Sagittarius dwarf spheroidal (Sgr dSph) are capable of providing strong constraints on the shape of the Galactic gravitational potential. However, previous work, based on modeling different stream properties in axisymmetric Galactic models, has yielded conflicting results: while the angular precession of the Sgr leading arm is most consistent with a spherical or slightly oblate halo, the radial velocities of stars in this arm are reproduced only by prolate halo models. We demonstrate that this apparent paradox can be resolved by instead adopting a triaxial potential. Our new Galactic halo model, which simultaneously fits all well-established phase space constraints from the Sgr stream, provides the first conclusive evidence for, and tentative measurement of, triaxiality in an individual dark matter halo. The Milky Way halo within {approx}60 kpc is best characterized by a minor/major axis ratio of the isovelocity contours c/a {approx} 0.67, intermediate/major axis ratio b/a {approx} 0.83, and triaxiality parameter T {approx} 0.56. In this model, the minor axis of the dark halo is coincident with the Galactic X-axis connecting the Sun and the Galactic center to within {approx}15 deg., while the major axis also lies in the Galactic plane, approximately along the Galactic Y-axis.

  9. Evidence for a Triaxial Milky Way Dark Matter Halo from the Sagittarius Stellar Tidal Stream

    NASA Astrophysics Data System (ADS)

    Law, David R.; Majewski, Steven R.; Johnston, Kathryn V.

    2009-09-01

    Observations of the lengthy tidal streams produced by the destruction of the Sagittarius dwarf spheroidal (Sgr dSph) are capable of providing strong constraints on the shape of the Galactic gravitational potential. However, previous work, based on modeling different stream properties in axisymmetric Galactic models, has yielded conflicting results: while the angular precession of the Sgr leading arm is most consistent with a spherical or slightly oblate halo, the radial velocities of stars in this arm are reproduced only by prolate halo models. We demonstrate that this apparent paradox can be resolved by instead adopting a triaxial potential. Our new Galactic halo model, which simultaneously fits all well-established phase space constraints from the Sgr stream, provides the first conclusive evidence for, and tentative measurement of, triaxiality in an individual dark matter halo. The Milky Way halo within ~60 kpc is best characterized by a minor/major axis ratio of the isovelocity contours c/a ≈ 0.67, intermediate/major axis ratio b/a ≈ 0.83, and triaxiality parameter T ~ 0.56. In this model, the minor axis of the dark halo is coincident with the Galactic X-axis connecting the Sun and the Galactic center to within ~15°, while the major axis also lies in the Galactic plane, approximately along the Galactic Y-axis.

  10. A high performance sensor for triaxial cutting force measurement in turning.

    PubMed

    Zhao, You; Zhao, Yulong; Liang, Songbo; Zhou, Guanwu

    2015-01-01

    This paper presents a high performance triaxial cutting force sensor with excellent accuracy, favorable natural frequency and acceptable cross-interference for high speed turning process. Octagonal ring is selected as sensitive element of the designed sensor, which is drawn inspiration from ring theory. A novel structure of two mutual-perpendicular octagonal rings is proposed and three Wheatstone full bridge circuits are specially organized in order to obtain triaxial cutting force components and restrain cross-interference. Firstly, the newly developed sensor is tested in static calibration; test results indicate that the sensor possesses outstanding accuracy in the range of 0.38%-0.83%. Secondly, impacting modal tests are conducted to identify the natural frequencies of the sensor in triaxial directions (i.e., 1147 Hz, 1122 Hz and 2035 Hz), which implies that the devised sensor can be used for cutting force measurement in a high speed lathe when the spindle speed does not exceed 17,205 rev/min in continuous cutting condition. Finally, an application of the sensor in turning process is operated to show its performance for real-time cutting force measurement; the measured cutting forces demonstrate a good accordance with the variation of cutting parameters. Thus, the developed sensor possesses perfect properties and it gains great potential for real-time cutting force measurement in turning. PMID:25855035

  11. Fully alternating, triaxial electric or magnetic fields offer new routes to fluid vorticity.

    PubMed

    Martin, James E; Solis, Kyle J

    2015-01-14

    Noncontact methods of generating strong fluid vorticity are important to problems involving heat and mass transfer, fluid mixing, active wetting, and droplet transport. Furthermore, because zero or even negative shear viscosities can be induced, vorticity can greatly extend the control range of the smart fluids used in magnetorheological devices. In recent work we have shown that a particular class of ac/ac/dc triaxial fields (symmetry-breaking rational fields) can create strong vorticity in magnetic particle suspensions and have presented a theory of the vorticity that is based on the symmetry of the 2-d Lissajous trajectories of the field and its converse. In this paper we demonstrate that there are three countably infinite sets of fully alternating ac/ac/ac triaxial fields whose frequencies form rational triads that have the symmetry required to drive fluid vorticity. The symmetry of the 3-d Lissajous trajectories of the field and its converse can be derived and from this the direction of the vorticity axis can be predicted, as can the dependence of the sign of the vorticity on the phase relations between the three field components. Experimental results are presented that validate the symmetry theory. These discoveries significantly broaden the class of triaxial fields that can be exploited to produce strong noncontact flow. PMID:25358752

  12. A High Performance Sensor for Triaxial Cutting Force Measurement in Turning

    PubMed Central

    Zhao, You; Zhao, Yulong; Liang, Songbo; Zhou, Guanwu

    2015-01-01

    This paper presents a high performance triaxial cutting force sensor with excellent accuracy, favorable natural frequency and acceptable cross-interference for high speed turning process. Octagonal ring is selected as sensitive element of the designed sensor, which is drawn inspiration from ring theory. A novel structure of two mutual-perpendicular octagonal rings is proposed and three Wheatstone full bridge circuits are specially organized in order to obtain triaxial cutting force components and restrain cross-interference. Firstly, the newly developed sensor is tested in static calibration; test results indicate that the sensor possesses outstanding accuracy in the range of 0.38%–0.83%. Secondly, impacting modal tests are conducted to identify the natural frequencies of the sensor in triaxial directions (i.e., 1147 Hz, 1122 Hz and 2035 Hz), which implies that the devised sensor can be used for cutting force measurement in a high speed lathe when the spindle speed does not exceed 17,205 rev/min in continuous cutting condition. Finally, an application of the sensor in turning process is operated to show its performance for real-time cutting force measurement; the measured cutting forces demonstrate a good accordance with the variation of cutting parameters. Thus, the developed sensor possesses perfect properties and it gains great potential for real-time cutting force measurement in turning. PMID:25855035

  13. Effect of triaxial stress constraint on the deformation and fracture of polymers

    NASA Astrophysics Data System (ADS)

    Tiejun, Wang; Kishimoto, Kikno; Notomi, Mitsuo

    2002-10-01

    One purpose of this paper is to give a brief overview on the research status of deformation, fracture and toughening mechanisms of polymers, including experimental, theoretical and numerical studies. Emphasis is on the more recent progresses of micromechanics of rubber particle cavitation and crazing, and the development of fracture criteria for ductile polymers. The other purpose is to study the effect of triaxial stress constraint on the deformation and fracture behavior of polymers. Polycarbonate (PC), acrylonitrile-butadienestyrene (ABS) and PC/ABS alloy are considered in this investigation. A series of circumferentially blunt-notched bars are used to experimentally generate different triaxial stress fields. The fracture surfaces of specimens with different notch radius are examined by scanning electron microscope (SEM) to study the fracture and toughening mechanisms of polymer alloy. It is shown that the triaxial stress constraint has a significant effect on the deformation, fracture and toughening of PC, ABS and PC/ABS alloy. We will also discuss the extent to which a micromechanics criterion proposed by the first author can serve as a fracture criterion for ductile polymers. A new ductile fracture parameter is emphasized, which can be employed to evaluate the fracture ductility of polymers. Stress state independence of the parameter for the PC, ABS and PC/ABS alloy has been experimentally verified.

  14. High Voltage Testing of a 5-meter Prototype Triaxial HTS Cable

    SciTech Connect

    Sauers, Isidor; James, David Randy; Ellis, Alvin R; Tuncer, Enis; Pace, Marshall O; Gouge, Michael J; Demko, Jonathan A; Lindsay, David T

    2007-01-01

    High voltage tests were performed on a 5-m long prototype triaxial HTS cable (supplied by Ultera) at ORNL in preparation for installation of a 200-m HTS cable of the same design at the AEP utility substation in Columbus, Ohio. The triaxial design comprises three concentric phases and shield around a common former with the phase to phase dielectric at cryogenic temperature. Advantages of this design include increased current density, a reduced amount of HTS tape needed, and reduced heat load. The phase to phase voltage will be 13.2 kVrms (7.6 kVrms to ground). Preliminary testing was done on half-scale and full-scale terminations which successfully passed AC withstand, partial discharge, and impulse tests. High voltage tests conducted on the 5-m cable with the cable straight and after bending 90 degrees were ac withstand to 39 kVrms, partial discharge inception, and a minimum of 10 positive and 10 negative lightning waveform impulses at 110 kV. Phase to phase insulation was tested by applying high voltage to each phase one at a time with all the other phases grounded. Partial discharge data will be presented. The 5-m prototype triaxial HTS cable passed all the HV tests performed, with a PD inception voltage significantly above the required voltage.

  15. Experimental observation of dynamic ductile damage development under various triaxiality conditions

    NASA Astrophysics Data System (ADS)

    Pillon, Laurianne; Adolf, Lise-Marie

    2015-06-01

    Fracture in ductile materials finds its origin in microscopic mechanisms: the nucleation of voids that grow and coalesce in order to form a crack. The most popular of these models, proposed by Gurson, aims at describing the damage development with respect to the plastic behavior of porous material. The Gurson model has been extended by Perrin to describe damage evolution in ductile viscoplastic porous materials. The Gurson-Perrin model (GPm) allows representing damage development with respect to the stress triaxiality and strain-rate conditions. We propose a new experimental design able to test and validate the GPm under various dynamic conditions and for different triaxiality levels. The experimental project will be detailed. A notch is drawn in the Cu cylindrical target where damage develops and the local failure occurs. A variation of the notch radius enables a variation in the triaxiality level. Three notch radii have been tested. Observations with numerical cameras allow following the shape of the notch, a characteristic of damage development. Several PDV measurements have been performed around the target. A first analysis of this experimental process will be shown and comparisons with numerical simulations will be presented.

  16. The Effects of Stress Triaxiality, Temperature and Strain Rate on the Fracture Characteristics of a Nickel-Base Superalloy

    NASA Astrophysics Data System (ADS)

    Wang, Jianjun; Guo, Weiguo; Guo, Jin; Wang, Ziang; Lu, Shengli

    2016-05-01

    In this work, to study the effects of stress triaxiality, temperature, and strain rate on the fracture behaviors of a single-crystal Nickel-base superalloy, a series of experiments over a temperature range of 293 to 1373 K, strain rate range of 0.001 to 4000/s, and stress triaxiality range of -0.6 to 1.1 are conducted. Anomalous peak of stress is noticed in the yield stress versus temperature curves, and strain rate effect on the anomalous peak of yield stress is analyzed. The anomalous peak shifts to higher temperature as the strain rate increases. Then the effects of stress triaxiality, temperature, and strain rate on its fracture behaviors, including strain to fracture, path of crack propagation, and fracture surface, are observed and analyzed. A valley of the fracture strain is formed in the fracture strain versus temperature curve over the selected temperature range. The micrograph of fracture surface is largely dependent on the temperature, stress triaxiality, and strain rate. Finally, the original Johnson-Cook (J-C) fracture criterion cannot describe the effect of stress triaxiality and temperature on the fracture behaviors of single-crystal Nickel-base superalloy. A modified J-C fracture criterion is developed, which takes the anomalous stress triaxiality and temperature effects on the fracture behaviors of single-crystal Nickel-base superalloy into account.

  17. Study on the Particle Size Distribution Nano-Particles of Mining Minerals on Whiteness of Triaxial Body

    NASA Astrophysics Data System (ADS)

    Mathur, Ravi; Soni, Aditi

    White wares produced worldwide represent the foundation of much of the ceramic industry; Porcelain bodies fabricated from triaxial mixtures of clay, quartz and feldspar with different size and amounts of nano particles were investigated. Although the purity of raw materials has a strong effect on the colour of the fired bodies, the particle size of raw materials also effect the whiteness The raw material mining minerals china Clay, Feldspar, quarts were prepared of various sized nano particles contains 10.60 -20.22%, 56.84- 70.80 % and 34.87-50.76 % of 100nm respectively. The fired bodies of raw mining minerals and triaxial bodies were subjected to colour measurement. The differences in whiteness were compared and discussed. The studies so far carried out is upto 400 mesh size while the present study has included up to 100nm particle size. A statistical correlation between whiteness of feldspar and triaxial body was also carried out. The correlation between china clay and triaxial body are 0.53, 0.57 and 0.66 for china clay similarly correlation for feldspar is 0.49, 0.73 and 0.83 for triaxial body it are 0.97, 0.84 and 0.75 for A1, A2 and A3 samples. Correlation between china clay and feldspar with triaxial body are 0.79 and 0.92 respectively.

  18. Semantic description of drama scene by using SD-form

    NASA Astrophysics Data System (ADS)

    Niimi, Michiharu; Kawaguchi, Eiji

    1997-01-01

    Multimedia data processing is becoming more and more a central concern among the people who have been working on image processing. Multimedia database retrieval is one of such a problem. A foreign language study assisting system is a good example for a multimedia data base design. Because each language depends on conversational situation such as topic and speech intention as well as place of conversation.In that case, we can not neglect the semantic aspect of multimedia information. The author's group has already proposed a semantic structure description form, called the SD-form, of the language meaning. They studied the feasibility of its application to natural language generation, story understanding, and conversational text retrieval systems. This paper presents our new attempt to expand our previous system from a text database systems to a multimedia database system which include motion picture, speech sound as well as language text. the source of the data in this project is a series of bilingual TV drama broadcasted in Japan. The most important point is this attempt is that each video scene is described by a set of SD-forms by which scenes are retrieved semantically.

  19. FUSE Observations of He-rich sdB Stars

    NASA Technical Reports Server (NTRS)

    Swiegart, A. V.; Lanz, T.; Brown, T. M.; Hubeny, I.; Landsman, W. B.

    2003-01-01

    Most subdwarf B stars are extremely deficient in helium and selected light elements, but a minority are helium-rich. New evolutionary calculations suggest that these helium-rich sdB stars are the result of a delayed helium-core flash on the white dwarf cooling curve, which leads to extensive mixing between the hydrogen envelope and helium core. Such mixed stars should show greatly enhanced helium and carbon with respect to the other heavy elements. We have recently obtained FUSE spectra of two helium-rich sdB stars, PG1544+488 and JL87, revealing huge C Ill lines at 977 and 1176 A. Our analysis shows that PG1544+488 has a surface composition of 97% He, 2% C, and 1% N, in agreement with the new evolutionary scenario. While JL87 also reveals a large enrichment in carbon and nitrogen (1.4% and 0.4%, respectively), there is still a significant amount of hydrogen in its atmosphere.

  20. Digital LAMP in a sample self-digitization (SD) chip

    PubMed Central

    Herrick, Alison M.; Dimov, Ivan K.; Lee, Luke P.; Chiu, Daniel T.

    2012-01-01

    This paper describes the realization of digital loop-mediated DNA amplification (dLAMP) in a sample self-digitization (SD) chip. Digital DNA amplification has become an attractive technique to quantify absolute concentrations of DNA in a sample. While digital polymerase chain reaction is still the most widespread implementation, its use in resource—limited settings is impeded by the need for thermal cycling and robust temperature control. In such situations, isothermal protocols that can amplify DNA or RNA without thermal cycling are of great interest. Here, we showed the successful amplification of single DNA molecules in a stationary droplet array using isothermal digital loop-mediated DNA amplification. Unlike most (if not all) existing methods for sample discretization, our design allows for automated, loss-less digitization of sample volumes on-chip. We demonstrated accurate quantification of relative and absolute DNA concentrations with sample volumes of less than 2 μl. We assessed the homogeneity of droplet size during sample self-digitization in our device, and verified that the size variation was small enough such that straightforward counting of LAMP-active droplets sufficed for data analysis. We anticipate that the simplicity and robustness of our SD chip make it attractive as an inexpensive and easy-to-operate device for DNA amplification, for example in point-of-care settings. PMID:22399016

  1. Modeling of Failure for Analysis of Triaxial Braided Carbon Fiber Composites

    NASA Technical Reports Server (NTRS)

    Goldberg, Robert K.; Littell, Justin D.; Binienda, Wieslaw K.

    2010-01-01

    In the development of advanced aircraft-engine fan cases and containment systems, composite materials are beginning to be used due to their low weight and high strength. The design of these structures must include the capability of withstanding impact loads from a released fan blade. Relatively complex triaxially braided fiber architectures have been found to yield the best performance for the fan cases. To properly work with and design these structures, robust analytical tools are required that can be used in the design process. A new analytical approach models triaxially braided carbon fiber composite materials within the environment of a transient dynamic finite-element code, specifically the commercially available transient dynamic finite-element code LS-DYNA. The geometry of the braided composites is approximated by a series of parallel laminated composites. The composite is modeled by using shell finite elements. The material property data are computed by examining test data from static tests on braided composites, where optical strain measurement techniques are used to examine the local strain variations within the material. These local strain data from the braided composite tests are used along with a judicious application of composite micromechanics- based methods to compute the stiffness properties of an equivalent unidirectional laminated composite required for the shell elements. The local strain data from the braided composite tests are also applied to back out strength and failure properties of the equivalent unidirectional composite. The properties utilized are geared towards the application of a continuum damage mechanics-based composite constitutive model available within LS-DYNA. The developed model can be applied to conduct impact simulations of structures composed of triaxially braided composites. The advantage of this technology is that it facilitates the analysis of the deformation and damage response of a triaxially braided polymer matrix

  2. An automated framework for 3D serous pigment epithelium detachment segmentation in SD-OCT images

    PubMed Central

    Sun, Zhuli; Chen, Haoyu; Shi, Fei; Wang, Lirong; Zhu, Weifang; Xiang, Dehui; Yan, Chenglin; Li, Liang; Chen, Xinjian

    2016-01-01

    Pigment epithelium detachment (PED) is an important clinical manifestation of multiple chorioretinal diseases, which can cause loss of central vision. In this paper, an automated framework is proposed to segment serous PED in SD-OCT images. The proposed framework consists of four main steps: first, a multi-scale graph search method is applied to segment abnormal retinal layers; second, an effective AdaBoost method is applied to refine the initial segmented regions based on 62 extracted features; third, a shape-constrained graph cut method is applied to segment serous PED, in which the foreground and background seeds are obtained automatically; finally, an adaptive structure elements based morphology method is applied to remove false positive segmented regions. The proposed framework was tested on 25 SD-OCT volumes from 25 patients diagnosed with serous PED. The average true positive volume fraction (TPVF), false positive volume fraction (FPVF), dice similarity coefficient (DSC) and positive predictive value (PPV) are 90.08%, 0.22%, 91.20% and 92.62%, respectively. The proposed framework can provide clinicians with accurate quantitative information, including shape, size and position of the PED region, which can assist clinical diagnosis and treatment. PMID:26899236

  3. Open sd-shell nuclei from first principles

    DOE PAGESBeta

    Jansen, Gustav R.; Signoracci, Angelo J.; Hagen, Gaute; Navratil, Petr

    2016-07-05

    We extend the ab initio coupled-cluster e ective interaction (CCEI) method to open-shell nuclei with protons and neutrons in the valence space, and compute binding energies and excited states of isotopes of neon and magnesium. We employ a nucleon-nucleon and three-nucleon interaction from chiral e ective eld theory evolved to a lower cuto via a similarity renormalization group transformation. We nd good agreement with experiment for binding energies and spectra, while charge radii of neon isotopes are underestimated. For the deformed nuclei 20Ne and 24Mg we reproduce rotational bands and electric quadrupole transitions within uncertainties estimated from an e ectivemore » eld theory for deformed nuclei, thereby demonstrating that collective phenomena in sd-shell nuclei emerge from complex ab initio calculations.« less

  4. Charge radii of neon isotopes across the sd neutron shell

    SciTech Connect

    Marinova, K.; Geithner, W.; Kappertz, S.; Kloos, S.; Kotrotsios, G.; Neugart, R.; Wilbert, S.; Kowalska, M.; Keim, M.; Blaum, K.; Lievens, P.; Simon, H.

    2011-09-15

    We report on the changes in mean square charge radii of unstable neon nuclei relative to the stable {sup 20}Ne, based on the measurement of optical isotope shifts. The studies were carried out using collinear laser spectroscopy on a fast beam of neutral neon atoms. High sensitivity on short-lived isotopes was achieved thanks to nonoptical detection based on optical pumping and state-selective collisional ionization, which was complemented by an accurate determination of the beam kinetic energy. The new results provide information on the structural changes in the sequence of neon isotopes all across the neutron sd shell, ranging from the proton drip line nucleus and halo candidate {sup 17}Ne up to the neutron-rich {sup 28}Ne in the vicinity of the ''island of inversion.'' Within this range the charge radius is smallest for {sup 24}Ne with N=14 corresponding to the closure of the neutron d{sub 5/2} shell, while it increases toward both neutron shell closures, N=8 and N=20. The general trend of the charge radii correlates well with the deformation effects which are known to be large for several neon isotopes. In the neutron-deficient isotopes, structural changes arise from the onset of proton-halo formation for {sup 17}Ne, shell closure in {sup 18}Ne, and clustering effects in {sup 20,21}Ne. On the neutron-rich side the transition to the island of inversion plays an important role, with the radii in the upper part of the sd shell confirming the weakening of the N=20 magic number. The results add new information to the radii systematics of light nuclei where data are scarce because of the small contribution of nuclear-size effects to the isotope shifts which are dominated by the finite-mass effect.

  5. A Unified Framework for the Orbital Structure of Bars and Triaxial Ellipsoids

    NASA Astrophysics Data System (ADS)

    Valluri, Monica; Shen, Juntai; Abbott, Caleb; Debattista, Victor P.

    2016-02-01

    We examine a large random sample of orbits in two self-consistent simulations of N-body bars. Orbits in these bars are classified both visually and with a new automated orbit classification method based on frequency analysis. The well-known prograde x1 orbit family originates from the same parent orbit as the box orbits in stationary and rotating triaxial ellipsoids. However, only a small fraction of bar orbits (∼4%) have predominately prograde motion like their periodic parent orbit. Most bar orbits arising from the x1 orbit have little net angular momentum in the bar frame, making them equivalent to box orbits in rotating triaxial potentials. In these simulations a small fraction of bar orbits (∼7%) are long-axis tubes that behave exactly like those in triaxial ellipsoids: they are tipped about the intermediate axis owing to the Coriolis force, with the sense of tipping determined by the sign of their angular momentum about the long axis. No orbits parented by prograde periodic x2 orbits are found in the pure bar model, but a tiny population (∼2%) of short-axis tube orbits parented by retrograde x4 orbits are found. When a central point mass representing a supermassive black hole (SMBH) is grown adiabatically at the center of the bar, those orbits that lie in the immediate vicinity of the SMBH are transformed into precessing Keplerian orbits that belong to the same major families (short-axis tubes, long-axis tubes and boxes) occupying the bar at larger radii. During the growth of an SMBH, the inflow of mass and outward transport of angular momentum transform some x1 and long-axis tube orbits into prograde short-axis tubes. This study has important implications for future attempts to constrain the masses of SMBHs in barred galaxies using orbit-based methods like the Schwarzschild orbit superposition scheme and for understanding the observed features in barred galaxies.

  6. Influence of dynamical equatorial flattening and orientation of a triaxial core on prograde diurnal polar motion

    NASA Astrophysics Data System (ADS)

    Sun, Rong; Shen, WenBin

    2016-04-01

    The noise floor of empirical models of diurnal Earth Rotation could reach as low as 1μas as shown by several recent studies. In another aspect, the differences between these empirical models with the theoretical model predictions given by IERS Convention (2010) for certain diurnal frequencies are more than 10 μas (e.g. K1). The traxiality of the core is ignored in the theoretical model given by IERS Convention (2010) because it is highly uncertain. To explain the difference between the empirical model and theoretical model, we consider the possible influence of a triaxial core. We use the difference between empirical models and theoretical model predictions given by IERS Convention (2010) as input to invert the traxiality parameter of the core. In the inversion, we assume the ocean tide response obeys the admittance theory. So extra six admittance parameters are introduced to model the difference between smooth responses inferred from empirical models and that given by theoretical model predictions from IERS Convention (2010). The results show that adding core triaxiality into the theoretical model could narrow the difference between empirical model and theoretical model at diurnal frequencies. The residual of amplitude becomes smaller. For a set of tide components consisting of seven diurnal frequencies (Q1, O1, M1, P1, K1, J1, Oo1), the root mean square of the residual of this set have decreased from more than 10μas to 2˜3μas for most of the empirical models. As for the dynamical equatorial flattening of the core, estimates inverted based on different empirical models are consistent within standard deviation. The results also suggest that the principal axes of the triaxial core does not coincidence with the principal axes of the whole Earth. This study is supported by National 973 Project China (grant No. 2013CB733305), NSFC (grant Nos. 41174011, 41210006, 41504019).

  7. Fatigue Behavior of Granite Subjected to Cyclic Loading Under Triaxial Compression Condition

    NASA Astrophysics Data System (ADS)

    Wang, Zhechao; Li, Shucai; Qiao, Liping; Zhao, Jiangang

    2013-11-01

    A series of laboratory tests were performed to examine the fatigue behavior of granite subjected to cyclic loading under triaxial compression condition. In these tests, the influences of volumetric change and residual strain on the deformation modulus of granite under triaxial cyclic compression were investigated. It is shown that the fatigue behavior of granite varies with the tendency for volumetric change in triaxial cyclic compression tests. In the stress-strain space, there are three domains for fatigue behavior of rock subjected to cyclic loading, namely the volumetric compaction, volumetric dilation with strain-hardening behavior, and volumetric dilation with strain-softening behavior domains. In the different domains, the microscopic mechanisms for rock deformation are different. It was also found that the stress level corresponding to the transition from volumetric compaction to volumetric dilation could be considered as the threshold for fatigue failure. The potential of fatigue deformation was compared with that of plastic deformation. The comparison shows that rocks exhibit higher resistances to volumetric deformation under cyclic loading than under plastic loading. The influence of residual strain on the fatigue behavior of rock was also investigated. It was found that the axial residual strain could be a better option to describe the fatigue behavior of rock than the loading cycle number. A constitutive model for the fatigue behavior of rock subjected to cyclic loading is proposed according to the test results and discussion. In the model, the axial residual strain is considered as an internal state variable. The influences of confining pressure and peak deviatoric stress on the deformation modulus are considered in a term named the equivalent stress. Comparison of test results with model predictions shows that the proposed model is capable of describing the prepeak fatigue behavior of rock subjected to cyclic loading.

  8. Are Stellar Over-Densities in Dwarf Galaxies the ``Smoking Gun'' of Triaxial Dark Matter Haloes?

    NASA Astrophysics Data System (ADS)

    Peñarrubia, Jorge; Walker, Matthew G.; Gilmore, Gerard

    2010-06-01

    We use N-body simulations to study the tidal evolution of globular clusters (GCs) in dwarf spheroidal (dSph) galaxies. Our models adopt a cosmologically motivated scenario in which the dSph is approximated by a static NFW halo with a triaxial shape. For a large set of orbits and projection angles we examine the spatial and velocity distribution of stellar debris deposited during the complete disruption of stellar clusters. Our simulations show that such debris appears as shells, isolated clumps and elongated over-densities at low surface brightness (>=26 mag/arcsec2), reminiscent of substructure observed in several MW dSphs. Such features arise from the triaxiality of the galaxy potential and do not dissolve in time. Stellar over-densities reported in several MW dSphs may thus be the telltale evidence of dark matter haloes being triaxial in shape. We explore a number of kinematical signatures that would help to validate (or falsify) this scenario. The mean angular momentum of the cluster debris associated with box and resonant orbits, which are absent in spherical potentials, is null. As a result, we show that the line-of-sight velocity distribution may exhibit a characteristic ``double-peak'' depending on the oriention of the viewing angle with respect to the progenitor's orbital plane. Kinematic surveys of dSphs may help to detect and identify substructures associated with the disruption of stellar clusters, as well as to address the shape of the dark matter haloes in which dSphs are embedded.

  9. Level set discrete element method for three-dimensional computations with triaxial case study

    NASA Astrophysics Data System (ADS)

    Kawamoto, Reid; Andò, Edward; Viggiani, Gioacchino; Andrade, José E.

    2016-06-01

    In this paper, we outline the level set discrete element method (LS-DEM) which is a discrete element method variant able to simulate systems of particles with arbitrary shape using level set functions as a geometric basis. This unique formulation allows seamless interfacing with level set-based characterization methods as well as computational ease in contact calculations. We then apply LS-DEM to simulate two virtual triaxial specimens generated from XRCT images of experiments and demonstrate LS-DEM's ability to quantitatively capture and predict stress-strain and volume-strain behavior observed in the experiments.

  10. Selection rules for electromagnetic transitions in triaxially deformed odd-A nuclei

    SciTech Connect

    Tanabe, Kosai; Sugawara-Tanabe, Kazuko

    2008-06-15

    The approximate selection rules for the interband and intraband electromagnetic transitions are predicted referring to two quantum numbers, which are derived from an algebraic solution for the particle-rotor model with one high-j nucleon coupled to a triaxially deformed core. It is shown that the inclusion of angular momentum dependence for moments of inertia reproduces the experimental excitation energies relative to a reference quite well both for positive and negative parity TSD bands in {sup 161,163,165,167}Lu.

  11. Grain-based characterisation and acoustic wave propagation in a sand packing subject to triaxial compression

    NASA Astrophysics Data System (ADS)

    Saadatfar, Mohammad; Francois, Nicolas; Arad, Alon; Madadi, Mahyar; Sheppard, Adrian; Senden, Tim; Knackstedt, Mark

    2013-06-01

    This paper presents a study of 3D deformation process in a dry packing of Ottawa sand. X-ray microtomography is used to acquire scans of a triaxial test of the sample at five axial stress levels. Using 3D image analysis we are able to resolve particle scale features. Particle tracking combined with finite element simulations reveal that the rotational transformation of particles is one of the primary mechanisms of elastic energy dissipation at the grain scale. By analysing grain contact orientation, we show that stress induced anisotropy is spatially correlated to the compressional elastic wave.

  12. Miniature triaxial metastable ionization detector for gas chromatographic trace analysis of extraterrestrial volatiles

    NASA Technical Reports Server (NTRS)

    Woeller, F. H.; Kojiro, D. R.; Carle, G. C.

    1984-01-01

    The present investigation is concerned with a miniature metastable ionization detector featuring an unconventional electrode configuration, whose performance characteristics parallel those of traditional design. The ionization detector is to be incorporated in a flight gas chromatograph (GC) for use in the Space Shuttle. The design of the detector is discussed, taking into account studies which verified the sensitivity of the detector. The triaxial design of the detector is compared with a flat-plate style. The obtained results show that the principal goal of developing a miniature, highly sensitive ionization detector for flight applications was achieved. Improved fabrication techniques will utilize glass-to-metal seals and brazing procedures.

  13. A low-power fall detection algorithm based on triaxial acceleration and barometric pressure.

    PubMed

    Wang, Changhong; Narayanan, Michael R; Lord, Stephen R; Redmond, Stephen J; Lovell, Nigel H

    2014-01-01

    This paper proposes a low-power fall detection algorithm based on triaxial accelerometry and barometric pressure signals. The algorithm dynamically adjusts the sampling rate of an accelerometer and manages data transmission between sensors and a controller to reduce power consumption. The results of simulation show that the sensitivity and specificity of the proposed fall detection algorithm are both above 96% when applied to a previously collected dataset comprising 20 young actors performing a combination of simulated falls and activities of daily living. This level of performance can be achieved despite a 10.9% reduction in power consumption. PMID:25570023

  14. Improved Hybrid Genome Assemblies of Two Strains of Bacteroides xylanisolvens, SD_CC_1b and SD_CC_2a, Obtained Using Illumina and 454 Sequencing Technologies

    PubMed Central

    Ramaraj, Thiruvarangan; Sundararajan, Anitha; Schilkey, Faye D.; DelVecchio, Vito G.; Donlon, Mildred; Ziemer, Cherie

    2014-01-01

    Bacteroides xlyanisolvens strains (SD_CC_1b, SD_CC_2a) isolated from human feces were grown on crystalline cellulose. Cellulolytic properties are not common in Bacteroides species. Here, we report improved genome sequences of both of the B. xlyanisolvens strains. PMID:24699955

  15. Improved hybrid genome assemblies of 2 strains of Bacteroides xylanisolvens SD-CC-1b and SD-CC-2a using Illumina and 454 sequencing technologies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacteroides xlyanisolvens strains (SD_CC_1b, SD_CC_2a) isolated from human feces were able to grow on crystalline cellulose. Cellulolytic properties are not common in Bacteroides species. Here, we report improved genome sequences of both the B. xlyanisolvens strains....

  16. An improved suppression method of the transverse-electromagnetic mode leakage with two reflectors in the triaxial klystron amplifier

    SciTech Connect

    Qi, Zumin; Zhang, Jun; Zhong, Huihuang; Zhang, Qiang; Zhu, Danni

    2014-07-15

    Suppression of the transverse-electromagnetic (TEM) mode leakage is crucial in the design of a triaxial klystron amplifier with high gain, because a small microwave leakage from the buncher or the output cavity could overwhelm the input signal with low power. In this paper, a specially designed reflector is proposed to suppress the TEM mode leakage, whose axial electric field is approximately zero at the beam radial position. Theoretical analysis indicates that the reflector introduces little influence on the normal modulation of the beam while keeping a high reflection coefficient. By using two such reflectors with different eigen frequencies located in front of the buncher cavity and the output cavity, respectively, an improved triaxial klystron amplifier is presented. The simulation results show that the reflectors substantially decrease the TEM mode leakage power and achieve very good isolation among the cavities. The improved triaxial klystron amplifier can operate normally with 10's kW microwave injection without self-oscillations.

  17. An improved suppression method of the transverse-electromagnetic mode leakage with two reflectors in the triaxial klystron amplifier

    NASA Astrophysics Data System (ADS)

    Qi, Zumin; Zhang, Jun; Zhong, Huihuang; Zhang, Qiang; Zhu, Danni

    2014-07-01

    Suppression of the transverse-electromagnetic (TEM) mode leakage is crucial in the design of a triaxial klystron amplifier with high gain, because a small microwave leakage from the buncher or the output cavity could overwhelm the input signal with low power. In this paper, a specially designed reflector is proposed to suppress the TEM mode leakage, whose axial electric field is approximately zero at the beam radial position. Theoretical analysis indicates that the reflector introduces little influence on the normal modulation of the beam while keeping a high reflection coefficient. By using two such reflectors with different eigen frequencies located in front of the buncher cavity and the output cavity, respectively, an improved triaxial klystron amplifier is presented. The simulation results show that the reflectors substantially decrease the TEM mode leakage power and achieve very good isolation among the cavities. The improved triaxial klystron amplifier can operate normally with 10's kW microwave injection without self-oscillations.

  18. Application of the triaxial quadrupole-octupole rotor to the ground and negative-parity levels of actinide nuclei

    NASA Astrophysics Data System (ADS)

    Nadirbekov, M. S.; Minkov, N.; Strecker, M.; Scheid, W.

    2016-03-01

    In this work, we examine the possibility to describe yrast positive- and negative-parity excitations of deformed even-even nuclei through a collective rotation model in which the nuclear surface is characterized by triaxial quadrupole and octupole deformations. The nuclear moments of inertia are expressed as sums of quadrupole and octupole parts. By assuming an adiabatic separation of rotation and vibration degrees of freedom, we suppose that the structure of the positive- and negative-parity bands may be determined by the triaxial-rigid-rotor motion of the nucleus. By diagonalizing the Hamiltonian in a symmetrized rotor basis with embedded parity, we obtain a model description for the yrast positive- and negative-parity bands in several actinide nuclei. We show that the energy displacement between the opposite-parity sequences can be explained as the result of the quadrupole-octupole triaxiality.

  19. Combined triaxial accelerometry and heart rate telemetry for the physiological characterization of Latin dance in non-professional adults.

    PubMed

    Domene, Pablo A; Easton, Chris

    2014-03-01

    The purpose of this study was to value calibrate, cross-validate, and determine the reliability of a combined triaxial accelerometry and heart rate telemetry technique for characterizing the physiological and physical activity parameters of Latin dance. Twenty-two non-professional adult Latin dancers attended two laboratory-based dance trials each. After familiarization and a standardized warm-up, a multi-stage (3 x 5-minute) incremental (based on song tempo) Afro-Cuban salsa choreography was performed while following a video displayed on a projection screen. Data were collected with a portable indirect calorimeter, a heart rate telemeter, and wrist-, hip-, and ankle-mounted ActiGraph GT3X+ accelerometers. Prediction equations for energy expenditure and step count were value calibrated using forced entry multiple regression and cross-validated using a delete-one jackknife approach with additional Bland-Altman analysis. The average dance intensity reached 6.09 ± 0.96 kcal/kg/h and demanded 45.9 ± 11.3% of the heart rate reserve. Predictive ability of the derived models was satisfactory, where R(2) = 0.80; SEE = 0.44 kcal/kg/h and R(2) = 0.74; SEE = 3 step/min for energy expenditure and step count, respectively. Dependent t-tests indicated no differences between predicted and measured values for both energy expenditure (t65 = -0.25, p = 0.80) and step count (t65 = -0.89, p = 0.38). The 95% limits of agreement for energy expenditure and step count were -0.98 to 0.95 kcal/kg/h and -7 to 7 step/min, respectively. Latin dance to salsa music elicits physiological responses representative of moderate to vigorous physical activity, and a wrist-worn accelerometer with simultaneous heart rate measurement constitutes a valid and reliable technique for the prediction of energy expenditure and step count during Latin dance. PMID:24568801

  20. Triaxial Fabrics

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Gentax Corporation's triaxal fabrics are woven from three separate yarn sets whose intersections form equilateral triangles. This type of weave, derived from space shuttle pressure suits, assures practically equal strength in every direction; has essentially no bias, or weak dimension offering greater resistance to tear and shear along with significant weight reduction. Applications of the Triax line include inflatable equipment, life vests, aircraft evacuation slides, helicopter flotation devices, tension structures, safety clothing and sailcloth for boats. Ability to accept compound curvatures with no distortion of the weave configuration makes it useful in manufacturing molded composites.

  1. Triaxial shapes in the ground states of even-even neutron-rich Ru isotopes

    SciTech Connect

    Ahmad, I.; Lister, C.J.; Morss, L.R.

    1995-08-01

    Partial level schemes for {sup 108,110,112}Ru, and {sup 114}Ru about which nothing was previously known, were determined from the measurement of prompt, triple-gamma coincidences in {sup 248}Cm fission fragments. A 5-mg {sup 249}Cm source, mixed with 65-mg KCl and pressed in the form of a 7-mm diameter pellet, was used for the experiment. Prompt {gamma} rays emitted from the fission fragments were detected with the Eurogam array at Daresbury, which at that time consisted of 45 Compton suppressed Ge detectors and 5 LEPS spectrometers. Transitions in Ru were identified by gating on {gamma} rays in the complementary Te fragments. Figure I-25 shows the technique used to identify the previously unknown transitions in {sup 114}Ru and its partial level scheme. High spin states up to spin 10 h were observed and the {gamma}-ray branching ratios were determined. The ratios of electric quadrupole transition probabilities deduced from the experimental branching ratios were found to be in good agreement with the predictions of a simple model of rigid triaxial rotor. Our analysis shows that gamma deformation in Ru isotopes is increasing with the neutron number and the gamma value for {sup 112}Ru and {sup 114}Ru is {approximately} 25 degrees. This is one of the highest gamma values encountered in nuclei, suggesting soft triaxial shapes for {sup 112}Ru and {sup 114}Ru. The results of this investigation were published.

  2. Experimental and Numerical Analysis of Triaxially Braided Composites Utilizing a Modified Subcell Modeling Approach

    NASA Technical Reports Server (NTRS)

    Cater, Christopher; Xiao, Xinran; Goldberg, Robert K.; Kohlman, Lee W.

    2015-01-01

    A combined experimental and analytical approach was performed for characterizing and modeling triaxially braided composites with a modified subcell modeling strategy. Tensile coupon tests were conducted on a [0deg/60deg/-60deg] braided composite at angles [0deg, 30deg, 45deg, 60deg and 90deg] relative to the axial tow of the braid. It was found that measured coupon strength varied significantly with the angle of the applied load and each coupon direction exhibited unique final failures. The subcell modeling approach implemented into the finite element software LS-DYNA was used to simulate the various tensile coupon test angles. The modeling approach was successful in predicting both the coupon strength and reported failure mode for the 0deg, 30deg and 60deg loading directions. The model over-predicted the strength in the 90deg direction; however, the experimental results show a strong influence of free edge effects on damage initiation and failure. In the absence of these local free edge effects, the subcell modeling approach showed promise as a viable and computationally efficient analysis tool for triaxially braided composite structures. Future work will focus on validation of the approach for predicting the impact response of the braided composite against flat panel impact tests.

  3. Experimental and Numerical Analysis of Triaxially Braided Composites Utilizing a Modified Subcell Modeling Approach

    NASA Technical Reports Server (NTRS)

    Cater, Christopher; Xiao, Xinran; Goldberg, Robert K.; Kohlman, Lee W.

    2015-01-01

    A combined experimental and analytical approach was performed for characterizing and modeling triaxially braided composites with a modified subcell modeling strategy. Tensile coupon tests were conducted on a [0deg/60deg/-60deg] braided composite at angles of 0deg, 30deg, 45deg, 60deg and 90deg relative to the axial tow of the braid. It was found that measured coupon strength varied significantly with the angle of the applied load and each coupon direction exhibited unique final failures. The subcell modeling approach implemented into the finite element software LS-DYNA was used to simulate the various tensile coupon test angles. The modeling approach was successful in predicting both the coupon strength and reported failure mode for the 0deg, 30deg and 60deg loading directions. The model over-predicted the strength in the 90deg direction; however, the experimental results show a strong influence of free edge effects on damage initiation and failure. In the absence of these local free edge effects, the subcell modeling approach showed promise as a viable and computationally efficient analysis tool for triaxially braided composite structures. Future work will focus on validation of the approach for predicting the impact response of the braided composite against flat panel impact tests.

  4. Effective detection method for falls according to the distance between two tri-axial accelerometers

    NASA Astrophysics Data System (ADS)

    Kim, Jae-Hyung; Park, Geun-Chul; Kim, Soo-Hong; Kim, Soo-Sung; Lee, Hae-Rim; Jeon, Gye-Rok

    2016-04-01

    Falls and fall-related injuries are a significant problem in the elderly population. A number of different approaches for detecting falls and activities of daily living (ADLs) have been conducted in recent years. However, distinguishing between real falls and certain fall-like ADL is often difficult. The aim of this study is to discriminate falls from fall-like ADLs such as jogging, jumping, and jumping down. The distance between two tri-axial accelerometers attached to the abdomen and the sternum was increased from 10 to 30 cm in 10-cm intervals. Experiments for falls and ADLs were performed to investigate the feasibility of the detection system for falls developed in this study. When the distances between the two tri-axial electrometers were 20 and 30 cm, fall-like ADLs were effectively distinguished from falls. The thresholds for three parameters — SVM, Diff Z, and Sum_diff_Z — were set; falls could be distinguished from ADL action sequences when the SVM value was larger than 4 g (TH1), the Diff_Z parameter was larger than 1.25 g (TH2), and the Sum_diff_Z parameter was larger than 15 m/s (TH3). In particular, when the SVM, Diff_Z, and Sum_diff_Z parameter were sequentially applied to thresholds (TH1, TH2, and TH3), fall-like ADL action sequences were accurately discriminated from falls.

  5. Tension Strength, Failure Prediction and Damage Mechanisms in 2D Triaxial Braided Composites with Notch

    NASA Technical Reports Server (NTRS)

    Norman, Timothy L.; Anglin, Colin

    1995-01-01

    The unnotched and notched (open hole) tensile strength and failure mechanisms of two-dimensional (2D) triaxial braided composites were examined. The effect of notch size and notch position were investigated. Damage initiation and propagation in notched and unnotched coupons were also examined. Theory developed to predict the normal stress distribution near an open hole and failure for tape laminated composites was evaluated for its applicability to 2D triaxial braided textile composite materials. Four different fiber architectures were considered; braid angle, yarn and braider size, percentage of longitudinal yarns and braider angle varied. Tape laminates equivalent to textile composites were also constructed for comparison. Unnotched tape equivalents were stronger than braided textiles but exhibited greater notch sensitivity. Notched textiles and tape equivalents have roughly the same strength at large notch sizes. Two common damage mechanisms were found: braider yarn cracking and near notch longitudinal yarn splitting. Cracking was found to initiate in braider yarns in unnotched and notched coupons, and propagate in the direction of the braider yarns until failure. Damage initiation stress decreased with increasing braid angle. No significant differences in prediction of near notch strain between textile and tape equivalents could be detected for small braid angle, but the correlations were weak for textiles with large braid angle. Notch strength could not be predicted using existing anisotropic theory for braided textiles due to their insensitivity to notch.

  6. On the origin of vorticity in magnetic particle suspensions subjected to triaxial fields

    DOE PAGESBeta

    Martin, James E.

    2016-06-06

    We have recently reported that two classes of time-dependent triaxial magnetic fields can induce vorticity in magnetic particle suspensions. The first class – symmetry-breaking fields – is comprised of two ac components and one dc component. The second class – rational triad fields – is comprised of three ac components. In both cases deterministic vorticity occurs when the ratios of the field frequencies form rational numbers. A strange aspect of these fields is that they produce fluid vorticity without generally having a circulating field vector, such as would occur in a rotating field. It has been shown, however, that themore » symmetry of the field trajectory, considered jointly with that of the converse field, allows vorticity to occur around one particular field axis. This axis might be any of the field components, and is determined by the relative frequencies of the field components. However, the symmetry theories give absolutely no insight into why vorticity should occur. In this paper we propose a particle-based model of vorticity in these driven fluids. This model proposes that particles form volatile chains that follow, but lag behind, the dynamic field vector. Furthermore, this model is consistent with the predictions of symmetry theory and gives reasonable agreement with previously reported torque density measurements for a variety of triaxial fields.« less

  7. Imaging and manipulation of nanoscale materials with coaxial and triaxial AFM probes

    NASA Astrophysics Data System (ADS)

    Brown, Keith A.; Westervelt, R. M.

    2011-03-01

    We present coaxial and triaxial Atomic Force Microscope (AFM) probes and demonstrate their applications to imaging and manipulating nanoscale materials. A coaxial probe with concentric electrodes at its tip creates a highly confined electric field that decays as a dipole field, making the coaxial probe useful for near field imaging of electrical properties. We show nearly an order of magnitude improvement in the step resolution of Kelvin probe force microscopy with coaxial probes. We further demonstrate that coaxial probes can image dielectric materials with the dielectrophoretic force. In addition to imaging, the capacitive structure that makes up the cantilever of a coaxial probe is used to locally mechanically drive the probe, making them self-driving probes. Finally, coaxial probes can create strong forces with dielectrophoresis (DEP) which we combine with the nanometer precision of the AFM to create a nanometer scale pick-and-place tool. We demonstrate 3D assembly of micrometer scale objects with coaxial probes using positive DEP and discuss the assembly of nanometer scale objects with triaxial probes using negative DEP.

  8. Application of a tri-axial accelerometer to estimate jump frequency in volleyball.

    PubMed

    Jarning, Jon M; Mok, Kam-Ming; Hansen, Bjørge H; Bahr, Roald

    2015-03-01

    Patellar tendinopathy is prevalent among athletes, and most likely associated with a high jumping load. If methods for estimating jump frequency were available, this could potentially assist in understanding and preventing this condition. The objective of this study was to explore the possibility of using peak vertical acceleration (PVA) or peak resultant acceleration (PRA) measured by an accelerometer to estimate jump frequency. Twelve male elite volleyball players (22.5 ± 1.6 yrs) performed a training protocol consisting of seven typical motion patterns, including jumping and non-jumping movements. Accelerometer data from the trial were obtained using a tri-axial accelerometer. In addition, we collected video data from the trial. Jump-float serving and spike jumping could not be distinguished from non-jumping movements using differences in PVA or PRA. Furthermore, there were substantial inter-participant differences in both the PVA and the PRA within and across movement types (p < 0.05). These findings suggest that neither PVA nor PRA measured by a tri-axial accelerometer is an applicable method for estimating jump frequency in volleyball. A method for acquiring real-time estimates of jump frequency remains to be verified. However, there are several alternative approaches, and further investigations are needed. PMID:25902964

  9. Phase space dynamics of triaxial collapse: joint density-velocity evolution

    NASA Astrophysics Data System (ADS)

    Nadkarni-Ghosh, Sharvari; Singhal, Akshat

    2016-04-01

    We investigate the dynamics of triaxial collapse in terms of eigenvalues of the deformation tensor, the velocity derivative tensor and the gravity Hessian. Using the Bond-Myers model of ellipsoidal collapse, we derive a new set of equations for the nine eigenvalues and examine their dynamics in phase space. The main advantage of this form is that it eliminates the complicated elliptic integrals that appear in the axes evolution equations and is more natural way to understand the interplay between the perturbations. This paper focuses on the density-velocity dynamics. The Zeldovich approximation implies that the three tensors are proportional; the proportionality constant is set by demanding `no decaying modes'. We extend this condition into the non-linear regime and find that the eigenvalues of the gravity Hessian and the velocity derivative tensor are related as {tilde{q}}_d + {tilde{q}}_v=1, where the triaxiality parameter {tilde{q}} = (λ _{max} - λ _{inter})/(λ _{max} - λ _{min}). This is a new universal relation holding true over all redshifts and a range of mass scales to within a few per cent accuracy. The mean density-velocity divergence relation at late times is close to linear, indicating that the dynamics is dictated by collapse along the largest eigendirection. This relation has a scatter, which we show is intimately connected to the velocity shear. Finally, as an application, we compute the PDFs of the two variables and compare with other forms in the literature.

  10. On the origin of vorticity in magnetic particle suspensions subjected to triaxial fields.

    PubMed

    Martin, James E

    2016-07-01

    We have recently reported that two classes of time-dependent triaxial magnetic fields can induce vorticity in magnetic particle suspensions. The first class - symmetry-breaking fields - is comprised of two ac components and one dc component. The second class - rational triad fields - is comprised of three ac components. In both cases deterministic vorticity occurs when the ratios of the field frequencies form rational numbers. A strange aspect of these fields is that they produce fluid vorticity without generally having a circulating field vector, such as would occur in a rotating field. It has been shown, however, that the symmetry of the field trajectory, considered jointly with that of the converse field, allows vorticity to occur around one particular field axis. This axis might be any of the field components, and is determined by the relative frequencies of the field components. However, the symmetry theories give absolutely no insight into why vorticity should occur. In this paper we propose a particle-based model of vorticity in these driven fluids. This model proposes that particles form volatile chains that follow, but lag behind, the dynamic field vector. This model is consistent with the predictions of symmetry theory and gives reasonable agreement with previously reported torque density measurements for a variety of triaxial fields. PMID:27263641

  11. A Modeling Technique and Representation of Failure in the Analysis of Triaxial Braided Carbon Fiber Composites

    NASA Technical Reports Server (NTRS)

    Littell, Justin D.; Binienda, Wieslaw K.; Goldberg, Robert K.; Roberts, Gary D.

    2008-01-01

    Quasi-static tests have been performed on triaxially braided carbon fiber composite materials with large unit cell sizes. The effects of different fibers and matrix materials on the failure mode were investigated. Simulations of the tests have been performed using the transient dynamic finite element code, LS-DYNA. However, the wide range of failure modes observed for the triaxial braided carbon fiber composites during tests could not be simulated using composite material models currently available within LS-DYNA. A macroscopic approach has been developed that provides better simulation of the material response in these materials. This approach uses full-field optical measurement techniques to measure local failures during quasi-static testing. Information from these experiments is then used along with the current material models available in LS-DYNA to simulate the influence of the braided architecture on the failure process. This method uses two-dimensional shell elements with integration points through the thickness of the elements to represent the different layers of braid along with a new analytical method for the import of material stiffness and failure data directly. The present method is being used to examine the effect of material properties on the failure process. The experimental approaches used to obtain the required data will be described, and preliminary results of the numerical analysis will be presented.

  12. A Mode Matched Triaxial Vibratory Wheel Gyroscope with Fully Decoupled Structure

    PubMed Central

    Xia, Dunzhu; Kong, Lun; Gao, Haiyu

    2015-01-01

    To avoid the oscillation of four unequal masses seen in previous triaxial linear gyroscopes, a modified silicon triaxial gyroscope with a rotary wheel is presented in this paper. To maintain a large sensitivity and suppress the coupling of different modes, this novel gyroscope structure is designed be perfectly symmetrical with a relatively large size of about 9.8 mm × 9.8 mm. It is available for differentially detecting three-axis angular rates simultaneously. To overcome the coupling between drive and sense modes, numerous necessary frames, beams, and anchors are delicately figured out and properly arranged. Besides, some frequency tuning and feedback mechanisms are addressed in the case of post processing after fabrication. To facilitate mode matched function, a new artificial fish swarm algorithm (AFSA) performed faster than particle swarm optimization (PSO) with a frequency split of 108 Hz. Then, by entrusting the post adjustment of the springs dimensions to the finite element method (FEM) software ANSYS, the final frequency splits can be below 3 Hz. The simulation results demonstrate that the modal frequencies in drive and different sense modes are respectively 8001.1, 8002.6, 8002.8 and 8003.3 Hz. Subsequently, different axis cross coupling effects and scale factors are also analyzed. The simulation results effectively validate the feasibility of the design and relevant theoretical calculation. PMID:26593916

  13. A Mode Matched Triaxial Vibratory Wheel Gyroscope with Fully Decoupled Structure.

    PubMed

    Xia, Dunzhu; Kong, Lun; Gao, Haiyu

    2015-01-01

    To avoid the oscillation of four unequal masses seen in previous triaxial linear gyroscopes, a modified silicon triaxial gyroscope with a rotary wheel is presented in this paper. To maintain a large sensitivity and suppress the coupling of different modes, this novel gyroscope structure is designed be perfectly symmetrical with a relatively large size of about 9.8 mm × 9.8 mm. It is available for differentially detecting three-axis angular rates simultaneously. To overcome the coupling between drive and sense modes, numerous necessary frames, beams, and anchors are delicately figured out and properly arranged. Besides, some frequency tuning and feedback mechanisms are addressed in the case of post processing after fabrication. To facilitate mode matched function, a new artificial fish swarm algorithm (AFSA) performed faster than particle swarm optimization (PSO) with a frequency split of 108 Hz. Then, by entrusting the post adjustment of the springs dimensions to the finite element method (FEM) software ANSYS, the final frequency splits can be below 3 Hz. The simulation results demonstrate that the modal frequencies in drive and different sense modes are respectively 8001.1, 8002.6, 8002.8 and 8003.3 Hz. Subsequently, different axis cross coupling effects and scale factors are also analyzed. The simulation results effectively validate the feasibility of the design and relevant theoretical calculation. PMID:26593916

  14. Transient thermal analysis of a tri-axial HTS cable on fault current condition

    NASA Astrophysics Data System (ADS)

    Hu, N.; Cao, K.; Wang, D.; Song, M.; Miyagi, D.; Tsuda, M.; Hamajima, T.

    2013-11-01

    High-temperature superconducting (HTS) tri-axial cable, which consists of three concentric phases, was developed as a potential commercial solution for next generation distribution power network. In our previous research, we simulate the transient thermal behavior of the cable by solving the heat equation using one-dimension difference method. The result shows that it takes time to recover the cable temperature to the steady-state operation level due to a low thermal conductivity of the insulation layer after a fault. However for a long cable system, when middle phase in concentric structure is rated under an over current, accumulated heat from middle phase might continually warm up the liquid nitrogen (LN2) flow by heat transfer even the over current has been stopped. In this research, we improve the numerically calculation which includes the consideration of flowing liquid nitrogen and the heat transfer in both radius and longitudinal directions. A long tri-axial cable system thermal stability is discussed based on the calculation results.

  15. Investigation of a Macromechanical Approach to Analyzing Triaxially-Braided Polymer Composites

    NASA Technical Reports Server (NTRS)

    Goldberg, Robert K.; Blinzler, Brina J.; Binienda, Wieslaw K.

    2010-01-01

    A macro level finite element-based model has been developed to simulate the mechanical and impact response of triaxially-braided polymer matrix composites. In the analytical model, the triaxial braid architecture is simulated by using four parallel shell elements, each of which is modeled as a laminated composite. The commercial transient dynamic finite element code LS-DYNA is used to conduct the simulations, and a continuum damage mechanics model internal to LS-DYNA is used as the material constitutive model. The material stiffness and strength values required for the constitutive model are determined based on coupon level tests on the braided composite. Simulations of quasi-static coupon tests of a representative braided composite are conducted. Varying the strength values that are input to the material model is found to have a significant influence on the effective material response predicted by the finite element analysis, sometimes in ways that at first glance appear non-intuitive. A parametric study involving the input strength parameters provides guidance on how the analysis model can be improved.

  16. Characterization and Analysis of Triaxially Braided Polymer Composites under Static and Impact Loads

    NASA Technical Reports Server (NTRS)

    Goldberg, Robert K.; Roberts, Gary D.; Blinzler, Brina J.; Kohlman, Lee W.; Binienda, Wieslaw K.

    2012-01-01

    In order to design impact resistant aerospace components made of triaxially-braided polymer matrix composite materials, a need exists to have reliable impact simulation methods and a detailed understanding of the material behavior. Traditional test methods and specimen designs have yielded unrealistic material property data due to material mechanisms such as edge damage. To overcome these deficiencies, various alternative testing geometries such as notched flat coupons have been examined to alleviate difficulties observed with standard test methods. The results from the coupon level tests have been used to characterize and validate a macro level finite element-based model which can be used to simulate the mechanical and impact response of the braided composites. In the analytical model, the triaxial braid unit cell is approximated by using four parallel laminated composites, each with a different fiber layup, which roughly simulates the braid architecture. In the analysis, each of these laminated composites is modeled as a shell element. Currently, each shell element is considered to be a smeared homogeneous material. Simplified micromechanics techniques and lamination theory are used to determine the equivalent stiffness properties of each shell element, and results from the coupon level tests on the braided composite are used to back out the strength properties of each shell element. Recent improvements to the model include the incorporation of strain rate effects into the model. Simulations of ballistic impact tests have been carried out to investigate and verify the analysis approach.

  17. Attenuation Properties of Fontainebleau Sandstone During True-Triaxial Deformation using Active and Passive Ultrasonics

    NASA Astrophysics Data System (ADS)

    Goodfellow, S. D.; Tisato, N.; Ghofranitabari, M.; Nasseri, M. H. B.; Young, R. P.

    2015-11-01

    Active and passive ultrasonic methods were used to study the evolution of attenuation properties in a sample of Fontainebleau sandstone during true-triaxial deformation. A cubic sample of Fontainebleau sandstone (80 mm × 80 mm × 80 mm) was deformed under true-triaxial stresses until failure. From the stress state: σ _3 = 5 MPa and σ _1 = σ _2 = 35 MPa, σ _1 was increased at a constant displacement rate until the specimen failed. Acoustic emission (AE) activity was monitored by 18 piezoelectric sensors and bandpass filtered between 100 kHz and 1 MHz. A source location analysis was performed on discrete AE data harvested from the continuous record where 48,502 events were locatable inside the sample volume. AE sensors were sequentially pulsed during periodic P-wave surveys among 135 raypaths. Analytical solutions for Biot, squirt flow, viscous shear, and scattering attenuation were used to discuss to observed attenuation at various stages of the experiment. We concluded that initial attenuation anisotropy was stress induced and resulted from friction and squirt flow. Later attenuation of the high-frequency spectrum was attributed to scattering as a result of the formation of large macroscopic vertical fractures. Passive (AE) ultrasonic data produced similar information to that from active data but with enhanced temporal and spacial resolution.

  18. New capacitive low-g triaxial accelerometer with low cross-axis sensitivity

    NASA Astrophysics Data System (ADS)

    Hsu, Yu-Wen; Chen, Jen-Yi; Chien, Hsin-Tang; Chen, Sheah; Lin, Shih-Ting; Liao, Lu-Po

    2010-05-01

    This work describes a compact accelerometer, which integrates three spring-proof mass systems into a single structure to sense triaxial motion. It has a size of 1.3 × 1.28 mm2 and an operating range of ±1 g. Silicon-on-glass (SOG) micromachining and deep reactive-ion etching (DRIE)-based process are adopted to fabricate this accelerometer with a high-aspect-ratio sensing structure. The accelerometer has an excellent z-axis output sensitivity of 1.434 V g-1 and a high resolution of 49 µg Hz-1/2. The sensitivity and minimum cross-axis sensitivity of the x-axis in-plane accelerometer are 1.442 V g-1 and 0.03% and those of the y-axis accelerometer are 1.241 V g-1 and 0.21%, respectively. The new in-plane and out-of-plane accelerometer design exhibits high cross-axis sensitivity immunity, high sensitivity and high linearity suggesting that the triaxial accelerometer has the potential for use in future applications in consumer goods and the cellular phone market.

  19. The dual cycle bridge detection of piezoresistive triaxial accelerometer based on MEMS technology

    NASA Astrophysics Data System (ADS)

    Juanting, Zhang; Changde, He; Hui, Zhang; Yuping, Li; Yongping, Zhang; Chunhui, Du; Wendong, Zhang

    2014-06-01

    A cycle bridge detection method, which uses a piezoresistive triaxial accelerometer, has been described innovatively. This method just uses eight resistors to form a cycle detection bridge, which can detect the signal of the three directions for real time. It breaks the law of the ordinary independent Wheatstone bridge detection method, which uses at least 12 resistors and each four resistors connected as a Wheatstone bridge to detect the output signal from a specific direction. In order to verify the feasibility of this method, the modeling and simulating of the sensor structure have been conducted by ANSYS, then the dual cycle bridge detection method and independent Wheatstone bridge detection method are compared, the result shows that the former method can improve the sensitivity of the sensor effectively. The sensitivity of the x, y-axis used in the former method is two times that of the sensor used in the latter method, and the sensitivity of the z-axis is four times. At the same time, it can also reduce the cross-axis coupling degree of the sensor used in the dual cycle bridge detection method. In addition, a signal amplifier circuit and adder circuit have been provided. Finally, the test result of the “eight-beams/mass” triaxial accelerometer, which is based on the dual cycle bridge detection method and the related circuits, have been provided. The results of the test and the theoretical analysis are consistent, on the whole.

  20. Estimating activity-related energy expenditure under sedentary conditions using a tri-axial seismic accelerometer.

    PubMed

    van Hees, Vincent T; van Lummel, Rob C; Westerterp, Klaas R

    2009-06-01

    Activity-related energy expenditure (AEE) is difficult to quantify, especially under sedentary conditions. Here, a model was developed using the detected type of physical activity (PA) and movement intensity (MI), based on a tri-axial seismic accelerometer (DynaPort MiniMod; McRoberts B.V., The Hague, the Netherlands), with energy expenditure for PA as a reference. The relation between AEE (J/min/kg), MI, and the type of PA was determined for standardized PAs as performed in a laboratory including: lying, sitting, standing, and walking. AEE (J/min/kg) was calculated from total energy expenditure (TEE) and sleeping metabolic rate (SMR) as assessed with indirect calorimetry ((TEEx0.9)-SMR). Subsequently, the model was validated over 23-h intervals in a respiration chamber. Subjects were 15 healthy women (age: 22+/-2 years; BMI: 24.0+/-4.0 kg/m2). Predicted AEE in the chamber was significantly related to measured AEE both within (r2=0.81+/-0.06, P<0.00001) and between (r2=0.70, P<0.001) subjects. The explained variation in AEE by the model was higher than the explained variation by MI alone. This shows that a tri-axial seismic accelerometer is a valid tool for estimating AEE under sedentary conditions. PMID:19282829

  1. From dilatancy to contraction: Stress-dependent failure mode progression in two porous sandstones subjected to true triaxial testing

    NASA Astrophysics Data System (ADS)

    Ma, Xiaodong; Haimson, Bezalel

    2013-04-01

    Porous sedimentary rocks such as sandstones are typical oil-bearing formations in which failure due to high stress concentration is likely to occur during wellbore drilling and subsequent operations. The objective of this research was to investigate the effect of ?2 on strength, failure-plane angle, and failure mode under realistically simulated field conditions (?1 ×?2 ×?3). A series of true triaxial compression tests were conducted on two representative porous sandstones: Coconino (17.5% porosity, 99% quartz, with rounded and well-sorted 0.1 mm grains that are bonded by suturing and some quartz overgrowth), and Bentheim (24% porosity, 95% quartz, with sub-rounded 0.3 mm grains that are bonded exclusively by suturing). Square cuboidal specimens (19 x 19 x 38mm) were subjected to independent loads in three principal directions, using the University of Wisconsin testing apparatus, creating a true triaxial state of stress (?1 ×?2 ×?3). In all tests, ?3 and ?2 were maintained constant at predetermined levels, while ?1 was raised monotonically until failure occurred. The magnitude of ?3 varied between 0 and 150 MPa, covering the range of brittle behavior, brittle-ductile transition, and the threshold to the ductile zone in the weaker Bentheim sandstone. It was found that in both rocks the compressive strength (?1,peak) for a given ?3 increases as the preset ?2 is raised between tests, and reaches a peak (15% over ?1,peak when ?2 = ?3 in the Coconino, and less than 10% in the Bentheim), beyond which it gradually drops, such that when ?2 ? ?1,peak, the strength is approximately the same as when ?2 = ?3. This strengthening effect is considerably lower than that in previously tested crystalline rocks, such as Westerly granite and KTB amphibolite (more than 50%, Haimson, 2006). Plotting the test data in the ?oct vs. ?oct domain, where the two stress invariants ?oct, the octahedral shear stress, and ?oct,the mean normal stress, are both taken at failure), Coconino shows

  2. Effect of Anisotropic Velocity Structure on Acoustic Emission Source Location during True-Triaxial Deformation Experiments

    NASA Astrophysics Data System (ADS)

    Ghofrani Tabari, Mehdi; Goodfellow, Sebastian; Young, R. Paul

    2016-04-01

    Although true-triaxial testing (TTT) of rocks is now more extensive worldwide, stress-induced heterogeneity due to the existence of several loading boundary effects is not usually accounted for and simplified anisotropic models are used. This study focuses on the enhanced anisotropic velocity structure to improve acoustic emission (AE) analysis for an enhanced interpretation of induced fracturing. Data from a TTT on a cubic sample of Fontainebleau sandstone is used in this study to evaluate the methodology. At different stages of the experiment the True-Triaxial Geophysical Imaging Cell (TTGIC), armed with an ultrasonic and AE monitoring system, performed several velocity surveys to image velocity structure of the sample. Going beyond a hydrostatic stress state (poro-elastic phase), the rock sample went through a non-dilatational elastic phase, a dilatational non-damaging elasto-plastic phase containing initial AE activity and finally a dilatational and damaging elasto-plastic phase up to the failure point. The experiment was divided into these phases based on the information obtained from strain, velocity and AE streaming data. Analysis of the ultrasonic velocity survey data discovered that a homogeneous anisotropic core in the center of the sample is formed with ellipsoidal symmetry under the standard polyaxial setup. Location of the transducer shots were improved by implementation of different velocity models for the sample starting from isotropic and homogeneous models going toward anisotropic and heterogeneous models. The transducer shot locations showed a major improvement after the velocity model corrections had been applied especially at the final phase of the experiment. This location improvement validated our velocity model at the final phase of the experiment consisting lower-velocity zones bearing partially saturated fractures. The ellipsoidal anisotropic velocity model was also verified at the core of the cubic rock specimen by AE event location of

  3. Case study of preliminary cyclic load evaluation and triaxial soil testing in offshore wind farm planning

    NASA Astrophysics Data System (ADS)

    Otto, Daniel; Ossig, Benjamin; Kreiter, Stefan; Kouery, Saed; Moerz, Tobias

    2010-05-01

    In 2020 Germany aims to produce 20% of its electrical power trough renewable energy sources. Assigned Offshore Wind farms in the German exclusive economic zone of the North- and the Baltic Sea are important step toward a fulfilment of this goal. However the save erecting of 5-6 MW wind power plants (total construction size: > 200m) in water depth of around 40 m is related to unprecedented technical, logistical and financial challenges. With an intended lifetime expectation of 50 years for the foundations, construction materials and the soils around the foundation are subject to high and continued stresses from self-weight, waves, wind and current. These stresses are not only static, but have also a significant cyclic component. An estimated 250 million cyclic load changes may lead to an accumulation of plastic deformation in the soil that potentially may affect operability or lifespan of the plant. During a preliminary geotechnical site survey of one of the largest (~150 km2) offshore wind project sites within the German Bight (~45 km North off the island Juist) a total of 16 drill cores with in situ cone penetration data and a total sample length of ~800 m where recovered. Preliminary foundation designs and static self weight and lateral load calculations were used to design a cycling triaxial lab testing program on discrete natural soil samples. Individual tests were performed by foundation type and at vertical and lateral load maxima to evaluate the long-term soil behaviour under cyclic load. Tests have been performed on granular, cohesive and intermediate natural soils. Following an introduction to the unique MARUM triaxial apparatus and testing conditions, the cyclic triaxial test results are shown and explained. Furthermore cyclic shear strength and stiffness are compared to their static counterparts. Unique soil behaviour like abrupt partial failure, pore pressure response and unexpected in part load independent cyclic deformation behaviour is discussed and

  4. Full-field Strain Methods for Investigating Failure Mechanisms in Triaxial Braided Composites

    NASA Technical Reports Server (NTRS)

    Littell, Justin D.; Binienda, Wieslaw K.; Goldberg, Robert K.; Roberts, Gary D.

    2008-01-01

    Composite materials made with triaxial braid architecture and large tow size carbon fibers are beginning to be used in many applications, including composite aircraft and engine structures. Recent advancements in braiding technology have led to commercially viable manufacturing approaches for making large structures with complex shape. Although the large unit cell size of these materials is an advantage for manufacturing efficiency, the fiber architecture presents some challenges for materials characterization, design, and analysis. In some cases, the static load capability of structures made using these materials has been higher than expected based on material strength properties measured using standard coupon tests. A potential problem with using standard tests methods for these materials is that the unit cell size can be an unacceptably large fraction of the specimen dimensions. More detailed investigation of deformation and failure processes in large unit cell size triaxial braid composites is needed to evaluate the applicability of standard test methods for these materials and to develop alternative testing approaches. In recent years, commercial equipment has become available that enables digital image correlation to be used on a more routine basis for investigation of full field 3D deformation in materials and structures. In this paper, some new techniques that have been developed to investigate local deformation and failure using digital image correlation techniques are presented. The methods were used to measure both local and global strains during standard straight-sided coupon tensile tests on composite materials made with 12 and 24 k yarns and a 0/+60/-60 triaxial braid architecture. Local deformation and failure within fiber bundles was observed, and this local failure had a significant effect on global stiffness and strength. The matrix material had a large effect on local damage initiation for the two matrix materials used in this investigation

  5. Numerical Simulation of Rock Fracturing under Laboratory True-Triaxial Stress Conditions

    NASA Astrophysics Data System (ADS)

    Ghofrani Tabari, Mehdi; Hazzard, Jim; Young, R. Paul

    2016-04-01

    A True-triaxial test (TTT) also known as polyaxial test was carried out on saturated Fontainebleau sandstone to elevate our knowledge about the role of the intermediate principal stress on deformation, fracturing and failure patterns of the rock using acoustic emission (AE) monitoring. The induced AE activities were studied by location of the AE events and mapping them on the captured features in the post-mortem CT scan images of the failed sample. The time-lapse monitoring of the velocity structure and AE activity in the sample portrayed a deformational path which led to propagation of fractures and formation of failure patterns in the rock. Having these experimental results, we aimed at running a numerical model of our true-triaxial testing system using an Itasca software based on three-dimensional explicit finite-difference method called FLAC3D. The loads were applied at the end of each platen while the steel platens transferred the stress to the surface of the cubic specimen. In order to simulate the failure, randomly distributed strength demonstrated by Mohr-Columb failure criterion was implemented in the spatial elements of the model representing the random distribution of the micro-cracks. During the experiment, pseudo-boundary surfaces were formed along the minimum and intermediate principal stress axes in the rock due to non-uniform distribution of stress as a result of geometrical constraints including the corner effects and friction on the platen-rock surfaces. Both the real AE data as well as the numerical simulation verified that coalescence of micro-cracks mainly occurred around these pseudo-boundaries with highest stress gradients as well as highest velocity gradients in the rock specimen and formed curvi-planar fractures. The rock specimen strength and brittleness in the macro-scale was also obtained from the stress-strain curve which was consistent with the experimental laboratory measurements. Eventually, the failure of the rock specimen was

  6. Tri-Axial Accelerometry and Heart Rate Telemetry: Relation and Agreement with Behavioral Observation in Elementary Physical Education

    ERIC Educational Resources Information Center

    Scruggs, Philip W.; Beveridge, Sandy K.; Clocksin, Brian D.

    2005-01-01

    The relation and agreement of tri-axial accelerometry and heart rate telemetry in measuring moderate to vigorous physical activity were examined in association to behavioral observation during 1st- and 2nd-grade physical education. In Study 1, physical activity measures of heart rate and behavioral observation were collected on 346 participants…

  7. Effect of stress-triaxiality on void growth in dynamic fracture of metals: a molecular dynamics study

    SciTech Connect

    Seppala, E T; Belak, J; Rudd, R E

    2003-10-07

    The effect of stress-triaxiality on growth of a void in a three dimensional single-crystal face-centered-cubic (FCC) lattice has been studied. Molecular dynamics (MD) simulations using an embedded-atom (EAM) potential for copper have been performed at room temperature and using strain controlling with high strain rates ranging from 10{sup 7}/sec to 10{sup 10}/sec. Strain-rates of these magnitudes can be studied experimentally, e.g. using shock waves induced by laser ablation. Void growth has been simulated in three different conditions, namely uniaxial, biaxial, and triaxial expansion. The response of the system in the three cases have been compared in terms of the void growth rate, the detailed void shape evolution, and the stress-strain behavior including the development of plastic strain. Also macroscopic observables as plastic work and porosity have been computed from the atomistic level. The stress thresholds for void growth are found to be comparable with spall strength values determined by dynamic fracture experiments. The conventional macroscopic assumption that the mean plastic strain results from the growth of the void is validated. The evolution of the system in the uniaxial case is found to exhibit four different regimes: elastic expansion; plastic yielding, when the mean stress is nearly constant, but the stress-triaxiality increases rapidly together with exponential growth of the void; saturation of the stress-triaxiality; and finally the failure.

  8. Elastic-plastic deformations of a beam with the SD-effect

    SciTech Connect

    Pavilaynen, Galina V.

    2015-03-10

    The results for the bending of a cantilever beam with the SD-effect under a concentrated load are discussed. To solve this problem, the standard Bernoulli-Euler hypotheses for beams and the Ilyushin model of perfect plasticity are used. The problem is solved analytically for structural steel A40X. The SD-effect for elastic-plastic deformations is studied. The solutions for beam made of isotropic material and material with the SD-effect are compared.

  9. SD-pair shell model study for {sup 126}Xe and {sup 128}Ba

    SciTech Connect

    Meng Xiangfei; Luo Yanan; Wang, Fu-rong; Pan Feng; Draayer, Jerry P.

    2008-04-15

    The SD-pair shell model is employed to study {sup 126}Xe and {sup 128}Ba. The results show that the spectra and electromagnetic transition strengths can be nicely described in terms of a three-parameter Hamiltonian. In our previous paper, we got a conclusion that the SD-pair approximation improves with the number of SD pairs N. This work shows that this conclusion can be extrapolated to the case with N=5.

  10. A generalized Nadai failure criterion for both crystalline and clastic rocks based on true triaxial tests

    NASA Astrophysics Data System (ADS)

    Haimson, Bezalel; Chang, Chandong; Ma, Xiaodong

    2016-04-01

    The UW true triaxial testing system enables the application of independent compressive loads to cuboidal specimens (19×19×38 mm) along three principal directions. We used the apparatus to conduct extensive series of experiments in three crystalline rocks (Westerly granite, KTB amphibolite, and SAFOD granodiorite) and three clastic rocks of different porosities [TCDP siltstone (7%), Coconino sandstone (17%), and Bentheim sandstone (24%)]. For each rock, several magnitudes of σ3 were employed, between 0 MPa and 100-160 MPa, and for every σ3, σ2 was varied from test to test between σ2 = σ3 and σ2=(0.4 to 1.0) σ1.Testing consisted of keeping σ2and σ3constant, and raising σ1to failure (σ1,peak). The results, plotted as σ1,peakvs. σ2for each σ3 used, highlight the undeniable effect of σ2on the compressive failure of rocks. For each level of σ3, the lowest σ2 tested (σ2 = σ3) yielded the data point used for conventional-triaxial failure criterion. However, for the same σ3 and depending on σ2 magnitude, the maximum stress bringing about failure (σ1,peak) may be considerably higher, by as much as 50% in crystalline rocks, or 15% in clastic rocks, over that in a conventional triaxial test. An important consequence is that use of a Mohr-type criterion leads to overly conservative predictions of failure. The true triaxial test results demonstrate that a criterion in terms of all (three principal stresses is necessary to characterize failure. Thus, we propose a 'Generalized Nadai Criterion' (GNC) based on Nadai (1950), i.e. expressed in terms of the two stress invariants at failure (f), τoct,f = βσoct,f, where τoct,f = 1/3[(σ1,peak ‑σ2)2+(σ2 ‑σ3)2+(σ3 ‑σ1,peak)2]0.5 and σoct,f = (σ1,peak + σ2 + σ3)/3, and β is a function that varies from rock to rock. Moreover, the criterion depends also on the relative magnitude of σ2, represented by a parameter b [= (σ2 - σ3)/(σ1,peak - σ3)]. For each octahedral shear stress at failure (

  11. The fracture characteristic of three collinear cracks under true triaxial compression.

    PubMed

    Liu, Jianjun; Zhu, Zheming; Wang, Bo

    2014-01-01

    The mechanical behavior of multicracks under compression has become a very important project in the field of fracture mechanics and rock mechanics. In this paper, experimental and numerical studies on the fracture property of three collinear cracks under compression were implemented. The specimens were a square concrete plate, and the cracks were made by a very thin film. The tests were conducted by using true triaxial loading device. In the numerical study, the Abaqus code was employed. The effect of crack orientation and the confining stress on cracked specimen compressive strength were investigated. The results show that the critical stresses of cracked specimens change with crack inclination angles, and, as the angle is 45°, the critical stress is the lowest; the critical stresses increase with the confining stresses. PMID:24790569

  12. Finite Element Model for Failure Study of Two-Dimensional Triaxially Braided Composite

    NASA Technical Reports Server (NTRS)

    Li, Xuetao; Binienda, Wieslaw K.; Goldberg, Robert K.

    2010-01-01

    A new three-dimensional finite element model of two-dimensional triaxially braided composites is presented in this paper. This meso-scale modeling technique is used to examine and predict the deformation and damage observed in tests of straight sided specimens. A unit cell based approach is used to take into account the braiding architecture as well as the mechanical properties of the fiber tows, the matrix and the fiber tow-matrix interface. A 0 deg / plus or minus 60 deg. braiding configuration has been investigated by conducting static finite element analyses. Failure initiation and progressive degradation has been simulated in the fiber tows by use of the Hashin failure criteria and a damage evolution law. The fiber tow-matrix interface was modeled by using a cohesive zone approach to capture any fiber-matrix debonding. By comparing the analytical results to those obtained experimentally, the applicability of the developed model was assessed and the failure process was investigated.

  13. Experimental and Analytical Characterization of the Macromechanical Response for Triaxial Braided Composite Materials

    NASA Technical Reports Server (NTRS)

    Littell, Justin D.

    2013-01-01

    Increasingly, carbon composite structures are being used in aerospace applications. Their highstrength, high-stiffness, and low-weight properties make them good candidates for replacing many aerospace structures currently made of aluminum or steel. Recently, many of the aircraft engine manufacturers have developed new commercial jet engines that will use composite fan cases. Instead of using traditional composite layup techniques, these new fan cases will use a triaxially braided pattern, which improves case performance. The impact characteristics of composite materials for jet engine fan case applications have been an important research topic because Federal regulations require that an engine case be able to contain a blade and blade fragments during an engine blade-out event. Once the impact characteristics of these triaxial braided materials become known, computer models can be developed to simulate a jet engine blade-out event, thus reducing cost and time in the development of these composite jet engine cases. The two main problems that have arisen in this area of research are that the properties for these materials have not been fully determined and computationally efficient computer models, which incorporate much of the microscale deformation and failure mechanisms, are not available. The research reported herein addresses some of the deficiencies present in previous research regarding these triaxial braided composite materials. The current research develops new techniques to accurately quantify the material properties of the triaxial braided composite materials. New test methods are developed for the polymer resin composite constituent and representative composite coupons. These methods expand previous research by using novel specimen designs along with using a noncontact measuring system that is also capable of identifying and quantifying many of the microscale failure mechanisms present in the materials. Finally, using the data gathered, a new hybrid

  14. Triaxial digital fluxgate magnetometer for NASA applications explorer mission: Results of tests of critical elements

    NASA Technical Reports Server (NTRS)

    Mcleod, M. G.; Means, J. D.

    1977-01-01

    Tests performed to prove the critical elements of the triaxial digital fluxgate magnetometer design were described. A method for improving the linearity of the analog to digital converter portion of the instrument was studied in detail. A sawtooth waveform was added to the signal being measured before the A/D conversion, and averaging the digital readings over one cycle of the sawtooth. It was intended to reduce bit error nonlinearities present in the A/D converter which could be expected to be as much as 16 gamma if not reduced. No such nonlinearities were detected in the output of the instrument which included the feature designed to reduce these nonlinearities. However, a small scale nonlinearity of plus or minus 2 gamma with a 64 gamma repetition rate was observed in the unit tested. A design improvement intended to eliminate this small scale nonlinearity was examined.

  15. Ultrahigh-spin spectroscopy of {sup 159,160}Er: Observation of triaxial strongly deformed structures

    SciTech Connect

    Ollier, J.; Simpson, J.; Wang, X.; Riley, M. A.; Aguilar, A.; Teal, C.; Paul, E. S.; Nolan, P. J.; Petri, M.; Rigby, S. V.; Thomson, J.; Unsworth, C.; Carpenter, M. P.; Janssens, R. V. F.; Kondev, F. G.; Lauritsen, T.; Zhu, S.; Hartley, D. J.; Darby, I. G.; Ragnarsson, I.

    2009-12-15

    Three weakly populated high-spin rotational bands associated with the {gamma} decay of {sup 159}Er and {sup 160}Er were observed in fusion-evaporation reactions involving a beam of {sup 48}Ca at an energy of 215 MeV incident on a {sup 116}Cd target. The {gamma} decays were detected using the highly efficient Gammasphere spectrometer. The discovery of these bands, which extend discrete-line spectroscopy in these nuclei to ultrahigh spin of {approx}60({Dirac_h}/2{pi}), is consistent with recent observations of high-spin collective structures in isotopes of Er, Yb, and Tm around N=90. Cranked Nilsson-Strutinsky calculations suggest that these bands may arise from well-deformed triaxial configurations with either positive or negative {gamma} deformation.

  16. Triaxiality and shape coexistence in the A ~ 30 island of inversion nuclei

    NASA Astrophysics Data System (ADS)

    Dong, GuoXiang; Wang, XiaoBao; Yu, ShaoYing

    2015-11-01

    Understanding the properties of nuclei inside "island of inversion" is still an interesting issue. Based on a simple Nilsson model with a new set of isospin-dependent parameters, and with non-axial deformations considered, we have performed three-dimensional potential-energy-surface calculations for Ne, Na, Mg and Al isotopes that are claimed to be in or nearby the A ~ 30 island of inversion. It is found that shape coexistence and triaxial deformation (or softness) exist in these nuclei. Large deformations are obtained by the improved Nilsson parameters, which explains the observed large electric quadrupole transition probabilities. The large deformations happening in 30Ne, 31Na, 32Mg and 33Al indicate the quenching of the spherical N = 20 neutron shell gap. The calculations of nuclear binding and two-neutron separation energies have been also improved with the isospin-dependent parameters and the inclusion of the non-axial deformation degree of freedom.

  17. A comparison of methods to detect postural transitions using a single tri-axial accelerometer.

    PubMed

    Godfrey, Alan; Barry, Gillian; Mathers, John C; Rochester, Lynn

    2014-01-01

    Two algorithms for evaluating postural transitions (PTs) in cohorts of 40 healthy younger and 40 older adults are described and evaluated. The time of sit-to-stand (SiSt) and stand-to-sit (StSi) transitions and their duration were measured with two tri-axial accelerometers, one on the chest and one on the lower back. Each algorithm was optimized for these sensor placements. The first algorithm for sensor placement on the chest used a scalar product and vertical velocity estimates. The second algorithm for sensor placement on the lower back used a vector magnitude and a discrete wavelet transform. Both algorithms performed excellently in PT classification for younger and older adults (>86%). However, the chest based sensor and algorithm were better for estimating transition duration (TD) with ICCs to video analysis ranging from 0.678 to 0.969. PMID:25571421

  18. The effects of compressive sensing on extracted features from tri-axial swallowing accelerometry signals

    NASA Astrophysics Data System (ADS)

    Sejdić, Ervin; Movahedi, Faezeh; Zhang, Zhenwei; Kurosu, Atsuko; Coyle, James L.

    2016-05-01

    Acquiring swallowing accelerometry signals using a comprehensive sensing scheme may be a desirable approach for monitoring swallowing safety for longer periods of time. However, it needs to be insured that signal characteristics can be recovered accurately from compressed samples. In this paper, we considered this issue by examining the effects of the number of acquired compressed samples on the calculated swallowing accelerometry signal features. We used tri-axial swallowing accelerometry signals acquired from seventeen stroke patients (106 swallows in total). From acquired signals, we extracted typically considered signal features from time, frequency and time-frequency domains. Next, we compared these features from the original signals (sampled using traditional sampling schemes) and compressively sampled signals. Our results have shown we can obtain accurate estimates of signal features even by using only a third of original samples.

  19. The effects of specimen width on tensile properties of triaxially braided textile composites

    NASA Technical Reports Server (NTRS)

    Masters, John E.; Ifju, Peter G.; Pastore, Christopher M.; Bogdanovich, Alexander E.

    1993-01-01

    The objective of this study was to examine the effect of the unit cell architecture on the mechanical response of textile reinforced composite materials. Specifically, the study investigated the effect of unit cell size on the tensile properties of 2D triaxially braided graphite epoxy laminates. The figures contained in this paper reflect the presentation given at the conference. They may be divided into four sections: (1) a short definition of the material system tested; (2) a statement of the problem and a review of the experimental results; (3) experimental results consist of a Moire interferometry study of the strain distribution in the material plus modulus and strength measurements; and (4) a short summary and a description of future work will close the paper.

  20. Transition saddle points and associated defects for a triaxially stretched FCC crystal

    NASA Astrophysics Data System (ADS)

    Delph, T. J.; Zimmerman, J. A.

    2016-05-01

    We demonstrate the use of a single-ended method for locating saddle points on the potential energy surface for a triaxially stretched FCC crystal governed by a Lennard-Jones potential. Single-ended methods require no prior knowledge of the defected state and are shown to have powerful advantages in this application, principally because the nature of the associated defects can be quite complicated and hence extremely difficult to predict ab initio. We find that while classical spherical cavitation occurs for high stretch values, for lower values the defect mode transitions to a non-spherical pattern without any apparent symmetries. This non-spherical mode plays the primary role in harmonic transition state theory predictions that are used to examine how instabilities vary with applied loading rate. Such a defect mode would be difficult to determine using double-ended methods for finding saddle points.

  1. A Table-Shaped Tactile Sensor for Detecting Triaxial Force on the Basis of Strain Distribution

    PubMed Central

    Lee, Jeong Il; Kim, Min-Gyu; Shikida, Mitsuhiro; Sato, Kazuo

    2013-01-01

    A slim and flexible tactile sensor applicable to the interaction of human and intelligent robots is presented. In particular, a simple sensing principle for decoupling of three-dimensional force is proposed. Sensitivity of the proposed tactile sensor is tested experimentally. To improve the sensitivity of the sensor, a table-shaped sensing element was designed. Table-shaped structure can convert an external acting force into concentrated internal stress. A “triaxial force decoupling algorithm” was developed by combining two-dimensional mapping data calculated by finite element analysis. The sensor was calibrated under normal and tangential forces. The external loads applied to the sensor could be decoupled independently as a function of the strain-gauge responses. PMID:24287546

  2. Genetics Home Reference: multiple system atrophy

    MedlinePlus

    ... OPCA progressive autonomic failure with multiple system atrophy SDS Shy-Drager syndrome sporadic olivopontocerebellar atrophy Related Information ... A, Hulot JS, Morrison KE, Renton A, Sussmuth SD, Landwehrmeyer BG, Ludolph A, Agid Y, Brice A, ...

  3. Microcrack evolution and brittle failure of Inada granite in triaxial compression tests at 140 MPa

    NASA Astrophysics Data System (ADS)

    Oda, M.; Katsube, T.; Takemura, T.

    2002-10-01

    A tensorial measure, called the crack tensor, is proposed to objectively define the crack geometry in crystalline rock as general as possible. Change of crack populations during brittle failure of rock (Inada granite) is analyzed in terms of the crack tensor and its invariants, which can be evaluated by a conventional petrographic analysis combined with stereology. A crack evolution law is formulated as a function of inelastic strain, so that we can easily depict how much damage accumulates in a sample loaded in a triaxial vessel by measuring the inelastic strain. When rock is loaded up to failure, the crack population satisfies a unique relation in the plot of the crack density versus the anisotropy, which are defined using the invariants of the crack tensors. It is suggested that failure of rock in uniaxial compression may be determined by a local condition such as a stress intensity factor at a crack tip. In the triaxial tests, on the other hand, rock fails when the crack density increases over a threshold value, which is a global condition depending on all cracks existing at failure. The threshold density is about 7 for the rock subjected to differential stress under confining pressures larger than 25 MPa. Under such a high crack density, the rock does not behave like a cracked solid, but rather like an assembly of rock blocks (granular material), and it starts to fail mainly due to the structurally induced instability, not due to the critical stress intensity factor at a crack tip. A throughgoing fault may develop as a result of the relative motion among the disintegrated blocks, sliding and rolling.

  4. On the Components of Segregation Distortion in DROSOPHILA MELANOGASTER. II. Deletion Mapping and Dosage Analysis of the SD Locus

    PubMed Central

    Brittnacher, John G.; Ganetzky, Barry

    1983-01-01

    Segregation distorter (SD) chromosomes are preferentially transmitted to offspring from heterozygous SD/SD+ males owing to the induced dysfunction of the SD+-bearing sperm. This phenomenon involves at least two major loci: the Sd locus whose presence is necessary for distortion to occur and the Rsp locus which acts as the site of Sd action. Several additional loci on SD chromosomes enhance distortion.—In a previous study deletions were used to map the Sd locus and to determine some of its properties. We have extended this analysis with the isolation and characterization of 14 new deletions in the Sd region. From our results we conclude (1) SD chromosomes contain a single Sd locus located in region 37D2-6 of the salivary gland chromosome map. Deletion of this locus in any of three SD chromosomes now studied results in complete loss of ability to distort a sensitive chromosome; (2) the reduced male fecundity observed in many homozygous SD or SDi/SDj combinations is due at least in part to the action of the Sd locus. The fecundity of these males can be substantially increased by deletion of one Sd locus. Thus, it is the presence of two doses of Sd rather than the absence of Sd+ that produces the lowered male fecundity in SD homozygotes; (3) Sd behaves as a neomorph, whereas Sd+, if it exists at all, is amorphic with respect to segregation distortion; (4) these results support a model in which the Sd product is made in limiting amounts and the interaction of this product with the Rsp locus causes sperm dysfunction. The Sd product appears to act preferentially at Rsps (sensitive-Responder) but may also act at Rspi (insensitive-Responder). PMID:17246120

  5. Cytokeratin 8 in Association with sdLDL and ELISA Development

    PubMed Central

    Ashmaig, Mohmed

    2015-01-01

    Background: Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality worldwide. Cytokeratins (CKs) which may also be expressed in vascular smooth muscle cells (SMCs) are generally considered to be markers for the differentiation of epithelial cells. Small, dense, low-density lipoprotein (sdLDL) particles, also termed LDL-IV, independently predict risk of CVD. Aims: The aims of this study were to develop an analytical method, apart from ultracentrifugation capable of isolating sdLDL in order to study any associated proteins. Materials and Methods: Using modified gradient gel electrophoresis (GGE), de-identified sdLDL-enriched plasma was used to physically elute and isolate sdLDL particles. To validate the finding, additional plasma from 77 normal and 48 higher risk subjects were used to measure sdLDL particles and CK8. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting method were used to identify the characteristics of proteins associated with sdLDL. An enzyme-linked immunosorbent assay (ELISA) method was developed and validated for the measurement of CK8 in plasma. Results: The validation of the CK8 ELISA method showed good analytical performance. The isolated sdLDL particles were verified with nondenaturing GGE with the apolipoprotein B component confirmed by Western immunoblotting. Confirmed by SDS-PAGE and Western immunoblotting, CK8 was associated with sdLDL. Two-tailed statistical analysis showed that CK8 and sdLDL particles were significantly higher in the high-risk CVD group compared to control group (P < 0.01 and P < 0.01, respectively). Conclusion: This study reports a novel association between CK8 and sdLDL in individuals with CVD who have a predominance of sdLDL. PMID:26713292

  6. Quantum phase transitional patterns in the SD-pair shell model

    SciTech Connect

    Luo Yanan; Meng Xiangfei; Zhang Yu; Pan Feng; Draayer, Jerry P.

    2009-07-15

    Patterns of shape-phase transition in the proton-neutron coupled systems are studied within the SD-pair shell model. The results show that some transitional patterns in the SD-pair shell model are similar to the U(5)-SU(3) and U(5)-SO(6) transitions with signatures of the critical point symmetry of the interacting boson model.

  7. 32. DETAIL OF WALL SHOWN IN SD231. BEHIND WALL FRAMING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    32. DETAIL OF WALL SHOWN IN SD-2-31. BEHIND WALL FRAMING IS SAMPLING ROOM WITH WOOD SAMPLING ELEVATOR. CRUSHED OXIDIZED ORE BIN ON LEFT (SOUTH). - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

  8. HOW TO MAKE A SINGLETON sdB STAR VIA ACCELERATED STELLAR EVOLUTION

    SciTech Connect

    Clausen, Drew; Wade, Richard A. E-mail: wade@astro.psu.edu

    2011-06-01

    Many hot subdwarf B stars (sdBs) are in close binaries, and the favored formation channels for subdwarfs rely on mass transfer in a binary system to strip a core He-burning star of its envelope. However, these channels cannot account for sdBs that have been observed in long-period binaries nor the narrow mass distribution of isolated (or 'singleton') sdBs. We propose a new formation channel involving the merger of a helium white dwarf and a low-mass, hydrogen-burning star, which addresses these issues. Hierarchical triples whose inner binaries merge and form sdBs by this process could explain the observed long-period subdwarf+main-sequence binaries. This process would also naturally explain the observed slow rotational speeds of singleton sdBs. We also briefly discuss the implications of this formation channel for extreme horizontal branch morphology in globular clusters and the UV upturn in elliptical galaxies.

  9. Novel triaxial structure in low-lying states of neutron-rich nuclei around A ≈100

    NASA Astrophysics Data System (ADS)

    Xiang, J.; Yao, J. M.; Fu, Y.; Wang, Z. H.; Li, Z. P.; Long, W. H.

    2016-05-01

    Background: In recent years, the study of triaxiality in the low-lying states of atomic nuclei with transition character or shape coexistence has been of great interest. Previous studies indicate that the neutron-rich nuclei in the A ˜100 mass region with Z ˜40 ,N ˜60 serve as good grounds for examining the role of triaxiality in nuclear low-lying states. Purpose: The aim of this work is to provide a microscopic study of low-lying states for nuclei in the A ˜100 mass regions and to examine in detail the role of triaxiality in the shape-coexistence phenomena and the variation of shape with the isospin and spin values at the beyond mean-field level. Method: The starting point of our method is a set of relativistic mean-field plus BCS wave functions generated with a constraint on triaxial deformations (β ,γ ) . The excitation energies and electric multipole transition strengths of low-lying states are calculated by solving a five-dimensional collective Hamiltonian (5DCH) with parameters determined by the mean-field wave functions. Results: The low-lying states of Mo isotopes and of N =60 isotones in the A ˜100 mass region are calculated. The results indicate that triaxiality is essential to reproduce the data of excitation energies and electric quadrupole transition strengths in low-lying states and plays an important role in the shape evolution as a function of nucleon number. However, the decrease of nuclear collectivity with the increase of angular momentum in neutron-rich Mo isotopes has not been reproduced. Conclusions: The evolution of nuclear collectivity in the low-lying states of neutron-rich nuclei in the A ˜100 mass region as a function of nucleon number is governed by the novel triaxial structure. However, the mechanism that governs the variation of nuclear shape with spin in Mo isotopes remains unclear and deserves further investigation by taking into account the effects other than the collective motions.

  10. Bar formation and evolution in disc galaxies with gas and a triaxial halo: morphology, bar strength and halo properties

    NASA Astrophysics Data System (ADS)

    Athanassoula, E.; Machado, Rubens E. G.; Rodionov, S. A.

    2013-03-01

    We follow the formation and evolution of bars in N-body simulations of disc galaxies with gas and/or a triaxial halo. We find that both the relative gas fraction and the halo shape play a major role in the formation and evolution of the bar. In gas-rich simulations, the disc stays near-axisymmetric much longer than in gas-poor ones, and, when the bar starts growing, it does so at a much slower rate. Because of these two effects combined, large-scale bars form much later in gas-rich than in gas-poor discs. This can explain the observation that bars are in place earlier in massive red disc galaxies than in blue spirals. We also find that the morphological characteristics in the bar region are strongly influenced by the gas fraction. In particular, the bar at the end of the simulation is much weaker in gas-rich cases. The quality of our simulations is such as to allow us to discuss the question of bar longevity because the resonances are well resolved and the number of gas particles is sufficient to describe the gas flow adequately. In no case did we find a bar which was destroyed. Halo triaxiality has a dual influence on bar strength. In the very early stages of the simulation it induces bar formation to start earlier. On the other hand, during the later, secular evolution phase, triaxial haloes lead to considerably less increase of the bar strength than spherical ones. The shape of the halo evolves considerably with time. We confirm previous results of gas-less simulations that find that the inner part of an initially spherical halo can become elongated and develop a halo bar. However we also show that, on the contrary, in gas-rich simulations, the inner parts of an initially triaxial halo can become rounder with time. The main body of initially triaxial haloes evolves towards sphericity, but in initially strongly triaxial cases it stops well short of becoming spherical. Part of the angular momentum absorbed by the halo generates considerable rotation of the halo

  11. Mineralogic variation in drill holes USW NRG-6, NRG-7/7a, SD-7, SD-9, SD-12, and UZ{number_sign}14: New data from 1996--1997 analyses

    SciTech Connect

    Chipera, S.J.; Vaniman, D.T.; Bish, D.L.; Carey, J.W.

    1997-05-30

    New quantitative X-ray diffraction (QXRD) mineralogic data have been obtained for samples from drill holes NRG-6, NRG-7/7A, SD-7, SD-9, SD- 12, and UZ{number_sign}14. In addition, new QXRD analyses were obtained on samples located in a strategic portion of drill hole USW H-3. These data improve our understanding of the mineral stratigraphy at Yucca Mountain, and they further constrain the 3-D Mineralogic Model of Yucca Mountain. Some of the unexpected findings include the occurrence of the zeolite chabazite in the vitric zone of USW SD-7, broad overlap of vitric and zeolitic horizons (over vertical ranges up to 70 m), and the previously unrecognized importance of the bedded tuft beneath the Calico Hills Formation as a subunit with generally more extensive zeolitization than the Calico Hills Formation in the southern part of the potential repository area. Reassessment of data from drill hole USW H-5 suggests that the zeolitization of this bedded unit occurs in the northwestern part of the repository exploration block as well. Further analyses of the same interval in USW H-3, however, have not permitted the same conclusion to be reached for the southwestern part of the repository block because of the much poorer quality of the cuttings in H-3 compared with those from H-5. X-ray fluorescence (XRF) chemical data for drill holes USW SD-7, 9, and 12 show that the zeolitic horizons provide a >10 million year record of retardation of Sr transport, although the data also show that simplistic models of one-dimensional downward flow in the unsaturated zone (UZ) are inadequate. Complex interstratification of zeolites and glass, with highly variable profiles between drill cores, point to remaining problems in constructing detailed mineral stratigraphies. However, the new data in this report provide important information for constructing bounding models of zeolite stratigraphy for transport calculations.

  12. Evidence for Octupole Correlations in Multiple Chiral Doublet Bands.

    PubMed

    Liu, C; Wang, S Y; Bark, R A; Zhang, S Q; Meng, J; Qi, B; Jones, P; Wyngaardt, S M; Zhao, J; Xu, C; Zhou, S-G; Wang, S; Sun, D P; Liu, L; Li, Z Q; Zhang, N B; Jia, H; Li, X Q; Hua, H; Chen, Q B; Xiao, Z G; Li, H J; Zhu, L H; Bucher, T D; Dinoko, T; Easton, J; Juhász, K; Kamblawe, A; Khaleel, E; Khumalo, N; Lawrie, E A; Lawrie, J J; Majola, S N T; Mullins, S M; Murray, S; Ndayishimye, J; Negi, D; Noncolela, S P; Ntshangase, S S; Nyakó, B M; Orce, J N; Papka, P; Sharpey-Schafer, J F; Shirinda, O; Sithole, P; Stankiewicz, M A; Wiedeking, M

    2016-03-18

    Two pairs of positive-and negative-parity doublet bands together with eight strong electric dipole transitions linking their yrast positive- and negative-parity bands have been identified in ^{78}Br. They are interpreted as multiple chiral doublet bands with octupole correlations, which is supported by the microscopic multidimensionally-constrained covariant density functional theory and triaxial particle rotor model calculations. This observation reports the first example of chiral geometry in octupole soft nuclei. PMID:27035296

  13. Evidence for Octupole Correlations in Multiple Chiral Doublet Bands

    NASA Astrophysics Data System (ADS)

    Liu, C.; Wang, S. Y.; Bark, R. A.; Zhang, S. Q.; Meng, J.; Qi, B.; Jones, P.; Wyngaardt, S. M.; Zhao, J.; Xu, C.; Zhou, S.-G.; Wang, S.; Sun, D. P.; Liu, L.; Li, Z. Q.; Zhang, N. B.; Jia, H.; Li, X. Q.; Hua, H.; Chen, Q. B.; Xiao, Z. G.; Li, H. J.; Zhu, L. H.; Bucher, T. D.; Dinoko, T.; Easton, J.; Juhász, K.; Kamblawe, A.; Khaleel, E.; Khumalo, N.; Lawrie, E. A.; Lawrie, J. J.; Majola, S. N. T.; Mullins, S. M.; Murray, S.; Ndayishimye, J.; Negi, D.; Noncolela, S. P.; Ntshangase, S. S.; Nyakó, B. M.; Orce, J. N.; Papka, P.; Sharpey-Schafer, J. F.; Shirinda, O.; Sithole, P.; Stankiewicz, M. A.; Wiedeking, M.

    2016-03-01

    Two pairs of positive-and negative-parity doublet bands together with eight strong electric dipole transitions linking their yrast positive- and negative-parity bands have been identified in 78Br. They are interpreted as multiple chiral doublet bands with octupole correlations, which is supported by the microscopic multidimensionally-constrained covariant density functional theory and triaxial particle rotor model calculations. This observation reports the first example of chiral geometry in octupole soft nuclei.

  14. Effect of Microscopic Damage Events on Static and Ballistic Impact Strength of Triaxial Braid Composites

    NASA Technical Reports Server (NTRS)

    Littell, Justin D.; Binienda, Wieslaw K.; Arnold, William A.; Roberts, Gary d.; Goldberg, Robert K.

    2008-01-01

    In previous work, the ballistic impact resistance of triaxial braided carbon/epoxy composites made with large flat tows (12k and 24k) was examined by impacting 2 X2 X0.125" composite panels with gelatin projectiles. Several high strength, intermediate modulus carbon fibers were used in combination with both untoughened and toughened matrix materials. A wide range of penetration thresholds were measured for the various fiber/matrix combinations. However, there was no clear relationship between the penetration threshold and the properties of the constituents. During some of these experiments high speed cameras were used to view the failure process, and full-field strain measurements were made to determine the strain at the onset of failure. However, these experiments provided only limited insight into the microscopic failure processes responsible for the wide range of impact resistance observed. In order to investigate potential microscopic failure processes in more detail, quasi-static tests were performed in tension, compression, and shear. Full-field strain measurement techniques were used to identify local regions of high strain resulting from microscopic failures. Microscopic failure events near the specimen surface, such as splitting of fiber bundles in surface plies, were easily identified. Subsurface damage, such as fiber fracture or fiber bundle splitting, could be identified by its effect on in-plane surface strains. Subsurface delamination could be detected as an out-of-plane deflection at the surface. Using this data, failure criteria could be established at the fiber tow level for use in analysis. An analytical formulation was developed to allow the microscopic failure criteria to be used in place of macroscopic properties as input to simulations performed using the commercial explicit finite element code, LS-DYNA. The test methods developed to investigate microscopic failure will be presented along with methods for determining local failure criteria

  15. Plastic cap evolution law derived from induced transverse isotropy in dilatational triaxial compression.

    SciTech Connect

    Macon, David James; Brannon, Rebecca Moss; Strack, Otto Eric

    2014-02-01

    Mechanical testing of porous materials generates physical data that contain contributions from more than one underlying physical phenomenon. All that is measurable is the (3z(Bensemble(3y (Bhardening modulus. This thesis is concerned with the phenomenon of dilatation in triaxial compression of porous media, which has been modeled very accurately in the literature for monotonic loading using models that predict dilatation under triaxial compression (TXC) by presuming that dilatation causes the cap to move outwards. These existing models, however, predict a counter-intuitive (and never validated) increase in hydrostatic compression strength. This work explores an alternative approach for modeling TXC dilatation based on allowing induced elastic anisotropy (which makes the material both less stiff and less strong in the lateral direction) with no increase in hydrostatic strength. Induced elastic anisotropy is introduced through the use of a distortion operator. This operator is a fourth-order tensor consisting of a combination of the undeformed stiffness and deformed compliance and has the same eigenprojectors as the elastic compliance. In the undeformed state, the distortion operator is equal to the fourth-order identity. Through the use of the distortion operator, an evolved stress tensor is introduced. When the evolved stress tensor is substituted into an isotropic yield function, a new anisotropic yield function results. In the case of the von Mises isotropic yield function (which contains only deviatoric components), it is shown that the distortion operator introduces a dilatational contribution without requiring an increase in hydrostatic strength. In the thesis, an introduction and literature review of the cap function is given. A transversely isotropic compliance is presented, based on a linear combination of natural bases constructed about a transverse-symmetry axis. Using a probabilistic distribution of cracks constructed for the case of transverse isotropy

  16. Integral equation model of light scattering by an oriented monodisperse system of triaxial dielectric ellipsoids: application in ectacytometry.

    PubMed

    Stamatakos, G S; Yova, D; Uzunoglu, N K

    1997-09-01

    A novel mathematical model of light scattering by an oriented monodisperse system of triaxial dielectric ellipsoids of complex index of refraction is presented. It is based on an integral equation solution to the scattering of a plane electromagnetic wave by a single triaxial dielectric ellipsoid. Both the position and the orientation of a single representative scatterer in a given coordinate system are considered arbitrary. A Monte Carlo simulation is developed to reproduce the diffraction pattern of a population of aligned ellipsoids. As an example of practical importance, light scattering by a population of erythrocytes subjected to intense shear stress is modeled. Agreement with experimental observations and the anomalous diffraction theory is illustrated. Thus a novel check of the electromagnetic basis of ektacytometry is provided. Furthermore, the versatility of the integral equation method, particularly in the advent of parallel processing systems, is demonstrated. PMID:18259511

  17. Generalized ray matrix for spherical mirror reflection and its application in square ring resonators and monolithic triaxial ring resonators.

    PubMed

    Yuan, Jie; Long, Xingwu; Chen, Meixiong

    2011-03-28

    To the best of our knowledge, the generalized ray matrix, an augmented 5×5 ray matrix for a spherical mirror reflection with all the possible perturbation sources including three kinds of displacements and its detailed deducing process have been proposed in this paper for the first time. Square ring resonators and monolithic triaxial ring resonators have been chosen as examples to show its application, and some novel results of the optical-axis perturbation have been obtained. A novel method to eliminate the diaphragm mismatching error and the gain capillary mismatching error in monolithic triaxial ring resonators more effectively has also been proposed. Both those results and method have been confirmed by related experiments and the experimental results have been described with diagrammatic representation. This generalized ray matrix is valuable for ray analysis of various kinds of resonators. These results are important for the cavity design, cavity improvement and alignment of high accuracy and super high accuracy ring laser gyroscopes. PMID:21451703

  18. New code for equilibriums and quasiequilibrium initial data of compact objects. III. Axisymmetric and triaxial rotating stars

    NASA Astrophysics Data System (ADS)

    Uryū, Kōji; Tsokaros, Antonios; Galeazzi, Filippo; Hotta, Hideya; Sugimura, Misa; Taniguchi, Keisuke; Yoshida, Shin'ichirou

    2016-02-01

    We introduce new code for stationary and axisymmetric equilibriums, as well as for triaxial quasiequilibrium initial data, of single rotating relativistic stars. The new code is developed as a part of our versatile initial data code for compact objects, Compact Object CALculator (cocal). In computing strong gravitational fields, the waveless formulation is incorporated into the cocal code on top of the previously developed Isenberg-Wilson-Mathews formulation (conformally flat thin-sandwich formulation). Also introduced is a new differential rotation law that contains two parameters to control an angular velocity profile and a transition from uniform to differential rotation. We present convergence tests and solution sequences for both uniformly and differentially rotating equilibriums of stationary axisymmetric compact stars, as well as for quasiequilibrium initial data of uniformly rotating triaxial (nonaxisymmetric) compact stars. We also show comparisons of uniformly rotating axisymmetric solutions computed with three different codes: cocal, lorene, and the RNS code.

  19. The Influence of Triaxiality Parameter γ on the Chiral Doublet Bands with (πg9/2)-1 (νh11/2)2 Configuration

    NASA Astrophysics Data System (ADS)

    Qi, Bin; Wang, Shouyu; Zhao, Xingyan; Zhu, Xiaoying; Sun, Dapeng; Liu, Chen; Xu, Changjiang

    2012-07-01

    The chiral doublet bands with three-quasiparticle configuration (πg9/2)-1 (νh11/2)2 are studied by the fully quantal triaxial particle rotor model. The energy spectra and B(M1)/B(E2) ratios of the doublet bands with different triaxiality parameter γ are systematically analyzed. It is found that γ is a sensitive parameter for the properties of these doublet bands.

  20. New Mechanism for the Enhancement of sd Dominance in Interacting Boson Models

    NASA Astrophysics Data System (ADS)

    Dukelsky, J.; Pittel, S.

    2001-05-01

    We introduce an exactly solvable model for interacting bosons that extend up to high spin and interact through a repulsive pairing force. The model exhibits a phase transition to a state with almost complete sd dominance. The repulsive pairing interaction that underlies the model has a natural microscopic origin in the Pauli exclusion principle between constituent nucleons. As such, repulsive pairing between bosons seems to provide a new mechanism for the enhancement of sd dominance, giving further support for the validity of the sd interacting boson model.

  1. Silicon nanowire-based ring-shaped tri-axial force sensor for smart integration on guidewire

    NASA Astrophysics Data System (ADS)

    Han, Beibei; Yoon, Yong-Jin; Hamidullah, Muhammad; Tsu-Hui Lin, Angel; Park, Woo-Tae

    2014-06-01

    A ring-shaped tri-axial force sensor with a 200 µm × 200 µm sensor area using silicon nanowires (SiNWs) as piezoresistive sensing elements is developed and characterized. The sensor comprises a suspended ring structure located at the center of four suspended beams that can be integrated on the distal tip of a guidewire by passing through the hollow core of the sensor. SiNWs with a length of 6 µm and a cross section of 90 nm × 90 nm are embedded at the anchor of each silicon bridge along <1 1 0> direction as the piezoresistive sensing element. Finite element analysis has been used to determine the location of maximum stress and the simulation results are verified with the experimental measurements. Taking advantage of the high sensitivity of SiNWs, the fabricated ring-shaped sensor is capable of detecting small displacement in nanometer ranges with a sensitivity of 13.4 × 10-3 µm-1 in the z-direction. This tri-axial force sensor also shows high linearity (>99.9%) to the applied load and no obvious hysteresis is observed. The developed SiNW-based tri-axial force sensor provides new opportunities to implement sensing capability on medical instruments such as guidewires and robotic surgical grippers, where ultra-miniaturization and high sensitivity are essential.

  2. Self-Consistent Tilted-Axis-Cranking Study of Triaxial Strongly Deformed Bands in ^{158}Er at Ultrahigh Spin

    SciTech Connect

    Shi, Yue; Dobaczewski, J.; Frauendorf, S.; Nazarewicz, Witold; Pei, J. C.; Xu, F. R.; Nikolov, N.

    2012-01-01

    Stimulated by recent experimental discoveries, triaxial strongly deformed (TSD) states in ^{158}Er at ultrahigh spins have been studied by means of the Skyrme-Hartree-Fock model and the tilted-axis-cranking method. Restricting the rotational axis to one of the principal axes - as done in previous cranking calculations - two well-defined TSD minima in the total Routhian surface are found for a given configuration: one with positive and another with negative triaxial deformation gamma. By allowing the rotational axis to change direction, the higher-energy minimum is shown to be a saddle point. This resolves the long-standing question of the physical interpretation of the two triaxial minima at a very similar quadrupole shape obtained in the principal axis cranking approach. Several TSD configurations have been predicted, including a highly deformed band expected to cross lesser elongated TSD bands at the highest spins. Its transitional quadrupole moment Q_{t} ~ 10.5 eb is close to the measured value of ~11 eb; hence, it is a candidate for the structure observed in experiment.

  3. The Triaxial Ellipsoid Diameters and Rotational Pole of Asteroid (9) Metis from AO at Gemini and Keck

    NASA Astrophysics Data System (ADS)

    Drummond, Jack D.; Merline, W. J.; Conrad, A.; Dumas, C.; Tamblyn, P.; Christou, J.; Carry, B.; Chapman, C.

    2012-10-01

    From Adaptive Optics (AO) images of (9) Metis at 14 epochs over 2008 December 8 and 9 at Gemini North, triaxial ellipsoid diameters of 218x175x112 km are derived with fitting uncertainties of 3x3x47 km. However, by including just two more AO images from Keck-II in June and August of 2003 in a global fit, the fitting uncertainty of the small axis drops by more than a third because of the lower sub-Earth latitude afforded in 2003 (-28°) compared to 2008 (+47°), and the triaxial ellipsoid diameters become 218x175x129 km with fitting uncertainties of 3x3x14 km. We have estimated the systematic uncertainty of our method to be 4.1, 2.7, and 3.8%, respectively, for the three diameters. These values were recently derived (Drummond et al., in prep) from a comparison of KOALA (Carry et al, Planetary and Space Science 66, 200-212) and our triaxial ellipsoid analysis of four asteroids. Quadratically adding this systematic error with the fitting error, the total uncertainty for Metis becomes 9x5x15 km. Concurrently, we find an EQJ2000 rotational pole at [RA; Dec]=[185° +19°] or in ecliptic coordinates, [λ ; β ]=[176° +20°] (ECJ2000).

  4. The Role of Triaxiality in Shape-Coexistence in Light Krypton Isotopes

    NASA Astrophysics Data System (ADS)

    Fischer, S. M.; Lister

    2008-04-01

    Shape co-existence in lead^1 and krypton^2-4 isotopes has become a cutting-edge topic in understanding the structure of heavier nuclei. Prediction of the relative binding energies of different shapes, and understanding the mixing between configurations presents a discriminating challenge to nuclear theory. In ^72,74,76Kr the occurrence of two well bound shapes has been demonstrated through the observation of low-lying J^π = 0^+ isomers and through radioactive beam Coulomb excitation. Roughly speaking, the shapes correspond to oblate-like and prolate-like configurations. However, the exact shapes, and the role of triaxiality has yet to be fully explored. We present new results from ``in-beam'' heavy-ion spectroscopy on ^74Kr which shows that the population of the isomer is mainly through a gamma vibrational band and that considerable mixing is involved between the states built on the isomer and the gamma band. This research was supported by the DOE Office of Nuclear Physics under contract DE-AC02-06CH11357. ^1A. N. Andreyev et al., Nature 405, 430 (2000) ^2E. Clement et al., Phys. Rev. C 75, 054313 (2007) ^3E. Bouchez et al., Phys. Rev. Lett. 90, 082502 (2003) ^4M. Bender et al., Phys. Rev. C 74, 024312 (2006)

  5. Fracture Angle Analysis of Rock Burst Faulting Planes Based on True-Triaxial Experiment

    NASA Astrophysics Data System (ADS)

    Gong, Weili; Peng, Yanyan; Wang, Hu; He, Manchao; Ribeiro e Sousa, L.; Wang, Jiong

    2015-05-01

    The aim of this paper is to estimate fracture angles in deep-seated rock bursts encountered in intact hard rock tunnels. The fracture angles of fault planes in rock burst failure are analytically formulated by employing stress analysis based on Mohr's circle construction. Mohr's circle construction suits well for representing the rock burst stress states including the static loading and dynamic unloading processes existing at or near the excavation surface. Four fracture angles can be precisely predicted using the proposed mathematical models, including two minimum angles for two conjugate planes where the shear stress is equal to the maximum static shear stress τ max while the normal stress approaches to zero, and two maximum angles for two conjugate planes where the normal stress is reduced from σ 1 to σ 1/2 while shear stress increases markedly from ±( σ 1- σ 3)/2 to the maximum dynamic shear τ dmax = ± σ 1/2. For validation of the analytical solutions to fracture angles, rock burst experiments on Laizhou granite were conducted using a modified true-triaxial apparatus. The predicted fracture angles are compared very well with the results obtained from the laboratory rock burst tests and are in good agreement with the in situ observations. The proposed solutions to the fracture angle are a function of the static stresses only which can be known a priori from a field survey.

  6. Triaxial rotor model description of E2 properties in {sup 186,188,190,192}Os

    SciTech Connect

    Allmond, J. M.; Zaballa, R.; Oros-Peusquens, A. M.; Kulp, W. D.; Wood, J. L.

    2008-07-15

    The triaxial rotor model with independent inertia and electric quadrupole tensors is applied to the description of the extensive set of E2 matrix elements available for {sup 186,188,190,192}Os. Most large and medium transition E2 matrix elements can be reproduced to within {approx}10%, and most diagonal elements to within {approx}30%. Most small transition matrix elements can be reproduced to within {approx}30%, and they support the interference effect exhibited by the model between the inertia and E2 tensors: this is a new feature of quantum rotor models. The diagonal E2 matrix elements at higher spins in the K=2 band are extremely sensitive to admixtures of higher K values: the low experimental values in {sup 190,192}Os indicate significant admixtures of K=4 components. Attention is given to the K{sup {pi}}=4{sup +} bands in these nuclei and the controversial issue of whether they are of quadrupole or hexadecapole nature.

  7. Mechanical behavior of a triaxially braided textile composite at high temperature

    NASA Astrophysics Data System (ADS)

    El Mourid, Amine

    The work presented in this thesis aimed at understanding the influence of viscoelasticity, temperature and aging on the mechanical behaviour of a textile composite using experimental, analytical and numerical tools. The studied material was a triaxially braided composite with fibres in the 0°/+/-60° directions. The yarns were made of carbon fibres, embedded in an MVK10 temperature resistant polyimide matrix. The first step consisted in developing analytical and numerical frameworks to predict viscoelastic behaviour in textile composites. Simulations were performed for both braided and woven textile architectures, at different stiffness contrasts and yarns volume fractions. The analytical framework accuracy was verified with the help of the numerical simulations. An important finding of this study was that the analytical framework, combined with the Mori-Tanaka model, leads to relatively accurate predictions for both the permanent and transient parts. Therefore, the authors believe that the Mori-Tanaka model with an adjusted aspect ratio to take into account yarn curvature is reliable for predicting viscoelastic behaviour in textile composites. The textile composite that was studied in this project did not display viscoelastic behaviour, due to the high yarn volume fraction. However, the framework remains relevant for higher temperature applications or lower yarn volume fractions. The second step was to investigate the temperature effect on the tensile behavior of the carbon/MVK10 triaxially braided composite material studied in this project. To achieve this goal, a series of room and high temperature tensile tests on both matrix and composite samples were performed. The tests on composite samples were performed along two different material directions at the maximum service temperature allowed by the Federal Aviation Administration for aircraft components, and a dedicated replication technique was developed in order to track crack densities as a function of

  8. Hierarchical classifier approach to physical activity recognition via wearable smartphone tri-axial accelerometer.

    PubMed

    Yusuf, Feridun; Maeder, Anthony; Basilakis, Jim

    2013-01-01

    Physical activity recognition has emerged as an active area of research which has drawn increasing interest from researchers in a variety of fields. It can support many different applications such as safety surveillance, fraud detection, and clinical management. Accelerometers have emerged as the most useful and extensive tool to capture and assess human physical activities in a continuous, unobtrusive and reliable manner. The need for objective physical activity data arises strongly in health related research. With the shift to a sedentary lifestyle, where work and leisure tend to be less physically demanding, research on the health effects of low physical activity has become a necessity. The increased availability of small, inexpensive components has led to the development of mobile devices such as smartphones, providing platforms for new opportunities in healthcare applications. In this study 3 subjects performed directed activity routines wearing a smartphone with a built in tri-axial accelerometer, attached on a belt around the waist. The data was collected to classify 11 basic physical activities such as sitting, lying, standing, walking, and the transitions in between them. A hierarchical classifier approach was utilised with Artificial Neural Networks integrated in a rule-based system, to classify the activities. Based on our evaluation, recognition accuracy of over 89.6% between subjects and over 91.5% within subject was achieved. These results show that activities such as these can be recognised with a high accuracy rate; hence the approach is promising for use in future work. PMID:23823307

  9. Extremely Low-Stress Triaxiality Tests in Calibration of Fracture Models in Metal-Cutting Simulation

    NASA Astrophysics Data System (ADS)

    Šebek, František; Kubík, Petr; Petruška, Jindřich; Hůlka, Jiří

    2016-04-01

    The cutting process is now combined with machining, milling, or drilling as one of the widespread manufacturing operations. It is used across various fields of engineering. From an economical point of view, it is desirable to maintain the process in the most effective way in terms of the fracture surface quality or minimizing the burr. It is not possible to manage this experimentally in mass production. Therefore, it is convenient to use numerical computation. To include the crack initiation and propagation in the computations, it is necessary to implement a suitable ductile fracture criterion. Uncoupled ductile fracture models need to be calibrated first from fracture tests when the test selection is crucial. In the present article, there were selected widespread uncoupled ductile fracture models calibrated with, among others, an extremely low-stress triaxiality test realized through the compression of a cylinder with a specific recess. The whole experimental program together with the cutting process experiment were carried out on AISI 1045 carbon steel. After the fracture models were calibrated and the cutting process was simulated with their use, fracture surfaces and force responses from computations were compared with those experimentally obtained and concluding remarks were made.

  10. Elastic anisotropy of Opalinus Clay under variable saturation and triaxial stress

    NASA Astrophysics Data System (ADS)

    Sarout, Joel; Esteban, Lionel; Delle Piane, Claudio; Maney, Bruce; Dewhurst, David N.

    2014-09-01

    A novel experimental method is introduced to estimate the Thomsen's elastic anisotropy parameters ɛ and δ of a transversely isotropic shale under variable stress and saturation conditions. The method consists in recording P-wave velocities along numerous paths on a cylindrical specimen using miniature ultrasonic transducers. Such an overdetermined set of measurements is specifically designed to reduce the uncertainty associated with the determination of Thomsen's δ parameter compared to the classical method for which a single off-axis measurement is used (usually at 45° to the specimen's axis). This method is applied to a specimen of Opalinus Clay recovered from the Mont-Terri Underground Research Laboratory in Switzerland. The specimen is first saturated with brine at low effective pressure and then subjected to an effective pressure cycle up to 40 MPa, followed by a triaxial loading up to failure. During saturation and deformation, the evolution of P-wave velocities along a maximum of 240 ray paths is monitored and Thomsen's parameters α, ɛ and δ are computed by fitting Thomsen's weak anisotropy model to the data. The values of ɛ and δ obtained at the highest confining pressures reached during the experiment are comparable with those predicted from X-ray diffraction texture analysis and modelling for Opalinus Clay reported in the literature. These models neglect the effect of soft-porosity on elastic properties, but become relevant when soft porosity is closed at high effective pressure.

  11. The triaxial particle plus rotor model and wobbling mode: A semiclassical view

    SciTech Connect

    Gupta, Rajiv; Malik, S. S.; Jain, A. K.; Jain, S. R.

    2010-11-24

    A systematic analysis of the triaxial particle rotor model with single-j shell configuration is carried out to explain the prominent features of observed wobbling excitations in odd A nuclei. The equations of motion for the angular momentum vectors I-vector and j-vector generate two types of equilibrium (i.e., (i) the axes aligned and (ii) the planar) states. The planar equilibrium states involve mainly the orientation degree of freedom {gamma} and their Jacobian matrix J gives purely imaginary eigenvalues in conjugate pairs. Also, our dynamical results show a substantial projection of angular momentum vectors on all the three principal axes, which implies that the resultant angular momentum lies outside the planes of three axes. Both these signatures confirm the spontaneous breakdown of time reversal (T) plus rotation by 180 deg. (R{sub {pi}}) i.e., R{sub {pi}T} symmetry and as a result nearly two identical bands consisting of even and odd spins emerge. We have tested our dynamical formalism for the wobbling mode observed in {sup 163}Lu.

  12. Tri-axial telecoil hearing aid for improved connection to public induction loops.

    PubMed

    Riehle, Timothy H; Knuesel, Robert J; Lichter, Patrick A; Panescu, Dorin

    2015-01-01

    Telecoils in hearing aids serve a dual purpose: to enhance telephone conversation and enable hearing aids to serve as a wireless interface for public audio broadcasts. When broadcasting audio signals, the signal is transmitted to the telecoil sensor (a magnetic field sensor located in the hearing aid) via magnetic energy from an induction wire loop located near the listener. This induction loop can be a small assembly located in the handset of the telephone or a large wire loop within a public venue like a theatre. Current hearing aids detect the magnetic signal using a single telecoil. If the telecoil is not aligned with the magnetic field, the strength of the detected signal is diminished. Unfortunately, public induction loops and telephone handsets seldom share a common alignment to the hearing aid, leading to sub-optimal performance by one or both in hearing aids available today. In this research, a prototype behind-the-ear (BTE) hearing aid with tri-axial telecoils was developed and DSP algorithms to process and combine the three signals were developed. The resulting hearing aid was evaluated in a human trial and provided better performance than a similar quality conventional telecoil hearing aid. PMID:26736209

  13. A new method of surface resistance measurement with a niobium triaxial cavity working at 2 K

    SciTech Connect

    Changnian Liang; H. Phillips; Ronald Sundelin

    1993-03-01

    A 1.5-GHz superconducting niobium triaxial cavity has been fabricated to study residual surface resistance of superconducting materials at 2 K. Unlike many other structures where the entire test samples have to be placed in strong magnetic field locations, we have the edge of a 25.4 mm or larger diameter sample outside of the strong field region, a procedure which will greatly reduce edge effects and image current losses between the thin film and substrate. A calorimetric method is used to measure the sample losses, and is designed to resolve a 10-{mu}K temperature change using 16 carbon resistor sensors. A detection limit of 0.05-{mu}W power dissipation has been determined with a calibration heater, which corresponds to a surface resistance of 0.02 n{Omega} at a maximum cavity magnetic field of 250 G. Initial cavity testing was performed in a magnetically unshielded cryostat, yielding a 2.2-{mu}{Omega} residual resistance which was measured by both the rf measurement and the calorimetric measurement.

  14. Effect of Microscopic Damage Events on Static and Ballistic Impact Strength of Triaxial Braid Composites

    NASA Technical Reports Server (NTRS)

    Littell, Justin D.; Binienda, Wieslaw K.; Arnold, William A.; Roberts, Gary D.; Goldberg, Robert K.

    2010-01-01

    The reliability of impact simulations for aircraft components made with triaxial-braided carbon-fiber composites is currently limited by inadequate material property data and lack of validated material models for analysis. Methods to characterize the material properties used in the analytical models from a systematically obtained set of test data are also lacking. A macroscopic finite element based analytical model to analyze the impact response of these materials has been developed. The stiffness and strength properties utilized in the material model are obtained from a set of quasi-static in-plane tension, compression and shear coupon level tests. Full-field optical strain measurement techniques are applied in the testing, and the results are used to help in characterizing the model. The unit cell of the braided composite is modeled as a series of shell elements, where each element is modeled as a laminated composite. The braided architecture can thus be approximated within the analytical model. The transient dynamic finite element code LS-DYNA is utilized to conduct the finite element simulations, and an internal LS-DYNA constitutive model is utilized in the analysis. Methods to obtain the stiffness and strength properties required by the constitutive model from the available test data are developed. Simulations of quasi-static coupon tests and impact tests of a represented braided composite are conducted. Overall, the developed method shows promise, but improvements that are needed in test and analysis methods for better predictive capability are examined.

  15. A laboratory study on the MSW mechanical behavior in triaxial apparatus.

    PubMed

    Karimpour-Fard, Mehran; Machado, Sandro Lemos; Shariatmadari, Nader; Noorzad, Ali

    2011-08-01

    Shear strength characterization of MSW materials is a mandatory task when performing analyses related to landfill design and landfill geometry improvements. Despite the considerable amount of research focusing on MSW mechanical behavior there remain certain aspects which are not completely understood and deserve attention in particular the case of the undrained behavior of MSW. This paper presents the results of a comprehensive laboratory testing program using a large-scale triaxial apparatus at the Federal University of Bahia, Salvador, Brazil. The effect of factors such as confining pressure, unit weight, fiber content, rate of loading and over-consolidation on the MSW mechanical response were investigated. Tested samples presented typical MSW shear/strain curves (concave upward) in all the tests, despite the pore water pressure reaching levels almost equal to the confining pressure. The obtained results show that increasing confining stress, unit weight, loading rate, fiber content and over-consolidation lead to an increase in the MSW shear strength. The importance of the fibrous components in the waste behavior is highlighted and graphs showing the variation of the MSW shear strength with fiber content in different drainage conditions are shown. The authors believe these results could be of interest to many companies, especially considering the new trend of plastic material recycling (prior landfilling) for energy recovery purposes. PMID:21478006

  16. Evaluation of Test Methods for Triaxially Braided Composites using a Meso-Scale Finite Element Model

    SciTech Connect

    Zhang, Chao

    2015-10-01

    The characterization of triaxially braided composite is complicate due to the nonuniformity of deformation within the unit cell as well as the possibility of the freeedge effect related to the large size of the unit cell. Extensive experimental investigation has been conducted to develop more accurate test approaches in characterizing the actual mechanical properties of the material we are studying. In this work, a meso-scale finite element model is utilized to simulate two complex specimens: notched tensile specimen and tube tensile specimen, which are designed to avoid the free-edge effect and free-edge effect induced premature edge damage. The full field strain data is predicted numerically and compared with experimental data obtained by Digit Image Correlation. The numerically predicted tensile strength values are compared with experimentally measured results. The discrepancy between numerically predicted and experimentally measured data, the capability of different test approaches are analyzed and discussed. The presented numerical model could serve as assistance to the evaluation of different test methods, and is especially useful in identifying potential local damage events.

  17. Effects of preform architecture on modulus and strength of 2-D triaxially braided textile composites

    NASA Technical Reports Server (NTRS)

    Masters, John E.; Naik, Rajiv; Minguet, Pierre J.

    1995-01-01

    Laminates formed using braided fibrous preforms have been extensively investigated during the course of the past few years as alternatives to unidirectional prepreg tape systems. This paper focused on one aspect of that work. It defined the role of the fibrous preform architecture in controlling a laminate's mechanical properties. The presentation was divided into four sections as the outline listed above illustrates. The presentation began with a brief introduction which defined the objectives of the study and detailed the materials studied. This was followed by a review of empirical test results. The materials' moduli and strengths were measured in both tension and compression. Their shear moduli were also experimentally determined. The review of the empirical data comprised the bulk of the presentation. A comparison of the experimental data to results predicted analytically was then presented. The presentation concluded with a few summary remarks. The specimens studied in this investigation featured 2-D triaxially braided AS4 graphite fiber preforms impregnated with Shell 1895 epoxy resin.

  18. Galaxy Formation in Triaxial Halos: Black Hole-Bulge-Dark Halo Correlation

    NASA Astrophysics Data System (ADS)

    El-Zant, Amr A.; Shlosman, Isaac; Begelman, Mitchell C.; Frank, Juhan

    2003-06-01

    The masses of supermassive black holes (SBHs) show correlations with bulge properties in disk and elliptical galaxies. We study the formation of galactic structure within flat-core, mildly triaxial halos and show that these correlations can be understood within the framework of a baryonic component modifying the orbital structure in the underlying potential. In particular, we find that terminal properties of bulges and their central SBHs are constrained by the destruction of box orbits in the harmonic cores of dark halos and the emergence of progressively less eccentric loop orbits there. SBH masses, M•, should exhibit a tighter correlation with bulge velocity dispersions, σB, than with bulge masses, MB, in accord with observations, if there is a significant scatter in the MH-σH relation for the halo. In the context of this model the observed M•-σB relation implies that halos should exhibit a Faber-Jackson type relationship between their masses and velocity dispersions. The most important prediction of our model is that halo properties determine the bulge and SBH parameters. The model also has important implications for galactic morphology and the process of disk formation.

  19. Spin-dependent γ softness or triaxiality in even-even 132-138Nd nuclei

    NASA Astrophysics Data System (ADS)

    Chai, Qing-Zhen; Wang, Hua-Lei; Yang, Qiong; Liu, Min-Liang

    2015-02-01

    The properties of γ instability in rapidly rotating even-even 132-138Nd isotopes have been investigated using the pairing-deformation self-consistent total-Routhian-surface calculations in a deformation space of (β2, γ, β4). It is found that even-even 134-138Nd nuclei exhibit triaxiality in both ground and excited states, even up to high-spin states. The lightest isotope possesses a well-deformed prolate shape without a γ deformation component. The current numerical results are compared with previous calculations and available observables such as quadrupole deformation β2 and the feature of γ-band levels, showing basically a general agreement with the observed trend of γ correlations (e.g. the pattern of the odd-even energy staggering of the γ band). The existing differences between theory and experiment are analyzed and discussed briefly. Supported by National Natural Science Foundation of China (10805040,11175217), Foundation and Advanced Technology Research Program of Henan Province(132300410125) and S & T Research Key Program of Henan Province Education Department (13A140667)

  20. PTM-SD: a database of structurally resolved and annotated posttranslational modifications in proteins

    PubMed Central

    Craveur, Pierrick; Rebehmed, Joseph; de Brevern, Alexandre G.

    2014-01-01

    Posttranslational modifications (PTMs) define covalent and chemical modifications of protein residues. They play important roles in modulating various biological functions. Current PTM databases contain important sequence annotations but do not provide informative 3D structural resource about these modifications. Posttranslational modification structural database (PTM-SD) provides access to structurally solved modified residues, which are experimentally annotated as PTMs. It combines different PTM information and annotation gathered from other databases, e.g. Protein DataBank for the protein structures and dbPTM and PTMCuration for fine sequence annotation. PTM-SD gives an accurate detection of PTMs in structural data. PTM-SD can be browsed by PDB id, UniProt accession number, organism and classic PTM annotation. Advanced queries can also be performed, i.e. detailed PTM annotations, amino acid type, secondary structure, SCOP class classification, PDB chain length and number of PTMs by chain. Statistics and analyses can be computed on a selected dataset of PTMs. Each PTM entry is detailed in a dedicated page with information on the protein sequence, local conformation with secondary structure and Protein Blocks. PTM-SD gives valuable information on observed PTMs in protein 3D structure, which is of great interest for studying sequence–structure– function relationships at the light of PTMs, and could provide insights for comparative modeling and PTM predictions protocols. Database URL: PTM-SD can be accessed at http://www.dsimb.inserm.fr/dsimb_tools/PTM-SD/. PMID:24857970

  1. SdPI, The First Functionally Characterized Kunitz-Type Trypsin Inhibitor from Scorpion Venom

    PubMed Central

    Li, Tian; He, Yawen; Ma, Yibao; Chen, Zongyun; Wu, Yingliang; Li, Wenxin; Cao, Zhijian

    2011-01-01

    Background Kunitz-type venom peptides have been isolated from a wide variety of venomous animals. They usually have protease inhibitory activity or potassium channel blocking activity, which by virtue of the effects on predator animals are essential for the survival of venomous animals. However, no Kunitz-type peptides from scorpion venom have been functionally characterized. Principal Findings A new Kunitz-type venom peptide gene precursor, SdPI, was cloned and characterized from a venom gland cDNA library of the scorpion Lychas mucronatus. It codes for a signal peptide of 21 residues and a mature peptide of 59 residues. The mature SdPI peptide possesses a unique cysteine framework reticulated by three disulfide bridges, different from all reported Kunitz-type proteins. The recombinant SdPI peptide was functionally expressed. It showed trypsin inhibitory activity with high potency (Ki = 1.6×10−7 M) and thermostability. Conclusions The results illustrated that SdPI is a potent and stable serine protease inhibitor. Further mutagenesis and molecular dynamics simulation revealed that SdPI possesses a serine protease inhibitory active site similar to other Kunitz-type venom peptides. To our knowledge, SdPI is the first functionally characterized Kunitz-type trypsin inhibitor derived from scorpion venom, and it represents a new class of Kunitz-type venom peptides. PMID:22087336

  2. THE SAGITTARIUS DWARF GALAXY: A MODEL FOR EVOLUTION IN A TRIAXIAL MILKY WAY HALO

    SciTech Connect

    Law, David R.; Majewski, Steven R. E-mail: srm4n@virginia.ed

    2010-05-01

    We present a new N-body model for the tidal disruption of the Sagittarius (Sgr) dwarf that is capable of simultaneously satisfying the majority of angular position, distance, and radial velocity constraints imposed by current wide-field surveys of its dynamically young ({approx_lt}3 Gyr) tidal debris streams. In particular, this model resolves the conflicting angular position and radial velocity constraints on the Sgr leading tidal stream that have been highlighted in recent years. While the model does not reproduce the apparent bifurcation observed in the leading debris stream, recent observational data suggest that this bifurcation may represent a constraint on the internal properties of the Sgr dwarf rather than the details of its orbit. The key element in the success of this model is the introduction of a non-axisymmetric component to the Galactic gravitational potential that can be described in terms of a triaxial dark matter halo whose minor/major axis ratio (c/a){sub {Phi}} = 0.72 and intermediate/major axis ratio (b/a){sub {Phi}} = 0.99 at radii 20 kpc < r < 60 kpc. The minor/intermediate/major axes of this halo lie along the directions (l, b) = (7{sup 0}, 0{sup 0}), (0{sup 0}, 90{sup 0}), and (97{sup 0}, 0{sup 0}) respectively, corresponding to a nearly oblate ellipsoid whose minor axis is contained within the Galactic disk plane. This particular disk/halo orientation is difficult to reconcile within the general context of galactic dynamics (and cold dark matter models in particular), suggesting either that the orientation may have evolved significantly with time or that inclusion of other non-axisymmetric components (such as the gravitational influence of the Magellanic Clouds) in the model may obviate the need for triaxiality in the dark matter halo. The apparent proper motion of Sgr in this model is estimated to be ({mu}{sub l}cos b, {mu}{sub b}) = (-2.16, 1.73) mas yr{sup -1}, corresponding to a Galactocentric space velocity (U, V, W) = (230, -35, 195

  3. Hydromechanical Behaviour of Unconsolidated Granular Materials under Proportional Triaxial Compression Tests

    NASA Astrophysics Data System (ADS)

    Nguyen, V.; Gland, N. F.; Dautriat, J.; Guelard, J.; David, C.

    2010-12-01

    During the production of petroleum reservoirs, compaction due to depletion (pore fluid pressure reduction) can lead to emphasis of natural permeability anisotropy and significant permeability reduction. Under such effective stress increase, weakly consolidated reservoirs will undergo strong deformation inducing important modifications of the transport properties, which control the fluid flows in the reservoir and the productivity of the wells. Classically the mechanical loadings applied in the laboratory are either hydrostatic or deviatoric at constant confining pressure; however the 'in-situ' stress paths experienced by the reservoirs differ; it is thus important to perform loading tests with more appropriate conditions such as ‘proportional triaxial’ and ‘oedometric’. This study focuses on the elastoplatic behaviour of non to weakly consolidated reservoir rocks (analogues) and the influence of the stress path (K=ΔσH/ΔσV) on the evolutions of porosity and permeability. Generally, permeability of pourous rocks evolves in three stages: (1) initial decrease related to compaction (soft rocks) or closing of pre-existing microflaws (compact rocks), (2) small reduction associated to the 'linear' deformation regime, (3) drop due to a strong compaction linked to porosity collapse and grain crushing mechanisms. The intensity of this reduction depends on the stress path coefficient, the grain sharpness and the granular texture. We use a triaxial cell (maximum axial load of 80kN and maximum confinement of 69MPa) to perform proportional triaxial compression tests (0

  4. Assessing head and trunk symmetry during sleep using tri-axial accelerometers.

    PubMed

    Sato, Haruhiko; Ikura, Daiki; Tsunoda, Masahiro

    2015-03-01

    Using two types of small, lightweight tri-axial accelerometers, we obtained evidence for the effectiveness of an approach for assessing head-trunk symmetrical or asymmetrical positions during sleep. First, we assessed the accuracy of our monitoring system in five healthy young adults (age range, 22-24 years). The participants wore acceleration monitors on the sternum and forehead; then spent 5 min in six different positions. Once accuracy was confirmed, we assessed head-trunk symmetry during night-time sleep in 10 healthy children (age range, 3-13 years) and 10 young adults (age range, 21-26 years) in their home environments. All participants wore the monitors during one night's sleep in their homes. After computing head-trunk positions using the orientation data obtained by the accelerometers, head and trunk symmetry were evaluated. The head and trunk positions were correctly detected: the positional data from the trunk had 99% agreement, and the data from the head had 96% agreement. Both the young adults and children were observed to spend time with the head-trunk in asymmetric positions; however, the subjects changed position frequently so the asymmetrical postures were mobile. We concluded that the proposed monitoring system is a reliable and valid approach for assessing head-trunk symmetry during sleep at home. Implications for Rehabilitation We propose a head and trunk symmetry monitoring system using accelerometers. The proposed system could accurately identify head and trunk position. Asymmetrical positioning was seen in healthy participants but it was not immobile. PMID:24274623

  5. Structure Formation inside Triaxial Dark Matter Halos: Galactic Disks, Bulges, and Bars

    NASA Astrophysics Data System (ADS)

    Heller, Clayton H.; Shlosman, Isaac; Athanassoula, E.

    2007-12-01

    We investigate formation and evolution of galactic disks immersed in assembling live DM halos. Models have been evolved from cosmological initial conditions and represent the collapse of an isolated density perturbation. The baryons include gas participating in star formation (SF) and stars with the energy feedback onto the ISM. We find that (1) the triaxial halo figure tumbling is insignificant and the angular momentum (J) is channeled into the internal circulation, while the baryonic collapse is stopped by the centrifugal barrier; (2) density response of the (disk) baryons is out of phase with DM, thus washing out the inner halo ellipticity; (3) the total J is neatly conserved, even in models accounting for stellar feedback; (4) the specific J for DM is nearly constant, while that for baryons is decreasing; (5) early stage of disk formation resembles the cat's cradle-a small amorphous disk fueled via radial string patterns-followed by growing oval disk whose shape varies with its orientation to the halo major axis; (6) the disk gas layer thins when the SF rate drops below ~5 Msolar yr-1 (7) about half of the baryons remain outside the disk SF region or in the halo as a hot gas; (8) rotation curves appear to be flat and account for the observed disk/halo contributions; (9) a range of bulge-dominated to bulgeless disks was obtained, depending on the stellar feedback parameter, ɛSF: smaller ɛSF leads to a larger and earlier bulge; lower density threshold for SF leads to a smaller, thicker disk; gas gravitational softening mimics a number of intrinsic processes within the ISM; (10) models are characterized by an extensive bar-forming activity; (11) nested bars form in response to the gas inflow along the primary bars, as shown by Heller, Shlosman, and Athanassoula.

  6. Tri-axial Shape Coexistence and a New Aligned Band in 178Os

    NASA Astrophysics Data System (ADS)

    Govil, I. M.

    2009-03-01

    The Os nuclei lie in the beginning of the transitional region between the well deformed rare earth and spherical lead isotopes. The nuclei in this region are believed to be soft to changes in gamma deformation due to the softness of nuclear potential which may result in the shape coexistence. The neutron Fermi levels in Os nuclei from A = 170 to A = 186 lie in the middle of i13/2 orbital so that their shape in the ground state tends to take an appreciable prolate deformation. Hence collective bands with the well defined moment of inertia occur and the effect of different proton orbitals is observed as a modulation of the prolate structure. The anomalies in the yrast sequence, an effect attributed to change in moment of inertia of the ground state rotational band and the band crossing phenomena, are very important and vary strongly with neutron number in case of Os nuclei. The nuclear structure of 178Os nucleus has been studied using the reaction 165Ho (20Ne, p6n) 178Os. Indian National Gamma Array (INGA) consisting of six Clover detectors with anti Compton shields was used for the detection of resulting gamma rays. The Direction Correlation of γ-rays de-exciting Oriented states (DCO) ratio and polarization of gamma rays were measured to assign spin, parity and multipolarity of transitions. Twenty one new transitions belonging to the 178Os nucleus have been identified. The sudden and rather strong gain in aligned angular momentum is observed in the yrast band of 178Os. A new aligned rotational band similar to 180Os is also discovered in this nucleus. This band exhibits a very complex decay pattern with a single linking transition of 1778 keV to the ground state band. The tri-axial shape co-existence is also observed in this nucleus at higher excitation. The experimental results are compared with the Microscopic Hartree-Fock model calculations.

  7. Distinguishing the causes of falls in humans using an array of wearable tri-axial accelerometers.

    PubMed

    Aziz, Omar; Park, Edward J; Mori, Greg; Robinovitch, Stephen N

    2014-01-01

    Falls are the number one cause of injury in older adults. Lack of objective evidence on the cause and circumstances of falls is often a barrier to effective prevention strategies. Previous studies have established the ability of wearable miniature inertial sensors (accelerometers and gyroscopes) to automatically detect falls, for the purpose of delivering medical assistance. In the current study, we extend the applications of this technology, by developing and evaluating the accuracy of wearable sensor systems for determining the cause of falls. Twelve young adults participated in experimental trials involving falls due to seven causes: slips, trips, fainting, and incorrect shifting/transfer of body weight while sitting down, standing up from sitting, reaching and turning. Features (means and variances) of acceleration data acquired from four tri-axial accelerometers during the falling trials were input to a linear discriminant analysis technique. Data from an array of three sensors (left ankle+right ankle+sternum) provided at least 83% sensitivity and 89% specificity in classifying falls due to slips, trips, and incorrect shift of body weight during sitting, reaching and turning. Classification of falls due to fainting and incorrect shift during rising was less successful across all sensor combinations. Furthermore, similar classification accuracy was observed with data from wearable sensors and a video-based motion analysis system. These results establish a basis for the development of sensor-based fall monitoring systems that provide information on the cause and circumstances of falls, to direct fall prevention strategies at a patient or population level. PMID:24148648

  8. Investigation on Mechanical Behaviors of Sandstone with Two Preexisting Flaws under Triaxial Compression

    NASA Astrophysics Data System (ADS)

    Huang, Da; Gu, Dongming; Yang, Chao; Huang, Runqiu; Fu, Guoyang

    2016-02-01

    Triaxial compression experiments on sandstone samples with two preexisting closed non-overlapping flaws were performed to investigate the deformation and strength behaviors. Three types of preexisting closed flaw pair in sandstone samples, i.e., parallel low-dip (type B), parallel high-dip (type C), and composite high- and low-dip (type D), were considered as the typical arrangements of the non-overlapping crack pair. A general rule has been found that the arrangement of the flaw pair has greater impact on the rock deformation, strength, and crack coalescence pattern than the confining pressure (5-20 MPa). Experimental results showed that, compared with intact sandstone samples, the postpeak stress-strain curves of flawed samples distinctly demonstrate stress fluctuation. In particular, the unique prepeak stress-strain curves of the specimens with a low-dip flaw pair (type B) present oblique Z-shape with a double-peak stress. The stress for crack initiation σ ci, the critical stress of dilation σ cd, and the peak strength σ c of precracked sandstone samples are significantly lower than those of intact rock. The present numerical study, which is an extension of the test analysis, focuses on identifying the crack nature (tensile or shear) and coalescence process. These simulated crack coalescence patterns are in good agreement with the laboratory test results. The cracks of the precracked samples that contained flaws with small inclination angle (associated with either type B or type D) generally initiate at the inner flaw tips and eventually lead to simple direct shear coalescence. However, complex indirect shear coalescence appears in the model containing a steep preexisting flaw pair (associated with type B specimen), even though no coalescence occurs when σ 3 = 5 MPa.

  9. In-shoe plantar tri-axial stress profiles during maximum-effort cutting maneuvers.

    PubMed

    Cong, Yan; Lam, Wing Kai; Cheung, Jason Tak-Man; Zhang, Ming

    2014-12-18

    Soft tissue injuries, such as anterior cruciate ligament rupture, ankle sprain and foot skin problems, frequently occur during cutting maneuvers. These injuries are often regarded as associated with abnormal joint torque and interfacial friction caused by excessive external and in-shoe shear forces. This study simultaneously investigated the dynamic in-shoe localized plantar pressure and shear stress during lateral shuffling and 45° sidestep cutting maneuvers. Tri-axial force transducers were affixed at the first and second metatarsal heads, lateral forefoot, and heel regions in the midsole of a basketball shoe. Seventeen basketball players executed both cutting maneuvers with maximum efforts. Lateral shuffling cutting had a larger mediolateral braking force than 45° sidestep cutting. This large braking force was concentrated at the first metatarsal head, as indicated by its maximum medial shear stress (312.2 ± 157.0 kPa). During propulsion phase, peak shear stress occurred at the second metatarsal head (271.3 ± 124.3 kPa). Compared with lateral shuffling cutting, 45° sidestep cutting produced larger peak propulsion shear stress (463.0 ± 272.6 kPa) but smaller peak braking shear stress (184.8 ± 181.7 kPa), of which both were found at the first metatarsal head. During both cutting maneuvers, maximum medial and posterior shear stress occurred at the first metatarsal head, whereas maximum pressure occurred at the second metatarsal head. The first and second metatarsal heads sustained relatively high pressure and shear stress and were expected to be susceptible to plantar tissue discomfort or injury. Due to different stress distribution, distinct pressure and shear cushioning mechanisms in basketball footwear might be considered over different foot regions. PMID:25468303

  10. Fractal characteristics and acoustic emission of coal containing methane in triaxial compression failure

    NASA Astrophysics Data System (ADS)

    Kong, Xiangguo; Wang, Enyuan; Hu, Shaobin; Shen, Rongxi; Li, Xuelong; Zhan, Tangqi

    2016-01-01

    Aimed at exploring the influence of methane to coal and studying fractal characteristics and acoustic emission (AE) features in the damage evolution, the triaxial compression experiments of coal containing methane were conducted, and acoustic emission response was collected simultaneously in the loading process. Based on the method for calculating the correlation dimension, the fractal dimension was calculated with regard to time series of acoustic emission. Our experimental results indicate that AE response and fractal dimension can reflect the evolution and propagation of cracks in the loading process. Corresponding to the load-time, acoustic emission experiences active, linearly increasing, rapidly augmenting and decreasing stage. However, the fractal dimension of AE develops from chaos to orderly state. Late loading, a continued slowdown in fractal dimension, can be used as a precursory signal of coal sample destruction. In addition, the amount of gas in the coal sample will influence the evolution of pore and fracture, which causes a variation in the acoustic emission signals and fractal dimension. The maximum bearing load reduces 18.85% and 49.18% within pore pressure of 0.75 and 1.5 MPa, compared with it (24.4 kN) of the coal sample (without gas). What's more, the increase of pore pressure will cause the growth of AE count and energy, but the correlation dimension of AE parameters drops. This study is helpful for us to understand the effects of methane to coal and the evolution mechanism of cracks, and it can be applied to the research on occurrence mechanism and early warning of coal and gas outburst.

  11. Characterization of MODIS SD screen vignetting function using observations from spacecraft yaw maneuvers

    NASA Astrophysics Data System (ADS)

    Wang, Zhipeng; Xiong, Xiaoxiong

    2009-08-01

    The MODIS reflective solar bands (RSB) include both the low-gain and high-gain spectral bands depending on their specific applications. MODIS RSBs are calibrated on-orbit by an on-board solar diffuser. In order to avoid detector response saturation when calibrating the high-gain bands, an optional attenuation screen, made of a metal plate with pinhole arrays, is placed in front of the SD panel. Since no pre-launch system-level characterization was made for the SD screen (SDS) vignetting function (VF), a series of spacecraft (Terra and Aqua) yaw maneuvers were carried out to perform on-orbit characterization of the VF. Assuming that the low-gain bands and the high-gain bands have the same VF, the current VF was derived from yaw observations using the MODIS low-gain bands through taking the ratio of their SD responses with and without the SDS in place. In this study, we attempt to characterize the SDS VF directly using detector responses of individual high-gain bands with the SDS in place only. The corresponding SD responses without the SDS, not available from measurements due to saturation, are calculated using detector gains, the SD bi-directional reflectance factor (BRF), and the view geometry that matches the yaw observations with the SDS in place. Results and discussions are focused on the band dependent and detector dependent features of the SDS VF, and their potential impact on the RSB calibration.

  12. The qSD12 Locus Controls Offspring Tissue-Imposed Seed Dormancy in Rice

    PubMed Central

    Gu, Xing-You; Turnipseed, E. Brent; Foley, Michael E.

    2008-01-01

    Seed component structures were grouped into maternal and offspring (embryo and endosperm) tissues to characterize a dormancy quantitative trait locus (QTL) for tissue-specific function using a marker-assisted genetic approach. The approach was devised to test if genotypic/allelic frequencies of a marker tightly linked to the QTL deviate from Mendelian expectations in germinated and nongerminated subpopulations derived from a segregation population of partially after-ripened seeds and was applied to the dormancy QTL qSD12 and qSD7-1 in a nearly isogenic background of rice. Experimental results unambiguously demonstrated that qSD12 functions in the offspring tissue(s) and suggested that qSD7-1 may control dormancy through the maternal tissues. These experiments also provide the first solid evidence that an offspring tissue-imposed dormancy gene contributes to the segregation distortion in a mapping population developed from partially after-ripened seeds and, in part, to the germination heterogeneity of seeds from hybrid plants. Offspring and maternal tissue-imposed dormancy genes express in very early and late stages of the life cycle, respectively, and interact to provide the species with complementary adaptation strategies. The qSD12 locus was narrowed to the region of ∼600 kbp on a high-resolution map to facilitate cloning and marker-assisted selection of the major dormancy gene. PMID:18711220

  13. The Mass of the sdB Primary of the Binary HS 2333+3927

    NASA Astrophysics Data System (ADS)

    Heber, U.; Drechsel, H.; Karl, C.; Østensen, R.; Folkes, S.; Napiwotzki, R.; Altmann, M.; Cordes, O.; Solheim, J.-E.; Voss, B.; Koester, D.

    2005-07-01

    Short period sdB binaries with cool companions are crucial to understand pre-CV evolution, because they will evolve into cataclysmic variables, when the sdB will have left the extended horizontal branch. Recently we discovered the sixth such system, HS 2333+3927, consisting of an sdB star and an M dwarf (period: 0.172 d) with a very strong reflection effect, but no eclipses. The reflection is stronger than in any of the other similar systems which renders a quantitative spectral analysis very difficult because the Balmer line profiles may be disturbed by the reflected light. A spectroscopic analysis results in {Teff} = 36 500 K, log{g} = 5.70, and log (nHe/nH) = -2.15. Mass-radius relations were derived from the results of the analysis of light and radial-velocity curves. Comparison with the mass-radius relation derived from the surface gravity of the sdB star favours a rather low mass of 0.38 M⊙ for the primary. The mass of the companion is 0.29 M⊙. HS 2333+3927 is the only known sdB+dM system with a period above the CV period gap.

  14. Hypertension during chronic exposure to cold: Comparison between Sprague Dawley (SD) and Long Evans (LE) strains

    SciTech Connect

    Riesselmann, A.; Baron, A.; Fregly, M.J. )

    1991-03-11

    Hypertension accompanies chronic exposure of SD rats to cold (5-6C), including elevation of systolic, diastolic, and mean blood pressures and cardiac hypertrophy. The renin-angiotensin system may play an important role. Earlier studies suggested that the LE strain may have a decrease in angiotensin I converting enzyme (ACE) activity. Measurement of ACE activity in plasmas of SE and LE strains revealed that basal activity of ACE in the plasma of the LE strain was significantly less than that of the SD strain. A second study was carried out in which both strains were exposed to cold for 7 weeks. There were clear differences between strains. Rats of the SD strain had a significant elevation in their blood pressure; a significantly increased urinary output of norepinephrine (NE) and epinephrine (E); and significant increases in weights of heart, kidneys, adrenals, and brown adipose tissue (IBAT) compared to their controls maintained at 26C. In contrast, rats of the LE strain were less responsive to cold in that blood pressure failed to rise as sharply and to attain as high a level; NE and E outputs, as well as weights of heart and IBAT were significantly less than those of rats of the cold-treated SD strain. Thus, the lower ACE activity in plasma of LE strain, as well as a reduced secretion of catecholamines, may protect these rats against the rise of blood pressure characteristically observed when rats of the SD strain are exposed to cold.

  15. Wireless Tri-Axial Trunk Accelerometry Detects Deviations in Dynamic Center of Mass Motion Due to Running-Induced Fatigue

    PubMed Central

    2015-01-01

    Small wireless trunk accelerometers have become a popular approach to unobtrusively quantify human locomotion and provide insights into both gait rehabilitation and sports performance. However, limited evidence exists as to which trunk accelerometry measures are suitable for the purpose of detecting movement compensations while running, and specifically in response to fatigue. The aim of this study was therefore to detect deviations in the dynamic center of mass (CoM) motion due to running-induced fatigue using tri-axial trunk accelerometry. Twenty runners aged 18–25 years completed an indoor treadmill running protocol to volitional exhaustion at speeds equivalent to their 3.2 km time trial performance. The following dependent measures were extracted from tri-axial trunk accelerations of 20 running steps before and after the treadmill fatigue protocol: the tri-axial ratio of acceleration root mean square (RMS) to the resultant vector RMS, step and stride regularity (autocorrelation procedure), and sample entropy. Running-induced fatigue increased mediolateral and anteroposterior ratios of acceleration RMS (p < .05), decreased the anteroposterior step regularity (p < .05), and increased the anteroposterior sample entropy (p < .05) of trunk accelerometry patterns. Our findings indicate that treadmill running-induced fatigue might reveal itself in a greater contribution of variability in horizontal plane trunk accelerations, with anteroposterior trunk accelerations that are less regular from step-to-step and are less predictable. It appears that trunk accelerometry parameters can be used to detect deviations in dynamic CoM motion induced by treadmill running fatigue, yet it is unknown how robust or generalizable these parameters are to outdoor running environments. PMID:26517261

  16. A wearable force plate system for the continuous measurement of triaxial ground reaction force in biomechanical applications

    NASA Astrophysics Data System (ADS)

    Liu, Tao; Inoue, Yoshio; Shibata, Kyoko

    2010-08-01

    The ambulatory measurement of ground reaction force (GRF) and human motion under free-living conditions is convenient, inexpensive and never restricted to gait analysis in a laboratory environment and is therefore much desired by researchers and clinical doctors in biomedical applications. A wearable force plate system was developed by integrating small triaxial force sensors and three-dimensional (3D) inertial sensors for estimating dynamic triaxial GRF in biomechanical applications. The system, in comparison to existent systems, is characterized by being lightweight, thin and easy-to-wear. A six-axial force sensor (Nitta Co., Japan) was used as a verification measurement device to validate the static accuracy of the developed force plate. To evaluate the precision during dynamic gait measurements, we compared the measurements of the triaxial GRF and the center of pressure (CoP) by using the developed system with the reference measurements made using a stationary force plate and an optical motion analysis system. The root mean square (RMS) differences of the two transverse components (x- and y-axes) and the vertical component (z-axis) of the GRF were 4.3 ± 0.9 N, 6.0 ± 1.3 N and 12.1 ± 1.1 N, respectively, corresponding to 5.1 ± 1.1% and 6.5 ± 1% of the maximum of each transverse component and 1.3 ± 0.2% of the maximum vertical component of GRF. The RMS distance between the two systems' CoP traces was 3.2 ± 0.8 mm, corresponding to 1.2 ± 0.3% of the length of the shoe. Moreover, based on the results of the assessment of the influence of the system on natural gait, we found that gait was almost never affected. Therefore, the wearable system as an alternative device can be a potential solution for measuring CoP and triaxial GRF in non-laboratory environments.

  17. New O(6) region near A = 130 and the interplay of triaxiality and gamma-softness in the IBA

    SciTech Connect

    Casten, R.F.

    1984-01-01

    A simple approach to the IBA is described, which exploits the consistent Q-formalism to describe both symmetries and transition regions with a minimum of parameters. Some results with this approach are discussed and compared with the data for deformed and transitional nuclei. Following this introduction, a new region of O(6) symmetry is presented and compared with the Pt region with which it is found to share many similarities. Discrepancies with the strict limiting symmetry are described in terms of symmetry breaking via a small triaxial potential. 28 refs., 15 figs.

  18. Evolution from spherical single-particle structure to stable triaxiality at high spins in {sup 140}Nd

    SciTech Connect

    Petrache, C.M.; Fantuzi, M.; LoBianco, G.; Mengoni, D.; Neusser-Neffgen, A.; Huebel, H.; Al-Khatib, A.; Bringel, P.; Buerger, A.; Nenoff, N.; Schoenwasser, G.; Singh, A.K.; Ragnarsson, I.; Hagemann, G.B.; Herskind, B.; Jensen, D.R.; Sletten, G.; Fallon, P.; Goergen, A.; Bednarczyk, P.

    2005-12-15

    The level structure of {sub 60}{sup 140}Nd{sub 80} has been established up to spin 48 by in-beam {gamma}-ray spectroscopy by use of the {sup 96}Zr({sup 48}Ca, 4n) reaction. High-fold {gamma}-ray coincidences were measured with the EUROBALL spectrometer. Twelve new rotational bands have been discovered at high spins. They are interpreted as being formed in a deep triaxial minimum at {epsilon}{sub 2}{approx_equal}0.25 and {gamma}{approx_equal}35 deg. Possible configurations are assigned to the observed bands on the basis of configuration-dependent cranked Nilsson-Strutinsky calculations.

  19. Geobacter sp. SD-1 with enhanced electrochemical activity in high-salt concentration solutions.

    PubMed

    Sun, Dan; Call, Douglas; Wang, Aijie; Cheng, Shaoan; Logan, Bruce E

    2014-12-01

    An isolate, designated strain SD-1, was obtained from a biofilm dominated by Geobacter sulfurreducens in a microbial fuel cell. The electrochemical activity of strain SD-1 was compared with type strains, G. sulfurreducens PCA and Geobacter metallireducens GS-15, and a mixed culture in microbial electrolysis cells. SD-1 produced a maximum current density of 290 ± 29 A m−3 in a high-concentration phosphate buffer solution (PBS-H, 200 mM). This current density was significantly higher than that produced by the mixed culture (189 ± 44 A m−3) or the type strains (< 70 A m−3). In a highly saline water (SW; 50 mM PBS and 650 mM NaCl), current by SD-1 (158 ± 4 A m−3) was reduced by 28% compared with 50 mM PBS (220 ± 4 A m−3), but it was still higher than that of the mixed culture (147 ± 19 A m−3), and strains PCA and GS-15 did not produce any current. Electrochemical tests showed that the improved performance of SD-1 was due to its lower charge transfer resistance and more negative potentials produced at higher current densities. These results show that the electrochemical activity of SD-1 was significantly different than other Geobacter strains and mixed cultures in terms of its salt tolerance. PMID:25756125

  20. A New sdO+dM Binary with Extreme Eclipses and Reflection Effect

    NASA Astrophysics Data System (ADS)

    Derekas, A.; Németh, P.; Southworth, J.; Borkovits, T.; Sárneczky, K.; Pál, A.; Csák, B.; Garcia-Alvarez, D.; Maxted, P. F. L.; Kiss, L. L.; Vida, K.; Szabó, Gy. M.; Kriskovics, L.

    2015-08-01

    We report the discovery of a new totally eclipsing binary (R.A. = {06}{{h}}{40}{{m}}{29}{{s}}11; decl. = +38°56‧52″2 J = 2000.0; Rmax = 17.2 mag) with an sdO primary and a strongly irradiated red dwarf companion. It has an orbital period of Porb = 0.187284394(11) day and an optical eclipse depth in excess of 5 mag. We obtained 2 low-resolution classification spectra with GTC/OSIRIS and 10 medium-resolution spectra with WHT/ISIS to constrain the properties of the binary members. The spectra are dominated by H Balmer and He ii absorption lines from the sdO star, and phase-dependent emission lines from the irradiated companion. A combined spectroscopic and light curve analysis implies a hot subdwarf temperature of Teff(spec) = 55,000 ± 3000 K, surface gravity of log g (phot) = 6.2 ± 0.04 (cgs), and a He abundance of {log}(n{He}/n{{H}})=-2.24+/- 0.40. The hot sdO star irradiates the red dwarf companion, heating its substellar point to about 22,500 K. Surface parameters for the companion are difficult to constrain from the currently available data: the most remarkable features are the strong H Balmer and C ii-iii lines in emission. Radial velocity estimates are consistent with the sdO+dM classification. The photometric data do not show any indication of sdO pulsations with amplitudes greater than 7 mmag, and Hα-filter images do not provide evidence for the presence of a planetary nebula associated with the sdO star.

  1. Shell-model study for neutron-rich sd-shell nuclei

    SciTech Connect

    Kaneko, Kazunari; Sun Yang; Mizusaki, Takahiro; Hasegawa, Munetake

    2011-01-15

    The microscopic structure of neutron-rich sd-shell nuclei is investigated by using the spherical-shell model in the sd-pf valence space with the extended pairing plus quadrupole-quadrupole forces accompanied by the monopole interaction (EPQQM). The calculation reproduces systematically the known energy levels for even-even and odd-mass nuclei including the recent data for {sup 43}S, {sup 46}S, and {sup 47}Ar. In particular, the erosion of the N=28 shell closure in {sup 42}Si can be explained. Our EPQQM results are compared with other shell-model calculations with the SDPF-NR and SDPF-U effective interactions.

  2. Epoxy encapsulation of the Cernox™ SD thermometer for measuring the temperature of surfaces in liquid helium

    NASA Astrophysics Data System (ADS)

    Dhuley, R. C.; Van Sciver, S. W.

    2016-07-01

    We describe a procedure to pot a Cernox™ thermometer with the SD package in Stycast epoxy. The potting adapts the thermometer for measuring the temperature of a surface immersed in liquid helium (LHe) and other cryogens. The technique thermally insulates the sensor chip from the cryogen while preserving the surface mounting capability of the SD package. The potting introduced <1% shift in the resistance, <0.5% shift in the calibration at 4.2 K and 77 K, and provided repeatable measurements during thermal cycles between room temperature and 4.2 K.

  3. Initial results from the Solar Dynamic (SD) Ground Test Demonstration (GTD) project at NASA Lewis

    NASA Technical Reports Server (NTRS)

    Shaltens, Richard K.; Boyle, Robert V.

    1995-01-01

    A government/industry team designed, built, and tested a 2 kWe solar dynamic space power system in a large thermal/vacuum facility with a simulated sun at the NASA Lewis Research Center. The Lewis facility provides an accurate simulation of temperatures, high vacuum, and solar flux as encountered in low earth orbit. This paper reviews the goals and status of the Solar Dynamic (SD) Ground Test Demonstration (GTD) program and describes the initial testing, including both operational and performance data. This SD technology has the potential as a future power source for the International Space Station Alpha.

  4. Tri-axial Shape Coexistence and a New Aligned Band in {sup 178}Os

    SciTech Connect

    Govil, I. M.

    2009-03-10

    The Os nuclei lie in the beginning of the transitional region between the well deformed rare earth and spherical lead isotopes. The nuclei in this region are believed to be soft to changes in gamma deformation due to the softness of nuclear potential which may result in the shape coexistence. The neutron Fermi levels in Os nuclei from A = 170 to A = 186 lie in the middle of i{sub 13/2} orbital so that their shape in the ground state tends to take an appreciable prolate deformation. Hence collective bands with the well defined moment of inertia occur and the effect of different proton orbitals is observed as a modulation of the prolate structure. The anomalies in the yrast sequence, an effect attributed to change in moment of inertia of the ground state rotational band and the band crossing phenomena, are very important and vary strongly with neutron number in case of Os nuclei. The nuclear structure of {sup 178}Os nucleus has been studied using the reaction {sup 165}Ho({sup 20}Ne, p6n){sup 178}Os. Indian National Gamma Array (INGA) consisting of six Clover detectors with anti Compton shields was used for the detection of resulting gamma rays. The Direction Correlation of {gamma}-rays de-exciting Oriented states (DCO) ratio and polarization of gamma rays were measured to assign spin, parity and multipolarity of transitions. Twenty one new transitions belonging to the {sup 178}Os nucleus have been identified. The sudden and rather strong gain in aligned angular momentum is observed in the yrast band of {sup 178}Os. A new aligned rotational band similar to {sup 180}Os is also discovered in this nucleus. This band exhibits a very complex decay pattern with a single linking transition of 1778 keV to the ground state band. The tri-axial shape co-existence is also observed in this nucleus at higher excitation. The experimental results are compared with the Microscopic Hartree-Fock model calculations.

  5. Understanding the mechanical and acoustical characteristics of sand aggregates compacting under triaxial conditions

    NASA Astrophysics Data System (ADS)

    Hangx, Suzanne; Brantut, Nicolas

    2016-04-01

    Mechanisms such as grain rearrangement, coupled with elastic deformation, grain breakage, grain rearrangement, grain rotation, and intergranular sliding, play a key role in determining porosity and permeability reduction during burial of clastic sediments. Similarly, in poorly consolidated, highly porous sands and sandstones, grain rotation, intergranular sliding, grain failure, and pore collapse often lead to significant reduction in porosity through the development of compaction bands, with the reduced porosity and permeability of such bands producing natural barriers to flow within reservoir rocks. Such time-independent compaction processes operating in highly porous water- and hydrocarbon-bearing clastic reservoirs can exert important controls on production-related reservoir deformation, subsidence, and induced seismicity. We performed triaxial compression experiments on sand aggregates consisting of well-rounded Ottawa sand (d = 300-400 μm; φ = 36.1-36.4%) at room temperature, to systematically investigate the effect of confining pressure (Pceff = 5-100 MPa), strain rate (10‑6-10‑4 s‑1) and chemical environment (decane vs. water; Pf = 5 MPa) on compaction. For a limited number of experiments grain size distribution (d = 180-500 μm) and grain shape (subangular Beaujean sand; d = 180-300 μm) were varied to study their effect. Acoustic emission statistics and location, combined with microstructural and grain size analysis, were used to verify the operating microphysical compaction mechanisms. All tests showed significant pre-compaction during the initial hydrostatic (set-up) phase, with quasi-elastic loading behaviour accompanied by permanent deformation during the differential loading stage. This permanent volumetric strain involved elastic grain contact distortion, particle rearrangement, and grain failure. From the acoustic data and grain size analysis, it was evident that at low confining pressure grain rearrangement controlled compaction, with

  6. Strain Measurement of Geological Samples Subjected to Triaxial Stresses Experienced During Hydraulic Loading

    SciTech Connect

    An, Ke; Anovitz, Lawrence {Larry} M; Dessieux Jr, Luc Lucius

    2014-01-01

    locations, subjected to a triaxial stress state. The basis of the method and initial results for simple load conditions were reported at last year s Stanford Geothermal Workshop. This work will report results from recent neutron diffraction strain measurement experiments in which marble samples were subjected to load conditions more representative of hydraulic fracturing operations within a pressure cell specially designed for the reported strain measurement technique.

  7. Energy Dissipation and Release During Coal Failure Under Conventional Triaxial Compression

    NASA Astrophysics Data System (ADS)

    Peng, Ruidong; Ju, Yang; Wang, J. G.; Xie, Heping; Gao, Feng; Mao, Lingtao

    2015-03-01

    Theoretical and experimental studies have revealed that energy dissipation and release play an important role in the deformation and failure of coal rocks. To determine the relationship between energy transformation and coal failure, the mechanical behaviors of coal specimens taken from a 600-m deep mine were investigated by conventional triaxial compression tests using five different confining pressures. Each coal specimen was scanned by microfocus computed tomography before and after testing to examine the crack patterns. Sieve analysis was used to measure the post-failure coal fragments, and a fractal model was developed for describing the size distribution of the fragments. Based on the test results, a damage evolution model of the rigidity degeneration of coal before the peak strength was also developed and used to determine the initial damage and critical damage variables. It was found that the peak strength increased with increasing confining pressure, but the critical damage variable was almost invariant. More new cracks were initiated in the coal specimens when there was no confining pressure or the pressure was too high. The parameters of failure energy ratio β and stress drop coefficient α are further proposed to describe the failure mode of coal under different confining pressures. The test results revealed that β was approximately linearly related to the fractal dimension of the coal fragments and that a higher failure energy ratio corresponded to a larger fractal dimension and more severe failure. The stress drop coefficient α decreased approximately exponentially with increasing confining pressure, and could be used to appropriately describe the evolution of the coal failure mode from brittle to ductile with increasing confining pressure. A large β and small α under a high confining pressure were noticed during the tests, which implied that the failure of the coal was a kind of pseudo-ductile failure. Brittle failure occurred when the confining

  8. Permeability Changes of Coal Cores and Briquettes under Tri-Axial Stress Conditions

    NASA Astrophysics Data System (ADS)

    Wierzbicki, Mirosław; Konečný, Pavel; Kožušníková, Alena

    2014-12-01

    The paper is dealing with the permeability of coal in triaxial state of stress. The permeability of coal, besides coal's methane capacity, is the main parameter determining the quantity of methane inflow into underground excavations. The stress in a coal seam is one of the most important factors influencing coal permeability therefore the permeability measurements were performed in tri-axial state of stress. The hydrostatic three-axial state of stress was gradually increased from 5 MPa with steps of 5 MPa up to a maximum of 30 MPa. Nitrogen was applied as a gas medium in all experiments. The results of the permeability measurements of coal cores from the "Zofiówka" mine, Poland, and three mines from the Czech Republic are presented in this paper. As a "reference", permeability measurements were also taken for coal briquettes prepared from coal dust with defined porosity. It was confirmed that the decreasing porosity of coal briquettes affects the decreasing permeability. The advantage of experimentation on coal briquettes is its good repeatability. From the experimental results, an empirical relation between gas permeability and confining pressure has also been identified. The empirical relation for coal briquettes is in good correspondence with published results. However, for coal cores, the character of change differs. The influence of confining pressure has a different character and the decrease in permeability is stronger due to the increasing confining pressure Przepuszczalność węgla, oprócz pojemności sorpcyjnej względem metanu jest głównym parametrem określającym dopływ metanu do podziemnych wyrobiskach górniczych. W warunkach naturalnych wartość przepuszczalności jest ściśle związana ze stanem naprężenia w pokładzie węgla. W pracy przedstawiono wyniki pomiarów przepuszczalności wykonanych w trójosiowym stanie naprężenia. Hydrostatyczny trójosiowy stan naprężenia stopniowo zwiększano od 5 MPa do maksymalnie 30 MPa z krokiem

  9. Stability of triangular equilibrium points in the elliptic restricted problem of three bodies with radiating and triaxial primaries

    NASA Astrophysics Data System (ADS)

    Narayan, A.; Usha, T.

    2014-05-01

    This paper studies the stability of infinitesimal motions about the triangular equilibrium points in the elliptic restricted three body problem assuming bigger primary as a source of radiation and the smaller one a triaxial rigid body. The perturbation technique developed by Bennet (Icarus 4:177, 1965b) has been used for determination of characteristic exponents. This technique is based on Floquet's Theory for determination of characteristic exponents in the system with periodic coefficients. The results of the study are analytical and numerical expressions are simulated for the transition curves bounding the region of stability in the μ-e plane, accurate to O( e 2). The unstable region is found to be divided into three parts. The effect of radiation parameter is significant. For small values of e, the results are in favor with the numerical analysis of Danby (Astron. J. 69:166, 1964), Bennet (Icarus 4:177, 1965b), Alfriend and Rand (AIAA J. 6:1024, 1969). The effect of radiation pressure is significant than the oblateness and triaxiality of the primaries.

  10. Some like it triaxial: the universality of dark matter halo shapes and their evolution along the cosmic time

    NASA Astrophysics Data System (ADS)

    Despali, Giulia; Giocoli, Carlo; Tormen, Giuseppe

    2014-10-01

    We present a detailed analysis of dark matter halo shapes, studying how the distributions of ellipticity, prolateness and axial ratios evolve as a function of time and mass. With this purpose in mind, we analysed the results of three cosmological simulations, running an ellipsoidal halo finder to measure triaxial halo shapes. The simulations have different scales, mass limits and cosmological parameters, which allows us to ensure a good resolution and statistics in a wide mass range, and to investigate the dependence of halo properties on the cosmological model. We confirm the tendency of haloes to be prolate at all times, even if they become more triaxial going to higher redshifts. Regarding the dependence on mass, more massive haloes are also less spherical at all redshifts, since they are the most recent forming systems and so still retain memory of their original shape at the moment of collapse. We then propose a rescaling of the shape-mass relations, using the variable ν = δc/σ to represent the mass, which absorbs the dependence on both cosmology and time, allowing us to find universal relations between halo masses and shape parameters (ellipticity, prolateness and the axial ratios) which hold at any redshift. This may be very useful to determine prior distributions of halo shapes for observational studies.

  11. Modification of a Macromechanical Finite-Element Based Model for Impact Analysis of Triaxially-Braided Composites

    NASA Technical Reports Server (NTRS)

    Goldberg, Robert K.; Blinzler, Brina J.; Binienda, Wieslaw K.

    2010-01-01

    A macro level finite element-based model has been developed to simulate the mechanical and impact response of triaxially-braided polymer matrix composites. In the analytical model, the triaxial braid architecture is simulated by using four parallel shell elements, each of which is modeled as a laminated composite. For the current analytical approach, each shell element is considered to be a smeared homogeneous material. The commercial transient dynamic finite element code LS-DYNA is used to conduct the simulations, and a continuum damage mechanics model internal to LS-DYNA is used as the material constitutive model. The constitutive model requires stiffness and strength properties of an equivalent unidirectional composite. Simplified micromechanics methods are used to determine the equivalent stiffness properties, and results from coupon level tests on the braided composite are utilized to back out the required strength properties. Simulations of quasi-static coupon tests of several representative braided composites are conducted to demonstrate the correlation of the model. Impact simulations of a represented braided composites are conducted to demonstrate the capability of the model to predict the penetration velocity and damage patterns obtained experimentally.

  12. Effect of open hole on tensile failure properties of 2D triaxial braided textile composites and tape equivalents

    NASA Technical Reports Server (NTRS)

    Norman, Timothy L.; Anglin, Colin; Gaskin, David; Patrick, Mike

    1995-01-01

    The unnotched and notched (open hole) tensile strength and failure mechanisms of two-dimensional (2D) triaxial braided composites were examined. The effect of notch size and notch position were investigated. Damage initiation and propagation in notched and unnotched coupons were also examined. Theory developed to predict the normal stress distribution near an open hole and failure for tape laminated composites was evaluated for its applicability to triaxial braided textile composite materials. Four fiber architectures were considered with different combinations of braid angle, longitudinal and braider yam size, and percentage of longitudinal yarns. Tape laminates equivalent to textile composites were also constructed for comparison. Unnotched tape equivalents were stronger than braided textiles but exhibited greater notch sensitivity. Notched textiles and tape equivalents have roughly the same strength at large notch sizes. Two common damage mechanisms were found: braider yams cracking and near notch longitudinal yarn splitting. Cracking was found to initiate in braider yarns in unnotched and notched coupons, and propagate in the direction of the braider yarns until failure. Longitudinal yarn splitting occurred in three of four architectures that were longitudinally fiber dominated. Damage initiation stress decreased with increasing braid angle. No significant differences in prediction of near notch stress between measured and predicted stress were weak for textiles with large braid angle. Notch strength could not be predicted using existing anisotropic theory for braided textiles due to their insensitivity to notch.

  13. An exact solution for orbit view-periods from a station on a tri-axial ellipsoidal planet

    NASA Technical Reports Server (NTRS)

    Tang, C. C. H.

    1986-01-01

    This paper presents the concise exact solution for predicting view-periods to be observed from a masked or unmasked tracking station on a tri-axial ellipsoidal surface. The new exact approach expresses the azimuth and elevation angles of a spacecraft in terms of the station-centered geodetic topocentric coordinates in an elegantly concise manner. A simple and efficient algorithm is developed to avoid costly repetitive computations in searching for neighborhoods near the rise and set times of each satellite orbit for each station. Only one search for each orbit is necessary for each station. Sample results indicate that the use of an assumed spherical earth instead of an 'actual' tri-axial ellipsoidal earth could introduce an error up to a few minutes in a view-period prediction for circular orbits of low or medium altitude. For an elliptical orbit of high eccentricity and long period, the maximum error could be even larger. The analytic treatment and the efficient algorithm are designed for geocentric orbits, but they should be applicable to interplanetary trajectories by an appropriate coordinates transformation at each view-period calculation. This analysis can be accomplished only by not using the classical orbital elements.

  14. Large Scale Tests on Jointed and Bedded Rocks Under Multi-Stage Triaxial Compression and Direct Shear

    NASA Astrophysics Data System (ADS)

    Vergara, Maximiliano R.; Kudella, Peter; Triantafyllidis, Theodoros

    2015-01-01

    The mechanical behavior of bedded and jointed rock was examined in the context of the design of slopes, tunnels and tunnel portals along a planned new rail line. To obtain representative properties for describing the mechanical behavior of this material, large scale triaxial tests were performed. Specimens with a size of 60 cm diameter and 120 cm height composed of sandstone and claystone beds were tested in triaxial compression using a multi-stage technique. The specimens showed a ductile behavior for the stress regime tested. The strength parameters were calculated according to the Mohr-Coulomb failure criterion. The axial and volumetric deformations were measured and the viscosity of the composite rock material was assessed by deformation rate alterations. For some specimens, direct shear tests were conducted in samples containing joints. The results of the tests show that the failure of the bedded specimens was given by the combined failure of both materials. This was confirmed by a numerical model including rock discontinuities.

  15. 75 FR 31464 - Certification of the Attorney General; Shannon County, SD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-03

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF JUSTICE Certification of the Attorney General; Shannon County, SD In accordance with Section 8 of the Voting Rights Act, 42 U.S.C. 1973f, I hereby certify that in my judgment the appointment of federal observers is necessary to enforce the guarantees of...

  16. AmeriFlux US-SdH Nebraska SandHills Dry Valley

    SciTech Connect

    Arkebauer, Tim J.; Billesbach, Dave

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site US-SdH Nebraska SandHills Dry Valley. Site Description - The Nebraska SandHills Dry Valley tower is located on public land owned by the University of Nebraska-Lincoln. The site is on a research cattle ranch where grazing primarily takes place.

  17. Semi-automatic geographic atrophy segmentation for SD-OCT images

    PubMed Central

    Chen, Qiang; de Sisternes, Luis; Leng, Theodore; Zheng, Luoluo; Kutzscher, Lauren; Rubin, Daniel L.

    2013-01-01

    Geographic atrophy (GA) is a condition that is associated with retinal thinning and loss of the retinal pigment epithelium (RPE) layer. It appears in advanced stages of non-exudative age-related macular degeneration (AMD) and can lead to vision loss. We present a semi-automated GA segmentation algorithm for spectral-domain optical coherence tomography (SD-OCT) images. The method first identifies and segments a surface between the RPE and the choroid to generate retinal projection images in which the projection region is restricted to a sub-volume of the retina where the presence of GA can be identified. Subsequently, a geometric active contour model is employed to automatically detect and segment the extent of GA in the projection images. Two image data sets, consisting on 55 SD-OCT scans from twelve eyes in eight patients with GA and 56 SD-OCT scans from 56 eyes in 56 patients with GA, respectively, were utilized to qualitatively and quantitatively evaluate the proposed GA segmentation method. Experimental results suggest that the proposed algorithm can achieve high segmentation accuracy. The mean GA overlap ratios between our proposed method and outlines drawn in the SD-OCT scans, our method and outlines drawn in the fundus auto-fluorescence (FAF) images, and the commercial software (Carl Zeiss Meditec proprietary software, Cirrus version 6.0) and outlines drawn in FAF images were 72.60%, 65.88% and 59.83%, respectively. PMID:24409376

  18. 76 FR 48120 - Black Hills National Forest, Custer, SD-Mountain Pine Beetle Response Project

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-08

    ... Forest Service Black Hills National Forest, Custer, SD--Mountain Pine Beetle Response Project AGENCY...: This project proposes to treat areas newly infested by mountain pine beetles on approximately 325,000...-rocky-mountain-black-hills@fs.fed.us , with ``MPB Response Project'' in the subject line....

  19. Quasicontinuous spectrum of γ rays which feed and depopulate SD in ^194Pb.

    NASA Astrophysics Data System (ADS)

    McNabb, D. P.; Cizewski, J. A.; Ding, K.-Y.; Younes, W.; Khoo, T. L.; Lauritsen, T.; Archer, D. E.; Bauer, R. W.; Becker, J. A.; Bernstein, L. A.; Hauschild, K.; Clark, R. M.; Deleplanque, M. A.; Diamond, R. M.; Fallon, P.; Lee, I. Y.; Macchiavelli, A. O.; Stephens, F. S.; Kelly, W. H.

    1996-10-01

    The mechanism for decay from superdeformed (SD) to ``normal'' (ND) states in ^192Hg results in a large quasicontinuum component which can be fit by a statistical model.(R.G. Henry, et al., Phys. Rev. Lett. 73), 777 (1994). Recent experiments(M.J. Brinkman, et al., Phys. Rev. C53), R1461 (1996); T.L. Khoo, et al., Phys. Rev. Lett. 76, 1583 (1996). have also identified discrete one-step decays from SD to ND states in ^194Pb and ^194Hg which have allowed for the determination of excitation energy and spin of the second wells in these nuclei. We used the ^174Yb(^25Mg,5n) reaction at 130 MeV with a backed target and Gammasphere to study the total spectrum of γ rays in coincidence with the yrast SD band in ^194Pb. The response functions of the detectors were previously determined. The results of the preliminary analysis on the quasicontinuous γ rays which feed and depopulate the yrast SD band will be presented. This work was supported in part by the National Science Foundation and the U.S. Department of Energy.

  20. 78 FR 31430 - Proposed Establishment of Class E Airspace; Wagner, SD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-24

    ...This action proposes to establish Class E airspace at Wagner, SD. Controlled airspace is necessary to accommodate new Standard Instrument Approach Procedures (SIAP) at Wagner Municipal Airport. The FAA is taking this action to enhance the safety and management of Instrument Flight Rules (IFR) operations for SIAPs at the...

  1. 78 FR 25232 - Proposed Establishment of Class E Airspace; Parkston, SD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-30

    ...This action proposes to establish Class E airspace at Parkston, SD. Controlled airspace is necessary to accommodate new Standard Instrument Approach Procedures (SIAP) at Parkston Municipal Airport. The FAA is taking this action to enhance the safety and management of Instrument Flight Rules (IFR) operations for SIAPs at the...

  2. 78 FR 49985 - Proposed Establishment of Class E Airspace; Sisseton, SD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-16

    ...This action proposes to establish Class E airspace at Sisseton, SD. Controlled airspace is necessary to accommodate new Standard Instrument Approach Procedures (SIAP) at Sisseton Municipal Airport. The FAA is taking this action to enhance the safety and management of Instrument Flight Rules (IFR) operations for SIAPs at the...

  3. SD-GIS-based temporal-spatial simulation of water quality in sudden water pollution accidents

    NASA Astrophysics Data System (ADS)

    Zhang, Bo; Qin, Yu; Huang, Mingxiang; Sun, Qiang; Li, Shun; Wang, Liqiang; Yu, Chaohui

    2011-07-01

    System dynamics (SD) is well suited for studying dynamic nonlinear complex systems. In this paper, SD is applied to a rapid-onset water pollution accident using a 1-D water quality model and a conceptual GIS-SD framework is constructed to simulate the temporal-spatial changes of pollutant concentration. Based on the component GIS and the SD model, a prototype system of water quality simulation in water pollution accidents is developed. The data collected on the spot in the Songhua River water pollution accident in November 2005 were used for model parameter calibration and model validation. The results showed that: (1) the constructed model could simulate the changes of nitrobenzene concentration with time in the Songhua River water pollution accident, especially during the peak concentration and at the arrival time of peak concentration, and that the simulated values and the on-the-spot monitored values corresponded with each other well; (2) the scenario simulation could be made by adjusting parameters u (longitudinal current velocity), E (longitudinal diffusion coefficient), and k (decay rate coefficient). Such a model can provide decision makers with quantitative information to optimize related emergency response measures.

  4. High Production of Squalene Using a Newly Isolated Yeast-like Strain Pseudozyma sp. SD301.

    PubMed

    Song, Xiaojin; Wang, Xiaolong; Tan, Yanzhen; Feng, Yingang; Li, Wenli; Cui, Qiu

    2015-09-30

    A yeast-like fungus, termed strain SD301, with the ability to produce a high concentration of squalene, was isolated from Shuidong Bay, China. The nucleotide sequence analysis of the internal transcribed spacer (ITS) region of SD301 indicated the strain belonged to Pseudozyma species. The highest biomass and squalene production of SD301 were obtained when glucose and yeast extracts were used as the carbon and nitrogen sources, respectively, with a C/N ratio of 3. The optimal pH and temperature were 6 and 25 °C, with 15 g L(-1) of supplemented sea salt. The maximum squalene productivity reached 0.039 g L(-1) h(-1) in batch fermentation, while the maximum squalene yield of 2.445 g L(-1) was obtained in fed-batch fermentation. According to our knowledge, this is the highest squalene yield produced thus far using fermentation technology, and the newly isolated strain Pseudozyma sp. SD301 is a promising candidate for commercial squalene production. PMID:26350291

  5. Linear in-wavenumber optical spectrum registration in SD-OCT

    NASA Astrophysics Data System (ADS)

    Gelikonov, Grigory V.; Gelikonov, Valentin M.; Shilyagin, Pavel A.

    2012-01-01

    An efficient technique of linear in-wavenumber optical spectrum registration in SD-OCT is proposed. Methods of partial phase correction of registered optical spectrum for in-wavenumber linearization are described and investigated. The decrease sensitivity decay with depth increasing degeneration is presented. The experimental results for sample media are presented.

  6. 78 FR 24228 - Lake Andes National Wildlife Refuge Complex, Lake Andes, SD; Final Comprehensive Conservation Plan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-24

    ... review and comment following the announcement in the Federal Register on October 29, 2012 ] (77 FR 65574... Fish and Wildlife Service Lake Andes National Wildlife Refuge Complex, Lake Andes, SD; Final... conservation plan and finding of no significant impact (FONSI) for the Lake Andes National Wildlife...

  7. Properties of triaxial, strongly deformed bands in {sup 167}Ta and {sup 167}Lu and the top-on-top model

    SciTech Connect

    Sugawara-Tanabe, Kazuko; Tanabe, Kosai

    2010-11-15

    Based on the particle-rotor model with one particle coupled to a triaxially deformed rotor, the experimental excitation energy relative to a reference E*-aI(I+1) and the ratio between interband and intraband electromagnetic transitions are well reproduced for {sup 167}Ta with {gamma}=19 deg. The same parameter set for the angular-momentum-dependent rigid-body moments of inertia attains good agreement with experimental data for the positive-parity triaxial, strongly deformed (TSD) band levels in {sup 167}Lu. An attempt is made to investigate the negative-parity TSD band in {sup 167}Lu.

  8. Exploring Stellar Evolution Models of sdB Stars using MESA

    NASA Astrophysics Data System (ADS)

    Schindler, Jan-Torge; Green, Elizabeth M.; Arnett, W. David

    2015-06-01

    Stellar evolution calculations have had great success reproducing the observed atmospheric properties of different classes of stars. Recent detections of g-mode pulsations in evolved He burning stars allow a rare comparison of their internal structure with stellar models. Asteroseismology of subdwarf B (sdB) stars suggests convective cores of 0.22-0.28 M⊙, ≳45% of the total stellar mass. Previous studies found significantly smaller convective core masses (≲0.19 M⊙) at a comparable evolutionary stage. We evolved stellar models with Modules for Experiments in Stellar Astrophysics (MESA) to explore how well the interior structures inferred from asteroseismology can be reproduced by standard algorithms. Our qualitative evolutionary paths, position in the log g-{{T}eff} diagram, and model timescales are consistent with previous results. The sdB masses from our full evolutionary sequences fall within the range of the empirical sdB mass distribution, but are nearly always lower than the median. Using standard MLT with atomic diffusion we find convective core masses of ˜0.17-0.18 M⊙, averaged over the entire sdB lifetime. We can increase the convective core sizes to be as large as those inferred from asteroseismology, but only for extreme values of the overshoot parameter (overshoot gives numerically unstable and physically unrealistic behavior at the boundary). High resolution three-dimensional simulations of turbulent convection in stars suggest that the Schwarzschild criterion for convective mixing systematically underestimates the actual extent of mixing because a boundary layer forms. Accounting for this would decrease the errors in both sdB total and convective core masses.

  9. Using Tri-Axial Accelerometers to Assess the Dynamic Control of Head Posture During Gait

    NASA Technical Reports Server (NTRS)

    Lawrence, John H., III

    2003-01-01

    Long duration spaceflight is known to cause a variety of biomedical stressors to the astronaut. One of the more functionally destabilizing effects of spaceflight involves microgravity-induced changes in vestibular or balance control. Balance control requires the integration of the vestibular, visual, and proprioceptive systems. In the microgravity environment, the normal gravity vector present on Earth no longer serves as a reference for the balance control system. Therefore, adaptive changes occur to the vestibular system to affect control of body orientation with altered, or non-present, gravity and/or proprioceptive inputs. Upon return to a gravity environment, the vestibular system must re-incorporate the gravity vector and gravity-induced proprioceptive inputs into the balance control regime. The result is often a period of postural instability, which may also be associated with space motion sickness (oscillopsia, nausea, and vertigo). Previous studies by the JSC Neuroscience group have found that returning astronauts often employ alterations in gait mechanics to maintain postural control during gait. It is believed that these gait alterations are meant to decrease the transfer of heel strike shock energy to the head, thus limiting the contradictory head and eye movements that lead to gait instability and motion sickness symptoms. We analyzed pre- and post-spaceflight tri-axial accelerometer data from the NASA/MIR long duration spaceflight missions to assess the heel to head transfer of heel strike shock energy during locomotion. Up to seven gait sessions (three preflight, four postflight) of head and shank (lower leg) accelerometer data was previously collected from six astronauts who engaged in space flights of four to six months duration. In our analysis, the heel to head transmission of shock energy was compared using peak vertical acceleration (a), peak jerk (j) ratio, and relative kinetic energy (a). A host of generalized movement variables was produced

  10. Elastic wave velocity and acoustic emission monitoring during Gypsum dehydration under triaxial stress conditions

    NASA Astrophysics Data System (ADS)

    Brantut, N.; David, E. C.; Héripré, E.; Schubnel, A. J.; Zimmerman, R. W.; Gueguen, Y.

    2010-12-01

    Dehydration experiments were performed on natural Gypsum polycrystal samples coming from Volterra, Italy in order to study contemporaneously the evolution of P and S elastic wave velocities and acoustic emission (AE) triggering. During these experiments, temperature was slowly raised at 0.15 degrees C per minute under constant stress conditions. Two experiments were realized under quasi-hydrostatic stress (15 and 55 MPa respectively). The third experiment was realized under constant triaxial stress (σ3=45MPa, σ1=75MPa). All three were drained (10MPa constant pore pressure). In each experiments, both P and S wave velocities reduced drastically (as much as approx. 50% in the low confining pressure case) at the onset of dehydration. Importantly, the Vp/Vs ratio also decreased. Shortly after the onset of decrease in P and S wave velocities, the dehydration reaction was also accompanied by bursts of AEs. Time serie locations of the AEs show that they initiated from the pore pressure port, ie from where the pore fluid could easily be drained, and then slowly migrated within the sample. In each experiments, the AE rate could be positively correlated to the reaction rate, inferred from pore volumetry. In such a way, the AE rate reached a peak when the reaction was the fastest. Focal mechanism analysis of the largest AEs showed they had a large volumetric component in compaction, confirming that AEs were indeed related to pore closure and/or collapse. In addition, the AE rate also increased with confinement, ie when a larger amount of compaction was observed. Interestingly, when under differential stress conditions, AE focal mechanisms were mainly in shear. Additional dehydration experiments performed within an environmental scanning electron microscope under low vacuum highlight that, in drained conditions at least, the reaction seems to take place in two phases. First, cracks are being opened along cleavage planes within a single gypsum crystal, which allows for the

  11. Automated Segmentability Index for Layer Segmentation of Macular SD-OCT Images

    PubMed Central

    Lee, Kyungmoo; Buitendijk, Gabriëlle H.S.; Bogunovic, Hrvoje; Springelkamp, Henriët; Hofman, Albert; Wahle, Andreas; Sonka, Milan; Vingerling, Johannes R.; Klaver, Caroline C.W.; Abràmoff, Michael D.

    2016-01-01

    Purpose To automatically identify which spectral-domain optical coherence tomography (SD-OCT) scans will provide reliable automated layer segmentations for more accurate layer thickness analyses in population studies. Methods Six hundred ninety macular SD-OCT image volumes (6.0 × 6.0 × 2.3 mm3) were obtained from one eyes of 690 subjects (74.6 ± 9.7 [mean ± SD] years, 37.8% of males) randomly selected from the population-based Rotterdam Study. The dataset consisted of 420 OCT volumes with successful automated retinal nerve fiber layer (RNFL) segmentations obtained from our previously reported graph-based segmentation method and 270 volumes with failed segmentations. To evaluate the reliability of the layer segmentations, we have developed a new metric, segmentability index SI, which is obtained from a random forest regressor based on 12 features using OCT voxel intensities, edge-based costs, and on-surface costs. The SI was compared with well-known quality indices, quality index (QI), and maximum tissue contrast index (mTCI), using receiver operating characteristic (ROC) analysis. Results The 95% confidence interval (CI) and the area under the curve (AUC) for the QI are 0.621 to 0.805 with AUC 0.713, for the mTCI 0.673 to 0.838 with AUC 0.756, and for the SI 0.784 to 0.920 with AUC 0.852. The SI AUC is significantly larger than either the QI or mTCI AUC (P < 0.01). Conclusions The segmentability index SI is well suited to identify SD-OCT scans for which successful automated intraretinal layer segmentations can be expected. Translational Relevance Interpreting the quantification of SD-OCT images requires the underlying segmentation to be reliable, but standard SD-OCT quality metrics do not predict which segmentations are reliable and which are not. The segmentability index SI presented in this study does allow reliable segmentations to be identified, which is important for more accurate layer thickness analyses in research and population studies. PMID:27066311

  12. KIC 7668647: a 14 day beaming sdB+WD binary with a pulsating subdwarf

    NASA Astrophysics Data System (ADS)

    Telting, J. H.; Baran, A. S.; Nemeth, P.; Østensen, R. H.; Kupfer, T.; Macfarlane, S.; Heber, U.; Aerts, C.; Geier, S.

    2014-10-01

    The recently discovered subdwarf B (sdB) pulsator KIC 7668647 is one of the 18 pulsating sdB stars detected in the Kepler field. It features a rich g-mode frequency spectrum, with a few low-amplitude p-modes at short periods. This makes it a promising target for a seismic study aiming to constrain the internal structure of this star, and of sdB stars in general. We use new ground-based low-resolution spectroscopy, and the near-continuous 2.88 year Kepler light curve, to reveal that KIC 7668647 consists of a subdwarf B star with an unseen white-dwarf companion with an orbital period of 14.2 d. An orbit with a radial-velocity amplitude of 39 km s-1 is consistently determined from the spectra, from the orbital Doppler beaming seen by Kepler at 163 ppm, and from measuring the orbital light-travel delay of 27 s by timing of the many pulsations seen in the Kepler light curve. The white dwarf has a minimum mass of 0.40 M⊙. We use our high signal-to-noise average spectra to study the atmospheric parameters of the sdB star, and find that nitrogen and iron have abundances close to solar values, while helium, carbon, oxygen and silicon are underabundant relative to the solar mixture. We use the full Kepler Q06-Q17 light curve to extract 132 significant pulsation frequencies. Period-spacing relations and multiplet splittings allow us to identify the modal degree ℓ for the majority of the modes. Using theg-mode multiplet splittings we constrain the internal rotation period at the base of the envelope to 46-48 d as a first seismic result for this star. The few p-mode splittings may point at a slightly longer rotation period further out in the envelope of the star. From mode-visibility considerations we derive that the inclination of the rotation axis of the sdB in KIC 7668647 must be around ~60°. Furthermore, we find strong evidence for a few multiplets indicative of degree 3 ≤ ℓ ≤ 8, which is another novelty in sdB-star observations made possible by Kepler. Based on

  13. Test characteristics of two rapid antigen detection tests (SD FK50 and SD FK60) for the diagnosis of malaria in returned travellers

    PubMed Central

    Van der Palen, Mirna; Gillet, Philippe; Bottieau, Emmanuel; Cnops, Lieselotte; Van Esbroeck, Marjan; Jacobs, Jan

    2009-01-01

    Background Two malaria rapid diagnostic tests were evaluated in a travel clinic setting: the SD FK50 Malaria Ag Plasmodium falciparum test (a two-band test) and the SD FK60 Malaria Ag P. falciparum/Pan test (a three-band test). Methods A panel of stored whole blood samples (n = 452 and n = 614 for FK50 and FK60, respectively) from returned travellers was used. The reference method was microscopy with PCR in case of discordant results. Results For both tests, overall sensitivity for the detection of P. falciparum was 93.5%, reaching 97.6% and 100% at parasite densities above 100 and 1,000/μl respectively. Overall sensitivities for Plasmodium vivax, Plasmodium ovale and Plasmodium malariae for the FK60 test were 87.5%, 76.3% and 45.2%, but they reached 92.6% and 90.5% for P. vivax and P. ovale at parasite densities above 500/μl. Specificities were above 95% for all species and both tests when corrected by PCR, with visible histidine-rich protein-2 lines for P. malariae (n = 3) and P. vivax and P. ovale (1 sample each). Line intensities were reproducible and correlated to parasite densities. The FK60 tests provided clues to estimate parasite densities for P. falciparum below or above 1,000/μl. Conclusion Both the FK50 and FK60 performed well for the diagnosis of P. falciparum in the present setting, and the FK60 for the diagnosis of P. vivax and P. ovale at parasite densities > 500/μl. The potential use of the FK60 as a semi-quantitative estimation of parasite density needs to be further explored. PMID:19416497

  14. Reducing the artifacts in the identification of outer retinal boundary in the SD-OCT image with inherit retinal dystrophies.

    PubMed

    Min Zhang; Sekiguchi, Hiroyuki; Uji, Akihito; Yakami, Masahiro; Togashi, Kaori

    2015-08-01

    This paper presents a new SD-OCT outer retinal boundary identification method based on the improved graph-theoretic approach in SD-OCT retinal image, which is robust to the image quality degradation and the pathological morphology variability. The performance of the proposed method was verified using the SD-OCT image database with inherit retinal dystrophies, which suffer from the artifacts most among different macular degeneration diseases. The experimental results of the subjective evaluation indicated that the identification results using the proposed method was substantially improved compared with the current built-in software in the SD-OCT devices. PMID:26737258

  15. Creation of short microwave ablation zones: In Vivo Characterization of single and paired Modified Triaxial Antennas Laboratory Investigation

    PubMed Central

    Lubner, Meghan G.; Ziemlewicz, Tim J; Hinshaw, J. Louis; Lee, Fred T.; Sampson, Lisa J.; Brace, Chris L.

    2014-01-01

    Purpose To characterize modified triaxial microwave antennas configured to produce short ablation zones. Materials and Methods 50 single- and 27 paired-antenna hepatic ablations were performed in domestic swine (n=11) with 17-gauge, gas-cooled modified triaxial antennas powered at 65W from a 2.45 GHz generator. Single-antenna ablations were performed at 2 (n=16), 5 (n=21), and 10 (n=13) minutes. Paired-antenna ablations were performed at 1-cm and 2-cm spacing for 5 (n=7, n=8) and 10 minutes (n=7, n=5). Mean transverse width, length and aspect ratio of sectioned ablation zones were measured and compared. Results For single antennas, mean ablation zone length was 2.9±0.45, 3.5±0.55 and 4.2±0.40 cm at 2, 5, and 10 minutes respectively. Mean width was 1.8±0.3, 2.0±0.32, 2.5±0.25 cm at 2, 5, and 10 minutes. For paired antennas, mean length at 5 min 1 and 2 cm and 10 min 1 and 2 cm spacing was 4.2±0.9, 4.4±0.9, 4.8±0.5 and 4.3±0.9 cm respectively. Mean width was 3.1±1.0, 4.0±0.8 and 3.8±0.4, 4.2±0.6 cm respectively. Paired-antenna ablations were more spherical (aspect ratios 0.72-0.79 for 5-10 min) than single-antenna ablations (0.57-0.59). For paired-antenna ablations, 1 cm spacing appeared optimal, with improved circularity and decreased clefting compared to 2 cm spacing (circ 1 cm 0.85, 2 cm 0.78). Conclusion Modified triaxial antennas can generate relatively short, spherical ablation zones. Paired-antenna ablations were rounder and larger in transverse dimension compared to single antenna ablations, with 1 cm spacing optimal for confluence of the ablation zone. PMID:25156644

  16. Chiral magnetic effect and SdH oscillations in Dirac and Weyl metals

    NASA Astrophysics Data System (ADS)

    Kharzeev, Dmitri; Monteiro, Gustavo; Abanov, Alexander

    2015-03-01

    In the present work, we consider the interplay of chiral anomaly and Shubnikov-de Haas (SdH) oscillations in recently discovered Dirac metals. The kinetic theory describing the transport in these new materials should account for the chiral anomaly. The unbalanced number of chiral zero-modes in the presence of magnetic field due to the chiral anomaly gives rise to an additional contribution to the electric current - the chiral magnetic effect. The zero-modes are topologically protected from scattering and their contribution to the current leads to a negative magnetoresistance. This effect was recently observed in measurements on the Dirac semimetal Cd3 As2, where the longitudinal (with respect to magnetic field) component of the resistivity tensor shows a negative slope, along with pronounced Shubnikov-de Haas (SdH) oscillations. We develop a combined description of both these phenomena within a chiral kinetic theory.

  17. HS 2333 + 3927: a new sdB binary with a large reflection effect

    NASA Astrophysics Data System (ADS)

    Karl, C. A.; Heber, U.; Drechsel, H.; Napiwotzki, R.; Altmann, M.; Østensen, R.; Folkes, S.; Solheim, J. E.; Cordes, O.; Voss, B.; Koester, D.

    2004-06-01

    We report the discovery of a binary, HS 2233 + 3927, consisting of an sdB star with a faint companion. From its lightcurve the orbital period of 14,844 s, the mass ratio, the inclination, and other system parameters are derived. The companion does not contribute to the optical light of the system except through a strong reflection effect. The semi-amplitude of the radial velocity curve K 1= 89.6 km/s-1 and a mass function of f(m) = 0.013 M ⊙ are determined. A preliminary spectroscopic analysis of the blue spectra using NLTE model atmospheres results in Teff= 36 500 K, log g= 5.70, and log(n He/n H) =-2.15. These parameters are typical for sdB stars, the companion is probably an M dwarf.

  18. Fragmentation-aware service provisioning for advance reservation multicast in SD-EONs.

    PubMed

    Li, Shengru; Lu, Wei; Liu, Xiahe; Zhu, Zuqing

    2015-10-01

    In this paper, we study the service provisioning schemes for dynamic advance reservation (AR) multicast requests in elastic optical networks (EONs). We first propose several algorithms that can handle the service scheduling and routing and spectrum assignment (RSA) of AR multicast requests jointly, including an integrated two-dimensional fragmentation-aware RSA (2D-FMA) that can alleviate the 2D fragmentation caused by light-tree provisioning. Then, we leverage the idea of software-defined EONs (SD-EONs) that utilizes OpenFlow (OF) in the control plane to demonstrate and evaluate the proposed algorithms. Specifically, we build an SD-EON control plane testbed, implement the algorithms in it, and perform control plane experiments on dynamic AR multicast provisioning. The results indicate that 2D-FMA achieves the best blocking performance and provides the shortest average setup delay. PMID:26480094

  19. Tri-axial magnetic anisotropies in RE{sub 2}Ba{sub 4}Cu{sub 7}O{sub 15−y} superconductors

    SciTech Connect

    Horii, Shigeru Doi, Toshiya; Okuhira, Shota; Yamaki, Momoko; Kishio, Kohji; Shimoyama, Jun-ichi

    2014-03-21

    We report a novel quantification method of tri-axial magnetic anisotropy in orthorhombic substances containing rare earth (RE) ions using tri-axial magnetic alignment and tri-axial magnetic anisotropies depending on the type of RE in RE-based cuprate superconductors. From the changes in the axes for magnetization in magnetically aligned powders of (RE′{sub 1−x}RE″{sub x}){sub 2}Ba{sub 4}Cu{sub 7}O{sub y} [(RE′,RE″)247] containing RE ions with different single-ion magnetic anisotropies, the ratios of three-dimensional magnetic anisotropies between RE′247 and RE″247 could be determined. The results in (Y,Er)247, (Dy,Er)247, (Ho,Er)247, and (Y,Eu)247 systems suggest that magnetic anisotropies largely depended on the type of RE′ (or RE″), even in the heavy RE ions with higher magnetic anisotropies. An appropriate choice of RE ions in RE-based cuprate superconductors enables the reduction of the required magnetic field for the production of their bulks and thick films based on the tri-axial magnetic alignment technique using modulated rotation magnetic fields.

  20. Correlations of excited states for sd bosons in the presence of random interactions

    SciTech Connect

    Lei, Y.; Zhao, Y. M.; Yoshida, N.; Arima, A.

    2011-04-15

    In this work we study the yrast states of sd-boson systems in the presence of random interactions. It is found that the yrast states with spin-zero ground states among the random ensemble exhibit strong correlations, characterized by anharmonic vibration, s-boson or d-boson condensation, as well as vibrational and rotational motions. We study these correlations explicitly based on their wave functions and the features of two-body interactions in the random ensemble.

  1. Inversion for Eigenvalues and Modes Using Sierra-SD and ROL.

    SciTech Connect

    Walsh, Timothy; Aquino, Wilkins; Ridzal, Denis; Kouri, Drew Philip

    2015-12-01

    In this report we formulate eigenvalue-based methods for model calibration using a PDE-constrained optimization framework. We derive the abstract optimization operators from first principles and implement these methods using Sierra-SD and the Rapid Optimization Library (ROL). To demon- strate this approach, we use experimental measurements and an inverse solution to compute the joint and elastic foam properties of a low-fidelity unit (LFU) model.

  2. Metabolomics approach to serum biomarker for loperamide-induced constipation in SD rats.

    PubMed

    Kim, Ji-Eun; Lee, Young-Ju; Kwak, Moon-Hwa; Jun, Go; Koh, Eun-Kyoung; Song, Sung-Hwa; Seong, Ji-Eun; Kim, Ji Won; Kim, Kyu-Bong; Kim, Suhkmann; Hwang, Dae-Youn

    2014-03-01

    Loperamide has long been known as an opioid-receptor agonist useful as a drug for treatment of diarrhea resulting from gastroenteritis or inflammatory bowel disease as well as to induce constipation. To determine and characterize putative biomarkers that can predict constipation induced by loperamide treatment, alteration of endogenous metabolites was measured in the serum of Sprague Dawley (SD) rats treated with loperamide for 3 days using (1)H nuclear magnetic resonance ((1)H NMR) spectral data. The amounts and weights of stool and urine excretion were significantly lower in the loperamide-treated group than the No-treated group, while the thickness of the villus, crypt layer, and muscle layer was decreased in the transverse colon of the same group. The concentrations of aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and creatinine (Cr) were also slightly changed in the loperamide-treated group, although most of the serum components were maintained at a constant level. Furthermore, pattern recognition of endogenous metabolites showed completely separate clustering of the serum analysis parameters between the No-treated group and loperamide-treated group. Among 35 endogenous metabolites, four amino acids (alanine, glutamate, glutamine and glycine) and six endogenous metabolites (acetate, glucose, glycerol, lactate, succinate and taurine) were dramatically decreased in loperamide-treated SD rats. These results provide the first data pertaining to metabolic changes in SD rats with loperamide-induced constipation. Additionally, these findings correlate the changes in 10 metabolites with constipation. PMID:24707303

  3. Symmetry of Isoscalar Matrix Elements and Systematics in the sd and beginning of fp shells

    NASA Astrophysics Data System (ADS)

    Orce, J. N.; Petkov, P.; Velázquez, V.; McKay, C. J.; Lesher, S. R.; Choudry, S.; Mynk, M.; Linnemann, A.; Jolie, J.; von Brentano, P.; Werner, V.; Yates, S. W.; McEllistrem, M. T.

    2006-03-01

    A careful determination of the lifetime and measurement of the branching ratio for decay of the first 2T=1+ state in 42Sc has allowed an accurate experimental test of charge independence in the A = 42 isobaric triplet. A lifetime of 69(17) fs was measured at the University of Kentucky, while relative intensities for the 975 keV and 1586 keV transitions depopulating the first 2T=1+ state have been determined at the University of Cologne as 100(1) and 8(1), respectively. Both measurements give an isoscalar matrix element, M0, of 6.4(9) (W.u.)1/2. This result confirms charge independence for the A=42 isobaric triplet. Shell model calculations have been carried out for understanding the global trend of M0 values for A = 4n + 2 isobaric triplets ranging from A = 18 to A = 42. The 21 (T=1)+ → 01 (T=1)+ transition energies, reduced transition probabilities and M0 values are reproduced to a high degree of accuracy. The trend of M0 strength along the sd shell is interpreted in terms of the shell structure. Certain discrepancies arise at the extremes of the sd shell, for the A = 18 and A = 38 isobaric triplets, which might be explained in terms of the low valence space at the extremes of the sd shell.

  4. Geology of the USW SD-12 drill hole Yucca Mountain, Nevada

    SciTech Connect

    Rautman, C.A.; Engstrom, D.A.

    1996-11-01

    Drill hole USW SD-12 is one of several holes drilled under Site Characterization Plan Study 8.3.1.4.3.1, also known as the {open_quotes}Systematic Drilling Program,{close_quotes} as part of the U.S. Department of Energy characterization program at Yucca Mountain, Nevada, which has been proposed as the potential location of a repository for high-level nuclear waste. The SD-12 drill hole is located in the central part of the potential repository area, immediately to the west of the Main Test Level drift of the Exploratory Studies Facility and slightly south of midway between the North Ramp and planned South Ramp declines. Drill hole USW SD-12 is 2166.3 ft (660.26 m) deep, and the core recovered essentially complete sections of ash-flow tuffs belonging to the lower half of the Tiva Canyon Tuff, the Pah Canyon Tuff, and the Topopah Spring Tuff, all of which are part of the Miocene Paintbrush Group. A virtually complete section of the Calico Hills Formation was also recovered, as was core from the entire Prow Pass Tuff formation of the Crater Flat Group.

  5. Metabolomics approach to serum biomarker for loperamide-induced constipation in SD rats

    PubMed Central

    Kim, Ji-Eun; Lee, Young-Ju; Kwak, Moon-Hwa; Jun, Go; Koh, Eun-Kyoung; Song, Sung-Hwa; Seong, Ji-Eun; Kim, Ji Won; Kim, Kyu-Bong; Kim, Suhkmann

    2014-01-01

    Loperamide has long been known as an opioid-receptor agonist useful as a drug for treatment of diarrhea resulting from gastroenteritis or inflammatory bowel disease as well as to induce constipation. To determine and characterize putative biomarkers that can predict constipation induced by loperamide treatment, alteration of endogenous metabolites was measured in the serum of Sprague Dawley (SD) rats treated with loperamide for 3 days using 1H nuclear magnetic resonance (1H NMR) spectral data. The amounts and weights of stool and urine excretion were significantly lower in the loperamide-treated group than the No-treated group, while the thickness of the villus, crypt layer, and muscle layer was decreased in the transverse colon of the same group. The concentrations of aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and creatinine (Cr) were also slightly changed in the loperamide-treated group, although most of the serum components were maintained at a constant level. Furthermore, pattern recognition of endogenous metabolites showed completely separate clustering of the serum analysis parameters between the No-treated group and loperamide-treated group. Among 35 endogenous metabolites, four amino acids (alanine, glutamate, glutamine and glycine) and six endogenous metabolites (acetate, glucose, glycerol, lactate, succinate and taurine) were dramatically decreased in loperamide-treated SD rats. These results provide the first data pertaining to metabolic changes in SD rats with loperamide-induced constipation. Additionally, these findings correlate the changes in 10 metabolites with constipation. PMID:24707303

  6. Symmetry of Isoscalar Matrix Elements and Systematics in the sd and beginning of fp shells

    SciTech Connect

    Orce, J. N.; McKay, C. J.; Lesher, S. R.; Choudry, S.; Mynk, M.; McEllistrem, M. T.; Petkov, P.; Velazquez, V.; Linnemann, A.; Jolie, J.; Brentano, P. von; Werner, V.; Yates, S. W.

    2006-03-13

    A careful determination of the lifetime and measurement of the branching ratio for decay of the first 2{sub T=1}{sup +} state in 42Sc has allowed an accurate experimental test of charge independence in the A = 42 isobaric triplet. A lifetime of 69(17) fs was measured at the University of Kentucky, while relative intensities for the 975 keV and 1586 keV transitions depopulating the first 2{sub T=1}{sup +} state have been determined at the University of Cologne as 100(1) and 8(1), respectively. Both measurements give an isoscalar matrix element, M0, of 6.4(9) (W.u.)1/2. This result confirms charge independence for the A=42 isobaric triplet. Shell model calculations have been carried out for understanding the global trend of M0 values for A = 4n + 2 isobaric triplets ranging from A = 18 to A = 42. The 2{sub 1(T=1)}{sup +} {yields} 0{sub 1(T=1)}{sup +} transition energies, reduced transition probabilities and M0 values are reproduced to a high degree of accuracy. The trend of M0 strength along the sd shell is interpreted in terms of the shell structure. Certain discrepancies arise at the extremes of the sd shell, for the A = 18 and A 38 isobaric triplets, which might be explained in terms of the low valence space at the extremes of the sd shell.

  7. Scientific Use of the Sampler, Drill and Distribution Subsystem (SD2)

    NASA Astrophysics Data System (ADS)

    Armellin, R.; Di Lizia, P.; Crepaldi, M.; Bernelli-Zazzera, F.; Ercoli Finzi, A.

    Rosetta is the third cornerstone mission of the European Space Agency scientific program "Horizon 2000". Rosetta will be the first spacecraft to orbit around a comet nucleus. It was launched in March 2004 and will reach the comet 67P/ChurymovGerasimenko in 2014. A lander (Philae) will be released and land on the comet surface for in-situ investigation. One of the key subsystems of the lander Philae is the Sampler, Drill and Distribution (SD2) subsystem. SD2 provides in-situ operations devoted to soil drilling, samples collection, and their distribution to two evolved gas analyzers (COSAC and PTOLEMY) and one imaging instrument (ÇIVA). Recent studies have proven the existence of a correlation between the drill behavior during perforation and the mechanical characteristics of the cometary soil. This outlines the possibility of using SD2 not only as a tool to support other instruments, but also as a scientific instrument itself. In this paper the possibility of using the drill as a quasi-static penetrator is presented. Within this approach, laboratory tests on glass-foam specimens of different porosity show that the drill behaviour during penetration can be exploited for cometary soil characterization.

  8. Multimodal segmentation of optic disc and cup from stereo fundus and SD-OCT images

    NASA Astrophysics Data System (ADS)

    Miri, Mohammad Saleh; Lee, Kyungmoo; Niemeijer, Meindert; Abràmoff, Michael D.; Kwon, Young H.; Garvin, Mona K.

    2013-03-01

    Glaucoma is one of the major causes of blindness worldwide. One important structural parameter for the diagnosis and management of glaucoma is the cup-to-disc ratio (CDR), which tends to become larger as glaucoma progresses. While approaches exist for segmenting the optic disc and cup within fundus photographs, and more recently, within spectral-domain optical coherence tomography (SD-OCT) volumes, no approaches have been reported for the simultaneous segmentation of these structures within both modalities combined. In this work, a multimodal pixel-classification approach for the segmentation of the optic disc and cup within fundus photographs and SD-OCT volumes is presented. In particular, after segmentation of other important structures (such as the retinal layers and retinal blood vessels) and fundus-to-SD-OCT image registration, features are extracted from both modalities and a k-nearest-neighbor classification approach is used to classify each pixel as cup, rim, or background. The approach is evaluated on 70 multimodal image pairs from 35 subjects in a leave-10%-out fashion (by subject). A significant improvement in classification accuracy is obtained using the multimodal approach over that obtained from the corresponding unimodal approach (97.8% versus 95.2%; p < 0:05; paired t-test).

  9. Triaxial- and uniaxial-compression testing methods developed for extraction of pore water from unsaturated tuff, Yucca Mountain, Nevada

    SciTech Connect

    Mower, T.E.; Higgins, J.D.; Yang, I.C.

    1989-12-31

    To support the study of hydrologic system in the unsaturated zone at Yucca Mountain, Nevada, two extraction methods were examined to obtain representative, uncontaminated pore-water samples from unsaturated tuff. Results indicate that triaxial compression, which uses a standard cell, can remove pore water from nonwelded tuff that has an initial moisture content greater than 11% by weight; uniaxial compression, which uses a specifically fabricated cell, can extract pore water from nonwelded tuff that has an initial moisture content greater than 8% and from welded tuff that has an initial moisture content greater than 6.5%. For the ambient moisture conditions of Yucca Mountain tuffs, uniaxial compression is the most efficient method of pore-water extraction. 12 refs., 7 figs., 2 tabs.

  10. Bioinspired electronic white cane implementation based on a LIDAR, a tri-axial accelerometer and a tactile belt.

    PubMed

    Pallejà, Tomàs; Tresanchez, Marcel; Teixidó, Mercè; Palacin, Jordi

    2010-01-01

    This work proposes the creation of a bioinspired electronic white cane for blind people using the whiskers principle for short-range navigation and exploration. Whiskers are coarse hairs of an animal's face that tells the animal that it has touched something using the nerves of the skin. In this work the raw data acquired from a low-size terrestrial LIDAR and a tri-axial accelerometer is converted into tactile information using several electromagnetic devices configured as a tactile belt. The LIDAR and the accelerometer are attached to the user's forearm and connected with a wire to the control unit placed on the belt. Early validation experiments carried out in the laboratory are promising in terms of usability and description of the environment. PMID:22163529

  11. Stability of triangular points in the photogravitational CR3BP with Poynting-Robertson drag and a smaller triaxial primary

    NASA Astrophysics Data System (ADS)

    Singh, Jagadish; Emmanuel, A. Balogun

    2014-09-01

    The stability of triangular equilibrium points in the framework of the circular restricted three-body problem (CR3BP) is investigated for a test particle of infinitesimal mass in the vicinity of two massive bodies (primaries), when the bigger primary is a source of radiation and the smaller one is a triaxial rigid body with one of the axes as the axis of symmetry and its equatorial plane coinciding with the plane of motion, under the Poynting-Robertson (P-R) drag effect as a result of the radiating primary. It is found that the involved parameters influence the position of triangular points and their linear stability. It is noted that these points are unstable in the presence of Poynting-Robertson drag effect and conditionally stable in the absence of it.

  12. Experimental Investigation of the Strain Rate Dependent Behaviour of 2D Biaxially and Triaxially Reinforced Braided Composites

    NASA Astrophysics Data System (ADS)

    Böhm, R.; Hornig, A.; Luft, J.; Becker, M.; Koch, I.; Grüber, B.; Hufenbach, W.

    2014-04-01

    The performance of 2D biaxially and triaxially reinforced braided carbon fibre composites under dynamic loading is evaluated in the presented study. The accurate manufacturing of tensile specimen made of braided sleeves is explained particularly with regard to efficiency and reproducibility. In order to determine reliable strain rate dependent properties, the high-speed testing procedure is discussed. Using five materials, the parameter identification is described and relevant material data is provided. The measured stiffnesses and strengths are used to predict the non-linear stress-strain behaviour with an earlier proposed phenomenological damage model for textile composites. The gained orthotropic property-profile provides the input parameters for a numerical analysis of braided composite components using the calibrated model.

  13. Child activity recognition based on cooperative fusion model of a triaxial accelerometer and a barometric pressure sensor.

    PubMed

    Nam, Yunyoung; Park, Jung Wook

    2013-03-01

    This paper presents a child activity recognition approach using a single 3-axis accelerometer and a barometric pressure sensor worn on a waist of the body to prevent child accidents such as unintentional injuries at home. Labeled accelerometer data are collected from children of both sexes up to the age of 16 to 29 months. To recognize daily activities, mean, standard deviation, and slope of time-domain features are calculated over sliding windows. In addition, the FFT analysis is adopted to extract frequency-domain features of the aggregated data, and then energy and correlation of acceleration data are calculated. Child activities are classified into 11 daily activities which are wiggling, rolling, standing still, standing up, sitting down, walking, toddling, crawling, climbing up, climbing down, and stopping. The overall accuracy of activity recognition was 98.43% using only a single- wearable triaxial accelerometer sensor and a barometric pressure sensor with a support vector machine. PMID:24235114

  14. Triaxial tunable mechanical monolithic sensors for large band low frequency monitoring and characterization of sites and structures

    NASA Astrophysics Data System (ADS)

    Barone, F.; Giordano, G.; Acernese, F.; Romano, R.

    2016-04-01

    This paper describes the application of the monolithic UNISA Folded Pendulum, optimized as inertial sensor (seismometer) for low frequency applications for characterization of sites (including underground sites) and structures (e.g. buildings, bridges, historical monuments), but, in general, for applications requiring large band low-frequency performances coupled with high sensitivities. The main characteristics of this class of sensors are high sensitivity, large measurement band, compactness, lightness, scalability, tunability of the resonance frequency, low thermal noise and very good immunity to environmental noises. The horizontal and vertical versions of folded pendulum allow an effective state-of-the-art mechanical implementation of triaxial sensors, configurable both as seismometer and/or as accelerometer.

  15. Bioinspired Electronic White Cane Implementation Based on a LIDAR, a Tri-Axial Accelerometer and a Tactile Belt

    PubMed Central

    Pallejà, Tomàs; Tresanchez, Marcel; Teixidó, Mercè; Palacin, Jordi

    2010-01-01

    This work proposes the creation of a bioinspired electronic white cane for blind people using the whiskers principle for short-range navigation and exploration. Whiskers are coarse hairs of an animal's face that tells the animal that it has touched something using the nerves of the skin. In this work the raw data acquired from a low-size terrestrial LIDAR and a tri-axial accelerometer is converted into tactile information using several electromagnetic devices configured as a tactile belt. The LIDAR and the accelerometer are attached to the user’s forearm and connected with a wire to the control unit placed on the belt. Early validation experiments carried out in the laboratory are promising in terms of usability and description of the environment. PMID:22163529

  16. The Evolution of the Globular Cluster System in a Triaxial Galaxy: Can a Galactic Nucleus Form by Globular Cluster Capture?

    NASA Astrophysics Data System (ADS)

    Capuzzo-Dolcetta, Roberto

    1993-10-01

    Among the possible phenomena inducing evolution of the globular cluster system in an elliptical galaxy, dynamical friction due to field stars and tidal disruption caused by a central nucleus is of crucial importance. The aim of this paper is the study of the evolution of the globular cluster system in a triaxial galaxy in the presence of these phenomena. In particular, the possibility is examined that some galactic nuclei have been formed by frictionally decayed globular clusters moving in a triaxial potential. We find that the initial rapid growth of the nucleus, due mainly to massive clusters on box orbits falling in a short time scale into the galactic center, is later slowed by tidal disruption induced by the nucleus itself on less massive clusters in the way described by Ostriker, Binney, and Saha. The efficiency of dynamical friction is such to carry to the center of the galaxy enough globular cluster mass available to form a compact nucleus, but the actual modes and results of cluster-cluster encounters in the central potential well are complicated phenomena which remains to be investigated. The mass of the resulting nucleus is determined by the mutual feedback of the described processes, together with the initial spatial, velocity, and mass distributions of the globular cluster family. The effect on the system mass function is studied, showing the development of a low- and high-mass turnover even with an initially flat mass function. Moreover, in this paper is discussed the possibility that the globular cluster fall to the galactic center has been a cause of primordial violent galactic activity. An application of the model to M31 is presented.

  17. Geology of the USW SD-7 drill hole Yucca Mountain, Nevada

    SciTech Connect

    Rautman, C.A.; Engstrom, D.A.

    1996-09-01

    The USW SD-7 drill hole is one of several holes drilled under Site Characterization Plan Study 8.3.1.4.3.1, also known as the Systematic Drilling Program, as part of the U.S. Department of Energy characterization program at Yucca Mountain, Nevada. The Yucca Mountain site has been proposed as the potential location of a repository for high-level nuclear waste. The SD-7 drill hole is located near the southern end of the potential repository area and immediately to the west of the Main Test Level drift of the Exploratory Studies Facility. The hole is not far from the junction of the Main Test Level drift and the proposed South Ramp decline. Drill hole USW SD-7 is 2675.1 ft (815.3 m) deep, and the core recovered nearly complete sections of ash-flow tuffs belonging to the lower half of the Tiva Canyon Tuff, the Pah Canyon Tuff, and the Topopah Spring Tuff, all of which are part of the Miocene Paintbrush Group. Core was recovered from much of the underlying Calico Hills Formation, and core was virtually continuous in the Prow Pass Tuff and the Bullfrog Tuff. The SD-7 drill hole penetrated the top several tens of feet into the Tram Tuff, which underlies the Prow Pass and Bullfrog Tuffs. These latter three units are all formations of the Crater Flat Group, The drill hole was collared in welded materials assigned to the crystal-poor middle nonlithophysal zone of the Tiva Canyon Tuff; approximately 280 ft (85 m) of this ash-flow sheet was penetrated by the hole. The Yucca Mountain Tuff appears to be missing from the section at the USW SD-7 location, and the Pah Canyon Tuff is only 14.5 ft thick. The Pah Canyon Tuff was not recovered in core because of drilling difficulties, suggesting that the unit is entirely nonwelded. The presence of this unit is inferred through interpretation of down-hole geophysical logs.

  18. 40 CFR Table 28 to Subpart G of... - Deck Seam Length Factors a (SD) for Internal Floating Roof Tanks

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 9 2011-07-01 2011-07-01 false Deck Seam Length Factors a (SD) for Internal Floating Roof Tanks 28 Table 28 to Subpart G of Part 63 Protection of Environment ENVIRONMENTAL... (SD) for Internal Floating Roof Tanks Deck construction Typical deck seam length factor...

  19. Complete Genome Sequence of Geobacter anodireducens SD-1T, a Salt-Tolerant Exoelectrogenic Microbe in Bioelectrochemical Systems.

    PubMed

    Sun, Dan; Cheng, Shaoan; Wang, Aijie; Huang, Fangliang; Liu, Wenzong; Xia, Xue

    2016-01-01

    Strain SD-1 is the type strain of the species Geobacter anodireducens, which was originally isolated from a microbial fuel cell reactor in the United States. The characteristic of this bacterium is its high electrochemical activity. Here, we report the fully assembled genome and plasmid sequence of G. anodireducens SD-1(T). PMID:27257213

  20. Complete Genome Sequence of Geobacter anodireducens SD-1T, a Salt-Tolerant Exoelectrogenic Microbe in Bioelectrochemical Systems

    PubMed Central

    Wang, Aijie; Huang, Fangliang; Liu, Wenzong; Xia, Xue

    2016-01-01

    Strain SD-1 is the type strain of the species Geobacter anodireducens, which was originally isolated from a microbial fuel cell reactor in the United States. The characteristic of this bacterium is its high electrochemical activity. Here, we report the fully assembled genome and plasmid sequence of G. anodireducens SD-1T. PMID:27257213

  1. 40 CFR Table 28 to Subpart G of... - Deck Seam Length Factors a (SD) for Internal Floating Roof Tanks

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 10 2012-07-01 2012-07-01 false Deck Seam Length Factors a (SD) for Internal Floating Roof Tanks 28 Table 28 to Subpart G of Part 63 Protection of Environment ENVIRONMENTAL... (SD) for Internal Floating Roof Tanks Deck construction Typical deck seam length factor...

  2. 40 CFR Table 28 to Subpart G of... - Deck Seam Length Factors a (SD) for Internal Floating Roof Tanks

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 10 2014-07-01 2014-07-01 false Deck Seam Length Factors a (SD) for Internal Floating Roof Tanks 28 Table 28 to Subpart G of Part 63 Protection of Environment ENVIRONMENTAL... (SD) for Internal Floating Roof Tanks Deck construction Typical deck seam length factor...

  3. 40 CFR Table 28 to Subpart G of... - Deck Seam Length Factors a (SD) for Internal Floating Roof Tanks

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 10 2013-07-01 2013-07-01 false Deck Seam Length Factors a (SD) for Internal Floating Roof Tanks 28 Table 28 to Subpart G of Part 63 Protection of Environment ENVIRONMENTAL... (SD) for Internal Floating Roof Tanks Deck construction Typical deck seam length factor...

  4. 40 CFR Table 28 to Subpart G of... - Deck Seam Length Factors a (SD) for Internal Floating Roof Tanks

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Deck Seam Length Factors a (SD) for Internal Floating Roof Tanks 28 Table 28 to Subpart G of Part 63 Protection of Environment ENVIRONMENTAL... (SD) for Internal Floating Roof Tanks Deck construction Typical deck seam length factor...

  5. Plasmodium falciparum Rosetting Epitopes Converge in the SD3-Loop of PfEMP1-DBL1α

    PubMed Central

    Angeletti, Davide; Albrecht, Letusa; Blomqvist, Karin; Quintana, María del Pilar; Akhter, Tahmina; Bächle, Susanna M.; Sawyer, Alan; Sandalova, Tatyana; Achour, Adnane; Wahlgren, Mats; Moll, Kirsten

    2012-01-01

    The ability of Plasmodium falciparum parasitized RBC (pRBC) to form rosettes with normal RBC is linked to the virulence of the parasite and RBC polymorphisms that weaken rosetting confer protection against severe malaria. The adhesin PfEMP1 mediates the binding and specific antibodies prevent sequestration in the micro-vasculature, as seen in animal models. Here we demonstrate that epitopes targeted by rosette disrupting antibodies converge in the loop of subdomain 3 (SD3) which connects the h6 and h7 α-helices of PfEMP1-DBL1α. Both monoclonal antibodies and polyclonal IgG, that bound to epitopes in the SD3-loop, stained the surface of pRBC, disrupted rosettes and blocked direct binding of recombinant NTS-DBL1α to RBC. Depletion of polyclonal IgG raised to NTS-DBL1α on a SD3 loop-peptide removed the anti-rosetting activity. Immunizations with recombinant subdomain 1 (SD1), subdomain 2 (SD2) or SD3 all generated antibodies reacting with the pRBC-surface but only the sera of animals immunized with SD3 disrupted rosettes. SD3-sequences were found to segregate phylogenetically into two groups (A/B). Group A included rosetting sequences that were associated with two cysteine-residues present in the SD2-domain while group B included those with three or more cysteines. Our results suggest that the SD3 loop of PfEMP1-DBL1α is an important target of anti-rosetting activity, clarifying the molecular basis of the development of variant-specific rosette disrupting antibodies. PMID:23227205

  6. Correlation between SD-OCT, immunocytochemistry and functional findings in an animal model of retinal degeneration

    PubMed Central

    Cuenca, Nicolás; Fernández-Sánchez, Laura; Sauvé, Yves; Segura, Francisco J.; Martínez-Navarrete, Gema; Tamarit, José Manuel; Fuentes-Broto, Lorena; Sanchez-Cano, Ana; Pinilla, Isabel

    2014-01-01

    Purpose: The P23H rhodopsin mutation is an autosomal dominant cause of retinitis pigmentosa (RP). The degeneration can be tracked using different anatomical and functional methods. In our case, we evaluated the anatomical changes using Spectral-Domain Optical Coherence Tomography (SD-OCT) and correlated the findings with retinal thickness values determined by immunocytochemistry.Methods: Pigmented rats heterozygous for the P23H mutation, with ages between P18 and P180 were studied. Function was assessed by means of optomotor testing and ERGs. Retinal thicknesses measurements, autofluorescence and fluorescein angiography were performed using Spectralis OCT. Retinas were studied by means of immunohistochemistry. Results: Between P30 and P180, visual acuity decreased from 0.500 to 0.182 cycles per degree (cyc/deg) and contrast sensitivity decreased from 54.56 to 2.98 for a spatial frequency of 0.089 cyc/deg. Only cone-driven b-wave responses reached developmental maturity. Flicker fusions were also comparable at P29 (42 Hz). Double flash-isolated rod-driven responses were already affected at P29. Photopic responses revealed deterioration after P29.A reduction in retinal thicknesses and morphological modifications were seen in OCT sections. Statistically significant differences were found in all evaluated thicknesses. Autofluorescence was seen in P23H rats as sparse dots. Immunocytochemistry showed a progressive decrease in the outer nuclear layer (ONL), and morphological changes. Although anatomical thickness measures were significantly lower than OCT values, there was a very strong correlation between the values measured by both techniques.Conclusions: In pigmented P23H rats, a progressive deterioration occurs in both retinal function and anatomy. Anatomical changes can be effectively evaluated using SD-OCT and immunocytochemistry, with a good correlation between their values, thus making SD-OCT an important tool for research in retinal degeneration. PMID:25565976

  7. A complex noise reduction method for improving visualization of SD-OCT skin biomedical images

    NASA Astrophysics Data System (ADS)

    Myakinin, Oleg O.; Zakharov, Valery P.; Bratchenko, Ivan A.; Kornilin, Dmitry V.; Khramov, Alexander G.

    2014-05-01

    In this paper we consider the original method of solving noise reduction problem for visualization's quality improvement of SD-OCT skin and tumors biomedical images. The principal advantages of OCT are high resolution and possibility of in vivo analysis. We propose a two-stage algorithm: 1) process of raw one-dimensional A-scans of SD-OCT and 2) remove a noise from the resulting B(C)-scans. The general mathematical methods of SD-OCT are unstable: if the noise of the CCD is 1.6% of the dynamic range then result distortions are already 25-40% of the dynamic range. We use at the first stage a resampling of A-scans and simple linear filters to reduce the amount of data and remove the noise of the CCD camera. The efficiency, improving productivity and conservation of the axial resolution when using this approach are showed. At the second stage we use an effective algorithms based on Hilbert-Huang Transform for more accurately noise peaks removal. The effectiveness of the proposed approach for visualization of malignant and benign skin tumors (melanoma, BCC etc.) and a significant improvement of SNR level for different methods of noise reduction are showed. Also in this study we consider a modification of this method depending of a specific hardware and software features of used OCT setup. The basic version does not require any hardware modifications of existing equipment. The effectiveness of proposed method for 3D visualization of tissues can simplify medical diagnosis in oncology.

  8. The Mysterious sdO X-ray Binary BD+37°442

    NASA Astrophysics Data System (ADS)

    Heber, U.; Geier, S.; Irrgang, A.; Schneider, D.; Barbu-Barna, I.; Mereghetti, S.; La Palombara, N.

    2014-04-01

    Pulsed X-ray emission in the luminous, helium-rich sdO BD +37°442 has recently been discovered (La Palombara et al. 2012). It was suggested that the sdO star has a neutron star or white dwarf companion with a spin period of 19.2 s. After HD 49798, which has a massive white dwarf companion spinning at 13.2 s in an 1.55 day orbit, this is only the second O-type subdwarf from which X-ray emission has been detected. We report preliminary results of our ongoing campaign to obtain time-resolved high-resolution spectroscopy using the CAFE instrument at Calar Alto observatory and SARG at the Telescopio Nationale Galileo. Atmospheric parameters were derived via a quantitative NLTE spectral analysis. The line fits hint at an unusually large projected rotation velocity. Therefore it seemed likely that BD +37°442 is a binary similar to HD 49798 and that the orbital period is also similar. The level of X-ray emission from BD +37°442 could be explained by accretion from the sdO wind by a neutron star orbiting at a period of less than ten days. Hence, we embarked on radial velocity monitoring in order to derive the binary parameters of the BD+37°442 system and obtained 41 spectra spread out over several month in 2012. Unlike for HD 49798, no radial velocity variations were found and, hence, there is no dynamical evidence for the existence of a compact companion yet. The origin of the pulsed X-ray emission remains as a mystery.

  9. The orbital periods of three sdB eclipsing binary systems

    NASA Astrophysics Data System (ADS)

    Kilkenny, D.

    2014-12-01

    Recent timings of eclipses made between 2011 and 2014 are presented for three binary systems with hot subdwarf primary stars, AA Dor, NY Vir and EC 10246-2707. In the case of AA Dor, the period remains constant. In NY Vir, a rapidly pulsating sdBVr with a cool companion, the period change now appears more complex than can be described by a simple quadratic. EC 10246-2707, which has previously appeared to have a constant period, now appears to be showing a significant period increase. The effect of gravitational radiation in HW Vir-like systems is briefly discussed.

  10. EXOTIME: Searching for planets and measuring \\dot{P} in sdB pulsators

    NASA Astrophysics Data System (ADS)

    Lutz, R.; Schuh, S.; Silvotti, R.

    2012-12-01

    We review the status of the EXOTIME project (EXOplanet search with the TIming MEthod). The two main goals of EXOTIME are to search for sub-stellar companions to sdB stars in wide orbits, and to measure the secular variation of the pulsation periods, which are related to the evolutionary change of the stellar structure. Now, after four years of dense monitoring, we start to see some results and present the brown dwarf and exoplanet candidates V1636 Ori b and DW Lyn b.

  11. HS 0705+6700: a New Eclipsing sdB Binary

    NASA Astrophysics Data System (ADS)

    Drechsel, H.; Heber, U.; Napiwotzki, R.; Ostensen, R.; Solheim, J.-E.; Deetjen, J.; Schuh, S.

    HS 0705+6700 is a newly discovered eclipsing sdB binary system consisting of an sdB primary and a cool secondary main sequence star. CCD photometry obtained in October and November 2000 with the 2.5m Nordic (NOT) telescope (La Palma, Tenerife) in the B passband and with the 2.2m Calar Alto telescope (CAFOS, R filter) yielded eclipse light curves with complete orbital phase coverage at high time resolution. A periodogram analysis of 12 primary minimum times distributed over the time span from October 2000 to March 2001 allowed to derive the following exact period and linear ephemeris: prim. min. = HJD 2451822.759782(22) + 0.09564665(39) ṡ E A total of 15 spectra taken with the 3.5m Calar Alto telescope (TWIN spectrograph) on March 11-12, 2001, were used to establish the radial velocity curve of the primary star (K1 = 85.8 km/s) , and to determine its basic atmospheric parameters (Teff = 29300 K, log g = 5.47). The B and R light curves were solved using our Wilson-Devinney based light curve analysis code MORO (Drechsel et al. 1995, A&A 294, 723). The best fit solution yielded exact system parameters consistent with the spectroscopic results. Detailed results will be published elsewhere (Drechsel et al. 2001, A&A, in preparation).

  12. SdH oscillations and pressure effect of the Weyl semimetal NbAs

    NASA Astrophysics Data System (ADS)

    Luo, Yongkang; Ghimire, N. J.; Wartenbe, M.; Choi, Hongchul; Neupane, M.; McDonald, R. D.; Bauer, E. D.; Zhu, Jianxin; Thompson, J. D.; Ronning, F.

    Via angular Shubnikov-de Hass (SdH) quantum oscillations measurements, we determine the Fermi surface topology of NbAs. The SdH oscillations consist of two frequencies, corresponding to two Fermi surface extrema: 20.8 T (α-pocket) and 15.6 T (β-pocket). The analysis shows that the β-pocket has a Berry phase of π and a small effective mass 0.033 m0, indicative of a nontrivial topology; whereas the α-pocket has a trivial Berry phase of 0 and a heavier effective mass 0.066 m0. Subtle changes can be seen in the ρxx(T) profiles with pressure up to 2.31 GPa. The Fermi surfaces undergo an anisotropic evolution under pressure, while the topological features of the two pockets remain unchanged. Specific heat measurements reveal a small Sommerfeld coefficient γ0 = 0.09(1) mJ/(molK2) and a large Debye temperature, ΘD = 450(9) K, confirming a ``hard'' crystalline lattice that is stable under pressure. We also studied the Kadowaki-Woods ratio of this low-carrier-density massless system, RKW = 3.2×104µ Ω cm mol2K2J-2. After accounting for the small carrier density in NbAs, this RKW indicates a suppressed transport scattering rate relative to other metals.

  13. SdH oscillations and pressure effect of the Weyl semimetal NbAs

    NASA Astrophysics Data System (ADS)

    Luo, Yongkang; Ghimire, N. J.; Wartenbe, M.; Choi, Hongchul; Neupane, M.; McDonald, R. D.; Bauer, E. D.; Zhu, Jianxin; Thompson, J. D.; Ronning, F.

    Via angular Shubnikov-de Hass (SdH) quantum oscillations measurements, we determine the Fermi surface topology of NbAs. The SdH oscillations consist of two frequencies: 20.8 T (α-pocket) and 15.6 T (β-pocket). The analysis shows that the β-pocket has a Berry phase of π and a small effective mass 0.033 m0, indicative of a nontrivial topology; whereas the α-pocket has a trivial Berry phase of 0 and a heavier effective mass 0.066 m0. Subtle changes can be seen in the ρxx(T) profiles with pressure up to 2.31 GPa. The Fermi surfaces undergo an anisotropic evolution under pressure, while the topological features of the two pockets remain unchanged. Specific heat measurements reveal a small Sommerfeld coefficient γ0 = 0.09(1) mJ/(molK2) and a large Debye temperature, ΘD = 450(9) K, confirming a ``hard'' crystalline lattice. The Kadowaki-Woods ratio and a suppressed transport scattering rate are also studied.

  14. The role of glutathione detoxification pathway in MCLR-induced hepatotoxicity in SD rats.

    PubMed

    Li, Shangchun; Chen, Jun; Xie, Ping; Guo, Xiaochun; Fan, Huihui; Yu, Dezhao; Zeng, Cheng; Chen, Liang

    2015-12-01

    In the present study, we investigated the role of glutathione (GSH) and its related enzymes in Sprague Dawley (SD) rats subjected to microcystin-leucine-arginine (MCLR)-induced hepatotoxicity. SD rats were intraperitoneally (i.p.) injected with MCLR after pretreating with or without buthionine-(S,R)-sulfoximine (BSO), an inhibitor of GSH synthesis. The depletion of GSH with BSO enhanced MCLR-induced oxidative stress, resulting in more severe liver damage and higher MCLR accumulation. Similarly, the contents of malondialdehyde (MDA), total GSH (T-GSH), oxidized GSH (GSSG) and GSH were significantly enhanced in BSO pretreated rats following MCLR treatment. The study showed that the transcription of GSH-related enzymes such as glutathione-S-transferase (GST), γ-glutamylcysteine synthetase (γ-GCS), glutathione reductase (GR) varied in different ways (expect for glutathione peroxidase (GPx), whose gene expression was induced in all treated groups) with or without BSO pretreatment before MCLR exposure, suggesting an adaptative response of GSH-related enzymes at transcription level to combat enhancement of oxidative stress induced by MCLR when pretreated with BSO. These data suggested the tissues with low GSH concentration are highly vulnerable to MCLR toxicity and GSH was critical for the detoxification in MCLR-induced hepatotoxicity in vivo. PMID:24964298

  15. FUV, UV, and Optical Observations of the He-sdO Star BD+39 3226

    NASA Astrophysics Data System (ADS)

    Chayer, Pierre; Green, E. M.; Fontaine, G.

    2014-01-01

    Based on observations carried out with the Far Ultraviolet Spectroscopic Explorer, the Space Telescope Imaging Spectrograph, the MMT Observatory, and the Keck telescope HIRES spectrograph, we present a spectral analysis of the He-sdO star BD+39 3226. By fitting the MMT spectrum we obtain a gravity that is 0.7 dex higher than the one reported in the literature. The new atmospheric parameters will have an impact on the measurement of the HI column density toward BD+39 3226, and by this very fact on the deuterium abundance. The high-resolution spectra show stellar absorption lines coming from C, N, O, Si, P, S, Fe, and Ni. The spectra also show lines from heavy elements such as Ge, As, and Sn. On the other hand, neither Zr nor Pb absorption lines are detected. The non-detection of lead in BD+39 3226 indicates that the star does not belong to the newly discovered group of lead-rich He-sdO stars. P.C. is supported by the Canadian Space Agency under a Public Works and Government Services of Canada contract.

  16. A framework for classification and segmentation of branch retinal artery occlusion in SD-OCT

    NASA Astrophysics Data System (ADS)

    Guo, Jingyun; Shi, Fei; Zhu, Weifang; Chen, Haoyu; Chen, Xinjian

    2016-03-01

    Branch retinal artery occlusion (BRAO) is an ocular emergency which could lead to blindness. Quantitative analysis of BRAO region in the retina is very needed to assessment of the severity of retinal ischemia. In this paper, a fully automatic framework was proposed to classify and segment BRAO based on 3D spectral-domain optical coherence tomography (SD-OCT) images. To the best of our knowledge, this is the first automatic 3D BRAO segmentation framework. First, a support vector machine (SVM) based classifier is designed to differentiate BRAO into acute phase and chronic phase, and the two types are segmented separately. To segment BRAO in chronic phase, a threshold-based method is proposed based on the thickness of inner retina. While for segmenting BRAO in acute phase, a two-step segmentation is performed, which includes the bayesian posterior probability based initialization and the graph-search-graph-cut based segmentation. The proposed method was tested on SD-OCT images of 23 patients (12 of acute and 11 of chronic phase) using leave-one-out strategy. The overall classification accuracy of SVM classifier was 87.0%, and the TPVF and FPVF for acute phase were 91.1%, 5.5%; for chronic phase were 90.5%, 8.7%, respectively.

  17. Geology of the USW SD-9 drill hole, Yucca Mountain, Nevada

    SciTech Connect

    Engstrom, D.A.; Rautman, C.A.

    1996-10-01

    Drill hole USW SD-9 is one of several holes drilled under Site Characterization Plan Study as part of the characterization program at Yucca Mountain, Nevada, which has been proposed as the potential location of a repository for high-level nuclear waste. The SD-9 drill hole is located in the northern part of the potential repository area. Quantitative and semiquantitative data are included in this report for cover recovery, rock-quality designation (RQD), lithophysal cavity abundance, and fracturing. These data are spatially variable, both within and among the major formational-level stratigraphic units. Nonwelded intervals in general exhibit higher recoveries and more intact (higher) RQD values than welded intervals. The most intact, highest-RQD materials encountered within the Topopah Spring belong to the lower 33.3 ft of the middle nonlithophysal zone. This report includes quantitative data for the framework material properties of porosity, bulk and particle density, and saturated hydraulic conductivity. Graphical analysis of variations in these laboratory hydrologic properties indicates first-order control of material properties by the degree of welding and the presence of zeolite minerals. Many major lithostratigraphic contacts are not well expressed in the material-property profiles; contacts of material-property units are related more to changes in the intensity of welding. Approximate in-situ saturation data of samples preserved immediately upon recovery from the hole are included in the data tabulation.

  18. Single particle calculations for a Woods-Saxon potential with triaxial deformations, and large Cartesian oscillator basis

    NASA Astrophysics Data System (ADS)

    Mohammed-Azizi, B.; Medjadi, D. E.

    2004-01-01

    We present a computer program which solves the Schrodinger equation of the stationary states for an average nuclear potential of Woods-Saxon type. In this work, we take specifically into account triaxial (i.e. ellipsoidal) nuclear surfaces. The deformation is specified by the usual Bohr parameters. The calculations are carried out in two stages. In the first, one calculates the representative matrix of the Hamiltonian in the Cartesian oscillator basis. In the second stage one diagonalizes this matrix with the help of subroutines of the Eispack library. If it is wished, one can calculate all eigenvalues, or only the part of the eigenvalues that are contained in a fixed interval defined in advance. In this latter case the eigenvectors are given conjointly. The program is very rapid, and the run-time is mainly used for the diagonalization. Thus, it is possible to use a significant number of the basis states in order to insure a best convergence of the results. Program summaryProgram obtainable from:CPC Program Library, Queen's University of Belfast, N. Ireland Title of program:Triaxial Catalogue number:ADSK Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADSK Licensing provisions:None Computer:PC. AMD Athlon 1000 MHz Hard disk:40 Go Ram:256 Mo Swap file:4 Go Operating system:WINDOWS XP Software used:Microsoft Visual Fortran 5.0A (with full optimizations in the settings project options) Programming language:Fortran 77/90 (double precision) Number of bits in a word:32 Number of lines:7662 No. of bytes in distributed program, including test data, etc.:174 601 Distribution format:tar gzip file Nature of the problem: The single particle energies and the single particle wave functions are calculated from one-body Hamiltonian including a central field of Woods-Saxon type, a spin-orbit interaction, and the Coulomb potential for the protons. We consider only ellipsoidal (triaxial) shapes. The deformation of the nuclear shape is fixed by the usual Bohr parameters ( β,

  19. Single particle calculations for a Woods Saxon potential with triaxial deformations, and large Cartesian oscillator basis (new version code)

    NASA Astrophysics Data System (ADS)

    Mohammed-Azizi, B.; Medjadi, D. E.

    2007-05-01

    We present a new version of the computer program which solves the Schrödinger equation of the stationary states for an average nuclear potential of Woods-Saxon type. In this work, we take specifically into account triaxial (i.e. ellipsoidal) nuclear surfaces. The deformation is specified by the usual Bohr parameters. The calculations are carried out in two stages. In the first, one calculates the representative matrix of the Hamiltonian in the Cartesian oscillator basis. In the second stage one diagonalizes this matrix with the help of subroutines of the EISPACK library. This new version calculates all the eigenvalues up to a given cutoff energy, and gives the components of the corresponding eigenfunctions. For a more convenient handling, these results are stored simultaneously in the computer memory, and on a files. Program summaryTitle of program:Triaxial2007 Catalogue identifier:ADSK_v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADSK_v2_0 Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Summary of revision:One input file instead two. Reduced number of input parameters. Storage of eigenvalues and eigenvectors in memory in a very simple way which makes the code very convenient to the user. Reasons for the new version: More convenient handling of the eigenvectors Catalogue number old version: ADSK Catalogue number new version:ADSK_v2_0 Journal: Computer Physics Commun. 156 (2004) 241-282 Licensing provisions: none Computer: PC Pentium 4, 2600 MHz Hard disk: 40 Gb RAM: 256 Mb Swap file: 4 Gb Operating system: WINDOWS XP Software used: Compaq Visual FORTRAN (with full optimizations in the settings project options) Programming language used:Fortran 77/90 (double precision) Number of bits in a word: 32 No. of lines in distributed program, including test data, etc.:4058 No. of bytes in distributed program, including test data, etc.:75 590 Distribution format:tar.gz Nature of the problem: The single particle energies

  20. Global shear velocity heterogeneities in the D″ layer: Inversion from Sd-SKS differential travel times

    NASA Astrophysics Data System (ADS)

    Kuo, Ban-Yuan; Wu, Kuan-Yi

    1997-06-01

    A global map of shear velocity in the D″ layer results from the inversion of 340 differential travel times of diffracted S(SH) minus SKS(SV) (Sd-SKS), from long-period records of global seismic networks. The two-phase design reduces contamination from upper mantle heterogeneities and errors in location and origin time of the events. Additional corrections are made for (1) azimuthal anisotropy at stations where shear wave splitting parameters are available and for (2) travel time perturbations due to lower mantle asphericity, although both effects are minor compared with the observed residuals with respect to the preliminary reference Earth model (PREM) [Dziewonski and Anderson, 1981]. The corrected residuals, ranging from -16 to 18 s, are attributed to anomalies in D″ sampled by both phases. Taking these residuals as data and assuming a constant, 250-km-thick D″ layer, we invert for a lateral velocity variation model of D″ using spherical harmonics. In parameterizing D″ velocities, a high degree expansion (L=14) avoids aliasing, but only the reliably determined, low degree components (LI

  1. 3D Anisotropic Velocity Tomography of a Water Saturated Rock under True-Triaxial Stress in the Laboratory

    NASA Astrophysics Data System (ADS)

    Ghofrani Tabari, M.; Goodfellow, S. D.; Nasseri, M. B.; Young, R.

    2013-12-01

    A cubic specimen of water saturated Fontainebleau Sandstone is tested in the laboratory under true-triaxial loading where three different principal stresses are applied under drained conditions. Due to the loading arrangement, closure and opening of the pre-existing cracks in the rock, as well as creation and growth of the aligned cracks cause elliptical anisotropy and distributed heterogeneities. A Geophysical Imaging Cell equipped with an Acoustic Emission monitoring system is employed to image velocity structure of the sample during the experiment through repeated transducer to transducer non-destructive ultrasonic surveys. Apparent P-wave velocities along the rock body are calculated in different directions and shown in stereonet plots which demonstrate an overall anisotropy of the sample. The apparent velocities in the main three orthogonal cubic directions are used as raw data for building a mean spatial distribution model of anisotropy ratios. This approach is based on the concept of semi-principal axes in an elliptical anisotropic model and appointing two ratios between the three orthogonal velocities in each of the cubic grid cells. The spatial distribution model of anisotropy ratios are used to calculate the anisotropic ray-path segment matrix elements (Gij). These contain segment lengths of the ith ray in the jth cell in three dimensions where, length of each ray in each cell is computed for one principal direction based on the dip and strike of the ray and these lengths differ from the ones in an isotropic G Matrix. 3D strain of the squeezed rock and the consequent geometrical deformation is also included in the ray-path segment matrix. A Singular Value Decomposition (SVD) method is used for inversion from the data space of apparent velocities to the model space of P-wave propagation velocities in the three principal directions. Finally, spatial variation and temporal evolution of induced damages in the rock, representing uniformly distributed or

  2. Physical properties of the ESA Rosetta target asteroid (21) Lutetia. I. The triaxial ellipsoid dimensions, rotational pole, and bulk density

    NASA Astrophysics Data System (ADS)

    Drummond, J. D.; Conrad, A.; Merline, W. J.; Carry, B.; Chapman, C. R.; Weaver, H. A.; Tamblyn, P. M.; Christou, J. C.; Dumas, C.

    2010-11-01

    Context. Asteroid (21) Lutetia was the target of the ESA Rosetta mission flyby in 2010 July. Aims: We seek the best size estimates of the asteroid, the direction of its spin axis, and its bulk density, assuming its shape is well described by a smooth featureless triaxial ellipsoid. We also aim to evaluate the deviations from this assumption. Methods: We derive these quantities from the outlines of the asteroid in 307 images of its resolved apparent disk obtained with adaptive optics (AO) at Keck II and VLT, and combine these with recent mass determinations to estimate a bulk density. Results: Our best triaxial ellipsoid diameters for Lutetia, based on our AO images alone, are a × b × c = 132 × 101 × 93 km, with uncertainties of 4 × 3 × 13 km including estimated systematics, with a rotational pole within 5° of ECJ2000 [λβ] = [45° - 7°] , or EQJ2000 [RA Dec] = [44° + 9°] . The AO model fit itself has internal precisions of 1 × 1 × 8 km, but it is evident both from this model derived from limited viewing aspects and the radius vector model given in a companion paper, that Lutetia significantly departs from an idealized ellipsoid. In particular, the long axis may be overestimated from the AO images alone by about 10 km. Therefore, we combine the best aspects of the radius vector and ellipsoid model into a hybrid ellipsoid model, as our final result, of diameters 124 ± 5 × 101 ± 4 × 93 ± 13 km that can be used to estimate volumes, sizes, and projected areas. The adopted pole position is within 5° of [λβ] = [52° - 6°] or [RA Dec] = [52° + 12°]. Conclusions: Using two separately determined masses and the volume of our hybrid model, we estimate a density of 3.5±1.1 or 4.3±0.8 g cm-3. From the density evidence alone, we argue that this favors an enstatite-chondrite composition, although other compositions are formally allowed at the extremes (low-porosity CV/CO carbonaceous chondrite or high-porosity metallic). We discuss this in the context of

  3. Tri-Axial Accelerometer-Determined Daily Physical Activity and Sedentary Behavior of Suburban Community-Dwelling Older Japanese Adults

    PubMed Central

    Chen, Tao; Narazaki, Kenji; Honda, Takanori; Chen, Sanmei; Haeuchi, Yuki; Nofuji, Yu Y; Matsuo, Eri; Kumagai, Shuzo

    2015-01-01

    Knowledge regarding accelerometer-derived physical activity (PA) and sedentary behavior (SED) levels is scarce for Japanese older adults. The aims of this study were therefore to 1) describe levels of PA and SED in Japanese community-dwelling older adults, using tri-axial accelerometer; 2) examine the variation of PA and SED with respect to sex, age, and body mass index (BMI). Participants of this study were from the baseline survey of the Sasaguri Genkimon Study, who were 65 years or older and not certified as those requiring long-term care. PA was assessed objectively for seven consecutive days using tri-axial accelerometer. A total of 1,739 participants (median age: 72 years, men: 38.0%) with valid PA data were included. Overall, participants in the present study spent 54.5% of their waking time being sedentary and 45.5% being active, of which 5.4% was moderate-to-vigorous physical activity (MVPA). Women accumulated more minutes of light physical activity (LPA) and MVPA compared with men. In contrast, men spent more time being sedentary. Mean steps per day did not differ between sexes. Furthermore, participants with higher BMI (BMI ≥25) had lower PA levels, and longer SED compared with those with lower BMI (BMI <). PA levels were lower and SED was longer with age. The present study is the first to demonstrate that the levels of PA and SED differed by sex, age, and BMI in Japanese community-dwelling older adults. In particular, women were more active compared with men, providing unique insight into the current level of PA in older adults. Data presented in the study will enable further investigation of additional determinants of PA and SED in order to develop effective population-based intervention strategies to promote PA and reduce prolonged SED in the Japanese population and possibly other rapidly aging societies. Key points Accelerometer, that is capable to assess PA more precisely in large scale epidemiological studies, provides opportunity for improving

  4. Vector magnetometer design study: Analysis of a triaxial fluxgate sensor design demonstrates that all MAGSAT Vector Magnetometer specifications can be met

    NASA Technical Reports Server (NTRS)

    Adams, D. F.; Hartmann, U. G.; Lazarow, L. L.; Maloy, J. O.; Mohler, G. W.

    1976-01-01

    The design of the vector magnetometer selected for analysis is capable of exceeding the required accuracy of 5 gamma per vector field component. The principal elements that assure this performance level are very low power dissipation triaxial feedback coils surrounding ring core flux-gates and temperature control of the critical components of two-loop feedback electronics. An analysis of the calibration problem points to the need for improved test facilities.

  5. A non-uniform three-gap buncher cavity with suppression of transverse-electromagnetic mode leakage in the triaxial klystron amplifier

    SciTech Connect

    Qi, Zumin; Zhang, Jun Zhong, Huihuang; Zhu, Danni; Qiu, Yongfeng

    2014-01-15

    The triaxial klystron amplifier is an efficient high power relativistic klystron amplifier operating at high frequencies due to its coaxial structure with large radius. However, the coaxial structures result in coupling problems among the cavities as the TEM mode is not cut-off in the coaxial tube. Therefore, the suppression of the TEM mode leakage, especially the leakage from the buncher cavity to the input cavity, is crucial in the design of a triaxial klystron amplifier. In this paper, a non-uniform three-gap buncher cavity is proposed to suppress the TEM mode leakage. The cold cavity analysis shows that the non-uniform three-gap buncher cavity can significantly suppress the TEM mode generation compared to a uniform three-gap buncher cavity. Particle-in-cell simulation shows that the power leakage to the input cavity is less than 1.5‰ of the negative power in the buncher cavity and the buncher cavity can efficiently modulate an intense relativistic electron beam free of self-oscillations. A fundamental current modulation depth of 117% is achieved by employing the proposed non-uniform buncher cavity into an X-band triaxial amplifier, which results in the high efficiency generation of high power microwave.

  6. THE ROMER DELAY AND MASS RATIO OF THE sdB+dM BINARY 2M 1938+4603 FROM KEPLER ECLIPSE TIMINGS

    SciTech Connect

    Barlow, Brad N.; Wade, Richard A.; Liss, Sandra E.

    2012-07-10

    The eclipsing binary system 2M 1938+4603 consists of a pulsating hot subdwarf B star and a cool M dwarf companion in an effectively circular three-hour orbit. The light curve shows both primary and secondary eclipses, along with a strong reflection effect from the cool companion. Here, we present constraints on the component masses and eccentricity derived from the Romer delay of the secondary eclipse. Using six months of publicly available Kepler photometry obtained in short-cadence mode, we fit model profiles to the primary and secondary eclipses to measure their centroid values. We find that the secondary eclipse arrives on average 2.06 {+-} 0.12 s after the midpoint between primary eclipses. Under the assumption of a circular orbit, we calculate from this time delay a mass ratio of q = 0.2691 {+-} 0.0018 and individual masses of M{sub sd} = 0.372 {+-} 0.024 M{sub Sun} and M{sub c} = 0.1002 {+-} 0.0065 M{sub Sun} for the sdB and M dwarf, respectively. These results differ slightly from those of a previously published light-curve modeling solution; this difference, however, may be reconciled with a very small eccentricity, ecos {omega} Almost-Equal-To 0.00004. We also report a decrease in the orbital period of P-dot = (-1.23 {+-} 0.07) Multiplication-Sign 10{sup -10}.

  7. Unified framework for triaxial accelerometer-based fall event detection and classification using cumulants and hierarchical decision tree classifier

    PubMed Central

    Kambhampati, Satya Samyukta; Singh, Vishal; Ramkumar, Barathram

    2015-01-01

    In this Letter, the authors present a unified framework for fall event detection and classification using the cumulants extracted from the acceleration (ACC) signals acquired using a single waist-mounted triaxial accelerometer. The main objective of this Letter is to find suitable representative cumulants and classifiers in effectively detecting and classifying different types of fall and non-fall events. It was discovered that the first level of the proposed hierarchical decision tree algorithm implements fall detection using fifth-order cumulants and support vector machine (SVM) classifier. In the second level, the fall event classification algorithm uses the fifth-order cumulants and SVM. Finally, human activity classification is performed using the second-order cumulants and SVM. The detection and classification results are compared with those of the decision tree, naive Bayes, multilayer perceptron and SVM classifiers with different types of time-domain features including the second-, third-, fourth- and fifth-order cumulants and the signal magnitude vector and signal magnitude area. The experimental results demonstrate that the second- and fifth-order cumulant features and SVM classifier can achieve optimal detection and classification rates of above 95%, as well as the lowest false alarm rate of 1.03%. PMID:26609414

  8. Understanding differences between healthy swallows and penetration-aspiration swallows via compressive sensing of tri-axial swallowing accelerometry signals

    NASA Astrophysics Data System (ADS)

    Sejdić, Ervin; Dudik, Joshua M.; Kurosu, Atsuko; Jestrović, Iva; Coyle, James L.

    2014-05-01

    Swallowing accelerometry is a promising tool for non-invasive assessment of swallowing difficulties. A recent contribution showed that swallowing accelerometry signals for healthy swallows and swallows indicating laryn- geal penetration or tracheal aspiration have different time-frequency structures, which may be problematic for compressive sensing schemes based on time-frequency dictionaries. In this paper, we examined the effects of dif- ferent swallows on the accuracy of a compressive sensing scheme based on modulated discrete prolate spheroidal sequences. We utilized tri-axial swallowing accelerometry signals recorded from four patients during routinely schedule videofluoroscopy exams. In particular, we considered 77 swallows approximately equally distributed between healthy swallows and swallows presenting with some penetration/aspiration. Our results indicated that the swallow type does not affect the accuracy of a considered compressive sensing scheme. Also, the results con- firmed previous findings that each individual axis contributes different information. Our findings are important for further developments of a device which is to be used for long-term monitoring of swallowing difficulties.

  9. Inversion of sparse photometric data of asteroids using triaxial ellipsoid shape models and a Lommel-Seeliger scattering law

    NASA Astrophysics Data System (ADS)

    Cellino, A.; Muinonen, K.; Hestroffer, D.; Carbognani, A.

    2015-12-01

    The inversion of sparse photometric data of asteroids to derive from them information about the spin and shape properties of the objects is a hot topic in the era of the Gaia space mission. We have used a rigorous analytical treatment of the Lommel-Seeliger light-scattering law computed for the particular case of bodies having the shapes of ideal triaxial ellipsoids, and we have implemented this in the software developed for the treatment of Gaia photometric data for asteroids. In a set of numerical simulations, the performances of the photometry inversion code improve significantly with respect to the case in which purely geometric scattering is taken into account. When applied to real photometric data of asteroids obtained in the past by the Hipparcos satellite, however, we do not see any relevant improvement of the performances, due to the poor accuracy of these measurements. These results suggest that the role played by the light-scattering properties of asteroid surfaces is indeed relevant. On the other hand, any refined treatment of light-scattering effects cannot improve the reliability of photometric inversion when the quantity and quality of available data are much worse than what we expect to obtain from Gaia.

  10. Electromagnetic scattering by a triaxial homogeneous penetrable ellipsoid: Low-frequency derivation and testing of the localized nonlinear approximation

    NASA Astrophysics Data System (ADS)

    Perrusson, G.; Lambert, M.; Lesselier, D.; Charalambopoulos, A.; Dassios, G.

    2000-03-01

    The field resulting from the illumination by a localized time-harmonic low-frequency source (typically a magnetic dipole) of a voluminous lossy dielectric body placed in a lossy dielectric embedding is determined within the framework of the localized nonlinear approximation by means of a low-frequency Rayleigh analysis. It is sketched (1) how one derives a low-frequency series expansion in positive integral powers of (jk), where k is the embedding complex wavenumber, of the depolarization dyad that relates the background electric field to the total electric field inside the body; (2) how this expansion is used to determine the magnetic field resulting outside the body and how the corresponding series expansion of this field, up to the power 5 in (jk), follows once the series expansion of the incident electric field in the body volume is known up to the same power; and (3) how the needed nonzero coefficients of the depolarization dyad (up to the power 3 in (jk)) are obtained, for a general triaxial ellipsoid and after careful reduction for the geometrically degenerate geometries, with the help of the elliptical harmonic theory. Numerical results obtained by this hybrid low-frequency approach illustrate its capability to provide accurate magnetic fields at low computational cost, in particular, in comparison with a general purpose method-of-moments code.

  11. Experimental Techniques for Evaluating the Effects of Aging on Impact and High Strain Rate Properties of Triaxial Braided Composite Materials

    NASA Technical Reports Server (NTRS)

    Pereira, J. Michael; Roberts, Gary D.; Ruggeri, Charles R.; Gilat, Amos; Matrka, Thomas

    2010-01-01

    An experimental program is underway to measure the impact and high strain rate properties of triaxial braided composite materials and to quantify any degradation in properties as a result of thermal and hygroscopic aging typically encountered during service. Impact tests are being conducted on flat panels using a projectile designed to induce high rate deformation similar to that experienced in a jet engine fan case during a fan blade-out event. The tests are being conducted on as-fabricated panels and panels subjected to various numbers of aging cycles. High strain rate properties are being measured using a unique Hopkinson bar apparatus that has a larger diameter than conventional Hopkinson bars. This larger diameter is needed to measure representative material properties because of the large unit cell size of the materials examined in this work. In this paper the experimental techniques used for impact and high strain rate testing are described and some preliminary results are presented for both as-fabricated and aged composites.

  12. Unified framework for triaxial accelerometer-based fall event detection and classification using cumulants and hierarchical decision tree classifier.

    PubMed

    Kambhampati, Satya Samyukta; Singh, Vishal; Manikandan, M Sabarimalai; Ramkumar, Barathram

    2015-08-01

    In this Letter, the authors present a unified framework for fall event detection and classification using the cumulants extracted from the acceleration (ACC) signals acquired using a single waist-mounted triaxial accelerometer. The main objective of this Letter is to find suitable representative cumulants and classifiers in effectively detecting and classifying different types of fall and non-fall events. It was discovered that the first level of the proposed hierarchical decision tree algorithm implements fall detection using fifth-order cumulants and support vector machine (SVM) classifier. In the second level, the fall event classification algorithm uses the fifth-order cumulants and SVM. Finally, human activity classification is performed using the second-order cumulants and SVM. The detection and classification results are compared with those of the decision tree, naive Bayes, multilayer perceptron and SVM classifiers with different types of time-domain features including the second-, third-, fourth- and fifth-order cumulants and the signal magnitude vector and signal magnitude area. The experimental results demonstrate that the second- and fifth-order cumulant features and SVM classifier can achieve optimal detection and classification rates of above 95%, as well as the lowest false alarm rate of 1.03%. PMID:26609414

  13. Recognition of elementary arm movements using orientation of a tri-axial accelerometer located near the wrist.

    PubMed

    Biswas, Dwaipayan; Corda, Daniele; Baldus, Giovanni; Cranny, Andy; Maharatna, Koushik; Achner, Josy; Klemke, Jasmin; Jöbges, Michael; Ortmann, Steffen

    2014-09-01

    In this paper we present a method for recognising three fundamental movements of the human arm (reach and retrieve, lift cup to mouth, rotation of the arm) by determining the orientation of a tri-axial accelerometer located near the wrist. Our objective is to detect the occurrence of such movements performed with the impaired arm of a stroke patient during normal daily activities as a means to assess their rehabilitation. The method relies on accurately mapping transitions of predefined, standard orientations of the accelerometer to corresponding elementary arm movements. To evaluate the technique, kinematic data was collected from four healthy subjects and four stroke patients as they performed a number of activities involved in a representative activity of daily living, 'making-a-cup-of-tea'. Our experimental results show that the proposed method can independently recognise all three of the elementary upper limb movements investigated with accuracies in the range 91-99% for healthy subjects and 70-85% for stroke patients. PMID:25119720

  14. A microcomputer-based data acquisition and control system for the direct shear, ring shear, triaxial shear, and consolidation tests

    USGS Publications Warehouse

    Powers, Philip S.

    1983-01-01

    This report is intended to provide internal documentation for the U.S. Geological Survey laboratory's automatic data acquisition system. The operating procedures for each type of test are designed to independently lead a first-time user through the various stages of using the computer to control the test. Continuing advances in computer technology and the availability of desktop microcomputers with a wide variety of peripheral equipment at a reasonable cost can create an efficient automated geotechnical testing environment. A geotechnical testing environment is shown in figure 1. Using an automatic data acquisition system, laboratory test data from a variety of sensors can be collected, and manually or automatically recorded on a magnetic device at the same apparent time. The responses of a test can be displayed graphically on a CRT in a matter of seconds, giving the investigator an opportunity to evaluate the test data, and to make timely, informed decisions on such matters as whether to continue testing, abandon a test, or modify procedures. Data can be retrieved and results reported in tabular form, or graphic plots, suitable for publication. Thermistors, thermocouples, load cells, pressure transducers, and linear variable differential transformers are typical sensors which are incorporated in automated systems. The geotechnical tests which are most practical to automate are the long-term tests which often require readings to be recorded outside normal work hours and on weekends. Automation applications include incremental load consolidation tests, constant-rate-of-strain consolidation tests, direct shear tests, ring shear tests, and triaxial shear tests.

  15. A comparison of automatic fall detection by the cross-product and magnitude of tri-axial acceleration.

    PubMed

    Chao, Pei-Kuang; Chan, Hsiao-Lung; Tang, Fuk-Tan; Chen, Yu-Chuan; Wong, May-Kuen

    2009-10-01

    Falling is an important problem in the health maintenance of people above middle age. Portable accelerometer systems have been designed to detect falls. However, false alarms induced by some dynamic motions, such as walking and jumping, are difficult to avoid. Acceleration cross-product (AC)-related methods are proposed and examined by this study to seek solutions for detecting falls with less motion-evoked false alarms. A set of tri-axial acceleration data is collected during simulated falls, posture transfers and dynamic activities by wireless sensors for making methodological comparisons. The performance of fall detection is evaluated in aspects of parameter comparison, threshold selection, sensor placement and post-fall posture (PP) recruitment. By parameter comparison, AC leads to a larger area under the receiver operating characteristic (ROC) curve than acceleration magnitude (AM). Three strategies of threshold selection, for 100% sensitivity (Sen100), for 100% specificity (Spe100) and for the best sum (BS) of sensitivity and specificity, are evaluated. Selecting a threshold based on Sen100 and BS leads to more practicable results. Simultaneous data recording from sensors in the chest and waist is performed. Fall detection based on the data from the chest shows better global accuracy. PP recruitment leads to lower false alarm ratios (FR) for both AC- and AM-based methods. PMID:19713595

  16. Numerical Analysis of Free-Edge Effect on Size-Influenced Mechanical Properties of Single-Layer Triaxially Braided Composites

    NASA Astrophysics Data System (ADS)

    Zhang, Chao; Binienda, Wieslaw K.

    2014-12-01

    The mechanical properties of triaxially braided composites under transverse loads are found to be size-dependent, due to the presence of free-edge effect. Numerical studies of the mechanical behaviors of straight-sided coupon specimens and an infinitely large plate under both axial and transverse tension loads were conducted using a meso-scale finite element model. The numerical model correlates well with experimental results, successfully capturing the free-edge warping phenomena under transverse tension. Free-edge effect is observed as out-of-plane warping, and it can be correlated to the premature damage initiation in the affected area. The numerical results characterize the impact of free-edge effects on the global stress-strain response and local failure mechanisms. By conducting dimensional analysis, the relationships of effective stiffness and strength against specimen width are quantified using Weibull equations. The results of this study indicate that the free-edge effect is an inherent behavior of braided architecture. The free-edge effect produces significantly reduced transverse tension modulus and strength measurements.

  17. Important operational parameters of membrane bioreactor-sludge disintegration (MBR-SD) system for zero excess sludge production.

    PubMed

    Yoon, Seong-Hoon

    2003-04-01

    In order to prevent excess sludge production during wastewater treatment, a membrane bioreactor-sludge disintegration (MBR-SD) system has been introduced, where the disintegrated sludge is recycled to the bioreactor as a feed solution. In this study, a mathematical model was developed by incorporating a sludge disintegration term into the conventional activated sludge model and the relationships among the operational parameters were investigated. A new definition of F/M ratio for the MBR-SD system was suggested to evaluate the actual organic loading rate. The actual F/M ratio was expected to be much higher than the apparent F/M ratio in MBR-SD. The kinetic parameters concerning the biodegradability of organics hardly affect the system performance. Instead, sludge solubilization ratio (alpha) in the SD process and particulate hydrolysis rate constant (k(h)) in biological reaction determine the sludge disintegration number (SDN), which is related with the overall economics of the MBR-SD system. Under reasonable alpha and k(h) values, SDN would range between 3 and 5 which means the amount of sludge required to be disintegrated would be 3-5 times higher for preventing a particular amount of sludge production. Finally, normalized sludge disintegration rate (q/V) which is needed to maintain a certain level of MLSS in the MBR-SD system was calculated as a function of F/V ratio. PMID:12697235

  18. Absolute density measurement of SD radicals in a supersonic jet at the quantum-noise-limit.

    PubMed

    Mizouri, Arin; Deng, L Z; Eardley, Jack S; Nahler, N Hendrik; Wrede, Eckart; Carty, David

    2013-12-01

    The absolute density of SD radicals in a supersonic jet has been measured down to (1.1 ± 0.1) × 10(5) cm(-3) in a modestly specified apparatus that uses a cross-correlated combination of cavity ring-down and laser-induced fluorescence detection. Such a density corresponds to 215 ± 21 molecules in the probe volume at any given time. The minimum detectable absorption coefficient was quantum-noise-limited and measured to be (7.9 ± 0.6) × 10(-11) cm(-1), in 200 s of acquisition time, corresponding to a noise-equivalent absorption sensitivity for the apparatus of (1.6 ± 0.1) × 10(-9) cm(-1) Hz(-1/2). PMID:24145480

  19. Microsporum fulvum IBRL SD3: as novel isolate for chicken feathers degradation.

    PubMed

    Darah, I; Nur-Diyana, A; Nurul-Husna, S; Jain, K; Lim, Sheh-Hong

    2013-12-01

    Keratinous wastes have increasingly become a problem and accumulate in the environment mainly in the form of feathers, generated mainly from a large number of poultry industries. As keratins are very difficult to degrade by general proteases, they pose a major environmental problem. Therefore, microorganisms which would effectively degrade keratins are needed for recycling such wastes. A geophilic dermatophyte, Microsporum fulvum IBRL SD3 which was isolated from a soil sample collected from a chicken feather dumping site using a baiting technique, was capable to produce keratinase significantly. The crude keratinase was able to degrade whole chicken feathers effectively. The end product of the degradation was protein that contained essential amino acids and may have potential application in animal feed production. Thus, M. fulvum could be a novel organism to produce keratinase for chicken feathers degradation. PMID:24013862

  20. Secondary metabolites from Penicillium pinophilum SD-272, a marine sediment-derived fungus.

    PubMed

    Wang, Ming-Hui; Li, Xiao-Ming; Li, Chun-Shun; Ji, Nai-Yun; Wang, Bin-Gui

    2013-06-01

    Two new secondary metabolites, namely, pinodiketopiperazine A (1) and 6,7-dihydroxy-3-methoxy-3-methylphthalide (2), along with alternariol 2,4-dimethyl ether (3) and L-5-oxoproline methyl ester (4), which were isolated from a natural source for the first time but have been previously synthesized, were characterized from the marine sediment-derived fungus Penicillium pinophilum SD-272. In addition, six known metabolites (5-10) were also identified. Their structures were elucidated by analysis of the NMR and mass spectroscopic data. The absolute configuration of compound 1 was determined by experimental and calculated ECD spectra. Compound 2 displayed potent brine shrimp (Artemia salina) lethality with LD₅₀ 11.2 μM. PMID:23792827

  1. Electrical Characterization of the RCA CDP1822SD Random Access Memory, Volume 1, Appendix a

    NASA Technical Reports Server (NTRS)

    Klute, A.

    1979-01-01

    Electrical characteristization tests were performed on 35 RCA CDP1822SD, 256-by-4-bit, CMOS, random access memories. The tests included three functional tests, AC and DC parametric tests, a series of schmoo plots, rise/fall time screening, and a data retention test. All tests were performed on an automated IC test system with temperatures controlled by a thermal airstream unit. All the functional tests, the data retention test, and the AC and DC parametric tests were performed at ambient temperatures of 25 C, -20 C, -55 C, 85 C, and 125 C. The schmoo plots were performed at ambient temperatures of 25 C, -55 C, and 125 C. The data retention test was performed at 25 C. Five devices failed one or more functional tests and four of these devices failed to meet the expected limits of a number of AC parametric tests. Some of the schmoo plots indicated a small degree of interaction between parameters.

  2. Isospin Symmetry Along The N=Z Line In The sd Shell

    SciTech Connect

    Della Vedova, F.; Lenzi, S. M.; Farnea, E.; Nespolo, M.; Bazzacco, D.; Brandolini, F.; Lunardi, S.; Menegazzo, R.; Rossi Alvarez, C.; Ur, C.A.; Ionescu-Bujor, M.; Bucurescu, D.; Iordachescu, A.; Marginean, N.; De Angelis, G.; Axiotis, M.; Napoli, D. R.; Bizzeti-Sona, A.; Bizzeti, P.G.

    2005-04-05

    Excited states have been studied in sd-shell nuclei following the 16O (70 MeV) + 24Mg (400 {mu}g/cm2) fusion-evaporation reaction. The GASP spectrometer in conjunction with the charged-particle detector ISIS and the Neutron ring allowed the detection of the {gamma}-rays in coincidence with evaporated light particles. New data on the mirror pairs A=31 and A=35 have been obtained. In particular, the comparison between the level schemes of 35Ar and 35Cl has confirmed the importance of the electromagnetic spin-orbit term, which explains the large Mirror Energy Difference values. Evidence of isospin mixing can be deduced from the E1 transitions.

  3. Support vector machine based IS/OS disruption detection from SD-OCT images

    NASA Astrophysics Data System (ADS)

    Wang, Liyun; Zhu, Weifang; Liao, Jianping; Xiang, Dehui; Jin, Chao; Chen, Haoyu; Chen, Xinjian

    2014-03-01

    In this paper, we sought to find a method to detect the Inner Segment /Outer Segment (IS/OS)disruption region automatically. A novel support vector machine (SVM) based method was proposed for IS/OS disruption detection. The method includes two parts: training and testing. During the training phase, 7 features from the region around the fovea are calculated. Support vector machine (SVM) is utilized as the classification method. In the testing phase, the training model derived is utilized to classify the disruption and non-disruption region of the IS/OS, and calculate the accuracy separately. The proposed method was tested on 9 patients' SD-OCT images using leave-one-out strategy. The preliminary results demonstrated the feasibility and efficiency of the proposed method.

  4. Source identification in acoustics and structural mechanics using Sierra/SD.

    SciTech Connect

    Walsh, Timothy Francis; Aquino, Wilkins; Ross, Michael

    2013-03-01

    In this report we derive both time and frequency-domain methods for inverse identification of sources in elastodynamics and acoustics. The inverse/design problem is cast in a PDE-constrained optimization framework with efficient computation of gradients using the adjoint method. The implementation of source inversion in Sierra/SD is described, and results from both time and frequency domain source inversion are compared to actual experimental data for a weapon store used in captive carry on a military aircraft. The inverse methodology is advantageous in that it provides a method for creating ground based acoustic and vibration tests that can reduce the actual number of flight tests, and thus, saving costs and time for the program.

  5. Toxicity of Methylcyclohexane and Its Effect on the Reproductive System in SD Rats

    PubMed Central

    Kang, Min-Gu; Kim, Tae-Gyun; Kang, Chung-Won

    2011-01-01

    Objectives There is limited data regarding the toxicity of methylcyclohexane, despite its wide use in rubber adhesives, paint diluents, and cleansing agents. This study aimed to verify the toxicity and influence on the reproductive system of methylcyclohexane after its repeated injection in Sprague Dawley (SD) rats. Methods Methylcyclohexane was injected subcutaneously into male and female SD rats once a day, five times a week, for 13 weeks at different doses (0, 10, 100, and 1,000 mg/kg/day) for each group. The toxicity of testing material was verified by observing the change in body and organ weight, hematological change, pathological findings, and effect on the reproductive system at each different concentration. Results In the 1,000 mg/kg/day group, there were cases of animal deaths. In animals that survived, hematological changes, including a decrease in the red blood cell count, were observed. A considerable weight gain or loss and pathological abnormalities in the liver, kidney, and other organs were found. However, the 10 and 100 mg/kg/day groups did not cause deaths or other specific abnormalities. In terms of reproductive toxicity, there were changes in hormone levels, including a significant decrease in hormones such as estradiol and progesterone (p < 0.001) in male animals. Menstrual cycle change for female animals did not show concentration dependency. Conclusion When injected repeatedly for 13 weeks, methylcyclohexane proved to be toxic for the liver, heart, and kidney at a high dose. The absolute toxic dose was 1,000 mg/kg/day, while the no observed adverse effect level was less than 100 mg/kg/day. The substance exerted little influence on the reproductive system. PMID:22953213

  6. SAMI3/SD-WACCM-X simulations of ionospheric variability during northern winter 2009

    NASA Astrophysics Data System (ADS)

    McDonald, S. E.; Sassi, F.; Mannucci, A. J.

    2015-09-01

    We have performed simulations using the Naval Research Laboratory's physics-based model of the ionosphere, Sami3 is A Model of the Ionosphere (SAMI3), to illustrate how neutral wind dynamics is responsible for day-to-day variability of the ionosphere. We have used neutral winds specified from the extended version of the specified dynamics Whole Atmosphere Community Climate Model (SD-WACCM-X), in which meteorology below 92 km is constrained by atmospheric specifications from an operational weather forecast model and reanalysis. To assess the realism of the simulations against observations, we have carried out a case study during January-February 2009, a dynamically disturbed time characterized by a sudden stratospheric warming (SSW) commencing 24 January 2009. Model results are compared with total electron content (TEC) from Jet Propulsion Laboratory global ionospheric maps. We show that SAMI3/SD-WACCM-X captures longitudinal variability in the equatorial ionization anomaly associated with nonmigrating tides, with strongest contributions coming from the diurnal eastward wave number 2 (DE2) and DE3. Both migrating and nonmigrating tides contribute to significant day-to-day variability, with TEC varying up to 16%. Our simulation during the SSW period reveals that at the Jicamarca longitude (285°E) on 27 January 2009 nonmigrating tides contribute to an enhancement of the electron density in the morning followed by a decrease in the afternoon. An enhancement of the semidiurnal eastward wave number 2 (SE2) and SE3 nonmigrating tides, likely associated with the appearance of the SSW, suggests that these tides increase the longitudinal variability of the SSW impact on the ionosphere. The conclusion is that realistic meteorology propagating upward from the lower atmosphere influences the dynamo region and reproduces aspects of the observed variability in the ionosphere.

  7. The study of the Oxytropis kansuensis-induced apoptotic pathway in the cerebrum of SD rats

    PubMed Central

    2013-01-01

    Background Locoweeds cause significant livestock poisoning and economic loss all over the world. Animals can develop locoism, a chronic neurological disease, after grazing on locoweeds. Oxytropis kansuensis is a variety of locoweed that contains swainsonine as its main toxic ingredient. The purpose of this study was to investigate the apoptotic pathway induced in the cerebrum by swainsonine. Results Twenty-four Sprague-Dawley rats were randomly divided into four groups (experimental groups I, II, III and a control group) and 6 SD rats of each group were feed in 3 cages separately. Rats were penned as groups and fed with feeds containing 15% (SW content 0.03‰), 30% (SW content 0.06‰), or 45% (SW content 0.09‰) O. kansuensis for experimental groups I, II, and III, respectively, or complete feed in the case of the control group. One hundred and nineteen days after poisoning, and all rats showed neurological disorders at different degrees, which were considered to be successful established a chronic poisoning model of O. kansuensis. rats were sacrificed and the expression of Fas, FasL, Bcl-2, Bax as well as cleaved caspase-3, -8 and -9 proteins in brain tissues were detected by Western blot. The results showed that SW treatment up-regulated Fas and Fas ligand (FasL) (P < 0.05), and that there was an increase in Bax and a decrease in Bcl-2 protein (P < 0.01). Moreover, SW treatment significantly increases the activation of caspase-3, 8 and -9, the key effectors in apoptosis pathway (P < 0.01). Conclusion Our data suggest that SW induces apoptosis in cells of the brain through death receptor and mitochondria-mediated, caspase-dependent apoptotic pathways in the brain tissue of SD rats. PMID:24148892

  8. Lactogenic Activity of an Enzymatic Hydrolysate from Octopus vulgaris and Carica papaya in SD Rats.

    PubMed

    Cai, Bingna; Chen, Hua; Sun, Han; Sun, Huili; Wan, Peng; Chen, Deke; Pan, Jianyu

    2015-11-01

    The traditional Chinese medicine theory believes that octopus papaya soup can stimulate milk production in lactating women. The objective of this study was to determine whether dietary supplementation with an enzymatic hydrolysate of Octopus vulgaris and Carica papaya (EHOC) could increase milk production and nutritional indexes in Sprague Dawley (SD) rats. Female SD rats (n = 24) were fed a control diet (n = 8), EHOC-supplemented diet, or a positive control diet (Shengruzhi) from day 10 of pregnancy to day 10 of lactation. Maternal serum, mammary gland (day 10 of lactation), milk, and pup weight (daily) were collected for analysis. Results showed that the EHOC diet obviously elevated daily milk yield and pup weight compared to the control group (P < .05). The EHOC diet was found to increase the concentration of prolactin (PRL), progesterone (P), estradiol (E2), and growth hormone (GH) significantly in the circulation and mammary gland. Mammary glands of EHOC-treated dams showed clear lobuloalveolar development and proliferation of myoepithelial cells, but no striking variations were observed among the groups. Furthermore, the nutrition content and immune globulin concentration in the milk of EHOC-supplemented dams were higher than those of the control group, especially the cholesterol, glucose, and IgG were higher by 44.98% (P < .001), 42.76% (P < .01), and 42.23% (P < .01), respectively. In conclusion, this article demonstrates that EHOC administration has beneficial effects on milk production in the dams and on performance of the dam and pup. These results indicate that EHOC could be explored as a potentially lactogenic nutriment for lactating women. PMID:26270883

  9. Local Variability of Macular Thickness Measurements With SD-OCT and Influencing Factors

    PubMed Central

    Miraftabi, Arezoo; Amini, Navid; Gornbein, Jeff; Henry, Sharon; Romero, Pablo; Coleman, Anne L.; Caprioli, Joseph; Nouri-Mahdavi, Kouros

    2016-01-01

    Purpose To compare the intrasession variability of spectral-domain optical coherence tomography (SD-OCT)-derived local macular thickness measures and explore influencing factors. Methods One hundred two glaucomatous eyes (102 patients) and 21 healthy eyes (21 subjects) with three good quality macular images during the same session were enrolled. Thickness measurements were calculated for 3° superpixels for the inner plexiform (IPL), ganglion cell (GCL), or retinal nerve fiber layers (mRNFL), GC/IPL, ganglion cell complex, and full macular thickness. Spatial distribution and magnitude of measurement errors (ME; differences between the 3 individual superpixel values and their mean) and association between MEs and thickness, age, axial length, and image quality were explored. Results MEs had a normal distribution with mostly random noise along with a small fraction of outliers (1.2%–6.6%; highest variability in mRNFL and on the nasal border) based on M-estimation. Boundaries of 95% prediction intervals for variability reached a maximum of 3 μm for all layers and diagnostic groups after exclusion of outliers. Correlation between proportion of outliers and thickness measures varied among various parameters. Age, axial length, or image quality did not influence MEs (P > 0.05 for both groups). Conclusions Local variability of macular SD-OCT measurements is low and uniform across the macula. The relationship between superpixel thickness and outlier proportion varied as a function of the parameter of interest. Translational Relevance Given the low and uniform variability within and across eyes, definition of an individualized ‘variability space' seems unnecessary. The variability measurements from this study could be used for designing algorithms for detection of glaucoma progression. PMID:27486555

  10. Evaluation of SD-208, a TGF-β-RI Kinase Inhibitor, as an Anticancer Agent in Retinoblastoma.

    PubMed

    Fadakar, Puran; Akbari, Abolfazl; Ghassemi, Fariba; Mobini, Gholam Reza; Mohebi, Masoumeh; Bolhassani, Manzar; Abed Khojasteh, Hoda; Heidari, Mansour

    2016-06-01

    Retinoblastoma is the most common intraocular tumor in children resulting from genetic alterations and transformation of mature retinal cells. The objective of this study was to investigate the effects of SD-208, TGF-β-RI kinase inhibitor, on the expression of some miRNAs including a miR-17/92 cluster in retinoblastoma cells. Prior to initiate this work, the cell proliferation was studied by Methyl Thiazolyl Tetrazolium (MTT) and bromo-2'-deoxyuridine (BrdU) assays. Then, the expression patterns of four miRNAs (18a, 20a, 22, and 34a) were investigated in the treated SD-208 (0.0, 1, 2 and 3 µM) and untreated Y-79 cells. A remarkable inhibition of the cell proliferation was found in Y-79 cells treated with SD-208 versus untreated cells. Also, the expression changes were observed in miRNAs 18a, 20a, 22 and 34a in response to SD-208 treatment (P<0.05). The findings of the present study suggest that the anti-cancer effect of SD-208 may be exerted due to the regulation of specific miRNAs, at least in this particular retinoblastoma cell line. To the best of the researchers' knowledge, this is the first report demonstrating that the SD-208 could alter the expression of tumor suppressive miRNAs as well as oncomiRs in vitro. In conclusion, the present data suggest that SD-208 could be an alternative agent in retinoblastoma treatment. PMID:27306340

  11. Refractive Error and Ocular Parameters: Comparison of Two SD-OCT Systems

    PubMed Central

    Ostrin, Lisa A.; Yuzuriha, Jill; Wildsoet, Christine F.

    2015-01-01

    Purpose Spectral domain optical coherence tomography (SD-OCT) was used to examine the influence of refractive error (RE) on foveal retinal and choroidal thicknesses and scleral canal width (SCW). The performance of the Cirrus and Bioptigen SD-OCT instruments was compared in the same eyes. Methods Both eyes of forty healthy human subjects, ages 22 to 38 years, were dilated and imaged, with the Cirrus OCT, using 6 mm 5-line rasters collapsed into one line, one centered on the fovea and one bisecting the optic nerve head. Seventy-two of the same eyes were imaged with the Bioptigen OCT, using 6 mm × 6 mm scans, one centered on the fovea and one on the optic nerve head. Subfoveal retinal and choroidal thicknesses and SCW were measured. Axial lengths (AL) and REs were obtained using an IOLMaster and a Grand Seiko autorefractor, respectively. Results Only right eyes were included in analyses. Spherical equivalent REs ranged from −12.18 to +8.12 D (mean: −3.44 ± 4.06 D), and ALs ranged from 20.56 to 29.17 mm (mean: 24.86 ± 1.91 mm). Myopia was associated with relatively thin choroids at the fovea (p<0.05) but normal retinal thickness. SCW was significantly correlated with AL as measured with the Bioptigen OCT (p<0.05). Retinal and choroidal thicknesses recorded with the Bioptigen OCT tended to be smaller than values obtained with the Cirrus OCT (mean difference: 5.63 and 24.76 µm, respectively), while the converse was true for the SCW (mean difference: 25.45 µm). Conclusions The finding that high myopes tend to have a thinner subfoveal choroid is consistent with previous studies. That high myopia was linked to enlarged scleral canals may help to explain the increased risk of glaucoma in myopia. Observed differences obtained with the Cirrus and Bioptigen instruments urge caution in comparing results collected with different instruments. PMID:25785537

  12. Intravenous Toxicity Study of Water-soluble Ginseng Pharmacopuncture in SD Rats

    PubMed Central

    Yu, Jun-Sang; Sun, Seung-Ho; Lee, Kwang-Ho; Kwon, Ki-Rok

    2015-01-01

    Objectives: Radix Ginseng has been used for thousands of years to treat a wide variety of diseases. Radix ginseng has also been used as a traditional medicine for boosting Qi energy and tonifying the spleen and lungs. Traditionally, its effect could be obtained orally. Nowadays, a new method, the injection of herbal medicine, is being used. This study was performed to investigate the single-dose intravenous toxicity of water-soluble ginseng pharmacopuncture (WSGP) in Sprague-Dawley (SD) rats. Methods: All experiments were carried out at Biotoxtech, an institute authorized to perform non-clinical studies under the regulation of Good Laboratory Practice (GLP). At the age of six weeks, 40 SD rats, 20 male rats and 20 female rats, were allocated into one of 4 groups according to the dosages they would receive. The WSGP was prepared in the Korean Pharmacopuncture Institute under the regulation of Korea-Good Manufacturing Practice (K-GMP). Dosages of WSGP were 0.1, 0.5 and 1.0 mL/animal for the experimental groups, and normal saline was administered to the control group. The rat's general conditions and body weights, the results of their hematological and biochemistry tests, and their necropsy and histopathological findings were investigated to identify the toxicological effect of WSGP injected intravenously. The effect was examined for 14 days after the WSGP injection. This study was performed under the approval of the Institutional Animal Ethics Committee of Biotoxtech. Results: No deaths were found in this single-dose toxicity test on the intravenous injection of WSGP, and no significant changes in the rat's general conditions and body weights, the results on their hematological and biochemistry test, and their necropsy findings were observed during the test. The local area of the injection site showed minial change. The lethal dose was assumed to be over 1.0 mL/animal in both sexes. Conclusion: These results indicate that WSGP is safe at dosages up to 1 m

  13. Diversity of DIS, SD and psi hairpins in HIV-1 isolates of group M: in silico study.

    PubMed

    Zarudnaya, M I; Potyahaylo, A L; Kolomiets, I N; Hovorun, D M

    2007-01-01

    The primary sequence and secondary structure of the region encompassing DIS, SD and psi hairpins in HIV-1 genomic RNAs have been analyzed for 731 group M isolates from NCBI database. The secondary structures have been predicted by the m fold program (M. Zuker). Though the primary sequence of the region studied was found to be highly heterogeneous, this region is folded into DIS, SD and psi hairpins (DIS-, SD- and psi-like hairpins) in 96% of the isolates studied. The phylogenetic analysis showed that the most frequent variants of DIS hairpin (DIS(Lai), DIS(Mal) and DIS(C)) tolerate certain base changes. Particularly, base changes at stem position 23 occur 5 and 33 times more frequently in DIS(Lai) than in DIS(Mal) and DIS(C), respectively, while A insertion at the 5'end of apical loop is tolerated in DIS(Mal) and DIS(C) but not in DIS(Lai). We have revealed that the bottom base pair substitution G-C --> A-U in SD hairpin is highly specific for subtype D isolates. All variants of DIS, SD and psi hairpins found in our database are discussed, systematized and presented in schemes of hypothetical transitions between variants via a single base change. Most variants of DIS and psi hairpins were found to adopt several conformations. PMID:18030736

  14. Radon as a tool to monitor transient permeability changes: on-line measurements in a tri-axial cell

    NASA Astrophysics Data System (ADS)

    Girault, Frédéric; Schubnel, Alexandre; Pili, Éric

    2014-05-01

    Radon-222 is a radioactive gas of half-life of 3.8 days which is naturally produced in the Earth's crust. This informs generally about the transfers in the subsurface and is considered as a potential earthquake precursor. In this study, deformation experiments are performed in the laboratory on various granites, for which the radon source term is known (effective radium concentration). Radon concentration is continuously measured on-line under isotropic stress and deformation using a tri-axial cell, together with acoustic emissions, seismic velocity, deformation rates and geometry. Pore fluid pressure is fixed and maintains a flush of inert gas through the sample, which allows radon to be expelled from the porous network of the sample. This also leads to permeability determinations. Radon release shows a large sensitivity to various intrinsic and external parameters. While radon release is stable under constant isotropic conditions, it increases with confining pressure, because radon is more concentrated as the permeability decreases. However, above a given confining pressure threshold, radon release decreases while permeability continues to decrease, mainly due to the closure of cracks. Therefore, any change of permeability in the sample, even relatively small, is marked by a consecutive change of the radon release. At the macroscopic rupture of the sample, significant transient radon release is observed simultaneously to the rupture, or some time after. This transient radon peak results from isolated microporosity being newly connected to the permeable network rather than new crack surface creation per se. This hypothesis is sometimes proposed to account for radon anomalies observed before and after large earthquakes. As our transient radon signals are observed just after or near the time the rupture occurs, we might tentatively raise questions concerning some precursory observations. All these effects are now being quantified. This study and the developed

  15. Validity of using tri-axial accelerometers to measure human movement - Part I: Posture and movement detection.

    PubMed

    Lugade, Vipul; Fortune, Emma; Morrow, Melissa; Kaufman, Kenton

    2014-02-01

    A robust method for identifying movement in the free-living environment is needed to objectively measure physical activity. The purpose of this study was to validate the identification of postural orientation and movement from acceleration data against visual inspection from video recordings. Using tri-axial accelerometers placed on the waist and thigh, static orientations of standing, sitting, and lying down, as well as dynamic movements of walking, jogging and transitions between postures were identified. Additionally, subjects walked and jogged at self-selected slow, comfortable, and fast speeds. Identification of tasks was performed using a combination of the signal magnitude area, continuous wavelet transforms and accelerometer orientations. Twelve healthy adults were studied in the laboratory, with two investigators identifying tasks during each second of video observation. The intraclass correlation coefficients for inter-rater reliability were greater than 0.95 for all activities except for transitions. Results demonstrated high validity, with sensitivity and positive predictive values of greater than 85% for sitting and lying, with walking and jogging identified at greater than 90%. The greatest disagreement in identification accuracy between the algorithm and video occurred when subjects were asked to fidget while standing or sitting. During variable speed tasks, gait was correctly identified for speeds between 0.1m/s and 4.8m/s. This study included a range of walking speeds and natural movements such as fidgeting during static postures, demonstrating that accelerometer data can be used to identify orientation and movement among the general population. PMID:23899533

  16. Development of a Subcell Based Modeling Approach for Modeling the Architecturally Dependent Impact Response of Triaxially Braided Polymer Matrix Composites

    NASA Technical Reports Server (NTRS)

    Sorini, Chris; Chattopadhyay, Aditi; Goldberg, Robert K.; Kohlman, Lee W.

    2016-01-01

    Understanding the high velocity impact response of polymer matrix composites with complex architectures is critical to many aerospace applications, including engine fan blade containment systems where the structure must be able to completely contain fan blades in the event of a blade-out. Despite the benefits offered by these materials, the complex nature of textile composites presents a significant challenge for the prediction of deformation and damage under both quasi-static and impact loading conditions. The relatively large mesoscale repeating unit cell (in comparison to the size of structural components) causes the material to behave like a structure rather than a homogeneous material. Impact experiments conducted at NASA Glenn Research Center have shown the damage patterns to be a function of the underlying material architecture. Traditional computational techniques that involve modeling these materials using smeared homogeneous, orthotropic material properties at the macroscale result in simulated damage patterns that are a function of the structural geometry, but not the material architecture. In order to preserve heterogeneity at the highest length scale in a robust yet computationally efficient manner, and capture the architecturally dependent damage patterns, a previously-developed subcell modeling approach where the braided composite unit cell is approximated as a series of four adjacent laminated composites is utilized. This work discusses the implementation of the subcell methodology into the commercial transient dynamic finite element code LS-DYNA (Livermore Software Technology Corp.). Verification and validation studies are also presented, including simulation of the tensile response of straight-sided and notched quasi-static coupons composed of a T700/PR520 triaxially braided [0deg/60deg/-60deg] composite. Based on the results of the verification and validation studies, advantages and limitations of the methodology as well as plans for future work

  17. Phase-space transport in cuspy triaxial potentials: can they be used to construct self-consistent equilibria?

    NASA Astrophysics Data System (ADS)

    Siopis, Christos; Kandrup, Henry E.

    2000-11-01

    This paper focuses on the statistical properties of chaotic orbit ensembles evolved in triaxial generalizations of the Dehnen potential which have been proposed recently to model realistic ellipticals that have a strong density cusp and manifest significant deviations from axisymmetry. Allowance is made for a possible supermassive black hole, as well as low-amplitude friction, noise, and periodic driving which can mimic irregularities associated with discreteness effects and/or an external environment. The chaos exhibited by these potentials is quantified by determining (1) how the relative number of chaotic orbits depends on the steepness of the cusp, as probed by γ, the power-law exponent with which density diverges, and MBH, the black hole mass, (2) how the size of the largest Lyapunov exponent varies with γ and MBH, and (3) the extent to which Arnold webs significantly impede phase-space transport, both with and without perturbations. The most important conclusions dynamically are (1) that, in the absence of irregularities, chaotic orbits tend to be extremely `sticky', so that different pieces of the same chaotic orbit can behave very differently for times ~10000tD or more, but (2) that even very low-amplitude perturbations can prove efficient in erasing many - albeit not all - of these differences. The implications of these facts are discussed both for the structure and evolution of real galaxies and for the possibility of constructing approximate near-equilibrium models using Schwarzschild's method. For example, when trying to use Schwarzschild's method to construct model galaxies containing significant numbers of chaotic orbits, it seems advantageous to build libraries with chaotic orbits evolved in the presence of low-amplitude friction and noise, since such noisy orbits are more likely to represent reasonable approximations to time-independent building blocks. Much of the observed qualitative behaviour can be reproduced with a toy potential given as the

  18. Travel Times of Later Phases for Transmitting Waves through a Fracturing Westerly Granite Sample under a Triaxial Compressive Condition

    NASA Astrophysics Data System (ADS)

    Imahori, A.; Kawakata, H.; Hirano, S.; Yoshimitsu, N.; Takahashi, N.

    2015-12-01

    In laboratory, it is well-known that the elastic wave speed varies prior to compression fracture of the rock (e.g., Lockner et al., 1977, JGR). Using an enough number of travel times of elastic wave paths in a sample, we can estimate internal structure of the sample. However, the number of the elastic wave transducers is limited, and only the travel times of the first arrival are available in most experiments. Employing broadband transducers (Yoshimitsu et al., 2014, GRL), later phases become available to be analyzed. In the present study, we conduct a triaxial compressive test at room temperature under a dry condition and a confining pressure of 50 MPa, using a cylindrical Westerly granite sample of 100 mm long by 50 mm in diameter. Eight transducers are attached on the sample surface. One of the transducers is used as a wave source and voltage steps are repeatedly applied to it. The elastic waves passing through the sample are sensed by the other broadband transducers, and recorded at a sampling rate of 20 Msps. P-wave speed is estimated from the travel time of the direct P, and Vp/Vs value is assumed to be the √3 to give S-wave speed. We assume that all wave paths never bend except at the top and bottom surface of the sample. We calculate the travel times of later phases reflected at the top and/or bottom surfaces within 3 times. We collate the calculated travel times with observed waveforms. We can identify the travel time of two phases: single reflection from both top and bottom of the sample. On the other hand, some other observed and calculated phase arrivals do not match with each other. Then, we try to identify some remarkable phases using the calculated travel times of PS and SP converted waves and interfacial waves, taking into consideration of wave speed anisotropy.

  19. Multiple Sclerosis

    MedlinePlus

    Multiple sclerosis (MS) is a nervous system disease that affects your brain and spinal cord. It damages the ... attacks healthy cells in your body by mistake. Multiple sclerosis affects women more than men. It often begins ...

  20. Multiple Pregnancy

    MedlinePlus

    ... is called multiple pregnancy . If more than one egg is released during the menstrual cycle and each ... fraternal twins (or more). When a single fertilized egg splits, it results in multiple identical embryos. This ...

  1. Multiple myeloma

    MedlinePlus

    Plasma cell dyscrasia; Plasma cell myeloma; Malignant plasmacytoma; Plasmacytoma of bone; Myeloma - multiple ... Multiple myeloma most commonly causes: Low red blood cell count ( anemia ), which can lead to fatigue and ...

  2. The estrogenic effects of benzylparaben at low doses based on uterotrophic assay in immature SD rats.

    PubMed

    Hu, Ying; Zhang, Zhaobin; Sun, Libei; Zhu, Desheng; Liu, Qingchun; Jiao, Jian; Li, Jun; Qi, Mingwen

    2013-03-01

    Benzylparaben (BzP), a type of parabens being used as a preservative agent in cosmetics, food, and pharmaceutical products, may be ingested by humans. In this study, we performed an immature uterotrophic assay using Sprague Dawley (SD) rats by intragastric administration to determine the estrogenic effects of BzP and found significant increases in uterine weight with doses of 0.16 mg/kg body weight and higher (P<0.05). The in vivo estrogenicity of BzP was supported by in vitro results from the human estrogen receptor α (hERα)-coactivator recruiting assay and in silico molecular docking analysis performed in this study. The in vitro estrogenic activity of BzP can be observed at concentrations of 1.0×10(-8) M and higher. Molecular docking analysis showed that BzP fits well into the agonist pocket of hERα. The lowest observed effect dose (LOED) (0.16 mg/kg/day) of BzP is much lower than the documented LOEDs of other parabens. Actual risk may exist for people who consume a diet high in BzP or use BzP-laden cosmetics. In addition, we tested the sensitivity of Wistar rats to 17β-estradiol by immature uterotrophic assay, and no obvious uterotrophic response was observed in the rats given doses up to 100 μg/kg body weight. PMID:23220609

  3. Spectrum of {gamma} rays from the decay of SD to normal states in {sup 191}Hg

    SciTech Connect

    Gassmann, D.; Khoo, T.L.; Lauritsen, T.

    1995-08-01

    In B.a.7. we propose that the statistical spectrum emitted from a sharp single excited state serves as a probe of pairing in excited states. A specific test of this proposal is the comparison of the spectra from even-even and odd-even nuclei. Whereas a pair gap exists in an even-even nucleus, it gets filled in an odd-even nucleus. Consequently, low-energy transitions can arise in the latter case, whereas they are calculated to be absent in the former case because very few levels exist in the cold gap region. In addition, transitions between 1.4 - 2.2 MeV, which {open_quotes}jump{close_quotes} across the gap, are predicted to have lower yield in the odd-even nuclei. Serendipitously, decay from a superdeformed state serves as a good initial excited sharp state. We extracted the spectrum pairwise-coincident with SD lines in {sup 191}Hg from Gammasphere data and compared it with the equivalent spectra from the even-even nuclei {sup 192,194}Hg. The differences that are predicted to occur are indeed observed. Thus, the data support our proposal that the reduction of pairing with thermal excitation energy can be probed with statistical decay spectra.

  4. Neutron Skins and Halo Orbits in the sd and pf Shells.

    PubMed

    Bonnard, J; Lenzi, S M; Zuker, A P

    2016-05-27

    The strong dependence of Coulomb energies on nuclear radii makes it possible to extract the latter from calculations of the former. The resulting estimates of neutron skins indicate that two mechanisms are involved. The first one-isovector monopole polarizability-amounts to noting that when a particle is added to a system it drives the radii of neutrons and protons in different directions, tending to equalize the radii of both fluids independently of the neutron excess. This mechanism is well understood and the Duflo-Zuker (small) neutron skin values derived 14 years ago are consistent with recent measures and estimates. The alternative mechanism involves halo orbits whose huge sizes tend to make the neutron skins larger and have a subtle influence on the radial behavior of sd and pf shell nuclei. In particular, they account for the sudden rise in the isotope shifts of nuclei beyond N=28 and the near constancy of radii in the A=40-56 region. This mechanism, detected here for the first time, is not well understood and may well go beyond the Efimov physics usually associated with halo orbits. PMID:27284653

  5. A search for substellar objects orbiting the sdB eclipsing binary HS 0705+6700

    NASA Astrophysics Data System (ADS)

    Qian, S.-B.; Shi, G.; Zola, S.; Koziel-Wierzbowska, D.; Winiarski, M.; Szymanski, T.; Ogloza, W.; Li, L.-J.; Zhu, L.-Y.; Liu, L.; He, J.-J.; Liao, W.-P.; Zhao, E.-G.; Wang, J.-J.; Zhang, J.; Jiang, L.-Q.

    2013-12-01

    By using 78 newly determined timings of light minima together with those collected from the literature, we analysed the changes in the observed minus calculated (O-C) diagram in HS 0705+6700, a short-period (2.3 h) eclipsing binary that consists of a very hot subdwarf B-type (sdB) star and a very cool fully convective red dwarf. We confirmed the cyclic variation in the O-C and refined the parameters of the circumbinary brown dwarf (reported to orbit the binary system in 2009) by analysing the changes for the light travel time effect that arises from the gravitational influence of the third body. Our results indicate the lower mass limit of the third body to be M3 sin i' = 33.7(±1.6) MJup. This companion would be a brown dwarf if its orbital inclination is larger than 27.7° and it is orbiting the central eclipsing binary with an eccentricity e ˜ 0.2 at a separation of about 3.7(±0.1) au.

  6. Classification of SD-OCT Volumes Using Local Binary Patterns: Experimental Validation for DME Detection

    PubMed Central

    Cheung, Carol Y.; Wong, Tien Y.; Lamoureux, Ecosse; Milea, Dan; Mériaudeau, Fabrice; Sidibé, Désiré

    2016-01-01

    This paper addresses the problem of automatic classification of Spectral Domain OCT (SD-OCT) data for automatic identification of patients with DME versus normal subjects. Optical Coherence Tomography (OCT) has been a valuable diagnostic tool for DME, which is among the most common causes of irreversible vision loss in individuals with diabetes. Here, a classification framework with five distinctive steps is proposed and we present an extensive study of each step. Our method considers combination of various preprocessing steps in conjunction with Local Binary Patterns (LBP) features and different mapping strategies. Using linear and nonlinear classifiers, we tested the developed framework on a balanced cohort of 32 patients. Experimental results show that the proposed method outperforms the previous studies by achieving a Sensitivity (SE) and a Specificity (SP) of 81.2% and 93.7%, respectively. Our study concludes that the 3D features and high-level representation of 2D features using patches achieve the best results. However, the effects of preprocessing are inconsistent with different classifiers and feature configurations. PMID:27555965

  7. Effect and mechanism of Salicornia bigelovii Torr. plant salt on blood pressure in SD rats.

    PubMed

    Zhang, Shumeng; Wei, Mingqian; Cao, Chunjie; Ju, Yaoyao; Deng, Yanqun; Ye, Tianwen; Xia, Zufeng; Chen, Meizhen

    2015-03-01

    In this paper, the effect and mechanism of Salicornia bigelovii Torr. plant salt (SPS) on blood pressure in Sprague Dawley (SD) rats were investigated. The results showed that the edible salt induced hypertension, but the SPS did not. Organ indices and Hematoxylin-Eosin (HE) staining analysis indicated that SPS had a protective effect on the kidney and liver. In comparison with the edible salt-treated group, nitric oxide (NO) content, angiotensin-II (Ang-II) and endothelin-1 (ET-1) levels in the serum of the SPS-treated group had no obvious changes, but serum creatinine concentration significantly decreased. Moreover, superoxide dismutase (SOD) and Na(+)-K(+)-ATPase activity increased while malondialdehyde (MDA) content decreased in the SPS-treated group. In conclusion, a long-term high salt intake could lead to hypertension. SPS, as a salt substitute, could increase the body's antioxidant ability to protect the kidney and liver from the damage caused by a high salt intake and effectively avoid the occurrence of hypertension. PMID:25631641

  8. Risk and Vulnerability Analysis of Satellites Due to MM/SD with PIRAT

    NASA Astrophysics Data System (ADS)

    Kempf, Scott; Schafer, Frank Rudolph, Martin; Welty, Nathan; Donath, Therese; Destefanis, Roberto; Grassi, Lilith; Janovsky, Rolf; Evans, Leanne; Winterboer, Arne

    2013-08-01

    Until recently, the state-of-the-art assessment of the threat posed to spacecraft by micrometeoroids and space debris was limited to the application of ballistic limit equations to the outer hull of a spacecraft. The probability of no penetration (PNP) is acceptable for assessing the risk and vulnerability of manned space mission, however, for unmanned missions, whereby penetrations of the spacecraft exterior do not necessarily constitute satellite or mission failure, these values are overly conservative. The newly developed software tool PIRAT (Particle Impact Risk and Vulnerability Analysis Tool) has been developed based on the Schäfer-Ryan-Lambert (SRL) triple-wall ballistic limit equation (BLE), applicable for various satellite components. As a result, it has become possible to assess the individual failure rates of satellite components. This paper demonstrates the modeling of an example satellite, the performance of a PIRAT analysis and the potential for subsequent design optimizations with respect of micrometeoroid and space debris (MM/SD) impact risk.

  9. Immunologic effects of anti-D (WinRho-SD) in children with immune thrombocytopenic purpura.

    PubMed

    Zimmerman, S A; Malinoski, F J; Ware, R E

    1998-02-01

    Intravenous immunoglobulin (IVIG) is an effective treatment for immune thrombocytopenic purpura (ITP) that induces transient blockade of the reticuloendothelial system (RES) with additional effects including alteration of T lymphocyte subsets and suppression of in vitro T lymphocyte proliferation. As anti-D also is an effective treatment for ITP, we investigated its in vitro and in vivo immunologic effects. The in vitro effects of various agents used in ITP therapy were compared using T lymphocyte proliferation assays. Anti-D caused significantly less inhibition than IVIG or dexamethasone, but non-specific protein was as suppressive as IVIG. Six children with chronic ITP were studied following anti-D administration. Patients received a single dose of anti-D (WinRho-SD, 50 microg/kg i.v. over 5 min) and were studied on day 0, day 7, and 1 month later. Anti-D did not affect T lymphocyte subsets including the T cell receptor variable beta repertoire, in vitro T lymphocyte proliferation to mitogens, recall antigens, or interleukin-2, in vitro IgG synthesis induced by pokeweed mitogen, or T lymphocyte cytokine mRNA levels. We conclude that anti-D has no demonstrable in vitro or in vivo effects on lymphocyte enumeration or function, and therefore likely is effective in the treatment of ITP primarily through RES blockade. PMID:9462545

  10. Optimization of a bioactive exopolysaccharide production from endophytic Fusarium solani SD5.

    PubMed

    Mahapatra, Subhadip; Banerjee, Debdulal

    2013-09-12

    Endophytic fungi were less investigated for exopolysaccharide production. In this study endophytic Fusarium solani SD5 was used for optimization of exopolysaccharide production. One variable at a time method and response surface methodology were employed to explore the optimum medium compositions and fermentation conditions. The organism produced maximum exopolysaccharide after 13.68 days of incubation at 28 °C in potato dextrose broth supplemented with (g%/l) glucose, 9.8; yeast extract, 0.69; KCl, 0.05; KH₂PO₄, 0.05 with medium pH 6.46. Use of 50 ml medium in 250 ml Erlenmeyer flask gives highest exopolysaccharide production. The organism produced more than two times higher exopolysaccharide (2.276 ± 0.032 g/l EPS) at optimized condition compared to pre-optimized condition (0.96 ± 0.021). In vivo toxicity test established nontoxic nature of the EPS (≤400 mg EPS/Kg of body weight). The EPS slightly altered intestinal indigenous bacteria and influenced the growth of beneficial Lactobacillus spp. PMID:23911494

  11. Alpha-cluster spectroscopy in 40Ca and in the sd-shell closure region

    NASA Astrophysics Data System (ADS)

    Reidemeister, G.; Ohkubo, S.; Michel, F.

    1990-01-01

    The low-energy 36(α,α) elastic scattering data of Gaul et al. are analyzed within the frame of the optical model, using energy-independent Woods-Saxon squared or model-independent geometries for the real part of the potential. The optical-model scattering amplitude is decomposed into its barrier and internal wave components to understand the rapid and complicated evolution of the angular distributions with incident energy. The properties of the low-energy bound and quasibound states supported by this potential are compared with those of the states of the deformed 4p-4h rotational band in 40Ca, built on the Jπ=0+, Ex=3.35 MeV state. The possibility of extending this local potential model approach to neighboring nuclei near the sd-shell closure is discussed. A negative-parity band of states with appreciable α-cluster character, starting around the α-particle threshold, is expected to be systematically present in this mass region.

  12. Alleviating anastrozole induced bone toxicity by selenium nanoparticles in SD rats.

    PubMed

    Vekariya, Kiritkumar K; Kaur, Jasmine; Tikoo, Kulbhushan

    2013-04-15

    Aromatase inhibitors like anastrozole play an undisputed key role in the treatment of breast cancer, but on the other hand, various side effects like osteoporosis and increased risk of bone fracture accompany the chronic administration of these drugs. Here we show for the first time that selenium nanoparticles, when given in conjugation to anastrozole, lower the bone toxicity caused by anastrozole and thus reduce the probable damage to the bone. Selenium nanoparticles at a dose of 5μg/ml significantly reduced the cell death caused by anastrozole (1μM) in HOS (human osteoblast) cells. In addition, our results also highlighted that in female SD rat model, SeNPs (0.25, 0.5, 1mg/kg/day) significantly prevented the decrease in bone density and increase in biochemical markers of bone resorption induced by anastrozole (0.2mg/kg/day) treatment. Histopathological examination of the femurs of SeNP treated group revealed ossification, mineralization, calcified cartilaginous deposits and a marginal osteoclastic activity, all of which indicate a marked restorative action, suggesting the protective action of the SeNPs. Interestingly, SeNPs (1mg/kg/day) also exhibited protective effect in ovariectomized rat model, by preventing osteoporosis, which signifies that bone loss due to estrogen deficiency can be effectively overcome by using SeNPs. PMID:23415680

  13. Classification of SD-OCT Volumes Using Local Binary Patterns: Experimental Validation for DME Detection.

    PubMed

    Lemaître, Guillaume; Rastgoo, Mojdeh; Massich, Joan; Cheung, Carol Y; Wong, Tien Y; Lamoureux, Ecosse; Milea, Dan; Mériaudeau, Fabrice; Sidibé, Désiré

    2016-01-01

    This paper addresses the problem of automatic classification of Spectral Domain OCT (SD-OCT) data for automatic identification of patients with DME versus normal subjects. Optical Coherence Tomography (OCT) has been a valuable diagnostic tool for DME, which is among the most common causes of irreversible vision loss in individuals with diabetes. Here, a classification framework with five distinctive steps is proposed and we present an extensive study of each step. Our method considers combination of various preprocessing steps in conjunction with Local Binary Patterns (LBP) features and different mapping strategies. Using linear and nonlinear classifiers, we tested the developed framework on a balanced cohort of 32 patients. Experimental results show that the proposed method outperforms the previous studies by achieving a Sensitivity (SE) and a Specificity (SP) of 81.2% and 93.7%, respectively. Our study concludes that the 3D features and high-level representation of 2D features using patches achieve the best results. However, the effects of preprocessing are inconsistent with different classifiers and feature configurations. PMID:27555965

  14. Finger Multiplication

    ERIC Educational Resources Information Center

    Simanihuruk, Mudin

    2011-01-01

    Multiplication facts are difficult to teach. Therefore many researchers have put a great deal of effort into finding multiplication strategies. Sherin and Fuson (2005) provided a good survey paper on the multiplication strategies research area. Kolpas (2002), Rendtorff (1908), Dabell (2001), Musser (1966) and Markarian (2009) proposed the finger…

  15. Multiple Sclerosis

    MedlinePlus

    ... Awards Enhancing Diversity Find People About NINDS NINDS Multiple Sclerosis Information Page Condensed from Multiple Sclerosis: Hope Through ... en Español Additional resources from MedlinePlus What is Multiple Sclerosis? An unpredictable disease of the central nervous system, ...

  16. Discovery, characterization and in vivo activity of pyocin SD2, a protein antibiotic from Pseudomonas aeruginosa

    PubMed Central

    McCaughey, Laura C.; Josts, Inokentijs; Grinter, Rhys; White, Paul; Byron, Olwyn; Tucker, Nicholas P.; Matthews, Jacqueline M.; Kleanthous, Colin; Whitchurch, Cynthia B.; Walker, Daniel

    2016-01-01

    Increasing rates of antibiotic resistance among Gram-negative pathogens such as Pseudomonas aeruginosa means alternative approaches to antibiotic development are urgently required. Pyocins, produced by P. aeruginosa for intraspecies competition, are highly potent protein antibiotics known to actively translocate across the outer membrane of P. aeruginosa. Understanding and exploiting the mechanisms by which pyocins target, penetrate and kill P. aeruginosa is a promising approach to antibiotic development. In this work we show the therapeutic potential of a newly identified tRNase pyocin, pyocin SD2, by demonstrating its activity in vivo in a murine model of P. aeruginosa lung infection. In addition, we propose a mechanism of cell targeting and translocation for pyocin SD2 across the P. aeruginosa outer membrane. Pyocin SD2 is concentrated at the cell surface, via binding to the common polysaccharide antigen (CPA) of P. aeruginosa lipopolysaccharide (LPS), from where it can efficiently locate its outer membrane receptor FpvAI. This strategy of utilizing both the CPA and a protein receptor for cell targeting is common among pyocins as we show that pyocins S2, S5 and SD3 also bind to the CPA. Additional data indicate a key role for an unstructured N-terminal region of pyocin SD2 in the subsequent translocation of the pyocin into the cell. These results greatly improve our understanding of how pyocins target and translocate across the outer membrane of P. aeruginosa. This knowledge could be useful for the development of novel anti-pseudomonal therapeutics and will also support the development of pyocin SD2 as a therapeutic in its own right. PMID:27252387

  17. Discovery, characterization and in vivo activity of pyocin SD2, a protein antibiotic from Pseudomonas aeruginosa.

    PubMed

    McCaughey, Laura C; Josts, Inokentijs; Grinter, Rhys; White, Paul; Byron, Olwyn; Tucker, Nicholas P; Matthews, Jacqueline M; Kleanthous, Colin; Whitchurch, Cynthia B; Walker, Daniel

    2016-08-01

    Increasing rates of antibiotic resistance among Gram-negative pathogens such as Pseudomonas aeruginosa means alternative approaches to antibiotic development are urgently required. Pyocins, produced by P. aeruginosa for intraspecies competition, are highly potent protein antibiotics known to actively translocate across the outer membrane of P. aeruginosa. Understanding and exploiting the mechanisms by which pyocins target, penetrate and kill P. aeruginosa is a promising approach to antibiotic development. In this work we show the therapeutic potential of a newly identified tRNase pyocin, pyocin SD2, by demonstrating its activity in vivo in a murine model of P. aeruginosa lung infection. In addition, we propose a mechanism of cell targeting and translocation for pyocin SD2 across the P. aeruginosa outer membrane. Pyocin SD2 is concentrated at the cell surface, via binding to the common polysaccharide antigen (CPA) of P. aeruginosa lipopolysaccharide (LPS), from where it can efficiently locate its outer membrane receptor FpvAI. This strategy of utilizing both the CPA and a protein receptor for cell targeting is common among pyocins as we show that pyocins S2, S5 and SD3 also bind to the CPA. Additional data indicate a key role for an unstructured N-terminal region of pyocin SD2 in the subsequent translocation of the pyocin into the cell. These results greatly improve our understanding of how pyocins target and translocate across the outer membrane of P. aeruginosa. This knowledge could be useful for the development of novel anti-pseudomonal therapeutics and will also support the development of pyocin SD2 as a therapeutic in its own right. PMID:27252387

  18. Aquaporin 4-specific T cells and NMO-IgG cause primary retinal damage in experimental NMO/SD.

    PubMed

    Zeka, Bleranda; Hastermann, Maria; Kaufmann, Nathalie; Schanda, Kathrin; Pende, Marko; Misu, Tatsuro; Rommer, Paulus; Fujihara, Kazuo; Nakashima, Ichiro; Dahle, Charlotte; Leutmezer, Fritz; Reindl, Markus; Lassmann, Hans; Bradl, Monika

    2016-01-01

    Neuromyelitis optica/spectrum disorder (NMO/SD) is a severe, inflammatory disease of the central nervous system (CNS). In the majority of patients, it is associated with the presence of pathogenic serum autoantibodies (the so-called NMO-IgGs) directed against the water channel aquaporin 4 (AQP4), and with the formation of large, astrocyte-destructive lesions in spinal cord and optic nerves. A large number of recent studies using optical coherence tomography (OCT) demonstrated that damage to optic nerves in NMO/SD is also associated with retinal injury, as evidenced by retinal nerve fiber layer (RNFL) thinning and microcystic inner nuclear layer abnormalities. These studies concluded that retinal injury in NMO/SD patients results from secondary neurodegeneration triggered by optic neuritis.However, the eye also contains cells expressing AQP4, i.e., Müller cells and astrocytes in the retina, epithelial cells of the ciliary body, and epithelial cells of the iris, which raised the question whether the eye can also be a primary target in NMO/SD. Here, we addressed this point in experimental NMO/SD (ENMO) induced in Lewis rat by transfer of AQP4268-285-specific T cells and NMO-IgG.We show that these animals show retinitis and subsequent dysfunction/damage of retinal axons and neurons, and that this pathology occurs independently of the action of NMO-IgG. We further show that in the retinae of ENMO animals Müller cell side branches lose AQP4 reactivity, while retinal astrocytes and Müller cell processes in the RNFL/ganglionic cell layers are spared. These changes only occur in the presence of both AQP4268-285-specific T cells and NMO-IgG.Cumulatively, our data show that damage to retinal cells can be a primary event in NMO/SD. PMID:27503347

  19. Multiplicity Counting

    SciTech Connect

    Geist, William H.

    2015-12-01

    This set of slides begins by giving background and a review of neutron counting; three attributes of a verification item are discussed: 240Pueff mass; α, the ratio of (α,n) neutrons to spontaneous fission neutrons; and leakage multiplication. It then takes up neutron detector systems – theory & concepts (coincidence counting, moderation, die-away time); detector systems – some important details (deadtime, corrections); introduction to multiplicity counting; multiplicity electronics and example distributions; singles, doubles, and triples from measured multiplicity distributions; and the point model: multiplicity mathematics.

  20. Primordial SdS universe from a 5D vacuum: scalar field fluctuations on Schwarzschild and Hubble horizons

    SciTech Connect

    Aguilar, José Edgar Madriz; Bellini, Mauricio E-mail: mbellini@mdp.edu.ar

    2010-11-01

    We study scalar field fluctuations of the inflaton field in an early inflationary universe on an effective 4D Schwarzschild-de Sitter (SdS) metric, which is obtained after make a planar coordinate transformation on a 5D Ricci-flat Schwarzschild-de Sitter (SdS) static metric. We obtain the important result that the spectrum of fluctuations at zeroth order is independent of the scalar field mass M on Schwarzschild scales, while on cosmological scales it exhibits a mass dependence. However, in the first-order expansion, the spectrum depends of the inflaton mass and the amplitude is linear with the Black-Hole (BH) mass m.

  1. Alleviating anastrozole induced bone toxicity by selenium nanoparticles in SD rats

    SciTech Connect

    Vekariya, Kiritkumar K.; Kaur, Jasmine; Tikoo, Kulbhushan

    2013-04-15

    Aromatase inhibitors like anastrozole play an undisputed key role in the treatment of breast cancer, but on the other hand, various side effects like osteoporosis and increased risk of bone fracture accompany the chronic administration of these drugs. Here we show for the first time that selenium nanoparticles, when given in conjugation to anastrozole, lower the bone toxicity caused by anastrozole and thus reduce the probable damage to the bone. Selenium nanoparticles at a dose of 5 μg/ml significantly reduced the cell death caused by anastrozole (1 μM) in HOS (human osteoblast) cells. In addition, our results also highlighted that in female SD rat model, SeNPs (0.25, 0.5, 1 mg/kg/day) significantly prevented the decrease in bone density and increase in biochemical markers of bone resorption induced by anastrozole (0.2 mg/kg/day) treatment. Histopathological examination of the femurs of SeNP treated group revealed ossification, mineralization, calcified cartilaginous deposits and a marginal osteoclastic activity, all of which indicate a marked restorative action, suggesting the protective action of the SeNPs. Interestingly, SeNPs (1 mg/kg/day) also exhibited protective effect in ovariectomized rat model, by preventing osteoporosis, which signifies that bone loss due to estrogen deficiency can be effectively overcome by using SeNPs. - Highlights: ► SeNPs significantly reduce bone toxicity in anastrozole treated rats. ► SeNPs successfully prevented osteoporosis in ovariectomized rats. ► SeNP treatment lowered the levels of TRAP and increased the levels of ALKP.

  2. Improved Determination of the Atmospheric Parameters of the Pulsating sdB Star Feige 48

    NASA Astrophysics Data System (ADS)

    Latour, M.; Fontaine, G.; Green, E. M.; Brassard, P.; Chayer, P.

    2014-06-01

    As part of a multifaceted effort to better exploit the asteroseismological potential of the pulsating sdB star Feige 48, we present an improved spectroscopic analysis of that star based on new grids of NLTE, fully line-blanketed model atmospheres. To that end, we gathered four high signal-to-noise ratio time-averaged optical spectra of varying spectral resolutions from 1.0 Å to 8.7 Å, and we made use of the results of four independent studies to fix the abundances of the most important metals in the atmosphere of Feige 48. The mean atmospheric parameters we obtained from our four spectra of Feige 48 are: T eff = 29,850 ± 60 K, log g = 5.46 ± 0.01, and log N(He)/N(H) = -2.88 ± 0.02. We also modeled, for the first time, the He II line at 1640 Å from the STIS archive spectrum of the star, and with this line we found an effective temperature and a surface gravity that match well with the values obtained with the optical data. With some fine tuning of the abundances of the metals visible in the optical domain, we were able to achieve a very good agreement between our best available spectrum and our best-fitting synthetic one. Our derived atmospheric parameters for Feige 48 are in rather good agreement with previous estimates based on less sophisticated models. This underlines the relatively small effects of the NLTE approach combined with line blanketing in the atmosphere of this particular star, implying that the current estimates of the atmospheric parameters of Feige 48 are reliable and secure.

  3. Improved determination of the atmospheric parameters of the pulsating sdB star Feige 48

    SciTech Connect

    Latour, M.; Fontaine, G.; Brassard, P.; Green, E. M.; Chayer, P.

    2014-06-10

    As part of a multifaceted effort to better exploit the asteroseismological potential of the pulsating sdB star Feige 48, we present an improved spectroscopic analysis of that star based on new grids of NLTE, fully line-blanketed model atmospheres. To that end, we gathered four high signal-to-noise ratio time-averaged optical spectra of varying spectral resolutions from 1.0 Å to 8.7 Å, and we made use of the results of four independent studies to fix the abundances of the most important metals in the atmosphere of Feige 48. The mean atmospheric parameters we obtained from our four spectra of Feige 48 are: T {sub eff} = 29,850 ± 60 K, log g = 5.46 ± 0.01, and log N(He)/N(H) = –2.88 ± 0.02. We also modeled, for the first time, the He II line at 1640 Å from the STIS archive spectrum of the star, and with this line we found an effective temperature and a surface gravity that match well with the values obtained with the optical data. With some fine tuning of the abundances of the metals visible in the optical domain, we were able to achieve a very good agreement between our best available spectrum and our best-fitting synthetic one. Our derived atmospheric parameters for Feige 48 are in rather good agreement with previous estimates based on less sophisticated models. This underlines the relatively small effects of the NLTE approach combined with line blanketing in the atmosphere of this particular star, implying that the current estimates of the atmospheric parameters of Feige 48 are reliable and secure.

  4. Heterologous Expression and Characterization of the Manganese-Oxidizing Protein from Erythrobacter sp. Strain SD21

    PubMed Central

    Nakama, Katherine; Medina, Michael; Lien, Ahn; Ruggieri, Jordan; Collins, Krystle

    2014-01-01

    The manganese (Mn)-oxidizing protein (MopA) from Erythrobacter sp. strain SD21 is part of a unique enzymatic family that is capable of oxidizing soluble Mn(II). This enzyme contains two domains, an animal heme peroxidase domain, which contains the catalytic site, followed by a C-terminal calcium binding domain. Different from the bacterial Mn-oxidizing multicopper oxidase enzymes, little is known about MopA. To gain a better understanding of MopA and its role in Mn(II) oxidation, the 238-kDa full-length protein and a 105-kDa truncated protein containing only the animal heme peroxidase domain were cloned and heterologously expressed in Escherichia coli. Despite having sequence similarity to a peroxidase, hydrogen peroxide did not stimulate activity, nor was activity significantly decreased in the presence of catalase. Both pyrroloquinoline quinone (PQQ) and hemin increased Mn-oxidizing activity, and calcium was required. The Km for Mn(II) of the full-length protein in cell extract was similar to that of the natively expressed protein, but the Km value for the truncated protein in cell extract was approximately 6-fold higher than that of the full-length protein, suggesting that the calcium binding domain may aid in binding Mn(II). Characterization of the heterologously expressed MopA has provided additional insight into the mechanism of bacterial Mn(II) oxidation, which will aid in understanding the role of MopA and Mn oxidation in bioremediation and biogeochemical cycling. PMID:25172859

  5. Purification and Characterization of the Manganese(II) Oxidizing Protein from Erythrobacter sp. SD-21

    NASA Astrophysics Data System (ADS)

    Nakama, K. R.; Lien, A.; Johnson, H. A.

    2013-12-01

    The manganese(II) oxidizing protein (Mop) found in the alpha-proteobacterium Erythrobacter sp. SD-21 catalyzes the formation of insoluble Mn(III/IV) oxides from soluble Mn(II). These Mn(III/IV) oxides formed are one of the strongest naturally occurring oxides, next to oxygen, and can be used to adsorb and oxidize toxic chemicals from the surrounding environment. Because of the beneficial use in the treatment of contaminated sources, the mechanism and biochemical properties of this novel enzyme are being studied. Due to low expression levels in the native host strain, purification of Mop has been problematic. To overcome this problem the gene encoding Mop, mopA, was cloned from the native host into a C-terminal histidine tag vector and expressed in Escherichia coli cells. Affinity chromatography under denaturing conditions have been applied in attempts to purify an active Mop. Western blots have confirmed that the protein is being expressed and is at the expected size of 250 kDa. Preliminary characterization on crude extract containing Mop has shown a Km and vmax value of 2453 uM and 0.025 uM min-1, respectively. Heme and pyrroloquinoline quinone can stimulate Mn(II) oxidizing activity, but hydrogen peroxide does not affect activity, despite the sequence similarity to animal heme peroxidase proteins. Research has been shown that calcium is essential for Mop activity. Purifying an active Mn(II) oxidizing protein will allow for a better understanding behind the enigmatic process of Mn(II) oxidation.

  6. Heterologous expression and characterization of the manganese-oxidizing protein from Erythrobacter sp. strain SD21.

    PubMed

    Nakama, Katherine; Medina, Michael; Lien, Ahn; Ruggieri, Jordan; Collins, Krystle; Johnson, Hope A

    2014-11-01

    The manganese (Mn)-oxidizing protein (MopA) from Erythrobacter sp. strain SD21 is part of a unique enzymatic family that is capable of oxidizing soluble Mn(II). This enzyme contains two domains, an animal heme peroxidase domain, which contains the catalytic site, followed by a C-terminal calcium binding domain. Different from the bacterial Mn-oxidizing multicopper oxidase enzymes, little is known about MopA. To gain a better understanding of MopA and its role in Mn(II) oxidation, the 238-kDa full-length protein and a 105-kDa truncated protein containing only the animal heme peroxidase domain were cloned and heterologously expressed in Escherichia coli. Despite having sequence similarity to a peroxidase, hydrogen peroxide did not stimulate activity, nor was activity significantly decreased in the presence of catalase. Both pyrroloquinoline quinone (PQQ) and hemin increased Mn-oxidizing activity, and calcium was required. The Km for Mn(II) of the full-length protein in cell extract was similar to that of the natively expressed protein, but the Km value for the truncated protein in cell extract was approximately 6-fold higher than that of the full-length protein, suggesting that the calcium binding domain may aid in binding Mn(II). Characterization of the heterologously expressed MopA has provided additional insight into the mechanism of bacterial Mn(II) oxidation, which will aid in understanding the role of MopA and Mn oxidation in bioremediation and biogeochemical cycling. PMID:25172859

  7. Further comments on the application of the method of averaging to the study of the rotational motions of a triaxial rigid body, part 3

    NASA Technical Reports Server (NTRS)

    Liu, J. J. F.; Fitzpatrick, P. M.

    1973-01-01

    Variational equations were applied to the case of a rapidly spinning triaxial body moving in an elliptic orbit, in which the orbital plane is regressing at a constant rate. The explicit differential equations obtained in this application were integrated by the method of averaging to develop secular analytical expressions, which, to first-order in a small parameter, describe the complete space motions of the rigid body under the influence of nonresonant gravity-gradient perturbations. The effects of aerodynamic torque on the rotational motion of an orbiting satellite are studied, as another example of the application of the variational equations derived and the method of averaging.

  8. Rapid, Accurate, and Non-Invasive Measurement of Zebrafish Axial Length and Other Eye Dimensions Using SD-OCT Allows Longitudinal Analysis of Myopia and Emmetropization

    PubMed Central

    Collery, Ross F.; Veth, Kerry N.; Dubis, Adam M.; Carroll, Joseph; Link, Brian A.

    2014-01-01

    Refractive errors in vision can be caused by aberrant axial length of the eye, irregular corneal shape, or lens abnormalities. Causes of eye length overgrowth include multiple genetic loci, and visual parameters. We evaluate zebrafish as a potential animal model for studies of the genetic, cellular, and signaling basis of emmetropization and myopia. Axial length and other eye dimensions of zebrafish were measured using spectral domain-optical coherence tomography (SD-OCT). We used ocular lens and body metrics to normalize and compare eye size and relative refractive error (difference between observed retinal radial length and controls) in wild-type and lrp2 zebrafish. Zebrafish were dark-reared to assess effects of visual deprivation on eye size. Two relative measurements, ocular axial length to body length and axial length to lens diameter, were found to accurately normalize comparisons of eye sizes between different sized fish (R2 = 0.9548, R2 = 0.9921). Ray-traced focal lengths of wild-type zebrafish lenses were equal to their retinal radii, while lrp2 eyes had longer retinal radii than focal lengths. Both genetic mutation (lrp2) and environmental manipulation (dark-rearing) caused elongated eye axes. lrp2 mutants had relative refractive errors of −0.327 compared to wild-types, and dark-reared wild-type fish had relative refractive errors of −0.132 compared to light-reared siblings. Therefore, zebrafish eye anatomy (axial length, lens radius, retinal radius) can be rapidly and accurately measured by SD-OCT, facilitating longitudinal studies of regulated eye growth and emmetropization. Specifically, genes homologous to human myopia candidates may be modified, inactivated or overexpressed in zebrafish, and myopia-sensitizing conditions used to probe gene-environment interactions. Our studies provide foundation for such investigations into genetic contributions that control eye size and impact refractive errors. PMID:25334040

  9. Low strength of Earth's uppermost mantle inferred from tri-axial deformation experiments on dry olivine crystals

    NASA Astrophysics Data System (ADS)

    Demouchy, Sylvie; Tommasi, Andréa; Boffa Ballaran, Tiziana; Cordier, Patrick

    2013-07-01

    We have performed tri-axial compression experiments on single crystals of San Carlos olivine with various orientations at temperatures relevant for the uppermost mantle, between 800 and 1090 °C. The experiments were carried out at a confining pressure of 300 MPa in a high-resolution gas-medium mechanical testing apparatus at various constant strain rates (from 7 × 10-6 s-1 to 1 × 10-4 s-1); they yield differential stresses ranging from 88 to 754 MPa. Unpolarized infrared spectroscopy analyses indicate that hydrogen concentration in the olivine lattice is very low (<0.5 ppm wt H2O) both before and after deformation. Transmission electron microscopy confirms plastic deformation by dislocation glide. [0 0 1] glide dominates regardless of the orientation of the crystals, even if very marginal [1 0 0] glide has also been activated in some samples. Orientation mapping by electron backscatter diffraction highlights significant local deviations from the original orientation in some samples associated with bending and deformation bands. These strain localizations suggest a heterogeneous mechanical behavior in this temperature range, which is favored by the strong mechanical anisotropy of the olivine crystal. The present experiments confirm that previous published high-temperature flow laws (i.e., power flow law) overestimate the strength of lithospheric mantle, since all samples deformed under stresses significantly lower than predicted by these flow laws. Based on the present results and on a compilation of previously published data on olivine deformation between 500 and 1000 °C, we propose a new semi-empirical exponential flow law applicable to the uppermost mantle: ɛ˙=1±0.2×106exp-{450±60×103}/{RT}12 where T is the absolute temperature, R is the gas constant, and σ is the differential stress in GPa. Subsequently, small fractions of melt or incorporation of hydrogen in olivine may not be required to reconcile natural observations indicating a limited strength

  10. Triaxial modulation of the acceleration induced in the lower extremity during whole-body vibration training: a pilot study.

    PubMed

    Cook, David P; Mileva, Katya N; James, Darren C; Zaidell, Lisa N; Goss, Victor G; Bowtell, Joanna L

    2011-02-01

    The purpose of the present study was to quantify vibration transmissibility through the lower extremity during exercise on a whole-body vibration (WBV) platform. Six healthy adults completed 20 trials of 30-second static squat exercise at 30 or 40 degrees of knee flexion angle on a WBV platform working at combinations of 5 frequencies (VF: 20, 25, 30, 35, 40 Hz) and 2 amplitudes (VA: low, 1.5 mm or high, 3 mm). Accelerations induced by the platform were recorded simultaneously at the shank and the thigh using triaxial accelerometers positioned at the segmental center of mass. Root-mean-square (RMS) acceleration amplitude and transmission ratios between the platform and the leg segments were calculated and compared between the experimental conditions. An alpha level of 0.05 was set to establish significance. Shank vertical acceleration was greatest at the lower VF (p = 0.028), higher VA (p = 0.028), and deeper squat (p = 0.048). Thigh vertical acceleration was not affected by depth of squat (p = 0.25), but it was greatest at higher VA (p = 0.046) and lower VF (p = 0.028). Medial-lateral shank acceleration was greatest at higher VF and deeper squat (both p = 0.046) and at higher VA (p = 0.028). Medial-lateral thigh acceleration was positively related to both VF (p = 0.046) and VA (p = 0.028) but was not affected by knee angle (p = 0.46). Anterior-posterior shank acceleration was higher at deeper squat (p = 0.046) and at lower VF and higher VA (both p = 0.028). Anterior-posterior thigh acceleration was related positively to the VA (p = 0.028), inversely to the VF (p = 0.028), and not dependent on knee angle (p = 0.75). Identification of specific vibration parameters and posture, which underpin WBV training efficacy, will enable coaches and athletes to design WBV training programs to specifically target shank or thigh muscles for enhanced performance. PMID:20040893

  11. Deformation and Brittle Failure of Folded Gneiss in Triaxial Compression: Failure Modes, Acoustic Signatures and Microfabric Controls

    NASA Astrophysics Data System (ADS)

    Agliardi, F.; Vinciguerra, S.; Dobbs, M. R.; Zanchetta, S.

    2014-12-01

    Fabric anisotropy is a key control of rock behavior in different geological settings and over different timescales. However, the effect of tectonically folded fabrics on the brittle strength and failure mode of metamorphic rocks is poorly understood. Recent data, obtained from uniaxial compression experiments on folded gneiss (Agliardi et al., 2014), demonstrated that their brittle failure modes depend upon the arrangement of two anisotropies (i.e. foliation and fold axial planes) and that rock strength correlates with failure mode. Since lithostatic pressure may significantly affect this rock behavior, we investigated its effect in triaxial compression experiments. We tested the Monte Canale Gneiss (Italian Alps), characterized by low phyllosilicate content and compositional layering folded at the cm-scale. We used a servo-controlled hydraulic loading system to test 19 air-dry cylindrical specimens (ø = 54 mm) that were characterized both in terms of fold geometry and orientation of foliation and fold axial planes to the axial load direction. The specimens were instrumented with direct contact axial and circumferential strain gauges. Acoustic emissions and P- and S-wave velocities were measured by piezoelectric transducers mounted in the compression platens. The tests were performed at confining pressures of 40 MPa and axial strain rates of 5*10-6 s-1. Post-failure study of fracture mechanisms and related microfabric controls was undertaken using X-ray CT, optical microscopy and SEM. Samples failed in three distinct brittle modes produced by different combinations of fractures parallel to foliation, fractures parallel to fold axial planes, or mm-scale shear bands. The failure modes, consistent with those described in uniaxial compression experiments, were found to be associated with distinct stress-strain and acoustic emission signatures. Failure modes involving quartz-dominated axial plane anisotropy correspond to higher peak strength and axial strain, less

  12. Identification of a New Marine Bacterial Strain SD8 and Optimization of Its Culture Conditions for Producing Alkaline Protease

    PubMed Central

    Cui, Hongxia; Yang, Muyang; Wang, Liping; Xian, Cory J.

    2015-01-01

    While much attention has been given to marine microorganisms for production of enzymes, which in general are relatively more stable and active compared to those from plants and animals, studies on alkaline protease production from marine microorganisms have been very limited. In the present study, the alkaline protease producing marine bacterial strain SD8 isolated from sea muds in the Geziwo Qinhuangdao sea area of China was characterized and its optimal culture conditions were investigated. Strain SD8 was initially classified to belong to genus Pseudomonas by morphological, physiological and biochemical characterizations, and then through 16S rDNA sequence it was identified to be likely Pseudomonas hibiscicola. In addition, the culture mediums, carbon sources and culture conditions of strain SD8 were optimized for maximum production of alkaline protease. Optimum enzyme production (236U/mL when cultured bacteria being at 0.75 mg dry weight/mL fermentation broth) was obtained when the isolate at a 3% inoculum size was grown in LB medium at 20 mL medium/100mL Erlenmeyer flask for 48h culture at 30°C with an initial of pH 7.5. This was the first report of strain Pseudomonas hibiscicola secreting alkaline protease, and the data for its optimal cultural conditions for alkaline protease production has laid a foundation for future exploration for the potential use of SD8 strain for alkaline protease production. PMID:26716833

  13. 76 FR 58241 - Designation for the Aberdeen, SD; Decatur, IL; Hastings, NE; Fulton, IL; the State of Missouri...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-20

    ..., Federal Register (76 FR 15937), GIPSA requested applications for designation to provide official services... Grain Inspection, Packers and Stockyards Administration Designation for the Aberdeen, SD; Decatur, IL; Hastings, NE; Fulton, IL; the State of Missouri, and the State of South Carolina Areas AGENCY:...

  14. Identification of a New Marine Bacterial Strain SD8 and Optimization of Its Culture Conditions for Producing Alkaline Protease.

    PubMed

    Cui, Hongxia; Yang, Muyang; Wang, Liping; Xian, Cory J

    2015-01-01

    While much attention has been given to marine microorganisms for production of enzymes, which in general are relatively more stable and active compared to those from plants and animals, studies on alkaline protease production from marine microorganisms have been very limited. In the present study, the alkaline protease producing marine bacterial strain SD8 isolated from sea muds in the Geziwo Qinhuangdao sea area of China was characterized and its optimal culture conditions were investigated. Strain SD8 was initially classified to belong to genus Pseudomonas by morphological, physiological and biochemical characterizations, and then through 16S rDNA sequence it was identified to be likely Pseudomonas hibiscicola. In addition, the culture mediums, carbon sources and culture conditions of strain SD8 were optimized for maximum production of alkaline protease. Optimum enzyme production (236U/mL when cultured bacteria being at 0.75 mg dry weight/mL fermentation broth) was obtained when the isolate at a 3% inoculum size was grown in LB medium at 20 mL medium/100mL Erlenmeyer flask for 48h culture at 30°C with an initial of pH 7.5. This was the first report of strain Pseudomonas hibiscicola secreting alkaline protease, and the data for its optimal cultural conditions for alkaline protease production has laid a foundation for future exploration for the potential use of SD8 strain for alkaline protease production. PMID:26716833

  15. Application of chirally-deuterated (S)-D-(6-2H1)glucose to conformational studies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Deuterated sugars are widely used to elucidate mechanisms of biosynthesis and of chemical reactions, and to confirm assignments of complex NMR or mass spectra. To date, however, there are few reported syntheses for regio and stereospecifically deuterated pyranoses. Chirally-deuterated (S)-D-(6-**2...

  16. Nocardiopsis sp. SD5: a potent feather degrading rare actinobacterium isolated from feather waste in Tamil Nadu, India.

    PubMed

    Saha, Subhasish; Dhanasekaran, D; Shanmugapriya, S; Latha, S

    2013-07-01

    Feather waste, generated in large quantities as a byproduct of commercial poultry processing, is nearly pure keratin protein, and keratin in its native state is not degradable by common proteolytic enzymes. The aim of the study was to find a potent feather degrading actinobacteria from feather waste soil. Out of 91 actinobacterial isolates recorded from feather waste soil in Tiruchirappalli and Nammakkal District, Tamil Nadu, India, isolate SD5 was selected for characterization because it exhibited significant keratinolytic activity. On the basis of the phenotypic, biochemical characterization and 16S rRNA gene-sequencing studies, the isolate was identified as Nocardiopsis sp. SD5. Protease and keratinase activity of Nocardiopsis sp. SD5 were analyzed. The enzyme was more stable over the neutral pH and the temperature of 40 °C. The optimum temperature and pH for both proteolytic and keratinolytic activity was determined at 50 °C and pH 9, respectively. Enzyme inhibitors, detergents and chelator declined the enzyme activity with increasing concentration. Nondenaturing polyacrylamide gel electrophoresis and zymogram elucidated the presence of 30 and 60 kDa protease enzymes. These findings indicated that thermo alkaliphilic feather degrading strain Nocardiopsis sp. SD5 could be used to control the feather waste pollution and to convert keratin rich feather waste into useful feedstock for poultry industry. PMID:23864545

  17. Nocardiopsis sp. SD5: A potent feather degrading rare actinobacterium isolated from feather waste in Tamil Nadu, India.

    PubMed

    Saha, Subhasish; Dhanasekaran, D; Shanmugapriya, S; Latha, S

    2012-08-23

    Feather waste, generated in large quantities as a byproduct of commercial poultry processing, is nearly pure keratin protein, and keratin in its native state is not degradable by common proteolytic enzymes. The aim of the study was to find a potent feather degrading actinobacteria from feather waste soil. Out of 91 actinobacterial isolates recorded from feather waste soil in Tiruchirappalli and Nammakkal District, Tamil Nadu, India, isolate SD5 was selected for characterization because it exhibited significant keratinolytic activity. On the basis of the phenotypic, biochemical characterization and 16S rRNA gene-sequencing studies, the isolate was identified as Nocardiopsis sp. SD5. Protease and keratinase activity of Nocardiopsis sp. SD5 were analyzed. The enzyme was more stable over the neutral pH and the temperature of 40 °C. The optimum temperature and pH for both proteolytic and keratinolytic activity was determined at 50 °C and pH 9, respectively. Enzyme inhibitors, detergents and chelator declined the enzyme activity with increasing concentration. Non denaturing poly acrylamide gel electrophoresis and zymogram elucidated the presence of 30 kda and 60 kda protease enzymes. These findings indicated that thermo alkaliphilic feather degrading strain Nocardiopsis sp. SD5 could be used to control the feather waste pollution and to convert keratin rich feather waste into useful feedstock for poultry industry. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim). PMID:22914902

  18. HS 2333+3927: A new sdB+dM binary with a large reflection effect

    NASA Astrophysics Data System (ADS)

    Heber, U.; Drechsel, H.; Østensen, R.; Karl, C.; Napiwotzki, R.; Altmann, M.; Cordes, O.; Solheim, J.-E.; Voss, B.; Koester, D.; Folkes, S.

    2004-06-01

    We have discovered periodic light variations (P = 0.1718023 d) in the sdB star HS 2333+3927 in the BVR bands with amplitudes of 0.21, 0.28 and 0.33 mag, respectively. Sinusoidal radial velocity variations at the same period were detected with a semi-amplitude of K1 = 89.6 km s-1, indicating that it is binary system and that the light variations are caused by the reflection effect with no eclipses. A mass function of f(m)= 0.0128 M⊙ has been determined. The analysis of the light curve did not yield a unique solution, mainly because the albedo of the secondary is poorly constrained. Two solutions of equal quality with a high (A2= 1.0) and a low (A2= 0.39) albedo were considered further. Variability of the Balmer line profiles, most notably for Hα, was discovered, probably also caused by the reflection effect. A spectroscopic analysis results in Teff = 36 500 K, log g = 5.70, and log (nHe/nH) = -2.15. These characteristics are typical for sdB stars. Mass-radius relations are derived from the results of the analysis of light and radial-velocity curves. Comparison with the observed mass-radius relation of the sdB star and with that of lower main sequence stars for the companion allows us to discard the high albedo solution, because the resulting mass of the primary and the radius of the secondary would be unreasonably low. From a discussion of evolutionary models we constrain the plausible mass of the sdB to the range between 0.29 M⊙ and 0.47 M⊙. Accordingly, the mass of the secondary is between 0.24 M⊙ and 0.32 M⊙, indicating a spectral type of M3 to M4. HS 2333+3927 is only the sixth sdB+dM system discovered so far. An improved measurement of the gravity and the projected rotational velocity of the sdB star is required to further constrain the masses and to identify the evolutionary state of the sdB star uniquely. Based on observations obtained at the German-Spanish Astronomical Center (DSAZ) at Calar Alto, the Nordic Optical Telescope (NOT) and the Jacobus

  19. Io's triaxial figure.

    NASA Technical Reports Server (NTRS)

    O'Leary, B.; Van Flandern, T. C.

    1972-01-01

    Timings from photoelectric observations of four immersions and two emersions of the recent occultation of Beta Scorpii C by Io have made it possible to derive Io's apparent equatorial radius to an accuracy of 2 km. However, when the distortion of Io attributable to rotation and tides raised by Jupiter is considered, the derived mean radius becomes several kilometers less than the observed equatorial radius. If Io were a homogeneous fluid body in hydrostatic equilibrium and in synchronous rotation, it would show a bulge along a line to Jupiter about 20 km in radius greater than the polar radius. The mean radius thus derived is (1818 plus or minus 5) km and mean density (2.88 plus or minus 0.34) g/cu cm, the largest uncertainty being attributable to the value of Io's mass. The new value for Io's radius is higher than those previously determined and suggests about 30% lower values for mean densities of all Galilean satellites.

  20. A CHANDRA OBSERVATION OF THE NEARBY SCULPTOR GROUP Sd GALAXY NGC 7793

    SciTech Connect

    Pannuti, Thomas G.; Staggs, Wayne D.; Schlegel, Eric M.; Filipovic, Miroslav D.; Payne, Jeffrey L.; Petre, Robert

    2011-07-15

    We conducted a Chandra ACIS observation of the nearby Sculptor Group Sd galaxy NGC 7793 as part of a multiwavelength study of supernova remnants (SNRs) in nearby galaxies. At the assumed distance to NGC 7793 of 3.91 Mpc, the limiting unabsorbed luminosity of the detected discrete X-ray sources is L{sub X} (0.2-10.0 keV) {approx}3x10{sup 36} erg s{sup -1}. A total of 22 discrete sources were detected at the {approx}3{sigma} level or greater including one ultraluminous X-ray source (ULX). Based on multiwavelength comparisons, we identify X-ray sources coincident with one SNR, the candidate microquasar N7793-S26, one H II region, and two foreground Galactic stars. We also find that the X-ray counterpart to the candidate radio SNR R3 is time variable in its X-ray emission: we therefore rule out the possibility that this source is a single SNR. A marked asymmetry is seen in the distribution of the discrete sources with the majority lying in the eastern half of this galaxy. All of the sources were analyzed using quantiles to estimate spectral properties and spectra of the four brightest sources (including the ULX) were extracted and analyzed. We searched for time variability in the X-ray emission of the detected discrete sources using our measured fluxes along with fluxes measured from prior Einstein and Roentgensatellit observations. From this study, three discrete X-ray sources are established to be significantly variable. A spectral analysis of the galaxy's diffuse emission is characterized by a temperature of kT = 0.19-0.25 keV. The luminosity function of the discrete sources shows a slope with an absolute value of {Gamma} = -0.65 {+-} 0.11 if we exclude the ULX. If the ULX is included, the luminosity function has a long tail to high L{sub X} with a poor-fitting slope of {Gamma} = -0.62 {+-} 0.2. The ULX-less slope is comparable to the slopes measured for the distributions of NGC 6946 and NGC 2403 but much shallower than the slopes measured for the distributions of

  1. High Brightness Picture Technology In SD-P40 Projection TV

    NASA Astrophysics Data System (ADS)

    Hasegawa, Shinichi

    1987-04-01

    Pioneer Electric Company has developed a new generation 40-inch rear projection SD-P40 television, a revolutionary, new television that realizes white peak brightness of 300 ft-I and high contrast. The combination of high brightness and high contrast is made possible primarily by newly developed optical-coupling technology that utilizes newly developed concepts. This new optical coupling technology cools the CRT quite efficiently, making it possible to greatly increase the CRT power input to obtain high brightness and at the same time provides greater reliability than direct view televisions. The new optical-coupling technology also makes it possible to almost completely eliminate the reflectance at the boundaries between the CRT and the lens and air, which gives much higher contrast than previous televisions. Not only does this optical-coupling technology provide high performance, in addition since the liquid coolant it employs functions as a liquid lens, the coupling lens can be designed to a uniform thinness and a small aperture. This greatly reduces the cost of the lens. Our newly developed optical-coupling technology is the ultimate form of cooling for the CRT tubes of projection televisions and coupling with the lens and will become the mainstream technology in the future. It is forecast that other manufacturers will also adopt this type of technology. The optical lens section, which is the heart of a projection television, is a hybrid structure with three aspherical plastic lenses and one glass spherical lens. It has higher performance image formation and greater temperature stability than previous televisions. The plastic lenses are all finished with multi-coating to hold down light loss and maximize transparency. This con-tributes greatly to increasing the brightness for a projection television. Previous 3-tube type projection televisions were bothered by low color uniformity, color shift, and low color rela-tive illumination. This model uses three bends

  2. Data Qualification and Data Summary Report: Intact Rock Properties Data on Tensile Strength, Schmidt Hammer Rebound Hardness, and Rock Triaxial Creep

    SciTech Connect

    E.M. Cikanek; R.J. Blakely; T.A. Grant; L.E. Safley

    2003-07-29

    This report presents a systematic review of the available data in the TDMS that are relevant to the following intact rock properties: rock tensile strength, Schmidt hammer rebound hardness, and rock triaxial creep. Relevant data are compiled from qualified and unqualified sources into the summary DTNs and these DTNs are evaluated for qualification using the method of corroborating data as defined in AP-SIII.2Q, ''Qualification of Unqualified Data''. This report also presents a summary of the compiled information in the form of descriptive statistics and recommended values that will be contained in a Reference Information Base (RIB) item prepared in accordance with AP-SIII.4Q, ''Development, Review, Online Placement, and Maintenance of Individual Reference Information Base Data Items''. The primary purpose of this report is to produce qualified sets of data that include all relevant intact rock tensile strength, Schmidt hammer rebound hardness, and rock triaxial creep testing done over the course of the Yucca Mountain Project (YMP). A second purpose is to provide a qualified summary (i.e., a RIB data item) of the test results using descriptive statistics. The immediate purpose of the report is to support the data needs of repository design; however, the products are designed to be appropriate for general use by the YMP. The appropriateness and limitations, if any, of the data, with respect to the intended use, are addressed in this report.

  3. A real-time and self-calibrating algorithm based on triaxial accelerometer signals for the detection of human posture and activity.

    PubMed

    Curone, Davide; Bertolotti, Gian Mario; Cristiani, Andrea; Secco, Emanuele Lindo; Magenes, Giovanni

    2010-07-01

    Assessment of human activity and posture with triaxial accelerometers provides insightful information about the functional ability: classification of human activities in rehabilitation and elderly surveillance contexts has been already proposed in the literature. In the meanwhile, recent technological advances allow developing miniaturized wearable devices, integrated within garments, which may extend this assessment to novel tasks, such as real-time remote surveillance of workers and emergency operators intervening in harsh environments. We present an algorithm for human posture and activity-level detection, based on the real-time processing of the signals produced by one wearable triaxial accelerometer. The algorithm is independent of the sensor orientation with respect to the body. Furthermore, it associates to its outputs a "reliability" value, representing the classification quality, in order to launch reliable alarms only when effective dangerous conditions are detected. The system was tested on a customized device to estimate the computational resources needed for real-time functioning. Results exhibit an overall 96.2% accuracy when classifying both static and dynamic activities. PMID:20483689

  4. Focal thinning of the cerebral cortex in multiple sclerosis.

    PubMed

    Sailer, Michael; Fischl, Bruce; Salat, David; Tempelmann, Claus; Schönfeld, Mircea Ariel; Busa, Evelina; Bodammer, Nils; Heinze, Hans-Jochen; Dale, Anders

    2003-08-01

    Brain atrophy as determined by quantitative MRI can be used to characterize disease progression in multiple sclerosis. Many studies have addressed white matter (WM) alterations leading to atrophy, while changes of the cerebral cortex have been studied to a lesser extent. In vivo, the cerebral cortex has been difficult to study due to its complex structure and regional variability. Measurement of cerebral cortex thickness at different disease stages may provide new insights into grey matter (GM) pathology. In the present investigation, we evaluated in vivo cortical thickness and its relationship to disability, disease duration, WM T2 hyper-intense and T1 hypo-intense lesion volumes. High-resolution MRI brain scans were obtained in 20 patients with clinically definite multiple sclerosis and 15 age-matched normal subjects. A novel method of automated surface reconstruction yielded measurements of the cortical thickness for each subject's entire brain and computed cross-subject statistics based on the cortical anatomy. Statistical thickness difference maps were generated by performing t-tests between patient and control groups and individual thickness measures were submitted to analyses of variance to investigate the relationship between cortical thickness and clinical variables. The mean overall thickness of the cortical ribbon was reduced in multiple sclerosis patients compared with controls [2.30 mm (SD 0.14) versus 2.48 mm (SD 0.11)], showing a significant main effect of group (controls versus patients). In patients, we found significant main effects for disability, disease duration, T2 and T1 lesion volumes. The visualization of statistical difference maps of the cortical GM thickness on inflated brains across the cortical surface revealed a distinct distribution of significant focal thinning of the cerebral cortex in addition to the diffuse cortical atrophy. Focal cortical thinning in frontal [2.37 mm (SD 0.17) versus 2.73 mm (SD 0.25)] and in temporal [2.65 mm

  5. Southern galaxies. VIII - Surface photometry of the SD spiral NGC 7793

    NASA Astrophysics Data System (ADS)

    de Vaucouleurs, G.; Davoust, E.

    1980-08-01

    Detailed surface photometry in blue light of the SA(s)d galaxy NGC 7793, the faintest of the five major members of the Sculptor group, is obtained from photoelectrically calibrated Mount Stromlo and McDonald photographs. The luminosity distribution is dominated by an exponential disk of effective radius αe = 2'.11 = 1.92 kpc contributing 98.6% of the total luminosity BT = 9.51 ± 0.06. The corrected face-on magnitude BT0 = 9.13 corresponds to MT0 = -18.35 at the revised distance Δ = 3.1 Mpc (Appendix C). The spheroidal component visible only in the vicinity of the nucleus can be represented by an r1/4 law of effective radius rIe = 6".0 = 91 pc and total magnitude BTI = 14.13 or 1.4% of the total luminosity of the galaxy. The position angle of the major axis is 97°, the mean axis ratio is q = b/a = 0.61, and the inclination = 53°. The concentration indices C21 = 1.68 and C32 = 1.48 are consistent with the Sd classification. The integrated colors from UBV aperture photometry are essentially constant at = 0.56 ± 0.02, = -0.07 ± 0.02, the corrected face-on colors are (B - V)T0 = 0.46, (U - B)T0 = -0.15 in close agreement with the colors of M33 and the mean values for type Scd. A decomposition of the disk into an underlying old component and a young arm component shows that 65.570 of the total luminosity comes from the old component which has a corrected central luminosity μcα(0) = 21.06 and an effective radius re = 1'.76 = 1.60 kpc. The neutral H I mass MH = 0.67 × 109 Msun corresponds to a hydrogen-luminosity ratio MH/LB = 0.14 which is less than half the average for the morphological type and luminosity class of NGC 7793. The large number of H ii regions and the strength of the Hα emission in the disk suggest that a large fraction of the hydrogen is ionized. The integrated magnitude of the brightest superassociation (Hodge Nr 20) B, = 16.0 ± 0.1 is derived in Appendix A. The effect of resolution on the apparent peak brightness is illustrated in Appendix B

  6. Non extensive statistical physics applied in fracture-induced electric signals during triaxial deformation of Carrara marble

    NASA Astrophysics Data System (ADS)

    Cartwright-Taylor, Alexis; Vallianatos, Filippos; Sammonds, Peter

    2014-05-01

    We have conducted room-temperature, triaxial compression experiments on samples of Carrara marble, recording concurrently acoustic and electric current signals emitted during the deformation process as well as mechanical loading information and ultrasonic wave velocities. Our results reveal that in a dry non-piezoelectric rock under simulated crustal pressure conditions, a measurable electric current (nA) is generated within the stressed sample. The current is detected only in the region beyond (quasi-)linear elastic deformation; i.e. in the region of permanent deformation beyond the yield point of the material and in the presence of microcracking. Our results extend to shallow crustal conditions previous observations of electric current signals in quartz-free rocks undergoing uniaxial deformation and support the idea of a universal electrification mechanism related to deformation. Confining pressure conditions of our slow strain rate (10-6 s-1) experiments range from the purely brittle regime (10 MPa) to the semi-brittle transition (30-100MPa) where cataclastic flow is the dominant deformation mechanism. Electric current is generated under all confining pressures,implying the existence of a current-producing mechanism during both microfracture and frictional sliding. Some differences are seen in the current evolution between these two regimes, possibly related to crack localisation. In all cases, the measured electric current exhibits episodes of strong fluctuations over short timescales; calm periods punctuated by bursts of strong activity. For the analysis, we adopt an entropy-based statistical physics approach (Tsallis, 1988), particularly suited to the study of fracture related phenomena. We find that the probability distribution of normalised electric current fluctuations over short time intervals (0.5 s) can be well described by a q-Gaussian distribution of a form similar to that which describes turbulent flows. This approach yields different entropic

  7. Evaluation of Wave Propagation Properties during a True-Triaxial Rock Fracture Experiment using Acoustic Emission Frequency Characteristics

    NASA Astrophysics Data System (ADS)

    Goodfellow, S. D.; Ghofrani Tabari, M.; Nasseri, M. B.; Young, R.

    2013-12-01

    A true-triaxial deformation experiment was conducted to study the evolution of wave propagation properties by using frequency characteristics of AE waveforms to diagnose the state of fracturing in a sample of sandstone. Changes in waveform frequency content has been interpreted as either the generation of progressively larger fractures or the relative attenuation of high-frequency wave components as a result of micro-crack formation. A cubic sample of Fontainebleau sandstone was initially loaded to a stress state of σ1 = σ2 = 35 MPa, σ3 = 5 MPa at which point σ1¬ was increased until failure. Acoustic emission (AE) activity was monitored by 18 PZT transducers, three embedded in each platen. The sensor amplitude response spectrum was determined by following an absolute source calibration procedure and showed a relatively constant sensitivity in the frequency range between 20 kHz and 1200 kHz. Amplified waveforms were continuously recorded at a sampling rate of 10 MHz and 12-bit resolution. Continuous acoustic emission waveforms were harvested to extract discrete events. Using a time-varying transverse isotropic velocity model, 48,502 events were locatable inside the sample volume. Prior to peak-stress, AE activity was associated with stable quasi-static growth of fractures coplanar with σ1 and σ2 located near the platen boundaries. In the post peak-stress regime, fracture growth displays unstable ¬dynamic propagation. Analysis of waveform frequency characteristics was limited to the pre peak-stress regime. Analysis of AE frequency characteristics was conducted on all 48,502 located AE events; each event file containing 18 waveforms of varied quality. If the signal to noise ratio was greater than 5, the waveforms power spectrum was estimated and the source-receiver raypath vector was calculated. The power spectrum of each waveform was divided into three frequency bands (Low: 100 - 300 kHz, Medium: 300 - 600 kHz and High: 600 - 1000 kHz) and the power in each

  8. Multiple myeloma

    PubMed Central

    2010-01-01

    Abstract Advances in the imaging and treatment of multiple myeloma have occurred over the past decade. This article summarises the current status and highlights how an understanding of both is necessary for optimum management. PMID:20159661

  9. Multiple Sclerosis

    MedlinePlus

    Multiple sclerosis (MS) is a nervous system disease that affects your brain and spinal cord. It damages the myelin sheath, the ... and your body, leading to the symptoms of MS. They can include Visual disturbances Muscle weakness Trouble ...

  10. Multiple myeloma

    MedlinePlus

    Plasma cell dyscrasia; Plasma cell myeloma; Malignant plasmacytoma; Plasmacytoma of bone; Myeloma - multiple ... myeloma most commonly causes a low red blood cell count ( anemia ), which can lead to fatigue and ...

  11. Multiple myeloma.

    PubMed

    Raab, Marc S; Podar, Klaus; Breitkreutz, Iris; Richardson, Paul G; Anderson, Kenneth C

    2009-07-25

    Multiple myeloma is characterised by clonal proliferation of malignant plasma cells, and mounting evidence indicates that the bone marrow microenvironment of tumour cells has a pivotal role in myeloma pathogenesis. This knowledge has already expanded treatment options for patients with multiple myeloma. Prototypic drugs thalidomide, bortezomib, and lenalidomide have each been approved for the treatment of this disease by targeting both multiple myeloma cells and the bone marrow microenvironment. Although benefit was first shown in relapsed and refractory disease, improved overall response, duration of response, and progression-free and overall survival can be achieved when these drugs are part of first-line regimens. This treatment framework promises to improve outcome not only for patients with multiple myeloma, but also with other haematological malignancies and solid tumours. PMID:19541364

  12. Multiple Sclerosis

    PubMed Central

    Hashimoto, S.A.; Jiwa, Theresa I.

    1991-01-01

    Successful management of patients with multiple sclerosis depends upon the involvement of the family physician. All contacts with either a multiple sclerosis clinic or a neurologist should be made at the instigation of the family practitioner. Constant contact with the family physician ensures that the individual receives proper care. While specialty care is needed for many of the symptoms, psychosocial problems are dealt with best by the individual's own family physician. PMID:21229090

  13. Fatty Acid Composition of Adipose Tissues in Obese Mice and SD Rats Fed with Isaria sinclairii Powder

    PubMed Central

    Ahn, Mi Young; Seo, Yun Jung; Ji, Sang Deok; Han, Jea Woong; Hwang, Jae Sam; Yun, Eun Young

    2010-01-01

    Isaria sinclairii (Cicada Dongchunghacho) was studied as a potential crude natural food in powdered form. The role of tissue fatty acids in relation to the anti-obesity effects of I. sinclairii (IS) was examined by feeding the powder to SD rats ad libitum at 0, 1.25, 2.5, 5 and 10% (calculated about 8 g/kg) of the feed for a period of 3 months and 6 months. The fatty acid composition profile as indicated GC-MS, showed significantly slight dose-dependent increases in the levels of unsaturated fatty acids, particularly, arachidonic acid (C20: 4n6) , oleic acid, linoleic acid, eicosadienoic acid, eicosapentaenoic acid (EPA) (C20: 5) concentration in the the ad libitum IS-fed groups compared to the control group in SD abdominal fat over 6 month period. Over viewing of the SD and Ob mice treated Isaria sinclairii powder; there were increases in the single (mono) unsaturated fatty acids ratio but decreases in polyunsaturated fatty acid. In IS-fed groups in proportion to the treatment period, this Dongchunghacho also induced an increase in the level of same result of unsaturated fatty acid in C57BL/6 obese (ob/ob) mice over a 6-month period treatment compared to those given 10% dry mulberry leaf powder (ML) or silkworm powder mixed with the standard diet. PMID:24278523

  14. Experimental Investigation on the Basic Law of the Fracture Spatial Morphology for Water Pressure Blasting in a Drillhole Under True Triaxial Stress

    NASA Astrophysics Data System (ADS)

    Huang, Bingxiang; Li, Pengfeng

    2015-07-01

    The present literature on the morphology of water pressure blasting fractures in drillholes is not sufficient and does not take triaxial confining stress into account. Because the spatial morphology of water pressure blasting fractures in drillholes is not clear, the operations lack an exact basis. Using a large true triaxial water pressure blasting experimental system and an acoustic emission 3-D positioning system, water pressure blasting experiments on cement mortar test blocks (300 mm × 300 mm × 300 mm) were conducted to study the associated basic law of the fracture spatial morphology. The experimental results show that water pressure blasting does not always generate bubble pulsation. After water pressure blasting under true triaxial stress, a crushed compressive zone and a blasting fracture zone are formed from the inside, with the blasting section of the naked drillhole as the center, to the outside. The shape of the outer edges of the two zones is ellipsoidal. The range of the blasting fracture is large in the radial direction of the drillhole, where the surrounding pressure is large, i.e., the range of the blasting fracture in the drillhole radial cross-section is approximately ellipsoidal. The rock near the drillhole wall is affected by a tensile stress wave caused by the test block boundary reflection, resulting in more flake fractures appearing in the fracturing crack surface in the drillhole axial direction and parallel to the boundary surface. The flake fracture is thin, presenting a small-range flake fracture. The spatial morphology of the water pressure blasting fracture in the drillhole along the axial direction is similar to a wide-mouth Chinese bottle: the crack extent is large near the drillhole orifice, gradually narrows inward along the drillhole axial direction, and then increases into an approximate ellipsoid in the internal naked blasting section. Based on the causes of the crack generation, the blasting cracks are divided into three

  15. Triaxially deformed relativistic point-coupling model for Λ hypernuclei: A quantitative analysis of the hyperon impurity effect on nuclear collective properties

    NASA Astrophysics Data System (ADS)

    Xue, W. X.; Yao, J. M.; Hagino, K.; Li, Z. P.; Mei, H.; Tanimura, Y.

    2015-02-01

    Background: The impurity effect of hyperons on atomic nuclei has received a renewed interest in nuclear physics since the first experimental observation of appreciable reduction of E 2 transition strength in low-lying states of the hypernucleus Λ7Li . Many more data on low-lying states of Λ hypernuclei will be measured soon for s d -shell nuclei, providing good opportunities to study the Λ impurity effect on nuclear low-energy excitations. Purpose: We carry out a quantitative analysis of the Λ hyperon impurity effect on the low-lying states of s d -shell nuclei at the beyond-mean-field level based on a relativistic point-coupling energy density functional (EDF), considering that the Λ hyperon is injected into the lowest positive-parity (Λs) and negative-parity (Λp) states. Method: We adopt a triaxially deformed relativistic mean-field (RMF) approach for hypernuclei and calculate the Λ binding energies of hypernuclei as well as the potential-energy surfaces (PESs) in the (β ,γ ) deformation plane. We also calculate the PESs for the Λ hypernuclei with good quantum numbers by using a microscopic particle rotor model (PRM) with the same relativistic EDF. The triaxially deformed RMF approach is further applied in order to determine the parameters of a five-dimensional collective Hamiltonian (5DCH) for the collective excitations of triaxially deformed core nuclei. Taking 25,27Mg Λ and Si31Λ as examples, we analyze the impurity effects of Λs and Λp on the low-lying states of the core nuclei. Results: We show that Λs increases the excitation energy of the 21+ state and decreases the E 2 transition strength from this state to the ground state by 12 %to17 % . On the other hand, Λp tends to develop pronounced energy minima with larger deformation, although it modifies the collective parameters in such a way that the collectivity of the core nucleus can be either increased or decreased. Conclusions: The quadrupole deformation significantly affects the

  16. Using asymmetry analysis to reduce normal variability of Spectral Domain Optical Coherence Tomography (SD-OCT) macular thickness

    NASA Astrophysics Data System (ADS)

    Alluwimi, Muhammed Saad

    Purpose: To investigate the use of asymmetry analysis to reduce normal between-subject variability of macular thickness measurements using SD-OCT. Methods: 63 volunteers free of eye disease were recruited: 33 young subjects (ages 21 to 35 years with mean and SD of 25 +/- 1.7), and 30 older subjects (ages 45 to 85 years with mean and SD of 66.7 +/- 9.0). All participants passed a comprehensive ophthalmic examination within the past two years. Macular images were gathered with the Spectralis OCT (V 5.4, Heidelberg Engineering, GmbH). The overlay 8x8 grid was manually centered on the fovea and aligned with the foveal-disc axis, then divided into five zones per hemifield following the method of Um et al (2012 IOVS 53:1139); asymmetry was computed as the difference between superior and inferior zone thicknesses. We assumed that the lowest variation and the highest density of ganglion cells will be found ~3° to 6° from the foveal center, corresponding to zones 1 and 2. For each zone and age group, between-subject standard deviations (SDs) were compared for retinal thickness (RT) versus asymmetry using an F-test. To account for repeated measures, a probability of p < 0.0125 was required for statistical significance. Axial length (AL) and corneal curvature (CC) were measured with an IOLMaster by the same operator and during the same imaging session. Results: For OD, asymmetry analysis reduced between-subject variability in zones 1 and 2 in both groups (F > 3.2, p < 0.001). SD for zone 1 dropped from 12.0 to 3.0 mum in the young group and from 11.7 to 2.6 mum in the older group. SD for zone 2 dropped from 13.6 to 5.3 mum (young) and from 11.1 to 5.8 mum (older). Combining all subjects, neither RT nor asymmetry showed a strong correlation with AL or CC (R2 < 0.01). Analysis for OS yielded the same pattern of results, as did asymmetry analyses between eyes (F > 3.8, p < 0.0001). Conclusions: Asymmetry analysis reduced between-subject variability. These findings demonstrate

  17. [Multiple meningiomas].

    PubMed

    Terrier, L-M; François, P

    2016-06-01

    Multiple meningiomas (MMs) or meningiomatosis are defined by the presence of at least 2 lesions that appear simultaneously or not, at different intracranial locations, without the association of neurofibromatosis. They present 1-9 % of meningiomas with a female predominance. The occurrence of multiple meningiomas is not clear. There are 2 main hypotheses for their development, one that supports the independent evolution of these tumors and the other, completely opposite, that suggests the propagation of tumor cells of a unique clone transformation, through cerebrospinal fluid. NF2 gene mutation is an important intrinsic risk factor in the etiology of multiple meningiomas and some exogenous risk factors have been suspected but only ionizing radiation exposure has been proven. These tumors can grow anywhere in the skull but they are more frequently observed in supratentorial locations. Their histologic types are similar to unique meningiomas of psammomatous, fibroblastic, meningothelial or transitional type and in most cases are benign tumors. The prognosis of these tumors is eventually good and does not differ from the unique tumors except for the cases of radiation-induced multiple meningiomas, in the context of NF2 or when diagnosed in children where the outcome is less favorable. Each meningioma lesion should be dealt with individually and their multiple character should not justify their resection at all costs. PMID:27234913

  18. The qSD12 Underlying Gene Promotes Abscisic Acid Accumulation in Early Developing Seeds to Induce Primary Dormancy in Rice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seeds acquire primary dormancy during their development and the phytohormone abscisic acid (ABA) is considered to play a role in inducing the dormancy. qSD12 is a major seed dormancy QTL identified from weedy rice. This research was conducted to identify qSD12 candidate genes, isolate the candidat...

  19. Use of laboratory triaxial-creep data and finite-element analysis to predict observed creep behavior of leached salt caverns

    SciTech Connect

    Preece, D.S.; Stone, C.M.

    1982-08-01

    An increasing interest is being shown worldwide in using leached salt caverns to store oil and natural gas. A critical factor in the use of existing caverns and the design of new ones is the creep behavior of the salt surrounding the caverns. An understanding of this behavior is being gained by using laboratory triaxial creep data as material property input to finite element computer programs designed to calculate displacements and stresses due to creep. An important step in verifying these predictive methods is the comparison of field data from existing caverns with finite element analyses which incorporate the material properties and geometry of each site. This comparison has been made for caverns in the Eminence Dome (Mississippi), West Hackberry Dome (Louisiana), and Bayou Chocktaw Dome (Louisiana) with reasonably good correlation being obtained between measured and predicted volumetric response of the caverns. These comparisons are discussed in this paper.

  20. High-spin states in {sup 191,193}Au and {sup 192}Pt: Evidence for oblate deformation and triaxial shapes

    SciTech Connect

    Oktem, Y.; Akkus, B.; Bostan, M.; Cakirli, R. B.; Erduran, M. N.; Balabanski, D. L.; Beausang, C. W.; Casten, R. F.; Kruecken, R.; Novak, J. R.; Danchev, M.; Djongolov, M.; Riedinger, L. L.; Zeidan, O.; Erturk, S.; Gladniski, K. A.; Rainovski, G.; Guerdal, G.; Goon, J. Tm.; Hartley, D. J.

    2007-10-15

    High-spin states of {sup 191,193}Au and {sup 192}Pt have been populated in the {sup 186}W({sup 11}B, xn) and {sup 186}W({sup 11}B, p4n) reactions, respectively, at a beam energy of 68 MeV and their {gamma} decay was studied using the YRAST Ball detector array at the Wright Nuclear Structure Laboratory at Yale University. The level scheme of {sup 193}Au has been extended up to I{sup {pi}}=55/2{sup +}. New transitions were observed also in {sup 191}Au and {sup 192}Pt. Particle-plus-Triaxial-Rotor (PTR) and Total Routhian Surface (TRS) calculations were performed to determine the equilibrium deformations of the Au isotopes. The predictions for oblate deformations in these nuclei are in agreement with the experimental data. Development of nonaxial shapes is discussed within the framework of the PTR model.