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Sample records for lines including triaxial

  1. Triaxial strongly deformed bands in {sup 164}Hf and the effect of elevated yrast line

    SciTech Connect

    Ma Wenchao

    2012-10-20

    Two exotic rotational bands have been identified in {sup 164}Hf and linked to known states. They are interpreted as being associated with the calculated triaxial strongly deformed (TSD) potential energy minimum. The bands are substantially stronger and are located at much lower spins than the previously discovered TSD bands in {sup 168}Hf. In addition to the proton and neutron shell gaps at large trixiality, it was proposed that the relative excitation energy of TSD bands above the yrast line plays an important role in the population of TSD bands.

  2. Parachute Line Hook Includes Integral Loop Expander

    NASA Technical Reports Server (NTRS)

    Bayless, G. B.

    1983-01-01

    Parachute packing simplified with modified line hook. One person packs parachutes for test recovery vehicles faster than previously two-person team. New line hook includes expander that opens up two locking loops so parachute lines are pulled through them. Parachutes are packed at high pressure to be compressed into limited space available in test vehicles.

  3. Transmission line including support means with barriers

    DOEpatents

    Cookson, Alan H.

    1982-01-01

    A gas insulated transmission line includes an elongated outer sheath, a plurality of inner conductors disposed within and extending along the outer sheath, and an insulating gas which electrically insulates the inner conductors from the outer sheath. A support insulator insulatably supports the inner conductors within the outer sheath, with the support insulator comprising a main body portion including a plurality of legs extending to the outer sheath, and barrier portions which extend between the legs. The barrier portions have openings therein adjacent the main body portion through which the inner conductors extend.

  4. Inversion of Hipparcos photometric data using triaxial ellipsoid shape models including a Lommel-Seeliger scattering law

    NASA Astrophysics Data System (ADS)

    Cellino, A.; Muinonen, K.; Hestroffer, D.; Wilkman, O.

    2014-07-01

    Among the many expected results of the Gaia mission, there is an inversion of the sparse photometric data obtained during five years of operational lifetime for a number of asteroids of the order of 300,000. For each object, about 60--70 photometric measurements obtained in different epochs will be available. Gaia data will not consist of lightcurves (the most common product of ground-based photometry), but only of sets of ''photometric snapshots'' taken at very different epochs corresponding to very different observing circumstances. However, these data will all be taken by a single detector and without the problems affecting photometric observations performed from the ground (extinction, weather, etc.) and will also be intrinsically very accurate. Therefore we expect that, for most objects, it will be possible to invert the Gaia photometric data obtained, in order to derive from them basic information about the spin properties (rotation period, orientation of the spin axis), overall shape, and magnitude-phase angle relation. Since Gaia will observe such a large number of asteroids, the search for a compromise between required CPU time and adopted shape model is necessary. In particular, the choice has been forcedly that of assuming a regular triaxial ellipsoid model shape. Though not being very realistic, triaxial ellipsoid shapes are fairly flexible and constitute reasonable approximations of the real shapes in many cases, as shown also by numerical simulations (Torppa et al., 2008). The inversion of asteroid photometric data is performed using a genetic algorithm approach. This has been found to be satisfactorily performing through application to asteroid photometric data obtained years ago by the Hipparcos satellite (Cellino et al., 2009). In spite of being affected by large errors and also limited in terms of numbers of observations per object, application of the genetic algorithm developed for Gaia has been shown to be able to correctly invert Hipparcos data

  5. 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.

  6. Looking South at North End of Rod Loading Line Including ...

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

    Looking South at North End of Rod Loading Line Including Welding Area Within Rod Loading building - Hematite Fuel Fabrication Facility, Rod Loading Building, 3300 State Road P, Festus, Jefferson County, MO

  7. Triaxiality in disk galaxies

    SciTech Connect

    Bertola, F.; Vietri, M.; Zeilinger, W.W. Roma, Osservatorio Astronomico, Rome European Southern Observatory, Garching )

    1991-06-01

    Thirty-two bulges of nearby spirals have been observed, to detect misalignment between disk and bulge apparent major axes. Such misalignment is unequivocally present in the majority of observed objects. This may be due to the triaxiality of disks, bulges, or both. The probability distribution function for the axial ratios is derived under the two extreme hypotheses, i.e., that either only disks (case I) or only bulges (case II) are triaxial: the observational data are equally well fitted by either one. Since dynamical evidence and the internal twisting of isophotes show that bulges are triaxial, case I is unlikely, but an intermediate case cannot be ruled out. These distribution functions are compared with available constraints; in particular, that of case II is projected and compared with the distribution of apparent ellipticities of minor-axis dust-lane ellipticals and of all ellipticals. Both tests show that the observed and derived distributions are consistent. 34 refs.

  8. LOSS ESTIMATE FOR ITER ECH TRANSMISSION LINE INCLUDING MULTIMODE PROPAGATION

    SciTech Connect

    Shapiro, Michael; Bigelow, Tim S; Caughman, John B; Rasmussen, David A

    2010-01-01

    The ITER electron cyclotron heating (ECH) transmission lines (TLs) are 63.5-mm-diam corrugated waveguides that will each carry 1 MW of power at 170 GHz. The TL is defined here as the corrugated wave guide system connecting the gyrotron mirror optics unit (MO U) to the entrance of the ECH launcher and includes miter bends and other corrugated wave guide components. The losses on the ITER TL have been calculated for four possible cases corresponding to having HE(11) mode purity at the input of the TL of 100, 97, 90, and 80%. The losses due to coupling, ohmic, and mode conversion loss are evaluated in detail using a numerical code and analytical approaches. Estimates of the calorimetric loss on the line show that the output power is reduced by about 5, +/- 1% because of ohmic loss in each of the four cases. Estimates of the mode conversion loss show that the fraction of output power in the HE(11) mode is similar to 3% smaller than the fraction of input power in the HE(11) mode. High output mode purity therefore can be achieved only with significantly higher input mode purity. Combining both ohmic and mode conversion loss, the efficiency of the TL from the gyrotron MOU to the ECH launcher can be roughly estimated in theory as 92% times the fraction of input power in the HE(11) mode.

  9. Standard line broadening impact theory for hydrogen including penetrating collisions

    NASA Astrophysics Data System (ADS)

    Alexiou, S.; Poquérusse, A.

    2005-10-01

    In recent years there has been significant interest in the emission spectra from high-density plasmas, as manifested by a number of experiments. At these high densities short range (small impact parameter) interactions become important and these cannot be adequately handled by the standard theory, whose predictions depend on some cutoffs, necessary to preserve unitarity, the long range approximation, and to ensure the validity of a semiclassical picture. Very recently, as a result of a debate concerning the broadening of isolated ion lines, the importance of penetration of bound electron wave functions by plasma electrons has been realized. By softening the interaction, penetration makes perturbative treatments more valid. The penetration effect has now been included analytically into the standard theory. It turns out that the integrations may be done in closed form in terms of the modified Bessel functions K0 and K1 . This work develops the new theory and applies it to experimental measurements.

  10. New protection method for HVDC lines including cables

    SciTech Connect

    Takeda, H.; Ayakawa, H.; Tsumenaga, N.; Sanpei, M.

    1995-10-01

    For the third project of the Hokkaido-Honshu HVDC Link in Japan, called the HVDC Link III project (rated at 250 kVdc-1,200 A-300 MW), the authors developed an HVDC transmission line protection method based on a new working principle that allows high-speed and highly sensitive detection of faults, enhancing reliability in the supply of electric power. In general, increasing the sensitivity of relays will lead to an increased likelihood of undesired operation whereas lowering the sensitivity will impair the responsiveness of the relays. The proposed method meets these apparently incompatible requirements very well. Basically classified as a differential scheme, the HVDC transmission line protection method compensates for a charging and discharging current that flows through the line-to-ground capacitance at times of voltage variations caused by a line fault or by the operation of dc power systems. The developed protection method is also characterized in that it uses current changes induced by voltage variations to restrain the operation of a relay. This configuration has made the proposed method far superior in responsiveness and sensitivity to the conventional protection method. A simulation using an EMTP (Electro-Magnetic Transients Program) was conducted on this method. Developed relay equipment embodying the new protection method was subjected to various verification tests, where this equipment was connected to a power system simulator, before being delivered to the HVDC Link III facility.

  11. Rotational kinematics and torques for triaxial bodies

    NASA Astrophysics Data System (ADS)

    Newman, William I.

    2013-03-01

    Precession of the orbit poles and spin poles for triaxial bodies, including the possibility of phase locking, is addressed here. We provide a simple derivation of the time-averaged gravitational potential and associated torque, thereby confirming the results of Gladman et al. (Gladman, B., Quinn, D., Nicholson, P., Rand, R. [1996]. Icarus 122, 166-192).

  12. 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

  13. Self-consistent triaxial models

    NASA Astrophysics Data System (ADS)

    Sanders, Jason L.; Evans, N. Wyn

    2015-11-01

    We present self-consistent triaxial stellar systems that have analytic distribution functions (DFs) expressed in terms of the actions. These provide triaxial density profiles with cores or cusps at the centre. They are the first self-consistent triaxial models with analytic DFs suitable for modelling giant ellipticals and dark haloes. Specifically, we study triaxial models that reproduce the Hernquist profile from Williams & Evans, as well as flattened isochrones of the form proposed by Binney. We explore the kinematics and orbital structure of these models in some detail. The models typically become more radially anisotropic on moving outwards, have velocity ellipsoids aligned in Cartesian coordinates in the centre and aligned in spherical polar coordinates in the outer parts. In projection, the ellipticity of the isophotes and the position angle of the major axis of our models generally changes with radius. So, a natural application is to elliptical galaxies that exhibit isophote twisting. As triaxial Stäckel models do not show isophote twists, our DFs are the first to generate mass density distributions that do exhibit this phenomenon, typically with a gradient of ≈10°/effective radius, which is comparable to the data. Triaxiality is a natural consequence of models that are susceptible to the radial orbit instability. We show how a family of spherical models with anisotropy profiles that transition from isotropic at the centre to radially anisotropic becomes unstable when the outer anisotropy is made sufficiently radial. Models with a larger outer anisotropy can be constructed but are found to be triaxial. We argue that the onset of the radial orbit instability can be identified with the transition point when adiabatic relaxation yields strongly triaxial rather than weakly spherical endpoints.

  14. Triaxial nuclear models and the outer crust of nonaccreting cold neutron stars

    SciTech Connect

    Guo Lu; Hempel, M.; Schaffner-Bielich, J.; Maruhn, J. A.

    2007-12-15

    The properties and composition of the outer crust of nonaccreting cold neutron stars are studied by applying the model of Baym, Pethick, and Sutherland (BPS) and taking into account for the first time triaxial deformations of nuclei. Two theoretical nuclear models, Hartree-Fock plus pairing in the BCS approximation (HF-BCS) with Skyrme SLy6 parametrization and Hartree-Fock-Bogolyubov (HFB) with Gogny D1S force, are used to calculate the nuclear masses. The two theoretical calculations are compared; points of comparison of the two calculations include their neutron drip lines, binding energies, magic neutron numbers, and the sequence of nuclei in the outer crust of nonaccreting cold neutron stars, with special emphasis on the effect of triaxial deformations. The BPS model is extended by higher-order corrections for the atomic binding, screening, exchange, and zero-point energies. The influence of the higher-order corrections on the sequence of the outer crust is investigated.

  15. 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

  16. Proton emission from triaxial nuclei

    SciTech Connect

    Delion, D.S.; Wyss, R.; Karlgren, D.; Liotta, R.J.

    2004-12-01

    Proton decay from triaxially deformed nuclei is investigated. The deformation parameters corresponding to the mother nucleus are determined microscopically and the calculated decay widths are used to probe the mean-field wave function. The proton wave function in the mother nucleus is described as a resonant state in a coupled-channel formalism. The decay width, as well as the angular distribution of the decaying particle, are evaluated and their dependence upon the triaxial deformation parameters is studied in the decay of {sup 161}Re and {sup 185}Bi. It is found that the decay width is very sensitive to the parameters defining the triaxial deformation while the angular distribution is a universal function which does not depend upon details of the nuclear structure.

  17. GALACTIC WARPS IN TRIAXIAL HALOS

    SciTech Connect

    Jeon, Myoungwon; Kim, Sungsoo S.; Ann, Hong Bae E-mail: sungsoo.kim@khu.ac.kr

    2009-05-10

    We study the behavior of galactic disks in triaxial halos both numerically and analytically to see if warps can be excited and sustained in triaxial potentials. We consider the following two scenarios: (1) galactic disks that are initially tilted relative to the equatorial plane of the halo (for a pedagogical purpose), and (2) tilted infall of dark matter relative to the equatorial plane of the disk and the halo. With numerical simulations of 100,000 disk particles in a fixed halo potential, we find that in triaxial halos, warps can be excited and sustained just as in spherical or axisymmetric halos but they show some oscillatory behavior and even can be transformed to a polar-ring system if the halo has a prolate-like triaxiality. The nonaxisymmetric component of the halo causes the disk to nutate, and the differential nutation between the inner and outer parts of the disk generally makes the magnitude of the warp slightly diminish and fluctuate. We also find that warps are relatively weaker in oblate and oblate-like triaxial halos, and since these halos are the halo configurations of disk galaxies inferred by cosmological simulations, our results are consistent with the fact that most of the observed warps are quite weak. We derive approximate formulae for the torques exerted on the disk by the triaxial halo and the dark matter torus, and with these formulae we successfully describe the behavior of the disks in our simulations. The techniques used in deriving these formulae could be applied for realistic halos with more complex structures.

  18. 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.

  19. New method for true-triaxial rock testing

    SciTech Connect

    Wawersik, W.R.; Carlson, L.W.; Holcomb, D.J.; Williams, R.J.

    1997-03-01

    Two new and related true-triaxial apparatus are described that make use of conventional triaxial pressure vessels in combination with specially configured, high-pressure hydraulic jacks inside these vessels. The development combines advantages not found in existing facilities, including a compact design, pore-pressure and flow-through capabilities, the ability to attain high principal stresses and principal stress differences, direct access to parts of the sample, and provisions to go to relatively large deformations without developing serious stress field inhomogeneities.

  20. Tidal streams in triaxial systems

    NASA Astrophysics Data System (ADS)

    Price-Whelan, Adrian M.; Johnston, Kathryn V.; Pearson, Sarah; Kupper, Andreas Hans Wilhelm

    2015-01-01

    Tidal streams form from the steady disruption of stellar systems orbiting within the gravitational field of some parent galaxy. Many streams and debris structures have been discovered in the halo of the Milky Way and have been used to model the potential of the Galaxy. However, few of these models have yet explored the properties of tidal debris in triaxial potentials. The existence of a variety of orbits, resonances, and chaotic regions in such potentials suggest that the morphologies and dispersal timescales of debris could differ significantly from the simpler spherical and oblate cases. In this work we use a series of N-body simulations of stellar systems over a range of masses of disruption in triaxial potentials to understand the influence of the nature and types of orbits on debris morphologies. Our results suggest that the mere existence of the multitude of thin streams already known to orbit the Milky Way provides significant constraints on the classes of triaxial potentials that provide a good representation for its dark matter halo.

  1. Spectral line parameters including line shapes in the 2ν3 Q branch of 12CH4

    NASA Astrophysics Data System (ADS)

    Devi, V. Malathy; Benner, D. Chris; Sung, Keeyoon; Brown, Linda R.; Crawford, Timothy J.; Yu, Shanshan; Smith, Mary Ann H.; Mantz, Arlan W.; Boudon, Vincent; Ismail, Syed

    2016-07-01

    In this study, we report the first experimental measurements of spectral line shape parameters (self- and air-broadened Lorentz half-widths, pressure-shifts, and line mixing (via off-diagonal relaxation matrix elements) coefficients and their temperature dependences, where appropriate) for transitions in the 2ν3 Q branch manifolds, Q(11)-Q(1) of methane (12CH4), in the 5996.5-6007-cm-1 region. The analysis included 23 high-resolution, high signal-to-noise laboratory absorption spectra recorded with the Bruker IFS-125HR Fourier transform spectrometer (FTS) at JPL. The experimental data were obtained using 12C-enriched 12CH4 and dilute mixtures of 12CH4 in dry air in the 130-296 K range using a room-temperature long path absorption cell and, two custom-built coolable cells. In the analysis, an interactive multispectrum fitting software was employed where all the 23 spectra (11 self-broadened and 12 air-broadened) were fit simultaneously. By carefully applying reasonable constraints to the parameters for severely blended lines, we were able to determine a self-consistent set of broadening, shift and line mixing (relaxation matrix coefficients) parameters for CH4-CH4 and CH4-air collisions. In the majority of cases, a quadratic speed dependence parameter common for all transitions in each Q(J) manifold was determined. However, temperature dependences of the Q branch line mixing parameter could not be determined from the present data. Since no other experimental line shape measurements have been reported for this Q-branch, the present results are compared to available values in the HITRAN2012 database.

  2. Umbilical-spinous line: a morphological term that should be included in the anatomical terminology

    PubMed Central

    Ríos, John

    2013-01-01

    We argue the need to include in the International Anatomical Terminology the term "Umbilical-spinous line" for its importance as a morphological referent in bioscopic and surface anatomy. Also, in order to avoid using eponyms, it is suggested that the traditional term "McBurney point" be replaced by "supra spinous point" as being more descriptive of location. PMID:24892620

  3. 45. MACHINE SHOP NORTH/NORTHEAST INCLUDING OVERHEAD LINE SHAFTING. MOSTLY BELT ...

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

    45. MACHINE SHOP NORTH/NORTHEAST INCLUDING OVERHEAD LINE SHAFTING. MOSTLY BELT DRIVEN WITH ONE ROPE DRIVEN LATHE IN MIDDLE GROUND. POWER COMES FROM KNIGHT TURBINE ON FAR WALL SHOWN IN K-77, 78 (42') - Knight Foundry, 13 Eureka Street, Sutter Creek, Amador County, CA

  4. Umbilical-spinous line: a morphological term that should be included in the anatomical terminology.

    PubMed

    Duque, Jorge Eduardo; Ríos, John

    2013-07-01

    We argue the need to include in the International Anatomical Terminology the term "Umbilical-spinous line" for its importance as a morphological referent in bioscopic and surface anatomy. Also, in order to avoid using eponyms, it is suggested that the traditional term "McBurney point" be replaced by "supra spinous point" as being more descriptive of location.

  5. 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.

  6. Data-Mining-Based Intelligent Differential Relaying for Transmission Lines Including UPFC and Wind Farms.

    PubMed

    Jena, Manas Kumar; Samantaray, Subhransu Ranjan

    2016-01-01

    This paper presents a data-mining-based intelligent differential relaying scheme for transmission lines, including flexible ac transmission system device, such as unified power flow controller (UPFC) and wind farms. Initially, the current and voltage signals are processed through extended Kalman filter phasor measurement unit for phasor estimation, and 21 potential features are computed at both ends of the line. Once the features are extracted at both ends, the corresponding differential features are derived. These differential features are fed to a data-mining model known as decision tree (DT) to provide the final relaying decision. The proposed technique has been extensively tested for single-circuit transmission line, including UPFC and wind farms with in-feed, double-circuit line with UPFC on one line and wind farm as one of the substations with wide variations in operating parameters. The test results obtained from simulation as well as in real-time digital simulator testing indicate that the DT-based intelligent differential relaying scheme is highly reliable and accurate with a response time of 2.25 cycles from the fault inception.

  7. 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

  8. The evolution of line-tied coronal arcades including a converging footpoint motion

    NASA Technical Reports Server (NTRS)

    Inhester, B.; Birn, J.; Hesse, M.

    1992-01-01

    It has been demonstrated in the past that single, 2D coronal arcades are very unlikely driven unstable by a simple shear of the photospheric footpoints of the magnetic field lines. By means of 2D, time-dependent MHD simulations, evidence is presented that a resistive instability can result if in addition to the footpoint shear a slow motion of the footpoints toward the photospheric neutral line is included. The photospheric footpoint velocity in this model is nonsingular and the shear dominates everywhere. Starting from a planar potential field geometry for the arcade, it is found that after some time a current sheet is formed which is unstable with respect to the tearing instability. The time of its onset scales with the logarithm of the magnetic diffusivity assumed in the calculation. In its nonlinear phase, a quasi-stationary situation arises in the vicinity of the x-line with an almost constant reconnection rate. The height of the x-line above the photosphere and the distance of the separatrix footpoints remain almost constant in this phase, while the helical flux tube, formed above the neutral line, continuously grows in size.

  9. 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.

  10. 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

  11. An MCMC fitting method for triaxial dark matter haloes

    NASA Astrophysics Data System (ADS)

    Corless, Virginia L.; King, Lindsay J.

    2008-11-01

    Measuring the 3D distribution of mass on galaxy cluster scales is a crucial test of the Λ cold dark matter (ΛCDM) model, providing constraints on the behaviour of dark matter. Recent work investigating mass distributions of individual galaxy clusters (e.g. Abell 1689) using weak and strong gravitational lensing has revealed potential inconsistencies between the predictions of structure formation models relating halo mass to concentration and those relationships as measured in massive clusters. However, such analyses employ simple spherical halo models while a growing body of work indicates that triaxial 3D halo structure is both common and important in parameter estimates. Though lensing is sensitive only to 2D projected structure and is thus incapable of independently constraining 3D models, the very strong assumptions about the symmetry of the lensing halo implied with circular or perturbative elliptical Navarro, Frenk & White (NFW) models are not physically motivated and lead to incorrect parameter estimates with significantly underestimated error bars. We here introduce a Markov Chain Monte Carlo (MCMC) method to fit fully triaxial models to weak lensing data that gives parameter and error estimates that fully incorporate the true uncertainty present in nature. Using weak lensing data alone, the fits are sensitive to the Bayesian priors on axis ratio; we explore the impact of various general and physically motivated priors, and emphasize the need for future work combining lensing data with other data types to fully constrain the 3D structure of galaxy clusters. Applying the MCMC triaxial fitting method to a population of NFW triaxial lenses drawn from the shape distribution of structure formation simulations, we find that including triaxiality cannot explain a population of massive, highly concentrated clusters within the framework of ΛCDM, but easily explains rare cases of apparently massive, highly concentrated, very efficient lensing clusters. Our MCMC

  12. Identification of animal movement patterns using tri-axial magnetometry.

    PubMed

    Williams, Hannah J; Holton, Mark D; Shepard, Emily L C; Largey, Nicola; Norman, Brad; Ryan, Peter G; Duriez, Olivier; Scantlebury, Michael; Quintana, Flavio; Magowan, Elizabeth A; Marks, Nikki J; Alagaili, Abdulaziz N; Bennett, Nigel C; Wilson, Rory P

    2017-01-01

    approach shows promise for helping researchers to identify and quantify behaviours in terms of animal body posture, including heading. Magnetometer-based techniques and metrics can enhance our capacity to identify and examine animal behaviour, either as a technique used alone, or one that is complementary to tri-axial accelerometry.

  13. 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

  14. Variation after projection with a triaxially deformed nuclear mean field

    NASA Astrophysics Data System (ADS)

    Gao, Zao-Chun; Horoi, Mihai; Chen, Y. S.

    2015-12-01

    We implemented a variation after projection (VAP) algorithm based on a triaxially deformed Hartree-Fock-Bogoliubov vacuum state. This is the first projected mean field study that includes all the quantum numbers (except parity), i.e., spin (J ), isospin (T ), and mass number (A ). Systematic VAP calculations with JTA projection have been performed for the even-even s d -shell nuclei with the USDB Hamiltonian. All the VAP ground state energies are within 500 keV above the exact shell model values. Our VAP calculations show that the spin projection has two important effects: (1) the spin projection is crucial in achieving good approximation of the full shell model calculation; (2) the intrinsic shapes of the VAP wave functions with spin projection are always triaxial, while the Hartree-Fock-Bogoliubov methods likely provide axial intrinsic shapes. Finally, our analysis suggests that one may not be possible to associate an intrinsic shape to an exact shell model wave function.

  15. Oscillator strengths of some Ba lines - A treatment including core-valence correlation and relativistic effects

    NASA Technical Reports Server (NTRS)

    Bauschlicher, C. W., Jr.; Jaffe, R. L.; Langhoff, S. R.; Partridge, H.; Mascarello, F. G.

    1985-01-01

    Theoretical calculations of selected excitation energies and oscillator strengths for Ba are presented that overcome the difficulties of previous theoretical treatments. A relativistic effective-core potential treatment is used to account for the relativistic core contraction, but the outermost ten electrons are treated explicitly. Core-valence correlation can be included in this procedure in a rigorous and systematic way through a configuration-interaction calculation. Insight is gained into the importance of relativistic effects by repeating many of the calculations using an all-electron nonrelativistic treatment employing an extended Slater basis set. It is found that the intensity of the intercombination line 3P1-1S0 is accurately determined by accounting for the deviation from LS coupling through spin-orbit mixing with the 1P1 state, and that deviations from the Lande interval rule provide an accurate measure of the degree of mixing.

  16. 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.

  17. Transmission line model for strained quantum well lasers including carrier transport and carrier heating effects.

    PubMed

    Xia, Mingjun; Ghafouri-Shiraz, H

    2016-03-01

    This paper reports a new model for strained quantum well lasers, which are based on the quantum well transmission line modeling method where effects of both carrier transport and carrier heating have been included. We have applied this new model and studied the effect of carrier transport on the output waveform of a strained quantum well laser both in time and frequency domains. It has been found that the carrier transport increases the turn-on, turn-off delay times and damping of the quantum well laser transient response. Also, analysis in the frequency domain indicates that the carrier transport causes the output spectrum of the quantum well laser in steady state to exhibit a redshift which has a narrower bandwidth and lower magnitude. The simulation results of turning-on transients obtained by the proposed model are compared with those obtained by the rate equation laser model. The new model has also been used to study the effects of pump current spikes on the laser output waveforms properties, and it was found that the presence of current spikes causes (i) wavelength blueshift, (ii) larger bandwidth, and (iii) reduces the magnitude and decreases the side-lobe suppression ratio of the laser output spectrum. Analysis in both frequency and time domains confirms that the new proposed model can accurately predict the temporal and spectral behaviors of strained quantum well lasers.

  18. Do triaxial supramassive compact stars exist?

    NASA Astrophysics Data System (ADS)

    Uryū, Kōji; Tsokaros, Antonios; Baiotti, Luca; Galeazzi, Filippo; Sugiyama, Noriyuki; Taniguchi, Keisuke; Yoshida, Shin'ichirou

    2016-11-01

    We study quasiequilibrium solutions of triaxially deformed rotating compact stars—a generalization of Jacobi ellipsoids under relativistic gravity and compressible equations of state (EOSs). For relatively stiff (piecewise) polytropic EOSs, we find supramassive triaxial solutions whose masses exceed the maximum mass of the spherical solution, but are always lower than those of axisymmetric equilibriums. The difference in the maximum masses of triaxial and axisymmetric solutions depends sensitively on the EOSs. If the difference turns out to be only about 10%, it will be strong evidence that the EOS of high density matter becomes substantially softer in the core of neutron stars. This finding opens a novel way to probe phase transitions of high density nuclear matter using detections of gravitational waves from new born neutron stars or magnetars under fallback accretion.

  19. Numerical simulation of overvoltage caused by lightning on aerial power lines, including the corona effect

    NASA Astrophysics Data System (ADS)

    Ahcene, Z.; Bernard, G.

    1981-12-01

    A corona effect analog model is studied, and the influence of surges due to lightning on power lines is discussed. The effect of a lightning strike on lines with and without guard cables was simulated. Results show that the surge is very strongly damped as it travels away from the strike point. The corona effect lengthens front times and dampens the high frequency components of the propagated waves.

  20. 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

    2016-08-05

    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.

  1. 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.

  2. Line shape of amplitude or frequency-modulated spectral profiles including resonator distortions.

    PubMed

    Suter, Martin; Quack, Martin

    2015-05-10

    We report experiments and an improved method of analysis for any harmonics of frequency-modulated spectral line shapes allowing for very precise determinations of the resonance frequency of single absorption lines for gigahertz spectroscopy in the gas phase. Resonator perturbations are implemented into the formalism of modulation spectroscopy by means of a full complex transmission function being able to model the asymmetrically distorted absorption line shapes for arbitrary modulation depths, modulation frequencies, and resonator reflectivities. Exact equations of the in-phase and the quadrature modulation signal, taking into account a full resonator transmission function, are simultaneously adjusted to two-channel lock-in measurements performed in the gigahertz regime to obtain the spectral line position. The determination of the absorption line position of the rotational transition J' = 7 ← J" = 6 of (16)O(12)C(32)S in the vibrational ground state is investigated while changing the resonator distortions. The results are subjected to the approach proposed here and compared to standard methods known from the literature.

  3. Parametric design of tri-axial nested Helmholtz coils.

    PubMed

    Abbott, Jake J

    2015-05-01

    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.

  4. 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.

  5. Wobbling geometry in a simple triaxial rotor

    NASA Astrophysics Data System (ADS)

    Shi, Wen-Xian; Chen, Qi-Bo

    2015-05-01

    The spectroscopic properties and angular momentum geometry of the wobbling motion of a simple triaxial rotor are investigated within the triaxial rotor model. The obtained exact solutions of energy spectra and reduced quadrupole transition probabilities are compared to the approximate analytic solutions from the harmonic approximation formula and Holstein-Primakoff formula. It is found that the low lying wobbling bands can be well described by the analytic formulae. The evolution of the angular momentum geometry as well as the K-distribution with respect to the rotation and the wobbling phonon excitation are studied in detail. It is demonstrated that with the increase of the wobbling phonon number, the triaxial rotor changes its wobbling motions along the axis with the largest moment of inertia to the axis with the smallest moment of inertia. In this process, a specific evolutionary track that can be used to depict the motion of a triaxial rotating nucleus is proposed. Supported by President's Undergraduate Research Fellowship (PURF), Peking University, Major State 973 Program of China (2013CB834400), National Natural Science Foundation of China (11175002, 11335002, 11375015, 11345004, 11461141002), National Fund for Fostering Talents of Basic Science (NFFTBS) (J1103206) and Research Fund for the Doctoral Program of Higher Education (20110001110087)

  6. 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.

  7. Synchrophasors-Assisted IPII-Based Intelligent Relaying for Transmission Lines Including UPFC

    NASA Astrophysics Data System (ADS)

    Jena, Manas Kumar; Samantaray, S. R.

    2015-02-01

    This paper proposes a synchrophasors-assisted intelligent relaying scheme for transmission lines compensated by Unified Power Flow Controller (UPFC). The algorithm uses a new relaying signal termed as imaginary part of integrated impedance (IPII). The synchronized phasor measurements at both ends of the transmission line are used to extract voltage and current phasors from instantaneous voltage and current signals. The voltage and current phasors are utilized to derive IPII of each phase. Further, IPII of each phase is used as input to a data-mining model termed as decision tree (DT) which provides the final relaying decision. The proposed algorithm is validated on real-time digital simulator (RTDS) platform, and the results obtained indicate that the proposed scheme is both dependable and secure in protecting transmission system compensated by UPFC.

  8. Termination for a superconducting power transmission line including a horizontal cryogenic bushing

    DOEpatents

    Minati, Kurt F.; Morgan, Gerry H.; McNerney, Andrew J.; Schauer, Felix

    1984-01-01

    A termination for a superconducting power transmission line is disclosed which is comprised of a standard air entrance insulated vertical bushing with an elbow, a horizontal cryogenic bushing linking the pressurized cryogenic cable environment to the ambient temperature bushing and a stress cone which terminates the cable outer shield and transforms the large radial voltage gradient in the cable dielectric into a much lower radial voltage gradient in the high density helium coolant at the cold end of the cryogenic bushing.

  9. Frequency tuning of the optical delay in cesium D{sub 2} line including hyperfine structure

    SciTech Connect

    Anderson, Monte D.; Perram, Glen P.

    2010-03-15

    The frequency dependence of optical delays in both the wings and core of the cesium 6 {sup 2}S{sub 1/2}-6 {sup 2}P{sub 3/2} transition have been observed and modeled with a Voigt line shape convolved with the six hyperfine components. Tunable delays of 0-37 ns are achieved by tuning the laser frequency through resonance at various vapor pressures of 0.15-5.28 mTorr.

  10. The 4850 cm^{-1} Spectral Region of CO_2: Constrained Multispectrum Nonlinear Least Squares Fitting Including Line Mixing, Speed Dependent Line Profiles and Fermi Resonance

    NASA Astrophysics Data System (ADS)

    Benner, D. Chris; Devi, V. Malathy; Nugent, Emily; Brown, Linda R.; Miller, Charles E.; Toth, Robert A.; Sung, Keeyoon

    2009-06-01

    Room temperature spectra of carbon dioxide were obtained with the Fourier transform spectrometers at the National Solar Observatory's McMath-Pierce telescope and at the Jet Propulsion Laboratory. The multispectrum nonlinear least squares fitting technique is being used to derive accurate spectral line parameters for the strongest CO_2 bands in the 4700-4930 cm^{-1} spectral region. Positions of the spectral lines were constrained to their quantum mechanical relationships, and the rovibrational constants were derived directly from the fit. Similarly, the intensities of the lines within each of the rovibrational bands were constrained to their quantum mechanical relationships, and the band strength and Herman-Wallis coefficients were derived directly from the fit. These constraints even include a pair of interacting bands with the interaction coefficient derived directly using both the positions and intensities of the spectral lines. Room temperature self and air Lorentz halfwidth and pressure induced line shift coefficients are measured for most lines. Constraints upon the positions improve measurement of pressure-induced shifts, and constraints on the intensities improve the measurement of the Lorentz halfwidths. Line mixing and speed dependent line shapes are also required and characterized. D. Chris Benner, C.P. Rinsland, V. Malathy Devi, M.A.H. Smith, and D. Atkins, J. Quant. Spectrosc. Radiat. Transfer 53, 705-721 (1995)

  11. Microregion model of a contact line including evaporation, kinetics and slip

    NASA Astrophysics Data System (ADS)

    Anderson, Daniel; Janecek, Vladislav

    2016-11-01

    We consider the evaporation of a liquid on a uniformly heated solid substrate. In the framework of lubrication theory we consider hydrodynamics, heat conduction, phase change, evaporation kinetics, and slip. Our model focuses only on the contact line 'inner' region which allows us to quantify the impact of evaporation on the apparent contact angle and microregion heat transfer. The linearized problem with respect to the substrate overheating is solved analytically. The analytical solutions are compared with full numerical solutions and to predictions of Hocking.

  12. Chiral Bands for Quasi-Proton and Quasi-Neutron Coupling with a Triaxial Rotor

    NASA Astrophysics Data System (ADS)

    Qi, B.; Zhang, S. Q.; Wang, S. Y.; Meng, J.

    2008-04-01

    A particle rotor model (PRM) with a quasi-proton and a quasi-neutron coupled with a triaxial rotor is developed and applied to study chiral doublet bands with configurations of an h11/2 proton and an h11/2 quasi-neutron. With pairing treated by the BCS approximation, the present quasi-particle PRM is aimed at simulating one proton and many neutron holes coupled with a triaxial rotor. It is found that aplanar rotation or equivalently chiral geometry exists beyond the usual one proton and one neutron hole coupled with a triaxial rotor. After including the pairing correlation, the model describes the candidate chiral bands in 126Cs successfully, which supports the interpretation of chirality geometry.

  13. Inertial modes in a rotating triaxial ellipsoid.

    PubMed

    Vantieghem, S

    2014-08-08

    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.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. Geodetic altitude to a triaxial ellipsoidal planet

    NASA Technical Reports Server (NTRS)

    Tang, Charles C. H.

    1988-01-01

    An efficient theoretical model for determining geodetic altitudes with better than millimeter accuracy is proposed, with application to the TOPEX/Poseidon project. The triaxial ellipsoidal subsurface point of a satellite is used as the initial trial solution to achieve an efficient and simple iterative solution. It is found that the second-iteration solution is exact to an accuracy of at least 10 to the -9th km.

  19. Geodetic altitude to a triaxial ellipsoidal planet

    NASA Astrophysics Data System (ADS)

    Tang, Charles C. H.

    1988-09-01

    An efficient theoretical model for determining geodetic altitudes with better than millimeter accuracy is proposed, with application to the TOPEX/Poseidon project. The triaxial ellipsoidal subsurface point of a satellite is used as the initial trial solution to achieve an efficient and simple iterative solution. It is found that the second-iteration solution is exact to an accuracy of at least 10 to the -9th km.

  20. A Hybrid Model for the Spectra of Neutron Star Accretion Columns Including Comptonization and Cyclotron Lines

    NASA Astrophysics Data System (ADS)

    Schwarm, Fritz-Walter; Schönherr, G.; Becker, P. A.; Wolff, M. T.; Wilms, J.; Ferrigno, C.; West, B.

    2013-04-01

    A physical model for the radiation emitted from accretion columns of neutron stars with magnetic fields on the order of 1012 G has to reflect the large-scale dynamical structure of the inflowing matter as well as the quantum mechanical scattering processes leading to the formation of cyclotron resonant scattering features (CRSFs). Becker & Wolff (B&W) developed an analytic model for the broadband continuum while the CRSFs have been investigated by Schönherr & Schwarm (S&S). While both models describe the separate trends seen in observational data very well, a fully self-consistent fitting approach to determine the physical parameters (e.g., accretion rate, magnetic field strength) of the accretion column in accreting X-ray pulsars requires accounting for both processes in one unified model. We present our first approach towards such an unified hybrid model covering both the macro- and the microphysics of the accreting plasma. We assume a cylinder symmetrical dual layer structure of the accretion column. The inner layer reflects the dynamical structure described by the B&W model while the optical thin outer layer acts as a CRSF forming region similar to a photosphere. We adopt the parameters from a fit of the B&W model to Her X-1 and calculate the emergent radiation as well as the dynamical properties such as bulk velocity within the core of the accretion column. Radiation escaping the optical thick core region is further altered by the outer shell, a thin layer with an optical depth on the order of 10-4-10-2 Thomson optical depth, adding cyclotron lines by processing it through the S&S model. This hybrid model is only a first step towards an unified model for accreting neutron stars with strong magnetic fields. In the future we will investigate the insertion of a third layer in the middle as a transition region, parameter boundaries, and also incorporate general relativity with the ultimate goal to use this new tool to model phase-resolved spectroscopy of

  1. On parameterization of spectral line profiles including the speed-dependence in the case of gas mixtures

    NASA Astrophysics Data System (ADS)

    Kochanov, V. P.

    2017-03-01

    The physically grounded parameterization of a line profile including the speed-dependence was performed. It was shown that two actual parameters of the quadratic speed-dependence appear in gas mixtures instead of a single parameter in a pure gas. One of the parameters is associated with hard elastic velocity-changing collisions; the second is connected with the other sorts of collisions. For comparable concentrations of gas species, they may differ by 50% and depend nonlinearly on partial gas pressures. The dimensionless line narrowing parameter also reveals nonlinear pressure-dependence. The computational expressions for the line profile including all main physical mechanisms of its forming in conditions of gas mixtures are derived.

  2. Lined sampling vessel including a filter to separate solids from liquids on exit

    DOEpatents

    Shurtliff, Rodney M.; Klingler, Kerry M.; Turner, Terry D.

    2001-01-01

    A filtering apparatus has an open canister with an inlet port. A canister lid is provided which includes an outlet port for the passage of fluids from the canister. Liners are also provided which are shaped to fit the interiors of the canister and the lid, with at least the canister liner preferably being flexible. The sample to be filtered is positioned inside the canister liner, with the lid and lid liner being put in place thereafter. A filter element is located between the sample and the outlet port. Seals are formed between the canister liner and lid liner, and around the outlet port to prevent fluid leakage. A pressure differential is created between the canister and the canister liner so that the fluid in the sample is ejected from the outlet port and the canister liner collapses around the retained solids.

  3. Line parameters including temperature dependences of air- and self-broadened line shapes of 12C16O2: 2.06-μm region

    NASA Astrophysics Data System (ADS)

    Benner, D. Chris; Devi, V. Malathy; Sung, Keeyoon; Brown, Linda R.; Miller, Charles E.; Payne, Vivienne H.; Drouin, Brian J.; Yu, Shanshan; Crawford, Timothy J.; Mantz, Arlan W.; Smith, Mary Ann H.; Gamache, Robert R.

    2016-08-01

    This study reports the results from analyzing a number of high resolution, high signal-to-noise ratio (S/N) spectra in the 2.06-μm spectral region for pure CO2 and mixtures of CO2 in dry air. A multispectrum nonlinear least squares curve fitting technique has been used to retrieve the various spectral line parameters. The dataset includes 27 spectra: ten pure CO2, two 99% 13C-enriched CO2 and fifteen spectra of mixtures of 12C-enriched CO2 in dry air. The spectra were recorded at various gas sample temperatures between 170 and 297 K. The absorption path lengths range from 0.347 to 49 m. The sample pressures for the pure CO2 spectra varied from 1.1 to 594 Torr; for the two 13CO2 spectra the pressures were ∼10 and 146 Torr. For the air-broadened spectra, the pressures of the gas mixtures varied between 200 and 711 Torr with CO2 volume mixing ratios ranging from 0.014% to 0.203%. The multispectrum fitting technique was applied to fit simultaneously all these spectra to retrieve consistent set of line positions, intensities, and line shape parameters including their temperature dependences; for this, the Voigt line shape was modified to include line mixing (via the relaxation matrix formalism) and quadratic speed dependence. The new results are compared to select published values, including recent ab initio calculations. These results are required to retrieve the column averaged dry air mole fraction (XCO2) from space-based observations, such as the Orbiting Carbon Observatory-2 (OCO-2) satellite mission that NASA launched in July 2014.

  4. 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.

  5. 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.

  6. 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.

  7. Impact of cell lines included in enterovirus isolation protocol on perception of nonpolio enterovirus species C diversity.

    PubMed

    Adeniji, Johnson Adekunle; Faleye, Temitope Oluwasegun Cephas

    2014-10-01

    There has been under-reporting of nonpolio enterovirus species Cs (NPESCs) in Nigeria despite the fact that most isolates recovered from the Nigerian vaccine derived poliovirus serotype 2 (VDPV2) outbreak were recombinants with nonstructural region of NPESC origin. It has been suggested that cell lines included in enterovirus isolation protocols might account for this phenomenon and this study examined this suggestion. Fifteen environmental samples concentrated previously and analysed using L20B and RD cell lines as part of the poliovirus environmental surveillance (ES) program in Nigeria were randomly selected and inoculated into two cell lines (MCF-7 and LLC-MK2). Isolates were identified as enteroviruses and species C members using different RT-PCR assays, culture in L20B cell line and sequencing of partial VP1. Forty-eight (48) isolates were recovered from the 15 samples, 47 (97.9%) of which were enteroviruses. Of the enteroviruses, 32 (68.1%) belonged to enterovirus species C (EC) of which 19 (40.4%) were polioviruses and 13 (27.7%) were NPESC members. All 13 NPESC isolates were recovered on MCF-7. Results of the study show that NPESCs are circulating in Nigeria and their under-reporting was due to the combination of cell lines used for enterovirus isolation in previous reports.

  8. Comparison of first-line chemotherapy including escalated BEACOPP versus chemotherapy including ABVD for people with early unfavourable or advanced stage Hodgkin lymphoma.

    PubMed

    Skoetz, Nicole; Will, Andrea; Monsef, Ina; Brillant, Corinne; Engert, Andreas; von Tresckow, Bastian

    2017-05-25

    There are two different international standards for the treatment of early unfavourable and advanced stage Hodgkin lymphoma (HL): chemotherapy with escalated BEACOPP (bleomycin/etoposide/doxorubicin/cyclophosphamide/vincristine/procarbazine/prednisone) regimen and chemotherapy with ABVD (doxorubicin/bleomycin/vinblastine/dacarbazine) regimen. To determine the advantages and disadvantages of chemotherapy including escalated BEACOPP compared to chemotherapy including ABVD in the treatment of early unfavourable or advanced stage HL as first-line treatment. We searched for randomised controlled trials in MEDLINE, CENTRAL and conference proceedings (January 1985 to July 2013 and for the update to March 2017) and Embase (1985 to November 2008). Moreover we searched trial registries (March 2017; www.controlled-trials.com, www.clinicaltrialsregister.eu/ctr-search/search, clinicaltrials.gov, www.eortc.be, www.ghsg.org, www.ctc.usyd.edu.au, www.trialscentral.org/index.html) SELECTION CRITERIA: We included randomised controlled trials examining chemotherapy including at least two cycles of escalated BEACOPP regimens compared with chemotherapy including at least four cycles of ABVD regimens as first-line treatment for patients with early unfavourable stage or advanced stage HL. The effect measures we used were hazard ratios (HRs) for overall survival (OS), progression-free survival (PFS) and freedom from first progression.We used risk ratios (RRs) relative risks to analyse harms: treatment-related mortality, secondary malignancies (including myeloid dysplastic syndrome (MDS) or acute myeloid leukaemia (AML)), infertility and adverse events.Quality of life was not reported in any trial, therefore not analysed. Two review authors independently extracted data and assessed quality of trials. We screened 1796 records and identified five eligible trials in total i.e. one trial could be added on the previous review. These trials included only adults (16 to 65 years of age). We

  9. The widely used Nicotiana benthamiana 16c line has an unusual T-DNA integration pattern including a transposon sequence.

    PubMed

    Philips, Joshua G; Naim, Fatima; Lorenc, Michał T; Dudley, Kevin J; Hellens, Roger P; Waterhouse, Peter M

    2017-01-01

    Nicotiana benthamiana is employed around the world for many types of research and one transgenic line has been used more extensively than any other. This line, 16c, expresses the Aequorea victoria green fluorescent protein (GFP), highly and constitutively, and has been a major resource for visualising the mobility and actions of small RNAs. Insights into the mechanisms studied at a molecular level in N. benthamiana 16c are likely to be deeper and more accurate with a greater knowledge of the GFP gene integration site. Therefore, using next generation sequencing, genome mapping and local alignment, we identified the location and characteristics of the integrated T-DNA. As suggested from previous molecular hybridisation and inheritance data, the transgenic line contains a single GFP-expressing locus. However, the GFP coding sequence differs from that originally reported. Furthermore, a 3.2 kb portion of a transposon, appears to have co-integrated with the T-DNA. The location of the integration mapped to a region of the genome represented by Nbv0.5scaffold4905 in the www.benthgenome.com assembly, and with less integrity to Niben101Scf03641 in the www.solgenomics.net assembly. The transposon is not endogenous to laboratory strains of N. benthamiana or Agrobacterium tumefaciens strain GV3101 (MP90), which was reportedly used in the generation of line 16c. However, it is present in the popular LBA4404 strain. The integrated transposon sequence includes its 5' terminal repeat and a transposase gene, and is immediately adjacent to the GFP gene. This unexpected genetic arrangement may contribute to the characteristics that have made the 16c line such a popular research tool and alerts researchers, taking transgenic plants to commercial release, to be aware of this genomic hitchhiker.

  10. The widely used Nicotiana benthamiana 16c line has an unusual T-DNA integration pattern including a transposon sequence

    PubMed Central

    Lorenc, Michał T.; Dudley, Kevin J.; Hellens, Roger P.

    2017-01-01

    Nicotiana benthamiana is employed around the world for many types of research and one transgenic line has been used more extensively than any other. This line, 16c, expresses the Aequorea victoria green fluorescent protein (GFP), highly and constitutively, and has been a major resource for visualising the mobility and actions of small RNAs. Insights into the mechanisms studied at a molecular level in N. benthamiana 16c are likely to be deeper and more accurate with a greater knowledge of the GFP gene integration site. Therefore, using next generation sequencing, genome mapping and local alignment, we identified the location and characteristics of the integrated T-DNA. As suggested from previous molecular hybridisation and inheritance data, the transgenic line contains a single GFP-expressing locus. However, the GFP coding sequence differs from that originally reported. Furthermore, a 3.2 kb portion of a transposon, appears to have co-integrated with the T-DNA. The location of the integration mapped to a region of the genome represented by Nbv0.5scaffold4905 in the www.benthgenome.com assembly, and with less integrity to Niben101Scf03641 in the www.solgenomics.net assembly. The transposon is not endogenous to laboratory strains of N. benthamiana or Agrobacterium tumefaciens strain GV3101 (MP90), which was reportedly used in the generation of line 16c. However, it is present in the popular LBA4404 strain. The integrated transposon sequence includes its 5’ terminal repeat and a transposase gene, and is immediately adjacent to the GFP gene. This unexpected genetic arrangement may contribute to the characteristics that have made the 16c line such a popular research tool and alerts researchers, taking transgenic plants to commercial release, to be aware of this genomic hitchhiker. PMID:28231340

  11. Line parameters including temperature dependences of self- and air-broadened line shapes of 12C16O2: 1.6-μm region

    NASA Astrophysics Data System (ADS)

    Devi, V. Malathy; Benner, D. Chris; Sung, Keeyoon; Brown, Linda R.; Crawford, Timothy J.; Miller, Charles E.; Drouin, Brian J.; Payne, Vivienne H.; Yu, Shanshan; Smith, Mary Ann H.; Mantz, Arlan W.; Gamache, Robert R.

    2016-07-01

    Pressure-broadened line shapes in the 30013←00001 (ν1+4 ν20 +ν3) band of 12C16O2 at 6228 cm-1 are reanalyzed using new spectra recorded with sample temperatures down to 170 K. High resolution, high signal-to-noise (S/N) laboratory measurements of line shapes (Lorentz air- and self-broadened half-width coefficients, pressure-shift coefficients and off-diagonal relaxation matrix element coefficients) as a function of gas sample temperatures for various pressures and volume mixing ratios are presented. The spectra were recorded using two different Fourier transform spectrometers (FTS): (1) the McMath-Pierce FTS located at the National Solar Observatory on Kitt Peak, Arizona (and reported in Devi et al., J Mol Spectrosc 2007;245:52-80) and, (2) the Bruker IFS-125HR FTS at the Jet Propulsion Laboratory in Pasadena, California. The 19 spectra taken at Kitt Peak were all recorded near room temperature while the 27 Bruker spectra were acquired both at room temperature and colder temperatures (170-296 K). Various spectral resolutions (0.004-0.011 cm-1), absorption path lengths (2.46-121 m) and CO2 samples (natural and 12C-enriched) were included in the dataset. To maximize the accuracies of the various retrieved line parameters, a multispectrum nonlinear least squares spectrum fitting software program was used to adjust the ro-vibrational constants (G,B,D etc.) and intensity parameters (including Herman-Wallis terms) instead of directly measuring the individual line positions and intensities. To minimize systematic residuals, line mixing (via off-diagonal relaxation matrix elements) and quadratic speed dependence parameters were included in the analysis. Contributions from other weakly absorbing bands: the 30013←00001 and 30012←00001 bands of 13C16O2, the 30013←00001 band of 12C16O18O, hot bands 31113←01101 and 32212←02201 of 12C16O2, as well as the 40013←10001 and the 40014←10002 bands of 12C16O2, present within the fitted interval were also measured

  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. Acquired, Idiopathic, Patterned Facial Pigmentation (AIPFP) Including Periorbital Pigmentation and Pigmentary Demarcation Lines on Face Follows the Lines of Blaschko on Face

    PubMed Central

    Sarma, Nilendu; Chakraborty, Sayantani; Bhattacharya, Sneha Ranjan

    2014-01-01

    Background: Acquired, non-nevoid, apparently idiopathic facial pigmentation are distributed over some specific locations like periorbital area, zygomatic area, malar area, root of nose, perioral and mandibular area. Periorbital pigmentation is the most well known entity in this group. These are bilaterally distributed homogenously diffuse gray to dark gray or slate-gray colored patches showing progressive intensification of pigmentation. These are often considered as physiologic or constitutional pigmentation. Some portions of the margins of these patches were described previously as pigmentary demarcation line (PDL- F, G, H). Aim: To analyze the distributional patterns of acquired, apparently idiopathic facial pigmentations and to evaluate the etiologic aspects of these conditions. Materials and Methods: Spatial patterns, distribution, and orientation were analyzed among 187 individuals with idiopathic non-nevoid, facial pigmentation. Observed patterns were compared with various pigmentary nevi and Blaschko's lines on face. Results: It was found that most of the idiopathic facial pigmentary alterations including periorbital pigmentation and PDL on face had specific patterned distribution that had high similarity to that of the pigmentary nevi and Blaschko's lines on face. Conclusion: It is hypothesized here that phenotypic expression of acquired patterned pigmentation (AIFPFP) is due to genetically determined increased pigmentary functional activity to various known and unknown yet natural factors like UV rays and aging. Mosaicism was a definite possibility. We also consider that the patterns actually reflected the normal patterns of embryological human pigmentation on face. PMID:24470659

  14. 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.

  15. 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.

  16. Robust adaptive control of MEMS triaxial gyroscope using fuzzy compensator.

    PubMed

    Fei, Juntao; Zhou, Jian

    2012-12-01

    In this paper, a robust adaptive control strategy using a fuzzy compensator for MEMS triaxial gyroscope, which has system nonlinearities, including model uncertainties and external disturbances, is proposed. A fuzzy logic controller that could compensate for the model uncertainties and external disturbances is incorporated into the adaptive control scheme in the Lyapunov framework. The proposed adaptive fuzzy controller can guarantee the convergence and asymptotical stability of the closed-loop system. The proposed adaptive fuzzy control strategy does not depend on accurate mathematical models, which simplifies the design procedure. The innovative development of intelligent control methods incorporated with conventional control for the MEMS gyroscope is derived with the strict theoretical proof of the Lyapunov stability. Numerical simulations are investigated to verify the effectiveness of the proposed adaptive fuzzy control scheme and demonstrate the satisfactory tracking performance and robustness against model uncertainties and external disturbances compared with conventional adaptive control method.

  17. Measurement of specimen dimensions and dynamic pressure in dynamic triaxial experiments

    NASA Astrophysics Data System (ADS)

    Kabir, Md. E.; Chen, Weinong W.

    2009-12-01

    Novel experimental techniques are developed to measure the rapid changes in specimen dimensions during dynamic triaxial experiments. A capacitance gage is designed and constructed to measure the diameter change of the specimen inside the pressure chamber at both low and high rates. The length change is determined by a linear variable differential transformer at low rates and by Kolsky bar signals at high rates. The Kolsky bar also measures the dynamic axial stress in the specimen during the high-rate phase of an experiment. A line pressure gage records the hydrostatic pressure in the chamber. The dynamic pressure variation in the chamber during axial impact loading is detected by a manganin gage placed inside the chamber. The feasibility of this new experimental setup is demonstrated by dynamic triaxial experiments on a fine dry sand.

  18. Measurement of specimen dimensions and dynamic pressure in dynamic triaxial experiments.

    PubMed

    Kabir, Md E; Chen, Weinong W

    2009-12-01

    Novel experimental techniques are developed to measure the rapid changes in specimen dimensions during dynamic triaxial experiments. A capacitance gage is designed and constructed to measure the diameter change of the specimen inside the pressure chamber at both low and high rates. The length change is determined by a linear variable differential transformer at low rates and by Kolsky bar signals at high rates. The Kolsky bar also measures the dynamic axial stress in the specimen during the high-rate phase of an experiment. A line pressure gage records the hydrostatic pressure in the chamber. The dynamic pressure variation in the chamber during axial impact loading is detected by a manganin gage placed inside the chamber. The feasibility of this new experimental setup is demonstrated by dynamic triaxial experiments on a fine dry sand.

  19. Measurement of specimen dimensions and dynamic pressure in dynamic triaxial experiments

    SciTech Connect

    Kabir, Md. E.

    2009-12-15

    Novel experimental techniques are developed to measure the rapid changes in specimen dimensions during dynamic triaxial experiments. A capacitance gage is designed and constructed to measure the diameter change of the specimen inside the pressure chamber at both low and high rates. The length change is determined by a linear variable differential transformer at low rates and by Kolsky bar signals at high rates. The Kolsky bar also measures the dynamic axial stress in the specimen during the high-rate phase of an experiment. A line pressure gage records the hydrostatic pressure in the chamber. The dynamic pressure variation in the chamber during axial impact loading is detected by a manganin gage placed inside the chamber. The feasibility of this new experimental setup is demonstrated by dynamic triaxial experiments on a fine dry sand.

  20. Stellar Bar Evolution in Cuspy and Flat-cored Triaxial CDM Halos

    NASA Astrophysics Data System (ADS)

    Berentzen, Ingo; Shlosman, Isaac; Jogee, Shardha

    2006-02-01

    We analyze the formation and evolution of stellar bars in galactic disks embedded in mildly triaxial cold dark matter (CDM) halos that have density distributions ranging from large flat cores to cuspy profiles. We have applied tailored numerical simulations of analytical and live halos that include the feedback from disk/bar system onto the halo in order to test and extend earlier work by El-Zant and Shlosman. The latter employed the method of Liapunov exponents to analyze the fate of bars in analytical asymmetric halos. We find the following: (1) The bar growth is very similar in all rigid axisymmetric and triaxial halos. (2) Bars in live models experience vertical buckling instability and the formation of a pseudobulge with a boxy/peanut shape, while bars in rigid halos do not buckle. (3) In live axisymmetric halos, the bar strength varies by a factor of <~2, in growth or decay, during the secular evolution following the buckling. The bar pattern speed evolution (i.e., deceleration) anticorrelates with the halo core size. In such halos, the bar strength is larger for smaller disk-to-halo mass ratios (D/H) within disk radii, the bar size correlates with the halo core sizes, and the bar pattern speeds correlate with the halo central mass concentration. In contrast, bars embedded in live triaxial halos have a starkly different fate: they dissolve on a timescale of ~1.5-5 Gyr due to the onset of chaos over continuous zones, sometimes leaving behind a weak oval distortion. The onset of chaos is related to the halo triaxiality, the fast-rotating bar, and the halo cuspiness. Before the bar dissolves, the region outside it develops strong spiral structures, especially in the live triaxial halos. (4) More angular momentum is absorbed (fractionally) by the triaxial halos than in the axisymmetric models. The disk-halo angular momentum exchange is mediated by the lower resonances in the latter models. (5) Cuspy halos are more susceptible than flat-core halos to having their

  1. A Multispectrum Analysis Of Carbon Dioxide Bands In The 6280 To 6390 Cm-1 Including Line Mixing And Speed Dependence

    NASA Astrophysics Data System (ADS)

    Venkataraman, Malathy D.; Benner, D. C.; Brown, L. R.; Miller, C. E.; Toth, R. A.

    2006-09-01

    To support atmospheric remote sensing studies and obtain total column CO2 measurements with a precision of 0.3%, accurate values of ro-vibrational constants, vibrational band intensity and Herman-Wallis coefficients, self- and air-broadening and self- and air-induced pressure-shift coefficients have been measured for the CO2 bands in the 6280 to 6380 cm-1 spectral region from high-resolution (0.01-cm-1) long-path absorption spectra. In addition, line mixing coefficients in the P- and R-branches have also been determined using the off-diagonal relaxation matrix elements for both self- and air-broadening. A multispectrum nonlinear least squares fitting technique modified to include line mixing and speed-dependent line shape and the capability to constrain various spectral line parameters (e.g. positions and intensities) has been applied in the analysis to maximize the accuracy of the retrieved parameters. In addition to the 2201←0000 combination band, rotational constants and intensity parameters were measured for five additional bands that appeared in the same spectral region. The data used in this study were recorded at room temperature with the McMath-Pierce Fourier transform spectrometer (FTS) located at the National Solar Observatory on Kitt Peak. Where appropriate, present results are compared with previous measurements reported in the literature. Part of the research described in this paper was performed at the Jet Propulsion laboratory, California Institute of Technology under contracts and cooperative agreements with the National Aeronautics and Space Administration. The research conducted at the College of William and Mary is supported by the National Science Foundation under Grant No. ATM-0338475.

  2. 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.

  3. 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.

  4. 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.

  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. Effects of triaxial stressing on creep cavitation of grain boundaries

    SciTech Connect

    Sham, T.L.; Needleman, A.

    1983-01-01

    The authors investigate the influence of triaxial stressing on the growth of cavities on grain boundaries by the combined processes of plastic creep flow and grain boundary diffusion. The coupling arises from local accommodation of matter on the grain boundary near the cavity tip due to plastic creep deformability of the grains. This has the effect of shortening the diffusion path length on the grain boundary and increasing the cavity volumetric growth rate. An increase in triaxiality is found to accelerate the matter flux flowing from the cavity surfaces onto the grain boundaries and thus increase the cavity volumetric growth rate. This occurs at attainable levels of triaxiality. However, the enhancement in the triaxial stress state does not affect the effective diffusion path length very significantly. A simple formula for the volumetric growth rate of the cavity is suggested and it is found to give a good approximation to the numerically computed results.

  7. Effects of triaxial stressing on creep cavitation of grain boundaries

    SciTech Connect

    Sham, T.L.; Needleman, A.

    1982-09-01

    We investigate the influence of triaxial stressing on the growth of cavities on grain boundaries by the combined processes of plastic creep flow and grain boundary diffusion. The coupling arises from local accommodation of matter on the grain boundary near the cavity tip due to plastic creep deformability of the grains. This has the effect of shortening the diffusion path length on the grain boundary and increasing the cavity volumetric growth rate. An increase in triaxiality is found to accelerate the matter flux flowing from the cavity surfaces onto the grain boundaries and thus increase the cavity volumetric growth rate. This occurs at realizable levels of triaxiality. However, the enhancement in the triaxial stress state does not affect the effective diffusion path length very significantly. A simple formula for the volumetric growth rate of the cavity is suggested and it is found to give a good approximation to the numerically computed results.

  8. 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.

  9. Considerations on stress triaxiality variation for 2P armor steel

    NASA Astrophysics Data System (ADS)

    Zichil, V.; Coseru, A.; Nedeff, F.; Tomozei, C.

    2017-05-01

    Stress triaxiality is considered an invariant of stress, defined as the ratio of hydrostatic stress (hydrostatic pressure by other authors) and the equivalent stress (usually calculated using von Mises criterion). If the values of the main three stresses have comparable sizes, stress triaxiality can be also calculated using the first invariant of the stress tensor. Despite that the stress triaxiality is an invariant, the authors have determined experimentally and analytically its variation with the force at the tensile test, but also with the radius of notches caused in the specimen. 2P armor steel being used in lightweight armor, these notches occur after shocks with foreign objects. Furthermore, the authors have revealed the stress triaxiality variation function of the test type. The tests were performed on tensile specimens loaded for tensile test, pure torsion test, 25% tensile - 75% torsion test, 50% tensile - 50% torsion test, 75% tensile - 25% torsion test. The mathematical model used was designed by Xue.

  10. Crack damage evolution in rocks deformed under true triaxial loading

    NASA Astrophysics Data System (ADS)

    Browning, John; Meredith, Philip; Stuart, Chris; Healy, David; Harland, Sophie; Mitchell, Tom

    2017-04-01

    Microcrack damage in rocks evolves in response to differential loading. However, the vast majority of experimental studies investigate damage evolution using conventional triaxial stress states (σ1 > σ2 = σ3), whereas in nature the stress state is in general truly triaxial (σ1 > σ2 > σ3). We present a comparative study of conventional triaxial vs. true triaxial stress conditions using results from measurements made on cubic samples of sandstone deformed in three orthogonal directions with independently controlled stress paths. We have measured, simultaneously with stress and strain, the changes in ultrasonic compressional and shear wave velocities in the three principal directions, together with the bulk acoustic emission (AE) output. Changes in acoustic wave velocities are associated with both elastic closure and opening of pre-existing cracks, and the formation of new, highly oriented, cracks by inelastic processes. By contrast, AE is associated only with the inelastic growth of new cracks. Crack growth is shown to be a function of differential stress regardless of the mean stress. New cracks can form due to a decrease in the minimum principal stress, which reduces mean stress but increases the differential stress. We measure the AE, in both conventional triaxial and true triaxial tests and find an approximately fivefold decrease in the number of events in the true triaxial case. In essence, we create two end-member crack distributions; one displaying cylindrical transverse isotropy (conventional triaxial) and the other planar transverse isotropy (true triaxial). By measuring the acoustic wave velocities throughout each test we were able to model comparative crack densities and orientations. When taken together the AE data, the velocities and the crack density data indicate that the intermediate principal stress plays a key role in suppressing the total amount of crack growth and concentrates it in a single plane, but the size of individual cracks remains

  11. Mesoscale Phase Field Modeling of Glass Strengthening Under Triaxial Compression

    SciTech Connect

    Li, Yulan; Sun, Xin

    2015-09-28

    Recent hydraulic bomb and confined sleeve tests on transparent armor glass materials such as borosilicate glass and soda-lime glass showed that the glass strength was a function of confinement pressure. The measured stress-strain relation is not a straight line as most brittle materials behave under little or no confinement. Moreover, borosilicate glass exhibited a stronger compressive strength when compared to soda-lime glass, even though soda-lime has higher bulk and shear moduli as well as apparent yield strength. To better understand these experimental findings, a mesoscale phase field model is developed to simulate the nonlinear stress versus strain behaviors under confinement by considering heterogeneity formation under triaxial compression and the energy barrier of a micro shear banding event (referred to as pseudo-slip hereafter) in the amorphous glass. With calibrated modeling parameters, the simulation results demonstrate that the developed phase field model can quantitatively predict the pressure-dependent strength, and it can also explain the difference between the two types of glasses from the perspective of energy barrier associated with a pseudo-slip event.

  12. Triaxial AFM probes for noncontact trapping and manipulation.

    PubMed

    Brown, Keith A; Westervelt, Robert M

    2011-08-10

    We show that a triaxial atomic force microscopy probe creates a noncontact trap for a single particle in a fluid via negative dielectrophoresis. A zero in the electric field profile traps the particle above the probe surface, avoiding adhesion, and the repulsive region surrounding the zero pushes other particles away, preventing clustering. Triaxial probes are promising for three-dimensional assembly and for selective imaging of a particular property of a sample using interchangeable functionalized particles.

  13. True Triaxial Stresses and the Brittle Fracture of Rock

    NASA Astrophysics Data System (ADS)

    Haimson, Bezalel

    2006-06-01

    This paper reviews the efforts made in the last 100 years to characterize the effect of the intermediate principal stress σ 2 on brittle fracture of rocks, and on their strength criteria. The most common theories of failure in geomechanics, such as those of Coulomb, and Mohr, disregard σ 2 and are typically based on triaxial testing of cylindrical rock samples subjected to equal minimum and intermediate principal stresses (σ 3=σ 2). However, as early as 1915 Böker conducted conventional triaxial extension tests (σ 1=σ 2) on the same Carrara marble tested earlier in conventional triaxial compression by von Kármán that showed a different strength behavior. Efforts to incorporate the effect of σ 2 on rock strength continued in the second half of the last century through the work of Nadai, Drucker and Prager, Murrell, Handin, Wiebols and Cook, and others. In 1971 Mogi designed a high-capacity true triaxial testing machine, and was the first to obtain complete true triaxial strength criteria for several rocks based on experimental data. Following his pioneering work, several other laboratories developed equipment and conducted true triaxial tests revealing the extent of σ 2 effect on rock strength (e.g., Takahashi and Koide, Michelis, Smart, Wawersik). Testing equipment emulating Mogi's but considerably more compact was developed at the University of Wisconsin and used for true triaxial testing of some very strong crystalline rocks. Test results revealed three distinct compressive failure mechanisms, depending on loading mode and rock type: shear faulting resulting from extensile microcrack localization, multiple splitting along the σ 1 axis, and nondilatant shear failure. The true triaxial strength criterion for the KTB amphibolite derived from such tests was used in conjunction with logged breakout dimensions to estimate the maximum horizontal in situ stress in the KTB ultra deep scientific hole.

  14. An online recursive autocalibration of triaxial accelerometer.

    PubMed

    Lin Ye; Su, Steven W; Dong Lei; Nguyen, Hung T

    2016-08-01

    In this paper, we proposed a novel method for autocalibration of triaxial Micro-Electro-Mechanical systems (MEMS) accelerometer that does not require any sophisticated laboratory facilities. In particular, this method is an online calibration method which can be conveniently implemented with the accuracy of MEMS accelerometer being significantly improved. The procedure exploits the fact that the output vector of the accelerometer must match the local gravity in static state condition. To achieve online calibration, the model as well as the cost function are linearized at the beginning, and an online recursive method is then utilized to identify the unknown parameters and remove the bias caused by linearization. This online recursive method is based on damped recursive least square estimation (DRLS), which can significantly reduce the calculation complexity comparing to nonlinear optimization method. In addition, the unknown parameters can be solved in a short time and the estimated parameters can remain stable during calibration. Experimentally, this method was tested by comparing the output results before and after calibration in different condition. It showed that the output, after calibrated by the proposed method, is more accurate with respect to raw output using default factory parameters.

  15. 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.

  16. 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).

  17. Gravitational wave content and stability of uniformly, rotating, triaxial neutron stars in general relativity

    NASA Astrophysics Data System (ADS)

    Tsokaros, Antonios; Ruiz, Milton; Paschalidis, Vasileios; Shapiro, Stuart L.; Baiotti, Luca; Uryō, Kūji

    2017-06-01

    Targets for ground-based gravitational wave interferometers include continuous, quasiperiodic sources of gravitational radiation, such as isolated, spinning neutron stars. In this work, we perform evolution simulations of uniformly rotating, triaxially deformed stars, the compressible analogs in general relativity of incompressible, Newtonian Jacobi ellipsoids. We investigate their stability and gravitational wave emission. We employ five models, both normal and supramassive, and track their evolution with different grid setups and resolutions, as well as with two different evolution codes. We find that all models are dynamically stable and produce a strain that is approximately one-tenth the average value of a merging binary system. We track their secular evolution and find that all our stars evolve toward axisymmetry, maintaining their uniform rotation, rotational kinetic energy, and angular momentum profiles while losing their triaxiality.

  18. Enhanced Actuator Line Simulation of a Wind Turbine by including the Conservative Load at the Blade Tip

    NASA Astrophysics Data System (ADS)

    Herraez, Ivan; Micallef, Daniel; van Kuik, Gijs A. M.; Peinke, Joachim

    2015-11-01

    At the tip of wind turbine blades, the radial bound circulation is transformed into chordwise circulation just before being released as trailing vorticity, giving rise to the tip vortex. The force acting on the chordwise circulation contains a radial and a normal component with respect to the blade axis. This load does not contribute to the torque, so it is a conservative load. Due to this, it is disregarded in the engineering tools used for the design of wind turbines. However, as we demonstrated in a previous work, the conservative load might influence the trajectory of the tip vortex. In order to see how this affects the blade loads, in this research we perform large eddy simulations with an actuator line model where the conservative load has been included. The conservative load reduces the angle of attack in the tip region as a consequence of the modified tip vortex trajectory. This has a negative influence on the lift and the power output. We conclude that the accuracy of engineering design tools of wind turbines can be improved if the conservative load acting at the tip is considered.

  19. Anatomical Directional Dissimilarities in Tri-axial Swallowing Accelerometry Signals.

    PubMed

    Movahedi, Faezeh; Kurosu, Atsuko; Coyle, James L; Perera, Subashan; Sejdic, Ervin

    2017-05-01

    Swallowing accelerometry is a noninvasive approach currently under consideration as an instrumental screening test for swallowing difficulties, with most current studies focusing on the swallowing vibrations in the anterior-posterior (A-P) and superior-inferior (S-I) directions. However, the displacement of the hyolaryngeal structure during the act of swallowing in patients with dysphagia involves declination of the medial-lateral (M-L), which suggests that the swallowing vibrations in the M-L direction have the ability to reveal additional details about the swallowing function. With this motivation, we performed a broad comparison of the swallowing vibrations in all three anatomical directions. Tri-axial swallowing accelerometry signals were concurrently collected from 72 dysphagic patients undergoing videofluoroscopic evaluation of swallowing (mean age: 63.94 ± 12.58 years period). Participants swallowed one or more thickened liquids with different consistencies including thin-thick liquids, nectar-thick liquids, and pudding-thick liquids with either a comfortable self-selected volume from a cup or a controlled volume by the examiner from a 5-ml spoon. Swallows were grouped based on the viscosity of swallows and the participant's stroke history. Then, a comprehensive set of features was extracted in multiple signal domains from 881 swallows. The results highlighted inter-axis dissimilarities among tri-axial swallowing vibrations including the extent of variability in the amplitude of signals, the degree of predictability of signals, and the extent of disordered behavior of signals in time-frequency domain. First, the upward movement of the hyolaryngeal structure, representing the S-I signals, were actually more variable in amplitude and showed less predictable behavior than the sideways and forward movements, representing the A-P and M-L signals, during swallowing. Second, the S-I signals, which represent the upward movement of the hyolaryngeal structure

  20. Instability and Transition of Flow at, and Near, an Attachment-Line: Including Control by Surface Suction

    NASA Technical Reports Server (NTRS)

    Smith, A.; Poll, D. I. A.

    1998-01-01

    Experiments have been performed on an untapered, swept cylinder model in the Cranfield College of Aeronautics 8 ft x 6 ft low-speed wind tunnel to investigate the effect of surface transpiration on the process of relaminarization in the attachment-line boundary layer. Suction coefficients for complete suppression of turbulence were determined as a function of Reynolds number and spanwise distance. The effect of attachment-line suction on the spanwise propagation of gross disturbances emanating from the fuselage-wing junction region was also studied. Finally, the effect of blowing on a laminar attachment-line boundary layer was also considered and excellent agreement was achieved with previous studies.

  1. Triaxial models description of the low-lying properties in 192Os

    NASA Astrophysics Data System (ADS)

    Ning, T.; An, S. Y.; Li, X. X.; Yu, X. R.; Zhang, Y.

    2016-10-01

    Several typical triaxial models have been parallel addressed and applied to describe the energy values and B(E2) transitional rates in the ground band and the γ band for 192Os. It is shown that the different triaxial model presents different triaxial dynamics but each of them can only succeed to explain part of the spectral properties of this nucleus, which indicates that the triaxial shape of 192Os may be more complicated than that reflected by an ideal triaxial model. In addition, the staggering signature in experiments hints that γ-rigid triaxiality should be more or less involved in 192Os.

  2. 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.

  3. New estimates of the inertia tensor and rotation of the triaxial nonrigid Earth

    NASA Astrophysics Data System (ADS)

    Chen, Wei; Shen, Wenbin

    2010-12-01

    in good agreement with χeffsym and, further, show an increase of coherency with χobs especially in the low-frequency band. The obvious advantage of χeff in the low-frequency band with respect to χeffsym is the critical support of the present theory. However, still better performance of our theory can be expected if the models of the mantle anelasticity and oceanic dynamics were improved. Thus we conclude that the traditional Earth rotation theory should be revised and upgraded to include the effects of the Earth's triaxiality, the mantle anelasticity, and oceanic dynamics. The theory presented in this study might be more appropriate to describe the rotation of the triaxial Earth (or other triaxial celestial bodies such as Mars), though further studies are needed to incorporate the effects of the solid inner core and other possible influences.

  4. Triaxial orbit-based modelling of the Milky Way Nuclear Star Cluster

    NASA Astrophysics Data System (ADS)

    Feldmeier-Krause, A.; Zhu, L.; Neumayer, N.; van de Ven, G.; de Zeeuw, P. T.; Schödel, R.

    2017-04-01

    We construct triaxial dynamical models for the Milky Way nuclear star cluster using Schwarzschild's orbit superposition technique. We fit the stellar kinematic maps presented in Feldmeier et al. The models are used to constrain the supermassive black hole mass M•, dynamical mass-to-light ratio ϒ and the intrinsic shape of the cluster. Our best-fitting model has M• = (3.0^{+1.1}_{-1.3}) × 106 M⊙, ϒ = (0.90^{+0.76}_{-0.08}) M⊙/L⊙, 4.5μm and a compression of the cluster along the line of sight. Our results are in agreement with the direct measurement of the supermassive black hole mass using the motion of stars on Keplerian orbits. The mass-to-light ratio is consistent with stellar population studies of other galaxies in the mid-infrared. It is possible that we underestimate M• and overestimate the cluster's triaxiality due to observational effects. The spatially semiresolved kinematic data and extinction within the nuclear star cluster bias the observations to the near side of the cluster, and may appear as a compression of the nuclear star cluster along the line of sight. We derive a total dynamical mass for the Milky Way nuclear star cluster of MMWNSC = (2.1 ± 0.7) × 107 M⊙ within a sphere with radius r = 2 × reff = 8.4 pc. The best-fitting model is tangentially anisotropic in the central r = 0.5-2 pc of the nuclear star cluster, but close to isotropic at larger radii. Our triaxial models are able to recover complex kinematic substructures in the velocity map.

  5. Triaxial orbit-based modelling of the Milky Way Nuclear Star Cluster

    NASA Astrophysics Data System (ADS)

    Feldmeier-Krause, A.; Zhu, L.; Neumayer, N.; van de Ven, G.; de Zeeuw, P. T.; Schödel, R.

    2016-12-01

    We construct triaxial dynamical models for the Milky Way nuclear star cluster using Schwarzschild's orbit superposition technique. We fit the stellar kinematic maps presented in Feldmeier et al. (2014). The models are used to constrain the supermassive black hole mass M•, dynamical mass-to-light ratio Υ, and the intrinsic shape of the cluster. Our best-fitting model has M• = (3.0^{+1.1}_{-1.3}) × 106 M⊙, Υ = (0.90^{+0.76}_{-0.08}) M⊙/L⊙, 4.5μm, and a compression of the cluster along the line-of-sight. Our results are in agreement with the direct measurement of the supermassive black hole mass using the motion of stars on Keplerian orbits. The mass-to-light ratio is consistent with stellar population studies of other galaxies in the mid-infrared. It is possible that we underestimate M• and overestimate the cluster's triaxiality due to observational effects. The spatially semi-resolved kinematic data and extinction within the nuclear star cluster bias the observations to the near side of the cluster, and may appear as a compression of the nuclear star cluster along the line-of-sight. We derive a total dynamical mass for the Milky Way nuclear star cluster of MMWNSC = (2.1±0.7) × 107 M⊙ within a sphere with radius r = 2 × reff = 8.4 pc. The best-fitting model is tangentially anisotropic in the central r = 0.5-2 pc of the nuclear star cluster, but close to isotropic at larger radii. Our triaxial models are able to recover complex kinematic substructures in the velocity map.

  6. 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.

  7. 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.

  8. 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.

  9. Evolution of triaxial shapes at large isospin: Rh isotopes

    NASA Astrophysics Data System (ADS)

    Navin, A.; Rejmund, M.; Bhattacharyya, S.; Palit, R.; Bhat, G. H.; Sheikh, J. A.; Lemasson, A.; Bhattacharya, S.; Caamaño, M.; Clément, E.; Delaune, O.; Farget, F.; de France, G.; Jacquot, B.

    2017-04-01

    The rotational response as a function of neutron-proton asymmetry for the very neutron-rich isotopes of Rh (116-119Rh) has been obtained from the measurement of prompt γ rays from isotopically identified fragments, produced in fission reactions at energies around the Coulomb barrier. The measured energy ;signature; splitting of the yrast bands, when compared with the Triaxial Projected Shell Model (TPSM) calculations, shows the need for large, nearly constant, triaxial deformations. The present results are compared with global predictions for the existence of non axial shapes in the periodic table in the case of very neutron-rich nuclei Rh isotopes. The predicted trend of a second local maximum for a triaxial shape around N ∼ 74 is not found.

  10. Structure and symmetries of odd-odd triaxial nuclei

    NASA Astrophysics Data System (ADS)

    Palit, R.; Bhat, G. H.; Sheikh, J. A.

    2017-05-01

    Rotational spectra of odd-odd Rh and Ag isotopes are investigated with the primary motivation to search for the spontaneous chiral symmetry breaking phenomenon in these nuclei. The experimental results obtained on the degenerate dipole bands of some of these isotopes using a large array of gamma detectors are discussed and studied using the triaxial projected shell (TPSM) approach. It is shown that, first of all, to reproduce the odd-even staggering of the known yrast bands of these nuclei, large triaxial deformation is needed. This large triaxial deformation also gives rise to doublet band structures in many of these studied nuclei. The observed doublet bands in these isotopes are shown to be reproduced reasonably well by the TPSM calculations. Further, the TPSM calculations for neutron-rich nuclei indicate that the ideal manifestation of the chirality can be realised in 106Rh and 112Ag , where the doublet bands have similar electromagnetic properties along with small differences in excitation energies.

  11. 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.

  12. Instability and Transition of Flow at, and Near, an Attachment-line - Including Control by Surface Suction

    NASA Technical Reports Server (NTRS)

    Smith, A.

    1996-01-01

    Advances in aviation during and following the Second World War led to an enormous improvement in the performance of aircraft. The push for enhanced efficiency brought cruise speeds into the transonic range, where the associated drag rise due to the appearance of shock-waves became a limiting factor. Wing sweep was adopted to delay the onset of this drag rise, but with this development came several new and unforeseen problems. Preliminary theoretical work assumed that the boundary layer transition characteristics of a swept wing would be subject to the independence principle, so the chordwise transition position could be predicted from two-dimensional work Gas turbine development has now reached a point where additional increases in efficiency are both difficult and expensive to achieve. Consequently, aircraft manufacturers are looking elsewhere for ways to reduce Direct Operating Costs (DOC's) or increase military performance. The attention of industry is currently focusing on Hybrid Laminar Flow Control (HLFC) as a possible method of reducing DOC's for civil aircraft. Following this study and discussions with NASA Langley and Boeing a different series of questions have been addressed in the present work. There are five areas of interest: Relaminarisation of the attachment-line boundary layer when the value of R exceeds 600. The effects of large suction levels on transition in the attachment-line boundary layer (ie critical oversuction). The transition characteristics of a relaminarised attachment-line flow which encounters a non-porous surface. The effect of attachment-line suction on the spanwise propagation of gross disturbances emanating from the wing-fuselage junction. The attachment-line transition caused by surface blowing.

  13. Quasiequilibrium models for triaxially deformed rotating compact stars

    SciTech Connect

    Huang Xing; Markakis, Charalampos; Sugiyama, Noriyuki; Uryu, Koji

    2008-12-15

    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.

  14. Fracture of sedimentary rocks under a complex triaxial stress state

    NASA Astrophysics Data System (ADS)

    Karev, V. I.; Klimov, D. M.; Kovalenko, Yu. F.; Ustinov, K. B.

    2016-09-01

    Most sedimentary rocks have layered structure, and their strength properties are therefore anisotropic; as a consequence, the rock strength depends on the direction of the applied stresses. In this case, various fracture mechanisms are possible. The following two possible fracture mechanisms are considered: actions along the bedding planes, which are weakening surfaces, and along the planes where stresses exceeding the total rock strength are attained. A triaxial independent loading test bench was used to study the fracture conditions for layered rocks composed of productive oil-and-gas strata in complex true triaxial loading tests. The study shows a good qualitative agreement between experimental results and theoretical estimates.

  15. Triaxiality near the 110Ru ground state from Coulomb excitation

    NASA Astrophysics Data System (ADS)

    Doherty, D. T.; Allmond, J. M.; Janssens, R. V. F.; Korten, W.; Zhu, S.; Zielińska, M.; Radford, D. C.; Ayangeakaa, A. D.; Bucher, B.; Batchelder, J. C.; Beausang, C. W.; Campbell, C.; Carpenter, M. P.; Cline, D.; Crawford, H. L.; David, H. M.; Delaroche, J. P.; Dickerson, C.; Fallon, P.; Galindo-Uribarri, A.; Kondev, F. G.; Harker, J. L.; Hayes, A. B.; Hendricks, M.; Humby, P.; Girod, M.; Gross, C. J.; Klintefjord, M.; Kolos, K.; Lane, G. J.; Lauritsen, T.; Libert, J.; Macchiavelli, A. O.; Napiorkowski, P. J.; Padilla-Rodal, E.; Pardo, R. C.; Reviol, W.; Sarantites, D. G.; Savard, G.; Seweryniak, D.; Srebrny, J.; Varner, R.; Vondrasek, R.; Wiens, A.; Wilson, E.; Wood, J. L.; Wu, C. Y.

    2017-03-01

    A multi-step Coulomb excitation measurement with the GRETINA and CHICO2 detector arrays was carried out with a 430-MeV beam of the neutron-rich 110Ru (t1/2 = 12 s) isotope produced at the CARIBU facility. This represents the first successful measurement following the post-acceleration of an unstable isotope of a refractory element. The reduced transition probabilities obtained for levels near the ground state provide strong evidence for a triaxial shape; a conclusion confirmed by comparisons with the results of beyond-mean-field and triaxial rotor model calculations.

  16. Triaxiality near the 110Ru ground state from Coulomb excitation

    DOE PAGES

    Doherty, D. T.; Allmond, James M.; Janssens, R. V. F.; ...

    2017-01-20

    A multi-step Coulomb excitation measurement with the GRETINA and CHICO2 detector arrays was carried out with a 430-MeV beam of the neutron-rich 110Ru (t1/2 = 12 s) isotope produced at the CARIBU facility. This represents the first successful measurement following the post-acceleration of an unstable isotope of a refractory element. The reduced transition probabilities obtained for levels near the ground state provide strong evidence for a triaxial shape; a conclusion confirmed by comparisons with the results of beyond-mean-field and triaxial rotor model calculations.

  17. 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.

  18. 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

  19. 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.

  20. Loading and Boundary Condition Influences in a Poroelastic Finite Element Model of Cartilage Stresses in a Triaxial Compression Bioreactor

    PubMed Central

    Kallemeyn, Nicole A; Grosland, Nicole M; Pedersen, Doug R; Martin, James A; Brown, Thomas D

    2006-01-01

    Background: We developed a poroelastic finite element (FE) model of cartilage in dynamic triaxial compression to parametrically analyze the effects of loading and boundary conditions on a baseline model. Conventional mechanical tests on articular cartilage such as confined and unconfined compression, indentation, etc., do not fully allow for modulation of compression and shear at physiological levels whereas triaxial compression does. A Triaxial Compression Bioreactor, or TRIAX, has been developed to study chondrocyte responses to multi-axial stress conditions under cyclic loading. In the triaxial setting, however, a cartilage explant's physical testing environment departs from the ideal homogeneous stress state that would occur from strict linear superposition of the applied axial and transverse pressure. Method of Approach: An axisymmetric poroelastic FE model of a cartilage explant (4 mm diameter, 1.5 mm thick) in cyclic triaxial compression was created. Axial and transverse loads (2 MPa at 1 Hz.) were applied via a platen and containment sheath. Parameters of interest included the rise time and magnitude of the applied load, in addition to the containment sheath modulus and the friction coefficient at the cartilage/platen interfaces. Metrics of interest in addition to whole explant axial strain included axial (surface normal) stress, shear stress, pore pressure, and the fluid load carriage fraction within the explant. Results: Strain results were compared to experimental data from explants tested in the TRIAX under conditions similar to the baseline model. Explant biomechanics varied considerably over numbers of load cycles and parameter values. Cyclic loading caused an increase in accumulated strain for the various loading and boundary conditions. Conclusions: Unlike what would be expected from linear superposition of the homogeneous stresses from the applied axial and transverse pressure, we have shown that the stress state within the TRIAX is considerably

  1. Role of triaxiality in 76Ge and 76Se nuclei studied with Gogny energy density functionals

    NASA Astrophysics Data System (ADS)

    Rodríguez, Tomás R.

    2017-03-01

    The structure of the nuclei 76Ge and 76Se is studied with symmetry conserving configuration mixing methods based on the Gogny D1S interaction. These two nuclei are of key importance in the search for neutrinoless double-beta decay. The energy density functionals used here include symmetry restorations (particle number and angular momentum) and shape mixing within the generator coordinate method. The comparison with the experimental data shows a good qualitative agreement when triaxial shapes are included, revealing the important role played by this degree of freedom in these two nuclei.

  2. High temperature triaxial tests on Rochester shale

    NASA Astrophysics Data System (ADS)

    Bruijn, Rolf; Burlini, Luigi; Misra, Santanu

    2010-05-01

    Phyllosilicates are one of the major components of the crust, responsible for strength weakening during deformation. High pressure and temperature experiments of natural samples rich in phyllosilicates are needed to test the relevance of proposed weakening mechanisms induced by phyllosilicates, derived from lab experiments on single phase and synthetic polyphase rocks and single crystals. Here, we present the preliminary results of a series of high temperature triaxial tests performed on the illite-rich Rochester Shale (USA - New York) using a Paterson type gas-medium HPT testing machine. Cylindrical samples with homogeneous microstructure and 12-14% porosity were fabricated by cold and hot-isostatically pressing, <150 μm crushed Rochester Shale particles. Experiments were conducted at 500- 700 °C temperature and varying strain rate from 5x10-6 to 7x10-4 s-1, while keeping confining pressure constant at 300 MPa. Synthetic hot-pressed samples were deformed up to a total shortening of 7.5 to 13%. To study the significance of mica dehydration, iron or copper jackets were used in combination with non-porous or porous spacers. Water content was measured before and after experiments using Karl Fischer Titration (KFT). All experiments show, after yielding at 0.6% strain, rapid hardening in nearly linear fashion until about 4-5% strain, from where stress increases at reducing rates to values at 10% strain, between 400 and 675 MPa, depending on experimental conditions. Neither failure nor steady state however, is achieved within the maximum strain of 13%. Experiments performed under 500 °C and 300 MPa confining pressure show weak strain rate dependence. In addition, iron-jacketed samples appear harder than copper-jacketed ones. At 700 °C samples are 17 to 37% weaker and more sensitive to strain rate than during 500 °C experiments. Although, iron-jacketed samples behave stronger than copper-jacketed ones. By visual inspection, samples appear homogeneously shortened

  3. 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.

  4. Beyond-mean-field effects on nuclear triaxiality

    NASA Astrophysics Data System (ADS)

    Ya, Tu; Chen, Yong-Shou; Gao, Zao-Chun; Liu, Ling; Chen, Yong-Jing

    2017-06-01

    The beyond-mean-field effects on nuclear triaxiality are studied by applying the projected total energy surface (PTES) calculations to the light tungsten isotopes -178W170, which have been well described as prolate rotors within the mean-field approximation. The present PTES calculations have well reproduced the experimental energies of the yrast states and the available experimental transition quardrupole moment (Qt) in function of spin. In particular, the results present a considerable large triaxiality for their ground states, with an average triaxial deformation γ ˜15∘ . For a comparison, the total Routhian surface calculations have also been performed for these nuclei, the results show a well-established axial quadrupole deformation in their ground states. The presence of the significant triaxial deformation can be attributed to the beyond-mean-field effect as the angular momentum projection. This effect is therefore essential for a variety of mean-field approaches since it is only associated with the necessary restoration of the rotational symmetry in the laboratory frame, which is spontaneously broken in the intrinsic frame.

  5. 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.

  6. 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…

  7. Periodic Orbits Around a Satellite Modelled as a Triaxial Ellipsoid.

    DTIC Science & Technology

    There are planetary satellites, particularly Phobos , which can be modeled s triaxial ellipsoids. To study orbital dynamics of a mass near such a...Calculations were also done to check the stability of these orbits by evaluating the Poincare exponents. for Phobos , periodic orbits were found in Phobos’s

  8. 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.

  9. 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.

  10. 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

  11. 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…

  12. A fast algorithm for estimating actions in triaxial potentials

    NASA Astrophysics Data System (ADS)

    Sanders, Jason L.; Binney, James

    2015-03-01

    We present an approach to approximating rapidly the actions in a general triaxial potential. The method is an extension of the axisymmetric approach presented by Binney, and operates by assuming that the true potential is locally sufficiently close to some Stäckel potential. The choice of Stäckel potential and associated ellipsoidal coordinates is tailored to each individual input phase-space point. We investigate the accuracy of the method when computing actions in a triaxial Navarro-Frenk-White potential. The speed of the algorithm comes at the expense of large errors in the actions, particularly for the box orbits. However, we show that the method can be used to recover the observables of triaxial systems from given distribution functions to sufficient accuracy for the Jeans equations to be satisfied. Consequently, such models could be used to build models of external galaxies as well as triaxial components of our own Galaxy. When more accurate actions are required, this procedure can be combined with torus mapping to produce a fast convergent scheme for action estimation.

  13. Estimation of resistance exercise energy expenditure using triaxial accelerometry.

    PubMed

    Stec, Michael J; Rawson, Eric S

    2012-05-01

    Recently, it was demonstrated that a uniaxial accelerometer worn at the hip could estimate resistance exercise energy expenditure. As resistance exercise takes place in more than 1 plane, the use of a triaxial accelerometer may be more effective in estimating resistance exercise energy expenditure. The aims of this study were to estimate the energy cost of resistance exercise using triaxial accelerometry and to determine the optimal location for wearing triaxial accelerometers during resistance exercise. Thirty subjects (15 men and 15 women; age = 21.7 ± 1.0 years) performed a resistance exercise protocol consisting of 2 sets of 8 exercises (10RM loads). During the resistance exercise protocol, subjects wore triaxial accelerometers on the wrist, waist, and ankle; a heart rate monitor; and a portable metabolic system. Net energy expenditure was significantly correlated with vertical (r = 0.67, p < 0.001), horizontal (r = 0.43, p = 0.02), third axis (r = 0.36, p = 0.048), and sum of 3 axes (r = 0.50, p = 0.005) counts at the waist, and horizontal counts at the wrist (r = -0.40, p = 0.03). Regression analysis using fat-free mass, sex, and the sum of accelerometer counts at the waist as variables was used to develop an equation that explained 73% of the variance of resistance exercise energy expenditure. A triaxial accelerometer worn at the waist can be used to estimate resistance exercise energy expenditure but appears to offer no benefit over uniaxial accelerometry. The use of accelerometers in estimating resistance exercise energy expenditure may prove useful for individuals and athletes who participate in resistance training and are focused on maintaining a tightly regulated energy balance.

  14. 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

  15. 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.

  16. SYNTHESIZED SPECTRA OF OPTICALLY THIN EMISSION LINES PRODUCED BY THE BIFROST STELLAR ATMOSPHERE CODE, INCLUDING NONEQUILIBRIUM IONIZATION EFFECTS: A STUDY OF THE INTENSITY, NONTHERMAL LINE WIDTHS, AND DOPPLER SHIFTS

    SciTech Connect

    Olluri, K.; Gudiksen, B. V.; Hansteen, V. H.; Pontieu, B. De

    2015-03-20

    In recent years realistic 3D numerical models of the solar atmosphere have become available. The models attempt to recreate the solar atmosphere and mimic observations in the best way, in order to make it possible to couple complicated observations with physical properties such as the temperatures, densities, velocities, and magnetic fields. We here present a study of synthetic spectra created using the Bifrost code in order to assess how well they fit with previously taken solar data. A study of the synthetic intensity, nonthermal line widths, Doppler shifts, and correlations between any two of these three components of the spectra first assuming statistical equilibrium is made, followed by a report on some of the effects nonequilibrium ionization will have on the synthesized spectra. We find that the synthetic intensities compare well with the observations. The synthetic observations depend on the assumed resolution and point-spread function (PSF) of the instrument, and we find a large effect on the results, especially for intensity and nonthermal line width. The Doppler shifts produce the reported persistent redshifts for the transition region (TR) lines and blueshifts for the upper TR and corona lines. The nonthermal line widths reproduce the well-known turnoff point around (2–3) × 10{sup 5} K, but with much lower values than those observed. The nonthermal line widths tend to increase with decreasing assumed instrumental resolution, also when nonequilibrium ionization is included. Correlations between the nonthermal line width of any two TR line studies as reported by Chae et al. are reproduced, while the correlations of intensity to line width are reproduced only after applying a PSF to the data. Doppler shift correlations reported by Doschek for the TR lines and correlations of Doppler shift to nonthermal line width of the Fe xii{sub 19.5} line reported by Doschek et al. are reproduced.

  17. Recovery time analysis in a tri-axial HTS cable after an over-current fault

    NASA Astrophysics Data System (ADS)

    Hu, N.; Toda, M.; Watanabe, T.; Tsuda, M.; Hamajima, T.

    2011-11-01

    A tri-axial HTS cable with the advantage of compact structure, low heat loss, and low cost is a perfect solution for future distribution power network demand. In our previous research, a typical single line to ground (SLG) fault simulation was carried out in an adiabatic condition. A stabilizer layer thickness design of the tri-axial HTS cable based on a calculation of maximum temperature rise in the worst condition was proposed. However, in practical application, after the quenched cable is removed from the network by a breaker, a recovery time is also a very important parameter to decide if the cable is allowed to reconnect to the power network. In this paper, a one-dimensional computational fluid dynamics (CFD) analysis is carried out to simulate the transient thermal behavior of the cable. 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. Since the cable is cooled by forced liquid nitrogen (LN2) flow, there is a temperature gradient along the cable. The temperature of LN2 gradually rises after the fault until the warmed coolant runs out of the cable.

  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. Decay rate of critical fluctuations in ethane+carbon dioxide mixtures near the critical line including the critical azeotrope

    SciTech Connect

    Chang, R.F.; Doiron, T.; Pegg, I.L.; Hanley, H.J.M.; Cezairliyan, A.

    1986-03-01

    Using the technique of photon correlation spectroscopy we have measured the decay rate of critical fluctuations in mixtures of ethane and carbon dioxide of various compositions including a near-azeotropic mixture. Our experimental data indicate that there is only one dominant mode of fluctuations and the decay rate is well described by the predictions of the mode-coupling theory with the exponent v=0.63 for all compositions. The decay rate, its background contributions, the shear viscosity, and the correlation length for the mixtures appear to interpolate simply between those of ethane and carbon dioxide.

  20. Comparison of gait symmetry between poststroke fallers and nonfallers during level walking using triaxial accelerometry

    PubMed Central

    Lien, Wei-Chih; Cheng, Yung-Heng; Kuan, Ta-Shen; Zheng, Yu-Lun; Hsieh, Chao-Hsien; Wang, Wen-Fong

    2017-01-01

    Abstract To compare the degree of gait symmetry of chronic poststroke fallers with that of nonfallers during level walking using triaxial accelerometry. In this cross-sectional study, a total of 14 patients with chronic stroke were recruited from a community hospital from February 2015 to July 2016. Patient characteristics, including the number of falls in the previous 12 months, were obtained from medical records. The Berg Balance Scale (BBS) and timed up and go (TUG) test were used at the onset of the study. Triaxial accelerometers were attached to the back and bilateral lower extremities of each subject with sampling rates of 120 Hz. The cross-correlation between the acceleration signals of the affected and unaffected feet was measured to assess the degree of gait symmetry. The triaxial acceleration signals of the 5 consecutive and bilateral strides from the middle of each trial were processed to measure the cross-correlation and time delay (Ts) between the magnitude of the acceleration vector of the affected and unaffected foot. After controlling for possible confounding factors, the mixed-effect models showed that cross-correlation was significantly higher among nonfallers than fallers (β = −0.093; standard error [SE] = 0.029; P-value = 0.002), and that the Ts was significantly longer among fallers than nonfallers (β = −1.900; SE = 0.719; P-value = 0.011). Cross-correlation and Ts between the affected and unaffected lower extremities may be useful indicators to distinguish poststroke fallers from nonfallers. PMID:28248856

  1. Lines

    ERIC Educational Resources Information Center

    Mires, Peter B.

    2006-01-01

    National Geography Standards for the middle school years generally stress the teaching of latitude and longitude. There are many creative ways to explain the great grid that encircles our planet, but the author has found that students in his college-level geography courses especially enjoy human-interest stories associated with lines of latitude…

  2. Lines

    ERIC Educational Resources Information Center

    Mires, Peter B.

    2006-01-01

    National Geography Standards for the middle school years generally stress the teaching of latitude and longitude. There are many creative ways to explain the great grid that encircles our planet, but the author has found that students in his college-level geography courses especially enjoy human-interest stories associated with lines of latitude…

  3. Measurements of aerosol-cloud interactions, including on-line particle chemical composition, at the Jungfraujoch Global Atmospheric Watch Station

    NASA Astrophysics Data System (ADS)

    Coe, H.; Allan, J. D.; Alfarra, M. R.; Williams, P. I.; Bower, K. N.; Gallagher, M. W.; Choularton, T. W.; Weingartner, E.; Corrigan, C.; Baltensperger, U.

    2003-04-01

    The Global Atmospheric Watch research laboratory is located in the Sphinx building, 3580 m asl; 46.55oN, 7.98oE on the Jungfraujoch in the Swiss Alps. The site is exposed to a wide range of conditions and frequently samples long range transported lower free tropospheric air, and is exposed to cloudy conditions. The Paul Scherrer Institute have previously developed a dual inlet system that allows measurements of the total sub-micron aerosol population (dry residuals and interstitial particles) and interstitial particles alone to be made alternately every few minutes. During July 2002 an Aerodyne Aerosol Mass Spectrometer was coupled to the dual inlet and was used to sample the composition of both the total particle distribution and the interstitial fraction and hence derive the mass loadings of the dry droplet residuals. In out of cloud conditions the aerosol composition can be linked to air mass history and age of the air mass. Microphysical measurements include cloud droplet size distributions made using an FSSP and also a new phase Doppler anemometry system. A comparison between these probes will be made. Two different types of cloud droplet spectra were observed. In the first type a large number of cloud droplets were measured with a single, narrow drop size distribution and modal diameter of around 10 um. In the second type, a bimodal cloud droplet spectrum occurred with a smaller mode (by number) at around 20 um, in addition to the 10 um mode. The aerosol mass spectrometry shows that the composition of the residuals from the two spectrum types is very different, the former type being composed mainly of sulphate, the latter a combination of nitrate, sulphate and organic material. We have also shown that the organic material observed is highly oxidized. We argue that the bimodality arises as a result of mixing of cloud droplets below the site that have been activated separately: the larger a less numerous mode in the widespread strato-cumulus forming under low

  4. Texture and Microstructural Evolution in Pearlitic Steel During Triaxial Compression

    NASA Astrophysics Data System (ADS)

    Kumar, Pankaj; Gurao, Nilesh P.; Haldar, Arunansu; Suwas, Satyam

    2012-06-01

    This article presents the deformation behavior of high-strength pearlitic steel deformed by triaxial compression to achieve ultra-fine ferrite grain size with fragmented cementite. The consequent evolution of microstructure and texture has been studied using scanning electron microscopy, electron back-scatter diffraction, and X-ray diffraction. The synergistic effect of diffusion and deformation leads to the uniform dissolution of cementite at higher temperature. At lower temperature, significant grain refinement of ferrite phase occurs by deformation and exhibits a characteristic deformation texture. In contrast, the high-temperature deformed sample shows a weaker texture with cube component for the ferrite phase, indicating the occurrence of recrystallization. The different mechanisms responsible for the refinement of ferrite as well as the fragmentation of cementite and their interaction with each other have been analyzed. Viscoplastic self-consistent simulation was employed to understand deformation texture in the ferrite phase during triaxial compression.

  5. Low frequency/high sensitivity triaxial monolithic sensor

    NASA Astrophysics Data System (ADS)

    Acernese, F.; Canonico, R.; De Rosa, R.; Giordano, G.; Romano, R.; Barone, F.

    2013-04-01

    This paper describes a new mechanical implementation of a triaxial sensor, configurable as seismometer and/or as accelerometer, consisting of three one-dimensional monolithic FP sensors, suitably geometrically positioned. The triaxial sensor is, therefore, compact, light, scalable, tunable instrument (frequency < 100 mHz with large band (10-7 Hz - 10 Hz), high quality factor (Q < 1500 in air) with good immunity to environmental noises, guaranteed by an integrated laser optical readout. The measured sensitivity curve is in very good agreement with the theoretical ones (10-12m/√Hz) in the band (0.1 ÷ 10Hz). Typical applications are in the field of earthquake engineering, geophysics, civil engineering and in all applications requiring large band-low frequency performances coupled with high sensitivities.

  6. Very low frequency/high sensitivity triaxial monolithic inertial sensor

    NASA Astrophysics Data System (ADS)

    Acernese, F.; De Rosa, R.; Giordano, G.; Romano, R.; Barone, F.

    2014-03-01

    This paper describes a new mechanical implementation of a triaxial sensor, configurable as seismometer and/or as accelerometer, consisting of three one-dimensional monolithic FP sensors, suitably geometrically positioned. The triaxial sensor is, therefore, compact, light, scalable, tunable instrument (frequency < 100mHz), with large band (10-7 Hz - 10Hz), high quality factor (Q > 2500 in air) with good immunity to environmental noises, guaranteed by an integrated laser optical readout. The measured sensitivity curve is in very good agreement with the theoretical ones (10-12m/√Hz) in the band (0.1 ÷ 10Hz). Typical applications are in the field of earthquake engineering, geophysics, civil engineering and in all applications requiring large band-low frequency performances coupled with high sensitivities.

  7. Low frequency/high sensitivity triaxial monolithic inertial sensor

    NASA Astrophysics Data System (ADS)

    Acernese, F.; De Rosa, R.; Giordano, G.; Romano, Rocco; Barone, F.

    2013-10-01

    This paper describes a new mechanical implementation of a triaxial sensor, configurable as seismometer and/or as accelerometer, consisting of three one-dimensional monolithic FP sensors, suitably geometrically positioned. The triaxial sensor is, therefore, compact, light, scalable, tunable instrument (frequency < 100mHz), with large band (10-7 Hz - 10Hz), high quality factor (Q < 2500 in air) with good immunity to environmental noises, guaranteed by an integrated laser optical readout. The measured sensitivity curve is in very good agreement with the theoretical ones (10-12m/pHz) in the band (0.1 ÷ 10Hz). Typical applications are in the field of earthquake engineering, geophysics, civil engineering and in all applications requiring large band-low frequency performances coupled with high sensitivities.

  8. 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.

  9. Space acceleration measurement system triaxial sensor head error budget

    NASA Technical Reports Server (NTRS)

    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.

  10. 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.

  11. Using triaxial magnetic fields to create high susceptibility particle composites.

    PubMed

    Martin, James E; Venturini, Eugene; Gulley, Gerald L; Williamson, Jonathan

    2004-02-01

    We report on the use of triaxial magnetic fields to create a variety of isotropic and anisotropic magnetic particle/polymer composites with significantly enhanced magnetic susceptibilities. A triaxial field is a superposition of three orthogonal ac magnetic fields, each generated by a Helmholtz coil in series resonance with a tunable capacitor bank. Field frequencies are in the range of 150-400 Hz. Because both the field amplitudes and frequencies can be varied, a rich variety of structures can be created. Perhaps the most unusual effects occur when either two or three of the field components are heterodyned to give beat frequencies on the order of 1 Hz. This leads to a striking particle dynamics that evolves into surprising structures during resin gelation. These structures are found to have perhaps the highest susceptibility that a particle composite can have. The susceptibility anisotropy of these composites can be controlled over a wide range by judicious adjustment of the relative field amplitudes. These experimental data are supported by large-scale Brownian dynamics simulations of the complex many-body interactions that occur in triaxial magnetic fields. These simulations show that athermal three-dimensional field heterodyning leads to structures with a susceptibility that is as high as that achieved with thermal annealing. Thus with coherent particle motions we can achieve magnetostatic energies that are quite close to the ground state.

  12. Behavior of asphalt concrete mixtures in triaxial compression

    SciTech Connect

    Tan Siewann; Low Boonhwee; Fwa Tienfang . Dept. of Civil Engineering)

    1994-05-01

    The triaxial compression test is one of the most common standard tests for determining the stress-strain behavior and strength parameters of soil under drained and undrained conditions. The use of the test method in asphaltic mixtures is less well known and seldom practiced. This paper describes the use of the triaxial compression test for asphaltic mixtures for determining their engineering properties such as the friction angle [phi], the cohesion, c, and the elastic compression modulus, E. Effects of test temperatures, strain rates, and confining pressures on the compressive behavior of asphalt concrete were studied. The results showed that the friction angle is primarily a function of aggregate friction and interlocking being independent of test temperature and strain rate. The cohesion, on the other hand, is largely dependent on the binder and fines mixture being sensitive to both test temperature and strain rate changes. The confining pressures have no influence on c and [phi], but have significant influence on the compression modulus, E. The tests can be conducted at controlled temperatures, constant strain-rate, and confining pressures so as to allow the determination of the basic engineering stress-strain and strength properties of these materials under controlled environmental conditions. Using these properties, a constitutive plasticity model based on the Drucker-Prager yield condition can then be applied in the axisymmetric finite element model to describe the mechanical behavior of the asphaltic material in triaxial compression.

  13. 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.

  14. 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.

  15. An analytical treatment of single station triaxial seismic direction finding

    NASA Astrophysics Data System (ADS)

    Greenhalgh, S.; Mason, I. M.; Zhou, B.

    2005-03-01

    Triaxial seismic direction finding can be performed by eigenanalysis of the complex coherency matrix (or cross power matrix). By splitting the symmetric Hermitian coherency matrix C to D + E (where det(E) = 0 and D is diagonal), we shift unpolarized (or inter-channel uncorrelated) data into D and then E becomes 'random noise free'. Without placing any restrictions on the signal set—P, S, Rayleigh—matrix E has only one non-zero eigenvalue (at least for the case of a single mode arriving from a single direction). But for real data (polychromatic transients with correlated noise), it will have two non-zero eigenvalues. By rotating one axis of the triaxial geophone recorded signals to lie normal to the principal eigenvector, it is possible to reduce the coherency matrix from a 3 × 3 to a 2 × 2 matrix. For the case of a perfectly polarized monochromatic signal, we interpret this to mean that the particle trajectory can only be elliptical. It seems as though particles can only move in a plane: they cannot move in three dimensions. In practice, the signal is made up of a band of frequencies, there are multiple arrivals in the time window of interest, and noise is invariably present, which causes the ellipse to wobble in a 3D orbit. Explicit analytical expressions are derived in this paper to yield the eigenvalues and eigenvectors of the coherency matrix in terms of the triaxial signal amplitudes and phases.

  16. A study of aneuploidy and DNA fragmentation in spermatozoa of three men with sex chromosome mosaicism including a 45,X cell line.

    PubMed

    Nguyen, Minh Huong; Morel, Frederic; Bujan, Louis; May-Panloup, Pascale; De Braekeleer, Marc; Perrin, Aurore

    2015-06-01

    Meiotic segregation of mosaic males with a 45,X cell line has been little examined. In this study, we evaluated the risk of aneuploid gametes using fluorescence in situ hybridization (FISH) and DNA fragmentation in ejaculated spermatozoa of three men with sex chromosome mosaicism including a 45,X cell line. Triple- and dual-color FISH were performed. Sperm DNA fragmentation was detected using the TUNEL assay. A significantly increased frequency of XY disomic spermatozoa was observed for patients (P)1 and P2. A significant increase in diploidy and autosomal aneuploidy was found in P2 and P3, respectively. The rate of DNA fragmentation was not different from that observed in a control group. Data from the literature are scarce (only 3 cases reported), making comparison of the present data difficult, especially as the frequencies of the cell lines comprising the mosaicism differed between patients. Furthermore, the proportion of the different cell lines can differ from one tissue to another in the same patient. Whether the relative levels of the several cell lines present in the mosaicism can influence the rate of aneuploid spermatozoa remains unknown.

  17. Test Results and Comparison of Triaxial Strength Testing of Waste Isolation Pilot Plant Clean Salt

    SciTech Connect

    Buchholz, Stuart A.

    2016-12-01

    This memorandum documents laboratory thermomechanical triaxial strength testing of Waste Isolation Pilot Plant (WIPP) clean salt. The limited study completed independent, adjunct laboratory tests in the United States to assist in validating similar testing results being provided by the German facilities. The testing protocol consisted of completing confined triaxial, constant strain rate strength tests of intact WIPP clean salt at temperatures of 25°C and 100°C and at multiple confining pressures. The stratigraphy at WIPP also includes salt that has been labeled “argillaceous.” The much larger test matrix conducted in Germany included both the so-called clean and argillaceous salts. When combined, the total database of laboratory results will be used to develop input parameters for models, assess adequacy of existing models, and predict material behavior. These laboratory studies are also consistent with the goals of the international salt repository research program. The goal of this study was to complete a subset of a test matrix on clean salt from the WIPP undertaken by German research groups. The work was performed at RESPEC in Rapid City, South Dakota. A rigorous Quality Assurance protocol was applied, such that corroboration provides the potential of qualifying all of the test data gathered by German research groups.

  18. Triaxial Measurement Method for Analysis of Residual Stress after High Feed Milling by X-Ray Diffraction

    NASA Astrophysics Data System (ADS)

    Čuma, Matúš; Török, Jozef; Telišková, Monika

    2016-12-01

    Surface integrity is a broad term which includes various quality factors affecting the functional properties of parts. Residual stress is one of these factors. Machining generates residual stresses in the surface and subsurface layers of the structural elements. X-ray diffractometry is a non-destructive method applicable for the measurement of residual stresses in surface and subsurface layers of components. The article is focused on the non-destructive progressive method of triaxial measurement of residual stress after machining the surface of sample by high feed milling technology. Significance of triaxial measuring is the capability of measuring in different angles so it is possible to acquire stress tensor containing normal and shear stress components acting in the spot of measuring, using a Cartesian coordinate system.

  19. 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.

  20. 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.

  1. 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.

  2. Magnetic field uniformity of the practical tri-axial Helmholtz coils systems.

    PubMed

    Beiranvand, R

    2014-05-01

    In this paper, effects of the assembly misalignments and the manufacturing mismatches on the magnetic field uniformity of a practical tri-axial Helmholtz coils system have been modeled mathematically. These undesired effects regularly occur in any practical tri-axial Helmholtz coils system. To confirm the mathematical calculations, a tri-axial Helmholtz coils system has been constructed and the uniformity of its magnetic field has been measured under different conditions. The experimental results are in good agreement with the mathematical analyses.

  3. DETECTING TRIAXIALITY IN THE GALACTIC DARK MATTER HALO THROUGH STELLAR KINEMATICS. II. DEPENDENCE ON NATURE DARK MATTER AND GRAVITY

    SciTech Connect

    Rojas-Niño, Armando; Pichardo, Barbara; Valenzuela, Octavio; Martínez-Medina, Luis A. E-mail: octavio@astro.unam.mx

    2015-05-20

    Recent studies have presented evidence that the Milky Way global potential may be non-spherical. In this case, the assembling process of the Galaxy may have left long-lasting stellar halo kinematic fossils due to the shape of the dark matter halo, potentially originated by orbital resonances. We further investigate such a possibility, now considering potential models further away from ΛCDM halos, like scalar field dark matter halos and Modified Newtonian Dynamics (MOND), and including several other factors that may mimic the emergence and permanence of kinematic groups, such as a spherical and triaxial halo with an embedded disk potential. We find that regardless of the density profile (DM nature), kinematic groups only appear in the presence of a triaxial halo potential. For the case of a MOND-like gravity theory no kinematic structure is present. We conclude that the detection of these kinematic stellar groups could confirm the predicted triaxiality of dark halos in cosmological galaxy formation scenarios.

  4. 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).

  5. Spectral Line Parameters Including Temperature Dependences of Self- and Air-Broadening in the 2 (left arrow) 0 Band of CO at 2.3 micrometers

    NASA Technical Reports Server (NTRS)

    Devi, V. Malathy; Benner, D. Chris; Smith, M. A. H.; Mantz, A. W.; Sung, K.; Brown, L. R.; Predoi-Cross, A.

    2012-01-01

    Temperature dependences of pressure-broadened half-width and pressure-induced shift coefficients along with accurate positions and intensities have been determined for transitions in the 2<--0 band of C-12 O-16 from analyzing high-resolution and high signal-to-noise spectra recorded with two different Fourier transform spectrometers. A total of 28 spectra, 16 self-broadened and 12 air-broadened, recorded using high- purity (greater than or equal to 99.5% C-12-enriched) CO samples and CO diluted with dry air(research grade) at different temperatures and pressures, were analyzed simultaneously to maximize the accuracy of the retrieved parameters. The sample temperatures ranged from 150 to 298K and the total pressures varied between 5 and 700 Torr. A multispectrum nonlinear least squares spectrum fitting technique was used to adjust the rovibrational constants (G, B, D, etc.) and intensity parameters (including Herman-Wallis coefficients), rather than determining individual line positions and intensities. Self-and air-broadened Lorentz half-width coefficients, their temperature dependence exponents, self- and air-pressure-induced shift coefficients, their temperature dependences, self- and air-line mixing coefficients, their temperature dependences and speed dependence have been retrieved from the analysis. Speed-dependent line shapes with line mixing employing off-diagonal relaxation matrix element formalism were needed to minimize the fit residuals. This study presents a precise and complete set of spectral line parameters that consistently reproduce the spectrum of carbon monoxide over terrestrial atmospheric conditions.

  6. Spectral Line Parameters Including Temperature Dependences of Self- and Air-Broadening in the 2 (left arrow) 0 Band of CO at 2.3 micrometers

    NASA Technical Reports Server (NTRS)

    Devi, V. Malathy; Benner, D. Chris; Smith, M. A. H.; Mantz, A. W.; Sung, K.; Brown, L. R.; Predoi-Cross, A.

    2012-01-01

    Temperature dependences of pressure-broadened half-width and pressure-induced shift coefficients along with accurate positions and intensities have been determined for transitions in the 2<--0 band of C-12 O-16 from analyzing high-resolution and high signal-to-noise spectra recorded with two different Fourier transform spectrometers. A total of 28 spectra, 16 self-broadened and 12 air-broadened, recorded using high- purity (greater than or equal to 99.5% C-12-enriched) CO samples and CO diluted with dry air(research grade) at different temperatures and pressures, were analyzed simultaneously to maximize the accuracy of the retrieved parameters. The sample temperatures ranged from 150 to 298K and the total pressures varied between 5 and 700 Torr. A multispectrum nonlinear least squares spectrum fitting technique was used to adjust the rovibrational constants (G, B, D, etc.) and intensity parameters (including Herman-Wallis coefficients), rather than determining individual line positions and intensities. Self-and air-broadened Lorentz half-width coefficients, their temperature dependence exponents, self- and air-pressure-induced shift coefficients, their temperature dependences, self- and air-line mixing coefficients, their temperature dependences and speed dependence have been retrieved from the analysis. Speed-dependent line shapes with line mixing employing off-diagonal relaxation matrix element formalism were needed to minimize the fit residuals. This study presents a precise and complete set of spectral line parameters that consistently reproduce the spectrum of carbon monoxide over terrestrial atmospheric conditions.

  7. Principal component analysis for ataxic gait using a triaxial accelerometer.

    PubMed

    Matsushima, Akira; Yoshida, Kunihiro; Genno, Hirokazu; Ikeda, Shu-Ichi

    2017-05-02

    It is quite difficult to evaluate ataxic gait quantitatively in clinical practice. The aim of this study was to analyze the characteristics of ataxic gait using a triaxial accelerometer and to develop a novel biomarker of integrated gate parameters for ataxic gait. Sixty-one patients with spinocerebellar ataxia (SCA) or multiple system atrophy with predominant cerebellar ataxia (MSA-C) and 57 healthy control subjects were enrolled. The subjects were instructed to walk 10 m for a total of 12 times on a flat floor at their usual walking speed with a triaxial accelerometer attached to their back. Gait velocity, cadence, step length, step regularity, step symmetry, and degree of body sway were evaluated. Principal component analysis (PCA) was used to analyze the multivariate gait parameters. The Scale for the Assessment and Rating of Ataxia (SARA) was evaluated on the same day of the 10-m walk trial. PCA divided the gait parameters into four principal components in the controls and into two principal components in the patients. The four principal components in the controls were similar to those found in earlier studies. The second principal component in the patients had relevant factor loading values for gait velocity, step length, regularity, and symmetry in addition to the degree of body sway in the medio-lateral direction. The second principal component score (PCS) in the patients was significantly correlated with disease duration and the SARA score of gait (ρ = -0.363, p = 0.004; ρ = -0.574, p < 0.001, respectively). PCA revealed the main component of ataxic gait. The PCS of the main component was significantly different between the patients and controls, and it was well correlated with disease duration and the SARA score of gait in the patients. We propose that this score provides a novel method to assess the severity of ataxic gait quantitatively using a triaxial accelerometer.

  8. Classifying household and locomotive activities using a triaxial accelerometer.

    PubMed

    Oshima, Yoshitake; Kawaguchi, Kaori; Tanaka, Shigeho; Ohkawara, Kazunori; Hikihara, Yuki; Ishikawa-Takata, Kazuko; Tabata, Izumi

    2010-03-01

    The purpose of this study was to develop a new algorithm for classifying physical activity into either locomotive or household activities using a triaxial accelerometer. Sixty-six volunteers (31 men and 35 women) participated in this study and were separated randomly into validation and cross-validation groups. All subjects performed 12 physical activities (personal computer work, laundry, dishwashing, moving a small load, vacuuming, slow walking, normal walking, brisk walking, normal walking while carrying a bag, jogging, ascending stairs and descending stairs) while wearing a triaxial accelerometer in a controlled laboratory setting. Each of the three signals from the triaxial accelerometer was passed through a second-order Butterworth high-pass filter to remove the gravitational acceleration component from the signal. The cut-off frequency was set at 0.7 Hz based on frequency analysis of the movements conducted. The ratios of unfiltered to filtered total acceleration (TAU/TAF) and filtered vertical to horizontal acceleration (VAF/HAF) were calculated to determine the cut-off value for classification of household and locomotive activities. When the TAU/TAF discrimination cut-off value derived from the validation group was applied to the cross-validation group, the average percentage of correct discrimination was 98.7%. When the VAF/HAF value similarly derived was applied to the cross-validation group, there was relatively high accuracy but the lowest percentage of correct discrimination was 63.6% (moving a small load). These findings suggest that our new algorithm using the TAU/TAF cut-off value can accurately classify household and locomotive activities. Copyright 2010 Elsevier B.V. All rights reserved.

  9. 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.

  10. The rotational stability of a triaxial ice-age Earth

    NASA Astrophysics Data System (ADS)

    Matsuyama, I.; Mitrovica, J. X.; Daradich, A.; Gomez, N.

    2010-05-01

    Mitrovica et al. (2005), following calculations by Nakada (2002), demonstrated that the traditional approach for computing rotation perturbations driven by glacial isostatic adjustment significantly overestimates present-day true polar wander (TPW) speeds by underestimating the background oblateness on which the ice-age loading is superimposed. The underestimation has two contributions: the first originates from the treatment of the hydrostatic form and the second from the neglect of the Earth's excess ellipticity supported by mantle convection. In Mitrovica et al. (2005), the second of these two contributions was computed assuming a biaxial nonhydrostatic form (i.e., the principal equatorial moments of inertia were assumed to be equal to their mean value). In this article we outline an extended approach that accounts for a triaxial planetary form. We show that differences in the TPW speed predicted using the Mitrovica et al. (2005) approach and our triaxial theory are relatively minor (˜0.1°/Myr) and are limited to Earth models with lower mantle viscosity less than ˜5 × 1021 Pa s. However, for this same class of Earth models, the angle of TPW predicted for a triaxial Earth is rotated westward (toward the axis of maximum equatorial inertia) by as much as ˜20° relative to the biaxial case. We demonstrate that these effects are a consequence of the geometry of the ice-age forcing, which has a dominant equatorial direction that is intermediate to the axes defining the principal equatorial moments of inertia of the planet. We complete the study by computing updated Frechet kernels for the TPW speed datum, which provide a measure of the detailed depth-dependent sensitivity of the predictions to variations in mantle viscosity. We show, in contrast to earlier efforts to explore this sensitivity based on the traditional rotation theory, that the datum does not generally have a sensitivity to viscosity that peaks near the base of the mantle.

  11. Using triaxial magnetic fields to create optimal particle composites.

    SciTech Connect

    Martin, James Ellis

    2004-05-01

    The properties of a particle composite can be controlled by organizing the particles into assemblies. The properties of the composite will depend on the structure of the particle assemblies, and for any give property there is some optimal structure. Through simulation and experiment we show that the application of heterodyned triaxial magnetic or electric fields generates structures that optimize the magnetic and dielectric properties of particle composites. We suggest that optimizing these properties optimizes other properties, such as transport properties, and we give as one example of this optimization the magnetostriction of magnetic particle composites formed in a silicone elastomer.

  12. Commissioning of a Soft X-ray Beamline PF-BL-16A with a Variable-Included-Angle Varied-Line-Spacing Grating Monochromator

    SciTech Connect

    Amemiya, Kenta; Toyoshima, Akio; Kikuchi, Takashi; Kosuge, Takashi; Nigorikawa, Kazuyuki; Sumii, Ryohei; Ito, Kenji

    2010-06-23

    The design and commissioning of a new soft X-ray beamline, BL-16A, at the Photon Factory is presented. The beamline consists of a pre-focusing mirror, an entrance slit, a variable-included-angle varied-line-spacing plane grating monochromator, and a post-focusing system as usual, and provides circularly and linearly polarized soft X rays in the energy range 200-1500 eV with an APPLE-II type undulator. The commissioning procedure for the beamline optics is described in detail, especially the check of the focal position for the zero-th order and diffracted X rays.

  13. 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.

  14. 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.

  15. Triaxial magnetic field gradient system for microcoil magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Seeber, D. A.; Hoftiezer, J. H.; Daniel, W. B.; Rutgers, M. A.; Pennington, C. H.

    2000-11-01

    There is a great advantage in signal to noise ratio (S/N) that can be obtained in nuclear magnetic resonance (NMR) experiments on very small samples (having spatial dimensions ˜100 μm or less) if one employs NMR "micro" receiver coils, "microcoils," which are of similarly small dimensions. The gains in S/N could enable magnetic resonance imaging (MRI) microscopy with spatial resolution of ˜1-2 μm, much better than currently available. Such MRI microscopy however requires very strong (>10 T/m), rapidly switchable triaxial magnetic field gradients. Here, we report the design and construction of such a triaxial gradient system, producing gradients substantially greater than 15 T/m in all three directions, x, y, and z (and as high as 50 T/m for the x direction). The gradients are switchable within time ˜10 μs and adequately uniform (within 5% over a volume of [600μm3] for microcoil MRI of small samples.

  16. Models of cuspy triaxial stellar systems - I. Stability and chaoticity

    NASA Astrophysics Data System (ADS)

    Zorzi, A. F.; Muzzio, J. C.

    2012-06-01

    We used the N-body code of Hernquist & Ostriker to build a dozen cuspy (γ≃ 1) triaxial models of stellar systems through dissipationless collapses of initially spherical distributions of 106 particles. We chose four sets of initial conditions that resulted in models morphologically resembling E2, E3, E4 and E5 galaxies, respectively. Within each set, three different seed numbers were selected for the random number generator used to create the initial conditions, so that the three models of each set are statistically equivalent. We checked the stability of our models using the values of their central densities and of their moments of inertia, which turned out to be very constant indeed. The changes of those values were all less than 3 per cent over one Hubble time and, moreover, we show that the most likely cause of those changes are relaxation effects in the numerical code. We computed the six Lyapunov exponents of nearly 5000 orbits in each model in order to recognize regular, partially and fully chaotic orbits. All the models turned out to be highly chaotic, with less than 25 per cent of their orbits being regular. We conclude that it is quite possible to obtain cuspy triaxial stellar models that contain large fractions of chaotic orbits and are highly stable. The difficulty in building such models with the method of Schwarzschild should be attributed to the method itself and not to physical causes.

  17. Design and analysis of miniature tri-axial fluxgate magnetometer

    NASA Astrophysics Data System (ADS)

    Zhi, Menghui; Tang, Liang; Qiao, Donghai

    2017-02-01

    The detection technology of weak magnetic field is widely used in Earth resource survey and geomagnetic navigation. Useful magnetic field information can be obtained by processing and analyzing the measurement data from magnetic sensors. A miniature tri-axial fluxgate magnetometer is proposed in this paper. This miniature tri-axial fluxgate magnetometer with ring-core structure has a dynamic range of the Earth’s field ±65,000 nT, resolution of several nT. It has three independent parts placed in three perpendicular planes for measuring three orthogonal magnetic field components, respectively. A field-programmable gate array (FPGA) is used to generate stimulation signal, analog-to-digital (A/D) convertor control signal, and feedback digital-to-analog (D/A) control signal. Design and analysis details are given to improve the dynamic range, sensitivity, resolution, and linearity. Our prototype was measured and compared with a commercial standard Magson fluxgate magnetometer as a reference. The results show that our miniature fluxgate magnetometer can follow the Magson’s change trend well. When used as a magnetic compass, our prototype only has ± 0.3∘ deviation compared with standard magnetic compass.

  18. 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.

  19. 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.

    1993-01-01

    This paper investigates the unnotched tensile properties of two-dimensional (2D) triaxial braid-reinforced composites both experimentally and analytically. The materials are graphite fibers in an epoxy matrix. Three different reinforcing fiber architectures were considered. 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, 0 deg, 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.

  20. 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.

  1. Triaxiality and Exotic Rotations at High Spins in 134Ce

    DOE PAGES

    Petrache, C. M.; Guo, S.; Ayangeakaa, A. D.; ...

    2016-06-06

    High-spin states in Ce-134 have been investigated using the Cd-116(Ne-22,4n) reaction and the Gammasphere array. The level scheme has been extended to an excitation energy of similar to 30 MeV and spin similar to 54 (h) over bar. 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-Strutinskymore » 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.« less

  2. 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.

  3. Mechanical properties of tuffaceous rocks under triaxial conditions

    SciTech Connect

    Karakouzian, M.; Hudyma, N.

    1994-12-01

    Yucca Mountain has been designated as a potential site for a high level nuclear waste repository. Part of the site characterization program is an investigation of the mechanical properties of, the tuffs which comprise Yucca Mountain. This study tested specimens of TCw tuff in triaxial compression to observe the effects of confining pressure, saturation, strain rate, and anisotropy on the compressive strengths and Young`s Moduli of the specimens. Test results have shown that increasing the confining pressure increased the compressive strength and generally increased the Young`s Modulus. Saturation appears to lower both the compressive strength and Young`s Modulus of the specimens. Increasing strain rates increases the compressive strengths, but lowers the Young`s Modulus values. There appears to be a stiffness anisotropy where the specimens are stiffer perpendicular to the orientation of the lithophysal cavity orientation. Correlations with porosity have shown an increase in porosity generally lowers both the compressive strength and the Young`s Modulus of the specimens. From the triaxial tests, the Mohr -- Coulomb strength parameters have also been determined. A comparison between the strengths and modulus values from this study, values from previous studies and the suggested values reveal that the values computed for this study are generally lower than the previously published data. This discrepancy may be due to sample and specimen differences between the studies.

  4. Unified Formulation for a Triaxial Elastoplastic Constitutive Law for Concrete

    PubMed Central

    Hammoud, Rabah; Boukhili, Rachid; Yahia, Ammar

    2013-01-01

    A constitutive model to describe the triaxial load-response spectrum of plain concrete in both tension and shear was developed. The inelastic phenomena are described using the plastic flow with direction determined by the gradient of the plastic potential. A new plastic potential is introduced and experimentally fitted to ensure better estimate of the load direction. This approach allows to control the inelastic dilatancy in terms of the inelastic deformation of the material. By overlaying the plastic potential on modified Etse and Willam’s yield surface (both defined on the Haigh–Westergaard coordinates), the results showed that the two curves do not undergo similar stress states for a given strength level. It is, therefore, necessary that each surface goes through the current stress state to ensure adequate evaluation of normal vectors. A closed-form solution to accurately predict the triaxial stress state in concrete has been proposed. The predictive capabilities of the proposed model are evaluated by comparing predicted and measured stresses. The proposed model is shown to be accurate in predicting stress state of concrete. PMID:28788328

  5. Chasing triaxiality: Probing structure in the A 110 region via lifetime measurements of 109Ru and 109Tc with fast timing

    NASA Astrophysics Data System (ADS)

    Smith, Mallory K.

    Lifetimes of excited states are one of the most powerful observables for nuclear structure. Lifetimes directly relate to the transition probability between states, which in turn provides information on nuclear collectivity, deformation, band structure and single particle states. These are exactly the type of information needed in the hunt for triaxiality in the nuclear landscape. This long-proposed axially asymmetric deformation has recently been the focus of many experimental and theoretical efforts, and while a handful of triaxial nuclei have been observed, rigid triaxial deformation in the nuclear ground state has not been established. Far from stability, nuclear structure and the onset of deformation evolves rapidly. Reliable structure information is crucial in understanding this shape evolution across isotopic and isobaric chains, and triaxiality has been proposed as the shape-transition mechanism responsible for the behavior seen in rapid transition regions. In particular the A ˜ 110 nuclei exhibit a brisk onset of deformation. Signatures of shape-phase transitions, triaxial deformations, shape coexistence and oblate configurations have been reported within a small window of the nuclear landscape, from both theory studies and experimental measurements. In this thesis, we investigated the behavior of the A=109 beta-decay chain, specifically the ruthenium and palladium isotopes, from the fission of 238U at the Univ. of Jyvaskyla IGISOL facility. Level lifetimes and gamma-ray transitions were measured with a multi-detector array consisting of of 2 HPGe detectors, 2 LaBr scintillators and 1 plastic scintillator. Triple coincidence beta-gamma-gamma events were recorded and used to construct/check level schemes, and extract picosecond-range level lifetimes via the fast-timing method pioneered by H. Mach. Our results include new data for the low energy level schemes of 109Tc, 109Ru and 109 Pd, including the first lifetime measurements in 109Tc, where three excited

  6. 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.

  7. A Multi Material Shell Model for the Mechanical Analysis of Triaxial Braided Composites

    NASA Astrophysics Data System (ADS)

    García-Carpintero, A.; Herráez, M.; Xu, J.; S. Lopes, C.; González, C.

    2017-03-01

    An efficient numerical methodology based on a multi material shell (MMS) approximation is proposed in this paper for the analysis of the mechanical behavior of triaxial braided composites subjected to tensile loads. The model is based on a geometrical description of the textile architecture of the material at the Gauss point level of a standard shell including the corresponding yarn geometrical parameters. The mechanical properties at the yarn level were determined from values reported in the literature or by means of micromechanical homogenization of unidirectional fiber reinforced composites. Simulations were carried out on single representative unit cell subjected to periodic boundary conditions and on multiple cell representative volume elements corresponding to the size of the standard width of a tensile specimen. The numerical results were compared with the stress-strain curves obtained experimentally as well as the damage mechanisms progression during deformation captured using radiographs performed on interrupted tests.

  8. 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

  9. 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

  10. 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

  11. Response of Seismometer with Symmetric Triaxial Sensor Configuration to Complex Ground Motion

    NASA Astrophysics Data System (ADS)

    Graizer, V.

    2007-12-01

    Most instruments used in seismological practice to record ground motion in all directions use three sensors oriented toward North, East and upward. In this standard configuration horizontal and vertical sensors differ in their construction because of gravity acceleration always applied to a vertical sensor. An alternative way of symmetric sensor configuration was first introduced by Galperin (1955) for petroleum exploration. In this arrangement three identical sensors are also positioned orthogonally to each other but are tilted at the same angle of 54.7 degrees to the vertical axis (triaxial system of coordinate balanced on its corner). Records obtained using symmetric configuration must be rotated into an earth referenced X, Y, Z coordinate system. A number of recent seismological instruments (e.g., broadband seismometers Streckeisen STS-2, Trillium of Nanometrics and Cronos of Kinemetrics) are using symmetric sensor configuration. In most of seismological studies it is assumed that rotational (rocking and torsion) components of earthquake ground motion are small enough to be neglected. However, recently examples were shown when rotational components are significant relative to translational components of motions. Response of pendulums installed in standard configuration (vertical and two horizontals) to complex input motion that includes rotations has been studied in a number of publications. We consider the response of pendulums in a symmetric sensor configuration to complex input motions including rotations, and the resultant triaxial system response. Possible implications of using symmetric sensor configuration in strong motion studies are discussed. Considering benefits of equal design of all three sensors in symmetric configuration, and as a result potentially lower cost of the three-component accelerograph, it may be useful for strong motion measurements not requiring high resolution post signal processing. The disadvantage of this configuration is that if

  12. True triaxial strength and deformability of crystalline rocks

    NASA Astrophysics Data System (ADS)

    Chang, Chandong

    A fundamental laboratory study was conducted in the deformation and strength of Westerly granite and KTB amphibolite subjected to true triaxial compressive stress conditions (sigma1 > sigma2 > sigma 3) with a particular attention to sigma2 effect on rock failure process. It was found that sigma2 strongly affects the criteria of strength for these rocks, contrary to the assumption contained in commonly accepted Mohr-type failure criteria. Under true triaxial stress conditions, crystalline rocks fail along a steeply inclined throughgoing shear fracture striking to the sigma2 direction. Stress-induced microcracks also develop mainly parallel to sigma2 direction, as the intermediate stress grows beyond sigma3, localizing along the plane that eventually becomes the throughgoing fracture. A general strength criterion can be expressed in terms of the octahedral shear stress and the mean normal stress acting on the failure plane. In a separate series of tests, failure of KTB amphibolite under borehole wall condition was simulated by leaving one pair of the prismatic specimens faces unjacketed and in direct contact with the confining fluid through which sigma 3 is applied. These tests reveal that brittle fracture occurs at a considerably lower stress level than that in dry amphibolite, and results from the development of a swarm of densely spaced extensile fractures subparallel and adjacent to one of the unjacketed faces. It is inferred that upon dilatancy onset, confining fluid intrudes microcracks, which are predominantly subparallel to the unjacketed faces, and promotes their elongation into throughgoing fractures. A true triaxial strength criterion of the unjacketed amphibolite can be expressed in terms of the octahedral shear stress as a function of the octahedral normal stress. The magnitudes of the maximum horizontal in situ stresses at the KTB hole, Germany, were computed based on the strength criterion of the unjacketed KTB amphibolite together with all the other

  13. 3D controlled electrorotation of conducting tri-axial ellipsoidal nanoparticles

    NASA Astrophysics Data System (ADS)

    Weis Goldstein, Ben; Miloh, Touvia

    2017-05-01

    We present a theoretical study of 3D electrorotation of ideally polarizable (metallic) nano∖micro-orthotropic particles that are freely suspended in an unbounded monovalent symmetric electrolyte. The metallic tri-axial ellipsoidal particle is subjected to three independent uniform AC electric fields acting along the three principal axes of the particle. The analysis of the electrokinetic problem is carried under the Poisson-Nernst-Planck approximation and the standard "weak" field assumption. For simplicity, we consider the electric double layer as thin and the Dukhin number to be small. Both nonlinear phenomena of dielectrophoresis induced by the dipole-moment within the particle and the induced-charge electrophoresis caused by the Coulombic force density within the Debye layer in the solute surrounding the conducting particle are analytically analyzed by linearization, constructing approximate expressions for the total dipolophoresis angular particle motion for various geometries. The analytical expressions thus obtained are valid for an arbitrary tri-axial orthotropic (exhibiting three planes of symmetry) particle, excited by an arbitrary ambient three-dimensional AC electric field of constant amplitude. The present study is general in the sense that by choosing different geometric parameters of the ellipsoidal particle, the corresponding nonlinear electrostatic problem governed by the Robin (mixed-type) boundary condition can be reduced to common nano-shapes including spheres, slender rods (needles), prolate and oblate spheroids, as well as flat disks. Furthermore, by controlling the parameters (amplitudes and phases) of the forcing electric field, one can reduce the present general 3D electrokinetic model to the familiar planar electro-rotation (ROT) and electro-orientation (EOR) cases.

  14. Posture and movement classification: the comparison of tri-axial accelerometer numbers and anatomical placement.

    PubMed

    Fortune, Emma; Lugade, Vipul A; Kaufman, Kenton R

    2014-05-01

    Patient compliance is important when assessing movement, particularly in a free-living environment when patients are asked to don their own accelerometers. Reducing the number of accelerometers could increase patient compliance. The aims of this study were (1) to determine and compare the validity of different accelerometer combinations and placements for a previously developed posture and dynamic movement identification algorithm. Custom-built activity monitors, each containing one tri-axial accelerometer, were placed on the ankles, right thigh, and waist of 12 healthy adults. Subjects performed a protocol in the laboratory including static orientations of standing, sitting, and lying down, and dynamic movements of walking, jogging, transitions between postures, and fidgeting to simulate free-living activity. When only one accelerometer was used, the thigh was found to be the optimal placement to identify both movement and static postures, with a misclassification error of 10%, and demonstrated the greatest accuracy for walking/fidgeting and jogging classification with sensitivities and positive predictive value (PPVs) greater than 93%. When two accelerometers were used, the waist-thigh accelerometers identified movement and static postures with greater accuracy than the thigh-ankle accelerometers (with a misclassification error of 11% compared to 17%). However, the thigh-ankle accelerometers demonstrated the greatest accuracy for walking/ fidgeting and jogging classification with sensitivities and PPVs greater than 93%. Movement can be accurately classified in healthy adults using tri-axial accelerometers placed on one or two of the following sites: waist, thigh, or ankle. Posture and transitions require an accelerometer placed on the waist and an accelerometer placed on the thigh.

  15. Triaxial bulge, thin disc and bar of the Milky Way

    NASA Astrophysics Data System (ADS)

    Picaud, S.

    2004-12-01

    We present here two studies of the inner Milky Way using both the Besançon model of the Galaxy and near infrared star counts. Firstly, we have fitted the density parameters of the triaxial outer bulge and the inner old thin disc with DENIS data at |ℓ|<12° and |b|<4°, and show that the bulge is very oblate, with an angle from the sun-Galactic center direction of ≈10°. Secondly, we have compared Besançon simulations with CAIN data at 15°<ℓ<45° |b|≤ 2°, and show the existence of an in-plane extra density of stars at l≤27°, with a distance from the sun at ≈6 kpc. This extended over-density might correspond to the top end of a bar having a half-length of about 4 kpc and an angle of 45°±9°.

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

    NASA Astrophysics Data System (ADS)

    Statler, Thomas S.

    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.

  17. 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.

  18. Characteristics of dynamic triaxial testing of asphalt mixtures

    NASA Astrophysics Data System (ADS)

    Ulloa Calderon, Alvaro

    Due to the increasing traffic loads and tire pressures, a serious detrimental impact has occurred on flexible pavements in the form of excessive permanent deformation once the critical combination of loading and environmental conditions are reached. This distress, also known as rutting, leads to an increase in road roughness and ultimately jeopardizes the road users' safety. The flow number (FN) simple performance test for asphalt mixtures was one of the final three tests selected for further evaluation from the twenty-four test/material properties initially examined under the NCHRP 9-19 project. Currently, no standard triaxial testing conditions in terms of the magnitude of the deviator and confining stresses have been specified. In addition, a repeated haversine axial compressive load pulse of 0.1 second and a rest period of 0.9 second are commonly used as part of the triaxial testing conditions. The overall objective of this research was to define the loading conditions that created by a moving truck load in the hot mixed asphalt (HMA) layer. The loading conditions were defined in terms of the triaxial stress levels and the corresponding loading time. Dynamic mechanistic analysis with circular stress distribution was used to closely simulate field loading conditions. Extensive mechanistic analyses of three different asphalt pavement structures subjected to moving traffic loads at various speeds and under braking and non-braking conditions were conducted using the 3D-Move model. Prediction equations for estimating the anticipated deviator and confining stresses along with the equivalent deviator stress pulse duration as a function of pavement temperature, vehicle speed, and asphalt mixture's stiffness have been developed. The magnitude of deviator stress, sigmad and confining stress, sigmac, were determined by converting the stress tensor computed in the HMA layer at 2" below pavement surface under a moving 18-wheel truck using the octahedral normal and shear

  19. 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.

  20. Uniaxial and triaxial compression test series on Calico Hills tuff

    NASA Astrophysics Data System (ADS)

    Price, R. H.; Jones, A. K.

    1982-10-01

    Forty-four uniaxial and triaxial compression experiments were performed on samples of the Tuffaceous beds of Calico Hills obtained from drill hole USW-G1 at Yucca Mountain on the Nevada Test Site. Water saturated and room dry test specimens were deformed at nominal strain rates of 0.001,0.00001, 10 to the minus 7th power, s(1), confining pressures of 0.1, 10 and 20 MPa; and room temperature. Resultant unconfined compressive strengths, axial strains to failure, Young's moduli and Poisson's ratios ranged from 14.2 to 42.0 MPa, 0.0037 to 0.0087, 2.52 to 9.72 GPA and 0.17 to 0.37, respectively.

  1. Uniaxial and triaxial compression test series on Calico Hills tuff

    SciTech Connect

    Price, R.H.; Jones, A.K.

    1982-10-01

    Forty-four uniaxial and triaxial compression experiments were performed on samples of the Tuffaceous beds of Calico Hills obtained from drill hole USW-G1 at Yucca Mountain on the Nevada Test Site. Water saturated and room dry test specimens were deformed at nominal strain rates of 10{sup -3}, 10{sup -5} and 10{sup -7} s{sup -1}; confining pressures of 0.1, 10 and 20 MPa; and room temperature. Resultant unconfined compressive strengths, axial strains to failure, Young`s moduli and Poisson`s ratios ranged from 14.2 to 42.0 MPa, 0.0037 to 0.0087, 2.52 to 9.72 GPA and 0.17 to 0.37, respectively.

  2. Nuclear structure and triaxiality with the algebraic collective model

    SciTech Connect

    Caprio, M. A.; Rowe, D. J.; Welsh, T. A.

    2009-01-28

    A tractable scheme for numerical diagonalization of the Bohr Hamiltonian, based on SU(1,1)xSO(5) algebraic methods, has recently been proposed. The direct product basis obtained from an optimally chosen set of SU(1,1){beta} wave functions and the SO(5) spherical harmonics {psi}{sub v{alpha}}{sub LM}({gamma},{omega}) provides an exceedingly efficient basis for numerical solution, as compared to conventional diagonalization in a five-dimensional oscillator basis. In this contribution, the status of the SU(1,1)xSO(5) algebraic collective model is summarized and applications are presented. In particular, the transition from axially symmetric to triaxial structure is explored.

  3. LINE-1 ORF1 Protein Localizes in Stress Granules with Other RNA-Binding Proteins, Including Components of RNA Interference RNA-Induced Silencing Complex▿ †

    PubMed Central

    Goodier, John L.; Zhang, Lili; Vetter, Melissa R.; Kazazian, Haig H.

    2007-01-01

    LINE-1 retrotransposons constitute one-fifth of human DNA and have helped shape our genome. A full-length L1 encodes a 40-kDa RNA-binding protein (ORF1p) and a 150-kDa protein (ORF2p) with endonuclease and reverse transcriptase activities. ORF1p is distinctive in forming large cytoplasmic foci, which we identified as cytoplasmic stress granules. A phylogenetically conserved central region of the protein is critical for wild-type localization and retrotransposition. Yeast two-hybrid screens revealed several RNA-binding proteins that coimmunoprecipitate with ORF1p and colocalize with ORF1p in foci. Two of these proteins, YB-1 and hnRNPA1, were previously reported in stress granules. We identified additional proteins associated with stress granules, including DNA-binding protein A, 9G8, and plasminogen activator inhibitor RNA-binding protein 1 (PAI-RBP1). PAI-RBP1 is a homolog of VIG, a part of the Drosophila melanogaster RNA-induced silencing complex (RISC). Other RISC components, including Ago2 and FMRP, also colocalize with PAI-RBP1 and ORF1p. We suggest that targeting ORF1p, and possibly the L1 RNP, to stress granules is a mechanism for controlling retrotransposition and its associated genetic and cellular damage. PMID:17562864

  4. Validation of the Geant4 Monte Carlo package for X-ray fluorescence spectroscopy in triaxial geometry

    NASA Astrophysics Data System (ADS)

    Amaro, Pedro; Santos, José Paulo; Samouco, Ana; Adão, Ricardo; Martins, Luís Souto; Weber, Sebastian; Tashenov, Stanislav; Carvalho, Maria Luisa; Pessanha, Sofia

    2017-04-01

    In this study, we investigated the potential of the Geant4 Monte Carlo simulation package for retrieving accurate elemental concentrations from energy dispersive X-ray fluorescence spectra. For this purpose, we implemented a Geant4 code that simulates an energy dispersive X-ray fluorescence spectrometer in a triaxial geometry. In parallel, we also performed measurements in a spectrometer with the same geometry, for validation of the present code. This spectrometer allows low limits of detection and permits an effective comparison of elemental concentrations down to tens of part-per-million. Several standard reference materials of both light, medium and heavy matrices were employed in order to attest the validity of simulations for several values of averaged atomic number. We observed good agreement of better than 25% for most fluorescence lines of interest, and for all materials. Discrepancies were observed at the multiple Compton scattering tail. We thus concluded from this experimental and theoretical study that the present Geant4 code can be incorporated in a quantitative method for the determination of trace elements in a triaxial-type spectrometer.

  5. Stress-Dilatancy for Soils. Part II: Experimental Validation for Triaxial Tests

    NASA Astrophysics Data System (ADS)

    Szypcio, Zenon

    2016-12-01

    Different forms of the stress-dilatancy relations obtained based on the frictional theory for the triaxial condition are presented. The analysed test data show that the shear resistance of many soils is purely frictional. The angle Φ0 represents the resistance of the soil as a combined effect of sliding and particle rolling on the macro-scale during shear at the critical frictional state. The stress-plastic dilatancy relations differ not only for triaxial compression and extension but also for drained and undrained conditions. The experiment investigated shows the correctness of the frictional state theory in the triaxial condition.

  6. 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.

  7. Triaxial testing system for pressure core analysis using image processing technique

    NASA Astrophysics Data System (ADS)

    Yoneda, J.; Masui, A.; Tenma, N.; Nagao, J.

    2013-11-01

    In this study, a newly developed innovative triaxial testing system to investigate strength, deformation behavior, and/or permeability of gas hydrate bearing-sediments in deep sea is described. Transport of the pressure core from the storage chamber to the interior of the sealing sleeve of a triaxial cell without depressurization was achieved. An image processing technique was used to capture the motion and local deformation of a specimen in a transparent acrylic triaxial pressure cell and digital photographs were obtained at each strain level during the compression test. The material strength was successfully measured and the failure mode was evaluated under high confining and pore water pressures.

  8. Fabrication of Tri-axially Oriented RE-Ba-Cu-O Ceramics by Magnetic Alignment

    NASA Astrophysics Data System (ADS)

    Yamaki, M.; Furuta, M.; Doi, T.; Shimoyama, J.; Horii, S.

    Magnetic alignment is a new crystal alignment process which enables tri-axial orientation without epitaxial growth at room temperature. In order to investigate the effectiveness of this magnetic tri-axial alignment process, we attempted to fabricate tri-axially oriented ErBa2Cu4O8 (Er124) ceramics by a slip-casting technique under two different modulated rotation magnetic fields (MRFs); uni-directional rotation type and oscillation type. For improvement of the degrees of tri-axial orientation in the Er124 green compacts slip-casted under MRFs, appropriate choice of sample-rotation method, magnetic field condition, control of mean diameter of source powders, and viscosity of slurry was found to be important in the case of MRFs induced by the sample-rotation. At the current stage, the degree of inplane orientation with ∼10̊ in Er124 was achieved.

  9. 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.

  10. Strength and deformation behaviors of veined marble specimens after vacuum heat treatment under conventional triaxial compression

    NASA Astrophysics Data System (ADS)

    Su, Haijian; Jing, Hongwen; Yin, Qian; Yu, Liyuan; Wang, Yingchao; Wu, Xingjie

    2017-03-01

    The mechanical behaviors of rocks affected by high temperature and stress are generally believed to be significant for the stability of certain projects involving rocks, such as nuclear waste storage and geothermal resource exploitation. In this paper, veined marble specimens were treated to high temperature treatment and then used in conventional triaxial compression tests to investigate the effect of temperature, confining pressure, and vein angle on strength and deformation behaviors. The results show that the strength and deformation parameters of the veined marble specimens changed with the temperature, presenting a critical temperature of 600°C. The triaxial compression strength of a horizontal vein (β = 90°) is obviously larger than that of a vertical vein (β = 0°). The triaxial compression strength, elasticity modulus, and secant modulus have an approximately linear relation to the confining pressure. Finally, Mohr-Coulomb and Hoek-Brown criteria were respectively used to analyze the effect of confining pressure on triaxial compression strength.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  12. Pore-water extraction from unsaturated tuff by triaxial and one-dimensional compression methods, Nevada Test Site, Nevada

    USGS Publications Warehouse

    Mower, Timothy E.; Higgins, Jerry D.; Yang, In C.; Peters, Charles A.

    1994-01-01

    Study of the hydrologic system at Yucca Mountain, Nevada, requires the extraction of pore-water samples from welded and nonwelded, unsaturated tuffs. Two compression methods (triaxial compression and one-dimensional compression) were examined to develop a repeatable extraction technique and to investigate the effects of the extraction method on the original pore-fluid composition. A commercially available triaxial cell was modified to collect pore water expelled from tuff cores. The triaxial cell applied a maximum axial stress of 193 MPa and a maximum confining stress of 68 MPa. Results obtained from triaxial compression testing indicated that pore-water samples could be obtained from nonwelded tuff cores that had initial moisture contents as small as 13 percent (by weight of dry soil). Injection of nitrogen gas while the test core was held at the maximum axial stress caused expulsion of additional pore water and reduced the required initial moisture content from 13 to 11 percent. Experimental calculations, together with experience gained from testing moderately welded tuff cores, indicated that the triaxial cell used in this study could not apply adequate axial or confining stress to expel pore water from cores of densely welded tuffs. This concern led to the design, fabrication, and testing of a one-dimensional compression cell. The one-dimensional compression cell used in this study was constructed from hardened 4340-alloy and nickel-alloy steels and could apply a maximum axial stress of 552 MPa. The major components of the device include a corpus ring and sample sleeve to confine the sample, a piston and base platen to apply axial load, and drainage plates to transmit expelled water from the test core out of the cell. One-dimensional compression extracted pore water from nonwelded tuff cores that had initial moisture contents as small as 7.6 percent; pore water was expelled from densely welded tuff cores that had initial moisture contents as small as 7

  13. True Triaxial Failure of Granite: Implications for Deep Borehole Waste Disposal

    NASA Astrophysics Data System (ADS)

    Williams, M.; Ingraham, M. D.; Cheung, C.; Haimson, B. C.

    2016-12-01

    A series of tests have been completed to determine the failure of Sierra White Granite under a range of true triaxial stress conditions ranging from axisymmetric compression to axisymmetric extension. Tests were performed under constant mean stress conditions. Results show a significant difference in failure due to the intermediate principal stress. Borehole breakout, a significant issue for deep borehole disposal, occurs in line with the least principal stress, which in the United States at great depth is almost certainly a horizontal stress. This means that any attempt to dispose of waste in deep boreholes will have to overcome this phenomenon. This work seeks to determine the full 3D failure surface for granite such that it can be applied to determining the likelihood of borehole breakout occurring under different stress conditions. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  14. 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.

  15. 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

  16. 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.

  17. Senescence-associated β-galactosidase staining in fish cell lines and primary cultures from several tissues and species, including rainbow trout coelomic fluid and milt.

    PubMed

    Vo, Nguyen T K; Mikhaeil, Michael S; Lee, Lucy E J; Pham, Phuc H; Bols, Niels C

    2015-04-01

    Cell lines and primary cultures from several teleost tissues and species were stained for senescence-associated β-galactosidase (SA β-Gal), revealing four general outcomes. (1) For long-standing fish cell lines that can be considered immortal, little or no SA β-Gal staining was observed, regardless of the culture conditions. (2) For a new walleye cell line from the bulbus arteriosus (WEBA), most cells stained for SA β-Gal even after 40 passages. This suggested that high SA β-Gal activity was a unique property of WEBA, perhaps reflecting their endothelial character, rather than cellular senescence. (3) For cell lines developed from the walleye caudal fin and from somatic cells in rainbow trout coelomic fluid, no SA β-Gal staining was observed in the earliest cultures to over 70 passages later. This suggested that cells from these anatomical sites do not undergo senescence in vitro. (4) By contrast, for cell lines developed from the walleye brain and from somatic cells in rainbow trout milt, most cells in the early-stage cultures stained for SA β-Gal, but as these were developed into cell lines, SA β-Gal-negative cells became dominant. This suggested that if cellular senescence occurred in vitro, this happened early in these cultures and subsequently a few SA β-Gal-negative cells went onto to form the cell line. Overall, the presence of SA β-Gal-positive cells in cultures could be interpreted in several ways, whereas their absence predicted that in these cultures, cells would proliferate indefinitely.

  18. Permeability Evolution of Granite Gneiss During Triaxial Creep Tests

    NASA Astrophysics Data System (ADS)

    Liu, L.; Xu, W. Y.; Wang, H. L.; Wang, W.; Wang, R. B.

    2016-09-01

    Permeability is an important factor for seepage analysis of rock material, and a key factor in ensuring the safety of underground works. In this study, the permeability evolution of granite gneiss during triaxial creep tests was investigated. In the context of an underground oil storage cavern in China, a series of hydro-mechanical coupling creep tests were conducted on rock cores of granite gneiss at three different pore pressures to reveal the effect of pore pressure on the permeability evolution and to investigate the correlation between the permeability and volumetric strain during the creep process. During the creep tests, the permeability decreases in the initial loading phase. At all deviatoric stress levels, the permeability remains stable in the steady creep stage and increases rapidly in the accelerated creep stage. Based on the test data, the initial permeability, steady permeability and peak permeability at various stress levels are defined. The effect of pore pressure on the permeability is captured by a linear model. In addition, the relationship between permeability and volumetric strain can be described as a process divided into three phases, with different functions in each phase.

  19. Dynamic triaxial compression experiments on Cor-Tuf specimens

    NASA Astrophysics Data System (ADS)

    Mondal, Alex B.

    A set of dynamic triaxial compression experiments at 50 MPa, 100 MPa, and 200 MPa confinement have been conducted with a modified Kolsky bar on cylindrical ultra high strength concrete Cor-Tuf specimens of diameter 19 mm and length of 12.7 mm. The experiment is composed of a hydrostatic phase which occurs at a quasi-static strain rate followed by a dynamic shear phase which occurs at a high strain rate. A set of 28 experiments were conducted at strain rates of 100 s-1 and 200 s-1. The experiments show that the fracture strength of the material increases under the test conditions. The specimens showed higher strength in the dynamic confined experiments than both the quasi-static TXC tests and the unconfined dynamic tests. The strength increase was attributed to specimen size difference and not a strain rate or confinement effect. Although the trend towards brittle ductile transition is observed the specimens were not tested in a high enough confinement for the phase change to occur.

  20. Micromechanics of Brittle Creep Under Triaxial Loading Conditions

    NASA Astrophysics Data System (ADS)

    Meredith, P. G.; Brantut, N.; Baud, P.; Heap, M. J.

    2011-12-01

    In the upper crust, the chemical influence of pore water promotes time-dependent brittle deformation through sub-critical crack growth. Sub-critical crack growth allows rocks to deform and fail (i) at stresses far below their short-term failure strength, and (ii) even at constant applied stress ("brittle creep"). Here we provide a micromechanical model and experimental results describing time-dependent brittle creep of water-saturated granite under triaxial stress conditions. Macroscopic brittle creep is modeled on the basis of microcrack extension under compressive stresses due to sub-critical crack growth. The incremental strains due to the growth of microcracks in compression are derived from the sliding wing-crack model of Ashby and Sammis (1990). Crack length evolution is computed from Charles' law. The macroscopic strain and strain rates are then computed from the change in energy potential due to microcrack growth. They are non-linear, and compare well with complementary experimental results obtained on granite samples. Primary creep (decelerating strain) corresponds to decreasing crack growth rate , due to an initial decrease in stress intensity factor with increasing crack length in compression. Tertiary creep (accelerating strain as failure is approached) corresponds to an increase in crack growth rate due to crack interactions. Secondary creep with apparently constant strain rate arises as merely an inflexion between the two end-member phases.

  1. 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.

  2. Predictive value of VEGF gene polymorphisms for metastatic colorectal cancer patients receiving first-line treatment including fluorouracil, irinotecan, and bevacizumab.

    PubMed

    Formica, Vincenzo; Palmirotta, Raffaele; Del Monte, Girolamo; Savonarola, Annalisa; Ludovici, Giorgia; De Marchis, Maria Laura; Grenga, Italia; Schirru, Michele; Guadagni, Fiorella; Roselli, Mario

    2011-02-01

    The aim of this study is to evaluate the influence of germline vascular endothelial growth factor (VEGF) gene polymorphisms (VGPs) on the efficacy of the anti-VEGF antibody bevacizumab (Bev) in metastatic colorectal cancer (MCRC) patients. Forty MCRC patients eligible for a first-line therapy were enrolled in this prospective trial and treated with FOLinate/Fluorouracil/Irinotecan (FOLFIRI) + Bev (male/female = 22:18, age (median) = 61 years). Eight VGPs within the promoter/5'UTR region were evaluated in patient blood samples. Primary endpoint was association between VGPs and median progression-free survival (mPFS). Overall radiological response rate (ORR), overall survival (OS), and toxicity were assessed as secondary outcomes. VGPs -2578, -1512, -1451, -1411, and -460 were in complete linkage disequilibrium and therefore analyzed as haplotype (two variants: Haplo1: A-18 bp insertion-T-4G-C and Haplo2: C-18 bp deletion-C-5G-T, respectively). Seventeen patients Haplo2/Haplo2 had significantly shorter mPFS compared to 23 patients Haplo1/Haplo1 or Haplo1/Haplo2 (mPFS, 9 vs. 15.4 months, respectively, p = 0.02; hazard ratio (HR), 2.64). Also, VGPs -152 (G/G vs. G/A + A/A) and -1154 (G/G vs. G/A + A/A) were significantly associated with PFS (mPFS, 8.9 vs. 15.4 months, p = 0.007; HR, 3.53 and 9.8 vs. 16 months, p = 0.03, HR, 2.32, respectively). In the multivariate analysis including also biochemical variables known to influence prognosis, VGP -1154 retained an independent predictive value for mPFS (G/G over G/A + A/A = HR, 4.43; p = 0.02). With regard to ORR, only VGP -634 was significantly associated with response (G/G vs. G/C + C/C = 64% vs. 14%, p = 0.03). No significant influence on OS and toxicity by the investigated VGPs was observed. Although these data need to be confirmed in larger trials, investigation of germline VGPs may help identify patients who are more sensitive to anti-VEGF agents.

  3. Statistical Characterization of the Mechanical Parameters of Intact Rock Under Triaxial Compression: An Experimental Proof of the Jinping Marble

    NASA Astrophysics Data System (ADS)

    Jiang, Quan; Zhong, Shan; Cui, Jie; Feng, Xia-Ting; Song, Leibo

    2016-12-01

    We investigated the statistical characteristics and probability distribution of the mechanical parameters of natural rock using triaxial compression tests. Twenty cores of Jinping marble were tested under each different levels of confining stress (i.e., 5, 10, 20, 30, and 40 MPa). From these full stress-strain data, we summarized the numerical characteristics and determined the probability distribution form of several important mechanical parameters, including deformational parameters, characteristic strength, characteristic strains, and failure angle. The statistical proofs relating to the mechanical parameters of rock presented new information about the marble's probabilistic distribution characteristics. The normal and log-normal distributions were appropriate for describing random strengths of rock; the coefficients of variation of the peak strengths had no relationship to the confining stress; the only acceptable random distribution for both Young's elastic modulus and Poisson's ratio was the log-normal function; and the cohesive strength had a different probability distribution pattern than the frictional angle. The triaxial tests and statistical analysis also provided experimental evidence for deciding the minimum reliable number of experimental sample and for picking appropriate parameter distributions to use in reliability calculations for rock engineering.

  4. Burial and seed survival in Brassica napus subsp. oleifera and Sinapis arvensis including a comparison of transgenic and non-transgenic lines of the crop.

    PubMed Central

    Hails, R S; Rees, M; Kohn, D D; Crawley, M J

    1997-01-01

    The creation of transgenic plants through genetic engineering has focused interest on how the fitness of a plant species may be altered by small changes in its genome. This study concentrates on a key component of fitness: persistence of seeds overwinter. Seeds of three lines of oilseed rape (Brassica napus subsp. oleifera DC Metzger) and of charlock (Sinapis arvensis L.) were buried in nylon mesh bags at two depths in four habitats in each of three geographically separated sites: Cornwall, Berkshire and Sutherland. Seeds were recovered after 12 and 24 months. Charlock exhibited much greater seed survival (average 60% surviving the first year and 32.5% surviving the second year) than oilseed rape (1.5% surviving the first year and 0.2% surviving the second) at all sites. Charlock showed higher survival at 15 cm burial than 2 cm burial at certain sites, but oilseed rape showed no depth effect. Different genetic lines of oilseed rape displayed different rates of seed survival; non-transgenic rape showed greater survival (2%) than the two transgenic lines, one developed for tolerance to the antibiotic kanamycin (0.3%) and one for tolerance to both kanamycin and the herbicide glufosinate (0.25%). The absolute and relative performances of the different genetic lines of oilseed rape were context specific, illustrating the need to test hypotheses in a wide range of ecological settings. PMID:9061957

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

    DOE PAGES

    Zhang, C. L.; Bhat, G. H.; Nazarewicz, W.; ...

    2015-09-10

    Here, 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. The purpose of this study is 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-richmore » 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. As a result, our self-consistent DFT calculations predict triaxial ground-state deformations in 106,108Mo and 108,110,112Ru and reproduce the observed low-frequency behavior of moments of inertia. As the rotational frequency increases, a negative-gamma 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. Lastly, the structure of neutron-rich even-even nuclei around Ru-110 is consistent with triaxial shape deformations. Our DFT and TPSM frameworks provide a consistent and complementary description of experimental data.« less

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

    SciTech Connect

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

    2015-09-10

    Here, 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. The purpose of this study is 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. As a result, our self-consistent DFT calculations predict triaxial ground-state deformations in 106,108Mo and 108,110,112Ru and reproduce the observed low-frequency behavior of moments of inertia. As the rotational frequency increases, a negative-gamma 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. Lastly, the structure of neutron-rich even-even nuclei around Ru-110 is consistent with triaxial shape deformations. Our DFT and TPSM frameworks provide a consistent and complementary description of experimental data.

  7. 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

  8. New Line Lists Including Intensities for the {C_2} Swan System (d^3Π{_g}-a^3Π{_u}), {C_2} Singlet Systems and Rovibrational Transitions Within the NH X^3Σ{^-} Ground State.

    NASA Astrophysics Data System (ADS)

    Brooke, J. S. A.; Bernath, P. F.; Western, C. M.; Schmidt, T. W.; Bacskay, G. B.; Hemert, M. C. Van; Groenenboom, G. C.

    2013-06-01

    Line lists including both positions and absolute intensities are required by those who wish to calculate abundances from spectroscopic observations. New line lists for the diatomic molecules {C_2} and NH are presented. Line strengths for the {C_2} Swan system (d^3Π{_g}-a^3Π{_u}) have been calculated for vibrational bands with v'=0-10 and v''=0-9, and J values up to J=34-96, based on previous observations in 36 vibrational bands. Line positions from several sources were combined with the results from recent deperturbation studies of the v'=4 and v'=6 levels, to provide updated molecular constants. The line strengths are based on a recent ab initio calculation of the transition dipole moment function. Einstein A coefficients and f-values were also calculated for the vibrational bands of the Swan system. A line list has been made available, including observed and calculated line positions, Einstein A coefficients and oscillator strengths (f-values). This list will be useful for astronomers, combustion scientists and materials scientists who utilize {C_2} Swan spectra. Similar work is being carried out for a number of singlet systems of {C_2}, in which a single global fit of positions will be performed and intensities calculated. For NH, a line list is being created for the infrared transitions within the X^3Σ{^-} ground state, including previous observations of rotational lines within v=0-2, and rovibrational lines of the Δv=1 sequence up to v'=6. The intensity calculations use a recently calculated dipole moment function which has been used to calculate the lifetime of the v=1 level, but was unpublished. A line list like that for the {C_2} Swan system will be made available, which will be useful for astronomers investigating NH and nitrogen abundance in cool objects.

  9. Models of cuspy triaxial stellar systems - II. Regular orbits

    NASA Astrophysics Data System (ADS)

    Muzzio, J. C.; Navone, H. D.; Zorzi, A. F.

    2013-02-01

    In the first paper of this series we used the N-body method to build a dozen cuspy (γ ≃ 1) triaxial models of stellar systems, and we showed that they were highly stable over time intervals of the order of a Hubble time, even though they had very large fractions of chaotic orbits (more than 85 per cent in some cases). The models were grouped in four sets, each one comprising models morphologically resembling E2, E3, E4 and E5 galaxies, respectively. The three models within each set, although different, had the same global properties and were statistically equivalent. In the present paper we use frequency analysis to classify the regular orbits of those models. The bulk of those orbits are short-axis tubes, with a significant fraction of long-axis tubes (LATs) in the E2 models that decreases in the E3 and E4 models to become negligibly small in the E5 models. Most of the LATs in the E2 and E3 models are outer LATs, but the situation reverses in the E4 and E5 models where the few LATs are mainly inner LATs. As could be expected for cuspy models, most of the boxes are resonant orbits, i.e. boxlets. Nevertheless, only the (x, y) fishes of models E3 and E4 amount to about 10 per cent of the regular orbits, with most of the fractions of the other boxlets being of the order of 1 per cent or less.

  10. Tidal spin down rates of homogeneous triaxial viscoelastic bodies

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

    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 semimajor 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 0.8, like Haumea, has orbital semimajor 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 per cent 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 semimajor axis.

  11. On the photogravitational R4BP when the third primary is a triaxial rigid body

    NASA Astrophysics Data System (ADS)

    Asique, Md Chand; Prasad, Umakant; Hassan, M. R.; Suraj, Md Sanam

    2016-12-01

    The present paper deals with the photogravitational restricted four-body problem, when the third primary is placed at the triangular libration point of the restricted three-body problem is a triaxial rigid body. The third primary m3 is not influencing the motion of the dominating primaries m1 and m2. We have studied the motion of m4, moving under the influence of the three primaries mi, i=1,2,3, but the motion of the primaries is not being influenced by infinitesimal mass m4. The aim of this study is to find the locations of equilibrium points and discuss their stability. We have obtained six non-collinear equilibrium points near the third body when the third body is a triaxial rigid body and a source of radiation. There exist at most ten non-collinear equilibrium points in total for this problem. However, the number of equilibrium points depends on the triaxiality parameters. Further, we have drawn the zero velocity surfaces to determine the possible allowed boundary regions. The stability of non-collinear equilibrium points for different mass parameters, radiation parameters and triaxiality of the third body is also studied. The stability regions of the equilibrium points were expanded due to the triaxiality of the third body and various values of the radiation parameter q.

  12. 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).

  13. 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

    2016-11-01

    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.

  14. Potential Prophylactic Properties of Apple and Characterization of Potent Bioactive from cv. "Granny Smith" Displaying Strong Antimutagenicity in Models Including Human Lymphoblast TK6(+/-) Cell Line.

    PubMed

    Saxena, Sudhanshu; Verma, Jyoti; Gautam, Satyendra

    2016-02-01

    Potential prophylactic attributes in terms of antimutagenicity, antioxidant, and radioprotective properties were evaluated for 8 common apple cultivars namely "Fuji," "Golden Delicious," "Granny Smith," "Ambri Kashmiri," "Kinnaur," "Red Delicious," "Royal Gala," and "Shimla," where cultivar based significant variation was observed. Cv. "Granny Smith" displayed significantly higher and broad spectrum antimutagenicity in Escherichia coli rpoB based rifampicin resistance (Rif(R) ) assay, whereas, "Ambri Kashmiri," "Royal Gala," and "Shimla" showed lower antimutagenicity. Cultivars "Ambri Kashmiri," "Kinnaur," and "Red Delicious" exhibited strong antioxidant activity than cv. "Granny Smith" as assayed by radical scavenging, reducing potential and radioprotective property assays. The antioxidant and radioprotective properties were found to be better correlated than antimutagenicity. Suppression of error-prone DNA repair pathway (such as E. coli SOS response) was found to be one of the possible mechanisms contributing to its antimutagenicity. Phenolic extract of "Granny Smithˮ showing higher antimutagenicity was HPLC purified and the bioactive fraction (tR 35.4 min) contributing maximally (∼80%) to the observed antimutagenicity was identified as procyanidin dimer (PD) by ESI-MS/MS. The above observed antimutagenicity in bacterial assay system was well reproduced in Thymidine Kinase Mutation (TKM) assay performed using human lymphoblast cell line (TK6(+/-) ) cell line making the findings more prophylactically relevant. © 2016 Institute of Food Technologists®

  15. An Atypical Human Induced Pluripotent Stem Cell Line With a Complex, Stable, and Balanced Genomic Rearrangement Including a Large De Novo 1q Uniparental Disomy

    PubMed Central

    Steichen, Clara; Maluenda, Jérôme; Tosca, Lucie; Luce, Eléanor; Pineau, Dominique; Dianat, Noushin; Hannoun, Zara; Tachdjian, Gérard; Melki, Judith

    2015-01-01

    Human induced pluripotent stem cells (hiPSCs) hold great promise for cell therapy through their use as vital tools for regenerative and personalized medicine. However, the genomic integrity of hiPSCs still raises some concern and is one of the barriers limiting their use in clinical applications. Numerous articles have reported the occurrence of aneuploidies, copy number variations, or single point mutations in hiPSCs, and nonintegrative reprogramming strategies have been developed to minimize the impact of the reprogramming process on the hiPSC genome. Here, we report the characterization of an hiPSC line generated by daily transfections of modified messenger RNAs, displaying several genomic abnormalities. Karyotype analysis showed a complex genomic rearrangement, which remained stable during long-term culture. Fluorescent in situ hybridization analyses were performed on the hiPSC line showing that this karyotype is balanced. Interestingly, single-nucleotide polymorphism analysis revealed the presence of a large 1q region of uniparental disomy (UPD), demonstrating for the first time that UPD can occur in a noncompensatory context during nonintegrative reprogramming of normal fibroblasts. PMID:25650439

  16. An atypical human induced pluripotent stem cell line with a complex, stable, and balanced genomic rearrangement including a large de novo 1q uniparental disomy.

    PubMed

    Steichen, Clara; Maluenda, Jérôme; Tosca, Lucie; Luce, Eléanor; Pineau, Dominique; Dianat, Noushin; Hannoun, Zara; Tachdjian, Gérard; Melki, Judith; Dubart-Kupperschmitt, Anne

    2015-03-01

    Human induced pluripotent stem cells (hiPSCs) hold great promise for cell therapy through their use as vital tools for regenerative and personalized medicine. However, the genomic integrity of hiPSCs still raises some concern and is one of the barriers limiting their use in clinical applications. Numerous articles have reported the occurrence of aneuploidies, copy number variations, or single point mutations in hiPSCs, and nonintegrative reprogramming strategies have been developed to minimize the impact of the reprogramming process on the hiPSC genome. Here, we report the characterization of an hiPSC line generated by daily transfections of modified messenger RNAs, displaying several genomic abnormalities. Karyotype analysis showed a complex genomic rearrangement, which remained stable during long-term culture. Fluorescent in situ hybridization analyses were performed on the hiPSC line showing that this karyotype is balanced. Interestingly, single-nucleotide polymorphism analysis revealed the presence of a large 1q region of uniparental disomy (UPD), demonstrating for the first time that UPD can occur in a noncompensatory context during nonintegrative reprogramming of normal fibroblasts. ©AlphaMed Press.

  17. Chiral bands for a quasi-proton and quasi-neutron coupled with a triaxial rotor

    NASA Astrophysics Data System (ADS)

    Zhang, S. Q.; Qi, B.; Wang, S. Y.; Meng, J.

    2007-04-01

    A particle rotor model (PRM) with a quasi-proton and a quasi-neutron coupled with a triaxial rotor is developed and applied to study chiral doublet bands with configurations of an h11/2 proton and an h11/2 quasi-neutron. With pairing treated by the BCS approximation, the present quasiparticle PRM is aimed at simulating one proton and many neutron holes coupled with a triaxial rotor. After a detailed analysis of the angular momentum orientations, energy separation between the partner bands, and behavior of electromagnetic transitions, for the first time we find aplanar rotation or equivalently chiral geometry beyond the usual one proton and one neutron hole coupled with a triaxial rotor.

  18. Control of a line of E. tenella, partly resistant to monensin, by including toltrazuril discontinuously in the drinking water of chickens.

    PubMed

    Chapman, H D

    1987-01-01

    Discontinuous medication with toltrazuril, given in the drinking water at a concentration of 50 ppm, was effective in controlling infection resulting from repeated inoculation of oocysts of a line of E. tenella partly resistant to monensin. Treatment was very effective when the drug was given for periods of 3 days, on two or three occasions at weekly intervals. Monensin, at a concentration of 120 ppm, given continuously in the feed was only partially effective. Following treatment with toltrazuril, birds inoculated with high doses of oocysts were immune to subsequent challenge. It is suggested that discontinuous medication with toltrazuril in the drinking water might provide an alternative to the current practice of incorporating drugs continuously in the feed.

  19. Comparison of the STI NIPIP tracking dynamics identification with the on-line Fourier analyzer DFA results including a time varying case

    NASA Technical Reports Server (NTRS)

    Jex, H. R.; Hanson, G.

    1986-01-01

    The Non-Intrusive Pilot Identification Procedure (NIPIP) recently developed at STI and described at the 1981 Annual Manual was used to identify operators who were compensatory tracking a sub-critical-instability task. NIPIP uses a time domain least squares procedure converting to frequency domain coefficients. The forcing function was a sum of sinusoids supplied by the STI Mark II Describing Function Analyzer, which computes on-line Fourier coefficients of the operator's error/input describing function. The resulting open-loop and operator dynamics computed by each procedure are compared, and they are shown to be reasonably close when there is reasonable power in the error signal at the measurement frequencies. A special run was made in which the operator abruptly reduced gain within 1 sec, and the ability of the NIPIP to identify this step time variation in the operator is illustrated.

  20. Failure of Castlegate Sandstone under True Triaxial Loading

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    Understanding the stress conditions that cause deformation bands to form can provide insight into the geologic processes in a given location. In particular, understanding the relationship of the intermediate principal stress with respect to maximum and minimum compression when bands form, could provide useful information about the intermediate principal stress in field settings. Therefore, a series of tests were performed to investigate the effect of the intermediate principal stress on the mechanical response and failure of Castlegate sandstone under true triaxial states of stress. Constant mean stress tests were run at five different stress states ranging from: 1) intermediate principal stress equal to minimum compression to 2) intermediate principal stress equal to maximum compression. Failure occurred either through deformation band formation or apparent bulk compaction. Specimens that formed a deformation band experienced a stress drop at band formation. For a given level of intermediate principal stress, the peak stress increases with increasing mean stress. Additionally, as intermediate principal stress increases, the peak stress decreases for a given mean stress. Acoustic emissions (AE) recorded during testing were used to locate failure events in three-dimensional space within the sample. This allowed for more detailed investigation of the formation and propagation of the band(s) within the specimen. In specimens that appear to have undergone bulk compaction, AE events were randomly distributed throughout the sample. For specimens with bands, the band angles were measured as the angle between the maximum principal stress direction and the normal to the band that formed. Band angles tend to increase with increasing intermediate principal stress, and decrease with increasing mean stress. Results from the AE data shows that the band angle evolves during testing and the band that is expressed on the surface of the specimen at the conclusion of testing is not

  1. Response of Triaxial State of Stress to Creep Rupture Life and Ductility of 316 LN Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Goyal, Sunil; Laha, K.; Bhaduri, A. K.

    2017-02-01

    In the present investigation, the effect of triaxial state of stress on creep rupture life and ductility of 316 LN stainless steel has been assessed. The creep tests were carried out on both smooth and notched specimens of the steel at 873 K in the stress range of 270-340 MPa. The notched specimens had root radius ranging from 0.83 mm to 5 mm. The detailed finite element analysis has been carried out to assess the triaxial state of stress across the notch incorporating Norton's law as creep deformation governing mechanism. The creep rupture life of the steel increased in presence of triaxial stresses and extent of which was more at lower net applied stresses and higher triaxiality (sharper notch). The reduction in effective stress in presence of notch resulted in higher creep rupture life of the steel under triaxial stresses. The fracture surfaces revealed mixed mode failure consisting of dimple ductile and intergranular creep cavitation for all testing conditions, however, extent of cavitation was higher for relatively higher triaxialities and lower net applied stresses. The creep ductility of the steel was found to decrease drastically under triaxial state of stress. The triaxial rupture life and creep ductility of the steel have been assessed based on different models on incorporating different components of stresses at the skeletal point.

  2. Response of Triaxial State of Stress to Creep Rupture Life and Ductility of 316 LN Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Goyal, Sunil; Laha, K.; Bhaduri, A. K.

    2016-12-01

    In the present investigation, the effect of triaxial state of stress on creep rupture life and ductility of 316 LN stainless steel has been assessed. The creep tests were carried out on both smooth and notched specimens of the steel at 873 K in the stress range of 270-340 MPa. The notched specimens had root radius ranging from 0.83 mm to 5 mm. The detailed finite element analysis has been carried out to assess the triaxial state of stress across the notch incorporating Norton's law as creep deformation governing mechanism. The creep rupture life of the steel increased in presence of triaxial stresses and extent of which was more at lower net applied stresses and higher triaxiality (sharper notch). The reduction in effective stress in presence of notch resulted in higher creep rupture life of the steel under triaxial stresses. The fracture surfaces revealed mixed mode failure consisting of dimple ductile and intergranular creep cavitation for all testing conditions, however, extent of cavitation was higher for relatively higher triaxialities and lower net applied stresses. The creep ductility of the steel was found to decrease drastically under triaxial state of stress. The triaxial rupture life and creep ductility of the steel have been assessed based on different models on incorporating different components of stresses at the skeletal point.

  3. Measuring the triaxial load-deformation response of orthotropic materials subjected to large and small strain regimes

    Treesearch

    Edmond P. Saliklis; Steven M. Cramer; John C. Hermanson

    1998-01-01

    A new method for obtaining triaxial stress versus strain data is presented. The method tests cubic specimens and can provide constitutive data along three mutually perpendicular axes. Issues of removing the effects of boundary conditions in the proposed device are discussed. Two devices were constructed and used to obtain triaxial stress versus strain data on...

  4. Why are the interband transitions among triaxially strongly deformed bands suppressed in even nuclei?

    SciTech Connect

    Sugawara-Tanabe, Kazuko; Tanabe, Kosai

    2011-05-06

    As top-on-top model has made a great success in explaining triaxially strongly deformed (TSD) bands in odd-A nuclei, we extend this model to even-A nuclei, i.e. two particles in different single-particle orbitals outside the triaxial rotor. In the lowest order approximation, the electromagnetic transitions between TSD bands in even-A case are reduced by a factor of 0.04 compared with odd-A case. It is one of the reasons why TSD bands are not yet explicitly observed in even-A nuclei.

  5. 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.

  6. The β-actin gene promoter of rohu carp (Labeo rohita) drives reporter gene expressions in transgenic rohu and various cell lines, including spermatogonial stem cells.

    PubMed

    Barman, Hirak Kumar; Mohanta, Ramya; Patra, Swagat Kumar; Chakrapani, Vemulawada; Panda, Rudra Prasanna; Nayak, Swapnarani; Jena, Sasmita; Jayasankar, Pallipuram; Nandanpawar, Priyanka

    2015-06-01

    We previously characterized the β-actin gene promoter of Indian domesticated rohu carp (Labeo rohita) and made a reporter construct via fusion to green fluorescence protein (GFP) cDNA. In this study, the same construct was used to breed transgenic rohu fish. About 20% of the transgenic offspring showed ubiquitous expression of the reporter GFP gene. In a few of the transgenic fish, we documented massive epithelial and/or muscular expression with visible green color under normal light. The expression of GFP mRNA was higher in the muscle tissue of transgenic fish than in that of non-transgenic fish. A highly efficient nucleofection protocol was optimized to transfect proliferating spermatogonial cells of rohu using this reporter construct. The β-actin promoter also drove expressions in HEK293 (derived from human embryonic kidney cells), K562 (human leukemic cells) and SF21 (insect ovarian cells) lines. These findings imply conserved regulatory mechanisms of β-actin gene expression across eukaryotes. Furthermore, the isolated β-actin promoter with consensus regulatory elements has the potential to be used in generating transgenic carp with genes of interest and in basic biology research.

  7. 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

  8. Ultrastructural characterization of the mesostriatal dopamine innervation in mice, including two mouse lines of conditional VGLUT2 knockout in dopamine neurons.

    PubMed

    Bérubé-Carrière, Noémie; Guay, Ginette; Fortin, Guillaume M; Kullander, Klas; Olson, Lars; Wallén-Mackenzie, Åsa; Trudeau, Louis-Eric; Descarries, Laurent

    2012-02-01

    Despite the increasing use of genetically modified mice to investigate the dopamine (DA) system, little is known about the ultrastructural features of the striatal DA innervation in the mouse. This issue is particularly relevant in view of recent evidence for expression of the vesicular glutamate transporter 2 (VGLUT2) by a subset of mesencephalic DA neurons in mouse as well as rat. We used immuno-electron microscopy to characterize tyrosine hydroxylase (TH)-labeled terminals in the core and shell of nucleus accumbens and the neostriatum of two mouse lines in which the Vglut2 gene was selectively disrupted in DA neurons (cKO), their control littermates, and C57BL/6/J wild-type mice, aged P15 or adult. The three regions were also examined in cKO mice and their controls of both ages after dual TH-VGLUT2 immunolabeling. Irrespective of the region, age and genotype, the TH-immunoreactive varicosities appeared similar in size, vesicular content, percentage with mitochondria, and exceedingly low frequency of synaptic membrane specialization. No dually labeled axon terminals were found at either age in control or in cKO mice. Unless TH and VGLUT2 are segregated in different axon terminals of the same neurons, these results favor the view that the glutamatergic cophenotype of mesencephalic DA neurons is more important during the early development of these neurons than for the establishment of their scarce synaptic connectivity. They also suggest that, in mouse even more than rat, the mesostriatal DA system operates mainly through non-targeted release of DA, diffuse transmission and the maintenance of an ambient DA level.

  9. Laboratory evaluation of mechanical properties of rock using an automated triaxial compression test with a constant mean stress criterion

    SciTech Connect

    Mellegard, K.D.; Pfeifle, T.W.

    1999-07-01

    A computerized, servohydraulic test system has been used in the laboratory to perform axisymmetric, triaxial compression tests on natural rock salt using a load path that maintains constant mean stress. The constant mean stress test protocol illustrates that modern test systems allow a nonstandard load path which can focus on a particular aspect of rock characterization; namely, the onset of dilation. Included are discussions of how the constant mean stress test could be used to investigate material anisotropy and determine elastic moduli. The results from the constant mean stress tests are compared to test results from a traditional test method. The paper also addresses system calibration concerns and the effects of pressure changes on the direct-contact extensometers used to measure strain.

  10. Critical study of the method of calculating virgin rock stresses from measurement results of the CSIR triaxial strain cell

    NASA Astrophysics Data System (ADS)

    Vreede, F. A.

    1981-05-01

    The manual of instructions for the user of the CSIR triaxial rock stress measuring equipment is critically examined. It is shown that the values of the rock stresses can be obtained from the strain gauge records by means of explicit formulae, which makes the manual's computer program obsolete. Furthermore statistical methods are proposed to check for faulty data and inhomogeneity in rock properties and virgin stress. The possibility of non-elastic behavior of the rock during the test is also checked. A new computer program based on the explicit functions and including the check calculations is presented. It is much more efficient than the one in the manual since it does not require computer sub-routines, allowing it to be used directly on any modern computer. The output of the new program is in a format suitable for direct inclusion in the report of an investigation using strain cell results.

  11. 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.

  12. The Response of a Two-Wire Transmission Line to Incident Field and Voltage Excitation, Including the Effects of Higher Order Modes

    DTIC Science & Technology

    1981-08-01

    8217 INCLUDING THE EFFECTS OF HIGHER "ORDER MODES Syracuse University Yehuda Leviatan Arlon T. Adams APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED] C9 2...GRANT NUMSERf() Yecthuda Leviatan Arlon T. Adams F30602-79-C-0011 9. PERNORMING ORGANIZATION NAME ANO ADDRESS 10. PROGRAM ELEMENT, PROJECT, TASK

  13. [Influence of the included angle between anterior aspects of S2 and S1 vertebral bodies on pelvic inlet imaging in mid-line sagittal plane].

    PubMed

    Cai, Hong-ming; Gao, Shu-tu; Cheng, Chuan-de; Wu, Xue-jian; Wang, Wu-chao; Tang, Jin-cheng; Chang, Shou-ya; Duan, Wei-feng; Zhang, Chuan

    2014-08-01

    To analyze the influence of included angle between the anterior aspects of S2 and S vertebral bodies on pelvic inlet imaging in the pelvic midline sagittal plane. Totally 58 axial pelvic CT scans were chosen as study objects including 43 males and 15 females,with an average age of 40.7 years old (ranged,18 to 68 years old). The angles between the anterior aspects of S2 and S1, vertebral bodies and the horizontal plane on midline sagittal CT reconstruction were measured to simulate the optimal S2 and S1 inlet angles. The included angle between the anterior aspects of S2 and S1 vertebral bodies was calculated by subtrocting the S1,inlet angle from the S2 inlet angle defined as a base number. Then, the impact of the calculated included angles on the pelvic inlet imaging was analyzed. Results:The S2 inlet angles averaged (30.5±6.5) degrees; the S inlet angles averaged (25.7±5.9) degrees. The difference between them was significant (t=3.35, P=0.001). Ten patients had zero angle between the anterior aspects of S2 and S1 vertebral bodies; 14 patients had negative angle, averaged-(8.9±8.1) degrees; 34 patients had positive angle,averaged (11.8+6.4) degrees. The difference of included angle between the anterior aspects of S2 and S1 vertebral bodies leads to the difference between S1 inlet view and S2 inlet view in most cases, complicating the pelvic inlet imaging,and affecting the reliability of the application of pelvic inlet view. Utilizing the angles measured on the preoperative midlihe sagittal CT reconstruction to obatin the patient-customized S1 and S2 inlet views could accurately guide the S1 and S2 iliosacral screw insertion.

  14. 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

  15. Dynamical Monte Carlo Simulations of 3-D Galactic Systems in Axisymmetric and Triaxial Potentials

    NASA Astrophysics Data System (ADS)

    Taani, Ali; Vallejo, Juan C.

    2017-06-01

    We describe the dynamical behavior of isolated old ( ⩾ 1Gyr) objects-like Neutron Stars (NSs). These objects are evolved under smooth, time-independent, gravitational potentials, axisymmetric and with a triaxial dark halo. We analysed the geometry of the dynamics and applied the Poincaré section for comparing the influence of different birth velocities. The inspection of the maximal asymptotic Lyapunov (λ) exponent shows that dynamical behaviors of the selected orbits are nearly the same as the regular orbits with 2-DOF, both in axisymmetric and triaxial when (ϕ, qz )= (0,0). Conversely, a few chaotic trajectories are found with a rotated triaxial halo when (ϕ, qz )= (90, 1.5). The tube orbits preserve direction of their circulation around either the long or short axis as appeared in the triaxial potential, even when every initial condition leads to different orientations. The Poincaré section shows that there are 2-D invariant tori and invariant curves (islands) around stable periodic orbits that bound to the surface of 3-D tori. The regularity of several prototypical orbits offer the means to identify the phase-space regions with localized motions and to determine their environment in different models, because they can occupy significant parts of phase-space depending on the potential. This is of particular importance in Galactic Dynamics.

  16. 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.

  17. 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.

  18. Orientation and rotation dynamics of triaxial ellipsoidal tracers in wall turbulence

    NASA Astrophysics Data System (ADS)

    Challabotla, Niranjan Reddy; Zhao, Lihao; Andersson, Helge I.

    2016-12-01

    The rotational dynamics of triaxial ellipsoidal particles in turbulent channel flow have been explored. The non-inertial particles were tracked in a Lagrangian approach in an Eulerian flow field that resulted from a direct numerical simulation. Although the tracer particles translated along with the local fluid, they did not adhere to the local fluid rotation. The triaxial ellipsoids were characterized by two independent shape parameters that both were varied from 0.1 to 10. In spite of the anisotropic velocity field in the channel center, the tumbling of the particles closely resembled earlier results in homogeneous isotropic turbulence. The orientation of the particles varied substantially from the center to the near-wall region where triaxial particles tended to align their major axis in the mean flow direction and their minor axis in the wall-normal direction. These preferential alignments caused the ellipsoid to tumble as a rod about the major axis and like a disk about the minor axis. These observations show the dual nature of triaxial ellipsoids embedded in real turbulence.

  19. 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.

  20. 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.

  1. 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

  2. Wood-based Tri-Axial Sandwich Composite Materials: Design, Fabrication, Testing, Modeling and Application

    Treesearch

    Jinghao Li; John F. Hunt; Shaoqin Gong; Zhiyong Cai

    2014-01-01

    As the demand for sustainable materials increases, there are unique challenges and opportunities to develop light-weight green composites materials for a wide range of applications. Thus wood-based composite materials from renewable forests may provide options for some niche applications while helping to protect our environment. In this paper, the wood-based tri-axial...

  3. Exact diagonalization of the Bohr Hamiltonian for rotational nuclei: Dynamical {gamma} softness and triaxiality

    SciTech Connect

    Caprio, M. A.

    2011-06-15

    Detailed quantitative predictions are obtained for phonon and multiphonon excitations in well-deformed rotor nuclei within the geometric framework, by exact numerical diagonalization of the Bohr Hamiltonian in an SO(5) basis. Dynamical {gamma} deformation is found to significantly influence the predictions through its coupling to the rotational motion. Basic signatures for the onset of rigid triaxial deformation are also obtained.

  4. Simplifying touch data from tri-axial sensors using a new data visualization tool.

    PubMed

    Salud, Lawrence H; Kwan, Calvin; Pugh, Carla M

    2013-01-01

    Quantification and evaluation of palpation is a growing field of research in medicine and engineering. A newly developed tri-axial touch sensor has been designed to capture a multi-dimensional profile of touch-loaded forces. We have developed a data visualization tool as a first step in simplifying interpretation of touch for assessing hands-on clinical performance.

  5. Long-term antimicrobial effect of nisin released from electrospun triaxial fiber membranes.

    PubMed

    Han, Daewoo; Sherman, Shalli; Filocamo, Shaun; Steckl, Andrew J

    2017-02-16

    Electrospun membranes encapsulating nisin in the core of multi-layer coaxial fibers, with a hydrophobic PCL intermediate layer and a hygroscopic cellulose acetate sheath, have been demonstrated to provide long-term antimicrobial activity combined with a hygroscopic outer layer. Antimicrobial performance has been evaluated using modified versions of the antimicrobial textile test AATCC 100 and AATCC 147 against Staphylococcus aureus. The AATCC 147 tests indicate that antimicrobial activity persists up to 7days. The quantitative analysis from the AATCC 100 test indicates that tri-layer coaxial ("triaxial") electrospun fiber membranes provide >99.99% bacteria kill (4logkill) for up to five days. This indicates that the nisin-incorporated triaxial fibers have excellent biocidal activities for up to 5days and then provide biostatic activity for 2 or more days. Compared with other types of electrospun membranes, such as core-sheath coaxial ("coaxial") and single homogenous fibers, triaxial fiber membranes provided more robust and more sustained antimicrobial activity. Single fibers with nisin showed relatively weak activity and only for one day. Coaxial fiber membranes exhibited antimicrobial activity for a long period, but their biocidal activity was much weaker than that of triaxial fiber membranes, and only exhibited >99% bacteria kill (2logkill) after 1day of exposure.

  6. 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.

  7. Triaxial System in Re-Embolization for Recanalization of Pulmonary Arteriovenous Malformations

    PubMed Central

    Shimohira, Masashi; Hashizume, Takuya; Kawai, Tatsuya; Muto, Masahiro; Ohta, Kengo; Suzuki, Kazushi; Shibamoto, Yuta

    2015-01-01

    Summary Background Recanalization occurs occasionally, following coil embolization of pulmonary arteriovenous malformations (PAVM), and can lead to ischemic stroke; therefore re-embolization is important. A 1.9-Fr. no-taper microcatheter that can be inserted into a 2.7-Fr. microcatheter (named the triaxial system) has recently become available, and contributes to super-selective catheterization for small or tortuous vessels. The aim of this study was to evaluate the usefulness of re-embolization for recanalization of PAVM using the triaxial system. Material/Methods Recanalization was diagnosed in 8 patients with 13 PAVMs between June 2011 and November 2012, and re-embolization was attempted with a conventional microcatheter at first in all 13 PAVMs. However, in three of them it failed with the conventional microcatheter, and then the system was exchanged to the triaxial system. Thus, re-embolization using the triaxial system was performed in 3 PAVMs of 3 female patients, with a median age of 63 years (range, 46–73 years). We assessed technical success, complications, and outcome. Results The disappearance of recanalization was confirmed by angiography in all re-embolization procedures (technical success rate was 100%). Re-embolization was then successfully achieved inside the original coils, and no branch artery of normal lung tissue was embolized. There were no complications related with this procedure. The blood flow of recanalization was decreased in all cases in a follow-up of 27–33 months (median, 31). Conclusions Triaxial system appears to be useful for recanalization of PAVM, especially in difficult cases with a conventional system. PMID:25691920

  8. Cytotoxic effects of novel phytosphingosine derivatives, including N,N-dimethylphytosphingosine and N-monomethylphytosphingosine, in human leukemia cell line HL60.

    PubMed

    Park, Sook Ryun; Cho, Hyo Jin; Moon, Kyung Jin; Chun, Kyung-Hee; Kong, Sun-Young; Yoon, Sung-Soo; Lee, Jong Seok; Park, Seonyang

    2010-01-01

    Novel phytosphingosine derivatives have been developed based on the inhibition of sphingosine kinase, which has been implicated in cell growth and inhibition of ceramide-mediated apoptosis. This study evaluated the cytotoxic effects and underlying mechanisms of action of novel phytosphingosine derivatives, including N-monomethylphytosphingosine (MMPH) and N,N-dimethylphytosphingosine (DMPH) and the pegylated forms MMPH-PEG and DMPH-PEG, in human leukemia HL60 cells. In viability and proliferation assays using WST-1, all four drugs induced suppression of cell growth and viability in a concentration-dependent manner. Among them, DMPH had the highest antileukemic activity and induced apoptosis via caspase-8, caspase-3, and caspase-9 activation. The apoptotic effect was also associated with Fas/FasL upregulation, Bid cleavage, Bcl-2 downregulation, Bax upregulation, mitochondrial membrane depolarization, and cytochrome c release. DMPH decreased the phosphorylation of ERK and inhibited daunorubicin-induced ERK activation. Furthermore, DMPH displayed synergistic cytotoxicity with daunorubicin in a sequence-dependent manner. Our findings indicate that DMPH has potential as an effective cytotoxic agent for leukemia.

  9. Analysis of Clinical End Points of Randomised Trials Including Bevacizumab and Chemotherapy versus Chemotherapy as First-line Treatment of Metastatic Colorectal Cancer.

    PubMed

    Colloca, G; Venturino, A; Guarneri, D

    2016-10-01

    Progression-free survival is recognised as an appropriate end point for randomised clinical trials of chemotherapy of patients with metastatic colorectal cancer, although it is not clear if it is reliable after chemotherapy plus bevacizumab. A literature search of randomised trials of systemic treatment including chemotherapy plus bevacizumab versus chemotherapy in patients with metastatic colorectal cancer was undertaken. For each trial the differences in overall survival and in either time-to-event or response-related end points were calculated. A Spearman test was carried out between the difference in each end point and the difference in survival. For the end points with the higher relationships with overall survival a regression analysis was carried out and R(2) (proportion of variability explained) was reported. Progression-free survival is closely related to overall survival (r=0.817; R(2)=0.706) and this relationship does not seem to be changed by the discontinuation of bevacizumab. The response-related end points have a better overall performance than the other time-to-event end points, even when only phase III trials are considered. In phase III trials, the disease control rate seems to be strongly related to overall survival (r=0.975; R(2)=0.889) and the overall response rate reports a good performance (r=0.866; R(2)=0.484). An open-label design and the timing of disease radiological evaluation do not seem to interfere with the correlation of differences of progression-free survival and overall survival. A validation of the disease control rate and the overall response rate as a surrogate end point of survival at a patient level and a standardised definition of the timing for their measurement are strongly recommended in trials of chemotherapy plus bevacizumab. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  10. Tri-axial accelerometer analysis techniques for evaluating functional use of the extremities

    PubMed Central

    Hurd, Wendy J.; Morrow, Melissa M.; Kaufman, Kenton R.

    2013-01-01

    Activity monitors provide an objective mechanism for evaluating patient function. It is unclear what similarities or unique information may be yielded using different analyses. Fifteen patients scheduled to undergo shoulder arthroplasty and fifteen matched control subjects wore tri-axial accelerometer activity monitors bilaterally at the lower (wrist) and upper (biceps) arm for 3 days. Measures of central tendency, variance, sample entropy, and asymmetry were calculated. A novel technique to evaluate time distribution of activity intensity was also performed. Within both groups there was a difference in central tendency and variance when comparing dominant and non-dominant limbs for both the lower (Controls: Mean Activity, P < 0.001; Max Activity, P < 0.001; Patients: Mean Activity, P = 0.044; Max Activity, P = 0.009) and upper (Controls: Mean Activity, P < 0.001; Max Activity, P = 0.046; Patients: Mean Activity, P = 0.002; Max Activity, P = 0.049) arm. Within group differences were also present for lower arm entropy in both groups (Controls, P < 0.001; Patients P = 0.041), and at the upper arm for patients (P = 0.003). There were differences between groups for the asymmetry index for both the lower (P = 0.033) and upper arm (P = 0.005), and maximum activity level of the lower arm (P = 0.05). Between group differences were present for time distribution of activity intensity, as the involved upper arm of patients was inactive for a greater time than controls (P = 0.013). These results highlight unique information provided by multiple analysis methods, and include a novel approach of evaluating the distribution of time spent across variable intensity activities. PMID:23642841

  11. 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.

  12. On-Line Pagination Including Illustrations.

    ERIC Educational Resources Information Center

    Kahle, Roger R.

    The Pagitron electronic composition system offers the potential to manipulate all elements of pagination as easily and as quickly as words are manipulated on computerized text-editing systems. The importance of such an all-encompassing pagination system is that it allows the editorial side of a newspaper or magazine total control over everything…

  13. Modeling Fault Angle in Novel True Triaxial Tests on a Compactive Porous Sandstone

    NASA Astrophysics Data System (ADS)

    Rudnicki, J. W.; Ma, X.; Haimson, B. C.

    2011-12-01

    Ma and Haimson (see accompanying Abstract) have conducted true triaxial tests on a compactive porous sandstone (Coconino) using a novel loading path consisting of keeping the minimum (least compressive) principal stress (σ3) constant but increasing the other two stresses in a fixed ratio. For stress ratios Δσ2/Δσ1 = 1:1; 1:2; 1:3; 1:6; 0 (where Δσi = σi-σ3, and 0 implies σ2 = σ3), the parameter R, describing the deviatoric stress state or Lode angle (and equal to √3N, where N is the parameter used by Rudnicki and Rice (1975)), varies from -1 (axisymmetric extension), to 0 (deviatoric pure shear), to 0.36, 0.71 and +1 (axisymmetric compression). For each value of R, the fault angle decreases roughly linearly with increasing mean stress. A straight line fits plots of the slopes and intercepts of these lines (omitting the points for axisymmetric compression) as a function of R. The resulting bi-linear relationship fits all the data well although for axisymmetric compression the predicted line is slightly offset to the fit to the data. Fault angles are also compared to predictions of a theory that treats fault formation as an alternative to (bifurcation from) homogeneous deformation (Rudnicki and Rice, 1975). Results are based on an inferred dependence of the sum of a friction coefficient μ and dilatancy factor β with mean stress for a single value of R. Using a linear fit to the data for R = 0, gives a plausible variation of μ + β with mean stress: a linear decrease, except at lower values (below about 150 MPa) where the slope decreases. Predictions of the fault angle based on this variation of μ + β agree well with observations for R = 0.36 and R = 0.71. Predictions for axisymmetric compression are slightly offset from the line fitted to the data. For axisymmetric extension the predictions do not agree well with data. For higher mean stress, predicted angles are similar to the data but the variation with mean stress is clearly different. At lower

  14. Triaxial deformation and asynchronous rotation of rocky planets in the habitable zone of low-mass stars

    NASA Astrophysics Data System (ADS)

    Zanazzi, J. J.; Lai, Dong

    2017-08-01

    Rocky planets orbiting M-dwarf stars in the habitable zone tend to be driven to synchronous rotation by tidal dissipation, potentially causing difficulties for maintaining a habitable climate on the planet. However, the planet may be captured into asynchronous spin-orbit resonances, and this capture may be more likely if the planet has a sufficiently large intrinsic triaxial deformation. We derive the analytic expression for the maximum triaxiality of a rocky planet, with and without a liquid envelope, as a function of the planet's radius, density, rigidity and critical strain of fracture. The derived maximum triaxiality is consistent with the observed triaxialities for terrestrial planets in the Solar system, and indicates that rocky planets in the habitable zone of M-dwarfs can in principle be in a state of asynchronous spin-orbit resonances.

  15. A Triaxial Failure Diagram to predict the forming limit of 3D sheet metal parts subjected to multiaxial stresses

    NASA Astrophysics Data System (ADS)

    Rastellini, F.; Socorro, G.; Forgas, A.; Onate, E.

    2016-08-01

    Accurate prediction of failure and forming limits is essential when modelling sheet metal forming processes. Since traditional Forming Limit Curves (FLCs) are not valid for materials subjected to triaxial loading, a new failure criterion is proposed in this paper based on the stress triaxility and the effective plastic strain accumulated during the history of material loading. Formability zones are identified inside the proposed Triaxial Failure Diagram (TFD). FLCs may be mapped into the TFD defining a new Triaxial Failure Curve, or it can be defined by triaxial failure experiments. Several TFD examples are validated and constrasted showing acceptable accuracy in the numerical prediction of forming failure/limit of 3D thick sheet parts.

  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. 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).

  18. Triaxiality of neutron-rich 84,86,88Ge from low-energy nuclear spectra

    NASA Astrophysics Data System (ADS)

    Lettmann, M.; Werner, V.; Pietralla, N.; Doornenbal, P.; Obertelli, A.; Rodríguez, T. R.; Sieja, K.; Authelet, G.; Baba, H.; Calvet, D.; Château, F.; Chen, S.; Corsi, A.; Delbart, A.; Gheller, J.-M.; Giganon, A.; Gillibert, A.; Lapoux, V.; Motobayashi, T.; Niikura, M.; Paul, N.; Roussé, J.-Y.; Sakurai, H.; Santamaria, C.; Steppenbeck, D.; Taniuchi, R.; Uesaka, T.; Ando, T.; Arici, T.; Blazhev, A.; Browne, F.; Bruce, A.; Caroll, R. J.; Chung, L. X.; Cortés, M. L.; Dewald, M.; Ding, B.; Flavigny, F.; Franchoo, S.; Górska, M.; Gottardo, A.; Jungclaus, A.; Lee, J.; Linh, B. D.; Liu, J.; Liu, Z.; Lizarazo, C.; Momiyama, S.; Moschner, K.; Nagamine, S.; Nakatsuka, N.; Nita, C.; Nobs, C. R.; Olivier, L.; Patel, Z.; Podolyák, Zs.; Rudigier, M.; Saito, T.; Shand, C.; Söderström, P.-A.; Stefan, I.; Vaquero, V.; Wimmer, K.; Xu, Z.

    2017-07-01

    γ -ray transitions between low-spin states of the neutron-rich 84,86,88Ge were measured by means of in-flight γ -ray spectroscopy at 270 MeV/u. Excited 61+,41,2 + , and 21,2 + states of Ge,8684 and 41+ and 21,2 + states of 88Ge were observed. Furthermore, a candidate for a 31+ state of 86Ge was identified. This state plays a key role in the discussion of ground-state triaxiality of 86Ge, along with other features of its low-energy level scheme. A new region of triaxially deformed nuclei is proposed in the Ge isotopic chain.

  19. 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.

  20. Motion in the ER3BP with an oblate primary and a triaxial stellar companion

    NASA Astrophysics Data System (ADS)

    Umar, Aishetu; Hussain, Aminu Abubakar

    2016-10-01

    The triangular points of the elliptic restricted three-body problem under an oblate primary and a triaxial and radiating secondary are investigated. Their positions and stability are found to be affected by the eccentricity, semi-major axis, oblateness, triaxiality and radiation pressure. Using Low and High Mass X-ray binaries (LMXB and HMXB), we highlight the effects of the said parameters on the positions of the triangular points of PSR J1903+0327, CEN X-4 and RXJ 04050.01.5658. The triangular points are found to be stable for 0 < μ < μC; where μ is the mass ratio ( μ ≤ 1/2 ). The effects of the parameters on the regions of stability are shown graphically within the stable interval, highlighting their destabilizing tendencies.

  1. Nonadiabatic quasiparticle approach for rotation-particle coupling in triaxial odd-A nuclei

    NASA Astrophysics Data System (ADS)

    Modi, Swati; Patial, M.; Arumugam, P.; Maglione, E.; Ferreira, L. S.

    2017-02-01

    We discuss the formulation of a nonadiabatic approach to study the rotational states in triaxially deformed odd-A nuclei. The rotation-particle coupling is treated microscopically by coupling the triaxial rotor states of the even-even core with the states of the valence particle in order to obtain the matrix elements of the odd-A system. We arrive at a nonadiabatic quasiparticle approach where the rotational states can have contributions from various quasiparticle states near the Fermi level. We bring out the advantages of this approach over the conventional particle rotor model with a fixed or variable moment of inertia. One clear evidence favoring our approach is the rotation alignment phenomenon which is demonstrated in the case of 137Pm. We discuss our results for 136Nd and 137Pm, and justify that this approach is suitable also for studying nuclei away from stability.

  2. Shape Coexistence, Triaxiality, Chiral Bands in Neutron-Rich Nuclei and Hot Fission Mode

    NASA Astrophysics Data System (ADS)

    Hamilton, J. H.; Ramayya, A. V.; Hwang, J. K.; Zhu, S. J.; Luo, Y. X.; Rasmussen, J. O.; Gore, P. M.; Jones, E. F.; Fong, D.; Li, K.; Beyer, C. J.; Chaturvedi, L.; Xu, R. Q.; Yang, L. M.; Jiang, Z.; Zhang, Z.; Xiou, S. D.; Zhang, X. Q.; Ter-Akopian, G. M.; Daniel, A. V.; Oganessian, Yu.; Dimitrov, V.; Frauendorf, S.; Gelberg, A.; Kormicki, J.; Gilat, J.; Lee, I. Y.; Fallon, P.; Cole, J. D.; Drigert, M. W.; Stoyer, M. A.; Ginter, T. N.; Wu, S. C.; Donangelo, R.

    2005-09-01

    The structure of neutron-rich nuclei in the A=100 region have been investigated via prompt γ-γ-γ coincidences in the spontaneous fission of 252Cf at Gammasphere. New levels are observed in 93,95,97Sr, 99,101Y, 101,105Nb, 104,106Mo, 105,107,109Tc, 111,113Rh and 115,117Ag. The level structures show a clear evolution from spherical single particle structures seen in Sr, to symmetric, large prolate deformation in Y, to increasing triaxial shapes with increasing Z in Nb, Mo, Tc, Rh and Ag. Rigid triaxial-plus-rotor calculations were carried out for 107Tc and 111,113Rh. Best fits in 107Tc and 111,113Rb are for prolate β2 ~ 0.3 and γ increasing from -22.5° in 107Tc to near maximum triaxiality, γ = -28° in 111,113Rh. A K= 1/2 intruder band with symmetric deformation is found to coexist with the triaxial asymmetric bands in the Tc and Rh nuclei. In 106Mo, two sets of ΔI=1 bands have all the characteristics of chiral doublets. Tilted axis cranking calculations support the chiral assignment and indicate these form a new type of chiral band with a one and two phonon chiral vibrational nature associated essentially with the neutrons. These new type chiral doublets demonstrate the general nature of chirality in nuclei. Binary yields of Mo-Ba and Ru-Xe were determined with higher accuracy. The hot fission mode is seen only in Mo-Ba where it goes via a type of hyperdeformed shape for 144,145,146Ba with a 4.7% intensity.

  3. Triaxial system in bronchial arterial embolization for haemoptysis using N-butyl-2-cyanoacrylate

    PubMed Central

    Hashimoto, Takeshi; Abematsu, Saori; Hashizume, Takuya; Nakagawa, Motoo; Ozawa, Yoshiyuki; Sakurai, Keita; Shibamoto, Yuta

    2015-01-01

    Objective: The application of bronchial artery embolization (BAE) using N-butyl-2-cyanoacrylate (NBCA) for haemoptysis was recently reported to be useful. A triple co-axial (triaxial) system consisting of a 4-Fr catheter, 2.7-Fr microcatheter and 1.9-Fr no-taper microcatheter has been developed. The aim of the present study was to evaluate the usefulness of the triaxial system in BAE using NBCA. Methods: 12 patients with haemoptysis, 8 males and 4 females with a median age of 64 years (range, 49–88 years), underwent BAE between August 2012 and October 2014. Medical records and images were reviewed, and the technical success rate, clinical success rate, haemoptysis-free rate and complications were evaluated. Technical success was defined as the complete cessation of the target artery as confirmed by digital subtraction angiography, whereas clinical success was defined as the cessation of haemoptysis within 24 h of BAE. Recurrent haemoptysis was defined as a total of >30 ml of bleeding per day. Results: The target artery was embolized successfully in all patients, and the technical success rate was 100% (12/12). The cessation of haemoptysis was achieved in 11 out of 12 patients within 24 h, and thus, the clinical success rate was 92% (11/12). The 6-, 12- and 24-month haemoptysis-free rates were 89%, 89% and 76%, respectively. No patients exhibited any signs of complications such as spinal ischaemia. Conclusion: BAE using the triaxial system and NBCA appears to be a useful and safe procedure for haemoptysis. Advances in knowledge: The triaxial system contributes to safe and effective BAE using NBCA. PMID:26423598

  4. Ductile Fracture Simulation in a Compact Tension Specimen Using a Triaxiality Dependent Cohesive Zone Model

    NASA Astrophysics Data System (ADS)

    Rashid, Faizan Md.; Banerjee, Anuradha

    2014-05-01

    This article reports the results of numerical implementation of a recently proposed versatile cohesive law (TCZM) that incorporates triaxiality of the stress state explicitly in its formulation. TCZM was implemented numerically by devising user-defined elements in ABAQUS v 6.10 for a CT specimen geometry to replicate its fracture behavior as observed in experiments. The measured macroscopic force-deflection curve characteristics show a good agreement with the experimental observations, which illustrates the effectiveness of the TCZM.

  5. Electromagnetic receiver with capacitive electrodes and triaxial induction coil for tunnel exploration

    NASA Astrophysics Data System (ADS)

    Kai, Chen; Sheng, Jin; Wang, Shun

    2017-09-01

    A new type of electromagnetic (EM) receiver has been developed by integrating four capacitive electrodes and a triaxial induction coil with an advanced data logger for tunnel exploration. The new EM receiver can conduct EM observations in tunnels, which is one of the principal goals of surface-tunnel-borehole EM detection for deep ore deposit mapping. The use of capacitive electrodes enables us to record the electrical field (E-field) signals from hard rock surfaces, which are high-resistance terrains. A compact triaxial induction coil integrates three independent induction coils for narrow-tunnel exploration applications. A low-time-drift-error clock source is developed for tunnel applications where GPS signals are unavailable. The three main components of our tunnel EM receiver are: (1) four capacitive electrodes for measuring the E-field signal without digging in hard rock regions; (2) a triaxial induction coil sensor for audio-frequency magnetotelluric and controlled-source audio-frequency magnetotelluric signal measurements; and (3) a data logger that allows us to record five-component MT signals with low noise levels, low time-drift-error for the clock source, and high dynamic range. The proposed tunnel EM receiver was successfully deployed in a mine that exhibited with typical noise characteristics. [Figure not available: see fulltext. Caption: The new EM receiver can conduct EM observations in tunnels, which is one of the principal goals of the surface-tunnel-borehole EM (STBEM) detection for deep ore deposit mapping. The use of a capacitive electrode enables us to record the electrical field (E-field) signals from hard rock surfaces. A compact triaxial induction coil integrated three induction coils, for narrow-tunnel applications.

  6. Measurement of Exercise Intensity with a Tri-Axial Accelerometer during Military Training

    DTIC Science & Technology

    2009-10-01

    PO Box 90.004 3509 AA Utrecht The Netherlands ABSTRACT Exercise load and intensity, as reflected in energy expenditure, are determinants of...sustainable lifestyles. Variance in activity energy expenditure, calculated as total energy expenditure minus resting expenditure, was explained for...acceleration measured with the waist- device. In conclusion, after adjusting for differences in body mass, the newly developed tri-axial accelerometer for

  7. Fatigue behavior of wood-fiber-based tri-axial engineered sandwich composite panels (ESCP)

    Treesearch

    Jinghao Li; John F. Hunt; Shaoqin Gong; Zhiyong Cai

    2015-01-01

    The static and fatigue bending behavior of wood-fiber-based tri-axial engineered sandwich composite panels (ESCP) has been investigated by four-point bending tests. Fatigue panels and weakened panels (wESCP) with an initial interface defect were manufactured for the fatigue tests. Stress σ vs. number of cycles curves (S-N) were recorded under the different stress...

  8. Application of the Satellite Triaxial Accelerometer Experiment to Atmospheric Density and Wind Studies.

    DTIC Science & Technology

    1982-03-04

    EVERETT R. SWIFT U DTIC " 4 MARCH 1982 -J_ OCT 2 9 1 3 Approed for publis rebo.; dlributon unlimited. AERONOMY DIVISION PROJECT 6690 , AIR FORCE...Accelerometers Thermospheric density; . * Aerodynic drag Atmospheric density -- A new satellite triaxial accelerometer system has been developed. This...understanding of dynamic processes in the atmosphere and for the improvement of atmospheric models. i’ :. 4 Unclassified SECURITY CLASSIFICATION OF THIS

  9. Assessment of wear/nonwear time classification algorithms for triaxial accelerometer.

    PubMed

    Choi, Leena; Ward, Suzanne Capen; Schnelle, John F; Buchowski, Maciej S

    2012-10-01

    The objective of this study is to assess the performance of existing wear/nonwear time classification algorithms for accelerometry data collected in the free-living environment using a wrist-worn triaxial accelerometer and a waist-worn uniaxial accelerometer in older adults. Twenty-nine adults age 76 to 96 yr wore wrist accelerometers for approximately 24 h per day and waist accelerometers during waking for approximately 7 d of free living. Wear and nonwear times were classified by existing algorithms (Alg([ActiLife]), Alg([Troiano]), and Alg([Choi])) and compared with wear and nonwear times identified by data plots and diary records. With the use of bias and probability of correct classification, the performance of the algorithms, two time windows (60 and 90 min), and vector magnitude (VM) versus vertical axis (V) counts from a triaxial accelerometer were compared. Automated algorithms (Alg([Choi]) and Alg([Troiano])) classified wear/nonwear time intervals more accurately from VM than V counts. The use of the 90-min time window improved wear/nonwear classification accuracy when compared with the 60-min window. The Alg([Choi]) and Alg([Troiano]) performed better than the manufacturer-provided algorithm (Alg([ActiLife])), and the Alg([Choi]) performed better than the Alg([Troiano]) for wear/nonwear time classification using the data collected by both accelerometers. Triaxial wrist-worn accelerometer can be used for an accurate wear/nonwear time classification in free-living older adults. The use of the 90-min window and the VM counts improves the performance of commonly used algorithms for wear/nonwear classification for both uniaxial and triaxial accelerometers.

  10. Evidence for a triaxial bulge in the spiral galaxy NGC 4845

    SciTech Connect

    Bertola, F.; Zeilinger, W.W.; Rubin, V.C. Carnegie Institution of Washington, Washington, DC )

    1989-10-01

    Spectroscopic observations for the Sa galaxy NGC 4845 in five position angles reveal a regular but nonaxisymmetric velocity field for the gas at r of 1.5 kpc or less. Photometry indicates a possible slight twisting between the disk and bulge isophotes. These phenomena are interpreted as a manifestation of a triaxial bulge, and estimates of the ranges of b/a and c/a are obtained. 20 refs.

  11. 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.

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

    DOE PAGES

    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

  14. 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.

  15. 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.

  16. Analysis of Marshall test behavior with triaxial test determined material properties

    SciTech Connect

    Low, Boonhwee; Tan, Siewann; Fwa, Tienfang )

    1993-01-01

    The Marshall test is one of the most common methods used for mix design and quality control of asphalt concrete mixtures. However, this method is empirical in nature and does not provide fundamental engineering properties. Fundamental engineering properties provide a basis for rational analysis and design of asphalt concrete pavements. The triaxial test method described in this paper allows engineering properties such as internal angle of friction, [phi], cohesion, c, and elastic modulus, E, to be determined. The method of specimen preparation and the triaxial test setup are briefly described. A numerical simulation of the Marshall test is performed using a plane-stress finite element analysis with triaxial test determined properties as input parameters. A constitutive plasticity model based on the Drucker-Prager yield condition is used to describe the elasto-plastic behavior of the specimen. Analysis shows that the model very well describes the deformation progression before failure and can predict experimental Marshall stability value very closely. There is some underprediction of the Marshall flow, probably due to the idealization of an elastic-perfectly-plastic stress-strain relationship for asphalt concrete.

  17. Experimental Study of Slabbing and Rockburst Induced by True-Triaxial Unloading and Local Dynamic Disturbance

    NASA Astrophysics Data System (ADS)

    Du, Kun; Tao, Ming; Li, Xi-bing; Zhou, Jian

    2016-09-01

    Slabbing/spalling and rockburst are unconventional types of failure of hard rocks under conditions of unloading and various dynamic loads in environments with high and complex initial stresses. In this study, the failure behaviors of different rock types (granite, red sandstone, and cement mortar) were investigated using a novel testing system coupled to true-triaxial static loads and local dynamic disturbances. An acoustic emission system and a high-speed camera were used to record the real-time fracturing processes. The true-triaxial unloading test results indicate that slabbing occurred in the granite and sandstone, whereas the cement mortar underwent shear failure. Under local dynamically disturbed loading, none of the specimens displayed obvious fracturing at low-amplitude local dynamic loading; however, the degree of rock failure increased as the local dynamic loading amplitude increased. The cement mortar displayed no failure during testing, showing a considerable load-carrying capacity after testing. The sandstone underwent a relatively stable fracturing process, whereas violent rockbursts occurred in the granite specimen. The fracturing process does not appear to depend on the direction of local dynamic loading, and the acoustic emission count rate during rock fragmentation shows that similar crack evolution occurred under the two test scenarios (true-triaxial unloading and local dynamically disturbed loading).

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

    PubMed

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

    2015-04-03

    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.

  19. The equilibrium points in the perturbed R3BP with triaxial and luminous primaries

    NASA Astrophysics Data System (ADS)

    Singh, Jagadish

    2013-07-01

    This study explores the effects of small perturbations in the Coriolis and centrifugal forces, radiation pressures and triaxiality of the two stars (primaries) on the position and stability of an infinitesimal mass (third body) in the framework of the planar circular restricted three-body problem (R3BP). it is observed that the positions of the usual five (three collinear and two triangular) equilibrium points are affected by the radiation, triaxiality and a small perturbation in the centrifugal force, but are unaffected by that of the Coriolis force. The collinear points are found to remain unstable, while the triangular points are seen to be stable for 0< μ< μ c and unstable for μc ≤μ≤1/2, where μ c is the critical mass ratio influenced by the small perturbations in the Coriolis and centrifugal forces, radiation and triaxiality. It is also noticed that the former one and all the latter three posses stabilizing and destabilizing behavior respectively. Therefore, the overall effect is that the size of the region of stability decreases with increase in the values of the parameters involved.

  20. Energy expenditure estimation during normal ambulation using triaxial accelerometry and barometric pressure.

    PubMed

    Wang, Jingjing; Redmond, Stephen J; Voleno, Matteo; Narayanan, Michael R; Wang, Ning; Cerutti, Sergio; Lovell, Nigel H

    2012-11-01

    Energy expenditure (EE) is an important parameter in the assessment of physical activity. Most reliable techniques for EE estimation are too impractical for deployment in unsupervised free-living environments; those which do prove practical for unsupervised use often poorly estimate EE when the subject is working to change their altitude by walking up or down stairs or inclines. This study evaluates the augmentation of a standard triaxial accelerometry waist-worn wearable sensor with a barometric pressure sensor (as a surrogate measure for altitude) to improve EE estimates, particularly when the subject is ascending or descending stairs. Using a number of features extracted from the accelerometry and barometric pressure signals, a state space model is trained for EE estimation. An activity classification algorithm is also presented, and this activity classification output is also investigated as a model input parameter when estimating EE. This EE estimation model is compared against a similar model which solely utilizes accelerometry-derived features. A protocol (comprising lying, sitting, standing, walking, walking up stairs, walking down stairs and transitioning between activities) was performed by 13 healthy volunteers (8 males and 5 females; age: 23.8 ± 3.7 years; weight: 70.5 ± 14.9 kg), whose instantaneous oxygen uptake was measured by means of an indirect calorimetry system (K4b(2), COSMED, Italy). Activity classification improves from 81.65% to 90.91% when including barometric pressure information; when analyzing walking activities alone the accuracy increases from 70.23% to 98.54%. Using features derived from both accelerometry and barometry signals, combined with features relating to the activity classification in a state space model, resulted in a VO(2) estimation bias of -0.00 095 and precision (1.96SD) of 3.54 ml min(-1) kg(-1). Using only accelerometry features gives a relatively worse performance, with a bias of -0.09 and precision (1.96SD) of 5

  1. SMILE: Orbital analysis and Schwarzschild modeling of triaxial stellar systems

    NASA Astrophysics Data System (ADS)

    Vasiliev, Eugene

    2013-08-01

    SMILE is interactive software for studying a variety of 2D and 3D models, including arbitrary potentials represented by a basis-set expansion, a spherical-harmonic expansion with coefficients being smooth functions of radius (splines), or a set of fixed point masses. Its main features include: orbit integration in various 2d and 3d potentials (including N-body and basis-set representations of an arbitrary potential);methods for analysis of orbital class, fundamental frequencies, regular or chaotic nature of an orbit, computation of Lyapunov exponents;Poincaré sections (in 2d) and frequency maps (in 3d) for analyzing orbital structure of potential;construction of self-consistent Schwarzschild models; andconvenient visualization and integrated GUI environment, and a console scriptable version.SMILE is portable to different platforms including MS Windows, Linux and Mac.

  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. Finite element modeling tests of the seven moment tensor approximation of ground displacement from tri-axial pressurized ellipsoids.

    NASA Astrophysics Data System (ADS)

    Luongo, Annamaria; Amoruso, Antonella; Crescentini, Luca

    2015-04-01

    Volcanic unrests can be studied through the induced surface deformation; one limiting factor however is the small number of available deformation source models. Till 2011, the only available (approximate or exact) expressions for finite expansion sources referred to spheres, prolate spheroids, and horizontal circular cracks embedded in a homogeneous half-space. Cervelli (2013) derived more general approximate expressions for displacement from a finite spheroid of arbitrary orientation and aspect ratio, embedded in a homogeneous half-space. The only approximate expressions for displacements and stresses from the inflation of a finite pressurized tri-axial ellipsoid in a (possibly heterogeneous) half-space were published by Amoruso and Crescentini (2011). Starting from the equivalence (exact for an infinite elastic medium) between the external displacement field due to a pressurized ellipsoidal cavity and the displacement field given by a uniform distribution of seismic moments, Amoruso and Crescentini (2011) accounted for source finiteness by using an approach similar to the multipole expansion of the gravitational potential outside a mass distribution. The dipole term is null because of symmetry; terms to quadrupole order are kept. The resulting expressions can be evaluated by combining the effects of seven moment tensors (SMT model) and are approximately valid also for a heterogeneous half-space. In case of a layered half-space, the appropriate displacement Green functions can be evaluated analitically and the SMT model has already been used to invert ground deformation data of the Campi Flegrei Caldera, Italy. In case of a heterogeneous medium, the appropriate displacement Green functions can be computed, once and for all, using FEM, so that the SMT model still allows fast forward computations and can be included into inversion codes. Amoruso and Crescentini (2011) could test the goodness of their approach only in case of spherical and prolate spheroidal cavities

  4. Tri-Axial Accelerometer-Determined Daily Physical Activity and Sedentary Behavior of Suburban Community-Dwelling Older Japanese Adults.

    PubMed

    Chen, Tao; Narazaki, Kenji; Honda, Takanori; Chen, Sanmei; Haeuchi, Yuki; Nofuji, Yu Y; Matsuo, Eri; Kumagai, Shuzo

    2015-09-01

    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 pointsAccelerometer, that is capable to assess PA more precisely in large scale epidemiological studies, provides opportunity for improving

  5. 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

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

    NASA Astrophysics Data System (ADS)

    Sun, Rong; Shen, Wen Bin

    2016-10-01

    The noise floor of empirical models of the prograde diurnal Earth rotation could reach as low as 1 µas as shown by several recent studies. In another aspect, the differences between these empirical models with the theoretical model predictions given by International Earth Rotation and Reference Systems Service (IERS) Conventions (2010) for certain diurnal frequencies are more than 10 µas (e.g., K1). The triaxiality of the core is ignored in the theoretical model given by IERS Conventions (2010) because it is highly uncertain. To explain the differences between the empirical models and the theoretical model, we consider the possible influence of a triaxial core. We use the differences between the empirical models and the theoretical model predictions given by IERS Conventions (2010) as inputs to invert the triaxiality parameter of the core. In the inversion, we assume the ocean tide response is subjected to the admittance theory. So extra six admittance parameters are introduced to model the differences between the smooth responses inferred from the empirical models and that given by theoretical model predictions from IERS Conventions (2010). The results show that adding core triaxiality into the theoretical model could narrow the differences between the empirical models and the theoretical model at the prograde diurnal band. As for the dynamical equatorial flattening of the core, the estimates inverted based on the different empirical models are consistent within standard deviation. The results also suggest that the principal axes of the triaxial core do not coincide with the principal axes of the whole Earth.

  7. A grasping forceps with a triaxial MEMS tactile sensor for quantification of stresses on organs.

    PubMed

    Kuwana, K; Nakai, A; Masamune, K; Dohi, T

    2013-01-01

    This paper reports on a grasping forceps with a triaxial Micro Electro Mechanical Systems (MEMS) tactile sensor on a tip. The laparoscopic surgery is minimally invasive because the incisions are smaller than the open surgery. This results in fast recovery. However, it is a problem in the laparoscopic surgery to damage an organ by localized stress generated by grasping with a thin forceps. To avoid excessive stress applying to the organ, real time evaluation of the stress is important. However, there is no acceptable tool to measure the stress. We propose a grasping forceps with a triaxial MEMS tactile sensor on a tip for a measurement tool. We attached a triaxial MEMS tactile sensor which we have developed on a tip of a grasping forceps. The MEMS sensor can measure not only the pressure but also two directional shear stresses applied to the sensor surface. The sensor size is 7 mm × 7 mm × 2 mm. It is enough small to attach the sensor to the tip of a forceps 12 mm in diameter. In this paper, the characteristics of the forceps with the MEMS sensor during grasping, pushing and pulling actions were evaluated. In these experiments, output of each sensor for pressure and shear stress was proportional to the applied stresses, respectively. Moreover, as an in vivo experiment, we measured the shear stress applied to a pig liver block when it is lifted after being grasped with the forceps. We obtained that the shear stress applied to the liver block increased with the increase of the weight of the liver block.

  8. Uniaxial and triaxial compression tests of silicon carbide ceramics under quasi-static loading condition.

    SciTech Connect

    Brannon, Rebecca Moss; Lee, Moo Yul; Bronowski, David R.

    2005-02-01

    To establish mechanical properties and failure criteria of silicon carbide (SiC-N) ceramics, a series of quasi-static compression tests has been completed using a high-pressure vessel and a unique sample alignment jig. This report summarizes the test methods, set-up, relevant observations, and results from the constitutive experimental efforts. Results from the uniaxial and triaxial compression tests established the failure threshold for the SiC-N ceramics in terms of stress invariants (I{sub 1} and J{sub 2}) over the range 1246 < I{sub 1} < 2405. In this range, results are fitted to the following limit function (Fossum and Brannon, 2004) {radical}J{sub 2}(MPa) = a{sub 1} - a{sub 3}e -a{sub 2}(I{sub 1}/3) + a{sub 4} I{sub 1}/3, where a{sub 1} = 10181 MPa, a{sub 2} = 4.2 x 10{sup -4}, a{sub 3} = 11372 MPa, and a{sub 4} = 1.046. Combining these quasistatic triaxial compression strength measurements with existing data at higher pressures naturally results in different values for the least-squares fit to this function, appropriate over a broader pressure range. These triaxial compression tests are significant because they constitute the first successful measurements of SiC-N compressive strength under quasistatic conditions. Having an unconfined compressive strength of {approx}3800 MPa, SiC-N has been heretofore tested only under dynamic conditions to achieve a sufficiently large load to induce failure. Obtaining reliable quasi-static strength measurements has required design of a special alignment jig and load-spreader assembly, as well as redundant gages to ensure alignment. When considered in combination with existing dynamic strength measurements, these data significantly advance the characterization of pressure-dependence of strength, which is important for penetration simulations where failed regions are often at lower pressures than intact regions.

  9. 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).

  10. Strength Behavior, Creep Failure and Permeability Change of a Tight Marble Under Triaxial Compression

    NASA Astrophysics Data System (ADS)

    Liu, Zaobao; Shao, Jianfu

    2017-03-01

    The coupled hydro-mechanical behaviors of a tight marble are investigated by a series of laboratory tests with continuous gas injection during the hydrostatic compression, triaxial compression and compressive creep tests. Hydrostatic compression tests are firstly carried out in three steps to identify the viscous effect of hydrostatic stress on deformation and permeability of the marble. Coupled triaxial tests are then conducted at a constant axial strain rate under five different confining pressures ( P c) with continuous gas injection. Coupled creep behaviors of the marble are also characterized by a constant deviatoric stress test under P c = 30 MPa with gas flowing at a constant injection pressure. The high-stress unloading failure behavior of the marble is finally investigated by an unloading test with a previous multi-step creep phase to realize a high-stress state as well as to investigate the time-dependent deformation of marble under different deviatoric stresses. Experimental results reveal that gas permeability of the marble shows an evident rate-dependent effect in hydrostatic compression. Mechanical behaviors of the tight marble are closely depended on the applied P c in triaxial tests, and its permeability exhibits a decrease phase at initial deviatoric loading and turns to increase at a critical stress corresponding to the initial yield stress. Marble can withstand more important plastic deformation under high P c than under lower ones. Gas flow seems to be more sensitive than the strains to characterize the creep behaviors of the marble. No time-dependent strains are observed when deviatoric creep stress is lower than 50% of its peak strength under P c = 30 MPa.

  11. Improvements of J-integral criterion for ductile fracture characterized by a triaxiality parameter

    NASA Astrophysics Data System (ADS)

    Wang, Tie-Jun

    1994-05-01

    It is now generally agreed that the applicability of the one-parameter J-based fracture approach is limited to so-called high-constraint crack geometries and the research of alternate methods is needed. This paper proposes to employ damage mechanics models for ductile fracture to correlate the variability of macroscopic fracture toughness values (J(sub 1c)) with crack tip constraint characterized by crack tip stress triaxiality (S(sub m)/S(sub e)). Firstly, a continuum damage mechanics model and an improved micromechanics model for ductile fracture proposed by the author are introduced briefly. Then the experimental results on the stress-state dependence of the critical J-value, denoted J(sub 1c), at crack initiation are reviewed, and the relationship between J(sub 1c) and the stress triaxiality factor, S(sub m)/S(sub e), in the crack tip region are derived on the basis of the two damage mechanics models. Finally, modified fracture parameters J(sub dc) and J(sub mc) and the associated two-parameter (J and S(sub m)/S(sub e)) criteria for ductile fracture are proposed, where the J-integral sets the deformation at the crack tip and the stress triaxiality S(sub m)/S(sub e) sets the crack tip constraint, which are the improvements on the one-parameter J-integral criterion. Experiments verified that the newly improved parameters J(sub dc) and J(sub mc) are material constants independent of stress state, i.e. specimen geometry and loading condition-independent constants.

  12. 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.

  13. Locomotive and non-locomotive activity as determined by triaxial accelerometry and physical fitness in Japanese preschool children.

    PubMed

    Tanaka, Chiaki; Hikihara, Yuki; Ohkawara, Kazunori; Tanaka, Shigeho

    2012-08-01

    This study examined the potential relationship between participation in physical activity (PA) assessed by triaxial accelerometry and physical fitness testing, including health-related and skill-related parameters of fitness, in 136 Japanese preschoolers (65 girls and 71 boys, 5.5 ± 0.6 years). In partial correlation analyses, grip strength and 20m shuttle run test were positively correlated with time spent in physical activity ratio (PAR) ≥ 4. Better scores on standing long jump distance and jump over and crawl under tests were associated with lower sedentary time and greater moderate-to-vigorous PA time and PAR ≥ 4 time, and increased physical activity level. Moreover, 25m run speed was positively correlated with time spent in PAR ≥ 4 and locomotive activity. These findings suggest that development of both health-related (muscle strength and aerobic fitness) and skill-related fitness (power, agility and speed) may make engagement in PA easier for preschool children, although further research on the cause-effect relationship is needed.

  14. Meso-Scale Progressive Damage Behavior Characterization of Triaxial Braided Composites under Quasi-Static Tensile Load

    NASA Astrophysics Data System (ADS)

    Ren, Yiru; Zhang, Songjun; Jiang, Hongyong; Xiang, Jinwu

    2017-08-01

    Based on continuum damage mechanics (CDM), a sophisticated 3D meso-scale finite element (FE) model is proposed to characterize the progressive damage behavior of 2D Triaxial Braided Composites (2DTBC) with 60° braiding angle under quasi-static tensile load. The modified Von Mises strength criterion and 3D Hashin failure criterion are used to predict the damage initiation of the pure matrix and fiber tows. A combining interface damage and friction constitutive model is applied to predict the interface damage behavior. Murakami-Ohno stiffness degradation scheme is employed to predict the damage evolution process of each constituent. Coupling with the ordinary and translational symmetry boundary conditions, the tensile elastic response including tensile strength and failure strain of 2DTBC are in good agreement with the available experiment data. The numerical results show that the main failure modes of the composites under axial tensile load are pure matrix cracking, fiber and matrix tension failure in bias fiber tows, matrix tension failure in axial fiber tows and interface debonding; the main failure modes of the composites subjected to transverse tensile load are free-edge effect, matrix tension failure in bias fiber tows and interface debonding.

  15. 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.

  16. Submicrosecond isomer in 45117Rh72 and the role of triaxiality in its electromagnetic decay rate

    NASA Astrophysics Data System (ADS)

    Lalkovski, S.; Bruce, A. M.; Denis Bacelar, A. M.; Górska, M.; Pietri, S.; Podolyák, Zs.; Bednarczyk, P.; Caceres, L.; Casarejos, E.; Cullen, I. J.; Doornenbal, P.; Farrelly, G. F.; Garnsworthy, A. B.; Geissel, H.; Gelletly, W.; Gerl, J.; Grębosz, J.; Hinke, C.; Ilie, G.; Ivanova, D.; Jaworski, G.; Kisyov, S.; Kojouharov, I.; Kurz, N.; Minkov, N.; Myalski, S.; Palacz, M.; Petkov, P.; Prokopowicz, W.; Regan, P. H.; Schaffner, H.; Steer, S.; Tashenov, S.; Walker, P. M.; Wollersheim, H. J.

    2013-08-01

    The neutron-rich nucleus 117Rh was synthesized in the fission of a relativistic 238U beam produced at the GSI laboratory in Darmstadt, Germany. An isomeric state with t1/2=138(17) ns decaying by a single γ ray was observed, providing the first information on the excited states in this nucleus. The experimental data are discussed in terms of systematics and interpreted by using the Woods-Saxon deformed shell model and triaxial-rotor-plus-particle calculations. The origin of the isomer is explained as being due to a hindered E2 transition to the ground state.

  17. 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.

  18. Reorientation of the rotation axis of triaxial viscoelastic icy moons: Europa and Titan

    NASA Astrophysics Data System (ADS)

    Jara Orue, H. M.; Vermeersen, L. L. A.

    2011-10-01

    We provide an analysis of the rotational response of triaxial viscoelastic icy moons, focusing on the free rotational behavior of Europa and Titan. In a similar way as for terrestrial planets, the rotational behavior of icy moons is dominated by a secular shift of the pole and the periodic Chandler wobble. However, unlike terrestrial planets, the Chandler wobble of icy moons is associated with the viscoelastic response of the layers located below the ocean. The fast relaxation of low-viscous ice layers induces additional wobble frequencies. However, these wobbles are generally weak compared to the strength of the main Chandler wobble.

  19. Interband B (E2) ratios in the rigid triaxial model, a review

    NASA Astrophysics Data System (ADS)

    Gupta, J. B.; Sharma, S.

    1989-01-01

    Uptodate accurate extensive data on γ-g B(E2) ratios for even-even rare-earth nuclei is compared with the predictions of the rigid triaxial model of collective rotation to search for a correlation between the nuclear structure variation with Z, N and the γ0 parameter of the model. The internal consistency in the predictions of the model is investigated and the spectral features vis-a-vis the γ-soft and the γ-rigid potential are discussed.

  20. Triaxial superdeformed and normal-deformed high-spin band structures in {sup 170}Hf

    SciTech Connect

    Neusser-Neffgen, A.; Huebel, H.; Bringel, P.; Domscheit, J.; Mergel, E.; Nenoff, N.; Singh, A.K.; Hagemann, G.B.; Jensen, D.R.; Bhattacharya, S.; Curien, D.; Dorvaux, O.; Hannachi, F.; Lopez-Martens, A.

    2006-03-15

    The high-spin structure of {sup 170}Hf was investigated using the EUROBALL spectrometer. The previously known level scheme was extended in the low-spin region as well as to higher spins, and several new bands were discovered. In particular, two bands were identified which show the characteristics of triaxial superdeformation. One of these bands is strongly populated, and its excitation energy and spins are established. Configuration assignments are made to the normal-deformed bands based on comparisons of their properties with cranked shell model calculations. The results for the very high spin states provide important input for such calculations.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. A Novel True Triaxial Apparatus to Study the Geomechanical and Fluid Flow Aspects of Energy Exploitations in Geological Formations

    NASA Astrophysics Data System (ADS)

    Li, Minghui; Yin, Guangzhi; Xu, Jiang; Li, Wenpu; Song, Zhenlong; Jiang, Changbao

    2016-12-01

    Fluid-solid coupling investigations of the geological storage of CO2, efficient unconventional oil and natural gas exploitations are mostly conducted under conventional triaxial stress conditions ( σ 2 = σ 3), ignoring the effects of σ 2 on the geomechanical properties and permeability of rocks (shale, coal and sandstone). A novel multi-functional true triaxial geophysical (TTG) apparatus was designed, fabricated, calibrated and tested to simulate true triaxial stress ( σ 1 > σ 2 > σ 3) conditions and to reveal geomechanical properties and permeability evolutions of rocks. The apparatus was developed with the capacity to carry out geomechanical and fluid flow experiments at high three-dimensional loading forces and injection pressures under true triaxial stress conditions. The control and measurement of the fluid flow with effective sealing of rock specimen corners were achieved using a specially designed internally sealed fluid flow system. To validate that the apparatus works properly and to recognize the effects of each principal stress on rock deformation and permeability, stress-strain and permeability experiments and a hydraulic fracturing simulation experiment on shale specimens were conducted under true triaxial stress conditions using the TTG apparatus. Results show that the apparatus has advantages in recognizing the effects of σ 2 on the geomechanical properties and permeability of rocks. Results also demonstrate the effectiveness and reliability of the novel TTG apparatus. The apparatus provides a new method of studying the geomechanical properties and permeability evolutions of rocks under true triaxial stress conditions, promoting further investigations of the geological storage of CO2, efficient unconventional oil and gas exploitations.

  7. In situ triaxial magnetic field compensation for the spin-exchange-relaxation-free atomic magnetometer.

    PubMed

    Fang, Jiancheng; Qin, Jie

    2012-10-01

    The spin-exchange-relaxation-free (SERF) atomic magnetometer is an ultra-high sensitivity magnetometer, but it must be operated in a magnetic field with strength less than about 10 nT. Magnetic field compensation is an effective way to shield the magnetic field, and this paper demonstrates an in situ triaxial magnetic field compensation system for operating the SERF atomic magnetometer. The proposed hardware is based on optical pumping, which uses some part of the SERF atomic magnetometer itself, and the compensation method is implemented by analyzing the dynamics of the atomic spin. The experimental setup for this compensation system is described, and with this configuration, a residual magnetic field of strength less than 2 nT (±0.38 nT in the x axis, ±0.43 nT in the y axis, and ±1.62 nT in the z axis) has been achieved after compensation. The SERF atomic magnetometer was then used to verify that the residual triaxial magnetic fields were coincident with what were achieved by the compensation system.

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

    SciTech Connect

    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 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. 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.

  9. Orientational dynamics of a triaxial ellipsoid in simple shear flow: Influence of inertia

    NASA Astrophysics Data System (ADS)

    Rosén, Tomas; Kotsubo, Yusuke; Aidun, Cyrus K.; Do-Quang, Minh; Lundell, Fredrik

    2017-07-01

    The motion of a single ellipsoidal particle in simple shear flow can provide valuable insights toward understanding suspension flows with nonspherical particles. Previously, extensive studies have been performed on the ellipsoidal particle with rotational symmetry, a so-called spheroid. The nearly prolate ellipsoid (one major and two minor axes of almost equal size) is known to perform quasiperiodic or even chaotic orbits in the absence of inertia. With small particle inertia, the particle is also known to drift toward this irregular motion. However, it is not previously understood what effects from fluid inertia could be, which is of highest importance for particles close to neutral buoyancy. Here, we find that fluid inertia is acting strongly to suppress the chaotic motion and only very weak fluid inertia is sufficient to stabilize a rotation around the middle axis. The mechanism responsible for this transition is believed to be centrifugal forces acting on fluid, which is dragged along with the rotational motion of the particle. With moderate fluid inertia, it is found that nearly prolate triaxial particles behave similarly to the perfectly spheroidal particles. Finally, we also are able to provide predictions about the stable rotational states for the general triaxial ellipsoid in simple shear with weak inertia.

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

    DOE PAGES

    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

  11. Mechanical behavior of municipal solid waste incinerator bottom ash: Results from triaxial tests.

    PubMed

    Le, Ngoc Hung; Abriak, Nor Edine; Binetruy, Christophe; Benzerzour, Mahfoud; Nguyen, Sy-Tuan

    2017-07-01

    Bottom ash resulting from the incineration of various domestic wastes can be viewed as a typical granular material. It is mainly used in civil engineering as a substitute for traditional natural aggregates. The purpose of this paper is to characterize their mechanical behavior and evaluate their mechanical properties for engineering applications. First, results of triaxial tests confirm that bottom ash behaves like dense sand. Second, the deformation and strength characteristics of bottom ash, such as the secant modulus, Poisson ratio, characteristic angle, dilation angle, effective cohesion and effective friction angle, are determined. It is found that these mechanical parameters are in close agreement with those of road aggregates and are influenced by the effective confining pressure. Third, the evolution of the deformation modulus according to the axial strain and the variation of the deviator stress according to the mean effective pressure are analyzed. Finally, a set of points of the yielding state is determined from triaxial tests to represent the shape of the yielding surface of bottom ash. Copyright © 2017. Published by Elsevier Ltd.

  12. Self-consistent models for triaxial galaxies with flat rotation curves - The disk case

    NASA Technical Reports Server (NTRS)

    Kuijken, Konrad

    1993-01-01

    We examine the possibility of constructing scale-free triaxial logarithmic potentials self-consistently, using Schwarzschild's linear programing method. In particular, we explore the limit of nonaxisymmetric disks. In this case it is possible to reduce the problem to the self-consistent reconstruction of the disk surface density on the unit circle, a considerably simpler problem than the usual 2D or 3D one. Models with surface densities of the form Sigma = (x exp n + (y/q) exp n) exp - 1/n with n = 2 or 4 are investigated. We show that the complicated shapes of the 'boxlet' orbit families (which replace the box orbit family found in potentials with smooth cores) limit the possibility of building self-consistent models, though elliptical disks of axis ratio above 0.7 and a restricted range of boxier models can be constructed. This result relies on using sufficiently fine bins, smaller than the 10 deg bins commonly used in 2D or 3D investigations. It also indicates the need for caution in interpreting N-body models of triaxial halos in which the core of the potential is numerically smoothed.

  13. 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.

  14. 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.

  15. 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.

  16. Triaxiality and Exotic Rotations at High Spins in 134Ce

    SciTech Connect

    Petrache, C. M.; 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.

    2016-06-06

    High-spin states in Ce-134 have been investigated using the Cd-116(Ne-22,4n) reaction and the Gammasphere array. The level scheme has been extended to an excitation energy of similar to 30 MeV and spin similar to 54 (h) over bar. 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.

  17. The SLUGGS survey: outer triaxiality of the fast rotator elliptical NGC 4473

    NASA Astrophysics Data System (ADS)

    Foster, Caroline; Arnold, Jacob A.; Forbes, Duncan A.; Pastorello, Nicola; Romanowsky, Aaron J.; Spitler, Lee R.; Strader, Jay; Brodie, Jean P.

    2013-11-01

    Systematic surveys of nearby early-type galaxies using integral field unit (IFU) spectrograph data have revealed that galaxies can hide interesting structures only visible through kinematic studies. As part of their pioneering work, the ATLAS3D team have shown that most morphologically elliptical galaxies are centrally kinematically disc like. Hence, while global morphology suggests that ellipticals are ellipsoidal/triaxial in shape, their central kinematics may be consistent with (inclined) oblate systems. Here, we study the fast rotator elliptical galaxy: NGC 4473. Using slitlets, we obtain galaxy light kinematics out to unprecedentedly large galactocentric radii (2.5 effective radii). While we confirm the IFU results in the central regions, we find that at large galactocentric radii NGC 4473 exhibits a kinematic transition. In the outskirts, we observe clear minor and major axis rotation, a tell-tale sign of triaxiality, which agrees well with the galaxy's Hubble type. This outer `kinematically distinct halo' may be expected from simulations of galaxy formation, and in this system contains around one-third of the stellar light. While this galaxy may be a special case, it suggests that further investigation of the outskirts of galaxies is needed to confirm the new paradigm of galaxy classification.

  18. Triaxiality and Exotic Rotations at High Spins in 134Ce

    SciTech Connect

    Petrache, C. M.; 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.

    2016-06-06

    High-spin states in Ce-134 have been investigated using the Cd-116(Ne-22,4n) reaction and the Gammasphere array. The level scheme has been extended to an excitation energy of similar to 30 MeV and spin similar to 54 (h) over bar. 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.

  19. 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.

  20. 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.

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

    PubMed

    Martin, James E

    2016-07-07

    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.

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

    PubMed

    Xia, Dunzhu; Kong, Lun; Gao, Haiyu

    2015-11-17

    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.

  3. 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

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

    SciTech Connect

    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 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. 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.

  5. Self-consistent models for triaxial galaxies with flat rotation curves - The disk case

    NASA Technical Reports Server (NTRS)

    Kuijken, Konrad

    1993-01-01

    We examine the possibility of constructing scale-free triaxial logarithmic potentials self-consistently, using Schwarzschild's linear programing method. In particular, we explore the limit of nonaxisymmetric disks. In this case it is possible to reduce the problem to the self-consistent reconstruction of the disk surface density on the unit circle, a considerably simpler problem than the usual 2D or 3D one. Models with surface densities of the form Sigma = (x exp n + (y/q) exp n) exp - 1/n with n = 2 or 4 are investigated. We show that the complicated shapes of the 'boxlet' orbit families (which replace the box orbit family found in potentials with smooth cores) limit the possibility of building self-consistent models, though elliptical disks of axis ratio above 0.7 and a restricted range of boxier models can be constructed. This result relies on using sufficiently fine bins, smaller than the 10 deg bins commonly used in 2D or 3D investigations. It also indicates the need for caution in interpreting N-body models of triaxial halos in which the core of the potential is numerically smoothed.

  6. A novel portable energy dispersive X-ray fluorescence spectrometer with triaxial geometry

    NASA Astrophysics Data System (ADS)

    Pessanha, S.; Alves, M.; Sampaio, J. M.; Santos, J. P.; Carvalho, M. L.; Guerra, M.

    2017-01-01

    The X-ray fluorescence technique is a powerful analytical tool with a broad range of applications such as quality control, environmental contamination by heavy metals, cultural heritage, among others. For the first time, a portable energy dispersive X-ray fluorescence spectrometer was assembled, with orthogonal triaxial geometry between the X-ray tube, the secondary target, the sample and the detector. This geometry reduces the background of the measured spectra by reducing significantly the Bremsstrahlung produced in the tube through polarization in the secondary target and in the sample. Consequently, a practically monochromatic excitation energy is obtained. In this way, a better peak-background ratio is obtained compared to similar devices, improving the detection limits and leading to superior sensitivity. The performance of this setup is compared with the one of a benchtop setup with triaxial geometry and a portable setup with planar geometry. Two case studies are presented concerning the analysis of a 18th century paper document, and the bone remains of an individual buried in the early 19th century.

  7. 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.

  8. 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.

  9. 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.

  10. Nanosized sustained-release drug depots fabricated using modified tri-axial electrospinning.

    PubMed

    Yang, Guang-Zhi; Li, Jiao-Jiao; Yu, Deng-Guang; He, Mei-Feng; Yang, Jun-He; Williams, Gareth R

    2017-01-27

    Nanoscale drug depots, comprising a drug reservoir surrounded by a carrier membrane, are much sought after in contemporary pharmaceutical research. Using cellulose acetate (CA) as a filament-forming polymeric matrix and ferulic acid (FA) as a model drug, nanoscale drug depots in the form of core-shell fibers were designed and fabricated using a modified tri-axial electrospinning process. This employed a solvent mixture as the outer working fluid, as a result of which a robust and continuous preparation process could be achieved. The fiber-based depots had a linear morphology, smooth surfaces, and an average diameter of 0.62±0.07μm. Electron microscopy data showed them to have clear core-shell structures, with the FA encapsulated inside a CA shell. X-ray diffraction and IR spectroscopy results verified that FA was present in the crystalline physical form. In vitro dissolution tests revealed that the fibers were able to provide close to zero-order release over 36h, with no initial burst release and minimal tailing-off. The release properties of the depot systems were much improved over monolithic CA/FA fibers, which exhibited a significant burst release and also considerable tailing-off at the end of the release experiment. Here we thus demonstrate the concept of using modified tri-axial electrospinning to design and develop new types of heterogeneous nanoscale biomaterials.

  11. Spatial Structure of Regular and Chaotic Orbits in A Self-Consistent Triaxial Stellar System

    NASA Astrophysics Data System (ADS)

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

    2005-01-01

    We created a triaxial stellar system through the cold dissipationless collapse of 100,000 particles whose evolution was followed with a multipolar code. Once an equilibrium system had been obtained, the multipolar expansion was freezed and smoothed in order to get a stationary smooth potential. The resulting model was self-consistent and the orbits and Lyapunov exponents could then be computed for a randomly selected sample of 3472 of the bodies that make up the system. More than half of the orbits (52.7 % ) turned out to be chaotic. Regular orbits were then classified using the frequency analysis automatic code of Carpintero and Aguilar (1998, MNRAS 298(1), 1 21). We present plots of the distributions of the different kinds of orbits projected on the symmetry planes of the system. We distinguish chaotic orbits with only one non-zero Lyapunov exponent from those with two non-zero exponents and show that their spatial distributions differ, that of the former being more similar to the one of the regular orbits. Most of the regular orbits are boxes and boxlets, but the minor axis tubes play an important role filling in the wasp waists of the boxes and helping to give a lentil shape to the system. We see no problem in building stable triaxial models with substantial amounts of chaotic orbits; the difficulties found by other authors may be due not to a physical cause but to a limitation of Schwarzschild’s method.

  12. 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.

  13. Reliability of Triaxial Accelerometry for Measuring Load in Men's Collegiate Ice-Hockey.

    PubMed

    Van Iterson, Erik H; Fitzgerald, John S; Dietz, Calvin C; Snyder, Eric M; Peterson, Ben J

    2016-08-18

    Wearable microsensor technology incorporating triaxial accelerometry is used to quantify an index of mechanical stress associated with sport-specific movements termed PlayerLoad™. The test-retest reliability of PlayerLoad™ in the environmental-setting of ice-hockey is unknown. The primary aim of this study was to quantify the test-retest reliability of PlayerLoad™ in ice-hockey players during performance of tasks simulating game-conditions. Division I collegiate male ice-hockey players (N=8) wore Catapult Optimeye S5 monitors during repeat performance of 9 ice-hockey tasks simulating game-conditions. Ordered ice-hockey tasks during repeated bouts included: acceleration (forward/backward), 60% top-speed, top-speed (forward/backward), repeated shift circuit, ice-coasting, slap-shot, and bench-sitting. Coefficient of variation (CV), intraclass correlation coefficient (ICC), and minimum differences (MD) were used to assess PlayerLoad™ reliability. Test-retest CVs and ICCs of PlayerLoad™ were: Forward (8.6, 0.54) or backward (13.8, 0.78) acceleration, 60% top-speed (2.2, 0.96), forward (7.5, 0.79) or backwards (2.8, 0.96) top-speed, repeated-shift test (26.6, 0.95), slap-shot (3.9, 0.68), coasting (3.7, 0.98), and bench-sitting (4.1, 0.98), respectively. Raw differences between bouts were not significant for ice-hockey tasks (P>0.05). For each task, between bout raw differences were lower versus MD: Forward (0.06 vs. 0.35) or backward (0.07 vs. 0.36) acceleration, 60% top-speed (0.00 vs. 0.06), forward (0.03 vs. 0.20) or backwards (0.02 vs. 0.09) top-speed, repeated-shift test (0.18 vs. 0.64), slap-shot (0.02 vs. 0.10), coasting (0.00 vs. 0.10), and bench-sitting (0.01 vs. 0.11), respectively. These data suggest PlayerLoad™ demonstrates moderate-to-large test-retest reliability in the environmental-setting of male Division I collegiate ice-hockey. Without previously testing reliability, these data are important as PlayerLoad™ is routinely quantified in

  14. The damping of forced librations of triaxial satellites with eccentric orbits: Consequences on the dynamics of Mimas

    NASA Astrophysics Data System (ADS)

    Caudal, Gérard

    2017-04-01

    Saturn's moon Mimas is a triaxial body orbiting close to the planet on an eccentric orbit, and as a consequence it is librating significantly. Libration is usually believed to enhance dissipation within a planetary satellite. In this paper Mimas' poorly understood strong inward migration obtained by Lainey et al. (2012a) is interpreted as an effect of dissipation within the librating moon. Tajeddine et al. (2014) performed observations of the phase and amplitude of libration and proposed several interior models, from which they retained only two models compatible with observations: a solid body with nonhydrostatic core, or a 3-layer body including an inner dense core, surrounded by a water ocean and an icy solid shell. In this paper I combined three major observations: libration amplitude and libration phase observed by Tajeddine et al. (2014), and inward migration da/dt obtained by Lainey et al. (2012a). A further study by Lainey et al. (2015) however tends to indicate that the Mimas' strong inward motion might be questioned, and therefore this paper also explores situations with smaller da/dt. Within the assumption that inward migration is mainly due to librational dissipation, the solid model with nonhydrostatic core is found to be inconsistent with the observations. In contrast, a 3-layer model including core, ocean and shell is compatible. The observations permit to determine the icy shell depth h, core equatorial flattening βi and core pendulum quality factor QPei, provided that an assumption is made concerning the core density. Due to the uncertainty of da/dt inferred from observations, the value of QPei is however rather uncertain. Dissipation within the oceanic boundary layers is found to contribute significantly to the total dissipated power.

  15. 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

  16. 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…

  17. Flow and fracture behavior of aluminum alloy 6082-T6 at different tensile strain rates and triaxialities.

    PubMed

    Chen, Xuanzhen; Peng, Yong; Peng, Shan; Yao, Song; Chen, Chao; Xu, Ping

    2017-01-01

    This study aims to investigate the flow and fracture behavior of aluminum alloy 6082-T6 (AA6082-T6) at different strain rates and triaxialities. Two groups of Charpy impact tests were carried out to further investigate its dynamic impact fracture property. A series of tensile tests and numerical simulations based on finite element analysis (FEA) were performed. Experimental data on smooth specimens under various strain rates ranging from 0.0001~3400 s-1 shows that AA6082-T6 is rather insensitive to strain rates in general. However, clear rate sensitivity was observed in the range of 0.001~1 s-1 while such a characteristic is counteracted by the adiabatic heating of specimens under high strain rates. A Johnson-Cook constitutive model was proposed based on tensile tests at different strain rates. In this study, the average stress triaxiality and equivalent plastic strain at facture obtained from numerical simulations were used for the calibration of J-C fracture model. Both of the J-C constitutive model and fracture model were employed in numerical simulations and the results was compared with experimental results. The calibrated J-C fracture model exhibits higher accuracy than the J-C fracture model obtained by the common method in predicting the fracture behavior of AA6082-T6. Finally, the Scanning Electron Microscope (SEM) of fractured specimens with different initial stress triaxialities were analyzed. The magnified fractographs indicate that high initial stress triaxiality likely results in dimple fracture.

  18. 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…

  19. Three-Dimensional Numerical Simulation on Triaxial Failure Mechanical Behavior of Rock-Like Specimen Containing Two Unparallel Fissures

    NASA Astrophysics Data System (ADS)

    Huang, Yan-Hua; Yang, Sheng-Qi; Zhao, Jian

    2016-12-01

    A three-dimensional particle flow code (PFC3D) was used for a systematic numerical simulation of the strength failure and cracking behavior of rock-like material specimens containing two unparallel fissures under conventional triaxial compression. The micro-parameters of the parallel bond model were first calibrated using the laboratory results of intact specimens and then validated from the experimental results of pre-fissured specimens under triaxial compression. Numerically simulated stress-strain curves, strength and deformation parameters and macro-failure modes of pre-fissured specimens were all in good agreement with the experimental results. The relationship between stress and the micro-crack numbers was summarized. Crack initiation, propagation and coalescence process of pre-fissured specimens were analyzed in detail. Finally, horizontal and vertical cross sections of numerical specimens were derived from PFC3D. A detailed analysis to reveal the internal damage behavior of rock under triaxial compression was carried out. The experimental and simulated results are expected to improve the understanding of the strength failure and cracking behavior of fractured rock under triaxial compression.

  20. Infinitesimal cranking for triaxial angular-momentum-projected configuration-mixing calculations and its application to the γ vibrational band

    NASA Astrophysics Data System (ADS)

    Tagami, Shingo; Shimizu, Yoshifumi R.

    2016-02-01

    Inclusion of time-odd components into the wave function is important for a reliable description of rotational motion by the angular-momentum-projection method; the cranking procedure with infinitesimal rotational frequency is an efficient way to realize it. In the present work we investigate the effect of this infinitesimal cranking for a triaxially deformed nucleus, where there are three independent cranking axes. It is found that the effects of cranking about three axes on the triaxial energy spectrum are quite different and inclusion of all of them considerably modifies the resultant spectrum from the one obtained without cranking. Employing the Gogny D1S force as an effective interaction, we apply the method to the calculation of the multiple γ vibrational bands in 164Er as a typical example, where the angular-momentum-projected configuration mixing with respect to the triaxial shape degree of freedom is performed. With this method, both the K =0 and the K =4 two-phonon γ vibrational bands are obtained with considerable anharmonicity. Reasonably good agreement, though not perfect, is obtained for both the spectrum and transition probabilities with rather small average triaxial deformation γ ≈9∘ for the ground-state rotational band. The relation to the wobbling motion at high-spin states is also briefly discussed.

  1. An Experimental Method to Determine the Elastic Properties of Transversely Isotropic Rocks by a Single Triaxial Test

    NASA Astrophysics Data System (ADS)

    Togashi, Yota; Kikumoto, Mamoru; Tani, Kazuo

    2017-01-01

    A novel method is proposed for determining the deformation anisotropy of rocks by a single triaxial test using a single specimen sampled from an arbitrary direction. Transversely isotropic elasticity is assumed for the purpose of application of the test method to sedimentary and metamorphic rocks, and the non-axial symmetric stress-strain relationships of anisotropic rocks are determined by triaxial testing by means of a simple improvement to the cap in the triaxial testing apparatus. Both the elastic parameters and the directions of the transversely isotropic elasticity can be obtained by measuring the shear deformations that occur under triaxial stress conditions. An overview of the method for determining transversely isotropic elasticity is presented in this paper, along with the results of a sensitivity analysis performed assuming simulated strains with random measurement errors. The results show that the directions of anisotropy can be determined precisely using the directions of the principal strains measured during isotropic compression and that the elastic parameters can be determined uniquely from the stress-strain relationships observed during both the isotropic and axial compression processes.

  2. Flow and fracture behavior of aluminum alloy 6082-T6 at different tensile strain rates and triaxialities

    PubMed Central

    Chen, Xuanzhen; Peng, Shan; Yao, Song; Chen, Chao; Xu, Ping

    2017-01-01

    This study aims to investigate the flow and fracture behavior of aluminum alloy 6082-T6 (AA6082-T6) at different strain rates and triaxialities. Two groups of Charpy impact tests were carried out to further investigate its dynamic impact fracture property. A series of tensile tests and numerical simulations based on finite element analysis (FEA) were performed. Experimental data on smooth specimens under various strain rates ranging from 0.0001~3400 s-1 shows that AA6082-T6 is rather insensitive to strain rates in general. However, clear rate sensitivity was observed in the range of 0.001~1 s-1 while such a characteristic is counteracted by the adiabatic heating of specimens under high strain rates. A Johnson-Cook constitutive model was proposed based on tensile tests at different strain rates. In this study, the average stress triaxiality and equivalent plastic strain at facture obtained from numerical simulations were used for the calibration of J-C fracture model. Both of the J-C constitutive model and fracture model were employed in numerical simulations and the results was compared with experimental results. The calibrated J-C fracture model exhibits higher accuracy than the J-C fracture model obtained by the common method in predicting the fracture behavior of AA6082-T6. Finally, the Scanning Electron Microscope (SEM) of fractured specimens with different initial stress triaxialities were analyzed. The magnified fractographs indicate that high initial stress triaxiality likely results in dimple fracture. PMID:28759617

  3. Using Tri-Axial Accelerometry in Daily Elite Swim Training Practice.

    PubMed

    Ganzevles, Sander; Vullings, Rik; Beek, Peter Jan; Daanen, Hein; Truijens, Martin

    2017-04-29

    Background: Coaches in elite swimming carefully design the training programs of their swimmers and are keen on achieving strict adherence to those programs by their athletes. At present, coaches usually monitor the compliance of their swimmers to the training program with a stopwatch. However, this measurement clearly limits the monitoring possibilities and is subject to human error. Therefore, the present study was designed to examine the reliability and practical usefulness of tri-axial accelerometers for monitoring lap time, stroke count and stroke rate in swimming. Methods: In the first part of the study, a 1200 m warm-up swimming routine was measured in 13 elite swimmers using tri-axial accelerometers and synchronized video recordings. Reliability was determined using the typical error of measurement (TEM) as well as a Bland-Altman analysis. In the second part, training compliance both within and between carefully prescribed training sessions was assessed in four swimmers in order to determine the practical usefulness of the adopted accelerometric approach. In these sessions, targets were set for lap time and stroke count by the coach. Results: The results indicated high reliability for lap time (TEM = 0.26 s, bias = 0.74 [0.56 0.91] with limits of agreement (LoA) from -1.20 [-1.50 -0.90] to 2.70 [2.40 3.00]), stroke count (TEM 0.73 strokes, bias = 0.46 [0.32 0.60] with LoA from -1.70 [-1.94 -1.46] to 2.60 [2.36 2.84]) and stroke rate (TEM 0.72 str∙min(-1), bias = -0.13 [-0.20 -0.06] with LoA from -2.20 [-2.32 -2.08] to 1.90 [1.78 2.02]), while the results for the monitoring of training compliance demonstrated the practical usefulness of our approach in daily swimming training. Conclusions: The daily training of elite swimmers can be accurately and reliably monitored using tri-axial accelerometers. They provide the coach with more useful information to guide and control the training process than hand-clocked times.

  4. 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

  5. A UNIFIED FRAMEWORK FOR THE ORBITAL STRUCTURE OF BARS AND TRIAXIAL ELLIPSOIDS

    SciTech Connect

    Valluri, Monica; Abbott, Caleb; Shen, Juntai; Debattista, Victor P. E-mail: calebga@umich.edu E-mail: vpdebattista@uclan.ac.uk

    2016-02-20

    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. Microwave ablation with triaxial antennas tuned for lung: results in an in vivo porcine model.

    PubMed

    Durick, Nathan A; Laeseke, Paul F; Broderick, Lynn S; Lee, Fred T; Sampson, Lisa A; Frey, Tina M; Warner, Thomas F; Fine, Jason P; van der Weide, Daniel W; Brace, Christopher L

    2008-04-01

    To prospectively determine in swine the size and shape of coagulation zones created in normal lung tissue by using small-diameter triaxial microwave antennas and to prospectively quantify the effects of bronchial occlusion and multiple antennas on the coagulation zone. The study was approved by the research animal care and use committee, and all husbandry and experimental studies were compliant with the National Research Council's Guide for the Care and Use of Laboratory Animals. Twenty-four coagulation zones (three per animal) were created at thoracotomy in eight female domestic swine (mean weight, 55 kg) by using a microwave ablation system with 17-gauge lung-tuned triaxial antennas. Ablations were performed for 10 minutes each by using (a) a single antenna, (b) a single antenna with bronchial occlusion, and (c) an array of three antennas powered simultaneously. The animals were sacrificed immediately after ablation. The coagulation zones were excised en bloc and sectioned into approximately 4-mm slices for measurement of size, shape, and circularity. Analysis of variance and two-sample t tests were used to identify differences between the three ablation groups. The overall mean diameters of coagulation achieved with a single antenna and bronchial occlusion (4.11 cm +/- 1.09 [standard deviation]) and with multiple-antenna arrays (4.05 cm +/- 0.69) were significantly greater than the overall mean diameter achieved with a single antenna alone (3.09 cm +/- 0.83) (P = .016 for comparison with multiple antennas, P = .032 for comparison with bronchial occlusion). No significant differences in size were seen between the coagulation zones created with bronchial occlusion and those created with multiple antennas (P = .68). The coagulation zones in all groups were very circular (isoperimetric ratio > 0.80) at cross-sectional analysis. A 17-gauge triaxial microwave ablation system tuned for lung tissue yielded large circular zones of coagulation in vivo in porcine lungs

  7. Creation of short microwave ablation zones: in vivo characterization of single and paired modified triaxial antennas.

    PubMed

    Lubner, Meghan G; Ziemlewicz, Tim J; Hinshaw, J Louis; Lee, Fred T; Sampson, Lisa A; Brace, Christopher L

    2014-10-01

    To characterize modified triaxial microwave antennas configured to produce short ablation zones. Fifty single-antenna and 27 paired-antenna hepatic ablations were performed in domestic swine (N = 11) with 17-gauge gas-cooled modified triaxial antennas powered at 65 W 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 and n = 8, respectively) and 10 minutes (n = 7 and n = 5, respectively). Mean transverse width, length, and aspect ratio of sectioned ablation zones were measured and compared. For single antennas, mean ablation zone lengths were 2.9 cm ± 0.45, 3.5 cm ± 0.55, and 4.2 cm ± 0.40 at 2, 5, and 10 minutes, respectively. Mean widths were 1.8 cm ± 0.3, 2.0 cm ± 0.32, and 2.5 cm ± 0.25 at 2, 5, and 10 minutes, respectively. For paired antennas, mean length at 5 minutes with 1-cm and 2-cm spacing and 10 minutes with 1-cm and 2-cm spacing was 4.2 cm ± 0.9, 4.9 cm ± 1.0, 4.8 cm ± 0.5, and 4.8 cm ± 1.3, respectively. Mean width was 3.1 cm ± 1.0, 4.4 cm ± 0.7, 3.8 cm ± 0.4, and 4.5 cm ± 0.7, respectively. Paired-antenna ablations were more spherical (aspect ratios, 0.72-0.79 for 5-10 min) than single-antenna ablations (aspect ratios, 0.57-0.59). For paired-antenna ablations, 1-cm spacing appeared optimal, with improved circularity and decreased clefting compared with 2-cm spacing (circularity, 0.85 at 1 cm, 0.78 at 2 cm). Modified triaxial antennas can generate relatively short, spherical ablation zones. Paired-antenna ablations were rounder and larger in transverse dimension than single antenna ablations, with 1-cm spacing optimal for confluence of the ablation zone. Copyright © 2014 SIR. Published by Elsevier Inc. All rights reserved.

  8. Multispectrum measurements of spectral line parameters including temperature dependences of N2- and self-broadened half-width coefficients in the region of the v9 band of 12C2H6

    SciTech Connect

    Malathy Devi, V.; Benner, D. C.; Rinsland, C.P.; Smith, M.A.H.; Sams, Robert L.; Blake, Thomas A.; Flaud, Jean Marie; Sung, Keeyoon; Brown, L.R.; Mantz, A. W.

    2010-11-01

    Ethane is a prominent contributor to the spectrum of Titan, particularly in the region of the v9 band at 12μm. A multispectrum nonlinear least squares fitting program was applied to laboratory spectra of ethane to measure accurate positions, absolute intensities, N2- and selfbroadened half- width coefficients and their temperature dependences for a large number transitions. These measurements include several pQ and rQ sub-bands (and other sub-bands such as pP, rR) in the v9 fundamental band of 12C2H6 centered near 822 cm-1. Positions were measured for 2958 transitions and intensities for 3771 transitions. N2- and self-broadened half-width coefficients were determined for over 1700 transitions while temperature dependence exponents were retrieved for over 1350 of those transitions. Of these, many measurements (mostly line positions and intensities) belong to the v9+v4-v4 hot band, v9+2v4-2v4 hot band, 13C12CH6 v9 band and unidentified transitions. Forty-three high resolution (0.0016-0.005 cm-1) infrared laboratory absorption spectra recorded at temperatures between 148 and 298 K were fitted simultaneously to retrieve these parameters. Forty-one of these spectra were obtained in the temperature range of 211-298 K using the Bruker IFS 120HR interferometer located at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington. Two additional spectra at 148 K were recorded using a new temperature stabilized cryogenic cell designed to work inside the sample compartment of the high resolution Bruker IFS 125HR interferometer of the Jet Propulsion Laboratory (JPL) in Pasadena California. The specialized cooling cell developed at Connecticut College and capable of achieving gas sample temperatures down to 70 K with a temperature stability and uniformity of better than ±0.05 K was employed to record the 148 K spectra. Constraints to intensity ratios, doublet separations, half-width coefficients and their temperature dependence exponents were required to

  9. Concurrent validity of accelerations measured using a tri-axial inertial measurement unit while walking on firm, compliant and uneven surfaces.

    PubMed

    Cole, Michael H; van den Hoorn, Wolbert; Kavanagh, Justin K; Morrison, Steven; Hodges, Paul W; Smeathers, James E; Kerr, Graham K

    2014-01-01

    Although accelerometers are extensively used for assessing gait, limited research has evaluated the concurrent validity of these devices on less predictable walking surfaces or the comparability of different methods used for gravitational acceleration compensation. This study evaluated the concurrent validity of trunk accelerations derived from a tri-axial inertial measurement unit while walking on firm, compliant and uneven surfaces and contrasted two methods used to remove gravitational accelerations; i) subtraction of the best linear fit from the data (detrending); and ii) use of orientation information (quaternions) from the inertial measurement unit. Twelve older and twelve younger adults walked at their preferred speed along firm, compliant and uneven walkways. Accelerations were evaluated for the thoracic spine (T12) using a tri-axial inertial measurement unit and an eleven-camera Vicon system. The findings demonstrated excellent agreement between accelerations derived from the inertial measurement unit and motion analysis system, including while walking on uneven surfaces that better approximate a real-world setting (all differences <0.16 m.s(-2)). Detrending produced slightly better agreement between the inertial measurement unit and Vicon system on firm surfaces (delta range: -0.05 to 0.06 vs. 0.00 to 0.14 m.s(-2)), whereas the quaternion method performed better when walking on compliant and uneven walkways (delta range: -0.16 to -0.02 vs. -0.07 to 0.07 m.s(-2)). The technique used to compensate for gravitational accelerations requires consideration in future research, particularly when walking on compliant and uneven surfaces. These findings demonstrate trunk accelerations can be accurately measured using a wireless inertial measurement unit and are appropriate for research that evaluates healthy populations in complex environments.

  10. On the Elasto-Plastic Response of a Large-Tow Triaxial Braided Composite

    SciTech Connect

    Zywicz, E.; O'Brien, M.J.; Nguyen, T.

    2000-06-14

    The elastic-plastic response of a large-tow 0{sup o}/{+-}{theta}{sup o} tri-axially braided composite is numerically simulated to determine the elastic coefficients and post-yield behavior. The ratios of extensional to flexural effective Young's moduli vary from 0.30 to 0.52 in the longitudinal direction and 0.90 to 0.95 in the transverse direction. Measurements on a 2-ply 0{sup o}/{+-} 30{sup o} braid support these numerical trends. The onset of macro yield in uniaxial extension coincides with the experimental values in the longitudinal direction while it is nearly twice the experimental values in the transverse direction. In simple shear, matrix plasticity around the undulations facilitates local rotation of the braiders at the onset of macro yield. Under uniaxial flexure, modest stiffening occurs prior to strain softening in both the principal directions.

  11. Northern boundary of the ;island of inversion; and triaxiality in 34Si

    NASA Astrophysics Data System (ADS)

    Han, R.; Li, X. Q.; Jiang, W. G.; Li, Z. H.; Hua, H.; Zhang, S. Q.; Yuan, C. X.; Jiang, D. X.; Ye, Y. L.; Li, J.; Li, Z. H.; Xu, F. R.; Chen, Q. B.; Meng, J.; Wang, J. S.; Xu, C.; Sun, Y. L.; Wang, C. G.; Wu, H. Y.; Niu, C. Y.; Li, C. G.; He, C.; Jiang, W.; Li, P. J.; Zang, H. L.; Feng, J.; Chen, S. D.; Liu, Q.; Chen, X. C.; Xu, H. S.; Hu, Z. G.; Yang, Y. Y.; Ma, P.; Ma, J. B.; Jin, S. L.; Bai, Z.; Huang, M. R.; Zhou, Y. J.; Ma, W. H.; Li, Y.; Zhou, X. H.; Zhang, Y. H.; Xiao, G. Q.; Zhan, W. L.

    2017-09-01

    β-decay studies of neutron-rich nuclei in and around the "island of inversion" have been performed. With a systematic investigation of half-lives for the isotonic chains from N = 19 to 22, conspicuous kinks observed at Z = 13 provide a clear signature of a boundary on the northern (high-Z) side of the island. Based on the comparison with shell model calculations using Gogny D1S and SDPF-M interactions, a newly determined 22+ state in 34Si at 4519 keV presents an experimental evidence of triaxiality in this region and sheds more light on the structure of the transition across the northern boundary of the island.

  12. Impact of Triaxiality on the Structure of Neutron-Rich Rhenium Isotopes

    SciTech Connect

    Reed, M. W.; Lane, G. L.; Dracoulis, G. D.; Kondev, F. G.; Carpenter, M. P.; Chowdhury, P.; Hota, S. S.; Hughes, R. O.; Janssens, R. V. F.; Lauritsen, T.; Lister, C. J.; Palalani, N; Seweryniak, D.; Watanabe, H.; Zhu, S.; Jiang, W.G.; Xu, F.R.

    2016-01-10

    A number of 3-quasiparticle isomers have been found and characterised in the odd-mass, neutron-rich, Re-187, Re-189 and Re-191 nuclei, the latter being four neutrons beyond stability. The decay of the isomers populates states in the rotational bands built upon the 9/2(-)[514] Nilsson orbital. These bands exhibit a degree of signature splitting that increases with neutron number. This splitting taken together with measurements of the M1/E2 mixing ratios and with the changes observed in the energy of the gamma-vibrational band coupled to the 9/2(-)[514] state, suggests an increase in triaxiality, with gamma values of 5 degrees, 18 degrees and 25 degrees deduced in the framework of a particle-rotor model. (C) 2015 Published by Elsevier B.V.

  13. The Fracture Characteristic of Three Collinear Cracks under True Triaxial Compression

    PubMed Central

    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

  14. 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.

  15. 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

  16. Void growth and coalescence in triaxial stress fields in irradiated FCC single crystals

    NASA Astrophysics Data System (ADS)

    Ling, Chao; Tanguy, Benoît; Besson, Jacques; Forest, Samuel; Latourte, Felix

    2017-08-01

    Void growth and coalescence, known as main mechanisms of ductile fracture, are investigated for irradiated FCC single crystals. Finite element simulations of voided unit cells are performed with a single crystal plasticity model accounting for strain hardening and softening associated with irradiation-induced defects. The simulations predict a rather brittle overall behavior for the voided irradiated single crystal at high stress triaxiality, with a large amount of local plastic deformation, which is consistent with experimental observations reported in the literature for stainless steels irradiated in fast reactors. Compared with unirradiated single crystals, irradiated crystals exhibit a higher void growth rate leading to an earlier void coalescence, which is caused by a stronger plastic slip localization in the region near the voids.

  17. Experimental Observations of Localization Phenomena in Sands: Plane Strain Versus Triaxial Compression Conditions

    NASA Technical Reports Server (NTRS)

    Alshibli, Khalid A.; Batiste, Susan N.; Sture, Stein; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    A comprehensive experimental investigation was conducted to investigate the effects of loading condition and confining pressure on strength properties and instability phenomena in sands. A uniform sub-rounded to rounded natural silica sand known as F-75 Ottawa sand was used in the investigation. The results of a series on Conventional Triaxial Compression (CTC) experiments tested under very low confining pressures (0.05 - 1.30) kPa tested in a Microgravity environment abroad the NASA Space Shuttle are presented in addition to the results similar specimens tested in terrestrial laboratory to investigate the effect of confining pressure on the constitutive behavior of sands. The behavior of the CTC experiments is compared with the results of Plane Strain (PS) experiments. Computed tomography and other digital imaging techniques were used to study the development and evolution of shear bands.

  18. Assessment of the Mechanical Properties of Sisal Fiber-Reinforced Silty Clay Using Triaxial Shear Tests

    PubMed Central

    Wu, Yankai; Li, Yanbin; Niu, Bin

    2014-01-01

    Fiber reinforcement is widely used in construction engineering to improve the mechanical properties of soil because it increases the soil's strength and improves the soil's mechanical properties. However, the mechanical properties of fiber-reinforced soils remain controversial. The present study investigated the mechanical properties of silty clay reinforced with discrete, randomly distributed sisal fibers using triaxial shear tests. The sisal fibers were cut to different lengths, randomly mixed with silty clay in varying percentages, and compacted to the maximum dry density at the optimum moisture content. The results indicate that with a fiber length of 10 mm and content of 1.0%, sisal fiber-reinforced silty clay is 20% stronger than nonreinforced silty clay. The fiber-reinforced silty clay exhibited crack fracture and surface shear fracture failure modes, implying that sisal fiber is a good earth reinforcement material with potential applications in civil engineering, dam foundation, roadbed engineering, and ground treatment. PMID:24982951

  19. 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 (

  20. 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.

  1. Effect of a triaxial nuclear shape on proton tunneling: the decay and structure of 145Tm.

    PubMed

    Seweryniak, D; Blank, B; Carpenter, M P; Davids, C N; Davinson, T; Freeman, S J; Hammond, N; Hoteling, N; Janssens, R V F; Khoo, T L; Liu, Z; Mukherjee, G; Robinson, A; Scholey, C; Sinha, S; Shergur, J; Starosta, K; Walters, W B; Woehr, A; Woods, P J

    2007-08-24

    Gamma rays deexciting states in the proton emitter 145Tm were observed using the recoil-decay tagging method. The 145Tm ground-state rotational band was found to exhibit the properties expected for an h{11/2} proton decoupled band. In addition, coincidences between protons feeding the 2{+} state in 144Er and the 2{+}-->0{+} gamma-ray transition were detected, the first measurement of this kind, leading to a more precise value for the 2{+} excitation energy of 329(1) keV. Calculations with the particle-rotor model and the core quasiparticle coupling model indicate that the properties of the pi{11/2} band and the proton-decay rates in 145Tm are consistent with the presence of triaxiality with an asymmetry parameter gamma approximately 20 degrees .

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

    PubMed

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

    2016-04-17

    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.

  3. Assessment of the mechanical properties of sisal fiber-reinforced silty clay using triaxial shear tests.

    PubMed

    Wu, Yankai; Li, Yanbin; Niu, Bin

    2014-01-01

    Fiber reinforcement is widely used in construction engineering to improve the mechanical properties of soil because it increases the soil's strength and improves the soil's mechanical properties. However, the mechanical properties of fiber-reinforced soils remain controversial. The present study investigated the mechanical properties of silty clay reinforced with discrete, randomly distributed sisal fibers using triaxial shear tests. The sisal fibers were cut to different lengths, randomly mixed with silty clay in varying percentages, and compacted to the maximum dry density at the optimum moisture content. The results indicate that with a fiber length of 10 mm and content of 1.0%, sisal fiber-reinforced silty clay is 20% stronger than nonreinforced silty clay. The fiber-reinforced silty clay exhibited crack fracture and surface shear fracture failure modes, implying that sisal fiber is a good earth reinforcement material with potential applications in civil engineering, dam foundation, roadbed engineering, and ground treatment.

  4. A table-shaped tactile sensor for detecting triaxial force on the basis of strain distribution.

    PubMed

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

    2013-11-28

    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.

  5. 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.

  6. Critical point symmetry for the spherical to triaxially deformed shape phase transition

    NASA Astrophysics Data System (ADS)

    Zhang, Yu; Pan, Feng; Luo, Yan-An; Draayer, J. P.

    2015-12-01

    The critical point T(5) symmetry for the spherical to triaxially deformed shape phase transition is introduced from the Bohr Hamiltonian by approximately separating variables at a given γ deformation with 0 ° ≤ γ ≤ 30 °. The resulting spectral and E2 properties have been investigated in detail. The results indicate that the original X(5) and Z(5) critical point symmetries can be naturally realized within the T(5) model in the γ = 0 ° and γ = 30 ° limit, respectively, which thus provides a dynamical connection between the two symmetries. Comparison of the theoretical calculations for 148Ce, 160Yb, 192Pt and 194Pt with the corresponding experimental data is also made, which indicates that, to some extent, possible asymmetric deformation may be involved in these transitional nuclei.

  7. Permeability of Triaxially Compressed Sandstone: Influence of Deformation and Strain-rate on Permeability

    NASA Astrophysics Data System (ADS)

    Heiland, J.

    - The influence of differential stress on the permeability of a Lower Permian sandstone was investigated. Rock cylinders of 50 mm in diameter and 100 mm length of a fine-grained (mean grain size 0.2 mm), low-porosity (6-9%) sandstone were used to study the relation between differential stress, rock deformation, rock failure and hydraulic properties, with a focus on the changes of hydraulic properties in the pre-failure and failure region of triaxial rock deformation. The experiments were conducted at confining pressures up to 20 MPa, and axial force was controlled by lateral strain with a rate ranging from 10-6 to 10-7 sec-1. While deforming the samples, permeability was determined by steady-state technique with a pressure gradient of 1 MPa over the specimen length and a fluid pressure level between 40 and 90% of the confining pressure. The results show that permeability of low-porosity sandstones under increasing triaxial stress firstly decreases due to compaction and starts to increase after the onset of dilatancy. This kind of permeability evolution is similar to that of crystalline rocks. A significant dependence of permeability evolution on strain rate was found. Comparison of permeability to volumetric strain demonstrates that the permeability increase after the onset of dilatancy is not sufficient to regain the initial permeability up to failure of the specimen. The initial permeability, which was determined in advance of the experiments, usually was regained in the post-failure region. After the onset of dilatancy, the permeability increase displays a linear dependence on volumetric strain.

  8. Evaluation of Instability Phenomena in Sands: Plane Strain Versus Triaxial Conditions

    NASA Technical Reports Server (NTRS)

    Alshibli, Khalid A.

    2001-01-01

    Extensive research was carried out in the 1950s on theories of plasticity to extend the concepts developed for metals to materials that failed according to the Mohr-Coulomb criterion. The new ideas made it possible to merge the two distinct concepts (strength and deformation techniques) into one that relies on better understanding of plasticity and resulted in a rapid growth in the field of constitutive modeling of soil behavior. At the same time advanced experimental apparatuses and laboratory procedures were developed to calibrate the models. However, most laboratory experiments on granular materials are performed under Conventional Triaxial Conditions (CTC) for the purposes of evaluating constitutive behavior and stability properties, whereas most geotechnical field problems are closer to the Plane Strain (PS) condition. The triaxial tests performed in most laboratories comprise a simplification over in situ states and allow easier and robust experimentation. Most landslide problems, failure of soils beneath shallow and deep foundations, and failure of retaining structures, are cases that can generally be considered as plane strain. Strength and deformation characteristics of granular materials loaded in plane strain may be considerably different from those observed in CTC. Most studies on sands were limited to evaluating the constitutive behavior and in some cases extended to briefly describing the associated instability phenomena. This paper presents the results of a series of PS and CTC experiments performed on fine uniform silica sand known as F-75 Ottawa sand. Advanced analysis techniques were used to study the instability phenomena, which yielded very accurate measurements of shear bands occurrences and patterns. Destructive thin-sectioning technique along with monitoring the specimen surface deformation was used in the PS experiments and Computed Tomography (CT) was used to investigate the progress of primary and secondary shear bands in specimens

  9. Evolution of dilatancy and permeability in rock salt during hydrostatic compaction and triaxial deformation

    NASA Astrophysics Data System (ADS)

    Popp, Till; Kern, Hartmut; Schulze, Otto

    2001-01-01

    Combined gas permeability and P and S wave velocity measurements were carried out on rock salt samples from the Gorleben salt dome and the Morsleben salt mine under hydrostatic and triaxial loading condions, mostly at room temperature. Permeabilities in the as-received samples vary between 10-16 and 2×10-20 m2. The initial permeability is primarily due to decompaction induced by drilling, core retrieval and sample preparation. Hydrostatic loading gives rise to a marked decrease of permeability and a coeval significant increase of P and S wave velocities due to progressive closure of grain boundary cracks, tending to approach the in situ matrix permeability (<10-20 m2). The pore space sensitivity of P and S wave velocities is used to monitor the in situ state of the microstructure. Their reversals define the boundary in the state of stresses between dilatant and compactive domains (dilatancy boundary). Dilatancy during triaxial deformation of the compacted rock salt samples is found to evolve stress dependent in various stages. The crack initiation stress increases from ˜18 MPa differential stress at 10 MPa confining pressure to ˜30 MPa at confining pressures above ˜70 MPa. Dilatancy is due to the opening of grain boundary and (100) cleavage cracks and depends on the applied confining pressure. The orientation of the open cracks is primarily controlled by the loading geometry system (compression, extension). As a consequence, permeability increases dramatically with progressive dilatancy, followed by a period of plus/minus constant permeability during strain hardening up to 10% axial strain or even more. This suggests that the evolution of permeability is not only a function of dilatancy but also of microcrack linkage. Importantly, the anisotropic crack array within the samples causes a strong directional dependence of permeability.

  10. Quantitative assessment of walking time and postural change in patients with COPD using a new triaxial accelerometer system.

    PubMed

    Kawagoshi, Atsuyoshi; Kiyokawa, Noritaka; Sugawara, Keiyu; Takahashi, Hitomi; Sakata, Shunichi; Miura, Saori; Sawamura, Sachie; Satake, Masahiro; Shioya, Takanobu

    2013-01-01

    The purpose of this study was to quantify the walking time and frequency of postural changes in daily life in patients with chronic obstructive pulmonary disease (COPD) using a new triaxial accelerometer system. Twenty-six elderly patients with stable COPD (age 76.8 ± 6.2 years; percent forced expiratory volume in one second [%FEV1] 52.9% ± 26.3%) and 20 age-matched elderly subjects (age 73.0 ± 4.2 years; %FEV1 124.0% ± 22.3%) participated in the study. The subjects' time spent walking (slow, fast), standing, sitting, and lying down and the frequency of their postural changes (getting up, standing up) were assessed for 7 consecutive days using an Activity Monitoring And Evaluation System (A-MES™). We analyzed the relationships among walking times, frequency of postural changes, and physiologic factors in both COPD patients and controls. The COPD patients' total walking time, including slow (<2 km/hour) and fast (≥2 km/hour) walking, and their frequency of standing up were significantly lower than those of the age-matched controls (P < 0.01). The fast walking time in daily life was significantly correlated with the 6-minute walking distance, quadriceps femoris muscle force, and dyspnea (P < 0.01). These results suggest that both slow (<2 km/hour) and fast (≥2 km/hour) walking time and frequency of postural changes is significantly decreased in COPD patients compared with healthy elderly subjects. The data also suggest that the COPD patients' different walking times in daily life are significantly correlated with exercise capacity and dyspnea. The 6-minute walking distance had the strongest correlation with fast walking time.

  11. Validity of Using Tri-Axial Accelerometers to Measure Human Movement - Part I: Posture and Movement Detection

    PubMed Central

    Lugade, Vipul; Fortune, Emma; Morrow, Melissa; Kaufman, Kenton

    2013-01-01

    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

  12. Experimental Study of Remotely Triggered Rockburst Induced by a Tunnel Axial Dynamic Disturbance Under True-Triaxial Conditions

    NASA Astrophysics Data System (ADS)

    Su, Guoshao; Feng, Xiating; Wang, Jinhuan; Jiang, Jianqing; Hu, Lihua

    2017-08-01

    During deep underground excavation, dynamic ejection failure of a highly stressed rock mass near an excavated boundary is easily triggered by a dynamic disturbance in the tunnel axial direction, induced by blasting on the tunnel face. Such a dynamic ejection failure is usually called remotely triggered rockburst, and it poses a threat to underground construction. To clarify the characteristics of remotely triggered rockburst, the development of remotely triggered rockbursts of granite rock specimens was investigated using an improved true-triaxial test system. Experimental results show that with increasing static Z-direction stress (i.e., in situ tangential stress on the cross section of the tunnel), rockburst is triggered more easily and the kinetic energy of ejected fragments increases. Under other constant static stresses and dynamic disturbance, with increasing horizontal stress including X-direction stress (i.e., in situ axial stress) or Y-direction stress (i.e., in situ radial stress on the cross section of the tunnel), rockburst is more difficult to trigger and the kinetic energy of the ejected fragments decreases. Under constant static stresses, once the amplitude and frequency of the dynamic loading exceed their thresholds, the rockburst intensity increases rapidly and the rockburst can be triggered much more easily with small increments of the amplitude and frequency. Furthermore, Z-direction strain increases during the dynamic disturbance process, indicating that the ultimate energy-storage capacity of the specimen decreases with increasing damage. When the elastic strain energy is greater than the ultimate energy-storage capacity of the damaged specimen, part of the residual elastic energy is converted into kinetic energy of the ejected fragments.

  13. 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.

  14. High-spin level structure of {sup 115}Rh: Evolution of triaxiality in odd-even Rh isotopes

    SciTech Connect

    Liu, S. H.; Gelberg, A.; Gu, L.; Yeoh, E. Y.; Zhu, S. J.; Luo, Y. X.; Rasmussen, J. O.; Ma, W. C.; Daniel, A. V.; Oganessian, Yu. Ts.; Ter-Akopian, G. M.

    2011-07-15

    High-spin excited states in the neutron-rich nucleus {sup 115}Rh have been identified for the first time by studying prompt {gamma} rays from the spontaneous fission of {sup 252}Cf with the Gammasphere detector array. A new yrast band and a sideband are built in {sup 115}Rh. This level scheme is proposed to be built on the 7/2{sup +} ground state. The existence of a large signature splitting and an yrare band in {sup 115}Rh shows typical features of a triaxially deformed nucleus. The rigid triaxial rotor plus particle model is used to interpret the level structure of {sup 115}Rh. The level energies, the {gamma} branching ratios, the large signature splitting in the yrast band, and the inverted signature splitting in the yrare band in {sup 115}Rh are reproduced very well. Strong K mixing occurs in {sup 115}Rh at high spin.

  15. Taguchi design and flower pollination algorithm application to optimize the shrinkage of triaxial porcelain containing palm oil fuel ash

    NASA Astrophysics Data System (ADS)

    Zainudin, A.; Sia, C. K.; Ong, P.; Narong, O. L. C.; Nor, N. H. M.

    2017-01-01

    In the preparation of triaxial porcelain from Palm Oil Fuel Ash (POFA), a new parameter variable must be determined. The parameters involved are the particle size of POFA, percentage of POFA in triaxial porcelain composition, moulding pressure, sintering temperature and soaking time. Meanwhile, the shrinkage is the dependent variable. The optimization process was investigated using a hybrid Taguchi design and flower pollination algorithm (FPA). The interaction model of shrinkage was derived from regression analysis and found that the shrinkage is highly dependent on the sintering temperature followed by POFA composition, moulding pressure, POFA particle size and soaking time. The interaction between sintering temperature and soaking time highly affects the shrinkage. From the FPA process, targeted shrinkage approaching zero values were predicted for 142 μm particle sizes of POFA, 22.5 wt% of POFA, 3.4 tonne moulding pressure, 948.5 °C sintering temperature and 264 minutes soaking time.

  16. COVOL: an interactive program for evaluating second virial coefficients from the triaxial shape or dimensions of rigid macromolecules.

    PubMed Central

    Harding, S E; Horton, J C; Jones, S; Thornton, J M; Winzor, D J

    1999-01-01

    An interactive program is described for calculating the second virial coefficient contribution to the thermodynamic nonideality of solutions of rigid macromolecules based on their triaxial dimensions. The FORTRAN-77 program, available in precompiled form for the PC, is based on theory for the covolume of triaxial ellipsoid particles [Rallison, J. M., and S.E Harding. (1985). J. Colloid Interface Sci. 103:284-289]. This covolume has the potential to provide a magnitude for the second virial coefficient of macromolecules bearing no net charge. Allowance for a charge-charge contribution is made via an expression based on Debye-Hückel theory and uniform distribution of the net charge over the surface of a sphere with dimensions governed by the Stokes radius of the macromolecule. Ovalbumin, ribonuclease A, and hemoglobin are used as model systems to illustrate application of the COVOL routine. PMID:10233060

  17. Modified particle-rotor model and low-lying rotational bands in odd-A triaxial nuclei

    NASA Astrophysics Data System (ADS)

    Modi, Swati; Patial, M.; Arumugam, P.; Maglione, E.; Ferreira, L. S.

    2017-09-01

    The low-lying rotational bands of triaxially deformed nuclei 137Pr, 137Pm and 139Eu are studied with a modified particle-rotor model following the nonadiabatic quasiparticle approach. The matrix elements of the odd-A nucleus are obtained in terms of a coupling matrix and the rotational energies of the even-even core. The spectra of the cores 136Ce, 136Nd and 138Sm indicate a strong influence of triaxial deformation and vibrational degrees of freedom. These properties are appropriately carried forward to the calculations for the odd-A nucleus. We demonstrate that the ground and side bands of the odd-A nucleus and its core can be explained with the same set of deformation parameters ({β }2, γ). We argue that this method could be useful in studying the low-lying states in exotic nuclei also.

  18. 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

  19. Triaxial quadrupole dynamics and the inner fission barrier of some heavy even-even nuclei

    NASA Astrophysics Data System (ADS)

    Benrabia, K.; Medjadi, D. E.; Imadalou, M.; Quentin, P.

    2017-09-01

    Background: Inner fission barriers of actinide nuclei have been known for a long time to be unstable with respect to the axial symmetry. On the other hand, taking into account the effect of the relevant adiabatic mass parameter reduces or even may wash out this instability. A proper treatment of the dynamics for both axial and triaxial modes is thus crucial to accurately determine the corresponding fission barriers. This entails in particular an accurate description of pairing correlations. Purpose: We evaluate the potential energies, moments of inertia, and vibrational mass parameters in a two-dimensional relevant deformation space (corresponding to the usual β and γ quadrupole deformation parameters) for four actinide nuclei (236U, 240Pu, 248Cm, and 252Cf). We assess the relevance of our approach to describe the dynamics for a triaxial mode by computing the low energy spectra (exploring thus mainly the equilibrium deformation region). We evaluate the inner fission barrier heights releasing the axial symmetry constraint. Method: Calculations within the Hartree-Fock plus BCS approach are performed using the SkM* Skyrme effective interaction in the particle-hole channel and a seniority force in the particle-particle channel. The intensity of this residual interaction has been fixed to allow a good reproduction of some odd-even mass differences in the actinide region. Adiabatic mass parameters for the rotational and vibrational modes are calculated using the Inglis-Belyaev formula supplemented by a global renormalization factor taking into account the so-called Thouless-Valatin corrections. Spectra are obtained through the diagonalization of the corresponding Bohr collective Hamiltonian. Results: The experimental low energy spectra are qualitatively well reproduced by our calculations for the considered nuclei. Inner fission barrier heights are calculated and compared with available estimates from various experimental data. The reproduction of the data is better

  20. The Effects of Hygrothermal Aging on the Impact Penetration Resistance of Triaxially Braided Composites

    NASA Technical Reports Server (NTRS)

    Pereira, J. Michael; Revilock, Duane M.; Ruggeri, Charles R.; Roberts, Gary D.; Kohlman, Lee W.; Miller, Sandi G.

    2016-01-01

    An experimental study was conducted to measure the effects of long term hygrothermal aging on the impact penetration resistance of triaxially braided polymer composites. Flat panels of three different materials were subjected to repeated cycles of high and low temperature and high and low humidity for two years. Samples of the panels were periodically tested under impact loading during the two year time period. The purpose of the study was to identify and quantify any degradation in impact penetration resistance of these composites under cyclic temperature and humidity conditions experienced by materials in the fan section of commercial gas turbine engines for a representative aircraft flight cycle. The materials tested consisted of Toray ® T700S carbon fibers in a 2D triaxial braid with three different resins, Cycom® PR520, a toughened resin, Hercules® 3502, an untoughened resin and EPON 862, intermediate between the two. The fiber preforms consisted of a quasi-isotropic 0/+60/-60 braid with 24K tows in the axial direction and 12K tows in the bias directions. The composite panels were manufactured using a resin transfer molding process producing panels with a thickness of 0.125 inches. The materials were tested in their as-processed condition and again after one year and two years of aging (1.6 years in the case of E862). The aging process involved subjecting the test panels to two cycles per day of high and low temperature and high and low humidity. A temperature range of -60degF to 250degF and a humidity range of 0 to 85% rh was used to simulate extreme conditions for composite components in the fan section of a commercial gas turbine engine. Additional testing was conducted on the as-processed PR520 composite under cryogenic conditions. After aging there was some change in the failure pattern, but there was no reduction in impact penetration threshold for any of the three systems, and in the case of the 3502 system, a significant increase in penetration

  1. 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

  2. Real-time estimation of daily physical activity intensity by a triaxial accelerometer and a gravity-removal classification algorithm.

    PubMed

    Ohkawara, Kazunori; Oshima, Yoshitake; Hikihara, Yuki; Ishikawa-Takata, Kazuko; Tabata, Izumi; Tanaka, Shigeho

    2011-06-01

    We have recently developed a simple algorithm for the classification of household and locomotive activities using the ratio of unfiltered to filtered synthetic acceleration (gravity-removal physical activity classification algorithm, GRPACA) measured by a triaxial accelerometer. The purpose of the present study was to develop a new model for the immediate estimation of daily physical activity intensities using a triaxial accelerometer. A total of sixty-six subjects were randomly assigned into validation (n 44) and cross-validation (n 22) groups. All subjects performed fourteen activities while wearing a triaxial accelerometer in a controlled laboratory setting. During each activity, energy expenditure was measured by indirect calorimetry, and physical activity intensities were expressed as metabolic equivalents (MET). The validation group displayed strong relationships between measured MET and filtered synthetic accelerations for household (r 0·907, P < 0·001) and locomotive (r 0·961, P < 0·001) activities. In the cross-validation group, two GRPACA-based linear regression models provided highly accurate MET estimation for household and locomotive activities. Results were similar when equations were developed by non-linear regression or sex-specific linear or non-linear regressions. Sedentary activities were also accurately estimated by the specific linear regression classified from other activity counts. Therefore, the use of a triaxial accelerometer in combination with a GRPACA permits more accurate and immediate estimation of daily physical activity intensities, compared with previously reported cut-off classification models. This method may be useful for field investigations as well as for self-monitoring by general users.

  3. The validity of gait variability and fractal dynamics obtained from a single, body-fixed triaxial accelerometer.

    PubMed

    Kobsar, Dylan; Olson, Chad; Paranjape, Raman; Barden, John M

    2014-04-01

    A single triaxial accelerometer has the ability to collect a large amount of continuous gait data to quantitatively assess the control of gait. Unfortunately, there is limited information on the validity of gait variability and fractal dynamics obtained from this device. The purpose of this study was to test the concurrent validity of the variability and fractal dynamic measures of gait provided by a triaxial accelerometer during a continuous 10 minute walk in older adults. Forty-one healthy older adults were fitted with a single triaxial accelerometer at the waist, as well as a criterion footswitch device before completing a ten minute overground walk. The concurrent validity of six outcome measures was examined using intraclass correlation coefficients (ICC) and 95% limits of agreement. All six dependent variables measured by the accelerometer displayed excellent agreement with the footswitch device. Mean parameters displayed the highest validity, followed by measures of variability and fractal dynamics in stride times and measures of variability and fractal dynamics in step times. These findings suggest that an accelerometer is a valid and unique device that has the potential to provide clinicians with valid quantitative data for assessing their clients' gait.

  4. 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.

  5. In-line SPE-CE using a fritless bead string design--application for the analysis of organic sulfonates including inline SPE-CE-MS for APTS-labeled glycans.

    PubMed

    Jooß, Kevin; Sommer, Johannes; Bunz, Svenja-Catharina; Neusüß, Christian

    2014-05-01

    Despite many advantages like high separation efficiency CE comprises the main limitation of low concentration sensitivity, when compared to HPLC. In-line SPE is an efficient way to increase concentration sensitivity. Here, a fritless in-line-SPE-CE-MS method was developed in order to analyze anions of strong acids. Mixed-mode (weak anion exchange and RP) particles were used for enrichment and an acidic BGE was applied for separation. Different particle and capillary sizes were tested. A novel bead string design with a 100 μm id column filled with particles of 90 μm followed by a separation capillary with 50 μm id was easy to prepare and showed the best performance with respect to separation efficiency and reproducibility. Three aromatic sulfonic acids were employed in an in-line SPE-CE-UV approach for method development. Method validation was performed with respect to reproducibility, robustness, and linearity. Thereafter the method was transferred to SPE-CE-MS and applied to the analysis of glycans labeled with 8-aminopyrene-1,3,6-trisulfonic acid. Lower limits of detection in the low nM range were achieved injecting about 10 μL of sample. This corresponds to an enrichment factor of more than 800 compared to the corresponding CE-MS method without preconcentration. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. A Missile-Borne Angular Velocity Sensor Based on Triaxial Electromagnetic Induction Coils

    PubMed Central

    Li, Jian; Wu, Dan; Han, Yan

    2016-01-01

    Aiming to solve the problem of the limited measuring range for angular motion parameters of high-speed rotating projectiles in the field of guidance and control, a self-adaptive measurement method for angular motion parameters based on the electromagnetic induction principle is proposed. First, a framework with type bent “I-shape” is used to design triaxial coils in a mutually orthogonal way. Under the condition of high rotational speed of a projectile, the induction signal of the projectile moving across a geomagnetic field is acquired by using coils. Second, the frequency of the pulse signal is adjusted self-adaptively. Angular velocity and angular displacement are calculated in the form of periodic pulse counting and pulse accumulation, respectively. Finally, on the basis of that principle prototype of the sensor is researched and developed, performance of measuring angular motion parameters are tested on the sensor by semi-physical and physical simulation experiments, respectively. Experimental results demonstrate that the sensor has a wide measuring range of angular velocity from 1 rps to 100 rps with a measurement error of less than 0.3%, and the angular displacement measurement error is lower than 0.2°. The proposed method satisfies measurement requirements for high-speed rotating projectiles with an extremely high dynamic range of rotational speed and high precision, and has definite value to engineering applications in the fields of attitude determination and geomagnetic navigation. PMID:27706039

  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. MEMS-Based Flexible Force Sensor for Tri-Axial Catheter Contact Force Measurement.

    PubMed

    Pandya, Hardik J; Sheng, Jun; Desai, Jaydev P

    2017-02-01

    Atrial fibrillation (AFib) is a significant healthcare problem caused by the uneven and rapid discharge of electrical signals from pulmonary veins (PVs). The technique of radiofrequency (RF) ablation can block these abnormal electrical signals by ablating myocardial sleeves inside PVs. Catheter contact force measurement during RF ablation can reduce the rate of AFib recurrence, since it helps to determine effective contact of the catheter with the tissue, thereby resulting in effective power delivery for ablation. This paper presents the development of a three-dimensional (3D) force sensor to provide the real-time measurement of tri-axial catheter contact force. The 3D force sensor consists of a plastic cubic bead and five flexible force sensors. Each flexible force sensor was made of a PEDOT:PSS strain gauge and a PDMS bump on a flexible PDMS substrate. Calibration results show that the fabricated sensor has a linear response in the force range required for RF ablation. To evaluate its working performance, the fabricated sensor was pressed against gelatin tissue by a micromanipulator and also integrated on a catheter tip to test it within deionized water flow. Both experiments simulated the ventricular environment and proved the validity of applying the 3D force sensor in RF ablation.

  9. 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.

  10. Using tri-axial accelerometers to identify wild polar bear behaviors

    USGS Publications Warehouse

    Pagano, Anthony M.; Rode, Karyn D.; Cutting, A.; Owen, M.A.; Jensen, S.; Ware, J.V.; Robbins, C.T.; Durner, George M.; Atwood, Todd C.; Obbard, M.E.; Middel, K.R.; Thiemann, G.W.; Williams, T.M.

    2017-01-01

    Tri-axial accelerometers have been used to remotely identify the behaviors of a wide range of taxa. Assigning behaviors to accelerometer data often involves the use of captive animals or surrogate species, as their accelerometer signatures are generally assumed to be similar to those of their wild counterparts. However, this has rarely been tested. Validated accelerometer data are needed for polar bears Ursus maritimus to understand how habitat conditions may influence behavior and energy demands. We used accelerometer and water conductivity data to remotely distinguish 10 polar bear behaviors. We calibrated accelerometer and conductivity data collected from collars with behaviors observed from video-recorded captive polar bears and brown bears U. arctos, and with video from camera collars deployed on free-ranging polar bears on sea ice and on land. We used random forest models to predict behaviors and found strong ability to discriminate the most common wild polar bear behaviors using a combination of accelerometer and conductivity sensor data from captive or wild polar bears. In contrast, models using data from captive brown bears failed to reliably distinguish most active behaviors in wild polar bears. Our ability to discriminate behavior was greatest when species- and habitat-specific data from wild individuals were used to train models. Data from captive individuals may be suitable for calibrating accelerometers, but may provide reduced ability to discriminate some behaviors. The accelerometer calibrations developed here provide a method to quantify polar bear behaviors to evaluate the impacts of declines in Arctic sea ice.

  11. 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.

  12. Gallery of melt textures developed in Westerly Granite during high-pressure triaxial friction experiments

    USGS Publications Warehouse

    Moore, Diane E.; Lockner, David A.; Kilgore, Brian D.; Beeler, Nicholas M.

    2016-09-23

    IntroductionMelting occurred during stick-slip faulting of granite blocks sheared at room-dry, room-temperature conditions in a triaxial apparatus at 200–400 megapascals (MPa) confining pressure. Petrographic examinations of melt textures focused largely on the 400-MPa run products. This report presents an overview of the petrographic data collected on those samples, followed by brief descriptions of annotated versions of all the images.Scanning electron microscope (SEM) images of the starting materials and the three examined 400-MPa samples are presented in this report. Secondary-electron (SE) and backscattered-electron (BSE) imaging techniques were used on different samples. The SE images look down on the sawcut surfaces, yielding topographic and three-dimensional textural information. The BSE imaging was done on samples cut to provide cross-sectional views of the glass-filled shear band (or zone) that developed along the sawcut. Brightness in the BSE images increases with increasing mean atomic number of the material. Additional chemical information about the quenched melt and adjoining minerals was obtained using the energy dispersive system of the SEM during BSE examinations. However, the very narrow shear-band thicknesses and common occurrence of very fine lamellar compositional layering limited the usefulness of this technique for estimating melt chemistry.

  13. 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)

  14. Triaxial-band structures, chirality, and magnetic rotation in La133

    DOE PAGES

    Petrache, C. M.; Chen, Q. B.; Guo, S.; ...

    2016-12-05

    The structure of 133La has been investigated using the 116Cd(22Ne,4pn) reaction and the Gammasphere array. Three new bands of quadrupole transitions and one band of dipole transitions are identified and the previously reported level scheme is revised and extended to higher spins. The observed structures are discussed using the cranked Nilsson-Strutinsky formalism, covariant density functional theory, and the particle-rotor model. Triaxial configurations are assigned to all observed bands. For the high-spin bands it is found that rotations around different axes can occur, depending on the configuration. The orientation of the angular momenta of the core and of the activemore » particles is investigated, suggesting chiral rotation for two nearly degenerate dipole bands and magnetic rotation for one dipole band. As a result, it is shown that the h11/2 neutron holes present in the configuration of the nearly degenerate dipole bands have significant angular momentum components not only along the long axis but also along the short axis, contributing to the balance of the angular momentum components along the short and long axes and thus giving rise to a chiral geometry.« less

  15. Study on strength and deformation characteristics of sandy mudstone based on triaxial unloading test

    NASA Astrophysics Data System (ADS)

    Yuan, Xianfan

    2017-04-01

    To achieve the strength and deformation characteristics of sandy mudstone under the unloading condition, a triaxial unloading test was performed on a group of sandy mudstone taken from the diversion tunnel of a hydropower station. The results show that the stress-strain curve slope of sandy mudstone increases suddenly at the moment of unloading confining pressure, and there is no significant decline in the whole test. There is usually only a whole shear failure surface in the samples damaged under low initial unloading confining pressure while those damaged under high one develop tensile fracture. The introduction of semilog method helps to solve the problem that it’s difficult to get the peak intensity of sandy mudstone directly based on the variation characteristics of the stress-strain curve. From the initial stage of unloading to the damage of the samples, the reduced percentage of sandy mudstone deformation modulus is positively correlated with initial unloading confining pressure. The decrease rate of deformation modulus and increase rate of axial strain of sandy mudstone are both mutate under destructive confining pressure. The research results can provide an useful reference to research on the mechanical properties of similar soft rocks.

  16. Insights into Nuclear Triaxiality from Interference Effects in E2 Matrix Elements

    NASA Astrophysics Data System (ADS)

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

    2007-10-01

    Recently, we have introduced [1] a triaxial rotor model with independent inertia and E2 tensors. The E2 matrix elements [2] of the osmium isotopes (186, 188, 190, and 192) are studied in the framework of this model (59 of 84 E2 matrix elements deviate by 30% or less). It is shown that interference effects in the inertia tensor (K-mixing) and the E2 tensor can lead to significant reductions in the diagonal E2 matrix elements. In some instances, the diagonal E2 matrix elements may decrease with increasing spin. Additionally, a sum rule for diagonal E2 matrix elements is shown and used to explore missing strength from K-admixtures. [1] J.L. Wood, A-M. Oros-Peusquens, R. Zaballa, J.M. Allmond, and W.D. Kulp, Phys. Rev. C 70, 024308 (2004). [2] C.Y. Wu, D. Cline, T. Czosnyka, A. Backlin, C. Baktash, R.M. Diamond, G.D. Dracoulis, L. Hasselgren, H. Kluge, et al., Nucl. Phys. A607, 178 (1996).

  17. Triaxial search coil measurements of ELF waves in the plasmasphere: Initial results from EXOS-D

    SciTech Connect

    Kokubun, S.; Takami, M.; Hayashi, K. ); Kimura, I.; Sawada, A.; Kasahra, Y. ); Fukunishi, H.

    1991-02-01

    Triaxial search coil measurements of ELF waves in the frequency range below 50 Hz have been made with the polar orbiting satellite, EXOS-D (AKEBONO), in the plasmasphere. Single component electric field measurements were also obtained along with measurements of the magnetic field. A survey of realtime telemetry data received for the period of March - October, 1989 reveals the existence of variety of plasma waves in the frequency range around ion gyrofrequencies near the equatorial region of the plasmasphere. Electromagnetic noises with a multi-band structure were observed mostly above the local helium gyro-frequency (f{sub He{sup +}}), in the region of L values of 1.5{approximately}2.5. Multi-band ELF emission are common in the daytime and were observed in 49 out of 250 orbits examined here. Another type of electromagnetic ELF waves with a broad-band spectrum are also observed in the frequency range above the helium gyrofrequency in 10 orbits. Both types of wave spectra extend above the local proton gyrofrequency, but no absorption effect is observed at the local proton gyrofrequency. The electric field measurements clearly show spectral cut-off for both of these two types of waves near f {equals} (1.3{approximately}2.5) f{sub He{sup +}}. On the other hand, several spectral bands sometimes appear between the helium and oxygen gyrofrequencies in magnetic field components of multi-band emissions.

  18. Triaxial-band structures, chirality, and magnetic rotation in 133La

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

    The structure of 133La has been investigated using the (22Ne 116Cd,4 p n ) reaction and the Gammasphere array. Three new bands of quadrupole transitions and one band of dipole transitions are identified and the previously reported level scheme is revised and extended to higher spins. The observed structures are discussed using the cranked Nilsson-Strutinsky formalism, covariant density functional theory, and the particle-rotor model. Triaxial configurations are assigned to all observed bands. For the high-spin bands it is found that rotations around different axes can occur, depending on the configuration. The orientation of the angular momenta of the core and of the active particles is investigated, suggesting chiral rotation for two nearly degenerate dipole bands and magnetic rotation for one dipole band. It is shown that the h11 /2 neutron holes present in the configuration of the nearly degenerate dipole bands have significant angular momentum components not only along the long axis but also along the short axis, contributing to the balance of the angular momentum components along the short and long axes and thus giving rise to a chiral geometry.

  19. Internal triaxial strain imaging of visibly opaque black rubbers with terahertz polarization spectroscopy

    NASA Astrophysics Data System (ADS)

    Moriwaki, Atsuto; Okano, Makoto; Watanabe, Shinichi

    2017-10-01

    We demonstrate the nondestructive imaging of internal triaxial strain in visibly opaque black rubbers by employing the polarization-sensitive terahertz time-domain spectroscopy (PS THz-TDS) technique. From the sample thickness and the differences in amplitude and phase between orthogonal components of the terahertz wave that passed through the sample, the degree of birefringence and the angle of the slow optic axis were determined. We were able to convert the birefringence data into the amount and orientation of the internal strain through a Monte Carlo simulation that correlates the birefringent properties of the rubber with deformation. By comparing the strain map obtained from the PS THz-TDS measurements with that obtained by conventional digital image correlation, we found that both experimental and spatial distributions of the strain are in overall good agreement, except around the clamped sample regions. The deviations result from the intrinsic difference in the obtained strain information between two experiments and it is confirmed that our method based on PS THz-TDS is suited for evaluating the spatial distribution of the internal strain in black rubbers.

  20. 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.

  1. 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.

  2. A Missile-Borne Angular Velocity Sensor Based on Triaxial Electromagnetic Induction Coils.

    PubMed

    Li, Jian; Wu, Dan; Han, Yan

    2016-09-30

    Aiming to solve the problem of the limited measuring range for angular motion parameters of high-speed rotating projectiles in the field of guidance and control, a self-adaptive measurement method for angular motion parameters based on the electromagnetic induction principle is proposed. First, a framework with type bent "I-shape" is used to design triaxial coils in a mutually orthogonal way. Under the condition of high rotational speed of a projectile, the induction signal of the projectile moving across a geomagnetic field is acquired by using coils. Second, the frequency of the pulse signal is adjusted self-adaptively. Angular velocity and angular displacement are calculated in the form of periodic pulse counting and pulse accumulation, respectively. Finally, on the basis of that principle prototype of the sensor is researched and developed, performance of measuring angular motion parameters are tested on the sensor by semi-physical and physical simulation experiments, respectively. Experimental results demonstrate that the sensor has a wide measuring range of angular velocity from 1 rps to 100 rps with a measurement error of less than 0.3%, and the angular displacement measurement error is lower than 0.2°. The proposed method satisfies measurement requirements for high-speed rotating projectiles with an extremely high dynamic range of rotational speed and high precision, and has definite value to engineering applications in the fields of attitude determination and geomagnetic navigation.

  3. Experimental and Numerical Investigation of Permeability Evolution with Damage of Sandstone Under Triaxial Compression

    NASA Astrophysics Data System (ADS)

    Chen, Xu; Yu, Jin; Tang, Chun'an; Li, Hong; Wang, Shanyong

    2017-06-01

    A series of triaxial compression tests with permeability measurements was carried out under different confining pressure and pore pressure difference coupling conditions to investigate some mechanical properties and permeability evolution with damage of sandstone. It is found that the shapes of stress-strain curves, permeability evolution curves, and failure patterns are significantly affected by the confining pressure but are only slightly affected by the pore pressure difference. In addition, the corresponding numerical simulations of the experiments were then implemented based on the two-dimensional Realistic Failure Process Analysis-Flow (RFPA2D-Flow) code. In this simulator, the heterogeneity of rock is considered by assuming the material properties of the mesoscopic elements conform to a Weibull distribution and a statistical damage constitutive model based on elastic damage mechanics and the flow-stress-damage (FSD) coupling model. The numerical simulations reproduced the failure processes and failure patterns in detail, and the numerical results about permeability-strain qualitatively agree with the experimental results by assigning different parameters in the FSD model. Finally, the experimental results about relationship between permeability evolution and volumetric strain are discussed.

  4. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2010-11-01

    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↻ and j↻ 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 γ 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° (Rπ) i.e., RπT 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 163Lu.

  6. Simple solutions of fireball hydrodynamics for rotating and expanding triaxial ellipsoids and final state observables

    NASA Astrophysics Data System (ADS)

    Nagy, M. I.; Csörgő, T.

    2016-12-01

    We present a class of analytic solutions of nonrelativistic fireball hydrodynamics for a fairly general class of equation of state. The presented solution describes the expansion of a triaxial ellipsoid that rotates around one of its principal axes. We calculate the hadronic final state observables such as single-particle spectra, directed, elliptic, and third flows, as well as two-particle Bose-Einstein (also named HBT) correlations and corresponding radius parameters, utilizing simple analytic formulas. The final tilt angle of the fireball, an important observable quantity, is shown to be not independent of its exact definition: one gets different tilt angles from the geometrical anisotropies, from the single-particle spectra, and from HBT measurements. Taken together, the tilt angle in the momentum space and in the relative momentum or HBT variable may be sufficient for the determination of the magnitude of the rotation of the fireball. We argue that observing this rotation and its dependence on collision energy could characterize the softest point of the equation of state. Thus determining the rotation may be a powerful tool for the experimental search for the critical point in the phase diagram of strongly interacting matter.

  7. 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.

  8. Effect of quartz sand replacement by agate rejects in triaxial porcelain.

    PubMed

    Correia, Sivaldo L; Dienstmann, Gracieli; Folgueras, Marilena V; Segadaes, Ana M

    2009-04-15

    The ceramics industry, given the high volume of materials processed, stands as one of the largest consumers of natural raw materials but has also the capacity and potential to make significant contributions to solving environmental problems associated with other industries rejects. This work investigates the effects of quartz sand replacement by agate rejects (scrap) in a traditional triaxial porcelain composition. The study was carried out using the design of experiments (DoE) method. Characterization results were used to calculate statistically significant and valid regression equations, relating dried and fired body properties with clay, feldspar and agate scrap contents in the unfired mixture. The regression models were then discussed against X-ray diffraction and scanning electron microscopy results and used simultaneously to delimit the combinations of those three raw materials most adequate to produce a porcelainized stoneware floor tile with specified properties. Thus, an alternative use of an otherwise waste material is proposed, which can be translated into economic benefits and an important and welcome relief on environmental and waste disposal concerns.

  9. 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.

  10. Electrospun pH-sensitive core-shell polymer nanocomposites fabricated using a tri-axial process.

    PubMed

    Yang, Chen; Yu, Deng-Guang; Pan, Deng; Liu, Xin-Kuan; Wang, Xia; Bligh, S W Annie; Williams, Gareth R

    2016-04-15

    A modified tri-axial electrospinning process was developed for the generation of a new type of pH-sensitive polymer/lipid nanocomposite. The systems produced are able to promote both dissolution and permeation of a model poorly water-soluble drug. First, we show that it is possible to run a tri-axial process with only one of the three fluids being electrospinnable. Using an electrospinnable middle fluid of Eudragit S100 (ES100) with pure ethanol as the outer solvent and an unspinnable lecithin-diclofenac sodium (PL-DS) core solution, nanofibers with linear morphology and clear core/shell structures can be fabricated continuously and smoothly. X-ray diffraction proved that these nanofibers are structural nanocomposites with the drug present in an amorphous state. In vitro dissolution tests demonstrated that the formulations could preclude release in acidic conditions, and that the drug was released from the fibers in two successive steps at neutral pH. The first step is the dissolution of the shell ES100 and the conversion of the core PL-DS into sub-micron sized particles. This frees some DS into solution, and later the remaining DS is gradually released from the PL-DS particles through diffusion. Ex vivo permeation results showed that the composite nanofibers give a more than twofold uplift in the amount of DS passing through the colonic membrane as compared to pure DS; 74% of the transmitted drug was in the form of PL-DS particles. The new tri-axial electrospinning process developed in this work provides a platform to fabricate structural nanomaterials, and the core-shell polymer-PL nanocomposites we have produced have significant potential applications for oral colon-targeted drug delivery. A modified tri-axial electrospinning is demonstrated to create a new type of core-shell pH-sensitive polymer/lipid nanocomposites, in which an electrospinnable middle fluid is exploited to support the un-spinnable outer and inner fluids. The structural nanocomposites are able

  11. The dose dependent in vitro responses of MCF-7 and MDA-MB-231 cell lines to extracts of Vatica diospyroides symington type SS fruit include effects on mode of cell death

    PubMed Central

    Srisawat, Theera; Sukpondma, Yaowapa; Graidist, Potchanapond; Chimplee, Siriphon; Kanokwiroon, Kanyanatt

    2015-01-01

    Background: Vatica diospyroides type LS is a known source of valuable compounds for cancer treatment, however, in contrast little is known about therapeutic efficacy of type SS. Objective: This study focused on in vitro cytotoxicity of these fruit extracts, and the cell death mode they induce in breast cancer cells. Materials and Methods: Acetone extracts of fruit were tested for cytotoxicity against MCF-7 and MDA-MB-231 cell lines. The apoptosis and necrosis of these cells were quantified by fluorescence activated cell sorter (FACS) and western blot analyses. Results: After 72 h of treatment, the 50% growth inhibition concentrations (IC50) levels were 16.21 ± 0.13 µg/mL against MCF-7 and 30.0 ± 4.30 µg/mL against MDA-MB-231, indicating high and moderate cytotoxicity, respectively. From the FACS results, we estimate that the cotyledon extract at half IC50 produced 11.7% dead MCF-7 cells via apoptosis, whereas another concentrations both apoptosis and necrosis modes co-existed in a dose-dependent manner. In MDA-MB-231 cell line, only the apoptosis was induced by the pericarp extract in a dose-dependent manner. With the extracts at half IC50 concentration, in both cells, the expression of p21 decreased while that of Bax increased within 12–48 h of dosing, confirming apoptosis induced by time-dependent responses. Apoptosis dependent on p53 was found in MCF-7, whereas the mutant p53 of MDA-MB-231 cells was expressed. Conclusion: The results indicate that fruit extracts of V. diospyroides have cytotoxic effects against MCF-7 and MDA-MB-231 cells via apoptosis pathway in a dose-dependent manner. This suggests that the extracts could provide active ingredients for the development, targeting breast cancer therapy. PMID:26109760

  12. The t(11;14)(p15;q11) in a T-cell acute lymphoblastic leukemia cell line activates multiple transcripts, including Ttg-1, a gene encoding a potential zinc finger protein.

    PubMed Central

    McGuire, E A; Hockett, R D; Pollock, K M; Bartholdi, M F; O'Brien, S J; Korsmeyer, S J

    1989-01-01

    Interchromosomal translocations within lymphoid neoplasms frequently involve the antigen receptor genes. We cloned the breakpoints of the t(11;14)(p15;q11) in a CD3-negative T-cell acute lymphoblastic leukemia cell line (RPMI 8402) in order to identify new genes potentially involved in T-cell neoplasia. An extensive comparison of both breakpoints and their germ line counterparts indicated that an inadvertant recombinase-mediated break at chromosome segment 11p15 recombined with the delta T-cell receptor at 14q11. The derivative 11 breakpoint resembles a coding joint in which 11p15 rather than a variable region was introduced 5' to a D delta 1 D delta 2 J delta 1 intermediate rearrangement. Conversely, the derivative 14 breakpoint corresponds to a signal joint between the 5' heptamer-spacer-nonamer recombinational signal of D delta 1 and an isolated heptamer at 11p15. Multiple, apparently distinct transcripts were found flanking both breakpoints of 8402. RNAs of 3.5, 4.4, 1.4, and 8.0 kilobases originating from either side of the derivative 14 breakpoint were highly expressed in 8402 compared with other cells. This suggests that this translocation deregulated multiple genes and provides the opportunity to assess any multifactorial contribution they may have to malignancy. We cloned and sequenced several cDNAs representing the 1.4-kilobase transcript (termed Ttg-1 [T-cell translocation gene 1]) from an 8402 library. The predicted protein of 156 amino acids contained two internal repeats which could potentially form zinc fingers. Images PMID:2501659

  13. Comparison of a triaxial fluxgate magnetometer and Toftness sensometer for body surface EMF measurement

    PubMed Central

    Zhang, John; Toftness, Dave; Snyder, Brian; Nosco, Dennis; Balcavage, Walter; Nindl, Gabi

    2004-01-01

    Introduction The use of magnetic fields to treat disease has intrigued mankind since the time of the ancient Greeks. More recently it has been shown that electromagnetic field (EMF) treatment aids bone healing, and repetitive transcranial magnetic stimulation (rTMS) appears to be beneficial in treating schizophrenia and depression. Since external EMFs influence internal body processes, we hypothesized that measurement of body surface EMFs might be used to detect disease states and direct the course of subsequent therapy. However, measurement of minute body surface EMFs requires use of a sensitive and well documented magnetometer. In this study we evaluated the sensitivity and frequency response of a fluxgate magnetometer with a triaxial probe for use in detecting body surface EMF and we compared the magnetometer readings with a signal from a Toftness Sensometer, operated by an experienced clinician, in the laboratory and in a clinical setting. Methods A Peavy Audio Amplifier and variable power output Telulex signal generator were used to develop 50 μT EMFs in a three coil Merritt coil system. A calibrated magnetometer was used to set a 60 Hz 50 μT field in the coil and an ammeter was used to measure the current required to develop the 50 μT field. At frequencies other than 60 Hz, the field strength was maintained at 50 μT by adjusting the Telulex signal output to keep the current constant. The field generated was monitored using a 10 turn coil connected to an oscilloscope. The oscilloscope reading indicated that the field strength was the same at all frequencies tested. To determine if there was a correspondence between the signals detected by a fluxgate magnetometer (FGM1) and the Toftness Sensometer both devices were placed in the Merritt coil and readings were recorded from the FGM1 and compared with the ability of a highly experienced Toftness operator to detect the 50 μT field. Subsequently, in a clinical setting, FGM1 readings made by an FGM1 technician

  14. Comparison of a triaxial fluxgate magnetometer and Toftness sensometer for body surface EMF measurement.

    PubMed

    Zhang, John; Toftness, Dave; Snyder, Brian; Nosco, Dennis; Balcavage, Walter; Nindl, Gabi

    2004-12-01

    The use of magnetic fields to treat disease has intrigued mankind since the time of the ancient Greeks. More recently it has been shown that electromagnetic field (EMF) treatment aids bone healing, and repetitive transcranial magnetic stimulation (rTMS) appears to be beneficial in treating schizophrenia and depression. Since external EMFs influence internal body processes, we hypothesized that measurement of body surface EMFs might be used to detect disease states and direct the course of subsequent therapy. However, measurement of minute body surface EMFs requires use of a sensitive and well documented magnetometer. In this study we evaluated the sensitivity and frequency response of a fluxgate magnetometer with a triaxial probe for use in detecting body surface EMF and we compared the magnetometer readings with a signal from a Toftness Sensometer, operated by an experienced clinician, in the laboratory and in a clinical setting. A Peavy Audio Amplifier and variable power output Telulex signal generator were used to develop 50 microT EMFs in a three coil Merritt coil system. A calibrated magnetometer was used to set a 60 Hz 50 microT field in the coil and an ammeter was used to measure the current required to develop the 50 microT field. At frequencies other than 60 Hz, the field strength was maintained at 50 microT by adjusting the Telulex signal output to keep the current constant. The field generated was monitored using a 10 turn coil connected to an oscilloscope. The oscilloscope reading indicated that the field strength was the same at all frequencies tested. To determine if there was a correspondence between the signals detected by a fluxgate magnetometer (FGM1) and the Toftness Sensometer both devices were placed in the Merritt coil and readings were recorded from the FGM1 and compared with the ability of a highly experienced Toftness operator to detect the 50 microT field. Subsequently, in a clinical setting, FGM1 readings made by an FGM1 technician and

  15. Hydraulic properties of siliciclastic geothermal reservoir rocks under triaxial stress conditions, a multidisciplinary approach.

    NASA Astrophysics Data System (ADS)

    Bakker, Richard; Gholizadeh Doonechaly, Nima; Bruhn, David

    2017-04-01

    Cretaceous Sandstone bodies in the subsurface of western Netherlands are already used for heating some of the greenhouses in that area. The reservoirs used are typically at depths between 1500 and 3000m, with temperatures generally <100 ˚C. For higher temperature applications deeper reservoirs are required. However, deeper reservoirs are subjected to higher effective pressures due to more overburden, which can lead to more compacted rocks, and thereby reduced permeability. We assess the effects of effective pressure on Triassic Buntsandstein, a formation targeted to act as a deep geothermal reservoir in the western Netherlands. Rock samples are acquired from laterally equivalent quarries and prepared for permeability measurements within a tri-axial apparatus. To determine anisotropy, cores are drilled both perpendicular and parallel to bedding. Experiments are conducted by maintaining hydrostatic confining pressure, stepwise increasing up to 700 bar (if still permeable enough for accurate measurements) and a pore pressure of 25 bar. At each step the permeability is assessed by imposing a number of constant flow rates and continuous measurement of the pore pressure difference between up and downstream reservoirs. Throughout the experiment the sample strain is measured in radial and axial directions, such that elastic constants can be determined and micromechanical mechanisms may be observed. In addition to measurements on in-tact rock samples, we also assess the effect of induced fracturing on permeability by similar measurements. First, rock samples are fractured within the tri-axial cell with normal jacketing to evaluate the stress conditions of failure. Secondly, the experiment is repeated using relatively strong jackets which remain sealing after sample failure, allowing for permeability measurements. Preliminary results show that an increase of confining pressure leads to a decrease of permeability by three orders of magnitude, from 1e-13 to 1e-16 m2

  16. The Language of Lines.

    ERIC Educational Resources Information Center

    Breig-Allen, Cheryl; Hill, Janet; Geismar-Ryan, Lori; Cadwell, Louise Boyd

    1998-01-01

    Describes a project about lines in the environment used with 2- and 3-year olds and based on the Reggio Emilia approach. Activities included making tracks with riding toys, drawing lines on papers, seeing cloud lines, and making lines with yarn and Cuisenaire rods. Shows how young children's observations and ongoing discoveries can uncover their…

  17. The Language of Lines.

    ERIC Educational Resources Information Center

    Breig-Allen, Cheryl; Hill, Janet; Geismar-Ryan, Lori; Cadwell, Louise Boyd

    1998-01-01

    Describes a project about lines in the environment used with 2- and 3-year olds and based on the Reggio Emilia approach. Activities included making tracks with riding toys, drawing lines on papers, seeing cloud lines, and making lines with yarn and Cuisenaire rods. Shows how young children's observations and ongoing discoveries can uncover their…

  18. 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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. 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.

  20. Concurrent validity of a trunk tri-axial accelerometer system for gait analysis in older adults.

    PubMed

    Hartmann, Antonia; Luzi, Susanna; Murer, Kurt; de Bie, Rob A; de Bruin, Eling D

    2009-04-01

    The aim of this study was (1) to determine the concurrent validity of a trunk tri-axial accelerometer system (DynaPort) with the GAITRite system for spatio-temporal gait parameters at preferred, slow and fast self-selected walking speed that were recorded for averaged and individual step data in an older adult population and (2) to compare the levels of agreement for averaged step data from different walking distances and individual step data. The levels of agreement between the two systems for averaged step data was excellent for walking speed, cadence, step duration and step length (intraclass correlation coefficients (ICCs) between 0.99 and 1.00, ratios limits of agreement (RLOA) between 0.7% and 3.3%), moderate for variability of step duration (ICCs between 0.88 and 0.98 and RLOAs between 19% and 34%) and low for variability of step length (ICCs between 0.24 and 0.33 and RLOAs between 73% and 87%). The levels of agreement for individual step duration and step length were moderate with ICCs between 0.81 and 0.89 and with RLOAs between 9% and 13%. Comparing RLOAs from averaged step data across the different walking distances and individual step data, the RLOAs decreased with increased number of steps. The results of this study demonstrate that the DynaPort system, which allows measurements in real life conditions, is a highly valid tool for assessment of spatio-temporal gait parameters for averaged step data across a walkway length of approximately 20m in independent living elderly. Gait variability measures and individual step data need to be viewed with caution because of the moderate to low levels of agreement between the two systems.

  1. 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.

  2. Comparing the 7-Day PAR with a Triaxial Accelerometer for Measuring Time in Exercise

    PubMed Central

    Sloane, Richard; Snyder, Denise Clutter; Demark-Wahnefried, Wendy; Lobach, David; Kraus, William E.

    2009-01-01

    Purpose The primary study aim was to evaluate associations of estimated weekly minutes of moderate-to-vigorous intensity exercise from self-reports of the telephone-administered 7-Day Physical Activity Recall (PAR) with data captured by the RT3 triaxial accelerometer. Methods This investigation was undertaken as part of the FRESH START study, a randomized clinical trial that tested an iteratively-tailored diet and exercise mailed print intervention among newly diagnosed breast and prostate cancer survivors. A convenience sample of 139 medically-eligible subjects living within a 60-mile radius of the study center provided both 7-Day PAR and accelerometer data at enrollment. Ultimately n=115 substudy subjects were found eligible for the FRESH START study and randomized to one of two study treatment arms. Follow-up assessments at Year 1 (n=103) and Year 2 (n=99) provided both the 7-Day PAR and accelerometer data. Results There was moderate agreement between the 7-Day PAR and the accelerometer with longitudinal serial correlation coefficients of .54 (baseline), .24 (Year 1) and .53 (Year 2), all P-values < .01, though the accelerometer estimates for weekly time in moderate-to-vigorous physical activity were much higher than those of the 7-Day PAR at all time points. The two methods were poorly correlated in assessing sensitivity to change from baseline to Year 1 (rho=.11, P=.30). Using mixed models repeated measures analysis, both methods exhibited similar non-significant treatment arm X time interaction P-values (7-Day PAR=.22, accelerometer=.23). Conclusions The correlations for three serial time points were in agreement with findings of other studies that compared self-reported time in exercise with physical activity captured by accelerometry. However, these methods capture somewhat different dimensions of physical activity and provide differing estimates of change over time. PMID:19461530

  3. Failure characteristics of two porous sandstones subjected to true triaxial stresses

    NASA Astrophysics Data System (ADS)

    Ma, Xiaodong; Haimson, Bezalel C.

    2016-09-01

    We conducted an extensive suite of true triaxial experiments in two porous sandstones, Bentheim (porosity ≈ 24%) and Coconino (17.5%). Our experiments demonstrate that failure of both sandstones is not only a function of σ3 but also of σ2. For a given σ3, σ1 at failure (σ1,peak) increases as σ2 is raised above σ3 between tests. The σ1,peak reaches a peak as σ2 is about halfway between σ3 and σ1 and then gradually decreases such that when σ2 ≈ σ1,peak, it approaches its initial magnitude when σ2 = σ3. For a constant σ3, failure-plane angle increases with σ2 by a maximum of less than 10° as σ2 rises from σ2 = σ3 to σ2 = σ1,peak. The effect of σ2 on both failure level and failure-plane angle is stronger in the lower-porosity Coconino sandstone than in the Bentheim sandstone. The σ2 dependence of failure mode in the Bentheim is different than Coconino over the same σ3 range. Both sandstones failed dilatantly at low σ3 magnitudes. However, at high σ3 (100-120 MPa), Bentheim sandstone developed shear-enhanced compaction bands, followed by pure compaction bands at σ3 = 150 MPa. Compaction bands were not observed in the Coconino. Microscopic observations via SEM reveal that tensile microcracking is dominant when shear banding occurs (under low σ3), while pervasive grain crushing and pore collapse inside compaction bands are observed at high σ3.

  4. Frictional behaviour of sandstone: A sample-size dependent triaxial investigation

    NASA Astrophysics Data System (ADS)

    Roshan, Hamid; Masoumi, Hossein; Regenauer-Lieb, Klaus

    2017-01-01

    Frictional behaviour of rocks from the initial stage of loading to final shear displacement along the formed shear plane has been widely investigated in the past. However the effect of sample size on such frictional behaviour has not attracted much attention. This is mainly related to the limitations in rock testing facilities as well as the complex mechanisms involved in sample-size dependent frictional behaviour of rocks. In this study, a suite of advanced triaxial experiments was performed on Gosford sandstone samples at different sizes and confining pressures. The post-peak response of the rock along the formed shear plane has been captured for the analysis with particular interest in sample-size dependency. Several important phenomena have been observed from the results of this study: a) the rate of transition from brittleness to ductility in rock is sample-size dependent where the relatively smaller samples showed faster transition toward ductility at any confining pressure; b) the sample size influences the angle of formed shear band and c) the friction coefficient of the formed shear plane is sample-size dependent where the relatively smaller sample exhibits lower friction coefficient compared to larger samples. We interpret our results in terms of a thermodynamics approach in which the frictional properties for finite deformation are viewed as encompassing a multitude of ephemeral slipping surfaces prior to the formation of the through going fracture. The final fracture itself is seen as a result of the self-organisation of a sufficiently large ensemble of micro-slip surfaces and therefore consistent in terms of the theory of thermodynamics. This assumption vindicates the use of classical rock mechanics experiments to constrain failure of pressure sensitive rocks and the future imaging of these micro-slips opens an exciting path for research in rock failure mechanisms.

  5. Evidence for octupole vibration in the triaxial superdeformed well of {sup 164}Lu.

    SciTech Connect

    Bringel, P.; Engelhardt, C.; Hubel, H.; NeuBer-Neffgen, A.; Odegard, S. W.; Hagemann, G. B.; Hansen, C. R.; Herskind, B.; Sletten, G.; Carpenter, M. P.; Janssens, R. V. F.; Khoo, T. L.; Lauritsen, T.; Seweryniak, D.; Ma, W. C.; Roux, D. G.; Chowdhury, P.; Physics; Univ. Bonn; Univ. of Oslo; Niels Bohr Inst.; Mississippi State Univ.; Univ. of Massachusetts

    2007-01-01

    High-spin states in {sup 164}Lu were populated in the {sup 121}Sb({sup 48}Ca,5n) reaction at 215 MeV and {gamma}-ray coincidences were measured with the Gammasphere spectrometer. Through this experiment the eight known triaxial superdeformed bands in {sup 164}Lu could be confirmed. Some of these bands were extended to higher as well as to lower spins. Evidence is reported for the first time for weak {delta}I=1,E1 transitions linking TSD3 and TSD1. This observation may imply coupling to octupole vibrational degrees of freedom. The decay mechanism is different from the one observed in the neighboring even-N isotopes, which exhibit wobbling excitations built on the {pi}i{sub 13/2} structure with E2(M1),{delta}I=1 interband decay. An additional sequence decaying at high spin into TSD1 was observed up to I{sup {pi}}=(50{sup -}). This band has a constant dynamic moment of inertia of {approx}70({Dirac_h}/2{pi}){sup 2}MeV{sup -1} and an alignment that is {approx}2({Dirac_h}/2{pi}) larger than that found for TSD1. A revision of the assumed spin-parity-assignment of TSD2 is based on the observed decay-out to normal-deformed structures. The parity and signature quantum numbers of TSD2 are now firmly assigned as ({pi},{alpha})=(+,0), in disagreement with the former assignment of ({pi},{alpha})=(-,1), which was based on the assumption that TSD2 is the signature partner of TSD1. TSD1 and TSD2 show an alignment gain at ({Dirac_h}/2{pi}){omega}{approx}0.67 and 0.60 MeV, respectively. In TSD1 the involvement of the j{sub 15/2} neutron orbital is suggested to be responsible for the high-frequency crossing.

  6. Evidence for octupole vibration in the triaxial superdeformed well of {sup 164}Lu

    SciTech Connect

    Bringel, P.; Engelhardt, C.; Huebel, H.; Neusser-Neffgen, A.; Odega ring rd, S. W.; Hagemann, G. B.; Hansen, C. R.; Herskind, B.; Sletten, G.; Carpenter, M. P.; Janssens, R. V. F.; Khoo, T. L.; Lauritsen, T.; Seweryniak, D.; Ma, W. C.; Roux, D. G.; Chowdhury, P.

    2007-04-15

    High-spin states in {sup 164}Lu were populated in the {sup 121}Sb({sup 48}Ca,5n) reaction at 215 MeV and {gamma}-ray coincidences were measured with the Gammasphere spectrometer. Through this experiment the eight known triaxial superdeformed bands in {sup 164}Lu could be confirmed. Some of these bands were extended to higher as well as to lower spins. Evidence is reported for the first time for weak {delta}I=1,E1 transitions linking TSD3 and TSD1. This observation may imply coupling to octupole vibrational degrees of freedom. The decay mechanism is different from the one observed in the neighboring even-N isotopes, which exhibit wobbling excitations built on the {pi}i{sub 13/2} structure with E2(M1),{delta}I=1 interband decay. An additional sequence decaying at high spin into TSD1 was observed up to I{sup {pi}}=(50{sup -}). This band has a constant dynamic moment of inertia of {approx}70({Dirac_h}/2{pi}){sup 2}MeV{sup -1} and an alignment that is {approx}2({Dirac_h}/2{pi}) larger than that found for TSD1. A revision of the assumed spin-parity-assignment of TSD2 is based on the observed decay-out to normal-deformed structures. The parity and signature quantum numbers of TSD2 are now firmly assigned as ({pi},{alpha})=(+,0), in disagreement with the former assignment of ({pi},{alpha})=(-,1), which was based on the assumption that TSD2 is the signature partner of TSD1. TSD1 and TSD2 show an alignment gain at ({Dirac_h}/2{pi}){omega}{approx}0.67 and 0.60 MeV, respectively. In TSD1 the involvement of the j{sub 15/2} neutron orbital is suggested to be responsible for the high-frequency crossing.

  7. Physical activity levels in three Brazilian birth cohorts as assessed with raw triaxial wrist accelerometry.

    PubMed

    da Silva, Inácio Cm; van Hees, Vincent T; Ramires, Virgílio V; Knuth, Alan G; Bielemann, Renata M; Ekelund, Ulf; Brage, Soren; Hallal, Pedro C

    2014-12-01

    Data on objectively measured physical activity are lacking in low- and middle-income countries. The aim of this study was to describe objectively measured overall physical activity and time spent in moderate-to-vigorous physical activity (MVPA) in individuals from the Pelotas (Brazil) birth cohorts, according to weight status, socioeconomic status (SES) and sex. All children born in 1982, 1993 and 2004 in hospitals in the city of Pelotas, Brazil, constitute the sampling frame; of these 99% agreed to participate. The most recent follow-ups were conducted between 2010 and 2013. In total, 8974 individuals provided valid data derived from raw triaxial wrist accelerometry. The average acceleration is presented in milli-g (1 mg = 0.001g), and time (min/d) spent in MVPA (>100 mg) is presented in 5- and 10-min bouts. Mean acceleration in the 1982 (mean age 30.2 years), 1993 (mean age 18.4 years) and 2004 (mean age 6.7 years) cohorts was 35 mg, 39 mg and 60 mg, respectively. Time spent in MVPA was 26 [95% confidence interval (CI) 25; 27], 43 (95% CI 42; 44) and 45 (95% CI 43; 46) min/d in the three cohorts, respectively, using 10-min bouts. Mean MVPA was on average 42% higher when using 5-min bouts. Males were more active than females and physical activity was inversely associated with age of the cohort and SES. Normal-weight individuals were more active than underweight, overweight and obese participants. Overall physical activity and time spent in MVPA differed by cohort (age), sex, weight status and SES. Higher levels of activity in low SES groups may be explained by incidental physical activity. © The Author 2014. Published by Oxford University Press on behalf of the International Epidemiological Association.

  8. Physical activity levels in three Brazilian birth cohorts as assessed with raw triaxial wrist accelerometry

    PubMed Central

    da Silva, Inácio CM; van Hees, Vincent T; Ramires, Virgílio V; Knuth, Alan G; Bielemann, Renata M; Ekelund, Ulf; Brage, Soren; Hallal, Pedro C

    2014-01-01

    Background: Data on objectively measured physical activity are lacking in low- and middle-income countries. The aim of this study was to describe objectively measured overall physical activity and time spent in moderate-to-vigorous physical activity (MVPA) in individuals from the Pelotas (Brazil) birth cohorts, according to weight status, socioeconomic status (SES) and sex. Methods: All children born in 1982, 1993 and 2004 in hospitals in the city of Pelotas, Brazil, constitute the sampling frame; of these 99% agreed to participate. The most recent follow-ups were conducted between 2010 and 2013. In total, 8974 individuals provided valid data derived from raw triaxial wrist accelerometry. The average acceleration is presented in milli-g (1 mg = 0.001g), and time (min/d) spent in MVPA (>100 mg) is presented in 5- and 10-min bouts. Results: Mean acceleration in the 1982 (mean age 30.2 years), 1993 (mean age 18.4 years) and 2004 (mean age 6.7 years) cohorts was 35 mg, 39 mg and 60 mg, respectively. Time spent in MVPA was 26 [95% confidence interval (CI) 25; 27], 43 (95% CI 42; 44) and 45 (95% CI 43; 46) min/d in the three cohorts, respectively, using 10-min bouts. Mean MVPA was on average 42% higher when using 5-min bouts. Males were more active than females and physical activity was inversely associated with age of the cohort and SES. Normal-weight individuals were more active than underweight, overweight and obese participants. Conclusions: Overall physical activity and time spent in MVPA differed by cohort (age), sex, weight status and SES. Higher levels of activity in low SES groups may be explained by incidental physical activity. PMID:25361583

  9. 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.

  10. 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.

  11. A combination of gefitinib and FOLFOX-4 as first-line treatment in advanced colorectal cancer patients. A GISCAD multicentre phase II study including a biological analysis of EGFR overexpression, amplification and NF-kB activation

    PubMed Central

    Cascinu, S; Berardi, R; Salvagni, S; Beretta, G D; Catalano, V; Pucci, F; Sobrero, A; Tagliaferri, P; Labianca, R; Scartozzi, M; Crocicchio, F; Mari, E; Ardizzoni, A

    2007-01-01

    Interesting activity has been reported by combining chemotherapy with cetuximab. An alternative approach for blocking EGFR function has been the development of small-molecule inhibitors of tyrosine kinase domain such as gefitinib. We designed a multicentre phase II study in advanced colorectal cancer combining gefitinib+FOLFOX in order to determine the activity and to relate EGFR expression and gene amplification and NF-kB activation to therapeutic results. Patients received FOLFOX-4 regimen plus gefitinib as first-line treatment. Tumour samples were analysed for EGFR protein expression by immunohistochemical analysis and for EGFR gene amplification by fluorescence in situ hybridisation (FISH), chromogenic in situ hybridisation (CISH) and NF-kB activation. Forty-three patients were enrolled into this study; 15 patients experienced a partial response (response rate=34.9%), whereas other 12 (27.9%) had a stable disease. Median progression-free survival (PFS) was 7.8 months and median overall survival (OS) was 13.9 months. We did not find any relationship with EGFR overexpression, gene amplification, while NF-kB activation was associated with a resistance to therapy. Gefitinib does not seem to increase the activity of FOLFOX in advanced colorectal cancer even in patients overexpressing EGFR or with EGFR amplification. Furthermore, while NF-kB activation seems to predict resistance to chemotherapy as demonstrated ‘in vitro' models, gefitinib does not overcome this mechanism of resistance, as reported for cetuximab. PMID:18059397

  12. 34 CFR 303.15 - Include; including.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 2 2010-07-01 2010-07-01 false Include; including. 303.15 Section 303.15 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION EARLY INTERVENTION PROGRAM FOR INFANTS AND TODDLERS WITH...

  13. 34 CFR 303.15 - Include; including.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 34 Education 2 2011-07-01 2010-07-01 true Include; including. 303.15 Section 303.15 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION EARLY INTERVENTION PROGRAM FOR INFANTS AND TODDLERS WITH...

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

    PubMed

    Schütte, Kurt H; Maas, Ellen A; Exadaktylos, Vasileios; Berckmans, Daniel; Venter, Rachel E; Vanwanseele, Benedicte

    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.

  15. Micro-seismicity and permeability enhancement in sandstone and andesite ruptured by fluid injection under triaxial conditions

    NASA Astrophysics Data System (ADS)

    Nicolas, Aurélien; Blöcher, Guido; Li, Zhi; Kluge, Christian; Pei, Liang; Hofmann, Hannes; Milsch, Harald; Guéguen, Yves

    2017-04-01

    Hydraulic stimulation of a well alters the physical properties (such as permeability) of the surrounding rock and potentially triggers seismicity. This is of special interest for exploitation of geothermal fields for which permeability needs to be enhanced, but induced seismicity should be avoided. Therefore, we performed a study combining records of acoustic emissions (equivalent to micro-seismicity) and local permeability evolution in two permeable rocks: Flechtinger sandstone (Bebertal, Germany) and an andesite from Guadeloupe (French Antillas). In this study, mechanical instability is triggered in the laboratory by injecting fluid in the pores of the rock (increasing pore pressure) in samples that are under triaxial stresses. During the experiments, acoustic emissions and local permeability changes are recorded with a passive acoustic system and fiber optic measurements, respectively. Samples are hydrostatically loaded to 20 MPa and then axially loaded to a differential stress of 100 MPa. This stress state is maintained constant for 24h to make sure that no brittle creep takes place and could lead to the macroscopic failure. Then, a pore pressure of 15 MPa is applied at the bottom of the sample and maintained constant. These experiments were performed in the triaxial cell installed at ENS Paris, which is instrumented with 16 acoustic sensors to record acoustic emissions. During pore pressure increase, acoustic emissions are recorded to understand the coupling between water front migration and induced seismicity. However, local permeability changes could not be recorded with this setup. Thus, the same experiments are performed in a similar triaxial cell at GFZ Potsdam where the samples are instrumented with three optic fibers that are able to record local pore pressure at three equidistant locations along the sample axis. Permeability evolution along the sample axis is calculated with Darcy's law between the points of local pore pressure measurements. By

  16. 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

  17. Modelling the stress-strain behaviour of saturated rocks undergoing triaxial deformation using complex electrical conductivity measurements

    NASA Astrophysics Data System (ADS)

    Glover, P. W. J.; Gomez, J. B.; Meredith, P. G.; Boon, S. A.; Sammonds, P. R.; Murrell, S. A. F.

    1996-05-01

    Measurement of complex electrical conductivity as a function of frequency is an extremely sensitive probe for changes in pore and crack volume, crack connectivity, and crack surface topography. Such measurements have been made as a function of pore fluid chemistry, hydrostatic confining pressure, as well as uniaxial and triaxial deformation. This paper will; (1) describe the effects of triaxial deformation on the complex electrical conductivity of saturated porous rocks, (2) use the electrical data to model the mechanical stress-strain behaviour, and (3) compare the modelled behaviour with the stress-strain behaviour measured during the deformation. Experimental conductivity data tracks how the rock undergoes compaction with progressive loss of crack volume, followed by dilatation due to new crack formation, growth of existing cracks, crack interlinkage, and finally failure, as axial strain is increased. We have used the complex electrical data to produce a direction-sensitive (anisotropic) crack damage parameter, and used it to calculate the effective Young's modulus by employing the models of Walsh and Bruner. Comparison of the synthetic stress-strain curves so produced, with the experimentally derived stress-strain curves shows good agreement, particularly for undrained tests. This modelling is an improvement on similar curves produced using isotropic crack damage parameters derived from acoustic emission data. The improvement is likely to be due to the directional sensitivity of the electrical conductivity measurement, and its ability to discriminate between the formation of isolated cracks, and those cracks that contribute to the inter-connected crack space i.e. those cracks upon which transport properties of the rock such as electrical conductivity, and mechanical properties depend most critically during triaxial deformation.

  18. 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.

  19. Location and stability of L1 for the elliptic restricted three-body problem with oblate and triaxial primaries

    NASA Astrophysics Data System (ADS)

    Masoud, Akram; Rahoma, Walid Ali; Abd El-Salam, Fawzy

    2016-07-01

    My subject of study is the point L1 with oblate and triaxial primaries in the elliptic restricted three-body problem (ERTBP). The study contains a mathematical determination of the location of this point in the form of a power series in the mass ratio and a discussion of its stability. The difference between the location of L1 in the perturbed ERTBP and in the classical circular restricted three-body problem (CRTBP) is graphically represented versus the mass ratio. To study the effect of a small displacement, a test particle is assumed to be subjected in the location of L1.

  20. 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.

  1. Deformation of rotational structures in {sup 73}Kr and {sup 74}Rb: Probing the additivity principle at triaxial shapes

    SciTech Connect

    Johnston-Theasby, F.; Jenkins, D. G.; Joshi, P.; Wadsworth, R.; Afanasjev, A. V.; Andreoiu, C.; Svensson, C. E.; Austin, R. A. E.; Carpenter, M. P.; Greene, J.; Moore, F.; Mukherjee, G.; Seweryniak, D.; Dashdorj, D.; Freeman, S. J.; Garrett, P. E.; Goergen, A.; Reviol, W.

    2008-09-15

    Lifetimes have been deduced in the intermediate/high-spin range for the three known rotational bands in {sup 73}Kr and the T=0 band in {sup 74}Rb using the residual Doppler shift method. This has enabled relative transition quadrupole moments to be studied for the first time in triaxial nuclei as a function of spin. The data suggest that the additivity principle for transition quadrupole moments is violated, a result that is in disagreement with predictions from cranked Nilsson-Strutinsky and cranked relativistic mean-field theory calculations. The reasons for the discrepancy are not understood but may indicate that important correlations are missing from the models.

  2. Poisson equations of rotational motion for a rigid triaxial body with application to a tumbling artificial satellite

    NASA Technical Reports Server (NTRS)

    Liu, J. J. F.; Fitzpatrick, P. M.

    1975-01-01

    A mathematical model is developed for studying the effects of gravity gradient torque on the attitude stability of a tumbling triaxial rigid satellite. Poisson equations are used to investigate the rotation of the satellite (which is in elliptical orbit about an attracting point mass) about its center of mass. An averaging method is employed to obtain an intermediate set of differential equations for the nonresonant, secular behavior of the osculating elements which describe the rotational motions of the satellite, and the averaged equations are then integrated to obtain long-term secular solutions for the osculating elements.

  3. 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.

  4. Quasi-Static Compression and Low-Velocity Impact Behavior of Tri-Axial Bio-Composite Structural Panels Using a Spherical Head.

    PubMed

    Li, Jinghao; Hunt, John F; Gong, Shaoqin; Cai, Zhiyong

    2017-02-15

    This paper presents experimental results of both quasi-static compression and low-velocity impact behavior for tri-axial bio-composite structural panels using a spherical load head. Panels were made having different core and face configurations. The results showed that panels made having either carbon fiber fabric composite faces or a foam-filled core had significantly improved impact and compressive performance over panels without either. Different localized impact responses were observed based on the location of the compression or impact relative to the tri-axial structural core; the core with a smaller structural element had better impact performance. Furthermore, during the early contact phase for both quasi-static compression and low-velocity impact tests, the panels with the same configuration had similar load-displacement responses. The experimental results show basic compression data could be used for the future design and optimization of tri-axial bio-composite structural panels for potential impact applications.

  5. 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

  6. 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 grain

  7. Triaxial testing of Lopez Fault gouge at 150 MPa mean effective stress

    USGS Publications Warehouse

    Scott, D.R.; Lockner, D.A.; Byerlee, J.D.; Sammis, C.G.

    1994-01-01

    Triaxial compression experiments were performed on samples of natural granular fault gouge from the Lopez Fault in Southern California. This material consists primarily of quartz and has a self-similar grain size distribution thought to result from natural cataclasis. The experiments were performed at a constant mean effective stress of 150 MPa, to expose the volumetric strains associated with shear failure. The failure strength is parameterized by the coefficient of internal friction ??, based on the Mohr-Coulomb failure criterion. Samples of remoulded Lopez gouge have internal friction ??=0.6??0.02. In experiments where the ends of the sample are constrained to remain axially aligned, suppressing strain localisation, the sample compacts before failure and dilates persistently after failure. In experiments where one end of the sample is free to move laterally, the strain localises to a single oblique fault at around the point of failure; some dilation occurs but does not persist. A comparison of these experiments suggests that dilation is confined to the region of shear localisation in a sample. Overconsolidated samples have slightly larger failure strengths than normally consolidated samples, and smaller axial strains are required to cause failure. A large amount of dilation occurs after failure in heavily overconsolidated samples, suggesting that dilation is occurring throughout the sample. Undisturbed samples of Lopez gouge, cored from the outcrop, have internal friction in the range ??=0.4-0.6; the upper end of this range corresponds to the value established for remoulded Lopez gouge. Some kind of natural heterogeneity within the undisturbed samples is probably responsible for their low, variable strength. In samples of simulated gouge, with a more uniform grain size, active cataclasis during axial loading leads to large amounts of compaction. Larger axial strains are required to cause failure in simulated gouge, but the failure strength is similar to that of

  8. Effect of shallow angles on compressive strength of biaxial and triaxial laminates.

    PubMed

    Jia, Hongli; Yang, Hyun-Ik

    2016-01-01

    Biaxial (BX) and triaxial (TX) composite laminates with ±45° angled plies have been widely used in wind turbine blades. As the scale of blades increases, BX and TX laminates with shallow-angled plies (i.e. off-axis ply angle <45°) might be utilized for reducing mass and/or improving performance. The compressive properties of shallow-angled BX and TX laminates are critical considering their locations in a wind turbine blade, and therefore in this study, the uniaxial static compression tests were conducted using BX and TX laminates with angled-plies of ±45°, ±35°, and ±25°, for the purpose of evaluation. On the other hand, Mori-Tanaka mean field homogenization method was employed to predict elastic constants of plies in BX and TX laminates involved in tests; linear regression analyses of experimentally measured ply strengths collected from various sources were then performed to estimate strengths of plies in BX and TX laminates; finally, Tsai-Wu, Hashin, and Puck failure criteria were chosen to predict compressive strengths of BX and TX laminates. Comparison between theoretical predictions and test results were carried out to illustrate the effectiveness of each criterion. The compressive strength of BX laminate decreases as ply angle increases, and the trend was successfully predicted by all three failure criteria. For TX laminates, ±35° angled plies rather than ±45° angled plies led to the lowest laminate compressive strength. Hashin and Puck criteria gave good predictions at certain ply angles for TX laminates, but Tsai-Wu criterion was able to capture the unexpected strength variation of TX laminates with ply angle. It was concluded that the transverse tensile stress in 0° plies of TX laminates, which attains its maximum when the off-axis ply angle is 35°, is the dominant factor in failure determination if using Tsai-Wu criterion. This explains the unexpected strength variation of TX laminates with ply angle, and also indicates that proper

  9. Design and evaluation of a novel triaxial isometric trunk muscle strength measurement system.

    PubMed

    Azghani, M R; Farahmand, F; Meghdari, A; Vossoughi, G; Parnianpour, M

    2009-08-01

    Maximal strength measurements of the trunk have been used to evaluate the maximum functional capacity of muscles and the potential mechanical overload or overuse of the lumbar spine tissues in order to estimate the risk of developing musculoskeletal injuries. A new triaxial isometric trunk strength measurement system was designed and developed in the present study, and its reliability and performance was investigated. The system consisted of three main revolute joints, equipped with torque sensors, which intersect at L5-S1 and adjustment facilities to fit the body anthropometry and to accommodate both symmetric and asymmetric postures in both seated and standing positions. The dynamics of the system was formulated to resolve validly the moment generated by trunk muscles in the three anatomic planes. The optimal gain and offset of the system were obtained using deadweights based on the least-squares linear regression analysis. The R2 results of calibration for all loading courses of all joints were higher than 0.99, which indicated an excellent linear correlation. The results of the validation analysis of the regression model suggested that the mean absolute error and the r.m.s. error were less than 2 per cent of the applied load. The maximum value of the minimum detectable change was found to be 1.63 Nm for the sagittal plane torque measurement, 0.8 per cent of the full-scale load. The trial-to-trial variability analysis of the device using deadweights provided intra-class correlation coefficients of higher than 0.99, suggesting excellent reliability. The cross-talk analysis of the device indicated maximum cross-talks of 1.7 per cent and 3.4 per cent when the system was subjected to flexion-extension and lateral bending torques respectively. The trial-to-trial variability of the system during in-vivo strength measurement tests resulted in good to excellent reliability, with intra-class correlation coefficients ranging from 0.69 to 0.91. The results of the maximum

  10. 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.

  11. KENNEDY SPACE CENTER, FLA. - International Space Station elements being processed for launch on upcoming Space Shuttle flights, including the Japanese Experiment Module (JEM) pressurized module, line the walls of the high bay in the Space Station Processing Facility. The JEM pressurized module, named "Kibo" (Hope), arrived at KSC on June 4. It is Japan's primary contribution to the Station.

    NASA Image and Video Library

    2003-06-19

    KENNEDY SPACE CENTER, FLA. - International Space Station elements being processed for launch on upcoming Space Shuttle flights, including the Japanese Experiment Module (JEM) pressurized module, line the walls of the high bay in the Space Station Processing Facility. The JEM pressurized module, named "Kibo" (Hope), arrived at KSC on June 4. It is Japan's primary contribution to the Station.

  12. Optical Imaging and Spectroscopy of the Edge-on Sbc Galaxy UGC 10043: Evidence for a Galactic Wind and a Peculiar Triaxial Bulge

    NASA Astrophysics Data System (ADS)

    Matthews, L. D.; de Grijs, R.

    2004-07-01

    We present new optical imaging and spectroscopy of the peculiar, edge-on Sbc galaxy UGC 10043. Using the WIYN telescope, we have obtained B, R, and Hα+[NII] images, together with DensePak integral field spectroscopic measurements of the stellar Ca II infrared triplet and the Hα and [N II] lines from the ionized gas. The imaging observations show that the inner bulge of UGC 10043 (a<=7.5") is elongated perpendicular to the galaxy major axis. At larger r the bulge isophotes twist to become oblate and nearly circular, suggesting the bulge is triaxial. The bulge shows no clear evidence for rotation about either its major or minor axis. The inner, southwestern quadrant of the bulge is girdled by a narrow dust lane parallel to the minor axis; unsharp masking reveals that this minor-axis dust lane may be part of an inner polar ring, although we find no unambiguous kinematic evidence of orthogonally rotating material. The stellar disk of UGC 10043 has a rather low optical surface brightness [μ(0)R,i~23.2 mag arcsec-2], a small scale height (hz=395 pc for D=33.4 Mpc), and a mild integral sign warp. A dusty, inner disk component that appears tilted relative to the outlying disk is also seen. The Hα and [N II] emission lines in UGC 10043 resolve into multiple velocity components, indicating the presence of a large-scale galactic wind with an outflow velocity of Vout>~104 km s-1. Hα+[NII] imaging reaffirms this picture by revealing ionized gas extended to |z|~3.5 kpc in the form of a roughly biconical structure. The [N II]/Hα line intensity ratio increases with increasing distance from the plane, reaching values as high as 1.7. Unlike most galaxies with large-scale winds, UGC 10043 has only a modest global star formation rate (<~1 Msolar yr-1), implying the wind is powered by a rather feeble central starburst. We discuss evolutionary scenarios that could account for both the structural complexities of UGC 10043 and its large-scale wind. The most plausible scenarios

  13. 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.

  14. 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.

  15. 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.

  16. Preliminary Investigations of Creep Strain of Neogene Clay from Warsaw in Drained Triaxial Tests Assisted by Computed Microtomography

    NASA Astrophysics Data System (ADS)

    Kaczmarek, Łukasz Dominik; Dobak, Paweł Józef; Kiełbasiński, Kamil

    2017-06-01

    The study concerns soil creep deformation in multistage triaxial stress tests under drained conditions. High resolution X-ray computed microtomography (XμCT) was involved in structure recognition before and after triaxial tests. Undisturbed Neogene clay samples, which are widespread in central Poland, were used in this study. XμCT was used to identify representative sample series and informed the detection and rejection of unreliable ones. Maximum deviatoric stress for in situ stress confining condition was equal 95.1 kPa. This result helped in the design of further multistage investigations. The study identified the rheological strain course, which can be broken down into three characterizations: decreasing creep strain rate, transitional constant creep velocity, and accelerating creep deformation. The study found that due to multistage creep loading, the samples were strengthened. Furthermore, there is a visibly "brittle" character of failure, which may be the consequence of the microstructure transformation as a function of time as well as collapse of voids. Due to the glacial tectonic history of the analyzed samples, the reactivation of microcracks might also serve as an explanation. The number of the various sizes of shear planes after failure is confirmed by XμCT overexposure.

  17. A three-step calibration method for tri-axial field sensors in a 3D magnetic digital compass

    NASA Astrophysics Data System (ADS)

    Zhu, Xiaoning; Zhao, Ta; Cheng, Defu; Zhou, Zhijian

    2017-04-01

    In a 3D magnetic compass, it is important to calibrate the tri-axial magnetometers and accelerometers so the compass will provide accurate heading and attitude information. Previous researchers have used two methods to calibrate these two field sensors separately, i.e. the classic independent ellipsoid fitting method and the independent dot product invariant method, respectively. Both methods are easy to use, and no highly accurate, external equipment is required. However, self-calibration with ellipsoid fitting has the disadvantage that it interfuses an orthogonal matrix, and the dot product invariant method requires the use of pre-calibrated internal field sensors, which may be unavailable in many cases. In this paper, we have introduced and unified an error model of two tri-axial field sensors. Accordingly, the orthogonal matrix caused by ellipsoid fitting was mathematically proved to be the combination of two sources, the mounting misalignment and the rotation misalignment. Moreover, a new method, which we call optimal resultant vector, was proposed to further calibrate multi-sensor systems on the basis of ellipsoid fitting and dot product invariant methods, establishing a new, three-step calibration method. The superiority of the proposed method over the state-of-the-art approaches were demonstrated by simulations and a 3D compass experiment.

  18. 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.

  19. Research on the deformation and failure evolution of sandstone under triaxial compression based on PFC2D

    NASA Astrophysics Data System (ADS)

    Yang, X. B.; Han, X. X.; Zhou, T. B.; Liu, E. L.

    2017-04-01

    Through the comparative analysis of the results of the triaxial compression experiments of sandstone and the numerical simulation results of particle flow code PFC2D under the same conditions, the typical simulation curve and the corresponding simulation process were selected to analyze the evolution characteristics of the surface deformation field, the evolution characteristics of the velocity field and displacement field of the deformation localization bands of sandstone under triaxial compression. Research results show that the changes of the velocities and displacements of deformation localization bands corresponds to the change of stress during compression; In the same deformation localization band, the dislocation velocities are always in the same direction, but in the direction vertical to the localization band, the localization band sometimes squeezes and sometimes stretches; At different positions of the same deformation localization band, the dislocation velocities and extrusion velocities are both different at the same time; In the post-peak stage of loading, along the same deformation localization band, the dislocation displacements close to both loaded ends are generally greater than the ones near to the middle position of the specimen, the stretching displacements close to both loaded ends are generally smaller than the ones near to the middle position of the specimen.

  20. 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.

  1. Time dependent voiding mechanisms in polyamide 6 submitted to high stress triaxiality: experimental characterisation and finite element modelling

    NASA Astrophysics Data System (ADS)

    Selles, Nathan; King, Andrew; Proudhon, Henry; Saintier, Nicolas; Laiarinandrasana, Lucien

    2017-08-01

    Double notched round bars made of semi-crystalline polymer polyamide 6 (PA6) were submitted to monotonic tensile and creep tests. The two notches had a root radius of 0.45 mm, which imposes a multiaxial stress state and a state of high triaxiality in the net (minimal) section of the specimens. Tests were carried out until the failure occurred from one of the notches. The other one, unbroken but deformed under steady strain rate or steady load, was inspected using the Synchrotron Radiation Computed Tomography (SRCT) technique. These 3D through thickness inspections allowed the study of microstructural evolution at the peak stress for the monotonic tensile test and at the beginning of the tertiary creep for the creep tests. Cavitation features were assessed with a micrometre resolution within the notched region. Spatial distributions of void volume fraction ( Vf) and void morphology were studied. Voiding mechanisms were similar under steady strain rates and steady loads. The maximum values of Vf were located between the axis of revolution of the specimens and the notch surface and voids were considered as flat cylinders with a circular basis perpendicular to the loading direction. A model, based on porous plasticity, was used to simulate the mechanical response of this PA6 material under high stress triaxiality. Both macroscopic behaviour (loading curves) and voiding micro-mechanisms (radial distributions of void volume fraction) were accurately predicted using finite element simulations.

  2. 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.

  3. 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

  4. Three novel germ-line VHL mutations in Hungarian von Hippel-Lindau patients, including a nonsense mutation in a fifteen-year-old boy with renal cell carcinoma

    PubMed Central

    2013-01-01

    Background Von Hippel-Lindau disease is an autosomal dominantly inherited highly penetrant tumor syndrome predisposing to retinal and central nervous system hemangioblastomas, renal cell carcinoma and phaeochromocytoma among other less frequent complications. Methods Molecular genetic testing of the VHL gene was performed in five unrelated families affetced with type I VHL disease, including seven patients and their available family members. Results Molecular genetic investigations detected three novel (c.163 G > T, c.232A > T and c.555C > A causing p.Glu55X, p.Asn78Tyr and p.Tyr185X protein changes, respectively) and two previously described (c.340 + 1 G > A and c.583C > T, resulting in p.Gly114AspfsX6 and p.195GlnX protein changes, respectively) germline point mutations in the VHL gene. Molecular modeling of the VHL-ElonginC-HIF-1alpha complex predicted that the p.Asn78Tyr amino acid exchange remarkably alters the 77-83 loop structure of VHL protein and destabilizes the VHL-HIF-1alpha complex suggesting that the mutation causes type I phenotype and has high risk to associate to renal cell carcinoma. The novel p.55X nonsense mutation associated to bilateral RCC and retinal angioma in a 15-year-old male patient. Conclusion We describe the earliest onset renal cell carcinoma in VHL disease reported so far in a 15-year-old boy with a nonsense VHL mutation. Individual tailoring of screening schedule based on molecular genetic status should be considered in order to diagnose serious complications as early as possible. Our observations add to the understanding of genotype-phenotype correlation in VHL disease and can be useful for genetic counseling and follow-up of VHL patients. PMID:23298237

  5. 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

  6. Investigation on the Permeability Evolution of Gypsum Interlayer Under High Temperature and Triaxial Pressure

    NASA Astrophysics Data System (ADS)

    Tao, Meng; Yechao, You; Jie, Chen; Yaoqing, Hu

    2017-08-01

    The permeability of the surrounding rock is a critical parameter for the designing and assessment of radioactive waste disposal repositories in the rock salt. Generally, in the locations that are chosen for radioactive waste storage, the bedded rock salt is a sedimentary rock that contains NaCl and Na2SO4. Most likely, there are also layers of gypsum ( {CaSO}_{ 4} \\cdot 2 {H}_{ 2} {O)} present in the salt deposit. Radioactive wastes emit a large amount of heat and hydrogen during the process of disposal, which may result in thermal damage of the surrounding rocks and cause a great change in their permeability and tightness. Therefore, it is necessary to investigate the permeability evolution of the gypsum interlayer under high temperature and high pressure in order to evaluate the tightness and security of the nuclear waste repositories in bedded rock salt. In this study, a self-designed rock triaxial testing system by which high temperature and pressure can be applied is used; the μCT225kVFCB micro-CT system is also employed to investigate the permeability and microstructure of gypsum specimens under a constant hydrostatic pressure of 25 MPa, an increasing temperature (ranging from 20 to 650 °C), and a variable inlet gas pressure (1, 2, 4, 6 MPa). The experimental results show: (a) the maximum permeability measured during the whole experiment is less than 10-17 m2, which indicates that the gypsum interlayer has low permeability under high temperature and pressure that meet the requirements for radioactive waste repository. (b) Under the same temperature, the permeability of the gypsum specimen decreases at the beginning and then increases as the pore pressure elevates. When the inlet gas pressure is between 0 and 2 MPa, the Klinkenberg effect is very pronounced. Then, as the pore pressure increases, the movement behavior of gas molecules gradually changes from free motion to forced directional motion. So the role of free movement of gas molecules gradually

  7. Nuclear reactor overflow line

    DOEpatents

    Severson, Wayne J.

    1976-01-01

    The overflow line for the reactor vessel of a liquid-metal-cooled nuclear reactor includes means for establishing and maintaining a continuous bleed flow of coolant amounting to 5 to 10% of the total coolant flow through the overflow line to prevent thermal shock to the overflow line when the reactor is restarted following a trip. Preferably a tube is disposed concentrically just inside the overflow line extending from a point just inside the reactor vessel to an overflow tank and a suction line is provided opening into the body of liquid metal in the reactor vessel and into the annulus between the overflow line and the inner tube.

  8. 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.

  9. Design of triaxial test with controlled suction: measure of strainConception d'un essai triaxial à succion contrôlée : mesure des déformations

    NASA Astrophysics Data System (ADS)

    Gasc-Barbier, Muriel; Cosenza, Philippe; Ghoreychi, Mehdi; Chanchole, Serge; Tessier, Daniel

    2000-01-01

    Experimental study of mechanical behaviour of clayey materials under hygrometric condition is usually performed either on unloaded samples or by means of classical oedometer tests used in soil mechanics. Such methods are not well adapted to hard deep clayey rocks with little deformability, porosity and permeability. Moreover, stress and strain tensors having a significant effect on hygro-mechanical behaviour and properties cannot be measured and investigated appropriately by classical tests. This is why a specific triaxial test was designed in which the sample is surrounded by a fiber glass tissue allowing air circulation and then by silicon on which confining pressure is applied. Thus, equilibrium between air and sample was reduced. Stress and strain tensors were also measured in time on the sample subjected to a mechanical loading and to a controlled suction. After presentation of the test, preliminary results are given.

  10. Improvement of aerosol optical depth retrieval from MODIS spectral reflectance over the global ocean using new aerosol models archived from AERONET inversion data and tri-axial ellipsoidal dust database data

    NASA Astrophysics Data System (ADS)

    Lee, J.; Kim, J.; Yang, P.

    2011-12-01

    New over-ocean aerosol models are developed by integrating extensive AERONET inversion data and a database of the optical properties of tri-axial ellipsoidal dust particles. These models allow more accurate retrieval of aerosol optical depth (AOD) from the Moderate Resolution Imaging Spectroradiometer (MODIS) for high AOD cases. Spectral AOD, single scattering albedo (SSA), and phase function, which are used to calculate a lookup table (LUT), are archived by combining inversion data from Aerosol Robotic Network (AERONET) Sun/sky radiometers and single-scattering properties from the tri-axial ellipsoidal dust database. The aerosol models are categorized from the AERONET data using the fine-mode fraction (FMF) at 550 nm and the SSA at 440 nm to resolve a variety of aerosol types throughout the globe. For each aerosol model, the changes in aerosol optical properties (AOP) are included as functions of AOD. Comparisons of AODs between AERONET and MODIS for the period from 2003 to 2010 show that the new aerosol models improve correlation compared to the MODIS Collection 5 products with a Pearson coefficient of 0.93 and a regression slope of 0.99 compared to 0.92 and 0.85, respectively, for the MODIS operational algorithm. Moreover, use of the new algorithms increases the percentage of data within an expected error of ± (0.03 + 0.05 × AOD) from 62 to 64% overall and from 39 to 51% for high AOD cases (AOD > 0.3). Errors in the retrieved AOD are characterized further with respect to the Ångström exponent (AE), scattering angle (Θ), and air mass factor (AMF). Overall, the new aerosol models reduce systematic errors in AOD retrieval compared with the Collection 5 data due to realistic AOP assumptions. In particular, the scattering angle dependence of the retrieved AOD for dust cases is significantly mitigated due to improved treatment of the nonsphericity of dust particles by the new algorithm.

  11. Design modification and optimisation of the perfusion system of a tri-axial bioreactor for tissue engineering.

    PubMed

    Hussein, Husnah; Williams, David J; Liu, Yang

    2015-07-01

    A systematic design of experiments (DOE) approach was used to optimize the perfusion process of a tri-axial bioreactor designed for translational tissue engineering exploiting mechanical stimuli and mechanotransduction. Four controllable design parameters affecting the perfusion process were identified in a cause-effect diagram as potential improvement opportunities. A screening process was used to separate out the factors that have the largest impact from the insignificant ones. DOE was employed to find the settings of the platen design, return tubing configuration and the elevation difference that minimise the load on the pump and variation in the perfusion process and improve the controllability of the perfusion pressures within the prescribed limits. DOE was very effective for gaining increased knowledge of the perfusion process and optimizing the process for improved functionality. It is hypothesized that the optimized perfusion system will result in improved biological performance and consistency.

  12. Influence of Deformation Stress Triaxiality on Microstructure and Microhardness of Pure Copper Processed by Simultaneous Torsion and Tension

    NASA Astrophysics Data System (ADS)

    Zhao, Chen; Li, Fuguo; Li, Jinghui; Ma, Xinkai; Wan, Qiong; Tong, Tengteng

    2017-08-01

    Simultaneous torsion and tension deformation (STTD) modes were applied on commercial pure copper to investigate the influence of stress triaxiality on microstructure evolution and hardness distribution at room temperature. STTD was divided into pure torsion (PT, a special STTD) and general STTD according to tension loading. Microstructure evolution was observed by optical microscopy, electron backscattering diffraction and transmission electron microscopy. The microhardness distribution was measured on the cross section, and the fracture morphology was observed by scanning electron microscopy. Microstructure observations show that ultrafine grains are separated by high-angle grain boundaries. Microhardness measurements exhibit hardness increased more significantly and uniformly in the specimen processed by general STTD mode than PT mode. Additionally, the fracture morphology indicates the fracture mechanism is different between STTD and PT.

  13. Triaxial-Stress-Induced Homogeneous Hysteresis-Free First-Order Phase Transformations with Stable Intermediate Phases

    NASA Astrophysics Data System (ADS)

    Levitas, Valery I.; Chen, Hao; Xiong, Liming

    2017-01-01

    Starting with thermodynamic predictions and following with molecular dynamics simulations, special triaxial compression-tension states were found for which the stresses for the instability of the crystal lattice of silicon (Si) are the same for direct and reverse phase transformations (PTs) between semiconducting Si I and metallic Si II phases. This leads to unique homogeneous and hysteresis-free first-order PTs, for which each intermediate crystal lattice along the transformation path is in indifferent thermodynamic equilibrium and can be arrested and studied by fixing the strain in one direction. By approaching these stress states, a traditional two-phase system continuously transforms to homogenous intermediate phases. Zero hysteresis and homogeneous transformations are the optimal property for various PT applications, which drastically reduce damage and energy dissipation.

  14. Self-cementing properties of crushed demolished concrete in unbound layers: results from triaxial tests and field tests.

    PubMed

    Arm, M

    2001-01-01

    A 2-year study is underway to evaluate the expected growth in stiffness in layers of crushed concrete from demolished structures. This growth is said to be a result of self-cementing properties. The study consists of repeated load triaxial tests on manufactured specimens after different storing time together with falling weight deflectometer, FWD, measurements on test sections. Results so far show a clear increase with time in resilient modulus and in back-calculated layer modulus for all concrete materials. The increase is the largest in the first months and then diminishes. The field measurements show a more considerable growth in stiffness than the laboratory tests, with a doubled value two years after construction. Comparative investigations on natural aggregates, mostly crushed granite do not show any growth in stiffness, neither in the laboratory nor in the field. Consequences for the choice of design modulus are discussed.

  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. 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.

  17. Triaxial-Stress-Induced Homogeneous Hysteresis-Free First-Order Phase Transformations with Stable Intermediate Phases.

    PubMed

    Levitas, Valery I; Chen, Hao; Xiong, Liming

    2017-01-13

    Starting with thermodynamic predictions and following with molecular dynamics simulations, special triaxial compression-tension states were found for which the stresses for the instability of the crystal lattice of silicon (Si) are the same for direct and reverse phase transformations (PTs) between semiconducting Si I and metallic Si II phases. This leads to unique homogeneous and hysteresis-free first-order PTs, for which each intermediate crystal lattice along the transformation path is in indifferent thermodynamic equilibrium and can be arrested and studied by fixing the strain in one direction. By approaching these stress states, a traditional two-phase system continuously transforms to homogenous intermediate phases. Zero hysteresis and homogeneous transformations are the optimal property for various PT applications, which drastically reduce damage and energy dissipation.

  18. Using tri-axial acceleration data to identify behavioral modes of free-ranging animals: general concepts and tools illustrated for griffon vultures

    PubMed Central

    Nathan, Ran; Spiegel, Orr; Fortmann-Roe, Scott; Harel, Roi; Wikelski, Martin; Getz, Wayne M.

    2012-01-01

    Summary Integrating biomechanics, behavior and ecology requires a mechanistic understanding of the processes producing the movement of animals. This calls for contemporaneous biomechanical, behavioral and environmental data along movement pathways. A recently formulated unifying movement ecology paradigm facilitates the integration of existing biomechanics, optimality, cognitive and random paradigms for studying movement. We focus on the use of tri-axial acceleration (ACC) data to identify behavioral modes of GPS-tracked free-ranging wild animals and demonstrate its application to study the movements of griffon vultures (Gyps fulvus, Hablizl 1783). In particular, we explore a selection of nonlinear and decision tree methods that include support vector machines, classification and regression trees, random forest methods and artificial neural networks and compare them with linear discriminant analysis (LDA) as a baseline for classifying behavioral modes. Using a dataset of 1035 ground-truthed ACC segments, we found that all methods can accurately classify behavior (80–90%) and, as expected, all nonlinear methods outperformed LDA. We also illustrate how ACC-identified behavioral modes provide the means to examine how vulture flight is affected by environmental factors, hence facilitating the integration of behavioral, biomechanical and ecological data. Our analysis of just over three-quarters of a million GPS and ACC measurements obtained from 43 free-ranging vultures across 9783 vulture-days suggests that their annual breeding schedule might be selected primarily in response to seasonal conditions favoring rising-air columns (thermals) and that rare long-range forays of up to 1750 km from the home range are performed despite potentially heavy energetic costs and a low rate of food intake, presumably to explore new breeding, social and long-term resource location opportunities. PMID:22357592

  19. Using tri-axial acceleration data to identify behavioral modes of free-ranging animals: general concepts and tools illustrated for griffon vultures.

    PubMed

    Nathan, Ran; Spiegel, Orr; Fortmann-Roe, Scott; Harel, Roi; Wikelski, Martin; Getz, Wayne M

    2012-03-15

    Integrating biomechanics, behavior and ecology requires a mechanistic understanding of the processes producing the movement of animals. This calls for contemporaneous biomechanical, behavioral and environmental data along movement pathways. A recently formulated unifying movement ecology paradigm facilitates the integration of existing biomechanics, optimality, cognitive and random paradigms for studying movement. We focus on the use of tri-axial acceleration (ACC) data to identify behavioral modes of GPS-tracked free-ranging wild animals and demonstrate its application to study the movements of griffon vultures (Gyps fulvus, Hablizl 1783). In particular, we explore a selection of nonlinear and decision tree methods that include support vector machines, classification and regression trees, random forest methods and artificial neural networks and compare them with linear discriminant analysis (LDA) as a baseline for classifying behavioral modes. Using a dataset of 1035 ground-truthed ACC segments, we found that all methods can accurately classify behavior (80-90%) and, as expected, all nonlinear methods outperformed LDA. We also illustrate how ACC-identified behavioral modes provide the means to examine how vulture flight is affected by environmental factors, hence facilitating the integration of behavioral, biomechanical and ecological data. Our analysis of just over three-quarters of a million GPS and ACC measurements obtained from 43 free-ranging vultures across 9783 vulture-days suggests that their annual breeding schedule might be selected primarily in response to seasonal conditions favoring rising-air columns (thermals) and that rare long-range forays of up to 1750 km from the home range are performed despite potentially heavy energetic costs and a low rate of food intake, presumably to explore new breeding, social and long-term resource location opportunities.

  20. Asteroid (16) Psyche: Triaxial Ellipsoid Dimensions and Rotational Pole from Keck II NIRC2 AO Images and Keck I OSIRIS Images

    NASA Astrophysics Data System (ADS)

    Drummond, Jack D.; Conrad, Al; Reddy, Vishnu; de Kleer, Katherine R.; Adamkovics, Mate; de Pater, Imke; Merline, William J.; Tamblyn, Peter

    2016-10-01

    Adaptive optics (AO) images of asteroid (16) Psyche obtained at 4 epochs with the NIRC2 camera at the 10m W. M. Keck Observatory (Keck II) on UT 2015 December 25 lead to triaxial ellipsoid diameters of 279±4 x 230±2 x 195±14 km, and a rotational pole at RA=29° and Dec=-2°. Adding 6 more epochs obtained nearly simultaneously with the OSIRIS system at Keck I, as well as two more epochs from Keck II in 2009, yields diameters of 273±2 x 232±2 x 165±3 km, and a pole at RA=37° and Dec=+1°. (Errors are formal fit parameter uncertainties; an additional 4% uncertainty is possible from systematic biases.) The differing perspectives between 2015 (sub-Earth latitude Θ=-50°) and 2009 (Θ=-6°) improves primarily the c dimension and the location of the rotational pole, but illustrates how well images from even a single night can determine the size, shape, and pole of an asteroid. The 2015 observations were obtained as part of a campaign to study Psyche with many techniques over a few months, including radar from Arecibo and images from Magellan.These handful of images show the same rugged outline as the radius vector model available on the DAMIT website, constructed from many lightcurves and scaled by previous Keck AO images. In fact Psyche has rotated some 125,350 times between the first lightcurve in 1955 and our 2015 AO images, exactly 60 years apart to the day. Since the asteroid has such a high obliquity, these lightcurves have scanned well into both northern and southern hemispheres. The difference between the pole derived from our images and the radius vector model pole is only 7°, and the mean diameters of Psyche are 219 and 211 km, respectively.