WorldWideScience

Sample records for zig-zag spin ladders

  1. Magnetic properties of the two-leg zig-zag ladder in quantum spin system NH4CuCl3

    International Nuclear Information System (INIS)

    Raksa, Teguh Yoga; Kurniawan, Budhy

    2002-01-01

    Numerical analysis of the two-leg zig-zag ladder as a single chain with next-nearest neighbour interactions has been formulated by Cabra (1999) with the following Hamiltonian. Other formulation for two leg zig-zag ladder with dimerized chains and coupling between the chains. From these formulations, we study the closing of the gap at zero magnetization by means of the fine-tuning mechanism and disappearance of the 1/2 plateau (gap) at finite by alternating dimerization of the chains along the rungs. We also described NH 4 CuCI 3 under high magnetic fields in a two-leg system

  2. The Zig Zag Machine. Module 14.

    Science.gov (United States)

    South Carolina State Dept. of Education, Columbia. Office of Vocational Education.

    This module on the zig zag machine, one in a series dealing with industrial sewing machines, their attachments, and operation, covers one topic: performing special operations on the zig zag machine. These components are provided: an introduction, directions, an objective, learning activities, student information, a student self-check, and a…

  3. Interconversion of Fischer and Zig-Zag Projections Learning ...

    Indian Academy of Sciences (India)

    IAS Admin

    Stereochemistry, conforma- tional analysis, hands-on learn- ing, Fischer projections, zig-zag projection, C–C bond rotations. Interconversion of Fischer and Zig-Zag Projections. Learning Stereochemistry with the Help of Hands. Visualization of molecules in three dimensions is an important aspect of organic chemistry.

  4. Phase diagram study of a dimerized spin-S zig–zag ladder

    International Nuclear Information System (INIS)

    Matera, J M; Lamas, C A

    2014-01-01

    The phase diagram of a frustrated spin-S zig–zag ladder is studied through different numerical and analytical methods. We show that for arbitrary S, there is a family of Hamiltonians for which a fully-dimerized state is an exact ground state, being the Majumdar–Ghosh point for a particular member of the family. We show that the system presents a transition between a dimerized phase to a Néel-like phase for S = 1/2, and spiral phases can appear for large S. The phase diagram is characterized by means of a generalization of the usual mean field approximation. The novelty in the present implementation is to consider the strongest coupled sites as the unit cell. The gap and the excitation spectrum is analyzed through the random phase approximation. Also, a perturbative treatment to obtain the critical points is discussed. Comparisons of the results with numerical methods like the Density Matrix Renormalization Group are also presented. (paper)

  5. Disease susceptibiliy in the zig-zag model of host-microbe Interactions: only a consequence of immune suppression?

    OpenAIRE

    Keller, Harald; Boyer, Laurent; Abad, Pierre

    2016-01-01

    For almost ten years, the Zig-Zag model has provided a convenient framework for explaining the molecular bases of compatibility and incompatibility in plant-microbe interactions (Jones and Dangl, 2006). According to the Zig-Zag model, disease susceptibility is a consequence of the suppression of host immunity during the evolutionary arms race between plants and pathogens. The Zig-Zag model thus fits well with biotrophic interactions, but is less applicable to interactions involving pathogens ...

  6. Zig-zag version of the Frenkel-Kontorova model

    DEFF Research Database (Denmark)

    Christiansen, Peter Leth; Savin, A.V.; Zolotaryuk, Alexander

    1996-01-01

    We study a generalization of the Frenkel-Kontorova model which describes a zig-zag chain of particles coupled by both the first- and second-neighbor harmonic forces and subjected to a planar substrate with a commensurate potential relief. The particles are supposed to have two degrees of freedom...

  7. Studi Kinerja Solar Water Heater Dengan Aliran Zig-zag Beralur Balok

    Directory of Open Access Journals (Sweden)

    M. Rizki Ikhsan

    2017-05-01

    Full Text Available Solar energy can be used for water heating by using solar water heater application. Therefore, its still needs some modification due to its low efficiency. This modification can be done by replacing the conventional plate of solar collectors into a double plate with a zig-zag pattern. The results shown that along with the decreasing of water flow rates could significantly increase the useful energy (Qu. Initial temperature of water inlet could affect the generated maximum temperature. The highest mean efficiencies of double plate solar water heater with a zig-zag grooved beams pattern of 49.11% was gained in the flow rate of 700 mL / min.

  8. High-performance zig-zag and meander inductors embedded in ferrite material

    International Nuclear Information System (INIS)

    Stojanovic, Goran; Damnjanovic, Mirjana; Desnica, Vladan; Zivanov, Ljiljana; Raghavendra, Ramesh; Bellew, Pat; Mcloughlin, Neil

    2006-01-01

    This paper describes the design, modeling, simulation and fabrication of zig-zag and meander inductors embedded in low- or high-permeability soft ferrite material. These microinductors have been developed with ceramic coprocessing technology. We compare the electrical properties of zig-zag and meander inductors structures installed as surface-mount devices. The equivalent model of the new structures is presented, suitable for design, circuit simulations and for prediction of the performance of proposed inductors. The relatively high impedance values allow these microinductors to be used in high-frequency suppressors. The components were tested in the frequency range of 1 MHz-3 GHz using an Agilent 4287A RF LCR meter. The measurements confirm the validity of the analytical model

  9. The Effect of Acceleration Sprint and Zig-zag Drill Combination to Increase Students’ Speed and Agility

    Science.gov (United States)

    Bana, O.; Mintarto, E.; Kusnanik, N. W.

    2018-01-01

    The purpose of this research is to analyze the following factors: (1) how far the effect of exercise acceleration sprint on the speed and agility (2) how much influence the zig-zag drill combination to the speed and agility (3) and is there any difference between the effects of exercise acceleration sprint and practice zig-zag drill combination of the speed and agility. This research is quantitative with quasi-experimental approach. The design of this study is matching only design.This study was conducted on 33 male students who take part in extracurricular and divided into 3 groups with 11 students in each group. Group 1 was given training of acceleration sprint, group 2 was given zig-zag training combination drills of conventional and exercises for group 3, for 8 weeks. The data collection was using sprint 30 meter to test the speed and agility t-test to test agility. Data were analyzed using t-test and analysis of variance. The conclusion of the research is (1) there is a significant effect of exercise acceleration sprint for the speed and agility, (2) there is a significant influence combination zig-zag drills, on speed and agility (3) and exercise acceleration sprint have more effect on the speed and agility.

  10. Quench dynamics of two coupled zig-zag ion chains

    Energy Technology Data Exchange (ETDEWEB)

    Klumpp, Andrea, E-mail: andrea.klumpp@physnet.uni-hamburg.de [Zentrum für Optische Quantentechnologien, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany); Liebchen, Benno [SUPA, School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3FD (United Kingdom); Schmelcher, Peter [Zentrum für Optische Quantentechnologien, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany); The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg (Germany)

    2016-08-06

    We explore the non-equilibrium dynamics of two coupled zig-zag chains of trapped ions in a double well potential. Following a quench of the potential barrier between both wells, the induced coupling between both chains due to the long-range interaction of the ions leads to the complete loss of order in the radial direction. The resulting dynamics is however not exclusively irregular but leads to phases of motion during which various ordered structures appear with ions arranged in arcs, lines and crosses. We quantify the emerging order by introducing a suitable measure and complement our analysis of the ion dynamics using a normal mode analysis showing a decisive population transfer between only a few distinguished modes. - Highlights: • Novel dynamical phenomenology of two coupled zig-zag ion chains following a trap quench is explored. • Transient ordered ion configurations are unraveled in non-equilibrium dynamics dominated by irregular behavior. • A measure for the diagnosis of this transient order is introduced and applied. • Energy transfer between a few eigen modes is identified as the key mechanism for the occurrence of the ordered configurations.

  11. A zig-zag oscilloscope presentation for detonation velocity measurement in explosives

    Energy Technology Data Exchange (ETDEWEB)

    Leger, E. G.; Park, K.

    1958-01-15

    Cathode ray tube presentations of various types, including zig-zag, raster, and spiral were devised over the past decade to increase the time resolution of discrete events recorded on the trace. The object of these presentations is to lengthen the effective trace by folding it in various ways across the face of the cathode ray tube.

  12. The effect of laser beam size in a zig-zag collimator on transverse ...

    Indian Academy of Sciences (India)

    The effect of size of a cooling laser beam in a zig-zag atomic beam collimator on trans- ... resolution spectroscopy, many-body physics, precision measurements, atom lithogra- ..... torr) at a distance of 180 cm from the Kr gas inlet chamber.

  13. An Implementation of RC4+ Algorithm and Zig-zag Algorithm in a Super Encryption Scheme for Text Security

    Science.gov (United States)

    Budiman, M. A.; Amalia; Chayanie, N. I.

    2018-03-01

    Cryptography is the art and science of using mathematical methods to preserve message security. There are two types of cryptography, namely classical and modern cryptography. Nowadays, most people would rather use modern cryptography than classical cryptography because it is harder to break than the classical one. One of classical algorithm is the Zig-zag algorithm that uses the transposition technique: the original message is unreadable unless the person has the key to decrypt the message. To improve the security, the Zig-zag Cipher is combined with RC4+ Cipher which is one of the symmetric key algorithms in the form of stream cipher. The two algorithms are combined to make a super-encryption. By combining these two algorithms, the message will be harder to break by a cryptanalyst. The result showed that complexity of the combined algorithm is θ(n2 ), while the complexity of Zig-zag Cipher and RC4+ Cipher are θ(n2 ) and θ(n), respectively.

  14. Soliton Analysis in Complex Molecular Systems: A Zig-Zag Chain

    Science.gov (United States)

    Christiansen, P. L.; Savin, A. V.; Zolotaryuk, A. V.

    1997-06-01

    A simple numerical method for seeking solitary wavesolutions of a permanent profile in molecular systems of big complexity is presented. The method is essentially based on the minimization of a finite-dimensional function which is chosen under an appropriate discretization of time derivatives in equations of motion. In the present paper, it is applied to a zig-zag chain backbone of coupled particles, each of which has twodegrees of freedom (longitudinal and transverse). Both topological and nontopological soliton solutions are treated for this chain when it is (i) subjected to a two-dimensional periodic substrate potential or (ii) considered as an isolated object, respectively. In the first case, which may be considered as a zig-zag generalization of the Frenkel-Kontorova chain model, two types of kink solutions with different topological charges, describing vacancies of one or two atoms (I- or II-kinks) and defects with excess one or two atoms in the chain (I- or II-antikinks), have been found. The second case (isolated chain) is a generalization of the well-known Fermi-Pasta-Ulam chain model, which takes into account transverse degrees of freedom of the chain molecules. Two types of stable nontopological soliton solutions which describe either (i) a supersonic solitary wave of longitudinal stretching accompanied by transverse slendering or (ii) supersonic pulses of longitudinal compression propagating together with localized transverse thickening (bulge) have been obtained.

  15. Critical surface phase of α2(2 × 4) reconstructed zig-zag chains on InAs(001)

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Xiang [Department of Electronic Information Science and Technology, Guizhou University, Guizhou, Guiyang 550025 (China); Zhou, Xun [Department of Electronic Information Science and Technology, Guizhou University, Guizhou, Guiyang 550025 (China); School of Physics and Electronics Science, Guizhou Normal University, Guizhou, Guiyang 550001 (China); Wang, Ji-Hong [Department of Electronic Information Science and Technology, Guizhou University, Guizhou, Guiyang 550025 (China); Luo, Zi-Jiang [Department of Electronic Information Science and Technology, Guizhou University, Guizhou, Guiyang 550025 (China); School of Education Administration, Guizhou University of Finance and Economics, Guizhou, Guiyang 550004 (China); Zhou, Qing; Liu, Ke; Hu, Ming-Zhe [Department of Electronic Information Science and Technology, Guizhou University, Guizhou, Guiyang 550025 (China); Ding, Zhao, E-mail: zding@gzu.edu.cn [Department of Electronic Information Science and Technology, Guizhou University, Guizhou, Guiyang 550025 (China)

    2014-07-01

    The critical condition for InAs(001) surface phase transition has been studied, the surface phase transition of InAs(001) showed discontinuity with hysteresis cycle as a function of substrate temperature. A mixed reconstruction surface and zig-zag chain α2(2 × 4) reconstruction surface have been observed by scanning tunneling microscopy. Considering the interaction and dynamics of surface arsenic atoms, the zig-zag chains of α2(2 × 4) reconstruction were found to be actually caused by the selective adsorption and desorption of surface arsenic dimers, they played a critical role in the surface phase transition between (2 × 4) and (4 × 2). - Highlights: • Discontinuous surface phase transition phenomena on the flat InAs(001) surface • Nanoscale InAs(001) surface observed by scanning tunneling microscopy • “Zig-Zag” chains of α2(2 × 4) reconstruction • Critical role in the surface phase transition between (2 × 4) and (4 × 2)

  16. Critical surface phase of α2(2 × 4) reconstructed zig-zag chains on InAs(001)

    International Nuclear Information System (INIS)

    Guo, Xiang; Zhou, Xun; Wang, Ji-Hong; Luo, Zi-Jiang; Zhou, Qing; Liu, Ke; Hu, Ming-Zhe; Ding, Zhao

    2014-01-01

    The critical condition for InAs(001) surface phase transition has been studied, the surface phase transition of InAs(001) showed discontinuity with hysteresis cycle as a function of substrate temperature. A mixed reconstruction surface and zig-zag chain α2(2 × 4) reconstruction surface have been observed by scanning tunneling microscopy. Considering the interaction and dynamics of surface arsenic atoms, the zig-zag chains of α2(2 × 4) reconstruction were found to be actually caused by the selective adsorption and desorption of surface arsenic dimers, they played a critical role in the surface phase transition between (2 × 4) and (4 × 2). - Highlights: • Discontinuous surface phase transition phenomena on the flat InAs(001) surface • Nanoscale InAs(001) surface observed by scanning tunneling microscopy • “Zig-Zag” chains of α2(2 × 4) reconstruction • Critical role in the surface phase transition between (2 × 4) and (4 × 2)

  17. Soliton analysis in complex molecular systems: A zig-zag chain

    International Nuclear Information System (INIS)

    Christiansen, P.L.; Savin, A.V.; Zolotaryuk, A.V.

    1997-01-01

    A simple numerical method for seeking solitary wave solutions of a permanent profile in molecular systems of big complexity is presented. The method is essentially based on the minimization of a finite-dimensional function which is chosen under an appropriate discretization of time derivatives in equations of motion. In the present paper, it is applied to a zig-zag chain backbone of coupled particles, each of which has two degrees of freedom (longitudinal and transverse). Both topological and nontopological soliton solutions are treated for this chain when it is (i) subjected to a two-dimensional periodic substrate potential or (ii) considered as an isolated object, respectively. In the first case, which may be considered as a zig-zag generalization of the Frenkel-Kontorova chain model, two types of kink solutions with different topological charges, describing vacancies of one or two atoms (I- or II-kinks) and defects with excess one or two atoms in the chain (I- or II-antikinks), have been found. The second case (isolated chain) is a generalization of the well-known Fermi-Pasta-Ulam chain model, which takes into account transverse degrees of freedom of the chain molecules. Two types of stable nontopological soliton solutions which describe either (i) a supersonic solitary wave of longitudinal stretching accompanied by transverse slandering or supersonic pulses of longitudinal compression propagating together with localized transverse thickening (bulge) have been obtained. 32 refs., 11 figs

  18. Studi Kinerja Solar Water Heater Dengan Aliran Zig-zag Beralur Balok

    OpenAIRE

    Ikhsan, M. Rizki; Soeparman, Sudjito; Sasongko, Mega Nur

    2017-01-01

    Solar energy can be used for water heating by using solar water heater application. Therefore, its still needs some modification due to its low efficiency. This modification can be done by replacing the conventional plate of solar collectors into a double plate with a zig-zag pattern. The results shown that along with the decreasing of water flow rates could significantly increase the useful energy (Qu). Initial temperature of water inlet could affect the generated maximum temperature. The hi...

  19. Reversible conformational transition gives rise to 'zig-zag' temperature dependence of the rate constant of irreversible thermoinactivation of enzymes.

    Science.gov (United States)

    Levitsky VYu; Melik-Nubarov, N S; Siksnis, V A; Grinberg VYa; Burova, T V; Levashov, A V; Mozhaev, V V

    1994-01-15

    We have obtained unusual 'zig-zag' temperature dependencies of the rate constant of irreversible thermoinactivation (k(in)) of enzymes (alpha-chymotrypsin, covalently modified alpha-chymotrypsin, and ribonuclease) in a plot of log k(in) versus reciprocal temperature (Arrhenius plot). These dependencies are characterized by the presence of both ascending and descending linear portions which have positive and negative values of the effective activation energy (Ea), respectively. A kinetic scheme has been suggested that fits best for a description of these zig-zag dependencies. A key element of this scheme is the temperature-dependent reversible conformational transition of enzyme from the 'low-temperature' native state to a 'high-temperature' denatured form; the latter form is significantly more stable against irreversible thermoinactivation than the native enzyme. A possible explanation for a difference in thermal stabilities is that low-temperature and high-temperature forms are inactivated according to different mechanisms. Existence of the suggested conformational transition was proved by the methods of fluorescence spectroscopy and differential scanning calorimetry. The values of delta H and delta S for this transition, determined from calorimetric experiments, are highly positive; this fact underlies a conclusion that this heat-induced transition is caused by an unfolding of the protein molecule. Surprisingly, in the unfolded high-temperature conformation, alpha-chymotrypsin has a pronounced proteolytic activity, although this activity is much smaller than that of the native enzyme.

  20. Communication: electronic band gaps of semiconducting zig-zag carbon nanotubes from many-body perturbation theory calculations.

    Science.gov (United States)

    Umari, P; Petrenko, O; Taioli, S; De Souza, M M

    2012-05-14

    Electronic band gaps for optically allowed transitions are calculated for a series of semiconducting single-walled zig-zag carbon nanotubes of increasing diameter within the many-body perturbation theory GW method. The dependence of the evaluated gaps with respect to tube diameters is then compared with those found from previous experimental data for optical gaps combined with theoretical estimations of exciton binding energies. We find that our GW gaps confirm the behavior inferred from experiment. The relationship between the electronic gap and the diameter extrapolated from the GW values is also in excellent agreement with a direct measurement recently performed through scanning tunneling spectroscopy.

  1. Cubic Zig-Zag Enrichment of the Classical Kirchhoff Kinematics for Laminated and Sandwich Plates

    Science.gov (United States)

    Nemeth, Michael P.

    2012-01-01

    A detailed anaylsis and examples are presented that show how to enrich the kinematics of classical Kirchhoff plate theory by appending them with a set of continuous piecewise-cubic functions. This analysis is used to obtain functions that contain the effects of laminate heterogeneity and asymmetry on the variations of the inplane displacements and transverse shearing stresses, for use with a {3, 0} plate theory in which these distributions are specified apriori. The functions used for the enrichment are based on the improved zig-zag plate theory presented recently by Tessler, Di Scuva, and Gherlone. With the approach presented herein, the inplane displacements are represented by a set of continuous piecewise-cubic functions, and the transverse shearing stresses and strains are represented by a set of piecewise-quadratic functions that are discontinuous at the ply interfaces.

  2. Analysis and evaluation of zig-zag slab laser amplifier with optical diamond geometry

    International Nuclear Information System (INIS)

    Matsumoto, Osamu; Yasuhara, Ryo; Kanabe, Tadashi

    2007-01-01

    In this paper, we describe the development of a high-average-power solid-state laser system and the derivation of equations for the amplification of a laser beam. This laser system is capable of generating an output energy of 10J per pulse at a wavelength of 1,053nm in a 10 Hz operation for scientific and industrial applications. The main amplifier of our system is a laser-diode-pumped solid-state amplifier. A water-cooled Nd:glass slab is pumped with two 803 nm AlGaAs laser-diode modules. The laser beam propagates through zig-zag optical paths four times and is amplified. To estimate laser output energy, we have derived and evaluated equations for the amplification of the laser beam, and designed and constructed a laser system based on the calculated results. Experimental results reveal an output energy of 10.6 J at 1 Hz, which closely fits the results calculated using the derived equations. (author)

  3. Pengaruh Latihan Lari Zig-Zag, Lari Bolak-Balik, Push-Up dengan Pola Circuit Training Terhadap Kesegaran Jasmani Siswa Ekstrakurikuler Sepak Bola SMAN I Soa Tahun Ajaran 2015/2016

    Directory of Open Access Journals (Sweden)

    Wiljiwianus Primus Wio Bei

    2017-11-01

    Full Text Available Tujuan penelitian ini adalah untuk mengetahui pengaruh latihan lari zig-zag,  lari bolak-balik, push-up dengan pola circuit training studi pada siswa ekstrakurikuler sepak bola SMAN 1 Soa. Penelitian ini adalah penelitian eksperimen dengan desain the static –group pretest – posttest design. Sampel penelitian ini sebanyak 40 orang terdiri atas 20 orang adalah kelompok eksperimen dan 20 orang kelompok kontrol yang diambil secara random. Untuk mengumpulkan data peningkatan Kesegaran Jasmani digunakan TKJI, kemudian data dianalisis dengan t-test. Hasil analisis menunjukan bahwa nilai thitung sebesar 3,5 lebih besar dari nilai ttabel 2,042 pada taraf signifikasi 5 % (α=0,05. Ini berarti ada perbedaan yang signifikan Kesegaran Jasmani antara kelompok eksperimen dan kelompok kontrol. Dengan demikian dapat disimpulkan bahwa latihan lari zig-zag, lari bolak-balik, push up dengan pola circuit training berpengaruh terhadap kesegaran jasmani pada siswa peserta ektrakurikuler sepak bola SMAN 1 Soa.

  4. Magnetic excitations in low-dimensional spin systems: neutron scattering study on AV2O5

    International Nuclear Information System (INIS)

    Nakajima, Kenji

    1997-01-01

    Recent experiments on vanadium oxide bronzes AV 2 O 5 (A=Na, Mg, Li) are reviewed. Experiments are carried out combining two triple-axis spectrometers installed at a thermal beam port and a cold neutron guide at JRR-3M. Spin-wave excitations in single crystals NaV 2 O 5 in the spin-Peierls state shows a steep intra-chain dispersion, which is consistent with estimated exchange interaction from magnetization measurement, and a weak inter-chain dispersion. In the low energy excitation measurement on powder sample of MgV 2 O 5 , we have observed energy gap of 2 meV, which indicates that this material is a ladder system with strong 1D character. Preliminary result on LiV 2 O 5 , which is expected to be a simple 1D antiferromagnet or a zig-zag chain, is also mentioned

  5. Modulational Instability and Quantum Discrete Breather States of Cold Bosonic Atoms in a Zig-Zag Optical Lattice

    Science.gov (United States)

    Chang, Xia; Xie, Jiayu; Wu, Tianle; Tang, Bing

    2018-07-01

    A theoretical study on modulational instability and quantum discrete breather states in a system of cold bosonic atoms in zig-zag optical lattices is presented in this work. The time-dependent Hartree approximation is employed to deal with the multiple body problem. By means of a linear stability analysis, we analytically study the modulational instability, and estimate existence conditions of the bright stationary localized solutions for different values of the second-neighbor hopping constant. On the other hand, we get analytical bright stationary localized solutions, and analyze the influence of the second-neighbor hopping on their existence conditions. The predictions of the modulational instability analysis are shown to be reliable. Using these stationary localized single-boson wave functions, the quantum breather states corresponding to the system with different types of nonlinearities are constructed.

  6. Modulational Instability and Quantum Discrete Breather States of Cold Bosonic Atoms in a Zig-Zag Optical Lattice

    Science.gov (United States)

    Chang, Xia; Xie, Jiayu; Wu, Tianle; Tang, Bing

    2018-04-01

    A theoretical study on modulational instability and quantum discrete breather states in a system of cold bosonic atoms in zig-zag optical lattices is presented in this work. The time-dependent Hartree approximation is employed to deal with the multiple body problem. By means of a linear stability analysis, we analytically study the modulational instability, and estimate existence conditions of the bright stationary localized solutions for different values of the second-neighbor hopping constant. On the other hand, we get analytical bright stationary localized solutions, and analyze the influence of the second-neighbor hopping on their existence conditions. The predictions of the modulational instability analysis are shown to be reliable. Using these stationary localized single-boson wave functions, the quantum breather states corresponding to the system with different types of nonlinearities are constructed.

  7. The rich variety of cuprates

    International Nuclear Information System (INIS)

    Rice, T.M.

    1997-01-01

    The discovery of high-T c superconductivity focussed attention on the cuprates. Square planar coordinated Cu 2+ -ions are ideal S=1/2 ions. The exchange interaction between neighboring ions is very different for edge sharing (weak and ferromagnetic) and corner sharing (strong and antiferromagnetic) configurations. Many different magnetic structures are possible, e.g. chains, zig-zag chains, ladders, etc., weakly coupled to each other. The spin-liquid state of the two-leg ladder is especially interesting, not least because of the possible quantum critical point separating the spin liquid and long-range ordered states as the interladder coupling is increased. Hole doping to introduce mobile Cu 3+ -ionic configuration opens new possibilities. The recent discovery of superconductivity under pressure in a doped ladder system is encouraging. (orig.)

  8. Excitation spectrum of Heisenberg spin ladders

    International Nuclear Information System (INIS)

    Barnes, T.; Dagotto, E.; Riera, J.; Swanson, E.S.

    1993-01-01

    Heisenberg antiferromagnetic spin ''ladders'' (two coupled spin chains) are low-dimensional magnetic systems which for S=1/2 interpolate between half-integer-spin chains, when the chains are decoupled, and effective integer-spin one-dimensional chains in the strong-coupling limit. The spin-1/2 ladder may be realized in nature by vanadyl pyrophosphate, (VO) 2 P 2 O 7 . In this paper we apply strong-coupling perturbation theory, spin-wave theory, Lanczos techniques, and a Monte Carlo method to determine the ground-state energy and the low-lying excitation spectrum of the ladder. We find evidence of a nonzero spin gap for all interchain couplings J perpendicular >0. A band of spin-triplet excitations above the gap is also analyzed. These excitations are unusual for an antiferromagnet, since their long-wavelength dispersion relation behaves as (k-k 0 ) 2 (in the strong-coupling limit J perpendicular much-gt J, where J is the in-chain antiferromagnetic coupling). Their band is folded, with a minimum energy at k 0 =π, and a maximum between k 1 =π/2 (for J perpendicular =0) and 0 (for J perpendicular =∞). We also give numerical results for the dynamical structure factor S(q,ω), which can be determined in neutron scattering experiments. Finally, possible experimental techniques for studying the excitation spectrum are discussed

  9. Ladder Ising spin configurations. Pt. 1. Heat capacity

    International Nuclear Information System (INIS)

    Mejdani, R.; Lambros, A.

    1996-01-01

    We consider a ladder Ising spin model (with two coupled Ising spin chains), characterized by two couplings (interchain and intrachain couplings), to study in detail, in an analytical way, its thermal behaviour and particularly the variation of the specific heat versus temperature, the ratio of interaction constants, and the magnetic field. It is interesting that when the competition between interchain and intrachain interactions is strong the specific heat exhibits a double peak and when the competition is not so strong the specific heat has a single peak. Further, without entering into details, we give, in a numerical way, some similar results for more complicated ladder configurations (with more than two linear Ising chains). The spin-1/2 ladders or systems of spin chains may be realized in nature by vanadyl pyrophosphate ((VO) 2 P 2 O 7 ) or similar materials. All these intermediate systems are today important to gain further insight into the physics of one-dimensional spin chains and two-dimensional high-T c spin systems, both of which have shown interesting and unusual magnetic and superconducting properties. It is plausible that experimental and theoretical studies of ladders may lead to other interesting physical phenomena. (orig.)

  10. Thermal analysis of smart composite laminated angle-ply using higher order shear deformation theory with zig zag function

    Science.gov (United States)

    YagnaSri, P.; Siddiqui, Maimuna; Vijaya Nirmala, M.

    2018-03-01

    The objective of the work is to develop the higher order theory for piezoelectric composite laminated plates with zigzag function and to determine the thermal characteristics of piezoelectric laminated plate with zig zag function for different aspect ratios (a/h), thickness ratios (z/h) and voltage and also to evaluate electric potential function by solving second order differential equation satisfying electric boundary conditions along the thickness direction of piezoelectric layer. The related functions and derivations for equation of motion are obtained using the dynamic version of the principle of virtual work or Hamilton’s principle. The solutions are obtained by using Navier’s stokes method for anti-symmetric angle-ply with specific type of simply supported boundary conditions. Computer programs have been developed for realistic prediction of stresses and deflections for various sides to thickness ratios (a/h) and voltages.

  11. Doped spin ladders under magnetic field

    International Nuclear Information System (INIS)

    Roux, G.

    2007-07-01

    This thesis deals with the physics of doped two-leg ladders which are a quasi one-dimensional and unconventional superconductor. We particularly focus on the properties under magnetic field. Models for strongly correlated electrons on ladders are studied using exact diagonalization and density-matrix renormalization group (DMRG). Results are also enlightened by using the bosonization technique. Taking into account a ring exchange it highlights the relation between the pairing of holes and the spin gap. Its influence on the dynamics of the magnetic fluctuations is also tackled. Afterwards, these excitations are probed by the magnetic field by coupling it to the spin degree of freedom of the electrons through Zeeman effect. We show the existence of doping-dependent magnetization plateaus and also the presence of an inhomogeneous superconducting phase (FFLO phase) associated with an exceeding of the Pauli limit. When a flux passes through the ladder, the magnetic field couples to the charge degree of freedom of the electrons via orbital effect. The diamagnetic response of the doped ladder probes the commensurate phases of the t-J model at low J/t. Algebraic transverse current fluctuations are also found once the field is turned on. Lastly, we report numerical evidences of a molecular superfluid phase in the 3/2-spin attractive Hubbard model: at a density low enough, bound states of four fermions, called quartets, acquire dominant superfluid fluctuations. The observed competition between the superfluid and density fluctuations is connected to the physics of doped ladders. (author)

  12. Nested Bethe Ansatz for Spin Ladder Model with Open Boundary Conditions

    International Nuclear Information System (INIS)

    Wu Junfang; Zhang Chunmin; Yue Ruihong; Li Runling

    2005-01-01

    The nested Bethe ansatz (BA) method is applied to find the eigenvalues and the eigenvectors of the transfer matrix for spin-ladder model with open boundary conditions. Based on the reflection equation, we find the general diagonal solution, which determines the general boundary interaction in the Hamiltonian. We introduce the spin-ladder model with open boundary conditions. By finding the solution K ± of the reflection equation which determines the nontrivial boundary terms in the Hamiltonian, we diagonalize the transfer matrix of the spin-ladder model with open boundary conditions in the framework of nested BA.

  13. Doped spin ladders under magnetic field; Echelles de spins dopees sous champ magnetique

    Energy Technology Data Exchange (ETDEWEB)

    Roux, G

    2007-07-15

    This thesis deals with the physics of doped two-leg ladders which are a quasi one-dimensional and unconventional superconductor. We particularly focus on the properties under magnetic field. Models for strongly correlated electrons on ladders are studied using exact diagonalization and density-matrix renormalization group (DMRG). Results are also enlightened by using the bosonization technique. Taking into account a ring exchange it highlights the relation between the pairing of holes and the spin gap. Its influence on the dynamics of the magnetic fluctuations is also tackled. Afterwards, these excitations are probed by the magnetic field by coupling it to the spin degree of freedom of the electrons through Zeeman effect. We show the existence of doping-dependent magnetization plateaus and also the presence of an inhomogeneous superconducting phase (FFLO phase) associated with an exceeding of the Pauli limit. When a flux passes through the ladder, the magnetic field couples to the charge degree of freedom of the electrons via orbital effect. The diamagnetic response of the doped ladder probes the commensurate phases of the t-J model at low J/t. Algebraic transverse current fluctuations are also found once the field is turned on. Lastly, we report numerical evidences of a molecular superfluid phase in the 3/2-spin attractive Hubbard model: at a density low enough, bound states of four fermions, called quartets, acquire dominant superfluid fluctuations. The observed competition between the superfluid and density fluctuations is connected to the physics of doped ladders. (author)

  14. Spin ordering in three-leg ladders in Ludwigite systems

    International Nuclear Information System (INIS)

    Vallejo, E.; Avignon, M.

    2007-01-01

    We study the spin ordering in a three-leg ladder present in Ludwigite systems formed of localized spins interacting with an extra electron per rung. We also consider the competition with super exchange interactions resulting in a very rich phase diagram. Among the phases we find the possibility of ferromagnetic rungs ordered antiferromagnetically and a zigzag spin ordering linked to the formation of a charge ordering as observed

  15. Quantum entanglement and thermal reduced density matrices in fermion and spin systems on ladders

    International Nuclear Information System (INIS)

    Chen, Xiao; Fradkin, Eduardo

    2013-01-01

    Numerical studies of the reduced density matrix of a gapped spin-1/2 Heisenberg antiferromagnet on a two-leg ladder find that it has the same form as the Gibbs density matrix of a gapless spin-1/2 Heisenberg antiferromagnetic chain at a finite temperature determined by the spin gap of the ladder. We investigate this interesting result by considering a model of free fermions on a two-leg ladder (gapped by the inter-chain tunneling operator) and in spin systems on a ladder with a gapped ground state using exact solutions and several controlled approximations. We calculate the reduced density matrix and the entanglement entropy for a leg of the ladder (i.e. a cut made between the chains). In the fermionic system we find the exact form of the reduced density matrix for one of the chains and determine the entanglement spectrum explicitly. Here we find that in the weak tunneling limit of the ladder the entanglement entropy of one chain of the gapped ladder has a simple and universal form dictated by conformal invariance. In the case of the spin system, we consider the strong coupling limit by using perturbation theory and get the reduced density matrix by the Schmidt decomposition. The entanglement entropies of a general gapped system of two coupled conformal field theories (in 1 + 1 dimensions) are discussed using the replica trick and scaling arguments. We show that (1) for a system with a bulk gap the reduced density matrix has the form of a thermal density matrix, (2) the long-wavelength modes of one subsystem (a chain) of a gapped coupled system are always thermal, (3) the von Neumann entropy equals the thermodynamic entropy of one chain, and (4) the bulk gap plays the role of effective temperature. (paper)

  16. Ladder physics in the spin fermion model

    Science.gov (United States)

    Tsvelik, A. M.

    2017-05-01

    A link is established between the spin fermion (SF) model of the cuprates and the approach based on the analogy between the physics of doped Mott insulators in two dimensions and the physics of fermionic ladders. This enables one to use nonperturbative results derived for fermionic ladders to move beyond the large-N approximation in the SF model. It is shown that the paramagnon exchange postulated in the SF model has exactly the right form to facilitate the emergence of the fully gapped d -Mott state in the region of the Brillouin zone at the hot spots of the Fermi surface. Hence, the SF model provides an adequate description of the pseudogap.

  17. Ladder physics in the spin fermion model

    International Nuclear Information System (INIS)

    Tsvelik, A. M.

    2017-01-01

    A link is established between the spin fermion (SF) model of the cuprates and the approach based on the analogy between the physics of doped Mott insulators in two dimensions and the physics of fermionic ladders. This enables one to use nonperturbative results derived for fermionic ladders to move beyond the large-N approximation in the SF model. Here, it is shown that the paramagnon exchange postulated in the SF model has exactly the right form to facilitate the emergence of the fully gapped d-Mott state in the region of the Brillouin zone at the hot spots of the Fermi surface. Hence, the SF model provides an adequate description of the pseudogap.

  18. Experimental essay and numerical modelling in a reduced model with physical similarity to a pipeline with zig-zag geometry in Guanabara Bay (PE-3); Ensaio experimental e modelagem numerica em modelo reduzido com semelhanca fisica do duto com geometria zig-zag da Baia de Guanabara (PE-3)

    Energy Technology Data Exchange (ETDEWEB)

    Poiate, Junior, Edgard; Costa, Alvaro M. da; Amaral, Claudio S; Rocha, Renato S [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES); Guimaraes, Giuseppe B; Souza, Pablo F [Pontificia Univ. Catolica do Rio de Janeiro, RJ (Brazil)

    2003-07-01

    In January 2000 PETROBRAS faced a leakage of heavy heated MF380 oil from a 16'' pipeline in Guanabara Bay. The thermal structural buckling of the pipeline, interacting with the soil, induced the rupture of the pipeline wall, causing the leakage of oil. In order to overcome this undesired phenomenon PETROBRAS studied several alternatives of a new pipeline. As a result of these studies a pipeline with 'ZIGZAG' geometry was adopted, named PE-3. Due to the very few applications of this kind of concept by the oil industry and in different soil conditions compared to the existing one in Guanabara Bay, a very sophisticated procedure including the simulation of the thermal mechanical interactions between the soil and the pipeline structure was developed. Computer modeling was carried out using the finite element method considering the soil and pipeline non-linear material behavior and finite displacements. In order to validate the numerical modelling was build an experimental test in a reduced model with physics similarity of a pipeline with ZIG-ZAG geometry (PE-3). The numerical and experimental results are comparing and have a good agreement. (author)

  19. Direct observation of magnon fractionalization in the quantum spin ladder

    NARCIS (Netherlands)

    Thielemann, B.; Rüegg, C.; Rønnow, H.M.; Läuchli, A.M.; Caux, J.S.; Normand, B.; Biner, D.; Krämer, K.W.; Güdel, H.U.; Stahn, J.; Habicht, K.; Kiefer, K.; Boehm, M.; McMorrow, D.F.; Mesot, J.

    2009-01-01

    We measure by inelastic neutron scattering the spin excitation spectra as a function of applied magnetic field in the quantum spin-ladder material (C5H12N)2CuBr4. Discrete magnon modes at low fields in the quantum disordered phase and at high fields in the saturated phase contrast sharply with a

  20. Phase transitions and thermal entanglement of the distorted Ising-Heisenberg spin chain: topology of multiple-spin exchange interactions in spin ladders

    Science.gov (United States)

    Arian Zad, Hamid; Ananikian, Nerses

    2017-11-01

    We consider a symmetric spin-1/2 Ising-XXZ double sawtooth spin ladder obtained from distorting a spin chain, with the XXZ interaction between the interstitial Heisenberg dimers (which are connected to the spins based on the legs via an Ising-type interaction), the Ising coupling between nearest-neighbor spins of the legs and rungs spins, respectively, and additional cyclic four-spin exchange (ring exchange) in the square plaquette of each block. The presented analysis supplemented by results of the exact solution of the model with infinite periodic boundary implies a rich ground state phase diagram. As well as the quantum phase transitions, the characteristics of some of the thermodynamic parameters such as heat capacity, magnetization and magnetic susceptibility are investigated. We prove here that among the considered thermodynamic and thermal parameters, solely heat capacity is sensitive versus the changes of the cyclic four-spin exchange interaction. By using the heat capacity function, we obtain a singularity relation between the cyclic four-spin exchange interaction and the exchange coupling between pair spins on each rung of the spin ladder. All thermal and thermodynamic quantities under consideration should be investigated by regarding those points which satisfy the singularity relation. The thermal entanglement within the Heisenberg spin dimers is investigated by using the concurrence, which is calculated from a relevant reduced density operator in the thermodynamic limit.

  1. Electron spin resonance modes in a strong-leg ladder in the Tomonaga-Luttinger liquid phase

    Science.gov (United States)

    Ozerov, M.; Maksymenko, M.; Wosnitza, J.; Honecker, A.; Landee, C. P.; Turnbull, M. M.; Furuya, S. C.; Giamarchi, T.; Zvyagin, S. A.

    2015-12-01

    Magnetic excitations in the strong-leg quantum spin ladder compound (C7H10N) 2CuBr4 (known as DIMPY) in the field-induced Tomonaga-Luttinger spin-liquid phase are studied by means of high-field electron spin resonance (ESR) spectroscopy. The presence of a gapped ESR mode with unusual nonlinear frequency-field dependence is revealed experimentally. Using a combination of analytic and exact-diagonalization methods, we compute the dynamical structure factor and identify this mode with longitudinal excitations in the antisymmetric channel. We argue that these excitations constitute a fingerprint of the spin dynamics in a strong-leg spin-1/2 Heisenberg antiferromagnetic ladder and owe their ESR observability to the uniform Dzyaloshinskii-Moriya interaction.

  2. Bound states in weakly disordered spin ladders

    Energy Technology Data Exchange (ETDEWEB)

    Arlego, M. [Departamento de Fisica, Universidad Nacional de La Plata, CC 67 (1900) La Plata (Argentina)]. E-mail: arlego@venus.fisica.unlp.edu.ar; Brenig, W. [Institut fuer Theoretische Physik, Technische Universitaet Braunschweig (Germany); Cabra, D.C. [Laboratoire de Physique Theorique, Universite Louis Pasteur Strasbourg (France); Heidrich-Meisner, F. [Institut fuer Theoretische Physik, Technische Universitaet Braunschweig (Germany); Honecker, A. [Institut fuer Theoretische Physik, Technische Universitaet Braunschweig (Germany); Rossini, G. [Departamento de Fisica, Universidad Nacional de La Plata, CC 67 (1900) La Plata (Argentina)

    2005-04-30

    We study the appearance of bound states in the spin gap of spin-12 ladders induced by weak bond disorder. Starting from the strong-coupling limit, i.e., the limit of weakly coupled dimers, we perform a projection on the single-triplet subspace and derive the position of bound states for the single impurity problem of one modified coupling as well as for small impurity clusters. The case of a finite concentration of impurities is treated with the coherent-potential approximation (CPA) in the strong-coupling limit and compared with numerical results. Further, we analyze the details in the structure of the density of states and relate their origin to the influence of impurity clusters.

  3. Magnetic properties and phase transitions in LiCu_2O2 by ^7Li NMR

    Science.gov (United States)

    Caldwell, Tod; Moulton, William G.; Reyes, Arneil P.; Kuhns, Phillip L.; Cao, Gang; Xin, Yiu; Crow, Jack E.

    2001-03-01

    LiCu_2O2 is a compound with double chain Cu^2+ copper ions separated in pairs by Li and Cu^1+ that forms a spin ladder or zig-zag chain system depending on the relative J's. The orthorhombic single crystals are highly twinned as determined by TEM. Magnetization and specific heat show ladder behavior above a transition near 25 K, suggestive of a first order transition from specific heat data. ^7Li NMR spectra show a 0.16%,(c-axis)nearly temperature independent shift above the transition, and is nearly an order of magnitude smaller perpendicular, with a dramatic increase at 24.3 K. At 24.3 the spectrum broadens and splits into 6 (not fully resolved) lines, maximum splitting 0.2 T, clearly indicating the presence of a static internal field due to some AF spin arrangement. The splitting is temperature independent below 23 K, unusual for an AF.The large shift of the spectrum center below the transition may indicate large spin fluctuations. No evidence of a second transition at 9 K observed in the specific heat and magnetization are found in the NMR data. The results for the quadrupole parameters and the possible spin configurations will be presented.

  4. Phase transitions and magnetization of the mixed-spin Ising–Heisenberg double sawtooth frustrated ladder

    Science.gov (United States)

    Arian Zad, Hamid; Ananikian, Nerses

    2018-04-01

    The mixed spin-(1,1/2) Ising–Heisenberg double sawtooth ladder containing a mixture of both spin-1 and spin-1/2 nodal atoms, and the spin-1/2 interstitial dimers are approximately solved by the transfer-matrix method. Here, we study in detail the ground-state phase diagrams, also influences of the bilinear exchange coupling on the rungs and cyclic four-spin exchange interaction in square plaquette of each block on the magnetization and magnetic susceptibility of the suggested ladder at low temperature. Such a double sawtooth ladder may be found in a Shastry-Sutherland lattice-type. In spite of the spin ordering of odd and even blocks being different from each other, due to the commutation relation between all different block Hamiltonians, phase diagrams, magnetization behavior and thermodynamic properties of the model are the same for odd and even blocks. We show that at low temperature, both exchange couplings can change the quality and quantity of the magnetization plateaus versus the magnetic field changes. Specially, we find a new magnetization plateau M/Ms= 5/6 for this model. Besides, we examine the magnetic susceptibility and specific heat of the model in detail. It is proven that behaviors of the magnetization and the magnetic susceptibility coincide at low temperature. The specific heat displays diverse temperature dependencies, which include a Schottky-type peak at a special temperature interval. We observe that with increase of the bilinear exchange coupling on the rungs, second peak temperature dependence grows.

  5. Groundstate fidelity phase diagram of the fully anisotropic two-leg spin-½ XXZ ladder

    Science.gov (United States)

    Li, Sheng-Hao; Shi, Qian-Qian; Batchelor, Murray T.; Zhou, Huan-Qiang

    2017-11-01

    The fully anisotropic two-leg spin-\\tfrac{1}{2} XXZ ladder model is studied in terms of an algorithm based on the tensor network (TN) representation of quantum many-body states as an adaptation of projected entangled pair states to the geometry of translationally invariant infinite-size quantum spin ladders. The TN algorithm provides an effective method to generate the groundstate wave function, which allows computation of the groundstate fidelity per lattice site, a universal marker to detect phase transitions in quantum many-body systems. The groundstate fidelity is used in conjunction with local order and string order parameters to systematically map out the groundstate phase diagram of the ladder model. The phase diagram exhibits a rich diversity of quantum phases. These are the ferromagnetic, stripe ferromagnetic, rung singlet, rung triplet, Néel, stripe Néel and Haldane phases, along with the two XY phases XY1 and XY2.

  6. Comments about the use of a Zig-Zag transformer to reduce the neutral current created by unbalanced nonlinear loads

    International Nuclear Information System (INIS)

    Beverly, L.; Hance, R.; Kristalinski, A.; Visser, A.

    1993-09-01

    The subject of AC line currents with high harmonic content and the potential for overloaded neutral wires caused by the non-linear loading of electronic power supplies has become one of the most popular and at the same time a very complex topic among electrical engineers. Different solutions are offered for this problem. Some examples are specially designed K-rated AC distribution transformers, delta connected primary windings, and L-C tuned filters. All of the above methods have some limitations. For instance, a K-rated transformer does not eliminate harmonics, but transmits them into the feeder. Neutral currents that flow from various loads to the K-rated transformer are still very high. These K-rated transformers are more expensive and are larger in physical size than conventional transformers. The delta connected primary of a power distribution transformer can only eliminate triplen harmonics for balanced loads. Neutral currents caused by the loads are not eliminated. The primary side circuit breaker may also not protect a transformer against overcurrents because the circuit breaker will not see the triplen harmonic current that is circulating in the primary of the transformer. L-C filters can create undesirable resonances, which will lead to an increase in harmonic currents. Another solution is to use a number of small Zig-Zag transformers to reduce the neutral current. This is attractive for the following reasons: relatively low cost, simplicity, ease of installation on existing distribution systems, ability to keep neutral currents local thus eliminating the need for larger neutral wires, and the ability to improve the fundamental load current balance as well

  7. Analytical recursive method to ascertain multisite entanglement in doped quantum spin ladders

    Science.gov (United States)

    Roy, Sudipto Singha; Dhar, Himadri Shekhar; Rakshit, Debraj; SenDe, Aditi; Sen, Ujjwal

    2017-08-01

    We formulate an analytical recursive method to generate the wave function of doped short-range resonating valence bond (RVB) states as a tool to efficiently estimate multisite entanglement as well as other physical quantities in doped quantum spin ladders. We prove that doped RVB ladder states are always genuine multipartite entangled. Importantly, our results show that within specific doping concentration and model parameter regimes, the doped RVB state essentially characterizes the trends of genuine multiparty entanglement in the exact ground states of the Hubbard model with large on-site interactions, in the limit that yields the t -J Hamiltonian.

  8. Magnetic phase diagram of a frustrated spin ladder

    Science.gov (United States)

    Sugimoto, Takanori; Mori, Michiyasu; Tohyama, Takami; Maekawa, Sadamichi

    2018-04-01

    Frustrated spin ladders show magnetization plateaux depending on the rung-exchange interaction and frustration defined by the ratio of first and second neighbor exchange interactions in each chain. This paper reports on its magnetic phase diagram. Using the variational matrix-product state method, we accurately determine phase boundaries. Several kinds of magnetization plateaux are induced by the frustration and the strong correlation among quasiparticles on a lattice. The appropriate description of quasiparticles and their relevant interactions are changed by a magnetic field. We find that the frustration differentiates the triplet quasiparticle from the singlet one in kinetic energy.

  9. Field dependence of magnetic order and excitations in the Kitaev candidate alpha-RuCl3

    Science.gov (United States)

    Banerjee, Arnab; Kelley, Paula; Winn, Barry; Aczel, Adam; Lumsden, Mark; Mandrus, David; Nagler, Stephen

    The search for new quantum states of matter has been one of the forefront endeavors of condensed matter physics. The two-dimensional Kitaev quantum spin liquid (QSL) is of special interest as an exactly solvable spin-liquid model exhibiting exotic fractionalized excitations. Recently, alpha-RuCl3 has been identified as a candidate system for exhibiting some aspects of Kitaev QSL physics. The spins in this material exhibit zig-zag order at low temperatures, and show both low energy spin wave excitation arising from the ordered state as well as a continuum excitation extending to higher energies that has been taken as evidence for QSL relate Majorana fermions. In this talk, we show that the application of an in-plane magnetic field suppresses the zig-zag order possibly resulting in a state devoid of long-range order. Field-dependent inelastic neutron scattering on single-crystal shows a remarkable effect on the excitation spectrum above the critical field. The work is supported by US-DOE, Office of Science, Basic Energy Sciences and User Facilities Divisions, and also the Gordon and Betty Moore Foundation EPiQS Grant GBFM4416.

  10. Field-controlled magnetic order in the quantum spin-ladder system (Hpip)2CuBr4

    DEFF Research Database (Denmark)

    Thielemann, B.; Rüegg, C.; Kiefer, K.

    2009-01-01

    Neutron diffraction is used to investigate the field-induced, antiferromagnetically ordered state in the two-leg spin-ladder material (Hpip)(2)CuBr4. This "classical" phase, a consequence of weak interladder coupling, is nevertheless highly unconventional: its properties are influenced strongly...

  11. Fulltext PDF

    Indian Academy of Sciences (India)

    IAS Admin

    Classroom. Solution of Cubic Equations: An Alternative Method. T R Mukundan. Interconversion of Fischer and Zig-Zag Projections. Learning Stereochemistry with the Help of Hands. Syed R Hussaini. Motion of a Tiny Tool Thrown by an Astronaut towards another Astronaut inside a Spinning Space. Vehicle in a State of ...

  12. Quantum phase transitions in effective spin-ladder models for graphene zigzag nanoribbons

    Science.gov (United States)

    Koop, Cornelie; Wessel, Stefan

    2017-10-01

    We examine the magnetic correlations in quantum spin models that were derived recently as effective low-energy theories for electronic correlation effects on the edge states of graphene nanoribbons. For this purpose, we employ quantum Monte Carlo simulations to access the large-distance properties, accounting for quantum fluctuations beyond mean-field-theory approaches to edge magnetism. For certain chiral nanoribbons, antiferromagnetic interedge couplings were previously found to induce a gapped quantum disordered ground state of the effective spin model. We find that the extended nature of the intraedge couplings in the effective spin model for zigzag nanoribbons leads to a quantum phase transition at a large, finite value of the interedge coupling. This quantum critical point separates the quantum disordered region from a gapless phase of stable edge magnetism at weak intraedge coupling, which includes the ground states of spin-ladder models for wide zigzag nanoribbons. To study the quantum critical behavior, the effective spin model can be related to a model of two antiferromagnetically coupled Haldane-Shastry spin-half chains with long-ranged ferromagnetic intrachain couplings. The results for the critical exponents are compared also to several recent renormalization-group calculations for related long-ranged interacting quantum systems.

  13. Low Energy Spectrum of Proximate Kitaev Spin Liquid α -RuCl3 by Terahertz Spectroscopy

    Science.gov (United States)

    Little, Arielle; Wu, Liang; Kelley, Paige; Banerjee, Arnab; Bridges, Craig; Yan, Jiaqiang; Nagler, Stephen; Mandrus, David; Orenstein, Joseph

    A Quantum Spin Liquid (QSL) is an ultra-quantum state of matter with no ordered ground state. Recently, a route to a QSL identified by Kitaev has received a great deal of attention. The compound α -RuCl3, in which Ru atoms form a honeycomb lattice, has been shown to possess Kitaev exchange interactions, although a smaller Heisenberg interaction exists and leads to a zig-zag antiferromagnetic state below 7 K. Because of proximity to the exactly-solvable Kitaev spin-liquid model, this material is considered a potential host for Majorana-like modes. In this work, we use time-domain terahertz (THz) Spectroscopy to probe the low-energy excitations of α -RuCl3. We observe the emergence of a sharp magnetic spin-wave absorption peak below the AFM ordering temperature at 7 K on top of a broad continuum that persists up to room temperature. Additionally we report the polarization dependence of the THz absorption, which reveals optical birefringence, indicating the presence of large monoclinic domains.

  14. Resonance – Journal of Science Education | News

    Indian Academy of Sciences (India)

    Interconversion of Fischer and Zig-Zag Projections - Learning Stereochemistry with the Help of Hands · Syed R Hussaini · More Details Fulltext PDF. pp 355-362 Classroom. Motion of a Tiny Tool Thrown by an Astronaut towards another Astronaut inside a Spinning Space Vehicle in a State of Free Fall Revisited · S N Maitra.

  15. Study of CP(N-1) theta-vacua by cluster simulation of SU(N) quantum spin ladders.

    Science.gov (United States)

    Beard, B B; Pepe, M; Riederer, S; Wiese, U-J

    2005-01-14

    D-theory provides an alternative lattice regularization of the 2D CP(N-1) quantum field theory in which continuous classical fields emerge from the dimensional reduction of discrete SU(N) quantum spins. Spin ladders consisting of n transversely coupled spin chains lead to a CP(N-1) model with a vacuum angle theta=npi. In D-theory no sign problem arises and an efficient cluster algorithm is used to investigate theta-vacuum effects. At theta=pi there is a first order phase transition with spontaneous breaking of charge conjugation symmetry for CP(N-1) models with N>2.

  16. Interplay between spin frustration and magnetism in the exactly solved two-leg mixed spin ladder

    Science.gov (United States)

    Qi, Yan; Lv, Song-Wei; Du, An; Yu, Nai-sen

    2016-11-01

    We study a mixed spin-(3/2, 1) ladder system with antiferromagnetic rung coupling and next-nearest-neighbor interaction. The exactly solved Ising-chain model is employed to investigate the ground-state properties and thermodynamics of the low-dimensional ladder system. Our results show that the competition between different exchange couplings brings in a large variety of ground states characterized by various values of normalized magnetization equal to 0, 1/5, 2/5, 3/5, 1. Moreover, an interesting double-peak structure is also detected in the thermal dependence of magnetic susceptibility and specific heat when the frustration comes into play. It is shown that the double-peak phenomenon at zero-field for the case of AF2 ground-state arises from the very strong antiferromagnetic rung coupling, while other cases are attributed to the excitations induced by temperature and external field around the phase boundary. Project supported by the National Natural Science Foundation of China (Grant No. 11547236), the General Project of the Education Department of Liaoning Province, China (Grant No. L2015130), the Fundamental Research Funds for the Central Universities, China (Grant Nos. DC201501065 and DCPY2016014), and the Doctoral Starting-up Foundation of Dalian Nationalities University, China.

  17. ZigBee-2007 Security Essentials

    DEFF Research Database (Denmark)

    Yuksel, Ender; Nielson, Hanne Riis; Nielson, Flemming

    2008-01-01

    ZigBee is a fairly new but promising standard for wireless networks due to its low resource requirements. As in other wireless network standards, security is an important issue and each new version of the ZigBee Specification enhances the level of the ZigBee security. In this paper, we present...... the security essentials of the latest ZigBee Specification, ZigBee-2007. We explain the key concepts, protocols, and computations. In addition, we formulate the protocols using standard protocol narrations. Finally, we identify the key challenges to be considered for consolidating ZigBee....

  18. Performance assessment and development of a design support tool for innovative BIPV façade systems

    NARCIS (Netherlands)

    Ghasempourabadi, M.

    2017-01-01

    This PDEng project is related to the development of two types of building-integrated photovoltaic (BIPV) façade systems: SoloWall and ZigZagSolar. SoloWall is a modular type of BIPV for integration in vertical facades, developed by SCX Solar. ZigZagSolar, developed by Wallvision, uses a series of

  19. Neutron scattering and μSR investigations of quasi-one-dimensional magnetism in the spin =3/2 compound Li3RuO4

    DEFF Research Database (Denmark)

    Manuel, P.; Adroja, D. T.; Lindgård, Per-Anker

    2011-01-01

    The S = 3/2, quasi-one-dimensional (1D) zig-zag chain Heisenberg antiferromagnet Li3RuO4 has been investigated using heat capacity, inelastic neutron scattering, neutron diffraction, and μSR measurements on a powder sample. Our neutron diffraction and μSR studies confirm a long-range ordering of ...

  20. Magnetic dimerization in the frustrated spin ladder Li2Cu2O (SO4)2

    Science.gov (United States)

    Vaccarelli, O.; Rousse, G.; Saúl, A.; Radtke, G.

    2017-11-01

    The magnetic properties of Li2Cu2O (SO4)2 are investigated in the framework of density functional theory. In its high-temperature tetragonal structure, this compound appears as a rare material realization of a frustrated spin-1/2 two-leg ladder, where magnetic frustration arises from competing nearest and next-nearest interactions along the legs. Through a large magnetoelastic coupling, the triclinic distortion occurring around 125 K is shown to induce the formation of a staggered dimer structure, lifting most of the magnetic frustration.

  1. Superconductivity in doped two-leg ladder cuprates

    International Nuclear Information System (INIS)

    Qin Jihong; Yuan Feng; Feng Shiping

    2006-01-01

    Within the t-J ladder model, superconductivity with a modified d-wave symmetry in doped two-leg ladder cuprates is investigated based on the kinetic energy driven superconducting mechanism. It is shown that the spin-liquid ground-state at the half-filling evolves into the superconducting ground-state upon doping. In analogy to the doping dependence of the superconducting transition temperature in the planar cuprate superconductors, the superconducting transition temperature in doped two-leg ladder cuprates increases with increasing doping in the underdoped regime, and reaches a maximum in the optimal doping, then decreases in the overdoped regime

  2. ZigBee test framework

    NARCIS (Netherlands)

    Bui Tat Minh, B.

    2015-01-01

    This project aims to build up a common ZigBee test framework. The common test framework can be used by teams developing devices using ZigBee. The objective is to reuse of the test infrastructure, test xtures as well as to simplify the exchange of test engineers between teams. In this project, we

  3. Magnetic susceptibilities of integrable quantum ladders

    International Nuclear Information System (INIS)

    Park, Soo A; Lee, K.

    2001-01-01

    As an extension of previous studies, we consider the magnetic susceptibilities of a coupled spin chain model at low temperature and of a more realistic model at low temperature and of a more realistic model having a t-J ladder structure at zero temperature. The magnetic susceptibilities for both models are obtained numerically when the coupling constant is greater than its critical value. In this region, the ladders behave as a single chain for H c and as two independent chains for H>H c , showing a divergence at H c . This divergence is expected to smear out at a finite temperature

  4. Characterization of the imprinting and expression patterns of ZAG2 in maize endosperm and embryo

    Directory of Open Access Journals (Sweden)

    Chaoxian Liu

    2015-02-01

    Full Text Available ZAG2 has been identified as a maternally expressed imprinted gene in maize endosperm. Our study revealed that paternally inherited ZAG2 alleles were imprinted in maize endosperm and embryo at 14 days after pollination (DAP, and consistently imprinted in endosperm at 10, 12, 16, 18, 20, 22, 24, 26, and 28 DAP in reciprocal crosses between B73 and Mo17. ZAG2 alleles were also imprinted in reciprocal crosses between Zheng 58 and Chang 7-2 and between Huang C and 178. ZAG2 alleles exhibited differential imprinting in hybrids of 178 × Huang C and B73 × Mo17, while in other hybrids ZAG2 alleles exhibited binary imprinting. The tissue-specific expression pattern of ZAG2 showed that ZAG2 was expressed at a high level in immature ears, suggesting that ZAG2 plays important roles in not only kernel but ear development.

  5. Disorder effects in the S=1 antiferromagnetic spin ladder CaV{sub 2}O{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Guitarra, S.R. [Colegio de Ciencias e Ingeniería, Universidad San Francisco de Quito, Quito (Ecuador); Caneiro, A. [Instituto Balseiro - Centro Atómico Bariloche, 8400 Bariloche (Argentina); Niebieskikwiat, D., E-mail: dniebieskikwiat@usfq.edu.ec [Colegio de Ciencias e Ingeniería, Universidad San Francisco de Quito, Quito (Ecuador)

    2015-10-15

    We study the physical properties of the antiferromagnetic spin ladder CaV{sub 2}O{sub 4} (CVO) and the Y-doped related compound Ca{sub 0.9}Y{sub 0.1}V{sub 2}O{sub 4}. In the latter, X-ray diffraction demonstrates the segregation of a small amount of a vanadium–perovskite impurity phase, leading to the formation of V vacancies within the main CVO-type structure. The 1D character of this calcium–vanadite enhances the influence of the vacancies on the electric and magnetic properties of Ca{sub 0.9}Y{sub 0.1}V{sub 2}O{sub 4}. Electrical transport is characterized by a variable-range hopping mechanism determined by the charging energy of nm-sized segments of V chains delimited by V vacancies, i.e. a Coulomb gap is formed at the Fermi level. These vacancies also locally affect the magnetic correlations, breaking the long-range AFM order observed in CaV{sub 2}O{sub 4} and producing exchange bias when the Y-doped sample is cooled with an applied magnetic field. - Highlights: • We study disorder effects in the quasi-1D antiferromagnetic spin ladder CaV{sub 2}O{sub 4}. • V vacancies in CaV{sub 2}O{sub 4} lead to variable-range hopping electrical transport. • The charging energy of nm-sized V chains determine the transport mechanism exponents. • V vacancies break the long-range AFM order of CaV{sub 2}O{sub 4}. • Local magnetic correlations in the vicinity of the defects produce exchange bias.

  6. High energy, high average power solid state green or UV laser

    Science.gov (United States)

    Hackel, Lloyd A.; Norton, Mary; Dane, C. Brent

    2004-03-02

    A system for producing a green or UV output beam for illuminating a large area with relatively high beam fluence. A Nd:glass laser produces a near-infrared output by means of an oscillator that generates a high quality but low power output and then multi-pass through and amplification in a zig-zag slab amplifier and wavefront correction in a phase conjugator at the midway point of the multi-pass amplification. The green or UV output is generated by means of conversion crystals that follow final propagation through the zig-zag slab amplifier.

  7. Optimizing ZigBee Security using Stochastic Model Checking

    DEFF Research Database (Denmark)

    Yuksel, Ender; Nielson, Hanne Riis; Nielson, Flemming

    , we identify an important gap in the specification on key updates, and present a methodology for determining optimal key update policies and security parameters. We exploit the stochastic model checking approach using the probabilistic model checker PRISM, and assess the security needs for realistic......ZigBee is a fairly new but promising wireless sensor network standard that offers the advantages of simple and low resource communication. Nevertheless, security is of great concern to ZigBee, and enhancements are prescribed in the latest ZigBee specication: ZigBee-2007. In this technical report...

  8. Frustrated quantum magnetism in the Kondo lattice on the zigzag ladder

    Science.gov (United States)

    Peschke, Matthias; Rausch, Roman; Potthoff, Michael

    2018-03-01

    The interplay between the Kondo effect, indirect magnetic interaction, and geometrical frustration is studied in the Kondo lattice on the one-dimensional zigzag ladder. Using the density-matrix renormalization group, the ground-state and various short- and long-range spin- and density-correlation functions are calculated for the model at half filling as a function of the antiferromagnetic Kondo interaction down to J =0.3 t , where t is the nearest-neighbor hopping on the zigzag ladder. Geometrical frustration is shown to lead to at least two critical points: Starting from the strong-J limit, where almost local Kondo screening dominates and where the system is a nonmagnetic Kondo insulator, antiferromagnetic correlations between nearest-neighbor and next-nearest-neighbor local spins become stronger and stronger, until at Jcdim≈0.89 t frustration is alleviated by a spontaneous breaking of translational symmetry and a corresponding transition to a dimerized state. This is characterized by antiferromagnetic correlations along the legs and by alternating antiferro- and ferromagnetic correlations on the rungs of the ladder. A mechanism of partial Kondo screening that has been suggested for the Kondo lattice on the two-dimensional triangular lattice is not realized in the one-dimensional case. Furthermore, within the symmetry-broken dimerized state, there is a magnetic transition to a 90∘ quantum spin spiral with quasi-long-range order at Jcmag≈0.84 t . The quantum-critical point is characterized by a closure of the spin gap (with decreasing J ) and a divergence of the spin-correlation length and of the spin-structure factor S (q ) at wave vector q =π /2 . This is opposed to the model on the one-dimensional bipartite chain, which is known to have a finite spin gap for all J >0 at half filling.

  9. ESR modes in a Strong-Leg Ladder in the Tomonaga-Luttinger Liquid Phase

    Science.gov (United States)

    Zvyagin, S.; Ozerov, M.; Maksymenko, M.; Wosnitza, J.; Honecker, A.; Landee, C. P.; Turnbull, M.; Furuya, S. C.; Giamarchi, T.

    Magnetic excitations in the strong-leg quantum spin ladder compound (C7H10N)2CuBr4 (known as DIMPY) in the field-induced Tomonaga-Luttinger spin liquid phase are studied by means of high-field electron spin resonance (ESR) spectroscopy. The presence of a gapped ESR mode with unusual non-linear frequency-field dependence is revealed experimentally. Using a combination of analytic and exact diagonalization methods, we compute the dynamical structure factor and identify this mode with longitudinal excitations in the antisymmetric channel. We argue that these excitations constitute a fingerprint of the spin dynamics in a strong-leg spin-1/2 Heisenberg antiferromagnetic ladder and owe its ESR observability to the uniform Dzyaloshinskii-Moriya interaction. This work was partially supported by the DFG and Helmholtz Gemeinschaft (Germany), Swiss SNF under Division II, and ERC synergy UQUAM project. We acknowledge the support of the HLD at HZDR, member of the European Magnetic Field Laboratory (EMFL).

  10. Low-Field Bi-Skyrmion Formation in a Noncentrosymmetric Chimney Ladder Ferromagnet

    Science.gov (United States)

    Takagi, R.; Yu, X. Z.; White, J. S.; Shibata, K.; Kaneko, Y.; Tatara, G.; Rønnow, H. M.; Tokura, Y.; Seki, S.

    2018-01-01

    The real-space spin texture and the relevant magnetic parameters were investigated for an easy-axis noncentrosymmetric ferromagnet Cr11 Ge19 with Nowotny chimney ladder structure. Using Lorentz transmission electron microscopy, we report the formation of bi-Skyrmions, i.e., pairs of spin vortices with opposite magnetic helicities. The quantitative evaluation of the magnetocrystalline anisotropy and Dzyaloshinskii-Moriya interaction (DMI) proves that the magnetic dipolar interaction plays a more important role than the DMI on the observed bi-Skyrmion formation. Notably, the critical magnetic field value required for the formation of bi-Skyrmions turned out to be extremely small in this system, which is ascribed to strong easy-axis anisotropy associated with the characteristic helix crystal structure. The family of Nowotny chimney ladder compounds may offer a unique material platform where two distinctive Skyrmion formation mechanisms favoring different topological spin textures can become simultaneously active.

  11. Exploration and design of smart home circuit based on ZigBee

    Science.gov (United States)

    Luo, Huirong

    2018-05-01

    To apply ZigBee technique in smart home circuit design, in the hardware design link of ZigBee node, TI Company's ZigBee wireless communication chip CC2530 was used to complete the design of ZigBee RF module circuit and peripheral circuit. In addition, the function demand and the overall scheme of the intelligent system based on smart home furnishing were proposed. Finally, the smart home system was built by combining ZigBee network and intelligent gateway. The function realization, reliability and power consumption of ZigBee network were tested. The results showed that ZigBee technology was applied to smart home system, making it have some advantages in terms of flexibility, scalability, power consumption and indoor aesthetics. To sum up, the system has high application value.

  12. The search for competing charge orders in frustrated ladder systems

    International Nuclear Information System (INIS)

    Lal, Siddhartha; Laad, Mukul S.

    2007-08-01

    A recent study revealed the dynamics of the charge sector of a one-dimensional quarter- filled electronic system with extended Hubbard interactions to be that of an effective pseudospin transverse-field Ising model (TFIM) in the strong coupling limit. With the twin motivations of studying the co-existing charge and spin order found in strongly correlated chain systems and the effects of inter-chain couplings, we investigate the phase diagram of coupled effective (TFIM) systems. A bosonisation and RG analysis for a two-leg TFIM ladder yields a rich phase diagram showing Wigner/Peierls charge order and Neel/dimer spin order. In a broad parameter regime, the orbital antiferromagnetic phase is found to be stable. An intermediate gapless phase of finite width is found to lie in between two charge-ordered gapped phases. Kosterlitz-Thouless transitions are found to lead from the gapless phase to either of the charge-ordered phases. Low energy effective Hamiltonian analyses of a strongly coupled 2-chain ladder system confirm a phase diagram with in-chain CO, rung-dimer, and orbital antiferromagnetic ordered phases with varying interchain couplings as well as superconductivity upon hole-doping. Our work is potentially relevant for a unified description of a class of strongly correlated, quarter-filled chain and ladder systems. (autor)

  13. Detecting phase boundaries of quantum spin-1/2 XXZ ladder via bipartite and multipartite entanglement transitions

    Science.gov (United States)

    Singha Roy, Sudipto; Dhar, Himadri Shekhar; Rakshit, Debraj; Sen(De), Aditi; Sen, Ujjwal

    2017-12-01

    Phase transition in quantum many-body systems inevitably causes changes in certain physical properties which then serve as potential indicators of critical phenomena. Besides the traditional order parameters, characterization of quantum entanglement has proven to be a computationally efficient and successful method for detection of phase boundaries, especially in one-dimensional models. Here we determine the rich phase diagram of the ground states of a quantum spin-1/2 XXZ ladder by analyzing the variation of bipartite and multipartite entanglements. Our study characterizes the different ground state phases and notes the correspondence with known results, while highlighting the finer details that emerge from the behavior of ground state entanglement. Analysis of entanglement in the ground state provides a clearer picture of the complex ground state phase diagram of the system using only a moderate-size model.

  14. Blockage of ultrafast and directional diffusion of Li atoms on phosphorene with intrinsic defects.

    Science.gov (United States)

    Zhang, Ruiqi; Wu, Xiaojun; Yang, Jinlong

    2016-02-21

    The diffusion of Li in electrode materials is a key factor for the charging/discharging rate capacity of a Li-ion battery (LIB). Recently, two-dimensional phosphorene has been proposed as a very promising electrode material due to its ultrafast and directional lithium diffusion, as well as large energy capacity. Herein, on the basis of density functional theory, we report that intrinsic point defects, including vacancy and stone-wales defects, will block the directional ultrafast diffusion of lithium in phosphorene. On the defect-free phosphorene, diffusion of Li along the zig-zag lattice direction is 1.6 billion times faster than along the armchair lattice direction, and 260 times faster than that in graphite. After introducing intrinsic vacancy and stone-wales defect, the diffusion energy barrier of Li along the zig-zag lattice direction increases sharply to the range of 0.17-0.49 eV, which blocks the ultrafast migration of lithium along the zig-zag lattice direction. Moreover, the open circuit voltage increases with the emergence of defects, which is not suitable for anode materials. In addition, the formation energies of the defects in phosphorene are considerably lower than those in graphene and silicene sheet; therefore, it is highly important to generate defect-free phosphorene for LIB applications.

  15. The Zig-zag Instability of Streamlined Bodies

    Science.gov (United States)

    Guillet, Thibault; Coux, Martin; Quere, David; Clanet, Christophe

    2017-11-01

    When a floating bluff body, like a sphere, impacts water with a vertical velocity, its trajectory is straight and the depth of its dive increases with its initial velocity. Even though we observe the same phenomenon at low impact speed for axisymmetric streamlined bodies, the trajectory is found to deviate from the vertical when the velocity overcomes a critical value. This instability results from a competition between the destabilizing torque of the lift and the stabilizing torque of the Archimede's force. Balancing these torques yields a prediction on the critical velocity above which the instability appears. This theoretical value is found to depend on the position of the gravity center of the projectile and predicts with a full agreement the behaviour observed in our different experiments. Project funded by DGA.

  16. Ladder Safety Live #12985

    Energy Technology Data Exchange (ETDEWEB)

    Chochoms, Michael [Los Alamos National Laboratory

    2017-02-23

    This course presents information for working safely with portable ladders: specifically, stepladders, extensions ladders, and their derivations. Additionally, this course provides limited information on the safe use of stepstools and fixed ladders. The skills, techniques, and good practices needed for selecting, inspecting, setting up and securing, and using ladders are presented in this course.

  17. One-dimensional Co(II)/Ni(II) complexes of 2-hydroxyisophthalate: Structures and magnetic properties

    International Nuclear Information System (INIS)

    Wang, Kai; Zou, Hua-Hong; Chen, Zi-Lu; Zhang, Zhong; Sun, Wei-Yin; Liang, Fu-Pei

    2015-01-01

    The solvothermal reactions of 2-hydroxyisophthalic acid (H 3 ipO) with M(NO 3 ) 2 ∙6H 2 O (M=Co, Ni) afforded two complexes [Co 2 (HipO) 2 (Py) 2 (H 2 O) 2 ] (1) and [Ni(HipO)(Py)H 2 O] (2) (Py=pyridine). They exhibit similar zig-zag chain structures with the adjacent two metal centers connected by a anti-syn bridging carboxylate group from the HipO 2− ligand. The magnetic measurements reveal the dominant antiferromagnetic interactions and spin-canting in 1 while ferromagnetic interactions in 2. Both of them exhibit magnetocaloric effect (MCE) with the resulting entropy changes (−ΔS m ) of 12.51 J kg −1 K −1 when ΔH=50 kOe at 3 K for 1 and 11.01 J kg −1 K −1 when ΔH=50 kOe at 3 K for 2, representing the rare examples of one-dimensional complexes with MCE. - Graphical abstract: Synopsis: Two Co(II)/Ni(II) complexes with zig-zag chain structures have been reported. 1-Co shows cant-antiferromagnetism while 2-Ni shows ferromagnetism. Magnetocaloric effect is also found in both of them. - Highlights: • Two one-dimensional Co(II)/Ni(II) complexes were solvothermally synthesized. • The Co-complex exhibits canted antiferromagnetism. • The Ni-complex exhibits ferromagnetism. • Both of the complexes display magnetocaloric effect

  18. Comparison of ZigBee Replay Attacks Using a Universal Software Radio Peripheral and USB Radio

    Science.gov (United States)

    2014-03-27

    necessary for embedded devices. One such solution is the ZigBee protocol. ZigBee is commonly used in home automation , health care networks, and the smart...specific use of ZigBee. They include ZigBee Building Automation, Remote Control, Smart Energy, Smart Energy 4 Profile 2, Health Care, Home Automation , Input

  19. Effective career ladders.

    Science.gov (United States)

    Bryant, B; Rabbitts, D; Shover, J; Torres, M; VanDerHeyden, B; Violand-Jones, S

    1992-01-01

    Motivation, quality improvement, productivity enhancement. These are just some of the benefits of an effective career ladder program. The key term here is effective. It is easy for laboratory personnel to stagnate professionally if they do not have a career ladder program, but it is even easier for them to become frustrated--even cynical--over a program that fails to live up to its expectations to encourage, support, and reward professional advancement. If you have been looking form some ideas to get your own career ladder program off the ground, the following responses from your colleagues may help as CLMR asks: What makes your career ladder program effective?

  20. Available friction of ladder shoes and slip potential for climbing on a straight ladder.

    Science.gov (United States)

    Chang, Wen-Ruey; Chang, Chien-Chi; Matz, Simon

    2005-07-15

    Straight ladder accidents are a major safety problem. As a leading cause of injuries involving straight ladders, slips at the ladder base occur when the required friction exceeds the available friction at the ladder shoe and floor interface. The objectives of this experiment were to measure the available friction at the base of a portable straight ladder in contact with a floor and to estimate the slip potential of the ladder. The results of friction measurements indicated that the measured friction coefficient on the oily surfaces differed among the six commercially available ladder shoes evaluated. A statistical model was used to compare the available friction results from the current study with the friction requirements under different climbing conditions from a previous study based on their stochastic distributions to estimate the slip potential at the base of the ladder. The results showed that different climbing conditions used in the previous study could be supported by available friction on dry surfaces. However, when the ladder was put onto oily surfaces, resulting in a significant reduction in the available friction due to contamination, slip potential was significantly increased.

  1. Ground-state and spectral properties of an asymmetric Hubbard ladder

    Science.gov (United States)

    Abdelwahab, Anas; Jeckelmann, Eric; Hohenadler, Martin

    2015-04-01

    We investigate a ladder system with two inequivalent legs, namely, a Hubbard chain and a one-dimensional electron gas. Analytical approximations, the density-matrix renormalization group method, and continuous-time quantum Monte Carlo simulations are used to determine ground-state properties, gaps, and spectral functions of this system at half-filling. Evidence for the existence of four different phases as a function of the Hubbard interaction and the rung hopping is presented. First, a Luttinger liquid exists at very weak interchain hopping. Second, a Kondo-Mott insulator with spin and charge gaps induced by an effective rung exchange coupling is found at moderate interchain hopping or strong Hubbard interaction. Third, a spin-gapped paramagnetic Mott insulator with incommensurate excitations and pairing of doped charges is observed at intermediate values of the rung hopping and the interaction. Fourth, the usual correlated band insulator is recovered for large rung hopping. We show that the wave numbers of the lowest single-particle excitations are different in each insulating phase. In particular, the three gapped phases exhibit markedly different spectral functions. We discuss the relevance of asymmetric two-leg ladder systems as models for atomic wires deposited on a substrate.

  2. Effect of thermal cycling on the microstructure of a directionally solidified Fe, Cr, Al-TaC eutectic alloy

    Science.gov (United States)

    Harf, F. H.; Tewari, S. N.

    1977-01-01

    Cylindrical bars (1.2 cm diameter) of Fe-13.6Cr-3.7Al-9TaC (wt %) eutectic alloy were directionally solidified in a modified Bridgman type furnace at 1 cm/h. The alloy microstructure consisted of aligned TaC fibers imbedded in a bcc Fe-Cr-Al matrix. Specimens of the alloy were thermally cycled from 1100 to 425 C in a burner rig. The effects of 1800 thermal cycles on the microstructure was examined by scanning electron microscopy, revealing a zig-zag shape of TaC fibers aligned parallel to the growth direction. The mechanism of carbide solution and reprecipitation on the (111) easy growth planes, suggested previously to account for the development of irregular serrations in Co-Cr-Ni matrix alloys, is believed to be responsible for these zig-zag surfaces.

  3. Development of LD pumped 10 J x 10 Hz Nd: Glass slab laser system

    International Nuclear Information System (INIS)

    Yamanaka, Masanobu; Kanabe, Tadashi; Matsui, Hideki

    2000-01-01

    As a first step of a driver development for the inertial fusion energy, we are developing a diode-pumped zig-zag Nd: glass slab laser amplifier system which can generate an output of 10 J per pulse at 1053 nm in 10 Hz operation. The water-cooled zig-zag Nd: glass slab is pumped from both sides by 803-nm AlGaAs laser-diode (LD) module; each LD module has an emitting area of 420 mm x 10 mm and two LD modules generated in total 200 kW peak power with 2.5 kW/cm 2 peak intensity at 10 Hz repetition rate. We have obtained in a preliminary experiment a 8.5 J output energy at 0.5 Hz with beam quality of 2 times diffraction limited far-field pattern. (author)

  4. Arduino-lämpömittari ZigBee-yhteydellä

    OpenAIRE

    Laukkanen, Jani-Pekka

    2013-01-01

    Opinnäytetyön tarkoitus oli toteuttaa lämpötila-anturilla varustettu Arduino, joka lähettää anturin tiedot langattomalla ZigBee-yhteydellä toiselle Arduinolle. Toinen Arduino vastaanottaa datan ja tulostaa sen näytölle. Lämpötila-anturi ja näyttö voivat siis olla fyysisesti eri paikoissa ZigBee-yhteyden kantaman sisällä. Valmis tuotos jäi omaan käyttöön ja sitä käytetään varastotilan lämpötilan seurantaan. Teoriaosuudessa käsiteltiin Arduino-kehitysalustan ja ZigBee-tekniikan perusteita. ...

  5. Design of smart home terminal controller based on ZigBee

    Science.gov (United States)

    Li, Biqing; Li, Zhao; Zhang, Hongyan

    2018-04-01

    With the development in scienc and technology, and the improvement of living conditions, people pay more and more attention to the comfort of household life. Therefore, smart home has become the development trend of the future furniture. This design is composed of three blocks: transmitting module, receiving module and data acquisition module. ZigBee and STC89C52 belong to launch module as well as belong to receive module. Launch module contains ZigBee, serial communication module and monolithic STC89C52. The receiving module contains light control parts, curtain control part, ZigBee and microcontroller STC89C52. Data acquisition module includes temperature and humidity detection.

  6. Knitting distributed cluster-state ladders with spin chains

    Energy Technology Data Exchange (ETDEWEB)

    Ronke, R.; D' Amico, I. [Department of Physics, University of York, York YO10 5DD, United Kingdom. (United Kingdom); Spiller, T. P. [School of Physics and Astronomy, E C Stoner Building, University of Leeds, Leeds, LS2 9JT (United Kingdom)

    2011-09-15

    Recently there has been much study on the application of spin chains to quantum state transfer and communication. Here we discuss the utilization of spin chains (set up for perfect quantum state transfer) for the knitting of distributed cluster-state structures, between spin qubits repeatedly injected and extracted at the ends of the chain. The cluster states emerge from the natural evolution of the system across different excitation number sectors. We discuss the decohering effects of errors in the injection and extraction process as well as the effects of fabrication and random errors.

  7. Knitting distributed cluster-state ladders with spin chains

    International Nuclear Information System (INIS)

    Ronke, R.; D'Amico, I.; Spiller, T. P.

    2011-01-01

    Recently there has been much study on the application of spin chains to quantum state transfer and communication. Here we discuss the utilization of spin chains (set up for perfect quantum state transfer) for the knitting of distributed cluster-state structures, between spin qubits repeatedly injected and extracted at the ends of the chain. The cluster states emerge from the natural evolution of the system across different excitation number sectors. We discuss the decohering effects of errors in the injection and extraction process as well as the effects of fabrication and random errors.

  8. 29 CFR 1926.1053 - Ladders.

    Science.gov (United States)

    2010-07-01

    ... plastic ladder shall sustain at least 3.3 times the maximum intended load. The ability of a ladder to... that each extra-heavy-duty type 1A metal or plastic ladders shall sustain at least 3.3 times the... from anticipated usage of the ladder, shall also be included), plus anticipated loads caused by ice...

  9. ZigBee wireless sensor network for environmental monitoring system

    Science.gov (United States)

    Chai, Shun-qi; Ji, Lei; Wu, Hong

    2009-11-01

    ZigBee is a new close-up, low-complexity, low-power, low data rate, low-cost wireless networking technology, mainly used for short distance wireless transmission. It is based on IEEE802.15.4 standards, thousands of tiny sensors form a network through mutual coordination to communications. This paper introduces the ZigBee wireless sensor networks in environmental monitoring applications. The hardware design, including microprocessor, data acquisition, antenna and peripheral circuits of the chips, and through software design composed ZigBee mesh network that can make data acquisition and communication. This network has low power consumption, low cost, the effective area is big, and information transfers reliable merits. And have confirmed the network's communication applicability by the Serial Com Assistant, also testified the network have very good pragmatism by the NS2 emulation the network's operation.

  10. Magnetic field effects of tow-leg Heisenberg antiferromagnetic ladders: Thermodynamic properties

    International Nuclear Information System (INIS)

    Wang Xiaoqun; Yu Lu

    2000-05-01

    Using the recently developed transfer-matrix renormalization group method, we have studied the thermodynamic properties of two-leg antiferromagnetic ladders in the magnetic field. Based on different behavior of magnetization, we found disordered spin liquid, Luttinger liquid, spin-polarized phases and a classical regime depending on magnetic field and temperature. Our calculations in Luttinger liquid regime suggest that both the divergence of the NMR relaxation rate and the anomalous specific heat behavior observed on Cu 2 (C 5 H 12 N 2 ) 2 Cl 4 are due to quasi-one-dimensional effect rather than three-dimensional ordering. (author)

  11. An excitable cortex and memory model successfully predicts new pseudopod dynamics.

    Directory of Open Access Journals (Sweden)

    Robert M Cooper

    Full Text Available Motile eukaryotic cells migrate with directional persistence by alternating left and right turns, even in the absence of external cues. For example, Dictyostelium discoideum cells crawl by extending distinct pseudopods in an alternating right-left pattern. The mechanisms underlying this zig-zag behavior, however, remain unknown. Here we propose a new Excitable Cortex and Memory (EC&M model for understanding the alternating, zig-zag extension of pseudopods. Incorporating elements of previous models, we consider the cell cortex as an excitable system and include global inhibition of new pseudopods while a pseudopod is active. With the novel hypothesis that pseudopod activity makes the local cortex temporarily more excitable--thus creating a memory of previous pseudopod locations--the model reproduces experimentally observed zig-zag behavior. Furthermore, the EC&M model makes four new predictions concerning pseudopod dynamics. To test these predictions we develop an algorithm that detects pseudopods via hierarchical clustering of individual membrane extensions. Data from cell-tracking experiments agrees with all four predictions of the model, revealing that pseudopod placement is a non-Markovian process affected by the dynamics of previous pseudopods. The model is also compatible with known limits of chemotactic sensitivity. In addition to providing a predictive approach to studying eukaryotic cell motion, the EC&M model provides a general framework for future models, and suggests directions for new research regarding the molecular mechanisms underlying directional persistence.

  12. Dedicated real-time monitoring system for health care using ZigBee.

    Science.gov (United States)

    Alwan, Omar S; Prahald Rao, K

    2017-08-01

    Real-time monitoring systems (RTMSs) have drawn considerable attentions in the last decade. Several commercial versions of RTMS for patient monitoring are available which are used by health care professionals. Though they are working satisfactorily on various communication protocols, their range, power consumption, data rate and cost are really bothered. In this study, the authors present an efficient embedded system based wireless health care monitoring system using ZigBee. Their system has a capability to transmit the data between two embedded systems through two transceivers over a long range. In this, wireless transmission has been applied through two categories. The first part which contains Arduino with ZigBee will send the signals to the second device, which contains Raspberry with ZigBee. The second device will measure the patient data and send it to the first device through ZigBee transceiver. The designed system is demonstrated on volunteers to measure the body temperature which is clinically important to monitor and diagnose for fever in the patients.

  13. Short communications

    African Journals Online (AJOL)

    suggested that they were casualties of low-level flight over smooth, glassy ... moon. Flamingoes sometimes descend from height by zig-zagging down at high .... Although the large quantity of dead animals seen on the first occasion was not.

  14. 29 CFR 1917.119 - Portable ladders.

    Science.gov (United States)

    2010-07-01

    ... Requirements for Portable Reinforced Plastic Ladders (d) Standards for job-made portable ladders. Job-made... usage. (1) Ladders made by fastening rungs or devices across a single rail are prohibited. (2) Ladders...

  15. HomePort ZigBee Adapter

    DEFF Research Database (Denmark)

    Pedersen, Thomas; Smedegaard, Jacob Haubach; Hansen, Rene

    the existing tool, Homeport, to act as a middleware and bridge between ConLAN's existing network and the ZigBee network. This report primarily discusses three possible solutions for constructing this bridge and current status on the implementation of a Develco SmartAMM and Zigbee stack for HomePort....

  16. Electrostatic Manipulation of Graphene On Graphite

    Science.gov (United States)

    Untiedt, Carlos; Rubio-Verdu, Carmen; Saenz-Arce, Giovanni; Martinez-Asencio, Jesús; Milan, David C.; Moaied, Mohamed; Palacios, Juan J.; Caturla, Maria Jose

    2015-03-01

    Here we report the use of a Scanning Tunneling Microscope (STM) under ambient and vacuum conditions to study the controlled exfoliation of the last layer of a graphite surface when an electrostatic force is applied from a STM tip. In this work we have focused on the study of two parameters: the applied voltage needed to compensate the graphite interlayer attractive force and the one needed to break atomic bonds to produce folded structures. Additionally, we have studied the influence of edge structure in the breaking geometry. Independently of the edge orientation the graphite layer is found to tear through the zig-zag direction and the lifled layer shows a zig-zag folding direction. Molecular Dinamics simulations and DFT calculations have been performed to understand our results, showing a strong correlation with the experiments. Comunidad Valenciana through Prometeo project.

  17. A Holistic Approach to ZigBee Performance Enhancement for Home Automation Networks

    Directory of Open Access Journals (Sweden)

    August Betzler

    2014-08-01

    Full Text Available Wireless home automation networks are gaining importance for smart homes. In this ambit, ZigBee networks play an important role. The ZigBee specification defines a default set of protocol stack parameters and mechanisms that is further refined by the ZigBee Home Automation application profile. In a holistic approach, we analyze how the network performance is affected with the tuning of parameters and mechanisms across multiple layers of the ZigBee protocol stack and investigate possible performance gains by implementing and testing alternative settings. The evaluations are carried out in a testbed of 57 TelosB motes. The results show that considerable performance improvements can be achieved by using alternative protocol stack configurations. From these results, we derive two improved protocol stack configurations for ZigBee wireless home automation networks that are validated in various network scenarios. In our experiments, these improved configurations yield a relative packet delivery ratio increase of up to 33.6%, a delay decrease of up to 66.6% and an improvement of the energy efficiency for battery powered devices of up to 48.7%, obtainable without incurring any overhead to the network.

  18. A Holistic Approach to ZigBee Performance Enhancement for Home Automation Networks

    Science.gov (United States)

    Betzler, August; Gomez, Carles; Demirkol, Ilker; Paradells, Josep

    2014-01-01

    Wireless home automation networks are gaining importance for smart homes. In this ambit, ZigBee networks play an important role. The ZigBee specification defines a default set of protocol stack parameters and mechanisms that is further refined by the ZigBee Home Automation application profile. In a holistic approach, we analyze how the network performance is affected with the tuning of parameters and mechanisms across multiple layers of the ZigBee protocol stack and investigate possible performance gains by implementing and testing alternative settings. The evaluations are carried out in a testbed of 57 TelosB motes. The results show that considerable performance improvements can be achieved by using alternative protocol stack configurations. From these results, we derive two improved protocol stack configurations for ZigBee wireless home automation networks that are validated in various network scenarios. In our experiments, these improved configurations yield a relative packet delivery ratio increase of up to 33.6%, a delay decrease of up to 66.6% and an improvement of the energy efficiency for battery powered devices of up to 48.7%, obtainable without incurring any overhead to the network. PMID:25196004

  19. A holistic approach to ZigBee performance enhancement for home automation networks.

    Science.gov (United States)

    Betzler, August; Gomez, Carles; Demirkol, Ilker; Paradells, Josep

    2014-08-14

    Wireless home automation networks are gaining importance for smart homes. In this ambit, ZigBee networks play an important role. The ZigBee specification defines a default set of protocol stack parameters and mechanisms that is further refined by the ZigBee Home Automation application profile. In a holistic approach, we analyze how the network performance is affected with the tuning of parameters and mechanisms across multiple layers of the ZigBee protocol stack and investigate possible performance gains by implementing and testing alternative settings. The evaluations are carried out in a testbed of 57 TelosB motes. The results show that considerable performance improvements can be achieved by using alternative protocol stack configurations. From these results, we derive two improved protocol stack configurations for ZigBee wireless home automation networks that are validated in various network scenarios. In our experiments, these improved configurations yield a relative packet delivery ratio increase of up to 33.6%, a delay decrease of up to 66.6% and an improvement of the energy efficiency for battery powered devices of up to 48.7%, obtainable without incurring any overhead to the network.

  20. A Secure Key Establishment Protocol for ZigBee Wireless Sensor Networks

    DEFF Research Database (Denmark)

    Yuksel, Ender; Nielson, Hanne Riis; Nielson, Flemming

    2010-01-01

    ZigBee is a wireless sensor network standard that defines network and application layers on top of IEEE 802.15.4's physical and medium access control layers. In the latest version of ZigBee, enhancements are prescribed for the security sublayer but we show in this paper that problems persist...

  1. Solitary Magnons in the S =5/2 Antiferromagnet CaFe2O4

    Science.gov (United States)

    Stock, C.; Rodriguez, E. E.; Lee, N.; Green, M. A.; Demmel, F.; Ewings, R. A.; Fouquet, P.; Laver, M.; Niedermayer, Ch.; Su, Y.; Nemkovski, K.; Rodriguez-Rivera, J. A.; Cheong, S.-W.

    2016-07-01

    CaFe2O4 is a S =5/2 anisotropic antiferromagnet based upon zig-zag chains having two competing magnetic structures, denoted as the A (↑↑↓↓) and B (↑↓↑↓) phases, which differ by the c -axis stacking of ferromagnetic stripes. We apply neutron scattering to demonstrate that the competing A and B phase order parameters result in magnetic antiphase boundaries along c which freeze on the time scale of ˜1 ns at the onset of magnetic order at 200 K. Using high resolution neutron spectroscopy, we find quantized spin wave levels and measure 9 such excitations localized in regions ˜1 - 2 c -axis lattice constants in size. We discuss these in the context of solitary magnons predicted to exist in anisotropic systems. The magnetic anisotropy affords both competing A +B orders as well as localization of spin excitations in a classical magnet.

  2. Chain and ladder models with two-body interactions and analytical ground states

    Science.gov (United States)

    Manna, Sourav; Nielsen, Anne E. B.

    2018-05-01

    We consider a family of spin-1 /2 models with few-body, SU(2)-invariant Hamiltonians and analytical ground states related to the one-dimensional (1D) Haldane-Shastry wave function. The spins are placed on the surface of a cylinder, and the standard 1D Haldane-Shastry model is obtained by placing the spins with equal spacing in a circle around the cylinder. Here, we show that another interesting family of models with two-body exchange interactions is obtained if we instead place the spins along one or two lines parallel to the cylinder axis, giving rise to chain and ladder models, respectively. We can change the scale along the cylinder axis without changing the radius of the cylinder. This gives us a parameter that controls the ratio between the circumference of the cylinder and all other length scales in the system. We use Monte Carlo simulations and analytical investigations to study how this ratio affects the properties of the models. If the ratio is large, we find that the two legs of the ladder decouple into two chains that are in a critical phase with Haldane-Shastry-like properties. If the ratio is small, the wave function reduces to a product of singlets. In between, we find that the behavior of the correlations and the Renyi entropy depends on the distance considered. For small distances the behavior is critical, and for long distances the correlations decay exponentially and the entropy shows an area law behavior. The distance up to which there is critical behavior gets larger as the ratio increases.

  3. Resonance – Journal of Science Education | Indian Academy of ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 19; Issue 9. Converting Chair-like Transition States into Zig-Zag Projections: A Method of Drawing Stereochemical Structures. Syed R Hussaini. Classroom Volume 19 Issue 9 September 2014 pp 846-850 ...

  4. Resonance – Journal of Science Education | Indian Academy of ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 4. Interconversion of Fischer and Zig-Zag Projections - Learning Stereochemistry with the Help of Hands. Syed R Hussaini. Classroom Volume 15 Issue 4 April 2010 pp 351-354 ...

  5. A Secure Key Establishment Protocol for ZigBee Wireless Sensor Networks

    DEFF Research Database (Denmark)

    Yuksel, Ender; Nielson, Hanne Riis; Nielson, Flemming

    2009-01-01

    ZigBee is a wireless sensor network standard that defines network and application layers on top of IEEE 802.15.4’s physical and medium access control layers. In the latest version of ZigBee, enhancements are prescribed for the security sublayer but we show in this paper that problems persist....... In particular we show that the End-to-End Application Key Establishment Protocol is flawed and we propose a secure protocol instead. We do so by using formal verification techniques based on static program analysis and process algebras. We present a way of using formal methods in wireless network security......, and propose a secure key establishment protocol for ZigBee networks....

  6. Design of smart home gateway based on Wi-Fi and ZigBee

    Science.gov (United States)

    Li, Yang

    2018-04-01

    With the increasing demand for home lifestyle, the traditional smart home products have been unable to meet the needs of users. Aim at the complex wiring, high cost and difficult operation problems of traditional smart home system, this paper designs a home gateway for smart home system based on Wi-Fi and ZigBee. This paper first gives a smart home system architecture base on cloud server, Wi-Fi and ZigBee. This architecture enables users to access the smart home system remotely from Internet through the cloud server or through Wi-Fi at home. It also offers the flexibility and low cost of ZigBee wireless networking for home equipment. This paper analyzes the functional requirements of the home gateway, and designs a modular hardware architecture based on the RT5350 wireless gateway module and the CC2530 ZigBee coordinator module. Also designs the software of the home gateway, including the gateway master program and the ZigBee coordinator program. Finally, the smart home system and home gateway are tested in two kinds of network environments, internal network and external network. The test results show that the designed home gateway can meet the requirements, support remote and local access, support multi-user, support information security technology, and can timely report equipment status information.

  7. Development of Moving Bed Technology for Heat Treatment and Grinding of Dismantled Concrete

    International Nuclear Information System (INIS)

    Kang, Yong

    2009-04-01

    The factors such as gas or fluid velocity, length, width and depth of each stage, number of Zig-Zag stage, angle of each stage, position of feed stage, size and amount of feed material, amount of treated concrete waste, method of fluid distribution, surface area of heat transfer, position of heater, method of heating, temperature difference between the heater and the material, amount of heat have been found to be important factors in the system. The capability of the system has been analyzed and evaluated by means of total efficiency and grade separation efficiency the experiments by using the simulated Zig-Zag type moving bed flow process with bench scale(3.2m high, Ifi-stage) have shown that the total efficiency has been in the range of 92% - 95% and the grade efficiency of 93% - 95%, respectively, elucidating that the system is quite good

  8. Measuring the diameter of rising gas bubbles by means of the ultrasound transit time technique

    Energy Technology Data Exchange (ETDEWEB)

    Richter, T., E-mail: Thomas.Richter6@tu-dresden.de; Eckert, K., E-mail: Kerstin.Eckert@tu-dresden.de; Yang, X.; Odenbach, S.

    2015-09-15

    Highlights: • Ultrasound transit time technique (UTTT) is applied to the zig-zag raise of gas bubble. • Comparison of bubble diameter and tilt, measured by UTTT, with high-speed imaging. • Uncertainty in the determination of the bubble diameter by UTTT is less than 7%. • UTTT is able to measure dynamic changes in bubble size in opaque liquids and vessels. • UTTT can be applied to liquid metal loops. - Abstract: This study presents ultrasound transit time technique (UTTT) measurements of the diameter variations of single argon bubbles rising in a zig-zag trajectory in water. Simultaneous size measurements with a high-speed camera show that UTTT resolves both the apparent diameter and the tilt of the bubble axis with an accuracy of better than 7%. This qualifies UTTT for the measurement of bubble sizes in opaque liquids, such as liquid metals, or vessels.

  9. 29 CFR 1915.72 - Ladders.

    Science.gov (United States)

    2010-07-01

    ...). (b) Construction of portable wood cleated ladders up to 30 feet in length. (1) Wood side rails shall... shall be at least 25/32×33/4 inches in cross section. (c) Construction of portable wood cleated ladders... split side rails, or other faulty or defective construction is prohibited. When ladders with such...

  10. A Study of RF Link and Coverage in ZigBee

    Directory of Open Access Journals (Sweden)

    Doru Suciu

    2010-06-01

    Full Text Available To implement a ZigBee network, wave propagation models are necessary to determine propagation characteristics for installation of these short-range networks of industrial, scientific, and medical (ISM applications but also consumer electronics and smart home appliances. Most applications are deployed indoor, so a very large variety of situations will be met. Using propagations models for indoor environment, the distances between nodes for a reliable RF link, using standard ZigBee devices were determined.

  11. Flexible spintronic devices on Kapton

    DEFF Research Database (Denmark)

    Bedoya-Pinto, Amilcar; Donolato, Marco; Gobbi, Marco

    2014-01-01

    Magnetic tunnel junctions and nano-sized domain-wall conduits have been fabricated on the flexible substrate Kapton. Despite the delicate nature of tunneling barriers and zig-zag shaped nanowires, the devices show an outstanding integrity and robustness upon mechanical bending. High values of ben...

  12. Ising versus S U (2) 2 string-net ladder

    Science.gov (United States)

    Vidal, Julien

    2018-03-01

    We consider the string-net model obtained from S U (2) 2 fusion rules. These fusion rules are shared by two different sets of anyon theories. In this paper, we study the competition between the two corresponding non-Abelian quantum phases in the ladder geometry. A detailed symmetry analysis shows that the nontrivial low-energy sector corresponds to the transverse-field cluster model that displays a critical point described by the s o (2) 1 conformal field theory. Other sectors are obtained by freezing spins in this model.

  13. Rigorous decoupling between edge states in frustrated spin chains and ladders

    Science.gov (United States)

    Chepiga, Natalia; Mila, Frédéric

    2018-05-01

    We investigate the occurrence of exact zero modes in one-dimensional quantum magnets of finite length that possess edge states. Building on conclusions first reached in the context of the spin-1/2 X Y chain in a field and then for the spin-1 J1-J2 Heisenberg model, we show that the development of incommensurate correlations in the bulk invariably leads to oscillations in the sign of the coupling between edge states, and hence to exact zero energy modes at the crossing points where the coupling between the edge states rigorously vanishes. This is true regardless of the origin of the frustration (e.g., next-nearest-neighbor coupling or biquadratic coupling for the spin-1 chain), of the value of the bulk spin (we report on spin-1/2, spin-1, and spin-2 examples), and of the value of the edge-state emergent spin (spin-1/2 or spin-1).

  14. Online Expansion Technology for Dynamic Topology Changing ZigBee Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Md. Emdadul Haque

    2014-03-01

    Full Text Available In ZigBee, the router capable devices have restriction to accept a number of devices as children devices. A router capable device can not allow any new device to join as a child device if it reaches to the maximum capacity of children or depth limit. According to ZigBee specification each device has a permanent 64-bit MAC address. If a device joins a ZigBee network, it receives a short 16-bit MAC address from the parent device. If a device can not join a network, it isolates from the network and becomes an orphan node even though address spaces are available in the network. The orphan problem becomes worse when the topology of the network changes dynamically. In this paper we propose an online expansion technology to connect the maximum number of devices specially for dynamic topology changing ZigBee wireless sensor networks. The proposed technology shares available address spaces of the router devices to reduce the number of orphan nodes in the network.

  15. Phase diagram and quantum order by disorder in the Kitaev K1-K2 honeycomb magnet

    Science.gov (United States)

    Rousochatzakis, Ioannis; Reuther, Johannes; Thomale, Ronny; Rachel, Stephan; Perkins, Natalia

    We show that the topological Kitaev spin liquid on the honeycomb lattice is extremely fragile against the second neighbor Kitaev coupling K2, which has been recently identified as the dominant perturbation away from the nearest neighbor model in iridate Na2IrO3, and may also play a role in α-RuCl3. This coupling explains naturally the zig-zag ordering and the special entanglement between real and spin space observed recently in Na2IrO3. The minimal K1-K2 model that we present here holds in addition the unique property that the classical and quantum phase diagrams and their respective order-by-disorder mechanisms are qualitatively different due to their fundamentally different symmetry structure. Nsf DMR-1511768; Freie Univ. Berlin Excellence Initiative of German Research Foundation; European Research Council, ERC-StG-336012; DFG-SFB 1170; DFG-SFB 1143, DFG-SPP 1666, and Helmholtz association VI-521.

  16. Solitary Magnons in the S=5/2 Antiferromagnet CaFe_{2}O_{4}.

    Science.gov (United States)

    Stock, C; Rodriguez, E E; Lee, N; Green, M A; Demmel, F; Ewings, R A; Fouquet, P; Laver, M; Niedermayer, Ch; Su, Y; Nemkovski, K; Rodriguez-Rivera, J A; Cheong, S-W

    2016-07-01

    CaFe_{2}O_{4} is a S=5/2 anisotropic antiferromagnet based upon zig-zag chains having two competing magnetic structures, denoted as the A (↑↑↓↓) and B (↑↓↑↓) phases, which differ by the c-axis stacking of ferromagnetic stripes. We apply neutron scattering to demonstrate that the competing A and B phase order parameters result in magnetic antiphase boundaries along c which freeze on the time scale of ∼1  ns at the onset of magnetic order at 200 K. Using high resolution neutron spectroscopy, we find quantized spin wave levels and measure 9 such excitations localized in regions ∼1-2 c-axis lattice constants in size. We discuss these in the context of solitary magnons predicted to exist in anisotropic systems. The magnetic anisotropy affords both competing A+B orders as well as localization of spin excitations in a classical magnet.

  17. Experimental evaluation of BZ-GW (BACnet-ZigBee smart grid gateway) for demand response in buildings

    International Nuclear Information System (INIS)

    Hong, Seung Ho; Kim, Se Hwan; Kim, Gi Myung; Kim, Hyung Lae

    2014-01-01

    The SG (smart grid) is a modernized and a future-oriented electric grid that deals with the whole energy chain, from generation to consumer. Among the SG applications, DR (demand response) is an important control mechanism to manage the electricity consumption of the customer in response to supply conditions. In buildings, DR is managed through installed communication networks which support DR applications. BACnet is an international standard communication protocol for building automation and control systems. BACnet uses ZigBee as a wireless communication protocol. Both BACnet and ZigBee have their own DR applications. In this study, we developed a BACnet-ZigBee gateway that maps the DR application of BACnet to that of ZigBee and vice versa. In addition, we developed an experimental facility to demonstrate how the BACnet-ZigBee gateway can be implemented for DR applications in buildings. We also measured the communication delay to verify that the BZ-GW (BACnet-ZigBee smart grid gateway) developed here satisfies the requirements of real-time DR service in buildings. - Highlights: • Developed a gateway that maps the DR application of BACnet to that of ZigBee. • Verified satisfaction for real-time requirement using experimental facility. • The gateway and other device will play a infrastructure role in buildings. • The implementation method could become a reference model for future similar

  18. Wilson loops in minimal surfaces

    International Nuclear Information System (INIS)

    Drukker, Nadav; Gross, David J.; Ooguri, Hirosi

    1999-01-01

    The AdS/CFT correspondence suggests that the Wilson loop of the large N gauge theory with N = 4 supersymmetry in 4 dimensions is described by a minimal surface in AdS 5 x S 5 . The authors examine various aspects of this proposal, comparing gauge theory expectations with computations of minimal surfaces. There is a distinguished class of loops, which the authors call BPS loops, whose expectation values are free from ultra-violet divergence. They formulate the loop equation for such loops. To the extent that they have checked, the minimal surface in AdS 5 x S 5 gives a solution of the equation. The authors also discuss the zig-zag symmetry of the loop operator. In the N = 4 gauge theory, they expect the zig-zag symmetry to hold when the loop does not couple the scalar fields in the supermultiplet. They will show how this is realized for the minimal surface

  19. Laser diode pumped ND: Glass slab laser for inertial fusion energy

    International Nuclear Information System (INIS)

    Yamanaka, M.; Kanabe, T.; Matsui, H.

    2001-01-01

    As a first step of a driver development for the inertial fusion energy, we are developing a laser-diode-pumped zig-zag Nd:glass slab laser amplifier system HALNA 10 (High Average-power Laser for Nuclear-fusion Application) which can generate an output of 10 J per pulse at 1053 nm in 10 Hz operation. The water-cooled zig-zag Nd:glass slab is pumped from both sides by 803-nm AlGaAs laser-diode(LD) module; each LD module has an emitting area of 420 mm x 10 mm and two LD modules generated in total 218 (max.) kW peak power with 2.6kW/cm 2 peak intensity at 10 Hz repetition rate. We have obtained in a preliminary experiment a 8.5 J output energy at 0.5 Hz with beam quality of 2 times diffraction limited far-field pattern, which nearly confirmed our conceptual design. (author)

  20. Wireless ZigBee home automation system

    Science.gov (United States)

    Craciunescu, Razvan; Halunga, Simona; Fratu, Octavian

    2015-02-01

    The home automation system concept existed for many years but in the last decade, due to the rapid development of sensors and wireless technologies, a large number of various such "intelligent homes" have been developed. The purpose of the present paper is to demonstrate the flexibility, reliability and affordability of home automation projects, based on a simple and affordable implementation. A wireless sensing and control system have been developed and tested, having a number of basic functionalities such as switching on/off the light according to ambient lighting and turning on/off the central heating. The system has been built around low power microcontrollers and ZigBee modems for wireless communication, using a set of Vishay 640 thermistor sensors for temperature measurements and Vishay LDR07 photo-resistor for humidity measurements. A trigger is activated when the temperature or light measurements are above/below a given threshold and a command is transmitted to the central unit through the ZigBee radio module. All the data processing is performed by a low power microcontroller both at the sensing device and at the control unit.

  1. Low-temperature spin transport in a S = 1 one-dimensional antiferromagnet

    International Nuclear Information System (INIS)

    Pires, A S T; Lima, L S

    2009-01-01

    We study spin transport in the insulating antiferromagnet with S = 1 in one dimension. The spin conductivity is calculated, at zero temperature, using a modified spin wave theory and the Kubo formalism, within the ladder approximation. Two-magnon processes provide the dominant contribution to the spin conductivity. At finite temperature, free magnons are activated, and turn the system into a perfect spin conductor, i.e., the spin conductivity has a Drude form with infinite scattering time.

  2. Resonance – Journal of Science Education | Indian Academy of ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education. Syed R Hussaini. Articles written in Resonance – Journal of Science Education. Volume 15 Issue 4 April 2010 pp 351-354 Classroom. Interconversion of Fischer and Zig-Zag Projections - Learning Stereochemistry with the Help of Hands · Syed R Hussaini.

  3. Spin-orbit coupling, electron transport and pairing instabilities in two-dimensional square structures

    Energy Technology Data Exchange (ETDEWEB)

    Kocharian, Armen N. [Department of Physics, California State University, Los Angeles, CA 90032 (United States); Fernando, Gayanath W.; Fang, Kun [Department of Physics, University of Connecticut, Storrs, Connecticut 06269 (United States); Palandage, Kalum [Department of Physics, Trinity College, Hartford, Connecticut 06106 (United States); Balatsky, Alexander V. [AlbaNova University Center Nordita, SE-106 91 Stockholm (Sweden)

    2016-05-15

    Rashba spin-orbit effects and electron correlations in the two-dimensional cylindrical lattices of square geometries are assessed using mesoscopic two-, three- and four-leg ladder structures. Here the electron transport properties are systematically calculated by including the spin-orbit coupling in tight binding and Hubbard models threaded by a magnetic flux. These results highlight important aspects of possible symmetry breaking mechanisms in square ladder geometries driven by the combined effect of a magnetic gauge field spin-orbit interaction and temperature. The observed persistent current, spin and charge polarizations in the presence of spin-orbit coupling are driven by separation of electron and hole charges and opposite spins in real-space. The modeled spin-flip processes on the pairing mechanism induced by the spin-orbit coupling in assembled nanostructures (as arrays of clusters) engineered in various two-dimensional multi-leg structures provide an ideal playground for understanding spatial charge and spin density inhomogeneities leading to electron pairing and spontaneous phase separation instabilities in unconventional superconductors. Such studies also fall under the scope of current challenging problems in superconductivity and magnetism, topological insulators and spin dependent transport associated with numerous interfaces and heterostructures.

  4. Spin-orbit coupling, electron transport and pairing instabilities in two-dimensional square structures

    Directory of Open Access Journals (Sweden)

    Armen N. Kocharian

    2016-05-01

    Full Text Available Rashba spin-orbit effects and electron correlations in the two-dimensional cylindrical lattices of square geometries are assessed using mesoscopic two-, three- and four-leg ladder structures. Here the electron transport properties are systematically calculated by including the spin-orbit coupling in tight binding and Hubbard models threaded by a magnetic flux. These results highlight important aspects of possible symmetry breaking mechanisms in square ladder geometries driven by the combined effect of a magnetic gauge field spin-orbit interaction and temperature. The observed persistent current, spin and charge polarizations in the presence of spin-orbit coupling are driven by separation of electron and hole charges and opposite spins in real-space. The modeled spin-flip processes on the pairing mechanism induced by the spin-orbit coupling in assembled nanostructures (as arrays of clusters engineered in various two-dimensional multi-leg structures provide an ideal playground for understanding spatial charge and spin density inhomogeneities leading to electron pairing and spontaneous phase separation instabilities in unconventional superconductors. Such studies also fall under the scope of current challenging problems in superconductivity and magnetism, topological insulators and spin dependent transport associated with numerous interfaces and heterostructures.

  5. Network Signaling Channel for Improving ZigBee Performance in Dynamic Cluster-Tree Networks

    Directory of Open Access Journals (Sweden)

    D. Hämäläinen

    2008-03-01

    Full Text Available ZigBee is one of the most potential standardized technologies for wireless sensor networks (WSNs. Yet, sufficient energy-efficiency for the lowest power WSNs is achieved only in rather static networks. This severely limits the applicability of ZigBee in outdoor and mobile applications, where operation environment is harsh and link failures are common. This paper proposes a network channel beaconing (NCB algorithm for improving ZigBee performance in dynamic cluster-tree networks. NCB reduces the energy consumption of passive scans by dedicating one frequency channel for network beacon transmissions and by energy optimizing their transmission rate. According to an energy analysis, the power consumption of network maintenance operations reduces by 70%–76% in dynamic networks. In static networks, energy overhead is negligible. Moreover, the service time for data routing increases up to 37%. The performance of NCB is validated by ns-2 simulations. NCB can be implemented as an extension on MAC and NWK layers and it is fully compatible with ZigBee.

  6. Fault Tolerance in ZigBee Wireless Sensor Networks

    Science.gov (United States)

    Alena, Richard; Gilstrap, Ray; Baldwin, Jarren; Stone, Thom; Wilson, Pete

    2011-01-01

    Wireless sensor networks (WSN) based on the IEEE 802.15.4 Personal Area Network standard are finding increasing use in the home automation and emerging smart energy markets. The network and application layers, based on the ZigBee 2007 PRO Standard, provide a convenient framework for component-based software that supports customer solutions from multiple vendors. This technology is supported by System-on-a-Chip solutions, resulting in extremely small and low-power nodes. The Wireless Connections in Space Project addresses the aerospace flight domain for both flight-critical and non-critical avionics. WSNs provide the inherent fault tolerance required for aerospace applications utilizing such technology. The team from Ames Research Center has developed techniques for assessing the fault tolerance of ZigBee WSNs challenged by radio frequency (RF) interference or WSN node failure.

  7. Design of remote car anti-theft system based on ZigBee

    Science.gov (United States)

    Fang, Hong; Yan, GangFeng; Li, Hong Lian

    2015-12-01

    A set of remote car anti-theft system based on ZigBee and GPRS with ARM11 built-in chip S3C6410 as the controller is designed. This system can detect the alarm information of the car with vibration sensor, pyroelectric sensor and infrared sensor. When the sensor detects any alarm signal, the ZigBee node in sleep will be awakened and then directly send the alarm signal to the microcontroller chip S3C6410 in the control room of the parking lot through ZigBee wireless transceiver module. After S3C6410 processes and analyzes the alarm signal, when any two sensors of the three collect the alarm signal, the LCD will display and generate an alarm and meanwhile it will send the alarm signal to the phone of the user in a wireless manner through the form of short message through GPRS module. Thus, the wireless remote monitoring of the system is realized.

  8. Study of apical oxygen atoms in a spin-ladder cuprate compound by X-ray absorption spectroscopy near the Cu K edge

    Energy Technology Data Exchange (ETDEWEB)

    Hatterer, C.J.; Eustache, B.; Collin, L.; Beuran, C.F.; Partiot, C.; Germain, P.; Xu, X.Z.; Lagues, M. [CNRS, Paris (France). Surfaces et Supraconducteurs; Michalowicz, A. [Laboratoire de Physique des Milieux Desordonnes, Universite Paris XII Val-de-Marne, 61 avenue du general de Gaulle, 94010, Creteil Cedex (France)]|[LURE, Universite Paris Sud, 91405, Orsay Cedex (France); Moscovici, J. [Laboratoire de Physique des Milieux Desordonnes, Universite Paris XII Val-de-Marne, 61 avenue du general de Gaulle, 94010, Creteil Cedex (France); Deville Cavellin, C. [CNRS, Paris (France). Surfaces et Supraconducteurs]|[Laboratoire d`Electronique, Universite Paris XII Val-de-Marne, 61 av. du general de Gaulle, 94010, Creteil Cedex (France); Traverse, A. [LURE, Universite Paris Sud, 91405, Orsay Cedex (France)

    1997-04-01

    The structure of high-T{sub c} superconducting cuprate compounds is based on CuO{sub 2} planes alternating with blocks that behave as charge reservoirs. The apical oxygen atoms which belong to these reservoirs are suspected to play a role in the mechanism of superconductivity. It thus seems necessary to measure the amount of apical oxygen atoms in various compounds, as a function of the superconducting properties. Polarisation dependent X-ray absorption spectroscopy (XAS) measurements were performed near the Cu K-edge on three types of phases. We collected information about the neighbourhood of the copper atom in the cuprate planes and in the direction perpendicular to these planes. Two of these phases have well known structures: Bi2212 in which copper atoms are on a pyramidal site and infinite layer phase, a square planar cuprate without apical oxygen. We used the obtained results as reference data to study a new copper-rich phase related to the spin-ladder series. (orig.)

  9. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    The crystal structure analysis reveals a one-dimensional extended chain in which the Anderson type heteropolyanion, acting as the building unit, is linked by rare earth metal ions in a zig-zag fashion. In the crystal structure, all types of oxygens of the heteropolyanion, lattice waters, lanthanum coordinated waters are ...

  10. Are N-methyl groups of Tetramethylurea (TMU) Hydrophobic? A ...

    Indian Academy of Sciences (India)

    of three dimensional tetrahedral H-bond network to two dimensional zig-zag chain-like structure often found in alcohols. A comparison to ... All these results indicate hydrophobic interaction-induced aggregation of TMU in dilute aqueous solutions which .... off by gently blowing hot air around the outer surface of the cuvette.

  11. Ladder variational autoencoders

    DEFF Research Database (Denmark)

    Sønderby, Casper Kaae; Raiko, Tapani; Maaløe, Lars

    2016-01-01

    Variational autoencoders are powerful models for unsupervised learning. However deep models with several layers of dependent stochastic variables are difficult to train which limits the improvements obtained using these highly expressive models. We propose a new inference model, the Ladder...... Variational Autoencoder, that recursively corrects the generative distribution by a data dependent approximate likelihood in a process resembling the recently proposed Ladder Network. We show that this model provides state of the art predictive log-likelihood and tighter log-likelihood lower bound compared...

  12. Ladder Variational Autoencoder

    DEFF Research Database (Denmark)

    Sønderby, Casper Kaae; Raiko, Tapani; Maaløe, Lars

    2016-01-01

    Variational autoencoders are powerful models for unsupervised learning. However deep models with several layers of dependent stochastic variables are difficult to train which limits the improvements obtained using these highly expressive models. We propose a new inference model, the Ladder...... Variational Autoencoder, that recursively corrects the generative distribution by a data dependent approximate likelihood in a process resembling the recently proposed Ladder Network. We show that this model provides state of the art predictive log-likelihood and tighter log-likelihood lower bound compared...

  13. Two-leg ladder systems with dipole–dipole Fermion interactions

    Science.gov (United States)

    Mosadeq, Hamid; Asgari, Reza

    2018-05-01

    The ground-state phase diagram of a two-leg fermionic dipolar ladder with inter-site interactions is studied using density matrix renormalization group (DMRG) techniques. We use a state-of-the-art implementation of the DMRG algorithm and finite size scaling to simulate large system sizes with high accuracy. We also consider two different model systems and explore stable phases in half and quarter filling factors. We find that in the half filling, the charge and spin gaps emerge in a finite value of the dipole–dipole and on-site interactions. In the quarter filling case, s-wave superconducting state, charge density wave, homogenous insulating and phase separation phases occur depend on the interaction values. Moreover, in the dipole–dipole interaction, the D-Mott phase emerges when the hopping terms along the chain and rung are the same, whereas, this phase has been only proposed for the anisotropic Hubbard model. In the half filling case, on the other hand, there is either charge-density wave or charged Mott order phase depends on the orientation of the dipole moments of the particles with respect to the ladder geometry.

  14. De optimale sportafstand voor de ladder van de glazenwasser

    NARCIS (Netherlands)

    Reijneveld, C.N.; Looze, M.P. de; Hoozemans, M.J.M.; Grinten, M.P. van der; Korte, E.M. de; Kingma, I.

    2002-01-01

    Voor de glazenwasser die werkt met staande ladder, is een goede ladder zeer belangrijk. Hij loopt en werkt op en verplaatst de ladder veelvuldig. Er is veel discussie over ladders en de optimale sportafstand bij staande ladders. De meeste glazenwassers geven de voorkeur aan een sportafstand van 35

  15. ZIL: An Energy-Efficient Indoor Localization System Using ZigBee Radio to Detect WiFi Fingerprints

    OpenAIRE

    Niu, Jianwei; Wang, Bowei; Shu, Lei; Duong, Trung Q.; Chen, Yuanfang

    2015-01-01

    In existing WiFi-based localization methods, smart mobile devices consume quite a lot of power as WiFi interfaces need to be used for frequent AP scanning during the localization process. In this work, we design an energy-efficient indoor localization system called ZigBee assisted indoor localization (ZIL) based on WiFi fingerprints via ZigBee interference signatures. ZIL uses ZigBee interfaces to collect mixed WiFi signals, which include non-periodic WiFi data and periodic beacon signals. Ho...

  16. Structure and function of the spermathecal complex in the ...

    Indian Academy of Sciences (India)

    Unknown

    sandfly are compared with those of other insect species. ... Psychodidae): I. Ultrastructure and histology; J. Biosci. ... of P. papatasi, which was maintained at 26°C and 75% .... bular, 1 µm wide structure runs in a zig-zag course from ... Figure 3. (A) SEM of the isolated spermathecal complex. The spermathecae (SP) are.

  17. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    In keeping with experimental data, we find the presence of ordered adsorbed layers both at single monolayer coverage and when the adsorbed layer coexists with ... The zig-zag backbone planes of all the alkane molecules lie parallel to the graphite surface at the multilayer coverage, while a few molecules are observed to ...

  18. Design of Smart Home Control System Based on ARM and ZigBee%基于ARM和ZigBee的智能家居控制系统设计

    Institute of Scientific and Technical Information of China (English)

    黄国伟; 彭玲; 林伟腾

    2014-01-01

    为实现家居设备远程控制智能化,提出一种基于ARM、ZigBee和GPRS技术的智能家居控制系统。系统以ARM9处理器S3C2440为控制核心,利用ZigBee技术组建无线传感网络,实现家庭内部各种设备的无线连接和信息采集功能。通过在ARM上移植BOA Web服务器,同时利用 GPRS技术接入移动通信网络,实现用户利用远端PC和手机远程监控家居环境设备的功能。测试结果表明,系统达到设计要求。%In order to achieve the remote monitoring and control household ,designs a smart home control system based on ARM, ZigBee and GPRS technologies. The system uses ARM920T embedded processor S3C2440 as the control center, uses ZigBee wireless sensor networks to collect and transmit various household data, uses BOA Web servicer to build on ARM platform to achieve the landing Web page function, uses GPRS technology to access mobile telecommunication network, so as to achieve the remote control function by PC and mobile of users. The test result shows that the system conforms to the design requirements.

  19. An algorithmic metatheorem for directed treewidth

    Czech Academy of Sciences Publication Activity Database

    de Oliveira Oliveira, Mateus

    2016-01-01

    Roč. 204, May (2016), s. 49-76 ISSN 0166-218X EU Projects: European Commission(XE) 339691 - FEALORA Institutional support: RVO:67985840 Keywords : combinatorial slice theory * directed treewidth * tree-zig-zag number Subject RIV: BA - General Mathematics Impact factor: 0.956, year: 2016 http://www.sciencedirect.com/science/article/pii/S0166218X15005077

  20. Pramana – Journal of Physics | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    pp 1-2. General editorial on publication ethics .... The effect of laser beam size in a zig-zag collimator on transverse cooling of a krypton atomic beam ... Nonadiabatic corrections to a quantum dot quantum computer working in adiabatic limit ... The time of operation of an adiabatic quantum computer must be less than the ...

  1. Some Inheritance Properties for Complementary Basic Matrices

    Czech Academy of Sciences Publication Activity Database

    Fiedler, Miroslav; Hall, F.J.

    2010-01-01

    Roč. 433, 11-12 (2010), s. 2060-2069 ISSN 0024-3795 Institutional research plan: CEZ:AV0Z10300504 Keywords : subdiagonal rank * zig-zag shape * factorization * CB-matrix * sign pattern matrix * sign nonsingular matrix * companion matrix * P-matrix * totally nonnegative matrix * oscillatory matrix Subject RIV: BA - General Mathematics Impact factor: 1.005, year: 2010

  2. 29 CFR 1917.118 - Fixed ladders.

    Science.gov (United States)

    2010-07-01

    ... tubular scaffold framing; and (4) Ladders used only for fire-fighting or emergency purposes. (b... of equipment. (3) Ladder safety device means a support system limiting an employee's drop or fall...

  3. STXM-XANES Analysis of Organic Matter in Dark Clasts and Halite Crystals in Zag and Monahans Meteorites

    Science.gov (United States)

    Kebukawa, Y.; Zolensky, M. E.; Fries, M.; Nakato, A.; Kilcoyne, A. L. D.; Takeichi, Y.; Suga, H.; Miyamoto, C.; Rahman, Z.; Kobayashi, K.; hide

    2016-01-01

    Zag and Monahans meteorites (H5) contains xenolithic dark clasts and halite (NaCl) crystals [e.g., 1]. The proposed source of the H chondrites is asteroid 6 Hebe [2]. The modern orbits of 1 Ceres and 6 Hebe essentially cross, with aphelion/perihelion of Ceres and Hebe of 2.99/2.55 and 2.91/1.94 AU (Astronomical Units), respectively. Therefore, Ceres might be the source of the clasts and halite in Zag and Monahans meteorites. Recent results from NASA's Dawn mission shows that bright spots in Ceres's crater may be hydrated magnesium sulfate with some water ice, and an average global surface contains ammoniated phyllosilicates that is likely of outer Solar System origin. One dark clast and all halite crystals in Zag and Monahans meteorites contain carbon-rich particles. We report organic analyses of these carbon-rich particles using carbon, nitrogen, and oxygen X-ray absorption near edge structure (C-, N-, and O-XANES), in order to constrain the origin of the clast and halite crystals.

  4. Some problems associated with the analysis and interpretation of mixed carbonate and quartz beach sands, illustrated by examples from North-West Ireland

    Science.gov (United States)

    Carter, R. W. G.

    1982-09-01

    Mixes of carbonate and quartz sands, which are commonly encountered in Recent coastal sediments, require careful analysis if they are to be correctly interpreted. Grain-size data fall into multimodal or segmented zig-zag distributions which may require some kind of component separation if they are to be summarised by conventional statistics, and before they can be assigned to a particular hydrodynamic depositional process or environment. Unfortunately, separation techniques are only spasmodically applied, usually without due regard to the consequences. Such artificially filtered or truncated distributions are of little subsequent use. Using a range of samples from two beaches in NW Ireland, where carbonate proportions range from nearly zero to over sixty percent, the interrelationships of the two dominant components were examined. Where only a small carbonate proportion is incorporated into a large quartz one, predictable modifications of the size-curve are apparent. However, the components are more independent if mixtures are near equal. The occurrence of a number of distinctive combinations of simple straight lines and complex zig-zag curves probably reflects the relatively dynamic nature of the carbonate fraction.

  5. Perspective on rainbow-ladder truncation

    International Nuclear Information System (INIS)

    Eichmann, G.; Alkofer, R.; Krassnigg, A.; Cloeet, I. C.; Roberts, C. D.

    2008-01-01

    Prima facie the systematic implementation of corrections to the rainbow-ladder truncation of QCD's Dyson-Schwinger equations will uniformly reduce in magnitude those calculated mass-dimensioned results for pseudoscalar and vector meson properties that are not tightly constrained by symmetries. The aim and interpretation of studies employing rainbow-ladder truncation are reconsidered in this light

  6. Evolution of the low-energy excitation spectrum from the pure Hubbard ladder to the SO(5) ladder: A numerical study

    International Nuclear Information System (INIS)

    Duffy, D.; Haas, S.; Kim, E.

    1998-01-01

    The Hubbard Hamiltonian on a two-leg ladder is studied numerically using quantum Monte Carlo and exact diagonalization techniques. A rung interaction, V, is turned on such that the resulting model has an exact SO(5) symmetry when V=-U. The evolution of the low-energy excitation spectrum is presented from the pure Hubbard ladder to the SO(5) ladder. It is shown that the low-energy excitations in the pure Hubbard ladder have an approximate SO(5) symmetry. copyright 1998 The American Physical Society

  7. Syntheses, structures and properties of two coordination polymers of ...

    Indian Academy of Sciences (India)

    Dipu Sutradhar

    2017-11-10

    Nov 10, 2017 ... condensation reaction of ap and bp some degradation occurs in presence of the metal ion to afford an in situ generated bidentate ... end-to-end (EE) thiocyanates to form a non-ending linear 1D zig-zag chain. Further, in crystalline state ... S hydrogen bond interaction promoting 2D sheet structure. Thermally ...

  8. Pramana – Journal of Physics | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    The effect of size of a cooling laser beam in a zig-zag atomic beam collimator on transverse cooling of a krypton atomic beam is investigated. The simulation results show that discreteness in the interaction between the cooling laser beam and atomic beam, arising due to finite size and incidence angle of the cooling laser ...

  9. The crystal structure of ferdowsiite Ag8Sb4(As,Sb)4S16 and its relations to other ABX2 (A=Ag; B=As,Sb,Bi; X=S,Se) structures

    DEFF Research Database (Denmark)

    Makovicky, Emil; Topa, Dan

    2014-01-01

    arsenic. The crystal structure of ferdowsiite is a superstructure of a PbS like motif. The {100} planes of the PbS-like substructure are the (105̅), (301) and (010) planes in terms of the ferdowsiite lattice. The structure contains zig-zag chains of Sb1 connected via short Sb-S bonds and flanked by (Sb...

  10. Amino Acids in the Asteroidal Water-Bearing Salt Crystals Hosted in the Zag Meteorite

    Science.gov (United States)

    Chan, Q. H. S.; Zolensky, M. E.; Burton, A. S.; Locke, D. R.

    2016-01-01

    Solid evidence of liquid water in primitive meteorites is given by the ordinary chondrites H5 Monahans (1998) and H3-6 Zag. Aqueous fluid inclusion-bearing halite (NaCl) crystals were shown to be common in Zag. These striking blue/purple crystals (Figure 1), which gained the coloration from electron-trapping in the Cl-vacancies through exposure to ionizing radiation, were determined to be over 4.0-4.7 billion years old by I-Xe dating. The halite grains are present as discrete grains within an H-chondrite matrix with no evidence for aqueous alteration that indicates a xenogenic source, possibly ancient cryovolcanism. They were proposed to be formed from the cryovolcanic plumes on icy C-type asteroids (possibly Ceres), and were transferred and incorporated into the H chondrite parent asteroid following the eruption event(s). A unique aspect of these halites is that they contain abundant solid inclusions hosted within the halites alongside the water inclusions. The solid inclusions were suggested to be entrained within the fluid erupted from the cryovolcanic event(s), and were shown to be comprised of abundant organics. Spectrofluorometric study and Raman imaging of the halites have identified macromolecular carbon and aliphatic carbon compounds. In order to investigate the type of organics present in Zag and in particular within the fluid-bearing halites, we studied for the first time the amino acid contents of a selected mineral (halite) phase in a meteorite sample.

  11. Passage and behaviour of cultured Lake Sturgeon in a prototype side-baffle fish ladder: I. Ladder hydraulics and fish ascent

    Science.gov (United States)

    Kynard, B.; Pugh, D.; Parker, T.

    2011-01-01

    Research and development of a fish ladder for sturgeons requires understanding ladder hydraulics and sturgeon behaviour in the ladder to insure the ladder is safe and provides effective passage. After years of research and development, we designed and constructed a full-scale prototype side-baffle ladder inside a spiral flume (38.3m long??1m wide??1m high) on a 6% (1:16.5) slope with a 1.92-m rise in elevation (bottom to top) to test use by sturgeons. Twenty-eight triangular side baffles, each extending part way across the flume, alternated from inside wall to outside wall down the ladder creating two major flow habitats: a continuous, sinusoidal flow down the ladder through the vertical openings of side-baffles and an eddy below each side baffle. Ascent and behaviour was observed on 22 cultured Lake Sturgeon=LS (Acipenser fulvescens) repeatedly tested in groups as juveniles (as small as 105.1cm TL, mean) or as adults (mean TL, 118cm) during four periods (fall 2002 and 2003; spring 2003 and 2007). Percent of juveniles entering the ladder that ascended to the top was greater in spring (72.7%) than in fall (40.9-45.5%) and 90.9% of 11 adults, which ascended as juveniles, ascended to the top. Six LS (27.3%) never swam to the top and seven (31.8%) swam to the top in all tests, indicating great variability among individuals for ascent drive. Some LS swam directly to the top in <1min, but most rested in an eddy during ascent. Juveniles swimming through outside wall baffle slots (mean velocity, 1.2ms-1) swam at 1.8-2.2body lengthss-1 and 3.2-3.3tail beatss-1, either at or approaching prolonged swimming speed. The side-baffle ladder was stream-like and provided key factors for a sturgeon ladder: a continuous flow and no full cross-channel walls, abundant eddies for resting, an acceptable water depth, and a water velocity fish could ascend swimming 2bls-1. A side-baffle ladder passes LS and other moderate-swimming fishes. ?? 2011 Blackwell Verlag, Berlin.

  12. Career ladder program for registered nurses in ambulatory care.

    Science.gov (United States)

    Nelson, Joan; Sassaman, Becky; Phillips, Alison

    2008-01-01

    RN ladder programs are designed to inspire and reward clinical excellence. Kaiser Permanente Colorado's (KPCO) career ladder program emerged as a result of a labor-management partnership. Career ladder point assignments are reflective of the organization's priorities and values. KPCO's career ladder point tool awards RNs for formal and continuing education, professional presentations, organizational experience and experience as an RN, certifications and active professional memberships, leadership activities, research and publications, and nursing-related volunteer work. Participation in the RN career ladder requires that the nurse achieve a self-determined, manager-approved, measurable goal that will improve patient care. Career ladder nurses at KPCO were significantly more involved in leadership and interdisciplinary activities, quality improvement projects, and preceptorship.

  13. FPGA implementation of a ZigBee wireless network control interface to transmit biomedical signals

    International Nuclear Information System (INIS)

    López, M A Gómez; Goy, C B; Bolognini, P C; Herrera, M C

    2011-01-01

    In recent years, cardiac hemodynamic monitors have incorporated new technologies based on wireless sensor networks which can implement different types of communication protocols. More precisely, a digital conductance catheter system recently developed adds a wireless ZigBee module (IEEE 802.15.4 standards) to transmit cardiac signals (ECG, intraventricular pressure and volume) which would allow the physicians to evaluate the patient's cardiac status in a noninvasively way. The aim of this paper is to describe a control interface, implemented in a FPGA device, to manage a ZigBee wireless network. ZigBee technology is used due to its excellent performance including simplicity, low-power consumption, short-range transmission and low cost. FPGA internal memory stores 8-bit signals with which the control interface prepares the information packets. These data were send to the ZigBee END DEVICE module that receives and transmits wirelessly to the external COORDINATOR module. Using an USB port, the COORDINATOR sends the signals to a personal computer for displaying. Each functional block of control interface was assessed by means of temporal diagrams. Three biological signals, organized in packets and converted to RS232 serial protocol, were successfully transmitted and displayed in a PC screen. For this purpose, a custom-made graphical software was designed using LabView.

  14. FPGA implementation of a ZigBee wireless network control interface to transmit biomedical signals

    Science.gov (United States)

    Gómez López, M. A.; Goy, C. B.; Bolognini, P. C.; Herrera, M. C.

    2011-12-01

    In recent years, cardiac hemodynamic monitors have incorporated new technologies based on wireless sensor networks which can implement different types of communication protocols. More precisely, a digital conductance catheter system recently developed adds a wireless ZigBee module (IEEE 802.15.4 standards) to transmit cardiac signals (ECG, intraventricular pressure and volume) which would allow the physicians to evaluate the patient's cardiac status in a noninvasively way. The aim of this paper is to describe a control interface, implemented in a FPGA device, to manage a ZigBee wireless network. ZigBee technology is used due to its excellent performance including simplicity, low-power consumption, short-range transmission and low cost. FPGA internal memory stores 8-bit signals with which the control interface prepares the information packets. These data were send to the ZigBee END DEVICE module that receives and transmits wirelessly to the external COORDINATOR module. Using an USB port, the COORDINATOR sends the signals to a personal computer for displaying. Each functional block of control interface was assessed by means of temporal diagrams. Three biological signals, organized in packets and converted to RS232 serial protocol, were sucessfully transmitted and displayed in a PC screen. For this purpose, a custom-made graphical software was designed using LabView.

  15. Application of ZigBee technology in the X fluorescence analyzer

    International Nuclear Information System (INIS)

    Wang Haibin; Yang Jian; Cao Bihua; Zhao Xiang

    2010-01-01

    In order to ensure safe and convenient measurement of nuclear radiation, a ZigBee- technology- based X- fluorescence analyzer is developed to be used in laboratories to make quantitative and qualitative analysis of radioactive samples. (authors)

  16. Edge currents in frustrated Josephson junction ladders

    Science.gov (United States)

    Marques, A. M.; Santos, F. D. R.; Dias, R. G.

    2016-09-01

    We present a numerical study of quasi-1D frustrated Josephson junction ladders with diagonal couplings and open boundary conditions, in the large capacitance limit. We derive a correspondence between the energy of this Josephson junction ladder and the expectation value of the Hamiltonian of an analogous tight-binding model, and show how the overall superconducting state of the chain is equivalent to the minimum energy state of the tight-binding model in the subspace of one-particle states with uniform density. To satisfy the constraint of uniform density, the superconducting state of the ladder is written as a linear combination of the allowed k-states of the tight-binding model with open boundaries. Above a critical value of the parameter t (ratio between the intra-rung and inter-rung Josephson couplings) the ladder spontaneously develops currents at the edges, which spread to the bulk as t is increased until complete coverage is reached. Above a certain value of t, which varies with ladder size (t = 1 for an infinite-sized ladder), the edge currents are destroyed. The value t = 1 corresponds, in the tight-binding model, to the opening of a gap between two bands. We argue that the disappearance of the edge currents with this gap opening is not coincidental, and that this points to a topological origin for these edge current states.

  17. Determination of trace elements in a cigarette paper by neutron activation analysis

    International Nuclear Information System (INIS)

    Abedinzadeh, Z.; Khalkhali, Zh.; Razeghi, M.; Parsa, B.

    The concentration of 19 trace elements in a cigarette paper (Zig-Zag Paper Company, France) which is used in making different brands of Iranian cigarettes, has been measured by neutron activation analysis, employing a high-resolution Ge(Li) detector. They include Na, K, Ca, Sc, Cr, Mn, Fe, Co, Zn, Br, Sr, Sb, Ba, Ce, Eu, Gd, Au, Hg, and Th. (author)

  18. Transport properties of a ladder with two random dimer chains

    International Nuclear Information System (INIS)

    Hu Dong-Sheng; Zhu Chen-Ping; Zhang Yong-Mei

    2011-01-01

    We investigate the transport properties of a ladder with two random dimer (RD) chains. It is found that there are two extended states in the ladder with identical RD chains and a critical state regarded as an extended state in the ladder with pairing RD chains. Such a critical state is caused by the chiral symmetry. The ladder with identical RD chains can be decoupled into two isolated RD chains and the ladder with pairing RD chains can not. The analytic expressions of the extended states are presented for the ladder with identical RD chains. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  19. Modeling of current consumption in 802.15.4/ZigBee sensor motes.

    Science.gov (United States)

    Casilari, Eduardo; Cano-García, Jose M; Campos-Garrido, Gonzalo

    2010-01-01

    Battery consumption is a key aspect in the performance of wireless sensor networks. One of the most promising technologies for this type of networks is 802.15.4/ZigBee. This paper presents an empirical characterization of battery consumption in commercial 802.15.4/ZigBee motes. This characterization is based on the measurement of the current that is drained from the power source under different 802.15.4 communication operations. The measurements permit the definition of an analytical model to predict the maximum, minimum and mean expected battery lifetime of a sensor networking application as a function of the sensor duty cycle and the size of the sensed data.

  20. Short-distance behavior of the Bethe--Salpeter wave function in the ladder approximation

    International Nuclear Information System (INIS)

    Guth, A.H.; Soper, D.E.

    1975-01-01

    We investigate the short-distance behavior of the (Wick-rotated) Bethe--Salpeter wave function for the two spin-1/2 quarks bound by the exchange of a massive vector meson. We use the ladder-model kernel, which has the same p -4 scaling behavior as the true kernel in a theory with a fixed point of the renormalization group at g not equal to 0. For a bound state with the quantum numbers of the pion, the leading asymptotic behavior is chi (q/sup μ/) approx. cq/sup -4 + epsilon(g)/γ 5 , where epsilon (g) =1- (1-g 2 /π 2 ) 1 / 2 . Our method also provides the full asymptotic series, although it should be noted that the nonleading terms will depend on the nonleading behavior of the ladder-model kernel. A general term has the form cq - /sup a/(lnq)/sup n/phi (q/sup μ/), where c is an unknown constant, a may be integral or nonintegral, n is an integer, and phi (q/sup μ/) is a representation function of the rotation group in four dimensions

  1. The Relaxation of Vicinal (001) with ZigZag [110] Steps

    Science.gov (United States)

    Hawkins, Micah; Hamouda, Ajmi Bh; González-Cabrera, Diego Luis; Einstein, Theodore L.

    2012-02-01

    This talk presents a kinetic Monte Carlo study of the relaxation dynamics of [110] steps on a vicinal (001) simple cubic surface. This system is interesting because [110] steps have different elementary excitation energetics and favor step diffusion more than close-packed [100] steps. In this talk we show how this leads to relaxation dynamics showing greater fluctuations on a shorter time scale for [110] steps as well as 2-bond breaking processes being rate determining in contrast to 3-bond breaking processes for [100] steps. The existence of a steady state is shown via the convergence of terrace width distributions at times much longer than the relaxation time. In this time regime excellent fits to the modified generalized Wigner distribution (as well as to the Berry-Robnik model when steps can overlap) were obtained. Also, step-position correlation function data show diffusion-limited increase for small distances along the step as well as greater average step displacement for zigzag steps compared to straight steps for somewhat longer distances along the step. Work supported by NSF-MRSEC Grant DMR 05-20471 as well as a DOE-CMCSN Grant.

  2. Converting Chair-like Transition States into Zig-Zag Projections A ...

    Indian Academy of Sciences (India)

    IAS Admin

    From early instruction, chemistry students learn that cylcohexane exists mainly .... GSR. Br. CBP. Ph. Br. Figure 2. The processes of. CBP and GSR. Z enolates provide ... taking upper level organic chemistry courses such as Physical. Organic ...

  3. Modeling the Sliding/Falling Ladder Paradox

    Science.gov (United States)

    Fox, William P.; Fox, James B.

    2003-01-01

    Recently we were presented with an interesting twist to the sliding ladder problem viewed in the related rates section of most calculus textbooks. Our problem concerning a sliding ladder that eventually hits the ground. At first, those attempting this problem fell into the calculus trap using only related rates. Previous work for this problem…

  4. 5 CFR 335.104 - Eligibility for career ladder promotion.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Eligibility for career ladder promotion... REGULATIONS PROMOTION AND INTERNAL PLACEMENT General Provisions § 335.104 Eligibility for career ladder promotion. No employee shall receive a career ladder promotion unless his or her current rating of record...

  5. Modeling of Current Consumption in 802.15.4/ZigBee Sensor Motes

    Directory of Open Access Journals (Sweden)

    Eduardo Casilari

    2010-06-01

    Full Text Available Battery consumption is a key aspect in the performance of wireless sensor networks. One of the most promising technologies for this type of networks is 802.15.4/ZigBee. This paper presents an empirical characterization of battery consumption in commercial 802.15.4/ZigBee motes. This characterization is based on the measurement of the current that is drained from the power source under different 802.15.4 communication operations. The measurements permit the definition of an analytical model to predict the maximum, minimum and mean expected battery lifetime of a sensor networking application as a function of the sensor duty cycle and the size of the sensed data.

  6. PM2.5 monitoring system based on ZigBee wireless sensor network

    Science.gov (United States)

    Lin, Lukai; Li, Xiangshun; Gu, Weiying

    2017-06-01

    In the view of the haze problem, aiming at improving the deficiency of the traditional PM2.5 monitoring methods, such as the insufficient real-time monitoring, limited transmission distance, high cost and the difficulty to maintain, the atmosphere PM2.5 monitoring system based on ZigBee technology is designed. The system combines the advantages of ZigBee’s low cost, low power consumption, high reliability and GPRS/Internet’s capability of remote transmission of data. Furthermore, it adopts TI’s Z-Stack protocol stack, and selects CC2530 chip and TI’s MSP430 microcontroller as the core, which establishes the air pollution monitoring network that is helpful for the early prediction of major air pollution disasters.

  7. Helicity eigenstates of a relativistic spin-0 and spin-1/2 constituent bound by minimal electrodynamics: Zero orbital angular momentum, zero four-momentum solutions

    International Nuclear Information System (INIS)

    Mainland, G.B.

    1988-01-01

    Zero four-momentum, helicity eigenstates of the Bethe--Salpeter equation are found for a composite system consisting of a charged, spin-0 constituent and a charged, spin- 1/2 constituent bound by minimal electrodynamics. The form of the Bethe--Salpeter equation used to describe the bound state includes the contributions from both single photon exchange (ladder approximation) and the ''seagull'' diagram. Attention is restricted to zero orbital angular momentum states since these appear to be the most interesting physically

  8. The Static Ladder Problem with Two Sources of Friction

    Science.gov (United States)

    Bennett, Jonathan; Mauney, Alex

    2011-01-01

    The problem of a ladder leaning against a wall in static equilibrium is a classic example encountered in introductory mechanics texts. Most discussions of this problem assume that the static frictional force between the ladder and wall can be ignored. A few authors consider the case where the static friction coefficients between ladder/wall…

  9. Quantifying Ladder Fuels: A New Approach Using LiDAR

    Science.gov (United States)

    Heather Kramer; Brandon Collins; Maggi Kelly; Scott Stephens

    2014-01-01

    We investigated the relationship between LiDAR and ladder fuels in the northern Sierra Nevada, California USA. Ladder fuels are often targeted in hazardous fuel reduction treatments due to their role in propagating fire from the forest floor to tree crowns. Despite their importance, ladder fuels are difficult to quantify. One common approach is to calculate canopy base...

  10. Selectivity of fish ladders: a bottleneck in Neotropical fish movement

    Directory of Open Access Journals (Sweden)

    Carlos Sérgio Agostinho

    Full Text Available Although dozens of fish ladders have been constructed at dams of Brazilian reservoirs, there are few studies evaluating their efficiency as a tool for the conservation of Neotropical ichthyofauna, especially for migratory species. Therefore, the present study evaluated the selectivity of the species that entered and ascended the fish ladder located next to Lajeado Dam (Luis Eduardo Magalhães Hydroelectric Power Plant on the Tocantins River. Samples were taken monthly from November, 2002 through October, 2003, in the resting pools of the ladder, using cast nets, and in the downstream stretch, using gillnets. The selectivity of the ladder in attracting fish was evaluated by comparing the occurrence, relative abundance, dominance and the congruence of abundance ranks of migratory and non-migratory species in the ladder and in the stretch of river immediately downstream. Species richness and fish abundance in the resting pools were used to evaluate selectivity along the ladder. The effects on selectivity by temporal variations in water level downriver and maximum flow velocity in the fish ladder were also analyzed. Out of the 130 species recorded downriver, 62.3% were caught in the ladder, and migratory species were clearly favored. However, more than 2/3 of the catch belonged to only three species (Rhaphiodon vulpinus, Psectrogaster amazonica and Oxydoras niger. Although the majority of the species that entered the ladder were able to reach its top, there was a sharp reduction in abundance of individuals towards the top. Temporal variations in the water level below the dam influenced richness and abundance of fish concentrated downstream and in the ladder, with lower values during periods of low water. In the ladder, a maximum flow velocity of 2.3 m/s, although also selective, proved to be more appropriate for fish ascension than a velocity of 2.8 m/s. It was concluded that the entry and ascension of the fish in the ladder were not congruent with

  11. Evaluation of the ZIG-ZAIDS game: an entertaining educational tool for HIV/Aids prevention

    Directory of Open Access Journals (Sweden)

    Virgínia T. Schall

    Full Text Available This article presents the evaluation process for the ZIG-ZAIDS game, investigating the material's applicability in formal and informal educational contexts, i.e., how the game has been used by health professionals, parents, and the target population (pre-adolescents, or children over 9 years old. The study involved evaluation questionnaires sent to a list of schools and institutions using the game, plus interviews and visits to places where the game was used as well as tested with groups of students. It also includes an analysis of evaluation previously sent by the authors to people who had requested the game. The results showed that the population's level of information is more relevant than age in relation to the game's impact. Another important aspect relates to ZIG-ZAIDS' applicability to different situations: training of health and teaching professionals; activities with street children; municipal institutions and events, schools, companies, communities, and health care centers. In summary, ZIG-ZAIDS was found to be an entertaining, creative, and innovative alternative for providing information on AIDS and sexuality.

  12. Evaluation of the ZIG-ZAIDS game: an entertaining educational tool for HIV/Aids prevention

    Directory of Open Access Journals (Sweden)

    Schall Virgínia T.

    1999-01-01

    Full Text Available This article presents the evaluation process for the ZIG-ZAIDS game, investigating the material's applicability in formal and informal educational contexts, i.e., how the game has been used by health professionals, parents, and the target population (pre-adolescents, or children over 9 years old. The study involved evaluation questionnaires sent to a list of schools and institutions using the game, plus interviews and visits to places where the game was used as well as tested with groups of students. It also includes an analysis of evaluation previously sent by the authors to people who had requested the game. The results showed that the population's level of information is more relevant than age in relation to the game's impact. Another important aspect relates to ZIG-ZAIDS' applicability to different situations: training of health and teaching professionals; activities with street children; municipal institutions and events, schools, companies, communities, and health care centers. In summary, ZIG-ZAIDS was found to be an entertaining, creative, and innovative alternative for providing information on AIDS and sexuality.

  13. The snakes and ladders of FM service excellence

    OpenAIRE

    Price, Ilfryn; Mccarroll, Patricia

    2015-01-01

    A report to accompany a workshop and gamification event at EFMC 2015 in Glasgow.\\ud \\ud Snakes and Ladders is an ancient Indian board game regarded today as a worldwide classic. The historic version had its root in morality lessons, where a player's progression up the board represented a life journey complicated by virtues (ladders) and vices (snakes). Our version brings back the morality element by associating each ladder and snake with enablers or barriers to service excellence in FM all id...

  14. Pamięć przyswojona. Koncepcja polskiego doświadczenia zagłady Żydów jako traumy zbiorowej w świetle rewizji kategorii świadka

    Directory of Open Access Journals (Sweden)

    Elżbieta Janicka

    2016-01-01

    kwestia to, czy większość dominującą można ukazać jako nieformalną instancję sprawującą rodzaj kontroli społecznej nad kompletnością Zagłady jako niemieckiej zbrodni państwowej. W centrum namysłu znajdują się także dotychczasowe funkcje kategorii świadka (bystander/onlooker, kategorii obojętności oraz koncepcji Zagłady jako traumy nieżydowskiego świadka. Funkcje te niejednokrotnie bowiem polegały na eliminacji z pola widzenia historycznego konkretu i jego społeczno-kulturowych uwarunkowań. W tym sensie można mówić o koncepcji pamięci nieprzyswojonej (polskiej traumy Zagłady jako strategii przyswojenia pamięci Zagłady w sposób niezagrażający dominującej opowieści o przeszłości i tożsamości grupy większościowej. Tekst proponuje ponadto dekonstrukcję kategorii dialogu polsko-żydowskiego ze wskazaniem na zjawiska fałszywej symetrii i fałszywej uniwersalizacji, których częstą konsekwencją jest definiowanie antysemityzmu i Zagłady w kategoriach konfliktu międzygrupowego. Inspiracją do podjęcia namysłu była paradygmatyczna praca Michaela C. Steinlaufa Bondage to the Dead: Poland and the Memory of the Holocaust z 1997 roku, której polskie wydanie – zatytułowane Pamięć nieprzyswojona. Polska pamięć Zagłady – ukazało się w roku 2001 w tłumaczeniu Agaty Tomaszewskiej.

  15. Vehicles In Highway Communication System Using ZigBee And Bluetooth Network

    Directory of Open Access Journals (Sweden)

    EiThuzarKhin

    2015-06-01

    Full Text Available Abstract Globally many vehicle types operate on the highway system. And highway infrastructure stakeholders have developed a number of products intended to facilitate the identification of critical assets and provide guidance for conductiong security planning. Many of these productsare conducted as joint efforts between the state highway agencies.The main aim of the system is to have a network between Roadside Unit RSU and On-Board Unit OBU and between On-Board Unit OBU and another On-Board Unit OBU . ZigBee is a consortium of software hardware and services companies having improved a common standard for wireless networking of sensors and microcontrollers.Bluetooth is a technology of wireless standard for exchanging data for short distances. In this article we point out sending data to the drivers via not only ZigBee module but also Bluetooth module.

  16. Baryons and ladders

    International Nuclear Information System (INIS)

    Ball, R.D.

    1990-01-01

    By formal manipulation of the QCD functional integral we arrive at a relativistic low energy effective theory of non-local color singlet mesons and baryons, which at tree level sums up ladders of effective glue exchange between constituent quarks. (orig.)

  17. 29 CFR 1910.25 - Portable wood ladders.

    Science.gov (United States)

    2010-07-01

    ... for the construction, care, and use of the common types of portable wood ladders, in order to insure... density wood shall not be used. (ii) [Reserved] (2) [Reserved] (c) Construction requirements. (1... 29 Labor 5 2010-07-01 2010-07-01 false Portable wood ladders. 1910.25 Section 1910.25 Labor...

  18. Understanding the Behaviour of Infinite Ladder Circuits

    Science.gov (United States)

    Ucak, C.; Yegin, K.

    2008-01-01

    Infinite ladder circuits are often encountered in undergraduate electrical engineering and physics curricula when dealing with series and parallel combination of impedances, as a part of filter design or wave propagation on transmission lines. The input impedance of such infinite ladder circuits is derived by assuming that the input impedance does…

  19. Gluing Ladder Feynman Diagrams into Fishnets

    International Nuclear Information System (INIS)

    Basso, Benjamin; Dixon, Lance J.; Stanford University, CA; University of California, Santa Barbara, CA

    2017-01-01

    We use integrability at weak coupling to compute fishnet diagrams for four-point correlation functions in planar Φ "4 theory. Our results are always multilinear combinations of ladder integrals, which are in turn built out of classical polylogarithms. The Steinmann relations provide a powerful constraint on such linear combinations, which leads to a natural conjecture for any fishnet diagram as the determinant of a matrix of ladder integrals.

  20. Research of home energy management system based on technology of PLC and ZigBee

    Science.gov (United States)

    Wei, Qi; Shen, Jiaojiao

    2015-12-01

    In view of the problem of saving effectively energy and energy management in home, this paper designs a home energy intelligent control system based on power line carrier communication and wireless ZigBee sensor networks. The system is based on ARM controller, power line carrier communication and wireless ZigBee sensor network as the terminal communication mode, and realizes the centralized and intelligent control of home appliances. Through the combination of these two technologies, the advantages of the two technologies complement each other, and provide a feasible plan for the construction of energy-efficient, intelligent home energy management system.

  1. Fish ladders: safe fish passage or hotspot for predation?

    Directory of Open Access Journals (Sweden)

    Angelo Antonio Agostinho

    Full Text Available Fish ladders are a strategy for conserving biodiversity, as they can provide connectivity between fragmented habitats and reduce predation on shoals that accumulate immediately below dams. Although the impact of predation downstream of reservoirs has been investigated, especially in juvenile salmonids during their downstream movements, nothing is known about predation on Neotropical fish in the attraction and containment areas commonly found in translocation facilities. This study analysed predation in a fish passage system at the Lajeado Dam on the Tocantins River in Brazil. The abundance, distribution, and the permanence (time spent of large predatory fish along the ladder, the injuries imposed by piranhas during passage and the presence of other vertebrate predators were investigated. From December 2002 to October 2003, sampling was conducted in four regions (downstream, along the ladder, in the forebay, and upstream of the reservoir using gillnets, cast nets and counts or visual observations. The captured fish were tagged with thread and beads, and any mutilations were registered. Fish, birds and dolphins were the main predator groups observed, with a predominance of the first two groups. The entrance to the ladder, in the downstream region, was the area with the highest number of large predators and was the only region with relevant non-fish vertebrates. The main predatory fish species were Rhaphiodon vulpinus, Hydrolycus armatus, and Serrasalmus rhombeus. Tagged individuals were detected predating along the ladder for up to 90 days. Mutilations caused by Serrasalmus attacks were noted in 36% of species and 4% of individuals at the top of the ladder. Our results suggested that the high density of fish in the restricted ladder environment, which is associated with injuries suffered along the ladder course and the presence of multiple predator groups with different predation strategies, transformed the fish corridor into a hotspot for

  2. The Design and Implementation of Smart Monitoring System for Large-Scale Railway Maintenance Equipment Cab Based on ZigBee Wireless Sensor Network

    OpenAIRE

    Hairui Wang; Junfu Yu

    2014-01-01

    In recent years, organizations use IEEE 802.15.4 and ZigBee technology to deliver solution in variety areas including home environment monitoring. ZigBee technology has advantages on low-cost, low power consumption and self-forming. With the rapid expansion of the Internet, there is the requirement for remote monitoring large-scale railway maintenance equipment cab. This paper discusses the disadvantages of the existing smart monitoring system, and proposes a solution. A ZigBee wireless senso...

  3. Heat Transport in Gapped Spin-Chain Systems

    International Nuclear Information System (INIS)

    Shimshoni, E.

    2006-01-01

    Full Text: We study the contribution of magnetic excitations to the heat transport in gapped spin-chain systems. These systems are characterized by a substantially enhanced heat conductivity, which can be traced back to the existence of weakly violated conservation laws. We focus particularly on the behavior of clean two-leg spin ladder compounds, where one-dimensional exotic spin excitations are coupled to three-dimensional phonons. We show that the contributions of the two types of heat carriers can not be easily disentangled. Depending on the ratios of spin gaps and the Debye energy, the heat conductivity can be either exponentially increasing or exponentially decreasing as a function of temperature (T). In addition, the magnetic contribution to the total heat conductivity may be either positive or negative. We discuss its T-dependence in various possible regimes, and note that in most regimes it is dominated by spin-phonon drag: the two types of heat carriers have almost the

  4. Research and design of photovoltaic power monitoring system based on Zig Bee

    Science.gov (United States)

    Zhu, Lijuan; Yun, Zhonghua; Bianbawangdui; Bianbaciren

    2018-01-01

    In order to monitor and study the impact of environmental parameters on photovoltaic cells, a photovoltaic cell monitoring system based on ZigBee is designed. The system uses ZigBee wireless communication technology to achieve real-time acquisition of P-I-V curves and environmental parameters of terminal nodes, and transfer the data to the coordinator, the coordinator communicates with the STM32 through the serial port. In addition, STM32 uses the serial port to transfer data to the host computer written by LabVIEW, and the collected data is displayed in real time, as well as stored in the background database. The experimental results show that the system has a stable performance, accurate measurement, high sensitivity, high reliability, can better realize real-time collection of photovoltaic cell characteristics and environmental parameters.

  5. A balanced intervention ladder: promoting autonomy through public health action.

    Science.gov (United States)

    Griffiths, P E; West, C

    2015-08-01

    The widely cited Nuffield Council on Bioethics 'Intervention Ladder' structurally embodies the assumption that personal autonomy is maximized by non-intervention. Consequently, the Intervention Ladder encourages an extreme 'negative liberty' view of autonomy. Yet there are several alternative accounts of autonomy that are both arguably superior as accounts of autonomy and better suited to the issues facing public health ethics. We propose to replace the one-sided ladder, which has any intervention coming at a cost to autonomy, with a two-sided 'Balanced Intervention Ladder,' where intervention can either enhance or diminish autonomy. We show that not only the alternative, richer accounts of autonomy but even Mill's classic version of negative liberty puts some interventions on the positive side of the ladder. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  6. Recovery Act: Water Heater ZigBee Open Standard Wireless Controller

    Energy Technology Data Exchange (ETDEWEB)

    Butler, William P. [Emerson Electric Co., St. Louis, MO (United States); Buescher, Tom [Emerson Electric Co., St. Louis, MO (United States)

    2014-04-30

    The objective of Emerson's Water Heater ZigBee Open Standard Wireless Controller is to support the DOE's AARA priority for Clean, Secure Energy by designing a water heater control that levels out residential and small business peak electricity demand through thermal energy storage in the water heater tank.

  7. A reliable transmission protocol for ZigBee-based wireless patient monitoring.

    Science.gov (United States)

    Chen, Shyr-Kuen; Kao, Tsair; Chan, Chia-Tai; Huang, Chih-Ning; Chiang, Chih-Yen; Lai, Chin-Yu; Tung, Tse-Hua; Wang, Pi-Chung

    2012-01-01

    Patient monitoring systems are gaining their importance as the fast-growing global elderly population increases demands for caretaking. These systems use wireless technologies to transmit vital signs for medical evaluation. In a multihop ZigBee network, the existing systems usually use broadcast or multicast schemes to increase the reliability of signals transmission; however, both the schemes lead to significantly higher network traffic and end-to-end transmission delay. In this paper, we present a reliable transmission protocol based on anycast routing for wireless patient monitoring. Our scheme automatically selects the closest data receiver in an anycast group as a destination to reduce the transmission latency as well as the control overhead. The new protocol also shortens the latency of path recovery by initiating route recovery from the intermediate routers of the original path. On the basis of a reliable transmission scheme, we implement a ZigBee device for fall monitoring, which integrates fall detection, indoor positioning, and ECG monitoring. When the triaxial accelerometer of the device detects a fall, the current position of the patient is transmitted to an emergency center through a ZigBee network. In order to clarify the situation of the fallen patient, 4-s ECG signals are also transmitted. Our transmission scheme ensures the successful transmission of these critical messages. The experimental results show that our scheme is fast and reliable. We also demonstrate that our devices can seamlessly integrate with the next generation technology of wireless wide area network, worldwide interoperability for microwave access, to achieve real-time patient monitoring.

  8. Boat boarding ladder placement

    Science.gov (United States)

    1998-04-01

    Presented in three volumes; 'Boat Boarding Ladder Placement,' which explores safety considerations including potential for human contact with a rotating propeller; 'Boat Handhold Placement,' which explores essential principles and methods of fall con...

  9. Designing and Implementing Performance-Based Career Ladder Plans.

    Science.gov (United States)

    Hawley, Willis D.

    1985-01-01

    Reviews the factors that any teacher motivation plan must incorporate to be effective and outlines 11 principles that should be followed in designing career ladder plans to meet teacher needs, increase teacher competence, and facilitate effective instruction. Warns against potential pitfalls in career ladder plans. (PGD)

  10. Measuring a Country's Product Ladder and Technology Level based on Trade Flow

    Directory of Open Access Journals (Sweden)

    Jong-il Kim

    2006-06-01

    Full Text Available This study tries to quantify the technology level of products based on the concept of product ladder. While many studies on country technology competitiveness use the aggregate indices such as total factor productivity and revealed comparative advantage, this study estimates the ranking of about 2000 products in product ladder by using SITC 5 digit level export data. Based on the product ladder, this study measures the country and industry ranking and explores the characteristics of the ranking. It provides the international comparison of inter-industry and intra-industry ranking differences in product ladder. The statistical relationships between the ranking in product ladder and the determinants of technology level such as R&D and physical capital investment and wage, confirms that the measured ranking in product ladder could be regarded as an indirect indicator of technology level. The product ladder is applied to the estimation of production function to see the effect of the product differentiation on labor productivity.

  11. Dipoles on a Two-leg Ladder

    DEFF Research Database (Denmark)

    Gammelmark, Søren; Zinner, Nikolaj Thomas

    2013-01-01

    We study polar molecules with long-range dipole-dipole interactions confined to move on a two-leg ladder for different orientations of the molecular dipole moments with respect to the ladder. Matrix product states are employed to calculate the many-body ground state of the system as function...... that there is a critical angle at which ordering disappears. This angle is slightly larger than the angle at which the dipoles are non-interacting along a single leg. This behavior should be observable using current experimental techniques....

  12. PT-symmetric ladders with a scattering core

    Energy Technology Data Exchange (ETDEWEB)

    D' Ambroise, J. [Department of Mathematics, Amherst College, Amherst, MA 01002-5000 (United States); Lepri, S. [CNR – Consiglio Nazionale delle Ricerche, Istituto dei Sistemi Complessi, via Madonna del piano 10, I-50019 Sesto Fiorentino (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Firenze, via G. Sansone 1, I-50019 Sesto Fiorentino (Italy); Malomed, B.A. [Department of Physical Electronics, School of Electrical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978 (Israel); Kevrekidis, P.G. [Department of Mathematics and Statistics, University of Massachusetts, Amherst, MA 01003-9305 (United States)

    2014-08-01

    We consider a PT-symmetric chain (ladder-shaped) system governed by the discrete nonlinear Schrödinger equation where the cubic nonlinearity is carried solely by two central “rungs” of the ladder. Two branches of scattering solutions for incident plane waves are found. We systematically construct these solutions, analyze their stability, and discuss non-reciprocity of the transmission associated with them. To relate the results to finite-size wavepacket dynamics, we also perform direct simulations of the evolution of the wavepackets, which confirm that the transmission is indeed asymmetric in this nonlinear system with the mutually balanced gain and loss. - Highlights: • We model a PT-symmetric ladder system with cubic nonlinearity on two central rungs. • We examine non-reciprocity and stability of incident plane waves. • Simulations of wavepackets confirm our results.

  13. Low Cost ZigBee Protocol Based Laboratory Platforms

    Directory of Open Access Journals (Sweden)

    Alvaro Romero-Acero

    2013-11-01

    Full Text Available This paper presents a low cost wireless communication platform, based on the ZigBee protocol. It is designed with the purpose to strengthen the use of information technology in the classroom. Guides laboratory practices are focused on developing undergraduate engineering students to the area of telecommunications. The platform structure is composed of: Labs custom designed, web tools embedded wireless communication system for data acquisition in real time, and the Human Machine Interface (HMI, which records analog data and digital. 

  14. Development of ultra-light pixelated ladders for an ILC vertex detector

    CERN Document Server

    Chon-Sen, N.; Claus, G.; De Masi, R.; Deveaux, M.; Dulinski, W.; Goffe, M.; Goldstein, J.; Gregor, I.-M.; Hu-Guo, Ch.; Imhoff, M.; Muntz, C.; Nomerotski, A.; Santos, C.; Schrader, C.; Specht, M.; Stroth, J.; Winter, M.

    2010-01-01

    The development of ultra-light pixelated ladders is motivated by the requirements of the ILD vertex detector at ILC. This paper summarizes three projects related to system integration. The PLUME project tackles the issue of assembling double-sided ladders. The SERWIETE project deals with a more innovative concept and consists in making single-sided unsupported ladders embedded in an extra thin plastic enveloppe. AIDA, the last project, aims at building a framework reproducing the experimental running conditions where sets of ladders could be tested.

  15. Review of the Current Body Fat Taping Method and Its Importance in Ascertaining Fitness Levels in the United States Marine Corps

    Science.gov (United States)

    2015-06-01

    exercises include isometric movements such as the “tummy tightner” and the back flexor (Figure 2). 12 Figure 1. A Female Marine...a 20-foot rope climb, was to test an individual’s strength . The third event required a Marine to run 50 yards in a zig-zag pattern followed by a...assumption that such women would have greater strength and stamina with regard to physical fitness (Institute of Medicine 1998, 34). In 1987, DODI

  16. A highly conspicuous mineralized composite photonic architecture in the translucent shell of the blue-rayed limpet

    OpenAIRE

    Li, Ling; Kolle, Stefan; Weaver, James C.; Ortiz, Christine; Aizenberg, Joanna; Kolle, Mathias

    2015-01-01

    Many species rely on diverse selections of entirely organic photonic structures for the manipulation of light and the display of striking colours. Here we report the discovery of a mineralized hierarchical photonic architecture embedded within the translucent shell of the blue-rayed limpet Patella pellucida. The bright colour of the limpet’s stripes originates from light interference in a periodically layered zig-zag architecture of crystallographically co-oriented calcite lamellae. Beneath t...

  17. An Analysis of QoS in ZigBee Network Based on Deviated Node Priority

    Directory of Open Access Journals (Sweden)

    Md. Jaminul Haque Biddut

    2016-01-01

    Full Text Available ZigBee is an IEEE 802.15.4 standardized communication protocol. It forms a flawless Wireless Sensor Network (WSN standard for interoperability at all levels of the network, particularly the application level which most closely touches the user. A large number of devices from different vendors can work seamlessly. These devices act as a network and send huge data traffic to the Coordinator. End devices at different zones have different roles in communication with each other. There has been a lack in executing their requests in a synchronized way based on task priority. This lack leads to massive data traffic loss and degrades the Quality of Service (QoS. One of the challenges is to analyze the QoS parameters in ZigBee network that help to detect the overall network performance. The contribution of this paper is twofold; first, a ZigBee Network is implemented based on node priority. It demonstrates a method to generate a new priority of devices with respect to their existing priority and zones’ priority as well. Second, the QoS is analyzed based on the new priority status for tasks preference purposes. The outcome of this paper shows that the QoS of the network is more conspicuous than non-priority based network.

  18. The latrine ownership ladder

    DEFF Research Database (Denmark)

    Obeng, Peter Appiah; Keraita, Bernard; Oduro-Kwarteng, Sampson

    2015-01-01

    the challenges that undermine sanitation uptake in low-income peri-urban areas and the prospects of various levels of facility sharing as conceived in the latrine ownership ladder approach. Findings – The authors argue that the infrastructural and other socio-economic challenges of low-income peri-urban areas...... to the promotion of household latrines. The paper identifies provision of special concessions for peri-urban areas in policy formulation, education and technical support to households, regulation and enforcement of sanitation by-laws among complimentary policy interventions to make the latrine ownership ladder...... approach more effective. Originality/value – The paper provides an insight into the debate on redefining improved sanitation in the post-2015 era of the Millennium Development Goals and offers policy alternatives to policy makers in low-income countries seeking to accelerate the uptake of improved latrines...

  19. Role of Structural Asymmetry in Controlling Drop Spacing in Microfluidic Ladder Networks

    Science.gov (United States)

    Wang, William; Maddala, Jeevan; Vanapalli, Siva; Rengasamy, Raghunathan

    2012-02-01

    Manipulation of drop spacing is crucial to many processes in microfluidic devices including drop coalescence, detection and storage. Microfluidic ladder networks ---where two droplet-carrying parallel channels are connected by narrow bypass channels through which the motion of drops is forbidden---have been proposed as a means to control relative separation between pairs of drops. Prior studies in microfluidic ladder networks with vertical bypasses, which possess fore-aft structural symmetry, have revealed that pairs of drops can only undergo reduction in drop spacing at the ladder exit. We investigate the dynamics of drops in microfluidic ladder networks with both vertical and slanted bypasses. Our analytical results indicate that unlike symmetric ladder networks, structural asymmetry introduced by a single slanted bypass can be used to modulate the relative spacing between drops, enabling them to contract, synchronize, expand or even flip at the ladder exit. Our experiments confirm all the behaviors predicted by theory. Numerical analysis further shows that ladders containing several identical bypasses can only linearly transform the input drop spacing. Finally, we find that ladders with specific combinations of vertical and slanted bypasses can generate non-linear transformation of input drop spacing, despite the absence of drop decision-making events at the bypass junctions.

  20. Towards automatic verification of ladder logic programs

    OpenAIRE

    Zoubek , Bohumir; Roussel , Jean-Marc; Kwiatkowska , Martha

    2003-01-01

    International audience; Control system programs are usually validated by testing prior to their deployment. Unfortunately, testing is not exhaustive and therefore it is possible that a program which passed all the required tests still contains errors. In this paper we apply techniques of automatic verification to a control program written in ladder logic. A model is constructed mechanically from the ladder logic program and subjected to automatic verification against requirements that include...

  1. The massless supersymmetric ladder with L rungs

    International Nuclear Information System (INIS)

    Rossi, G.C.; Stanev, Ya.S.

    2009-01-01

    We show that in the massless N=1 supersymmetric Wess-Zumino theory it is possible to devise a computational strategy by which the x-space calculation of the ladder 4-point correlators can be carried out without introducing any regularization. As an application we derive a representation valid at all loop orders in terms of conformal invariant integrals. We obtain an explicit expression of the 3-loop ladder diagram for collinear external points

  2. Performance of wave function and density functional methods for water hydrogen bond spin-spin coupling constants.

    Science.gov (United States)

    García de la Vega, J M; Omar, S; San Fabián, J

    2017-04-01

    Spin-spin coupling constants in water monomer and dimer have been calculated using several wave function and density functional-based methods. CCSD, MCSCF, and SOPPA wave functions methods yield similar results, specially when an additive approach is used with the MCSCF. Several functionals have been used to analyze their performance with the Jacob's ladder and a set of functionals with different HF exchange were tested. Functionals with large HF exchange appropriately predict 1 J O H , 2 J H H and 2h J O O couplings, while 1h J O H is better calculated with functionals that include a reduced fraction of HF exchange. Accurate functionals for 1 J O H and 2 J H H have been tested in a tetramer water model. The hydrogen bond effects on these intramolecular couplings are additive when they are calculated by SOPPA(CCSD) wave function and DFT methods. Graphical Abstract Evaluation of the additive effect of the hydrogen bond on spin-spin coupling constants of water using WF and DFT methods.

  3. Discussing Laddering Application by the Means-End Chain Theory

    Science.gov (United States)

    Veludo-de-Oliveira, Tania Modesto; Ikeda, Ana Akemi; Campomar, Marcos Cortez

    2006-01-01

    This article aims at analyzing laddering as a technique of qualitative research, emphasizing the procedures for data collection, analysis and interpretation, and its main limitations as well. "Laddering refers to an in-depth, one-on-one interviewing technique used to develop an understanding of how consumers translate the attributes of products…

  4. Design of Remote Monitoring System of Irrigation based on GSM and ZigBee Technology

    Science.gov (United States)

    Xiao xi, Zheng; Fang, Zhao; Shuaifei, Shao

    2018-03-01

    To solve the problems of low level of irrigation and waste of water resources, a remote monitoring system for farmland irrigation based on GSM communication technology and ZigBee technology was designed. The system is composed of sensors, GSM communication module, ZigBee module, host computer, valve and so on. The system detects and closes the pump and the electromagnetic valve according to the need of the system, and transmits the monitoring information to the host computer or the user’s Mobile phone through the GSM communication network. Experiments show that the system has low power consumption, friendly man-machine interface, convenient and simple. It can monitor agricultural environment remotely and control related irrigation equipment at any time and place, and can better meet the needs of remote monitoring of farmland irrigation.

  5. Biomechanical analysis of loading/unloading a ladder on a truck.

    Science.gov (United States)

    Moriguchi, Cristiane Shinohara; Carnaz, Leticia; de Miranda, Luiz Carlos; Marklin, Richard William; Coury, Helenice Jane Cote Gil

    2012-01-01

    Loading/unloading a ladder on vehicles are frequent tasks and involve overhead handling that may expose workers to risk factors of shoulder musculoskeletal disorders. The objective of the present study was to evaluate posture, forces required and perceived exertion when loading and unloading the ladder on a utility truck. Thirteen male overhead line workers from an electric utility in Brazil participated in this study. Shoulder elevation angle was measured using inclinometers. The required force to load/unload the ladder was measured by dynamometer. Subjective assessment of the perceived exertion was recorded to compare the exertion reported during the test conditions to the field conditions. The task of loading/unloading the ladder presented risks of shoulder musculoskeletal disorders (MSDs) to workers because it requires high levels of force (approximately 60% of the maximal force) combined with overhead posture of the shoulders (more than 100° from the neutral posture). Age and height presented to interfere in biomechanical risks presented in load/unload task. There was no significant difference between the subjective exertion during the test conditions and handling the ladder in the field. Ergonomic intervention is recommended to reduce these risks for shoulder MSDs.

  6. 46 CFR 72.05-20 - Stairways, ladders, and elevators.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Stairways, ladders, and elevators. 72.05-20 Section 72.05-20 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PASSENGER VESSELS CONSTRUCTION AND ARRANGEMENT Structural Fire Protection § 72.05-20 Stairways, ladders, and elevators. (a)(1) Except as further noted the provisions of this...

  7. Compressive strain induced enhancement in thermoelectric-power-factor in monolayer MoS2 nanosheet

    International Nuclear Information System (INIS)

    Dimple; Jena, Nityasagar; De Sarkar, Abir

    2017-01-01

    Strain and temperature induced tunability in the thermoelectric properties in monolayer MoS 2 (ML-MoS 2 ) has been demonstrated using density functional theory coupled to semi-classical Boltzmann transport theory. Compressive strain, in general and uniaxial compressive strain (along the zig-zag direction), in particular, is found to be most effective in enhancing the thermoelectric power factor, owing to the higher electronic mobility and its sensitivity to lattice compression along this direction. Variation in the Seebeck coefficient and electronic band gap with strain is found to follow the Goldsmid–Sharp relation. n-type doping is found to raise the relaxation time-scaled thermoelectric power factor higher than p-type doping and this divide widens with increasing temperature. The relaxation time-scaled thermoelectric power factor in optimally n-doped ML-MoS 2 is found to undergo maximal enhancement under the application of 3% uniaxial compressive strain along the zig-zag direction, when both the ( direct ) electronic band gap and the Seebeck coefficient reach their maximum, while the electron mobility drops down drastically from 73.08 to 44.15 cm 2 V −1 s −1 . Such strain sensitive thermoelectric responses in ML-MoS 2 could open doorways for a variety of applications in emerging areas in 2D-thermoelectrics, such as on-chip thermoelectric power generation and waste thermal energy harvesting. (paper)

  8. Development of laser diode pumped Nd:glass slab laser driver for the inertial fusion energy

    International Nuclear Information System (INIS)

    Yamanaka, Masanobu; Kanabe, Tadashi; Yasuhara, Ryo

    2002-01-01

    A diode-pumped solid state laser (DPSSL) is promising candidate of reactor driver for Inertial Fusion Energy (IFE). As a first step of a driver development for the IFE, we are developing a laser diode pumped zig-zag Nd:glass slab laser amplifier system HALNA 10 (High Average-power Laser for Nuclear-fusion Application) which can generated an output of 10 J per pulse at 1053 nm in 10 Hz operation. The water-cooled zig zag Nd:glass slab is pumped from both sides by 803 nm AIGaAs laser diode (LD) module, each LD module has an emitting area of 420 mm x 10 mm and two LD modules generate in total 218 (max.) kW peak power with 2.6 kW/cm 2 peak intensity at 10 Hz repetition rate. We have obtained in first-stage experiment 8.5 J output energy at 0.5 Hz with a beam quality of 2 times diffraction limited far-field pattern, which nearly confirmed our conceptual design. Since the key issue for the IFE DPSSL drive module were almost satisfactory, we have a confidence that a next 100 J x 10 Hz DPSSL module (HALNA 100) can be constructed. Thermal effects in laser slab, Faraday rotator, Faraday isolator and Pockets cell and their managements are discussed.

  9. ZigBee-Based Telemetry System

    Directory of Open Access Journals (Sweden)

    L. Khriji

    2010-12-01

    Full Text Available Nowadays, there is a significant improvement in technology regarding healthcare. Real-time monitoring systems improve the quality of life of patients as well as the performance of hospitals and healthcare centers. In this paper, we present an implementation of a designed framework of a telemetry system using ZigBee technology for automatic and real-time monitoring of Biomedical signals. These signals are collected and processed using 2-tiered subsystems. The first subsystem is the mobile device which is carried on the body and runs a number of biosensors. The second subsystem performs further processing by a local base station using the raw data which is transmitted on-request by the mobile device. The processed data as well as its analysis are then continuously monitored and diagnosed through a human-machine interface. The system should possess low power consumption, low cost and advanced configuration possibilities. This paper accelerates the digital convergence age through continual research and development of technologies related to healthcare.

  10. Topological phases in frustrated synthetic ladders with an odd number of legs

    Science.gov (United States)

    Barbarino, Simone; Dalmonte, Marcello; Fazio, Rosario; Santoro, Giuseppe E.

    2018-01-01

    The realization of the Hofstadter model in a strongly anisotropic ladder geometry has now become possible in one-dimensional optical lattices with a synthetic dimension. In this work, we show how the Hofstadter Hamiltonian in such ladder configurations hosts a topological phase of matter which is radically different from its two-dimensional counterpart. This topological phase stems directly from the hybrid nature of the ladder geometry and is protected by a properly defined inversion symmetry. We start our analysis by considering the paradigmatic case of a three-leg ladder which supports a topological phase exhibiting the typical features of topological states in one dimension: robust fermionic edge modes, a degenerate entanglement spectrum, and a nonzero Zak phase; then, we generalize our findings—addressable in the state-of-the-art cold-atom experiments—to ladders with a higher number of legs.

  11. Triptycene-based ladder monomers and polymers, methods of making each, and methods of use

    KAUST Repository

    Pinnau, Ingo

    2015-02-05

    Embodiments of the present disclosure provide for a triptycene-based A-B monomer, a method of making a triptycene-based A-B monomer, a triptycene-based ladder polymer, a method of making a triptycene-based ladder polymers, a method of using triptycene-based ladder polymers, a structure incorporating triptycene-based ladder polymers, a method of gas separation, and the like.

  12. UAV telemetry communications using ZigBee protocol

    Science.gov (United States)

    Nasution, T. H.; Siregar, I.; Yasir, M.

    2017-10-01

    Wireless communication has been widely used in various fields or disciplines such as agriculture, health, engineering, military, and aerospace so as to support the work in that field. The communication technology is typically used for controlling devices and data monitoring. One development of wireless communication is the widely used telemetry system used to reach areas that cannot be reached by humans using UAV (Unmanned Aerial Vehicle) or unmanned aircraft. In this paper we discuss the design of telemetry system in UAV using ZigBee protocol. From the test obtained the system can work well with visualization displays without pause is 20 data per second with a maximum data length of 120 characters.

  13. Progress in the Supramolecular Architecture-directed Synthesis of Perfect Ladder Polysiloxanes

    Institute of Scientific and Technical Information of China (English)

    C; C; Han

    2007-01-01

    1 Introduction Ladder polysiloxanes (LPSs) including organo-bridged ladder polyorganosiloxanes (R-OLPSs, R is side group) and ladder polyorganosilsesquioxanes (R-LPSQs) have intrigued polymer chemists for about 50 years due to their excellent resistance to all kinds of degradations. However, their synthesis has been a great challenge to polymer chemists. Here, we describe a new approach based on supramolecular concerted interactions as follows.2 Results2.1 Synthesis of Perfect R-OLPSsA series of real ...

  14. Self-organised fractional quantisation in a hole quantum wire

    Science.gov (United States)

    Gul, Y.; Holmes, S. N.; Myronov, M.; Kumar, S.; Pepper, M.

    2018-03-01

    We have investigated hole transport in quantum wires formed by electrostatic confinement in strained germanium two-dimensional layers. The ballistic conductance characteristics show the regular staircase of quantum levels with plateaux at n2e 2/h, where n is an integer, e is the fundamental unit of charge and h is Planck’s constant. However as the carrier concentration is reduced, the quantised levels show a behaviour that is indicative of the formation of a zig-zag structure and new quantised plateaux appear at low temperatures. In units of 2e 2/h the new quantised levels correspond to values of n  =  1/4 reducing to 1/8 in the presence of a strong parallel magnetic field which lifts the spin degeneracy but does not quantise the wavefunction. A further plateau is observed corresponding to n  =  1/32 which does not change in the presence of a parallel magnetic field. These values indicate that the system is behaving as if charge was fractionalised with values e/2 and e/4, possible mechanisms are discussed.

  15. ZigBee’s Received Signal Strength and Latency Evaluation under Varying Environments

    Directory of Open Access Journals (Sweden)

    H. H. R. Sherazi

    2016-01-01

    Full Text Available Being self-configured, self-organized, and self-healing low power technology, ZigBee has obtained significant attention in last few years for achieving ubiquitous communication among various devices within a Personal Area Network (PAN. Even after a decade of its emergence, it has been well serving the communication needs of numerous modern applications belonging to multiple industries and is still a spotlight for the researchers working on certain aspects to enhance productivity along with a major cost reduction. Despite its robust communication nature, it heavily depends upon the context and is prone to the external effects that may cause a serious threat to prospective applications. This paper presents the novel experimental analysis conducted on real test beds to evaluate the impact of continuously changing communication environment on various parameters, for example, RSSI (Received Signal Strength Indicator and latency in the presence of multiple obstacles that may lead to severe degradation in the overall performance. Eventually, we suggest a suitable frame size for ZigBee based on our results deduced from the experimental study.

  16. Testing ZigBee Motes for Monitoring Refrigerated Vegetable Transportation under Real Conditions

    Directory of Open Access Journals (Sweden)

    Luis Ruiz-Garcia

    2010-05-01

    Full Text Available Quality control and monitoring of perishable goods during transportation and delivery services is an increasing concern for producers, suppliers, transport decision makers and consumers. The major challenge is to ensure a continuous ‘cold chain’ from producer to consumer in order to guaranty prime condition of goods. In this framework, the suitability of ZigBee protocol for monitoring refrigerated transportation has been proposed by several authors. However, up to date there was not any experimental work performed under real conditions. Thus, the main objective of our experiment was to test wireless sensor motes based in the ZigBee/IEEE 802.15.4 protocol during a real shipment. The experiment was conducted in a refrigerated truck traveling through two countries (Spain and France which means a journey of 1,051 kilometers. The paper illustrates the great potential of this type of motes, providing information about several parameters such as temperature, relative humidity, door openings and truck stops. Psychrometric charts have also been developed for improving the knowledge about water loss and condensation on the product during shipments.

  17. Evidence of Hg-chain formation in HgxTiS2: a 199mHg-TDPAC study

    International Nuclear Information System (INIS)

    Troeger, W.; Butz, T.; Ouvrard, G.

    1993-01-01

    We determined the 199m Hg nuclear quadrupole interaction in the ''misfit'' or ''superstoichiometric'' compound Hg x TiS 2 by time differential perturbed angular correlation. A unique Hg-site with ν Q = 511(1) MHz and η = 0.410(4) was observed, irrespective of the Hg-uptake (2/3 ≤ x ≤ 4/3). We propose a model of Hg-Hg zig-zag chains which accounts for these observations as well as for the X-ray diffraction data. (orig.)

  18. Convection in a nematic liquid crystal with homeotropic alignment and heated from below

    Energy Technology Data Exchange (ETDEWEB)

    Ahlers, G. [Univ. of California, Santa Barbara, CA (United States)

    1995-12-31

    Experimental results for convection in a thin horizontal layer of a homeotropically aligned nematic liquid crystal heated from below and in a vertical magnetic field are presented. A subcritical Hopf bifurcation leads to the convecting state. There is quantitative agreement between the measured and the predicted bifurcation line as a function of magnetic field. The nonlinear state near the bifurcation is one of spatio-temporal chaos which seems to be the result of a zig-zag instability of the straight-roll state.

  19. Chiral phase from three-spin interactions in an optical lattice

    International Nuclear Information System (INIS)

    D'Cruz, Christian; Pachos, Jiannis K.

    2005-01-01

    A spin-1/2 chain model that includes three-spin interactions can effectively describe the dynamics of two species of bosons trapped in an optical lattice with a triangular-ladder configuration. A perturbative theoretical approach and numerical study of its ground state is performed that reveals a rich variety of phases and criticalities. We identify phases with periodicity one, two, or three, as well as critical points that belong in the same universality class as the Ising or the three-state Potts model. We establish a range of parameters, corresponding to a large degeneracy present between phases with period 2 and 3, that nests a gapless incommensurate chiral phase

  20. Assembly procedure for the silicon pixel ladder for PHENIX silicon vertex tracker

    International Nuclear Information System (INIS)

    Onuki, Y.; Akiba, Y.; En'yo, H.; Fujiwara, K.; Haki, Y.; Hashimoto, K.; Ichimiya, R.; Kasai, M.; Kawashima, M.; Kurita, K.; Kurosawa, M.; Mannel, E.J.; Nakano, K.; Pak, R.; Sekimoto, M.; Sondheim, W.E.; Taketani, A.; Togawa, M.; Yamamoto, Y.

    2009-01-01

    The silicon vertex tracker (VTX) will be installed in the summer of 2010 to enhance the physics capabilities of the Pioneering High Energy Nuclear Interaction eXperiment (PHENIX) experiment at Brookhaven National Laboratory. The VTX consists of two types of silicon detectors: a pixel detector and a strip detector. The pixel detector consists of 30 pixel ladders placed on the two inner cylindrical layers of the VTX. The ladders are required to be assembled with high precision, however, they should be assembled in both cost and time efficient manner. We have developed an assembly bench for the ladder with several assembly fixtures and a quality assurance (Q/A) system using a 3D measurement machine. We have also developed an assembly procedure for the ladder, including a method for dispensing adhesive uniformly and encapsulation of bonding wires. The developed procedures were adopted in the assembly of the first pixel ladder and satisfy the requirements.

  1. Movements of adult Atlantic salmon in relation to a hydroelectric dam and fish ladder

    International Nuclear Information System (INIS)

    Gowans, A.R.D.; Priede, I.G.

    1999-01-01

    The movements of adult Atlantic salmon were recorded as they approached, entered and ascended the pool-and-orifice fish ladder at Pitlochry Dam, Scotland. Thirty-nine returning salmon were captured in the River Tummel by rod-and-line angling, radio-tagged and released near where they were caught. The subsequent movements of each fish were then monitored. An electronic fish counter collected additional data on movements of untagged fish past a fixed point in the ladder. Of the 39 fish that were radio-tagged, 29 individuals were recorded approaching and ascending the ladder. The remaining fish either did not approach the dam (three fish), approached the dam after detailed tracking had ended (two fish), were recaptured by anglers (three fish), or the radio tags failed (two fish). Salmon released earlier in the year delayed longer before first approaching the dam. Delays between first approaching the dam and ascent of the ladder were greater for fish that approached the dam earlier. The majority of salmon visited the ladder entrance more than once (maximum 10 visits) before ascending. Having entered, all but four salmon ascended the fish ladder successfully on their first attempt. The four individuals that failed to do so succeeded on their second attempt. The rate at which salmon ascended the ladder was related directly to temperature. The shortest ascent time of a radio-tagged salmon was 5.25 h. Movements of eight of 11 tagged fish through the ladder ceased with the onset of darkness but continued on the following morning. No radio-tagged fish entered the ladder at temperatures below 9 o C. Similarly, few untagged fish were recorded ascending the ladder by the electronic fish counter at water temperatures below 8.5 o C. Records from the fish counter indicated that 92% of upstream movements were made during daylight. (author)

  2. Work-related falls from ladders--a follow-back study of US emergency department cases.

    Science.gov (United States)

    Lombardi, David A; Smith, Gordon S; Courtney, Theodore K; Brennan, Melanye J; Kim, Jae Young; Perry, Melissa J

    2011-11-01

    Ladder falls comprise 16% of all US workplace fall-related fatalities, and ladder use may be particularly hazardous among older workers. This follow-back study of injured workers from a nationally representative sample of US emergency departments (ED) focused on factors related to ladder falls in three domains of the work environment: work equipment, work practices, and worker-related factors. Risk factors for fractures, the most frequent and severe outcome, were also evaluated. Workers injured from a ladder fall, treated in one of the 65 participating ED in the occupational National Electronic Injury Surveillance System (NEISS) were asked to participate. The questionnaire included worker demographics, injury, ladder and work equipment and environment characteristics, work tasks, and activities. Multivariate logistic regression models estimated odds ratios and 95% confidence intervals of a work-related fracture. Three-hundred and six workers experiencing an injury from an--on average--7.5-foot-fall from a step, extension, or straight ladder were interviewed primarily from construction, installation, maintenance, and repair professions. Injuries were most frequently to the arm, elbow or shoulder; head, neck, or face with diagnoses were primarily fracture, strain, sprain, contusion or abrasion. Workers were most frequently standing or sitting on the ladder while installing, hanging an item, or performing a repair when they fell. Ladder movement was the mechanism in 40% of falls. Environmental conditions played a role in cases. There was a significant association between fracture risk and fall height while working on the ladder that was also influenced by older work age. This study advances knowledge of falls from ladders to support those who specify means and methods, select equipment, and plan, supervise, or manage the performance of employees working at heights.

  3. Dense zig-zag microstructures in YSZ thin films by pulsed laser deposition

    Science.gov (United States)

    Stender, Dieter; Schäuble, Nina; Weidenkaff, Anke; Montagne, Alex; Ghisleni, Rudy; Michler, Johann; Schneider, Christof W.; Wokaun, Alexander; Lippert, Thomas

    2015-01-01

    The very brittle oxygen ion conductor yttria stabilized zirconia (YSZ) is a typical solid electrolyte for miniaturized thin film fuel cells. In order to decrease the fuel cell operating temperature, the thickness of yttria stabilized zirconia thin films is reduced. Often, these thin membranes suffer from mechanical failure and gas permeability. To improve these mechanical issues, a glancing angle deposition approach is used to grow yttria stabilized zirconia thin films with tilted columnar structures. Changes of the material flux direction during the deposition result in a dense, zigzag-like structure with columnar crystallites. This structure reduces the elastic modulus of these membranes as compared to columnar yttria stabilized zirconia thin films as monitored by nano-indentation which makes them more adaptable to applied stress.

  4. Dense zig-zag microstructures in YSZ thin films by pulsed laser deposition

    Directory of Open Access Journals (Sweden)

    Dieter Stender

    2015-01-01

    Full Text Available The very brittle oxygen ion conductor yttria stabilized zirconia (YSZ is a typical solid electrolyte for miniaturized thin film fuel cells. In order to decrease the fuel cell operating temperature, the thickness of yttria stabilized zirconia thin films is reduced. Often, these thin membranes suffer from mechanical failure and gas permeability. To improve these mechanical issues, a glancing angle deposition approach is used to grow yttria stabilized zirconia thin films with tilted columnar structures. Changes of the material flux direction during the deposition result in a dense, zigzag-like structure with columnar crystallites. This structure reduces the elastic modulus of these membranes as compared to columnar yttria stabilized zirconia thin films as monitored by nano-indentation which makes them more adaptable to applied stress.

  5. Performance Comparison of Wireless Sensor Network Standard Protocols in an Aerospace Environment: ISA100.11a and ZigBee

    Science.gov (United States)

    Wagner, Raymond S.; Barton, Richard J.

    2011-01-01

    Wireless Sensor Networks (WSNs) can provide a substantial benefit in spacecraft systems, reducing launch weight and providing unprecedented flexibility by allowing instrumentation capabilities to grow and change over time. Achieving data transport reliability on par with that of wired systems, however, can prove extremely challenging in practice. Fortunately, much progress has been made in developing standard WSN radio protocols for applications from non-critical home automation to mission-critical industrial process control. The relative performances of candidate protocols must be compared in representative aerospace environments, however, to determine their suitability for spaceflight applications. In this paper, we will present the results of a rigorous laboratory analysis of the performance of two standards-based, low power, low data rate WSN protocols: ZigBee Pro and ISA100.11a. Both are based on IEEE 802.15.4 and augment that standard's specifications to build complete, multi-hop networking stacks. ZigBee Pro targets primarily the home and office automation markets, providing an ad-hoc protocol that is computationally lightweight and easy to implement in inexpensive system-on-a-chip components. As a result of this simplicity, however, ZigBee Pro can be susceptible to radio frequency (RF) interference. ISA100.11a, on the other hand, targets the industrial process control market, providing a robust, centrally-managed protocol capable of tolerating a significant amount of RF interference. To achieve these gains, a coordinated channel hopping mechanism is employed, which entails a greater computational complexity than ZigBee and requires more sophisticated and costly hardware. To guide future aerospace deployments, we must understand how well these standards relatively perform in analog environments under expected operating conditions. Specifically, we are interested in evaluating goodput -- application level throughput -- in a representative crewed environment

  6. Single-particle potential from resummed ladder diagrams

    International Nuclear Information System (INIS)

    Kaiser, N.

    2013-01-01

    A recent work on the resummation of fermionic in-medium ladder diagrams to all orders is extended by calculating the complex single-particle potential U(p, k f ) + i W(p, k f ) p > k f . The on-shell single-particle potential is constructed by means of a complex-valued in-medium loop that includes corrections from a test particle of momentum vector p added to the filled Fermi sea. The single-particle potential U(k f , k f ) at the Fermi surface as obtained from the resummation of the combined particle and hole ladder diagrams is shown to satisfy the Hugenholtz-Van-Hove theorem. The perturbative contributions at various orders a n in the scattering length are deduced and checked against the known analytical results at order a 1 and a 2 . The limit a → ∞ is studied as a special case and a strong momentum dependence of the real (and imaginary) single-particle potential is found. This feature indicates an instability against a phase transition to a state with an empty shell inside the Fermi sphere such that the density gets reduced by about 5%. The imaginary single-particle potential vanishes linearly at the Fermi surface. For comparison, the same analysis is performed for the resummed particle-particle ladder diagrams alone. In this truncation an instability for hole excitations near the Fermi surface is found at strong coupling. For the set of particle-hole ring diagrams the single-particle potential is calculated as well. Furthermore, the resummation of in-medium ladder diagrams to all orders is studied for a two-dimensional Fermi gas with a short-range two-body contact interaction. (orig.)

  7. Resposta morfogênica de embriões zigóticos de Erythrina velutina Willd: (Leguminosae cultivados in vitro

    Directory of Open Access Journals (Sweden)

    Priscila Tavares Fonseca

    2014-10-01

    Full Text Available O cultivo in vitro de embriões zigóticos é uma técnica promissora para se avançar no estudo do desenvolvimento embrionário e da quebra da dormência de sementes. Diante do exposto, objetivou-se, com este trabalho, avaliar o efeito dos reguladores vegetais 6-benzilaminopurina (BAP e ácido naftalenoacético (ANA no potencial morfogenético, in vitro, de embriões zigóticos de mulungu. Embriões zigóticos maduros, oriundos de sementes foram utilizados inteiros, ou seccionados em plúmula, região intermediária e radícula, sendo posteriormente inoculados em meio de cultura WPM, suplementado com combinações de BAP (0,0; 2,0; 4,0; 8,0; 12,0 e 16,0 µM e ANA (0,0; 1,0 e 2,0 µM, acrescido de 87,64 mM de sacarose e solidificado com 0,7% de ágar. Após 30 dias, avaliaram-se a percentagem de regeneração dos embriões e ápice plumular, o número de brotos, o número de folhas, o comprimento da parte aérea dos brotos, o número de raízes e a percentagem de formação de calos oriundos da região intermediária e da radícula. É possível a regeneração in vitro de mulungu, a partir dos explantes plúmula e embriões zigóticos inteiros, cultivados em meio de cultura WPM, suplementado com 4,0 µM de BAP. Regiões intermediárias e da radícula promoveram a formação de calos compactos (96,06%, na combinação de 10,63 µM BAP e 2,0 µM de ANA.

  8. Non-ladder extended renormalization group analysis of the dynamical chiral symmetry breaking

    Energy Technology Data Exchange (ETDEWEB)

    Aoki, Ken-Ichi; Takagi, Kaoru; Terao, Haruhiko; Tomoyose, Masashi [Kanazawa Univ., Inst. for Theoretical Physics, Kanazawa, Ishikawa (Japan)

    2000-04-01

    The order parameters of dynamical chiral symmetry breaking in QCD, the dynamical mass of quarks and the chiral condensates, are evaluated by numerically solving the non-perturbative renormalization group (NPRG) equations. We employ an approximation scheme beyond 'the ladder', that is, beyond the (improved) ladder Schwinger-Dyson equations. The chiral condensates are enhanced in comparison with the ladder approximation, which is phenomenologically favorable. The gauge dependence of the order parameters is reduced significantly in this scheme. (author)

  9. Non-ladder extended renormalization group analysis of the dynamical chiral symmetry breaking

    International Nuclear Information System (INIS)

    Aoki, Ken-Ichi; Takagi, Kaoru; Terao, Haruhiko; Tomoyose, Masashi

    2000-01-01

    The order parameters of dynamical chiral symmetry breaking in QCD, the dynamical mass of quarks and the chiral condensates, are evaluated by numerically solving the non-perturbative renormalization group (NPRG) equations. We employ an approximation scheme beyond 'the ladder', that is, beyond the (improved) ladder Schwinger-Dyson equations. The chiral condensates are enhanced in comparison with the ladder approximation, which is phenomenologically favorable. The gauge dependence of the order parameters is reduced significantly in this scheme. (author)

  10. Design and implementation of an IEEE 802.15.4/ZigBee based star network for data acquisition and monitoring

    International Nuclear Information System (INIS)

    Guha, S.K.; Nabhiraj, P.Y.; Bhaumik, T.K.; Mallik, C.

    2012-01-01

    ZigBee based wireless technology is used to provide a low cost, low power, secured, PAN solution for monitoring of parameters from several distributed vacuum pumping modules installed in the SCC injection line. The parameters include module's pump RPM, input current and pressure reading of different vacuum gauges. The ZigBee stack is written in a simplified form so that each node can create a network and can join to any established network when powered on. End nodes can be replaced through a little modification in the firmware codes. End node consists of sensors, signal conditioning circuits, microcontroller and ZigBee Transceiver whereas the Central node consists of microcontroller, Transceiver and UART interface. This paper highlights the future approach of utilizing this network for data acquisition related with environmental temperature, relative humidity, noise, water leakage from inaccessible areas of Cyclotron Vault, Pit, Basement and ECR Highbay for the ease of maintenance also the development of an environment monitoring system powered by solar cells covering a wide area. (author)

  11. Laddering em pesquisa de marketing

    Directory of Open Access Journals (Sweden)

    Tânia Modesto Veludo-de-Oliveira

    Full Text Available O artigo discute a técnica de pesquisa laddering em marketing, considerando a proposta de renovação de conhecimentos sobre metodologia na área. Para isso investiga diversos estudos, artigos e pesquisas que tratam do assunto em nível nacional e internacional. O conceito de cadeias meios-fins é abordado pela estrutura teórica que fundamenta a técnica, ligando atributos, conseqüências percebidas do consumo e valores pessoais relativos a um produto. O artigo segue com a explicação dos procedimentos de campo, como a entrevista e a análise dos dados. A laddering é um instrumento de pesquisa qualitativa bastante útil e poderoso, mas ainda pouco utilizado tanto por acadêmicos como por profissionais de mercado, no Brasil, provavelmente por desconhecimento e pouca divulgação. Cabe, portanto, uma maior disseminação de seu uso.

  12. Lattice architecture effect on the cooperativity of spin transition coordination polymers

    Energy Technology Data Exchange (ETDEWEB)

    Chiruta, Daniel [Faculty of Electrical Engineering and Computer Science and Advanced Materials and Nanotechnology Laboratory (AMNOL), Ştefan cel Mare University, Suceava 720229 (Romania); GEMaC, Université de Versailles Saint-Quentin-en-Yvelines, CNRS-UVSQ (UMR 8635), 78035 Versailles Cedex (France); LISV, Université de Versailles Saint-Quentin-en-Yvelines, 78140 Velizy (France); Jureschi, Catalin-Maricel; Rotaru, Aurelian, E-mail: jorge.linares@uvsq.fr, E-mail: rotaru@eed.usv.ro [Faculty of Electrical Engineering and Computer Science and Advanced Materials and Nanotechnology Laboratory (AMNOL), Ştefan cel Mare University, Suceava 720229 (Romania); Linares, Jorge, E-mail: jorge.linares@uvsq.fr, E-mail: rotaru@eed.usv.ro [GEMaC, Université de Versailles Saint-Quentin-en-Yvelines, CNRS-UVSQ (UMR 8635), 78035 Versailles Cedex (France); Garcia, Yann [Institute of Condensed Matter and Nanosciences, Molecules, Solids and Reactivity (IMCN/MOST), Université Catholique de Louvain, Place L. Pasteur, 1, 1348 Louvain-la-Neuve (Belgium)

    2014-02-07

    We have investigated in the framework of the Ising-like model, by means of Monte Carlo Metropolis method with open boundary condition, the architecture effect on the cooperativity of spin transition coordination polymers. We have analyzed the influence of several physical parameters (size, pressure, and edge effects) on different lattice architectures which were in good agreement with reported experimental data. We show that the cooperativity of a spin crossover system, characterized by the same number of molecules and the same short- and long-range interaction parameters, is progressively enhanced when going from a 1D chain to a 1D ladder type lattice and to a 2D square lattice.

  13. Optical characterisation of small surface targets

    CSIR Research Space (South Africa)

    Schwering, PBW

    2007-09-01

    Full Text Available , 3, 5 km distance from IMT (Institute for Maritime Technology) in Simon’ Town, in-bound head-on runs, as well as in-bound and out-bound weaving zig-zag runs. Target positions were accurately measured with a Differential GPS (DGPS) system. In some... to sea spray generated by the boat’s pitching action going through the sea swells (more pronounced at longer ranger). 4. BACKGROUND CLUTTER Of major interest in development of automatic detection and classification systems is the signal processing...

  14. Atomistic Simulations of Fluid Flow through Graphene Channels and Carbon Nanotubes

    DEFF Research Database (Denmark)

    Zambrano, Harvey A.; Walther, Jens Honore; Oyarzua, Elton E.

    2015-01-01

    conductivity, extremely low surface friction and superior mechanical properties, graphene channels and carbon nanotubes (CNTs) are promising candidates to be implemented as fluid conduits in nanosystems. Performing Non-equilibrium Molecular Dynamics simulations, we study the transport of water......-eletrolyte solutions inside single and multi-wall graphene channels and inside zig-zag and armchair CNTs of similar cross sectional area. In order to calibrate the force fields, we use dedicated criteria relevant to the hydrodynamics of the systems of interest. Different fluid driving mechanisms such as pressure...

  15. Pamięć o Zagładzie w perspektywie historyka teatru

    Directory of Open Access Journals (Sweden)

    Jacek Popiel

    2015-11-01

    Full Text Available In his Polski teatr Zagłady [The Polish Theater of the Holocaust], Grzegorz Niziołek, who starts with theater and specific theatrical performances and who focuses on artistic phenomena, presents problems that go far beyond art. This is a book that should be read by historians, literary scholars, political scientists and cultural experts. Sociologists and psychologists who study social behavior will also find some of its sections interesting. This Cracow theatrologist presents the extermination of Jews during the occupation of Poland as well as Polish-Jewish relations, i.e. one of the most difficult Polish problems, permeated with silence and resentment, in the form of a monograph and in relation to the history of post-war theater, of which it is an important part.

  16. Corrosion Control Specialist Career Ladder AFSC 53530, 53550, 53570, and 53690. Occupational Survey Report.

    Science.gov (United States)

    Air Force Occupational Measurement Center, Lackland AFB, TX.

    The report describes the results of a detailed occupational survey of the corrosion control career ladder. Responses to a 457-task, time rating inventory from 1,015 personnel (representing 64 percent of the career field) were analyzed to produce seven specific findings and the career ladder structure. The career ladder includes a variety of jobs…

  17. The chiral Ward-Takahashi identity in the ladder approximation

    International Nuclear Information System (INIS)

    Kugo, Taichiro; Mitchard, M.G.

    1992-01-01

    We show that the ladder approximation to the Schwinger-Dyson and Bethe-Salpeter equations preserves the Ward-Takahashi identity for the axial vector vertex if and only if we use the gluon momentum as the argument of the running coupling constant. However, in the usual Landau gauge this is inconsistent with the vector Ward identity. We propose a new method for making the ladder approximation scheme consistent with both vector and axial vector Ward identities. (orig.)

  18. Effect of relevant umklapp process on the two-leg Hubbard ladder with a half-filled band under pressure

    International Nuclear Information System (INIS)

    Haddad, S.; Bennaceur, R.

    1999-01-01

    By means of perturbative renormalization approach we study the effect of relevant umklapp process on dimensional crossover caused by interladder one particle hopping t bot in weakly coupled two-leg Hubbard ladders with a half filled-band. We found that a crossover takes place at a finite value t botc which increases as the amplitude of umklapp process increases. For t bot botc the system undergoes a phase transition to the spin density wave phase (SDW) via the two particle hopping process, while for t bot >t botc the system undergoes a crossover to the two dimensional Fermi liquid phase via one particle hopping process. (orig.)

  19. Dynamic parameterization and ladder operators for the Kratzer molecular potential

    International Nuclear Information System (INIS)

    Devi, O Babynanda; Singh, C Amuba

    2014-01-01

    Introducing independent parameters k and δ to represent the strength of the attractive and repulsive components, respectively, we write the Kratzer molecular potential as V(k,δ)=(ℏ 2 /2 m)(−k/r+δ(δ−1)/r 2 ). This parameterisation is not only natural, but also convenient for the construction of ladder operators for the system. Adopting the straightforward method of deriving recurrence relations among confluent hypergeometric functions, we construct seven pairs of ladder operators for the Kratzer potential system. Detailed analysis of the laddering actions of these operators is given to show that they connect eigenstates of equal energy but belong to a hierarchy of Kratzer potential systems corresponding to different values of the parameters k and δ. Significantly, it is pointed out that it may not be possible to construct, in the position representation, a ladder operator which would connect different eigenstates belonging to the same potential V(k,δ). Transition to the hydrogen atom case is discussed. A number (14 altogether) of functional relations among the confluent hypergeometric functions have been derived and reported separately in an appendix. (paper)

  20. Estimating Ladder Fuels: A New Approach Combining Field Photography with LiDAR

    Directory of Open Access Journals (Sweden)

    Heather A. Kramer

    2016-09-01

    Full Text Available Forests historically associated with frequent fire have changed dramatically due to fire suppression and past harvesting over the last century. The buildup of ladder fuels, which carry fire from the surface of the forest floor to tree crowns, is one of the critical changes, and it has contributed to uncharacteristically large and severe fires. The abundance of ladder fuels makes it difficult to return these forests to their natural fire regime or to meet management objectives. Despite the importance of ladder fuels, methods for quantifying them are limited and imprecise. LiDAR (Light Detection and Ranging, a form of active remote sensing, is able to estimate many aspects of forest structure across a landscape. This study investigates a new method for quantifying ladder fuel in the field (using photographs with a calibration banner and remotely (using LiDAR data. We apply these new techniques in the Klamath Mountains of Northern California to predict ladder fuel levels across the study area. Our results demonstrate a new utility of LiDAR data to identify fire hazard and areas in need of fuels reduction.

  1. Fabrication, characterization and some applications of graded chiral zigzag shaped nano-sculptured silver thin films

    Energy Technology Data Exchange (ETDEWEB)

    Savaloni, Hadi, E-mail: savaloni@khayam.ut.ac.ir [Department of Physics, University of Tehran, North-Kargar Street, Tehran (Iran, Islamic Republic of); Esfandiar, Ali [Department of Physics, University of Tehran, North-Kargar Street, Tehran (Iran, Islamic Republic of)

    2011-09-01

    Graded chiral zig-zag shaped nano-sculptured silver thin films (GCZSSTF) were produced in two stages using oblique deposition technique together with rotation of substrate about its surface normal while a shadowing block was also fixed at Center of the substrate holder. Chrystallographic and morphological structure of these films were obtained using X-ray diffraction (XRD) and atomic force microscopy (AFM). Spectrophotometry was used to obtain their optical behavior while their application in both hydrophobicity and gas sensing was also investigated. XRD results showed a dominant (1 1 1) orientation growth on the zig arm of the structure while by addition of the second arm (zag) the crystallographical growth orientation changed to (2 2 0). The anisotropic nano-structure of these films was also distinguished through (1 - R) spectra. A common peak at about 350 nm related to the TM mode of plasmon resonances and a broad shoulder at about 420 nm for the s-polarized light and at 620 nm for the p-polarized light corresponding to the LM mode of plasmon resonances are observed. These peaks are directly related to the nano-columns topography. The film system used here proved to act as a physical method for producing layer-by-layer structure for obtaining enhanced hydrophobic surfaces rather than the usual chemical methods reported in the literature. In addition, the GCZSSTF also acted as good as reported results for nano-tubes when applied as cathode in the field ionization gas sensing setup.

  2. Properties of Fe{sub 8−N}Co{sub N} nanoribbons and nanowires: A DFT approach

    Energy Technology Data Exchange (ETDEWEB)

    Muñoz, Francisco [Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle (Germany); Departamento de Física, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago 7800024 (Chile); Centro para el Desarrollo de la Nanociencia y la Nanotecnología, CEDENNA, Avda. Ecuador 3493, Santiago 9170124 (Chile); Altbir, D. [Centro para el Desarrollo de la Nanociencia y la Nanotecnología, CEDENNA, Avda. Ecuador 3493, Santiago 9170124 (Chile); Departamento de Física, Universidad de Santiago (Chile); Kiwi, Miguel, E-mail: m.kiwi.t@gmail.com [Departamento de Física, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago 7800024 (Chile); Centro para el Desarrollo de la Nanociencia y la Nanotecnología, CEDENNA, Avda. Ecuador 3493, Santiago 9170124 (Chile); Morán-López, J.L. [Departamento de Física, Laboratorio Interdisciplinario, Facultad de Ciencias, Universidad Nacional Autónoma de México, México, D.F. (Mexico)

    2013-08-15

    The structural configurations and magnetic properties of zig-zag nanoribbons and nanowires of Fe{sub 8−N}Co{sub N}, for 0≤N≤8, are calculated within the density functional theory. Both, for the zig-zag nanoribbons and the nanowires, there is a tendency towards forming Fe–Co bonds, while segregation of the Fe and Co is energetically unfavorable. For the nanowire structures a transition from bcc Fe to hcp Co spatial arrangements is observed when N is increased from 4 to 6, in spite of the small size of the systems under investigation. The energy minimization was performed taking into consideration the electronic and magnetic structures, since for each crystalline structure, chemical composition, and short range order, particular magnetic properties of these systems do correspond. The magnetocrystalline anisotropy energy is calculated, and it is found that the easy axis changes from a transverse direction in Fe-rich systems, to the axial direction as the Co concentration increases. It is also found that although there are important variations of the local magnetic moment of the components, and their particular location in the system, the average magnetic moment is an almost linear function of N. - Highlights: ► Properties of Fe{sub 8−N}Co{sub N} nanoribbons and nanowires are calculated ab initio. ► Structural and magnetic properties of nanoribbons and nanowires are calculated. ► Shape and crystalline anisotropies of nanoribbons and nanowires are contrasted.

  3. Evaluation through research of a three-track career ladder program for registered nurses.

    Science.gov (United States)

    Korman, Carol; Eliades, Aris Beoglos

    2010-01-01

    A descriptive study design was employed to survey registered nurse participants in a career ladder program comprising of three tracks: clinical, education, and management. Findings indicate that participation allows nurses of varying education preparation and roles to demonstrate professional development. Implications for staff development include efficacy of the online survey technique, provision of a reliable tool to evaluate a career ladder, and evaluation of a career ladder that includes the staff development educator.

  4. Dissipation, Voltage Profile and Levy Dragon in a Special Ladder Network

    Science.gov (United States)

    Ucak, C.

    2009-01-01

    A ladder network constructed by an elementary two-terminal network consisting of a parallel resistor-inductor block in series with a parallel resistor-capacitor block sometimes is said to have a non-dispersive dissipative response. This special ladder network is created iteratively by replacing the elementary two-terminal network in place of the…

  5. Convergence and periodic solutions for the input impedance of a standard ladder network

    International Nuclear Information System (INIS)

    Ucak, C; Acar, C

    2007-01-01

    The input impedance of an infinite ladder network is computed by using the recursive relation and by assuming that the input impedance does not change when a new block is added to the network. However, this assumption is not true in general and standard textbooks do not always treat these networks correctly. This paper develops a general solution to obtain the input impedance of a standard ladder network of impedances and admittances for any number of blocks. Then, this result is used to provide the convergence condition for the infinite ladder network. The conditions which lead to periodic input impedance are exploited. It is shown that there are infinite numbers of periodic points and no paradoxical behaviour exists in the standard ladder network

  6. A Review and Modern Approach to LC Ladder Synthesis

    Directory of Open Access Journals (Sweden)

    Alexander J. Casson

    2011-01-01

    Full Text Available Ultra low power circuits require robust and reliable operation despite the unavoidable use of low currents and the weak inversion transistor operation region. For analogue domain filtering doubly terminated LC ladder based filter topologies are thus highly desirable as they have very low sensitivities to component values: non-exact component values have a minimal effect on the realised transfer function. However, not all transfer functions are suitable for implementation via a LC ladder prototype, and even when the transfer function is suitable the synthesis procedure is not trivial. The modern circuit designer can thus benefit from an updated treatment of this synthesis procedure. This paper presents a methodology for the design of doubly terminated LC ladder structures making use of the symbolic maths engines in programs such as MATLAB and MAPLE. The methodology is explained through the detailed synthesis of an example 7th order bandpass filter transfer function for use in electroencephalogram (EEG analysis.

  7. Controlled parity switch of persistent currents in quantum ladders

    Science.gov (United States)

    Filippone, Michele; Bardyn, Charles-Edouard; Giamarchi, Thierry

    2018-05-01

    We investigate the behavior of persistent currents for a fixed number of noninteracting fermions in a periodic quantum ladder threaded by Aharonov-Bohm and transverse magnetic fluxes Φ and χ . We show that the coupling between ladder legs provides a way to effectively change the ground-state fermion-number parity, by varying χ . Specifically, we demonstrate that varying χ by 2 π (one flux quantum) leads to an apparent fermion-number parity switch. We find that persistent currents exhibit a robust 4 π periodicity as a function of χ , despite the fact that χ →χ +2 π leads to modifications of order 1 /N of the energy spectrum, where N is the number of sites in each ladder leg. We show that these parity-switch and 4 π periodicity effects are robust with respect to temperature and disorder, and outline potential physical realizations using cold atomic gases and photonic lattices, for bosonic analogs of the effects.

  8. USAR Robot Communication Using ZigBee Technology

    Science.gov (United States)

    Tsui, Charles; Carnegie, Dale; Pan, Qing Wei

    This paper reports the successful development of an automatic routing wireless network for USAR (urban search and rescue) robots in an artificial rubble environment. The wireless network was formed using ZigBee modules and each module was attached to a micro-controller in order to model a wireless USAR robot. Proof of concept experiments were carried out by deploying the networked robots into artificial rubble. The rubble was simulated by connecting holes and trenches that were dug in 50 cm deep soil. The simulated robots were placed in the bottom of the holes. The holes and trenches were then covered up by various building materials and soil to simulate a real rubble environment. Experiments demonstrated that a monitoring computer placed 10 meters outside the rubble can establish proper communication with all robots inside the artificial rubble environment.

  9. Design of the smart home system based on the optimal routing algorithm and ZigBee network.

    Directory of Open Access Journals (Sweden)

    Dengying Jiang

    Full Text Available To improve the traditional smart home system, its electric wiring, networking technology, information transmission and facility control are studied. In this paper, we study the electric wiring, networking technology, information transmission and facility control to improve the traditional smart home system. First, ZigBee is used to replace the traditional electric wiring. Second, a network is built to connect lots of wireless sensors and facilities, thanks to the capability of ZigBee self-organized network and Genetic Algorithm-Particle Swarm Optimization Algorithm (GA-PSOA to search for the optimal route. Finally, when the smart home system is connected to the internet based on the remote server technology, home environment and facilities could be remote real-time controlled. The experiments show that the GA-PSOA reduce the system delay and decrease the energy consumption of the wireless system.

  10. Design of the smart home system based on the optimal routing algorithm and ZigBee network.

    Science.gov (United States)

    Jiang, Dengying; Yu, Ling; Wang, Fei; Xie, Xiaoxia; Yu, Yongsheng

    2017-01-01

    To improve the traditional smart home system, its electric wiring, networking technology, information transmission and facility control are studied. In this paper, we study the electric wiring, networking technology, information transmission and facility control to improve the traditional smart home system. First, ZigBee is used to replace the traditional electric wiring. Second, a network is built to connect lots of wireless sensors and facilities, thanks to the capability of ZigBee self-organized network and Genetic Algorithm-Particle Swarm Optimization Algorithm (GA-PSOA) to search for the optimal route. Finally, when the smart home system is connected to the internet based on the remote server technology, home environment and facilities could be remote real-time controlled. The experiments show that the GA-PSOA reduce the system delay and decrease the energy consumption of the wireless system.

  11. Probing the sky with radio waves from wireless technology to the development of atmospheric science

    CERN Document Server

    Yeang, Chen-Pang

    2013-01-01

    By the late nineteenth century, engineers and experimental scientists generally knew how radio waves behaved, and by 1901 scientists were able to manipulate them to transmit messages across long distances. What no one could understand, however, was why radio waves followed the curvature of the Earth. Theorists puzzled over this for nearly twenty years before physicists confirmed the zig-zag theory, a solution that led to the discovery of a layer in the Earth's upper atmosphere that bounces radio waves earthward-the ionosphere. In Probing the Sky with Radio Waves,

  12. Design windows of laser fusion power plants and conceptual design of laser-diode pumped slab laser

    International Nuclear Information System (INIS)

    Kozaki, Y.; Eguchi, T.; Izawa, Y.

    1999-01-01

    An analysis of the design space available to laser fusion power plants has been carried out, in terms of design key parameters such as target gain, laser energy and laser repetition rate, the number of fusion react ion chambers, and plant size. The design windows of economically attractive laser fusion plants is identified with the constraints of key design parameters and the cost conditions. Especially, for achieving high repetition rate lasers, we have proposed and designed a diode-pumped solid-state laser driver which consists of water-cooled zig-zag path slab amplifiers. (author)

  13. Flowing Air-Water Cooled Slab Nd: Glass Laser

    Science.gov (United States)

    Lu, Baida; Cai, Bangwei; Liao, Y.; Xu, Shifa; Xin, Z.

    1989-03-01

    A zig-zag optical path slab geometry Nd: glass laser cooled through flowing air-water is developed by us. Theoretical studies on temperature distribution of slab and rod configurations in the unsteady state clarify the advantages of the slab geometry laser. The slab design and processing are also reported. In our experiments main laser output characteristics, e. g. laser efficiency, polarization, far-field divergence angle as well as resonator misalignment are investigated. The slab phosphate glass laser in combination with a crossed Porro-prism resonator demonstrates a good laser performance.

  14. Application of Elliptic Curve Cryptography in ZigBee Wireless Sensor Network

    Directory of Open Access Journals (Sweden)

    Feng Xu

    2013-05-01

    Full Text Available An encryption algorithm is the core of network security, but for ZigBee wireless sensor network (WSN, the complexity of this algorithm directly affects the cost and energy consumption in MCU hardware storage resources, which results in confliction between data protection and overhead. In this paper, a contradiction simple elliptic curve cryptosystem (ECC is proposed to use for terminal nodes and host computer for data encryption and authentication, the purpose is to save the hardware cost and enhanced data security.

  15. The Design and Implementation of Smart Monitoring System for Large-Scale Railway Maintenance Equipment Cab Based on ZigBee Wireless Sensor Network

    Directory of Open Access Journals (Sweden)

    Hairui Wang

    2014-06-01

    Full Text Available In recent years, organizations use IEEE 802.15.4 and ZigBee technology to deliver solution in variety areas including home environment monitoring. ZigBee technology has advantages on low-cost, low power consumption and self-forming. With the rapid expansion of the Internet, there is the requirement for remote monitoring large-scale railway maintenance equipment cab. This paper discusses the disadvantages of the existing smart monitoring system, and proposes a solution. A ZigBee wireless sensor network smart monitoring system and Wi-Fi network is integrated through a home gateway to increase the system flexibility. At the same time the home gateway cooperated with a pre- processing system provide a flexible user interface, and the security and safety of the smart monitoring system. To testify the efficiency of the proposed system, the temperature and humidity sensors and light sensors have developed and evaluated in the smart monitoring system.

  16. Análisis de la fuerza isométrica en la propulsión y tracción en slalom en silla de ruedas y su relación con el rendimiento y la clasificación funcional. [Isometric force in wheelchair slalom during traction and propulsion and their relationship with performance and functional classification].

    Directory of Open Access Journals (Sweden)

    Raúl Reina

    2013-10-01

    Full Text Available El sistema de clasificación del slalom en silla de ruedas contempla como elegibles a deportistas con parálisis cerebral y daño cerebral adquirido. La tendencia actual en los sistemas de clasificación es realizar una clasificación integrada y funcional basada en evidencias científicas. En este estudio participaron 9 deportistas (21,2 ± 4,7 años de nivel nacional con parálisis cerebral (5 ♂ y 4 ♀ de las divisiones D2, D3 y D4, relacionadas con los perfiles funcionales de la Cerebral Palsy International Sports and Recreation Association. Se realizaron dos pruebas de fuerza máxima isométrica (propulsión y tracción sobre la silla de competición, donde se midió fuerza máxima (Fmax, fuerza media (Fmed, tiempo de ejecución y tiempo hasta diferentes porcentajes de Fmax. Además, se realizaron dos pruebas de rendimiento específicas: 16 m de desplazamiento lineal con una puerta de inversión situada a 8; y dos desplazamientos lineales de 4 m, realizando un zig-zag de ida y vuelta entre ambos, registrando el tiempo de ejecución con un sistema de cronometraje electrónico. Se encontraron diferencias estadísticamente significativas en las pruebas de propulsión entre los deportistas de D3 y D4 para la Fmax (p = 0,007 y Fmed (p = 0,002, siendo mayores los valores de esta última. En las pruebas de rendimiento específico, se encontraron diferencias entre D2 y D3 (inversión: p = 0,034 y zig-zag: p = 0,010, siendo menores los tiempos de D3. Los resultados muestran que no hay una relación lineal entre las divisiones y el rendimiento mostrado. AbstractAthletes with cerebral palsy and acquired cerebral damage are eligible for competition according to the wheelchair slalom classification system. The current trend in the classification systems is to perform an integrated and functional classification based on scientific evidence. Nine national level wheelchair slalom athletes (21,2 ± 4,7 years from D2, D3 and D4 divisions, as per functional

  17. Performance Comparison of Wireless Sensor Network Standard Protocols in an Aerospace Environment: ISA100.11a and ZigBee Pro

    Science.gov (United States)

    Wagner, Raymond S.; Barton, Richard J.

    2011-01-01

    Standards-based wireless sensor network (WSN) protocols are promising candidates for spacecraft avionics systems, offering unprecedented instrumentation flexibility and expandability. Ensuring reliable data transport is key, however, when migrating from wired to wireless data gathering systems. In this paper, we conduct a rigorous laboratory analysis of the relative performances of the ZigBee Pro and ISA100.11a protocols in a representative crewed aerospace environment. Since both operate in the 2.4 GHz radio frequency (RF) band shared by systems such as Wi-Fi, they are subject at times to potentially debilitating RF interference. We compare goodput (application-level throughput) achievable by both under varying levels of 802.11g Wi-Fi traffic. We conclude that while the simpler, more inexpensive ZigBee Pro protocol performs well under moderate levels of interference, the more complex and costly ISA100.11a protocol is needed to ensure reliable data delivery under heavier interference. This paper represents the first published, rigorous analysis of WSN protocols in an aerospace environment that we are aware of and the first published head-to-head comparison of ZigBee Pro and ISA100.11a.

  18. The design of the CMOS wireless bar code scanner applying optical system based on ZigBee

    Science.gov (United States)

    Chen, Yuelin; Peng, Jian

    2008-03-01

    The traditional bar code scanner is influenced by the length of data line, but the farthest distance of the wireless bar code scanner of wireless communication is generally between 30m and 100m on the market. By rebuilding the traditional CCD optical bar code scanner, a CMOS code scanner is designed based on the ZigBee to meet the demands of market. The scan system consists of the CMOS image sensor and embedded chip S3C2401X, when the two dimensional bar code is read, the results show the inaccurate and wrong code bar, resulted from image defile, disturber, reads image condition badness, signal interference, unstable system voltage. So we put forward the method which uses the matrix evaluation and Read-Solomon arithmetic to solve them. In order to construct the whole wireless optics of bar code system and to ensure its ability of transmitting bar code image signals digitally with long distances, ZigBee is used to transmit data to the base station, and this module is designed based on image acquisition system, and at last the wireless transmitting/receiving CC2430 module circuit linking chart is established. And by transplanting the embedded RTOS system LINUX to the MCU, an applying wireless CMOS optics bar code scanner and multi-task system is constructed. Finally, performance of communication is tested by evaluation software Smart RF. In broad space, every ZIGBEE node can realize 50m transmission with high reliability. When adding more ZigBee nodes, the transmission distance can be several thousands of meters long.

  19. ABC of ladder operators for rationally extended quantum harmonic oscillator systems

    Science.gov (United States)

    Cariñena, José F.; Plyushchay, Mikhail S.

    2017-07-01

    The problem of construction of ladder operators for rationally extended quantum harmonic oscillator (REQHO) systems of a general form is investigated in the light of existence of different schemes of the Darboux-Crum-Krein-Adler transformations by which such systems can be generated from the quantum harmonic oscillator. Any REQHO system is characterized by the number of separated states in its spectrum, the number of ‘valence bands’ in which the separated states are organized, and by the total number of the missing energy levels and their position. All these peculiarities of a REQHO system are shown to be detected and reflected by a trinity (A^+/- , B^+/- , C^+/-) of the basic (primary) lowering and raising ladder operators related between themselves by certain algebraic identities with coefficients polynomially-dependent on the Hamiltonian. We show that all the secondary, higher-order ladder operators are obtainable by a composition of the basic ladder operators of the trinity which form the set of the spectrum-generating operators. Each trinity, in turn, can be constructed from the intertwining operators of the two complementary minimal schemes of the Darboux-Crum-Krein-Adler transformations.

  20. 29 CFR 1910.27 - Fixed ladders.

    Science.gov (United States)

    2010-07-01

    ...) All rungs shall have a minimum diameter of three-fourths inch for metal ladders, except as covered in... appurtenances shall be painted or otherwise treated to resist corrosion and rusting when location demands... areas under floors, are frequently located in an atmosphere that causes corrosion and rusting. To...

  1. Hadron structure in the ladder model

    International Nuclear Information System (INIS)

    Soper, D.E.

    1979-01-01

    The (flavor non-singlet) Green's function to find a far-off-shell quark in a hadron is obtained in the renormalization group improved ladder model for QCD in the space-like axial gauge. Particular attention is paid to the role of the singularity in the gluon propagator. 4 figures

  2. Laughlin-like States in Bosonic and Fermionic Atomic Synthetic Ladders

    Directory of Open Access Journals (Sweden)

    Marcello Calvanese Strinati

    2017-06-01

    Full Text Available The combination of interactions and static gauge fields plays a pivotal role in our understanding of strongly correlated quantum matter. Cold atomic gases endowed with a synthetic dimension are emerging as an ideal platform to experimentally address this interplay in quasi-one-dimensional systems. A fundamental question is whether these setups can give access to pristine two-dimensional phenomena, such as the fractional quantum Hall effect, and how. We show that unambiguous signatures of bosonic and fermionic Laughlin-like states can be observed and characterized in synthetic ladders. We theoretically diagnose these Laughlin-like states focusing on the chiral current flowing in the ladder, on the central charge of the low-energy theory, and on the properties of the entanglement entropy. Remarkably, Laughlin-like states are separated from conventional liquids by Lifschitz-type transitions, characterized by sharp discontinuities in the current profiles, which we address using extensive simulations based on matrix-product states. Our work provides a qualitative and quantitative guideline towards the observability and understanding of strongly correlated states of matter in synthetic ladders. In particular, we unveil how state-of-the-art experimental settings constitute an ideal starting point to progressively tackle two-dimensional strongly interacting systems from a ladder viewpoint, opening a new perspective for the observation of non-Abelian states of matter.

  3. Frustrated S = 1/2 Two-Leg Ladder with Different Leg Interactions

    Science.gov (United States)

    Tonegawa, Takashi; Okamoto, Kiyomi; Hikihara, Toshiya; Sakai, Tôru

    2017-04-01

    We explore the ground-state phase diagram of the S = 1/2 two-leg ladder. The isotropic leg interactions J1,a and J1,b between nearest neighbor spins in the legs a and b, respectively, are different from each other. The xy and z components of the uniform rung interactions are denoted by Jr and ΔJr, respectively, where Δ is the XXZ anisotropy parameter. This system has a frustration when J1,aJ1,b employ the physical consideration, the level spectroscopy analysis of the results obtained by the exact diagonalization method and also the density-matrix renormalization-group method. It is found that the non-collinear ferrimagnetic (NCFR) state appears as the ground state in the frustrated region of the parameters. Furthermore, the direct-product triplet-dimer (TD) state in which all rungs form the TD pair is the exact ground state, when J1,a + J1,b = 0 and 0≤ Δ ≲ 0.83. The obtained phase diagrams consist of the TD, XY and Haldane phases as well as the NCFR phase.

  4. DUNDRUM Restriction-Intrusion of Liberty Ladders (DRILL) Audit Toolkit

    LENUS (Irish Health Repository)

    Kennedy, Harry G

    2011-09-01

    This series of rating \\'ladders\\' is intended to allow a quantitative and qualitative analysis of the use of restrictive and intrusive interventions as part of the therapeutic management of violence and aggression in psychiatric hospital settings. This is an evolving handbook. The ladders are currently organised to facilitate a behavioural analysis. Context, antecedents, behaviour, interventions, consequences are conceptualised as a series of events organised in temporal sequence so that causes, interactions and effects can be considered. The complexity of analysis possible is limited by the statistical power of the numbers of cases and events available. \\r\

  5. A Continuous Game of Sankes and Ladders

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 14; Issue 8. The Control of Tuberculosis: A Continuous Game of Sankes and Ladders. T Ramakrishnan P Chandrasekhar. Classics Volume 14 Issue 8 August 2009 pp 820-834 ...

  6. Cavity-induced artificial gauge field in a Bose-Hubbard ladder

    Science.gov (United States)

    Halati, Catalin-Mihai; Sheikhan, Ameneh; Kollath, Corinna

    2017-12-01

    We consider theoretically ultracold interacting bosonic atoms confined to quasi-one-dimensional ladder structures formed by optical lattices and coupled to the field of an optical cavity. The atoms can collect a spatial phase imprint during a cavity-assisted tunneling along a rung via Raman transitions employing a cavity mode and a transverse running wave pump beam. By adiabatic elimination of the cavity field we obtain an effective Hamiltonian for the bosonic atoms, with a self-consistency condition. Using the numerical density-matrix renormalization-group method, we obtain a rich steady-state diagram of self-organized steady states. Transitions between superfluid to Mott-insulating states occur, on top of which we can have Meissner, vortex liquid, and vortex lattice phases. Also a state that explicitly breaks the symmetry between the two legs of the ladder, namely, the biased-ladder phase, is dynamically stabilized. We investigate the influence that a trapping potential has on the stability of the self-organized phases.

  7. IEEE 802154 and ZigBee as enabling technologies for low-power wireless systems with quality-of-service constraints

    CERN Document Server

    Tennina, Stefano; Daidone, Roberta; Alves, Mário; Jurčík, Petr; Severino, Ricardo; Tiloca, Marco; Hauer, Jan-Hinrich; Pereira, Nuno; Dini, Gianluca; Bouroche, Mélanie; Tovar, Eduardo

    2013-01-01

    This book outlines the most important characteristics of IEEE 802.15.4 and ZigBee and how they can be used to engineer Wireless Sensor Network (WSN) systems and applications, with a particular focus on Quality-of-Service (QoS) aspects. It starts by providing a snapshot of the most relevant features of these two protocols, identifying some gaps in the standard specifications. Then it describes several state-of-the-art open-source implementations, models and tools that have been designed by the authors and have been widely used by the international community. The book also outlines the fundamental performance limits of IEEE 802.15.4/ZigBee networks, based on well-sustained analytical, simulation and experimental models, including how to dimension such networks to optimize delay/energy trade-offs.

  8. Implementation of a wireless ECG acquisition SoC for IEEE 802.15.4 (ZigBee) applications.

    Science.gov (United States)

    Wang, Liang-Hung; Chen, Tsung-Yen; Lin, Kuang-Hao; Fang, Qiang; Lee, Shuenn-Yuh

    2015-01-01

    This paper presents a wireless biosignal acquisition system-on-a-chip (WBSA-SoC) specialized for electrocardiogram (ECG) monitoring. The proposed system consists of three subsystems, namely, 1) the ECG acquisition node, 2) the protocol for standard IEEE 802.15.4 ZigBee system, and 3) the RF transmitter circuits. The ZigBee protocol is adopted for wireless communication to achieve high integration, applicability, and portability. A fully integrated CMOS RF front end containing a quadrature voltage-controlled oscillator and a 2.4-GHz low-IF (i.e., zero-IF) transmitter is employed to transmit ECG signals through wireless communication. The low-power WBSA-SoC is implemented by the TSMC 0.18-μm standard CMOS process. An ARM-based displayer with FPGA demodulation and an RF receiver with analog-to-digital mixed-mode circuits are constructed as verification platform to demonstrate the wireless ECG acquisition system. Measurement results on the human body show that the proposed SoC can effectively acquire ECG signals.

  9. Estimating ladder fuels: a new approach combining field photography with LiDAR

    Science.gov (United States)

    Heather Kramer; Brandon Collins; Frank Lake; Marek Jakubowski; Scott Stephens; Maggi Kelly

    2016-01-01

    Forests historically associated with frequent fire have changed dramatically due to fire suppression and past harvesting over the last century. The buildup of ladder fuels, which carry fire from the surface of the forest floor to tree crowns, is one of the critical changes, and it has contributed to uncharacteristically large and severe fires. The abundance of ladder...

  10. Light-cone gauge approach to arbitrary spin fields, currents and shadows

    International Nuclear Information System (INIS)

    Metsaev, R R

    2014-01-01

    Totally symmetric arbitrary spin fields in AdS space, conformal fields, conformal currents, and shadow fields in flat space are studied. Light-cone gauge formulations for such fields, currents and shadows are obtained. Use of the Poincaré parametrization of AdS space and ladder operators allows us to treat fields in flat and AdS spaces on an equal footing. Light-cone gauge realization of relativistic symmetries for fields, currents and shadows is also obtained. The light-cone gauge formulation for fields is obtained by using the gauge invariant Lagrangian which is presented in terms of modified de Donder divergence, while the light-cone gauge formulation for currents and shadows is obtained by using the gauge invariant approach to currents and shadows. This allows us to demonstrate explicitly how the ladder operators entering the gauge invariant formulation of fields, currents and shadows manifest themselves in the light-cone gauge formulation for fields, currents and shadows. (paper)

  11. Synthesis, structural characterization and photoluminescent properties of 2D multilayer Cu+ coordination polymers via Csbnd H⋯π and π⋯π interactions

    Science.gov (United States)

    Huang, Ting-Hong; Zhu, Sheng-Lan; Xiong, Xian-Lian; Li, Jia-Dong; Yang, Hu; Huang, Xin; Huang, Xue-Ren; Zhang, Kunming

    2017-09-01

    Two Cu(I) coordination polymers, {[Cu(pmbb)0.5(4,4'-bipy)0.5(PPh3)](BF4) (H2O)2}n (1) and {[Cu(pmbb)0.5(bpe)0.5(PPh3)](BF4)(DMF)}n (2) (pmbb = N, N'-bis(pyridin-2-ylmethylene)biphenyl -4,4'-diamine, 4,4'-bipy = 4,4'-bipyridine, bpe = 1,2-bis(4-pyridyl)ethylene), PPh3 = triphenyl phosphine), have been synthesized and characterized by IR, 1H NMR, 13C NMR, 31P NMR, 19F NMR, 11B-NMR, TG and X-ray crystal structure analysis. The structural analysis shows that complexes 1 and 2 contain diverse and interesting 2D supramolecular networks based on inter-chain interactions. Complex 1 displays a 1D zig-zag chain and a 1D+1D→2D supramolecular network formed by intermolecular Csbnd H···π interaction. For 2, each 1D zig-zag chain interacts with neighboring ones via intermolecular Csbnd H···π and π···π stacking interactions, leading to the formation of a 2D-stacking network. Furthermore, solid-state UV-Vis absorption spectra of complexes 1 and 2 indicate the existence of MLCT absorption. Complexes 1 and 2 show efficient luminescent emission peaks at 435 and 452 nm assigned to MLCT excited states, and the emission decay lifetimes are 20.82 μs for 1 and 20.72 μs for 2, displaying strong room-temperature solid-state photoluminescence. Moreover, thermogravimetric analysis shows that the heat stability of polymers is 1>2.

  12. Solvent induced synthesis, structure and properties of coordination polymers based on 5-hydroxyisophthalic acid as linker and 1,10-phenanthroline as auxiliary ligand

    International Nuclear Information System (INIS)

    Kariem, Mukaddus; Yawer, Mohd; Sheikh, Haq Nawaz

    2015-01-01

    Three new coordination polymers [Mn(hip)(phen) (H_2O)]_n (1), [Co(hip)(phen) (H_2O)]_n (2), and [Cd(hip) (phen) (H_2O)]_n (3) (H_2hip=5-hydroxyisophthalic acid; phen=1,10-phenanthroline) have been synthesized by solvo-hydrothermal method using diethyl formamide-water (DEF-H_2O) as solvent system. Single-crystal X-ray diffraction analysis reveals that all three coordination polymers 1, 2 and 3 crystallize in monoclinic space group P2/n. Metal ions are inter-connected by hydroxyisophthalate anions forming zig-zag 1D chain. 1D chains are further inter-connected by hydrogen bonding and π–π stacking interactions leading to 3D supramolecular architecture. Hydrogen-bonding and π–π stacking provide thermal stability to polymers. Compounds 1 and 2 are paramagnetic at room temperature and variable temperature magnetic moment measurements revealed weak ferromagnetic interactions between metal ions at low temperature. Compound 3 exhibits excellent photoluminescence with large Stokes shift. - Graphical abstract: 1D helical chains of coordination polymers were synthesized by solvo-hydrothermal reaction of 5-hydroxyisopthalic acid and 1,10-phenanthroline with MnCl_2·4H_2O / CoCl_2·6H_2O / Cd(NO_3)_2·6H_2O. - Highlights: • Solvent induced synthesis of three coordination polymers with 1D zig-zag structure. • Crystal structures of coordination polymers are reported and discussed. • 1,10-Phenanthroline influences magnetic and luminescent properties of polymers. • Coordination polymer of Cd is luminescent exhibiting large Stokes shift.

  13. Strength Analysis on Ship Ladder Using Finite Element Method

    Science.gov (United States)

    Budianto; Wahyudi, M. T.; Dinata, U.; Ruddianto; Eko P., M. M.

    2018-01-01

    In designing the ship’s structure, it should refer to the rules in accordance with applicable classification standards. In this case, designing Ladder (Staircase) on a Ferry Ship which is set up, it must be reviewed based on the loads during ship operations, either during sailing or at port operations. The classification rules in ship design refer to the calculation of the structure components described in Classification calculation method and can be analysed using the Finite Element Method. Classification Regulations used in the design of Ferry Ships used BKI (Bureau of Classification Indonesia). So the rules for the provision of material composition in the mechanical properties of the material should refer to the classification of the used vessel. The analysis in this structure used program structure packages based on Finite Element Method. By using structural analysis on Ladder (Ladder), it obtained strength and simulation structure that can withstand load 140 kg both in static condition, dynamic, and impact. Therefore, the result of the analysis included values of safety factors in the ship is to keep the structure safe but the strength of the structure is not excessive.

  14. Triptycene-based ladder monomers and polymers, methods of making each, and methods of use

    KAUST Repository

    Pinnau, Ingo; Ghanem, Bader; Swaidan, Raja

    2015-01-01

    Embodiments of the present disclosure provide for a triptycene-based A-B monomer, a method of making a triptycene-based A-B monomer, a triptycene-based ladder polymer, a method of making a triptycene-based ladder polymers, a method of using

  15. Using career ladders to motivate and retain employees: an implementation success story.

    Science.gov (United States)

    Garletts, Joseph A

    2002-01-01

    In October 2000, Phoenix-based Sonora Quest Laboratories, LLC (SQL), commissioned The Gelfond Group to survey SQL employees. Responding to negative survey scores, SQL developed and implemented an entry-level career ladder for line staff of the specimen management/referral testing department. The program was piloted in February 2001, and was implemented fully shortly thereafter. The ladder was designed to provide job enrichment opportunities through company-conducted training and advancement provisions. It contained requirements for productivity and quality of work performed in addition to increasingly rigorous training and competency documentation. Employees were accountable for their own advancement and for ensuring that all documentation was complete. Advancement was automatic once requirements were completed. Pay increases accompanied each advancement on a predetermined scale. At the end of 12 months, employee turnover dropped from 39% to less than 20% annually. Both productivity and morale improved, and results on a second employee survey indicated dramatic improvement in five key areas. The career ladder concept has been replicated successfully in several other departments, including phlebotomy, and a six-tiered ladder is under development for the clinical laboratory. It will encompass CLA, MLT, and MT positions from entry level to technical coordinator.

  16. Crystalline roof glazing - Westside shopping centre, Berne; Kristalline Dachverglasungen

    Energy Technology Data Exchange (ETDEWEB)

    Enkerli, W.

    2009-07-01

    This illustrated article takes a look at the new shopping and leisure centre on the western outskirts of Berne, Switzerland. In particular, the roof of this unusual building over the motorway with its sloping walls and zig-zag design is looked at. The centre's shopping mall, adventure baths and spa, a multiplex cinema, an old peoples' home and a hotel are briefly discussed, as is the embedding of the centre in its suburban environment. The roof construction with its crystalline skylights is examined and discussed in detail. The centre's building technical services are also briefly commented on.

  17. Climate and humans set the place and time of Proboscidean extinction in late Quaternary of South America

    DEFF Research Database (Denmark)

    Lima-Ribeiro, Matheus Souza; Nogues, David Bravo; Terribile, Levi Carina

    2013-01-01

    of human hunting, but if climatic conditions were suitable like in Last Glacial Maximum (LGM), the time-for-extinction would be at least 3 times longer under the same human hunting pressures. Thus, our findings support the ``Broken Zig-Zag'' model and show that South American Proboscideans might have been...... (ENMs) and modeled the timing for extinction under human hunting scenario, and both variables were used to explain the extinction dynamics of Proboscideans during a full interglacial/glacial cycle (from 126 ka to 6 ka) in South America. We found a large contraction in the geographic range size of two...

  18. 1995 Edward teller lecture. Patience and optimism

    International Nuclear Information System (INIS)

    Miley, G.H.

    1996-01-01

    Remarks made in the author close-quote s acceptance lecture for the 1995 Edward Teller Medal are presented and expanded. Topics covered include research on nuclear-pumped lasers, the first direct e-beam-pumped laser, direct energy conversion and advanced fuel fusion, plus recent work on inertial electrostatic confinement. open-quote open-quote Patience close-quote close-quote and open-quote open-quote optimism close-quote close-quote are viewed as essential elements needed by scientists following the open-quote open-quote zig-zag close-quote close-quote path to fusion energy production. copyright 1996 American Institute of Physics

  19. A fractional-N frequency synthesizer for WCDMA/Bluetooth/ZigBee applications

    Science.gov (United States)

    Chunyuan, Zhou; Guolin, Li; Chun, Zhang; Baoyong, Chi; Dongmei, Li; Zhihua, Wang

    2009-07-01

    A triple-mode fractional-N frequency synthesizer with a noise-filter voltage controlled oscillator (VCO) for WCDMA/Bluetooth/ZigBee applications has been implemented in 0.18-μm RF-CMOS technology. The proposed synthesizer achieves a good phase noise lower than -80 dBc/Hz in band and -115 dBc/Hz@1 MHz for the three modes, and only draws 21 mA from a 1.8 V supply. It has a high hardware sharing and a small size, only 1.5 × 1.4 mm2. The system architecture, circuit design, and measured results are also presented.

  20. A fractional-N frequency synthesizer for WCDMA/Bluetooth/ZigBee applications

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Chunyuan; Zhang Chun; Chi Baoyongi; Wang Zhihua [Institute of Microelectronics, Tsinghua University, Beijing 100084 (China); Li Guolin; Li Dongmei, E-mail: zhoucy06@mails.tsinghua.edu.c [Department of Electronic Engineering, Tsinghua University, Beijing 100084 (China)

    2009-07-15

    A triple-mode fractional-N frequency synthesizer with a noise-filter voltage controlled oscillator (VCO) for WCDMA/Bluetooth/ZigBee applications has been implemented in 0.18-{mu}m RF-CMOS technology. The proposed synthesizer achieves a good phase noise lower than -80 dBc/Hz in band and -115 dBc/Hz-1 MHz for the three modes, and only draws 21 mA from a 1.8 V supply. It has a high hardware sharing and a small size, only 1.5 x 1.4 mm{sup 2}. The system architecture, circuit design, and measured results are also presented.

  1. One-particle versus two-particle crossover in weakly coupled Hubbard chains and ladders: perturbative renormalization group approach

    International Nuclear Information System (INIS)

    Kishine, Jun-Ichiro; Yonemitsu, Kenji

    1998-01-01

    Physical nature of dimensional crossovers in weakly coupled Hubbard chains and ladders has been discussed within the framework of the perturbative renormalization-group (PRG) approach. The difference between these two cases originates from different universality classes which the corresponding isolated systems belong to. In the present work, we discuss the nature of the dimensional crossovers in the weakly coupled chains and ladders, with emphasis on the difference between the two cases within the framework of the PRG approach. The difference of the universality class of the isolated chain and ladder profoundly affects the relevance or irrelevance of the inter-chain/ladder one-particle hopping. The strong coupling phase of the isolated ladder makes the one-particle process irrelevant so that the d-wave superconducting transition can be induced via the two-particle crossover in the weakly coupled ladders. The weak coupling phase of the isolated chain makes the one-particle process relevant so that the two-particle crossover can hardly be realized in the coupled chains. (Copyright (1998) World Scientific Publishing Co. Pte. Ltd)

  2. NMR study of spin dynamics in mesoscopic molecular clusters

    Science.gov (United States)

    Borsa, Ferdinando

    1998-03-01

    Recent published and umpublished work regarding the magnetic properties and the spin dynamics of molecules containing rings of 6,8 and 10 spins and of molecules containing clusters of 8 and 12 spins are reviewed. The 1H nuclear spin-lattice relaxation rate (NSLR) and the Muon Spin Resonance relaxation in Mn12 (A.Lascialfari, D.Gatteschi, F.Borsa, A.Shastri, Z.H.Jang and P.Carretta, Phys.Rev. B 1 January 1998) and Fe8 clusters are presented and discussed with regards to the high temperature spin dynamics of the Mn (Fe) magnetic moments and with regards to the low temperature superparamagnetic behavior. 1H and 63Cu NMR results are presented for two "quantum" spin rings : Cu6 and Cu8. The Cu6 is a weakly coupled (J/k=60K) ferromagnetic S=1/2 spin ring while Cu8 is a strongly coupled (J/k greater than 400K) antiferromagnetic S=1/2 spin ring.The dependence of the NSRL from temperature and from applied magnetic field are analyzed in terms of the calculated magnetic energy levels of the magnetic ring. The values of the energy gap between the ground state and the first excited state are extracted from the exponential decrease of the NSLR as the temperature is lowered. The results in the Cu ( S=1/2) "quantum" rings are compared with the results in "quantum" chains and ladders and with the results in "classical" Fe (S=5/2) antiferromagnetic rings : Fe6 and Fe10 (A.Lascialfari, D.Gatteschi, F.Borsa and A.Cornia , Phys.Rev. 55B,14341,1997) ).

  3. Construction and test of the first Belle II SVD ladder implementing the origami chip-on-sensor design

    International Nuclear Information System (INIS)

    Irmler, C.; Bauer, A.; Bergauer, T.; Adamczyk, K.; Bacher, S.; Aihara, H.; Angelini, C.; Batignani, G.; Bettarini, S.; Bosi, F.; Aziz, T.; Babu, V.; Bahinipati, S.; Barberio, E.; Baroncelli, Ti.; Baroncelli, To.; Basith, A.K.; Behera, P.K.; Bhuyan, B.; Bilka, T.

    2016-01-01

    The Belle II Silicon Vertex Detector comprises four layers of double-sided silicon strip detectors (DSSDs), consisting of ladders with two to five sensors each. All sensors are individually read out by APV25 chips with the Origami chip-on-sensor concept for the central DSSDs of the ladders. The chips sit on flexible circuits that are glued on the top of the sensors. This concept allows a low material budget and an efficient cooling of the chips by a single pipe per ladder. We present the construction of the first SVD ladders and results from precision measurements and electrical tests

  4. Fermion-boson scattering in ladder approximation

    International Nuclear Information System (INIS)

    Jafarov, R.G.; Hadjiev, S.A.

    1992-10-01

    A method of calculation of forward scattering amplitude for fermions and scalar bosons with exchanging of scalar particle is suggested. The Bethe-Salpeter ladder equation for the imaginary part of the amplitude is constructed and a solution in Regge asymptotical form is found and the corrections to the amplitude due to the exit from mass shell are calculated. (author). 8 refs

  5. The laddering method in service innovation research

    DEFF Research Database (Denmark)

    Grünbaum, Niels Nolsøe

    2017-01-01

    The laddering method is a qualitative interview technique applied in a situation with one interviewer and one informant with the aim of creating an understanding of the value that business-to-consumer (B2C) customers extract from product attributes. Thus, this methodology aims to depict a mental ...

  6. A robustification of the chain-ladder method

    NARCIS (Netherlands)

    Verdonck, T.; van Wouwe, M.; Dhaene, J.

    2009-01-01

    In a non-life insurance business an insurer often needs to build up a reserve to able to meet his or her future obligations arising from incurred but not reported completely claims. To forecast these claims reserves, a simple but generally accepted algorithm is the classical chain-ladder method.

  7. Utilization of the fish ladder at the Engenheiro Sergio Motta Dam, Brazil, by long distance migrating potamodromous species

    Directory of Open Access Journals (Sweden)

    Sérgio Makrakis

    Full Text Available Utilization of the fish ladder installed at the Engenheiro Sergio Motta Dam (also known as Porto Primavera on the Paraná River, Southern Brazil, by long-distance migrating potamodromous species (sampling Protocol I, and ascending and descending movements (Protocol II were evaluated. Three pools along the fish ladder (designated as lower, middle, and upper were sampled monthly between December, 2004 and March, 2005 to determine the abundance of species in the ladder. The ascending and descending movements of the species in the ladder were also analyzed in the same period. In the samples for both protocols, 37 species representing 17 families and 5 orders (Characiformes, Siluriformes, Perciformes, Gymnotiformes, and Myliobatiformes were recorded. Characiformes were represented by 21 species. Long- distance migratory species (11 species predominated in the ladder (60% of the total number of individuals, with high abundance of Rhinelepis aspera (5645 individuals. For protocol I, mean abundance varied greatly among the months and pools, with lowest values in December and March for all pools, and highest in January for the lower pool due to high capture of R. aspera. Fish abundance declined from the lower to the upper pool, especially for R. aspera and Rhaphiodon vulpinus. For Protocol II, 17 species were recorded ascending the ladder, where Astyanax altiparanae and Leporinus friderici were the most abundant species (684 and 111 individuals, respectively. However, 18 species showed descending movements, with high captures of Metynnis maculatus and A. altiparanae (339 and 319 individuals, respectively. Twelve species (52% moved in both directions, and among the seven migratory species sampled, four were recorded ascending and descending, and three species only ascending the ladder. The fish ladder appears to selectively favor species with high swimming capabilities. A discussion is presented on the requirements for future research on attraction to the

  8. Adaptation of a ladder beam walking task to assess locomotor recovery in mice following spinal cord injury

    Science.gov (United States)

    Cummings, Brian J.; Engesser-Cesar, Christie; Anderson, Aileen J.

    2007-01-01

    Locomotor impairments after spinal cord injury (SCI) are often assessed using open-field rating scales. These tasks have the advantage of spanning the range from complete paralysis to normal walking; however, they lack sensitivity at specific levels of recovery. Additionally, most supplemental assessments were developed in rats, not mice. For example, the horizontal ladder beam has been used to measure recovery in the rat after SCI. This parametric task results in a videotaped archival record of the event, is easily administered, and is unambiguously scored. Although a ladder beam apparatus for mice is available, its use in the assessment of recovery in SCI mice is rare, possibly because normative data for uninjured mice and the type of step misplacements injured mice exhibit is lacking. We report the development of a modified ladder beam instrument and scoring system to measure hindlimb recovery in vertebral T9 contusion spinal cord injured mice. The mouse ladder beam allows for the use of standard parametric statistical tests to assess locomotor recovery. Ladder beam performance is consistent across four strains of mice, there are no sex differences, and inter-rater reliability between observers is high. The ladder beam score is proportional to injury severity and can be used to easily separate mice capable of weight-supported stance up to mice with consistent forelimb to hindlimb coordination. Critically, horizontal ladder beam testing discriminates between mice that score identically in terms of stepping frequency in open-field testing. PMID:17197044

  9. Adaptation of a ladder beam walking task to assess locomotor recovery in mice following spinal cord injury.

    Science.gov (United States)

    Cummings, Brian J; Engesser-Cesar, Christie; Cadena, Gilbert; Anderson, Aileen J

    2007-02-27

    Locomotor impairments after spinal cord injury (SCI) are often assessed using open-field rating scales. These tasks have the advantage of spanning the range from complete paralysis to normal walking; however, they lack sensitivity at specific levels of recovery. Additionally, most supplemental assessments were developed in rats, not mice. For example, the horizontal ladder beam has been used to measure recovery in the rat after SCI. This parametric task results in a videotaped archival record of the event, is easily administered, and is unambiguously scored. Although a ladder beam apparatus for mice is available, its use in the assessment of recovery in SCI mice is rare, possibly because normative data for uninjured mice and the type of step misplacements injured mice exhibit is lacking. We report the development of a modified ladder beam instrument and scoring system to measure hindlimb recovery in vertebral T9 contusion spinal cord injured mice. The mouse ladder beam allows for the use of standard parametric statistical tests to assess locomotor recovery. Ladder beam performance is consistent across four strains of mice, there are no sex differences, and inter-rater reliability between observers is high. The ladder beam score is proportional to injury severity and can be used to easily separate mice capable of weight-supported stance up to mice with consistent forelimb to hindlimb coordination. Critically, horizontal ladder beam testing discriminates between mice that score identically in terms of stepping frequency in open-field testing.

  10. Fish ladder of Lajeado Dam: migrations on one-way routes?

    Directory of Open Access Journals (Sweden)

    Angelo Antônio Agostinho

    Full Text Available Fish ladders are generally conceived to reestablish connectivity among critical habitats for migratory species, thus mitigating the impacts of the blockage of migration routes by dams. If this management tool is to be meaningful for conserving fish species, it must provide a fully permeable connection and assure both upward and downward movements. However, because reservoirs have very different hydrodynamics than the original river, it is expected that, at least in the inner area, they may constitute an additional barrier to this movement, especially for descending fish. Thus, the present study sought to determine if migratory fish and their offspring disperse downstream from the dam after ascending a ladder and spawning in the upper reaches of a basin. To achieve this purpose, we evaluated the limitation imposed by lentic areas to the descent of eggs, larvae and adults of migratory species; we also determined the abundance and composition of larvae present in the plankton near the dam, and compared the intensity of the upward and downward movements of adult fish. Samples of ichthyoplankton were taken upriver, inside the reservoir, in the river downstream from the dam, and in the forebay of the Lajeado Dam on the Tocantins River (Luis Eduardo Magalhães Hydroelectric Plant, from October, 1999 through September, 2004. The densities of fish ascending and descending the ladder were determined experimentally on eight occasions, from June, 2004 to March, 2005. Due to difficulties in identifying the true fish origin (up or down in the environments connected by the fish passage system, the evaluation of the distribution of migratory fish in reservoirs was based on the landings of the commercial fishery conducted along the Itaipu Reservoir during the four years preceding (2001 through 2003 the construction of the lateral channel (fish-passage mechanism. Fish eggs and larvae drifting down the Tocantins River did not appear in samples taken in the lower

  11. Solvent induced synthesis, structure and properties of coordination polymers based on 5-hydroxyisophthalic acid as linker and 1,10-phenanthroline as auxiliary ligand

    Energy Technology Data Exchange (ETDEWEB)

    Kariem, Mukaddus; Yawer, Mohd; Sheikh, Haq Nawaz, E-mail: hnsheikh@rediffmail.com

    2015-11-15

    Three new coordination polymers [Mn(hip)(phen) (H{sub 2}O)]{sub n} (1), [Co(hip)(phen) (H{sub 2}O)]{sub n} (2), and [Cd(hip) (phen) (H{sub 2}O)]{sub n} (3) (H{sub 2}hip=5-hydroxyisophthalic acid; phen=1,10-phenanthroline) have been synthesized by solvo-hydrothermal method using diethyl formamide-water (DEF-H{sub 2}O) as solvent system. Single-crystal X-ray diffraction analysis reveals that all three coordination polymers 1, 2 and 3 crystallize in monoclinic space group P2/n. Metal ions are inter-connected by hydroxyisophthalate anions forming zig-zag 1D chain. 1D chains are further inter-connected by hydrogen bonding and π–π stacking interactions leading to 3D supramolecular architecture. Hydrogen-bonding and π–π stacking provide thermal stability to polymers. Compounds 1 and 2 are paramagnetic at room temperature and variable temperature magnetic moment measurements revealed weak ferromagnetic interactions between metal ions at low temperature. Compound 3 exhibits excellent photoluminescence with large Stokes shift. - Graphical abstract: 1D helical chains of coordination polymers were synthesized by solvo-hydrothermal reaction of 5-hydroxyisopthalic acid and 1,10-phenanthroline with MnCl{sub 2}·4H{sub 2}O / CoCl{sub 2}·6H{sub 2}O / Cd(NO{sub 3}){sub 2}·6H{sub 2}O. - Highlights: • Solvent induced synthesis of three coordination polymers with 1D zig-zag structure. • Crystal structures of coordination polymers are reported and discussed. • 1,10-Phenanthroline influences magnetic and luminescent properties of polymers. • Coordination polymer of Cd is luminescent exhibiting large Stokes shift.

  12. 49 CFR 214.519 - Floors, decks, stairs, and ladders of on-track roadway maintenance machines.

    Science.gov (United States)

    2010-10-01

    ... roadway maintenance machines. 214.519 Section 214.519 Transportation Other Regulations Relating to... SAFETY On-Track Roadway Maintenance Machines and Hi-Rail Vehicles § 214.519 Floors, decks, stairs, and ladders of on-track roadway maintenance machines. Floors, decks, stairs, and ladders of on-track roadway...

  13. Flapping, wobbling, and zig-zagging: Tomographic PIV measurements of Antarctic sea butterfly ``flying'' underwater

    Science.gov (United States)

    Adhikari, D.; Webster, D. R.; Yen, J.

    2015-11-01

    A portable tomographic PIV technique was used to study the fluid dynamics and kinematics of sea butterflies in Antarctica. Antarctic pteropods (or sea butterflies), which are currently threatened by ocean acidification, swim in seawater with a pair of gelatinous parapodia (or ``wings'') via a unique propulsion mechanism. Both power and recovery strokes propel the organism (1.5 - 5 mm in size) upward in a sawtooth-like trajectory with average speed of 14 - 30 mm/s and pitch the shell forwards-and-backwards at 1.9 - 3 Hz. The pitching motion effectively positions the parapodia such that they stroke downward during both the power and recovery strokes. Reynolds numbers defined for flapping, translating, and pitching (i.e. Ref, ReU, and ReΩ) characterize the motion of the pteropod. For Ref <50, the shell does not pitch and the pteropod swims abnormally. We present a detailed comparison of the volumetric fluid velocity fields induced by pteropods swimming upwards with Ref = 80 and 180. The pteropod at the lower Ref creates an attached shear flow along the parapodia and pushes fluid in a method analogous to a paddle. In contrast, at higher Ref, the flow along the parapodia separates and generates complex vortex structures.

  14. The Broken Zig-Zag: Late Cenozoic large mammal and tortoise extintion in South America

    OpenAIRE

    Tonni, Eduardo Pedro; Cione, Alberto Luis; Soibelzon, Leopoldo Héctor

    2003-01-01

    During the latest Pleistocene-earliest Holocene, South American terrestrial vertebrate faunas suffered one of the largest (and probably the youngest) extinction in the world for this lapse. Megamammals, most of the large mammals and a giant terrestrial tortoise became extinct in the continent, and several complete ecological guilds and their predators disappeared. This mammal extinction had been attributed mainly to overkill, climatic change or a combination of both. We agree with the idea th...

  15. The Design of Wireless Sensor Network System Based on ZigBee Technology for Greenhouse

    International Nuclear Information System (INIS)

    Zhu, Y W; Zhong, X X; Shi, J F

    2006-01-01

    Wireless sensor network is a new research field. It can be used in some special situation for signal collection, processing and transmitting. Zigbee is a new Wireless sensor network technology characteristic of less distance and low speed. It is a new wireless network protocol stack of IEEE 802.15.4. Lately traditional system to collects parameters for Greenhouse is widely used in agriculture. The traditional system adopts wired way wiring, which makes the system complex and expensive. Generally modern Greenhouse has hundreds of square meters and they may plant variety of plants depending on different seasons. So we need to adjust the sensors which collect parameters for Greenhouse to a better place to work more efficient. Adopting wireless way wiring is convenient and economical. This paper developed a wireless sensor network system based on ZigBee technology for greenhouse. It offers flexibility and mobility to save cost and energy spent on wiring. The framework hardware and software structure, related programming are also discussed in this paper. Comparing the system which uses ZigBee technology with traditional wired network system for greenhouse, it has advantage of low cost..low power and wider coverage. Additionally it complies with IEEE802.15.4 protocol, which makes it convenient to communicate with other products that comply with the protocol too

  16. Explaining choice option attractiveness by beliefs elicited by the laddering method

    DEFF Research Database (Denmark)

    Grunert, Klaus G.; Bech-Larsen, Tino

    2005-01-01

    option. The laddering method is used to elicit beliefs of all three types for a choice between conventional and organic pork. As a benchmark, beliefs were also elicited in the traditional way advocated by Ajzen and Fishbein. Using both sets of beliefs in a subsequent survey, it was shown that the beliefs...... elicited by the laddering method increase explanatory power with regard to choice option attractiveness beyond the beliefs elicited by the Ajzen and Fishbein method, and that this additional explanatory power was due to those beliefs which relate the choice option to concepts with a higher level...

  17. Phase diagram of a bosonic ladder with two coupled chains

    International Nuclear Information System (INIS)

    Luthra, Meetu Sethi; Mishra, Tapan; Pai, Ramesh V.; Das, B. P.

    2008-01-01

    We study a bosonic ladder with two coupled chains using the finite-size density-matrix renormalization group method. We show that in a commensurate bosonic ladder the critical on-site interaction (U C ) for the superfluid to Mott insulator transition gets larger as the interchain hopping (t perpendicular ) increases. We analyze this quantum phase transition and obtain the phase diagram in the t perpendicular -U plane. We also consider the asymmetric case where the on-site interactions are different in the two chains and have shown that the system as a whole will not be in the Mott insulator phase unless both the chains have on-site interactions greater than the critical value

  18. Effects of gravity level on bubble formation and rise in low-viscosity liquids

    Science.gov (United States)

    Suñol, Francesc; González-Cinca, Ricard

    2015-05-01

    We present an experimental analysis of the effects of gravity level on the formation and rise dynamics of bubbles. Experiments were carried out with millimeter-diameter bubbles in the hypergravity environment provided by the large-diameter centrifuge of the European Space Agency. Bubble detachment from a nozzle is determined by buoyancy and surface tension forces regardless of the gravity level. Immediately after detachment, bubble trajectory is deviated by the Coriolis force. Subsequent bubble rise is dominated by inertial forces and follows a zig-zag trajectory with amplitude and frequency dependent on the gravity level. Vorticity production is enhanced as gravity increases, which destabilizes the flow and therefore the bubble path.

  19. Endotracheal expandable metallic stent placement in dogs

    Energy Technology Data Exchange (ETDEWEB)

    Sawada, S; Tanabe, Y; Fujiwara, Y; Koyama, T; Tanigawa, N; Kobayashi, M; Katsube, Y; Nakamura, H [Tottori Univ. School of Medicine, Yonago (Japan). Dept. of Radiology Research Inst. for Microbial Diseases, Osaka (Japan). Dept. of Radiology

    1991-01-01

    Various types of Gianturco zig-zag wire stent were implanted into the tracheas of 4 dogs to define the suitable characteristics of the endotracheal wire stent in these animals. These stents were constructed of 0.45, and 0.33 mm stainless steel wire. The diameter of the fully expanded stents was 3 cm and their lengths were 2, 3, and 4 cm. The 2 cm stent constructed of 0.33 mm wire showed minimum pathologic changes of the trachea of the dog compared to the other stents, and at the same time had a complete covering of ciliated columnar epithelium over the stent surface. (orig.).

  20. Apparatus for controlling molten core debris

    International Nuclear Information System (INIS)

    Golden, M.P.; Tilbrook, R.W.; Heylmun, N.F.

    1972-01-01

    Disclosed is an apparatus for containing, cooling, diluting, dispersing and maintaining subcritical the molten core debris assumed to melt through the bottom of a nuclear reactor pressure vessel in the unlikely event of a core meltdown. The apparatus is basically a sacrificial bed system which includes an inverted conical funnel, a core debris receptacle including a spherical dome, a spherically layered bed of primarily magnesia bricks, a cooling system of zig-zag piping in graphite blocks about and below the bed and a cylindrical liner surrounding the graphite blocks including a steel shell surrounded by firebrick. Tantalum absorber rods are used in the receptacle and bed. 9 claims, 22 figures

  1. Geological-structural interpretation using products of remote sensing in the region of Carrancas, Minas Gerais, Brazil

    Science.gov (United States)

    Parada, N. D. J. (Principal Investigator); Dossantos, A. R.; Dosanjos, C. E.; Barbosa, M. P.; Veneziani, P.

    1982-01-01

    The efficiency of some criteria developed for the utilization of small scale and low resolution remote sensing products to map geological and structural features was demonstrated. Those criteria were adapted from the Logical Method of Photointerpretation which consists of textural qualitative analysis of landforms and drainage net patterns. LANDSAT images of channel 5 and 7, 4 LANDSAT-RBV scenes, and 1 radar mosiac were utilized. The region of study is characterized by supracrustal metassediments (quartzites and micaschist) folded according to a "zig-zag" pattern and gnaissic basement. Lithological-structural definition was considered outstanding when compared to data acquired during field work, bibliographic data and geologic maps acquired in larger scales.

  2. Virtual maneuvering test in CFD media in presence of free surface

    Directory of Open Access Journals (Sweden)

    Ahmad Hajivand

    2015-05-01

    Full Text Available Maneuvering oblique towing test is simulated in a Computational Fluid Dynamic (CFD environment to obtain the linear and nonlinear velocity dependent damping coefficients for a DTMB 5512 model ship. The simulations are carried out in freely accessible OpenFOAM library with three different solvers, rasInterFoam, LTSInterFoam and interDyMFoam, and two turbulence models, k-ε and SST k-ω in presence of free surface. Turning and zig-zag maneuvers are simulated for the DTMB 5512 model ship using the calculated damping coefficients with CFD. The comparison of simulated results with the available experimental shows a very good agreement among them.

  3. Interlayer Structure of Bioactive Molecule, 2-Aminoethanesulfonate, Intercalated into Calcium-Containing Layered Double Hydroxides

    Directory of Open Access Journals (Sweden)

    Tae-Hyun Kim

    2012-01-01

    Full Text Available We have successfully intercalated 2-aminoethanesulfonate, a well-known biomolecule taurine, into calcium-containing layered double hydroxides via optimized solid phase intercalation. According to X-ray diffraction patterns and infrared spectroscopy, it was revealed that the intercalated taurine molecules were each directly coordinated to other calcium cation and arranged in a zig-zag pattern. Scanning electron microscopy showed that the particle size and morphology of the LDHs were not affected by the solid phase intercalation, and the surface of intercalates was covered by organic moieties. From ninhydrin amine detection tests, we confirmed that most of the taurine molecules were well stabilized between the calcium-containing LDH layers.

  4. Action–angle variables, ladder operators and coherent states

    International Nuclear Information System (INIS)

    Campoamor-Stursberg, R.; Gadella, M.; Kuru, Ş.; Negro, J.

    2012-01-01

    This Letter is devoted to the building of coherent states from arguments based on classical action–angle variables. First, we show how these classical variables are associated to an algebraic structure in terms of Poisson brackets. In the quantum context these considerations are implemented by ladder type operators and a structure known as spectrum generating algebra. All this allows to generate coherent states and thereby the correspondence of classical–quantum properties by means of the aforementioned underlying structure. This approach is illustrated with the example of the one-dimensional Pöschl–Teller potential system. -- Highlights: ► We study the building of coherent states from classical action–angle variables arguments. ► The classical variables are associated to an algebraic structure in terms of Poisson brackets. ► In the quantum context these considerations are implemented by ladder type operators. ► All this allows to formulate coherent states and the correspondence of classical–quantum properties.

  5. Resonance self-shielding calculation with regularized random ladders

    Energy Technology Data Exchange (ETDEWEB)

    Ribon, P.

    1986-01-01

    The straightforward method for calculation of resonance self-shielding is to generate one or several resonance ladders, and to process them as resolved resonances. The main drawback of Monte Carlo methods used to generate the ladders, is the difficulty of reducing the dispersion of data and results. Several methods are examined, and it is shown how one (a regularized sampling method) improves the accuracy. Analytical methods to compute the effective cross-section have recently appeared: they are basically exempt from dispersion, but are inevitably approximate. The accuracy of the most sophisticated one is checked. There is a neutron energy range which is improperly considered as statistical. An examination is presented of what happens when it is treated as statistical, and how it is possible to improve the accuracy of calculations in this range. To illustrate the results calculations have been performed in a simple case: nucleus /sup 238/U, at 300 K, between 4250 and 4750 eV.

  6. "Ladder" structure in tonal noise generated by laminar flow around an airfoil.

    Science.gov (United States)

    Chong, Tze Pei; Joseph, Phillip

    2012-06-01

    The presence of a "ladder" structure in the airfoil tonal noise was discovered in the 1970s, but its mechanism hitherto remains a subject of continual investigation in the research community. Based on the measured noise results and some numerical analysis presented in this letter, the variations of four types of airfoil tonal noise frequencies with the flow velocity were analyzed individually. The ladder structure is proposed to be caused by the acoustic/hydrodynamic frequency lag between the scattering of the boundary layer instability noise and the discrete noise produced by an aeroacoustic feedback loop.

  7. High-energy, large-momentum-transfer processes: Ladder diagrams in var-phi 3 theory

    International Nuclear Information System (INIS)

    Newton, C.L.J.

    1990-01-01

    Relativistic quantum field theories may help one to understand high-energy, large-momentum-transfer processes, where the center-of-mass energy is much larger than the transverse momentum transfers, which are in turn much larger than the masses of the participating particles. With this possibility in mind, the author studies ladder diagrams in var-phi 3 theory. He shows that in the limit s much-gt |t| much-gt m 2 , the scattering amplitude for the N-rung ladder diagram takes the form s -1 |t| -N+1 times a homogeneous polynomial of degree 2N - 2 and ln s and ln |t|. This polynomial takes different forms depending on the relation of ln |t| to ln s. More precisely, the asymptotic formula for the N-rung ladder diagram has points of non-analytically when ln |t| = γ ln s for γ = 1/2, 1/3, hor-ellipsis, 1/N-2

  8. Hopping ladder and power relaxation due to donor-acceptor pairs

    International Nuclear Information System (INIS)

    Kostadinov, I.Z.

    1985-11-01

    Hopping between donor-acceptor pairs leads to peculiar temperature dependence of the conductivity and the photoconductivity under subband gap illumination in the form of non-linear activation energies ladder. The correlated and uncorrelated distributions of pairs are considered and the conditions for the ladder existence are determined. The relaxation of the carrier concentration fluctuations is studied and power type decay is found. The temperature dependence of the exponent is calculated in agreement with the non-exponential decay of the pulse excited luminescence observed by Dean et al. The temperature dependence of the luminescence intensity also shows variable activation energy as found here. The exponent value α=1.316 is also in agreement with the data for crystalline and amorphous materials. (author)

  9. A D- and N-15-Rich Micrometer-Sized Aggregate of Organic Matter in a Xenolithic Clast from the Zag Ordinary Chondrite

    Science.gov (United States)

    Kebukawa, Yoko; Ito, Motoo; Zolensky, Michael E.; Rahman, Zia; Suga, Hiroki; Nakato, Aiko; Chan, Queenie H. S.; Fries, Marc; Takeichi, Yasuo; Takahashi, Yoshio; hide

    2018-01-01

    The nature and origin of extraterrestrial organic matter are still under debate despite the significant progress in the analyses and experimental approaches in this field over the last five decades. Xenolithic clasts are often found in a wide variety of meteorite groups, some of which contain exotic organic matter (OM). The Zag meteorite is a thermally-metamorphosed H ordinary chondrite. It contains a primitive xenolithic clast that has been proposed to have originated from Ceres, which was accreted to the Zag host asteroid after metamorphism. The cm-sized clast contains abundant large carbon-rich (mostly organic) grains or aggregates up to 20 microns. Such large OM grains are unique among astromaterials with respect to the size. Here we report organic and isotope analyses of a large (approx.10 microns) aggregate of solid OM in the Zag clast. The X-ray micro-spectroscopic technique revealed that the OM has sp2 bonded carbon with no other functional groups nor graphitic feature (1s-sigma exciton), and thus it is distinguished from most of the OM in carbonaceous meteorites. The apparent absence of functional groups in the OM suggests that it is composed of hydrocarbon networks with less heteroatoms, and therefore the OM aggregate is similar to hydrogenated amorphous carbon (HAC). The OM aggregate has high D/H and 15N/14N ratios, suggesting that it originated in a very cold environment such as the interstellar medium or outer region of the solar nebula, while the OM is embedded in carbonate-bearing matrix resulting from aqueous activities. Thus the high D/H ratio must have survived the extensive late-stage aqueous processing. It is not in the case for OM in carbonaceous chondrites of which the D/H ratio was reduced by the alteration via the D-H exchange of water. It indicates that both the OM precursors and the water had high D/H ratios, similar to the water in Enceladus. Our results support the idea that the clast originated from Ceres, or at least, a

  10. Nuclear spin relaxation in a spin-1/2 antiferromagnetic Heisenberg chain at high fields

    International Nuclear Information System (INIS)

    Lyo, S.K.

    1981-01-01

    The proton spin relaxation rate is calculated in the one-dimensional spin-1/2 Heisenberg antiferromagnet α-bis (N-methylsalicylaldiminato)-copper (II), α-CuNSal by using a fermion representation for magnons above the critical field where the magnon spectrum develops a gap. The one-magnon process which is dominant below the critical field is shown to be absent in the presence of a gap in contrast to a previous theory. Instead, we find that the three-magnon rate is large enough to explain the data at low fields. The two-magnon off-resonance damping which enters the expression for the three-magnon rate is calculated by solving the two-magnon scattering exactly, leading to a much smaller value of the rate than that predicted by the Born approximation. Also, in an unsuccessful attempt to resolve the discrepancy between the recently calculated two-magnon rate (dominant at high fields) and the data of α-CuNSal reported by Azevedo et al., we carry out the vertex correction for the spin-density correlation function by summing the RPA series as well as the exchange ladders for the polarization part. We find that, although the exchange enhancement is significantly large, it is nearly canceled out by the RPA correction, and the net effect of the vertex correction is small. This result agrees with the recent data of the similar spin-1/2 antiferromagnetic Heisenberg chain system CuSO 4 x5H 2 O reported by Groen et al. On the other hand, it disagrees with a recent calculation of the two-magnon rate based on a boson representation of spins. To resolve this discrepancy we examine the effect of the boson self-energy correction on the two-magnon rate. The boson spectral shift is found to be quite large in the region where the cited two-boson rate deviates from the two-fermion rate. As a result the two-boson rate is significantly reduced, leading to reasonable agreement with the two-fermion rate

  11. Model Comparison Exercise Circuit Training Game and Circuit Ladder Drills to Improve Agility and Speed

    Directory of Open Access Journals (Sweden)

    Susilaturochman Hendrawan Koestanto

    2017-11-01

    Full Text Available The purpose of this study was to compare: (1 the effect of circuit training game and circuit ladder drill for the agility; (2 the effect of circuit training game and circuit ladder drill on speed; (3 the difference effect of circuit training game and circuit ladder drill for the speed (4 the difference effect of circuit training game and circuit ladder drill on agility. The type of this research was quantitative with quasi-experimental methods. The design of this research was Factorial Design, with analysing data using ANOVA. The process of data collection was done by using 30 meters sprint speed test and shuttle run test during the pretest and posttest. Furthermore, the data was analyzed by using SPSS 22.0 series. Result: The circuit training game exercise program and circuit ladder drill were significant to increase agility and speed (sig 0.000 < α = 0.005 Group I, II, III had significant differences (sig 0.000 < α = 0.005. The mean of increase in speed of group I = 0.20 seconds, group II = 0.31 seconds, and group III = 0.11 seconds. The average increase agility to group I = 0.34 seconds group II = 0.60 seconds, group III = 0.13 seconds. Based on the analysis above, it could be concluded that there was an increase in the speed and agility of each group after being given a training.

  12. Research on Environmental real-time γ-radiation monitoring systems based on ZigBee

    International Nuclear Information System (INIS)

    Chen Wei; Cui Yan; Fang Fang; Zhou Wei

    2008-01-01

    The system makes use of ZigBee wireless network technology to realize the continuous monitoring the the environmental γ radiation around the nuclear power plant with the most economic cost and the most reliable performance. In order to improve the reliability of data transmission, the system is made up of three tiered network architecture which is composed of center-node, monitoring relay station and monitoring substation. This paper introduces the establish of each network in monitoring network, the design of each terminal monitoring node and the implementation method of host computer data processing system in detail. (authors)

  13. Healthcare organization-education partnerships and career ladder programs for health care workers.

    Science.gov (United States)

    Dill, Janette S; Chuang, Emmeline; Morgan, Jennifer C

    2014-12-01

    Increasing concerns about quality of care and workforce shortages have motivated health care organizations and educational institutions to partner to create career ladders for frontline health care workers. Career ladders reward workers for gains in skills and knowledge and may reduce the costs associated with turnover, improve patient care, and/or address projected shortages of certain nursing and allied health professions. This study examines partnerships between health care and educational organizations in the United States during the design and implementation of career ladder training programs for low-skill workers in health care settings, referred to as frontline health care workers. Mixed methods data from 291 frontline health care workers and 347 key informants (e.g., administrators, instructors, managers) collected between 2007 and 2010 were analyzed using both regression and fuzzy-set qualitative comparative analysis (QCA). Results suggest that different combinations of partner characteristics, including having an education leader, employer leader, frontline management support, partnership history, community need, and educational policies, were necessary for high worker career self-efficacy and program satisfaction. Whether a worker received a wage increase, however, was primarily dependent on leadership within the health care organization, including having an employer leader and employer implementation policies. Findings suggest that strong partnerships between health care and educational organizations can contribute to the successful implementation of career ladder programs, but workers' ability to earn monetary rewards for program participation depends on the strength of leadership support within the health care organization. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Phase diagram and re-entrant fermionic entanglement in a hybrid Ising-Hubbard ladder

    Science.gov (United States)

    Sousa, H. S.; Pereira, M. S. S.; de Oliveira, I. N.; Strečka, J.; Lyra, M. L.

    2018-05-01

    The degree of fermionic entanglement is examined in an exactly solvable Ising-Hubbard ladder, which involves interacting electrons on the ladder's rungs described by Hubbard dimers at half-filling on each rung, accounting for intrarung hopping and Coulomb terms. The coupling between neighboring Hubbard dimers is assumed to have an Ising-like nature. The ground-state phase diagram consists of four distinct regions corresponding to the saturated paramagnetic, the classical antiferromagnetic, the quantum antiferromagnetic, and the mixed classical-quantum phase. We have exactly computed the fermionic concurrence, which measures the degree of quantum entanglement between the pair of electrons on the ladder rungs. The effects of the hopping amplitude, the Coulomb term, temperature, and magnetic fields on the fermionic entanglement are explored in detail. It is shown that the fermionic concurrence displays a re-entrant behavior when quantum entanglement is being generated at moderate temperatures above the classical saturated paramagnetic ground state.

  15. Nestling diets and provisioning rates of sympatric Golden-fronted and Ladder-backed Woodpeckers

    Science.gov (United States)

    Schroeder, Evonne L.; Boal, Clint W.; Glasscock, Selma N.

    2013-01-01

    We examined comparative food use and provisioning of Golden-fronted (Melanerpes aurifrons) and Ladder-backed (Picoides scalaris) woodpeckers at the Rob and Bessie Welder Wildlife Foundation Refuge, in San Patricio County, Texas. We combined video surveillance and direct observations to monitor provisioning rates and identify items delivered by adult woodpeckers to nestlings. We collected 328 hours of data at Ladder-backed Woodpecker nest cavities and 230 hours of data at Golden-fronted Woodpecker nest cavities. Ladder-backed Woodpecker nestling diets consisted of 100% animal matter, comprised of invertebrate larvae (99%) and invertebrate adults (nestlings were also high in animal matter (77%) with more invertebrate adults (55%) and fewer invertebrate larvae (27%), but also included vegetable matter (16%). Morisita's measure of overlap suggested a relatively low dietary overlap of 31% between nestlings of these two sympatric woodpecker species. Foraging methods used by these species may explain their low dietary overlap and facilitate their coexistence.

  16. THE COMPARISON OF USING SNAKE LADDERS AND SCRABBLE MEDIA TOWARDS VOCABULARY MASTERY OF STUDENTS

    Directory of Open Access Journals (Sweden)

    Eka Pra Setiawati

    2017-02-01

    Full Text Available Vocabulary is an essential component in learning English. It influences four English skills; they are listening, speaking, reading, and writing, for getting a good result in English. In teaching learning process, the teacher often implements the less interesting method, technique, or even media of vocabulary mastery in teaching and learning process which make the students to be bored, inactive, an uniterested in memorizing English vocabulary. Some media can be interested as the solutions in vocabulary mastery, they are Snake Ladders media and Scrabble media. The investigation was undergone by quantitative research. The researcher applied experimental research. This research underwent pre-test post-test control group design. To analyze data, t-test formula is used to measure the result of collected data. From the t-test measurement, it showed that t-test is 3.15 and t-table is 2.66. It means that t-hit > t-table. Based on the collected data, there is different result of using Snake Ladders from Scrabble media toward students’ vocabulary mastery. It was found that the students who are taught by using Snake Ladders resulted significant outcome than those are instructed by Scrabble media. It means that Snake Ladders is effective to improve the students’ vocabulary mastery.

  17. Means-end chains and laddering: An inventory of problems and an agenda for research

    DEFF Research Database (Denmark)

    Grunert, Klaus G.; Grunert, Suzanne C.; Sørensen, Elin

    Executive summary 1. Means-end chains are a device used to understand how consumers mentally link products to self-relevant consequences. Means-end chains are usually measured by a method called laddering. 2. Means-end chains may fall short of tapping all relevant aspects of how consumers think...... about products. Specifically, nonverbal imagery, episodic information, and procedural knowledge are not included in means-end chains. 3. A number of methodological problems can be identified in the collection of means-end chain data. Major problems, which should be addressed in research, are methods...... to elicit the product attributes the laddering is to start with, the integration of a usage situation in the interview, and the basic decision on how much direct the respondent. 4. Concerning the coding of laddering data, a higher degree of transparency of the coding process would be desirable. 5...

  18. Means-end chains and laddering: An inventory of problems and an agenda for research

    DEFF Research Database (Denmark)

    Grunert, Klaus G.; Beckmann, Suzanne C.; Sørensen, Elin

    2001-01-01

    and unconscious (or, at least, semiconscious) factors. It is intuitively appealing to the practitioner but has, likewise, attracted academic research. Increased acceptance and use of a new approach inevitably leads to the detection of unresolved issues and problems. Many of these unresolved issues are related...... to the collection and analysis of laddering data. However, many of these also point at problems of a more theoretical nature. In this chapter presented are some of the issues regarded as unresolved and suggested research that could help in solving these problems. The mayor part of this chapter deals...... with methodological problems of the interview technique called laddering, og coding laddering data, and of analysing the coded data. However, also shown, methodological and theoretical issues are partly interlinked: resolutions of methodological problems may require theoretical progress or at least a clarification...

  19. In-line digital holography with phase-shifting Greek-ladder sieves

    Science.gov (United States)

    Xie, Jing; Zhang, Junyong; Zhang, Yanli; Zhou, Shenlei; Zhu, Jianqiang

    2018-04-01

    Phase shifting is the key technique in in-line digital holography, but traditional phase shifters have their own limitations in short wavelength regions. Here, phase-shifting Greek-ladder sieves with amplitude-only modulation are introduced into in-line digital holography, which are essentially a kind of diffraction lens with three-dimensional array diffraction-limited foci. In the in-line digital holographic experiment, we design two kinds of sieves by lithography and verify the validity of their phase-shifting function by measuring a 1951 U.S. Air Force resolution test target and three-dimensional array foci. With advantages of high resolving power, low cost, and no limitations at shorter wavelengths, phase-shifting Greek-ladder sieves have great potential in X-ray holography or biochemical microscopy for the next generation of synchrotron light sources.

  20. The snakes and ladders of National Health Service management in England.

    Science.gov (United States)

    Powell, Martin

    2014-01-01

    This article explores managerial careers in the National Health Service (NHS) through the lens of talent management, particularly focusing on how managers view barriers (snakes) and facilitators (ladders) to career progression. There is a significant literature on enablers and barriers to career progression, but much of this focuses on specific groups such as black and minority ethnic and female workers, and there is relatively little material on the general workforce of the NHS. The research design is a mixed method quantitative (questionnaire) and qualitative (interview and focus group) approach consisting of a quasi-probability element that focuses on a maximum variety sample and a purposive element that seeks policy views at central and strategic health authority level, and examines talent management in high-performing NHS organisations. Ladders are identified as follows: volunteering, secondment, networking, mentoring, academic qualifications, development, good role models/managers and appraisal/personal development plan. Snakes are identified as managing expectations; identity and cognitive diversity; location; sector; NHS toxic and favouritism culture; poor talent spotting; credentialism; exclusive approach to talent; and sustainability. It concludes that while previous conceptual and empirical work is fairly clear on any ladders, it is less clear on snakes. Copyright © 2013 John Wiley & Sons, Ltd.

  1. Structure of the conversion laws in quantum integrable spin chains with short range interactions

    International Nuclear Information System (INIS)

    Grabowski, M.P.; Mathieu, P.

    1995-01-01

    The authors present a detailed analysis of the structure of the conservation laws in quantum integrable chains of the XYZ-type and in the Hubbard model. The essential tool for the former class of models is the boost operator, which provides a recursive way of calculating the integrals of motion. With its help, they establish the general form of the XYZ conserved charges in terms of simple polynomials in spin variables and derive recursion relations for the relative coefficients of these polynomials. Although these relations are difficult to solve in general, a subset of the coefficients can be determined. Moreover, for two submodels of the XYZ chain, namely the XXX and XY cases, all the charges can be calculated in closed form. Using this approach, the authors rederive the known expressions for the XY charges in a novel way. For the XXX case. a simple description of conserved charges is found in terms of a Catalan tree. This construction is generalized for the su(M) invariant integrable chain. They also investigate the circumstances permitting the existence of a recursive (ladder) operator in general quantum integrable systems. They indicate that a quantum ladder operator can be traced back to the presence of a Hamiltonian mastersymmetry of degree one in the classical continuous version of the model. In this way, quantum chains endowed with a recursive structure can be identified from the properties of their classical relatives. The authors also show that in the quantum continuous limits of the XYZ model, the ladder property of the boost operator disappears. For the Hubbard model they demonstrate the nonexistence of a ladder operator. Nevertheless, the general structure of the conserved charges is indicated, and the expression for the terms linear in the model's free parameter for all charges is derived in closed form. 62 refs., 4 figs

  2. Air-Sense: indoor environment monitoring evaluation system based on ZigBee network

    Science.gov (United States)

    Huang, Yang; Hu, Liang; Yang, Disheng; Liu, Hengchang

    2017-08-01

    In the modern life, people spend most of their time indoors. However, indoor environmental quality problems have always been affecting people’s social activities. In general, indoor environmental quality is also related to our indoor activities. Since most of the organic irritants and volatile gases are colorless, odorless and too tiny to be seen, because we have been unconsciously overlooked indoor environment quality. Consequently, our body suffer a great health problem. In this work, we propose Air-Sense system which utilizes the platform of ZigBee Network to collect and detect the real-time indoor environment quality. What’s more, Air-Sense system can also provide data analysis, and visualizing the results of the indoor environment to the user.

  3. Ising-like spin anisotropy and competing antiferromagnetic-ferromagnetic orders in GdBaCo2O5.5 single crystals.

    Science.gov (United States)

    Taskin, A A; Lavrov, A N; Ando, Yoichi

    2003-06-06

    In RBaCo2O5+x compounds (R is rare earth), a ferromagnetic-antiferromagnetic competition is accompanied by a giant magnetoresistance. We study the magnetization of detwinned GdBaCo2O5.5 single crystals and find a remarkable uniaxial anisotropy of Co3+ spins which is tightly linked with the chain oxygen ordering in GdO0.5 planes. Reflecting the underlying oxygen order, CoO2 planes also develop a spin-state order consisting of Co3+ ions in alternating rows of S=1 and S=0 states. The magnetic structure appears to be composed of weakly coupled ferromagnetic ladders with Ising-like moments, which gives a simple picture for magnetotransport phenomena.

  4. High-Performance and Simply-Synthesized Ladder-Like Structured Methacrylate Siloxane Hybrid Material for Flexible Hard Coating

    Directory of Open Access Journals (Sweden)

    Yun Hyeok Kim

    2018-04-01

    Full Text Available A high performance ladder-like structured methacrylate siloxane hybrid material (LMSH was fabricated via simple hydrolytic sol–gel reaction, followed by free-radical polymerization. A structurally ordered siloxane backbone, the ladder-like structure, which is an essential factor for high performance, could be achieved by a short period of sol–gel reaction in only 4 h. This results in superior optical (Transmittance > 90% at 550 nm, thermal (T5 wt % decomposition > 400 ℃ , mechanical properties(elastic recovery = 0.86, hardness = 0.6 GPa compared to the random- and even commercialized cage-structured silsesquioxane, which also has ordered structure. It was investigated that the fabricated ladder-like structured MSH showed the highest overall density of organic/inorganic co-networks that are originated from highly ordered siloxane network, along with high conversion rate of polymerizable methacrylate groups. Our findings suggest a potential of the ladder-like structured MSH as a powerful alternative for the methacrylate polysilsesquioxane, which can be applied to thermally stable and flexible optical coatings, even with an easier and simpler preparation process.

  5. Chemodiversity of Ladder-Frame Prymnesin Polyethers in Prymnesium parvum

    DEFF Research Database (Denmark)

    Rasmussen, Silas Anselm; Meier, Sebastian; Andersen, Nikolaj Gedsted

    2016-01-01

    Blooms of the microalga Prymnesium parvum cause devastating fish kills worldwide, which are suspected to be caused by the supersized ladder-frame polyether toxins prymnesin-1 and -2. These toxins have, however, only been detected from P. parvum in rare cases since they were originally described two...

  6. Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE): Emissions of particulate matter from garbage burning, wood and dung cooking fires, motorcycles and brick kilns

    Science.gov (United States)

    Jayarathne, T. S.; Rathnayake, C.; Stockwell, C.; Daugherty, K.; Islam, R. M.; Christian, T. J.; Bhave, P.; Praveen, P. S.; Panday, A. K.; Adhikari, S.; Rasmi, M.; Goetz, D.; DeCarlo, P. F.; Saikawa, E.; Yokelson, R. J.; Stone, E. A.

    2016-12-01

    The Nepal Ambient Monitoring and Source Testing Experiment (NAMASTE) field campaign targeted the in-situ characterization of widespread and under-sampled combustion sources in South Asia by determining emission factors (EF) for fine particulate matter (PM2.5), organic carbon (OC), elemental carbon, inorganic ions, trace metals, and organic species. Garbage burning had the highest EF PM2.5 among the sampled sources ranging 7-124 g kg-1, with maximum EFs for garbage burned under higher moisture conditions. Garbage burning emissions contained high concentrations of polycyclic aromatic compounds (PAHs) and heavy metals (Pb, Cd, Zn) that are associated with acute and chronic health effects. Triphenylbenzene and antimony (Sb) were unique to garbage burning are good candidates for tracing this source. Cook stove emissions varied largely by stove technology (traditional mud stove, 3-stone cooking fire, chimney stove, etc.) and biomass fuel (dung, hardwood, twigs, and mixtures thereof). Burning dung consistently emitted more PM2.5 than burning wood and contained characteristic fecal sterols and stanols. Motorcycle emissions were evaluated before and after servicing, which decreased EF PM2.5 from 8.8 g kg-1 to 0.7 g kg-1. Organic species analysis indicated that this reduction in PM2.5­ is largely due to a decrease in emission of motor oil. For brick kilns, the forced draft zig-zag kilns had higher EF PM2.5 (12-19 g kg-1) compared to clamp kilns (8-13 g kg-1) and also exhibited chemical differences. PM2.5 emitted from the zig-zag kiln were mainly OC (7%), sulfate (32%) and uncharacterized chemical components (60%), while clamp kiln emissions were dominated by OC (64%) and ammonium sulfate (36%). The quantitative emission factors developed in this study may be used for source apportionment and to update regional emission inventories.

  7. The resonance self-shielding calculation with regularized random ladders

    International Nuclear Information System (INIS)

    Ribon, P.

    1986-01-01

    The straightforward method for calculation of resonance self-shielding is to generate one or several resonance ladders, and to process them as resolved resonances. The main drawback of Monte Carlo methods used to generate the ladders, is the difficulty of reducing the dispersion of data and results. Several methods are examined, and it is shown how one (a regularized sampling method) improves the accuracy. Analytical methods to compute the effective cross-section have recently appeared: they are basically exempt from dispersion, but are inevitably approximate. The accuracy of the most sophisticated one is checked. There is a neutron energy range which is improperly considered as statistical. An examination is presented of what happens when it is treated as statistical, and how it is possible to improve the accuracy of calculations in this range. To illustrate the results calculations have been performed in a simple case: nucleus 238 U, at 300 K, between 4250 and 4750 eV. (author)

  8. Creating a Professional Ladder for Interpreters for Improvement of Care.

    Science.gov (United States)

    Marshall, Lori; Fischer, Anna; Noyes Soeller, Allison; Cordova, Richard; Gutierrez, Yvonne R; Alford, Luis

    2016-01-01

    Children's Hospital Los Angeles (CHLA), a metropolitan academic medical center, recognized limitations in how the professional interpreters from the Diversity Services Department were used to support effective patient-provider communication across the organization. Given the importance of mitigating language and communication barriers, CHLA sought to minimize clinical and structural barriers to health care for limited English proficiency populations through a comprehensive restructuring of the Diversity Services Department. This approach entailed a new delivery model for hospital language assistance and cultural consultancy resources. The intervention focused on restructuring the Diversity Services Department, redefining priorities, reallocating resources, and redefining the roles of the language staff positions in the department. The language staff role was redesigned to fit a four-level professional career ladder modeled after the professional career ladders commonly used in hospitals for the RN role and other professional disciplines. The approach involved creating new levels of language specialist, each with progressive requirements for performance, leadership, and accountability for patient care outcomes. Language staff in the inpatient, clinic, and emergency department settings worked alongside nurses, physicians, and other disciplines to care for a specific set of patients. The result of this work was a positive culture change resulting in service efficiencies, care improvements, and improved access to language services. A professional career ladder for language staff contributed to improving the quality and access of language services and advancing the interpreting profession by incorporating care coordination support, vital document translation, and cultural consultancy.

  9. Ground Radio Operator Career Ladder AFSC 293X3.

    Science.gov (United States)

    1981-07-01

    formal resident training, OJT, and ,her Air Force management decisions . The structure of jobs within the Ground ! odio Operatoi career ladder was...33 ADJUST ANTENNA TUNING UNITS 33 TYPE RECORDS, REPORTS, OR FORMS :33 OPERATE AUXILLARY GENERATORS 33 A8 ’iT’ TASKS PERFORMED BY SUPERVISORS AND

  10. Structure of gold monoatomic wires connected to two electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Zoubkoff, Remi [Centre de Recherche en Matiere Condensee et Nanosciences, CNRS, Campus de Luminy, Case 913, 13288 Marseille Cedex 9 (France)]. E-mail: zoubkoff@crmcn.univ-mrs.fr; Vega, L. de la [Departamento de Fisica de la Materia Condensada C-V, Facultad de Ciencias, Universidad Autonoma de Madrid, E-28049 Madrid (Spain); Martin-Rodero, A. [Departamento de Fisica de la Materia Condensada C-V, Facultad de Ciencias, Universidad Autonoma de Madrid, E-28049 Madrid (Spain); Levy Yeyati, A. [Departamento de Fisica de la Materia Condensada C-V, Facultad de Ciencias, Universidad Autonoma de Madrid, E-28049 Madrid (Spain); Saul, Andres [Centre de Recherche en Matiere Condensee et Nanosciences, CNRS, Campus de Luminy, Case 913, 13288 Marseille Cedex 9 (France)

    2007-09-01

    In this work, we present calculations concerning the stability of infinite monoatomic Au wires and finite Au wires between electrodes. For the systems with the electrodes, that we represent by FCC slabs with (0 0 1) surfaces, the total energy calculations have been performed with a spd non-orthogonal tight-binding Hamiltonian. For the infinite wires, the calculations were also compared to semi-empirical and first principle ones. For the infinite wires and small enough inter-atomic distances, we find that a zig-zag structure is most stable than the linear one, in agreement with previous calculations. For the system between electrodes, one gets an almost concave or a symmetric broken edges structure depending on the inter-atomic distance.

  11. Diode-pumped glass laser (10 J X 10 HZ) development

    International Nuclear Information System (INIS)

    Tadashi Kanabe; Toshiyuki Kawashima; Masanobu Yamanaka; Masahiro Nakatsuka; Yasukazu Izawa; Takeshi Kanzaki; Hirofumi Kan; Sadao Nakai

    2002-01-01

    A high-energy, high beam quality, diode-pumped 1053-nm Nd:phosphate glass laser amplifier has been demonstrated in order to verify the conceptual design of HALNA (High Average-power Laser for Nuclear-fusion Application): a diode-pumped solid-state laser based on a water-cooled zig-zag slab optical geometry. This amplifier yielded 8.5 J output energy per pulse at 0.5 Hz in a 20 ns pulse of two times the diffraction limit beam quality with an optical-to-optical conversion efficiency of 10.9%. The experimental results revealed that the primary requirements for the IFE driver, such as diode-pumping, energy storage and extraction efficiencies, and beam quality have been fulfilled

  12. Range Sensor-Based Efficient Obstacle Avoidance through Selective Decision-Making.

    Science.gov (United States)

    Shim, Youngbo; Kim, Gon-Woo

    2018-03-29

    In this paper, we address a collision avoidance method for mobile robots. Many conventional obstacle avoidance methods have been focused solely on avoiding obstacles. However, this can cause instability when passing through a narrow passage, and can also generate zig-zag motions. We define two strategies for obstacle avoidance, known as Entry mode and Bypass mode. Entry mode is a pattern for passing through the gap between obstacles, while Bypass mode is a pattern for making a detour around obstacles safely. With these two modes, we propose an efficient obstacle avoidance method based on the Expanded Guide Circle (EGC) method with selective decision-making. The simulation and experiment results show the validity of the proposed method.

  13. Expandable esophageal metallic stents coating with silicone rubber: An experimental study in rabbits

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ho Young; Han, Young Min; Son, Myung Hee; Kim, Jong Soo; Choi, Ki Chul; Kuh, Ja Hong; Chae, Soo Wan [Chonbuk National University Medical School, Chonju (Korea, Republic of); Kim, Hak Nam [Chungju Lee Rha Hospital, Chungju (Korea, Republic of)

    1990-10-15

    To determine the effect of the expandable esophageal metallic stents on the esophagus, we constructed an expandable metallic stent. It was stainless steel wire formed in a zig-zag pattern in fully expanded diameter. Twenty stents were introduced in the normal esophagus through a 8.5 French-teflon sheath in 10 rabbits for 1 week to 12 weeks. Three out of the 20 stents migrated slightly. At 1 week after the placement of the stent, the mucosa partly revealed pressure necrosis and some regeneration, the muscle layer below the stent wires found compressed and thinned. At 8 weeks, the mucosa showed complete regeneration, and the stent wires were found covered by fibrous tissue.

  14. Range Sensor-Based Efficient Obstacle Avoidance through Selective Decision-Making

    Directory of Open Access Journals (Sweden)

    Youngbo Shim

    2018-03-01

    Full Text Available In this paper, we address a collision avoidance method for mobile robots. Many conventional obstacle avoidance methods have been focused solely on avoiding obstacles. However, this can cause instability when passing through a narrow passage, and can also generate zig-zag motions. We define two strategies for obstacle avoidance, known as Entry mode and Bypass mode. Entry mode is a pattern for passing through the gap between obstacles, while Bypass mode is a pattern for making a detour around obstacles safely. With these two modes, we propose an efficient obstacle avoidance method based on the Expanded Guide Circle (EGC method with selective decision-making. The simulation and experiment results show the validity of the proposed method.

  15. Development of diode-pumped solid-state laser HALNA for fusion reactor driver

    International Nuclear Information System (INIS)

    Kawashima, Toshiyuki; Kanabe, Tadashi; Matsumoto, Osamu

    2005-01-01

    The diode-pumped slab laser for inertial fusion energy driver has been demonstrated, which produces the 1053-nm output energy of 10 J at 10 Hz. The glass slab laser amplifier has been pumped by quasi-CW 290 kW AlGaAs laser-diode arrays at 803 nm. The optical system can compensate for thermal effects by use of zig-zag optical propagation, image-relayed telescope, and 45deg Faraday rotator. The output energy of 10.6 J at 1 Hz with the optical to optical conversion efficiency of 19.9% has been successfully obtained. Also the 10 Hz operation has been performed with a 5.1 J output energy. (author)

  16. High-energy, large-momentum-transfer processes: Ladder diagrams in φ3 theory. Pt. 1

    International Nuclear Information System (INIS)

    Osland, P.; Wu, T.T.; Harvard Univ., Cambridge, MA

    1987-01-01

    Relativistic quantum field theories may give us useful guidance to understanding high-energy, large-momentum-transfer processes, where the center-of-mass energy is much larger than the transverse momentum transfers, which are in turn much larger than the masses of the participating particles. With this possibility in mind, we study the ladder diagrams in φ 3 theory. In this paper, some of the necessary techniques are developed and applied to the simplest cases of the fourth- and sixth-order ladder diagrams. (orig.)

  17. Breathers in Josephson junction ladders: Resonances and electromagnetic wave spectroscopy

    DEFF Research Database (Denmark)

    Miroshnichenko, A. E.; Flach, S.; Fistul, M.

    2001-01-01

    We present a theoretical study of the resonant interaction between dynamical localized states (discrete breathers) and linear electromagnetic excitations (EE's) in Josephson junction ladders. By making use of direct numerical simulations we find that such an interaction manifests itself by resonant...

  18. 29 CFR Appendix A to Subpart X of... - Ladders

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Ladders A Appendix A to Subpart X of Part 1926 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... designed and built in accordance with the applicable national consensus standards, as set forth below, will...

  19. 46 CFR 116.438 - Stairtowers, stairways, ladders, and elevators.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Stairtowers, stairways, ladders, and elevators. 116.438 Section 116.438 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150 PASSENGERS OR WITH OVERNIGHT ACCOMMODATIONS FOR MORE THAN 49 PASSENGERS CONSTRUCTION AND ARRANGEMENT Fire Protection §...

  20. Cutting and dismantling of the South West ladder of the Atucha I nuclear power plant

    International Nuclear Information System (INIS)

    Anasco, Roberto

    2006-01-01

    The metallic ladder built in stainless steel was used originally to check the welding of the reactor pressure vessel. It was located between the thermal insulation and reactor pressure vessel. Because of a failure in the mechanism, which let the ladder runs around the vessel, it had to be removed. A special tool remotely operated was designed to make different cuts in the bottom of the structure in a very high radioactive location [es

  1. Structural aspects of the zygotic embryogenesis of Acca sellowiana (O. Berg Burret (Myrtaceae Aspectos estruturais da embriogênese zigótica em Acca sellowiana (O. Berg Burret (Myrtaceae

    Directory of Open Access Journals (Sweden)

    Rosete Pescador

    2009-03-01

    Full Text Available Acca sellowiana has anatropous, bitegmic and crassinucellate ovules. The outer and inner integuments are double-layered except in the micropyle, where they are composed of more layers; the micropyle is zig-zag shaped. The egg apparatus lies at the micropylar pole, and the zynergids present a conspicuous filiform apparatus. The antipodal cells are present in the chalazal region, persisting before the occurrence of double fertilization. The zygote is visible 21 days after pollination; nuclear endosperm is already present. The first mitotic division of the zygote occurs at 24th day. The globular, cordiform and torpedo embryo stages can be seen at 30, 45 and 60 days after pollination, respectively. The mature embryo characterized by the presence of a well-developed hypocotyl-radicular axis with two fleshy and folded cotyledons was observed 120 days after pollination. Endosperm is absent in the seeds, and the embryo has spiral form, characteristic of Myrtinae. The zygotic embryology studies of A. sellowiana indicate that this species has embryological characteristics which are in agreement with those reported for Myrtaceae (Myrteae, Myrtinae, and also broaden the knowledge about the sexual reproduction of this native species, whose commercial cultivation has been growing.Acca sellowiana apresenta óvulos anátropos, bitegumentados e crassinucelados. Os tegumentos externo e interno são constituídos por duas camadas de células, exceto na região da micrópila em que têm maior número de camadas; a micrópila apresenta-se em ziguezague. O aparelho oosférico ocupa a região micropilar com sinérgides apresentando aparato fibrilar conspícuo. Na região calazal, as três antípodas estão presentes antes da ocorrência da dupla fecundação. O zigoto é formado 21 dias após a polinização controlada, e o endosperma do tipo nuclear já está presente. O zigoto sofre a primeira divisão mitótica no 24º dia. Embriões nas fases globular, cordiforme

  2. New insights into the origin of ladder dikes: Implications for punctuated growth and crystal accumulation in the Cathedral Peak granodiorite

    Science.gov (United States)

    Wiebe, R. A.; Jellinek, A. M.; Hodge, K. F.

    2017-04-01

    Ladder dikes are steep tabular bodies, typically a meter or less thick, composed of moderately dipping, concave upward, alternating dark (i.e. schlieren) and light bands oriented roughly perpendicular to the ladder dike margins. These structures occur widely but sparsely in granitic rocks and are found prominently in the Cathedral Peak granodiorite (CPG) of the Tuolumne Intrusive suite. Previous studies have interpreted that ladder dikes form as a result of processes including the downward flow of crystal mush in cracks within strong crystal mush or by upward flow in steep tubes that migrate within a strong crystal mush. Our new observations indicate that ladder dikes formed by downward flow of crystal mush in troughs or valleys, in a manner potentially comparable to trough bands in mafic layered intrusions. Extensions of the schlieren outward and upward away from the ladder dike margins into the host granite demonstrate that the host granite was deposited as mounds on both sides at the same time as the ladder dikes. Ladder dikes, therefore, record lateral flows of crystal mush on a magma chamber floor. Vertical exposures suggest these flows are on the order of ten meters thick. Some steep exposures on granite domes indicate multiple ladder dikes (and flows) over a stratigraphic height of 80-100 m. Later (stratigraphically higher) flows commonly deform and erode the top of an earlier flow, and granitic material rich in K-feldspar megacrysts has locally engulfed large blocks of ladder dikes, demonstrating that the megacrysts were also transported in flows. Flows in the CPG are directed away from the center of the pluton toward the western and eastern margins and apparently spread along a strong crystal mush floor and into a rheologically complex CPG magma. Whereas established dynamical models for spreading (single phase) gravity currents with simple and complex rheologies explain the elongate geometry, spacing and orientation of the tabular bodies, the origin and

  3. The Design of Smart Home for the Elderly Based on ZigBee

    Directory of Open Access Journals (Sweden)

    He Junhan

    2016-01-01

    Full Text Available In recent years, as the pace of people’s life is speeding up, more young people working far from their parents, the elderly have to live alone. With the increase of age, they tend to forget things which may create safety accidents. Therefore, a smart home system for the elderly will have good application prospects. In this paper, a smart system based on ZigBee wireless network is proposed. This system uses wireless network for transmitting information between sensor nodes and uses embedded technology to analyse the data. Once an emergency occurs, the system will send an alarm to notify the elderly. At the same time, the young people can know the situation of the house through mobile phone

  4. “Why Caipirinha?”- The Online via Chat Laddering Technique CAN Answer

    Directory of Open Access Journals (Sweden)

    Bruno Bordeaux-Rego

    2011-04-01

    Full Text Available As customers are becoming increasingly connected to the internet, this means that they are available for online interviews, thus opening up a space for investigating research methods, especially qualitative research, in an attempt to identify how to adapt data collecting instruments to the so-called “connected customer era”. In this context, the focus of this article is on the application viability analysis of the laddering technique used online and in real-time chat by asking the following question: “Why caipirinha?”. Conducting online in-depth interviews through the MSN Messenger and Skype (the most commonly used chat tools in Brazil, 23 attributes, 22 consequences and 13 values were identified, resulting in 133 ladders, 71 of which reached the value level. Along with friends/mates, Integration, Entertainment and Fun, in addition to Alcohol, Insouciance/ relaxation and Pleasure constitute the most frequent ladders. Concerning the application itself, the participants gave positive feedback, even though some of them did not feel satisfied because they became tired. Convenience, objectivity, disinhibition, easy scheduling and flexibility were identified. The viability of online in-depth interviewing via real-time chats was confirmed, raising the question of the possibility of it achieving other qualitative research techniques.

  5. Qualitative and Quantitative Security Analyses for ZigBee Wireless Sensor Networks

    DEFF Research Database (Denmark)

    Yuksel, Ender

    methods and techniques in different areas and brings them together to create an efficient verification system. The overall ambition is to provide a wide range of powerful techniques for analyzing models with quantitative and qualitative security information. We stated a new approach that first verifies...... applications, home automation, and traffic control. The challenges for research in this area are due to the unique features of wireless sensor devices such as low processing power and associated low energy. On top of this, wireless sensor networks need secure communication as they operate in open fields...... low level security protocol s in a qualitative manner and guarantees absolute security, and then takes these verified protocols as actions of scenarios to be verified in a quantitative manner. Working on the emerging ZigBee wireless sensor networks, we used probabilistic verification that can return...

  6. Generalized ladder operators for the Dirac-Coulomb problem via SUSY QM

    International Nuclear Information System (INIS)

    Rodrigues, R. de Lima; Universidade Federal de Campina Grande, PB

    2003-12-01

    The supersymmetry in quantum mechanics and shape invariance condition are applied as an algebraic method to solving the Dirac-Coulomb problem. The ground state and the excited states are investigated via new generalized ladder operators. (author)

  7. Orbital currents and charge density waves in a generalized Hubbard ladder

    International Nuclear Information System (INIS)

    Fjaerestad, J.O.; Marston, J.B.; Schollwoeck, U.

    2006-01-01

    We study a generalized Hubbard model on the two-leg ladder at zero temperature, focusing on a parameter region with staggered flux (SF)/d-density wave (DDW) order. To guide our numerical calculations, we first investigate the location of a SF/DDW phase in the phase diagram of the half-filled weakly interacting ladder using a perturbative renormalization group (RG) and bosonization approach. For hole doping δ away from half-filling, finite-system density-matrix renormalization-group (DMRG) calculations are used to study ladders with up to 200 rungs for intermediate-strength interactions. In the doped SF/DDW phase, the staggered rung current and the rung electron density both show periodic spatial oscillations, with characteristic wavelengths 2/δ and 1/δ, respectively, corresponding to ordering wavevectors 2k F and 4k F for the currents and densities, where 2k F = π (1 - δ). The density minima are located at the anti-phase domain walls of the staggered current. For sufficiently large dopings, SF/DDW order is suppressed. The rung density modulation also exists in neighboring phases where currents decay exponentially. We show that most of the DMRG results can be qualitatively understood from weak-coupling RG/bosonization arguments. However, while these arguments seem to suggest a crossover from non-decaying correlations to power-law decay at a length scale of order 1/δ, the DMRG results are consistent with a true long-range order scenario for the currents and densities

  8. Rancang Bangun Instrumen Sistem Buoy Menggunakan A-Wsn Protokol Zigbee Untuk Pengamatan Ekosistem Pesisir (Development of Buoy System Instrument using A-WSN ZigBee Protocol for Coastal Ecosystem Monitoring

    Directory of Open Access Journals (Sweden)

    Acta Withamana

    2013-12-01

    Full Text Available Luasnya perairan dan lingkungan laut yang tidak bersahabat menimbulkan tantangan tersendiri untuk diobservasi. Aktivitas observasi secara konvensional di laut, yang menggunakan kapal sebagai wahana bergerak, membutuhkan biaya yang tinggi dan tidak efisien untuk memperoleh resolusi spasial dan temporal yang diinginkan. Buoy tertambat telah lama digunakan sebagai salah satu pilihan untuk aktivitas observasi laut. Namun ukuran yang besar dari rancangan buoy yang ada pada umumnya tidak cocok untuk pengamatan ekosistem pesisir. Perkembangan teknologi semikonduktor yang pesat melahirkan konsep wireless sensor network (WSN. Komunikasi protokol ZigBee memiliki kelebihan penggunaan energi yang efisien dan kemudahan pemasangan. Riset ini dilakukan untuk mengembangkan instrumen buoy tertambat dan menguji apakah WSN dapat diaplikasikan di wilayah pesisir. Buoy tertambat yang dikembangkan memiliki kinerja yang baik dan stabil sebagai wahana instrumen. Kinerja jaringan ZigBee menunjukan tingkat keberhasilan pengiriman data sebesar 100% pada uji coba statis. Menggunakan empat buah baterai NiMH, instrumen ini dapat bekerja selama kurang lebih 39 jam untuk coordinator dan router, serta 89 jam untuk end device. Pengujian di lapangan menunjukan hasil terburuk sebesar 84.94% keberhasilan pengiriman data pada E1, dan hasil terbaik sebesar 100% keberhasilan pengiriman data pada R1 dan E3. Data suhu permukaan laut yang diterima juga dapat menggambarkan sebaran suhu permukaan di Pulau Panggang. Hasil penelitian memberikan gambaran bahwa Instrumen Sistem Buoy Menggunakan A-Wsn Protokol Zigbee sangat berpotensi untuk digunakan dalam pengamatan ekosistem pesisir. Kata kunci: instrumen, buoy tertambat, ZigBee, suhu permukaan laut, observasi pesisir   Ocean observation has become a challenge due to its vast and rough condition. The conventional observation, for example using ship as a mobile platform, is very expensive and inefficient to obtain desired spatial and temporal

  9. Quivers, YBE and 3-manifolds

    Science.gov (United States)

    Yamazaki, Masahito

    2012-05-01

    We study 4d superconformal indices for a large class of {N} = 1 superconformal quiver gauge theories realized combinatorially as a bipartite graph or a set of "zig-zag paths" on a two-dimensional torus T 2. An exchange of loops, which we call a "double Yang-Baxter move", gives the Seiberg duality of the gauge theory, and the invariance of the index under the duality is translated into the Yang-Baxter-type equation of a spin system defined on a "Z-invariant" lattice on T 2. When we compactify the gauge theory to 3d, Higgs the theory and then compactify further to 2d, the superconformal index reduces to an integral of quantum/classical dilogarithm functions. The saddle point of this integral unexpectedly reproduces the hyperbolic volume of a hyperbolic 3-manifold. The 3-manifold is obtained by gluing hyperbolic ideal polyhedra in {{H}^3} , each of which could be thought of as a 3d lift of the faces of the 2d bipartite graph. The same quantity is also related with the thermodynamic limit of the BPS partition function, or equivalently the genus 0 topological string partition function, on a toric Calabi-Yau manifold dual to quiver gauge theories. We also comment on brane realization of our theories. This paper is a companion to another paper summarizing the results [1].

  10. SUSY’s Ladder: reframing sequestering at Large Volume

    Energy Technology Data Exchange (ETDEWEB)

    Reece, Matthew [Department of Physics, Harvard University,Cambridge, MA 02138 (United States); Xue, Wei [Center for Theoretical Physics, Massachusetts Institute of Technology,Cambridge, MA 02139 (United States)

    2016-04-07

    Theories with approximate no-scale structure, such as the Large Volume Scenario, have a distinctive hierarchy of multiple mass scales in between TeV gaugino masses and the Planck scale, which we call SUSY’s Ladder. This is a particular realization of Split Supersymmetry in which the same small parameter suppresses gaugino masses relative to scalar soft masses, scalar soft masses relative to the gravitino mass, and the UV cutoff or string scale relative to the Planck scale. This scenario has many phenomenologically interesting properties, and can avoid dangers including the gravitino problem, flavor problems, and the moduli-induced LSP problem that plague other supersymmetric theories. We study SUSY’s Ladder using a superspace formalism that makes the mysterious cancelations in previous computations manifest. This opens the possibility of a consistent effective field theory understanding of the phenomenology of these scenarios, based on power-counting in the small ratio of string to Planck scales. We also show that four-dimensional theories with approximate no-scale structure enforced by a single volume modulus arise only from two special higher-dimensional theories: five-dimensional supergravity and ten-dimensional type IIB supergravity. This gives a phenomenological argument in favor of ten dimensional ultraviolet physics which is different from standard arguments based on the consistency of superstring theory.

  11. Applications of ZigBee Technology in the Safety Monitoring System of Low Gas Pipeline Transportation

    Directory of Open Access Journals (Sweden)

    Wei Deyu

    2015-01-01

    Full Text Available The existing safety monitoring system of low gas pipeline transportation establishes a wired communication network monitoring system mainly on the basis of industrial bus. It has problems such as large transmission signal attenuation, complex wiring, high-labor intensity, inconvenient installation and maintenance, high maintenance cost, and so on. Featuring low cost, power-saving, reliability, stability and flexibility, the wireless sensor network established by ZigBee wireless communication technology can realize the real-time all-dimensional dynamic monitoring on parameters of low gas pipeline transportation system and overcome the shortcomings and deficiencies of wired network system.

  12. End States, Ladder Compounds, and Domain-Wall Fermions

    International Nuclear Information System (INIS)

    Creutz, M.

    1999-01-01

    A magnetic field applied to a cross-linked ladder compound can generate isolated electronic states bound to the ends of the chain. After exploring the interference phenomena responsible, I discuss a connection to the domain-wall approach to chiral fermions in lattice gauge theory. The robust nature of the states under small variations of the bond strengths is tied to chiral symmetry and the multiplicative renormalization of fermion masses. copyright 1999 The American Physical Society

  13. Intrinsic and extrinsic spin Hall effects of Dirac electrons

    International Nuclear Information System (INIS)

    Fukazawa, Takaaki; Kohno, Hiroshi; Fujimoto, Junji

    2017-01-01

    We investigate the spin Hall effect (SHE) of electrons described by the Dirac equation, which is used as an effective model near the L-points in bismuth. By considering short-range nonmagnetic impurities, we calculate the extrinsic as well as intrinsic contributions on an equal footing. The vertex corrections are taken into account within the ladder type and the so-called skew-scattering type. The intrinsic SHE which we obtain is consistent with that of Fuseya et al. It is found that the extrinsic contribution dominates the intrinsic one when the system is metallic. The extrinsic SHE due to the skew scattering is proportional to Δ/n i u, where 2Δ is the band gap, n i is the impurity concentration, and u is the strength of the impurity potential. (author)

  14. Local magnetic susceptibility, spin dynamics, and charge order in the quasi-one-dimensional conductor β -Li0.33V2O5 investigated by site-selective 51V NMR

    Science.gov (United States)

    Yamauchi, Ichihiro; Itoh, Masayuki; Yamauchi, Touru; Yamaura, Jun-Ichi; Ueda, Yutaka

    2017-11-01

    51V NMR measurements have been conducted on a single crystal of the quasi-one-dimensional conductor β -Li0.33V2O5 which undergoes a metal-insulator (MI) transition at TMI˜170 K. In the metallic phase, we obtain 51V Knight shift and electric field gradient tensors. From the analysis of the 51V Knight shifts, we find that the charge disproportionation appears even in the metallic state and the electronic structure is represented within a model of weakly coupled ladders containing two types of ladders with distinct carrier densities. Based on the 51V nuclear spin-lattice relaxation rate, we discuss the spin dynamics within the one-dimensional electron gas model. From the analysis of several nonmagnetic V5 + spectra observed in the insulating phase, we propose a possible charge-order pattern which has a superlattice modulation larger than those in other family members of β -A0.33V2O5 (A =Na and Ag). Finally, we discuss the A -ion dependence of the electronic structure, the charge disproportionation, and the charge order in β -A0.33V2O5 .

  15. Gluon ladders in pp (pp-bar) collisions

    International Nuclear Information System (INIS)

    Machado, Magno Valerio Trindade; Ducati, Maria Beatriz Gay

    2000-01-01

    Full text follows: We study the contribution of a finite sum of gluon ladders to the hadronic processes showing that a reliable description is obtained using two order on perturbation theory. The pp(pp-bar) total cross sections are described with good agreement, consistent with unitarity bound. We also calculate the elastic scattering amplitude at non zero momentum transfer t, introducing two distinct Ansatz for the proton impact factor. As a by product the elastic differential cross section is obtained at small t approximation and compared with the data. (author)

  16. Interband optical absorption in the Wannier-Stark ladder under the electron-LO-phonon resonance condition

    International Nuclear Information System (INIS)

    Govorov, A.O.

    1993-08-01

    Interband optical absorption in the Wannier-Stark ladder in the presence of the electron-LO-phonon resonance is investigated theoretically. The electron-LO-phonon resonance occurs when the energy spacing between adjacent Stark-ladder levels coincides with the LO-phonon energy. We propose a model describing the polaron effect in a superlattice. Calculations show that the absorption line shape is strongly modified due to the polaron effect under the electron-LO-phonon resonance condition. We consider optical phenomena in a normal magnetic field that leads to enhancement of polaron effects. (author). 17 refs, 5 figs

  17. The crystal structure of gustavite, PbAgBi3S6. Analysis of twinning and polytypism using the OD approach

    DEFF Research Database (Denmark)

    Makovicky, Emil; Topa, Dan

    2011-01-01

    ) of the opposite species; the latter is explained by a presence of twin lamellae or antiphase domains in the crystal. In accordance with its frequently observed twinning, gustavite is an OD (order-disorder) structure that can be described by zig-zag unit layers with layer symmetry P(2/n) 21/c 2/m...... and the interlayer symmetry elements {(22/n1,1/2) 21/n1/2,2 21/2/ a2}. An alternative OD description uses planar unit layers with the layer symmetry P(2/ b) 21/c 21/m and the interlayer elements 22/n1,–1/2 21/n1/2,2 21/2/a2. The former description adheres closely to the details of coordination of bismuth observed...

  18. Catalytic behavior of ‘Pt-atomic chain encapsulated gold nanotube’: A density functional study

    Energy Technology Data Exchange (ETDEWEB)

    Nigam, Sandeep, E-mail: snigam@barc.gov.in; Majumder, Chiranjib [Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

    2016-05-23

    With an aim to design novel material and explore its catalytic performance towards CO oxidation, Pt atomic chain was introduced inside gold nanotube (Au-NT). Theoretical calculations at the level of first principles formalism was carried out to investigate the atomic and electronic properties of the composite. Geometrically Pt atoms prefer to align in zig-zag fashion. Significant electronic charge transfer from inside Pt atoms to the outer wall Au atoms is observed. Interaction of O{sub 2} with Au-NT wall follows by injection of additional electronic charge in the anti-bonding orbital of oxygen molecule leading to activation of the O-O bond. Further interaction of CO molecule with the activated oxygen molecule leads to spontaneous oxidation reaction and formation of CO{sub 2}.

  19. Recurrent variational approach to the two-leg Hubbard ladder

    International Nuclear Information System (INIS)

    Kim, E.H.; Sierra, G.; Duffy, D.

    1999-01-01

    We applied the recurrent variational approach to the two-leg Hubbard ladder. At half filling, our variational ansatz was a generalization of the resonating valence-bond state. At finite doping, hole pairs were allowed to move in the resonating valence-bond background. The results obtained by the recurrent variational approach were compared with results from density matrix renormalization group. copyright 1999 The American Physical Society

  20. Resonant states and wavepacket super-diffusion in intra-chain correlated ladders with diluted disorder

    International Nuclear Information System (INIS)

    De Moura, F A B F; Leao, F F S; Lyra, M L

    2011-01-01

    In this work, we study a tight-binding Hamiltonian model system of a binary correlated ladder with diluted disorder. We introduce intra-chain correlations between the on-site potentials by imposing that ε i, s = - ε i,-s where s = ± 1 indexes the two ladder chains. Further, we consider each ladder chain as composed of inter-penetrating ordered and random sub-chains. We show that the presence of a random on-site distribution in one of the inter-penetrating chains leads to Anderson localization except at a specific symmetric pair of energy eigenmodes. Further, by integrating the time-dependent Schroedinger equation, we follow the time-evolution of an initially localized one-electron wavepacket. We report that the remaining delocalized resonant modes are responsible for a super-diffusive spread of the wavepacket dispersion while the wavepacket participation function remains finite. A scaling analysis of the wavepacket distribution shows that it obeys a universal scaling form with the development of a power-law tail followed by a super-diffusively evolving cutoff. We obtain three exponents characterizing this super-diffusive dynamics and show that they satisfy a simple scaling relation.

  1. Modification of the Ladder Rung Walking Task—New Options for Analysis of Skilled Movements

    Directory of Open Access Journals (Sweden)

    Iwa Antonow-Schlorke

    2013-01-01

    Full Text Available Method sensitivity is critical for evaluation of poststroke motor function. Skilled walking was assessed in horizontal, upward, and downward rung ladder walking to compare the demands of the tasks and test sensitivity. The complete step sequence of a walk was subjected to analysis aimed at demonstrating the walking pattern, step sequence, step cycle, limb coordination, and limb interaction to complement the foot fault scoring system. Rats (males, n=10 underwent unilateral photothrombotic lesion of the motor cortex of the forelimb and hind limb areas. Locomotion was video recorded before the insult and at postischemic days 7 and 28. Analysis of walking was performed frame-by-frame. Walking along the rung ladder revealed different results that were dependent on ladder inclination. Horizontal walking was found to discriminate lesion-related motor deficits in forelimb, whereas downward walking demonstrates hind limb use most sensitively. A more frequent use of the impaired forelimb that possibly supported poststroke motor learning in rats was shown. The present study provides a novel system for a detailed analysis of the complete walking sequence and will help to provide a better understanding of how rats deal with motor impairments.

  2. A general procedure to evaluate many-body spin operator amplitudes from periodic calculations: application to cuprates

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Iberio de P R [Departament de Quimica Fisica and Institut de Quimica Teorica i Computacional (IQTCUB), Universitat de Barcelona and Parc CientIfic de Barcelona, C/ MartI i Franques 1, E-08028 Barcelona (Spain); Calzado, Carmen J [Departamento de Quimica Fisica, Universidad de Sevilla, C/ Prof. GarcIa Gonzalez s/n, E-41012 Sevilla (Spain); Malrieu, Jean-Paul [IRSAMC, Laboratoire de Physique Quantique, Universite Paul Sabatier, 118 Route de Narbonne, F-31062 Toulouse-Cedex (France); Illas, Francesc [Departament de Quimica Fisica and Institut de Quimica Teorica i Computacional (IQTCUB), Universitat de Barcelona and Parc CientIfic de Barcelona, C/ MartI i Franques 1, E-08028 Barcelona (Spain)

    2007-10-15

    A general procedure is presented which permits the form of an extended spin Hamiltonian to be established for a given magnetic solid and the magnitude of its terms to be evaluated from spin polarized, Hartree-Fock or density functional calculations carried out for periodic models. The computational strategy makes use of a general mapping between the energy of pertinent broken-symmetry solutions and the diagonal terms of the spin Hamiltonian in a local representation. From this mapping it is possible to determine not only the amplitude of the well-known two-body magnetic coupling constants between near-neighbor sites, but also the amplitudes of four-body cyclic exchange terms. A scrutiny of the on-site spin densities provides additional information and control of the many broken-symmetry solutions which can be found. The procedure is applied to the La{sub 2}CuO{sub 4}, Sr{sub 2}CuO{sub 2}F{sub 2}, Sr{sub 2}CuO{sub 2}Cl{sub 2} and Ca{sub 2}CuO{sub 2}Cl{sub 2} square lattices and the SrCu{sub 2}O{sub 3} ladder compound. It is shown that a proper description of the magnetic structure of these compounds requires that two- and four-body terms are explicitly included in the spin Hamiltonian. The implications for the interpretation of recent experiments are discussed.

  3. Multi-material size optimization of a ladder frame chassis

    Science.gov (United States)

    Baker, Michael

    The Corporate Average Fuel Economy (CAFE) is an American fuel standard that sets regulations on fuel economy in vehicles. This law ultimately shapes the development and design research for automakers. Reducing the weight of conventional cars offers a way to improve fuel efficiency. This research investigated the optimality of an automobile's ladder frame chassis (LFC) by conducting multi-objective optimization on the LFC in order to reduce the weight of the chassis. The focus of the design and optimization was a ladder frame chassis commonly used for mass production light motor vehicles with an open-top rear cargo area. This thesis is comprised of two major sections. The first looked to perform thickness optimization in the outer walls of the ladder frame. In the second section, many multi-material distributions, including steel and aluminium varieties, were investigated. A simplified model was used to do an initial hand calculation analysis of the problem. This was used to create a baseline validation to compare the theory with the modeling. A CAD model of the LFC was designed. From the CAD model, a finite element model was extracted and joined using weld and bolt connectors. Following this, a linear static analysis was performed to look at displacement and stresses when subjected to loading conditions that simulate harsh driving conditions. The analysis showed significant values of stress and displacement on the ends of the rails, suggesting improvements could be made elsewhere. An optimization scheme was used to find the values of an all steel frame an optimal thickness distribution was found. This provided a 13% weight reduction over the initial model. To advance the analysis a multi-material approach was used to push the weight savings even further. Several material distributions were analyzed and the lightest utilized aluminium in all but the most strenuous subjected components. This enabled a reduction in weight of 15% over the initial model, equivalent to

  4. THE PAN-STARRS 1 PHOTOMETRIC REFERENCE LADDER, RELEASE 12.01

    International Nuclear Information System (INIS)

    Magnier, E. A.; Tonry, J. L.; Burgett, W. S.; Chambers, K. C.; Flewelling, H. A.; Kaiser, N.; Kudritzki, R.-P.; Morgan, J. S.; Sweeney, W. E.; Schlafly, E.; Finkbeiner, D.; Juric, M.; Stubbs, C. W.; Price, P. A.

    2013-01-01

    As of 2012 January 21, the Pan-STARRS 1 3π Survey has observed the 3/4 of the sky visible from Hawaii with a minimum of 2 and mean of 7.6 observations in five filters, g P1 , r P1 , i P1 , z P1 , y P1 . Now at the end of the second year of the mission, we are in a position to make an initial public release of a portion of this unprecedented data set. This article describes the PS1 Photometric Ladder, Release 12.01. This is the first of a series of data releases to be generated as the survey coverage increases and the data analysis improves. The Photometric Ladder has rungs every hour in right ascension and at four intervals in declination. We will release updates with increased area coverage (more rungs) from the latest data set until the PS1 survey and the final re-reduction are completed. The currently released catalog presents photometry of ∼1000 objects per square degree in the rungs of the ladder. Saturation occurs at g P1 , r P1 , i P1 ∼ 13.5; z P1 ∼ 13.0; and y P1 ∼ 12.0. Photometry is provided for stars down to g P1 , r P1 , i P1 ∼ 19.1 in the AB system. This data release depends on the rigid 'Ubercal' photometric calibration using only the photometric nights, with systematic uncertainties of (8.0, 7.0, 9.0, 10.7, 12.4) mmag in (g P1 , r P1 , i P1 , z P1 , y P1 ). Areas covered only with lower quality nights are also included, and have been tied to the Ubercal solution via relative photometry; photometric accuracy of the non-photometric regions is lower and should be used with caution.

  5. Improving energy and carbon management in construction and civil engineering companies—evaluating the impacts of the CO2 Performance Ladder

    NARCIS (Netherlands)

    Rietbergen, Martijn G.; Opstelten, Ivo J.; Blok, Kornelis

    In the Netherlands, the CO2 Performance Ladder has been introduced as an energy management programme to facilitate continuous energy efficiency and carbon performance improvement in non-industrial sectors. This paper addresses the question: ‘What is the impact of the CO2 Performance Ladder on

  6. Design of Wireless Point of Sale Based on ZigBee Technology

    Directory of Open Access Journals (Sweden)

    Xiaoning Jiang

    2014-02-01

    Full Text Available With the rapid development of Point of Sale technology and modern communication technology, financial Point of Sale terminal system has been started from wired to wireless. Wireless payment technology can used where can’t rely on or even no cable network. As one of the most important technologies in the information era, Wireless Sensor Network has been widely used in banking business and other various modem business fields. This paper describes a kind of simple portable Point of Sale terminal based on the ZigBee wireless network 1, which is a low power, low cost, flexible, safe and reliable network. This Point of Sale system can be applied gas stations, liquefied petroleum gas stations and other complex sales environment, and it improves safety of gas station and personnel safety. Simple and user-friendly, this formula design and optimization method greatly improves efficiency and thus has much value for practical application.

  7. Parents' Participation on School Councils Analysed through Arnstein's Ladder of Participation

    Science.gov (United States)

    Stelmach, Bonnie

    2016-01-01

    Although parent school councils are the archetypal arrangement for engaging parents in school improvement planning, their effectiveness is negligible when it comes to building parents' capacity for and confidence in educational decision-making. Using Arnstein's ladder of citizen participation, this qualitative case study investigated the nature…

  8. Antiferromagnetic order in the ladder compound SrCu{sub 2}O{sub 3}: Cu-NMR/NQR measurements

    Energy Technology Data Exchange (ETDEWEB)

    Ohsugi, S.; Kitaoka, Y.; Azuma, M.; Fujishiro, Y.; Takano, M.

    1999-12-01

    The authors carried out the extensive Cu-nuclear magnetic and quadrupole resonance (NMR/NQR) experiments on the Zn(Ni)-doped ladder compound SrCu{sub 2}O{sub 3} (Sr123), Sr(Cu{sub 1{minus}x}M{sub x}){sub 2}O{sub 3} (M = Zn and Ni) with x {le} 0.02 and the La-doped Sr123, Sr{sub 1{minus}x}La{sub x}Cu{sub 2}O{sub 3} with {alpha} {le} 0.03. A spin-correlation length {xi}{sub s}/a (a: the lattice spacing between the Cu sites along the leg) of nonmagnetic impurity-induced staggered polarization (IISP) estimated from a quasi-one-dimensional (Q1D) IISP along the two legs in the 0.1--2% Zn-doped Sr123 was found to be independent of temperature (T) and scaled to an mean impurity distance D{sub AV} with the relation of {xi}{sub s}/a = 2.5 + D{sub AV}. The {xi}{sub s}/a's are much longer in x = 0.001 ({xi}{sub s}/a {approximately} 50) and 0.005 ({xi}{sub s}/a {approximately} 12) than an instantaneous spin-correlation length {xi}{sub 0}/a {approximately} 3--8 in Sr123. The formula of Neel T, T{sub N} (WC-Q1D) = J exp({minus}D{sub AV}/({xi}{sub s}/a)) (J = 2,000 K) based on the weakly interladder-coupled (WC) Q1D model explains the experimental T{sub N} values quantitatively.

  9. Bethe-Salpeter equation for fermion-antifermion system in the ladder approximation

    International Nuclear Information System (INIS)

    Fukui, Ichio; Seto, Noriaki; Yoshida, Toshihiro.

    1977-01-01

    The Bethe-Salpeter (B-S) equation is important for studying hadron physics. Especially intensive investigation on the fermion-antifermion B-S equation is indispensable for the phenomenological studies of hardrons. However, many components of the B-S amplitude and the Wick-rotated integral kernel of non-Fredholm type have prevented from knowing details the solutions even in the ladder approximation. Some particular solutions are known in case of the vanishing four-momenta of bound states. The B-S equation for the bound state of fermion-anti-fermion system interacting through vector (axial-vector) particle exchange was studied in the ladder approximation with Feynman gauge. The reduced equations were obtained for suitably decomposed amplitude, and it is shown that, in the S-wave case, the coupled equations separate into two parts. In the nonrelativistic limit, large components of the amplitude satisfy the Wick-Cutkosky equation, and small components are expressed in terms of the large ones. Equations are derived for the equal-time amplitudes. (Kobatake, H.)

  10. Measurement of the Rise-Time in a Single Sided Ladder Detector

    International Nuclear Information System (INIS)

    Gerber, C.E.

    1997-01-01

    In this note we report on the measurement of the preamplifier output rise time for a SVXII chip mounted on a D0 single sided ladder. The measurements were performed on the ladder 001-883-L, using the laser test stand of Lab D. The rise time was measured for different values of the response (or bandwidth) of the preamplifier. As a bigger bandwidth results in longer rise times and therefore in less noise, the largest possible bandwidth consistent with the time between bunch crossings should be chosen to operate the detectors. The rise time is defined as the time elapsed between 10% and 90% of the charge is collected. It is also interesting to measure the time for full charge collection and the percentage of charge collected in 132 ns and 396 ns. The results are shown in table 1, for bandwidths between 2 and 63 (binary numbers). The uncertainty on the time measurement is considered to be ∼ 10 ns. Figure 1 schematically defines the four quantities measured: rise time, time of full charge collection, and percentage of charge collected in 132 ns and 396 ns. Figures 2 to 8 are the actual measurements for bandwidths of 2, 4, 8, 12, 24, 32 and 63. Figure 9 is a second measurement for BW=24, used as a consistency check of the system and the time measurement performed on the plots. The data indicate that the single sided ladders can be operated at BW=63 for 396 ns and BW=12 for 132 ns, achieving full charge collection. This will result in smaller noise than originally anticipated.

  11. Surface Acoustic Analog of Bloch Oscillations, Wannier-Stark Ladders and Landau-Zener Tunneling

    Science.gov (United States)

    de Lima, M. M.; Kosevich, Yu. A.; Santos, P. V.; Cantarero, A.

    2011-12-01

    In this contribution, we discuss the recent experimental demonstration of Wannier-Stark ladders, Bloch Oscillations and Landau Zener tunneling in a solid by means of surface acoustic waves propagating through perturbed grating structures.

  12. Electric field induced localization phenomena in a ladder network with superlattice configuration: Effect of backbone environment

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, Paramita; Karmakar, S. N. [Condensed Matter Physics Division, Saha Institute of Nuclear Physics, Sector-I, Block-AF, Bidhannagar, Kolkata-700 064 (India); Maiti, Santanu K., E-mail: santanu.maiti@isical.ac.in [Physics and Applied Mathematics Unit, Indian Statistical Institute, 203 Barrackpore Trunk Road, Kolkata-700 108 (India)

    2014-09-15

    Electric field induced localization properties of a tight-binding ladder network in presence of backbone sites are investigated. Based on Green's function formalism we numerically calculate two-terminal transport together with density of states for different arrangements of atomic sites in the ladder and its backbone. Our results lead to a possibility of getting multiple mobility edges which essentially plays a switching action between a completely opaque to fully or partly conducting region upon the variation of system Fermi energy, and thus, support in fabricating mesoscopic or DNA-based switching devices.

  13. Using a familiar risk comparison within a risk ladder to improve risk understanding by low numerates: a study of visual attention.

    Science.gov (United States)

    Keller, Carmen

    2011-07-01

    Previous experimental research provides evidence that a familiar risk comparison within a risk ladder is understood by low- and high-numerate individuals. It especially helps low numerates to better evaluate risk. In the present study, an eye tracker was used to capture individuals' visual attention to a familiar risk comparison, such as the risk associated with smoking. Two parameters of information processing-efficiency and level-were derived from visual attention. A random sample of participants from the general population (N= 68) interpreted a given risk level with the help of the risk ladder. Numeracy was negatively correlated with overall visual attention on the risk ladder (r(s) =-0.28, p= 0.01), indicating that the lower the numeracy, the more the time spent looking at the whole risk ladder. Numeracy was positively correlated with the efficiency of processing relevant frequency (r(s) = 0.34, p improving risk communication formats. © 2011 Society for Risk Analysis.

  14. Implementability of two-qubit unitary operations over the butterfly network and the ladder network with free classical communication

    Energy Technology Data Exchange (ETDEWEB)

    Akibue, Seiseki [Department of Physics, Graduate School of Science, The University of Tokyo, Tokyo (Japan); Murao, Mio [Department of Physics, Graduate School of Science, The University of Tokyo, Tokyo, Japan and NanoQuine, The University of Tokyo, Tokyo (Japan)

    2014-12-04

    We investigate distributed implementation of two-qubit unitary operations over two primitive networks, the butterfly network and the ladder network, as a first step to apply network coding for quantum computation. By classifying two-qubit unitary operations in terms of the Kraus-Cirac number, the number of non-zero parameters describing the global part of two-qubit unitary operations, we analyze which class of two-qubit unitary operations is implementable over these networks with free classical communication. For the butterfly network, we show that two classes of two-qubit unitary operations, which contain all Clifford, controlled-unitary and matchgate operations, are implementable over the network. For the ladder network, we show that two-qubit unitary operations are implementable over the network if and only if their Kraus-Cirac number do not exceed the number of the bridges of the ladder.

  15. Implementability of two-qubit unitary operations over the butterfly network and the ladder network with free classical communication

    International Nuclear Information System (INIS)

    Akibue, Seiseki; Murao, Mio

    2014-01-01

    We investigate distributed implementation of two-qubit unitary operations over two primitive networks, the butterfly network and the ladder network, as a first step to apply network coding for quantum computation. By classifying two-qubit unitary operations in terms of the Kraus-Cirac number, the number of non-zero parameters describing the global part of two-qubit unitary operations, we analyze which class of two-qubit unitary operations is implementable over these networks with free classical communication. For the butterfly network, we show that two classes of two-qubit unitary operations, which contain all Clifford, controlled-unitary and matchgate operations, are implementable over the network. For the ladder network, we show that two-qubit unitary operations are implementable over the network if and only if their Kraus-Cirac number do not exceed the number of the bridges of the ladder

  16. Acute effects of Resistance exercise performed on ladder on energy metabolism, stress, and muscle damage in rats

    Directory of Open Access Journals (Sweden)

    João Guilherme Oliveira Silvestre

    2017-05-01

    Full Text Available Abstract AIMS To evaluate the acute effects of a resistance exercise session performed on ladder on energy metabolism, stress, and muscle damage in rats. METHODS Male Wistar rats were randomly distributed in Exercise (E (n=30 and Control (C (n = 20 groups. The E group performed a resistance exercise session on a vertical ladder with weights on their tails. Blood samples were collected at rest and after each climb to analyze lactate levels and ten minutes after the last climb to analyze lactate dehydrogenase (LDH, creatine kinase (CK, and corticosterone levels. RESULTS Blood lactate levels remained stable during exercise. Serum corticosterone, blood glucose, LDH and CK levels increased and glycogen content decreased in the E group, when compared to the C group. CONCLUSION These results suggest that resistance exercise performed on ladder is a model of high-intensity exercise. However, the stabilization of lactate during the session suggests that the aerobic metabolism is an important factor during the intervals between climbs.

  17. INFLUENCE OF RIVER BED ELEVATION SURVEY CONFIGURATIONS AND INTERPOLATION METHODS ON THE ACCURACY OF LIDAR DTM-BASED RIVER FLOW SIMULATIONS

    Directory of Open Access Journals (Sweden)

    J. R. Santillan

    2016-09-01

    Full Text Available In this paper, we investigated how survey configuration and the type of interpolation method can affect the accuracy of river flow simulations that utilize LIDAR DTM integrated with interpolated river bed as its main source of topographic information. Aside from determining the accuracy of the individually-generated river bed topographies, we also assessed the overall accuracy of the river flow simulations in terms of maximum flood depth and extent. Four survey configurations consisting of river bed elevation data points arranged as cross-section (XS, zig-zag (ZZ, river banks-centerline (RBCL, and river banks-centerline-zig-zag (RBCLZZ, and two interpolation methods (Inverse Distance-Weighted and Ordinary Kriging were considered. Major results show that the choice of survey configuration, rather than the interpolation method, has significant effect on the accuracy of interpolated river bed surfaces, and subsequently on the accuracy of river flow simulations. The RMSEs of the interpolated surfaces and the model results vary from one configuration to another, and depends on how each configuration evenly collects river bed elevation data points. The large RMSEs for the RBCL configuration and the low RMSEs for the XS configuration confirm that as the data points become evenly spaced and cover more portions of the river, the resulting interpolated surface and the river flow simulation where it was used also become more accurate. The XS configuration with Ordinary Kriging (OK as interpolation method provided the best river bed interpolation and river flow simulation results. The RBCL configuration, regardless of the interpolation algorithm used, resulted to least accurate river bed surfaces and simulation results. Based on the accuracy analysis, the use of XS configuration to collect river bed data points and applying the OK method to interpolate the river bed topography are the best methods to use to produce satisfactory river flow simulation outputs

  18. EVOLUŢIA DE LA COMPUŞII MONO- SPRE POLINUCLEARI ÎN BAZA UNOR LIGANZI MONOXIMICI

    Directory of Open Access Journals (Sweden)

    Eduard COROPCEANU

    2015-12-01

    Full Text Available A fost realizată sinteza unei serii de compuşi coordinativi cu liganzi monoximici, în care s-a urmărit evoluţia de la com-puşii mononucleari spre cei cu structură polimerică. În calitate de liganzi monoximici au fost utilizaţi 2- şi 4-pyridinaldoxime. În calitate de liganzi-punte au fost utilizaţi anionii sulfat, acetat, malonat, succinat, adipat, tereftalat etc. Utilizarea ligan-dului 2-piridinaldoxima creează premise pentru amplasarea acestor molecule în complex în poziţie cis, fapt ce determină formarea lanţurilor polimerice în formă de zig-zag. Specificul fiecărui acid dicarboxilic, capacitatea lui de a coordina influenţează în mod determinant structura moleculară a polimerilor asamblaţi. Datorită capacităţii de a manifesta număr de coordinare mai înalt, deseori ionii de cadmiu oferă posibilitatea asamblării unor arhitecturi polimerice mai complica-te decât cei de zinc.EVOLUTION FROM MONO- TO POLYNUCLEAR COMPOUNDS ON THE BASIS OF SOME MONOXIME LIGANDSThere was performed the synthesis of a series of coordination compounds with monoxime ligands, in which there was observed the evolution from the mononuclear compounds to those with polymer structure. As monoxime ligands there was used 2- and 4-pyridinealdoximes. As bridge-ligands there was used sulfate, acetate, malonate, succinate, adipate, terephthalate anion etc. The use of 2-pyridinealdoxime ligand creates premises for the location of these molecules in complex with cis position, a fact which determines the formation of polymer chains in zig-zag form. The specific of each dicarboxylic acid, its ability to coordinate, decisively influences the molecular structure of the assembled polymers. Due to their ability of manifesting a higher coordination number, cadmium ions often offer the possibility of assembling some polymer architectures more complicated than those of zinc.

  19. Selection of an experimental fish ladder located at the dam of the Itaipu Binacional, Paraná River, Brazil

    Directory of Open Access Journals (Sweden)

    Domingo Rodriguez Fernandez

    2004-08-01

    Full Text Available The specific selection of a weir and orifice type experimental fish ladder in the dam of the Itaipu Reservoir (Paraná River was evaluated by samplings in the river downstream and at two points along the ladder (at heights of 10 m and 27 m during 28 months. Among the 65 species recorded in the river (immediate downstream of the dam, 27 were captured on the ladder. The species that showed highest density on the ladder, the majority migratory, were moderately, or only slightly, abundant downstream. Among the most abundant species downstream, only one, non-migratory, was recorded in the ladder. The structure presented a negative selection in relation to large migratory pimelodids that might be overcome by enlarging the scale of its design. The sampling demonstrated a moderate selection of species along the ladder and its hydraulic model proved satisfactory regarding the attraction and efficient ascent of the fishes.A seleção específica de uma escada de peixes do tipo seqüência de tanques, com passagem de fundo (tipo weir and orifice, na barragem da hidrelétrica de Itaipu (rio Paraná, foi avaliada através de amostragens no rio a jusante (amostragem trimestral em 1997 e em dois pontos ao longo da escada (10 e 27m de altura; nov/94 a jan/97 e nov/94 a fev/97, respectivamente. Das 65 espécies registradas no rio imediatamente a jusante da barragem, 27 foram capturadas na escada. As espécies com maior densidade na escada, em sua maioria migradoras, tiveram abundância moderada ou baixa a jusante. Entre as mais abundantes a jusante, apenas uma, não migradora, foi registrada na escada. A escada apresentou seleção negativa aos grandes pimelodídeos migradores que pode ser superada com a ampliação na escala do projeto. As amostragens evidenciaram baixa seletividade específica ao longo da escada, sendo seu modelo hidráulico satisfatório na atração e eficiente na ascensão de peixes.

  20. A Demonstration of Helping Adolescents with Mild Intellectual Disability Climb Ladders

    Science.gov (United States)

    Chan, Kok Hoe Anthony; Varahan, Jayashree Lakshmi; Loh, Peng Loong Daniel; Tan, Sey Ing

    2011-01-01

    A research team at a vocational school in Singapore, catering mainly to students between the ages of 17-21 with mild intellectual disability, studied how to best address the challenge of enabling students to learn how to climb ladders (a skill necessary at many job placements). They documented the approach used and suggested extrapolations and…

  1. Greenhouse irrigation control system design based on ZigBee and fuzzy PID technology

    Science.gov (United States)

    Zhou, Bing; Yang, Qiliang; Liu, Kenan; Li, Peiqing; Zhang, Jing; Wang, Qijian

    In order to achieve the water demand information accurately detect of the greenhouse crop and its precision irrigation automatic control, this article has designed a set of the irrigated control system based on ZigBee and fuzzy PID technology, which composed by the soil water potential sensor, CC2530F256 wireless microprocessor, IAR Embedded Workbench software development platform. And the time of Irrigation as the output .while the amount of soil water potential and crop growth cycle as the input. The article depended on Greenhouse-grown Jatropha to verify the object, the results show that the system can irrigate timely and appropriately according to the soil water potential and water demend of the different stages of Jatropha growth , which basically meet the design requirements. Therefore, the system has broad application prospects in the amount of greenhouse crop of fine control irrigation.

  2. Topic Order in Introductory Physics and its Impact on the STEM Curricular Ladder

    Directory of Open Access Journals (Sweden)

    Teresa L Larkin

    2017-02-01

    Full Text Available Introductory physics courses are an important rung on the curricular ladder in STEM. These courses help to strengthen students critical thinking and problem solving skills while simultaneously introducing them to many topics they will explore in more detail in later courses in physics and engineering. For these reasons, introductory physics is a required element on the curricular ladder. Most often, introductory physics is offered as a two-semester sequence with basic mechanics being taught in the first semester and electricity and magnetism in the second. In fact, this curricular sequence has not been altered in decades. Is there a reason for this? There are many other enduring questions that arise pertaining to these foundation courses in physics. These questions include: Does taking the introductory course sequence “out of order” have an impact on student learning in physics? What topics should be taught? When should these topics be taught? What topics could be left out? The list of questions is essentially endless. This paper will address some of these questions in part, through a brief discussion on student learning in a second-semester algebra-based physics course. Connections will also be made to the broader curricular ladder in STEM. To this end, an illustration that makes connections to an engineering statics course will be presented. This discussion will conclude by presenting some broader implications for the larger STEM communities.

  3. 29 CFR 1910.29 - Manually propelled mobile ladder stands and scaffolds (towers).

    Science.gov (United States)

    2010-07-01

    ... HEALTH ADMINISTRATION, DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Walking-Working... edges, burrs or other safety hazards. (3) Work levels. (i) The maximum work level height shall not... rigid platforms at each work level. (iv) The steps of ladder stands shall be fabricated from slip...

  4. Essential spectra of difference operators on Zn-periodic graphs

    International Nuclear Information System (INIS)

    Rabinovich, Vladimir S; Roch, Steffen

    2007-01-01

    Let (X, ρ) be a discrete metric space. We suppose that the group Z n acts freely on X and that the number of orbits of X with respect to this action is finite. Then we call X a Z n -periodic discrete metric space. We examine the Fredholm property and essential spectra of band-dominated operators on l p (X) when 1 n and their limit operators. In the case where X is the set of vertices of a combinatorial graph, the graph structure defines a Schroedinger operator on l p (X) in a natural way. We illustrate our approach by determining the essential spectra of Schroedinger operators with slowly oscillating potential both on zig-zag and on hexagonal graphs, the latter being related to nano-structures

  5. Effects of hydrogenation on magnetism of UNiGe

    Energy Technology Data Exchange (ETDEWEB)

    Adamska, A.M., E-mail: anna@mag.mff.cuni.cz [Department of Condensed Matter Physics, Charles University, Ke Karlovu 5, 12116 Prague 2 (Czech Republic); Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30 059 Cracow (Poland); Havela, L. [Department of Condensed Matter Physics, Charles University, Ke Karlovu 5, 12116 Prague 2 (Czech Republic); Prochazka, J. [Faculty of Sports and Physical Education, Charles University, Jose Martiho 31, 16252, Prague 6 (Czech Republic); Andreev, A.V. [Institute of Physics, Academy of Sciences, Na Slovance 2, 18221 Prague (Czech Republic); Skourski, Y. [Dresden High Magnetic Field Laboratory, Helmholtz-Zentrum Dresden-Rossendorf, 01314 Dresden (Germany)

    2011-12-15

    U-based intermetallic compound UNiGe absorbs hydrogen up to the stoichiometry UNiGeH{sub 1.2}. In analogy to other compounds with the TiNiSi-type of structure, the structure is modified into hexagonal. The zig-zag U-chains are stretched, the U-U spacing is largely enhanced and the ordering temperature increases up to 100 K. The ordered state has a spontaneous moment, but it is unlikely to be a simple ferromagnet. - Highlights: > UNiGe exhibits a variety of magnetic properties. > Hydrogenation modifies the crystal, electronic structure, and the magnetic properties. > Upon hydrogenation, the crystal symmetry of UNiGe increases from orthorhombic to hexagonal. > Magnetic ordering temperature of UNiGe (T{sub N}=44 K) is double in the hydride, possible second phase transition.

  6. A contribution to the knowledge of the cetological fauna in the waters of Western Sardinia

    Directory of Open Access Journals (Sweden)

    Alexandre Gannier

    1998-12-01

    Full Text Available Abstract A 10 day survey was carried out off Western Sardinia during summer 1997. Conventional observation methods were used onboard a 12 meter motorsailer. A zig-zag sampling of 584 kilometers and 65 hours of observation were done, during which 21 groups of cetaceans were sighted. Five species were observed: the fin whale (3 sightings, the striped dolphin (10 sightings, the common dolphin (6 sightings, the bottlenose dolphin and the sperm whale (1 sighting each. High sighting frequencies were obtained for the striped dolphin in the pelagic area and for the common dolphin in the slope area, suggesting that each species favours a distinct habitat. This study is in reasonable concordance with the few results already published on the subject. However more research must be done in this area.

  7. Comparison of expandable endotracheal stents in the treatment of surgically induced piglet tracheomalacia.

    Science.gov (United States)

    Mair, E A; Parsons, D S; Lally, K P; Van Dellen, A F

    1991-09-01

    Present surgical alternatives for pediatric tracheobronchomalacia are limited and associated with many potentially undesirable complications. The feasibility of different intraluminal expandable endotracheal stents for the treatment of surgically induced tracheomalacia was analyzed in 27 piglets. A potentially fatal tracheomalacia was surgically created. Either a stainless steel "zig-zag" stent or a woven polymeric stent was then implanted. Tracheal patency, mucosal function, histopathologic respiratory tract changes, and effects of the stent on esophageal motility were evaluated over a 16-week period. Piglets with steel stents uniformly experienced intense inflammation leading to tracheal dysfunction and death. Piglets with polymeric stents experienced minimal respiratory symptoms. Expandable polymeric endotracheal stents alleviate surgically induced piglet tracheomalacia, were easy to insert, allowed for tracheal growth, and reduced the need for high-risk surgical procedures with prolonged ventilatory support.

  8. Electronic properties and mechanical strength of β-phosphorene nano-ribbons

    Energy Technology Data Exchange (ETDEWEB)

    Swaroop, Ram; Bhatia, Pradeep; Kumar, Ashok, E-mail: ashok@cup.ac.in [Centre for Physical Sciences, School of Basic and Applied Sciences, Central University of Punjab, Bathinda, India-151001 (India)

    2016-05-06

    We have performed first principles calculations to find out the effect of mechanical strain on the electronic properties of zig-zag edged nano ribbons of β-phosphorene. It is found that electronic band-gap get opened-up to 2.61 eV by passivation of the edges of ribbons. Similarly, the mechanical strength is found to be increase from 1.75 GPa to 2.65 GPa on going from unpassivated nano ribbons to passivated ones along with the 2% increase in ultimate tensile strain. The band-gap value of passivated ribbon gets decreased to 0.43 eV on applying strain up to which the ribbon does not break. These tunable properties of β-phospherene with passivation with H-atom and applying mechanical strain offer its use in tunable nano electronics.

  9. Dual band multi frequency rectangular patch microstrip antenna with flyswatter shaped slot for wireless systems

    International Nuclear Information System (INIS)

    Bhardwaj, Dheeraj; Saraswat, Shriti; Gulati, Gitansh; Shekhar, Snehanshu; Joshi, Kanika; Sharma, Komal

    2016-01-01

    In this paper a dual band planar antenna has been proposed for IEEE 802.16 Wi-MAX /IEEE 802.11 WLAN/4.9 GHz public safety applications. The antenna comprises a frequency bandwidth of 560MHz (3.37GHz-3.93GHz) for WLAN and WiMAX and 372MHz (4.82GHz-5.192GHz) for 4.9 GHz public safety applications and Radio astronomy services (4.8-4.94 GHz). The proposed antenna constitutes of a single microstrip patch reactively loaded with three identical steps positioned in a zig-zag manner towards the radiating edges of the patch. The coaxially fed patch antenna characteristics (radiation pattern, antenna gain, antenna directivity, current distribution, S_1_1) have been investigated. The antenna design is primarily focused on achieving a dual band operation.

  10. Dual band multi frequency rectangular patch microstrip antenna with flyswatter shaped slot for wireless systems

    Energy Technology Data Exchange (ETDEWEB)

    Bhardwaj, Dheeraj, E-mail: dbhardwaj.bit@gmail.com [Department of Physics, BIT-Mesra-Jaipur Campus, Jaipur 302017 (India); Saraswat, Shriti, E-mail: saraswat.srishti@gmail.com; Gulati, Gitansh, E-mail: gitanshgulati@gmail.com; Shekhar, Snehanshu, E-mail: snehanshushekhar.bit@gmail.com; Joshi, Kanika, E-mail: kanika.karesh@gmail.com [Department of Electronics & Communication, BIT-Mesra-Jaipur Campus, Jaipur 302017 (India); Sharma, Komal, E-mail: kbhardwaj18@gmail.com [Department of Physics, Swami Keshvanand Institute of Technology, Jaipur 302017 (India)

    2016-03-09

    In this paper a dual band planar antenna has been proposed for IEEE 802.16 Wi-MAX /IEEE 802.11 WLAN/4.9 GHz public safety applications. The antenna comprises a frequency bandwidth of 560MHz (3.37GHz-3.93GHz) for WLAN and WiMAX and 372MHz (4.82GHz-5.192GHz) for 4.9 GHz public safety applications and Radio astronomy services (4.8-4.94 GHz). The proposed antenna constitutes of a single microstrip patch reactively loaded with three identical steps positioned in a zig-zag manner towards the radiating edges of the patch. The coaxially fed patch antenna characteristics (radiation pattern, antenna gain, antenna directivity, current distribution, S{sub 11}) have been investigated. The antenna design is primarily focused on achieving a dual band operation.

  11. Dual band multi frequency rectangular patch microstrip antenna with flyswatter shaped slot for wireless systems

    Science.gov (United States)

    Bhardwaj, Dheeraj; Saraswat, Shriti; Gulati, Gitansh; Shekhar, Snehanshu; Joshi, Kanika; Sharma, Komal

    2016-03-01

    In this paper a dual band planar antenna has been proposed for IEEE 802.16 Wi-MAX /IEEE 802.11 WLAN/4.9 GHz public safety applications. The antenna comprises a frequency bandwidth of 560MHz (3.37GHz-3.93GHz) for WLAN and WiMAX and 372MHz (4.82GHz-5.192GHz) for 4.9 GHz public safety applications and Radio astronomy services (4.8-4.94 GHz). The proposed antenna constitutes of a single microstrip patch reactively loaded with three identical steps positioned in a zig-zag manner towards the radiating edges of the patch. The coaxially fed patch antenna characteristics (radiation pattern, antenna gain, antenna directivity, current distribution, S11) have been investigated. The antenna design is primarily focused on achieving a dual band operation.

  12. Establishing analogies between the physics of extra dimensions and carbon nanotubes

    International Nuclear Information System (INIS)

    Woul, Jonas de; Merle, Alexander; Ohlsson, Tommy

    2012-01-01

    We point out a conceptual analogy between the physics of extra spatial dimensions and the physics of carbon nanotubes which arises for principle reasons, although the corresponding energy scales are at least ten orders of magnitude apart. For low energies, one can apply the Kaluza-Klein description to both types of systems, leading to two completely different but consistent interpretations of the underlying physics. In particular, we discuss in detail the Kaluza-Klein description of armchair and zig-zag carbon nanotubes. Furthermore, we describe how certain experimental results for carbon nanotubes could be re-interpreted in terms of the Kaluza-Klein description. Finally, we present ideas for new measurements that could allow to probe concepts of models with extra spatial dimensions in table-top experiments, providing further links between condensed matter and particle physics.

  13. A low power 2.4 GHz transceiver for ZigBee applications

    International Nuclear Information System (INIS)

    Liu Weiyang; Chen Jingjing; Wang Haiyong; Wu Nanjian

    2013-01-01

    This paper presents a low power 2.4 GHz transceiver for ZigBee applications. This transceiver adopts low power system architecture with a low-IF receiver and a direct-conversion transmitter. The receiver consists of a new low noise amplifier (LNA) with a noise cancellation function, a new inverter-based variable gain complex filter (VGCF) for image rejection, a passive quadrature mixer, and a decibel linear programmable gain amplifier (PGA). The transmitter adopts a quadrature mixer and a class-B mode variable gain power amplifier (PA) to reduce power consumption. This transceiver is implemented in 0.18 μm CMOS technology. The receiver achieves −95 dBm of sensitivity, 28 dBc of image rejection, and −8 dBm of third-order input intercept point (IIP3). The transmitter can deliver a maximum of +3 dBm output power with PA efficiency of 30%. The whole chip area is less than 4.32 mm 2 . It only consumes 12.63 mW in receiving mode and 14.22 mW in transmitting mode, respectively. (semiconductor integrated circuits)

  14. Key role of orbital anisotropy in geometrically frustrated electron system

    International Nuclear Information System (INIS)

    Onishi, Hiroaki; Hotta, Takashi

    2005-01-01

    By using the density matrix renormalization group method, we investigate ground- and excited-state properties of the e g -orbital degenerate Hubbard model at quarter filling for two kinds of lattices, zigzag chain and ladder. In the zigzag chain, the system is effectively regarded as a decoupled double chain of the S=12 antiferromagnetic Heisenberg model, and the spin gap is approximately zero, similar to the case of weakly coupled Heisenberg chains. On the other hand, in the ladder, the spin correlation on the rung remains robust and the spin gap exists

  15. Clarifying the Hubble constant tension with a Bayesian hierarchical model of the local distance ladder

    Science.gov (United States)

    Feeney, Stephen M.; Mortlock, Daniel J.; Dalmasso, Niccolò

    2018-05-01

    Estimates of the Hubble constant, H0, from the local distance ladder and from the cosmic microwave background (CMB) are discrepant at the ˜3σ level, indicating a potential issue with the standard Λ cold dark matter (ΛCDM) cosmology. A probabilistic (i.e. Bayesian) interpretation of this tension requires a model comparison calculation, which in turn depends strongly on the tails of the H0 likelihoods. Evaluating the tails of the local H0 likelihood requires the use of non-Gaussian distributions to faithfully represent anchor likelihoods and outliers, and simultaneous fitting of the complete distance-ladder data set to ensure correct uncertainty propagation. We have hence developed a Bayesian hierarchical model of the full distance ladder that does not rely on Gaussian distributions and allows outliers to be modelled without arbitrary data cuts. Marginalizing over the full ˜3000-parameter joint posterior distribution, we find H0 = (72.72 ± 1.67) km s-1 Mpc-1 when applied to the outlier-cleaned Riess et al. data, and (73.15 ± 1.78) km s-1 Mpc-1 with supernova outliers reintroduced (the pre-cut Cepheid data set is not available). Using our precise evaluation of the tails of the H0 likelihood, we apply Bayesian model comparison to assess the evidence for deviation from ΛCDM given the distance-ladder and CMB data. The odds against ΛCDM are at worst ˜10:1 when considering the Planck 2015 XIII data, regardless of outlier treatment, considerably less dramatic than naïvely implied by the 2.8σ discrepancy. These odds become ˜60:1 when an approximation to the more-discrepant Planck Intermediate XLVI likelihood is included.

  16. Polyembryony and identification of Volkamerian lemon zygotic and nucellar seedlings using RAPD Poliembrionia e identificação de seedlings zigóticos e nucelares de limão volkameriano com RAPD

    Directory of Open Access Journals (Sweden)

    María Andrade-Rodríguez

    2004-06-01

    Full Text Available The objectives of this work were to evaluate the frequency of polyembryony, and to identify zygotic and nucellar seedlings of Citrus volkameriana using RAPD. Twenty-five polyembryonic and eight monoembryonic seeds were cultivated in vitrofor six months. DNA from seedlings was extracted and used in combination with five RAPD primers to identify zygotic or nucellar origin of the seedlings. Environmental conditions of the year affected significantly (POs objetivos deste trabalho foram avaliar a freqüência da poliembrionia e indentificar os seedlings zigóticos e nucelares de Citrus volkameriana usando RAPD. Cultivaram-se in vitro 25 sementes poliembriônicas e 8 monoembriônicas, por seis meses. Extraiu-se o DNA dos seedlings e usou-se em combinação com cinco primers RAPD para identificar a origem zigótica e nucelar das plântulas. Os resultados mostraram que as condições ambientais do ano afetaram significativamente (P<0,05 as características morfológicas dos frutos e o número de embriões por semente. Os índices de sementes poliembriônicas variaram nos três anos de avaliação (30,9%, 44,8% e 54,4%. As características morfológicas não se correlacionaram com a poliembrionia. A cultura in vitro possibilita que todos os embriões de cada semente cresçam, favorecendo os seedlings identificados como zigóticos. Nas sementes poliembriônicas e monoembriônicas, 25,9% e 87,5% dos seedlings, respectivamente, originaram-se sexualmente. Nem todos os seedlings zigóticos foram produzidos por embriões localizados no micrófilo das sementes poliembriônicas.

  17. [Ladder step strategy for surgical repair of congenital concealed penis in children].

    Science.gov (United States)

    Wang, Fu-Ran; Zhong, Hong-Ji; Chen, Yi; Zhao, Jun-Feng; Li, Yan

    2016-11-01

    To assess the feasibility of the ladder step strategy in surgical repair of congenital concealed penis in children. This study included 52 children with congenital concealed penis treated in the past two years by surgical repair using the ladder step strategy, which consists of five main steps: cutting the narrow ring of the foreskin, degloving the penile skin, fixing the penile skin at the base, covering the penile shaft, and reshaping the prepuce. The perioperative data of the patients were prospectively collected and statistically described. Of the 52 patients, 20 needed remodeling of the frenulum and 27 received longitudinal incision in the penoscrotal junction to expose and deglove the penile shaft. The advanced scrotal flap technique was applied in 8 children to cover the penile shaft without tension, the pedicled foreskin flap technique employed in 11 to repair the penile skin defect, and excision of the webbed skin of the ventral penis performed in another 44 to remodel the penoscrotal angle. The operation time, blood loss, and postoperative hospital stay were 40-100 minutes, 5-30 ml, and 3-6 days, respectively. Wound bleeding and infection occurred in 1 and 5 cases, respectively. Follow-up examinations at 3 and 6 months after surgery showed that all the children had a satisfactory penile appearance except for some minor complications (2 cases of penile retraction, 2 cases of redundant ventral skin, and 1 case of iatrogenic penile curvature). The ladder step strategy for surgical repair of congenital concealed penis in children is a simple procedure with minor injury and satisfactory appearance of the penis.

  18. Strongly correlated electrons on two coupled chains

    International Nuclear Information System (INIS)

    Weihong, Z.; Oitmaa, J.; Hamer, C.J.

    2000-01-01

    Full text: The discovery of materials containing S = 1/2 ions which form a 2-leg ladder structure has led to much current research on ladder systems. Pure spin ladders show an unexpected difference between odd-legged ladders (including the single chain) which are gapless with long-range correlations and even-legged ladders which have a spin gap and short range correlations. Even more interesting behaviour occurs when these systems are doped, creating a system of strongly correlated mobile holes, as in the cuprate superconductors. The simplest models in this context are the Hubbard model and the t-J model. Considerable work has been reported on both of these models, using both numerical calculations and approximate analytic theories. We have used series expansion methods to study both of these systems. Our results, in some cases, confirm those of other approaches. In other cases we are able to probe regions of the phase diagram inaccessible to other methods, or to obtain results of increased precision. In this paper we focus on:- 1. The energy and dispersion relation of 1-hole states. 2.The existence of a 2-hole bound state and its energy and dispersion. 3. Spin and charge gaps and the question of phase separation

  19. Hydroxyl-substituted ladder polyethers via selective tandem epoxidation/cyclization sequence.

    Science.gov (United States)

    Czabaniuk, Lara C; Jamison, Timothy F

    2015-02-20

    A new and highly selective method for the synthesis of hydroxyl-substituted tetrahydropyrans is described. This method utilizes titanium(IV) isopropoxide and diethyl tartrate to perform a diastereoselective epoxidation followed by in situ epoxide activation and highly selective endo-cyclization to form the desired tetrahydropyran ring. The HIJ ring fragment of the marine ladder polyether yessotoxin was synthesized using this two-stage tactic that proceeds with high efficiency and excellent regioselectivity.

  20. Indirect effects of impoundment on migrating fish: temperature gradients in fish ladders slow dam passage by adult Chinook salmon and steelhead.

    Directory of Open Access Journals (Sweden)

    Christopher C Caudill

    Full Text Available Thermal layering in reservoirs upstream from hydroelectric dams can create temperature gradients in fishways used by upstream migrating adults. In the Snake River, Washington, federally-protected adult salmonids (Oncorhynchus spp. often encounter relatively cool water in dam tailraces and lower ladder sections and warmer water in the upstream portions of ladders. Using radiotelemetry, we examined relationships between fish passage behavior and the temperature difference between the top and bottom of ladders (∆T at four dams over four years. Some spring Chinook salmon (O. tshawytscha experienced ∆T ≥ 0.5 °C. Many summer and fall Chinook salmon and summer steelhead (O. mykiss experienced ∆T ≥ 1.0 °C, and some individuals encountered ΔT > 4.0°C. As ΔT increased, migrants were consistently more likely to move down fish ladders and exit into dam tailraces, resulting in upstream passage delays that ranged from hours to days. Fish body temperatures equilibrated to ladder temperatures and often exceeded 20°C, indicating potential negative physiological and fitness effects. Collectively, the results suggest that gradients in fishway water temperatures present a migration obstacle to many anadromous migrants. Unfavorable temperature gradients may be common at reservoir-fed fish passage facilities, especially those with seasonal thermal layering or stratification. Understanding and managing thermal heterogeneity at such sites may be important for ensuring efficient upstream passage and minimizing stress for migratory, temperature-sensitive species.

  1. Measuring subjective meaning structures by the laddering method: Theoretical considerations and methodological problems

    DEFF Research Database (Denmark)

    Grunert, Klaus G.; Grunert, Suzanne C.

    1995-01-01

    Starting from a general model of measuring cognitive structures for predicting consumer behaviour, we discuss laddering as a possible method to obtain estimates of consumption-relevant cognitive structures which will have predictive validity. Four criteria for valid measurement are derived and ap...

  2. 基于ZigBee的风电机组远程监测系统设计与实现%The Design and Realization of Remote Monitoring System on Wind Turbine Based on ZigBee

    Institute of Scientific and Technical Information of China (English)

    邬春明; 刘海维

    2014-01-01

    The currently technology of turbine monitoring system mainly uses cable or manual,which not only waste large money,but also waste a lot of man-power. And it can not monitor the operation status of equipments in real time and efficiently. In order to solve the disadvantages of the wind turbine,proposing a remote monitor system for wind turbine which bases on ZigBee. The system consists of collection nodes,network coordination node,as well as the monitoring center node. CC2530 as the processor,which controls sensors to acquire wind operating parameters, and meeting at coordinating node,and sending to monitoring center by 3 G network. The monitor system has a real time,stable,and a certain prospect.%现有的风电机组监控系统主要采用有线或人工巡检的方式,不仅耗费了大量的财物和人力,并且不能实时地、高效地监控设备运行状态。为了解决风电机组监控系统中存在的弊端,提出了基于ZigBee的风电机组远程监控系统。系统由传感器采集节点、网络协调节点,以及监控中心节点组成。采用CC2530处理器,控制传感器采集风电机组运行状态参数,在协调节点汇聚,通过3G网络传到远程监控中心。该系统具有实时性强,稳定性好,具有一定的推广前景。

  3. Ground states, magnetization plateaus and bipartite entanglement of frustrated spin-1/2 Ising-Heisenberg and Heisenberg triangular tubes

    International Nuclear Information System (INIS)

    Alécio, Raphael C.; Lyra, Marcelo L.; Strečka, Jozef

    2016-01-01

    The ground-state phase diagram, magnetization process and bipartite entanglement of the frustrated spin-1/2 Ising-Heisenberg and Heisenberg triangular tube (three-leg ladder) are investigated in a non-zero external magnetic field. The exact ground-state phase diagram of the spin-1/2 Ising-Heisenberg tube with Heisenberg intra-rung and Ising inter-rung couplings consists of six distinct gapped phases, which manifest themselves in a magnetization curve as intermediate plateaus at zero, one-third and two-thirds of the saturation magnetization. Four out of six available ground states exhibit quantum entanglement between two spins from the same triangular unit evidenced by a non-zero concurrence. Density-matrix renormalization group calculations are used in order to construct the ground-state phase diagram of the analogous but purely quantum spin-1/2 Heisenberg tube with Heisenberg intra- and inter-rung couplings, which consists of four gapped and three gapless phases. The Heisenberg tube shows a continuous change of the magnetization instead of a plateau at zero magnetization, while the intermediate one-third and two-thirds plateaus may be present or not in the zero-temperature magnetization curve. - Highlights: • Ground-state properties of Ising-Heisenberg and full Heisenberg spin tubes are studied. • Phases with 1/3 and 2/3 magnetization plateaus are present in both models. • We unveil the region in the parameter space on which inter-rung quantum fluctuations are relevant. • The full Heisenberg tube exhibits quantum bipartite entanglement between intra- as well as inter-rung spins.

  4. Quark-gluon vertex dressing and meson masses beyond ladder-rainbow truncation

    International Nuclear Information System (INIS)

    Matevosyan, Hrayr H.; Thomas, Anthony W.; Tandy, Peter C.

    2007-01-01

    We include a generalized infinite class of quark-gluon vertex dressing diagrams in a study of how dynamics beyond the ladder-rainbow truncation influences the Bethe-Salpeter description of light-quark pseudoscalar and vector mesons. The diagrammatic specification of the vertex is mapped into a corresponding specification of the Bethe-Salpeter kernel, which preserves chiral symmetry. This study adopts the algebraic format afforded by the simple interaction kernel used in previous work on this topic. The new feature of the present work is that in every diagram summed for the vertex and the corresponding Bethe-Salpeter kernel, each quark-gluon vertex is required to be the self-consistent vertex solution. We also adopt from previous work the effective accounting for the role of the explicitly non-Abelian three-gluon coupling in a global manner through one parameter determined from recent lattice-QCD data for the vertex. Within the current model, the more consistent dressed vertex limits the ladder-rainbow truncation error for vector mesons to be never more than 10% as the current quark mass is varied from the u/d region to the b region

  5. Non-local electron transport through normal and topological ladder-like atomic systems

    Science.gov (United States)

    Kurzyna, Marcin; Kwapiński, Tomasz

    2018-05-01

    We propose a locally protected ladder-like atomic system (nanoconductor) on a substrate that is insensitive to external perturbations. The system corresponds to coupled atomic chains fabricated on different surfaces. Electron transport properties of such conductors are studied theoretically using the model tight-binding Su-Schriffer-Hegger (SSH) Hamiltonian and Green's function formalism. We have found that the conductance of the system is almost insensitive to single adatoms and oscillates as a function of the side chain length with very large periods. Non-local character of the electron transport was observed also for topological SSH chains where nontrivial end states survive in the presence of disturbances as well as for different substrates. We have found that the careful inspection of the density of states or charge waves can provide the information about the atom energy levels and hopping amplitudes. Moreover, the ladder-like geometry allows one to distinguish between normal and topological zero-energy states. It is important that topological chains do not reveal Friedel oscillations which are observed in non-topological chains.

  6. Telecast of Astronauts Armstrong and Aldrin by the Lunar Module ladder

    Science.gov (United States)

    1969-01-01

    Astronauts Neil A. Armstrong (on left), commander; and Edwin E. Aldrin Jr., lunar module pilot, are seen standing by the Lunar Module ladder in this black and white reproduction taken from a telecast by the Apollo 11 lunar surface television camera during the Apollo 11 extravehicular activity. This picture was made from a televised image received at the Deep Space Network tracking station at Goldstone, California.

  7. Two-loop ladder diagram contributions to Bhabha scattering. III

    International Nuclear Information System (INIS)

    Bjoerkevoll, K.S.; Osland, P.; Faeldt, G.

    1992-01-01

    The authors evaluate, in the high-energy limit, the sum of the Feynman amplitudes corresponding the six two-loop ladder-like diagrams in Bhabha scattering. This is the limit where s→∞, while t, the electron mass m and the photon mass λ are all being held fixed. In this limit the sum of the six Feynman amplitudes does not depend on the electron mass. When specialized to the region s>>t>>m 2 >>λ 2 , this result complements the one previously obtained. The connection with Φ 3 theory is also investigated. 6 refs

  8. Star-shaped ladder-type ter(p-phenylene)s for efficient multiphoton absorption.

    Science.gov (United States)

    Guo, Lei; Li, King Fai; Wong, Man Shing; Cheah, Kok Wai

    2013-05-04

    Star-shaped ladder-type ter(p-phenylene)s exhibit remarkably efficient multiphoton absorption properties with 2PA cross-section up to 2579 GM at 700 nm and 3PA cross-section up to 3.35 × 10(-76) cm(6) s(2) in the femtosecond regime for a blue-emissive molecule despite having such a short π-conjugated framework.

  9. Quasiparticle dynamics and spin-orbital texture of the SrTiO3 two-dimensional electron gas.

    Science.gov (United States)

    King, P D C; McKeown Walker, S; Tamai, A; de la Torre, A; Eknapakul, T; Buaphet, P; Mo, S-K; Meevasana, W; Bahramy, M S; Baumberger, F

    2014-02-27

    Two-dimensional electron gases (2DEGs) in SrTiO3 have become model systems for engineering emergent behaviour in complex transition metal oxides. Understanding the collective interactions that enable this, however, has thus far proved elusive. Here we demonstrate that angle-resolved photoemission can directly image the quasiparticle dynamics of the d-electron subband ladder of this complex-oxide 2DEG. Combined with realistic tight-binding supercell calculations, we uncover how quantum confinement and inversion symmetry breaking collectively tune the delicate interplay of charge, spin, orbital and lattice degrees of freedom in this system. We reveal how they lead to pronounced orbital ordering, mediate an orbitally enhanced Rashba splitting with complex subband-dependent spin-orbital textures and markedly change the character of electron-phonon coupling, co-operatively shaping the low-energy electronic structure of the 2DEG. Our results allow for a unified understanding of spectroscopic and transport measurements across different classes of SrTiO3-based 2DEGs, and yield new microscopic insights on their functional properties.

  10. Control of Porosity in Ladder Polymers by Solvent-induced Aggregation

    Science.gov (United States)

    Brady, Michael; Gamo, Eri; Wang, Cheng; Xia, Yan

    Porous polymers hold promise as materials for gas absorption, membranes, and organic electronics. In all of these applications, attaining in-plane ordering of backbones and thus porous free volume impacts the ability to adsorb gas, selectively filter molecules, and conduct charges. In this work, hard and soft x-ray scattering and soft x-ray spectroscopy are of focus to study the pore structure, induced by the solution-driven aggregation of ladder polymer thin films made of LP-1 and LP-2. Using GISAXS and AFM it is shown that thermal annealing drives the growth of crystallites in thin films. Due to the completely sp2nature of the ladder polymer backbones, it is expected that backbones are extremely stiff and thus preventing them from packing once left in a metastable state following casting. Therefore, the combination of GIWAXS and GISAXS will be shown to be critical in correctly understanding how pores develop in this 700 m2/g sorbent (N2). Finally, application in CO2/N2 separation membranes towards carbon sequestration will be presented that show gas selectivity is achieved through heteroatom incorporation and polymer blending. In this talk, focus will be placed on state-of-the-art x-ray scattering and spectroscopy, highlighting the importance of chemically sensitive structural information enabled by the combination of spectroscopy and scattering at play with the use of resonant soft x-rays.

  11. Differential expression and processing of transforming growth factor beta induced protein (TGFBIp) in the normal human cornea during postnatal development and aging

    DEFF Research Database (Denmark)

    Karring, Henrik; Runager, Kasper; Valnickova, Zuzana

    2010-01-01

    Transforming growth factor beta induced protein (TGFBIp, also named keratoepithelin) is an extracellular matrix protein abundant in the cornea. The purpose of this study was to determine the expression and processing of TGFBIp in the normal human cornea during postnatal development and aging...... trimming events from the N-terminus of mature TGFBIp generate TGFBIp isoforms which form a similar "zig-zag" pattern when separated by 2-D polyacrylamide gel electrophoresis (PAGE). This study shows that in humans TGFBIp is more abundant in mature corneas than in the developing cornea...... and that the processing of TGFBIp changes during postnatal development of the cornea. In addition, TGFBIp appears to be degraded in a highly orchestrated manner in the normal human cornea with the resulting C-terminal fragments being retained in the cornea. The age-related changes in the expression and processing...

  12. Graphite edge controlled registration of monolayer MoS{sub 2} crystal orientation

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Chun-I; Butler, Christopher John; Yang, Hung-Hsiang; Chu, Yu-Hsun; Luo, Chi-Hung; Sun, Yung-Che; Hsu, Shih-Hao; Yang, Kui-Hong Ou [Department of Physics, National Taiwan University, Taipei 10617, Taiwan (China); Huang, Jing-Kai; Hsing, Cheng-Rong; Wei, Ching-Ming, E-mail: cmw@phys.sinica.edu.tw; Li, Lain-Jong, E-mail: lanceli@gate.sinica.edu.tw [Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan (China); Lin, Minn-Tsong, E-mail: mtlin@phys.ntu.edu.tw [Department of Physics, National Taiwan University, Taipei 10617, Taiwan (China); Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan (China)

    2015-05-04

    Transition metal dichalcogenides such as the semiconductor MoS{sub 2} are a class of two-dimensional crystals. The surface morphology and quality of MoS{sub 2} grown by chemical vapor deposition are examined using atomic force and scanning tunneling microscopy techniques. By analyzing the moiré patterns from several triangular MoS{sub 2} islands, we find that there exist at least five different superstructures and that the relative rotational angles between the MoS{sub 2} adlayer and graphite substrate lattices are typically less than 3°. We conclude that since MoS{sub 2} grows at graphite step-edges, it is the edge structure which controls the orientation of the islands, with those growing from zig-zag (or armchair) edges tending to orient with one lattice vector parallel (perpendicular) to the step-edge.

  13. Assessment of Theories for Free Vibration Analysis of Homogeneous and Multilayered Plates

    Directory of Open Access Journals (Sweden)

    Erasmo Carrera

    2004-01-01

    Full Text Available This paper assesses classical and advanced theories for free vibrational response of homogeneous and multilayered simply supported plates. Closed form solutions are given for thick and thin geometries. Single layer and multilayered plates made of metallic, composite and piezo-electric materials, are considered. Classical theories based on Kirchhoff and Reissner-Mindlin assumptions are compared with refined theories obtained by enhancing the order of the expansion of the displacement fields in the thickness direction z. The effect of the Zig-Zag form of the displacement distribution in z as well as of the Interlaminar Continuity of transverse shear and normal stresses at the layer interface were evaluated. A number of conclusions have been drawn. These conclusions could be used as desk-bed in order to choose the most valuable theories for a given problem.

  14. THE EFFECT OF PLAYING SNAKE AND LADDER TOWARD THE RESULT STUDY OF ARITHMETIC ADDITION FOR STUDENT WITH MENTALLY RETARDED STUDENT

    Directory of Open Access Journals (Sweden)

    Arianti Iman Sari

    2016-12-01

    Full Text Available The purpose of this research were to describe: (1 the study result of arithmetic addition operation for fourth grade student with mentally retarded in SDLB before playing the Snake and Ladder activity (2 the study result of arithmetic addition operation for fourth grade student with mentally retarded in SDLB after playing the Snake and Ladder activity (3 the effect of Snake and Ladder playing toward the result study of arithmetic addition for fourth grade student with mentally retarded SDLB. This research used SSR (Single Subject Research with A-B-A design. Collecting the data was done by using assessment instrument, tests and observations. The result of this research showed that playing Snake and Ladder affected the study result of arithmetic addition operation for fourth-grade children with mentally retarded student in SDLB. Tujuan penelitian ini adalah mendeskripsikan (1 Hasil belajar penjumlahan siswa kelas 4 SDLB sebelum melakukan kegiatan bermain Ular Tangga (2 Hasil belajar penjumlahan siswa kelas 4 SDLB sesudah melakukan kegiatan bermain Ular Tangga (3 Pengaruh bermain Ular Tangga terhadap hasil belajar penjumlahan siswa kelas 4 SDLB. Penelitian ini menggunakan rancangan penelitian SSR (Single Subject Research dengan desain A-B-A. Pengumpulan data menggunakan instrumen assesmen, tes dan observasi. Hasil penelitian menunjukkan bermain ular tangga berpengaruh terhadap hasil belajar penjumlahan siswa tunagrahita kelas 4 SDLB.

  15. Energy-efficient hydrogen separation by AB-type ladder-polymer molecular sieves

    KAUST Repository

    Ghanem, Bader

    2014-07-19

    The synthesis, microstructures, and exceptional gas transport properties of two new soluble ladder polymers, polymers of intrinsic microporosity (TPIM-1 and TPIM-2) containing triptycene moieties substituted with branched isopropyl and linear propyl chains at the 9,10-bridgeheads were reported. The precursor A-B monomers were modified with an o -difluoride functionality for enhanced activation for nucleophilic aromatic substitution. In a Schlenk tube, a mixture of the A-B monomer, 18-crown-6, anhydrous DMF and anhydrous potassium carbonate was stirred at 155 °C under nitrogen atmosphere for 20 min followed by the addition of toluene. The reaction was continued for another 45 min and more toluene was added. After another 45 min the reaction mixture was cooled to room temperature and poured into methanol. Slow evaporation of filtered, dilute 3-5 wt% chloroform solutions from a leveled glass plate yielded isotropic polymer films. Dry membranes were soaked in methanol for 24 h, air-dried, and then heated at 120°C for 24 h under high vacuum to remove any traces of residual solvent. TPIM-1 exhibits simultaneous boosts in permeability and selectivity, which highlights the significant potential of an isopropyl-substituted triptycene moiety as a contortion center for ladder PIMs.

  16. Energy-efficient hydrogen separation by AB-type ladder-polymer molecular sieves

    KAUST Repository

    Ghanem, Bader; Swaidan, Raja; Ma, Xiaohua; Litwiller, Eric; Pinnau, Ingo

    2014-01-01

    The synthesis, microstructures, and exceptional gas transport properties of two new soluble ladder polymers, polymers of intrinsic microporosity (TPIM-1 and TPIM-2) containing triptycene moieties substituted with branched isopropyl and linear propyl chains at the 9,10-bridgeheads were reported. The precursor A-B monomers were modified with an o -difluoride functionality for enhanced activation for nucleophilic aromatic substitution. In a Schlenk tube, a mixture of the A-B monomer, 18-crown-6, anhydrous DMF and anhydrous potassium carbonate was stirred at 155 °C under nitrogen atmosphere for 20 min followed by the addition of toluene. The reaction was continued for another 45 min and more toluene was added. After another 45 min the reaction mixture was cooled to room temperature and poured into methanol. Slow evaporation of filtered, dilute 3-5 wt% chloroform solutions from a leveled glass plate yielded isotropic polymer films. Dry membranes were soaked in methanol for 24 h, air-dried, and then heated at 120°C for 24 h under high vacuum to remove any traces of residual solvent. TPIM-1 exhibits simultaneous boosts in permeability and selectivity, which highlights the significant potential of an isopropyl-substituted triptycene moiety as a contortion center for ladder PIMs.

  17. 4-bit digital to analog converter using R-2R ladder and binary weighted resistors

    Science.gov (United States)

    Diosanto, J.; Batac, M. L.; Pereda, K. J.; Caldo, R.

    2017-06-01

    The use of a 4-bit digital-to-analog converter using two methods; Binary Weighted Resistors and R-2R Ladder is designed and presented in this paper. The main components that were used in constructing both circuits were different resistor values, operational amplifier (LM741) and single pole double throw switches. Both circuits were designed using MULTISIM software to be able to test the circuit for its ideal application and FRITZING software for the layout designing and fabrication to the printed circuit board. The implementation of both systems in an actual circuit benefits in determining and comparing the advantages and disadvantages of each. It was realized that the binary weighted circuit is more efficient DAC, having lower percentage error of 0.267% compared to R-2R ladder circuit which has a minimum of percentage error of 4.16%.

  18. Thermoelectric Properties of Solution-Processed n-Doped Ladder-Type Conducting Polymers

    DEFF Research Database (Denmark)

    Wang, Suhao; Sun, Hengda; Ail, Ujwala

    2016-01-01

    Ladder-type "torsion-free" conducting polymers (e.g., polybenzimidazobenzophenanthroline (BBL)) can outperform "structurally distorted" donor-acceptor polymers (e.g., P(NDI2OD-T2)), in terms of conductivity and thermoelectric power factor. The polaron delocalization length is larger in BBL than...... in P(NDI2OD-T2), resulting in a higher measured polaron mobility. Structure-function relationships are drawn, setting material-design guidelines for the next generation of conducting thermoelectric polymers....

  19. Development of a 325 MHz ladder-RFQ of the 4-rod-type

    Energy Technology Data Exchange (ETDEWEB)

    Schuett, Maximilian; Ratzinger, Ulrich [Institut fuer Angewandte Physik, Goethe-Universitaet, Frankfurt a. M. (Germany); Brodhage, Robert [GSI, Darmstadt (Germany)

    2015-07-01

    For the research program with cooled antiprotons at FAIR a dedicated 70 MeV, 70 mA proton injector is required. In the low energy section, between the Ion Source and the main linac an RFQ will be used. The 325 MHz RFQ will accelerate protons from 95 keV to 3.0 MeV. This particular high frequency for an RFQ creates difficulties, which are challenging in developing this cavity. In order to define a satisfactory geometrical configuration for this resonator, both from the RF and the mechanical point of view, different designs have been examined and compared. Very promising results have been reached with a ladder type RFQ, which has been investigated since 2013. We present recent 3D simulations of the general layout and of a complete cavity demonstrating the power of a ladder type RFQ as well as measurements of a 0.8 m prototype RFQ, which was manufactured in late 2014 and designed for RF power and vacuum tests. We outline a possible RF layout for the RFQ within the new FAIR proton injector and highlight the mechanical advantages.

  20. Magnon localization and Bloch oscillations in finite Heisenberg spin chains in an inhomogeneous magnetic field.

    Science.gov (United States)

    Kosevich, Yuriy A; Gann, Vladimir V

    2013-06-19

    We study the localization of magnon states in finite defect-free Heisenberg spin-1/2 ferromagnetic chains placed in an inhomogeneous magnetic field with a constant spatial gradient. Continuous transformation from the extended magnon states to the localized Wannier-Zeeman states in a finite spin chain placed in an inhomogeneous field is described both analytically and numerically. We describe for the first time the non-monotonic dependence of the energy levels of magnons, both long and short wavelength, on the magnetic field gradient, which is a consequence of magnon localization in a finite spin chain. We show that, in contrast to the destruction of the magnon band and the establishment of the Wannier-Stark ladder in a vanishingly small field gradient in an infinite chain, the localization of magnon states at the chain ends preserves the memory of the magnon band. Essentially, the localization at the lower- or higher-field chain end resembles the localization of the positive- or negative-effective-mass band quasiparticles. We also show how the beat dynamics of coherent superposition of extended spin waves in a finite chain in a homogeneous or weakly inhomogeneous field transforms into magnon Bloch oscillations of the superposition of localized Wannier-Zeeman states in a strongly inhomogeneous field. We provide a semiclassical description of the magnon Bloch oscillations and show that the correspondence between the quantum and semiclassical descriptions is most accurate for Bloch oscillations of the magnon coherent states, which are built from a coherent superposition of a large number of the nearest-neighbour Wannier-Zeeman states.

  1. Magnon localization and Bloch oscillations in finite Heisenberg spin chains in an inhomogeneous magnetic field

    International Nuclear Information System (INIS)

    Kosevich, Yuriy A; Gann, Vladimir V

    2013-01-01

    We study the localization of magnon states in finite defect-free Heisenberg spin-1/2 ferromagnetic chains placed in an inhomogeneous magnetic field with a constant spatial gradient. Continuous transformation from the extended magnon states to the localized Wannier–Zeeman states in a finite spin chain placed in an inhomogeneous field is described both analytically and numerically. We describe for the first time the non-monotonic dependence of the energy levels of magnons, both long and short wavelength, on the magnetic field gradient, which is a consequence of magnon localization in a finite spin chain. We show that, in contrast to the destruction of the magnon band and the establishment of the Wannier–Stark ladder in a vanishingly small field gradient in an infinite chain, the localization of magnon states at the chain ends preserves the memory of the magnon band. Essentially, the localization at the lower- or higher-field chain end resembles the localization of the positive- or negative-effective-mass band quasiparticles. We also show how the beat dynamics of coherent superposition of extended spin waves in a finite chain in a homogeneous or weakly inhomogeneous field transforms into magnon Bloch oscillations of the superposition of localized Wannier–Zeeman states in a strongly inhomogeneous field. We provide a semiclassical description of the magnon Bloch oscillations and show that the correspondence between the quantum and semiclassical descriptions is most accurate for Bloch oscillations of the magnon coherent states, which are built from a coherent superposition of a large number of the nearest-neighbour Wannier–Zeeman states. (paper)

  2. Exact solutions and ladder operators for a new anharmonic oscillator

    International Nuclear Information System (INIS)

    Dong Shihai; Sun Guohua; Lozada-Cassou, M.

    2005-01-01

    In this Letter, we propose a new anharmonic oscillator and present the exact solutions of the Schrodinger equation with this oscillator. The ladder operators are established directly from the normalized radial wave functions and used to evaluate the closed expressions of matrix elements for some related functions. Some comments are made on the general calculation formula and recurrence relation for off-diagonal matrix elements. Finally, we show that this anharmonic oscillator possesses a hidden symmetry between E(r) and E(ir) by substituting r->ir

  3. Analysis of an "off-ladder" allele at the Penta D short tandem repeat locus.

    Science.gov (United States)

    Yang, Y L; Wang, J G; Wang, D X; Zhang, W Y; Liu, X J; Cao, J; Yang, S L

    2015-11-25

    Kinship testing of a father and his son from Guangxi, China, the location of the Zhuang minority people, was performed using the PowerPlex® 18D System with a short tandem repeat typing kit. The results indicated that both the father and his son had an off-ladder allele at the Penta D locus, with a genetic size larger than that of the maximal standard allelic ladder. To further identify this locus, monogenic amplification, gene cloning, and genetic sequencing were performed. Sequencing analysis demonstrated that the fragment size of the Penta D-OL locus was 469 bp and the core sequence was [AAAGA]21, also called Penta D-21. The rare Penta D-21 allele was found to be distributed among the Zhuang population from the Guangxi Zhuang Autonomous Region of China; therefore, this study improved the range of DNA data available for this locus and enhanced our ability for individual identification of gene loci.

  4. Implantable bladder volume sensor based on resistor ladder network composed of conductive hydrogel composite.

    Science.gov (United States)

    Mi Kyung Kim; Hyojung Kim; Jung, Yeon Su; Adem, Kenana M A; Bawazir, Sarah S; Stefanini, Cesare; Lee, Hyunjoo J

    2017-07-01

    An accurate bladder volume monitoring system is a critical component in diagnosis and treatment of urological disorders. Here, we report an implantable bladder volume sensor with a multi-level resistor ladder which estimates the bladder volume through discrete resistance values. Discretization allows the sensor output to be resilient to the long-term drift, hysteresis, and degradation of the sensor materials. Our sensor is composed of biocompatible polypyrrole/agarose hydrogel composite. Because Young's modulus of this composite is comparable to that of the bladder wall, the effect of mechanical loading of the sensor on the bladder movement is minimized which allows more accurate volume monitoring. We also demonstrate the patterning and molding capability of this material by fabrication various structures. Lastly, we successfully demonstrate the functionality of the multi-level resistor ladder sensor as a bladder volume sensor by attaching the sensor on the pig's bladder and observing the impedance change of the sensor.

  5. Symmetry protected topological Luttinger liquids and the phase transition between them

    Energy Technology Data Exchange (ETDEWEB)

    None

    2018-01-01

    We show that a doped spin-1/2 ladder with antiferromagnetic intra-chain and ferromagnetic inter-chain coupling is a symmetry protected topologically non-trivial Luttinger liquid. Turning on a large easy-plane spin anisotropy drives the system to a topologically-trivial Luttinger liquid. Both phases have full spin gaps and exhibit power-law superconducting pair correlation. The Cooper pair symmetry is singlet $d_{xy}$ in the non-trivial phase and triplet $S_z=0$ in the trivial phase. The topologically non-trivial Luttinger liquid exhibits gapless spin excitations in the presence of a boundary, and it has no non-interacting or mean-field theory analog even when the fluctuating phase in the charge sector is pinned. As a function of the strength of spin anisotropy there is a topological phase transition upon which the spin gap closes. We speculate these Luttinger liquids are relevant to the superconductivity in metalized integer spin ladders or chains.

  6. Intelligent Smoke Alarm System with Wireless Sensor Network Using ZigBee

    Directory of Open Access Journals (Sweden)

    Qin Wu

    2018-01-01

    Full Text Available The conflagration of fire is still a serious problem caused by humans, and houses are at a high risk of fire. Recently, people have used smoke alarms which only have one sensor to detect fire. Smoke is emitted in several forms in daily life. A single sensor is not a reliable way to detect fire. With the rapid advancement in Internet technology, people can monitor their houses remotely to determine the current condition of the house. This paper introduces an intelligent smoke alarm system that uses ZigBee transmission technology to build a wireless network, uses random forest to identify smoke, and uses E-charts for data visualization. By combining the real-time dynamic changes of various environmental factors, compared to the traditional smoke alarm, the accuracy and controllability of the fire warning are increased, and the visualization of the data enables users to monitor the room environment more intuitively. The proposed system consists of a smoke detection module, a wireless communication module, and intelligent identification and data visualization module. At present, the collected environmental data can be classified into four statuses, that is, normal air, water mist, kitchen cooking, and fire smoke. Reducing the frequency of miscalculations also means improving the safety of the person and property of the user.

  7. New phenazine-containing ladder polymer of intrinsic microporosity from a spirobisindane-based AB-type monomer

    KAUST Repository

    Ghanem, Bader; Alghunaimi, Fahd; Alaslai, Nasser Y.; Ma, Xiaohua; Pinnau, Ingo

    2016-01-01

    . This protocol can be used to prepare a variety of phenazine-containing ladder type PIMs from their aromatic tetramethoxy precursors. The obtained polymer had high average molecular mass, excellent thermal stability, a high BET surface area of 705 m(2) g(-1

  8. New phenazine-containing ladder polymer of intrinsic microporosity from a spirobisindane-based AB-type monomer

    KAUST Repository

    Ghanem, Bader

    2016-08-15

    A new solution-processable ladder polymer (PSBI-AB) of intrinsic microporosity with dibenzodioxane linkages and bis(phenazine) units was designed and synthesized by self-polymerization of an AB-type monomer containing both catechol and aromatic dichloride groups. Such polymerization is an effective way to synthesize high molecular weight polymers and has a significant advantage over AA-BB polycondensation due to the lack of the requirement for strict control over stoichiometric balance. This protocol can be used to prepare a variety of phenazine-containing ladder type PIMs from their aromatic tetramethoxy precursors. The obtained polymer had high average molecular mass, excellent thermal stability, a high BET surface area of 705 m(2) g(-1) and good solubility in some organic solvents such as chloroform, m-cresol and dichlorobenzene. Gas permeation measurements showed comparable results to the previously reported analogous PIM-7 for films made under the same formation protocol.

  9. Entangled spins and ghost-spins

    Directory of Open Access Journals (Sweden)

    Dileep P. Jatkar

    2017-09-01

    Full Text Available We study patterns of quantum entanglement in systems of spins and ghost-spins regarding them as simple quantum mechanical toy models for theories containing negative norm states. We define a single ghost-spin as in [20] as a 2-state spin variable with an indefinite inner product in the state space. We find that whenever the spin sector is disentangled from the ghost-spin sector (both of which could be entangled within themselves, the reduced density matrix obtained by tracing over all the ghost-spins gives rise to positive entanglement entropy for positive norm states, while negative norm states have an entanglement entropy with a negative real part and a constant imaginary part. However when the spins are entangled with the ghost-spins, there are new entanglement patterns in general. For systems where the number of ghost-spins is even, it is possible to find subsectors of the Hilbert space where positive norm states always lead to positive entanglement entropy after tracing over the ghost-spins. With an odd number of ghost-spins however, we find that there always exist positive norm states with negative real part for entanglement entropy after tracing over the ghost-spins.

  10. Possible sea sediments due to glaciofluvial activity in Elysium Planitia, Mars

    Science.gov (United States)

    Nussbaumer, J.

    Observations of fluvial morphologies in southern Elysium Planitia strongly supports the hypothesis that water substantially affected this region during the relatively recent geologic past. As of yet, however, the extent of a standing body of water has been speculative. The observation of zig-zag features potentially analogous to those observed near the Wadden Sea on Earth [see 1] may help show in more detail the origin, activity, and fate of water in this region of Mars. These terrestrial analogs could constrain environmental scenarios concerning the formation of these features. We present a geomorphologic map of central Elysium Planitia, that aids in our interpretation of potentially site-specific depositional/erosional morphologies. Positive relief zig-zag features within the Medusae Fossae Formation (Themis Image V05875001) resemble similar structures on Earth observed at shorelines of flat regions. Glaciofluvial activity is indicated by linear features resembling straight glacial flutings, which could form aeolian yardangs subsequently. The flutings are associated with branches of inverted fluvial channels (Images Themis V05588002, MOC e1800307). Their excavated positive relief (height ~40 m) indicates, that the adjacent material was eroded by sublimation or aeolian activity. The channels possibly resemble ice marginal channels. A high resolution Digital Terrain Model of one of the channels suggests, that one channel is possibly running upslope. Fluvial processes could have operated at one location at one time, and glacial processes at another location at another time [2]. A glacial drainage system [see 3] is a possible terrestrial analog for one inverted fluvial channel on Mars (Themis Image V05875001). Flutings occur on the foreland of many glaciers and their length may provide important evidence for rapid advance over substantial distances. Flutings are the product of subglacial erosion and transport processes [4]. By assigning the different environmental

  11. Malthus on long swings: the general case.

    Science.gov (United States)

    Dooley, P C

    1988-02-01

    3 major assumptions provided the basis to Malthus' theory of population: food is necessary to human existence; passion between man and woman is necessary and will continue nearly in its present state; and the power of population is indefinitely greater than the earth's power to produce subsistence for humans. With this as his base, Malthus proposed the thesis that strong and constant forces need to hold the superior power of population over subsistence in check. The forces include both positive checks, e.g., infant mortality, and preventive checks, e.g., foregoing early marriage. Malthus evidently had a theory of long swings in mind because he began his essay questioning whether humankind will experience unlimited improvement or a state oscillating between happiness and misery. Waterman (1987) offers a new interpretation of Malthus' theory of long swings, concluding that "the Malthusian theory of oscillations' as sketched in the 'Essay on Population' may justly be represented by a zig-zag path of real wages." 2 questions arise: does the text literally mean what Waterman suggests; and is the text consistent with Malthus' general position. The quotation offered by Wasserman focuses on a special case that illustrates how oscillations might take place but fails to represent Malthus' general position. In any society the population's response to wages determines the "level" of subsistence. Due to the different living habits in each state, the subsistence level varies from state to state, and Malthus devotes much of the 1st "Essay" to discussing what determines the living habits and the subsistence level in different countries. In Malthus' theory of long swings, real wages do not follow a "zig-zag" path. This is due to the fact that neither the accumulation of capital nor the growth of population behaves as he proposes. Whenever the rate of profit is sufficiently attractive, capital accumulates, and the response of population to a change in wages depends on a complex of

  12. Systematic Review of the Research on Motor Fitness of 1st-Year Students Attending Polish Institutions of Higher Education

    Directory of Open Access Journals (Sweden)

    Robert Podstawski

    2013-10-01

    Full Text Available Aim of the study. To establish: 1 the amount of research on general motor fitness of 1st-year students, conducted at selected Polish institutions of higher education between 1953-2010; 2 the number and kind of motor tests applied in this kind of research as well as the frequency of these tests during the period under study. Material and methods: The material for this research was composed of the publications on motor fitness of the first-year students taking part in specific motor trials applied at Polish tertiary institutions between 1953 - 2010. A diagnostic poll method was used in the research. Results: Fifty-four original research cases conducted in the period under study were observed. Within this period the trials such as: “100m run”, “jump from the run-up”, “grenade throw” and “ shot put” were more popular during the earlier years, while the trials such us: “zig-zag run”, “standing long jump”, and “medicine ball throw” were characteristic of more recent studies. Some of the most popular motor trials were: “standing long jump” – 38 cases, “medicine ball throw” – 30 cases, “zig-zag run” – 28 cases, “shuttle runs” – 9 cases, "short distance runs” – 12 cases, “downward bend from standing position” – 10 cases, and "vertical jump” – 8 cases. Conclusions: 1. Little research concerning the level of physical fitness of first-year students attending Polish tertiary institutions was conducted in the years 1953-2010; 2. The amount of motor fitness research carried out during this period fails to provide constant systematic assessment of the state of the students’ physical condition, which is a result of too large dispersions in time and territory where the measurements were taken; 3. In the motor fitness tests conducted with 1st-year students the determining variable was mainly gender, and only few research cases were found in which general motor fitness was analyzed according to

  13. A stowing and deployment strategy for large membrane space systems on the example of Gossamer-1

    Science.gov (United States)

    Seefeldt, Patric

    2017-09-01

    Deployment systems for innovative space applications such as solar sails require a technique for a controlled and autonomous deployment in space. The deployment process has a strong impact on the mechanism and structural design and sizing. On the example of the design implemented in the Gossamer-1 project of the German Aerospace Center (DLR), such a stowing and deployment process is analyzed. It is based on a combination of zig-zag folding and coiling of triangular sail segments spanned between crossed booms. The deployment geometry and forces introduced by the mechanism considered are explored in order to reveal how the loads are transferred through the membranes to structural components such as the booms. The folding geometry and force progressions are described by function compositions of an inverse trigonometric function with the considered trigonometric function itself. If these functions are evaluated over several periods of the trigonometric function, a non-smooth oscillating curve occurs. Depending on the trigonometric function, these are often vividly described as zig-zag or sawtooth functions. The developed functions are applied to the Gossamer-1 design. The deployment geometry reveals a tendency that the loads are transferred along the catheti of the sail segments and therefore mainly along the boom axes. The load introduced by the spool deployment mechanism is described. By combining the deployment geometry with that load, a prediction of the deployment load progression is achieved. The mathematical description of the stowing and deployment geometry, as well as the forces inflicted by the mechanism provides an understanding of how exactly the membrane deploys and through which edges the deployment forces are transferred. The mathematical analysis also gives an impression of sensitive parameters that could be influenced by manufacturing tolerances or unsymmetrical deployment of the sail segments. While the mathematical model was applied on the design of

  14. A computer simulation study of tilted smectic mesophases

    International Nuclear Information System (INIS)

    Withers, I.M.

    2000-05-01

    Results are presented from a series of simulations undertaken to determine the effect of a novel form of molecular biaxiality upon the phase behaviour of the well established Gay-Berne (GB) liquid crystal model. Firstly, the simulation of a bulk system interacting via the Internally-Rotated Gay Berne (IRGB) potential, which offers a single-site representation of a molecule rigidly constrained into a zig-zag conformation, is presented. The results of simulations performed for systems of IRGB particles with an aspect ratio of 3:1 confirm that the introduction of biaxiality into the model results in the destabilisation of the orientationally ordered phases. For particles with a sufficiently pronounced zig-zag conformation, this results in the complete destabilisation of the smectic A phase and the smectic B phase being replaced by the tilted smectic J phase. Following these observations, the effect upon the phase behaviour of increasing molecular elongation is also considered, with an increase in the aspect ratio from 3:1 to 4:1 resulting in the nematic and smectic J phases being replaced by smectic A and smectic G phases respectively. Secondly, a version of the IRGB potential modified to include a degree of molecular flexibility is considered. Results obtained from bulk systems interacting via the flexible IRGB for 3:1 and 4:1 molecules show that the introduction of flexibility results in the destabilisation of the smectic A phase and the stabilisation of the nematic and tilted hexatic phases. Finally, the effect upon the phase behaviour of the rigid IRGB model of the inclusion of a longitudinal linear quadrupole is examined. These results show that increasing quadrupole moment results in the destabilisation of the tilted hexatic phase, although the biaxial order parameter is increased with increasing quadrupole moment. There is no clear correlation between quadrupole magnitude and the other observed phase transitions, with the nematic and smectic A phases being

  15. Supramolecular assemblies in [Cu(L-Arg){sub 2}(H{sub 2}O)]C{sub 2}O{sub 4}·6H{sub 2}O complex – Structural, spectroscopic, magnetic and thermal behavior

    Energy Technology Data Exchange (ETDEWEB)

    Wojciechowska, Agnieszka, E-mail: agnieszka.wojciechowska@pwr.edu.pl [Faculty of Chemistry, Wroclaw University of Technology, Wybrzeze Wyspiańskiego 27, 50-370, Wrocław (Poland); Kochel, Andrzej [Faculty of Chemistry, University of Wroclaw, F. Joliot-Curie 14, 50-383, Wrocław (Poland); Duczmal, Marek [Faculty of Chemistry, Wroclaw University of Technology, Wybrzeze Wyspiańskiego 27, 50-370, Wrocław (Poland)

    2016-10-01

    The reaction of L-arginine and oxalate ions with copper(II) salts yields a new complex with formula of [Cu(L-Arg){sub 2}(H{sub 2}O)]·C{sub 2}O{sub 4}·6H{sub 2}O (1) (where L-Arg = L-arginine). Single crystals of 1 were synthesized by crystallization from aqueous solution. The complex properties were characterized by X-ray diffraction, spectroscopy (FT-IR, FT-Raman, NIR-Vis-UV and EPR) as well as thermal and magnetic methods. The square pyramidal (SP) geometry around Cu(II) ions in [Cu(L-Arg){sub 2}(H{sub 2}O)]{sup 2+} cation complex is formed by two cis-chelated L-arginine zwitterions and a water molecule coordinated in the apex of square pyramid. The trigonality distortion of SP geometry is relatively small, τ = 0.0087. The solid state EPR spectrum showed broad hyperfine splitting with g{sub ⊥} = 2.061 at 77 K. The copper centres distanced at 7.558(5) Å are joined in a single zig-zag structure via a chain based on the combination of Cu−O(5)−H(29)⋯O(2)−C1−O1−Cu hydrogen bonds along the b axis (d (O2⋯O5) = 2.812 Å). Taking into account the structural features, the magnetic susceptibility data were best-fitted, giving the exchange parameter J = −0.16 cm{sup −1}. Complex 1 is thermally stable up to 66 °C, where it was observed to lose the crystallization water molecules with an 11.7% mass loss (calc. 11.5%). - Highlights: • Crystal and molecular structure of [Cu(L-Arg){sub 2}(H{sub 2}O)]C{sub 2}O{sub 4}·6H{sub 2}O crystals have been studied. • The magnetic interactions of Cu(II) centres are assisted by the formation of single zig-zag chain. • Role of oxalate ions in completed relatively small square pyramid distortion is described. • The cis-fashioned L-arginine created the stronger ligand field than trans-configuration.

  16. Raúl Ruiz: Ontología de lo Fantástico. Territorios, Políticas Estéticas y Polisemia Visual Raúl Ruiz: Ontology of the Fantastic. Territory, Aesthetics Policies, and Visual Polysemy

    Directory of Open Access Journals (Sweden)

    Adolfo Vásquez Rocca

    2010-12-01

    Full Text Available El cine de Raúl Ruiz nace de una continua reflexión acerca de los modos narrativos cinematográficos. Ruiz configura en Francia un cine exploratorio, experimental y barroco, que indaga en la falta de identidad y la pérdida del territorio. Es en su poética donde logra infiltrar su disidencia, su condición de exiliado metafísico, que encuentra su militancia en la lucha contra el núcleo ideológico de la teoría del conflicto central, que no es sino la operacionalización narrativa de los mecanismos de la competencia, característica del modelo neoliberal. La forma de polisemia visual que Ruiz pone en operación consiste en mirar una película cuya lógica narrativa aparente sigue siempre una misma historia, y cuyos vagabundeos, fallas, recorridos en zig-zag, se explican por su plan secreto, esto es por una película impostora, no explícita, cuyos puntos fuertes se ubican en los momentos débiles de la película aparente, para desde allí narrar otra historia, crear una obra que juegue con la película aparente, que la contradiga y especule sobre ella.The cinema of Raúl Ruiz comes from an ongoing reflection on the narrative modes of cinema. Ruiz sets in France an exploratory cinema, experimental and Baroque, which explores the lack of identity and loss of territory. It's in his poetic where he manages to infiltrate his dissent, his metaphysical exile, and his militancy in the struggle against the ideological core of the central theoretical conflict: the storytelling of the mechanisms of competition that is characteristic of neoliberal models. The form of visual polysemy that Ruiz put into operation consists of watching a film that has narrative logic that are apparently always the same; its wanderings, failures, zig-zag paths are explained by a sort of secret plan, an impostor film that is not explicit, and whose strengths lie in the weak moments of the film that seem to tell another story, creating a work that plays with the film, and

  17. Third-order differential ladder operators and supersymmetric quantum mechanics

    International Nuclear Information System (INIS)

    Mateo, J; Negro, J

    2008-01-01

    Hierarchies of one-dimensional Hamiltonians in quantum mechanics admitting third-order differential ladder operators are studied. Each Hamiltonian has associated three-step Darboux (pseudo)-cycles and Painleve IV equations as a closure condition. The whole hierarchy is generated applying some operations on the cycles. These operations are investigated in the frame of supersymmetric quantum mechanics and mainly involve algebraic manipulations. A consistent geometric representation for the hierarchy and cycles is built that also helps in understanding the operations. Three kinds of hierarchies are distinguished and a realization based on the harmonic oscillator Hamiltonian is supplied, giving an interpretation for the spectral properties of the Hamiltonians of each hierarchy

  18. Simulation of TunneLadder traveling-wave tube cold-test characteristics: Implementation of the three-dimensional, electromagnetic circuit analysis code micro-SOS

    Science.gov (United States)

    Kory, Carol L.; Wilson, Jeffrey D.

    1993-01-01

    The three-dimensional, electromagnetic circuit analysis code, Micro-SOS, can be used to reduce expensive time-consuming experimental 'cold-testing' of traveling-wave tube (TWT) circuits. The frequency-phase dispersion characteristics and beam interaction impedance of a TunneLadder traveling-wave tube slow-wave structure were simulated using the code. When reasonable dimensional adjustments are made, computer results agree closely with experimental data. Modifications to the circuit geometry that would make the TunneLadder TWT easier to fabricate for higher frequency operation are explored.

  19. Spin Current Noise of the Spin Seebeck Effect and Spin Pumping

    Science.gov (United States)

    Matsuo, M.; Ohnuma, Y.; Kato, T.; Maekawa, S.

    2018-01-01

    We theoretically investigate the fluctuation of a pure spin current induced by the spin Seebeck effect and spin pumping in a normal-metal-(NM-)ferromagnet(FM) bilayer system. Starting with a simple ferromagnet-insulator-(FI-)NM interface model with both spin-conserving and non-spin-conserving processes, we derive general expressions of the spin current and the spin-current noise at the interface within second-order perturbation of the FI-NM coupling strength, and estimate them for a yttrium-iron-garnet-platinum interface. We show that the spin-current noise can be used to determine the effective spin carried by a magnon modified by the non-spin-conserving process at the interface. In addition, we show that it provides information on the effective spin of a magnon, heating at the interface under spin pumping, and spin Hall angle of the NM.

  20. The Earnings Ladder. Who's at the Bottom? Who's at the Top? Statistical Brief.

    Science.gov (United States)

    Bureau of the Census (DOC), Washington, DC. Economics and Statistics Administration.

    Data collected by the March Current Population Survey were used to identify which groups of year-round, full-time civilian workers aged 16 and older were most likely to be at the top and bottom of the earnings ladder. Women, young workers, less-educated individuals, and Hispanics were most likely to earn less than $13,091 (1992 constant dollars),…

  1. Academic Profile of Bachelor of Technical Teacher Education Ladder I Students as Ba sis for an Intervention Program

    Directory of Open Access Journals (Sweden)

    Arly B. Balingbing

    2017-05-01

    Full Text Available This study aimed to determine: the academic profile of Bachelor of Technical Teacher Education ( BTTE Ladder 1 students in terms of entrance examination, GWM in GEC subjects and TESDA Competency Assessment; their strengths and weaknesses along TESDA Assessment; the significant relationship between Entrance Examination & GWA, GWA & TESDA Competency and Entrance Examination & TESDA Compe tency, the significant interrelationship among the three variables; and the program or intervention which could be proposed to improve their academic performance. Data were gathered from one hundred fifty eight ( 158 BTTE Ladder 1 graduates of SY 2014 - 2016 through a questionnaire and documentary analysis and were statistically treated using percentage, weighted mean, Spearman’s rho and multiple coefficients. The researcher concluded that BTTE Ladder 1 students are competent as assessed by TESDA despite bein g low in entrance examination. Their weaknesses lie along communication and comprehension but they prove to be capable also on the condition that Filipino language is used and questions are repeated or rephrased. They also lack exposure to the tools and eq uipment used their field. Their strength is evident in performing the task but not in explaining the process. Both the Entrance Examination & GWA, GWM & TESDA Competency and Entrance Exam & TESDA Competency are significantly interrelated.

  2. El enfoque de los sistemas dinámicos en el aprendizaje del bote en baloncesto en un contexto escolar

    Directory of Open Access Journals (Sweden)

    Fernando S\\u00E1nchez Ba\\u00F1uelos

    2005-01-01

    Full Text Available En este articulo tratamos de demostrar la teoría de los sistemas dinámicos. Se realizó un diseño cuasiexperimental con dos grupos intactos no equivalentes. Grupo experimental (GE:25; grupo de control (GC:20; con medidas pretest y postest. La variable independiente fue la utilización de unas gafas limitadoras de visión. La variable dependiente fue el tiempo mínimo en la ejecución de test de habilidad en el bote. La unidad didáctica de 7 sesiones era de fundamentos técnicos en baloncesto. Los resultados muestran como se han producido mejoras muy significativas (p<0,001 en el test de bote en zig-zag en el GE, aunque tambien existen mejoras en el grupo de control utilizando un modelo de enseñanza-aprendizaje convencional en EF.

  3. AEMnSb2 (AE=Sr, Ba): a new class of Dirac materials

    International Nuclear Information System (INIS)

    Farhan, M Arshad; Lee, Geunsik; Shim, Ji Hoon

    2014-01-01

    The Dirac fermions of Sb square net in AEMnSb 2 (AE=Sr, Ba) are investigated by using first-principles calculation. BaMnSb 2 contains Sb square net layers with a coincident stacking of Ba atoms, exhibiting Dirac fermion behavior. On the other hand, SrMnSb 2 has a staggered stacking of Sr atoms with distorted zig-zag chains of Sb atoms. Application of hydrostatic pressure on the latter induces a structural change from a staggered to a coincident arrangement of AE ions accompanying a transition from insulator to a metal containing Dirac fermions. The structural investigations show that the stacking type of cation and orthorhombic distortion of Sb layers are the main factors to decide the crystal symmetry of the material. We propose that the Dirac fermions can be obtained by controlling the size of cation and the volume of AEMnSb 2 compounds. (fast track communication)

  4. One- and two-cluster synchronized dynamics of non-diffusively coupled Tchebycheff map networks

    International Nuclear Information System (INIS)

    Schäfer, Mirko; Greiner, Martin

    2012-01-01

    We use the master stability formalism to discuss one- and two-cluster synchronization of coupled Tchebycheff map networks. For diffusively coupled map systems, the one-cluster synchronized dynamics is given by the behaviour of the individual maps, and the coupling only determines the stability of the coherent state. For the case of non-diffusive coupling and for two-cluster synchronization, the synchronized dynamics on networks is different from the behaviour of the single individual map. Depending on the coupling, we study numerically the characteristics of various forms of the resulting synchronized dynamics. The stability properties of the respective one-cluster synchronized states are discussed for arbitrary network structures. For the case of two-cluster synchronization on bipartite networks we also present analytical expressions for fixed points and zig-zag patterns, and explicitly determine the linear stability of these orbits for the special case of ring-networks.

  5. Mode-locking via dissipative Faraday instability.

    Science.gov (United States)

    Tarasov, Nikita; Perego, Auro M; Churkin, Dmitry V; Staliunas, Kestutis; Turitsyn, Sergei K

    2016-08-09

    Emergence of coherent structures and patterns at the nonlinear stage of modulation instability of a uniform state is an inherent feature of many biological, physical and engineering systems. There are several well-studied classical modulation instabilities, such as Benjamin-Feir, Turing and Faraday instability, which play a critical role in the self-organization of energy and matter in non-equilibrium physical, chemical and biological systems. Here we experimentally demonstrate the dissipative Faraday instability induced by spatially periodic zig-zag modulation of a dissipative parameter of the system-spectrally dependent losses-achieving generation of temporal patterns and high-harmonic mode-locking in a fibre laser. We demonstrate features of this instability that distinguish it from both the Benjamin-Feir and the purely dispersive Faraday instability. Our results open the possibilities for new designs of mode-locked lasers and can be extended to other fields of physics and engineering.

  6. Geometrical spin symmetry and spin

    International Nuclear Information System (INIS)

    Pestov, I. B.

    2011-01-01

    Unification of General Theory of Relativity and Quantum Mechanics leads to General Quantum Mechanics which includes into itself spindynamics as a theory of spin phenomena. The key concepts of spindynamics are geometrical spin symmetry and the spin field (space of defining representation of spin symmetry). The essence of spin is the bipolar structure of geometrical spin symmetry induced by the gravitational potential. The bipolar structure provides a natural derivation of the equations of spindynamics. Spindynamics involves all phenomena connected with spin and provides new understanding of the strong interaction.

  7. Telecast of Astronaut Neil Armstrong descending ladder to surface of the moon

    Science.gov (United States)

    1969-01-01

    Astronaut Neil A. Armstrong, Apollo 11 commander, descends the ladder of the Apollo 11 Lunar Module prior to making the first step by man on the moon. This view is a black and white reproduction taken from a telecast by the Apollo 11 lunar surface camera during extravehicular activity. The black bar running through the center of the picture is an anamoly in the television ground data system at the Goldstone Tracking Station.

  8. The zig-zag walk with scattering and absorption on the real half line and in a lattice model

    Science.gov (United States)

    Wuttke, Joachim

    2014-05-01

    The Darwin-Hamilton equations, describing one-dimensional transport with scattering and absorption, are expanded into a recursion. The solution involves ballot numbers. The recurrence probability as function of scattering order is given by Catalan numbers. To reproduce this analytical result in a lattice model, a novel relation between Narayana and Catalan numbers is derived.

  9. Creating a palliative and end-of-life program in a cure-oriented pediatric setting: the zig-zag method.

    Science.gov (United States)

    Harper, Joann; Hinds, Pamela S; Baker, Justin N; Hicks, Judy; Spunt, Sheri L; Razzouk, Bassem I

    2007-01-01

    Children living with and dying of advanced-stage cancer suffer physically, emotionally, and spiritually. Relief of their suffering requires comprehensive, compassionate palliative and end-of-life (EoL) care.However, an EoL care program might appear inconsistent with the mission of a pediatric oncology research center committed to seeking cures. Here the authors describe the methods used to achieve full institutional commitment to their EoL care program and those used to build the program's philosophical, research, and educational foundations after they received approval. The authors convened 10 focus groups to solicit staff perceptions of the hospital's current palliative and EoL care. They also completed baseline medical record reviews of 145 patient records to identify key EoL characteristics. The authors then crafted a vision statement and a strategic plan, implemented new research protocols,and established publication and funding trajectories. They conclude that establishing a state-of-the-art palliative and EoL program in a cure-oriented pediatric setting is achievable via consensus building and recruitment of diverse institutional resources.

  10. Optimization Study of Hydrogen Gas Adsorption on Zig-zag Single-walled Carbon Nanotubes: The Artificial Neural Network Analysis

    Science.gov (United States)

    Nasruddin; Lestari, M.; Supriyadi; Sholahudin

    2018-03-01

    The use of hydrogen gas in fuel cell technology has a huge opportunity to be applied in upcoming vehicle technology. One of the most important problems in fuel cell technology is the hydrogen storage. The adsorption of hydrogen in carbon-based materials attracts a lot of attention because of its reliability. This study investigated the adsorption of hydrogen gas in Single-walled Carbon Nano Tubes (SWCNT) with chilarity of (0, 12), (0, 15), and (0, 18) to find the optimum chilarity. Artificial Neural Networks (ANN) can be used to predict the hydrogen storage capacity at different pressure and temperature conditions appropriately, using simulated series of data. The Artificial Neural Network is modeled as a predictor of the hydrogen adsorption capacity which provides solutions to some deficiencies in molecular dynamics (MD) simulations. In a previous study, ANN configurations have been developed for 77k, 233k, and 298k temperatures in hydrogen gas storage. To prepare this prediction, ANN is modeled to find out the configurations that exist in the set of training and validation of specified data selection, the distance between data, and the number of neurons that produce the smallest error. This configuration is needed to make an accurate artificial neural network. The configuration of neural network was then applied to this research. The neural network analysis results show that the best configuration of artificial neural network in hydrogen storage is at 233K temperature i.e. on SWCNT with chilarity of (0.12).

  11. Fish passage post-construction issues: analysis of distribution, attraction and passage efficiency metrics at the Baguari Dam fish ladder to approach the problem

    Directory of Open Access Journals (Sweden)

    Luiz Gustavo Martins da Silva

    Full Text Available Fish passages are considered the oldest management tool used to minimize the impact of blocking fish migratory routes by hydroelectric power plants. However, fish passages are being installed without specific criteria in Brazil, with severe consequences to the conservation of the local fish fauna. Therefore, basic data gathered for fish passages already constructed could contribute to define operational rules, in addition to offer subsidies to decision-making and design of future facilities. Thus, the fish ladder of Baguari Dam was evaluated regarding temporal distribution, attraction, and ascension of the local fish fauna. A total of 20 fish samples were conducted immediately downstream of the dam and inside the fish ladder, from January 2010 to June 2011. Seasonal variation in fish abundance and richness was registered below the dam and inside the passage, with higher number of migratory fish in the reproductive season (Kruskall-Wallis, p = 0.04 and p = 0.05. Furthermore, higher concentration of migratory allochthonous and non-migratory species was registered for the spill bay (Wilcoxon, p = 0.009 and p = 0.006 compared to the tailrace, where the fish ladder entrance is located. This result suggests low efficiency of the attraction system of the mechanism during the reproductive period. Once entering the fish ladder, migratory species apparently ascend the facility due to the similar distribution throughout different stretches. Generally, the results showed that an operational rule for the Baguari Dam fish ladder should consider running the facility only during the reproductive period, unless the objectives of the passage are well defined. The attraction system must be more precisely evaluated, using technologies such as radiotelemetry. Similarly, fish ascension also should be better analyzed to evaluate the time spent to ascend and its influence in the reproductive biology of the species using the ladder. Pit-tag system could be used to

  12. Spin Torques in Systems with Spin Filtering and Spin Orbit Interaction

    KAUST Repository

    Ortiz Pauyac, Christian

    2016-06-19

    In the present thesis we introduce the reader to the field of spintronics and explore new phenomena, such as spin transfer torques, spin filtering, and three types of spin-orbit torques, Rashba, spin Hall, and spin swapping, which have emerged very recently and are promising candidates for a new generation of memory devices in computer technology. A general overview of these phenomena is presented in Chap. 1. In Chap. 2 we study spin transfer torques in tunnel junctions in the presence of spin filtering. In Chap. 3 we discuss the Rashba torque in ferromagnetic films, and in Chap. 4 we study spin Hall effect and spin swapping in ferromagnetic films, exploring the nature of spin-orbit torques based on these mechanisms. Conclusions and perspectives are summarized in Chap. 5.

  13. SU(3)_C× SU(2)_L× U(1)_Y( × U(1)_X ) as a symmetry of division algebraic ladder operators

    Science.gov (United States)

    Furey, C.

    2018-05-01

    We demonstrate a model which captures certain attractive features of SU(5) theory, while providing a possible escape from proton decay. In this paper we show how ladder operators arise from the division algebras R, C, H, and O. From the SU( n) symmetry of these ladder operators, we then demonstrate a model which has much structural similarity to Georgi and Glashow's SU(5) grand unified theory. However, in this case, the transitions leading to proton decay are expected to be blocked, given that they coincide with presumably forbidden transformations which would incorrectly mix distinct algebraic actions. As a result, we find that we are left with G_{sm} = SU(3)_C× SU(2)_L× U(1)_Y / Z_6. Finally, we point out that if U( n) ladder symmetries are used in place of SU( n), it may then be possible to find this same G_{sm}=SU(3)_C× SU(2)_L× U(1)_Y / Z_6, together with an extra U(1)_X symmetry, related to B-L.

  14. Spin-polarized spin excitation spectroscopy

    International Nuclear Information System (INIS)

    Loth, Sebastian; Lutz, Christopher P; Heinrich, Andreas J

    2010-01-01

    We report on the spin dependence of elastic and inelastic electron tunneling through transition metal atoms. Mn, Fe and Cu atoms were deposited onto a monolayer of Cu 2 N on Cu(100) and individually addressed with the probe tip of a scanning tunneling microscope. Electrons tunneling between the tip and the substrate exchange energy and spin angular momentum with the surface-bound magnetic atoms. The conservation of energy during the tunneling process results in a distinct onset threshold voltage above which the tunneling electrons create spin excitations in the Mn and Fe atoms. Here we show that the additional conservation of spin angular momentum leads to different cross-sections for spin excitations depending on the relative alignment of the surface spin and the spin of the tunneling electron. For this purpose, we developed a technique for measuring the same local spin with a spin-polarized and a non-spin-polarized tip by exchanging the last apex atom of the probe tip between different transition metal atoms. We derive a quantitative model describing the observed excitation cross-sections on the basis of an exchange scattering process.

  15. Online measurement of mental representations of complex spatial decision problems : comparison of CNET and hard laddering

    NARCIS (Netherlands)

    Horeni, O.; Arentze, T.A.; Dellaert, B.G.C.; Timmermans, H.J.P.

    2014-01-01

    This paper introduces the online Causal Network Elicitation Technique (CNET), as a technique for measuring components of mental representations of choice tasks and compares it with the more common technique of online 'hard' laddering (HL). While CNET works in basically two phases, one in open

  16. Influence of seasonal, diel, lunar, and other environmental factors on upstream fish passage in the igarapava fish ladder, Brazil

    Science.gov (United States)

    Bizzotto, P.M.; Godinho, Alexandre L.; Vono, V.; Kynard, B.; Godinho, Hugo P.

    2009-01-01

    Upstream fish passage was evaluated during 12 months in the vertical-slot Igarapava Fish Ladder constructed around Igarapava Dam, in the heavily dammed Grande River, Southeast Brazil. A video monitoring system was used to observe 61,621 fish that passed the ladder, of which 93.5% were identified to 15 taxa. Among the migratory species, the most abundant were Pimelodus maculatus (33.6% of all fish), Leporinus octofasciatus (31.4%), Leporinus friderici (4.5%), and Prochilodus lineatus (3.1%). Seven taxa were classified as nonmigratory, and of these taxa, the small Bryconamericus stramineus was the most abundant (12.7%) of all fishes. Passage of the 'nonmigratory' taxa upstream in the ladder shows they are migratory in this system and have a strong behavioural drive to move to upstream habitat. Passage of most taxa had a strong seasonal pattern. While some species passed primarily during the day, others showed a distinct nocturnal pattern. Lunar phase and water temperature also strongly affected passage of some taxa. Rainfall and dam discharge had a small or null influence on most taxa; perhaps due to the fairly small catchment area of the reservoir and the highly regulated discharge at Igarapava Dam. ?? 2009 John Wiley & Sons A/S.

  17. Development and Application of a ZigBee-Based Building Energy Monitoring and Control System

    Directory of Open Access Journals (Sweden)

    Changhai Peng

    2014-01-01

    Full Text Available Increasing in energy consumption, particularly with the ever-increasing growth and development of urban systems, has become a major concern in most countries. In this paper, the authors propose a cost-effective ZigBee-based building energy monitoring and control system (ZBEMCS, which is composed of a gateway, a base station, and sensors. Specifically, a new hardware platform for power sensor nodes is developed to perform both local/remote power parameter measurement and power on/off switching for electric appliances. The experimental results show that the ZBEMCS can easily monitor energy usage with a high level of accuracy. Two typical applications of ZBEMCS such as subentry metering and household metering of building energy are presented. The former includes lighting socket electricity, HVAC electricity, power electricity and special electricity. The latter includes household metering according to the campus’s main function zone and each college or department. Therefore, this system can be used for energy consumption monitoring, long-term energy conservation planning, and the development of automated energy conservation for building applications.

  18. Spin current and spin transfer torque in ferromagnet/superconductor spin valves

    Science.gov (United States)

    Moen, Evan; Valls, Oriol T.

    2018-05-01

    Using fully self-consistent methods, we study spin transport in fabricable spin valve systems consisting of two magnetic layers, a superconducting layer, and a spacer normal layer between the ferromagnets. Our methods ensure that the proper relations between spin current gradients and spin transfer torques are satisfied. We present results as a function of geometrical parameters, interfacial barrier values, misalignment angle between the ferromagnets, and bias voltage. Our main results are for the spin current and spin accumulation as functions of position within the spin valve structure. We see precession of the spin current about the exchange fields within the ferromagnets, and penetration of the spin current into the superconductor for biases greater than the critical bias, defined in the text. The spin accumulation exhibits oscillating behavior in the normal metal, with a strong dependence on the physical parameters both as to the structure and formation of the peaks. We also study the bias dependence of the spatially averaged spin transfer torque and spin accumulation. We examine the critical-bias effect of these quantities, and their dependence on the physical parameters. Our results are predictive of the outcome of future experiments, as they take into account imperfect interfaces and a realistic geometry.

  19. Online measurement of mental representations of complex spatial decision problems : Comparison of CNET and hard laddering

    NARCIS (Netherlands)

    O. Horeni (Oliver); T.A. Arentze (Theo); B.G.C. Dellaert (Benedict); H.J.P. Timmermans (Harry)

    2013-01-01

    textabstractThis paper introduces the online Causal Network Elicitation Technique (CNET), as a technique for measuring components of mental representations of choice tasks and compares it with the more common technique of online ‘hard’ laddering (HL). While CNET works in basically two phases, one in

  20. Pramana – Journal of Physics | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    legged S=1/2 spin ladders or spin tubes, have a singlet non-magnetic ground state and gap in the excitation spectrum. Their low-temperature properties can be described in terms of triplet massive quasiparticles. These magnons possess some ...

  1. Development and validation of a nursing professionalism evaluation model in a career ladder system.

    Science.gov (United States)

    Kim, Yeon Hee; Jung, Young Sun; Min, Ja; Song, Eun Young; Ok, Jung Hui; Lim, Changwon; Kim, Kyunghee; Kim, Ji-Su

    2017-01-01

    The clinical ladder system categorizes the degree of nursing professionalism and rewards and is an important human resource tool for managing nursing. We developed a model to evaluate nursing professionalism, which determines the clinical ladder system levels, and verified its validity. Data were collected using a clinical competence tool developed in this study, and existing methods such as the nursing professionalism evaluation tool, peer reviews, and face-to-face interviews to evaluate promotions and verify the presented content in a medical institution. Reliability and convergent and discriminant validity of the clinical competence evaluation tool were verified using SmartPLS software. The validity of the model for evaluating overall nursing professionalism was also analyzed. Clinical competence was determined by five dimensions of nursing practice: scientific, technical, ethical, aesthetic, and existential. The structural model explained 66% of the variance. Clinical competence scales, peer reviews, and face-to-face interviews directly determined nursing professionalism levels. The evaluation system can be used for evaluating nurses' professionalism in actual medical institutions from a nursing practice perspective. A conceptual framework for establishing a human resources management system for nurses and a tool for evaluating nursing professionalism at medical institutions is provided.

  2. Symmetry-broken states in a system of interacting bosons on a two-leg ladder with a uniform Abelian gauge field

    Science.gov (United States)

    Greschner, S.; Piraud, M.; Heidrich-Meisner, F.; McCulloch, I. P.; Schollwöck, U.; Vekua, T.

    2016-12-01

    We study the quantum phases of bosons with repulsive contact interactions on a two-leg ladder in the presence of a uniform Abelian gauge field. The model realizes many interesting states, including Meissner phases, vortex fluids, vortex lattices, charge density waves, and the biased-ladder phase. Our work focuses on the subset of these states that breaks a discrete symmetry. We use density matrix renormalization group simulations to demonstrate the existence of three vortex-lattice states at different vortex densities and we characterize the phase transitions from these phases into neighboring states. Furthermore, we provide an intuitive explanation of the chiral-current reversal effect that is tied to some of these vortex lattices. We also study a charge-density-wave state that exists at 1/4 particle filling at large interaction strengths and flux values close to half a flux quantum. By changing the system parameters, this state can transition into a completely gapped vortex-lattice Mott-insulating state. We elucidate the stability of these phases against nearest-neighbor interactions on the rungs of the ladder relevant for experimental realizations with a synthetic lattice dimension. A charge-density-wave state at 1/3 particle filling can be stabilized for flux values close to half a flux quantum and for very strong on-site interactions in the presence of strong repulsion on the rungs. Finally, we analytically describe the emergence of these phases in the low-density regime, and, in particular, we obtain the boundaries of the biased-ladder phase, i.e., the phase that features a density imbalance between the legs. We make contact with recent quantum-gas experiments that realized related models and discuss signatures of these quantum states in experimentally accessible observables.

  3. One-Particle vs. Two-Particle Crossover in Weakly Coupled Hubbard Chains and Ladders: Perturbative Renormalization Group Approach

    OpenAIRE

    Kishine, Jun-ichiro; Yonemitsu, Kenji

    1997-01-01

    Physical nature of dimensional crossovers in weakly coupled Hubbard chains and ladders has been discussed within the framework of the perturbative renormalization-group approach. The difference between these two cases originates from different universality classes which the corresponding isolated systems belong to.

  4. Impurity-induced staggered polarization and antiferromagnetic order in spin-12 Heisenberg two-leg ladder compound SrCu2O3: Extensive Cu NMR and NQR studies

    Science.gov (United States)

    Ohsugi, S.; Tokunaga, Y.; Ishida, K.; Kitaoka, Y.; Azuma, M.; Fujishiro, Y.; Takano, M.

    1999-08-01

    We report characteristics of impurity-induced staggered polarization (IISP) and antiferromagnetic long-range order (AF-LRO) in the gapped spin-1/2 Heisenberg two-leg ladder compound SrCu2O3 (Sr123). We have carried out comprehensive NMR and NQR investigations on three impurity-doped systems, Sr(Cu1-xMx)2O3 (M=Zn, Ni) with xIISP along the leg was found to be much longer than ξ0/a in x=0.001 and 0.005. The notable result is that ξs/a that was found to be T independent is scaled to mean distances DAV=1/(2x) between the Zn and Ni impurities and DAV=1/x between the La impurities. When DAV=500 for x=0.001 (Zn doping), ξs/a~50 is estimated. The significantly broadened NQR spectrum has provided unambiguous evidence for the AF-LRO in the Zn and Ni doping (x=0.01 and 0.02). Rather uniform AF moments at the middle Cu sites between the impurities are estimated to be about 0.04μB at 1.4 K along the a axis. By assuming that exponential decay constants of AF moments are equivalent to ξs/a's for the IISP, the size of an AF moment next to the impurity is deduced as SAF~1/4. We propose that these exponential distributions of IISP and AF moments along the two-leg suggest that an interladder interaction is in a weakly coupled quasi-one-dimensional (WC-Q1D) regime. The formula of TN=J0exp(-DAV/(ξs/a)) based on the WC-Q1D model explains TN(exp)=3 K (x=0.01) and 5.8 K (x=0.02) quantitatively and predicts to be as small as TN=0.09 K for x=0.001 using J0=2000 K. On the other hand, there is no evidence of AF-LRO for the La doping (x=0.02 and 0.03) down to 1.4 K, nevertheless their ξs/a's are almost equivalent to those in the Zn and Ni doping (x=0.01 and 0.02). We remark that the Q1D-IISP is dramatically enhanced by the interladder interaction even though so weak, once the impurity breaks up the quantum coherence in the short-range resonating valence bond (RVB) state with the gap. On the one hand, we propose that TN is determined by a strength of the interladder interaction and a size

  5. Spin current evolution in the separated spin-up and spin-down quantum hydrodynamics

    International Nuclear Information System (INIS)

    Trukhanova, Mariya Iv.

    2015-01-01

    We have developed a method of quantum hydrodynamics (QHD) that describes particles with spin-up and with spin-down in separate. We have derived the equation of the spin current evolution as a part of the set of the quantum hydrodynamics equations that treat particles with different projection of spin on the preferable direction as two different species. We have studied orthogonal propagation of waves in the external magnetic field and determined the contribution of quantum corrections due to the Bohm potential and to magnetization energy of particles with different projections of spin in the spin-current wave dispersion. We have analyzed the limits of weak and strong magnetic fields. - Highlights: • We derive the spin current equation for particles with different projection of spin. • We predict the contribution of Bohm potential to the dynamics of spin current. • We derive the spin-current wave in the system of spin-polarized particles. • We study the propagation of spin-acoustic wave in magnetized dielectrics.

  6. Muonium spin exchange in spin-polarized media: Spin-flip and -nonflip collisions

    International Nuclear Information System (INIS)

    Senba, M.

    1994-01-01

    The transverse relaxation of the muon spin in muonium due to electron spin exchange with a polarized spin-1/2 medium is investigated. Stochastic calculations, which assume that spin exchange is a Poisson process, are carried out for the case where the electron spin polarization of the medium is on the same axis as the applied field. Two precession signals of muonium observed in intermediate fields (B>30 G) are shown to have different relaxation rates which depend on the polarization of the medium. Furthermore, the precession frequencies are shifted by an amount which depends on the spin-nonflip rate. From the two relaxation rates and the frequency shift in intermediate fields, one can determine (i) the encounter rate of muonium and the paramagnetic species, (ii) the polarization of the medium, and most importantly (iii) the quantum-mechanical phase shift (and its sign) associated with the potential energy difference between electron singlet and triplet encounters. Effects of spin-nonflip collisions on spin dynamics are discussed for non-Poisson as well as Poisson processes. In unpolarized media, the time evolution of the muon spin in muonium is not influenced by spin-nonflip collisions, if the collision process is Poissonian. This seemingly obvious statement is not true anymore in non-Poissonian processes, i.e., it is necessary to specify both spin-flip and spin-nonflip rates to fully characterize spin dynamics

  7. Characterization of the local layer structure of a broad wall in a surface stabilized ferroelectric liquid crystal using synchrotron X-ray micro-diffraction

    International Nuclear Information System (INIS)

    Iida, Atsuo; Noma, Takashi; Miyata, Hirokatsu.

    1996-01-01

    The local layer structure of the broad wall of a zig-zag defect in a thin-surface stabilized ferroelectric liquid crystal cell was characterized using a synchrotron X-ray microbeam of less than 5 μm spatial resolution. By using a rocking curve measurement at the broad wall, multiple or broad peaks were observed between a pair of peaks due to a chevron structure. These new peaks are clear evidence of a modified pseudo-bookshelf structure at the wall. For 1.5 μm thick cells, a bookshelf layer is relatively flat, but is accompanied by small areas of inclined layer connecting the bookshelf and the chevron structures. For 10 μm thick cells, the pseudo-bookshelf structure bends or undulates both perpendicular and parallel to the rubbing direction. No appreciable change in the layer spacing was observed in the modified pseudo-bookshelf structure. The temperature dependence of the broad wall layer structure was also measured. (author)

  8. Characterization of the local layer structure of a broad wall in a surface stabilized ferroelectric liquid crystal using synchrotron X-ray micro-diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Iida, Atsuo [National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan); Noma, Takashi; Miyata, Hirokatsu

    1996-01-01

    The local layer structure of the broad wall of a zig-zag defect in a thin-surface stabilized ferroelectric liquid crystal cell was characterized using a synchrotron X-ray microbeam of less than 5 {mu}m spatial resolution. By using a rocking curve measurement at the broad wall, multiple or broad peaks were observed between a pair of peaks due to a chevron structure. These new peaks are clear evidence of a modified pseudo-bookshelf structure at the wall. For 1.5 {mu}m thick cells, a bookshelf layer is relatively flat, but is accompanied by small areas of inclined layer connecting the bookshelf and the chevron structures. For 10 {mu}m thick cells, the pseudo-bookshelf structure bends or undulates both perpendicular and parallel to the rubbing direction. No appreciable change in the layer spacing was observed in the modified pseudo-bookshelf structure. The temperature dependence of the broad wall layer structure was also measured. (author)

  9. Trajectory effects in multiply charged ion-surface interactions

    International Nuclear Information System (INIS)

    Lebius, H.; Huang, W.; Schuch, R.

    1999-01-01

    Ar ions of 4.3 keV q in were scattered at large angles (θ=75 degree sign ) from a clean oriented surface. By selecting Ar projectiles having a large ionization potential and by using a large scattering angle only ions scattered at the first atomic layer of the surface were detected. Scattered ion energy spectra show peaks of single scattering and double scattering of the Ar projectile ions from one or two surface Au atoms, and the distribution attributed to double collisions splits into two peaks when the scattering plane coincides with a crystallographic plane. Simulations with a MARLOWE code allowed for interpretation of the structure in the double collision peak by in-plane and zig-zag double collisions. Differences in the relative peak heights between the experiment and a MARLOWE simulation were partly explained by different neutralization probabilities with varying trajectories. Yield changes with increasing charge states show interesting possibilities for future experiments with highly charged ions

  10. Computational aspects of unsteady flows

    Science.gov (United States)

    Cebeci, T.; Carr, L. W.; Khattab, A. A.; Schimke, S. M.

    1985-01-01

    The calculation of unsteady flows and the development of numerical methods for solving unsteady boundary layer equations and their application to the flows around important configurations such as oscillating airfoils are presented. A brief review of recent work is provided with emphasis on the need for numerical methods which can overcome possible problems associated with flow reversal and separation. The zig-zag and characteristic box schemes are described in this context, and when embodied in a method which permits interaction between solutions of inviscid and viscous equations, the characteristic box scheme is shown to avoid the singularity associated with boundary layer equations and prescribed pressure gradient. Calculations were performed for a cylinder started impulsively from rest and oscillating airfoils. The results are presented and discussed. It is conlcuded that turbulence models based on an algebraic specification of eddy viscosity can be adequate, that location of translation is important to the calculation of the location of flow separation and, therefore, to the overall lift of an oscillating airfoil.

  11. Chemical mechanisms in mercury emission control technologies

    Energy Technology Data Exchange (ETDEWEB)

    Olson, E.S.; Laumb, J.D.; Benson, S.A.; Dunham, G.E.; Sharma, R.K.; Mibeck, B.A.; Miller, S.J.; Holmes, M.J.; Pavlish, J.H. [University of North Dakota, Energy and Environmental Research Center, Grand Forks, ND (United States)

    2003-05-01

    The emission of elemental mercury in the flue gas from coal-burning power plants is a major environmental concern. Control technologies utilizing activated carbon show promise and are currently under intense review. Oxidation and capture of elemental mercury on activated carbon was extensively investigated in a variety of flue gas atmospheres. Extensive parametric testing with individual and a variety of combinations and concentrations of reactive flue gas components and spectroscopic examination of the sulfur and chlorine forms present before and after breakthrough have led to an improved model to explain the kinetic and capacity results. The improved model delineates the independent Lewis acid oxidation site as well as a zig-zag carbene site on the carbon edge that performs as a Lewis base in reacting with both the oxidized mercury formed at the oxidation site and with the acidic flue gas components in competing reactions to form organochlorine, sulfinate, and sulfate ester moieties on the carbon edge.

  12. Visualizing band offsets and edge states in bilayer–monolayer transition metal dichalcogenides lateral heterojunction

    KAUST Repository

    Zhang, Chendong

    2016-01-18

    Semiconductor heterostructures are fundamental building blocks for many important device applications. The emergence of two-dimensional semiconductors opens up a new realm for creating heterostructures. As the bandgaps of transition metal dichalcogenides thin films have sensitive layer dependence, it is natural to create lateral heterojunctions (HJs) using the same materials with different thicknesses. Here we show the real space image of electronic structures across the bilayer–monolayer interface in MoSe2 and WSe2, using scanning tunnelling microscopy and spectroscopy. Most bilayer–monolayer HJs are found to have a zig-zag-orientated interface, and the band alignment of such atomically sharp HJs is of type-I with a well-defined interface mode that acts as a narrower-gap quantum wire. The ability to utilize such commonly existing thickness terraces as lateral HJs is a crucial addition to the tool set for device applications based on atomically thin transition metal dichalcogenides, with the advantage of easy and flexible implementation.

  13. Electrostatic mechanism of nucleosomal array folding revealed by computer simulation.

    Science.gov (United States)

    Sun, Jian; Zhang, Qing; Schlick, Tamar

    2005-06-07

    Although numerous experiments indicate that the chromatin fiber displays salt-dependent conformations, the associated molecular mechanism remains unclear. Here, we apply an irregular Discrete Surface Charge Optimization (DiSCO) model of the nucleosome with all histone tails incorporated to describe by Monte Carlo simulations salt-dependent rearrangements of a nucleosomal array with 12 nucleosomes. The ensemble of nucleosomal array conformations display salt-dependent condensation in good agreement with hydrodynamic measurements and suggest that the array adopts highly irregular 3D zig-zag conformations at high (physiological) salt concentrations and transitions into the extended "beads-on-a-string" conformation at low salt. Energy analyses indicate that the repulsion among linker DNA leads to this extended form, whereas internucleosome attraction drives the folding at high salt. The balance between these two contributions determines the salt-dependent condensation. Importantly, the internucleosome and linker DNA-nucleosome attractions require histone tails; we find that the H3 tails, in particular, are crucial for stabilizing the moderately folded fiber at physiological monovalent salt.

  14. Crystal structures and theoretical studies of polyphosphate LiZnP3O9 for nonlinear optical applications

    Science.gov (United States)

    Xie, Zhiqing; Su, Xin; Ding, Hanqin; Li, Hongyi

    2018-06-01

    Nonlinear optical materials have attracted worldwide attention owing to their wide range of applications, specially in the laser field. Phosphates with noncentrosymmetric structures are potential candidates for novel ultraviolet (UV)-NLO materials, because they usually display short UV cut-off edges. In this work, a polyphosphate, the LiZnP3O9 polyphosphate crystals were grown through spontaneous crystallization from high-temperature melts. It crystallizes in the orthorhombic space group P212121 with unit cell parameters a = 8.330(3) Å, b = 8.520(3) Å, c = 8.635(3) Å, and Z = 4. In the structure, all the P atoms are coordinated by four oxygen atoms forming the [PO4] tetrahedra and further connected to generate a zig-zag [PO3]∞ anionic framework. Thermal analysis, IR spectroscopy, UV-vis-NIR diffuse reflectance spectrum and powder second harmonic generation measurements are performed. In addition, the first-principles calculation was employed for better understanding the structure-property relationships of LiZnP3O9.

  15. Solvent induced synthesis, structure and properties of coordination polymers based on 5-hydroxyisophthalic acid as linker and 1,10-phenanthroline as auxiliary ligand

    Science.gov (United States)

    Kariem, Mukaddus; Yawer, Mohd; Sheikh, Haq Nawaz

    2015-11-01

    Three new coordination polymers [Mn(hip)(phen) (H2O)]n (1), [Co(hip)(phen) (H2O)]n (2), and [Cd(hip) (phen) (H2O)]n (3) (H2hip=5-hydroxyisophthalic acid; phen=1,10-phenanthroline) have been synthesized by solvo-hydrothermal method using diethyl formamide-water (DEF-H2O) as solvent system. Single-crystal X-ray diffraction analysis reveals that all three coordination polymers 1, 2 and 3 crystallize in monoclinic space group P2/n. Metal ions are inter-connected by hydroxyisophthalate anions forming zig-zag 1D chain. 1D chains are further inter-connected by hydrogen bonding and π-π stacking interactions leading to 3D supramolecular architecture. Hydrogen-bonding and π-π stacking provide thermal stability to polymers. Compounds 1 and 2 are paramagnetic at room temperature and variable temperature magnetic moment measurements revealed weak ferromagnetic interactions between metal ions at low temperature. Compound 3 exhibits excellent photoluminescence with large Stokes shift.

  16. A Molecular Dynamics of Cold Neutral Atoms Captured by Carbon Nanotube Under Electric Field and Thermal Effect as a Selective Atoms Sensor.

    Science.gov (United States)

    Santos, Elson C; Neto, Abel F G; Maneschy, Carlos E; Chen, James; Ramalho, Teodorico C; Neto, A M J C

    2015-05-01

    Here we analyzed several physical behaviors through computational simulation of systems consisting of a zig-zag type carbon nanotube and relaxed cold atoms (Rb, Au, Si and Ar). These atoms were chosen due to their different chemical properties. The atoms individually were relaxed on the outside of the nanotube during the simulations. Each system was found under the influence of a uniform electric field parallel to the carbon nanotube and under the thermal effect of the initial temperature at the simulations. Because of the electric field, the cold atoms orbited the carbon nanotube while increasing the initial temperature allowed the variation of the radius of the orbiting atoms. We calculated the following quantities: kinetic energy, potential energy and total energy and in situ temperature, molar entropy variation and average radius of the orbit of the atoms. Our data suggest that only the action of electric field is enough to generate the attractive potential and this system could be used as a selected atoms sensor.

  17. Drop of canistered spent fuel segments into a deep borehole and subsequent aerosol release

    International Nuclear Information System (INIS)

    Bantle, S.; Herbe, H.; Miu, J.

    1991-09-01

    The source term of the released aerosols is estimated. First, the number of failing canisters is calculated for the case of an axial symmetric canister (POLLUX) pile, and then, for the case of a 'zig-zag' pile, as found in reality. The weight-specific energy acting on the fuel - a measure for the degree of fuel fractioning - is determined from the acceleration acting on the pin segments. In the borehole prevails a steady-state flow pattern which is stimulated by the heat of the disposed waste canister, and is also influenced by the ventilation of the drift above the borehole. Based on this stationary flow pattern flow velocities are calculated by means of fluid mechanical methods. Further investigations deal with the unsteady case which occurs during and immediately after the canister drop as well as with the wake behind the canister. The most relevant result is that under the considered boundary conditions no release form the borehole into the repository is to be expected. (orig./HP) [de

  18. Parametric study on nonlinear vibration of composite truss core sandwich plate with internal resonance

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jia Nen; Liu, Jun [Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System, Tianjin University of Technology, Tianjin (China); Zhang, Wei; Yao, Ming Hui [College of Mechanical Engineering, Beijing University of Technology, Beijing (China); Sun, Min [School of Science, Tianjin Chengjian University, Tianjin (China)

    2016-09-15

    Nonlinear vibrations of carbon fiber reinforced composite sandwich plate with pyramidal truss core are investigated. The governing equation of motion for the sandwich plate is derived by using a Zig-Zag theory under consideration of geometrically nonlinear. The natural frequencies of sandwich plates with different dimensions are calculated and compared with those obtained from the classic laminated plate theory and Reddy's third-order shear deformation plate theory. The frequency responses and waveforms of the sandwich plate when 1:3 internal resonance occurs are obtained, and the characteristics of the internal resonance are discussed. The influences of layer number of face sheet, strut radius, core height and inclination angle on the nonlinear responses of the sandwich plate are analyzed. The results demonstrate that the strut radius and inclination angle mainly affect the resonance frequency band of the sandwich plate, and the layer number and core height not only influence the resonance frequency band but also significantly affect the response amplitude.

  19. Fermi Surface and Band Structure of (Ca,La)FeAs2 Superconductor from Angle-Resolved Photoemission Spectroscopy

    International Nuclear Information System (INIS)

    Liu Xu; Liu De-Fa; Zhao Lin; Guo Qi; Mu Qing-Ge; Chen Dong-Yun; Shen Bing; Yi He-Mian; Huang Jian-Wei; He Jun-Feng; Peng Ying-Ying; Liu Yan; He Shao-Long; Liu Guo-Dong; Dong Xiao-Li; Zhang Jun; Ren Zhi-An; Zhou Xing-Jiang; Chen Chuang-Tian; Xu Zu-Yan

    2013-01-01

    The (Ca,R)FeAs 2 (R=La, Pr, etc.) superconductors with a signature of superconductivity transition above 40 K possess a new kind of block layers that consist of zig-zag As chains. We report the electronic structure of the new (Ca,La)FeAs 2 superconductor investigated by both band structure calculations and high resolution angle-resolved photoemission spectroscopy measurements. Band structure calculations indicate that there are four hole-like bands around the zone center Γ(0,0) and two electron-like bands near the zone corner M(π, π) in CaFeAs 2 . In our angle-resolved photoemission measurements on (Ca 0.9 La 0.1 )FeAs 2 , we have observed three hole-like bands around the Γ point and one electron-like Fermi surface near the M(π, π) point. These results provide important information to compare and contrast with the electronic structure of other iron-based compounds in understanding the superconductivity mechanism in the iron-based superconductors. (express letter)

  20. Visualization of boundary layer separation and passive flow control on airfoils and bodies in wind-tunnel and in-flight experiments

    Directory of Open Access Journals (Sweden)

    Matejka Milan

    2012-04-01

    Full Text Available Infrared camera, Particle Image Velocimetry, smoke-wire, tuft filaments and oil-flow visualization techniques were used for wind-tunnel and in-flight investigation of boundary layer separation, both stall and separation bubbles, related to the low-Reynolds numbers transition mechanism. Airfoils of Wortmann FX66 series and FX66 series wing-fuselage interaction, as well as modern airfoils and their wing-fuselage geometry were subject to study. The presence of previously identified structures in the CFD modelling, such as horse-shoe vortices, was confirmed in the flow. Wind-tunnels and in-flight measurements on sailplanes were carried out and effect of passive flow control devices - vortex generators - was surveyed; namely counter-rotating vortex generators and Zig-zag type turbulators were applied. Separation suppression and consequent drag coefficient reduction of test aircrafts was reached. PIV investigation was further extended by Time-Resolved techniques. An important study on structure of the turbulent flow in the lower atmosphere, creating an environment of the soaring flight, was presented.

  1. Visualization of boundary layer separation and passive flow control on airfoils and bodies in wind-tunnel and in-flight experiments

    Science.gov (United States)

    Popelka, Lukas; Kuklova, Jana; Simurda, David; Souckova, Natalie; Matejka, Milan; Uruba, Vaclav

    2012-04-01

    Infrared camera, Particle Image Velocimetry, smoke-wire, tuft filaments and oil-flow visualization techniques were used for wind-tunnel and in-flight investigation of boundary layer separation, both stall and separation bubbles, related to the low-Reynolds numbers transition mechanism. Airfoils of Wortmann FX66 series and FX66 series wing-fuselage interaction, as well as modern airfoils and their wing-fuselage geometry were subject to study. The presence of previously identified structures in the CFD modelling, such as horse-shoe vortices, was confirmed in the flow. Wind-tunnels and in-flight measurements on sailplanes were carried out and effect of passive flow control devices - vortex generators - was surveyed; namely counter-rotating vortex generators and Zig-zag type turbulators were applied. Separation suppression and consequent drag coefficient reduction of test aircrafts was reached. PIV investigation was further extended by Time-Resolved techniques. An important study on structure of the turbulent flow in the lower atmosphere, creating an environment of the soaring flight, was presented.

  2. Neutron spin quantum precession using multilayer spin splitters and a phase-spin echo interferometer

    International Nuclear Information System (INIS)

    Ebisawa, Toru; Tasaki, Seiji; Kawai, Takeshi; Hino, Masahiro; Akiyoshi, Tsunekazu; Achiwa, Norio; Otake, Yoshie; Funahashi, Haruhiko.

    1996-01-01

    Neutron spin quantum precession by multilayer spin splitter has been demonstrated using a new spin interferometer. The multilayer spin splitter consists of a magnetic multilayer mirror on top, followed by a gap layer and a non magnetic multilayer mirror which are evaporated on a silicon substrate. Using the multilayer spin splitter, a polarized neutron wave in a magnetic field perpendicular to the polarization is split into two spin eigenstates with a phase shift in the direction of the magnetic field. The spin quantum precession is equal to the phase shift, which depends on the effective thickness of the gap layer. The demonstration experiments verify the multilayer spin splitter as a neutron spin precession device as well as the coherent superposition principle of the two spin eigenstates. We have developed a new phase-spin echo interferometer using the multilayer spin splitters. We present successful performance tests of the multilayer spin splitter and the phase-spin echo interferometer. (author)

  3. Phase dynamics of a Josephson junction ladder driven by modulated currents

    International Nuclear Information System (INIS)

    Kawaguchi, T.

    2011-01-01

    Phase dynamics of disordered Josephson junction ladders (JJLs) driven by external currents which are spatially and temporally modulated is studied using a numerical simulation based on a random field XY model. This model is considered theoretically as an effective model of JJLs with structural disorder in a magnetic field. The spatiotemporal modulation of external currents causes peculiar dynamical effects of phases in the system under certain conditions, such as the directed motion of phases and the mode-locking in the absence of dc currents. We clarify the details of effects of the spatiotemporal modulation on the phase dynamics.

  4. Spin drift and spin diffusion currents in semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Idrish Miah, M [Nanoscale Science and Technology Centre and School of Biomolecular and Physical Sciences, Griffith University, Nathan, Brisbane, QLD 4111 (Australia)], E-mail: m.miah@griffith.edu.au

    2008-09-15

    On the basis of a spin drift-diffusion model, we show how the spin current is composed and find that spin drift and spin diffusion contribute additively to the spin current, where the spin diffusion current decreases with electric field while the spin drift current increases, demonstrating that the extension of the spin diffusion length by a strong field does not result in a significant increase in spin current in semiconductors owing to the competing effect of the electric field on diffusion. We also find that there is a spin drift-diffusion crossover field for a process in which the drift and diffusion contribute equally to the spin current, which suggests a possible method of identifying whether the process for a given electric field is in the spin drift or spin diffusion regime. Spin drift-diffusion crossover fields for GaAs are calculated and are found to be quite small. We derive the relations between intrinsic spin diffusion length and the spin drift-diffusion crossover field of a semiconductor for different electron statistical regimes. The findings resulting from this investigation might be important for semiconductor spintronics.

  5. Spin drift and spin diffusion currents in semiconductors

    Directory of Open Access Journals (Sweden)

    M Idrish Miah

    2008-01-01

    Full Text Available On the basis of a spin drift-diffusion model, we show how the spin current is composed and find that spin drift and spin diffusion contribute additively to the spin current, where the spin diffusion current decreases with electric field while the spin drift current increases, demonstrating that the extension of the spin diffusion length by a strong field does not result in a significant increase in spin current in semiconductors owing to the competing effect of the electric field on diffusion. We also find that there is a spin drift-diffusion crossover field for a process in which the drift and diffusion contribute equally to the spin current, which suggests a possible method of identifying whether the process for a given electric field is in the spin drift or spin diffusion regime. Spin drift-diffusion crossover fields for GaAs are calculated and are found to be quite small. We derive the relations between intrinsic spin diffusion length and the spin drift-diffusion crossover field of a semiconductor for different electron statistical regimes. The findings resulting from this investigation might be important for semiconductor spintronics.

  6. Spin drift and spin diffusion currents in semiconductors

    International Nuclear Information System (INIS)

    Idrish Miah, M

    2008-01-01

    On the basis of a spin drift-diffusion model, we show how the spin current is composed and find that spin drift and spin diffusion contribute additively to the spin current, where the spin diffusion current decreases with electric field while the spin drift current increases, demonstrating that the extension of the spin diffusion length by a strong field does not result in a significant increase in spin current in semiconductors owing to the competing effect of the electric field on diffusion. We also find that there is a spin drift-diffusion crossover field for a process in which the drift and diffusion contribute equally to the spin current, which suggests a possible method of identifying whether the process for a given electric field is in the spin drift or spin diffusion regime. Spin drift-diffusion crossover fields for GaAs are calculated and are found to be quite small. We derive the relations between intrinsic spin diffusion length and the spin drift-diffusion crossover field of a semiconductor for different electron statistical regimes. The findings resulting from this investigation might be important for semiconductor spintronics.

  7. Towers and ladders: Infinite parameter symmetries in Kaluza-Klein theories

    International Nuclear Information System (INIS)

    Aulakh, C.S.

    1984-05-01

    We introduce a class of infinite dimensional algebras with a 'generalized loop structure' by considering the global symmetries of the four dimensional Lagrangian obtained by compactifying general relativity coupled to Yang-Mills in six dimensions down to M 4 xS 2 . The generalization to arbitrary dimensions is then obvious. We show by explicit construction that such algebras possess an infinite number of finite sub-algebras. Among which, for the six dimensional case, is so(1,3) realized on S 2 with vanishing Casimir invariants. This so(1,3) may be interpreted, in accord with a previous conjecture of Salam and Strathdee [Ann. Phys. 141, 316(1982)], as the 'ladder' symmetry for the Kaluza-Klein towers. (author)

  8. Studies toward brevisulcenal F via convergent strategies for marine ladder polyether synthesis.

    Science.gov (United States)

    Katcher, Matthew; Jamison, Timothy F

    2018-03-15

    Shortly after the initial isolation of marine ladder polyether natural products, biomimetic epoxide-opening cascade reactions were proposed as an efficient strategy for the synthesis of these compounds. However, difficulties in assembling the cascade precursors have limited the realization of these cascades. In this report, we describe strategies that provide convergent access to cascade precursors via regioselective allylation and efficient fragment coupling. We then investigate epoxide-opening cascades promoted by strong bases for the formation of fused tetrahydropyrans. These strategies are evaluated in the context of the synthesis of rings CDEFG of brevisulcenal F.

  9. Spin Polarization Oscillations without Spin Precession: Spin-Orbit Entangled Resonances in Quasi-One-Dimensional Spin Transport

    Directory of Open Access Journals (Sweden)

    D. H. Berman

    2014-03-01

    Full Text Available Resonant behavior involving spin-orbit entangled states occurs for spin transport along a narrow channel defined in a two-dimensional electron gas, including an apparent rapid relaxation of the spin polarization for special values of the channel width and applied magnetic field (so-called ballistic spin resonance. A fully quantum-mechanical theory for transport using multiple subbands of the one-dimensional system provides the dependence of the spin density on the applied magnetic field and channel width and position along the channel. We show how the spatially nonoscillating part of the spin density vanishes when the Zeeman energy matches the subband energy splittings. The resonance phenomenon persists in the presence of disorder.

  10. Effect of spin rotation coupling on spin transport

    International Nuclear Information System (INIS)

    Chowdhury, Debashree; Basu, B.

    2013-01-01

    We have studied the spin rotation coupling (SRC) as an ingredient to explain different spin-related issues. This special kind of coupling can play the role of a Dresselhaus like coupling in certain conditions. Consequently, one can control the spin splitting, induced by the Dresselhaus like term, which is unusual in a semiconductor heterostructure. Within this framework, we also study the renormalization of the spin-dependent electric field and spin current due to the k → ⋅p → perturbation, by taking into account the interband mixing in the rotating system. In this paper we predict the enhancement of the spin-dependent electric field resulting from the renormalized spin rotation coupling. The renormalization factor of the spin electric field is different from that of the SRC or Zeeman coupling. The effect of renormalized SRC on spin current and Berry curvature is also studied. Interestingly, in the presence of this SRC-induced SOC it is possible to describe spin splitting as well as spin galvanic effect in semiconductors. -- Highlights: •Studied effect of spin rotation coupling on the spin electric field, spin current and Berry curvature. •In the k → ⋅p → framework we study the renormalization of spin electric field and spin current. •For an inertial system we have discussed the spin splitting. •Expression for the Berry phase in the inertial system is discussed. •The inertial spin galvanic effect is studied

  11. Effect of spin rotation coupling on spin transport

    Energy Technology Data Exchange (ETDEWEB)

    Chowdhury, Debashree, E-mail: debashreephys@gmail.com; Basu, B., E-mail: sribbasu@gmail.com

    2013-12-15

    We have studied the spin rotation coupling (SRC) as an ingredient to explain different spin-related issues. This special kind of coupling can play the role of a Dresselhaus like coupling in certain conditions. Consequently, one can control the spin splitting, induced by the Dresselhaus like term, which is unusual in a semiconductor heterostructure. Within this framework, we also study the renormalization of the spin-dependent electric field and spin current due to the k{sup →}⋅p{sup →} perturbation, by taking into account the interband mixing in the rotating system. In this paper we predict the enhancement of the spin-dependent electric field resulting from the renormalized spin rotation coupling. The renormalization factor of the spin electric field is different from that of the SRC or Zeeman coupling. The effect of renormalized SRC on spin current and Berry curvature is also studied. Interestingly, in the presence of this SRC-induced SOC it is possible to describe spin splitting as well as spin galvanic effect in semiconductors. -- Highlights: •Studied effect of spin rotation coupling on the spin electric field, spin current and Berry curvature. •In the k{sup →}⋅p{sup →} framework we study the renormalization of spin electric field and spin current. •For an inertial system we have discussed the spin splitting. •Expression for the Berry phase in the inertial system is discussed. •The inertial spin galvanic effect is studied.

  12. Geometric Summary of the 9 Chip Ladder for the D0 Silicon Tracker

    International Nuclear Information System (INIS)

    Ratzmann, P.; Cooper, W.; Goloskie, D.; Kowalski, J.; Lipton, R.; Rapidis, P.; Serritella, C.

    1997-01-01

    Two hybrids types are required to accomodate the flipping of ladders within each bulkhead layer, in order to account for the pigtail routing. Left and right versions are shown below, following the definitions laid out by Mike Matulik. These drawings are not to proper scale in the sketches below. The dimensionally correct versions of the 9 chip hybrids are stored in DCS under drawing number 3823.112-MD-317803 for the lefthanded version, and 3823.112-MD-317804 for the right handed version. Handedness of the hybrids are designated as shown in the figures and table below. There are long and short versions of both the left and the right, for four total 9 chip hdi designs. The pigtail lengths of the long and short are shown in a table in the hybrid drawings which reside in DCS. The chamfer in the hybrid corners (N side) is placed in order to enable the hybrid to be glued to the beryllium substrate, whereas the rectangular cuttout on the same side is to allow direct gluing of a temperature sensor to the substrate metal. The oblong shape on the N side of both hybrids is a 'stay-clear' region (defined in the final drawings) where pressure will be applied to the hybrid during the second stage of ladder construction.

  13. Energy-efficient ZigBee-based wireless sensor network for track bicycle performance monitoring.

    Science.gov (United States)

    Gharghan, Sadik K; Nordin, Rosdiadee; Ismail, Mahamod

    2014-08-22

    In a wireless sensor network (WSN), saving power is a vital requirement. In this paper, a simple point-to-point bike WSN was considered. The data of bike parameters, speed and cadence, were monitored and transmitted via a wireless communication based on the ZigBee protocol. Since the bike parameters are monitored and transmitted on every bike wheel rotation, this means the sensor node does not sleep for a long time, causing power consumption to rise. Therefore, a newly proposed algorithm, known as the Redundancy and Converged Data (RCD) algorithm, was implemented for this application to put the sensor node into sleep mode while maintaining the performance measurements. This is achieved by minimizing the data packets transmitted as much as possible and fusing the data of speed and cadence by utilizing the correlation measurements between them to minimize the number of sensor nodes in the network to one node, which results in reduced power consumption, cost, and size, in addition to simpler hardware implementation. Execution of the proposed RCD algorithm shows that this approach can reduce the current consumption to 1.69 mA, and save 95% of the sensor node energy. Also, the comparison results with different wireless standard technologies demonstrate minimal current consumption in the sensor node.

  14. A Low Power Consumption Algorithm for Efficient Energy Consumption in ZigBee Motes.

    Science.gov (United States)

    Vaquerizo-Hdez, Daniel; Muñoz, Pablo; R-Moreno, María D; F Barrero, David

    2017-09-22

    Wireless Sensor Networks (WSNs) are becoming increasingly popular since they can gather information from different locations without wires. This advantage is exploited in applications such as robotic systems, telecare, domotic or smart cities, among others. To gain independence from the electricity grid, WSNs devices are equipped with batteries, therefore their operational time is determined by the time that the batteries can power on the device. As a consequence, engineers must consider low energy consumption as a critical objective to design WSNs. Several approaches can be taken to make efficient use of energy in WSNs, for instance low-duty-cycling sensor networks (LDC-WSN). Based on the LDC-WSNs, we present LOKA, a LOw power Konsumption Algorithm to minimize WSNs energy consumption using different power modes in a sensor mote. The contribution of the work is a novel algorithm called LOKA that implements two duty-cycling mechanisms using the end-device of the ZigBee protocol (of the Application Support Sublayer) and an external microcontroller (Cortex M0+) in order to minimize the energy consumption of a delay tolerant networking. Experiments show that using LOKA, the energy required by the sensor device is reduced to half with respect to the same sensor device without using LOKA.

  15. A Low Power Consumption Algorithm for Efficient Energy Consumption in ZigBee Motes

    Directory of Open Access Journals (Sweden)

    Daniel Vaquerizo-Hdez

    2017-09-01

    Full Text Available Wireless Sensor Networks (WSNs are becoming increasingly popular since they can gather information from different locations without wires. This advantage is exploited in applications such as robotic systems, telecare, domotic or smart cities, among others. To gain independence from the electricity grid, WSNs devices are equipped with batteries, therefore their operational time is determined by the time that the batteries can power on the device. As a consequence, engineers must consider low energy consumption as a critical objective to design WSNs. Several approaches can be taken to make efficient use of energy in WSNs, for instance low-duty-cycling sensor networks (LDC-WSN. Based on the LDC-WSNs, we present LOKA, a LOw power Konsumption Algorithm to minimize WSNs energy consumption using different power modes in a sensor mote. The contribution of the work is a novel algorithm called LOKA that implements two duty-cycling mechanisms using the end-device of the ZigBee protocol (of the Application Support Sublayer and an external microcontroller (Cortex M0+ in order to minimize the energy consumption of a delay tolerant networking. Experiments show that using LOKA, the energy required by the sensor device is reduced to half with respect to the same sensor device without using LOKA.

  16. Energy-Efficient ZigBee-Based Wireless Sensor Network for Track Bicycle Performance Monitoring

    Directory of Open Access Journals (Sweden)

    Sadik K. Gharghan

    2014-08-01

    Full Text Available In a wireless sensor network (WSN, saving power is a vital requirement. In this paper, a simple point-to-point bike WSN was considered. The data of bike parameters, speed and cadence, were monitored and transmitted via a wireless communication based on the ZigBee protocol. Since the bike parameters are monitored and transmitted on every bike wheel rotation, this means the sensor node does not sleep for a long time, causing power consumption to rise. Therefore, a newly proposed algorithm, known as the Redundancy and Converged Data (RCD algorithm, was implemented for this application to put the sensor node into sleep mode while maintaining the performance measurements. This is achieved by minimizing the data packets transmitted as much as possible and fusing the data of speed and cadence by utilizing the correlation measurements between them to minimize the number of sensor nodes in the network to one node, which results in reduced power consumption, cost, and size, in addition to simpler hardware implementation. Execution of the proposed RCD algorithm shows that this approach can reduce the current consumption to 1.69 mA, and save 95% of the sensor node energy. Also, the comparison results with different wireless standard technologies demonstrate minimal current consumption in the sensor node.

  17. Nuclear theory. 1998 progress report

    International Nuclear Information System (INIS)

    1998-01-01

    Summaries of progress made on the following topics are given: (1) nonresonant contributions to inelastic N→Δ(1232) parity violation; (2) neutron distribution effects in elastic nuclear parity violation; (3) Wilson RG for scalar-plus-fermion field theories at finite density; (4) Perturbation theory for spin ladders using angular momentum coupled bases; (5) mean-field theory for spin ladders using angular momentum density; (6) finite temperature renormalization group effective potentials for the linear Sigma model; (7) negative-parity baryon resonances from lattice QCD; (8) the N→Δ electromagnetic transition amplitudes from QCD sum rules; and (9) higher nucleon resonances in exclusive reactions (γ, πN) on nuclei

  18. Monitoring and classifying animal behavior using ZigBee-based mobile ad hoc wireless sensor networks and artificial neural networks

    DEFF Research Database (Denmark)

    S. Nadimi, Esmaeil; Nyholm Jørgensen, Rasmus; Blanes-Vidal, Victoria

    2012-01-01

    Animal welfare is an issue of great importance in modern food production systems. Because animal behavior provides reliable information about animal health and welfare, recent research has aimed at designing monitoring systems capable of measuring behavioral parameters and transforming them...... into their corresponding behavioral modes. However, network unreliability and high-energy consumption have limited the applicability of those systems. In this study, a 2.4-GHz ZigBee-based mobile ad hoc wireless sensor network (MANET) that is able to overcome those problems is presented. The designed MANET showed high...... communication reliability, low energy consumption and low packet loss rate (14.8%) due to the deployment of modern communication protocols (e.g. multi-hop communication and handshaking protocol). The measured behavioral parameters were transformed into the corresponding behavioral modes using a multilayer...

  19. Magneto-optical polarization rotation in a ladder-type atomic system for tunable offset locking

    Energy Technology Data Exchange (ETDEWEB)

    Parniak, Michał, E-mail: michal.parniak@fuw.edu.pl; Leszczyński, Adam; Wasilewski, Wojciech [Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw (Poland)

    2016-04-18

    We demonstrate an easily tunable locking scheme for stabilizing frequency-sum of two lasers on a two-photon ladder transition based on polarization rotation in warm rubidium vapors induced by magnetic field and circularly polarized drive field. Unprecedented tunability of the two-photon offset frequency is due to strong splitting and shifting of magnetic states in external field. In our experimental setup, we achieve two-photon detuning of up to 700 MHz.

  20. Superconducting states and depinning transitions of Josephson ladders

    International Nuclear Information System (INIS)

    Barahona, M.; Strogatz, S.H.; Orlando, T.P.

    1998-01-01

    We present analytical and numerical studies of pinned superconducting states of open-ended Josephson ladder arrays, neglecting inductances but taking edge effects into account. Treating the edge effects perturbatively, we find analytical approximations for three of these superconducting states emdash the no-vortex, fully frustrated, and single-vortex states emdash as functions of the dc bias current I and the frustration f. Bifurcation theory is used to derive formulas for the depinning currents and critical frustrations at which the superconducting states disappear or lose dynamical stability as I and f are varied. These results are combined to yield a zero-temperature stability diagram of the system with respect to I and f. To highlight the effects of the edges, we compare this dynamical stability diagram to the thermodynamic phase diagram for the infinite system where edges have been neglected. We briefly indicate how to extend our methods to include self-inductances. copyright 1998 The American Physical Society