Full hyperfine structure analysis of singly ionized molybdenum
Bouazza, Safa
2017-03-01
For a first time a parametric study of hyperfine structure of Mo II configuration levels is presented. The newly measured A and B hyperfine structure (hfs) constants values of Mo II 4d5, 4d45s and 4d35s2 configuration levels, for both 95 and 97 isotopes, using Fast-ion-beam laser-induced fluorescence spectroscopy [1] are gathered with other few data available in literature. A fitting procedure of an isolated set of these three lowest even-parity configuration levels has been performed by taking into account second-order of perturbation theory including the effects of closed shell-open shell excitations. Moreover the same study was done for Mo II odd-parity levels; for both parities two sets of fine structure parameters as well as the leading eigenvector percentages of levels and Landé-factor gJ, relevant for this paper are given. We present also predicted singlet, triplet and quintet positions of missing experimental levels up to 85000 cm-1. The single-electron hfs parameter values were extracted in their entirety for 97Mo II and for 95Mo II: for instance for 95Mo II, a4d01 =-133.37 MHz and a5p01 =-160.25 MHz for 4d45p; a4d01 =-140.84 MHz, a5p01 =-170.18 MHz and a5s10 =-2898 MHz for 4d35s5p; a5s10 =-2529 (2) MHz and a4d01 =-135.17 (0.44) MHz for the 4d45s. These parameter values were analysed and compared with diverse ab-initio calculations. We closed this work with giving predicted values of magnetic dipole and electric quadrupole hfs constants of all known levels, whose splitting are not yet measured.
Analysis of structure of hyperfine poly(3-hydroxybutyrate) fibers (PHB) for controlled drug delivery
Olkhov, A. A.; Kosenko, R. Yu; Markin, V. S.; Zykova, A. K.; Pantyukhov, P. V.; Karpova, S. G.; Iordanskii, A. L.
2017-12-01
Hyperfine fibers based on biodegradable poly (3-hydroxybutyrate) with encapsulated drug substance (dipyridamol) were obtained by using electrospinning method. Addition of dipyridamol has a significant effect on geometrical shape and structure of microfibers as well as total porosity of fibrous material. Observation of fibers using scanning electron microscopy (SEM) method showed that without or at lower dipyridamol content (structures did not practically form, and fiber’s shape became cylindrical. The totality of morphological and structural characteristics determined the rate of dipyridamol diffusive transports. The simplified model of drug desorption from fibrous matrix was presented. In current work it was showed that the rate-limiting stage of transport was the diffusion of dipyridamol in the bulk of cylindrical fibers.
Quantum Theory of Hyperfine Structure Transitions in Diatomic Molecules.
Klempt, E.; And Others
1979-01-01
Described is an advanced undergraduate laboratory experiment in which radio-frequency transitions between molecular hyperfine structure states may be observed. Aspects of the quantum theory applied to the analysis of this physical system, are discussed. (Authors/BT)
Spin-torsion effects in the hyperfine structure of methanol
Coudert, L. H.; Gutlé, C.; Huet, T. R.; Grabow, J.-U.; Levshakov, S. A.
2015-07-01
The magnetic hyperfine structure of the non-rigid methanol molecule is investigated experimentally and theoretically. 12 hyperfine patterns are recorded using molecular beam microwave spectrometers. These patterns, along with previously recorded ones, are analyzed in an attempt to evidence the effects of the magnetic spin-torsion coupling due to the large amplitude internal rotation of the methyl group [J. E. M. Heuvel and A. Dymanus, J. Mol. Spectrosc. 47, 363 (1973)]. The theoretical approach setup to analyze the observed data accounts for this spin-torsion in addition to the familiar magnetic spin-rotation and spin-spin interactions. The theoretical approach relies on symmetry considerations to build a hyperfine coupling Hamiltonian and spin-rotation-torsion wavefunctions compatible with the Pauli exclusion principle. Although all experimental hyperfine patterns are not fully resolved, the line position analysis yields values for several parameters including one describing the spin-torsion coupling.
Hyperfine structure studies with the COMPLIS facility
Crawford, J E; Le Blanc, F; Lunney, M D; Obert, J; Oms, J; Putaux, J C; Roussière, B; Sauvage, J; Zemlyanoi, S G; Verney, D; Pinard, J; Cabaret, L A; Duong, H T; Huber, G; Krieg, M; Sebastian, V; Girod, M; Peru, S; Genevey, J; Ibrahim, F; Lettry, Jacques
1998-01-01
COMPLIS is an experimental facility designed to carry out spectroscopic studies on radioisotopes produced by disintegration of elements available at CERN's Booster-ISOLDE on-line isotope separator. During recent series of experimental runs, hyperfine structure measurements have yielded information on nuclear moments and deformations of platinum and iridium isotopes, For the first time, population by alpha -decay from Hg was exploited to investigate /sup 178/-/sup 181/Pt-the most neutron-deficient Pt isotopes yet studied. Successful measurements have recently been carried out on /sup 182-189/Ir. (10 refs).
Measurement of hyperfine structure and isotope shifts in Gd II
Del Papa, Dylan F.; Rose, Christopher D. M.; Rosner, S. David; Holt, Richard A.
2017-07-01
We have applied fast-ion-beam laser-fluorescence spectroscopy to measure the isotope shifts of 73 optical transitions in the wavelength range 421.5-455.8 nm and the hyperfine structures of 35 even parity and 33 odd parity levels in Gd II. Many of the isotope shifts and hyperfine structure measurements are the first for these transitions and levels. These atomic data can be used to correct for saturation and blending in the analysis of stellar spectra to determine chemical abundances. As a result, they have an important impact on studies of the history of nucleosynthesis in the Universe and on the use of photospheric abundance anomalies in Chemically Peculiar stars to infer indirect information about stellar interiors.
Hyperfine structure and isotope shift study in singly ionized lead
Wąsowicz, T. J.; Drozdowski, R.; Kwela, J.
2005-12-01
Hyperfine structure and isotope shifts in five optical transitions: 424.5 nm (6s^25f ^2textrm{F}_{7/2} 6s^26d^2 textrm{D}_{5/2}), 537.2 nm (6s^25f ^2textrm{F}_{7/2} 6s6p^2 ^4textrm{P}_{5/2}), 554.5 nm (6s^27d ^2textrm{D}_{5/2} 6s^27p ^2textrm{P}_{3/2}), 560.9 nm (6s^27p^2 textrm{P}_{3/2} 6s^27s ^2textrm{S}_{1/2}) and 666.0 nm (6s^27p ^2textrm{P}_{1/2} 6s^27s ^2textrm{S}_{1/2}) of Pb II have been measured. As a light source the discharge tube was used. The hyperfine structure measurements were performed using metallic isotope 207Pb. For isotope shifts measurements natural lead was used. The high resolution spectral apparatus consisted of a silver coated Fabry-Perot etalon and a grating spectrograph combined with a CCD camera used as a detector. In the analysis of the spectra a computer simulation technique was used. The hyperfine structure observations yielded the splitting constants A for seven levels of Pb II. The isotope shift studies enabled to separate the mass and the field shifts and to determine values of changes of the mean square nuclear charge radii.
Hyperfine structure of S-states of muonic tritium
Directory of Open Access Journals (Sweden)
Martynenko F.A.
2017-01-01
Full Text Available On the basis of quasipotential method in quantum electrodynamics we carry out a precise calculation of hyperfine splitting of S-states in muonic tritium. The one-loop and two-loop vacuum polarization corrections, relativistic effects, nuclear structure corrections in first and second orders of perturbation theory are taken into account. The contributions to hyperfine structure are obtained in integral form and calculated analytically and numerically. Obtained results for hyperfine splitting can be used for a comparison with future experimental data of CREMA collaboration.
Measurement of the hyperfine structure of antihydrogen in a beam
Widmann, E.; Juhasz, B.; Malbrunot, C.; Massiczek, O.; Sauerzopf, C.; Suzuki, K.; Wunschek, B.; Zmeskal, J.; Federmann, S.; Kuroda, N.; Ulmer, S.; Yamazaki, Y.
2013-01-01
A measurement of the hyperfine structure of antihydrogen promises one of the best tests of CPT symmetry. We describe an experiment planned at the Antiproton Decelerator of CERN to measure this quantity in a beam of slow antihydrogen atoms.
Lamb shifts and hyperfine structure in 6Li+ and 7Li+: Theory and experiment
DEFF Research Database (Denmark)
Riis, E.; Sinclair, A. G.; Poulsen, Ove
1994-01-01
High-precision laser-resonance measurements accurate to +/-0.5 MHz, or better are reported for transitions among the 1s2s S-3(1)-1s2p P-3(J) hyperfine manifolds for each of J = 0, 1, and 2 in both Li-6(+) and Li-7(+). A detailed analysis of hyperfine structure is performed for both the S and P st...
Hadronic deuteron polarizability contribution the hyperfine structure in muonic deuterium
Directory of Open Access Journals (Sweden)
Eskin A.V.
2017-01-01
Full Text Available The calculation of the contribution to the polarizability of the nucleus to hyperfine structure of muonic hydrogen is carried out within the unitary isobar model and on the basis of experimental data on the structure functions of deep inelastic lepton-proton and lepton-deuteron scattering. The calculation of virtual absorption cross sections of transversely and longitudinally polarized photons by nucleons in the resonance region is performed in the framework of the program MAID.
Measurements of isotope shifts and hyperfine structure in Ti II
Energy Technology Data Exchange (ETDEWEB)
Nouri, Z; Rosner, S D; Holt, R A [Department of Physics and Astronomy, University of Western Ontario, London, ON N6A 3K7 (Canada); Li, R [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6 T 2A3 (Canada); Scholl, T J, E-mail: rholt@uwo.c [Department of Medical Biophysics, University of Western Ontario, London, ON N6A 5C1 (Canada)
2010-06-01
We have applied fast-ion-beam laser-fluorescence spectroscopy to measure the isotope shifts of 38 transitions in the wavelength range 429-457 nm and the hyperfine structures (hfs) of 22 levels in Ti II. The isotope shift and hfs measurements are the first for these transitions and levels. These atomic data are essential for astrophysical studies of chemical abundances, allowing correction for saturation and the effects of blended lines.
Theoretical study of hyperfine structure constants of Ga isotopes
Wang, Q. M.; Li, J. G.; Fritzsche, S.; Godefroid, M.; Chang, Z. W.; Dong, C. Z.
2012-11-01
The hyperfine structure constants for the ground 4s24p 2P°3/2 and lowest excited states 4s25s 2S1/2 of 71Ga are calculated using the GRASP2K package based on the multi-configuration Dirac-Hartree-Fock method. Furthermore, the magnetic dipole (μ) and the electric quadrupole (Q) moments of the Ga isotopes from 67Ga to 81Ga are derived.
Calculation of hyperfine structure constants of small molecules using ...
Indian Academy of Sciences (India)
The Z-vector method in the relativistic coupled-cluster framework is employed to calculate the parallel and perpendicular components of the magnetic hyperfine structure constant of a few small alkaline earth hydrides (BeH, MgH, and CaH) and fluorides (MgF and CaF). We have compared our Z-vector results with the values ...
Deuterium hyperfine structure in interstellar C3HD
Bell, M. B.; Watson, J. K.; Feldman, P. A.; Matthews, H. E.; Madden, S. C.; Irvine, W. M.
1987-01-01
The deuterium nuclear quadrupole hyperfine structure of the transition 1(10)-1(01) of the ring molecule cyclopropenylidene-d1 (C3HD) has been observed in emission from interstellar molecular clouds. The narrowest linewidths (approximately 7 kHz) so far observed are in the cloud L1498. The derived D coupling constants Xzz = 186.9(1.4) kHz, eta=0.063(18) agree well with correlations based on other molecules.
Hyperfine Structure Measurements of Antiprotonic $^3$He using Microwave Spectroscopy
Friedreich, Susanne
The goal of this project was to measure the hyperfine structure of $\\overline{\\text{p}}^3$He$^+$ using the technique of laser-microwave-laser spectroscopy. Antiprotonic helium ($\\overline{\\text{p}}$He$^+$) is a neutral exotic atom, consisting of a helium nucleus, an electron and an antiproton. The interactions of the angular momenta of its constituents cause a hyperfine splitting ({HFS}) within the energy states of this new atom. The 3\\% of formed antiprotonic helium atoms which remain in a metastable, radiative decay-dominated state have a lifetime of about 1-3~$\\mu$s. This time window is used to do spectroscopic studies. The hyperfine structure of $\\overline{\\text{p}}^4$He$^+$ was already extensively investigated before. From these measurements the spin magnetic moment of the antiproton can be determined. A comparison of the result to the proton magnetic moment provides a test of {CPT} invariance. Due to its higher complexity the new exotic three-body system of $\\overline{\\text{p}}^3$He$^+$ is a cross-check...
Hyperfine Structure and Isotope Shifts in Dy II
Directory of Open Access Journals (Sweden)
Dylan F. Del Papa
2017-01-01
Full Text Available Using fast-ion-beam laser-fluorescence spectroscopy (FIBLAS, we have measured the hyperfine structure (hfs of 14 levels and an additional four transitions in Dy II and the isotope shifts (IS of 12 transitions in the wavelength range of 422–460 nm. These are the first precision measurements of this kind in Dy II. Along with hfs and IS, new undocumented transitions were discovered within 3 GHz of the targeted transitions. These atomic data are essential for astrophysical studies of chemical abundances, allowing correction for saturation and the effects of blended lines. Lanthanide abundances are important in diffusion modeling of stellar interiors, and in the mechanisms and history of nucleosynthesis in the universe. Hfs and IS also play an important role in the classification of energy levels, and provide a benchmark for theoretical atomic structure calculations.
Improved Study of the Antiprotonic Helium Hyperfine Structure
Pask, T.; Dax, A.; Hayano, R.S.; Hori, M.; Horvath, D.; Juhasz, B.; Malbrunot, C.; Marton, J.; Ono, N.; Suzuki, K.; Zmeskal, J.; Widmann, E.
2008-01-01
We report the initial results from a systematic study of the hyperfine (HF) structure of antiprotonic helium (n,l) = (37,~35) carried out at the Antiproton Decelerator (AD) at CERN. We performed a laser-microwave-laser resonance spectroscopy using a continuous wave (cw) pulse-amplified laser system and microwave cavity to measure the HF transition frequencies. Improvements in the spectral linewidth and stability of our laser system have increased the precision of these measurements by a factor of five and reduced the line width by a factor of three compared to our previous results. A comparison of the experimentally measured transition frequencies with three body QED calculations can be used to determine the antiproton spin magnetic moment, leading towards a test of CPT invariance.
Fine- and hyperfine structure investigations of even configuration system of atomic terbium
Stefanska, D.; Elantkowska, M.; Ruczkowski, J.; Furmann, B.
2017-03-01
In this work a parametric study of the fine structure (fs) and the hyperfine structure (hfs) for the even-parity configurations of atomic terbium (Tb I) is presented, based in considerable part on the new experimental results. Measurements on 134 spectral lines were performed by laser induced fluorescence (LIF) in a hollow cathode discharge lamp; on this basis, the hyperfine structure constants A and B were determined for 52 even-parity levels belonging to the configurations 4f85d6s2, 4f85d26s or 4f96s6p; in all the cases those levels were involved in the transitions investigated as the lower levels. For 40 levels the hfs was examined for the first time, and for the remaining 12 levels the new measurements supplement our earlier results. As a by-product, also preliminary values of the hfs constants for 84 odd-parity levels were determined (the investigations of the odd-parity levels system in the terbium atom are still in progress). This huge amount of new experimental data, supplemented by our earlier published results, were considered for the fine and hyperfine structure analysis. A multi-configuration fit of 7 configurations was performed, taking into account second-order of perturbation theory, including the effects of closed shell-open shell excitations. Predicted values of the level energies, as well as of magnetic dipole and electric quadrupole hyperfine structure constants A and B, are quoted in cases when no experimental values are available. By combining our experimental data with our own semi-empirical procedure it was possible to identify correctly the lower and upper level of the line 544.1440 nm measured by Childs with the use of the atomic-beam laser-rf double-resonance technique (Childs, J Opt Soc Am B 9;1992:191-6).
Proton structure in the hyperfine splitting of muonic hydrogen
Hagelstein, Franziska; Pascalutsa, Vladimir
2015-01-01
We present the leading-order prediction of baryon chiral perturbation theory for the proton polarizability contribution to the 2S hyperfine splitting in muonic hydrogen, and compare with the results of dispersive calculations.
Elantkowska, Magdalena; Ruczkowski, Jarosław; Sikorski, Andrzej; Dembczyński, Jerzy
2017-11-01
A parametric analysis of the hyperfine structure (hfs) for the even parity configurations of atomic terbium (Tb I) is presented in this work. We introduce the complete set of 4fN-core states in our high-performance computing (HPC) calculations. For calculations of the huge hyperfine structure matrix, requiring approximately 5000 hours when run on a single CPU, we propose the methods utilizing a personal computer cluster or, alternatively a cluster of Microsoft Azure virtual machines (VM). These methods give a factor 12 performance boost, enabling the calculations to complete in an acceptable time.
ISOTROPIC INELASTIC COLLISIONS IN A MULTITERM ATOM WITH HYPERFINE STRUCTURE
Energy Technology Data Exchange (ETDEWEB)
Belluzzi, Luca [Istituto Ricerche Solari Locarno, CH-6605 Locarno Monti (Switzerland); Landi Degl’Innocenti, Egidio [Dipartimento di Fisica e Astronomia, Università di Firenze, I-50125 Firenze (Italy); Bueno, Javier Trujillo [Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife (Spain)
2015-10-10
A correct modeling of the scattering polarization profiles observed in some spectral lines of diagnostic interest, the sodium doublet being one of the most important examples, requires taking hyperfine structure (HFS) and quantum interference between different J-levels into account. An atomic model suitable for taking these physical ingredients into account is the so-called multiterm atom with HFS. In this work, we introduce and study the transfer and relaxation rates due to isotropic inelastic collisions with electrons, which enter the statistical equilibrium equations (SEE) for the atomic density matrix of this atomic model. Under the hypothesis that the electron–atom interaction is described by a dipolar operator, we provide useful relations between the rates describing the transfer and relaxation of quantum interference between different levels (whose numerical values are in most cases unknown) and the usual rates for the atomic level populations, for which experimental data and/or approximate theoretical expressions are generally available. For the particular case of a two-term atom with HFS, we present an analytical solution of the SEE for the spherical statistical tensors of the upper term, including both radiative and collisional processes, and we derive the expression of the emission coefficient in the four Stokes parameters. Finally, an illustrative application to the Na i D{sub 1} and D{sub 2} lines is presented.
Hyperfine structure and g-factor measurements in ion traps
Knab, H.; Knöll, K. H.; Arbes, F.; Becker, O.; Werth, G.
1992-10-01
We report about measurements on ground-state hyperfine splitting constants of stable Eu+ isotopes in radio frequency ion traps and experiments on the electronic g-factor of Ba+ in a Penning trap. From the precision of both measurements, which ranges between 3·10-6 and 5·10-7, we conclude that precise determination of the differential Bohr-Weisskopf effect in chains of isotopes will be possible in the near future.
Hyperfine structure of the hydroxyl free radical (OH) in electric and magnetic fields
Maeda, Kenji; Wall, Michael L.; Carr, Lincoln D.
2015-05-01
We investigate single-particle energy spectra of the hydroxyl free radical (OH) in the lowest electronic and rovibrational level under combined static electric and magnetic fields, as an example of heteronuclear polar diatomic molecules. In addition to the fine-structure interactions, the hyperfine interactions and centrifugal distortion effects are taken into account to yield the zero-field spectrum of the lowest 2Π3 / 2 manifold to an accuracy of less than 2kHz. We also examine level crossings and repulsions in the hyperfine structure induced by applied electric and magnetic fields. Compared to previous work, we found more than 10 percent reduction of the magnetic fields at level repulsions in the Zeeman spectrum subjected to a perpendicular electric field. In addition, we find new level repulsions, which we call Stark-induced hyperfine level repulsions, that require both an electric field and hyperfine structure. It is important to take into account hyperfine structure when we investigate physics of OH molecules at micro-Kelvin temperatures and below. This research was supported in part by AFOSR Grant No.FA9550-11-1-0224 and by the NSF under Grants PHY-1207881 and NSF PHY-1125915. We appreciate the Aspen Center for Physics, supported in part by the NSF Grant No.1066293, for hospitality.
The Theory of ESR Hyperfine-Structure Narrowing as Applied to Wide-Gap Semimagnetic Semiconductors
Aliev; Tagirov; Tagiev
1996-11-01
The theory of ESR hyperfine-structure exchange narrowing is developed. The kinetic equations describing the nonequilibrium magnetization dynamics of hyperfine components of ESR spectra are derived by using the nonequilibrium statistical-operator method. Numerical solution of these general equations is applied to the simulation of the experimental spectra of (Cd, Mn)Te crystals with a Mn2+ ion content of between 0.05 and 0.5%. The hyperfine-splitting constant, homogeneous ESR linewidth, and mean-square value of the exchange fluctuation frequency are obtained from the fitting of the spectra for different concentrations of manganese ions. The concentration dependence of the latter quantity is discussed in relation to the spatial dependence of magnetic-ion exchange interaction and the gap value in the band structure of semimagnetic semiconductors.
Measurement of hyperfine structure in the $\\rm D_1$ line of $^{87}$Rb
Datar, Durgesh; Ananthamurthy, Sharath; Natarajan, Vasant
2016-01-01
This work reports a new measurement of the hyperfine structure constant of the $\\rm D_1 $ line in $ \\rm ^{87}Rb $ through precision laser spectroscopy. In a departure from methods that rely on locking the laser on the transitions of interest, the technique reported here relies on scanning around the transition. This is carried out so as to overcome potential frequency shifts caused by various noise sources including electronic noise and thermal fluctuations. The value of the hyperfine constant reported here is $ A = 408.29(25) $ MHz, which is in variance from an earlier value reported from our lab but is consistent with other recent measurements.
Energy Technology Data Exchange (ETDEWEB)
Schroeder, L. [Deutsches Krebsforschungszentrum, Heidelberg (Germany). Medizinische Physik in der Radiologie; California Univ., Berkeley, CA (United States). Dept. of Chemistry; Lawrence Berkeley National Lab., Berkeley, CA (United States). Dept. of Chemistry
2007-07-01
The hyperfine interaction of two spins is a well studied effect in atomic systems. Magnetic resonance experiments demonstrate that the detectable dipole transitions are determined by the magnetic moments of the constituents and the external magnetic field. Transferring the corresponding quantum mechanics to molecular bound nuclear spins allows for precise prediction of NMR spectra obtained from metabolites in human tissue. This molecular hyperfine structure has been neglected so far in in vivo NMR spectroscopy but contains useful information, especially when studying molecular dynamics. This contribution represents a review of the concept of applying the Breit-Rabi formalism to coupled nuclear spins and discusses the immobilization of different metabolites in anisotropic tissue revealed by 1H NMR spectra of carnosine, phosphocreatine and taurine. Comparison of atomic and molecular spin systems allows for statements on the biological constraints for direct spin-spin interactions. Moreover, the relevance of hyperfine effects on the line shapes of multiplets of indirectly-coupled spin systems with more than two constituents can be predicted by analyzing quantum mechanical parameters. As an example, the superposition of eigenstates of the AMX system of adenosine 5'-triphosphate and its application for better quantification of 31P-NMR spectra will be discussed. (orig.)
Khan, Shamim; Gamper, Bettina; Iqbal, S. Tanweer; Windholz, Laurentius
2011-05-01
The electronic ground state configuration of praseodymium 59Pr141 is [Xe] 4f3 6s2 , with ground state level 4I9 / 2 . Our research is mainly devoted to find previously unknown energy levels by the investigation of spectral lines on the basis of their hyperfine (hf) structure. In a hollow cathode discharge lamp, praseodymium atoms and ions in ground and excited states are excited to high lying states by laser light. The laser induced fluorescence (LIF) signal is then recorded using lock-in detection techniques. From the recorded hyperfine structure we determine J-values and hyperfine constants A of the combining levels. This information, together with excitation and fluorescence wavelengths, allows us to find the energies of the involved new levels. Up to now we have discovered a large number of previously unknown energy levels with various angular momentum values. We present here the characteristic data (energy, parity, angular momentum J and magnetic hyperfine constant A) of ca. 40, until now unknown energy levels.
Structural properties and hyperfine characterization of Sn-substituted goethites
Energy Technology Data Exchange (ETDEWEB)
Larralde, A.L. [INQUIMAE, Departamento de Quimica Inorganica, Analitica y Quimica Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (Argentina); Ramos, C.P. [Departamento de Fisica de la Materia Condensada, GIyA - CAC - CNEA, Av. Gral. Paz 1499 (1650), San Martin, Bs. As. (Argentina); Arcondo, B. [Departamento de Fisica, Facultad de Ingenieria, Universidad de Buenos Aires, Av. Paseo Colon 850 (C1063ACV), Bs. As. (Argentina); Tufo, A.E. [INQUIMAE, Departamento de Quimica Inorganica, Analitica y Quimica Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (Argentina); Saragovi, C. [Departamento de Fisica de la Materia Condensada, GIyA - CAC - CNEA, Av. Gral. Paz 1499 (1650), San Martin, Bs. As. (Argentina); Sileo, E.E., E-mail: sileo@qi.fcen.uba.ar [INQUIMAE, Departamento de Quimica Inorganica, Analitica y Quimica Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (Argentina)
2012-04-16
Highlights: Black-Right-Pointing-Pointer Pure and tin-doped goethites were synthesized from Sn(II) solutions at ambient pressure and 70 Degree-Sign C. Black-Right-Pointing-Pointer The Rietveld refinement of PXRD data indicated that Sn partially substituted the Fe(III) ions. Black-Right-Pointing-Pointer The substitution provoked unit cell expansion, and a distortion of the coordination polyhedron. Black-Right-Pointing-Pointer {sup 119}Sn Moessbauer spectroscopy revealed that Sn(II) is incorporated as Sn(IV). Black-Right-Pointing-Pointer {sup 57}Fe Moessbauer spectroscopy showed a lower magnetic coupling as tin concentration increased. - Abstract: Tin-doped goethites obtained by a simple method at ambient pressure and 70 Degree-Sign C were characterized by inductively coupled plasma atomic emission spectrometry, scanning electron microscopy, Rietveld refinement of powder X-ray diffraction data, and {sup 57}Fe and {sup 119}Sn Moessbauer spectroscopy. The particles size and the length to width ratios decreased with tin-doping. Sn partially substituted the Fe(III) ions provoking unit cell expansion and increasing the crystallinity of the particles with enlarged domains that grow in the perpendicular and parallel directions to the anisotropic broadening (1 1 1) axis. Intermetallic E, E Prime and DC distances also change although the variations are not monotonous, indicating different variations in the coordination polyhedron. In general, the Sn-substituted samples present larger intermetallic distances than pure goethite, and the greatest change is shown in the E Prime distance which coincides with the c-parameter. {sup 119}Sn Moessbauer spectroscopy revealed that Sn(II) is incorporated as Sn(IV) in the samples. On the other hand, Fe(II) presence was not detected by {sup 57}Fe Moessbauer spectroscopy, suggesting the existence of vacancies in the Sn-doped samples. A lower magnetic coupling is also evidenced from the average magnetic hyperfine field values obtained as tin
Wavelengths, energy levels and hyperfine structure of Mn II and Sc II.
Nave, Gillian; Pickering, Juliet C.; Townley-Smith, Keeley I. M.; Hala, .
2015-08-01
For many decades, the Atomic Spectroscopy Groups at the National Institute of Standards and Technology (NIST) and Imperial College London (ICL) have measured atomic data of astronomical interest. Our spectrometers include Fourier transform (FT) spectrometers at NIST and ICL covering the region 1350 Å to 5.5 μm and a 10.7-m grating spectrometer at NIST covering wavelengths from 300 - 5000 Å. Sources for these spectra include high-current continuous and pulsed hollow cathode (HCL) lamps, Penning discharges, and sliding spark discharges. Recent work has focused on the measurement and analysis of wavelengths, energy levels, and hyperfine structure (HFS) constants for iron-group elements. The analysis of FT spectra of Cr I, Mn I, and Mn II is being led by ICL and is described in a companion poster [1]. Current work being led by NIST includes the analysis of HFS in Mn II, analysis of Mn II in the vacuum ultraviolet, and a comprehensive analysis of Sc II.Comprehensive HFS constants for Mn II are needed for the interpretation of stellar spectra and incorrect abundances may be obtained when HFS is omitted. Holt et al. [2] have measured HFS constants for 59 levels of Mn II using laser spectroscopy. We used FT spectra of Mn/Ni and Mn/Cu HCLs covering wavelength ranges from 1350 Å to 5.4 μm to confirm 26 of the A constants of Holt et al. and obtain values for roughly 40 additional levels. We aim to obtain HFS constants for the majority of lines showing significant HFS that are observed in chemically-peculiar stars.Spectra of Sc HCLs have been recorded from 1800 - 6700 Å using a vacuum ultraviolet FT spectrometer at NIST. Additional measurements to cover wavelengths above 6700 Å and below 1800 Å are in progress. The spectra are being analyzed by NIST and Alighar Muslim University, India in order to derive improved wavelengths, energy levels, and hyperfine structure parameters.This work was partially supported by NASA, the STFC and PPARC (UK), the Royal Society of the UK
Towards isotope shift and hyperfine structure measurements of the element nobelium
Energy Technology Data Exchange (ETDEWEB)
Chhetri, Premaditya; Lautenschlaeger, Felix; Walther, Thomas [Institut fuer Angewandte Physik, TU Darmstadt, D-64289 Darmstadt (Germany); Laatiaoui, Mustapha [Helmholtz Institut Mainz, D-55099 Mainz (Germany); Block, Michael; Hessberger, Fritz-Peter [Helmholtz Institut Mainz, D-55099 Mainz (Germany); GSI, D-64291 Darmstadt (Germany); Lauth, Werner; Backe, Hartmut [Institut fuer Kernphysik, JGU Mainz, D-55122 Mainz (Germany); Kunz, Peter [TRIUMF, D-V6T2A3 Vancouver (Canada)
2014-07-01
Laser spectroscopy on the heaviest elements is of great interest as it allows the study of the evolution of relativistic effects on their atomic structure. In our experiment we exploit the Radiation Detected Resonance Ionization Spectroscopy technique and use excimer-laser pumped dye lasers to search for the first time the {sup 1}P{sub 1} level in {sup 254}No. Etalons will be used in the forthcoming experiments at GSI, Darmstadt, to narrow down the bandwidth of the dye lasers to 0.04 cm{sup -1}, for the determination of the isotope shift and hyperfine splitting of {sup 253,} {sup 255}No. In this talk results from preparatory hyperfine structure studies in nat. ytterbium and the perspectives for future experiments of the heaviest elements are discussed.
Electronic structure and hyperfine parameters of substitutional Al and P impurities in silica
DEFF Research Database (Denmark)
Lægsgaard, Jesper; Stokbro, Kurt
2002-01-01
The electronic structure of substitutional Al and P impurities in silica is investigated using supercell calculations within the framework of density functional theory (DFT). Evaluation of hyperfine matrices for the magnetic nuclei facilitates comparison to experimental data. It is found that the......The electronic structure of substitutional Al and P impurities in silica is investigated using supercell calculations within the framework of density functional theory (DFT). Evaluation of hyperfine matrices for the magnetic nuclei facilitates comparison to experimental data. It is found......, there is an "asymmetry" between electrons and holes in the electronic states of the silica network: The hole present at the Al impurity goes into a nonbonding O orbital while the extra electron present at the P impurity goes into a P-O antibonding state....
Pujari, Minakhi
the study of the hyperfine properties of the low spin nitrosyl-hemoglobin system. This system was of major interest in the present work to study the influence of the changes of pH and addition of inositol hexaphosphate on its structure and infer corresponding effects for the deoxy-hemoglobin system. Our results for nitrosyl-hemoglobin provide theoretical support to the model of essential weakening of the Fe- N3 bond that had been proposed in the literature to explain the observed change from nine- to three-line pattern in Electron Paramagnetic Resonance spectra associated with the transition of nitrosyl-hemoglobin from the R (relaxed, Oxy) form to the T(tense, Deoxy) form under the influence of inositol hexaphosphate or changes in pH. At low pH, it is associated with the T state and at high pH, it is associated with the R state. The analysis of Nuclear Quadrupole Coupling Constants of 14NNO and N314 shows that the latter is very sensitive to protonation and deprotonation of Npros. The magnetic hyperfine constants for 57Fe are in reasonably good agreement with experimental Mössbauer results in nitrosyl-hemoglobin. The energies of the free imidazole and nitrosyl-hemoglobin in the R and T forms, have also been analyzed for a better understanding of the physiological functions in different conformations. (Abstract shortened by UMI.)
New precise measurement of muonium hyperfine structure interval at J-PARC
Energy Technology Data Exchange (ETDEWEB)
Ueno, Y., E-mail: yueno@radphys4.c.u-tokyo.ac.jp [University of Tokyo, Graduate School of Arts and Sciences (Japan); Aoki, M. [Osaka University, Graduate School of Science (Japan); Fukao, Y. [KEK (Japan); Higashi, Y.; Higuchi, T. [University of Tokyo, Graduate School of Arts and Sciences (Japan); Iinuma, H.; Ikedo, Y. [KEK (Japan); Ishida, K. [RIKEN (Japan); Ito, T. U. [Japan Atomic Energy Agency (Japan); Iwasaki, M. [RIKEN (Japan); Kadono, R. [KEK (Japan); Kamigaito, O. [RIKEN (Japan); Kanda, S. [University of Tokyo, Department of Physics (Japan); Kawall, D. [University of Massachusetts, Amherst, Department of Physics (United States); Kawamura, N.; Koda, A.; Kojima, K. M. [KEK (Japan); Kubo, M. K. [International Christian University, Graduate School of Arts and Science (Japan); Matsuda, Y. [University of Tokyo, Graduate School of Arts and Sciences (Japan); Mibe, T. [KEK (Japan); and others
2017-11-15
MuSEUM is an international collaboration aiming at a new precise measurement of the muonium hyperfine structure at J-PARC (Japan Proton Accelerator Research Complex). Utilizing its intense pulsed muon beam, we expect a ten-fold improvement for both measurements at high magnetic field and zero magnetic field. We have developed a sophisticated monitoring system, including a beam profile monitor to measure the 3D distribution of muonium atoms to suppress the systematic uncertainty.
Energy Technology Data Exchange (ETDEWEB)
Kwon, Nam Ic [Hankuk University of foreign studies, Seoul (Korea)
2000-03-01
The source of anomalous broad linewidth of 3{sup 3}P{sub 1},{sub 2},{sub 3}-3{sup 3}D{sub 2},{sub 3},4(3s') transition was explained. The broad optogalvanic spectrum was consisted of two gaussian peaks of different linewidths, and they are separated by 250 MHz. The Narrow peak, which has linewidth of room temperature, is from oxygen atoms already separated, and the shifted broad peak, which has linewidth corresponding to a temperature of 9000 K, is from weakly bound molecular ions. Obtained hyperfine spectrum of fluorine atom at the expected frequency, was too weak to analyze hyperfine structure constants. Microwave discharge might be necessary for higher density of excited state. 16 refs., 11 figs. (Author)
Shamim, K.; Siddiqui, I.; Windholz, L.
2011-10-01
We present 39 odd and 15 even parity newly discovered fine structure levels of Pr I with low angular momentum: J = 1/2, 3/2 and 5/2. Spectral lines in the range 4200 Å to 7500 Å were experimentally investigated using laser induced fluorescence spectroscopy in a hollow cathode discharge lamp. The levels were discovered by analysis of the recorded hyperfine patterns of the investigated transitions. With the help of these levels, 119 spectral lines were classified directly by laser excitation and 127 lines were classified as fluorescence lines.
Host material induced hyperfine structure of F{sup +} centres EPR spectra in CaS
Energy Technology Data Exchange (ETDEWEB)
Seeman, Viktor, E-mail: viktor.seeman@ut.ee; Dolgov, Sergei; Maaroos, Aarne
2017-05-15
The hyperfine structure (HFS) of F{sup +} centres in CaS single crystals due to the interaction with {sup 33}S and {sup 43}Ca nuclei was observed in EPR spectra for the first time. Angular variations of the HFS were measured for rotation of magnetic field in {100} and {110} crystallographic planes. Using measured orientation-dependent EPR spectra and the EPR NMR program, the parameters of the spin Hamiltonian were determined. In case of {sup 33}S nucleus there is a strong dependence of the F{sup +} centre EPR spectrum on the quadrupole term whereas for {sup 43}Ca nucleus this dependence is insignificant.
High resolution spectroscopy of the hyperfine structure splitting in 97,99Tc
Raeder, Sebastian; Kron, Tobias; Heinke, Reinhard; Henares, Jose L.; Lecesne, Nathalie; Schönberg, Pascal; Trümper, Marcel; Wendt, Klaus
2017-11-01
Resonance ionization mass spectrometry is an efficient tool for detecting trace amounts of long-lived radio-isotopes in environmental samples. For absolute quantification a tracer with identical atomic properties and chemical behavior is needed to prevent a possible dependency onto the absolute efficiency for the analytical method. For an application in 99Tc, the isotope 97Tc could serve as a potential tracer. Therefore the optical transitions of an efficient ionization scheme for technetium were investigated for the two odd mass isotopes 97,99Tc, both with a nuclear spin of I={9}/{2}. Using a pulsed, single mode laser with narrow bandwidth, the hyperfine structures (HFS) of two transitions were fully resolved. The observed isotope shift is small in comparison to the width of the hyperfine structure splitting. This is ideal for the application of 97Tc as tracer isotope for 99Tc quantification. The evaluation of the observed HFS splitting results in a first experimental value for the magnetic dipole for 97Tc of μ=+5.82(9) μ N .
Hyperfine structure in 229gTh3+ as a probe of the 229gTh→ 229mTh nuclear excitation energy.
Beloy, K
2014-02-14
We identify a potential means to extract the 229gTh→ 229mTh nuclear excitation energy from precision microwave spectroscopy of the 5F(5/2,7/2) hyperfine manifolds in the ion 229gTh3+. The hyperfine interaction mixes this ground fine structure doublet with states of the nuclear isomer, introducing small but observable shifts to the hyperfine sublevels. We demonstrate how accurate atomic structure calculations may be combined with the measurement of the hyperfine intervals to quantify the effects of this mixing. Further knowledge of the magnetic dipole decay rate of the isomer, as recently reported, allows an indirect determination of the nuclear excitation energy.
Structural, electronic, and hyperfine properties of pure and Ta-doped m-ZrO_{2}
DEFF Research Database (Denmark)
Taylor, M.A.; Alonso, R.E.; Errico, L.A.
2012-01-01
A combination of experiments and ab initio quantum-mechanical calculations has been applied to examine electronic, structural, and hyperfine interactions in pure and Ta-doped zirconium dioxide in its monoclinic phase (m-ZrO2). From the theoretical point of view, the full-potential linear augmente...
Tubergen, M. J.; Lesarri, A.; Suenram, R. D.; Samuels, A. C.; Jensen, J. O.; Ellzy, M. W.; Lochner, J. M.
2005-10-01
Rotational spectra have been recorded for both the 35Cl and 37Cl isotopic forms of two structural conformations of 2-chloroethyl ethyl sulfide (CEES). The rotational constants of the 35Cl and 37Cl isotopomers were used to identify the conformational isomers. A total of 236 hyperfine transitions have been assigned for 47 rotational transitions of the 35Cl isotope of a GGT conformer, and 146 hyperfine have been assigned for 37 rotational transitions of the 37Cl isotopomer. For the second conformer, a total of 128 (110) hyperfine and 30 (28) rotational transitions have also been assigned to the 35Cl ( 37Cl) isotopes of a TGT conformation. The extensive hyperfine splitting data, measured to high resolution with a compact Fourier transform microwave spectrometer, were used to determine both the diagonal and off-diagonal elements of the 35Cl and 37Cl nuclear quadrupole coupling tensors in the inertial tensor principal axis system. The experimental rotational constant data, as well as the 35Cl and 37Cl nuclear quadrupole coupling tensors, were compared to the results from 27 optimized ab initio (HF/6-311++G ∗∗ and MP2/6-311++G ∗∗) model structures.
Structural, magnetic and hyperfine characterizations of nanocrystalline Zn-Cd doped nickel ferrites
Aakash; Nordblad, Per; Rajendra Mohan; Mukherjee, Samrat
2017-11-01
In our present work, we have synthesized a series of Cd-Zn doped nickel ferrite ((Cd0.5-xZnx)Ni0.5Fe2O4; x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5) through standard chemical co-precipitation method to study the influence of diamagnetic ions (Cd, Zn) on the magnetic properties of ferrites. XRD and Raman spectroscopy were employed for the structural characterizations. The refinement of the X-ray diffractogram data augmented by the Williamson-Hall plots showed the presence of Cd2+ vacancies and a strained crystal structure. The vibrational spectroscopy indicated the presence of lower space-group symmetry and a distorted crystal structure. Magnetic measurements showed the samples possessed low magnetic anisotropy along with a canted spin structure. The Mössbauer measurements confirmed the cation distribution and gave evidence of super transferred hyperfine interactions arising due to canted spin structure of the system.
Puzzarini, Cristina; Cazzoli, Gabriele; Harding, Michael E; Vázquez, Juana; Gauss, Jürgen
2015-03-28
Guided by theoretical predictions, the hyperfine structures of the rotational spectra of mono- and bideuterated-water containing (17)O have been experimentally investigated. To reach sub-Doppler resolution, required to resolve the hyperfine structure due to deuterium quadrupole coupling as well as to spin-rotation (SR) and dipolar spin-spin couplings, the Lamb-dip technique has been employed. The experimental investigation and in particular, the spectral analysis have been supported by high-level quantum-chemical computations employing coupled-cluster techniques and, for the first time, a complete experimental determination of the hyperfine parameters involved was possible. The experimentally determined (17)O spin-rotation constants of D2 (17)O and HD(17)O were used to derive the paramagnetic part of the corresponding nuclear magnetic shielding constants. Together with the computed diamagnetic contributions as well as the vibrational and temperature corrections, the latter constants have been employed to confirm the oxygen nuclear magnetic shielding scale, recently established on the basis of spin-rotation data for H2 (17)O [Puzzarini et al., J. Chem. Phys. 131, 234304 (2009)].
Systematic model calculations of the hyperfine structure in light and heavy ions
Tomaselli, M; Nörtershäuser, W; Ewald, G; Sánchez, R; Fritzsche, S; Karshenboim, S G
2003-01-01
Systematic model calculations are performed for the magnetization distributions and the hyperfine structure (HFS) of light and heavy ions with a mass close to A ~ 6 208 235 to test the interplay of nuclear and atomic structure. A high-precision measurement of lithium-isotope shifts (IS) for suitable transition, combined with an accurate theoretical evaluation of the mass-shift contribution in the respective transition, can be used to determine the root-mean-square (rms) nuclear-charge radius of Li isotopes, particularly of the halo nucleus /sup 11/Li. An experiment of this type is currently underway at GSI in Darmstadt and ISOLDE at CERN. However, the field-shift contributions between the different isotopes can be evaluated using the results obtained for the charge radii, thus casting, with knowledge of the ratio of the HFS constants to the magnetic moments, new light on the IS theory. For heavy charged ions the calculated n- body magnetization distributions reproduce the HFS of hydrogen-like ions well if QED...
Unravelling the local structure of topological crystalline insulators using hyperfine interactions
Phenomena emerging from relativistic electrons in solids have become one the main topical subjects in condensed matter physics. Among a wealth of intriguing new phenomena, several classes of materials have emerged including graphene, topological insulators and Dirac semi-metals. This project is devoted to one such class of materials, in which a subtle distortion of the crystalline lattice drives a material through different topological phases: Z$_{2}$ topological insulator (Z$_{2}$-TI), topological crystalline insulator (TCI), or ferroelectric Rashba semiconductor (FERS). We propose to investigate the local structure of Pb$_{1-x}$Sn$_{x}$Te and Ge$_{1-x}$Sn$_{x}$Te (with $\\textit{x}$ from 0 to 1) using a combination of experimental techniques based on hyperfine interactions: emission Mössbauer spectroscopy (eMS) and perturbed angular correlation spectroscopy (PAC). In particular, we propose to study the effect of composition ($\\textit{x}$ in Pb$_{1-x}$Sn$_{x}$Te and Ge$_{1-x}$Sn$_{x}$Te) on: \\\\ \\\\(1) the mag...
Spectroscopy Apparatus for the Measurement of The Hyperfine Structure of Antihydrogen
Malbrunot, C.; Diermaier, M.; Dilaver, N.; Friedreich, S.; Kolbinger, B.; Lehner, S.; Lundmark, R.; Massiczek, O.; Radics, B.; Sauerzopf, C.; Simon, M.; Widmann, E.; Wolf, M.; Wünschek, B.; Zmeskal, J.
2014-02-04
The ASACUSA CUSP collaboration at the Antiproton Decelerator (AD) of CERN is planning to measure the ground-state hyperfine splitting of antihydrogen using an atomic spectroscopy beamline. We describe here the latest developments on the spectroscopy apparatus developed to be coupled to the antihydrogen production setup (CUSP).
Nuclear radiative recoil corrections to the hyperfine structure of S-states in muonic hydrogen
Faustov, R. N.; Martynenko, A. P.; Martynenko, F. A.; Sorokin, V. V.
2017-09-01
Nuclear radiative recoil corrections of order α( Zα)5 to the hyperfine splitting of S-states in muonic hydrogen are calculated on the basis of quasipotential method in quantum electrodynamics. The calculation is performed in the infrared safe Fried-Yennie gauge. Modern experimental data on the proton form factors are used.
Energy Technology Data Exchange (ETDEWEB)
Leary, A.; Wicha, A.; Harack, B.; Coish, W. A.; Hilke, M. [Department of Physics, McGill University, Ernest Rutherford Building, 3600 rue University, Montreal, Quebec H3A 2T8 (Canada); Yu, G.; Gupta, J. A. [National Research Council of Canada, M50, Montreal Road, Ottawa, Ontario K1A 0R6 (Canada); Payette, C.; Austing, D. G. [Department of Physics, McGill University, Ernest Rutherford Building, 3600 rue University, Montreal, Quebec H3A 2T8, Canada and National Research Council of Canada, M50, Montreal Road, Ottawa, Ontario K1A 0R6 (Canada)
2013-12-04
We outline the properties of the hyperfine-induced funnel structure observed in the two-electron spin blockade region of a weakly coupled vertical double quantum dot device. Hysteretic steps in the leakage current occur due to dynamic nuclear polarization when either the bias voltage or the magnetic field is swept up and down. When the bias voltage is swept, an intriguing ∼3 mT wide cusp near 0 T appears in the down-sweep position, and when the magnetic field is swept, the current at 0 T can be switched from 'low' to 'high' as the bias is increased.
Energy Technology Data Exchange (ETDEWEB)
Volotka, A.V.
2006-07-01
Studies of the hyperfine splitting in hydrogen are strongly motivated by the level of accuracy achieved in recent atomic physics experiments, which yield finally model-independent informations about nuclear structure parameters with utmost precision. Considering the current status of the determination of corrections to the hyperfine splitting of the ground state in hydrogen, this thesis provides further improved calculations by taking into account the most recent value for the proton charge radius. Comparing theoretical and experimental data of the hyperfine splitting in hydrogen the proton-size contribution is extracted and a relativistic formula for this contribution is derived in terms of moments of the nuclear charge and magnetization distributions. An iterative scheme for the determination of the Zemach and magnetic radii of the proton is proposed. As a result, the Zemach and magnetic radii are determined and the values are compared with the corresponding ones deduced from data obtained in electron-proton scattering experiments. The extraction of the Zemach radius from a rescaled difference between the hyperfine splitting in hydrogen and in muonium is considered as well. Investigations of forbidden radiative transitions in few-electron ions within ab initio QED provide a most sensitive tool for probing the influence of relativistic electron-correlation and QED corrections to the transition rates. Accordingly, a major part of this thesis is devoted to detailed studies of radiative and interelectronic-interaction effects to the transition probabilities. The renormalized expressions for the corresponding corrections in one- and twoelectron ions as well as for ions with one electron over closed shells are derived employing the two-time Green's function method. Numerical results for the correlation corrections to magnetic transition rates in He-like ions are presented. For the first time also the frequency-dependent contribution is calculated, which has to be
Energy Technology Data Exchange (ETDEWEB)
Czaplinski, W.
1992-12-31
Hyperfine effects in the symmetric collisions of the 2s metastable muonic hydrogen with hydrogen atoms: (p{mu}){sub 2s} + H, (d{mu}){sub 2s} + D, (t{mu}){sub 2s} + t are presented. Elastic and spin-flip cross sections for the scattering of The 2s muonic atoms are calculated in the two-level approximation as a function of collision energy. The corresponding formulae are derived with inclusion of electron screening and Lamb-shift between 2s and 2p energy levels of the muonic atom. The obtained spin-flip cross sections are about two orders of magnitude higher than their ground state counterparts and are much more influenced by electron screening. The rates of the spin-flip transitions are also calculated and are found to be about three orders of magnitude higher than the decay rate of the 2s state. (author). 65 refs, 15 figs, 4 tabs.
Energy Technology Data Exchange (ETDEWEB)
Mizrahi, M., E-mail: mizrahi@fisica.unlp.edu.a [Departamento de Fisica, Facultad de Ciencias Exactas UNLP, IFLP-CONICET. C.C. 67 1900 La Plata (Argentina); Cabrera, A.F.; Desimoni, J. [Departamento de Fisica, Facultad de Ciencias Exactas UNLP, IFLP-CONICET. C.C. 67 1900 La Plata (Argentina)
2010-04-16
The evolution with milling time (t{sub m}) of the structural and hyperfine properties of mechanically alloyed (Fe{sub 79}Mn{sub 21}){sub 0.85}Cu{sub 0.15} and (Fe{sub 79}Mn{sub 21}){sub 0.70}Cu{sub 0.30} nominal composition samples are reported. The samples milled during t{sub m} = 1, 3, 6, 9, 12, 15 and 18 h are characterized by X-ray diffraction (XRD) and Moessbauer spectroscopy. From the XRD results two phases are observed, a BCC one corresponding to {alpha}-Fe(Mn, Cu) and a FCC-phase associated to Fe-Mn-Cu solid solution. Moessbauer spectra show complex structure evidencing several Fe environments. Two hyperfine magnetic field distributions were used to reproduce the spectra, a high magnetic field interaction ascribed to the BCC phase and a low hyperfine magnetic field distribution linked to the FCC solid solution. An increment in the average hyperfine magnetic field (B{sub hf}) and in the isomer shift ({delta}) values of the low hyperfine magnetic field distribution is observed when the milling time increases. All the structural and hyperfine parameters remain without changes after 9 h of milling. Once this stationary regime is archived, the B{sub hf} of the (Fe{sub 79}Mn{sub 21}){sub 0.85}Cu{sub 0.15} sample resulted higher than that of the (Fe{sub 79}Mn{sub 21}){sub 0.70}Cu{sub 0.30} one.
Siddiqui, Imran; Khan, Shamim; Windholz, Laurentius
2014-05-01
We present 66 even and 58 odd parity newly discovered fine structure levels of Pr I with high angular momentum: J = 15/2, 17/2 and 19/2 and 21/2. Spectral lines in the range 4200 Å to 7500 Å were experimentally investigated using laser induced fluorescence spectroscopy in a hollow cathode discharge lamp. The levels were discovered by analysis of the recorded hyperfine patterns of the investigated transitions. More than 800 spectral lines could be classified with help of these levels. Supplementary material in the form of one pdf file available from the Journal web page at http://dx.doi.org/10.1140/epjd/e2014-50025-7
Hyperfine magnetic fields in substituted Finemet alloys
Energy Technology Data Exchange (ETDEWEB)
Brzózka, K., E-mail: k.brzozka@uthrad.pl [University of Technology and Humanities in Radom, Department of Physics (Poland); Sovák, P. [P.J. Šafárik University, Institute of Physics (Slovakia); Szumiata, T.; Gawroński, M.; Górka, B. [University of Technology and Humanities in Radom, Department of Physics (Poland)
2016-12-15
Transmission Mössbauer spectroscopy was used to determine the hyperfine fields of Finemet-type alloys in form of ribbons, substituted alternatively by Mn, Ni, Co, Al, Zn, V or Ge of various concentration. The comparative analysis of magnetic hyperfine fields was carried out which enabled to understand the role of added elements in as-quenched as well as annealed samples. Moreover, the influence of the substitution on the mean direction of the local hyperfine magnetic field was examined.
Fang, Zuyun
1988-12-01
Measurements of the hyperfine spectra of 38-yr ^{207}Bi and 3.7 times 10^5-yr ^{208}Bi in the 6p^3 ^4S_{3/2} - 6p^27s ^4P_{1/2} 306.7-nm resonance line were made using laser spectroscopic methods. The atomic excitation was produced with use of the frequency doubled output of a tunable ring dye laser. Laser absorption spectroscopy was used for the ^ {208}Bi measurement, while fluorescence spectroscopy, with photon counting detection, was used for ^{208}Bi. The experiments of ^{207}Bi were performed in both zero and high (0.7515 T) magnetic fields. The latter also provided a reliable measurement of the nuclear spin of ^{207}Bi. The results obtained from the ^ {208}Bi spectra are: A(^4P _{1/2}) = 4911(17)MHz and B( ^4S_{3/2}) = -314(92)MHz. These give the values: mu = 4.523(16) mu_{N} and Q = - 0.39(12)b. The measured isotope shift is: IS( ^{208}Bi-^{209 }Bi) = 1870(63)MHz. The results for ^{207} Bi are: I = 9/2, A(^4P_{1/2 }) = 4900.0(8.1)MHz, A(^4S_ {1/2}) = -444.6(1.5)MHz and B(^4S_{1/2}) = -443(17)MHz. These give the values: mu = 4.062(8)mu_ {N} and Q = -0.55(2)b. The measured isotope shift is: IS(^{207 }Bi-^{209}Bi) = 2997(10)MHz. The isotope shift odd-even staggering parameter for ^{208}Bi, gamma = 0.752(43), was derived and used for an isotonic comparison. The measured nuclear magnetic moments are in agreement with theoretical predictions. An improved calculation of the isotope shift constant using a diffuse nuclear charge model is given and a weak, but significant, model dependence of the isotope shifts was found.
Energy Technology Data Exchange (ETDEWEB)
Puzzarini, Cristina, E-mail: cristina.puzzarini@unibo.it; Cazzoli, Gabriele [Dipartimento di Chimica “Giacomo Ciamician,” Università degli Studi di Bologna, Via Selmi 2, I-40126 Bologna (Italy); Harding, Michael E. [Institut für Nanotechnologie, Karlsruher Institut für Technologie (KIT), Campus Nord, Postfach 3640, D-76021 Karlsruhe (Germany); Center for Theoretical Chemistry, Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas 78712 (United States); Vázquez, Juana [Center for Theoretical Chemistry, Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas 78712 (United States); Gauss, Jürgen, E-mail: gauss@uni-mainz.de [Institut für Physikalische Chemie, Universität Mainz, D-55099 Mainz (Germany)
2015-03-28
Guided by theoretical predictions, the hyperfine structures of the rotational spectra of mono- and bideuterated-water containing {sup 17}O have been experimentally investigated. To reach sub-Doppler resolution, required to resolve the hyperfine structure due to deuterium quadrupole coupling as well as to spin-rotation (SR) and dipolar spin-spin couplings, the Lamb-dip technique has been employed. The experimental investigation and in particular, the spectral analysis have been supported by high-level quantum-chemical computations employing coupled-cluster techniques and, for the first time, a complete experimental determination of the hyperfine parameters involved was possible. The experimentally determined {sup 17}O spin-rotation constants of D{sub 2}{sup 17}O and HD{sup 17}O were used to derive the paramagnetic part of the corresponding nuclear magnetic shielding constants. Together with the computed diamagnetic contributions as well as the vibrational and temperature corrections, the latter constants have been employed to confirm the oxygen nuclear magnetic shielding scale, recently established on the basis of spin-rotation data for H{sub 2}{sup 17}O [Puzzarini et al., J. Chem. Phys. 131, 234304 (2009)].
Xu, Liang; Yin, Yanning; Wei, Bin; Xia, Yong; Yin, Jianping
2016-01-01
More recently, laser cooling of the diatomic radical magnesium monofluoride (24Mg19F ) is being experimentally preformed [Appl. Phys. Express 8, 092701 (2015), 10.7567/APEX.8.092701 and Opt. Express 22, 28645 (2014), 10.1364/OE.22.028645] and was also studied theoretically [Phys. Rev. A 91, 042511 (2015), 10.1103/PhysRevA.91.042511]. However, some important problems still remain unsolved, so, in our paper, we perform further theoretical study for the feasibility of laser cooling and trapping the 24Mg19F molecule. At first, the highly diagonal Franck-Condon factors of the main transitions are verified by the closed-form approximation, Morse approximation, and Rydberg-Klein-Rees inversion methods, respectively. Afterwards, we investigate the lower X 2Σ1/2 + hyperfine manifolds using a quantum effective Hamiltonian approach and obtain the zero-field hyperfine spectrum with an accuracy of less than 30 kHz ˜5 μ K compared with the experimental results, and then find out that one cooling beam and one or two repumping beams with their first-order sidebands are enough to implement an efficient laser slowing and cooling of 24Mg19F . Meanwhile, we also calculate the accurate hyperfine structure magnetic g factors of the rotational state (X 2Σ1/2 +,N =1 ) and briefly discuss the influence of the external fields on the hyperfine structure of 24Mg19F as well as its possibility of preparing three-dimensional magneto-optical trapping. Finally we give an explanation for the difference between the Stark and Zeeman effects from the perspective of parity and time reversal symmetry. Our study shows that, besides appropriate excitation wavelengths, the short lifetime for the first excited state A 2Π1 /2 , and lighter mass, the 24Mg19F radical could be a good candidate molecule amenable to laser cooling and magneto-optical trapping.
Energy Technology Data Exchange (ETDEWEB)
Wood, M. P.; Lawler, J. E.; Den Hartog, E. A. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Sneden, C. [Department of Astronomy and McDonald Observatory, University of Texas, Austin, TX 78712 (United States); Cowan, J. J., E-mail: mpwood@wisc.edu, E-mail: jelawler@wisc.edu, E-mail: eadenhar@wisc.edu, E-mail: chris@verdi.as.utexas.edu, E-mail: cowan@nhn.ou.edu [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 (United States)
2014-10-01
New experimental absolute atomic transition probabilities are reported for 203 lines of V II. Branching fractions are measured from spectra recorded using a Fourier transform spectrometer and an echelle spectrometer. The branching fractions are normalized with radiative lifetime measurements to determine the new transition probabilities. Generally good agreement is found between this work and previously reported V II transition probabilities. Two spectrometers, independent radiometric calibration methods, and independent data analysis routines enable a reduction in systematic uncertainties, in particular those due to optical depth errors. In addition, new hyperfine structure constants are measured for selected levels by least squares fitting line profiles in the FTS spectra. The new V II data are applied to high resolution visible and UV spectra of the Sun and metal-poor star HD 84937 to determine new, more accurate V abundances. Lines covering a range of wavelength and excitation potential are used to search for non-LTE effects. Very good agreement is found between our new solar photospheric V abundance, log ε(V) = 3.95 from 15 V II lines, and the solar-system meteoritic value. In HD 84937, we derive [V/H] = –2.08 from 68 lines, leading to a value of [V/Fe] = 0.24.
Energy Technology Data Exchange (ETDEWEB)
Bhattacharjee, Kaustav; Das, G. C. [Department of Metallurgical and Material Engineering, Jadavpur University, Kolkata 700032 (India); Pati, Satya P.; Das, D. [UGC-DAE Consortium for Scientific Research, Kolkata Centre, III/LB-8, Bidhannagar, Kolkata 700 098 (India); Chattopadhyay, K. K., E-mail: kalyan-chattopadhyay@yahoo.com [Thin Film and Nanoscience Laboratory, Department of Physics, Jadavpur University, Kolkata 700032 (India)
2014-12-21
Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} nano powders were synthesized by an auto combustion method and then heat treated at different temperatures in air for a fixed time. As a consequence, a distribution in particle size and strain was incorporated within the specimens, as estimated from the Rietveld refinement analysis of the powder x-ray diffraction data. The changes in the microstructure and crystal structure parameters were carefully extracted through the refinement analysis. Thermal annealing causes increment in the dispersion and mean of the size distribution. Reallocation of cations in the lattice sites occur as a consequence of the heat treatment which was manifested in their altered unit cell length (a), r.m.s. strain (〈ε{sup 2}〉{sup 1/2}), oxygen positional parameter (u), metal-oxygen bond lengths (R{sub OA} and R{sub OB}), and the band positions (ν{sub 1}and ν{sub 2}) in the vibrational spectroscopy. We also investigate the hyperfine and magnetic properties of the samples using different instrumental techniques (with different operating time scales) like Mössbauer spectroscopy, electron paramagnetic resonance spectroscopy, and superconducting quantum interference device magnetometry. Results show that the effect of particle size distribution was manifested in their hyperfine field distribution profile, paramagnetic resonance spectra, and magnetic anisotropy energy distribution profile. Co-existence of superparamagnetic and ferrimagnetic phase was recorded at room temperature in the samples when annealed at lower temperature. However, with increase in annealing temperature, the nature of the size distribution changes and ferrimagnetic ordering predominates for the larger size nanoparticles. Thus, the effect of particle size distribution on the structural, hyperfine, and magnetic properties of various Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4} nanoparticles was investigated herein which hitherto has not been discussed in the literature.
Hyperfine interaction of Er3+ ions in Y2SiO5 : An electron paramagnetic resonance spectroscopy study
Guillot-Noël, O.; Goldner, Ph.; Du, Y. Le; Baldit, E.; Monnier, P.; Bencheikh, K.
2006-12-01
Electron paramagnetic resonance (EPR) spectroscopy of rare earth ions in crystals is a powerful tool to analyze the hyperfine structure of the rare earth ground state. This can be useful for coherent spectroscopy and quantum information applications where the hyperfine structure of the electronic levels is used. In this work, we give a detailed analysis of the hyperfine structure of the ground state [I15/24(0)] of Er3+ ions in Y2SiO5 . The electronic Zeeman, hyperfine, and quadrupole matrices are obtained from angular variations of the magnetic field in three orthogonal crystal planes. An excellent agreement is obtained between experimental and simulated magnetic field positions and relative intensities of EPR lines.
Energy Technology Data Exchange (ETDEWEB)
Sowmya, K.; Nagendra, K. N.; Sampoorna, M. [Indian Institute of Astrophysics, Koramangala, Bengaluru (India); Stenflo, J. O., E-mail: ksowmya@iiap.res.in, E-mail: knn@iiap.res.in, E-mail: sampoorna@iiap.res.in, E-mail: stenflo@astro.phys.ethz.ch [Institute of Astronomy, ETH Zurich, CH-8093 Zurich (Switzerland)
2015-12-01
Interference between magnetic substates of the hyperfine structure states belonging to different fine structure states of the same term influences the polarization for some of the diagnostically important lines of the Sun's spectrum, like the sodium and lithium doublets. The polarization signatures of this combined interference contain information on the properties of the solar magnetic fields. Motivated by this, in the present paper, we study the problem of polarized scattering on a two-term atom with hyperfine structure by accounting for the partial redistribution in the photon frequencies arising due to the Doppler motions of the atoms. We consider the scattering atoms to be under the influence of a magnetic field of arbitrary strength and develop a formalism based on the Kramers–Heisenberg approach to calculate the scattering cross section for this process. We explore the rich polarization effects that arise from various level-crossings in the Paschen–Back regime in a single scattering case using the lithium atomic system as a concrete example that is relevant to the Sun.
Energy Technology Data Exchange (ETDEWEB)
Akkouche, K. [LMMC, M' hamed Bougara University, Boumerdes 35000 (Algeria); Guittoum, A., E-mail: guittoum@yahoo.fr [Nuclear Research Centre of Algiers, 2 Bd Frantz Fanon, BP399 Alger-Gare, Algiers (Algeria); Boukherroub, N. [LMMC, M' hamed Bougara University, Boumerdes 35000 (Algeria); Souami, N. [Nuclear Research Centre of Algiers, 2 Bd Frantz Fanon, BP399 Alger-Gare, Algiers (Algeria)
2011-11-15
Nanostructured Fe{sub 50}Co{sub 50} powders were prepared by mechanical alloying of Fe and Co elements in a vario-planetary high-energy ball mill. The structural properties, morphology changes and local iron environment variations were investigated as a function of milling time (in the 0-200 h range) by means of X-ray diffraction, scanning electron microscopy (SEM), energy dispersive X-ray analysis and {sup 57}Fe Moessbauer spectroscopy. The complete formation of bcc Fe{sub 50}Co{sub 50} solid solution is observed after 100 h milling. As the milling time increases from 0 to 200 h, the lattice parameter decreases from 0.28655 nm for pure Fe to 0.28523 nm, the grain size decreases from 150 to 14 nm, while the meal level of strain increases from 0.0069% to 1.36%. The powder particle morphology at different stages of formation was observed by SEM. The parameters derived from the Moessbauer spectra confirm the beginning of the formation of Fe{sub 50}Co{sub 50} phase at 43 h of milling. After 200 h of milling the average hyperfine magnetic field of 35 T suggests that a disordered bcc Fe-Co solid solution is formed. - Highlights: > Nanostructured Fe{sub 50}Co{sub 50} powders were successfully prepared by mechanical alloying process. > Final average grain size value achieved after 200 h of milling was 14 nm. > For the longest milling time the majority of particle grains observed by SEM exhibits a round shape with small diameter.
Energy Technology Data Exchange (ETDEWEB)
Harack, B.; Leary, A.; Coish, W. A.; Hilke, M. [Department of Physics, McGill University, Ernest Rutherford Building, 3600 rue University, Montreal, Quebec H3A 2T8 (Canada); Yu, G.; Gupta, J. A. [National Research Council of Canada, M50, Montreal Road, Ottawa, Ontario K1A 0R6 (Canada); Payette, C.; Austing, D. G. [Department of Physics, McGill University, Ernest Rutherford Building, 3600 rue University, Montreal, Quebec H3A 2T8, Canada and National Research Council of Canada, M50, Montreal Road, Ottawa, Ontario K1A 0R6 (Canada)
2013-12-04
We outline power spectra and auto correlation analysis performed on temporal oscillations in the tunneling current of coupled vertical quantum dots. The current is monitored for ∼2325 s blocks as the magnetic field is stepped through a high bias feature displaying hysteresis and switching: hallmarks of the hyperfine interaction. Quasi-periodic oscillations of ∼2 pA amplitude and of ∼100 s period are observed in the current inside the hysteretic feature. Compared to the baseline current outside the hysteretic feature the power spectral density is enhanced by up to three orders of magnitude and the auto correlation displays clear long lived oscillations about zero.
Energy Technology Data Exchange (ETDEWEB)
Cazzoli, Gabriele; Lattanzi, Valerio; Puzzarini, Cristina [Dipartimento di Chimica “Giacomo Ciamician”, Università di Bologna, Via Selmi 2, I-40126 Bologna (Italy); Alonso, José Luis [Grupo de Espectroscopía Molecular (GEM), Unidad Asociada CSIC, Edificio Quifima, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Universidad de Valladolid, E-47005 Valladolid (Spain); Gauss, Jürgen, E-mail: cristina.puzzarini@unibo.it [Institut für Physikalische Chemie, Universität Mainz, D-55099 Mainz (Germany)
2015-06-10
The rotational spectrum of the mono-deuterated isotopologue of water, HD{sup 16}O, has been investigated in the millimeter- and submillimeter-wave frequency regions, up to 1.6 THz. The Lamb-dip technique has been exploited to obtain sub-Doppler resolution and to resolve the hyperfine (hf) structure due to the deuterium and hydrogen nuclei, thus enabling the accurate determination of the corresponding hf parameters. Their experimental determination has been supported by high-level quantum-chemical calculations. The Lamb-dip measurements have been supplemented by Doppler-limited measurements (weak high-J and high-frequency transitions) in order to extend the predictive capability of the available spectroscopic constants. The possibility of resolving hf splittings in astronomical spectra has been discussed.
Sargsyan, Armen; Hakhumyan, Grant; Tonoyan, Ara; Papoyan, Aram; Leroy, Claude; Sarkisyan, David
2016-01-01
Decoupling of total electronic and nuclear spin moments of Cs atoms in external magnetic field for the case of atomic $D_1$ line, leading to onset of the hyperfine Paschen-Back regime has been studied theoretically and experimentally. Selective reflection of laser radiation from an interface of dielectric window and atomic vapor confined in a nanocell with 300 nm gap thickness was implemented for the experimental studies. The real time derivative of selective reflection signal with a frequency position coinciding with atomic transitions was used in measurements, providing $\\sim$ 40 MHz spectral resolution and linearity of signal response in respect to transition probability. Behavior of 28 individual Zeeman transitions in a wide range of longitudinal magnetic field (0 - 6 kG) has been tracked under excitation of Cs vapor by a low-intensity $\\sigma^+$- polarized cw laser radiation. For $B\\ge 6~$kG, only 8 transitions with nearly equal probabilities and the same frequency slope remained in the spectrum, which i...
Oliveira, João P. C.; Rivelino, Roberto
2010-05-01
Density-functional-theory (DFT) calculations of the hyperfine coupling constants (HFCCs) are systematically reported for the lithium superoxide (LiO2) structural isomers in the doublet ground states, \\tilde X 2A2 and 2Π. Also, structure, harmonic frequencies, rotational constants and dipole moments have been computed at different levels of theory. Our results calculated for the 2A2 state are compared with the available data of matrix-isolated LiO2. Geometric parameters and vibrational modes compare well with available experimental data. However, the present density-functional results show a strong dependence of the isotropic HFCCs on the level of approximation as well as the molecular geometry. Our results confirm that the anisotropic contributions are less sensitive to the exchange-correlation potentials and basis sets. We have obtained the best estimate of the isotropic HFCC (in comparison with the experimental trends) by using the hybrid scheme that combines the Perdew-Wang's 1991 correlation functional with the adiabatic connection. This study allows us to gauge DFT methods for future applications in the alkali superoxide series, as well as open-shell metal centres interacting with dioxygen in biological systems.
Energy Technology Data Exchange (ETDEWEB)
Oliveira, Joao P C; Rivelino, Roberto, E-mail: rivelino@ufba.b [Instituto de FIsica, Universidade Federal da Bahia, 40210-340 Salvador, Bahia (Brazil)
2010-05-14
Density-functional-theory (DFT) calculations of the hyperfine coupling constants (HFCCs) are systematically reported for the lithium superoxide (LiO{sub 2}) structural isomers in the doublet ground states, (tilde X){sup 2}A{sub 2} and {sup 2{Pi}}. Also, structure, harmonic frequencies, rotational constants and dipole moments have been computed at different levels of theory. Our results calculated for the {sup 2}A{sub 2} state are compared with the available data of matrix-isolated LiO{sub 2}. Geometric parameters and vibrational modes compare well with available experimental data. However, the present density-functional results show a strong dependence of the isotropic HFCCs on the level of approximation as well as the molecular geometry. Our results confirm that the anisotropic contributions are less sensitive to the exchange-correlation potentials and basis sets. We have obtained the best estimate of the isotropic HFCC (in comparison with the experimental trends) by using the hybrid scheme that combines the Perdew-Wang's 1991 correlation functional with the adiabatic connection. This study allows us to gauge DFT methods for future applications in the alkali superoxide series, as well as open-shell metal centres interacting with dioxygen in biological systems.
Energy Technology Data Exchange (ETDEWEB)
Lim, Jung Tae; Kim, Chul Sung, E-mail: cskim@kookmin.ac.kr [Department of Physics, Kookmin University, Seoul 136-702 (Korea, Republic of)
2015-05-07
The polycrystalline samples of Ba{sub 3}Co{sub 2−x}Zn{sub x}Fe{sub 24}O{sub 41} (x = 0.0, 0.5, 1.0, 1.5, and 2.0) were synthesized by the standard solid-state-reaction method. Based on the XRD patterns analyzed by Rietveld refinement, the structure was determined to be single-phased hexagonal with space group of P6{sub 3}/mmc. With increasing Zn ion concentration, the unit cell volume (V{sub u}) of samples was increased, as the sites of Fe{sup 3+} ions changed from tetrahedral to octahedral sites. We have obtained zero-field Mössbauer spectra of all samples at various temperatures ranging from 4.2 to 750 K. The measured spectra below T{sub C} were analyzed with six distinguishable sextets due to the superposition of ten-sextets for Fe sites, corresponding to the Z-type hexagonal ferrite. Also, the hyperfine field (H{sub hf}) and electric quadrupole shift (E{sub Q}) have shown abrupt changes around spin transition temperature (T{sub S}). In addition, Mössbauer spectra of all samples at 4.2 K were taken with an applied field ranging from 0 to 50 kOe, which indicates the decrease in the canting angle between applied field and H{sub hf} of samples with increasing Zn concentration.
7P1/2 hyperfine splitting in 206 , 207 , 209 , 213Fr and the hyperfine anomaly
Zhang, J.; Orozco, L. A.; Collister, R.; Gwinner, G.; Tandecki, M.; Behr, J. A.; Pearson, M. R.; Gomez, E.; Aubin, S.
2013-05-01
We perform precision measurements on francium, the heaviest alkali with no stable isotopes, at the recently commissioned Francium Trapping Facility at TRIUMF. A combination of RF and optical spectroscopy allows better than 10 ppm (statistical) measurements of the 7P1 / 2 state hyperfine splitting for the isotopes 206 , 207 , 209 , 213Fr, in preparation for weak interaction studies. Together with previous measurements of the ground state hyperfine structure, it is possible to extract the hyperfine anomaly. This is a correction to the point interaction of the nuclear magnetic moment and the electron wavefunction, known as the Bohr Weisskopf effect. Our measurements extend previous measurements to the neutron closed shell isotope (213) as well as further in the neutron deficient isotopes (206, 207). Work supported by NSERC and NRC from Canada, NSF and DOE from USA, CONYACT from Mexico.
Energy Technology Data Exchange (ETDEWEB)
Rowe, Mary Anderson [Univ. of California, Berkeley, CA (United States)
1999-05-01
This thesis describes an experiment in which a neutral atom laser trap loaded with radioactive ^{21}Na was improved and then used for measurements. The sodium isotope (half-life=22 sec) is produced on line at the 88 in. cyclotron at Lawrence Berkeley National Laboratory. The author developed an effective magnesium oxide target system which is crucial to deliver a substantive beam of ^{21}Na to the experiment. Efficient manipulation of the ^{21}Na beam with lasers allowed 30,000 atoms to be contained in a magneto-optical trap. Using the cold trapped atoms, the author measured to high precision the hyperfine splitting of the atomic ground state of ^{21}Na. She measured the 3S_{1/2}(F=1,m=0)-3S_{1/2}(F=2,m=0) atomic level splitting of ^{21}Na to be 1,906,471,870±200 Hz. Additionally, she achieved initial detection of beta decay from the trap and evaluated the prospects of precision beta decay correlation studies with trapped atoms.
Modi, K. B.; Raval, P. Y.; Dulera, S. V.; Kathad, C. R.; Shah, S. J.; Trivedi, U. N.; Chandra, Usha
2015-06-01
Two specimens of copper ferrite, CuFe2O4, have been synthesized by double sintering ceramic technique with different thermal history i.e. slow cooled and quenched. X-ray diffractometry has confirmed single phase fcc spinel structure for slow cooled sample while tetragonal distortion is present in quenched sample. Mossbauer spectral analysis for slow-cooled copper ferrite reveals super position of two Zeeman split sextets along with paramagnetic singlet in the centre position corresponds to delafossite (CuFeO2) phase that is completely absent in quenched sample. The hyperfine interaction parameters are highly influenced by heat treatment employed.
Schraut, Johannes; Arbuznikov, Alexei V; Schinzel, Sandra; Kaupp, Martin
2011-12-09
Based on broken-symmetry density functional calculations, the (55)Mn hyperfine tensors of a series of exchange-coupled, mixed-valence, dinuclear Mn(III) Mn(IV) complexes have been computed. We go beyond previous quantum chemical work by fully including the effects of local zero-field splitting (ZFS) interactions in the spin projection, following the first-order perturbation formalism of Sage et al. [J. Am. Chem. Soc. 1989, 111, 7239]. This allows the ZFS-induced transfer of hyperfine anisotropy from the Mn(III) site to the Mn(IV) site to be described with full consideration of the orientations of local hyperfine and ZFS tensors. After scaling to correct for systematic deficiencies in the quantum chemically computed local ZFS tensors, good agreement with experimental (55)Mn anisotropies at the Mn(IV) site is obtained. The hyperfine coupling anisotropies on the Mn(III) site depend sensitively on structural distortions for a d(4) ion. The latter are neither fully reproduced by using a DFT-optimized coordination environment nor by using experimental structures. For very small exchange-coupling constants, the perturbation treatment breaks down and a dramatic sensitivity to the scaling of the local ZFS tensors is observed. These results are discussed with respect to ongoing work to elucidate the structure of the oxygen-evolving complex of photosystem II by analysis of the EPR spectra. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
The hyperfine properties of iron-gallium alloys
Energy Technology Data Exchange (ETDEWEB)
Elzain, M., E-mail: elzain@squ.edu.om; Gismelseed, A.; Al-Rawas, A.; Yousif, A.; Widatallah, H.; Al-Azri, Maya [Sultan Qaboos University, Department of Physics (Oman); Al-Barwani, M. [NYU Abu Dhabi (United Arab Emirates)
2016-12-15
The hyperfine properties at Fe site in iron-gallium alloy are calculated using the full-potential linear-augmented-plane-waves method. We have calculated the Fermi contact field (B{sub hf}) and isomer shift (δ) at the Fe site versus the number of neighbouring Ga atoms. We found that B{sub hf} decrease whereas δ increases with increasing number of neighbouring G atom. In addition we have calculated the hyperfine properties of FeGa system with DO{sub 3} structure, where various distributions of 4 the Ga atoms in the conventional unit cell are considered (including the regular DO{sub 3} structure). We found that the DO{sub 3} structure has the lowest energy as compared to the other configurations. The two distinct A and D sites of the ordered DO{sub 3} conventional unit cell have two distinct values for B{sub hf} and δ. On changing the atomic arrangement of the Ga atoms within the conventional unit cell, the configuration of the A site is maintained whereas that of the D site becomes imperfect. The contact magnetic hyperfine fields of the D-like sites in the imperfect structures are lower than that of the DO{sub 3}D site.
Numerical Simulations of Hyperfine Transitions of Antihydrogen
Kolbinger, B.; Diermaier, M.; Lehner, S.; Malbrunot, C.; Massiczek, O.; Sauerzopf, C.; Simon, M.C.; Widmann, E.
2015-02-04
One of the ASACUSA (Atomic Spectroscopy And Collisions Using Slow Antiprotons) collaboration's goals is the measurement of the ground state hyperfine transition frequency in antihydrogen, the antimatter counterpart of one of the best known systems in physics. This high precision experiment yields a sensitive test of the fundamental symmetry of CPT. Numerical simulations of hyperfine transitions of antihydrogen atoms have been performed providing information on the required antihydrogen events and the achievable precision.
Hyperfine splitting in simple ions for the search of the variation of fundamental constants
Oreshkina, Natalia S.; Cavaletto, Stefano M.; Michel, Niklas; Harman, Zoltán; Keitel, Christoph H.
2017-09-01
Numerous few-electron atomic systems are considered which can be used effectively for observing a potential variation of the fine-structure constant α and the electron-proton mass ratio me/mp . We examine optical magnetic dipole transitions between hyperfine-structure components in heavy highly charged H-like and Li-like ions with observably high sensitivity to a variation of α and me/mp . The experimental spectra of the proposed systems consist of a strong single line, which simplifies significantly the data analysis and shortens the necessary measurement time. Furthermore, we propose systems for an experimental test of the variation of quark masses and discuss the expected level of accuracy in assessing its limitations. Finally, we establish which constraints on the variation of these fundamental constants could be provided by measurements with a hyperfine-structure highly-charged-ion clock and some reference clock, showing that a significant improvement of the current limitations can be reached.
Chen, X; Rinkevicius, Z; Ruud, K; Ågren, H
2013-02-07
By analyzing a set of organic π radicals, we demonstrate that zero-point vibrational corrections give significant contributions to carbon hyperfine coupling constants, in one case even inducing a sign reversal for the coupling constant. We discuss the implications of these findings for the computational analysis of electron paramagnetic spectra based on hyperfine coupling constants evaluated at the equilibrium geometry of radicals. In particular, we note that a dynamical description that involves the nuclear motion is in many cases necessary in order to achieve a semi-quantitatively predictive theory for carbon hyperfine coupling constants. In addition, we discuss the implications of the strong dependence of the carbon hyperfine coupling constants on the zero-point vibrational corrections for the selection of exchange-correlation functionals in density functional theory studies of these constants.
Mossbauer analysis of the atomic and magnetic structure of alloys
Ovchinnikov, VV
2007-01-01
The monograph indicates the key problems that have to be solved for the further development of the Mössbauer methods for analysis of the nuclear and magnetic structure of alloys, and offer solution variants for some of these problems based on the generalised results of a wide range of theoretical and experimental investigations,including original work by the author of the book and his colleagues. Contents 1. Description of the nature of the Mössbauer effect 2. Interpretation of the ossbauer spectra of alloys 3.Electrical and magnetics hyperfine interactions of resonant nuclei in metals and
Hyperfine characterization of {beta}-zirconium tetrafluoride
Energy Technology Data Exchange (ETDEWEB)
Rivas, P.C.; Martinez, J.A.; Rodriguez, A.M.; Lopez Garcia, A.R. [Universidad Nacional de La Plata, Departamento de Fisica, Facultad de Ciencias Exactas (Argentina); Dejneka, M. [Rutgers University, Center for Ceramic Research (United States)
1997-10-15
The evolution of the hyperfine quadrupole interaction in {beta}-ZrF{sub 4} at Zr sites, is measured between 273 and 740 K via the Perturbed Angular Correlations technique. Two different quadrupole interactions, in a ratio 1:2 of relative fractions, are determined. It is observed that the compound remains stable all over the thermal range. Moisture exposure at room temperature seems not to affect the hyperfine interaction suggesting that {beta}-ZrF{sub 4} is less sensitive to air water than other varieties of zirconium fluoride.
Liu, G.; Zakharov, V.; Collins, T.; Gould, P.; Malinovskaya, S. A.
2014-04-01
We implement a four-level semiclassical model of a single pulse interacting with the hyperfine structure in ultracold rubidium aimed at control of population dynamics and quantum state preparation. We discuss a method based on pulse chirping to achieve population inversion between hyperfine states of the 5S shell. The results may prove useful for quantum operations with ultracold atoms.
Hyperfine electric parameters calculation in Si samples implanted with {sup 57}Mn→{sup 57}Fe
Energy Technology Data Exchange (ETDEWEB)
Abreu, Y., E-mail: yabreu@ceaden.edu.cu [Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN), Calle 30 No. 502 e/5ta y 7ma Ave., 11300 Miramar, Playa, La Habana (Cuba); Cruz, C.M.; Piñera, I.; Leyva, A.; Cabal, A.E. [Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN), Calle 30 No. 502 e/5ta y 7ma Ave., 11300 Miramar, Playa, La Habana (Cuba); Van Espen, P. [Departement Chemie, Universiteit Antwerpen, Middelheimcampus, G.V.130, Groenenborgerlaan 171, 2020 Antwerpen (Belgium); Van Remortel, N. [Departement Fysica, Universiteit Antwerpen, Middelheimcampus, G.U.236, Groenenborgerlaan 171, 2020 Antwerpen (Belgium)
2014-07-15
Nowadays the electronic structure calculations allow the study of complex systems determining the hyperfine parameters measured at a probe atom, including the presence of crystalline defects. The hyperfine electric parameters have been measured by Mössbauer spectroscopy in silicon materials implanted with {sup 57}Mn→{sup 57}Fe ions, observing four main contributions to the spectra. Nevertheless, some ambiguities still remain in the {sup 57}Fe Mössbauer spectra interpretation in this case, regarding the damage configurations and its evolution with annealing. In the present work several implantation environments are evaluated and the {sup 57}Fe hyperfine parameters are calculated. The observed correlation among the studied local environments and the experimental observations is presented, and a tentative microscopic description of the behavior and thermal evolution of the characteristic defects local environments of the probe atoms concerning the location of vacancies and interstitial Si in the neighborhood of {sup 57}Fe ions in substitutional and interstitial sites is proposed.
Direct observation of the hyperfine transition of ground-state positronium.
Yamazaki, T; Miyazaki, A; Suehara, T; Namba, T; Asai, S; Kobayashi, T; Saito, H; Ogawa, I; Idehara, T; Sabchevski, S
2012-06-22
We report the first direct measurement of the hyperfine transition of the ground state positronium. The hyperfine structure between ortho-positronium and para-positronium is about 203 GHz. We develop a new optical system to accumulate about 10 kW power using a gyrotron, a mode converter, and a Fabry-Pérot cavity. The hyperfine transition has been observed with a significance of 5.4 standard deviations. The transition probability is measured to be A = 3.1(-1.2)(+1.6) × 10(-8) s(-1) for the first time, which is in good agreement with the theoretical value of 3.37 × 10(-8) s(-1).
Muons as hyperfine interaction probes in chemistry
Energy Technology Data Exchange (ETDEWEB)
Ghandi, Khashayar, E-mail: kghandi@triumf.ca; MacLean, Amy [Mount Allison University, Department of Chemistry & Biochemistry (Canada)
2015-04-15
Spin polarized positive muons injected in matter serve as magnetic probes for the investigation of physical and chemical properties of free radicals, mechanisms of free radical reactions and their formations, and radiation effects. All muon techniques rely on the evolution of spin polarization (of the muon) and in that respect are similar to conventional magnetic resonance techniques. The applications of the muon as a hyperfine probe in several fields in chemistry are described.
DEFF Research Database (Denmark)
Hedegård, Erik Donovan; Kongsted, Jacob; Sauer, Stephan P. A.
2012-01-01
Calculation of hyperfine coupling constants (HFCs) of Electron Paramagnetic Resonance from first principles can be a beneficial compliment to experimental data in cases where the molecular structure is unknown. We have recently investigated basis set convergence of HFCs in d-block complexes...
Measurement and modeling of hyperfine parameters in ferroic materials
Gonçalves, João Nuno; Correia, J G
This thesis presents the results of perturbed angular correlation (PAC) experiments , an experimental technique which measures the hyperfine interaction at probes (radioactive ions implanted in the materials to study), from which one infers local information on an atomic scale. Furthermore, abinitio calculations using density functional theory electronic obtain results that directly complement the experiments, and are also used for theoretical research. These methods were applied in two families of materials. The manganites, with the possible existence of magnetic, charge, orbital and ferroelectric orders, are of fundamental and technological interest. The experimental results are obtained in the alkaline-earth manganites (Ca, Ba, Sr), with special interest due to the structural variety of possible polymorphs. With probes of Cd and In the stability of the probe and its location in a wide temperature range is established and a comparison with calculations allows the physical interpretation of the results. Cal...
Directionally independent energy gap formation due to the hyperfine interaction
Miyashita, Seiji; Raedt, Hans De; Michielsen, Kristel
2003-01-01
We study energy gap formation at the level-crossing point due to the hyperfine interaction. In contrast to the energy gap induced by the Dzyaloshinskii-Moriya interaction, the gap induced by the hyperfine interaction is independent of the direction of the magnetic field. We also study the dynamics
Structural analysis for diagnosis
DEFF Research Database (Denmark)
Izadi-Zamanabadi, Roozbeh; Blanke, M.
2002-01-01
Aiming at design of algorithms for fault diagnosis, structural analysis of systems offers concise yet easy overall analysis. Graph-based matching, which is the essential tech-nique to obtain redundant information for diagnosis, is reconsidered in this paper. Matching is reformulated as a problem...
Structural analysis for Diagnosis
DEFF Research Database (Denmark)
Izadi-Zamanabadi, Roozbeh; Blanke, M.
2001-01-01
Aiming at design of algorithms for fault diagnosis, structural analysis of systems offers concise yet easy overall analysis. Graph-based matching, which is the essential technique to obtain redundant information for diagnosis, is re-considered in this paper. Matching is re-formulated as a problem...
Electrical detection of hyperfine interactions in silicon
Energy Technology Data Exchange (ETDEWEB)
Hoehne, Felix
2012-12-15
The main focus of this work was the measurement of hyperfine interactions of defects in silicon using EDMR. We combined the high sensitivity of EDMR when compared to conventional ESR with the two most commonly used methods for the measurement of hyperfine interactions: ESEEM and ENDOR. We first demonstrated the electrical detection of ESEEM by measuring the hyperfine interactions of {sup 31}P donors in Si:P with {sup 29}Si nuclear spins. We then apply EDESEEM to P{sub b0} defects at the Si/SiO{sub 2} interface. In isotopically engineered, we observe an ESEEM modulation with a characteristic beating caused by {sup 29}Si nuclei at 4th and 5th nearest neighbor lattice sites. Then we combine pulsed ENDOR with the high sensitivity of EDMR (EDENDOR). First we demonstrate the measurement of {sup 31}P nuclear spin hyperfine transitions and the coherent manipulation and readout of the {sup 31}P nuclear spins under continuous illumination with above bandgap light. We further show that the EDENDOR method can be greatly improved by switching off the illumination during the microwave and rf pulses. This improves the signal-to-noise ratio by two orders of magnitude and removes the non-resonant background induced by the strong rf pulse allowing to measure ENDOR with a sensitivity <3000 nuclear spins. We apply EDENDOR to the {sup 31}P-P{sub b0} spin system and the {sup 31}P-SL1 spin system allowing us to compare the hyperfine interactions of bulk and interface-near donors. The pulsed illumination also makes spectroscopy of the {sup 31}P{sup +} nuclear spin possible, which due to its long coherence time of 18 ms compared to 280 {mu}s for the {sup 31}P{sub 0} nuclear spin, might be a candidate for a nuclear spin memory. In the last part, we devise a scheme for the hyperpolarization of {sup 31}P nuclei by combining pulsed optical excitation and pulsed ENDOR and demonstrate a {sup 31}P nuclear spin polarization of more than 50%. Crucial for these experiments was the development of a
Probabilistic Structural Analysis Program
Pai, Shantaram S.; Chamis, Christos C.; Murthy, Pappu L. N.; Stefko, George L.; Riha, David S.; Thacker, Ben H.; Nagpal, Vinod K.; Mital, Subodh K.
2010-01-01
NASA/NESSUS 6.2c is a general-purpose, probabilistic analysis program that computes probability of failure and probabilistic sensitivity measures of engineered systems. Because NASA/NESSUS uses highly computationally efficient and accurate analysis techniques, probabilistic solutions can be obtained even for extremely large and complex models. Once the probabilistic response is quantified, the results can be used to support risk-informed decisions regarding reliability for safety-critical and one-of-a-kind systems, as well as for maintaining a level of quality while reducing manufacturing costs for larger-quantity products. NASA/NESSUS has been successfully applied to a diverse range of problems in aerospace, gas turbine engines, biomechanics, pipelines, defense, weaponry, and infrastructure. This program combines state-of-the-art probabilistic algorithms with general-purpose structural analysis and lifting methods to compute the probabilistic response and reliability of engineered structures. Uncertainties in load, material properties, geometry, boundary conditions, and initial conditions can be simulated. The structural analysis methods include non-linear finite-element methods, heat-transfer analysis, polymer/ceramic matrix composite analysis, monolithic (conventional metallic) materials life-prediction methodologies, boundary element methods, and user-written subroutines. Several probabilistic algorithms are available such as the advanced mean value method and the adaptive importance sampling method. NASA/NESSUS 6.2c is structured in a modular format with 15 elements.
COI Structural Analysis Presentation
Cline, Todd; Stahl, H. Philip (Technical Monitor)
2001-01-01
This report discusses the structural analysis of the Next Generation Space Telescope Mirror System Demonstrator (NMSD) developed by Composite Optics Incorporated (COI) in support of the Next Generation Space Telescope (NGST) project. The mirror was submitted to Marshall Space Flight Center (MSFC) for cryogenic testing and evaluation. Once at MSFC, the mirror was lowered to approximately 40 K and the optical surface distortions were measured. Alongside this experiment, an analytical model was developed and used to compare to the test results. A NASTRAN finite element model was provided by COI and a thermal model was developed from it. Using the thermal model, steady state nodal temperatures were calculated based on the predicted environment of the large cryogenic test chamber at MSFC. This temperature distribution was applied in the structural analysis to solve for the deflections of the optical surface. Finally, these deflections were submitted for optical analysis and comparison to the interferometer test data.
Kumar, A.; Alenkina, I. V.; Zakharova, A. P.; Oshtrakh, M. I.; Semionkin, V. A.
2015-04-01
A comparative study of monomeric soybean and lupin leghemoglobins in the oxy-form was carried out using Mössbauer spectroscopy with a high velocity resolution at 90 K. The 57Fe hyperfine parameters of measured spectra were evaluated and compared with possible structural differences in the heme Fe(II)-O 2 bond.
Energy Technology Data Exchange (ETDEWEB)
Kumar, A. [University of Delhi South Campus, Department of Biochemistry (India); Alenkina, I. V. [Ural Federal University, Department of Physical Techniques and Devices for Quality Control, Institute of Physics and Technology (Russian Federation); Zakharova, A. P. [Ural Federal University, Department of Experimental Physics, Institute of Physics and Technology (Russian Federation); Oshtrakh, M. I., E-mail: oshtrakh@gmail.com; Semionkin, V. A. [Ural Federal University, Department of Physical Techniques and Devices for Quality Control, Institute of Physics and Technology (Russian Federation)
2015-04-15
A comparative study of monomeric soybean and lupin leghemoglobins in the oxy-form was carried out using Mössbauer spectroscopy with a high velocity resolution at 90 K. The {sup 57}Fe hyperfine parameters of measured spectra were evaluated and compared with possible structural differences in the heme Fe(II)–O {sub 2} bond.
DEFF Research Database (Denmark)
Larsen, Michael Holm
1999-01-01
This note introduces the IDEF0 modelling language (semantics and syntax), and associated rules and techniques, for developing structured graphical representations of a system or enterprise. Use of this standard for IDEF0 permits the construction of models comprising system functions (activities...... that require a modelling technique for the analysis, development, re-engineering, integration, or acquisition of information systems; and incorporate a systems or enterprise modelling technique into a business process analysis or software engineering methodology.This note is a summary of the Standard...
Evolution of the quadrupole hyperfine interaction while milling a Si-HfO{sub 2} blend
Energy Technology Data Exchange (ETDEWEB)
Chain, C.Y., E-mail: yamil@fisica.unlp.edu.ar [Departamento de Fisica, Facultad de Ciencias Exactas, Universidad Nacional de La Plata (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina); Ferrari, S.; Damonte, L.C. [Departamento de Fisica, Facultad de Ciencias Exactas, Universidad Nacional de La Plata (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina); Martinez, J.A.; Pasquevich, A.F. [Departamento de Fisica, Facultad de Ciencias Exactas, Universidad Nacional de La Plata (Argentina); Comision de Investigaciones Cientificas de la Provincia de Buenos Aires (CIC-PBA) (Argentina)
2012-09-25
Highlights: Black-Right-Pointing-Pointer Perturbed angular correlations and X-ray diffraction studies in equimolar Si-HfO{sub 2}. Black-Right-Pointing-Pointer Mixture subjected to progressive mechanical milling and a final annealing. Black-Right-Pointing-Pointer Short milling distorts monoclinic hafnia to tetragonal forms. Black-Right-Pointing-Pointer Long milling forms hafnon precursor. Black-Right-Pointing-Pointer Moderate temperature annealing ends in hafnon. - Abstract: As HfO{sub 2} appears as a good candidate to replace SiO{sub 2} in Si complementary metal-oxide-semiconductor devices, a refined knowledge of the possible solid-state reactions between Si and HfO{sub 2} is valuable. Being the Perturbed Angular Correlations technique a very sensitive method to detect small changes in solid state, the goal of this work is to follow the different stages that occur while ball milling a blend Si-HfO{sub 2} by inspecting the hyperfine quadrupole interaction at Hf sites. The characterization is complemented by X-ray diffraction analysis. For comparison, a similar study on pure m-HfO{sub 2} is carried out. The results seem to reveal a gradual incorporation of Si in a tetragonal defective phase of hafnia with milling time. In addition, the formation of precursor arrays of the HfSiO{sub 4} structure takes place. After an annealing at 1000 Degree-Sign C an important amount of crystalline hafnon appears.
Hyperfine fields of Fe in Nd2Fe14BandSm2Fe17N3
Akai, Hisazumi; Ogura, Masako
2015-03-01
High saturation magnetization of rare-earth magnets originates from Fe and the strong magnetic anisotropy stems from f-states of rare-earth elements such as Nd and Sm. Therefore the hyperfine fields of both Fe and rare-earth provide us with important pieces of information: Fe NMR enable us to detect site dependence of the local magnetic moment and magnetic anisotropy (Fe sites also contribute to the magnetic anisotropy) while rare-earth NQR directly give the information of electric field gradients (EFG) that are related to the shape of the f-electron cloud as well as the EFG produced by ligands. In this study we focus on the hyperfine fields of materials used as permanent magnets, Nd2Fe14BandSm2Fe17N3 from theoretical points of view. The detailed electronic structure together with the hyperfine interactions are discussed on the basis of the first-principles calculation. In particular, the relations between the observed hyperfine fields and the magnetic properties are studies in detail. The effects of doping of those materials by other elements such as Dy and the effects of N adding in Sm2Fe17N3 will be discussed. This work was supported by Elements Strategy Initiative Center for Magnetic Materials Project, the Ministry of Education, Culture, Sports, Science and Technology, Japan.
Hyperfine field distributions in disordered Mn2CoSn and Mn2NiSn ...
Indian Academy of Sciences (India)
Unknown
Mössbauer studies using Sn-119 were carried out to investigate the hyperfine fields present at the Sn site in these alloys. The hyperfine field distribution in these alloys as well as X-ray studies point to the chemical disorder present in both alloys. Co-existence of a paramagnetic portion along with the magnetic hyperfine part.
Kinetic models in spin chemistry. 1. The hyperfine interaction
DEFF Research Database (Denmark)
Mojaza, M.; Pedersen, J. B.
2012-01-01
Kinetic models for quantum systems are quite popular due to their simplicity, although they are difficult to justify. We show that the transformation from quantum to kinetic description can be done exactly for the hyperfine interaction of one nuclei with arbitrary spin; more spins are described...
Cryogenic tunable microwave cavity at 13 GHz for hyperfine spectroscopy of antiprotonic helium
Sakaguchi, J; Hayano, R S; Ishikawa, T; Suzukia, K; Widmann, E; Yamaguchi, H; Caspers, Friedhelm; Eades, John; Horib, M; Barna, D; Horváth, D; Juhász, B; Torie, H A; Yamazakif, T
2004-01-01
For the precise measurement of the hyperfine structure of antiprotonic helium, microwave radiation of 12.9 GHz frequency is needed, tunable over . A cylindrical microwave cavity is used whose front and rear faces are meshed to allow the antiprotons and laser beams to enter. The cavity is embedded in a cryogenic helium gas target. Frequency tuning of with Q values of 2700?3000 was achieved using over-coupling and an external triple stub tuner. We also present Monte-Carlo simulations of the stopping distribution of antiprotons in the low-density helium gas using the GEANT4 package with modified energy loss routines.
Cryogenic Tunable Microwave Cavity at 13 GHz for Hyperfine Spectroscopy of Antiprotonic Helium
Barna, D; Eades, John; Gilg, H; Hayano, R S; Hori, Masaki; Horváth, M; Hayano, R S; Ishikawa, T; Juhász, B; Sakaguchi, J; Suzuki, K; Torii, H A; Widmann, E; Yamaguchi, H; Yamazaki, T
2004-01-01
For the precise measurement of the hyperfine structure of antiprotonic helium microwave radiation of 12.9 GHz frequency is needed, tunable over ±100 MHz. A cylindrical microwave cavity is used whose front and rear faces are meshed to allow the antiprotons and laser beams to enter. The cavity is embedded in a cryogenic helium gas target. Frequency tuning of 300 MHz with Q values of 2700-3000 was achieved using over-coupling and an external triple stub tuner. We also present Monte-Carlo simulations of the stopping distribution of antiprotons in the low-density helium gas using the GEANT4 package with modified energy loss routines.
Grachev, V. G.; Petersen, R. T.; Kokanyan, E. P.; Schirmer, O. F.; Malovichko, G. I.
2016-11-01
Measurements of the angular dependencies of Electron Nuclear Double Resonance (ENDOR) were used for the analysis of the substitution site and local environment of the dominant axial Fe3+ center in LiNbO3 crystals. All components of hyperfine and quadrupole tensors for several shells of Li and Nb nuclei were determined. Since the found isotropic part of the hyperfine interaction of the iron electrons with the Li nuclei was small, it was justified to approximate the anisotropic part by the dipole-dipole interaction of electron and nuclear spins. From the comparison of the calculated and observed ENDOR spectra of the Li nuclei, it was derived that the Fe3+ ion occupies a Li site but is shifted from the regular Li position by 0.009 nm toward the octahedral structural vacancy. There is no evidence for the presence of any charge compensators in the nearest Li and Nb shells, which indicates a distant mechanism of excess charge compensation. ENDOR of Nb nuclei shows that there is a large isotropic hyperfine interaction due to the significant indirect transferred interaction of Fe3+ with nearest off axis Nb nuclei via O2- and polarization of Nb inner electron shells.
The second spectrum of niobium: I. Accurate fine structure study of even-parity levels
Bouazza, Safa
2013-03-01
For the first time, a parametric analysis of the fine and hyperfine structure for even-parity levels of Nb II, involving 17 configurations, has been performed. The interpretation has been carried out based on a linked-parameter method of level-fitting calculations in a large multiconfiguration basis. The sets of fine structure parameters, the leading eigenvector percentages of levels, as well as their calculated magnetic Landé g-factors are newly given. Furthermore, we confirm on the whole the validity of the attributions to term designations, previously proposed. The single-electron hyperfine structure parameters are determined in their entirety for 93Nb II for the model space (4d + 5s)4 with a good accuracy and confirmed by ab initio calculations. Finally, a complete list of the predicted magnetic hyperfine structure constants A of all levels of this model space was generated.
Study of hyperfine parameters in Co-doped tin dioxide using PAC spectroscopy
Energy Technology Data Exchange (ETDEWEB)
Ramos, Juliana M.; Carbonari, Artur W.; Martucci, Thiago; Costa, Messias S.; Saxena, Rajendra N. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Vianden, R.; Kessler, P.; Geruschke, T.; Steffens, M., E-mail: vianden@hiskp.uni-bonn.d [Rheinische Friedrich-Wilhelms-Universitaet Bonn (HISKP- Bonn) (Germany). Helmholtz - Institut fuer Strahlen- und Kernphysik
2011-07-01
PAC technique has been used to measure the hyperfine interactions in nano-structured powder samples of semiconducting SnO{sub 2} doped with Co. The aim of this work is to compare the results of PAC measurements using two different techniques of introducing the radioactive {sup 111}In probe nuclei in the sample of SnO{sub 2} doped with Co. The perturbed gamma-gamma angular correlation (PAC) spectroscopy is used for the measurements of the magnetic hyperfine field (MHF) and the electric field gradient (EFG) at {sup 111}Cd sites in SnO{sub 2} doped with 1% and 2% Co. The measurement of EFG is used to study the defects introduced in the semiconductor material and also for the identification of different phases formed within the compound. The techniques utilized for introducing the radioactive {sup 111}In in the sample are the ion-implantation using radioactive ion beam of {sup 111}In and the chemical process in which {sup 111}InCl{sub 3} solution is added during the preparation of SnO{sub 2} doped with Co using sol gel method. The ion-implantation of {sup 111}In in SnO{sub 2} doped with Co was carried out using the University of Bonn ion-implanter with beam energy of 160 keV. The PAC measurements were carried out with four BaF{sub 2} detector gamma spectrometer in the temperature range of 10-295 K. The results show no significant difference in the values of hyperfine parameters. Both techniques show practically the same electric quadrupole interaction for the substitutional site. The results were compared with previous PAC and Moessbauer measurements of SnO{sub 2} powder samples using {sup 111}In-{sup 111}Cd probe. (author)
Indian Academy of Sciences (India)
This special issue of Sadhana is a collection of five papers selected from those presented at the Eighth National Seminar on Aerospace Structures (8th NASAS) organised by and held at the Indian Institute of Technology Madras, Chennai, on 9±10 October 1998. The Structures Panel of the Aeronautics Research and ...
Czech Academy of Sciences Publication Activity Database
Azamat, Dmitry; Badalyan, A. G.; Feng, D.H.; Lančok, Ján; Jastrabík, Lubomír; Dejneka, Alexandr; Baranov, P. G.; Yakovlev, D.R.; Bayer, M.
2017-01-01
Roč. 122, č. 24 (2017), s. 1-3, č. článku 243903. ISSN 0021-8979 R&D Projects: GA MŠk LO1409; GA ČR GA16-22092S Institutional support: RVO:68378271 Keywords : laser materials * magnetic resonance imaging * electron nuclear double resonance * hyperfine structure Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.068, year: 2016
Experimental and ab initio study of the hyperfine parameters of ZnFe {sub 2}O{sub 4} with defects
Energy Technology Data Exchange (ETDEWEB)
Quintero, J. Melo; Salcedo Rodríguez, K. L.; Pasquevich, G. A.; Zélis, P. Mendoza; Stewart, S. J., E-mail: stewart@fisica.unlp.edu.ar; Rodríguez Torres, C. E.; Errico, L. A. [Universidad Nacional de La Plata, IFLP-CCT- La Plata-CONICET and Departamento de Física, Facultad de Ciencias Exactas, C. C. 67 (Argentina)
2016-12-15
We present a combined Mössbauer and ab initio study on the influence of oxygen-vacancies on the hyperfine and magnetic properties of the ZnFe {sub 2}O{sub 4} spinel ferrite. Samples with different degree of oxygen-vacancies were obtained from zinc ferrite powder that was thermally treated at different temperatures up to 650 {sup ∘}C under vacuum.Theoretical calculations of the hyperfine parameters, magnetic moments and magnetic alignment have been carried out considering different defects such as oxygen vacancies and cation inversion. We show how theoretical and experimental approaches are complementary to characterize the local structure around Fe atoms and interpret the observed changes in the hyperfine parameters as the level of defects increases.
Baituti, Bernard
2017-11-01
Understanding the structure of oxygen evolving complex (OEC) fully still remains a challenge. Lately computational chemistry with the data from more detailed X-ray diffraction (XRD) OEC structure, has been used extensively in exploring the mechanisms of water oxidation in the OEC (Gatt et al., J. Photochem. Photobiol. B 104(1-2), 80-93 2011). Knowledge of the oxidation states is very crucial for understanding the core principles of catalysis by photosystem II (PSII) and catalytic mechanism of OEC. The present study involves simulation studies of the X-band continuous wave electron-magnetic resonance (CW-EPR) generated S 2 state signals, to investigate whether the data is in agreement with the four manganese ions in the OEC, being organised as a `3 + 1' (trimer plus one) model (Gatt et al., Angew. Chem. Int. Ed. 51, 12025-12028 2012; Petrie et al., Chem. A Eur. J. 21, 6780-6792 2015; Terrett et al., Chem. Commun. (Camb.) 50, 8-11 2014) or `dimer of dimers' model (Terrett et al. 2016). The question that still remains is how much does each Mn ion contribute to the " g2multiline" signal through its hyperfine interactions in OEC also to differentiate between the `high oxidation state (HOS)' and `low oxidation state (LOS)' paradigms? This is revealed in part by the structure of multiline (ML) signal studied in this project. Two possibilities have been proposed for the redox levels of the Mn ions within the catalytic cluster, the so called `HOS' and `LOS' paradigms (Gatt et al., J. Photochem. Photobiol. B 104(1-2), 80-93 2011). The method of data analysis involves numerical simulations of the experimental spectra on relevant models of the OEC cluster. The simulations of the X-band CW-EPR multiline spectra, revealed three manganese ions having hyperfine couplings with large anisotropy. These are most likely Mn III centres and these clearly support the `LOS' OEC paradigm model, with a mean oxidation of 3.25 in the S2 state. This is consistent with the earlier data by Jin et
Fuchs, Maurice Bernard
2016-01-01
Addressing structures, this book presents a classic discipline in a modern setting by combining illustrated examples with insights into the solutions. It is the fruit of the author’s many years of teaching the subject and of just as many years of research into the design of optimal structures. Although intended for an advanced level of instruction it has an undergraduate course at its core. Further, the book was written with the advantage of having massive computer power in the background, an aspect which changes the entire approach to many engineering disciplines and in particular to structures. This paradigm shift has dislodged the force (flexibility) method from its former prominence and paved the way for the displacement (stiffness) method, despite the multitude of linear equations it spawns. In this book, however, both methods are taught: the force method offers a perfect vehicle for understanding structural behavior, bearing in mind that it is the displacement method which does the heavy number crunch...
Kirova, T.; Cinins, A.; Efimov, D. K.; Bruvelis, M.; Miculis, K.; Bezuglov, N. N.; Auzinsh, M.; Ryabtsev, I. I.; Ekers, A.
2017-10-01
This paper is devoted to clarifying the implications of hyperfine (HF) interaction in the formation of adiabatic (i.e., "laser-dressed") states and their expression in the Autler-Townes (AT) spectra. We first use the Morris-Shore model [J. R. Morris and B. W. Shore, Phys. Rev. A 27, 906 (1983), 10.1103/PhysRevA.27.906] to illustrate how bright and dark states are formed in a simple reference system where closely spaced energy levels are coupled to a single state with a strong laser field with the respective Rabi frequency ΩS. We then expand the simulations to realistic hyperfine level systems in Na atoms for a more general case when non-negligible HF interaction can be treated as a perturbation in the total system Hamiltonian. A numerical analysis of the adiabatic states that are formed by coupling of the 3 p3 /2 and 4 d5 /2 states by the strong laser field and probed by a weak laser field on the 3 s1 /2-3 p3 /2 transition yielded two important conclusions. Firstly, the perturbation introduced by the HF interaction leads to the observation of what we term "chameleon" states—states that change their appearance in the AT spectrum, behaving as bright states at small to moderate ΩS, and fading from the spectrum similarly to dark states when ΩS is much larger than the HF splitting of the 3 p3 /2 state. Secondly, excitation by the probe field from two different HF levels of the ground state allows one to address orthogonal sets of adiabatic states; this enables, with appropriate choice of ΩS and the involved quantum states, a selective excitation of otherwise unresolved hyperfine levels in excited electronic states.
Electron spin dynamics due to hyperfine coupling in quantum dots
Woods, L. M.; Reinecke, T. L.; Rajagopal, A. K.
2008-02-01
The dynamics of spins in semiconductor quantum dots often is controlled by their hyperfine coupling to nuclear spins. We develop a straightforward and efficient approach to describe the dynamics and the effective decoherence of the electron spins due to hyperfine coupling in realistic quantum dots. Systems with a large number of nuclei and an arbitrary initial nuclear polarization for which the number of nuclei initially flipped over is much less than the total number of nuclei are treated. This treatment employs a pole approximation within a Schrödinger equation of motion for the state of the coupled electron and nuclear spin system, and it allows us to treat systems with arbitrary initial conditions. We find that typical time scales for the effective spin decoherence are on the order of tens of microseconds.
The first direct measurement of the hyperfine splitting in positronium
Energy Technology Data Exchange (ETDEWEB)
Suehara, T; Ishida, A; Namba, T; Asai, S; Kobayashi, T [Department of Physics and ICEPP, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 33-0033 (Japan); Saitot, H [Institute of Physics, University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, 153-8902 (Japan); Yoshida, M [High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki, 305-0801 (Japan); Idehara, T; Ogawa, I; Kobayashi, S [FIR Center, University of Fukui, 3-9-1 Bunkyo, Fukui, 910-8507 (Japan); Sabchevski, S, E-mail: suehara@icepp.s.u-tokyo.ac.j [Bulgarian Academy of Science, 1, 15 Noemvri Str., 1040 Sofia (Bulgaria)
2009-03-01
Positronium is an ideal system for the research of the QED. The hyperfine splitting of positronium (Ps-HFS) is sensitive to the new physics beyond the Standard Model via a vacuum oscillation. Previous experimental results of the Ps-HFS show 3.5 {sigma} discrepancy from the QED calculation, and it might be caused by uncertainties of the indirect method with static magnetic field and a few GHz RF. We developed a new direct measurement system of the Ps-HFS without static magnetic field, using a sub-THz gyrotron and a quasi-optical Fabry-Perot cavity. Status (hopefully the first result) of the direct positronium hyperfine transition observation will be presented.
Chiral Extrapolation of Lattice Data for Heavy Meson Hyperfine Splittings
Energy Technology Data Exchange (ETDEWEB)
X.-H. Guo; P.C. Tandy; A.W. Thomas
2006-03-01
We investigate the chiral extrapolation of the lattice data for the light-heavy meson hyperfine splittings D*-D and B*-B to the physical region for the light quark mass. The chiral loop corrections providing non-analytic behavior in m{sub {pi}} are consistent with chiral perturbation theory for heavy mesons. Since chiral loop corrections tend to decrease the already too low splittings obtained from linear extrapolation, we investigate two models to guide the form of the analytic background behavior: the constituent quark potential model, and the covariant model of QCD based on the ladder-rainbow truncation of the Dyson-Schwinger equations. The extrapolated hyperfine splittings remain clearly below the experimental values even allowing for the model dependence in the description of the analytic background.
Dephasing and hyperfine interaction in carbon nanotubes double quantum dots
DEFF Research Database (Denmark)
Reynoso, Andres Alejandro; Flensberg, Karsten
2012-01-01
We study theoretically the return probability experiment, which is used to measure the dephasing time T-2*, in a double quantum dot (DQD) in semiconducting carbon nanotubes with spin-orbit coupling and disorder-induced valley mixing. Dephasing is due to hyperfine interaction with the spins of the C...... with these for DQDs in clean nanotubes, whereas the disorder effect is always relevant when the magnetic field is perpendicular to the nanotube axis....
Hyperfine properties of La(V{sub 1−x}Fe{sub x})O{sub 3} compounds
Energy Technology Data Exchange (ETDEWEB)
Tupan, L. F. S.; Ivashita, F. F.; Barco, R. [Universidade Estadual de Maringá (Brazil); Hallouche, B. [Universidade de Santa Cruz do Sul (Brazil); Paesano, A., E-mail: paesano@wnet.com.br [Universidade Estadual de Maringá (Brazil)
2017-11-15
LaV{sub 1−x}Fe{sub x}O{sub 3} perovskites were synthesized in the vanadium-rich concentration range (i.e., x < 0.5) and characterized structurally and for the hyperfine properties of the iron nuclear probe. The aim of this investigation was to better understand the physical transformations that take place in the undoped compound (LaVO{sub 3}) at low temperatures. For that, X-ray diffraction analysis and, more extensively, {sup 57}Fe Mössbauer spectroscopy were applied. The results revealed that the LaV{sub 1}-xFexO{sub 3} vanadium-rich perovskites are orthorhombic at RT, and their lattice parameters decrease with increasing vanadium concentration. Lowering the temperature, the system becomes magnetic, with the iron moment freezing progressively. The presence of two magnetic subspectral components obtained at the lowest measurement temperatures suggests that the vanadium-rich samples, including LaVO{sub 3}, undergo a phase transition from an orthorhombic to a monoclinic structure at low temperatures.
The magnetic structure on the ground state of the equilateral triangular spin tube
Energy Technology Data Exchange (ETDEWEB)
Matsui, Kazuki, E-mail: k703861@eagle.sophia.ac.jp; Goto, Takayuki [Sophia University, Physics Division (Japan); Manaka, Hirotaka [Kagoshima University, Graduate School of Science and Engineering (Japan); Miura, Yoko [Suzuka National College of Technology (Japan)
2016-12-15
The ground state of the frustrated equilateral triangular spin tube CsCrF{sub 4} is still hidden behind a veil though NMR spectrum broaden into 2 T at low temperature. In order to investigate the spin structure in an ordered state by {sup 19}F-NMR, we have determined the anisotropic hyperfine coupling tensors for each three fluorine sites in the paramagnetic state. The measurement field was raised up to 10 T to achieve highest resolution. The preliminary analysis using the obtained hyperfine tensors has shown that the archetypal 120°-type structure in ab-plane does not accord with the NMR spectra of ordered state.
Energy Technology Data Exchange (ETDEWEB)
Chen, Yan-Cong; Liu, Jun-Liang; Chen, Xiao-Ming; Tong, Ming-Liang [Key Lab. of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry, Sun Yat-Sen Univ., Guangzhou (China); Wernsdorfer, Wolfgang [Institut Neel, CNRS and Universite Joseph Fournier, Grenoble (France); Institute of Nanotechnology, Karlsruhe Institute of Technology (Germany); Physikalisches Institut, Karlsruhe Institute of Technology (Germany); Liu, Dan; Chibotaru, Liviu F. [Theory of Nanomaterials Group and INPAC-Institute of Nanoscale Physics and Chemistry, Katholieke Universiteit Leuven (Belgium)
2017-04-24
An extremely rare non-Kramers holmium(III) single-ion magnet (SIM) is reported to be stabilized in the pentagonal-bipyramidal geometry by a phosphine oxide with a high energy barrier of 237(4) cm{sup -1}. The suppression of the quantum tunneling of magnetization (QTM) at zero field and the hyperfine structures originating from field-induced QTMs can be observed even from the field-dependent alternating-current magnetic susceptibility in addition to single-crystal hysteresis loops. These dramatic dynamics were attributed to the combination of the favorable crystal-field environment and the hyperfine interactions arising from {sup 165}Ho (I=7/2) with a natural abundance of 100 %. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)
Latent Structure Agreement Analysis
1989-11-01
general approach of Lazarsfeld and Henry [2]. More recently, we have used an EM algorithm 130] related to that described by Goodman [3] and Dawid and...inverting the information matrix [2]. Identifiability Lazarsfeld and Henry [2], Goodman [3], and others discuss identifiability of latent class models...and Irwig [43]. The fixed panel agreement model corresponds closely to traditional latent class analysis applications as described by Lazarsfeld and
Controlling the Rotational and Hyperfine State of Ultracold $^{87}$Rb$^{133}$Cs Molecules
Gregory, Philip D; Hutson, Jeremy M; Cornish, Simon L
2016-01-01
We demonstrate coherent control of both the rotational and hyperfine state of ultracold, chemically stable $^{87}$Rb$^{133}$Cs molecules with external microwave ?fields. We create a sample of ~2000 molecules in the lowest hyperfine level of the rovibronic ground state N = 0. We measure the transition frequencies to 8 different hyperfine levels of the N = 1 state at two magnetic fields ~23 G apart. We determine accurate values of rotational and hyperfine coupling constants that agree well with previous calculations. We observe Rabi oscillations on each transition, allowing complete population transfer to a selected hyperfine level of N = 1. Subsequent application of a second microwave pulse allows transfer of molecules back to a different hyperfine level of N = 0.
Belinskii, M. I.
1994-12-01
The dependences of the cluster g-factor, the effective hyperfine constants Ai and the hyperfine structure of the EPR signal on the exchange interaction were studied for the [Mn 3(III)Mn(IV)] and [Mn 3(IV)Mn(III)] clusters - possible prototypes of the Mn center of Photosystem II in the S 2 state. The mixing of the states with different S12 intermediate spins in the Heisenberg model HB = -2[ J12s1s2 + Jα( s1s3 + s1s4) + Jβ( s2s3 + s2s4) + J34s3s4] leads to essential exchange modification of the expectation values for each manganese ion. The exchange dependence of the Ki = / coefficients results in the exchange modification and reduction of the cluster g-factor. The / variations control also the values and signs of the effective hyperfine constants Ai. The Ai( Jtm) exchange dependences for the S = 1/2 ground state of the [Mn 3(III)Mn(IV)] and [Mn 3(IV)Mn(III)] clusters with complex structures were obtained in the framework of the general Heisenberg model of tetramer. The calculated hyperfine structures show a strong dependence on the total spin, intermediate spins and on the variation of the Heisenberg exchange parameters.
Nardali, Ş.; Ucun, F.; Karakaya, M.
2017-11-01
The optimized structures of some radical adducts of 5,5-dimethyl-1-pyrroline N-oxide were computed by different methods on ESR spectra. As trapped radicals, H, N3, NH2, CH3, CCl3, OOH in water and F, OH, CF3, CH2OH, OC2H5 in benzene solutions were used. The calculated isotropic hyperfine coupling constants of all the trapped radicals were compared with the corresponding experimental data. The hyperfine coupling constant due to the β proton of the nitroxide radical was seen to be consist with the McConnel's relation αβ = B 0 + B 1cos2θ and, to be effected with the opposite spin density of oxygen nucleus bonded to the nitrogen. It was concluded that in hyperfine calculations the DFT(B3PW91)/LanL2DZ level is superior computational quantum model relative to the used other level. Also, the study has been enriched by the computational of the optimized geometrical parameters, the hyper conjugative interaction energies, the atomic charges and spin densities for all the radical adducts.
Collapse Analysis of Timber Structures
DEFF Research Database (Denmark)
Kirkegaard, Poul Henning; Sørensen, John Dalsgaard
2008-01-01
A probabilistic based collapse analysis has been performed for a glulam frame structure supporting the roof over the main court in a Norwegian sports centre. The robustness analysis is based on the framework for robustness analysis introduced in the Danish Code of Practice for the Safety of Struc......A probabilistic based collapse analysis has been performed for a glulam frame structure supporting the roof over the main court in a Norwegian sports centre. The robustness analysis is based on the framework for robustness analysis introduced in the Danish Code of Practice for the Safety...... of Structures and a probabilistic modelling of the timber material proposed in the Probabilistic Model Code (PMC) of the Joint Committee on Structural Safety (JCSS). Due to the framework in the Danish Code the timber structure has to be evaluated with respect to the following criteria where at least one shall...... be fulfilled: a) demonstrating that those parts of the structure essential for the safety only have little sensitivity with respect to unintentional loads and defects, or b) demonstrating a load case with „removal of a limited part of the structure‟ in order to document that an extensive failure...
Structural, microstructural and hyperfine properties of nanocrystalline iron particles
Energy Technology Data Exchange (ETDEWEB)
Guittoum, A., E-mail: guittoum@yahoo.f [Centre de Recherche Nucleaire d' Alger, 2 Bd Frantz Fanon, BP 399 Alger-Gare, Alger (Algeria); Layadi, A. [Departement de Physique, Faculte des Sciences, Universite Ferhat Abbas, Setif 19000 (Algeria); Tafat, H. [Faculte de Mecanique et Genie des Procedes, USTHB de Bab Ezzouar (Algeria); Souami, N. [Centre de Recherche Nucleaire d' Alger, 2 Bd Frantz Fanon, BP 399 Alger-Gare, Alger (Algeria)
2010-03-15
Nanocrystalline Fe particles were successfully prepared by the mechanical milling process using a high-energy planetary ball mill. The physical properties of the samples were investigated as a function of the milling time, t (in the 0-54 h range) by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and Moessbauer spectroscopy. After 54 h of milling, the lattice parameter increases from 0.28620 (3) nm for the starting Fe powder to 0.28667 (3) nm, the grain size decreases from 110 to 13 nm, while the strain increases from 0.09% to 0.7%. The powder particle morphology was observed by SEM at different stages of milling. For t less than 24 h, the Moessbauer spectra are characterized by one sextet corresponding to the crystalline bcc Fe phase, while for t greater than 24 h, the iron particles exhibit a two-component Moessbauer spectrum due to the presence of two phases: the crystallites bcc Fe phase and the grain-boundary region. The appearance and the increase in intensity of the second sextet with t may indicate that the interfacial region effect increases with milling time due to the grain size reduction and a probable disordered state of the grain boundaries.
Hyperfine Structure and Exchange Narrowing of Paramagnetic Resonance
Townes, C. H.; Turkevich, J.
1950-01-01
Discussion of electronic paramagnetic resonance for the free radical á, á-diphenyl â-picryl hydrazyl as observed by its effect on the transmission of microwave through a TE{sub 01} cavity with a small amount of the free radical placed approximately on the axis of the cavity; the half-width of this resonance at half maximum absorption was 1.45 oersteds.
High precision hyperfine measurements in Bismuth challenge bound-state strong-field QED.
Ullmann, Johannes; Andelkovic, Zoran; Brandau, Carsten; Dax, Andreas; Geithner, Wolfgang; Geppert, Christopher; Gorges, Christian; Hammen, Michael; Hannen, Volker; Kaufmann, Simon; König, Kristian; Litvinov, Yuri A; Lochmann, Matthias; Maaß, Bernhard; Meisner, Johann; Murböck, Tobias; Sánchez, Rodolfo; Schmidt, Matthias; Schmidt, Stefan; Steck, Markus; Stöhlker, Thomas; Thompson, Richard C; Trageser, Christian; Vollbrecht, Jonas; Weinheimer, Christian; Nörtershäuser, Wilfried
2017-05-16
Electrons bound in highly charged heavy ions such as hydrogen-like bismuth 209 Bi 82+ experience electromagnetic fields that are a million times stronger than in light atoms. Measuring the wavelength of light emitted and absorbed by these ions is therefore a sensitive testing ground for quantum electrodynamical (QED) effects and especially the electron-nucleus interaction under such extreme conditions. However, insufficient knowledge of the nuclear structure has prevented a rigorous test of strong-field QED. Here we present a measurement of the so-called specific difference between the hyperfine splittings in hydrogen-like and lithium-like bismuth 209 Bi 82+,80+ with a precision that is improved by more than an order of magnitude. Even though this quantity is believed to be largely insensitive to nuclear structure and therefore the most decisive test of QED in the strong magnetic field regime, we find a 7-σ discrepancy compared with the theoretical prediction.
High precision hyperfine measurements in Bismuth challenge bound-state strong-field QED
Ullmann, Johannes; Andelkovic, Zoran; Brandau, Carsten; Dax, Andreas; Geithner, Wolfgang; Geppert, Christopher; Gorges, Christian; Hammen, Michael; Hannen, Volker; Kaufmann, Simon; König, Kristian; Litvinov, Yuri A.; Lochmann, Matthias; Maaß, Bernhard; Meisner, Johann; Murböck, Tobias; Sánchez, Rodolfo; Schmidt, Matthias; Schmidt, Stefan; Steck, Markus; Stöhlker, Thomas; Thompson, Richard C.; Trageser, Christian; Vollbrecht, Jonas; Weinheimer, Christian; Nörtershäuser, Wilfried
2017-05-01
Electrons bound in highly charged heavy ions such as hydrogen-like bismuth 209Bi82+ experience electromagnetic fields that are a million times stronger than in light atoms. Measuring the wavelength of light emitted and absorbed by these ions is therefore a sensitive testing ground for quantum electrodynamical (QED) effects and especially the electron-nucleus interaction under such extreme conditions. However, insufficient knowledge of the nuclear structure has prevented a rigorous test of strong-field QED. Here we present a measurement of the so-called specific difference between the hyperfine splittings in hydrogen-like and lithium-like bismuth 209Bi82+,80+ with a precision that is improved by more than an order of magnitude. Even though this quantity is believed to be largely insensitive to nuclear structure and therefore the most decisive test of QED in the strong magnetic field regime, we find a 7-σ discrepancy compared with the theoretical prediction.
Structural Analysis of Combustion Models
Tóth, J; Zsély, I
2013-01-01
Using ReactionKinetics, a Mathematica based package a few dozen detailed models for combustion of hydrogen, carbon monoxide and methanol are investigated. Essential structural characteristics are pulled out, and similarities and differences of the mechanisms are highlighted. These investigations can be used before or parallel with usual numerical investigations, such as pathway analysis, sensitivity analysis, parameter estimation, or simulation.
A study of platinum-supported catalysts through hyperfine interactions
Saitovitch, H.; Silva, P. R. J.; Rodriguez, A. M.; Weberszpil, J.; Passos, F. B.; Schmal, M.
1994-12-01
The effect of indium addition on alumina-supported platinum catalysts was investigated by measurements of hyperfine interactions. Via lime differential perturbed angular correlation spectroscopy (TDPAC) on111Cd, Pt/Al2O3 catalysts were studied in the flow of a heptane/H2 gas stream. The results indicate that some amount of indium sticks to platinum which is then dispersed on the support surface. The amount of In that is free from platinum is mobile under reaction conditions, being capable of diluting platinum particles and draining off coke precursors from the platinum surface.
A study of platinum-supported catalysts through hyperfine interactions
Energy Technology Data Exchange (ETDEWEB)
Saitovitch, H. (Centro Brasileiro de Pesquisas Fisicas (CBPF/CNPq), Rio de Janeiro, RJ (Brazil)); Silva, P.R.J. (Centro Brasileiro de Pesquisas Fisicas (CBPF/CNPq), Rio de Janeiro, RJ (Brazil)); Rodriguez, A.M. (Centro Brasileiro de Pesquisas Fisicas (CBPF/CNPq), Rio de Janeiro, RJ (Brazil)); Weberszpil, J. (Centro Brasileiro de Pesquisas Fisicas (CBPF/CNPq), Rio de Janeiro, RJ (Brazil)); Passos, F.B. (Dept. Eng. Quimica, Univ. Fed. Fluminense, Niteroi, RJ (Brazil)); Schmal, M. (COPPE/EQ, Univ. Fed. Rio de Janeiro, RJ (Brazil))
1994-05-01
The effect of indium addition on alumina-supported platinum catalysts was investigated by measurements of hyperfine interactions. Via time differential perturbed angular correlation spectroscopy (TDPAC) on [sup 111]Cd, Pt/Al[sub 2]O[sub 3] catalysts were studied in the flow of a heptane/H[sub 2] gas stream. The results indicate that some amount of indium sticks to platinum which is then dispersed on the support surface. The amount of In that is free from platinum is mobile under reaction conditions, being capable of diluting platinum particles and draining off coke precursors from the platinum surface. (orig.)
Spectra of charmed and bottom baryons with hyperfine interaction
Wang, Zhen-Yang; Qi, Jing-Juan; Guo, Xin-Heng; Wei, Ke-Wei
2017-09-01
Up to now, the excited charmed and bottom baryon states have still not been well studied experimentally or theoretically. In this paper, we predict the mass of , the only L = 0 baryon state which has not been observed, to be 6069.2 MeV. The spectra of charmed and bottom baryons with the orbital angular momentum L = 1 are studied in two popular constituent quark models, the Goldstone boson exchange (GBE) model and the one gluon exchange (OGE) hyperfine interaction model. Inserting the latest experimental data from the “Review of Particle Physics", we find that in the GBE model, there exist some multiplets (Σc(b), and Ωc(b)) in which the total spin of the three quarks in their lowest energy states is 3/2, but in the OGE model there is no such phenomenon. This is the most important difference between the GBE and OGE models. These results can be tested in the near future. We suggest more efforts to study the excited charmed and bottom baryons both theoretically and experimentally, not only for the abundance of baryon spectra, but also for determining which hyperfine interaction model best describes nature. Supported by National Natural Science Foundation of China (11175020, 11575023, U1204115)
Hyperfine anomalies in Fr: boundaries of the spherical single particle model
Zhang, J; Aubin, S; Behr, J A; Gomez, E; Gwinner, G; Orozco, L A; Pearson, M R; Sprouse, G D
2015-01-01
We have measured the hyperfine splitting of the $7P_{1/2}$ state at the 100 ppm level in Fr isotopes ($^{206g,206m, 207, 209, 213, 221}$Fr) near the closed neutron shell ($N$ = 126 in $^{213}$Fr). The measurements in five isotopes and a nuclear isomeric state of francium, combined with previous determinations of the $7S_{1/2}$ splittings, reveal the spatial distribution of the nuclear magnetization, i.e. the Bohr-Weisskopf effect. We compare our results with a simple shell model consisting of unpaired single valence nucleons orbiting a spherical nucleus, and find good agreement over a range of neutron-deficient isotopes ($^{207-213}$Fr). Also, we find near-constant proton anomalies for several even-$ N$ isotopes. This identifies a set of Fr isotopes whose nuclear structure can be understood well enough for the extraction of weak interaction parameters from parity non-conservation studies.
Hyperfine Anomalies in Fr: Boundaries of the Spherical Single Particle Model
Zhang, J.; Tandecki, M.; Collister, R.; Aubin, S.; Behr, J. A.; Gomez, E.; Gwinner, G.; Orozco, L. A.; Pearson, M. R.; Sprouse, G. D.; FrPNC Collaboration
2015-07-01
We have measured the hyperfine splitting of the 7 P1 /2 state at the 100 ppm level in Fr isotopes (206g,206m,207,209,213,221Fr) near the closed neutron shell (N =126 in 213Fr). The measurements in five isotopes and a nuclear isomeric state of francium, combined with previous determinations of the 7 S1 /2 splittings, reveal the spatial distribution of the nuclear magnetization, i.e., the Bohr-Weisskopf effect. We compare our results with a simple shell model consisting of unpaired single valence nucleons orbiting a spherical nucleus, and find good agreement over a range of neutron-deficient isotopes (207-213Fr). Also, we find near-constant proton anomalies for several even-N isotopes. This identifies a set of Fr isotopes whose nuclear structure can be understood well enough for the extraction of weak interaction parameters from parity nonconservation studies.
Calculation of Radiative Corrections to Hyperfine Splitting in p3/2 States
Energy Technology Data Exchange (ETDEWEB)
Sapirstein, J; Cheng, K T
2008-07-15
A recent calculation of the one-loop radiative correction to hyperfine splitting (hfs) of p{sub 1/2} states that includes binding corrections to all orders is extended to p{sub 3/2} states. Nuclear structure plays an essentially negligible role for such states, which is highly advantageous, as difficulties in controlling the Bohr-Weisskopf effect complicate the isolation of QED contributions for both s{sub 1/2} and p{sub 1/2} states. Three cases are studied. We first treat the hydrogen isoelectronic sequence, which is completely nonperturbative in Z{alpha} for high Z. Secondly the lowest lying p{sub 3/2} states of the neutral alkalis are treated, and finally lithium-like bismuth, where extensive theoretical and experimental studies of the hfs of 2s and 2p{sub 1/2} states have been made, is addressed.
Fine and hyperfine excitation of C2H by collisions with He at low temperature
Spielfiedel, A.; Feautrier, N.; Najar, F.; Ben Abdallah, D.; Dayou, F.; Senent, M. L.; Lique, F.
2012-04-01
Modelling of molecular emission from interstellar clouds requires the calculation of rate coefficients for excitation by collisions with the most abundant species. From a new, highly correlated, two-dimensional potential energy surface, rotational excitation of the C2H(X2Σ+) molecule by collision with He is investigated. State-to-state collisional excitation cross-sections between the 25 first fine structure levels of C2H are calculated for energies up to 800 cm-1 which yields after thermal averaging rate coefficients up to T= 100 K. The exact spin splitting of the energy levels is taken into account. The recoupling technique introduced by Alexander & Dagdigian allows us to deduce the corresponding temperature-dependent hyperfine state-to-state rate coefficients. Propensity rules are discussed.
Mössbauer studies of hyperfine fields in disordered Fe CrAl
Indian Academy of Sciences (India)
The paramagnetic part of the hyperfine field is explained in terms of the clustering of Cr atoms. Keywords. Mössbauer spectroscopy; disordered alloy; magnetic hyperfine fields. PACS Nos 75.50.Bb; 61.18.Fs. 1. Introduction. Heusler alloys are ternary alloys of stoichiometric composition bearing the general for- mula X2YZ.
Detection of the Direct Hyperfine Transition of Positronium Atoms using sub-THz High-power Radiation
Suehara, T.; Miyazaki, A.; Yamazaki, T; G. Akimoto; Ishida, A; NAMBA, T; Asai, S.; Kobayashi, T; Saito, H.(Institute of Physics, Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan); Yoshida, M.; IDEHARA, T; Ogawa, I.; Urushizaki, Y.; SABCHEVSKI, S
2010-01-01
Hyperfine splitting of positronium is an important parameter for particle physics. This paper gives experimental techniques and results of R&D studies of our experiment to observe direct hyperfine transition of ortho-positronium to para-positronium.
Kale, Y B; Tiwari, V B; Singh, S; Rawat, H S
2015-01-01
Narrow linewidth signals of Electromagnetically Induced Transparency (EIT) in the metastable 83Kr have been observed for the first time. Various hyperfine transitions in 4p55s[3/2]2 to 4p55p[5/2]3 manifolds of 83Kr have been identified through the experimentally observed EIT signals. Some unresolved or poorly resolved hyperfine transitions in saturated absorption spectroscopy (SAS) are clearly resolved in the present work. Using the spectral separation of these EIT identified hyperfine transitions, the magnetic hyperfine constant (A) and the electric quadrupole hyperfine constant (B) are determined with improved accuracy for 4p55s[3/2]2 and 4p55p[5/2]3 manifolds.
Structural Analysis of Communication Development.
Conville, Richard L.
This paper discusses the question of the legitimacy of applying structural analysis to actual human behavior and illustrates its legitimacy by using the reasoning in an essay by Paul Ricoeur. It then asks if the principles of communication development (obliqueness, exchange, and dying) derived from Helen Keller's experience of communication…
Golovko, V.V.; Phalet, T.; Delaure, B.; Beck, M.; Kozlov, V.Yu.; Coeck, S.; Wauters, F.; Herzog, P.; Tramm, Ch.; Zakoucky, D.; Venos, D.; Srnka, D.; Honusek, M.; Koster, U.; Severijns, N.
2010-01-01
Nuclear magnetic resonance (NMR/ON) measurements with beta- and gamma-ray detection have been performed on oriented Ag-104(g,m) nuclei with the NICOLE He-3-He-4 dilution refrigerator setup at ISOLDE/CERN. For Ag-104(g) (I-pi = 5(+)) the gamma-NMR/ON resonance signal was found at nu = 266.70(5) MHz. Combining this result with the known magnetic moment for this isotope, the magnetic hyperfine field of Ag impurities in an Fe host at low temperature (< 1 K) is found to be vertical bar B-hf(AgFe)vertical bar = 44.709(35) T. A detailed analysis of other relevant data available in the literature yields three more values for this hyperfine field. Averaging all four values yields a new and precise value for the hyperfine field of Ag in Fe; that is, vertical bar B-hf(AgFe)vertical bar = 44.692(30) T. For Ag-104(m) (I-pi = 2(+)), the anisotropy of the beta particles provided the NMR/ON resonance signal at nu = 627.7(4) MHz. Using the new value for the hyperfine field of Ag in Fe, this frequency corresponds to the mag...
Structural Analysis of Plate Based Tensegrity Structures
DEFF Research Database (Denmark)
Hald, Frederik; Kirkegaard, Poul Henning; Damkilde, Lars
2013-01-01
Plate tensegrity structures combine tension cables with a cross laminated timber plate and can then form e.g. a roof structure. The topology of plate tensegrity structures is investigated through a parametric investigation. Plate tensegrity structures are investigated, and a method...... for determination of the structures pre-stresses is used. A parametric investigation is performed to determine a more optimized form of the plate based tensegrity structure. Conclusions of the use of plate based tensegrity in civil engineering and further research areas are discussed....
Fine and hyperfine collisional excitation of C6H by He
Walker, Kyle M.; Lique, François; Dawes, Richard
2018-01-01
Hydrogenated carbon chains have been detected in interstellar and circumstellar media and accurate modelling of their abundances requires collisional excitation rate coefficients with the most abundant species. Among them, the C6H molecule is one of the most abundant towards many lines of sight. Hence, we determined fine and hyperfine-resolved rate coefficients for the excitation of C6H(X2Π) due to collisions with He. We present the first interaction potential energy surface for the C6H-He system, obtained from highly correlated ab initio calculations and characterized by a large anisotropy due to the length of the molecule. We performed dynamical calculations for transitions among the first fine structure levels (up to J = 30.5) of both spin-orbit manifolds of C6H using the close-coupling method, and rate coefficients are determined for temperatures ranging from 5 to 100 K. The largest rate coefficients for even ΔJ transitions conserve parity, while parity-breaking rate coefficients are favoured for odd ΔJ. Spin-orbit changing rate coefficients are several orders of magnitude lower than transitions within a single manifold. State-to-state hyperfine-resolved cross-sections for the first levels (up to J = 13.5) in the Ω = 3/2 spin-orbit manifold are deduced using recoupling techniques. Rate coefficients are obtained and the propensity rule ΔJ = ΔF is seen. These new data will help determine the abundance of C6H in astrophysical environments such as cold dense molecular clouds, star-forming regions and circumstellar envelopes, and will help in the interpretation of the puzzling C6H-/C6H abundance ratios deduced from observations.
Structural Analysis of Complex Networks
Dehmer, Matthias
2011-01-01
Filling a gap in literature, this self-contained book presents theoretical and application-oriented results that allow for a structural exploration of complex networks. The work focuses not only on classical graph-theoretic methods, but also demonstrates the usefulness of structural graph theory as a tool for solving interdisciplinary problems. Applications to biology, chemistry, linguistics, and data analysis are emphasized. The book is suitable for a broad, interdisciplinary readership of researchers, practitioners, and graduate students in discrete mathematics, statistics, computer science,
A source of antihydrogen for in-flight hyperfine spectroscopy
Kuroda, N; Murtagh, D J; Van Gorp, S; Nagata, Y; Diermaier, M; Federmann, S; Leali, M; Malbrunot, C; Mascagna, V; Massiczek, O; Michishio, K; Mizutani, T; Mohri, A; Nagahama, H; Ohtsuka, M; Radics, B; Sakurai, S; Sauerzopf, C; Suzuki, K; Tajima, M; Torii, H A; Venturelli, L; Wünschek, B; Zmeskal, J; Zurlo, N; Higaki, H; Kanai, Y; Lodi Rizzini, E; Nagashima, Y; Matsuda, Y; Widmann, E; Yamazaki, Y
2014-01-01
Antihydrogen, a positron bound to an antiproton, is the simplest antiatom. Its counterpart—hydrogen—is one of the most precisely investigated and best understood systems in physics research. High-resolution comparisons of both systems provide sensitive tests of CPT symmetry, which is the most fundamental symmetry in the Standard Model of elementary particle physics. Any measured difference would point to CPT violation and thus to new physics. Here we report the development of an antihydrogen source using a cusp trap for in-flight spectroscopy. A total of 80 antihydrogen atoms are unambiguously detected 2.7 m downstream of the production region, where perturbing residual magnetic fields are small. This is a major step towards precision spectroscopy of the ground-state hyperfine splitting of antihydrogen using Rabi-like beam spectroscopy.
Stereological analysis of spatial structures
DEFF Research Database (Denmark)
Hansen, Linda Vadgård
The thesis deals with stereological analysis of spatial structures. One area of focus has been to improve the precision of well-known stereological estimators by including information that is available via automatic image analysis. Furthermore, the thesis presents a stochastic model for star......-shaped three-dimensional objects using the radial function. It appears that the model is highly fleksiblel in the sense that it can be used to describe an object with arbitrary irregular surface. Results on the distribution of well-known local stereological volume estimators are provided....
Glycosphingolipid structural analysis and glycosphingolipidomics.
Levery, Steven B
2005-01-01
Sphingosines, or sphingoids, are a family of naturally occurring long-chain hydrocarbon derivatives sharing a common 1,3-dihydroxy-2-amino-backbone motif. The majority of sphingolipids, as their derivatives are collectively known, can be found in cell membranes in the form of amphiphilic conjugates, each composed of a polar head group attached to an N-acylated sphingoid, or ceramide. Glycosphingolipids (GSLs), which are the glycosides of either ceramide or myo-inositol-(1-O)-phosphoryl-(O-1)-ceramide, are a structurally and functionally diverse sphingolipid subclass; GSLs are ubiquitously distributed among all eukaryotic species and are found in some bacteria. Since GSLs are secondary metabolites, direct and comprehensive analysis (metabolomics) must be considered an essential complement to genomic and proteomic approaches for establishing the structural repertoire within an organism and deducing its possible functional roles. The glycosphingolipidome clearly comprises an important and extensive subset of both the glycome and the lipidome, but the complexities of GSL structure, biosynthesis, and function form the outlines of a considerable analytical problem, especially since their structural diversity confers by extension an enormous variability with respect to physicochemical properties. This chapter covers selected developments and applications of techniques in mass spectrometric (MS) that have contributed to GSL structural analysis and glycosphingolipidomics since 1990. Sections are included on basic characteristics of ionization and fragmentation of permethylated GSLs and of lithium-adducted nonderivatized GSLs under positive-ion electrospray ionization mass spectrometry (ESI-MS) and collision-induced mass spectrometry (CID-MS) conditions; on the analysis of sulfatides, mainly using negative-ion techniques; and on selected applications of ESI-MS and matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) to emerging GSL structural, functional
Study of the evolution of the hyperfine parameters in nanostructured Fe-Mn-Cu system
Energy Technology Data Exchange (ETDEWEB)
Mizrahi, M., E-mail: mizrahi@fisica.unlp.edu.ar; Cabrera, A. F.; Desimoni, J. [Facultad de Ciencias Exactas UNLP, Departamento de Fisica (Argentina)
2007-09-15
Hyperfine parameters evolution with the Cu content obtained by Moessbauer spectroscopy from mechanical milled (Fe{sub 79}Mn{sub 21}){sub 1-x}Cu{sub x} (x = 0.00 to 0.30) are presented. Results indicate that the Cu addition favors the formation of a FCC phase with two different magnetic states at room temperature. The trend of the hyperfine parameters with Cu composition suggests the incorporation of the Cu atoms at the regular FCC lattice sites.
Belinskii, M. I.
1994-12-01
The dependences of the cluster g-factor, the effective hyperfine constants A(sub i) and the hyperfine structure of the EPR signal on the exchange interaction were studied for the (Mn3(III)Mn(IV) and (Mn3(IV)Mn(III)) clusters - possible prototypes of the Mn center of Photosystem II in the S2 state. The mixing of the states with different S12 intermediate spins in the Heisenberg model H(sub B) = -2(J12 s1 s2 J-alpha(s1 s3 + s1 s4) + J-beta(s2 s3 + s2 s4) + J34 s3 s4) leads to essential exchange modification of the expectation values the average value of s(sub iz) for each manganese ion. The exchange dependence of the K(sub i) = the average value of s(sub iz)/the average value of S(sub Z) coefficients results in the exchange modification and reduction of the cluster g-factor. The average value of s(sub iz)/the average value of S(sub Z) variations control also the values and signs of the effective hyperfine constants A(sub i). The A(sub i)J(sub lm) exchange dependences for the S = 1/2 ground state of the (Mn2(III)Mn(IV) and (Mn3(IV)Mn(III)) clusters with complex structures were obtained in the framework of the general Heisenberg model of tetramer. The calculated hyperfine structures show a strong dependence on the total spin, intermediate spins and on the variation of the Heisenberg exchange parameters.
Hyperfine coupling constants from internally contracted multireference perturbation theory
Shiozaki, Toru
2016-01-01
We present an accurate method for calculating hyperfine coupling constants (HFCCs) based on the complete active space second-order perturbation theory (CASPT2) with full internal contraction. The HFCCs are computed as a first-order property using the relaxed CASPT2 spin-density matrix that takes into account orbital and configurational relaxation due to dynamical electron correlation. The first-order unrelaxed spin-density matrix is calculated from one- and two-body spin-free counterparts that are readily available in the CASPT2 nuclear gradient program [M. K. MacLeod and T. Shiozaki, J. Chem. Phys. 142, 051103 (2015)], whereas the second-order part is computed directly using the newly extended automatic code generator. The relaxation contribution is then calculated from the so-called Z-vectors that are available in the CASPT2 nuclear gradient program. Numerical results are presented for the CN and AlO radicals, for which the CASPT2 values are comparable (or, even superior in some cases) to the ones computed ...
Chen, Yu-Hui; Fernandez-Gonzalvo, Xavier; Horvath, Sebastian P.; Rakonjac, Jelena V.; Longdell, Jevon J.
2018-01-01
The hyperfine structure of the ground state of erbium-doped yttrium orthosilicate is analyzed with the use of electron paramagnetic resonance experiments in a tunable microwave resonator. This work was prompted by the disagreement between a recent measurement made at zero magnetic field and a previously published spin Hamiltonian. The ability to vary magnetic field strength, resonator frequency, and the orientation of our sample enabled us to monitor how the frequencies of hyperfine transitions change as a function of a vector magnetic field. We arrived at a different set of spin Hamiltonian parameters, which are also broadly consistent with the existing data. We discuss the reliability of our spin Hamiltonian parameters to make predictions outside the magnetic field and frequency regimes of our data. We also discuss why it proved to be difficult to determine spin Hamiltonian parameters for this material and present data collection strategies that improve the model reliability.
Soil Retaining Structures : Development of models for structural analysis
Bakker, K.J.
2000-01-01
The topic of this thesis is the development of models for the structural analysis of soil retaining structures. The soil retaining structures being looked at are; block revetments, flexible retaining walls and bored tunnels in soft soil. Within this context typical structural behavior of these
Robustness Analysis of Kinetic Structures
DEFF Research Database (Denmark)
Kirkegaard, Poul Henning; Sørensen, John Dalsgaard
2009-01-01
The present paper considers robustness of kinetic structures. Robustness of structures has obtained a renewed interest due to a much more frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure. Especially for these types of structural syst...... systems, it is of interest to investigate how robust the structures are, or what happens if a structural element is added to or removed from the original structure. The present paper discusses this issue for kinetic structures in architecture.......The present paper considers robustness of kinetic structures. Robustness of structures has obtained a renewed interest due to a much more frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure. Especially for these types of structural...
Khan, Sajid; Yazdani-Kachoei, M.; Jalali-Asadabadi, S.; Ahmad, Iftikhar
2017-12-01
In this paper, we explore the structural and magnetic properties as well as electric field gradient (EFG), hyperfine field (HFF) and quadrupole coupling constant in actinide digallide AcGa2 (Ac = U, Np, Pu) using LDA, GGA, LDA+U, GGA+U and hybrid functional with Wu-Cohen Generalized Gradient approximation HF-WC. Relativistic effects of the electrons are considered by including spin-orbit coupling. The comparison of the calculated structural parameters and magnetic properties with the available experimental results confirms the consistency and hence effectiveness of our theoretical tools. The calculated magnetic moments demonstrate that UGa2 and NpGa2 are ferromagnetic while PuGa2 is antiferromagnetic in nature. The EFG of AcGa2 is reported for the first time. The HFF, EFG and quadrupole coupling constant in AcGa2 (Ac = U, Np, Pu) are mainly originated from f-f and p-p contributions of Ac atom and p-p contribution of Ga atom.
Finkelstein, Ran; Cohen, Kobi; Jouault, Benoit; West, Ken; Pfeiffer, Loren N.; Vladimirova, Masha; Rapaport, Ronen
2017-08-01
We measure the spin-resolved transport of dipolar excitons in a biased GaAs double quantum well structure. From these measurements we extract both spin lifetime and mobility of the excitons. We find that below a temperature of 4.8 K there is a sharp increase in the spin lifetime of the excitons, together with a sharp reduction in their mobility. Below a critical power the spin lifetime increases with increasing mobility and density, while above the critical power the opposite trend is observed. We interpret this transition as evidence of the interplay between two different spin dephasing mechanisms: at low mobility the dephasing is dominated by the hyperfine interaction with the lattice nuclei spins, while at higher mobility the spin-orbit interaction dominates and a Dyakonov-Perel spin relaxation takes over. The excitation power and temperature regime where the hyperfine interaction induced spin dephasing is observed correlates with the regime where a dark dipolar quantum liquid was reported recently on a similar sample.
Risk Analysis of Marine Structures
DEFF Research Database (Denmark)
Hansen, Peter Friis
1998-01-01
Basic concepts of risk analysis is introduced. Formulation and analysis of fault and event trees are treated.......Basic concepts of risk analysis is introduced. Formulation and analysis of fault and event trees are treated....
Cox, S G
2001-01-01
An experimental investigation of the X sup 3 SIGMA sup - ground electronic state of the doubly charged molecule D sup 3 sup 5 Cl sup 2 sup + was performed using the Fast-lon-Beam/Laser-Beam-Spectrometer (FIBLBS), with a CO sub 2 infrared laser acting as the source of exciting radiation. Hyperfine resolved transitions between the nu=1->2 vibrational bands were observed for D sup 3 sup 5 Cl sup 2 sup +. The observed spectrum was analysed for transition frequencies, linewidths and relative signal intensities. A solenoid was designed, built and incorporated into the FIBLBS for the inducement of Zeeman splitting in the hyperfine structure of D sup 3 sup 5 Cl sup 2 sup +. The solenoid was used to investigate the splitting of a P branch hyperfine quartet over a variety of magnetic fields and was subsequently assigned unambiguously as a P sub Q sub sub 2 sub sub 3 (6) transition, with F quantum numbers 7/2, 9/2, 11/2 and 13/2
Analysis of the structure and Mössbauer study of the neodymium substitution in the Sr-hexaferrite
Energy Technology Data Exchange (ETDEWEB)
Pérez-Juache, T.J. [Departamento de Ingeniería de Procesos e Hidráulica, Universidad Autónoma Metropolitana-Iztapalapa, A.P. 55-534, 09340 México D.F., México (Mexico); Guerrero, A.L., E-mail: azdlobo@gmail.com [Facultad de Ciencias, UASLP, Salvador Nava Martínez, s/n. Zona Universitaria, 78290 San Luis Potosí S.L.P., México (Mexico); Cabal-Velarde, J.G. [Instituto Tecnológico Superior de Irapuato, Carretera Irapuato-Silao Km. 12.5. Irapuato, Guanajuato, México (Mexico); Mirabal-García, M. [Instituto de Física, UASLP, Dr. Manuel Nava No. 6. Zona Universitaria, 78290 San Luis Potosí S.L.P., México (Mexico); Palomares-Sánchez, S.A. [Facultad de Ciencias, UASLP, Salvador Nava Martínez, s/n. Zona Universitaria, 78290 San Luis Potosí S.L.P., México (Mexico); Matutes-Aquino, J.A. [Centro de Investigación en Materiales Avanzados, Ave. Miguel de Cervantes 120, Complejo Industrial Chihuahua, 31109 Chihuahua, Ch. México, México (Mexico)
2016-12-15
This work reads on the obtainment of the strontium hexaferrite substituted with neodymium in its pure phase using the solid state reaction method. The solubility of neodymium on the strontium hexaferrite was investigated according with the formula Sr{sub 1−x}Nd{sub x}Fe{sub 12}O{sub 19}, for x=0.00, 0.05, 0.10, 0.15, 0.20 and 0.25. Results indicate that neodymium is soluble in the hexaferrite until x=0.15. In samples with higher neodymium content there are traces of secondary phases. Analysis of magnetic and structural properties was performed in function of the neodymium content, always in its solubility range. From the structural properties, it was observed that the addition of a little neodymium quantity in the Sr-hexaferrite causes an important reduction of the unit cell volume. Also, magnetic properties are strongly linked to the structural behavior, in this case a trend to reduce the magnetization of the samples was detected when neodymium content increased, which can be explained in terms of fluctuations of the superexchange coupling conducted by the neodymium interactions with the structure. Mössbauer analysis was carried out in order to analyze the effects of the neodymium substitution on the hyperfine parameters, as well as to confirm the preferential site of the neodymium substitution in the Sr-hexaferrite.
In-beam measurement of the hydrogen hyperfine splitting and prospects for antihydrogen spectroscopy
Diermaier, M.; Jepsen, C. B.; Kolbinger, B.; Malbrunot, C.; Massiczek, O.; Sauerzopf, C.; Simon, M. C.; Zmeskal, J.; Widmann, E.
2017-06-01
Antihydrogen, the lightest atom consisting purely of antimatter, is an ideal laboratory to study the CPT symmetry by comparison with hydrogen. With respect to absolute precision, transitions within the ground-state hyperfine structure (GS-HFS) are most appealing by virtue of their small energy separation. ASACUSA proposed employing a beam of cold antihydrogen atoms in a Rabi-type experiment, to determine the GS-HFS in a field-free region. Here we present a measurement of the zero-field hydrogen GS-HFS using the spectroscopy apparatus of ASACUSA's antihydrogen experiment. The measured value of νHF=1,420,405,748.4(3.4) (1.6) Hz with a relative precision of 2.7 × 10-9 constitutes the most precise determination of this quantity in a beam and verifies the developed spectroscopy methods for the antihydrogen HFS experiment to the p.p.b. level. Together with the recently presented observation of antihydrogen atoms 2.7 m downstream of the production region, the prerequisites for a measurement with antihydrogen are now available within the ASACUSA collaboration.
Helium Pressure Shift of the Hyperfine Clock Transition in Hg-201(+)
Larigani, S. Taghavi; Burt, E. A.; Tjoelker, R. L.
2010-01-01
There are two stable odd isotopes of mercury with singly ionized hyperfine structure suitable for a microwave atomic clock: Hg-199(+) and Hg-201(+). We are investigating the viability of a trapped ion clock based on Hg-201(+) in a configuration that uses a buffer gas to increase ion loading efficiency and counter ion heating from rf trapping fields. Traditionally, either helium or neon is used as the buffer gas at approx. 10(exp -5) torr to confine mercury ions near room temperature. In addition to the buffer gas, other residual background gasses such as H2O, N2, O2, CO, CO2, and CH2 may be present in trace quantities. Collisions between trapped ions and buffer gas or background gas atoms/molecules produce a momentary shift of the ion clock transition frequency and constitute one of the largest systematic effects in this type of clock. Here we report an initial measurement of the He pressure shift in Hg-201(+) and compare this to Hg-199(+).
Free-Vibration Analysis of Structures
Gupta, K. K.
1984-01-01
Unified numerical procedure for free-vibration analysis of structures developed and incorporated into EIGSOL computer program. Dynamic response analysis of primary importance in design of wide range of practical structures such as space-craft, buildings, and rotating machineries. Procedure determines natural frequencies and associated modes in structural design.
Robustness Analysis of Kinetic Structures
DEFF Research Database (Denmark)
Kirkegaard, Poul Henning; Sørensen, John Dalsgaard
2009-01-01
Kinetic structures in architecture follows a new trend which is emerging in responsive architecture coined by Nicholas Negroponte when he proposed that architecture may benefit from the integration of computing power into built spaces and structures, and that better performing, more rational...
Towards the measurement of the ground-state hyperfine splitting of antihydrogen
Energy Technology Data Exchange (ETDEWEB)
Juhasz, Bertalan, E-mail: bertalan.juhasz@oeaw.ac.at [Austrian Academy of Sciences, Stefan Meyer Institute for Subatomic Physics (Austria)
2012-12-15
The ASACUSA collaboration at the Antiproton Decelerator of CERN is planning to measure the ground-state hyperfine splitting of antihydrogen using an atomic beam line, which will consist of a superconducting cusp trap as a source of partially polarized antihydrogen atoms, a radiofrequency spin-flip cavity, a superconducting sextupole magnet as spin analyser, and an antihydrogen detector. This will be a measurement of the antiproton magnetic moment, and also a test of the CPT invariance. Monte Carlo simulations predict that the antihydrogen ground-state hyperfine splitting can be determined with a relative precision of better than {approx} 10{sup - 6}. The first preliminary measurements of the hyperfine transitions will start in 2011.
Autodesk Robot Structural Analysis Professional 2016 essentials
Marsh, Ken
2016-01-01
Autodesk Robot Structural Analysis Professional 2016 - Essentials is an excellent introduction to the essential features, functions, and workflows of Autodesk Robot Structural Analysis Professional. Master the tools you will need to make Robot work for you: Go from zero to proficiency with this thorough and detailed introduction to the essential concepts and workflows of Robot Structural Analysis Professional 2016. - Demystify the interface - Manipulate and manage Robot tables like a pro - Learn how to use Robot's modeling tools - Master loading techniques - Harness Robot automated load combinations - Decipher simplified seismic loading - Discover workflows for steel and concrete design - Gain insights to help troubleshoot issues Guided exercises are provided to help cement fundamental concepts in Robot Structural Analysis and drive home key functions. Get up to speed quickly with this essential text and add Robot Structural Analysis Professional 2016 to your analysis and design toolbox. New in 2016: AWC-NDS ...
Hyperfine frequency shift of atomic hydrogen in the presence of helium buffer gas
Energy Technology Data Exchange (ETDEWEB)
Jochemsen, R.; Berlinsky, A.J. (British Columbia Univ., Vancouver (Canada). Dept. of Physics)
1982-02-01
A quantum mechanical thermal average is performed to obtain the temperature dependence of the hyperfine frequency shift (HFS) of hydrogen atoms in the presence of He buffer gas. The calculations are based on existing ab initio calculations of the hyperfine frequency shift as a function of internuclear separation and of the interatomic potential. We find that the HFS changes sign at fairly low temperature and has a small negative value at T = 1 K in agreement with recent measurements. The overall temperature dependence is shown to be quite sensitive to the interatomic potential.
Hyperfine fields and field gradients of thin films of face-centred-cubic Fe on Cu(001)
Gomez, J A
2002-01-01
The discrete variational method in density functional theory was employed to perform first-principles electronic structure calculations for embedded clusters representing thin films of face-centred-cubic Fe on a Cu(001) substrate. 3, 4 and 5 ML of Fe were investigated; the ferromagnetic and several types of antiferromagnetic spin configurations were considered. Layer-by-layer calculations of the contact and dipolar components of the magnetic hyperfine field are reported, as well as electric-field gradients at the surface and interface layers. Significant field gradients were found at the surfaces. Clusters modelling the interdiffusion of Fe and Cu between two layers at the interface were also investigated, to determine the effects on the properties.
Hyperfine-induced valley mixing and the spin-valley blockade in carbon-based quantum dots
Energy Technology Data Exchange (ETDEWEB)
Palyi, Andras; Burkard, Guido [Department of Physics, University Konstanz (Germany)
2010-07-01
Hyperfine interaction (HFI) in carbon nanotube and graphene quantum dots is due to the presence of {sup 13}C atoms. We theoretically show that in these structures the short-range nature of the HFI gives rise to a coupling between the valley degree of freedom of the electron and the nuclear spin, in addition to the usual electron spin-nuclear spin coupling. We predict that this property of the HFI affects the Pauli blockade transport in carbon-based double quantum dots. In particular, we show that transport is blocked only if both the spin and the valley degeneracies of the quantum dot levels are lifted, e.g., by an appropriately oriented magnetic field. The blockade is caused by four ''supertriplet'' states in the (1,1) charge configuration.
Energy Technology Data Exchange (ETDEWEB)
Michel, J. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires
1967-12-01
We have studied the hyperfine coupling in gadolinium-praseodymium alloys by specific heat measurements down to 0.3 K. In the first part we describe the apparatus used to perform our measurements. The second part is devoted to some theoretical considerations. We have studied in detail the case of praseodymium which is an exception in the rare earth series. The third part shows the results we have obtained. (author) [French] Nous avons etudie le couplage hyperfin d'alliages de gadolinium-praseodyme par des mesures de chaleur specifique jusqu'a 0.3 K. Dans la premiere partie de cette etude nous decrivons le dispositif experimental. La deuxieme partie est consacree a des considerations theoriques. Nous avons etudie en detail le cas du praseodyme qui est une exception dans la serie des terres rares. La troisieme partie est consacree aux resultats experimentaux. (auteur)
A topological analysis of plasma flow structures
Carreras, Benjamin A.; Llerena Rodríguez, Irene; García, Luis
2013-09-01
A new topological analysis of the plasma flow structures is presented for some pressure-gradient-driven turbulence results. The analysis is done by separating the structures into radial layers and studying each layer separately. This allows for the identification of flow cycles and flow filaments and the determination of the life of the cycles and length of the filaments.
FINITE ELEMENT ANALYSIS OF STRUCTURES
Directory of Open Access Journals (Sweden)
PECINGINA OLIMPIA-MIOARA
2015-05-01
Full Text Available The application of finite element method is analytical when solutions can not be applied for deeper study analyzes static, dynamic or other types of requirements in different points of the structures .In practice it is necessary to know the behavior of the structure or certain parts components of the machine under the influence of certain factors static and dynamic . The application of finite element in the optimization of components leads to economic growth , to increase reliability and durability organs studied, thus the machine itself.
Computer applications for engineering/structural analysis
Energy Technology Data Exchange (ETDEWEB)
Zaslawsky, M.; Samaddar, S.K.
1991-01-01
Analysts and organizations have a tendency to lock themselves into specific codes with the obvious consequences of not addressing the real problem and thus reaching the wrong conclusion. This paper discusses the role of the analyst in selecting computer codes. The participation and support of a computation division in modifying the source program, configuration management, and pre- and post-processing of codes are among the subjects discussed. Specific examples illustrating the computer code selection process are described in the following problem areas: soil structure interaction, structural analysis of nuclear reactors, analysis of waste tanks where fluid structure interaction is important, analysis of equipment, structure-structure interaction, analysis of the operation of the superconductor supercollider which includes friction and transient temperature, and 3D analysis of the 10-meter telescope being built in Hawaii. Validation and verification of computer codes and their impact on the selection process are also discussed.
Analysis of structures under uncertainties
da Cunha, Fabio; Chaves, Charlos; Degenhardt, Richard; Araujo, Franciso Cekio
2011-01-01
Theories of uncertainty are applied to a large range of fields, and they have a special interest on engineering, because of safety and risk concerns related to human lives. This concern is very high on aerospace applications, where safety is truly the most critical requirement. The most common approach to deal with uncertainties due to lack of knowledge and inherent variability on aerospace structures is through the application of safety factors, which are design margins against failure. Safe...
Analysis of Nonlinear Dynamic Structures
African Journals Online (AJOL)
Bheema
ISSN: 2220-184X. 2. METHODOLOGY. In this work MATLAB simulations based on two types of nonlinear FRF construction methods are used for the analysis of the nonlinear system. These are Harmonic Balance and Multiple. Input Multiple Output (MIMO) or Multiple Input Single Output (MISO) techniques. 2.1. FRF of ...
Nonlinear structural analysis using integrated force method
Indian Academy of Sciences (India)
developed and later these structures are analysed. The results of the analysis are compared with the results of the displacement method. It has been demonstrated that the integrated force method is equally viable and efficient as compared to the displacement method. Keywords. Finite element analysis; nonlinear analysis; ...
Towards Measuring the Ground State Hyperfine Splitting of Antihydrogen -- A Progress Report
Sauerzopf, C.
2016-06-20
We report the successful commissioning and testing of a dedicated field-ioniser chamber for measuring principal quantum number distributions in antihydrogen as part of the ASACUSA hyperfine spectroscopy apparatus. The new chamber is combined with a beam normalisation detector that consists of plastic scintillators and a retractable passivated implanted planar silicon (PIPS) detector.
ENDOR study of nitrogen hyperfine and quadrupole tensors in vanadyl porphyrins of heavy crude oil
Directory of Open Access Journals (Sweden)
Gracheva I.N., Gafurov M.R., Mamin G.V., Biktagirov T.B., Rodionov A.A., Galukhin A.V., Orlinskii S.B.
2016-11-01
Full Text Available We report the observation of pulsed electron-nuclear double resonance (ENDOR spectrum caused by interactions of the nitrogen nuclei 14N with the unpaired electron of the paramagnetic vanadyl complexes VO2+ of vanadyl porphyrins in natural crude oil. We provide detailed experimental and theoretical characterization of the nitrogen hyperfine and quadrupole tensors.
Hyperfine contributions to spin-exchange frequency shifts in the hydrogen maser
Verhaar, B.J.; Koelman, J.M.V.A.; Stoof, H.T.C.; Luiten, O.J.; Crampton, S.B.
1987-01-01
We have rigorously included hyperfine interactions during electron-spin-exchange collisions between ground state hydrogen atoms. We predict additional frequency shifts which are not compensated for by the usual methods of tuning maser cavities. These shifts are large compared to the potential
Towards measuring the ground state hyperfine splitting of antihydrogen – a progress report
Energy Technology Data Exchange (ETDEWEB)
Sauerzopf, C., E-mail: clemens.sauerzopf@oeaw.ac.at; Capon, A. A.; Diermaier, M. [Stefan Meyer Institute for subatomic physics, Austrian Academy of Sciences (Austria); Dupré, P. [Atomic Physics Laboratory, RIKEN (Japan); Higashi, Y. [University of Tokyo, Institute of Physics, Graduate School of Arts and Sciences (Japan); Kaga, C. [Hiroshima University, Graduate School of Advanced Sciences of Matter (Japan); Kolbinger, B. [Stefan Meyer Institute for subatomic physics, Austrian Academy of Sciences (Austria); Leali, M. [Università di Brescia, Dipartimento di Ingegneria dell’ Informazione (Italy); Lehner, S. [Stefan Meyer Institute for subatomic physics, Austrian Academy of Sciences (Austria); Rizzini, E. Lodi [Università di Brescia, Dipartimento di Ingegneria dell’ Informazione (Italy); Malbrunot, C. [Stefan Meyer Institute for subatomic physics, Austrian Academy of Sciences (Austria); Mascagna, V. [Università di Brescia, Dipartimento di Ingegneria dell’ Informazione (Italy); Massiczek, O. [Stefan Meyer Institute for subatomic physics, Austrian Academy of Sciences (Austria); Murtagh, D. J.; Nagata, Y.; Radics, B. [Atomic Physics Laboratory, RIKEN (Japan); Simon, M. C.; Suzuki, K. [Stefan Meyer Institute for subatomic physics, Austrian Academy of Sciences (Austria); Tajima, M. [University of Tokyo, Institute of Physics, Graduate School of Arts and Sciences (Japan); Ulmer, S. [Ulmer Initiative Research Unit, RIKEN (Japan); and others
2016-12-15
We report the successful commissioning and testing of a dedicated field-ioniser chamber for measuring principal quantum number distributions in antihydrogen as part of the ASACUSA hyperfine spectroscopy apparatus. The new chamber is combined with a beam normalisation detector that consists of plastic scintillators and a retractable passivated implanted planar silicon (PIPS) detector.
Relativistic DFT calculations of hyperfine coupling constants in the 5d hexafluorido complexes
DEFF Research Database (Denmark)
Haase, Pi Ariane Bresling; Repisky, Michal; Komorovsky, Stanislav
2017-01-01
ions. We find that both methods lead to very similar deviations from the experimental values for the [ReF6]2- complex, i.e. ~20% for the coupling constant using hybrid functionals. None of the methods is, however, able to reproduce the large anisotropy of the [ReF6]2- hyperfine tensor. For [IrF6...
Hyperfine Quenching of the 2s2p 3P0 State of Berylliumlike Ions
Energy Technology Data Exchange (ETDEWEB)
Cheng, K T; Chen, M H; Johnson, W R
2008-03-13
The hyperfine-induced 2s2p {sup 3}P{sub 0}-2s{sup 2} {sup 1}S{sub 0} transition rate for Be-like {sup 47}Ti{sup 18+} was recently measured in a storage-ring experiment by Schippers et al. [Phys. Rev. Lett. 98, 033001 (2007)]. The measured value of 0.56(3) s{sup -1} is almost 60% larger than the theoretical value of 0.356 s{sup -1} from a multiconfiguration Dirac-Fock calculation by Marques et al. [Phys. Rev. A 47, 929 (1993)]. In this work, we use a large-scale relativistic configuration-interaction method to calculate these hyperfine-induced rates for ions with Z = 6-92. Coherent hyperfine-quenching effects between the 2s2p {sup 1,3}P{sub 1} states are included in a perturbative as well as a radiation damping approach. Contrary to the claims of Marques et al., contributions from the {sup 1}P{sub 1} state are substantial and lead to a hyperfine-induced rate of 0.67 s{sup -1}, in better agreement with, though larger than, the measured value.
Structural analysis consultation using artificial intelligence
Melosh, R. J.; Marcal, P. V.; Berke, L.
1978-01-01
The primary goal of consultation is definition of the best strategy to deal with a structural engineering analysis objective. The knowledge base to meet the need is designed to identify the type of numerical analysis, the needed modeling detail, and specific analysis data required. Decisions are constructed on the basis of the data in the knowledge base - material behavior, relations between geometry and structural behavior, measures of the importance of time and temperature changes - and user supplied specifics characteristics of the spectrum of analysis types, the relation between accuracy and model detail on the structure, its mechanical loadings, and its temperature states. Existing software demonstrated the feasibility of the approach, encompassing the 36 analysis classes spanning nonlinear, temperature affected, incremental analyses which track the behavior of structural systems.
Analysis of MELCOR code structure
Energy Technology Data Exchange (ETDEWEB)
Kim, Dong Ha; Park, Sun Hee
2000-04-01
MELCOR executes in two parts. The first is a MELGEN program, in which most of the input is specified, processed, and checked. The second part of MELCOR is the MELCOR program itself, which advances the program through time based on the database generated by MELGEN and any additional MELCOR input. In particular, MELCOR execution involves two steps: (1) a setup mode in MEXSET, during which the database is read from the restart file and any additional input is processed, and (2) a run mode in MEXRUN, which advances the simulation through time, updating the time-dependent portion of the database each cycle. MELGEN and MELCOR share a structured and modular architecture that facilitates the incorporation of additional or altenative phenomenological modes. This structure consists of four primary levels: executive level, database manager routine level, package level, and utility level. MELCOR is composed of 24 different packages, each of which models a different portion of the accident phenomenology or program control. To identify the relation of the MELCOR subroutines with the packages, first two or three letters of the package's name are duplicated in the name of the subroutines. The same rule applies to the naming of the common block. Data flows and the specific subroutines in the MELGEN and MELCOR are analyzed by their functions according to the hierarchy of four levels for model improvement and replacement during the integral code development project.
Energy Technology Data Exchange (ETDEWEB)
Oshtrakh, M. I., E-mail: oshtrakh@gmail.com; Alenkina, I. V.; Semionkin, V. A. [Ural Federal University, Department of Physical Techniques and Devices for Quality Control, Institute of Physics and Technology (Russian Federation)
2016-12-15
Human liver ferritin and its iron-polymaltose pharmaceutical analogues Ferrum Lek, Maltofer® and Ferrifol® were studied using Mössbauer spectroscopy at 295 and 90 K. The Mössbauer spectra were fitted on the basis of a new model of heterogeneous iron core structure using five quadrupole doublets. These components were related to the corresponding more or less close-packed iron core layers/regions demonstrating some variations in the {sup 57}Fe hyperfine parameters for the studied samples.
Predictive structural dynamic network analysis.
Chen, Rong; Herskovits, Edward H
2015-04-30
Classifying individuals based on magnetic resonance data is an important task in neuroscience. Existing brain network-based methods to classify subjects analyze data from a cross-sectional study and these methods cannot classify subjects based on longitudinal data. We propose a network-based predictive modeling method to classify subjects based on longitudinal magnetic resonance data. Our method generates a dynamic Bayesian network model for each group which represents complex spatiotemporal interactions among brain regions, and then calculates a score representing that subject's deviation from expected network patterns. This network-derived score, along with other candidate predictors, are used to construct predictive models. We validated the proposed method based on simulated data and the Alzheimer's Disease Neuroimaging Initiative study. For the Alzheimer's Disease Neuroimaging Initiative study, we built a predictive model based on the baseline biomarker characterizing the baseline state and the network-based score which was constructed based on the state transition probability matrix. We found that this combined model achieved 0.86 accuracy, 0.85 sensitivity, and 0.87 specificity. For the Alzheimer's Disease Neuroimaging Initiative study, the model based on the baseline biomarkers achieved 0.77 accuracy. The accuracy of our model is significantly better than the model based on the baseline biomarkers (p-value=0.002). We have presented a method to classify subjects based on structural dynamic network model based scores. This method is of great importance to distinguish subjects based on structural network dynamics and the understanding of the network architecture of brain processes and disorders. Copyright © 2015 Elsevier B.V. All rights reserved.
Structural Dynamics and Data Analysis
Luthman, Briana L.
2013-01-01
This project consists of two parts, the first will be the post-flight analysis of data from a Delta IV launch vehicle, and the second will be a Finite Element Analysis of a CubeSat. Shock and vibration data was collected on WGS-5 (Wideband Global SATCOM- 5) which was launched on a Delta IV launch vehicle. Using CAM (CAlculation with Matrices) software, the data is to be plotted into Time History, Shock Response Spectrum, and SPL (Sound Pressure Level) curves. In this format the data is to be reviewed and compared to flight instrumentation data from previous flights of the same launch vehicle. This is done to ensure the current mission environments, such as shock, random vibration, and acoustics, are not out of family with existing flight experience. In family means the peaks on the SRS curve for WGS-5 are similar to the peaks from the previous flights and there are no major outliers. The curves from the data will then be compiled into a useful format so that is can be peer reviewed then presented before an engineering review board if required. Also, the reviewed data will be uploaded to the Engineering Review Board Information System (ERBIS) to archive. The second part of this project is conducting Finite Element Analysis of a CubeSat. In 2010, Merritt Island High School partnered with NASA to design, build and launch a CubeSat. The team is now called StangSat in honor of their mascot, the mustang. Over the past few years, the StangSat team has built a satellite and has now been manifested for flight on a SpaceX Falcon 9 launch in 2014. To prepare for the final launch, a test flight was conducted in Mojave, California. StangSat was launched on a Prospector 18D, a high altitude rocket made by Garvey Spacecraft Corporation, along with their sister satellite CP9 built by California Polytechnic University. However, StangSat was damaged during an off nominal landing and this project will give beneficial insights into what loads the CubeSat experienced during the crash
Dynamic analysis and design of offshore structures
Chandrasekaran, Srinivasan
2015-01-01
This book attempts to provide readers with an overall idea of various types of offshore platform geometries. It covers the various environmental loads encountered by these structures, a detailed description of the fundamentals of structural dynamics in a class-room style, estimate of damping in offshore structures and their applications in the preliminary analysis and design. Basic concepts of structural dynamics are emphasized through simple illustrative examples and exercises. Design methodologies and guidelines, which are FORM based concepts are explained through a few applied example structures. Each chapter also has tutorials and exercises for self-learning. A dedicated chapter on stochastic dynamics will help the students to extend the basic concepts of structural dynamics to this advanced domain of research. Hydrodynamic response of offshore structures with perforated members is one of the recent research applications, which is found to be one of the effective manner of retrofitting offshore structur...
Semantic Antinomies and Deep Structure Analysis
Zuber, Ryszard
1975-01-01
This article discusses constructions known as semantic antinomies, that is, the paradoxical results of false presuppositions, and how they can be dealt with by means of deep structure analysis. See FL 508 186 for availability. (CLK)
Comprehensive risk analysis for structure type selection.
2010-04-01
Optimization of bridge selection and design traditionally has been sought in terms of the finished structure. This study presents a : more comprehensive risk-based analysis that includes user costs and accidents during the construction phase. Costs f...
Robustness Analysis of Timber Truss Structure
DEFF Research Database (Denmark)
Rajčić, Vlatka; Čizmar, Dean; Kirkegaard, Poul Henning
2010-01-01
The present paper discusses robustness of structures in general and the robustness requirements given in the codes. Robustness of timber structures is also an issues as this is closely related to Working group 3 (Robustness of systems) of the COST E55 project. Finally, an example of a robustness ...... evaluation of a widespan timber truss structure is presented. This structure was built few years ago near Zagreb and has a span of 45m. Reliability analysis of the main members and the system is conducted and based on this a robustness analysis is preformed.......The present paper discusses robustness of structures in general and the robustness requirements given in the codes. Robustness of timber structures is also an issues as this is closely related to Working group 3 (Robustness of systems) of the COST E55 project. Finally, an example of a robustness...
Synthesis, crystal structure, thermal analysis and dielectric ...
Indian Academy of Sciences (India)
In both the materials, the crystal structure has been determined by X-ray single crystal analysis at room temperature (293 K). The compound structures consist of K + (or NH 4 + ) cations and double chains of CdCl 6 octahedra sharing one edge extending along b -axis. The mixture of KA + /NH 4 + cations are located ...
Using rhetorical structure in sentiment analysis
Hogenboom, Alexander; Frasincar, Flavius; de Jong, Franciska M.G.; Kaymak, Uzay
Automated sentiment analysis has become an active field of study with a broad applicability. One of the key open research issues lies in dealing with structural aspects of text when analyzing its conveyed sentiment. Recent work uses structural aspects of text in order to distinguish important text
Seismic analysis of nuclear power plant structures
Go, J. C.
1973-01-01
Primary structures for nuclear power plants are designed to resist expected earthquakes of the site. Two intensities are referred to as Operating Basis Earthquake and Design Basis Earthquake. These structures are required to accommodate these seismic loadings without loss of their functional integrity. Thus, no plastic yield is allowed. The application of NASTRAN in analyzing some of these seismic induced structural dynamic problems is described. NASTRAN, with some modifications, can be used to analyze most structures that are subjected to seismic loads. A brief review of the formulation of seismic-induced structural dynamics is also presented. Two typical structural problems were selected to illustrate the application of the various methods of seismic structural analysis by the NASTRAN system.
Structural Analysis Of Offshore Structures Exposed To Blast Loads
DEFF Research Database (Denmark)
Hansen, Hans Jakup; Thygesen, Ulf; Kristensen, Anders
2002-01-01
Numerical methods for simulations of blast loads and resulting structural response are investigated and compared to results obtained from tests. The CFD code EXSIM is used for the simulation of the blast load. This code provides a load profile wich is entered in the FEM analysis model....
Structural Analysis in a Conceptual Design Framework
Padula, Sharon L.; Robinson, Jay H.; Eldred, Lloyd B.
2012-01-01
Supersonic aircraft designers must shape the outer mold line of the aircraft to improve multiple objectives, such as mission performance, cruise efficiency, and sonic-boom signatures. Conceptual designers have demonstrated an ability to assess these objectives for a large number of candidate designs. Other critical objectives and constraints, such as weight, fuel volume, aeroelastic effects, and structural soundness, are more difficult to address during the conceptual design process. The present research adds both static structural analysis and sizing to an existing conceptual design framework. The ultimate goal is to include structural analysis in the multidisciplinary optimization of a supersonic aircraft. Progress towards that goal is discussed and demonstrated.
Impact analysis of composite aircraft structures
Pifko, Allan B.; Kushner, Alan S.
1993-01-01
The impact analysis of composite aircraft structures is discussed. Topics discussed include: background remarks on aircraft crashworthiness; comments on modeling strategies for crashworthiness simulation; initial study of simulation of progressive failure of an aircraft component constructed of composite material; and research direction in composite characterization for impact analysis.
Polarity Analysis of Texts using Discourse Structure
Heerschop, Bas; Goosen, Frank; Hogenboom, Alexander; Frasincar, Flavius; Kaymak, Uzay; de Jong, Franciska M.G.
2011-01-01
Sentiment analysis has applications in many areas and the exploration of its potential has only just begun. We propose Pathos, a framework which performs document sentiment analysis (partly) based on a document’s discourse structure. We hypothesize that by splitting a text into important and less
Structural Vibration Monitoring Using Cumulative Spectral Analysis
Directory of Open Access Journals (Sweden)
Satoru Goto
2013-01-01
Full Text Available This paper describes a resonance decay estimation for structural health monitoring in the presence of nonstationary vibrations. In structural health monitoring, the structure's frequency response and resonant decay characteristics are very important for understanding how the structure changes. Cumulative spectral analysis (CSA estimates the frequency decay by using the impulse response. However, measuring the impulse response of buildings is impractical due to the need to shake the building itself. In a previous study, we reported on system damping monitoring using cumulative harmonic analysis (CHA, which is based on CSA. The current study describes scale model experiments on estimating the hidden resonance decay under non-stationary noise conditions by using CSA for structural condition monitoring.
Mössbauer studies of hyperfine fields in disordered Fe
Indian Academy of Sciences (India)
Heusler-like alloy Fe2CrAl was prepared and studied. Structure determination was done by X-ray. The structure was found to conform to the B2 type. Magnetic hyperﬁne ﬁelds in this sample were studied by the Mössbauer effect. The Mössbauer spectra were recorded over a range of temperature from 40 to 296 K. The ...
Numerical Limit Analysis of Precast Concrete Structures
DEFF Research Database (Denmark)
Herfelt, Morten Andersen; Poulsen, Peter Noe; Hoang, Linh Cao
2016-01-01
Design and analysis of precast concrete structures in the ultimate limit state is largely done by simple analytical calculations and linear elastic finite element analysis, which necessarily leads to suboptimal designs. Numerical limit analysis provides a framework well suited for this task...... optimisation as well as material optimisation is given and a four-storey shear wall is analysed using load optimisation. The analysis yields a capacity more than three times larger than the design load for the critical load case, and the collapse mode and stress distribution are analysed. Finally, numerical...
Probing an Excited-State Atomic Transition Using Hyperfine Quantum Beat Spectroscopy
Wade, Christopher G; Keaveney, James; Adams, Charles S; Weatherill, Kevin J
2014-01-01
We describe a method to observe the dynamics of an excited-state transition in a room temperature atomic vapor using hyperfine quantum beats. Our experiment using cesium atoms consists of a pulsed excitation of the D2 transition, and continuous-wave driving of an excited-state transition from the 6P$_{3/2}$ state to the 7S$_{1/2}$ state. We observe quantum beats in the fluorescence from the 6P$_{3/2}$ state which are modified by the driving of the excited-state transition. The Fourier spectrum of the beat signal yields evidence of Autler-Townes splitting of the 6P$_{3/2}$, F = 5 hyperfine level and Rabi oscillations on the excited-state transition. A detailed model provides qualitative agreement with the data, giving insight to the physical processes involved.
Robust Two-Qubit Gates for Donors in Silicon Controlled by Hyperfine Interactions
Directory of Open Access Journals (Sweden)
Rachpon Kalra
2014-06-01
Full Text Available We present two strategies for performing two-qubit operations on the electron spins of an exchange-coupled pair of donors in silicon, using the ability to set the donor nuclear spins in arbitrary states. The effective magnetic detuning of the two electron qubits is provided by the hyperfine interaction when the two nuclei are prepared in opposite spin states. This can be exploited to switch SWAP operations on and off with modest tuning of the electron exchange interaction. Furthermore, the hyperfine detuning enables high-fidelity conditional rotation gates based on selective resonant excitation. The latter requires no dynamic tuning of the exchange interaction at all and offers a very attractive scheme to implement two-qubit logic gates under realistic experimental conditions.
Determination of hyperfine-induced transition rates from observations of a planetary nebula.
Brage, Tomas; Judge, Philip G; Proffitt, Charles R
2002-12-31
Observations of the planetary nebula NGC3918 made with the STIS instrument on the Hubble Space Telescope reveal the first unambiguous detection of a hyperfine-induced transition 2s2p 3P(o)(0)-->2s2 1S0 in the berylliumlike emission line spectrum of N IV at 1487.89 A. A nebular model allows us to confirm a transition rate of 4x10(-4) sec(-1)+/-33% for this line. The measurement represents the first independent confirmation of the transition rate of hyperfine-induced lines in low ionization stages, and it provides support for the techniques used to compute these transitions for the determination of very low densities and isotope ratios.
Directory of Open Access Journals (Sweden)
A. V. Gulay
2014-01-01
Full Text Available Ab-Initio simulation of electronic features of sensoring nanomaterials based on rare earth oxides has been made by the example of yttrium oxide. The simulation method for thin films of nanometer scale consisted in the simulation of the material layer of the thickness equal to unit crystal cell size has been proposed within the VASP simulation package. The atomic bond breakdown in the crystal along one of the coordinate axes is simulated by the increase of a distance between the atomic layers along this axis up to values at which the value of free energy is stabilized. It has been found that the valence and conductivity bands are not revealed explicitly and the band gap is not formed in the hyperfine rare earth oxide film (at the film thickness close to 1 nm. In fact the hyperfine rare earth oxide film loses dielectric properties which were exhibited clear enough in continuum.
Poggiali, F.; Cappellaro, P.; Fabbri, N.
2017-05-01
Precise knowledge of a quantum system's Hamiltonian is a critical pre-requisite for its use in many quantum information technologies. Here, we report a method for the precise characterization of the nonsecular part of the excited-state Hamiltonian of an electronic-nuclear spin system in diamond. The method relies on the investigation of the dynamic nuclear polarization mediated by the electronic spin, which is currently exploited as a primary tool for initializing nuclear qubits and performing enhanced nuclear magnetic resonance. By measuring the temporal evolution of the population of the ground-state hyperfine levels of a nitrogen-vacancy center, we obtain the first direct estimation of the excited-state transverse hyperfine coupling between its electronic and nitrogen nuclear spin. Our method could also be applied to other electron-nuclear spin systems, such as those related to defects in silicon carbide.
Object-Oriented Analysis, Structured Analysis, and Jackson System Development
Van Assche, F.; Wieringa, Roelf J.; Moulin, B.; Rolland, C
1991-01-01
Conceptual modeling is the activity of producing a conceptual model of an actual or desired version of a universe of discourse (UoD). In this paper, two methods of conceptual modeling are compared, structured analysis (SA) and object-oriented analysis (OOA). This is done by transforming a model
Data structures and algorithm analysis in Java
Shaffer, Clifford A
2011-01-01
With its focus on creating efficient data structures and algorithms, this comprehensive text helps readers understand how to select or design the tools that will best solve specific problems. It uses Java as the programming language and is suitable for second-year data structure courses and computer science courses in algorithm analysis. Techniques for representing data are presented within the context of assessing costs and benefits, promoting an understanding of the principles of algorithm analysis and the effects of a chosen physical medium. The text also explores tradeoff issues, familiari
Data structures and algorithm analysis in C++
Shaffer, Clifford A
2011-01-01
With its focus on creating efficient data structures and algorithms, this comprehensive text helps readers understand how to select or design the tools that will best solve specific problems. It uses Microsoft C++ as the programming language and is suitable for second-year data structure courses and computer science courses in algorithm analysis.Techniques for representing data are presented within the context of assessing costs and benefits, promoting an understanding of the principles of algorithm analysis and the effects of a chosen physical medium. The text also explores tradeoff issues, f
Hyperfine Level Interactions of Diamond Nitrogen Vacancy Ensembles Under Transverse Magnetic Fields
2015-10-06
excited and ground state cross- ings, which have been used for nuclear spin polarization to decrease resonance line width and increase resonance ...into ac- count the zero-field splitting, nuclear and electronic zee- man shifts, stark shifts, hyperfine splitting, and nuclear quadrupole effects: Hgs...describing interactions with local nuclear spins, Pgs is the nuclear electric quadrupole parameter, and Sk is the spin projection onto the k axis with
Magnetic field dependent intensity variation in the hyperfine split Rb D1 and D2 lines
Hu, Jianping; Ummal Momeen, M.
2017-11-01
We present the variation of intensity in Doppler-free hyperfine lines for rubidium atoms with the application of magnetic field. Different polarization configurations have been studied systematically with varying magnetic fields. There is a significant increase in the intensity variation with applied magnetic field related to different polarization configurations. These variations are explained with the theoretical calculations. The calculations are performed by adopting Nakayama's four level model with the varying magnetic field induced transition probability.
Hyperfine interactions of {beta}-emitter {sup 12}N in TiO{sub 2}
Energy Technology Data Exchange (ETDEWEB)
Maruyama, Yukiko [Osaka Univ., Toyonaka (Japan). Faculty of Science; Izumikawa, Takuji; Tanigaki, Minoru [and others
1997-03-01
Hyperfine interactions of {beta}-emitter {sup 12}N (I{sup {pi}} = 1{sup -}, T{sub 1/2} 11ms) in TiO{sub 2} has been studied. A {beta}-NMR spectrum on the polarized {sup 12}N implanted in TiO{sub 2} shows that {sup 12}N are located at two different sites and maintain about 100% of initial polarization. These are the first phenomena observed in ionic crystals. (author)
Improving transient analysis technology for aircraft structures
Melosh, R. J.; Chargin, Mladen
1989-01-01
Aircraft dynamic analyses are demanding of computer simulation capabilities. The modeling complexities of semi-monocoque construction, irregular geometry, high-performance materials, and high-accuracy analysis are present. At issue are the safety of the passengers and the integrity of the structure for a wide variety of flight-operating and emergency conditions. The technology which supports engineering of aircraft structures using computer simulation is examined. Available computer support is briefly described and improvement of accuracy and efficiency are recommended. Improved accuracy of simulation will lead to a more economical structure. Improved efficiency will result in lowering development time and expense.
MBS Analysis Of Kinetic Structures Using ADAMS
DEFF Research Database (Denmark)
Kirkegaard, Poul Henning; Nielsen, Søren R.K.
2009-01-01
-called multibody system (MBS) formalism. The present paper considers MBS modeling of kinetic architectural structures using the software packages ADAMS. As a result, it is found that symbolic MBS simulation tools facilitate a useful evaluation environment for MBS users during a design phase of responsive kinetic......The present paper considers multibody system (MBS) analysis of kinetic structures using the software package ADAMS. Deployable, foldable, expandable and reconfigurable kinetic structures can provide a change in the geometric morphology of the envelope by contributing to making it adaptable to e...
RNA Secondary Structure Analysis Using RNAstructure.
Mathews, David H
2014-06-17
RNAstructure is a user-friendly program for the prediction and analysis of RNA secondary structure. It is available as a Web server, as a program with a graphical user interface, or as a set of command-line tools. The programs are available for Microsoft Windows, Macintosh OS X, or Linux. This unit provides protocols for RNA secondary structure prediction (using the Web server or the graphical user interface) and prediction of high-affinity oligonucleotide biding sites to a structured RNA target (using the graphical user interface). Copyright © 2014 John Wiley & Sons, Inc.
Samokhvalov, V; Dietrich, M; Schneider, F; Tiginyanu, I M; Tsurkan, V; Unterricker, S
2003-01-01
The semiconducting ferromagnetic spinel compounds CdCr//2Se //4, CdCr //2S//4, HgCr//2Se//4 and CuCr//2Se//4 (metallic) were investigated by the perturbed angular correlations (PAC) method with the radioactive probes **1**1**1In, **1**1**1**mCd, **1**1**1Ag, **1**1**7Cd, **1**9**9**mHg and **7**7Br. The probes were implanted at the ISOLDE on-line separator (CERN-Geneva) into single crystals. From the time dependence of the PAC spectra and the measured hyperfine interaction parameters: electric field gradient and magnetic hyperfine field, the probe positions and the thermal behavior of the probes could be determined. Cd, Ag and Hg are substituted at the A-site, In at the A- and B-site in the semiconducting compounds and Br at the anion position. Electric and magnetic hyperfine fields were used as test quantities for theoretical charge and spin density distributions of LAPW calculations (WIEN97).
Energy Technology Data Exchange (ETDEWEB)
Silva, Andreia dos Santos; Carbonari, Artur Wilson; Lapolli, Andre Luis; Saxena, Rajendra Narain [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Saitovitch, Henrique, E-mail: asilva@usp.br [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)
2013-07-01
Perturbed γγ angular correlations (PAC) spectroscopy has been used to study the DNA nitrogenous bases (adenine, cytosine, guanine, thymine), using {sup 111}In→{sup 111}Cd and {sup 111m}Cd→{sup 111}Cd probe nuclei. One of the advantages of applying PAC technique to biological molecules is that the experiments can be carried out on molecules in aqueous solution [1], approaching the function of molecules under conditions that are close to in vivo conditions. The measurements were carried out for DNA nitrogenous bases molecules at 295 K and 77 K in order to investigate dynamic and static hyperfine interactions, respectively. The interpretation of the results was based on the measurements of dynamic interaction characterized by the decay constant from which valuable information on the macroscopic behavior of the molecules was obtained [2; 3]. On the other hand, PAC measurements at low temperature showed interaction frequency (ν{sub Q}), asymmetry parameter (η) and the distribution of the quadrupole frequency (δ). These parameters provide a local microscopic description of the chemical environment in the neighborhood of the probe nuclei. Results showed differences in the hyperfine interactions of probe nuclei bound to the studied biomolecules. Such differences were observed by variations in the hyperfine parameters, which depended on the type of biomolecule and the results also showed that the probe nuclei bounded at the molecules in some cases and at others did not. (author)
Theoretical Analysis of Polarized Structure Functions
Altarelli, Guido; Forte, Stefano; Ridolfi, G
1998-01-01
We review the analysis of polarized structure function data using perturbative QCD at next-to-leading order. We use the most recent experimental data to obtain updated results for polarized parton distributions, first moments and the strong coupling. We also discuss several theoretical issues involved in this analysis and in the interpretation of its results. Finally, we compare our results with other similar analyses in the recent literature.
Limit analysis of solid reinforced concrete structures
DEFF Research Database (Denmark)
Larsen, Kasper Paaske
2009-01-01
element for lower bound analysis of reinforced concrete structures is presented. The method defines the stress state at a point within the solid as a combination of concrete- and reinforcement stresses and yield criterions are applied to the stress components separately. This method allows for orthotropic...
Structural and functional analysis of rice genome
Indian Academy of Sciences (India)
Home; Journals; Journal of Genetics; Volume 83; Issue 1. Structural and functional analysis of rice genome ... Abstract. Rice is an excellent system for plant genomics as it represents a modest size genome of 430 Mb. It feeds more than half the population of the world. Draft sequences of the rice genome, derived by ...
Term Structure Analysis with Big Data
DEFF Research Database (Denmark)
Andreasen, Martin Møller; Christensen, Jens H.E.; Rudebusch, Glenn D.
Analysis of the term structure of interest rates almost always takes a two-step approach. First, actual bond prices are summarized by interpolated synthetic zero-coupon yields, and second, a small set of these yields are used as the source data for further empirical examination. In contrast, we...
Numerical Limit Analysis of Precast Concrete Structures
DEFF Research Database (Denmark)
Herfelt, Morten Andersen
. The strength and efficiency of the presented framework are demonstrated by two real size examples, a two-dimensional precast shear wall and a three-dimensional precast concrete stairwell. The analysis shows that the framework is capable of modelling complex precast concrete structures efficiently. Moreover......Precast concrete elements are widely used in the construction industry as they provide a number of advantages over the conventional in-situ cast concrete structures. Joints cast on the construction site are needed to connect the precast elements, which poses several challenges. Moreover....... The scope is to be able to model entire precast concrete structures while accounting for the local behaviour of the joints. The in-situ cast joints are crucial to the capacity of precast concrete structures, however, the behaviour of joints is in practice assessed by simple, empirical design formulas...
Analysis of aircraft impact to concrete structures
Energy Technology Data Exchange (ETDEWEB)
Arros, Jorma [MMI Engineering, 475, 14th Street, Oakland, CA 94612 (United States)]. E-mail: jarros@mmiengineering.com; Doumbalski, Nikolay [MMI Engineering, 475, 14th Street, Oakland, CA 94612 (United States)
2007-07-15
Analysis of aircraft impact to nuclear power plant structures is discussed utilizing a simplified model of a 'fictitious nuclear building' to perform analyses using LS-DYNA software, representing the loading: (i) by the Riera force history method and (ii) by modeling the crash by impacting a model of a plane similar to Boeing 747-400 to the structure (i.e., 'missile-target interaction method'). Points discussed include: (1) comparison of shock loading within the building as obtained from the Riera force history analysis versus from the missile-target interaction analysis, (2) sensitivity of the results on the assumed Riera force loading area, (3) linear versus nonlinear modeling and (4) on failure criteria.
Economic Evaluation of Computerized Structural Analysis
Fortin, P. E.
1985-01-01
This completed effort involved a technical and economic study of the capabilities of computer programs in the area of structural analysis. The applicability of the programs to NASA projects and to other users was studied. The applications in other industries was explored including both research and development and applied areas. The costs of several alternative analysis programs were compared. A literature search covered applicable technical literature including journals, trade publications and books. In addition to the literature search, several commercial companies that have developed computerized structural analysis programs were contacted and their technical brochures reviewed. These programs include SDRC I-DEAS, MSC/NASTRAN, SCADA, SUPERSAP, NISA/DISPLAY, STAAD-III, MICAS, GTSTRUDL, and STARS. These programs were briefly reviewed as applicable to NASA projects.
Hyperfine interactions at europium sites in oxide glasses
Concas, G.; Congiu, F.; Muntoni, C.; Bettinelli, M.; Speghini, A.
1996-03-01
The shape of the γ resonance absorption peak of the Eu3+ ion in a disordered structure was investigated in some phosphate, borate, and silicate glasses by using 151Eu Mössbauer spectroscopy. The quality of the fits was tested by using the Durbin-Watson d statistics. The observed full width at half maximum of the peak was resolved in a contribution of the broadening and a contribution of the quadrupole splitting, due to the distortion of the Eu site compared to a cubic symmetry. The Eu-O bond was found to have a covalent admixture with 6s character. The axial component of the electric-field gradient at the Eu site was found to be correlated with the optical basicity of the glass.
Structural Loads Analysis for Wave Energy Converters
Energy Technology Data Exchange (ETDEWEB)
van Rij, Jennifer A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Yu, Yi-Hsiang [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Guo, Yi [National Renewable Energy Laboratory (NREL), Golden, CO (United States)
2017-06-03
This study explores and verifies the generalized body-modes method for evaluating the structural loads on a wave energy converter (WEC). Historically, WEC design methodologies have focused primarily on accurately evaluating hydrodynamic loads, while methodologies for evaluating structural loads have yet to be fully considered and incorporated into the WEC design process. As wave energy technologies continue to advance, however, it has become increasingly evident that an accurate evaluation of the structural loads will enable an optimized structural design, as well as the potential utilization of composites and flexible materials, and hence reduce WEC costs. Although there are many computational fluid dynamics, structural analyses and fluid-structure-interaction (FSI) codes available, the application of these codes is typically too computationally intensive to be practical in the early stages of the WEC design process. The generalized body-modes method, however, is a reduced order, linearized, frequency-domain FSI approach, performed in conjunction with the linear hydrodynamic analysis, with computation times that could realistically be incorporated into the WEC design process.
Reliability Analysis of Elasto-Plastic Structures
DEFF Research Database (Denmark)
Thoft-Christensen, Palle; Sørensen, John Dalsgaard
1984-01-01
. Failure of this type of system is defined either as formation of a mechanism or by failure of a prescribed number of elements. In the first case failure is independent of the order in which the elements fail, but this is not so by the second definition. The reliability analysis consists of two parts...... are described and the two definitions of failure can be used by the first formulation, but only the failure definition based on formation of a mechanism by the second formulation. The second part of the reliability analysis is an estimate of the failure probability for the structure on the basis...
EURO AREA FISCAL STRUCTURES. A MULTIVARIATE ANALYSIS
Directory of Open Access Journals (Sweden)
HURDUZEU Gheorghe
2014-07-01
taxes on income of corporations and taxes on income of individuals and households and other current taxes. Actual social contributions were also split into employer’s actual contributions, employee’s social contributions and social contributions of self- and non-employed persons. As the primary data analysis revealed many differences between Euro Area member states, but also similarities concerning various fiscal aggregates, we completed the analysis through multidimensional analysis, with the aims of classifying Euro Area member states into subgroups with similar fiscal structures. Taking into consideration the above mentioned variables, we used cluster analysis in order to determine which member states have similar fiscal structures and which are the main similarities that characterize Euro Area in this respect.
Raman transitions between hyperfine clock states in a magnetic trap
Naber, J B; Hubert, T; Spreeuw, R J C
2016-01-01
We present our experimental investigation of an optical Raman transition between the magnetic clock states of $^{87}$Rb in an atom chip magnetic trap. The transfer of atomic population is induced by a pair of diode lasers which couple the two clock states off-resonantly to an intermediate state manifold. This transition is subject to destructive interference of two excitation paths, which leads to a reduction of the effective two-photon Rabi-frequency. Furthermore, we find that the transition frequency is highly sensitive to the intensity ratio of the diode lasers. Our results are well described in terms of light shifts in the multi-level structure of $^{87}$Rb. The differential light shifts vanish at an optimal intensity ratio, which we observe as a narrowing of the transition linewidth. We also observe the temporal dynamics of the population transfer and find good agreement with a model based on the system's master equation and a Gaussian laser beam profile. Finally, we identify several sources of decoheren...
Structure analysis for plane geometry figures
Feng, Tianxiao; Lu, Xiaoqing; Liu, Lu; Li, Keqiang; Tang, Zhi
2013-12-01
As there are increasing numbers of digital documents for education purpose, we realize that there is not a retrieval application for mathematic plane geometry images. In this paper, we propose a method for retrieving plane geometry figures (PGFs), which often appear in geometry books and digital documents. First, detecting algorithms are applied to detect common basic geometry shapes from a PGF image. Based on all basic shapes, we analyze the structural relationships between two basic shapes and combine some of them to a compound shape to build the PGF descriptor. Afterwards, we apply matching function to retrieve candidate PGF images with ranking. The great contribution of the paper is that we propose a structure analysis method to better describe the spatial relationships in such image composed of many overlapped shapes. Experimental results demonstrate that our analysis method and shape descriptor can obtain good retrieval results with relatively high effectiveness and efficiency.
A Structural Analysis of European Union Economy
Directory of Open Access Journals (Sweden)
Liliana DUGULEANĂ
2016-09-01
Full Text Available Based on the input-output analysis, the paper characterizes the structure of European economy in 2010 and 2011, on six main economic sectors. The sectoral structures of backward and forward linkages, and their absolute effects starting from the final demand, were compared with the real structures of sectors output, sectoral imports, sectoral value added, in 2011 face to 2010. The changes in final demand and in sectoral output can be analyzed in the propagation processes of the inter-sectoral economic flows, and allow us to know the behavior at macroeconomic level of European economy. The common economic policies at European level can be undertaken to keep the equilibrium between different sectors, to stimulate the sectors with high levels of productivity, to ensure the efficiency of using the resources, and the sustainability of economic development, which are the purposes of a smart development.
Numerical Limit Analysis of Reinforced Concrete Structures
DEFF Research Database (Denmark)
Larsen, Kasper Paaske
limit state analysis problems. The work focuses on determination of the load bearing capacity of reinforced concrete structures by employing the lower bound theorem and a finite element method using equilibrium elements is developed. The recent year’s development within the field of convex optimization...... is applied to solve the limit state problems. Three different element types have been developed and tested. The first is a solid tetra- hedral element with a linear stress distribution. The tri-axial stress state in the element is decomposed into concrete and reinforcement stresses, to which separate yield...... section forces such as plate bending and transverse shear. Examples are given which illustrates how the element can model plate and disk structures and the importance of taking transverse shear into account for structural problems with combined bending and transverse shear is illustrated....
Linking advanced fracture models to structural analysis
Energy Technology Data Exchange (ETDEWEB)
Chiesa, Matteo
2001-07-01
Shell structures with defects occur in many situations. The defects are usually introduced during the welding process necessary for joining different parts of the structure. Higher utilization of structural materials leads to a need for accurate numerical tools for reliable prediction of structural response. The direct discretization of the cracked shell structure with solid finite elements in order to perform an integrity assessment of the structure in question leads to large size problems, and makes such analysis infeasible in structural application. In this study a link between local material models and structural analysis is outlined. An ''ad hoc'' element formulation is used in order to connect complex material models to the finite element framework used for structural analysis. An improved elasto-plastic line spring finite element formulation, used in order to take cracks into account, is linked to shell elements which are further linked to beam elements. In this way one obtain a global model of the shell structure that also accounts for local flexibilities and fractures due to defects. An important advantage with such an approach is a direct fracture mechanics assessment e.g. via computed J-integral or CTOD. A recent development in this approach is the notion of two-parameter fracture assessment. This means that the crack tip stress tri-axiality (constraint) is employed in determining the corresponding fracture toughness, giving a much more realistic capacity of cracked structures. The present thesis is organized in six research articles and an introductory chapter that reviews important background literature related to this work. Paper I and II address the performance of shell and line spring finite elements as a cost effective tool for performing the numerical calculation needed to perform a fracture assessment. In Paper II a failure assessment, based on the testing of a constraint-corrected fracture mechanics specimen under tension, is
Non Linear Seismic Analysis of Masonry Structures
Directory of Open Access Journals (Sweden)
Sirajuddin, M
2011-12-01
Full Text Available Nowadays, even though many new construction techniques have been introduced, masonry has got its own importance in building industry. Masonry structures fail miserably under lateral loading conditions like earth quakes and impact loads. The occurrence of recent earthquakes in India and in different parts of the world have highlighted that most of the loss of human lives and damage to property have been due to the collapse of masonry structures. Though an earthquake could not be prevented, the loss of life and property could be minimized, if necessary steps could be taken to reduce the damages on the existing masonry structures. This paper investigates the application ofNonlinear Seismic Analysis of a masonry building using ANSYS software and check the efficacy of retrofit measuresto protect the existing building.
Entity Authentication:Analysis using Structured Intuition
DEFF Research Database (Denmark)
Ahmed, Naveed; Jensen, Christian D.
2010-01-01
for the protocol. All along this process, we discover vulnerabilities and unstated assumptions of the protocol. As the method is intuition based, the quality of results depends on the expertise of the security analyst, however, the structured intuition has two major advantages: Firstly we get a precise...... specification of security in terms of FLAGs; and secondly the outcome can be used to transform basic protocol narrations into more detailed specifications, which makes a subsequent formal analysis much more meaningful....
Structural analysis at aircraft conceptual design stage
Mansouri, Reza
In the past 50 years, computers have helped by augmenting human efforts with tremendous pace. The aircraft industry is not an exception. Aircraft industry is more than ever dependent on computing because of a high level of complexity and the increasing need for excellence to survive a highly competitive marketplace. Designers choose computers to perform almost every analysis task. But while doing so, existing effective, accurate and easy to use classical analytical methods are often forgotten, which can be very useful especially in the early phases of the aircraft design where concept generation and evaluation demands physical visibility of design parameters to make decisions [39, 2004]. Structural analysis methods have been used by human beings since the very early civilization. Centuries before computers were invented; the pyramids were designed and constructed by Egyptians around 2000 B.C, the Parthenon was built by the Greeks, around 240 B.C, Dujiangyan was built by the Chinese. Persepolis, Hagia Sophia, Taj Mahal, Eiffel tower are only few more examples of historical buildings, bridges and monuments that were constructed before we had any advancement made in computer aided engineering. Aircraft industry is no exception either. In the first half of the 20th century, engineers used classical method and designed civil transport aircraft such as Ford Tri Motor (1926), Lockheed Vega (1927), Lockheed 9 Orion (1931), Douglas DC-3 (1935), Douglas DC-4/C-54 Skymaster (1938), Boeing 307 (1938) and Boeing 314 Clipper (1939) and managed to become airborne without difficulty. Evidencing, while advanced numerical methods such as the finite element analysis is one of the most effective structural analysis methods; classical structural analysis methods can also be as useful especially during the early phase of a fixed wing aircraft design where major decisions are made and concept generation and evaluation demands physical visibility of design parameters to make decisions
Industrial entrepreneurial network: Structural and functional analysis
Medvedeva, M. A.; Davletbaev, R. H.; Berg, D. B.; Nazarova, J. J.; Parusheva, S. S.
2016-12-01
Structure and functioning of two model industrial entrepreneurial networks are investigated in the present paper. One of these networks is forming when implementing an integrated project and consists of eight agents, which interact with each other and external environment. The other one is obtained from the municipal economy and is based on the set of the 12 real business entities. Analysis of the networks is carried out on the basis of the matrix of mutual payments aggregated over the certain time period. The matrix is created by the methods of experimental economics. Social Network Analysis (SNA) methods and instruments were used in the present research. The set of basic structural characteristics was investigated: set of quantitative parameters such as density, diameter, clustering coefficient, different kinds of centrality, and etc. They were compared with the random Bernoulli graphs of the corresponding size and density. Discovered variations of random and entrepreneurial networks structure are explained by the peculiarities of agents functioning in production network. Separately, were identified the closed exchange circuits (cyclically closed contours of graph) forming an autopoietic (self-replicating) network pattern. The purpose of the functional analysis was to identify the contribution of the autopoietic network pattern in its gross product. It was found that the magnitude of this contribution is more than 20%. Such value allows using of the complementary currency in order to stimulate economic activity of network agents.
Energy Technology Data Exchange (ETDEWEB)
Sauerzopf, Clemens, E-mail: clemens.sauerzopf@oeaw.ac.at [Stefan Meyer Institute for subatomic Physics, Austrian Academy of Sciences, Boltzmanngasse 3, 1090 Wien (Austria); Capon, Aaron A.; Diermaier, Martin; Fleck, Markus; Kolbinger, Bernadette [Stefan Meyer Institute for subatomic Physics, Austrian Academy of Sciences, Boltzmanngasse 3, 1090 Wien (Austria); Malbrunot, Chloé [Stefan Meyer Institute for subatomic Physics, Austrian Academy of Sciences, Boltzmanngasse 3, 1090 Wien (Austria); Organisation Européenne pour la Recherche Nucléaire (CERN), 1211 Geneva 23 (Switzerland); Massiczek, Oswald; Simon, Martin C.; Vamosi, Stefan; Zmeskal, Johann; Widmann, Eberhard [Stefan Meyer Institute for subatomic Physics, Austrian Academy of Sciences, Boltzmanngasse 3, 1090 Wien (Austria)
2017-02-11
The matter-antimatter asymmetry observed in the universe today still lacks a quantitative explanation. One possible mechanism that could contribute to the observed imbalance is a violation of the combined Charge-, Parity- and Time symmetries (CPT). A test of CPT symmetry using anti-atoms is being carried out by the ASACUSA-CUSP collaboration at the CERN Antiproton Decelerator using a low temperature beam of antihydrogen—the most simple atomic system built only of antiparticles. While hydrogen is the most abundant element in the universe, antihydrogen is produced in very small quantities in a laboratory framework. A detector for in-beam measurements of the ground state hyperfine structure of antihydrogen has to be able to detect very low signal rates within high background. To fulfil this challenging task, a two layer barrel hodoscope detector was developed. It is built of plastic scintillators with double sided readout via Silicon Photomultipliers (SiPMs). The SiPM readout is done using novel, compact and cost efficient electronics that incorporate power supply, amplifier and discriminator on a single board. This contribution will evaluate the performance of the new hodoscope detector. - Highlights: • A novel detector for Antihydrogen was successfully commissioned. • A time of flight resolution of better than 1 ns was achieved. • Rudimentary 3D tracking is possible without bar segmentation.
Ogura, Hiroshi; Evans, John P; de Montellano, Paul R Ortiz; La Mar, Gerd N
2008-01-08
The triple mutant of the solubilized, 265-residue construct of human heme oxygenase, K18E/E29K/R183E-hHO, has been shown to redirect the exclusive alpha-regioselectivity of wild-type hHO to primarily beta,delta-selectivity in the cleavage of heme (Wang, J., Evans, J. P., Ogura, H., La Mar, G. N., and Ortiz de Montellano, P. R. (2006) Biochemistry 45, 61-73). The 1H NMR hyperfine shift pattern for the substrate and axial His CbetaH's and the substrate-protein contacts of the cyanide-inhibited protohemin and 2,4-dimethyldeuterohemin complexes of the triple mutant have been analyzed in detail and compared to data for the WT complex. It is shown that protein contacts for the major solution isomers for both substrates in the mutant dictate approximately 90 degrees in-plane clockwise rotation relative to that in the WT. The conventional interpretation of the pattern of substrate methyl hyperfine shifts, however, indicates substrate rotations of only approximately 50 degrees . This paradox is resolved by demonstrating that the axial His25 imidazole ring also rotates counterclockwise with respect to the protein matrix in the mutant relative to that in the WT. The axial His25 CbetaH hyperfine shifts are shown to serve as independent probes of the imidazole plane orientation relative to the protein matrix. The analysis indicates that the pattern of heme methyl hyperfine shifts cannot be used alone to determine the in-plane orientation of the substrate as it relates to the stereospecificity of heme cleavage, without explicit consideration of the orientation of the axial His imidazole plane relative to the protein matrix.
Finite Element Vibration and Dynamic Response Analysis of Engineering Structures
Directory of Open Access Journals (Sweden)
Jaroslav Mackerle
2000-01-01
Full Text Available This bibliography lists references to papers, conference proceedings, and theses/dissertations dealing with finite element vibration and dynamic response analysis of engineering structures that were published from 1994 to 1998. It contains 539 citations. The following types of structures are included: basic structural systems; ground structures; ocean and coastal structures; mobile structures; and containment structures.
Forward two-photon exchange in elastic lepton-proton scattering and hyperfine-splitting correction
Energy Technology Data Exchange (ETDEWEB)
Tomalak, Oleksandr [Johannes Gutenberg Universitaet, Institut fuer Kernphysik and PRISMA Cluster of Excellence, Mainz (Germany)
2017-08-15
We relate the forward two-photon exchange (TPE) amplitudes to integrals of the inclusive lepton-proton scattering cross sections. These relations yield an alternative way for the evaluation of the TPE correction to hyperfine-splitting (HFS) in the hydrogen-like atoms with an equivalent to the standard approach (Iddings, Drell and Sullivan) result implying the Burkhardt-Cottingham sum rule. For evaluation of the individual effects (e.g., elastic contribution) our approach yields a distinct result. We compare both methods numerically on examples of the elastic contribution and the full TPE correction to HFS in electronic and muonic hydrogen. (orig.)
Oshtrakh, M. I.; Novikov, E. G.; Dubiel, S. M.; Semionkin, V. A.
2010-04-01
Several commercially available medicaments containing ferrous fumarate (FeC4H2O4) and ferrous sulfate (FeSO4), as a source of ferrous iron, were studied using a high velocity resolution Mössbauer spectroscopy. A comparison of the 57Fe hyperfine parameters revealed small variations for the main components in both medicaments indicating some differences in the ferrous fumarates and ferrous sulfates. It was also found that all spectra contained additional minor components probably related to ferrous and ferric impurities or to partially modified main components.
Molecular Eigensolution Symmetry Analysis and Fine Structure
Directory of Open Access Journals (Sweden)
William G. Harter
2013-01-01
Full Text Available Spectra of high-symmetry molecules contain fine and superfine level cluster structure related to J-tunneling between hills and valleys on rovibronic energy surfaces (RES. Such graphic visualizations help disentangle multi-level dynamics, selection rules, and state mixing effects including widespread violation of nuclear spin symmetry species. A review of RES analysis compares it to that of potential energy surfaces (PES used in Born-Oppenheimer approximations. Both take advantage of adiabatic coupling in order to visualize Hamiltonian eigensolutions. RES of symmetric and D2 asymmetric top rank-2-tensor Hamiltonians are compared with Oh spherical top rank-4-tensor fine-structure clusters of 6-fold and 8-fold tunneling multiplets. Then extreme 12-fold and 24-fold multiplets are analyzed by RES plots of higher rank tensor Hamiltonians. Such extreme clustering is rare in fundamental bands but prevalent in hot bands, and analysis of its superfine structure requires more efficient labeling and a more powerful group theory. This is introduced using elementary examples involving two groups of order-6 (C6 and D3~C3v, then applied to families of Oh clusters in SF6 spectra and to extreme clusters.
Structural dynamic analysis of turbine blade
Antony, A. Daniel; Gopalsamy, M.; Viswanadh, Chaparala B. V.; Krishnaraj, R.
2017-10-01
In any gas turbine design cycle, blade design is a crucial element which needs maximum attention to meet the aerodynamic performance, structural safety margins, manufacturing feasibility, material availability etc. In present day gas turbine engines, most of the failures occur during engine development test and in-service, in rotor and stator blades due to fatigue and resonance failures. To address this issue, an extensive structural dynamic analysis is carried out to predict the natural frequencies and mode shapes using FE methods. Using the dynamics characteristics, the Campbell diagram is constructed to study the possibility of resonance at various operating speeds. In this work, the feasibility of using composite material in place of titanium alloy from the structural dynamics point of view. This is being attempted in a Low-pressure compressor where the temperatures are relatively low and fixed with the casings. The analysis will be carried out using FE method for different composite material with different lamina orientations chosen through the survey. This study will focus on the sensitivity of blade mode shapes to different laminae orientations, which will be used to alter the natural frequency and tailor the mode shapes. Campbell diagrams of existing titanium alloy are compared with the composite materials with different laminae at all critical operating conditions. The existing manufacturing methods and the proven techniques for blade profiles will also be discussed in this report.
The local structure of Co{sub 2}FeZ (Z=Si,Al,Ga,Ge) Heusler compounds probed by {sup 59}Co NMR
Energy Technology Data Exchange (ETDEWEB)
Wurmehl, Sabine; Kohlhepp, Juergen T.; Swagten, Henk J.M.; Koopmans, Bert [Eindhoven University of Technology, Eindhoven (Netherlands); Wojcik, Marek [Polish Academy of Sciences, Warszawa (Poland); Blum, Christian G.F.; Balke, Benjamin; Fecher, Gerhard H.; Ksenofontov, Vadim; Felser, Claudia [Johannes Gutenberg - Universitaet, Mainz (Germany)
2008-07-01
A thorough structural characterisation is one of the key tools in understanding the properties of spin polarised materials as the Heusler compounds Co{sub 2}FeZ with Z=(Si,Al,Ge,Ga). Spin echo nuclear magnetic resonance (NMR) spectroscopy provides a tool to probe the local structure by measuring the resonance frequencies and to probe the local hyperfine fields including the unique possibility to resolve the occupation and hyperfine fields of the neighboring shells. Thus, NMR was used to study the local (magnetic) structure of Co{sub 2}FeZ (Z=Al,Si,Ga,Ge) Heusler compounds, revealing different types of multiplet resonance lines for different types of Z atoms. The observed splitting of the resonance lines originates from different local environments of the {sup 59}Co nuclei. Analysis of the spectra yields the corresponding resonance frequencies and hyperfine magnetic fields as well as the spacing between consecutive resonance lines which leads to macroscopic structural models for the investigated Co{sub 2}FeZ Heusler compounds with Z=(Si,Al,Ge,Ga).
Nonlinear frequency response analysis of structural vibrations
Weeger, Oliver; Wever, Utz; Simeon, Bernd
2014-12-01
In this paper we present a method for nonlinear frequency response analysis of mechanical vibrations of 3-dimensional solid structures. For computing nonlinear frequency response to periodic excitations, we employ the well-established harmonic balance method. A fundamental aspect for allowing a large-scale application of the method is model order reduction of the discretized equation of motion. Therefore we propose the utilization of a modal projection method enhanced with modal derivatives, providing second-order information. For an efficient spatial discretization of continuum mechanics nonlinear partial differential equations, including large deformations and hyperelastic material laws, we employ the concept of isogeometric analysis. Isogeometric finite element methods have already been shown to possess advantages over classical finite element discretizations in terms of higher accuracy of numerical approximations in the fields of linear vibration and static large deformation analysis. With several computational examples, we demonstrate the applicability and accuracy of the modal derivative reduction method for nonlinear static computations and vibration analysis. Thus, the presented method opens a promising perspective on application of nonlinear frequency analysis to large-scale industrial problems.
Fiber structural analysis by synchrotron radiation
Kojima, J I; Kikutani, T
2003-01-01
Topics of fiber structural analysis by synchrotron radiation are explained. There are only three synchrotron radiation facilities in the world, SPring-8 (Super Photon ring-8) in Japan, APS (Advanced Photon Source) in U.S.A. and ESRF (European Synchrotron Radiation Facility) in France. Online measurement of melt spinning process of PET and Nylon6 is explained in detail. Polypropylene and PBO (poly-p-phenylenebenzobisoxazole) was measured by WAXD (Wide Angle X-ray Diffraction)/SAXS (Small Angle X-ray Scattering) at the same time. Some examples of measure of drawing process of fiber are described. The structure formation process of spider's thread was measured. Micro beam of X-ray of synchrotron facility was improved and it attained to 65nm small angle resolving power by 10 mu m beamsize. (S.Y.)
Energy Technology Data Exchange (ETDEWEB)
Lee, Young Shin; Choi, Myung Hwan; Kim, Young Wan; Oh, Jae Moon; Kim, Dong Jin; Song, Sun Young [Chungnam National University, Taejon (Korea, Republic of)
1996-07-01
In this study, the structural analysis of instrumented capsule and capsule supporting structures in HANARO in-core are performed. The structural= integrity of capsule structures are evaluated by the seismic analysis, thermal stresses and buckling stability analysis. The structural integrity of the capsule structure under impact loads are assessed and the mechanical characteristics of these structures through the stress analysis of joint bolts at the lower and of capsule mainbody and the strength analysis of the wire spring are analyzed. The design optimization of capsule structures are presented with considering mechanical characteristics. 20 refs., 12 tabs., 50 figs. (author)
Design and Analysis of the Membrane Structure
Directory of Open Access Journals (Sweden)
Ivan NĚMEC
2013-06-01
Full Text Available The article deals with problems in designing and analyzing the membrane structure of a stadium roof. Attention is especially given to problems relating to the optimal design of the shape of the membrane (form finding and the supporting cable system with respect to static behavior, functionality and architectural appearance. The work was carried out with respect to the companies Ing. Software Dlubal, s.r.o. and FEM consulting, s.r.o. intention to develop a new module of the RFEM program system capable of ascertaining the initial shape of a roof’s membrane construction and also its analysis for both static and dynamic wind loads.
Richert, Sabine; Cremers, Jonathan; Anderson, Harry L.
2016-01-01
Electron paramagnetic resonance (EPR) spectroscopy has been used to study the molecular geometry as well as metal–ligand interactions in ten-membered porphyrin nanorings (c-P10Cu2) containing two copper and eight zinc centers. The presence of copper in the structures allows intramolecular interactions, including dipolar interactions between electron spins and hyperfine interactions to be quantified. Results obtained for c-P10Cu2 samples bound to two molecular templates with four or five binding sites, respectively, are compared to those obtained for a sample of the porphyrin ring in the absence of any templates. It is shown that the observed lower binding affinity of the nitrogen ligand to copper as compared to zinc has a strong impact on the geometries of the respective template-bound c-P10Cu2 structures. The interaction between the central copper atom and nitrogen ligands is weak, but pulsed EPR hyperfine techniques such as ENDOR and HYSCORE are very sensitive to this interaction. Upon binding of a nitrogen ligand to copper, the hyperfine couplings of the in-plane nitrogen atoms of the porphyrin core are reduced by about 3 MHz. In addition, the copper hyperfine couplings as well as the g-factors are altered, as detected by continuous wave EPR. DFT calculations of the hyperfine coupling tensors support the assignment of the measured couplings to the nuclei within the structure and reproduce the experimentally observed trends. Finally, Double Electron Electron Resonance (DEER) is used to measure the distances between the copper centers in a range between 2.5 and 5 nm, revealing the preferred geometries of the template-bound nanorings. PMID:28451129
Hyperfine interactions and some thermomagnetic properties of amorphous FeZr(CrNbBCu alloys
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Łukiewska Agnieszka
2017-06-01
Full Text Available In this research, we studied the magnetic phase transition by Mössbauer spectroscopy and using vibrating sample magnetometer for amorphous Fe86-xZr7CrxNb2Cu1B4 (x = 0 or 6 alloys in the as-quenched state and after accumulative annealing in the temperature range 600-750 K. The Mössbauer investigations were carried out at room and nitrogen temperatures. The Mössbauer spectra of the investigated alloys at room temperature are characteristic of amorphous paramagnets and have a form of asymmetric doublets. However, at nitrogen temperature, the alloys behave like ferromagnetic amorphous materials. The two components are distinguished in the spectrum recorded at both room and nitrogen temperatures. The low field component in the distribution of hyperfine field induction shifts towards higher field with the annealing temperature. It is assumed that during annealing at higher temperature, due to diffusion processes, the grains of α-Fe are created in the area corresponding to this component. Both investigated alloys show the invar effect and the decrease of hyperfine field induction after annealing at 600 K for 10 min is observed. It is accompanied by the lowering of Curie temperature.
Precision measurement of the +25Mg ground-state hyperfine constant
Xu, Z. T.; Deng, K.; Che, H.; Yuan, W. H.; Zhang, J.; Lu, Z. H.
2017-11-01
We report an experimental determination of the ground-state hyperfine constant A of the +25Mg ions by measuring the | S1 /2,F =2 ,m =0 〉 to | S1 /2,F =3 ,m =0 〉 transition (0-0 transition) frequency of the two ground-state hyperfine energy levels. The frequency is measured by rf resonant method in a Paul trap under a magnetic field of about 0.1 mT. The result is A =-596.254 248 7(42) MHz. Different frequency shifts and uncertainties are evaluated. The main effect is quadratic Zeeman shift. Since the Paul trap is driven by rf on the electrodes, ac magnetic field can be induced by the rf at the site of the ion. The ac magnetic field causes quadratic Zeeman shift for ion frequency standards and also reduces the coherence time when the ion acts as a quantum bit. Precision measurement of this ac magnetic field can help evaluating the related uncertainty when a single-ion optical clock is established on the trap.
Hyperfine and Spin-Orbit Coupling Effects on Decay of Spin-Valley States in a Carbon Nanotube
Pei, T.; Pályi, A.; Mergenthaler, M.; Ares, N.; Mavalankar, A.; Warner, J. H.; Briggs, G. A. D.; Laird, E. A.
2017-04-01
The decay of spin-valley states is studied in a suspended carbon nanotube double quantum dot via the leakage current in Pauli blockade and via dephasing and decoherence of a qubit. From the magnetic field dependence of the leakage current, hyperfine and spin-orbit contributions to relaxation from blocked to unblocked states are identified and explained quantitatively by means of a simple model. The observed qubit dephasing rate is consistent with the hyperfine coupling strength extracted from this model and inconsistent with dephasing from charge noise. However, the qubit coherence time, although longer than previously achieved, is probably still limited by charge noise in the device.
Dorris, William J.; Hairr, John W.; Huang, Jui-Tien; Ingram, J. Edward; Shah, Bharat M.
1992-01-01
Non-linear analysis methods were adapted and incorporated in a finite element based DIAL code. These methods are necessary to evaluate the global response of a stiffened structure under combined in-plane and out-of-plane loading. These methods include the Arc Length method and target point analysis procedure. A new interface material model was implemented that can model elastic-plastic behavior of the bond adhesive. Direct application of this method is in skin/stiffener interface failure assessment. Addition of the AML (angle minus longitudinal or load) failure procedure and Hasin's failure criteria provides added capability in the failure predictions. Interactive Stiffened Panel Analysis modules were developed as interactive pre-and post-processors. Each module provides the means of performing self-initiated finite elements based analysis of primary structures such as a flat or curved stiffened panel; a corrugated flat sandwich panel; and a curved geodesic fuselage panel. This module brings finite element analysis into the design of composite structures without the requirement for the user to know much about the techniques and procedures needed to actually perform a finite element analysis from scratch. An interactive finite element code was developed to predict bolted joint strength considering material and geometrical non-linearity. The developed method conducts an ultimate strength failure analysis using a set of material degradation models.
Jointly Learning Structured Analysis Discriminative Dictionary and Analysis Multiclass Classifier.
Zhang, Zhao; Jiang, Weiming; Qin, Jie; Zhang, Li; Li, Fanzhang; Zhang, Min; Yan, Shuicheng
2017-09-14
In this paper, we propose an analysis mechanism-based structured analysis discriminative dictionary learning (ADDL) framework. The ADDL seamlessly integrates ADDL, analysis representation, and analysis classifier training into a unified model. The applied analysis mechanism can make sure that the learned dictionaries, representations, and linear classifiers over different classes are independent and discriminating as much as possible. The dictionary is obtained by minimizing a reconstruction error and an analytical incoherence promoting term that encourages the subdictionaries associated with different classes to be independent. To obtain the representation coefficients, ADDL imposes a sparse l2,1-norm constraint on the coding coefficients instead of using l₀ or l₁ norm, since the l₀- or l₁-norm constraint applied in most existing DL criteria makes the training phase time consuming. The code-extraction projection that bridges data with the sparse codes by extracting special features from the given samples is calculated via minimizing a sparse code approximation term. Then we compute a linear classifier based on the approximated sparse codes by an analysis mechanism to simultaneously consider the classification and representation powers. Thus, the classification approach of our model is very efficient, because it can avoid the extra time-consuming sparse reconstruction process with trained dictionary for each new test data as most existing DL algorithms. Simulations on real image databases demonstrate that our ADDL model can obtain superior performance over other state of the arts.
Structural and magnetic characterization of maghemites prepared from Al-substituted magnetites
Directory of Open Access Journals (Sweden)
Marcelo Augusto Batista
2013-12-01
Full Text Available Synthetic aluminum-substituted maghemites were characterized by total chemical analysis, powder X-ray diffraction (XRD, Mössbauer spectroscopy (ME, and vibrating sample magnetometry (VSM. The aim was to determine the structural, magnetic, and hyperfine properties of γ-Fe2-xAl xO3 as the Al concentration is varied. The XRD results of the synthetic products were indexed exclusively as maghemite. Increasing Al for Fe substitution decreased the mean crystalline dimension and shifted all diffraction peaks to higher º2θ angles. The a0 dimension of the cubic unit cell decreased with increasing Al according to the equation a o = 0.8385 - 3.63 x 10-5 Al (R²= 0.94. Most Mössbauer spectra were composed of one sextet, but at the highest substitution rate of 142.5 mmol mol-1 Al, both a doublet and sextet were obtained at 300 K. All hyperfine parameters from the sub-spectra were consistent with high-spin Fe3+ (0.2 a 0.7 mms-1 and suggested a strong superparamagnetic component associated with the doublet. The magnetic hyperfine field of the sextets decreased with the amount of Al-substitution [Bhf (T = 49.751 - 0.1202Al; R² = 0.94] while the linewidth increased linearly. The saturation magnetization also decreased with increasing isomorphous substitution.
Structural reliability analysis applied to pipeline risk analysis
Energy Technology Data Exchange (ETDEWEB)
Gardiner, M. [GL Industrial Services, Loughborough (United Kingdom); Mendes, Renato F.; Donato, Guilherme V.P. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)
2009-07-01
Quantitative Risk Assessment (QRA) of pipelines requires two main components to be provided. These are models of the consequences that follow from some loss of containment incident, and models for the likelihood of such incidents occurring. This paper describes how PETROBRAS have used Structural Reliability Analysis for the second of these, to provide pipeline- and location-specific predictions of failure frequency for a number of pipeline assets. This paper presents an approach to estimating failure rates for liquid and gas pipelines, using Structural Reliability Analysis (SRA) to analyze the credible basic mechanisms of failure such as corrosion and mechanical damage. SRA is a probabilistic limit state method: for a given failure mechanism it quantifies the uncertainty in parameters to mathematical models of the load-resistance state of a structure and then evaluates the probability of load exceeding resistance. SRA can be used to benefit the pipeline risk management process by optimizing in-line inspection schedules, and as part of the design process for new construction in pipeline rights of way that already contain multiple lines. A case study is presented to show how the SRA approach has recently been used on PETROBRAS pipelines and the benefits obtained from it. (author)
Comparative analysis of steel structures stationary conveyors with hanging belt
Directory of Open Access Journals (Sweden)
Boslovyak P.V.
2016-06-01
Full Text Available Presents the results of computation of metal structures LLC «Сonveyor» with the subsequent analysis of its main struc-tural units. The analysis results of the metal structures, LLC «Сonveyor» with a similar metal structure obtained in the optimal design process.
Free vibration analysis of spinning structural systems.
Gupta, K. K.
1973-01-01
This article presents an efficient digital computer procedure, along with the complete listing of the associated computer program, which may be conveniently utilized for the accurate solution of a wide range of practical eigenvalue problems. Important applications of the present work are envisaged in the natural frequency analysis of spinning structures discretized by the finite element technique, and in the determination of transfer functions associated with the dynamic blocks of control systems of spacecraft utilizing gas jets or reaction wheels for attitude control, as well as of spin-stabilized and dual-spin-stabilized satellites. The validity of the Sturm sequence property is first established for the related matrix formulation involving Hermitian and real symmetric, positive-definite matrices, both being usually of highly banded configuration. A numerically stable algorithm based on the Sturm sequence method is then developed which fully exploits the banded form of the associated matrices.
Inelastic analysis of solids and structures
Kojic, M; Bathe, K J; Koji?, Milo
2005-01-01
Inelastic Analysis of Solids and Structures presents in a unified manner the physical and theoretical background of inelastic material models and computational methods, and illustrates the behavior of the models in typical engineering conditions.It is based on experimental observations and principles of mechanics, thus describing computational algorithms for stress calculation and presenting solved examples.The theoretical background is given to an extent necessary to describe the commonly employed material models in metal isotropic and orthotropic plasticity, thermoplasticity and viscoplasticity, and the plasticity of geological materials.The computational algorithms are developed in a unified manner with some detailed derivations of the algorithmic relations.The solved examples are designed to give insight into the material behavior in various engineering conditions, and to demonstrate the application of the computational algorithms.
Hyperfine interactions in nanocrystallized NANOPERM-type metallic glass containing Mo
Energy Technology Data Exchange (ETDEWEB)
Cesnek, M., E-mail: martin.cesnek@fjfi.cvut.cz [Czech Technical University in Prague, Department of Nuclear Reactors, Faculty of Nuclear Science and Physical Engineering (Czech Republic); Kubániová, D.; Kohout, J.; Křišťan, P.; Štěpánková, H.; Závěta, K. [Charles University, Department of Low Temperature Physics, Faculty of Mathematics and Physics (Czech Republic); Lančok, A. [Institute of Inorganic Chemistry AS CR (Czech Republic); Štefánik, M.; Miglierini, M. [Czech Technical University in Prague, Department of Nuclear Reactors, Faculty of Nuclear Science and Physical Engineering (Czech Republic)
2016-12-15
NANOPERM-type alloy with chemical composition Fe{sub 76}Mo{sub 8}CuB{sub 15} was studied by combination of {sup 57}Fe Mössbauer spectroscopy and {sup 57}Fe({sup 10}B, {sup 11}B) nuclear magnetic resonance in order to determine distribution of hyperfine magnetic fields and evolution of relative concentration of Fe-containing crystalline phases within the surface layer and the volume of the nanocrystallized ribbons with annealing temperature. Differential scanning calorimetry revealed two crystallization stages at T{sub x1} ∼ 510 {sup ∘}C and T{sub x2} ∼ 640 {sup ∘}C, connected to precipitation of α-Fe and Fe(Mo,B) nanocrystals, respectively. The amorphous and partially crystalline state was obtained by annealing at several temperatures in the range 510-650 {sup ∘}C. The combination of conversion electron (CEMS) and transmission Mössbauer spectrometry (TMS) showed that annealing induces crystallization starting from both surfaces of the ribbons. For the as-quenched sample, scanning electron microscopy (SEM) and CEMS revealed significant differences in the “air” and “wheel” sides of the ribbons, crystallites were preferentially formed at the latter. While SEM micrographs of annealed samples showed various mean diameters of the crystals at opposite sides of the ribbons, the amounts of crystalline volume derived from the CEMS spectra approximately equaled. Mössbauer spectra of annealed samples contained narrow sextet ascribed to crystalline α-Fe phase, three sextets with distribution of hyperfine field assigned to the interface regions of the nanocrystals and the contribution of the amorphous phases. In-field TMS performed at 4.2 K with magnetic moments aligned by external magnetic field enabled to properly determine in particular the contribution of the amorphous phases in the samples. Resulting distributions of the hyperfine fields were compared with {sup 57}Fe({sup 10}B, {sup 11}B) nuclear magnetic resonance (NMR) spectra.
Cox, Nicholas; Ames, William; Epel, Boris; Kulik, Leonid V; Rapatskiy, Leonid; Neese, Frank; Messinger, Johannes; Wieghardt, Karl; Lubitz, Wolfgang
2011-09-05
An analysis of the electronic structure of the [Mn(II)Mn(III)(μ-OH)-(μ-piv)(2)(Me(3)tacn)(2)](ClO(4))(2) (PivOH) complex is reported. It displays features that include: (i) a ground 1/2 spin state; (ii) a small exchange (J) coupling between the two Mn ions; (iii) a mono-μ-hydroxo bridge, bis-μ-carboxylato motif; and (iv) a strongly coupled, terminally bound N ligand to the Mn(III). All of these features are observed in structural models of the oxygen evolving complex (OEC). Multifrequency electron paramagnetic resonance (EPR) and electron nuclear double resonance (ENDOR) measurements were performed on this complex, and the resultant spectra simulated using the Spin Hamiltonian formalism. The strong field dependence of the (55)Mn-ENDOR constrains the (55)Mn hyperfine tensors such that a unique solution for the electronic structure can be deduced. Large hyperfine anisotropy is required to reproduce the EPR/ENDOR spectra for both the Mn(II) and Mn(III) ions. The large effective hyperfine tensor anisotropy of the Mn(II), a d(5) ion which usually exhibits small anisotropy, is interpreted within a formalism in which the fine structure tensor of the Mn(III) ion strongly perturbs the zero-field energy levels of the Mn(II)Mn(III) complex. An estimate of the fine structure parameter (d) for the Mn(III) of -4 cm(-1) was made, by assuming the intrinsic anisotropy of the Mn(II) ion is small. The magnitude of the fine structure and intrinsic (onsite) hyperfine tensor of the Mn(III) is consistent with the known coordination environment of the Mn(III) ion as seen from its crystal structure. Broken symmetry density functional theory (DFT) calculations were performed on the crystal structure geometry. DFT values for both the isotropic and the anisotropic components of the onsite (intrinsic) hyperfine tensors match those inferred from the EPR/ENDOR simulations described above, to within 5%. This study demonstrates that DFT calculations provide reliable estimates for spectroscopic
Chemical structural analysis of diamondlike carbon films: II. Raman analysis
Takabayashi, Susumu; Ješko, Radek; Shinohara, Masanori; Hayashi, Hiroyuki; Sugimoto, Rintaro; Ogawa, Shuichi; Takakuwa, Yuji
2018-02-01
The chemical structure of diamondlike carbon (DLC) films, synthesized by photoemission-assisted glow discharge, has been analyzed by Raman spectroscopy. Raman analysis in conjunction with the sp2 cluster model clarified the film structure. The sp2 clusters in DLC films synthesized at low temperature preferred various aliphatic structures. Sufficient argon-ion assist allowed for formation of less strained DLC films containing large amounts of hydrogen. As the synthesis temperature was increased, thermal desorption of hydrogen left carbon dangling bonds with active unpaired electrons in the films, and the reactions that followed created strained films containing aromatic sp2 clusters. In parallel, the desorption of methane molecules from the growing surface by chemisorption of hydrogen radicals prevented the action of argon ions, promoting internal strain of the films. However, in synthesis at very high temperature, where sp2 clusters are sufficiently dominant, the strain was dissolved gradually. In contrast, the DLC films synthesized at low temperature were more stable than other films synthesized at the same temperature because of stable hydrogen-carbon bonds in the films.
Rapatskiy, Leonid; Ames, William M; Pérez-Navarro, Montserrat; Savitsky, Anton; Griese, Julia J; Weyhermüller, Thomas; Shafaat, Hannah S; Högbom, Martin; Neese, Frank; Pantazis, Dimitrios A; Cox, Nicholas
2015-10-29
Multifrequency pulsed EPR data are reported for a series of oxygen bridged (μ-oxo/μ-hydroxo) bimetallic manganese complexes where the oxygen is labeled with the magnetically active isotope (17)O (I = 5/2). Two synthetic complexes and two biological metallocofactors are examined: a planar bis-μ-oxo bridged complex and a bent, bis-μ-oxo-μ-carboxylato bridge complex; the dimanganese catalase, which catalyzes the dismutation of H2O2 to H2O and O2, and the recently identified manganese/iron cofactor of the R2lox protein, a homologue of the small subunit of the ribonuclotide reductase enzyme (class 1c). High field (W-band) hyperfine EPR spectroscopies are demonstrated to be ideal methods to characterize the (17)O magnetic interactions, allowing a magnetic fingerprint for the bridging oxygen ligand to be developed. It is shown that the μ-oxo bridge motif displays a small positive isotropic hyperfine coupling constant of about +5 to +7 MHz and an anisotropic/dipolar coupling of -9 MHz. In addition, protonation of the bridge is correlated with an increase of the hyperfine coupling constant. Broken symmetry density functional theory is evaluated as a predictive tool for estimating hyperfine coupling of bridging species. Experimental and theoretical results provide a framework for the characterization of the oxygen bridge in Mn metallocofactor systems, including the water oxidizing cofactor of photosystem II, allowing the substrate/solvent interface to be examined throughout its catalytic cycle.
Energy Technology Data Exchange (ETDEWEB)
Baker, M. [Alberta Univ., Edmonton, AB (Canada). Dept. of Physics; Marquard, P. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Penin, A.A. [Alberta Univ., Edmonton, AB (Canada). Dept. of Physics; Karlsruher Institut fuer Technologie (Germany). Inst. fuer Theoretische Teilchenphysik; Piclum, J. [Technische Univ. Muenchen, Garching (Germany). Physik-Department; RWTH Aachen (Germany). Inst. fuer Theoretische Teilchenphysik und Kosmologie; Steinhauser, M. [Karlsruher Institut fuer Technologie (Germany). Inst. fuer Theoretische Teilchenphysik
2014-02-15
We present the complete result for the O({alpha}{sup 7}m{sub e}) one-photon annihilation contribution to the hyperfine splitting of the ground state energy levels in positronium. Numerically it increases the prediction of quantum electrodynamics by 217{+-}1 kHz.
Harter, William; Mitchell, Justin
2009-06-01
At several points in his defining works on molecular spectroscopy, Herzberg notes that ``because nuclear moments ldots are so very slight ldots transitions between species ldots are very strictly forbiddenldots '' Herzberg's most recent statement of such selection rules pertained to spherical top spin-species. It has since been shown that spherical top species (as well as those of lower symmetry molecules) converge exponentially with momentum quanta J and K to degenerate level clusters wherein even ``very slight'' nuclear fields and moments cause pervasive resonance and total spin species mixing. Ultra-high resolution spectra of Borde, et .al and Pfister et .al shows how SF_6 and SiF_4 Fluorine nuclear spin levels rearrange from total-spin multiplets to NMR-like patterns as their superfine structure converges. Similar super-hyperfine effects are anticipated for lower symmetry molecules exhibiting converging superfine level-clusters. Examples include PH_3 molecules and asymmetric tops. Following this we consider models that treat nuclear spins as coupled rotors undergoing generalized Hund-case transitions from spin-lab-momentum coupling to various spin-rotor correlations. G. A. Herzberg, Electronic Spectra of Polyatomic Molecules, (Von Norstrand Rheinhold 1966) p. 246. W G. Harter and C. W Patterson, Phys. Rev. A 19, 2277 (1979) W. G. Harter, Phys. Rev. A 24, 192 (1981). Ch. J. Borde, J. Borde, Ch. Breant, Ch. Chardonnet, A. Van Lerberghe, and Ch. Salomon, in Laser Spectroscopy VII, T. W Hensch and Y. R. Shen, eds. (Springer-Verlag, Berlin, 1985). O. Pfister, F. Guernet, G. Charton, Ch. Chardonnet, F. Herlemont, and J. Legrand, J. Opt. Soc. Am. B 10, 1521 (1993). O. Pfister, Ch. Chardonnet, and Ch. J. Bordè, Phys. Rev. Lett. 76, 4516 (1996) S. N. Yurchenko, W. Thiel, S. Patchkovskii, and P. Jensen, Phys. Chem. Chem. Phys.7, 573 (2005)
Toward the measurement of the hyperfine splitting in the ground state of muonic hydrogen
Energy Technology Data Exchange (ETDEWEB)
Bakalov, Dimitar, E-mail: dbakalov@inrne.bas.bg [Bulgarian Academy of Sciences, Institute for Nuclear Research and Nuclear Energy (Bulgaria); Adamczak, Andrzej [Polish Academy of Sciences, Institute of Nuclear Physics (Poland); Stoilov, Mihail [Bulgarian Academy of Sciences, Institute for Nuclear Research and Nuclear Energy (Bulgaria); Vacchi, Andrea [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste (Italy)
2015-08-15
The recent Lamb shift experiment at PSI and the controversy about proton size revived the interest in measuring the hyperfine splitting in muonic hydrogen and extracting the proton Zemach radius. The efficiency of the experimental method depends on the energy dependence of the muon transfer rate to higher-Z gases in the near epithermal energy range. As long as the available experimental data only give the average transfer rate in the whole epithermal range, and the detailed theoretical calculations have not yet been verified, an experiment has been started for the measurement of the transfer rate in thermalized gas target at different temperatures and extracting from the data an estimate of the transfer rate for arbitrary energies. We outline the underlying mathematical method and estimate its accuracy.
Protein Structure Recognition: From Eigenvector Analysis to Structural Threading Method
Energy Technology Data Exchange (ETDEWEB)
Cao, Haibo [Iowa State Univ., Ames, IA (United States)
2003-01-01
In this work, they try to understand the protein folding problem using pair-wise hydrophobic interaction as the dominant interaction for the protein folding process. They found a strong correlation between amino acid sequences and the corresponding native structure of the protein. Some applications of this correlation were discussed in this dissertation include the domain partition and a new structural threading method as well as the performance of this method in the CASP5 competition. In the first part, they give a brief introduction to the protein folding problem. Some essential knowledge and progress from other research groups was discussed. This part includes discussions of interactions among amino acids residues, lattice HP model, and the design ability principle. In the second part, they try to establish the correlation between amino acid sequence and the corresponding native structure of the protein. This correlation was observed in the eigenvector study of protein contact matrix. They believe the correlation is universal, thus it can be used in automatic partition of protein structures into folding domains. In the third part, they discuss a threading method based on the correlation between amino acid sequences and ominant eigenvector of the structure contact-matrix. A mathematically straightforward iteration scheme provides a self-consistent optimum global sequence-structure alignment. The computational efficiency of this method makes it possible to search whole protein structure databases for structural homology without relying on sequence similarity. The sensitivity and specificity of this method is discussed, along with a case of blind test prediction. In the appendix, they list the overall performance of this threading method in CASP5 blind test in comparison with other existing approaches.
Hyperfine structure investigations of Pr-I lines in the region 4200-4450 A
Energy Technology Data Exchange (ETDEWEB)
Siddiqui, Imran; Khan, Shamim; Tanweer Iqbal, Syed; Windholz, Laurentius [Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, A 8010 Graz (Austria)
2012-07-01
Praseodymium I spectral lines were investigated using laser induced fluorescence spectroscopy in a hollow cathode discharge lamp. The investigations led to the discovery of new Pr I energy levels of even and odd parity. A high resolution Fourier transform (FT) spectrum was used to extract promising excitation wavelengths. In the FT spectrum the investigated line 4375.53 A shows up as a narrow peak hfs with a weak SNR. Nevertheless, the line was excited and fluorescence signals were observed on 6 lines (4163 A, 4816 A, 5091 A, 5164 A, 5209 A, 5233 A). The hfs of the line was recorded by scanning the laser frequency and was fitted to obtain angular momentum J and hf constant A of the combining levels. We got J{sub up}=5/2, A{sub up}=1028.30 MHz, J{sub lo}=7/2 and A{sub lo}=861.46 MHz (the subscripts refer to upper and lower level). Assuming an unknown upper level, a known lower level was searched among the known levels having sufficient values of J and A. The level 7617.440 cm{sup -1}, even parity, J{sub lo}=7/2 and A{sub lo}=868 MHz fulfils these requirements. Using the center of gravity wave number of the line 4375.53 A and the energy of the lower level, the unknown upper level was calculated to have 30465.424 cm{sup -1}, odd parity, J{sub up}=5/2 and A{sub up}=1033(6) MHz.
Structural analysis of galactoarabinan from duckweed.
Yu, Li; Yu, Changjiang; Zhu, Ming; Cao, Yingping; Yang, Haiyan; Zhang, Xu; Ma, Yubin; Zhou, Gongke
2015-03-06
A highly branched galactoarabinan named DAG1 (Mw∼4.0×10(4) Da) was purified from Lemna aequinoctialis 6000 via 70% (v/v) ethanol extraction, followed by size-exclusion chromatography on Bio-Gel P2 and Superdex 75. Methylation analysis showed that DAG1 consisted of t-Araf, (1→5)-Araf, (1→2,5)-Araf, (1→3)-Galp, and (1→3,6)-Galp in a relative proportion of approximately 6:4:3:3:3, suggesting an arabinogalactan/galactoarabinan polysacchairde. With the aid of arabinan degrading enzymes, the structure of DAG1 repeating unit was further characterized by ELISA with specific monoclonal antibodies and Yariv reagent assay. Analyses indicated that the proposed repeating unit of DAG1 had a backbone composed of seven α-(1→5)-L-arabinofuranose residues where branching occurred at O-2 with either terminal arabinoses or arabinogalactan side chain. The arabinogalactan side chain was composed of six β-(1→3)-D-galactopyranose residues, half of which were ramified at O-6 with terminal arabinoses and the last galactose was terminated with arabinose. Copyright © 2014 Elsevier Ltd. All rights reserved.
Structural Analysis of the Ignitor Load Assembly
Bianchi, A.; Cucchiaro, A.; Coppi, B.
2005-10-01
The structural analysis of all components of the Ignitor machine, and of their mechanical interactions, has been performed by using the Finite Element Method and ANSYS program for the most advanced plasma scenarios. Friction coefficients have been taken into account at the interfaces between relevant components. The results show that the stresses produced are within the allowable limits at the considered temperatures of the magnet. The out-of-plane loads were carefully evaluated by means of a dedicated code developed in ENEA, both for the reference operating scenario and for the worst plasma disruption. The disruption scenario chosen as representive of the most dangerous plasma conditions in Ignitor is a Vertical Displacement Event followed by a fast thermal and current quench, simulated by the MAXFEA code. The resulting loads were also confirmed by the ANSYS code. The average shear stress at the toroidal field coil interfaces due to these out-of-plane loads is lower than the friction coefficient and do not increase significantly the in-plane maximum equivalent stresses.
Free-Vibration Analysis of Structures
Gupta, K. K.
1985-01-01
Improved numerical procedure more than twice as fast as previous methods. Unified numerical algorithm efficiently solves free-vibration problems of stationary or spinning structures with or without viscous or structural damping. Algorithm used to solve static problems involving multiple loads and to solve quadratic matrix eigenvalue problems associated with finite-dynamic-element structural discretization.
Analysis of latent structures in linear systems
DEFF Research Database (Denmark)
Høskuldsson, Agnar
2004-01-01
In chemometrics the emphasis is on latent structure models. The latent structure is the part of the data that the modeling task is based upon. This paper is addressing some fundamental issues, when latent structures are used. The paper consists of three parts. The first part is concerned defining...... that are useful, when studying latent structures. It is shown how loading weight vectors are generated and how they can be interpreted in analyzing the latent structure. It is shown how the covariance can be used to get useful ‘apriori’ information on the modeling task. Also some simple methods are presented...
BioMatriX: Sequence analysis, structure visualization, phylogenetics ...
African Journals Online (AJOL)
Goshi
2012-04-26
Apr 26, 2012 ... multi-functional services to perform specific tasks like DNA/RNA/Protein sequence analysis with graphical representations, sequence editing, sequence alignment, restriction enzyme mapping, protein structure visualization, mutation and structure superimposition programs along with phylogenetics tree.
Analysis and design technology for high-speed aircraft structures
Starnes, James H., Jr.; Camarda, Charles J.
1992-01-01
Recent high-speed aircraft structures research activities at NASA Langley Research Center are described. The following topics are covered: the development of analytical and numerical solutions to global and local thermal and structural problems, experimental verification of analysis methods, identification of failure mechanisms, and the incorporation of analysis methods into design and optimization strategies. The paper describes recent NASA Langley advances in analysis and design methods, structural and thermal concepts, and test methods.
Value of Information Analysis in Structural Safety
DEFF Research Database (Denmark)
Konakli, Katerina; Faber, Michael Havbro
2014-01-01
of structural systems. In this context, experiments may refer to inspections or techniques of structural health monitoring. The Value of Information concept provides a powerful tool for determining whether the experimental cost is justified by the expected benefit and for identifying the optimal among different...
Synthesis, structure and Hirshfeld surface analysis, vibrational and ...
Indian Academy of Sciences (India)
-dimensional architecture. Hirshfeld surface analysis for visually analysing intermolecular interactions in crystal structures employing molecular surfacecontours and 2D fingerprint plots has been used to scrutinize molecular shapes.
Codeword Structure Analysis for LDPC Convolutional Codes
Directory of Open Access Journals (Sweden)
Hua Zhou
2015-12-01
Full Text Available The codewords of a low-density parity-check (LDPC convolutional code (LDPC-CC are characterised into structured and non-structured. The number of the structured codewords is dominated by the size of the polynomial syndrome former matrix H T ( D , while the number of the non-structured ones depends on the particular monomials or polynomials in H T ( D . By evaluating the relationship of the codewords between the mother code and its super codes, the low weight non-structured codewords in the super codes can be eliminated by appropriately choosing the monomials or polynomials in H T ( D , resulting in improved distance spectrum of the mother code.
MC^{2}-3: Multigroup Cross Section Generation Code for Fast Reactor Analysis
Energy Technology Data Exchange (ETDEWEB)
Lee, C. H. [Argonne National Lab. (ANL), Argonne, IL (United States); Yang, W. S. [Argonne National Lab. (ANL), Argonne, IL (United States)
2013-11-08
The MC^{2}-3 code is a Multigroup Cross section generation Code for fast reactor analysis, developed by improving the resonance self-shielding and spectrum calculation methods of MC^{2}-2 and integrating the one-dimensional cell calculation capabilities of SDX. The code solves the consistent P1 multigroup transport equation using basic neutron data from ENDF/B data files to determine the fundamental mode spectra for use in generating multigroup neutron cross sections. A homogeneous medium or a heterogeneous slab or cylindrical unit cell problem is solved in ultrafine (~2000) or hyperfine (~400,000) group levels. In the resolved resonance range, pointwise cross sections are reconstructed with Doppler broadening at specified isotopic temperatures. The pointwise cross sections are directly used in the hyperfine group calculation whereas for the ultrafine group calculation, self-shielded cross sections are prepared by numerical integration of the pointwise cross sections based upon the narrow resonance approximation. For both the hyperfine and ultrafine group calculations, unresolved resonances are self-shielded using the analytic resonance integral method. The ultrafine group calculation can also be performed for two-dimensional whole-core problems to generate region-dependent broad-group cross sections. Multigroup cross sections are written in the ISOTXS format for a user-specified group structure. The code is executable on UNIX, Linux, and PC Windows systems, and its library includes all isotopes of the ENDF/BVII. 0 data.
Reliability analysis applied to structural tests
Diamond, P.; Payne, A. O.
1972-01-01
The application of reliability theory to predict, from structural fatigue test data, the risk of failure of a structure under service conditions because its load-carrying capability is progressively reduced by the extension of a fatigue crack, is considered. The procedure is applicable to both safe-life and fail-safe structures and, for a prescribed safety level, it will enable an inspection procedure to be planned or, if inspection is not feasible, it will evaluate the life to replacement. The theory has been further developed to cope with the case of structures with initial cracks, such as can occur in modern high-strength materials which are susceptible to the formation of small flaws during the production process. The method has been applied to a structure of high-strength steel and the results are compared with those obtained by the current life estimation procedures. This has shown that the conventional methods can be unconservative in certain cases, depending on the characteristics of the structure and the design operating conditions. The suitability of the probabilistic approach to the interpretation of the results from full-scale fatigue testing of aircraft structures is discussed and the assumptions involved are examined.
Optimal analysis of structures by concepts of symmetry and regularity
Kaveh, Ali
2013-01-01
Optimal analysis is defined as an analysis that creates and uses sparse, well-structured and well-conditioned matrices. The focus is on efficient methods for eigensolution of matrices involved in static, dynamic and stability analyses of symmetric and regular structures, or those general structures containing such components. Powerful tools are also developed for configuration processing, which is an important issue in the analysis and design of space structures and finite element models. Different mathematical concepts are combined to make the optimal analysis of structures feasible. Canonical forms from matrix algebra, product graphs from graph theory and symmetry groups from group theory are some of the concepts involved in the variety of efficient methods and algorithms presented. The algorithms elucidated in this book enable analysts to handle large-scale structural systems by lowering their computational cost, thus fulfilling the requirement for faster analysis and design of future complex systems. The ...
Field distribution analysis in deflecting structures
Energy Technology Data Exchange (ETDEWEB)
Paramonov, V.V. [Joint Inst. for Nuclear Research, Moscow (Russian Federation)
2013-02-15
Deflecting structures are used now manly for bunch rotation in emittance exchange concepts, bunch diagnostics and to increase the luminosity. The bunch rotation is a transformation of a particles distribution in the six dimensional phase space. Together with the expected transformations, deflecting structures introduce distortions due to particularities - aberrations - in the deflecting field distribution. The distributions of deflecting fields are considered with respect to non linear additions, which provide emittance deteriorations during a transformation. The deflecting field is treated as combination of hybrid waves HE{sub 1} and HM{sub 1}. The criteria for selection and formation of deflecting structures with minimized level of aberrations are formulated and applied to known structures. Results of the study are confirmed by comparison with results of numerical simulations.
Structural analysis of kasugamycin inhibition of translation.
Schuwirth, Barbara S; Day, J Michael; Hau, Cathy W; Janssen, Gary R; Dahlberg, Albert E; Cate, Jamie H Doudna; Vila-Sanjurjo, Antón
2006-10-01
The prokaryotic ribosome is an important target of antibiotic action. We determined the X-ray structure of the aminoglycoside kasugamycin (Ksg) in complex with the Escherichia coli 70S ribosome at 3.5-A resolution. The structure reveals that the drug binds within the messenger RNA channel of the 30S subunit between the universally conserved G926 and A794 nucleotides in 16S ribosomal RNA, which are sites of Ksg resistance. To our surprise, Ksg resistance mutations do not inhibit binding of the drug to the ribosome. The present structural and biochemical results indicate that inhibition by Ksg and Ksg resistance are closely linked to the structure of the mRNA at the junction of the peptidyl-tRNA and exit-tRNA sites (P and E sites).
LACTOFERRIN: ANALYSIS OF THE STRUCTURE PROFILE
Directory of Open Access Journals (Sweden)
Lilia Anghel
2014-12-01
Full Text Available The multitude of physiological processes in which the binding of iron ions takes part makes its mechanism worth investigating. The multiple sequence alignment method was applied to investigate the structure similarities of five lactoferrin X-ray crystallographic structures and outline the differences and similarities between lactoferrin and serum transferrin. The results of this study provide useful insights into the mechanism of iron-binding of lactoferrin protein molecule.
Energy Technology Data Exchange (ETDEWEB)
Crooker, S. A.; Kelley, M. R.; Martinez, N. J. D.; Nie, W.; Mohite, A.; Nayyar, I. H.; Tretiak, S.; Smith, D. L. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Liu, F.; Ruden, P. P. [University of Minnesota, Minneapolis, Minnesota 55455 (United States)
2014-10-13
We use spectrally resolved magneto-electroluminescence (EL) measurements to study the energy dependence of hyperfine interactions between polaron and nuclear spins in organic light-emitting diodes. Using layered devices that generate bright exciplex emission, we show that the increase in EL emission intensity I due to small applied magnetic fields of order 100 mT is markedly larger at the high-energy blue end of the EL spectrum (ΔI/I ∼ 11%) than at the low-energy red end (∼4%). Concurrently, the widths of the magneto-EL curves increase monotonically from blue to red, revealing an increasing hyperfine coupling between polarons and nuclei and directly providing insight into the energy-dependent spatial extent and localization of polarons.
Vyvey, K; Cottenier, S; Balabanski, D L; Coulier, N; Coussement, R; Georgiev, G; Lépine-Szily, A; Ternier, S; Teughels, S
2001-01-01
An extension of the time-integrated atomic decoupling technique to measure g-factors of (sub)nanosecond isomers and/or the magnetic hyperfine field induced by highly excited atomic electrons on nuclei recoiling into vacuum is discussed. A high average field B sub h sub f =1080 sub - sub 1 sub 7 sub 5 sup + sup 2 sup 7 sup 0 T and an average atomic spin J=2.7(2) is deduced using the known magnetic moment of a 4.05(7) mu s isomer in sup 6 sup 9 Ge. Such high magnetic fields allow g-factor measurements of (sub)nanosecond states. Ab initio calculations show that the combination of a high average magnetic hyperfine field and a high average atomic spin is only possible if a considerable fraction of the ions is in a metastable excited state.
Energy Technology Data Exchange (ETDEWEB)
Kim, Jonsik [Stony Brook Univ., NY (United States); Middlemiss, Derek S. [Stony Brook Univ., NY (United States); Chernova, Natasha [Univ. of Cambridge (United Kingdom); Zhu, Ben Y.H. [Stony Brook Univ., NY (United States); Masquelier, Christian [SUNY Binghamton, NY (United States); Grey, Clare P. [Stony Brook Univ., NY (United States); Universite de Picardie Jules Verne, Amiens (France)
2010-11-05
Iron phosphates (FePO_{4}) are among the most promising candidate materials for advanced Li-ion battery cathodes. This work reports upon a combined nuclear magnetic resonance (NMR) experimental and periodic density functional theory (DFT) computational study of the environments and electronic structures occurring in a range of paramagnetic Fe(III) phosphates comprising FePO_{4} (heterosite), monoclinic Li_{3}Fe_{2}(PO_{4})_{3} (anti-NASICON A type), rhombohedral Li_{3}Fe_{2}(PO_{4})_{3} (NASICON B type), LiFeP_{2}O_{7}, orthorhombic FePO_{4}·2H_{2}O (strengite), monoclinic FePO_{4}·2H_{2}O (phosphosiderite), and the dehydrated forms of the latter two phases. Many of these materials serve as model compounds relevant to battery chemistry. The ^{31}P spin-echo mapping and ^{7}Li magic angle spinning NMR techniques yield the hyperfine shifts of the species of interest, complemented by periodic hybrid functional DFT calculations of the respective hyperfine and quadrupolar tensors. A Curie-Weiss-based magnetic model scaling the DFT-calculated hyperfine parameters from the ferromagnetic into the experimentally relevant paramagnetic state is derived and applied, providing quantitative finite temperature values for each phase. The sensitivity of the hyperfine parameters to the composition of the DFT exchange functional is characterized by the application of hybrid Hamiltonians containing admixtures 0%, 20%, and 35% of Fock exchange. Good agreement between experimental and calculated values is obtained, provided that the residual magnetic couplings persisting in the paramagnetic state are included. The potential applications of a similar combined experimental and theoretical NMR approach to a wider range of cathode materials are discussed.
2014-09-18
between the 5s electron and the silver nucleus. Breit and Rabi [5] described this hyperfine interaction in the context of the Stern-Gerlach...experiment, and Rabi et al. [6] were the first to directly measure nuclear magnetic moments with this beam technique [7]. 1 quantum angular momentum or spin...is an interruption in the periodicity of a crystal lattice that is localized within a few lattice sites. A crystal lattice is composed of a Bravais
DEFF Research Database (Denmark)
Hansen, P. E.; Nevald, Rolf; Guggenheim, H. G.
1978-01-01
The isotropic and anisotropic transferred hyperfine interactions between F ions in the two chemically inequivalent sites and the rare-earth ions (R) have been derived from 19F NMR measurements in the temperature region 100-300 K on single crystals of TbF3 and DyF3. The isotropic interactions are ...... to vary only slightly with temperature. They are further assigned to definite R's in the unit cell, which cannot be done from macroscopic magnetic measurements....
Structural Configuration Systems Analysis for Advanced Aircraft Fuselage Concepts
Mukhopadhyay, Vivek; Welstead, Jason R.; Quinlan, Jesse R.; Guynn, Mark D.
2016-01-01
Structural configuration analysis of an advanced aircraft fuselage concept is investigated. This concept is characterized by a double-bubble section fuselage with rear mounted engines. Based on lessons learned from structural systems analysis of unconventional aircraft, high-fidelity finite-element models (FEM) are developed for evaluating structural performance of three double-bubble section configurations. Structural sizing and stress analysis are applied for design improvement and weight reduction. Among the three double-bubble configurations, the double-D cross-section fuselage design was found to have a relatively lower structural weight. The structural FEM weights of these three double-bubble fuselage section concepts are also compared with several cylindrical fuselage models. Since these fuselage concepts are different in size, shape and material, the fuselage structural FEM weights are normalized by the corresponding passenger floor area for a relative comparison. This structural systems analysis indicates that an advanced composite double-D section fuselage may have a relative structural weight ratio advantage over a conventional aluminum fuselage. Ten commercial and conceptual aircraft fuselage structural weight estimates, which are empirically derived from the corresponding maximum takeoff gross weight, are also presented and compared with the FEM- based estimates for possible correlation. A conceptual full vehicle FEM model with a double-D fuselage is also developed for preliminary structural analysis and weight estimation.
Exploiting Genome Structure in Association Analysis
Kim, Seyoung
2014-01-01
Abstract A genome-wide association study involves examining a large number of single-nucleotide polymorphisms (SNPs) to identify SNPs that are significantly associated with the given phenotype, while trying to reduce the false positive rate. Although haplotype-based association methods have been proposed to accommodate correlation information across nearby SNPs that are in linkage disequilibrium, none of these methods directly incorporated the structural information such as recombination events along chromosome. In this paper, we propose a new approach called stochastic block lasso for association mapping that exploits prior knowledge on linkage disequilibrium structure in the genome such as recombination rates and distances between adjacent SNPs in order to increase the power of detecting true associations while reducing false positives. Following a typical linear regression framework with the genotypes as inputs and the phenotype as output, our proposed method employs a sparsity-enforcing Laplacian prior for the regression coefficients, augmented by a first-order Markov process along the sequence of SNPs that incorporates the prior information on the linkage disequilibrium structure. The Markov-chain prior models the structural dependencies between a pair of adjacent SNPs, and allows us to look for association SNPs in a coupled manner, combining strength from multiple nearby SNPs. Our results on HapMap-simulated datasets and mouse datasets show that there is a significant advantage in incorporating the prior knowledge on linkage disequilibrium structure for marker identification under whole-genome association. PMID:21548809
RNAmute: RNA secondary structure mutation analysis tool
Directory of Open Access Journals (Sweden)
Barash Danny
2006-04-01
Full Text Available Abstract Background RNAMute is an interactive Java application that calculates the secondary structure of all single point mutations, given an RNA sequence, and organizes them into categories according to their similarity with respect to the wild type predicted structure. The secondary structure predictions are performed using the Vienna RNA package. Several alternatives are used for the categorization of single point mutations: Vienna's RNAdistance based on dot-bracket representation, as well as tree edit distance and second eigenvalue of the Laplacian matrix based on Shapiro's coarse grain tree graph representation. Results Selecting a category in each one of the processed tables lists all single point mutations belonging to that category. Selecting a mutation displays a graphical drawing of the single point mutation and the wild type, and includes basic information such as associated energies, representations and distances. RNAMute can be used successfully with very little previous experience and without choosing any parameter value alongside the initial RNA sequence. The package runs under LINUX operating system. Conclusion RNAMute is a user friendly tool that can be used to predict single point mutations leading to conformational rearrangements in the secondary structure of RNAs. In several cases of substantial interest, notably in virology, a point mutation may lead to a loss of important functionality such as the RNA virus replication and translation initiation because of a conformational rearrangement in the secondary structure.
Structure learning by pruning in independent component analysis
DEFF Research Database (Denmark)
Nielsen, Andreas Brinch; Hansen, Lars Kai
2008-01-01
We discuss pruning as a means of structure learning in independent component analysis (ICA). Learning the structure is attractive in both signal processing and in analysis of abstract data, where it can assist model interpretation, generalizability and reduce computation. We derive the relevant...
Vibration Analysis of Structures with Rotation and Reflection Symmetry
Directory of Open Access Journals (Sweden)
Baojian Li
1996-01-01
Full Text Available The article applies group representation theory to the vibration analysis of structures with Cnv symmetry, and presents a new structural vibration analysis method. The eigenvalue problem of the whole structure is divided into much smaller subproblems by forming the mass and stiffness matrices of one substructure and than modifying them to form mass and stiffness matrices in each irreducible subspace, resulting in the saving of computer time and memory. The modal characteristics of structures with Cnv symmetry are derived from theoretical analysis. Computation and modal testing are used to verify the validity of the theoretical deductions.
Structural analysis with the finite element method linear statics
Oñate, Eugenio
2013-01-01
STRUCTURAL ANALYSIS WITH THE FINITE ELEMENT METHOD Linear Statics Volume 1 : The Basis and Solids Eugenio Oñate The two volumes of this book cover most of the theoretical and computational aspects of the linear static analysis of structures with the Finite Element Method (FEM). The content of the book is based on the lecture notes of a basic course on Structural Analysis with the FEM taught by the author at the Technical University of Catalonia (UPC) in Barcelona, Spain for the last 30 years. Volume1 presents the basis of the FEM for structural analysis and a detailed description of the finite element formulation for axially loaded bars, plane elasticity problems, axisymmetric solids and general three dimensional solids. Each chapter describes the background theory for each structural model considered, details of the finite element formulation and guidelines for the application to structural engineering problems. The book includes a chapter on miscellaneous topics such as treatment of inclined supports, elas...
Structural Reliability Analysis of Wind Turbines: A Review
Directory of Open Access Journals (Sweden)
Zhiyu Jiang
2017-12-01
Full Text Available The paper presents a detailed review of the state-of-the-art research activities on structural reliability analysis of wind turbines between the 1990s and 2017. We describe the reliability methods including the first- and second-order reliability methods and the simulation reliability methods and show the procedure for and application areas of structural reliability analysis of wind turbines. Further, we critically review the various structural reliability studies on rotor blades, bottom-fixed support structures, floating systems and mechanical and electrical components. Finally, future applications of structural reliability methods to wind turbine designs are discussed.
Experiment for the first direct measurement of the hyperfine splitting of positronium
Energy Technology Data Exchange (ETDEWEB)
Miyazaki, A; Ishida, A; Asai, S [Department of Physics, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 133-0033 (Japan); Suehara, T; Namba, T; Kobayashi, T [International Center for Elementary Particle Physics (ICEPP), The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 (Japan); Saito, H [Department of General Systems Studies, Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo, 153-8902 (Japan); Yoshida, M [Accelerator Laboratory, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki, 305-0801 (Japan); Idehara, T; Ogawa, I; Urushizaki, Y [Research Center for Development of Far-Infrared Region, University of Fukui (FIR-FU), 3-9-1 Bunkyo, Fukui, Fukui, 910-8507 (Japan); Sabchevski, S, E-mail: miyazaki@icepp.s.u-tokyo.ac.j [Bulgarian Academy of Science, 1, 15 Noemvri Str., 1040 Sofia (Bulgaria)
2010-04-01
Positronium is an ideal system for the research of the bound state QED. The hyperfine splitting of positronium (Ps-HFS: about 203 GHz) is a good tool to test QED and also sensitive to new physics beyond the Standard Model via a quantum oscillation between an ortho-Ps and a virtual photon. Previous experimental results show 3.9 {sigma} (15 ppm) discrepancy from the QED calculation. All previous experiments used an indirect method with static magnetic field to cause Zeeman splitting (a few GHz) between triplet states of ortho-Ps, from which the HFS value was derived. One possible systematic error source of the indirect method is non-uniformity of the static magnetic field. We are developing a new direct Ps-HFS measurement system without static magnetic field. In this measurement we use a gyrotron, a novel sub-THz light source, with a high-finesse Fabry-Perot cavity to obtain enough radiation power at 203 GHz. The present status of the optimization studies and current design of the experiment are described.
Leggett-Garg inequalities violation via the Fermi contact hyperfine interaction
Energy Technology Data Exchange (ETDEWEB)
Lobejko, Marcin; Dajka, Jerzy [Institute of Physics, University of Silesia, Katowice (Poland); Silesian Center for Education and Interdisciplinary Research, University of Silesia, Chorzow (Poland)
2017-06-15
In this paper we examine theoretically how the spin-spin interaction between a nuclei and an electron in the atom affects violation of the Leggett-Garg inequalities. We consider the simplest case of atoms in the {sup 2}S{sub 1/2} state that in the valence shell have just a single electron and the evolution in time of the spin is dictated only by the Fermi contact hyperfine interaction. We found that for special initial conditions and a particular measured observable the high spin nucleus couple to the valence electron such that violation of Leggett-Garg inequalities increases with total spin of states. Consequently, our results show that for the Hydrogen, the smallest atom in Nature, the violation of the Leggett-Garg inequalities is the smallest whereas for the largest atom, the Cesium, the violation is the largest. Moreover, this violation does not depend on a principal quantum number, thus our model can be used for Rydberg atoms in order to test macrorealism for 'almost macroscopic' objects. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Computer applications for engineering/structural analysis. Revision 1
Energy Technology Data Exchange (ETDEWEB)
Zaslawsky, M.; Samaddar, S.K.
1991-12-31
Analysts and organizations have a tendency to lock themselves into specific codes with the obvious consequences of not addressing the real problem and thus reaching the wrong conclusion. This paper discusses the role of the analyst in selecting computer codes. The participation and support of a computation division in modifying the source program, configuration management, and pre- and post-processing of codes are among the subjects discussed. Specific examples illustrating the computer code selection process are described in the following problem areas: soil structure interaction, structural analysis of nuclear reactors, analysis of waste tanks where fluid structure interaction is important, analysis of equipment, structure-structure interaction, analysis of the operation of the superconductor supercollider which includes friction and transient temperature, and 3D analysis of the 10-meter telescope being built in Hawaii. Validation and verification of computer codes and their impact on the selection process are also discussed.
Meta-analysis a structural equation modeling approach
Cheung, Mike W-L
2015-01-01
Presents a novel approach to conducting meta-analysis using structural equation modeling. Structural equation modeling (SEM) and meta-analysis are two powerful statistical methods in the educational, social, behavioral, and medical sciences. They are often treated as two unrelated topics in the literature. This book presents a unified framework on analyzing meta-analytic data within the SEM framework, and illustrates how to conduct meta-analysis using the metaSEM package in the R statistical environment. Meta-Analysis: A Structural Equation Modeling Approach begins by introducing the impo
Theses "Discussion" Sections: A Structural Move Analysis
Nodoushan, Mohammad Ali Salmani; Khakbaz, Nafiseh
2011-01-01
The current study aimed at finding the probable differences between the move structure of Iranian MA graduates' thesis discussion subgenres and those of their non-Iranian counterparts, on the one hand, and those of journal paper authors, on the other. It also aimed at identifying the moves that are considered obligatory, conventional, or optional…
Reliability Analysis of an Offshore Structure
DEFF Research Database (Denmark)
Sørensen, John Dalsgaard; Rackwitz, R.; Thoft-Christensen, Palle
1992-01-01
For an offshore structure in the North Sea it is assumed that information from measurements and inspections is available. As illustrations measurements of the significant wave height and the marine growth and different inspection and repair results are considered. It is shown how the reliability...
Structure function analysis of mammalian cryptochromes
F. Tamanini (Filippo); I. Chaves (Ines); M.I. Bajek (Monika); G.T.J. van der Horst (Gijsbertus)
2007-01-01
textabstractMembers of the photolyase/cryptochrome family are flavoproteins that share an extraordinary conserved core structure (photolyase homology region, PHR), but the presence of a carboxy-terminal extension is limited to the cryptochromes. Photolyases are DNA-repair enzymes that remove
‘Designerly’ Analysis of Participation Structures
DEFF Research Database (Denmark)
Buur, Jacob; Beuthel, Maria Rosa; Caglio, Agnese
2013-01-01
With the inclusion of not only users but stake-holders of many different kinds, design processes turn into complex collaborative challenges. Thus, improving design practices requires research into how people participate and contribute in social interaction. But research methods for understand-ing......: the participatory structures....
RNA Structural Analysis by Evolving SHAPE Chemistry
Spitale, Robert C.; Flynn, Ryan A.; Torre, Eduardo A.; Kool, Eric T.; Chang, Howard Y.
2017-01-01
RNA is central to the flow of biological information. From transcription to splicing, RNA localization, translation, and decay, RNA is intimately involved in regulating every step of the gene expression program, and is thus essential for health and understanding disease. RNA has the unique ability to base-pair with itself and other nucleic acids to form complex structures. Hence the information content in RNA is not simply its linear sequence of bases, but is also encoded in complex folding of RNA molecules. A general chemical functionality that all RNAs have is a 2’-hydroxyl group in the ribose ring, and the reactivity of the 2'-hydroxyl in RNA is gated by local nucleotide flexibility. In other words, the 2'-hydroxyl is reactive at single-stranded and conformationally flexible positions but is unreactive at nucleotides constrained by base pairing. Recent efforts have been focused on developing reagents that modify RNA as a function of RNA 2’ hydroxyl group flexibility. Such RNA structure probing techniques can be read out by primer extension in experiments termed RNA SHAPE (Selective 2’ Hydroxyl Acylation and Primer Extension). Herein we describe the efforts devoted to the design and utilization of SHAPE probes for characterizing RNA structure. We also describe current technological advances that are being used to utilize SHAPE chemistry with deep sequencing to probe many RNAs in parallel. The merger of chemistry with genomics is sure to open the door to genome-wide exploration of RNA structure and function. PMID:25132067
Structural Analysis of a Dragonfly Wing
Jongerius, S.R.; Lentink, D.
2010-01-01
Dragonfly wings are highly corrugated, which increases the stiffness and strength of the wing significantly, and results in a lightweight structure with good aerodynamic performance. How insect wings carry aerodynamic and inertial loads, and how the resonant frequency of the flapping wings is tuned
Total-System Approach To Design And Analysis Of Structures
Verderaime, V.
1995-01-01
Paper presents overview and study of, and comprehensive approach to, multidisciplinary engineering design and analysis of structures. Emphasizes issues related to design of semistatic structures in environments in which spacecraft launched, underlying concepts applicable to other structures within unique terrestrial, marine, or flight environments. Purpose of study to understand interactions among traditionally separate engineering design disciplines with view toward optimizing not only structure but also overall design process.
Superconducting metamaterial resonators: analysis of mode structure
Wang, Haozhi; Hutchings, Matthew; Indrajeet, Sagar; Rouxinol, Francisco; Lahaye, Matthew; Plourde, B. L. T.; Taketani, Bruno G.; Wilhelm, Frank K.; Zhuravel, Alexander; Ustinov, Alexey
Metamaterial transmission line resonators fabricated from superconducting thin films exhibit novel mode spectra that can be used for multi-mode experiments with superconducting qubits. For certain configurations of the circuit elements, these structures have a dispersion relation that is a falling function of wavenumber, leading to a high density of narrow modes in the typical frequency range of transmon qubits. We present Laser Scanning Microscope images of the microwave current distribution while driving the various metamaterial resonances and we compare these with numerical simulations of the microwave behavior of these structures, including the effects of stray reactances in the circuit elements. We demonstrate that the wavelength of the metamaterial modes in fact grows with increasing frequency, characteristic of a left-handed system.
Fluid Structure Interaction Analysis of Planar Buoy
Patel, Rakeshbhai; Hanif, Muhammad Adnan; Oad, Rajev Kumar
2011-01-01
Different types of wave energy convertors are being studied using the heave motion of floating bodies to generate electricity. In this thesis, we investigate the interaction of floating buoys from hydrodynamic point of view. The dynamic heave response of buoy under two different load cases and represented by single degree of freedom model is studied. The fluid-structure interactions based on 2-dimensional linear potential flow theory were modeled and simulated using finite element method. The...
Structural Analysis of a Dragonfly Wing
Jongerius, S.R.; Lentink, D.
2010-01-01
Dragonfly wings are highly corrugated, which increases the stiffness and strength of the wing significantly, and results in a lightweight structure with good aerodynamic performance. How insect wings carry aerodynamic and inertial loads, and how the resonant frequency of the flapping wings is tuned for carrying these loads, is however not fully understood. To study this we made a three-dimensional scan of a dragonfly (Sympetrum vulgatum) fore- and hindwing with a micro-CT scanner. The scans c...
Synthesis, crystal structure, thermal analysis and dielectric ...
Indian Academy of Sciences (India)
providing information about the complete crystal structure at room temperature of the new compounds. These materi- ... Data collection instrument. Kappa-APEX II. Kappa-APEX II. Radiation, graphite ..... graphic method of the mixed compounds K0.57(NH4)0.43CdCl3 and K0.25(NH4)0.75CdCl3. This study is restricted to ...
Structural analysis with high brilliance synchrotron radiation
Energy Technology Data Exchange (ETDEWEB)
Ohno, Hideo [Japan Atomic Energy Research Inst., Kamigori, Hyogo (Japan). Kansai Research Establishment
1997-11-01
The research subjects in diffraction and scattering of materials with high brilliance synchrotron radiation such as SPring-8 (Super Photon ring 8 GeV) are summarized. The SPring-8 project is going well and 10 public beamlines will be opened for all users in October, 1997. Three JAERI beamlines are also under construction for researches of heavy element science, physical and structural properties under extreme conditions such as high temperature and high pressure. (author)
Design and analysis of composite structures with applications to aerospace structures
Kassapoglou, Christos
2010-01-01
Design and Analysis of Composite Structures enables graduate students and engineers to generate meaningful and robust designs of complex composite structures. Combining analysis and design methods for structural components, the book begins with simple topics such as skins and stiffeners and progresses through to entire components of fuselages and wings. Starting with basic mathematical derivation followed by simplifications used in real-world design, Design and Analysis of Composite Structures presents the level of accuracy and range of applicability of each method. Examples taken from ac
Acoustic Emission Analysis of Prestressed Concrete Structures
Elfergani, H. A.; Pullin, R.; Holford, K. M.
2011-07-01
Corrosion is a substantial problem in numerous structures and in particular corrosion is very serious in reinforced and prestressed concrete and must, in certain applications, be given special consideration because failure may result in loss of life and high financial cost. Furthermore corrosion cannot only be considered a long term problem with many studies reporting failure of bridges and concrete pipes due to corrosion within a short period after they were constructed. The concrete pipes which transport water are examples of structures that have suffered from corrosion; for example, the pipes of The Great Man-Made River Project of Libya. Five pipe failures due to corrosion have occurred since their installation. The main reason for the damage is corrosion of prestressed wires in the pipes due to the attack of chloride ions from the surrounding soil. Detection of the corrosion in initial stages has been very important to avoid other failures and the interruption of water flow. Even though most non-destructive methods which are used in the project are able to detect wire breaks, they cannot detect the presence of corrosion. Hence in areas where no excavation has been completed, areas of serious damage can go undetected. Therefore, the major problem which faces engineers is to find the best way to detect the corrosion and prevent the pipes from deteriorating. This paper reports on the use of the Acoustic Emission (AE) technique to detect the early stages of corrosion prior to deterioration of concrete structures.
Energy Technology Data Exchange (ETDEWEB)
Leite Neto, Osmar Flavio da Silveira
2014-07-01
The use o nanoparticles in current medicine are under intense investigation. The possible advantages proposed by these systems are very impressive and the results may be quite schemer. In this scenario, the association of nanoparticles with radioactive materials (radionuclide) may be the most important step since the discovery of radioactive for nuclear medicine and radiopharmacy, especially for cancer targeting and therapy. The hyperfine interaction of the nuclear probe {sup 111}Cd in the Hydroxyapatite compounds has been investigated by perturbed angular correlation (PAC) spectroscopy in room temperature for the hydroxyapatite made in the temperatures of 90°C, 35°C and with Ho doped, both thermalized and not. The thermalized samples were heated to T= 1273 K for 6 h. The {sup 111}Cd was broadcast in the structure of the material by diffusion, closing in quartz tubes were heated – together with the radioactive PAC probe {sup 111}In/{sup 111}Cd to T = 1073 K for 12 h. In not thermalized samples the PAC spectra indicate a distribution of frequency, but in the thermalized samples, the PAC spectra shows the presence of β-tri calcium phosphate in the structure of this kind of Hydroxyapatite. (author)
Mahato, Dip Narayan
This thesis includes x-ray experiments for medical and materials applications and the use of x-ray diffraction data in a first-principles study of electronic structures and hyperfine properties of chemical and biological systems. Polycapillary focusing lenses were used to collect divergent x rays emitted from conventional x-ray tubes and redirect them to form an intense focused beam. These lenses are routinely used in microbeam x-ray fluorescence analysis. In this thesis, their potential application to powder diffraction and focused beam orthovoltage cancer therapy has been investigated. In conventional x-ray therapy, very high energy (˜ MeV) beams are used, partly to reduce the skin dose. For any divergent beam, the dose is necessarily highest at the entry point, and decays exponentially into the tissue. To reduce the skin dose, high energy beams, which have long absorption lengths, are employed, and rotated about the patient to enter from different angles. This necessitates large expensive specialized equipment. A focused beam could concentrate the dose within the patient. Since this is inherently skin dose sparing, lower energy photons could be employed. A primary concern in applying focused beams to therapy is whether the focus would be maintained despite Compton scattering within the tissue. To investigate this, transmission and focal spot sizes as a function of photon energy of two polycapillary focusing lenses were measured. The effects of tissue-equivalent phantoms of different thicknesses on the focal spot size were studied. Scatter fraction and depth dose were calculated. For powder diffraction, the polycapillary optics provide clean Gaussian peaks, which result in angular resolution that is much smaller than the peak width due to the beam convergence. Powder diffraction (also called coherent scatter) without optics can also be used to distinguish between tissue types that, because they have different nanoscale structures, scatter at different angles
Gonçalves, J N; Correia, J G; Lopes, A M L
2011-01-01
The MnAs compound shows a first-order transition at T$_{c}$≈ 42$^{\\circ}$C, and a second-order transition at T$_{t}$ ≈120$^{\\circ}$C. The first-order transition, with structural (hexagonal-orthorhombic), magnetic (FM-PM) and electrical conductivity changes, is associated to magnetocaloric, magnetoelastic, and magnetoresistance effects. We report a study in a large temperature range from −196$^{\\circ}$C up to 140$^{\\circ}$C, using the $\\gamma\\!-\\!\\gamma$ perturbed angular correlations method with the radioactive probe $^{77}$Br→$^{77}$Se, produced at the ISOLDE-CERN facility. The electric field gradients and magnetic hyperfine fields are determined across the first- and second-order phase transitions encompassing the pure and mixed phase regimes in cooling and heating cycles. The temperature irreversibility of the 1st order phase transition is seen locally, at the nanoscopic scale sensitivity of the hyperfine field, by its hysteresis, detailing and complementing information obtained with macroscopic me...
Large-scale structural analysis: The structural analyst, the CSM Testbed and the NAS System
Knight, Norman F., Jr.; Mccleary, Susan L.; Macy, Steven C.; Aminpour, Mohammad A.
1989-01-01
The Computational Structural Mechanics (CSM) activity is developing advanced structural analysis and computational methods that exploit high-performance computers. Methods are developed in the framework of the CSM testbed software system and applied to representative complex structural analysis problems from the aerospace industry. An overview of the CSM testbed methods development environment is presented and some numerical methods developed on a CRAY-2 are described. Selected application studies performed on the NAS CRAY-2 are also summarized.
Population genetic structure analysis in endangered Hordeum ...
African Journals Online (AJOL)
Inbreeding index, gene flow values and cluster analysis revealed also significant differentiation between all populations. Gene flow decreased rapidly as the geographic distance increased. This may imply that seed exchange between farmers was limited to a regional scale. The lower correlation between the Euclidean ...
Isogeometric analysis for thin-walled composite structures
Guo, Y.
2016-01-01
The conceptual ideas behind isogeometric analysis (IGA) are aimed at unifying computer aided design (CAD) and finite element analysis (FEA). Isogeometric analysis employs the non-uniform rational B-spline functions (NURBS) used for the geometric description of a structure to approximate its physical
Reliability analysis of an offshore structure
DEFF Research Database (Denmark)
Faber, Michael Havbro; Sørensen, John Dalsgaard; Rackwitz, R.
1992-01-01
A jacket type offshore structure from the North Sea is considered. The time variant reliability is estimated for failure defined as brittle fracture and crack through the tubular member walls. The stochastic modelling is described. The hot spot stress spectral moments as function of the stochastic...... variables are described using spline function response surfaces. A Laplace integral expansion is used to estimate the time variant reliability. Parameter studies are performed for the reliability estimates and the results of the time variant and the time invariant reliability analyses are compared. (Authors)...
Reliability Analysis of an Offshore Structure
DEFF Research Database (Denmark)
Sørensen, John Dalsgaard; Thoft-Christensen, Palle; Rackwitz, R.
1992-01-01
A jacket type offshore structure from the North Sea is considered. The time variant reliability is estimated for failure defined as brittie fradure and crack through the tubular roerober walls. The stochastic modeiling is described. The hot spot stress speetral moments as fundion of the stochastic...... variables are desenbed using spline fundion response surfaces. A Laplace integral expansion is used to estimate the time variant reliability. Parameter studies are performed for the reliability estimates and the results of the time variant and the time invariant reliability analyses are compared....
Structural analysis of hierarchically organized zeolites
Mitchell, Sharon; Pinar, Ana B.; Kenvin, Jeffrey; Crivelli, Paolo; Kärger, Jörg; Pérez-Ramírez, Javier
2015-01-01
Advances in materials synthesis bring about many opportunities for technological applications, but are often accompanied by unprecedented complexity. This is clearly illustrated by the case of hierarchically organized zeolite catalysts, a class of crystalline microporous solids that has been revolutionized by the engineering of multilevel pore architectures, which combine unique chemical functionality with efficient molecular transport. Three key attributes, the crystal, the pore and the active site structure, can be expected to dominate the design process. This review examines the adequacy of the palette of techniques applied to characterize these distinguishing features and their catalytic impact. PMID:26482337
Protein structure similarity from principle component correlation analysis
Directory of Open Access Journals (Sweden)
Chou James
2006-01-01
Full Text Available Abstract Background Owing to rapid expansion of protein structure databases in recent years, methods of structure comparison are becoming increasingly effective and important in revealing novel information on functional properties of proteins and their roles in the grand scheme of evolutionary biology. Currently, the structural similarity between two proteins is measured by the root-mean-square-deviation (RMSD in their best-superimposed atomic coordinates. RMSD is the golden rule of measuring structural similarity when the structures are nearly identical; it, however, fails to detect the higher order topological similarities in proteins evolved into different shapes. We propose new algorithms for extracting geometrical invariants of proteins that can be effectively used to identify homologous protein structures or topologies in order to quantify both close and remote structural similarities. Results We measure structural similarity between proteins by correlating the principle components of their secondary structure interaction matrix. In our approach, the Principle Component Correlation (PCC analysis, a symmetric interaction matrix for a protein structure is constructed with relationship parameters between secondary elements that can take the form of distance, orientation, or other relevant structural invariants. When using a distance-based construction in the presence or absence of encoded N to C terminal sense, there are strong correlations between the principle components of interaction matrices of structurally or topologically similar proteins. Conclusion The PCC method is extensively tested for protein structures that belong to the same topological class but are significantly different by RMSD measure. The PCC analysis can also differentiate proteins having similar shapes but different topological arrangements. Additionally, we demonstrate that when using two independently defined interaction matrices, comparison of their maximum
Structural and quantitative analysis of Equisetum alkaloids.
Cramer, Luise; Ernst, Ludger; Lubienski, Marcus; Papke, Uli; Schiebel, Hans-Martin; Jerz, Gerold; Beuerle, Till
2015-08-01
Equisetum palustre L. is known for its toxicity for livestock. Several studies in the past addressed the isolation and identification of the responsible alkaloids. So far, palustrine (1) and N(5)-formylpalustrine (2) are known alkaloids of E. palustre. A HPLC-ESI-MS/MS method in combination with simple sample work-up was developed to identify and quantitate Equisetum alkaloids. Besides the two known alkaloids six related alkaloids were detected in different Equisetum samples. The structure of the alkaloid palustridiene (3) was derived by comprehensive 1D and 2D NMR experiments. N(5)-Acetylpalustrine (4) was also thoroughly characterized by NMR for the first time. The structure of N(5)-formylpalustridiene (5) is proposed based on mass spectrometry results. Twenty-two E. palustre samples were screened by a HPLC-ESI-MS/MS method after development of a simple sample work-up and in most cases the set of all eight alkaloids were detected in all parts of the plant. A high variability of the alkaloid content and distribution was found depending on plant organ, plant origin and season ranging from 88 to 597mg/kg dried weight. However, palustrine (1) and the alkaloid palustridiene (3) always represented the main alkaloids. For the first time, a comprehensive identification, quantitation and distribution of Equisetum alkaloids was achieved. Copyright © 2015 Elsevier Ltd. All rights reserved.
Bumper Stickers in Jordan: A Structural Analysis
Directory of Open Access Journals (Sweden)
Husam Al-Momani
2017-08-01
Full Text Available This study has set out to determine the structural patterns of bumper stickers in Jordan. This study is significant since it is the first one to approach bumper stickers structurally. The study has investigated 227 stickers, which can be considered the corpus of stickers in Jordan. The study has found that around 90% of the stickers are sentences, most of which are simple sentences expressed in the present tense. This combination of the three elements i.e. sentence, declarative and simple is what facilitated the job of drivers to write their opinions, attitudes, beliefs, etc. and is what made it possible for the others i.e. drivers and pedestrians to understand the stickers. The study has also found that imperative and negative imperatives are quite common since the stickers are not addressed to the writer/driver rather to the others so as to inform them about his state, his miserable condition, his opinions, his loyalties, and his vehicle. The stickers are addressed to others to demand certain behaviors from them such as driving wisely, not challenging the sticker writer, respecting him if he is driving a truck or a lorry, etc.
[Molecular structure and fractal analysis of oligosaccharide].
Liu, Wen-long; Wang, Lu-man; He, Dong-qi; Zhang, Tian-lan; Gou, Bao-di; Li, Qing
2014-10-18
To propose a calculation method of oligosaccharides' fractal dimension, and to provide a new approach to studying the drug molecular design and activity. By using the principle of energy optimization and computer simulation technology, the steady structures of oligosaccharides were found, and an effective way of oligosaccharides fractal dimension's calculation was further established by applying the theory of box dimension to the chemical compounds. By using the proposed method, 22 oligosaccharides' fractal dimensions were calculated, with the mean 1.518 8 ± 0.107 2; in addition, the fractal dimensions of the two activity multivalent oligosaccharides which were confirmed by experiments, An-2 and Gu-4, were about 1.478 8 and 1.516 0 respectively, while C-type lectin-like receptor Dectin-1's fractal dimension was about 1.541 2. The experimental and computational results were expected to help to find a class of glycoside drugs whose target receptor was Dectin-1. Fractal dimension, differing from other known macro parameters, is a useful tool to characterize the compound molecules' microscopic structure and function, which may play an important role in the molecular design and biological activity study. In the process of oligosaccharides drug screening, the fractal dimension of receptor and designed oligosaccharides or glycoclusters can be calculated respectively. The oligosaccharides with fractal dimension close to that of target receptor should then take priority compared with others, to get the drug molecules with latent activity.
Structural dynamic analysis of a ball joint
Hwang, Seok-Cheol; Lee, Kwon-Hee
2012-11-01
Ball joint is a rotating and swiveling element that is typically installed at the interface between two parts. In an automobile, the ball joint is the component that connects the control arms to the steering knuckle. The ball joint can also be installed in linkage systems for motion control applications. This paper describes the simulation strategy for a ball joint analysis, considering manufacturing process. Its manufacturing process can be divided into plugging and spinning. Then, the interested responses is selected as the stress distribution generated between its ball and bearing. In this paper, a commercial code of NX DAFUL using an implicit integration method is introduced to calculate the response. In addition, the gap analysis is performed to investigate the fitness, focusing on the response of the displacement of a ball stud. Also, the optimum design is suggested through case studies.
Strategies for Nonlinear Analysis of Marine Structures
1988-08-01
standard deviation, a 2 N linear damp# ing matrix Njk nonlinear dampiny matrix nx direction cosine P(x) cumulative probability or probability...3.4) and z (z) I f q(z) dz (3.5) The values of (z) are tabulated in many textbooks on mathematical statistics [e.g., Tobias and Trindade (1986...Tobias, P.A. and Trindade , D., Applied Reliability, Van Nostrand Reinhold Company, New York, 1986. NONLINEAR ANALYSIS 1. Burns, G.E., "Calculating
Structural analysis of ITER multi-purpose deployer
Energy Technology Data Exchange (ETDEWEB)
Manuelraj, Manoah Stephen, E-mail: manoah@ipr.res.in [Institute for Plasma Research, Gandhinagar, Gujarat 382428 (India); Dutta, Pramit; Gotewal, Krishan Kumar; Rastogi, Naveen [Institute for Plasma Research, Gandhinagar, Gujarat 382428 (India); Tesini, Alessandro [ITER Organization, Route de Vinon-sur-Verdon, CS 90046, 1306 St Paul lez Durance Cedex (France); Choi, Chang-Hwan, E-mail: chang-hwan.choi@iter.org [ITER Organization, Route de Vinon-sur-Verdon, CS 90046, 1306 St Paul lez Durance Cedex (France)
2016-11-01
Highlights: • System modelling for structural analysis of the Multi-Purpose Deployer (MPD). • Finite element modeling of the Multi-Purpose Deployer (MPD). • Static, modal and seismic response analysis of the Multi-Purpose Deployer (MPD). • Iterative structural analysis and design update to satisfy the structural criteria. • Modal analysis for various kinematic configurations. • Reaction force calculations on the interfacing systems. - Abstract: The Multi-Purpose Deployer (MPD) is a general purpose ITER in-vessel remote handling (RH) system. The main handling equipment, known as the MPD Transporter, consists of a series of linked bodies, which provide anchoring to the vacuum vessel port and an articulated multi-degree of freedom motion to perform various in-vessel maintenance tasks. During the in-vessel operations, the structural integrity of the system should be guaranteed against various operational and seismic loads. This paper presents the structural analysis results of the concept design of the MPD Transporter considering the seismic events. Static structural, modal and frequency response spectrum analyses have been performed to verify the structural integrity of the system, and to provide reaction forces to the interfacing systems such as vacuum vessel and cask. Iterative analyses and design updates are carried out based on the reference design of the system to improve the structural behavior of the system. The frequency responses of the system in various kinematics and payloads are assessed.
Wheat yield dynamics: a structural econometric analysis.
Sahin, Afsin; Akdi, Yilmaz; Arslan, Fahrettin
2007-10-15
In this study we initially have tried to explore the wheat situation in Turkey, which has a small-open economy and in the member countries of European Union (EU). We have observed that increasing the wheat yield is fundamental to obtain comparative advantage among countries by depressing domestic prices. Also the changing structure of supporting schemes in Turkey makes it necessary to increase its wheat yield level. For this purpose, we have used available data to determine the dynamics of wheat yield by Ordinary Least Square Regression methods. In order to find out whether there is a linear relationship among these series we have checked each series whether they are integrated at the same order or not. Consequently, we have pointed out that fertilizer usage and precipitation level are substantial inputs for producing high wheat yield. Furthermore, in respect for our model, fertilizer usage affects wheat yield more than precipitation level.
Structural shell analysis understanding and application
Blaauwendraad, Johan
2014-01-01
The mathematical description of the properties of a shell is much more elaborate than those of beam and plate structures. Therefore many engineers and architects are unacquainted with aspects of shell behaviour and design, and are not familiar with sufficiently reliable shell theories for the different shell types as derived in the middle of the 20th century. Rather than contributing to theory development, this university textbook focuses on architectural and civil engineering schools. Of course, practising professionals will profit from it as well. The book deals with thin elastic shells, in particular with cylindrical, conical and spherical types, and with elliptic and hyperbolic paraboloids. The focus is on roofs, chimneys, pressure vessels and storage tanks. Special attention is paid to edge bending disturbance zones, which is indispensable knowledge in FE meshing. A substantial part of the book results from research efforts in the mid 20th century at Delft University of Technology. As such, it is a valua...
Energy Technology Data Exchange (ETDEWEB)
Cordeiro, Moacir Ribeiro
2007-07-01
III the present work, a microscopic investigation of hyperfine interactions in single crystal silicon samples was carried out by means of Perturbed Angular {gamma} -{gamma} correlation technique (PAC), which is based in hyperfine interactions. In order to achieve these measurements, it was used {sup 111} In {yields} {sup 111}Cd radioactive probe nuclei, which decay through the well known {gamma} cascade 171-245 keV with an intermediate level of 245 keV ( I 5{sup +}/2, Q = 0.83b, T{sub 1/2} = 84.5 ns). The samples were prepared using different probe nuclei insertion methods, making possible to increase our understanding on the impact generated by each of these techniques in PAC measurements. Ion implantation, diffusion and evaporation were carefully investigated giving emphasis on its characteristics and particularities. Then, it was made a study about the concentration of intrinsic defects as function of severe annealing processes. Finally, a comparative analysis was made for all these probe nuclei insertion methods. This work also accomplished PAC measurements in single crystal silicon doped with phosphorus by means of Neutron Transmutation Doping (NTD) method, carried out in a research nuclear reactor. The extremely high doping uniformity allied to the nonexistence of previous measurements in these materials emphasize the importance of the results obtained. These results are then compared with literature results for samples doped by conventional methods presenting the respective conclusions. (author)
Reliability analysis of structures under periodic proof tests in service
Yang, J.-N.
1976-01-01
A reliability analysis of structures subjected to random service loads and periodic proof tests treats gust loads and maneuver loads as random processes. Crack initiation, crack propagation, and strength degradation are treated as the fatigue process. The time to fatigue crack initiation and ultimate strength are random variables. Residual strength decreases during crack propagation, so that failure rate increases with time. When a structure fails under periodic proof testing, a new structure is built and proof-tested. The probability of structural failure in service is derived from treatment of all the random variables, strength degradations, service loads, proof tests, and the renewal of failed structures. Some numerical examples are worked out.
Data analysis of asymmetric structures advanced approaches in computational statistics
Saito, Takayuki
2004-01-01
Data Analysis of Asymmetric Structures provides a comprehensive presentation of a variety of models and theories for the analysis of asymmetry and its applications and provides a wealth of new approaches in every section. It meets both the practical and theoretical needs of research professionals across a wide range of disciplines and considers data analysis in fields such as psychology, sociology, social science, ecology, and marketing. In seven comprehensive chapters this guide details theories, methods, and models for the analysis of asymmetric structures in a variety of disciplines and presents future opportunities and challenges affecting research developments and business applications.
Harris, Charles E.; Starnes, James H., Jr.; Newman, James C., Jr.
1995-01-01
NASA is developing a 'tool box' that includes a number of advanced structural analysis computer codes which, taken together, represent the comprehensive fracture mechanics capability required to predict the onset of widespread fatigue damage. These structural analysis tools have complementary and specialized capabilities ranging from a finite-element-based stress-analysis code for two- and three-dimensional built-up structures with cracks to a fatigue and fracture analysis code that uses stress-intensity factors and material-property data found in 'look-up' tables or from equations. NASA is conducting critical experiments necessary to verify the predictive capabilities of the codes, and these tests represent a first step in the technology-validation and industry-acceptance processes. NASA has established cooperative programs with aircraft manufacturers to facilitate the comprehensive transfer of this technology by making these advanced structural analysis codes available to industry.
Inverse Analysis of Cavitation Impact Phenomena on Structures
National Research Council Canada - National Science Library
Lambrakos, S. G; Tran, N. E
2007-01-01
A general methodology is presented for in situ detection of cavitation impact phenomena on structures based on inverse analysis of luminescent emissions resulting from the collapsing of bubbles onto surfaces...
Formation and Structural Analysis of Novel Dibornyl Ethers
African Journals Online (AJOL)
PROF P.T. KAYE
. SHORT COMMUNICATION. Formation and Structural Analysis of Novel Dibornyl Ethers. Perry T. Kaye*, Andrew R. Duggan, Joseph M. Matjila, Warner E. Molema, and. Swarnam S. Ravindran. Department of Chemistry, Rhodes University, Grahamstown, ...
STRUCTURAL ANALYSIS OF CONDITIONAL PREPARATION IN JUDO
Directory of Open Access Journals (Sweden)
Slavko Obadov
2006-06-01
Full Text Available Conditional preparation is a constituent part of overall sports preparation. Conditional training might be defined as a process of improvement of a sportsman’s functional and motor abilities, morphological characteristics, health, as well as the required motor knowledge. Conditional preparation can be might be classified as: general, basic and situational conditional preparation. Programs of the conditional training might be classified as: developing, resuming, recovering, preventive and recovering ones. High level of the general physical preparation enables maximum demonstration of the physical abilities of a sportsman during the stage of improvement of the specific motor abilities. Good general preparation of a sportsman enables him to push beyond his functional limits in order to cope with heavy loads easier, which subsequently enables him to achieve top performance level. Basic conditional preparation assumes the development of the most important judo abilities. Specific conditional preparation is related directly to the execution of different structural elements under the conditional requirements. Situational conditional preparation enables integration of the tactical and conditional training.
An expert system for integrated structural analysis and design optimization for aerospace structures
1992-04-01
The results of a research study on the development of an expert system for integrated structural analysis and design optimization is presented. An Object Representation Language (ORL) was developed first in conjunction with a rule-based system. This ORL/AI shell was then used to develop expert systems to provide assistance with a variety of structural analysis and design optimization tasks, in conjunction with procedural modules for finite element structural analysis and design optimization. The main goal of the research study was to provide expertise, judgment, and reasoning capabilities in the aerospace structural design process. This will allow engineers performing structural analysis and design, even without extensive experience in the field, to develop error-free, efficient and reliable structural designs very rapidly and cost-effectively. This would not only improve the productivity of design engineers and analysts, but also significantly reduce time to completion of structural design. An extensive literature survey in the field of structural analysis, design optimization, artificial intelligence, and database management systems and their application to the structural design process was first performed. A feasibility study was then performed, and the architecture and the conceptual design for the integrated 'intelligent' structural analysis and design optimization software was then developed. An Object Representation Language (ORL), in conjunction with a rule-based system, was then developed using C++. Such an approach would improve the expressiveness for knowledge representation (especially for structural analysis and design applications), provide ability to build very large and practical expert systems, and provide an efficient way for storing knowledge. Functional specifications for the expert systems were then developed. The ORL/AI shell was then used to develop a variety of modules of expert systems for a variety of modeling, finite element analysis, and
Sediment Analysis Using a Structured Programming Approach
Directory of Open Access Journals (Sweden)
Daniela Arias-Madrid
2012-12-01
Full Text Available This paper presents an algorithm designed for the analysis of a sedimentary sample of unconsolidated material and seeks to identify very quickly the main features that occur in a sediment and thus classify them fast and efficiently. For this purpose, it requires that the weight of each particle size to be entered in the program and using the method of Moments, which is based on four equations representing the mean, standard deviation, skewness and kurtosis, is found the attributes of the sample in few seconds. With the program these calculations are performed in an effective and more accurately way, obtaining also the explanations of the results of the features such as grain size, sorting, symmetry and origin, which helps to improve the study of sediments and in general the study of sedimentary rocks.
Reliability Analysis of Structural Timber Systems
DEFF Research Database (Denmark)
Sørensen, John Dalsgaard; Hoffmeyer, P.
2000-01-01
types of redundancy and non-linearity are considered. The statistical characteristics of the load bearing capacity are determined by reliability analysis. Next, more complex systems are considered modelling the mechanical behaviour of timber roof elements I stressed skin panels made of timber. Using...... characteristics of the load-bearing capacity is estimated in the form of a characteristic value and a coefficient of variation. These two values are of primary importance for codes of practice based on the partial safety factor format since the partial safety factor is closely related to the coefficient...... the above stochastic models, statistical characteristics (distribution function, 5% quantile and coefficient of variation) are determined. Generally, the results show that taking the system effects into account the characteristic load bearing capacity can be increased and the partial safety factor decreased...
Tanker Structural Analysis for Minor Collisions
1975-12-01
masses (including virtual masses of the water), the initial bearings, and velocities. 2. Throughout the analysis, the bow of the striking ship Is...initial velocity of the striking ship: m( F ______ (1 t 0 V20) =0.0 f= virtual mass, ship I 2 = virtual mass, ship 2~ m I V . V f ’ K’ Jt 11 FIUR m-2...situ .K. 5Y( i~ lZAKD bow $H 14ILIQj P Lh5T I C. EQ k Y kps) 0 0 94-1 W~IAk) J~~E 0 oC4O.1 ,I Hi PL~c,1C. tlA% ;OQ)- AULA / ;0) 4 4 4~IN -c Q
Structural model analysis of multiple quantitative traits.
Directory of Open Access Journals (Sweden)
Renhua Li
2006-07-01
Full Text Available We introduce a method for the analysis of multilocus, multitrait genetic data that provides an intuitive and precise characterization of genetic architecture. We show that it is possible to infer the magnitude and direction of causal relationships among multiple correlated phenotypes and illustrate the technique using body composition and bone density data from mouse intercross populations. Using these techniques we are able to distinguish genetic loci that affect adiposity from those that affect overall body size and thus reveal a shortcoming of standardized measures such as body mass index that are widely used in obesity research. The identification of causal networks sheds light on the nature of genetic heterogeneity and pleiotropy in complex genetic systems.
Non-destructive inspection of composite structures using modal analysis
Matthews, Timothy Stirling.
1995-01-01
Anomalies from manufacturing variability or in-service damage are manifested as subtle differences in the inertial and stiffness matrices of otherwise identical components. Modal analysis seeks to model these constitutive relations by examining a structure's dynamic response to applied vibrations. In this investigation, characterization of anomalies in composite structures is attempted through multi-input, multi-output modal analysis. Two graphite-epoxy specimens manufactured by different pro...
Discrete Discriminant analysis based on tree-structured graphical models
DEFF Research Database (Denmark)
Perez de la Cruz, Gonzalo; Eslava, Guillermina
The purpose of this paper is to illustrate the potential use of discriminant analysis based on tree{structured graphical models for discrete variables. This is done by comparing its empirical performance using estimated error rates for real and simulated data. The results show that discriminant...... analysis based on tree{structured graphical models is a simple nonlinear method competitive with, and sometimes superior to, other well{known linear methods like those assuming mutual independence between variables and linear logistic regression....
Understanding the structure of data when planning for analysis ...
African Journals Online (AJOL)
Understanding the structure of data when planning for analysis: application of Hierachical Linear Models. ... South African Journal of Education ... In an educational system, for example, students exist within a hierarchical social structure that can include classroom, grade level, school, school district and country.
A factor analysis of landscape pattern and structure metrics
Kurt H. Riitters; R.V. O' Neill; C.T. Hunsaker; James D. Wickham; D.H. Yankee; S.P. Timmins; K.B. Jones; B.L. Jackson
1995-01-01
Fifty-five metrics of landscape pattern and structure were calculated for 85 maps of land use and land cover. A multivariate factor analysis was used to identify the common axes (or dimensions) of pattern and structure which were measured by a reduced set of 26 metrics. The first six factors explained about 87% of the variation in the 26 landscape metrics. These...
Sensitivity based reduced approaches for structural reliability analysis
Indian Academy of Sciences (India)
captured by a safety-factor based approach due to the intricate nonlinear relationships between the system parameters and the natural frequencies. For these reasons a scientific and systematic approach is required to predict the probability of failure of a structure at the design stage. Probabilistic structural reliability analysis ...
Multiscale analysis of structure development in expanded starch snacks
Sman, van der R.G.M.; Broeze, J.
2014-01-01
In this paper we perform a multiscale analysis of the food structuring process of the expansion of starchy snack foods like keropok, which obtains a solid foam structure. In particular, we want to investigate the validity of the hypothesis of Kokini and coworkers, that expansion is optimal at the
Evidence Regarding the Internal Structure: Confirmatory Factor Analysis
Lewis, Todd F.
2017-01-01
American Educational Research Association (AERA) standards stipulate that researchers show evidence of the internal structure of instruments. Confirmatory factor analysis (CFA) is one structural equation modeling procedure designed to assess construct validity of assessments that has broad applicability for counselors interested in instrument…
Cloning, structural analysis and expression of cardiac troponin C ...
African Journals Online (AJOL)
Yomi
2012-02-23
Feb 23, 2012 ... This study may provide more insight into the molecular structure, expression patterns and evolution of TNNC1 gene in animal. Key words: TroponinC1 gene, molecular cloning, structural analysis, expression, goat. INTRODUCTION ..... relationships of troponin C. Physiological Genomics, 32: 16. Johnson J ...
Accuracy of Dynamic and Acoustic Analysis of Lightweight Panel Structures
DEFF Research Database (Denmark)
Kirkegaard, Poul Henning; Dickow, Kristoffer Ahrens; Andersen, Lars Vabbersgaard
2012-01-01
in such buildings is important. In the lowfrequency range, prediction of sound and vibration in building structures may be achieved by finite-element analysis (FEA). The aim of this paper is to compare the two commercial codes ABAQUS and ANSYS for FEA of an acoustic-structural coupling in a timber lightweight panel...
Hyperfine and magnetic properties of a Y{sub x}La{sub 1−x}FeO{sub 3} series (0 ≤ x ≤ 1)
Energy Technology Data Exchange (ETDEWEB)
Cristóbal, A.A.; Botta, P.M. [Instituto de Investigaciones en Ciencia y Tecnología de Materiales (INTEMA), CONICET-UNMdP, Av. J.B. Justo 4302, B7608FDQ Mar del Plata (Argentina); Bercoff, P.G., E-mail: bercoff@famaf.unc.edu.ar [Facultad de Matemática, Astronomía y Física (FaMAF), Universidad Nacional de Córdoba. IFEG (CONICET), Medina Allende s/n, Ciudad Universitaria, 5000 Córdoba (Argentina); Ramos, C.P. [CONICET and Centro Atómico Constituyentes (CAC), CNEA, Av. Gral. Paz 1499, 1650 San Martín (Argentina)
2015-04-15
Highlights: • Y{sub x}La{sub 1−x}FeO{sub 3} (0 ≤ x ≤ 1) was synthesized by mechanochemistry. • Two magnetic contributions were identified in the series. • A paramagnetic state is associated with a fraction of the smallest particles. • A ferromagnetic state is attributed to the larger particles. • Annealing of samples favored the formation of Y{sub 3}Fe{sub 5}O{sub 12} impurities. - Abstract: A series of orthoferrites Y{sub x}La{sub 1−x}FeO{sub 3} in the entire range of composition was synthesized at room temperature by mechanochemical activation of oxide mixtures. Phase composition, structure and microstructure of the obtained powder materials were characterized by X-ray diffraction and field-emission scanning electron microscopy. Hyperfine interactions and magnetic properties were determined by Mössbauer spectroscopy, SQUID and vibrating sample magnetometry. Two magnetic contributions could be identified in the series of materials: a paramagnetic state, associated with a fraction of the smallest particles and a ferromagnetic state, attributed to the larger particles. The results showed that the relative proportion of both contributions is very dependent on x, the Y content of samples. From M vs T measurements, it was possible to estimate the blocking temperature distribution for the end members of the series. Annealing of samples produced the elimination of the superparamagnetic behavior and the formation of Y{sub 3}Fe{sub 5}O{sub 12} impurities.
Astashkin, Andrei V; Neese, Frank; Raitsimring, Arnold M; Cooney, J Jon A; Bultman, Eric; Enemark, John H
2005-11-30
Ka band ESEEM spectroscopy was used to determine the hyperfine (hfi) and nuclear quadrupole (nqi) interaction parameters for the oxo-17O ligand in [Mo 17O(SPh)4]-, a spectroscopic model of the oxo-Mo(V) centers of enzymes. The isotropic hfi constant of 6.5 MHz found for the oxo-17O is much smaller than the values of approximately 20-40 MHz typical for the 17O nucleus of an equatorial OH(2) ligand in molybdenum enzymes. The 17O nqi parameter (e2qQ/h = 1.45 MHz, eta approximately = 0) is the first to be obtained for an oxo group in a metal complex. The parameters of the oxo-17O ligand, as well as other magnetic resonance parameters of [Mo 17O(SPh)4]- predicted by quasi-relativistic DFT calculations, were in good agreement with those obtained in experiment. From the electronic structure of the complex revealed by DFT, it follows that the SOMO is almost entirely molybdenum d(xy) and sulfur p, while the spin density on the oxo-17O is negative, determined by spin polarization mechanisms. The results of this work will enable direct experimental identification of the oxo ligand in a variety of chemical and biological systems.
Lammer, H.; Carter, R. T.; Huber, J. R.
2000-07-01
Coherent time resolved IR-UV double resonance spectroscopy with REMPI and/or LIF detection has been used to measure the nuclear hyperfine structure of a diatomic and a polyatomic molecule. The pump-probe technique was applied and the experimental set up was optimized to achieve highest spectral resolution. Following excitation of the HCl fundamental vibrational transition by a nanosecond IR laser pulse, the nuclear quadrupole coupling constants were determined to be eQq = -69.51(22) MHz for H35Cl and eQq = -54.40(16) MHz for H37Cl in the J = 1 and J = 2 states of the υ = 1 level. Nuclear (Cl) spin-rotation interaction was shown to be active with the corresponding coupling constant being C I = 0.068(10) MHz for H35Cl and C I = 0.049(8) MHz for H37Cl. For pyrimidine a C-H stretch vibration ν 13 was excited and the quadrupole tensor elements for the rovibronic states J K a , K c = 110 and 101 of the υ 13 = 1 level were found to be χ aa = -3.095(10) MHz, χ bb = 0.227(10) MHz and χ cc = 3.322(10) MHz. In this case the residual frequency error was reduced to 8 kHz. The results of these jet experiments independently confirm those from millimeter wave and microwave measurements on static gas samples.
A method for rapid similarity analysis of RNA secondary structures
Directory of Open Access Journals (Sweden)
Liu Na
2006-11-01
Full Text Available Abstract Background Owing to the rapid expansion of RNA structure databases in recent years, efficient methods for structure comparison are in demand for function prediction and evolutionary analysis. Usually, the similarity of RNA secondary structures is evaluated based on tree models and dynamic programming algorithms. We present here a new method for the similarity analysis of RNA secondary structures. Results Three sets of real data have been used as input for the example applications. Set I includes the structures from 5S rRNAs. Set II includes the secondary structures from RNase P and RNase MRP. Set III includes the structures from 16S rRNAs. Reasonable phylogenetic trees are derived for these three sets of data by using our method. Moreover, our program runs faster as compared to some existing ones. Conclusion The famous Lempel-Ziv algorithm can efficiently extract the information on repeated patterns encoded in RNA secondary structures and makes our method an alternative to analyze the similarity of RNA secondary structures. This method will also be useful to researchers who are interested in evolutionary analysis.
Directory of Open Access Journals (Sweden)
Pan Dan-guang
2015-01-01
Full Text Available For realizing the variation of structural dynamic characteristics due to neighbor structure in buildings group, the surface structure is idealized as an equivalent single degree of freedom system with rigid base whose site consists of a single homogeneous layer. Based on the model, a equivalent method on the equivalent seismic excitation is proposed. Then, the differences of seismic response and equivalent seismic input between soil - structure interaction (SSI system and structure -soil-structure interaction (SSSI system are investigated by harmonic analysis. The numerical results show that dynamic responses would be underestimated in SSSI system when the forcing frequencies are close to the Natural frequency if the effects of neighborhood structure were ignored. Neighborhood structure would make the translational displacement increase and rocking vibration decrease. When establishing an effective seismic input, it is necessary to consider the impact of inertia interaction.
Advanced analysis and design for fire safety of steel structures
Li, Guoqiang
2013-01-01
Advanced Analysis and Design for Fire Safety of Steel Structures systematically presents the latest findings on behaviours of steel structural components in a fire, such as the catenary actions of restrained steel beams, the design methods for restrained steel columns, and the membrane actions of concrete floor slabs with steel decks. Using a systematic description of structural fire safety engineering principles, the authors illustrate the important difference between behaviours of an isolated structural element and the restrained component in a complete structure under fire conditions. The book will be an essential resource for structural engineers who wish to improve their understanding of steel buildings exposed to fires. It is also an ideal textbook for introductory courses in fire safety for master’s degree programs in structural engineering, and is excellent reading material for final-year undergraduate students in civil engineering and fire safety engineering. Furthermore, it successfully bridges th...
Structural analysis of cell wall polysaccharides using PACE
Energy Technology Data Exchange (ETDEWEB)
Mortimer, Jennifer C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint BioEnergy Institute
2017-01-01
The plant cell wall is composed of many complex polysaccharides. The composition and structure of the polysaccharides affect various cell properties including cell shape, cell function and cell adhesion. Many techniques to characterize polysaccharide structure are complicated, requiring expensive equipment and specialized operators e.g. NMR, MALDI-MS. PACE (Polysaccharide Analysis using Carbohydrate gel Electrophoresis) uses a simple, rapid technique to analyze polysaccharide quantity and structure (Goubet et al. 2002). Whilst the method here describes xylan analysis, it can be applied (by use of the appropriate glycosyl hydrolase) to any cell wall polysaccharide.
Structural mode significance using INCA. [Interactive Controls Analysis computer program
Bauer, Frank H.; Downing, John P.; Thorpe, Christopher J.
1990-01-01
Structural finite element models are often too large to be used in the design and analysis of control systems. Model reduction techniques must be applied to reduce the structural model to manageable size. In the past, engineers either performed the model order reduction by hand or used distinct computer programs to retrieve the data, to perform the significance analysis and to reduce the order of the model. To expedite this process, the latest version of INCA has been expanded to include an interactive graphical structural mode significance and model order reduction capability.
Course transformation: Content, structure and effectiveness analysis
DuHadway, Linda P.
The organization of learning materials is often limited by the systems available for delivery of such material. Currently, the learning management system (LMS) is widely used to distribute course materials. These systems deliver the material in a text-based, linear way. As online education continues to expand and educators seek to increase their effectiveness by adding more effective active learning strategies, these delivery methods become a limitation. This work demonstrates the possibility of presenting course materials in a graphical way that expresses important relations and provides support for manipulating the order of those materials. The ENABLE system gathers data from an existing course, uses text analysis techniques, graph theory, graph transformation, and a user interface to create and present graphical course maps. These course maps are able to express information not currently available in the LMS. Student agents have been developed to traverse these course maps to identify the variety of possible paths through the material. The temporal relations imposed by the current course delivery methods have been replaced by prerequisite relations that express ordering that provides educational value. Reducing the connections to these more meaningful relations allows more possibilities for change. Technical methods are used to explore and calibrate linear and nonlinear models of learning. These methods are used to track mastery of learning material and identify relative difficulty values. Several probability models are developed and used to demonstrate that data from existing, temporally based courses can be used to make predictions about student success in courses using the same material but organized without the temporal limitations. Combined, these demonstrate the possibility of tools and techniques that can support the implementation of a graphical course map that allows varied paths and provides an enriched, more informative interface between the educator
Impact of silica environment on hyperfine interactions in ε-Fe{sub 2}O{sub 3} nanoparticles
Energy Technology Data Exchange (ETDEWEB)
Kubíčková, Lenka, E-mail: sagittaria.64@gmail.com; Kohout, Jaroslav [Charles University in Prague, Faculty of Mathematics and Physics (Czech Republic); Brázda, Petr; Veverka, Miroslav [Institute of Physics of the AS CR, v.v.i. (Czech Republic); Kmječ, Tomáš; Kubániová, Denisa [Charles University in Prague, Faculty of Mathematics and Physics (Czech Republic); Bezdička, Petr [Institute of Inorganic Chemistry of the AS CR, v.v.i. (Czech Republic); Klementová, Mariana; Šantavá, Eva [Institute of Physics of the AS CR, v.v.i. (Czech Republic); Závěta, Karel [Charles University in Prague, Faculty of Mathematics and Physics (Czech Republic)
2016-12-15
Magnetic nanoparticles have found broad applications in medicine, especially for cell targeting and transport, and as contrast agents in MRI. Our samples of ε-Fe{sub 2}O{sub 3} nanoparticles were prepared by annealing in silica matrix, which was leached off and the bare particles were then coated with amorphous silica layers of various thicknesses. The distribution of particle sizes was determined from the TEM pictures giving the average size ∼20 nm and the thickness of silica coating ∼5; 8; 12; 19 nm. The particles were further characterized by the XRPD and DC magnetic measurements. The nanoparticles consisted mainly of ε-Fe{sub 2}O{sub 3} with admixtures of ∼1 % of the α phase and less than 1 % of the γ phase. The hysteresis loops displayed coercivities of ∼2 T at room temperature. The parameters of hyperfine interactions were derived from transmission Mössbauer spectra. Observed differences of hyperfine fields for nanoparticles in the matrix and the bare ones are ascribed to strains produced during cooling of the composite. This interpretation is supported by slight changes of their lattice parameters and increase of the elementary cell volume deduced from XRD. The temperature dependence of the magnetization indicated a two-step magnetic transition of the ε-Fe{sub 2}O{sub 3} nanoparticles spread between ∼85 K and ∼150 K, which is slightly modified by remanent tensile stresses in the case of nanoparticles in the matrix. The subsequent coating of the bare particles by silica produced no further change in hyperfine parameters, which indicates that this procedure does not modify magnetic properties of nanoparticles.
2-D Finite Element Analysis of Massive RC Structures
DEFF Research Database (Denmark)
Saabye Ottosen, Niels
1982-01-01
Nonlinear analysis of concrete structures using finite elements is discussed. The applications include a thick-walled top-closure for a pressure vessel as well as the delicate problems of beams failing in shear. The top-closure analysis evaluates the effect of two different failure criteria...
Structure Learning by Pruning in Independent Component Analysis
DEFF Research Database (Denmark)
Kjems, Andreas; Hansen, Lars Kai
2006-01-01
We discuss pruning as a means of structure learning in independent component analysis. Sparse models are attractive in both signal processing and in analysis of abstract data, they can assist model interpretation, generalizability and reduce computation. We derive the relevant saliency expressions...
Formula for Forced Vibration Analysis of Structures Using Static ...
African Journals Online (AJOL)
This Paper proposed and examined a formula for forced vibration analysis of structures using static factored response as equivalent dynamic response. Some methods of dynamic analysis are based on using static factored response as equivalent dynamic response thereby excluding the formulation of the equations of ...
Structural analysis for diagnosis with application to ship propulsion problem
DEFF Research Database (Denmark)
Izadi-Zamanabadi, Roozbeh; Blanke, Mogens
2002-01-01
Aiming at design of algorithms for fault diagnosis, structural analysis of systems offers concise yet easy overall analysis. Graph-based matching, which is the essential tech-nique to obtain redundant information for diagnosis, is reconsidered in this paper. Matching is reformulated as a problem...
Structural Analysis for Diagnosis - the Matching Problem Revisited
DEFF Research Database (Denmark)
Izadi-Zamanabadi, Roozbeh; Blanke, Mogens
2002-01-01
Aiming at design of algorithms for fault diagnosis, structural analysis of systems offers concise yet easy overall analysis. Graph-based matching, which is the essential technique to obtain redundant information for diagnosis, is re-considered in this paper. Matching is re-formulated as a problem...
Structural Task Analysis--The Bridge Between Selection and Training.
Dees, James W.
A procedure for using Guilford's structure of the intellect as the theoretical basis for a task analysis model is presented. It is reasoned that such a model would furnish a bridge between task analysis and test selection, and also a bridge between test selection and test validation. Such a mechanism might answer some fo the EEOC criticisms of…
Tempered Water Lower Port Connector Structural Analysis Verification
Energy Technology Data Exchange (ETDEWEB)
CREA, B.A.
2000-05-05
Structural analysis of the lower port connection of the Tempered Water System of the Cold Vacuum Drying Facility was performed. Subsequent detailed design changes to enhance operability resulted in the need to re-evaluate the bases of the original analysis to verify its continued validity. This evaluation is contained in Appendix A of this report. The original evaluation is contained in Appendix B.
Power flow analysis of an L-shaped plate structure
Cuschieri, J. M.
1987-01-01
In the analysis of the vibration response and structure-borne vibration transmission between elements of a complex structure, statistical energy analysis (SEA) or finite element analysis (FEA) are generally used. However, an alternative method is using vibrational power flow techniques which can be especially useful in the mid frequencies between the optimum frequency regimes for FEA and SEA. Power flow analysis has in general been used on one-dimensional beam-like structures or between structures with point joints. In this paper, the power flow technique is extended to two-dimensional plate like structures joined along a common edge without frequency or spatial averaging the results, such that the resonant response of the structure is determined. The power flow results are compared to results obtained using FEA at low frequencies and SEA at high frequencies. The agreement with FEA results is good but the power flow technique has an improved computational efficiency. Compared to the SEA results the power flow results show a closer representation of the actual response of the structure.
Population structure analysis using rare and common functional variants
Directory of Open Access Journals (Sweden)
Ding Lili
2011-11-01
Full Text Available Abstract Next-generation sequencing technologies now make it possible to genotype and measure hundreds of thousands of rare genetic variations in individuals across the genome. Characterization of high-density genetic variation facilitates control of population genetic structure on a finer scale before large-scale genotyping in disease genetics studies. Population structure is a well-known, prevalent, and important factor in common variant genetic studies, but its relevance in rare variants is unclear. We perform an extensive population structure analysis using common and rare functional variants from the Genetic Analysis Workshop 17 mini-exome sequence. The analysis based on common functional variants required 388 principal components to account for 90% of the variation in population structure. However, an analysis based on rare variants required 532 significant principal components to account for similar levels of variation. Using rare variants, we detected fine-scale substructure beyond the population structure identified using common functional variants. Our results show that the level of population structure embedded in rare variant data is different from the level embedded in common variant data and that correcting for population structure is only as good as the level one wishes to correct.
Fluid-structure coupled analysis of underwater cylindrical shells
Ai, Shang-Mao; Sun, Li-Ping
2008-06-01
Underwater cylindrical shell structures have been found a wide of application in many engineering fields, such as the element of marine, oil platforms, etc. The coupled vibration analysis is a hot issue for these underwater structures. The vibration characteristics of underwater structures are influenced not only by hydrodynamic pressure but also by hydrostatic pressure corresponding to different water depths. In this study, an acoustic finite element method was used to evaluate the underwater structures. Taken the hydrostatic pressure into account in terms of initial stress stiffness, an acoustical fluid-structure coupled analysis of underwater cylindrical shells has been made to study the effect of hydrodynamic pressures on natural frequency and sound radiation. By comparing with the frequencies obtained by the acoustic finite element method and by the added mass method based on the Bessel function, the validity of present analysis was checked. Finally, test samples of the sound radiation of stiffened cylindrical shells were acquired by a harmonic acoustic analysis. The results showed that hydrostatic pressure plays an important role in determining a large submerged body motion, and the characteristics of sound radiation change with water depth. Furthermore, the analysis methods and the results are of significant reference value for studies of other complicated submarine structures.
Structure optimization and simulation analysis of the quartz micromachined gyroscope
Directory of Open Access Journals (Sweden)
Xuezhong Wu
2014-02-01
Full Text Available Structure optimization and simulation analysis of the quartz micromachined gyroscope are reported in this paper. The relationships between the structure parameters and the frequencies of work mode were analysed by finite element analysis. The structure parameters of the quartz micromachined gyroscope were optimized to reduce the difference between the frequencies of the drive mode and the sense mode. The simulation results were proved by testing the prototype gyroscope, which was fabricated by micro-electromechanical systems (MEMS technology. Therefore, the frequencies of the drive mode and the sense mode can match each other by the structure optimization and simulation analysis of the quartz micromachined gyroscope, which is helpful in the design of the high sensitivity quartz micromachined gyroscope.
Structural Reliability Analysis Using Orthogonalizable Power Polynomial Basis Vector
Directory of Open Access Journals (Sweden)
Li Yejun
2017-01-01
Full Text Available A new method for structural reliability analysis using orthogonalizable power polynomial basis vector is presented. Firstly, a power polynomial basis vector is adopted to express the initial series solution of structural response, which is determined by a series of deterministic recursive equation based on perturbation technique, and then transferred to be a set of orthogonalizable power polynomial basis vector using the orthogonalization technique. By conducting Garlekin projection, an accelerating factor vector of the orthogonalizable power polynomial expansion is determined by solving small scale algebraic equations. Numerical results of a continuous bridge structure on reliability analysis shows that the proposed method can achieve the accuracy of the Direct Monte Carlo method and can save a lot of computation time at the same time, it is both accurate and efficient, and is very competitive to be used in structural reliability analysis.
Rapid structural analysis of nanomaterials in aqueous solutions
Ryuzaki, Sou; Tsutsui, Makusu; He, Yuhui; Yokota, Kazumichi; Arima, Akihide; Morikawa, Takanori; Taniguchi, Masateru; Kawai, Tomoji
2017-04-01
Rapid structural analysis of nanoscale matter in a liquid environment represents innovative technologies that reveal the identities and functions of biologically important molecules. However, there is currently no method with high spatio-temporal resolution that can scan individual particles in solutions to gain structural information. Here we report the development of a nanopore platform realizing quantitative structural analysis for suspended nanomaterials in solutions with a high z-axis and xy-plane spatial resolution of 35.8 ± 1.1 and 12 nm, respectively. We used a low thickness-to-diameter aspect ratio pore architecture for achieving cross sectional areas of analyte (i.e. tomograms). Combining this with multiphysics simulation methods to translate ionic current data into tomograms, we demonstrated rapid structural analysis of single polystyrene (Pst) beads and single dumbbell-like Pst beads in aqueous solutions.
Parallel-vector algorithms for analysis of large structures
Soegiarso, R.; Adeli, H.
1995-01-01
In analysis of large space structures, the major computational steps are evaluation and assembly of the structure stiffness matrix and solution of the resulting simultaneous linear equations. In this paper we present efficient parallel-vector algorithms for these steps of structural analysis. The goal is to optimize the performance of the algorithms through judicious combination of parallel processing and vectorization. Parallel-vector algorithms are presented for solution of linear simultaneous equations using Cholesky decomposition and preconditioned conjugate gradient approaches. The algorithms are applied to three large space structures modeling the exterior envelope of high-rise and super high-rise building structures in the range of 50-162 stories with up to 6,136 members. Performance results are presented in terms of central-processing-unit time on a Cray Y-MP8/864 supercomputer, MFLOPS (millions of floating point operations per second), and speedup.
Engineering and Design: Nonlinear, Incremental Structural Analysis of Massive Concrete Structures
1994-08-31
This engineer technical letter (ETL) provides guidance for performing a nonlinear, incremental structural analysis (NISA) for massive concrete ... structures (MCS). This ETL applies to HQUSACE elements, major subordinate commands, districts, laboratories, and field operating activities (FOA) having responsibilities for the design of civil works projects.
A discourse on sensitivity analysis for discretely-modeled structures
Adelman, Howard M.; Haftka, Raphael T.
1991-01-01
A descriptive review is presented of the most recent methods for performing sensitivity analysis of the structural behavior of discretely-modeled systems. The methods are generally but not exclusively aimed at finite element modeled structures. Topics included are: selections of finite difference step sizes; special consideration for finite difference sensitivity of iteratively-solved response problems; first and second derivatives of static structural response; sensitivity of stresses; nonlinear static response sensitivity; eigenvalue and eigenvector sensitivities for both distinct and repeated eigenvalues; and sensitivity of transient response for both linear and nonlinear structural response.
Ambient Response Analysis Modal Analysis for Large Structures
DEFF Research Database (Denmark)
Brincker, Rune; Andersen, Palle
1999-01-01
In this paper an outline is given of the basic ideas in ambient respons analysis, i.e. when modal analyses is performed on systems based on output only. Some of the most known techniques are briefly introduced, and the basic problems discussed. The introduced techniques are the frequency domain...... based peak-picking methods, the polyreference LSCE method, the stochastic subspace method for estimation of state space systems and the prediction error method for estimation of Auto-Regressive Moving Average Vector models. The techniques are illustrated on an example of ambient response measurments...
Numerical Analysis of Vibrations of Structures under Moving Inertial Load
Bajer, Czeslaw I
2012-01-01
Moving inertial loads are applied to structures in civil engineering, robotics, and mechanical engineering. Some fundamental books exist, as well as thousands of research papers. Well known is the book by L. Frýba, Vibrations of Solids and Structures Under Moving Loads, which describes almost all problems concerning non-inertial loads. This book presents broad description of numerical tools successfully applied to structural dynamic analysis. Physically we deal with non-conservative systems. The discrete approach formulated with the use of the classical finite element method results in elemental matrices, which can be directly added to global structure matrices. A more general approach is carried out with the space-time finite element method. In such a case, a trajectory of the moving concentrated parameter in space and time can be simply defined. We consider structures described by pure hyperbolic differential equations such as strings and structures described by hyperbolic-parabolic differential equations ...
Ricles, James M.
1990-01-01
The development and preliminary assessment of a method for dynamic structural analysis based on load-dependent Ritz vectors are presented. The vector basis is orthogonalized with respect to the mass and structural stiffness in order that the equations of motion can be uncoupled and efficient analysis of large space structure performed. A series of computer programs was developed based on the algorithm for generating the orthogonal load-dependent Ritz vectors. Transient dynamic analysis performed on the Space Station Freedom using the software was found to provide solutions that require a smaller number of vectors than the modal analysis method. Error norm based on the participation of the mass distribution of the structure and spatial distribution of structural loading, respectively, were developed in order to provide an indication of vector truncation. These norms are computed before the transient analysis is performed. An assessment of these norms through a convergence study of the structural response was performed. The results from this assessment indicate that the error norms can provide a means of judging the quality of the vector basis and accuracy of the transient dynamic solution.
Analysis on the structure of the TMT's Atmospheric Dispersion Corrector
Zhang, Jianhuan; Liu, Yan; Tao, Jin
2015-10-01
The concepts of atmospheric refraction and atmospheric dispersion are introduced and the method of how to eliminate atmospheric dispersion. This article introduces the structure of Atmospheric Dispersion Correction , the installation position of ADC in TMT telescope and the introduction to the principle of ADC in detail. Using the finite element analysis software Ansys Workbench to analyze the rationality of the ADC structure. Static analysis The ADC structure is loaded with two tape lens, which is more 400kg in weight, as well as itself weight, will deform in x, y, z directions. Dynamic analysis The dynamic performances of ADC structure are very important for the construction of the instrument, for the environmental vibration need to be tested. That is the effect of ADC dynamic deformation on optical accuracy is crucial for imaging quality. Here three order modes of dynamic performance are presented for the references of ADC design. They are 1st order mode , 2nd order mode and 3rd order mode. Thermal deformation according to the ADC working environment temperature change, the instrument temperature would be from -5 to 9 degree. So the thermal deformation of ADC is performed in this temperature fluctuation. ADC structure FEA conclusions: The ADC tapered lens are assumed as a rigid body and the mechanical analysis results are: Static analysis, Kinetics analysis and Thermodynamic analysis. Based on the FEA results, we get the image motion information in the telescope plane. Then, we draw a conclusion that: image motions induced by current structure design are very small and meet the requirements of ADC.
Thermal analysis of two-dimensional structures in fire
Directory of Open Access Journals (Sweden)
I. Pierin
Full Text Available The structural materials, as reinforced concrete, steel, wood and aluminum, when heated have their mechanical proprieties degraded. In fire, the structures are subject to elevated temperatures and consequently the load capacity of the structural elements is reduced. The Brazilian and European standards show the minimal dimensions for the structural elements had an adequate bearing capacity in fire. However, several structural checks are not contemplated in methods provided by the standards. In these situations, the knowledge of the temperature distributions inside of structural elements as function of time of exposition is required. The aim of this paper is present software developed by the authors called ATERM. The software performs the thermal transient analysis of two-dimensional structures. The structure may be formed of any material and heating is provided by means of a curve of temperature versus time. The data input and the visualization of the results is performed thought the GiD software. Several examples are compared with software Super TempCalc and ANSYS. Some conclusions and recommendations about the thermal analysis are presented
Spatial Analysis of Linear Structures in the Exploration of Groundwater
Directory of Open Access Journals (Sweden)
Abdramane Dembele
2017-11-01
Full Text Available The analysis of linear structures on major geological formations plays a crucial role in resource exploration in the Inner Niger Delta. Highlighting and mapping of the large lithological units were carried out using image fusion, spectral bands (RGB coding, Principal Component Analysis (PCA, and band ratio methods. The automatic extraction method of linear structures has permitted the obtaining of a structural map with 82,659 linear structures, distributed on different stratigraphic stages. The intensity study shows an accentuation in density over 12.52% of the total area, containing 22.02% of the linear structures. The density and nodes (intersections of fractures formed by the linear structures on the different lithologies allowed to observe the behavior of the region’s aquifers in the exploration of subsoil resources. The central density, in relation to the hydrographic network of the lowlands, shows the conditioning of the flow and retention of groundwater in the region, and in-depth fluids. The node areas and high-density linear structures, have shown an ability to have rejections in deep (pores that favor the formation of structural traps for oil resources.
Finite element thermal analysis of convectively-cooled aircraft structures
Wieting, A. R.; Thornton, E. A.
1981-01-01
The design complexity and size of convectively-cooled engine and airframe structures for hypersonic transports necessitate the use of large general purpose computer programs for both thermal and structural analyses. Generally thermal analyses are based on the lumped-parameter finite difference technique, and structural analyses are based on the finite element technique. Differences in these techniques make it difficult to achieve an efficient interface. It appears, therefore, desirable to conduct an integrated analysis based on a common technique. A summary is provided of efforts by NASA concerned with the development of an integrated thermal structural analysis capability using the finite element method. Particular attention is given to the development of conduction/forced-convection finite element methodology and applications which illustrate the capabilities of the developed concepts.
A Morphogenetic Design Approach with Embedded Structural Analysis
DEFF Research Database (Denmark)
Jensen, Mads Brath; Kirkegaard, Poul Henning; Holst, Malene Kirstine
2010-01-01
The present paper explores a morphogenetic design approach with embedded structural analysis for architectural design. A material system based on a combined space truss and membrane system has been derived as a growth system with inspiration from natural growth of plants. The structural system...... is capable of adding new elements based on a structural analysis of the existing components and their internal stress levels. A GA decision-making procedure that control the generation of the growth cycles is introduced. This evaluation and generation loop is capable of successfully making decisions based...... on several, and often conflicting, inputs formulated from architectural requirements. An experiment with a tri-pyramid component has been considered, but many other space truss systems could be explored in the same manner and result in highly performative outcomes. not only with respect to the structural...
Hyperfine interactions in dilute Se doped Fe{sub x}Sb{sub 1−x} bulk alloy
Energy Technology Data Exchange (ETDEWEB)
Sarkar, Mitesh, E-mail: miteshsarkar-msu@yahoo.com; Agrawal, Naveen [The M. S. University of Baroda, Department of Physics (India); Chawda, Mukesh [Polytechnic, The M. S. University of Baroda, Department of Applied Physics (India)
2016-12-15
Hyperfine Interaction technique like Moessbauer spectroscopy is a very sensitive tool to study the local probe interactions in Iron doped alloys and compounds. We report here the Moessbauer study of the effect of Fe concentration variations in dilute magnetic semiconducting Se{sub 0.004}Fe{sub x}Sb{sub 1−x} alloys for x = 0.002, 0.004 and 0.008. The materials were characterized using X-ray diffraction technique (XRD), Fourier Transform Infra-red spectroscopy (FTIR), Neutron depolarization and Moessbauer spectroscopy. The FTIR result shows the semiconducting behavior of the alloys with band gap of 0.18 eV. From Moessbauer spectroscopy two magnetic sites (A and B) were observed. The value of hyperfine magnetic fields (HMF) of ∼ 308 kOe (site A) and 270 kOe (site B) was constant with increase in Fe concentration. A nonmagnetic interaction was also observed with quadrupole splitting (QS) of 1.26 mm/sec (site C) for x = 0.004 and x = 0.008. The Neutron depolarization studies indicate that the clusters of Fe or Fe based compounds having net magnetic moments with a size greater than 100 Å is absent.
Frequency tripled 1542 nm telecom laser diode stabilized to iodine hyperfine line in the 10-15 range
Philippe, Charles; Holleville, David; Lours, Michel; Minh-Pham, Tuam; Hrabina, Jan; Burck, Frederic Du; Wolf, Peter; Acef, Ouali
2016-01-01
We report on telecom laser frequency stabilization to narrow iodine hyperfine line in the green range of the optical domain, after a frequency tripling process using two nonlinear PPLN crystals. We have generated up to 300 mW optical power in the green (P3w), from 800 mW of infrared power (Pw). This result corresponds to an optical conversion efficiency eta= P3w/Pw ~ 36 %. To our knowledge, this is the best value ever demonstrated for a CW frequency tripling process. We have used a narrow linewidth iodine hyperfine line (component a1 of the 127I2 R 35 (44-0) line) to stabilize the IR laser yielding to frequency stability of 4.8x10-14 t-1/2 with a minimum of 6x10-15 reached after 50 s of integration time. The whole optical setup is very compact and mostly optically fibered. This approach opens the way for efficient and elegant architecture development for space applications as one of several potential uses.
COMPARISON OF METHODS USED FOR SEISMIC ANALYSIS OF STRUCTURES
Directory of Open Access Journals (Sweden)
Petr Čada
2017-11-01
Full Text Available This paper investigates effects of the seismic load to a structure. The article describes main methods of the definition and practical application of the seismic load based on the Standard Eurocode 8. There was made a comparison of all methods using the same structure. A simple two-storeyed concrete 2D-frame with fixed joints was chosen. A one another model with rigid beams for some calculations was defined. The second model can be used for hand-calculations as a cantilever with two masses. The paper describes main dynamic properties of the chosen structure. Seismic load was defined by lateral force method, modal response spectrum, non-linear time-history analysis and pushover analysis. The time-history analysis is represented by accelerograms. There were made linear and non-linear calculations.
Directory of Open Access Journals (Sweden)
Heiland Randy
2006-03-01
Full Text Available Abstract Background Understanding protein function from its structure is a challenging problem. Sequence based approaches for finding homology have broad use for annotation of both structure and function. 3D structural information of protein domains and their interactions provide a complementary view to structure function relationships to sequence information. We have developed a web site http://www.sblest.org/ and an API of web services that enables users to submit protein structures and identify statistically significant neighbors and the underlying structural environments that make that match using a suite of sequence and structure analysis tools. To do this, we have integrated S-BLEST, PSI-BLAST and HMMer based superfamily predictions to give a unique integrated view to prediction of SCOP superfamilies, EC number, and GO term, as well as identification of the protein structural environments that are associated with that prediction. Additionally, we have extended UCSF Chimera and PyMOL to support our web services, so that users can characterize their own proteins of interest. Results Users are able to submit their own queries or use a structure already in the PDB. Currently the databases that a user can query include the popular structural datasets ASTRAL 40 v1.69, ASTRAL 95 v1.69, CLUSTER50, CLUSTER70 and CLUSTER90 and PDBSELECT25. The results can be downloaded directly from the site and include function prediction, analysis of the most conserved environments and automated annotation of query proteins. These results reflect both the hits found with PSI-BLAST, HMMer and with S-BLEST. We have evaluated how well annotation transfer can be performed on SCOP ID's, Gene Ontology (GO ID's and EC Numbers. The method is very efficient and totally automated, generally taking around fifteen minutes for a 400 residue protein. Conclusion With structural genomics initiatives determining structures with little, if any, functional characterization
Peters, Brandon; Moad, Charles; Youn, Eunseog; Buffington, Kris; Heiland, Randy; Mooney, Sean
2006-03-09
Understanding protein function from its structure is a challenging problem. Sequence based approaches for finding homology have broad use for annotation of both structure and function. 3D structural information of protein domains and their interactions provide a complementary view to structure function relationships to sequence information. We have developed a web site http://www.sblest.org/ and an API of web services that enables users to submit protein structures and identify statistically significant neighbors and the underlying structural environments that make that match using a suite of sequence and structure analysis tools. To do this, we have integrated S-BLEST, PSI-BLAST and HMMer based superfamily predictions to give a unique integrated view to prediction of SCOP superfamilies, EC number, and GO term, as well as identification of the protein structural environments that are associated with that prediction. Additionally, we have extended UCSF Chimera and PyMOL to support our web services, so that users can characterize their own proteins of interest. Users are able to submit their own queries or use a structure already in the PDB. Currently the databases that a user can query include the popular structural datasets ASTRAL 40 v1.69, ASTRAL 95 v1.69, CLUSTER50, CLUSTER70 and CLUSTER90 and PDBSELECT25. The results can be downloaded directly from the site and include function prediction, analysis of the most conserved environments and automated annotation of query proteins. These results reflect both the hits found with PSI-BLAST, HMMer and with S-BLEST. We have evaluated how well annotation transfer can be performed on SCOP ID's, Gene Ontology (GO) ID's and EC Numbers. The method is very efficient and totally automated, generally taking around fifteen minutes for a 400 residue protein. With structural genomics initiatives determining structures with little, if any, functional characterization, development of protein structure and function analysis tools are a
Structural Reliability Analysis Using Orthogonalizable Power Polynomial Basis Vector
Li Yejun; Huang Bin
2017-01-01
A new method for structural reliability analysis using orthogonalizable power polynomial basis vector is presented. Firstly, a power polynomial basis vector is adopted to express the initial series solution of structural response, which is determined by a series of deterministic recursive equation based on perturbation technique, and then transferred to be a set of orthogonalizable power polynomial basis vector using the orthogonalization technique. By conducting Garlekin projection, an accel...
Better Finite-Element Analysis of Composite Shell Structures
Clarke, Gregory
2007-01-01
A computer program implements a finite-element-based method of predicting the deformations of thin aerospace structures made of isotropic materials or anisotropic fiber-reinforced composite materials. The technique and corresponding software are applicable to thin shell structures in general and are particularly useful for analysis of thin beamlike members having open cross-sections (e.g. I-beams and C-channels) in which significant warping can occur.
Tools for integrated sequence-structure analysis with UCSF Chimera
Directory of Open Access Journals (Sweden)
Huang Conrad C
2006-07-01
Full Text Available Abstract Background Comparing related structures and viewing the structures in the context of sequence alignments are important tasks in protein structure-function research. While many programs exist for individual aspects of such work, there is a need for interactive visualization tools that: (a provide a deep integration of sequence and structure, far beyond mapping where a sequence region falls in the structure and vice versa; (b facilitate changing data of one type based on the other (for example, using only sequence-conserved residues to match structures, or adjusting a sequence alignment based on spatial fit; (c can be used with a researcher's own data, including arbitrary sequence alignments and annotations, closely or distantly related sets of proteins, etc.; and (d interoperate with each other and with a full complement of molecular graphics features. We describe enhancements to UCSF Chimera to achieve these goals. Results The molecular graphics program UCSF Chimera includes a suite of tools for interactive analyses of sequences and structures. Structures automatically associate with sequences in imported alignments, allowing many kinds of crosstalk. A novel method is provided to superimpose structures in the absence of a pre-existing sequence alignment. The method uses both sequence and secondary structure, and can match even structures with very low sequence identity. Another tool constructs structure-based sequence alignments from superpositions of two or more proteins. Chimera is designed to be extensible, and mechanisms for incorporating user-specific data without Chimera code development are also provided. Conclusion The tools described here apply to many problems involving comparison and analysis of protein structures and their sequences. Chimera includes complete documentation and is intended for use by a wide range of scientists, not just those in the computational disciplines. UCSF Chimera is free for non-commercial use and is
Tools for integrated sequence-structure analysis with UCSF Chimera.
Meng, Elaine C; Pettersen, Eric F; Couch, Gregory S; Huang, Conrad C; Ferrin, Thomas E
2006-07-12
Comparing related structures and viewing the structures in the context of sequence alignments are important tasks in protein structure-function research. While many programs exist for individual aspects of such work, there is a need for interactive visualization tools that: (a) provide a deep integration of sequence and structure, far beyond mapping where a sequence region falls in the structure and vice versa; (b) facilitate changing data of one type based on the other (for example, using only sequence-conserved residues to match structures, or adjusting a sequence alignment based on spatial fit); (c) can be used with a researcher's own data, including arbitrary sequence alignments and annotations, closely or distantly related sets of proteins, etc.; and (d) interoperate with each other and with a full complement of molecular graphics features. We describe enhancements to UCSF Chimera to achieve these goals. The molecular graphics program UCSF Chimera includes a suite of tools for interactive analyses of sequences and structures. Structures automatically associate with sequences in imported alignments, allowing many kinds of crosstalk. A novel method is provided to superimpose structures in the absence of a pre-existing sequence alignment. The method uses both sequence and secondary structure, and can match even structures with very low sequence identity. Another tool constructs structure-based sequence alignments from superpositions of two or more proteins. Chimera is designed to be extensible, and mechanisms for incorporating user-specific data without Chimera code development are also provided. The tools described here apply to many problems involving comparison and analysis of protein structures and their sequences. Chimera includes complete documentation and is intended for use by a wide range of scientists, not just those in the computational disciplines. UCSF Chimera is free for non-commercial use and is available for Microsoft Windows, Apple Mac OS X
Energy Technology Data Exchange (ETDEWEB)
Yamazaki, Takayuki, E-mail: yamazaki@icepp.s.u-tokyo.ac.jp; Miyazaki, Akira; Suehara, Taikan; Namba, Toshio; Asai, Shoji; Kobayashi, Tomio [University of Tokyo, Department of Physics, Graduate School of Science, and International Center for Elementary Particle Physics (Japan); Saito, Haruo [University of Tokyo, Graduate School of Arts and Sciences (Japan); Urushizaki, Yuichi; Ogawa, Isamu; Idehara, Toshitaka [University of Fukui, Research Center for Development of Far-Infrared Region (Japan); Sabchevski, Svilen [Bulgarian Academy of Sciences (Bulgaria)
2012-12-15
Positronium is an ideal system for the research of the bound state QED. The hyperfine splitting of positronium (Ps-HFS, about 203 GHz) is an important observable but all previous measurements of Ps-HFS had been measured indirectly using Zeeman splitting. There might be the unknown systematic errors on the uniformity of magnetic field. We are trying to measure Ps-HFS directly using sub-THz radiation. We developed an optical system to accumulate high power (about 10 kW) radiation in a Fabry-Perot resonant cavity and observed the positronium hyperfine transition for the first time.
Finite element analysis of structures through unified formulation
Carrera, Erasmo; Petrolo, Marco; Zappino, Enrico
2014-01-01
The finite element method (FEM) is a computational tool widely used to design and analyse complex structures. Currently, there are a number of different approaches to analysis using the FEM that vary according to the type of structure being analysed: beams and plates may use 1D or 2D approaches, shells and solids 2D or 3D approaches, and methods that work for one structure are typically not optimized to work for another. Finite Element Analysis of Structures Through Unified Formulation deals with the FEM used for the analysis of the mechanics of structures in the case of linear elasticity. The novelty of this book is that the finite elements (FEs) are formulated on the basis of a class of theories of structures known as the Carrera Unified Formulation (CUF). It formulates 1D, 2D and 3D FEs on the basis of the same ''fundamental nucleus'' that comes from geometrical relations and Hooke''s law, and presents both 1D and 2D refined FEs that only have displacement variables as in 3D elements. It also covers 1D...
Multicriteria Analysis of Assembling Buildings from Steel Frame Structures
Miniotaite, Ruta
2017-10-01
Steel frame structures are often used in the construction of public and industrial buildings. They are used for: all types of slope roofs; walls of newly-built public and industrial buildings; load bearing structures; roofs of renovated buildings. The process of assembling buildings from steel frame structures should be analysed as an integrated process influenced by such factors as construction materials and machinery used, the qualification level of construction workers, complexity of work, available finance. It is necessary to find a rational technological design solution for assembling buildings from steel frame structures by conducting a multiple criteria analysis. The analysis provides a possibility to evaluate the engineering considerations and find unequivocal solutions. The rational alternative of a complex process of assembling buildings from steel frame structures was found through multiple criteria analysis and multiple criteria evaluation. In multiple criteria evaluation of technological solutions for assembling buildings from steel frame structures by pairwise comparison method the criteria by significance are distributed as follows: durability is the most important criterion in the evaluation of alternatives; the price (EUR/unit of measurement) of a part of assembly process; construction workers’ qualification level (category); mechanization level of a part of assembling process (%), and complexity of assembling work (in points) are less important criteria.
Linear modal analysis of L-shaped beam structures
Georgiades, Fotios; Warminski, Jerzy; Cartmell, Matthew P.
2013-07-01
In this article a theoretical linear modal analysis of Euler-Bernoulli L-shaped beam structures is performed by solving two sets of coupled partial differential equations of motion. The first set, with two equations, corresponds to in-plane bending motions whilst the second set with four equations corresponds to out-of-plane motions with bending and torsion. The case is also shown of a single cantilever beam taking into account rotary inertia terms. At first for the case of examination of the results for the L-shaped beam structure, an individual modal analysis is presented for four selected beams which will be used for modelling an L-shaped beam structure; in order to investigate the influence of rotary inertia terms and shear effects. Then, a theoretical and numerical modal analysis is performed for four models of the L-shaped beam structure consisting of two sets of beams, in order to examine the effect of the orientation of the secondary beam (oriented in two ways) and also shear effects. The comparison of theoretical and finite element simulations shows a good agreement for both in-plane and out-of-plane motions, which validates the theoretical analysis. This work is essential to make progress with new investigations into the nonlinear equations for the L-shaped beam structures within Nonlinear Normal Mode theory.
Fuzzy Structures Analysis of Aircraft Panels in NASTRAN
Sparrow, Victor W.; Buehrle, Ralph D.
2001-01-01
This paper concerns an application of the fuzzy structures analysis (FSA) procedures of Soize to prototypical aerospace panels in MSC/NASTRAN, a large commercial finite element program. A brief introduction to the FSA procedures is first provided. The implementation of the FSA methods is then disclosed, and the method is validated by comparison to published results for the forced vibrations of a fuzzy beam. The results of the new implementation show excellent agreement to the benchmark results. The ongoing effort at NASA Langley and Penn State to apply these fuzzy structures analysis procedures to real aircraft panels is then described.
Robustness Analysis of Big Span Glulam Truss Structure
DEFF Research Database (Denmark)
Rajčié, V.; čizmar, D.; Kirkegaard, Poul Henning
2010-01-01
A progressive collapse of a building is defined as a catastrophic partial or total failure that starts from local damage, caused by a certain event, that can’t be absorbed by the structural system itself. In this paper an overview of principles, provisions and methods are given based on the codes...... (Eurocode 0 &1, Probabilistic model code etc.) Based on a project of big span glulam truss structure, build in Croatia few years ago, a probabilistic model is made with four failure elements. Reliability analysis of components is conducted and based on this a robustness analysis is preformed. It can...
A frequency domain analysis for damped space structures
Hagood, Nesbitt W.; Crawley, Edward F.
1989-01-01
A method is presented for the analysis of damped structural systems in which the structural components are represented by impedance models and analyzed in the frequency domain. Methods are presented to assemble and condense system impedance matrices, and then to identify approximate mass, stiffness, and damping matrices for systems whose impedances are complicated functions of frequency. Formulas are derived for determination of approximate values for system natural frequencies and damping using frequency domain quantities. The sensitivities of these approximate values to system parameter changes are analyzed. The implementation of these analysis tools is discussed and applied to a simple mechanical system.
RNAstructure: software for RNA secondary structure prediction and analysis
Directory of Open Access Journals (Sweden)
Mathews David H
2010-03-01
Full Text Available Abstract Background To understand an RNA sequence's mechanism of action, the structure must be known. Furthermore, target RNA structure is an important consideration in the design of small interfering RNAs and antisense DNA oligonucleotides. RNA secondary structure prediction, using thermodynamics, can be used to develop hypotheses about the structure of an RNA sequence. Results RNAstructure is a software package for RNA secondary structure prediction and analysis. It uses thermodynamics and utilizes the most recent set of nearest neighbor parameters from the Turner group. It includes methods for secondary structure prediction (using several algorithms, prediction of base pair probabilities, bimolecular structure prediction, and prediction of a structure common to two sequences. This contribution describes new extensions to the package, including a library of C++ classes for incorporation into other programs, a user-friendly graphical user interface written in JAVA, and new Unix-style text interfaces. The original graphical user interface for Microsoft Windows is still maintained. Conclusion The extensions to RNAstructure serve to make RNA secondary structure prediction user-friendly. The package is available for download from the Mathews lab homepage at http://rna.urmc.rochester.edu/RNAstructure.html.
Analysis and validation of carbohydrate three-dimensional structures
Lütteke, Thomas
2009-01-01
Knowledge of the three-dimensional structures of the carbohydrate molecules is indispensable for a full understanding of the molecular processes in which carbohydrates are involved, such as protein glycosylation or protein–carbohydrate interactions. The Protein Data Bank (PDB) is a valuable resource for three-dimensional structural information on glycoproteins and protein–carbohydrate complexes. Unfortunately, many carbohydrate moieties in the PDB contain inconsistencies or errors. This article gives an overview of the information that can be obtained from individual PDB entries and from statistical analyses of sets of three-dimensional structures, of typical problems that arise during the analysis of carbohydrate three-dimensional structures and of the validation tools that are currently available to scientists to evaluate the quality of these structures. PMID:19171971
Cryo-electron Microscopy Analysis of Structurally Heterogeneous Macromolecular Complexes.
Jonić, Slavica
2016-01-01
Cryo-electron microscopy (cryo-EM) has for a long time been a technique of choice for determining structure of large and flexible macromolecular complexes that were difficult to study by other experimental techniques such as X-ray crystallography or nuclear magnetic resonance. However, a fast development of instruments and software for cryo-EM in the last decade has allowed that a large range of complexes can be studied by cryo-EM, and that their structures can be obtained at near-atomic resolution, including the structures of small complexes (e.g., membrane proteins) whose size was earlier an obstacle to cryo-EM. Image analysis to identify multiple coexisting structures in the same specimen (multiconformation reconstruction) is now routinely done both to solve structures at near-atomic resolution and to study conformational dynamics. Methods for multiconformation reconstruction and latest examples of their applications are the focus of this review.
Cost benefit analysis on different configurations of berthing structure
Rajesh, G.; Saravanan, R.; Ravichandran, Vijaya; Parameswara Pandian, S.; Ramani Sujatha, Evangelin
2017-07-01
Port and harbors are essential for handling of the imports/exports of good transported through shipping. This paper discusses the different configuration of berthing structure, their design with respect to the site conditions and suitability. The analysis includes detailed load calculations conforming to the various codal provisions and design of the structure. The configuration of berthing structure considered are analyzed and designed using STAAD Pro for different combination of loads as per IS 4651. Bill of Quantities are prepared and final cost of construction is calculated. Factors affecting the construction and maintenance such as land availability, soil conditions, hydrodynamics of the site, dredging requirements, design ship size etc. are considered to finalize the configuration of the berthing structure. Result of the study shows that Diaphragm wall type of berthing structure is economic for Ennore port.
Time-dependent reliability analysis and condition assessment of structures
Energy Technology Data Exchange (ETDEWEB)
Ellingwood, B.R. [Johns Hopkins Univ., Baltimore, MD (United States)
1997-01-01
Structures generally play a passive role in assurance of safety in nuclear plant operation, but are important if the plant is to withstand the effect of extreme environmental or abnormal events. Relative to mechanical and electrical components, structural systems and components would be difficult and costly to replace. While the performance of steel or reinforced concrete structures in service generally has been very good, their strengths may deteriorate during an extended service life as a result of changes brought on by an aggressive environment, excessive loading, or accidental loading. Quantitative tools for condition assessment of aging structures can be developed using time-dependent structural reliability analysis methods. Such methods provide a framework for addressing the uncertainties attendant to aging in the decision process.
Numerical analysis of free vibrations of damped rotating structures
Gupta, K. K.
1977-01-01
This paper is concerned with the efficient numerical solution of damped and undamped free vibration problems of rotating structures. While structural discretization is achieved by the finite element method, the associated eigenproblem solution is effected by a combined Sturm sequence and inverse iteration technique that enables the computation of a few required roots only without having to compute any other. For structures of complex configurations, a modal synthesis technique is also presented, which is based on appropriate combinations of eigenproblem solution of various structural components. Such numerical procedures are general in nature, which fully exploit matrix sparsity inherent in finite element discretizations, and prove to be most efficient for the vibration analysis of any damped rotating structure, such as rotating machineries, helicopter and turbine blades, spinning space stations, among others.
Towards practical multiscale approach for analysis of reinforced concrete structures
Moyeda, Arturo; Fish, Jacob
2017-12-01
We present a novel multiscale approach for analysis of reinforced concrete structural elements that overcomes two major hurdles in utilization of multiscale technologies in practice: (1) coupling between material and structural scales due to consideration of large representative volume elements (RVE), and (2) computational complexity of solving complex nonlinear multiscale problems. The former is accomplished using a variant of computational continua framework that accounts for sizeable reinforced concrete RVEs by adjusting the location of quadrature points. The latter is accomplished by means of reduced order homogenization customized for structural elements. The proposed multiscale approach has been verified against direct numerical simulations and validated against experimental results.
STUDIES REGARDING THE STATIC ANALYSIS OF TRUSS STRUCTURES
Directory of Open Access Journals (Sweden)
URDEA Mihaela
2017-05-01
Full Text Available This paper refers to linear static analysis of truss and beams structures modelled in SolidWorks. In SolidWorks truss and frame elements are available only for staticstudies. For illustration it was modelled and studied the behaviour of a support of pipe. The truss is a welded structure modelled with Weldment Structural Members and it is often found in industrial constructions. During this study, there have been investigated the following FEA steps: Pre-Processing, Processing and Post-Processing.The results of this study are images corresponding to Axial Stress and The Maximum Displacement in different situations.
NRT Rotor Structural / Aeroelastic Analysis for the Preliminary Design Review
Energy Technology Data Exchange (ETDEWEB)
Ennis, Brandon Lee [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Paquette, Joshua A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2015-10-01
This document describes the initial structural design for the National Rotor Testbed blade as presented during the preliminary design review at Sandia National Laboratories on October 28- 29, 2015. The document summarizes the structural and aeroelastic requirements placed on the NRT rotor for satisfactory deployment at the DOE/SNL SWiFT experimental facility to produce high-quality datasets for wind turbine model validation. The method and result of the NRT blade structural optimization is also presented within this report, along with analysis of its satisfaction of the design requirements.
Mathematical Structure Common to Animal Growth Analysis and Space Expansion Analysis
Shimojo, Masataka
2016-01-01
This study was conducted to investigate mathematical structures common to animal growth analysis and space expansion analysis. Six particular functions for the growth analysis of the individual animal had a common mathematical structure composed of the respective function and its first and second derivatives. The standard model of the space expansion had a deceleration parameter composed of the scale factor and its first and second derivatives. The results obtained from this study suggested h...
Wang, K.; Jönsson, P.; Ekman, J.; Si, R.; Chen, Z. B.; Li, Y. G.; Chen, C. Y.; Yan, J.
2017-06-01
Using the multiconfiguration Dirac-Fock method and the second-order many-body perturbation theory method, highly accurate calculations are performed for the lowest 344 fine-structure levels arising from the 2s2 2p4 , 2s2 2p5 , 2p6 , 2s2 2p3 3 s , 2s2 2p3 3 p , 2s2 2p3 3 d , 2s2 2p4 3 s , 2s2 2p4 3 p , 2s2 2p4 3 d , 2p5 3 s , 2p5 3 p , 2p5 3 d , 2s2 2p3 4 s , 2s2 2p3 4 p , 2s2 2p3 4 d , 2s2 2p3 4 f , and 2s 2p4 4 s configurations in O-like Kr XXIX. Complete and consistent atomic data, including excitation energies, lifetimes, wavelengths, hyperfine structures, Landé gJ-factors, and E1, M1, E2, M2 transition rates, line strengths, and oscillator strengths among these 344 levels are obtained. Comparisons are made between our two different sets of results, as well as with the other available experimental and theoretical values. For O-like Kr only a few levels have been experimentally established. The accuracy of our calculated energies is however high enough to facilitate identifications of observed lines involving the n=3,4 levels. The calculated data are also useful for modeling and diagnosing fusion plasmas.
Energy Technology Data Exchange (ETDEWEB)
Batoo, Khalid Mujasam, E-mail: khalid.mujasam@gmail.com [King Abdullah Institute for Nanotechnology, King Saud University, P.O. Box-2455, Riyadh 11451 (Saudi Arabia); Salah, Dina [Department of Physics, Ain Shams University, Khalifa El-Maamon, Street, 11566 Cairo (Egypt); Kumar, Gagan; Kumar, Arun; Singh, Mahavir [Department of Physics, Himachal Pradesh University, Summer Hill, Shimla 171005 (India); Abd El-sadek, M. [Nanomaterials Lab, Physics Department, Faculty of Science, South Valley University, Qena 83523 (Egypt); Mir, Feroz Ahmad [University Science Instrumentation Centre, University of Kashmir, Srinagar 190006 (India); Imran, Ahamad [King Abdullah Institute for Nanotechnology, King Saud University, P.O. Box-2455, Riyadh 11451 (Saudi Arabia); Jameel, Daler Adil [School of Physics and Astronomy, Nottingham Nanotechnology and Nanoscience Center, University of Nottingham, NG7 2RD (United Kingdom)
2016-08-01
Ferrimagnetic oxides may contain single or multi domain particles which get converted into superparamagnetic state near a critical size. To explore the existence of these particles, we have made Mössbauer and magnetic studies of Cu{sup 2+} substitution effect in CoFe{sub 2−x}O{sub 4} Ferrites (0.0, 0.1, 0.2, 0.3, 0.4, and 0.5). All the samples have a cubic spinel structure with lattice parameters increasing linearly with increase in Cu content. The hysteresis loops yield a saturation magnetization, coercive field, and remanent magnetization that vary significantly with Cu content. The magnetic hysteresis curves shows a reduction in saturation magnetization and an increase in coercitivity with Cu{sup 2+} ion substitution. The anisotropy constant, K{sub 1,} is found strongly dependent on the composition of Cu{sup 2+} ions. The variation of saturation magnetization with increasing Cu{sup 2+} ion content has been explained in the light of Neel's molecular field theory. Mössbauer spectra at room temperature shows two ferrimagnetically relaxed Zeeman sextets. The dependence of Mössbauer parameters such as isomer shift, quadrupole splitting, line width and hyperfine magnetic field on Cu{sup 2+} ion concentration have been discussed. - Highlights: • Synthesis of the nanoparticles of Cu doped CoFe{sub 2}O{sub 4} ferrite nanoparticles. • The samples were characterized for the structural, morphological and magnetic studies using XRD, TEM, VSM and Mossbauer spectroscopy. • It has been found that the all the magnetic and Mossbauer parameters are diluted with the addition of Cu content in the CoFe{sub 2}O{sub 4} matrix. • The Mossbauer and magnetic properties were studied in the light of size of nanoparticles and also with respect to the doping composition.
Intermediate size inducer pump - structural analysis and transient deformation studies
Energy Technology Data Exchange (ETDEWEB)
Cheng, T.K.; Nishizaka, J.N.
1979-05-01
This report summarizes the structural and thermal transient deformation analysis of the Intermediate Size Inducer Pump. The analyses were performed in accordance to the requirements of N266ST310001, the specification for the ISIP. Results of stress analysis indicate that the thermal transient stress and strain are within the stress strain limits of RDT standard F9-4 which was used as a guide.
Use of a structural alphabet for analysis of short loops connecting repetitive structures
Fourrier, Laurent; Benros, Cristina; de Brevern, Alexandre G
2004-01-01
Background Because loops connect regular secondary structures, analysis of the former depends directly on the definition of the latter. The numerous assignment methods, however, can offer different definitions. In a previous study, we defined a structural alphabet composed of 16 average protein fragments, which we called Protein Blocks (PBs). They allow an accurate description of every region of 3D protein backbones and have been used in local structure prediction. In the present study, we use this structural alphabet to analyze and predict the loops connecting two repetitive structures. Results We first analyzed the secondary structure assignments. Use of five different assignment methods (DSSP, DEFINE, PCURVE, STRIDE and PSEA) showed the absence of consensus: 20% of the residues were assigned to different states. The discrepancies were particularly important at the extremities of the repetitive structures. We used PBs to describe and predict the short loops because they can help analyze and in part explain these discrepancies. An analysis of the PB distribution in these regions showed some specificities in the sequence-structure relationship. Of the amino acid over- or under-representations observed in the short loop databank, 20% did not appear in the entire databank. Finally, predicting 3D structure in terms of PBs with a Bayesian approach yielded an accuracy rate of 36.0% for all loops and 41.2% for the short loops. Specific learning in the short loops increased the latter by 1%. Conclusion This work highlights the difficulties of assigning repetitive structures and the advantages of using more precise descriptions, that is, PBs. We observed some new amino acid distributions in the short loops and used this information to enhance local prediction. Instead of describing entire loops, our approach predicts each position in the loops locally. It can thus be used to propose many different structures for the loops and to probe and sample their flexibility. It can
Analysis of a Model for the Morphological Structure of Renal Arterial Tree: Fractal Structure
Directory of Open Access Journals (Sweden)
Aurora Espinoza-Valdez
2013-01-01
experimental data measurements of the rat kidneys. The fractal dimension depends on the probability of sprouting angiogenesis in the development of the arterial vascular tree of the kidney, that is, of the distribution of blood vessels in the morphology generated by the analytical model. The fractal dimension might determine whether a suitable renal vascular structure is capable of performing physiological functions under appropriate conditions. The analysis can describe the complex structures of the development vasculature in kidney.
Composite Structure Modeling and Analysis of Advanced Aircraft Fuselage Concepts
Mukhopadhyay, Vivek; Sorokach, Michael R.
2015-01-01
NASA Environmentally Responsible Aviation (ERA) project and the Boeing Company are collabrating to advance the unitized damage arresting composite airframe technology with application to the Hybrid-Wing-Body (HWB) aircraft. The testing of a HWB fuselage section with Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) construction is presently being conducted at NASA Langley. Based on lessons learned from previous HWB structural design studies, improved finite-element models (FEM) of the HWB multi-bay and bulkhead assembly are developed to evaluate the performance of the PRSEUS construction. In order to assess the comparative weight reduction benefits of the PRSEUS technology, conventional cylindrical skin-stringer-frame models of a cylindrical and a double-bubble section fuselage concepts are developed. Stress analysis with design cabin-pressure load and scenario based case studies are conducted for design improvement in each case. Alternate analysis with stitched composite hat-stringers and C-frames are also presented, in addition to the foam-core sandwich frame and pultruded rod-stringer construction. The FEM structural stress, strain and weights are computed and compared for relative weight/strength benefit assessment. The structural analysis and specific weight comparison of these stitched composite advanced aircraft fuselage concepts demonstrated that the pressurized HWB fuselage section assembly can be structurally as efficient as the conventional cylindrical fuselage section with composite stringer-frame and PRSEUS construction, and significantly better than the conventional aluminum construction and the double-bubble section concept.
Imposed quasi-normality in covariance structure analysis
Koning, Ruud H.; Neudecker, H.; Wansbeek, T.
1993-01-01
In the analysis of covariance structures, the distance between an observed covariance matrix S of order k x k and C(6) E(S) is minimized by searching over the 8-space. The criterion leading to a best asymptotically normal (BAN) estimator of 0 is found by minimizing the difference between vecS and
Structural analysis and functional characteristics of greenhouses in ...
African Journals Online (AJOL)
This study was carried out to determine the structural analysis and functional characteristics of the greenhouses in the Mediterranean region where 87% of the greenhouse production area in Turkey is concentrated. Information about types, material and construction properties, placement and arrangement of greenhouses in ...
Efficient explicit formulation for practical fuzzy structural analysis
Indian Academy of Sciences (India)
This paper presents a practical approach based on High Dimensional Model Representation (HDMR) for analysing the response of structures with fuzzy parameters. The proposed methodology involves integrated ﬁnite element modelling, HDMR based response surface generation, and explicit fuzzy analysis procedures.
Quantitative Structure-Activity Relationship Analysis of the ...
African Journals Online (AJOL)
Quantitative Structure-Activity Relationship Analysis of the Anticonvulsant Activity of Some Benzylacetamides Based on Genetic Algorithm-Based Multiple Linear Regression. ... Methods: AM1 semiempirical quantum chemical calculation method was used to find the optimum 3D geometry of the studied molecules. Two types ...
Adjoint sensitivity analysis of high frequency structures with Matlab
Bakr, Mohamed; Demir, Veysel
2017-01-01
This book covers the theory of adjoint sensitivity analysis and uses the popular FDTD (finite-difference time-domain) method to show how wideband sensitivities can be efficiently estimated for different types of materials and structures. It includes a variety of MATLAB® examples to help readers absorb the content more easily.
A structural decomposition analysis of the emissions embodied in trade
Xu, Yan; Dietzenbacher, Erik
The aim of this study is to quantify the driving forces behind the growth of carbon dioxide emissions embodied in trade (EET). The World Input-output Database is used to estimate EET in 40 countries during 1995-2007 after which a structural decomposition analysis is applied. To avoid biases in the
Molecular cloning, sequence analysis and structure prediction of the ...
African Journals Online (AJOL)
Molecular cloning, sequence analysis and structure prediction of the related to b 0,+ amino acid transporter (rBAT) in Cyprinus carpio L. ... The amplified product was 2370 bp, including a 42 bp 5'-untranslated region, a 288 bp 3'-untranslated region, and a 2040 bp open reading frame (ORF), which encoded 679 amino acids ...
Stochastic Analysis of Offshore Steel Structures An Analytical Appraisal
Karadeniz, Halil
2013-01-01
Stochastic Analysis of Offshore Steel Structures provides a clear and detailed guide to advanced analysis methods of fixed offshore steel structures using 3D beam finite elements under random wave and earthquake loadings. Advanced and up-to-date research results are coupled with modern analysis methods and essential theoretical information to consider optimal solutions to structural issues. As these methods require and use knowledge of different subject matters, a general introduction to the key areas is provided. This is followed by in-depth explanations supported by design examples, relevant calculations and supplementary material containing related computer programmers. By combining this theoretical and practical approach Stochastic Analysis of Offshore Steel Structures cover a range of key concepts in detail including: · The basic principles of standard 3D beam finite elements and special connections, · Wave loading - from hydrodynamics to the calculation of wave load...
Synthesis, structure and Hirshfeld surface analysis, vibrational and ...
Indian Academy of Sciences (India)
The water molecule is placed between the layers formed by organic cations along the b axis. Net- work hydrogen-bonding and π–π interactions lead to the formation of a three-dimensional architecture. Hirshfeld surface analysis for visually analysing intermolecular interactions in crystal structures employing molecular sur-.
Population genetic structure and cladistic analysis of Trypanosoma brucei isolates
Agbo, E.C.; Clausen, P.H.; Buscher, P.; Majiwa, P.A.O.; Pas, te M.F.W.; Claassen, E.
2003-01-01
Using a novel multilocus DNA marker analysis method, we studied the population genetic structure of Trypansoma brucei stocks and derived clones isolated from animal and rhodesiense sleeping sickness patients during a national sleeping sickness control program in Mukono district, Uganda. We then
An analysis of the genetic diversity and genetic structure of ...
African Journals Online (AJOL)
Scientific approaches to conservation of threatened species depend on a good understanding of the genetic information of wild and artificial population. The genetic diversity and structure analysis of 10 Eucommia ulmoides population was analyzed using inter-simple sequence repeat (ISSR) markers in this paper.
Formation and Structural Analysis of Novel Dibornyl Ethers
African Journals Online (AJOL)
PROF P.T. KAYE
stereochemistry of novel dibornyl ethers, obtained by acid-catalysed condensation of camphor-derived α-hydroxybornanones. Keywords Dibornyl ethers; structure analysis; camphor derivatives. The results of some of our previous studies on the use of camphor-derived chiral auxiliaries in asymmetric synthesis1,2 indicated ...
Vibrational spectra and normal coordinate analysis on structure of ...
Indian Academy of Sciences (India)
journal of. December 2008 physics pp. 1291–1300. Vibrational spectra and normal coordinate analysis on structure of chlorambucil and thioguanine. S GUNASEKARAN1, S KUMARESAN2,∗, ... methoprexate are most effective in the treatment of leukemia [5–10] in children. Thioguanine interferes with the conversion of ...
Subsurface analysis of semiconductor structures with helium ion microscopy
van Gastel, Raoul; Hlawacek, G.; Zandvliet, Henricus J.W.; Poelsema, Bene
2012-01-01
We have used helium ion microscopy to directly track the subsurface diffusion of Pd through a Si stack in a non-invasive manner. The imaging and analysis of semiconductor structures along a direction perpendicular to the substrate is traditionally performed by making cross sections of a sample and
sequence stratigraphy and structural analysis of the emi field ...
African Journals Online (AJOL)
Timothy Ademakinwa
SEQUENCE STRATIGRAPHY AND STRUCTURAL ANALYSIS OF THE EMI FIELD,. OFFSHORE DEPOBELT, EASTERN NIGER DELTA BASIN, NIGERIA. 1*. 2. 2. Oresajo, B. S. , Adekeye, A. O. and Haruna, K. A.. 1Dept. of Geology, Federal University Birnin Kebbi, Birnin Kebbi. 2Dept. of Geology, University of Ilorin, Ilorin.
Preparation, structural analysis and dielectric properties of Bi $ _ { ...
Indian Academy of Sciences (India)
Home; Journals; Pramana – Journal of Physics; Volume 58; Issue 5-6. Preparation, structural analysis and dielectric properties of Bi La 1 − FeO3 perovskite. V L Mathe K K Patankar M B Kothale S B Kulkarni P B Joshi S A Patil. Colossal Magnetoresistance & Other Materials Volume 58 Issue 5-6 May-June 2002 pp ...
Stochastic Response and Reliability Analysis of Hysteretic Structures
DEFF Research Database (Denmark)
Mørk, Kim Jørgensen
During the last 30 years response analysis of structures under random excitation has been studied in detail. These studies are motivated by the fact that most of natures excitations, such as earthquakes, wind and wave loads exhibit randomly fluctuating characters. For safety reasons this randomne...
aRMSD: A Comprehensive Tool for Structural Analysis.
Wagner, Arne; Himmel, Hans-Jörg
2017-03-27
A new free tool for structural comparison is presented that combines existing and new features into a single software package. aRMSD incorporates the functions of establishing a pairwise correlation between the atoms of two molecular structures and the calculation of the optimal rotation matrix that minimizes the root-mean-square deviation (RMSD) between the molecules. The complexity of the Hungarian assignation problem is reduced by decomposing molecules into different subsets based on different atom or group types allowing for an efficient and robust treatment of large molecules while tolerating different substituents. Various weighting functions can be used for the calculation of RMSD values and similarity descriptors, and the utilization of coordinate uncertainties allows for the calculation of standard deviations for all calculated properties through error propagation. A new three-dimensional (3D) graphical representation that combines multiple aspects of structural information is presented which is useful in the analysis of structural similarity and diversity. The capabilities of aRMSD are demonstrated by selected examples that show how the program can be utilized in the analysis of structural changes and in the correlation of structure and activity in molecules. The source code of the program can be downloaded at https://github.com/armsd/aRMSD .
Loriot, Sébastien; Cazals, Frédéric; Bernauer, Julie
2010-04-15
The ever increasing number of structural biological data calls for robust and efficient software for analysis. Easy Structural Biology Template Library (ESBTL) is a lightweight C++ library that allows the handling of PDB data and provides a data structure suitable for geometric constructions and analyses. The parser and data model provided by this ready-to-use include-only library allows adequate treatment of usually discarded information (insertion code, atom occupancy, etc.) while still being able to detect badly formatted files. The template-based structure allows rapid design of new computational structural biology applications and is fully compatible with the new remediated PDB archive format. It also allows the code to be easy-to-use while being versatile enough to allow advanced user developments. ESBTL is freely available under the GNU General Public License from http://esbtl.sf.net. The web site provides the source code, examples, code snippets and documentation.
Raghavender, Upadhyayula Surya
2017-03-01
A comprehensive statistical analysis of the geometric parameters of peptide chains in a reduced dataset of protein-peptide complexes in Protein Data Bank (PDB) is presented. The angular variables describing the backbone conformations of amino acid residues in peptide chains shed insights into the conformational preferences of peptide residues interacting with protein partners. Nonparametric statistical approaches are employed to evaluate the interrelationships and associations in structural variables. Grouping of residues based on their structure into chemical classes reveals characteristic trends in parameter relationships. A comparison of canonical amino acid residues in free peptide structures in Cambridge structural database (CSD) with identical residues in PDB complexes, suggests that the information can be integrated from both the structural repositories enabling efficient and accurate modeling of biologically active peptides. © 2016 John Wiley & Sons A/S.
Quantitative analysis of structural neuroimaging of mesial temporal lobe epilepsy
Memarian, Negar; Thompson, Paul M; Engel, Jerome; Staba, Richard J
2013-01-01
Mesial temporal lobe epilepsy (MTLE) is the most common of the surgically remediable drug-resistant epilepsies. MRI is the primary diagnostic tool to detect anatomical abnormalities and, when combined with EEG, can more accurately identify an epileptogenic lesion, which is often hippocampal sclerosis in cases of MTLE. As structural imaging technology has advanced the surgical treatment of MTLE and other lesional epilepsies, so too have the analysis techniques that are used to measure different structural attributes of the brain. These techniques, which are reviewed here and have been used chiefly in basic research of epilepsy and in studies of MTLE, have identified different types and the extent of anatomical abnormalities that can extend beyond the affected hippocampus. These results suggest that structural imaging and sophisticated imaging analysis could provide important information to identify networks capable of generating spontaneous seizures and ultimately help guide surgical therapy that improves postsurgical seizure-freedom outcomes. PMID:24319498
Structural analysis of the foldecture derived from racemic peptide foldamers
Gong, Jintaek; Eom, Jae-Hoon; Jeong, Rokam; Driver, Russell W.; Lee, Hee-Seung
2017-08-01
The molecular packing structure of an elongated parallelogram plate shaped foldecture composed of a 1:1 racemic mixture of 11-helical peptide foldamers was resolved by powder X-ray diffraction (PXRD) analysis. A comprehensive Rietveld refinement procedure compensated for powder texture and identified the principal face of the foldecture. Each foldamer makes head-to-tail intermolecular hydrogen bonds, creating extended chains of single enantiomers that form a network of hydrophobic close contacts with foldamers of both the opposite and the same chiralities. An isosurface for anisotropic microstrain was calculated and found to be smallest along the x-axis, which is parallel to the network of intermolecular hydrogen bonds. Comparison with the single crystal structure found molecular packing motifs to be almost identical-a result infrequently observed in enantiopure foldectures. This is the first powder X-ray diffraction structural analysis of a foldecture composed of multiple components.
Structural Simulations and Conservation Analysis -Historic Building Information Model (HBIM)
Dore, C.; Murphy, M.; McCarthy, S.; Brechin, F.; Casidy, C.; Dirix, E.
2015-02-01
In this paper the current findings to date of the Historic Building Information Model (HBIM) of the Four Courts in Dublin are presented. The Historic Building Information Model (HBIM) forms the basis for both structural and conservation analysis to measure the impact of war damage which still impacts on the building. The laser scan survey was carried out in the summer of 2014 of the internal and external structure. After registration and processing of the laser scan survey, the HBIM was created of the damaged section of the building and is presented as two separate workflows in this paper. The first is the model created from historic data, the second a procedural and segmented model developed from laser scan survey of the war damaged drum and dome. From both models structural damage and decay simulations will be developed for documentation and conservation analysis.
Structural Health Monitoring Analysis for the Orbiter Wing Leading Edge
Yap, Keng C.
2010-01-01
This viewgraph presentation reviews Structural Health Monitoring Analysis for the Orbiter Wing Leading Edge. The Wing Leading Edge Impact Detection System (WLE IDS) and the Impact Analysis Process are also described to monitor WLE debris threats. The contents include: 1) Risk Management via SHM; 2) Hardware Overview; 3) Instrumentation; 4) Sensor Configuration; 5) Debris Hazard Monitoring; 6) Ascent Response Summary; 7) Response Signal; 8) Distribution of Flight Indications; 9) Probabilistic Risk Analysis (PRA); 10) Model Correlation; 11) Impact Tests; 12) Wing Leading Edge Modeling; 13) Ascent Debris PRA Results; and 14) MM/OD PRA Results.
Energy Technology Data Exchange (ETDEWEB)
Mao, Zhu; Wang, Fan; Lin, Jung-Fu; Fu, Suyu; Yang, Jing; Wu, Xiang; Okuchi, Takuo; Tomioka, Naotaka; Prakapenka, Vitali B.; Xiao, Yuming; Chow, Paul
2017-02-01
In this study, we performed synchrotron X-ray diffraction (XRD) and Mössbauer spectroscopy (SMS) measurements on two single-crystal bridgmanite samples [ Embedded Image and Embedded Image ] to investigate the combined effect of Fe and Al on the hyperfine parameters, lattice parameters, and equation of state (EoS) of bridgmanite up to 130 GPa. Our SMS results show that Fe2+ and Fe3+ in Bm6 and Al-Bm11 are predominantly located in the large pseudo-dodecahedral sites (A-site) at lower-mantle pressures. The observed drastic increase in the hyperfine quadrupole splitting (QS) between 13 and 32 GPa can be associated with an enhanced local distortion of the A-site Fe2+ in Bm6. In contrast to Bm6, the enhanced lattice distortion and the presence of extremely high QS values of Fe2+ are not observed in Al-Bm11 at high pressures. Our results here support the notion that the occurrence of the extremely high QS component of approximately 4 mm/s in bridgmanite is due to the lattice distortion in the high-spin (HS) A-site Fe2+, instead of the occurrence of the intermediate-spin state. Both A-site Fe2+ and Fe3+ in Bm6 and Al-Bm11 remain in the HS state at lower-mantle pressures. Together with XRD results, we present the first experimental evidence that the enhanced lattice distortion of A-site Fe2+ does not cause any detectable variation in the EoS parameters, but is associated with anomalous variations in the bond length, tilting angle, and shear strain in the octahedra of Bm6. Analysis of the obtained EoS parameters of bridgmanite at lower-mantle pressures indicates that the substitution of Fe in bridgmanite will cause an enhanced density and a reduced bulk sound velocity (VΦ), whereas the Al and Fe substitution has a reduced effect on density and a negligible effect on VΦ. These experimental results provide new insight into the correlation between lattice, hyperfine, and EoS parameters of bridgmanite in the Earth’s lower mantle.
ACT Payload Shroud Structural Concept Analysis and Optimization
Zalewski, Bart B.; Bednarcyk, Brett A.
2010-01-01
Aerospace structural applications demand a weight efficient design to perform in a cost effective manner. This is particularly true for launch vehicle structures, where weight is the dominant design driver. The design process typically requires many iterations to ensure that a satisfactory minimum weight has been obtained. Although metallic structures can be weight efficient, composite structures can provide additional weight savings due to their lower density and additional design flexibility. This work presents structural analysis and weight optimization of a composite payload shroud for NASA s Ares V heavy lift vehicle. Two concepts, which were previously determined to be efficient for such a structure are evaluated: a hat stiffened/corrugated panel and a fiber reinforced foam sandwich panel. A composite structural optimization code, HyperSizer, is used to optimize the panel geometry, composite material ply orientations, and sandwich core material. HyperSizer enables an efficient evaluation of thousands of potential designs versus multiple strength and stability-based failure criteria across multiple load cases. HyperSizer sizing process uses a global finite element model to obtain element forces, which are statistically processed to arrive at panel-level design-to loads. These loads are then used to analyze each candidate panel design. A near optimum design is selected as the one with the lowest weight that also provides all positive margins of safety. The stiffness of each newly sized panel or beam component is taken into account in the subsequent finite element analysis. Iteration of analysis/optimization is performed to ensure a converged design. Sizing results for the hat stiffened panel concept and the fiber reinforced foam sandwich concept are presented.
An Error Analysis of Structured Light Scanning of Biological Tissue
DEFF Research Database (Denmark)
Jensen, Sebastian Hoppe Nesgaard; Wilm, Jakob; Aanæs, Henrik
2017-01-01
This paper presents an error analysis and correction model for four structured light methods applied to three common types of biological tissue; skin, fat and muscle. Despite its many advantages, structured light is based on the assumption of direct reflection at the object surface only....... This assumption is violated by most biological material e.g. human skin, which exhibits subsurface scattering. In this study, we find that in general, structured light scans of biological tissue deviate significantly from the ground truth. We show that a large portion of this error can be predicted with a simple......, statistical linear model based on the scan geometry. As such, scans can be corrected without introducing any specially designed pattern strategy or hardware. We can effectively reduce the error in a structured light scanner applied to biological tissue by as much as factor of two or three....
Lumped mass modelling for the dynamic analysis of aircraft structures
Abu-Saba, Elias G.; Shen, Ji Yao; Mcginley, William M.; Montgomery, Raymond C.
1992-01-01
Aircraft structures may be modelled by lumping the masses at particular strategic points and the flexibility or stiffness of the structure is obtained with reference to these points. Equivalent moments of inertia for the section at these positions are determined. The lumped masses are calculated based on the assumption that each point will represent the mass spread on one half of the space on each side. Then these parameters are used in the differential equation of motion and the eigen characteristics are determined. A comparison is made with results obtained by other established methods. The lumped mass approach in the dynamic analysis of complicated structures provides an easier means of predicting the dynamic characteristics of these structures. It involves less computer time and avoids computational errors that are inherent in the numerical solution of complicated systems.
Structural parameter identifiability analysis for dynamic reaction networks
DEFF Research Database (Denmark)
Davidescu, Florin Paul; Jørgensen, Sten Bay
2008-01-01
where for a given set of measured variables it is desirable to investigate which parameters may be estimated prior to spending computational effort on the actual estimation. This contribution addresses the structural parameter identifiability problem for the typical case of reaction network models....... The proposed analysis is performed in two phases. The first phase determines the structurally identifiable reaction rates based on reaction network stoichiometry. The second phase assesses the structural parameter identifiability of the specific kinetic rate expressions using a generating series expansion...... method based on Lie derivatives. The proposed systematic two phase methodology is illustrated on a mass action based model for an enzymatically catalyzed reaction pathway network where only a limited set of variables is measured. The methodology clearly pinpoints the structurally identifiable parameters...
Total systems design analysis of high performance structures
Verderaime, V.
1993-01-01
Designer-control parameters were identified at interdiscipline interfaces to optimize structural systems performance and downstream development and operations with reliability and least life-cycle cost. Interface tasks and iterations are tracked through a matrix of performance disciplines integration versus manufacturing, verification, and operations interactions for a total system design analysis. Performance integration tasks include shapes, sizes, environments, and materials. Integrity integrating tasks are reliability and recurring structural costs. Significant interface designer control parameters were noted as shapes, dimensions, probability range factors, and cost. Structural failure concept is presented, and first-order reliability and deterministic methods, benefits, and limitations are discussed. A deterministic reliability technique combining benefits of both is proposed for static structures which is also timely and economically verifiable. Though launch vehicle environments were primarily considered, the system design process is applicable to any surface system using its own unique filed environments.
Total systems design analysis of high performance structures
Verderaime, V.
1993-11-01
Designer-control parameters were identified at interdiscipline interfaces to optimize structural systems performance and downstream development and operations with reliability and least life-cycle cost. Interface tasks and iterations are tracked through a matrix of performance disciplines integration versus manufacturing, verification, and operations interactions for a total system design analysis. Performance integration tasks include shapes, sizes, environments, and materials. Integrity integrating tasks are reliability and recurring structural costs. Significant interface designer control parameters were noted as shapes, dimensions, probability range factors, and cost. Structural failure concept is presented, and first-order reliability and deterministic methods, benefits, and limitations are discussed. A deterministic reliability technique combining benefits of both is proposed for static structures which is also timely and economically verifiable. Though launch vehicle environments were primarily considered, the system design process is applicable to any surface system using its own unique filed environments.
Estructuras de elevadores de carga. // Dumbwaiter structure stress analysis.
Directory of Open Access Journals (Sweden)
G. Escobar Travieso
2006-09-01
Full Text Available Este trabajo tiene como objetivo analizar las tensiones y deformaciones que ocurren en las estructuras del marco de carro,plataforma y cabina de elevadores de carga mediante la aplicación del Método de los Elementos Finitos, específicamentedel montaplatos de 300 Kg. de capacidad, con vista a realizar el análisis de resistencia, racionalización del peso y material ylas posibles vías de solución.Palabras claves: Elevador de carga, estructuras, análisis de tensiones, elementos finitos.________________________________________________________________________________AbstractThis paper deals with the tension and deformation analysis in structures of lifter mark, platform and cabin offreight lifters by means of the Finite Elements Method, specifically the 300 kgs capacity dumbwaiter, in orderto carry out the resistance analysis, weight and material rationalization.Key words: Dumbwaiter, structures, stress analysis, finite elements.
CARIBBEAN OFFSHORE CORPORATE STRUCTURES UNDER A SWOT ANALYSIS
Directory of Open Access Journals (Sweden)
Ana-Maria GEAMÃNU
2015-04-01
Full Text Available Tax havens have long been under the attention of numerous Governments and International Organizations which triggered the concern of an uneven playing field in the taxation area. As a result numerous amendments have been made to both their commercial and tax legislations in order to be in line with the internationally agreed tax standards. The aim of this article is to conduct a SWOT analysis on the offshore corporate structures found in the Caribbean landscape. Based on a selection process of the most commonly recognized tax havens in the Caribbean region and an analysis of their offshore companies at the level of incorporation, administration, activities conducted and costs, a set of frequently met characteristics have been identified which stand at the basis of the SWOT analysis. The results stand to present a comprehensive four dimension framework of the offshore corporate structures in regards to their strengths, weaknesses, opportunities and threats.
Design and Analysis of Muon Beam Stop Support Structures
Energy Technology Data Exchange (ETDEWEB)
Okafor, Udenna [Northern Illinois Univ., DeKalb, IL (United States)
2015-01-01
The primary objective of this thesis is to design and analyze support structures to be used in the installation, test and final positioning of the MBS throughout the life of the Mu2e experiment. There several requirements for the MBS imposed by both the scope of the experiment and, other components within the DS bore. The functions of the MBS are: 1. To limit the induced rates in the Tracker, the Calorimeter and the Cosmic Ray Veto due to backsplash-and-secondary interactions, and 2. To reduce radiation levels external to the Detector solenoid. The structures used in supporting the MBS will also adhere to requirements imposed by its functions. These requirements are critical to the support structures and affect design decisions. Other requirements critical to the design are imposed by the weight, positional tolerance and assembly procedure of the MBS, and also, the magnetic field and vacuum dose rate of the DS bore. A detailed breakdown of how each requirement affects the structural design can be found in chapter 2. Chapter 3 describes the design of each support structure and its attachment to the MBS while chapter 4 describes the results from structural analysis of the support structures. Chapter 5 describes evaluation for the design through testing and calculations while the conclusion in chapter 6 reports the current status at the time of this thesis submission with a plan for future work to be completed until final design and installation.
Structural Analysis of Chemokine Receptor–Ligand Interactions
2017-01-01
This review focuses on the construction and application of structural chemokine receptor models for the elucidation of molecular determinants of chemokine receptor modulation and the structure-based discovery and design of chemokine receptor ligands. A comparative analysis of ligand binding pockets in chemokine receptors is presented, including a detailed description of the CXCR4, CCR2, CCR5, CCR9, and US28 X-ray structures, and their implication for modeling molecular interactions of chemokine receptors with small-molecule ligands, peptide ligands, and large antibodies and chemokines. These studies demonstrate how the integration of new structural information on chemokine receptors with extensive structure–activity relationship and site-directed mutagenesis data facilitates the prediction of the structure of chemokine receptor–ligand complexes that have not been crystallized. Finally, a review of structure-based ligand discovery and design studies based on chemokine receptor crystal structures and homology models illustrates the possibilities and challenges to find novel ligands for chemokine receptors. PMID:28165741
A Study of Coherent Structures using Wavelet Analysis
Energy Technology Data Exchange (ETDEWEB)
Kaspersen, J.H.
1996-05-01
Turbulence is important in many fields of engineering, for example in estimating drag or minimizing drag on surfaces. It is known that turbulent flows contain coherent structures, which implies that a turbulent shear flow can be decomposed into coherent structures and random motion. It is generally accepted that coherent structures are responsible for significant transport of mass, heat and momentum. This doctoral thesis presents and discusses a new algorithm to detect coherent structures based on Wavelet transformations, a transform similar to the Fourier transform but providing information on both frequency and scale. The new detection scheme does not require any predefined threshold or integration time, and its general performance is found to be very good. Wind tunnel experiments were performed to obtain data for analysis. Scalograms resulting from the Wavelet transform show clearly that coherent structures exist in turbulent flows. These structures are shown to contribute considerably to the shear stresses. The contribution from the organized motion to the normal stresses close to the wall appears to be considerably smaller. Direct Navier Stokes (DNS) channel flow seems to be more organized than Zero Pressure Gradient (ZPG) flows. The topology of ZPG flows was studied using a multiple hot wire arrangement and conditionally averaged streamlines based on detections from the Wavelet method are presented. It is shown that the coherent structures produce large amounts of both vorticity and strain at the detection point. 56 refs., 92 figs., 3 tabs.
DEFF Research Database (Denmark)
Hansen, P. E.; Nevald, Rolf
1977-01-01
The nuclear-magnetic-resonance rotation spectra for the fluorine and lithium nuclei in LiTbF4, LiDyF4, LiHoF4, and LiErF4 have been obtained at 295 K. They are separated in contributions from the dipole and the transferred hyperfine interactions. In general, the latter consists of an isotropic part...
Somayajulu, D. R. S; IWNMS 2004
2005-01-01
Proceedings of the Baroda Workshop IWNMS 2004, held in Baroda, India, 10-14 February, 2004 Researchers and graduate students interested in the Mössbauer Effect and its applications will find this volume indispensable. The volume presents the most recent developments in the methodology of Mössbauer spectroscopy. Reprinted from Hyperfine Interactions (HYPE) Volume 160, 1-4
Python package for model STructure ANalysis (pySTAN)
Van Hoey, Stijn; van der Kwast, Johannes; Nopens, Ingmar; Seuntjens, Piet
2013-04-01
The selection and identification of a suitable hydrological model structure is more than fitting parameters of a model structure to reproduce a measured hydrograph. The procedure is highly dependent on various criteria, i.e. the modelling objective, the characteristics and the scale of the system under investigation as well as the available data. Rigorous analysis of the candidate model structures is needed to support and objectify the selection of the most appropriate structure for a specific case (or eventually justify the use of a proposed ensemble of structures). This holds both in the situation of choosing between a limited set of different structures as well as in the framework of flexible model structures with interchangeable components. Many different methods to evaluate and analyse model structures exist. This leads to a sprawl of available methods, all characterized by different assumptions, changing conditions of application and various code implementations. Methods typically focus on optimization, sensitivity analysis or uncertainty analysis, with backgrounds from optimization, machine-learning or statistics amongst others. These methods also need an evaluation metric (objective function) to compare the model outcome with some observed data. However, for current methods described in literature, implementations are not always transparent and reproducible (if available at all). No standard procedures exist to share code and the popularity (and amount of applications) of the methods is sometimes more dependent on the availability than the merits of the method. Moreover, new implementations of existing methods are difficult to verify and the different theoretical backgrounds make it difficult for environmental scientists to decide about the usefulness of a specific method. A common and open framework with a large set of methods can support users in deciding about the most appropriate method. Hence, it enables to simultaneously apply and compare different
Structural Optimization of Slender Robot Arm Based on Sensitivity Analysis
Directory of Open Access Journals (Sweden)
Zhong Luo
2012-01-01
Full Text Available An effective structural optimization method based on a sensitivity analysis is proposed to optimize the variable section of a slender robot arm. The structure mechanism and the operating principle of a polishing robot are introduced firstly, and its stiffness model is established. Then, a design of sensitivity analysis method and a sequential linear programming (SLP strategy are developed. At the beginning of the optimization, the design sensitivity analysis method is applied to select the sensitive design variables which can make the optimized results more efficient and accurate. In addition, it can also be used to determine the scale of moving step which will improve the convergency during the optimization process. The design sensitivities are calculated using the finite difference method. The search for the final optimal structure is performed using the SLP method. Simulation results show that the proposed structure optimization method is effective in enhancing the stiffness of the robot arm regardless of the robot arm suffering either a constant force or variable forces.
Coordinate-based versus structural approaches to brain image analysis.
Mangin, J-F; Rivière, D; Coulon, O; Poupon, C; Cachia, A; Cointepas, Y; Poline, J-B; Le Bihan, D; Régis, J; Papadopoulos-Orfanos, D
2004-02-01
A basic issue in neurosciences is to look for possible relationships between brain architecture and cognitive models. The lack of architectural information in magnetic resonance images, however, has led the neuroimaging community to develop brain mapping strategies based on various coordinate systems without accurate architectural content. Therefore, the relationships between architectural and functional brain organizations are difficult to study when analyzing neuroimaging experiments. This paper advocates that the design of new brain image analysis methods inspired by the structural strategies often used in computer vision may provide better ways to address these relationships. The key point underlying this new framework is the conversion of the raw images into structural representations before analysis. These representations are made up of data-driven elementary features like activated clusters, cortical folds or fiber bundles. Two classes of methods are introduced. Inference of structural models via matching across a set of individuals is described first. This inference problem is illustrated by the group analysis of functional statistical parametric maps (SPMs). Then, the matching of new individual data with a priori known structural models is described, using the recognition of the cortical sulci as a prototypical example.
Emerging Methods for Structural Analysis of Protein Aggregation.
Khan, Eshan; Mishra, Subodh K; Kumar, Amit
2017-01-01
Protein misfolding and aggregation is a key attribute of different neurodegenerative diseases. Misfolded and aggregated proteins are intrinsically disordered and rule out structure based drug design. The comprehensive characterization of misfolded proteins and associated aggregation pathway is prerequisite to develop therapeutics for neurodegenerative diseases caused due to the protein aggregation. Visible protein aggregates used to be the final stage during aggregation mechanism. The structural analysis of intermediate steps in such protein aggregates will help us to discern the conformational role and subsequently involved pathways. The structural analysis of protein aggregation using various biophysical methods may aid for improved therapeutics for protein misfolding and aggregation related neurodegenerative diseases. In this mini review, we have summarized different spectroscopic methods such as fluorescence spectroscopy, circular dichroism (CD), nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy for structural analysis of protein aggregation. We believe that the understanding of invisible intermediate of misfolded proteins and the key steps involved during protein aggregation mechanisms may advance the therapeutic approaches for targeting neurological diseases that are caused due to misfolded proteins. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.
Linear algebra-based matrix structural analysis of two-dimensional reciprocal structures
DEFF Research Database (Denmark)
Parigi, Dario
2017-01-01
The following paper proposes a formulation for the extension of linear algebra-based matrix structural analysis to assemblies in which elements join in intermediate points. Such a formulation in particular must include now the possibility to describe an expanded set of joints as prismatic joint...
Network structure detection and analysis of Shanghai stock market
Directory of Open Access Journals (Sweden)
Sen Wu
2015-04-01
Full Text Available Purpose: In order to investigate community structure of the component stocks of SSE (Shanghai Stock Exchange 180-index, a stock correlation network is built to find the intra-community and inter-community relationship. Design/methodology/approach: The stock correlation network is built taking the vertices as stocks and edges as correlation coefficients of logarithm returns of stock price. It is built as undirected weighted at first. GN algorithm is selected to detect community structure after transferring the network into un-weighted with different thresholds. Findings: The result of the network community structure analysis shows that the stock market has obvious industrial characteristics. Most of the stocks in the same industry or in the same supply chain are assigned to the same community. The correlation of the internal stock prices’ fluctuation is closer than in different communities. The result of community structure detection also reflects correlations among different industries. Originality/value: Based on the analysis of the community structure in Shanghai stock market, the result reflects some industrial characteristics, which has reference value to relationship among industries or sub-sectors of listed companies.
Kamiński, M.; Szafran, J.
2015-05-01
The main purpose of this work is to verify the influence of the weighting procedure in the Least Squares Method on the probabilistic moments resulting from the stability analysis of steel skeletal structures. We discuss this issue also in the context of the geometrical nonlinearity appearing in the Stochastic Finite Element Method equations for the stability analysis and preservation of the Gaussian probability density function employed to model the Young modulus of a structural steel in this problem. The weighting procedure itself (with both triangular and Dirac-type) shows rather marginal influence on all probabilistic coefficients under consideration. This hybrid stochastic computational technique consisting of the FEM and computer algebra systems (ROBOT and MAPLE packages) may be used for analogous nonlinear analyses in structural reliability assessment.
The Metodology of Concept Structure Analysis: Cognitive and Linguoculturological Aspects
Directory of Open Access Journals (Sweden)
Fedoryuk Liliya
2016-12-01
Full Text Available Background: The anthropocentric paradigm has set new challenges in the study of language, it requires new methods of analysis of these units and categories. Anthropocentric paradigm has developed a number of areas of research of the concepts: psychological, logical, philosophical, linguoculturological, cognitive. We investigate the concept of DEATH based on Ukrainian literature, so as the relevant ones for the research we consider cognitive and linguoculturological approaches. Purpose: The purpose of research is to analyze the most current methods of concepts study, to identify on which one of them the thesis “The Concept DEATH in the Ukrainian Сognitive-Linguistic World Picture: Structure, Statics and Dynamics” will be based. Results: The study of the concept DEATH in the thesis “The Concept DEATH in the Ukrainian Сognitive-Linguistic World Picture: Structure, Statics and Dynamics” will be based on the analysis techniques by M. Pimenova, Zh. Krasnobaieva-Chorna and V. Maslova mentioned above. We offer the phased analysis model of the concept DEATH: 1 identification of motivating features of the concept DEATH; 2 characteristics of conceptual features of the concept; 3 revealing of figurative conceptual features based on the Ukrainian literature of XIX – early XX and XX – early XXI centuries; 4 studying of symbolic features of the concept DEATH; 5 identification the ironic features of the concept; 6 analysis of associative experiment; 7 research of the concept DEATH scenarios, analysis of its components. Thus, within the cognitive and linguoculturological approaches, the most productive methods of the concept research are: modeling of semantic fields; method of contextual analysis; method of modeling and research of conceptual metaphors, and others. Discussion: Seven-stages analysis enables to obtain the most complete information about the structural specific of the concept DEATH, its place in the national conceptual sphere and the
Synthesis of aircraft structures using integrated design and analysis methods
Sobieszczanski-Sobieski, J.; Goetz, R. C.
1978-01-01
A systematic research is reported to develop and validate methods for structural sizing of an airframe designed with the use of composite materials and active controls. This research program includes procedures for computing aeroelastic loads, static and dynamic aeroelasticity, analysis and synthesis of active controls, and optimization techniques. Development of the methods is concerned with the most effective ways of integrating and sequencing the procedures in order to generate structural sizing and the associated active control system, which is optimal with respect to a given merit function constrained by strength and aeroelasticity requirements.
The Riccati transfer matrix method. [for computerized structural analysis
Horner, G. C.; Pilkey, W. D.
1977-01-01
The Riccati transfer matrix method is a new technique for analyzing structural members. This new technique makes use of an existing large catalog of transfer matrices for various structural members such as rotating shafts. The numerical instability encountered when calculating high resonant frequencies, static response of a flexible member on a stiff foundation, or the response of a long member by the transfer matrix method is eliminated by the Riccati transfer matrix method. The computational time and storage requirements of the Riccati transfer matrix method are about half the values for the transfer matrix method. A rotating shaft analysis demonstrates the numerical accuracy of the method.
Linearly Polarized IR Spectroscopy Theory and Applications for Structural Analysis
Kolev, Tsonko
2011-01-01
A technique that is useful in the study of pharmaceutical products and biological molecules, polarization IR spectroscopy has undergone continuous development since it first emerged almost 100 years ago. Capturing the state of the science as it exists today, "Linearly Polarized IR Spectroscopy: Theory and Applications for Structural Analysis" demonstrates how the technique can be properly utilized to obtain important information about the structure and spectral properties of oriented compounds. The book starts with the theoretical basis of linear-dichroic infrared (IR-LD) spectroscop
Modeling high temperature materials behavior for structural analysis
Naumenko, Konstantin
2016-01-01
This monograph presents approaches to characterize inelastic behavior of materials and structures at high temperature. Starting from experimental observations, it discusses basic features of inelastic phenomena including creep, plasticity, relaxation, low cycle and thermal fatigue. The authors formulate constitutive equations to describe the inelastic response for the given states of stress and microstructure. They introduce evolution equations to capture hardening, recovery, softening, ageing and damage processes. Principles of continuum mechanics and thermodynamics are presented to provide a framework for the modeling materials behavior with the aim of structural analysis of high-temperature engineering components.
Analysis of regular structures third degree based on chordal rings
DEFF Research Database (Denmark)
Bujnowski, Slawomir; Dubalski, Bozydar; Pedersen, Jens Myrup
2009-01-01
. In the first part of paper, formulas for the basic parameters diameter and average path length were derived using optimal/ideal graphs, and used for indicating transmission properties of the structures. These analytical results were confirmed by comparison to a large number of computations on real graphs. In...... This paper presents an analysis of modified chordal rings third degree (CR3m) and modified double ring structure (N2Rm), which can be used as models of real networks. The proposed solutions are novel and different from the ones currently used since they have two chords of different lengths...
Probabilistic Analysis of Structural Member from Recycled Aggregate Concrete
Broukalová, I.; Šeps, K.
2017-09-01
The paper aims at the topic of sustainable building concerning recycling of waste rubble concrete from demolition. Considering demands of maximising recycled aggregate use and minimising of cement consumption, composite from recycled concrete aggregate was proposed. The objective of the presented investigations was to verify feasibility of the recycled aggregate cement based fibre reinforced composite in a structural member. Reliability of wall from recycled aggregate fibre reinforced composite was assessed in a probabilistic analysis of a load-bearing capacity of the wall. The applicability of recycled aggregate fibre reinforced concrete in structural applications was demonstrated. The outcomes refer to issue of high scatter of material parameters of recycled aggregate concretes.
STRUCTURE ANALYSIS OF THE EVOLUTION OF PRIVATE CONSUMPTION IN ROMANIA
Directory of Open Access Journals (Sweden)
Raluca M. BĂLĂ
2014-06-01
Full Text Available This paper aims to analyze the evolution of the private consumption structure in Romania in the last twenty years surprising three main periods that influenced the composition of economic welfare of romanian citizens: the transition period to the market economy after the fall of communist regime, the period of economic stabilization and sustained growth and the period of financial and economic crisis. The analysis reveals the modifications in the structure of private consumption throughout the three main phases surprised in the Romanian economy and shows the influence of these changes on the economic welfare of the population.
PARAMETERS AFFECTING THE STRUCTURAL ANALYSIS OF A TUNNEL STRUCTURE EXPOSED TO FIRE
Directory of Open Access Journals (Sweden)
Omid Pouran
2016-12-01
Full Text Available Behaviour of cut-and-cover tunnels exposed to fire should be analysed by using a realistic structural model that takes account of mechanical and thermal effects on the structure. This has been performed with the aid of Finite Element (FE software package called SOFiSTiK in parallel, for two types of elements as a scope of research project financed by the German Bundesanstalt für Straßenwesen BAST. Since the stiffness of the structure at elevated temperatures is highly affected, a realistic model of structural behaviour of the tunnel could be only achieved by considering the nonlinear analysis of the structure. This has been performed for a 2–cell cut and cover tunnel by taking account of simultaneous reduction of stiffness and strength and the time-dependent increasing indirect effects due to axial constraints and temperature gradients induced by elevated temperatures. The thermal analyses have been performed and the effects were implemented into the structural model by the multi-layered strain model. The stress–strain model proposed by EN 1992-1-2 is implemented for the elevated temperature. Since there was sufficient amount of Polypropylene fibres in the concrete mixtures, modelling of spalling was excluded from the analysis. The critical corresponding stresses and material behaviour are compared and interpreted at different time stages. The main parameters affecting the accuracy and convergence of the results of structural analysis for the used model are identified: defining a realistic fire action, using concrete material model fulfilling the requirements of fire situation in tunnels, defining appropriate time intervals for load implementations. These parameters along with other parameters, which influence the results to a lesser degree, are identified and investigated in this paper.
Whiting, Daniel J; Adams, Charles S; Hughes, Ifan G
2016-01-01
Applying large magnetic fields to gain access to the hyperfine Paschen-Back regime can isolate three-level systems in a hot alkali metal vapors, thereby simplifying usually complex atom-light interactions. We use this method to make the first direct measurement of the $|\\langle\\mathrm{5P}| er||\\mathrm{5D}\\rangle|$ matrix element in $^{87}$Rb. An analytic model with only three-levels accurately models the experimental electromagnetically induced transparency spectra and extracted Rabi-frequencies are used to determine the dipole matrix element. We measure $|\\langle\\mathrm{5P}_{3/2}|er||\\mathrm{5D}_{5/2}\\rangle| = (2.290\\pm0.002_{\\rm stat}\\pm0.05_{\\rm syst})~ea_{0}$ which is in excellent agreement with the theoretical calculations of Safronova, Williams and Clark, Phys. Rev. A 69(2), 022509 (2004).
The {sup 57}Fe hyperfine interactions in the iron-bearing phases in some LL ordinary chondrites
Energy Technology Data Exchange (ETDEWEB)
Oshtrakh, M. I., E-mail: oshtrakh@gmail.com; Maksimova, A. A.; Grokhovsky, V. I.; Petrova, E. V.; Semionkin, V. A. [Ural Federal University, Department of Physical Techniques and Devices for Quality Control, Institute of Physics and Technology (Russian Federation)
2016-12-15
The study of several LL ordinary chondrites such as NWA 6286 LL6, NWA 7857 LL6 and Chelyabinsk LL5 fragments with different lithology was carried out using scanning electron microscopy with energy dispersion spectroscopy, X-ray diffraction and {sup 57}Fe Mössbauer spectroscopy with a high velocity resolution at 295 K. Small variations in the {sup 57}Fe hyperfine parameters were revealed for the M1 and M2 sites in olivine, orthopyroxene and clinopyroxene as well as for α-Fe(Ni, Co), α{sub 2}-Fe(Ni, Co) and γ-Fe(Ni, Co) phases, and for troilite in different samples of studied LL ordinary chondrites.
Joshi, G.; Miller, R.; Ogden, L.; Kavand, M.; Jamali, S.; Ambal, K.; Venkatesh, S.; Schurig, D.; Malissa, H.; Lupton, J. M.; Boehme, C.
2016-09-01
Separating the influence of hyperfine from spin-orbit interactions in spin-dependent carrier recombination and dissociation processes necessitates magnetic resonance spectroscopy over a wide range of frequencies. We have designed compact and versatile coplanar waveguide resonators for continuous-wave electrically detected magnetic resonance and tested these on organic light-emitting diodes. By exploiting both the fundamental and higher-harmonic modes of the resonators, we cover almost five octaves in resonance frequency within a single setup. The measurements with a common π-conjugated polymer as the active material reveal small but non-negligible effects of spin-orbit interactions, which give rise to a broadening of the magnetic resonance spectrum with increasing frequency.
Energy Technology Data Exchange (ETDEWEB)
Joshi, G.; Miller, R.; Ogden, L.; Kavand, M.; Jamali, S.; Ambal, K.; Malissa, H.; Boehme, C., E-mail: boehme@physics.utah.edu [Department of Physics and Astronomy, University of Utah, Salt Lake City, Utah 84112 (United States); Venkatesh, S.; Schurig, D. [Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, Utah 84112 (United States); Lupton, J. M. [Department of Physics and Astronomy, University of Utah, Salt Lake City, Utah 84112 (United States); Institut für Experimentelle und Angewandte Physik, Universität Regensburg, D-93040 Regensburg (Germany)
2016-09-05
Separating the influence of hyperfine from spin-orbit interactions in spin-dependent carrier recombination and dissociation processes necessitates magnetic resonance spectroscopy over a wide range of frequencies. We have designed compact and versatile coplanar waveguide resonators for continuous-wave electrically detected magnetic resonance and tested these on organic light-emitting diodes. By exploiting both the fundamental and higher-harmonic modes of the resonators, we cover almost five octaves in resonance frequency within a single setup. The measurements with a common π-conjugated polymer as the active material reveal small but non-negligible effects of spin-orbit interactions, which give rise to a broadening of the magnetic resonance spectrum with increasing frequency.
Energy Technology Data Exchange (ETDEWEB)
Zemcik, T. (Ceskoslovenska Akademie Ved, Brno (Czechoslovakia). Ustav Fyzikalni Metalurgie); Kuzmann, E. (Eoetvoes Lorand Tudomanyegyetem, Budapest (Hungary). Lab. of Nuclear Chemistry); Hemschik, H. (Akademie der Wissenschaften, Dresden (Germany, F.R.). Zentralinstitut fuer Festkoerperphysik und Werkstofforschung)
1991-01-01
Electrochemically deposited Fe(-Ni)-P alloys exhibit in the as-deposited state a strong magnetic anisotropy with the easy axis perpendicular to the foil plane. Using {sup 57}Fe Moessbauer measurements in three transmission directions and an evaluation procedure modified with respect to that reported previously, it is shown that the Fe{sub 43}Ni{sub 45}P{sub 12} alloy indeed possesses a pronounced normal orientation of the hyperfine field, i.e. the spontaneous magnetization. Application of an in-plane external field leads to an alignment of magnetic domains in field direction, whereas remanent-state results agree with those in the as-deposited state. (orig.).
P ,T -odd and magnetic hyperfine-interaction constants and excited-state lifetime for HfF+
Fleig, Timo
2017-10-01
Parity- and time-reversal-symmetry violating interaction constants required for the interpretation of a recent measurement [W. B. Cairncross et al., Phys. Rev. Lett. 119, 153001 (2017), 10.1103/PhysRevLett.119.153001] of corresponding symmetry violations in the Ω =1 (3Δ1) science state of the HfF+ molecular ion are reported. Using a relativistic four-component all-electron multireference configuration interaction model the nucleon-electron scalar-pseudoscalar interaction constant is determined as WS=20.0 [kHz]. An updated result for the electron electric-dipole-moment effective electric field of | Eeff|=22.7 [GV/cm ] is obtained. Further results of relevance in the context of the search for leptonic charge-parity violation such as the 177Hf magnetic hyperfine interaction constant and electronic G tensor for HfF+ are presented.
Hyperfine magnetic field on iron atoms as indication of stoichiometry in Co{sub 2}FeSi
Energy Technology Data Exchange (ETDEWEB)
Ksenofontov, Vadim; Balke, Benjamin; Felser, Claudia [Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg-University, Mainz (Germany); Wojcik, Marek [Institute of Physics, Polish Academy of Sciences, Warszawa (Poland); Wurmehl, Sabine [Department of Applied Physics, Physics of Nanostructures, Eindhoven University of Technology (Netherlands); Schneider, Horst; Jakob, Gerhard [Institute of Physics, Johannes Gutenberg University, Mainz (Germany)
2009-07-01
The Heusler compound Co{sub 2}FeSi is a promising half-metallic material for thin films spintronic applications. Among the factors reducing spin-polarization, the defects and antisite disordering in such materials play a crucial role. To clarify effects of the non-stoichiometry, the continuous series of model solid solutions Co{sub 3-x}Fe{sub x}Si (0.96
Hyperfine magnetic field on iron atoms and Co-Fe disordering in Co2FeSi
Ksenofontov, Vadim; Wójcik, Marek; Wurmehl, Sabine; Schneider, Horst; Balke, Benjamin; Jakob, Gerhard; Felser, Claudia
2010-05-01
The Heusler compound Co2FeSi is a prospective half-metallic material for spintronic applications. Defects and antisite disordering play a crucial role among the factors reducing spin polarization in such materials. To clarify effects of possible off-stoichiometry, a continuous series of model solid solutions Co3-xFexSi (0.6≤x≤1.4) was investigated by F57e Mössbauer spectroscopy and C59o nuclear magnetic resonance. It has been shown that the hyperfine magnetic fields on Fe can be used to monitor Co-Fe disordering in Co2FeSi-based bulk samples and thin films.
Intercalation effect on hyperfine parameters of Fe in FeSe superconductor with Tc = 42 K
Shylin, Sergii I.; Ksenofontov, Vadim; Sedlmaier, Stefan J.; Clarke, Simon J.; Cassidy, Simon J.; Wortmann, Gerhard; Medvedev, Sergey A.; Felser, Claudia
2015-03-01
57Fe-Mössbauer spectra of superconducting β-FeSe, the Li/NH3 intercalate product and a subsequent sample of this intercalate treated with moist He gas have been measured in the temperature range 4.7-290 K. A correlation is established between hyperfine parameters and critical temperature T{c} in these phases. A strong increase of the isomer shift upon intercalation is explained by a charge transfer from the Li/NH3 intercalate to the FeSe layers resulting in an increase of T{c} up to 42 K. A significant decrease of the quadrupole splitting above 240 K has been attributed to diffusive motion of Li+ ions within the interlamellar space.
Analysis of direct action fuzzy PID controller structures.
Mann, G I; Hu, B G; Gosine, R G
1999-01-01
The majority of the research work on fuzzy PID controllers focuses on the conventional two-input PI or PD type controller proposed by Mamdani (1974). However, fuzzy PID controller design is still a complex task due to the involvement of a large number of parameters in defining the fuzzy rule base. This paper investigates different fuzzy PID controller structures, including the Mamdani-type controller. By expressing the fuzzy rules in different forms, each PLD structure is distinctly identified. For purpose of analysis, a linear-like fuzzy controller is defined. A simple analytical procedure is developed to deduce the closed form solution for a three-input fuzzy inference. This solution is used to identify the fuzzy PID action of each structure type in the dissociated form. The solution for single-input-single-output nonlinear fuzzy inferences illustrates the effect of nonlinearity tuning. The design of a fuzzy PID controller is then treated as a two-level tuning problem. The first level tunes the nonlinear PID gains and the second level tunes the linear gains, including scale factors of fuzzy variables. By assigning a minimum number of rules to each type, the linear and nonlinear gains are deduced and explicitly presented. The tuning characteristics of different fuzzy PID structures are evaluated with respect to their functional behaviors. The rule decoupled and one-input rule structures proposed in this paper provide greater flexibility and better functional properties than the conventional fuzzy PHD structures.
The input-output relationship approach to structural identifiability analysis.
Bearup, Daniel J; Evans, Neil D; Chappell, Michael J
2013-02-01
Analysis of the identifiability of a given model system is an essential prerequisite to the determination of model parameters from physical data. However, the tools available for the analysis of non-linear systems can be limited both in applicability and by computational intractability for any but the simplest of models. The input-output relation of a model summarises the input-output structure of the whole system and as such provides the potential for an alternative approach to this analysis. However for this approach to be valid it is necessary to determine whether the monomials of a differential polynomial are linearly independent. A simple test for this property is presented in this work. The derivation and analysis of this relation can be implemented symbolically within Maple. These techniques are applied to analyse classical models from biomedical systems modelling and those of enzyme catalysed reaction schemes. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.
Semi-analytical postbuckling strength analysis of anisotropic shell structures
Brauns, J.; Skadins, U.
2017-10-01
An investigation of the forms of shell buckling has been the subject of many experimental and theoretical studies. On the basis of analysing of the forms of equilibrium it is possible to determine the stability of a structure as a whole, especially if a statistical analysis is used. The numerical analysis of the shells considered is based on a semi-analytical treatment of displacement and stress field. This method is proven for static and dynamic nonlinear analysis of general shells of revolution and leads to important advantages in efficiency and accuracy compared with a common finite element analysis, especially in the case of geometrically imperfect shells. The method developed permits determination of stresses in a shell by means of an experimental deflection function. Failure criterion allows predicting the sites of fracture and maintenance of a shell upon loss of stability.
Alexandrov, N N; Fischer, D
1996-07-01
We have developed a new method and program, SARF2, for fast comparison of protein structures, which can detect topological as well as nontopological similarities. The method searches for large ensembles of secondary structure elements, which are mutually compatible in two proteins. These ensembles consist of small fragments of C alpha-trace, similarly arranged in three-dimensional space in two proteins, but not necessarily equally-ordered along the polypeptide chains. The program SARF2 is available for everyone through the World-Wide Web (WWW). We have performed an exhaustive pairwise comparison of all the entries from a recent issue of the Protein Data Bank (PDB) and report here on the results of an automated hierarchical cluster analysis. In addition, we report on several new cases of significant structural resemblance between proteins. To this end, a new definition of the significance of structural similarity is introduced, which effectively distinguishes the biologically meaningful equivalences from those occurring by chance. Analyzing the distribution of sequence similarity in significant structural matches, we show that sequence similarity as low as 20% in structurally-prealigned proteins can be a strong indication for the biological relevance of structural similarity.
Geological-structural models used in SR 97. Uncertainty analysis
Energy Technology Data Exchange (ETDEWEB)
Saksa, P.; Nummela, J. [FINTACT Oy (Finland)
1998-10-01
The uncertainty of geological-structural models was studied for the three sites in SR 97, called Aberg, Beberg and Ceberg. The evaluation covered both regional and site scale models, the emphasis being placed on fracture zones in the site scale. Uncertainty is a natural feature of all geoscientific investigations. It originates from measurements (errors in data, sampling limitations, scale variation) and conceptualisation (structural geometries and properties, ambiguous geometric or parametric solutions) to name the major ones. The structures of A-, B- and Ceberg are fracture zones of varying types. No major differences in the conceptualisation between the sites were noted. One source of uncertainty in the site models is the non-existence of fracture and zone information in the scale from 10 to 300 - 1000 m. At Aberg the development of the regional model has been performed very thoroughly. At the site scale one major source of uncertainty is that a clear definition of the target area is missing. Structures encountered in the boreholes are well explained and an interdisciplinary approach in interpretation have taken place. Beberg and Ceberg regional models contain relatively large uncertainties due to the investigation methodology and experience available at that time. In site scale six additional structures were proposed both to Beberg and Ceberg to variant analysis of these sites. Both sites include uncertainty in the form of many non-interpreted fractured sections along the boreholes. Statistical analysis gives high occurrences of structures for all three sites: typically 20 - 30 structures/km{sup 3}. Aberg has highest structural frequency, Beberg comes next and Ceberg has the lowest. The borehole configuration, orientations and surveying goals were inspected to find whether preferences or factors causing bias were present. Data from Aberg supports the conclusion that Aespoe sub volume would be an anomalously fractured, tectonised unit of its own. This means that
Progress of structural genomics initiatives: an analysis of solved target structures.
Todd, Annabel E; Marsden, Russell L; Thornton, Janet M; Orengo, Christine A
2005-05-20
The explosion in gene sequence data and technological breakthroughs in protein structure determination inspired the launch of structural genomics (SG) initiatives. An often stated goal of structural genomics is the high-throughput structural characterisation of all protein sequence families, with the long-term hope of significantly impacting on the life sciences, biotechnology and drug discovery. Here, we present a comprehensive analysis of solved SG targets to assess progress of these initiatives. Eleven consortia have contributed 316 non-redundant entries and 323 protein chains to the Protein Data Bank (PDB), and 459 and 393 domains to the CATH and SCOP structure classifications, respectively. The quality and size of these proteins are comparable to those solved in traditional structural biology and, despite huge scope for duplicated efforts, only 14% of targets have a close homologue (>/=30% sequence identity) solved by another consortium. Analysis of CATH and SCOP revealed the significant contribution that structural genomics is making to the coverage of superfamilies and folds. A total of 67% of SG domains in CATH are unique, lacking an already characterised close homologue in the PDB, whereas only 21% of non-SG domains are unique. For 29% of domains, structure determination revealed a remote evolutionary relationship not apparent from sequence, and 19% and 11% contributed new superfamilies and folds. The secondary structure class, fold and superfamily distributions of this dataset reflect those of the genomes. The domains fall into 172 different folds and 259 superfamilies in CATH but the distribution is highly skewed. The most populous of these are those that recur most frequently in the genomes. Whilst 11% of superfamilies are bacteria-specific, most are common to all three superkingdoms of life and together the 316 PDB entries have provided new and reliable homology models for 9287 non-redundant gene sequences in 206 completely sequenced genomes. From the
Design-Oriented Analysis of Aircraft Fuselage Structures
Giles, Gary L.
1998-01-01
A design-oriented analysis capability for aircraft fuselage structures that utilizes equivalent plate methodology is described. This new capability is implemented as an addition to the existing wing analysis procedure in the Equivalent Laminated Plate Solution (ELAPS) computer code. The wing and fuselage analyses are combined to model entire airframes. The paper focuses on the fuselage model definition, the associated analytical formulation and the approach used to couple the wing and fuselage analyses. The modeling approach used to minimize the amount of preparation of input data by the user and to facilitate the making of design changes is described. The fuselage analysis is based on ring and shell equations but the procedure is formulated to be analogous to that used for plates in order to take advantage of the existing code in ELAPS. Connector springs are used to couple the wing and fuselage models. Typical fuselage analysis results are presented for two analytical models. Results for a ring-stiffened cylinder model are compared with results from conventional finite-element analyses to assess the accuracy of this new analysis capability. The connection of plate and ring segments is demonstrated using a second model that is representative of the wing structure for a channel-wing aircraft configuration.
Multiscale analysis of structure development in expanded starch snacks
van der Sman, R. G. M.; Broeze, J.
2014-11-01
In this paper we perform a multiscale analysis of the food structuring process of the expansion of starchy snack foods like keropok, which obtains a solid foam structure. In particular, we want to investigate the validity of the hypothesis of Kokini and coworkers, that expansion is optimal at the moisture content, where the glass transition and the boiling line intersect. In our analysis we make use of several tools, (1) time scale analysis from the field of physical transport phenomena, (2) the scale separation map (SSM) developed within a multiscale simulation framework of complex automata, (3) the supplemented state diagram (SSD), depicting phase transition and glass transition lines, and (4) a multiscale simulation model for the bubble expansion. Results of the time scale analysis are plotted in the SSD, and give insight into the dominant physical processes involved in expansion. Furthermore, the results of the time scale analysis are used to construct the SSM, which has aided us in the construction of the multiscale simulation model. Simulation results are plotted in the SSD. This clearly shows that the hypothesis of Kokini is qualitatively true, but has to be refined. Our results show that bubble expansion is optimal for moisture content, where the boiling line for gas pressure of 4 bars intersects the isoviscosity line of the critical viscosity 106 Pa.s, which runs parallel to the glass transition line.
Stress analysis for wall structure in mobile hot cell design
Energy Technology Data Exchange (ETDEWEB)
Bahrin, Muhammad Hannan, E-mail: hannan@nuclearmalaysia.gov.my; Rahman, Anwar Abdul, E-mail: anwar@nuclearmalaysia.gov.my; Hamzah, Mohd Arif, E-mail: arif@nuclearmalaysia.gov.my; Mamat, Mohd Rizal; Azman, Azraf; Hasan, Hasni [Prototype and Plant Development Centre, Technical Services Division, Malaysian Nuclear Agency (Malaysia)
2016-01-22
Malaysian Nuclear Agency is developing a Mobile Hot Cell (MHC) in order to handle and manage Spent High Activity Radioactive Sources (SHARS) such as teletherapy heads and irradiators. At present, there are only two units of MHC in the world, in South Africa and China. Malaysian Mobile Hot cell is developed by Malaysian Nuclear Agency with the assistance of IAEA expert, based on the design of South Africa and China, but with improved features. Stress analysis has been performed on the design in order to fulfil the safety requirement in operation of MHC. This paper discusses the loading analysis effect from the sand to the MHC wall structure.
Ulysses Data Analysis: Magnetic Topology of Heliospheric Structures
Crooker, Nancy
2001-01-01
In this final technical report on research funded by a NASA grant, a project overview is given by way of summaries on nine published papers. Research has included: 1) Using suprathermal electron data to study heliospheric magnetic structures; 2) Analysis of magnetic clouds, coronal mass ejections (CME), and the heliospheric current sheet (HCS); 3) Analysis of the corotating interaction region (CIR) which develop from interactions between solar wind streams of different velocities; 4) Use of Ulysses data in the interpretation of heliospheric events and phenomena.
Analysis of the Structure Ratios of the Funding Sources
Directory of Open Access Journals (Sweden)
Maria Daniela Bondoc
2014-06-01
Full Text Available The funding sources of the assets and liabilities in the balance sheet include equity capitals and the debts of the entity. The analysis of the structure rates of the funding sources allows for making assessments related to the funding policy, highlighting the financial autonomy and how resources are provided. Using the literature specializing in economic and financial analysis, this paper aims at presenting these rates that focus, on the one hand, to reflect the degree of financial dependence (the rate of financial stability, the rate of global financial autonomy, the rate of on-term financial autonomy and on the other hand the debt structure (the rate of short-term debts, the global indebtedness rate, the on-term indebtedness rate. Based on the financial statements of an entity in the Argeş County, I analysed these indicators, and I drew conclusions and made assessments related to the autonomy, indebtedness and financial stability of the studied entity.
Free vibration analysis of coupled fluid-structure systems
Gupta, K. K.
1982-01-01
An efficient numerical technique for the eigenvalue solution in the free vibration analysis of compressible fluid-structure coupled systems is presented. The fluid is assumed to be compressible in nature and the incompressible problem is only a special case of the present generalized algorithm. A natural frequency analysis of the structure in the absence of any fluid is achieved by a combined Sturm sequence and inverse iteration technique that computes only the required eigenvalues and vectors. A special inverse iteration scheme is then developed for the coupled system that uses the computed eigenvalues as starting iteration values for convergence. Numerical results obtained by solving a number of standard test cases indicate the pattern of root convergence corresponding to various simplifying assumptions.
Structural analysis of a ship on global aspect using ANSYS
Rahman, M. Muzibur; Kamol, Rajia Sultana; Islam, Reyana
2017-12-01
Ship is a complex geometry which undergoes a combination of loadings such as hydrostatic, hydrodynamic, wind, wave etc. at sea and thus adequate strength in a ship has always been one of the most challenging tasks for the ship designers. International Maritime Organization (IMO) and classification societies are providing the standards to ensure the adequacy of strength for the ship against all demands throughout its service life. Thus, structural analysis is needed to assess the overall strength of hull, and the means in this regard are based on finite element method which may be applied either local or global aspect of the ship. This paper is an attempt to carry out the structural analysis of a ship in global aspect using ANSYS software to locate the most stress concentration and deformed area, which will have ultimate effect on fatigue fracture.
D2 Delta Robot Structural Design and Kinematics Analysis
Yang, Xudong; wang, Song; Dong, Yu; Yang, Hai
2017-12-01
In this paper, a new type of Delta robot with only two degrees of freedom is proposed on the basis of multi - degree - of - freedom delta robot. In order to meet our application requirements, we have carried out structural design and analysis of the robot. Through SolidWorks modeling, combined with 3D printing technology to determine the final robot structure. In order to achieve the precise control of the robot, the kinematics analysis of the robot was carried out. The SimMechanics toolbox of MATLAB is used to establish the mechanism model, and the kinematics mathematical model is used to simulate the robot motion control in Matlab environment. Finally, according to the design mechanism, the working space of the robot is drawn by the graphic method, which lays the foundation for the motion control of the subsequent robot.
Structure analysis of growing network based on partial differential equations
Directory of Open Access Journals (Sweden)
Junbo JIA
2016-04-01
Full Text Available The topological structure is one of the most important contents in the complex network research. Therein the node degree and the degree distribution are the most basic characteristic quantities to describe topological structure. In order to calculate the degree distribution, first of all, the node degree is considered as a continuous variable. Then, according to the Markov Property of growing network, the cumulative distribution function's evolution equation with time can be obtained. Finally, the partial differential equation (PDE model can be established through distortion processing. Taking the growing network with preferential and random attachment mechanism as an example, the PDE model is obtained. The analytic expression of degree distribution is obtained when this model is solved. Besides, the degree function over time is the same as the characteristic line of PDE. At last, the model is simulated. This PDE method of changing the degree distribution calculation into problem of solving PDE makes the structure analysis more accurate.
Analysis of local influences in structural details of the bridges
Directory of Open Access Journals (Sweden)
Adam RUDZIK
2015-03-01
Full Text Available The article analyses the problems of local influences in structural details of bridges as the critical locations, whose damages or excessive force may directly affect the safety of users. These analyses are shown on selected examples. Presented is the example of local changes in the forms of proper vibrations in the node of the truss bridge that can be used in expert issues concerning the causes of damages. The second example are the changes in stresses in the stay cable anchorage element including the nonlinear material models. Models of this type can be successfully used by engineers as they allow for analysis of selected structural details without the need for detailed mapping of the entire structure, but only a selected section.
Structural Analysis of Grounding Damages on MS DEXTRA
DEFF Research Database (Denmark)
Pedersen, Preben Terndrup; Simonsen, Bo Cerup; Zhang, Shengming
with internal and external collision dynamics and the present report which deals with structural analysis of grounding events.The first part of the present report is devoted to an energy balance for raking damage situations.Then follows a numerical study of the forces associated with cutting and crushing...... of the bottom of MS DEXTRA and other RoRo vessels.Key words: ship grounding, inner mechanics, structural damage, absorbed energy, bottom damage distribution, and Minorsky method.......Sub-task 1.2 of DEXTREMEL deals with development of models for external ship collision and grounding dynamics and for internal ship structure dynamics. In order to get a better overview of the work performed in this task it has been decided to write two reports on the work. One dealing...
Mechanical Properties for Reliability Analysis of Structures in Glassy Carbon
Garion, Cédric
2014-01-01
Despite its good physical properties, the glassy carbon material is not widely used, especially for structural applications. Nevertheless, its transparency to particles and temperature resistance are interesting properties for the applications to vacuum chambers and components in high energy physics. For example, it has been proposed for fast shutter valve in particle accelerator [1] [2]. The mechanical properties have to be carefully determined to assess the reliability of structures in such a material. In this paper, mechanical tests have been carried out to determine the elastic parameters, the strength and toughness on commercial grades. A statistical approach, based on the Weibull’s distribution, is used to characterize the material both in tension and compression. The results are compared to the literature and the difference of properties for these two loading cases is shown. Based on a Finite Element analysis, a statistical approach is applied to define the reliability of a structural component in gl...
Structural Analysis of Protein Complexes by Cryo Electron Microscopy.
Costa, Tiago R D; Ignatiou, Athanasios; Orlova, Elena V
2017-01-01
Structural studies of biocomplexes using single-particle cryo-electron microscopy (cryo-EM) is now a well-established technique in structural biology and has become competitive with X-ray crystallography. The latest advances in EM enable us to determine structures of protein complexes at 3-5 Å resolution for an extremely broad range of sizes from ~200 kDa up to hundreds of megadaltons (Bartesaghi et al., Science 348(6239):1147-1151, 2051; Bai et al., Nature 525(7568):212-217, 2015; Vinothkumar et al., Nature 515(7525):80-84, 2014; Grigorieff and Harrison, Curr Opin Struct Biol 21(2):265-273, 2011). The majority of biocomplexes comprise a number of different components and are not amenable to crystallisation. Secretion systems are typical examples of such multi-protein complexes, and structural studies of them are extremely challenging. The only feasible approach to revealing their spatial organisation and functional modification is cryo-EM. The development of systems for digital registration of images and algorithms for the fast and efficient processing of recorded images and subsequent analysis facilitated the determination of structures at near-atomic resolution. In this review we will describe sample preparation for cryo-EM, how data are collected by new detectors, and the logistics of image analysis through the basic steps required for reconstructions of both small and large biological complexes and their refinement to nearly atomic resolution. The processing workflow is illustrated using examples of EM analysis of a Type IV Secretion System.
Directory of Open Access Journals (Sweden)
Chi-Seung Lee
2012-06-01
Full Text Available In the present study, the structural response of breakwaters installed on container carriers against green water impact loads was numerically investigated on the basis of the fluid-structure interaction analysis. A series of numerical studies is carried out to induce breakwater collapse under such conditions, whereby a widely accepted fluid-structure interaction analysis technique is adopted to realistically consider the phenomenon of green water impact loads. In addition, the structural behaviour of these breakwaters under green water impact loads is investigated simultaneously throughout the transient analysis. A verification study of the numerical results is performed using data from actual collapse incidents of breakwaters on container carriers. On the basis of the results of a series of numerical analyses, the pressure distribution of green water was accurately predicted with respect to wave mass and velocity. It is expected that the proposed analytical methodology and predicted pressure distribution could be used as a practical guideline for the design of breakwaters on container carriers.
Energy Technology Data Exchange (ETDEWEB)
Hubin, Elizabeth A.; Lilic, Mirjana; Darst, Seth A.; Campbell, Elizabeth A.
2017-07-13
The mycobacteria RNA polymerase (RNAP) is a target for antimicrobials against tuberculosis, motivating structure/function studies. Here we report a 3.2 Å-resolution crystal structure of a Mycobacterium smegmatis (Msm) open promoter complex (RPo), along with structural analysis of the Msm RPo and a previously reported 2.76 Å-resolution crystal structure of an Msm transcription initiation complex with a promoter DNA fragment. We observe the interaction of the Msm RNAP α-subunit C-terminal domain (αCTD) with DNA, and we provide evidence that the αCTD may play a role in Mtb transcription regulation. Our results reveal the structure of an Actinobacteria-unique insert of the RNAP β' subunit. Finally, our analysis reveals the disposition of the N-terminal segment of Msm σA, which may comprise an intrinsically disordered protein domain unique to mycobacteria. The clade-specific features of the mycobacteria RNAP provide clues to the profound instability of mycobacteria RPo compared with E. coli.
Quantitative assessment of gastric atrophy using the syntactic structure analysis.
Zaitoun, A M; al Mardini, H; Record, C O
1998-12-01
To assess the topographical relation between gastric glands, using the minimum spanning tree (MST), to derive both a model of neighbourhood and quantitative representation of the tissue's architecture, to assess the characteristic features of gastric atrophy, and to assess the grades of gastric atrophy. Haematoxylin and eosin stained sections from corporal and antral biopsy specimens (n = 139) from normal patients and from patients with nonatrophic gastritis and atrophic gastritis of grades 1, 2, and 3 (Sydney system) were assessed by image analysis system (Prodit 5.2) and 11 syntactic structure features were derived. These included both line and connectivity features. Syntactic structure analysis was correlated with the semiquantitative grading system of gastric atrophy. The study showed significant reductions in the number of points and the length of MST in both body and antrum. The standard deviation of the length of MST was significantly increased in all grades of atrophy. The connectivity to two glands was the highest and most affected by the increased grade of atrophy. The reciprocal values of the Wiener, Randic, and Balaban indices showed significant changes in the volume of gland, abnormality in the shape of glands, and changes in irregularity and branching of the glands in both types of gastric mucosa. There was a complete separation in the MST, connectivity, and index values between low grade and high grade gastric atrophy. (1) Gastric atrophy was characterised by loss of the gland, variation in the volume, reduction in the neighbourhood, irregularity in spacing, and abnormality in the shape of the glands. (2) Syntactic structure analysis significantly differentiated minor changes in gastric gland (low grade atrophy) from high grade atrophy of clinical significance. (3) Syntactic structure analysis is a simple, fast, and highly reproducible technique and appears a promising method for quantitative assessment of atrophy.
Thermal analysis of a hypersonic wing test structure
Sandlin, Doral R.; Swanson, Neil J., Jr.
1989-01-01
The three-dimensional finite element modeling techniques developed for the thermal analysis of a hypersonic wing test structure (HWTS) are described. The computed results are compared to measured test data. In addition, the results of a NASA two-dimensional parameter finite difference local thermal model and the results of a contractor two-dimensional lumped parameter finite difference local thermal model will be presented.
Thermal and structural analysis of a filter vessel ceramic tubesheet
Energy Technology Data Exchange (ETDEWEB)
Mallett, R.H. [Mallett Technology, Inc., Research Triangle Park, NC (United States); Swindeman, R.W. [Oak Ridge National Lab., TN (United States); Zievers, J.F. [Industrial Filter & Pump Mfg. Co., Cicero, IL (United States)
1995-08-01
A ceramic tubesheet assembly for a hot gas filter vessel is analyzed using the finite element method to determine stresses under differential pressure loading. The stresses include local concentration effects. Selection of the stress measures for evaluation of structural integrity is discussed. Specification of stress limits based upon limited data is considered. Stress results from this ongoing design analysis technology project are shown for one design concept.
Dynamic response analysis of a 24-story damped steel structure
Feng, Demin; Miyama, Takafumi
2017-10-01
In Japanese and Chinese building codes, a two-stage design philosophy, damage limitation (small earthquake, Level 1) and life safety (extreme large earthquake, Level 2), is adopted. It is very interesting to compare the design method of a damped structure based on the two building codes. In the Chinese code, in order to be consistent with the conventional seismic design method, the damped structure is also designed at the small earthquake level. The effect of damper systems is considered by the additional damping ratio concept. The design force will be obtained from the damped design spectrum considering the reduction due to the additional damping ratio. The additional damping ratio by the damper system is usually calculated by a time history analysis method at the small earthquake level. The velocity dependent type dampers such as viscous dampers can function well even in the small earthquake level. But, if steel damper is used, which usually remains elastic in the small earthquake, there will be no additional damping ratio achieved. On the other hand, a time history analysis is used in Japan both for small earthquake and extreme large earthquake level. The characteristics of damper system and ductility of the structure can be modelled well. An existing 24-story steel frame is modified to demonstrate the design process of the damped structure based on the two building codes. Viscous wall type damper and low yield steel panel dampers are studied as the damper system.