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Sample records for octupole deformation properties

  1. Octupole deformation properties of the Barcelona-Catania-Paris energy density functionals

    International Nuclear Information System (INIS)

    We discuss the octupole deformation properties of the recently proposed Barcelona-Catania-Paris (BCP) energy density functionals for two sets of isotopes, those of radium and barium, in which it is believed that octupole deformation plays a role in the description of the ground state. The analysis is carried out in the mean field framework (Hartree-Fock-Bogoliubov approximation) by using the axially symmetric octupole moment as a constraint. The main ingredients entering the octupole collective Hamiltonian are evaluated and the lowest-lying octupole eigenstates are obtained. In this way we restore, in an approximate way, the parity symmetry spontaneously broken by the mean field and also incorporate octupole fluctuations around the ground-state solution. For each isotope the energy of the lowest lying 1- state and the B(E1) and B(E3) transition probabilities have been computed and compared to both the experimental data and the results obtained in the same framework with the Gogny D1S interaction, which are used here as a well-established benchmark. Finally, the octupolarity of the configurations involved in the way down to fission of 240Pu, which is strongly connected to the asymmetric fragment mass distribution, is studied. We confirm with this thorough study the suitability of the BCP functionals to describe octupole-related phenomena.

  2. Octupole deformation properties of the Barcelona-Catania-Paris energy density functionals

    CERN Document Server

    Robledo, L M; Schuck, P; Viñas, X

    2010-01-01

    We discuss the octupole deformation properties of the recently proposed Barcelona-Catania-Paris (BCP) energy density functionals for two sets of isotopes, those of radium and barium, where it is believed that octupole deformation plays a role in the description of the ground state. The analysis is carried out in the mean field framework (Hartree- Fock- Bogoliubov approximation) by using the axially symmetric octupole moment as a constraint. The main ingredients entering the octupole collective Hamiltonian are evaluated and the lowest lying octupole eigenstates are obtained. In this way we restore, in an approximate way, the parity symmetry spontaneously broken by the mean field and also incorporate octupole fluctuations around the ground state solution. For each isotope the energy of the lowest lying $1^{-}$state and the $B(E1)$ and $B(E3)$ transition probabilities have been computed and compared to both the experimental data and the results obtained in the same framework with the Gogny D1S interaction, which...

  3. Alignment effects and stable octupole deformation in the actinides

    International Nuclear Information System (INIS)

    Explicit relations between the alignment of the intrinsic octupole momentum and a new type of deformation which does not conserve the axial symmetry are established. It seems that such an octupole deformation of the nuclear shape is indeed a general property of nuclear high spin states, whatever may become the axial octupole shape with increasing rotational frequency. However the nature seems to be reticent to show such properties easily and fortunately there exists shell-effects which allow to study them at low spin but only in some exceptional cases. One should push forwards both theory and experiments in this field. From the experimental point of view, one may expect much from the new multidetection techniques although one must overcome the experimental difficulties arising from the high rate of fission products in the (HI, xn) reactions

  4. Octupole Deformed Nuclei in the Actinide Region

    CERN Multimedia

    Thorsteinsen, T; Rubio barroso, B; Simpson, J; Gulda, K; Sanchez-vega, M; Cocks, J; Nybo, K; Garcia borge, M; Aas, A; Fogelberg, B; Honsi, J; Smith, G; Naumann, R; Grant, I

    2002-01-01

    % IS322 \\\\ \\\\ The aim of the present study is to investigate the limits of the "island" of octupole deformation in the mass region A=225. It is of particular importance to demonstrate experimentally the sudden disappearance of the stable octupole deformation in the presence of a well developed quadrupole field. \\\\ \\\\In order to establish the upper border line the $\\beta$ decay chains of $^{227}$Rn $\\rightarrow ^{227}$Fr $\\rightarrow ^{227}$Ra and $^{231}$Fr $\\rightarrow ^{231}$Ra $\\rightarrow ^{231}$Ac were studied at PSB-ISOLDE using advanced fast timing and $\\gamma$-ray spectroscopy techniques. The lifetimes of the excited states have been measured in the picosecond range using the time-delayed $\\beta\\gamma\\gamma$(t) method.

  5. Chaos in axially symmetric potentials with octupole deformation

    Energy Technology Data Exchange (ETDEWEB)

    Heiss, W.D.; Nazmitdinov, R.G.; Radu, S. (Centre for Nonlinear Studies and Department of Physics, University of Witwatersrand, PO Wits 2050, Johannesburg (South Africa) Departamento de Fisica Teorica C-XI, Universidad Autonoma de Madrid, E-28049, Madrid (Spain))

    1994-04-11

    Classical and quantum mechanical results are reported for the single particle motion in a harmonic oscillator potential which is characterized by a quadrupole deformation and an additional octupole deformation. The chaotic character of the motion is strongly dependent on the quadrupole deformation in that for a prolate deformation virtually no chaos is discernible while for the oblate case the motion shows strong chaos when the octupole term is turned on.

  6. Chaos in axially symmetric potentials with octupole deformation

    CERN Document Server

    Heiss, W D; Radu, S; Rashid G Nazmitdinov; Stefanel Radu

    1994-01-01

    Classical and quantum mechanical results are reported for the single particle motion in a harmonic oscillator potential which is characterized by a quadrupole deformation and an additional octupole deformation. The chaotic character of the motion is srongly dependent on the quadrupole deformation in that for a prolate deformation virtually no chaos is discernible while for the oblate case the motion shows strong chaos when the octupole term is turned on.

  7. Chaos in Axially Symmetric Potentials with Octupole Deformation

    OpenAIRE

    Heiss, W. Dieter; Nazmitdinov, Rashid G.; Radu, Stefanel

    1994-01-01

    Classical and quantum mechanical results are reported for the single particle motion in a harmonic oscillator potential which is characterized by a quadrupole deformation and an additional octupole deformation. The chaotic character of the motion is srongly dependent on the quadrupole deformation in that for a prolate deformation virtually no chaos is discernible while for the oblate case the motion shows strong chaos when the octupole term is turned on.

  8. Chaos in axially symmetric potentials with octupole deformation

    International Nuclear Information System (INIS)

    Classical and quantum mechanical results are reported for the single particle motion in a harmonic oscillator potential which is characterized by a quadrupole deformation and an additional octupole deformation. The chaotic character of the motion is strongly dependent on the quadrupole deformation in that for a prolate deformation virtually no chaos is discernible while for the oblate case the motion shows strong chaos when the octupole term is turned on

  9. Octupole deformation in light actinides within an analytic quadrupole octupole axially symmetric model with Davidson potential

    CERN Document Server

    Bonatsos, Dennis; Minkov, N; Karampagia, S; Petrellis, D

    2015-01-01

    The analytic quadrupole octupole axially symmetric model, which had successfully predicted 226Ra and 226Th as lying at the border between the regions of octupole deformation and octupole vibrations in the light actinides using an infinite well potential (AQOA-IW), is made applicable to a wider region of nuclei exhibiting octupole deformation, through the use of a Davidson potential (AQOA-D). Analytic expressions for energy spectra and B(E1), B(E2), B(E3) transition rates are derived. The spectra of 222-226Ra and 224,226Th are described in terms of the two parameters phi_0 (expressing the relative amount of octupole vs. quadrupole deformation) and beta_0 (the position of the minimum of the Davidson potential), while the recently determined B(EL) transition rates of 224Ra, presenting stable octupole deformation, are successfully reproduced. A procedure for gradually determining the parameters appearing in the B(EL) transitions from a minimum set of data, thus increasing the predictive power of the model, is out...

  10. Periodic Orbits and Shell Structure in Octupole Deformed Potentials

    OpenAIRE

    Heiss, W. Dieter; Nazmitdinov, Rashid G.; Radu, Stefanel

    1994-01-01

    The effect of an octupole term in a quadrupole deformed single particle potential is studied from the classical and quantum mechanical view point. Whereas the problem is nonintegrable, the quantum mechanical spectrum nevertheless shows some shell structure in the superdeformed prolate case for particular, yet fairly large octupole strengths; for spherical or oblate deformation the shell structure disappears. This result is associated with classical periodic orbits which are ...

  11. The multiphonon method as a dynamical approach to octupole correlations in deformed nuclei

    International Nuclear Information System (INIS)

    The octupole correlations in nuclei are studied within the framework of the multiphonon method which is mainly the exact diagonalization of the total Hamiltonian in the space spanned by collective phonons. This treatment takes properly into account the Pauli principle. It is a microscopic approach based on a reflection symmetry of the potential. The spectroscopic properties of double even and odd-mass nuclei are nicely reproduced. The multiphonon method appears as a dynamical approach to octupole correlations in nuclei which can be compared to other models based on stable octupole deformation. 66 refs

  12. Experimental tests for stable octupole deformation in actinium-227

    International Nuclear Information System (INIS)

    The question of intrinsic reflection asymmetry or stable-octupole deformation in 227Ac was studied by the single-proton stripping reactions 226Ra(3He,d)227Ac with E/sub 3He/ = 30 MeV and 226Ra(?,t)227Ac with E/sub ?/ = 30 MeV and by measuring the magnetic moment of the first excited 3/2+ state at 27.38 keV by a differential perturbed angular correlation (DPAC) experiment. Theoretical differential cross sections were determined using calculated nuclear structure factors with and without octupole-deformed Woods-Saxon model wave functions. Theoretical values for the magnetic moments of the ground state and first excited state with and without octupole deformation were determined using calculated intrinsic g-factors from folded Yukawa model wave functions. The results of the proton-stripping cross sections are inconclusive. No how comparison of the measured values for the magnetic moment of the first excited state with a previous measurement for the ground state seems to support stable octupole deformation in 227Ac. Therefore, the energy ordering of orbitals and the magnetic moment results are consistent and they seem to support a stable-octupole deformed shape for the ground state parity doublet in 227Ac. Furthermore, the results are consistent with the branching ratio determination of the magnetic moment of the first excited state in 227Ac which is in agreement with the stable-octupole model prediction

  13. Periodic orbits and shell structure in octupole deformed potentials

    CERN Document Server

    Dieter, W R; Radu, S; Dieter, W; Nazmitdinov, Rashid G; Radu, Stefanel

    1994-01-01

    The effect of an octupole term in a quadrupole deformed single particle potential is studied from the classical and quantum mechanical view point. Whereas the problem is nonintegrable, the quantum mechanical spectrum nevertheless shows some shell structure in the superdeformed prolate case for particular, yet fairly large octupole strengths; for spherical or oblate deformation the shell structure disappears. This result is associated with classical periodic orbits which are found by employing the removal of resonances method; this approximation method allows determination of the shape of the orbit and of the approximate octupole coupling strength for which it occurs. The validity of the method is confirmed by solving numerically the classical equations of motion. The quantum mechanical shell structure is analysed using the particle number dependence of the fluctuating part of the total energy. In accordance with the classical result this dependence turns out to be very similar for a superdeformed prolate pote...

  14. Periodic orbits and shell structure in octupole deformed potentials

    Energy Technology Data Exchange (ETDEWEB)

    Heiss, W.D. (Centre for Nonlinear Studies and Department of Physics, University of the Witwatersrand, P.O. Wits 2050, Johannesburg (South Africa)); Nazmitdinov, R.G. (Departamento de Fisica Teorica C-XI, Universidad Autonoma de Madrid, E-28049 Madrid (Spain)); Radu, S. (Centre for Nonlinear Studies and Department of Physics, University of the Witwatersrand, P.O. Wits 2050, Johannesburg (South Africa))

    1995-01-15

    The effect of an octupole term in a quadrupole deformed single-particle potential is studied from the classical and quantum-mechanical viewpoint. Whereas the problem is nonintegrable, the quantum-mechanical spectrum nevertheless shows some shell structure in the superdeformed prolate case for particular, yet fairly large octupole strengths; for spherical or oblate deformation the shell structure disappears. This result is associated with classical periodic orbits that are found by employing the removal of resonances method; this approximation method allows determination of the shape of the orbit and of the approximate octupole coupling strength for which it occurs. The validity of the method is confirmed by solving numerically the classical equations of motion. The quantum-mechanical shell structure is analyzed using the particle-number dependence of the fluctuating part of the total energy. In accordance with the classical result, this dependence turns out to be very similar for a superdeformed prolate potential plus octupole term and a hyperdeformed prolate potential without octupole term. In this way the shell structure is explained at least for some few hundred levels. The Fourier transform of the level density further corroborates these findings.

  15. Periodic orbits and shell structure in octupole deformed potentials

    International Nuclear Information System (INIS)

    The effect of an octupole term in a quadrupole deformed single-particle potential is studied from the classical and quantum-mechanical viewpoint. Whereas the problem is nonintegrable, the quantum-mechanical spectrum nevertheless shows some shell structure in the superdeformed prolate case for particular, yet fairly large octupole strengths; for spherical or oblate deformation the shell structure disappears. This result is associated with classical periodic orbits that are found by employing the removal of resonances method; this approximation method allows determination of the shape of the orbit and of the approximate octupole coupling strength for which it occurs. The validity of the method is confirmed by solving numerically the classical equations of motion. The quantum-mechanical shell structure is analyzed using the particle-number dependence of the fluctuating part of the total energy. In accordance with the classical result, this dependence turns out to be very similar for a superdeformed prolate potential plus octupole term and a hyperdeformed prolate potential without octupole term. In this way the shell structure is explained at least for some few hundred levels. The Fourier transform of the level density further corroborates these findings

  16. Tri-axial Octupole Deformations and Shell Structure

    OpenAIRE

    Heiss, W. D.; Nazmitdinov, R. G.; Lynch, R. A.

    1999-01-01

    Manifestations of pronounced shell effects are discovered when adding nonaxial octupole deformations to a harmonic oscillator model. The degeneracies of the quantum spectra are in a good agreement with the corresponding main periodic orbits and winding number ratios which are found by classical analysis.

  17. Studies of Stable Octupole Deformations in the Radium Region

    CERN Multimedia

    2002-01-01

    The purpose of the present project is to locate and identify states in the atomic nuclei possessing stable pearshaped octupole deformation. Such states, formally related to the structures known in molecular physics, manifest themselves as families of parity doublets in odd nuclei.\\\\ \\\\ The best possibilities for observing stable octupole deformations are offered in the Ra-region. Both theoretical calculations and experimental indications support such expectations. Such indications are the non-observation of two-phonon octupole vibrational states in the ISOLDE studies of the even-even radium nuclei, and the reversed sign of the decoupling factor of the ground state band in |2|2|5Ra observed in the single-neutron transfer reactions. In order to establish the predicted strong E1 and E3-transitions between the parity doublets in odd nuclei with stable octupole deformations it is proposed to study conversion electrons in odd-mass francium radium and radon isotopes following the @b-decay of francium and astatine. \\...

  18. Influence of the octupole mode on nuclear high-K isomeric properties

    Science.gov (United States)

    Minkov, Nikolay; Walker, Phil

    2014-05-01

    The influence of quadrupole-octupole deformations on the energy and magnetic properties of high-K isomeric states in even-even actinide (U, Pu, Cm, Fm, No), rare-earth (Nd, Sm and Gd), and superheavy (^{270}\\text{Ds}) nuclei is examined within a deformed shell model with pairing interaction. The neutron two-quasiparticle (2qp) isomeric energies and magnetic dipole moments are calculated over a wide range in the plane of quadrupole and octupole deformations. In most cases the magnetic moments exhibit a pronounced sensitivity to the octupole deformation. At the same time, the calculations outline three different groups of nuclei: with pronounced, shallow, and missing minima in the 2qp energy surfaces with respect to the octupole deformation. The result indicates regions of nuclei with octupole softness as well as with possible octupole deformation in the high-K isomeric states. These findings show the need for further theoretical analysis as well as of detailed experimental measurements of magnetic moments in heavy deformed nuclei.

  19. Search for stable octupole deformation in $^{225}$Fr

    CERN Document Server

    Burke, D G; Løvhøiden, G; García-Borge, M J; Cronqvist, M; Gabelmann, H; Gietz, H; Hill, P; Kaffrell, N; Mattsson, S; Naumann, R A; Nybø, K; Nyman, G H; Rogowski, J; Struble, G L; Thorsteinsen, T F

    1997-01-01

    Levels in $^{225}$Fr have been studied by $\\gamma$-ray and conversion-electron spectroscopy following the $\\beta$-decay of $^{225}$Rn, and by the $^{226}$Ra(t,$\\alpha$)$^{225}$Fr single-proton-pickup reaction. Multipolarities were obtained for $\\sim$ 50 $\\gamma$-transitions, and a level scheme was established in which definite spin-parity values were determined for over 20 of the 48 levels. Although low-lying rotational bands of both parities exist for $K=1/2$ and $K=3/2$, there is no experimental evidence to claim these are parity doublets. E1 strengths connecting the $K^\\pi=3/2^\\pm$ bands are intermediate between those for nuclides which are reflection symmetric and those claimed to be octupole deformed. The (t $\\alpha$) cross-sections are in better agreement with those predicted for the reflection-symmetric case than with those from an octupole-deformed description. These observations may be confirming theoretical predictions that octupole correlations are important in $^{225}$Fr, but that there is no larg...

  20. Octupole deformation in 149,151Sm nuclei

    International Nuclear Information System (INIS)

    Parity doublet states and alternating parity bands in 149,151Sm nuclei observed in 148,150Nd (?,3n?) reactions at E?=37 and 35 MeV are presented here. Nineteen new transitions in 149Sm and sixteen in 151Sm have been observed in singles and ?-?-t-r.f. coincidence experiments. Four alternating parity bands in 149Sm and two in 151Sm characterized by simplex quantum numbers are reported. The observed level schemes are interpreted in terms of octupole deformation. The energy difference due to parity splitting, collective rotational parameters, quasiparticle Routhians, single particle angular momentum alignments of bands with simplex quantum number s=±i in 149Sm and with s=-i in 151Sm have been calculated from the experimental results. From the E1, E2 branching ratios, the electric dipole moments are deduced to be left-angle D0 right-angle=0.19±0.08 e fm for 149Sm and left-angle D0 right-angle=0.36±0.11 e fm for 151Sm. The parameter C1, a function of the symmetry energy coefficient, has been estimated for 149Sm from the liquid drop model of Strutinsky for deformed nucleus, and has been found to be C1=0.002003-0.000159+0.000087 fm

  1. Octupole deformations in actinides at high spins within the cranking Skyrme-Hartree-Fock approach

    CERN Document Server

    Tsvetkov, A A; Nazmitdinov, R G

    2002-01-01

    The cranked Skyrme III effective Hamiltonian is applied for the analysis of the rotational dependence of the quadrupole and octupole moments in Ra, Th and U isotopes. A comparison of the intrinsic electric dipole moments calculated in the model with available experimental and theoretical values is presented. It is found that the non-axial octupole deformation Y_{32} becomes favorable at high spins for the actinide nuclei.

  2. Octupole deformations in actinides at high spins within the cranking Skyrme-Hartree-Fock approach

    Energy Technology Data Exchange (ETDEWEB)

    Tsvetkov, A.; Kvasil, J. [Particle and Nuclear Physics Institute, Charles University, Prague (Czech Republic); Nazmitdinov, R.G. [Max-Planck-Institut fuer Physik komplexer Systeme, Dresden (Germany); Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Dubna (Russian Federation)

    2002-08-01

    The cranked Skyrme III effective Hamiltonian is applied for the analysis of the rotational dependence of the quadrupole and octupole moments in Ra, Th and U isotopes. A comparison of the intrinsic electric dipole moments calculated in the model with available experimental and theoretical values is presented. It is found that the non-axial octupole deformation Y{sub 32} becomes favourable at high spins for the actinide nuclei. (author)

  3. Octupole deformations in actinides at high spins within the cranking Skyrme-Hartree-Fock approach

    International Nuclear Information System (INIS)

    The cranked Skyrme III effective Hamiltonian is applied for the analysis of the rotational dependence of the quadrupole and octupole moments in Ra, Th and U isotopes. A comparison of the intrinsic electric dipole moments calculated in the model with available experimental and theoretical values is presented. It is found that the non-axial octupole deformation Y32 becomes favourable at high spins for the actinide nuclei. (author)

  4. Octupole deformations in actinides at high spins within the cranking Skyrme-Hartree-Fock approach

    OpenAIRE

    Tsvetkov, A.; Kvasil, J.; Nazmitdinov, R. G.

    2000-01-01

    The cranked Skyrme III effective Hamiltonian is applied for the analysis of the rotational dependence of the quadrupole and octupole moments in Ra, Th, and U isotopes. A comparison of the intrinsic electric dipole moments calculated in the model with available experimental and theoretical values is presented. It is found that the non-axial octupole deformation $Y_{32}$ becomes favorable at high spins for the actinide nuclei.

  5. Collective models for quadrupole and octupole degrees of freedom and complex nuclear deformations

    International Nuclear Information System (INIS)

    We review current advances in the theoretical study of nuclear quadrupole and octupole collectivity and complex shape deformations. We present a collective model formalism which consistently describes the strong parity shift effect observed in low-lying spectra of nuclei with octupole deformations together with the fine rotational band structure developed at higher angular momenta. The parity effect is obtained by the Schroedinger equation for oscillations of the reflection asymmetric (octupole) shape between two opposite orientations in an angular momentum dependent double-well potential. The rotational structure is obtained by the collective quadrupole-octupole rotation Hamiltonian (QORM). The unified model scheme reproduces the complicated beat staggering patterns observed in the octupole bands of light actinide nuclei. It explains the angular momentum evolution of octupole spectra as the interplay between the octupole shape oscillation (parity shift) mode and the stable quadrupole-octupole rotation mode. We also discuss an analytic collective model in which the relative presence of the quadrupole and octupole deformations is determined by a parameter (?0), while axial symmetry is obeyed. The model, called the Analytic Quadrupole Octupole Axially Symmetric model (AQOA), involves an infinite well potential, provides predictions for energy and B(EL) ratios which depend only on (?0), draws the border between the regions of octupole deformation and octupole vibrations in an essentially parameter-independent way, and describes well 226Th and 226Ra, for which experimental energy data are shown to suggest that they lie close to this border. The similarity of the AQOA results with ?0=450 for ground state band spectra and B(E2) transition rates to the predictions of the X(5) model is pointed out. Analytic solutions are also obtained for Davidson potentials of the form ?2+?4/?2, leading to the AQOA spectrum through a variational procedure. Also, we present results of a recent model study of the rotation-vibration motion of nuclei in which the axial quadrupole and octupole degrees of freedom are coupled through the centrifugal interaction. The collective potential depends on the two deformation variables ?2 and ?3 as well as on the angular momentum. In the limit of a frozen ?2 the system oscillates between positive and negative octupole deformations by tunnelling through the barrier of the double-well potential in ?3. When ?2 is let to vary, the system oscillates between the positive and negative ?3-values by rounding the barrier in the (?2, ?3 )- plane, instead of tunnelling. We examine the consequence of the 'rounding' in the cases when: i) the potential minima increase with the angular momentum I, and ii) the minima do not change with I. In the first case the spectrum of the system is characterized by a parity shift effect which decreases with the increase of I, while in the second case a constant parity shift is obtained. This result outlines a general framework for the evolution of nuclear collectivity in the regions where octupole vibrations and octupole deformations are observed

  6. Microscopic description of collective states near the yrast line of nuclei with stable octupole deformation

    Energy Technology Data Exchange (ETDEWEB)

    Kvasil, J.; Nazmitdinov, R.G. (Joint Inst. for Nuclear Research, Dubna (USSR). Lab. of Theoretical Physics)

    1985-06-03

    Collective states near the yrast line in nuclei with stable octupole deformation are discussed in the framework of the random phase approximation (RPA) based on the cranking model. These vibrational states are characterized by the quantum number of generalized signature (eigenvalue of the operator Ssub(x) = PRsub(x)/sup -1/(..pi..)). In the zero-octupole deformation limit the RPA equations of motion are reduced to the well-known ones characterized by both values of parity and signature, respectively. The connection of the translational and rotational symmetry of the model hamiltonian with the spurious solutions of the RPA equation of motion is discussed. Expressions for the reduced probabilities B(E1), B(E2) and B(E3) are obtained. These expressions confirm the conclusions of phenomenological models for the strong E1 and E3 intraband transitions in nuclei with stable octupole deformation.

  7. Exotic octupole deformation in proton-rich Z=N nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Takami, Satoshi; Yabana, K. [Niigata Univ. (Japan); Matsuo, M.

    1998-03-01

    We study static non-axial octupole deformations in proton-rich Z=N nuclei, {sup 64}Ge, {sup 68}Se, {sup 72}Kr, {sup 76}Sr, {sup 80}Zr and {sup 84}Mo, by using the Skyrme Hartree-Fock plus BCS method with no restrictions on the nuclear shape. The calculation predicts that the oblate ground state in {sup 68}Se is extremely soft for the Y{sub 33} triangular deformation, and that in {sup 80}Zr the low-lying local minimum state coexisting with the prolate ground state has the Y{sub 32} tetrahedral deformation. (author)

  8. Nonaxial octupole deformations in light N=Z nuclei at high spins

    OpenAIRE

    Tanaka, Takeshi; Nazmitdinov, Rashid G.; Iwasawa, Kazuo

    2000-01-01

    High spin states of ^{32}S$ and ^{56}Ni are investigated by means of the cranking Hartree-Fock method with the Gogny interaction without imposing a restriction on the axial reflection symmetry. It was found that a non-axial octupole deformation of the Y_{31} type becomes important in the yrast states of ^{32}S. A similar effect is predicted for the nucleus ^{56}Ni.

  9. Nonaxial octupole deformations in light N = Z nuclei at high spins

    CERN Document Server

    Tanaka, T; Iwasawa, K; Tanaka, Takeshi; Nazmitdinov, Rashid G.; Iwasawa, Kazuo

    2001-01-01

    High spin states of ^{32}S$ and ^{56}Ni are investigated by means of the cranking Hartree-Fock method with the Gogny interaction without imposing a restriction on the axial reflection symmetry. It was found that a non-axial octupole deformation of the Y_{31} type becomes important in the yrast states of ^{32}S. A similar effect is predicted for the nucleus ^{56}Ni.

  10. Role of the proton-neutron interaction in a ?100 nuclei and properties of the 96Zr double octupole multiplet

    International Nuclear Information System (INIS)

    In this paper experimental evidence is presented for the role of a strong proton-neutron interaction brought about by the 3S1 force acting through orbits with large overlap. This leads to support for the concept of the 1g9/2-protons interacting with the lg7/2-neutrons to give rise to deformation in this mass region. Evidence is considered that once deformation is established, the weaker lg9/2-proton, lh11/2-neutron interaction and the associated strongly downsloping lh11/2-neutron Nilsson state orbits stabilize deformation. The properties of the recently discovered double octupole vibration multiplet in 96Zr is presented and compared to spdf-boson IBM calculations. Evidence is found for strong mixing of some of the double octupole state members and concomitant fragmentation among the positive parity levels. This is taken to suggest that in most nuclei, the double octupole multiplet and its strength is spread over the positive parity spectra and hence, not observed as single entities

  11. Octupole shapes in heavy nuclei

    International Nuclear Information System (INIS)

    Theoretical calculations and measurements show the presence of strong octupole correlations in thecyround states and low-lying states of odd-mass and odd-odd nuclei in the RaPa region. Evidence for octupole correlations is provided by the observation of parity doublets and reductions in M1 matrix elements, decoupling parameters, and Coriolis matrix elements Involving high-j states. Enhancement of E1 transition rates has also been observed for some of the octupole deformed nuclei. The most convincing argument for octupole deformation is provided by the similarities of the reduced alpha decay rates to the two members of parity doublets

  12. Identification of excited states and evidence for octupole deformation in sup 2 sup 2 sup 6 U

    CERN Document Server

    Greenlees, P T

    1999-01-01

    Excited yrast states in the neutron-deficient nucleus sup 2 sup 2 sup 6 U have been identified in two experiments performed at the Accelerator Laboratory of the University of Jyvaeskylae, Finland. In the first, the technique of recoil-decay tagging was employed using the JUROSPHERE plus RITU device, where the reaction channel of interest is selected through correlation with a characteristic decay. In the second, the RITU device was employed to study the alpha decay of sup 2 sup 3 sup 0 Pu. Through these experiments the level scheme of sup 2 sup 2 sup 6 U was deduced for the first time. Interleaved bands of positive- and negative- parity states suggest the octupole nature of this nucleus, and the behaviour of the difference in aligned angular momentum between the negative- and positive- parity states with rotational frequency is consistent with that expected of a rotating reflection-asymmetric shape. This represents an extension of the known octupole-deformed nuclei to Z = 92. The interleaved bands of alternat...

  13. High-spin study of octupole-deformed 222Th and reduction of the background from prompt fission

    International Nuclear Information System (INIS)

    High-spin states have been studied in the octupole-deformed 222Th nucleus using the 208Pb(18O,4n) reaction. De-excitation gamma rays were detected using the Euroball-IV gamma-ray spectrometer. The large background of gamma rays from prompt fission fragments, which generally hampers the spectroscopy of actinide nuclei in fusion-evaporation reactions, has been reduced using the Euroball-IV inner BGO ball as a sum-energy filter. With the requirement that the summed gamma-ray energy detected in the reaction is less than 10 MeV, the intensity of 222Th gamma-rays, relative to the prompt fission background is significantly improved. The experiment and data analysis are discussed, and preliminary spectroscopic results are presented

  14. Investigation of octupole deformations in the Fr217 nucleus by yrast spectroscopy

    International Nuclear Information System (INIS)

    The spectroscopic characteristics of the yrast levels of Fr217 are determined. The level scheme up to a value of J = (39/2+) for angular momentum and parity is established. The production of the Fr217 nucleus in a heavy ion collision reaction was only possible by using a radioactive Pb210 target. The method for preparing the target is described. The Fr217 nucleus belongs to the category of nuclei showing octupole effects. Mass A = 217 seems to be the lower limit of the region where these effects occur

  15. 'Staggering' effect in even-even nuclei with quadrupole and octupole deformations

    International Nuclear Information System (INIS)

    Full text: The odd-even staggering effect is known as a zigzagging behaviour of the nuclear inertial parameter between the odd and even angular momentum states of a rotational band. It is characterized by a relative displacement of the odd angular momentum levels with respect to the even ones. The analysis and the interpretation of this effect are of current interest since it carries detailed information about the fine structure of the nuclear collective spectrum in different regions of the nuclear chart. The odd-even staggering patterns can be determined as Stag(I)=6?E(I) - 4?E(I-1) - 4?E(I+1)+?E(I+2)+?E(I-2) here ?E(I)=E(I+1) - E(I), E(I)-energy levels [1], I-spin of the excited states of even-even nuclei. Stag (I) is very sensitive to the fine structure of rotational spectra and provides spectacular ?I=1 staggering patterns (zigzagging behaviour of the function Stag (I) with clearly defined zero reference) in various rotational bands. On this basis we propose a relevant theoretical analysis of the ?I=1 staggering effects in nuclear octupole bands in reference to the underlying reflection-asymmetric shape characteristics of the nuclear collective motion. The behaviour of the odd-even (?I=1) staggering effect in the nuclei 152,154Sm, 154,156,158Gd, 156Dy, 162,164Er, 228Th, 236,238U has been considered and shown that the odd-even staggering patterns do not vanish in the observed regio not vanish in the observed region of angular momentum. (author) Reference: 1. Sh. Sharipov, M. S. Nadirbekov, G. A. Yuldasheva Ukrainian Journal of Physics, 53,11(2008)

  16. Influence of shell effects and stable octupole deformation on the E1 and E2 transition rates in the heavy-Ba region

    International Nuclear Information System (INIS)

    Lifetimes were measured for the 21+, 41+, 02+, 11-, and 31- levels in 142,144,146Ba using a recently developed ?-?-? fast timing method. In 146Ba, the Q0 moment for the negative parity band was slightly larger than that for the positive parity band. The isovector E1 rates which were very small in 146Ba and large in 144Ba can be explained in terms of shell effects on the electric dipole moment. The new data are interpreted by both the spdf interacting boson and the reflection-asymmetric deformed shell models and provide compelling evidence for a static octupole deformation near 146Ba

  17. Properties of octupole-vibrational bands in the 160Dy nucleus

    Science.gov (United States)

    Usmanov, P. N.; Solnyshkin, A. A.; Vdovin, A. I.; Salikhbaev, U. S.

    2014-11-01

    The mixing of octupole-vibrational bands in the 160Dy nucleus is analyzed within a phenomenological model that involves Coriolis coupling. The energies of levels in the bands, the reduced probabilities for E1 transitions from the octupole-vibrational bands to the ground-state and ? bands, and the ratios of the reduced probabilities for these transitions to the neighboring levels of the ground-state band are calculated. Satisfactory agreement with available experimental data is reached.

  18. The microscopic description of the collective states of rotating octupole deformed atomic nuclei. Formulation of the model

    International Nuclear Information System (INIS)

    The microscopic model for the description of collective states of rotating nuclei with intrinsic reflection asymmetry is formulated. The Hamiltonian of the model contains as a residual interaction separable octupole-octupole and quadrupole-quadrupole forces. The model is analysed by the method combining the cranking model and random phase approximation. Existence of the Ssub(x)=PRsub(x)sup(-1)(?) combined symmetry allows one to classify solutions by quantum number - the generalized signature. Some consequencies caused by the requirements of translational and rotational symmetries of the model Hamiltonian are investigated

  19. Octupole correlations in the heavy elements

    International Nuclear Information System (INIS)

    The effects of octupole correlations on the nuclear structure of the heavy elements are discussed. The cluster model description of the heavy elements is analyzed. The relevance of 26-pole deformation and fast El transitions to an octupole model is considered. 30 refs., 21 figs., 1 tab

  20. Coupling of nuclear quadrupole and octupole degrees of freedom in an angular momentum dependent potential of two deformation variables

    International Nuclear Information System (INIS)

    We propose a collective rotation-vibration Hamiltonian of nuclei in which the axial quadrupole ?2 and octupole ?3 variables are coupled through the centrifugal interaction. We consider that the system oscillates between positive and negative ?3-values by rounding a potential core in the (?2,?3)- space. We examine the effect of the 'rounding' in the structure of the spectrum

  1. Test of the transport properties of a helical electrostatic quadrupole and quasi-octupole

    International Nuclear Information System (INIS)

    A third-generation continuous helical electrostatic quadrupole (HESQ) lens has been built and tested. The new HESQ is 21.5 cm long and has a 3.6 cm diameter aperture. The HESQ has been tested under two separate conditions: with a pulsed 25 keV, 0.5 mA proton beam; and a 25 keV, 10 mA proton beam. The input emittance was fixed using a multi-aperture collimator. A comparison is made between experiment and numerical simulations for a wide variety of operating conditions. A second possible operating mode is the quasi-octupole mode, which offers significantly reduced aberration when compared to the quadrupole mode. The results of preliminary tests in this operating mode will be presented

  2. Test of the transport properties of a helical electrostatic quadrupole and quasi-octupole

    International Nuclear Information System (INIS)

    A third-generation continuous helical electrostatic quadrupole (HESQ) lens has been built and tested. The new HESQ is 21.5 cm long and has a 3.6 cm diameter aperture. The HESQ has been tested under two separate conditions: With a pulsed 25 keV, 0.5 mA proton beam; and a 25 keV, 10 mA proton beam. The input emittance was fixed using a multi-aperture collimator. A comparison is made between experiment and numerical simulations for a wide variety of operating conditions. A second possible operating mode is the quasi-octupole mode which offers significantly reduced aberration when compared to the quadrupole mode. The results of preliminary tests in this operating mode will be presented

  3. Octupole vibrations at high angular momenta

    CERN Document Server

    Nakatsukasa, T

    1995-01-01

    Properties of octupole vibrations in rapidly rotating nuclei are discussed. Microscopic RPA calculations based on the cranked shell model are performed to investigate the interplay between rotation and vibrations. The ability of this model to describe the properties of collective vibrations built on the ground bands in rare-earth and actinide nuclei is demonstrated at high angular momentum. The octupole vibrational states in even-even superdeformed Hg nuclei are also predicted and compared with available experimental data. A new interpretation of the observed excited superdeformed bands invoking these octupole bands is proposed.

  4. Octupole deformation in /sup 227/Ac by single-proton stripping reactions: /sup 226/Ra(?, t)/sup 227/Ac and /sup 226/Ra(3He,d)/sup 227/Ac

    International Nuclear Information System (INIS)

    A radioactive /sup 226/Ra (t/sub 1/2/ = 1600 yr) target was used to study the /sup 226/Ra(?,t)/sup 227/Ac and /sup 226/Ra(3He,d)/sup 227/Ac reactions at an incident energy of 30 MeV for both the ? and 3He particles. These measurements have confirmed most levels observed in earlier decay-scheme studies, and give evidence for 11 additional levels. Several of the new levels were used in the tentative assignment of two K/sup ?/ = (5/2/sup +- / bands. The experimental data are compared with results from the Nilsson model and a nonadiabatic, rigid, reflection-asymmetric rotor (octupole) model. Although the order and spacing of levels in this mass region can be explained better by models that include an octupole deformation, the spectroscopic strengths in /sup 227/Ac are in better agreement with those calculated for the reflection-symmetric potential

  5. Simultaneous quadrupole and octupole shape phase transitions in Thorium

    International Nuclear Information System (INIS)

    The evolution of quadrupole and octupole shapes in Th isotopes is studied in the framework of nuclear Density Functional Theory. Constrained energy maps and observables calculated with microscopic collective Hamiltonians indicate the occurrence of a simultaneous quantum shape phase transition between spherical and quadrupole-deformed prolate shapes, and between non-octupole and octupole-deformed shapes, as functions of the neutron number. The nucleus 224Th is closest to the critical point of a double phase transition. A microscopic mechanism of this phenomenon is discussed in terms of the evolution of single-nucleon orbitals with deformation

  6. Petrophysical Properties of Deformed Sandstone Reservoir

    OpenAIRE

    Shekari-namin, Saeideh

    2012-01-01

    Small scale deformation structures that mostly occur in highly porous rocks are called deformation bands. Petrophysical characteristics of deformation bands are different from those of host rock and they can act as barriers or conduit to fluid flow. The effect on fluid flow is the most important property of these structures which is essential in many geological fields; for instance oil & gas, CO2 storage and ground water flow, when permeability and capillary pressure are the tw...

  7. About octupole states in the 158Dy and the 168Er nuclei

    International Nuclear Information System (INIS)

    The properties of negative parity low-lying states in 158Dy and 168Er in the random phase approximation based on the cranking model are investigated. Octupole-octupole forces have been used as a residual interaction. Calculated energy levels are compared with the experimental ones, and also with the energy values obtained with making allowance for dipole-dipole, octupole-octupole and dipole-octupole type forces. The resuits of calculation by the used model permit to understand the nature of negative parity low-lying states

  8. Energy levels and reduced probabilities of electric dipole, quadrupole and octupole transitions of 226Ra

    International Nuclear Information System (INIS)

    The energy levels and reduced probabilities of electric dipole, quadrupole and octupole transitions measured in the Coulomb excitation of 226Ra are analyzed in the framework of the soft axial-symmetric rotator model with quadrupole and octupole deformations. The calculated values are in good agreement with experimental data. (author). 11 refs., 2 figs

  9. Search for octupole correlations in $^{147}$Nd

    CERN Document Server

    Ruchowska, E; Kowal, M; Skalski, J; Plociennik, W A; Fogelberg, B

    2015-01-01

    Properties of excited states in $^{147}$Nd have been studied with multispectra and $\\gamma \\gamma$ coincidence measurements. Twenty-four new $\\gamma$-lines and three new levels have been introduced into the level scheme of $^{147}$Nd. Lifetimes of eight excited levels in $^{147}$Nd, populated in the $\\beta$ decay of $^{147}$Pr, have been measured using the advanced time-delayed $\\beta\\gamma\\gamma$(t) method. Reduced transition probabilities have been determined for 30 $\\gamma$-transitions in $^{147}$Nd. Potential energy surfaces on the ($\\beta_{2}$,$\\beta_{3}$) plane calculated for $^{147}$Nd using the Strutinsky method predict two single quasiparticle configurations with nonzero octupole deformation, with K=1/2 and K=5/2. We do not observe parity doublet bands with K=5/2. For pair of opposite parity bands that could form the K=1/2 parity doublet we were able only to determine lower limit of the dipole moment, $|D_0|\\geq$0.02 e$\\cdot fm$.

  10. Octupole Effects of Nuclei Near 11256Ba56

    Science.gov (United States)

    Wang, Hua-Lei; Jiang, Jin-Ge; Liu, Hong-Liang; Xu, Fu-Rong

    2013-11-01

    Octupole instabilities in even-even nuclei near 11256Ba56 nucleus have been investigated by means of improved total-Routhian-surface calculations with the inclusion of reflection-asymmetric deformations. It is found that the shape evolutions of mirror nuclei are similar between Z = 56 isotopes and N = 56 isotones in the ground-states. As an example, 10852Te56, which has reflection-symmetric shape at low spins, is predicted to be octupole deformed at certain high rotational frequencies. The prediction is confirmed by experiment.

  11. Quadrupole and octupole collectivity in 148Nd

    International Nuclear Information System (INIS)

    The role of quadrupole and octupole collectivity in the shape-transitional nucleus 148Nd has been studied by Coulomb excitation using beams of 58Ni and 92Mo, and a beam of 148Nd (using a 208Pb target). The extracted E1, E2 and E3 matrix elements involving states up to 12+ in the ground band and 13- in the negative-parity band are presented, and compared to calculations that assume a vibrational and rotational octupole nature for the negative-parity band. The positive-parity ground-band states are well described in terms of a prolate deformed shape with Q20?400 e fm2 (?2rms?+0.18). The present results suggest a vibrational octupole nature for the low-spin negative-parity states, with an intrinsic moment Q30?1500 e fm3 (?3rms?0.12). The E2 and E3 matrix elements connecting these bands to the ?- and ?-vibrational bands (and within these bands) are also presented, and compared to calculations incorporating the coupling between the rotational and vibrational modes. These calculations describe reasonably well the E2 matrix elements involving the gamma band, but do not reproduce the measured E2 matrix elements for the beta band, implying a complicated intrinsic structure for the beta band. The strong enhancement of the measured E3 matrix elements connecting the negative-parity band to the beta band coarity band to the beta band could be indicative of a significant component of the two-phonon octupole vibration in the wavefunction of the so-called beta band. (orig.)

  12. Magnetic properties of deformed superconductors

    International Nuclear Information System (INIS)

    This communication concerns the geometric effect on magnetic properties of superconductors. The metric description for quantum particles holds only in limited class of medium and the screw-dislocated medium is considered. When the Ginzburg-Landau equation with Maxwell's equations was solved based on this description, it was shown that self-adjointness of the operator is guaranteed by specified solutions. As a result, isolated vortex exists at dislocation line. -- Highlights: ? The screw-dislocated superconductors with tight-binding approximation. ? The quantum singularity is removed by specific solution. ? Isolated vortex exists at dislocation line.

  13. Collective Properties of Low-lying Octupole Excitations in $^{208}_{82}Pb_{126}$, $^{60}_{20}Ca_{40}$ and $^{28}_{8}O_{20}$

    CERN Document Server

    Zhou, X R; Dong, B G; Zhang, X Z; Long, G L

    2003-01-01

    The octupole strengths of $\\beta$-stable nucleus $^{208}_{82}Pb_{126}$, a neutron skin nucleus $^{60}_{20}Ca_{40}$ and a neutron drip line nucleus $^{28}_{8}O_{20}$ are studied by using the self-consistent Hartree-Fock calculation plus the random phase approximation (RPA) with Skyrme interaction. The collective properties of low-lying excitations are analyzed by using particle-vibration coupling. The results show that the lowest isoscalar states above threshold in $^{60}_{20}Ca_{40}$ and $^{28}_{8}O_{20}$ are the superpositions of collective excitations and unperturbed transitions from bound state to nonresonance states. For these three nuclei, both the low-lying isoscalar states and giant isoscalar resonance carry isovector strength. The ratio B(IV)/B(IS) is checked. It is found that, for $^{208}_{82}Pb_{126}$, the ratios are equal to $(\\frac{N-Z}{A})^2$ in good accuracy, while for $^{60}_{20}Ca_{40}$ and $^{28}_{8}O_{20}$, the ratios are much larger than $(\\frac{N-Z}{A})^2$. This results from the excess neu...

  14. Non-yrast quadrupole-octupole spectra

    Directory of Open Access Journals (Sweden)

    Lenske H.

    2012-12-01

    Full Text Available A model of strongly coupled quadrupole and octupole vibrations and rotations is applied to describe non-yrast alternating-parity sequences in even-even nuclei and split parity-doublet spectra in odd-mass nuclei. In even-even nuclei the yrast alternating-parity sequence includes the ground-state band and the lowest negative-parity levels with odd angular momenta, while the non-yrast sequences include excited ?-bands and higher negative-parity levels. In odd-mass nuclei the yrast levels are described as low-energy rotation-vibration modes coupled to the ground single-particle (s.p. state, while the non-yrast parity-doublets are obtained as higher-energy rotation-vibration modes coupled to excited s.p. configurations. We show that the extended model scheme describes the yrast and non-yrast quadrupole-octupole spectra in both even-even and odd-A nuclei. The involvement of the reflection-asymmetric deformed shell model to explain the single-particle motion and the Coriolis interaction in odd nuclei is discussed.

  15. Stable and Vibrational Octupole Modes in Mo, Xe, Ba, La, Ce and Nd

    International Nuclear Information System (INIS)

    Evidence is presented for stable octupole deformation in neutron-rich nuclei, bounded by Z = 54-58 and N = 85-92. To either side of this region negative parity bands built on more vibrational type octupole modes are observed in 140Ba and 152,154Nd. The largest stable octupole deformation (?s ? 0.1) is found in 144Baas. The theoretically predicted quenching (?s ? 0) of stable octupole deformation at higher spins is found in 140Ba. There is good agreement between theory and experiment for the strongly varying electric dipole moments as a function of mass for 142-141Ba. In odd-A 142Ba and odd-Z 140La, we observe parity doublets, two pairs of positive and negative parity bands with opposite spins. In 145La a strong coupled ground band with symmetric shape coexists with the asymmetric octupole shape which stabilizes above about spin 19/2. In 145,147La a strong reduction in E2 strength around 25/2 from band crossing is observed. The isotope 109Mo was identified and a new region of stable uctpole deformation is identified in 107,108Mo centered around N = 64-66 as earlier predicted. This is the first case of stable uctpole deformation involving only one pair of orbitals

  16. On octupole alignment in actinides

    Energy Technology Data Exchange (ETDEWEB)

    Nazmitdinov, R.G.; Mikhailov, I.N.; Briancon, C.

    1987-04-09

    The alignment of the octupole angular momentum in the rotational states of the K/sup ..pi../ = 0/sup -/ band is analysed in the microscopic model. The model describes qualitatively the branching ratio for the E1-transitions from these states to the ground band states.

  17. On octupole alignment in actinides

    International Nuclear Information System (INIS)

    The alignment of the octupole angular momentum in the rotational states of the K? = 0- band is analysed in the microscopic model. The model describes qualitatively the branching ratio for the E1-transitions from these states to the ground band states. (orig.)

  18. Octupole correlations in superdeformed nuclei

    International Nuclear Information System (INIS)

    Octupole correlations have been investigated within the Generator Coordinate Method based upon Hartree-Fock plus BCS wavefunctions. GCM states corresponding to the q30 and q32 modes have been built up to describe the SD excited bands which have been recently observed as negative parity bands. (authors)

  19. The octupoles take pole position

    CERN Multimedia

    2002-01-01

    The first preseries octupole magnet was delivered to CERN in December 2001. Hooked up to a main quadrupole magnet, its function will be to correct imperfections in the beams. The LHC will be fitted with about 5000 corrector magnets, whose task it will be to provide maximum precision in beam collisions.

  20. AGS correction quadrupoles and octupoles

    International Nuclear Information System (INIS)

    A pole-face design is presented for a set of correction quadrupoles and a set of correction octupoles required in the Brookhaven AGS. The pole-face design consists of a circular pole which is terminated by radial lines tangent to the circle. The radius of the circle is chosen to cause the lowest undesired multipole present to vanish. (U.S.)

  1. Studies of electric dipole moments in the octupole collective regions of heavy Radiums and Bariums

    CERN Multimedia

    Hoff, P; Kaczarowski, R

    2002-01-01

    %IS386 %title\\ \\It is proposed to study the electric dipole moments in the regions of octupole collective Ra-Th and Ba-Ce nuclei by means of Advanced Time-Delayed (ATD) $\\beta\\gamma\\gamma(t)$ method with a primary goal to provide new and critical data on the properties of E1 moments. The proposal focuses on the nuclei of $^{225,226,229}$Ra, $^{229,233}$Th and $^{149,150}$Ba.\\ \\The ATD $\\beta\\gamma\\gamma$(t) method was first tested at ISOLDE as part of the IS322 study of Fr-Ra nuclei at the limits of octupole deformation region. The results have greatly increased the knowledge of electric dipole moments in the region and demonstrated that new and unique research capabilities in this field are now available at ISOLDE. Based on the experience and new systematics, we propose a specialized study with the aim to determine the missing key aspects of the E1 moment systematics. We propose : \\begin{enumerate}[a)] \\item to measure the lifetimes of the 1$_{1}^{-}$ and 3$_{1}^{-}$ states in $^{226}$Ra with $\\sim$15\\% prec...

  2. Mechanical Properties and Deformation Behavior of Bulk Metallic Glasses

    Directory of Open Access Journals (Sweden)

    Alexander Yu. Churyumov

    2012-12-01

    Full Text Available Metallic glasses demonstrate unique properties, including large elastic limit and high strength, which make them attractive for practical applications. Unlike crystalline alloys, metallic glasses, in general, do not exhibit a strain hardening effect, while plastic deformation at room temperature is localized in narrow shear bands. Room-temperature mechanical properties and deformation behavior of bulk metallic glassy samples and the crystal-glassy composites are reviewed in the present paper.

  3. Octupole magnet for expansion of irradiation area

    Energy Technology Data Exchange (ETDEWEB)

    Morita, Akio; Inoue, Makoto; Noda, Akira; Iwashita, Yoshihisa; Shirai, Toshiyuki; Urakabe, Eriko [Kyoto Univ., Uji (Japan). Inst. for Chemical Research; Hiramoto, Kazuo; Noda, Kouji

    1997-12-31

    An octupole magnet for experiments is designed to prove a scheme for expanding beam irradiation area with good flatness. The length and maximum strength of the octupole field 1/3{exclamation_point} B``` are 0.6 m and 4000 T/m{sup 3}, respectively. (author)

  4. Microstructure, properties and hot deformability of the new maraging steels

    OpenAIRE

    Pawlak, S. J.; Zalecki, W.

    2008-01-01

    Purpose: The effects of relevant metallurgical factors on the structure, fracture mode and properties of the high cobalt and cobalt free maraging steel has been studied. The aim was to better understand structure-property relations and enhance mechanical properties of the steels. To provide data needed for production and manufacturing technology, the high temperature deformability using physical simulation method was used.Design/methodology/approach: To study structure-property relation, broa...

  5. Some properties of deformed q-numbers

    Scientific Electronic Library Online (English)

    Thierry C. Petit, Lobão; Pedro G. S., Cardoso; Suani T. R., Pinho; Ernesto P., Borges.

    2009-08-01

    Full Text Available Nonextensive statistical mechanics has been a source of investigation in mathematical structures such as deformed algebraic structures. In this work, we present some consequences of q-operations on the construction of q-numbers for all numerical sets. Based on such a construction, we present a new p [...] roduct that distributes over the q-sum. Finally, we present different patterns of q-Pascal's triangles, based on q-sum, whose elements are q-numbers.

  6. Quadrupole-octupole coupled states in 112Cd

    International Nuclear Information System (INIS)

    The properties of negative-parity states in the 2.5 MeV region in 112Cd have been investigated with the (n,n'?) reaction. For many of these levels, lifetimes have been measured, and B(E1) and B(E2) values for their decays have been determined. Several transitions exhibit enhanced B(E2) values for decay to the 31- octupole state, indicative of quadrupole-octupole coupled (2+circle-times 3-) states. The B(E1) values observed are typically in the range of 1 - 5x10-4 Weisskopf units (W.u.), irrespective of the final state. copyright 1999 The American Physical Society

  7. Microscopic description of octupole shape-phase transitions in light actinide and rare-earth nuclei

    Science.gov (United States)

    Nomura, K.; Vretenar, D.; Nikši?, T.; Lu, Bing-Nan

    2014-02-01

    A systematic analysis of low-lying quadrupole and octupole collective states is presented based on the microscopic energy density functional framework. By mapping the deformation constrained self-consistent axially symmetric mean-field energy surfaces onto the equivalent Hamiltonian of the sdf interacting boson model (IBM), that is, onto the energy expectation value in the boson condensate state, the Hamiltonian parameters are determined. The study is based on the global relativistic energy density functional DD-PC1. The resulting IBM Hamiltonian is used to calculate excitation spectra and transition rates for the positive- and negative-parity collective states in four isotopic chains characteristic for two regions of octupole deformation and collectivity: Th, Ra, Sm, and Ba. Consistent with the empirical trend, the microscopic calculation based on the systematics of ?2-?3 energy maps, the resulting low-lying negative-parity bands and transition rates show evidence of a shape transition between stable octupole deformation and octupole vibrations characteristic for ?3-soft potentials.

  8. q -deformed noncommutative cat states and their nonclassical properties

    Science.gov (United States)

    Dey, Sanjib

    2015-02-01

    We study several classical-like properties of q -deformed nonlinear coherent states as well as nonclassical behaviors of q -deformed version of the Schrödinger cat states in noncommutative space. Coherent states in q -deformed space are found to be minimum uncertainty states together with the squeezed photon distributions unlike the ordinary systems, where the photon distributions are always Poissonian. Several advantages of utilizing cat states in noncommutative space over the standard quantum mechanical spaces have been reported here. For instance, the q -deformed parameter has been utilized to improve the squeezing of the quadrature beyond the ordinary case. Most importantly, the parameter provides an extra degree of freedom by which we achieve both quadrature squeezed and number squeezed cat states at the same time in a single system, which is impossible to achieve from ordinary cat states.

  9. Nuclear magnetic dipole properties and the triaxial deformation

    CERN Document Server

    Sun, Y; Long, G L; Sun, Yang; Sheikh, Javid A.; Long, Gui-Lu

    2002-01-01

    Nuclear magnetic dipole properties of ground bands and gamma-vibrational bands are studied for the first time using the triaxial projected shell model approach. The study is carried out for the Dy and Er isotopic chains, ranging from transitional to well-deformed region. It is found that the g-factor ratio of the 2^+ state in ground bands to that of gamma-bands, r=g(2^+, gamma-vib)/g(2^+, ground), varies along an isotopic chain. With the gamma-deformations, which best reproduce the energy levels for both bands, we obtain a qualitative agreement with the experimental data. This result thus suggests that study of the ratio may provide an important information on the triaxial deformation of a nuclear system. The angular-momentum dependence of the ground band g-factor on the triaxial deformation is also investigated.

  10. Deformation properties of the BCP energy density functional

    CERN Document Server

    Robledo, L M; Schuck, P; Viñas, X

    2008-01-01

    We explore the deformation properties of the newly postulated BCP energy density functional (EDF). The results obtained for three isotope chains of Mg, Dy and Ra are compared to the available experimental data as well as to the results of the Gogny-D1S force. Results for the fission barrier of $^{240}$Pu are also discussed.

  11. Mechanical deformation mechanisms and properties of amyloid fibrils.

    Science.gov (United States)

    Choi, Bumjoon; Yoon, Gwonchan; Lee, Sang Woo; Eom, Kilho

    2015-01-14

    Amyloid fibrils have recently received attention due to their remarkable mechanical properties, which are highly correlated with their biological functions. We have studied the mechanical deformation mechanisms and properties of amyloid fibrils as a function of their length scales by using atomistic simulations. It is shown that the length of amyloid fibrils plays a role in their deformation and fracture mechanisms in such a way that the competition between shear and bending deformations is highly dependent on the fibril length, and that as the fibril length increases, so does the bending strength of the fibril while its shear strength decreases. The dependence of rupture force for amyloid fibrils on their length is elucidated using the Bell model, which suggests that the rupture force of the fibril is determined from the hydrogen bond rupture mechanism that critically depends on the fibril length. We have measured the toughness of amyloid fibrils, which is shown to depend on the fibril length. In particular, the toughness of the fibril with its length of ?3 nm is estimated to be ?30 kcal mol(-1) nm(-3), comparable to that of a spider silk crystal with its length of ?2 nm. Moreover, we have shown the important effect of the pulling rate on the mechanical deformation mechanisms and properties of amyloid fibril. It is found that as the pulling rate increases, so does the contribution of the shear effect to the elastic deformation of the amyloid fibril with its length of 15 nm is almost independent of the pulling rate. Our study sheds light on the role of the length scale of amyloid fibrils and the pulling rate in their mechanical behaviors and properties, which may provide insights into how the excellent mechanical properties of protein fibrils can be determined. PMID:25426573

  12. Nd-Fe-B-Cu hot deformation processing: a comparison of deformation modes, microstructural development and magnetic properties

    International Nuclear Information System (INIS)

    Due to its relative simplicity and low cost the hot deformation of Nd-Fe-B ingots is rapidly reaching the status of a valid alternative to sintering. Among the possible deformation modes, pressing, rolling and forging are perhaps the most successful. This paper describes the research programme undertaken so far, by discussing the relationship between deformation mode, microstructure and magnetic properties of magnets produced by hot deformation mode, microstructure and magnetic properties of magnets produced by hot deformation of a number of Nd-fe-B-Cu alloys. Microstructural observation showed that both pressed and forged samples are characterized by a heterogeneous microstructure and from magnetic measurements it was concluded that magnetic properties differ when taken in the center or in the periphery of the sample. On the other hand roller magnets were homogeneous both in terms of microstructure and magnetic properties, and interpretations of the mechanisms of texture development and of microstructural development of hot deformed magnets is put forward. (author)

  13. Tuning functional properties by plastic deformation

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, A R; Neu, V; Haenisch, J; Huehne, R; Freudenberger, J; Holzapfel, B; Schultz, L; Faehler, S [IFW Dresden, Institute for Metallic Materials, PO Box 270116, 01171 Dresden (Germany); Matias, V [Superconductivity Technology Center, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)], E-mail: s.faehler@ifw-dresden.de

    2009-08-15

    It is well known that a variation of lattice constants can strongly influence the functional properties of materials. Lattice constants can be influenced by external forces; however, most experiments are limited to hydrostatic pressure or biaxial stress. Here, we present an experimental approach that imposes a large uniaxial strain on epitaxially grown films in order to tune their functional properties. A substrate made of a ductile metal alloy covered with a biaxially oriented MgO layer is used as a template for growth of epitaxial films. By applying an external plastic strain, we break the symmetry within the substrate plane compared to the as-deposited state. The consequences of 2% plastic strain are examined for an epitaxial hard magnetic Nd{sub 2}Fe{sub 14}B film and are found to result in an elliptical distortion of the in-plane anisotropy below the spin-reorientation temperature. Our approach is a versatile method to study the influence of large plastic strain on various materials, as the MgO(001) layer used is a common substrate for epitaxial growth.

  14. The electrochemical properties of the cyclic deformed passive metals

    International Nuclear Information System (INIS)

    It has been investigated the influence of chloride environment on corrosion fatigue fracture of different classes stainless steels. The change of electrochemical properties of deformed corrosion resistance steels and alloys during the initial stage of corrosion fatigue fracture has been studied. It has been determined the influence of micro-deformation processes of surface at different tensions on the electrochemical activating of stainless steels. The critical values of electrochemical parameters of the deformed metal has been established, at which probability of corrosion fatigue fracture grows sharply. The features of character change polarization current of stainless steels at loadings even to corrosion fatigue limit has been shown. It served by basis for development of method speed-up determination of corrosion fatigue limit without destruction of specimens. It has been established possibility of decline corrosion currents of stainless steels as a result of deformation at tensions which do not cause destruction. It was revealed the reason of this effect: different acceleration by mechanical tensions of dissolution of alloys separate components, that results in enrichment of surface by a chrome and nickel. It is instrumental in the improvement of protective properties of passive tapes. The analysis of results of the conducted researches allowed to set that corrosion endurance of stainless steels is determined by intensity of their electrochemical activating at tensions of even to corrosive fatigue limit. (authors)

  15. The electrochemical properties of the cyclic deformed passive metals

    Energy Technology Data Exchange (ETDEWEB)

    Pokhmurskii, V.; Khoma, M. [Karpenko Physico-Mechanical Institute of the National Academy of Sciences of Ukraine, 5 Naukova Str., Lviv, 79601 (Ukraine)

    2004-07-01

    It has been investigated the influence of chloride environment on corrosion fatigue fracture of different classes stainless steels. The change of electrochemical properties of deformed corrosion resistance steels and alloys during the initial stage of corrosion fatigue fracture has been studied. It has been determined the influence of micro-deformation processes of surface at different tensions on the electrochemical activating of stainless steels. The critical values of electrochemical parameters of the deformed metal has been established, at which probability of corrosion fatigue fracture grows sharply. The features of character change polarization current of stainless steels at loadings even to corrosion fatigue limit has been shown. It served by basis for development of method speed-up determination of corrosion fatigue limit without destruction of specimens. It has been established possibility of decline corrosion currents of stainless steels as a result of deformation at tensions which do not cause destruction. It was revealed the reason of this effect: different acceleration by mechanical tensions of dissolution of alloys separate components, that results in enrichment of surface by a chrome and nickel. It is instrumental in the improvement of protective properties of passive tapes. The analysis of results of the conducted researches allowed to set that corrosion endurance of stainless steels is determined by intensity of their electrochemical activating at tensions of even to corrosive fatigue limit. (authors)

  16. Microstructure, properties and hot deformability of the new maraging steels

    Directory of Open Access Journals (Sweden)

    S.J. Pawlak

    2008-07-01

    Full Text Available Purpose: The effects of relevant metallurgical factors on the structure, fracture mode and properties of the high cobalt and cobalt free maraging steel has been studied. The aim was to better understand structure-property relations and enhance mechanical properties of the steels. To provide data needed for production and manufacturing technology, the high temperature deformability using physical simulation method was used.Design/methodology/approach: To study structure-property relation, broad range of the experimental techniques was used: quantitative metallography, X-ray diffraction phase analysis, transmission electron microscopy and SEM fractography. The flow properties in the range of hot working processes were determined by physical simulation approach, using Gleeble 3800 system.Findings: The cobalt-free maraging steel proved to be a valuable structural steel. At much higher fracture toughness it had only about 100 MPa lower yield stress, compared to that of high cobalt steel. Fracture surface morphologies were highly dependent on the steel grade and type of the mechanical test. The hot stress-strain characteristics were established for cobalt free maraging steel and compared to that of a stainless steel.Research limitations/implications: To fully evaluate potential field of applications, deeper comparative studies of the high cobalt and cobalt-free maraging steels are needed, particularly fracture modes and service properties of some parts.Practical implications: Very high mechanical properties and fracture toughness values obtained for the steels studied, make them suitable for advanced structural applications. The studies on the hot deformation behaviour of the steels are of practical value for the hot working process development.Originality/value: Detailed evaluation of the metallurgical purity, microstructure and fracture modes, allowed for better understanding of the microstructure-property relationships in selected high strength steels. The results obtained are of practical value for the development, production and manufacture of the high strength maraging steels with improved properties.

  17. Microscopic description of octupole shape-phase transitions in light actinides and rare-earth nuclei

    CERN Document Server

    Nomura, K; Niksic, T; Lu, Bing-Nan

    2014-01-01

    A systematic analysis of low-lying quadrupole and octupole collective states is presented, based on the microscopic energy density functional framework. By mapping the deformation constrained self-consistent axially symmetric mean-field energy surfaces onto the equivalent Hamiltonian of the $sdf$ interacting boson model (IBM), that is, onto the energy expectation value in the boson condensate state, the Hamiltonian parameters are determined. The study is based on the global relativistic energy density functional DD-PC1. The resulting IBM Hamiltonian is used to calculate excitation spectra and transition rates for the positive- and negative-parity collective states in four isotopic chains characteristic for two regions of octupole deformation and collectivity: Th, Ra, Sm and Ba. Consistent with the empirical trend, the microscopic calculation based on the systematics of $\\beta_{2}$-$\\beta_{3}$ energy maps, the resulting low-lying negative-parity bands and transition rates show evidence of a shape transition be...

  18. Quadrupole-octupole coupled states in 114Cd

    International Nuclear Information System (INIS)

    The properties of negative-parity states in 114Cd have been studied with the (n,n'?) reaction. ?-ray angular distributions and excitation functions have been used to characterize the decays of these excited levels, and level lifetimes have been obtained with the Doppler-shift attenuation method. A set of five closely spaced, negative-parity states has been identified as the complete quadrupole-octupole quintuplet. These excited states and the observed transitions from these levels are compared to calculations performed in the framework of the spdf interacting boson model

  19. Strength and Deformation Properties of Tertiary Clay at Moesgaard Museum

    DEFF Research Database (Denmark)

    Kaufmann, Kristine Lee; Nielsen, Benjaminn Nordahl

    2010-01-01

    The tertiary clay at Moesgaard Museum near Aarhus in the eastern part of Jutland in Denmark is a highly plastic, glacially disturbed nappe of Viborg Clay. The clay is characterised as a swelling soil, which could lead to damaging of the building due to additional heave of the soil. To take this characteristic, as well as the strength and deformation properties, into account during the design phase, two consolidation tests and one triaxial test have been conducted. This paper evaluates the results of the laboratory tests leading to the preconsolidation stress, the deformation parameters consisting of the swelling pressure, the constrained modulus and the compression index, and the strength parameters comprising the undrained shear strength, the drained shear strength and the effective angle of internal friction

  20. Effect of plastic deformation on the magnetic properties of non-oriented electrical steels

    International Nuclear Information System (INIS)

    Total loss increase in electrical steels due to plastic deformation is mainly concentrated in hysteresis loss, while classical and anomalous components show a slight decrease. Deformation increases both low-induction and high-induction components. While the mechanical properties show a smooth evolution with the deformation, the magnetic properties show a large difference even at only 0.5% elongation

  1. Octupole signatures in 124,125Ba

    International Nuclear Information System (INIS)

    The ? decay of the nuclei 124,125Ba has been investigated with the EUROBALL array, using the reaction 64Ni+64Ni at Ebeam = 255 and 261 MeV. Six new E1 transitions have been found in the nucleus 125Ba, suggesting a significant role of octupole correlations in the origin of its parity doublets. The J? = 3- level of the nucleus 124Ba has been identified for the first time. Its excitation energy is in very good agreement with a prediction based on a microscopic model including octupole interactions

  2. Search for two-octupole-phonon states in 208Pb

    Science.gov (United States)

    Mariscotti, M. A. J.; Bes, D. R.; Reich, S. L.; Sofía, H. M.; Hungerford, P.; Kerr, S. A.; Schreckenbach, K.; Warner, D. D.; Davidson, W. F.; Gelletly, W.

    1983-10-01

    A search for two-phonon octupole vibrational states in 208Pb was carried out using the 207Pb(n th, ?) reaction at the High Flux Reactor of the Institut Laue-Langevin. The conversion electron spectrum was scanned with the spectrometer BILL with a sensitivity of 20 ?b in the 4-6 MeV interval. Coincidence and singles ?-ray measurements were performed at the end of the thermal neutron beam guide H22-F reaching a sensitivity of 80 ?b for energies above 0.511 MeV. In addition the singles spectrum was investigated with the pair spectrometer at the tangential beam facility. Levels have been observed at (energies in keV and parenthesis for tentative level identification and spin-parity assignments): 2614.4, 3 -; 3997, (3 -); 4084.7, 2 +; 4253, (2 -, 3 -); 4704, (2 -, 3 -); (4882.0), (0 +); (4904.9), (0 +); 4935, 2 +; (6343), (2 +) and the 0 -, 1 - capture state at 7367.9 keV. The 4882.0 keV level probably corresponds to the known two-neutron pairing vibration. Possible candidates for two-phonon octupole excitations are the (0 +)(4904.9) and 2 + 4935 keV states. The nuclear field theory formalism is used to calculate branching ratios and energies for states in 208Pb under several assumptions. The most inimportant result of the comparison of theory and experiment is that the experimental properties of the 2 + 4935 keV state favour the interpretation of this state as a two-phonon octupole vibration rather than as a one-phonon non-collective quadrupole state.

  3. Effects of coupled structural and diagenetic processes on deformation localization and flow properties of deformation bands in sandstone

    Science.gov (United States)

    Elliott, Sara; Eichhubl, Peter; Landry, Chris

    2014-05-01

    Deformation bands tend to restrict flow perpendicular to the bands through the combined effects of porosity reduction, mechanical grain size reduction, and preferred cementation relative to the adjacent host rock. Thus, deformation bands may impart a permeability anisotropy to reservoir rocks. Deformation bands that occur in association with reservoir scale faults can impact reservoir-scale fluid flow and fault seal behavior. Using a combination of textural imaging including SEM-based cathodoluminescence imaging, compositional analysis, and lab petrophysics, this study is designed to (1) assess the effects of coupled chemical and mechanical processes leading to deformation localization in deformation bands and (2) to quantify the effect of these processes on single and multiphase fluid flow. While the effects of mechanical processes including grain translation, rotation, and breakage have been described in detail, chemical reactions affecting flow properties have received less attention. Such chemical reactions include the precipitation of carbonate and quartz cement, dissolution and albitization of feldspar, and the neoformation and infiltration of clay minerals. It is shown that the mechanical process of deformation localization is strongly controlled by chemical processes including pre-kinematic pore-filling cement, syn-kinematic cement filling intra- and transgranular fractures, and stress-enhanced dissolution reactions. Prekinematic cements reduce the strength contrast between grain and aggregate thus favoring deformation localization into narrow, well defined deformation bands. Prekinematic cementation and compaction may even favor thoroughgoing opening mode fractures and prevent localization of deformation into deformation band. Synkinematic cements within deformation bands will result in local strain hardening of bands and thus oppose further deformation localization with increasing strain. Examples will be presented from the Mesozoic clastic sequence of the western US to illustrate these processes.

  4. Structure and properties of copper after large strain deformation

    Energy Technology Data Exchange (ETDEWEB)

    Rodak, Kinga; Molak, Rafal M.; Pakiela, Zbigniew

    2010-05-15

    Structure and properties of Cu in dependence on strain (from {epsilon}{proportional_to} 0.9 to {epsilon}{proportional_to} 15) during multi-axial compression processing at room temperature was investigated. The evolution of dislocation structure, misorientation distribution and crystallite size were observed by using transmission electron microscopy (TEM) and scanning electron microscopy (SEM) equipment with electron back scattered diffraction (EBSD) facility. The mechanical properties of yield strength (YS), ultimate tensile strength (UTS) and uniform elongation was performed on MTS QTest/10 machine equipped with digital image correlation method (DIC). The structure-flow stress relationship of multi-axial compression processing material at strains {epsilon}{proportional_to} 3.5 and {epsilon}{proportional_to} 5.5 is discussed. It is found that processing does not produce any drastic changes in deformation structure and the microstructural refinement is slow. These results indicate that dynamic recrystallization plays an important role during multi-axial compression process in this range of deformation (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. Neoclassical currents in the Wisconsin Levitated Octupole

    International Nuclear Information System (INIS)

    Neoclassical transport theory predicts the existence of bootstrap current in collisionless plasmas with a significant population of trapped particles. This unidirectional current flows along field lines, and is generated by the balancing of ion-electron friction forces with the viscous forces between trapped and untrapped like particles. The current is driven by gradients in the plasma pressure and temperature. Previous work has identified the existence of bootstrap current in the Wisconsin Levitated Octupole, and this discovery of bootstrap current in the octupole naturally leads to the question of why previous experiments were unsuccessful in their endeavors to identify this current. The original motivation for this thesis was to address that question, by investigating the effects on bootstrap current caused by ohmic currents, plasma fluctuations, and rf fields. Ohmic currents, while naturally present in tokamaks, can be introduced in the octupole, independent of the usual operating procedure, and can be adjusted to be of the same order of magnitude as the expected diamagnetic and parallel currents. The interaction, if any, of bootstrap current and ohmic current can thus be determined without the problem of a large ohmic current masking the neoclassical current. Rf fields can be driven in the octupole plasma with little or no plasma heating. Any anomalous effects on the parallel currents, due to the existence of the rf fields, can then be determined. This thesis consists of four parts: the experimental apparatus and the plasma diagnostics used in these studies; the general theory of neoclassical currents (excluding field errors) and how it is applied to the octupole; the experimental results of this investigation; and a brief discussion of the conclusions that can be inferred from the data

  6. Evidence for octupole vibration in the superdeformed well of 190Hg from eurogam

    International Nuclear Information System (INIS)

    Gammasphere experiments in 1993-94 brought to light the existence of an excited superdeformed (SD) band in 190Hg with the unusual property of decaying entirely to the lowest (yrast) SD band over 3-4 transitions, rather than to the normally deformed states as is usually the case in the A ? 150 and A ? 190 regions of superdeformation. Although M1 transitions between signature-partner SD bands were previously observed in 193Hg, no such mechanism was available to explain the situation in the even-even nucleus 190Hg, whose yrast SD band has no signature partner. The best explanation appears to lie in long-standing theoretical predictions that the SD minimum in the potential energy surface would be quite soft with respect to octupole vibrations. This would lead to enhanced E1 transitions connecting the one-phonon and zero-phonon states. The data and this interpretation were published. A shortcoming of the Gammasphere experiments was that they did not allow the definitive measurement of the energies of the gamma-ray transitions connecting the two bands, due to the very weak population of the excited band (?0.05% of the 190Hg channel) and also partly, we believed, to the angular distributions of the transitions, which were peaked near 90 degrees, where Gammasphere had few detectors

  7. Observation of octupoles states in the fission probability of different thorium isotopes

    International Nuclear Information System (INIS)

    Sharp resonances are observed in the fission probability of 230Th, 231Th and 233Th, measured in the (n,f) and (d,pf) reactions below the fission threshold. A simultaneous analysis of these resonances and of the associated fission fragment angular distributions concludes to the presence of two superimposed bands of levels, with a very large moment of inertia. These levels are interpreted as the lower levels in the ''third well'', predicted by the calculations to occur, at large quadrupole deformation and non-vanishing octupole deformation, in the potential energy surface of the light actinides

  8. Octupole bands and simplex inversion in the neutron-rich nucleus 145Ba

    Science.gov (United States)

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

    2015-01-01

    The issue of the existence of reflection asymmetry in 145Ba has stood for the past 30 years without a common conclusion. The recent experimental data show a number of low-lying rotational bands with alternative parities, providing more strict constraints on the relevant modeling. With a proper octupole deformation, all the observed six rotational bands in 145Ba have been well reproduced by the reflection asymmetric shell model (RASM). The three octupole deformed neutron single-particle orbitals just above the octupole shell gap 88, with K =1 /2 ,K =3 /2 , and K =5 /2 , respectively, dominate the intrinsic configurations of the observed bands. Based on the analysis of the calculated RASM wave functions, the assignments for the observed bands have been given. The experimental yrast band (? I =1 ) presents a simplex inversion at around the 11 /2- state where the simplex staggering phase changes. This phenomenon may be explained in the framework of the RASM as from the change of the dominate intrinsic configuration, induced by the band mixing. The present results strongly support the appearance of the reflection asymmetry in the ground and low-lying states of 145Ba.

  9. Semiclassical analysis of the lowest-order multipole deformations of simple metal clusters

    Science.gov (United States)

    Pashkevich, V. V.; Meier, P.; Brack, M.; Unzhakova, A. V.

    2002-03-01

    We use a perturbative semiclassical trace formula to calculate the three lowest-order multipole (quadrupole ?2, octupole ?3, and hexadecapole ?4) deformations of simple metal clusters with 90? N?550 atoms in their ground states. The self-consistent mean field of the valence electrons is modeled by an axially deformed cavity and the oscillating part of the total energy is calculated semiclassically using the shortest periodic orbits. The average energy is obtained from a liquid-drop model adjusted to the empirical bulk and surface properties of the sodium metal. We obtain good qualitative agreement with the results of quantum-mechanical calculations using Strutinsky's shell-correction method.

  10. Observation of Octupole Structures in Radon and Radium Isotopes and Their Contrasting Behavior at High Spin

    International Nuclear Information System (INIS)

    Multinucleon transfer reactions have been used, for the first time, to populate high-spin bands of alternating parity states in 218,220,222Rn and 222,224,226Ra. The behavior of the angular momentum alignment with rotational frequency for the Rn isotopes is very different when compared with Ra and Th isotopes with N?134, indicating a transition from octupole vibrational to stable octupole deformation. Throughout the measured spin range the values of |D0/Q0| remain constant for 222Ra and 226Ra and have a very small value for 224Ra, suggesting that the charge and mass distributions are not affected appreciably by rotations. copyright 1997 The American Physical Society

  11. Transient deformation properties of Zircaloy for LOCA simulation. Final report

    International Nuclear Information System (INIS)

    The creep/creep rupture anisotropic properties of Zircaloy were determined and compared by analytical techniques with ramp-pressure and ramp-temperature test results. Tests were performed over the temperature range of 6000F (5890K) to 22000F (14770K) with the emphasis on the 8000F (7000K) to 20000F (13660K) temperature levels in low pressure air (6.5 x 10-5 atm) and in a 1 atm mixture of 20% oxygen, 80% argon. Stress levels of 60 to 95% of the ultimate tensile stress were used for the majority of the tests at each of the temperature levels tested, with selected tests performed as low as 30% of the ultimate tensile stress. Biaxial and uniaxial testing modes were used to evaluate the anisotropic deformation behavior. The combination of test results and predictive analysis techniques developed as part of this program make it possible to predict the transient deformation of reactor fuel cladding during simulated LOCA conditions. Results include creep/creep rupture strain numerical constitutive relationships out of 120 seconds, computer codes and ramp test data

  12. Chiral symmetry restoration and pion properties in a q-deformed NJL model

    Scientific Electronic Library Online (English)

    V. S., Timóteo; C. L., Lima.

    2006-03-01

    Full Text Available SciELO Brazil | Language: English Abstract in english We review the implementation of a q-deformed fermionic algebra in the Nambu-Jona-Lasinio model (NJL). The gap equations obtained from a deformed condensate as well as from the deformation of the NJL Hamiltonian are discussed. The effect of both temperature and deformation in the chiral symmetry rest [...] oration process as well as in the pion properties is studied.

  13. Fluid and ionic transport properties of deformed salt rock

    International Nuclear Information System (INIS)

    This is a final report on work done on the transport properties of salt during the period 1 January 1984 to 30 June 1985. This work was directed largely at the measurement of creep-induced permeability in salt rock, at determining the permeability persistence/decay characteristics of creep-dilated salt rock under hydrostatic conditions, and at ion migration/retention experiments on both deformed and undeformed material. The permeability work was carried out using both gas (argon) and brine, and involved the design and construction of corresponding permeametry systems for use in conjunction with dilatometric triaxial testing apparatus. Ion migration/retention studies involved the use of contaminant species such as Sr2+, Cs+, Fe3+ and TcO4

  14. Spin assignment of the lowest octupole bandhead in 236U

    International Nuclear Information System (INIS)

    Measurements carried out to determine the nature of the octupole bandhead in 236U led in the past to considerable confusion concerning its spin assignment. To see whether penetration effects are important in the conversion electron decay of the octupole band, a high resolution measurement was carried out at the #betta#-spectrometer of the ILL. Relative intensities have been determined for the transitions from the octupole bandhead to the O+, 2+ and 4+ members of the ground state rotational. (U.K.)

  15. Some Electronic Properties of Metals through q-Deformed Algebras

    CERN Document Server

    Tristant, Damien

    2013-01-01

    We study the thermodynamics of metals by applying q-deformed algebras. We shall mainly focus our attention on q-deformed Sommerfeld parameter as function of q-deformed electronic specific heat. The results revealed that q-deformation acts as a factor of disorder or impurity, modifying the characteristics of a crystalline structure and thereby controlling the number of electrons per unit volume.

  16. Deformation-induced microstructures: analysis and relation to properties

    International Nuclear Information System (INIS)

    The formation of microstructures is a unifying theme in the wide spectrum of materials behaviour associated with plastic deformation. Thus microstructures are generated during monotonic and cyclic deformation at low and high temperatures as well as during creep. Microstructures forming locally at crack fronts play critical roles in fatigue and fracture. It is becoming increasingly clear that deformation-induced microstructures are far more diversified than previously assumed. These deformation-induced microstructures define the theme of the present symposium. (LN)

  17. Influence of the initial grain size and deformation parameters on the mechanical properties during hot plastic deformation of austenitic steels

    International Nuclear Information System (INIS)

    The influence of the initial grain size and plastic deformation parameters on the mechanical properties during hot tension test has been analysed. As a material for the research has been chosen a Cr-Mn austenitic steel of 17/17 grade, as well as Cr-Ni austenitic steel (18/9) the chemical composition of which is similar to that of AIS1304. In the whole range of the determined plastic flow of the samples of both steel grades, the size of grain created in the result of dynamic recrystallization practically does not depend on the ? deformation size, but only on deformation conditions (T, ?). Practically the same grain sizes regardless the initial grain size of the tested austenitic steel grades were obtained during dynamic recrystallization at the temperatures of 1000 - 1100 oC. There are mathematical dependencies between deformation conditions (T, ?), sizes of grain and subgrain created during dynamic recrystallization Ds (or As) and stress ?s (or ?pmax) which can constitute the basis while modelling the process of microstructure changes during hot deformation. In this work are elaborated the functional relations representing the influence of initial grain size and plastic deformation parameters onto technical properties of austenitic steels. Besides, there is defined by means of statistic tests a rate of influence of individual parameters onto the values of ?pmax and ?pmax received from and ?pmax received from hot tension test. In samples of Cr-Mn and Cr-Ni steels subjected to deformation temperature 1000 oC and higher, for the whole analysed range of torsion speeds, after surpassing the deformation ?pmax the stress becomes fixed at steady level ?s. (author)

  18. Nuclear Schiff moment in nuclei with soft octupole and quadrupole vibrations

    CERN Document Server

    Auerbach, N; Flambaum, V V; Lisetskiy, A; Senkov, R A; Zelevinsky, V G

    2006-01-01

    Nuclear forces violating parity and time reversal invariance (${\\cal P},{\\cal T}$-odd) produce ${\\cal P},{\\cal T}$-odd nuclear moments, for example, the nuclear Schiff moment. In turn, this moment can induce the electric dipole moment in the atom. The nuclear Schiff moment is predicted to be enhanced in nuclei with static quadrupole and octupole deformation. The analogous suggestion of the enhanced contribution to the Schiff moment from the soft collective quadrupole and octupole vibrations in spherical nuclei is tested in this article in the framework of the quasiparticle random phase approximation with separable quadrupole and octupole forces applied to the odd $^{217-221}$Ra and $^{217-221}$Rn isotopes. We confirm the existence of the enhancement effect due to the soft modes. However, in the standard approximation the enhancement is strongly reduced by a small weight of the corresponding "particle + phonon" component in a complicated wave function of a soft nucleus. The perspectives of a better description...

  19. Nonclassical Properties of Q-Deformed Superposition Light Field State

    Science.gov (United States)

    Ren, Min; Shenggui, Wang; Ma, Aiqun; Jiang, Zhuohong

    1996-01-01

    In this paper, the squeezing effect, the bunching effect and the anti-bunching effect of the superposition light field state which involving q-deformation vacuum state and q-Glauber coherent state are studied, the controllable q-parameter of the squeezing effect, the bunching effect and the anti-bunching effect of q-deformed superposition light field state are obtained.

  20. Microscopic description of octupole-phonon alignment in the actinides

    Energy Technology Data Exchange (ETDEWEB)

    Nazmitdinov, R.G.

    1987-09-01

    A microscopic model, based on an approach that combines the ideas of the cranking model and the random-phase approximation, is formulated for the description of the vibrational octupole states. The mean field is approximated by a rotating Nilsson potential with allowance for monopole pairing. The residual interaction is made up of separable octupole--octupole interactions of the isoscalar and isovector types with negative signature. An empirical formula establishing a relation between the vibrational excitation energy and the aligned vibrational angular momentum as a function of the angular velocity is proposed. The alignment of the vibrational octupole angular momentum for the states of the K/sup ..pi../ = 0/sup -/ band of the /sup 230,232/Th and /sup 238/U nuclei is analyzed. A qualitative correspondence of the nature of the branching of the electric dipole transitions from the octupole states into the yrast-line states in these nuclei is obtained.

  1. Microscopic description of the octupole phonon alignment in actinides

    International Nuclear Information System (INIS)

    The microscopic model based on the cranking random phase approximation for the description of the vibrational octupole states is formulated. The average field is approximated by the rotating nilsson potential witn monopole pairing. The hamiltonian of the model contains both isoscalar and isovector components of the separable octupole-octupole interaction of the negative signature. The empirical relation between the excitation energy and aligned angular momentum of the vibrational state from the dependence of the angular frequency is suggested. The alignment of the vibrational octupole angular momentum in the states of the Kn=0- band of 238U and 230,232Th is analysed. A qualitative correspondence of the behaviour of the branching of dipole electric transitions for these nuclei from the octupole states to the yrast states is obtained

  2. Microscopic description of octupole-phonon alignment in the actinides

    International Nuclear Information System (INIS)

    A microscopic model, based on an approach that combines the ideas of the cranking model and the random-phase approximation, is formulated for the description of the vibrational octupole states. The mean field is approximated by a rotating Nilsson potential with allowance for monopole pairing. The residual interaction is made up of separable octupole--octupole interactions of the isoscalar and isovector types with negative signature. An empirical formula establishing a relation between the vibrational excitation energy and the aligned vibrational angular momentum as a function of the angular velocity is proposed. The alignment of the vibrational octupole angular momentum for the states of the K/sup ?/ = 0- band of the /sup 230,232/Th and /sup 238/U nuclei is analyzed. A qualitative correspondence of the nature of the branching of the electric dipole transitions from the octupole states into the yrast-line states in these nuclei is obtained

  3. Indication of an octupole shape revealed in the (tau,?) population of high-spin states in 225Ra

    International Nuclear Information System (INIS)

    High spin states in 225Ra have been populated in the (tau,?) reaction with a 30 MeV3 He beam. Levels associated with the jsub(15/2) intruder orbital are given special attention. The peculiar population pattern observed for such states, located at excitation energies of 274 and 538 keV in 225Ra, is predicted in a model calculation where an octupole deformation is assumed. (orig.)

  4. Crystallization of ion clouds in octupole traps: structural transitions, core melting, and scaling laws

    OpenAIRE

    Calvo, Florent; Champenois, Caroline; Yurtsever, Ersin

    2009-01-01

    The stable structures and melting properties of ion clouds in isotropic octupole traps are investigated using a combination of semi-analytical and numerical models, with a particular emphasis at finite size scaling effects. Small-size clouds are found to be hollow and arranged in shells corresponding approximately to the solutions of the Thomson problem. The shell structure is lost in clusters containing more than a few thousands of ions, the inner parts of the cloud becomin...

  5. ICRH experiments in a toroidal octupole

    International Nuclear Information System (INIS)

    A 100 kW, 144 ?sec pulse of 1.4 MHz rf is used to heat plasmas with densities less than or equal to 3 x 1012 cm-3 at the ion cyclotron frequency in a toroidal octupole. The rf is coupled to the plasma by a single turn, electrostatically shielded hoop coaxial to the four main hoops and located near the wall. Absorbed power is inferred from plasma loading of the hoop and measured directly with an electrostatic ion energy analyzer and compared to single particle resonance heating theory

  6. Effect of deformation rate on the mechanical properties of arteries

    OpenAIRE

    Hatzikiriakos, Savvas G.; Sebastien Delorme; Robert DiRaddo; Vincent Mora; Virues Delgadillo, Jorge O.

    2010-01-01

    Pig aorta samples were tested uniaxially and equi- biaxially at deformation rates from 10 to 200 %/s. Under uniaxial and biaxial testing, loading forces were reduced up to 20% when the deformation rate was increased from 10 to 200 %/s, which is the opp- osite to the behaviour seen in other biological tissues. A rate-dependent isotropic hyperelastic constitutive equation, derived from the Mooney-Rivlin model, was fitted to the experimental results (e.g. aorta specimens) using an inverse finite...

  7. Deformation effect on properties and fine structure of invar

    International Nuclear Information System (INIS)

    Determined is deformation effect (with degrees of 10, 30, 50 %) before standard heat treatment (hardening from 830 deg C + tempering at 315 deg C + ageing at 95 deg C 48 hrs) on the temperature coefficient of linear expansion ?, coercive force, hardness and fine invar structure (the region of coherent scattering and microdistortions). It is found that the degree of deformation considerably affects Hsub(c), HV and substructural invar characteristics, the 10% reduction decreases ? in the course of standard heat treatment

  8. Spectroscopy of quadrupole and octupole states in rare-earth nuclei from a Gogny force

    CERN Document Server

    Nomura, K; Robledo, L M

    2015-01-01

    Collective quadrupole and octupole states are described in a series of Sm and Gd isotopes within the framework of the interacting boson model (IBM), whose Hamiltonian parameters are deduced from mean field calculations with the Gogny energy density functional. The link between both frameworks is the ($\\beta_2\\beta_3$) potential energy surface computed within the Hartree-Fock-Bogoliubov framework in the case of the Gogny force. The diagonalization of the IBM Hamiltonian provides excitation energies and transition strengths of an assorted set of states including both positive and negative parity states. The resultant spectroscopic properties are compared with the available experimental data and also with the results of the configuration mixing calculations with the Gogny force within the generator coordinate method (GCM). The structure of excited $0^{+}$ states and its connection with double octupole phonons is also addressed. The model is shown to describe the empirical trend of the low-energy quadrupole and o...

  9. Changes in microstructure and physical properties of skutterudites after severe plastic deformation.

    Czech Academy of Sciences Publication Activity Database

    Rogl, G.; Grytsiv, A.; Buršík, Ji?í; Horky, J.; Anbalagan, R.; Bauer, E.; Mallik, R.Ch.; Rogl, P.; Zehetbauer, M.

    2015-01-01

    Ro?. 17, ?. 5 (2015), s. 3715-3722. ISSN 1463-9076 Institutional support: RVO:68081723 Keywords : physical properties * plastic deformation * TEM, SEM Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.198, year: 2013

  10. Mechanical properties and structure of powder deformed tungsten-rhenium alloys

    International Nuclear Information System (INIS)

    Mechanical properties and structure of tungsten alloys deformed with percent reduction of 80% are studied. Mechanical properties and structure of technically pure tungsten are presented for comparison. It is established that mechanical properties of rhenium (2% by mass) alloyed tungsten alloy are higher than those of pure tungsten and tungsten alloy with oxide additions of yttrium and hafnium

  11. 316L austenite steel microstructure and properties after severe plastic deformation

    International Nuclear Information System (INIS)

    The results obtained on the nanocrystalline austenitic stainless steels 316L are presented. The nanostructure was obtained by large deformation through the torsion under high pressure (HTP) to the logarithmic deformation value of ? ? 10 - 11. Mechanical properties and microstructure were investigated in the as deformed material. It has been shown that applied process reduces the grain size to approximately 60 nm. Measurements of hardness and tensile tests showed that HPT process increases significantly desired properties of nanocrystalline austenitic steel. Thermal stability of nanocrystalline structures has also been investigated. (author)

  12. Microstructure, texture and superconducting properties of Bi2212 ceramics, deformed by torsion under pressure

    Energy Technology Data Exchange (ETDEWEB)

    Imayev, M.F. [Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstrasse 8-10, A-1040 Vienna (Austria); Institute for Metals Superplasticity Problems, Russian Academy of Sciences, Khalturina 39, Ufa 450001 (Russian Federation)], E-mail: marcel@imsp.da.ru; Daminov, R.R. [Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstrasse 8-10, A-1040 Vienna (Austria); Institute for Metals Superplasticity Problems, Russian Academy of Sciences, Khalturina 39, Ufa 450001 (Russian Federation); Reissner, M.; Steiner, W. [Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstrasse 8-10, A-1040 Vienna (Austria); Makarova, M.V.; Kazin, P.E. [Chemistry Department, Moscow State University, Moscow 119992 (Russian Federation)

    2007-12-01

    A systematic investigation of the effect of high-temperature deformation by torsion under quasi-hydrostatic pressure on the microstructure, texture and superconducting properties of Bi2212 ceramics was carried out. Intercolony sliding was identified as the main mechanism of plastic deformation and basal texture formation. In all investigated deformation regimes the colony thickness did not change, only their length varied. The superconducting properties were analyzed as caused by the action of three main pinning centers: intracolonial lattice defects, low-angle colony boundaries and particles of secondary phases which appear during the decomposition of the Bi2212 phase near the melting point.

  13. String field theory. Algebraic structure, deformation properties and superstrings

    Energy Technology Data Exchange (ETDEWEB)

    Muenster, Korbinian

    2013-07-23

    This thesis discusses several aspects of string field theory. The first issue is bosonic open-closed string field theory and its associated algebraic structure - the quantum open-closed homotopy algebra. We describe the quantum open-closed homotopy algebra in the framework of homotopy involutive Lie bialgebras, as a morphism from the loop homotopy Lie algebra of closed string to the involutive Lie bialgebra on the Hochschild complex of open strings. The formulation of the classical/quantum open-closed homotopy algebra in terms of a morphism from the closed string algebra to the open string Hochschild complex reveals deformation properties of closed strings on open string field theory. In particular, we show that inequivalent classical open string field theories are parametrized by closed string backgrounds up to gauge transformations. At the quantum level the correspondence is obstructed, but for other realizations such as the topological string, a non-trivial correspondence persists. Furthermore, we proof the decomposition theorem for the loop homotopy Lie algebra of closed string field theory, which implies uniqueness of closed string field theory on a fixed conformal background. Second, the construction of string field theory can be rephrased in terms of operads. In particular, we show that the formulation of string field theory splits into two parts: The first part is based solely on the moduli space of world sheets and ensures that the perturbative string amplitudes are recovered via Feynman rules. The second part requires a choice of background and determines the real string field theory vertices. Each of these parts can be described equivalently as a morphism between appropriate cyclic and modular operads, at the classical and quantum level respectively. The algebraic structure of string field theory is then encoded in the composition of these two morphisms. Finally, we outline the construction of type II superstring field theory. Specific features of the superstring are the appearance of Ramond punctures and the picture changing operators. The sewing in the Ramond sector requires an additional constraint on the state space of the world sheet conformal field theory, such that the associated symplectic structure is non-degenerate, at least on-shell. Moreover, we formulate an appropriate minimal area metric problem for type II world sheets, which can be utilized to sketch the construction of a consistent set of geometric vertices. The algebraic structure of type II superstring field theory is that of a N = 1 loop homotopy Lie algebra at the quantum level, and that of a N = 1 homotopy Lie algebra at the classical level.

  14. String field theory. Algebraic structure, deformation properties and superstrings

    International Nuclear Information System (INIS)

    This thesis discusses several aspects of string field theory. The first issue is bosonic open-closed string field theory and its associated algebraic structure - the quantum open-closed homotopy algebra. We describe the quantum open-closed homotopy algebra in the framework of homotopy involutive Lie bialgebras, as a morphism from the loop homotopy Lie algebra of closed string to the involutive Lie bialgebra on the Hochschild complex of open strings. The formulation of the classical/quantum open-closed homotopy algebra in terms of a morphism from the closed string algebra to the open string Hochschild complex reveals deformation properties of closed strings on open string field theory. In particular, we show that inequivalent classical open string field theories are parametrized by closed string backgrounds up to gauge transformations. At the quantum level the correspondence is obstructed, but for other realizations such as the topological string, a non-trivial correspondence persists. Furthermore, we proof the decomposition theorem for the loop homotopy Lie algebra of closed string field theory, which implies uniqueness of closed string field theory on a fixed conformal background. Second, the construction of string field theory can be rephrased in terms of operads. In particular, we show that the formulation of string field theory splits into two parts: The first part is based solely on the moduli space of world sheets and ensures that the perturbative string amplitudes are recovered via Feynman rules. The second part requires a choice of background and determines the real string field theory vertices. Each of these parts can be described equivalently as a morphism between appropriate cyclic and modular operads, at the classical and quantum level respectively. The algebraic structure of string field theory is then encoded in the composition of these two morphisms. Finally, we outline the construction of type II superstring field theory. Specific features of the superstring are the appearance of Ramond punctures and the picture changing operators. The sewing in the Ramond sector requires an additional constraint on the state space of the world sheet conformal field theory, such that the associated symplectic structure is non-degenerate, at least on-shell. Moreover, we formulate an appropriate minimal area metric problem for type II world sheets, which can be utilized to sketch the construction of a consistent set of geometric vertices. The algebraic structure of type II superstring field theory is that of a N = 1 loop homotopy Lie algebra at the quantum level, and that of a N = 1 homotopy Lie algebra at the classical level.

  15. Tensile Properties and Deformation Characteristics of a Ni-Fe-Base Superalloy for Steam Boiler Applications

    Science.gov (United States)

    Zhong, Zhihong; Gu, Yuefeng; Yuan, Yong; Shi, Zhan

    2014-01-01

    Ni-Fe-base superalloys due to their good manufacturability and low cost are the proper candidates for boiler materials in advanced power plants. The major concerns with Ni-Fe-base superalloys are the insufficient mechanical properties at elevated temperatures. In this paper, tensile properties, deformation, and fracture characteristics of a Ni-Fe-base superalloy primarily strengthened by ?' precipitates have been investigated from room temperature to 1073 K (800 °C). The results showed a gradual decrease in the strength up to about 973 K (700 °C) followed by a rapid drop above this temperature and a ductility minimum at around 973 K (700 °C). The fracture surfaces were studied using scanning electron microscopy and the deformation mechanisms were determined by the observation of deformed microstructures using transmission electron microscopy. An attempt has been made to correlate the tensile properties and fracture characteristics at different temperatures with the observed deformation mechanisms.

  16. On the octupole excitation in 236U

    International Nuclear Information System (INIS)

    Measurements of the K, Lsub(I), Lsub(II) and Msub(I) conversion lines of the 687.7 keV transition in 236U are evaluated within the electron penetration formalism. The spin-parity assignment of the octupole-band-head is found to be 1- in accordance with reaction data, and an assignment of 2- to the 687.7 keV state is ruled out. The penetration matrix element vertical strokeetavertical stroke has the value of 13.5 for the K-shell and increases slightly for higher main shells. An estimate of the anomalous amplitudes is compared with values reported for transitions in the odd even actinide nuclei. Furthermore electron conversion data for the 1-->2+ and 1-->4+ transitions are given. Radioactivity 236U from 235U(n,e-); measured: conversion electron decay; deduced: conversion coefficients from K, L and M shells; evaluated: dynamic matrix elements. (orig.)

  17. Quadrupole-octupole coupled states in 112Cd

    International Nuclear Information System (INIS)

    Negative-parity excitations in the 2.5 MeV region in 112Cd have been investigated with the (n,n'? reaction. Several of these states exhibit enhanced B(E2) values for decay to the 31- octupole state, indicative of quadrupole-octupole coupled (2+x3-) structures. The B(E1) values observed are typically in the range of 1-5x10-4 W.u., irrespective of the final state. (author)

  18. Deformation

    Directory of Open Access Journals (Sweden)

    RahulPandit

    2014-06-01

    Full Text Available We carry out an extensive numerical study of the dynamics of spiral waves of electrical activation, in the presence of periodic deformation (PD in two-dimensional simulation domains, in the biophysically realistic mathematical models of human ventricular tissue due to (a ten-Tusscher and Panfilov (the TP06 model and (b ten-Tusscher, Noble, Noble, and Panfilov (theTNNP04 model. We first consider simulations in cable-type domains, in which we calculate the conduction velocity $CV$ andthe wavelength $\\lambda$ of a plane wave; we show that PD leads to a periodic, spatial modulation of $CV$ and a temporallyperiodic modulation of $\\lambda$; both these modulations depend on the amplitude and frequency of the PD. We then examine three types of initial conditions for both TP06 and TNNP04 models and show that the imposition of PD leads to a rich variety ofspatiotemporal patterns in the transmembrane potential including states with a single rotating spiral (RS wave, a spiral-turbulence (ST state with a single meandering spiral, an ST state with multiple broken spirals, and a state SA in which all spirals are absorbed at the boundaries of our simulation domain. We find, for both TP06 and TNNP04 models, that spiral-wave dynamics depends sensitively on the amplitude and frequency of PD and the initial condition. We examine how these different types of spiral-wave states can be eliminated in the presence of PD by the application of low-amplitude pulses on square and rectangular control meshes. We suggest specific experiments that can test the results of our simulations.

  19. Structure and properties of beryllium bronzes after plastic deformation with different reduction ratio

    International Nuclear Information System (INIS)

    Investigated was the effect of the deformation degrees of 10, 20, 30 and 40% upon the strength properties and the structure of beryllium bronzes with 1.9-2.5% beryllium for samples of band 0.3 mm thick. Also the dependence of the properties upon post-deformation conditions of ageing was studied. It was shown that maximum values of the elasticity limit and the microhardness are achieved for all degrees of deformation after ageing at 310-320 deg C for 2-3 hours. The greater the degree of deformation, the greater are the elasticity limit, the ultimate strength, the microhardness and the electric resistance. It was noted that the optimum grain size of 30-40 ?m is achieved if duration of prehardening heating is not more than 30 min

  20. Effect of High-Temperature Severe Plastic Deformation on Microstructure and Mechanical Properties of IF Steel

    Science.gov (United States)

    Jindal, Vikas; Rupa, P. K. P.; Mandal, G. K.; Srivastava, V. C.

    2014-06-01

    Extensive research work has been carried out on interstitial-free steel to understand its response to deformation; particularly, the behavior during severe plastic deformation (SPD). However, most of these studies were mainly undertaken in the ferritic regime. The present investigation reports the initial results of our attempt to employ accumulative roll bonding (ARB), one of the variants of SPD, at a high temperature (950 °C). A considerable grain refinement has been observed, which may be attributed to the severity of deformation and recrystallisation at high temperatures. Nanoindentation tests have been performed at various stages of ARB process to understand the evolution of mechanical properties.

  1. Effect of cold plastic deformation on the properties of semihard-magnetic alloys

    International Nuclear Information System (INIS)

    The effect of pass and overall reduction during cold plastic deformation on magnetic properties of the 25KKh15 and 25KFN14 iron-cobalt alloys has been studied. It has been found out that gamma-? transformation which intensity id defined by the deformation temperature occurs during the 25KFN14 and 25KKh15 alloy cold rolling. The pass reduction decrease fostering complete proceeding of #betta#-? transformation is equivalent to the increase of overall reduction

  2. Evolution of deformation texture and magnetic properties in a nanocrystalline nickel-20 wt% cobalt alloy

    Science.gov (United States)

    Madhavan, R.; Suwas, S.

    2015-03-01

    The evolution of crystallographic texture in a nanocrystalline nickel-20 wt% cobalt alloy has been investigated for deformation up to large strains. The effect of texture on magnetic properties has been evaluated. The material shows characteristic copper-type texture at large strain levels. Microstructural examinations indicate that the evolution of texture is assisted by deformation-induced grain growth. The values of saturation magnetization and coercivity have been correlated with the crystallographic texture and grain size.

  3. Tailoring dislocation structures and mechanical properties of nanostructured metals produced by plastic deformation

    DEFF Research Database (Denmark)

    Huang, Xiaoxu

    2009-01-01

    The presence of a dislocation structure associated with low-angle dislocation boundaries and interior dislocations is a common and characteristic feature in nanostructured metals produced by plastic deformation, and plays an important role in determining both the strength and ductility of the nanostructured metals. The dislocation structure can be modified by post-process annealing and deformation which points to new ways of optimizing the mechanical properties. Such ways are demonstrated and discussed

  4. Mathematical description of properties of a weakly deformed Gauss peak. 1

    International Nuclear Information System (INIS)

    The properties of the weakly deformed Gaussian peak are described by given formulas. The moment generating function and all the higher moments of this weakly deformed Gaussian peak density function are calculated by closed integrations. The density function is useful for the design of Maximum-Likelihood peak shape parameter estimators and the application of spectral techniques with multi-channel spectra. Numerical calculations use the well known Gaussian error integral and can be done by programmable microcomputers or programmable pocket calculators. (author)

  5. Estimating the mechanical properties of the brittle deformation zones at Olkiluoto

    International Nuclear Information System (INIS)

    In rock mechanics modelling to support repository design and safety assessment for the Olkiluoto site, it is necessary to obtain the relevant rock mechanics parameters, these being an essential pre-requisite for the modelling. The parameters include the rock stress state, the properties of the intact rock and the rock mass, and the properties of the brittle deformation zones which represent major discontinuities in the rock mass continuum. However, because of the size and irregularity of the brittle deformation zones, it is not easy to estimate their mechanical properties, i.e. their deformation and strength properties. Following Section 1 explaining the motivation for the work and the objective of the Report, in Sections 2 and 3, the types of fractures and brittle deformation zones that can be encountered are described with an indication of the mechanisms that lead to complex structures. The geology at Olkiluoto is then summarized in Section 4 within the context of this Report. The practical aspects of encountering the brittle deformation zones in outcrops, drillholes and excavations are described in Sections 5 and 6 with illustrative examples of drillhole core intersections in Section 7. The various theoretical, numerical and practical methods for estimating the mechanical properties of the brittle deformation zones are described in Section 8, together with a Table summarizing each method's advantages, disadvantages and utility in estimating the mechanical properties of the zones. We emphasise that the optimal approach to estimating the mechanical properties of the brittle deformation zones cannot be determined without a good knowledge, not only of each estimation method's capabilities and idiosyncrasies, but also of the structural geology background and the specific nature of the brittle deformation zones being characterized. Finally, in Section 9, a Table is presented outlining each method's applicability to the Olkiluoto site. A flowchart is included to indicate the proposed structure for a brittle deformation zone mechanical property estimation campaign, noting that the exact nature of future work will depend on the results of the ONKALO Prediction-Outcome studies and decisions on the rock mechanics work required to support the repository design. (orig.)

  6. Determination of the deformation properties of Søvind Marl

    DEFF Research Database (Denmark)

    GrØnbech, Gitte; Nielsen, Benjaminn Nordahl

    2010-01-01

    A serie of tests were made to determine the preconsolidation stresses, ??pc, and the consolidation modulus, K, of Søvind Marl, a fissured plastic tertiary clay. The fissures causes a decrease in the stiffness of the Søvind Marl, which can be mistaken for the decrease that happens when the effective stresses in the soil, ??, passes ??pc. The effects of the fissures are assessed, and an estimate of the stress level at which they will compress are made. During the consolidation tests, the effective stress level is raised to more then 24,000 kPa to get a comprehensive description of the preconsolidation of the soil. It is important to know how a strongly preconsolidated soil will deform when reloaded. The deformation parameters of the strongly preconlidated Søvind Marl is determined by unloading/reloading testing. It is found that the stiffness of the Søvind Marl depends of the plasticity index, and one conclusive expression of the consolidation modulus of the Søvind Marl can therefor not be given.

  7. Effect of bubble deformation on the properties of bubbly flows

    Science.gov (United States)

    Bunner, Bernard; Tryggvason, Grétar

    2003-11-01

    Direct numerical simulations of the motion of 27 three-dimensional deformable buoyant bubbles in periodic domains are presented. The full Navier Stokes equations are solved by a parallelized finite-difference/front-tracking method that allows a deformable interface between the bubbles and the suspending fluid and the inclusion of surface tension. The Eötvös number is taken as equal to 5, so that the bubbles are ellipsoidal, and the Galileo number is 900, so that the rise Reynolds number of a single bubble in an unbounded flow is about 26. Three values of the void fraction have been investigated: 2%, 6% and 12%. At 6%, a change in the behaviour of the bubbles is observed. The bubbles are initially dispersed homogeneously throughout the flow field and their average rise Reynolds number is 23. After the bubbles have risen by about 90 bubble diameters, they form a vertical stream and accelerate. The microstructure of the bubble suspension is analysed and an explanation is proposed for the formation of these streams. The results for the ellipsoidal bubbles are compared to the results for nearly spherical bubbles, for which the Eötvös number is 1 and the Galileo number is 900. The dispersion of the bubbles and the velocity fluctuations in the liquid phase are analysed.

  8. Cyclic deformation and dynamic compressive properties of copper bicrystals

    International Nuclear Information System (INIS)

    Cyclic deformation and dynamic compressive tests of three copper bicrystals were carried out on a Shimadzu servo-hydraulic testing machine and a split Hopkinson pressure bar (SHPB) apparatus respectively. The post-deformation dislocation structures, grain boundary (GB) serrations and adiabatic shear bands (ASBs) were examined using electron channeling contrast (ECC) imaging in a scanning electron microscope (SEM). After cyclic straining the secondary slip bands were activated near the GB forming a GB affected zone (GBAZ). Microstructures beneath it are dislocation labyrinth or irregular persistent slip bands (PSBs). The saturation stress at GBAZ was calculated to be higher than that in the grain interior. In dynamic compression, the formation of ASBs, was found to be promoted by the GB. Dynamic stress-strain curves were compared with each other for single crystals, bicrystals and polycrystals. Microstructures were also characterized with orientation imaging microscopy (OIM) by electron backscattering diffraction (EBSD) technique. It was found that relatively larger lattice rotations occurred across the ASBs than in the other regions, which can be deduced by the localization of simple shear along ASBs. No recrystallization was found in the ASBs or along GBs in the present circumstance

  9. Influence of dispersed particles on small and large deformation properties of concentrated caseinate composites

    OpenAIRE

    Manski, J. M.; Kretzers, I. M. J.; Brenk, S.; Goot, A. J.; Boom, R. M.

    2007-01-01

    Concentrated sodium caseinate composites (30% w/w in water), which contained either dispersed palm fat or glass spheres varying in size and surface properties were prepared in a Brabender Do-Corder kneader. The influence of the dispersed phase on the structural properties of the sodium caseinate composites was investigated using both small oscillating and large tensile deformations. Both experimental results and selected models showed that all measured properties were mainly influenced by the...

  10. Microstructures and Mechanical Properties of High-Mn TRIP Steel Based on Warm Deformation of Martensite

    Science.gov (United States)

    Guo, Zhikai; Li, Longfei; Yang, Wangyue; Sun, Zuqing

    2015-04-01

    High-Mn TRIP steel with about 5 wt pct Mn was prepared by a thermo-mechanical treatment based on warm deformation of martensite and subsequent short-time annealing in the intercritical region. The microstructural evolution and the mechanical properties of the used steel during such treatment were investigated. The results indicate that during warm deformation of martensite in the intercritical region, the decomposition of martensite was accelerated by warm deformation and the occurrence of dynamic recrystallization of ferrite led to the formation of equiaxed ferrite grains. Meanwhile, the reverse transformation of austenite was accelerated by warm deformation to some extent. During subsequent annealing in the intercritical region, static recrystallization of ferrite led to the increase in the fraction of equiaxed ferrite grains, and the formation of the reversed austenite was accelerated by the addition of the deformation-stored energy, while the stability of the reversed austenite was improved by the accelerated diffusions of C atoms and Mn atoms. As a whole, the mechanical properties of the used steel by the thermo-mechanical treatment based on warm deformation of martensite and subsequent short-time annealing in the intercritical region were comparable to the steels with similar compositions subjected to intercritical annealing for hours after cold rolling of martensite.

  11. RPA description of dipole oscillations in deformed sodium clusters

    International Nuclear Information System (INIS)

    Dipole oscillations of valence electrons in deformed sodium clusters are described within the random-phase-approximation method with the self-consistent separable residual forces (SRPA). The coupling of surface and volume modes are taken into account. The influence of octupole excitations taking place in deformed systems is also considered. The results obtained are in remarkable agreement with available data

  12. Effect of material property heterogeneity on biomechanical modeling of prostate under deformation.

    Science.gov (United States)

    Samavati, Navid; McGrath, Deirdre M; Jewett, Michael A S; van der Kwast, Theo; Ménard, Cynthia; Brock, Kristy K

    2015-01-01

    Biomechanical model based deformable image registration has been widely used to account for prostate deformation in various medical imaging procedures. Biomechanical material properties are important components of a biomechanical model. In this study, the effect of incorporating tumor-specific material properties in the prostate biomechanical model was investigated to provide insight into the potential impact of material heterogeneity on the prostate deformation calculations. First, a simple spherical prostate and tumor model was used to analytically describe the deformations and demonstrate the fundamental effect of changes in the tumor volume and stiffness in the modeled deformation. Next, using a clinical prostate model, a parametric approach was used to describe the variations in the heterogeneous prostate model by changing tumor volume, stiffness, and location, to show the differences in the modeled deformation between heterogeneous and homogeneous prostate models. Finally, five clinical prostatectomy examples were used in separately performed homogeneous and heterogeneous biomechanical model based registrations to describe the deformations between 3D reconstructed histopathology images and ex vivo magnetic resonance imaging, and examine the potential clinical impact of modeling biomechanical heterogeneity of the prostate. The analytical formulation showed that increasing the tumor volume and stiffness could significantly increase the impact of the heterogeneous prostate model in the calculated displacement differences compared to the homogeneous model. The parametric approach using a single prostate model indicated up to 4.8?mm of displacement difference at the tumor boundary compared to a homogeneous model. Such differences in the deformation of the prostate could be potentially clinically significant given the voxel size of the ex vivo MR images (0.3? × ?0.3? × ?0.3?mm). However, no significant changes in the registration accuracy were observed using heterogeneous models for the limited number of clinical prostatectomy patients modeled and evaluated in this study. PMID:25489840

  13. Spectroscopy and octupole coupling of high-spin states in 213Rn

    International Nuclear Information System (INIS)

    Excited states of 213Rn, up to spins of ? 55/2 ? and an excitation energy of ? 6 MeV, have been studied using ?-ray and electron spectroscopy following the reactions 208Pb(9Be,4n) and 204Hg(13C,4n). Eight isomeric states were identified and g-factors for five of these measured by the TDPAD technique. Several of the isomeric states decay by enhanced E3 transitions. The level scheme and electromagnetic properties of the isomers are compared with the results of semi-empirical shell-model calculations including calculations which explicitly account for the particle-octupole vibration coupling

  14. Crystallization of ion clouds in octupole traps: structural transitions, core melting, and scaling laws

    CERN Document Server

    Calvo, Florent; Yurtsever, Ersin

    2009-01-01

    The stable structures and melting properties of ion clouds in isotropic octupole traps are investigated using a combination of semi-analytical and numerical models, with a particular emphasis at finite size scaling effects. Small-size clouds are found to be hollow and arranged in shells corresponding approximately to the solutions of the Thomson problem. The shell structure is lost in clusters containing more than a few thousands of ions, the inner parts of the cloud becoming soft and amorphous. While melting is triggered in the core shells, the melting temperature unexpectedly follows the rule expected for three-dimensional dense particles, with a depression scaling linearly with the inverse radius.

  15. Crystallization of ion clouds in octupole traps: Structural transitions, core melting, and scaling laws

    International Nuclear Information System (INIS)

    The stable structures and melting properties of ion clouds in isotropic octupole traps are investigated using a combination of semianalytical and numerical models, with a particular emphasis at finite-size scaling effects. Small-size clouds are found to be hollow and arranged in shells corresponding approximately to the solutions of the Thomson problem. The shell structure is lost in clusters containing more than a few thousands of ions, the inner parts of the cloud becoming soft and amorphous. While melting is triggered in the core shells, the melting temperature follows the rule expected for three-dimensional dense particles, with a depression scaling linearly with the inverse radius.

  16. Mechanical properties and deformation of polycrystalline lithium orthosilicate

    International Nuclear Information System (INIS)

    Room-temperature strength, fracture toughness, Young's modulus, and thermal-shock resistance were determined for 68--98% dense lithium orthosilicate (Li4SiO4) specimens. In the low-density regime, both strength and fracture toughness were controlled by the density of the specimen. At high density, the strength depends on grain size. Young's modulus values ranged from 30--103 GPa at densities between 68 and 98% TD. A critical quenching temperature difference in the range of 150--170/degree/C was observed in thermal-shock tests of bar specimens. Steady-state creep tests indicated 90% dense Li4SiO4 fractures at T ? 800/degree/C before reaching steady state and deforms plastically at 900/degree/C. It is more creep-resistant at 900/degree/C than Li2O, about equal to Li2Zr)3, and less than LiA102. 13 refs., 4 figs., 1 tab

  17. Red Blood Cell Deformation Under Shear Flow: The Effect of Changing Cell Properties

    Science.gov (United States)

    Forsyth, Alison M.; Wan, Jiandi; Ristenpart, William D.; Stone, Howard A.

    2008-11-01

    The deformability of red blood cells plays a major role in the pathology of several diseases, including malaria, sickle cell anemia and spherocytosis. Moreover, deformations are believed to trigger the release of adenosine triphosphate, which helps regulate vascular tone and is consequently an important factor in various vascular diseases. Here we investigate single-cell viscoelastic responses to increased shear stress in poly(dimethylsiloxane) channels with a single constriction 2-4 times larger than a typical erythrocyte. These channels mimic arteriole-sized vessels, and have the advantage that the cell membrane is not in contact with the channel walls which have vastly different mechanical and material properties than living tissue. High-speed video and image analysis were used to quantify the trajectories and deformations of cells exposed to varied doses of diamide, a chemical known to ``rigidify'' erythrocytes. Our results show that (i) deformation is proportional to shear rate and (ii) the deformability of diamide-treated cells is greater than that of untreated cells. The latter is an unforeseen result because micropipette aspiration experiments have shown the opposite. We expect that the experimental procedure described here will be useful for characterizing the effect of different therapeutic agents on cellular deformability.

  18. Mechanical Properties of Copper Processed by Severe Plastic Deformation.

    Czech Academy of Sciences Publication Activity Database

    Kunz, Ludvík

    Rijeka : InTech, 2012 - (Collini, L.), s. 93-126 ISBN 978-953-51-0160-4 R&D Projects: GA ?R GAP108/10/2001 Keywords : copper * ultrafinegrained structure * fatigue properties * localization of cyclic plasticity Subject RIV: JL - Materials Fatigue, Friction Mechanics

  19. PROPERTIES AND NANOSTRUCTURES OF NANO-MATERIALS PROCESSED BY SEVERE PLASTIC DEFORMATION (SPD).

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Y. T. (Yuntian Theodore)

    2001-01-01

    Metallic materials usually exhibit higher strength but lower ductility after being plastically deformed by conventional techniques such as rolling, drawing and extrusion. In contrast, nanostructured metals and alloys processed by severe plastic deformation (SPD) have demonstrated both high strength and high ductility. This extraordinary mechanical behavior is attributed to the unique nanostructures generated by SPD processing. The combination of ultrafine grain size and high-density dislocations appears to enable deformation by new mechanisms not active in coarse-grained metals and alloys. These results demonstrate the possibility of tailoring the microstructures of metals and alloys by SPD to obtain superior mechanical properties. Nanostructured metals and alloys processed by SPD techniques have unique nanostructures not observed in nanomaterials synthesized by other techniques such as the consolidation of nanopowders. The SPD-generated nanostructures have many features related to deformation, including high dislocation densities, and high- and low-angle grain boundaries in equilibrium or nonequilibrium states. Future studies are needed to investigate the deformation mechanisms that relate the unique nanostructures with the superior mechanical properties exhibited by SPD-processed metals and alloys.

  20. Effects of Dehydration on the Viscoelastic Properties of Vocal Folds in Large Deformations

    OpenAIRE

    Miri, Amir K.; Barthelat, Franc?ois; Mongeau, Luc

    2012-01-01

    Dehydration may alter vocal fold viscoelastic properties, which may hamper phonation. The effects of water loss induced by an osmotic-pressure potential on vocal fold tissue viscoelastic properties were investigated. Porcine vocal folds were dehydrated by immersion in a hypertonic solution, and quasi-static and low-frequency dynamic traction tests were performed for elongations of up to 50%. Digital image correlation was used to determine local strains from surface deformations. The elastic m...

  1. Analysis of plastic properties of titanium alloys under severe deformation conditions in machining

    OpenAIRE

    Khaimovich, Alexander I.; Balaykin, Andrey V.

    2014-01-01

    The present paper presents a method of analysis of titanium alloys plastic properties under severe deformation conditions during milling with registration of the cutting force components Fx, Fy, Fz in real time using a special stand. The obtained constitutive relations in the form the Johnson-Cook law for stresses and dependence for a friction coefficient describing the titanium alloy VT9 plastic properties under simulate operating conditions.

  2. Application of Severe Plastic Deformation Techniques to Magnesium for Enhanced Hydrogen Sorption Properties

    OpenAIRE

    Daniel Fruchart; Jacques Huot; Nataliya Ye. Skryabina

    2012-01-01

    In this paper we review the latest developments in the use of severe plastic deformation (SPD) techniques for enhancement of hydrogen sorption properties of magnesium and magnesium alloys. Main focus will be on two techniques: Equal Channel Angular Pressing (ECAP) and Cold Rolling (CR). After a brief description of these two techniques we will discuss their effects on the texture and hydrogen sorption properties of magnesium alloys. In particular, the effect of the processing temperature in E...

  3. Ground state octupole correlation energies with effective forces

    CERN Document Server

    Robledo, Luis M

    2014-01-01

    The ground state octupole correlations energies obtained with the D1M variant of the Gogny force are analyzed in detail. First we consider the correlation energy gained at the mean field level by allowing reflection symmetry breaking. Next we consider the energy gain coming from symmetry (parity) restoration and finally we analyze the ground state correlation energy after configuration mixing with axially symmetric octupole states. We find that these correlations do not significantly affect the trends of binding energies and systematics near closed shells. In particular, the too-large shell gaps predicted by self-consistent mean field models are not altered by the correlations.

  4. Two-phonon octupole excitation in Gd-146

    OpenAIRE

    Caballero Ontanaya, Luis; Rubio, Berta; Kleinheinz, P.; Yates, S. W.; Algora, Alejandro; Dewald, A.; Fitzler, A.; Gadea, Andre?s; Jolie, J.; Julin, R.; Linnemann, A.; Lunardi, S.; Menegazzo, R.; Mo?ller, O.; Na?cher, Enrique

    2010-01-01

    Based on experimental evidence from the 144Sm(?,2n) reaction, the 3484.7-keV 6+ state in 146Gd is identified as the highest-spin member of the 3? ? 3? two-phonon octupole quartet. A previously unknown ? line of 1905.8 keV and E3 character feeding the 3? octupole state has been observed. These results represent the first observation of a 6+ ? 3? ? 0+ cascade of two E3 transitions in an even-even nucleus and provide strong support for the interpretation of the 6+ state as a two-...

  5. Large-Deformation Properties of Wheat Flour and Gluten Dough

    OpenAIRE

    Sliwinski, E. L.

    2003-01-01

    Keywords: Wheat, gluten protein, bread, puff pastry, flour dough, gluten dough,rheology,uniaxialextension, biaxial extension, fracture.Rheologicaland fracture properties of flour and glutendoughsfrom eight wheat cultivars were studied and related to gluten protein composition and baking performance in bread and puff pastry. For bothuniaxialand biaxial extension flour dough showed a more than proportional increase of stress with increasing strain, a phenomenon called strain hardening. Inuniaxi...

  6. Mechanical properties evaluations of an age hardenable martensitic steel deformed by equal channel angular pressing.

    Science.gov (United States)

    Nili-Ahmadabadi, M; Shirazi, H; Iranpour Mobarake, M; Poorganji, B; Hossein Nedjad, S; Furuhara, T

    2010-09-01

    Effect of severe plastic deformation by equal channel angular pressing on the mechanical properties of an age hardenable low carbon martensitic steel was investigated. Equal Channel angular pressing was carried out on the solution-annealed steel up to four passes at room temperature through the route Bc. Aging was carried out at 753 K for 2.4 ks. It was found that after four passes deformation, the microstructure is consist of fine grained high angle grain boundaries and lamellar dislocation cell block. The strength of steel is increased considerably while a increasing in elongation is revealed. PMID:21133170

  7. The property of ?-deformed statistics for a relativistic gas in an electromagnetic field: ? parameter and ?-distribution

    Science.gov (United States)

    Guo, Lina; Du, Jiulin; Liu, Zhipeng

    2007-08-01

    We investigate the physical property of the ? parameter and the ?-distribution in the ?-deformed statistics, based on Kaniadakis entropy, for a relativistic gas in an electromagnetic field. We derive two relations for the relativistic gas in the framework of ?-deformed statistics, which describe the physical situation represented by the relativistic ?-distribution function, provide a reasonable connection between the parameter ?, the temperature four-gradient and the four-vector potential gradient, and thus present for the case ??0 one clearly physical meaning. It is shown that such a physical situation is a meta-equilibrium state of the system, but has a new physical characteristic.

  8. The property of ?-deformed statistics for a relativistic gas in an electromagnetic field: ? parameter and ?-distribution

    International Nuclear Information System (INIS)

    We investigate the physical property of the ? parameter and the ?-distribution in the ?-deformed statistics, based on Kaniadakis entropy, for a relativistic gas in an electromagnetic field. We derive two relations for the relativistic gas in the framework of ?-deformed statistics, which describe the physical situation represented by the relativistic ?-distribution function, provide a reasonable connection between the parameter ?, the temperature four-gradient and the four-vector potential gradient, and thus present for the case ?0 one clearly physical meaning. It is shown that such a physical situation is a meta-equilibrium state of the system, but has a new physical characteristic

  9. The effect of ultrasonics on the strength properties of carbon steel processed by cold plastic deformation

    Science.gov (United States)

    Atanasiu, N.; Dragan, O.; Atanasiu, Z.

    1974-01-01

    A study was made of the influence of ultrasounds on the mechanical properties of OLT 35 carbon steel tubes cold-drawn on a plug ultrasonically activated by longitudinal waves. Experimental results indicate that: 1. The reduction in the values of the flow limit and tensile strength is proportional to the increase in acoustic energy introduced into the material subjected to deformation. 2. The diminution in influence of ultrasounds on tensile strength and flow rate that is due to an increased degree of deformation is explained by a reduction in specific density of the acoustic energy at the focus of deformation. 3. The relations calculated on the basis of the variation in the flow limit and tensile strength as a function of acoustic energy intensity was verified experimentally.

  10. Influence of deformation ageing treatment on microstructure and properties of aluminum alloy 2618

    International Nuclear Information System (INIS)

    The effects of deformation ageing treatment (DAT) on the microstructure and properties of aluminum alloy 2618 were investigated. The alloy was subjected to deformation ageing treatment which included solution treating at 535 deg. C quenching into water at room-temperature, cold rolling (10%) and further ageing to peak hardness level at 200 deg. C. The electron microscopic studies revealed that the treatment affects the ageing characteristics and the coarsening of ageing phase (S') at elevated-temperature. The dislocation-precipitate tangles substructure couldn't be found in alloy 2618. The tensile and hardness tests showed that deformation-ageing treatment causes a significant improvement in tensile strength and hardness to alloy 2618 at room- and elevated-temperature

  11. Mechanical properties of mammalian cells in suspension measured by electro-deformation

    International Nuclear Information System (INIS)

    We describe a planar, micro-fabricated device for generating fringing non-uniform electric fields. We used it to measure the mechanical properties of individual mammalian cells in suspension by deforming them in time-varying, non-uniform electric fields. Electrical stresses generated by the planar microelectrodes were used to trap and stretch cells, while cell deformation was observed using optical microscopy. Two distinct cell types were compared after fitting strain data with a three-parameter 'standard linear solid' model of visco-elasticity, and with a two-parameter power-law method. Chinese hamster ovary (CHO) cells were approximately twice as stiff as U937 human promonocytes, and CHO cells displayed an elastic behaviour with recovery of initial shape, while U937 strain data bore witness to plastic deformation. Our results demonstrate that electrical stresses generated by micro-fabricated electrodes permit mechanical characterization of distinct mammalian cell types.

  12. Anisotropy of seismic and mechanical properties of opalinus clay during triaxial and shear deformation

    International Nuclear Information System (INIS)

    Knowledge of the complex interacting processes of dilatancy and healing is of vital interest for a characterization of the long term behaviour of a repository, independently from rock type. Constitutive models are needed to describe the development of the EDZ during inelastic closure of excavations in geological formations. They are typically expressed in terms of elastic constants, temperature, stress invariants, humidity, and empirical fitting parameters, assuming, at least, isotropic conditions. However, especially argillaceous rocks are inherently anisotropic. Depending on progressive compaction and a transformation of the originally deposited clay into an over-consolidated clay, clay stone or shale, the rocks become progressively foliated parallel to the bedding due to the sheet structure of the rock forming clay minerals. Although such planar discontinuities can act as preferential flow paths and play an important role on the initiation of inelastic deformation their impact on transport properties and deformation has been largely overlooked. While elastic deformation is usually more or less isotropic, initiation of inelastic deformation and the relative dilatation are clearly a function of bedding plane properties, the spatial orientation and stress geometry. These overlapping effects are particularly important during rock stress redistribution in the EDZ. Amongst others, this laboratory study will focus on the impact of mechanical properties of argillaceous roc mechanical properties of argillaceous rocks on the transport properties with respect to the bedding plane. The points of interest are subdivided in the following tasks: (1) Anisotropy of mechanical and transport properties referred to the bedding plane (2) Onset of dilatancy and its evolution (healing and damage) (3) Mechanical strength of the bedding plane direct shear strength testing. (authors)

  13. Low-temperature acoustic and thermal properties of plastically deformed, high-purity polycrystalline aluminum

    International Nuclear Information System (INIS)

    The low-temperature internal friction Q-1, thermal conductivity ?, specific heat cp and heat release of plastically deformed, high-purity aluminum polycrystals have been investigated and have been compared with measurements on an amorphous SiO2 specimen. Plastic deformation has a pronounced effect on both internal friction Q-1 and thermal conductivity ? in the superconducting state. The magnitude of the internal friction Q-1 can be increased over two orders by plastic deformation over that observed on an annealed sample, and approaches a value approximately equal to that of the amorphous SiO2 specimen. The lattice thermal conductivity ? of the deformed specimens also has a magnitude which is of the same order as that of amorphous SiO2, it is, however, nearly independent of the amount of deformation. No ''glass-like'' anomalies could be observed in the specific heat cp and heat release measurements. The specific heat cp approaches a T3-relationship at the lowest temperatures investigated, and heat release experiments clearly show no long-time energy relaxation effects. Thus, it must be concluded that the defects introduced into deformed aluminum cannot be described with the tunneling model which had been proposed to describe the low temperature elastic and thermal properties of amorphous solids and which is based on the assumption of a constant spectral dens assumption of a constant spectral density of tunneling states. The phonon scattering mechanism observed in the deformed aluminum is tentatively related to the interaction of phonons with geometrical kinks in dislocations. (orig.)

  14. Microstructure, Properties and Atomic Level Strain in Severely Deformed Rare Metal Niobium

    Directory of Open Access Journals (Sweden)

    Mart SAARNA

    2012-12-01

    Full Text Available The mechanical and physical properties relationship from atomic level strain/stress causes dislocation density and electrical conductivity relationship, as well as crystallites deformation and hkl-parameter change in the severely deformed pure refractory rare metal Nb at ambient temperature and during short processing times. The above mentioned issues are discussed in this study. For ultrafine-grained and nanocrystalline microstructure forming in metal the equal-channel angular pressing and hard cyclic viscoplastic deformation were used. The flat deformation and heat treatment at different parameters were conducted as follows. The focused ion beam method was used for micrometric measures samples manufacturied under nanocrystalline microstructure study by transmission electron microscope. The microstructure features of metal were studied under different orientations by X-ray diffraction scattering method, and according to the atomic level strains, dislocation density, hkl-parameters and crystallite sizes were calculated by different computation methods. According to results the evolutions of atomic level strains/stresses, induced by processing features have great influence on the microstructure and advanced properties forming in pure Nb. Due to cumulative strain increase the tensile stress and hardness were increased significantly. In this case the dislocation density of Nb varies from 5.0E+10 cm–2 to 2.0E+11 cm–2. The samples from Nb at maximal atomic level strain in the (110 and (211 directions have the maximal values of hkl-parameters, highest tensile strength and hardness but minimal electrical conductivity. The crystallite size was minimal and relative atomic level strain maximal in (211 orientation of crystal. Next, flat deformation and heat treatment increase the atomic level parameters of severely deformed metal.DOI: http://dx.doi.org/10.5755/j01.ms.18.4.3091

  15. Mechanical properties and structure of tungsten-rhenium powder metallurgy deformed alloys

    Energy Technology Data Exchange (ETDEWEB)

    Podrezov, Yu.N.; Radchenko, O.G.; Danilenko, N.G.; Panichkina, V.V.; Gachegov, V.I.; Ol' shanskii, A.B.

    1988-01-01

    The properties of tungsten-rhenium alloys, obtained by compact sintering of dispersed powders which formed a tungsten-rhenium solid solution at relatively low temperatures, were investigated. Three systems were compared: a tungsten alloy with 2% rhenium, an alloy with dispersed additions of yttrium and hafnium oxides, and commercially pure tungsten. The properties included ductile-to-brittle transition temperature, bend strength, yield strength, and crack resistance. Structures were determined by scanning electron microscopy. Tungsten alloyed with small additions of rhenium possessed higher plasticity and in other mechanical properties was similar to cast and deformed alloys of the same composition.

  16. Fifth-order aberrations in magnetic quadrupole-octupole systems

    International Nuclear Information System (INIS)

    Explicit integral expressions are given for the fifth-order geometrical aberration coefficients in rectilinear magnetic quadrupole-octupole systems used for the transport of nonrelativistic charged particle beams. The numerical values of the fifth-order geometrical aberration coefficients for a rare earth cobalt (REC) quadrupole doublet are given as an example. 26 refs., 5 figs., 4 tabs

  17. Effect of Nb content on deformation behavior and shape memory properties of Ti–Nb alloys

    International Nuclear Information System (INIS)

    Highlights: ? Reorientation of martensite variants occurred by the deformation of the {1 1 1} type I and ?2 1 1? type II twins. ? Magnitude of twinning shear in Ti–20Nb is larger than that in Ti–23Nb. ? Ti–20Nb exhibited a higher stress for the reorientation of martensite variants when compared with Ti–23Nb. -- Abstract: Deformation behavior and shape memory properties of Ti–(20, 23) at.% Nb alloys in a single ?? martensite state were investigated. The Ti–20Nb alloy exhibited a higher stress for the reorientation of martensite variants when compared with the Ti–23Nb alloy. The recovery strain due to the shape memory effect in the Ti–20Nb alloy was smaller than that in the Ti–23Nb alloy. Transmission electron microscope (TEM) observation revealed that the reorientation of martensite variants occurred by the deformation of {1 1 1} type I and ?2 1 1? type II twins. The Nb content dependence of the deformation behavior and shape memory properties was discussed considering the magnitude of twinning shear of the twins

  18. Effects of plastic deformations on microstructure and mechanical properties of ODS-310 austenitic steel

    International Nuclear Information System (INIS)

    Highlights: ? We fabricated a 310 type ODS austenitic steel by the process of MA and HIP. ? Plastic deformations, including forging and hot rolling, were applied to samples. ? Fine Y-Ti-O particles dispersed in a relatively uniform way after forging. ? Ductility increased greatly after deformations, while strength decreased slightly. - Abstract: ODS-310 austenitic steel (Fe–25Cr–20Ni–0.35Y2O3–0.5Ti) was fabricated by the process of mechanical alloying and hot isostatic pressing. Plastic deformations, including forging and hot rolling, were applied to the as-hipped samples to improve the ductility. Microstructural evolutions in samples under different fabrication conditions were characterized by TEM. Tensile properties were tested at 23 °C and 700 °C. Dispersed oxide particles with sizes between 10 nm and 50 nm were characterized to be rich in Y–Ti–O. UTS and elongation of the as-hipped sample were 904 MPa and 11% respectively at 23 °C. Elongation increased two times after plastic deformations while there was only slight decrease in strength properties.

  19. Effects of deformation rates on mechanical properties of PP/SEBS blends

    Directory of Open Access Journals (Sweden)

    O. Balkan

    2011-07-01

    Full Text Available Purpose: The goal of this study is to examine effects of tensile deformation rates ( on tensile properties of polypropylene/poly(styrene-b-ethylene-co-butylene-b-styrene copolymer (PP/SEBS blends and to determine suitable for accurate and reliable evaluation of mechanical properties of the blends in accordance with the results of Izod impact tests.Design/methodology/approach: PP/SEBS blends containing ?e = 0, 2.5, 5 and 10 volume % of SEBS thermoplastic elastomer were compounded using a twin-screw extruder, and then moulded with an injection moulding machine. Morphology of PP/SEBS blends were analysed by scanning electron microscopy (SEM. Mechanical properties of the blends were investigated tensile and Izod impact tests. Tensile deformation rates 1= 1.67 ms–1 and 2 = 16.67 ms–1 were used to determine ultimate tensile properties.Findings: Morphological analyses revealed that SEBS elastomer particles were well-dispersed throughout PP matrix in irregular forms with a narrow size distribution and evidenced a two-phase system formation. At low deformation rate ( 1, PP and PP/SEBS blends did not fail during tensile tests despite maximum tensile deformation, ?max = 600%; therefore, tensile toughness (UT, stress and strain values at break point (?b and ?b of the blends were not determined. However, at high deformation rate ( 2, all specimens tested in this study failed; a slight decrease in ?b of the blends with SEBS elastomer was associated with a significant increase in ?b and UT. Strain-rate-sensitivity of PP/SEBS blends was promoted with SEBS elastomer.Research limitations/implications: Mechanical properties determined through high-velocity tests are beyond the scope of this study.Practical implications: of tensile testing machines is readily adjustable, while ?max of tensile testing machines is limited. Consequently, in order to evaluate reliably mechanical properties of ductile materials like PP/SEBS blends, must be so high that ductile materials can fail during tensile tests.Originality/value: Tensile testing at high strain rate 2 was concluded to be more suitable for evaluation of mechanical properties of PP/SEBS blends than that of at low strain rate.

  20. Reflection asymmetric deformation and clustering in heavy nuclei

    International Nuclear Information System (INIS)

    The relationship between the cluster properties of heavy nuclei and the appearance of low-lying collective negative-parity states in these nuclei is discussed. Energies of the cluster type np-nh particle-hole excited states, where n is the number of nucleons in a cluster; are calculated. It is shown that the energies of these states take minimal values in nuclei having low-lying collective 1'- states and ground-state alternating-parity rotational bands with ?I=1. The correlation between the difference of the quadrupole deformations in the potential energy minimum and at the barrier separating two octupole minima and the value of the angular momentum, at which parity splitting disappears, is studied

  1. Reflection asymmetric deformation and clustering in heavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Jolos, R.V.; Palchikov, V.; Pashkevich, V.V.; Unzhakova, A.V. [Dubna (Russian Federation). Joint Institute for Nuclear Research

    1997-09-01

    The relationship between the cluster properties of heavy nuclei and the appearance of low-lying collective negative-parity states in these nuclei is discussed. Energies of the cluster type np-nh particle-hole excited states, where n is the number of nucleons in a cluster; are calculated. It is shown that the energies of these states take minimal values in nuclei having low-lying collective 1`- states and ground-state alternating-parity rotational bands with {Delta}I=1. The correlation between the difference of the quadrupole deformations in the potential energy minimum and at the barrier separating two octupole minima and the value of the angular momentum, at which parity splitting disappears, is studied.

  2. Semiclassical analysis of the lowest-order multipole deformations of simple metal clusters

    CERN Document Server

    Pashkevich, V V; Brack, M; Unzhakova, A V

    2002-01-01

    We use a perturbative semiclassical trace formula to calculate the three lowest-order multipole (quadrupole $\\eps_2$, octupole $\\eps_3$, and hexadecapole $\\eps_4$) deformations of simple metal clusters with $90 \\le N \\le 550$ atoms in their ground states. The self-consistent mean field of the valence electrons is modeled by an axially deformed cavity and the oscillating part of the total energy is calculated semiclassically using the shortest periodic orbits. The average energy is obtained from a liquid-drop model adjusted to the empirical bulk and surface properties of the sodium metal. We obtain good qualitative agreement with the results of quantum-mechanical calculations using Strutinsky's shell-correction method.

  3. Microstructure and Local Mechanical Properties of Cu-Co Alloys after Severe Plastic Deformation.

    Czech Academy of Sciences Publication Activity Database

    Buršík, Ji?í; Buršíková, V.; Svoboda, Milan; Král, Petr; Dvo?ák, Ji?í; Skleni?ka, Václav

    Zurich : Trans Tech Publications, 2014 - (Pešek, L.; Zubko, P.), s. 100-103 ISBN 978-3-03785-876-9. ISSN 1013-9826. - (Key Engineering Materials. 586). [LMP 2012 International Conference on Local Mechanical Properties /9./. Levo?a (SK), 07.11.2012-09.11.2012] R&D Projects: GA ?R(CZ) GAP108/11/2260 Institutional support: RVO:68081723 Keywords : severe plastic deformation * electron microscopy * EBSD Subject RIV: JG - Metallurgy

  4. Effect of droplet-matrix interactions on large deformation properties of emulsion-filled gels

    OpenAIRE

    Sala, G.; Aken, G. A.; Cohen Stuart, M. A.; Velde, F.

    2007-01-01

    The aim of this work was to identify the effect of droplet¿matrix interactions on the large deformation properties of emulsion-filled gels. A study was carried out on the behavior in compression of gelatin, whey protein isolate (WPI) and ¿-carrageenan gels containing emulsions stabilized by different emulsifying agents (WPI, WPI aggregates, lysozyme, polyoxyethylenesorbitan monolaurate [Tween 20]) to control droplet¿matrix interactions. For gelatin gels, emulsions stabilized with WPI and l...

  5. Aluminium. II - A review of deformation properties of high purity aluminium and dilute aluminium alloys.

    Science.gov (United States)

    Reed, R. P.

    1972-01-01

    The elastic and plastic deformation behavior of high-purity aluminum and of dilute aluminum alloys is reviewed. Reliable property data, including elastic moduli, elastic coefficients, tensile, creep, fatigue, hardness, and impact are presented. Single crystal tensile results are discussed. Rather comprehensive reference lists, containing publications of the past 20 years, are included for each of the above categories. Defect structures and mechanisms responsible for mechanical behavior are presented. Strengthening techniques (alloys, cold work, irradiation, quenching, composites) and recovery are briefly reviewed.

  6. Effects of superplastic deformations on thermophysical properties of tetragonal zirconia polycrystals

    International Nuclear Information System (INIS)

    Neutron irradiation studies on superplastic zirconia-based ceramics are now in progress as an innovative basic project using the High-temperature Engineering Test Reactor (HTTR) in Japan. The characteristics of the zirconia-based engineering components, made through the formation of superplastic, may be strongly affected by their response to transient or steady-state heat flow. Reliable thermophysical properties such as the coefficients of thermal expansion and thermal conductivity are, therefore, needed to estimate and predict the influence of a high-temperature environment. Accordingly, one of this project's targets is to study the thermophysical properties of superplastic zirconia-based ceramics. The first stage of the research addresses the effects of superplastic deformations on the thermophysical properties of a typical superplastic ceramic, 3 mol% yttria-stabilised tetragonal zirconia polycrystals (3Y-TZP), in its un-irradiated state. First, superplastic tensile deformations were conducted on 3Y-TZP specimens under different conditions in order to obtain specimens with different microstructural characteristics. Afterwards, the following actions were taken: - Specific heat measurements were conducted on the specimens at temperatures ranging from 473 K to 1273 K. - The thermal diffusivity was measured using a laser flash method. The thermal conductivity was then calculated from the measured thermal diffusivity, specific heat and density. - The linear thermal expaeat and density. - The linear thermal expansion was measured by a push-rod type dilatometer from 300 K to 1473 K. The coefficient of linear thermal expansion (CTE) was estimated from the thermal expansion data. The results obtained from the above measurements are discussed, as is the microstructural evolution caused by the superplastic deformations. It was found that the specific heat was almost independent of microstructural evolution, whereas the thermal diffusivity, thermal conductivity and thermal expansion were quite sensitive to deformation-induced cavities. The changes in the average grain size and grain aspect ratio had almost no effect on the thermophysical properties within the present experimental range. (author)

  7. Mechanical properties of reinforced concrete exposed to salt injury condition. Flexural capacities and deformation properties of reinforced concrete beams

    International Nuclear Information System (INIS)

    It is described that the estimation method of mechanical performance of reinforced concrete deteriorated by salt injury will be established. In the study, the influence of reinforcement corrosion on flexural capacities and deformational properties were investigated through the results of indoor tests and exposure tests at the sea sides. Followings are the main conclusions obtained from the study. 1. The relationship between reinforcement corrosion and flexural capacities, deformational properties obtained by the indoor tests are almost the same as those by the exposure tests. 2. Corrosion of tensile reinforcement causes deterioration of bond performance between steel and concrete and changes crack patterns. 3. Deformational properties of reinforced concrete with the corrosion volume of under 100 mg/cm2 are hardly different from those without corrosion. 4. Flexural capacities of reinforced concrete decreased with the increase of reinforcement corrosion. Using the JSCE (Japanese Society of Civil Engineers) method and taking account of loss of cross section of reinforcement due to corrosion, yield and ultimate strengths can be calculated. (author)

  8. The effect of aluminum alloying on strength properties and deformation mechanisms of the Hadfield steel single crystals

    Science.gov (United States)

    Astafurova, E. G.; Tukeev, M. S.; Chumlyakov, Yu. I.

    2007-10-01

    The role of aluminum alloying on strength properties and deformation mechanisms (slip, twinning) of single crystals of Hadfield steel under tensile loading at T = 300 K is demonstrated. It is found out that aluminum alloying suppresses twinning deformation in the single crystals and, during slip, results in a dislocation structure change from a uniform dislocation distribution to a planar dislocation structure.

  9. Fatigue properties of magnesium alloy AZ91 processed by severe plastic deformation.

    Science.gov (United States)

    Fintová, Stanislava; Kunz, Ludvík

    2015-02-01

    Fatigue properties of cast AZ91 magnesium alloy processed by severe plastic deformation were investigated and compared with the properties of the initial cast state. The severe plastic deformation was carried out by equal channel angular pressing (ECAP). The ECAP treatment resulted in a bimodal structure. The bimodality consists in a coexistence of fine grained areas with higher content of Mg17Al12 particles and areas exhibiting larger grains and lower density of Mg17Al12 particles. Improvement of the basic mechanical properties of AZ91 (yield stress, tensile strength and ductility) by ECAP was significant. Also the improvement of the fatigue life in the low-cycle fatigue region was substantial. However the improvement of the fatigue strength in the high-cycle fatigue region was found to be negligible. The endurance limit based on 10(7) cycles for the cast alloy was 80 MPa and for the alloy processed by ECAP 85 MPa. The cyclic plastic response in both states was qualitatively similar; initial softening was followed by a long cyclic hardening. Fatigue cracks in cast alloy initiate in cyclic slip bands which were formed in areas of solid solution. In the case of severe plastic deformed material with bimodal structure two substantially different mechanisms of crack initiation were observed. Crack initiation in slip bands was a preferred process in the areas with large grains whereas the grain boundaries cracking was a characteristic mechanism in the fine grained regions. PMID:25498295

  10. Crystallization of Ca+ ions in a linear rf octupole ion trap

    International Nuclear Information System (INIS)

    A laser-cooling experiment with Ca+ ions trapped in a linear rf octupole ion trap is presented. The phase transition of the laser-cooled Ca+ ions from the cloud to the crystal state is observed by an abrupt dip of the laser-induced fluorescence spectrum and indicates that mK temperatures are obtained. We have also performed molecular dynamics simulations under various conditions to confirm this property by deducing axially symmetric structures of Coulomb crystals and by evaluating the translational temperatures of the laser-cooled ions. The simulation results show that for small numbers of ions novel ring-shaped crystals are produced. As the number of ions is increased, cylindrical layers in the ring crystal are sequentially formed. For more than 100 ions, also hexagonal and spiral structures emerge in parts of the large-size ion crystal, which has a length on the order of millimeters for the present geometrical arrangement and voltages. An advantage of the linear rf octupole trap is its large almost-field-free region in the middle of the trap, where the micromotion amplitude is small for trapped ions. These results demonstrate that such a multipole trap has attractive features for quantum computing and ultracold ion-atom collision studies

  11. The effect of carbon concentration and plastic deformation on ultrasonic higher order elastic properties of steel

    Science.gov (United States)

    Heyman, J. S.; Allison, S. G.; Salama, K.

    1985-01-01

    The behavior of higher order elastic properties, which are much more sensitive to material state than are second order properties, has been studied for steel alloys AISI 1016, 1045, 1095, and 8620 by measuring the stress derivative of the acoustic natural velocity to determine the stress acoustic constants (SAC's). Results of these tests show a 20 percent linear variation of SAC's with carbon content as well as even larger variations with prestrain (plastic deformation). The use of higher order elastic characterization permits quantitative evaluation of solids and may prove useful in studies of fatigue and fracture.

  12. Conflicting results for the deformation properties of forsterite, Mg2SiO4

    International Nuclear Information System (INIS)

    Deformation properties of forsterite have been deduced simultaneously from X-ray diffraction data affected by extinction in Bonn-Pittsburgh (B), and in Groningen (G). For the G crystals, GI and GII, extinction is anisotropic and considerably larger than for crystal B. Measurements were made with Mo radiation for B, and with Mo and Ag radiation for GI and GII. As the Becker and Coppens extinction model is not exact, the deformation properties had to be filtered from the data with refinement models. The flexible B model [?'s and populations for single exponential functions (SEF's) refined for l=0-4] and the more rigid G model (SEF's populations refined for l=0-3 and ? for l=0; further ?'s and n's fixed at standard values) yield different results. Refinement of ? makes the majority of the SEF's notably diffuse, presumably due to correlation with incorrect extinction corrections. The order of the deformation potentials at the Mg(1) and Mg(2) sites is reversed for B and G. Maxima on the Si-O bonds, which are polarized towards O, are smaller for G (0.20-0.25 e A-3) than for B (0.25-0.45 e A-3). Although each of the two sets of deformation properties looks acceptable by itself, the present comparison shows that neither of them may be sufficiently close to the truth. The diffraction data are available on request from the Electron Density Data Bank (Professor H. Burzlaff, Institut fuer Angewandte Physik, Bismarckstrasse 10, D-8520 Erlangen, Federal Retrasse 10, D-8520 Erlangen, Federal Republic of Germany). Details of the measurements are described in the paper. (orig.)

  13. Transport properties of water and glycol in an ultra high performance fiber reinforced concrete (UHPFRC) under high tensile deformation

    OpenAIRE

    Charron, Jean-philippe; Denarie?, Emmanuel; Bru?hwiler, Eugen

    2008-01-01

    Ultra High Performance Fiber Reinforced Concretes (UHPFRC) present outstanding mechanical properties and a very low permeability. Those characteristics make them very attractive for the rehabilitation of existing structures and the conception of new structures. To define the range of admissible tensile deformation in those materials, the influence of imposed tensile deformation and subsequent cracking on permeability and absorption was studied. The transport properties of water and glycol wer...

  14. Influences of surface effects and large deformation on the resonant properties of ultrathin silicon nanocantilevers

    International Nuclear Information System (INIS)

    The purpose of the present work is to quantify the influences of the discrete nature, the surface effects, and the large deformation on the bending resonant properties of long and ultrathin silicon nanocantilevers. We accomplish this by using an analytical semi-continuum Keating model within the framework of nonlinear, finite deformation kinematics. The semi-continuum model shows that the elastic behaviors of the silicon nanocantilevers are size-dependent and surface-dependent, which agrees well with the molecular dynamics results. It also indicates that the dominant effect on the fundamental resonant frequency shift of the silicon nanocantilever is adsorption-induced surface stress, followed by the discrete nature and surface reconstruction, whereas surface relaxation has the least effect. In particular, it is found that a large deformation tends to increase the nonlinear fundamental frequency of the silicon nanocantilever, depending not only on its size but also on the surface effects. Finally, the resonant frequency shifts due to the adsorption-induced surface stress predicted by the current model are quantitatively compared with those obtained from the experimental measurement and the other existing approach. It is noticed that the length-to-thickness ratio is the key parameter that correlates the deviations in the resonant frequencies predicted from the current model and the empirical formula. (condensed matter: structural, mechanical, and thermal properties)

  15. A new class of $f$-deformed charge coherent states and their nonclassical properties

    CERN Document Server

    Mortazavi, M

    2012-01-01

    Two-mode charge (pair) coherent states has been introduced previously by using $<\\eta|$ representation. In the present paper we reobtain these states by a rather different method. Then, using the nonlinear coherent states approach and based on a simple manner by which the representation of two-mode charge coherent states is introduced, we generalize the bosonic creation and annihilation operators to the $f$-deformed ladder operators and construct a new class of $f$-deformed charge coherent states. Unlike the (linear) pair coherent states, our presented structure has the potentiality to generate a large class of pair coherent states with various nonclassicality signs and physical properties which are of interest. Along this purpose, we use a few well-known nonlinearity functions associated with particular quantum systems as some physical appearances of our presented formalism. After introducing the explicit form of the above correlated states in two-mode Fock-space, several nonclassicality features of the c...

  16. Self-consistent description of static properties of nuclear deformation from nucleon-nucleon effective interactions

    International Nuclear Information System (INIS)

    A self-consistent description of deformed nuclei is presented in the Hartree-Fock approximation after correcting in an approximate but variational way for pairing correlations. Density dependent phenomenological effective interactions have been used, mainly according to the Skyrme's parametrization. Methods in use and various related approximations are reviewed in an extensive way. Calculated nuclei belong to the s-d shell, to the rare earth region, to the two transitional regions before and after the latter region, and to the actinide region. For all these nuclei, calculated deformation properties agree remarkably well with experimental data. Such results are extensively compared with those obtained in the more phenomenological approach due to Strutinsky. Finally the hypotheses formulated by Strutinsky are checked numerically in a systematic way, thus leading to the conclusion of the validity of the Strutinsky method

  17. Influence of cold deformation on structure and mechanical properties of alloys type 1430 sheets

    International Nuclear Information System (INIS)

    The influence of preliminary cold deformation on grain growth during quenching and mechanical properties of the alloys 1430 (Al-2.7%Mg-1.7%Li-1.6%Cu-0.1%Zr) sheets in different structural states was investigated. It was shown that the alloy 1430 with recrystallized structure has a low tendency to grain growth on secondary recrystallization. Critical reduction in area of 4% results in a growth of recrystallized grains during quenching from 25 up to 60 ?m. High relative elongation that is typical for the alloy sheets with recrystallized structure defines high stamping ability of as-delivered alloy as well as the possibility of its deformation with high reductions in artificially aged state. 3 figs., 1 tab

  18. Influence of materials properties on stress and deformation states of a prestressed concrete vessel

    International Nuclear Information System (INIS)

    The influence of changes in some material parameters on relevant operational states is studied for a vessel with a concrete liner temperature of 700C. The results are given for the following material properties: thermal conductivity, thermal expansion coefficient, young's modulus, temperature dependency of the creep, steel tendon relaxation. The influence of changes in the initial strain due to deformation of the vessel also gets a mention. As the behaviour at 700C does not deviate significantly from the behaviour described in the extensive studies on a vessel of 500C, the calculations in this paper are essentially confined to two final operational states which illustrate the influence of the material parameters on the strains and deformations which are of interest for the layout of the vessel. (orig./AK)

  19. Decay pathways and rotational properties of strongly deformed bands in ^168Hf

    Science.gov (United States)

    Ma, W. C.; Yadav, R. B.; Amro, H.; Varmette, P. G.; Zhang, Y. C.; Hagemann, G. B.; Herskind, B.; Schmidt, K. A.; Sletten, G.; Carpenter, M.; Janssens, R. V. F.; Khoo, T. L.; Lauritsen, T.; Lister, C. J.; Bracco, A.; Frattini, S.; Million, B.; Domscheit, J.; Hubel, H.; Hartley, D. J.; Riedinger, L. L.; Odegard, S. W.; Siem, S.

    2008-04-01

    Three strongly deformed bands were observed previously in ^168 Hf [1] and proposed as candidates of triaxial strongly deformed (TSD) bands. However, none of the bands was linked to known levels. Without the knowledge of level spins, parities, and excitation energies, it was difficult to gain a clear understanding of these bands. We have performed an extensive spectroscopic analysis for the ?-ray coincidence data obtained from a Gammasphere experiment at ANL. The decay pathways of TSD2 band to low-spin structures have been established, and the approximate spin values of levels in TSD1 band obtained. A detailed comparison of experimental properties of these bands and theoretical calculations, as well as the intrinsic configurations of the bands will be discussed. Work supported by U.S. DOE grant DE-FG02-95ER40939. [1] H. Amro et al., Physics Letters B 506 (2001) 39-44.

  20. Coriolis mixing of the octupole vibrational bands in 156Gd

    International Nuclear Information System (INIS)

    Coriolis mixing of negative parity states in 156Gd nucleus is considered within the framework of a phenomenological model. Energy spectrum and ratios of effective probabilities of E1-transitions from the levels of octupole bands are described. Possibilities of E1-transitions from K?=2--band states are discussed; intraband E2-transitions in K?=0--, 1-- and 2--bands are calculated. 16 refs., 2 figs., 4 tabs

  1. Unified description of quadrupole-octupole collective states in nuclei

    International Nuclear Information System (INIS)

    We present a unified description of quadrupole-octupole collective states in even-even nuclei in terms of an s-p-d-f boson model. This model enables us, for the first time, to describe K=0+ and K=0- bands within a single scheme covering vibrational to rotational situations. The moment of inertia varying within a band and the energy displacement are reproduced well. As examples, Ra and Th isotopes are analyzed. (orig.)

  2. Octupole excitations at high spins in A ? 160 nuclei

    International Nuclear Information System (INIS)

    The yrast and yrare states of 162Yb are studied within the cranked Nilsson model and random phase approximation. Special attention is paid to the analysis of experimental crossing points between different bands that form the yrast band. We found that, at the rotational frequency ?? > 0.3 MeV, there is onset of strong octupole correlations. The results of calculations demonstrate good agreement with available experimental data

  3. Ion cyclotron-resonance heating in a toroidal octupole

    International Nuclear Information System (INIS)

    rf power near the ion cyclotron-resonance frequency has been used to produce a hundredfold increase (from approximately-less-than1 to approx.100 eV) in the ion temperature in a toroidal octupole device. The heating produces no noticeable instabilities or other deleterious effects except for a high reflux of neutrals from the walls. The heating rate is consistent with theory and the limiting ion temperature is determined by charge-exchange losses

  4. Ion cyclotron resonance heating in a toroidal octupole

    International Nuclear Information System (INIS)

    A 1 MW, 2 msec pulse of rf power at the ion cyclotron frequency (2.6 MHz) was used to heat the ions from less than 1 eV to approximately 350 eV in a toroidal octupole device. The ion temperature is limited by charge exchange loss and agrees quantitatively with theoretical predictions. No parametric decay waves, enhanced diffusion, or other deleterious effects except for a high neutral reflux are observed to accompany the heating

  5. Investigation on microstructure, texture, and magnetic properties of hot deformed Nd-Fe-B ring magnets

    Science.gov (United States)

    Li, A. H.; Li, W.; Lai, B.; Wang, H. J.; Zhu, M. G.; Pan, W.

    2010-05-01

    Radially oriented Nd-Fe-B ring magnets have been prepared by backward extrusion of melt-spun powder. The position dependent of the microstructure, the magnetic properties, and the crystal alignment of the extruded rings have been investigated. The magnetic properties in radial direction increase slightly along the axis from the bottom to the middle then steeply decrease at the upper end of the ring. The magnetic properties and x-ray diffraction patterns of the upper end are very close to that of the isotropic pressed precursor. It suggests that the extruded ring approximately retains the initial structure at its upper end which is because the formation of texture is difficult at the initial stage of hot extrusion. Characteristic microstructure morphologies were found at different spatial positions: flake-shaped grains for the inner, elongated grains for the middle, and particle-shaped grains for the outer region in the cross section. Only particle-shaped grains were observed at the upper end of the ring. But the circumferential homogeneity of the surface magnetic flux densities is better in an extruded ring magnet than in a radially oriented ring prepared by sintering method. The deformation and texture formation processes were discussed. The deformation and texture formation in backward extruded magnets from melt-spun Nd-Fe-B precursors may possibly involve grain boundary sliding and grain rotation, solution-precipitation process, and preferred growth of Nd2Fe14B nanograins along the easy growth a-axis.

  6. Deformation properties of highly plastic fissured Palaeogene clay - Lack of stress memory?

    DEFF Research Database (Denmark)

    KrogsbØll, Anette; Hededal, Ole

    2012-01-01

    The geological preconsolidation of the Palaeogene clays in Denmark is estimated to 5-8 MPa or more, whereas laboratory and field experiences indicate values between 100 and 3000 kPa. Presumably, the high plasticity clay loses its memory of earlier preloads due to swelling, or as an effect of fissuring or debonding. Based on a large amount of high quality tests on Palaeogene clay partly encountered at Fehmarn Belt the typical deformational behaviour during unloading and swelling is discussed and evaluated with focus on stress states. K0-OCR relations are established and the relations are evaluated based on the degree of debonding caused by natural processes insitu as compared to processes induced during severe loading and unloading in laboratory. A long term oedometer test on Lillebælt Clay with a series of loading and unloading cycles was carried out. The test results are used to evaluate deformation properties, and to help explain the large primary and secondary swelling indices measured in Palaeogene claysand how they are related to preconsolidation stress. It is proven that the Palaeogene clay tends to “forget” the preconsolidation stress and the consequence is that OCR is not always a suitable parameter to estimate deformation and strength parameters from, unless additional information on structure of the clay is included. This is not solved yet.

  7. Property optimization of nanostructured ARB-processed Al by post-process deformation

    DEFF Research Database (Denmark)

    Huang, Xiaoxu; Kamikawa, Naoya

    2008-01-01

    The effect of post-process deformation on the mechanical properties of nanostructured aluminum (99.2% purity) has been investigated by cold rolling of samples which have been processed by accumulative roll bonding (ARB) to a strain of epsilon(vM) = 4.8. Samples have been cold rolled to 10, 15, and 50% reductions and ultimate tensile strength (UTS), yield stress and elongation have been determined by tensile testing at room temperature. The mechanical testing shows that cold rolling to low strains (10% and 15%) leads to softening and increase in elongation compared to the as-processed ARB material. In contrary, cold rolling to large strain (50%) results in significant strengthening. This leads to the suggestion of a transition strain within the range of 25-35% reduction by rolling. The microstructural evolution during post-process deformation has been followed by transmission electron microscopy showing a significant change in the dislocation structure when the strain is increased. Based on the experimental observations the mechanical behavior is related to the structural changes focusing on the characteristics of the dislocation structure present between the narrowly spaced lamellar boundaries in the deformed structure.

  8. Effect of cryogenic deformation on the structure and properties of chromium-nickel steels

    Science.gov (United States)

    Glezer, A. M.; Rusanenko, V. V.; Zhukov, O. P.; Libman, M. A.; Klippenshtein, A. D.

    2012-10-01

    The effect of rolling at a temperature of 77 K and subsequent tempering on the structure and properties of chromium-nickel 05Kh14N14T2 and 15Kh14N14Yu1 steels is investigated. The formation of a nanocrystalline martensite phase in an austenitic matrix has been established. It is shown that additional hardening of the metal occurs due to the precipitation of intermetallic phases during heat treatment. The steels under study are high-strength and hard-magnetic after cryogenic deformation and heat treatment.

  9. Processing of ultrafine-grained materials using severe plastic deformation: potential for achieving exception properties

    International Nuclear Information System (INIS)

    The processing of polycrystalline metals through the application of severe plastic deformation is attracting much attention because of the potential for achieving significant grain refinement to the submicrometer or nanometer level. This paper reviews the principles of this type of processing with emphasis on two different techniques: Equal-Channel Angular Pressing and High-Pressure Torsion. Exceptional properties may be achieved from these processes including high strength at ambient temperatures and a rapid superplastic forming capability at elevated temperatures. Some examples are presented demonstrating the potential use of this type of processing. (Author) 53 refs

  10. Effect of deformation and annealing on the microstructure and magnetic properties of grain-oriented electrical steels

    International Nuclear Information System (INIS)

    The effect of plastic deformation and subsequent annealing on the magnetic properties and microstructure of a grain-oriented (GO) electrical steel has been studied. True strain (?) from 0.002 to 0.23 was applied by rolling in two directions, rolling (RD) and transverse (TD). The deterioration of power losses varies according to the direction of deformation. Annealing the strained material-at 800 deg. C/2 h-leads to a recrystallization and restored magnetic properties. The main components of annealed-textures are around 15-35o from those of deformed-textures for both RD and TD. Rolling along {1 1 0} direction leads to the development of deformation twins

  11. Effect of deformation and annealing on the microstructure and magnetic properties of grain-oriented electrical steels

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Nicolau A. [IPT - Instituto de Pesquisas Tecnologicas, Av. Prof. Almeida Prado, 532, Sao Paulo, SP 05508-901 (Brazil)]. E-mail: nicolau@ipt.br; Campos, Marcos F. de [Inmetro - DIMCI/DIMAT - Av. Nossa Senhora das Gracas 50, Xerem, Duque de Caxias, RJ 25250-020 (Brazil)]. E-mail: mfcampos@inmetro.gov.br; Landgraf, Fernando J.G. [IPT - Instituto de Pesquisas Tecnologicas, Av. Prof. Almeida Prado, 532, Sao Paulo, SP 05508-901 (Brazil)]. E-mail: f.landgraf@usp.br

    2006-09-15

    The effect of plastic deformation and subsequent annealing on the magnetic properties and microstructure of a grain-oriented (GO) electrical steel has been studied. True strain ({epsilon}) from 0.002 to 0.23 was applied by rolling in two directions, rolling (RD) and transverse (TD). The deterioration of power losses varies according to the direction of deformation. Annealing the strained material-at 800 deg. C/2 h-leads to a recrystallization and restored magnetic properties. The main components of annealed-textures are around 15-35{sup o} from those of deformed-textures for both RD and TD. Rolling along {l_brace}1 1 0{r_brace} <0 0 1> direction leads to the development of deformation twins.

  12. Effect of deformation and annealing on the microstructure and magnetic properties of grain-oriented electrical steels

    Science.gov (United States)

    Castro, Nicolau A.; de Campos, Marcos F.; Landgraf, Fernando J. G.

    2006-09-01

    The effect of plastic deformation and subsequent annealing on the magnetic properties and microstructure of a grain-oriented (GO) electrical steel has been studied. True strain (?) from 0.002 to 0.23 was applied by rolling in two directions, rolling (RD) and transverse (TD). The deterioration of power losses varies according to the direction of deformation. Annealing the strained material—at 800 °C/2 h—leads to a recrystallization and restored magnetic properties. The main components of annealed-textures are around 15-35° from those of deformed-textures for both RD and TD. Rolling along {1 1 0} direction leads to the development of deformation twins.

  13. Microstructure and some properties of FeCr25Co15 alloy subjected to plastic deformation by complex load

    Energy Technology Data Exchange (ETDEWEB)

    Korneva, A.; Bieda, M.; Sztwiertnia, K. [Polish Academy of Science, Inst. of Metallurgy and Materials Science, Krakow (Poland); Korznikowa, G.; Korznikov, A. [Russian Academy of Sciences, Inst. of Problems of Metal Superplasticity, Ufa (Russian Federation)

    2008-09-15

    The microstructural, mechanical and magnetic properties of FeCr25Co15 alloy were examined after upset followed by torsion. Deformation was carried out at temperatures that corresponded to the appearance of {alpha} + {gamma} phases. During the process, the initial lamellar microstructure of the material was transformed into a globular one. In the sample sections parallel to the upsetting direction a gradient microstructure, with a layer of submicron grains in the highest deformation zone, was formed. The thickness of the zone did not significantly depend on the deformation temperature. Measurements of the mechanical properties after magnetic treatment showed that the plasticity and strength of the deformed samples increased in comparison with the high coercive state. (orig.)

  14. Effect of aging and plastic deformation upon the mechanical and thermal properties of cobalt-containing invar alloys

    International Nuclear Information System (INIS)

    Mechanical, magnetic and thermal properties of quenched (1150 deg C, water) alloys N36K10T3, N36K10Kh5T2, N36K5T2 are investigated after age hardening (650 deg C) and high temperature deformation (1100-800 deg C) with subsequent ageing. It is shown that supersaturated solid solution decomposition in invar alloys studied results in an increase of strength properties and coercive force but decreases ductility and saturation magnetization. Plastic deformation of invars is revealed to enhance ultimate strength, yield strength and coercive force. Additional ageing of deformed materials increases strength properties and decreases plastic ones. Saturation magnetization correlates best with mechanical properties compared to other magnetic parameters

  15. Humidity and multiscale structure govern mechanical properties and deformation modes in films of native cellulose nanofibrils.

    Science.gov (United States)

    Benítez, Alejandro J; Torres-Rendon, Jose; Poutanen, Mikko; Walther, Andreas

    2013-12-01

    Nanopapers formed by stiff and strong native cellulose nanofibrils are emerging as mechanically robust and sustainable materials to replace high-performance plastics or as flexible, transparent and "green" substrates for organic electronics. The mechanical properties endowed by nanofibrils crucially depend on mastering structure formation processes and on understanding interfibrillar interactions as well as deformation mechanisms in bulk. Herein, we show how different dispersion states of cellulose nanofibrils, that is, unlike tendencies to interfibrillar aggregation, and different relative humidities influence the mechanical properties of nanopapers. The materials undergo a humidity-induced transition from a predominantly linear elastic behavior in dry state to films displaying plastic deformation due to disengagement of the hydrogen-bonded network and lower nanofibrillar friction at high humidity. A concurrent loss of stiffness and tensile strength of 1 order of magnitude is observed, while maximum elongation stays near constant. Scanning electron microscopy imaging in plastic failure demonstrates pull-out of individual nanofibrils and bundles of nanofibrils, as well as larger mesoscopic layers, stemming from structures organized on different length scales. Moreover, multiple yielding phenomena and substantially increased elongation in strongly disengaged networks, swollen in water, show that strain at break in such nanofibril-based materials is coupled to relaxation of structural entities, such as cooperative entanglements and aggregates, which depend on the pathway of material preparation. The results demonstrate the importance of controlling the state of dispersion and aggregation of nanofibrils by mediating their interactions, and highlight the complexity associated with understanding hierarchically structured nanofibrillar networks under deformation. PMID:24245557

  16. Effects of pre-deformation on the martensitic transformation and magnetocaloric property in Ni-Mn-Co-Sn ribbons

    International Nuclear Information System (INIS)

    This paper investigates the martensitic transformation and magnetocaloric effect in pre-deformed Ni-Mn-Co-Sn ribbons. The experimental results show that the reverse martensitic transformation temperature TM increases with the increasing pre-pressure, suggesting that pre-deformation is another effective way to adjust TM in ferromagnetic shape memory alloys. Large magnetic entropy changes and refrigerant capacities are obtained in these ribbons as well. It also discusses the origin of the enhanced martensitic transformation temperature and magnetocaloric property in pre-deformed Ni-Mn-Co-Sn ribbons

  17. Deformed photon-added nonlinear coherent states and their non-classical properties

    International Nuclear Information System (INIS)

    In this paper, we will try to present a general formalism for the construction of deformed photon-added nonlinear coherent states (DPANCSs) |?, f, m), which in a special case lead to the well-known photon-added coherent state (PACS) |?, m). Some algebraic structures of the introduced DPANCSs are studied and particularly the resolution of the identity, as the most important property of generalized coherent states, is investigated. Meanwhile, it will be demonstrated that the introduced states can also be classified in the f-deformed coherent states, with a special nonlinearity function. Next, we will show that these states can be produced through a simple theoretical scheme. A discussion on the DPANCSs with negative values of m, i.e. |?, f, -m), is then presented. Our approach has the potentiality to be used for the construction of a variety of new classes of DPANCSs, corresponding to any nonlinear oscillator with known nonlinearity function, as well as arbitrary solvable quantum system with known discrete, non-degenerate spectrum. Finally, after applying the formalism to a particular physical system known as the Poeschl-Teller (P-T) potential and the nonlinear coherent states corresponding to a specific nonlinearity function f(n)=?n, some of the non-classical properties, such as the Mandel parameter, second-order correlation function, in addition to first- and second-order squeezing of the corresponding states, will be investigated numerically.ated numerically.

  18. Microstructure and properties of ceramics and composites joined by plastic deformation

    International Nuclear Information System (INIS)

    A review is presented of the design of suitable materials systems for joining by high-temperature plastic deformation, details of the joining techniques, microstructures and properties of the resulting composite bodies, and prospects and limitation for this type of joining technology. Joining parameters and resulting forms are discussed for Al2O3/mullite particulate composites, Y2O3-stabilized ZrO2 particulate/Al2O3 particulate and whisker-reinforced composites, hydroxyapatite bioceramics, La0.85Sr0.15MnO3 electronic ceramics, MgF2 optical ceramics, and Ni3Al intermetallics. Results are contrasted with those obtained by other methods of joining brittle, high-temperature materials, with special focus on durability and mechanical properties

  19. On the relationship between forearc deformation, frictional properties and megathrust earthquakes

    Science.gov (United States)

    Cubas, Nadaya; Singh, Satish

    2014-05-01

    A better understanding of the relation between the structural geology and the morphology of forearc wedges with frictional properties could provide insights on earthquake mechanics. Therefore, we study, with simple mechanical analysis allowing for inverse studies, the three subduction zones that produced the major earthquakes of the 21st century : Central Chile (Maule 2010 Mw 8.8), NE Japan (Tohoku-Oki 2011 Mw 9.0) and Sumatra (Sumatra-Andaman 2004 Mw 9.1, Nias 2005 Mw 8.7). We first apply the critical taper theory that yields the effective friction of the subduction interface, the wedge internal friction and pore fluid pressure. We then apply the limit analysis approach to constrain variations of frictional properties along the megathrust from the location and style of forearc faulting. We show that seismic ruptures most often coincide with the mechanically stable part of the wedge whereas regions undergoing aseismic slip are at critical state, consistent with evidence for active deformation. In the rupture area, we found a low effective dynamic friction, probably reflecting strong dynamic weakening. Where no frontal rupture was observed, we obtain intermediate values of long-term effective friction along the frontal aseismic zone, implying hydrostatic pore pressure. On the contrary, where the rupture reached the seafloor (Tohoku-Oki earthquake, parts of the Sumatra-Andaman 2004 earthquake), a very low long-term effective friction and a high pore pressure are observed. The difference of properties of the frontal wedge might reflect differences in permeability. A lower permeability would enhance dynamic weakening and allow for frontal propagation of ruptures. We also show that spatial variations of frictional properties between aseismic and seismogenic zones can lead to the activation of splay faults. We also show that a high pore pressure along accretionary wedges can change the vergence of frontal thrusts. As a consequence, wedge morphology and deformation can be used to improve seismic and tsunamigenic risk assessment.

  20. The influence of strain rate, deformation temperature and stacking fault energy on the mechanical properties of Cu alloys

    International Nuclear Information System (INIS)

    Cu–Ge alloys with different stacking fault energies (SFEs) were prepared by induction melting and processed by severe plastic deformation (SPD) using three different deformation techniques, including rolling at room temperature (RTR), rolling at the liquid nitrogen temperature (LNR), and Split Hopkinson Pressure Bar (SHPB) impact followed by room temperature rolling (HK+RTR). The effects of SFE, strain rate and deformation temperature on the microstructures and mechanical properties were systematically investigated by X-ray diffraction analyses and tensile tests. It was found that the dislocation density and twin density of all the Cu alloys after the SPD processing increased with decreasing SFE, increasing strain rate or reducing deformation temperature, which led to simultaneously enhanced strength and improved ductility due to effective grain refinement. The mechanical properties of the Cu alloys can be optimized to a combination of high strength and excellent ductility by lowering the SFE, the intrinsic property of metals, or manipulating the extrinsic deformation conditions, that is, increasing strain rate, and/or decreasing deformation temperature

  1. Nuclear deformation study from fast neutron scattering

    International Nuclear Information System (INIS)

    Studies of elastic and inelastic scattering of fast neutrons from vibrational and rotational nuclei lead to determination of the quadrupole, hexadecapole and octupole deformation parameters of the target nuclei. The success of the analyses, which are based on phenomenological models, proves that precise information about the shape of nuclei can be obtained. These informations are compared to those deduced from other reactions mechanisms such as Coulomb excitation with protons, ?-particles or heavy ions

  2. A study on the mechanical properties and deformation behavior of injection molded PMMA-TSP laminated composite

    Science.gov (United States)

    Wang, Jaeyoon; Lee, Moon Kyu; Park, Seon-Mi; Hong, Seokmoo; Kim, Naksoo

    2012-03-01

    To evaluate the deformed features of a polymer and touch screen panel laminated material and to secure a reliability of the design method, it is crucial to predict a thermo-mechanical behavior of the polymers. The reliability problems of polymer-TSP laminated module subjected to temperature and humidity changes mainly occur due to features with time-dependent material properties as well as differences in the coefficients of thermal expansion between the polymer and TSP. Therefore, it is necessary to consider the viscous behavior which causes changes in material properties which include temperature-dependent properties along with the time-dependent properties. In this study, a tensile test is conducted to obtain fundamental material properties and a creep test is used to characterize viscous properties of the polymer. Material properties from the tensile and the creep test are verified by the tensile and creep simulations. Also, the finite element analysis is used to simulate the time-dependent behaviors during a high temperature conditions while predicting thermal deformations. Numerical results are compared with experimental results. The result shows that the shape deformations of the polymer-TSP laminated module calculated by the finite element analysis with visco-elastic-plastic material model are in a good agreement with the experiment. Based on analytical results, we predict the thermal deformation of the PMMA-TSP composite plate in consideration of the effect of viscous features and set up the organized numerical analysis procedure using FE analysis.

  3. Octupole Ordering Model for the Phase IV of CexLa1-xB6

    CERN Document Server

    Kubo, K; Kubo, Katsunori; Kuramoto, Yoshio

    2003-01-01

    An octupole ordering model is studied by the mean field theory, and its relevance to the phase IV of CexLa1-xB6 is discussed. The observed lattice distortion along the [111] direction is interpreted in terms of the \\Gamma_{5g}-type ferro-quadrupole moment induced by an antiferro-octupole ordered state with \\Gamma_{5u} symmetry. The octupole model also accounts for the cusp in the magnetization as in the N\\'{e}el transition, and the softening of the elastic constant C_{44} below the ordering temperature. However, the internal magnetic field due to the octupole moment is smaller than the observed one by an order of magnitude. Also discussed is the possibility of a pressure induced antiferromagnetic moment in the octupole-ordered state.

  4. Design of transport lines for uniforming beam distribution with octupoles

    Science.gov (United States)

    Guo, Y. Y.; Xu, G.

    2013-02-01

    The intensity distribution of a typical particle beam is an approximate Gaussian distribution while many applications require the beam to be uniform. Local bright spots on the targets for high-power Gaussian beams create difficult cooling problems and shorten the lifetime of the target. In this paper, we have theoretically studied uniformization of the transverse beam profile using two octupole magnets placed at particular locations in the beam transport line. The details about the requirements on magnet strength and phase advance will be shown. As an example, we take a set of China Spallation Neutron Source parameters to simulate the beam. The simulation result agrees well with theoretical formulas.

  5. Observation of highly enhanced E3-transitions in sup(198,200)Po. Evidence for octupole instability at Z>=84 and N<=114

    International Nuclear Information System (INIS)

    sup(198,200)Po have been studied by in beam ?-spectroscopy with the sup(182,184)W(20Ne,4n) reaction at 105 to 112 MeV. Both nuclei exhibit 8+, 11-, and 12+ isomers for which lifetimes and g-factors have been measured, that determine their single particle structure. The a priori highly hindered (?hsub(9/2)isub(13/2)11-->?h2sub(9/2)8+) E3-transition becomes with 25 Weisskopf units very strong in 198Po suggesting that octupole vibrations or deformations are important in this region of nuclei. (orig.)

  6. Improvement of mechanical properties in severely plastically deformed Ni–Cr alloy

    International Nuclear Information System (INIS)

    Highlights: ? The application of cross-roll rolling to the Ni–20Cr alloy effectively enhanced grain refinement. ? This grain refinement in cross-roll rolling directly improved the mechanical properties. ? Particularly, yield strength increased to 800% relative to those of the initial material. ? We discussed the increase in mechanical properties in terms of the grain refinement and texture development. -- Abstract: This study was carried out to evaluate the grain refining and mechanical properties in alloys that undergo severe plastic deformation (SPD). Conventional rolling (CR) and cross-roll rolling (CRR) were introduced as methods for SPD, and a Ni–20Cr alloy was selected as the experimental material. The materials were cold rolled to 90% thickness reduction and subsequently annealed at 700 °C for 30 min to obtain the fully recrystallized microstructure. The annealed materials after cold rolling were assessed through electron backscattered diffraction (EBSD) analysis to investigate the grain boundary characteristic distributions (GBCDs). The CRR process was more effective than the CR process in developing grain refinement; the grain size decreased from 70 ?m in the initial material to 4.2 ?m (CR) and 2.4 ?m (CRR), respectively. The grain refinement affected mechanical properties such as microhardness, yield, and tensile strength, which were significantly increased relative to the initial material.

  7. Effects of dehydration on the viscoelastic properties of vocal folds in large deformations.

    Science.gov (United States)

    Miri, Amir K; Barthelat, François; Mongeau, Luc

    2012-11-01

    Dehydration may alter vocal fold viscoelastic properties, thereby hampering phonation. The effects of water loss induced by an osmotic pressure potential on vocal fold tissue viscoelastic properties were investigated. Porcine vocal folds were dehydrated by immersion in a hypertonic solution, and quasi-static and low-frequency dynamic traction tests were performed for elongations of up to 50%. Digital image correlation was used to determine local strains from surface deformations. The elastic modulus and the loss factor were then determined for normal and dehydrated tissues. An eight-chain hyperelastic model was used to describe the observed nonlinear stress-stretch behavior. Contrary to the expectations, the mass history indicated that the tissue absorbed water during cyclic extension when submerged in a hypertonic solution. During loading history, the elastic modulus was increased for dehydrated tissues as a function of strain. The response of dehydrated tissues was much less affected when the load was released. This observation suggests that hydration should be considered in micromechanical models of the vocal folds. The internal hysteresis, which is often linked to phonation effort, increased significantly with water loss. The effects of dehydration on the viscoelastic properties of vocal fold tissue were quantified in a systematic way. A better understanding of the role of hydration on the mechanical properties of vocal fold tissue may help to establish objective dehydration and phonotrauma criteria. PMID:22483778

  8. The relationships among brittleness, deformation behavior, and transport properties in mudstones: An example from the Horonobe Underground Research Laboratory, Japan

    Science.gov (United States)

    Ishii, Eiichi; Sanada, Hiroyuki; Funaki, Hironori; Sugita, Yutaka; Kurikami, Hiroshi

    2011-09-01

    Mudstones are low-permeability sedimentary rocks; however, when shear stresses induced by tectonic movement or nonhydrostatic stresses exceed the shear strength of the rock, brittle or ductile deformation occurs. The nature of this deformation is controlled by the brittleness of the mudstone. If brittle deformation occurs, the resulting dilatant structures may increase the permeability and change the transport properties of the strata. This paper addresses the relationships among brittleness, deformation behavior, and transport properties in mudstones at the Horonobe Underground Research Laboratory, Japan. Geological, mechanical, and hydrogeological data from borehole investigations and laboratory tests were systematically interpreted using a brittleness index (BRI), which is the ratio of the unconfined compressive strength to the effective vertical stress. For mudstones under natural strain rates and low temperatures, ductile deformation occurs when BRI BRI is 2-8, and brittle deformation occurs when BRI >8, although semibrittle behavior may also occur at the brittle-ductile boundary. When BRI >8 and faulting is well developed, the mudstone behaves hydrogeologically as a fractured medium at the mesoscopic scale, whereas for BRI BRI concept is a useful tool for systematically characterizing the hydromechanical behavior of mudstones; for example, when assessing the effectiveness of mudstone as a long-term barrier in disposal repositories for radioactive waste.

  9. FlexyDos3D: a deformable anthropomorphic 3D radiation dosimeter: radiation properties

    Science.gov (United States)

    De Deene, Y.; Skyt, P. S.; Hil, R.; Booth, J. T.

    2015-02-01

    Three dimensional radiation dosimetry has received growing interest with the implementation of highly conformal radiotherapy treatments. The radiotherapy community faces new challenges with the commissioning of image guided and image gated radiotherapy treatments (IGRT) and deformable image registration software. A new three dimensional anthropomorphically shaped flexible dosimeter, further called ‘FlexyDos3D’, has been constructed and a new fast optical scanning method has been implemented that enables scanning of irregular shaped dosimeters. The FlexyDos3D phantom can be actuated and deformed during the actual treatment. FlexyDos3D offers the additional advantage that it is easy to fabricate, is non-toxic and can be molded in an arbitrary shape with high geometrical precision. The dosimeter formulation has been optimized in terms of dose sensitivity. The influence of the casting material and oxygen concentration has also been investigated. The radiophysical properties of this new dosimeter are discussed including stability, spatial integrity, temperature dependence of the dosimeter during radiation, readout and storage, dose rate dependence and tissue equivalence. The first authors Y De Deene and P S Skyt made an equivalent contribution to the experimental work presented in this paper.

  10. Statistical investigation of position-specific deformation pattern of nucleosome DNA based on multiple conformational properties.

    Science.gov (United States)

    Yang, Xi; Yan, Yan

    2011-01-01

    The histone octamer induced bending of DNA into the super-helix structure in nucleosome core particle, is very unique and vital for DNA packing into chromatin. We collected 48 nucleosome crystal structures from PDB and applied a multivariate analysis on the nucleosome structural data. Based on the anisotropic nature of DNA structure, a principal conformational subspace (PCS) is derived from multiple properties to represent the most significant variances of nucleosome DNA structures. The coupling of base pair-oriented parameters with sugar phosphate backbone parameters presented in principal dimensionalities reveals two main deformation modes that have supplemented the existing physical model. By using sequence alignment-based statistics, a positiondependent conformational map for the super-helical DNA path is established. The result shows that the crystal structures of nucleosome DNA have much consistency in position-specific structural variations and certain periodicity is found to exist in these variations. Thus, the positions with obvious deformation patterns along the DNA path in nucleosome core particle are relatively conservative from the perspective of statistics. PMID:22125381

  11. Strength and deformational properties of concrete at elevated temperatures up to 5000C

    International Nuclear Information System (INIS)

    Mechanical property tests of concrete at elevated temperatures had been performed. The experimental results obtained by the strength tests, were shown at each strength test. Compressive strength: sigmacu(T)/sigmacu, room = 1.00(normal temp. 0C), sigmacu(T)/sigmacu, room = -0.00195T + 1.544(280 0C -6T2 + 4.813 x 10-5T + 1.0(normal temp. 0C); Modulus of Rupture: sigmabu(T)/sigmabu, room = -0.0021T + 1.402(100 0C 0C); Young's Modulus: Esub(c)(T)/Esub(c), room = -0.00124T + 0.802(100 0C 0C); Relationship between Decrease rates of Young's Modulus(W) and Weight of Test Specimen(G): W = 0.047G + 2.88(100 0C 0C); compressive Strain at the Maximum Stress: R strain = 0.00263T + 0.932(normal temp. 0C), which means the ratio of the compressive strain at maximum stress at high temperature to that at normal temperature. It was made clear by the past researches that the thermal expansion coefficients of deformed bars increase according to temperature rise. The experimental results obtained by the free expansion tests using D16 deformed bars in Civil Engineering Laboratory supported the general tendency described above. Further, the strengths as well as Young's modulus of concrete at es well as Young's modulus of concrete at elevated temperatures were discussed. (Kubozono, M.)

  12. Non-yrast spectra of odd-A nuclei in a model of coherent quadrupole-octupole motion

    CERN Document Server

    Minkov, N; Drumev, K; Strecker, M; Lenske, H; Scheid, W

    2013-01-01

    The model of coherent quadrupole and octupole motion (CQOM) is applied to describe non-yrast split parity-doublet spectra in odd-mass nuclei. The yrast levels are described as low-energy rotation-vibration modes coupled to the ground single-particle (s.p.) state, while the non-yrast parity-doublet structures are obtained as higher-energy rotation-vibration modes coupled to excited s.p. states. It is shown that the extended model scheme describes both the yrast and non-yrast quasi parity-doublet spectra and the related B(E1) and B(E2) transition rates in different regions of heavy odd-A nuclei. The involvement of the reflection-asymmetric deformed shell model to describe the single-particle motion and the Coriolis interaction on a deeper level is discussed.

  13. Deformation mechanisms, length scales and optimizing the mechanical properties of nanotwinned metals

    International Nuclear Information System (INIS)

    Refinement of microstructural length scales and modification of interface character offer opportunities for optimizing material properties. While strength and ductility are commonly inversely related, nanotwinned polycrystalline copper has been shown to possess simultaneous ultrahigh strength and ductility. Interestingly, a maximum strength is found at a small, finite twin spacing. We study the plastic deformation of nanotwinned polycrystalline copper through large-scale molecular dynamics simulations. The simulations show that plastic deformation is initiated by partial dislocation nucleation at grain boundary triple junctions. Both pure screw and 60o dislocations cutting across twin boundaries and dislocation-induced twin boundary migration are observed in the simulation. Following twin boundary cutting, 60o dislocations frequently cross-slip onto {0 0 1} planes in twin grains and form Lomer dislocations. We further examine the effect of twin spacing on this Lomer dislocation mechanism through a series of specifically designed nanotwinned copper samples over a wide range of twin spacings. The simulations show that a transition in the deformation mechanism occurs at a small, critical twin spacing. While at large twin spacings, cross-slip and dissociation of the Lomer dislocations create dislocation locks that restrict and block dislocation motion and thus enhance strength, at twin spacings below the critical size, cross-slip does not occur, stepical size, cross-slip does not occur, steps on the twin boundaries form and deformation is much more planar. These twin steps can migrate and serve as dislocation nucleation sites, thus softening the material. Based on these mechanistic observations, a simple, analytical model for the critical twin spacing is proposed and the predicted critical twin spacing is shown to be in excellent agreement both with respect to the atomistic simulations and experimental observations. In addition, atomistic reaction pathway calculations show that the activation volume of this dislocation crossing twin boundary process is consistent with experimental values. This suggests that the dislocation mechanism transition reported here for the first time can be a source of the observed transition in nanotwinned copper strength.

  14. Microstructure and Properties of Deformation Processed Polycrystalline Ni47Ti44Nb9 Shape Memory Alloy

    Science.gov (United States)

    Yin, XiangQian; Mi, Xujun; Li, Yanfeng; Gao, Baodong

    2012-12-01

    The objective of this work was to investigate the relationships between process and microstructure and property in polycrystalline Ni47Ti44Nb9 alloy. Three processes: (1) hot-forged, (2) cold-drawn, and (3) cold-rolled were investigated. The microstructure was tested by means of optical microscope, x-ray diffraction, and electron backscatter diffraction, and then crystalline orientation distribution functions and inverse pole figures were measured. The results indicated that hot-forging eliminated dendritic microstructure and fined the eutectic structure. It also induced a fiber texture, which paralleled to the axial direction. The cold drawing and cold-rolling had a further effect in grain refinement. And the cold-drawn specimens contained a strong fiber texture paralleling to the deformation direction, while the cold-rolled tubes formed crystalline directions paralleling the axial direction and crystalline directions of crystalline arranged along the circumferential direction. The notably distinctive recoverability of different processed materials was observed and discussed.

  15. Common creep deformation properties among casts of type 316 stainless steel at practical stresses

    International Nuclear Information System (INIS)

    Although nonlinear finite element analysis is now well established as a computational technique, the usefulness of its detailed numerical predictions is limited by the reliablility of the constitutive equations and hence upon the underlying material data. Creep deformation data are usually required for calculations at moderate stresses and long times for which it is impractical to test in detail for all casts employed in constructions. The alternatives are extrapolated data from accelerated tests or existing data for other casts. These possibilities are examined here in terms of the regularity of creep behaviour among casts at moderate stresses and for indivual casts at low and high stresses. It is suggested that the former regularity is greater and hence that inter-cast comparison with limited testing of the casts of interest may be the best course for determining creep properties for use in finite element analysis. (orig./GL)

  16. Electronic and transport properties of radially deformed double-walled carbon nanotube intramolecular junction

    Energy Technology Data Exchange (ETDEWEB)

    Yang Xiaoping [Group of Computational Condensed Matter Physics, National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China) and Department of Physics, Huainan Normal University, Huainan, Anhui 232001 (China)]. E-mail: bunnyxp@hotmail.com; Dong Jinming [Group of Computational Condensed Matter Physics, National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China)

    2004-09-20

    The electronic and transport property of a radially deformed double-walled carbon nanotube (DWNT) intramolecular junction (IMJ) has been studied by the tight-binding (TB) model combined with the first-principle calculations. The geometrical structures of the DWNT IMJ have been first optimized in energy by the universal force field (UFF) method. It is found that when heavily squashed, the DWNT will become an insulator-coated metallic wire, and the conductance near the Fermi level has been significantly changed by the radial squash. Specially, several resonance conductance peaks appear at some energies in the conduction band of the squashed DWNT IMJ. Finally, we have also investigated the conductance variation due to change of the length of the central semiconductor in the squashed DWNT IMJ. Furthermore, a promising pure carbon nanoscale electronic device is proposed based on the DWNT IMJ.

  17. Tensile properties of a nickel-base alloy subjected to surface severe plastic deformation

    International Nuclear Information System (INIS)

    A surface severe plastic deformation (S2PD) method has been applied to bulk specimens of HASTELLOY C-2000 alloy, a nickel-base alloy. The mechanical properties of the processed C-2000 alloy were determined via tensile tests and Vickers hardness measurements, whereas the microstructure was characterized using scanning electron microscopy, transmission electron microscopy, and X-ray diffractometry. The improved tensile strength was related to the nanostructure at the surface region, the residual compressive stresses, and the work-hardened surface layer, all of which resulted from the S2PD process. To understand the contributions of these three factors, finite element modeling was performed. It was found that the improved tensile strength could be interpreted based on the contributions of nano-grains, residual stresses, and work hardening

  18. Rare-earth nuclei: Radii, isotope-shifts and deformation properties in the relativistic mean field theory

    International Nuclear Information System (INIS)

    A systematic study of the ground-state properties of even-even rare earth nuclei has been performed in the framework of the Relativistic Mean-Field (RMF) theory using the parameter set NL-Sh. Nuclear radii, isotope shifts and deformation properties of the heavier rare-earth nuclei have been obtained, which encompass atomic numbers ranging from Z=60 to Z=70 and include a large range of isospin. It is shown that RMF theory is able to provide a good and comprehensive description of the empirical binding energies of the isotopic chains. At the same time the quadrupole deformations ?2 obtained in the RMF theory are found to be in good agreement with the available empirical values. The theory predicts a shape transition from prolate to oblate for nuclei at neutron number N=78 in all the chains. A further addition of neutrons up to the magic number 82 brings about the spherical shape. For nuclei above N-82, the RMF theory predicts the well-known onset of prolate deformation at about N-88, which saturates at about N-102. The deformation properties display an identical behaviour for all the nuclear chains. A good description of the above deformation transitions in the RMF theory in all the isotopic chains leads to a successful reproduction of the anomalous behaviour of the empirical isotopic shifts of the rare-earth nuclei. The RMF theory exhibits a remarkable success in providing a unified and microscopic description of various empirical data. (orig.)

  19. Superdeformed nuclei: Shells-vs-liquid drop, pairing-vs-thermal excitations, triaxial-vs-octupole shapes, super-superdeformation

    Energy Technology Data Exchange (ETDEWEB)

    Dudek, J.

    1987-01-01

    Mechanisms influencing the behavior of superdeformed nuclei are studied using several well established nuclear structure techniques. In particular: pairing, thermal excitation, shell and liquid-drop mechanisms are considered. The effects of quadrupole and hexadecapole (both axial and non-axial), and octupole deformation degrees of freedom are studied. Most of the results are illustrated using the case of /sup 152/Dy nucleus in which a superdeformed band extending up to I approx. 60 h-bar has been found in experiment. Some comparisons between /sup 152/Dy and the nuclei in the neighborhood are given. Calculations show that pairing ''de-aligns'' typically 6 to 8 units of angular momentum, as compared to the corresponding rigid rotation. This takes place for spins extending up to the highest limit, and thus diminishes the effective moments of inertia. Predicted octupole shape susceptibility is extremely large, significantly stronger than the susceptibilities known in the ground-states of many Actinide nuclei. Consequences of this result for the near-constancy of the dynamical moments of inertia are pointed out. Nuclear level densities calculated in function of spin, excitation energy and deformation explain the ''unusual'' side feeding pattern of the /sup 152/Dy superdeformed states. Predictions of super-superdeformed nuclear states (axis ratio varying between 2:1 and 3:1 or more) are given and exemplified for Erbium nuclei. Finally, the problem of superdeformation stability and the influence of increased collective inertia on a barrier penetration are examined. An analytical expression for the effective inertia parameter is obtained and its derivation outlined. 35 refs., 9 figs.

  20. Effects of Membrane Material Properties on the Deformation of Elastic Capsules in a Shear Flow

    Science.gov (United States)

    Chan, Kit Yan; Eggleton, Charles

    2006-03-01

    The deformation process of elastic capsules in a simple shear flow is studied numerically using the immersed boundary method to probe the influence of membrane material properties. Membrane models that are representative of linear elastic membrane (Hookean law), strain hardening membrane (Skalak), and strain softening membrane (Mooney-Rivlin, neo-Hookean) and the Evans-Skalak model developed from thermodynamic principles to represent the behavior of a lipid bilayer and a cytoskeletal network, are used to study the effects of membrane material properties on the response of the capsule at various shear rates. Simulation results indicate that both the time to reach steady state and the final steady shape of the capsule are sensitive to the choice of the membrane model and parameter values used. These experimentally measurable quantities may be compared with computations for determining suitable model of a particular capsule of interest, and the associated material properties. Local strain and energy distributions computed also provide additional information that is not easily accessible experimentally.

  1. Octupole Excitation of Trapped Ion Motion for Precision Mass Measurements

    Science.gov (United States)

    Bollen, G.; Ringle, R.; Schury, P.; Schwarz, S.; Sun, T.

    2005-04-01

    National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI, USA An azimuthal octupole radiofrequency field has been used to excite the ion motion of ^40Ar^+ ions stored in a Penning trap. A resonant response was observed at twice the ions' true cyclotron frequency ?c=q/m.B. The experiment has been performed with the 9.4-T Penning trap system of the recently commissioned LEBIT facility at the NSCL at MSU [1]. Similar to the excitation with an azimuthal quadrupole field at ?c [2,3], octupole excitation at 2?c gives rise to a periodic beating of the ion motion between magnetron and reduced cyclotron motion. Differences are observed in the dependence of the excited ion motion on initial amplitudes and phases of the radial eigen motions. The observed behavior of the ions is found to be in good agreement with the results of numerical simulations. The technique still requires further testing but the first results indicate that 2?c excitation may provide benefits that are similar to doubling the magnetic field strength B. In particular precision mass measurements of short-lived rare isotopes may benefit from this technique by being able to reach a given precision with shorter ion storage and observation times. [1] S. Schwarz et al, Nucl. Instr. Meth. B204 (2004) 507 [2] G. Bollen et al., J. Appl. Phys. 68 (1990) 4355 [3] M. König et al., Int. J. Mass Spec. Ion. Proc. 142 (1995) 95

  2. Postseismic Deformations of the Aceh, Nias and Benkulu Earthquakes and the Viscoelastic Properties of the Mantle

    Science.gov (United States)

    Fleitout, L.; Garaud, J.; Cailletaud, G.; Vigny, C.; Simons, W. J.; Ambrosius, B. A.; Trisirisatayawong, I.; Satirapod, C.; Geotecdi Song

    2011-12-01

    The giant seism of Aceh (december 2004),followed by the Nias and Bengkulu earthquakes, broke a large portion of the boundary between the Indian ocean and the Sunda block. For the first time in history, the deformations associated with a very large earthquake can be followed by GPS, in particular by the SEAMERGE (far-field) and SUGAR (near-field) GPS networks. A 3D finite element code (Zebulon-Zset) is used to model both the cosismic and the postseismic deformations. The modeled zone is a large portion of spherical shell around Sumatra extanding over more than 60 degrees in latitude and longitude and from the Earth's surface to the core-mantle boundary. The mesh is refined close to the subduction zone. First, the inverted cosismic displacements on the subduction plane are inverted for and provide a very good fit to the GPS data for the three seisms. The observed postseismic displacements, non-dimensionalized by the cosismic displacements, present three very different patterns as function of time: For GPS stations in the far-field, the total horizontal post-seismic displacement after 4 years is as large as the cosismic displacement. The velocities vary slowly over 4 years. A large subsidence affects Thailand and Malaysia. In the near-field, the postseismic displacement reaches only some 15% of the cosismic displacement and it levels off after 2 years. In the middle-field (south-west coast of Sumatra), the postseismic displacement also levels-off with time but more slowly and it reaches more than 30% of the cosismic displacement after four years. In order to fit these three distinct displacement patterns, we need to invoke both viscoelastic deformation in the asthenosphere and a low-viscosity wedge: Neither the vertical subsidence nor the amplitude of the far-field horizontal velocities could be explained by postseismic sliding on the subduction interface. The low viscosity wedge permits to explain the large middle-field velocities. The viscoelastic properties of the asthenosphere are consistent with a Burger rheology with a transient creep represented by a Kelvin-Voigt element with a viscosity of 3.1018Pas and ? Kelvin}=? {elastic/3. A second Kelvin-Voigt element with very limited amplitude may explain some characteristics of the short time-scale signal. The viscosity of the low viscosity wedge is also of the order of 3. 1018 Pas. The near-field displacements are not explained by viscoelastic relaxation and post-seismic slip on the fault plane (15% of the cosismic slip) occured in the months after the earthquakes. These large post-seismic deformations affect the deviatoric stresses in the whole Sunda-block. They also imply sizable far-field interseismic deformations.

  3. Feasibility study for compensating the anharmonicities in LEP with additional octupoles

    CERN Document Server

    Brüning, Oliver Sim

    1997-01-01

    Operating LEP with the 108/90 optics at the end of the 1996 run indicated a limitation of the dynamic aperture due to a combined effect of non-linear resonances and anharmonicities. This note analyses the feasibility of improving the dynamic aperture in LEP by compensating the anharmonicities with additional octupoles. The presented scheme reduces the anharmonicities in LEP by more than 60%, resulting in a sufficiently large dynamic aperture. The scheme places octupoles in all odd IP's with 4 octupoles powered in two pairs per IP.

  4. Comparative studies of constitutive properties of nanocrystalline and bulk iron during compressive deformation

    International Nuclear Information System (INIS)

    Highlights: ? Yield strength of nano-Fe (2.0 GPa) is 15 times higher than that of micron-Fe (0.13 GPa). ? Compressive deformation does not build up additional dislocations in nano-Fe. ? Pressure induced dislocation annihilation in micron-Fe during compression. ? Dislocation annihilation is a dominant mechanism for plastic energy dissipation. - Abstract: We present a comparative study of the mechanical properties of body-centered cubic nanocrystalline iron (nano-Fe) and microcrystalline iron (micro-Fe) by in situ high-pressure synchrotron X-ray diffraction under triaxial compression. For nano-Fe with a starting high dislocation density of 1016 m-2, the peak broadening is almost reversible upon unloading from 8.6 GPa to atmospheric pressure, indicating that no additional dislocations are built up during compressive deformation inside grains, at grain boundaries or twin boundaries. Furthermore, an orientation-dependent surface strain is found to be stored in the surface layer of the bcc nano-Fe, which is in agreement with the core-shell model of the nanocrystals. For micro-Fe, a significant and continuous peak sharpening and the associated work softening were observed after the sample is yielded at pressures above 2.0 GPa, which can be presumably attributed to a pressure-induced dislocation annihilation. This finding/interpretation supports the hypothesis that the annihilation of dislocations is one of the dominant mechanisms underlying the ominant mechanisms underlying the plastic energy dissipation. The determined yield strength of 2.0 GPa for nano-Fe is more than 15 times higher than that for micro-Fe (0.13 GPa), indicating that the nanoscale grain-size reduction is a substantially more effective strengthening mechanism than conventional carbon infusion in iron.

  5. Phase stability, deformation mechanisms, and mechanical properties of Nb-Al-Ti alloys

    International Nuclear Information System (INIS)

    The phase stability, deformation mechanisms and mechanical properties of two alloys based on Nb3Al containing additions of Ti have been studied. These two alloys, with nominal compositions (in at.%) of Nb-15Al-10Ti (alloy 1) and Nb-15Al-40Ti (alloy 2), have the B2 crystal structure in as cast form. The ALCHEMI technique has been employed to assess qualitatively the distribution of atom types over the two sublattices of the B2 compounds. It is found that Ti and Al occupy different sublattices in alloy 2. Heat-treatment of alloy 1 at 1,100 C results in the precipitation of an A15 phase in the B2 matrix. Annealing at 900 C for short time introduces an w-phase. Prolonged annealing of alloy 1 at 700 C reveals the presence of an orthorhombic phase. The same orthorhombic phase is also found to exist between 800 and 1,000 C in alloy 2. Specific orientation relationships exist between the matrix phase and precipitates. The yield strength in compression of Alloy 1 and 2 were determined at various temperatures. Alloy 1 is strong compared to superalloy IN 718 over a range of temperatures up to 950 C. Both alloys with the B2 crystal structure are deformed by one or more of the following slip systems, namely (110), (112) and (123). Dislocations with Burgers vector, b, given by b= are present in the form of dissociated superpartial pairs, each with b=1/2. The inherent ductility of both alloys is indicated by the active slip systems and illustratedby the active slip systems and illustrated by 20% elongation to failure obtained in alloy 2 under room temperature tensile test. A trend of increasing tensile yield stress with increasing antiphase domain size was found. No evidence of interaction between dislocations and antiphase boundaries has been found to account for this increase of strength

  6. Mechanical properties and constitutive relations for tantalum and tantalum alloys under high-rate deformation

    International Nuclear Information System (INIS)

    Tantalum and its alloys have received increased interest as a model bcc metal and for defense-related applications. The stress-strain behavior of several tantalums, possessing varied compositions and manufacturing histories, and tantalum alloyed with tungsten, was investigated as a function of temperature from -196 C to 1,000 C, and strain rate from 10-3 s-1 to 8,000 s-1. The yield stress for all the Ta-materials was found to be sensitive to the test temperature, the impurity and solute contents; however, the strain hardening remained very similar for various ''pure'' tantalums but increased with alloying. Powder-metallurgy (P/M) tantalum with various levels of oxygen content produced via different processing paths was also investigated. Similar mechanical properties compared to conventionally processed tantalums were achieved in the P/M Ta. This data suggests that the frequently observed inhomogeneities in the mechanical behavior of tantalum inherited from conventional processes can be overcome. Constitutive relations based upon the Johnson-Cook, the Zerilli-Armstrong, and the Mechanical Threshold Stress models were evaluated for all the Ta-based materials. Parameters were also fit for these models to a tantalum-bar material. Flow stresses of a Ta bar stock subjected to a large-strain deformation of var-epsilon = 1.85 via multiple upset forging were obtained. The capabilities and limitations of each model for large-strain applications are examined. The deformation mechanisms controlling high-rate plasticity in tantalum are revisited

  7. Plasma resistivity measurements in the Wisconsin levitated octupole

    International Nuclear Information System (INIS)

    Resistivity measurements parallel to the magnetic field were made on gun injected plasmas ranging in density from 109cm-3 to 101parallelcm-3 in the Wisconsin levitated octupole with toroidal and poloidal magnetic fields. The 109cm-3 plasma was collisionless with lambda/sub mfp/ > 100 mirror lengths, had T/sub e/ = 10 eV, T/sub i/ = 30 eV and was found to have anomalous resistivity scaling like eta = ?T/sub e//n/sub e/ when E/sub parallel/ > E/su c/ is the Dreicer critical field. The 1012cm-3 plasma was collisional with lambda/sub mfp/ < mirror length, had T/sub e/ = T/sub i/ approx. = .2 eV and was found to have Spitzer resistivity when E/sub parallel/ < E/sub c/

  8. Off-beam ?-ray spectroscopy of octupole states in ^152Gd

    Science.gov (United States)

    Babilon, M.; Zamfir, N. V.; McCutchan, E. A.; Kusnezov, D.; Ai, H.; Amro, H.; Beausang, C. W.; Casten, R. F.; Heinz, A.; Hughes, R. O.; Meyer, D. A.; Plettner, C.; Ressler, J. J.; Bayer, W.; Galaviz, D.

    2004-10-01

    The rare earth region with Z ˜ 56 or 64 and N ˜ 88 was predicted to present strong octupole correlations. In order to obtain experimental information on low-spin octupole states in ^152_64Gd_88, they were populated via EC/?^+ decay and studied via off-beam coincidence ?-ray spectroscopy at the Yale Moving Tape Collector. The character of the octupole excitations in the Z ˜ 64 and N ˜ 88 region was studied using the Interacting Boson Approximation (IBA) model, by incorporating p and f bosons in the usual IBA-sd model. The model shows that the octupole correlations increase with spin and at a medium spin (J ˜ 10), they become very strong in agreement with a phenomenological analysis. This work was supported by the U.S. DOE Grant No. DE-F602-91-ER-40609.

  9. Two-phonon-octupole excitation in 208Pb

    International Nuclear Information System (INIS)

    In the framework of the present thesis quasi-elastic processes in the reactions 206 Pb+208 Pb and 208 Pb+208 Pb were studied at an incident energy slightly above the Coulomb barrier (6.2 MeV/u) were studed. By means of the measured Particle-gamma correlations the quasi-elastic collisions were separated from the deep inelastic ones. Determined were the absolute cross sections and angular distributions of the exitation by inelastic collisions as well as by one- and two-neutron transfer. For the states excited by inelatic scattering the multiplicities of the ? quanta emitted in their decay were experimentally determined. The measured angular distributions of the inelastic reactions were compared with CCBA calculations. As most important result of this thesis the experimental detection of a member of the 2-phonon-octupole multiplet is to be considered. A hitherto unknown ? transition in the spectrum of -2-0-8 Pb with an energy of 2.485 MeV was detected. Because of the measured ?? coincidence ratios in 208 Pb this transition was assigned to the level scheme of 208Pb. Its decay to the 1-phonon state 3- pursues via an E1-transition to the 5- -state and a following E2-transition. The angular distribution of the 2-phonon-octupole state was calculated in the framework of the CCBA and compared with the experiment. The comparison with the CCBA calculation indicates a spin of I?=6+ or 4+ . The experimental angular distributions of the one-neutron transfer reactions to 207 Pb and 209 Pb were compared with DWBA calculations. (orig./HSI)

  10. Effect of preliminary plastic deformation on structure and properties of boride phases

    International Nuclear Information System (INIS)

    Studied have been the structure peculiarities of the diffusion layers, produced during the boronizing in the process of the electric heating of the steels, previously cold-plastic deformed. Armco iron, St20 steel samples have been used for the research through the electronic-microscopy and radioactive isotopes techniques. It is established that the preliminary cold deformation accelerates the boronizing process under the rapid electric heating conditions. The preliminary deformation is responsible for the appearance of the boronized layers, characterized with a higher defectiveness when compared with layers produced on the non-deformed samples of the researched steel grades

  11. Analysis of f-p model for octupole ordering in NpO2

    CERN Document Server

    Kubo, K; Kubo, Katsunori; Hotta, Takashi

    2005-01-01

    In order to examine the origin of octupole ordering in NpO2, we propose a microscopic model constituted of neptunium 5f and oxygen 2p orbitals. To study multipole ordering, we derive effective multipole interactions from the f-p model by using the fourth-order perturbation theory in terms of p-f hopping integrals. Analyzing the effective model numerically, we find a tendency toward \\Gamma_{5u} antiferro-octupole ordering.

  12. Evaluation of the Mechanical Properties of AA 6063 Processed by Severe Plastic Deformation

    Science.gov (United States)

    Jafarlou, Davoud Mashhadi; Zalnezhad, Erfan; Hamouda, Abdelmagid Salem; Faraji, Ghader; Mardi, Noor Azizi Bin; Hassan Mohamed, Mohsen Abdelnaeim

    2015-02-01

    In this study, the mechanical properties, including surface hardness, tensile strength, fatigue, and fretting fatigue behavior of AA 6063 processed by equal channel angular pressing as the most efficient severe shear plastic deformation (SPD) technique, were investigated. Following the SPD process, samples were subjected to heat treatment (HT), hard anodizing (HA), and a combination of HT and HA. Rotating-bending fretting fatigue tests were performed to explore the samples' response to the fretting condition. From the experimental fatigue and fretting fatigue tests, it was apparent that the SPD treatment had a positive effect on enhancing the fatigue and fretting fatigue lives of the samples at low and high-cyclic loads compared with the HT technique by 78 and 67 pct, and 131 and 154 pct respectively. The results also indicate that the SPD + HT technique significantly increased the fatigue and fretting fatigue lives of the samples at high and low cycles by 15.56 and 8.33 pct, and 14.4 and 5.1 pct respectively, compared with the SPD method. HA of AA6063 increased the fatigue and fretting fatigue lives of SPD + HT-processed samples at low cycle by 15.5 and 18.4 pct respectively; however, at high cycle, HA had reverse effects, whereby the fatigue and fretting fatigue lives of SPD + HT-processed samples decreased by 16.7 and 30 pct, respectively.

  13. Microstructural evolution and mechanical properties of high strength magneisum alloys fabricated by deformation processing

    Science.gov (United States)

    Mansoor, Bilal

    The goal of this research was to develop high strength Mg by thermo-mechanical processing. Several novel techniques were developed to impart large plastic strains on Mg alloys and Mg based composites. The main emphasis of this work was on investigating the effect of different processing schemes on grain-refinement and texture modification of processed material. The room-temperature and elevated-temperature mechanical behavior of processed-Mg was studied in detail. Biaxial corrugated pressing, also known as alternate biaxial reverse corrugation processing was applied to twin-roll cast AZ31 Mg and warm-extruded ZK60 Mg. Friction stir processing to partial depths was applied to thixomolded AM60 Mg and warm-extruded ZK60 Mg. A new process called "bending reverse-bending", was developed and applied to hot rolled AZ31-H24 Mg. A Mg/Al laminated composite was developed by hot pressing and rolling. In processed condition, Mg alloys exhibit enhancement in room-temperature strength and ductility, as well as elevated temperature formability. It was concluded that improvement in mechanical properties of processed-Mg is strongly influenced by grain size and precipitates; while ductility largely depends on resulting deformation textures.

  14. The effects of severe plastic deformation on some properties relevant to Ti implants

    Scientific Electronic Library Online (English)

    Anibal Andrade, Mendes Filho; Vitor Luiz, Sordi; Maurizio, Ferrante.

    2012-02-01

    Full Text Available In some types of surgical implants, such as bone screws and plates, Grade 2 Ti is seriously considered as a replacement for the Ti-6Al-4V alloy. Advantages are lower cost and the absence of Al and V, which have been identified as potentially harmful to human health. The present paper shows that the [...] lower strength of the commercially pure metal can be enhanced by Severe Plastic Deformation followed by conventional cold rolling, so as to reach a strength level higher than the technical requirements applicable to the alloy. This was ascertained by tensile and Vickers hardness tests from which it was concluded that the best combination of properties are obtained by submitting the metal to Equal Channel Angular Pressing (four passes at 300 °C) followed by a 70% thickness reduction by cold rolling. Although the present results are valid for the material only, and not for the product considered, that is, bone screws, it appears that this solution is a step towards the replacement of the Ti6-4 alloy by Grade 2 Ti, at least for some types of metallic medical implants.

  15. Studying physical properties of deformed intact and fractured rocks by micro-scale hydro-mechanical-seismicity model

    Science.gov (United States)

    Raziperchikolaee, Samin

    The pore pressure variation in an underground formation during hydraulic stimulation of low permeability formations or CO2 sequestration into saline aquifers can induce microseismicity due to fracture generation or pre-existing fracture activation. While the analysis of microseismic data mainly focuses on mapping the location of fractures, the seismic waves generated by the microseismic events also contain information for understanding of fracture mechanisms based on microseismic source analysis. We developed a micro-scale geomechanics, fluid-flow and seismic model that can predict transport and seismic source behavior during rock failure. This model features the incorporation of microseismic source analysis in fractured and intact rock transport properties during possible rock damage and failure. The modeling method considers comprehensive grains and cements interaction through a bonded-particle-model. As a result of grain deformation and microcrack development in the rock sample, forces and displacements in the grains involved in the bond breakage are measured to determine seismic moment tensor. In addition, geometric description of the complex pore structure is regenerated to predict fluid flow behavior of fractured samples. Numerical experiments are conducted for different intact and fractured digital rock samples, representing various mechanical behaviors of rocks and fracture surface properties, to consider their roles on seismic and transport properties of rocks during deformation. Studying rock deformation in detail provides an opportunity to understand the relationship between source mechanism of microseismic events and transport properties of damaged rocks to have a better characterizing of fluid flow behavior in subsurface formations.

  16. Microstructure, mechanical properties, deformation, and fracture of V-4Ti-4Cr alloys

    International Nuclear Information System (INIS)

    Full text of publication follows: The effect of the mode of thermomechanical treatment (TMT) on the microstructure, mechanical properties, mechanisms of plastic deformation, and fracture of V-4Ti-4Cr alloys has been studied. For these alloys, the TMT modes that provide a volumetrically uniform distribution of superfine particles of oxy-carbonitride phases, a substantial growth of their density, and an increase in recrystallization temperature have been substantiated. Interrelations have been found between the microstructure of the alloys and the features of their mechanical behavior, such as the level of strength and plasticity, discontinuous yielding, and an abnormal temperature dependence of strength. It has been shown that these phenomena are underlined by the high thermodynamic instability of the V-4Ti-4Cr alloys after TMT which is due to the presence of supersaturated solid solutions of titanium with interstitial elements, local inhomogeneities in composition, and superfine particles of oxy-carbonitride phases. The great variety of thermally activated obstacles that appear during TMT and mechanical tests at elevated temperatures are responsible for the significantly extended range of the anomalous temperature dependence of yield strength and the conservation of high values of strength up to T ?850 deg. C. The phenomenon of strain localization has been revealed whose temperature range coincides with the range of discontinuous yielding. The conclusion has been maous yielding. The conclusion has been made that this phenomenon can be a direct reason for the discontinuous yielding that testifies to local mechanical instabilities in strain localization bands. Analysis of possible mechanisms and important features of the structural and stream instabilities of plastic flow in these bands has been performed. The TMT modes have been substantiated that provide high thermal stability of the microstructure and a significant increase in short-time strength of the V-4Ti-4Cr alloys over a wide temperature range (from 20 to 1000 deg. C), leaving rather much margin for plasticity. (authors)

  17. Effect of severe plastic deformation on the properties of the Fe-36 % Ni invar alloy

    International Nuclear Information System (INIS)

    Temperature dependences of saturation magnetization and thermal expansion coefficient are investigated for alloy Fe-36 % Ni in various structural states obtained by severe plastic deformation by torsion under quasi-hydrostatic pressure with subsequent annealing at temperatures of 125, 225, 280, 350 and 500 deg C. A decrease of thermal expansion coefficient of the invar alloy in a temperature range of 20-100 deg C as well as formation of superstructured precipitates resulted from severe plastic deformation are revealed

  18. The influence of plastic deformation and heat treatment on microstructure and mechanical properties of W-Ni-Fe alloy

    International Nuclear Information System (INIS)

    The paper presents the results of microstructural observations, fractography and tensile tests investigations performed at room temperature on series of 90% W - 7% Ni - 3% Fe alloy specimens representative of 'as sintered state', cold worked (10-40%) and subjected to additional annealing (500-750 oC). Changes in the microstructure have been described quantitatively using a computer sided image analysis and qualitatively by scanning electron microscopy (fractography). Chemical composition changes in micro-areas were investigated by electron probe X-ray microanalysis. The results were correlated with mechanical properties of the alloy. After cold rolling the tungsten particles change their shape from nearly spherical into discs. On the fracture surface of 'as sintered' alloy after tensile test, fracture paths prevail along tungsten interfaces and tungsten-matrix separation. The fracture paths through the matrix have a ductile character. With the increasing plastic deformation, fraction of fracture paths across tungsten particles increases. For the samples subjected to 40% deformation tungsten cleavage is predominant. Simultaneously, ductility of the matrix markedly decreases. The deformation of tungsten particles as well as strain hardening of matrix increases the strength and hardness of WHA. The UTS of the alloy subjected to 40% deformation increases by approximately 42%. The annealing of alloy after cold working at the temperature range of 500-620 ooC increases the UTS to 1565 MPa without changing its elongation to fracture, which remains lower than that in 'as sintered state'. (author)

  19. High spin states and evidence for octupole correlations in 117Xe

    International Nuclear Information System (INIS)

    High-spin states of 117Xe were investigated by means of in-beam ?-ray spectroscopic techniques via the reaction of 28Si bombarding a 92Mo target at beam energies of 100-120 MeV. A positive-parity rotational band decaying into the yrast negative-parity band by a series of enhanced E1 transitions was observed for the first time, implying the existence of octupole correlations in 117Xe. The ?d5/2 band was firmly established up to 27/2+ and the B(M1)/B(E2) ratios were extracted from the relative intensities of ?-rays in this band. The previously known ?h11/2 and ?g7/2 [413]5/2+ ? = -1/2 bands were confirmed and extended up to high spins and two bandcrossings are observed in the latter at ?? = 0.33 and 0.44 MeV, respectively. The rotational properties of these bands are discussed by total routhian surface (TRS) and cranking shell model (CSM) calculations. From the ?-?-t measurement the 11/2- and 7/2- levels were identified as two isomers with half-lives of 59.4 ± 20 ns and 16.5 ± 8.0 ns, respectively. (author)

  20. Prior thermo-mechanical processing to modify structure and properties of severely deformed low carbon steel

    Science.gov (United States)

    Zrnik, J.; Lapovok, R.; Raab, G. I.

    2014-08-01

    The article focuses on the severe plastic deformation (SPD) of low carbon steel AISI 1010 performed at increased temperature. The grain refinement of ferrite structure is monitored and described with respect to different initial steel structure modified by thermal and thermomechanical (TM) treatment (TM) prior severe plastic deformation. The refinement of coarse initial ferrite structure with grain size in range of 30 - 50 gm resulted from solutioning was conducted then in two steps. Preliminary structure refinement has been achieved due to multistep open die forging process and quite uniform ferrite structure with grain size of the order of gm was obtained. The further grain refinement steel structure was then accomplished during warm Equal Channel Angular Pressing (ECAP phi = 120°) at 300°C, introducing different strain in range of ?ef = 2.6 -4. The change of microstructure in dependence of the effective strain was evaluated by SEM and TEM study of thin foils. The high straining of steel resulted in extensive deformation of ferrite grains and formation of mixture of submicron grains structure in banded deformed structure with dense dislocation network and subgrains. The dynamic polygonization process, due to increased ECAP temperature, modified the submicrocrystalline structure formation. There was only indistinctive difference observed in structure refinement when considering different initial structure of steel. The tensile behaviour was characterized by strength increase followed by softening. None work hardening phenomenon appeared at tensile deformation of deformed bars.

  1. Oxide dispersion strengthened ferritic alloys. 14/20% chromium: effects of processing on deformation texture, recrystallization and tensile properties

    International Nuclear Information System (INIS)

    The ferritic oxide dispersion strengthened alloys are promising candidates for high temperature application materials, in particular for long life core components of advanced nuclear reactors. The aim of this work is to control the microstructure, in order to optimise the mechanical properties. The two ferritic alloys examined here, MA956 and MA957, are obtained by Mechanical Alloying techniques. They are characterised by quite anisotropic microstructure and mechanical properties. We have investigated the influence of hot and cold working processes (hot extrusion, swaging and cold-drawing) and recrystallization heat treatments on deformation textures, microstructures and tensile properties. The aim was to control the size of the grains and their anisotropic shape, using recrystallization heat treatments. After consolidation and hot extrusion, as-received materials present a extremely fine microstructure with elongated grains and a very strong (110) deformation texture with single-crystal character. At that stage of processing, recrystallization temperature are very high (1450 degrees C for MA957 alloy and 1350 degrees C for MA956 alloy) and materials develop millimetric recrystallized grains. Additional hot extrusion induce a fibre texture. Cold-drawing maintains a fibre texture, but the intensity decreases with increasing cold-work level. For both materials, the decrease of texture intensities correspond to a decrease of the recrystallization temperatures (from 1350 degrees C for a low cold-work level to 750 degrees C for 60 % cold-deformation, case of MA956 alloy) and a refinement of the grain size (from a millimetric size to less than an hundred of micrometer). Swaging develop a cyclic component where the intensity increases with increasing deformation in this case, the recrystallization temperature remains always very high and the millimetric grain size is slightly modified, even though cold-work level increases. Technologically, cold-drawing is the only way that permits the decreasing of the recrystallization temperature of several hundred degrees and giving the best compromise between mechanical strength and ductility. (author). 72 refs., 6 appends

  2. The effect of post-deformation aging on superelastic properties of Ni50.9Ti thin wires attaining micro and nano-substructure

    International Nuclear Information System (INIS)

    Highlights: ? Precipitation of Ni4Ti3 during aging at 450 °C is hindered after severe cold work. ? Nanostructure formation improves the superelastic behavior of Ni-rich NiTi. ? Deformations less than 0.4 result in work hardening and reduce plateau strain. ? Deformations more than 0.4 yield in high stress and strain values of upper plateau. -- Abstract: Superelastic properties of Ni50.9Ti shape memory wires were studied after cold drawing and post-deformation annealing at 450 °C. Characteristic transformation temperatures were determined using differential scanning calorimetry. Microstructural investigations were performed using optical and transmission electron microscopy. Results indicate that deformations more than 0.4 of true strain yield in high stress and high strain values of upper plateau. On the other hand, deformations less than 0.4 result in work hardening and reduce plateau strain. Post-deformation heat treatment at 450 °C leads to precipitation of Ni4Ti3 particles and development of recovered microstructure in slightly cold drawn wires. Post-deformation annealing of wires with cold work value of 0.6 in true strain develop nanocrystalline microstructure and hindered the formation of Ni4Ti3 precipitates. Precipitation of Ni4Ti3 particles improves the superelastic properties of not cold drawn wires. However, in comparison with annealed and aged wires, severely deformed wires attain better superelastic properties after annealing at 450 °C without any Ni4Ti3 precipitates

  3. Interseismic deformation along the Mexican Subduction Zone: GPS-constrained coupling, and relationships with seismic and aseismic fault behavior, long term deformation and fault properties

    Science.gov (United States)

    Rousset, B.; Graham, S. E.; Cubas, N.; Radiguet, M.; Lasserre, C.; Socquet, A.; Campillo, M.; Walpersdorf, A.; Cotte, N.; DeMets, C.

    2013-12-01

    Recent observations have shown that a large diversity of mechanisms accommodates the deformation on subduction zones interfaces, especially with the discovery of slow slip events. Our study aims at comparing Oaxaca and Guerrero areas in the Mexican subduction zone. In these two areas, slow slip events have been discovered in the vicinity of seismic gaps, as well as tremor activity. We derive a regional, interseismic coupling map based on continuous GPS. It reveals lateral variations of coupling at shallow depth (0-25 km, offshore), with two well coupled zones (coupling > 0.7) alternating with two low coupled zones (coupling 0.7 as well), with a down dip, northern limit between coupled and uncoupled areas that is laterally homogeneous, at a distance of 170 km from the trench. Coupling spatial variations are first analyzed with respect to the spatial extension of Slow Slip Events, Tremors and Earthquakes. The analysis of the long-term morphology (bathymetry, topography, sedimentation, gravity) also highlights longitudinal variations, consistent in overall with the GPS-derived coupling variations. This suggests that these coupling variations are, to the first order, persistent over geological time scales (10^6 yr), and representative of fault plane properties that influence the building of the morphology. A mechanical analysis based on the critical tapper theory aims at reconciling geodetic observations and long term observations by determining lateral variations of frictional properties on critical areas of the subduction interface.

  4. Effect of cold deformation on latent energy value and high-temperature mechanical properties of 12Cr18Ni10Ti steel

    International Nuclear Information System (INIS)

    Energetic and magnetic characteristics and also the high-temperature mechanical properties depending on the preliminary cold deformation of 12Cr18Ni10Ti steel are presented. It is shown that the value of storage energy in the steel has being grown with increase of the deformation. The rate of its growth has been increased after beginning of martensitic ???'- transformation when value of comparative storage energy at first decreased and then has been stay practically constant. Level of mechanical properties of the steel at 1073 K has been determined not only by value of cold deformation but and structural reconstruction corresponding to deformations 35-45% and accompanying with ?'-phase martensite formation and change of energy accumulating rate. Preliminary cold deformation (40-60 %) does not improve high- temperature plasticity of steel samples implanted by helium. refs. 7, figs. 2

  5. Effect of multiaxial deformation Max-strain on the structure and properties of Ti-Ni alloy

    Science.gov (United States)

    Khmelevskaya, I. Yu; Kawalla, R.; Prokoshkin, S. D.; Komarov, V. S.

    2014-08-01

    The severe plastic deformation (SPD) forming ultrafine-grained (nanocrystalline or nanosubgrained) structure is one of the most effective ways to improve the functional properties of Ti-Ni-based shape memory alloys [1, 2]. In the present work, the SPD of near-equiatomic Ti-Ni alloy was carried out using the multi-axial deformation module Max-strain, which is a part of the physical simulation system "Gleeble 3500". The deformation was performed at a constant temperature of 400°C with speed of 0.5 mm/s in six passes without interpass pauses. The accumulated true strain was about 3. As a result, a mixed ultrafine-grained/subgrained structure with grain/subgrain sizes from 50 to 300 nm and a high density of free dislocations formed. The resulting structure is close to a nanoscale region and provides a significant advantage in the basic functional property - completely recoverable strain - as compared with a conventional recrystallized structure: 7% versus 2%.

  6. High power ICRH experiments on the Wisconsin levitated octupole

    International Nuclear Information System (INIS)

    Preliminary ICRH experiments have begun on the Wisconsin Levitated Octupole. In order to study heating, energy confinement, and high ? plasmas, a 1.8 to 3 MHz oscillator and antenna have been installed. The oscillator and antenna have been installed. The oscillator is capable of delivering 2 MW of RF power for 10 msec, and to date up to 0.5 MW has been coupled into the plasma. At a density of approx. 6 x 1012 cm-3, T/sub e/ reaches a maximum of 30 eV as measured by Langmuir probes and VUV spectroscopy. Charge exchange measurements of T/sub i/ show Maxwellian components at 95 and 190 eV, with an energy confinement time of approx. 1 msec. Electron energy confinement is limited by impurity radiation, and several methods of impurity control are being tested. Current experiments also include direct measurement of the RF electric field, antenna loading measurements, variation of the oscillator frequency, and ohmic heating of the electrons

  7. Detailed investigation of octupole vibrational states in {sup 168}Yb

    Energy Technology Data Exchange (ETDEWEB)

    Pascu, Sorin; Derya, Vera; Endres, Janis; Hennig, Andreas; Netterdon, Lars; Pickstone, Simon G.; Spieker, Mark; Zilges, Andreas [Institut fuer Kernphysik, Universitaet Koeln (Germany)

    2013-07-01

    The experimental evidence for the presence of octupole vibrational states in {sup 168}Yb is presented. In order to populate the excited states in this nucleus, the {sup 166}Er(?,2n?){sup 168}Yb fusion evaporation reaction was used with a beam energy of 24 MeV. Using the coincidence method, the level scheme was corrected and extended up to 3 MeV, both for the positive and negative parity states. In a second step, the lifetimes of five excited states were measured by using the fast timing method with the Bucharest HPGe and LaBr{sub 3}:Ce detector array using the triple-? coincidence method. Reduced E1 and E2 transition probabilities were extracted from the measured lifetimes and compared, when possible, with similar observables in neighboring isotopes, showing a smooth behavior with increasing mass. The positive and negative-parity states revealed by this experiment are compared with the Interacting Boson Model and are found to be in good agreement.

  8. Solvation of glucose, trehalose, and sucrose by the soft-sticky dipole-quadrupole-octupole water model

    Science.gov (United States)

    Te, Jerez A.; Tan, Ming-Liang; Ichiye, Toshiko

    2010-05-01

    Water structure around sugars modeled by partial charges is compared for soft-sticky dipole-quadrupole-octupole (SSDQO), a fast single-site multipole model, and commonly used multi-site models in Monte Carlo simulations. Radial distribution functions and coordination numbers of all the models indicate similar hydration by hydrogen-bond donor and acceptor waters. However, the new optimized SSDQO1 parameters as well as TIP4P-Ew and TIP5P predict a 'lone-pair' orientation for the water accepting the sugar hydroxyl hydrogen bond that is more consistent with the limited experimental data than the 'dipole' orientation in SPC/E, which has important implications for studies of the cryoprotectant properties of sugars.

  9. Deformation and energy absorption properties of powder-metallurgy produced Al foams

    Energy Technology Data Exchange (ETDEWEB)

    Michailidis, N., E-mail: nmichail@eng.auth.gr [Physical Metallurgy Laboratory (PML), Mechanical Engineering Department, Aristotle University of Thessaloniki, GR 54124 Thessaloniki (Greece); Stergioudi, F. [Physical Metallurgy Laboratory (PML), Mechanical Engineering Department, Aristotle University of Thessaloniki, GR 54124 Thessaloniki (Greece); Tsouknidas, A. [Mechanical Engineering Department, Technical University of Western Macedonia, 50100 Kozani (Greece)

    2011-09-15

    Highlights: {yields} Porous Al fabricated via a dissolution and sintering method using raw cane sugar. {yields} Different deformation mode depending on the relative density of the foams. {yields} Enhanced energy absorption by reducing pore size and relative density of the foam. {yields} Pore size uniformity and sintering temperature affect energy absorption. - Abstract: Al-foams with relative densities ranging from 0.30 to 0.60 and mean pore sizes of 0.35, 0.70 and 1.35 mm were manufactured by a powder metallurgy technology, based on raw cane sugar as a space-holder material. Compressive tests were carried out to investigate the deformation and energy absorbing characteristics and mechanisms of the produced Al-foams. The deformation mode of low density Al-foams is dominated by the bending and buckling of cell walls and the formation of macroscopic deformation bands whereas that of high density Al-foams is predominantly attributed to plastic yielding. The energy absorbing capacity of Al-foams rises for increased relative density and compressive strength. The sintering temperature of Al-foams having similar relative densities has a marked influence on both, energy absorbing efficiency and capacity. Pore size has a marginal effect on energy efficiency aside from Al-foams with mean pore size of 0.35 which exhibit enhanced energy absorption as a result of increased friction during deformation at lower strain levels.

  10. Deformation and energy absorption properties of powder-metallurgy produced Al foams

    International Nuclear Information System (INIS)

    Highlights: ? Porous Al fabricated via a dissolution and sintering method using raw cane sugar. ? Different deformation mode depending on the relative density of the foams. ? Enhanced energy absorption by reducing pore size and relative density of the foam. ? Pore size uniformity and sintering temperature affect energy absorption. - Abstract: Al-foams with relative densities ranging from 0.30 to 0.60 and mean pore sizes of 0.35, 0.70 and 1.35 mm were manufactured by a powder metallurgy technology, based on raw cane sugar as a space-holder material. Compressive tests were carried out to investigate the deformation and energy absorbing characteristics and mechanisms of the produced Al-foams. The deformation mode of low density Al-foams is dominated by the bending and buckling of cell walls and the formation of macroscopic deformation bands whereas that of high density Al-foams is predominantly attributed to plastic yielding. The energy absorbing capacity of Al-foams rises for increased relative density and compressive strength. The sintering temperature of Al-foams having similar relative densities has a marked influence on both, energy absorbing efficiency and capacity. Pore size has a marginal effect on energy efficiency aside from Al-foams with mean pore size of 0.35 which exhibit enhanced energy absorption as a result of increased friction during deformation at lower strain levels.

  11. Optimization of deformation conditions of VT-6 titanium alloy with the aim of improving of its mechanical properties

    International Nuclear Information System (INIS)

    Thermomechanical processing of the VT-6 titanium alloy using the effect of superplasticity is investigated. Rolling of the VT-6 alloy was carried out with 10-15% reduction per passage at 880-1000 deg C. After rolling all the samples were hardened and aged. Polynomial models of the second order are simulated by means of the LINRA program (linear regression analysis) for determination of optimum rolling regimes of the VT-6 alloy to obtain some service properties of material at room temperature. It is shown that the optimum regimes of rolling of the VT-6 titanium alloy from the view point of attaining maximum strength and ductility are as follows: rolling temperature 960+-10 deg C; degree of deformation 40+-5% per passage, deformation rate -1

  12. Molecular mechanics simulation on the deformation behaviors and the mechanical properties of nano composite of polyethylene and POSS

    Science.gov (United States)

    Hu, Enlai; Sun, Yi; Zeng, Fanlin

    2009-07-01

    The influence of polyhedral oligomeric silsesquioxane (POSS) on nano-hybrid materials has caused widespread attentions. In the current work, we investigate the deformation behaviors and the mechanical properties of the two kinds of polymers, polyethylene (PE) and PE copolymerized with vinyl-POSS (POSS-PE) by using molecular mechanics simulations. First, the nano scale atomistic models of the PE and POSS-PE incorporated with 25 wt% vinyl-POSS are built. With the aids of the COMPASS force field, the mechanical behaviors of the two kinds of polymers under different tensile strains are then simulated and the stress-strain curves are obtained. From the curve, the stresses and strains of PE keep approximately linear before the yield point. The corresponding tensile modulus is in good agreement with the experimental data. In addition, the simulation results show that the localized necking deformation appears during the yield process. It is believed that the slippage between the adjacent molecule chains is the chief source of such localized deformation. However, the necking phenomenon is not found in POSS-PE nano-composite. It seems that the POSS cages prevent the macromolecule chains from wide-spread slipping. The deformation is restrained locally around POSS monomers, thus leading to the formation of micro voids. We finally analyze the mechanical properties of the two kinds of polymers. The elastic modulus and tensile strength of POSS-PE have been remarkably improved. This work is significant to understand the reinforcement mechanism of POSS and provides important referential message to the applications of POSS.

  13. Characterization of properties in plastically deformed austenitic-stainless steels joined by friction welding

    International Nuclear Information System (INIS)

    Friction welding is widely used as a mass-production method in various industries. Welding is used for joining parts with equal and/or different diameters. Austenitic-stainless steels are preferred over other stainless steels due greater ease in welding. In the present study, an experimental set-up was designed in order to achieve friction welding of plastically deformed austenitic-stainless steels. AISI 304 austenitic-stainless steels having equal and different diameters were welded under different process parameters. Strengths of the joints having equal diameter were determined by using a statistical approach as a result of tension tests. Hardness variations and microstructures using scanning electron microscope (SEM) analysis in the welding zone were obtained and examined. Subsequently, the effects on the welding zone of plastic deformation was analysed. It has been established that plastic deformation of AISI 304 austenitic-stainless steel has neither an effect on the process nor on the strength of the welding joint

  14. Influence of plastic deformation on superconducting properties of V3Si single crystals

    International Nuclear Information System (INIS)

    Effects of the plastic deformation at elevated temperatures on the critical parameters Tsub(c) and jsub(c) of V3Si single crystals are reported. Plastic deformation can increase as well as decrease the critical temperature. The sign of the change in Tsub(c) can be attributed to different available point defect types on both sides from stoichiometry. In samples with excess V a decrease in Tsub(c) is observed combined with an increase of the electrical resistivity ratio r. The transition becomes broader and the critical current density increases with the deformation. In samples with excess Si the critical temperature is found to be increased as r decreases, at the same time the critical current density is lowered. (author)

  15. Fitting the flow curve of a plastically deformed silicon steel for the prediction of magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Sablik, M.J. [Southwest Research Institute, 6220 Culebra Rd, San Antonio, TX 78238-5166 (United States)]. E-mail: msablik@swri.org; Landgraf, F.J.G. [Metallurgy and Mat. Sci. Dept., Escola Politecnica da USP, 05508-970, Sao Paulo, SP (Brazil); Magnabosco, R. [UNIFEI, Sao Bernardo de Campo, SP (Brazil); Fukuhara, M. [Instituto Nacional de Metrologia INMETRO, Duque de Caxias, RJ (Brazil); Campos, M.F. de [Instituto Nacional de Metrologia INMETRO, Duque de Caxias, RJ (Brazil); Machado, R. [Instituto Nacional de Metrologia INMETRO, Duque de Caxias, RJ (Brazil); Missell, F.P. [Universidade de Caxias do Sul, Caxias do Sul, RS (Brazil)

    2006-09-15

    We report measurements and modelling of magnetic effects due to plastic deformation in 2.2% Si steel, emphasizing new tensile deformation data. The modelling approach is to take the Ludwik law for the strain-hardening stress and use it to compute the dislocation density, which is then used in the computation of magnetic hysteresis. A nonlinear extrapolation is used across the discontinuous yield region to obtain the value of stress at the yield point that is used in fitting Ludwik's law to the mechanical data. The computed magnetic hysteresis exhibits sharp shearing of the loops at small deformation, in agreement with experimental behavior. Magnetic hysteresis loss is shown to follow a Ludwik-like dependence on the residual strain, but with a smaller Ludwik exponent than applies for the mechanical behavior.

  16. Fitting the flow curve of a plastically deformed silicon steel for the prediction of magnetic properties

    International Nuclear Information System (INIS)

    We report measurements and modelling of magnetic effects due to plastic deformation in 2.2% Si steel, emphasizing new tensile deformation data. The modelling approach is to take the Ludwik law for the strain-hardening stress and use it to compute the dislocation density, which is then used in the computation of magnetic hysteresis. A nonlinear extrapolation is used across the discontinuous yield region to obtain the value of stress at the yield point that is used in fitting Ludwik's law to the mechanical data. The computed magnetic hysteresis exhibits sharp shearing of the loops at small deformation, in agreement with experimental behavior. Magnetic hysteresis loss is shown to follow a Ludwik-like dependence on the residual strain, but with a smaller Ludwik exponent than applies for the mechanical behavior

  17. Mica, deformation fabrics and the seismic properties of the continental crust

    Science.gov (United States)

    Lloyd, Geoffrey E.; Butler, Robert W. H.; Casey, Martin; Mainprice, David

    2009-10-01

    Seismic anisotropy originating within the continental crust is used to determine kinematic flow lines within active mountain belts and is widely attributed to regionally aligned mica. However, naturally deformed micaceous rocks commonly show composite (e.g. S-C) fabrics. It is necessary therefore to understand how both varying mica content and differing intensities of multiple foliations impact on seismic interpretations in terms of deformation fields. An outcrop analogue for granitic mid-crustal deformed zones is used here to calibrate the seismic response against both parameters. Seismic responses are modelled using crystallographic preferred orientations for polymineralic, micaceous granitic gneisses, measured using Electron Back-Scatter Diffraction. The sample results are generalised by modelling the effects of variations in modal composition and the relative importance of deformation fabrics of variable orientation, so-called rock and fabric recipes. The maximum P- and S-anisotropy are calculated at 16.6% and 23.9% for single-foliation gneisses but for mixed (i.e. S-C) foliation gneisses these values reduce to 5.8% and 7.5% respectively. Furthermore, mixtures of multiple foliations generate significant variations in the geometry of the seismic anisotropy. This effect, coupled with the geographical orientation of fabrics in nature, can generate substantial variations in the orientation and magnitude of seismic anisotropy (especially for shear waves) as measured for the continental crust using existing receiver function and teleseismic near-vertical incidence methods. Thus, maps of seismic anisotropy varying with depth in deforming continents need not imply necessarily depth-varying deformation kinematics and tectonic decoupling.

  18. Tensile elastic properties of 18:8 chromium-nickel steel as affected by plastic deformation

    Science.gov (United States)

    Mcadam, D J; Mebs, R W

    1939-01-01

    The relationship between stress and strain, and between stress and permanent set, for 18:8 alloy as affected by prior plastic deformation is discussed. Hysteresis and creep and their effects on the stress-strain and stress-set curves are also considered, as well as the influence of duration of the rest interval after cold work and the influence of plastic deformation on proof stresses, on the modulus of elasticity at zero stress, and on the curvature of the stress-strain line. A constant (c sub 1) is suggested to represent the variation of the modulus of elasticity with stress.

  19. Lattice Distortion and Octupole Ordering Model in CexLa1-xB6

    CERN Document Server

    Kubo, K; Kubo, Katsunori; Kuramoto, Yoshio

    2003-01-01

    Possible order parameters of the phase IV in CexLa1-xB6 are discussed with special attention to the lattice distortion recently observed. A \\Gamma_{5u}-type octupole order with finite wave number is proposed as the origin of the distortion along the [111] direction. The \\Gamma_8 crystalline electric field (CEF) level splits into three levels by a mean field with the \\Gamma_{5u} symmetry. The ground and highest singlets have the same quadrupole moment, while the intermediate doublet has an opposite sign. It is shown that any collinear order of \\Gamma_{5u}-type octupole moment accompanies the \\Gamma_{5g}-type ferro-quadrupole order, and the coupling of the quadrupole moment with the lattice induces the distortion. The cusp in the magnetization at the phase transition is reproduced, but the internal magnetic field due to the octupole moment is smaller than the observed one by an order of magnitude.

  20. Effect of fractional deformation during high-temperature thermomechanical treatment on the 18-10 type steel properties

    International Nuclear Information System (INIS)

    The effect of the number of passes on the rolling pressure, mechanical properties and the structure of chromium-nickel steels type 18-10 with titanium and varying carbon content, is studied. It is shown that the increase of fractional deformation during rolling brings about the improvement in the strength properties, keeping plastic properties sufficiently high. The increase in the carbon content leads to the acceleration of weakening processes at 1100-1150 deg C rolling temperature after 1-6 passes, while the opposite effect is observed with the temperature decrease and with the increase in the number of passes. The necessity of taking into account the residual hardening when calculating the rolling force, is pointed out

  1. Experimental evaluation of mechanical and electrical properties of RBC suspensions under flow. Role of RBC deformability.

    Czech Academy of Sciences Publication Activity Database

    Antonova, N.; ?íha, Pavel; Ivanov, I.; Gluhcheva, Y.; Bonchev, G.

    Munich : European Society for Clinical Hemorheology and Microcirculation, 2011. s. 13. [Conference of the European Society for Clinical Hemorheology and Microcirculation /16./, Annual Conference of the German Society for Clinical Microcirculation and Hemorheology /30./. 18.06.2011-21.06.2011, Munich] Institutional research plan: CEZ:AV0Z20600510 Keywords : red blood cells * electrical conductivity * deformability Subject RIV: BK - Fluid Dynamics

  2. Scale effects of nanomechanical properties and deformation behavior of Au nanoparticle and thin film using depth sensing nanoindentation

    Science.gov (United States)

    Maharaj, Dave

    2014-01-01

    Summary Nanoscale research of bulk solid surfaces, thin films and micro- and nano-objects has shown that mechanical properties are enhanced at smaller scales. Experimental studies that directly compare local with global deformation are lacking. In this research, spherical Au nanoparticles, 500 nm in diameter and 100 nm thick Au films were selected. Nanoindentation (local deformation) and compression tests (global deformation) were performed with a nanoindenter using a sharp Berkovich tip and a flat punch, respectively. Data from nanoindentation studies were compared with bulk to study scale effects. Nanoscale hardness of the film was found to be higher than the nanoparticles with both being higher than bulk. Both nanoparticles and film showed increasing hardness for decreasing penetration depth. For the film, creep and strain rate effects were observed. In comparison of nanoindentation and compression tests, more pop-ins during loading were observed during the nanoindentation of nanoparticles. Repeated compression tests of nanoparticles were performed that showed a strain hardening effect and increased pop-ins during subsequent loads. PMID:24991519

  3. Severe plastic deformation effect on mechanical properties and substructure of HfO2 nanoparticles bearing copper

    International Nuclear Information System (INIS)

    The effect of intense plastic deformation in the course of rolling on the temperature dependence of the ultimate strength of copper containing dispersed HfO2 nanoparticles was studied. The results of thermoactivation analysis of the experimental data showed that the introduction of HfO2 particles did not change the activation energy and, hence, the mechanism of fracture. The presence of dispersed nanoparticles is manifested primarily by an increase in the thermal stability of copper subgrains and their mutual misorientation. This leads to increasing thermal stability of the strength properties. Rolling significantly influences the elastic modulus of the dispersion-strengthened composite

  4. Screening and finite size corrections to the octupole and Schiff moments

    CERN Document Server

    Flambaum, V V

    2012-01-01

    Parity (P) and time reversal (T) violating nuclear forces create P, T -odd moments in expansion of the nuclear electrostatic potential. We derive expression for the nuclear electric octupole field which includes the electron screening correction (similar to the screening term in the Schiff moment). Then we calculate the Z alpha corrections to the Schiff moment which appear due to the finite nuclear size. Such corrections are important in heavy atoms with nuclear charge Z > 50. The Schiff and octupole moments induce atomic electric dipole moments (EDM) and P, T -odd interactions in molecules which are measured in numerous experiments to test CP-violation theories.

  5. Specifications of the octupole magnets required for the ATF2 ultra-low ß* lattice

    Energy Technology Data Exchange (ETDEWEB)

    Marin, E.; /SLAC; Modena, M.; /CERN; Tauchi, T.; Terunuma, N.; /KEK, Tsukuba; Tomas, R.; /CERN; White, G.R.; /SLAC

    2014-05-28

    The Accelerator Test Facility 2 (ATF2) aims to test the novel chromaticity correction for higher chromaticity lattices as the one of CLIC. To this end the ATF2 ultra-low ß* lattice is designed to vertically focus the beam at the focal point or usually referred to as interaction point (IP), down to 23 nm. However when the measured multipole components of the ATF2 magnets are considered in the simulations, the evaluated spot sizes at the IP are well above the design value. The designed spot size is effectively recovered by inserting a pair of octupole magnets. In this note we address the technical specifications required for these octupole magnets.

  6. Specifications of the octupole magnets required for the ATF2 ultra-low ?* lattice

    International Nuclear Information System (INIS)

    The Accelerator Test Facility 2 (ATF2) aims to test the novel chromaticity correction for higher chromaticity lattices as the one of CLIC. To this end the ATF2 ultra-low ?* lattice is designed to vertically focus the beam at the focal point or usually referred to as interaction point (IP), down to 23 nm. However when the measured multipole components of the ATF2 magnets are considered in the simulations, the evaluated spot sizes at the IP are well above the design value. The designed spot size is effectively recovered by inserting a pair of octupole magnets. In this note we address the technical specifications required for these octupole magnets

  7. 'Staggering' effect in even-even nuclei with quadrupole and octupole deformations

    International Nuclear Information System (INIS)

    The ?I = 1 'staggering' effect is investigated in the energy spectrum of positive and negative parities of the yrast band of even-even actinide nuclei. It is shown that the 'staggering' effect is characterized by the 'zigzag' behavior and does not vanish within the observed range of angular momenta.

  8. ?I = 1 'staggering' effect in even-even nuclei with quadrupole and octupole deformations

    International Nuclear Information System (INIS)

    ?I = 1 'staggering' effect in the energy spectrum of the positive and negative parity of the yrast-band of the even-even nuclei of the rare earth region is studied. The formula is used which proportional to discrete approximation of the fourth derivative of the function ?E(I). 'Staggering' effect exhibits 'zigzag' behavior and it does not vanishes within the limit of the observed angular moments. (authors)

  9. Tidal deformations of a spinning compact object

    CERN Document Server

    Pani, Paolo; Maselli, Andrea; Ferrari, Valeria

    2015-01-01

    The deformability of a compact object induced by a perturbing tidal field is encoded in the tidal Love numbers, which depend sensibly on the object's internal structure. These numbers are known only for static, spherically-symmetric objects. As a first step to compute the tidal Love numbers of a spinning compact star, here we extend powerful perturbative techniques to compute the exterior geometry of a spinning object distorted by an axisymmetric tidal field to second order in the angular momentum. The spin of the object introduces couplings between electric and magnetic deformations and new classes of induced Love numbers emerge. For example, a spinning object immersed in a quadrupolar, electric tidal field can acquire some induced mass, spin, quadrupole, octupole and hexadecapole moments to second order in the spin. The deformations are encoded in a set of inhomogeneous differential equations which, remarkably, can be solved analytically in vacuum. We discuss certain subtleties in defining the multipole mom...

  10. Creation of freestanding wrinkled nano-films with desired deformation properties by controlling the surface morphology of a sacrificial layer

    Science.gov (United States)

    Hirakata, Hiroyuki; Maruyama, Tomohiro; Yonezu, Akio; Minoshima, Kohji

    2013-05-01

    Various wrinkle patterns can be formed due to the buckling of a stiff thin film on a compliant substrate. However, most wrinkled films previously reported were fixed on a large deformable substrate and thereby the potential deformability of the film was mechanically constrained by the substrate. In this study, we developed a technique for forming various wrinkled structures on the surface of a sacrificial resin layer. Since the sacrificial layer can be subsequently removed with a solvent, freestanding wrinkled films are created using the sacrificial layer. We found that a wrinkled structure is formed on the surface of the layer by applying a compressive strain to the resin layer at the appropriate moment during the hardening process. The wrinkle pattern depends on the curing time and the timing of the straining in two in-plane orthogonal directions. In addition to conventional stripe and labyrinth patterns by simple uniaxial and equi-biaxial strains, respectively, it was found that independent biaxial strains induce interesting structures, such as an orthogonally ordered wrinkle pattern and a nonsymmetrical buckling structure, in which the stripe array produced by the first straining remains and many finer wrinkles appear in each stripe by the second straining in the orthogonal direction. We conducted tensile experiments for 300-nm-thick freestanding Cu films having these wrinkled structures. The wrinkled nano-films have a variety of mechanical properties: the stripe structure has extremely high deformability (more than 10% strain) and reversibility, the labyrinth structure shows planar isotropic deformation, and the nonsymmetrical buckling structure has an anisotropic modulus and strength. Finite element analysis on the wrinkle structures revealed that the local stress concentration dominates the fracture limits.

  11. Influence of Hot Deformation on Mechanical Properties and Microstructure of a Twin-Roll Cast Aluminium Alloy EN AW-6082

    Science.gov (United States)

    Grydin, O.; Stolbchenko, M.; Nürnberger, F.; Schaper, M.

    2014-03-01

    Thin strips of medium- and high-strength age-hardening aluminium alloys are widely used in the automotive industry. Reducing their production costs caused by high energy consumption is an actual challenge. The implementation of the twin-roll casting technology is promising. However, mechanical properties of directly cast high-alloyed thin aluminium strips are oftentimes inadequate to standard specifications. In this work, the influence of a hot deformation following a twin-roll cast strip process on the mechanical properties and microstructure is investigated. For this study strips of age-hardening aluminium alloy EN AW-6082—manufactured at a laboratory scaled twin-roll caster—were single-pass rolled at temperatures of 420 °C and true strains of up to 0.5. The mechanical properties of the as-cast and by different strains hot deformed material in the soft-annealed and age-hardened states were characterized by tensile tests. The results reveal that the twin-roll cast material features the necessary strength properties, though it does not meet the standard requirements for ductility. Furthermore, the required minimum strain during hot rolling that is necessary to ascertain the standard specifications has been determined. Based on micrographs, the uniformity of the mechanical properties and of the microstructure as a result of recrystallization due to hot metal forming and heat treatment were determined. A fine-grain microstructure and satisfactory material ductility after prior rolling with a true strain above 0.41 for the age-hardened state T6 and above 0.1 for the soft-annealed state O have been established.

  12. Force-deformation properties of artificial and natural foods for testing chewing efficiency.

    Science.gov (United States)

    Slagter, A P; van der Glas, H W; Bosman, F; Olthoff, L W

    1992-11-01

    The force-deformation characteristics of two artificial test foods (Optosil and Optocal) for measurements of food comminution during mastication were investigated in a bite simulator and compared with those of carrots and peanuts. The influence of cusp geometry was evaluated by use of a flat plate and three cusp forms. The forces at the yield point were lower for Optocal than for Optosil artificial test food. The forces needed for Optocal overlapped those needed for carrots and peanuts. The natural foods showed more variation in the force and percentage of deformation at the yield point than the artificial foods. The artificial foods reflected the differences in cusp form better than did the natural foods. The use of artificial foods fulfills a need for standardization and warrants consideration in studies of mastication. PMID:1432802

  13. Effect of precrystallization annealing on substructure and properties of quenched deformed BrB2 bronze

    International Nuclear Information System (INIS)

    The aim of the study has been to investigate the substructural changes that take place during the pre-recrystallization annealing of tempered beryllium BrB2 bronze. The BrB2 bronze tempered and deformed by rolling at room temperature was subjected to annealing at 300 deg C. The X-ray and electron microscopy analyses were used. Comparing the study results it became possible to drawn a conclusion that the main cause of the changing intensity of the texture maxima and the anisotropy of the elasticity limit is the redistribution of dislocations at the stage of the deformation return. The changes in the strength characteristics are accounted mainly by the decomposition of the oversaturated solid solution

  14. Deformation properties of Al-Mg alloy 5086 in laboratory and explosive tests

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, R.W.; Erickson-Natishan, M.A.; Wagenhofer, M. [Maryland Univ., College Park, MD (United States). Dept. of Mechanical Engineering; Chambers, G.P.; Sandusky, H.W.; Zerilli, F.J.

    2000-07-01

    Static and dynamic deformation test results were obtained for Al-Mg alloy 5086 material in various conditions in order to provide a constitutive equation for use in code computations of more complex explosive deformations. Conventional laboratory tensile tests showed interference of a reversed strain rate effect because of dynamic strain aging (DSA). The DSA behavior was confirmed for additional material conditions spanning the mechanical and thermal H32 processing treatment of as-supplied pipe stock. Influences of grain size and H32 treatment on yielding and subsequent strain hardening behaviors were evaluated. Split-Hopkinson pressure bar test results on related Al-Mg alloy 5083 material were employed in the determination of applicable constants in Zerilli-Armstrong (Z-A) constitutive equations. Use of the equations is reported here for description of shock-induced bulging of a water-filled pipe material in hydrocode validation tests. (orig.)

  15. Effect of aging and plastic deformation on the thermal and mechanical properties of the 20N34K5F invar

    International Nuclear Information System (INIS)

    Mechanical and thermal properties of invar 20N34K5F are studied after various heat and thermomechanical treatments including plastic deformation and carbide aging. The mechanical properties obtained are compared with analogous ones for invar N36K10T3 hardened in aging by dispersed intermetallics. Invars 20N34K5F and N36K10T3 have practically the same thermal properties. It is shown that three hardening treatments result in a higher strength for the last material. The one exception is a more high growth of ultimate strength and yield strength in alloy 20N34K5 due to cold plastic deformation

  16. $\\beta$-decay properties for neutron-rich Kr-Tc isotopes from deformed pn-QRPA calculations with realistic forces

    OpenAIRE

    Fang, Dong-liang; Brown, B. Alex; Suzuki, Toshio

    2012-01-01

    In this work we studied $\\beta$-decay properties for deformed neutron-rich nuclei in the region Z=36-43. We use the deformed pn-QRPA methods with the realistic CD-Bonn forces, and include both the Gamow-Teller and first-forbidden types of decays in the calculation. The obtained $\\beta$-decay half-lives and neutron-emission probabilities of deformed isotopes are compared with experiment as well as with previous calculations. The advantages and disadvantages of the method are ...

  17. Shear-wave splitting unmasks deformation properties in the Eastern Himalayan Syntaxis and Namcha Barwa region

    Science.gov (United States)

    Chen, C.; Chen, H.; Chuang, Y. L.; Chan, W. W.; Jiang, M.; Liang, W.

    2013-12-01

    The Himalayan orogen and the Tibetan Plateau resulted from the collision between the Indian Plate and Eurasian Plate. This young and active orogenic system provides excellent opportunities to examine the lithospheric deformation and various dynamic processes during continental collision. Of particular interest is the Eastern Himalayan Syntaxis, where the structures of the Himalayan range change abruptly, developing an 'indenter corner' at the edge of the two colliding plates. Previous GPS measurements in the broad areas of Tibet and the adjacent Sichuan Basin reveal a clockwise deformation pattern. These observations have led to the crustal flow model, among others, suggesting that the lower crust beneath Tibet is weak and thus moving toward southeast during the collision. However, it is unclear to what extent the surface deformation detected by GPS can represent the deformation and flow pattern in the underlying lithosphere. Seismic anisotropy, on the other hand, offers an effective means to infer the lithospheric deformation. The past decade has seen a series of deployments of broadband seismic arrays in the Himalaya-Tibet and surrounding regions that yield shear-wave splitting measurements indicating complexities in anisotropic parameters in this region. In this study, we perform shear-wave splitting analysis of teleseismic waveform data from 25 recently deployed broadband stations in the Namcha Barwa region. The analysis was operated on the SKS phase that travels through the Earth's core from the mantle, which is then radially polarized upon reentry. We apply a particle motion test with the cross-correlation method, in which the values of the rotation direction (phi) and the time lag (dt) are selected when the cross-correlation coefficient attains its maximum. Our preliminary results show a general NE-SW (61-66 degrees) fast axis of polarization direction to the west of Yarlung-Tsangpo River. The polarization direction appears to be roughly parallel to that of the Indian absolute plate motion. To the farther east, the fast axis wraps around the edge of the Himalayan syntaxis with a NW-SE orientation. Most of the stations yield delay times between 0.10 and 0.425 s, much lower compared to those obtained in the surrounding regions, suggesting possibly weaker anisotropy in this region. Nevertheless, our observations may argue for a mechanically coupled crust and lithospheric mantle at the suture region.

  18. The property of kappa-deformed statistics for a relativistic gas in an electromagnetic field: kappa parameter and kappa-distribution

    OpenAIRE

    Lina, Guo; Jiulin, Du; Zhipeng, Liu

    2007-01-01

    We investigate the physical property of the kappa parameter and the kappa-distribution in the kappa-deformed statistics, based on Kaniadakis entropy, for a relativistic gas in an electromagnetic field. We derive two relations for the relativistic gas in the framework of kappa-deformed statistics, which describe the physical situation represented by the relativistic kappa-distribution function, provide a reasonable connection between the parameter kappa, the temperature four-...

  19. Theory and measurement of properties of two-phase materials in the plastic-viscous deformation range

    International Nuclear Information System (INIS)

    An extensive literature survey shows, that theoretical equations available are inadequate to predict the viscosity of suspensions without limitation of the concentration of the dispersed phase, the shape and orientation of the suspended particles. Based on physically derived and experimentally verified equations for the theoretical prediction of transport and/or field properties of solid two-phase materials with penetration structure, an attempt has been made to predict the viscosity of suspensions and the high temperature creep of two-phase solid materials with the aid of so-called structure parameters. The justification for the treatment of the problem in such a way is given by the consideration of the viscocity as a transport property and by the existing analogies between viscous and viscoplastic deformation. (orig./RW)

  20. Geometrical and mechanical properties of the fractures and brittle deformation zones based on the ONKALO tunnel mapping, 2400 - 4390 m tunnel chainage

    Energy Technology Data Exchange (ETDEWEB)

    Moenkkoenen, H.; Rantanen, T.; Kuula, H. [WSP Finland Oy, Helsinki (Finland)

    2012-05-15

    In this report, the rock mechanics parameters of fractures and brittle deformation zones have been estimated in the vicinity of the ONKALO area at the Olkiluoto site, western Finland. This report is an extension of the previously published report: Geometrical and Mechanical properties if the fractures and brittle deformation zones based on ONKALO tunnel mapping, 0-2400 m tunnel chainage (Kuula 2010). In this updated report, mapping data are from 2400-4390 m tunnel chainage. Defined rock mechanics parameters of the fractures are associated with the rock engineering classification quality index, Q', which incorporates the RQD, Jn, Jr and Ja values. The friction angle of the fracture surfaces is estimated from the Jr and Ja numbers. There are no new data from laboratory joint shear and normal tests. The fracture wall compressive strength (JCS) data are available from the chainage range 1280-2400 m. Estimation of the mechanics properties of the 24 brittle deformation zones (BDZ) is based on the mapped Q' value, which is transformed to the GSI value in order to estimate strength and deformability properties. A component of the mapped Q' values is from the ONKALO and another component is from the drill cores. In this study, 24 BDZs have been parameterized. The location and size of the brittle deformation are based on the latest interpretation. New data for intact rock strength of the brittle deformation zones are not available. (orig.)

  1. Study of microstructural evolution, microstructure-mechanical properties correlation and collaborative deformation-transformation behavior of quenching and partitioning (Q and P) steel

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Jing; Yu, Hao, E-mail: yhzhmr@126.com; Wang, Shaoyang; Fan, Yongfei

    2014-02-24

    This paper presents a detailed characterization of the microstructural evolution of quenching and partitioning (Q and P) steel by dilatometer, X-ray diffraction and scanning electron microscopy. Influence of partitioning time on mechanical properties was investigated and the relationship between microstructures and mechanical properties was established. The results indicate that bainite transformation occurs at the preliminary stage of partitioning and the amount is proportional to quenching temperature. Martensite softening, bainite transformation kinetics, amount and stability of retained austenite collaboratively have effects on mechanical properties. The purpose of the EBSD investigation is to study the changes in the microstructure of the Q and P steel during deformation and obtain a better understanding of collaborative deformation-transformation behavior. During deformation, plastic deformation preferentially occurred in the vicinity of ferrite–martensite interfaces and spread to the interior of ferrite grain with strain increasing. Plastic deformation started to occur in martensite after large strain. Furthermore, grain rotation occurred in some austenite grains or divided into subgrains during deformation.

  2. Study of microstructural evolution, microstructure-mechanical properties correlation and collaborative deformation-transformation behavior of quenching and partitioning (Q and P) steel

    International Nuclear Information System (INIS)

    This paper presents a detailed characterization of the microstructural evolution of quenching and partitioning (Q and P) steel by dilatometer, X-ray diffraction and scanning electron microscopy. Influence of partitioning time on mechanical properties was investigated and the relationship between microstructures and mechanical properties was established. The results indicate that bainite transformation occurs at the preliminary stage of partitioning and the amount is proportional to quenching temperature. Martensite softening, bainite transformation kinetics, amount and stability of retained austenite collaboratively have effects on mechanical properties. The purpose of the EBSD investigation is to study the changes in the microstructure of the Q and P steel during deformation and obtain a better understanding of collaborative deformation-transformation behavior. During deformation, plastic deformation preferentially occurred in the vicinity of ferrite–martensite interfaces and spread to the interior of ferrite grain with strain increasing. Plastic deformation started to occur in martensite after large strain. Furthermore, grain rotation occurred in some austenite grains or divided into subgrains during deformation

  3. Examination of different strengths of octupole correlations in neutron-rich Pr and Pm isotopes.

    Czech Academy of Sciences Publication Activity Database

    Thiamova, G.; Alexa, P.; Hons, Zden?k; Simpson, G.S.

    2012-01-01

    Ro?. 86, ?. 4 (2012), 044334/1-044334/5. ISSN 0556-2813 R&D Projects: GA ?R GAP203/10/0310 Institutional support: RVO:61389005 Keywords : neutron rich nuclei * octupole correlations Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 3.715, year: 2012

  4. Influence of degree of deformation on anisotropy in mechanical properties in wrought magnesium alloy ZK60

    International Nuclear Information System (INIS)

    A direct-chill (DC) cast magnesium alloys ZK60 has been forward-extruded at 300 deg. C in a single pass at two extrusion ratios (ER) 12 and 44, which correspond to a total degree of deformation (f) of 2.5 and 3.8, respectively. The as-extruded microstructure in both cases consists of two colonies of grain sizes, i.e. about 15 mu m and 25 mu m) at higher extrusion ratios give significantly weaker strength differential effect (difference in tensile yield stress and compressive yield stress). (author)

  5. Note on a search for the two-octupole phonon 2+ state in 208 Pb with resonant photon scattering

    International Nuclear Information System (INIS)

    Results of a 208 Pb (?,?') experiment are presented aiming at an identification of the 2 + member of the long-sought two-octupole phonon multiplet. Four E2 excitations have been observed below 6.5 MeV excitation energy, two of them for the first time. However, in contrast to new results of calculations within the quasiparticle-phonon nuclear model (QPM), no obvious candidate for the two-octupole phonon vibration could be found in the present study. We discuss the J?=2+ states detected in this as well as previous experiments with respect to their possible two-octupole phonon structure

  6. The effect of post-deformation aging on superelastic properties of Ni{sub 50.9}Ti thin wires attaining micro and nano-substructure

    Energy Technology Data Exchange (ETDEWEB)

    Abbasi-Chianeh, V., E-mail: vahid61abbasi@gmail.com [Faculty of Mechanics Engineering, Urmia University of Technology, Urmia (Iran, Islamic Republic of); Research Center for Advanced Materials and Mineral Processing, Faculty of Materials Engineering, Sahand University of Technology, Tabriz (Iran, Islamic Republic of); Khalil-Allafi, J.; Kazemi-choobi, K. [Research Center for Advanced Materials and Mineral Processing, Faculty of Materials Engineering, Sahand University of Technology, Tabriz (Iran, Islamic Republic of)

    2013-06-25

    Highlights: ? Precipitation of Ni{sub 4}Ti{sub 3} during aging at 450 °C is hindered after severe cold work. ? Nanostructure formation improves the superelastic behavior of Ni-rich NiTi. ? Deformations less than 0.4 result in work hardening and reduce plateau strain. ? Deformations more than 0.4 yield in high stress and strain values of upper plateau. -- Abstract: Superelastic properties of Ni{sub 50.9}Ti shape memory wires were studied after cold drawing and post-deformation annealing at 450 °C. Characteristic transformation temperatures were determined using differential scanning calorimetry. Microstructural investigations were performed using optical and transmission electron microscopy. Results indicate that deformations more than 0.4 of true strain yield in high stress and high strain values of upper plateau. On the other hand, deformations less than 0.4 result in work hardening and reduce plateau strain. Post-deformation heat treatment at 450 °C leads to precipitation of Ni{sub 4}Ti{sub 3} particles and development of recovered microstructure in slightly cold drawn wires. Post-deformation annealing of wires with cold work value of 0.6 in true strain develop nanocrystalline microstructure and hindered the formation of Ni{sub 4}Ti{sub 3} precipitates. Precipitation of Ni{sub 4}Ti{sub 3} particles improves the superelastic properties of not cold drawn wires. However, in comparison with annealed and aged wires, severely deformed wires attain better superelastic properties after annealing at 450 °C without any Ni{sub 4}Ti{sub 3} precipitates.

  7. Thermal Stability and Properties of Deformation-Processed Cu-Fe In Situ Composites

    Science.gov (United States)

    Liu, Keming; Jiang, Zhengyi; Zhao, Jingwei; Zou, Jin; Lu, Lei; Lu, Deping

    2015-02-01

    This paper investigated the thermal stability, tensile strength, and conductivity of deformation-processed Cu-14Fe in situ composites produced by thermo-mechanical processing. The thermal stability was analyzed using scanning electronic microscope and transmission electron microscope. The tensile strength and conductivity were evaluated using tensile-testing machine and micro-ohmmeter, respectively. The Fe fibers in the deformation-processed Cu-14Fe in situ composites undergo edge recession, longitudinal splitting, cylinderization, break-up, and spheroidization during the heat treatment. The Cu matrix experiences recovery, recrystallization, and precipitation phase transition. The tensile strength and conductivity first increase with increasing temperature of heat treatment, reach peak values at different temperatures, and then decrease at higher temperatures. The value of parameter Z of the in situ composite reaches the peak of 2.86 × 107 MPa2 pct IACS after isothermal heat treatment at 798 K (525 °C) for 1 hour. The obtained tensile strength and conductivity of the in situ composites are 907 MPa and 54.3 pct IACS; 868 MPa and 55.2 pct IACS; 810 MPa and 55.8 pct IACS; or 745 MPa and 57.4 pct IACS, at ? = 7.8 after isochronal heat treatment for 1 hour.

  8. Low temperature acoustic properties of nanostructured zirconium prepared by the intensive plastic deformation technique

    International Nuclear Information System (INIS)

    The temperature dependences of the logarithmic decrement and dynamic Young's modulus in polycrystalline coarse-grained and nanostructured Zr have been studied in the temperature range of 2.5 to 340 K. The nanostructured state of the samples with a grain size of the order of 100 nm was attained during intensive plastic deformation (IPD). The measurements were carried out by the two-component vibrator technique at frequencies of 73-350 kHz. In the annealed coarse-grained Zr, an internal friction relaxation peak was observed close to 250 K which persisted even after IPD but its height increased by a factor of ten and the localization temperature shifted towards low temperatures. Moreover, after IPD a new internal friction peak was registered at moderately low temperatures near 80 K. Estimations of the activation parameters of the observed peaks are made. It is shown, that the peaks are caused by different thermo activated dislocation processes, namely, by interaction of dislocations with impurities and by formation of kink pairs in dislocations. It is established, that the intensive plastic deformation is accompanied by a considerable decrease (by 7-8%) in the Young's modulus caused by the quasistatic and dynamic dislocation effects. At T < 20 K, the nanostructured zirconium exhibited a glass-like anomaly in the temperature dependences of the Young's modulus of that may be responsible for by the tunneling and thermo activated relaxation of quasi-local excitations in disoaxation of quasi-local excitations in disordered solids.

  9. The Effect of Cooling Rate, and Cool Deformation Through Strain-Induced Transformation, on Microstructural Evolution and Mechanical Properties of Microalloyed Steels

    Science.gov (United States)

    Mousavi Anijdan, S. H.; Yue, Steve

    2012-04-01

    In this article, a detailed study was conducted to evaluate the microstructural evolution and mechanical properties of microalloyed steels processed by thermomechanical schedules incorporating cool deformation. Cool deformation was incorporated into a full scale simulation of hot rolling, and the effect of prior austenite conditioning on the cool deformability of microalloyed steels was investigated. As well, the effect of varying cooling rate, from the end of the finishing stage to the cool deformation temperature, 673 K (400 °C), on mechanical properties and microstructural evolution was studied. Transmission electron microscopy (TEM) analysis, in particular for Nb containing steels, was also conducted for the precipitation evaluation. Results show that cool deformation greatly improves the strength of microalloyed steels. Of the several mechanisms identified, such as work hardening, precipitation, grain refinement, and strain-induced transformation (SIT) of retained austenite, SIT was proposed, for the first time in microalloyed steels, to be a significant factor for strengthening due to the deformation in ferrite. Results also show that the effect of precipitation in ferrite for the Nb bearing steels is greatly overshadowed by SIT at room temperature.

  10. Influence of severe plastic deformation by the ECAP method on structure and properties of the P2-04BCh steel

    Directory of Open Access Journals (Sweden)

    M. Greger

    2009-05-01

    Full Text Available Purpose: Maim aim of this paper is to describe the plastic deformation executed by ECAE of low carbon steel. The ECAE method lead to significant improvement of strength of investigated material.Design/methodology/approach: Experiments were planned and realised an the temperature ranging from room temperature up 280oC. After application of deformation the structure was investigated in dependence on accumulation of deformation and deformation temperature as well as abovementioned final properties.Findings: Accumulated deformation varied from the value 2 to 8. Investigation of structure by electron microscopy was made with use microscope JEOL JEM 2100. Mechanical properties were investigated by tensile test. Statistic evaluation of angular disorientation and of size of grains/sub-grains was also made with use of electron diffraction (EBSD in combination with scanning electron microscope FEG SEM Philips.Practical implications: The technology ECAE was applied on low carbon steel. It was verification of ECAE application possibility on steel P2-04BCH importantly for following applying on similar kinds of steel, because ECAE deformation influence.Originality/value: The results from his work shall be useful in determining conditions for fabrication of nanocrystalline or sub-microcrystalline steel by the ECAE technology.

  11. Some properties of an infinite family of deformations of the harmonic oscillator

    International Nuclear Information System (INIS)

    In memory of Marcos Moshinsky, who promoted the algebraic study of the harmonic oscillator, some results recently obtained on an infinite family of deformations of such a system are reviewed. This set, which was introduced by Tremblay, Turbiner, and Winternitz, consists in some Hamiltonians Hk on the plane, depending on a positive real parameter k. Two algebraic extensions of Hk are described. The first one, based on the elements of the dihedral group D2k and a Dunkl operator formalism, provides a convenient tool to prove the superintegrability of Hk for odd integer k. The second one, employing two pairs of fermionic operators, leads to a supersymmetric extension of Hk of the same kind as the familiar Freedman and Mende super-Calogero model. Some connection between both extensions is also outlined.

  12. The effect of aluminium on mechanical properties and deformation mechanisms of hadfield steel single crystals

    Science.gov (United States)

    Zakharova, E. G.; Kireeva, I. V.; Chumlyakov, Y. I.; Shul'Mina, A. A.; Sehitoglu, H.; Karaman, I.

    2004-06-01

    On single crystals of Hadfield steel (Fe-13Mn-1.3C, Fe-13Mn-2.7Al-1.3C, wt.%) the systematical investigations of deformation mechanisms - slip and twinning, stages of plastic flow, strain hardening coefficient depending on orientation of tensile axis have been carried out by methods of optical and electron microscopy, x-ray analysis. Is has been shown that the combination of low stacking fault energy (?{SF}=0.03J/m^2) with high concentration of carbon atoms in aluminium-free steel results in development of the mechanical twinning at room temperature in all crystal orientations. The new type of twinning with formation of extrinsic stacking fault has been found out in [001] single crystals. Experimentally it has been established that alloying with aluminium leads to increase of stacking fault energy of Hadfield steel and suppresses twinning in all orientations of crystals at preservation of high values of strain-hardening coefficients ?.

  13. Magnetorheological and deformation properties of magnetically controlled elastomers with hard magnetic filler

    International Nuclear Information System (INIS)

    Viscoelastic and deformational behavior of soft magnetic elastomers with hard magnetic fillers under the influence of a magnetic field is studied by different experimental techniques. The magnetic elastomers used in this work were synthesized on the basis of silicone rubber filled with FeNdB particles and were magnetized in a field of 3 and 15 kOe. We have shown that due to high residual magnetization the materials demonstrate well pronounced non-elastic behavior already in the absence of any external magnetic field. In particular, in contrast to magnetic elastomers based on soft magnetic fillers their elastic modulus is strain-dependent. Under the influence of external magnetic field the storage and loss moduli of magnetic elastomers with hard magnetic filler can both increase and decrease tremendously.

  14. Magnetorheological and deformation properties of magnetically controlled elastomers with hard magnetic filler

    Science.gov (United States)

    Stepanov, G. V.; Chertovich, A. V.; Kramarenko, E. Yu.

    2012-10-01

    Viscoelastic and deformational behavior of soft magnetic elastomers with hard magnetic fillers under the influence of a magnetic field is studied by different experimental techniques. The magnetic elastomers used in this work were synthesized on the basis of silicone rubber filled with FeNdB particles and were magnetized in a field of 3 and 15 kOe. We have shown that due to high residual magnetization the materials demonstrate well pronounced non-elastic behavior already in the absence of any external magnetic field. In particular, in contrast to magnetic elastomers based on soft magnetic fillers their elastic modulus is strain-dependent. Under the influence of external magnetic field the storage and loss moduli of magnetic elastomers with hard magnetic filler can both increase and decrease tremendously.

  15. Bulk crustal properties in NE Tibet and its implication for deformation model

    Science.gov (United States)

    Tian, Xiaobo

    2014-05-01

    The crust beneath the northeastern (NE) Tibetan Plateau records far field effects of collision and convergence occurring between the Indian and Eurasian plates. A better structural understanding of the crust beneath NE Tibet can improve our understanding of Cenozoic deformation resulting from the India-Eurasia collision. Taking advantage of the relatively dense coverage in most areas in NE Tibet except for the Qaidam basin by regional seismic networks of Gansu and Qinghai Provinces, we isolate receiver functions from the teleseismic P wave data recorded from 2007 to 2009 and resolve the spatial distribution of crustal thickness and Vp/Vs ratio beneath NE Tibet from H-K scanning. Our results can be summarized as: (1) NE Tibet is characterized by ~ 60-km-thick crust beneath the Nan Shan, Qilian Shan thrust belts and the Anyemaqen Shan, and 45-50 km-thick crust beneath the Tarim basin, the Alashan depression and the Ordos basin; the crust thins gradually from west to east in addition to the previously observed pronounced thinning from south to north; (2) the crust of NE Tibet exhibits a relatively lower Vp/Vs ratio of 1.72 than the north China block and a decrease in average crustal Vp/Vs ratio with increasing crustal thickness; and (3) the crustal thicknesses are less than the values predicted by the simple isostatic model of throughout Tibetan plateau in where the elevation is larger than 3.0 km. Our observations can be explained by the hypothesis that deformation occurring in NE Tibet is predominated by upper-crustal thickening or lower-crust extrusion.

  16. Bilayer properties of giant magnetic liposomes formed by cationic pyridine amphiphile and probed by active deformation under magnetic forces.

    Science.gov (United States)

    Petrichenko, O; Erglis, K; C?bers, A; Plotniece, A; Pajuste, K; Béalle, G; Ménager, Ch; Dubois, E; Perzynski, R

    2013-01-01

    We synthesize giant magnetic liposomes by a reverse-phase evaporation method (REV) using a new self-assembling Cationic Pyridine Amphiphile (CPA) derived from 1,4-dihydropyridine as liposome-forming agent and a magnetic ferrofluid based on ?-Fe(2)O(3) nanoparticles. Having in view the potential interest of CPA in targeted transport by magnetic forces, the mechanical elastic properties of such bilayers are here directly investigated in vesicles loaded with magnetic nanoparticles. Bending elastic modulus K(b) ? 0.2 to 5k(B)T and pre-stress ? ? 3.2 to 12.10(-6) erg/cm(2) are deduced from the under-field deformations of the giant magnetic liposomes. The obtained K(b) values are discussed in terms of A. Wurgers's theory. PMID:23359032

  17. Effect of the Spinning Deformation Processing on Mechanical Properties of Al-7Si-0.3Mg Alloys

    Science.gov (United States)

    Cheng, Yin-Chun; Lin, Chih-Kuang; Tan, An-Hung; Hsu, Shih-Yuan; Lee, Sheng-Long

    2012-09-01

    This study investigates the mechanical properties of Al-7Si-0.3Mg (A356) alloy affected by the spinning deformation processing (SDP). The cast structure of the A356 alloy becomes elongated with increasing reduction in thickness. This leads to reduction of casting defects, and refines and distributes the eutectic silicon phase throughout the Al-matrix. The hardness tends to reach a steady value due to the uniformity of the microstructure with the reduction in thickness. The SDP leads to a re-arrangement in the eutectic region, which forces the propagation of cracks through the ductile ?-Al phase. The tensile strength and elongation increases accordingly. The improvement on tensile strength and elongation produces the best quality index for A356 alloy.

  18. Effect of deformation temperature on mechanical properties of ultrafine grained Al–Mg alloys processed by rolling

    International Nuclear Information System (INIS)

    Highlights: ? Mechanical properties and microstructural evolution of cryorolled + warm rolled (WR) Al 5083 alloy were investigated. ? WR samples showed a significant improvement in tensile strength and ductility (6.8%) than CR samples. ? WR sample is thermally stable up to 250 °C. ? YS and UTS of WR sample annealed at 250 °C are 270 MPa and 330 MPa, respectively, and elongation to failure is 13%. - Abstract: Aluminum–Magnesium (Al 5083) alloy was subjected to cryorolling (CR) and cryorolling followed by warm rolling (WR) in order to investigate the changes in mechanical behavior and microstructure evolution in the present work. Al alloy specimens were first cryorolled up to 50% thickness reduction followed with warm rolling at 100 °C, 145 °C, 175 °C and 200 °C till to achieve total 90% thickness reduction. The final microstructure of all conditions were analyzed and compared through transmission electron microscopy (TEM), Electron back scattered diffraction (EBSD), and X-ray diffraction (XRD) techniques to investigate the effect of WR deformation temperatures on mechanical properties. The mechanical behavior of the processed samples were evaluated through hardness and tensile tests performed at room temperature. An increase in yield strength (522 MPa), ultimate tensile strength (539 MPa) and ductility (6.8%) was observed in WR specimens at 175 °C, hardness also increases to (146 HV) as compared to CR samples. These samples were annealed in temperature range from 150 °C to 300 °C to investigate their thermal stability. The CR samples exhibited severely deformed structure with high dislocation density network while cryorolled followed by warm rolled (WR) samples has shown formation of ultrafine grains associated with dynamic recovery. At elevated temperature of 200 °C, WR samples showed decrease in strength accompanied with increase in elongation due to dominant dynamic recovery effect led to reduction in dislocation density

  19. Influence of Stress State, Stress Orientation, and Rock Properties on the Development of Deformation-Band 'Ladder' Arrays in Porous Sandstone

    Science.gov (United States)

    Schultz, R. A.; Soliva, R.; Fossen, H.

    2013-12-01

    Deformation bands in porous rocks tend to develop into spatially organized arrays that display a variety of lengths and thicknesses, and their geometries and arrangements are of interest with respect to fluid flow in reservoirs. Field examples of deformation band arrays in layered clastic sequences suggest that the development of classic deformation band arrays, such as ladders and conjugate sets, and the secondary formation of through-going faults appear to be related to the physical properties of the host rock, the orientation of stratigraphic layers relative to the far-field stress state, and the evolution of the local stress state within the developing array. We have identified several field examples that demonstrate changes in band properties, such as type and orientation, as a function of one or more of these three main factors. Normal-sense deformation-band arrays such as those near the San Rafael Swell (Utah) develop three-dimensional ladder-style arrays at a high angle to the maximum compression direction; these cataclastic shear bands form at acute angles to the maximum compression not very different from that of the optimum frictional sliding plane, thus facilitating the eventual nucleation of a through-going fault. At Orange quarry (France), geometrically conjugate sets of reverse-sense compactional shear bands form with angles to the maximum compression direction that inhibit fault nucleation within them; the bands in this case also form at steep enough angles to bedding that stratigraphic heterogeneities within the deforming formation were apparently not important. Two exposures of thrust-sense ladders at Buckskin Gulch (Utah) demonstrate the importance of host-rock properties, bedding-plane involvement, and local stress perturbations on band-array growth. In one ladder, thrust-sense shear deformation bands nucleated along suitably oriented bedding planes, creating overprinting sets of compaction bands that can be attributed to layer properties and local stress changes near the shear-band tips. Two other ladder exposures preserve compaction bands having nearly perpendicular orientations relative the bounding shear bands that define contractional stepovers that also nucleated on bedding planes. These cases suggest that local stress changes within a deformation-band stepover may lead to either rotation of bands or changes in band type relative to bands formed outside the stepover. The development of the common geometries of deformation band arrays, such as ladders, and the deformation paths to faulting thus depend on a combination of stress state, stress orientation, and rock properties.

  20. The influence of elastic deformation on the properties of the magnetoacoustic emission (MAE) signal for GO electrical steel

    Energy Technology Data Exchange (ETDEWEB)

    Piotrowski, Leszek, E-mail: lesio@mif.pg.gda.pl [Gdansk University of Technology, Gdansk 80-233 (Poland); Chmielewski, Marek; Augustyniak, Boleslaw [Gdansk University of Technology, Gdansk 80-233 (Poland)

    2012-08-15

    Magnetic properties of the grain oriented (GO) electrical steels are strongly affected by the stresses, both external and internal. The change is important even for the deformation resulting in stress level much lower than their yield limits. In this paper we present the results of investigation of the influence of compression and tension on the magnetoacoustic emission (MAE) signal properties. The experiment was performed with the help of bending machine in which the samples (0.3 mm thick, M140-30 S GO electrical steel) glued to the non-magnetic (austenitic steel) 8 mm thick bars were bent. The samples cut out in two directions (parallel and perpendicular to the rolling direction) were investigated. The elongation was measured directly with the help of tensometric bridge. Various parameters of the MAE signal, such as e.g. signal intensity and MAE peaks separation, have been examined. - Highlights: Black-Right-Pointing-Pointer Magnetic properties of the GO electrical steels are strongly affected by stress. Black-Right-Pointing-Pointer The non-destructive method of investigation of the ready-made components is needed. Black-Right-Pointing-Pointer Magnetoacoustic emission is sensitive to stress-induced domain structure changes. Black-Right-Pointing-Pointer Advanced signal analysis allows to determine the stress level in an unambiguous way.

  1. The influence of elastic deformation on the properties of the magnetoacoustic emission (MAE) signal for GO electrical steel

    International Nuclear Information System (INIS)

    Magnetic properties of the grain oriented (GO) electrical steels are strongly affected by the stresses, both external and internal. The change is important even for the deformation resulting in stress level much lower than their yield limits. In this paper we present the results of investigation of the influence of compression and tension on the magnetoacoustic emission (MAE) signal properties. The experiment was performed with the help of bending machine in which the samples (0.3 mm thick, M140-30 S GO electrical steel) glued to the non-magnetic (austenitic steel) 8 mm thick bars were bent. The samples cut out in two directions (parallel and perpendicular to the rolling direction) were investigated. The elongation was measured directly with the help of tensometric bridge. Various parameters of the MAE signal, such as e.g. signal intensity and MAE peaks separation, have been examined. - Highlights: ? Magnetic properties of the GO electrical steels are strongly affected by stress. ? The non-destructive method of investigation of the ready-made components is needed. ? Magnetoacoustic emission is sensitive to stress-induced domain structure changes. ? Advanced signal analysis allows to determine the stress level in an unambiguous way.

  2. Analysis on the Soil Dynamic Properties and Accumulated Deformation under the Rail Traffic Loads

    OpenAIRE

    Liwei Shen; Lei Chen; Haiyang Zhuang

    2014-01-01

    The dynamic behaviors of soil under the rail traffic load are obviously different from that under the other loads such as earthquake load and wave load. So the dynamic properties of soil under the rail traffic must be studied in specially. In this paper, the existing studies are summarized and analyzed in several aspects such as the dynamic properties of soil by testing, the constitutive model with considering the cyclic principal stress rotation, the calculated method for accumulated deforma...

  3. Enhancement of nuclear Schiff moments and time reversal violation in atoms due to soft nuclear octupole vibrations

    OpenAIRE

    Flambaum, V. V.; Zelevinsky, V. G.

    2002-01-01

    Parity and time invariance violating (${\\cal P},{\\cal T}$-odd) nuclear forces produce ${\\cal P},{\\cal T}$-odd nuclear moments, for example, the nuclear Schiff moment. In turn, this moment can induce electric dipole moments (EDMs) in atoms. We estimate the contribution to the Schiff moment from the soft collective octupole vibrations existing in many heavy nuclei. Two possible mechanisms are considered, mixing of the ground state of an odd-$A$ nucleus with the octupole phonon...

  4. Effect of hot deformation temperature on the magnetic and mechanical properties of Nd-Fe-B magnets prepared by spark plasma sintering

    International Nuclear Information System (INIS)

    The magnetic and mechanical properties of Nd-Fe-B magnets at different hot deformation temperatures have been investigated. The results showed that the optimum magnetic and mechanical properties and the highest crystallographic alignment of Nd-Fe-B magnets were obtained at 700 oC, and the possible reasons were analyzed. The microstructures show that abnormal grain growth is not observed at 650 oC; there exist many small spherical grains, and these small grains do not align during die upsetting. The average size of the grains and the volume fraction of coarse grains increase with increase in deformation temperature. The coarse grains do not align during die upsetting, and the non-alignment regions enlarge with increase in deformation temperature.

  5. Effect of hot deformation temperature on the magnetic and mechanical properties of Nd-Fe-B magnets prepared by spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Z.H., E-mail: huzhihua_1@163.co [College of Material Science and Engineering, Sichuan University, Chengdu 610065 (China); Li, J.; Chu, L.H.; Liu, Y. [College of Material Science and Engineering, Sichuan University, Chengdu 610065 (China)

    2011-01-15

    The magnetic and mechanical properties of Nd-Fe-B magnets at different hot deformation temperatures have been investigated. The results showed that the optimum magnetic and mechanical properties and the highest crystallographic alignment of Nd-Fe-B magnets were obtained at 700 {sup o}C, and the possible reasons were analyzed. The microstructures show that abnormal grain growth is not observed at 650 {sup o}C; there exist many small spherical grains, and these small grains do not align during die upsetting. The average size of the grains and the volume fraction of coarse grains increase with increase in deformation temperature. The coarse grains do not align during die upsetting, and the non-alignment regions enlarge with increase in deformation temperature.

  6. Radiation and helium effects on microstructures, nano-indentation properties and deformation behavior in ferrous alloys

    Science.gov (United States)

    Katoh, Y.; Ando, M.; Kohyama, A.

    2003-12-01

    Accelerated ion irradiation, especially 'dual-beam' irradiation, is a useful technique for experimental exploration of irradiation effects and validation of irradiation effect models, because of the unique controllability in irradiation conditions including the helium production rate. In this work, the effects of irradiation and helium implantation on microstructural evolution, hardness and plastic deformation behavior in Fe-15Cr-20Ni model austenitic ternary alloy and Fe-8 ˜ 9Cr-2W reduced-activation martensitic steels were studied through combined applications of ion irradiation, nano-indentation, focused ion-beam microprocessing and transmission electron microscopy. Systematic data on irradiation hardening are presented for broad irradiation conditions. Influences of helium implantation on irradiation-induced microstructural and nano-indentation hardness changes were not detected in the Fe-8 ˜ 9Cr-2W steels, while they were significant in the Fe-15Cr-20Ni alloy. The interaction behavior of dislocation loops with moving dislocations and the strength of the loops as obstacles to dislocation motion are also discussed for these two material classes based on the hardness, and the irradiated and indented microstructures.

  7. Radiation and helium effects on microstructures, nano-indentation properties and deformation behavior in ferrous alloys

    Energy Technology Data Exchange (ETDEWEB)

    Katoh, Y. E-mail: katohy@ornl.gov; Ando, M.; Kohyama, A

    2003-12-01

    Accelerated ion irradiation, especially 'dual-beam' irradiation, is a useful technique for experimental exploration of irradiation effects and validation of irradiation effect models, because of the unique controllability in irradiation conditions including the helium production rate. In this work, the effects of irradiation and helium implantation on microstructural evolution, hardness and plastic deformation behavior in Fe-15Cr-20Ni model austenitic ternary alloy and Fe-8 {approx} 9Cr-2W reduced-activation martensitic steels were studied through combined applications of ion irradiation, nano-indentation, focused ion-beam microprocessing and transmission electron microscopy. Systematic data on irradiation hardening are presented for broad irradiation conditions. Influences of helium implantation on irradiation-induced microstructural and nano-indentation hardness changes were not detected in the Fe-8 {approx} 9Cr-2W steels, while they were significant in the Fe-15Cr-20Ni alloy. The interaction behavior of dislocation loops with moving dislocations and the strength of the loops as obstacles to dislocation motion are also discussed for these two material classes based on the hardness, and the irradiated and indented microstructures.

  8. Influence of plastic deformation on structure and mechanical properties of stainless steel type X5CrNi18-10

    Directory of Open Access Journals (Sweden)

    W. Ozgowicz

    2008-07-01

    Full Text Available Purpose: The paper analyzes the influence of the degree of cold deformation on the structure and mechanical properties of austenitic stainless steel X5CrNi18-10.Design/methodology/approach: The investigations included observations of the structure on a light microscope, researches of mechanical properties in a static tensile test and microhardness measurements. The analysis of the phase composition was carried out on the basis of X-ray researches. In the qualitative X-ray analysis the comparative method was applied.Findings: Plastic deformation in deep drawing process of container from investigated austenitic stainless steel induced in its structure martensitic transformation ? ? ?’.Research limitations/implications: The X-ray phase analysis in particular permitted to disclose and identify the main phases on the structure of the investigated steel after its deformation within the range 10%÷50%.Practical implications: The analysis of the obtained results permits to state that the degree of deformation has a significant influence on the structure and mechanical properties of the investigated steels. Besides, a good correlation was found between changes of the structure and the effects of investigations of the mechanical properties.Originality/value: The analytic dependence of the yield point of the investigated steel on the draft degree in deep pressing process has been confirmed. Revealing this relation is of essential practical importance for the technology of sheetmetal forming of austenitic steel.

  9. The mechanical properties, deformation and thermomechanical properties of alkali treated and untreated Agave continuous fibre reinforced epoxy composites

    International Nuclear Information System (INIS)

    Research highlights: ? New renewable and biodegradable Agave americana fibre. ? Environmentally free materials. ? Good mechanical properties of Agave fibre reinforced epoxy composite materials. ? Surface modification of the fibre (Alkali treatment) imported good mechanical properties. ? Future scope in light weight materials manufacture. -- Abstract: The mechanical properties such as tensile, compressive, flexural, impact strength and water absorption of the alkali treated continuous Agave fibre reinforced epoxy composite (TCEC) and untreated continuous Agave fibre reinforced epoxy composite (UTCEC) were analysed. A comparison of the surfaces of TCEC and UTCEC composites was carried out by dynamic mechanical analysis (DMA), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The thermomechanical properties of the composite reinforced with sodium hydroxide (NaOH) treated Agave fibres were considerably good as the shrinkage of the fibre during alkali treatment had facilitated more points of fibre resin interface. The SEM micrograph and FTIR spectra of the impact fracture surfaces of TCEC clearly demonstrate the better interfacial adhesion between fibre and the matrix. In both analyses the TCEC gave good performance than UTCEC and, thus, there is a scope for its application in light weight manufacture in future.

  10. Effect of Temperature and Deformation Rate on the Tensile Mechanical Properties of Polyimide Films

    Science.gov (United States)

    Moghazy, Samir F.; McNair, Kevin C.

    1996-01-01

    In order to study the structure-property relationships of different processed oriented polyimide films, the mechanical properties will be identified by using tensile tester Instron 4505 and structural information such as the 3-dimensional birefringence molecular symmetry axis and 3-dimensional refractive indices will be determined by using wave guide coupling techniques. The monoaxial drawing techniques utilized in this research are very useful for improving the tensile mechanical properties of aromatic polyimide films. In order to obtain high modulus/high strength polyimide films the following two techniques have been employed, cold drawing in which polyimide films are drawn at room temperature at different cross head speeds and hot drawing in which polyimide films are drawn at different temperatures and cross head speeds. In the hot drawing process the polyimide films are drawn at different temperatures until the glass transition temperature (Tg) is reached by using the environmental chamber. All of the mechanical and optical property parameters will be identified for each sample processed by both cold and hot drawing techniques.

  11. A deformable shell model study of the properties of CsCl

    International Nuclear Information System (INIS)

    The deformable shell model has been put to a stringent test by calculating the transition temperature for transition of CsCl crystal from the CsCl-to the NaCl-structure. Because of the very small heat of transition this calculation is a very sensitive test of the model. Einstein approximation is used for estimating the thermal part of free energy. The transition temperature has been obtained by equating the Helmholtz free energy for the two phases at transition since the volume change accompanying transition is very small and the transition takes place at atmospheric pressure. The static lattice energy expression used for computing the free energy is obtained from the effective interaction including the many body interaction. The equation of state has also been calculated using the relation -P = (deltaF/deltaV)sub(T), as a further test of the validity of the model. Finally, the same model has been used to improve upon the lattice dynamical calculation by incorporating the effect of the polarizability of Cs+ ion on the phonon dispersion curves. The nearest neighbour distance at room temperature and at transition point in the CsCl-phase comes out within 0.1% of the experimental values. These have been determined for any particular temperature by minimizing the Helmholtz free energy at that temperature. The transition temperature has been reproduced almost exactly and in the calculation of the equation of state, the agreement with experiment is within 8% even reement with experiment is within 8% even at the highest compression. It has also been found that the inclusion of the positive ion polarizability improves the phonon dispersion curves of Ghosh and Basu remarkably with relatively a few number of parameters. The only remaining notable discrepancy is reported at the zone boundary along (110) direction for both the L.O. and T.O. branches and those too are found to be 5.2% and 4.6% respectively. (K.B.)

  12. Influence of plastic deformation on structure and mechanical properties of stainless steel type X5CrNi18-10

    OpenAIRE

    Ozgowicz, W.; Kalinowska-ozgowicz, E.; Kurc, A.

    2008-01-01

    Purpose: The paper analyzes the influence of the degree of cold deformation on the structure and mechanical properties of austenitic stainless steel X5CrNi18-10.Design/methodology/approach: The investigations included observations of the structure on a light microscope, researches of mechanical properties in a static tensile test and microhardness measurements. The analysis of the phase composition was carried out on the basis of X-ray researches. In the qualitative X-ray analysis the comp...

  13. Effect of deformation-induced martensite on the microstructure, mechanical properties and corrosion resistance of X5CrNi18-8 stainless steel

    OpenAIRE

    Ozgowicz, W.; Kurc, A.; Kciuk, M.

    2010-01-01

    Purpose: The aim of the paper was to determine the effect of deformation-induced martensite on the microstructure, mechanical properties and corrosion resistance of X5CrNi18-8 austenitic steel.Design/methodology/approach: The investigations included observations of the microstructure on a light microscope, researches of mechanical properties in a static tensile test, microhardness measurements made by Vickers’s method and corrosion resistance test examined using weight method. The analysis ...

  14. Multiparticle and octupole couping effects in translead Po and Rn nuclei

    International Nuclear Information System (INIS)

    Full text: Yrast high spin states in nuclei near the doubly magic 208pb core often have a relatively structure in terms of the coupling of the valence orbitals. This is in part due the availability of high-j orbitals for both the protons and neutrons, but it is also due to coupling of particle excitations to the collective octupole vibrational excitation, thus selectively lowering the energy of specific configurations. The results of a study of the high spin structure of the isotope 210Rn will be presented. The understanding of the structure of the highest states in this system are complicated by the presence of neutron hole excitations. Very recent results aimed at populating high spin, octupole mixed states in 212Po obtained using the SPIRAL facility will also be covered. Copyright (2005) Australian Institute of Physics

  15. Lower hybrid heating associated with mode conversion on the Wisconsin octupole

    International Nuclear Information System (INIS)

    This thesis addresses the following key issues in the lower hybrid frequency range: (1) what are the important physics aspects of wave propagation and heating in an experimental situation; (2) how effective is plasma heating in the complex magnetic field configuration of the octupole. Experimental work is accomplished by launching 1-10 ms pulses of up to 40 kW of radio frequency power at 140 MHz corresponding to the hot plasma lower hybrid resonance in the octupole. A dipole antenna which is moveable radially and is also rotatable couples wave power to the plasma. Coupling efficiencies greater than 95% are achieved by proper antenna placement near the edge of the plasma radial density profile

  16. High spin octupole correlations in the N=85, 139Xe and 141Ba isotones

    International Nuclear Information System (INIS)

    High spin states in 139Xe and 141Ba have been investigated using ?-? - and ?-?-?-coincidence studies of spontaneous fission of 252Cf. Alternating parity bands built on a 7/2-level are assigned up to spin I=(37/2) and I=(29/2) in 139Xe and 141Ba, respectively. Another possible octupole band based on ?i132(f7/2)2 multiplet with spin up to (29/2) also is observed in both nuclei. Cascades of enhanced E1 transitions and B(E1)/B(E2) ratios indicate strong octupole correlations. Systematics of the ?(f7/2)3, ?(f7/2)3x3- and ?u13/2(f7/2)2 multiplets and bands in N 85 isotones are presented. (author). Letter-to-the-editor

  17. Fragmentation of the low-energy octupole resonance in 48Ca, 90Zr, and 208Pb

    International Nuclear Information System (INIS)

    The fine structure of the low-energy octupole resonance was studied for 48Ca, 90Zr, and 208Pb by proton inelastic scattering at E/sub p/ = 65 MeV. The low-energy octupole resonance was composed of many discrete levels of L = 3 states. The total energy-weighted sum rule fraction of more than 10% was found in every nucleus. Especially in 208Pb, the energy-weighted sum rule fraction amounted to 15%. The strength was finely fragmented in 90Zr, but less fragmented in 208Pb. It is suggested that the ''degree of fragmentation'' is correlated with the excitation energy and the distribution of the low-lying quadrupole phonon states

  18. Investigation of octupole vibrational states in 150Nd via inelastic proton scattering (p,p'g)

    CERN Document Server

    Elvers, M; Ahmed, T; Ahn, T; Anagnostatou, V; Cooper, N; Deng, C; Endres, J; Goddard, P; Heinz, A; Ilie, G; Jiang, E; Kueppersbusch, C; Radeck, D; Savran, D; Shenkov, N; Werner, V; Zilges, A

    2011-01-01

    Octupole vibrational states were studied in the nucleus $^{150}\\mathrm{Nd}$ via inelastic proton scattering with $\\unit[10.9]{MeV}$ protons which are an excellent probe to excite natural parity states. For the first time in $^{150}\\mathrm{Nd}$, both the scattered protons and the $\\gamma$ rays were detected in coincidence giving the possibility to measure branching ratios in detail. Using the coincidence technique, the $B(E1)$ ratios of the decaying transitions for 10 octupole vibrational states and other negative-parity states to the yrast band were determined and compared to the Alaga rule. The positive and negative-parity states revealed by this experiment are compared with Interacting Boson Approximation (IBA) calculations performed in the (spdf) boson space. The calculations are found to be in good agreement with the experimental data, both for positive and negative-parity states.

  19. Measurements of octupole collectivity in Rn and Ra nuclei using Coulomb excitation

    CERN Multimedia

    We propose to exploit the unique capability of HIE-ISOLDE to povide post-accelerated $^{221,222}$Rn and $^{222,226,228}$Ra ion beams for the study of octupole collectivity in these nuclei. We will measure E3 transition momnets in $^{222}$Rn and $^{222,226,228}$Ra in order to fully map out the variation in E3 strengh in the octupole mass region with Z~88 and N~134. This will validate model calculations that predict different behaviour as a function of N. We will also locate the position of the parity doublet partner of the ground state in $^{221}$Rn, in order to test the suitability of odd-A radon isotopes for EDM searches.

  20. Lower hybrid heating associated with mode conversion on the Wisconsin octupole

    Energy Technology Data Exchange (ETDEWEB)

    Owens, T.L.

    1979-08-01

    This thesis addresses the following key issues in the lower hybrid frequency range: 1. What are the importent physics aspects of wave propagation and heating in an experimental situation. 2. How effective is plasma heating in the complex magnetic field configuration of the octupole. Experimental work is accomplished by launching 1-10ms pulses of up to 40kW of radio frequency power at 140MHz corresponding to the hot plasma lower hybrid resonance in the octupole. A diploe antenna which is moveable radially and is also rotatable couples wave power to the plasma. Coupling efficiencies greater than 95% are achieved by proper antenna placement near the edge of the plasma radial density profile.

  1. Mixed-symmetry octupole and hexadecapole excitations in the N=52 isotones

    CERN Document Server

    Hennig, A; Werner, V; Ahn, T; Anagnostatou, V; Cooper, N; Derya, V; Elvers, M; Endres, J; Goddard, P; Heinz, A; Huges, R O; Ilie, G; Mineva, M N; Petkov, P; Pickstone, S G; Pietralla, N; Radeck, D; Ross, T J; Savran, D; Zilges, A

    2015-01-01

    Background: Excitations with mixed proton-neutron symmetry have been previously observed in the $N=52$ isotones. Besides the well established quadrupole mixed-symmetry states (MSS), octupole and hexadecapole MSS have been recently proposed for the nuclei $^{92}$Zr and $^{94}$Mo. Purpose: The heaviest stable $N=52$ isotone $^{96}$Ru was investigated to study the evolution of octupole and hexadecapole MSS with increasing proton number. Methods: Two inelastic proton-scattering experiments on $^{96}$Ru were performed to extract branching ratios, multipole mixing ratios, and level lifetimes. From the combined data, absolute transition strengths were calculated. Results: Strong $M1$ transitions between the lowest-lying $3^-$ and $4^+$ states were observed, providing evidence for a one-phonon mixed-symmetry character of the $3^{(-)}_2$ and $4^+_2$ states. Conclusions: $sdg$-IBM-2 calculations were performed for $^{96}$Ru. The results are in excellent agreement with the experimental data, pointing out a one-phonon he...

  2. Contribution to the study of mechanical properties of nuclear fuel: atomistic modelling of the deformation of uranium dioxide

    International Nuclear Information System (INIS)

    Mechanical properties of nuclear fuel are a complex problem, involving many coupled mechanisms occurring at different length scales. We used Molecular Dynamics models to bring some light on some of these mechanisms at the atomic scale. We devised a procedure to calculate transition pathways between some UO2 polymorphs, and then carried out dynamics simulations of these transitions. We confirmed the stability of the cotunnite structure at high pressure using various empirical potentials, the fluorite structure being the most stable at room pressure. Moreover, we showed a reconstructive phase transition between the fluorite and cotunnite structures. We also showed the importance of the major deformation axis on the kind of transition that occur under tensile conditions. Depending on the loading direction, a scrutinyite or rutile phase can appear. We then calculated the elastic behaviour of UO2 using different potentials. The relative agreement between them was used to produce a set of parameters to be used as input in mesoscale models. We also simulated crack propagation in UO2 single crystals. These simulations showed secondary phases nucleation at crack tips, and hinted at the importance thereof on crack propagation at higher length-scales. We then described some properties of edge dislocations in UO2. The core structures were compared for various glide planes. The critical resolved shear stress was calculated for temperatures up to 2000 K. These calculations showed a link between lattice disorder at the dislocations core and the dislocations mobility. (author)

  3. Influence of Microstructure, Produced by Heat Treatment and Sever Plastic Deformation, on Tribological Properties of Low-carbon Steel

    Directory of Open Access Journals (Sweden)

    V. I. Semenov

    2011-06-01

    Full Text Available This paper presents the results of tribological investigations conducted on steel 20 with the carbon content of up to 0.2%. The steel was studied in the three conditions: initial (hot-rolled, after heat-treatment (quenching+tempering and after heat treatment with subsequent severe plastic deformation (SPD performed by equal channel angular pressing technique (ECAP. It was stated that after various treatments the material acquires various structural conditions and possesses various strength properties and has a considerable difference in oxygen content in the surface layer. This influences the tribological properties during the contact with tool steel. The lowest values of adhesive bond shear strength, friction coefficient and wear rate are demonstrated in the material after martempering with subsequent SPD by ECAP technique. The surface of the investigated material after SPD treatment by the ECAP technique possesses a highest bearing capacity and requires more time for wearing-in in friction assemblies. Oxygen content increase in the form of metal oxides on the surface of low-carbon steels is accompanied by a decrease of the adhesive component of friction coefficien.

  4. Carbon deposition during brittle rock deformation: Changes in electrical properties of fault zones and potential geoelectric phenomena during earthquakes

    Energy Technology Data Exchange (ETDEWEB)

    Mathez, E A; Roberts, J J; Duba, A G; Kronenberg, A K; Karner, S L

    2008-05-16

    To investigate potential mechanisms for geoelectric phenomena accompanying earthquakes, we have deformed hollow cylinders of Sioux quartzite to failure in the presence of carbonaceous pore fluids and investigated the resulting changes in electrical conductivity and carbon distribution. Samples were loaded at room temperature or 400 C by a hydrostatic pressure at their outer diameter, increasing pressure at a constant rate to {approx}290 MPa. Pore fluids consisted of pure CO, CO{sub 2}, CH{sub 4} and a 1:1 mixture of CO{sub 2} and CH{sub 4}, each with pore pressures of 2.0 to 4.1 MPa. Failure occurred by the formation of mode II shear fractures transecting the hollow cylinder walls. Radial resistivities of the cylinders fell to 2.9 to 3.1 M{Omega}-m for CO tests and 15.2 to 16.5 M{Omega}-m for CO{sub 2}:CH{sub 4} tests, compared with >23 M{Omega}-m for dry, undeformed cylinders. Carbonaceous fluids had no discernable influence on rock strength. Based on mapping using electron microprobe techniques, carbon occurs preferentially as quasi-continuous films on newly-formed fracture surfaces, but these films are absent from pre-existing surfaces in those same experiments. The observations support the hypothesis that electrical conductivity of rocks is enhanced by the deposition of carbon on fracture surfaces and imply that electrical properties may change in direct response to brittle deformation. They also suggest that the carbon films formed nearly instantaneously as the cracks formed. Carbon film deposition may accompany the development of microfracture arrays prior to and during fault rupture and thus may be capable of explaining precursory and coseismic geoelectric phenomena.

  5. Petrophysical Properties of Sandstones Containing Deformation Bands Versus Those With Fractures: the Importance of Grain Contact Strength to Fault-Zone Structure

    Science.gov (United States)

    Schneider, J. R.; Tobin, H. J.; Goodwin, L. B.

    2010-12-01

    In upper crustal fault zones, the majority of slip accumulates within a fault core, which is surrounded by a less deformed damage zone. Both the width and structural character of the damage zone affect its mechanical and hydrologic properties. Fault-related deformation can change rock mechanical properties, causing stress orientations to rotate in fault damage zones, and affecting seismicity over time. In addition, the types, densities, and orientations of structures in fault zones exert a first-order control on fault-zone permeability structure, permeability anisotropy, and flow pathways. For example, open-fracture damage zones enhance fault-parallel flow, whereas cataclastic deformation band networks slow flow in every direction except parallel to the line of intersection between bands. To improve our understanding of controls on damage zone character, we explored relationships between fault-zone structure and lithologic characteristics such as porosity and cement mineralogy in faulted quartz-rich sandstones. The sandstones chosen from fault sites in the Jurassic Navajo and Entrada sandstones in Utah, and the Cretaceous Mesaverde sandstone in Wyoming, exhibit a wide range in porosity. Samples collected include even greater variability in cements, from clay coatings on grains to patchy carbonate cement to grain-bridging quartz overgrowths and iron oxide cements. These variables demonstrably influence damage zone character, resulting in fractures in some locations and deformation bands in others (even within a single fault zone) and affecting deformation-band damage zone width. They likely influenced grain-contact strength also. Because ultrasonic velocity and related elastic moduli also vary with grain-contact strength, we measured P and S wave velocities as a function of confining pressure to 20 MPa as a sensitive proxy for grain-contact strength. More than 40 samples, including both host rock and rock with deformation bands, have been analyzed. Samples containing deformation bands display different ultrasonic velocities than adjacent samples lacking deformation bands. These data are used to evaluate the relative importance of the variables affecting deformation in clastic rocks. Establishing a quantitative link between fault structures, cements, porosity, and lithology and ultrasonic velocity will ultimately allow results to be directly applied to borehole geophysics and seismic reflection studies to improve prediction of fault-zone characteristics and fluid flow properties in quartz-rich sandstone reservoirs.

  6. Detailed spectroscopy of the doubly closed shell nucleus 132Sn: First observation of octupole collectivity

    International Nuclear Information System (INIS)

    The angular momenta and parities of the low-lying states of 132Sn have been firmly determined through studies of the ? decay of 132In. The lowest lying state with a negtive parity is shown to have a collective octupole character. Several particle-hole multiplets have been identified, including the lowest lying proton excitation. More than about 20% of the theoretically estimated bound states of 132Sn have been identified

  7. Possible experimental signature of octupole correlations in the 0$^+_2$ states of the actinides

    CERN Document Server

    Spieker, M; Endres, J; Faestermann, T; Hertenberger, R; Pascu, S; Skalacki, S; Weber, S; Wirth, H -F; Zamfir, N -V; Zilges, A

    2013-01-01

    $J^{\\pi}$= 0$^+$ states have been investigated in the actinide nucleus ${}^{240}$Pu up to an excitation energy of 3 MeV with a high-resolution (p,t) experiment at $E_{p}$= 24 MeV. To test the recently proposed $J^{\\pi}$= 0$^+_2$ double-octupole structure, the phenomenological approach of the spdf-interacting boson model has been chosen. In addition, the total 0$^+$ strength distribution and the $0^+$ strength fragmentation have been compared to the model predictions as well as to the previously studied (p,t) reactions in the actinides. The results suggest that the structure of the 0$^+_2$ states in the actinides might be more complex than the usually discussed pairing isomers. Instead, the octupole degree of freedom might contribute significantly. The signature of two close-lying 0$^+$ states below the 2-quasiparticle energy is presented as a possible manifestation of strong octupole correlations in the structure of the 0$^+_2$ states in the actinides.

  8. Deformation and fracture properties in neutron irradiated pure Mo and Mo alloys

    Science.gov (United States)

    Byun, T. S.; Li, M.; Cockeram, B. V.; Snead, L. L.

    2008-05-01

    The effect of neutron irradiation on the mechanical properties of select molybdenum materials, unalloyed low carbon arc-cast (LCAC) Mo, Mo-0.5% Ti-0.1% Zr (TZM) alloy, and oxide dispersion-strengthened (ODS) Mo alloy, was characterized by analyzing the temperature dependence of mechanical properties. This study assembles the tensile test data obtained through multiple irradiation and post-irradiation experiments, in which tensile specimens were irradiated up to 13.1 dpa at 80-1000 °C and tested at -194 to 1000 °C. Irradiation at 80-609 °C increased yield stress significantly, up to 170%, while the increase of yield stress after irradiation at 784-936 °C was not significant. The plastic instability stress was strongly dependent on test temperature but was nearly independent of irradiation dose and temperature. The true fracture stress showed weak dependences on test temperature, irradiation dose and temperature when ductile failure occurred. Among the test materials the stress-relieved ODS material in the longitudinal direction (ODS-LSR) displayed the highest resistance to irradiation embrittlement due to its relatively high fracture stress. The critical temperature for shear failure (CTSF) was defined and evaluated for the test materials and the CTSF values were compared with the ductile-to-brittle transition temperatures (DBTT) based on ductility data.

  9. Mechanical properties and microstructure evolution of 1050 aluminum severely deformed by ECAP to 16 passes

    International Nuclear Information System (INIS)

    Variation of mechanical properties and microstructure evolution in 1050 aluminum processed by equal channel angle pressing are investigated using Route BC and up to 16 passes. Micro hardness and compression testing were used to evaluate mechanical properties, whereas electron back scattered diffraction (EBSD) was used to document the variation of cell size and misorientation angle with number of passes. The hardness and yield strength exhibited an instant increase by a factor of about 2.75 and 2.96, respectively, compared to the annealed state, after only the first pass. It was found that the cell size gradually decreased with number of passes and attained an average value of about 0.6 ?m in the face plane (normal to the extrusion direction), and 0.85 ?m in the flow plane (parallel to the extrusion direction) after the sixteenth pass. The average misorientation angle evolved in both the face and flow planes ended up to about 27 deg. and 26 deg., respectively

  10. Geometrical and mechanical properties of the fractures and brittle deformation zones based on the ONKALO tunnel mapping, 4390-4990 m tunnel chainage and the technical rooms

    Energy Technology Data Exchange (ETDEWEB)

    Simelius, C. [Poeyry Finland Oy, Vantaa (Finland)

    2014-04-15

    In this report, the rock mechanics parameters of fractures and brittle deformation zones have been estimated in the vicinity of the ONKALO underground research facility at the Olkiluoto site, western Finland. This report is an extension of two previously published reports describing the geometrical and mechanical properties of the fractures and brittle deformation zones based on ONKALO tunnel mapping from tunnel chainages 0-2400 m (Kuula 2010) and 2400-4390 m (Moenkkoenen et al. 2012). This updated report makes use of mapping data from tunnel chainage 4390-4990 m, including the technical rooms located at the -420 m below the sea level. Analysis of the technical rooms is carried out by dividing the premises according to depth into three sections: the demonstration tunnel level, the technical rooms level and the -457 level. The division is executed in order to define the fracture properties in separate areas and to compare the properties with other technical rooms levels. Drillhole data from holes OL-KR1...OL-KR57 is also examined. This report ends the series of three parameterization reports. The defined rock mechanics parameters of the fractures are based on the rock engineering classification quality index, Q', which incorporates the RQD, Jn, Jr and Ja values. The friction angle of the fracture surfaces is estimated from the Jr and Ja numbers. No new data from laboratory joint shear and normal tests was available at the time of the report. The fracture wall compressive strength (JCS) data is available from the chainage range 1280-2400 m. New data for fracture wall compressive strength is not available although new Schmidt hammer measurements were performed in order to obtain the ratio of the intact rock mass vs. an intact brittle deformation zone. Estimation of the mechanical properties of the 23 brittle deformation zones (BDZ) is based on the mapped Q' value, which is converted into the GSI value in order to estimate the strength and deformability properties. Components of the mapped Q' values are either from the ONKALO or the drill cores depending on the availability of intersections. The location and size of the brittle deformation zones are based on the latest interpretation (Aaltonen et al. expected in 2014). New laboratory data for the intact rock strength of the brittle deformation zones is not available. (orig.)

  11. Mechanical properties and deformation mechanisms in Fe-xMn-3.2Al-0.2C (12?x?43) alloys

    International Nuclear Information System (INIS)

    Microstructure and mechanical properties of Fe-xMn-3,2 Al-0,23 C alloys with 12?x?43 (mass %) at 77 and 290 K have been studied to determine the mechanisms controlling plastic deformation. Austenitic alloys (Mn?22) show an increase of elongation to failure with decreasing temperature of testing (inverse ductility). This behavior has been related to deformation of deformation twins, which is favored at 77 K. Alloys with manganese content lower than 17% present a two-phase microstructure (?' + ?). The martensite volume fraction increases as the manganese content decreases. These alloys show a los of ductility, especially at 77 K. In contrast to austenitic alloys, this different mechanical behavior has been associated with a TRIP mechanism (transformation-induced plasticity). (Author) 11 refs

  12. Properties of the 15Kh1M1F heat treated steel after cold deformation

    International Nuclear Information System (INIS)

    Effect of cold plastic workina on properties of heat-treated 15Kh1M1F steel is studied. It is shown that after cold working the increase of the value of the ratio of yield strength to ultimate strength in the steel with ferrite-carbide structure (FCS) occurs in a considerably higher degree than in the steel with bainite structure (BS). Cold working of 15Kh1M1F steel with FCS results in considerable heterogeneity of impact strength, low values of which are at the level 40-150kJ/m2. After cold working and annealing of 15Kh1M1F steel with FCS at high-temperature loading weakens more intensively than the steel with BS. The rate of steady-state creep in 15Kh1M1F steel with FCS subjected to cold working and annealing is an order higher than in the steel with BS

  13. Mechanical Properties and Fractographic Analysis of High Manganese Steels After Dynamic Deformation Tests

    Directory of Open Access Journals (Sweden)

    Jab?o?ska M.B.

    2014-10-01

    Full Text Available Since few years many research centres conducting research on the development of high-manganese steels for manufacturing of parts for automotive and railway industry. Some of these steels belong to the group of AHS possessing together with high strength a great plastic elongation, and an ideal uniform work hardening behavior. The article presents the dynamic mechanical properties of two types of high manganese austenitic steel with using a flywheel machine at room temperature with strain rates between 5×102÷3.5×103s?–1. It was found that the both studied steels exhibit a high sensitivity Rm to the strain rate. With increasing the strain rate from 5×102 to 3.5×103s?–1 the hardening dominates the process. The fracture analysis indicate that after dynamic test both steel is characterized by ductile fracture surfaces which indicate good plasticity of investigated steels.

  14. Electrical and optical properties of stacking faults introduced by plastic deformation in 4H-SiC

    Energy Technology Data Exchange (ETDEWEB)

    Pichaud, B.; Regula, G. [Aix-Marseille Université, CNRS, IM2NP, UMR 7334, 13397, Marseille, France and Université de Toulon, CNRS, IM2NP, UMR 7334, 83957, La Garde (France); Yakimov, E. B. [Institute of Microelectronics Technology RAS, 142432, Chernogolovka (Russian Federation)

    2014-02-21

    The electrical and optical properties of stacking faults (SFs) introduced by plastic deformation in 4H-SiC were studied by Electron Beam Induced Current (EBIC) and cathodoluminescence (CL) methods. Partial dislocations and stacking faults in the (0001) glide planes perpendicular to the surface were introduced in n-type 4H-SiC under a well-controlled state of stress by cantilever bending at 550°C. CL measurements allow determining the multiplicity of the SFs (single or double). It is observed that the overwhelming majority of stacking faults are double Shockley type SFs (CL emission at 504 nm) that correlates well with previously published high resolution transmission electron microscopy (HRTEM) investigations. However, single Shockley type SFs (CL emission at 422 nm) of much smaller lengths are also observed in some areas near the scratched region from where the defects are nucleated. This suggests that the velocity of partial dislocation pairs under a given applied stress could be higher than that of single partial dislocations. It is also shown that in the EBIC mode, SFs produce a strong bright contrast, which can be explained by considering the SFs in 4H-SiC to be quantum wells of II type.

  15. Effect of Heat Treatment on the Thermoelectric Properties of Bismuth-Antimony-Telluride Prepared by Mechanical Deformation and Mechanical Alloying

    Science.gov (United States)

    Lee, Deuk-Hee; Lee, Jae-Uk; Jung, Sung-Jin; Baek, Seung-Hyub; Kim, Ju-Heon; Kim, Dong-Ik; Hyun, Dow-Bin; Kim, Jin-Sang

    2014-06-01

    In this work, p-type 20%Bi2Te3-80%Sb2Te3 bulk thermoelectric (TE) materials were prepared by mechanical deformation (MD) of pre-melted ingot and by mechanical alloying (MA) of elemental Bi, Sb, and Te granules followed by cold-pressing. The dependence on annealing time of changes of microstructure and TE properties of the prepared samples, including Seebeck coefficient, electrical resistivity, thermal conductivity, and figure-of-merit, was investigated. For both samples, saturation of the Seebeck coefficient and electrical resistivity were observed after annealing for 1 h at 380°C. It is suggested that energy stored in samples prepared by both MA and MD facilitated their recrystallization within short annealing times. The 20%Bi2Te3-80%Sb2Te3 sample prepared by MA followed by heat treatment had higher a Seebeck coefficient and electrical resistivity than specimens fabricated by MD. Maximum figures-of-merit of 3.00 × 10-3/K and 2.85 × 10-3/K were achieved for samples prepared by MA and MD, respectively.

  16. Electrical and optical properties of stacking faults introduced by plastic deformation in 4H-SiC

    International Nuclear Information System (INIS)

    The electrical and optical properties of stacking faults (SFs) introduced by plastic deformation in 4H-SiC were studied by Electron Beam Induced Current (EBIC) and cathodoluminescence (CL) methods. Partial dislocations and stacking faults in the (0001) glide planes perpendicular to the surface were introduced in n-type 4H-SiC under a well-controlled state of stress by cantilever bending at 550°C. CL measurements allow determining the multiplicity of the SFs (single or double). It is observed that the overwhelming majority of stacking faults are double Shockley type SFs (CL emission at 504 nm) that correlates well with previously published high resolution transmission electron microscopy (HRTEM) investigations. However, single Shockley type SFs (CL emission at 422 nm) of much smaller lengths are also observed in some areas near the scratched region from where the defects are nucleated. This suggests that the velocity of partial dislocation pairs under a given applied stress could be higher than that of single partial dislocations. It is also shown that in the EBIC mode, SFs produce a strong bright contrast, which can be explained by considering the SFs in 4H-SiC to be quantum wells of II type

  17. Microstructure, elastic deformation behavior and mechanical properties of biomedical ?-type titanium alloy thin-tube used for stents.

    Science.gov (United States)

    Tian, Yuxing; Yu, Zhentao; Ong, Chun Yee Aaron; Kent, Damon; Wang, Gui

    2015-05-01

    Cold-deformability and mechanical compatibility of the biomedical ?-type titanium alloy are the foremost considerations for their application in stents, because the lower ductility restricts the cold-forming of thin-tube and unsatisfactory mechanical performance causes a failed tissue repair. In this paper, ?-type titanium alloy (Ti-25Nb-3Zr-3Mo-2Sn, wt%) thin-tube fabricated by routine cold rolling is reported for the first time, and its elastic behavior and mechanical properties are discussed for the various microstructures. The as cold-rolled tube exhibits nonlinear elastic behavior with large recoverable strain of 2.3%. After annealing and aging, a nonlinear elasticity, considered as the intermediate stage between "double yielding" and normal linear elasticity, is attributable to a moderate precipitation of ? phase. Quantitive relationships are established between volume fraction of ? phase (V?) and elastic modulus, strength as well as maximal recoverable strain (?max-R), where the ?max-R of above 2.0% corresponds to the V? range of 3-10%. It is considered that the "mechanical" stabilization of the (?+?) microstructure is a possible elastic mechanism for explaining the nonlinear elastic behavior. PMID:25706668

  18. Influence of the pearlite fineness on the mechanical properties, deformation behavior, and fracture characteristics of carbon steel

    Science.gov (United States)

    Izotov, V. I.; Pozdnyakov, V. A.; Luk'yanenko, E. V.; Usanova, O. Yu.; Filippov, G. A.

    2007-05-01

    Specific features of plastic deformation and tensile failure of a plain carbon ( C = 0.62%) pearlitic-ferritic steel with various pearlite fineness have been investigated. It is shown that the steels with coarse lamellar pearlite and fine lamellar pearlite have similar strain-hardening coefficients, but the relative elongation of the former steel is higher. Deformation results in a uniform dislocation distribution in the fine pearlite and in the formation of a cellular substructure in the coarse pearlite. It is established that the fine pearlite undergoes plastic deformation and ductile failure as a single structure, while the coarse pearlite exhibits a structure discontinuity upon deformation. A model of microplastic pearlite deformation and the initial stage of macroplastic pearlite deformation is proposed. It is established that the strain-hardening coefficient of pearlite at the initial deformation stage does not depend on its dispersity. A size effect, which manifests itself in the dependence of the dislocation structure formed in the ferrite interlayers on their thickness, is shown to be characteristic of pearlite deformation.

  19. Predictability of hydraulic head changes and characterization of aquifer-system and fault properties from InSAR-derived ground deformation

    Science.gov (United States)

    Chaussard, E.; Bürgmann, R.; Shirzaei, M.; Fielding, E. J.; Baker, B.

    2014-08-01

    We evaluate the benefits of space-derived ground deformation measurements for basin-wide characterization of aquifer-system properties and groundwater levels. We use Interferometric Synthetic Aperture Radar (InSAR) time series analysis of ERS, Envisat, and ALOS SAR data to resolve 1992-2011 ground deformation in the Santa Clara Valley, California. T-mode principal component analysis successfully isolates temporally variable deformation patterns embedded in the multidecadal time series. The data reveal uplift at 0.4 cm/yr between 1992 and 2000 and < 0.1 cm/yr during 2000-2011, illustrating the end of the aquifer-system's poroelastic rebound following recovery of hydraulic heads after the 1960s low stand. In addition, seasonal elastic deformation with amplitude of up to 3 cm, in phase with head fluctuations, is observed over the confined aquifer sharply partitioned by the Quaternary Silver Creek Fault (SCF). Integration of this deformation with hydraulic head data enables characterization of the aquifer-system storativity and elastic skeletal specific storage. Modeling of the deformation partitioning across the SCF constrains the fault's last tectonic activity, hydraulic conductivity, and material composition. The SCF likely cuts the shallow confining clays and was last active since ~140 ka, it has a horizontal hydraulic conductivity several orders of magnitude lower than the surrounding aquifer-system, and is likely composed of clays, making it an effective barrier to across-fault fluid flow. Finally, we show that after a period of calibration, InSAR can be used to characterize basin-wide water level changes without well measurements with an accuracy of 70%, which demonstrates that it provides useful data for groundwater management.

  20. Effect of deformation-induced martensite on the microstructure, mechanical properties and corrosion resistance of X5CrNi18-8 stainless steel

    Directory of Open Access Journals (Sweden)

    W. Ozgowicz

    2010-05-01

    Full Text Available Purpose: The aim of the paper was to determine the effect of deformation-induced martensite on the microstructure, mechanical properties and corrosion resistance of X5CrNi18-8 austenitic steel.Design/methodology/approach: The investigations included observations of the microstructure on a light microscope, researches of mechanical properties in a static tensile test, microhardness measurements made by Vickers’s method and corrosion resistance test examined using weight method. The analysis of the phase composition was carried out on the basis of X-ray researches. The amount of martensite ?’ in the obtained microstructures was investigated with ferritescope magnetic tester. The observations of the surface morphology after corrosive tests were carried out using Scanning Electron Microscope. The scope of this study was to achieve the correlations between the mechanical, corrosion and structural properties of cold rolled stainless steel.Findings: Plastic deformation in a cold working of austenitic stainless steel induced in its structure martensitic transformation ? ? ?’. The occurrence of martensite ?’ in the investigated steel structure has an essential meaning in manufacturing process of forming sheet-metals from austenitic steel.Research limitations/implications: The X-ray phase analysis in particular permitted to disclose and identify the main phases on the structure of the investigated steel after its deformation within the range 10 - 70%. The results of the ferritescope measurements allowed determining the proportional part of ?` phases in the structure of investigated steel in the examined range of cold plastic deformation. The microscope observations of the surface samples subjected to corrosion resistance test in 30 wt% H2SO4 solutions permitted to evaluate kinds and the rate of corrosion damages.Originality/value: A wide range of practical applications of 18/8 steel sheets is warranted by both their high corrosion resistance and high plastic properties.

  1. Composite microstructural anisotropies in reservoir rocks: consequences on elastic properties and relation with deformation; Anisotropies microstructurales composites dans les roches reservoir: consequences sur les proprietes elastiques et relation a la deformation

    Energy Technology Data Exchange (ETDEWEB)

    Louis, L.

    2003-10-15

    From diagenesis to tectonic stress induced deformation, rock microstructures always present some anisotropy associated with a preferential orientation, shape or spatial arrangement of its constituents. Considering the consequences anisotropy has on directional transport properties and compliance, as the geological history it carries, this approach has received a particular attention in numerous works. In this work, the microstructural features of various sedimentary rocks were investigated through direct observations and laboratory measurements in naturally deformed and undeformed blocks, samples being considered as effective media. All investigated samples were found to be anisotropic with respect to the physical properties we measured (i.e. ultrasonic P-wave velocity, magnetic susceptibility, electrical conductivity). Considering that P-wave velocities can be described by a second order tensor, we applied to the velocity data the same inversion procedure as the one routinely used in magnetic studies, which provided an efficient tool to estimate and compare these 3D anisotropies with respect to the original sample geographical position. In each case, we tried to identify as thoroughly as possible the microstructural source of the observed anisotropies, first by the mean of existing models, then through direct observations (optic and electronic microscopy). Depending on the rock investigated, anisotropy was found to be controlled by pore shape, intergranular contact distribution, preferentially oriented microcracks interacting with compaction pattern or pressure solution cleavages interacting with each other. The net result of this work is that P-wave velocity anisotropy can express the interaction between different microstructural features as well as their evolution during deformation. (author)

  2. Effect of the lattice octupole fields on the synchro-betatron mode coupling instability

    Science.gov (United States)

    Pestrikov, D. V.

    2014-02-01

    Within the framework of a simplifying model and in the first approximation of the perturbation theory we discuss the effect of the Landau damping on the synchro-betatron mode coupling instability of a single bunch in a storage ring. We assume that the required by Landau damping frequency spreads of the betatron and of the synchro-betatron modes are provided by the octupole nonlinearity of the ring lattice focusing. We also assume that the wakefields of the bunch decay substantially during the revolution period of particles along the closed orbit. For this reason, the memory of the bunch wakefields are ignored in this paper.

  3. Effect of the lattice octupole fields on the synchro-betatron mode coupling instability

    Energy Technology Data Exchange (ETDEWEB)

    Pestrikov, D.V., E-mail: pestrikov@inp.nsk.su [Budker Institute of Nuclear Physics, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, 630090 Novosibirsk (Russian Federation)

    2014-02-21

    Within the framework of a simplifying model and in the first approximation of the perturbation theory we discuss the effect of the Landau damping on the synchro-betatron mode coupling instability of a single bunch in a storage ring. We assume that the required by Landau damping frequency spreads of the betatron and of the synchro-betatron modes are provided by the octupole nonlinearity of the ring lattice focusing. We also assume that the wakefields of the bunch decay substantially during the revolution period of particles along the closed orbit. For this reason, the memory of the bunch wakefields are ignored in this paper.

  4. A novel antiproton radial diagnostic based on octupole induced ballistic loss

    CERN Document Server

    Andresen, G B; Bowe, P D; Bray, C C; Butler, E; Cesar, C L; Chapman, S; Charlton, M; Fajans, J; Fujiwara, M C; Funakoshi, R; Gill, D R; Hangst, J S; Hardy, W N; Hayano, R S; Hayden, M E; Humphries, A J; Hydomako, R; Jenkins, M J; Jørgensen, L V; Kurchaninov, L; Lambo, R; Madsen, N; Nolan, P; Olchanski, K; Olin, A; Page, R D; Povilus, A; Pusa, P; Robicheaux, F; Sarid, E; Seif El Nasr, S; Silveira, D M; Storey, J W; Thompson, R I; van der Werf, D P; Wurtele, J S; Yamazaki, Y

    2008-01-01

    We report results from a novel diagnostic that probes the outer radial profile of trapped antiproton clouds. The diagnostic allows us to determine the profile by monitoring the time-history of antiproton losses that occur as an octupole field in the antiproton confinement region is increased. We show several examples of how this diagnostic helps us to understand the radial dynamics of antiprotons in normal and nested Penning-Malmberg traps. Better understanding of these dynamics may aid current attempts to trap antihydrogen atoms.

  5. Electric transitions from octupole states in 158Dy and 168Er nuclei

    International Nuclear Information System (INIS)

    The phenomenological model is used for the study of the characteristics of low-lying states of negative parity in 158Dy and 168Er. The spectra of octupole bands and reduced probability ratios of E1-transitions are discussed. Calculated level energies and B(E1) value ratios are compared with experimental ones and also with the results of microscopic model. The results of our model show that the simple phenomenological model describes the experimental data more satisfactorily than the microscopic model. Using the phenomenological model, firstly introduced for actinides, it is possible to obtain good results for rare earth region nuclei as well

  6. A novel antiproton radial diagnostic based on octupole induced ballistic loss

    International Nuclear Information System (INIS)

    We report results from a novel diagnostic that probes the outer radial profile of trapped antiproton clouds. The diagnostic allows us to determine the profile by monitoring the time history of antiproton losses that occur as an octupole field in the antiproton confinement region is increased. We show several examples of how this diagnostic helps us to understand the radial dynamics of antiprotons in normal and nested Penning-Malmberg traps. Better understanding of these dynamics may aid current attempts to trap antihydrogen atoms

  7. Interrelation between the isoscalar octupole phonon and the proton-neutron mixed-symmetry quadrupole phonon in near spherical nuclei

    OpenAIRE

    Smirnova, Nadya A.; Pietralla, Norbert; Mizusaki, Takahiro; Isacker, Piet

    2000-01-01

    The interrelation between the octupole phonon and the low-lying proton-neutron mixed-symmetry quadrupole phonon in near-spherical nuclei is investigated. The one-phonon states decay by collective E3 and E2 transitions to the ground state and by relatively strong E1 and M1 transitions to the isoscalar 2+ state. We apply the proton-neutron version of the Interacting Boson Model including quadrupole and octupole bosons (sdf-IBM-2). Two F-spin symmetric dynamical symmetry limits...

  8. Influence of strain rate on mechanical properties and deformation texture of hot-pressed and rolled beryllium

    International Nuclear Information System (INIS)

    Plastic deformation of hexagonal metals such as beryllium occurs by a mix of dislocation slip and deformation twinning mechanisms. Slip and twinning are controlled by different mechanisms at the atomic scale, and thus respond differently to variations in strain rate. In general, deformation twinning is expected to be favored by high strain rate conditions. Both textured and randomly textured polycrystalline beryllium samples were deformed at strain rates from 0.0001/s to 5000/s. The yield point was found to be strain rate insensitive over the 7+ orders of magnitude of strain rate. The hardening, however, is strongly rate dependent for some of the initial textures, depending on loading direction relative to the basal poles. Optical microscopy and neutron diffraction measurements of the crystallographic texture were carried out to monitor the evolution of the microstructure and, specifically, the activity of deformation twinning as a function of strain rate. The relative roles of the active slip and twin deformation mechanisms are linked to the observed rate dependence of the flow stress.

  9. Beta-decay properties of neutron-rich Ge, Se, Kr, Sr, Ru, and Pd isotopes from deformed quasiparticle random-phase approximation

    CERN Document Server

    Sarriguren, P

    2015-01-01

    Beta-decay properties of even and odd-A neutron-rich Ge, Se, Kr, Sr, Ru, and Pd isotopes involved in the astrophysical rapid neutron capture process are studied within a deformed proton-neutron quasiparticle random-phase approximation. The underlying mean field is described self-consistently from deformed Skyrme Hartree-Fock calculations with pairing correlations. Residual interactions in the particle-hole and particle-particle channels are also included in the formalism. The isotopic evolution of the various nuclear equilibrium shapes and the corresponding charge radii are investigated in all the isotopic chains. The energy distributions of the Gamow-Teller strength as well as the beta-decay half-lives are discussed and compared with the available experimental information. It is shown that nuclear deformation plays a significant role in the description of the decay properties in this mass region. Reliable predictions of the strength distributions are essential to evaluate decay rates in astrophysical scenari...

  10. Effect of high-pressure torsion deformation on surface properties and biocompatibility of Ti-50.9 mol. %Ni alloys.

    Science.gov (United States)

    Awang Shri, Dayangku Noorfazidah; Tsuchiya, Koichi; Yamamoto, Akiko

    2014-06-01

    Ti-50.9 mol. %Ni was subjected to high-pressure torsion (HPT) deformation for different number of rotations (N) of 0.25, 0.5, 1, 5, and 10. The structural changes induced by HPT were analyzed using x-ray diffractometer (XRD). The surfaces of the samples before and after cell culture were characterized using x-ray photoelectron spectroscopy (XPS). The biocompatibility of the samples was evaluated based on a colony formation assay, nickel ion release, and protein adsorption behavior. XRD analysis revealed the occurrence of grain refinement, phase transformation, and amorphization in the TiNi samples by HPT deformation due to high dislocation density. The changes in chemical composition and thickness of the passive film formed on the surface observed in XPS analysis reveals improvement in the stability of the passive film by HPT deformation. The microstructural change due to the deformation was found to influence the biocompatibility behaviors of TiNi. Plating efficiency and protein adsorption were found to be higher when the samples are in stress-induced martensitic or amorphous state. HPT deformation was found to alter the surface behavior of the TiNi, which effectively reduced the Ni ion release and improved its biocompatibility. PMID:24985211

  11. The property of {kappa}-deformed statistics for a relativistic gas in an electromagnetic field: {kappa} parameter and {kappa}-distribution

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Lina [Department of Physics, School of Science, Tianjin University, Tianjin 300072 (China); Du, Jiulin [Department of Physics, School of Science, Tianjin University, Tianjin 300072 (China)]. E-mail: jiulindu@yahoo.com.cn; Liu, Zhipeng [Department of Physics, School of Science, Tianjin University, Tianjin 300072 (China)

    2007-08-06

    We investigate the physical property of the {kappa} parameter and the {kappa}-distribution in the {kappa}-deformed statistics, based on Kaniadakis entropy, for a relativistic gas in an electromagnetic field. We derive two relations for the relativistic gas in the framework of {kappa}-deformed statistics, which describe the physical situation represented by the relativistic {kappa}-distribution function, provide a reasonable connection between the parameter {kappa}, the temperature four-gradient and the four-vector potential gradient, and thus present for the case {kappa}<>0 one clearly physical meaning. It is shown that such a physical situation is a meta-equilibrium state of the system, but has a new physical characteristic.

  12. The property of kappa-deformed statistics for a relativistic gas in an electromagnetic field: kappa parameter and kappa-distribution

    CERN Document Server

    Lina, Guo; Zhipeng, Liu

    2007-01-01

    We investigate the physical property of the kappa parameter and the kappa-distribution in the kappa-deformed statistics, based on Kaniadakis entropy, for a relativistic gas in an electromagnetic field. We derive two relations for the relativistic gas in the framework of kappa-deformed statistics, which describe the physical situation represented by the relativistic kappa-distribution function, provide a reasonable connection between the parameter kappa, the temperature four-gradient and the four-vector potential gradient, and thus present for the case kappa different from zero a clearly physical meaning. It is shown that such a physical situation is a meta-equilibrium state of the system, but has a new physical characteristic.

  13. High-accuracy optical clock based on the octupole transition in 171Yb+

    CERN Document Server

    Huntemann, N; Lipphardt, B; Weyers, S; Tamm, Chr; Peik, E

    2011-01-01

    We experimentally investigate an optical frequency standard based on the 467 nm (642 THz) electric-octupole reference transition 2S1/2(F=0) -> F7/2(F=3) in a single trapped 171Yb+ ion. The extraordinary features of this transition result from the long natural lifetime and from the 4f136s2 configuration of the upper state. The electric quadrupole moment of the 2F7/2 state is measured as -0.041(5) e(a0)^2, where e is the elementary charge and a0 the Bohr radius. We also obtain information on the differential scalar and tensorial components of the static polarizability and of the probe light induced ac Stark shift of the octupole transition. With a real-time extrapolation scheme that eliminates this shift, the unperturbed transition frequency is realized with a fractional uncertainty of 7.1x10^(-17). The frequency is measured as 642 121 496 772 645.15(52) Hz with the uncertainty essentially determined by the employed caesium fountain reference.

  14. Characterization of octupole-type structures in Th221

    Science.gov (United States)

    Reviol, W.; Janssens, R. V. F.; Frauendorf, S.; Sarantites, D. G.; Carpenter, M. P.; Chen, X.; Chiara, C. J.; Hartley, D. J.; Hauschild, K.; Lauritsen, T.; Lopez-Martens, A.; Montero, M.; Pechenaya, O. L.; Seweryniak, D.; Snyder, J. B.; Zhu, S.

    2014-10-01

    A detailed level scheme for Th221 has been established in an experiment using the O18+207Pb reaction at 96 MeV. The evaporation residues from this fissile system were selected with the HERCULES detector array and residue-gated ? rays were measured with Gammasphere. Three band structures of interlinked, alternating-parity levels are observed, two of which are non-yrast. In addition, several high-lying excitations are found. The yrast band is seen up to spin-parity 37/2- and 39/2+, beyond which a high-spin feeding transition is observed. The non-yrast sequences are interpreted as parity-doublet structures, based on a configuration similar to that of the yrast band in Th223 (K=5/2). The key properties of even-odd nuclei in this mass region [B(E1)/B(E2) and B (M1)/B(E2) ratios, spin alignments, parity splittings] are reviewed.

  15. Boron nitride nanotubes reinforced aluminum composites prepared by spark plasma sintering: Microstructure, mechanical properties and deformation behavior

    International Nuclear Information System (INIS)

    Boron nitride nanotubes (BNNT) reinforced aluminum based composites are synthesized by spark plasma sintering (SPS). The concentration of BNNT is varied as 0, 2 and 5 vol% in the aluminum matrix. Micro-pillar compression testing revealed that Al–5 vol% BNNT has yield strength and compressive strength as 88 MPa and 216 MPa respectively, which is more than 50% improvement over unreinforced Al. BNNT play an active role in strengthening Al matrix through effective load bearing and transfer by crack bridging and sword in sheath mechanisms. Cold rolling of Al–5 vol% BNNT with 75% thickness reduction in a single pass exhibited high deformability without cracking or disintegration. The deformation is dominated by slip signifying ductile behavior in sintered Al with and without BNNT. BNNT survives the extreme temperature and pressure conditions during SPS processing and heavy deformation during cold rolling

  16. Boron nitride nanotubes reinforced aluminum composites prepared by spark plasma sintering: Microstructure, mechanical properties and deformation behavior

    Energy Technology Data Exchange (ETDEWEB)

    Lahiri, Debrupa; Hadjikhani, Ali; Zhang, Cheng [Plasma Forming Lab, Advanced Materials Engineering Research Institute (AMERI), Mechanical and Materials Engineering, Florida International University, Miami, FL 33174 (United States); Xing, Tan; Li, Lu Hua; Chen, Ying [Institute for Frontier Materials, Deakin University, Geelong Waurn Ponds Campus, VIC 3216 (Australia); Agarwal, Arvind, E-mail: agarwala@fiu.edu [Plasma Forming Lab, Advanced Materials Engineering Research Institute (AMERI), Mechanical and Materials Engineering, Florida International University, Miami, FL 33174 (United States)

    2013-07-01

    Boron nitride nanotubes (BNNT) reinforced aluminum based composites are synthesized by spark plasma sintering (SPS). The concentration of BNNT is varied as 0, 2 and 5 vol% in the aluminum matrix. Micro-pillar compression testing revealed that Al–5 vol% BNNT has yield strength and compressive strength as 88 MPa and 216 MPa respectively, which is more than 50% improvement over unreinforced Al. BNNT play an active role in strengthening Al matrix through effective load bearing and transfer by crack bridging and sword in sheath mechanisms. Cold rolling of Al–5 vol% BNNT with 75% thickness reduction in a single pass exhibited high deformability without cracking or disintegration. The deformation is dominated by slip signifying ductile behavior in sintered Al with and without BNNT. BNNT survives the extreme temperature and pressure conditions during SPS processing and heavy deformation during cold rolling.

  17. The influence of severe plastic deformation by high pressure torsion on structure and mechanical properties of Hadfield steel single crystals

    International Nuclear Information System (INIS)

    Hadfield steel single crystals have been deformed by high pressure torsion at room temperature (P=5GPa) for 1, 2, 3 revolutions. The resulting microstructure has been studied by means of transmission electron microscopy (TEM) and X-ray analysis. The size of fragments decreases with increasing number of revolutions due to interaction of slip dislocations, microbands and thin twins. As a result of severe plastic deformation, the microhardness of the Hadfield steel has been increased, and a portion of ?, ?' martensite has been found.

  18. The influence of severe plastic deformation by high pressure torsion on structure and mechanical properties of Hadfield steel single crystals

    Science.gov (United States)

    Zakharova, G. G.; Astafurova, E. G.

    2010-07-01

    Hadfield steel single crystals have been deformed by high pressure torsion at room temperature (P=5GPa) for 1, 2, 3 revolutions. The resulting microstructure has been studied by means of transmission electron microscopy (TEM) and X-ray analysis. The size of fragments decreases with increasing number of revolutions due to interaction of slip dislocations, microbands and thin twins. As a result of severe plastic deformation, the microhardness of the Hadfield steel has been increased, and a portion of epsilon, ?' martensite has been found.

  19. The influence of severe plastic deformation by high pressure torsion on structure and mechanical properties of Hadfield steel single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Zakharova, G G; Astafurova, E G, E-mail: galinazg@yandex.r [Institute of Strength Physics and Materials Science, Siberian Branch of Russian Academy of Sciences, Akademichesky prospect 2/4, 634021, Tomsk (Russian Federation)

    2010-07-01

    Hadfield steel single crystals have been deformed by high pressure torsion at room temperature (P=5GPa) for 1, 2, 3 revolutions. The resulting microstructure has been studied by means of transmission electron microscopy (TEM) and X-ray analysis. The size of fragments decreases with increasing number of revolutions due to interaction of slip dislocations, microbands and thin twins. As a result of severe plastic deformation, the microhardness of the Hadfield steel has been increased, and a portion of {epsilon}, {alpha}' martensite has been found.

  20. Effect of Radial and Axial Deformation on Electron Transport Properties in a Semiconducting Si-C Nanotube

    Directory of Open Access Journals (Sweden)

    S. Choudhary

    2011-01-01

    Full Text Available We study the bias voltage dependent current characteristic in a deformed (8, 0 silicon carbide nanotube by applying self consistent non-equilibrium Green’s function formalism in combination with the density-functional theory to a two probe molecular junction constructed from deformed nanotube. The transmission spectra and electron density of states at zero bias shows a significant reduction in threshold in the case of both radially compressed and axially elongated nanotube. However, semiconductor to metal transition was not observed, though the results show large differences in current characteristic compared to a perfect nanotube.

  1. Mechanical properties of Fe -10Ni -7Mn martensitic steel subjected to severe plastic deformation via cold rolling and wire drawing

    Energy Technology Data Exchange (ETDEWEB)

    Ghasemi-Nanesa, H; Shirazi, H [School of Metallurgy and Materials Engineering, Faculty of Engineering, University of Tehran, P.O. Box 14395-731 (Iran, Islamic Republic of); Nili-Ahmadabadi, M, E-mail: sut.caster.81710018@gmail.co, E-mail: nili@ut.ac.i [School of Metallurgy and Materials Engineering, Faculty of Engineering, University of Tehran, P.O. Box 14395-731 (Iran, Islamic Republic of) and Center of Excellence for High Performance Materials, University of Tehran, P.O. Box 14395-731, Tehran (Iran, Islamic Republic of)

    2010-07-01

    Fe-Ni-Mn martensitic steels are one of the major groups of ultra-high strength steels that have good mechanical properties and ductility in as annealed condition but they suffer from severe inter-granular embitterment after aging. In this paper, the effect of heavy shaped cold rolling and wire drawing on the mechanical properties of Fe-Ni-Mn steel was investigated. This process could provide a large strain deformation in this alloy. The total strain was {epsilon} {approx}7. Aging behavior and tensile properties of Fe-10Ni-7Mn were studied after aging at 753 K. The results showed that the ultimate tensile strength and ductility after cold rolling, wire drawing and aging increased up to 2540 MPa and 7.1 %, respectively, while the conventional steels show a premature fracture stress of 830 MPa with about zero ductility after aging.

  2. Correlation of plastic deformation induced intermittent electromagnetic radiation characteristics with mechanical properties of Cu-Ni alloys

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Ranjana; Lal, Shree P. [Birla Institute of Technology, Patna (India); Misra, Ashok [RTC Institute of Technology, Ranchi (India)

    2015-02-15

    This paper presents experimental results on intermittent electromagnetic radiation during plastic deformation of Cu-Ni alloys under tension and compression modes of deformation. On the basis of the nature of electromagnetic radiation signals, oscillatory or exponential, results show that the compression increases the viscous coefficient of Cu-Ni alloys during plastic deformation. Increasing the percentage of solute atoms in Cu-Ni alloys makes electromagnetic radiation strength higher under tension. The electromagnetic radiation emission occurs at smaller strains under compression showing early onset of plastic deformation. This is attributed to the role of high core region tensile residual stresses in the rolled Cu-Ni alloy specimens in accordance with the Bauschinger effect. The distance between the apexes of the dead metal cones during compression plays a significant role in electromagnetic radiation parameters. The dissociation of edge dislocations into partials and increase in internal stresses with increase in solute percentage in Cu-Ni alloys under compression considerably influences the electromagnetic radiation frequency.

  3. Correlation of plastic deformation induced intermittent electromagnetic radiation characteristics with mechanical properties of Cu-Ni alloys

    International Nuclear Information System (INIS)

    This paper presents experimental results on intermittent electromagnetic radiation during plastic deformation of Cu-Ni alloys under tension and compression modes of deformation. On the basis of the nature of electromagnetic radiation signals, oscillatory or exponential, results show that the compression increases the viscous coefficient of Cu-Ni alloys during plastic deformation. Increasing the percentage of solute atoms in Cu-Ni alloys makes electromagnetic radiation strength higher under tension. The electromagnetic radiation emission occurs at smaller strains under compression showing early onset of plastic deformation. This is attributed to the role of high core region tensile residual stresses in the rolled Cu-Ni alloy specimens in accordance with the Bauschinger effect. The distance between the apexes of the dead metal cones during compression plays a significant role in electromagnetic radiation parameters. The dissociation of edge dislocations into partials and increase in internal stresses with increase in solute percentage in Cu-Ni alloys under compression considerably influences the electromagnetic radiation frequency.

  4. Deformation potentials in AlGaN and InGaN alloys and their impact on optical polarization properties of nitride quantum wells

    DEFF Research Database (Denmark)

    ?epkowski, S. P.; Gorczyca, I.

    2013-01-01

    The deformation potentials acz?D1, act?D2, D3, D4, and D5 are determined for random AlGaN and InGaN alloys using electronic band structure calculations based on the density functional theory. A sublinear composition dependence is obtained for acz?D1 and D3 in AlGaN, and D3 in InGaN, whereas superlinear behavior on composition is found foract?D2, D4, and D5 in AlGaN, and act?D2and D5 in InGaN. The optical polarization properties of nitride quantum wells are very well described by the k·p method when the obtained deformation potentials are included. In m-plane AlGaN/AlN and InGaN/GaN quantum wells, the difference between the interband transition energies for light polarized parallel and orthogonal to the crystalline c axis compares more favorably to experimental data, than when deformation potentials previously reported in literature are used.

  5. Determination of deformation and failure properties of ductile materials by means of the Small Punch Test; Bestimmung von Verformungs- und Versagenseigenschaften duktiler Werkstoffe aus dem Small Punch Test

    Energy Technology Data Exchange (ETDEWEB)

    Lauschke, U.; Kuna, M. [TU Bergakademie Freiberg (Germany). Inst. fuer Mechanik und Maschinenelemente

    2000-07-01

    The materials behavior in structural components is changing due to in-service loading, aging, embrittlement a. o., which requires an in situ surveillance of the materials state. In order to minimize the amount of repair costs and of damage of the component, the size of the material taken out for a test specimen should be very small but representative. In the small punch test (SPT), a disc-like specimen of 8 x 0,5 mm size is deformed in a miniaturized deep-drawing experiment. The measurable output is the load-displacement-curve of the punch, which contains information about the elastoplastic deformation behavior and about the strength properties of the material. A new SPT-testing device is constructed and optimized with respect to geometry, loading and experimental realization. A nonlinear optimization algorithm is elaborated to identify the parameters of the true stress-strain-curve from the test results and from finite element simulations. The specimens fail by plastic necking and subsequent crack formation. This softening part of the load-displacement-curve caused by local failure behavior is modeled by the continuum damage theory of Gurson-Tvergaard-Needleman. Finally, first examples on ferrite steels show the capability of the SPT to characterize the deformation and failure behavior of ductile materials. (orig.)

  6. Deformation mechanisms, architecture, and petrophysical properties of large normal faults in platform carbonates and their role in the release of carbon dioxide from earth's interior in central Italy

    Science.gov (United States)

    Agosta, Fabrizio

    2006-04-01

    A challenging theme of research in structural geology is the process of faulting in carbonate rocks: how do the resulting internal architecture and petrophysical properties of faults affect subsurface fluid flow. A better understanding of this process is important to evaluate the potential oil and gas recovery from carbonate reservoirs, and to plan CO 2 containment in the depleted reservoirs. Carbonate rocks may deform with different mechanisms depending primarily on their original sedimentary fabric, diagenetic history, fluid content, and tectonic environment. In this dissertation I investigate the deformation mechanisms, petrophysics, and internal fluid composition of large, seismic, basin-bounding normal faults in low porosity platform carbonates. Based on the nature, orientation, and abutting relationships of the structural elements preserved within the faults and in the surrounding carbonate host rocks, I was able to characterize the mechanisms of fault growth and the fault architecture. Incipient faulting occurred at shallow depths by sequential formation and shearing of pressure solution seams and joints/veins; with ongoing deformation and exhumation, the joint-based mechanism became predominant. The end result is a mature normal fault that juxtaposes basin sedimentary rocks of the hanging wall against deformed carbonates of the footwall. The deformed carbonates of the fault footwalls are composed of rocks with low porosity and permeability and major slip surfaces in the fault core, and fragmented carbonate matrices with high porosity and permeability, and small faults in the damage zone. The degree of fragmentation in the damage zone generally increases towards the fault hanging wall, forming structural domains characterized by different deformation intensity. The rocks of the fault core have sub-spherical pores, those of the damage zone have elongated, crack-like, pores. The permeability structure of the normal fault zones is therefore made up of a fault core that acts as a barrier to fluid flow, and fragmented carbonates that enhance fluid flow. Stable isotope geochemistry data shows two main sources of the fluids that precipitated minerals within the normal faults. The main fluid source is infiltrated meteoric water, the second is CO2-enriched groundwater. Both fluids compartmentalized primarily along the major slip surfaces of the fault cores.

  7. q-Deformed Dynamics and Virial Theorem

    OpenAIRE

    Zhang, Jian-zu

    2002-01-01

    In the framework of the q-deformed Heisenberg algebra the investigation of $q$-deformation of Virial theorem explores that q-deformed quantum mechanics possesses better dynamical property. It is clarified that in the case of the zero potential the theoretical framework for the q-deformed Virial theorem is self-consistent. In the selfadjoint states the q-deformed uncertainty relation essentially deviates from the Heisenberg one.

  8. Is nucleon deformed?

    International Nuclear Information System (INIS)

    The surprising answer to this question Is nucleon deformed? is : Yes. The evidence comes from a study of the quark model of the single nucleon and when it is found in a nucleus. It turns out that many of the long standing problems of the Naive Quark Model are taken care of if the nucleon is assumed to be deformed. Only one value of the parameter PD ?1/4 (which specifies deformation) fits gA (the axial vector coupling constant) for all the semileptonic decay of baryons, the F/D ratio, the pion-nucleon-delta coupling constant fsub(?N?), the double delta coupling constant1 fsub(???), the Ml transition moment ??N and g1p the spin structure function of proton2. All this gives strong hint that both neutron and proton are deformed. It is important to look for further signatures of this deformation. When this deformed nucleon finds itself in a nuclear medium its deformation decreases. So much that in a heavy nucleus the nucleons are actually spherical. We look into the Gamow-Teller strengths, magnetic moments and magnetic transition strengths in nuclei to study this property. (author). 15 refs

  9. Deformation and properties of ribbons of amorphous FeCo80-xSi15Bx alloys

    International Nuclear Information System (INIS)

    Change in morphology of shear bands, propagation of micro- and macrocracks, structure as well as coercive force Hc of rolled strips of Fe5Co80-xSi15Bx amorphous alloys, is studied, where x has the following values: 8.2; 10; 11.8 at.%. The found essential (more than 200 times) increase of Hc after deformation is explained by appearance of internal stresses, microcracks and nuclei of crystal phase

  10. Octupole Magnet For Soft X Ray Magnetic Dichroism Experiments: Design and Performance

    Science.gov (United States)

    Arenholz, Elke; Prestemon, Soren O.

    2004-05-01

    An octupole magnet endstation for soft x ray magnetic dichroism measurements has been developed at the Advanced Light Source. The system consists of an eight pole electromagnet that surrounds a small vacuum chamber. The magnet provides fields up to 0.9 T that can be applied in any direction relative to the incoming x ray beam. High precision magnetic circular and linear dichroism spectra can be obtained reversing the magnetic field for each photon energy in an energy scan. Moreover, the field dependence of all components of the magnetization vector can be studied in detail by choosing various angles of x ray incidence while keeping the relative orientation of magnetic field and sample fixed.

  11. Octupole magnet for soft X ray magnetic dichroism experiments: Design and performance

    International Nuclear Information System (INIS)

    An octupole magnet endstation for soft x-ray magnetic dichroism measurements has been developed at the Advanced Light Source. The system consists of an eight pole electromagnet that surrounds a small vacuum chamber. The magnet provides fields up to 0.9 T that can be applied in any direction relative to the incoming x-ray beam. High precision magnetic circular and linear dichroism spectra can be obtained reversing the magnetic field for each photon energy in an energy scan. Moreover, the field dependence of all components of the magnetization vector can be studied in detail by choosing various angles of x-ray incidence while keeping the relative orientation of magnetic field and sample fixed

  12. Octupole Magnet For Soft X Ray Magnetic Dichroism Experiments: Design and Performance

    International Nuclear Information System (INIS)

    An octupole magnet endstation for soft x ray magnetic dichroism measurements has been developed at the Advanced Light Source. The system consists of an eight pole electromagnet that surrounds a small vacuum chamber. The magnet provides fields up to 0.9 T that can be applied in any direction relative to the incoming x ray beam. High precision magnetic circular and linear dichroism spectra can be obtained reversing the magnetic field for each photon energy in an energy scan. Moreover, the field dependence of all components of the magnetization vector can be studied in detail by choosing various angles of x ray incidence while keeping the relative orientation of magnetic field and sample fixed

  13. Gyromagnetic ratios and octupole collectivity in the structure of the 90-96Zr isotopes

    International Nuclear Information System (INIS)

    Shell model calculations have been performed for low-excitation states in the Zr isotopes between 90Zr and 96Zr with an emphasis on the g factors and electromagnetic decay rates for the lowest 2+ and 3- states. Overall the 2+ states are reasonably well described. In contrast, the 3- states present a puzzle because the measured g factors imply a single-particle configuration whereas the experimental E3 transition rates imply collective structures that cannot be explained by shell model calculations. A consistent description of the 3- states in 90Zr and 96Zr is sought in terms of coupling between the single-particle structure and a collective octupole vibration

  14. Structure and dynamics of ion clusters in linear octupole traps: Phase diagrams, chirality, and melting mechanisms

    International Nuclear Information System (INIS)

    The stable structures and melting dynamics of clusters of identical ions bound by linear octupole radiofrequency traps are theoretically investigated by global optimization methods and molecular dynamics simulations. By varying the cluster sizes in the range of 10-1000 ions and the extent of trap anisotropy by more than one order of magnitude, we find a broad variety of stable structures based on multiple rings at small sizes evolving into tubular geometries at large sizes. The binding energy of these clusters is well represented by two contributions arising from isotropic linear and octupolar traps. The structures generally exhibit strong size effects, and chiral arrangements spontaneously emerge in many crystals. Sufficiently large clusters form nested, coaxial tubes with different thermal stabilities. As in isotropic octupolar clusters, the inner tubes melt at temperatures that are lower than the overall melting point.

  15. Entrance-channel effects in heavy-ion capture: role of octupole phonons

    International Nuclear Information System (INIS)

    The introduction of the 'experimental barrier distribution'd2(E?fus)/dE2 gave a simple means of highlighting the dynamics of heavy-ion fusion reactions, as well as giving a demanding test of the quality of theoretical calculations. However, in many cases where data have been taken at deep sub-barrier energies, understanding the distribution is not sufficient. Here, the logarithmic derivative d[ln(E?fus)]/dE provides a very useful additional test. It is suggested that high-lying octupole phonon states, long thought simply to give a global shift of the distribution downward in energy, may play a more complex role in the reaction dynamics, contributing much to the underlying physics of both the above functions.

  16. Optical and wetting properties of nanostructured fluorinated ethylene propylene changed by mechanical deformation and its application in triboelectric nanogenerators

    Science.gov (United States)

    Guo, Xiaodong; Helseth, Lars Egil

    2015-01-01

    We demonstrate that nanostructured fluorinated ethylene propylene (FEP) polymer films undergo a non-reversible structural transition when exposed to an applied force. While reactive ion etching (RIE) treatment creates FEP films with well-defined nanostructures, applied stress causes a permanent deformation which alters the optical reflectance spectrum. The structural changes of the FEP films also altered the contact angles of water droplets. It was found that the contact angles changed from 109° before to 139° after RIE treatment, and plastic deformation reduced the contact angles to 111°. Scanning electron microscopy images revealed freshly formed homogeneous surfaces, with nanostructures hidden below, which correlated with the macroscopic changes in optical reflectance. Interestingly, the contact electrification between FEP and aluminum did not change when the nanostructures were deformed, and we propose that the nanostructured FEP surface can be used to both optically monitor the state of the nanostructure as well as functioning as a part of an energy harvesting system. At an average power of about 22 ?W with an area of 4 cm2, the energy harvester is able to light up a large number of light emitting diodes.

  17. Deformed Calabi-Yau Completions

    OpenAIRE

    Keller, Bernhard

    2009-01-01

    We define and investigate deformed n-Calabi-Yau completions of homologically smooth differential graded (=dg) categories. Important examples are: deformed preprojective algebras of connected non Dynkin quivers, Ginzburg dg algebras associated to quivers with potentials and dg categories associated to the category of coherent sheaves on the canonical bundle of a smooth variety. We show that deformed Calabi-Yau completions do have the Calabi-Yau property and that their constru...

  18. Enhancement of nuclear Schiff moments and time reversal violation in atoms due to combination of soft nuclear octupole and quadrupole vibrations

    OpenAIRE

    Lisetskiy, A. F.; Flambaum, V. V.; Zelevinsky, V. G.

    2005-01-01

    Nuclear forces violating parity and time reversal invariance P,T-odd produce P,T-odd nuclear moments, for example, the nuclear Schiff moment. In turn, this moment can induce the electric dipole moment (EDM) in the atom. The contribution to the Schiff moment from the soft collective quadrupole and octupole vibrations in spherical nuclei is calculated in the framework of the quasiparticle random phase approximation with separable quadrupole and octupole forces. The values of n...

  19. Mechanical properties and peculiar features of energy dissipation of ultrafine-grained aluminum alloys under dynamic deformation

    Science.gov (United States)

    Petrova, A.; Brodova, I.; Shorokhov, E.; Plekhov, O.; Naimark, O.

    2014-08-01

    This paper presents experimental results on the thermodynamics of deformation process and mechanical behavior of the ultrafine grained aluminum alloys under dynamic compression. Dynamic compression tests were performed on a Hopkinson-Kolsky split bar at the strain rate of 103 s'1 with simultaneously recording the surface temperature of samples by an infrared camera. Energy dissipation ability was determined for ultrafine-grained alloys. An inverse strain rate dependency of dynamic yield strength was observed in the ultrafine-grained Al-Zn-Mg-Cu alloy (A7075).

  20. Strong M1 components in 3-i?3-1 in nearly spherical nuclei: Evidence for isovector-octupole excitations

    International Nuclear Information System (INIS)

    An evaluation of data obtained in (n,n'?) experiments reveals strong M1 3-i ? 3-1 transitions in nuclei near the N=50 (92Zr, 94Mo and 96Mo), Z=50 (112Cd and 114Cd) and N=82 (144Nd) shell closures. The observed left angle 31- M1 3i- right angle matrix elements scale with the left angle 21+ parallel M1 parallel 2+ms right angle matrix elements, and the energy difference between the initial 3-i state and the 3-1 octupole phonon is proportional to the left angle 3-1 parallel E3 parallel 0+gs right angle matrix element. The possibility of assigning the states of interest as octupole mixed-symmetry states is discussed.

  1. Strong M1 components in 3i-?31- transitions in nearly spherical nuclei: Evidence for isovector-octupole excitations

    International Nuclear Information System (INIS)

    An evaluation of data obtained in (n,n'?) experiments reveals strong M1 3i-?31- transitions in nuclei near the N=50 (92Zr, 94Mo, and 96Mo), Z=50 (112Cd and 114Cd), and N=82 (144Nd) shell closures. The observed 1-||M1||3i-> matrix elements scale with the 1+||M1||2ms+> matrix elements connecting the mixed-symmetric and symmetric quadrupole excitations. In accordance with a picture of a mixed two-component quantum system, the energy difference between the initial 3i- state and the 31- octupole phonon is proportional to the |1-||E3||0gs+>| matrix element. The possibility of assigning the 3- states of interest as octupole isovector states is discussed.

  2. Nuclear alternating-parity bands and transition rates in a model of coherent quadrupole–octupole motion

    International Nuclear Information System (INIS)

    A further extension of a model of coherent quadrupole–octupole vibrations and rotations and its application to alternating-parity spectra in heavy even–even nuclei is presented. Within the model the yrast alternating-parity sequence includes the ground state band and the lowest negative parity levels with odd angular momenta, while the non-yrast sequences include excited ?-bands and higher negative-parity levels. Electric transition operators reflecting the complex shape characteristics associated with the quadrupole–octupole vibration modes are introduced. By using them B(E1), B(E2) and B(E3) reduced transition probabilities within and between the different energy sequences are calculated. It is shown that the model successfully reproduces yrast and non-yrast alternating-parity bands together with the attendant B(E1)–B(E3) transition rates in the nuclei 154Sm, 156Gd and 100Mo. (author)

  3. Microstructure and property evolution of isotropic and anisotropic NdFeB magnets fabricated from nanocrystalline ribbons by spark plasma sintering and hot deformation

    International Nuclear Information System (INIS)

    Isotropic and anisotropic NdFeB magnets were synthesized by spark plasma sintering (SPS) and SPS+HD (hot deformation), respectively, using melt-spun ribbons as the starting materials. Spark plasma sintered magnets sintered at low temperatures (0C) almost maintained the uniform fine grain structure inherited from rapid quenching. At higher temperatures, due to the local high-temperature field caused by the spark plasma discharge, the grain growth occurred at the initial particle surfaces and the coarse grain zones formed in the vicinity of the particle boundaries. Since the interior of the particles maintained the fine grain structure, a distinct two-zone structure was formed in the spark plasma sintered magnets. The SPS temperature and pressure have important effects on the widths of coarse and fine grain zones, as well as the grain sizes in two zones. The changes in grain structure led to variations in the magnetic properties. By employing low SPS temperature and high pressure, high-density magnets with negligible coarse grain zone and an excellent combination of magnetic properties can be obtained. An anisotropic magnet with a maximum energy product of ?30 MG Oe was produced by the SPS+HD process. HD at 750 0C did not lead to obvious grain growth and the two-zone structure still existed in the hot deformed magnets. Intergranular exchange coupling was demonstrated in the spark plasma sintered magnets and was enhanced by the HD process, whs and was enhanced by the HD process, which reduced the coercivity. Good temperature stability was manifested by low temperature coefficients of remanence and coercivity. The results indicated that nanocrystalline NdFeB magnets without significant grain growth and with excellent properties could be obtained by SPS and HD processes.

  4. Confinement properties of high energy density plasmas in the Wisconsin levitated octupole

    International Nuclear Information System (INIS)

    The confinement of particles and energy is critically dependent on the plasma-wall interaction. Results of a study detailing this interaction are presented. High power ICRF heated and gun afterglow plasmas were studied to detail the mechanisms determining particle and energy confinement. An extensive zero-D simulation code is used to assist in interpreting the experimental data. Physically reasonable models for plasma surface interactions, time dependent coronal treatment of impurities and multiple region treatment of neutrals are used in modeling the plasma. Extensive diagnostic data are used to verify the model. Non-heated plasmas decay from 28 to 3 eV allowing clear identification of wall impact energy thresholds for desorption and particle reflection. The charge state distribution of impurities verifies the reflux to plasma diffusion rate ratio. Close agreement between the simulation and experimental data is found

  5. Study of large-scale mechanical properties and deformation by modeling of the La Clapière landslide by a numerical modeling approach (Saint-Etienne de Tinée, France).

    Science.gov (United States)

    Tric, E.; Bouissou, S.; Lebourg, T.; Jomard, H.; Guglielmi, Y.

    2003-04-01

    "La Clapière" Landslide is a large unstable slope located in the South-eastern part of France, in the Alps, about 80 km North of Nice city. Like many other deep-seated slope deformations, an interdisciplinary approach based on observations and measurements has been done on this landslide since 1970. A monitoring of the site is working since 1982 (Follaci, 1987, 1988 1999; Guglielmi et al., 2001, 2002; Merrien-Soukatchoff et al., 2001). Several conceptual scenarii of the rupture initiation and the evolution of the slope have been proposed (Follaci, 1987,1999). However, these different observational analysis have not the potential to describe the processes involved on the generation and development of a creeping rock mass out of an originally compact rock . A promising approach to reach this goal is the geomechanical modelling of the structures and properties of the creeping or sliding mass. To our knowledge, only two modelling study have been done on "La Clapière" landslide (Merrien-Soukatchoff et al., 2001; Gunzburger et al., 2002). These authors have tested, with the code UDEC, the mechanism of gravitational toppling and the influence of the deglaciation on the initiation of the instability. The purpose of this abstract is to relate the work we are undertaking on the Clapière landslide through two-dimensional finite element modelling (ADELI) (Hassani, 1994; Hassani et al., 1997). A Drucker-Prager elastoplastic behaviour is used in the model that is subject only to the gravity. We tested different geomechanical parameters (Cohesion, angle of internal friction) in order to (1) determine the critical value of these parameters from which the destabilisation is possible, (2) localise zones of plastic deformation and its temporal and spatial evolutions. We obtain a critical value of cohesion and angle of internal friction respectively in the range ]2.02 MPa; 1,99 MPa] and ]27,84^o ;27,55^o]. These values are compatible with the geomechanical parameters proposed by Gunzburger (2001) from measurements directly done on the site. We observe also a good agreement between the calculated deformation and the actual morphology of the site. Furthermore, the temporal evolution of the deformation show a maximum localised at a depth between 80 and 130 m which is also in good agreement with geophysical data obtained by electrical method which suggest the presence of sliding surface at this depth.

  6. Deformed logarithms and entropies

    CERN Document Server

    Kaniadakis, G; Scarfone, A M

    2004-01-01

    By solving a differential-functional equation inposed by the MaxEnt principle we obtain a class of two-parameter deformed logarithms and construct the corresponding two-parameter generalized trace-form entropies. Generalized distributions follow from these generalized entropies in the same fashion as the Gaussian distribution follows from the Shannon entropy, which is a special limiting case of the family. We determine the region of parameters where the deformed logarithm conserves the most important properties of the logarithm, and show that important existing generalizations of the entropy are included as special cases in this two-parameter class.

  7. Structural defects in Fe–Pd-based ferromagnetic shape memory alloys: tuning transformation properties by ion irradiation and severe plastic deformation

    International Nuclear Information System (INIS)

    Fe–Pd-based ferromagnetic shape memory alloys constitute an exciting class of magnetically switchable smart materials that reveal excellent mechanical properties and biocompatibility. However, their application is severely hampered by a lack of understanding of the physics at the atomic scale. A many-body potential is presented that matched ab inito calculations and can account for the energetics of martensite ? austenite transition along the Bain path and relative phase stabilities in the ordered and disordered phases of Fe–Pd. Employed in massively parallel classical molecular dynamics simulations, the impact of order/disorder, point defects and severe plastic deformation in the presence of single- and polycrystalline microstructures are explored as a function of temperature. The model predictions are in agreement with experiments on phase changes induced by ion irradiation, cold rolling and hammering, which are also presented. (paper)

  8. An investigation to the effect of deformation-heat treatment cycle on the eutectic morphology and mechanical properties of a Thixocast A356 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Haghshenas, M., E-mail: mhaghshe@uwo.ca [School of Metallurgical and Materials Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Zarei-Hanzaki, A. [School of Metallurgical and Materials Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Jahazi, M. [Aerospace Manufacturing Technology Centre, Institute for Aerospace Research, National Research Council Canada, 5145 Decelles Avenue, Montreal, Quebec, H3T 2B2 (Canada)

    2009-08-15

    The influences of deformation, heat treatment temperature and holding time on morphology and size distribution of Si containing eutectic phases of Thixocast Al-7Si-0.4 Mg alloy were investigated. The novel thermo-mechanical treatment consisted of initial cold working practice followed by a solution heat treatment at 540 deg. C for durations ranging from 2 min to 120 min followed by water quenching. Optical and scanning electron microscopes were used to study the influence of process parameters on microstructure evolution. Also, final mechanical properties were investigated using hardness test. The results indicate that, under appropriate conditions it is possible to achieve an ultrafine grain microstructure with the eutectic Si fibers fragmented and spheroidized in the entire microstructure. It was also found that, an agglomeration of sphrodized particles occurs and is governed by Ostwald ripening mechanism.

  9. An investigation to the effect of deformation-heat treatment cycle on the eutectic morphology and mechanical properties of a Thixocast A356 alloy

    International Nuclear Information System (INIS)

    The influences of deformation, heat treatment temperature and holding time on morphology and size distribution of Si containing eutectic phases of Thixocast Al-7Si-0.4 Mg alloy were investigated. The novel thermo-mechanical treatment consisted of initial cold working practice followed by a solution heat treatment at 540 deg. C for durations ranging from 2 min to 120 min followed by water quenching. Optical and scanning electron microscopes were used to study the influence of process parameters on microstructure evolution. Also, final mechanical properties were investigated using hardness test. The results indicate that, under appropriate conditions it is possible to achieve an ultrafine grain microstructure with the eutectic Si fibers fragmented and spheroidized in the entire microstructure. It was also found that, an agglomeration of sphrodized particles occurs and is governed by Ostwald ripening mechanism.

  10. Effects of core polarization and pairing correlations on some ground-state properties of deformed odd-mass nuclei within the higher Tamm–Dancoff approach

    International Nuclear Information System (INIS)

    In self-consistent mean-field approaches, the description of odd-mass nuclei requires to break the time-reversal invariance of the underlying one-body hamiltonian. This induces a polarization of the even-even core to which the odd nucleon is added. To properly describe the pairing correlations (in T = 1 and T = 0 channels) in such nuclei, we implement the particle-number conserving Higher Tamm–Dancoff approximation with a residual ? interaction in each isospin channel by restricting the many-body basis to two-particle–two–hole excitations of pair type (nn, pp and np) on top of the Hartree–Fock solution. We apply this approach to the calculation of two ground-state properties of well-deformed nuclei |Tz| = 1 nuclei around 24Mg and 48Cr, namely the isovector odd-even binding-energy difference and the magnetic dipole moment, focusing on the impact of pairing correlations. (author)

  11. Tuning the electronic properties of boron nitride nanotube by mechanical uni-axial deformation: a DFT study

    OpenAIRE

    Ju Shin-Pon; Wang Yao-Chun; Lien Ting-Wei

    2011-01-01

    Abstract The effect of uni-axial strain on the electronic properties of (8,0) zigzag and (5,5) armchair boron nitride nanotubes (BNNT) is addressed by density functional theory calculation. The stress-strain profiles indicate that these two BNNTS of differing types display very similar mechanical properties, but there are variations in HOMO-LUMO gaps at different strains, indicating that the electronic properties of BNNTs not only depend on uni-axial strain, but on BNNT type. The variations i...

  12. Measuring the Nuclear Magnetic Octupole Moment of a Single Trapped Barium-137 Ion

    Science.gov (United States)

    Kleczewski, Adam; Fortson, Norval; Blinov, Boris

    2009-05-01

    Recent measurements of hyperfine structure in the cesium-133 atom resolved a nuclear magnetic octupole moment ? much larger than expected from the nuclear shell model[1]. To explore this issue further, we are undertaking an experiment to measure the hyperfine structure in the 5D manifold of a single trapped barium-137 ion which, together with reliable calculations in alkali-like Ba^+, should resolve ? with sensitivity better than the shell model value [2]. We use a TmHo:YLF laser tuned to 2051 nm and a fiber laser tuned to 1762 nm to drive the 6S1/2 to 5D3/2 and 6S1/2 to 5D5/2 electric quadrupole transitions. These lasers allow us to selectively populate any hyperfine sub-level in the 5D manifold. We will then perform RF spectroscopy on the 5D states to make a precision measurement of the hyperfine frequency intervals. We report on the development of the laser and RF spectroscopy systems. [1] V. Gerginov, A. Derevianko, and C. E. Tanner, Phys. Rev. Lett. 91, 072501 [2] K. Beloy, A. Derevianko, V. A. Dzuba, G. T. Howell, B. B. Blinov, E. N. Fortson, arXiv:0804.4317v1 [physics.atom-ph] 28 Apr 2008

  13. Search for the two-phonon octupole vibrational state in {sup 208}Pb

    Energy Technology Data Exchange (ETDEWEB)

    Moore, E.F. [North Carolina State Univ., Raleigh, NC (United States)]|[Triangle Universities Nuclear Lab., Durham, NC (United States); Henning, W. [Argonne National Lab., IL (United States); Janssens, R.V.F. [Argonne National Lab., IL (United States); Khoo, T.L. [Argonne National Lab., IL (United States); Sanders, S.J. [Kansas Univ., Lawrence, KS (United States); Ahmad, I. [Argonne National Lab., IL (United States); Amro, H. [North Carolina State Univ., Raleigh, NC (United States)]|[Triangle Universities Nuclear Lab., Durham, NC (United States); Blumenthal, D. [Argonne National Lab., IL (United States); Carpenter, M.P. [Argonne National Lab., IL (United States); Crowell, B. [Argonne National Lab., IL (United States); Drigert, M.W. [Idaho National Engineering Lab., Idaho Falls (United States); Gassman, D. [Argonne National Lab., IL (United States); Henry, R.G. [Argonne National Lab., IL (United States); Lauritsen, T. [Argonne National Lab., IL (United States); Lister, C.J. [Argonne National Lab., IL (United States); Nisius, D. [Argonne National Lab., IL (United States)]|[Purdue Univ., Lafayette, IN (United States)

    1995-05-01

    We have performed an experiment to search for the two-phonon octupole vibrational state in {sup 208}Pb. Thick targets of {sup 208}Pb, {sup 209}Bi, {sup 58,64}Ni, and {sup 160}Gd were bombarded with 1305 MeV beams of {sup 208}Pb supplied by the ATLAS accelerator facility at Argonne. Gamma rays were measured using the Argonne-Notre Dame BGO gamma ray facility, consisting of 12 Compton suppressed Ge detectors surrounding an array of 50 BGO scintillators. We have identified some 30 known {gamma} rays from {sup 208}Pb in coincidence spectra gated on low-lying transitions in {sup 208}Pb. In addition, after unfolding these spectra for Compton response, we observe broad coincident structures in the energy region expected for the decay of 2-phonon states. Furthermore, we have confirmed the placement of a previously observed 2485 keV {gamma} ray in {sup 207}Pb and find no evidence consistent with the placement of this line in {sup 208}Pb. (orig.).

  14. Ion heating at the cyclotron resonance in plasmas magnetically confined in a toroidal octupole field

    International Nuclear Information System (INIS)

    Ion temperatures as high as 600 eV have been produced using rf wave heating at the ion cyclotron resonance frequency in a toroidal octupole magnetic field. Rf is coupled to the plasma with an externally driven ''fifth'' hoop which forms the inductive leg of an oscillator tank circuit. Power levels up to 1 MW at 1 to 3 MHz have been applied for periods up to 2 msec. Plasmas produced either by ECRH or by gun injection are simulated with a computer program in which known particle and energy production and loss mechanisms are used to predict the spatially averaged time behaviour of the plasma in the presence of the applied ion heating. The program can be used to calculate the consequences of the heating model in the presence of many cooling mechanisms which may each have a separate dependence on instantaneous plasma parameters. Experimental quantities compared to computer predictions include density, ion temperature, and loading of the hoop by the plasma, both resistive and reactive, and neutral reflux from the wall by electron and ion impact. Wave penetration to the resonance zone is good up to the highest densities available (6 x 1012 cm-3 by gun injection) in good agreement with theory. Neutral reflux from the walls and the large charge exchange cooling which results is the dominant loss mechanism at the higher hoop voltages

  15. Core breaking and octupole low-spin states in $^{207}$ Tl

    CERN Multimedia

    We propose to study the low-spin level structure of the $^{207}$Tl nucleus populated by the beta decay of $^{207}$Hg. While $^{207}$Tl is a single-proton hole nucleus, the majority of the observed states will have threeparticle structure thus requiring the breaking of the neutron or proton core, or a collective octupole phonon coupled to the single proton hole. Thus information will be obtained on the single particle orbitals in the vicinity of the N=126 and Z=82 magic numbers, and on the size of the shell gap. The results will be used to improve the predictive power of the shell model for more exotic nuclei as we move to lighter N=126 nuclei.The experiment will use the ISOLDE Decay station, and will take advantage of the $^{207}$Hg beam from the molten lead target. A test on the feasibility to produce $^{208}$Hg beam from the same target, with the aim to study the beta-decay into $^{208}$Tl, could be performed at the same time.

  16. Timescales of Kozai-Lidov oscillations at quadrupole and octupole order in the test particle limit

    CERN Document Server

    Antognini, Joseph M O

    2015-01-01

    Kozai-Lidov (KL) oscillations in hierarchical triple systems have found application to many astrophysical contexts, including planet formation, type Ia supernovae, and supermassive black hole dynamics. The period of these oscillations is known at the order-of-magnitude level, but dependences on the initial mutual inclination or inner eccentricity are not typically included. In this work I calculate the period of KL oscillations ($t_{\\textrm{KL}}$) exactly in the test particle limit at quadrupole order (TPQ). I explore the parameter space of all hierarchical triples at TPQ and show that except for triples on the boundary between libration and rotation, the period of KL oscillations does not vary by more than a factor of a few. The exact period may be approximated to better than 2 per cent for triples with mutual inclinations between 60$^{\\circ}$ and 120$^{\\circ}$ and initial eccentricities less than $\\sim$0.3. In addition, I derive an analytic expression for the period of octupole-order oscillations due to the...

  17. Delta I = 1 staggering in octupole bands of light actinides "Beat" patterns

    CERN Document Server

    Bonatsos, Dennis; Drenska, S B; Karoussos, N; Minkov, N; Raychev, P P; Roussev, R P

    2001-01-01

    The Delta I = 1 staggering (odd--even staggering) in octupole bands of light actinides is found to exhibit a ``beat'' behaviour as a function of the angular momentum I, forcing us to revise the traditional belief that this staggering decreases gradually to zero and then remains at this zero value. Various algebraic models (spf-Interacting Boson Model, spdf-IBM, Vector Boson Model, Nuclear Vibron Model) are shown to predict in their su(3) limits constant staggering for this case, being thus unable to describe the ``beat'' behaviour. An explanation of the ``beat'' behaviour is given in terms of two Dunham expansions (expansions in terms of powers of I(I+1)) with slightly different sets of coefficients for the ground state band and the negative parity band, the difference in the values of the coefficients being attributed to Coriolis couplings to other negative parity bands. Similar ``beat'' patterns have already been seen in rotational bands of some diatomic molecules, like AgH.

  18. Space charge and octupole driven resonance trapping observed at the CERN proton synchrotron

    CERN Document Server

    Franchetti, Giuliano; Giovannozzi, Massimo; Martini, Michel; Métral, Elias; 10.1103/PhysRevSTAB.6.124201

    2003-01-01

    The combined effect of space charge and nonlinear resonance on beam loss and emittance was measured in a benchmarking experiment over a 1.2 s long flat bottom at 1.4 GeV kinetic energy in the presence of a single controllable octupole. By lowering the working point towards the resonance, a gradual transition from a loss-free core emittance blowup to a regime dominated by continuous loss was found. We compare the observation with 3D simulations based on a new analytical space charge model and obtain good agreement in the emittance blowup regime. Our explanation is in terms of the synchrotron oscillation, which causes a periodic tune modulation due to space charge, and leads to trapping and detrapping on the resonance islands. For working points very close to the resonance this induces a beam halo with large radius. The underlying dynamics is studied in detail, and it is claimed that the predicted halo in conjunction with a reduced dynamic aperture for the real machine lattice is the source of the loss observed...

  19. Tuning the electronic properties of boron nitride nanotube by mechanical uni-axial deformation: a DFT study

    Science.gov (United States)

    Ju, Shin-Pon; Wang, Yao-Chun; Lien, Ting-Wei

    2011-12-01

    The effect of uni-axial strain on the electronic properties of (8,0) zigzag and (5,5) armchair boron nitride nanotubes (BNNT) is addressed by density functional theory calculation. The stress-strain profiles indicate that these two BNNTS of differing types display very similar mechanical properties, but there are variations in HOMO-LUMO gaps at different strains, indicating that the electronic properties of BNNTs not only depend on uni-axial strain, but on BNNT type. The variations in nanotube geometries, partial density of states of B and N atoms, B and N charges are also discussed for (8,0) and (5,5) BNNTs at different strains.

  20. Tuning the electronic properties of boron nitride nanotube by mechanical uni-axial deformation: a DFT study

    Directory of Open Access Journals (Sweden)

    Ju Shin-Pon

    2011-01-01

    Full Text Available Abstract The effect of uni-axial strain on the electronic properties of (8,0 zigzag and (5,5 armchair boron nitride nanotubes (BNNT is addressed by density functional theory calculation. The stress-strain profiles indicate that these two BNNTS of differing types display very similar mechanical properties, but there are variations in HOMO-LUMO gaps at different strains, indicating that the electronic properties of BNNTs not only depend on uni-axial strain, but on BNNT type. The variations in nanotube geometries, partial density of states of B and N atoms, B and N charges are also discussed for (8,0 and (5,5 BNNTs at different strains.

  1. Influence of austenization parameters on physical-mechanical properties of noniradiated and neutron-irradiated 12Cr18Ni10Ti steel deformed in temperature interval 25-100 oC

    International Nuclear Information System (INIS)

    The influence of austenization temperature on characteristics of hardness, ductility and magnetic properties of non-irradiated and irradiated with neutrons 12Cr18Ni10Ti steel was investigated. It was shown that a decrease in austenization temperature from 1150 to 1050 oC results in a negative impact on martensitic ???' transformation at cold deformation.

  2. Elastic Properties in Tension and Shear of High Strength Nonferrous Metals and Stainless Steel - Effect of Previous Deformation and Heat Treatment

    Science.gov (United States)

    Mebs, R W; Mcadam, D J

    1947-01-01

    A resume is given of an investigation of the influence of plastic deformation and of annealing temperature on the tensile and shear elastic properties of high strength nonferrous metals and stainless steels in the form of rods and tubes. The data were obtained from earlier technical reports and notes, and from unpublished work in this investigation. There are also included data obtained from published and unpublished work performed on an independent investigation. The rod materials, namely, nickel, monel, inconel, copper, 13:2 Cr-Ni steel, and 18:8 Cr-Ni steel, were tested in tension; 18:8 Cr-Ni steel tubes were tested in shear, and nickel, monel, aluminum-monel, and Inconel tubes were tested in both tension and shear. There are first described experiments on the relationship between hysteresis and creep, as obtained with repeated cyclic stressing of annealed stainless steel specimens over a constant load range. These tests, which preceded the measurements of elastic properties, assisted in devising the loading time schedule used in such measurements. From corrected stress-set curves are derived the five proof stresses used as indices of elastic or yield strength. From corrected stress-strain curves are derived the secant modulus and its variation with stress. The relationship between the forms of the stress-set and stress-strain curves and the values of the properties derived is discussed. Curves of variation of proof stress and modulus with prior extension, as obtained with single rod specimens, consist in wavelike basic curves with superposed oscillations due to differences of rest interval and extension spacing; the effects of these differences are studied. Oscillations of proof stress and modulus are generally opposite in manner. The use of a series of tubular specimens corresponding to different amounts of prior extension of cold reduction gave curves almost devoid of oscillation since the effects of variation of rest interval and extension spacing were removed. Comparison is also obtained between the variation of the several properties, as measured in tension and in shear. The rise of proof stress with extension is studied, and the work-hardening rates of the various metals evaluated. The ratio between the tensile and shear proof stresses for the various annealed and cold-worked tubular metals is likewise calculated. The influence of annealing or tempering temperature on the proof stresses and moduli for the cold-worked metals and for air-hardened 13:2 Cr-Ni steel is investigated. An improvement of elastic strength generally is obtained, without important loss of yield strength, by annealing at suitable temperature. The variation of the proof stress and modulus of elasticity with plastic deformation or annealing temperature is explained in terms of the relative dominance of three important factors: namely, (a) internal stress, (b) lattice-expansion or work-hardening, and (c) crystal reorientation. Effective values of Poisson's ratio were computed from tensile and shear moduli obtained on tubular specimens. The variation of Poisson's ratio with plastic deformation and annealing temperature is explained in terms of the degree of anisotropy produced by changes of (a) internal stress and (b) crystal orientation.

  3. High-temperature deformation behavior and mechanical properties of rapidly solidified Al-Li-Co and Al-Li-Zr alloys

    International Nuclear Information System (INIS)

    The deformation behavior at 25-300 C of rapidly solidified Al-3Li-0.6Co and Al-3Li-0.3Zr alloys was studied by tensile property measurements and transmission electron microscopic examination of dislocation substructures. In binary Al-3Li and Al-3Li-Co alloys, the modulus normalized yield stress increases with an increase in temperature up to 150 C and then decreases. The yield stress at 25 C of Al-3Li-0.3Zr alloys is 180-200 MPa higher than that of Al-3Li alloys. However, the yield stress of the Zr-containing alloy decreases drastically with increasing temperatures above 75 C. The short-term yield stresses at 100-200 C of the Al-3Li-based alloys are higher than that of the conventional high-temperature Al alloys. The temperature dependences of the flow stresses of the alloys were analyzed in terms of the magnitudes and temperature dependences of the various strengthening contributions in the two alloys. The dislocation substructures at 25-300 C were correlated with mechanical properties. 19 references

  4. Note on a search for the two-octupole phonon 2 sup + state in sup 2 sup 0 sup 8 Pb with resonant photon scattering

    CERN Document Server

    Enders, J; Eberth, J; Fitzler, A; Fransen, C; Herzberg, R D; Kaiser, H; Käubler, L; Neuman-Cosel, P V; Pietralla, N; Ponomarev, V Yu; Richter, A; Schnare, H; Schwengner, R; Skoda, S; Thomas, H G; Tiesler, H; Weisshaar, D; Wiedenhöver, I

    2000-01-01

    Results of a sup 2 sup 0 sup 8 Pb (gamma,gamma') experiment are presented aiming at an identification of the 2 sup + member of the long-sought two-octupole phonon multiplet. Four E2 excitations have been observed below 6.5 MeV excitation energy, two of them for the first time. However, in contrast to new results of calculations within the quasiparticle-phonon nuclear model (QPM), no obvious candidate for the two-octupole phonon vibration could be found in the present study. We discuss the J suppi=2 sup + states detected in this as well as previous experiments with respect to their possible two-octupole phonon structure.

  5. An Investigation of Physico-Mechanical Properties of Ultrafine-Grained Magnesium Alloys Subjected to Severe Plastic Deformation

    Science.gov (United States)

    Kozulyn, A. A.; Skripnyak, V. A.; Krasnoveikin, V. A.; Skripnyak, V. V.; Karavatskii, A. K.

    2015-01-01

    The results of investigations of physico-mechanical properties of specimens made from the structural Mg-based alloy (Russian grade Ma2-1) in its coarse-grained and ultrafine-grained states after SPD processing are presented. To form the ultrafine-grained structure, use was made of the method of orthogonal equal-channel angular pressing. After four passes through the die, a simultaneous increase was achieved in microhardness, yield strength, ultimate tensile strength and elongation to failure under conditions of uniaxial tensile loading.

  6. Recovery and recrystallization during high temperature deformation

    International Nuclear Information System (INIS)

    Microstructural changes in metals occurring during and after hot working are considered and their effects on mechanical properties of the worked material are described. Sections are included on recrystallization, recovery, and effects of deformation on mechanical properties. 136 references

  7. Comparison between the sandy and the shaly facies of the Opalinus Clay (Mont Terri, Switzerland): mechanical properties obtained from triaxial deformation, mineralogical composition and micro fabric

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. In Switzerland, the international research project Mont Terri investigates the Opalinus Clay (Jurassic formation) in the underground rock laboratory (URL) Mont Terri. The Opalinus Clay is subdivided into different facies (sandy, shaly, and carbonate rich facies). In the Mont Terri URL the sandy facies is less abundant and only a relatively thin layer of the carbonate rich facies is present. The currently favored HLRW repository site in Switzerland, however, is supposed to be in the sandy facies of the Opalinus Clay. Yet, most of the investigations focused on the shaly facies. Generally the understanding of the relation of properties and performances of clays and clay-stones is poor which is relevant for mineralogical micro fabric but also mechanical processes. For the safety assessment of the repository models describing both chemical and mechanical processes are required. Such models have to be based on a solid understanding of the mechanisms behind the processes considered. With respect to the understanding of the deformation behavior of different Opalinus Clay samples, Klinkenberg et al. (2009) found the carbonates to play a major role. For different samples of the shaly facies they found carbonate to represent a kind of predetermined breaking planes. Therefore, carbonate rich materials showed lower mechanical strengths. Interestingly, they also observed the opposite when considering samples of the Callovo-Oxfordiaonsidering samples of the Callovo-Oxfordian clay, which is investigated in France. Considering the micro fabric of all samples suggests that the carbonate - mechanical strength relation depends on the type and amount of carbonates. Therefore, Kaufhold et al. investigated the micro fabric - mechanical strength relation of the sandy facies. They concluded that the sandy facies is comparable with the investigated samples of the Callovo-Oxfordian clay. The mechanical behavior of the shaly facies was already investigated. A detailed comparison of samples from both main facies of the Opalinus clay, however, is missing. In this study, therefore, the investigation of the sandy facies and shaly facies with focus on the relation between micro fabric, mineralogical composition, and mechanical deformation behavior is presented. The sandy and the shaly facies both show the same mineral inventory but different contents. The shaly facies has a clay mineral content between 60 to 70 wt% (within 10-15 wt% swellable phases), whereas the sandy facies only has a clay mineral content of 15-25% (within dev.peak approximately twice as high as it was found for the shaly facies. The results are supposed to improve the understanding of the mechanical properties of clays, particularly with respect to the variability of mineral composition, micro fabric, and mechanical behavior. (authors)

  8. A comparison of two magnetic ultra-cold neutron trapping concepts using a Halbach-octupole array

    CERN Document Server

    Leung, K; Martin, F; Rosenau, F; Simson, M; Zimmer, O

    2015-01-01

    This paper describes a new magnetic trap for ultra-cold neutrons (UCNs) made from a 1.2 m long Halbach-octupole array of permanent magnets with an inner bore radius of 47 mm combined with an assembly of superconducting end coils and bias field solenoid. The use of the trap in a vertical, magneto-gravitational and a horizontal setup are compared in terms of the effective volume and ability to control key systematic effects that need to be addressed in high precision neutron lifetime measurements.

  9. Hyperfine structure of the metastable P32 state of alkaline-earth-metal atoms as an accurate probe of nuclear magnetic octupole moments

    Science.gov (United States)

    Beloy, K.; Derevianko, A.; Johnson, W. R.

    2008-01-01

    Measuring the hyperfine structure (HFS) of long-lived P32 states of divalent atoms may offer the opportunity of extracting relatively unexplored nuclear magnetic octupole and electric hexadecapole moments. Here, using relativistic many-body methods of atomic structure and the nuclear shell model, we evaluate the effect of these higher nuclear moments on the hyperfine structure. We find that the sensitivity of HFS interval measurements in S87r needed to reveal the perturbation caused by the nuclear octupole moment is on the order of kHz. The results of similar analyses for B9e , M25g , and C43a are also reported.

  10. Hyperfine structure of the metastable 3P2 state of alkaline earth atoms as an accurate probe of nuclear magnetic octupole moments

    CERN Document Server

    Beloy, K; Johnson, W R

    2007-01-01

    Measuring the hyperfine structure (HFS) of long-lived $^3P_2$ states of divalent atoms may offer the opportunity of extracting relatively unexplored nuclear magnetic octupole and electric hexadecapole moments. Here, using relativistic many-body methods of atomic structure and the nuclear shell model, we evaluate the effect of these higher nuclear moments on the hyperfine structure. We find that the sensitivity of HFS interval measurements in $^{87}$Sr needed to reveal the perturbation caused by the nuclear octupole moment is on the order of kHz. Results of similar analyses for $^{9}$Be, $^{25}$Mg, and $^{43}$Ca are also reported.

  11. Cyclic Plastic Deformation and Welding Simulation:

    OpenAIRE

    Ten Horn, C. H. L. J.

    2003-01-01

    One of the concerns of a fitness for purpose analysis is the quantification of the relevant material properties. It is known from experiments that the mechanical properties of a material can change due to a monotonic plastic deformation or a cyclic plastic deformation. For a fitness for purpose analysis to be accurate in these cases, it has to take into account the current mechanical properties of the material. The problem is that the current properties may not always be known and retrieving ...

  12. Effect of warm deformation on microstructure and mechanical properties of a layered and nanostructured 304 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Chen, A.Y.; Shi, S.S.; Tian, H.L. [School of Material Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093 (China); Ruan, H.H. [Department of Mechanical Engineering, Hong Kong University of Science and Technology, Hong Kong (China); Li, X. [School of Material Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093 (China); Pan, D., E-mail: feiyu.dpan@gmail.com [School of Material Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093 (China); Lu, J. [College of Science and Engineering, City University of Hong Kong, Hong Kong (China)

    2014-02-10

    A layered and nanostructured (LN) stainless steel was fabricated by surface mechanical attrition treatment (SMAT) combined with warm co-rolling (WCR) in order to improve the low ductility of nanostructured metallic materials. The influences of rolling temperature and strain on the microstructure are investigated. The microstructure of LN steel is characterized by methods of transmission electron microscopy (TEM), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The experimental results reveal that the microstructure of LN steels presents a periodic distribution of nanocrystalline layer, ultra-fine grained layer and coarse grained layer with graded transition of grain size. The integrated effects of SMAT and WCR on the refinement of grain size, involving in dislocation subdivision, twinning and dynamic recrystallization, are discussed. The tensile properties of LN steels exhibit both high strength and good ductility resulting from good work hardening behavior. The strengthening mechanisms by grain size refinement, ??-martensite transformation and twinning are explored.

  13. Effect of warm deformation on microstructure and mechanical properties of a layered and nanostructured 304 stainless steel

    International Nuclear Information System (INIS)

    A layered and nanostructured (LN) stainless steel was fabricated by surface mechanical attrition treatment (SMAT) combined with warm co-rolling (WCR) in order to improve the low ductility of nanostructured metallic materials. The influences of rolling temperature and strain on the microstructure are investigated. The microstructure of LN steel is characterized by methods of transmission electron microscopy (TEM), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The experimental results reveal that the microstructure of LN steels presents a periodic distribution of nanocrystalline layer, ultra-fine grained layer and coarse grained layer with graded transition of grain size. The integrated effects of SMAT and WCR on the refinement of grain size, involving in dislocation subdivision, twinning and dynamic recrystallization, are discussed. The tensile properties of LN steels exhibit both high strength and good ductility resulting from good work hardening behavior. The strengthening mechanisms by grain size refinement, ??-martensite transformation and twinning are explored

  14. Consolidation state of incoming sediments to the Nankai Trough subduction zone: Implications for sediment deformation and properties

    Science.gov (United States)

    Kitajima, Hiroko; Saffer, Demian M.

    2014-07-01

    hydromechanical properties of accreted and underthrust sediments are key parameters controlling the mechanics of earthquakes and the development of fluid pressure in subduction zones. We conducted consolidation tests on sediments from the Philippine Sea Plate (PSP) in the Nankai Trough to understand the consolidation state and hydraulic properties of the incoming sediment section before its incorporation into the subduction zone. We used mudstone and sandstone cores sampled from the Integrated Ocean Drilling Program Nankai Trough Seismogenic Zone Experiment at two reference sites (Site C0011 located on a basement low; and Site C0012 located on a basement high). Our experimental results indicate that most of the mudstone samples are normally consolidated or overconsolidated, with overconsolidation ratios (OCR) ranging from 0.89 to 2.52 at Site C0011 and 0.86 to 3.85 at Site C0012. Higher OCR values at Site C0012, at least at shallow depths, are likely caused by erosional unloading. This implies that Site C0011 may serve as a better geotechnical reference site. We also find that mudstones accreted along the frontal thrust are severely overconsolidated relative to coeval mudstones at Site C0011, which likely reflects enhanced consolidation due to increased horizontal tectonic stress. Sandstones in the incoming section on the PSP exhibit 2-3 orders of magnitude higher in situ permeability than the mudstones, and the siliciclastic sandstone we tested maintains a high permeability at stresses up to at least 70 MPa, suggesting that the sandstones may act as important pathways for drainage or pore pressure translation from depths of several kilometers.

  15. Deformation microstructures

    DEFF Research Database (Denmark)

    Hansen, N.; Huang, X.

    2004-01-01

    Microstructural characterization and modeling has shown that a variety of metals deformed by different thermomechanical processes follows a general path of grain subdivision, by dislocation boundaries and high angle boundaries. This subdivision has been observed to very small structural scales of the order of 10 nm, produced by deformation under large sliding loads. Limits to the evolution of microstructural parameters during monotonic loading have been investigated based on a characterization by transmission electron microscopy. Such limits have been observed at an equivalent strain of about 10 for the misorientation angle and the density of high angle boundaries. However, the spacing between boundaries decreases with increasing strain without saturation even at extreme strains. The observed changes in microstructural parameters lead to a discussion of the flow stress/strain relationship.

  16. Deformations of Oka manifolds

    CERN Document Server

    Larusson, Finnur

    2011-01-01

    We investigate the behaviour of the Oka property with respect to deformations of compact complex manifolds. We show that in a family of compact complex manifolds, the set of Oka fibres corresponds to a G-delta subset of the base. We give a necessary and sufficient condition for the limit fibre of a sequence of Oka fibres to be Oka in terms of a new uniform Oka property. We show that if the fibres are tori, then the projection is an Oka map. Finally, we consider holomorphic submersions with noncompact fibres.

  17. Evolution of quadrupole and octupole collectivity north-east of $^{132}$ Sn: the event Te and Xe isotopes

    CERN Multimedia

    We propose to study excited states in isotopes north-east of the doubly-magic 132Sn by $\\gamma$-ray spectroscopy following \\safe" Coulomb excitation. The experiment aims to the determine B(E2) and B(E3) values to follow the evolution of quadrupole and octupole collectivity when going away from the shell closures at $\\{Z}$ = 50 and $\\{N}$ = 82. The B(E2; 0$^+_{gs}$ $\\rightarrow$ 2$^+_{1}$) values in the even isotopes $^{138-144}$Xe have been measured at REX-ISOLDE and the systematic trend towards neutron-rich nuclei is well described even by an empirical Grodzins-type formula. An increasing dipole moment observed for $^{140;142}$Xe is interpreted as indirect signature of increasing octupole correlations peaking at $\\{N}$ = 88. So far, no $\\{B}({E}$3) values are known. In contrast to the Xe isotopes, the Te ones, in particular $^{136}$Te, are known for their notoriously irregular behaviour. In order to understand the nuclear structure also on a microscopic basis, the isotope $^{136}$Te with just one pair of pro...

  18. Magnetic octupole order in Ce0.7La0.3B6: A polarized neutron diffraction study

    International Nuclear Information System (INIS)

    Recently, in phase IV of CexLa1-xB6, weak but distinct superlattice reflections from the order parameter of phase IV have been detected by our unpolarized neutron scattering experiment [K. Kuwahara, K. Iwasa, M. Kohgi, N. Aso, M. Sera, F. Iga, J. Phys. Soc. Japan 76 (2007) 093702]. The scattering vector dependence of the intensity of superlattice reflections is quite unusual; the intensity is stronger for high scattering vectors. This result strongly indicates that the order parameter of phase IV is the magnetic octupole. However, the possibility that the observed superlattice reflections are due to lattice distortions could not be completely ruled out only on the basis of the unpolarized neutron scattering experiment. To confirm that the superlattice reflections are magnetic, therefore, we have performed a single crystal polarized neutron diffraction experiment on Ce0.7La0.3B6. The obtained result has clearly shown that the time reversal symmetry is broken by the order parameter of phase IV. This is further evidence for the magnetic octupole order in CexLa1-xB6.

  19. Extensional fault zone architecture and deformation band scaling properties in high-porosity sands: example from the Crotone basin (south Italy)

    Science.gov (United States)

    Balsamo, Fabrizio; Storti, Fabrizio; Luca, Aldega

    2013-04-01

    We describe the evolution of the structural architecture of deformation-band-dominated extensional fault zones developed at shallow depth (10-15%) feldspar lithoarenites (200 µm zones varies between few cm up to ~100 m. Fault zones typically consist of a narrow fault core surrounded by thick damage zones which, in turn, contain abundant fault-parallel deformation bands. Fault core and damage zone thickness tend to increase with increasing displacement. The main deformation mechanism in fault cores is particulate flow, with a variable amount of mechanical grain size reduction that progressively increases with increasing fault displacement. The formation of deformation bands involves cataclasis and porosity collapse. XRD analyses performed on both undeformed and faulted sands show a slight increase of phyllosilicates in the fault core rocks, whereas the deformation bands do not show significant mineralogical variations with respect to the host sands. Fault cores and deformation bands show permeability reduction with respect to the host sands up to 3-4 orders of magnitude. The number of deformation bands in damage zone increases with increasing fault displacement. The spacing between adjacent deformation bands, as well as the width of each deformation band, do not show any relationship with fault displacement. They are controlled by the mean grain size of host sands: deformation bands are more closely spaced and thinner in fine sands than in coarse sands. The characterization of the structural and petrophysical architecture of such extensional fault zones provides the basis for transmissibility calculation as a function of fault displacement which may help to predict the hydraulic behaviour of faulted clastic reservoirs and aquifers.

  20. q-deformed Fermions

    CERN Document Server

    Narayana-Swamy, P

    2005-01-01

    This is a study of $q$-Fermions arising from a q-deformed algebra of harmonic oscillators. Two distinct algebras will be investigated. Employing the first algebra, the Fock states are constructed for the generalized Fermions obeying Pauli exclusion principle. The distribution function and other thermodynamic properties such as the internal energy and entropy are derived. Another generalization of fermions from a different q-deformed algebra is investigated which deals with q-fermions not obeying the exclusion principle. Fock states are constructed for this system. The basic numbers appropriate for this system are determined as a direct consequence of the algebra. We also establish the Jackson Derivative, which is required for the q-calculus needed to describe these generalized Fermions.

  1. Octupole excitations in {sup 141,144}Cs and the pronounced decrease of dipole moments with neutron number in odd-Z neutron-rich {sup 141,143,144}Cs

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Y.X. [Physics Department, Vanderbilt University, Nashville, TN 37235 (United States); Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)], E-mail: yxluo@lbl.gov; Rasmussen, J.O. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Hamilton, J.H.; Ramayya, A.V.; Liu, S.H.; Jones, E.F.; Gore, P.M.; Goodin, C. [Physics Department, Vanderbilt University, Nashville, TN 37235 (United States); Stone, N.J. [Department of Physics, Oxford University, Oxford OX1 3PU (United Kingdom); Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States); Zhu, S.J. [Physics Department, Vanderbilt University, Nashville, TN 37235 (United States); Physics Department, Tsinghua University, Beijing 100084 (China); Hwang, J.K.; Li, Ke; Crowell, H.L. [Physics Department, Vanderbilt University, Nashville, TN 37235 (United States); Lee, I.Y. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Ter-Akopian, G.M. [Flerov Laboratory for Nuclear Reactions, JINR, Dubna (Russian Federation); Daniel, A.V. [Physics Department, Vanderbilt University, Nashville, TN 37235 (United States); Flerov Laboratory for Nuclear Reactions, JINR, Dubna (Russian Federation); Joint Institute for Heavy Ion Research, Oak Ridge, TN 37831 (United States); Stoyer, M.A. [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Donangelo, R. [Universidade Federal do Rio de Janeiro, CP 68528, RJ (Brazil); Ma, W.C. [Mississippi State University, Drawer 5167, Mississippi State, MS 39762 (United States); Cole, J.D. [Idaho National Laboratory, Bldg. IRCPL, MS2114, Idaho Falls, ID 83415 (United States)

    2010-07-01

    The level scheme of odd-Z neutron-rich {sup 141}Cs (Z=55, N=86) was extended and expanded and that of {sup 144}Cs (N=89) was identified for the first time by means of {gamma}-{gamma}-{gamma} coincidence measurements of prompt {gamma} rays in the spontaneous fission of {sup 252}Cf with Gammasphere. Spin/parity was assigned to the levels based on angular correlations and level systematics in {sup 141,143}Cs. Parity doublets characteristic of both simplex quantum number s=+i and s=-i were proposed in {sup 141}Cs. The tests by using rotational frequency ratio {omega}{sup -}(I)/{omega}{sup +}(I) imply octupole vibrations in {sup 141}Cs and {sup 143}Cs. B(E1)/B(E2) values and electric dipole moments D{sub 0} were calculated for {sup 141}Cs, and re-determined for {sup 143}Cs. It was found that B(E1)/B(E2) values of {sup 141}Cs are simplex-dependent and the average value is one order of magnitude larger than that of {sup 143}Cs, and the deduced dipole moment D{sub 0} of {sup 141}Cs is considerably larger than that of {sup 143}Cs, and comparable to the N=86 isotone {sup 142}Ba. For {sup 144}Cs the yrast sequence looks like a well-deformed rotational band, but no octupole band structure was identified in this nucleus. The overall variations of D{sub 0} in {sup 141,143,144}Cs exhibit a pronounced drop of dipole moment with increasing neutron number in this odd-Z isotopic chain, which may be analogous in nature to the quenching of D{sub 0} observed in even-even {sup 146}Ba (Z=56, N=90) and {sup 224}Ra (Z=88, N=136), and to the drop of D{sub 0} in the odd-Z neutron-rich {sup 147}La (Z=57, N=90) reported by our collaboration.

  2. Oxide dispersion strengthened ferritic alloys. 14/20% chromium: effects of processing on deformation texture, recrystallization and tensile properties; Alliages ferritiques 14/20% de chrome renforces par dispersion d`oxydes. Effets des procedes de mise en forme sur les textures de deformation, la recristallisation et les proprietes de traction

    Energy Technology Data Exchange (ETDEWEB)

    Regle, H.

    1994-12-31

    The ferritic oxide dispersion strengthened alloys are promising candidates for high temperature application materials, in particular for long life core components of advanced nuclear reactors. The aim of this work is to control the microstructure, in order to optimise the mechanical properties. The two ferritic alloys examined here, MA956 and MA957, are obtained by Mechanical Alloying techniques. They are characterised by quite anisotropic microstructure and mechanical properties. We have investigated the influence of hot and cold working processes (hot extrusion, swaging and cold-drawing) and recrystallization heat treatments on deformation textures, microstructures and tensile properties. The aim was to control the size of the grains and their anisotropic shape, using recrystallization heat treatments. After consolidation and hot extrusion, as-received materials present a extremely fine microstructure with elongated grains and a very strong (110) deformation texture with single-crystal character. At that stage of processing, recrystallization temperature are very high (1450 degrees C for MA957 alloy and 1350 degrees C for MA956 alloy) and materials develop millimetric recrystallized grains. Additional hot extrusion induce a fibre texture. Cold-drawing maintains a fibre texture, but the intensity decreases with increasing cold-work level. For both materials, the decrease of texture intensities correspond to a decrease of the recrystallization temperatures (from 1350 degrees C for a low cold-work level to 750 degrees C for 60 % cold-deformation, case of MA956 alloy) and a refinement of the grain size (from a millimetric size to less than an hundred of micrometer). Swaging develop a cyclic component where the intensity increases with increasing deformation in this case, the recrystallization temperature remains always very high and the millimetric grain size is slightly modified, even though cold-work level increases. (Abstract Truncated)

  3. Effect of petrophysical properties and deformation on vertical zoning of metasomatic rocks in U-bearing volcanic structures: A case of the Strel'tsovka caldera, Transbaikal region

    Science.gov (United States)

    Petrov, V. A.; Andreeva, O. V.; Poluektov, V. V.

    2014-03-01

    The development of vertical zoning of wall-rock metasomatic alteration is considered with the Mesozoic Strel'tsovka caldera as an example. This caldera hosts Russia's largest uranium ore field. Metasomatic rocks with the participation of various phyllosilicates, carbonates, albite, and zeolites are widespread in the ore field. In the eastern block of the caldera, where the main uranium reserves are accommodated, hydromica metasomatic alteration gives way to beresitization with depth. Argillic alteration, which is typical of the western block, is replaced with hydromica and beresite alteration only at a significant depth. Postore argillic alteration is superposed on beresitized rocks in the lower part of the section. Two styles of vertical metasomatic zoning are caused by different modes of deformation in the western and eastern parts of the caldera. Variations of the most important petrophysical properties of host rocks—density, apparent porosity, velocities of P- and S-waves, dynamic Young's modulus, and Poisson coefficient—have been determined by sonic testing of samples taken from different depths. It is suggested that downward migration of the brittle-ductile transition zone could have been a factor controlling facies diversity of metasomatic rocks. Such a migration was caused by a new phase of tectonothermal impact accompanied by an increase in the strain rate or by emplacement of a new portion of heated fluid. Transient subsidence of the brittle-ductile boundary increases the depth of the hydrodynamically open zone related to the Earth's surface and accelerates percolation of cold meteoric water to a greater depth. As a result, the temperature of the hydrothermal solution falls down, increasing the vertical extent of argillic alteration. High-grade uranium mineralization is also localized more deeply than elsewhere.

  4. Monitoring the resonant properties of the magmatic structures of Elbrus volcano based on observation of lithospheric deformations by the Baksan laser interferometer - strainmeter

    Science.gov (United States)

    Milyukov, V.; Myasnikov, A.

    2012-04-01

    The Elbrus volcanic center is located on the northern slope of the main ridge of the Greater Caucasus. It includes Mount Elbrus, a double-top stratovolcano, and a number of small volcanic centers concentrated on its western flank. According to present understandings, the Elbrus volcano falls into the category of the so-called dormant volcanoes that become reactivated. It is a typical volcano of a continental type. During a number of years to study magmatic structures of the Elbrus volcano, their resonant properties and dynamics the new resonant method has been used. The idea of method is simple enough. Magmatic structures, being a resonator, upon incidence of a broadband powerful seismic signal generate the secondary seismic waves, having a set of resonant modes and containing information about physical and mechanical properties of structure inhomogeneities. These resonant modes are determined by geometrical parameters and elastic properties of the magma chamber as well as by magma properties. Estimation of the resonant parameters is based on the analysis of lithosphere deformations recorded by the wide-band Baksan laser interferometer-strainmeter with a 75-m armlength which is installed in the underground tunnel of the Baksan Neutrino Observatory, 20 km apart from Mt. Elbrus. Here we report the analysis of the teleseismic signals excited by seven mean-power earthquakes (the magnitude, as a rule, didn't exceed 6), that occurred within 2005-2010 in so-called "a near zone» of the volcano Elbrus (<1500 km). The relative proximity of the earthquake focuses to the volcanic edifice creates the possibility to excite the eigen oscillations of the Elbrus resonant structures (magma chambers), at the same time, the energies of these moderate-power earthquakes are not enough to excite the free oscillations of the Earth. Spectral analysis revealed quite confidently 10 groups of resonance modes in the range of periods of 30 -150 s. In this group of the resonant modes, three modes are stand out with the periods of 62.1 s, 64.3 s, and 67.9 s, which are excited in 100% of seismic events. The intensities of these modes in the spectra are maximal, or close to the maximum. Estimates of Q-factor of the selected regional resonant modes lie in the range 250-300, that assumes that the revealed modes are generated by the structures containing magmatic fluids with a large gas component. The resonant parameters (frequencies and Q-factors of the resonant modes) we have found were interpreted in the framework of contemporary models of magma resonators. We estimated the depth and dimensions of the shallow magma chamber, as well as the properties of the magma fluid which are corroborated by available geological and geophysical evidence. Our interpretation of observational materials suggests that the intrachamber pressure seems to be rising owing to the advent of new portions of hot lava from a deep magma source. The stated approach provides a window to volcano dynamics and lays a foundation of the new "resonant" method for monitoring the state of volcano. This work is supported by the Russian Foundation for Basic Research.

  5. Distributed actuator deformable mirror

    CERN Document Server

    Bonora, Stefano

    2010-01-01

    In this paper we present a Deformable Mirror (DM) based on the continuous voltage distribution over a resistive layer. This DM can correct the low order aberrations (defocus, astigmatism, coma and spherical aberration) using three electrodes with nine contacts leading to an ideal device for sensorless applications. We present a mathematical description of the mirror, a comparison between the simulations and the experimental results. In order to demonstrate the effectiveness of the device we compared its performance with the one of a multiactuator DM of similar properties in the correction of an aberration statistics. At the end of the paper an example of sensorless correction is shown.

  6. New high-spin states of {sup 147}Nd and {sup 145}Ce: Octupole correlation in the N=87 isotones

    Energy Technology Data Exchange (ETDEWEB)

    Venkova, Ts.; Petkov, P. [Univ. Paris-Sud, Orsay (France). CNRS; Bulgarian Academy of Sciences, Sofia (Bulgaria). Inst. of Nuclear Research; Porquet, M.-G.; Astier, A.; Deloncle, I.; Prevost, A. [IN2P3-CNRS/Universite Paris-Sud, CSNSM, Orsay (France); Azaiez, F.; Buta, A.; Curien, D.; Dorvaux, O.; Duchene, G.; Gall, B.J.P.; Khalfallah, F.; Piqueras, I.; Rousseau, M. [IN2P3-CNRS/Universite Louis Pasteur, IReS, Strasbourg Cedex 2 (France); Bogachev, A. [JINR, Dubna, Moscow region (Russian Federation); Durell, J.; Roach, A. [University of Manchester, Department of Physics and Astronomy, Manchester (United Kingdom); Houry, M.; Lucas, R.; Theisen, Ch. [CEA/DSM/DAPNIA/SPhN, Commissariat a l' Energie Atomique, Gif-sur-Yvette Cedex (France); Meyer, M.; Redon, N.; Stezowski, O. [IN2P3-CNRS/Universite Claude Bernard, IPNL, Villeurbanne Cedex (France)

    2005-12-01

    High-spin states of the N=87 nuclei, {sup 147}Nd and {sup 145}Ce, have been populated in the {sup 12}C+{sup 238}U and {sup 18}O+{sup 208}Pb fusion-fission reactions at 90 MeV and 85 MeV bombarding energy, respectively. The emitted {gamma}-radiation was detected using the Euroball III and IV arrays. High-spin states of the {sup 147}Nd isotope have been identified for the first time. The high-spin yrast and near-to-yrast structures of the {sup 145}Ce nucleus have been considerably extended. The newly observed structures, discussed by analogy with the neighbouring isotones, show the coupling of an h{sub 9/2} neutron to the quadrupole and octupole excitations of the core. (orig.)

  7. New high-spin states of 147Nd and 145Ce: Octupole correlation in the N=87 isotones

    International Nuclear Information System (INIS)

    High-spin states of the N=87 nuclei, 147Nd and 145Ce, have been populated in the 12C+238U and 18O+208Pb fusion-fission reactions at 90 MeV and 85 MeV bombarding energy, respectively. The emitted ?-radiation was detected using the Euroball III and IV arrays. High-spin states of the 147Nd isotope have been identified for the first time. The high-spin yrast and near-to-yrast structures of the 145Ce nucleus have been considerably extended. The newly observed structures, discussed by analogy with the neighbouring isotones, show the coupling of an h9/2 neutron to the quadrupole and octupole excitations of the core. (orig.)

  8. Developing a Virtual Rock Deformation Laboratory

    Science.gov (United States)

    Zhu, W.; Ougier-simonin, A.; Lisabeth, H. P.; Banker, J. S.

    2012-12-01

    Experimental rock physics plays an important role in advancing earthquake research. Despite its importance in geophysics, reservoir engineering, waste deposits and energy resources, most geology departments in U.S. universities don't have rock deformation facilities. A virtual deformation laboratory can serve as an efficient tool to help geology students naturally and internationally learn about rock deformation. Working with computer science engineers, we built a virtual deformation laboratory that aims at fostering user interaction to facilitate classroom and outreach teaching and learning. The virtual lab is built to center around a triaxial deformation apparatus in which laboratory measurements of mechanical and transport properties such as stress, axial and radial strains, acoustic emission activities, wave velocities, and permeability are demonstrated. A student user can create her avatar to enter the virtual lab. In the virtual lab, the avatar can browse and choose among various rock samples, determine the testing conditions (pressure, temperature, strain rate, loading paths), then operate the virtual deformation machine to observe how deformation changes physical properties of rocks. Actual experimental results on the mechanical, frictional, sonic, acoustic and transport properties of different rocks at different conditions are compiled. The data acquisition system in the virtual lab is linked to the complied experimental data. Structural and microstructural images of deformed rocks are up-loaded and linked to different deformation tests. The integration of the microstructural image and the deformation data allows the student to visualize how forces reshape the structure of the rock and change the physical properties. The virtual lab is built using the Game Engine. The geological background, outstanding questions related to the geological environment, and physical and mechanical concepts associated with the problem will be illustrated on the web portal. In addition, some web based data collection tools are available to collect student feedback and opinions on their learning experience. The virtual laboratory is designed to be an online education tool that facilitates interactive learning.; Virtual Deformation Laboratory

  9. Construction of Miniversal Deformations of Lie Algebras

    OpenAIRE

    Fialowski, Alice; Fuchs, Dmitry

    2000-01-01

    We consider deformations of finite or infinite dimensional Lie algebras over a field of characteristic 0. There is substantial confusion in the literature if one tries to describe all the non-equivalent deformations of a given Lie algebra. It is known that there is in general no "universal" deformation of the Lie algebra L with a commutative algebra base A with the property that for any other deformation of L with base B there exists a unique homomorphism f: A -> B that indu...

  10. Foldover-free shape deformation for biomedicine.

    Science.gov (United States)

    Yu, Hongchuan; Zhang, Jian J; Lee, Tong-Yee

    2014-04-01

    Shape deformation as a fundamental geometric operation underpins a wide range of applications, from geometric modelling, medical imaging to biomechanics. In medical imaging, for example, to quantify the difference between two corresponding images, 2D or 3D, one needs to find the deformation between both images. However, such deformations, particularly deforming complex volume datasets, are prone to the problem of foldover, i.e. during deformation, the required property of one-to-one mapping no longer holds for some points. Despite numerous research efforts, the construction of a mathematically robust foldover-free solution subject to positional constraints remains open. In this paper, we address this challenge by developing a radial basis function-based deformation method. In particular we formulate an effective iterative mechanism which ensures the foldover-free property is satisfied all the time. The experimental results suggest that the resulting deformations meet the internal positional constraints. In addition to radial basis functions, this iterative mechanism can also be incorporated into other deformation approaches, e.g. B-spline based FFDs, to develop different deformable approaches for various applications. PMID:24374231

  11. Nanoscale Deformable Optics

    Science.gov (United States)

    Strauss, Karl F.; Sheldon, Douglas J.

    2011-01-01

    Several missions and instruments in the conceptual design phase rely on the technique of interferometry to create detectable fringe patterns. The intimate emplacement of reflective material upon electron device cells based upon chalcogenide material technology permits high-speed, predictable deformation of the reflective surface to a subnanometer or finer resolution with a very high degree of accuracy. In this innovation, a layer of reflective material is deposited upon a wafer containing (perhaps in the millions) chalcogenic memory cells with the reflective material becoming the front surface of a mirror and the chalcogenic material becoming a means of selectively deforming the mirror by the application of heat to the chalcogenic material. By doing so, the mirror surface can deform anywhere from nil to nanometers in spots the size of a modern day memory cell, thereby permitting realtime tuning of mirror focus and reflectivity to mitigate aberrations caused elsewhere in the optical system. Modern foundry methods permit the design and manufacture of individual memory cells having an area of or equal to the Feature (F) size of the design (assume 65 nm). Fabrication rules and restraints generally require the instantiation of one memory cell to another no closer than 1.5 F, or, for this innovation, 90 nm from its neighbor in any direction. Chalcogenide is a semiconducting glass compound consisting of a combination of chalcogen ions, the ratios of which vary according to properties desired. It has been shown that the application of heat to cells of chalcogenic material cause a large alteration in resistance to the range of 4 orders of magnitude. It is this effect upon which chalcogenidebased commercial memories rely. Upon removal of the heat source, the chalcogenide rapidly cools and remains frozen in the excited state. It has also been shown that the chalcogenide expands in volume because of the applied heat, meaning that the coefficient of expansion of chalcogenic materials is larger than 1. In this innovation, chalcogenidebased cells are addressed (as though they are a memory), and heated and cooled according to well-established criteria. In doing so, the exact size of chalcogenide cell deformation is known and predictable; therefore, the deformation of the reflective surface is, likewise, known and predictable. Control electronics can also be implemented so that a closed-loop feedback can be maintained. Changing the contents of the chalcogenide memory cells can compensate for any change in environmental effects that might cause a change in optical path. This real-time control provides significant control and stability in use conditions.

  12. Triaxially deformed relativistic point-coupling model for ? hypernuclei: A quantitative analysis of the hyperon impurity effect on nuclear collective properties

    Science.gov (United States)

    Xue, W. X.; Yao, J. M.; Hagino, K.; Li, Z. P.; Mei, H.; Tanimura, Y.

    2015-02-01

    Background: The impurity effect of hyperons on atomic nuclei has received a renewed interest in nuclear physics since the first experimental observation of appreciable reduction of E 2 transition strength in low-lying states of the hypernucleus ?7Li . Many more data on low-lying states of ? hypernuclei will be measured soon for s d -shell nuclei, providing good opportunities to study the ? impurity effect on nuclear low-energy excitations. Purpose: We carry out a quantitative analysis of the ? hyperon impurity effect on the low-lying states of s d -shell nuclei at the beyond-mean-field level based on a relativistic point-coupling energy density functional (EDF), considering that the ? hyperon is injected into the lowest positive-parity (?s) and negative-parity (?p) states. Method: We adopt a triaxially deformed relativistic mean-field (RMF) approach for hypernuclei and calculate the ? binding energies of hypernuclei as well as the potential-energy surfaces (PESs) in the (? ,? ) deformation plane. We also calculate the PESs for the ? hypernuclei with good quantum numbers by using a microscopic particle rotor model (PRM) with the same relativistic EDF. The triaxially deformed RMF approach is further applied in order to determine the parameters of a five-dimensional collective Hamiltonian (5DCH) for the collective excitations of triaxially deformed core nuclei. Taking 25,27Mg ? and Si31? as examples, we analyze the impurity effects of ?s and ?p on the low-lying states of the core nuclei. Results: We show that ?s increases the excitation energy of the 21+ state and decreases the E 2 transition strength from this state to the ground state by 12 %to17 % . On the other hand, ?p tends to develop pronounced energy minima with larger deformation, although it modifies the collective parameters in such a way that the collectivity of the core nucleus can be either increased or decreased. Conclusions: The quadrupole deformation significantly affects the ? binding energies of deformed hypernuclei. A beyond-mean-field approach with the dynamical correlations due to restoration of broken symmetries and shape fluctuation is essential in order to study the ? impurity effect in a quantitative way.

  13. Strong M1 components in 3{sup -}{sub i}{yields}3{sup -}{sub 1} in nearly spherical nuclei: Evidence for isovector-octupole excitations

    Energy Technology Data Exchange (ETDEWEB)

    Scheck, Marcus [IKP, TU-Darmstadt (Germany); Dept. of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Butler, Peter A. [Dept. of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Fransen, Christoph [WNSL, Yale University, New Haven, CT (United States); Werner, Volker [IKP, Universitaet zu Koeln (Germany); Yates, Steven W. [Dept. of Physics and Astronomy, University of Kentucky, Lexington, KY (United States); Dept. of Chemistry, University of Kentucky, Lexington, KY (United States)

    2011-07-01

    An evaluation of data obtained in (n,n{sup '}{gamma}) experiments reveals strong M1 3{sup -}{sub i} {yields} 3{sup -}{sub 1} transitions in nuclei near the N=50 ({sup 92}Zr, {sup 94}Mo and {sup 96}Mo), Z=50 ({sup 112}Cd and {sup 114}Cd) and N=82 ({sup 144}Nd) shell closures. The observed left angle 3{sub 1}{sup -} M1 3{sub i}{sup -} right angle matrix elements scale with the left angle 2{sub 1}{sup +} parallel M1 parallel 2{sup +}{sub ms} right angle matrix elements, and the energy difference between the initial 3{sup -}{sub i} state and the 3{sup -}{sub 1} octupole phonon is proportional to the left angle 3{sup -}{sub 1} parallel E3 parallel 0{sup +}{sub gs} right angle matrix element. The possibility of assigning the states of interest as octupole mixed-symmetry states is discussed.

  14. Enhancement of nuclear Schiff moments and time reversal violation in atoms due to combination of soft nuclear octupole and quadrupole vibrations

    CERN Document Server

    Lisetskiy, A F; Zelevinsky, V G

    2003-01-01

    Nuclear forces violating parity and time reversal invariance P,T-odd produce P,T-odd nuclear moments, for example, the nuclear Schiff moment. In turn, this moment can induce the electric dipole moment (EDM) in the atom. The contribution to the Schiff moment from the soft collective quadrupole and octupole vibrations in spherical nuclei is calculated in the framework of the quasiparticle random phase approximation with separable quadrupole and octupole forces. The values of nuclear Schiff moments predicted for odd 217-221Ra and 217-221Ra isotopes indicate a possibility of enhancement by a factor of 50 or more as compared to the experimentally studied spherical nuclei 199Hg and 129Xe. Since the EDM in very heavy atoms, such as Ra, Rn, and Fr, has an additional enhancement rapidly increasing with nuclear charge $Z$, the EDM enhancement can exceed two orders of magnitude. We discuss the nuclear structure effects causing an enhancement of the Schiff moment.

  15. Interrelation between the isoscalar octupole phonon and the proton-neutron mixed-symmetry quadrupole phonon in near-spherical nuclei

    International Nuclear Information System (INIS)

    The interrelation between the octupole phonon and the low-lying proton-neutron mixed-symmetry quadrupole phonon in near-spherical nuclei is investigated. The one-phonon states decay by collective E3 and E2 transitions to the ground state and by relatively strong E1 and M1 transitions to the isoscalar 2+1 state. We apply the proton-neutron version of the interacting boson model including quadrupole and octupole bosons ( sdf -IBM-2). Two F -spin symmetric dynamical symmetry limits of the model, namely the vibrational and the ? -unstable ones, are considered. We derive analytical formulae for excitation energies as well as B(E1) , B(M1) , B(E2) and B(E3) values for a number of transitions between low-lying states

  16. Interrelation between the isoscalar octupole phonon and the proton-neutron mixed-symmetry quadrupole phonon in near-spherical nuclei

    International Nuclear Information System (INIS)

    The interrelation between the octupole phonon and the low-lying proton-neutron mixed-symmetry quadrupole in near-spherical nuclei is investigated. The one-phonon states decay by collective E3 and E2 transitions to the ground state and by relatively strong E1 and M1 transitions to the isoscalar 2+1 state. We apply the proton-neutron version of the Interacting Boson Model including quadrupole and octupole bosons (sdf-IBM-2). Two F-spin symmetric dynamical symmetry limits of the model, namely the vibrational and the ?-unstable ones, are considered. We derived analytical formulae for excitation energies as well as B(E1), B(M1), B(E2), and B(E3) values for a number of transitions between low-lying states. The model well reproduces many known transition strengths in the near spherical nuclei 142Ce and 94Mo. (authors)

  17. Interrelation between the isoscalar octupole phonon and the proton-neutron mixed-symmetry quadrupole phonon in near-spherical nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Smirnova, N.A.; Van Isacker, P. [Grand Accelerateur National d' Ions Lourds (GANIL), 14 - Caen (France); Smirnova, N.A [Paris-11 Univ., 91 - Orsay (France). Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse]|[Institute for Nuclear Physics, Moscow State University (Russian Federation); Pietralla, N. [Institut fur Kernphysik, Universitat zu Koln (Germany)]|[Yale Univ., New Haven, CT (United States). Wright Nuclear Structure Lab; Mizusaki, T. [Tokyo Univ. (Japan). Dept. of Physics

    2000-07-01

    The interrelation between the octupole phonon and the low-lying proton-neutron mixed-symmetry quadrupole in near-spherical nuclei is investigated. The one-phonon states decay by collective E3 and E2 transitions to the ground state and by relatively strong E1 and M1 transitions to the isoscalar 2{sup +}{sub 1} state. We apply the proton-neutron version of the Interacting Boson Model including quadrupole and octupole bosons (sdf-IBM-2). Two F-spin symmetric dynamical symmetry limits of the model, namely the vibrational and the {gamma}-unstable ones, are considered. We derived analytical formulae for excitation energies as well as B(E1), B(M1), B(E2), and B(E3) values for a number of transitions between low-lying states. The model well reproduces many known transition strengths in the near spherical nuclei {sup 142}Ce and {sup 94}Mo. (authors)

  18. Fluid distribution in grain boundaries of natural fine-grained rock salt deformed at low shear stress: implications for rheology and transport properties

    Science.gov (United States)

    Desbois, G.; Urai, J. L.; De Bresser, J. H. P.

    2012-04-01

    We used a combination of broad ion beam (BIB) cross-sectioning and high resolution (cryogenic) SEM to image polished surfaces and corresponding pairs of fractured grain boundaries in an investigation of grain boundary (GB) microstructures and fluid distribution in naturally deformed halite from a salt glacier (Kum Quh, central Iran). At the scale of observations, four types of fluid or gas filled grain boundaries can be distinguished: (1) straight boundaries with thick (up to 10 µm) GB tubes (2) straight boundaries with narrow (about 50 nm) GB tubes (3) wavy (tens of µm wavelength) GB with isolated inclusions of a few µm, and (4) wavy (µm wavelength) GB with small (µm) isolated inclusions. Grain boundary fluid inclusions can have three types of morphologies: the inclusion of Type 1 is intruded completely in one grain, inclusion of Type 2 has its major part included in one grain with a minor part in the second grain and the inclusion of Type 3 is located in both grains. Solid second phases in GB are mainly euhedral anhydrite crystals. The mobility of the brine is shown after cutting the inclusions by BIB in vacuum and fine-grained halite forms efflorescence and precipitates on internal walls of inclusions. At cryogenic temperature, in-situ brine is seen as continuous film in GB of type (1) and (2), and in isolated inclusions in GB of type (3) and (4). The structure of halite-halite contact between isolated fluid inclusions in GB of type (3) and (4) is below the resolution of SEM. GB of type (3) and (4) are interpreted to have formed by healing of mobile fluid films. First results of deformation experiments on the same samples under shear stress corresponding to conditions of natural salt glacier, show very low strain rates (7.43x10-10 s-1 and 1x10-9 s-1), up to one order of magnitude below of expected strain rates by solution precipitation creep. Both microstructures and deformation experiments suggest interfacial energy-driven GB healing, in agreement with the healing criterion of Van Noort et al. (2008). This suggests that PS creep is not active in our samples. Therefore, there is a disagreement with previous microstructural studies (Schléder and Urai, 2007; Desbois et al., 2010) of similar samples, which have shown active PS creep (and dislocation creep) in of salt glaciers. We discuss different explanations for this, which imply that both healing and reactivation of grain boundaries is important in salt glaciers, leading to heterogeneous distribution of deformation mechanisms and strain rates in both space and time. Desbois G., Zavada P., Schléder Z., Urai J.L., 2010. Deformation and recrystallization mechanisms in naturally deformed salt fountain: microstructural evidence for a switch in deformation mechanisms with increased availability of meteoric water and decreased grain size (Qum Kuh, central Iran). Journal of Structural Geology, 32 (4), 580-594. Schléder Z. and Urai J.L. (2007). Deformation and recrystallization mechanisms in mylonitic shear zones in naturally deformed extrusive Eocene-Oligocene rock salt from Eyvanekey plateau and Garmsar hills (central Iran). Journal of structural geology, 29: 241-255. Van Noort, R., Visser, H.J.M., Spiers, C.J., 2008. Influence of grain boundary structure on dissolution controlled pressure solution and retarding effects of grain boundary healing. J. Geophys. Res. 113.

  19. Plastic deformation: Shearing mountains atom by atom

    Energy Technology Data Exchange (ETDEWEB)

    Müllner, Peter, E-mail: petermullner@boisestate.edu [Department of Materials Science and Engineering, Boise State University, Boise, ID 83725 (United States)

    2013-11-15

    Highlights: ? Rocks, wood, ceramics, semiconductors, and metals all deform in the same way, namely by heterogeneous shear banding via hierarchical orthogonal shear modes. ? While the governing principles of deformation are the same for rocks, wood, ceramics, semiconductors, and metals, these materialsdiffer in their microscopic deformation mechanisms and in the width of the shear band, which covers twelve orders of magnitude from angstroms to hundreds of meters. ? Microscopic deformation mechanisms couple to macroscopic deformation mechanisms, i.e. shear banding, through the collective properties of defect groups on the mesoscale. -- Abstract: Conventional wisdom established atomistic defects, dislocations, as agents of plastic deformation. On macroscopic scale, rock, wood, steel, tough ceramics, fiber reinforced composites, and silicon all deform in the same way and produce the same pattern; shear bands. The argumentation presented here, starts on the largest length scale of the problem at hand and leads through a number of hierarchical levels down to the atomistic mechanism. Shear bands develop discontinuously by the motion of a process zone. Locally, i.e. in the process zone, deformation proceeds perpendicularly to the macroscopic shear, in combination with a rotation. The microscopic shear itself may occur again in a discontinuous manner and again orthogonally to the intermediate level and so on at ever smaller scale. Material properties come into play at the highest hierarchical level, i.e. at the smallest length scale where they control the well-known micromechanisms.

  20. Ultrasoft, highly deformable microgels.

    Science.gov (United States)

    Bachman, Haylee; Brown, Ashley C; Clarke, Kimberly C; Dhada, Kabir S; Douglas, Alison; Hansen, Caroline E; Herman, Emily; Hyatt, John S; Kodlekere, Purva; Meng, Zhiyong; Saxena, Shalini; Spears, Mark W; Welsch, Nicole; Lyon, L Andrew

    2015-03-14

    Microgels are colloidally stable, hydrogel microparticles that have previously been used in a range of (soft) material applications due to their tunable mechanical and chemical properties. Most commonly, thermo and pH-responsive poly(N-isopropylacrylamide) (pNIPAm) microgels can be fabricated by precipitation polymerization in the presence of the co-monomer acrylic acid (AAc). Traditionally pNIPAm microgels are synthesized in the presence of a crosslinking agent, such as N,N'-methylenebisacrylamide (BIS), however, microgels can also be synthesized under 'crosslinker free' conditions. The resulting particles have extremely low (microgels, with a Young's modulus of ?10 kPa. Furthermore, ULC microgels are highly deformable as indicated by a high degree of spreading on glass surfaces and the ability to translocate through nanopores significantly smaller than the hydrodynamic diameter of the particles. The size and charge of ULCs can be easily modulated by altering reaction conditions, such as temperature, monomer, surfactant and initiator concentrations, and through the addition of co-monomers. Microgels based on the widely utilized, biocompatible polymer polyethylene glycol (PEG) can also be synthesized under crosslinker free conditions. Due to their softness and deformability, ULC microgels are a unique base material for a wide variety of biomedical applications including biomaterials for drug delivery and regenerative medicine. PMID:25648590

  1. Effect of structural factors on mechanical properties of the magnesium alloy Ma2-1 under quasi-static and high strain rate deformation conditions

    Science.gov (United States)

    Garkushin, G. V.; Razorenov, S. V.; Krasnoveikin, V. A.; Kozulin, A. A.; Skripnyak, V. A.

    2015-02-01

    The elastic limit and tensile strength of deformed magnesium alloys Ma2-1 with different structures and textures were measured with the aim of finding a correlation between the spectrum of defects in the material and the resistance to deformation and fracture under quasi-static and dynamic loading conditions. The studies were performed using specimens in the as-received state after high-temperature annealing and specimens subjected to equal-channel angular pressing at a temperature of 250°C. The anisotropy of strength characteristics of the material after shock compression with respect to the direction of rolling of the original alloy was investigated. It was shown that, in contrast to the quasi-static loading conditions, under the shock wave loading conditions, the elastic limit and tensile strength of the magnesium alloy Ma2-1 after equal-channel angular pressing decrease as compared to the specimens in the as-received state.

  2. Deformation scheme effect on the properties of heat pipes of 12KH1MF steel, hardened by mechanical and heat treatments

    International Nuclear Information System (INIS)

    In the development, by the method of mechanical and heat treatment, of strenghening conditions for tubes from steel 12Kh1MF cold drawing and cold reducing are used at a uniform deformation factor of 11% but with materially different schemes of stress-strain state (different distributions and signs of strains and stresses). The greatest strenthening effect as regards to the ultimate stress and yield stress at a uniform deformation is obtained in the drawing. The poligonizing annealing makes for the levelling out of the drawn and reduced metal, the strength characteristics deteriorate to a greater degree for the drawn metal. The heat resisting characteristics of metal of drawn and reduced tubes at a test temperature of 540degC and high stresses (20-24kgs/mm2) are similar, the plasticity, however, being higher with then drawn tubes. At stresses close to the working ones, metal of the reduced tubes features longer time periods before failure. (author)

  3. Hot tensile properties and deformation response of a gamma/Ni/-gamma prime/Ni3Al/-delta/Ni3Nb/ eutectic composite

    Science.gov (United States)

    Bertorello, H. R.; Hertzberg, R. W.; Kraft, R. W.

    1975-01-01

    Three distinct regions of tensile, deformation and fracture behavior were observed in a 2.5 wt. per cent Al gamma/gamma prime-delta eutectic alloy as the testing temperature was varied. The major finding was an extraordinary ductility maximum at about 550 C. It was shown that this phenomenon is caused by the deflection of transverse cracks at the eutectic grain boundaries when yielding occurs. This delamination between eutectics grains caused by fracture of a gamma prime eutectic grain boundary film leads to a distinctly different 'wood-like' fracture surface morphology. Above 690 C to 926 C, yield and tensile strength values decrease while ductility increase slightly. Cooperative twinning of both phases develops giving rise to block-like deformation of the microstructure quite in parallel to the behavior observed previously in the gamma-delta system.

  4. Effect of surface plastic deformation on the structure and properties of welded tubular joints of 12Kh18N10T steel

    International Nuclear Information System (INIS)

    Samples of tubular electrowelded half-finished articles 40x2 and 40x2.5 mm in size are studied. It is shown that the welded tubes may be calibrated without destruction and other negative events with essential deformations. To prevent initial deviation from the form it necessary to remove preliminarily welding flash from the tube internal surface or use the instrument with enlarged angle of entry cone

  5. Mechanical properties, microstructure and micro-texture evolution for 1050AA deformed by equal channel angular pressing (ECAP) and post ECAP plane strain compression using two loading schemes

    International Nuclear Information System (INIS)

    Highlights: ? ECAP to four passes via route BC is combined with plane strain compression for 1050AA. ? Two loading schemes are employed in plane strain compression (PSC). ? Strain path change is employed to study microstructure and micro-texture. ? Prior texture to PSC influences the intensity of the developed rolling texture. ? Texture can be manipulated to produce a brass type texture in high SFE materials. -- Abstract: Electron back scattered diffraction (EBSD) was used to document the microstructure and microtexture developed due to cross deformation of commercial purity 1050 aluminum alloy. The material was first deformed in an equal channel angular pressing die (ECAP) to one up to four passes, via route Bc and then deformed in plane strain compression (PSC), in two different directions, to two axial true plastic strain values of 0.5 and 1.0. The study provides a documentation of the evolution of microstructure parameters namely; cell size, average misorientation angle, fraction of submicron cell size and fraction of high angle grain boundaries. These microstructure parameters were investigated on the plane normal to the loading direction in PSC (plane constituted by the rolling and transverse directions). These microstructure parameters were compared to those achieved due to the ECAP process only. The ideal rolling texture orientations are depicted and crystal orientation maps were generated. The spatial distribution of grains having these orientations are revealed through these maps. The fraction of the main texture components for a 15o spread around the specified orientations was experimentally calculated and a quantitative idea on the evolution of microtexture was also presented. Deformation path change was shown to be an effective tool for manipulating texture as well as microstructure.

  6. Shell structures and chaos in deformed nuclei and large metallic clusters

    CERN Document Server

    Heiss, W D; Radu, S; Heiss, W D; Nazmitdinov, R G; Radu, S

    1994-01-01

    A reflection-asymmetric deformed oscillator potential is analysed from the classical and quantum mechanical point of view. The connection between occurrence of shell structures and classical periodic orbits is studied using the ''removal of resonances method'' in a classical analysis. In this approximation, the effective single particle potential becomes separable and the frequencies of the classical trajectories are easily determined. It turns out that the winding numbers calculated in this way are in good agreement with the ones found from the corresponding quantum mechanical spectrum using the particle number dependence of the fluctuating part of the total energy. When the octupole term is switched on it is found that prolate shapes are stable against chaos whereas spherical and oblate cases become chaotic. An attempt is made to explain this difference in the quantum mechanical context by looking at the distribution of exceptional points which results from the matrix structure of the respective Hamiltonian...

  7. Significance of deformation mode in hot deformation

    Energy Technology Data Exchange (ETDEWEB)

    Davenport, S.B.; Todd, I.; Zwaag, S. van der [Netherlands Inst. for Metals Res., Delft (Netherlands)

    2000-07-01

    In order to study strain path effects, hot deformation tests must be carried out utilising different combinations of compressive, tensile and shear strains. However, before the results from these tests can be reliably interpreted, it is important to carry out deformations in simple tension, compression and torsion as a 'baseline'. Differences in deformation mode affect the deformed grain shape and grain boundary area. The slip systems activated during, for example, torsion and compression will also be different, this leads to differences in final textures and substructural morphology. The macroscopic consequence of these is that flow stress and recrystallisation kinetics are dependent on deformation mode. An important issue which needs to be addressed is whether the micro-/macro-structural response of a material to complex strain histories can be predicted using simple additive functions of the baseline data. This initial round of tests was conducted on an Al-Mg-Mn-Si alloy. (orig.)

  8. Transverse Radiation realized as Deformed Harmonic Oscillators

    CERN Document Server

    Swamy, P N

    2004-01-01

    We present a theory of quantized radiation fields described in terms of q-deformed harmonic oscillators. The creation and annihilation operators satisfy deformed commutation relations and the Fock space of states is constructed in this formalism in terms of basic numbers familiar from the theory of quantum groups. Expressions for the Hamiltonian and momentum arising from deformed Heisenberg relations are obtained and their consequences investigated. The energy momentum properties of the vacuum state are studied. The commutation relation for the fields is shown to involve polarization sums more intricate than those encountered in standard quantum electrodynamics, thus requiring explicit representations of polarization vectors. The electric field commutation rules are investigated under simplifying assumptions of polarization states, and the commutator in the deformed theory in this case is shown to be reminiscent of the coordinate-momentum uncertainty relation in the theory of q-deformed quantum oscillators.

  9. Deformed Galilei symmetry

    CERN Document Server

    Kosinski, P

    1998-01-01

    A particular deformation of central extended Galilei group is considered. It is shown that the deformation influences the rules of constructing the composed systems while one particle states remain basically unaffected. In particular the mass appeared to be non additive.

  10. Deformed Frogs in Minnesota

    Science.gov (United States)

    This Web site includes background information on the problem and exploration of deformed frogs in Minnesota, where deformed frogs were first discovered by a group of school children in 1995. The site includes several Adobe Acrobat (.pdf) downloadable reports and fact sheets on deformed frogs and the investigation of them, along with a live frog cam where visitors can observe an aquarium of deformed frogs.

  11. Deformable Random Dot Markers

    OpenAIRE

    Uchiyama, H.; Marchand, E.

    2011-01-01

    We extend planar fiducial markers using random dots 8 to non- rigidly deformable markers. Because the recognition and tracking of random dot markers are based on keypoint matching, we can estimate the deformation of the markers with nonrigid surface de- tection from keypoint correspondences. First, the initial pose of the markers is computed from a homography with RANSAC as a planar detection. Second, deformations are estimated from the min- imization of a cost function for deformable surface...

  12. The deformation of bcc alloys

    OpenAIRE

    Wood, M. I.; Taylor, G.; Taylor, Dr G.

    1982-01-01

    ?A detailed study has been made of thermally activated glide between 373 K and 20 K for UHV annealed single crystals of two Nb based substitutional alloy systems containing 1-16 at.%Mo or 4 - 60 at.%Ta, in conjunction with a study of the deformation of UHV annealed single crystals of Nb between 4.2 K and 77 K. Whilst the addition of Ta had only a small effect on the properties of Nb as measured by activation ...

  13. Deformation Behavior of Human Dentin under Uniaxial Compression

    OpenAIRE

    Dmitry Zaytsev; Sergey Grigoriev; Peter Panfilov

    2012-01-01

    Deformation behavior of a human dentin under compression including size and rate effects is studied. No difference between mechanical properties of crown and root dentin is found. It is mechanically isotropic high elastic and strong hard tissue, which demonstrates considerable plasticity and ability to suppress a crack growth. Mechanical properties of dentin depend on a shape of samples and a deformation rate.

  14. On peculiarities of plastic behaviour of metal under deformation

    International Nuclear Information System (INIS)

    Processes occuring in metals under deformation are analyzed. A new approach to analysis of deformation processes is suggested coming from ideas of a limiting state of substance under deformation. Tension diagrams for ingot iron and steels 20, 45, 40X have been studied using the proposed procedure. A linear dependence is obtained for the deformation logarithm versus the inverse value of true deformation stresses. The strain limit and modulus of plastic deformation are shown to be the most important characteristics of plastic deformation. It is stated that enhanced values of the strain limit and modulus of plastic deformation are attributed to higher strength properties of materials under study. The revealed regularities make it possible to predict ways of futher increase in strength and plastic characteristics of meterials and to design stresses and strains atising in articles in service

  15. Electrical conductivity and mechanical properties of Cu-0.7wt% Cr and Cu-1.0wt% Cr alloys processed by severe plastic deformation

    Science.gov (United States)

    Kommel, L.; Pokatilov, A.

    2014-08-01

    As-cast Cu-0.7wt% Cr and Cu-1.0wt% Cr alloys were subjected to equal-channel angular pressing (ECAP), hard cyclic viscoplastic (HCV) deformation and post deformation heat treatment for receiving an ultrafine grained material with a combination of high strength, good wear resistance and high electric conductivity. Samples from Cu-0.7wt% Cr alloy were processed up to six passes and Cu-1wt% Cr alloy samples were processed up to four passes of ECAP via Bc route. HCV deformation of samples was conducted by frequency of 0.5 Hz for 20 cycles at tension-compression strain amplitudes of +/-0.05%, +/-0.1%, +/-0.5%, +/-1% and +/-1.5%, respectively. During HCV deformation, as-cast Cu-0./wt% Cr alloy show fully viscoelastic behavior at strain/stress amplitude of +/-0.05% while ECAP processed material show the same behavior at strain amplitude of +/-0.1%. The Young modulus was increased from ~120 GPa up to ~150 GPa. The results illustrated that specific volume wear decrease with increasing of hardness but the measured coefficient of friction (COF ~ 0.6) was approximately the same for all samples at the end of wear testing. The hardness after ECAP for 6 passes by Bc route was 192HV0.1 and electric conduction 74.16% IACS, respectively. By this the as-cast Cu-0./wt% Cr alloy (heat treated at 1000 °C for 2h) has microhardness ~70HV0.1 and electrical conductivity of ~40% IACS. During aging at the temperatures in the interval of 250-550 °C for 1h the hardness and electrical conductivity were stabilized to mean values of 120+/-5HV0.1 and to 93.4+/-0.3% IACS, respectively. The hardness and electric conductivity took decrease by temperature increase over ~550 °C, respectively. The results of present experimental investigation show that UFG Cu- 0.7wt% Cr alloy with compare to Cu-1.0% Cr alloy is a highly electrical conductive and high temperature wear resistant material for using in electrical industry.

  16. Deformation of C15 Laves phase alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chu, F.; Pope, D.P.

    1995-12-31

    Details of the structure and previous work on the deformation of C Laves phases are reviewed. The phase diagram of the Hf-V-Nb system, some metallurgical and physical properties, mechanical behavior, and the deformation mechanisms of HfV{sub 2}+Nb (CI5 HfV{sub 2}+Nb and V-rich bcc solution) are presented based on our previous work. Theoretical approaches to understanding the results of these studies are discussed.

  17. Analysis of factors regulating erythrocyte deformability.

    OpenAIRE

    Mohandas, N.; Clark, M. R.; Jacobs, M. S.; Shohet, S. B.

    1980-01-01

    Using a laser diffraction technique, we have studied factors that influence the deformability of erythrocytes. Variations in suspending medium osmolality and applied shear stress were employed to isolate the individual contributions to whole cell deformability of internal viscosity, surface area-to-volume ratio, and viscoelastic properties of the membrane. An experimental system was devised in which normal cells were modified in vitro to induce specific alterations in each factor. Measurement...

  18. Influence of hot plastic deformation on phase composition, microstructure and superconductive properties of Y0.9(Ca0.1)Ba2Cu4O8 ceramics

    International Nuclear Information System (INIS)

    The influence of hot plastic deformation by extrusion on texture, microstructure and phase composition of Y(Ca)124 ceramics has been investigated. Extrusion has been carried out in air at T=800 and 850 degrees C. The initial material was produced by HIP at T = 1010 degrees C, P = 1800 bar, ? =4 hours and contained a large amount of impurities such as Y2BaCuO5, BaCuO2, CuO, as well as intermediate phases of Y(Ca)xBayCuzO type with superfluous Y. The volume fraction of Y(Ca)124 was only 46%. During hot extrusion the Y(Ca)124 phase did not decompose, but on the contrary, additional synthesis and significant compositional homogenization of the ceramic took place. The volume fraction of Y(Ca)124 in extruded samples reached 85%. Microstructural changes, taking place in the process of Y(Ca)124 deformation, are the following: (i) intensive microstructure refinement occurs as a result of dynamic recrystallization; (ii) radial texture is formed. (author)

  19. Deformations in quantum mechanics

    International Nuclear Information System (INIS)

    We consider deformations of quantum mechanical objects, and use the novel construction of warped convolutions for deformation. It turns out that through the deformation we are able to obtain several quantum mechanical effects where electromagnetic fields play a role. We understand the magnetic field as an object which is the outcome of strict mathematical deformation. Furthermore, we are able to obtain all magnetic fields by using this method of deformation. The results are used in quantum field theory to obtain an effective quantum plane.

  20. Deformations in quantum physics

    International Nuclear Information System (INIS)

    We consider deformations of quantum mechanical objects, and use the novel construction of warped convolutions for deformation. It turns out that through the deformation we are able to obtain several quantum mechanical effects where electromagnetic fields play a role. We understand the magnetic field as an object which is the outcome of strict mathematical deformation. Furthermore, we are able to obtain all magnetic fields by using this method of deformation. The results are used in quantum field theory to obtain an effective quantum plane.

  1. Effect of precipitates on long-term creep deformation properties of P92 and P122 type advanced ferritic steels for USC power plants

    International Nuclear Information System (INIS)

    Long-term creep rupture strengths and the microstructural stability of ASME P92 and P122 pipes have been studied using creep testing at the temperatures from 550 to 700 deg. C and detailed scanning transmission electron microscopy. Creep rupture strength of P92 is found to be more stable than that of P122 at temperatures over 600 deg. C, which is mainly due to the difference in their Cr content. P122 type model steel with reduced Cr content, 9%Cr, has been prepared to explore the effect of Cr on the stability of MX and formation of Z-phase during creep deformation. MX in 9%Cr steel is found to be stable even after prolonged exposure at 650 deg. C, while Cr and Fe concentration to MX without marked coarsening has been observed in 10.5%Cr steel after aging for 10,000 h at 650 deg. C. This seems to lead to the transition of MX carbonitride into the Z-phase after aging for 23,000 h, which requires ordering in a M2N lattice to achieve a tetragonal Z-phase to be stable. Creep deformation behavior in the transient creep region of the steels is almost same up to about 7000 h, while in the acceleration creep region the creep rate of 10.5%Cr steel becomes much faster than that of 9%Cr steel, resulting in shorter rupture life. It is obvious that the creep rupture strength degradation starts prior to the formation of Z-phase in 10.5%Cr steel. It is thus concluded that Z-phase is not a necessary factor for degradation of creep rupture strength but the instability of theupture strength but the instability of the fine precipitates such as Cr2(C, N) caused by the compositions change like Cr supply to MX carbonitride is more essential.

  2. Decoupling, band forking, and deformation

    International Nuclear Information System (INIS)

    From extensive in-beam ?-ray studies of odd-mass and odd-odd Re isotopes, the authors have elucidated properties of many decoupled (open-quotes Kclose quotes = 1/2) and doubly decoupled (1/2 circle-times 1/2) bands. Such ?I = 2 bands are the most intensely populated in a variety of heavy-ion induced reactions. They suffer extreme coriolis distortions and exhibit complex alignment patterns, but from them much can be deduced about the deformation-driving properties of the p and n states involved. In several odd-mass isotopes, and most clearly in 175Re, a second, weakly populated ?I = 2 band feeds into the decoupled band around I = 17/2-. At times this band has been interpreted as a 1/2+[660] band, but such is unlikely because of the necessarily slow, hindered E1 interband transitions required. The authors find it more likely that this band is an alternate, higher-deformation backbending sequence associated with the decoupled band itself-this would account for its similar population patterns in reactions involving projectiles with widely differing masses. Multiple decouplings of this type may also lead to extreme deformations, perhaps even superdeformation

  3. Greenland Analogue Project - Hydraulic properties of deformation zones and fracture domains at Forsmark, Laxemar and Olkiluoto for usage together with Geomodel version 1

    International Nuclear Information System (INIS)

    The database of the GAP site is under development. In order to meet the data needs of the different modelling teams working with groundwater flow modelling it has been decided to compile trial data sets comprising structural-hydraulic properties suitable for flow modelling on different scales. The properties provided in this report are based on data and groundwater flow modelling studies conducted for three sites located in the Fennoscandian Shield, two of which are studied by SKB, Forsmark and Laxemar, and one by Posiva, Olkiluoto. The provided hydraulic properties provided here are simplified to facilitate a readily usage together with the GAP Geomodel version 1

  4. Greenland Analogue Project - Hydraulic properties of deformation zones and fracture domains at Forsmark, Laxemar and Olkiluoto for usage together with Geomodel version 1

    Energy Technology Data Exchange (ETDEWEB)

    Follin, Sven (SF GeoLogic AB (Sweden)); Stigsson, Martin (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)); Rhen, Ingvar (Sweco Environment AB (Sweden)); Engstroem, Jon (Geologian tutkimuskeskus (Finland)); Klint, Knut Erik (De Nationale Geologiske Undersoegelser for Danmark og Groenland (Denmark))

    2011-05-15

    The database of the GAP site is under development. In order to meet the data needs of the different modelling teams working with groundwater flow modelling it has been decided to compile trial data sets comprising structural-hydraulic properties suitable for flow modelling on different scales. The properties provided in this report are based on data and groundwater flow modelling studies conducted for three sites located in the Fennoscandian Shield, two of which are studied by SKB, Forsmark and Laxemar, and one by Posiva, Olkiluoto. The provided hydraulic properties provided here are simplified to facilitate a readily usage together with the GAP Geomodel version 1.

  5. Determination of the B(E3,0$^{+}$->3$^{-}$) strength in the octupole correlated nuclei $^{142,144}$Ba using Coulomb excitation

    CERN Multimedia

    We propose to exploit the unique capability of ISOLDE to provide intense post-accelerated $^{142}$Ba and $^{144}$Ba ion beams from the HIE-ISOLDE facility to enable the Coulomb excitation of the first 3- state in these nuclei. By measuring the $\\gamma$-ray yields of the E1 decays from the 3- state using the MINIBALL array, we can obtain the interesting transition matrix element. The results will give quantitative information about octupole correlations in these nuclei. We require 33 shifts to fulfil the aims of the experiment.

  6. Determination of the B(E3,0$^{+} \\rightarrow$ 3$^{-}$) strength in the octupole correlated nucleus $^{144}$Ba using Coulomb excitation

    CERN Multimedia

    We propose to exploit the unique capability of ISOLDE to provide intense post-accelerated $^{144}$Ba ion beams from the REX facility to enable the Coulomb excitation of the first 3 $^{-}$ state in this nucleus. By measuring the $\\gamma$-ray yields of the E1 decay connecting the 3$^{-}$ and 2$^{+}$ states using the MINIBALL array, we can obtain the interesting transition matrix element. The result will give quantitative information about octupole correlations in this nucleus. We require 27 shifts to fulfil the aims of the experiment. Requested shifts:

  7. An algebraic q-deformed form for shape-invariant systems

    Energy Technology Data Exchange (ETDEWEB)

    Aleixo, A N F [Instituto de FIsica, Universidade Federal do Rio de Janeiro, RJ (Brazil); Balantekin, A B [Department of Physics, University of Wisconsin, Madison, WI 53706, USA (United States); Ribeiro, M A Candido [Departamento de FIsica, Instituto de Biociencias, Letras e Ciencias Exatas UNESP, Sao Jose do Rio Preto, SP (Brazil)

    2003-11-21

    A quantum deformed theory applicable to all shape-invariant bound-state systems is introduced by defining q-deformed ladder operators. We show that these new ladder operators satisfy new q-deformed commutation relations. In this context we construct an alternative q-deformed model that preserves the shape-invariance property presented by the primary system. q-deformed generalizations of Morse, Scarf and Coulomb potentials are given as examples.

  8. An Algebraic q-Deformed Form for Shape-Invariant Systems

    CERN Document Server

    Aleixo, A N F; Ribeiro, M A C

    2003-01-01

    A quantum deformed theory applicable to all shape-invariant bound-state systems is introduced by defining q-deformed ladder operators. We show these new ladder operators satisfy new q-deformed commutation relations. In this context we construct an alternative q-deformed model that preserve the shape-invariance property presented by primary system. q-deformed generalizations of Morse, Scarf, and Coulomb potentials are given as examples.

  9. An algebraic q-deformed form for shape-invariant systems

    International Nuclear Information System (INIS)

    A quantum deformed theory applicable to all shape-invariant bound-state systems is introduced by defining q-deformed ladder operators. We show that these new ladder operators satisfy new q-deformed commutation relations. In this context we construct an alternative q-deformed model that preserves the shape-invariance property presented by the primary system. q-deformed generalizations of Morse, Scarf and Coulomb potentials are given as examples

  10. Relativistic description of deformed nuclei

    International Nuclear Information System (INIS)

    The author has shown that relativistic Hartree calculations using parameters that have been fit to the properties of nuclear matter can provide a good description of both spherical and axially deformed nuclei. The quantitative agreement with experiment is equivalent to that which was obtained in non-relativistic calculations using Skyrme interactions. The equilibrium deformation is strongly correlated with the size of the spin-orbit splitting, and that parameter sets which give roughly the correct value for this splitting provide the best agreement with the quadrupole moments in the s-d shell. Finally, for closed shell +/- 1 nuclei, it was shown that the self-consistent calculations are able to reproduce the experimental magnetic moments. This was not possible in relativistic calculations which include only the effects of the valence orbital

  11. Estudo da influência da deformação e do envelhecimento nas propriedades mecânicas da superliga de níquel X-750 / Study of the influence of deformation and aging on the mechanical properties of the nickel superalloy X-750

    Scientific Electronic Library Online (English)

    G. R. X., Souza; S. B., Gabriel; A. F., Ribeiro; L. H. de, Almeida.

    Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A superliga de níquel X-750 pertence a classe das ligas níquel-cromo-alumínio-titânio e é indicada para aplicações em altas temperaturas e ambientes corrosivos. Entre outras aplicações é utilizada para a fabricação de molas helicoidais operando como componente estrutural de reatores nucleares. A pre [...] sença do titânio em teores da ordem de 2,5% em peso confere à liga elevada resistência mecânica pelo mecanismo de endurecimento por precipitação da fase coerente ?'. Por outro lado o controle das propriedades mecânicas finais é fortemente dependente do grau de encruamento prévio ao tratamento térmico de envelhecimento. Segundo a norma AMS 5698G, o fio da superliga X-750 a ser utilizado na fabricação de molas helicoidais deve ser submetido a um tratamento térmico de solubilização e em seguida deve ser reduzido a frio de aproximadamente 15% de sua área. Após a redução, a mola é conformada e submetida a um tratamento de precipitação e resfriada ao ar. No entanto, não se encontra na literatura cientifica dados suficientes para caracterizar as propriedades mecânicas, particularmente os níveis de resistência, em função dos mecanismos de endurecimento atuantes. O presente trabalho teve como objetivo estudar diferentes rotas de processamento para se obter fios da liga X-750 de forma a maximizar as propriedades para a aplicação na fabricação de molas helicoidais em função do grau de deformação do último passe de trefilação. As diferentes etapas de processamento foram caracterizadas por microscopia ótica e eletrônica de varredura e as propriedades mecânicas por ensaio de dureza Vickers e tração uniaxial. Observou-se, como esperado, que o ganho de resistência devido à deformação foi proporcional ao grau de deformação aplicado. Por outro lado, entretanto, o ganho de resistência devido ao tratamento térmico de envelhecimento é reduzida com o aumento do grau de deformação, ocasionando em uma tensão limite de escoamento cada vez mais dependente do grau de encruamento e, dessa forma, em prejuízo de tenacidade. Abstract in english The nickel base superalloy X-750 is a nickel-chromium-titanium-aluminum alloy that is suitable for high temperature applications and corrosive environments. Among others applications, it can be used in helical springs manufacturing acting as a structural component in nuclear reactors. The titanium p [...] resence at levels of about 2.5wt% gives the alloy high strength by precipitation of the coherent phase ?'. According to the standard AMS 5698G, the wire of X-750 alloy to be used in helical springs manufacturing must be subjected to a solution heat treatment and then be cold reduced by approximately 15% of its area. After the reduction, the spring is shaped as well as precipitation heat treated and air cooling. However, there is not enough data in the scientific literature to characterize the mechanical properties, particularly resistance levels as a function of these hardening mechanisms. This paper aimed to study different processing routes to obtain wires of X-750 alloy in order to maximize the properties for helical springs applications according to the last pass drawing deformation degree. The different processing steps were characterized by optical microscopy and scanning electron microscopy and mechanical properties by Vickers hardness and tensile. As expected, the resistance gain due to deformation was proportional to the deformation degree applied. On the other hand, however, the aging heat treatment contribution is reduced with the deformation degree increasing, resulting in a yield stress increasingly dependent on the hardening degree.

  12. Triaxially deformed relativistic point-coupling model for $\\Lambda$ hypernuclei: a quantitative analysis of hyperon impurity effect on nuclear collective properties

    CERN Document Server

    Xue, W X; Hagino, K; Li, Z P; Mei, H; Tanimura, Y

    2014-01-01

    The impurity effect of hyperon on atomic nuclei has received a renewed interest in nuclear physics since the first experimental observation of appreciable reduction of $E2$ transition strength in low-lying states of hypernucleus $^{7}_\\Lambda$Li. Many more data on low-lying states of $\\Lambda$ hypernuclei will be measured soon for $sd$-shell nuclei, providing good opportunities to study the $\\Lambda$ impurity effect on nuclear low-energy excitations. We carry out a quantitative analysis of $\\Lambda$ hyperon impurity effect on the low-lying states of $sd$-shell nuclei at the beyond-mean-field level based on a relativistic point-coupling energy density functional (EDF), considering that the $\\Lambda$ hyperon is injected into the lowest positive-parity ($\\Lambda_s$) and negative-parity ($\\Lambda_p$) states. We adopt a triaxially deformed relativistic mean-field (RMF) approach for hypernuclei and calculate the $\\Lambda$ binding energies of hypernuclei as well as the potential energy surfaces (PESs) in $(\\beta, \\g...

  13. Stationary stage of hot deformation and superplasticity of aluminium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Vainblat, Y.; Davydov, V.; Sharshagin, N. [All-Union Inst. of Light Alloys, Moscow (Russian Federation)

    2000-07-01

    The method of obtaining of samples with a large (unlimited) degree of deformation is developed by packet compression of flat samples under the scheme of plane strain deformation, with welding layers under the joint deforming. The properties of samples with stationary structure investigated, when subgrains and grains have constant sizes. Established, that superplasticity realized only at transient stage from one stationary stage to another. (orig.)

  14. Deformation of 126Ce

    International Nuclear Information System (INIS)

    The gamma decays of excited states in the nucleus 126Ce have been identified in a study of the 92Mo(40Ca,?2p)126Ce reaction at 150-200 MeV bombarding energy using multiple particle-gamma coincidence techniques. Measurements were made of gamma-ray angular distributions and production cross sections as a function of energy. The lifetimes of the lowest states in the ground state band of 126Ce were measured using the recoil distance method. The first excited state was found to have a meanlife of ?m = 949±53 ps, which is consistent with a ground state quadrupole deformation of ?2 = 0.28±0.01 assuming axial symmetry and a uniform charge distribution. In the ground state rotational sequence a backbend is observed at ??C ? 0.32 MeV. This appears to be due to the alignment of h11/2 protons. These properties are compared with the results of potential energy surface and cranked shell model calculations and are assessed in the context of the systematic behaviour of even-even nuclei in this mass region. (orig.)

  15. Strengthening of HSLA steels by cool deformation

    International Nuclear Information System (INIS)

    In microalloyed steels, the refinement of ferrite grains together with a controlled amount of precipitation has key roles in the mechanical properties improvement. Applying small amounts of deformation, at very low hot working temperatures (i.e. coiling temperature), in the ferrite region (i.e. cool deformation) has an appreciable strengthening effect via controlling the final microstructure of the steel. One of the microstructural effects is thought to be the much finer and more uniformly dispersed precipitates in the steel matrix. In the present study, the effects of Nb and Cu on mechanical properties and corresponding microstructures in steels with different levels of cool deformation are investigated. The mechanical properties of the samples were determined using the shear punch test and the microstructure was examined by scanning and transmission electron microscopy. Thermodynamic simulations with FactSage were done to further analyze the precipitation possibility of different elements. It has been found that these alloying elements respond very well to cool deformation, with the strength being highest in steels containing both Nb and Cu. However, a cool deformation effect in the non-Nb and Cu bearing steel is also observed. In all cases, it was confirmed that precipitation plays a key role in the effect of cool deformation, with much of the precipitation taking place dynamically. Nevertheless, static processes also seem to have a measurable effect on room temperto have a measurable effect on room temperature properties. Even low amounts of copper (e.g. ?0.4 wt%) can contribute to strengthening of the steel. The Cu addition is found to affect the mechanical properties by affecting the precipitation and growth of Nb compounds.

  16. Results and perspectives of invesgtigations at the accelerators in LNR of JINR of high-energy ion irradiation influence on structure, deformational and strength metal and crystal properties

    International Nuclear Information System (INIS)

    The review on radiation material test in LNR of JINR at heavy ion accelerators are given. The description of experimental methods, which can permit to study different material properties at heavy ion irradiation is presented. The results on different crystals, metals and alloy investigations, irradiated by ions with energies from 1 to 10 MeV/nucleon are considered

  17. Deformation of zirconium polycrystals

    International Nuclear Information System (INIS)

    Polycrystals of Zr have been deformed in tension at temperatures between 77 and 900K. The yield stress and the activation volume are dependent on temperature. Dislocation structure in specimens deformed at 77 and 500K is reported. Possible mechanisms explaining the temperature dependence of the yield stress are discussed

  18. Deformation of zirconium polycrystals

    International Nuclear Information System (INIS)

    Polycrystals of Zr have been deformed in tension at temperatures between 77 and 900K. The yield stress and the activation volume are dependent on temperature. Dislocation structure in specimens deformed at 77 and 500K is reported. Possible mechanisms explaining the temperature dependence of the yield stress are discussed. (author)

  19. Cu/Nb nano-composite wires processed by severe plastic deformation for applications in high pulsed magnets: effects of the multi-scale microstructure on the mechanical properties

    International Nuclear Information System (INIS)

    Copper-based high strength and high electrical conductivity nano-composite wires reinforced by Nb nano-tubes are prepared by severe plastic deformation, applied with an Accumulative Drawing and Bundling process (ADB), for the windings of high pulsed magnets. The ADB process leads to a multi-scale Cu matrix containing up to N = 854 (52.2.106) continuous parallel Nb tubes with diameter down to few tens nano-meters. After heavy strain, the Nb nano-tubes exhibit a homogeneous microstructure with grain size below 100 nm. The Cu matrix presents a multi-scale microstructure with multi-modal grain size distribution from the micrometer to the nano-meter range. The use of complementary characterization techniques at the microscopic and macroscopic level (in-situ tensile tests in the TEM, nano-indentation, in-situ tensile tests under high energy synchrotron beam) shed light on the interest of the multi-scale nature of the microstructure to achieve extreme mechanical properties, therefore allowing for design guidelines to further improve these properties. (authors)

  20. Quantum Symmetries and Marginal Deformations

    CERN Document Server

    Mansson, Teresia

    2008-01-01

    We study the symmetries of the N=1 exactly marginal deformations of N=4 Super Yang-Mills theory. For generic values of the parameters, these deformations are known to break the SU(3) part of the R-symmetry group down to a discrete subgroup. However, a closer look from the perspective of quantum groups reveals that the Lagrangian is in fact invariant under a certain Hopf algebra which is a non-standard quantum deformation of the algebra of functions on SU(3). Our discussion is motivated by the desire to better understand why these theories have significant differences from N=4 SYM regarding the planar integrability (or rather lack thereof) of the spin chains encoding their spectrum. However, our construction works at the level of the classical Lagrangian, without relying on the language of spin chains. Our approach might eventually provide a better understanding of the finiteness properties of these theories as well as help in the construction of their AdS/CFT duals.

  1. Dislocation Dynamics During Plastic Deformation

    CERN Document Server

    Messerschmidt, Ulrich

    2010-01-01

    The book gives an overview of the dynamic behavior of dislocations and its relation to plastic deformation. It introduces the general properties of dislocations and treats the dislocation dynamics in some detail. Finally, examples are described of the processes in different classes of materials, i.e. semiconductors, ceramics, metals, intermetallic materials, and quasicrystals. The processes are illustrated by many electron micrographs of dislocations under stress and by video clips taken during in situ straining experiments in a high-voltage electron microscope showing moving dislocations. Thus, the users of the book also obtain an immediate impression and understanding of dislocation dynamics.

  2. Deformation retracts of Stein spaces

    International Nuclear Information System (INIS)

    If X is an n-dimensional Stein space, it was proved that X has the homotopy type of a CW-complex of dimension?n and in the algebraic case this was proved with the additional conclusion that the CW-complex is finite. In this paper the authors give an answer to the question if there exists a subset Q of X with the same topological properties as X, for instance Q is a strong deformation retract of X, and Q is a CW-complex of dimension?n. 15 refs

  3. Cosmetic and Functional Nasal Deformities

    Science.gov (United States)

    ... nasal complaints. Nasal deformity can be categorized as “cosmetic” or “functional.” Cosmetic deformity of the nose results in a less ... taste , nose bleeds and/or recurrent sinusitis . A cosmetic or functional nasal deformity may occur secondary to ...

  4. On the propagation of a quasi-static disturbance in a heterogeneous, deformable, and porous medium with pressure-dependent properties

    Energy Technology Data Exchange (ETDEWEB)

    Vasco, D.W.

    2011-10-01

    Using an asymptotic technique, valid when the medium properties are smoothly-varying, I derive a semi-analytic expression for the propagation velocity of a quasi-static disturbance traveling within a nonlinear-elastic porous medium. The phase, a function related to the propagation time, depends upon the properties of the medium, including the pressure-sensitivities of the medium parameters, and on pressure and displacement amplitude changes. Thus, the propagation velocity of a disturbance depends upon its amplitude, as might be expected for a nonlinear process. As a check, the expression for the phase function is evaluated for a poroelastic medium, when the material properties do not depend upon the fluid pressure. In that case, the travel time estimates agree with conventional analytic estimates, and with values calculated using a numerical simulator. For a medium with pressure-dependent permeability I find general agreement between the semi-analytic estimates and estimates from a numerical simulation. In this case the pressure amplitude changes are obtained from the numerical simulator.

  5. Deformation Investigation of Weld Based Rapid Prototyping

    Directory of Open Access Journals (Sweden)

    Abdul Samee

    2014-05-01

    Full Text Available This study investigates the deformation produced in the weld-based prototype and to optimize the welding parameters to minimize this deformation. Weld-based prototyping is a method to produce form-fit and near-net-shape or net shape prototypes. However, the large amount of heat exposure for the substrate plate and for previously built layers is one of the limitations of weld based prototyping. This causes high temperature gradient which results in deformation, residual stresses, warpage and poor surface quality. In this study a part is made by using welding by incremental layer buildup method. This yielded anisotropic material properties in the part with the non-homogeneous structure and porosity. In present study above mentioned problems were minimized by proper selection and optimizing the deposition parameters such as inter-pass cooling time, heat sink size, deposition speed, applying mechanical constraints and preheating. For analysis of present weld based prototype, experimental approach is adopted. In such developments, the phenomenon of deformation is very crucial to control. In this study a focus has been made on investigation of deformation produced and the parameters effecting this deformation.

  6. Intermetallic alloys: Deformation, mechanical and fracture behaviour

    International Nuclear Information System (INIS)

    The state of the art in intermetallic alloys development with particular emphasis on deformation, mechanical and fracture behaviour is documented. This review paper is prepared to lay the ground stones for a future work on mechanical property characterization and fracture behaviour of intermetallic alloys at GKSS. (orig.)

  7. Marginal Polytope of a Deformed Exponential Family

    CERN Document Server

    Pistone, Giovanni

    2011-01-01

    A deformed logarithm function called $q$-logarithm has received considerable attention by physicist after its introduction by C. Tsallis. J. Naudts has proposed a generalization called $\\phi$-logarithm and he has derived the basic properties of $\\phi$-exponential families. In this paper we study the related notion of marginal polytope in the case of a finite state space.

  8. Gardner's deformations of the Boussinesq equations

    CERN Document Server

    Karasu, A; Karasu, Atalay; Kiselev, Arthemy V.

    2006-01-01

    Using the algebraic method of Gardner's deformations for completely integrable systems, we construct the recurrence relations for densities of the Hamiltonians for the Boussinesq and the Kaup-Boussinesq equations. By extending the Magri schemes for these systems, we obtain new integrable equations adjoint with respect to the initial ones and describe their Hamiltonian structures and symmetry properties.

  9. Elastic-plastic Contact of a Deformable Sphere Against a Rigid Flat for Varying Material Properties Under Full Stick Contact Condition

    Directory of Open Access Journals (Sweden)

    B. Chatterjee

    2011-12-01

    Full Text Available The present study considers finite element based contact analysis of an elastic-plastic axisymmetric hemisphere using ANSYS to study the effect of material properties under full stick contact condition. Results are compared with previous elastic-plastic models for perfect slip and full stick contact conditions. It is found that materials with modulus of elasticity to yield strength (E/Y ratio less than and greater than 300 show strikingly different contact behavior. When E/Y ratio is less than 300, contact load increases with the increase in modulus of elasticity whereas in elastic-plastic range, contact load decreases with the increase in yield strength.

  10. Deformations of Koszul Artin-Schelter Gorenstein algebras

    OpenAIRE

    He, Jiwei; Oystaeyen, Fred; Zhang, Yinhuo

    2013-01-01

    We compute the Nakayama automorphism of a Poincare-Birkhoff-Witt (PBW)-deformation of a Koszul Artin-Schelter (AS) Gorenstein algebra of finite global dimension, and give a criterion for an augmented PBW-deformation of a Koszul Calabi-Yau algebra to be Calabi-Yau. The relations between the Calabi-Yau property of augmented PBW-deformations and that of non-augmented cases are discussed. The Nakayama automorphisms of PBW-deformations of Koszul AS-Gorenstein algebras of global dimensions 2 and 3 ...

  11. Optical Deformability as New Diagnostic Cell Marker

    Science.gov (United States)

    Guck, Jochen; Lincoln, Bryan; Schinkinger, Stefan; Wottawah, Falk; Moore, Samantha; Ananthakrishnan, Revathi; Kas, Josef

    2002-03-01

    The optical stretcher is a novel laser tool that can deform individual cells in rapid succession. When a cell is trapped between two counterpropagating laser beams the optically induced surface forces stretch the cell along the laser axis. The degree of stretching depends on the optical properties, which determine the forces, as well as the mechanical properties, which govern the response of the cell to the forces. Our results show that different cells can be distinguished based on their optical deformability, which naturally suggests using the optical deformability of cells as a novel cell marker. Many diseases are reflected in an altered cytoskeleton, which leads to a different optical deformability. An important example is the malignant transformation of cells, which is accompanied by a decrease in cytoskeletal integrity and, consequently, cell elasticity. Using optical deformability as cell marker holds the promise of earlier detection and improved diagnosis of cancer. In this context, the optical stretcher can be used as a diagnostic device to detect and sort abnormal cells. Future applications in the study of the normal differentiation of cells from stem cells to mature cells are envisioned.

  12. Investigation of structure and properties of the Nb rods manufactured by different deformation and heat treatment regimes in mass production conditions for the Nb3Sn strands

    International Nuclear Information System (INIS)

    From 2009 the mass production of the Nb3Sn strands for ITER with the yield of several tens of tons per year operates at JSC Chepetsky Mechanical Plant (Glazov, Russia). In order to enhance the stability of output characteristics of the produced Nb3Sn strands, to increase the Nb filaments dimensional homogeneity the manufacture regimes improvement of the used semiproducts such as Nb rods intended for the superconducting filaments formation in the finished strands has been carried out. In the work the investigations of the Nb rheological behavior, the influence of heat treatment in the wide temperature range from 700 to 1300 °C on the predeformed Nb rods structure and mechanical properties have been performed. Different production routes of the Nb rods, including such operations like forging, extrusion and drawing combined with the recrystallization annealings, were used. Composite Nb3Sn strands have been produced and their electrophysical properties have been tested. For the first time influence of the niobium rods manufacture regimes on the current carrying capacity of the industrial Nb3Sn strands has been investigated

  13. The alloying element dependence of the local lattice deformation and the elastic properties of Ni3Al: A molecular dynamics simulation

    International Nuclear Information System (INIS)

    Molecular dynamics (MD) together with the modified analytical embedded atom method (MAEAM) is employed to study the alloying elements (Re, Ru, Co, and Ta) dependence of the elastic properties of L12-Ni3Al. The investigations indicate that the calculated elastic properties of Ni3Al are in reasonable agreement with the previous results. The substituting formation energies of the alloying elements in Ni3Al are calculated to determine the site preference. It is found out that Re, Ru, and Ta atoms prefer to occupy the Al sites, and the Co atom prefers to occupy the Ni site. Based on Re, Ru, and Ta substituting the 1st, 2nd, 3rd, and 4th nearest-neighbor atoms, we ascertain that the substituting manners of these alloying elements have a decisive effect on the bulk modulus and the local crystal lattice of Ni3Al. Moreover, for Re, the bonding interaction plays a predominant role in the improvement in the bulk modulus of Ni3Al, whereas the size effect of Ru and Ta on the improvement in the bulk modulus is more obvious. Finally, the potential reasons of which the alloying elements enhance the bulk modulus are discussed in details

  14. Anisotropic deformation response of single protein molecules

    OpenAIRE

    Dietz, Hendrik; Berkemeier, Felix; Bertz, Morten; Rief, Matthias

    2006-01-01

    Single-molecule methods have given experimental access to the mechanical properties of single protein molecules. So far, access has been limited to mostly one spatial direction of force application. Here, we report single-molecule experiments that explore the mechanical properties of a folded protein structure in precisely controlled directions by applying force to selected amino acid pairs. We investigated the deformation response of GFP in five selected directions. We found fracture forces ...

  15. Is the nucleon deformed ?

    International Nuclear Information System (INIS)

    A property of Quantum Chromodynamics (QCD) which should be included into effective models describing QCD at low energies is chiral symmetry. It is conserved if one assumes that the quark masses are zero. This symmetry is spontaneously broken, which leads to constituent quark and as the Goldstone Boson one obtains the pion and its chiral partner, the ? meson. We use the linear ? model which has, compared to the nonlinear one, the advantage that one treats pions and ? mesons not only on the chiral cycle, but allows also fluctuations around it. The scale of this fluctuations is the ? meson mass. If one eliminates gluons in second order, one obtains 'Tuebingen chiral quark model' with effective gluon exchange between the quarks and with pions and ? mesons. A confinement potential is added. With this model we describe the photo and electro-excitation of the nucleon into the delta resonance and the decay of this resonance into a nucleon and a pion. The angular distribution gives information about the C2/E2 admixture into the M1 transition from the nucleon to the delta resonance. The quadrupole contributions of this transition has been described in the past by d state admixture due to tensor forces from the gluon and the pion exchange. This yields values which are more then a factor 10 too small compared with recent data for the C2/E2 Sachs transition form factor. We show that meson and gluon pair exchange current can explain the data without the need of a large nucleona without the need of a large nucleon or delta deformation. The same model is than used to describe the nucleon-nucleon phase shift. An essential ingredient for the good agreement is to include to all orders couplings to ? channels. The 1S0 phase shift can only be described in agreement with the data if the coupling to the 5D0 nucleon delta channel is included. (author)

  16. Impact between deformable bodies

    International Nuclear Information System (INIS)

    The bodies are represented by constant strain finite elements so that the element internal forces can most easily be calculated, especially after yielding has taken place when the stress and strain increments are related in accordance with the Prandtl-Reuss theory. In the case of axisymmetrical problems triangular axisymmetrical elements are used whose properties are approximately calculated by sampling at the centroid of the cross-section. The external applied forces arise from the impact and contact forces at the interfaces, and the inertia forces are obtained from lumped mass matrices. The equation of motion is solved by a central difference explicit scheme in small incremental time steps. This enables the stress propagation as well as the history of plastic deformation in the bodies to be traced throughout the duration of impact. The material law is idealised to be piecewise linear, with an initial elastic portion followed by one linear hardening segment. Perfect plasticity (zero hardening) can also be allowed. A simple procedure deals with the case of loading from an elastic initial state to a final plastic state in one time step. The program has been applied to the investigation of a number of axisymmetrical problems. The three dimensional version of the program is now being coded. Examples: impact of a falling fuel stringer in a storage tube; impact of a cylinder on a rigid boundary; supported circular plate loaded by uniformly distributed impulses; impact of aniformly distributed impulses; impact of a non-return valve in a pipe rupture; impact of a cylindrical fuel-waste flask; impact of a conical missile on a rigid surface. (orig./HP)

  17. Superplastic deformation of nitrogen-rich Ca-?-sialon ceramics

    International Nuclear Information System (INIS)

    Nitrogen-rich Ca-?-sialon ceramics, prepared with CaH2 as one of the starting powders, were compressively deformed in spark plasma sintering equipment. Compared with the oxygen-rich Ca-?-sialons, increasing onset deformation temperatures (about 150 K higher) were observed for nitrogen-rich Ca-?-sialons deformed at a rate of 2 x 10-3 s-1. High hardness (HV10 = 18-20 GPa) and toughness (KIC = 4-7 MPa m1/2) were maintained after the deformation. Anisotropic grain growth was found to take place during deformation, resulting in anisotropic microstructures, containing coarse and elongated grains. The observed differences in deformation behaviour and properties between nitrogen-rich and oxygen-rich Ca-?-sialons are, as indicated by transmission electron microscopy and electron energy loss spectroscopy analysis, attributed to the presence of reduced amounts of a nitrogen-rich grain-boundary glass phase

  18. Strains, stresses and elastic properties in polycrystalline metallic thin films: in situ deformation combined with x-ray diffraction and simulation experiments

    International Nuclear Information System (INIS)

    X-ray diffraction is used in combination with tensile testing for measuring elastic properties of metallic thin films. Size effect, elastic anisotropy and grain morphologies are considered in all these experiments and supported by different kind of numerical simulations operating at different length scales. Such instrumental studies are time consuming even if synchrotron sources are used. New experiments are under progress for reducing acquisition data and improving precision on strain measurements. After introducing briefly the main principles and results of our techniques, first promising measurements on nano-metric W/Cu multilayers using 2D CCD detectors and high monochromatic flux at the Advanced Light Source Berkeley (USA) on beam line 11.3.1 are presented. In addition, simulation experiments for analyzing elasticity in textured gold film are discussed. (authors)

  19. Almost Kaehler deformation quantization

    CERN Document Server

    Karabegov, A V; Karabegov, Alexander V.; Schlichenmaier, Martin

    2001-01-01

    We use a natural affine connection with nontrivial torsion on an arbitrary almost-Kaehler manifold which respects the almost-Kaehler structure to construct a Fedosov-type deformation quantization on this manifold.

  20. Rock Deformation Meeting

    Science.gov (United States)

    Green, Harry

    The Third Rock Deformation Colloquium was held December 4, 1989, at the AGU Fall Meeting in San Francisco. Steve Kirby of the U.S. Geological Survey, Menlo Park, Calif., reported on actions taken by the rock deformation steering committee. Brian Wernicke of Harvard University, Cambridge, Mass., talked on the structural geology of the Great Basin.The steering committee voted for “Committee on Deformation of Earth Materials” as the name for the AGU technical committee on rock deformation, Kirby said. Considerable discussion has occurred in the steering committee over our relationship to the AGU Mineral Physics Committee. Indeed, Kirby will become chairman of that committee in 1990, underlining the overlap of the two groups. It was agreed that we will pursue closer association with Mineral Physics.