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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.

2010-01-01

2

Octupole Deformed Nuclei in the Actinide Region  

CERN Multimedia

% IS322 \\\\ \\\\ The aim of the present study is to investigate the limits of the $^{\\prime\\prime}$island$^{\\prime\\prime}$ 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

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

3

Octupole Correlations and Deformation In Ba, La and Pr  

International Nuclear Information System (INIS)

Stable octupole deformation was predicted and subsequently found to occur centered around the reinforcing shell gaps at Z=56 and N=88 for ?3?0.15. Evidence for stable octupole deformation is reviewed. New results in 145Ba and 141Ba are presented. Rotational enhancement of octupole deformation is found at intermittent spins in Ba and La nuclei and the quenching of such deformation at higher spins in 146Ba but not in 144Ba. Symmetric and asymmetric shapes coexist in 145Ba and 145La. Evidence for octupole correlation is found in 147Pr but only h11/2 bands are found in 149,151Pr. The new 141Ba levels have two sets of two intertwined bands of levels with the characteristics of octupole deformation as found in 143,145Ba, however, a problem occurs with the assignment of parities in 141Ba. (author)

2001-01-01

4

Strong and weak coupling to the octupole deformed mode in /sup 227/Ac/sub 89/  

Energy Technology Data Exchange (ETDEWEB)

Hybrid values of the intrinsic gyromagnetic ratio and the absolute values of the decoupling parameters have been found for two sets of approximately degenerate opposite parity bands with K = (3/2)/sup + -/ and K = (1/2)/sup + -/ in /sup 227/Ac, as would be expected for intrinsic parity mixing in the single-particle states due to octupole deformation. These properties are able to test quantitatively the change in the Nilsson wave functions resulting from octupole deformation.

Sheline, R.K.; Leander, G.A.

1983-08-01

5

Experimental tests for stable octupole deformation in actinium-227  

International Nuclear Information System (INIS)

[en] 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

1986-01-01

6

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.

1986-01-01

7

Search for octupole deformation in neutron rich Xe isotopes  

International Nuclear Information System (INIS)

A search for octupole deformation in neutron rich Xe isotopes has been conducted through gamma-ray spectroscopy of primary fragments produced in the spontaneous fission of 248Cm. The spectrometer consisted of the Eurogam array and a set of 5 LEPS detectors. Level schemes were constructed for Xe isotopes with masses ranging from 138 to 144. Except for 139Xe, none of them exhibit an alternating parity quasimolecular band, ? feature usually encountered in octupole deformed nuclei. Substantial evidence for reflection asymmetric shape in the intrinsic system of the nucleus exists for the light actinide nuclei

1994-01-01

8

The Structure of Heavy Octupole and Superheavy Quadrupole Deformed Nuclei  

International Nuclear Information System (INIS)

We report here experimental attempts to determine the sign of the electric dipole moment (relative to the electric octupole moment) in the octupole deformed nucleus 226Ra. Sensitivity to this quantity is observed in the measured yields of ?-ray transitions following very low energy Coulomb excitation. Recent progress is also reported in the development of new spectroscopic techniques that promise to elucidate the structure of deformed superheavy nuclei in the region of 254No. The 4+?2+ transition in 254No as well as higher spin transitions, has been identified using recoil-tagged conversion electron spectroscopy. (author)

2001-01-01

9

Octupole Correlations in the Pu Isotopes: From Vibration to Static Deformation?  

Energy Technology Data Exchange (ETDEWEB)

In a series of measurements with Gammasphere, striking differences were found between the yrast and negative parity bands in {sup 238{endash} 240}Pu and those in {sup 241{endash} 244}Pu . These differences can be linked to variations with mass of the strength of octupole correlations. At the highest spins, {sup 238{endash} 240}Pu are found to exhibit properties associated with stable octupole deformation, suggesting that a transition with spin from a vibration to stable deformation may have occurred. {copyright} {ital 1999} {ital The American Physical Society}

Wiedenhoever, I.; Janssens, R.V.; Ahmad, I.; Greene, J.P.; Amro, H.; Carpenter, M.P.; Cizewski, J.; Khoo, T.L.; Lauritsen, T.; Lister, C.J.; Nisius, D.T.; Reiter, P.; Seweryniak, D.; Siem, S.; Sonzogni, A.; Uusitalo, J. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Hackman, G. [University of Kansas, Lawrence, Kansas 66045 (United States); Amro, H.; Amro, H. [Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708-0308 (United States); Bhattacharyya, P.K. [Purdue University, West Lafayette, Indiana 47907 (United States); Chowdhury, P.; Seabury, E.H. [University of Massachusetts, Lowell, Massachusetts 01854 (United States); Cizewski, J. [Rutgers University, New Brunswick, New Jersey 08903 (United States); Cline, D.; Wu, C.Y. [University of Rochester, Rochester, New York 14627 (United States); Macchiavelli, A.O. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Siem, S. [University of Oslo, Oslo, Norway] [University of Geneva, CH-1211 Geneva 4 (Switzerland)

1999-09-01

10

Dipole and octupole pairs in deformed actinide nuclei  

Science.gov (United States)

The structure of deformed actinide nuclei is studied in terms of an intrinsic hamiltonian containing an octupole mean field in addition to a quadrupole field (Nilsson potential). It is shown that there is a significant amount of the collective dipole (1-) nucleon pair in the wave function of low-lying states, and that the dipole mode, for instance the dipole boson, has to be included in the description of such nuclei as well as the octupole one. The author acknowledges Professor A. Arima, Dr. N. Yoshida, Dr. N. Yoshinaga and Dr. M. Sugita for valuable discussions.

Otsuka, Takaharu

1986-12-01

11

Octupole deformation and signature inversion in 145Ba  

International Nuclear Information System (INIS)

High spin states in neutron-rich odd-N 145Ba nucleus have been investigated from study of prompt ?-rays in spontaneous fission of 252Cf. The alternating parity bands are identified indicating octupole deformation with simplex quantum number s = -i. The ground state band shows signature splitting and inversion at low spin. These collective band structures exhibit the competition and co-existence between symmetric and asymmetric shapes

1999-01-01

12

Aligned rotation of octupole-vibrational states in deformed nuclei  

International Nuclear Information System (INIS)

Analysis of level energies in aligned octupole bands in even-even deformed nuclei using the VMI-model expressed in terms of the rotational angular momentum R, show that almost complete alignment is reached at low spin values. It is shown that the alignment is almost spin independent. Using the ground-state band VMI-parameters only a renormalization of the alignment parameter is enough to reproduce the level energies of the NPB's. (orig.)

1977-01-01

13

New signatures for octupole deformation in some actinide nuclei  

Science.gov (United States)

Energies for three positive and three negative parity bands predicted by the extended coherent state model in 218,226Ra, 228Th, 232Th, in four uranium even-mass isotopes, 232-238U, and in 238Pu, are calculated and used to point out new signatures for octupole deformation in ground as well as in ? and ? bands. A beat pattern is found by using a new displacement energy function, which is more appropriate for a spectrum that exhibits large deviations from a linear J(J+1) dependence.

Raduta, A. A.; Ionescu, D.

2003-04-01

14

Octupole deformation in sup 221 Fr; E1 transition rates  

Energy Technology Data Exchange (ETDEWEB)

Experimental data following the alpha decay of{sup 225}Ac are interpreted in terms of a spectroscopy in {sup 221}Fr consistent with octupole deformation. However, the measured E1 transition probabilities suggest that the low lying bands in {sup 221}Fr are considerably more mixed than in nuclei with slightly higher mass number. It is suggested that this mixing of states in {sup 221}Fr is indicative of the partial collapse of Nilsson-like orbitals into more degenerate shell model orbitals.

Liang, C.F.; Peghaire, A. (Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, Bat. 104-91406 Campus Orsay (FR)); Sheline, R.K. (Florida State Univ., Tallahassee, FL (USA))

1990-07-10

15

Description of octupole-deformed nuclei within the interacting boson and interacting boson-fermion models  

Energy Technology Data Exchange (ETDEWEB)

We carry out an intrinsic frame analysis of octupole-deformed nuclei in the SU(3) limit of the extended interacting boson model. Excited bands associated with nuclei exhibiting permanent octupole deformation are studied, as well as the behaviour of in-band and intra-band transitions, and the results are applied to {sup 226}Ra. The coupling of an odd particle to an even core with these characteristics is also discussed. ((orig.)).

Alonso, C.E. [Departamento di Fisica Atomica, Molecular y Nuclear, Sevilla (Spain); Arias, J.M. [Departamento di Fisica Atomica, Molecular y Nuclear, Sevilla (Spain); Frank, A. [Departamento di Fisica Atomica, Molecular y Nuclear, Sevilla (Spain); Sofia, H.M. [Comision Nacional de Energia Atomica, Buenos Aires (Argentina); Lenzi, S.M. [Dipartimento di Fisica and INFN, Padova (Italy); Vitturi, A. [Dipartimento di Fisica and INFN, Padova (Italy)

1995-04-03

16

About collective states for even-even nuclei with quadrupole and octupole deformations  

CERN Document Server

The simple analytic expressions for the energy of even and odd rotational-vibrational levels in deformable even-even nuclei with quadrupole and octupole deformations have been obtained. The calculated level energy values including levels with high spins are in good agreement with experimental data.

Sharipov, S M; Nuriev, S K

2002-01-01

17

Possible octupole deformation in Cs and Ba nuclei from their differential radii  

Energy Technology Data Exchange (ETDEWEB)

The odd-even staggering of the differential radii of Fr and Ra and the Cs and Ba nuclei is compared. This staggering is inverted in the region of known octupole deformation in the Fr and Ra nuclei. The normal staggering is eliminated in the Cs nuclei and attenuated in the Ba nuclei for neutron numbers 85--88. This fact is used to suggest the possible existence of octupole deformation and its neutron number range in the Cs and Ba nuclear ground states.

Sheline, R.K.; Jain, A.K.; Jain, K.

1988-12-01

18

Exotic octupole deformation in proton-rich Z=N nuclei  

Energy Technology Data Exchange (ETDEWEB)

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)

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

1998-03-01

19

Analysis of neutron scattering by even-even nuclei with allowance for dynamical octupole deformations  

International Nuclear Information System (INIS)

The possibility of taking into account dynamical octupole deformations in the description of vibrational and rotational states of negative parity is considered. This description is based on the model of a quadrupole-deformed nonaxial rotator. The wave functions of the model are used to construct the strong-coupling scheme. The parameters of the Hamiltonian and deformed optical potential are found for 76Se and 238U. A self-consistent description is obtained for spectroscopic data and experimental data on neutron scattering by these nuclei

1996-01-01

20

Non-Axial Octupole Deformations and Tetrahedral Symmetry in Heavy Nuclei  

International Nuclear Information System (INIS)

The total energies of about 120 nuclei in the Thorium region have been calculated within the macroscopic-microscopic method in the 5-dimensional space of deformation parameters ?20, ?22, ?30, ?32 and ?40. The macroscopic energy term contains the nuclear surface-curvature dependence as proposed within the LSD approach. The microscopic energies are calculated with the Woods-Saxon single particle potential employing the universal set of parameters.We study a possible presence of the octupole axial and non-axial degrees of freedom all-over in the (?, ?)-plane focussing on the ground-states, secondary minima and in the saddle points. In fact, a competition between axial and tri-axial octupole deformation parameters is obtained at the saddle points and in the secondary minima for many isotones with N > 136. The presence of the tetrahedral symmetry minima is predicted in numerous nuclei in the discussed region, although most of the time at relatively high excitation energies.

2005-11-21

 
 
 
 
21

Octupole deformation and Ra puzzle in reflection asymmetric covariant density functional theory  

CERN Multimedia

Reflection asymmetric covariant density functional theory(CDFT) based on the point-coupling interaction is established on a two-center harmonic-oscillator basis and applied to investigate the Ra puzzle, i.e., the anomalous enhancement of the residual proton-neutron interactions for Ra isotopes around N=135. The octupole deformation and shape evolution in the Ra and Rn isotopes are examined in the potential energy surfaces in(beta2, beta3) plane by the constrained reflection asymmetric calculations. The residual proton-neutron interactions extracted from the double difference of the binding energies for Ra isotopes are compared with the data as well as the axial and the triaxial calculations. It is found that the octupole deformation is responsible for the Ra puzzle in the microscopic CDFT.

Yu, L F; Zhang, S Q; Meng, J

2012-01-01

22

Collective {ital T}- and {ital P}-odd electromagnetic moments in nuclei with octupole deformations  

Energy Technology Data Exchange (ETDEWEB)

Parity and time invariance violating forces produce collective {ital P}- and {ital T}-odd moments in nuclei with static octupole deformation. Collective Schiff moment, electric octupole and dipole, and also magnetic quadrupole appear due to the mixing of rotational levels of opposite parity and can exceed single-particle moments by more than a factor of 100. This enhancement is due to two factors, the collective nature of the intrinsic moments and the small energy separation between members of parity doublets. The above moments induce {ital T}- and {ital P}-odd effects in atoms and molecules. Experiments with such systems may improve substantially the limits on time reversal violation. {copyright} {ital 1996 The American Physical Society.}

Auerbach, N.; Flambaum, V.V.; Spevak, V. [School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel)]|[School of Physics, University of New South Wales, Sydney, 2052, New South Wales (Australia)

1996-06-01

23

Anomalous E1 conversion in octupole-deformed nuclei and muon shake-off in prompt fission  

Energy Technology Data Exchange (ETDEWEB)

It has been shown that the coexistence of octupole and quadrupole deformation in nuclei gives rise to strong penetration effects in internal conversion for the E1 transitions. This idea has been applied for evaluating the muon shake-off probability W{sub sh}. The value obtained, W{sub sh}{approx equal}0.5% per prompt fission, is in good agreement with the experimental result. Possibilities for further experimental studies of this effect are discussed. (orig.).

Karpeshin, F.F. (St. Petersburg State Univ. (Russia) Bonn Univ. (Germany). Inst. fuer Strahlen- und Kernphysik)

1992-11-01

24

Quadrupole and octupole shapes in nuclei  

Energy Technology Data Exchange (ETDEWEB)

The heavy-ion multiple Coulomb excitation technique, which has benefited from many important contributions by Dick Diamond, has developed to the stage where rather complete sets of E1, E2 and E3 matrix elements are being measured. These provide a sensitive measures of quadrupole and octupole deformation in nuclei. The completeness of the E2 data is sufficient to determine directly the centroids and fluctuation widths of the E2 properties in the principal axis frame for low-lying states. The results and model implications of recent Coulomb excitation measurements of the quadrupole shapes in odd and even A nuclei will be presented. Recent measurements of E1, E2 and E3 matrix elements for collective bands in N=88 and Z=88 nuclei show that octupole correlations play an important role. These results and the implications regarding octupole deformation and reflection asymmetry will be discussed.

Cline, D. [Univ. of Rochester, NY (United States)

1993-12-31

25

Octupole shapes in heavy nuclei  

Energy Technology Data Exchange (ETDEWEB)

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.

Ahmad, I.

1994-08-01

26

Octupole shapes in heavy nuclei  

International Nuclear Information System (INIS)

[en] 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

1994-01-01

27

Identification of Excited States in {sup 226}U: Evidence for Octupole Deformation  

Energy Technology Data Exchange (ETDEWEB)

The level scheme of {sup 226}U has been deduced from the results of two experiments carried out at the University of Jyvaskyla, Finland. Both {alpha}- and {gamma}-ray-spectroscopic techniques have been employed. The interleaved states of positive- and negative-parity indicate the octupole nature of this nucleus, and the behavior of the difference in aligned angular momentum between the positive- and negative-parity bands as a function of rotational frequency is consistent with that expected for a rotating reflection-asymmetric shape.

Greenlees, P.T.; Amzal, N.; Andreyev, A.; Butler, P.A.; Cann, K.J.; Cocks, J.F.C.; Dorvaux, O.; Enqvist, T.; Fallon, P.; Gall, B.; Guttormsen, M.; Hawcroft, D.; Helariutta, K.; Hessberger, F.P.; Hoellinger, F.; Jones, G.D.; Jones, P.; Julin, R.; Juutinen, S.; Kankaanpaa, H.; Kettunen, H.; Kuusiniemi, P.; Leino, M.; Messelt, S.; Muikku, M.; Odegard, S.; Page, R.D.; Savelius, A.; Schiller, A.; Siem, S.; Trzaska, W.H.; Tveter, T.; Uusitalo, J.

1999-12-31

28

Identification of Excited States in 226U: Evidence for Octupole Deformation  

International Nuclear Information System (INIS)

The level scheme of 226U has been deduced from the results of two experiments carried out at the University of Jyvaskyla, Finland. Both ?- and ?-ray-spectroscopic techniques have been employed. The interleaved states of positive- and negative-parity indicate the octupole nature of this nucleus, and the behavior of the difference in aligned angular momentum between the positive- and negative-parity bands as a function of rotational frequency is consistent with that expected for a rotating reflection-asymmetric shape.

1999-01-01

29

Octupole effects in the lanthanides  

International Nuclear Information System (INIS)

Arrays of Anti-Compton Spectrometer enabled systematic investigations of octupole correlations in the neutron-rich lanthanides. The studies mostly confirm the theoretical expectations of moderate octupole deformation at medium spins in nuclei from this region but in some cases predictions deviate from the experiment. In cesium isotopes strong octupole effects are predicted but not observed and new measurements for 139Xe suggest octupole effects stronger than expected. Systematics of excitation energy of the 31 states excitations, updated in the present work for Xe isotopes, indicates the N=85 and Z=54 lines as borders for strong octupole correlations. Systematic of electric dipole moment, upgraded in the present work for Ca and Ce isotopes confirms the Z=54 limit and adds new information about local canceling of electric dipole moment at the N=90 neutron number.

1999-07-02

30

Unexpected 5/2- spin of the ground state in 147Ba: No octupole deformation in ground states of odd-A Ba isotopes  

Science.gov (United States)

The 147Ba nucleus has been studied in prompt ?-ray spectroscopy using the EUROGAM2 Ge array. Spin and parity of the ground state has been determined to be 5/2-. The unexpected, 5/2- ground state results from interaction with other negative-parity configurations. A new ground-state band has been established in 147Ba and some previously reported levels have been arranged into a 3/2- band, which may correspond to the 3/2-[532] configuration. The new spin assignments in 147Ba suggest that the theoretical predictions of static octupole deformation in the ground state of 147Ba may not be be valid. No candidates for parity doublets have been found in 147Ba. Instead, an octupole band built on the ground state has been proposed.

Rz?ca-Urban, T.; Urban, W.; Smith, A. G.; Ahmad, I.; Syntfeld-Ka?uch, A.

2013-03-01

31

Octupole Strength in the ^238,240,242Pu isotopes  

Science.gov (United States)

A series of so-called ``unsafe'' Coulomb excitation experiments as well as 1-neutron transfer measurements was carried out with Gammasphere at the ATLAS accelerator in order to investigate the collective properties of ^238,240,242Pu. New experimental evidence has emerged that in ^240Pu a transition from an octupole vibration to stable octupole deformation occurs at high spin. A similar situation may be present in ^238Pu, but is clearly absent in the heavier ^ 242Pu. The data will be presented and discussed together with available information on neighboring nuclei in the region.

Wang, X.; Zhu, S.; Janssens, R. V. F.; Carpenter, M. P.; Ahmad, I.; Greene, J. P.; Khoo, T. L.; Kondev, F. G.; Lauritsen, T.; Lister, C. J.; Seweryniak, D.; Freeman, S. J.; Garg, U.; Wiedenh{"O}Ever, I.; Bernstein, A.; Wilson, P.; Diffenderfer, E.; Teal, C.; Larabee, A.; Meredith, B.

2006-10-01

32

Octupole correlations in the heavy elements  

Energy Technology Data Exchange (ETDEWEB)

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 2/sup 6/-pole deformation and fast El transitions to an octupole model is considered. 30 refs., 21 figs., 1 tab.

Chasman, R.R.

1986-01-01

33

Quadrupole and octupole shapes in nuclei  

Energy Technology Data Exchange (ETDEWEB)

This paper outlines the Coulomb excitation technique and presents examples addressing quadrupole deformation in the strongly-deformed nuclei, double-[gamma] bands in even-A osmium nuclei, and the implications of recent measurements of E3 and E1 matrix elements regarding the role of octupole deformation in nuclear structure. (orig.)

Cline, D. (Nuclear Structure Research Lab., Univ. of Rochester, NY (United States))

1993-05-31

34

Octupole vibrations in nuclei  

Energy Technology Data Exchange (ETDEWEB)

Phenomenological - geometric and algebraic - and microscopic approaches to the problem of octupole vibrations in nuclei are reviewed. In particular, the collective model of nuclear octupole motion, its structure and symmetries are recapitulated in detail. Theoretical descriptions are compared with experimental data. We also try to elucidate a peculiarity of the octupole degrees of freedom.

Rohozinski, S.G.

1988-04-01

35

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

1993-01-01

36

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

Energy Technology Data Exchange (ETDEWEB)

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.

Xiu, L.; Ohnuma, Shoroku; Wang, K. [Houston Univ., TX (United States). Dept. of Physics; Meitzler, C.R.; Xu, Y. [Sam Houston State Univ., Huntsville, TX (United States). Dept. of Physics

1993-06-01

37

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

Energy Technology Data Exchange (ETDEWEB)

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.

Xiu, L.; Ohnuma, Shoroku; Wang, K. (Houston Univ., TX (United States). Dept. of Physics); Meitzler, C.R.; Xu, Y. (Sam Houston State Univ., Huntsville, TX (United States). Dept. of Physics)

1993-01-01

38

Octupole collectivity in the Sm isotopes  

International Nuclear Information System (INIS)

Microscopic models suggest the occurrence of strong octupole correlations in nuclei with N?88. To examine the signatures of octupole correlations in this region, the spdf Interacting Boson Approximation (IBA) Model is applied to the Sm isotopes with N = 86 - 92. The effects of including multiple negative parity bosons in the basis are compared to more standard one negative parity boson calculations and are analyzed in terms of signatures for strong octupole correlations. It is found that multiple negative parity bosons are needed to describe properties at medium spin. Bands with strong octupole correlations (multiple negative parity bosons) become yrast at medium spin in 148,150Sm. This region shares some similarities with the light actinides, where strong octupole correlations were also found at medium spin. (orig.)

2005-01-01

39

Octupole collectivity in the Sm isotopes  

International Nuclear Information System (INIS)

Microscopic models suggest the occurrence of strong octupole correlations in nuclei with N?88. To examine the signatures of octupole correlations in this region, the spdf interacting boson approximation model is applied to Sm isotopes with N=86-92. The effects of including multiple negative-parity bosons in this basis are compared with more standard one negative-parity boson calculations and are analyzed in terms of signatures for strong octupole correlations. It is found that multiple negative-parity bosons are needed to describe properties at medium spin. Bands with strong octupole correlations (multiple negative-parity bosons) become yrast at medium spin in 148,150Sm. This region shares some similarities with the light actinides, where strong octupole correlations were also found at medium spin

2005-01-01

40

Octupole vibrations at high angular momenta  

International Nuclear Information System (INIS)

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 vibration. 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. (author). 20 refs, 6 figs, 1 tab

1995-09-02

 
 
 
 
41

Simultaneous quadrupole and octupole shape phase transitions in Thorium  

CERN Multimedia

The evolution of quadrupole and octupole shapes in Th isotopes is studied in a fully microscopic framework based on nuclear Density Functional Theory. The constrained potential 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 nucleon number. $^{224}$Th is predicted closest to the critical point of the double phase transition. A microscopic mechanism of this phenomenon is discussed in terms of the evolution of single-nucleon orbitals with deformation.

Li, Z P; Yao, J M; Vretenar, D; Meng, J

2013-01-01

42

Extension of the multiphonon method to odd mass deformed nuclei. Part. 2. Application to the spectroscopic study of light actinium  

Energy Technology Data Exchange (ETDEWEB)

The multiphonon method based on the collective K=0/sup -/ octupole state is applied to the study of the low energy spectroscopic properties of /sup 223 -225 -227/Ac. Special attention is paid to various arguments usually invoked to assert that these isotopes have stable octupole deformation. A new criterium is proposed. (orig.).

Piepenbring, R.

1986-03-01

43

Electron scattering from the octupole band in 238U  

International Nuclear Information System (INIS)

[en] A simple model for nuclear surface vibrations in permanently deformed nuclei does well in reproducing electron scattering cross sections of rotational levels built on a K/sup ?/= 0- intrinsic octupole vibration in 238U

1978-03-06

44

Evidence for octupole vibration in the superdeformed well of {sup 109}Hg  

Energy Technology Data Exchange (ETDEWEB)

An excited superdeformed (SD) band has been observed in {sup 19O}Hg which decays to the lowest-energy (yrast) SD band rather than to the less deformed states as observed in most known SD bands in the A{approximately}150 and A{approximately}190 regions. The band exhibits properties which are in good agreement with predictions of collective octupole vibrations in the SD well of {sup 19O}Hg.

Crowell, B.; Janssens, R.V.F.; Carpenter, M.P.; Ahmad, I.; Harfenist, S.; Henry, R.G.; Khoo, T.L.; Lauritsen, T.; Nisius, D. [Argonne National Lab., IL (United States); Wilson, A.N. [Univ. of Liverpool (United Kingdom)] [and others

1994-07-01

45

Configuration Mixing and Octupole Studies of Nuclei Within the Interacting Boson Model.  

Science.gov (United States)

The Interacting Boson Model (IBM) has been very successful in describing the collective properties of nuclei. This work concerns two systematic applications of the model, one involving configuration mixing, and the other involving octupole bands. The even isotopes of mercury are of special interest because of the coexistence of two sets of bands, of very different character, in the lighter nuclei. The neutron -proton IBM (IBM-2) with configuration mixing provides a good description, both of states built on the normal ground state and of those associated with a proton pair excitation across the Z = 82 closed-shell gap. Eleven isotopes are studied, ranging from the middle of the neutron shell to very near the doubly closed shell at ('208)Pb. The same Hamiltonian is used for all the nuclei studied, with parameters which are constant or smoothly varying. There have been extensive IBM studies of low-lying positive parity bands, which are based on the ground state and the quadrupole degree of freedom. The present work comprises the first systematic IBM study of the corresponding negative parity bands, which are based on the octupole degree of freedom. In this model, an f boson is coupled to a positive parity core, described by the usual s and d bosons. This is done within the original IBM framework, called IBM-1, which does not include separate neutron and proton degrees of freedom. The IBM octupole model is presented and the phenomenology is explored, both for the full model, and for the SU(3) limit of the model. Calculated energy spectra and B(E3) transition rates are presented for nine deformed rare-earth nuclei. There is good agreement with available experimental data for these nuclei. It is shown that nuclei for which the two lowest octupole bands are K = 2 and 0 cannot be described within the present model. In this case, it appears that separate neutron and proton octupole degrees of freedom are necessary. The exchange term in the Hamiltonian is shown to arise from a neutron-proton octupole-octupole interaction. A consistent octupole model is developed and successfully applied to the nucleus ('168)Er.

Barfield, Ariel Foote

46

Octupole instability in the heavy barium region  

Energy Technology Data Exchange (ETDEWEB)

Quasi-molecular rotational bands characterized by spin states of alternating parity connected by enhanced E1 transitions have recently been observed in several transitional nuclei around /sup 224/Th. The appearance of such bands can easily be understood by assuming the absence of intrinsic parity symmetry in these nuclei. Another likely region on the chart of nuclides to find octupole-unstable nuclei is the region of nuclei around /sup 146/Ba. In fact, in several Xe, Ba and Ce isotopes with n approximately equal to 88, calculations yield octupole-unstable ground states. The main goal of the present study was to calculate equilibrium deformations of doubly-even Xe, Ba, Ce, Nd, Sm and Gd nuclei with neutron numbers between 84 and 94. The method used was the Woods-Saxon-Bogolyubov cranking model method combined with the shell correction approach. The results of these calculations confirm previous expectations of octupole deformed mean fields at low and medium spins in Xe-Sm nuclei with neutron numbers around N = 86. Recent experimental data support theoretical results. 8 refs., 1 fig. (DWL)

Nazarewicz, W.; Leander, G.A.; Tabor, S.

1987-01-01

47

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

1993-01-01

48

Chromaticity dependence on octupole strength  

CERN Multimedia

The first measurements of the dependence of the chromaticity on the lattice octupole strength were performed at the LHC in a machine development session on Wednesday 20 June 2012. This chromaticity change is non negligible and needs to be taken into account when changing the octupole strength, e.g. for beam stabilization purposes. We report on the results of such measurements and later ones, along with some predictions and some first estimates of systematic horizontal and vertical misalignments of the octupoles.

Herr, W; Metral, E; Mounet, N; Papotti, G; Tomas Garcia, R; Wenninger, J

2012-01-01

49

Octupole response and stability of spherical shape in heavy nuclei  

Energy Technology Data Exchange (ETDEWEB)

The isoscalar octupole response of a heavy spherical nucleus is analyzed in a semiclassical model based on the linearized Vlasov equation. The octupole strength function is evaluated with different degrees of approximation. The zero-order fixed-surface response displays a remarkable concentration of strength in the 1{Dirac_h}{omega} and 3{Dirac_h}{omega} regions, in excellent agreement with the quantum single-particle response. The collective fixed-surface response reproduces both the high- and low-energy octupole resonances, but not the low-lying 3{sup -} collective states, while the moving-surface response function gives a good qualitative description of all the main features of the octupole response in heavy nuclei. The role of triangular nucleon orbits, that have been related to a possible instability of the spherical shape with respect to octupole-type deformations, is discussed within this model. It is found that, rather than creating instability, the triangular trajectories are the only classical orbits contributing to the damping of low-energy octupole excitations.

Abrosimov, V.I.; Davidovskaya, O.I.; Dellafiore, A. E-mail: della@fi.infn.it; Matera, F

2003-11-17

50

Octupole response and stability of spherical shape in heavy nuclei  

International Nuclear Information System (INIS)

The isoscalar octupole response of a heavy spherical nucleus is analyzed in a semiclassical model based on the linearized Vlasov equation. The octupole strength function is evaluated with different degrees of approximation. The zero-order fixed-surface response displays a remarkable concentration of strength in the 1?? and 3?? regions, in excellent agreement with the quantum single-particle response. The collective fixed-surface response reproduces both the high- and low-energy octupole resonances, but not the low-lying 3- collective states, while the moving-surface response function gives a good qualitative description of all the main features of the octupole response in heavy nuclei. The role of triangular nucleon orbits, that have been related to a possible instability of the spherical shape with respect to octupole-type deformations, is discussed within this model. It is found that, rather than creating instability, the triangular trajectories are the only classical orbits contributing to the damping of low-energy octupole excitations.

2003-11-17

51

Global systematics of octupole excitations in even-even nuclei  

Science.gov (United States)

We present a computational methodology for a theory of the lowest axially symmetric octupole excitations applicable to all even-even nuclei beyond the lightest. The theory is the well-known generator-coordinate extension (GCM) of the Hartree-Fock-Bogoliubov (HFB) self-consistent mean field theory. We use the discrete-basis Hill-Wheeler (HW) method to compute the wave functions with an interaction from the Gogny family of Hamiltonians. Comparing to the compiled experimental data on octupole excitations, we find that the performance of the theory depends on the deformation characteristics of the nucleus. For nondeformed nuclei, the theory reproduces the energies to about ±20% apart from an overall scale factor of ?1.6. The performance is somewhat poorer for (quadrupole) deformed nuclei, and for both together the dispersion of the scaled energies about the experimental values is about ±25%. This compares favorably with the performance of similar theories of the quadrupole excitations. Nuclei having static octupole deformations in HFB theory form a special category. These nuclei have the smallest measured octupole excitation energies as well as the smallest predicted energies. However, in these cases the energies are seriously underpredicted by the theory. We find that a simple two-configuration approximation, the minimization after projection (MAP) method, is almost as accurate as the full HW treatment, provided that the octupole-deformed nuclei are omitted from the comparison. This article is accompanied by a tabulation of the predicted octupole excitations for 818 nuclei extending from drip-line to drip-line, computed with several variants of the Gogny interaction.

Robledo, L. M.; Bertsch, G. F.

2011-11-01

52

Octupole response and stability of spherical shape in heavy nuclei  

CERN Document Server

The isoscalar octupole response of a heavy spherical nucleus is analyzed in a semiclassical model based on the linearized Vlasov equation. The octupole strength function is evaluated with different degrees of approximation. The zero-order fixed-surface response displays a remarkable concentration of strength in the $1\\hbar\\omega$ and $3\\hbar\\omega$ regions, in excellent agreement with the quantum single-particle response. The collective fixed-surface response reproduces both the high- and low-energy octupole rsonances, but not the low-lying $3^{-}$ collective states, while the moving-surface response function gives a good qualitative description of all the main features of the octupole response in heavy nuclei. The role of triangular nucleon orbits, that have been related to a possible instability of the spherical shape with respect to octupole-type deformations, is discussed within this model. It is found that, rather than creating instability, the triangular trajectories are the only classical orbits contri...

Abrosimov, V I; Dellafiore, A; Matera, F

2003-01-01

53

Uniform beam distributions using octupoles  

Energy Technology Data Exchange (ETDEWEB)

The Gaussian beam profile of the BNL 200 MeV H{sup {minus}} Linac beam at the Radiation Effects Facility target location was transformed into a rectangular profile with almost uniform distribution by placing two octupole magnetic elements at particular locations along the beam line. Experimental results of the beam profile projection in the horizontal and vertical planes, with and without octupoles, are presented and compared with third order calculations. 7 refs., 3 figs.

Tsoupas, N.; Lankshear, R.; Snead, C.L. Jr.; Ward, T.E.; Zucker, M. (Brookhaven National Lab., Upton, NY (USA)); Enge, H.A. (Deuteron, Inc., Lincoln, MA (USA))

1991-01-01

54

Octupole state properties in /sup 168/Er and the two-neutron /(521 (1/2))(633 (7/2))/ configurational pair  

Energy Technology Data Exchange (ETDEWEB)

Detailed spectroscopy measurements have been made of the gamma rays that follow the deexcitation of /sup 168/Er levels populated in the electron capture decay of /sup 168/Tm. These results, when combined with a reanalysis of Coulomb excitation and inelastic scattering data, provide level lifetime information and support octupole-state Coriolis-coupling calculations. The /(521 (1/2))(633 (7/2))/ two-neutron configurational pair deexcitation rates are compared and some evidence for K mixing among the octupole bands is presented.

Meyer, R.A.; Nethaway, D.R.; Prindle, A.L.; Yaffe, R.P.

1987-04-01

55

Study of octupoles as correctors  

Energy Technology Data Exchange (ETDEWEB)

In an electron microscope equipped with sextupole correctors the ultimate resolution is limited by the fifth-order spherical aberration of the optical system used to form the electron probe. We have examined the possibilities of using octupoles in order to correct this fifth-order spherical aberration. We find that for an electrostatic octupole, the fifth-order aberration is symmetric, while for a magnetic octupole the fifth-order aberration is asymmetric but it is possible to reduce this asymmetry by properly arranging the initial conditions. Based on these results, we propose a system which could be used to correct fifth-order aberration in a probe forming system equipped with a sextupole corrector.

Shao, Z.; Beck, V.; Crewe, A.V.

1988-08-15

56

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

Energy Technology Data Exchange (ETDEWEB)

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 {sup 140}Ba and {sup 152,154}Nd. The largest stable octupole deformation ({beta}{sub s} {approximately} 0.1) is found in {sup 144}Ba{sub as}. The theoretically predicted quenching ({beta}{sub s} {approximately} 0) of stable octupole deformation at higher spins is found in {sup 140}Ba. There is good agreement between theory and experiment for the strongly varying electric dipole moments as a function of mass for {sup 142-141}Ba. In odd-A {sup 142}Ba and odd-Z {sup 140}La, we observe parity doublets, two pairs of positive and negative parity bands with opposite spins. In {sup 145}La a strong coupled ground band with symmetric shape coexists with the asymmetric octupole shape which stabilizes above about spin 19/2. In {sup 145,147}La a strong reduction in E2 strength around 25/2 from band crossing is observed. The isotope {sup 109}Mo was identified and a new region of stable uctpole deformation is identified in {sup 107,108}Mo centered around N = 64-66 as earlier predicted. This is the first case of stable uctpole deformation involving only one pair of orbitals.

Gore, P.M.; Hamilton, J.H.; Hwang, J.K.; Jones, E.F.; Peker, L.K.; Ramayya, A.V.; Zhang, X.Q.; Zhu, S.J.

1998-05-18

57

Octupole and hexadecapole bands in 152Sm  

International Nuclear Information System (INIS)

The nucleus 152Sm is characterized by a variety of low-energy collective modes, conventionally described as rotations, ? vibrations and ? vibrations. Recently, it has been suggested that 152Sm is at a critical point between spherical and deformed collective phases. Consequently, 152Sm is being studied by a variety of techniques, including radioactive decay, multi-step Coulomb excitation, in-beam (?, 2n?) ?-ray spectroscopy and (n, n'?) spectroscopy. The present work focuses on the latter two reactions; these have been used to investigate the low-lying bands associated with the octupole degree of freedom, including one built on the first excited 0+ band. In addition, the K? = 4+ hexadecapole vibrational band has been identified.

2005-10-01

58

Structure and properties of copper deformed by severe plastic deformation methods  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The main object of this study is to establish the influence of severe plastic deformation on the microstructure evolution and properties of polycrystalline copper Cu99.99.Design/methodology/approach: Polycrystalline copper Cu99.99 was deformed by cyclic extrusion compression (CEC), equal channel angular pressing (ECAP) and hydrostatic extrusion (HE). Additionally the combination of these methods were applying to the sample deformations. The microstructure and properties of samples after different kinds of severe mode of deformations (SPD) were examined and compared as well as their properties. The microstructure was investigated by optical (MO) and transmission electron microscopy (TEM). The microhardness was measured by PMT3 microhardness tester.Findings: It was found that increase of deformation diminishing the microstructure and leads to the increase of microhardness of samples.Practical implications: The results may be utilized for determination of a relation between microstructure and properties of the copper deformed in the severe plastic deformation process.Originality/value: The results contribute to evaluation properties of the polycrystalline copper deformed to very large strains exerting the typical range of deformations.

M. Richert; J. Richert; A. Hotlo?; W. Pachla; J. Skiba

2011-01-01

59

Configuration mixing and octupole studies of nuclei within the Interacting Boson Model  

Energy Technology Data Exchange (ETDEWEB)

The Interacting Boson Model (IBM) has been very successful in describing the collective properties of nuclei. This work concerns two systematic applications of the model, one involving configuration mixing, and the other involving octupole bands. The even isotopes of mercury are of special interest because of the coexistence of two sets of bands, of very different character, in the lighter nuclei. The neutron-proton IBM (IBM-2) with configuration mixing provides a good description, both of states built on the normal ground state and of those associated with a proton pair excitation across the Z = 82 closed-shell gap. Eleven isotopes are studied, ranging from the middle of the neutron shell to very near the doubly closed shell at /sup 208/Pb. The same Hamiltonian is used for all the nuclei studied, with parameters which are constant or smoothly varying. The IBM octupole model is presented and the phenomenology is explored, both for the full model, and for the SU(3) limit of the model. Calculated energy spectra and B(E3) transition rates are presented for nine deformed rare-earth nuclei. There is good agreement with available experimental data for these nuclei.

Barfield, A.F.

1986-01-01

60

AGS correction quadrupoles and octupoles  

International Nuclear Information System (INIS)

[en] 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.)

1975-01-01

 
 
 
 
61

Nuclear octupole correlations and the enhancement of atomic time-reversal violation  

Energy Technology Data Exchange (ETDEWEB)

We examine the time-reversal-violating nuclear ''Schiff moment'' that induces electric dipole moments in atoms. After presenting a self-contained derivation of the form of the Schiff operator, we show that the distribution of Schiff strength, an important ingredient in the ground-state Schiff moment, is very different from the electric-dipole-strength distribution, with the Schiff moment receiving no strength from the giant dipole resonance in the Goldhaber-Teller model. We then present shell-model calculations in light nuclei that confirm the negligible role of the dipole resonance and show the Schiff strength to be strongly correlated with low-lying octupole strength. Next, we turn to heavy nuclei, examining recent arguments for the strong enhancement of Schiff moments in octupole-deformed nuclei over that of {sup 199}Hg, for example. We concur that there is a significant enhancement while pointing to effects neglected in previous work (both in the octupole-deformed nuclides and {sup 199}Hg) that may reduce it somewhat, and emphasizing the need for microscopic calculations to resolve the issue. Finally, we show that static octupole deformation is not essential for the development of collective Schiff moments; nuclei with strong octupole vibrations have them as well, and some could be exploited by experiment. (c) 2000 The American Physical Society.

Engel, J. [Department of Physics and Astronomy, CB3255, University of North Carolina, Chapel Hill, North Carolina 27599 (United States); Friar, J. L. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Hayes, A. C. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2000-03-01

62

Search for enhanced octupole correlations in 65Ge  

International Nuclear Information System (INIS)

High spin states of 65Ge have been investigated via the 40Ca(28Si,2pn)65Ge reaction at 93 MeV beam energy. A level scheme containing 36 new transitions and 20 new levels could be established on the basis of ?? and ??n coincidences, ?-angular distributions and ?-linear polarization measurements. The aim of the work was to study the softness with respect to octupole deformation as theoretically predicted for the lightest Ge and Se isotopes. We could definitely show that the excitation energy of the 15/2- state (i.e., the coupling of the g9/2 neutron to the 3- octupole state in 64Ge) is not strongly lowered in comparison to the neighboring Ge nuclei, but fits reasonably well into the trend of smoothly rising energy with decreasing neutron number. Consequently, it should be concluded that the lightest Ge isotopes do not display enhanced octupole correlations, at least in the energy range of Ex?5 MeV.

1995-01-01

63

Search for enhanced octupole correlations in {sup 65}Ge  

Energy Technology Data Exchange (ETDEWEB)

High spin states of {sup 65}Ge have been investigated via the {sup 40}Ca({sup 28}Si,2{ital pn}){sup 65}Ge reaction at 93 MeV beam energy. A level scheme containing 36 new transitions and 20 new levels could be established on the basis of {gamma}{gamma} and {gamma}{gamma}{ital n} coincidences, {gamma}-angular distributions and {gamma}-linear polarization measurements. The aim of the work was to study the softness with respect to octupole deformation as theoretically predicted for the lightest Ge and Se isotopes. We could definitely show that the excitation energy of the 15/2{sup {minus}} state (i.e., the coupling of the {ital g}{sub 9/2} neutron to the 3{sup {minus}} octupole state in {sup 64}Ge) is not strongly lowered in comparison to the neighboring Ge nuclei, but fits reasonably well into the trend of smoothly rising energy with decreasing neutron number. Consequently, it should be concluded that the lightest Ge isotopes do not display enhanced octupole correlations, at least in the energy range of {ital E}{sub {ital x}}{le}5 MeV.

Hermkens, U.; Becker, F.; Burkardt, T.; Eberth, J.; Freund, S.; Mylaeus, T.; Skoda, S.; Teichert, W.; Thomas, H.G.; Werth, A.v.d. [Institut fuer Kernphysik der Universitaet zu Koeln, D-50937 Koeln (Germany)

1995-10-01

64

Octupole degree of freedom for nuclei near 152Sm in a reflection-asymmetric relativistic mean-field approach  

International Nuclear Information System (INIS)

The potential energy surfaces of even-even isotopes near 152Sm are investigated within the constrained reflection-asymmetric relativistic mean-field approach using parameter sets PK1 and NL3. It is shown that the critical-point candidate nucleus 152Sm marks the shape/phase transition not only from U(5) to SU(3) symmetry, but also from the octupole deformed ground state in 150Sm to the quadrupole deformed ground state in 154Sm. The important role of the octupole deformation driving pair (?2f7/2, ?1i13/2) is demonstrated based on the components of the single-particle levels near the Fermi surface. In addition, the patterns of both the proton and the neutron octupole deformation driving pairs (?2f7/2, ?1i13/2) and (?2d5/2, ?1h11/2) are investigated.

2011-09-23

65

Mechanical Properties and Deformation Behavior of Bulk Metallic Glasses  

Directory of Open Access Journals (Sweden)

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.

Dmitri V. Louzguine-Luzgin; Larissa V. Louzguina-Luzgina; Alexander Yu. Churyumov

2012-01-01

66

Modified octupoles for damping coherent instabilities  

International Nuclear Information System (INIS)

[en] The introduction tune spread in circular e+e- accelerators with modified octupoles to reduce the loss of dynamic aperture is discussed. The new magnet design features an octupole of field component on-axis and a tapered field structure off-axis to minimize loss of dynamic aperture. Tracking studies show that the modified octupoles can produce the desired tune spread in SPEAR without compromising confinement of the beam. The technique for designing such magnets is presented, together with an example of magnets that give the required field distribution. 7 refs., 7 figs

1991-01-01

67

Some properties of deformed q-numbers  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english 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 product 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.

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

2009-08-01

68

Geometrical modeling of structure and deformation properties of hybrid composites  

Energy Technology Data Exchange (ETDEWEB)

A geometrical variant of hybrid composite model and explanation for description of deformation properties are proposed. The main elements of such model are composite rods. The structurogram series of composite elements model and composite as a whole were studied. the numerical and quantitative analysis by means of the Videolab-system give us an opportunity to obtain the morphological characteristics of tense regions distribution and general integral structure description. Structure model geometry of hybrid composite with optimum distribution of tense area was determined under stress and shear. The difference between the experimental data and the results of calculation of the classic deformation properties of composite model is about 5--8%.

Yanovsky, Yu.G.; Novikov, V.U.; Tkalenko, R.A. [Institute of Applied Mechanics, Moscow (Russian Federation)]|[Moscow State Open Univ. (Russian Federation)

1993-12-31

69

Octupole correlations in $^{229}Ra$  

CERN Multimedia

The structure of /sup 229/Ra has been studied in the beta /sup -/ decay of /sup 229/Fr. Spins and parities have been determined from the conversion electron measurements, while half-lives for the 137.5, 142.7, 168.8, 213.0 and 479.0 keV levels have been measured in the ps and ns ranges via the fast timing beta gamma gamma (t) method. Our data confirm the previous results and enrich the knowledge of the structure of this nucleus by 25 new states and several strong transitions. Structural similarities are established between /sup 229 /Ra and its N=141 isotone /sup 231/Th. The experimental results are compared with the theoretical predictions of the quasiparticle-phonon model with inclusion of Coriolis coupling. The reduced transition probabilities, and especially the moderately fast B(E1) rate for the 137.5 keV transition connecting the band-heads of the K/sup pi /=5/2 /sup +or-/ parity doublet bands, reveal the presence of significant octupole correlations in /sup 229/Ra. (44 refs).

Fraile-Prieto, L M; García-Borge, M J; Fogelberg, B; García-Raffi, L M; Grant, I S; Gulda, K; Hagebø, E; Kurcewicz, W; Kvasil, J; Løvhøiden, G; Mach, H; Mackova, A; Martínez, T; Rubio, B; Taín, J L; Teijeiro, A G; Tengblad, O; Thorsteinsen, T F

1999-01-01

70

In-situ studies of bulk deformation structures: Static properties under load and dynamics during deformation  

DEFF Research Database (Denmark)

The main goal of the study presented in this thesis was to perform in-situ investigations on deformation structures in plastically deformed polycrystalline copper at low degrees of tensile deformation (<5%). Copper is taken as a model system for cell forming pure fcc metals. Anovel synchrotron-radiation based technique High Angular Resolution 3DXRD has been developed at the 1-ID beam-line at the Advanced Photon Source. The technique extents the 3DXRD approach, to 3D reciprocal space mapping with a resolution of ? 1 · 10?3Å?1 and allows for in-situmapping of reflections from deeply-embedded individual grains in polycrystalline samples during tensile deformation. We have shown that the resulting 3D reciprocal space maps from tensile deformed copper comprise a pronounced structure, consisting of bright sharp peaks superimposed on a cloud of enhanced intensity. Based on the integrated intensity, the width of the peaks, and spatial scanning experiments it is concluded that the individual peaks arise from individual dislocation-free regions (the subgrains) in the dislocation structure. The cloud is attributed to the dislocation rich walls. Samples deformed to 2% tensile strain were investigated under load, focusing on grains that have the tensile direction close to the h100i direction. It was found that the individual subgrains, on average, are subjected to a reduction of the elastic strain with respect to the mean elastic strain of the grain. The walls are equivalently subjected to an increased elastic strain. The distribution of the elastic strains between the individual subgrains is found to be wider than the distribution of strains within the individual subgrains. The average properties are consistent with a composite type ofmodel. The details, however, show that present understanding of asymmetrical line broadening have to be reconsidered. Based on continuous deformation experiments, it is found that the dislocation patterning takes place during the deformation, and that a subgrain structure appears from the moment where plastic deformation is detected. By investigating samples under stress relaxation conditions, and unloading, it is found that the overall dislocation structure only depends on the maximum obtained flow stress. However, some changes in orientation and internal strain distribution between the subgrains were observed after the unloading. An in-situ stepwise straining experiment of a pre-deformed sample was performed, allowing for investigation of individual subgrains during straining. The result indicates that the cell refinement process generally does not take place through simple subgrain breakups. Surprisingly, the dislocation structure shows intermittent behavior, with subgrains appearing and disappearing with increasing strain, suggesting a dynamical development of the structure.

Jakobsen, Bo

2006-01-01

71

Scaling properties of sea ice deformation during winter and summer  

Science.gov (United States)

We investigate sea ice deformation observed with ice drifting buoy arrays during two field campaigns. Ice Station POLarstern [ISPOL], deployed in the western Weddell Sea during November 2004 to January 2005, included a study of small-scale (sub-synoptic) variability in sea ice velocity and deformation using an array of 24 buoys. Upon deployment the ISPOL buoy array measured 70 km in both zonal and meridional extent, and consisted of sub-arrays that resolved sea ice deformation on scales from 10 to 70 km. The Sea Ice Experiment: Dynamic Nature of the Arctic (SEDNA) used two nested arrays of six buoys each as a backbone for the experiment, that were deployed in late March 2007. The two arrays were circular with diameter 140 km and 20 km. ISPOL and SEDNA provide insight into the scaling properties of sea ice deformation over scales of 10 to 200 km during early Astral summer and late Boreal winter. The ISPOL and SEDNA arrays were split into sets of sub-arrays with varying length scales. We find that variance of divergence decreases as the length scale increases. The mean divergence for each length scale set follows a log-linear scaling relationship with length scale. This is an independent verification of a previous result of Marsden, Stern, Lindsay and Weiss (2004). This scaling is indicative of a fractal process. Deformation occurs at linear features (cracks, leads and ridges) in the ice pack, that are distributed with scales that range from meter to hundreds of kilometers in length. The magnitude of deformation at these linear features varies by two orders of magnitude across scales. We demonstrate that the deformation at all these scales is important in the mass balance of sea ice. Which has important implications for the design of sea ice deformation monitoring systems.

Hutchings, J. K.; Heil, P.; Roberts, A.

2009-12-01

72

Improvement of mechanical properties after superplastic deformation of silicon nitride  

Energy Technology Data Exchange (ETDEWEB)

Fine and uniform powder of {beta}-silicon nitride was liquid phase sintered by hot-pressing at 1700 C. Deformation behavior was investigated under compressive stress at 1500 - 1600 C. The material deformed at a strain rate, 1-7 x 10{sup -4} /s. under a pressure of 10-100 MPa at 1550 C. Strain hardening was not observed even at slow deformation rate because of the absence of appreciable dynamic grain growth. The strength and fracture toughness of as-hot-pressed materials was 793 MPa and 2.8 MPa.m{sup 1/2}, respectively. The properties were improved by the deformation to 912 MPa and 3.5 MPa.m{sup 1/2}, respectively. Further improvement was achieved by the annealing at 1700 C for 30 min. The bending strength and fracture toughness increased to 982 MPa and 3.7 MPa.m{sup 1/2}, respectively, by slight grain growth. Present work provides a process to produce complex-shaped components by superplastic deformation at low temperatures and to improve the mechanical properties by further heat treatment. (orig.)

Nishimura, T.; Zhan, G.-D.; Mitomo, M. [National Inst. for Research in Inorganic Materials, Tsukuba, Ibaraki (Japan); Sato, H. [Tokuyama Research Lab., Tokuyama Corp., Yamaguchi (Japan)

1999-07-01

73

Octupole correlations in 143 Ba and 147 Pr  

International Nuclear Information System (INIS)

High spin states in neutron-rich odd-Z 143,145 Ba nuclei have been investigated from the study of prompt ?-rays in the spontaneous fission of 252 Cf. Alternating parity bands are identified for the first time in 145 Ba and extended in 143 Ba. A new side band with equal, constant dynamic and kinematic moments of inertia equal to the rigid body value, as found in superdeformed bands, is discovered in 145 Ba. Enhanced E1 transitions between the negative- and positive-parity bands in these nuclei give evidence for strong octupole deformation in 143 Ba and in 145 Ba. These collective bands show competition and co-existence between symmetric and asymmetric shapes in 145 Ba. The first evidence is found for crossing M1 and E1 transitions between the s = +i and s = -i doublets in 143 Ba. Neutron-rich 147 Pr also was studied in the spontaneous fission of 252 Cf. Possible parity doublets observed in 147 Pr with N = 88 indicate that neutron-rich 59147 Pr88 nucleus exhibits strong octupole correlations like those observed in the 58146 Ce88 core. (authors)

2000-01-01

74

Deformation bands in porous sandstones their microstructure and petrophysical properties  

Energy Technology Data Exchange (ETDEWEB)

Deformation bands are commonly thin tabular zones of crushed or reorganized grains that form in highly porous rocks and sediments. Unlike a fault, typically the slip is negligible in deformation bands. In this dissertation the microstructure and petrophysical properties of deformation bands have been investigated through microscopy and numerical analysis of experimental and natural examples. The experimental work consists of a series of ring-shear experiments performed on porous sand at 5 and 20 MPa normal stresses and followed by microscopic examination of thin sections from the sheared samples. The results of the ring-shear experiments and comparison of them to natural deformation bands reveals that burial depth (level of normal stress in the experiments) and the amount of shear displacement during deformation are the two significant factors influencing the mode in which grains break and the type of shear zone that forms. Two end-member types of experimental shear zones were identified: (a) Shear zones with diffuse boundaries, which formed at low levels of normal stress and/or shear displacement; and (b) Shear zones with sharp boundaries, which formed at higher levels of normal stress and/or shear displacement. Our interpretation is that with increasing burial depth (approximately more than one kilometer, simulated in the experiments by higher levels of normal stress), the predominant mode of grain fracturing changes from flaking to splitting; which facilitates the formation of sharp-boundary shear zones. This change to grain splitting increases the power law dimension of the grain size distribution (D is about 1.5 in sharp boundary shear zones). Based on our observations, initial grain size has no influence in the deformation behavior of the sand at 5 MPa normal stresses. A new type of cataclastic deformation band is described through outcrop and microscopic studies; here termed a 'slipped deformation band'. Whereas previously reported cataclastic deformation bands are characterized by strain hardening, these new bands feature a central slip surface, which indicates late strain softening. They lack the characteristic compaction envelop, and are typified by higher porosity and lower permeability than previously-described cataclastic deformation bands. Intense background fracturing of the host rock and significant initial porosity are considered to be important in creating these newly-discovered deformation bands. In a related study, we investigate, for millimeter- wide deformation bands, the scale limitation inherent in laboratory measurements of porosity and permeability. The scale limitations imposed by the deformation band relative to the physical sample size motivated us to develop a new method for determining porosity and permeability based on image processing. While plug measurements measure the effective permeability across a 25.4 mm (1 inch) long sample, which includes both host rock and deformation band, the method presented here provides a means to estimate porosity and permeability of deformation band on microscale. This method utilizes low-order (one- and two orders) spatial correlation functions to analyze high-resolution, high-magnification backscatter images, to estimate the porosity and specific surface area of the pore-grain interface in the deformed sandstones. Further, this work demonstrates the use of a modified version of the Kozeny-Carmen relation to calculate permeability by using porosity and specific surface area obtained through the image processing. The result shows that permeability difference between the band and the host rock is up to four orders of magnitude. Moreover, the porosities and permeabilities estimated from image processing are lower than those obtained from their plug measurements; hence the traditional laboratory measurements have been overestimating permeability because of the previously-unrecognized scale problem. In addition, the image processing results clearly show that, as a result of microstructural variation, both porosity and permeability vary along the leng

Torabi, Anita

2007-12-15

75

Improving the deformation properties of plugging materials  

Energy Technology Data Exchange (ETDEWEB)

The VNIIKRneft' has conducted comprehensive studies to investigate the effect of different grades of asbestos (depending on the volume of additives) on the physical-mechanical properties of plugging stone prepared from special cement ShPTsS-120 based on Konstantinovskiy and Zhdanov slag. The experiments used chrysotile-asbestos of different brands (5th, 6th, 7th and some other grades) and groups according to the degree of fluffing up. In order to prevent cracking, it is necessary to add to the plugging cements based on Zhdanov slag, up to 5% chrysotile-asbestos of brand 7-450 d.r. At the same time it is necessary to treat this solution at the well with plasticizers, since in this case the ultimate strength for compression, bending, the lambda=upsilon /sub co/ /upsilon /sub be/ ratio and the impact resistance are the best. For example, lambda=2.01, which is less than 2.6 for the plugging stone of low brittleness, where the impact stability in this case is significant and equals 1337 J/m/sup 2/.

Parinov, P.F.

1980-01-01

76

The electrochemical properties of the cyclic deformed passive metals  

Energy Technology Data Exchange (ETDEWEB)

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)

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

77

Deformation behavior and mechanical properties of amyloid protein nanowires.  

Science.gov (United States)

Amyloid fibrils are most often associated with their pathological role in diseases like Alzheimer's disease and Parkinson's disease, but they are now increasingly being considered for uses in functional engineering materials. They are among the stiffest protein fibers known but they are also rather brittle, and it is unclear how this combination of properties affects the behavior of amyloid structures at larger length scales, such as in films, wires or plaques. Using a coarse-grained model for amyloid fibrils, we study the mechanical response of amyloid nanowires and examine fundamental mechanical properties, including mechanisms of deformation and failure under tensile loading. We also explore the effect of varying the breaking strain and adhesion strength of the constituent amyloid fibrils on the properties of the larger structure. We find that deformation in the nanowires is controlled by a combination of fibril sliding and fibril failure and that there exists a transition from brittle to ductile behavior by either increasing the fibril failure strain or decreasing the strength of adhesion between fibrils. Furthermore, our results reveal that the mechanical properties of the nanowires are quite sensitive to changes in the properties of the individual fibrils, and the larger scale structures are found to be more mechanically robust than the constituent fibrils, for all cases considered. More broadly, this work demonstrates the promise of utilizing self-assembled biological building blocks in the development of hierarchical nanomaterials. PMID:23290516

Solar, Max; Buehler, Markus J

2012-11-28

78

Deformation behavior and mechanical properties of amyloid protein nanowires.  

UK PubMed Central (United Kingdom)

Amyloid fibrils are most often associated with their pathological role in diseases like Alzheimer's disease and Parkinson's disease, but they are now increasingly being considered for uses in functional engineering materials. They are among the stiffest protein fibers known but they are also rather brittle, and it is unclear how this combination of properties affects the behavior of amyloid structures at larger length scales, such as in films, wires or plaques. Using a coarse-grained model for amyloid fibrils, we study the mechanical response of amyloid nanowires and examine fundamental mechanical properties, including mechanisms of deformation and failure under tensile loading. We also explore the effect of varying the breaking strain and adhesion strength of the constituent amyloid fibrils on the properties of the larger structure. We find that deformation in the nanowires is controlled by a combination of fibril sliding and fibril failure and that there exists a transition from brittle to ductile behavior by either increasing the fibril failure strain or decreasing the strength of adhesion between fibrils. Furthermore, our results reveal that the mechanical properties of the nanowires are quite sensitive to changes in the properties of the individual fibrils, and the larger scale structures are found to be more mechanically robust than the constituent fibrils, for all cases considered. More broadly, this work demonstrates the promise of utilizing self-assembled biological building blocks in the development of hierarchical nanomaterials.

Solar M; Buehler MJ

2013-03-01

79

Microstructure, properties and hot deformability of the new maraging steels  

Directory of Open Access Journals (Sweden)

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.

S.J. Pawlak; W. Zalecki

2008-01-01

80

Octupole degree of freedom for the critical-point candidate nucleus $^{152}$Sm in a reflection-asymmetric relativistic mean-field approach  

CERN Document Server

The potential energy surfaces of even-even $^{146-156}$Sm are investigated in the constrained reflection-asymmetric relativistic mean-field approach with parameter set PK1. It is shown that the critical-point candidate nucleus $^{152}$Sm marks the shape/phase transition not only from U(5) to SU(3) symmetry, but also from the octupole-deformed ground state in $^{150}$Sm to the quadrupole-deformed ground state in $^{154}$Sm. By including the octupole degree of freedom, an energy gap near the Fermi surface for single-particle levels in $^{152}$Sm with $\\beta_2 = 0.14 \\sim 0.26$ is found, and the important role of the octupole deformation driving pair $\

Zhang, W; Zhang, S Q; Meng, J; 10.1103/PhysRevC.81.034302

2010-01-01

 
 
 
 
81

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.

1995-01-01

82

Evidence for octupole vibration in the superdeformed well of {sup 190}Hg from eurogam  

Energy Technology Data Exchange (ETDEWEB)

Gammasphere experiments in 1993-94 brought to light the existence of an excited superdeformed (SD) band in {sup 190}Hg 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 {approximately} 150 and A {approximately} 190 regions of superdeformation. Although M1 transitions between signature-partner SD bands were previously observed in {sup 193}Hg, no such mechanism was available to explain the situation in the even-even nucleus {sup 190}Hg, 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 ({approximately}0.05% of the {sup 190}Hg channel) and also partly, we believed, to the angular distributions of the transitions, which were peaked near 90 degrees, where Gammasphere had few detectors.

Crowell, B.; Carpenter, M.P.; Janssens, R.V.F. [and others

1995-08-01

83

Some aspects of reflection asymmetric deformations in nuclei  

International Nuclear Information System (INIS)

[en] The nuclear shape in the intrinsic frame is studied using the Strutinsky method. Various potentials (Nilsson, folded Yukawa and Woods-Saxon) are used for the microscopic part, and the macroscopic part is described as a liquid drop with either a sharp or a smooth surface. Special attention is paid to the possibility of octupole deformed ground states. The consequences of octupole deformations for the rotational behaviour are investigated using the cranking model. It is particularly shown that octupole deformation may supress the backbending in some nuclei. (author)

1984-01-01

84

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

Energy Technology Data Exchange (ETDEWEB)

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.

Landgraf, F.J.G. E-mail: landgraf@ipt.br; Emura, M.; Ito, K.; Carvalho, P.S.G

2000-06-02

85

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

International Nuclear Information System (INIS)

[en] 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

2000-06-02

86

Comprehensive evidences of octupole vibration in $^{158}Gd$  

CERN Document Server

Comprehensive evidences of the SU(3 limit in the spdf interacting boson model, a dynamical symmetry describing octupole vibration in rotational nucleus, are found in the spectrum, E2 and E1 transition rates, and relative intensities in $^{158}$Gd. This gives a good example of rotational nucleus with octupole vibration in rare-earth region.

Long, G L; Zhao, E G

1999-01-01

87

Transient deformation properties of Zircaloy for LOCA simulation. Final report  

International Nuclear Information System (INIS)

[en] 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

1978-01-01

88

Excitation of octupole, beta- and gamma-vibration band levels of 238U by inelastic neutron scattering  

International Nuclear Information System (INIS)

[en] Experimental data on inelastic neutron scattering are analyzed in a Hauser-Feshbach-Moldauer approach with a coupled-channel estimates of the direct reaction contribution. For the direct excitation of the ground state rotational band levels with J?=0+, 2+, 4+, 6+, 8+ the rigid rotator model was used, whereas for the direct excitation of members of the ?-, ?- (K?=02+, 03+, 2+) and first octupole band (K?=0-) a soft-deformable rotator model was used. Quadrupole, octupole, hexadecapole and gamma-deformation parameters are defined by consistent analysis of excited rotational-vibrational band structures and excitation cross sections of the relevant levels. Structures evident in measured neutron emission spectra for En?1-6 MeV are correlated with excitation of levels of K?=0- and K?=02+, 03+, 2+ bands

2006-01-09

89

Some Electronic Properties of Metals through q-Deformed Algebras  

CERN Document Server

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.

Tristant, Damien

2013-01-01

90

Quadrupole-deformed and octupole collective bands in $^{228}Ra$  

CERN Document Server

Spins and parities for collective states in $^{228}$Ra have been determined from conversion electron measurements with a mini-orange $\\beta$ spectrometer. The fast-timing $\\beta\\gamma\\gamma(t)$ method has been used to measure lifetimes of T$_{1/2}$=550(20) ps and 181(3) ps for the 2$^+_1$ and 4$^+_1$ members of the K=0$^+$ band, and T$_{1/2}

Gulda, K; Aas, A J; García-Borge, M J; Burke, D G; Fogelberg, B; Gietz, H; Grant, I S; Hagebø, E; Hill, P; Hoff, P; Kaffrell, N; Kurcewicz, W; Lindroth, A; Løvhøiden, G; Martínez, T; Mattsson, S; Naumann, R A; Nybø, K; Nyman, G H; Rubio, B; Sánchez-Vega, M; Taín, J L; Taylor, R B E; Tengblad, O; Thorsteinsen, T F

1998-01-01

91

Thermostatistical properties of q-deformed bosons trapped in a D-dimensional power-law potential  

Science.gov (United States)

The thermostatistical properties of an ideal gas of q-deformed bosons trapped in a D-dimensional power-law potential are studied, based on the q-deformed Bose-Einstein distribution. The effects of q-deformation on the properties of the system are discussed. It is shown that q-deformed bosons (q \

Su, Guozhen; Chen, Jincan; Chen, Lixuan

2003-10-01

92

Heart - Shaped Nuclei: Condensation of Rotational Aligned Octupole Phonons  

CERN Multimedia

The strong octupole correlations in the mass region $A\\approx 226$ are interpreted as rotation-induced condensation of octupole phonons carrying three units of angular momentum aligned with the rotational axis. The condensation represents a quantum phase transition. Discrete phonon energy and parity conservation generate oscillations of the rotational sequences with positive and negative parity. The phonon condensate co-rotates with quadrupole shape forming a rotating heart shape. The coupling between the quadrupole and octupole modes reaches a maximum in the $N\\approx 136$ isotones, approaching the limit of a static heart shape.

Frauendorf, S

2007-01-01

93

Influence of Plastic Deformation on the Properties of 6066 Heat Treatable Aluminum Alloys  

Directory of Open Access Journals (Sweden)

Full Text Available The aims of this work are to (1) study the influence of plastic deformation on the properties of 6066 aluminum alloy; (2) study the effect of deformation on the age hardening of these alloys; (3) study the recovery of these defects from the samples. These effects were investigated in terms of microstructure using positron annihilation spectroscopy (PAS) analysis and mechanical properties by hardness measurements. Dislocations facilitate nucleation of precipitates. At first sight, deformed specimens had lower hardness as compared to non-deformed ones, and as the deformation increase, the hardness decreases. Another output of the mechanical test was the increase in hardness in the specimens after artificial aging with an increase in percent deformation.

Emad Abdelraouf BADAWI; Mmdouh ABDEL-NASER; Alaa Aldeen AHMED

2013-01-01

94

Effects of tensile plastic deformation on the magnetic properties of AISI 4140 steel  

Energy Technology Data Exchange (ETDEWEB)

The magnetic properties of a number of specimens of AISI 4140 alloy steel were measured after they had been subjected to different amount of tensile plastic deformation. Results showed that while some magnetic parameters such as coercivity and initial permeability varied in a simple manner with plastic deformation, others such as anhysteretic permeability and maximum differential permeability were largely insensitive to the deformation. These conclusions have implications for the separation of elastic and plastic strain from magnetic nondestructive evaluation measurements.

Jiles, D.C.; Utrata, D.

1987-09-01

95

Convergence properties of the q-deformed binomial distribution  

Directory of Open Access Journals (Sweden)

Full Text Available We consider the $q$-deformed binomial distribution introduced by{sc S. C. Jing:} {it The {$q$}-deformed binomial distribution and its asymptotic behaviour,}J. Phys. A {f 27} (2) (1994), 493--499and{sc W. S. Chung} et al: {it {$q$}-deformed probability and binomial distribution,} Internat. J. Theoret. Phys.{f 34} (11) (1995), 2165--2170and establish several convergence results involvingthe Euler and the exponential distribution; some of them are $q$-analogues of classical results.

Martin Zeiner

2010-01-01

96

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

97

Magnetic properties of ?-vibrational bands of deformed nuclei  

International Nuclear Information System (INIS)

The formula for finding of the gyromagnetic ratios (gK - gR)2 is deduced for deformed rare earth nuclei. The gyromagnetic ratio is calculated on the intraband transitions in the ?-vibrational bands of deformed nuclei. The expression for calculating of the magnetic moments for nuclei under consideration is obtained in the framework of the adiabatic approximation. The data about the intraband ?-transitions, the gyromagnetic ratios and the magnetic moments are given for 11 deformed rare earth nuclei. The basic error of the determination of the gyromagnetic ratios is caused by errors related with the intensities of intraband ?-transitions I?1 and I?2. The comprehensive analysis of obtained results is performed

1999-01-01

98

IBM-2 description of M1 properties in deformed nuclei  

International Nuclear Information System (INIS)

[en] Results of schematic calculations are presented in which various terms breaking F-spin symmetry are considered in the hamiltonian of the neutron-proton interacting boson model (IBM-2). Specific attention is paid to the effect of F-spin symmetry breaking on ? ? ground and ? ? ? M1 transitions in deformed nuclei. A comparison with available M1 data in the rare-earth nuclei is presented. The constraints implied by these data on the form of the IBM-2 hamiltonian in well-deformed nuclei are discussed. (orig.)

1988-01-11

99

IBM-2 description of M1 properties in deformed nuclei  

Energy Technology Data Exchange (ETDEWEB)

Results of schematic calculations are presented in which various terms breaking F-spin symmetry are considered in the hamiltonian of the neutron-proton interacting boson model (IBM-2). Specific attention is paid to the effect of F-spin symmetry breaking on ..gamma.. -> ground and ..gamma.. -> ..gamma.. M1 transitions in deformed nuclei. A comparison with available M1 data in the rare-earth nuclei is presented. The constraints implied by these data on the form of the IBM-2 hamiltonian in well-deformed nuclei are discussed.

Van Isacker, P.; Lipas, P.O.; Helimaeki, K.; Koivistoinen, I.; Warner, D.D.

1988-01-11

100

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

Science.gov (United States)

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.

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

2013-08-01

 
 
 
 
101

Evaluation of fracture properties of cold deformed 450 YS TMCP steel  

Energy Technology Data Exchange (ETDEWEB)

In the present study, 450 YS TMCP steel of 20 mm thickness was used to characterize the cold deformation capacity and respective mechanical and fracture toughness properties. The present work is part of a joint research project by the Dillinger Huette and GKSS Research Center on the cold deformation, weldability and various fracture aspects of the 450 YS TMCP steel. The paper, however, only refers to the investigation on cold deformation and respective fracture characteristics of the 450 YS TMCP steel. In particular, it is aimed at understanding the effect of cold deformation and anisotropy on the fracture behavior through tensile, Charpy-V notch impact, CTOD and wide-plate testing as well as via microstructural examination. As part of the program, tests were performed at RT, {minus}40 C and {minus}80 C on specimens machined from plates in six conditions, namely: (1) as-rolled (0% CD), (2) 5% cold deformed (pre-strained in tension) (5% CD), (3) 10% cold deformed (pre-strained in tension) (10% CD), (4) as-rolled + SR (580 C for 1 hour) (0% CD + SR), (5) 5% cold deformed + SR (5% CD + SR) and (6) 10% cold deformed + SR (10% CD + SR). An increasing degree of cold deformation increased both YS and TS combined with a reduction in ductility and toughness. The shift of the CVN transition curve was of the same order as experienced for normalized and Q+T steels. Thanks to the excellent as-rolled properties, even after 10% cold deformation, impact requirements were satisfied at least down to {minus}50 C. The YS to TS ratio was increased and was highest with the specimen axis parallel to the rolling and straining direction. The SR helped to regain a ratio of 0.90 even for 10% cold deformation.

Dobi, D.; Kocak, M.; Petrovski, B.I. [GKSS Research Center, Geesthacht (Germany). Inst. of Materials Research; Hanus, F. [Dillinger Huette AG, Saar (Germany). Welding Lab.

1994-12-31

102

Magnetic properties of odd-odd deformed nuclei  

International Nuclear Information System (INIS)

Magnetic moments and M1 transition probabilities depend on the parameters gsub(R), gsub(?sub(p)), and gsub(?sub(n)) in odd-odd deformed nuclei. The parameter gsub(R) can be obtained from an intraband branching ratio and a magnetic moment. Available data are analyzed and compared with predictions of the unified model. (Auth.)

1977-08-22

103

Mechanical properties of hot deformed Inconel 718 and X750  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: Variations of a flow stress vs. true strain illustrate behavior of material during plastic deformation. Stress-strain relationship is generally evaluated by a torsion, compression and tensile tests.Design/methodology/approach: Compression tests were carried out on precipitations hardenable nickel based superalloys of Inconel 718 and X750 at constant true strain rates of 10-4, 4x10-4s-1 within temperature through which precipitation hardening phases process occurred (720-1150°C) using thermomechanical simulator Gleeble and dilatometer Baehr 850D/L equipped with compression unit. True stress-true strain curves analysis of hot deformed alloys were described.Findings: On the basis of received flow stress values activation energy of a high-temperature deformation process was estimated. Mathematical dependences (?pl -T i ?pl - ?) and compression data were used to determine material’s constants. These constants allow to derive a formula that describes the relationship between strain rate (?), deformation temperature (T) and flow stress ?pl.Research limitations/implications: Study the flow stress will be continued on the samples after the aging process.Practical implications: The results of high-temperature deformation of the examined Inconel alloys may possibly find some practical use in the workshop practice to predict a flow stress values, but only within particular temperature and strain rate ranges. The results of the study can be used in the aerospace industry to produce blades for jet engines.Originality/value: The results of the study can be used in the aerospace industry to produce blades for jet engines.

A. Nowotnik; P. P?drak; J. Sieniawski; M. Góral

2012-01-01

104

Two-octupole-phonon states in 146,148Gd  

International Nuclear Information System (INIS)

The so-called 'two-octupole-phonon states' in 146,148Gd are theoretically analyzed by using the Dyson boson mapping method. In our analyses, the free ground state of 146Gd is treated as doubly closed shell since Z=64 is rather good subshell closure. The starting collective multi-phonon space that we take consists of collective octupole phonons and collective monopole pairing phonons for 146Gd. Additionally correlated particle-pair modes with J?0 are included in the multi-phonon space for 148Gd. The effective Hamiltonian used is constituted by a Woods-Saxon-type single-particle potential, an octupole-octupole force for particle-hole modes and a surface-delta interaction for particle-pair and hole-pair modes. The numerical calculation can considerably well reproduce the octupole collectivity shown by experiments for 146,148Gd. It is shown that the Dyson boson mapping method is useful for such a complicated system as 148Gd. (author).

1996-01-01

105

Magnetic properties of deformed dipole bands in 110, 112Te  

Science.gov (United States)

A lifetime analysis using the Doppler-shift attenuation method has been performed on the Tellurium isotopes 110, 112Te. The experiment was performed using the Gammasphere array in conjunction with the MICROBALL charged-particle detector. Three strongly coupled bands were previously established in 110, 112Te which were observed up to unusually high spins. In the current experiment, it has been possible to extract lifetime measurements using a Doppler broadened lineshape analysis on one of the ?I=1 band structures in 110Te. In contrast to similar ?I=1 structures in other nuclei in this mass region, the extracted B(M1) values did not rapidly decrease with increasing angular momentum. Instead, the strongly coupled band in 110Te represents a deformed 1p-1h structure, rather than a weakly deformed structure showing the shears mechanism.

Evans, A. O.; Paul, E. S.; Boston, A. J.; Chantler, H. J.; Chiara, C. J.; Devlin, M.; Fletcher, A. M.; Fossan, D. B.; La Fosse, D. R.; Lane, G. J.; Lee, I. Y.; Macchiavelli, A. O.; Nolan, P. J.; Sarantites, D. G.; Sears, J. M.; Semple, A. T.; Smith, J. F.; Starosta, K.; Vaman, C.; Ragnarsson, I.; Afanasjev, A. V.

2006-07-01

106

Transient deformation properties of Zircaloy for LOCA simulation. Final report  

Energy Technology Data Exchange (ETDEWEB)

This experimental data report is Volume 4 of a series of 5 volumes describing the oxidation and deformation rate behavior of Zircaloy cladding under simulated LOCA conditions. It contains listings of strain versus stress, time, and temperature evaluated from the numerical constitutive relationships and the original data used to develop them. This volume also contains listings of the ramp load, pressure, and temperature test data from both current and previous phases of the series, as well as material describing applications of the data.

Hann, C. R.; Mohr, C. L.; Busness, K. M.; Olson, N. J.; Reich, F. R.; Stewart, K. B.

1980-05-01

107

A study of plastic deformation during axisymmetric forward spiral extrusion and its subsequent mechanical property changes  

Science.gov (United States)

Axisymmetric forward spiral extrusion (AFSE) accumulates large strains in its sample while extruding it through a die with engraved spiral grooves. A three-dimensional finite element model of AFSE has been developed using ABAQUS to investigate the deformation mode in detail, including the effect of groove geometry and the heterogeneity of plastic deformation. The numerical results demonstrated that the strain distribution in the AFSE sample cross section is linear in the radial direction within a concentric core while the distribution, outside the core, in the vicinity of the grooves is non-linear and non-axisymmetric. Mechanical properties and grain structure changes of the deformed sample were investigated. Improvements of mechanical properties in the processed samples can be attributed to the domination of the shear deformation mode in a plane normal to the extrusion axis and consequently the elongation of grains in the tangential direction.

Farhoumand, A.; Khoddam, S.; Hodgson, P. D.

2012-12-01

108

Structural and electronic properties of a carbon nanotorus: Effects of delocalized and localized deformations  

International Nuclear Information System (INIS)

The bending of a carbon nanotube is studied by considering the structural evolution of a carbon nanotorus from elastic deformation to the onset of the kinks and eventually to the collapse of the walls of the nanotorus. The changes in the electronic properties due to delocalized deformations are contrasted with those due to localized deformations to bring out the subtle issue underlying the reason why there is only a relatively small reduction in the electrical conductance in the former case even at large bending angles, while there is a dramatic reduction in the conductance in the latter case at relatively small bending angles

2001-07-15

109

Structural and Electronic Properties of a Carbon Nanotorus Effects of Delocalized Vs Localized Deformations  

CERN Document Server

The bending of a carbon nanotube is studied by considering the structural evolution of a carbon nanotorus from elastic deformation to the onset of the kinks and eventually to the collapse of the walls of the nanotorus. The changes in the electronic properties due to {\\it non-local} deformation are contrasted with those due to {\\it local} deformation to bring out the subtle issue underlying the reason why there is only a relatively small reduction in the electrical conductance in the former case even at large bending angles while there is a dramatic reduction in the conductance in the latter case at relatively small bending angles.

Liu, L; Wu, S Y; Liu, Lei

2000-01-01

110

Structural and electronic properties of a carbon nanotorus: Effects of delocalized and localized deformations  

Energy Technology Data Exchange (ETDEWEB)

The bending of a carbon nanotube is studied by considering the structural evolution of a carbon nanotorus from elastic deformation to the onset of the kinks and eventually to the collapse of the walls of the nanotorus. The changes in the electronic properties due to delocalized deformations are contrasted with those due to localized deformations to bring out the subtle issue underlying the reason why there is only a relatively small reduction in the electrical conductance in the former case even at large bending angles, while there is a dramatic reduction in the conductance in the latter case at relatively small bending angles.

Liu, Lei; Jayanthi, C. S.; Wu, S. Y.

2001-07-15

111

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

1988-01-01

112

Effect of severe plastic deformation mode on microstructure and mechanical properties of AM60 magnesium alloy  

International Nuclear Information System (INIS)

[en] Investigation results are reported for microstructure and mechanical properties of a magnesium base alloy AM60 (Mg-6 mas.% Al-0.13 mas.%Mn) subjected to severe plastic deformation (SPD). A consideration is given to microstructure evolution on heating specimens produced by equal channel angular pressing and torsional deformation. The results of tensile testing at room and elevated temperatures are presented for specimens after SPD[ru] ???????????? ?????????? ???????????? ?????????????? ? ???????????? ??????? ?????????? ?????? ??60 (Mg-6 ???.% Al-0.13 ???.%Mn), ????????????? ??????????? ???????????? ?????????? (???). ??????????? ???????? ?????????????? ??? ??????? ????????, ?????????? ?????????????? ??????? ???????????? ? ??????????? ?????????. ????????? ?????????? ???????????? ????????? ?? ?????????? ??? ????????? ? ?????????? ???????????? ???????? ????? ???

2004-01-01

113

Mechanical properties of the Fe-Cr-Co system alloys in cast and deformed states  

International Nuclear Information System (INIS)

[en] Mechanical properties of the KhK15 and KhK23 type alloys (in the cast and deformed states) depending on chemical composition, test temperature, quenching and normalization are studied. It is shown that the temperature of the preliminary quenching, the test temperature and the alloy structural state affect considerably the mechanical properties

1979-01-01

114

Octupole signatures in {sup 124,125}Ba  

Energy Technology Data Exchange (ETDEWEB)

The {gamma} decay of the nuclei {sup 124,125}Ba has been investigated with the EUROBALL array, using the reaction {sup 64}Ni+{sup 64}Ni at E{sub beam} = 255 and 261 MeV. Six new E1 transitions have been found in the nucleus {sup 125}Ba, suggesting a significant role of octupole correlations in the origin of its parity doublets. The J{sup {pi}} = 3{sup -} level of the nucleus {sup 124}Ba 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.

Mason, P [Dipartimento di Fisica, Universita di Milano and INFN, Sezione di Milano (Italy); Benzoni, G [Dipartimento di Fisica, Universita di Milano and INFN, Sezione di Milano (Italy); Bracco, A [Dipartimento di Fisica, Universita di Milano and INFN, Sezione di Milano (Italy)] [and others

2005-10-01

115

An interacting boson model description of octupole states in nucleic  

Science.gov (United States)

The IBM-1 + f-boson model is described and systematically applied to the nuclei 154Sm, 156Gd, 158Gd, 158Dy, 162Dy, 168Er, 172Yb, 178Hf, and 182W. Reasonable agreement with available energies and B( E3) transition rates is obtained in all cases except 162Dy, which has the anomalous octupole band order K? = 2 -, 0 -, 1 -. This energy ordering of K- bands cannot be obtained within the present model. The parameter trends show considerable variation, indicating that the underlying fermionic subshell structure is very important in octupole states.

Barfield, A. F.; Barrett, B. R.; Wood, J. L.; Scholten, O.

1988-03-01

116

Mechanical property of superplastic-deformed ceramics by micro-indentation method  

Energy Technology Data Exchange (ETDEWEB)

A neutron irradiation test on superplastic ceramic materials at high temperature has been proposed as an innovative basic research on high-temperature engineering using the High Temperature Engineering Test Reactor (HTTR). We investigated mechanical properties, such as the hardness and Young's modulus, of ceramic specimens after superplastic deformation. The tested material was 3Y-TZP (3mol% Yttria stabilized Tetragonal Zirconia Polycrystal) which is one of the representative superplastic ceramics. The properties were measured by a microindentation method. We also studied the relationship between crystal microstructures and the mechanical properties of deformed 3Y-TZP by scanning electron microscope (SEM). The indentation test showed that the mechanical properties of the specimens were reduced to about 1/2 by 30% deformation and to about 1/4 by 150% deformation. The SEM images showed that average grain size and deviation of grain size of each specimen increased with increasing deformation. From both the results, it was analytically shown that the increasing of the grain size was thought to be one of the causes of the reduction of the mechanical properties. (author)

Shibata, Taiju; Ishihara, Masahiro; Takahashi, Tsuneo; Hayashi, Kimio [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Motohashi, Yoshinobu [Ibaraki Univ., Mito, Ibaraki (Japan)

2001-03-01

117

Parity splitting and E1/E2 branching in the alternating parity band of 240Pu from two-center octupole wave functions using supersymmetric quantum mechanics  

International Nuclear Information System (INIS)

An interpretation is suggested of the recently published experimental data on the alternating parity bands in 240Pu. The interpretation is based on the assumption that the main role in the description of the properties of the alternating parity bands plays the octupole mode which preserves the axial symmetry. The mathematical technique of the supersymmetric quantum mechanics is used for the realization of the model with the two-center octupole wave functions. A good description of the parity splitting and of the ratio of the dipole and quadrupole transitional moments is obtained for the first two bands.

2011-01-01

118

Strength of octupole correlations in the actinides: contrasting behavior in the isotones 237U and 239Pu  

International Nuclear Information System (INIS)

A study of high spin states in the odd-neutron isotones 239Pu and 237U is reported. Striking differences were found in the high-spin properties of rotational bands built on the 1/2+[631] ground states in these two nuclei. These differences mirror those observed in the even-even Pu and U immediate neighbors and appear to be related to the strength of octupole correlations.

2005-07-07

119

Nonclassical properties of a particle in a finite range trap: The f-deformed quantum oscillator approach  

Energy Technology Data Exchange (ETDEWEB)

A particle bounded in a potential with finite range is described by using an f-deformed quantum oscillator approach. Finite range of this potential can be considered as a controllable deformation parameter. The nonclassical quantum statistical properties of this deformed oscillator can be manipulated by nonlinearities associated to the finite range.

Davoudi Darareh, M., E-mail: m.davoudi@sci.ui.ac.i [Department of Physics, Faculty of Science, University of Isfahan, Hezar Jerib, Isfahan, 81746-73441 (Iran, Islamic Republic of); Bagheri Harouni, M., E-mail: m-bagheri@phys.ui.ac.i [Department of Physics, Faculty of Science, University of Isfahan, Hezar Jerib, Isfahan, 81746-73441 (Iran, Islamic Republic of)

2010-09-06

120

Nonclassical properties of a particle in a finite range trap: the f-deformed quantum oscillator approach  

CERN Document Server

A particle bounded in a potential with finite range is described by using an $f$-deformed quantum oscillator approach. Finite range of this potential can be considered as a controllable deformation parameter. The non-classical quantum statistical properties of this deformed oscillator can be manipulated by nonlinearities associated to the finite range.

Darareh, M Davoudi; 10.1016/j.physleta.2010.08.014

2012-01-01

 
 
 
 
121

Interplay between octupole and quasiparticle excitations in {sup 178}Hg and {sup 180}Hg  

Energy Technology Data Exchange (ETDEWEB)

Excited structures in the Z=80, {sup 178}Hg (N=98), and {sup 180}Hg (N=100) isotopes have been investigated with the Gammasphere spectrometer in conjunction with the recoil-decay tagging technique. The present data extend the previously known ground-state bands to higher spin and excitation energy. Negative parity bands with a complex decay towards the low spin states arising from both the prolate-deformed and the nearly spherical coexisting minima have been observed for the first time in both nuclei. It is shown that these sequences have characteristics in common with negative-parity bands in the heavier even-even Hg isotopes as well as in the Os and Pt isotones. These structures are interpreted as being associated at low spin with an octupole vibration which is crossed at moderate frequency by a shape driving, two-quasiproton excitation.

Kondev, F. G.; Janssens, R. V. F.; Carpenter, M. P.; Abu Saleem, K.; Ahmad, I.; Alcorta, M.; Amro, H.; Bhattacharyya, P.; Brown, L. T.; Caggiano, J. (and others)

2000-10-01

122

Structure and mechanical properties of hot deformed high-alloy ferritic steel  

International Nuclear Information System (INIS)

[en] In the paper are presented results of research on impact of parameters of hot plastic strain upon variations of mechanical properties and structure of the high-alloy ferritic steel, after the process of high temperature deformation. The tests were carried out at a torsion plastometer in a scope of temperatures 900-1150 oC with a rate 0.04; 0.35 and 3.5 s-1. determined. Relations between the process parameters and mechanical properties in plastometric torsion test are determined. There was disclosed an intensive process of structure refinement during a high temperature deformation. (author)

2004-01-01

123

Fifth-order aberrations in magnetic quadrupole-octupole systems  

Energy Technology Data Exchange (ETDEWEB)

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.

Ling, K.M.

1990-01-01

124

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

1988-01-01

125

Homogenized Elastic Properties of Graphene for Small Deformations  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, we provide the quantification of the linear and non-linear elastic mechanical properties of graphene based upon the judicious combination of molecular mechanics simulation results and homogenization methods. We clarify the influence on computed results by the main model features, such as specimen size, chirality of microstructure, the effect of chosen boundary conditions (imposed displacement versus force) and the corresponding plane stress transformation. The proposed approach is capable of explaining the scatter of the results for computed stresses, energy and stiffness and provides the bounds on graphene elastic properties, which are quite important in modeling and simulation of the virtual experiments on graphene-based devices.

Eduard Mareni?; Adnan Ibrahimbegovic; Jurica Sori?; Pierre-Alain Guidault

2013-01-01

126

Upper Mantle Tectonics: Three-Dimensional Deformation, Olivine Crystallographic Fabrics and Seismic Properties  

UK PubMed Central (United Kingdom)

Forward numerical models are used to investigate the effect of deformation regime on the development of olivinelattice-preferred orientations (LPO) and associated seismic anisotropy within continental deformation zones. LPO predictedto form by pure shear, simple shear, transpression, or transtension are compared to a database comprising ca. 200 olivineLPO from naturally deformed upper mantle rocks. This comparison suggests that simple shear or plane combinationsof simple and pure shear are probably the dominant deformation regimes in the upper mantle. Seismic properties,calculated using the modeled olivine LPO, suggest that seismic anisotropy data may carry information on the deformationregimes active in the lithospheric mantle, although not all deformation regimes are characterized by a distinct seismicanisotropy signal. Transtensional deformation in continental rift systems should result in fast S-wave polarization andP-wave propagation directions oblique to the rift trend within the extended lithospheric mantle. Simple shear (wrench)or transpression in vertical deformation zones and pure shear (horizontal extension) result in similar seismic anisotropy.Simple shear or widening--thinning shear may, however, induce obliquity between seismic and magnetotelluric electricalconductivity anisotropy data. Similarly, it is not possible to distinguish between simple shear or lengthening--thinning shear(plane transpression) in horizontal deformation zones (thrusts) and pure shear (vertical contraction=horizontal extension).In all cases, the polarization direction of the fast split S-wave and the fast P-wave direction parallels the flow direction, butthe anisotropy for both Pn- and S-waves is lower in horizontal structures than in vertical ones. Finally, several de...

Andrea Tommasi; Alain Vauchez

127

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

International Nuclear Information System (INIS)

[en] 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)

1986-01-01

128

Influence of deformation and heat treatment on structure, physical and mechanical properties of tungsten alloys  

International Nuclear Information System (INIS)

[en] Studied was the influence of deformation and heat treatment on the structure and properties of the W-Mo-Re system tungsten alloys, strengthened with HfC carbides. The dependence of the rupture strength on the sample diameter has been obtained. The alloy strength subject to the change of diameter within the same order has been worked out. Studied was the influence of intermediate annealings on the deformability and stratification aptitude of the wire during hot and cold drawing. Produced was some material, possessing high short-time and endurance strength limits. It also has a better plasticity at room and increased (up to 1.500 deg C) temperatures

1979-01-01

129

Effect of deformation and heat treatment on phase transformations and properties of titanium alloys  

International Nuclear Information System (INIS)

[en] Effects of deformation and heat treatment on phase transformations in VT22 and VT22M alloys were studied to reveal the structural factors controlling high strength of titanium alloys and to determine deformation and heat treatment conditions providing satisfactory plastic properties. It is recommended to work the materials in (?+?) phase field at 860 deg C before hardening heat treatment to prevent loss of ductility. It is found that the strength of both alloys is connected with a quantity ratio of ?- and ?-phases and is determined by their structure state

1982-01-01

130

Effect of deformation and subsequent tempering on the mechanical properties of 15Kh1M1F  

Energy Technology Data Exchange (ETDEWEB)

The effect of preliminary cold deformation by tension on the properties of 15Kh1M1F steel is studied under conditions of short-term and long-term high temperature loading. Ten percent cold-working hardening established to increase long-term strength of steel with ferrite-carbide structure and to decrease it in case of bainite structure. V-shaped curve of deformed metal long-term plasticity or its descending branch shift in the direction of shorter durabilities is compared with the deformed state. Post-deformation tempering approximates the metal properties to the original level.

Mints, I.I.; Shtejnberg, M.M.; Smirnova, A.P. (Vsesoyuznyj Nauchno-Issledovatel' skij Inst. Teplotekhnicheskij, Moscow (USSR))

1983-01-01

131

Thermostatistical properties of q-deformed bosons trapped in a D-dimensional power-law potential  

International Nuclear Information System (INIS)

The thermostatistical properties of an ideal gas of q-deformed bosons trapped in a D-dimensional power-law potential are studied, based on the q-deformed Bose-Einstein distribution. The effects of q-deformation on the properties of the system are discussed. It is shown that q-deformed bosons (q ? 1) possess many different characteristics from those of ordinary bosons, which include the condition that Bose-Einstein condensation (BEC) occurs, the critical temperature and the continuity of heat capacity

2003-10-10

132

Thermostatistical properties of q-deformed bosons trapped in a D-dimensional power-law potential  

Energy Technology Data Exchange (ETDEWEB)

The thermostatistical properties of an ideal gas of q-deformed bosons trapped in a D-dimensional power-law potential are studied, based on the q-deformed Bose-Einstein distribution. The effects of q-deformation on the properties of the system are discussed. It is shown that q-deformed bosons (q {ne} 1) possess many different characteristics from those of ordinary bosons, which include the condition that Bose-Einstein condensation (BEC) occurs, the critical temperature and the continuity of heat capacity.

Su Guozhen; Chen Jincan; Chen Lixuan [CCAST (World Laboratory), PO Box 8730, Beijing 100080 (China); Department of Physics, Xiamen University, Xiamen 361005 (China)

2003-10-10

133

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

Directory of Open Access Journals (Sweden)

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

Lembit KOMMEL; Mart SAARNA; Rainer TRAKSMAA; Igor KOMMEL

2012-01-01

134

Interacting boson model description of octupole states in nuclei  

Energy Technology Data Exchange (ETDEWEB)

The IBM-1+f-boson model is described and systematically applied to the nuclei /sup 154/Sm, /sup 156/Gd, /sup 158/Gd, /sup 158/Dy, /sup 162/Dy, /sup 168/Er, /sup 172/Yb, /sup 178/Hf, and /sup 182/W. Reasonable agreement with available energies and B(E3) transition rates is obtained in all cases except /sup 162/Dy, which has the anomalous octupole band order K/sup ..pi../ = 2/sup -/, 0/sup -/, 1/sup -/. This energy ordering of K/sup -/ bands cannot be obtained within the present model. The parameter trends show considerable variation, indicating that the underlying fermionic subshell structure is very important in octupole states. copyright 1988 Academic Press, Inc.

Barfield, A.F.; Barrett, B.R.; Wood, J.L.; Scholten, O.

1988-03-01

135

Deformation Properties of Forest Soils in Karelia Affected by "Freeze-Defrost" Cycles  

Directory of Open Access Journals (Sweden)

Full Text Available The impact of “freeze-defrost” cycles on the deformation properties of forest soils has been little studied. The layout of technological schemes of harvesting sites development in off-season periods (spring, fall) depends a lot on the formation of ruts when wood harvesting machinery passes. The study of processes occurring in forest soils affected by “freeze-defrost” cycles enables to justify the method of calculating rut depth depending on the number of machinery passes. The compression modulus of deformation, compressibility coefficient and relative compressibility coefficient of clay loam which was collected in the forest of the Republic of Karelia were determined in laboratory conditions. Forest soil samples underwent three “freeze-defrost” cycles. It has been determined clay loam deformation modulus after the first cycle reduces by 16% and after the second and third cycles it reduces by 18% and 25% respectively in relation to the value of deformation modulus before freezing. Compressibility coefficient increases by 18% after the first cycle, it increases by 22% after the second cycle and by 33% after the third one. The decrease of deformation modulus and the increase of clay loam compressibility coefficient are due to changes in the structure of forest soils under the influence of “freeze-defrost” cycles.

Ratjkova E. I.; Syunev V. S.,; Katarov V. K.

2013-01-01

136

The octupole giant resonance strength in 16O  

International Nuclear Information System (INIS)

[en] Angular distributions for polarized proton inelastic scattering cross sections along with the analysing power for the reaction 16O(p(pol),p')16O*(2-,8.88 MeV) at Esub(p)=42.5, 44.0 and 49.3 MeV have been measured. A semidirect reaction analysis augments the evidence for octupole giant resonance strength in the 30 to 50 MeV energy region. (Auth.)

1977-05-09

137

Octupole deformation in {sup 226}Th; Deformation octupolaire du {sup 226}Th  

Energy Technology Data Exchange (ETDEWEB)

Sources of {sup 230}U - resulting from the {beta}{sup -} decay of {sup 230}Pa produced in the reaction {sup 232}Th(p,3n) with 34 MeV protons - were purified and used to determine the half life of the 230.4 keV 1{sup -} state in {sup 226}Th. Using the Doppler shift method, following {alpha} decay of {sup 230}U, a value T{sub 1/2} = 3.5 {+-} 1.2 ps was determined. The half life of the 226.4 keV 4{sup +} state was also measured as T{sub 1/2} = 145 {+-} 20 ps. The absolute probabilities in Weisskopf units of the 230 keV and 158 keV {gamma} transitions depopulating the 1{sup -} state were determined as (2.50 {+-} 0.86) x 10{sup -3} and (4.54 {+-} 1.55) x 10{sup -3} respectively. Experimental values of the intrinsic dipole moment, D{sub 0}, and of D{sub 0}/Q{sub 0}, were determined as 0.27 {+-} 0.05 e.fm and (3.5 {+-} 1.0) x 10{sup -4} fm{sup -1}. These data have been compared with theories and experiment. (authors)

Liang, C.F. [Experimental Research Division, Inst. de Physique Nucleaire, Paris-11 Univ., 91 - Orsay (France); Paris, P. [Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse, 91 - Orsay (France); Sheline, R.K. [Florida State Univ., Tallahassee, FL (United States)] [and others

1999-11-01

138

Deformation properties of pharmaceutical excipients determined using an in-die and out-die method.  

UK PubMed Central (United Kingdom)

This study investigated deformation mechanisms of some commonly used pharmaceutical fillers, such as microcrystalline cellulose, lactose, dicalcium phosphate, isomalt and cornstarch, using a combination of the in-die and out-die method with the Heckel and Walker models. The tableting mixtures contained of 98.5% (w/w) filler, the rest consisted of dry binder and an antiadhesive agent. Our results showed that plasticity and elasticity may be considered independent deformation properties as highly plastic materials (microcrystalline cellulose, cornstarch) also exhibited high elasticity. Particular emphasis was placed on explaining the differences observed between the in-die and out-die method-comparison revealed that the differences are a consequence of the material's elastic properties. Larger error of in-die results can be expected for more elastic materials, and thus in-die Heckel should be used with some considerations. In contrast, the Walker model was found to be more robust and smaller differences were observed between the two methods. We consider the most correct results to have been obtained by the out-die approach, which excludes the elastic properties of the material evaluated. An excellent correlation between elastic determination at the single-particle level and multiple-particle scale was demonstrated, suggesting a great potential of nanoscale determination of a material's mechanical properties for better elucidation of deformation mechanisms.

Ili? I; Govedarica B; Šibanc R; Dreu R; Sr?i? S

2013-03-01

139

Deformation properties of pharmaceutical excipients determined using an in-die and out-die method.  

Science.gov (United States)

This study investigated deformation mechanisms of some commonly used pharmaceutical fillers, such as microcrystalline cellulose, lactose, dicalcium phosphate, isomalt and cornstarch, using a combination of the in-die and out-die method with the Heckel and Walker models. The tableting mixtures contained of 98.5% (w/w) filler, the rest consisted of dry binder and an antiadhesive agent. Our results showed that plasticity and elasticity may be considered independent deformation properties as highly plastic materials (microcrystalline cellulose, cornstarch) also exhibited high elasticity. Particular emphasis was placed on explaining the differences observed between the in-die and out-die method-comparison revealed that the differences are a consequence of the material's elastic properties. Larger error of in-die results can be expected for more elastic materials, and thus in-die Heckel should be used with some considerations. In contrast, the Walker model was found to be more robust and smaller differences were observed between the two methods. We consider the most correct results to have been obtained by the out-die approach, which excludes the elastic properties of the material evaluated. An excellent correlation between elastic determination at the single-particle level and multiple-particle scale was demonstrated, suggesting a great potential of nanoscale determination of a material's mechanical properties for better elucidation of deformation mechanisms. PMID:23402976

Ili?, Ilija; Govedarica, Biljana; Šibanc, Rok; Dreu, Rok; Sr?i?, Stane

2013-02-10

140

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

Directory of Open Access Journals (Sweden)

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.

O. Balkan; H. Demirer; E. Sabri Kayal?

2011-01-01

 
 
 
 
141

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

Science.gov (United States)

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.

Wang, Man; Zhou, Zhangjian; Sun, Hongying; Hu, Helong; Li, Shaofu

2012-11-01

142

Properties of the predicted super-deformed band in ^{32}S  

CERN Multimedia

Properties like the excitation energy with respect to the ground state, moments of inertia, B(E2) transition probabilities and stability against quadrupole fluctuations at low spin of the predicted superdeformed band of ^{32}S are studied with the Gogny force D1S using the angular momentum projected generator coordinate method for the axially symmetric quadrupole moment. The Self Consistent Cranking method is also used to describe the superdeformed rotational band. In addition, properties of some collective normal deformed states are discussed.

Rodríguez-Guzman, R R; Robledo, L M

2000-01-01

143

Experiment and analysis on elastic deformation properties of graphite and carbon materials for HTTR core components  

Energy Technology Data Exchange (ETDEWEB)

Fine-grained isotropic graphite grade IG-110, medium-grained near-isotropic graphite grade PGX and coarse-grained baked carbon grade ASR-ORB are employed as structural materials for the High Temperature Engineering Test Reactor (HTTR). The material properties for design are specified in Structural Design Code for Graphite Components of HTTR. This report describes in detail the experiment on deformation behavior including stress-strain relationship, elastic modulas and Poisson's ratio of each grade. An analytical method for linear elastic approximation leads to the property values contained in the Code. (author).

Arai, Taketoshi; Minato, Kazuo; Eto, Motokuni (Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment); Oku, Tatsuo; Yoda, Shinichi.

1992-06-01

144

Magnetic properties of maraging steel in relation to deformation and structural phase transformations  

Energy Technology Data Exchange (ETDEWEB)

Magnetic properties in annealed and cold rolled conditions have been investigated for maraging steel grade 18%Ni-2,400. The austenite content, coercive field, saturation magnetization and remanence were determined after aging for 1 h in the temperature range from 400 to 800 C. The results show that the degree of deformation imparted to martensite influences both the amount of reverted austenite and the magnetic properties obtained following aging. Transmission electron microscopy was carried out in order to investigate the structural changes taking place during reversion of austenite.

Ahmed, M.; Ali, A.; Hashmi, F.; Khan, A.Q. (Dr. A.Q. Khan, Research Labs., Rawalpindi (Pakistan)); Hasnain, S.K. (Quaid-e-Azam Univ., Islamabad (Pakistan). Dept. of Physics)

1994-03-01

145

Solvation of Glucose, Trehalose, and Sucrose by the Soft Sticky Dipole-Quadrupole-Octupole Water Model.  

UK PubMed Central (United Kingdom)

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.

Te JA; Tan ML; Ichiye T

2010-05-01

146

Characterization of (R,p,q)-deformed Rogers–Szegö polynomials: associated quantum algebras, deformed Hermite polynomials and relevant properties  

International Nuclear Information System (INIS)

This paper addresses a new characterization of (R,p,q)-deformed Rogers–Szegö polynomials by providing their three-term recurrence relation and the associated quantum algebra built with corresponding creation and annihilation operators. The whole construction is performed in a unified way, generalizing all known relevant results which are straightforwardly derived as particular cases. Continuous (R,p,q)-deformed Hermite polynomials and their recurrence relation are also deduced. Novel relations are provided and discussed. (paper)

2012-06-08

147

Characterization of ({ R},p,q)-deformed Rogers-Szegö polynomials: associated quantum algebras, deformed Hermite polynomials and relevant properties  

Science.gov (United States)

This paper addresses a new characterization of ({ R},p,q)-deformed Rogers-Szegö polynomials by providing their three-term recurrence relation and the associated quantum algebra built with corresponding creation and annihilation operators. The whole construction is performed in a unified way, generalizing all known relevant results which are straightforwardly derived as particular cases. Continuous ({ R},p,q)-deformed Hermite polynomials and their recurrence relation are also deduced. Novel relations are provided and discussed.

Bukweli Kyemba, J. D.; Hounkonnou, M. N.

2012-06-01

148

Deformation properties of osmium, platinum, mercury isotopes from self-consistent calculations: influence of the pairing treatment  

International Nuclear Information System (INIS)

[en] The deformation properties of several isotopes of the elements Os, Pt and Hg have been computed by means of Hartree-Fock plus BCS calculations. The Hartree-Fock potential has been derived from the Skyrme interaction S III. Two approximations have been used for the treatment of pairing correlations: the constant (versus deformation) gap method and the constant (versus deformation) pairing matrix element method. A good agreement with experimental data is obtained for ground state deformation properties except for the exact location of the prolate-oblate transition as a function of the neutron number. For one nucleus 184Hg, the pairing matrix elements have been calculated from the Gogny interaction D1, in order to study their single particle state- and deformation-dependence. From these results, the validity of the two approximations used for pairing correlations, is discussed

1981-01-01

149

Plastic deformation of amorphous poly(L/DL-lactide): structure evolution and physical properties.  

UK PubMed Central (United Kingdom)

Plastic deformation of amorphous, thermally noncrystallizable poly(L/DL-lactide) 70/30 (P(L/DL)LA) was induced by a plane-strain compression in a channel-die at different temperatures, above the glass transition (Tg) from 60 to 90 degrees C. Samples undeformed (reference) and deformed to different compression ratios, from 4.6 to 23.0, were studied by X-ray diffraction, thermally modulated differential scanning calorimetry, light microscopy, and mechanical methods-viscoelastic and tensile tests. The effects of the compression ratios and deformation temperatures on the final structure and properties of the P(L/DL)LA were evaluated. It was revealed that plastic deformation transformed an amorphous P(L/DL)LA (thermally noncrystallizable) to a crystalline fibrillar texture oriented in the flow direction. Fibrillar texture was formed in spite of the tendency of the plane-strain compression to form single-crystal-like texture. The crystallite size in the transverse direction was small, up to 90 angstroms at the highest compression ratio. No evidence of lamellar organization and features of supermolecular structure were detected by small-angle X-ray scattering and light microscopy, respectively. The oriented samples exhibited a low crystallinity degree at the level of 6-9% at the highest compression ratio. The main transformation mechanism was shear and orientation-induced crystallization. The crystalline phase was in the alpha crystallographic modification of poly(lactide) typically formed in more stereoregular poly(lactide) by thermal treatment. The glass transition increased with the increase of compression ratio reflecting the increase of orientation of the polymer chains. The tensile strength of deformed samples was improved considerably in comparison to that of the reference sample.

Pluta M; Galeski A

2007-06-01

150

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

1975-01-01

151

Surface deformation and electrical properties of HfN thin films deposited by reactive sputtering  

Energy Technology Data Exchange (ETDEWEB)

The electrical and mechanical properties of HfN films deposited on silicon by a reactive r.f. sputtering method are examined and discussed in terms of the films` structure and deposition conditions. The structural information has been obtained by employing a thin film X-ray diffraction method, Auger electron spectroscopy and electron microscopy. The recently developed energy principle of indentation has been applied in discussing the results of thin films` indentation by means of a depth-sensing technique. The theory allows the assessment of the details of surface deformation of nitrides, including the delamination process. The electrical properties of the studied films (i.e. resistivity and Hall coefficient) and their structure are found to be related to the deposition conditions. Moreover, the variation of the resistivity (electrical properties) appears to be accompanied by differences in the residual stress level as measured by the deflection method, and by differences in the mechanism of surface deformation (mechanical properties) of the HfN films. (orig.)

Nowak, R. [Nagoya Inst. of Tech. (Japan). Dept. of Electrical and Computer Engineering; Maruno, S. [Nagoya Inst. of Tech. (Japan). Dept. of Electrical and Computer Engineering

1995-11-01

152

Optimisation by plastic deformation of structural and mechanical uranium alloys properties  

International Nuclear Information System (INIS)

[en] Structural and mechanical properties evolution of rich and poor uranium alloys are investigated. Good usual properties are obtained with few metallic additions with a limited effect giving a fine and isotrope grain structure. Amelioration is observed with heat treatment from ? and ? phases high temperature range. However, dynamic recrystallisation, related to hot working, is the better phenomena to maximize the usual mechanical and structural properties. So high temperature behaviour of rich and poor uranium alloys in ?, ? and ? crystalline structure is studied: - dynamic recrystallisation phenomena begins only in ?, and ? phases high temperature range; - high strength and brittle ? phase shows a very large ductility above 700 deg C. Recrystallisation is a thermal actived phenomena localised at grain boundary, dependant with alloys concentration and crystalline structure. ? phase activation energy and deformation rate for dynamic recrystallisation beginning are most important, than ? and ? phases in relation with quadratic structure complexity. Both temperature and deformation rate are the main dynamic recrystallisation factors. Optimal usual mechanical and structural properties obtained by hot working (forging, milling) are sensible to hydrogen embrittlement

1981-01-01

153

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

DEFF Research Database (Denmark)

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.

KrogsbØll, Anette; Hededal, Ole

2012-01-01

154

Influence of stress on creep deformation properties of 9-12Cr ferritic creep resistant steels  

Energy Technology Data Exchange (ETDEWEB)

Creep deformation property of 9-12Cr ferritic creep resistant steels was investigated. With decrease in stress, a magnitude of creep strain at the onset of accelerating creep stage decreased from about 2% in the short-term to less than 1% in the longterm. A time to 1% total strain was observed in the transient creep stage in the short term regime, however, it shifted to the accelerating creep stage in the long-term regime. Life fraction of the times to 1% creep strain and 1% total strain tended to increase with decrease in stress. Difference in stress dependence of the minimum creep rate was observed in the high- and low-stress regimes with a boundary condition of 50% of 0.2% offset yield stress. Stress dependence of the minimum creep rate in the high stress regime was equivalent to a strain rate dependence of the flow stress evaluated by tensile test, and a magnitude of stress exponent, n, in the high stress regime decreased with increase in temperature from 20 at 550 C to 10 at 700 C. On the other hand, n value in the low stress regime was about 5, and creep deformation in the low stress regime was considered to be controlled by dislocation climb. Creep rupture life was accurately predicted by a region splitting method by considering a change in stress dependence of creep deformation. (orig.)

Kimura, K.; Sawada, K.; Kushima, H. [National Institute for Materials Science (Japan)

2008-07-01

155

Processing of metals by severe plastic deformation (SPD) – structure and mechanical properties respond  

Directory of Open Access Journals (Sweden)

Full Text Available SPD methods are used to convert coarse grain metals and alloys into ultrafine grained (UFG) materials. Obtained UFG materials then possess improved mechanical and physical properties which destine them for a wide commercial use. This paper, in one direction, looks into historical development of SPD processes and their effect at obtaining fine crystalline structure, and on the other side also partially focuses on development of UFG structure and its stability in commercial pure aluminium as a function of strain and post-deformation annealing applied.

J. Zrnik; S. V. Dobatkin; I. Mamuzi?

2008-01-01

156

Simultaneous Estimation of Material Properties and Pose for Deformable Objects from Depth and Color Images  

DEFF Research Database (Denmark)

In this paper we consider the problem of estimating 6D pose and material properties of a deformable object grasped by a robot grip- per. To estimate the parameters we minimize an error function incorpo- rating visual and physical correctness. Through simulated and real-world experiments we demonstrate that we are able to ?nd realistic 6D poses and elasticity parameters like Young’s modulus. This makes it possible to perform subsequent manipulation tasks, where accurate modelling of the elastic behaviour is important.

Fugl, Andreas Rune; Jordt, Andreas

157

Effects of crystallization on the mechanical properties of elastomers under large deformations  

Energy Technology Data Exchange (ETDEWEB)

Crystallization may occur in elastomers either at low temperatures or in the presence of large deformations. Even a small amount of crystallization by volume may have profound effects on mechanical properties of filled and unfilled elastomers. This paper will discuss observed behaviour in elastomers in relation to changes in elastic modulus, stress softening behaviour and crack propagation that may be attributed to crystallization at different temperatures. There will be some discussion of the underlying physical mechanisms thought to occur. The high molecular mobility in elastomers can also mean that their behaviour may provide a useful model for some aspects of the behaviour of other polymers, such as thermoplastics at elevated temperatures.

Stevenson, A. [Materials Engineering Research Lab. Ltd., Hertford (United Kingdom)

1995-12-31

158

Persistence of octupole correlations in {sup 231}Ra  

Energy Technology Data Exchange (ETDEWEB)

The structure of {sup 231}Ra, the heaviest odd Ra nucleus currently accessible for detailed spectroscopic investigation, has been studied in the {beta}{sup -} decay of {sup 231}Fr. The main purpose has been to verify whether fast B(E1) rates and significant octupole correlations recently established in {sup 229}Ra persist in {sup 231}Ra. The excited states in {sup 231}Ra have been determined for the first time. Spins and parities have been deduced from conversion electron measurements, while level half-lives in the ps and ns ranges have been measured with the Advanced Time Delayed {beta}{gamma}{gamma}(t) method. The moderately fast B(E1) rates found for transitions connecting the lowest-lying K{sup {pi}}=5/2{sup {+-}} and K{sup {pi}}=1/2{sup {+-}} bands, reveal the persistence of octupole collective effects in {sup 231}Ra, although the B(E1) rates are lower than in {sup 229}Ra. These findings reinforce the differences in the B(E1) systematics between isotonic Ra and Th nuclei.

Fraile, L.M. E-mail: fraile@iem.cfmac.csic.es; Borge, M.J.G.; Mach, H.; Boutami, R.; Aas, A.J.; Fogelberg, B.; Garcia-Raffi, L.M.; Grant, I.S.; Gulda, K.; Hageboe, E.; Kurcewicz, W.; Kvasil, J.; Lopez, M.J.; Loevhoeiden, G.; Martinez, T.; Rubio, B.; Tain, J.L.; Tengblad, O

2001-04-09

159

Octupole correlations in neutron-rich 143,145Ba and a type of superdeformed band in 145Ba  

International Nuclear Information System (INIS)

High spin states in neutron-rich odd-Z 143,145Ba nuclei have been investigated from the study of prompt ? rays in the spontaneous fission of 252Cf by using ?-?- and ?-?-?- coincidence techniques. Alternating parity bands are identified for the first time in 145Ba and extended in 143Ba. A new side band, with equal, constant dynamic, and kinetic moments of inertia equal to the rigid body value, as found in superdeformed bands, is discovered in 145Ba. Enhanced E1 transitions between the negative- and positive-parity bands in these nuclei give evidence for strong octupole deformation in 143Ba and in 145Ba. These collective bands show competition and coexistence between symmetric and asymmetric shapes in 145Ba. Evidence is found for crossing M1 and E1 transitions between the s=+i and s=-i doublets in 143Ba. copyright 1999 The American Physical Society

1999-01-01

160

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

International Nuclear Information System (INIS)

[en] 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

2006-01-01

 
 
 
 
161

Influence of Compatibilizer and Processing Conditions on Morphology, Mechanical Properties, and Deformation Mechanism of PP/Clay Nano composite  

International Nuclear Information System (INIS)

Polypropylene/montmorillonite nano composite was prepared by melt intercalation method using a twin-screw extruder with starve feeding system in this paper. The effects of compatibilizer, extruder rotor speed and feeding rate on properties of nano composite were investigated. Structure, tensile, and impact properties and deformation mechanism of the compounds were studied. For investigation of structure and deformation mechanisms, X-ray diffraction (XRD) and transmission optical microscopy (TOM) techniques were utilized, respectively. The results illustrate that introduction of the compatibilizer and also variation of the processing conditions affect structure and mechanical properties of nano composite.

2012-01-01

162

Influence of grain shape and orientation on the mechanical properties of high pressure torsion deformed nickel.  

UK PubMed Central (United Kingdom)

Severely plastically deformed (SPD) materials, for example those produced by high pressure torsion (HPT), are reported to possess outstanding mechanical properties. A typical HPT microstructure consists of elongated grains, usually of grain size well below 1 ?m, which are aligned parallel to the shear plane and showing typical shear texture components. To answer the question of how these single features of a SPD microstructure affect the mechanical properties individually, such as the yield strength, the ultimate tensile strength, the uniform elongation and the reduction in area, uniaxial tensile tests have been conducted. The samples were tested in two different orientations. Within the same testing orientation the average grain aspect ratio was also varied. The variation in grain aspect ratio within a sample was achieved through a slight back rotation of the already deformed material and selective radius-dependent specimen extraction. The main results are as follows: the ductility (in terms of the reduction in area) is influenced by the grain aspect ratio. In contrast, the ultimate tensile strength is independent of the grain aspect ratio but shows an explicit dependency on the specimen orientation.

Rathmayr GB; Hohenwarter A; Pippan R

2013-01-01

163

Developing superplastic properties in an aluminum alloy through severe plastic deformation  

Energy Technology Data Exchange (ETDEWEB)

Equal-channel angular (ECA) pressing is a processing procedure which subjects a material to severe plastic deformation. Tests were conducted on a commercial cast aluminum alloy to evaluate the properties associated with samples subjected to three different ECA pressing procedures. The results show that all three procedures lead to an ultrafine microstructure and each procedure is capable of producing samples which exhibit high strain rate superplasticity. Optimum superplastic properties were achieved in samples subjected to ECA pressing to a strain of {proportional_to}12. Under these conditions, the measured elongations to failure at a temperature of 673 K were 1210 and 950% at strain rates of 10{sup -1} and 1 s{sup -1}, respectively. (orig.)

Lee, S.; Berbon, P.B. [University of Southern California, Los Angeles, CA (United States). Dept. of Materials Science; Furukawa, M. [Department of Technology, Fukuoka University of Education, Munakata, Fukuoka (Japan); Horita, Z.; Nemoto, M. [Department of Materials Science and Engineering, Kyushu University, Fukuoka (Japan); Tsenev, N.K. [Institute of Chemical Technology, Ufa State Petroleum Technical University, Ufa (Russian Federation); Valiev, R.Z. [Institute of Physics of Advanced Materials, Ufa State Aviation Technical University, Ufa (Russian Federation); Langdon, T.G. [Departments of Materials Science and Mechanical Engineering University of Southern California, Los Angeles (United States)

1999-11-15

164

Perturbation analysis of the octupole-induced resonances in a storage ring  

Energy Technology Data Exchange (ETDEWEB)

This note is a continuation from LS-126, in which the authors derived a formula for the lowest-order amplitude-dependent tune shift for octupole-induced resonances. Here, the authors apply the canonical perturbation theory to the octupolar Hamiltonian and attempt to extend the analysis further in order to obtain much clearer insight on the octupole-induced resonances. The authors derive the distortion functions, which measure the distortions of the particle oscillation phase and amplitude in phase space. Based upon these distortion functions, they derive the higher-order amplitude-dependent tune shifts for octupoles.

Yoon, M.

1988-10-01

165

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 position-dependent 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.

Xi Yang*; Hong Yan

2011-01-01

166

Mechanical properties of sand tiger shark Carcharias taurus vertebrae in relation to spinal deformity.  

UK PubMed Central (United Kingdom)

Approximately 35% of sand tiger sharks Carcharias taurus in public aquaria exhibit spinal deformities ranging from compressed vertebrae and loss of intervertebral space to dislocated spines with vertebral degeneration and massive spondylosis caused by excessive mineralization both within vertebrae and outside the notochordal sheath. To identify the mechanical basis of these deformities, vertebral centra from affected (n = 12) and non-affected (n = 9) C. taurus were subjected to axial compression tests on an MTS 858 Bionix material testing system, after which mineral content was determined. Vertebral centra from affected sharks had significantly lower mineral content and material behavior in nearly all variables characterizing elasticity, plasticity, and failure. These mechanical deficiencies are correlated with size at capture, capture method, vitamin C and zinc deficiency, aquarium size, and swimming behavior in public aquaria. Non-affected C. taurus had greater stiffness and toughness even though these properties are generally incompatible in mineralized structures, suggesting that the biphasic (mineralized, unmineralized phases) nature of chondrichthyan vertebrae yields material behavior not otherwise observed in vertebrate skeletons. However, vertebral centra from non-affected sharks had lower mineral content (33%), stiffness (167 MPa), yield strain (14%), and ultimate strength (16 MPa) than other species of sharks and bony vertebrates, indicating that biomechanical precautions must be taken in the husbandry of this species.

Huber D; Neveu DE; Stinson CM; Anderson PA; Berzins IK

2013-08-01

167

The effect of plastic deformation and heat treatment on mechanical properties of tungsten heavy alloys  

International Nuclear Information System (INIS)

Tungsten heavy alloys (WHA) are particularly interesting family of two-phase, brittle-ductile metal composites. The W/Ni/Fe type of WHA usually contains between 90-97% of tungsten. As engineering material they exhibit attractive combination of high density, high strength and relatively high ductility. The mechanical properties of WHA can be Improved by plastic deformation and subsequent heat treatment. This paper presents results of room temperature tensile tests performed on the series of tungsten heavy alloy specimens representative of 'as sintered state' after cold working (10-40%) and additional annealing (500-750 oC). The results of microstructural microhardness and hardness measurements and fractography analysis are also given. (author)

2001-01-01

168

Nanostructure and properties of a Cu-Cr composite processed by severe plastic deformation.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A Cu-Cr composite was processed by severe plastic deformation to investigate the role of interphase boundaries on the grain size reduction mechanisms. The as-deformed material exhibits a grain size of only 20nm. This gives rise to a dramatic increase of the hardness. Some deformation induced Cu supe...

Sauvage, Xavier; Jessner, Peter; Vurpillot, François; Pippan, Reinhard

169

Reduced electric-octupole transition probabilities, B(E3;O1+ ? 31-), for even-even nuclides throughout the periodic table  

International Nuclear Information System (INIS)

Adopted values for the excitation energy, Ex(31-), of the first 3- state of the even-even nuclei are tabulated. Values of the reduced electric-octupole transition probability, B(E3;O1+ ? 31-), from the ground state to this state, as determined from Coulomb excitation, lifetime measurements, inelastic electron scattering, deformation parameters ?3 obtained from angular distributions of inelastically scattered nucleons and light ions, and other miscellaneous procedures are listed in separate Tables. Adopted values for B(E3; O1+ ? 31-) are presented in Table VII, together with the E3 transition strengths, in Weisskopf units, and the product Ex(31-) x B(E3; O1+ ? 31--) expressed as a percentage of the energy-weighted E3 sum-rule strength. An evaluation is made of the reliability of B(E3; O1+ ? 31-) values deduced from deformation parameters ?3. The literature has been covered to March 1988.

1988-01-01

170

THE EFFECTS OF HYDROGEN, TRITIUM, AND HEAT TREATMENT ON THE DEFORMATION AND FRACTURE TOUGHNESS PROPERTIES OF STAINLESS STEEL  

Energy Technology Data Exchange (ETDEWEB)

The deformation and fracture toughness properties of forged stainless steels pre-charged with tritium were compared to the deformation and fracture toughness properties of the same steels heat treated at 773 K or 873 K and precharged with hydrogen. Forged stainless steels pre-charged with tritium exhibit an aging effect: Fracture toughness values decrease with aging time after precharging because of the increase in concentration of helium from tritium decay. This study shows that forged stainless steels given a prior heat treatment and then pre-charged with hydrogen also exhibit an aging effect: Fracture toughness values decrease with increasing time at temperature. A microstructural analysis showed that the fracture toughness reduction in the heat-treated steels was due to patches of recrystallized grains that form within the forged matrix during the heat treatment. The combination of hydrogen and the patches of recrystallized grains resulted in more deformation twinning. Heavy deformation twinning on multiple slip planes was typical for the hydrogen-charged samples; whereas, in the non-charged samples, less twinning was observed and was generally limited to one slip plane. Similar effects occur in tritium pre-charged steels, but the deformation twinning is brought on by the hardening associated with decay helium bubbles in the microstructure.

Morgan, M.; Tosten, M.; Chapman, G.

2013-09-06

171

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

International Nuclear Information System (INIS)

[en] 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 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

1993-01-01

172

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

International Nuclear Information System (INIS)

[en] 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

1996-01-01

173

The influence of cold plastic deformation and heat treatment on the mechanical properties of stainless steels  

International Nuclear Information System (INIS)

The mechanical properties of the material depend to a high degree from its structure, namely from the heat treatment and plastic processing, as well as from the exploitation conditions. The chrome-nickel stainless steels are used as a construction material for the equipment, such as the heat exchanger and the steam generators, and the pipelines of the primary circuits of the pressure water reactors. Generally they are used after solution heat treatment. In this state the stainless steels have a relatively homogeneous austenitic structure with the presence of minute amounts of high-temperature ?-ferrite. In the course of manufacture of the equipment the components are subjected to the welding processes, plastic working and heat treatment. Also during exploitation the material is subjected to the influence of high temperatures, thermal shocks, mechanical loads and variable stresses. All these factors exert many changes in the structure of the stainless steels, mainly caused by the precipitation processes. In this paper the results of the investigation of the stainless steels with various carbon content after different kind of heat treatment and cold plastic deformation there are described. The influence of these factors on the mechanical properties of the steels was also studied. (author). 4 refs, 12 figs, 2 tabs

1992-01-01

174

Study of deformed nuclei properties using the Hartree-Fock method with the effective Skyrme-type interaction  

International Nuclear Information System (INIS)

By the Hartree-Fock method with the effective Skyrme forces the program system is described to calculate a wide range of static and dynamic properties of deformed nuclei. Some improvements are realized in the developed algorithms of Hartree-Fock equations allowing to save the time and to improve simultaneously the computation accuracy. On the base of these programs the theoretical analysis of binding energies of light deformed nuclei is carried out and good agreement with experiment is obtained. The spectra of 25Mg single-particle levels a are calculated and an essential rearrangement of a self-consistent field at high spin values is found

1985-01-01

175

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)

1998-01-01

176

Resulting strength and hardness properties after prior cyclic loading with superimposed incremental deformation of austenitic steel  

Energy Technology Data Exchange (ETDEWEB)

This paper covers the results obtained from experimental investigations into the stress/strain behaviour of niobium stabilised stainless steel piping material with the German notation X 6 CrNiNb 18 10, which is similar to AISI 347. From specimens tested in uniaxial experiments it could be proved that, independent of the size of the increment in strain and the cyclic strain range, a limited amount of applied, incremental, prior deformation reduced the overall capability to undergo deformation only by the amount of the accumulated, prior deformation. A clear relationship was observed between the level of prior deformation and the change in hardness. (authors)

Diem, H.K. [Stuttgart Univ. (Germany). MPA; Wachter, O. [PreussentElecktra AG, Hannover (Germany)

1998-07-01

177

Resulting strength and hardness properties after prior cyclic loading with superimposed incremental deformation of austenitic steel  

International Nuclear Information System (INIS)

This paper covers the results obtained from experimental investigations into the stress/strain behaviour of niobium stabilised stainless steel piping material with the German notation X 6 CrNiNb 18 10, which is similar to AISI 347. From specimens tested in uniaxial experiments it could be proved that, independent of the size of the increment in strain and the cyclic strain range, a limited amount of applied, incremental, prior deformation reduced the overall capability to undergo deformation only by the amount of the accumulated, prior deformation. A clear relationship was observed between the level of prior deformation and the change in hardness. (authors)

1998-01-01

178

Application of the multiphonon method to the study of the vibrational states with K = 0 in heavy deformed nuclei  

International Nuclear Information System (INIS)

The multiphonon method based on K/sup ?/ = 0- and K/sup ?/ = 0+ phonons is applied to heavy mass deformed even nuclei, such as Th, U, and Pu isotopes. Special emphasis is put on the location and properties of the ''two phonon'' states. Relative to an harmonic situation, the calculated energy spectra are systematically dilated. The octupole vibrations with K/sup ?/ = 0- present larger anharmonicities than the vibrations K/sup ?/ = 0+ which, in these nuclei, are found to be mainly of pairing nature. The two modes appear to be weakly coupled. The ''two phonon'' states are predicted to have an energy of about 1.7 to 2.0 MeV and keep some collective character through their electromagnetic transitions to the ''one phonon'' states. These conclusions are at variance with those of the quasiparticle phonon nuclear model of Soloviev et al.

1988-01-01

179

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

Directory of Open Access Journals (Sweden)

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.

Anibal Andrade Mendes Filho; Vitor Luiz Sordi; Maurizio Ferrante

2012-01-01

180

Processing of ultrafine-grained materials using severe plastic deformation: potential for achieving exceptional properties  

Directory of Open Access Journals (Sweden)

Full Text Available 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.El procesado de metales policristalinos a través de deformación plástica severa está atrayendo mucha atención, debido al potencial para alcanzar un importante afino de grano a niveles submicrométricos o nanométricos. Esta publicación revisa los principios de este tipo de procesado haciendo hincapié en dos técnicas diferentes: prensado en canal angular y torsión bajo alta presión. Mediante estos procesos, se pueden alcanzar propiedades excepcionales incluyendo alta resistencia a temperatura ambiente y una capacidad de conformación superplástica rápida a elevadas temperaturas. Se presentan algunos ejemplos demostrando el uso potencial de este tipo de procesado.

Langdon, T. G.

2008-01-01

 
 
 
 
181

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

Science.gov (United States)

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.

Mansoor, Bilal

182

Octupole correlations in neutron-rich 145,147La nuclei: Coriolis-limit-coupling bands with aligned h11/2 proton  

International Nuclear Information System (INIS)

Several new high-spin states are observed in the prompt ?-rays emitted from the neutron-rich, odd-Z 145,147La fragments produced in the spontaneous fission of 252Cf. Alternating parity bands are extended up to spins 41/2 and 43/2 in 145,147La, respectively. A new band completes the evidence for two sets of parity doublets expected for octupole correlations. Eight B(E1)/B(E2) ratios (four new) between two bands in 145La are all essentially constant and somewhat larger than similar ratios in 143,144Ba, where stable octupole deformation and/or correlations are reported. The new ratios out of the 31/2- levels in both nuclei show a sharp spike compared to other states, presumably from a strong reduction in E2 strengths in this backbending region. In 145La, collective bands show competition and coexistence between symmetric and asymmetric shapes. Band crossings occur in both nuclei around ???0.26 - 0.30 MeV. Their backbends are associated with the alignment of two i13/2 neutrons according to cranked shell model calculations. copyright 1999 The American Physical Society

1999-01-01

183

Screening and finite size corrections to the octupole and Schiff moments  

CERN Multimedia

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.

Flambaum, V V

2012-01-01

184

Search for octupole correlations in neutron-rich 148Ce nucleus  

International Nuclear Information System (INIS)

New transitions and levels in 148Ce have been observed in a ?-?-? coincidence study from the spontaneous fission of 252Cf with Gammasphere detector array. The ground band has been extended up to I?=22+, and side bands are extended with ?I=2 stretched transitions and ?I=1 crossing transitions. The observed level scheme is interpreted in terms of possible octupole correlations. Two sets of interwined positive- and negative- parity bands with the simplex quantum numbers s=±1 are suggested. The results of B(E1)/B(E2) branching ratios indicate that the octupole correlations in 148Ce are strong.

1000-01-00

185

Screening and finite-size corrections to the octupole and Schiff moments  

Science.gov (United States)

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 Z2?2 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 and P,T-odd interactions in molecules which are measured in numerous experiments to test CP-violation theories.

Flambaum, V. V.; Kozlov, A.

2012-06-01

186

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

Energy Technology Data Exchange (ETDEWEB)

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 {approx_equal}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 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)

Tyumentsev, A.; Pinzhin, Y.P.; Ditenberg, I.; Ovchinnikov, S.V.; Ermolaev, G.N.; Potapenko, M.M. [Institute of Strength Physics and Materials Science, Tomsk State University, SB, RAS, Tomsk (Russian Federation); Korotaev, A.D. [Tomsk State University, Tomsk (Russian Federation); Chernov, V.M. [Bochvar Institute of Inorganic Materials, P.O.Box 369, 123060 Moscow (Russian Federation)

2007-07-01

187

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 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)

2007-01-01

188

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.

1994-01-01

189

Deformed microstructure and mechanical properties of AM60B magnesium alloy under hypervelocity impact at a velocity of 4 km s-1  

International Nuclear Information System (INIS)

Deformed microstructure and mechanical properties of AM60B magnesium alloy under hypervelocity impact at a speed of 4 km s-1 were studied through optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM) and indenter technique. The results show that the deformed microstructure below the crater can be classified as three zones, i.e. dynamic recrystallization zone, high density deformation twin zone and low density deformation twin zone. The refined and equiaxed recrystallized grains adjacent to the crater were formed, which should be attributed to the twining-induced dynamic recrystallization mechanism. The {101-bar 2}, {101-bar 1} deformation twins are confirmed through selected area electron diffraction (SAED) technique. The microhardness and yield strength in the deformed microstructure zone near the crater are much higher than that of the matrix, which should be attributed to strain hardening and grain refining.

1500-01-00

190

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.

2011-09-15

191

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

192

Multiparticle octupole coupling and magnetic moments of hn9/2 isomers in N=126 isotones  

International Nuclear Information System (INIS)

[en] The influence of particle-vibration coupling on the g-factors of the (h9/2)n > isomers in the N = 126 isotones is assessed using the multiparticle octupole coupling model. According to the model, admixtures of the configuration (h9/2)n-1 f7/2> in the yrast 8+ and 21/2-states, nominally associated with the configuration (h9/2)n >, increase with n. On its own, the octupole mixing mechanism therefore predicts g-factors for these states that increase with the number of valence protons. This trend is the opposite of that predicted by core-polarization blocking. Combining multiparticle octupole coupling and first order core-polarization blocking significantly reduces the discrepancy between the experimental and theoretical g-factors of these states. It is concluded that the observed breakdown in additivity for the g-factors of the (h9/2)n > isomers in the N = 126 isotones arises primarily from first order core-polarization blocking and the combination of configuration mixing due to multiparticle octupole coupling and shell model residual interactions. 40 refs., 5 tabs., 3 figs

1992-01-01

193

Octupole coil configuration for the Tandem Mirror Experiment Upgrade (TMX-U)  

International Nuclear Information System (INIS)

The octupole plug concept offers the attractive possibility of reducing the length of the plug and transition sections in tandem mirror reactors. In the Tandem Mirror Experiment Upgrade (TMX-U), we are designing an octupole plug-transition that will replace our current quadrupole plug-transition. The reduction in length is made possible by the more nearly circular plasma cross section throughout the plug and transition sections. The principal physics of the design is the magnetohydrodynamic (MHD) stabilization of the core plasma in the plug by a hot electron ring in the mantle region surrounding the core. This hot electron mantle is MHD stable because of the good curvature field lines provided by the octupole. The positive radial pressure gradient in the hot electron mantle in turn stabilizes the core's plasma. Each octupole set consists of six coils replacing the transition and plug sets in the existing TMX-U experiment. The central cell coils will remain unchanged. Five of the coils for each of the new sets will be fabricated, while one, the 6-T mirror coil, will be reused from TMX-U. This paper will elaborate on the design configuration of the magnets. In particular, the configuration provides for adequate neutral beam lines-of-sight, and access for 0.615 MW of electron-cyclotron resonant heating (ECRH) on each end.

1985-01-01

194

Anharmonicity of the excited octupole band in actinides using supersymmetric quantum mechanics  

Science.gov (United States)

Background: Low-lying octupole collective excitations play an important role in the description of the structure of nuclei in the actinide region. Ground state alternating parity rotational bands combining both positive and negative parity states are known in several nuclei. However, only recently it has been discovered in 240Pu an excited positive parity rotational band having an octupole nature and demonstrating strong anharmonicity of the octupole motion in the band head energies.Purpose: To suggest a model describing both ground state and excited alternating parity bands, which includes a description of the anharmonic effects in the bandhead excitation energies and can be used to predict the energies of the excited rotational bands of octupole nature and the E1 transition probabilities.Methods: The mathematical technique of the supersymmetric quantum mechanics with a collective Hamiltonian depending only on the octupole collective variable which keeps axial symmetry is used to describe the ground state and excited alternating parity rotational bands.Results: The excitation energies of the states belonging to the lowest negative parity and the excited positive parity bands are calculated for 232Th, 238U, and 240Pu. The E1 transition matrix elements are also calculated for 240Pu.Conclusions: It is shown that the suggested model describes the excitation energies of the states of the lowest negative parity band with the accuracy around 10 keV. The anharmonicity in the bandhead energy of the excited positive parity band is described also. The bandhead energy of the excited positive parity band is described with the accuracy around 100 keV.

Jolos, R. V.; von Brentano, P.; Casten, R. F.

2013-09-01

195

The impact of cold deformation, annealing temperatures and chemical assays on the mechanical properties of platinum  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In order to form the necessary data base on platinum and platinum metals, certain tests were carried out on platinum samples of different purity of 99.5%, 99.9% and 99.99%. The degree of cold deformation, annealing temperature and chemical assays were tested as well as their impact on the mechanical...

Trumi? B.; Stankovi? D.; Ivanovi? A.

196

Effect of various mechanical deformation on the properties of silver-clad bi-2223 composites  

Energy Technology Data Exchange (ETDEWEB)

While the wire processing method was found to produce no noticeable difference in the silver/core interface, the tape forming technique resulted in significantly different interface. Pressing produced more wavy silver/core interface (sausaging) than flat-rolling and transverse rolling. Cracks were also found common in pressed samples, but rare in flat-rolled and transverse-rolled samples. Furthermore, the direction of sausaging was found to be dependent on the mechanical deformation technique used, i.e., along the length of tape in pressed and transverse-rolled samples and along the width of tape in flat-rolled tapes. The green tapes were heat treated using a thermomechanical process consisting of alternate mechanical deformation and sintering. For comparison, a control tape in which no deformation was used between sinterings was also prepared using the same sintering conditions. After each step of heat treatment, tapes were characterised in terms of high-T{sub c} phase fraction, microstructure and critical current density (J{sub c}). The results indicated that the mechanical deformation accelerated the Bi-2223 phase formation rate, in particular, the pressed samples showed the fastest Bi-2223 phase formation rate. For the J{sub c}, pressing yielded the highest value, probably due to the high density and excellent grain alignment in the pressed tapes

Guo, Y.C.; Akmacic, D; Wang, H.; Liu, H. K.; Dou, S. X. [The University of Wollongong, Wollongong, NSW (Australia). Centre for Superconducting and Electronic Materials

1996-12-31

197

An Investigation of the Mechanical Properties of 30KhGSA Steel in Plastic Deformation.  

Science.gov (United States)

Specimens of 30KhGSA steel were subjected to tensile test after standard heat treatment, and also after large plastic deformation followed by stress relieving at 200, 300, 350, or 625C for 2-30 min. The tensile and yield strength of unstrained specimens (...

N. A. Bukin

1969-01-01

198

Study on the testing method and procedures for engineering properties of NPP site : compressive strength and rock mass deformation modulus  

Energy Technology Data Exchange (ETDEWEB)

This study have been carried out for attempting to develop the minimum requirements of testing methods and procedures for determining engineering properties for foundation bedrock at NPP site. As a first phase study, for the compressive strength and deformation modulus of rock important to the safety evaluation of the bearing capacity and settlement of the foundation, the testing methods and procedures for determining the two characteristic values were reviewed and comparison between each value of the sites under studying was carried out. The data originated from Wolsong 1 spent fuel dry storage site and the NPP sites of Yonggwang 3 {center_dot} 4, Wolsong 2{center_dot}3{center_dot}4, and Ulchin 3{center_dot}4. Also, re-evaluation was made for the data excluded from original analysis, and especially re-calculation of rock mass deformation modulus of Wolsong unit 2 was conducted by using the settlement data. The analysis result show that the uniaxial compressive and point load tests had been conducted for compressive strength and the jack test, hydraulic pressure meter test, and correlation methods using RQD, RMR, and velocity index were conducted for rock mass deformation modulus. It is also found that there was a tendency to decide characteristic values by selecting the lower value among various test results rather than considering the credibility of the test results.

Shim, T. M.; Lee, S. K.; Noh, M. H.; Lee, H. W. [KINS, Taejon (Korea, Republic of)

2001-05-01

199

Deformation-induced grain boundary wetting and its effects on the acoustic and rheological properties of partially molten rock analogue  

Science.gov (United States)

An experimental study was performed to investigate the effects of deviatoric stress on the microstructure of partially molten polycrystalline aggregates. Borneol (organic crystal) + melt system having an eutectic temperature of 43°C and a moderate dihedral angle was used as a partially molten rock analogue. Large samples (70 mm cube) having melt fractions of 0.089-0.22 were deformed ductilely under a uniform pure shear stress (shear strain rate of ˜0.8-7×10-7 s-1), while monitoring the sample microstructure in situ using ultrasonic shear waves. Each sample was deformed repeatedly by changing the principal stress direction, resulting in the microstructural changes well detectable under the microscope. The most remarkable features of the stress- and/or deformation-induced microstructural changes are enhanced grain boundary wetting, enhanced grain coarsening, and formation of large (approximately sample scale) melt sheet parallel to the shear plane, which is an assembly of completely wetted two-grain boundaries at the microscopic scale. Significant changes in the elastic, anelastic, and viscous properties associated with these microstructural changes were observed. The velocity monitoring provided a detailed picture of growth and healing of grain boundary melt films in response to loading cycles. The microstructural changes observed in this study have many similarities with the "dynamic wetting" reported for the partially molten peridotite.

Takei, Yasuko

2005-12-01

200

The effect of deformation and heat treatment on the structure and properties of hardened and aged alloy 36NTYu  

International Nuclear Information System (INIS)

[en] A study is made into variations of structure and mechanical properties of alloy 36NTYu after various treatments: quench ageing at 750 deg C, deformation with reduction of ? = 50-98%, annealing at 750 deg C. Mechanical tests on tension and fatigue as well as electron microscopical analysis are performed. Changes in dislocation structure and ?'-phase precipitates in the form of lamellae during the treatment are investigated. It is shown that there is a fair correlation between endurance limit and friction stress[ru] ??????????? ????????? ????????? ? ???????????? ??????? ?????? 36??? ????? ????????? ?????????: ??????? ?? ????????? ??? 750 ???? ?, ?????????? ?? ????????? ? = 50-98%, ?????? ??? 750 ???? ?. ????????? ???????????? ????????? ?? ?????????? ? ?????????, ? ????? ??????????-???????????????? ??????. ??????????? ????????? ?????????????? ????????? ? ????????? ?'-???? ? ???? ??????? ? ???????? ?????????. ????????, ??? ????? ???????? ???????????? ? ??????????? ?????? ??????? ??????? ??????????

2002-01-01

 
 
 
 
201

Tailoring the Mechanical Properties of a Twinning-Induced Plasticity Steel by Retention of Deformation Twins During Heat Treatment  

Science.gov (United States)

The relation between microstructure and mechanical properties of a 30 pct cold-rolled, recovery-annealed, and recrystallization-annealed Fe-23Mn-1.5Al-0.3C twinning-induced plasticity (TWIP) steel was studied. The thermal stability of deformation-induced twin boundaries along with a reduced dislocation density due to annihilation during recovery annealing at 903 K (630 °C) was found to be a simple, promising processing route to overcome the shortcoming of low yield strength usually associated with TWIP steels.

Haase, Christian; Barrales-Mora, Luis Antonio; Molodov, Dmitri A.; Gottstein, Günter

2013-10-01

202

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

Science.gov (United States)

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.

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

2013-05-01

203

Magnetic properties of deformed dipole bands in {sup 110,112}Te  

Energy Technology Data Exchange (ETDEWEB)

A lifetime analysis using the Doppler-shift attenuation method has been performed on the Tellurium isotopes {sup 110,112}Te. The experiment was performed using the Gammasphere array in conjunction with the MICROBALL charged-particle detector. Three strongly coupled bands were previously established in {sup 110,112}Te which were observed up to unusually high spins. In the current experiment, it has been possible to extract lifetime measurements using a Doppler broadened lineshape analysis on one of the {delta}I=1 band structures in {sup 110}Te. In contrast to similar {delta}I=1 structures in other nuclei in this mass region, the extracted B(M1) values did not rapidly decrease with increasing angular momentum. Instead, the strongly coupled band in {sup 110}Te represents a deformed 1p-1h structure, rather than a weakly deformed structure showing the shears mechanism.

Evans, A O; Paul, E S; Boston, A J; Chantler, H J [Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Chiara, C J [Department of Physics and Astronomy, University of New York, Stony Brook, NY (United States); Devlin, M [Department of Chemistry, Washington University, St Louis, MO 63130 (United States); Fletcher, A M [Schuster Laboratory, University of Manchester, Brunswick Street, Manchester (United Kingdom); Fossan, D B [Department of Physics and Astronomy, University of New York, Stony Brook, NY (United States); LaFosse, D R [Department of Chemistry, Washington University, St Louis, MO 63130 (United States); Lane, G J [Department of Physics and Astronomy, University of New York, Stony Brook, NY (United States); Lee, I Y [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Macchiavelli, A O [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Nolan, P J [Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Sarantites, D G [Department of Chemistry, Washington University, St Louis, MO 63130 (United States); Sears, J M [Department of Physics and Astronomy, University of New York, Stony Brook, NY (United States); Semple, A T [Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Smith, J F [Schuster Laboratory, University of Manchester, Brunswick Street, Manchester (United Kingdom); Starosta, K [Department of Physics and Astronomy, University of New York, Stony Brook, NY (United States); Vaman, C [Department of Physics and Astronomy, University of New York, Stony Brook, NY (United States); Ragnarsson, I [Department of Mathematical Physics, University of Lund, Lund (Sweden); Afanasjev, A V [Department of Mathematical Physics, University of Lund, Lund (Sweden)

2006-07-15

204

E4 properties in deformed nuclei and the sdg interacting boson model  

International Nuclear Information System (INIS)

The hexadecapole transition strength distribution is measured for the deformed nucleus /sup 150/Nd using the (p,p') reaction at E/sub p/ = 30 MeV. The experimental information on B(E4) values in this nucleus and in /sup 156/Gd is interpreted in the framework of the sdg interacting boson model. It is found that the main features of the experimental data are fairly well reproduced by a Hartree-Bose method plus Tamm-Dancoff approximation.

1988-01-01

205

Deformation and strength properties of three structural varieties of Carboniferous sandstone in conventional triaxial compression  

Energy Technology Data Exchange (ETDEWEB)

Three structural types of quartzitic Carboniferous sandstone from the Rybnik Coalfield were tested in conditions of conventional triaxial compression at confining pressures up to 60 MPa. The effects of confining pressure on a number of deformational and strength parameters were determined, as well as the conditions of transition from the brittle state to the ductile. The test results were analysed, taking account of the grain size of the sandstones, their porosity and mineral composition.

Kwasniewski, M.

1983-01-01

206

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

2001-01-01

207

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

CERN Document Server

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 discussed.

Fang, Dong-Liang; Suzuki, Toshio

2012-01-01

208

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).

1983-01-01

209

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

International Nuclear Information System (INIS)

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.)

2012-01-01

210

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)

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.)

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

2012-05-15

211

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

International Nuclear Information System (INIS)

[en] 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)

2011-01-01

212

Octupole excitations in vibrational nuclei and the sdf interacting boson model  

Energy Technology Data Exchange (ETDEWEB)

Proton and deuteron inelastic scattering experiments, performed with an energy resolution of 12-15 keV, have been used to study negative-parity states of vibrational and transitional nuclei with mass between 98 and 150. The analysis has been focussed on the isovector components, on the quadrupole-octupole two-phonon states and on the fragmentation of the octupole strength. This latter displays a regular dependence on the product of proton and neutron valence particle numbers and is satisfactorily reproduced by IBM-1+f-boson calculations. Other features of the experimental spectra, as the relative positions of the 3{sup -} states, exhibit a dependence on the ratio of valence particle numbers and indicate that a IBM-2 approach might be more appropriate. (orig.).

Pignanelli, M.; Blasi, N.; Micheletti, S. (Milan Univ. (Italy). Dipt. di Fisica Istituto Nazionale di Fisica Nucleare, Milan (Italy)); De Leo, R. (Lecce Univ. (Italy). Dipt. di Fisica Istituto Nazionale di Fisica Nucleare, Lecce (Italy)); Hofstee, M.A.; Schippers, J.M.; Werf, S.Y. van der (Rijksuniversiteit Groningen (Netherlands). Kernfysisch Versneller Inst.); Harakeh, M.N. (Vrije Univ., Amsterdam (Netherlands). Faculteit Natuurkunde en Sterrekunde)

1990-12-10

213

Octupole excitations in vibrational nuclei and the sdf interacting boson model  

Science.gov (United States)

Proton and deuteron inelastic scattering experiments, performed with an energy resolution of 12-15 keV, have been used to study negative-parity states of vibrational and transitional nuclei with mass between 98 and 150. The analysis has been focussed on the isovector components, on the quadrupole-octupole two-phonon states and on the fragmentation of the octupole strength. This latter displays a regular dependence on the product of proton and neutron valence particle numbers and is satisfactorily reproduced by IBM-1 + f-boson calculations. Other features of the experimental spectra, as the relative positions of the 3- states, exhibit a dependence on the ratio of valence particle numbers and indicate that a IBM-2 approach might be more appropriate.

Pignanelli, M.; Blasi, N.; Micheletti, S.; de Leo, R.; Hofstee, M. A.; Schippers, J. M.; van der Werf, S. Y.; Harakeh, M. N.

1990-12-01

214

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

International Nuclear Information System (INIS)

Octupole vibrational states were studied in the nucleus 150Nd via inelastic proton scattering with 10.9-MeV protons, which are an excellent probe to excite natural parity states. For the first time in 150Nd, both the scattered protons and the ? 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 calculations performed in the spdf boson space. The calculations are found to be in good agreement with the experimental data, for both positive and negative-parity states.

2011-01-01

215

Indication for a K/sup ?/ = 0- octupole band in 150Nd from electron scattering  

International Nuclear Information System (INIS)

[en] Recent electron scattering results on the 0.850 MeV level of 150Nd, when analyzed in terms of the interacting boson model, are inconsistent with the interpretation of this level as a pure J/sup ?/(K) = 2+(0) state. Very recent (n,n'?) work has shown this level to be a 1-, 2+ doublet. Assuming this level to be the band head of a ''K/sup ?/ = 0-'' octupole band, a simple model is used to predict electron scattering form factors for the 0.850 MeV state and a 3- octupole level observed at 0.931 MeV. Comparison is made between these predicted form factors and recent electron scattering data

1978-01-01

216

Coriolos mixing of the octupole-vibrational states in 156Gd  

International Nuclear Information System (INIS)

The Coriolis mixing of the negative parity states in the 156Gd in the framework of the phenomenological model is considered. The energy values and branching ratios of E1-transition proceeding from octupole bands states are described. The E1-transition possibilities proceeding from K?=2- band levels are discussed, as well as E2-transitions probabilities inside the K?=)-, 1- and 2- bands are calculated. 15 refs.; 3 figs.; 4 tabs.

1992-01-01

217

Microscopic investigation of octupole modes of oscillation via analyzing power measurements  

International Nuclear Information System (INIS)

[en] Measurements of the analyzing power in the two-nucleon transfer reactions 70Ge, 72Ge (t,p) have been carried out. This is a region where a shape transition has been previously proposed. Contrary to recent (p,t) results, no strong interference effects between direct and two step processes leading to the 21+ states have been observed. However, a marked difference has been revealed for the 31- octupole transition. A microscopic interpretation of this effect is proposed

1980-01-01

218

Investigation of mechanical properties and operative deformation mechanism in nano-crystalline Ni–Co/SiC electrodeposits  

International Nuclear Information System (INIS)

Highlights: ? The tensile properties of Ni–Co and Ni–Co/SiC deposits were investigated. ? The SiC particles enhanced tensile strength and ductility of nano-structured composites. ? The deformation mechanism at low and high strain rates were studied. - Abstract: Ni–Co/SiC nano-composites were prepared via electrodeposition from a modified Watts bath containing SiC particles with average particle size of 50 nm, SDS as surfactant and saccharin as grain refiner in appropriate amounts. The effect of nano-particle incorporation on microstructure, mechanical properties and deformation mechanism of electrodeposits were investigated. The mechanical properties of electrodeposits were investigated by Vickers microhardness and tensile tests. The results indicated that incorporation of SiC particles into a 15 nm Ni–Co matrix had no considerable effect on its microhardness and yield strength, that is, dispersion hardening did not operate in this range of grain size. However it was observed that co-deposition of uniform distributed SiC particles can significantly improve the ultimate tensile strength and elongation to failure of the deposits. Calculation of apparent activation volume from tensile test results at different strain rates proved that incorporation of SiC nano-particles are responsible for stress-assisted activation of GB atoms mechanism that can significantly increase the plasticity. Nano-crystalline Ni–Co matrix showed a mixed mod behavior of ductile and brittle fracture whereas incorporation of SiC particles and increasing the strain rate promoted ductile fracture mode.

2012-04-30

219

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

Directory of Open Access Journals (Sweden)

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.

M. Greger; V. Vodárek; L. Kander; L. ??žek

2009-01-01

220

Electrical and magnetic properties of hot-deformed Nd-Fe-B magnets with different DyF3 additions  

Science.gov (United States)

The effect of deformation and DyF3 additions on the electrical resistivity and the magnetic performance has been studied in hot-deformed Nd-Fe-B melt-spun ribbons and correlated with respective microstructures. Despite the nanocrystallinity of hot-compacted magnets, the specific electrical resistivity measured by four-point-method was shown to be comparable with that of sintered magnets. Die-upsetting reduces electrical resistivity within the magnetically hard plane because of an enhanced shape anisotropy of the grains. The addition of DyF3 overcompensates this reduction due to the presence of electrically insulating Dy-F rich inclusions and thus reduces eddy current losses within the magnet. Magnetic measurements reveal an increase in coercivity without a change in remanence for die-upset magnets with a total height reduction of 63% and 1.2 wt. % Dy (1.6 wt. %DyF3). Both properties, remanence and coercivity, demonstrate an effective reduction in heavy rare earth Dy for Nd-Fe-B magnets.

Sawatzki, Simon; Dirba, Imants; Schultz, Ludwig; Gutfleisch, Oliver

2013-10-01

 
 
 
 
221

Mechanical Properties of Nano- and Submicrocrystalline Iron Subjected to Severe Plastic Deformation by Friction  

Directory of Open Access Journals (Sweden)

Full Text Available By using nanoindentation technique relationship between microstructure and mechanical parameters such as nanohardness Hh, plasticity characteristic, and Young’s modulus E were found to be dependent on the grain size of the bcc-Fe subjected to severe plastic deformation by friction (SPDF) with argon atmosphere. Unlike fcc-metals in which the decreasing of grain size to 20 nm results in hardness growth accompanied by decreasing the plasticity, it was found the reverse effect in bcc-Fe, i.e. decreasing the grain size from 50 to 20 nm caused the decrease of hardness and increase of plasticity. Moreover, the decrease of Young’s modulus E with decreasing the grain size down to 20 nm was detected in nanoindentation experiments.

Yurkova A.I.; Byakova A.V.

2012-01-01

222

Role of deformation on giant resonances within the QRPA approach and the Gogny force  

CERN Multimedia

Fully consistent axially-symmetric-deformed Quasi-particle Random Phase Approximation (QRPA) calculations have been performed, in which the same Gogny D1S effective force has been used for both the Hartree-Fock-Bogolyubov mean field and the QRPA approaches. Giant resonances calculated in deformed $^{26-28}$Si and $^{22-24}$Mg nuclei as well as in the spherical $^{30}$Si and $^{28}$Mg isotopes are presented. Theoretical results for isovector-dipole and isoscalar monopole, quadrupole, and octupole responses are presented and the impact of the intrinsic nuclear deformation is discussed.

Peru, S

2008-01-01

223

The properties of collective states of even-even deformed nuclei of rare earth range 156  

International Nuclear Information System (INIS)

Aims of inquiry: development of phenomenological model, based on mixing of rotational bands, description of non-adiabatic properties of energy and electromagnetic characteristics of excited states of nuclei for isotopes 156-164Dy and 172Yb as example. Method of inquiry: phenomenological and microscopical model of deformed nuclei based on mixing rotational bands. The results achieved and their novelty: 1. phenomenological model that accounts for coriolis mixing of ground (gr), ?-, ?- and 1+ bands. 2. It is shown that the involvement of 1+components in wave functions of vibrational states causes M1 transitions. Experimentally observed K-forbidden monopole electric and dipole magnetic transitions from levels of K?=2n+-bands to those of ground bands are explained. 3. On the basic of microscopic analysis it is shown that in the 'scissors' mode region Coriolis coupling between the ground and 1+ states is equal to zero. This effect is most interesting and unexpected. (author)

2006-01-01

224

Rotational bands in deformed odd-A nuclei in the actinide region  

Energy Technology Data Exchange (ETDEWEB)

Tables of experimentally known energy levels of odd-A rotational bands in the actinide region (A {ge} 221) are presented along with the configuration assignments. This includes the newly defined quadrupole-octupole deformation region (A {le} 229). The moment of inertia and the decoupling parameters have been calculated for each band if sufficient data are available. Useful theoretical and experimental information for each band/nucleus is also given. The cutoff date for the present compilation is December 1990.

Jain, K.; Jain, A.K. (Univ. of Roorkee (India))

1992-03-01

225

Modeling of Developing Inhomogeneities in the Ferrite Microstructure and Resulting Mechanical Properties Induced by Deformation in the Two-Phase Region  

Energy Technology Data Exchange (ETDEWEB)

The differences in microstructure development of hot deformed steels in the austenite and two-phase region have been effectively described using an integrated computer modeling process. In general, the complete model presented here takes into account kinetics of recrystallization, precipitation, phase transformation, recrystallized austenite grain size, ferrite grain size, and the resulting mechanical properties. The transformation submodel of niobium-microalloyed steels is based on the nucleation and grain growth theory and additivity rule. The thermomechanical part of the modeling process was effectively carried out using the finite element method. Results were obtained in different temperatures, strain rates, and range of deformation. The thermomechanical treatments are different for two grades of niobium-steels to make possible analysis of the resulting structure and properties for different histories of deformation and chemical composition.

Majta, J; Zurek, A.K.; Pietrzyk, M.

1999-07-13

226

Creep Properties and Deformation Mechanisms of a FGH95 Ni-based Superalloy  

Science.gov (United States)

By means of full heat treatment, microstructure observation, lattice parameters determination, and the measurement of creep curves, an investigation has been conducted into the microstructure and creep mechanisms of FGH95 Ni-based superalloy. Results show that after the alloy is hot isostatically pressed, coarse ?' phase discontinuously distributes along the previous particle boundaries. After solution treatment at high temperature and aging, the grain size has no obvious change, and the amount of coarse ?' phase decreases, and a high volume fraction of fine ?' phase dispersedly precipitates in the ? matrix. Moreover, the granular carbides are found to be precipitated along grain boundaries, which can hinder the grain boundaries' sliding and enhance the creep resistance of the alloy. By x-ray diffraction analysis, it is indicated that the lattice misfit between the ? and ?' phases decreases in the alloy after full heat treatment. In the ranges of experimental temperatures and applied stresses, the creep activation energy of the alloy is measured to be 630.4 kJ/mol. During creep, the deformation mechanisms of the alloy are that dislocations slip in the ? matrix or shear into the ?' phase. Thereinto, the creep dislocations move over the ?' phase by the Orowan mechanism, and the < { 1 10 } rangle super-dislocation shearing into the ?' phase can be decomposed to form the configuration of (1/3) < { 1 12 } rangle super-Shockleys' partials and the stacking fault.

Xie, Jun; Tian, Su-gui; Zhou, Xiao-ming

2013-07-01

227

Fractal property of interfacial or surface inhomogeneous deformation. Kaimen aruiwa hyomen fukinshitsu henkei no furakutaru tokusei  

Energy Technology Data Exchange (ETDEWEB)

Fractal analysis by changing the conventional roughening profile was carried out for geometrical morphology of surface or interface of arbitrary cross section. As for each strain levels including nonnegative load, it has been revealed that there exists a scale representing fractal characteristics in inhomogeneous deformation. In the region, where macrostructural changes, except the optimum fracture of fractal dimension and nonnegative load condition, were observed, the fractal dimension of pure aluminium has increased slightly with the negative load strain where as the fractal dimension of aluminium alloy has been almost constant. According to the surface characteristics, the interfacial roughening has differed greatly from the surface roughening, however it has heen almost same in case of fractal dimension. Fractal has been analyzed by the pseudo-roughening condition caused by computer simulation. Simulation results and experimental results have shown good agreement in the case where number of fractal dimensions exist due to the elemental level superposition and change in the fractal level, and the study has been justified. 14 refs., 8 figs.

Shibutani, Y.; Kitagawa, H. (Osaka Univ., Suita (Japan). Faculty of Engineering); Nakamura, T. (Osaka Univ., Osaka (Japan). Graduate Student)

1992-11-15

228

Deformable Nanolaminate Optics  

Energy Technology Data Exchange (ETDEWEB)

We are developing a new class of deformable optic based on electrostatic actuation of nanolaminate foils. These foils are engineered at the atomic level to provide optimal opto-mechanical properties, including surface quality, strength and stiffness, for a wide range of deformable optics. We are combining these foils, developed at Lawrence Livermore National Laboratory (LLNL), with commercial metal processing techniques to produce prototype deformable optics with aperture sizes up to 10 cm and actuator spacing from 1 mm to 1 cm and with a range of surface deformation designed to be as much as 10 microns. The existing capability for producing nanolaminate foils at LLNL, coupled with the commercial metal processing techniques being used, enable the potential production of these deformable optics with aperture sizes of over 1 m, and much larger deformable optics could potentially be produced by tiling multiple deformable segments. In addition, based on the fabrication processes being used, deformable nanolaminate optics could potentially be produced with areal densities of less than 1 kg per square m for applications in which lightweight deformable optics are desirable, and deformable nanolaminate optics could potentially be fabricated with intrinsically curved surfaces, including aspheric shapes. We will describe the basic principles of these devices, and we will present details of the design, fabrication and characterization of the prototype deformable nanolaminate optics that have been developed to date. We will also discuss the possibilities for future work on scaling these devices to larger sizes and developing both devices with lower areal densities and devices with curved surfaces.

Olivier, S S; Papavasiliou, A P; Barbee, T W; Miles, R R; Walton, C C; Cohn, M B; Chang, K

2006-05-12

229

High-temperature mechanical properties and deformation behavior of high Nb containing TiAl alloys fabricated by spark plasma sintering  

Science.gov (United States)

A high Nb containing TiAl alloy was prepared from the pre-alloyed powder of Ti-45Al-8.5Nb-0.2B-0.2W-0.02Y (at%) by spark plasma sintering (SPS). Its high-temperature mechanical properties and compressive deformation behavior were investigated in a temperature range of 700 to 1050°C and a strain rate range of 0.002 to 0.2 s-1. The results show that the high-temperature mechanical properties of the high Nb containing TiAl alloy are sensitive to deformation temperature and strain rate, and the sensitivity to strain rate tends to rise with the deformation temperature increasing. The hot workability of the alloy is good at temperatures higher than 900°C, while fracture occurs at lower temperatures. The flow curves of the samples compressed at or above 900°C exhibit obvious flow softening after the peak stress. Under the deformation condition of 900-1050°C and 0.002-0.2 s-1, the interrelations of peak flow stress, strain rate, and deformation temperature follow the Arrhenius' equation modified by a hyperbolic sine function with a stress exponent of 5.99 and an apparent activation energy of 441.2 kJ·mol-1.

Lu, Xin; Zhao, Li-hua; Zhu, Lang-ping; Zhang, Bin; Qu, Xuan-hui

2012-04-01

230

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

Directory of Open Access Journals (Sweden)

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.

V. I. Semenov; S.-J. Huang; L. Sh. Shuster; P.-C. Lin

2011-01-01

231

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)

2012-01-01

232

A novel antiproton radial diagnostic based on octupole induced ballistic loss  

CERN Multimedia

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.

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

233

High-energy component of giant octupole resonance in medium and heavy mass nuclei  

Energy Technology Data Exchange (ETDEWEB)

Inelastic scattering of /sup 3/He particles at 110--140 MeV from /sup 90,92/Zr, /sup 116,118,120/Sn, /sup 144/Sm, and /sup 208/Pb nuclei exhibits the presence of a new giant resonance at E/sub x/approx.118A/sup -1/3/ MeV with a width of about 7 MeV. The angular distributions are consistent with those for L=3 transfer and octupole energy-weighted sum-rule fractions of 47--95% are exhausted for the resonance.

Yamagata, T.; Kishimoto, S.; Yuasa, K.; Iwamoto, K.; Saeki, B.; Tanaka, M.; Fukuda, T.; Miura, I.; Inoue, M.; Ogata, H.

1981-02-01

234

Progress Towards A Permanent Octupole Magnetic Ultra-Cold Neutron Trap for Lifetime Measurements  

CERN Document Server

The current knowledge of the neutron $\\beta$-decay lifetime has come under scrutiny as of late due to large disagreements between recent precise measurements. Measurements using magnetically trapped Ultra-Cold Neutrons (UCNs) offer the possibility of storage without spurious losses which can provide a reliable value for the neutron lifetime. The progress towards realizing a neutron lifetime measurement using a Ioffe-type trap made with a Halbach-type permanent octupole magnet is presented here. The experimental procedure extracts a gas of UCNs into vacuum, which reduces many known channels of neutron losses, and detects the neutron decays via in-situ detection of the produced protons.

Leung, Kent

2008-01-01

235

Observation of Octupole Driven Resonance Phenomena with Space Charge at the CERN Proton Synchrotron  

CERN Multimedia

Several benchmarking space charge experiments have been performed during the last few years in the CERN Proton Synchrotron. These controlled experiments are of paramount importance to validate the present very powerful simulation codes. The observations of the combined effect of space charge and nonlinear resonance on beam loss and emittance, using a single controllable octupole during ~ 1 s at 1.4 GeV kinetic energy, are discussed in some detail in the present paper. By lowering the working point towards the octupolar resonance, a gradual transition from a regime of loss-free core emittance blow-up to a regime of continuous loss was found.

Métral, E; Martini, M; Steerenberg, R; Franchetti, Giuliano; Hofmann, I

2006-01-01

236

Coupling of the octupole vibration to the single particle and hole states around {sup 208}Pb  

Energy Technology Data Exchange (ETDEWEB)

The neutron reach isotopes populated in the {sup 136}Xe and {sup 208}Pb heavy ion reactions on the {sup 208}Pb target. Experiment has been carried out at the Unilac accelerator at GSI Darmstadt. The energy of beams was 6.5 MeV/u. Gamma quanta have been detected using EUROBALL HPGe-cluster detectors and CRYSTAL BALL NaI array used to measure coincident gamma rays. Energies of excited states identified as the octupole vibration coupled to single particle and hole states and energies of E3 gamma transitions have been found. 3 refs, 1 fig., 1 tab.

Rejmund, M. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)]|[Warsaw Univ., Inst. of Experimental Physics, Nuclear Physics Div., Warsaw (Poland); Maier, K.H. [Hahn-Meitner-Institut Berlin GmbH, Berlin (Germany); Agramunt, J. [Instituto de Fisica Corpuscular, Valencia (Spain)] [and others

1997-12-31

237

Possible experimental evidence for the presence of double octupole states in {sup 240}Pu  

Energy Technology Data Exchange (ETDEWEB)

Excited states in the {sup 240}Pu nucleus have been studied by means of the (p,t) reaction using the Q3D spectrometer and the focal plane detector from Munich. The comparison between experimental angular distributions and the DWBA calculations allowed the extraction of relative two-neutron transfer strengths. These observables may reveal important information about the structure of different states. The experimental two neutron strength for the 0{sup +}{sub 2} and 0{sup +}{sub 3} states is found in good agreement with the predictions of the IBA model, confirming the double octupole nature for the 0{sup +}{sub 2} state proposed in the previous studies.

Pascu, S.; Spieker, M.; Bucurescu, D.; Faestermann, T.; Hertenberger, R.; Skalacki, S.; Weber, S.; Wirth, H. F.; Zamfir, N. V.; Zilges, A. [Institut fuer Kernphysik, Universitaet zu Koeln, D-50937 Koeln, Germany and National Institute for Physics and Nuclear Engineering, R-77125, Bucharest-Magurele (Romania); Institut fuer Kernphysik, Universitaet zu Koeln, D-50937 Koeln (Germany); National Institute for Physics and Nuclear Engineering, R-77125, Bucharest-Magurele (Romania); Physik Department E12, Technische Universitaet Muenchen, D-85748 Garching (Germany); Sektion Physik, Ludwig-Maximilians-Universitaet Muenchen, D-85748 Garching (Germany); Institut fuer Kernphysik, Universitaet zu Koeln, D-50937 Koeln (Germany); Sektion Physik, Ludwig-Maximilians-Universitaet Muenchen, D-85748 Garching (Germany); National Institute for Physics and Nuclear Engineering, R-77125, Bucharest-Magurele (Romania); Institut fuer Kernphysik, Universitaet zu Koeln, D-50937 Koeln (Germany)

2012-10-20

238

Anharmonicities in the vibrational spectra in deformed nuclei  

International Nuclear Information System (INIS)

Several experimental results have recently raised again the problem of the description of the anharmonicities of the vibrations observed in even-even deformed nuclei. They are very briefly recalled together with some of their interpretations. The multiphonon method has been developed to improve two approaches in two aspects: the Pauli principle is properly treated and exact diagonalisation within collective space is used. A sketch of this method is given. It is illustrated by the description of octupole vibrations in the Ra - Th region. Other possible applications are also indicated.

1984-01-01

239

Mobility of vacancies under deformation and their effect on the elastic properties of graphene  

Energy Technology Data Exchange (ETDEWEB)

The effect of isolated vacancies on the elastic properties of a graphene sheet has been investigated by the ab initio density functional method. An almost inverse linear dependence of the Young's modulus on the concentration of vacancies has been revealed. The height of potential barriers for the motion of vacancies in various directions has been calculated as a function of various independent applied strains. The velocity of vacancies at various temperatures has been calculated as a function of applied strains using the transition state theory.

Fedorov, A. S., E-mail: alex99@iph.krasn.ru [Russian Academy of Sciences, Kirensky Institute of Physics, Siberian Branch (Russian Federation); Fedorov, D. A. [Siberian Federal University (Russian Federation); Popov, Z. I. [Russian Academy of Sciences, Kirensky Institute of Physics, Siberian Branch (Russian Federation); Anan' eva, Yu. E.; Eliseeva, N. S. [Siberian Federal University (Russian Federation); Kuzubov, A. A. [Russian Academy of Sciences, Kirensky Institute of Physics, Siberian Branch (Russian Federation)

2011-05-15

240

Thermomechanical properties and deformation of coarse-grained models of hard-soft block copolymers  

Science.gov (United States)

In this paper, we investigate the enhancement mechanism of the mechanical properties for hard-soft block copolymers by using molecular dynamics simulations at various temperatures. A coarse-grained approach is adopted to study sufficiently generic models. Our numerical experiments demonstrate that the nonbond potential plays a more significant role in mechanical properties compared to the bond potential. This finding serves as a cornerstone to understand the hard-soft materials. To explore the effect of hard segments, four copolymers with different concentrations and energy factors that describe the interaction between hard beads are conducted. Simulation results show that the mechanical performances of the system with large attractive force and small concentration of hard segments could be improved dramatically in conjunction with a moderate increment of the glass transition temperature. In particular, the energy factor shows a substantial influence in determining the microphase separation as well as the morphology of hard domains. These observations are believed to provide design guidelines for polymeric materials in engineering practice.

Cui, Zhiwei; Brinson, L. Catherine

2013-08-01

 
 
 
 
241

Ab initio calculations of the magnetic properties of perovskites under deformation  

Energy Technology Data Exchange (ETDEWEB)

Materials with perovskite and perovskite-like structures demonstrate a broad spectrum of physical properties. Colossal magnetoresistance, ferroelectricity, multiferroicity, superconductivity, charge ordering, metal-insulator transition, Jahn-Teller and other effects are observed in perovskites. These properties of the mentioned materials with the common formula ABO{sub 3} are very sensitive to the type of the cations A and B. La{sub 2/3}Sr{sub 1/3}MnO{sub 3} (LSMO) is a strongly correlated 3d transition metal oxide with a Curie temperature (T{sub C}) above RT (370 K). For other La/Sr ratios different types of antiferromagnetism are observed. Other perovskite, ruthenate SrRuO{sub 3} (SRO) is a 4d ferromagnet with T{sub C} = 160 K. Here we perform ab initio calculations for LSMO and SRO in ideal cubic, tetragonally distorted, and different orthorhombic structures. We focus on magnetic order and Curie temperature of the above mentioned structures in the different structural phases.

Maznichenko, Igor [Institut fuer Physik, Martin-Luther-Universitaet Halle-Wittenberg, Halle (Saale) (Germany); Etz, Corina; Ernst, Arthur [Max-Planck-Institut fuer Mikrostrukturphysik, Halle (Saale) (Germany); Lueders, Martin; Szotek, Zdzislawa; Temmerman, Walter [Daresbury Laboratory, Daresbury, Warrington, Cheshire (United Kingdom); Mertig, Ingrid [Institut fuer Physik, Martin-Luther-Universitaet Halle-Wittenberg, Halle (Saale) (Germany); Max-Planck-Institut fuer Mikrostrukturphysik, Halle (Saale) (Germany)

2010-07-01

242

Small and large deformation viscoelastic behaviour of selected fibre blends with gelling properties  

UK PubMed Central (United Kingdom)

Dietary fibres can be used as valuable functional ingredients in baked goods, as thickeners and gelling agents as a result of their ability to modify the structural properties of the matrix in which they are embedded. Viscoelastic behaviour of 12 selected gel-fibre blends (carboxymethylcellulose, hydroxypropylmethylcellulose, locust bean gum, high ester pectin, fructo-oligosaccharide and gluco-oligosaccharide) prepared at 10% concentration (w/v) was investigated at 25^oC and 95^oC by applying both fundamental and empirical rheological techniques to explore their usefulness/suitability as structural ingredients in diluted and weakened baking systems such as gluten free matrices. Mechanical and thermo-mechanical properties were recorded by using a controlled stress rheometer, measuring the storage modulus (G'), the loss modulus (G'') and the complex viscosity (@h*). Textural characteristics were assessed by using a TAXTplus Texture Analyser with different attachments. Penetration and back extrusion tests were used for solid and liquid-like samples, respectively. The overall results indicated that (i) carboxymethylcellulose and pectin formed the strongest and the weakest gels, respectively, and that (ii) temperature had a significant effect on gel strength improvement especially for locust bean gum. A 30% substitution of hydrated fibres (cellulose derivates, galactomanans and high ester pectin) by prebiotics (fructo-oligosaccharides and gluco-oligosaccharides) led to a significant decrease of gel structure rigidity when compared to an identical system without prebiotic addition. Only locust bean gum exhibited an opposite behaviour inducing an increase in values of both dynamic moduli (G' and G'') and static hardness. Significant relationships between dynamic (rheometry) and static (texture analysis) methods were found. Strengthening and structuring ability of some fibre blend gels endorsed them to be used as promising functional ingredients to make gluten-free bread by using low cost thickeners' agents.

Angioloni Alessandro; Collar Concha

2009-05-01

243

Tetrahedral and Triangular Deformations of $Z=N$ Nuclei in Mass Region $A \\sim 60-80$  

CERN Document Server

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

Takami, S; Matsuo, M

1998-01-01

244

Influence of processing temperature on microstructural and mechanical properties of high-alloyed single-phase steels subjected to severe plastic deformation  

Energy Technology Data Exchange (ETDEWEB)

An austenitic and a ferritic steel were subjected to severe plastic deformation at 20 and 450 deg. C up to equivalent strains of 32. The development of the microstructure and the mechanical properties have been investigated by capturing back-scattered electron micrographs and performing subsize tensile tests. For both steels, a steady state of the properties was observed above equivalent strains of 16. The results show clearly that the temperature influences both, microstructure and mechanical properties, whereas the type of material (ferritic, austenitic) plays an additional important role. Possible reasons for the observed differences are discussed.

Vorhauer, A. [Christian Doppler Laboratory for Local Analysis of Deformation and Fracture and Erich Schmid-Institute of Materials Science, Austrian Academy of Sciences, Jahnstrasse 12, 8700 Leoben (Austria)]. E-mail: vorhauer@unileoben.ac.at; Kleber, S. [Boehler Edelstahl GmbH, 8605 Kapfenberg (Austria); Pippan, R. [Christian Doppler Laboratory for Local Analysis of Deformation and Fracture and Erich Schmid-Institute of Materials Science, Austrian Academy of Sciences, Jahnstrasse 12, 8700 Leoben (Austria)

2005-11-25

245

Influence of processing temperature on microstructural and mechanical properties of high-alloyed single-phase steels subjected to severe plastic deformation  

International Nuclear Information System (INIS)

[en] An austenitic and a ferritic steel were subjected to severe plastic deformation at 20 and 450 deg. C up to equivalent strains of 32. The development of the microstructure and the mechanical properties have been investigated by capturing back-scattered electron micrographs and performing subsize tensile tests. For both steels, a steady state of the properties was observed above equivalent strains of 16. The results show clearly that the temperature influences both, microstructure and mechanical properties, whereas the type of material (ferritic, austenitic) plays an additional important role. Possible reasons for the observed differences are discussed

2005-11-25

246

Construction and Operational Experience with a Superconducting Octupole Used to Trap Antihydrogen  

Energy Technology Data Exchange (ETDEWEB)

A superconducting octupole magnet has seen extensive service as part of the ALPHA experiment at CERN. ALPHA has trapped antihydrogen, a crucial step towards performing precision measurements of anti-atoms. The octupole was made at the Direct Wind facility by the Superconducting Magnet Division at Brookhaven National Laboratory. The magnet was wound with a six-around-one NbTi cable about 1 mm in diameter. It is about 300 mm long, with a radius of 25 mm and a peak field at the conductor of 4.04 T. Specific features of the magnet, including a minimal amount of material in the coil and coil ends with low multipole content, were advantageous to its use in ALPHA. The magnet was operated for six months a year for five years. During this time it underwent about 900 thermal cycles (between 4K and 100K). A novel operational feature is that during the course of data-taking the magnet was repeatedly shut off from its 950 A operating current. The magnet quenches during the shutoff, with a decay constant of 9 ms. Over the course of the five years, the magnet was deliberately quenched many thousands of times. It still performs well.

Wanderer P.; Escallier, J.; Marone, A.; Parker, B.

2011-09-06

247

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

Science.gov (United States)

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.

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

2007-05-01

248

Self-consistent study of deformation properties of even cadmium isotopes in the vicinity of the N=50 magic number  

International Nuclear Information System (INIS)

[en] Deformation energy curves of 98Cd, 102Cd, 196Cd, 110Cd isotopes have been performed using the Skyrme SIII effective interaction. With the exception of the neutron magic 98Cd isotope, these nuclei are found -in the purely static calculations- to be soft, prolate shaped and moderately deformed at equilibrium

1979-01-01

249

Geometrical and mechanical properties of the fractures and brittle deformation zones based on ONKALO tunnel mapping, 0-2400 m tunnel chainage  

International Nuclear Information System (INIS)

In this report, the rock mechanics parameters of fractures and brittle deformation zones in the vicinity of the ONKALO area have been estimated, the analysed data being from the ONKALO tunnel over the chainage range 0-2400 m. Some analysis has also been made based on core logging data from the drillholes OL-KR1-OL-KR40. At this stage, the main objective of the work is to obtain preliminary parameters for the rock mechanics simulations and the rock mechanics design. In this report, the rock mechanics parameters of the fractures are mainly 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. The fracture wall compressive strength (JCS) has been systematically estimated for the chainage range 1280-2400 m using Schmidt hammer tests. So far, only a few laboratory direct shear tests have been conducted on fracture samples. Estimation of the mechanics properties of the 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. The intact rock strength of the brittle deformation zones has been evaluated using Schmidt hammer tests. (orig.)

2010-01-01

250

Properties of seven-filament in situ MgB2/Fe composite deformed by hydrostatic extrusion, drawing and rolling  

International Nuclear Information System (INIS)

[en] Seven-filament MgB2/Fe wires and tapes were made by in situ processing using hydrostatic extrusion, rolling and drawing. Microhardness measurements have shown that the density of as-deformed cores reflects the applied deformation and follows the iron sheath hardness. The filament size was reduced from 245 ?m down to 19 ?m by rolling and the critical current densities of samples with different core sizes and deformation routes were compared. The highest current density was measured for the tape deformed by two-axial rolling and a filament size of 60 ?m. Thinner filaments show lower Jc values due to hard inclusions present in low-purity boron powder (boron oxide), which reduce the transport current substantially. The obtained results show that a proper combination of extrusion and rolling deformations leads to high filament density in wires and tapes, which results in high transport current density

2007-01-01

251

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)

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)

Louis, L.

2003-10-15

252

Proton-neutron structure of the effective quadrupole-octupole coupled E1 transition operator  

International Nuclear Information System (INIS)

[en] Electric dipole transitions between 31- octupole-phonon states and one-phonon 21,ms+ mixed-symmetry states of 92Zr, 94Mo, 96Ru, and 142Ce are observed and provide the first evidence for F-vector E1 transitions in nuclei. For effective boson models of the nuclear valence shell, F spin is the analog of isospin in the shell model. The 31-?21,ms+ E1 transitions are stronger than those of the 21+ state. The effective E1 operator in the sdf-interacting boson model-2 is concluded to have F-vector character, in analogy with the well-known isovector character of the E1 operator in microscopic models

2003-01-01

253

New results for the missing quantum numbers labeling the quadrupole and octupole boson basis  

CERN Multimedia

The many $2^k$-pole boson states, $|N_kv_k\\alpha_k I_kM_k>$ with $k=2,3$, realize the irreducible representation (IR) for the group reduction chains $SU(2k+1)\\supset R_{2k+1}\\supset R_3\\supset R_2$. They have been analytically studied and widely used for the description of nuclear systems. However, no analytical expression for the degeneracy $d_v(I)$ of the $R_{2k+1}$'s IR, determined by the reduction $R_{2k+1}\\supset R_3$, is available. Thus, the number of distinct values taken by $\\alpha_k$ has been so far obtained by solving some complex equations. Here we derive analytical expressions for the degeneracy $d_v(I)$ characterizing the octupole and quadrupole boson states, respectively. The merit of this work consists of the fact that it completes the analytical expressions for the $2^k$-pole boson basis.

Gheorghe, A

2004-01-01

254

Low-lying collective quadrupole and octupole strengths in even-even nuclei  

International Nuclear Information System (INIS)

The B(E2)? values for the first 2+ state of even-even nuclei in the Z?50 region are compared with the predictions of several theoretical models. Comparative estimates of the overall agreement with the data are provided. Gaps and discrepancies in the data and examples that show interesting features such as shape changes are discussed. The B(E2)? values are examined critically to search for the dynamical Pauli effects predicted by the fermion dynamic symmetry model. The empirical B(E2)? and B(E3)? systematics are employed to obtain a measure of the harmonicity of the quadrupole and octupole vibrations. The fraction of the energy-weighted sum-rule strength exhausted by the sum of all known low-lying 2+ states below 2.3 MeV is found to be surprisingly constant in the 60

1991-01-01

255

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.

2004-01-01

256

Ultrafine-Grained Aluminum Processed by a Combination of Hot Isostatic Pressing and Dynamic Plastic Deformation: Microstructure and Mechanical Properties  

Science.gov (United States)

Commercial-purity (99 wt pct), bulk, ultrafine-grained aluminum samples were produced by a two-step process that combines powder consolidation by hot isostatic pressing and dynamic plastic deformation. The compaction step yielded crystallographic texture-free specimens with an average grain size of approximately 2 ?m. Then, some of the consolidated specimens were deformed dynamically at room temperature at an initial strain rate of 370 seconds-1 and up to an axial strain of ? = 1.25. After dynamic plastic deformation, the grain size and the dislocation density were approximately 500 nm and 1014 m-2, respectively. The yield strength was approximately 77 MPa for the as-consolidated sample, which increased up to approximately 103 MPa and 120 MPa for the impacted samples along the axial and radial directions, respectively. The compression stress as a function of strain showed saturation behavior for the axially deformed samples, whereas the specimens deformed along the radial direction exhibited significant strain softening. The latter behavior is explained mainly by the weakening of the crystallographic texture that occurred because of the strain-path change along the radial direction.

Dirras, G.; Chauveau, T.; Abdul-Latif, A.; Gubicza, J.; Ramtani, S.; Bui, Q.; Heged?s, Z.; Bacroix, B.

2012-04-01

257

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

Directory of Open Access Journals (Sweden)

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.

S. Choudhary; S. Qureshi

2011-01-01

258

Intrinsic states of deformed odd-A nuclei in the mass regions (151?A?193) and (A?221)  

International Nuclear Information System (INIS)

A review of the empirical data on intrinsic states of odd-A nuclei in the mass range 151?A?193 and A?221 is presented. Global summaries of the data are presented in tables for each isotopic and isotonic chain, wherein the excitation energy, the logft values, the moment-of-inertia parameter, and the decoupling parameter (for K=1/2 bands) are listed for single-particle, vibrational admixed, and pure vibrational states. Similar data are separately presented for three-quasiparticle excitations in the rare-earth region. Taking guidance from the systematics on nuclear deformation, the single-particle deformed potential for axially symmetric and reflection-symmetric shapes (the Nilsson model) modified by the hexadecapole deformation is used to interpret the data. Other variations of the Nilsson model, which include axially asymmetric shapes (? deformation) and especially reflection-asymmetric shapes (octupole deformation), have also been used to interpret the data in certain limited regions. Systematics for the intrinsic excitations are presented and discussed in terms of these models. The newly emerging regions of the octupole-quadrupole deformation and superdeformation are also discussed.

1990-01-01

259

Intrinsic states of deformed odd- A nuclei in the mass regions (151 le A le 193) and ( A ge 221)  

Energy Technology Data Exchange (ETDEWEB)

A review of the empirical data on intrinsic states of odd-{ital A} nuclei in the mass range 151{le}{ital A}{le}193 and {ital A}{ge}221 is presented. Global summaries of the data are presented in tables for each isotopic and isotonic chain, wherein the excitation energy, the log{ital ft} values, the moment-of-inertia parameter, and the decoupling parameter (for {ital K}=1/2 bands) are listed for single-particle, vibrational admixed, and pure vibrational states. Similar data are separately presented for three-quasiparticle excitations in the rare-earth region. Taking guidance from the systematics on nuclear deformation, the single-particle deformed potential for axially symmetric and reflection-symmetric shapes (the Nilsson model) modified by the hexadecapole deformation is used to interpret the data. Other variations of the Nilsson model, which include axially asymmetric shapes ({gamma} deformation) and especially reflection-asymmetric shapes (octupole deformation), have also been used to interpret the data in certain limited regions. Systematics for the intrinsic excitations are presented and discussed in terms of these models. The newly emerging regions of the octupole-quadrupole deformation and superdeformation are also discussed.

Jain, A.K. (Departments of Chemistry and Physics, Florida State University, Tallahassee, Florida 32306 (USA) Department of Physics, University of Roorkee, Roorkee 247667, (India)); Sheline, R.K. (Departments of Chemistry and Physics, Florida State University, Tallahassee, Florida 32306 (USA)); Sood, P.C. (Departments of Chemistry and Physics, Florida State University, Tallahassee, Florida 32306 (USA) Department of Physics, Banaras Hindu University, Varanasi 221005 (India)); Jain, K. (Departments of Chemistry and Physics, Florida State University, Tallahassee, Florida 32306 (USA) Department of Physics, University of Roorkee, Roorkee 247667 (India))

1990-04-01

260

Is nucleon deformed?  

International Nuclear Information System (INIS)

[en] 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

1992-01-01

 
 
 
 
261

Plastic deformation of Fe-Al polycrystals strengthened with Zr-containing Laves phases Part II. Mechanical properties  

International Nuclear Information System (INIS)

Fe-10 at.% Al-2.5 at.% Zr and Fe-20 at.% Al-2.5 at.% Zr alloys were deformed between room temperature and 700 deg. C. The materials show a flow stress plateau at about 300 MPa up to 600 deg. C for the material with 10 at.% Al and above 600 MPa up to 400 deg. C for the alloy with 20% Al. The high flow stresses compared to Fe-Al reference materials are partly due to the addition of Zr. The strain rate sensitivity of the flow stress was measured by stress relaxation and strain rate cycling tests. It is low up to 400 deg. C and high between 450 and 600 deg. C, i.e. in the range of the flow stress decrease. The microstructures of the undeformed materials are described in Part I of this paper. Micrographs of the deformed specimens taken in a high-voltage electron microscope reveal that the deformation occurs mainly within the soft Fe-Al grains and in the Fe-Al component of the grain boundary eutectic. The deformation data are interpreted in terms of solution hardening from the Al solute, dynamic strain ageing due to the Cottrell effect of the same defects, the athermal stress component of elastic dislocation interactions, the Hall-Petch contribution from the grain size, and the strengthening effect of the grain boundary layers.

2004-09-15

262

Application of the multiphonon method to the study of the vibrational states with K = 0 in heavy deformed nuclei  

Energy Technology Data Exchange (ETDEWEB)

The multiphonon method based on K/sup ..pi../ = 0/sup -/ and K/sup ..pi../ = 0/sup +/ phonons is applied to heavy mass deformed even nuclei, such as Th, U, and Pu isotopes. Special emphasis is put on the location and properties of the ''two phonon'' states. Relative to an harmonic situation, the calculated energy spectra are systematically dilated. The octupole vibrations with K/sup ..pi../ = 0/sup -/ present larger anharmonicities than the vibrations K/sup ..pi../ = 0/sup +/ which, in these nuclei, are found to be mainly of pairing nature. The two modes appear to be weakly coupled. The ''two phonon'' states are predicted to have an energy of about 1.7 to 2.0 MeV and keep some collective character through their electromagnetic transitions to the ''one phonon'' states. These conclusions are at variance with those of the quasiparticle phonon nuclear model of Soloviev et al.

Leandri, J.; Piepenbring, R.

1988-06-01

263

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

CERN Multimedia

The interrelation between the octupole phonon and the low-lyingproton-neutron mixed-symmetry quadrupole phonon in near-spherical nuclei isinvestigated. The one-phonon states decay by collective E3 and E2 transitionsto the ground state and by relatively strong E1 and M1 transitions to theisoscalar 2^+ state. We apply the proton-neutron version of the InteractingBoson Model including quadrupole and octupole bosons (sdf-IBM-2). Two F-spinsymmetric dynamical symmetry limits of the model, namely the vibrational andthe $\\gamma$-unstable ones, are considered. We derive analytical formulae forexcitation energies as well as B(E1), B(M1), B(E2) and B(E3) values for anumber of transitions between low-lying states. The model well reproduces manyknown transition strengths in the near spherical nuclei ^{142}Ce and ^{94}Mo.

Smirnova, N A; Mizusaki, T; Van Isacker, P; Smirnova, Nadya A.; Pietralla, Norbert; Mizusaki, Takahiro; Isacker, Piet Van

2000-01-01

264

Octupole excitations in 141,144Cs and the pronounced decrease of dipole moments with neutron number in odd-Z neutron-rich 141,143,144Cs  

International Nuclear Information System (INIS)

The level scheme of odd-Z neutron-rich 141Cs (Z=55, N=86) was extended and expanded and that of 144Cs (N=89) was identified for the first time by means of ?-?-? coincidence measurements of prompt ? rays in the spontaneous fission of 252Cf with Gammasphere. Spin/parity was assigned to the levels based on angular correlations and level systematics in 141,143Cs. Parity doublets characteristic of both simplex quantum number s=+i and s=-i were proposed in 141Cs. The tests by using rotational frequency ratio ?-(I)/?+(I) imply octupole vibrations in 141Cs and 143Cs. B(E1)/B(E2) values and electric dipole moments D0 were calculated for 141Cs, and re-determined for 143Cs. It was found that B(E1)/B(E2) values of 141Cs are simplex-dependent and the average value is one order of magnitude larger than that of 143Cs, and the deduced dipole moment D0 of 141Cs is considerably larger than that of 143Cs, and comparable to the N=86 isotone 142Ba. For 144Cs the yrast sequence looks like a well-deformed rotational band, but no octupole band structure was identified in this nucleus. The overall variations of D0 in 141,143,144Cs 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 D0 observed in even-even 146Ba (Z=56, N=90) and 224Ra (Z=88, N=136), and to the drop of D0 in the odd-Z neutron-rich 147La (Z=57, N=90) reported by our collaboration.

2010-07-01

265

The in situ measurement of the effect of plastic deformation on the magnetic properties of steel. Part I. Hysteresis loops and magnetostriction  

International Nuclear Information System (INIS)

[en] We report measurements of the bulk magnetic properties of pearlitic steels recorded in-situ during plastic deformation. Hysteresis loops were initially found to become squarer but became less so as the stress increased. Magnetostrictive measurements revealed that the low field region showed zero magnetostriction, while the change to magnetisation vector rotations was shown to take place at lower magnetisation values with increasing tension. The coercive field remained constant or decreased with increasing stress at lower values of tension, but higher stress levels produced an increase attributed to new pinning sites generated by the plastic deformation process. This increase, proportional to the square of the stress, was seen to initiate before yield, rather than at the yield point. Remnant magnetisation was found to increase at lower tension levels, but higher stress levels produced a decrease in value that was attributed to stress induced changes in magnetic anisotropy. The high field magnetisation decreased monotonically with stress in both the pre-yield and plastically deformed regions. (orig.)

1998-01-01

266

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

DEFF Research Database (Denmark)

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.

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

2013-01-01

267

Octupole vibration in the superdeformed {sup 196}Pb nucleus; Vibration octupolaire dans le noyau superdeforme {sup 196}Pb  

Energy Technology Data Exchange (ETDEWEB)

The study of the superdeformed (SD) {sup 196}Pb nucleus has been revisited using the EUROGAM phase 2 spectrometer. All the three observed excited SD bands were found to decay to the Yrast SD band through, presumably, E1 transitions, allowing relative spin and excited energy assignments. Comparisons with calculation using the random phase approximation suggests that all three excited bands can be interpreted as octupole vibrational structures. (authors) 5 refs., 1 fig.

Bouneau, S.; Azaiez, F.; Duprat, J. [Experimental Research Division, Inst. de Physique Nucleaire, Paris-11 Univ., 91 - Orsay (France)] [and others

1999-11-01

268

Measurement of reduced electric octupole transition probabilities B(E3;O1+ ? 31-), for 118,120,122Sn  

International Nuclear Information System (INIS)

[en] Values of reduced electric octupole transition probabilities B(E3;O1+ ? 31-) for the nuclides 118,120,122Sn have been determined using Coulomb excitation with 12C projectiles. The results are in good agreement with shell-model calculations made without introducing effective charges but involving core excitations. Values for B(E2;O1+ ? 21+) are also presented

1988-01-01

269

Measurement of reduced electric octupole transition probabilities, B (E3;01+ ? 31-), for 118,120,122Sn  

International Nuclear Information System (INIS)

Values of reduced electric octupole transition probabilities, B(E3;01+ ? 31-), for the nuclides 118,120,122Sn have been determined using Coulomb excitation with 12C projectiles. The results are in good agreement with shell-model calculations made without introducing effective charges but involving core excitations. Values for B (E2;01+ ? 21+) are also presented. 20 refs., 2 figs., 3 tabs

1989-01-01

270

Study of influence of isothermal plastic deformation with low strain rates on structure and properties of ZhS6KP nickel alloy  

International Nuclear Information System (INIS)

A study was made into the possibility to increase fatigue strength and long-term rupture strength with preservation of short-term mechanical properties in heat-resistant alloy type ZhS6KP due to plastic deformation with low rates before heat treatment. It was shown that hot working at 1160 deg C with 6-10% reduction and low strain rates with subsequent air quenching (1160 deg C, 4 h) and ageing (950 deg C, 2 h) allows to increase the time to fracture by a factor of 1.5 and fatigue strength by 50 N/mm2. 3 tabs.

1996-01-01

271

q-deformed Brownian motion  

CERN Document Server

Brownian motion may be embedded in the Fock space of bosonic free field in one dimension.Extending this correspondence to a family of creation and annihilation operators satisfying a q-deformed algebra, the notion of q-deformation is carried from the algebra to the domain of stochastic processes.The properties of q-deformed Brownian motion, in particular its non-Gaussian nature and cumulant structure,are established.

Man'ko, V I

1993-01-01

272

Deformation processing of HTS wire  

Energy Technology Data Exchange (ETDEWEB)

Methods to understand, control, and optimize deformation processing of HTS wire are outlined. Topics discussed include: technical progress, deformation processing effects on HTS - core uniformity in composite tapes, effects of rolling on tapes, deformation process modeling, channel die powder compaction stress-strain data, microhardness versus rolling reduction, minimum bifurcation strain versus material state, roll gap geometries for large versus small rolls, interactions, hydrostatic extrusion, and tensile properties.

Bingert, J. [Los Alamos National Lab., NM (United States)

1994-07-29

273

Plastic deformation characteristic properties of irradiated austenite corrosion-resistant steels in the temperature range 20...450 degree C  

International Nuclear Information System (INIS)

[en] The main signs of the low-temperature radiation embrittlement of structural materials are described; the effect of the crystalline lattice type, of the test temperature and of the irradiation dose,of deformation rate, of the microalloying by REth, of the metal purity on the low temperature radiation embrittlement is considered. The influence of the neutron irradiation dose on the plastic deformation of steels and alloys in the temperature range of low-temperature radiation embrittlement is studied. The diagram of the ultimate strength and the yield point, of the elongation change of austenite structural materials in dependence on the irradiation dose,on the dislocation density and on the nickel content is proposed. The methods of the increase of the austenite steels and alloys resistance to the low temperature radiation embrittlement are considered

2003-01-01

274

Some unusal properties of the fine structure of dislocations in Ni{sub 3}Al deformed at high temperature  

Energy Technology Data Exchange (ETDEWEB)

In Ni{sub 3}Al polycrystals deformed at 850{degrees}C and quenched rapidly, surface defects exhibit two kinds of behaviour. On the one hand, dislocation coupling by antiphase boundary (APB) and complex stacking fault (CSF) is of normal magnitude for this alloy composition. On the other hand, separations are dramatically decreased in both cases. A method to visualize antiphase boundaries using a weakly excited superlattice reflection is introduced.

Veyssiere, P. [Office National d`Etudes et de Recherches Aerospatiales (ONERA), 92 - Chatillon (France); Horton, J.A. [Oak Ridge National Lab., TN (United States)

1994-12-31

275

Search for the two-phonon octupole vibrational state in {sup 208}Pb  

Energy Technology Data Exchange (ETDEWEB)

We 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 were bombard {sup 208}Pb supplied by ATLAS. Gamma rays were detected using the Argonne-Notre Dame BGO gamma-ray facility, consisting of 12 Compton-suppressed germanium detectors surrounding an array of 50 BGO scintillators. We identified some 30 known gamma rays from {sup 208}Pb in the spectra gated by the 5{sup -} {yields} 3{sup -} and 3{sup -} {yields} 0{sup +} transitions in {sup 208}Pb. In addition, after unfolding these spectra for Compton response, we observed broad coincident structures in the energy region expected for the 2-phonon states. Furthermore, we confirmed the placement of a 2485 keV line observed previously in {sup 207}Pb and find no evidence consistent with the placement of this line in {sup 208}Pb. We are currently in the process of investigating the origin of the broadened lines observed in the spectra, extracting the excitation probability of states in {sup 208}Pb, and determining the relative probability of mutual excitation and neutron transfer in this reaction. An additional experiment is also being performed to collect much higher statistics germanium-germanium coincidence data for the thick {sup 208}Pb target.

Blumenthal, D.J.; Henning, W.; Janssens, R.V.F. [and others

1995-08-01

276

Low-lying collective quadrupole and octupole strengths in even-even nuclei  

Energy Technology Data Exchange (ETDEWEB)

The {ital B}({ital E}2){up arrow} values for the first 2{sup +} state of even-even nuclei in the {ital Z}{ge}50 region are compared with the predictions of several theoretical models. Comparative estimates of the overall agreement with the data are provided. Gaps and discrepancies in the data and examples that show interesting features such as shape changes are discussed. The {ital B}({ital E}2){up arrow} values are examined critically to search for the dynamical Pauli effects predicted by the fermion dynamic symmetry model. The empirical {ital B}({ital E}2){up arrow} and {ital B}({ital E}3){up arrow} systematics are employed to obtain a measure of the harmonicity of the quadrupole and octupole vibrations. The fraction of the energy-weighted sum-rule strength exhausted by the sum of all known low-lying 2{sup +} states below 2.3 MeV is found to be surprisingly constant in the 60{lt}{ital A}{lt}250 region except near closed shells.

Raman, S.; Nestor, C.W. Jr. (Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (US)); Kahane, S. (Joint Institute for Heavy-Ion Research, Holifield Heavy Ion Research Facility, Oak Ridge, Tennessee 37831 (USA)); Bhatt, K.H. (Department of Physics and Astronomy, University of Mississippi, University, Mississipi 38677 (USA))

1991-02-01

277

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 B(E1) values increase with spin. 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 bandcrossings and configurations of these bands are discussed by TRS and CSM calculations. In a ?-?-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. (orig.).

1998-01-01

278

Non-yrast nuclear spectra in a model of coherent quadrupole-octupole motion  

CERN Multimedia

A model assuming coherent quadrupole-octupole vibrations and rotations is applied to describe non-yrast energy sequences with alternating parity in several even-even nuclei from different regions, namely $^{152,154}$Sm, $^{154,156,158}$Gd, $^{236}$U and $^{100}$Mo. Within the model scheme the yrast alternating-parity band is composed by the members of the ground-state band and the lowest negative-parity levels with odd angular momenta. The non-yrast alternating-parity sequences unite levels of $\\beta$-bands with higher negative-parity levels. The model description reproduces the structure of the considered alternating-parity spectra together with the observed B(E1), B(E2) and B(E3) transition probabilities within and between the different level-sequences. B(E1) and B(E3) reduced probabilities for transitions connecting states with opposite parity in the non-yrast alternating-parity bands are predicted. The implemented study outlines the limits of the considered band-coupling scheme and provides estimations ab...

Minkov, N; Strecker, M; Scheid, W; Lenske, H; 10.1103/PhysRevC.85.034306

2012-01-01

279

Delta I = 1 staggering in octupole bands of light actinides "Beat" patterns  

CERN Multimedia

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.

Bonatsos, Dennis; Drenska, S B; Karoussos, N; Minkov, N; Raychev, P P; Roussev, R P

2001-01-01

280

Spinal deformity.  

UK PubMed Central (United Kingdom)

Spinal deformity is a relatively common disorder, particularly in teenage girls. Early detection is possible by a simple, quick visual inspection that should be a standard part of the routine examination of all preteen and teenage patients. Follow-up observation will reveal those curvatures that are progressive and permit orthotic treatment to prevent further increase in the deformity. Spinal fusion offers correction and stabilization of more severe degrees of scoliosis.

Bunnell WP

1986-12-01

 
 
 
 
281

Alteration by procaine of spectrin cross-links, deformability, and fluidity related properties of the erythrocyte membrane.  

Science.gov (United States)

The study on procainized human erythrocytes revealed a) temperature dependent changes of cellshapes, b) a significant increase of deformability, c) low amounts of cross-linked membrane proteins, d) a mean cell volume identical with the volume of nonprocainized cells, e) severe reduction of induced anisotropy, f) no loss of negatively charged groups of the glycocalyx, g) decrease of electrophoretic velocity, h) a significant rise of adhesiveness to glass, and i) increase of agglutinability with antiserum and lectin. The findings are discussed in their relationships to alterations of the molecular structure of the red cell membrane. PMID:6159284

Geyer, G; Halbhuber, K J; Stibenz, D; Scheven, C; Unger, J; Benser, A; Fröber, R; Makovitzky, J; Geiling, D; Geiling, H G

1980-01-01

282

Stressed-deformed state of the near-face bed zone having the property of linear inheritance  

Energy Technology Data Exchange (ETDEWEB)

An examination is made of the spatial axisymmetric case of deviation of the stressed deformed state of a bed which causes influx of fluid to a well which periodically changes in time. The porous bed which is stripped by an ideal well of finite radius is fused at the base and the roofing by elastic infinite massif of surrounding rocks. The ratio is between the deformations and the stresses for the porous bed are adopted in the form of integral Volterra operators whose differential nucleus is a fractional-exponential function of Yu. N. Rabotnov. Asymptotics are presented for the result of using this operator for functions which can be represented by a segment of the Fourier series. The periodic solution to the task is asymptotically constructed with the help of Weber transforms. The Volterra principle is applied at the stage of solving the functional system of equation which corresponds to the boundary conditions, in the space of Weber images. The solvability of the obtained system of integral equations is indicated.

Susokolov, A.N.

1983-01-01

283

New kinds of deformed Bessel functions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Using a deformed calculus based on the Dunkl operator, two new deformations of Bessel functions are proposed. Some properties i.e. generating function, differential-difference equation, recursive relations, Poisson formula... are also given with detailed proofs. Three more deformations are also outl...

Zahaf, Mohammed Brahim; Manchon, Dominique

284

Tuning the electronic properties of boron nitride nanotube by mechanical uni-axial deformation: a DFT study  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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,...

Ju, Shin-Pon; Wang, Yao-Chun; Lien, Ting-Wei

285

Quantum deformations  

Energy Technology Data Exchange (ETDEWEB)

I review and illustrate applications of explicit functionals we have found which map SU(2) algebra generators to those of several quantum deformations of this Lie algebra. I indicate how virtually any such quantized algebra can be mapped to any other, and how representations of such algebras can be expressed as simple functions of SU(2) representations. The representation theory and its comultiplication rules are thus systematized and streamlined by direct reference to their SU(2) correspondents, and may be rapidly surveyed. I further provide a candidate quantum deformation of the Virasoro algebra. 19 refs.

Zachos, C.K.

1990-01-01

286

Quantum deformations  

International Nuclear Information System (INIS)

[en] I review and illustrate applications of explicit functionals we have found which map SU(2) algebra generators to those of several quantum deformations of this Lie algebra. I indicate how virtually any such quantized algebra can be mapped to any other, and how representations of such algebras can be expressed as simple functions of SU(2) representations. The representation theory and its comultiplication rules are thus systematized and streamlined by direct reference to their SU(2) correspondents, and may be rapidly surveyed. I further provide a candidate quantum deformation of the Virasoro algebra. 19 refs

1990-05-11

287

Soft octupole vibrations on superdeformed states in nuclei around 40Ca suggested by Skyrme-HF and self-consistent RPA calculations  

International Nuclear Information System (INIS)

We present the results of fully self-consistent RPA calculation for low-frequency negative-parity modes built on superdeformed states in the 40Ca region. The RPA calculation was carried out using the mixed representation on the three-dimensional Cartesian mesh in a box. The SD shell structure provides a very favorable situation for octupole shape fluctuations, and we show that the coherent excitation of protons and neutrons play an important role in the emergence of strongly collective octupole vibrations built on the SD states in the N=Z nuclei, 32S, 36Ar, 40Ca and 44Ti. In particular, the calculation suggests that a low-frequency, strongly collective K?=1- octupole vibration appears on the SD state in 40Ca. (orig.)

2005-01-01

288

Structural defects in Fe-Pd-based ferromagnetic shape memory alloys: tuning transformation properties by ion irradiation and severe plastic deformation  

Science.gov (United States)

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 \\leftrightarrow 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.

Mayr, S. G.; Arabi-Hashemi, A.

2012-10-01

289

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)

[en] 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)

2012-01-01

290

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.

2009-01-01

291

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)

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.

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

292

Measurements of octupole collectivity in $^{220,222}$Rn and $^{222,224}$Ra using Coulomb excitation  

CERN Document Server

We propose to exploit the unique capability of ISOLDE to provide post-accelerated $^{220,222}$Rn and $^{222,224}$Ra ion beams from the REX facility to enable the Coulomb excitation of the first 3$^{-}$ states 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 transition matrix elements. This will give quantitative information about octupole correlations in these nuclei. We require 22 shifts to fulfil the aims of the experiment.

Gaffney, L P; Bastin, B; Kruecken, R; Larsen, A; Hurst, A M; Voulot, D; Grahn, T; Clement, E; Wadsworth, R; Gernhaeuser, R A; Siem, S; Van duppen, P L E; Page, R; Barton, C J; Wenander, F J C; Huyse, M L; Iwanicki, J S; Warr, N V

2008-01-01

293

Hyperfine structure of the metastable 3P2 state of alkaline earth atoms as an accurate probe of nuclear magnetic octupole moments  

CERN Document Server

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.

Beloy, K; Johnson, W R

2007-01-01

294

Multiscale modeling of the effect of carbon nanotube orientation on the shear deformation properties of reinforced polymer-based composites  

Energy Technology Data Exchange (ETDEWEB)

A combination of molecular dynamics (MD), continuum elasticity and FEM is used to predict the effect of CNT orientation on the shear modulus of SWCNT-polymer nanocomposites. We first develop a transverse-isotropic elastic model of SWCNTs based on the continuum elasticity and MD to compute the transverse-isotropic elastic constants of SWCNTs. These constants are then used in an FEM-based simulation to investigate the effect of SWCNT alignment on the shear modulus of nanocomposites. Furthermore, shear stress distributions along the nanotube axis and over its cross-sectional area are investigated to study the effect of CNT orientation on the shear load transfer. - Highlights: A transverse-isotropic elastic model of SWCNTs is presented. A hierarchical MD/FEM multiscale model of SWCNT-polymer composites is developed. Behavior of these nanocomposites under shear deformation is studied. A symmetric shear stress distribution occurs only in SWCNTs with 45{sup o} orientation. The total shear load sustained is greatest in the case of 45{sup o} orientation.

Montazeri, A. [Institute for Nano-Science and Technology, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Computational Physical Sciences Research Laboratory, School of Nano-Science, Institute for Research in Fundamental Sciences (IPM), Tehran (Iran, Islamic Republic of); Sadeghi, M. [Institute for Nano-Science and Technology, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Naghdabadi, R., E-mail: naghdabd@sharif.ed [Institute for Nano-Science and Technology, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Department of Mechanical Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Rafii-Tabar, H. [Computational Physical Sciences Research Laboratory, School of Nano-Science, Institute for Research in Fundamental Sciences (IPM), Tehran (Iran, Islamic Republic of); Department of Medical Physics and Biomedical Engineering, and Research Centre for Medical Nanotechnology and Tissue Engineering, Shahid Beheshti University of Medical Sciences, Evin, Tehran (Iran, Islamic Republic of)

2011-04-04

295

Effect of grain size distribution on mechanical properties of ultrafine grained Al severely deformed by ARB process and subsequently annealed  

International Nuclear Information System (INIS)

[en] A commercial purity aluminum was highly deformed by the accumulative roll-bonding (ARB) process and subsequently annealed. The specimens having various grain size distributions were obtained. In case of the specimen ARB-processed with lubrication, the specimens with mean grain size larger than 3?m showed continuous yielding. On the other hand, in case of the specimen ARB-processed without lubrication, the specimens with mean grain size larger than 3?m showed discontinuous yielding. It suggests that appearance of the yield-drop phenomena can not be decided by the mean grain size. In order to consider effect of grain size distribution, the volume fraction of grains was summed from coarser grains, and the grain size when the summed volume fraction reached 70%, d70% was estimated from the grain size distribution. it was found that d70% of specimens which showed continuous yielding were larger than 8 ?m while the specimens which showed discontinuous yielding were smaller than 6 ?m, regardless of the lubrication condition in the ARB process. The result suggests that the appearance of the yield-drop phenomena depend on d70%.

2010-07-01

296

Tuning the electronic properties of boron nitride nanotube by mechanical uni-axial deformation: a DFT study  

Directory of Open Access Journals (Sweden)

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.

Ju Shin-Pon; Wang Yao-Chun; Lien Ting-Wei

2011-01-01

297

Tuning the electronic properties of boron nitride nanotube by mechanical uni-axial deformation: a DFT study.  

UK PubMed Central (United Kingdom)

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.

Ju SP; Wang YC; Lien TW

2011-01-01

298

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...

299

Deformation microstructures  

DEFF Research Database (Denmark)

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.

Hansen, N.; Huang, X.

2004-01-01

300

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.

1975-01-01

 
 
 
 
301

Deformation properties of even-even Os, Pt, Hg nuclei and spectroscopic properties of odd Re, Os, Ir, Pt, Au, Hg nuclei from self-consistent calculations  

International Nuclear Information System (INIS)

[en] Static properties of even-even Os, Pt, Hg nuclei have been obtained from HF + BCS calculations. Single-particle wave functions which come from these self-consistent calculations have been used to calculate some spectroscopic properties of odd Re, Os, Ir, Pt, Au and Hg nuclei, within the rotor + quasiparticle coupling model. Our calculations are able to give a good description of most of available experimental data. (orig.)

1981-07-20

302

Deformation properties of even-even Os, Pt, Hg nuclei and spectroscopic properties of odd Re, Os, Ir, Pt, Au, Hg nuclei from self-consistent calculations  

CERN Document Server

Static properties of even-even Os, Pt, Hg nuclei have been obtained from HF+BCS calculations. Single-particle wave functions which come from these self-consistent calculations have been used to calculate some spectroscopic properties of odd Re, Os, Ir, Pt, Au, and Hg nuclei, within the rotor-quasiparticle coupling model. The authors' calculations are able to give a good description of most of available experimental data. (12 refs).

Desthuilliers-Porquet, M G; Quentin, P; Sauvage-Letessier, J

1981-01-01

303

Accidental degeneracies in nonlinear quantum deformed systems  

Science.gov (United States)

We construct a multi-parameter nonlinear deformed algebra for quantum confined systems that includes many other deformed models as particular cases. We demonstrate that such systems exhibit the property of accidental pairwise energy level degeneracies. We also study, as a special case of our multi-parameter deformation formalism, the extension of the Tamm-Dancoff cutoff deformed oscillator and the occurrence of accidental pairwise degeneracy in the energy levels of the deformed system. As an application, we discuss the case of a trigonometric Rosen-Morse potential, which is successfully used in models for quantum confined systems, ranging from electrons in quantum dots to quarks in hadrons.

Aleixo, A. N. F.; Balantekin, A. B.

2011-09-01

304

Small-scale mechanical property characterization of ferrite formed during deformation of super-cooled austenite by nanoindentation  

International Nuclear Information System (INIS)

The mechanical properties of dynamically and statically transformed ferrites were analyzed using a nanoindentater-EBSD (Electron BackScattered Diffraction) correlation technique, which can distinguish indenting positions according to the grains in the specimen. The dilatometry and the band slope and contrast maps by EBSD were used to evaluate the volume fractions of two kinds of ferrite and pearlite. Fine ferrites induced by a dynamic transformation had higher nano-hardness than the statically transformed coarse ferrites. Transmission electron microscopy (TEM) showed the dynamic ferrites to have a higher dislocation density than the statically transformed ferrites.

2009-10-15

305

Study of deformation behavior, structure and mechanical properties of the AlSiMnFe alloy during ECAP-PBP.  

UK PubMed Central (United Kingdom)

The presented article deals with the effects of equal channel angular pressing (ECAP) with a newly adjusted die geometry on the microstructure and mechanical properties of the Al-Si-Mn-Fe alloy. This alloy was subjected to two modes of heat treatment followed by the ECAP process, which led to partial back pressure (ECAP-PBP). Ultra-fine grained (UFG) structure formed through ECAP-PBP process has been studied by methods of optical as well as electron microscopy. The obtained results indicate that quenched alloys, in comparison to slowly cooled alloys, do not contain large brittle particles which subsequently initiate a premature creation of cracks. It was shown that the mechanical properties of these alloys after such processing depend first and foremost on the selected type of heat treatment and on the number of performed passes. The maximum of ultimate tensile strength (417 MPa) was obtained for quenched alloy after 3 passes. On the other hand, maximum ductility was found in slowly cooled alloy after second pass. Further passes reduced strength due to the brittle behavior of excluded particles. One of the partial findings is that there is only a small dependency of the resulting size of grains on previously applied thermal processing. The minimum grain sizes were obtained after 3 passages, where their size ranged between 0.4 and 0.8 ?m. The application of quick cooling after heat processing due to the occurrence of finer precipitates in the matrix seems to produce better results.

Naizabekov AB; Andreyachshenko VA; Kocich R

2013-01-01

306

Size effects on the magnetic properties of Cu-Nb nanofilamentary wires processed by severe plastic deformation  

International Nuclear Information System (INIS)

We report on the influence of the microstructure on the AC and DC magnetic properties of Cu-3.5% Nb nanofilamentary wires. Samples obtained from a single Cu-3.5% Nb wire were subsequently submitted to different plastic strain levels via drawing so that their microstructure was altered. Noticeable differences are observed in their isothermal DC magnetization curves that present a double-peak structure. The first peak, which occurs at low magnetic fields, is attributed to superconductivity induced in the Cu matrix due to the proximity effect. It is argued that the second peak is related exclusively to niobium. The dependence of these two distinct peaks on the characteristic nanometre length scales of the samples, i.e. dimension of the Nb filaments and interfilamentary spacing, are discussed.

2006-01-01

307

Size effects on the magnetic properties of Cu-Nb nanofilamentary wires processed by severe plastic deformation  

Energy Technology Data Exchange (ETDEWEB)

We report on the influence of the microstructure on the AC and DC magnetic properties of Cu-3.5% Nb nanofilamentary wires. Samples obtained from a single Cu-3.5% Nb wire were subsequently submitted to different plastic strain levels via drawing so that their microstructure was altered. Noticeable differences are observed in their isothermal DC magnetization curves that present a double-peak structure. The first peak, which occurs at low magnetic fields, is attributed to superconductivity induced in the Cu matrix due to the proximity effect. It is argued that the second peak is related exclusively to niobium. The dependence of these two distinct peaks on the characteristic nanometre length scales of the samples, i.e. dimension of the Nb filaments and interfilamentary spacing, are discussed.

Sandim, M J R [Escola de Engenharia de Lorena, Universidade de Sao Paulo, Lorena 12600-970, SP (Brazil); Stamopoulos, D [Institute of Materials Science, NCSR ' Demokritos' , 153-10, Aghia Paraskevi, Athens (Greece); Sandim, H R Z [Escola de Engenharia de Lorena, Universidade de Sao Paulo, Lorena 12600-970, SP (Brazil); Ghivelder, L [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21945-970, RJ (Brazil); Thilly, L [Laboratoire de Metallurgie Physique, Universite de Poitiers, SP2M1, 86960 Futuroscope (France); Vidal, V [Laboratoire de Metallurgie Physique, Universite de Poitiers, SP2M1, 86960 Futuroscope (France); Lecouturier, F [Laboratoire National des Champs Magnetiques Pulses, CNRS-UPS-INSA, 31400 Toulouse (France); Raabe, D [Max-Planck-Institut fuer Eisenforschung, D-40237, Duesseldorf (Germany)

2006-12-15

308

Strains, stresses and elastic properties in polycrystallinemetallic thin films: in situ deformation combined with x-ray diffractionand simulation experiments  

Energy Technology Data Exchange (ETDEWEB)

X-ray diffraction is used in combination with tensiletesting for measuring elastic properties of metallic thin films. Sizeeffect, elastic anisotropy and grain morphologies are considered in allthese experiments and supported by different kind of numericalsimulations operating at different length scales. Such instrumentalstudies are time consuming even if synchrotron sources are used. Newexperiments are under progress for reducing acquisition data andimproving precision on strain measurements. After introducing briefly themain principles and results of our techniques, first promisingmeasurements on nanometric W/Cu multilayers using 2D CCD detectors andhigh monochromatic flux at the Advanced Light Source Berkeley (USA) onbeam line 11.3.1 are presented. In addition, simulation experiments foranalyzing elasticity in textured gold film are discussed.

Goudeau, P.; Faurie, D.; Girault, B.; Renault, P.-O.; Le Bourhis,E.; Villain, P.; Badawi, F.; Castelnau, O.; Brenner, R.; Bechade, J.-L.; Geandier, G.; Tamura, N.

2006-12-31

309

Asymmetric Rolling of Interstitial-Free Steel Using Differential Roll Diameters. Part I: Mechanical Properties and Deformation Textures  

Science.gov (United States)

IF steel sheets were processed by conventional symmetric and asymmetric rolling (ASR) at ambient temperature. The asymmetry was introduced in a geometric way using differential roll diameters with a number of different ratios. The material strength was measured by tensile testing and the microstructure was analyzed by optical and transmission electron microscopy as well as electron backscatter diffraction (EBSD) analysis. Texture was also successfully measured by EBSD using large surface areas. Finite element (FE) simulations were carried out for multiple passes to obtain the strain distribution after rolling. From the FE results, the velocity gradient along selected flow lines was extracted and the evolution of the texture was simulated using polycrystal plasticity modeling. The best mechanical properties were obtained after ASR using a roll diameter ratio of 2. The textures appeared to be tilted up to 12 deg around the transverse direction, which were simulated with the FE-combined polycrystal plasticity modeling in good agreement with measurements. The simulation work revealed that the shear component introduced by ASR was about the same magnitude as the normal component of the rolling strain tensor.

Orlov, Dmitry; Pougis, Arnaud; Lapovok, Rimma; Toth, Laszlo S.; Timokhina, Ilana B.; Hodgson, Peter D.; Haldar, Arunansu; Bhattacharjee, Debashish

2013-09-01

310

The effect of material properties and tooling design on deformation and fracture during equal channel angular extrusion  

Energy Technology Data Exchange (ETDEWEB)

The effects of material constitutive behavior, tooling design, and friction conditions on metal flow, stress fields, and the tendency for tensile fracture during equal channel angular extrusion (ECAE) were established using a finite element modeling (FEM) technique. Three different material behaviors, typical of those encountered during cold and hot working, were investigated; these comprised (1) string hardening, (2) rigid, perfectly plastic, and (3) flow softening types of behavior. The tooling geometries consisted of a so-called simple design with no moving channel members and a complex design with a sliding bottom floor. The FEM results indicated that the most uniform flow was obtained during ECAE of a strain-hardening material having a low strain-rate sensitivity in tolling with a sharp inner corner (front leg) radius. The ECAE of materials with other constitutive behaviors or in tooling with a radiused front leg showed some degree of flow nonuniformity, even away from the head and tail of the extrusion. Tooling design and material properties were also predicted to have an important influence on the tensile stresses and hence tensile damage developed during ECAE. The FEM results were validated using visioplasticity and fracture observations for AISI 4340 steel and a near-gamma titanium aluminide alloy.

Semiatin, S.L.; Delo, D.P.; Shell, E.B.

2000-05-11

311

First observation of excited states in 137Te and the extent of octupole instability in the lanthanides  

International Nuclear Information System (INIS)

Excited states in 137Te, populated in spontaneous fission of 248Cm, were studied by means of prompt-? spectroscopy, using the EUROGAM2 multidetector array. This is the first observation of excited states in 137Te. The yrast excitations of 137Te are due to the three valence neutrons, occupying the ?f7/2 and ?h9/2 orbitals, similarly as observed in its heavier N=85 isotones. Systematic comparison of excited levels in the N=85 isotones shows inconsistencies in spin and parity assignments in 139Xe and 141Ba nuclei. The new data for 137Te do not confirm earlier suggestions that octupole correlations increase in the N=85 isotones, close to the Z=50 closed shell. (c) 2000 The American Physical Society

2000-01-01

312

First observation of excited states in {sup 137}Te and the extent of octupole instability in the lanthanides  

Energy Technology Data Exchange (ETDEWEB)

Excited states in {sup 137}Te, populated in spontaneous fission of {sup 248}Cm, were studied by means of prompt-{gamma} spectroscopy, using the EUROGAM2 multidetector array. This is the first observation of excited states in {sup 137}Te. The yrast excitations of {sup 137}Te are due to the three valence neutrons, occupying the {nu}f{sub 7/2} and {nu}h{sub 9/2} orbitals, similarly as observed in its heavier N=85 isotones. Systematic comparison of excited levels in the N=85 isotones shows inconsistencies in spin and parity assignments in {sup 139}Xe and {sup 141}Ba nuclei. The new data for {sup 137}Te do not confirm earlier suggestions that octupole correlations increase in the N=85 isotones, close to the Z=50 closed shell. (c) 2000 The American Physical Society.

Urban, W. [Institute of Experimental Physics, Warsaw University, ul.Hoza 69, 00-681 Warszawa, (Poland); Korgul, A. [Institute of Experimental Physics, Warsaw University, ul.Hoza 69, 00-681 Warszawa, (Poland); Rzaca-Urban, T. [Institute of Experimental Physics, Warsaw University, ul.Hoza 69, 00-681 Warszawa, (Poland); Schulz, N. [Institut de Recherches Subatomiques UMR7500, CNRS-IN2P3 et Universite Louis Pasteur, 67037 Strasbourg, (France); Bentaleb, M. [Institut de Recherches Subatomiques UMR7500, CNRS-IN2P3 et Universite Louis Pasteur, 67037 Strasbourg, (France); Lubkiewicz, E. [Institut de Recherches Subatomiques UMR7500, CNRS-IN2P3 et Universite Louis Pasteur, 67037 Strasbourg, (France); Durell, J. L. [Schuster Laboratory, Department of Physics and Astronomy, University of Manchester, Manchester M13 9PL, (United Kingdom); Leddy, M. J. [Schuster Laboratory, Department of Physics and Astronomy, University of Manchester, Manchester M13 9PL, (United Kingdom); Jones, M. A. [Schuster Laboratory, Department of Physics and Astronomy, University of Manchester, Manchester M13 9PL, (United Kingdom); Phillips, W. R. [Schuster Laboratory, Department of Physics and Astronomy, University of Manchester, Manchester M13 9PL, (United Kingdom)] (and others)

2000-04-01

313

Shear deformation in granular materials  

Energy Technology Data Exchange (ETDEWEB)

An investigation into the properties of granular materials is undertaken via numerical simulation. These simulations highlight that frictional contact, a defining characteristic of dry granular materials, and interfacial debonding, an expected deformation mode in plastic bonded explosives, must be properly modeled. Frictional contact and debonding algorithms have been implemented into FLIP, a particle in cell code, and are described. Frictionless and frictional contact are simulated, with attention paid to energy and momentum conservation. Debonding is simulated, with attention paid to the interfacial debonding speed. A first step toward calculations of shear deformation in plastic bonded explosives is made. Simulations are performed on the scale of the grains where experimental data is difficult to obtain. Two characteristics of deformation are found, namely the intermittent binding of grains when rotation and translation are insufficient to accommodate deformation, and the role of the binder as a lubricant in force chains.

Bardenhagen, S.G.; Brackbill, J.U. [Los Alamos National Lab., NM (United States); Sulsky, D.L. [Univ. of New Mexico, Albuquerque, NM (United States)

1998-12-31

314

Extensional fault zone architecture and deformation band scaling properties in high-porosity sands: example from the Crotone basin (south Italy)  

Science.gov (United States)

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 < mean grain size < 800 µm) in forearc setting. The displacement of the studied fault 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.

Balsamo, Fabrizio; Storti, Fabrizio; Luca, Aldega

2013-04-01

315

Lie algebras Classification, Deformations and Rigidity  

CERN Multimedia

In the first section we recall some basic notions on Lie algebras. In a second time we study the algebraic variety of complex $n$-dimensional Lie algebras. We present different notions of deformations : Gerstenhaber deformations, pertubations, valued deformations and we use these tools to study some properties of this variety. Finaly we introduce the concept of rigidity and we present some results on the class of rigid Lie algebras.

Goze, M

2006-01-01

316

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)

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)

Regle, H.

1994-12-31

317

Distributed actuator deformable mirror  

CERN Multimedia

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.

Bonora, Stefano

2010-01-01

318

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

Energy Technology Data Exchange (ETDEWEB)

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)

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

319

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.

2000-10-09

320

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)

2000-01-01

 
 
 
 
321

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

Science.gov (United States)

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.

Smirnova, N. A.; Pietralla, N.; Mizusaki, T.; Van Isacker, P.

2000-10-01

322

G-factors in 210 Rn and octupole coupling of core excited states in 210Rn, 211Rn and 212Rn  

International Nuclear Information System (INIS)

The g-factors of isomeric states in 210Rn have been measured using the TDPAD technique. Semi-empirical shell model calculations, with explicit inclusion of the couplings to the 3- octupole vibration, are carried out for the core excited states in 210Rn and 211Rn, 212Rn. The resulting mixed multi-particle configurations are used to explain simultaneously the g-factors and enhanced E3 transitions which connect several pairs of these states

1985-01-01

323

Emittance growth scaling laws for crossing systematic space-charge driven sixth-order resonances and random octupole driven fourth-order resonances in FFAGs  

International Nuclear Information System (INIS)

[en] Scaling laws of the emittance growth factor (EGF) for a beam crossing the 6th order systematic space-charge resonances and the random 4th order resonance driven by octupoles are obtained by numerical multi-particle simulations. These scaling laws can be important in setting the minimum acceleration rate, and the maximum tolerable resonance strength for the design of the non-scaling fixed-field alternating gradient (FFAG) accelerators

2007-01-01

324

Deformed chiral nucleons  

Energy Technology Data Exchange (ETDEWEB)

We compute properties of the nucleon in a hybrid chiral model based on the linear {sigma}-model with quark degrees of freedom treated explicity. In contrast to previous calculations, we do not use the hedgehog ansatz. Instead we solve self-consistently for a state with well defined spin and isospin projections. We allow this state to be deformed and find that, although d- and g-state admixtures in the predominantly s-state single quark wave functions are not large, they have profound effects on many nucleon properties including magnetic moments and g{sub A}. Our best fit parameters provide excellent agreement with experiment but are much different from those determined in hedgehog calculations. (orig.).

Price, C.E.; Shepard, J.R. (Colorado Univ., Boulder (USA). Dept. of Physics)

1991-04-18

325

Deformed chiral nucleons  

International Nuclear Information System (INIS)

[en] We compute properties of the nucleon in a hybrid chiral model based on the linear ?-model with quark degrees of freedom treated explicity. In contrast to previous calculations, we do not use the hedgehog ansatz. Instead we solve self-consistently for a state with well defined spin and isospin projections. We allow this state to be deformed and find that, although d- and g-state admixtures in the predominantly s-state single quark wave functions are not large, they have profound effects on many nucleon properties including magnetic moments and gA. Our best fit parameters provide excellent agreement with experiment but are much different from those determined in hedgehog calculations. (orig.)

1991-04-18

326

Quantum interference in deformed carbon nanotube waveguides  

CERN Document Server

Quantum interference (QI) in two types of deformed carbon nanotubes (CNTs), i.e., axially stretched and AFM tip-deformed CNTs, has been investigated by the pi-electron only and four-orbital tight-binding (TB) method. It is found that the rapid conductance oscillation (RCO) period is very sensitive to the applied strains, and decreases in an inverse proportion to the deformation degree, which could be used as a powerful experimental tool to detect precisely the deformation degree of the deformed CNTs. Also, the sigma-pi coupling effect is found to be negligible under axially stretched strain, while it works on the transport properties of the tip-deformed CNTs.

Fa, W; Fa, Wei; Dong, Jinming

2004-01-01

327

The 2.57 MeV 19/2- two-phonon octupole state in 147Gd  

International Nuclear Information System (INIS)

The half life of the (?fsub(7/2) x 3- x 3-)sub(19/2)- two-phonon octupole state at 2.572 MeV in 147GD was measured as Tsub(1/2) = 0.37 (8) ns, which gives a transition strength of 52(15) W.U. for the 1525 keV E3 transition to the 0.997 MeV (?fsub(7/2) x 3-)sub(13/2)+ one phonon excitation. The ?isub(13/2) admixture in the 13/2+ one-phonon state, as well as the dominant ?hsub(11/2)d-1sub(5/2) component of the 146Gd 3- state give rise to large anharmonicities for the two-phonon excitation. An estimate of the energy shifts based on empirical coupling matrix elements gives 2.66 MeV excitation for the 19/2- two-phonon state, in good agreement with the observed energy of that state. (orig./HSI)

1981-07-20

328

Additive/multiplicative free subordination property and limiting eigenvectors of spiked additive deformations of Wigner matrices and spiked sample covariance matrices  

CERN Document Server

When some eigenvalues of a spiked multiplicative resp. additive deformation model of a Hermitian Wigner matrix resp. a sample covariance matrix separate from the bulk, we study how the corresponding eigenvectors project onto those of the perturbation. We point out that the inverse of the subordination function relative to the free additive resp. multiplicative convolution plays an important part in the asymptotic behavior.

Capitaine, Mireille

2011-01-01

329

Deformations of crystal frameworks  

CERN Document Server

We apply our deformation theory of periodic bar-and-joint frameworks to tetrahedral crystal structures. The deformation space is investigated in detail for frameworks modelled on quartz, cristobalite and tridymite.

Borcea, Ciprian S

2011-01-01

330

Deformation at Crystallite Interfaces.  

Science.gov (United States)

Deformation at grain boundaries is observed and a framework for bound specific constitutive laws based upon geometric considerations of slip transfer is developed. Orientation images of a pseudo-internal surface during interrupted channel die deformations...

D. P. Field A. W. Mortensen M. M. Nowell G. H. Campbell

2001-01-01

331

Interrelation between the isoscalar octupole phonon and the proton-neutron mixed-symmetry quadrupole phonon in near-spherical nuclei[21.10.Re; 21.60.Ev; 21.60.Fw; Quadrupole-octupole multiphonon excitations; Negative-parity states; Mixed-symmetry states; Interacting boson model sdf-IBM-2; Transition strength  

Energy Technology Data Exchange (ETDEWEB)

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{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 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.

Smirnova, Nadya A. E-mail: Nadya.Smirnova@fys.kuleuven.ac.be; Pietralla, Norbert; Mizusaki, Takahiro; Van Isacker, Piet

2000-10-09

332

Thermodynamic geometry of deformed bosons and fermions  

International Nuclear Information System (INIS)

We construct the thermodynamic geometry of an ideal q-deformed boson and fermion gas. We investigate some thermodynamic properties such as the stability and statistical interaction. It will be shown that the statistical interaction of q-deformed boson gas is attractive, while it is repulsive for the q-deformed fermion one. Also, we will consider the singular point of the thermodynamic curvature to obtain some new results about the condensation of q-deformed bosons and show that there exists a finite critical phase transition temperature even in low dimensions. It is shown that the thermodynamic curvature of q-deformed boson and fermion quantum gases diverges as a power-law function with respect to temperature at zero-temperature limit. (paper)

2011-11-25

333

Effect of Physical Properties of Al-Si Electrode Films on the Deformation Behaviors and the Strength of Thick Al Wire Bonds during Thermal Cycle Test  

Science.gov (United States)

The deformation behaviors of Al-Si films and the strength change of Al wire bonds on Al-Si films during heating and cooling cycles have been investigated as a function of substrate temperature of the sputtering process; the purpose was to clarify reliability of both Al wire bonds and Al-Si films for use in insulated gate bipolar transistor (IGBT) modules. The extent of deformation in Al-Si films sputtered at 593 K during heating and cooling cycles was the smallest among films sputtered at room temperature (RT), 473 K, and 593 K. The strength of Al wire bonds on Al-Si films sputtered at the three temperatures was the highest for Al-Si films sputtered at 593 K. The reliability of Al wire bonds on Al-Si films formed at 593 K was about two times higher than the bond reliability on Al-Si films formed at RT and 473 K.

Shimizu, Yousuke; Tomota, Yo; Onuki, Jin; Khoo, Khyou Pin; Kurosu, Toshiki

2009-06-01

334

Dipole, quadrupole, and octupole terms in the long-range hyperfine frequency shift for hydrogen in the presence of inert gases  

International Nuclear Information System (INIS)

The R-6, R-8, and R-10 terms in the long-range expansion for the hyperfine frequency shift are calculated for hydrogen in the presence of He, Ne, Ar, Kr, and Xe. The R-6 terms are based on the dipole oscillator strength sums. For helium, the R-8 and R-10 terms are based on quadrupole and octupole oscillator strength sums. For the heavier inert gases, the results for the R-8 and R-10 terms are obtained from the sum rules and the static polarizabilities. Upper bounds are also determined for the R-8 and R-10 terms.

1987-01-01

335

Determination of the B(E3,0$^{+}$->3$^{-}$) strength in the octupole correlated nucleus 144Ba using Coulomb excitation  

CERN Document Server

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:

336

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.

337

Tangent lifting of deformations in mixed characteristic  

CERN Document Server

This article presents a new approach to the unobstructedness result for deformations of Calabi-Yau varieties by introducing the tangent lifting property for a functor on artinian local algebras. The verification that the deformation functor of a Calabi-Yau variety in characteristic 0 fulfills the tangent lifting property uses, just as the verification of the $T^1$-lifting property, the degeneration of the Hodge to de Rham spectral sequence. Our main use of our methods is however to the mixed characteristic case. In that case to be able to verify the conditions needed one needs an extension of the criterion introducing divided powers.

Ekedahl, T; Ekedahl, Torsten; Shepherd-Barron, Nick I.

2003-01-01

338

Extended VMI model for asymmetric deformed nuclei  

International Nuclear Information System (INIS)

The nature of the ground and the ? band is studied in the asymmetric rotator model for larger asymmetric deformations ? and higher angular momenta. Properties of the ? band are found which may make it possible to search experimentally for static ? deformations. Sum rules for quadrupole moments and energies are derived. For the description of higher angular momenta the softness of the nucleus is included by an extension of the VMI model to asymmetric deformations. Energies, quadrupole moments and E2 transitions are given for the Os region and compared with the available data. (orig.)

1976-01-01

339

Deformation of C15 Laves phase alloys  

Energy Technology Data Exchange (ETDEWEB)

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.

Chu, F.; Pope, D.P.

1995-12-31

340

IBA in deformed nuclei  

Energy Technology Data Exchange (ETDEWEB)

The structure and characteristic properties and predictions of the IBA in deformed nuclei are reviewed, and compared with experiment, in particular for /sup 168/Er. Overall, excellent agreement, with a minimum of free parameters (in effect, two, neglecting scale factors on energy differences), was obtained. A particularly surprising, and unavoidable, prediction is that of strong ..beta.. ..-->.. ..gamma.. transitions, a feature characteristically absent in the geometrical model, but manifest empirically. Some discrepancies were also noted, principally for the K=4 excitation, and the detailed magnitudes of some specific B(E2) values. Considerable attention is paid to analyzing the structure of the IBA states and their relation to geometric models. The bandmixing formalism was studied to interpret both the aforementioned discrepancies and the origin of the ..beta.. ..-->.. ..gamma.. transitions. The IBA states, extremely complex in the usual SU(5) basis, are transformed to the SU(3) basis, as is the interaction Hamiltonian. The IBA wave functions appear with much simplified structure in this way as does the structure of the associated B(E2) values. The nature of the symmetry breaking of SU(3) for actual deformed nuclei is seen to be predominantly ..delta..K=0 mixing. A modified, and more consistent, formalism for the IBA-1 is introduced which is simpler, has fewer free parameters (in effect, one, neglecting scale factors on energy differences), is in at least as good agreement with experiment as the earlier formalism, contains a special case of the 0(6) limit which corresponds to that known empirically, and appears to have a close relationship to the IBA-2. The new formalism facilitates the construction of contour plots of various observables (e.g., energy or B(E2) ratios) as functions of N and chi/sub Q/ which allow the parameter-free discussion of qualitative trajectories or systematics.

Casten, R.F.; Warner, D.D.

1982-01-01

 
 
 
 
341

Effects of nickel content and deformation-induced martensitic transformation on the fatigue properties of type 304 stainless steel sheets at room and cryogenic temperatures  

International Nuclear Information System (INIS)

Effects of Ni content(8.3?12 wt%) and deformation-induced martensitic transformation on the bending and zero to tension fatigue behavior of type 304 stainless steel used for the membrane of LNG storage tank at room and cryogenic temperature were investigated. By lowering the Ni content, the bending fatigue life at room temperature was decreased at the high level of total strain amplitude. It would be attributed to the crack initiation at ?/?' interface and the low ductility with the increase of ?' contents. However, at the low level of total strain amplitude, lowering the Ni content increased the bending fatigue life. It was due to the suppression of crack propagation by the ?'-martensite transformation around crack tip and the increase of tensile strength. At cryogenic temperature, lowering the Ni content showed beneficial effect on the bending fatigue life due to the increase of slip deformation resistance. In the zero to tension fatigue test, lowering the Ni content showed better fatigue characteristics regardless of the temperature variation. In this case, the high tensile strength with the ?'-martensite transformation mostly affects material's fatigue life

2001-01-01

342

Effects of nickel content and deformation-induced martensitic transformation on the fatigue properties of type 304 stainless steel sheets at room and cryogenic temperatures  

Energy Technology Data Exchange (ETDEWEB)

Effects of Ni content(8.3{approx}12 wt%) and deformation-induced martensitic transformation on the bending and zero to tension fatigue behavior of type 304 stainless steel used for the membrane of LNG storage tank at room and cryogenic temperature were investigated. By lowering the Ni content, the bending fatigue life at room temperature was decreased at the high level of total strain amplitude. It would be attributed to the crack initiation at {gamma}/{alpha}{sup '} interface and the low ductility with the increase of {alpha}{sup '} contents. However, at the low level of total strain amplitude, lowering the Ni content increased the bending fatigue life. It was due to the suppression of crack propagation by the {alpha}{sup '}-martensite transformation around crack tip and the increase of tensile strength. At cryogenic temperature, lowering the Ni content showed beneficial effect on the bending fatigue life due to the increase of slip deformation resistance. In the zero to tension fatigue test, lowering the Ni content showed better fatigue characteristics regardless of the temperature variation. In this case, the high tensile strength with the {alpha}{sup '}-martensite transformation mostly affects material's fatigue life.

Ryoo, Do Yeal; Lee, Soo Chan; Lee, Yong Deuk [Pohang Iron and Steel Co., Ltd. Technical Research Laboratories, Pohang (Korea, Republic of); Kang, Jung Yoon [Busan National Univ., Busan (Korea, Republic of)

2001-12-01

343

Geometry and dynamics of a tidally deformed black hole  

International Nuclear Information System (INIS)

The metric of a nonrotating black hole deformed by a tidal interaction is calculated and expressed as an expansion in the strength of the tidal coupling. The expansion parameter is the inverse length scale R-1, where R is the radius of curvature of the external spacetime in which the black hole moves. The expansion begins at order R-2, and it is carried out through order R-4. The metric is parametrized by a number of tidal multipole moments, which specify the black hole's tidal environment. The tidal moments are freely-specifiable functions of time that are related to the Weyl tensor of the external spacetime. At order R-2 the metric involves the tidal quadrupole moments Eab and Bab. At order R-3 it involves the time derivative of the quadrupole moments and the tidal octupole moments Eabc and Babc. At order R-4 the metric involves the second time derivative of the quadrupole moments, the first time derivative of the octupole moments, the tidal hexadecapole moments Eabcd and Babcd, and bilinear combinations of the quadrupole moments. The metric is presented in a light-cone coordinate system that possesses a clear geometrical meaning: The advanced-time coordinate v is constant on past light cones that converge toward the black hole; the angles ? and ? are constant on the null generators of each light cone; and the radial coordinate r is an affine parameter on each generator, which decreases as the light cones converge toward the black hole. The coordinates are well-behaved on the black-hole horizon, and they are adjusted so that the coordinate description of the horizon is the same as in the Schwarzschild geometry: r=2M+O(R-5). At the order of accuracy maintained in this work, the horizon is a stationary null hypersurface foliated by apparent horizons; it is an isolated horizon in the sense of Ashtekar and Krishnan. As an application of our results we examine the induced geometry and dynamics of the horizon, and calculate the rate at which the black-hole surface area increases as a result of the tidal interaction.

2010-01-15

344

Magnetic octupole order in Ce{sub 0.7}La{sub 0.3}B{sub 6}: A polarized neutron diffraction study  

Energy Technology Data Exchange (ETDEWEB)

Recently, in phase IV of Ce{sub x}La{sub 1-x}B{sub 6}, 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 Ce{sub 0.7}La{sub 0.3}B{sub 6}. 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 Ce{sub x}La{sub 1-x}B{sub 6}.

Kuwahara, K., E-mail: kuwa@mx.ibaraki.ac.j [Institute of Applied Beam Science, Ibaraki University, Ibaraki 310-8512 (Japan); Iwasa, K. [Department of Physics, Tohoku University, Sendai 980-8578 (Japan); Kohgi, M. [Department of Physics, Tokyo Metropolitan University, Tokyo 192-0397 (Japan); Aso, N. [Neutron Science Laboratory, Institute for Solid State Physics, University of Tokyo, Ibaraki 319-1106 (Japan); Sera, M.; Iga, F. [Department of Quantum Matter, ADSM, Hiroshima University, Hiroshima 739-8530 (Japan); Matsuura, M.; Hirota, K. [Department of Earth and Space Science, Osaka University, Osaka 560-0043 (Japan)

2009-09-01

345

Extended deformation functors, 1  

CERN Document Server

We introduce a precise notion, in terms of few Schlessinger's type conditions, of extended deformation functors which is compatible with most of recent ideas in the Derived Deformation Theory (DDT) program and with geometric examples. With this notion we develop the (extended) analogue of Schlessinger and obstruction theories. The inverse mapping theorem holds for natural transformations of extended deformation functors and all such functors with finite dimensional tangent space are prorepresentable in the homotopy category.

Manetti, M

1999-01-01

346

Giants On Deformed Backgrounds  

CERN Multimedia

We study giant graviton probes in the framework of the three--parameter deformation of the AdS_5 x S^5 background. We examine both the case when the brane expands in the deformed part of the geometry and the case when it blows up into AdS. Performing a detailed analysis of small fluctuations around the giants, the configurations turn out to be stable. Our results hold even for the supersymmetric Lunin-Maldacena deformation.

Pirrone, M

2006-01-01

347

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.

1988-01-01

348

Deformations of monoidal functors  

CERN Multimedia

We point out that for Yetter's deformational Hochschild complex of a monoidal functor between abelian monoidal categories the Gerstenhaber-Voronov type operations can be defined making it a strong homotopy Gerstenhaber algebra. This encodes deformation theory of monoidal functors in an analogical way as deformation theory of associative algebras is described by the strong homotopy Gerstenhaber algebra structure on the corresponding Hochschild cochains. We describe a quasi-classical limit of deformations of a symmetric monoidal functor in terms of Poisson type structure.

Maszczyk, Tomasz

2011-01-01

349

Deformation At Crystallite Interfaces  

Energy Technology Data Exchange (ETDEWEB)

Deformation at grain boundaries is observed and a framework for boundary specific constitutive laws based upon geometric considerations of slip transfer is developed. Orientation images of a pseudo-internal surface during interrupted channel die deformations of a Cu bi-crystal show the heterogeneity of lattice rotation near the grain boundary. The experiments demonstrate that a region near the boundary is strongly influenced by neighboring grain deformation and lend support to the development of deformation models that include the effects of non-local slip system interaction.

Field, D P; Mortensen, A W; Nowell, M M; Campbell, G H

2001-10-05

350

Seismic properties and deformation record of the shallow upper mantle beneath SE Iberia: insights from mantle xenoliths in Neogene alkaline basalts  

Science.gov (United States)

The volcanic activity in the SE Iberian Volcanic Province is the surface expression of magmatism in a complex geodynamic setting during the Cenozoic development of a Mediterranean-type back-arc basin in the Alboran realm. The late stage of this geodynamical evolution was characterized by Neogene alkaline basalt volcanism erupted at 2-3 Ma in the Tallante and Los Perez (Murcia) volcanic centers. This volcanism entrained numerous mantle xenoliths that provide a snapshot of the structure and composition of the lithospheric mantle beneath this region. Xenoliths are spinel (± plagioclase ± amphibole) lherzolite, and minor harzburgite and wehrlite showing porphyroclastic to fine- to medium-grained granoblastic textures. Mantle xenoliths display a marked olivine crystal preferred orientation (CPO) that is similar in the two investigated volcanic centers. The dominant olivine CPO is [100]-fiber pattern characterized by a strong alignment of olivine [100] axes near or parallel to the peridotite lineation and a girdle distribution of [010] axes with a maximum normal to the peridotite foliation. This CPO is consistent with dominant activation of the high temperature [100]{0kl} slip systems of olivine and suggests simple shear or combinations of simple shear and pure shear with a transtensional component were the dominant deformation regimes. These olivine CPO contrast with those of Ronda peridotite -sampling the lithospheric mantle of the Alboran domain at 23 Ma- which are consistent with a transpressional deformation regime, indicating a temporal evolution of the deformation regime to transpressive to a transtensive in the Miocene. The seismic anisotropy calculated from xenolith's CPO and modal compositions is characterized by fast propagation of P-waves and polarization of fast S-waves parallel to the lineation. Highest delay times are observed for S-waves propagating within the foliation, but at high angle to the lineation, whereas S-waves propagating along the lineation sample an apparent isotropy direction. Based on these data, we interpret the recent SKS splitting measurements in the western Mediterranean as indicating dominant belt-parallel flow in the mantle beneath the Betic Cordillera.

Konc, Z.; Garrido, C.; Tommasi, A.; Padrón-Navarta, J.; Hidas, K.; Szabo, C.

2011-12-01

351

q-Deformed Schroedinger equation  

International Nuclear Information System (INIS)

In a q-deformed quantum mechanics the commutation relations between the generators of the SUq(2) algebra, L-vector and the position vector, r, are well defined and it is natural to take this vectors as the basic quantities from which all the others must be built. To build a q-deformed Schroedinger Hamiltonian a realization of p-vector entering the kinetic energy term was necessary to find. p-Vector can be written as a sum of two terms which are parallel and perpendicular to r-vector, respectively. We first obtained the general commutation relations involving the q-angular momentum and some quantities having definite transformation properties with respect to SUq(2) algebra. We then give a realization of the position vector and of the q-angular momentum, L, in terms of polar coordinates. Then, we obtained the realization of the linear momentum p made of a part perpendicular to r-vector, satisfying similar commutation relations to those corresponding to r-vector, and of a part parallel to r-vector supposed to have the simplest form, i.e., that coming from the ordinary partial derivative with respect to r-vector. We calculated the Eigenfunctions of the q-angular momentum, written like a series expansion in terms of cos?. The result is a generalization of two hypergeometric functions which can be related to the q-deformed spherical functions Ylm. Some properties and relations satisfied by the Eigenfunctions are also listed. In the last section the q-deformed Schroedinger equation with scalar potential is given. Its solutions for Coulomb and three dimensional oscillator potential are briefly discussed

1997-01-01

352

Influence of monotonously or incrementally applied deformation of limited amount on the remaining material properties of austenitic steel (1.4550)  

International Nuclear Information System (INIS)

Sample experiments were carried out on the most usual Austenitic steel X6 CrNiNb 18 10 in German nuclear powerstations to examine the ratcheting deformation of Austenitic components. For three tension/compression alternating load experiments with alternating temperature, an incremental increase in the strain was found, depending on the width of swing of the stress or strain. This process, described as material ratcheting, is based on the different flow behaviour (elastic limit, tangent module) of the material at high and low temperature. In evaluating the results of the experiment, using the real stress situation of inductive bending in a volume compensation pipe of a PWR plant, it was found that there is a greater safety factor for the components concerned compared to the occurrence of relevant amounts of accumulated incremental increases in strain. (orig./DG)

1992-01-01

353

Effect of precipitates on long-term creep deformation properties of P92 and P122 type advanced ferritic steels for USC power plants  

Energy Technology Data Exchange (ETDEWEB)

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 M{sub 2}N 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 the fine precipitates such as Cr{sub 2}(C, N) caused by the compositions change like Cr supply to MX carbonitride is more essential.

Yoshizawa, M., E-mail: yoshizaw-mtr@sumitomometals.co.jp [Corporate Research and Development Laboratories, Sumitomo Metal Industries, Ltd., 1-8 Fuso-cho, Amagasaki, Hyogo 660-0891 (Japan); Igarashi, M.; Moriguchi, K. [Corporate Research and Development Laboratories, Sumitomo Metal Industries, Ltd., 1-8 Fuso-cho, Amagasaki, Hyogo 660-0891 (Japan); Iseda, A. [Tubular Products Technology Department, Sumitomo Metal Industries, Ltd., 1-8-11 Harumi, Chuo-ku, Tokyo 104-6111 (Japan); Armaki, Hassan Ghassemi; Maruyama, K. [Graduate School of Environmental Studies, Tohoku University, 6-6-02 Aobayama, Sendai 980-8579 (Japan)

2009-06-15

354

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 the fine precipitates such as Cr2(C, N) caused by the compositions change like Cr supply to MX carbonitride is more essential.

2009-06-15

355

An Algebraic q-Deformed Form for Shape-Invariant Systems  

CERN Multimedia

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.

Aleixo, A N F; Ribeiro, M A C

2003-01-01

356

Modeling tire deformation for power loss calculations  

Energy Technology Data Exchange (ETDEWEB)

A combined thermo-mechanical model for calculating tire power loss has been developed at GMR. This paper presents the techniques for developing the realistic finite element models needed in both the thermal and deformation portions of the combined model. It also describes the techniques used in calculating deformed tire shapes. First, procedures are outlined for automatically generating a finite element discretization of a tire. Then, this discretization, together with information about the properties of tire materials, is used to develop a finite element model of the tire. This model is used in MSC NASTRAN to calculate compliances, i.e., the response of the tire to inflation and to unit loads applied at points on the tire surface. These compliances are then used in an algorithm which calculates the deformed shape of a tire loaded against the pavement surface. Sample results are presented to show the agreement between calculated and measured tire deformation.

Whicker, D.; Rohde, S.M.

1981-01-01

357

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)

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.

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

358

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)

[en] 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

2011-01-01

359

Understanding nuclear quadrupole deformations  

International Nuclear Information System (INIS)

A simple ansatz that ''Nuclei, not too near closed shells, are as deformed as they can be within a single major shell'' appears to quantitatively reproduce the variations of the quadrupole moments and hence the deformations of nuclei. 6 refs., 3 figs

1989-01-01

360

Strengthening of HSLA steels by cool deformation  

International Nuclear Information System (INIS)

[en] 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 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.

2010-06-25

 
 
 
 
361

Strengthening of HSLA steels by cool deformation  

Energy Technology Data Exchange (ETDEWEB)

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 temperature properties. Even low amounts of copper (e.g. {approx}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.

Fatehi, A., E-mail: arya.fatehi@gmail.com [Department of Mining, Metals and Materials Engineering, McGill University, 3610 University Street, Montreal, QC, H3A 2B2 (Canada); Calvo, J.; Elwazri, A.M.; Yue, S. [Department of Mining, Metals and Materials Engineering, McGill University, 3610 University Street, Montreal, QC, H3A 2B2 (Canada)

2010-06-25

362

Deformation twinning of titanium ?-alloys of transition class  

International Nuclear Information System (INIS)

The structure of deformed ?-titanium transition type alloys is investigated, and the model of deformation twinning is developed permitting the explanation of mechanical properties obtained in the alloys: low yield strength, high hardening coefficient and high ductility. It is shown that a drastic decrease of plasticity and yield strength increasing resulted from aging of ?-titanium transition alloys after cold plastic deformation are due to the formation of the skeleton of ?-phase plates-packets in position of twinning skeleton

2006-01-01

363

Behavior of shell effects with the excitation energy in atomic nuclei  

UK PubMed Central (United Kingdom)

We study the behavior of shell effects, like pairing correlations and shape deformations, with the excitation energy in atomic nuclei. The analysis is carried out with the finite temperature Hartree-Fock-Bogoliubov method and a finite range density dependent force. For the first time, properties associated with the octupole and hexadecupole deformation and with the superdeformation as a function of the excitation energy are studied. Calculations for the well quadrupole deformed 164Er and 162Dy, superdeformed 152Dy, octupole deformed 224Ra, and spherical 118Sn nuclei are shown. We find, in particular, the level density of superdeformed states to be 4 orders of magnitude smaller than for normal deformed ones.

Egido JL; Robledo LM; Martin V V

2000-07-01

364

Eigenvalues of Deformed Random Matrices  

CERN Multimedia

We present a novel approach to study eigenvalues of deformed random matrices. This approach applies to many deformed Gaussian matrix models; two such models are studied in detail: the deformed GOE and the spiked population model.

Peng, Minyu

2012-01-01

365

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)

Full Text Available 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 presença 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 coer (more) ente ?'. 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 presence 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 (more) 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.

Souza, G. R. X.; Gabriel, S. B.; Ribeiro, A. F.; Almeida, L. H. de

2013-01-01

366

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

1995-01-01

367

Integrable Systems and Isomonodromy Deformations  

CERN Multimedia

We analyze in detail three classes of isomondromy deformation problems associated with integrable systems. The first two are related to the scaling invariance of the $n\\times n$ AKNS hierarchies and the Gel'fand-Dikii hierarchies. The third arises in string theory as the representation of the Heisenberg group by $[(L^{k/n})_+,L]=I$ where $L$ is an $n^{th}$ order scalar differential operator. The monodromy data is constructed in each case; the inverse monodromy problem is solved as a Riemann-Hilbert problem; and a simple proof of the Painlevé property is given for the general case

Beals, R; Beals, Richard

1998-01-01

368

Calcaneo-valgus deformity.  

UK PubMed Central (United Kingdom)

A discussion of the essential deformity in calcaneo-valgus feet develops a theme originally put forward in 1961 on the relapsed club foot (Evans 1961). Whereas in the normal foot the medial and lateral columns are about equal in length, in talipes equino-varus the lateral column is longer and in calcaneo-valgus shorter than the medial column. The suggestion is that in the treatment of both deformities the length of the columns be made equal. A method is described of treating calcaneo-valgus deformity by inserting cortical bone grafts taken from the tibia to elongate the anterior end of the calcaneus.

Evans D

1975-08-01

369

Giants on deformed backgrounds  

Energy Technology Data Exchange (ETDEWEB)

We study giant graviton probes in the framework of the three-parameter deformation of the AdS{sub 5} x S{sup 5} background. We examine both the case when the brane expands in the deformed S-tilde{sup 5} part of the geometry and the case when it blows up into AdS{sub 5}. Performing a detailed analysis of small fluctuations around the giants, the configurations turn out to be stable. Our results hold even for the supersymmetric Lunin-Maldacena deformation.

Pirrone, Marco [Dipartimento di Fisica, Universita di Milano-Bicocca and INFN, Sezione di Milano-Bicocca, Piazza della Scienza 3, I-20126 Milan (Italy)

2006-12-15

370

Giants on deformed backgrounds  

International Nuclear Information System (INIS)

We study giant graviton probes in the framework of the three-parameter deformation of the AdS5 x S5 background. We examine both the case when the brane expands in the deformed S-tilde5 part of the geometry and the case when it blows up into AdS5. Performing a detailed analysis of small fluctuations around the giants, the configurations turn out to be stable. Our results hold even for the supersymmetric Lunin-Maldacena deformation.

2006-01-01

371

Biophysical approach. Theoretical models of deformability in blood flow.  

UK PubMed Central (United Kingdom)

The physical properties of red blood cell membranes pertinent to deformability are the membrane shear modulus, the bending stiffness and shear viscosity. In filtration tests the rate of deformation is sufficiently high that the viscous behaviour of the membrane and of cell contents predominate.

Skalak R

1981-01-01

372

On the existence of a magnetic octupole moment in mesic atoms in 1S1/2 and 2P1/2 states  

International Nuclear Information System (INIS)

[en] It is shown that mesic atoms, their nucleus spin J?1, still possess octupole magnetic moment ? even in S1/2 and P172 states. The effect of ??0 existence in S1/2, P1/2 states is conditioned by the same reasons which cause the existence of electrical quadrupole moment in mesic atoms with J?0 in the same states: hyperfine interaction between the nucleus and negative ?-muon adds D3/2, D5/2... states to S1/2 term and P3/2, F5/2 etc. states allowed by the law of conservation of complete moment of F mesic atom and its projection M and possessing the same parity as the initial state-to P172 term

1987-07-04

373

Dipole, quadrupole, and octupole terms in the long-range hyperfine frequency shift for hydrogen in the presence of inert gases  

Energy Technology Data Exchange (ETDEWEB)

The R/sup -6/, R/sup -8/, and R/sup -10/ terms in the long-range expansion for the hyperfine frequency shift are calculated for hydrogen in the presence of He, Ne, Ar, Kr, and Xe. The R/sup -6/ terms are based on the dipole oscillator strength sums. For helium, the R/sup -8/ and R/sup -10/ terms are based on quadrupole and octupole oscillator strength sums. For the heavier inert gases, the results for the R/sup -8/ and R/sup -10/ terms are obtained from the sum rules and the static polarizabilities. Upper bounds are also determined for the R/sup -8/ and R/sup -10/ terms.

Greenwood, W.G.; Tang, K.T.

1987-03-15

374

Anharmonicities of ?-vibrations in deformed nuclei  

International Nuclear Information System (INIS)

The anharmonicities of ?-vibrations are studied within the multiphonon method in different even-even deformed nuclei where the first K?=2+ vibrational state appears well below the energy gap: 130Ce, 162-164Dy, 164-168Er, 186Os. The anharmonicities previously obtained in 168Er appear to be a general property of these nuclei. (orig.).

1988-01-01

375

Gardner's deformations of the Boussinesq equations  

CERN Document Server

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.

Karasu, A; Karasu, Atalay; Kiselev, Arthemy V.

2006-01-01

376

Marginal Polytope of a Deformed Exponential Family  

CERN Multimedia

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.

Pistone, Giovanni

2011-01-01

377

Interactive Axial Deformations  

UK PubMed Central (United Kingdom)

: This paper presents an interactive deformation technique. The entity employedfor defining the deformation of an object is a 3D axis as well as some associated parameters.The technique allows an easy specification and control of deformations that can be definedwith that entity such as bending, twisting and scaling.Contrary to existing techniques, the method developed is independent of both the geometricmodel of the object to be deformed and the creation technique used to define theobject.Moreover, it can easily be integrated into traditional interactive modeling systems.Key-words: CR Categories and Subject Descriptors: I.3.5 [Computer Graphics]:ComputationalGeometry and Object Modeling - Curve, surface, solid, and object representation; Geometricalgorithms, languages, and systems; Hierarchy and geometric transformations; I.3.6[Computer Graphics]: Methodology and Techniques - Interaction techniques.(R'esum'e : tsvp)Email : fFrancis.Lazarus,Sabine.Coquillart,Pierre.Jan...

Pierre Jancene; Francis Lazarus; Sabine Coquillart; Programme Robotique; Projet Syntim

378

Hyperbolicity of general deformations  

CERN Document Server

We present two methods of constructing low degree Kobayashi hyperbolic hypersurfaces in the projective space: the projection method and the deformation method. The talk is based on joint works of the speaker with B. Shiffman and C. Ciliberto.

Zaidenberg, Mikhail

2007-01-01

379

Projectively deformable Legendrian surfaces  

CERN Document Server

Consider an immersed Legendrian surface in the five dimensional complex projective space equipped with the standard homogeneous contact structure. We introduce a class of fourth order projective Legendrian deformation called \\emph{$\\,\\Psi$-deformation}, and give a differential geometric characterization of surfaces admitting maximum three parameter family of such deformations. Two explicit examples of maximally $\\, \\Psi$-deformable surfaces are constructed; the first one is given by a Legendrian map from $\\, \\PP^2$ blown up at three distinct collinear points, which is an embedding away from the -2-curve and degenerates to a point along the -2-curve. The second one is a Legendrian embedding of the degree 6 del Pezzo surface, $\\, \\PP^2$ blown up at three non-collinear points. In both cases, the Legendrian map is given by a system of cubics through the three points, which is a subsystem of the anti-canonical system.

Wang, Joe S

2011-01-01

380

Deformations of 3-algebras  

CERN Multimedia

We phrase deformations of n-Leibniz algebras in terms of the cohomology theory of the associated Leibniz algebra. We do the same for n-Lie algebras and for the metric versions of n-Leibniz and n-Lie algebras. We place particular emphasis on the case of n=3 and explore the deformations of 3-algebras of relevance to three-dimensional superconformal Chern--Simons theories with matter.

Figueroa-O'Farrill, José

2009-01-01

 
 
 
 
381

Effect of plastic deformation on structure and mechanical properties of alloy 36NKhTYu exposed to high-energy action  

International Nuclear Information System (INIS)

Purpose of the work is elimination of structure heterogeneousness forming in high-energy action zone, increase of elasticity, strength properties, and cyclic stability of welded joints from 36NKhTYu. It is shown, that application of mechanic-thermal treatment of high-energy action zone leads to elimination structure heterogeneousness and reduction of distinctions in these zones hardness that provide increase to resistance, destruction and sample fatigue life.

2002-01-01

382

Local microstructure during deformation  

International Nuclear Information System (INIS)

The thesis deals with the influence of microstructure on the deformation behavior of alloys: Portevin Le Chatelier (PLC) effect in aluminum based alloys and hot deformation of nickel based alloys. For the PLC effect in Al-Mg alloys, changes in the types of serrations and characteristics of stress drop distributions have no relation to the flow stress. For the Al - Li alloy, the volume fraction of 'delta prime' precipitates is found to decrease as deformation proceeds, and the critical strain as a function of testing temperatures and strain rates shows different trends concerning the size of the precipitates. Hot processing of a Nickel based superalloy (Nimonic 80a) was simulated by Gleeble experiments. Changes in the overall dislocation density are consistent with variances of micro-hardness. A significantly higher micro-hardness near grain boundaries indicates an inhomogeneous dislocation distribution within single grains. Following the deformation, the alloys were annealed. Dislocations and grain boundaries were identified as favorite sites for nucleation of Cr23C6 precipitates. At the early stages of decomposition, the size of the carbides is reduced and their volume fraction is enhanced as a result of deformation. However, the kinetics of homogeneous 'gamma prime' is not influenced by prior deformation. The Cr23C6 carbides do not transform to the equilibrium Cr7C3 phase as the alloy is reheated and held at 1328 K up to 600 s. Dynamic recrystallization is drastically reduced by presence of these carbides. (author)

2003-01-01

383

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.

2008-02-25

384

Effect of charge deformation and geometric relaxation on the dynamics and the thermodynamic properties of the MgO (001) surface  

Science.gov (United States)

Model calculations by Martin and Bilz have indicated that a slight enhancement of effective surface charges may largely account for recent observations on the static (001) MgO surface (low-energy electron diffraction, electron-energy-loss spectroscopy, and x-ray photoemission spectroscopy). The simplest model incorporating the feature of charge enhancement, a modified rigid-ion model, is used in the present work to study the dynamical and thermodynamic properties of this surface. The results are compared with available experimental data.

Lakshmi, G.; de Wette, F. W.

1980-11-01

385

Effect of charge deformation and geometric relaxation on the dynamics and the thermodynamic properties of the MgO (001) surface. II. Shell models  

Science.gov (United States)

Model calculations by Martin and Bilz have indicated that a slight enhancement of effective surface charges may largely account for recent observations on the static MgO(001) surface (low-energy electron diffraction, electron-energy-loss spectroscopy, x-ray-photoemission spectroscopy). In the present work we use some of the modified shell models, proposed by Martin and Bilz, to study the dynamical and thermodynamic properties of this surface. The results are discussed in the light of available experimental data and of earlier theoretical results.

Lakshmi, G.; de Wette, F. W.

1981-02-01

386

Particle-Dependent Deformations of Lorentz Symmetry  

Directory of Open Access Journals (Sweden)

Full Text Available I report results suggesting that it is possible to introduce laws of relativistic kinematics endowing different types of particles with suitably different deformed-Lorentz-symmetry properties. I also consider some possible applications of these results, among which I highlight those relevant for addressing a long-standing challenge in the description of composite particles, such as atoms, within quantum-gravity-inspired scenarios with Planck-scale deformations of Lorentz symmetry. Some of the new elements here introduced in the formulation of relativistic kinematics appear to also provide the starting point for the development of a correspondingly novel mathematical formulation of spacetime-symmetry algebras.

Giovanni Amelino-Camelia

2012-01-01

387

Deformation twinning in ordered intermetallic compounds  

Energy Technology Data Exchange (ETDEWEB)

Mechanistic understanding of deformation twinning in ordered superlattice structures is reviewed, and the inter-relationships between twinning and generalized plastic flow or fracture toughness are discussed. While general discussions refer to all the fcc-based and bcc-based cubic and noncubic ordered intermetallic alloys, specific calculations of the energetic and kinetic aspects of deformation twinning are made for TiAl. The importance of the twin-slip conjugate relationship on high temperature mechanical properties is emphasized. Discussion is given of possible effects of macro- and micro-alloying on twinning propensity. 40 refs., 4 figs., 2 tabs.

Yoo, M.H.; Fu, C.L.; Lee, J.K. (Oak Ridge National Lab., TN (USA))

1989-01-01

388

Deformation based temperature rise: a review  

Energy Technology Data Exchange (ETDEWEB)

The thermomechanical response of material under both elastic and plastic conditions has been used to determine various material properties under monotonic and cyclic loading conditions. The change in temperature at any point/zone of the material indicates the deformation and damage. This paper presents a review concerned with the application of the deformation based temperature rise, mainly in mechanics, and the different temperature measuring techniques employed. The concept is very useful, particularly in installed structures such as pressure vessels and piping, to determine the response in service.

Pandey, K.N.; Chand, Satish

2003-10-01

389

Influence of biocorrosion on microstructure and mechanical properties of deformed Mg-Y-Er-Zn biomaterial containing 18R-LPSO phase.  

UK PubMed Central (United Kingdom)

The microstructure and mechanical properties of as-extruded Mg-8Y-1Er-2Zn (wt%) alloy containing long period stacking ordered (LPSO) phase are comparatively investigated before and after corrosion in a simulated body fluid (SBF) at 37°C. The as-extruded alloy consists of a long strip-like 18R-LPSO phase and some fine lamellae grains formed by primary recrystallization during the extrusion process. The hydrogen evolution volume per day fluctuates between 0.21 and 0.32ml/cm(2) in the immersion test for 240h, and the corresponding corrosion rate is calculated as 0.568mm/y. The corrosion product is determined as Mg(OH)2, whilst a Ca(H2PO4)2 compound is also observed on the surface of the samples. The corrosion site preferentially occurs at the interface between LPSO phase and Mg matrix. Before immersing, the tensile yield strength (TYS), ultimate tensile strength (UTS) and elongation of the alloy are 275MPa, 359MPa, and 19%, respectively. More attractively, these mechanical properties can be maintained even after immersing in SBF for 240h (TYS, UTS and elongation are 216MPa, 286MPa and 6.8%, respectively) because of the existence of high anti-corrosion LPSO phase.

Leng Z; Zhang J; Yin T; Zhang L; Guo X; Peng Q; Zhang M; Wu R

2013-08-01

390

Versal deformations of Leibniz algebras  

CERN Multimedia

In this work we consider deformations of Leibniz algebras over a field of characteristic zero. The main problem in deformation theory is to describe all non-equivalent deformations of a given object. We give a method to solve this problem completely, namely work out a construction of a versal deformation for a given Leibniz algebra, which induces all non-equivalent deformations and is unique on the infinitesimal level.

Fialowski, A; Mukherjee, G; Fialowski, Alice; Mandal, Ashis; Mukherjee, Goutam

2007-01-01

391

Properties of N=90 Isotones within the Mean Field Perspective  

CERN Multimedia

In recent years, the N=90 isotones have been investigated to a large extent in relation to studies of quantum phase transitions. In this paper, we use the mean field approach with pairing-deformation self consistent Total Routhian Surface (TRS) calculations to study the N=90 isotones and neigh- bouring nuclei. The important probes, such as moments of inertia, quadrupole moments, the energy ratio of E(4+1)/E(2+1), octupole and hexadecapole degrees of freedom are considered and the cal- culated results are compared with the available experimental data. From a microscopic point of view, the N=90 isotones characterize the onset of the deformed region and are very well described by mean field calculations. The results are compared with those from other studies in beyond mean-field approximations. Shape coexistence phenomena in the region of interest are discussed.

Ganio?lu, E; Magierski, P

2013-01-01

392

Effects of irradiation temperature, fluence, and heating rate on postirradiation flow properties of cladding under simulated temperature transient heating and deformation conditions  

International Nuclear Information System (INIS)

[en] Irradiation temperature, fluence, and heating rate effects on plastic flow and failure properties of fast reactor cladding were investigated by heating internally pressurized specimens until failure occurred. Specimens tested were from 20 percent cold-worked Type 316 stainless steel cladding, irradiated in the experimental breeder reactor II (EBR-II) at temperatures to 7200C and fluences to 1023 neutrons (n)/cm2(E>0.1 MeV). A decrease of transient failure temperature with increasing irradiation temperature was observed at the ''standard'' heating rate of 5.6 C0/s. This effect became more pronounced for irradiation temperatures above 6000C. Transient failure temperatures also generally decreased with increasing fluence for tests performed at the standard heating rate. 5 refs

1978-07-11

393

Strains, stresses and elastic properties in polycrystalline metallic thin films: in situ deformation combined with x-ray diffraction and simulation experiments  

Energy Technology Data Exchange (ETDEWEB)

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)

Goudeau, P.; Girault, B.; Renault, P.O.; Le Bourhis, E.; Villain, P.; Badawi, F. [LMP, Universite de Poitiers, Avenue Marie et Pierre Curie, 86962 Futuroscope (France); Faurie, D. [Netherlands Institute for Metals Research, Rotterdamseweg 137, 2600 GA Delft (Netherlands); Castelnau, O.; Brenner, R. [LPMTM (CNRS), Universite Paris 13, av. J.B. Clement, F - 93430 Villetaneuse (France); Bechade, J.L. [CEA-Saclay, DEN/DMN/SRMA/LA2M, 91191 Gif-sur-Yvette Cedex (France); Geandier, G.; Tamura, N. [ALS, LBNL, 1 Cyclotron Road, Berkeley, CA 94720 (United States)

2006-07-01

394

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)

[en] 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)

2006-01-01

395

Autogenous Deformation of Concrete  

DEFF Research Database (Denmark)

Autogenous deformation of concrete can be defined as the free deformation of sealed concrete at a constant temperature. A number of observed problems with early age cracking of high-performance concretes can be attributed to this phenomenon. During the last 10 years , this has led to an increased focus on autogenous deformation both within concrete practice and concrete research. Since 1996 the interest has been significant enough to hold international, yearly conferences entirely devoted to this subject. The papers in this publication were presented at two consecutive half-day sessions at the American Concrete Institute’s Fall Convention in Phoenix, Arizona, October 29, 2002. All papers have been reviewed according to ACI rules. This publication, as well as the sessions, was sponsored by ACI committee 236, Material Science of Concrete. The 12 presentations from 8 different countries indicate the broad, global research efforts dealing with autogenous deformation, and the good attendance at the convention – an audience of up to 90 people – shows that this interest is shared by the general concrete community. Attendees left with an understanding of the complexity of the autogenous deformation of concrete – the sessions showed that cooperation and more research are needed. At the ACI 2002 Fall Convention, the international materials research organization, RILEM, took steps to promote further research and cooperation within this area. Two technical committees held initial meetings with the involvement of many ACI members. More collaborative research will be carried out!

2004-01-01

396

When Shape Matters: Deformations of Tiling Spaces  

CERN Document Server

We investigate the dynamics of tiling dynamical systems and their deformations. If two tiling systems have identical combinatorics, then the tiling spaces are homeomorphic, but their dynamical properties may differ. There is a natural map ${mathcal I}$ from the parameter space of possible shapes of tiles to $H^1$ of a model tiling space, with values in $R^d$. Two tiling spaces that have the same image under ${mathcal I}$ are mutually locally derivable (MLD). When the difference of the images is ``asymptotically negligible'', then the tiling dynamics are topologically conjugate, but generally not MLD. For substitution tilings, we give a simple test for a cohomology class to be asymptotically negligible, and show that infinitesimal deformations of shape result in topologically conjugate dynamics only when the change in the image of ${mathcal I}$ is asymptotically negligible. Finally, we give criteria for a (deformed) substitution tiling space to be topologically weakly mixing.

Clark, A; Clark, Alex; Sadun, Lorenzo

2003-01-01

397

Deformation of C isotopes  

CERN Multimedia

Systematic analysis of the deformations of proton and neutron densities in even-even C isotopes was done based on the method of antisymmetrized molecular dynamics. The $E2$ transition strength was discussed in relation to the deformation. We analyze the $B(E2;2^+_1\\to 0^+_1)$ in $^{16}$C, which has been recently measured to be abnormally small. The results suggest the difference of the deformations between proton and neutron densities in the neutron-rich C isotopes. It was found that stable proton structure in C isotopes plays an important role in the enhancement the neutron skin structure as well as in the systematics of $B(E2)$ in the neutron-rich C.

Kanada-Enyo, Y

2004-01-01

398

An investigation of thermal and deformation properties of quartzite at the temperature interval of polymorphic ? - ? transition by neutron diffraction and acoustic emission  

International Nuclear Information System (INIS)

[en] The results of complex application of neutron diffraction and acoustic emission for investigation of the physical properties of synthetic quartz and natural quartzite at the temperature interval of ?-? transition are given. During the experiments the quartzite sample was exposed to heating and also to uniaxial compression. The changes of the lattice spacings of quartzite at the temperature interval of 540-620 C were measured and values of lattice stresses were estimated; estimated lattice stresses several times exceed the applied stresses. It is found that short strong splashes of acoustic emission (AE) occurred when the phase transition was completed; the intensity of those splashes exceeds by two orders the level of AE, caused by the thermal bursting of the sample under heating up to the transition temperature. The assumption is placed that anomalous behaviour of quartz-containing rocks being under relatively small stresses near the phase transition temperature could cause the appearance of the concentrators of local stresses. These stresses are commensurable to the strength of quartz, and initiate the microcracking of the material

2006-01-01

399

PT-symmetrically deformed shock waves  

CERN Document Server

We investigate for a large class of nonlinear wave equations, which allow for shock wave formations, how these solutions behave when they are PT-symmetrically deformed. For real solutions we find that they are transformed into peaked solutions with a discontinuity in the first derivative instead. The systems we investigate include the PT-symmetrically deformed inviscid Burgers equation recently studied by Bender and Feinberg, for which we show that it does not develop any shocks, but peaks instead. In this case we exploit the rare fact that the PT-deformation can be provided by an explicit map found by Curtright and Fairlie together with the property that the undeformed equation can be solved by the method of characteristics. We generalise the map and observe this type of behaviour for all integer values of the deformation parameter epsilon. The peaks are formed as a result of mapping the multi-valued self-avoiding shock profile to a multi-valued self-crossing function by means of the PT-deformation. For some...

Cavaglia, Andrea

2012-01-01

400

Deformed relativistic Hartree Bogoliubov theory in continuum  

CERN Multimedia

A deformed relativistic Hartree Bogoliubov (RHB) theory in continuum is developed aiming at a proper description of exotic nuclei, particularly those with a large spatial extension. In order to give an adequate consideration of both the contribution of the continuum and the large spatial distribution in exotic nuclei, the deformed RHB equations are solved in a Woods-Saxon (WS) basis in which the radial wave functions have a proper asymptotic behavior at large distance from the nuclear center. This is crucial for the proper description of a possible halo. The formalism of deformed RHB theory in continuum is presented. A stable nucleus, 20Mg and a weakly-bound nucleus, 42Mg, are taken as examples to present numerical details and to carry out necessary numerical checks. In addition, the ground state properties of even-even magnesium isotopes are investigated. The generic conditions of the formation of a halo in weakly bound deformed systems and the shape of the halo in deformed nuclei are discussed. We show that...

Li, Lulu; Ring, P; Zhao, En-Guang; Zhou, Shan-Gui

2012-01-01

 
 
 
 
401

Nanolaminate deformable mirrors  

Energy Technology Data Exchange (ETDEWEB)

A deformable mirror formed out of two layers of a nanolaminate foil attached to a stiff substrate is introduced. Deformation is provided by an electrostatic force between two of the layers. The internal stiffness of the structure allows for high-spatial-frequency shapes. The nanolaminate foil of the present invention allows for a high-quality mirror surface. The device achieves high precision in the vertical direction by using foils with accurately controlled thicknesses, but does not require high precision in the lateral dimensions, allowing such mirrors to be fabricated using crude lithography techniques. Such techniques allow structures up to about the meter scale to be fabricated.

Papavasiliou, Alexandros P. (Oakland, CA); Olivier, Scot S. (Santa Cruz, CA)

2009-04-14

402

A Review of Deformable Curves from the Perspective of Chromosome Image Segmentation  

Directory of Open Access Journals (Sweden)

Full Text Available This study surveys deformable curves (active contours) with the aim of identifying a suitable type of deformable curve for the task of chromosome image segmentation. Deformable curves offer a unique and powerful approach to segmentation. They are capable of accommodating variability of biological structures. Deformable curves also support interactive mechanisms that permit expert interaction during the process. The objective of this was to to study the theoretical frameworks of different active contour models, classify the methods according to several properties and compare their properties. This study reviews the deformable curves and their application specifically to the task of chromosome image segmentation.

A. Prabhu Britto; G. Ravindran

2005-01-01

403

Deformation measurements with honeycomb materials for crashpads of balloon gondolas  

Science.gov (United States)

For the damping of the touch-down impact of stratospheric balloon gondolas, crashpads of honeycomb materials from cardboard are commonly used. They are designed in a way that they do not buckle, that the kinetic energy of the gondola can be absorbed at their deformation, and that a sufficient braking distance for the gondola is provided by their height. Furthermore their mass and the dependence of their strength properties on the direction of deformation should be as low as possible. To achieve an optimal compromise of these requirements a dataset of strength properties of different honeycomb products has been established. Of particular interest was the absorbable energy if the honeycomb panels are deformed flatwise or at different angles. Altogether 11 products from 3 manufactures have been tested, each at 3 angles of deformation. The average and peak deformation stress as well as the deformation work per volume and mass as functions of the direction of deformation are expressed by polynomials. Correlations between the deformation work and the thickness of the honeycomb panels are looked at.

Seefeldner, M.; Nordmeyer, H.

2001-08-01

404

Influence des déformations tectoniques sur les caractéristiques pétrophysiques matricielles des réservoirs calcaires Influence of Tectonic Deformation on the Petrophysical Matrix Properties of Limestone Reservoirs  

Directory of Open Access Journals (Sweden)

Full Text Available Cet article présente les principaux résultats d'une étude menée en commun par l'Institut Français du Pétrole (IFP) et la Société Nationale Elf Aquitaine (Production) (SNEA) (P), étude qui avait pour but de rechercher l'influence des contraintes tectoniques sur les propriétés pétrophysiques matricielles des réservoirs calcaires. Ces travaux, ayant porté principalement surle Burdigalien des Alpilles (Provence) et accessoirement sur le Turonien de Mareuil (Aquitaine) et la « Scaglia bianca » du Monte Conero (Ancàne-Itatie), ont permis de mettre en évidence - des variations importantes de la porosité et de la perméabilité en fonction de la position structurale du matériau et, à plus petite échelle, de la courbure des couches; - un double processus de la réduction des porosité et perméabilité : soit par tassement mécanique, soit par cristallisation dans les pores d'une calcite provenant probablement d'une dissolution le long de joints stylolithiques d'origine tectonique. On montre enfin qu'en certaines zones particulières (dans les périclinaux ou à l'aplomb d'accidents profonds jouant en faille inverse) les effets des contraintes tectoniques sur les qualités matricielles peuvent être très importants et survenir avant la structuration des couches par plissement. This article describes the main results of a joint Institut Français du Pétrole (IFP)-Société Nationale Elf Aquitaine (Production) (SNEA) (P) research project on the influence of tectonic stresses on thé petrophysical matrix properties of limestone reservoirs. Research mainly concentrated on the Burdigalien from the Alpilles mountains in ihe Provence région and accessorily on the Turonian from Mareuil in the Aquitaine region and Scaglia Bianca from Monte Conero in Anconia, Italy. The following findings were made: - considerable variations in porosity and permeability can be found, depending on the structural position of the material and, on a smaller scale, on the curve of the loyers; - there is a double porosity and permeability réduction process, either by mechanical settling or by thé crystallization in thé pores of a calcite probably coming from a dissolution occurring along stylolitic joints of tectonic origin. It is also shown that in some specific zones (in periclines or directly underneath deep accidents in thé form of thrust faults) thé effects of tectonic stresses on matrix qualities may be very great and may occur prior to the folding structuration of the loyers.

Trémolières P.; Reulet J.

2006-01-01

405

Deforming Stanley-Reisner schemes  

CERN Multimedia

We study the deformation theory of projective Stanley-Reisner schemes associated to combinatorial manifolds. We achieve detailed descriptions of first order deformations and obstruction spaces. Versal base spaces are given for certain Stanley-Reisner surfaces.

Altmann, Klaus

2009-01-01

406

Deformation in supersymmetric quantum mechanics  

Energy Technology Data Exchange (ETDEWEB)

We present a comprehensive scheme of deformation and apply it to supersymmetric quantum mechanics. We work out the connection with a recently proposed model and explore a new mode of quantum deformation. (orig.)

Bagchi, B. (Dept. of Applied Mathematics, Vidyasagar Univ., Midnapore, West Bengal (India)); Samanta, K. (Dept. of Applied Mathematics, Vidyasagar Univ., Midnapore, West Bengal (India))

1993-08-02

407

Deformation in supersymmetric quantum mechanics  

International Nuclear Information System (INIS)

We present a comprehensive scheme of deformation and apply it to supersymmetric quantum mechanics. We work out the connection with a recently proposed model and explore a new mode of quantum deformation. (orig.).

1993-01-01

408

Superposed Deformations in Nonlinear Viscoelasticity.  

Science.gov (United States)

A short review is given of the Green-Rivlin theory of nonlinear materials with memory. Small viscoelastic deformation following instantaneous finite elastic response is analysed by linearization of the added viscoelastic deformation. Incompressible, initi...

E. J. Appleby E. H. Lee

1964-01-01

409

The influence of severe plastic deformation on the structure and magnetic properties of a Pr-Fe-B-Cu alloy; Influence d`un hypercorroyage sur la structure et les proprietes magnetiques d`un alliage Pr-Fe-B-Cu  

Energy Technology Data Exchange (ETDEWEB)

The influence of severe plastic torsion straining under pressure on the structure and magnetic properties of the alloy Pr20 Fe 73.5 N 5 Cu 1.5 at % is considered in the present work. Deformation results in the formation of an ultrafine-gained structure and subsequent annealing leads to an increase in coercivity to 1500 kA/m. (authors). 9 refs.

Stolyarov, V.; Gynderov, D. [Institute of physics of advenced materials, aviation technical University, (Russian Federation); Popov, A.; Gaviko, V. [Institute of physics of metal (Russian Federation)

1996-12-31

410

Deformation quantization of bosonic strings  

Energy Technology Data Exchange (ETDEWEB)

Deformation quantization of bosonic strings is considered. We show that the light-cone gauge is the most convenient classical description to perform the quantization of bosonic strings in the deformation quantization formalism. Similar to the field theory case, the oscillator variables greatly facilitates the analysis. The mass spectrum, propagators and the Virasoro algebra are finally described within this deformation quantization scheme. (author)

Garcia-Compean, H. [Departamento de Fisica, Centro de Investigacion y de Estudios Avanzados del IPN, Mexico D.F. (Mexico)]. E-mail: compean@fis.cinvestav.mx; Plebanski, J.F. [Departamento de Fisica, Centro de Investigacion y de Estudios Avanzados del IPN, Mexico D.F. (Mexico)]. E-mail: pleban@fis.cinvestav.mx; Turrubiates, F.J. [Departamento de Fisica, Centro de Investigacion y de Estudios Avanzados del IPN, Mexico D.F. (Mexico)]. E-mail: fturrub@fis.cinvestav.mx; Przanowski, M. [Departamento de Fisica, Centro de Investigacion y de Estudios Avanzados del IPN, Mexico D.F. (Mexico); Institute of Physics, Technical University of Lodz, Lodz (Poland)]. E-mail: przan@fis.cinvestav.mx

2000-11-10

411

Discontinuous low temperature deformation of Zr-Sn alloys  

Energy Technology Data Exchange (ETDEWEB)

Mechanical and microstructure properties have been investigated for Zr-Sn alloys with 0.74, 2.85, 4.27 and 6.19 wt.% Sn deformed at 4.2, 77 and 300 K. The tin content plays an important role in the deformation behaviour of the alloys. Serrated yielding has been observed during deformation of Zr-Sn alloy samples with higher tin content if they are deformed at 4.2 K. Twinning has been found to be the microstructure characteristic for Zn-Sn alloy deformed at 4.2 K. A correlation between twins and stress drops has been discussed. It follows from that the origin of the stress drops at low temperatures may be of a mechanical nature. (orig.).

Trojanova, Z.; Lukac, P.; Kral, F.; Kral, R. (Dept. of Metal Physics, Charles Univ., Prague (Czechoslovakia)); Lavrentev, F.F.; Nikiforenko, V.N. (Physico-Technical Inst. of Low Temperature, Ukrainian Academy of Sciences, Kharkov (Ukrainian SSR))

1991-05-15

412

Multi-dimensional potential energy surfaces and non-axial octupole correlations in actinide and transfermium nuclei from relativistic mean field models  

CERN Document Server

We have developed multi-dimensional constrained covariant density functional theories (MDC-CDFT) for finite nuclei in which the shape degrees of freedom \\beta_{\\lambda\\mu} with even \\mu, e.g., \\beta_{20}, \\beta_{22}, \\beta_{30}, \\beta_{32}, \\beta_{40}, etc., can be described simultaneously. The functional can be one of the following four forms: the meson exchange or point-coupling nucleon interactions combined with the non-linear or density-dependent couplings. For the pp channel, either the BCS approach or the Bogoliubov transformation is implemented. The MDC-CDFTs with the BCS approach for the pairing (in the following labelled as MDC-RMF models with RMF standing for "relativistic mean field") have been applied to investigate multi-dimensional potential energy surfaces and the non-axial octupole $Y_{32}$-correlations in N=150 isotones. In this contribution we present briefly the formalism of MDC-RMF models and some results from these models. The potential energy surfaces with and without triaxial deformatio...

Lu, Bing-Nan; Zhao, En-Guang; Zhou, Shan-Gui

2013-01-01

413

Anharmonicities of. gamma. -vibrations in deformed nuclei  

Energy Technology Data Exchange (ETDEWEB)

The anharmonicities of ..gamma..-vibrations are studied within the multiphonon method in different even-even deformed nuclei where the first K/sup ..pi../=2/sup +/ vibrational state appears well below the energy gap: /sup 130/Ce, /sup 162-164/Dy, /sup 164-168/Er, /sup 186/Os. The anharmonicities previously obtained in /sup 168/Er appear to be a general property of these nuclei.

Jammari, M.K.; Piepenbring, R.

1988-10-03

414

Plastic deformation in nanostructure silicon formation  

Directory of Open Access Journals (Sweden)

Full Text Available The quantity and quality analysis of plastic deformation and near-surface silicon layers with nanostructure silicon formation are given in this paper. It is shown, due to high-temperature oxidation and other factors the complex defect structure is generated in near-surface silicon layers. It consists of a disordered silicon layer and a layer of dislocation networks. Silicon dioxide etching and additional chemical treatment allows to obtain nanostructured silicon with given properties.

Smyntyna V. A.; Kulinich O. A.; Yatsunkiy I. R.

2011-01-01

415

[Babies with cranial deformity].  

UK PubMed Central (United Kingdom)

Plagiocephaly was diagnosed in a baby aged 4 months and brachycephaly in a baby aged 5 months. Positional or deformational plagio- or brachycephaly is characterized by changes in shape and symmetry of the cranial vault. Treatment options are conservative and may include physiotherapy and helmet therapy. During the last two decades the incidence of positional plagiocephaly has increased in the Netherlands. This increase is due to the recommendation that babies be laid on their backs in order to reduce the risk of sudden infant death syndrome. We suggest the following: in cases of positional preference of the infant, referral to a physiotherapist is indicated. In cases of unacceptable deformity of the cranium at the age 5 months, moulding helmet therapy is a possible treatment option.

Feijen MM; Claessens EA; Dovens AJ; Vles JS; van der Hulst RR

2009-01-01

416

Fuel bundle deformation model  

Energy Technology Data Exchange (ETDEWEB)

A finite-element model of a 43-element CANFLEX fuel bundle was developed using ANSYS, a commercial finite-element software package. The target application of this bundle deformation model is the prediction of the thermal and mechanical loads a fuel bundle could impart onto its pressure tube under CANDU reactor accident transient conditions. The current version of the bundle model focuses on a small number of key components (fuel, sheath and end plates) and parameters (fuel thermal expansion, fuel/sheath interaction, and end-plate effects). This paper summarizes the current finite element fuel bundle deformation model, the testing done to date on individual components and the plans for future development. (author)

Walters, L.C.; Williams, A.F. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

2003-07-01

417

Fuel bundle deformation model  

International Nuclear Information System (INIS)

A finite-element model of a 43-element CANFLEX fuel bundle was developed using ANSYS, a commercial finite-element software package. The target application of this bundle deformation model is the prediction of the thermal and mechanical loads a fuel bundle could impart onto its pressure tube under CANDU reactor accident transient conditions. The current version of the bundle model focuses on a small number of key components (fuel, sheath and end plates) and parameters (fuel thermal expansion, fuel/sheath interaction, and end-plate effects). This paper summarizes the current finite element fuel bundle deformation model, the testing done to date on individual components and the plans for future development. (author)

2003-01-01

418

[Inserts for foot deformities  

UK PubMed Central (United Kingdom)

Inserts are orthopedic aids in the treatment of foot disorders that result from changes of the static or dynamic situation. Provision of appropriate orthopedic devices can relieve the pain caused by forefoot deformities either in lieu of surgical intervention or in rare cases also following surgical treatment to improve the symptoms of residual pain.Available materials provide support, padding, and cushioning. Inserts are custom-made to measure and/or based on a plaster impression. Determining the indication, prescribing the inlay, and checking the orthosis are the tasks of the physician. One treatment option for relieving the pain of forefoot deformities consists in conservative therapy with an insert combining features of padding and support as well as adjusting a ready-made shoe. The shoe and inlay should constitute a functional unit since often the optimal effect is only achieved with a combination of insert and orthopedic adjustment of the ready-made shoe.

Stinus H; Weber F

2005-08-01

419

[Inserts for foot deformities].  

Science.gov (United States)

Inserts are orthopedic aids in the treatment of foot disorders that result from changes of the static or dynamic situation. Provision of appropriate orthopedic devices can relieve the pain caused by forefoot deformities either in lieu of surgical intervention or in rare cases also following surgical treatment to improve the symptoms of residual pain.Available materials provide support, padding, and cushioning. Inserts are custom-made to measure and/or based on a plaster impression. Determining the indication, prescribing the inlay, and checking the orthosis are the tasks of the physician. One treatment option for relieving the pain of forefoot deformities consists in conservative therapy with an insert combining features of padding and support as well as adjusting a ready-made shoe. The shoe and inlay should constitute a functional unit since often the optimal effect is only achieved with a combination of insert and orthopedic adjustment of the ready-made shoe. PMID:15991037

Stinus, H; Weber, F

2005-08-01

420

Deformed wing virus.  

UK PubMed Central (United Kingdom)

Deformed wing virus (DWV; Iflaviridae) is one of many viruses infecting honeybees and one of the most heavily investigated due to its close association with honeybee colony collapse induced by Varroadestructor. In the absence of V.destructor DWV infection does not result in visible symptoms or any apparent negative impact on host fitness. However, for reasons that are still not fully understood, the transmission of DWV by V.destructor to the developing pupae causes clinical symptoms, including pupal death and adult bees emerging with deformed wings, a bloated, shortened abdomen and discolouration. These bees are not viable and die soon after emergence. In this review we will summarize the historical and recent data on DWV and its relatives, covering the genetics, pathobiology, and transmission of this important viral honeybee pathogen, and discuss these within the wider theoretical concepts relating to the genetic variability and population structure of RNA viruses, the evolution of virulence and the development of disease symptoms.

de Miranda JR; Genersch E

2010-01-01

 
 
 
 
421

Atomic masses and deformations  

International Nuclear Information System (INIS)

[en] This chapter discusses recommendations for nuclear masses, binding energies and ground state deformations, for use in nuclear reaction model calculations. We recommend that the Moeller et al. file moller.dat with data for nearly 9000 nuclides be used for these quantities. The whole region of masses is covered by audi-95.dat, which brings recommended masses for nearly 3000 nuclides based on experimental values. As a general rule, where experimental values exists, they should be used for calculations. (author)

1998-01-01

422

Sprengels deformity: anaesthesia management.  

Directory of Open Access Journals (Sweden)

Full Text Available A 28 years old lady presented with Sprengels deformity and hemivertebrae for Fothergills surgery. Clinically there were no anomalies of the nervous, renal or the cardiovascular systems. She had a short neck and score on modified Mallapati test was grade 2. She was successfully anaesthetised using injection Propofol as a total intravenous anaesthetic agent after adequate premedication with injection Midazolam and injection Pentazocine. Patient had an uneventful intraoperative and postoperative course.

Dave S; Naik L

2000-01-01

423

[Neurogenic foot deformities].  

UK PubMed Central (United Kingdom)

There is a multitude of neurological diseases which may lead to neuro-orthopaedic problems and subsequently to neurogenic foot deformities. For this reason the diagnostician will be consistently surprised that there is a great multitude of different foot abnormalities and that not only the typical spastic talipes equines dominates. Of particular significance here is that these deformities almost always develop progressively, whereas most diseases persist per se, cerebral palsy being a typical case in point. However, in MMC (myelomeningocele) patients, there is also the danger of a worsening of the basic problem in the case of tethered cord syndrome. Unlike congenital talipes equinovarus, neuro-orthopaedic talipes equinovarus often shows over- or undercorrection postoperatively due to a shift in muscle imbalance. It is important, therefore, that the basis of conservative therapy include regular physiotherapy and orthoses during the day and, if necessary, at night. Botulinum toxin has been established as an additional measure for spasticity; however, this cannot always prevent surgical intervention, but is able to delay this to a better point in the development of the child/patient. The present article describes the diversity of neurological deformities and presents conservative as well as surgical therapeutic approaches.

Senst S

2010-01-01

424

Supertransvectants, cohomology, and deformations  

Science.gov (United States)

Over the (1, N)-dimensional real superspace, N = 2, 3, we classify osp(N|2)-invariant binary differential operators acting on the superspaces of weighted densities, where osp(N|2) is the orthosymplectic Lie superalgebra. This result allows us to compute the first differential osp(N|2)-relative cohomology of the Lie superalgebra (N) of contact vector fields with coefficients in the superspace of linear differential operators acting on the superspaces of weighted densities. We classify generic formal osp(3|2)-trivial deformations of the (3)-module structure on the superspaces of symbols of differential operators. We prove that any generic formal osp(3|2)-trivial deformation of this (3)-module is equivalent to its infinitesimal part. This work is the simplest generalization of a result by the first author et al. [Basdouri, I., Ben Ammar, M., Ben Fraj, N., Boujelbene, M., and Kammoun, K., ``Cohomology of the Lie superalgebra of contact vector fields on K1|1 and deformations of the superspace of symbols,'' J. Nonlinear Math. Phys. 16, 373 (2009)].

Ben Fraj, Nizar; Laraiedh, Ismail; Omri, Salem

2013-02-01

425

METHOD AND APPARATUS FOR DETERMINING DYNAMIC DEFORMATION CHARACTERISTICS OF AN OBJECT  

UK PubMed Central (United Kingdom)

Apparatus and methods for measuring a dynamic deformation characteristic of a deformable target surface during a deformation interval. The measurement principles may be applied to a large variety of organic and inorganic materials having a surface that can be deformed by an applied non-contact force. The surface may be light diffusing and non-transparent or non-diffusing and transparent. A device for measuring a dynamic deformation characteristic of an in-vivo cornea during a deformation interval includes