WorldWideScience
 
 
1

Collective properties of octupole-deformed atomic nuclei  

International Nuclear Information System (INIS)

Collective properties of even-even nuclei in the radium region are studied theoretically. Energy of the lowest collective states and reduced probabilities B(E2) and B(E3) of electromagnetic transitions between these states are mainly analysed. The excited states are treated as large-amplitude quadrupole and octupole vibrations coupled with each other. A large anharmonicity of the spectrum and a large value B(E3) of the transition from the first octupole excited state to the ground state are obtained, for octupole-deformed nuclei. A strong dependence of the results on the shape of the potential energy of a nucleus, treated as a function of its deformation, is stressed. (author)

1991-01-01

2

Octupole deformation properties of actinide isotopes within a mean field approach  

CERN Document Server

We discuss the octupole deformation properties of many even-even actinide isotopes. The analysis is carried out in the mean field framework (Hartree-Fock-Bogoliubov approximation) by using the axially symmetric octupole moment as a constraint. A one-dimensional octupole collective Hamiltonian is used to obtain properties like excitation energies or $E1$ and $E3$ transition probabilities of the negative parity band-heads associated to the lowest lying $1^{-}$ and $3^{-}$ states. The evolution of these values with neutron number is discussed and a comparison with available experimental data is made. In order to minimize the uncertainties associated to the energy density functional used, the calculations have been carried out for an assorted set ranging from the BCP1 functional to the finite range Gogny interaction with the D1S, D1N and D1M parametrization.

Robledo, L M; 10.1088/0954-3899/39/10/105103

2012-01-01

3

A review of experimental evidence for octupole deformation  

International Nuclear Information System (INIS)

Experimental evidence for octupole correlations, which lead to octupole instability and octupole deformation of some nuclei, is illustrated through typical examples. Data are considered for both the 220 < A < 230 region and for a few medium mass nuclei

1986-01-01

4

Microscopic study of octupole-deformations in even-even 226-230Th isotopes  

International Nuclear Information System (INIS)

Study of octupole correlations in the actinides has attracted interest because of the predictions that octupole deformation would be present in the Z ? 88 and N ?134 region. These predictions have been explored through a series of experimental studies, which have centred on energy spectra and transition properties. In the present work, the octupole-octupole interaction is incorporated to the pairing plus quadrupole-quadrupole model. The microscopic Cranked Hartree Bogoliubov framework (CHB) is employed with pairing plus quadrupole-quadrupole plus octupole-octupole interaction to study the non-axial nature of 226-230Th.

2013-12-01

5

Octupole Deformed Nuclei in the Actinide Region  

CERN Multimedia

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

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

6

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

7

Experimental tests for stable octupole deformation in actinium-227  

Energy Technology Data Exchange (ETDEWEB)

The question of intrinsic reflection asymmetry or stable-octupole deformation in /sup 227/Ac was studied by the single-proton stripping reactions /sup 226/Ra(/sup 3/He,d)/sup 227/Ac with E/sub 3He/ = 30 MeV and /sup 226/Ra(..cap alpha..,t)/sup 227/Ac with E/sub ..cap alpha../ = 30 MeV and by measuring the magnetic moment of the first excited 3/2/sup +/ 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 /sup 227/Ac. 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 /sup 227/Ac. Furthermore, the results are consistent with the branching ratio determination of the magnetic moment of the first excited state in /sup 227/Ac which is in agreement with the stable-octupole model prediction.

Martz, H.E. Jr.

1986-01-01

8

Experimental tests for stable octupole deformation in actinium-227  

International Nuclear Information System (INIS)

The question of intrinsic reflection asymmetry or stable-octupole deformation in "2"2"7Ac was studied by the single-proton stripping reactions "2"2"6Ra("3He,d)"2"2"7Ac with E/sub 3He/ = 30 MeV and "2"2"6Ra(?,t)"2"2"7Ac 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 "2"2"7Ac. 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 "2"2"7Ac. Furthermore, the results are consistent with the branching ratio determination of the magnetic moment of the first excited state in "2"2"7Ac which is in agreement with the stable-octupole model prediction

1986-01-01

9

New Results on Octupole Collectivity  

International Nuclear Information System (INIS)

Octupole correlations play an important role in determining the level structure of nuclei throughout the periodic chart. Microscopically, octupole correlations are the result of the long-range, octupole-octupole interaction between nucleons occupying pairs of orbitals which differ in both orbital and total angular momentum by 3 units. A review of some of the most recent findings on octupole correlations is given. Emphasis is placed on new results from the actinide region, where two distinct collective modes have long been identified: octupole vibration and octupole deformation. These new results include negative-parity structures which appear to evolve from an octupole vibration into a static octupole deformed mode. In addition, newly observed rotational structures built on an excited 0+ state have been tentatively associated with a double-octupole phonon excitation. These newly observed properties can be successively described by calculations based on the concept of rotational-aligned octupole phonon condensation.

2011-09-23

10

Fast nuclear rotation and octupole deformation  

CERN Document Server

The 150Sm nucleus has been studied to high spins in a measurement of gamma radiation following the 136Xe(18O,4n)150Sm, compound-nucleus reaction at beam energy of 76 MeV. The measurement was performed at NBI Riso using the NORDBALL array. Alternating parity, s=+1 band in 150Sm has been observed up to spin I=22. This band is crossed by two aligned bands, corresponding to a reflection-symmetric shape. After the second crossing the s=+1 band ends abruptly, suggesting that the octupole shape vanishes in 150Sm above spin I=22, as predicted by calculations. Other explanations, assuming continuation of the s=+1 band past the two alignments are also discussed.

Urban, W; Nyberg, J

2001-01-01

11

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

12

Octupole deformation for Ba isotopes in a reflection-asymmetric relativistic mean-field approach  

CERN Multimedia

The potential energy surfaces of even-even $^{142-156}$Ba are investigated in the constrained reflection-asymmetric relativistic mean-field approach with parameter set PK1. It is shown that for the ground states, $^{142}$Ba is near spherical,$^{156}$Ba well quadrupole-deformed, and in between $^{144-154}$Ba octupole deformed. In particular, the nuclei $^{148,150}$Ba with $N=92,94$ have the largest octupole deformations. By including the octupole degree of freedom, energy gaps $N=88$, $N=94$ and $Z=56$ near Fermi surfaces for the single-particle levels in $^{148}$Ba with $\\beta_2\\sim 0.26$ and $\\beta_3\\sim 0.17$ are found. Furthermore, the performance of the octupole deformation driving pairs ($\

Zhang, W; Zhang, S Q

2010-01-01

13

Microscopic and semi-classical treatments of octupole deformation in the light actinides  

Energy Technology Data Exchange (ETDEWEB)

Microscopic and semi-classical descriptions of octupole deformation are compared. New semi-classical results, obtained with the use of a Woods-Saxon potential are presented. Comparisons with experiment are made.

Chasman, R.R. (Argonne National Laboratory, Il (U.S.A.))

1984-06-01

14

Microscopic and semi-classical treatments of octupole deformation in the light actinides  

International Nuclear Information System (INIS)

Microscopic and semi-classical descriptions of octupole deformation are compared. New semi-classical results, obtained with the use of a Woods-Saxon potential are presented. Comparisons with experiment are made

1984-06-01

15

Energy displacement function as a signature for octupole deformation in excited states  

CERN Document Server

Energies for three positive and three negative parity bands predicted by the extended coherent states model (ECSM) in sup 2 sup 2 sup 6 Ra are calculated and used to point out new signatures for octupole deformation in ground as well as in beta and gamma bands. A beat pattern is found by using a new displacement energy function which is more appropriate for a spectrum which exhibits large deviation from a linear J(J+1) dependence. The stability against octupole deformation is revisited from a new point of view. (authors)

Raduta, A A; Ursu, I I

2003-01-01

16

Incipient octupole deformation and parity doublets in the odd mass light actinides  

International Nuclear Information System (INIS)

A non-perturbative method is used to investigate the existence of octupole deformations in the light, odd mass, actinides. Calculated level schemes and B(E3) values are presented for serveral nuclides. Serveral, almost degenerate, parity doublets are found in the calculations. (orig.)

1980-10-20

17

Octupole deformation bands of ?h11/2 in neutron-rich 145,147La nuclei  

International Nuclear Information System (INIS)

Octupole deformation bands built on ?h11/2 orbital in neutron-rich odd-Z145,147La nuclei have been investigated by measuring the prompt ?-rays emitted from the 252Cf source. The alternating parity band structures and strong E1 transitions observed between negative- and positive-parity bands in both nuclei indicate the octupole deformation enhanced by the h11/2 single proton coupling. According to observed energy displacements the octupole deformation becomes stable at the intermediate spin states

1999-03-01

18

Octupole-deformed molecular bands in {sup 21}Ne  

Energy Technology Data Exchange (ETDEWEB)

Cluster states up to 12 MeV in the stable light nucleus {sup 21}Ne, based on the {sup 16}O+n+{alpha} molecular configurations, have been populated in the incomplete-fusion reaction {sup 16}{sub 8}O({sup 7}{sub 3}Li,np){sup 21}{sub 10}Ne at 29.4 MeV. The observation of both intra- and inter-band transitions leads to a re-interpretation of some levels in the K{sup {pi}}=(3)/(2){sup -} and K{sup {pi}}=(1)/(2){sup -} bands. The implications of this re-ordering on the octupole doublet bands are examined. The data allow a more accurate determination of some previously uncertain level energies. The ''missing'' I{sup {pi}}=(5)/(2){sup -} level is also discussed. (orig.)

Wheldon, C.; Thummerer, S.; Bohlen, H.G.; Gebauer, B.; Tumino, A. [Hahn-Meitner-Institut, SF7, Berlin (Germany); Kokalova, Tz.; Oertzen, W. von [Hahn Meitner Inst., Berlin (Germany). SF7; Freie Univ. Berlin (Germany). Fachbereich Physik; Massey, T.N. [Ohio University, Department of Physics and Astronomy, Athens, OH (United States); Angelis, G. de; Axiotis, M.; Gadea, A.; Kroell, Th.; Marginean, N.; Napoli, D.R.; De Poli, M.; Ur, C. [INFN, Laboratori Nazionali di Legnaro, Legnaro (Padova) (Italy); Bazzacco, D.; Lenzi, S.M.; Rossi Alvarez, C.; Lunardi, S.; Menegazzo, R. [Dipartimento di Fisica dell' Universita and INFN, Sezione di Padova, Padova (Italy); Bizzeti, P.G.; Bizzeti-Sona, A.M. [Dipartimento di Fisica dell' Universita and INFN, Sesto Fiorentino (Firenze) (Italy)

2005-12-01

19

Octupole-deformed molecular bands in 21Ne  

International Nuclear Information System (INIS)

Cluster states up to 12 MeV in the stable light nucleus 21Ne, based on the 16O+n+? molecular configurations, have been populated in the incomplete-fusion reaction 168O(73Li,np)2110Ne at 29.4 MeV. The observation of both intra- and inter-band transitions leads to a re-interpretation of some levels in the K?=(3)/(2)- and K?=(1)/(2)- bands. The implications of this re-ordering on the octupole doublet bands are examined. The data allow a more accurate determination of some previously uncertain level energies. The ''missing'' I?=(5)/(2)- level is also discussed. (orig.)

2005-12-01

20

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

 
 
 
 
21

Transition and static moments of octupole-deformed heavy nuclei  

International Nuclear Information System (INIS)

We studied the properties of even-even actinide nuclei using the binary cluster model. Band-mixing calculation of the K?=0- negative parity bands arising from the core nucleus having two different states and with the core and cluster having different effective charges enabled a simultaneous interpretation of the electromagnetic transitions.

2011-10-01

22

Collective excited states of even-even nuclei with quadrupole and octupole deformations  

International Nuclear Information System (INIS)

Full text: Analytical expression for energy levels of excited states of the axial-symmetry nuclei with quadrupole (?2) and octupole (?3) deformations for exponential type potential energy for the surface longitudinal oscillations are obtained in the following form: V=C?02/2 exp[-(? - ?02)/?02], Where: ?2=(B2-?22/B2+B3) + (B2?33/B2+B3), B2 and B3-mass parameters for quadrupole and octupole deformations, C-rigid parameter for surface oscillations, and ?0-deformation parameter in the ground state. Energy levels of excited states with positive and negative parity defined by two parameters: soft parameter relative surface oscillations ?(0???1) and ?? energy parameter, which is the eigenvalue of Schrodinger equation in polar coordinates, ?=0,1,2,.. The obtained theoretical results show, that the proposed model satisfactorily describes experimental values of energy levels of positive and negative parity excited states of even-even nuclei 158,160Dy, 232,234,236,238U, including high spin states. It is also discovered that the exponential type potential energy of the surface oscillations satisfactorily describes only energy levels of rigid nuclei, i.e. when ??1/3. (authors)

2009-09-01

23

Critical-point behaviour of axially deformed nuclei in the octupole degree of freedom  

Energy Technology Data Exchange (ETDEWEB)

The evolution of the octupole excitation is investigated along the Th isotope chain. The isotope {sup 226}Th results to be close to the critical point (square-well potential in the octupole amplitude {beta}{sub 3}). (orig.)

Bizzeti, P.G.; Bizzeti-Sona, A.M. [Dipartimento di Fisica, Universita di Firenze and INFN, Sezione di Firenze, via G. Sansone 1, 50019, Sesto Fiorentino (Italy)

2004-04-01

24

Mean square charge radii of radium isotopes and octupole deformation in the /sup 220-228/Ra region  

Energy Technology Data Exchange (ETDEWEB)

The first investigation of isotope shifts in both the atomic and ionic resonance lines of radium has been carried out using the technique of on-line collinear fast-beam laser spectroscopy at the ISOLDE facility at CERN. The measurements cover 19 isotopes in the mass range 208 less than or equal to A less than or equal to 232 with half-lives between 23 ms and 1600 y. The differences in the nuclear mean square charge radii delta(r/sup 2/) have been evaluated and - together with earlier published spins and moments from the hyperfine structure - related to nuclear deformation. In particular the inversion of the odd-even staggering effect for the isotopes /sup 221/Ra, /sup 223/Ra and /sup 225/Ra can be interpreted by the presence of octupole instability and adds weight to the concept of near-stable octupole deformation in the odd-A isotopes which already explained their spins and magnetic moments.

Ahmad, S.A.; Klempt, W.; Ulm, G.; Neugart, R.; Otten, E.W.; Wendt, K.; Reinhard, P.G.

1988-06-20

25

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

International Nuclear Information System (INIS)

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 Wsh. The value obtained, Wsh?0.5% per prompt fission, is in good agreement with the experimental result. Possibilities for further experimental studies of this effect are discussed. (orig.)

1992-11-01

26

Study of octupole deformation in n-rich Ba isotopes populated via $\\beta$ decay  

CERN Multimedia

We propose to exploit the unique capability of the ISOLDE facility to produce $^{150?151?152}$Cs beams to investigate their radioactive $\\beta$-decay to $^{150?151?152}$Ba. The interest to study this mass region is twofold: from one side these nuclei are expected to show octupole deformations already in their low-lying state, and, on the other hand, gross information on the $\\beta$ decay is highly demanded for nuclear astrophysical model, given the fact that the r-process path lies in the proximity of 1 accessible nuclei. The experiment will be performed with the ISOLDE Decay Station (IDS) setup using the fast tape station of K.U.-Leuven, equipped with 4 Clover Germanium detectors, 4 LaBr$_{3}$(Ce) detectors and 1 LEP HPGe detector. Information on the $\\beta$decay, such as lifetimes and delayed neutron-emission probabilities, will be extracted, together with the detailed spectroscopy of the daughter nuclei, via $\\gamma$ - $\\gamma$ coincidences and lifetimes measurement of specific states.

27

Octupole deformation in neutron-rich 145,147La nuclei  

International Nuclear Information System (INIS)

The level schemes with high spin states in neutron-rich 145,147La nuclei have been established from the study of prompt ?-rays emitted in the spontaneous fission of 252Cf. Many new levels and ? transitions have been identified. The highest spin states in both nuclei were expanded up to (41/2+) and (43/2-) respectively. The alternating parity band structures and strong E1 transitions between negative-and positive-parity bands show strong octupole deformation. The collective bands observed in 145La give evidence for co-existence and competition between symmetric and asymmetric shapes. From the systematic comparison with the neighboring isotones, the s=+ i bands in both nuclei most probably originate from the single-particle ?h11/2 orbital coupling with the neighboring even-even cores, respectively. Band crossing of the ?h11/2 bands was found around ???0.26-0.30 MeV and these backbends are related to the alignment of two i13/2 neutrons from cranked shell model calculations

2000-05-01

28

Investigation of octupole deformations in the Fr217 nucleus by yrast spectroscopy  

International Nuclear Information System (INIS)

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

1988-01-01

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

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

31

Octupole correlations in the heavy elements  

International Nuclear Information System (INIS)

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

1986-06-05

32

Microscopic analysis of the octupole phase transition in Th isotopes  

CERN Document Server

A shape phase transition between stable octupole deformation and octupole vibrations in Th nuclei is analyzed in a microscopic framework based on nuclear density functional theory. The relativistic functional DD-PC1 is used to calculate axially-symmetric quadrupole-octupole constrained energy surfaces. Observables related to order parameters are computed using an interacting-boson Hamiltonian, with parameters determined by mapping the microscopic energy surfaces to the expectation value of the Hamiltonian in the boson condensate. The systematics of constrained energy surfaces and low-energy excitation spectra point to the occurrence of a phase transition between octupole-deformed shapes and shapes characterized by octupole-soft potentials.

Nomura, K; Lu, B -N

2013-01-01

33

Octupole vibrations at high angular momenta  

CERN Document Server

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

Nakatsukasa, T

1995-01-01

34

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

International Nuclear Information System (INIS)

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

1988-01-01

35

Simultaneous quadrupole and octupole shape phase transitions in Thorium  

Energy Technology Data Exchange (ETDEWEB)

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

Li, Z.P.; Song, B.Y.; Yao, J.M. [School of Physical Science and Technology, Southwest University, Chongqing 400715 (China); Vretenar, D. [Physics Department, Faculty of Science, University of Zagreb, 10000 Zagreb (Croatia); Kavli Institute for Theoretical Physics China, CAS, Beijing 100190 (China); Meng, J., E-mail: mengj@pku.edu.cn [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); Department of Physics, University of Stellenbosch, Stellenbosch (South Africa)

2013-11-04

36

Electron scattering from the octupole band in 238U  

International Nuclear Information System (INIS)

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

37

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

38

Octupole deformation in 148Nd  

International Nuclear Information System (INIS)

E1, E2 and E3 matrix elements have been determined for transitions between states up to spin 13 in 148Nd. These values were obtained from Coulomb excitation data using 58Ni and 92Mo ions, projectile excitation using a 208Pb target, and from recoil distance lifetime measurements. The results are consistent with a description of 148Nb having fairly constant intrinsic-frame moments of Q20 = +400 efm2 (?2rms ?+0.22), Q30sum ?1600 efm3 (?3rms ?0.16) for the positive parity states and Q20 =+330 efm2 (?2rms ?+0.18), Q30sum ?2000 efm3 (?3rms ?0.21) for the negative parity states. (author). 23 refs., 3 figs

1992-08-01

39

Octupole softness of superdeformed sup 194 Pb  

Energy Technology Data Exchange (ETDEWEB)

Using parity projection and the generator-coordinate method we investigate the left-right-asymmetric softness of the superdeformed minimum of {sup 194}Pb. The collective wave functions exhibit large octupole dipsersions. Our calculation suggests that above the ground-state superdeformed band there should exist a negative-parity band of similar quadrupole deformation with an excitation energy close to 2 MeV.

Bonche, P.; Krieger, S.J.; Weiss, M.S. (Department of Physics, Lawrence Livermore National Laboratory, Livermore, California 94550 (USA)); Dobaczewski, J. (Institute of Theoretical Physics, Warsaw University, Hoza 69, PL-00681 Warsaw (Poland)); Flocard, H. (Division de Physique Theorique, Institut de Physique Nucleaire, 91406 Orsay CEDEX (France)); Heenen, P. (Service de Physique Nucleaire Theorique, Universite Libre de Bruxelles, CP229, 1050 Bruxelles (Belgium))

1991-02-18

40

Octupole correlation effects in nuclei  

Energy Technology Data Exchange (ETDEWEB)

Octupole correlation effects in nuclei are discussed from the point of view of many-body wavefunctions as well as mean-field methods. The light actinides, where octupole effects are largest, are considered in detail. Comparisons of theory and experiment are made for energy splittings of parity doublets; E1 transition matrix elements and one-nucleon transfer reactions.

Chasman, R.R.

1992-08-01

 
 
 
 
41

Octupole correlation effects in nuclei  

Energy Technology Data Exchange (ETDEWEB)

Octupole correlation effects in nuclei are discussed from the point of view of many-body wavefunctions as well as mean-field methods. The light actinides, where octupole effects are largest, are considered in detail. Comparisons of theory and experiment are made for energy splittings of parity doublets; E1 transition matrix elements and one-nucleon transfer reactions.

Chasman, R.R.

1992-01-01

42

Study of octupole-deformed K=1/2 bands in sup 2 sup 2 sup 7 Th High spin states  

CERN Document Server

High spin states in sup 2 sup 2 sup 7 Th have been populated using the reaction sup 2 sup 2 sup 6 Ra(alpha,3n) sup 2 sup 2 sup 7 Th at a bombarding energy of 33 MeV. The high-spin rotational structures of this nucleus have been refined and extended. In addition, the linking of these structures with the low-spin states known from sup 2 sup 3 sup 1 U alpha decay has allowed a comprehensive decay scheme of this nucleus to be assembled for the first time. Four previously known rotational bands are interpreted as Coriolis-coupled K suppi = 1/2 sup + and K suppi = 1/2 sup - bands, in agreement with predictions using a reflection-asymmetric mean-field approach. The determination of decoupling parameters for these bands is consistent with the a(K suppi = 1/2 sup +) = -a(K suppi = 1/2 sup -) rigid-octupole-rotor expectation. A further rotational band is interpreted as having K suppi = 3/ sup - . Measured D sub 0 /Q sub 0 ratios are consistent with an interpolation, of the values given for neighbouring even-even nuclei...

Hammond, N

2002-01-01

43

Deformation Properties of Unbound Granular Aggregates  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This thesis discusses the resilient and permanent deformation properties of unbound granular aggregates for use in road structures. One of the objectives of the thesis is to identify the influence of the physical properties of the aggregate grains, such as grain size, grain shape, surface texture, mineralogy and mechanical strength through cyclic load triaxial testing. A second objective is to study the effect of water on the deformation properties of materials as well as their frost suscepti...

Uthus, Lillian

2007-01-01

44

Petrophysical Properties of Deformed Sandstone Reservoir  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Shekari-namin, Saeideh

2012-01-01

45

Magnetic properties of cyclically deformed austenite  

Science.gov (United States)

In meta-stable austenitic stainless steels, low cycle fatigue deformation is accompanied by a partial stress/strain-induced solid state phase transformation of paramagnetic ?(fcc) austenite phase to ferromagnetic ?/(bcc) martensite. The measured characteristic of magnetic properties, which are the saturation magnetization, susceptibility, coercivity, retentivity, and the area under the magnetic hysteresis loop are sensitive to the total strain amplitude imposed and the corresponding material behaviour. The morphologies and nucleation characteristics of deformation induced martensites (i.e., ?(hcp), ?/(bcc)) have been investigated through analytical transmission electron microscope. It has been observed that deformation induced martensites can nucleate at a number of sites (i.e., shear band intersections, isolated shear bands, shear band-grain boundary intersection, grain boundary triple points, etc.) through multiple transformation sequences: ?(fcc)??(hcp), ?(fcc)??(hcp)??/(bcc), ?(fcc)? deformation twin ??/(bcc) and ?(fcc)??/(bcc).

Das, Arpan

2014-06-01

46

On the consequences of the octupole instability of nuclei around Ra-Th  

International Nuclear Information System (INIS)

In the present paper, we study vibrations of an even-even nucleus in the two-dimensional, quadrupole and octupole deformation, space. The two degrees of freedom are coupled by the potential energy. Thus, the vibrations are the coupled quadrupole and octupole modes. The hamiltonian is diagonalized in two-dimensional harmonic oscillator basis. The energies and wave functions of the vibrational states as well as the electromagnetic transitions between them are studied. (orig./HSI)

1984-09-03

47

Magnetic properties of deformed superconductors  

International Nuclear Information System (INIS)

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

2011-07-25

48

Inelastic alpha scattering studies of the low-energy octupole resonance  

International Nuclear Information System (INIS)

Beams of 96 and 115 MeV ? particles have been used to study the distribution of isoscalar octupole strength in 18 nuclei from 40Ca to 208Pb. A prominent broad peak (GAMMA approx. 2.5 MeV) is observed at E/sub x/ approx. 30/A/sup 1/3/ MeV in nuclei from 66Zn to 197Au. No broad peak is observed in this excitation energy range in 208Pb or 40Ca and lighter nuclei. The oscillatory angular distributions of the (?,?') reaction exciting this peak are in excellent agreement with l = 3 distorted-wave Born approximation calculations. Studies of the angular range from sigma/sub lab/ = 3.50 to 60 in 116Sn indicate very little contribution from l = 1 strength. Energy- weighted sum rule fractions for this low-energy octupole resonance are generally in the range from 15% to 20%; this corresponds to 1/2 to 2/3 of the expected 1h? octupole strength. The overall distribution of octupole strength in spherical nuclei, including the absence of the low-energy octupole resonance in 40Ca and 208Pb, is in very good agreement with random-phase approximation calculations. The low-energy octupole resonance undergoes a pronounced change in structure in soft-vibrational and deformed nuclei. Theoretical calculations for the low-energy octupole resonance in 154Sm account qualitatively for the data

1978-01-01

49

High spin core-excited isomers and octupole coupling in 213Rn  

International Nuclear Information System (INIS)

The structures of some recently observed high-spin isomers in 213 Rn are considered. Octupole-mixed configurations are shown to account for the measured energies and electromagnetic properties of these levels. 6 refs., 2 figs

1990-01-01

50

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

CERN Multimedia

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

Hoff, P; Kaczarowski, R

2002-01-01

51

Octupole softness of 146 Nd  

International Nuclear Information System (INIS)

The nucleus 146 Nd was studied through the reaction 136 Xe (13 C, 3 n?) at a beam-energy of 54 MeV. The experiment was carried out at NBI, Denmark, with the NORDBALL detector array and a cryogenic target. The use of the large NORDBALL detector array enabled us to obtain good statistics, a total number of ? 100 million ?-? coincidence events being recorded. The ?-? coincidence data were analyzed and for most transitions a DCO ratio was obtained. The level scheme presents relatively long chains of intraband E1 ?-rays linking sequences of stretched E2 gammas, generally observed in the region. The enhanced E1 transition rates in nuclei from the Ba - Sm region was theoretically predicted to be a consequence of the octupole instability (or octupole softness). In this respect, the measured B(E1)/B(E2) branching ratios, related to B(E2) values taken from systematics, indicate a large average value of D0 ? 0.20 efm for the intrinsic dipole moment of medium spins. (Author)

1992-09-21

52

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

2011-01-01

53

Deformation properties of thin polymer films  

Science.gov (United States)

Thin polymer films being processed mostly on rigid substrates experience a "self-orientation" tendency toward a preferred planar orientation of the main-chain of the polymer backbone parallel to the in-plane direction of the film. This tendency increases as the length (called the Kuhn length) between the natural hinges of the polymer increases. The orientation causes the thermoelastic properties of the films to vary from the in-plane direction to the out-of-plane direction. Experimental methods are developed to measure the out-of-plane displacement of polymer films, 10-100 mum thick. The films are adhered to rigid substrates and experience thermal and mechanical displacements in the out-of-plane direction. These displacements are influenced by the constraining effect of the substrates which acts within the plane of the film. Thus, the constraining effect is analyzed in order to separate the true properties of elastic modulus and coefficient of thermal expansion from the as-measured or apparent properties. This analysis also required the knowledge of the in-plane and out-of-plane Poisson's ratio. Techniques are developed to measure these ratios which are also dependent on anisotropy in structure. The anisotropic thermomechanical properties of thin films processed on substrates are found to vary by a factor of 2-10, as compared to the in-plane (or isotropic) values for the polyimides PMDA//PDA and BPDA//PDA and epoxy based adhesives. Under an increase in displacement, the elastic response will eventually suffer an increasing amount of inelastic deformation. This non-elastic deformation has also been investigated based on the relaxation of a stress applied to epoxy based adhesive films sandwiched between two rigid substrates. The amount of stress relaxation decreases as the thickness of the epoxy based adhesive films is decreased, due to a hydrostatic state of stress associated with the presence of an in-plane residual stress which occurs during the thermal curing of the film on the rigid substrates and additional in-plane stress produced by substrate constraint.

Dion, John Bernard

54

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

55

Modified octupoles for damping coherent instabilities  

International Nuclear Information System (INIS)

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

1991-05-06

56

Shape co-existence and octupole correlations in 190Pb  

International Nuclear Information System (INIS)

Full text: Shape co-existence in the neutron-deficient lead nuclei is calculated to take the guise of a potential well with three minima at low spin corresponding to 'spherical', 'oblate' and prolate shapes, dependent on the occupation of specific valence orbitals. Varied spectroscopic evidence for the existence of such minima has been proposed for Pb-188 and Pb-190, including, in Pb-190, long-lived yrast isomers associated with the 11- (oblate) and 12+ (spherical) configurations. To substantiate these assignments, conversion coefficients of the main decays have now been measured using a superconducting, solenoidal electron spectrometer and pulsed beams to obtain high sensitivity. Independent measures of the 11- and 12+ state lifetimes were also obtained. The electric octupole character of the main transition de-exciting the 11- isomer has been confirmed, as has its enhanced nature -- about 20 single-particle units. This is much larger than the strength expected for a spin-flip, proton il3/2 to h9/2 transition, the nominal configuration change between the 11- and 8+ states. Similar 'anomalous' strengths have been observed previously for 11- to 8+ transitions in the neutron deficient polonium isotopes, but they have remained largely unexplained. A partial explanation may lie within a deformed scheme in which the 8+ state arises from population of proton orbitals whose character changes from a predominantly h9/2 parentage near sphericity, to a mixed f7/2/h9/2 configuration at oblate deformation, enabling an enhanced il3/2 to f7/2 octupole-coupled transition. The implications for possible octupole correlations and shape co-existence in the very neutron deficient lead and polonium isotopes will be addressed

2000-12-10

57

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.

Alexander Yu. Churyumov

2012-12-01

58

Mechanical Properties and Deformation Behavior of Bulk Metallic Glasses  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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.

Louzguine-luzgin, Dmitri V.; Louzguina-luzgina, Larissa V.; Alexander Yu. Churyumov

2012-01-01

59

Collective Properties of ''Deformed'' Superheavy Nuclei  

International Nuclear Information System (INIS)

Problem of production of even-even superheavy nuclei in their first excited state 2+ is discussed. Measurement of energy of this state is considered as a way to learn if these nuclei are deformed. Superheavy nuclei situated around the nucleus 270Hs, which according to calculations are expected to be deformed, are studied. Particular attention is given to calculations of the branching ratio p2+/p0+ between ? decay of a nucleus to the 2+ state and to the ground state 0+ of its daughter. Sensitivity of this ratio to various factors appearing in the calculations is discussed. (author)

2001-03-01

60

Measurement of octupole induced decoherence at CESR  

International Nuclear Information System (INIS)

The Landau damping of the transverse oscillations of a relativistic bunch can be enhanced by creating an amplitude-dependent betatron tune spread in the bunch. This tune spread can be created by introducing octupole magnets into the lattice. In order to further their understanding of this mechanism the authors have conducted experiments in CESR where the tune spread of the beam has been measured via measurements of the damping of the centroid motion of the beam after the beam has been kicked. The turn-by-turn transient response of the transverse motion to excitation by injection kickers is measured as a function of octupole current and excitation amplitude. The experimental data is shown to be in good agreement with particle tracking results and the theory of octupole induced decoherence

1991-05-06

 
 
 
 
61

Corneal biomechanical properties from air-puff corneal deformation imaging  

Science.gov (United States)

The combination of air-puff systems with real-time corneal imaging (i.e. Optical Coherence Tomography (OCT), or Scheimpflug) is a promising approach to assess the dynamic biomechanical properties of the corneal tissue in vivo. In this study we present an experimental system which, together with finite element modeling, allows measurements of corneal biomechanical properties from corneal deformation imaging, both ex vivo and in vivo. A spectral OCT instrument combined with an air puff from a non-contact tonometer in a non-collinear configuration was used to image the corneal deformation over full corneal cross-sections, as well as to obtain high speed measurements of the temporal deformation of the corneal apex. Quantitative analysis allows direct extraction of several deformation parameters, such as apex indentation across time, maximal indentation depth, temporal symmetry and peak distance at maximal deformation. The potential of the technique is demonstrated and compared to air-puff imaging with Scheimpflug. Measurements ex vivo were performed on 14 freshly enucleated porcine eyes and five human donor eyes. Measurements in vivo were performed on nine human eyes. Corneal deformation was studied as a function of Intraocular Pressure (IOP, 15-45 mmHg), dehydration, changes in corneal rigidity (produced by UV corneal cross-linking, CXL), and different boundary conditions (sclera, ocular muscles). Geometrical deformation parameters were used as input for inverse finite element simulation to retrieve the corneal dynamic elastic and viscoelastic parameters. Temporal and spatial deformation profiles were very sensitive to the IOP. CXL produced a significant reduction of the cornea indentation (1.41x), and a change in the temporal symmetry of the corneal deformation profile (1.65x), indicating a change in the viscoelastic properties with treatment. Combining air-puff with dynamic imaging and finite element modeling allows characterizing the corneal biomechanics in-vivo.

Marcos, Susana; Kling, Sabine; Bekesi, Nandor; Dorronsoro, Carlos

2014-02-01

62

Symmetry properties of energy bands for some deformed light nuclei  

International Nuclear Information System (INIS)

According to the Bohr's Theory, the first excited states of deformed nuclei are well represented through simple rotational states which are denoted 0+, 2+, 4+, etc., respectively. The ratio of the high excitation energies to the first rotational state (2+) for deformed nuclei demonstrates a well consistency with the integer numbers. These ratio show that there is a symmetry property of deformed nuclei in the excited bands. In this study we have investigated the symmetry properties of energy bands for some deformed light nuclei ( 40K, 52Cr, 55Mn, 58Fe, 59Ni, 60Co) by using of K-quantum number which is projection of the total angular momentum on the axis of symmetry of a nucleus, and also determined energy bands having symmetry

2006-09-06

63

Deformation Properties of TiNi Shape Memory Alloy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In order to describe the deformation properties due to the martensitic transformation and the R-phase transformation of TiNi shape memory alloy, a thermomechanical constitutive equation considering the volume fractions of induced phases associated with both transformations is developed. The proposed constitutive equation expresses well the properties of the shape memory effect, pseudoelasticity and recovery stress.

1995-01-01

64

Some properties of deformed q-numbers  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English 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 p [...] roduct that distributes over the q-sum. Finally, we present different patterns of q-Pascal's triangles, based on q-sum, whose elements are q-numbers.

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

65

Inelastic scattering of pions leading to the lowest octupole states in nuclei  

Energy Technology Data Exchange (ETDEWEB)

The generalized diffraction model of Frahn and Venter is used to study the inelastic scattering of pions around the {delta}-resonance leading to the lowest 3{sup -} states in {sup 18}O, {sup 28}Si, {sup 40,42,44,48}Ca, {sup 58}Ni and {sup 208}Pb. A reasonable good description of the angular distributions is obtained in most cases and the octupole deformation lengths are extracted.

Hai, E.; Soheli, S. [Shah Jalal Univ. of Science and Technology, Sylhet (Bangladesh). Dept. of Physics; Rahman, Md.A.; Sen Gupta, H.M. [Dhaka Univ., Dhaka (India). Dept. of Physics

1999-09-01

66

Nuclear magnetic dipole properties and the triaxial deformation  

CERN Document Server

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

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

2002-01-01

67

Deformation properties of sintered tungsten-based heavy alloys  

Science.gov (United States)

The deformation properties of tungsten-based sintered alloys are studied. Plasticity diagrams are plotted for these alloys at deformation temperatures up to 900°C and various state-of-stress schemes. The properties of the tungsten-based sintered alloys are determined during alternating deformation. The joint action of the temperature (up to 900°C) and the state of stress on the ductility of the tungsten-based sintered alloys is analyzed. The results obtained are used to simulate damage accumulation for various methods of strain hardening of heavy alloys (rotational reduction, hydraulic forging, rolling in multiroll passes). Hydraulic forging is considered, and the limiting reductions are determined using the condition of impossible irreversible metal microfracture.

Smirnov, S. V.; Nesterenko, A. V.; Bykov, V. N.; Mikhailov, V. G.

2007-12-01

68

Perturbation analysis of octupoles in circular accelerators  

International Nuclear Information System (INIS)

The octupole effects in a circular accelerator are analyzed using a first-order canonical perturbation theory. It is shown that, to the first order, the nonlinear amplitude-dependent tune shifts due to an octupole are composed of two types: terms of second order and terms of fourth order in betatron-oscillation amplitudes. The fourth-order part of tune shifts is expressed in terms of distortion functions. Distortion functions are also expanded in harmonics to express the higher-order tune shifts in harmonically expanded form. Finally, the results are applied to an accelerator and compared with the results of numerical tracking of particles. Laskar's algorithm for numerical analysis of the fundamental frequency is used to determine tunes from the tracking data, in which the error becomes inversely proportional to the cube of the number of data points. (author)

1998-06-01

69

Perturbation analysis of octupoles in circular accelerators  

Energy Technology Data Exchange (ETDEWEB)

The octupole effects in a circular accelerator are analyzed using a first-order canonical perturbation theory. It is shown that, to the first order, the nonlinear amplitude-dependent tune shifts due to an octupole are composed of two types: terms of second order and terms of fourth order in betatron-oscillation amplitudes. The fourth-order part of tune shifts is expressed in terms of distortion functions. Distortion functions are also expanded in harmonics to express the higher-order tune shifts in harmonically expanded form. Finally, the results are applied to an accelerator and compared with the results of numerical tracking of particles. Laskar`s algorithm for numerical analysis of the fundamental frequency is used to determine tunes from the tracking data, in which the error becomes inversely proportional to the cube of the number of data points. (author)

Moohyun Yoon [Dept. of Physics, Pohang Univ. of Science and Technology (POSTECH), Pohang (Korea, Republic of)

1998-06-01

70

Nuclear magnetic dipole properties and the triaxial deformation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Nuclear magnetic dipole properties of ground bands and gamma-vibrational bands are studied for the first time using the triaxial projected shell model approach. The study is carried out for the Dy and Er isotopic chains, ranging from transitional to well-deformed region. It is found that the g-factor ratio of the 2^+ state in ground bands to that of gamma-bands, r=g(2^+, gamma-vib)/g(2^+, ground), varies along an isotopic chain. With the gamma-deformations, which best reprod...

Sun, Yang; Sheikh, Javid A.; Long, Gui-lu

2002-01-01

71

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

72

Nanomechanical properties of poly(l-lactide) nanofibers after deformation.  

Science.gov (United States)

Atomic force microscopy (AFM) technique was used to investigate the nanomechanical properties of poly(l-lactide) (PLLA) nanofibers produced by the thermally induced phase separation (TIPS) method. Firstly, AFM-based nanolithography was employed to produce localized deformations on the surface of single PLLA nanofiber, in which the AFM tip served as a nanoscale burin to draw a scratch longitudinally along the nanofiber. Secondly, the morphology and physical properties of the nanofiber before and immediately after the deformation were characterized with AFM and force spectroscopy measurement. During the initial stage of TIPS process, the crystallization of PLLA resulted in a regular arrangement of crystalline domains along the thinner fibrils which then assembled laterally into larger nanofibers. The deformation due to the nanoindentation and plowing with the probe induced structural variation of PLLA nanofibers and led to a functional consequence in their nanomechanical properties. The region after deformation had a higher adhesion force and elastic modulus, probably because the polymer chains became more compact and ordered under both compression and shear stresses. PMID:24905683

Shao, Jundong; Wang, Yingjun; Chen, Xiaofeng; Hu, Xiaomeng; Du, Chang

2014-08-01

73

Deuteron electric quadrupole and octupole polarizabilities  

CERN Document Server

The direct transition-matrix approach to determination of the electric polarizabilities of quantum bound systems developed in my recent work is applied to study the electric multipole polarizabilities of a two-particle bound complex with a central interaction between the particles. Expressions for the electric quadrupole and octupole polarizabilities of the deuteron are derived and their values in the case of the S-wave separable interaction potential are calculated.

Kharchenko, V F

2012-01-01

74

Some New Properties Concerning the q-DEFORMED Calculus and the q-DEFORMATION of the Diffusion Equation  

Science.gov (United States)

In this paper, we introduce some new properties concerning the q-derivative and q-integral. Using these properties, we construct the q-deformation of the diffusion equation. Two types of the q-deformed diffusion equations are possible. One is expressed in terms of the ordinary time derivative and another is expressed in terms of the q-derivative.

Chung, Won Sang; Jung, Min

2013-07-01

75

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

76

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

77

Collective and intrinsic motion of nuclei with quadrupole-octupole degrees of freedom  

International Nuclear Information System (INIS)

The collective model of nuclear coherent quadrupole-octupole oscillations and rotations gives a specific test for the influence of Coriolis interaction between the even-even core and the unpaired nucleon on the split parity-doublet spectra in odd-mass nuclei. It provides model estimations for the angular momentum projection K on the intrinsic symmetry axis and the related intrinsic nuclear structure. Based on this result we propose a study of the connection between collective shape characteristics and the intrinsic reflection-asymmetric shell structure of the nucleus. The analysis of the Coriolis interaction with deformed reflection-asymmetric shell-model calculations shows consistency with the results of the model of coherent quadrupole-octupole motion

2007-09-24

78

The electrochemical properties of the cyclic deformed passive metals  

International Nuclear Information System (INIS)

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

2004-09-12

79

Strength and Deformation Properties of Tertiary Clay at Moesgaard Museum  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The tertiary clay at Moesgaard Museum near Aarhus in the eastern part of Jutland in Denmark is a highly plastic, glacially disturbed nappe of Viborg Clay. The clay is characterised as a swelling soil, which could lead to damaging of the building due to additional heave of the soil. To take this characteristic, as well as the strength and deformation properties, into account during the design phase, two consolidation tests and one triaxial test have been conducted. This paper evaluates the res...

Kaufmann, Kristine Lee; Nielsen, Benjaminn Nordahl; Augustesen, Anders Hust

2010-01-01

80

Properties of europium isotope nuclei  

International Nuclear Information System (INIS)

A review of experimental and theoretical data on the properties of the sup(149-155)Eu nucleus proton-, deuteron- and neutron excited states for the transition region of deformation is presented. A smooth change deformation of this nuclei has been shown to be dependent on excitation energy and mass number. For sup(149)Eu there have observed nuclei of various forms in various proton orbits. For more deformed nuclei of sup(153, 154, 155)Eu isotopes there have detected intensive fragmentation of wave functions even of low excited states which is due to the Coriolis interaction, the residual interaction of external unpaired nucleons and to the effect of quadrupole and octupole vibrations

1985-01-01

 
 
 
 
81

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

International Nuclear Information System (INIS)

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

2000-06-02

82

Octupole focusing in transport and acceleration systems  

International Nuclear Information System (INIS)

The radio-frequency quadrupole (RFQ) linac is capable of accelerating high-current, low-velocity RFQ and higher velocity accelerating structures, the current bottleneck still typically occurs within the FRQ. This limiting current is quite high in most cases, but linacs with even higher currents may be required in the future. We have begun a study of higher multipole systems to determine their capability for focusing and accelerating very high currents. We have chosen first to examine a radio-frequency octupole (RFO) transport system, and have developed a smooth-approximation analytical description that includes the conditions for input radial matching of a zero space-charge beam. Further, we have constructed a multiparticle beam-dynamics simulation program that accepts the low-current matched beam and gradually increases the beam current as it is transported. This results in a matched high-current beam, and the procedure can be used to determine the saturation-current limit of a periodic octupole system. As expected, at high currents the beam develops a hollow radial distribution that reduces the space-charge defocusing; initial results show that high currents can be transported. For acceleration, we have formulated the design parameters for a section of RFO linac, including the potential function, acceleration, and focusing efficiencies, and the geometry of the radially modulated pole tips

1982-02-01

83

Persistence of octupole correlations in $^{231}/Ra$  

CERN Multimedia

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 +or-/ and K/sup pi /=1 /2/sup +or-/ 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. (42 refs).

Fraile-Prieto, L M; Mach, H; Boutami, R; Aas, A J; Fogelberg, B; Gracía-Raffi, L M; Grant, I S; Gulda, K; Hagebø, E; Kurcewicz, W; Kvasil, J; López, M J; Løvhøiden, G; Martínez, T; Rubio, B; Taín, J L; Tengblad, O

2001-01-01

84

Effect of deformation diagram on molybdenum structure and properties  

International Nuclear Information System (INIS)

Effect of deformation diagram on a tendency to lamination and mechanical properties of disks made of molybdenum alloy is studied. Investigated samples were subjected to hot rolling or forging. X-ray structural analysis of texture is carried out along with estimation of the level of mechanical properties across item cross section. Sample mechanical bending tests were conducted. Sample microstructure is also studied. It is shown that rolled molybdenum has a tendency to lamination, but forged molybdenum is free of such a tendency. Forged sample ductility is practically equal in all directionse but rolled sample ductility in a surface layer is high and decreases with depth. A conclusion is drawn that forged sample grains in a setting surface are equiaxial, but distinct deformation texture is observed for rolled samples and their grains are elongated in the direction of rolling. A conclusion is made that a flow diagram of the process of disk fabrication by forging or stamping ppovides a necessary complex of physicomechanical properties of metal as compared to polling, and metal discharge coefficient decreases sharply in this case

1984-01-01

85

Effect of deformation followed by nitridation on niobium alloys properties  

International Nuclear Information System (INIS)

Effect of preliminary plastic deformation of VN-2AEh and VN-3 niobium alloys on formation of nitridated layer and its properties has been studied. Samples have been subjected to rolling at normal temperature to obtain 1 mm thick sheets with summary percentage of reduction in area 25, 50, 75 and 90%. Nitridation has been carried out at 1000, 1100 and 1200 deg C during 1, 3 and 6 h in the medium of pure nitrogen. It is found out that nitridation results in formation of a nitride zone on the surface and a zone of internal nitridation in niobium alloys. The thickness of these zones increases with saturation temperature and duration and changes in an extremal way depending on the degree of preliminary plastic deformation during the rolling. The highest thickness of the internal nitridation zone is observed in 50%-cold-worked smaples, the nitride zone thickness there with is minimal. Niobium alloys deformed before nitridation with low degrees below 50%) are of the highest heat resistance and of the least wear resistance

1983-01-01

86

Structure, inelastic properties and deformation behavior of ultrafine-grained titanium  

International Nuclear Information System (INIS)

Investigation results are presented for the structure, inelastic properties, deformation behavior, strength and plasticity of titanium with an ultrafine-grained microstructure resulted from equal-channel angular pressing. A special attention is given to grain boundary inelasticity and thermal and thermomechanical effects on deformation behavior and plastic deformation localization on meso- and macroscale levels. The influence of cold plastic deformation of ultrafine-grained titanium on grain boundary inelasticity and temperature dependence of mechanical properties is under consideration

2004-09-01

87

Rock mass deformation properties of closely jointed basalt  

International Nuclear Information System (INIS)

The deformational behavior of the Columbia River basalt is being investigated as part of a comprehensive site characterization program intended to determine the feasibility of constructing a nuclear waste repository in basalt at Hanford, Washington. Direct field measurements were conducted in a 2-m cube of basalt to obtain truly representative rock mass deformation properties. Load was applied to the test block in three orthogonal directions through the use of flat jacks in two perpendicular planes and a cable anchor system in the third. This configuration allowed the block to be placed in a simulated triaxial stress state at stress levels up to 12.5 MPa. The deformation at the center of the test block was monitored through the use of an optical measurement system developed for this project. The results indicate that the vertically oriented columnar joints have a significant influence on the deformation behavior of the basalt. The modulus in the direction parallel to the column axis was approx. 30 GPa, while the modulus value perpendicular to the columns was approx. 20 GPa. Laboratory measurements of intact specimens taken from this area yielded a value of 80 GPa with no indication of anisotropy. Hysteresis was observed in all loading cycles, but was distinctly more pronounced perpendicular to the column axis, indicative of significant joint displacement in this direction. The results of this test represent the first true rock mass modulus data obtained in closely jointed rock on a large scale. These measurement methods have eliminated many of the ambiguities associated with borehole jacking and surface measurement techniques

1982-01-01

88

Temperature and pressure dependence of the optimized soft-sticky dipole-quadrupole-octupole water model  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The soft-sticky dipole-quadrupole-octupole (SSDQO) potential energy function for a coarse-grained single-site water model has Lennard-Jones interactions and an approximate multipole expansion for the electrostatics. Here, the Lennard-Jones parameters and multipole moments of SSDQO were optimized so that the structural, thermodynamic, dynamic, and dielectric properties agreed with experimental values of liquid water at ambient conditions. Using these parameters, the temperature and pressure de...

Te, Jerez A.; Ichiye, Toshiko

2010-01-01

89

Quadrupole and octupole correlations in normal, superdeformed and hyperdeformed states of {sup 194}Pb  

Energy Technology Data Exchange (ETDEWEB)

Quadrupole and octupole correlations in {sup 194}Pb are investigated by means of the generator coordinate method. Static microscopic wave functions are obtained by constrained Hartree-Fock+BCS calculations using the effective interaction SkM*. Quadrupole deformations from ground state to hyperdeformation region are included. Superdeformed band heads of both parities are predicted. The depopulation of the even superdeformed band is calculated. The odd-parity superdeformed band slowly decays to the ground even-parity superdeformed band over many E1 transitions. ((orig.)).

Meyer, J. [Lyon-1 Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire; Bonche, P. [Department of Physics, LLNL, Livermore, CA 94550 (United States); Weiss, M.S. [Department of Physics, LLNL, Livermore, CA 94550 (United States); Dobaczewski, J. [Institute of Theoretical Physics, Warsaw University, Hoza 69, PL-00-681 Warsaw (Poland); Flocard, H. [Division de Physique Theorique, Institut de Physique Nucleaire, 91406 Orsay Cedex (France); Heenen, P.H. [Service de Physique Nucleaire Theorique, U.L.B-C.P. 229, B 1050 Brussels (Belgium)

1995-06-12

90

Identification of 109Mo and possible octupole correlations in 107,109Mo  

International Nuclear Information System (INIS)

Ten new transitions in 107Mo have been observed and levels in 109Mo are identified for the first time in a ?-?-? coincidence study from the spontaneous fission of 252Cf with 72 Compton suppressed Ge detectors in Gammasphere. Two sets of bands, each set intertwined by E1 transitions are observed in 107Mo and one such set in 109Mo. The observed level schemes are interpreted in terms of possible octupole deformation originating from the strong interaction of the h11/2 and d5/2 neutron shells. copyright 1997 The American Physical Society

1997-09-01

91

Octupole deformation in "2"2"6Th  

International Nuclear Information System (INIS)

Sources of "2"3"0U - resulting from the ?"- decay of "2"3"0Pa produced in the reaction "2"3"2Th(p,3n) with 34 MeV protons - were purified and used to determine the half life of the 230.4 keV 1"- state in "2"2"6Th. Using the Doppler shift method, following ? decay of "2"3"0U, a value T_1_/_2 = 3.5 ± 1.2 ps was determined. The half life of the 226.4 keV 4"+ state was also measured as T_1_/_2 = 145 ± 20 ps. The absolute probabilities in Weisskopf units of the 230 keV and 158 keV ? transitions depopulating the 1"- state were determined as (2.50 ± 0.86) x 10"-"3 and (4.54 ± 1.55) x 10"-"3 respectively. Experimental values of the intrinsic dipole moment, D_0, and of D_0/Q_0, were determined as 0.27 ± 0.05 e.fm and (3.5 ± 1.0) x 10"-"4 fm"-"1. These data have been compared with theories and experiment. (authors)

1999-01-01

92

Two-octupole-phonon states in 146,148Gd  

International Nuclear Information System (INIS)

Recently the multi-octupole-phonon states have been observed in 146,148Gd and the relevant B(E3) values have been measured. We give a report of our microscopic calculations on the collective multi-octupole-phonon-excited states in these nuclei by using the Dyson boson mapping method. It has been clarified that not only the strong collectivity in the octupole modes in these nuclei but also the coupling with the single-particle modes work together to bring about the highly enhanced B(E3) values in 148Gd. (author)

1995-03-01

93

On the octupole excitation in 236U  

International Nuclear Information System (INIS)

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

1983-10-01

94

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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.

Jakobsen, Bo

2008-01-01

95

Transient deformation properties of Zircaloy for LOCA simulation. Final report  

International Nuclear Information System (INIS)

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

1978-01-01

96

Fluid and ionic transport properties of deformed salt rock  

International Nuclear Information System (INIS)

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

1984-01-01

97

Properties of highly deformed tungsten alloys for vacuum technology  

International Nuclear Information System (INIS)

The powder metallurgical production and applications of tungsten alloys are briefly reviewed with emphasis on wires containing dispersed thoria for applications under vacuum. The properties of pure and Al-K-Si doped tungsten wire, of doped tungsten wire with 1 and 2% thoria added as powder and as thorium hydrosol, of undoped W2Th02, W2Th02 sol, and of W5Re are compared and discussed. The tensile strength, elongation and brittle-ductile transition temperature are given for W2Th02 as a function of deformation history up to 14000C. The effect of annealing in hydrogen at up to 24000C on the mechanical properties of 06. mm diameter wire of tungsten and eight tungsten materials has been determined. In addition to the determination of recrystallisation temperatures and electric conductivities, the results of creep tests are discussed. Sag tests were carried out on the wires and creep curves were recorded at 24500C in hydrogen and in vacuum. The results are correlated with scanning electron micrographs. Finally, the mechanical properties of 0.1 mm thick foil of pure and Al-K-Si doped tungsten, W10Re, and W2Th02 are described. (author)

1977-05-26

98

Deformation-induced microstructures: analysis and relation to properties  

Energy Technology Data Exchange (ETDEWEB)

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

Bilde-Soerensen, J.B.; Carstensen, J.V.; Hansen, N.; Juul Jensen, D.; Leffers, T.; Pantleon, W.; Pedersen, O.B.; Winther, G

1999-07-01

99

Effect of Degree of Deformation on the Mechanical Properties of High Temperature Thermomechanically Treated Steel  

Directory of Open Access Journals (Sweden)

Full Text Available The development of high strength materials, coupled with good formability, has always been the aim of material scientists. The effect of degree of deformation on the mechanical properties of high temperature themomechanically treated steel (HTMT has been investigated in this study. It has shown that an increase in percent deformation results in improvement in mechanical properties. In order to have maximum strengthening, heavy deformation and low finishing temperature should be chosen.

J.A. Omotoyinbo

2006-01-01

100

Microstructure and mechanical properties of precipitation hardened aluminum under high rate deformation  

International Nuclear Information System (INIS)

This chapter attempts to correlate the shock compression and quasistatic deformation of 6061-T6 aluminium. Examines recovered specimens which have been shock loaded, and compares results with both static and dynamic mechanical property measurements. Discusses experimental procedures (reshock and unloading experiments, shock recovery techniques, metallographic techniques and coldwork experiments); dynamic strength and wave-profile properties (strength and shear-stress states on the Hugoniot, steady-wave risetime and viscosity); quasistatic and shock metallography studies (metallography of quasistatically deformed material; metallography of shock deformed specimens; comparison of static and shock deformation; correlation of hardness and dynamic strength measurements); and thermal trapping calculations in shocked aluminium (heterogeneous deformation and adiabatic heating in shock-wave loading; energy and risetime relations under steadywave shock compression; heterogeneous temperature calculations in aluminium). Concludes that heterogeneous shear deformation appears to play a role in the dynamic deformation process

1983-01-01

 
 
 
 
101

Nonaxial-octupole Y_{32} correlations in N = 150 isotones from multidimensional constrained covariant density functional theories  

CERN Document Server

The non-axial reflection-asymmetric $\\beta_{32}$ shape in some transfermium nuclei with N=150, namely $^{246}$Cm, $^{248}$Cf, $^{250}$Fm, and $^{252}$No are investigated with multidimensional constrained covariant density functional theories. By using the density-dependent point coupling covariant density functional theory with the parameter set DD-PC1 in the particle-hole channel, it is found that, for the ground states of $^{248}$Cf and $^{250}$Fm, the non-axial octupole deformation parameter $\\beta_{32} > 0.03$ and the energy gain due to the $\\beta_{32}$ distortion is larger than 300 keV. In $^{246}$Cm and $^{252}$No, shallow $\\beta_{32}$ minima are found. The occurrence of the non-axial octupole $\\beta_{32}$ correlations is mainly from a pair of neutron orbitals $[734]9/2$ ($\

Zhao, Jie; Zhao, En-Guang; Zhou, Shan-Gui

2012-01-01

102

Octupole correlations at superdeformed shape in the Hg-Pb region - including nonaxial components  

International Nuclear Information System (INIS)

We investigate octupole correlations at strongly elongated (axis ratio close to 2:1) quadrupole shapes in the Hg-Pb region including nonaxial components of the octupole mean field. Within the cranked Strutinsky method we find the variation of octupole stiffness with rotational frequency and with the aid of cranking mass parameters we estimate octupole vibration frequencies. The strongest octupole effects are predicted due to the ?=0 and 2 components of the octupole tensor, the estimated oscillation frequencies ranging from 1.1 to 1.6 MeV. (orig.)

1992-01-02

103

Octupole correlations at superdeformed shape in the Hg-Pb region - including nonaxial components  

Energy Technology Data Exchange (ETDEWEB)

We investigate octupole correlations at strongly elongated (axis ratio close to 2:1) quadrupole shapes in the Hg-Pb region including nonaxial components of the octupole mean field. Within the cranked Strutinsky method we find the variation of octupole stiffness with rotational frequency and with the aid of cranking mass parameters we estimate octupole vibration frequencies. The strongest octupole effects are predicted due to the {mu}=0 and 2 components of the octupole tensor, the estimated oscillation frequencies ranging from 1.1 to 1.6 MeV. (orig.).

Skalski, J. (Physique Nucleaire Theorique et Physique Mathematique, Univ. Libre, Brussels (Belgium))

1992-01-02

104

Octupole collectivity in $^{220}$Rn and $^{224}$Ra  

CERN Document Server

Collective properties of the radioactive nuclei $^{220}$Rn and $^{224}$Ra have been studied via Coulomb excitation of a $2.8$~A.MeV radioactive ion beam (RIB) incident upon $^{60}$Ni, $^{112,114}$Cd and $^{120}$Sn targets. The experiments took place at the REX-ISOLDE RIB facility, CERN. De-excitation $gamma$-ray yields following multiple-step Coulomb excitation were detected in coincidence with recoiling target nuclei in the Miniball spectrometer. For the first time, $B(E3;3^{+} ightarrow0^{+})$ values have been directly measured with a radioactive ion beam. In the process, $^{224}$Ra becomes the heaviest post-accelerated RIB to date at ISOLDE (with the possible exception of the quasi-stable $^{238}$U). The measurements presented in this thesis represent a tripling of the number of nuclei around $Zsimeq88$ and $Nsimeq134$, for which direct measurements of the octupole collectivity have been performed. The only previous measurements being for the relatively long-lived $^{226}$Ra. The $gamma$-ray yields, in con...

Gaffney, Liam Paul

105

Ground and Structure Deformation 3d Modelling with a Tin Based Property Model  

Science.gov (United States)

With the development of 3D( three-dimensional) modeling and visualization, more and more 3D tectonics are used to assist the daily work in Engineering Survey, in which the prediction of deformation field in strata and structure induced by underground construction is an essential part. In this research we developed a TIN (Triangulated Irregular Network) based property model for the 3D (three dimensional) visualization of ground deformation filed. By record deformation vector for each nodes, the new model can express the deformation with geometric-deformation-style by drawing each node in its new position and deformation-attribute-distribution-style by drawing each node in the color correspond with its deformation attribute at the same time. Comparing with the volume model based property model, this new property model can provide a more precise geometrical shape for structure objects. Furthermore, by recording only the deformation data of the user-interested 3d surface- such as the ground surface or the underground digging surface, the new property model can save a lot of space, which makes it possible to build the deformation filed model of a much more large scale. To construct the models of deformation filed based on TIN model, the refinement of the network is needed to increase the nodes number, which is necessary to express the deformation filed with a certain resolution. The TIN model refinement is a process of sampling the 3D deformation field values on points on the TIN surface, for which we developed a self-adapting TIN refinement method. By set the parameter of the attribute resolution, this self-adapting method refines the input geometric-expressing TIN model by adding more vertexes and triangles where the 3D deformation filed changing faster. Comparing with the even refinement method, the self-adapting method can generate a refined TIN model with nodes counted less by two thirds. Efficiency Comparison between Self-adapting Refinement Method and Even Refinement Method For one instance

TIAN, T.; Zhang, J.; Jiang, W.

2013-12-01

106

Nonclassical Properties of Q-Deformed Superposition Light Field State  

Science.gov (United States)

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

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

1996-01-01

107

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

2010-03-01

108

Thermal properties of a solid through q-deformed algebra  

CERN Document Server

We address the study of the thermodynamics of a crystalline solid by applying q-deformed algebras. We based part of our study by considering both Einstein and Debye models. We have mainly explored the q-deformed thermal and electric conductivities as a function of the Debye specific heat. The results led to the interpretation of the q-deformation acting as a factor of disorder or impurity modifying the characteristics of a crystalline structure as, for example, in the case of semiconductors.

Marinho, A A; Chesman, C

2011-01-01

109

Deformation effect on properties and fine structure of invar  

International Nuclear Information System (INIS)

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

1980-01-01

110

Deformation properties of osmium, platinum, mercury isotopes from self-consistent calculations  

International Nuclear Information System (INIS)

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 SIII. 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. (orig.)

1981-11-09

111

Influence of deformation on the fluid transport properties of salt rocks  

Digital Repository Infrastructure Vision for European Research (DRIVER)

While the fluid transport properties of rocks are well understood under hydrostatic conditions, little is known regarding these properties in rocks undergoing crystal plastic deformation. However, such data are needed as input in the field of radioactive waste disposal in salt formations. They are also needed to understand deformation, shear zone evolution and associated fluid movement, metamorphism and mineralization in the deep crust and even upper mantle. The present stud...

Peach, C. J.

1991-01-01

112

Octupole correction system for the accelerating-storage complex  

International Nuclear Information System (INIS)

The betatron frequency spread and difference coupling resonance caused by cubic nonlinearity of the accelerating-storage complex (ASC) dipoles and quadrupoles are considered. Requirements for the nonlinearity correction system are formulated. The effect of the 4-th order resonances caused by the correcting octupoles is estimated

1984-01-01

113

Octupole collectivity in 98,100,102Mo  

International Nuclear Information System (INIS)

Excited states in 98,100,102Mo have been studied via the 30Si+168Er-induced fission reaction at a beam energy of 142 MeV. Prompt ? rays were detected with the EUROBALL III multidetector array. The level schemes are extended with more than 20 new transitions and interpreted in the framework of a soft-octupole vibration model

2007-01-01

114

Cryogenically cooled octupole ion trap for spectroscopy of biomolecular ions  

Science.gov (United States)

We present here the design of a linear octupole ion trap, suitable for collisional cryogenic cooling and spectroscopy of large ions. The performance of this trap has been assessed using ultraviolet (UV) photofragmentation spectroscopy of protonated dipeptides. At the trap temperature of 6.1 K, the vibrational temperature of the ions reaches 9.1 K, although their estimated translational temperature is ˜150 K. This observation suggests that, despite the significant translational heating by radio-frequency electrical field, vibrational cooling of heavy ions in the octupole is at least as efficient as in the 22-pole ion traps previously used in our laboratory. In contrast to the 22-pole traps, excellent radial confinement of ions in the octupole makes it convenient for laser spectroscopy and boosts the dissociation yield of the stored ions to 30%. Overlap of the entire ion cloud by the laser beam in the octupole also allows for efficient UV depletion spectroscopy of ion-He clusters. The measured electronic spectra of the dipeptides and the clusters differ drastically, complicating a use of UV tagging spectroscopy for structural determination of large species.

Boyarkin, Oleg V.; Kopysov, Vladimir

2014-03-01

115

On the asymptotic selection rules for octupole operators  

Energy Technology Data Exchange (ETDEWEB)

The selection rules and the values of the matrix elements of the octupole operators r'{sup 3}Y{sub 3{mu}} in the cylindrical basis vertical strokeNN{sub z}{Lambda}> are tabulated. Their applicability to 'normal-' and 'superdeformed' nuclei is discussed. (orig.).

Piepenbring, R. (Inst. des Sciences Nucleaires, 38 - Grenoble (France))

1992-05-04

116

Effect of deformation rate on the mechanical properties of arteries  

Directory of Open Access Journals (Sweden)

Full Text Available Pig aorta samples were tested uniaxially and equi- biaxially at deformation rates from 10 to 200 %/s. Under uniaxial and biaxial testing, loading forces were reduced up to 20% when the deformation rate was increased from 10 to 200 %/s, which is the opp- osite to the behaviour seen in other biological tissues. A rate-dependent isotropic hyperelastic constitutive equation, derived from the Mooney-Rivlin model, was fitted to the experimental results (e.g. aorta specimens using an inverse finite element technique. In the proposed model, one of the material par- ameters is a linear function of the deformation rate. The inverse relationship between stiffness and defo- rmation rate raises doubts on the hypothesized rel- ationship between intramural stress, arterial injury, and restenosis.

Savvas G. Hatzikiriakos

2010-03-01

117

Luminescence properties of deformed CaO crystals  

Energy Technology Data Exchange (ETDEWEB)

In deformed CaO crystals, the predominant optical-absorption band at 270 nm and the corresponding luminescence band at 450 nm have been investigated. The absorption coefficient increases linearly with deformation up to [similar to]5% whereas the luminescence intensity saturates earlier. Thermal annealing indicates that appreciable decrease in the absorption begins at [similar to]600 K. In contrast, the luminescence intensity diminishes very rapidly at temperatures not much above room temperature. Time-resolved luminescence indicates that the 450-nm band is composed of two bands: a 475-nm band with lifetimes of [lt]3 ns and [similar to]10 [mu]s, and a 440-nm band with a lifetime of [similar to]1 ms at room temperature. In a test for laser action no optical gain was observed in a deformed CaO crystal.

Gonzalez, R. (Departamento de Ingenieria, Escuela Politecnica Superior, Universidad Carlos III, 28913 Leganes Madrid (Spain) Solid State Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6031 (United States)); Chen, Y.; Ballesteros, C. (Solid State Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6031 (United States)); Liu, H.; Williams, G.P. Jr.; Rosenblatt, G.H.; Williams, R.T. (Department of Physics, Wake Forest University, Winston-Salem, North Carolina 27109 (United States)); Gellermann, W. (Department of Physics, University of Utah, Salt Lake City, Utah 84112 (United States))

1993-03-01

118

Luminescence properties of deformed CaO crystals  

Science.gov (United States)

In deformed CaO crystals, the predominant optical-absorption band at 270 nm and the corresponding luminescence band at 450 nm have been investigated. The absorption coefficient increases linearly with deformation up to ~5% whereas the luminescence intensity saturates earlier. Thermal annealing indicates that appreciable decrease in the absorption begins at ~600 K. In contrast, the luminescence intensity diminishes very rapidly at temperatures not much above room temperature. Time-resolved luminescence indicates that the 450-nm band is composed of two bands: a 475-nm band with lifetimes of <3 ns and ~10 ?s, and a 440-nm band with a lifetime of ~1 ms at room temperature. In a test for laser action no optical gain was observed in a deformed CaO crystal.

Gonzalez, R.; Chen, Y.; Ballesteros, C.; Liu, Hanli; Williams, G. P., Jr.; Rosenblatt, G. H.; Williams, R. T.; Gellermann, W.

1993-03-01

119

String field theory. Algebraic structure, deformation properties and superstrings  

Energy Technology Data Exchange (ETDEWEB)

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

Muenster, Korbinian

2013-07-23

120

String field theory. Algebraic structure, deformation properties and superstrings  

International Nuclear Information System (INIS)

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

2013-01-01

 
 
 
 
121

Contrasting behaviour of octupole bands at high spin in 220Ra and 222Th and lifetimes of states in the opposite-parity bands of 153Eu  

International Nuclear Information System (INIS)

The well-established octupole bands in 220Ra and 222Th have been studied to high spins, using the Eurogram gamma-ray spectrometer. The nuclei were produced in the reaction 208Pb(18O, ?2n/4n). The yrast octupole bands have been observed up to 31 ? in 220Ra and 25? in 222Th, but the gamma-ray multiplicities have been measured to be very nearly the same. This observation is interpreted as evidence for the crossing of the octupole band by a four quasi-particle aligned band in 222Th, which has been predicted by cranked HFB calculations. Values of intrinsic electric dipole moments have been inferred from B(E1)/B(E2) ratios, and are found to be 0.34(4) efm for 220Ra and 0.55(3) efm for 222Th. These observations are consistent with the interpretation of the structure of these nuclei in terms of octupole deformation. (Author)

1995-01-01

122

Fission fragment formation and fission yields in the model of octupole neutron-proton oscillations  

Directory of Open Access Journals (Sweden)

Full Text Available The fission fragment formation is considered as a result of neck instability in the process of octupole oscillations of neutrons and protons near the scission point. To describe such a phenomenon the potential surface of fissionning nucleus with neck radius about 1 fm was calculated with shell correction approach. The new version of smooth liquid drop part of deformation energy is proposed. The liquid drop part is formulated in a double folding model with n-n, p-p, and n-p Yukawa interaction potential. Fission fragment mass and charge distributions correspond approximately to isoscalar and isovector modes of vibrations and are defined by wave functions of oscillations. The preliminary calculation results have shown a rather good description of main integral fission yield observables.

Yavshits S.

2010-03-01

123

Interplay between octupole and quasiparticle excitations in 178Hg and 180Hg  

International Nuclear Information System (INIS)

Excited structures in the Z=80, 178Hg (N=98), and 180Hg (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

2000-10-01

124

Octupole correlations in the structure of 02+ bands in the N=88 nuclei 150Sm and 152Gd  

Science.gov (United States)

Knowledge of the exact microscopic structure of the 01+ ground state and first excited 02+ state in 150Sm is required to understand the branching of double ? decay to these states from 150Nd. The detailed spectroscopy of 150Sm and 152Gd has been studied using (?,xn) reactions and the ?-ray arrays AFRODITE and JUROGAM II. Consistently strong E1 transitions are observed between the excited K? = 02+ bands and the lowest negative parity bands in both nuclei. These results are discussed in terms of the possible permanent octupole deformation in the first excited K? = 02+ band and also in terms of the “tidal wave” model of Frauendorf.

Bvumbi, S. P.; Sharpey-Schafer, J. F.; Jones, P. M.; Mullins, S. M.; Nyakó, B. M.; Juhász, K.; Bark, R. A.; Bianco, L.; Cullen, D. M.; Curien, D.; Garrett, P. E.; Greenlees, P. T.; Hirvonen, J.; Jakobsson, U.; Kau, J.; Komati, F.; Julin, R.; Juutinen, S.; Ketelhut, S.; Korichi, A.; Lawrie, E. A.; Lawrie, J. J.; Leino, M.; Madiba, T. E.; Majola, S. N. T.; Maine, P.; Minkova, A.; Ncapayi, N. J.; Nieminen, P.; Peura, P.; Rahkila, P.; Riedinger, L. L.; Ruotsalainen, P.; Saren, J.; Scholey, C.; Sorri, J.; Stolze, S.; Timar, J.; Uusitalo, J.; Vymers, P. A.

2013-04-01

125

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

126

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

2012-02-01

127

Influence of deformation temperature on the structure and mechanical properties of tungsten base alloys  

International Nuclear Information System (INIS)

Low-alloyed tungsten alloys were obtained by melting with subsequent thermomechanical treatment under different conditions. The structure and substructure were studied by optical and electron microscopy methods. The width of X-ray diffraction lines was also determined to characterize microdistortions of the crystal lattice. The strength properties, plastic characteristics and ductile brittle transition temperature were determined in a 100-600 deg C temperature range under mechanical tensile tests. It is shown that in a high-deformed metal (degree of reduction approximately equal to 80% and more) the dislocation cell size governs some mechanical properties as well as the grain size determines there properties in a recrystallized state. It is shown that the structure parameters and mechanical properties of different tungsten alloys vary in dependence on t (deformation) in a similar way. The investigation also shows that the dispersed particle presence in a deformed tungsten alloy induces an indirect rather than direct strengthening

1981-01-01

128

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 properties of platinum. The Vickers hardness (HV values were determined with different deformation degree, starting from annealing temperatures for platinum of different purity and tensile strength (Rm, flow limit (Rp0,2 and elongation (A in the function of annealing temperatures and annealing time at a constant deformation degree.

Trumi? B.

2010-01-01

129

Micromechanical deformations in PP/lignocellulosic filler composites: Effect of matrix properties  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Polypropylene composites were prepared from three different PP matrices, a homopolymer, a random and a heterophase copolymer, and corn cob to study the effect of matrix characteristics on deformation and failure. The components were homogenized in an internal mixer and compression molded to 1 mm thick plates. Mechanical properties were characterized by tensile testing, while micromechanical deformations by acoustic emission measurements and fractography. The results proved that the dominating...

2010-01-01

130

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

International Nuclear Information System (INIS)

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

1986-11-01

131

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 pres...

Kommel, Lembit; Saarna, Mart; Traksmaa, Rainer; Kommel, Igor

2012-01-01

132

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

International Nuclear Information System (INIS)

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

1982-01-01

133

Determination of the deformation properties of Søvind Marl  

DEFF Research Database (Denmark)

A serie of tests were made to determine the preconsolidation stresses, Ï?â?²pc, and the consolidation modulus, K, of Søvind Marl, a fissured plastic tertiary clay. The fissures causes a decrease in the stiffness of the Søvind Marl, which can be mistaken for the decrease that happens when the effective stresses in the soil, Ï?â?², passes Ï?â?²pc. The effects of the fissures are assessed, and an estimate of the stress level at which they will compress are made. During the consolidation tests, the effective stress level is raised to more then 24,000 kPa to get a comprehensive description of the preconsolidation of the soil. It is important to know how a strongly preconsolidated soil will deform when reloaded. The deformation parameters of the strongly preconlidated Søvind Marl is determined by unloading/reloading testing. It is found that the stiffness of the Søvind Marl depends of the plasticity index, and one conclusive expression of the consolidation modulus of the Søvind Marl can therefor not be given.

Grønbech, Gitte; Nielsen, Benjaminn Nordahl

2010-01-01

134

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

International Nuclear Information System (INIS)

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.

2010-09-06

135

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

CERN Multimedia

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

136

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2007-01-01

137

Octupole correlations in the odd-Z nuclei 148-151Eu  

International Nuclear Information System (INIS)

The effects of octupole correlations in the Z=63 nuclei 148-151Eu are studied. The persistency of octupole instability through the transitional region of near-spherical (N?85) towards prolate nuclei (N?88) is established and discussed. Intrinsic dipole moments, which are experimentally inferred from the measured electric dipole transition rates observed between parity doublets, are used to characterize the strength of the octupole correlations

1994-12-01

138

Structure property correlation: electrochemomechanical deformation in polypyrrole films  

International Nuclear Information System (INIS)

Direct electrochemomechanical deformation (ECMD) behavior in the electrodeposited freestanding films of polypyrrole (PPy) doped with naphthalene sulphonic acid (NSA) has been investigated using cyclic voltammetry and cyclic step-voltammetry. It has been found that NSA doped PPy exhibits different film morphology when it was electrodeposited on to the different substrates such as non-corrosive stainless steel, indium-tin-oxide glass and platinum being used as anode. The differential behavior in ECMD characteristics observed on PPy film deposited on different substrates are associated with differential microstructures and porosities of the film as evidenced by scanning electron microscopic observations. An attempt has been made to correlate the effect of film morphology and the relative porosity of the film on the ECMD characteristics in the NSA doped PPy freestanding films

2003-08-22

139

Structure property correlation: electrochemomechanical deformation in polypyrrole films  

Energy Technology Data Exchange (ETDEWEB)

Direct electrochemomechanical deformation (ECMD) behavior in the electrodeposited freestanding films of polypyrrole (PPy) doped with naphthalene sulphonic acid (NSA) has been investigated using cyclic voltammetry and cyclic step-voltammetry. It has been found that NSA doped PPy exhibits different film morphology when it was electrodeposited on to the different substrates such as non-corrosive stainless steel, indium-tin-oxide glass and platinum being used as anode. The differential behavior in ECMD characteristics observed on PPy film deposited on different substrates are associated with differential microstructures and porosities of the film as evidenced by scanning electron microscopic observations. An attempt has been made to correlate the effect of film morphology and the relative porosity of the film on the ECMD characteristics in the NSA doped PPy freestanding films.

Pandey, Shyam S.; Takashima, Wataru; Kaneto, Keiichi

2003-08-22

140

Tests of octupole band structures using proton scattering and gamma-ray spectroscopy  

International Nuclear Information System (INIS)

In many even-even nuclei, bands of negative parity states have been interpreted as open-quotes octupole bandsclose quotes, which are sequences of vibrational or rotational excitations coupled to a low energy octupole phonon. Careful experimental examination of these structures is of interest because octupole phonons are generally considered to be unstable at high angular momentum. Results from experimental studies of octupole band structures in three nuclei are presented. Two of these nuclei, 144,146Nd, have been studied via inelastic scattering of 35 MeV protons. The third nucleus, 74Se, has been examined using the techniques of high spin gamma-ray spectroscopy

1992-08-23

 
 
 
 
141

Large-Deformation Properties of Wheat Flour and Gluten Dough  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Keywords: Wheat, gluten protein, bread, puff pastry, flour dough, gluten dough,rheology,uniaxialextension, biaxial extension, fracture.Rheologicaland fracture properties of flour and glutendoughsfrom eight wheat cultivars were studied and related to ...

Sliwinski, E. L.

2003-01-01

142

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

143

Mechanical properties and deformation of polycrystalline lithium orthosilicate  

Energy Technology Data Exchange (ETDEWEB)

Room-temperature strength, fracture toughness, Young's modulus, and thermal-shock resistance were determined for 68--98% dense lithium orthosilicate (Li/sub 4/SiO/sub 4/) 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 Li/sub 4/SiO/sub 4/ fractures at T less than or equal to 800/degree/C before reaching steady state and deforms plastically at 900/degree/C. It is more creep-resistant at 900/degree/C than Li/sub 2/O, about equal to Li/sub 2/Zr)/sub 3/, and less than LiA10/sub 2/. 13 refs., 4 figs., 1 tab.

Bar, K.; Chu, C.Y.; Singh, J.P.; Goretta, K.C.; Routbort, J.L.; Billone, M.C.; Poeppel, R.B.

1988-02-01

144

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

1988-04-10

145

Surrounding rock deformation properties and determination of support parameters of soft rock roadway in deep mine  

Energy Technology Data Exchange (ETDEWEB)

Based on laboratory tests of the main physical and mechanical properties and the measured results of the deformation of the rock surrounding the roadway in Maluping Mine the deformation and destruction properties of the surrounding rock in the deep soft rock roadway were discussed. Through numerical modelling with FLAC{sup 3D} the ranges of the fragmentation area and the plastic area, the stress distribution and strains of the surrounding rock around the roadway in the original support were analyzed. The support parameters of a new scheme were optimised by numerical modelling. The second support time was determined. The proposition that tube-like bolt can be substituted for short bolt or rivet and corner bolt reinforcement was put forward. Industrial test results show that good effects to control the deformation of the surrounding rock in deep roadways are obtained with the proposed scheme. 11 refs., 3 figs., 3 tabs.

Wang Qi-sheng; Li Xi-bing; Li Di-yuan [Central South University, Changsha (China). College of Resources and Safety Engineering

2008-04-15

146

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.

Jurica Sori?

2013-09-01

147

Self-similarity properties of nafionized and filtered water and deformed coherent states  

CERN Multimedia

By resorting to measurements of physically characterizing observables of water samples perturbed by the presence of Nafion and by iterative filtration processes, we discuss their scale free, self-similar fractal properties. By use of algebraic methods the isomorphism is proved between such self-similarity features and the deformed coherent state formalism.

Capolupo, A; Elia, V; Germano, R; Napoli, E; Niccoli, M; Tedeschi, A; Vitiello, G

2013-01-01

148

Self-Similarity Properties of Nafionized and Filtered Water and Deformed Coherent States  

Science.gov (United States)

By resorting to measurements of physically characterizing observables of water samples perturbed by the presence of Nafion and by iterative filtration processes, we discuss their scale free, self-similar fractal properties. By use of algebraic methods, the isomorphism is proved between such self-similarity features and the deformed coherent state formalism.

Capolupo, A.; Del Giudice, E.; Elia, V.; Germano, R.; Napoli, E.; Niccoli, M.; Tedeschi, A.; Vitiello, G.

2014-11-01

149

Effect of deformation in superplastic state on structure and properties of MA21 alloy  

International Nuclear Information System (INIS)

Effect of superplastic deformation on the structure and properties of the MA21 magnesium-lithium alloy is investigated. It is shown that the alloy treatment under conditions of superplasticity permits to increase the alloy strength properties by 30-40 MPa as compared with the properties obtained after the treatment according to the standard regime and by approximately 20MPa as compared with the properties of the alloy, subjected to strengthening heat treatment (tempering from 350 deg C and natural ageing). Using the microroentgenospectral analysis of the alloy and investigation of thin foils it is established that formation in the deformation process of a state of high structural and chemical homogeneity of the alloy is a characteristic feature of the treatment under conditions of superconductivity

1981-01-01

150

Large-deformation properties of wheat dough in uni- and biaxial extension. Part I. Flour dough  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Rheological and fracture properties of optimally mixed flour doughs from three wheat cultivars which perform differently in cereal products were studied in uniaxial and biaxial extension. Doughs were also tested in small angle sinusoidal oscillation. In accordance with previously published results the linear region was found to be very small. The rheological properties at small deformations hardly depended on the cultivar. A higher water content of the dough resulted in a lower value for the ...

Sliwinski, E. L.; Kolster, P.; Vliet, T.

2004-01-01

151

Large-deformation properties of wheat dough in uni- and biaxial extension. Part II. Gluten dough  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Glutens were isolated from flour of three European wheat cultivars which perform differently in cereal products. The rheological and fracture properties of gluten-water doughs were determined in uniaxial and biaxial extension at large deformations and small angle sinusoidal oscillation tests and compared with the mechanical properties of the parental flour doughs. At 25 °C the linear region was in the same range as that of flour dough, while at a higher temperature (45 °C) the linear region...

Sliwinski, E. L.; Hoef, M.; Kolster, P.; Vliet, T.

2004-01-01

152

Homogenized Elastic Properties of Graphene for Small Deformations  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2013-01-01

153

Using Octupoles for Background Control in Linear Colliders an Exploratory Conceptual Study  

CERN Document Server

If one adds a suited Octupole (or an even higher multipole) lattice to linear collider Quadrupole FODO lattices, the amplifying properties of the combined lattice drive particles in the tails, but not those in the core, into resonant losses. This approach is quite different in concept and beam dynamics impact from past proposed use of non-linear elements for collimation. This non-traditional scheme for background control has the added advantage that most, or maybe all, of the Halo collimation can be done using the lever arm of the real estate of the main accelerators, thus reducing the costly length of a separate dedicated collimation section and also unifying machine protection and background control. Simulations of particle distributions are presented. This approach requires co operation by the designers of the accelerators, the beam delivery system, and the Detector, because a careful balance between sometimes conflicting requirements has to be found. As a second component of this approach the use of Octup...

Pitthan, R

1999-01-01

154

High. beta. studies in the Wisconsin Toroidal Octupole  

Energy Technology Data Exchange (ETDEWEB)

A wide range of MHD stable high ..beta.. plasmas is produced in the Wisconsin Levitated Octupole. At or near the single fluid regime we obtain, in the bad curvature region, ..beta.. = nk(T/sub e/ + T/sub i/)8..pi../B/sup 2/ approx. = 8%, twice the theoretical single fluid ballooning instability limit of 4%. We also obtain stable plasmas at ..beta.. approx. = 35%, 9 times the theoretical limit, in a regime in which both finite ion gyroradius and gyroviscosity effects are important.

Halle, J. H.; Kellman, A.; Post, R. S.; Prager, S. C.; Strait, E. J.; Zarnstorff, M. C.

1980-09-01

155

Magnetic octupole strength in rare-earth nuclei: A sum-rule approach  

International Nuclear Information System (INIS)

We use linear energy-weighted sum rules within the proton-neutron interacting boson model to deduce a relationship between magnetic dipole and magnetic octupole transition probabilities. We then obtain a first estimate of the summed magnetic octupole strength to be expected in rare-earth nuclei

1995-06-01

156

Mechanical properties and microstructure of resistance spot welded severely deformed low carbon steel  

International Nuclear Information System (INIS)

Highlights: ? Resistance spot welding is successfully used for severely deformed steel sheet. ? Microstructures of FZ and HAZ are refined to lower sizes at higher pass number. ? Mechanical properties in FZ and HAZ are increased with increasing the pass number. ? Electrode dip and nugget diameter are increased with increasing the pass number. - Abstract: The welding of nanostructured low carbon steel sheets produced by severe plastic deformation (SPD) has been considered in the present paper. Constrained groove pressing (CGP) method is used for imposing the severe plastic deformation to the steel sheets as a large pre-strain. The SPDed sheets are joined using resistance spot welding (RSW) process. The results show that severe plastic deformation can effectively increase the electrical resistivity of steel sheets; therefore it can affect the microstructure and mechanical properties of spot welds. Microstructure and mechanical properties of fusion zone, heat affected zone (HAZ), recrystallized zone and base metal of SPDed sheets are investigated and the results are compared with those of as-received specimens. The results show that with increasing the large pre-strain in sheets, at constant welding parameters (welding current and time), the fusion zone size, electrode indentation and nugget diameter are increased. Thus, peak load and hardness in fusion zone and HAZ are increased with increasing the CGP pass number. Also, the microstructures of fusion zone and HAZ are refined to lower sizes for larger pre-strained specimens.

2011-11-25

157

Two-phonon octupole excitations and the role of E1 transitions from ocutpole states  

International Nuclear Information System (INIS)

With the inelastic neutron scattering (INS) reaction, low-lying octupole states are populated in a statistical manner, and recent advances in INS-DSAM measurements following the (n,n'?) reaction have made it possible to determine nuclear lifetimes in the femtosecond regime in heavy nuclei. In two mass regions, the authors have measured the lifetimes of a number of dipole transitions and have observed fast E1 transitions which can be interpreted as evidence for octupole-octupole and quadrupole-octupole excitations. They find, however, that the occurrence of fast E1 transitions is a more common phenomenon than expected and are forced to question whether such transitions can unambiguously be taken as evidence of collective octupole character

1992-08-23

158

Octupole Ordering Model for the Phase IV of CexLa1-xB6  

CERN Multimedia

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

Kubo, K; Kubo, Katsunori; Kuramoto, Yoshio

2003-01-01

159

Structure and mechanical properties of austenitic steel during linear and plane-strain low temperature deformation  

International Nuclear Information System (INIS)

The structure and the properties of Kh18N10T steel depending on the kind of the stressed state during the low-temperature straining (at -160 deg C) were examined. It has been established that the intensity of the development of martensite transformation depends on the method of straining. When the linear stress passes over to the flat or plane stress, the resistance of steel to the plastic deformation increases. An analytical expression has been derived for the stress diagram for the strain hardening of austenite and for the resistance to deformation of the forming martensite. In the case of biaxial stretching, the martensite transformation is braked, the parameters of the deformation diagram vary, and the plasticity is decreased

1978-01-01

160

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

International Nuclear Information System (INIS)

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. 10 percent cold-working hardening established to increase lona-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 it's descending branch shift in the direction of shorter durabilities in comparison with the deformed state. Post-deformation tempering approximates the metal properties to original level

1983-01-01

 
 
 
 
161

Optical properties of two-dimensional polymer photonic crystals after deformation-induced pattern transformations  

Science.gov (United States)

The photonic band structure and optical transmittance of two-dimensional periodic elastomeric photonic crystals are studied computationally to understand the effects of large strains on optical properties of the structures. The large compressive deformation patterns of the two-dimensional periodic structure studied by Mullin and coworkers [Mullin, T., Deschanel, S., Bertoldi, K., Boyce, M.C., 2007. Pattern transformation triggered by deformation. Physical Review Letters 99(8), 084301] are first reproduced using hyperelastic material models for the elastomer SU-8. Finite element analysis is then used to solve Maxwell's equations to obtain light transmittance through both the undeformed and deformed structures; simultaneously the wave equation resulting from the appropriate two-dimensional form of Maxwell's equations is solved as an eigenvalue problem to obtain the band structure. The deformation-induced shift in transmission spectrum valleys for different bands is calculated, and the changes in the width of these reflectance peaks are also obtained. The band structure calculation shows that there are no complete photonic band gaps as expected for the low dielectric contrast system. However, the effect of the observed reversible, symmetry-breaking deformation pattern is to uncouple many of the photonic bands in all three high symmetry directions, i.e. ?-X, X-M, and ?-M. New non-degenerate deformation-induced optical modes appear in both the real space transmittance spectra and the band structure with lower reflectance values. Analyses of the deformation pattern, the optical mode shapes, and the photonic band structure reveal that localized regions of large rotation are responsible for the significant changes in optical transmittance. The results have practical importance for the design of strain-tunable optomechanical materials for sensing and actuation.

Krishnan, D.; Johnson, H. T.

2009-09-01

162

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

Mart SAARNA

2012-12-01

163

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.

2013-07-01

164

34?s isomer at high spin in 212Fr: evidence for a many particle octupole coupled state  

International Nuclear Information System (INIS)

A very high spin isomeric state with ?m = 34(3)?s has been observed at an excitation energy of 8.5 MeV in 212Fr. The experimental evidence favours an E3 assignment, with a very large E3 transition strength, B(E3) = 100 (12) x 103 e2fm6, to one of the ?-rays de-exciting the isomer. The observed properties are in very good agreement with the characteristics of a 34+ state predicted by the multiparticle octupole vibration model. 10 refs., 1 tab., 3 figs

1990-01-01

165

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

Energy Technology Data Exchange (ETDEWEB)

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

Tobe, H. [Division of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan); Kim, H.Y., E-mail: heeykim@ims.tsukuba.ac.jp [Division of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan); Inamura, T.; Hosoda, H. [Precision and Intelligence Laboratory, Tokyo Institute of Technology, Yokohama 226-8503 (Japan); Nam, T.H. [School of Materials Science and Engineering and ERI, Gyeongsang National University, 900 Gazwadong, Jinju, Gyeongnam 660-701 (Korea, Republic of); Miyazaki, S., E-mail: miyazaki@ims.tsukuba.ac.jp [Division of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan); School of Materials Science and Engineering and ERI, Gyeongsang National University, 900 Gazwadong, Jinju, Gyeongnam 660-701 (Korea, Republic of); Center of Excellence for Advanced Materials Research, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia)

2013-11-15

166

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

International Nuclear Information System (INIS)

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

2013-11-15

167

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

Energy Technology Data Exchange (ETDEWEB)

Highlights: Black-Right-Pointing-Pointer We fabricated a 310 type ODS austenitic steel by the process of MA and HIP. Black-Right-Pointing-Pointer Plastic deformations, including forging and hot rolling, were applied to samples. Black-Right-Pointing-Pointer Fine Y-Ti-O particles dispersed in a relatively uniform way after forging. Black-Right-Pointing-Pointer Ductility increased greatly after deformations, while strength decreased slightly. - Abstract: ODS-310 austenitic steel (Fe-25Cr-20Ni-0.35Y{sub 2}O{sub 3}-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 Degree-Sign C and 700 Degree-Sign 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 Degree-Sign C. Elongation increased two times after plastic deformations while there was only slight decrease in strength properties.

Wang Man [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 10083 (China); Zhou Zhangjian, E-mail: zhouzhj@mater.ustb.edu.cn [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 10083 (China); Sun Hongying; Hu Helong; Li Shaofu [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 10083 (China)

2012-11-15

168

Effect of Deformation Temperature on Texture and Thermoelectric Properties of Bi0.5Sb1.5Te3 Prepared by Hot-Press Deformation  

Science.gov (United States)

The effects of deformation temperature on texture and thermoelectric properties of p-type Bi0.5Sb1.5Te3 sintered materials were investigated. The sintered materials were prepared by mechanical alloying and hot-press sintering. The hot-press deformation was performed at 723 K and 823 K by applying mechanical pressure in a graphite die. Then, the materials were extruded in the direction opposite to the direction of applied pressure. X-ray diffraction and electron backscattered diffraction patterns showed that the hexagonal c-plane tended to align along the extruded direction when the samples were deformed at high temperatures. The thermoelectric power factor was increased by high-temperature hot-press deformation because of the low electrical resistivity that originated from the c-plane orientation.

Kitagawa, H.; Kurata, A.; Araki, H.; Morito, S.; Tanabe, E.

2010-09-01

169

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

2011-07-01

170

Can radial gradients of swelling and of mechanical properties create extra deformation of fast fuel elements  

International Nuclear Information System (INIS)

The temperature gradient inside the cladding causes swelling gradients and irradiation creep modulus gradient at a temperature higher than 500"0C (at least for steel 316). Swelling contribution to an increase in cladding length and diameter are equal to the mean swelling, if variations of mechanical properties with temperature are neglected. If mechanical property gradient are taken into account the solution of the problem is obtained by a classical analytic calculation with hypothesis on one dimension deformations and constant stress. In this case swelling contribution is different to the mean swelling. An additional term can be evaluated with the following assumptions: the tube is thin and swelling gradient and irradiation creep are constant, as but extra deformations are low

1981-08-21

171

Change in the deformation and strength properties of coal during interaction with surfactant solutions  

Energy Technology Data Exchange (ETDEWEB)

Features of the change in strength and deformation properties of coal during the action of adsorption-active media, especially under the conditions of a complex stress state, are not always evident and, consequently, cannot be taken adequately into account when performing work utilizing the physicochemical treatment of rock masses and coal in order to increase the safety and efficiency of mining production processes. Taking into account the importance of such data for intensification of the change in properties and state of the host rock during mining, including even finding the optimal conditions for coal destruction, they studied the singularities of adsorption-active fluid interaction with coal under complex stress state conditions. The deformation curves for brown coal and coal of grade T obtained under simple uniaxial compression conditions are represented.

Voronkov, G.Ya.; Martsinkevich, G.I.

1987-07-01

172

Electrical textile sensors for repeated large deformation: structures and electromechanical properties  

Science.gov (United States)

This paper presents a systematic study of various fibrous structures that exhibit excellent strain/force sensing properties for repeated large deformation (up to 50% or more). The multiple-scaled investigation has been conducted with fibers, yarns and fabrics made from intrinsic electrically conductive materials or coated with conductive polymers or composites. The structures and electrical conductivity of these fibrous assemblies during large deformation have been characterized by various experimental techniques. Several challenges of using textiles as strain sensors and solutions to various problems are discussed. A theoretical analysis of knitted fabric strain sensors is presented to link the fiber properties and fabric structure with the electrical conductivity of the sensors as a function of strain/force.

Tao, Xiaoming

2008-11-01

173

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, material properties and deformation of an object grasped by a robot gripper. To estimate the parameters we minimize an error function incorporating visual and physical correctness. Through simulated and real-world experiments we demonstrate that we are able to find 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

2012-01-01

174

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 temper...

Langdon, T. G.

2008-01-01

175

Variation of hydraulic properties on sedimentary rock due to shear deformation  

International Nuclear Information System (INIS)

In order to investigate the variation of hydraulic properties on soft rock due to shear deformation, permeability tests were performed on hard shale of the Wakkanai formation by axial flow and radial flow techniques under triaxial compression. The experimental results showed that the axial direction permeability increased to approximately 10 times larger than the initial one in residual strength zone. On the other hand, the radial direction permeability increased remarkably in strain softening zone. (author)

2011-01-01

176

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

Science.gov (United States)

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

Reed, R. P.

1972-01-01

177

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

1999-11-01

178

Structure and mechanical properties of maraging steel after plastic deformation and impact loading  

International Nuclear Information System (INIS)

The methods of diffraction electron microscopy X-ray diffraction analysis, measuring of magnetic and mechanical properties have been used to investigate the structure, mechanism and kinetics of phase transformations in N12K7M5TYu high-strength maraging steel strengthened by plastic deformation in austenitic or martencitic states by martencite treatment with shock waves as well as by ageing. The causes of intensifying influence of considered external effects on the structure, ageing processes, and respectively, mechanical properties in the steel are discussed

1981-03-01

179

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

International Nuclear Information System (INIS)

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)

1992-01-01

180

Spin assignment of the lowest octupole bandhead in _2_3_6U  

International Nuclear Information System (INIS)

Measurements carried out to determine the nature of the octupole bandhead in _2_3_6U led in the past to considerable confusion concerning its spin assignment. To see whether penetration effects are important in the conversion electron decay of the octupole band, a high resolution measurement was carried out at the #betta#-spectrometer of the ILL. Relative intensities have been determined for the transitions from the octupole bandhead to the O"+, 2"+ and 4"+ members of the ground state rotational. (U.K.)

1981-09-11

 
 
 
 
181

Two-octupole-phonon states in {sup 146,148}Gd  

Energy Technology Data Exchange (ETDEWEB)

Recently the multi-octupole-phonon states have been observed in {sup 146,148}Gd and the relevant B(E3) values have been measured. We give a report of our microscopic calculations on the collective multi-octupole-phonon-excited states in these nuclei by using the Dyson boson mapping method. It has been clarified that not only the strong collectivity in the octupole modes in these nuclei but also the coupling with the single-particle modes work together to bring about the highly enhanced B(E3) values in {sup 148}Gd. (author).

Takada, Kenjiro; Shimizu, Y.R. [Kyushu Univ., Fukuoka (Japan). Dept. of Physics

1995-03-01

182

Plasma resistivity measurements in the Wisconsin levitated octupole  

International Nuclear Information System (INIS)

Resistivity measurements parallel to the magnetic field were made on gun injected plasmas ranging in density from 10"9cm"-"3 to 10"1parallelcm"-"3 in the Wisconsin levitated octupole with toroidal and poloidal magnetic fields. The 10"9cm"-"3 plasma was collisionless with lambda/sub mfp/ > 100 mirror lengths, had T/sub e/ = 10 eV, T/sub i/ = 30 eV and was found to have anomalous resistivity scaling like eta = ?T/sub e//n/sub e/ when E/sub parallel/ > E/su c/ is the Dreicer critical field. The 10"1"2cm"-"3 plasma was collisional with lambda/sub mfp/ < mirror length, had T/sub e/ = T/sub i/ approx. = .2 eV and was found to have Spitzer resistivity when E/sub parallel/ < E/sub c/

1980-01-01

183

Plasma resistivity measurements in the Wisconsin levitated octupole  

Energy Technology Data Exchange (ETDEWEB)

Resistivity measurements parallel to the magnetic field were made on gun injected plasmas ranging in density from 10/sup 9/cm/sup -3/ to 10/sup 1/parallelcm/sup -3/ in the Wisconsin levitated octupole with toroidal and poloidal magnetic fields. The 10/sup 9/cm/sup -3/ plasma was collisionless with lambda/sub mfp/ > 100 mirror lengths, had T/sub e/ = 10 eV, T/sub i/ = 30 eV and was found to have anomalous resistivity scaling like eta = ..sqrt..T/sub e//n/sub e/ when E/sub parallel/ > E/su c/ is the Dreicer critical field. The 10/sup 12/cm/sup -3/ plasma was collisional with lambda/sub mfp/ < mirror length, had T/sub e/ = T/sub i/ approx. = .2 eV and was found to have Spitzer resistivity when E/sub parallel/ < E/sub c/.

Brouchous, D. A.

1980-11-01

184

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

185

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

CERN Document Server

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

Mortazavi, M

2012-01-01

186

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

187

An unusual route to develop poly(lactic acid) based materials with deformation-recovery properties  

Science.gov (United States)

A novel method based on co-crystallizing polymer blends was developed to obtain Poly(lactic acid) (PLA) based materials with deformation recovery properties. Two sets of blends were studied. One based on the PDLA-soft polymer-PDLA triblock copolymer and PLLA, where D and L refer to the two chiral isomers of PLA, while the other was based on homopolymer blends of PDLA/soft polymer/PLLA having identical chemical composition. The mechanical properties and morphological features of the two sets of blends were completely different. The triblock copolymer/ PLLA blends gave rise to flexible, tough semicrystalline materials while the corresponding homopolymer blends exhibited very low strains at break and high dissipative/dampening properties. The drastically different stereocomplex crystallization kinetics in the two sets of blends led to interspherulitic segregation of the amorphous chains in the triblock blends while intraspherulitic segregation occurred in the homopolymer blends. The presence of significant connectivity between the stereocomplex crystallites formed, in the triblock copolymer/ PLLA blends, was important for the deformation shape recovery characteristics observed. In addition, it was found that the use of ether-ester based plasticizers significantly reduced the glass transition temperature and enhanced the recovery property of the triblock copolymer based PLA blends.

Rathi, Sahas; Ng, David; Coughlin, E. Bryan; Hsu, Shaw; Golub, Charles; Ling, Gerald; Tzivanis, Mike

2013-03-01

188

Optimisation by plastic deformation of structural and mechanical uranium alloys properties  

International Nuclear Information System (INIS)

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

189

Electric octupole contribution to the angular distribution of the krypton 4p photoelectrons  

Science.gov (United States)

The angular distribution of Kr 4p photoelectrons was measured with linearly polarized synchrotron radiation in the function of the photon energy. The shape of the measured angular distributions indicates the presence of octupol interaction.

Holste, K.; Borovik, A. A., Jr.; Buhr, T.; Ricz, S.; Kövér, Á.; Bernhardt, D.; Schippers, S.; Varga, D.; Müller, A.

2014-04-01

190

Measurements of low energy hydrogen ion effective sticking coefficients on titanium in the Wisconsin Levitated Octupole  

Energy Technology Data Exchange (ETDEWEB)

The effective sticking coefficient for low energy (< 30 eV) hydrogen ions on titanium gettered aluminium walls has been measured in the Wisconsin Levitated Octupole. A value of greater than 0.75 was measured. The H/sub 2/ effective sticking coefficient for the same conditions is less than 0.01. Seventy-four percent of the wall area of the Octupole is gettered. The effects of recycling on plasma parameters is also discussed.

Garner, H.; Post, R. S.

1981-02-01

191

Analysis of f-p model for octupole ordering in NpO2  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Kubo, Katsunori; Hotta, Takashi

2005-01-01

192

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

Directory of Open Access Journals (Sweden)

Full Text Available In this paper we review the latest developments in the use of severe plastic deformation (SPD techniques for enhancement of hydrogen sorption properties of magnesium and magnesium alloys. Main focus will be on two techniques: Equal Channel Angular Pressing (ECAP and Cold Rolling (CR. After a brief description of these two techniques we will discuss their effects on the texture and hydrogen sorption properties of magnesium alloys. In particular, the effect of the processing temperature in ECAP on texture will be demonstrated. We also show that ECAP and CR have produced different textures. Despite the scarcity of experimental results, the investigations up to now indicate that SPD techniques produce metal hydrides with enhanced hydrogen storage properties.

Daniel Fruchart

2012-08-01

193

Diametrical deformation method for in situ stress and rock property measurement  

Energy Technology Data Exchange (ETDEWEB)

Failure deformation of a borehole boundary in response to hydraulic loading via a plastic cylinder is directly related to both the initial stress state and the material properties of the ground. These relationships are utilized for determination of in situ stress states and material properties of complex geological formations, including fractured hard rock and soft ductile media, by directly measuring diametral deformation of the borehole in relation to the applied pressure. This new method was first developed by means of finite element simulation models and later confirmed by laboratory model studies. This method was then field tested in an outcropping of homogeneous sandstone and later applied to three underground geological formations: highly stratified shale, rock salt, and fractured green schist. Some of the results of these field applications are presented here to illustrate the validity and usefulness of this method, especially for complex ground where the conventional methods of overcoring and hydrofracturing may be ineffective. The instrumentation of this method involves a borehole probe which utilizes electrically powered hydraulic pumping and computerized data acquisition for rapid measurement and on-site analysis. The significance of the new method is its ability to obtain input data of in situ stress states and material properties for finite element analysis of earth structures in complex ground.

Serata, S.; Kikuchi, S.

1986-03-01

194

Effect of deformation rate on characteristics of mechanical properties of heat treated titanium alloys  

International Nuclear Information System (INIS)

Effect of the deformation rate on strength and plasticity of industrial VT3-1 and VT23 alloys after hardening heat treatment has been investigated. Change in the deformation rate in mechanical tests from the minimum (3.3x10-1 s-1) to the maximum (1.67x10-4 s-1) admissible by the All-Union State Standard is shown to cause the increase of timing resistance of VT3-1 and VT23 alloys by 40...50 MPa, and relative elongation of the VT3-1 alloy decreases by 3%, VT23 alloy does not change practicallyy, relative contraction increases by 8% (VT3-1) and 15% (VT23). The VT23 alloy by virtue of composition and structure peculiarities with strength being practically equal to the VT3-1 alloy has higher values of ductile characteristics. Increase of the deformation rate of the VT3 alloy leads to substantial localization of plastic flow in the sample neck with conservation of high relative elongation. Increase of the strain rate in the range of 3.3x10-5...3.3x10-1 s-1 leads to increase in dipression of mechanical properties of VT3-1 and VT23 alloys in the heat treated state

1986-01-01

195

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

Science.gov (United States)

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

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

2012-10-01

196

Properties of Zr hypernuclei in deformed Skyrme Hartree-Fock approach  

Science.gov (United States)

Properties of the even-N Zr isotopes and their corresponding single-? and double-? hypernuclei are studied in the deformed Skyrme-Hartree-Fock approach. Binding energy, the two-neutron separation energies, radii are studied from beta-stable zone to the neutron drip line in this paper. The neutron drip line nuclei predicted with SLy4 and SkI4 interactions are 122Zr and 138Zr, respectively. The neutron drip line of single-? and double-? hypernuclei are 139?Zr and 1422?Zr with SkI4 interaction, respectively. The predicted hyperon drip line hypernuclei with 80Zr and 138Zr cores are 10020?Zr and 18850?Zr, respectively.

Wei, Ning; Zhou, Xian-Rong; Chen, Fang-Qi

2009-03-01

197

Change of mechanical properties of 1201 welding alloy under deformation and gamma-irradiation action  

International Nuclear Information System (INIS)

The effect of #betta#-irradiation and strain on mechanical properties of the aged 1201 alloy has been studied. It has been shown that the 1201 aluminium alloy straining by a single-axis stretching with the deformation degree of epsilon=3-5% after quenching before artificial ageing leads to the 20-30% strength growth and to 1.5-2 times ductility growth. The process of #betta#-irradiation between strain and artificial ageing increases the alloy strength up to epsilon=9% within the high ductility. The above regularities are also true for welded joint metal

1982-07-01

198

Effects of deformation on the electronic properties of B-C-N nanotubes  

Energy Technology Data Exchange (ETDEWEB)

We apply first-principles methods, using density functional theory, to investigate the effects of flattening deformation on the electronic properties of BC{sub 2}N and C-doped BNNTs. Four different types of BC{sub 2}N structures are considered. Two of them are semiconductors, and the radial compression produces a significant reduction of the energy band gap. The other two types of structures are metallic, and the effect of radial compression is quite distinct. For one of them it is found the opening of a small band gap, and for the other one no changes are observed. For C-doped tubes, it is also found that the electronic properties undergo significant modifications when subjected to radial compression. - Graphical Abstract: We apply first-principles methods, using density functional theory, to investigate the effects of flattening deformation on the electronic properties of BC{sub 2}N and C-doped BNNTs. Four different types of BC{sub 2}N structures are considered. Two of them are semiconductors, and the radial compression produces a significant reduction of the energy band gap. The other two types of structures are metallic, and the effect of radial compression is quite distinct. For one of them it is found the opening of a small band gap, and for the other one no changes are observed. For C-doped tubes, it is also found that the electronic properties undergo significant modifications when subjected to radial compression. Highlights: Black-Right-Pointing-Pointer We investigated electronic properties of flattened BC{sub 2}N nanotubes. Black-Right-Pointing-Pointer The electronic states depend strongly on compression. Black-Right-Pointing-Pointer It is studied flattened BN nanotubes doped with a carbon atom. Black-Right-Pointing-Pointer The flattened C-doped structures, presents a significant reduction of the gap.

Azevedo, S., E-mail: sazevedo@fisica.ufpb.br [Departamento de Fisica, Universidade Federal da Paraiba, Caixa Postal 5008, 58059-900 Joao Pessoa-PB (Brazil); Rosas, A. [Departamento de Fisica, Universidade Federal da Paraiba, Caixa Postal 5008, 58059-900 Joao Pessoa-PB (Brazil); Machado, M. [Departamento de Fisica, Universidade Federal de Pelotas, Caixa Postal 354, 96010-900 Pelotas-RS (Brazil); Kaschny, J.R. [Instituto Federal da Bahia-Campus Vitoria da Conquista, Av. Amazonas 3150, 45030-220 Vitoria da Conquista-BA (Brazil); Chacham, H. [Departamento de Fisica, ICEX, Universidade Federal de Minas Gerais, Caixa Postal 702, 30123-970 Belo Horizonte-MG (Brazil)

2013-01-15

199

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

200

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

Energy Technology Data Exchange (ETDEWEB)

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

Safaeian, O; Tavassoly, M K, E-mail: mktavassoly@yazduni.ac.ir [Atomic and Molecular Group, Faculty of Physics, Yazd University, Yazd (Iran, Islamic Republic of)

2011-06-03

 
 
 
 
201

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

International Nuclear Information System (INIS)

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

2010-11-01

202

Structure and properties of deformed alloys of tungsten-rich corner of W-Mo-Re-Hf-C system  

International Nuclear Information System (INIS)

Main regularities of structure formation and mechanical properties changing are established for deformation of vacuum-melted low alloys in W-Mo-Re-Hf-C system. It is shown that during hot deformation a fibrous structure is formed which provides a dec-- crease of ductile-brittle transition temperature. All the alloys investigated after a 95% reduction are ductile at room temperature. Hot deformation in the range 1450-1350 deg C with 92-93% re-- duction in area does not result in a visible increase of alloy ultimate strength

1982-01-01

203

Microstructure and properties of ceramics and composites joined by plastic deformation  

International Nuclear Information System (INIS)

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

2008-12-20

204

Investigation of the rheological properties of planetary ice-rock analogues using triaxial deformation and neutron diffraction experiments.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this thesis I present work on the rheological properties of ice-rock mixtures, with particular application to the flow of materials in icy planetary bodies. Details of manufacture of analogue samples, triaxial deformation experiments, and combined deformation and neutron diffraction experiments are presented. These experimental results are used to consider the effect of an ice rock rheology on planetary processes through computer modelling of the evolution of the dwarf planet Ceres. Water ...

Middleton, C.

2012-01-01

205

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-01-01

206

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

207

Microstructural evolution and mechanical properties of a copper-zirconium alloy processed by severe plastic deformation  

Science.gov (United States)

A copper alloy, Cu-0.1% Zr, has been processed at room temperature by different techniques of severe plastic deformation (SPD), namely equal-channel angular pressing (ECAP), high-pressure torsion (HPT) and a combination of both processing (ECAP + HPT). The experiments were conducted to evaluate the microstructural evolution and mechanical properties for each of the processed and their combination. A transmission electron microscopy (TEM) and an electron backscatter diffraction (EBSD) techniques were employed to measure the microstructural features, grain size distributions and the distribution of the misorientation angles. The mechanical properties of the processed samples were examined and compared both at a room temperature using microhardness measurements and at an elevated temperature using tensile testing. Using TEM and EBSD techniques, it is demonstrated that these three SPD procedures have a potential for producing an ultrafine-grain structure containing reasonably equiaxed grains with high-angle boundary misorientations. However, microstructures are refined in different level depending on the processing operation. The grain refinement mechanisms are primarily governed by dislocation activities. Microhardness distribution of the strained samples shows that there is a non-uniform of this distribution in the early stages of deformation where the lower hardness values were measured near the bottom of samples for ECAP and at the central region for HPT. This inhomogeneity is gradual decreased with increasing imposed strain and ultimately the microhardness distribution is reasonably homogeneous when the sufficient strain is subjected to the sample. The tensile results demonstrate that the samples after SPD processing exhibit superior mechanical properties with the combination of high strength and ductility compared to the as-received materials where the maximum elongation to failure of ˜240% at 723 K using a strain rate of 1.0 x 10 -4 s-1 is achieved in a sample processed by HPT. This elongation however does not fulfilled the requirements for true superplastic flow where the measured elongation in tension should be at least 400%.

Wongsa-Ngam, Jittraporn

208

Investigations on ground-state properties of deformed nuclei in relativistic mean field theory with parameter set FSUGold  

International Nuclear Information System (INIS)

In this work, we have systemically investigated the ground-state properties of the rare-earth even-even nuclei with the parameter set FSUGold that includes the isoscalar-isovector coupling to soften the symmetry energy. It is the first time that this parameter set is applied to investigate the properties of deformed nuclei. The present study is mainly focused on the nuclei with the known experimental binding energies ranging from Z=58 to Z=70. The calculated binding energies, quadrupole deformations, and charge radii are in good agreement with the available experimental data. It has been shown that the parameter set FSUGold is as successful as the NL3 in reproducing the known ground-state properties of deformed nuclei.

2010-01-01

209

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

International Nuclear Information System (INIS)

Two-mode charge (pair) coherent states have been introduced previously by using the ??| representation. In this paper, we reobtain these states by a rather different method. Then, using the nonlinear coherent state approach and based on a simple manner by which the representation of two-mode charge coherent states is introduced, we generalize the bosonic creation and annihilation operators to the f-deformed ladder operators and construct a new class of f-deformed charge coherent states. Unlike the (linear) pair coherent states, our presented structure has the potential to generate a large class of pair coherent states with various nonclassicality signs and physical properties which are of interest. For this purpose, we use a few well-known nonlinearity functions associated with particular quantum systems as some physical appearances of our presented formalism. After introducing the explicit form of the above correlated states in the two-mode Fock space, several nonclassicality features of the corresponding states (as well as the two-mode linear charge coherent states) are numerically investigated by calculating quadrature squeezing, the Mandel parameter, the second-order correlation function, the second-order correlation function between the two modes and the Cauchy–Schwartz inequality. Also, the oscillatory behaviour of the photon count and the quasi-probability (Husimi) function of the associated states will be discussed. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Coherent states: mathematical and physical aspects’. (paper)

2012-06-22

210

Deformed photon-added nonlinear coherent states and their nonclassical properties  

CERN Document Server

In this paper, we will try to present a general formalism for the construction of {\\it deformed photon-added nonlinear coherent states} (DPANCSs) $|\\alpha, f, m>$, which in special case lead to the well-known photon-added coherent state (PACS) $|\\alpha, m>$. Some algebraic structures of the introduced DPANCSs are studied and particularly the resolution of the identity, as the most important property of generalized coherent states, is investigated. Meanwhile, it will be demonstrated that, the introduced states can also be classified in the $f$-deformed coherent states, with a special nonlinearity function. Next, we will show that, these states can be produced through a simple theoretical scheme. A discussion on the DPANCSs with negative values of $m$, i.e., $|\\alpha, f, -m>$, is then presented. Our approach, has the potentiality to be used for the construction of a variety of new classes of DPANCSs, corresponding to any nonlinear oscillator with known nonlinearity function, as well as arbitrary solvable quantu...

Safaeian, O; 10.1088/1751-8113/44/22/225301

2011-01-01

211

Elastic properties and large deformation of two-dimensional silicene nanosheets using molecular dynamics  

Science.gov (United States)

This paper aims to compute the elastic properties and large deformation of two-dimensional silicene, a low buckled honeycomb structure of silicon, under uniaxial and biaxial tension by implementing molecular dynamics simulations in canonical ensemble (NVT). The results demonstrate that Young's and bulk moduli and ultimate stress of silicene nanosheet are lower than those of graphene. Ultimate strain is found to be higher than that of graphene for armchair silicene, unlike the zigzag one. Moreover, Poisson's ratio of silicene is found to be greater than that of its carbon counterpart due to longer Si-Si bond length and its low buckled honeycomb structure. Further, it is observed that bulk modulus is strongly size-dependent and it decreases by increasing the length of nanosheet. Finally, the silicene behavior under large deformation and fracture pattern are investigated and the formation of topological defects and silicon chains are observed. It is further revealed that the silicene is noticeably weaker than graphene in zigzag direction.

Ansari, R.; Rouhi, S.; Ajori, S.

2014-01-01

212

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2004-09-20

213

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

International Nuclear Information System (INIS)

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

2004-09-20

214

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

International Nuclear Information System (INIS)

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

1995-01-01

215

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

Science.gov (United States)

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

Chan, Kit Yan; Eggleton, Charles

2006-03-01

216

Optimization of the magnetic properties of FePd alloys by severe plastic deformation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A FePd alloy was nanostructured by severe plastic deformation following two different routes: ordered and disordered states were processed by high pressure torsion (HPT). A grain size in a range of 50 to 150 nm is obtained in both cases. Severe plastic deformation induces some significant disordering of the long range ordered L10 phase. However, Transmission Electron Microscopy (TEM) data clearly show that few ordered nanocrystals remain in the deformed state. The deformed materials were anne...

Chbihi, Abdelahad; Sauvage, Xavier; Genevois, Ce?cile; Blavette, Didier; Gunderov, Dmitry; Popov, Alexander

2010-01-01

217

Lattice Distortion and Octupole Ordering Model in CexLa1-xB6  

CERN Document Server

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

Kubo, K; Kubo, Katsunori; Kuramoto, Yoshio

2003-01-01

218

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

1999-03-01

219

Octupole correlations in superdeformed mercury and lead nuclei: A generator-coordinate method analysis  

International Nuclear Information System (INIS)

Axial and non-axial octupole excitations built on superdeformed states of zero spin in 192,194Hg and 194Pb nuclei are studied within the fully microscopic generator-coordinate method using selfconsistent Hartree-Fock BCS states as a basis. Results with the effective interaction SkM* predict vibration energies of 1.9-2.5 MeV, B(E3) values of 15-37 single-particle units and unusually large B(E1) transition rates up to 0.02 W.u. Calculations including both octupole modes with K=0 and K=2 indicate that these modes couple weakly. (orig.)

1993-01-04

220

5- ''octupole'' states in 146,148Nd and 148Sm via proton scattering  

International Nuclear Information System (INIS)

The cross sections for populating the 21+, 31-, and 51- states of 146,148Nd and 148Sm have been determined by inelastic scattering of 26 MeV protons and analyzed using coupled-channels calculations. In these nuclei, the 51- states are usually considered to be ''octupole coupled'' states arising from the coupling of the 21+ and 31- states. It is found that the differential cross sections for excitation of the 51- states are somewhat larger than would be expected for octupole coupled structure. This excess strength can be explained in terms of small admixtures of two quasiparticle excitations in the 51- states

1993-03-01

 
 
 
 
221

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

Science.gov (United States)

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

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

2011-12-01

222

Experimental study of dynamic compressive properties of rigid polyurethane foams under high deformation velocities using an impulsive shock technique  

International Nuclear Information System (INIS)

This paper presents an experimental study on dynamic compressive properties of rigid urethane foams under high deformation velocities realized by means of an impulsive shock device. Two kind of rigid foams are studied within the impulse range: 500 pa. s to 1.200 pa.s. Experimental results are analysed and a comparison between static and dynamic behaviour is made

1978-01-01

223

Effect of Forging Strain Rate and Deformation Temperature on the Mechanical Properties of Warm-Worked 304L Stainless Steel  

Energy Technology Data Exchange (ETDEWEB)

Stainless steel 304L forgings were produced with four different types of production forging equipment – hydraulic press, mechanical press, screw press, and high-energy rate forging (HERF). Each machine imparted a different nominal strain rate during the deformation. The final forgings were done at the warm working (low hot working) temperatures of 816 ?C, 843 ?C, and 871 ?C. The objectives of the study were to characterize and understand the effect of industrial strain rates (i.e. processing equipment), and deformation temperature on the mechanical properties for the final component. Some of the components were produced with an anneal prior to the final forging while others were deformed without the anneal. The results indicate that lower strain rates produced lower strength and higher ductility components, but the lower strain rate processes were more sensitive to deformation temperature variation and resulted in more within-part property variation. The highest strain rate process, HERF, resulted in slightly lower yield strength due to internal heating. Lower processing temperatures increased strength, decreased ductility but decreased within-part property variation. The anneal prior to the final forging produced a decrease in strength, a small increase in ductility, and a small decrease of within-part property variation.

Nathan T Switzner

2010-02-01

224

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

International Nuclear Information System (INIS)

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

2011-06-01

225

The deformation behavior and viscoelastic properties of chondrocytes in articular cartilage.  

Science.gov (United States)

Chondrocytes in articular cartilage utilize mechanical signals in conjunction with other environmental factors to regulate their metabolic activity. However, the sequence of biomechanical and biochemical events involved in the process of mechanical signal transduction has not been fully deciphered. A fundamental step in determining the role of various factors in regulating chondrocyte activity is to characterize accurately the biophysical environment within the tissue under physiological conditions of mechanical loading. Microscopic imaging studies have revealed that chondrocytes as well as their nuclei undergo shape and volume changes in a coordinated manner with deformation of the tissue matrix. Through micromechanical experiments, it has been shown that the chondrocyte behaves as a viscoelastic solid material with a mechanical stiffness that is several orders of magnitude lower than that of the cartilage extracellular matrix. These properties seem to be due to the structure of the chondrocyte cytoskeleton, and in part, the viscoelastic properties of the cell nucleus. The mechanical properties of the pericellular matrix that immediately surrounds the chondrocyte significantly differ from those of the chondrocyte and the extracellular matrix, suggesting that the pericellular matrix plays an important role in defining the mechanical environment of the chondrocyte. These experimentally measured values for chondrocyte and cartilage mechanical properties have been used in combination with theoretical constitutive modeling of the chondrocyte within articular cartilage to predict the non-uniform and time-varying stress-strain and fluid flow environment of the cell. The ultimate goal of these studies has been to elucidate the sequence of biomechanical and biochemical events through which mechanical stress influences chondrocyte activity in both health and in disease. PMID:10912176

Guilak, F

2000-01-01

226

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

227

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

Science.gov (United States)

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

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

2011-09-01

228

Effect of Tempering Time on Microstructure, Tensile Properties, and Deformation Behavior of a Ferritic Light-Weight Steel  

Science.gov (United States)

In the present study, a ferritic light-weight steel was tempered at 973 K (700 °C) for various tempering times, and tensile properties and deformation mechanisms were investigated and correlated to microstructure. ?-carbides precipitated in the tempered band-shaped martensite and ferrite matrix, and the tempered martensite became more decomposed with increasing tempering time. Tempering times for 3 days or longer led to the formation of austenite as irregular thick-film shapes mostly along boundaries between the tempered martensite and the ferrite matrix. Tensile tests of the 1-day-tempered specimen showed that deformation bands were homogeneously spread throughout the specimen, and that the fine carbides were sufficiently deformed inside these deformation bands resulting in high strength and ductility. The 3-day-tempered specimen showed a small amount of boundary austenite, which readily developed voids or cracks and became sites for fracture. This cracking at boundary austenites became more prominent in the 7- and 15-day-tempered specimens, as the volume fraction of boundary austenites increased with increasing tempering time. These findings suggested that, when the steel was tempered at 973 K (700 °C) for an appropriate time, i.e., 1 day, to sufficiently precipitate ?-carbides and to prevent the formation of boundary austenites, that the deformation occurred homogeneously, leading to overall higher mechanical properties.

Han, Seung Youb; Shin, Sang Yong; Lee, Byeong-Joo; Lee, Sunghak; Kim, Nack J.; Kwak, Jai-Hyun

2013-01-01

229

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

International Nuclear Information System (INIS)

The phase stability, deformation mechanisms and mechanical properties of two alloys based on Nb3Al containing additions of Ti have been studied. These two alloys, with nominal compositions (in at.%) of Nb-15Al-10Ti (alloy 1) and Nb-15Al-40Ti (alloy 2), have the B2 crystal structure in as cast form. The ALCHEMI technique has been employed to assess qualitatively the distribution of atom types over the two sublattices of the B2 compounds. It is found that Ti and Al occupy different sublattices in alloy 2. Heat-treatment of alloy 1 at 1,100 C results in the precipitation of an A15 phase in the B2 matrix. Annealing at 900 C for short time introduces an w-phase. Prolonged annealing of alloy 1 at 700 C reveals the presence of an orthorhombic phase. The same orthorhombic phase is also found to exist between 800 and 1,000 C in alloy 2. Specific orientation relationships exist between the matrix phase and precipitates. The yield strength in compression of Alloy 1 and 2 were determined at various temperatures. Alloy 1 is strong compared to superalloy IN 718 over a range of temperatures up to 950 C. Both alloys with the B2 crystal structure are deformed by one or more of the following slip systems, namely (110), (112) and (123). Dislocations with Burgers vector, b, given by b= are present in the form of dissociated superpartial pairs, each with b=1/2. The inherent ductility of both alloys is indicated by the active slip systems and 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

1993-09-26

230

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

International Nuclear Information System (INIS)

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

2011-05-01

231

On the chemistry, microstructure, and deformation properties of cement pastes: Towards a new strategy for controlling drying shrinkage  

Science.gov (United States)

The research reported in this thesis covers a number of topics that include aspects of chemistry, microstructure, deformation of cement pastes. An overall goal has been to develop a materials science basis for controlling drying shrinkage. This goal is ambitious and there is a great deal of research still required. However, progress has been made and it is reported here. First, a new phase diagram believed to be consistent with the cement hydration process has been developed. This diagram assumes that a metastable C-S-H phase, analogous to jennite but without polymerized silicate chains, is responsible for the induction period, and that the final hydration reaction is a eutectic solidification reaction consisting of layered calcium silicate hydrate and calcium hydroxide. Second, the effects of chemical admixtures on the rheological behavior of cement in its fluid state was explored. It was found that steric hindrance must play a role in the mechanism behind the dispersing properties of these chemicals. Third, new deformation mapping technique used to investigate the drying shrinkage behavior of neat cement pastes has been developed. This technique requires only two digital images; the source of the images and the source of the deformation does not affect this analysis. A dynamic new picture of drying shrinkage deformation has emerged. Both rarefactions and compactions are found to develop within the microstructure under all drying conditions, and these deformed regions interact to control the overall deformation of the material. Finally, a finite element model was used to further explore drying shrinkage in cement pastes and mortars. It was found that the drying shrinkage of neat cement pastes appears to be controlled by only a subset of calcium silicate hydrate; this subset is detectable by nitrogen sorption techniques. This relationship is perhaps the second microstructure-property relationships known for cement pastes and can be used as a design tool for developing new materials with optimum drying shrinkage properties.

Neubauer, Christopher Michael

232

Cryogenic compressive deformation properties of superconducting coil packs simulated for helical coils on LHD [Large Helical Davice] program  

International Nuclear Information System (INIS)

An electromagnetic force of above 10 MN/m will act on the helical coils in the Large Helical Device. To investigate the deformation properties of the helical coils, the coil pack, which consists of 16 superconductors, was prepared and a compressive mechanical test was carried out at 4.2 K. Also, the apparent rigidity was discussed on the basis of the mixture law. The results show that the gaps between the electric insulation spacer and the superconductor give rise to hysteresis on the compressive load-deformation curve on the first cycle. The estimated result of the coil pack rigidity gives good agreement with the experiment. (Author)

1992-01-01

233

Self-consistent semiclassical sum rule approach to nuclear giant octupole resonances  

International Nuclear Information System (INIS)

With the nucleon densities ?n(r) and ?p(r) determined by a self-consistent semiclassical calculation and the sum rule approach, the average excitation energies of nuclear isoscalar giant octupole resonances (GOR) are evaluated. The temperature dependence of these energies is analysed. Some of the results are compared with experimental data

1990-01-01

234

Possible discontinuity in octupole behaviour in the Pt-Hg region  

International Nuclear Information System (INIS)

Values of B(E3;O1+ ? 31-) have been determined for the nuclei 194,196,198Pt by Coulomb excitation, giving 0.125(8), 0.102(4), and 0.084(18) e2b3, respectively. The results are discussed within the context of a previously suggested discontinuity in octupole behaviour in the Pt-Hg region

1989-01-01

235

Determination of the transition charge density of the octupole vibration in /sup 208/Pb  

Energy Technology Data Exchange (ETDEWEB)

The transition charge density for the octupole vibration of /sup 208/Pb has been determined with an unprecedented accuracy for an inelastic transition. jA comparison with some of the best theoretical calculations shows a persistent discrepancy in the interior of the nucleus which offers a measure of the limitations of the various theoretical approaches considered.

Goutte, D.; Bellicard, J.B.; Cavedon, J.M.; Frois, B.; Huet, M.; Leconte, P.; Ho, P.X.; Platchkov, S.; Heisenberg, J.; Lichtenstadt, J.; Papanicolas, C.N.; Sick, I.

1980-11-17

236

Effect of high strain-rate deformation on surface mechanical properties of stainless steel after peening  

International Nuclear Information System (INIS)

This paper investigated the effect of high-rate deformation on the change of mechanical properties on the surface of metallic materials during a peening as a surface modification of metallic materials. Especially, we focused on the introduced compressive residual stress and the yield stress increase on the surface, which brings about the improvement of fatigue strength of the materials after peening. For this purpose, we compared the results using two different peening. One is a static indentation with a steel ball, and the other is a dynamic peening with high velocity. The residual stresses were obtained through the comparison with experimental depths using an elastic-viscoplastic finite element model for the peening, and the variation in yield stress was also obtained using indentation tests and numerical analysis of indentation tests. As a result, we clarified the effect of strain-rate on the variation in yield stress and induced residual stress. Especially, the compressive residual stress and the increments of yield stress of the surface layer within 600?m depth after dynamic peening was larger than that after static peening. (author)

2010-12-01

237

The creep deformation properties of HANA-3 and HANA-6 alloys under applied stresses  

International Nuclear Information System (INIS)

The creep deformation of Zr-alloy cladding is one of the important mechanical properties for determining the nuclear fuel cladding performance, especially heat transfer from fuel to cladding besides mechanical wear between cladding and grid. An understanding of the creep behaviour of Zr-alloy cladding is required to not only secure the safety and the reliability of the fuel rods in a reactor but also the thermal performance and mechanical integrity of fuel rods. The creep characteristics of the Zr-1.5Nb-0.4Sn- 0.1Fe-0.1Cu (HANA-3) and Zr-1.1Nb-0.05Cu (HANA- 6) alloys which are Korea's prospecting candidate nuclear fuel cladding materials were investigated in the temperature range from 300 .deg. C to 500 .deg. C and in the stress range from 50 MPa to 250 MPa along the rolling direction. The creep rates ranges in these tests were 1.27x10-10 s-1 to 4.7x10-7 s-1. The activation energies for the creep were also estimated to make an assessment the creep mechanisms in this alloy

2007-05-10

238

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

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

239

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

240

An interacting boson version of reflection-asymmetric shape deformation  

International Nuclear Information System (INIS)

In order to discuss octupole deformation, we present a model that treats f bosons on an equal footing with the s and d bosons of the IBA. A more flexible version incorporates p bosons as well and has two useful dynamical symmetry limits. The author discusses the application of these models to the light-actinide region of the periodic table, where stable reflection asymmetry is thought to be important

1986-01-01

 
 
 
 
241

Interplay of inertia and deformability on rheological properties of a suspension of capsules  

CERN Document Server

The interplay of inertia and deformability has a substantial impact on the transport of soft particles suspended in a fluid. However, to date a thorough understanding of these systems is still missing and only a limited number of experimental and theoretical studies is available. We combine the finite-element, immersed-boundary and lattice-Boltzmann methods to simulate three-dimensional suspensions of soft particles subjected to planar Poiseuille flow at finite Reynolds numbers. Our findings confirm that the particle deformation and inclination increase when inertia is present. We observe that the Segr\\'e-Silberberg effect is unstable with respect to the particle deformability. Depending on the deformability and strength of inertial effects, inward or outward lateral migration of the particles takes place. In particular, for increasing Reynolds numbers and strongly deformable particles, distinct flow focusing emerges which is accompanied by a non-monotonic behaviour of the apparent suspension viscosity and th...

Krueger, Timm; Harting, Jens

2013-01-01

242

Effect of non-uniform deformation on properties of forged circular kilns  

International Nuclear Information System (INIS)

Non-uniformity of deformation was studied in model conditions in circular forged products from austenitic stainless steels. An extensive area with small local deformations was observed around forging edges. The study of samples from the edges and the central part of forgings showed significant differences in the microstructure, yield point and the resistance to intergranular corrosion. The results are shown in tables and graphs. (J.B.)

1978-11-01

243

Tensile properties and deformation - induced martensitic transformation at cryogenic temperatures in Fe-Cr-Ni-Mn-N alloys  

International Nuclear Information System (INIS)

The tensile properties and changes in microstructures during tensile deformation in Fe-Cr-Ni-Mn-N alloys with a variation of C and N contents have been investigated over the temperature range of 293-4.2 K. It was found that with decreasing temperature the deformation-induced martensitic transformation started at 173 K in the process of ?????'; the amount of ?' martensite formed with maximum uniform strain was greater at 77 K than at 173 or 4.2 K. For the formation of ?' martensite a critical strain was required, and the amount of ?' martensite increased with increasing deformation strain. With the increase in the contents of C and N, the critical strain and the tendency for the increase in the amount of ?' martensite with strain decreased. The results show that both C and N can lead to some increase in the yield and ultimate strengths and a decrease in the elongation, while the deformation-induced martensitic transformation is strongly restrained by the increase in C or N content

1995-07-17

244

On the ?-decay of the isoscalar 1(h/2?)? giant octupole resonance in the A=90 mass region  

International Nuclear Information System (INIS)

The ? decay of the isoscalar 1 (h/2?)? giant octupole resonance was investigated in (?,?'?) coincidence experiments on 90Zr, 92Mo and 96Mo using the 50 MeV ? beam of the Heidelberg boosted MP tandem. ? rays were detected in both Ge(Li) diodes and the Darmstadt-Heidelberg 4? crystal ball spectrometer. Multipole assignments, lifetimes, branching ratios and multiplicity distributions have been quantified. The data reveal the microscopic structure of the various octupole components. (orig.)

1983-01-01

245

Effects of degree of deformation on the microstructure, mechanical properties and texture of hybrid-reinforced titanium matrix composites  

International Nuclear Information System (INIS)

Titanium matrix composites reinforced by TiB whiskers and La2O3 particles are synthesized in a consumable vacuum arc remelting furnace by an in situ technique based on the reaction between Ti, LaB6 and oxygen in the raw material. The titanium matrix composites are hot rolled with degrees of deformation of 60%, 80%, 90% and 95%. The effects of the hot rolling degree of deformation on the mechanical properties of the composites are investigated by experiment and modeling. In particular, the variation in the inclination of the TiB whiskers during rolling is quantified in the model. The results show that, with increasing degree of deformation, the mechanical properties of composites are improved. Modeling of the mechanical properties reveals that grain refinement and TiB whisker rotation during rolling contribute to the improvement in the yield strength of the titanium matrix composites. Electron backscatter diffraction and transmission electron microscopy observations are used to study the texture of the composites. It is found that the orientation relationships between Ti matrix and TiB whiskers are [1 1 ?2 0]Ti || [0 1 0]TiB, (0 0 0 1)Ti || (0 0 1)TiB and (1 ?1 0 0)Ti || (1 0 0)TiB. TiB whiskers rotate in the rolling direction (RD) with increasing degree of deformation, which results in a higher intensity [1 1 ?2 0]Ti || RD fiber due to the special orientation relationship between TiB and the Ti matrix.

2012-04-01

246

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

Energy Technology Data Exchange (ETDEWEB)

Deformed microstructure and mechanical properties of AM60B magnesium alloy under hypervelocity impact at a speed of 4 km s{sup -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 {l_brace}101-bar 2{r_brace}, {l_brace}101-bar 1{r_brace} 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.

Zou, D.L. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Zhen, L., E-mail: lzhen@hit.edu.cn [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Zhu, Y. [School of Aerospace, Harbin Institute of Technology, Harbin 150001 (China); Xu, C.Y.; Shao, W.Z. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Pang, B.J. [School of Aerospace, Harbin Institute of Technology, Harbin 150001 (China)

2010-06-15

247

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

International Nuclear Information System (INIS)

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

2013-06-25

248

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.

2011-11-01

249

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

CERN Document Server

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

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

2011-01-01

250

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

CERN Multimedia

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

251

Octupole correlations in superdeformed mercury and lead nuclei: A generator-coordinate method analysis  

Energy Technology Data Exchange (ETDEWEB)

Axial and non-axial octupole excitations built on superdeformed states of zero spin in [sup 192,194]Hg and [sup 194]Pb nuclei are studied within the fully microscopic generator-coordinate method using selfconsistent Hartree-Fock BCS states as a basis. Results with the effective interaction SkM[sup *] predict vibration energies of 1.9-2.5 MeV, B(E3) values of 15-37 single-particle units and unusually large B(E1) transition rates up to 0.02 W.u. Calculations including both octupole modes with K=0 and K=2 indicate that these modes couple weakly. (orig.).

Skalski, J.; Heenen, P.H. (Service de Physique Nucleaire Theorique ULB, Brussels (Belgium)); Bonche, P. (Service de Physique Theorique, CEN Saclay, 91 - Gif-sur-Yvette (France)); Flocard, H. (Div. de Physique Theorique, INP, 91 - Orsay (France)); Meyer, J. (IPNL, Lyon-1 Univ., 69 - Villeurbanne (France))

1993-01-04

252

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

International Nuclear Information System (INIS)

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

1997-09-01

253

Lower hybrid heating associated with mode conversion on the Wisconsin octupole  

Energy Technology Data Exchange (ETDEWEB)

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

Owens, T.L.

1979-08-01

254

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

International Nuclear Information System (INIS)

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

255

High-power ion-cyclotron heating on the levitated octupole  

Energy Technology Data Exchange (ETDEWEB)

Experiments are underway in the Wisconsin Levitated Toroidal Octupole to create hot, dense plasmas to facilitate the study of ..beta.. limits and related phenomena such as Pfirsch-Schlueter and bootstrap currents. The question of ballooning mode instability limits on ..beta.. = 8 ..pi..nk(T/sub i/+T/sub e/)/B/sup 2/ is of general importance for all toroidal systems, and ICRF heating should permit study of high ..beta.. plasmas with lower collisionality and smaller gyroradii than those of the high ..beta.. gun-injected plasmas currently under study in the Octupole. To these ends we are developing sources capable of delivering 4 MW to the plasma (1.5 MW coupled to the plasma to date, the rest under development).

Dexter, R.N.; Fortgang, C.M.; Prager, S.C.; Sprott, J.C.; Strait, E.J.; Twichell, J.C.

1982-03-01

256

Cold deformation effect on the microstructures and mechanical properties of AISI 301LN and 316L stainless steels  

International Nuclear Information System (INIS)

As austenitic stainless steels have an adequate combination of mechanical resistance, conformability and resistance to corrosion they are used in a wide variety of industries, such as the food, transport, nuclear and petrochemical industries. Among these austenitic steels, the AISI 301LN and 316L steels have attracted prominent attention due to their excellent mechanical resistance. In this paper a microstructural characterization of AISI 301LN and 316L steels was made using various techniques such as metallography, optical microscopy, scanning electronic microscopy and atomic force microscopy, in order to analyze the cold deformation effect. Also, the microstructural changes were correlated with the alterations of mechanical properties of the materials under study. One of the numerous uses of AISI 301LN and 316L steels is in the structure of wagons for metropolitan surface trains. For this type of application it is imperative to know their microstructural behavior when subjected to cold deformation and correlate it with their mechanical properties and resistance to corrosion. Microstructural analysis showed that cold deformation causes significant microstructural modifications in these steels, mainly hardening. This modification increases the mechanical resistance of the materials appropriately for their foreseen application. Nonetheless, the materials become susceptible to pitting corrosion.

2011-02-01

257

Creep deformation and rupture properties of unirradiated Zircaloy-4 nuclear fuel cladding tube at temperatures of 727 to 857 K  

Science.gov (United States)

Creep deformation and rupture properties of an unirradiated Zircaloy-4 tube were examined at temperatures of 727 to 857 K to obtain data for evaluating spent fuel integrity under the off-normal dry storage condition. Creep tests were carried out on internally gas pressurized tubular specimens with end plugs welded to both ends. The hoop creep strain up to the steady-state creep region was given by the following equation: ? = 0.05{1- exp[-10( ?st) 0.51]} + ?st, where ?s = 1.02 × 10 5( E/ T) exp (4060 ?/ E) exp (- Q/ RT) ( S-1), t is time (s), E is the elastic modulus (MPa), T is the temperature (K), ? is the applied stress (MPa), R is the gas constant (= 8.314 J/mol K), and Q the apparent activation energy (233 kJ/mol). The total creep deformation curve over the accelerated creep region could also be presented by the equation expressed as a function of true stress formulated on the basis of constant stress creep data. It is inferred that the transition from the steady-state to the accelerated creep region occurs without changing the deformation mechanism. It was also shown that most of the creep strain to rupture exceeded 100% and Zircaloy-4 had an extremely ductile rupture property.

Mayuzumi, Masami; Onchi, Takeo

1990-12-01

258

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

259

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

260

Elastic properties of the red blood cell membrane that determine echinocyte deformability.  

Science.gov (United States)

The natural biconcave shape of red blood cells (RBC) may be altered by injury or environmental conditions into a spiculated form (echinocyte). An analysis is presented of the effect of such a transformation on the resistance of RBC to entry into capillary sized cylindrical tubes. The analysis accounts for the elasticity of the membrane skeleton in dilation and shear, and the local and nonlocal resistance of the bilayer to bending, the latter corresponding to different area strains in the two leaflets of the bilayer. The shape transformation is assumed to be driven by the equilibrium area difference (delta A(0), the difference between the equilibrium areas of the bilayer leaflets), which also affects the energy of deformation. The cell shape is approximated by a parametric model. Shape parameters, skeleton shear deformation, and the skeleton density of deformed membrane relative to the skeleton density of undeformed membrane are obtained by minimization of the corresponding thermodynamic potential. Experimentally, delta A(0) is modified and the corresponding discocyte-echinocyte shape transition obtained by high-pressure aspiration into a narrow pipette, and the deformability of the resulting echinocyte is examined by whole cell aspiration into a larger pipette. We conclude that the deformability of the echinocyte can be accounted for by the mechanical behavior of the normal RBC membrane, where the equilibrium area difference delta A(0) is modified. PMID:13680208

Kuzman, D; Svetina, S; Waugh, R E; Zeks, B

2004-02-01

 
 
 
 
261

Influence of plastic deformation and alloying on magnetic properties and structure of Fe-Mo-Ni base alloys for permanent magnets  

International Nuclear Information System (INIS)

The effect of high degrees of preliminary plastic deformation on hysteresis magnetic properties obtained after annealing is investigated. The effect of gallium additions on magnetic properties of Fe-Mo-Ni alloys is also studied. Plastic deformation with high degrees of reduction (>99%) preceding annealing is found to increase the coercive force of Fe-Mo-Ni alloys. Gallium doping preserves alloy plasticity at increased molybdenum content, that permits to additionally increase the magnetic characteristics

1988-01-01

262

Octupole vibration in the superdeformed "1"9"6Pb nucleus  

International Nuclear Information System (INIS)

The study of the superdeformed (SD) "1"9"6Pb 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)

1999-01-01

263

f-Deformed Squeezed Vacuum and First Excited States, Their Superposition and Corresponding Nonclassical Properties  

Science.gov (United States)

In this paper, we introduce two new classes of nonlinear squeezed states that we name as f-deformed squeezed vacuum state |?, f>even and f-deformed squeezed first excited state |?, f>odd, which according to their production processes, essentially include only even and odd bases of Fock space, respectively. In the continuation, we introduce the superposition of these two distinct nonlinear squeezed states with a respective phase ?. Then, some of the criteria which imply the nonclassicality of the states, such as Mandel parameter, second-order correlation function, quadrature squeezing, amplitude-squared squeezing, Husimi and Wigner–Weyl quasi-distribution functions, are numerically examined. At last, by considering a well-known nonlinearity function associated with a nonlinear physical system, we present our results which outcome from the numerical calculations. It is shown that, the introduced f-deformed states can reveal high nonclassical features.

NoormandiPour, A.; M. K., Tavassoly

2014-04-01

264

Study of transition nuclei deformation. Study of shape transformation mechanisms and rigidity properties of these nuclei  

International Nuclear Information System (INIS)

The deformation of transition nuclei has been studied by means of a rotor plus particle model, where the Fermi level lies at the beginning or at the end of high j subshells, the observation of high spin collective states gives the sign of the deformation. These states, selectively populated in (heavy ions-xn) reactions, have been studied by their gamma decay. The limits of the model have been studied. Near closed shells, it is a weak coupling model which is relevant. Large deformations (? approximately equal to 0.3) have been proposed in nuclei of the g 9/2 region. In the transition region Z<82, the experimental results suggest a localization of the wave functions in spite of a soft potential. Mechanisms of shape transitions have been found. Coriolis effect on core nucleons has been discussed

1976-01-01

265

Steel Processing Properties and Their Effect on Impact Deformation of Lightweight Structures  

Energy Technology Data Exchange (ETDEWEB)

The objective of the research was to perform a comprehensive computational analysis of the effects of material and process modeling approaches on performance of UltraLight Steel Auto Body (ULSAB) vehicle models. The research addressed numerous material related effects, impact conditions as well as analyzed the performance of the ULSAB vehicles in crashes against designs representing the current US vehicle fleet. This report is organized into three main sections. The first section describes the results of the computational analysis of ULSAB crash simulations that were performed using advanced material modeling techniques. The effects of strain-rate sensitivity on a high strength steel (HSS) intensive vehicle were analyzed. Frontal and frontal offset crash scenarios were used in a finite element parametric study of the ULSAB body structure. Comparisons are made between the crash results using the piece-wise-linear isotropic plasticity strain-rate dependent material model, and the isotropic plasticity material model based on quasi-static properties. The simulation results show the importance of advanced material modeling techniques for vehicle crash simulations due to strain-rate sensitivity and rapid hardening characteristics of advanced high strength steels. Material substitution was investigated for the main frontal crush structure using the material of similar yield stress a significantly different strain-rate and hardening characteristics. The objective of the research presented in Section 2 was to assess the influence of stamping process on crash response of ULSAB vehicle. Considered forming effects included thickness variations and plastic strain hardening imparted in the part forming process. The as-formed thickness and plastic strain for front crash parts were used as input data for vehicle crash analysis. Differences in structural performance between crash models with and without forming data were analyzed in order to determine the effects and feasibility of integration of forming processes and crash models. Computational analysis of vehicle-to-vehicle crashes between ULSAB and conventional car designs is reported in Section 3. The study involved vehicles of comparable weights and dimensions to assess the compatibility of the ULSAB with existing designs. Deformation and acceleration data for crashed vehicles were analyzed. Vehicle-modeling approaches have strong influence on computational results and the requirements for compatibility of models were identified for future research on vehicle-to-vehicle crash modeling.

Simunovic, S

2003-09-23

266

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

CERN Document Server

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

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

2013-01-01

267

Classical bifurcation and enhancement of quantum shells: Systematic analysis of reflection-asymmetric deformed oscillator  

International Nuclear Information System (INIS)

The correspondence between classical periodic orbits and quantum shell structure is investigated for a reflection-asymmetric deformed oscillator model as a function of quadrupole and octupole deformation parameters. The periodic orbit theory reveals several aspects of quantum level structure for this non-integrable system. Good classical-quantum correspondence is obtained in the Fourier transform of the quantum level density, and the importance of periodic orbit bifurcation is demonstrated. A systematic survey of the local minima of shell energies in the two-dimensional deformation parameter space shows that prominent shell structures do emerge at finite values of the octupole parameter. Correspondences between the regions exhibiting strong shell effects and the classical bifurcation lines are investigated, and the significance of these bifurcations is indicated. (orig.)

1995-09-11

268

Nuclear deformation, cluster structure, fission and cluster radioactivity  

International Nuclear Information System (INIS)

Usually nuclei are considered to be spherical or quadrupole deformed in the groundstate. Sometimes small static octupole moments are considered to understand relatively strong E1 transition probabilities. Alternatively naive cluster models (a core plus an ? particle) were proposed. Of course, if the deformation becomes larger nuclei undergo fission; symmetric and asymmetric one. Theory predicts also superasymmetric fission connected with the break-up into a binary configuration with a cluster of the size of Ni. The authors discuss how, if fission asymmetry becomes larger and larger, fission becomes identical with what is commonly called radioactivity

1986-04-20

269

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

270

Effect of temperature and rate of deformation on mechanical properties in 15Kh5M steel  

International Nuclear Information System (INIS)

Results of tensile tests carried out for specimens of steel at the temperatures of 293...973 K and deformation rates of 8.33 (10"-"3...10"-"7) c"-"1 are presented. It is shown that testing conditions affect the strength and ductility characteristics for the 15Kh5M steel. Dependences of the ductility characteristics are of v-like form. Minima of all v-like curves of the uniform component of the relative elongation are at 773 K. A decrease in the deformation rate results in the growth of the relative elongation and its uniform component as well as of a zone of deformation localization in the region of the specimen neck. A considerable local plastic deformation is shown to precede a failure of the 15Kh5M steel pipe under conditions of operation. A low sensitivity of 15Kh5M steel to a stress concentration within the temperature range of 293...843 K is established

1986-02-01

271

Effect of substrate deformation on functional properties of atomic-layer-deposited TiO2 coatings on stainless steel  

International Nuclear Information System (INIS)

Changes in the functional properties of 50 and 100 nm thick anatase-type and of 100 and 150 nm thick rutile-type atomic-layer-deposited TiO2 coatings with increasing tensile deformation of AISI 304 stainless steel substrate up to 40% strain were studied. All as-received coatings exhibited good photoelectrochemical and photocatalytic activity as well as photohydrophilicity, but the photocatalytic activity of the rutile-type coatings was only one third of that of the anatase-type coatings. The deformation induced changes in the functional properties depended strongly on the type and thickness of the coating. For the 50 nm anatase-type coating, all the monitored functional properties were severely reduced when the applied strain was 1.4% and higher. Rest of the coatings showed also considerable, but more gradual, decrease of the photoelectrochemical and photocatalytic activity with increasing strain. Least affected was the photohydrophilicity which remained approximately constant until 30% applied strain for the 100 nm coatings, and showed some variation for the 150 nm coating. The possible reasons for the observed behavior are discussed.

2009-05-01

272

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

273

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

Science.gov (United States)

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

Maharaj, Dave

2014-01-01

274

Temperature and preliminary deformation influence on micromechanical and acoustic-emission properties of MgB single crystals  

International Nuclear Information System (INIS)

The MgO single crystals were subjected to the annealing at Tan=150-600 degrees as well as to the plastic deformation over ?=0-6% at 150 and 600 degrees. The resting influence on the mechanical properties of these samples was investigated. It was established that with increasing of Tan and ? at Tdef<300 degrees the microhardness increases and the acoustic emission decreases. Thus, the conditions for increasing of strength and decreasing of brittleness of MgO crystals were revealed. (authors)

2007-01-01

275

Density and superconducting properties of YBa_2Cu_3O_y ceramics after deformation in metallic envelope  

International Nuclear Information System (INIS)

For YBa_2Cu_3O_y ceramics in a copper envelope the strain effect (?) on density (?) and superconducting properties (T_c, ?T_c, j_c) has been investigated. The deformation has been performed by pressing and hydroextrusion with subsequent rolling and drawing. The strain growth has been found to promote a decrease of temperatures of the middle and the end of superconducting transition. The temperature of transition beginning remains equal to 91-93 K for all ? values. Ceramics sintering at 935-985 deg C leads to superconducting transition of initial type. The samples of superconducting wire with copper cover and aluminium interlayer have been prepared

1994-02-01

276

Even and odd q-deformed charge coherent states and their nonclassical properties  

International Nuclear Information System (INIS)

Even and odd q-deformed charge coherent states are constructed, their (over)completeness proved and their generation explored. A D-algebra realization of the SUq(1,1) generators is given in terms of them. They are shown to exhibit SUq(1,1) squeezing and two-mode q-antibunching, but neither one-mode, nor two-mode q-squeezing

2003-10-20

277

Tensile and electrical properties of Al-Si alloys under combined torsion-tension deformation.  

Science.gov (United States)

The relation between tensile strain DL/L0 and the relative change in resistance DR/R0 caused by torsion-tension deformation for Al-Si samples pre-annealed at different temperatures (room temperature up to 773 K) was studied. The empirical relation DL/L0 = kDR/R0 was found, where k is a constant depending on the silicon content and its distribution in the matrix.

Youssef, Tawfick H.; Saadalah, Fardos A.; Bishay, Isis K.

278

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

Science.gov (United States)

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

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

2014-03-01

279

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

2001-03-01

280

Effect of V and Nb additions on microstructure, properties, and deformability of Ti-45Al-9 (V, Nb, Y alloy  

Directory of Open Access Journals (Sweden)

Full Text Available Ti-45Al-9(V, Nb, Y alloys with four different x=V/Nb (atomic ratio x = 1, 1.5, 2 and 3.5 have been prepared, and the microstructures, properties and hot deformation behaviors were investigated. SEM, XRD and TEM results showed that Ti-45Al-9(V, Nb, Y alloys were mainly composed of ?, ?2, and ? phase, and the volume fraction of ? phase increased with the increase of the atomic ratio of V/Nb. The alloys were featured with lamellar microstructure with ? and ? phases locating at the colony boundaries, and some ? precipitates appearing at ?/? interfaces. It was found that the colony size decreased with the increase of x. The alloys exhibited moderate mechanical properties at room temperature, with a yield strength of over 600 MPa, and fractures showed mainly translamellar character. The alloy with x=3.5 exhibited the best deformability at elevated temperature and that with x=1 had superior oxidation resistance at 800 ?.

Yang Fei

2010-11-01

 
 
 
 
281

Effect of preliminary plastic deformation on the structure and physicomechanical properties of aging invar alloy N30K10T3  

International Nuclear Information System (INIS)

A study is made into the effect of decomposition of deformed supersaturated solid solution on hardness, electric conductivity, magnetic susceptibility and linear thermal expansion in N30K10T3 invar on aging. It is shown that cold plastic deformation increases hardness by 30-50 %, has no effect on electric conductivity and decreases magnetic susceptibility of the material. Deformed invar has low value of thermal expansion coefficient at the room temperature but it increases with aging temperature. Phase studies revealed a number of crystal-phase transformations in the invar under strain aging which are responsible for variations of physical and mechanical properties

2006-04-01

282

Characterization of $({\\cal R},p,q)-$deformed Rogers-Szeg\\"o polynomials: associated quantum algebras, deformed Hermite polynomials and relevant properties  

CERN Document Server

This paper addresses a new characterization of $({\\cal R},p,q)-$deformed Rogers-Szeg\\"o 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 $({\\cal R},p,q)-$deformed Hermite polynomials and their recurrence relation are also deduced. Novel relations are provided and discussed.

Kyemba, J D Bukweli

2012-01-01

283

Evaluation of Tensile Deformation Properties of Friction Stir Processed Pure Copper: Effect of Processing Parameters and Pass Number  

Science.gov (United States)

In this work, the tensile behavior of pure copper including ultimate tensile stress, yield stress, and elongation in the specimens friction stir processed under different processing parameters and pass adding was investigated in detail. The effect of strain hardening, grain refinement, and heat input on the tensile properties of these specimens was explained as well. It was observed that, regarding the aforementioned factors, the processing parameters and pass number could have considerable effects on the tensile deformation properties of the pure copper such as 300 and 47% enhancements in elongation and ultimate strength, respectively. It was demonstrated that higher passes resulted in the development of ultrafine grains (up to 700-800 nm) in the specimens. The fracture surface morphology was also used to further support the elongation results.

Barmouz, Mohsen; Besharati Givi, Mohammad Kazem; Jafari, Jalal

2014-01-01

284

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

285

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

286

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

287

Submicrocrystalline structure formation in titanium under plastic deformation and its influence on mechanical properties  

International Nuclear Information System (INIS)

Dynamic recrystallization in commercial titanium VT1-00 under hot deformation in the temperature range of mechanical twinning (lower 0.5Tmelt) was investigated. Compression tests were carried out in the range of 450-650 deg C at strain rate of 3x10-4 s-1 using specimens with initial grain size of 150 ?m. It is found that under 75% reduction at 450 deg C the microstructure with grain size of 0.2 ?m is formed. The difference in mechanical behaviour of submicrocrystalline and coarse-grained titanium is shown. 17 refs.; 4 figs

1996-01-01

288

Surface properties of elastically deformed copper electrode in alkali metal chloride melts  

Science.gov (United States)

The estans of a copper polycrystalline electrode in the NaCl, KCl, and CsCl melts and the NaCl-KCl and NaCl-CsCl eutectics is measured at various temperatures. The zero-charge potential of the elastically deformed electrode in these systems is determined. A mechanism is proposed for the interaction between salt-phase anions and the copper surface. It consists in the formation of a covalent bond between the atoms of a positively charged copper surface and the salt-phase anions with partial charge transfer to the metal.

Stepanov, V. P.; Sitnikov, L. V.

2014-02-01

289

Contribution of the disturbed dislocation slip planes to the electrical properties of plastically deformed silicon  

Energy Technology Data Exchange (ETDEWEB)

The deep-level centers introduced by the plastic deformation at 680 deg. C in p-type silicon are quantitatively studied by the electron beam induced current (EBIC) and DLTS techniques. It is shown that the DLTS signal is higher than that could be ascribed to the centers located at (or close to) dislocations. In opposite, the number of electrically active defects in the dislocation trails, which is estimated from the EBIC contrast, easily explains the DLTS signal. The possible nature of defects in the dislocation trails is discussed.

Feklisova, O.V.; Yakimov, E.B.; Yarykin, N

2003-12-31

290

Contribution of the disturbed dislocation slip planes to the electrical properties of plastically deformed silicon  

International Nuclear Information System (INIS)

The deep-level centers introduced by the plastic deformation at 680 deg. C in p-type silicon are quantitatively studied by the electron beam induced current (EBIC) and DLTS techniques. It is shown that the DLTS signal is higher than that could be ascribed to the centers located at (or close to) dislocations. In opposite, the number of electrically active defects in the dislocation trails, which is estimated from the EBIC contrast, easily explains the DLTS signal. The possible nature of defects in the dislocation trails is discussed

2003-12-31

291

Joint Probability Distribution Function for the Electric Microfield and its Ion-Octupole Inhomogeneity Tensor  

International Nuclear Information System (INIS)

From experiments, see e.g. [W. Wiese, D. Kelleher, and D. Paquette, Phys. Rev. A 6, 1132 (1972); V. Helbig and K. Nich, J. Phys. B 14, 3573 (1981).; J. Halenka, Z. Phys. D 16, 1 (1990); . Djurovic, D. Nikolic, I. Savic, S. Sorge, and A.V. Demura, Phys. Rev. E 71, 036407 (2005)], results that the hydrogen lines formed in plasma with Ne ? 1016 cm-3 are asymmetrical. The inhomogeneity of ionic micro field and the higher order corrections (quadratic and next ones) in perturbation theory are the reason for such asymmetry. So far, the ion-emitter quadrupole interaction and the quadratic Stark effect have been included in calculations. The recent work shows that a significant discrepancy between calculations and measurements occurs in the wings of H-beta line in plasmas with cm-3. It should be stressed here that e.g. for the energy operator the correction raised by the quadratic Stark effect is proportional to (where is the emitter-perturber distance) similarly as the correction caused by the emitter-perturber octupole interaction and the quadratic correction from emitter-perturber quadrupole interaction. Thus, it is obvious that a model of the profile calculation is consistent one if all the aforementioned corrections are simultaneously included. Such calculations are planned in the future paper. A statistics of the octupole inhomogeneity tensor in a plasma is necessarily needed in the first step of such calculations. For the first time the distribution functions of the octupole inhomogeneity have been calculated in this paper using the Mayer-Mayer cluster expansion method similarly as for the quadrupole function in the paper [J. Halenka, Z. Phys. D 16, 1 (1990)]. The quantity is the reduced scale of the micro field strength, where is the Holtsmark normal field and is the mean distance defined by the relationship, that is approximately equal to the mean ion-ion distance; whereas is the screening parameter, where is the electronic Debye radius. (author)

2005-09-06

292

Effects of positive-parity states octupole correlations for even-even nuclei in rotational regions  

International Nuclear Information System (INIS)

Within the framework of the Usdpf (16) interacting boson model, effects of the octupole degree of freedom p-and f-bosons on the positive-parity states of even-even nuclei in rotational regions are discussed. it is shown that configurations of an even number of p-and f-bosons not only can be incorporated into the usual ground state band, ?-, ?-vibrational bands, but also naturally form the K? = 1+ and 3+ rotational bands ect. This result is similar to that of the U-sdg (15)-IBM. Besides, E2 transition probabilities are discussed briefly

1994-05-01

293

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

294

Spectroscopy on a single trapped 137Ba+ ion for nuclear magnetic octupole moment determination  

CERN Document Server

We present precision measurements of the hyperfine splittings in the 5D3/2 manifold of a single trapped Barium ion, 137Ba+ . Measurements of the hyperfine splittings are made between mF = 0 sublevels over a range of magnetic fields allowing us to interpolate to the zero field splittings with an accuracy below 10 Hz. Our results, in conjunction with theoretical calculations, allow the determination of the hyperfine coupling constant, C, with an accuracy below 0.1 Hz. This gives a subsequent determination of the nuclear magnetic octupole moment with an uncertainty limited almost completely by the accuracy of theoretical calculations.

Lewty, Nicholas C; Cazan, Radu; Barrett, M D

2012-01-01

295

Influence of severe plastic deformation on the structure and properties of ultrahigh carbon steel wire  

Energy Technology Data Exchange (ETDEWEB)

Ultrahigh-carbon steel wire can achieve very high strength after severe plastic deformation, because of the fine, stable substructures produce. Tensile strengths approaching 6000 MPa are predicted for UHCS containing 1.8%C. This paper discusses the microstructural evolution during drawing of UHCS wire, the resulting strength produced and the factors influencing fracture. Drawing produces considerable alignment of the pearlite plates. Dislocation cells develop within the ferrite plates and, with increasing strain, the size normal to the axis ({lambda}) decreases. These dislocation cells resist dynamic recovery during wire drawing and thus extremely fine substructures can be developed ({lambda} < 10 nm). Increasing the carbon content reduces the mean free ferrite path in the as-patented wire and the cell size developed during drawing. For UHCS, the strength varies as {lambda}{sup {minus}5}. Fracture of these steels was found to be a function of carbide size and composition. The influence of processing and composition on achieving high strength in these wires during severe plastic deformation is discussed.

Leseur, D R; Sherby, O D; Syn, C K

1999-07-01

296

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-06-25

297

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

298

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

299

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

International Nuclear Information System (INIS)

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

2010-12-23

300

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

Science.gov (United States)

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

Quesne, Christiane

2010-12-01

 
 
 
 
301

Some Properties of an Infinite Family of Deformations of the Harmonic Oscillator  

CERN Document Server

In memory of Marcos Moshinsky, who promoted the algebraic study of the harmonic oscillator, some results recently obtained on an infinite family of deformations of such a system are reviewed. This set, which was introduced by Tremblay, Turbiner, and Winternitz, consists in some Hamiltonians $H_k$ on the plane, depending on a positive real parameter $k$. Two algebraic extensions of $H_k$ are described. The first one, based on the elements of the dihedral group $D_{2k}$ and a Dunkl operator formalism, provides a convenient tool to prove the superintegrability of $H_k$ for odd integer $k$. The second one, employing two pairs of fermionic operators, leads to a supersymmetric extension of $H_k$ of the same kind as the familiar Freedman and Mende super-Calogero model. Some connection between both extensions is also outlined.

Quesne, C

2010-01-01

302

Effect of hydrogen and plastic deformation on certain properties of hydrogenized tantalum  

International Nuclear Information System (INIS)

Electric resistance, magnetic susceptibility and coefficient of thermal e.d.f. of samples with hydrogen content of 0-10 at.% in the range from 77 to 300 K are studied. Inflections in the region of phase transition are observed on temperature dependences of electric resistance and thermal e.d.f.. A conclusion is made that these effects are conditioned by hydrogen redistribution. The charge value of hydrogen atom does not change at that. It is found that plastic deformation increases hydrogen solubility. The effect is explained by the action of two mechanisms, namely, by the hydrogen concentration decrease in lattice at transition of a part of its atoms on dislocations, and by action of elastic stresses influencing the energy and growth of hydride inclusion

1980-01-01

303

Microstructural Evolution and Mechanical Property of AA5050 Alloy Deformed by Accumulative Roll Bonding  

Science.gov (United States)

In this study, ultrafine-grained AA5050 sheets were fabricated by the accumulative roll bonding (ARB) process. Transmission electron microscope observations showed that at the early stage of ARB, the grain size was reduced in the normal direction and became elongated along the rolling direction. The elongated grains were cut out by dense dislocations, which then tangled and condensed, resulting in the formation of dislocation cells. As the deformation proceeded, the dislocation cells evolved to sub-grain boundaries and then grain boundaries. The ultrafine-grained microstructure was obtained via four ARB cycles. The tensile tests at 473 K and 523 K (200 °C and 250 °C) showed large elongations for strain rates of 1 × 103 s-1 and 1 × 104 s-1.

Cheng, Kuiyu; Lu, Cheng; Tieu, Kiet; Zhu, Hongtao

2014-04-01

304

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.

2012-08-01

305

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

Science.gov (United States)

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

Tian, Xiaobo

2014-05-01

306

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

307

Analysis of the mechanical properties and deformation behavior of nanostructured commercially pure Al processed by equal channel angular pressing (ECAP)  

Energy Technology Data Exchange (ETDEWEB)

In the present paper commercially pure Al was processed by equal channel angular pressing (ECAP) up to 8 passes using route B{sub C}. For ECAP processing a proper die set was designed and constructed. Transmission electron microscope (TEM) and electron backscatter diffraction (EBSD) were used to evaluate the microstructure of the pressed materials. Mechanical properties and the deformation behavior of the ECAP processed material were investigated by the hardness and compression tests. The significant increase in hardness and yield stress after ECAP was discussed by two strengthening mechanisms. Based on these mechanisms, variations of the hardness and yield stress as a function of the pass numbers were related to the calculated dislocation densities and the average boundary spacing. Also it was suggested that the absorption of the dislocations into grain boundaries would be an effective recovery process for the absence of the strain hardening.

Reihanian, M.; Ebrahimi, R. [Department of Materials Science and Engineering, School of Engineering, Shiraz University, Shiraz (Iran, Islamic Republic of); Tsuji, N. [Department of Adaptive Machine Systems, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Moshksar, M.M. [Department of Materials Science and Engineering, School of Engineering, Shiraz University, Shiraz (Iran, Islamic Republic of)], E-mail: moshksar@shirazu.ac.ir

2008-01-25

308

Analysis of the mechanical properties and deformation behavior of nanostructured commercially pure Al processed by equal channel angular pressing (ECAP)  

International Nuclear Information System (INIS)

In the present paper commercially pure Al was processed by equal channel angular pressing (ECAP) up to 8 passes using route BC. For ECAP processing a proper die set was designed and constructed. Transmission electron microscope (TEM) and electron backscatter diffraction (EBSD) were used to evaluate the microstructure of the pressed materials. Mechanical properties and the deformation behavior of the ECAP processed material were investigated by the hardness and compression tests. The significant increase in hardness and yield stress after ECAP was discussed by two strengthening mechanisms. Based on these mechanisms, variations of the hardness and yield stress as a function of the pass numbers were related to the calculated dislocation densities and the average boundary spacing. Also it was suggested that the absorption of the dislocations into grain boundaries would be an effective recovery process for the absence of the strain hardening

2008-01-25

309

A 3D-RBS study of irradiation-induced deformation and masking properties of ordered colloidal nanoparticulate masks  

Science.gov (United States)

The 500 keV Xe 2+ irradiation-induced anisotropic deformation of ordered colloidal silica nanoparticulate masks is followed using 2 MeV 4He + Rutherford Backscattering Spectrometry (RBS) with different measurement geometries and the improved data analysis capabilities of the RBS-MAST spectrum simulation code. The three-dimensional (3D) geometrical transformation from spherical to oblate ellipsoidal and polygonal shape and the decrease of the mask's hole size is described. The masking properties of the silica monolayer and the depth distribution of Xe in the underlying Si substrate vs. the irradiated Xe 2+ fluence are discussed. Field Emission Scanning Electron Microscopy (FESEM) is applied as complementary characterization tool. Our results give contribution to clarify the impact of ion-nanoparticle interactions on the potentials and limits of nanosphere lithography. We also show the capability of the conventional RBS technique to characterize laterally ordered submicron-sized three-dimensional structures.

Zolnai, Z.; Deák, A.; Nagy, N.; Tóth, A. L.; Kótai, E.; Battistig, G.

2010-01-01

310

A 3D-RBS study of irradiation-induced deformation and masking properties of ordered colloidal nanoparticulate masks  

International Nuclear Information System (INIS)

The 500 keV Xe2+ irradiation-induced anisotropic deformation of ordered colloidal silica nanoparticulate masks is followed using 2 MeV 4He+ Rutherford Backscattering Spectrometry (RBS) with different measurement geometries and the improved data analysis capabilities of the RBS-MAST spectrum simulation code. The three-dimensional (3D) geometrical transformation from spherical to oblate ellipsoidal and polygonal shape and the decrease of the mask's hole size is described. The masking properties of the silica monolayer and the depth distribution of Xe in the underlying Si substrate vs. the irradiated Xe2+ fluence are discussed. Field Emission Scanning Electron Microscopy (FESEM) is applied as complementary characterization tool. Our results give contribution to clarify the impact of ion-nanoparticle interactions on the potentials and limits of nanosphere lithography. We also show the capability of the conventional RBS technique to characterize laterally ordered submicron-sized three-dimensional structures.

2010-01-01

311

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

Science.gov (United States)

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

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

2012-09-01

312

q-deformed KZB heat equation completeness, modular properties and SL(3,Z)  

CERN Document Server

We study the properties of one-dimensional hypergeometric integral solutions of the q-difference ("quantum") analogue of the Knizhnik-Zamolodchikov-Bernard equations on tori. We show that they also obey a difference KZB heat equation in the modular parameter, give formulae for modular transformations, and prove a completeness result, by showing that the associated Fourier transform is invertible. These results are based on SL(3,Z) transformation properties parallel to those of elliptic gamma functions.

Felder, G; Felder, Giovanni; Varchenko, Alexander

2001-01-01

313

Geometrical and physical properties of the 1982-84 deformation source at Campi Flegrei - Italy  

Science.gov (United States)

Deformation of the ground surface in volcanic areas is generally recognized as a reliable indicator of unrest, possibly resulting from the intrusion of fresh magma within the shallow rock layers. The intrusion process is usually represented by a deformation source such as an ellipsoidal pressurized cavity, embedded within a homogeneous and elastic half-space. Similar source models allow inferring the depth, the location and the (incremental) volume of the intrusion, which are very important parameters for volcanic risk implications. However, assuming a homogeneous and elastic rheology and, assigning a priori the shape and the mechanism of the source (within a very restricted 'library' of available solutions) may bias considerably the inference of source parameters. In complete generality, any point source deformation, including overpressure sources, may be described in terms of a suitable moment tensor, while the assumption of an overpressure source strongly restricts the variety of allowable moment tensors. In particular, by assuming a pressurized cavity, we rule out the possibility that either shear failure may precede magma emplacement (seismically induced intrusion) or may accompany it (mixed tensile and shear mode fracture). Another possibility is that a pre-existent weakness plane may be chosen by the ascending magma (fracture toughness heterogeneity). We perform joint inversion of levelling and EDM data (part of latter are unpublished), collected during the 1982-84 unrest at Campi Flegrei caldera: a 43% misfit reduction is obtained for a general moment source if the elastic heterogeneities computed from seismic tomography are accouted for. The inferred source is at 5.2 km depth but cannot be interpreted as a simple pressurized cavity. Moreover, if mass conservation is accounted for, magma emplaced within a shallow source must come from a (generally deeper) reservoir, which is usually assumed to be deep enough to be simply neglected. At Campi Flegrei, seismic tomography indicates that the 'deep' magma source is rather shallow (at 7-8 km depth), so that its presence should be included in any thorough attempt to source modeling. Taking into account a deflating source at 7.5 km depth (represented either as a horizontal sill or as an isotropic cavity) and an inflating moment source, the fit of both levelling and EDM data improves further (misfit reduction 80%), but still the best fitting moment source (at 5.5 km depth) falls outside the range of pressurized ellipsoidal cavities. The shallow moment source may be decomposed in a tensile and a shear dislocation. No clue is obtained that the shear and the tensile mechanisms should be located in different positions. Our favourite interpretation is in terms of a crack opening in mixed tensile and shear mode, as would be provided by fluid magma unwelding pre-stressed solid rock. Although this decomposition of the source is not unique, the proposed solution is physically motivated by the minimum overpressure requirement. An important implication of this new interpretation is that the magma emplaced in the shallow moment source during the 1982-84 unrest was not added to already resident magma at the same position.

Bonafede, Maurizio; Trasatti, Elisa; Giunchi, Carlo; Berrino, Giovanna

2010-05-01

314

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

International Nuclear Information System (INIS)

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

2012-08-01

315

THE 3D-MODEL OF RAT’S HUMERI TESTING TOUGHNESS PROPERTIES FOR VARIOUS DEFORMATION  

Directory of Open Access Journals (Sweden)

Full Text Available The article is devoted to study toughness of rat’s humeri testing them for stiffness, strength and stretching. Our aim is to create a 3D-model of the long bone for rats of different age. This model will allow conducting numerous toughness tests by changing the initial parameters. The portable experimental unit was used to test humeri stretching, with the measuring scale accurate to 0.25 kg. Evaluation of toughness was carried by Pro/Engineer software package (PTC, USA and included Pro/Mechanica modulus. The minimal value of critical toughness was measured in the bones of sucking rats. Value of stretching showed almost directly proportional dependence between critical bone toughness and rat’s age. Having compared experimental data and calculations of crack load values, we pointed that value deviation is less than 7 %. The 3-D image of the long bone for rats of different age can be frequently used for various deformation influences and with different initial parameters of the bone tissue.

Bushtruk A. N.

2013-12-01

316

Small deformation rheological properties of single and mixed Maltodextrin - Milk protein systems  

DEFF Research Database (Denmark)

Small deformation dynamic oscillation was used to investigate the structural behaviour of conformationally dissimilar maltodextrin and milk protein macro-molecules in a mixture, with the view of identifying the state of phase separation and the pattern of solvent distribution between the two constituent phases. The enthalpic nature of the maltodextrin network produced a sigmoidal transition in the development of storage modulus (G') during cooling and substantial thermal hysteresis upon heating of the gel. By contrast, the entropically-driven build up of structure in milk protein samples yielded linear and overlapping cooling and heating scans of G' with networks reverting into solutions at relatively low temperatures. These differences in the viscoelastic functions of the two polymers in combination with theoretical analysis (isostress-isostrain models, Kerner equation) have documented the reinforcing effect of strong and spherical maltodextrin inclusions on the weaker and continuous milk protein phase. However, at concentrations of maltodextrin beyond the phase inversion point, the binary assembly comprises a strong and continuous maltodextrin network surrounding the weaker milk protein inclusions. Finally, the sharp change in the pattern of water partition between the two polymeric components, as a result of phase inversion in the system, was rationalised on the basis of kinetically-influenced co-gels comprising phase separated networks which are trapped away from the state of thermodynamic equilibrium. Copyright (C) 1996 Published by Elsevier Science Ltd.

Chronakis, Ioannis S.; Kasapis, I.S.

1996-01-01

317

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

318

Mechanical properties and deformation behavior of as-cast Ti-Sn alloys  

International Nuclear Information System (INIS)

In this study, the mechanical properties of as-cast Ti-Sn alloys with Sn content ranging from 1 to 30 wt.% prepared using a dental cast machine were investigated and compared with commercially pure titanium (c.p. Ti), which was used as a control. Experimental results indicated that the diffraction peaks of all the Ti-Sn alloys matched those for ? Ti, and no ? phase peaks or any intermediate phases were found. All the Ti-Sn alloys had higher bending strengths, bending moduli and elastic recovery angles than those of c.p. Ti. For example, the bending strength of the Ti-1Sn alloy was higher than that of c.p. Ti by 68%, its bending modulus was higher than that of c.p. Ti by 43% and its elastically recoverable angle was higher than that of c.p. Ti by as much as 240%. Additionally, the Ti-1Sn, Ti-5Sn and Ti-10Sn alloys exhibited ductile properties. When the Sn content was 20 wt.% or greater, the alloys showed brittle properties. Our research suggested that Ti-1Sn alloy had the most favorable mechanical properties of all the metals in this study, making it the best candidate for prosthetic dental applications.

2009-06-24

319

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

Science.gov (United States)

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

Moghazy, Samir F.; McNair, Kevin C.

1996-01-01

320

A deformable shell model study of the properties of CsCl  

International Nuclear Information System (INIS)

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

1978-12-27

 
 
 
 
321

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

Directory of Open Access Journals (Sweden)

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

W. Ozgowicz

2008-07-01

322

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2008-05-16

323

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

324

Enhanced magnetic properties and bending strength of hot deformed Nd-Fe-B magnets with Cu additions  

International Nuclear Information System (INIS)

Commercial rapidly-quenched Nd-Fe-B ribbons blended with fine Cu powders (10-30 ?m) were hot pressed to obtain fully dense magnets and then die upset into highly anisotropic, oriented magnets. The effects of Cu addition on the magnetic properties and bending strength of hot deformed Nd-Fe-B magnets were investigated. It was found that the coercivity (Hcj) and maximum energy product (BH)max as well as the bending strength were enhanced significantly by Cu addition. Detailed microstructural investigations were carried out by transmission electron microscopy/high-resolution transmission electron microscopy (TEM/HRTEM). It shows that there are two types of grain boundaries in Cu-doped magnet, one is parallel and the other is trigonal. However, energy dispersive X-rays (EDX) analyses indicate that the two type intergranular phases are NdCu2. Analyses indicate that the enhanced texture of Cu-doped magnet is due to the lower melting point of the intergranular phase, leading to the enhancement in magnetic properties. Improvement of bending stress in Cu-doped magnet is related to the trigonal grain boundaries and the rheology of the intergranular phase.

2010-02-18

325

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

2011-06-01

326

Mechanical properties of severely deformed ZA-27 alloy using equal channel angular extrusion  

Energy Technology Data Exchange (ETDEWEB)

As cast ZA-27 alloy was subjected to equal channel angular extrusion (ECAE) with up to four passes using three different processing routes, and its mechanical properties (strength, hardness, ductility and extrusion load) were evaluated. The changes in the microstructure were also investigated. The ECAE was found to be quite effective in enhancing the mechanical properties of ZA-27 alloy. The strength and hardness of the alloys increased after the first ECAE pass followed by a gradual decrease with further passes for all processing routes. The elongation to failure, however, exceptionally increased with increase in the number of passes for all processing routes. Combined high strength and good ductility were obtained in the alloy after the first pass. The strength and maximum extrusion load showed similar trends with the number of passes for all processing routes. (author)

Purcek, G.; Altan, B.S.; Miskioglu, I.; Patil, A.

2005-09-15

327

On the relationship between large-deformation properties of wheat flour dough and baking quality  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Baking performance for bread and puff pastry was tested for Six European and two Canadian wheat cultivars and related to the rheological and fracture properties in uniaxial extension of optimally mixed flour-water doughs and doughs to which a mix of bakery additives was added. Extensive baking tests were performed as a function of water addition for puff pastry and as a function of water addition and mixing time for bread. For optimum baking performance, puff pastry doughs required lower wate...

Sliwinski, E. L.; Kolster, P.; Vliet, T.

2004-01-01

328

Non-yrast bands in a coherent quadrupole-octupole model  

International Nuclear Information System (INIS)

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. The energies are calculated from an analytically known formula in which for the first time we consider states with arbitrary large quantum numbers, allowing, as a new feature, to describe higher lying bands. A fit of the model parameters is performed for each nucleus in order to reach the best agreement with the experiment. The mass dependence of the parameters will be discussed. The model reproduces the structure of the spectra together with the observed B(E1), B(E2) and B(E3) reduced transition probabilities in the considered nuclei 152,154Sm, 154,156,158Gd, 236U and 100Mo. Aided by HIC for FAIR.

2012-03-19

329

Near-yrast spectroscopy of 164Yb and neighbouring nuclei: Systematics of octupole bands and bandcrossings  

International Nuclear Information System (INIS)

High-spin states in 164Yb have been populated in the 152Sm(16O,4n) and 150Sm(18O,4n) reactions. From studies of ?? coincidences, ?-ray angular distributions and conversion electron measurements the level scheme has been constructed. The g-band and the S-band have been established to spin and parity 22+ and 26+', respectively, and the rotational sequences (?,?)=(-,1)1, (-,0)1 and (-,0)2 to 23-, 24- and 18-, respectively. Constructed two-quasineutron configurations and cranked shell model calculations are compared with the experimental results. Residual interactions between quasiparticles are extracted from data. The side-bands in sup(162,164)Er and sup(164,166)Yb are discussed, putting a special emphasis on the octupole bands and their interaction with the two-quasiparticle bands. Crossing frequencies and the gain in alignment are summarized for the Yb isotopes and the main features are discussed. (orig.)

1986-02-24

330

Octupole magnet for soft X ray magnetic dichroism experiments: Design and performance  

International Nuclear Information System (INIS)

An octupole magnet endstation for soft x-ray magnetic dichroism measurements has been developed at the Advanced Light Source. The system consists of an eight pole electromagnet that surrounds a small vacuum chamber. The magnet provides fields up to 0.9 T that can be applied in any direction relative to the incoming x-ray beam. High precision magnetic circular and linear dichroism spectra can be obtained reversing the magnetic field for each photon energy in an energy scan. Moreover, the field dependence of all components of the magnetization vector can be studied in detail by choosing various angles of x-ray incidence while keeping the relative orientation of magnetic field and sample fixed

2003-08-25

331

Octupole Magnet For Soft X Ray Magnetic Dichroism Experiments: Design and Performance  

International Nuclear Information System (INIS)

An octupole magnet endstation for soft x ray magnetic dichroism measurements has been developed at the Advanced Light Source. The system consists of an eight pole electromagnet that surrounds a small vacuum chamber. The magnet provides fields up to 0.9 T that can be applied in any direction relative to the incoming x ray beam. High precision magnetic circular and linear dichroism spectra can be obtained reversing the magnetic field for each photon energy in an energy scan. Moreover, the field dependence of all components of the magnetization vector can be studied in detail by choosing various angles of x ray incidence while keeping the relative orientation of magnetic field and sample fixed

2004-05-12

332

Octupole magnet for soft X ray magnetic dichroism experiments: Design and performance  

Energy Technology Data Exchange (ETDEWEB)

An octupole magnet endstation for soft x-ray magnetic dichroism measurements has been developed at the Advanced Light Source. The system consists of an eight pole electromagnet that surrounds a small vacuum chamber. The magnet provides fields up to 0.9 T that can be applied in any direction relative to the incoming x-ray beam. High precision magnetic circular and linear dichroism spectra can be obtained reversing the magnetic field for each photon energy in an energy scan. Moreover, the field dependence of all components of the magnetization vector can be studied in detail by choosing various angles of x-ray incidence while keeping the relative orientation of magnetic field and sample fixed.

Arenholz, Elke; Prestemon, Soren O.

2003-08-24

333

Octupole Magnet For Soft X Ray Magnetic Dichroism Experiments: Design and Performance  

Science.gov (United States)

An octupole magnet endstation for soft x ray magnetic dichroism measurements has been developed at the Advanced Light Source. The system consists of an eight pole electromagnet that surrounds a small vacuum chamber. The magnet provides fields up to 0.9 T that can be applied in any direction relative to the incoming x ray beam. High precision magnetic circular and linear dichroism spectra can be obtained reversing the magnetic field for each photon energy in an energy scan. Moreover, the field dependence of all components of the magnetization vector can be studied in detail by choosing various angles of x ray incidence while keeping the relative orientation of magnetic field and sample fixed.

Arenholz, Elke; Prestemon, Soren O.

2004-05-01

334

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

335

Mechanical and service properties of low carbon steels processed by severe plastic deformation  

Directory of Open Access Journals (Sweden)

Full Text Available The structure and properties of the 0,09% C-Mn-Si-Nb-V-Ti, 0,1% C-Mn-V-Ti and 0,09% C-Mo-V-Nb low-carbon steels were studied after cold equal-channel angular pressing (ECAP. ECAP leads to the formation of partially submicrocrystalline structure with a grain size of 150 – 300 nm. The submicrocrystalline 0,09% C-Mn-Si-Nb-V-Ti steel compared with the normalized steel is characterized by Re higher more than by a factor of 2 and by the impact toughness higher by a factor of 3,5 at a test temperature of -40°C. The plasticity in this case is somewhat lower. The high-strength state of the submicrocrystalline 0,1% C-Mn-V-Ti and 0,09% C-Mo-V-Nb steels after ECAP is retained up to a test temperature of 500°C. The strength properties at 600°C (i.e. the fire resistance of these steels are higher by 20-25% as compared to those of the undeformed steels. The strength of the 0,09% C-Mo-V-Nb steel at 600°C is substantially higher than that of the 0,1% C-Mn-V-Ti steel.

J. Zrnik

2009-07-01

336

Microstructure and Mechanical Properties of Nanostructured and Ultrafine-Grained Titanium and the Zirconium Formed by the Method of Severe Plastic Deformation  

Science.gov (United States)

Results of investigation of the microstructure, mechanical properties, and thermostability of bioinert titanium VT1-0 and zirconium E110 in nanostructured and ultrafine-grained states formed by combined methods of severe plastic deformation, including abc pressing in a press-mould or without it and multipass rolling in grooved or smooth rolls, are presented. It is demonstrated that the combined severe plastic deformation method allows titanium and zirconium billets in nanostructured and ultrafine-grained states to be obtained that provides substantial improvement of the mechanical properties comparable to the properties of titanium alloys, for example, VT6 and VT16 ones. The yield strength and the microhardness of titanium and zirconium obey the Hall-Petch relationship.

Sharkeev, Yu. P.; Eroshenko, A. Yu.; Danilov, V. I.; Tolmachev, A. I.; Uvarkin, P. V.; Abzaev, Yu. A.

2014-02-01

337

When Colloids Can Deform  

Science.gov (United States)

Most colloidal systems that have been explored so far are hard-spheres, which limits their phase behavior and other physical properties to be not so rich as atomic and molecular systems. Here we present a new class of soft and deformable microgel colloidal particles with thermo-sensitivity and ability to display autonomous oscillation when driven by special fuels. The deformability, size changes and structure formation of micron-sized poly(NiPAM) particles and dumbbells of polystyrene-poly(NiPAM) interpenetrating networks can be imaged in situ and analyzed. Other mechanical and other physical properties attributable to deformability can be measured.

Zhang, Jie; Yu, Changqian; Bae, Sung Chul; Granick, Steve

2013-03-01

338

Influence of cementation on the deformation properties of bentonite/quartz buffer substance  

International Nuclear Information System (INIS)

Cementation, e.g.precipitation of crystalline or solid amorphous inorganic substance between individual grains, greatly affects the mechanical properties of fine-grained soils. As concerns the buffer mass with the composition suggested (10 weight percent bentonite and 90% quartz particles) the intergranular contact pressure between the quartz particles will not be able to cause 'pressure solution'. Also, the other possible cementation effects will be negligible with the exception of the process which leads to precipitation of SiO_2 dissolved from quartz particles and enriched in the interstitial pore space. This process and its consequences will be treated in this report. The nature of silica solution and precipitation is not known in detail. The chemical environment, temperature, pH and ion strength are known to be controlling factors which combine to make possible alternating solution and precipitation of silica. However, as shown by the case survey and the presented theoretical treatment the amount of precipitated SiO_2 will not be able to produce a brittle behaviour of the buffer mass even after thousands of years

1977-01-01

339

Morphology and magnetic properties of SmCo3/?-Fe nanocomposite magnets prepared via severe plastic deformation  

Science.gov (United States)

We report bulk SmCo3/?-Fe nanocomposite magnets prepared via high energy ball milling and warm compaction. The evolution of structure and magnetic properties with soft phase fraction have been systematically studied. Microstructural studies revealed that grain size of the nanocomposite magnets can be controlled below 20 nm with a homogeneous distribution of ?-Fe phase in the matrix of hard magnetic SmCo3 phase after severe plastic deformation. The refinement of the hard and soft phases morphology in nanoscale leads to effective inter-phase exchange coupling that gives rise to single-phase-like demagnetization behavior with enhanced remanence and maximum energy product (BH)max. The (BH)max up to 13.5 MGOe in the isotropic SmCo3/?-Fe nanocomposites with 25 wt. % of the soft phase has been obtained. Magnetic characterization at elevated temperatures shows that the nanocomposite SmCo3/?-Fe magnets have improved energy product compared to the single-phase SmCo3 magnets.

Poudyal, Narayan; Xia, Weixing; Yue, Ming; Ping Liu, J.

2014-05-01

340

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

Science.gov (United States)

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

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

2014-04-01

 
 
 
 
341

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

Science.gov (United States)

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

Pichaud, B.; Regula, G.; Yakimov, E. B.

2014-02-01

342

Comment on open-quote open-quote Double-octupole excitations in the N=84 nuclei 144Nd and 146Sm close-quote close-quote  

International Nuclear Information System (INIS)

Results of proton and electron inelastic scattering suggest that the interpretation of the 51--71--91- sequence in 144Nd as simple quadrupole-octupole-coupled states neglects large ?(f7/2i13/2)5,7,9 components and, therefore, that the interpretation of the 12+ state at 4354 keV as a double-octupole-phonon state (61+circle-times octupole circle-times octupole) given by Bargioni et al. [Phys. Rev. C 51, R1057 (1995)] may be too simple. It is suggested that measurements of the 91- state via single-neutron-stripping reactions and intermediate energy proton scattering can help determine the underlying structure of the 4354 keV state. copyright 1996 The American Physical Society

1996-04-01

343

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

International Nuclear Information System (INIS)

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

2007-07-01

344

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

345

Influence of deformation on the structure and mechanical and corrosion properties of high-nitrogen austenitic 07Kh16AG13M3 steel  

Science.gov (United States)

The correlation has been studied between the structure of a high-nitrogen austenitic Cr-Mn-N steel formed in the process of combined hardening treatment, including cold plastic deformation (CPD), and its mechanical and corrosion properties. The structure and properties of commercial high-nitrogen (0.8% N) 07Kh16AG13M3 steel is analyzed after rolling by CPD and aging at 500 and 800°C. It is shown that CPD of the steel occurs by dislocation slip and deformation twinning. Deformation twinning and also high resistance of austenite to martensitic transformations at true strains of 0.2 and 0.4 determine the high plasticity of the steel. The contribution of the structure imperfection parameters to the broadening of the austenite lines during CPD is estimated by X-ray diffraction. The main hardening factor is stated to be lattice microdistortions. Transmission electron microscopy study shows that heating of the deformed steel to 500°C leads to the formation of the intermediate CrN phase by a homogeneous mechanism, and the intermtallic ? phase forms along the austenite grain boundaries in the case of heating at 800°C. After hardening by all investigated technological schemes, exception for aging at 800°C, the steel does not undergo pitting corrosion and is slightly prone to a stress corrosion cracking during static bending tests, while aging at 800°C causes pitting corrosion at a pitting formation potential E pf = -0.25 V.

Berezovskaya, V. V.; Khadyev, M. S.; Merkushkin, E. A.; Sokolovskaya, Yu. A.

2013-11-01

346

Strong M1 components in 3-i?3-1 in nearly spherical nuclei: Evidence for isovector-octupole excitations  

International Nuclear Information System (INIS)

An evaluation of data obtained in (n,n'?) experiments reveals strong M1 3-i ? 3-1 transitions in nuclei near the N=50 (92Zr, 94Mo and 96Mo), Z=50 (112Cd and 114Cd) and N=82 (144Nd) shell closures. The observed left angle 31- M1 3i- right angle matrix elements scale with the left angle 21+ parallel M1 parallel 2+ms right angle matrix elements, and the energy difference between the initial 3-i state and the 3-1 octupole phonon is proportional to the left angle 3-1 parallel E3 parallel 0+gs right angle matrix element. The possibility of assigning the states of interest as octupole mixed-symmetry states is discussed.

2011-03-21

347

Self-assembly of an azobenzene-containing polymer prepared by a multi-component reaction: supramolecular nanospheres with photo-induced deformation properties.  

Science.gov (United States)

In this article, we have synthesized a polymer containing regulated azobenzene groups by one-pot multi-component polymerization (MCP) based on Passerini reaction, and investigated its self-assembly behavior and photo-induced deformation properties. We found that this molecule can form spherical structures with sizes ranging from hundreds of nanometers to several micrometers when dissolved in THF. NMR and FTIR studies indicate that there are associated hydrogen bonds among the molecules in the aggregates, which are responsible for the formation of the nanospheres. By controlling the stirring rate as the THF suspension is dropped into water, the nanospheres can be sorted according to their size. In this way, we have obtained nanospheres with relatively uniform diameter. When irradiated by UV light in the aqueous medium, the nanospheres tend to aggregate into large clusters, while in dry state they are ready to merge into island-like structures, showing a good photo-induced deformation property. PMID:24860850

Wang, Shuai; Zhang, Ning; Ge, Xiaopeng; Wan, Yingbo; Li, Xiaohong; Yan, Li; Xia, Yijun; Song, Bo

2014-07-21

348

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

Directory of Open Access Journals (Sweden)

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

W. Ozgowicz

2010-05-01

349

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

350

Confinement properties of high energy density plasmas in the Wisconsin levitated octupole  

International Nuclear Information System (INIS)

The confinement of particles and energy is critically dependent on the plasma-wall interaction. Results of a study detailing this interaction are presented. High power ICRF heated and gun afterglow plasmas were studied to detail the mechanisms determining particle and energy confinement. An extensive zero-D simulation code is used to assist in interpreting the experimental data. Physically reasonable models for plasma surface interactions, time dependent coronal treatment of impurities and multiple region treatment of neutrals are used in modeling the plasma. Extensive diagnostic data are used to verify the model. Non-heated plasmas decay from 28 to 3 eV allowing clear identification of wall impact energy thresholds for desorption and particle reflection. The charge state distribution of impurities verifies the reflux to plasma diffusion rate ratio. Close agreement between the simulation and experimental data is found

1984-01-01

351

'Windswept deformity'.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We describe 8 children with 'windswept deformity'--a valgus deformity of 1 knee in association with a varus deformity of the other. The disease is a physeal osteochondrosis and conservative treatment with serial corrective plaster casts is as effective as corrective osteotomies.

Oni, O. O.; Keswani, H.; Aganga, M. O.

1983-01-01

352

Preseismic and Postseismic Deformations Associated with Tohoku Earthquake and the Mechanical Properties of the Asthenosphere and of the Subduction Interface  

Science.gov (United States)

The postseismic and preseismic deformations preceding and following Tohoku earthquake have been recorded by the GPS stations of the GSI network and also far-field stations in far-East Russia, Korea and China. Using a 3D finite element model, we show that postseismic motions in the far-field can only be explained by relaxation in asthenosphere. We believe important to take into account this relaxation to interpret the data in the middle-field (over Japan). It can for example explain most of the postseismic velocities over southern Japan. However, the velocity pattern over Honshu, and in particular the postseismic uplift on the east coast of Honshu cannot be explained by this relaxation. Relaxation in a low viscosity wedge extending below the volcanic arc and viscous relaxation or aseismic slip on the bottom part of the interface are potential candidates for explaining uplift over the eastern part of Tohoku. While simple newtonian creep in a subduction channel and in the wedge or aseismic slip on the deep portions of the interface can both be compatible with the observed horizontal and vertical postseismic motions in front of the earthquake epicenter, the direction and large amplitude of motions further south (around 35°N) are only compatible with aseismic slip. This aseismic slip is going on since Tohoku earthquake and it clearly relaxes not only the stresses induced by Tohoku earthquake but rather stresses accumulated on the interface, at intermediate depths (around 45km depth), long before the megathrust earthquake which only triggered this aseismic slip. An interface with brittle asperities imbedded in a low viscosity material (serpentine?) are shown to have the appropriate properties to explain the observations, in particular to account for accumulation of stresses and relaxation on a time-scale of several years.

Trubienko, O.; Fleitout, L.; Garaud, J.; Shestakov, N.

2013-12-01

353

Carbon Deposition during Brittle Rock Deformation: Changes in Electrical Properties of Fault Zones and Potential Geoelectric Phenomena During Earthquakes.  

Science.gov (United States)

To investigate potential mechanisms for geoelectric phenomena accompanying earthquakes, we have deformed hollow cylinders of Sioux quartzite to failure in the presence of carbonaceous pore fluids and investigated the resulting changes in electrical conduc...

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

2008-01-01

354

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

International Nuclear Information System (INIS)

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

2010-07-25

355

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

356

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

357

Core breaking and octupole low-spin states in $^{207}$ Tl  

CERN Multimedia

We propose to study the low-spin level structure of the $^{207}$Tl nucleus populated by the beta decay of $^{207}$Hg. While $^{207}$Tl is a single-proton hole nucleus, the majority of the observed states will have threeparticle structure thus requiring the breaking of the neutron or proton core, or a collective octupole phonon coupled to the single proton hole. Thus information will be obtained on the single particle orbitals in the vicinity of the N=126 and Z=82 magic numbers, and on the size of the shell gap. The results will be used to improve the predictive power of the shell model for more exotic nuclei as we move to lighter N=126 nuclei.The experiment will use the ISOLDE Decay station, and will take advantage of the $^{207}$Hg beam from the molten lead target. A test on the feasibility to produce $^{208}$Hg beam from the same target, with the aim to study the beta-decay into $^{208}$Tl, could be performed at the same time.

358

Measuring the Nuclear Magnetic Octupole Moment of a Single Trapped Barium-137 Ion  

Science.gov (United States)

Recent measurements of hyperfine structure in the cesium-133 atom resolved a nuclear magnetic octupole moment ? much larger than expected from the nuclear shell model[1]. To explore this issue further, we are undertaking an experiment to measure the hyperfine structure in the 5D manifold of a single trapped barium-137 ion which, together with reliable calculations in alkali-like Ba^+, should resolve ? with sensitivity better than the shell model value [2]. We use a TmHo:YLF laser tuned to 2051 nm and a fiber laser tuned to 1762 nm to drive the 6S1/2 to 5D3/2 and 6S1/2 to 5D5/2 electric quadrupole transitions. These lasers allow us to selectively populate any hyperfine sub-level in the 5D manifold. We will then perform RF spectroscopy on the 5D states to make a precision measurement of the hyperfine frequency intervals. We report on the development of the laser and RF spectroscopy systems. [1] V. Gerginov, A. Derevianko, and C. E. Tanner, Phys. Rev. Lett. 91, 072501 [2] K. Beloy, A. Derevianko, V. A. Dzuba, G. T. Howell, B. B. Blinov, E. N. Fortson, arXiv:0804.4317v1 [physics.atom-ph] 28 Apr 2008

Kleczewski, Adam; Fortson, Norval; Blinov, Boris

2009-05-01

359

q-deformed Fermions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This is a study of $q$-Fermions arising from a q-deformed algebra of harmonic oscillators. Two distinct algebras will be investigated. Employing the first algebra, the Fock states are constructed for the generalized Fermions obeying Pauli exclusion principle. The distribution function and other thermodynamic properties such as the internal energy and entropy are derived. Another generalization of fermions from a different q-deformed algebra is investigated which deals with q...

Swamy, P. Narayana

2005-01-01

360

SEARCH FOR TWO-PHONON OCTUPOLE VIBRATIONAL BANDS IN 88, 89, 92, 93, 94, 96Sr AND 95, 96, 97, 98Zr  

Science.gov (United States)

Several new gamma transitions were identified in 94Sr, 93Sr, 92Sr, 96Zr and 97Zr from the spontaneous fission of 252Cf. Excited states in 88, 89, 92, 94, 96Sr and 95, 96, 97, 98Zr were reanalyzed and reorganized to propose the new two-phonon octupole vibrational states and bands. The spin and parity of 6+ are assigned to a 4034.5 keV state in 94Sr and 3576.4 keV state in 98Zr. These states are proposed as the two-phonon octupole vibrational states along with the 6+ states at 3483.4 keV in 96Zr, at 3786.0 keV in 92Sr and 3604.2 keV in 96Sr. The positive parity bands in 88, 94, 96Sr and 96, 98Zr are the first two-phonon octupole vibrational bands based on a 6+ state assigned in spherical nuclei. It is thought that in 94, 96Sr and 96, 98Zr a 3- octupole vibrational phonon is weakly coupled to an one-phonon octupole vibrational band to make the two-phonon octupole vibrational band. Also, the high spin states of odd-A95Zr and 97Zr are interpreted to be generated by the neutron 2d5/2 hole and neutron 1g7/2 particle, respectively, weakly coupled to one- and two-phonon octupole vibrational bands of 96Zr. The high spin states of odd-A87Sr are interpreted to be caused by the neutron 1g9/2 hole weakly coupled to 3- and 5- states of 88Sr. New one- and two-POV bands in 95, 97Zr and 87, 89Sr are proposed, for the first time, in the present work.

Hwang, J. K.; Hamilton, J. H.; Ramayya, A. V.; Brewer, N. T.; Wang, E. H.; Luo, Y. X.; Zhu, S. J.

2012-09-01

 
 
 
 
361

Collective motion in system with general multipolar-deformations  

International Nuclear Information System (INIS)

A general formalism is given for the collective motion in a system with general multipolar-deformations, which is treated as vibrations in body-fixed frame and rotation of whole system about the axes of Lab-system, as well as the coupling between vibrations and rotation. 18 various body - fixed frames are defined for octupole deformed system, which shows they can be put into 9 various classifies and the determinants of metric matrix in the body-fixed frames defined by the variables a30, a31, a32 , b31 and a30, a31, b31, b32 are 9a322 and 9b322, which are the simplest

2000-08-01

362

Microstructures and mechanical properties of pure copper deformed severely by equal-channel angular pressing and high pressure torsion  

Energy Technology Data Exchange (ETDEWEB)

Pure Cu of 99.98 wt.% purity has been processed at room temperature by diverse techniques of severe plastic deformation, namely equal-channel angular pressing (ECAP), high pressure torsion (HPT) and a combination of both in order to find out the evolution on the microstructural homogeneity for each of the processes and their combination. Starting with a grain size of {approx}60 {mu}m, severe plastic deformation has been introduced to the material while maintaining the sample dimensions unchanged through the processes of ECAP and HPT. A significant decrease in grain size was observed by transmission electronic microscopy (TEM). Microtensile and microhardness tests were carried out on the deformed material in the three processing conditions. A significant improvement of the tensile strength was promoted with admissible penalization on ductility.

Lugo, N. [Department of Materials Science and Metallurgical Engineering, ETSEIB, Polytechnic University of Catalonia, Av. Diagonal 647, 08028 Barcelona (Spain)], E-mail: nayar.lugo@upc.edu; Llorca, N. [Department of Materials Science and Metallurgical Engineering, University of Barcelona, C/Marti i Franques 1-11, 08028 Barcelona (Spain)], E-mail: nullorca@ub.edu; Cabrera, J.M. [Department of Materials Science and Metallurgical Engineering, ETSEIB, Polytechnic University of Catalonia, Av. Diagonal 647, 08028 Barcelona (Spain); CTM Technical Center, Av. Bases de Manresa 1, 08242 Manresa (Spain)], E-mail: jose.maria.cabrera@upc.edu; Horita, Z. [Department of Materials Science and Engineering, Faculty of Engineering, Kyushu University, Fukuoka 819-0395 (Japan)], E-mail: horita@zaiko.kyushu-u-ac.jp

2008-03-25

363

Microstructures and mechanical properties of pure copper deformed severely by equal-channel angular pressing and high pressure torsion  

International Nuclear Information System (INIS)

Pure Cu of 99.98 wt.% purity has been processed at room temperature by diverse techniques of severe plastic deformation, namely equal-channel angular pressing (ECAP), high pressure torsion (HPT) and a combination of both in order to find out the evolution on the microstructural homogeneity for each of the processes and their combination. Starting with a grain size of ?60 ?m, severe plastic deformation has been introduced to the material while maintaining the sample dimensions unchanged through the processes of ECAP and HPT. A significant decrease in grain size was observed by transmission electronic microscopy (TEM). Microtensile and microhardness tests were carried out on the deformed material in the three processing conditions. A significant improvement of the tensile strength was promoted with admissible penalization on ductility

2008-03-25

364

q -deformed statistical-mechanical property in the dynamics of trajectories en route to the Feigenbaum attractor  

Science.gov (United States)

We demonstrate that the dynamics toward and within the Feigenbaum attractor combine to form a q -deformed statistical-mechanical construction. The rate at which ensemble trajectories converge to the attractor (and to the repellor) is described by a q entropy obtained from a partition function generated by summing distances between neighboring positions of the attractor. The values of the q indices involved are given by the unimodal map universal constants, while the thermodynamic structure is closely related to that formerly developed for multifractals. As an essential component in our demonstration we expose, in great detail, the features of the dynamics of trajectories that either evolve toward the Feigenbaum attractor or are captured by its matching repellor. The dynamical properties of the family of periodic superstable cycles in unimodal maps are seen to be key ingredients for the comprehension of the discrete scale invariance features present at the period-doubling transition to chaos. Elements in our analysis are the following. (i) The preimages of the attractor and repellor of each of the supercycles appear entrenched into a fractal hierarchical structure of increasing complexity as period doubling develops. (ii) The limiting form of this rank structure results in an infinite number of families of well-defined phase-space gaps in the positions of the Feigenbaum attractor or of its repellor. (iii) The gaps in each of these families can be ordered with decreasing width in accordance with power laws and are seen to appear sequentially in the dynamics generated by uniform distributions of initial conditions. (iv) The power law with log-periodic modulation associated with the rate of approach of trajectories toward the attractor (and to the repellor) is explained in terms of the progression of gap formation. (v) The relationship between the law of rate of convergence to the attractor and the inexhaustible hierarchy feature of the preimage structure is elucidated. (vi) A "mean field" evaluation of the atypical partition function, a thermodynamic interpretation of the time evolution process, and a crossover to ordinary exponential statistics are given. We make clear the dynamical origin of the anomalous thermodynamic framework existing at the Feigenbaum attractor.

Robledo, A.; Moyano, L. G.

2008-03-01

365

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

2011-01-01

366

Description of low-lying vibrational K? ? 0+ states of deformed nuclei in the quasiparticle-phonon nuclear model  

International Nuclear Information System (INIS)

The QPNM equations are derived taking account of p-h and p-p interactions. The calculated quadrupole, octupole and hexadecapole vibrational states in 168Er, 172Yb and 178Hf are found to be reasonale agreement with experimental data. It is shown that distribution of the E? strength in some deformed nuclei differs from the standard one. There are cases when for a given K? and E? strength is concentrated not on the first but on higher-lying states. The assertion made earlier about the absence of collective two-phonon states in deformed nuclei is confirmed. 44 refs.; 1 fig.; 6 tabs

1989-01-01

367

Deformed Dynamics of Q-Deformed Systems  

International Nuclear Information System (INIS)

Quantum algebras have been the subject of an intensively research in the last years. Particularly, after the works of Macfarlane and Biedenharn on the q-deformed oscillators, a great effort has been devoted to the application and generalization of q-deformed systems in chemistry and physics. In quantum optics, q-bosons have been used to generalized fundamental models such as, the Jaynes-Cummings and Dicke models. Besides, using generalized deformed oscillators several versions of the Jaynes-Cummings Hamiltonian have found a unified description. In the present work, we study the dynamical properties of q-deformed oscillators and their relationship to the anharmonic oscillators by means of a Lie-algebraic approach. In doing so, we find that an infinite dimensional set of 'q-deformed relevant operators' close a 'partial q-deformed Lie algebra' under commutation with the Arik-Coon Hamiltonian. We show that the dynamics of the s?stem can be described in terms of the multi commutator of the type [H,... , [H, 0] . . .]. Eve also obtain, that the multi commutator can be expressed for q > 1 as an operator average with respect to the ('Binomial distribution' which depends on[g on the deformation parameter q, and for the general case (i.e. q - R) as a 'power law'. As a consequence of the power law dependence, we find that the dynamics of the infinite-dimensional q-deformed Lie-algebra scale, i.e. the temporal evolution for the whole set of relevant operators collapse on a single curve. We calculate and analyze, the temporal evolution of the set of relevant operators for the q-deformed and the anharmonic oscillator when the initial conditions are a q-coherent and coherent states respectively. We obtain that the dynamics of both models is governed by a weighted average with respect to the 'q-deformed Poisson' and the 'standard Poisson' distributions respectively. Finally, we find the conditions under which the dynamics of the relevant operators of both oscillators are isomorphous, and we conclude that q is not only related to the anharmonicity parameter but also depends on the index that characterizes the relevant operators

1999-03-18

368

Null Deformed Domain Wall  

CERN Document Server

We study null 1/4 BPS deformations of flat Domain Wall solutions (NDDW) in N=2, d=5 gauged supergravity with hypermultiplets and vector multiplets coupled. These are uncharged timedependent configurations and contain as special case, 1/2 supersymmetric flat domain walls (DW) and, as well, 1/2 BPS null solutions of the ungauged supergravity. Combining our analysis with the classification method initiated by Gauntlett et al., we prove that all the possible deformations of the DW have origin in the hypermultiplet sector or/and are null. Here, we classify all the null deformations: we show that they naturally organize in "gauging" (v-deformation) and "non gauging" (u-deformation). They have different properties: only in presence of v-deformation the solution is supported by a timedependent scalar potential. Furthermore we show that u-deformation forces the number of multiplets coupled to be different by one. We discuss the general procedure for constructing explicit solutions, stressing the crucial role taken by ...

Celi, A

2007-01-01

369

Null deformed domain wall  

International Nuclear Information System (INIS)

We study null 1/4 BPS deformations of flat domain wall solutions (NDDW) in N = 2, d = 5 gauged supergravity with hypermultiplets and vector multiplets coupled. These are uncharged time-dependent configurations and contain as special case, 1/2 supersymmetric flat domain walls (DW), as well as 1/2 BPS null solutions of the ungauged supergravity. Combining our analysis with the classification method initiated by Gauntlett et al., we prove that all the possible deformations of the DW have origin in the hypermultiplet sector or/and are null. Here, we classify all the null deformations: we show that they naturally organize themselves into 'gauging' (v-deformation) and 'non gauging' (u-deformation). They have different properties: only in presence of v-deformation is the solution supported by a time-dependent scalar potential. Furthermore we show that the number of possible deformations equals the number of matter multiplets coupled. We discuss the general procedure for constructing explicit solutions, stressing the crucial role taken by the integrability conditions of the scalars as spacetime functions. Two analytical solutions are presented. Finally, we comment on the holographic applications of the NDDW, in relation to the recently proposed time-dependent AdS/CFT

2007-02-01

370

q-Deformed Dynamics and Virial Theorem  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the framework of the q-deformed Heisenberg algebra the investigation of $q$-deformation of Virial theorem explores that q-deformed quantum mechanics possesses better dynamical property. It is clarified that in the case of the zero potential the theoretical framework for the q-deformed Virial theorem is self-consistent. In the selfadjoint states the q-deformed uncertainty relation essentially deviates from the Heisenberg one.

Zhang, Jian-zu

2002-01-01

371

Nanomechanical Properties and Deformation Behaviors of Multi-Component (AlCrTaTiZrNxSiy High-Entropy Coatings  

Directory of Open Access Journals (Sweden)

Full Text Available In this study multi-component (AlCrTaTiZrNxSiy high-entropy coatings were developed by co-sputtering of AlCrTaTiZr alloy and Si in an Ar/N2 mixed atmosphere with the application of different substrate biases and Si-target powers. Their nanomechanical properties and deformation behaviors were characterized by nanoindentation tests. Because of the effect of high mixing entropies, all the deposited multi-component (AlCrTaTiZrNxSiy high-entropy coatings exhibited a simple face-centered cubic solid-solution structure. With an increased substrate bias and Si-target power, their microstructures changed from large columns with a [111] preferred orientation to a nanocomposite form with ultrafine grains. The hardness, H/E ratio and H3/E2 ratio of (AlCrTaTiZrN1.07Si0.15 coating reached 30.2 GPa, 0.12 and 0.41 GPa, respectively, suggesting markedly suppressed dislocation activities and a very high resistance to wear and plastic deformation, attributable to grain refinements and film densification by the application of substrate bias, a nanocomposite structure by the introduction of silicon nitrides, and a strengthening effect induced by severe lattice distortions. In the deformed regions under indents, stacking faults or partial dislocations were formed, while in the stress-released regions, near-perfect lattices recovered.

Shao-Yi Lin

2013-12-01

372

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

Science.gov (United States)

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 for act-D2, D4, and D5 in AlGaN, and act-D2 and 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.; Stefa?ska-Skrobas, K.; Christensen, N. E.; Svane, A.

2013-08-01

373

Effect of one-axis deformation on Cd2Nb2O7 dielectric relaxation and pyroelectric properties in the 100-300 K temperature range  

International Nuclear Information System (INIS)

The effect of one-axis deformation on dielectric relaxation and pyroelectric properties of Cd2Nb2O7 in the 100-300 K temperature range is studied. For the first time a profound variation of the temperature dependence of permittivity and the pyroelectric coefficient of this compound when applying one-axis mechanical stress have been discovered. The obtained results have shown that in the 100-196 K temperature range Cd2Nb2O7 is a ferroelectric and a ferroelastic at the same time, and even small mechanical stress increases the upper boundary of the given range

1986-12-26

374

On the deformation of abelian integrals  

CERN Document Server

We consider the deformation of abelian integrals which arose from the study of SG form factors. Besides the known properties they are shown to satisfy Riemann bilinear identity. The deformation of intersection number of cycles on hyperelliptic curve is introduced.

Smirnov, F A

1995-01-01

375

Evaluating the effects of stress-driven segregation, strain and reaction history, and intrinsic rock properties on melt transport and rock rheology in the naturally deformed lithosphere  

Science.gov (United States)

The segregation, migration, and extraction of melt - and the emplacement and assembly of the melts as plutonic systems - are major controls on mass and heat transfer in the lithosphere. The distribution of partial melts at the grain scale, and partially molten rocks at larger spatial scales, exerts a profound influence on rock rheology, and is of significance for melt segregation, dynamic weakening, and strain localization at a variety of lithospheric levels. Evaluating the rheological effects of melt in the lithosphere requires insight into the relative effects of stress-driven segregation, strain and reaction history, and intrinsic rock properties of naturally deformed lithospheric sections. Melt segregation and distribution are dynamically linked at a variety of spatial scales to relative motion between the melt and solid phase in deforming partially molten rocks, which gives rise to an evolving melt topology and porosity-permeability structure. The extraction of melt from grain boundaries requires connectivity into a channelized migration network or through structural fabrics that allow for the horizontal and vertical transfer of melt in the crust, compelling examples of which have been demonstrated in migmatite-granite complexes in the crust, dike and vein networks in the crust and mantle, and for reactive melt migration pathways in the upper mantle. Numerical models and experimental rock deformation studies have provided important insights into the mechanisms of melt segregation, geometric characteristics of channelized melt migration networks, and the rheological consequences of melt mobilization. However, field-based and microstructural investigations of exhumed lithospheric sections remain critical for evaluating relationships between deformation and melt flow processes at geologically relevant scales, and under natural deformation conditions. For example, field-based studies in the Twin Sisters ultramafic complex (Washington State) document melt migration geometries that differ from patterns predicted by numerical and experimental studies of stress-driven melt segregation. Dunite melt bands in low strain regions of the Twin Sisters complex typically form high angle conjugate geometries, but in highly deformed portions of the host peridotites their geometries systematically become more subparallel. Structural and textural observations suggest that melt flow was contemporaneous with deformation and therefore the organization of the reactive melt flow network was dynamically linked to the magnitude of viscous strain and localization phenomena in the host peridotites. These observations underscore the importance of field, microstructural, and textural studies in tectonic systems that experienced the sequential or coeval effects of melt extraction, migration or accumulation (e.g., migmatite-granite complexes). The permeability of melt flow networks, the distribution of melt and melt connectivity in the orogenic crust, and the timing of partial melting relative to deformation, all affect the efficiency of melt transfer in the lithosphere. The rheological evolution of partially molten rocks further significantly affects the ability of the melt-rich crust to mobilize into zones of active deformation, such as during the formation of migmatite domes (e.g., the Naxos dome, Greece).

Kruckenberg, S. C.; Tikoff, B.

2012-12-01

376

Di-neutron correlation in soft octupole excitations of neutron-rich Ni isotopes beyond N=50  

CERN Document Server

We investigate low-lying octupole response of neutron-rich Ni isotopes beyond the N=50 shell closure using the Skyrme-Hartree-Fock-Bogoliubov mean-fields and the continuum quasi-particle random phase approximation. Performing detailed numerical analyses employing the Skyrme parameter set SLy4 and a density-dependent delta interaction of the mixed type, we show that a neutron mode emerges above the neutron separation energy as a consequence of the weak binding of neutrons and it exhibits strong influences of the di-neutron correlation.

Serizawa, Yasuyoshi

2008-01-01

377

Di-neutron correlation in soft octupole excitations of neutron-rich Ni isotopes beyond N=50  

International Nuclear Information System (INIS)

We investigate the low-lying octupole response of neutron-rich Ni isotopes beyond the N=50 shell closure using the Skyrme-Hartree-Fock-Bogoliubov mean fields and the continuum quasi-particle random phase approximation. Performing detailed numerical analyses employing the Skyrme parameter set SLy4 and a density-dependent delta interaction of the mixed type, we show that a neutron mode emerges above the neutron separation energy as a consequence of the weak binding of neutrons and that it strongly influences the di-neutron correlation. (author)

2009-01-01

378

Di-Neutron Correlation in Soft Octupole Excitations of Neutron-Rich Ni Isotopes beyond N = 50  

Science.gov (United States)

We investigate the low-lying octupole response of neutron-rich Ni isotopes beyond the N = 50 shell closure using the Skyrme-Hartree-Fock-Bogoliubov mean fields and the continuum quasi-particle random phase approximation. Performing detailed numerical analyses employing the Skyrme parameter set SLy4 and a density-dependent delta interaction of the mixed type, we show that a neutron mode emerges above the neutron separation energy as a consequence of the weak binding of neutrons and that it strongly influences the di-neutron correlation.

Serizawa, Y.; Matsuo, M.

2009-01-01

379

Giant resonance studies with medium energy 14N ions: excitation of the high-energy octupole resonance  

International Nuclear Information System (INIS)

Inelastic scattering of 50 MeV/A 14N Ions has been used to study the excitation of giant resonances with the aim of investigating the ''higher-l (''>=''3)'' modes. A simultaneous multi-peak, multi-spectrum analysis of the giant resonance region in 90Zr indicates four peaks evidently corresponding to the giant quadrupole resonance (GQR), a combination of the giant monopole resonance (ISGMR) and the isovector giant dipole resonance (IVGDR), the high-energy octupole resonance (HEOR), and the isoscalar giant dipole resonance (ISGDR). Similar strength in the HEOR region has also been observed in 116Sn. (Author)

1990-05-24

380

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

CERN Multimedia

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.

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

 
 
 
 
381

Melt-rock interactions, deformation, hydration and seismic properties in the sub-arc lithospheric mantle inferred from xenoliths from seamounts near Lihir, Papua New Guinea  

Science.gov (United States)

This study analyses the interactions between deformation and reactive fluid and melt percolation, and their effects on sub-arc mantle seismic properties based on microstructural observations on mantle xenoliths extracted by the Tubaf and Edison seamounts close to the Lihir Island, in the Papua New Guinea archipelago. These xenoliths sample an oceanic lithosphere, which has experienced high-temperature deformation in the presence of fluids or melts. This was followed by metasomatism under static conditions. Syn-kinematic percolation of reactive Si-rich melts or fluids in peridotites has produced pyroxene-enrichment, grain size reduction, and dispersion of olivine crystal preferred orientation (CPO). Fourier transform infrared spectroscopy analyses show that olivine has very low water contents (1-4 wt. ppm H2O), similar to spinel peridotites from other subduction zones. These low values may record both low water solubility in olivine at low pressure and dehydration during transport and exhumation. Water contents in pyroxenes are highly variable and likely result from spatially heterogeneous melt or fluid percolation. Analysis of olivine CPO indicates dominant activation of both (010)[100] and (001)[100] slip systems, which are characteristic of deformation under high temperature, low stress, low pressure and low to moderate hydrous conditions. Fast S-wave polarization and P- and Rayleigh propagation directions are thus parallel to the mantle flow direction. The pyroxene enrichment by melt-rock reactions is accompanied by dispersion of olivine CPO and induces a significant decrease of the maximum S-wave and P-wave anisotropy in the peridotites. The calculated seismic properties also show that the lowest Vp/Vs ratios (< 1.7) mapped in fore-arc mantle may only be explained by taking in consideration the CPO-induced elastic anisotropy of the peridotites.

Soustelle, Vincent; Tommasi, Andréa; Demouchy, Sylvie; Franz, Leander

2013-11-01

382

Classical-limit description of rotation-vibrational band excitation in deformed even-even nuclei  

International Nuclear Information System (INIS)

Classical-limit S-matrix (CLSM) theory, previously formulated for Coulomb excitation of the ground band in even-even nuclei, is extended to rotation-vibrational bands. A perturbation approximation is introduced for which the results are conceptually simple, and lend themselves to an illuminating classical description of rotational-vibrational excitation. Numerical calculations performed with this formalism for the K=0 octupole band in 238U are in good agreement with calculations based on the semiclassical Alder-Winther theory. It is suggested that methods analogous to those described here could be used to describe nucleon and cluster transfer in deformed systems. (Auth.)

1978-10-02

383

q-DEFORMED Phonons  

Science.gov (United States)

We make use of a recently identified distribution function for the q-deformed oscillators and apply it to the q-analog of phonons. The thermodynamic properties of such q-phonons and q-photons are derived and compared with the case of ordinary phonons.

Swamy, P. Narayana

384

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...

385

Properties of 12Be and 11Be in terms of single-particle motion in deformed potential  

CERN Multimedia

Inspired by the recent measurement of the B(E2;$0_{2}^{+} \\to 2_{1}^+$) and B(E0;$0_{2}^{+} \\to 0_{1}^+$) values in $^{12}$Be, we give an interpretation of available spectroscopic data on both $^{12}$Be and $^{11}$Be, using a simple model which contains the essential feature of these two nuclei; the presence of weakly-bound neutron(s) in deformed potentials. The agreement of the calculated results with observed data is surprisingly good, including well-known strong E1 transitions in both nuclei.

Hamamoto, I

2007-01-01

386

Deformation and electrical properties of magnetic and vertically conductive composites with a chain-of-spheres structure  

Science.gov (United States)

Vertically anisotropically conductive composites with aligned chain-of-spheres of 20-75 mm Ni particles in an elastomer matrix have been prepared by curing the mixture at 100°C-150°C under an applied magnetic field of ˜300-1000 Oe. The particles are coated with a ˜120 nm thick Au layer for enhanced electrical conductivity. The resultant vertically aligned but laterally isolated columns of conductive particles extend through the whole composite thickness and the end of the Ni columns protrude from the surface, contributing to enhanced electrical contact on the composite surface. The stress-strain curve on compressive deformation exhibits a nonlinear behavior with a rapidly increasing Young's modulus with stress (or pressure). The electrical contact resistance Rc decreases rapidly when the applied pressure is small and then more gradually after the applied pressure reaches 500 psi (˜3.4 MPa), corresponding to a 30% deformation. The directionally conductive elastomer composite material with metal pads and conductive electrodes on the substrate surface can be used as a convenient tactile shear sensor for applications involving artificial limbs, robotic devices, and other visual communication devices such as touch sensitive screens.

Choi, Chulmin; Hong, Soonkook; Chen, Li-Han; Liu, Chin-Hung; Choi, Duyoung; Kuru, Cihan; Jin, Sungho

2014-05-01

387

Deformations of large fundamental groups  

CERN Document Server

A projective variety has a large fundamental group if its universal covering has no compact subvarieties. In this paper we investigate whether the property of a variety having a large fundamental groups is stable under K\\"{a}hler deformations.

De Oliveira, B; Ramachandran, M

2001-01-01

388

Plastic deformation of indium nanostructures  

International Nuclear Information System (INIS)

Highlights: ? Indium nanopillars display two different deformation mechanisms. ? ?80% exhibited low flow stresses near that of bulk indium. ? Low strength nanopillars have strain rate sensitivity similar to bulk indium. ? ?20% of compressed indium nanopillars deformed at nearly theoretical strengths. ? Low-strength samples do not exhibit strength size effects. - Abstract: Mechanical properties and morphology of cylindrical indium nanopillars, fabricated by electron beam lithography and electroplating, are characterized in uniaxial compression. Time-dependent deformation and influence of size on nanoscale indium mechanical properties were investigated. The results show two fundamentally different deformation mechanisms which govern plasticity in these indium nanostructures. We observed that the majority of indium nanopillars deform at engineering stresses near the bulk values (Type I), with a small fraction sustaining flow stresses approaching the theoretical limit for indium (Type II). The results also show the strain rate sensitivity and flow stresses in Type I indium nanopillars are similar to bulk indium with no apparent size effects.

2011-07-25

389

One-phonon octupole vibrational states in {sup 211}At, {sup 212}Rn, {sup 213}Fr and {sup 214}Ra with N = 126  

Energy Technology Data Exchange (ETDEWEB)

Excited high spin states in {sup 211}At, {sup 212}Rn, {sup 213}Fr and {sup 214}Ra with N = 126 are reorganized and interpreted in terms of the stretched weak coupling of an octupole 3{sup -} phonon. Nearly identical sequences of levels with {Delta}I = 3 and the parity change are found, for the first time, up to 25{sup -} for 20 states of {sup 214}Ra, up to 35{sup -} for 36 states of {sup 212}Rn and up to 53/2{sup +} for 16 states of {sup 213}Fr. The stretched weak coupling of an octupole phonon is extended up to the highest excitation energy of 11355 keV for {sup 212}Rn which has the largest experimental B(E3) value of 44.1(88) W.u. for the 11{sup -} {yields} 8{sub 2}{sup +} transition. The stretched weak coupling of an octupole 3{sup -} phonon needs to be considered when single particle configurations are assigned to high spin states. Average octupole excitation energies of 657(51) keV for {sup 211}At, 1101(28) keV for {sup 212}Rn, 667(25) keV for {sup 213}Fr, and 709(25) keV for {sup 214}Ra are obtained. The calculated level energies are in a good agreement with the experimental level energies within the error limit of 4.3%. (orig.)

Hwang, J.K.; Hamilton, J.H.; Ramayya, A.V. [Vanderbilt University, Physics Department, Nashville, TN (United States)

2013-12-15

390

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 outlined in the last section.

Zahaf, Mohammed Brahim; Manchon, Dominique

2013-01-01

391

Fabrication, microstructure, properties and deformation mechanisms of a nanocrystalline aluminum-iron-chromium-titanium alloy by mechanical alloying  

Science.gov (United States)

A multi-phase nanocrystalline Al93Fe3Cr2Ti 2 alloy containing 30 vol.% intermetallic particles was prepared via mechanical alloying starting from elemental powders, followed by hot extrusion. The grain size of 6-45 nm can be achieved after 30-hours of milling. Thermal stability of nanostructured Al93Fe3Ti2Cr 2 alloys was investigated using a variety of analytical techniques including modulated differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, transmission electron microscopy. The MA-processed Al93Fe 3Ti2Cr2 alloy in the as-milled condition was composed of an Al-based supersaturated solid solution with high internal strains. Release of internal strains, intermetallic precipitation and grain growth occurred upon heating of the MA-processed Al alloy. Nevertheless, grain growth in the MA-processed Al alloy was very limited and fcc-Al grains with sizes in the range of 20 nm were still present in the alloys after exposure to 450°C (0.77 Tm). Systematic compressive tests and modulus measurements were performed as a function of temperature and strain rate to investigate the deformation behavior and mechanisms of the nc Al-Fe-Cr-Ti alloys. High strengths and moduli at both ambient and elevated temperatures have been demonstrated. The ductility of the nc Al93Fe3Cr2Ti2 alloy depends strongly on whether the oxide film at the prior powder particle boundary has been broken down or not. The MA-processed Al93Fe3Cr 2Ti2 alloy is brittle when the oxide film is continuous at PPB, and is ductile when the oxide film is broken down into discontinuous particles during extrusion. It is argued that the compressive strength at ambient temperature is controlled by propagation of dislocations into nc fcc-Al grains, whereas the compressive strength at elevated temperature is determined by dislocation propagation as well as dynamic recovery. Since the stress for dislocation propagation into nc fcc-Al grains increases with decreasing the grain size, the smaller the grain size, the higher the compressive strength. This new microstructural design approach could present opportunities for exploiting nc materials in structural applications at both ambient and elevated temperatures. The nanocrystalline Al-Fe-Cr-Ti alloy exhibited significant difference in deformation behavior between tension and compression at 25, 200 and 300°C. However, the strengths obtained in tension and compression were similar at 400°C. Systematic microstructure examinations and deformation mechanism analyses indicate that the asymmetry of this nc Al93Fe3Cr 2Ti2 alloy is related to its dislocation mediated plastic deformation mechanism, its nanoscale grain microstructure, and premature brittle failure in tension tests.

Luo, Hong

392

Study of large-scale mechanical properties and deformation by modeling of the La Clapière landslide by a numerical modeling approach (Saint-Etienne de Tinée, France).  

Science.gov (United States)

"La Clapière" Landslide is a large unstable slope located in the South-eastern part of France, in the Alps, about 80 km North of Nice city. Like many other deep-seated slope deformations, an interdisciplinary approach based on observations and measurements has been done on this landslide since 1970. A monitoring of the site is working since 1982 (Follaci, 1987, 1988 1999; Guglielmi et al., 2001, 2002; Merrien-Soukatchoff et al., 2001). Several conceptual scenarii of the rupture initiation and the evolution of the slope have been proposed (Follaci, 1987,1999). However, these different observational analysis have not the potential to describe the processes involved on the generation and development of a creeping rock mass out of an originally compact rock . A promising approach to reach this goal is the geomechanical modelling of the structures and properties of the creeping or sliding mass. To our knowledge, only two modelling study have been done on "La Clapière" landslide (Merrien-Soukatchoff et al., 2001; Gunzburger et al., 2002). These authors have tested, with the code UDEC, the mechanism of gravitational toppling and the influence of the deglaciation on the initiation of the instability. The purpose of this abstract is to relate the work we are undertaking on the Clapière landslide through two-dimensional finite element modelling (ADELI) (Hassani, 1994; Hassani et al., 1997). A Drucker-Prager elastoplastic behaviour is used in the model that is subject only to the gravity. We tested different geomechanical parameters (Cohesion, angle of internal friction) in order to (1) determine the critical value of these parameters from which the destabilisation is possible, (2) localise zones of plastic deformation and its temporal and spatial evolutions. We obtain a critical value of cohesion and angle of internal friction respectively in the range ]2.02 MPa; 1,99 MPa] and ]27,84^o ;27,55^o]. These values are compatible with the geomechanical parameters proposed by Gunzburger (2001) from measurements directly done on the site. We observe also a good agreement between the calculated deformation and the actual morphology of the site. Furthermore, the temporal evolution of the deformation show a maximum localised at a depth between 80 and 130 m which is also in good agreement with geophysical data obtained by electrical method which suggest the presence of sliding surface at this depth.

Tric, E.; Bouissou, S.; Lebourg, T.; Jomard, H.; Guglielmi, Y.

2003-04-01

393

Evaluation of Fault Zone Structure and Properties at Depth, with Insights into Deformation and Alteration of the San Andreas Fault at SAFOD  

Science.gov (United States)

We examine the physical properties and structure of the San Andreas fault with the SAFOD wireline geophysical data combined with data from cuttings and core. We examined geophysical logs from the SAFOD borehole starting at an approximate measured depth of 3 km to the end of the drill hole at 4 km; this area includes the region interpreted to be the main and active part of the San Andreas Fault, which lies in a sequence of deformed sandstone, siltstone, shale, and Franciscan rocks. Franciscan lithologies include fine-grained siltstones and block-in-matrix melange. Geophysical logs show the presence of a low velocity zone from 3150 to 3410 m measured depth. Active slip surfaces within the low velocity zone correspond to sharp decreases in velocity and density and increasing porosity. Conventional comparisons of the amount of fracturing, alteration, and cataclasite in the LVZ with wireline data reveal complex relationships. The are few to weak correlations between the velocity data and the measures of the amount of deformation, and in places the velocity increases with deformation features in the low-velocity zone. The LVZ may correlate with low-velocity rock types within the fault zone. We also use inversion methods to examine the data, and found three distinct clusters of data in which velocity, density, and resistivities correlate. This relationship could be due to the presence serpentinite or a decrease in porosity and increase in density due to compaction and/or cementation of the sandstones and siltstones. Estimates of the elastic moduli from the wireline data for the SAF at depth and the Buzzard Canyon fault southwest of the SAF show that both faults exhibit low modulli. The lowest velocity/moduli rocks are sheared mélange/fault gouge diamictites and serpentinites within the narrow zones of the active part of the San Andreas fault, and also within the Buzzard Canyon fault, where Salinain grantic rocks are juxtaposed on Salinian-derived arkosic rocks. These results indicate that interactions of active deformation and mineralogic transformation may create narrow, very weak slip zones at depth; in one case the protolith is relateively weak, whereas in the Buzzard Canyon fault low-velocity rocks were either generated within the fault zone or comprise a fault sliver entrained within the zone.

Evans, J. P.; Jeppson, T. N.; Keighley Bradbury, K.; Lowry, A. R.

2009-12-01

394

Analysis on q-deformed quantum spaces  

CERN Document Server

A q-deformed version of classical analysis is given to quantum spaces of physical importance, i.e. Manin plane, q-deformed Euclidean space in three or four dimensions, and q-deformed Minkowski space. The subject is presented in a rather complete and selfcontained way. All relevant notions are introduced and explained in detail. The different possibilities to realize the objects of q-deformed analysis are discussed and their elementary properties are studied. In this manner attention is focused on star products, q-deformed tensor products, q-deformed translations, q-deformed partial derivatives, dual pairings, q-deformed exponentials, and q-deformed integration. The main concern of this work is to show that these objects fit together in a consistent framework, which is suitable to formulate physical theories on quantum spaces.

Wachter, H

2006-01-01

395

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

International Nuclear Information System (INIS)

Fe–Pd-based ferromagnetic shape memory alloys constitute an exciting class of magnetically switchable smart materials that reveal excellent mechanical properties and biocompatibility. However, their application is severely hampered by a lack of understanding of the physics at the atomic scale. A many-body potential is presented that matched ab inito calculations and can account for the energetics of martensite ? austenite transition along the Bain path and relative phase stabilities in the ordered and disordered phases of Fe–Pd. Employed in massively parallel classical molecular dynamics simulations, the impact of order/disorder, point defects and severe plastic deformation in the presence of single- and polycrystalline microstructures are explored as a function of temperature. The model predictions are in agreement with experiments on phase changes induced by ion irradiation, cold rolling and hammering, which are also presented. (paper)

2012-10-01

396

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

397

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

398

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.

2009-08-01

399

Properties of the rotational bands in 161Er  

International Nuclear Information System (INIS)

High-spin states in 161Er have been studied experimentally using the 150Nd(16O,5n) reaction at a beam energy of 86 MeV. The 5/2+[642], 3/2-[521], and 11/2-[505] bands are extended up to high-spin states, and particularly the ?=-1/2 branch of the ground state 3/2-[521] band is revised significantly. The relatively enhanced E1 transitions from the 3/2-[521] band to the 5/2+[642] band are observed. The band properties are analyzed within the framework of a triaxial particle-rotor model, and near-prolate shape and triaxial deformation are proposed to the 3/2-[521] and 5/2+[642] bands, respectively. Signature inversion occurs in the 3/2-[521] band after the band crossing in 161Er, and the systematics of the signature inversion associated with the 3/2-[521] configuration are discussed. By analyzing the properties of the relatively enhanced E1 transitions, it is found that the R(E1/E2) values show angular momentum dependence before the band crossing, and these enhanced E1 transitions could be attributed to octupole softness.

2011-03-01

400

Crustal Deformation  

Science.gov (United States)

This site contains 24 questions on the topic of crustal deformation, which covers folding and faulting, rock behavior, geologic structures, and types of stress. This is part of the Principles of Earth Science course at the University of South Dakota. Users submit their answers and are provided immediate feedback.

Heaton, Timothy

 
 
 
 
401

Cross field diffusion and fluctuation spectra in a levitated octupole in the presence of a toroidal field  

Energy Technology Data Exchange (ETDEWEB)

The diffusion coefficient, D/sub perpendicular to/, for a collisionless hydrogen plasma was measured in the Levitated Octupole when a weak toroidal field was added. A 20-fold decrease in the anomalous diffusion was observed with B/sub T//B/sub P/ approx. 0.1. Since the plasma is collisionless locally trapped particles in the poloidal field mirrors allows the convective cell activity (f < 600 Hz) to persist even when toroidal field was added. A shift in the k/sub perpendicular to/ spectrum to shorter wavelengths was noted. Measurements and calculations indicate that the higher frequency portion of the spectrum (f > 600 Hz) cannot be responsible for the observed diffusion.

Ehrhardt, A. B.; Garner, H. R.; Navratil, G. A.; Post, R. S.

1980-11-01

402

Correlation of substructure with mechanical properties of plastically deformed reactor structural materials. Progress report, January 1, 1976--June 30, 1977  

Energy Technology Data Exchange (ETDEWEB)

Transmission electron microscopy used to evaluate the deformation (creep, fatigue and tensile) induced microstructure of 304 SS, Incoloy 800, 330 SS and three of the experimental alloys (E19, E23 and E36) obtained from the National Alloy Program clearly shows that the relationship between the subgrain size (lambda) and the applied stress (sigma) obeys the equation lambda = Ab (sigma/E)/sup -1/ where A is a constant of the order of 4, b the Burgers rector and E is Young's modulus. Hot-hardness studies on 304 SS, 316 SS, Incoloy 800, 2 /sup 1///sub 4/ Cr-1 Mo steels, 330 SS, Inconel 718, PE-16, Inconel 706, M-813 and the above three experimental alloys suggests that reasonable effective activation energies for creep may be obtained through the use of the hardness test as a strength microprobe tool. The ordering of the strength levels obtained through hot-hardness follows quite closely that obtained in tensile tests when those data are available.

Moteff, J.

1977-07-08

403

Effect of hydrogen on deformation structure and properties of CMSX-2 nickel-base single-crystal superalloy  

Science.gov (United States)

Material used in this study was a heat of the alloy CMSX-2. This nickel-based superalloy was provided in the form of oriented single crystals, solutionized for 3 hrs at 1315 C. It was then usually heat treated as follows: 1050 C/16h/air cool + 850 C/48h/air cool. The resulting microstructure is dominated by cuboidal, ordered gamma precipitates with a volume fraction of about 75% and an average size of 0.5 microns. In brief, the most compelling hydrogen induced-changes in deformation structure are: (1) enhanced dislocation accumulation in the gamma matrix; and (2) more extensive cross-slip of superdislocations in the gamma precipitates. The enhanced dislocation density in gamma acts to decrease the mean free path of a superdislocation, while easier cross slip hinders superdislocation movement by providing pinning points in the form of sessile jobs. Both processes contribute to the increase of flow stress and the notable work hardening that occurs prior to fracture.

Dollar, M.; Bernstein, I. M.; Walston, S.; Prinz, F.; Domnanovich, A.

1987-01-01

404

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

2011-01-01

405

Spinal deformity.  

Science.gov (United States)

Early results of scoliosis screening programs have demonstrated that mild spinal deformity is common, usually nonprogressive, and often requires no specific treatment. The role of the primary care physician is an important one in identifying the rare case, which is secondary to some underlying disorder which itself requires treatment, and the progressive curves, which should be managed by bracing. The informed physician can make this separation efficiently with minimum cost to the family and minimum radiation exposure to the patient. PMID:7373257

Staheli, L T

1980-06-01

406

Deformation-Induced Anisotropy of Polymers  

Science.gov (United States)

New theory calculates anisotropies induced by large deformations in polymers. Theory was developed primarily for calculating anistropy of thermal expansivity, but is also applicable to thermal conductivity, elastic moduli and other properties. Theory assumes that in isotropic state, long polymer chains are randomly coiled and not oriented in particular direction. They acquire an orientation when material is deformed. As average molecular orientation increases with deformation, properties of bulk material exhibit averaging of the microscopic anistropies of the oriented molecular segments.

Peng, S. T. J.; Landel, R. F.

1982-01-01

407

Three-parameter (two-sided) deformation of Heisenberg algebra  

CERN Document Server

A 3-parametric two-sided deformation of Heisenberg algebra (HA), with p,q-deformed commutator in the l.h.s. of basic defining relation and certain deformation of its r.h.s., is introduced and studied. The third deformation parameter \\mu appears in an extra term in the r.h.s. as pre-factor of Hamiltonian. For this deformation of HA we find novel properties. Namely, we prove it is possible to realize this (p,q,\\mu)-deformed HA by means of some deformed oscillator algebra. Also, we find the unusual property that the deforming factor \\mu\\ in the considered deformed HA inevitably depends explicitly on particle number operator N. Such a novel N-dependence is special for the two-sided deformation of HA treated with its deformed oscillator realizations.

Gavrilik, A M

2012-01-01

408

Electronic properties and drift of nonequilibrium charge carriers in Si and GaAs semiconductor structures under alternating-strain-induced deformation  

International Nuclear Information System (INIS)

Full text: It is well known that the drift of nonequilibrium charge carriers in the semiconductors is one of the basic processes determining the efficiency of solar cells, nuclear radiation detectors and other semiconductor devices. Therefore at present article the processes of drift of nonequilibrium charge carriers in nonepiezosemiconductors (Si) and piezosemiconductors (GaAs) structures were studied. As alternating-strain-induced deformation used the longitudinal ultrasonic waves with variable amplitude and a frequency ranging within f = 10; 50 MHz were generated by a quartz transducer acoustically coupled to a cathode contact of the photodetector. The electric voltage to the quartz transducer was supplied from an HF generator. It is shown that the alternating-strain-induced deformation fields significantly influence the transport of charge carriers and photoelectrical properties of Si and GaAs semiconductor structures with traps and heterogeneity. The amplitude characteristics of the semiconductors were measured on a special setup for the amplitude analysis, which allowed the collected charge to be estimated with high accuracy. After the electron hole pair generation, the sample featured the motion of nonequilibrium charge carriers.It is shown that during the drift of electrons through the crystal, the current slightly changing as a result of trapping of a part of the nonequilibrium carriers by traps. If the sample was subjected to the action of ultrasonic waves, dependence of the signal amplitude on the field strength was described complex form which the physical reasons of this behavior were considered in the present article. Besides for comparison it was study of the photoelectrical, reflection and spectral characteristics of nonepiezosemiconductor and piezosemiconductors. (authors)

2007-09-01

409

Tailoring the mechanical properties of nanocrystalline fcc metals: A molecular dynamics study on the effects of twins and miscible solutes on deformation processes  

Energy Technology Data Exchange (ETDEWEB)

For the presence of twins, a strengthening effect of nanocrystalline metals has been reported in experiment and simulation. For the case of miscible solutes, little is known about their effect on the structure and properties of nanocrystalline metals. We present a comparative atomistic study on the effect of twins on the deformation behavior of nanocrystalline Cu and Pd. A new analysis method based on an automated Burgers circuit is applied, which allows us to analyze the dislocation interactions with twin planes and grain boundaries, and to directly measure dislocation, stacking fault, and twin boundary densities as functions of strain. We show, how a strengthening or softening effect of twins depends on the properties of a given fcc material i.e. its generalized planar fault energies. For the case of Pd, we additionally show, how miscible solutes (Au) influence the behavior of our nanocrystalline structures in the elastic and plastic regime and why this depends on the distribution of the solutes. Here, samples are alloyed using a hybrid MD-MC method sampling the semi-grandcanonical ensemble. The automated Burgers search is applied as well and allows us to quantitatively compare the slip processes and planar faults as a function of composition and relaxation state.

Schaefer, Jonathan; Stukowski, Alexander; Albe, Karsten [TU Darmstadt, Darmstadt (Germany)

2011-07-01

410

High-temperature deformation behavior and mechanical properties of rapidly solidified Al-Li-Co and Al-Li-Zr alloys  

International Nuclear Information System (INIS)

The deformation behavior at 25-300 C of rapidly solidified Al-3Li-0.6Co and Al-3Li-0.3Zr alloys was studied by tensile property measurements and transmission electron microscopic examination of dislocation substructures. In binary Al-3Li and Al-3Li-Co alloys, the modulus normalized yield stress increases with an increase in temperature up to 150 C and then decreases. The yield stress at 25 C of Al-3Li-0.3Zr alloys is 180-200 MPa higher than that of Al-3Li alloys. However, the yield stress of the Zr-containing alloy decreases drastically with increasing temperatures above 75 C. The short-term yield stresses at 100-200 C of the Al-3Li-based alloys are higher than that of the conventional high-temperature Al alloys. The temperature dependences of the flow stresses of the alloys were analyzed in terms of the magnitudes and temperature dependences of the various strengthening contributions in the two alloys. The dislocation substructures at 25-300 C were correlated with mechanical properties. 19 references

1984-01-01

411

On the relationship between gluten protein composition of wheat flours and large-deformation properties of their doughs  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Six European and two Canadian wheat cultivars selected according to their different performance in baked cereal products. The gluten protein composition of the respective flours was studied and related to the rheological and fracture properties of optimally mixed flour doughs tested in uniaxial extension. Water addition required for optimum dough development was positively correlated with gluten protein content, indicating that all glutens required similar amounts of water for proper hydratio...

Sliwinski, E. L.; Kolster, P.; Prins, A.; Vliet, T.

2004-01-01

412

Nanostructure and related mechanical properties of an Al-Mg-Si alloy processed by severe plastic deformation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Microstructural features and mechanical properties of an Al-Mg-Si alloy processed by high-pressure torsion have been investigated using transmission electron microscopy, X-ray diffraction, three-dimensional atom probe, tensile tests and microhardness measurements. It is shown that HPT processing of the Al-Mg-Si alloy leads to a much stronger grain size refinement than of pure aluminium (down to 100 nm). Moreover, massive segregation of alloying elements along grain boundarie...

Nurislamova, Gulnaz; Sauvage, Xavier; Murashkin, Maxim; Islamgaliev, Rinat; Valiev, Ruslan

2008-01-01

413

MEMS Actuated Deformable Mirror  

Energy Technology Data Exchange (ETDEWEB)

This ongoing work concerns the creation of a deformable mirror by the integration of MEMS actuators with Nanolaminate foils through metal compression boning. These mirrors will use the advantages of these disparate technologies to achieve dense actuation of a high-quality, continuous mirror surface. They will enable advanced adaptive optics systems in large terrestrial telescopes. While MEMS actuators provide very dense actuation with high precision they can not provide large forces typically necessary to deform conventional mirror surfaces. Nanolaminate foils can be fabricated with very high surface quality while their extraordinary mechanical properties enable very thin, flexible foils to survive the rigors of fabrication. Precise metal compression bonding allows the attachment of the fragile MEMS actuators to the thin nanolaminate foils without creating distortions at the bond sites. This paper will describe work in four major areas: (1) modeling and design, (2) bonding development, (3) nanolaminate foil development, (4) producing a prototype. A first-principles analytical model was created and used to determine the design parameters. A method of bonding was determined that is both strong, and minimizes the localized deformation or print through. Work has also been done to produce nanolaminate foils that are sufficiently thin, flexible and flat to be deformed by the MEMS actuators. Finally a prototype was produced by bonding thin, flexible nanolaminate foils to commercially available MEMS actuators.

Papavasiliou, A; Olivier, S; Barbee, T; Walton, C; Cohn, M

2005-11-10

414

Neurite branching on deformable substrates  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The mechanical properties of substrates underlying cells can have profound effects on cell structure and function. To examine the effect of substrate deformability on neuronal cell growth, protein-laminated polyacrylamide gels were prepared with differing amounts of bisacrylamide to generate substrates of varying deformability with elastic moduli ranging from 500 to 5500 dyne/cm2. Mouse spinal cord primary neuronal cells were plated on the gels and allowed to grow and extend neurites for seve...

Flanagan, Lisa A.; Ju, Yo-el; Marg, Beatrice; Osterfield, Miriam; Janmey, Paul A.

2002-01-01

415

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)

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

416

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 Multimedia

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

417

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

418

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

419

Relations between texture, superplastic deformation and mechanical properties of thin TA6V slabs. [Ti-Al-V  

Energy Technology Data Exchange (ETDEWEB)

Superplastic tensile tests have been carried out up to elongations of 20 and 100 % at 925 C on a thin TA6V slab. To study the influence of texture, test pieces axes have been oriented with four angles from the rolling direction. No pronounced effect of texture on superplastic behaviour is clearly enhanced by the usual stress/strain rate law. The type of microstructural changes and the variations of the texture intensity may be correlated with the strain range. As for the starting material, tensile properties of the stretched material at room temperature are strongly dependent on texture. (orig.)

Benay, O. (SNECMA, Dept. des Materiaux et Procedes, YKOM 4, 91 Evry (France)); Lucas, A.S. (SNECMA, Dept. des Materiaux et Procedes, YKOM 4, 91 Evry (France)); Obadia, S. (SNECMA, Dept. des Materiaux et Procedes, YKOM 4, 91 Evry (France)); Vadon, A. (ISGMP, Ile du Saulcy, 57 Metz (France))

1994-01-01

420

Fragmentation of giant multipole resonances in deformed nuclei  

International Nuclear Information System (INIS)

The fragmentation of the giant monopole resonance in deformed nuclei is first studied by coupling the monopole oscillation with the quadrupole oscillation by means of the variational procedure for resonance frequencies. It is shown that, for non-axial symmetry, the monopole oscillation couples with both m = 0 and 2 modes of the quadrupole oscillation and the giant monopole resonance is split into three components, whereas for axial symmetry, the fragmentation is given by E0(1+0.86delta2-+1.25delta3) and E0(0.74-+0.22delta-0.21delta2+-0.57delta3), where E0 is the giant monopole resonance energy for spherical nuclei, delta is the deformation parameter, and the upper and lower signs stand for prolate and oblate deformations, respectively. The initial fragmentation of the giant quadrupole resonance is seen to be little modified by the coupling, except for the 7 = 0 mode which is split into two components. The variational method is extended to general multipoles for an ellipsoid and the fragmentation of giant multipole resonances in deformed nuclei is investigated for both axial and non-axial symmetries. A brief discussion is also made about the meaning of the energy eigenvalue involved in the model wave equation in terms of multipole sum rules. The giant dipole resonance for the static octupole deformation is shortly considered. The giant E0 and E3 resonances for largely deformed nuclei are finally examined by solving the spheroidal eigenvalue equation and they are compared with the results of the giant dipole and quadrupole resonances. (orig.)

1983-06-06

 
 
 
 
421