WorldWideScience

Sample records for octupole deformation properties

  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)

  2. Rotations of Nuclei with Octupole Deformations

    International Nuclear Information System (INIS)

    We study collective interactions capable to generate rotations in nuclei with a simultaneous presence of octupole and quadrupole deformations. On this basis we propose a collective Hamiltonian which incorporates the standard quadrupole terms, octupole terms classified according to the irreducible representations of the octahedron point symmetry group, a quadrupole-octupole interaction, as well as a term for the band-head energy linear in K (the projection of angular momentum on the body-fixed z-axis). The energy is subsequently minimised with respect to K for each given value of the angular momentum I, resulting in K values increasing with I within each band. We demonstrate that this Hamiltonian is able to reproduce a variety of 'beat' patterns observed recently for the odd-even staggering in octupole bands of light actinides. In addition, we suppose that the model can be applied to reproduce the staggering effects in rotational negative parity bands built on octupole vibrations. On the above basis we expect that the interactions involved would provide a relevant handle in the study of collective phenomena in nuclei and other quantum mechanical systems with a presence of octupole degrees of freedom. (authors)

  3. Octupole Deformed Nuclei in the Actinide Region

    CERN Multimedia

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

    2002-01-01

    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.

  4. Nuclear dynamical octupole deformation in heavy-ion reactions

    Science.gov (United States)

    Tang, Cheng; Jin, Xin; Wang, Nan; Zhao, En-Guang

    2015-10-01

    Within the quantum molecular dynamics (QMD) model, the dynamical octupole deformation is studied as a function of the central distance between the projectile and target in the approaching process of heavy-ion fusion reactions. The dependence of the maximum dynamical octupole deformations on the incident energies is also investigated. The dynamical octupole deformations can be observed during the approaching process, and the maximum dynamical octupole deformations become more significant with decreasing incident energies. The distributions of the proton and neutron centers in the projectile and target are also investigated, respectively. In the approaching process of heavy-ion fusion reactions, the separation between proton centers for two nuclei is larger than that between neutron centers because of the strong Coulomb potential.

  5. Search for octupole deformation in neutron-rich Xe isotopes

    International Nuclear Information System (INIS)

    A search for octupole deformation in neutron-rich Xe isotopes has been conducted by prompt gamma-ray spectroscopy of secondary fragments produced in the spontaneous fission of 248Cm. The spectrometer consisted of the Eurogam 1 array and a set of 5 LEPS detectors. Level schemes were constructed for Xe isotopes with mass number ranging from 140 to 144 and excited states for 143,144Xe nuclei were observed for the first time. None of the level schemes exhibit an alternating parity quasimolecular band, a feature usually expected in nuclei in which octupole correlation effects are strong enough to produce stable octupole deformation. For several isotopes, structures observed in the level schemes are consistent with an octupole softness of the nuclei. (orig.)

  6. Deformed Hartree-Fock model of parity mixing and octupole moments in neutron rich barium nuclei

    International Nuclear Information System (INIS)

    A deformed Hartree-Fock calculation with parity mixing reveals considerable octupole deformation for neutron rich barium nuclei. The energy surfaces for 142-148Ba as a function of octupole deformation are calculated and show a single humped shape with the minimum for positive octupole deformation slightly lower in energy. Parity mixing and octupole deformation show a typical shell effect and are negligible for 146Ce and 148Ce. (author)

  7. Search for octupole deformation in neutron rich Xe isotopes

    International Nuclear Information System (INIS)

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

  8. Search for octupole deformation in neutron rich Xe isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Bentaleb, M.; Schulz, N.; Lubkiewicz, E. [Universite Louis Pasteur, Strasbourg (France). Centre de Recherches Nucleaires] [and others

    1994-07-01

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

  9. Possible ground-state octupole deformation in 229Pa

    International Nuclear Information System (INIS)

    Evidence is presented for the occurrence of a (5/2)+- parity doublet as the ground state of 229Pa, in agreement with a previous theoretical prediction. The doublet splitting energy is measured to be 0.22 +- 0.05 keV. The relation of this doublet to ground-state octupole deformation is discussed. .ID LV2109 .PG 1762 1764

  10. Studies of Stable Octupole Deformations in the Radium Region

    CERN Multimedia

    2002-01-01

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

  11. Further confirmation of octupole deformation in ^144Ba

    Science.gov (United States)

    Yzaguirre, W. A.; Hamilton, J. H.; Liu, S. H.; Ramayya, A. V.; Hwang, J. K.; Luo, Y. X.; Rasmussen, J. O.; Zhu, S. J.

    2009-11-01

    The energy levels in ^144Ba have been studied with our high statistics 5.7 x10^11 triple- and higher- fold coincidence data taken with Gammasphere. There are reinforcing shell gaps for ?2= 0.13 for Z=56 and Z=88, so octupole deformation is expected in ^144Ba. The even parity ground state band is seen to high spin with crossing E1 transitions from an odd spin, negative parity band earlier, the expected si=1 band. Limited evidence for the expected si=-1 band with the same spins and opposite parities has been reported. si=-1 band has been clearly established now with the expected crossing transitions between the even and odd spins members. In addition, numbers of new crossing transitions in the si=1 band and between the si=-1 band and +1 are seen. These data firmly established the octupole deformation of ^144Ba. Work supported by the U.S. Department of Energy under Grants and Contract Nos. DE-FG05-88ER40407 and DE-AC03- 76SF00098.

  12. Nuclear fusion as a probe for octupole deformation in 224Ra

    Science.gov (United States)

    Kumar, Raj; Lay, J. A.; Vitturi, A.

    2015-11-01

    Background: Nuclear fusion has been shown to be a useful probe to study the different nuclear shapes. However, the possibility of testing octupole deformation of a nucleus with this tool has not been fully explored yet. The presence of a static octupole deformation in nuclei will enhance a possible permanent electric dipole moment, leading to a possible demonstration of parity violation. Purpose: To check whether static octupole deformation and octupole vibration in fusion give different results so that both situations could be experimentally disentangled. Method: Fusion cross sections are computed in the coupled-channel formalism making use of the ingoing-wave boundary conditions (IWBC) for the systems 16O+144Ba and 16O+224Ra . Results: Barrier distributions of the two considered schemes show slightly different patterns. In the case of 144Ba, the difference between them is negligible. For the 224Ra case, perceptible differences are found in correspondence with its larger octupole deformation. However, the possibility of disentangling both schemes is not guaranteed and it will depend on the available experimental accuracy and the strength of the octupole deformation. Conclusions: The measurement of barrier distributions could be a complementary probe to support the presence of octupole deformation.

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

    International Nuclear Information System (INIS)

    The potential energy surfaces of even-even 142-156Ba are investigated in the constrained reflection-asymmetric relativistic mean-field approach with parameter set PK1. It is shown that for the ground states, 142Ba is near spherical, 156Ba well quadrupole-deformed, and in between 144-154Ba octupole deformed. In particular, the nuclei 148,150Ba 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 148Ba with ?2 ? 0.26 and ?3 ? 0.17 are found. Furthermore, the performance of the octupole deformation driving pairs (?2f7/2, ?1i13/2) and (?2d5/2, ?1h11/2) is demonstrated by analyzing the single-particle levels near Fermi surfaces in 148Ba. (authors)

  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. 21 references

  15. Definition of the actinide region of static quadrupole-octupole deformation

    International Nuclear Information System (INIS)

    Ground state spins of odd-A nuclei in the region just beyond 208Pb are compiled. They are compared with the theoretically predicted spins of an axially symmetric, reflection asymmetric nucleus with octupole deformaiton ?3 = 0.08 to determine the region of static quadrupole-octupole deformation. Coexistence of different shapes and the corresponding spectra in the same nucleus are predicted in the transition regions. (orig.)

  16. Stabilization of octupole deformation with angular-momentum increase in the alternating-parity bands

    Science.gov (United States)

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

    2015-10-01

    Background: Low-lying octupole collective excitations play an important role in describing the structure of nuclei in different regions of the nuclide chart. Ground state alternating-parity rotational bands combining both positive- and negative-parity states are known in several nuclei. The experimental data indicate that octupole deformation becomes stable with increase of the angular momentum. Purpose: We introduce a nondimensional characteristic of the spectra of the ground state alternating-parity bands and apply it to investigation of a stabilization of the octupole deformation with increase of the angular momentum. Method: We analyze the experimental data on the energies of the states belonging to the alternating-parity bands based on the ratio of the interpolated and the experimental energies of the negative-parity states. Interpolated energies are determined by the experimental energies of the neighboring positive-parity states assuming smooth dependence on the angular momentum. Results: The values of the ratio of the interpolated and the experimental energies of the negative-parity states belonging to the ground state alternating-parity bands of 144 ,146Ba and some rare-earth and actinide nuclei are evaluated. Conclusion: It is shown that the angular-momentum dependence of the ratio of the interpolated and the experimental energies of the negative-parity states belonging to the ground state alternating-parity bands of 144 ,146Ba and some rare-earth and actinide nuclei indicates stabilization of the octupole deformation with angular-momentum increase.

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

    CERN Document Server

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

    2012-01-01

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

  18. Direct Evidence of Octupole Deformation in Neutron-Rich $^{144}$Ba

    CERN Document Server

    Bucher, B; Wu, C Y; Janssens, R V F; Cline, D; Hayes, A B; Albers, M; Ayangeakaa, A D; Butler, P A; Campbell, C M; Carpenter, M P; Chiara, C J; Clark, J A; Crawford, H L; Cromaz, M; David, H M; Dickerson, C; Gregor, E T; Harker, J; Hoffman, C R; Kay, B P; Kondev, F G; Korichi, A; Lauritsen, T; Macchiavelli, A O; Pardo, R C; Richard, A; Riley, M A; Savard, G; Scheck, M; Seweryniak, D; Smith, M K; Vondrasek, R; Wiens, A

    2016-01-01

    The neutron-rich nucleus $^{144}$Ba ($t_{1/2}$=11.5 s) is expected to exhibit some of the strongest octupole correlations among nuclei with mass numbers $A$ less than 200. Until now, indirect evidence for such strong correlations has been inferred from observations such as enhanced $E1$ transitions and interleaving positive- and negative-parity levels in the ground-state band. In this experiment, the octupole strength was measured directly by sub-barrier, multi-step Coulomb excitation of a post-accelerated 650-MeV $^{144}$Ba beam on a 1.0-mg/cm$^2$ $^{208}$Pb target. The measured value of the matrix element, $\\langle 3_1^- \\| \\mathcal{M}(E3) \\| 0_1^+ \\rangle=0.65(^{+17}_{-23})$ $e$b$^{3/2}$, corresponds to a reduced $B(E3)$ transition probability of 48($^{+25}_{-34}$) W.u. This result represents an unambiguous determination of the octupole collectivity, is larger than any available theoretical prediction, and is consistent with octupole deformation.

  19. Accuracy of the multipole expansion of density distribution in the presence of octupole deformation

    International Nuclear Information System (INIS)

    The accuracy of multipole expansion of density distribution for deformed nuclei is tested. The interaction potential for a deformed-spherical pair of nuclei was calculated using the folding model derived from zero-range nucleon–nucleon (NN) interaction. We considered two spherical projectiles Ca40 and Pb208 scattered on U238 deformed target nucleus. The error in the heavy ion (HI) potential resulting from using a truncated multipole density expansion is evaluated for each case in the presence of octupole deformation ?3 besides quadrupole ?2. We are interested in the value of error for R ? RT (touching distance). We found that for values of |?3|?0.1 the error at R = RT reaches reasonable values when six terms expansion is used. For |?3| = 0.2, we calculated the Coulomb barrier parameters using realistic NN force and found that the large error present in six terms for zero range force decreases strongly to less than 1% when the zero range is added to finite range forces and Coulomb interaction to form the Coulomb barrier. It is noted that the negative value of octupole deformation parameters ?3 = -0.1 produce error at orientation angle ? equal in value to that produced at angle (180°-?) for the positive values ?3 = 0.1. We also found that the error decreases as the mass number of the projectile nucleus increases. (author)

  20. Systematic behavior of octupole states in deformed rare earth nuclei and the interacting boson approximation

    International Nuclear Information System (INIS)

    A method for setting ?f, one of the parameters in the interacting boson approximation-1 (IBA-1) with one f boson, by using the systematic behavior of the centroids of observed E3 strength is proposed and applied to obtaining fits for octupole bands in the deformed rare earth region. The ordering of bands with different K values, B(E3) strengths and B(E1) values are well reproduced. The calculations are in good agreement with the data in nearly all the K=0, 1, and 2 octupole bands examined here. The least satisfactory fits were obtained for the K?=0- bands in 160,162Dy. It is predicted that in 160,162,164Dy, 168Er, and 172Yb the K=3 octupole states based on the ground state and having significant E3 strength are above 6 MeV and are strongly fragmented. These results are quite different from predictions made previously. copyright 1996 The American Physical Society

  1. Octupole deformation in the ground states of even-even nuclei: a global analysis within the covariant density functional theory

    CERN Document Server

    Agbemava, S E; Ring, P

    2016-01-01

    A systematic investigation of octupole deformed nuclei is presented for even-even systems with $Z\\leq 106$ located between the two-proton and two-neutron drip lines. For this study we use five most up-to-date covariant energy density functionals of different types, with a non-linear meson coupling, with density dependent meson couplings, and with density-dependent zero-range interactions. Pairing correlations are treated within relativistic Hartree-Bogoliubov (RHB) theory based on an effective separable particle-particle interaction of finite range. This allows us to assess theoretical uncertainties within the present covariant models for the prediction of physical observables relevant for octupole deformed nuclei. In addition, a detailed comparison with the predictions of non-relativistic models is performed. A new region of octupole deformation, centered around $Z\\sim 98, N\\sim 196$ is predicted for the first time. In terms of its size in the $(Z,N)$ plane and the impact of octupole deformation on binding e...

  2. Can strong electric dipole transitions in deformed rare earth nuclei be explained by the macroscopic behavior of the octupole phonon?

    International Nuclear Information System (INIS)

    Strong E1 transitions of greater than 10-3 Weisskopf units occur in many octupole states in the deformed rare earth region. It is shown using the droplet model that the electric dipole moment resulting from the macroscopic behaviour of the octupole phonon cannot by itself account for the observed E1 strengths, and it is observed that this result is consistent with the proposal of Donner and Greiner and of Zilges von Brentano and Richter that admixtures of the giant dipole resonance into the low energy octupole states are responsible for the fast E1 transitions. It is also suggested that calculations similar to those performed by Egido and Robledo for N ? 92 nuclei may be able to reproduce E1 transitions in N = 94-104 nuclei. (orig.)

  3. 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.

  4. Enhanced E1 transition rates and octupole deformation in 225Ac

    International Nuclear Information System (INIS)

    The levels of 225Ac are reliably assigned by detailed measurements of the radiations associated with the ? decay of 229Pa and the ? decay of 225Ra. Extremely large enhancements of E1 transition rates are found in 225Ac. The adequacy of a single-particle description of strong octupole correlations is examined

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

    CERN Document Server

    Greenlees, P T

    1999-01-01

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

  6. Observation of K=1/2 octupole deformed bands in 227Th

    International Nuclear Information System (INIS)

    High-spin states in 227Th have been populated using the reaction 226Ra(?,3n)227Th 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 231U ? 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?=1/2+ and K?=1/2- 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?=1/2+)=-a(K?=1/2-) rigid octupole rotor expectation. A further rotational band is interpreted as having K?=3/2-. Measured D0/Q0 ratios are consistent with an interpolation of the values given for neighboring even-even nuclei, providing further evidence for the significance of strong octupole correlations in this nucleus

  7. Octupole effects in the lanthanides

    Energy Technology Data Exchange (ETDEWEB)

    Urban, W.; Rzaca-Urban, T.; Phillips, W. R.; Durell, J. L.; Leddy, M. J.; Smith, A. G.; Varley, B. J.; Schulz, N.; Bentaleb, M.; Lubkiewicz, E.; Ahmad, I.; Morss, L. R.

    1999-10-22

    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 {sup 139}Xe 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.

  8. 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

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

    International Nuclear Information System (INIS)

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

  10. Octupole collectivity in the Sm isotopes

    International Nuclear Information System (INIS)

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

  11. Octupole Vibrations at High Angular Momenta

    OpenAIRE

    Nakatsukasa, takashi

    1995-01-01

    Properties of octupole vibrations in rapidly rotating nuclei are discussed. Microscopic RPA calculations based on the cranked shell model are performed to investigate the interplay between rotation and vibrations. The ability of this model to describe the properties of collective vibrations built on the ground bands in rare-earth and actinide nuclei is demonstrated at high angular momentum. The octupole vibrational states in even-even superdeformed Hg nuclei are also predict...

  12. Octupole instability in the heavy barium region

    International Nuclear Information System (INIS)

    The Woods-Saxon-Bogolyubov cranking calculations confirm previous expectations of octupole deformed mean fields at low and medium spins in Xe-Sm nuclei with neutron numbers around N=86. Recent experimental data support theoretical results. 8 refs., 3 figs. (author)

  13. Nonaxial-octupole effect in superheavy nuclei

    Science.gov (United States)

    Chen, Y.-S.; Sun, Yang; Gao, Zao-Chun

    2008-06-01

    The triaxial-octupole Y32 correlation in atomic nuclei has long been expected to exist but experimental evidence has not been clear. We find, in order to explain the very low-lying 2- bands in the transfermium mass region, that this exotic effect may manifest itself in superheavy elements. Favorable conditions for producing triaxial-octupole correlations are shown to be present in the deformed single-particle spectrum, which is further supported by quantitative Reflection Asymmetric Shell Model calculations. It is predicted that the strong nonaxial-octupole effect may persist up to the element 108. Our result thus represents the first concrete example of spontaneous breaking of both axial and reflection symmetries in the heaviest nuclear systems.

  14. Nonaxial-octupole effect in superheavy nuclei

    CERN Document Server

    Chen, Y -S; Gao, Zao-Chun

    2008-01-01

    The triaxial-octupole Y$_{32}$ correlation in atomic nuclei has long been expected to exist but experimental evidence has not been clear. We find, in order to explain the very low-lying 2$^-$ bands in the transfermium mass region, that this exotic effect may manifest itself in superheavy elements. Favorable conditions for producing triaxial-octupole correlations are shown to be present in the deformed single-particle spectrum, which is further supported by quantitative Reflection Asymmetric Shell Model calculations. It is predicted that the strong nonaxial-octupole effect may persist up to the element 108. Our result thus represents the first concrete example of spontaneous breaking of both axial and reflection symmetries in the heaviest nuclear systems.

  15. Microscopic analysis of quadrupole-octupole shape evolution

    Directory of Open Access Journals (Sweden)

    Nomura Kosuke

    2015-01-01

    Full Text Available We analyze the quadrupole-octupole collective states based on the microscopic energy density functional framework. By mapping the deformation constrained self-consistent axially symmetric mean-field energy surfaces onto the equivalent Hamiltonian of the sdf interacting boson model (IBM, that is, onto the energy expectation value in the boson coherent state, the Hamiltonian parameters are determined. The resulting IBM Hamiltonian is used to calculate excitation spectra and transition rates for the positive- and negative-parity collective states in large sets of nuclei characteristic for octupole deformation and collectivity. Consistently with the empirical trend, the microscopic calculation based on the systematics of ?2 – ?3 energy maps, the resulting low-lying negative-parity bands and transition rates show evidence of a shape transition between stable octupole deformation and octupole vibrations characteristic for ?3-soft potentials.

  16. Evidence for octupole vibration in the superdeformed well of 109Hg

    International Nuclear Information System (INIS)

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

  17. Search for octupole correlations in 147Nd

    Science.gov (United States)

    Ruchowska, E.; Mach, H.; Kowal, M.; Skalski, J.; P?óciennik, W. A.; Fogelberg, B.

    2015-09-01

    Properties of excited states in 147Nd have been studied with the multispectra and ? ? coincidence measurements. Twenty-four new ? lines and three new levels have been introduced into the level scheme of 147Nd. Using the advanced time-delayed ? ? ? (t ) method, we measured lifetimes of eight excited levels in 147Nd, populated via the ? decay of 147Pr. We have determined reduced transition probabilities for 30 ? transitions. Multidimensional potential energy surface calculations performed for 147Nd suggest two single-quasiparticle configurations with nonzero octupole deformation, with K =1 /2 and K =5 /2 . Our calculations also predict a sizable value of the electric dipole moment | D0|=0.26 e fm for this nucleus, while experimentally, a lower limit of | D0|?0.02 e fm has been evaluated for the supposed K =1 /2 parity doublet. In contrast to the theoretical results, we do not observe the parity doublet bands with K =5 /2 . This, and the lack of theoretically expected E 1 strength in Nd,149147 may signal some poorly understood structural effect in the odd-N lanthanides.

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

    International Nuclear Information System (INIS)

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

  19. Improvements on the present theoretical understanding of octupole correlations

    Directory of Open Access Journals (Sweden)

    Robledo L.M.

    2014-03-01

    Full Text Available Some intriguing results, obtained in a recent survey of octupole properties for all even-even nuclei, are reanalyzed in order to understand the origin of the strong disagreement with experimental data and/or the strange behaviours observed. The limitations of the rotational formula to describe E1 and E3 transition strengths are discussed as well as the role played by octupole-quadrupole coupling in some specific nuclei.

  20. Deformation Properties of Unbound Granular Aggregates

    OpenAIRE

    Uthus, Lillian

    2007-01-01

    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...

  1. Octupole vibrational states in the lead region

    International Nuclear Information System (INIS)

    Collective properties of 206Pb, 207Pb, 208Pb and 209Bi have been investigated with gamma-ray spectroscopy using electromagnetic excitation by 208Pb projectiles. By measuring the absolute yields of the de-excitation γ-rays, B(E3) values for the 1-phonon octupole vibrational states were obtained. While the present data for 208Pb and 209Bi are consistent with earlier publications, much smaller values have been found for 206Pb abd 207Pb. Only for the doubly magic nucleus 208Pb one observes the largest octupole collectivity of 34 Weisskopf units (W.u.), which is reduced to 60-70% by the particle-vibration coupling in nuclei which consist of the 208Pb core plus (or minus) a few nucleons. As a consequence of the phonon vibration character of the 3- state, one expects a quadruplet of 2-phonon octupole states with spins and parities 0+, 2+, 4+ and 6+ at about twice the energy of the 1-phonon state. A first scattering experiment suggesting the observation of at least one member of the 2-phonon multiplet was performed via the reaction 208Pb+208Pb at an incident energy well above the Coulomb barrier. In the present experiment the system 208Pb+208Pb has been reinvestigated via Coulomb excitation at a safe bombarding energy at 5.0 MeV/u. The reduced cross-section for the excitation of the octupole states has been compensated by the higher full energy efficiency of five EUROBALL CLUSTER detectors. With the present experimental set-up transition probabilities down to 10-5-10-6 can be measured

  2. Magnetic properties of cyclically deformed austenite

    Science.gov (United States)

    Das, Arpan

    2014-06-01

    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).

  3. The octupoles take pole position

    CERN Multimedia

    2002-01-01

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

  4. AGS correction quadrupoles and octupoles

    International Nuclear Information System (INIS)

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

  5. Magnetic properties of cyclically deformed austenite

    Energy Technology Data Exchange (ETDEWEB)

    Das, Arpan, E-mail: dasarpan1@yahoo.co.in

    2014-06-01

    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 ?{sup /}(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), ?{sup /}(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)??{sup /}(bcc), ?(fcc)? deformation twin ??{sup /}(bcc) and ?(fcc)??{sup /}(bcc). - Highlights: • LCF tests were done at various strain amplitudes of 304LNSS. • Quantification of martensite was done through ferritecope. • Magnetic properties were characterised through VSM. • Correlation of magnetic properties with the cyclic plastic response was done. • TEM was done to investigate the transformation micro-mechanisms.

  6. Magnetic properties of cyclically deformed austenite

    International Nuclear Information System (INIS)

    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). - Highlights: • LCF tests were done at various strain amplitudes of 304LNSS. • Quantification of martensite was done through ferritecope. • Magnetic properties were characterised through VSM. • Correlation of magnetic properties with the cyclic plastic response was done. • TEM was done to investigate the transformation micro-mechanisms

  7. Deformation Properties and Fatigue of Bituminous Mixtures

    OpenAIRE

    Frantisek Schlosser; Jan Mikolaj; Viera Zatkalikova; Juraj Sramek; Dominika Durekova; Lubos Remek

    2013-01-01

    Deformation properties and fatigue performance are important characteristics of asphalt bound materials which are used for construction of pavement layers. Viscoelastic asphalt mixtures are better characterized via dynamic tests. This type of tests allows us to collate materials with regard to axle vibrations which lie usually in the range of 6?Hz–25?Hz for standard conditions. Asphalt modified for heat sensitivity in the range from ?20°C to +60°C has significant impact on the overall charact...

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

    CERN Multimedia

    Hoff, P; Kaczarowski, R

    2002-01-01

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

  9. Octupole shapes and shape changes at high spins in the Z?58, N?88 nuclei

    International Nuclear Information System (INIS)

    The shapes of rotating Xe, Ba, Ce, Nd, and Sm nuclei (84?N?94) are calculated using the cranking model with the Woods-Saxon average potential and pairing. The lightest isotopes of Xe and Ba have nearly spherical ground states, but develop octupole and quadrupole deformations under rotation which remain up to very high spins. The ground states of the heavier isotopes have octupole and quadrupole deformations which persist up to medium spins (I?12?). At higher spins, a shape transition is predicted to reflection-symmetric aligned many-quasiparticle configurations

  10. The properties of Q-deformed hyperbolic and trigonometric functions in quantum deformation

    Science.gov (United States)

    Deta, U. A.; Suparmi

    2015-09-01

    Quantum deformation has been studied due to its relation with applications in nuclear physics, conformal field theory, and statistical-quantum theory. The q-deformation of hyperbolic function was introduced by Arai. The application of q-deformed functions has been widely used in quantum mechanics. The properties of this two kinds of system explained in this paper including their derivative. The graph of q-deformed functions presented using Matlab. The special case is given for modified Poschl-Teller plus q-deformed Scarf II trigonometry potentials.

  11. Deformation properties of thin polymer films

    Science.gov (United States)

    Dion, John Bernard

    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.

  12. Time-dependent Hartree-Fock Study of Octupole Vibrations in doubly magic nuclei

    CERN Document Server

    Simenel, C; Vo-Phuoc, K

    2016-01-01

    Octupole vibrations are studied in some doubly magic nuclei using the time-dependent Hartree-Fock (TDHF) theory with a Skyrme energy density functional. Through the use of the linear response theory, the energies and transition amplitudes of the low-lying vibrational modes for each of the nuclei were determined. Energies were found to be close to experimental results. However, transition amplitudes, quantified by the deformation parameter $\\beta_3$, are underestimated by TDHF. A comparison with single-particle excitations on the Hartree-Fock ground-state shows that the collective octupole vibrations have their energy lowered due to attractive RPA residual interaction.

  13. Optical properties of plastically deformed copper : #an #ellipsometric study

    OpenAIRE

    Rom?evi?, Nebojša; Rudolf, Rebeka; Traji?, J.; Rom?evi?, M.; Hadži?, B.; Vasiljevi?-Radovi?, Dana; Anžel, Ivan

    2012-01-01

    In this paper the results of optical properties investigations on plastically deformed copper are presented. The optical properties of the plastically deformed copper were studied using spectroscopic ellipsometry in the ultraviolet-visible (UV-VIS) range. Chemically pure copper was deformed by applying the Equal Channel Angular Pressing (ECAP) technique. During the last decade, equal-channel angular pressing procedure was used for the fabrication of ultrafine-grained metals and alloys. The pl...

  14. Structure properties of even-even actinides at normal and super deformed shapes analysed using the Gogny force

    International Nuclear Information System (INIS)

    Mean field and beyond mean field methods implemented with the D1S force are used in large scale calculations to study the structure properties of fifty five even-even actinides at normal and isomeric potential deformations. The mass region covered is spanned by the 226-236Th, 228-242U, 232-246Pu, 238-250Cm, 238-256Cf, 242-258Fm and 250-262No nuclides. Hartree-Fock-Bogolyubov (HFB) calculations performed with constraints placed on axial and triaxial quadrupole deformations as well as octupole deformations serve to build tensors of inertia and potential energy landscapes up to very large elongations. Long lived spin isomers are investigated through blocking calculations performed with and without breaking time reversal symmetry. Configuration mixing calculations are performed to make predictions for shape isomers and π=+ vibrations in the isomeric potentials and to calculate moments of inertia at low spin. Moments of inertia are also investigated through cranking HFB calculations to high frequency so as to explore in this regime pairing properties of the D1S force in the heavy mass region. The WKB method is adopted in half-life calculations for the γ-back and fission decay modes of shape isomers. All these predictions are challenged through extensive comparisons with measurements for multipole moments, moments of inertia, spin and shape isomers as well as superdeformed phonons, inner and outer potential barrier heights, and shape isomer lifetimes. Most predictions match the experimental data. Finally we predict a shallow minimum on top of the triaxial inner barriers of N∼154 nuclei. This topological property offers a possible explanation for the unexpected structures observed in fission transmissions measured a long time ago for 252Cf and neighboring nuclei

  15. Some properties of deformed $q$-numbers

    CERN Document Server

    Lobão, Thierry C Petit; Pinho, Suani T R; Borges, Ernesto P

    2009-01-01

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

  16. Corneal biomechanical properties from air-puff corneal deformation imaging

    Science.gov (United States)

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

    2014-02-01

    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.

  17. 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

  18. Influence of deformation technology on fatigue properties of titanium

    OpenAIRE

    Ján Miche?; Marián Buršák; Petra Lacková

    2014-01-01

    The influence of commercially pure Titanium microstructure on fatigue properties and their improvement or deterioration is analyzed in the presented contribution. One tested material was after cold drawing the other after severe plastic deformation by Equal Channel Angular Pressing (ECAP). Intense plastic deformation (ECAP) resulted in yield point 100 % higher and UTS 97% higher than obtained by traditional cold drawing. The ductility was 57% lower than for cold drawing. However, the fatigue ...

  19. Deformation Properties of TiNi Shape Memory Alloy

    OpenAIRE

    Tobushi, H.; LIN, P.; Tanaka, K.; Lexcellent, C.; Ikai, A.

    1995-01-01

    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.

  20. Plastic properties of cold-deformed ironbased sintered materials

    Directory of Open Access Journals (Sweden)

    K. Zar?bski

    2010-07-01

    Full Text Available Cold plastic forming of sintered metal powders has limited practical application because of, among others, the deformation degree andinitial porosity of preforms. Cold forming is combined with a very drastic drop of plastic properties observed in final products. One of the methods that enable regaining the lost plasticity is annealing of sinters after deformation at temperatures above the recrystallisation point. The results of the investigations were presented which aimed at the determination of an effect that the annealing conditions of colddeformed sintered metal powder can have on its structure and mechanical properties. Special attention was drawn to a combined effect of the deformation degree and heat treatment temperature on final plastic properties of the sinters and on their ultimate tensile strength.

  1. Evolution of ground-state quadrupole and octupole stiffnesses in even-even barium isotopes

    Science.gov (United States)

    Wang, Hua-Lei; Yang, Jie; Liu, Min-Liang; Xu, Fu-Rong

    2015-08-01

    Quadrupole and octupole stiffnesses in the ground states of even-even Ba-150112 isotopes have been systematically investigated by means of potential-energy-surface calculations. The calculations are carried out in both (?2,? ,?4 ) and (?2,?3,?4,?5) deformation spaces with the inclusion of triaxial and reflection-asymmetric shape degrees of freedom, respectively. The present results are compared with previous calculations and available experiments. The shape instabilities are evaluated by analyzing the potential energy curves with respect to both the quadrupole and octupole deformations, which is consistent with the previous discussions predicting the ? softness or triaxiality and octupole instability. In addition, taking the near-drip-line 114Ba nucleus as an example, we briefly investigate the effects of potential parameters (e.g., the strength of the spin-orbit potential ? , and the nuclear surface diffuseness a ) on the deformation energy curve, showing almost negligible modifications of nuclear shape and stiffness but considerable changes in the depth of the minimum and the height of the fission barrier (which may be very important for the study of heavy and superheavy nuclei).

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

    Science.gov (United States)

    Dey, Sanjib

    2015-02-01

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

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

    CERN Document Server

    Dey, Sanjib

    2015-01-01

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

  4. Magnetic properties of single-domain powders after plastic deformation

    International Nuclear Information System (INIS)

    Magnetic properties of fine-dispersed powders of nickel, fcc cobalt and Co-alloys containing 46 and 51 weight % have been investigated. Single-domain powder plastic deformation proved to lead to magnetic property changes in fcc and hcp transformation materials (nickel-Co). In isotropic samples residual magnetisation magnitude and powder coercitivity strength are decreasing, alongside with a shift of hysteresis frequent cycles along the axis of ordinates. In structural samples residual magnetisation anisotropy is increasing. It points to the uniaxial anisotropy appearing in particles. A crystal structure model of deformed particles is presented which provide magnetic uniaxiality

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

    DEFF Research Database (Denmark)

    Jakobsen, Bo

    2006-01-01

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

  6. Study of the octupole modes in the atomic nucleus of 156Gd: experimental search of the tetrahedral symmetry

    International Nuclear Information System (INIS)

    Geometrical symmetries play an important role in the understanding of all physical systems. In nuclear structure they are linked to the shape of the mean-field used to describe the atomic nuclei properties. In the framework of this thesis, we have used the predictions obtained with the help of the nuclear mean-field Hamiltonian with the Universal Woods-Saxon potential to study the effects of the so-called 'High-Rank' symmetries. These point-group symmetries lead to a nuclear state degeneracy of the order of 4. It is predicted that the tetrahedral symmetry affects the stability of nuclei close to the tetrahedral magic numbers [Z,N]=[32,40,56,64,70,90-94,136]. We have selected the Rare-Earth region close to the tetrahedral doubly magic nucleus 154Gd for our study. In this region, there exists negative parity structures poorly understood. Yet the tetrahedral symmetry, as related to a non-axial octupole deformation, breaks the reflection symmetry and leads to the negative parity states. Following a systematics of experimental properties of the nuclei in this region, we have selected 156Gd as the object of our study for the octupole excitation modes. We have used the reduced transitions probabilities to discriminate between these modes. To achieve this goal, we have performed three gamma spectroscopy experiments at the ILL in Grenoble with the EXILL and GAMS detectors to measure the lifetimes and the gamma transition intensities from the candidate states. The analysis of our results shows that including the tetrahedral shape helps to understand the dipole transition probabilities. This result will open new experimental and theoretical perspectives. (author)

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

    International Nuclear Information System (INIS)

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

  8. Deformation bands in porous sandstones their microstructure and petrophysical properties

    Energy Technology Data Exchange (ETDEWEB)

    Torabi, Anita

    2007-12-15

    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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-08-01

    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.

  10. Experimental fusion barrier distributions reflecting projectile octupole state coupling to prolate and oblate target nuclei

    International Nuclear Information System (INIS)

    Fusion excitation functions have been measured spanning the entire barrier region in 1 MeV energy steps for the two systems 40Ca+192Os,194Pt. Precautions were taken to ensure sufficiently small errors to allow for extraction of the distribution of fusion barriers from the second differential of the product of E and ?. These results are compared with coupled channels calculations which take into account the most important degrees of freedom of both projectile and target. The influence of the prolate deformation of 192Os and the oblate deformation of 192Pt as well as the octupole vibration of 40Ca is apparent. copyright 1996 The American Physical Society

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

    OpenAIRE

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

    2010-01-01

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

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

    DEFF Research Database (Denmark)

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

    2010-01-01

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

  13. Processing microstructure property relationships in severely deformed tantalum

    International Nuclear Information System (INIS)

    Bars of as-cast, large grained and highly textured Ta were deformed by multipass equal channel angular extrusion (ECAE) at room temperature to strains of 4.6 through 90 deg. die-angle tooling. The ability of ECAE processing to produce a uniform fine-grained microstructure with homogenous deformation characteristics is investigated. Comparisons of the microstructure and mechanical properties after four consecutive extrusions via route C (180 deg. rotation between passes) and E (2C, 90 deg. rotation then 2C) are made in both the as-worked (submicron-scale grains) and recrystallized (micron-scale grains) states. It is shown that the as-worked grain size levels out at 200-300 nm after four passes. The recrystallized grain size after two to four passes is ?10-15 ?m with microstructural uniformity that is dependent on the microstructural uniformity in the starting material. It is also demonstrated that four pass ECAE processing of as-cast large grained BCC materials is not necessarily enough to homogenize texture. A pre-processing step with combined severe plastic deformation and recrystallization improves microstructural uniformity and lessens texture gradients in subsequent deformation processing steps

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

    Directory of Open Access Journals (Sweden)

    S.J. Pawlak

    2008-07-01

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

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

    OpenAIRE

    Calvo, Florent; Champenois, Caroline; YURTSEVER, Ersin

    2009-01-01

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

  16. 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

  17. Octupole deformation in neutron-rich barium isotopes

    International Nuclear Information System (INIS)

    Partial decay schemes for the very neutron-rich nuclei /sup 142,144/Ba and /sup 146/Ba have been determined by the study of ?-? coincidences in /sup 252/Cf fission fragments. Interlaced positive- and negative-parity levels connected by fast electric dipole transitions are observed in /sup 144/Ba and /sup 146/Ba above spin 7h. This is similar to the situation in some light actinide nuclei, where the data have been interpreted in terms of reflection-asymmetric shapes

  18. Octupole correlations in neutron rich, odd-A lanthanum nuclei

    International Nuclear Information System (INIS)

    Neutron-rich, odd-Z nuclei 145La and 147La populated in spontaneous fission of 248Cm were studied using the EUROGAM array. The experiment indicates the presence of similar octupole correlations in the studied La isotopes as found in the barium core nuclei. Alternating-parity structures were found in 145La, indicating enhanced octupole correlations, as observed in 144Ba, while in 147La octupole effects are weakened by alignment phenomena, as seen in the core nucleus 146Ba. copyright 1996 The American Physical Society

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

    CERN Document Server

    Nomura, K; Robledo, L M

    2015-01-01

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

  20. Ground state octupole correlation energy with effective forces

    Science.gov (United States)

    Robledo, L. M.

    2015-05-01

    The ground state octupole correlation energy is computed with the D1M variant of the Gogny force in different theoretical frameworks and analyzed in detail. First I consider the correlation energy gained at the mean field level by breaking reflection symmetry. Next I consider the energy gain coming from symmetry (parity) restoration and finally I analyze the ground state correlation energy after configuration mixing with axially symmetric octupole states. The impact of the latter on theoretical binding energies indicates that octupole correlations do not affect in a significant way the trend and systematic of binding energies and therefore can not improve the performance of theoretical models in this respect. In particular, the too-large ‘shell gaps’ predicted by self-consistent mean field models and relevant in astrophysics scenarios are not altered by the octupole correlations.

  1. Ground state octupole correlation energies with effective forces

    OpenAIRE

    Robledo, Luis M.

    2014-01-01

    The ground state octupole correlation energy is computed with the D1M variant of the Gogny force in different theoretical frameworks and analyzed in detail. First I consider the correlation energy gained at the mean field level by breaking reflection symmetry. Next I consider the energy gain coming from symmetry (parity) restoration and finally I analyze the ground state correlation energy after configuration mixing with axially symmetric octupole states. The impact of the l...

  2. Large ferroquadrupole moment induced in the octupole-ordered Ce0.7La0.3B6 revealed by high-resolution x-ray diffraction

    Science.gov (United States)

    Inami, T.; Michimura, S.; Hayashi, Y.; Matsumura, T.; Sera, M.; Iga, F.

    2014-07-01

    We carried out a high-resolution x-ray diffraction experiment on Ce0.7La0.3B6 that exhibits staggered order of 4f octupole moments below TO=1.4 K. Theoretically, ferroquadrupole moments that accompany the antiferro-octupole order and a resultant rhombohedral deformation of the cubic lattice were predicted. In contrast, experimentally, no direct evidence of the rhombohedral lattice has been obtained. We observe the splitting of Bragg peaks below TO and find that the unit cell is a rhombohedron being elongated along the [111] axis. The response of rhombohedral domains to magnetic fields also well agrees with theoretical calculations. A particular outcome of this experiment is that the magnitude of the induced quadrupole moments is precisely evaluated from the obtained shear strain. Using this result, the magnitude of the hidden octupole moments is also discussed.

  3. 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1978-03-01

    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 600/sup 0/F (589/sup 0/K) to 2200/sup 0/F (1477/sup 0/K) with the emphasis on the 800/sup 0/F (700/sup 0/K) to 2000/sup 0/F (1366/sup 0/K) temperature levels in low pressure air (6.5 x 10/sup -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.

  5. 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

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

    International Nuclear Information System (INIS)

    The evolution of crystallographic texture in a nanocrystalline nickel–20 wt% cobalt alloy has been investigated for deformation up to large strains. The effect of texture on magnetic properties has been evaluated. The material shows characteristic copper-type texture at large strain levels. Microstructural examinations indicate that the evolution of texture is assisted by deformation-induced grain growth. The values of saturation magnetization and coercivity have been correlated with the crystallographic texture and grain size. - Highlights: • The deformation of a nanocrystalline nickel-20 wt% cobalt alloy, to large strains, leads to a characteristic copper-type rolling texture. • Dislocation based slip process is evident from the deformed microstructures at the later stages of deformation, while grain boundary assisted mechanisms are active during the initial stages. • The activity of dislocation at higher strain levels is facilitated by deformation-induced grain growth. • The evolution of magnetic properties is dependent on the deformation texture, while the effect of grain size is insignificant

  7. Microstructural aspects of microheterogeneous deformation and mechanical properties of Ni-Ti based alloys

    International Nuclear Information System (INIS)

    The results of the comprehensive research of the deformation micropicture and mechanical properties of Ni-Ti based alloys are presented. The research of the microheterogeneous deformation on the small bases with the smallest base of 10 micron were made with the help of the elaborated automation method of the deformation measurement in the comparison with different metals. Mechanical properties had been studied on the basis of the deformation diagram research on the results of the deformation measurement with the precision up to 3.10-5. The distinctive peculiarities of the microheterogeneous deformation of Ni-Ti based alloys were established. The process of the deformation in the microvolumes is extremely heterogeneous. The microheterogeneity of the residual microdeformation distribution is being preserved with the full restoration of the shape under the temperature influence. This explains the difference in mechanical properties of alloys in their proper state and after deformation and restoration of shape. It is shown that deformation of alloys takes place on the account of shifting processes and martensitic transformations. The relation between these micromechanisms of deformations depends on the value of deformation. Heterogeneity of distribution of microdeformation causes the appearance of elastic hysteresis and change of elasticity module in the process of loading and unloading. (orig.)

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

    DEFF Research Database (Denmark)

    Jakobsen, Bo

    2006-01-01

    asymmetrical line broadening have to be reconsidered. Based on continuous deformation experiments, it is found that the dislocation patterning takes place during the deformation, and that a subgrain structure appears from the moment where plastic deformation is detected. By investigating samples under stress......-radiation based technique High Angular Resolution 3DXRD has been developed at the 1-ID beam-line at the Advanced Photon Source. The technique extents the 3DXRD approach, to 3D reciprocal space mapping with a resolution of ≈ 1 · 10−3Å−1 and allows for in-situmapping of reflections from deeply-embedded individual...... width of the peaks, and spatial scanning experiments it is concluded that the individual peaks arise from individual dislocation-free regions (the subgrains) in the dislocation structure. The cloud is attributed to the dislocation rich walls. Samples deformed to 2% tensile strain were investigated under...

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

    CERN Document Server

    Calvo, Florent; Yurtsever, Ersin

    2009-01-01

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

  10. Deformation

    Directory of Open Access Journals (Sweden)

    RahulPandit

    2014-06-01

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

  11. A Heisenberg Ferromagnet With Biquadratic and Dipol-octupol Interactions

    Science.gov (United States)

    Ba?k, Z.

    1981-08-01

    A Heisenberg S - 3/2 ferromagnet with isotropic biquadratic exchange and dipole-octupol coupling is discussed. The conditions for the exact ferromagnetic ground state are derived. The thermodynamical behaviour in the molecular field approximation is discussed. Collective excitation spectra and the 1/z correction to the free energy are found.

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

    International Nuclear Information System (INIS)

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

  13. Measurement of tune spread in the Tevatron versus octupole strength

    International Nuclear Information System (INIS)

    A experiment was performed in the Tevatron to measure the tune spread versus octupole strength. The experiment is sensitive to the relationship between octupole strength and current in the T:OZF circuit and to the octupole (and other non-linear focusing fields) in the Tevatron. The major motivation for the experiment was to determine the value of octupole excitation that minimizes the tune spread: this value is an estimate of the value required to obtain ''zero'' total octupole excitation in the extraction process. The experiment was performed using the strip-line kickers at A17 and the resonant Schottky pickups. The horizontal proton kicker was excited with a sine-wave from a vector signal analyzer (HP-89440A) and the horizontal proton signal was received. The gating circuitry normally used to select proton or antiproton bunches was by-passed. The response function was measured and recorded on a floppy disk. Measurements were initially made with a 200 Hz span (0.250 Hz frequency bins) and later with a 100 Hz span (0.125 Hz frequency bins). The data was all obtained at flattop (800 GeV) with Q39S and Q39C set to correct the 1/2 integer stop band and QXR (the extraction regulation system) turned off. No attempt was made to examine sensitivity to closed orbit, chromaticity, or any other machine parameters other than the zero harmonic octupoles. The tune varied slightly (presumably because of feed-down effects from the octupoles), but was approximately constant at 19.472 (only the fractional part was measured). The beam emittance was not measured because the flying wires were not working when these data were taken. The analysis of the data was accomplished by replotting the data from the floppy disk. The peak amplitude and the full width at 25% of the peak height were measured. Figures 1-7 show some of the data that was obtained. The vertical scales in figures 1-7 are adjusted so that the data span 80% of the full height of the screen. The hardware requires the markers to be measured points, so the width measured is not exactly at 25% of full height

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Yavshits S.

    2010-03-01

    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.

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

    Czech Academy of Sciences Publication Activity Database

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

    2015-01-01

    Ro?. 17, ?. 5 (2015), s. 3715-3722. ISSN 1463-9076 Institutional support: RVO:68081723 Keywords : physical properties * plastic deformation * TEM, SEM Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.493, year: 2014

  17. Food gels filled with emulsion droplets : linking large deformation properties to sensory perception

    OpenAIRE

    Sala, G.

    2007-01-01

    Key words: polymer gels, particle gels, emulsion, large deformation, friction, sensory   This thesis reports studies on the large deformation and lubrication properties of emulsion-filled gels and the way these properties are related to the sensory perception of the gels. The design of the studies included polymer and particle gels containing oil droplets of which the interaction with the gel matrix was varied, resulting in droplets either bound or unbound to the matrix. The unique combinatio...

  18. Properties of interfaces and plastic deformation in TiAl.

    Czech Academy of Sciences Publication Activity Database

    Paidar, Václav

    Brno, 2001, s. 424-428. ISBN 80-214-1892-3. [International Conference MSMF /3./. Brno (CZ), 27.06.2001-29.06.2001] Institutional research plan: CEZ:AV0Z1010914 Keywords : intermetallic compounds * modes of plastic deformation * superlattice dislocations * twinning * lamellar microstructure * grain boundaries * compatibility stresses Subject RIV: BM - Solid Matter Physics ; Magnetism

  19. Concentration and deformation dependences of Mo-Cu and Mo-Ni-Cu composites mechanical properties

    International Nuclear Information System (INIS)

    Mechanical properties of sintered composites were investigated in dependence on phase composition and deformation. The ultimate strength and yield limit of Mo-Cu and Mo-Cu-Ni compositions do not depend on the reinforcing phase volume. It is shown that plastic deformation of these materials leads to an increase in their strength and plasticity; the strengthening process occurs in several stages. It is found out that when the deformation degree is above 90%, the strengthening coefficient is on the average thrice as high; anisotropy of mechanical properties is practically absent; the character of their dependence on the volume of the reinforcing particles remains unchanged

  20. Mechanical properties of hot deformed Inconel 718 and X750

    Directory of Open Access Journals (Sweden)

    A. Nowotnik

    2012-02-01

    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.

  1. Mechanical properties of hot deformed Inconel 718 and X750

    OpenAIRE

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

    2012-01-01

    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...

  2. Properties of interfaces and plastic deformation in TiAl.

    Czech Academy of Sciences Publication Activity Database

    Paidar, Václav

    Brno : x, 2001 - (Šandera, P.), s. 759-766 ISBN 80-214-1892-3. [International Conference on Materials structure and Micromechanics of Fracture /3./. Brno (CZ), 27.06.2001-29.06.2001] R&D Projects: GA AV ?R IAA1010817; GA MŠk ME 190 Institutional research plan: CEZ:AV0Z1010914 Keywords : intermetallic compounds * modes of plastic deformation * superlattice dislocations * twinning * lamellar microstructure * grain boundaries Subject RIV: BM - Solid Matter Physics ; Magnetism

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1980-05-01

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

  4. Influences of cyclic deformation on creep property and creep-fatigue life prediction considering them

    International Nuclear Information System (INIS)

    Evaluation of creep-fatigue is essential in design and life management of high-temperature components in power generation plants. Cyclic deformation may alter creep property of the materials and its consideration may improve predictability of creep-fatigue failure life. To understand them, creep tests were conducted for the materials subjected to cyclic loading and their creep rupture and deformation behaviors were compared with those of as-received materials. Both 316FR and modified 9Cr-1Mo steel were tested. (1) Creep rupture time and elongation generally tend to decrease with cyclic loading in both materials, and especially elongation of 316FR drastically decreases by being cyclically deformed. (2) Amount of primary creep deformation decreases by cyclic loading and the ways to improve its predictability were developed. (3) Use of creep rupture ductility after cyclic deformation, instead of that of as-received material, brought about clear improvement of life prediction in a modified ductility exhaustion approach. (author)

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

    International Nuclear Information System (INIS)

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

  6. Deslocation structure and mechanical properties of ?-iron in dependence on plastic deformation conditions

    International Nuclear Information System (INIS)

    Investigations of dislocation structure and mechanical properties of iron after rolling deformation in shaped rolls and after hydroextrusion are conducted. It is shown that dislocation iron structure slightly changes with deformation degree after rolling in shaped rolls and annealing and it is characterized by low density of screw dislocations. Cold brittleness temperature decreases in the result of rolling and the succeeding recrystallization and impact strength increases both at room temperature and at low temperatures. Screw dislocations having high Peierls barrier prevail in the structure after hydroextrusions. The iron deformed by hydroextrusion at 400 mPa and higher after annealing has high cold brittleness temperature and low impact strength

  7. Deformation and elastic properties of WC-Co hard alloys during micro- and macroindentation

    International Nuclear Information System (INIS)

    Deformation properties of the alloys and their components are studied during micro- and macroindentation, with recording the penetration strength-depth diagram. Specimens of hard tungsten alloys with 4-98 wt.%Co are studied. Deformation work of the WC-Co alloys during micro- and macroindentation is determined and its variation depending on the cobalt phase content is studied. The work of deformation during constant depth of indentor penetration is shown to be a sensitive characteristics with respect to the structure of hard tungsten alloys

  8. 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)

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

    International Nuclear Information System (INIS)

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

  10. 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

  11. Alignment of the K = 2- octupole and ground-band angular momenta in 180W

    International Nuclear Information System (INIS)

    Excitation of the K = 2- octupole band up to the 14- member in the reaction 181Ta(p, 2n?)180W shows an odd-even energy staggering. This staggering can be interpreted in terms of different Coriolis-induced alignments of the rotational and octupole vibrational angular momenta for the odd- and even-spin members of the K = 2- octupole band. There is no evidence that the K = 2- octupole vibration decomposes into two-quasiparticle decoupled states even at the highest spins observed

  12. 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

  13. Microstructure and local mechanical property evolution during high strain-rate deformation of tantalum

    Directory of Open Access Journals (Sweden)

    Vachhani Shraddha J.

    2015-01-01

    Full Text Available Shear localization is often a failure mechanism in materials subjected to high strain rate deformation. It is generally accepted that the microstructure evolution during deformation and the resulting heterogeneities strongly influence the development of these shear bands. Information regarding the development of local mechanical heterogeneities during deformation is difficult to characterize and as such, constitute is a critical missing piece in current crystal plasticity models. With the recent advances in spherical nanoindentation data analysis, there is now an unprecedented opportunity to obtain insights into the change in local mechanical properties during deformation in materials at sub-micron length scales. In this work, we quantify the evolution of microstructure and local mechanical properties in tantalum under dynamic loading conditions (split Hopkinson pressure bar, to capture the structure- property correlations at the sub-micron length scale. Relevant information is obtained by combining local mechanical property information captured using spherical nanoindentation with complimentary structure information at the indentation site measured using EBSD. The aim is to gain insight into the role of these microstructural features during macroscopic deformation, particularly their influence on the development of mechanical heterogeneities that lead to failure.

  14. Microstructure and local mechanical property evolution during high strain-rate deformation of tantalum

    Science.gov (United States)

    Vachhani, Shraddha J.; Mara, Nathan; Livescu, Veronica; Cerreta, Ellen

    2015-09-01

    Shear localization is often a failure mechanism in materials subjected to high strain rate deformation. It is generally accepted that the microstructure evolution during deformation and the resulting heterogeneities strongly influence the development of these shear bands. Information regarding the development of local mechanical heterogeneities during deformation is difficult to characterize and as such, constitute is a critical missing piece in current crystal plasticity models. With the recent advances in spherical nanoindentation data analysis, there is now an unprecedented opportunity to obtain insights into the change in local mechanical properties during deformation in materials at sub-micron length scales. In this work, we quantify the evolution of microstructure and local mechanical properties in tantalum under dynamic loading conditions (split Hopkinson pressure bar), to capture the structure- property correlations at the sub-micron length scale. Relevant information is obtained by combining local mechanical property information captured using spherical nanoindentation with complimentary structure information at the indentation site measured using EBSD. The aim is to gain insight into the role of these microstructural features during macroscopic deformation, particularly their influence on the development of mechanical heterogeneities that lead to failure.

  15. Mechanical properties of steel 20 at small deformations

    Science.gov (United States)

    Mytsyk, B. G.; Kost', Ya. P.; Turko, B. I.; Gas'kevich, G. I.

    2015-08-01

    The elastic hysteresis and residual deflections of samples made of steel 20, which correspond to the model of a thin rigid round plate pinched over the contour, have been investigated. It has been shown that annealing of the samples at 470 and 670 K weakly affects these characteristics, while after complete annealing (1170 K), the aging of steel 20 for three days is accompanied by a decrease in amplitude ? h of the elastic hysteresis by ˜20%. A postulate that there is no elasticity limit of metals, below which residual deformation would be absent, has been confirmed experimentally. It has been shown that, based on the values of ? h , the ultimate strength of metals can be estimated acting on the samples by stresses smaller than the yield stress by an order of magnitude. A giant increase (by a factor of ˜2.5) in ? h has been found after a prolonged (for 2 months) aging of steel 20 after the diffusion of hydrogen from it, which indicates the corresponding decrease in its cyclic longevity.

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

    Science.gov (United States)

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

    2015-01-01

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

  17. Petrophysical properties of deformation bands and their influence on fluid flow in carbonate grainstones: insights from the Maghlaq Fault, Malta.

    OpenAIRE

    Fossmark, Heidi Synnøve Solli

    2015-01-01

    Deformation bands are tabular, sub- centimeter thick zones, which accommodates shear and/or volumetric deformation. Only a few examples of deformation bands have been documented in porous carbonate rocks, and the knowledge about how petrophysical properties and fluid flow interacts in such settings is thus limited. Motivated by this, the current study focus on deformation bands found in carbonate grainstones in the hangingwall of an extensional fault on the southwestern c...

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

    Science.gov (United States)

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

    2008-11-01

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

  19. Ambipolar electric fields and turbulence studies in the Wisconsin levitated toroidal octupole

    International Nuclear Information System (INIS)

    Detailed studies of hot ion plasmas (T/sub i/ > T/sub e/) in the poloidal field octupole show that the ambipolar electric field which is perpendicular to the flux surfaces is well explained by the observed properties of the microturbulence structures in the plasma. The turbulence structure has been measured by correlation techniques which are carefully described. In these experiments, signals were studied which are aperiodic in time and space, short lived compared to the decay times of the bulk plasma parameters, short ranged compared to the machine size, and are therefore classified as microturbulence structures. The resulting spatial and temporal correlation functions (CFs) are well fitted to a Gaussian function and the associated correlation lengths or times are the half width at half maximum of the CFs. The correlation length is measured to be the ion gyro radius for the hot hydrogen plasma and somewhat less for the helium plasma

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

    CERN Document Server

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

    2013-01-01

    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.

  1. High-spin octupole yrast levels in 216Rn86

    International Nuclear Information System (INIS)

    The yrast level structure of 216Rn has been studied using in-beam spectroscopy ?-?-? coincidence techniques through the 208Pb(18O, 2?2n) reaction in the 91-93 MeV energy range, using the 8? GASP-ISIS spectrometer at Legnaro. The level scheme of 216Rn resulting from this study shows alternating parity bands only above a certain excitation energy. From this result, the lightest nucleus showing evidence of octupole collectivity at low spins is still 216Fr, thereby defining the lowest-mass corner for this kind of phenomenon as N?129 and Z?87

  2. Design of an electrostatic octupole for micro-beam deflection

    International Nuclear Information System (INIS)

    In electrostatic deflection of focused ion and electron beams, a homogeneous field should be maintained within the deflector to reduce aberrations. The geometrical and voltage conditions are investigated to produce an electric field as homogeneous as possible within an octupole deflector. If the eight electrodes are equally shaped into a triangular cross section and are directed as one edge of each electrode with an angle of 3600/8 showing to the center of the device, then the adjacent electrode faces form parallel plate capacitors and the resulting field is the best fit to the ideal cosine potential distribution at the inner circle of the electrodes. (author)

  3. Optical properties of plastically deformed copper: an ellipsometric study: Opti?ne lastnosti plasti?no derformiranega bakra: študij elipsometrije:

    OpenAIRE

    Anžel, Ivan; Hadži?, Branka; Rom?evi?, Maja J.; Rom?evi?, Nebojša; Rudolf, Rebeka; Traji?, Jelena; Vasiljevi?-Radovi?, Dana

    2011-01-01

    In this paper the results of optical properties investigations on plastically deformed copper are presented. The optical properties of the plastically deformed copper were studied using spectroscopic ellipsometry in the ultraviolet-visible (UV-VIS) range. Chemically pure copper was deformed by applying the Equal Channel Angular Pressing (ECAP) technique. During the last decade, equal-channel angular pressing procedure was used for the fabrication of ultrafine-grained metals and alloys. The pl...

  4. Octupole correlation effects in 151Pm

    International Nuclear Information System (INIS)

    Excited states of 151Pm have been observed using the 150Nd(?,p2n) reaction at a beam energy of 35 MeV. Levels with spin up to 19/2 have been seen in a positive parity band built on the 5/2+ ground state, and up to 21/2 in a negative parity band built on the 5/2- level at 117 keV excitation energy. Levels of the same spin but opposite parity are nearly degenerate and there are strong (?1.1x10-3 W.u.) electric dipole transitions between members of the two bands. The energy staggering of levels and their electromagnetic decay properties are somewhat different for the two bands

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

    Directory of Open Access Journals (Sweden)

    Alexander I. Khaimovich

    2014-10-01

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

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

    OpenAIRE

    Alexander I. Khaimovich; Andrey V. Balaykin

    2014-01-01

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

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

    CERN Document Server

    Kubo, K; Kubo, Katsunori; Kuramoto, Yoshio

    2003-01-01

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

  8. Microstructure, elastic properties and deformation mechanisms of horn keratin.

    Science.gov (United States)

    Tombolato, Luca; Novitskaya, Ekaterina E; Chen, Po-Yu; Sheppard, Fred A; McKittrick, Joanna

    2010-02-01

    The structure and mechanical properties of the horns from a desert bighorn sheep, Ovis canadensis, were examined. Horns must be strong and durable as they are subjected to extreme loading impacts, making them superior structural materials. Horns are composed of alpha-keratin, a fibrous, structural protein found in hair, nails, claws and hooves. Horns have a lamellar structure (2-5microm in thickness) stacked in the radial direction with tubules (approximately 40x100microm in diameter) dispersed between the lamellae, extending along the length of the horn in the growth direction. Compression and bending tests were conducted in both rehydrated and ambient dried conditions. The yield strength and elastic modulus are anisotropic and are correlated with the orientation of the tubules. Rehydrated samples showed significant loss of strength and modulus. Microscopy of fractured samples revealed several toughening mechanisms: delamination and ligament bridging in bending and delamination and microbuckling of the lamellae in compression. PMID:19577667

  9. Symmetries and deformations in the spherical shell model

    CERN Document Server

    Van Isacker, Piet

    2016-01-01

    We discuss symmetries of the spherical shell model that make contact with the geometric collective model of Bohr and Mottelson. The most celebrated symmetry of this kind is SU(3), which is the basis of Elliott's model of rotation. It corresponds to a deformed mean field induced by a quadrupole interaction in a single major oscillator shell N and can be generalized to include several major shells. As such, Elliott's SU(3) model establishes the link between the spherical shell model and the (quadrupole component of the) geometric collective model. We introduce the analogue symmetry induced by an octupole interaction in two major oscillator shells N-1 and N, leading to an octupole-deformed solution of the spherical shell model. We show that in the limit of large oscillator shells (large N) the algebraic octupole interaction tends to that of the geometric collective model.

  10. Symmetries and deformations in the spherical shell model

    Science.gov (United States)

    Van Isacker, P.; Pittel, S.

    2016-02-01

    We discuss symmetries of the spherical shell model that make contact with the geometric collective model of Bohr and Mottelson. The most celebrated symmetry of this kind is SU(3), which is the basis of Elliott’s model of rotation. It corresponds to a deformed mean field induced by a quadrupole interaction in a single major oscillator shell N and can be generalized to include several major shells. As such, Elliott’s SU(3) model establishes the link between the spherical shell model and the (quadrupole component of the) geometric collective model. We introduce the analogue symmetry induced by an octupole interaction in two major oscillator shells N-1 and N, leading to an octupole-deformed solution of the spherical shell model. We show that in the limit of large oscillator shells, N\\to ? , the algebraic octupole interaction tends to that of the geometric collective model.

  11. The change in microstructure and mechanical properties on hot torsional deformation of BT9 titanium alloy

    International Nuclear Information System (INIS)

    The influence of temperature, strain rate and percentage reduction on mechanical properties and laminated microstructure evolution is studied for a two-phase titanium alloy VT9 (Ti-6.5Al-3.5Mo-1.6Zr-0.27Si) under hot deformation by torsion. It is revealed that the nature of the change of yield stresses under deformation as well as the margin of plasticity are conditioned by microcrystalline structure formation and are determined not only by temperature and strain rate conditions but also by specific features of torsional deformation. The degree of structural transformation is shown to be considerably lower under torsion compared to tension in spite of a higher level of residual strain

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

    International Nuclear Information System (INIS)

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

  13. 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

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

    CERN Document Server

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

    2002-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Mart SAARNA

    2012-12-01

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

  16. Effect of viscosity of petroleum products on deformation properties of concrete

    Directory of Open Access Journals (Sweden)

    A.P. Svintsov

    2014-11-01

    Full Text Available This paper presents the results of studies of the effect of petroleum products, impregnating in concrete, on its deformation properties. Petroleum products, impregnating in concrete and reinforced concrete structures, have a negative impact on their strength and deformation characteristics. The negative impact of petroleum products on concrete and reinforced concrete is associated with changes in the hydration process of cement, as well as changes in the structure of the concrete. Strength and deformation characteristics of concrete change due to hydraulic pressure of petroleum products in the pores exerted on the skeleton of cement stone. In this aspect, the crucial point is the porosity of concrete as a permeability factor for petroleum products. One of the most important factors affecting the physical and mechanical characteristics of oil-impregnated concrete is their viscosity. In this paper, the mathematical description of the change of deformation depending on the relative viscosity of impregnating of petroleum products, the value of the axial load and the concrete class was proposed. The obtained results allow assessing changes in deformation characteristics of load-bearing concrete and reinforced concrete of industrial buildings, where petroleum products are used in the technological processes.

  17. Effects of recrystallization on texture, microstructure and mechanical properties in HPT-deformed pure Mg

    Energy Technology Data Exchange (ETDEWEB)

    Bonarski, Bartlomiej J; Schafler, Erhard; Zehetbauer, Michael J [Research Group Physics of Nanostructured Materials, Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Wien (Austria); Mikulowski, Borys, E-mail: bartlomiej.bonarski@univie.ac.a [Department of Metallic Materials and Nanotechnology, Faculty of Non-Ferrous Metals, AGH - University of Science and Technology, Al. Mickiewicza 30/A-2, PL-30059 Krakow (Poland)

    2010-07-01

    Mg of purity 99.8 wt% was deformed by High Pressure-Torsion at hydrostatic pressures 1 to 4 GPa and RT, up to plastic shear strains of 120. X-ray texture analysis showed up deviations from expected shear texture, which increased with increasing shear strain and hydrostatic pressure. According to TEM and SEM investigations these deviations can be understood in terms of recrystallization. The current paper aimed at the differences of the recrystallization processes which occur during HPT deformation and unloading (dynamic recrystallization, DRX), and those after deformation (static recrystallization, SRX). For this purpose, two sorts of samples were investigated: (i) such being stored at RT immediately after HPT deformation, and (ii) such being stored at 77 K immediately after HPT deformation, and stored at RT for a minimum and constant time needed for preparation. The results show that SRX brings the texture closer to the ideal shear texture and to higher strength values, but to smaller ductilities than DRX does. The mechanical properties can be attributed to changes of texture rather than to those of grain size.

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

    Directory of Open Access Journals (Sweden)

    Ratjkova E. I.

    2013-07-01

    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.

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.

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

    Science.gov (United States)

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

    2010-09-01

    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.

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Popp, T.; Salzer, K. [Institut fur Gebirgsmechanik GmbH, Leipzig (Germany)

    2005-07-01

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

  4. 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

  5. Changes in structure and properties of austenitic steel during hot deformation

    International Nuclear Information System (INIS)

    The changes of structure and properties of the 12Kh18N10T steel have been studied during hot deformation by tension. Property changes have been judged by the form of the s-n diagram curve in the true-stress-true strain coordinates. Structure has been studied by the methods of optical and electron microscopy. It is shown that the initial stages of hardening of the hot-deformed austenite (epsilon = 20-25% is the development of the dynamic recrystallization which occurs by the way of subgrain coalescence. The increased dislocation density in recrystallized volumes and the formation of new mean- and high angular boundaries provides the summary hardening of austenite, in spite of the development of dynamic recrystallization processes

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

    Science.gov (United States)

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

    2012-11-01

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

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

    OpenAIRE

    Maharaj, Dave; Bhushan, Bharat

    2014-01-01

    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 p...

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

    DEFF Research Database (Denmark)

    Fugl, Andreas Rune; Jordt, Andreas; Petersen, Henrik Gordon; Willatzen, Morten; Koch, Reinhard

    2012-01-01

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

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

    Science.gov (United States)

    Reed, R. P.

    1972-01-01

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

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

    OpenAIRE

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

    2007-01-01

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

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

    Czech Academy of Sciences Publication Activity Database

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

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

  12. Periodic-Orbit Bifurcation and Shell Structure in Reflection-Asymmetric Deformed Cavity

    OpenAIRE

    Sugita, A.; Arita, K; Matsuyanagi, K

    1997-01-01

    Shell structure of the single-particle spectrum for reflection-asymmetric deformed cavity is investigated. Remarkable shell structure emerges for certain combinations of quadrupole and octupole deformations. Semiclassical periodic-orbit analysis indicates that bifurcation of equatorial orbits plays an important role in the formation of this new shell structure.

  13. Plasma resistivity measurements in the Wisconsin levitated octupole

    International Nuclear Information System (INIS)

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

  14. Effect of thermomechanical conditions of deformation on structure and properties of tungsten wire

    International Nuclear Information System (INIS)

    The purpose of the investigation is to specify the relation between conditions of plastic deformation of non-slacked tungsten, structure and properties of rods and wire. Planning multifactor experiments is chosen as the basic method for investigation. It is shown that rationai choice of plastic working conditions permits to reduce the tendency to lamination of tungsten wire. Growth of wire ductility is followed by decrease of its residual electroresistance. Rapid porocedure of return due to precipitation of dissolved admixtures is the main reason for improving plastic properties of the wire

  15. Structural and mechanical properties of nanocrystalline titanium processed by severe plastic deformation

    Energy Technology Data Exchange (ETDEWEB)

    Popov, A.A.; Pyshmintsev, I.Y.; Demakov, S.L.; Illarionov, A.G. [Ural State Technical Univ., Ekaterinburg (Russian Federation); Lowe, T.C. [Los Alamos National Lab., NM (United States); Sergeyeva, A.V.; Valiev, R.Z. [Ufa State Aviation Technical Univ. (Russian Federation). Inst. of Advanced Materials Physics

    1997-10-01

    Recent investigations have demonstrated that materials with ultrafine grain (UFG) structure (nano- and submicron crystalline) can be processed by severe plastic deformation. One advantage of this method is that it can be applied to both pure metals and alloys. Moreover, it produces samples that have no residual porosity so that meaningful measurements of the physical and mechanical properties are possible. Investigations of ultrafine grain copper and aluminum alloys have revealed a number of specific features of their mechanical behavior, namely extremely high hardness and strength, the absence of strain hardening, and deviation form the Hall-Petch relationship. In this work the authors investigate the mechanical properties and thermal stability of UFG titanium.

  16. 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)

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

    International Nuclear Information System (INIS)

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

  18. Simulations of octupole compensation of head-tail instability at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Meiqin Xiao; Tanaji Sen; Frank Schmidts

    2003-05-28

    The proton lifetime in the Tevatron depends sensitively on chromaticities. Too low chromaticities can make the beam unstable due to the weak head-tail instability. One way to compensate this effect is to introduce octupoles to create a larger amplitude dependent betatron tune spread. However, the use of octupoles will also introduce additional side effects such as second order chromaticity, differential tune shifts and chromaticities on both proton and anti-proton helices. The non-linear effects may also reduce the dynamic aperture. There are 67 octupoles in 4 different circuits in the Tevatron which may be used for this purpose. We report on a simulation study to find the best combinations of polarities and strengths of the octupoles.

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

    International Nuclear Information System (INIS)

    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.

  20. Prediction of Thermal and Elastic Properties of Honeycomb Sandwich Plate for Analysis of Thermal Deformation

    International Nuclear Information System (INIS)

    Thermal problems that are directly related to the lifetime of an electronic device are becoming increasingly important owing to the miniaturization of electronic devices. To solve thermal problems, it is essential to study thermal stability through thermal diffusion and insulation. A honeycomb sandwich plate has anisotropic thermal conductivity. To analyze the thermal deformation and temperature distribution of a system that employs a honeycomb sandwich plate, the thermal and elastic properties need to be determined. In this study, the thermal and elastic properties of a honeycomb sandwich plate, such as thermal conductivity, coefficient of thermal expansion, elastic modulus, Poisson's ratio, and shear modulus, are predicted. The properties of a honeycomb sandwich plate vary according to the hexagon size, thickness, and material properties

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

    International Nuclear Information System (INIS)

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

  2. Structure and properties of Fe-36% Ni alloy after heavy shear deformation

    International Nuclear Information System (INIS)

    A study was made into the influence of large shear strain by pressing on structure, mechanical and thermal properties of the Fe-36% Ni invar. The first pressing pass (70% reduction) is shown to result in formation of strip structure. An increase of the number of passes with changing shear deformation direction for reverse one at every even pressing p[ass promotes strip structure transformation into fragmented one. Yield strength of the alloy increases from 300 to 650 N/mm2 after the first pass. After 12 passes at attains the value of 800 N/mm2 due to strain hardening. A linear thermal expansion coefficient varies nonmonotonously with deformation, and after 12 passes preserves a permissible value. 17 refs., 10 figs

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

    Energy Technology Data Exchange (ETDEWEB)

    Garner, H.; Post, R. S.

    1981-02-01

    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.

  4. Octupole instability induced by rotation in the nuclei 146,148Nd

    International Nuclear Information System (INIS)

    Levels in 146,148Nd have been populated in the 150Nd (?, ?'xn) reactions. Cascades of enhanced E1 transitions have been observed. B(E1)/B(E2) branching ratios, of the order of 10-6 fm-2 as well as the presence of low energy negative-parity bands indicate strong octupole effects. Shell correction type calculations suggest an explanation in terms of octupole correlations at medium spins. (orig.)

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

    OpenAIRE

    Hennig, A.; Spieker, M.(Institute for Nuclear Physics, University of Cologne, Zülpicher Straße 77, Cologne, D-50937, Germany); Werner, V.; Ahn, T; Anagnostatou, V.; Cooper, N.; Derya, V.; Elvers, M.; Endres, J.; Goddard, P.; Heinz, A.; Huges, R. O.; Ilie, G.; Mineva, M. N.; Petkov, P.

    2015-01-01

    Background: Excitations with mixed proton-neutron symmetry have been previously observed in the $N=52$ isotones. Besides the well established quadrupole mixed-symmetry states (MSS), octupole and hexadecapole MSS have been recently proposed for the nuclei $^{92}$Zr and $^{94}$Mo. Purpose: The heaviest stable $N=52$ isotone $^{96}$Ru was investigated to study the evolution of octupole and hexadecapole MSS with increasing proton number. Methods: Two inelastic proton-scattering experiments on $^{...

  6. Location of the low-energy isoscalar octupole resonance in 58Ni

    International Nuclear Information System (INIS)

    The levels of 58Ni have been studied by inelastic proton scattering at E/sub p/ = 65 MeV. The fine structure of the low-energy octupole resonance in 58Ni has been observed. An octupole strength of ?18% of the energy-weighted sum rule is obtained for the fragmented 3- states at E/sub x/<12 MeV. This sum rule strength is consistent with a simple shell model estimate

  7. Theoretical study on effect of radial and axial deformation on electron transport properties in a semiconducting Si–C nanotube

    Indian Academy of Sciences (India)

    Sudhanshu Choudhary; S Qureshi

    2012-10-01

    We investigate electron transport properties 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 results suggest significant reduction in threshold voltage in the case of both radially compressed and axially elongated (8, 0) SiCNTs, a large difference in current–voltage characteristics was observed. Analysis of frontier molecular orbitals (FMO) and transmission spectrum show bandgap reduction in deformed nanotubes. Deformation introduces electronic states near the Fermi level, enhancing the conduction properties of (8, 0) SiCNT. The FMOs and the orbitals corresponding to peaks in () around Fermi level obviously has some major contributions from the deformed site. However, localization of the electronic state near the Fermi level is weak in (8, 0) SiCNT, possibly because of its large bandgap.

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

    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 S III. Two approximations have been used for the treatment of pairing correlations: the constant (versus deformation) gap method and the constant (versus deformation) pairing matrix element method. A good agreement with experimental data is obtained for ground state deformation properties except for the exact location of the prolate-oblate transition as a function of the neutron number. For one nucleus 184Hg, the pairing matrix elements have been calculated from the Gogny interaction D1, in order to study their single particle state- and deformation-dependence. From these results, the validity of the two approximations used for pairing correlations, is discussed

  9. 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

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

    Directory of Open Access Journals (Sweden)

    Daniel Fruchart

    2012-08-01

    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.

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

    DEFF Research Database (Denmark)

    KrogsbØll, Anette; Hededal, Ole

    2012-01-01

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

  12. Deformation, fracture, and mechanical properties of low-temperature-tempered martensite in SAE 43xx steels

    Energy Technology Data Exchange (ETDEWEB)

    Saeglitz, M. [Deutsche Bahn AG, Brandenburg-Kirchmoeser (Germany); Krauss, G. [Colorado School of Mines, Golden, CO (United States). Dept. of Metallurgical and Materials Engineering

    1997-02-01

    Uniaxial tensile tests were performed on 4330, 4340, and 4350 steels in the as-quenched (AQ) condition and after quenching and tempering at 150 C, 175 C, and 200 C for times of 10 minutes, 1 hour, and 10 hours, respectively. Strength parameters decreased and ductility parameters increased continuously with increasing tempering. Mechanical properties are presented as a function of tempering conditions and steel carbon content, and hardness and ultimate strength changes are given as a function of Hollomon-Jaffe tempering parameters. All tempered specimens, except for some lightly tempered 4350 specimens, deformed plastically through necking instability and failed by ductile fracture. The stresses required for the ductile fracture, estimated from an analysis of the interfacial stresses at particles in the neck at fracture, showed no systematic variation with carbon content of tempering conditions despite significant variations in deformation and strain hardening. The AQ specimens of the 4340 and 4350 steels, and some of the lightly tempered 4350 steels, failed by brittle mechanisms. The deformation and fracture of the low-temperature-tempered 43xx steels are discussed in terms of the changes in fine structure, namely, the formation of transition carbides and a rearranged dislocation substructure that evolve from an AQ martensitic substructure consisting of dislocations with and without carbon atom segregation.

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

    DEFF Research Database (Denmark)

    Huang, Xiaoxu; Kamikawa, Naoya; Hansen, Niels

    The effect of post-process deformation on the mechanical properties of nanostructured aluminum (99.2% purity) has been investigated by cold rolling of samples which have been processed by accumulative roll bonding (ARB) to a strain of epsilon(vM) = 4.8. Samples have been cold rolled to 10, 15, and...... 50% reductions and ultimate tensile strength (UTS), yield stress and elongation have been determined by tensile testing at room temperature. The mechanical testing shows that cold rolling to low strains (10% and 15%) leads to softening and increase in elongation compared to the as-processed ARB...

  14. Enhanced mechanical properties in a Zr-based metallic glass caused by deformation-induced nanocrystallization

    International Nuclear Information System (INIS)

    Bulk metallic glass with composition Zr62Cu18Ni10Al10 exhibits high yield stress, large elasticity and large plasticity when compressed. During nanoindentation, strain hardening is observed until the maximum applied load reaches 100 mN; for higher maximum loads the typical softening found in metallic glasses is evidenced. Transmission electron microscopy observation of the nanoindented and compressed samples reveals the occurrence of deformation-induced nanocrystallization, which is likely to be related to the mechanical properties observed in this alloy.

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

    Energy Technology Data Exchange (ETDEWEB)

    Langdon, T. G.

    2008-07-01

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

  16. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.

  18. Effects of deformation on the electronic properties of B–C–N nanotubes

    International Nuclear Information System (INIS)

    We apply first-principles methods, using density functional theory, to investigate the effects of flattening deformation on the electronic properties of BC2N and C-doped BNNTs. Four different types of BC2N 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 BC2N and C-doped BNNTs. Four different types of BC2N 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: ? We investigated electronic properties of flattened BC2N nanotubes. ? The electronic states depend strongly on compression. ? It is studied flattened BN nanotubes doped with a carbon atom. ? The flattened C-doped structures, presents a significant reduction of the gap.

  19. Influence of intense plastic deformation on structure and magnetic properties of Pr-Fe-B-Cu system alloy

    International Nuclear Information System (INIS)

    A study is made into the influence of plastic deformation by torsion under hydrostatic pressure on microstructure phase composition and magnetic hysteresis in cast alloy Pr20Fe73.5B5Cu1.5. It is shown that heavy deformation results in essential refinement if basic Pr2Fe14B phase and subsequent formation of nonequilibrium and amorphous phases. The structural changes are the reasons for the external dependence of coercive force Hc on deformation degree. The annealing of heavily deformed specimens is accompanied by a sharp decrease of coercive force up to values exceeding 1600 kA/m. It is concluded that heavy deformation along with rapid quenching is a promising method to improve crystal structure and magnetic properties of R2Fe14B intermetallic alloys

  20. Ion-cyclotron-resonance heating in the Wisconsin Levitated Octupole

    International Nuclear Information System (INIS)

    Ion-cyclotron-resonance heating has been investigated, both experimentally and theoretically, on the Wisconsin Levitated Octupole. Heating of both ions and electrons has been observed. Typically, a two-component ion energy distribution is produced (300 eV and 50 eV) with 500 kW of rf power coupled into a 5 x 1012 cm-3 plasma. Power is coupled to the plasma with an antenna that also serves as the inductor of an oscillator tank circuit. The oscillator is tunable from 1 to 3 MHz and can be applied for periods up to 10 msec. The experiments were performed with hydrogen, gun-injected plasmas. Most of the theortical work presented deals with a calculation that predicts the plasma loading. A slab model is used, and the questions of accessibility, polarization, and damping of the radio-frequency electromagnetic fields are addressed. It is found that cold-plasma theory cannot account for the heating and, therefore, hot-plasma theory is invoked to explain the results. The loading measurements and theoretical predictions are found to be in reasonable agreement

  1. Octupole Focusing Relativistic Self-Magnetometer Electric Storage Ring "Bottle"

    CERN Document Server

    Talman, Richard

    2015-01-01

    A method proposed for measuring the electric dipole moment (EDM) of a charged fundamental particle such as the proton, is to measure the spin precession caused by a radial electric bend field $E_r$, acting on the EDMs of frozen spin polarized protons circulating in an all-electric storage ring. The dominant systematic error limiting such a measurement comes from spurious spin precession caused by unintentional and unknown average radial magnetic field $B_r$ acting on the (vastly larger) magnetic dipole moments (MDM) of the protons. Along with taking extreme magnetic shielding measures, the best protection against this systematic error is to use the storage ring itself, as a "self-magnetometer"; the exact magnetic field average $\\langle B_r\\rangle$ that produces systematic EDM error, is nulled to exquisite precision by orbit position control. By using octupole rather than quadrupole focusing the restoring force can be vanishingly small for small amplitude vertical betatron-like motion yet strong enough at larg...

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

    International Nuclear Information System (INIS)

    Explicit integral expressions are given for the fifth-order geometrical aberration coefficients in rectilinear magnetic quadrupole-octupole systems used for the transport of nonrelativistic charged particle beams. The numerical values of the fifth-order geometrical aberration coefficients for a rare earth cobalt (REC) quadrupole doublet are given as an example. In the calculations presented here, the author has used Mathematica on a NeXT computer to generate the results. Mathematica provides options to write expressions in a form suitable for input to TEX, or in formats that can be inserted into C or FORTRAN programs. The expressions in Appendix A and C are generated and put into TEX form by Mathematica. The organization of the paper is as follows. The basic equations used here are given in Sec. II while the paraxial and third-order solutions are given in Sec. III and IV respectively. Explicit integral expressions for the fifth-order geometrical aberration coefficients are given in Sec. V. In Sec. VI, numerical values for the third- and fifth-order geometrical aberration coefficients of a REC quad doublet are given. Finally, some concluding remarks are given in Sec. VII

  3. Observation of the Nuclear Magnetic Octupole Moment of 137Ba+

    Science.gov (United States)

    Hoffman, Matthew

    Single trapped ions are ideal systems in which to test atomic physics at high precision, which can in turn be used for searches for violations of fundamental symmetries and physics beyond the standard model, in addition to quantum computation and a number of other applications. The ion is confined in ultra-high vacuum, is laser cooled to mK temperatures, and kept well isolated from the environment which allows these experimental efforts. In this thesis, a few diagnostic techniques will be discussed, covering a method to measure the linewidth of a narrowband laser in the presence of magnetic field noise, as well as a procedure to measure the ion's temperature using such a narrowband laser. This work has led to two precision experiments to measure atomic structure in 138Ba+, and 137Ba+ discussed here. First, employing laser and radio frequency spectroscopy techniques in 138Ba+, we measured the Lande- gJ factor of the 5D5/2 level at the part-per-million level, the highest precision to date. Later, the development of apparatus to efficiently trap and laser cool 137Ba+ has enabled a measurement of the hyperfine splittings of the 5D3/2 manifold, culminating in the observation of the nuclear magnetic octupole moment of 137Ba+.

  4. Deformed bialgebra of diffeomorphisms

    International Nuclear Information System (INIS)

    We review some of the properties of deformed spaces. Especially, the concept of derivatives is analyzed in detail. As a new result we present the deformed bialgebra of diffeomorphisms and among them the special example of deformed Lorentz transformations. (author)

  5. Interpretation of fluid inclusions in quartz deformed by weak ductile shearing: Reconstruction of differential stress magnitudes and pre-deformation fluid properties

    Science.gov (United States)

    Diamond, Larryn W.; Tarantola, Alexandre

    2015-05-01

    A well developed theoretical framework is available in which paleofluid properties, such as chemical composition and density, can be reconstructed from fluid inclusions in minerals that have undergone no ductile deformation. The present study extends this framework to encompass fluid inclusions hosted by quartz that has undergone weak ductile deformation following fluid entrapment. Recent experiments have shown that such deformation causes inclusions to become dismembered into clusters of irregularly shaped relict inclusions surrounded by planar arrays of tiny, new-formed (neonate) inclusions. Comparison of the experimental samples with a naturally sheared quartz vein from Grimsel Pass, Aar Massif, Central Alps, Switzerland, reveals striking similarities. This strong concordance justifies applying the experimentally derived rules of fluid inclusion behaviour to nature. Thus, planar arrays of dismembered inclusions defining cleavage planes in quartz may be taken as diagnostic of small amounts of intracrystalline strain. Deformed inclusions preserve their pre-deformation concentration ratios of gases to electrolytes, but their H2O contents typically have changed. Morphologically intact inclusions, in contrast, preserve the pre-deformation composition and density of their originally trapped fluid. The orientation of the maximum principal compressive stress (?1) at the time of shear deformation can be derived from the pole to the cleavage plane within which the dismembered inclusions are aligned. Finally, the density of neonate inclusions is commensurate with the pressure value of ?1 at the temperature and time of deformation. This last rule offers a means to estimate magnitudes of shear stresses from fluid inclusion studies. Application of this new paleopiezometer approach to the Grimsel vein yields a differential stress (?1-?3) of ˜ 300 MPa at 390 ± 30 °C during late Miocene NNW-SSE orogenic shortening and regional uplift of the Aar Massif. This differential stress resulted in strain-hardening of the quartz at very low total strain (< 5%) while nearby shear zones were accommodating significant displacements. Further implementation of these experimentally derived rules should provide new insight into processes of fluid-rock interaction in the ductile regime within the Earth's crust.

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

    International Nuclear Information System (INIS)

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

  7. 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.

  8. Deformation properties between fluid and periodic circular obstacles in polydimethylsiloxane microchannels: Experimental and numerical investigations under various conditions

    OpenAIRE

    Kang, ChanKyu; Overfelt, Ruel A.; Roh, Changhyun

    2013-01-01

    Understanding the mechanical properties of optically transparent polydimethylsiloxane (PDMS) microchannels was essential to the design of polymer-based microdevices. In this experiment, PDMS microchannels were filled with a 100??M solution of rhodamine 6G dye at very low Reynolds numbers (?10?3). The deformation of PDMS microchannels created by pressure-driven flow was investigated by fluorescence microscopy and quantified the deformation by the linear relationship between dye layer thickness...

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

    OpenAIRE

    Middleton, C.

    2012-01-01

    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 ...

  10. Octupole correlations in positive-parity states of rare-earth and actinide nuclei

    Directory of Open Access Journals (Sweden)

    Spieker M.

    2015-01-01

    Full Text Available In this contribution, further evidence of the importance of multiphonon-octupole excitations to describe experimental data in the rare earths and actinides will be presented. First, new results of a (p, t experiment at the Q3D magnetic spectrograph in Munich will be discussed, which was performed to selectively excite J? = 0+ states in 240Pu. spdf interacting boson model (IBM calculations suggest that the previously proposed double-octupole phonon nature of the J? = 0+2 state is not in conflict with its strong (p, t population. Second, the framework of the IBM has been adopted for the description of experimental observables related to octupole excitations in the rare earths. Here, the IBM is able to describe the signature splitting for positiveand negative-parity states when multi-dipole and multi-octupole bosons are included. The present study might support the idea of octupole-phonon condensation at intermediate spin (J? = 10+ leading to the change in yrast structure observed in 146Nd.

  11. Optomechanical properties of cancer cells revealed by light-induced deformation and quantitative phase microscopy

    Science.gov (United States)

    Kastl, Lena; Budde, Björn; Isbach, Michael; Rommel, Christina; Kemper, Björn; Schnekenburger, Jürgen

    2015-05-01

    There is a growing interest in cell biology and clinical diagnostics in label-free, optical techniques as the interaction with the sample is minimized and substances like dyes or fixatives do not affect the investigated cells. Such techniques include digital holographic microscopy (DHM) and the optical stretching by fiber optical two beam traps. DHM enables quantitative phase contrast imaging and thereby the determination of the cellular refractive index, dry mass and the volume, whereas optical cell stretching reveals the deformability of cells. Since optical stretching strongly depends on the optical properties and the shape of the investigated material we combined the usage of fiber optical stretching and DHM for the characterization of pancreatic tumor cells. The risk of tumors is their potential to metastasize, spread through the bloodstream and build distal tumors/metastases. The grade of dedifferentiation in which the cells lose their cell type specific properties is a measure for this metastatic potential. The less differentiated the cells are, the higher is their risk to metastasize. Our results demonstrate that pancreatic tumor cells, which are from the same tumor but vary in their grade of differentiation, show significant differences in their deformability. The retrieved data show that differentiated cells have a higher stiffness than less differentiated cells of the same tumor. Even cells that differ only in the expression of a single tumor suppressor gene which is responsible for cell-cell adhesions can be distinguished by their mechanical properties. Additionally, results from DHM measurements yield that the refractive index shows only few variations, indicating that it does not significantly influence optical cell stretching. The obtained results show a promising new approach for the phenotyping of different cell types, especially in tumor cell characterization and cancer diagnostics.

  12. Plasma Confinement in a Toroidal Octupole Magnetic Field

    International Nuclear Information System (INIS)

    The confinement of low-density (n = 109 cm-3) collisionless plasmas with Ti ? 40 eV, Te ? 10 eV produced by gun injection or with Te ? 1 eV. Ti -3of the Bohm diffusion coefficient which was not large enough to produce the observed radial loss. Studies were also made to determine the importance of low-frequency fluctuations or convective cells which may have been produced by injection, magnetic field perturbations or azimuthal density variations. The addition of a toroidal magnetic field decreased the lifetime slightly and generated large-scale convective cells in the shearless layer near the plasma surface. Currents parallel to the magnetic field have been observed which must be considered in determining the cause of increased fluctuation with the increase of the toroidal field. The mechanical supports were also guarded with magnetic dipoles in the manner proposed by Lehnert. The plasma flux to one of the supports was reduced for the hot ion plasma by an order of magnitude when there was one ion gyroradius between the mechanical support and the guard field separatrix. However, the plasma flux along the guard field separatrix increased to the value of the original support flux and there was a negligible ( ? 20%) improvement of the lifetime. An inductively excited, magnetically force-free octupole is being assembled with transiently withdrawn supports to eliminate the plasma loss to hoop supports. The device will provide at least 10 msec of experimental time during which only 5% of the magnetic flux diffuses into the internal hoops. 100 eV protons will have 15 gyroradii on each side of the separatrix. (author)

  13. Effect of mechanical deformation on the electrical properties of organic single crystals

    Science.gov (United States)

    Reyes-Martinez, Marcos; Crosby, Alfred; Briseno, Alejandro

    2014-03-01

    Despite efforts in the flexible electronics field, relatively little research quantified the effects of mechanical strain on the electrical properties of organic single crystals (OSCs) and their device performance in deformed geometries. Single crystals of organic semiconductors are ideal systems for the elucidation of these effects without having to account for imperfections, grain boundaries and other defects. The aim of this presentation is to bring new understanding of the effects of mechanical strain in charge transport phenomena on OSCs. First, the existence of a piezoresistive effect in rubrene crystals is demonstrated and experimentally quantified by the application of in-plane strain along its [010] axis. A piezoresistive coefficient approximately 50 is determined. Second, the effect of local mechanical deformation on the conductive channel is investigated in rubrene single-crystal field-effect transistors. A wrinkling instability is used as a technique to apply local strains of different magnitudes to the conducting channel of field-effect transistors. All devices maintain excellent transistor behavior, and small, reversible changes in performance are observed during wrinkling. This work provides useful knowledge for the effective application of organic semiconductors in strain intensive applications such as pressure sensors, electronic skins and strained-channel organic transistors.

  14. Transient deformation properties of Zircaloy for LOCA simulation. Final report, Volume 2

    Energy Technology Data Exchange (ETDEWEB)

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

    1978-03-01

    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 600/sup 0/F (589/sup 0/K) to 2200/sup 0/F (1477/sup 0/K), with the emphasis on the 800/sup 0/F (700/sup 0/K) to 2000/sup 0/F (1366/sup 0/K) temperature levels in low pressure air (6.5 x 10/sup -5/ atm) and in a 1 atm mixture of 20 percent oxygen, 80 percent argon. Stress levels of 60 to 95 percent 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 percent 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 to 120 seconds, computer codes and ramp test data.

  15. Transient deformation properties of Zircaloy for LOCA simulation. Volume 2. Final report

    Energy Technology Data Exchange (ETDEWEB)

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

    1978-03-01

    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 600/sup 0/F (589 K) to 2200/sup 0/F (1477 K), with the emphasis on the 800/sup 0/F (700 K) to 2000/sup 0/F (1366 K) temperature levels in low pressure air (6.5 x 10/sup -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 to 120 seconds, computer codes and ramp test data.

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

    Science.gov (United States)

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

    2010-05-01

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

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

    CERN Document Server

    Kubo, K; Kubo, Katsunori; Kuramoto, Yoshio

    2003-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-09-20

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

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

    International Nuclear Information System (INIS)

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

  20. Temperature dependence of deformation vs. strength properties of radiation-crosslinked polyethylene

    International Nuclear Information System (INIS)

    The authors have studied the deformation vs. strength properties of radiation-crosslinked low-density polyethylene irradiated by ? irradiation up to doses from 5.0 sm-bullet 104 to 1.0 sm-bullet 106 Gy. The authors present the elongation diagrams taken at temperatures below and above the melting point of the polymer. The authors have obtained the dependences of the breaking stress and the pre-break elongation of the polymer on the irradiation doses and the testing temperature. Based on the kinetic lifetime equation, The authors calculated the values of the activation energy for mechanical fracture and the structure-sensitive coefficient ?. The authors show that in the crystalline state the strength of radiation-crosslinked polyethylene is determined by the chemical interactions along the chain of polymer macromolecules; and in molten polyethylene, by the crosslinks between the macromolecules. 8 refs., 4 figs., 1 tab

  1. Formation of structure and properties of commercial titanium with nanocrystalline structure after deformation and subsequent heating

    International Nuclear Information System (INIS)

    The influence of shear deformation degree on grain size and mechanical properties of titanium VT1-0 alloy was investigated. it is revealed that the structure with mean grain size of 100 nm can be produced by way of intense torsion. As this takes place some areas with grain size of 20-30 nm can exist. Postdeformation heating results in two main stages of structural transformations. The low temperature transformation (below 250 deg C) proceeds with a fairly high rate and involves stress and dislocation redistribution. Transformations above 300 deg C proceed by recrystallization mechanism. Nanocrystalline commercial titanium exhibits the best combination of strength and plasticity being annealed at 250 deg C

  2. The Properties of Bulk Ultrafine-Grained Metals Processed Through the Application of Severe Plastic Deformation

    Science.gov (United States)

    Langdon, Terence G.

    Processing through the application of severe plastic deformation (SPD) provides a very attractive tool for the production of bulk ultrafine-grained materials. These materials typically have grain sizes in the submicrometer or nanometer ranges and they exhibit high strength at ambient temperature and, if the ultrafine grains are reasonably stable at elevated temperatures, they have a potential for use in superplastic forming operations. Several procedures are now available for applying SPD to metal samples but the most promising are Equal-Channel Angular Pressing (ECAP) and High-Pressure Torsion (HPT). This paper examines the basic principles of ECAP and HPT and describes some of the properties that may be achieved using these processing techniques.

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

    OpenAIRE

    Chbihi, Abdelahad; Sauvage, Xavier; Genevois, Cécile; Blavette, Didier; Gunderov, Dmitry; Popov, Alexander

    2012-01-01

    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...

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-05-28

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

  6. 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.)

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

    Science.gov (United States)

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

    2011-12-01

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

  8. The influence of hydrogen, deformation geometry, and grain size on the rheological properties of olivine at upper mantle conditions

    Science.gov (United States)

    Tielke, Jacob A.

    Many important geophysical processes, including mantle convection and the associated movement of Earth's tectonic plates, are strongly dependent upon the rheological properties of Earth's upper mantle. Olivine is the most abundant mineral in the upper mantle and therefore largely controls the mechanical behavior of this region of Earth's interior. Many experimental investigations have been carried out to study the rheological properties of olivine single crystals, synthetically produced aggregates, and naturally occurring mantle rocks at asthenospheric temperatures. In contrast, relatively few studies have focused on measuring the rheological properties of olivine deforming at lithospheric temperatures. Furthermore, there are several unanswered questions about the microphysical processes that control deformation of olivine at upper mantle conditions. One outstanding question in the field of rock and mineral physics is Do different microphysical processes control the rate of deformation of olivine at asthenospheric compared to lithospheric mantle conditions? To address this question we carried out direct shear experiments on olivine single crystals at temperatures that span the transition from lithospheric to asthenospheric mantle conditions. The results of these experiments, which are presented in Chapter 2, demonstrate that the dependence of strain rate upon stress transitions from a power-law relationship at high temperatures to an exponential dependence at lower temperatures. This transition in rheological behavior is consistent with deformation that is controlled by the climb of dislocations at high-temperature conditions and deformation that is controlled by the glide of dislocations at low-temperature conditions. Furthermore, the direct shear geometry allows for isolation of the (001)[100] and (100)[001] dislocation slip systems, which cannot be individually activated in triaxial compression. At high-temperature conditions, crystals oriented for shear on the (001)[100] slip system are observed to be weaker than crystals oriented for shear on the (100)[001] slip system. At low-temperature conditions the opposite relationship is observed: crystals oriented for shear on the (100)[001] slip system are weakest. Another important outstanding question is Do the mechanisms of hydrolytic weakening in olivine differ at asthenospheric compared to lithospheric mantle conditions? In Chapter 3 we report the results of experiments carried out on olivine single crystals under hydrous conditions at both asthenospheric and lithospheric temperatures. For crystals deformed at high-temperatures and under hydrous conditions, the dependence of strain rate on stress follows a power-law relationship with a stress exponent (n) of ~2.5, consistent with deformation that is rate limited by diffusion of silicon through the olivine lattice. In contrast, crystals deformed at high-temperatures and under anhydrous conditions yield n values of ~3.5, consistent with deformation that is rate limited by diffusion of silicon through the cores of dislocations. At low temperature conditions, the strain rate of both hydrous and anhydrous crystals are equally well described by the same exponential dependence of stress. These observations demonstrate significant hydrolytic weakening occurs at asthenospheric temperatures, but hydrolytic weakening cannot be resolved at lithospheric temperatures for our experimental conditions. Lastly, we address a question about polycrystalline deformation: What deformation mechanism is responsible for grain-size sensitive (GSS) power-law creep of olivine aggregates? In Chapter 4 we compare strain rates measured during deformation experiments on olivine aggregates to strain rates calculated from a micromechanical model of intragranular slip. The micromechanical model uses the measured stress from deformation experiments and grain orientations determined from post-deformation electron backscatter diffraction measurements to approximate the contribution of dislocation creep to the strain rate. Olivine aggregates deform up to a f

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

    Energy Technology Data Exchange (ETDEWEB)

    Yu Xiaohui, E-mail: xiaohui@lanl.gov [Department of Physics, University of Science and Technology of China, Hefei 230026 (China); LANSCE Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); National Lab for Condensed Matter Physics, Institute of Physics, CAS, Beijing 100080 (China); Zhang Jianzhong [LANSCE Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Wang Liping [Mineral Physics Institute, State University of New York, Stony Brook, NY 11794 (United States); Ding Zejun [Department of Physics, University of Science and Technology of China, Hefei 230026 (China); Jin Changqing [National Lab for Condensed Matter Physics, Institute of Physics, CAS, Beijing 100080 (China); Zhao Yusheng, E-mail: yzhao@lanl.gov [LANSCE Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2011-05-15

    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 10{sup 16} m{sup -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.

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

    International Nuclear Information System (INIS)

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

  11. Investigation of structure and properties of Co-Cr-Mo alloy in as-cast and hot-deformed states

    International Nuclear Information System (INIS)

    The microstructure, phase composition and mechanical properties of as-cast and hot-deformed samples of Co-Cr-Mo alloys were investigated using the methods of metallographic and X-ray diffraction analyses during furnace and rapid heating. (authors).

  12. The influence of severe plastic deformation on the structure and magnetic properties of a Pr-Fe-B-Cu alloy

    International Nuclear Information System (INIS)

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

  13. Interpretation of fluid inclusions in quartz deformed by weak ductile shearing: reconstruction of differential stress magnitudes and pre-deformation fluid properties

    Science.gov (United States)

    Tarantola, Alexandre; Diamond, Larryn W.

    2015-04-01

    A well developed theoretical framework is available in which paleofluid properties, such as chemical composition and density, can be reconstructed from fluid inclusions in minerals that have undergone no ductile deformation. Fluid inclusions are known to reequilibrate during strong post-entrapment changes in hydrostatic confining pressure (e.g. Sterner and Bodnar 1989). The present study extends this framework to encompass fluid inclusions hosted by quartz that has undergone weak ductile deformation following fluid entrapment. Recent piston-cylinder experiments (Griggs apparatus) made on single quartz crystals have shown that such deformation causes inclusions to become dismembered into clusters of irregularly shaped relict inclusions surrounded by planar arrays of tiny, new-formed (neonate) inclusions (Diamond et al. 2010; Tarantola et al. 2010, 2012). Comparison of the experimental samples with a naturally sheared quartz vein from Grimsel Pass, Central Alps, Switzerland, reveals striking similarities. This strong concordance justifies applying the experimentally derived rules of fluid inclusion behaviour to nature. Thus, planar arrays of dismembered inclusions defining cleavage planes in quartz may be taken as diagnostic of small amounts of intracrystalline strain. Deformed inclusions preserve their pre-deformation concentration ratios of gases to electrolytes, but their H2O contents typically have changed. Morphologically intact inclusions, in contrast, preserve the pre-deformation composition and density of their originally trapped fluid. The orientation of the maximum principal compressive stress (?1) at the time of shear deformation can be derived from the pole to the cleavage plane within which the dismembered inclusions are aligned. Finally, the density of neonate inclusions is commensurate with the pressure value of ?1 at the temperature and time of deformation. This last rule offers a means to estimate magnitudes of shear stresses from fluid inclusion studies. Application of this new paleopiezometer approach to the Grimsel vein yields a differential stress (?1 - ?3) of ~300 MPa at 390 ± 30 °C during late Miocene NNW-SSE orogenic shortening and regional uplift of the Aar Massif. This differential stress resulted in strain-hardening of the quartz at very low total strain (<5%) while nearby shear zones were accommodating significant displacements. Further implementation of these experimentally derived rules should provide new insight into processes of fluid-rock interaction in the ductile regime within the Earth's crust. Diamond, L.W., Tarantola, A., Stünitz, H., 2010. Modification of fluid inclusions in quartz by deviatoric stress II: Experimentally induced changes in inclusion volume and composition. Contrib. Mineral. Petrol. 160, 845-864. Sterner, S.M. and Bodnar, R.J., 1989. Synthetic fluid inclusions-VII. Re-equilibration of fluid inclusions in quartz during laboratory-simulated metamorphic burial and uplift. J. Metamorph. Geol., 7, 243¬-260. Tarantola, A., Diamond, L.W., Stünitz, H., 2010. Modification of fluid inclusions in quartz by deviatoric stress. I: Experimentally induced changes in inclusion shapes and microstructures. Contrib. Mineral. Petrol. 160, 825-843. Tarantola, A., Diamond, L.W., Stünitz, H., Thust, A., Pec, M., 2012. Modification of fluid inclusions in quartz by deviatoric stress. III: Influence of principal stresses on inclusion density and orientation. Contrib. Mineral. Petrol. 164, 527-550.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-09-06

    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.

  15. Microstructure and properties of 700 MPa grade HSLA steel during high temperature deformation

    International Nuclear Information System (INIS)

    Highlights: • Hot deformation behavior of 700 MPa HSLA steel above 1200 °C in was detailed studied. • Uniform and granular bainite is formed when the deformation amount is 40%. • Deformation resistance value under steady-equilibrium state is about 56 MPa. - Abstract: A high temperature deformation experiment was conducted on a high strength low alloy (HSLA) steel Q690 using Thermecmastor-Z thermal/physical simulator. During the experiment, the specimens were heated from room temperature to 1200 °C with the heating rate of 10 °C/s and 50 °C/s, respectively. The deformation temperature was 1200 °C and the deformation amounts were 0%, 10% and 40%, respectively. The microstructures, stress–strain diagram and hardness were obtained. The results revealed that the microstructure transformation of deformed austenite was quite different from that of the normal situation. With the increasing of deformation amount, more lath-shaped microstructure and less granulous microstructure were observed. The compressive deformation effectively prevented the precipitation of carbides. Larger deformation amount or lower heating rate was conducive to the atomic diffusion, which led to the microstructure uniformity and hardness decreasing. The maximum stress was 68.4 MPa and the steady stress was about 56 MPa

  16. The study of magnetic properties, coercivity mechanism and bending strength of hot-deformed RE-Fe-B magnets

    International Nuclear Information System (INIS)

    The effect on mechanical properties and magnetic properties of hot-deformed magnets with different rare earth (RE) content has been investigated. The results show that the optimal comprehensive magnetic properties are obtained at 13.09 at% RE. The bending strength parallel to c-axis orientation increases with the increasing of RE content, while that perpendicular to c-axis orientation exhibits decrease. Moreover, the micro magnetic structure was observed and the coercivity mechanism of the hot-deformed magnet sample was discussed. - Highlights: • The optimal comprehensive magnetic properties are obtained at 13.09 at% RE. • The bending strength with different rare earth content is determined. • Domain wall moved irreversibly when the external field gets close to the coercivity. • Inhomogeneous domain wall pinning should be the dominant coercivity mechanism

  17. Convective cells and their relationship to vortex diffusion in the Wisconsin Levitated Octupole

    International Nuclear Information System (INIS)

    The purpose of this thesis is two-fold: first, to present floating potential structure for different plasmas and operating parameters in the Wisconsin Levitated Octupole. Second, to show how the observed potential structure can be used, within the framework of vortex diffusion, to account for enhanced diffusion in the appropriate parameter regimes

  18. 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

  19. Single-beam measurements of LHC instability threshold in terms of octupole current

    CERN Document Server

    Mounet, N; Buffat, X; Burov, A; Hemelsoet, G; Metral, E; Papotti, G; Pieloni, T; Pojer, M; Salvant, B; Trad, G

    2012-01-01

    This note summarizes two machine development (MD) studies aimed at determining the octupole current needed in the LHC in order to stabilize all headtail instabilities at 4TeV/c, before and after the squeeze, with tight collimator settings, and when a single beam (beam 2) at maximum intensity (1380 bunches, 2.1 1014 protons) is present in the machine. The MDs followed the normal physics operation procedure, at the notable exception that a single beam was used, the other beam containing only one non-colliding nominal bunch. Octupole current (with negative polarity in the focusing octupoles and the opposite in the defocusing ones) was decreased by small steps until the instability threshold was reached. This was performed in two distinct MDs, one before the squeeze and the other after it, testing also several chromaticity values and the effect of the transverse damper in the latter case. Octupole thresholds are shown in each case studied, as well as the rise times of the instabilities observed.

  20. Octupole Resonance in the AGS at High Intensity: A SIMBAD study

    International Nuclear Information System (INIS)

    We studied the Octupole (Montague) resonance in the AGS, in its high intensity mode, by tracking with the PIC code SIMBAD. We calculated, turn-by-turn, the betatron tune footprint from the eigenvalues of the one-turn matrix. We show that one should exercise particular caution when the betatron tunes are close together, since the matrix gives ambiguous results at the resonance

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

    Czech Academy of Sciences Publication Activity Database

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

    2012-01-01

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

  2. Deformed configurations, band structures and spectroscopic properties of $N = 50$ Ge and Se nuclei

    Indian Academy of Sciences (India)

    S K Ghorui; C R Praharaj

    2014-04-01

    The deformed configurations and rotational band structures in $N=50$ Ge and Se nuclei are studied by deformed Hartree–Fock with quadrupole constraint and angular momentum projection. Apart from the `almost’ spherical HF solution, a well-deformed configuration occurs at low excitation. A deformed well-mixed $\\Omega = 1/2^+$ neutron orbit comes down in energy (from the shell above $N = 50$) to break the $N = 50$ spherical shell closure. A = 7? isomer is predicted in 84Se at fairly low excitation energy. At higher excitation energies (8 MeV), a deformed band with = 7/2+–1/2? (based on $h_{11/2}$) neutron 1p–1h excitation, for 82Ge and 84Se, is shown in our calculation. Our study gives insight into possible deformed structures at spherical shell closure.

  3. Effect of cold deformation on structure and properties of aluminium alloy 1441 sheets

    International Nuclear Information System (INIS)

    The influence of tensile deformation on the 1441 alloy (Al-Cu-Mg-Li-Zr) in four states: quenched; quenched, straightened and naturally aged; annealed; quenched, straightened and artificially aged one, has been studied. It has been ascertained that deformation after quenching results in a considerable growth of yield strength. Artificial aging makes an insignificant contribution to stregthening of deformed sheet. 2 refs.; 4 figs

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

    International Nuclear Information System (INIS)

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

  5. Effect of severe plastic deformation and subsequent annealing on the structure and properties of the Kh20N80 alloy

    International Nuclear Information System (INIS)

    The features of the coarse-grained structure transformation into the nanocrystalline one in the process of the intensive plastic deformation through torsion under the quasi-hydrostatic pressure of 6 GPa at the room temperature is considered on the Kh20N80 alloy. The effect of the intensive plastic deformation on the alloy structure and properties is studied through the methods of the electron microscopy, X-ray structural analysis and microhardness measurement. It is shown that the obtained nanocrystalline structure is the nonequilibrium one and it maintains the thermal stability up to heating temperature no exceeding 500 deg C

  6. Numerical simulation of rupture propagation with thermal pressurization based on measured hydraulic properties :Importance of deformation zone width

    Science.gov (United States)

    Noda, H.

    2004-12-01

    Thermal expansion and pressurization of pore water may effectively reduce frictional resistance during slip at high strain rate for faults with impermeable clayey material in shallow depth (parameter in this process because the distribution of excess pore pressure is roughly equal to the width of deformation zone for relatively impermeable faults and pore pressure at the center rises more rapidly for thinner cases. In this study, dynamic rupture propagation simulation with thermal pressurization based on measured hydraulic properties of active faults demonstrates the importance of width of deformation zone. In the case that hydraulic properties of Hanaore fault in Southwest Japan (relatively impermeable) is used, when 100m radius asperity is assumed in which initial shear stress is set as static frictional level (0.6) and dynamic frictional coefficient is assumed to be 0.4, rupture velocity is proved sensitive to the width of deformation zone when it is less than 20mm under condition of 3km depth. When deformation width is reduced to 5mm, rupture velocity in direction of mode 2 exceeds S-wave velocity. This study also shows the importance of hydraulic properties by comparing results of a relatively impermeable fault and a permeable fault at different depths.

  7. Effects of deformation on microstructure and mechanical properties of a Cu-Al-Ni shape memory alloy

    International Nuclear Information System (INIS)

    In Cu-11.92 wt.%Al-3.78 wt.%Ni shape memory alloy, the influence of deformation and thermal treatments on the microstructure and mechanical properties under the compression test were studied by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), and differential scanning calorimetry (DSC). Experiments show that the mechanical properties of the alloy can be enhanced by convenient heat treatments. The alloy exhibits good mechanical properties with high ultimate compression strength and ductility after annealing at high temperature. However, it exhibits brittle fracture and dramatic strain hardening, with linear stress-strain behavior after annealing at low temperature. The changes in the mechanical properties have been linked to the evolution of the degree of order, occurrence of precipitation, and variation of the grain size. From microstructural observations, it is seen that the ?1' (18R) and ?1' (2H) martensite phases coexist at different fractions in the undeformed and deformed states. Deformation induces the changes between the ?1' and ?1' martensites and deformation-induced martensites form at preferred orientations as mechanical twins. The ?1' martensite variants are twin-related with respect to the (1-bar 2-bar 8)18R mirror plane and a new orientation relationship for these twin variants is derived as (1-bar 2-bar 8)A-parallel (1-bar 2-bar 8)C: [4-bar 61] A-parallel [4-bar 61]C. Additionally, an increase in the amount of deformation causes martensite reorientation, de-twinning, and dislocation generation; also, the martensite plates are seen to have rearranged in the same orientation to be parallel with each other

  8. Effect of severe plastic deformation on the specific heat and magnetic properties of cold rolled Gd sheets

    Science.gov (United States)

    Taskaev, S.; Skokov, K.; Khovaylo, V.; Buchelnikov, V.; Pellenen, A.; Karpenkov, D.; Ulyanov, M.; Bataev, D.; Usenko, A.; Lyange, M.; Gutfleisch, O.

    2015-03-01

    We report on specific heat and magnetic properties of thin Gd sheets obtained by means of a cold rolling technique. At temperatures well below Curie temperature TC, the cold rolling has a minor impact on the specific heat Cp. However, a well defined ?-type anomaly of Cp seen in the vicinity of TC in a polycrystalline Gd sample is markedly suppressed in the severely deformed samples. Depression of the ? peak is due to a large decrease of magnetization that presumably originates in a local magnetic anisotropy induced by the severe plastic deformation. Results of calculation of magnetocaloric effect from the Cp and magnetization data indicate that the magnetocaloric effect gradually decreases as the degree of plastic deformation increases. This trend is further confirmed by the direct measurements of the adiabatic temperature change ?Tad.

  9. Properties of the Shapiro steps in the ac driven Frenkel-Kontorova model with deformable substrate potential.

    Science.gov (United States)

    Teki?, Jasmina; Hu, Bambi

    2010-03-01

    Properties of the dynamical-mode-locking phenomena are studied in the ac driven overdamped Frenkel-Kontorova model with deformable substrate potential. Appearance of very large subharmonic steps due to deformation of the substrate potential significantly influences the stability and existence of harmonic steps. Strong correlation among harmonic and subharmonic steps has been observed in which the larger the width of half-integer steps, the smaller that of harmonic steps. Amplitude dependence of harmonic steps significantly changes with the deformation of the potential where deviation from the well-known Bessel-like oscillations appears. Strong influence of the frequency of the ac driving force on the appearance and size of subharmonic steps has been observed. PMID:20365893

  10. Microstructural Analysis of Severe Plastic Deformed Twin Roll Cast AZ31 for the Optimization of Superplastic Properties

    Energy Technology Data Exchange (ETDEWEB)

    Young, John P.; Askari, Hesam A.; Heiden, Michael J.; Hovanski, Yuri; Field, David P.; Zbib, Hussein M.

    2013-07-08

    In recent years magnesium alloys have attracted significant attention as potential candidates to replace many of the heavier metals used in some automotive applications. However, the limited formability of magnesium and its alloys at room temperature has driven interest in the superplastic forming magnesium as an alternative shaping method. Severe plastic deformation techniques have become a well studied method of refining the grain size and modifying the microstructural characteristics of many magnesium alloys to achieve greater superplastic properties. In this study twin roll cast (TRC) AZ31 magnesium alloy was subjected to equal channel angular pressing (ECAP) and friction stir welding (FSW). The influence of these severe plastic deformation processes on the grain size, texture and grain boundary character distribution was investigated to identify the optimum severe plastic deformation process for the superplastic forming of AZ31.

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

    Science.gov (United States)

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

    2015-05-01

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

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

    Directory of Open Access Journals (Sweden)

    Anibal Andrade Mendes Filho

    2012-02-01

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

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

    Science.gov (United States)

    Rogl, Gerda; Grytsiv, Andriy; Bursik, Jiri; Horky, Jelena; Anbalagan, Ramakrishnan; Bauer, Ernst; Mallik, Ramesh Chandra; Rogl, Peter; Zehetbauer, Michael

    2015-02-01

    The best p-type skutterudites with ZT > 1.1 so far are didymium (DD) filled, Fe/Co substituted, Sb-based skutterudites. DD0.68Fe3CoSb12 was prepared using an annealing-reacting-melting-quenching technique followed by ball milling and hot pressing. After severe plastic deformation via high-pressure torsion (HPT), no phase changes but particular structural variations were achieved, leading to modified transport properties with higher ZT values. Although after measurement-induced heating some of the HPT induced defects were annealed out, a still attractive ZT-value was preserved. In this paper we focus on explanations for these changes via TEM investigations, Raman spectroscopy and texture measurements. The grain sizes and dislocation densities, evaluated from TEM images, showed that (i) the majority of cracks generated during high-pressure torsion are healed during annealing, leaving only small pores, that (ii) the grains have grown, and that (iii) the dislocation density is decreased. While Raman spectra indicate that after HPT processing and annealing the vibration modes related to the shorter Sb-Sb bonds in the Sb4 rings are more affected than those related to the longer Sb-Sb bonds, almost no visible changes were observed in the pole intensity and/or orientation. PMID:25556702

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

    Scientific Electronic Library Online (English)

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

    2012-02-01

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

  15. Comparative Studies of Constitutive properties of Nanocrystalline and Bulk Iron During Compressive Deformation

    Science.gov (United States)

    Yu, Xiaohui; Zhang, Jianzhong; Wang, Liping; Zhao, Yusheng

    2011-03-01

    We present a comparative study of mechanical properties of bcc nano-crystalline iron and microncrystalline iron by in-situ high-pressure synchrotron x-ray diffraction under tri-axial 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 ambient 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 nano crystals. For micron-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 micron-Fe (0.13 GPa), indicating that the nano scale grain-size reduction is a substantially more effective strengthening mechanism than the conventional carbon infusion in iron.

  16. Comparative Studies of Constitutive Properties of nanocrystalline and Bulk Iron During Compressive Deformation

    Energy Technology Data Exchange (ETDEWEB)

    X Yu; J Zhang; L Wang; Z Ding; C Jin; Y Zhao

    2011-12-31

    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 10{sup 16} m{sup -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 pressureinduced 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.

  17. Transient deformation properties of Zircaloy for LOCA simulation. Final report, Volume 1. [BWR; PWR

    Energy Technology Data Exchange (ETDEWEB)

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

    1977-12-01

    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 600/sup 0/F (589 K) to 2200/sup 0/F (1477 K) with the emphasis on the 800/sup 0/F (700/sup 0/K) to 2000/sup 0/F (1366/sup 0/K) temperature levels in low pressure air (6.5 x 10/sup -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. Results include creep/creep rupture strain numerical constitutive relationships out to 120 seconds, computer codes and ramp test data.

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

    Directory of Open Access Journals (Sweden)

    Langdon, T. G.

    2008-12-01

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

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

  19. Mechanical properties and deformation behavior of Ti-5Cr-xFe alloys

    International Nuclear Information System (INIS)

    The effects of iron on the mechanical properties and deformation behavior of a Ti-5Cr-based system were studied with emphasis on improving the strength/modulus ratio. As-cast Ti-5Cr and a series of Ti-5Cr-xFe (x = 0.1, 0.5, 1, 3 and 5 mass%) alloys prepared by using a dental cast machine were investigated. X-ray diffraction (XRD) for phase analysis was conducted with a diffractometer. Three-point bending tests were performed to evaluate the mechanical properties of all specimens. The fractured surfaces were observed by using scanning electron microscopy (SEM). Moreover, the surface morphology of a post-bending unetched specimen was examined by using an optical microscope. The experimental results indicated that only Ti-5Cr-3Fe and Ti-5Cr-5Fe alloys exhibited ductile properties. The bending moduli of the Ti-5Cr-3Fe and Ti-5Cr-5Fe alloys without an ? phase were lower than those of the Ti-5Cr and Ti-5Cr-xFe alloys with an ? phase. The Ti-5Cr-3Fe alloy exhibited highest bending strength/modulus ratios as large as 25.1, being higher than those of commercially pure titanium (c.p. Ti) by 195% and of the Ti-5Cr alloy by 132%. Moreover, the Ti-5Cr-5Fe alloy also had highest ratios as large as 24.6, being higher than those of c.p. Ti by 189% and of the Ti-5Cr alloy by 128%. Furthermore, the elastically recoverable angles of the Ti-5Cr-3Fe (31.5 deg.) and Ti-5Cr-5Fe (29.6 deg.) alloys were greater than those of c.p. Ti (2.7 deg.) by as much as 1067% and 996%, respectively. The optical micrographs indicated that the surfaces of the Ti-5Cr-3Fe and Ti-5Cr-5Fe alloys were covered with many slip bands. In the current search for better implant materials, the low modulus, ductile property, excellent elastic recovery capability and reasonably high strength (or high strength/modulus ratio) ? phase Ti-5Cr-3Fe and Ti-5Cr-5Fe alloys seem to be promising candidates

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

    Science.gov (United States)

    Raziperchikolaee, Samin

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

  1. Quantitative genetic properties of four measures of deformity in yellowtail kingfish Seriola lalandi Valenciennes, 1833.

    Science.gov (United States)

    Nguyen, N H; Whatmore, P; Miller, A; Knibb, W

    2016-02-01

    The main aim of this study was to estimate the heritability for four measures of deformity and their genetic associations with growth (body weight and length), carcass (fillet weight and yield) and flesh-quality (fillet fat content) traits in yellowtail kingfish Seriola lalandi. The observed major deformities included lower jaw, nasal erosion, deformed operculum and skinny fish on 480 individuals from 22 families at Clean Seas Tuna Ltd. They were typically recorded as binary traits (presence or absence) and were analysed separately by both threshold generalized models and standard animal mixed models. Consistency of the models was evaluated by calculating simple Pearson correlation of breeding values of full-sib families for jaw deformity. Genetic and phenotypic correlations among traits were estimated using a multitrait linear mixed model in ASReml. Both threshold and linear mixed model analysis showed that there is additive genetic variation in the four measures of deformity, with the estimates of heritability obtained from the former (threshold) models on liability scale ranging from 0.14 to 0.66 (SE 0.32-0.56) and from the latter (linear animal and sire) models on original (observed) scale, 0.01-0.23 (SE 0.03-0.16). When the estimates on the underlying liability were transformed to the observed scale (0, 1), they were generally consistent between threshold and linear mixed models. Phenotypic correlations among deformity traits were weak (close to zero). The genetic correlations among deformity traits were not significantly different from zero. Body weight and fillet carcass showed significant positive genetic correlations with jaw deformity (0.75 and 0.95, respectively). Genetic correlation between body weight and operculum was negative (-0.51, P < 0.05). The genetic correlations' estimates of body and carcass traits with other deformity were not significant due to their relatively high standard errors. Our results showed that there are prospects for genetic selection to improve deformity in yellowtail kingfish and that measures of deformity should be included in the recording scheme, breeding objectives and selection index in practical selective breeding programmes due to the antagonistic genetic correlations of deformed jaws with body and carcass performance. PMID:25683477

  2. Computer program for the relativistic mean field description of the ground state properties of even-even axially deformed nuclei

    CERN Document Server

    Ring, P; Lalazissis, G A

    1997-01-01

    A Fortran program for the calculation of the ground state properties of axially deformed even-even nuclei in the relativistic framework is presented. In this relativistic mean field (RMF) approach a set of coupled differential equations namely the Dirac equation with potential terms for the nucleons and the Glein-Gordon type equations with sources for the meson and the electromagnetic fields are to be solved self-consistently. The well tested basis expansion method is used for this purpose. Accordingly a set of harmonic oscillator basis generated by an axially deformed potential are used in the expansion. The solution gives the nucleon spinors, the fields and level occupancies, which are used in the calculation of the ground state properties.

  3. Mechanical properties of submicrocrystalline aluminium alloys after severe plastic deformation using equal channel angular extrusion

    International Nuclear Information System (INIS)

    Influence of severe plastic deformation by means of equal-channel and complex angular extrusion and of submicrocrystalline (SMC) structure on static tensile strength at room temperature of basic compositions of thermally nonstrengthened and strengthened industrially deformed aluminium alloys (Al-Mg, Al-Mg-Li-Zr) was analyzed. It is shown that a unique combination of their strength and ductility can be achieved by complex treatment including severe plastic deformation and conventional methods of thermal and strain effects in thermally nonstrengthened and low-alloy thermally strengthened alloys. The conclusion is made that imparting SMC structure by means of severe plastic deformation by angular extrusion to most complex-alloyed industrial thermally strengthened alloys to improve their static strength is not effective

  4. Dependence of the powder nickel alloy mechanical properties on the deformation temperature and rate

    International Nuclear Information System (INIS)

    Nickel superalloy of ZhS6 type has been studied. Being obtained by conventional casting this alloy cannot be subjected to deformation because of extremely low plasticity. It has been determined that the strength and plasticity of the cast nickel alloy obtained by the method of granule metallurgy at indoor temperature are 1.5 and 3.4 times as high , respectively, than those of the alloy obtained by conventional casting. It has been shown that at temperatures of 1000-1150 deg C the powder alloy shows the superplasticity effect: at low deformation rates its elongation reaches some hundreds per cent with loadings of about 0.1?sub(0.2); a relative elongation of the sample, the value of the applied loading and the deformation diagram type depend to a considerable extent on the deformation rate; with its decrease ?sub(k) sharply increases and the loading decreases

  5. Thermo-mechanical properties of a deformable mirror with screen printed actuator

    Science.gov (United States)

    Bruchmann, C.; Appelfelder, M.; Beckert, E.; Eberhardt, R.; Tünnermann, A.

    2012-03-01

    This paper reports on the thermo-mechanical modeling and characterization of a screen printed deformable mirror. The unimorph mirror offers a ceramic LTCC substrate with screen printed PZT layers on its rear surface and a machined copper layer on its front surface. We present the thermo-mechanical model of the deformable mirror based on Ansys multiphysics. The developed mirror design is practically characterized. The homogeneous loading of the optimized design results in a membrane deformation with a rate of -0.2 ?m/K, while a laser loading causes a change with a rate of 1.3 ?m/W. The proposed mirror design is also suitable to pre-compensate laser generated mirror deformations by homogeneous thermal loading (heating). We experimentally show that a 35 K pre-heating of the mirror assembly could compensate an absorbed laser power of 1.25 W.

  6. Effect of plastic deformation of a quenched maraging steel on its mechanical properties

    International Nuclear Information System (INIS)

    The after quenching effect of plastic deformation on structural strength and operation reliability of N17K12M5T ssheet maraging steel was investigated. It was determined that after double quenching and before aging plastic deformation positively affected structural strength characteristics, in particular, strength limit of fractured samples, creep-rupture strength during the test on slow destructuon in water, corrosion under stress and stress intensity coefficient

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

    Science.gov (United States)

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

    2014-08-01

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

  8. 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$\\thicksim$88 and N$\\thicksim$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.

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

    CERN Document Server

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

    2015-01-01

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

  10. Hyperfine-induced electric dipole contributions to the electric octupole and magnetic quadrupole atomic clock transitions

    CERN Document Server

    Dzuba, V A

    2016-01-01

    Hyperfine-induced electric dipole contributions may significantly increase probabilities of otherwise very weak electric octupole and magnetic quadrupole atomic clock transitions (e.g. transitions between $s$ and $f$ electron orbitals). These transitions can be used for exceptionally accurate atomic clocks, quantum information processing and search for dark matter. They are very sensitive to new physics beyond the Standard Model, such as temporal variation of the fine structure constant, the Lorentz invariance and Einstein equivalence principle violation. We formulate conditions under which the hyperfine-induced electric dipole contribution dominates. Due to the hyperfine quenching the electric octupole clock transition in $^{173}$Yb$^+$ is two orders of magnitude stronger than that in currently used $^{171}$Yb$^+$. Some enhancement is found in $^{143}$Nd$^{13+}$, $^{149}$Pm$^{14+}$, $^{147}$Sm$^{14+}$, and $^{147}$Sm$^{15+}$ ions.

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

    International Nuclear Information System (INIS)

    This thesis addresses the following key issues in the lower hybrid frequency range: 1. What are the 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

  12. Influence of cross-link structure, density and mechanical properties in the mesoscale deformation mechanisms of collagen fibrils.

    Science.gov (United States)

    Depalle, Baptiste; Qin, Zhao; Shefelbine, Sandra J; Buehler, Markus J

    2015-12-01

    Collagen is a ubiquitous protein with remarkable mechanical properties. It is highly elastic, shows large fracture strength and enables substantial energy dissipation during deformation. Most of the connective tissue in humans consists of collagen fibrils composed of a staggered array of tropocollagen molecules, which are connected by intermolecular cross-links. In this study, we report a three-dimensional coarse-grained model of collagen and analyze the influence of enzymatic cross-links on the mechanics of collagen fibrils. Two representatives immature and mature cross-links are implemented in the mesoscale model using a bottom-up approach. By varying the number, type and mechanical properties of cross-links in the fibrils and performing tensile test on the models, we systematically investigate the deformation mechanisms of cross-linked collagen fibrils. We find that cross-linked fibrils exhibit a three phase behavior, which agrees closer with experimental results than what was obtained using previous models. The fibril mechanical response is characterized by: (i) an initial elastic deformation corresponding to the collagen molecule uncoiling, (ii) a linear regime dominated by molecule sliding and (iii) the second stiffer elastic regime related to the stretching of the backbone of the tropocollagen molecules until the fibril ruptures. Our results suggest that both cross-link density and type dictate the stiffness of large deformation regime by increasing the number of interconnected molecules while cross-links mechanical properties determine the failure strain and strength of the fibril. These findings reveal that cross-links play an essential role in creating an interconnected fibrillar material of tunable toughness and strength. PMID:25153614

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

    International Nuclear Information System (INIS)

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

  14. Relative spins and excitation energies of superdeformed bands in $^{190}$Hg further evidence for octupole vibration

    CERN Document Server

    Crowell, B; Janssens, R V F; Blumenthal, D J; Wilson, A N; Sharpey-Schafer, J F; Nakatsukasa, T; Ahmad, I; Astier, A; Azaiez, F; Du Croix, L; Gall, B J P; Hannachi, F; Khoo, T L; Korichi, A; Lauritsen, T; López-Martens, A; Meyer, M R; Nisius, D; Paul, E S; Porquet, M G; Redon, N; Crowell, B; Carpenter, M P; Janssens, R V F; Blumenthal, D J; Wilson, A N; Sharpey-Schafer, J F; Nakatsukasa, T; du Croux, L; Gall, B J P; Hannachi, F; Khoo, T L; Korichi, A; Lauritsen, T; Lopez-Martens, A; Meyer, M; Nisius, D; Paul, E S; Porquet, M G; Redon, N

    1994-01-01

    An experiment using the Eurogam Phase II gamma-ray spectrometer confirms the existence of an excited superdeformed (SD) band in 190Hg and its very unusual decay into the lowest SD band over 3-4 transitions. The energies and dipole character of the transitions linking the two SD bands have been firmly established. Comparisons with RPA calculations indicate that the excited SD band can be interpreted as an octupole-vibrational structure.

  15. Microscopic investigation of octupole modes of oscillation via analyzing power measurements

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

    Leung, Kent; Zimmer, Oliver

    2008-01-01

    The current knowledge of the neutron $\\beta$-decay lifetime has come under scrutiny as of late due to large disagreements between recent precise measurements. Measurements using magnetically trapped Ultra-Cold Neutrons (UCNs) offer the possibility of storage without spurious losses which can provide a reliable value for the neutron lifetime. The progress towards realizing a neutron lifetime measurement using a Ioffe-type trap made with a Halbach-type permanent octupole magnet is presented her...

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

    Science.gov (United States)

    Hennig, Andreas; Spieker, Mark; Werner, Volker; Ahn, Tan; Anagnostatou, Vassia; Cooper, Nathan; Derya, Vera; Elvers, Michael; Endres, Janis; Goddard, Phil; Heinz, Andreas; Hughes, Richard O.; Ilie, Gabriela; Mineva, Milena N.; Pickstone, Simon G.; Petkov, Pavel; Pietralla, Norbert; Radeck, Desirée; Ross, Tim J.; Savran, Deniz; Zilges, Andreas

    2015-05-01

    In addition to the well-established quadrupole mixed-symmetry states, octupole and hexadecapole excitations with mixed-symmetry character have been recently proposed for the N = 52 isotones 92Zr and 94Mo. We performed two inelastic proton-scattering experiments to study this kind of excitations in the heaviest stable N = 52 isotone 96Ru. From the combined experimental data of both experiments absolute transition strengths were extracted.

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

    Directory of Open Access Journals (Sweden)

    Hennig Andreas

    2015-01-01

    Full Text Available In addition to the well-established quadrupole mixed-symmetry states, octupole and hexadecapole excitations with mixed-symmetry character have been recently proposed for the N = 52 isotones 92Zr and 94Mo. We performed two inelastic proton-scattering experiments to study this kind of excitations in the heaviest stable N = 52 isotone 96Ru. From the combined experimental data of both experiments absolute transition strengths were extracted.

  19. Relative spins and excitation energies of superdeformed bands in 190Hg: Further evidence for octupole vibration

    International Nuclear Information System (INIS)

    An experiment using the Eurogam phase II ?-ray spectrometer confirms the existence of an excited superdeformed (SD) band in 190Hg and its very unusual decay into the lowest SD band over 3--4 transitions. The energies of the transitions linking the two SD bands have been firmly established, and their angular distributions are consistent with a dipole character. Comparisons with calculations using random-phase approximation indicate that the excited SD band can be interpreted as an octupole-vibrational structure

  20. 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.

  1. Evolution of structure and physical-mechanical properties of iron under deformation

    Energy Technology Data Exchange (ETDEWEB)

    Bukhvalov, A.B.; Gorkunov, E.S. [Academy of Sciences, Ekaterinburg (Russian Federation). Inst. of Engineering Science

    1999-09-01

    The dependencies of true yield stresses s on true tensile strain values {epsilon} were experimentally determined on the specimens of technically pure iron after cold rolling and after annealing at different temperatures. The correlations between strain values {epsilon} and coercivity H{sub c} which made a basis for nondestructive evaluation of residual deformations of structural elements and machine components were investigated. It has been shown that there is the unique relation between the yield strength and grain sizes in recrystallized iron and also the disoriented subgrain sizes in polygonized iron. The strain hardening curves of exponential type were reconstructed by a method of approximation for two structural states of iron - recrystallized and polygonized. Under low and medium deformations (before the formation of the neck) the growth of the yield stresses s is mainly caused by the strain hardening. Within the interval of large deformation, as {epsilon} grows, the contribution by tension-shear deformation modes increases. As a result, the dislocation density is increasingly influenced by the formation of the fragmentary structure along the strain axis. The feedback equations {epsilon}(H{sub c}) were derived, that can be used for evaluation of the residual deformation by magnetic nondestructive testing methods. (orig.)

  2. Mechanical properties and local mobility of atactic-polystyrene films under constant-shear deformation.

    Science.gov (United States)

    Hudzinskyy, D; Michels, M A J; Lyulin, A V

    2012-09-28

    We have performed molecular-dynamics simulations of atactic polystyrene thin films to study the effect of shear rate, pressure, and temperature on the stress-strain behaviour, the relevant energetic contributions and non-affine displacements of polymer chains during constant-shear deformation. Under this deformation sliding motion is observed at high shear rates between the top substrate and top polymer layer, which disappears when the shear rate decreases. At low shear rates stick-slip motion of the whole film with respect to the bottom substrate takes place. We found that at low shear rates the yield stress logarithmically depends on the shear rate; this behaviour can be explained in terms of the Eyring model. It was also observed that an increase in the normal pressure leads to an increase in the yield stress in agreement with experiments. The contributions to the total shear stress and energy are mainly given by the excluded-volume interactions. It corresponds to a local translational dynamics under constant shear in which particles are forced to leave their original cages much earlier as compared to the case of the isotropic, non-sheared film. Moreover, it was observed that under constant-shear deformation the polymer glass is deformed non-affinely. As a result, the middle part of the film is much more deformed than the layers close to the supporting substrates, meaning that the well-known effect of shear-banding occurs. PMID:23020347

  3. Tidal deformations of a spinning compact object

    CERN Document Server

    Pani, Paolo; Maselli, Andrea; Ferrari, Valeria

    2015-01-01

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

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Sahin, Mumin [Mechanical Engineering Department, Engineering and Architecture Faculty, Trakya University, 22180 Edirne (Turkey)], E-mail: mumins@trakya.edu.tr

    2009-01-15

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

  6. 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.

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

    Science.gov (United States)

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

    2009-10-01

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

  8. Deformation and Fracture Properties in Neutron Irradiated Pure Mo and Mo Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Byun, T.S.; Snead, L. [ORNL, Oak Ridge National Laboratory, Bldg. 9201-2, MS-8072, Oak Ridge, Tennessee, TN 37831-8072 (United States); Li, M. [Oak Ridge Noational Laboratory, PO 2008, MS 6138, Oak Ridge, TN 37931-6138 (United States); Cockeram, B.V. [Bettis Atomic Power Laboratory, West Mifflin, AK PA 15122 (United States)

    2007-07-01

    Full text of publication follows: The evolution in microstructural and mechanical properties was investigated for molybdenum and molybdenum alloys after high temperature neutron irradiation. Test materials include oxide dispersion-strengthened (ODS) molybdenum alloy, molybdenum- 0.5% titanium-0.1% zirconium (TZM) alloy, and low carbon arc-cast (LCAC) molybdenum. Tensile specimens were irradiated in high flux isotope reactor (HFIR) at temperatures in the range {approx}300 - 1000 deg. C to neutron fluences of 2.28 - 24.7 x 10{sup 25} n/m{sup 2} (E>0.1 MeV) or 1.2-13.1 dpa. Tensile tests were performed at temperatures ranging from -150 deg. C to 1000 deg. C. To evaluate irradiation effects, true stress parameters (yield stress, plastic instability stress, and true fracture stress) and ductility parameters (uniform strain, fracture strain, and reduction area) were compared for both irradiated and non-irradiated materials. Fracture toughness was also evaluated from the fracture stress and fracture strain data using a fracture strain model. The fracture strain was used to determine the ductile-to-brittle transition temperature (DBTT). Results indicate that irradiation in the temperature range of 600 - 800 deg. C hardened the materials by up to 70%, while the irradiation hardening outside this temperature range was much lower (<40%). The plastic instability stress was strongly dependent on test temperature; however, it was nearly independent of irradiation dose and temperature. It was also found that the true fracture stress was dependent on test temperature. The true fracture stress was not significantly influenced by irradiation at elevated and high test temperatures; however, it was decreased significantly at sub-zero temperatures after irradiation due to material embrittlement. The DBTT for 600 deg. C irradiated ODS molybdenum alloy was found to be about room temperature or lower, and among the test materials the ODS alloy showed the highest resistance to irradiation embrittlement. The as-irradiated and deformed microstructures were characterized by TEM and compared to explain the high toughness behavior of the ODS alloy. (authors)

  9. 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

  10. Effect of bimodal harmonic structure design on the deformation behaviour and mechanical properties of Co-Cr-Mo alloy.

    Science.gov (United States)

    Vajpai, Sanjay Kumar; Sawangrat, Choncharoen; Yamaguchi, Osamu; Ciuca, Octav Paul; Ameyama, Kei

    2016-01-01

    In the present work, Co-Cr-Mo alloy compacts with a unique bimodal microstructural design, harmonic structure design, were successfully prepared via a powder metallurgy route consisting of controlled mechanical milling of pre-alloyed powders followed by spark plasma sintering. The harmonic structured Co-Cr-Mo alloy with bimodal grain size distribution exhibited relatively higher strength together with higher ductility as compared to the coarse-grained specimens. The harmonic Co-Cr-Mo alloy exhibited a very complex deformation behavior wherein it was found that the higher strength and the high retained ductility are derived from fine-grained shell and coarse-grained core regions, respectively. Finally, it was observed that the peculiar spatial/topological arrangement of stronger fine-grained and ductile coarse-grained regions in the harmonic structure promotes uniformity of strain distribution, leading to improved mechanical properties by suppressing the localized plastic deformation during straining. PMID:26478398

  11. 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

  12. Mechanical and electrical properties of blood and evaluation of RBC aggregation and deformability.

    Czech Academy of Sciences Publication Activity Database

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

    Warsaw : International Centre of Biocybernetics (ICB), 2012 - (Bedzinski, R.; Petrtyl, M.), s. 28-32 [ Current trends in development of implantable tissue structures. Warsaw (PL), 18.04.2012-20.04.2012] Institutional support: RVO:67985874 Keywords : apparent viscosity * conductivity * dextrans * glutaraldehyde * RBC aggregation * RBC deformability Subject RIV: JB - Sensors, Measurment, Regulation

  13. Peculiarities of strength and deformability properties of clay soils in districts of Western Siberia

    Science.gov (United States)

    Efimenko, Sergey; Efimenko, Vladimir; Sukhorukov, Alexey

    2016-01-01

    The article demonstrates the methodology of the substantiation of the calculated values of moisture, strength, and deformability characteristics of clay subgrade soils for the design of pavements by strength conditions in II, III, and IV road-climatic zones in West Siberia. The main purpose of the work is to ensure the quality of the design of roads in newly developed regions of Russia. To achieve this goal the following problems have been solved: the dislocation of boundary lines of road-climatic zones has been specified, zoning of the investigated territory for the design of roads has been detailed; regularities of changes in strength and deformability characteristics of clay subgrade soils of their moisture have been established; the territorial normalization of the calculated values of moisture, strength, and deformability of clay subgrade soils in relation to the allocated road districts has been carried out. Specification of boundary lines of road-climatic zones has been implemented on the basis of the taxonomic system "zone-subzone-road district". The calculated values of moisture, strength, and deformability characteristics of clay soils, established and differentiated according to road-climatic zones, will ensure the required level of the reliability of transport infrastructure facilities during the life cycle of roads.

  14. A physical interpretation for the stability property of a localized disturbance in a deformation flow

    International Nuclear Information System (INIS)

    The relationship between the local shape of an unstable disturbance and the basic deformation field has been put forward by Mak and Cai as a general condition for barotropic instability of a zonally varying nondivergent basic flow. The general condition states that an unstable disturbance has to be elongated locally at an angle of less than 45 degrees along the axis of contraction of the basic deformation field. The conventional condition for barotropic instability of a zonally uniform basic flow (an unstable disturbance necessarily leans against the basic shear) is a special case of the general condition. To physically interpret the general condition, we have analyzed the immediate subsequent evolution of a localized elliptic-shaped disturbance (defined in terms of streamfunction) embedded in a purely deformation flow. The localized disturbance has the minimum kinetic energy and enstrophy when its shape is circular. Under the influence of the basic deformation, the disturbance tends to shrink along the axis of contraction and to expand along the axis of dilatation. Hence, the disturbance with the major axis along the axis of contraction would deform toward a circle shape. The change in eccentricity of such a disturbance alone acts to reduce its total energy and enstrophy. Because of the conservation constraint of the total perturbation enstrophy, the amplitude of the disturbance has to increase as its eccentricity decreases. The energy change due to the change in amplitude overwhelms that resulting from the change in eccentricity. Therefore, the overall kinetic energy of the localized disturbance tends to increase with time during the course of its evolution. The same arguments also explain why the disturbance with major axis along the axis of dilatation is decaying. 9 refs., 3 figs

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

    Directory of Open Access Journals (Sweden)

    Dave Maharaj

    2014-06-01

    Full Text Available 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.

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

    Science.gov (United States)

    Maharaj, Dave; Bhushan, Bharat

    2014-01-01

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

  17. Effect of rolling deformation and solution treatment on microstructure and mechanical properties of a cast duplex stainless steel

    Indian Academy of Sciences (India)

    S K Ghosh; D Mahata; R Roychaudhuri; R Mondal

    2012-10-01

    The present study deals with the effect of rolling deformation and solution treatment on the microstructure and mechanical properties of a cast duplex stainless steel. Cast steel reveals acicular/Widmanstätten morphology as well as island of austenite within the -ferrite matrix. Hot rolled samples exhibit the presence of lower volume percent of elongated band of -ferrite (∼40%) and austenite phase which convert into finer and fragmented microstructural constituents after 30% cold deformation. By the solution treatment, the elongated and broken crystalline grains recrystallize which leads to the formation of finer grains (<10 m) of austenite. X-ray diffraction analysis has corroborated well with the above-mentioned microstructural investigation. Enhancement in hardness, yield strength and tensile strength values as well as drop in percent elongation with cold deformation increases its suitability for use in thinner sections. 30% cold rolled and solution treated sample reveals attractive combination of strength and ductility (25.22 GPa%). The examination of fracture surface also substantiates the tensile results. The sub-surface micrographs provide the potential sites for initiation of microvoids.

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

    International Nuclear Information System (INIS)

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

  19. Structure and mechanical behaviour of an aluminium alloy AMg6 after severe plastic deformation and annealing: 2. Mechanical properties

    International Nuclear Information System (INIS)

    The peculiarities of the mechanical behavior at the room temperature of the AMg6 industrial aluminium alloy with submicro- and microcrystalline structures, obtained through intensive plastic deformation (IPD) by the equichannel angular pressing and subsequent annealing, are considered. The effect of the structural state on the discontinuous fluidity and characteristics of the alloy static strength, including crack resistance, is analyzed. The conclusion is made, that IPD of the AMg6 alloy increased its tensile properties at the room temperature. The obtained data, however, present no basis for the conclusion on the IPD favorable effect on the alloy plasticity

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

    DEFF Research Database (Denmark)

    Krogsbøll, Anette; Hededal, Ole; Foged, Niels Nielsen

    2012-01-01

    The geological preconsolidation of the Palaeogene clays in Denmark is estimated to 5-8 MPa or more, whereas laboratory and field experiences indicate values between 100 and 3000 kPa. Presumably, the high plasticity clay loses its memory of earlier preloads due to swelling, or as an effect of fissuring or debonding. Based on a large amount of high quality tests on Palaeogene clay partly encountered at Fehmarn Belt the typical deformational behaviour during unloading and swelling is discussed and ...

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

    Science.gov (United States)

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

    2013-05-01

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

  2. 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 β3 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 β3. The literature has been covered to March 1988

  3. 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)

    Yang Fei

    2010-11-01

    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 ?.

  4. Toroidal resonance: relation to pygmy mode, vortical properties and anomalous deformation splitting

    CERN Document Server

    Nesterenko, V O; Repko, A; Kleinig, W; Reinhard, P -G

    2016-01-01

    We review a recent progress in investigation of the isoscalar toroidal dipole resonance (TDR). A possible relation of the TDR and low-energy dipole strength (also called a pygmy resonance) is analyzed. It is shown that the dipole strength in the pygmy region can by understood as a local manifestation of the collective vortical toroidal motion at the nuclear surface. Application of the TDR as a measure of the nuclear dipole vorticity is discussed. Finally, an anomalous splitting of the TDR in deformed nuclei is scrutinized.

  5. Grain size effects on the tensile properties and deformation mechanisms of a magnesium alloy, AZ31B, sheet

    International Nuclear Information System (INIS)

    The grain size dependence of the tensile properties and the deformation mechanisms responsible for those properties are examined for Mg alloy, AZ31B, sheet. Specifically, the Hall-Petch effect and strain anisotropy (r-value) are characterized experimentally, and interpreted using polycrystal plasticity modeling. {1 0 . 2} extension twins, {1 0 . 1} contraction twins, and so-called 'double-twins' are observed via microscopy and diffraction-based techniques, and the amount of twinning is found to increase with increasing grain size. For the sheet texture and tensile loading condition examined, {1 0 . 2} extension twinning is not expected, yet the polycrystal plasticity model predicts the observed behavior, including this 'anomalous' tensile twinning. The analysis shows that the Hall-Petch strength dependence, of the polycrystal as a whole, is primarily determined by the grain size dependence of the strength of the prismatic slip systems

  6. 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)

  7. Electric-dipole transitions and octupole softness in odd-A rare-earth nuclei

    International Nuclear Information System (INIS)

    It is found that B(E1) values calculated by using a model, in which one quasiparticle is coupled to a rotor, are more than an order of magnitude too small compared with measured B(E1) values in low-energy transitions observed in the yrast spectroscopy of odd-A rare-earth nuclei. Thus, the measured B(E1) values are analyzed by introducing the parameters which effectively take into account the octupole softness. An estimate of the parameters based on a microscopic model is made, and a discrepancy between the estimated values and the values necessary for reproducing data is found. (au)

  8. High-power ion-cyclotron-resonance heating in the Wisconsin Levitated Octupole

    International Nuclear Information System (INIS)

    Ion cyclotron resonance heating has been investigated, both experimentally and theoretically, on the Wisconsin Levitated Octupole. Heating of both ions and electrons has been observed. Typically, a two component ion energy distribution is produced (300 eV and 50 eV) with the application of 500 kW of rf power into a 5 x 1012 cm-3 density plasma. Power is coupled to the plasma with an antenna that also serves as the inductor of an oscillator tank circuit. The oscillator is tunable from 1 to 3 MHz and can be applied for periods up to 10 msec. The experiments were performed with hydrogen, gun injected plasmas

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

    CERN Document Server

    Leung, Kent

    2008-01-01

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

  10. Influence of temperature of intensive plastic deformation (at 300 and at 77 K) on return of physical-mechanical properties of zirkonium

    International Nuclear Information System (INIS)

    Influence of intensive plastic (IP) deformation of rolling on 90% at 300 and 77 K, and the subsequent isochronous annealings in an interval 373...773 K on structure and physical-mechanical properties of iodide zirconium is investigated. It is shown, that as a result of IP deformation of rolling at 300 and 77 K the density of dislocations increases from 108 cm-2 up to 1011 cm-2, nanostructure (with the size of subgrains ? 100 nm) is formed, microhardness on 80 and 125%, and resistivity on 13,5 and 25% increase according to temperatures of deformation, and dislocation peak of internal friction appears at 150 K. The stages of return are determined, and it is shown that the decreasing temperature of deformation from 300 up to 77 K reduces heat resistance of a substructure and physical-mechanical properties of zirconium.

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

    CERN Document Server

    Fang, Dong-Liang; Suzuki, Toshio

    2012-01-01

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

  12. Experimental Study of the Bending Properties and Deformation Analysis of Web-Reinforced Composite Sandwich Floor Slabs with Four Simply Supported Edges

    OpenAIRE

    Qi, Yujun; Fang, Hai; Liu, Weiqing

    2016-01-01

    Web-reinforced composite sandwich panels exhibit good mechanical properties in one-way bending, but few studies have investigated their flexural behavior and deformation calculation methods under conditions of four simply supported edges. This paper studies the bending performance of and deformation calculation methods for two-way web-reinforced composite sandwich panels with different web spacing and heights. Polyurethane foam, two-way orthogonal glass-fiber woven cloth and unsaturated resin...

  13. Effects of Coupled Structural and Diagenetic Processes on Deformation Localization and Fluid Flow Properties in Sandstone Reservoirs of the Southwestern United States

    Science.gov (United States)

    Elliott, S. J.; Eichhubl, P.; Landry, C. J.

    2014-12-01

    Fluid flow tends to be restricted perpendicular to deformation bands through the combined effects of mechanical grain size reduction, porosity loss, and preferred cementation relative to the adjacent host rock. Deformation bands that occur in association with reservoir scale faults can impact reservoir-scale fluid flow and fault seal behavior, potentially imparting a permeability anisotropy to reservoir rocks. We use a combination of Hg-intrusion porosimetry, high-resolution 2D-image analysis of pore size distributions, and detailed compositional analyses obtained from integrating petrographic and SEM-based imaging techniques, including SEM-cathodoluminescence, backscattered electron imaging, and energy-dispersive X-ray spectroscopy, to (1) assess the effects of coupled chemical and mechanical processes leading to deformation localization within various detrital compositions [Cedar Mesa, Navajo, and Entrada sandstones] and (2) to quantify the effect of these processes on single and multiphase fluid flow as a function of host rock properties, structural position, and deformation band textural and diagenetic properties. Within each sample, bands of differing kinematic properties and structural style, i.e. shear bands, shear enhanced compaction bands etc., were identified and pre-kinematic pore-filling cements, as well as syn- and post-kinematic cements including various clay minerals, were distinguished for both the host rock and associated deformation bands. Although the deformation bands display a variety of textures and diagenetic attributes, initial petrophysical results suggest that the flow properties - permeability and capillary pressure curves - of the bands in the formations studied are very similar. However, both individual and clustered deformation bands of the Navajo Sandstone contain open or partially cemented cross-cutting fractures that could act as flow pathways across the deformation bands.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-02-24

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-05-15

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

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

    CERN Document Server

    Peru, S

    2008-01-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Lari Baghal, S.M. [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, P.O. Box 11155-4563, Tehran (Iran, Islamic Republic of); Amadeh, A., E-mail: amadeh@ut.ac.ir [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, P.O. Box 11155-4563, Tehran (Iran, Islamic Republic of); Heydarzadeh Sohi, M. [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, P.O. Box 11155-4563, Tehran (Iran, Islamic Republic of)

    2012-04-30

    Highlights: Black-Right-Pointing-Pointer The tensile properties of Ni-Co and Ni-Co/SiC deposits were investigated. Black-Right-Pointing-Pointer The SiC particles enhanced tensile strength and ductility of nano-structured composites. Black-Right-Pointing-Pointer 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.

  18. 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.

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

    Directory of Open Access Journals (Sweden)

    Yurkova A.I.

    2012-08-01

    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.

  20. Effect of preliminary plastic deformation on mechanical properties and microstructure of structural steel

    International Nuclear Information System (INIS)

    Preliminary tension has been studied for the effect of its degree on the mechanical characteristics and microstructure of steel 15Kh2MFA with ?0.2-540 and 950 MPa. Different mechanisms of steel failure are determined depending on the yield point level. At the first stage of plastic deformation of smooth specimens formation and growth of micorpores in both steels proceed in force direction. Then steel 15Kh2MFA (I) shows not only the longitudinal growth of pores but also the transversal growth as well as mutual coalescence, which is responsible for the pit fracture. Steel 15Kh2MFA (II) retains the longitudinal growth and coalescence of pores up to the formation of microcracks and longitudinal separation into layers at the stage preceeding the specimen complete failure. In this case grain-boundary quasi-brittle fracture is mainly observed

  1. Kondo effects in a triangular triple quantum dot II: ground-state properties for deformed configurations

    Science.gov (United States)

    Oguri, Akira; Amaha, Shinichi; Nisikawa, Yunori; Hewson, A. C.; Tarucha, Seigo; Numata, Takahide

    2010-03-01

    We study transport through a triangular triple quantum dot (TTQD) connected to two noninteracting leads, using the numerical renormalization group. The system has been theoretically revealed to show a variety of Kondo effects depending on the electron filling of the triangle [1]. For instance, the SU(4) Kondo effect takes place at three-electron filling, and a two-stage Kondo screening of a high-spin S=1 Nagaoka state takes place at four-electron filling. Because of the enhanced freedom in the configurations, however, the large parameter space of the TTQD still has not been fully explored, especially for large deformations. We report the effects of the inhomogeneity in the inter-dot couplings and the level positions in a wide region of the filling. [1] T. Numata, Y. Nisikawa, A. Oguri, and A. C. Hewson: PRB 80, 155330 (2009).

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

    Energy Technology Data Exchange (ETDEWEB)

    Stepanov, G.V., E-mail: gstepanov@mail.ru [Institute of Chemistry and Technology of Organoelement Compounds, Sh. Entuziastov 128, Moscow 111123 (Russian Federation); Chertovich, A.V. [Physics Department, Moscow State University, Moscow 119991 (Russian Federation); Kramarenko, E.Yu., E-mail: kram@polly.phys.msu.ru [Physics Department, Moscow State University, Moscow 119991 (Russian Federation)

    2012-10-15

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

  3. Persistence of octupole correlations in sup 2 sup 3 sup 1 Ra

    CERN Document Server

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

    2001-01-01

    The structure of sup 2 sup 3 sup 1 Ra, the heaviest odd Ra nucleus currently accessible for detailed spectroscopic investigation, has been studied in the beta sup - decay of sup 2 sup 3 sup 1 Fr. The main purpose has been to verify whether fast B(E1) rates and significant octupole correlations recently established in sup 2 sup 2 sup 9 Ra persist in sup 2 sup 3 sup 1 Ra. The excited states in sup 2 sup 3 sup 1 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 suppi=5/2 sup+- and K suppi=1/2 sup+- bands, reveal the persistence of octupole collective effects in sup 2 sup 3 sup 1 Ra, although the B(E1) rates are lower than in sup 2 sup 2 sup 9 Ra. These findings reinforce the differences in the B(E1) systematics between isotonic Ra and Th ...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-09-06

    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.

  5. Design of a collision cell coupled to an octupole in order to study ionic complexes

    International Nuclear Information System (INIS)

    The study of chemical reactivity within mixed ionic metal-water complexes, e.g.M(H2O)n+ with 1 2O)n+ complexes, we have developed a collision cell coupled to an octupole. The development of this chamber was realized on the base of ions trajectories numerical simulations. Collision cell parameters are defined in agreement with collisional dynamics laws and allow measurements of accurate reaction cross sections. In particular, the octupole, directly placed inside the collision chamber, traps in-coming complex ions as well as ionic products of the collisions along the propagation axis z, and collects them for further analysis. The cell contains a specific adjustment tool that slows down in-coming ionic complexes before collision. The system is efficient along the z axis for a kinetic energy range of in-coming complexes between 10 and 520 eV in the laboratory referential. This device will be used to study the behaviour of metallic ions in solution and will have applications in fields like reprocessing and nuclear wastes storage. (author)

  6. Inhomogeneity on texture, microstructure and magnetic properties of hot deformed R2Fe14B-typed magnet

    Science.gov (United States)

    Lee, Y. I.; Shih, C. W.; Chang, W. C.; Chang, H. W.; Chen, Y. J.

    2015-03-01

    The inhomogeneity on texture, microstructure and magnetic properties of hot deformed (HD) disc shape R2Fe14B-typed magnets along radial and axial directions has been investigated. HD disc shape NdFeB magnet exhibits inhomogeneous texture, grain morphologies and magnetic properties not only along the radial direction but also along the axial direction. Higher magnetic properties can be found in the middle part of the HD magnet, due to the existence of larger volume fraction of plate-like Nd2Fe14B grains and the well c-axis alignment parallel to the pressing direction. In addition, particle-like and coarser grains are easily found not only in the bottom but also in the edge of the HD magnet, which may degrade the magnetic performance of the samples cut from those parts. Owing to the inhomogeneity of (00L) texture and grain morphologies along axial and radial directions, the optimal magnetic properties of Br = 12.7 kG, Hci = 5.1 kOe and (BH)max = 39 MGOe can be obtained only in the middle sample of HD magnet with slight polishing the top and bottom surfaces.

  7. Multipole modes in deformed nuclei within the finite amplitude method

    CERN Document Server

    Kortelainen, M; Nazarewicz, W

    2015-01-01

    Background: To access selected excited states of nuclei, within the framework of nuclear density functional theory, the quasiparticle random phase approximation (QRPA) is commonly used. Purpose: We present a computationally efficient, fully self-consistent framework to compute the QRPA transition strength function of an arbitrary multipole operator in axially-deformed superfluid nuclei. Methods: The method is based on the finite amplitude method (FAM) QRPA, allowing fast iterative solution of QRPA equations. A numerical implementation of the FAM-QRPA solver module has been carried out for deformed nuclei. Results: The practical feasibility of the deformed FAM module has been demonstrated. In particular, we calculate the quadrupole and octupole strength in a heavy deformed nucleus $^{240}$Pu, without any truncations in the quasiparticle space. To demonstrate the capability to calculate individual QRPA modes, we also compute low-lying negative-parity collective states in $^{154}$Sm. Conclusions: The new FAM imp...

  8. Elastic Deformation Properties of Implanted Endobronchial Wire Stents in Benign and Malignant Bronchial Disease: A Radiographic In Vivo Evaluation

    International Nuclear Information System (INIS)

    Purpose: To evaluate the long-term mechanical behavior in vivo of expandable endobronchial wire stents, we imaged three different prostheses in the treatment of tracheobronchial disease. Methods: Six patients with bronchial stenoses (three benign, three malignant) underwent insertion of metallic stents. Two self-expandable Wallstents, two balloon-expandable tantalum Strecker stents and two self-expandable nitinol Accuflex stents were used. Measurements of deformation properties were performed during voluntary cough by means of fluoroscopy, at 1 month and 7-10 months after implantation. The procedures were videotaped, their images digitized and the narrowing of stent diameters calculated at intervals of 20 msec. Results: After stent implantation all patients improved with respect to ventilatory function. Radial stent narrowing during cough reached 53% (Wallstent), 59% (tantalum Strecker stent), and 52% (nitinol Accuflex stent) of the relaxed post-implantation diameter. Stent compression was more marked in benign compared with malignant stenoses. In the long term permanent deformation occurred with the tantalum Strecker stents; the other stents were unchanged. Conclusion: Endobronchial wire stents can be helpful in the treatment of major airway collapse and obstructing bronchial lesions. However, evidence of material fatigue as a possible effect of exposure to recurrent mechanical stress on the flexible mesh tube may limit their long-term use. This seems to be predominantly important in benign bronchial collapse

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2012-09-01

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

  11. Structure and mechanical properties of aging Al-Li-Cu-Zr-Sc-Ag alloy after severe plastic deformation by high-pressure torsion

    Science.gov (United States)

    Kaigorodova, L. I.; Rasposienko, D. Yu.; Pushin, V. G.; Pilyugin, V. P.; Smirnov, S. V.

    2015-04-01

    The structural and phase transformations have been studied in aging commercial aluminum-lithium alloy Al-1.2 Li-3.2 Cu-0.09 Zr-0.11 Sc-0.4 Ag-0.3 Mg in the as-delivered state and after severe plastic deformation by torsion for 1, 5 and 10 revolutions under a high pressure of 4 GPa. Deformation-induced nanofragmentation and dynamic recrystallization have been found to occur in the alloy. The degree of recrystallization increases with deformation. Nanofragmentation and recrystallization processes are accompanied by the deformation-induced decomposition of solid solution and changes in both the nucleation mechanism of precipitation and the phase composition of the alloy. The influence of a nanostructured nanophase state of the alloy on its mechanical properties (microhardness, plasticity, elastic modulus, and stiffness) is discussed.

  12. Effect of hydrogen on the low-temperature deformation properties of neutron-irradiated vanadium

    International Nuclear Information System (INIS)

    The influence of hydrogen on the low temperature deformation characteristics of neutron-irradiated vanadium single crystals has been investigated in compression in the temperature range from 77 to 5500K. The addition of hydrogen to neutron-irradiated vanadium causes a local perturbation in the temperature dependence of yield stress that is similar to unirradiated vanadium. A mechanism based on the stress induced reorientation of small hydrides by the stress fields of moving dislocations has been put forward to account for this observation. In contrast, the presence of hydrogen prior to irradiation results only in a general rise in the yield stress. The disappearance of the local perturbation is attributed to the trapping of hydrogen atoms to form stable complexes during irradiation, thereby eliminating the phenomenon of stress-induced reorientation of hydrides. The fact that the hydrogen does not reduce the thermal component of the yield stress implies that the cancellation of neutron-produced defects by hydrogen is unlikely. The effect of prestraining prior to neutron irradiation resulted in a reduction of the increase in the yield stress due to the neutron irradiation. This reduction is probably due to the fact that the additional dislocations provide an increased sink density

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

    Science.gov (United States)

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

    2013-07-01

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

  14. Self-consistent picture of the interplay of quadrupole and octupole degrees of freedom in many-boson systems

    International Nuclear Information System (INIS)

    The interplay between quadrupole and octupole distortions is analysed within a self-consistent description of many interacting boson systems. The coupling between these degrees of freedom is studied through the relative positions of the positive- and negative-parity rotational bands. Excited bandheads, moments of inertia and multipole moments are also analysed. (orig.)

  15. 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.

  16. Octupole correlations in neutron-rich {sup 143,145}Ba and a type of superdeformed band in {sup 145}Ba

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, S.J.; Wang, M.G.; Long, G.L.; Zhu, L.Y.; Gan, C.Y.; Yang, L.M.; Sakhaee, M.; Li, M.; Deng, J.K. [Physics Department, Tsinghua University, Beijing 100084, Peoples Republic of (China); Zhu, S.J.; Hamilton, J.H.; Ramayya, A.V.; Jones, E.F.; Hwang, J.K.; Zhang, X.Q.; Gore, P.M.; Peker, L.K.; Drafta, G.; Babu, B.R.; Deng, J.K.; Ginter, T.N.; Beyer, C.J.; Kormicki, J.; Ter-Akopian, G.M.; Daniel, A.V. [Physics Department, Vanderbilt University, Nashville, Tennessee 37235 (United States); Zhu, S.J.; Ter-Akopian, G.M.; Daniel, A.V. [Joint Institute for Heavy Ion Research, Oak Ridge, Tennessee 37831 (United States); Ma, W.C. [Physics Department, Mississippi State University, Mississippi 39762 (United States); Cole, J.D.; Aryaeinejad, R.; Drigert, M.W. [Idaho National Engineering Laboratory, Idaho Falls, Idaho 83415 (United States); Rasmussen, J.O.; Asztalos, S.; Lee, I.Y.; Macchiavelli, A.O.; Chu, S.Y.; Gregorich, K.E.; Mohar, M.F. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Ter-Akopian, G.M.; Daniel, A.V.; Oganessian, Y.T.; Kliman, J. [Flerov Laboratory for Nuclear Reactions, Joint Institute for Nuclear Research, Dubna (Russia); Donangelo, R. [Universidade Federal do Rio de Janeiro, Caixa Postal 68528, RG (Brazil); Stoyer, M.A.; Lougheed, R.W.; Moody, K.J.; Wild, J.F. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Prussin, S.G. [Nuclear Engineering Department, University of California at Berkeley, Berkeley, California 94720 (United States); Kliman, J. [Institute of Physics, SASc, Dubravskacesta 9, 84228 Bratislava (Slovakia); Griffin, H.C. [University of Michigan, Ann Arbor, Michigan 48104 (United States)

    1999-11-01

    High spin states in neutron-rich odd-{ital Z} {sup 143,145}Ba nuclei have been investigated from the study of prompt {gamma} rays in the spontaneous fission of {sup 252}Cf by using {gamma}-{gamma}- and {gamma}-{gamma}-{gamma}- coincidence techniques. Alternating parity bands are identified for the first time in {sup 145}Ba and extended in {sup 143}Ba. 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 {sup 145}Ba. Enhanced E1 transitions between the negative- and positive-parity bands in these nuclei give evidence for strong octupole deformation in {sup 143}Ba and in {sup 145}Ba. These collective bands show competition and coexistence between symmetric and asymmetric shapes in {sup 145}Ba. Evidence is found for crossing M1 and E1 transitions between the s=+i and s={minus}i doublets in {sup 143}Ba. {copyright} {ital 1999} {ital The American Physical Society}

  17. Properties enhancement and recoil loop characteristics for hot deformed nanocrystalline NdFeB permanent magnets

    International Nuclear Information System (INIS)

    Nanocrystalline NdFeB magnets were prepared by spark plasma sintering (SPS) and SPS followed by HD using melt spun ribbons as the starting materials. The microstructure of SPSed and HDed magnets were analyzed. The effects of process including temperature and compression ratio on the microstructure and properties were investigated. High magnetic properties were obtained in anisotropic HDed magnets. The combination of Zn and Dy additions was successfully employed to improve the coercivity and thermal stability of the SPSed magnets. Open recoil loops were found in these magnets with Nd-rich composition and without soft magnetic phase for the first time. The relationship between the recoil loops and microstructure for SPS and HD NdFeB magnets were investigated. The investigations showed that the magnetic properties of SPS+HDed magnets are related to the extent of the aggregation of Nd-rich phase, which was formed during HD due to existence of porosity in SPSed precursor. Large local demagnetization fields induced by the Nd-rich phase aggregation leads to the open loops and significantly reduced the coercivity. By reducing the recoil loop openness, the magnetic properties of HDed NdFeB magnets were successfully improved. (author)

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

    International Nuclear Information System (INIS)

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

  19. Physical properties of hydrated tissue determined by surface interferometry of laser-induced thermoelastic deformation

    International Nuclear Information System (INIS)

    Knee meniscus is a hydrated tissue; it is a fibrocartilage of the knee joint composed primarily of water. We present results of interferometric surface monitoring by which we measure physical properties of human knee meniscal cartilage. The physical response of biological tissue to a short laser pulse is primarily thermomechanical. When the pulse is shorter than characteristic times (thermal diffusion time and acoustic relaxation time) stresses build and propagate as acoustic waves in the tissue. The tissue responds to the laser-induced stress by thermoelastic expansion. Solving the thermoelastic wave equation numerically predicts the correct laser-induced expansion. By comparing theory with experimental data, we can obtain the longitudinal speed of sound, the effective optical penetration depth and the Grueneisen coefficient. This study yields information about the laser-tissue interaction and determines properties of the meniscus samples that could be used as diagnostic parameters. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-09-15

    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)

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

    OpenAIRE

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

    2004-01-01

    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...

  2. Influence of substructure on mechanical properties of austenitic alloys deformed by warm rolling

    International Nuclear Information System (INIS)

    A connection between a substructure and mechanical properties of some iron base austenitic alloys, differing in carbon, and carbide-forming element contents and in stacking fault energies after warm rolling, is studied. It is shown that the maximum value of yield strength after cold hardening is achieved in the alloy with low stacking fault energy due to the formation of high density of thin twins

  3. Influence of substructure on mechanical properties of austenitic alloys deformed by warm rolling

    Energy Technology Data Exchange (ETDEWEB)

    Izotov, V.I.; Virakhovskij, Yu.G.; Marusenko, S.Ya. (Tsentral' nyj Nauchno-Issledovatel' skij Inst. Chernoj Metallurgii, Moscow (USSR). Inst. Metallovedeniya i Fiziki Metallov)

    1983-08-01

    A connection between a substructure and mechanical properties of some iron base austenitic alloys, differing in carbon, and carbide-forming element contents and in stacking fault energies after warm rolling, is studied. It is shown that the maximum value of yield strength after cold hardening is achieved in the alloy with low stacking fault energy due to the formation of high density of thin twins.

  4. Annealing behaviour and mechanical properties of severely deformed interstitial free steel

    International Nuclear Information System (INIS)

    Highlights: ? Microstructure and micro-texture evolution indicates continuous recrystallisation. ? HAGBs decrease from ?80 to ?40% due to texture clustering and orientation pinning. ? Characterisation of correlation between tensile and shear punch tests. ? Tensile behaviour evolves from stress drop to continuous yielding a work hardening. - Abstract: The evolution of microstructure, micro-texture and mechanical properties during isothermal annealing of an ultrafine grained interstitial free (IF) steel processed by Equal Channel Angular Pressing (ECAP) followed by 95% cold rolling (CR) was studied. Microstructure and micro-texture changes were characterised by Electron Back-Scattering Diffraction while mechanical properties were assessed by shear punch and uniaxial tensile testing. During annealing, homogeneous coarsening via continuous recrystallisation is accompanied by the retention of a sharp ?-fibre rolling texture and a decrease in area fraction of high angle grain boundaries from ?80% to ?40% due to texture clustering and orientation pinning. Failure during uniaxial tension occurred without post-necking elongation after CR. Upon annealing, an evolution from stress-drop soon after yielding to a return to continuous yielding and increased work hardening was observed. Good agreement is found between experimental and estimated strengths and total elongations derived from SPT and tensile data. Tensile characteristics and mechanical properties depend on both, grain size and area fraction of HAGBs.

  5. Annealing behaviour and mechanical properties of severely deformed interstitial free steel

    Energy Technology Data Exchange (ETDEWEB)

    Gazder, Azdiar A. [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, New South Wales 2522 (Australia); Hazra, Sujoy S., E-mail: sujoy.hazra@gmail.com [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, New South Wales 2522 (Australia); Pereloma, Elena V. [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, New South Wales 2522 (Australia)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer Microstructure and micro-texture evolution indicates continuous recrystallisation. Black-Right-Pointing-Pointer HAGBs decrease from {approx}80 to {approx}40% due to texture clustering and orientation pinning. Black-Right-Pointing-Pointer Characterisation of correlation between tensile and shear punch tests. Black-Right-Pointing-Pointer Tensile behaviour evolves from stress drop to continuous yielding a work hardening. - Abstract: The evolution of microstructure, micro-texture and mechanical properties during isothermal annealing of an ultrafine grained interstitial free (IF) steel processed by Equal Channel Angular Pressing (ECAP) followed by 95% cold rolling (CR) was studied. Microstructure and micro-texture changes were characterised by Electron Back-Scattering Diffraction while mechanical properties were assessed by shear punch and uniaxial tensile testing. During annealing, homogeneous coarsening via continuous recrystallisation is accompanied by the retention of a sharp {alpha}-fibre rolling texture and a decrease in area fraction of high angle grain boundaries from {approx}80% to {approx}40% due to texture clustering and orientation pinning. Failure during uniaxial tension occurred without post-necking elongation after CR. Upon annealing, an evolution from stress-drop soon after yielding to a return to continuous yielding and increased work hardening was observed. Good agreement is found between experimental and estimated strengths and total elongations derived from SPT and tensile data. Tensile characteristics and mechanical properties depend on both, grain size and area fraction of HAGBs.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-05-16

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

  7. Deformable Nanolaminate Optics

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-05-12

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

  8. 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)

  9. Structure and mechanical properties of an aluminum alloy 1570 subjected to severe plastic deformation by high-pressure torsion

    Science.gov (United States)

    Murashkin, M. Yu.; Kil'Mametov, A. R.; Valiev, R. Z.

    2008-07-01

    The effect of an ultrafine-grained (UFG) structure formed in an aluminum alloy 1570 using severe plastic deformation by high-pressure torsion (HPT) at room temperature and at temperatures of 100 and 200°C on the mechanical properties (strength and plasticity) has been investigated. The specific features of the UFG states obtained have been studied by transmission electron microscopy and X-ray diffraction analysis. The main regularities of changes in the structure characteristics of the alloy (the average grain size, size of coherent domains, magnitudes of microdeformations of the crystal lattice, dislocation density, and the lattice parameter) have been established depending on the temperature of the HPT treatment. The mechanical properties of the alloy after HPT have been estimated from the results of microhardness measurements and mechanical tests for tension. It has been established that after HPT performed at room temperature, the UFG alloy demonstrates an ultimately high level of strength (the microhardness, offset yield strength, and ultimate strength reach 2300, 905, and 950 MPa, respectively) and a marked plasticity (the relative elongation at fracture was 4.7%). The HPT treatment performed at higher temperatures insignificantly reduces the strength characteristics of the UFG material but leads to a substantial drop in its plasticity. This unusual mechanical behavior of the UFG alloy is discussed based on an analysis of the results of structural investigations.

  10. Appraising nuclear octupole moment contributions to the hyperfine structures in $^{211}$Fr

    CERN Document Server

    Sahoo, B K

    2015-01-01

    Hyperfine structures of $^{211}$Fr due to the interactions of magnetic dipole ($\\mu$), electric quadrupole ($Q$) and magnetic octupole ($\\Omega$) moments with the electrons are investigated using the relativistic coupled-cluster (RCC) theory with an approximation of singles, doubles and important valence triples excitations in the perturbative approach. Validity of our calculations are substantiated by comparing the results with their available experimental values. Its $Q$ value has also been elevated by combining the measured hyperfine structure constant of the $7p \\ ^2P_{3/2}$ state with our improved calculation. Considering the preliminary value of $\\Omega$ from the nuclear shell-model, its contributions to the hyperfine structures up to the $7d \\ ^2D_{5/2}$ low-lying states in $^{211}$Fr are estimated. Energy splittings of the hyperfine transitions in many states have been assessed to find out suitability to carry out their precise measurements so that $\\Omega$ of $^{211}$Fr can be inferred from them unam...

  11. Search for the two-phonon octupole vibrational state in 208Pb

    International Nuclear Information System (INIS)

    We have performed an experiment to search for the two-phonon octupole vibrational state in 208Pb. Thick targets of 208Pb, 209Bi, 58,64Ni, and 160Gd were bombarded with 1305 MeV beams of 208Pb supplied by the ATLAS accelerator facility at Argonne. Gamma rays were measured using the Argonne-Notre Dame BGO gamma ray facility, consisting of 12 Compton suppressed Ge detectors surrounding an array of 50 BGO scintillators. We have identified some 30 known ? rays from 208Pb in coincidence spectra gated on low-lying transitions in 208Pb. In addition, after unfolding these spectra for Compton response, we observe broad coincident structures in the energy region expected for the decay of 2-phonon states. Furthermore, we have confirmed the placement of a previously observed 2485 keV ? ray in 207Pb and find no evidence consistent with the placement of this line in 208Pb. (orig.)

  12. Experiment and theory of a drift wave in the levitated octupole

    International Nuclear Information System (INIS)

    A very coherent 30 kHz drift wave is observed in the Levitated Toroidal Octupole at the University of Wisconsin - Madison. The density and floating potential fluctuations have a well-defined spatial structure in the poloidal magnetic field. Radially the wave has a standing wave structure with amplitude peaked in regions of locally bad magnetic curvature. Poloidally the wave has a standing wave structure with odd symmetry; nodes are located in the regions of locally good magnetic curvature. The wave propagates toroidally in the electron diamagnetic drift direction with a wavelength of 20 centimeters. No changes occur in the wave structure as the plasma is varied over three orders of magnitude in density and beta

  13. Experimental investigation of plasma resistivity and ohmic heating in the octupole with toroidal magnetic field

    International Nuclear Information System (INIS)

    Plasma resistivity parallel to the magnetic field in the Wisconsin small octupole with toroidal magnetic field is investigated experimentally. A method is developed to use the flux surface constant, current density divided by magnetic field magnitude, to make possible the measurement of the average resistivity on a flux surface. An heuristic model for resistivity based on the neoclassical effects of Coulomb collisions and particle trapping in the magnetic mirrors is modified to also include neutral collisions and the reduction, caused by the parallel electric field, of mirror trapping. The scaling of resistivity with plasma and field parameters in this model is determined by the collisionality of the plasma with respect to the frequency of an average particle's encounters with the magnetic field maxima. The regimes are collisional, collisionless and intermediate or plateau. The local ohmic heating rate and plasma current density and their integrals over the experiment's volume are calculated

  14. Gyromagnetic ratios and octupole collectivity in the structure of the 90-96Zr isotopes

    International Nuclear Information System (INIS)

    Shell model calculations have been performed for low-excitation states in the Zr isotopes between 90Zr and 96Zr with an emphasis on the g factors and electromagnetic decay rates for the lowest 2+ and 3- states. Overall the 2+ states are reasonably well described. In contrast, the 3- states present a puzzle because the measured g factors imply a single-particle configuration whereas the experimental E3 transition rates imply collective structures that cannot be explained by shell model calculations. A consistent description of the 3- states in 90Zr and 96Zr is sought in terms of coupling between the single-particle structure and a collective octupole vibration

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

    Directory of Open Access Journals (Sweden)

    W. Ozgowicz

    2008-07-01

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

  16. Microstructural evolution and mechanical properties of cryomilled nanograined near Al-5083 alloy following deformation processing

    Science.gov (United States)

    Kaisar, Khan Hasib

    Nanocrystalline Al-Mg alloys are being considered for light weight transportation applications because they possess significantly higher strength than the conventional coarse grained alloys. Failure strengths higher than 1000 MPa have been reported for Al-5083 alloy at New Mexico Tech, which are almost double the strength of commercial precipitation strengthened Al-alloys. Unfortunately, the ductility tends to exhibit inverse relationship to strength and therefore there is a need to find ways to increase the ductility while maintaining high strength. In this work, we utilize a near Al-5083 alloy that was cryomilled for 24 hours in liquid nitrogen environment and consolidated by vacuum hot-pressing. The as-atomized Al-Mg powder was especially fabricated to minimize undesired impurity content to prevent premature fracture from intermetallic particles. It turned out that the final composition was slightly lower in Mn and Mg content and so the alloy is better designated as a near Al-5083 alloy. The as-vacuum hot pressed material had poor ductility because of inadequate prior-particle bonding, and therefore was subjected to deformation processing using low strain-rate extrusion at elevated temperatures. Both the strain-rate and temperature of extrusion were varied in an effort to obtain a good combination of tensile strength and ductility. In addition, the samples were annealed following extrusion in order to reduce residual stresses. The microstructure of extruded samples were characterized using a combination of electron microscope and X-ray diffraction techniques, and revealed a multi-scale morphology that could be binned into three different sizes of grains: i) those less than 100 nm that were analyzed using the X-ray based Williamson-Hall technique and transmission electron microscopy (TEM), ii) grain sizes in the 100-300 nm regime that were best revealed using TEM and scanning electron microscope (SEM) based electron-backscatter diffraction (EBSD) techniques, and, iii) elongated larger grains with lengths in the range 3 to 7 ?m that were observed using EBSD. Room temperature tensile tests with small tensile samples indicated that ultimate strengths in the range 740-760 MPa and elongation to failure better than 2.5%. These data could be produced reproducibly following extrusion at 400 C at an average strain rate of 0.05/sec, and fractography revealed a rough topography with large pull out regions that consisted of typical ductile dimple void growth at the 200-500 nm scale, while in other regions the dimples were very shallow that would suggest failure with little energy loss likely in regions of nanograins less than 100 nm. The combination of strength and ductility in the material are some of the best that have been reported for Al-5083 alloys, and likely a result of the multi-scale microstructure resulting from processing through the cryomilling and extrusion plus annealing procedures.

  17. Inferring strength and deformation properties of hot mix asphalt layers from the GPR signal: recent advances

    Science.gov (United States)

    Tosti, Fabio; Benedetto, Andrea; Bianchini Ciampoli, Luca; Adabi, Saba; Pajewski, Lara

    2015-04-01

    The great flexibility of ground-penetrating radar has led to consider worldwide this instrument as an effective and efficient geophysical tool in several fields of application. As far as pavement engineering is concerned, ground-penetrating radar is employed in a wide range of applications, including physical and geometrical evaluation of road pavements. Conversely, the mechanical characterization of pavements is generally inferred through traditional (e.g., plate bearing test method) or advanced non-destructive techniques (e.g., falling weight deflectometer). Nevertheless, measurements performed using these methods, inevitably turn out to be both much more time-consuming and low-significant whether compared with ground-penetrating radar's potentials. In such a framework, a mechanical evaluation directly coming from electromagnetic inspections could represent a real breakthrough in the field of road assets management. With this purpose, a ground-penetrating radar system with 600 MHz and 1600 MHz center frequencies of investigation and ground-coupled antennas was employed to survey a 4m×30m flexible pavement test site. The test area was marked by a regular grid mesh of 836 nodes, respectively spaced by a distance of 0.40 m alongside the horizontal and vertical axes. At each node, the elastic modulus was measured using a light falling weight deflectometer. Data processing has provided to reconstruct a 3-D matrix of amplitudes for the surveyed area, considering a depth of around 300 mm, in accord to the influence domain of the light falling weight deflectometer. On the other hand, deflectometric data were employed for both calibration and validation of a semi-empirical model by relating the amplitude of signal reflections through the media along fixed depths within the depth domain considered, and the Young's modulus of the pavement at the evaluated point. This statistically-based model is aimed at continuously taking into account alongside the depth of investigation, of both the different strength provision of each layer composing the hot mix asphalt pavement structure, and of the attenuation occurring to electromagnetic waves during their in-depth propagation. Promising results are achieved by matching modelled and measured elastic modulus data. This continuous statistically-based model enables to consider the whole set of information related to each single depth, in order to provide a more comprehensive prediction of the strength and deformation behavior of such a complex multi-layered medium. Amongst some further developments to be tackled in the near future, a model improvement could be reached through laboratory activities under controlled conditions and by adopting several frequency bandwidths suited for purposes. In addition, the perspective to compare electromagnetic data with mechanical measurements retrieved continuously, i.e., by means of specifically equipped lorries, could pave the way to considerable enhancements in this field of research. Acknowledgements - This work has benefited from networking activities carried out within the EU funded COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar".

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

    Science.gov (United States)

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

    2008-05-01

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

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

    OpenAIRE

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

    2010-01-01

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

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

    Science.gov (United States)

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

    2010-12-01

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

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

    Directory of Open Access Journals (Sweden)

    Jab?o?ska M.B.

    2014-10-01

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

  2. Deformation and Fracture Properties in Neutron Irradiated Pure Mo and Mo Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Byun, Thak Sang [ORNL; Li, Meimei [ORNL; Cockeram, Brian V [Bechtel-Bettis, Inc.; Snead, Lance Lewis [ORNL

    2008-01-01

    The effect of neutron irradiation on the mechanical properties of select molybdenum materials, pure low carbon arc-cast (LCAC) Mo, Mo-0.5% Ti-0.1% Zr (TZM) alloy, and oxide dispersion-strengthened (ODS) Mo alloy, was characterized by analyzing the temperature dependence of mechanical properties. This study assembles the tensile test and analysis data obtained through multiple series of irradiation and post-irradiation experiments. Tensile specimens in stress-relieved conditions with longitudinal (LSR) and transverse (TSR) directions were irradiated in high flux isotope reactor (HFIR) at temperatures ranging 270 to 1100oC to 0.6 -13.1 dpa. Also, the recrystallized LCAC Mo specimens in the longitudinal direction (LR) were also irradiated up to 0.28 dpa at ~80oC. Tensile tests were performed at temperatures ranging from -194 oC to 1400oC. Analysis results indicate that the irradiation at temperatures below 700oC increased strength significantly, up to 170%, while the increase of yield stress by irradiations at higher temperature was not significant. The plastic instability stress was strongly dependent on test temperature but was nearly independent of irradiation dose and temperature. The true fracture stress was dependent on test temperature to a lesser degree than was the yield stress and plastic instability stress. It was also slightly impacted by irradiation, depending on both irradiation and test temperatures. Brittle fracture often occurred in the LSR specimens tested at room temperature or lower after low temperature irradiation, while it was observed in many irradiated TSR specimens over the whole test temperature range. The ODS-LSR specimens showed the highest resistance to irradiation embrittlement due to relatively higher fracture stress. The critical temperature for shear failure (CTSF) was defined and evaluated for the materials, and the CTSF values were compared with the ductile to brittle transition temperatures (DBTT) based on ductility data.

  3. 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

  4. Effect of plastic deformation on the electrophysical properties and structure of YBa2Cu3O y ceramics subjected to low-temperature treatment

    Science.gov (United States)

    Bobylev, I. B.; Zyuzeva, N. A.; Degtyarev, M. V.; Pilyugin, V. P.

    2015-12-01

    The electrophysical properties and structure of HTSC YBa2Cu3O y compound (123) subjected to plastic deformation by shear under a pressure of 1.7 GPa have been studied. After deformation, the electrophysical properties of samples prepared using the traditional ceramic technology were found to deteriorate. Subsequent annealing at 930°C cannot restore the critical current density ( j c) in low magnetic fields to initial magnitudes; however, in magnetic fields of more than 0.1 T, the j c magnitude increases compared to that for the starting state. The deformation of 123 ceramics treated at 200°C in a humid atmosphere that has undergone phase transformation into the 124 tetragonal phase allows its structure and electrophysical properties to be restored. In this case, the reverse transformation of phase 124 into 123, which is accompanied by the recrystallization of the material, takes place. The combination of low-temperature treatment and high shearing deformation leads to the appearance of texture and an increase of j c, in particular in high magnetic fields.

  5. 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 SiO2 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 SiO2 will not be able to produce a brittle behaviour of the buffer mass even after thousands of years

  6. Layer-specific residual deformations and uniaxial and biaxial mechanical properties of thoracic porcine aorta.

    Science.gov (United States)

    Peña, Juan A; Martínez, Miguel A; Peña, Estefanía

    2015-10-01

    In this paper we hypothesize that the layer-separated residual stresses and mechanical properties of layer-separated thoracic aorta arteries may be dependent on arterial location of the vessel. To demonstrate any possible position differences, we measured the axial pre-stretch and opening angle and performed uniaxial and biaxial tests under physiological loads to study the mechanical behavior of both intact and layer-separated porcine aortic samples taken from thoracic region. In addition, we also provided constitutive parameters for each layer that can be used by biomedical engineers for investigating better therapies and developing artery-specific devices. We found that the opening angle for whole artery and adventitia layer are smaller and intima greater for proximal segments than for the distal thoracic ones. For the axial pre-stretch, our results showed significant increased values of the stretch ratios with location. We found that lower thoracic samples are stiffer than upper ones with the most important differences corresponding to those between the proximal and distal behaviors in the circumferential direction. The anisotropy represented by the different circumferential and longitudinal response is more remarkable in lower thoracic aorta. Finally, adventitia and intima samples present a tendency to be stiffer and more isotropic than the corresponding media samples in both directions for upper thoracic aorta and to be more anisotropic for lower thoracic aorta. PMID:26103440

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

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

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

    Science.gov (United States)

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

    2014-06-01

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

  9. Mechanical properties and microstructure of 6061 aluminum alloy severely deformed by ARB process and subsequently aged at low temperatures

    Science.gov (United States)

    Terada, Daisuke; Kaneda, Yoma; Horita, Zenji; Matsuda, Kenji; Hirosawa, Shoichi; Tsuji, Nobuhiro

    2014-08-01

    In order to clarify the aging behavior in ultrafine grained (UFG) Al alloys, a commercial Al-Mg-Si alloy was severely deformed by accumulative roll-bonding (ARB) process and subsequently aged at 100°C or 170°C. The age-hardening behavior and microstructure change during aging were investigated. At 170 °C, age-hardening was observed in solution treated (ST) specimens, but solution-treated and ARB-processed specimens were not hardened by aging. On the other hand, the hardness of the both ST specimen and ARB-processed specimen increased by aging at 100°C. From TEM observation, it was found that the ARB- processed specimen had an ultrafine lamellar boundary structure and the structure was kept during aging at 170°C and 100°C. In the ST specimen aged at 170°C, fine precipitates were observed within coarse grains. In the specimen ARB-processed and subsequently aged at 170°C, coarser precipitates were observed within ultrafine grains and on grain boundaries. It was considered that the reason why the hardness of the specimens ARB-processed and subsequently aged did not increase was coarsening of precipitates. In the specimens aged at 100°C, obvious precipitates were not observed, but clusters Mg and Si seemed to form during the aging, leading to the increase in the hardness of the specimen. From the results, it was suggested that aging at low temperatures could improve mechanical properties of Al alloys through combining grain refinement and precipitation hardening.

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

    Science.gov (United States)

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

    2014-05-01

    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.

  11. Finite Element Analysis of Deformation Due to Ball Indentation and Evaluation of Tensile Properties of Tempered P92 Steel

    Science.gov (United States)

    Barbadikar, Dipika R.; Ballal, A. R.; Peshwe, D. R.; Mathew, M. D.

    2015-08-01

    Ball indentation (BI) technique has been effectively used to evaluate the tensile properties with minimal volume of material. In the present investigation, BI test carried out on P92 steel (9Cr-0.5Mo-1.8W), using 0.76 mm diameter silicon nitride ball indenter was modeled using finite element (FE) method and analyzed. The effect of test temperature [300 K and 923 K (27 °C and 650 °C)], tempering temperature [1013 K, 1033 K, and 1053 K (740 °C, 760 °C, and 780 °C)], and coefficient of friction of steel (0.0 to 0.5) on the tensile strength and material pile-up was investigated. The stress and strain distributions underneath the indenter and along the top elements of the model have been studied to understand the deformation behavior. The tensile strength was found to decrease with increase in tempering and test temperatures. The increased pile-up around the indentation was attributed to the decrease in strain hardening exponent ( n) with increase in the test temperature. The pile-up height determined from profilometry studies and FE analysis as well as the load depth curve from BI and FE analysis was in agreement. The maximum strain location below the indentation changes with the test temperature. Stress-strain curves obtained by conventional tensile, BI test, and representative stress-strain concepts of FE model were found exactly matching.

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

    Science.gov (United States)

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

    2007-05-01

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

  13. 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

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

    Science.gov (United States)

    Kovác, P.; Hušek, I.; Pachla, W.; Kulczyk, M.

    2007-07-01

    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 µm down to 19 µm 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 µm. 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.

  15. 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.

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

    International Nuclear Information System (INIS)

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

  17. 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.)

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

    OpenAIRE

    Serizawa, Yasuyoshi; Matsuo, Masayuki

    2008-01-01

    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...

  19. Effect of hot deformation on texture and magnetic properties of Sm-Co and Pr-Co alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gabay, A.M., E-mail: gabay@physics.udel.edu [Department of Physics and Astronomy, University of Delaware, 217 Sharp Lab, Newark, DE 19716 (United States); Li, W.F.; Hadjipanayis, G.C. [Department of Physics and Astronomy, University of Delaware, 217 Sharp Lab, Newark, DE 19716 (United States)

    2011-10-15

    Nanocrystalline PrCo{sub 5}, SmCo{sub 5} and Sm{sub 2}(Co,Fe,Mn){sub 17} alloys were subjected to a high-degree plastic deformation at 950 deg. C with the height reduction ranging from 70% to 95%. With increasing degree of deformation, the PrCo{sub 5} and SmCo{sub 5} magnets showed improvement of the deformation-induced [0 0 1] texture. The PrCo{sub 5} alloys, known to develop a superior texture at the lower degrees of deformation, showed only modest improvement and their magnetic performance was undermined by a low coercivity. The SmCo{sub 5} alloys had their texture markedly enhanced and, after height reduction by 94.5%, they exhibited a remanence of 8.6 kG, maximum energy product of 18 MGOe and an intrinsic coercivity of 22.8 kOe. No induced texture was found in the alloys based on the Sm{sub 2}Co{sub 17} structure. The microstructures of the hot-deformed alloys were studied with a transmission electron microscopy, and possible mechanisms of the texture development in the RCo{sub 5} alloys (R=Pr, Sm) are briefly discussed. - Highlights: > The effects high-degree deformation were compared for three rare earth-cobalt alloys. > SmCo{sub 5} alloys benefit most from deformation exceeding 90%. > High-degree deformation slightly improves texture of PrCo{sub 5} but damages the coercivity. > Even the high-degree deformation does not induce texture in alloys based on Sm{sub 2}Co{sub 17}.

  20. 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

  1. 'Windswept deformity'.

    OpenAIRE

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

    1983-01-01

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Louis, L.

    2003-10-15

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

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

    Directory of Open Access Journals (Sweden)

    W. Ozgowicz

    2010-05-01

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

  4. THE EFFECT OF SUPERPLASTIC DEFORMATION ON THE TENSILE AND FATIGUE PROPERTIES OF Al-Li (8090) ALLOY

    OpenAIRE

    Mcdarmaid, D.; Shakesheff, A.

    1987-01-01

    Superplastic deformation of the new generation of aerospace aluminium-lithium alloys has generated considerable interest in the aerospace industry not only with the potential savings in component weight and manufacturing costs but also for development of novel designs. Even though many papers have addressed the superplastic deformation characteristics of these alloys it is essential for their exploitation to determine and to understand the effect of the forming process on their mechanical pro...

  5. Influence of Heat Treatment Conditions on Microstructure and Mechanical Properties of Austempered Ductile Iron After Dynamic Deformation Test

    Directory of Open Access Journals (Sweden)

    Myszka D.

    2014-10-01

    Full Text Available In this article, an attempt was made to determine the effect of dynamic load on the austempered ductile iron resistance obtained under different conditions of heat treatment. Tests were carried out on six types of cylindrical ductile iron samples austempered at 320, 370 and 400oC for 30 and 180 minutes. For each type of material, two samples were collected. As a next step in the investigations, the samples were subjected to a Taylor impact test. The samples after striking a non-deformable, rigid target were deformed on their front face. After Taylor test, a series of material tests was performed on these samples, noting a significant increase of hardness in the deformed part. This was particularly well visible in the ductile iron isothermally quenched at higher temperatures of 370 and 400oC. Inthezone of sample deformation, an increase in the content of ferromagnetic phase was also reported, thus indicating the occurrence of martensitic transformation in the microstructure containing mechanically unstable austenite. A significant amount of deformed graphite was also observed, which was a symptom of the deformation process taking place in samples. The ductile iron was characterized by high toughness and high resistance to the effect of dynamic loads, especially as regards the grade treated at a temperature of 370oC.

  6. Effect of Heat Treatment on the Microstructure and Properties of Deformation-Processed Cu-7Cr In Situ Composites

    Science.gov (United States)

    Liu, Keming; Jiang, Zhengyi; Zhou, Haitao; Lu, Deping; Atrens, Andrej; Yang, Yanling

    2015-11-01

    The effect of heat treatment on the microstructure, electrical conductivity, and tensile strength of deformation-processed Cu-7Cr in situ composites produced by thermo-mechanical processing was investigated. The Cr fibers in the Cu-7Cr in situ composite underwent coarsening, break-up, and spheroidization after exposure to elevated temperatures. The conductivity and tensile strength of the in situ composite first increased with increasing isochronal heat treatment temperature, reached a peak value, and decreased at higher temperatures. The isothermal heat treatment temperature was determined to be 625 °C. The Z ( Z is an optimization parameter to evaluate the service performance of deformation-processed Cu-based in situ composites) value of the deformation-processed Cu-7Cr in situ composite, at ? = 7 ( ? is a cumulative cold deformation strain) after the heat treatment at 625 °C for 1 h, reached the peak value of 3.46 × 107 MPa2 % International Annealed Copper Standard (IACS). The isochronal heat treatment time was determined to be 1 h. The following combination of conductivity and tensile strength of the deformation-processed Cu-7Cr in situ composite with a cumulative cold deformation strain of eight after isochronal aging treatments for 1 h could be attained respectively as (i) 76.0% IACS and 889 MPa; (ii) 76.8% IACS and 876 MPa; or (iii) 77.5% IACS and 779 MPa.

  7. New results for the missing quantum numbers labelling the quadrupole and octupole boson basis

    International Nuclear Information System (INIS)

    The many 2k-pole boson states, |Nkvk?kIkMk) with k = 2, 3, realize the irreducible representation (IR) for the group reduction chains SU(2k + 1) R2k+1 R3 R2. They have been analytically studied and widely used for the description of nuclear systems. However, no analytical expression for the degeneracy d(k)v(I) of the R2k+1 IR, determined by the reduction R2k+1 R3, with k = 2, 3 is available. Thus, the number of distinct values taken by ?k has been so far obtained by solving some complex equations. Here we derive analytical expressions for the degeneracy d(k)v(I) (k = 2, 3), characterizing the octupole and quadrupole boson states, respectively. The merit of this work consists of the fact that it completes the analytical expressions for the 2k-pole boson basis for k = 2, 3. The general case of R2l+1 IR representation degeneracy is also presented and a compact analytical expression for d(l)v(I) is derived

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-08-01

    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.

  9. Search for the two-phonon octupole vibrational state in 208Pb

    International Nuclear Information System (INIS)

    We performed an experiment to search for the two-phonon octupole vibrational state in 208Pb. Thick targets of 208Pb, 209Bi, 58,64Ni, and 160Gd were bombarded with 1305 MeV beams of were bombard 208Pb 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 208Pb in the spectra gated by the 5- ? 3- and 3- ? 0+ transitions in 208Pb. 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 207Pb and find no evidence consistent with the placement of this line in 208Pb. 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 208Pb, 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 208Pb target

  10. Low frequency turbulence, particle and heat transport in the Wisconsin levitated octupole

    International Nuclear Information System (INIS)

    Low frequency turbulence in the drift frequency range and its relation to the observed particle transport in the Wisconsin Levitated Octupole has been studied with a microwave scattering apparatus. The experimental parameters were T/sub e/ approx. T/sub i/ 13 cm-3, 200 G < B/sub p-average/ < 1.25 kG. The effect of shear on the transport was studied by the addition of a small toroidal field. By matching experimentally measured density profiles to those given by numerical solutions of the transport equations, diffusion coefficients were obtained. Time dependent density fluctuation spectra were measured with an 8 mm microwave scattering diagnostic to correlate the drift wave portion of the spectrum with the observed diffusion. The density fluctuation spectrum of low frequency (1 kHz < ? < 6 MHz) turbulence was measured for several values of perpendicular wavenumber, k/sub perpendicular to/. Electron heat transport was studied by fitting experimentally measured electron temperature profiles to those predicted by numerical solutions of electron energy transport equation

  11. The decay of quadrupole-octupole $1^-$ states in $^{40}$Ca and $^{140}$Ce

    CERN Document Server

    Derya, V; Aumann, T; Bhike, M; Endres, J; Gooden, M; Hennig, A; Isaak, J; Lenske, H; Löher, B; Pietralla, N; Savran, D; Tornow, W; Werner, V; Zilges, A

    2016-01-01

    Background: Two-phonon excitations originating from the coupling of two collective one-phonon states are of great interest in nuclear structure physics. One possibility to generate low-lying $E1$ excitations is the coupling of quadrupole and octupole phonons. Purpose: In this work, the $\\gamma$-decay behavior of candidates for the $(2_1^+\\otimes 3_1^-)_{1^-}$ state in the doubly-magic nucleus $^{40}$Ca and in the heavier and semi-magic nucleus $^{140}$Ce is investigated. Methods: $(\\vec{\\gamma},\\gamma')$ experiments have been carried out at the High Intensity $\\gamma$-ray Source (HI${\\gamma}$S) facility in combination with the high-efficiency $\\gamma$-ray spectroscopy setup $\\gamma^3$ consisting of HPGe and LaBr$_3$ detectors. The setup enables the acquisition of $\\gamma$-$\\gamma$ coincidence data and, hence, the detection of direct decay paths. Results: In addition to the known ground-state decays, for $^{40}$Ca the decay into the $3^-_1$ state was observed, while for $^{140}$Ce the direct decays into the $2...

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

    International Nuclear Information System (INIS)

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

  13. Suppression of quadrupole and octupole modes in red giants observed by Kepler

    CERN Document Server

    Stello, D; Fuller, J; Garcia, R A; Huber, D

    2016-01-01

    The asteroseismology of red giant stars has continued to yield surprises since the onset of high-precision photometry from space-based observations. An exciting new theoretical result shows that the previously observed suppression of dipole oscillation modes in red giants can be used to detect strong magnetic fields in the stellar cores. A fundamental facet of the theory is that nearly all the mode energy leaking into the core is trapped by the magnetic greenhouse effect. This results in clear predictions for how the mode visibility changes as a star evolves up the red giant branch, and how that depends on stellar mass, spherical degree, and mode lifetime. Here, we investigate the validity of these predictions with a focus on the visibility of different spherical degrees. We find that mode suppression weakens for higher degree modes with an average reduction in the quadrupole mode visibility of up to 49% for the least evolved stars in our sample, and no detectable suppression of octupole modes, in agreement w...

  14. 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.

  15. Deformed shell model studies of spectroscopic properties of 64Zn and 64Ni and the positron double beta decay of 64Zn

    Indian Academy of Sciences (India)

    R Sahu; V K B Kota

    2014-04-01

    The spectroscopic properties of 64Zn and 64Ni are calculated within the framework of the deformed shell model (DSM) based on Hartree–Fock states. GXPF1A interaction in 1 $f_{7/2}$, 2$p_{3/2}$, 1$f_{5/2}$ and 2$p_{1/2}$ space with 40Ca as the core is employed. After ensuring that DSM gives good description of the spectroscopic properties of low-lying levels in these two nuclei considered, nuclear transition matrix elements (NTME) for the neutrinoless positron double beta decay (0$\

  16. Effect of hot deformation on texture and magnetic properties of Sm-Co and Pr-Co alloys

    Science.gov (United States)

    Gabay, A. M.; Li, W. F.; Hadjipanayis, G. C.

    2011-10-01

    Nanocrystalline PrCo 5, SmCo 5 and Sm 2(Co,Fe,Mn) 17 alloys were subjected to a high-degree plastic deformation at 950 °C with the height reduction ranging from 70% to 95%. With increasing degree of deformation, the PrCo 5 and SmCo 5 magnets showed improvement of the deformation-induced [0 0 1] texture. The PrCo 5 alloys, known to develop a superior texture at the lower degrees of deformation, showed only modest improvement and their magnetic performance was undermined by a low coercivity. The SmCo 5 alloys had their texture markedly enhanced and, after height reduction by 94.5%, they exhibited a remanence of 8.6 kG, maximum energy product of 18 MGOe and an intrinsic coercivity of 22.8 kOe. No induced texture was found in the alloys based on the Sm 2Co 17 structure. The microstructures of the hot-deformed alloys were studied with a transmission electron microscopy, and possible mechanisms of the texture development in the RCo 5 alloys (R=Pr, Sm) are briefly discussed.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-01

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

  18. Influence of disorder and deformation on the optical properties of a two-dimensional photonic crystal waveguide

    International Nuclear Information System (INIS)

    We investigate the effect of disorder and mechanical deformation on a two-dimensional photonic crystal waveguide. The dispersion characteristics and transmittance of the waveguide are studied using the finite element method. Results show that the geometric change of the dielectric material perpendicular to the light propagation direction has a larger influence on the waveguide characteristics than that parallel to the light propagation direction. Mechanical deformation has an obvious influence on the performance of the waveguide. In particular, longitudinal deformed structure exhibits distinct optical characteristics from the ideal one. Studies on this work will provide useful guideline to the fabrication and practical applications based on photonic crystal waveguides. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

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

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.

  20. 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

  1. The Contribution of Plastic Deformations to the Adhesion Properties of Polymer-Polymer Contacts Studied with the Surface Force Apparatus.

    Science.gov (United States)

    Heuberger, Manfred; Luengo, Gustavo; Israelachvili, Jacob

    1996-03-01

    The energy dissipated in a loading-unloading process of a polymer-polymer contact is commonly referred to as adhesion hysteresis. Adhesion hysteresis contains contributions from different sources one of which is plastic deformation. We have studied in dry air the plastic deformation of two initially curved surfaces of Poly(Buthyl-Methacrylate) (PBMA) which has itUs Tg close to room temperature. Using the Surface Force Apparatus we have observed plastic deformations including the formation of a polymer-meniscus exhibiting cavitation-like effects on separation. The results are compared to the case of Poly(Methyl-Methacrylate) (PMMA) which is well below itUs Tg at room temperature.

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

    Science.gov (United States)

    Robledo, A.; Moyano, L. G.

    2008-03-01

    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.

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

    Directory of Open Access Journals (Sweden)

    S. Choudhary

    2011-01-01

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

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

    Science.gov (United States)

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

    2010-07-01

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

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-02-15

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

  8. Effect of Material Ion Exchanges on the Mechanical Stiffness Properties and Shear Deformation of Hydrated Cement Material Chemistry Structure C-S-H Jennite -- A Computational Modeling Study

    Science.gov (United States)

    Adebiyi, Babatunde Mattew

    Material properties and performance are governed by material molecular chemistry structures and molecular level interactions. Methods to understand relationships between the material properties and performance and their correlation to the molecular level chemistry and morphology, and thus find ways of manipulating and adjusting matters at the atomistic level in order to improve material performance, are required. A computational material modeling methodology is investigated and demonstrated for a key cement hydrated component material chemistry structure of Calcium-Silicate-Hydrate (C-S-H) Jennite in this work. The effect of material ion exchanges on the mechanical stiffness properties and shear deformation behavior of hydrated cement material chemistry structure of Calcium Silicate Hydrate (C-S-H) Jennite was studied. Calcium ions were replaced with Magnesium ions in Jennite structure of the C-S-H gel. Different level of substitution of the ions was used. The traditional Jennite structure was obtained from the American Mineralogist Crystal Structure Database and super cells of the structures were created using a Molecular Dynamics Analyzer and Visualizer Material Studio. Molecular dynamics parameters used in the modeling analysis were determined by carrying out initial dynamic studies. 64 unit cell of C-S-H Jennite was used in material modeling analysis studies based on convergence results obtained from the elastic modulus and total energies. NVT forcite dynamics using COMPASS force field based on 200 ps dynamics time was used to determine mechanical modulus of the traditional C-S-H gel and the Magnesium ion modified structures. NVT Discover dynamics using COMPASS forcefield was used in the material modeling studies to investigate the influence of ionic exchange on the shear deformation of the associated material chemistry structures. A prior established quasi-static deformation method to emulate shear deformation of C-S-H material chemistry structure that is based on a triclinic crystal structure was used, by deforming the triclinic crystal structure at 0.2 degree per time step for 75 steps of deformation. It was observed that there is a decrease in the total energies of the systems as the percentage of magnesium ion increases in the C-S-H Jennite molecular structure systems. Investigation of effect of ion exchange on the elastic modulus shows that the elastic stiffness modulus tends to decrease as the amount of Mg in the systems increases, using either COMPASS or universal force field. On the other hand, shear moduli obtained after deforming the structures computed from the stress-strain curve obtained from material modeling increases as the amount of Mg increases in the system. The present investigations also showed that ultimate shear stress obtained from predicted shear stress---strain also increases with amount of Mg in the chemistry structure. Present study clearly demonstrates that computational material modeling following molecular dynamics analysis methodology is an effective way to predict and understand the effective material chemistry and additive changes on the stiffness and deformation characteristics in cementitious materials, and the results suggest that this method can be extended to other materials.

  9. A Comparison of Two Magnetic Ultra-Cold Neutron Trapping Concepts Using a Halbach-Octupole Array

    Science.gov (United States)

    Leung, K.; Ivanov, S.; Martin, F.; Rosenau, F.; Simson, M.; Zimmer, O.

    2014-03-01

    This paper describes a new magnetic trap for ultra-cold neutrons (UCNs) made from a 1.2m long Halbach-octupole array of permanent magnets with an inner bore radius of 47mm combined with an assembly of superconducting end coils and bias field solenoid. The use of the trap in a vertical, magneto-gravitational and a horizontal setup are compared in terms of the effective volume and ability to control key systematic effects that need to be addressed in high precision neutron lifetime measurements.

  10. A comparison of two magnetic ultra-cold neutron trapping concepts using a Halbach-octupole array

    CERN Document Server

    Leung, K; Martin, F; Rosenau, F; Simson, M; Zimmer, O

    2015-01-01

    This paper describes a new magnetic trap for ultra-cold neutrons (UCNs) made from a 1.2 m long Halbach-octupole array of permanent magnets with an inner bore radius of 47 mm combined with an assembly of superconducting end coils and bias field solenoid. The use of the trap in a vertical, magneto-gravitational and a horizontal setup are compared in terms of the effective volume and ability to control key systematic effects that need to be addressed in high precision neutron lifetime measurements.

  11. Interference between selected dipoles and octupoles in the optical second-harmonic generation from spherical gold nanoparticles.

    Science.gov (United States)

    Butet, J; Bachelier, G; Russier-Antoine, I; Jonin, C; Benichou, E; Brevet, P-F

    2010-08-13

    Optical second-harmonic generation from gold nanoparticles is investigated both experimentally and theoretically. The contribution of octupoles is reported for the first time in the second-harmonic emission pattern, by using an harmonic polarization in the scattering plane. The experimental results presented here for particle sizes up to 100 nm are in excellent agreement with finite element method simulations involving the normal surface term only in the nonlinear polarization source. In addition, analytical calculations based on nonlinear Mie scattering theory clearly evidence the constructive and destructive interferences occurring between the dipolar and octupolar responses selected with this polarization configuration. PMID:20868074

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

    CERN Multimedia

    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

    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.

  13. Is nucleon deformed?

    International Nuclear Information System (INIS)

    The surprising answer to this question Is nucleon deformed? is : Yes. The evidence comes from a study of the quark model of the single nucleon and when it is found in a nucleus. It turns out that many of the long standing problems of the Naive Quark Model are taken care of if the nucleon is assumed to be deformed. Only one value of the parameter PD ?1/4 (which specifies deformation) fits gA (the axial vector coupling constant) for all the semileptonic decay of baryons, the F/D ratio, the pion-nucleon-delta coupling constant fsub(?N?), the double delta coupling constant1 fsub(???), the Ml transition moment ??N and g1p the spin structure function of proton2. All this gives strong hint that both neutron and proton are deformed. It is important to look for further signatures of this deformation. When this deformed nucleon finds itself in a nuclear medium its deformation decreases. So much that in a heavy nucleus the nucleons are actually spherical. We look into the Gamow-Teller strengths, magnetic moments and magnetic transition strengths in nuclei to study this property. (author). 15 refs

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-01

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

  15. Effect of heat treatment on the structural and phase transformations and mechanical properties of TiNi alloy subjected to severe plastic deformation by torsion

    Science.gov (United States)

    Kuranova, N. N.; Gunderov, D. V.; Uksusnikov, A. N.; Luk'yanov, A. V.; Yurchenko, L. I.; Prokof'ev, E. A.; Pushin, V. G.; Valiev, R. Z.

    2009-12-01

    Effect of annealing on the structural and phase transformations and mechanical properties of large-size samples of the Ti49.4Ni50.6 alloy preliminary subjected to severe plastic deformation by torsion under a high pressure (HPT) is studied. The study was performed by transmission and scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction, and measurements of mechanical properties. The annealing was found to result in the nanocrystallization of initial samples amorphized by HPT. In this alloy, the high-strength uniform nanostructured state is formed the size of nanocrystalline grains of which and the mechanical properties depend on the temperature and time of annealing.

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

    Directory of Open Access Journals (Sweden)

    Shao-Yi Lin

    2013-12-01

    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.

  17. Elastic Deformations in 2D van der waals Heterostructures and their Impact on Optoelectronic Properties: Predictions from a Multiscale Computational Approach

    Science.gov (United States)

    Kumar, Hemant; Er, Dequan; Dong, Liang; Li, Junwen; Shenoy, Vivek B.

    2015-06-01

    Recent technological advances in the isolation and transfer of different 2-dimensional (2D) materials have led to renewed interest in stacked Van der Waals (vdW) heterostructures. Interlayer interactions and lattice mismatch between two different monolayers cause elastic strains, which significantly affects their electronic properties. Using a multiscale computational method, we demonstrate that significant in-plane strains and the out-of-plane displacements are introduced in three different bilayer structures, namely graphene-hBN, MoS2-WS2 and MoSe2-WSe2, due to interlayer interactions which can cause bandgap change of up to ~300 meV. Furthermore, the magnitude of the elastic deformations can be controlled by changing the relative rotation angle between two layers. Magnitude of the out-of-plane displacements in graphene agrees well with those observed in experiments and can explain the experimentally observed bandgap opening in graphene. Upon increasing the relative rotation angle between the two lattices from 0° to 10°, the magnitude of the out-of-plane displacements decrease while in-plane strains peaks when the angle is ~6°. For large misorientation angles (>10°), the out-of-plane displacements become negligible. We further predict the deformation fields for MoS2-WS2 and MoSe2-WSe2 heterostructures that have been recently synthesized experimentally and estimate the effect of these deformation fields on near-gap states.

  18. Deformation mechanisms, architecture, and petrophysical properties of large normal faults in platform carbonates and their role in the release of carbon dioxide from earth's interior in central Italy

    Science.gov (United States)

    Agosta, Fabrizio

    2006-04-01

    A challenging theme of research in structural geology is the process of faulting in carbonate rocks: how do the resulting internal architecture and petrophysical properties of faults affect subsurface fluid flow. A better understanding of this process is important to evaluate the potential oil and gas recovery from carbonate reservoirs, and to plan CO 2 containment in the depleted reservoirs. Carbonate rocks may deform with different mechanisms depending primarily on their original sedimentary fabric, diagenetic history, fluid content, and tectonic environment. In this dissertation I investigate the deformation mechanisms, petrophysics, and internal fluid composition of large, seismic, basin-bounding normal faults in low porosity platform carbonates. Based on the nature, orientation, and abutting relationships of the structural elements preserved within the faults and in the surrounding carbonate host rocks, I was able to characterize the mechanisms of fault growth and the fault architecture. Incipient faulting occurred at shallow depths by sequential formation and shearing of pressure solution seams and joints/veins; with ongoing deformation and exhumation, the joint-based mechanism became predominant. The end result is a mature normal fault that juxtaposes basin sedimentary rocks of the hanging wall against deformed carbonates of the footwall. The deformed carbonates of the fault footwalls are composed of rocks with low porosity and permeability and major slip surfaces in the fault core, and fragmented carbonate matrices with high porosity and permeability, and small faults in the damage zone. The degree of fragmentation in the damage zone generally increases towards the fault hanging wall, forming structural domains characterized by different deformation intensity. The rocks of the fault core have sub-spherical pores, those of the damage zone have elongated, crack-like, pores. The permeability structure of the normal fault zones is therefore made up of a fault core that acts as a barrier to fluid flow, and fragmented carbonates that enhance fluid flow. Stable isotope geochemistry data shows two main sources of the fluids that precipitated minerals within the normal faults. The main fluid source is infiltrated meteoric water, the second is CO2-enriched groundwater. Both fluids compartmentalized primarily along the major slip surfaces of the fault cores.

  19. 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)

    Kruckenberg, S. C.; Tikoff, B.

    2012-12-01

    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).

  20. Influency of ordered phase precipitation on mechanical properties and deformation character of single crystals of ageing Ni-14.4 at. % Mo alloy

    International Nuclear Information System (INIS)

    Investigated were the particularities of the ageing Ni-14.4 at.% Mo alloy structure, formed in the course of an isothermal annealing at 700 deg C. The effect of the precipitation of the NiMo ordered phase upon the strength properties of alloy single-crystals has been studied. The character of the dislocation structure of variously treated alloys on various stages of deformation has been studied. The conditions of the transition of the preferable slipping from the primary system to the associated system have been deermined and a conclusion has been drawn that this transition is caused by the attainment of the ''limit'' level of strengthening in the primary system

  1. Deformation and properties of ribbons of amorphous FeCo80-xSi15Bx alloys

    International Nuclear Information System (INIS)

    Change in morphology of shear bands, propagation of micro- and macrocracks, structure as well as coercive force Hc of rolled strips of Fe5Co80-xSi15Bx amorphous alloys, is studied, where x has the following values: 8.2; 10; 11.8 at.%. The found essential (more than 200 times) increase of Hc after deformation is explained by appearance of internal stresses, microcracks and nuclei of crystal phase

  2. One-particle properties of deformed N $\\approx$ 28 odd-N nuclei with weakly-bound or resonant neutrons

    CERN Document Server

    Hamamoto, Ikuko

    2008-01-01

    Possible deformation of odd-N nuclei with N $\\approx$ 28 towards the neutron drip line is investigated using the Nilsson diagram based on deformed Woods-Saxon potentials. Both weakly-bound and resonant one-particle levels are properly obtained by directly solving the Schr\\"{o}dinger equation in mesh of space coordinate with the correct boundary condition. If we use the same diffuseness of the potential as that of $\\beta$-stable nuclei, the energy difference between the neutron 2p$_{3/2}$ and 1f$_{7/2}$ levels becomes very small or the N=28 energy gap almost disappears, as the binding energies of those levels approach zero. This suggests that the ground states of those neutron drip line nuclei are likely to be deformed. In particular, the spin-parity and the magnetic moment of the ground state of odd-N nuclei, $^{43}_{16}$S$_{27}$ and $^{45}_{16}$S$_{29}$, are examined. Moreover, it is suggested that in $^{39}_{12}$Mg$_{27}$ lying outside the drip line the lowest resonant state may have 5/2$^{-}$, if the N=28 ...

  3. q-Deformed Dynamics and Virial Theorem

    OpenAIRE

    Zhang, Jian-zu

    2002-01-01

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

  4. Proposal for the award of a contract for the supply of superconducting octupole corrector magnets for the LHC

    CERN Document Server

    2000-01-01

    This document concerns the award of a contract for the supply of 168 MO superconducting octupole corrector magnet assemblies for the LHC. Following a market survey (MS-2594/LHC/LHC) carried out among 39 firms in thirteen Member States, two firms in Japan and one firm in the USA, a call for tenders (IT-2595/LHC/LHC) was sent on 15 February 2000 to 11 firms in seven Member States. By the closing date, CERN had received seven tenders. The Finance Committee is invited to agree to the negotiation of a contract with the firm ANTEC (ES), the lowest bidder, for the supply of 168 MO superconducting octupole corrector magnet assemblies for the LHC for a total amount of 2 075 935 Swiss francs, subject to revision for contractual deliveries after 31 December 2001, with an option for the supply of up to 50 additional MO corrector magnet assemblies, for a total amount of 526 400 Swiss francs, subject to revision for contractual deliveries after 31 December 2001, bringing the total amount to a maximum of 2 602 335 Swiss fra...

  5. 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 $^{132}$Sn 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(E3) 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 protons and neutrons...

  6. Basic-deformed quantum mechanics

    OpenAIRE

    Lavagno, A

    2009-01-01

    Starting on the basis of $q$-symmetric oscillator algebra and on the associate $q$-calculus properties, we study a deformed quantum mechanics defined in the framework of the basic square-integrable wave functions space. In this context, we introduce a deformed Schroedinger equation, which satisfies the main quantum mechanics assumptions and admits, in the free case, plane wave functions that can be expressed in terms of the q-deformed exponential, originally introduced in the framework of the...

  7. Experimental Study of the Bending Properties and Deformation Analysis of Web-Reinforced Composite Sandwich Floor Slabs with Four Simply Supported Edges.

    Science.gov (United States)

    Qi, Yujun; Fang, Hai; Liu, Weiqing

    2016-01-01

    Web-reinforced composite sandwich panels exhibit good mechanical properties in one-way bending, but few studies have investigated their flexural behavior and deformation calculation methods under conditions of four simply supported edges. This paper studies the bending performance of and deformation calculation methods for two-way web-reinforced composite sandwich panels with different web spacing and heights. Polyurethane foam, two-way orthogonal glass-fiber woven cloth and unsaturated resin were used as raw materials in this study. Vacuum infusion molding was used to prepare an ordinary composite sandwich panel and 5 web-reinforced composite sandwich panels with different spacing and web heights. The panels were subjected to two-way panel bending tests with simple support for all four edges. The mechanical properties of these sandwich panels during the elastic stage were determined by applying uniformly distributed loads. The non-linear mechanical characteristics and failure modes were obtained under centrally concentrated loading. Finally, simulations of the sandwich panels, which used the mechanical model established herein, were used to deduce the formulae for the deflection deformation for this type of sandwich panel. The experimental results show that webs can significantly improve the limit bearing capacity and flexural rigidity of sandwich panels, with smaller web spacing producing a stronger effect. When the web spacing is 75 mm, the limit bearing capacity is 4.63 times that of an ordinary sandwich panel. The deduced deflection calculation formulae provide values that agree well with the measurements (maximum error <15%). The results that are obtained herein can provide a foundation for the structural design of this type of panel. PMID:26871435

  8. Effect of Deformation and Aging on Properties of Al-4.1%Cu-1.4%Mg Aluminum Alloy

    OpenAIRE

    Wang, Hao; Li, Changsheng; Li, Jing; Wei, Xinglong; Mei, Ruibin

    2013-01-01

    Deformation scheme and preheat treatment of Al-4.1%Cu-1.4%Mg aluminum alloy are chosen, homogenizing annealing at 430°C for 1.5?h, cooling to 250°C in furnace at a cooling rate of less than 30°C/h and then cooling to room temperature to make Al-4.1%Cu-1.4%Mg aluminum alloy annealed fully. Heat treatment tests of Al-4.1%Cu-1.4%Mg aluminum alloy mainly consisting of rolling and aging were conducted, and the optimum peak of aging mechanism is 190°C/12?h. Through comparison of microstructure and ...

  9. Backbending in deformed nuclei

    International Nuclear Information System (INIS)

    In the last few years, the deformed nuclei situated in the region of the rare earth elements have been investigated intensively. Thereby several new properties, for instance the backbending effect and the existence of decoupled bands, have been observed. These phenomena are described in this paper. (orig.)

  10. Quantifying the Mechanical Properties of Materials and the Process of Elastic-Plastic Deformation under External Stress on Material

    Directory of Open Access Journals (Sweden)

    Jan Valí?ek

    2015-11-01

    Full Text Available The paper solves the problem of the nonexistence of a new method for calculation of dynamics of stress-deformation states of deformation tool-material systems including the construction of stress-strain diagrams. The presented solution focuses on explaining the mechanical behavior of materials after cutting by abrasive waterjet technology (AWJ, especially from the point of view of generated surface topography. AWJ is a flexible tool accurately responding to the mechanical resistance of the material according to the accurately determined shape and roughness of machined surfaces. From the surface topography, it is possible to resolve the transition from ideally elastic to quasi-elastic and plastic stress-strain states. For detecting the surface structure, an optical profilometer was used. Based on the analysis of experimental measurements and the results of analytical studies, a mathematical-physical model was created and an exact method of acquiring the equivalents of mechanical parameters from the topography of surfaces generated by abrasive waterjet cutting and external stress in general was determined. The results of the new approach to the construction of stress-strain diagrams are presented. The calculated values agreed very well with those obtained by a certified laboratory VÚHŽ.

  11. 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)

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

    2013-12-15

    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.)

  12. Isoscalar octupole transition rates in 50Ti, 52Cr and 208Pb from model-independent analyses of 104 MeV ?-particle scattering

    International Nuclear Information System (INIS)

    Applying a recently proposed method for model-independent analyses experimental differential cross sections for 104 MeV ?-particle scattering have been analyzed. Reliable values of isoscalar (0+-3-1) octupole transition rates in 50Ti, 52Cr and 208 Pb are presented and compared with electromagnetic rates. (orig.)

  13. One-phonon octupole vibrational states in 136Xe, 137Cs, 138Ba, 140Ce and 142Nd with N = 82

    International Nuclear Information System (INIS)

    Excited high spin states in 136Xe, 137Cs, 138Ba, 140Ce and 142Nd with N = 82 are reorganized and interpreted in terms of the weak coupling mode of an octupole 3- phonon. Nearly identical sequences of levels with ?I = 3 and ?? = yes built on 17/2+ and 23/2- states are found, for the first time, up to 29/2+ and 35/2-, respectively, for 22 states of 137Cs. Also, nearly identical sequences of levels with ?I = 3 and ?? = yes built on the 6+ and 9- states are found, for the first time, up to 14+ and 17-, respectively, for 18 states of 136Xe, up to 14+ and 17-, respectively, for 24 states of 138Ba and up to 11+ and 14-, respectively, for 14 states of 140Ce. New spins and parities are assigned, tentatively, to the high spin states of these nuclei based on the weak coupling mode of an octupole 3- phonon. The weak coupling of an octupole 3- phonon needs to be considered when single particle configurations are assigned to high spin states. Neutron particle-hole states (?h11/2-1 f7/2+1) with weak coupling of an octupole 3- phonon are proposed, for the first time. The ?h11/2-1 f7/2+1 excitation energies (Eext(1p1h)) are nearly constant with increasing of Z. One-phonon excited states in 136Xe, 137Cs, 138Ba and 140Ce have the stretched weak coupling configurations of ?I = 3. But one-phonon excited states in 142Nd show the non-stretched weak coupling configurations of an octupole phonon with ?I = 3 and 2. (orig.)

  14. Multipole modes in deformed nuclei within the finite amplitude method

    Science.gov (United States)

    Kortelainen, M.; Hinohara, N.; Nazarewicz, W.

    2015-11-01

    Background: To access selected excited states of nuclei, within the framework of nuclear density functional theory, the quasiparticle random phase approximation (QRPA) is commonly used. Purpose: We present a computationally efficient, fully self-consistent framework to compute the QRPA transition strength function of an arbitrary multipole operator in axially deformed superfluid nuclei. Methods: The method is based on the finite amplitude method (FAM) QRPA, allowing fast iterative solution of QRPA equations. A numerical implementation of the FAM-QRPA solver module has been carried out for deformed nuclei. Results: The practical feasibility of the deformed FAM module has been demonstrated. In particular, we calculate the quadrupole and octupole strengths in a heavy deformed nucleus 240Pu, without any truncations in the quasiparticle space. To demonstrate the capability to calculate individual QRPA modes, we also compute low-lying negative-parity collective states in 154Sm. Conclusions: The new FAM implementation enables calculations of the QRPA strength function throughout the nuclear landscape. This will facilitate global surveys of multipole modes and ? decays and will open new avenues for constraining the nuclear energy density functional.

  15. New high-spin states of {sup 147}Nd and {sup 145}Ce: Octupole correlation in the N=87 isotones

    Energy Technology Data Exchange (ETDEWEB)

    Venkova, Ts.; Petkov, P. [Univ. Paris-Sud, Orsay (France). CNRS; Bulgarian Academy of Sciences, Sofia (Bulgaria). Inst. of Nuclear Research; Porquet, M.-G.; Astier, A.; Deloncle, I.; Prevost, A. [IN2P3-CNRS/Universite Paris-Sud, CSNSM, Orsay (France); Azaiez, F.; Buta, A.; Curien, D.; Dorvaux, O.; Duchene, G.; Gall, B.J.P.; Khalfallah, F.; Piqueras, I.; Rousseau, M. [IN2P3-CNRS/Universite Louis Pasteur, IReS, Strasbourg Cedex 2 (France); Bogachev, A. [JINR, Dubna, Moscow region (Russian Federation); Durell, J.; Roach, A. [University of Manchester, Department of Physics and Astronomy, Manchester (United Kingdom); Houry, M.; Lucas, R.; Theisen, Ch. [CEA/DSM/DAPNIA/SPhN, Commissariat a l' Energie Atomique, Gif-sur-Yvette Cedex (France); Meyer, M.; Redon, N.; Stezowski, O. [IN2P3-CNRS/Universite Claude Bernard, IPNL, Villeurbanne Cedex (France)

    2005-12-01

    High-spin states of the N=87 nuclei, {sup 147}Nd and {sup 145}Ce, have been populated in the {sup 12}C+{sup 238}U and {sup 18}O+{sup 208}Pb fusion-fission reactions at 90 MeV and 85 MeV bombarding energy, respectively. The emitted {gamma}-radiation was detected using the Euroball III and IV arrays. High-spin states of the {sup 147}Nd isotope have been identified for the first time. The high-spin yrast and near-to-yrast structures of the {sup 145}Ce nucleus have been considerably extended. The newly observed structures, discussed by analogy with the neighbouring isotones, show the coupling of an h{sub 9/2} neutron to the quadrupole and octupole excitations of the core. (orig.)

  16. New high-spin states of 147Nd and 145Ce: Octupole correlation in the N=87 isotones

    International Nuclear Information System (INIS)

    High-spin states of the N=87 nuclei, 147Nd and 145Ce, have been populated in the 12C+238U and 18O+208Pb fusion-fission reactions at 90 MeV and 85 MeV bombarding energy, respectively. The emitted ?-radiation was detected using the Euroball III and IV arrays. High-spin states of the 147Nd isotope have been identified for the first time. The high-spin yrast and near-to-yrast structures of the 145Ce nucleus have been considerably extended. The newly observed structures, discussed by analogy with the neighbouring isotones, show the coupling of an h9/2 neutron to the quadrupole and octupole excitations of the core. (orig.)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-04-01

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

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

    International Nuclear Information System (INIS)

    Excited states in 137Te, populated in spontaneous fission of 248Cm, were studied by means of prompt-γ spectroscopy, using the EUROGAM2 multidetector array. This is the first observation of excited states in 137Te. The yrast excitations of 137Te are due to the three valence neutrons, occupying the νf7/2 and νh9/2 orbitals, similarly as observed in its heavier N=85 isotones. Systematic comparison of excited levels in the N=85 isotones shows inconsistencies in spin and parity assignments in 139Xe and 141Ba nuclei. The new data for 137Te do not confirm earlier suggestions that octupole correlations increase in the N=85 isotones, close to the Z=50 closed shell. (c) 2000 The American Physical Society

  19. Influence of Partitioning Process on the Microstructure and Mechanical Properties of High Deformability Oil-Gas Pipeline

    OpenAIRE

    Ma, Jing; Zhang, Xiaoyong; Cheng, Shixia; Gao, Huilin

    2014-01-01

    Multiphase structure of bainite and M/A constituent can be obtained for X80 oil-gas pipeline through a novel heat online partitioning (HOP) technology. The effects of partitioning temperature on the microstructure and mechanical properties of the experimental steels were researched by means of mechanical properties test, microscopic analysis, and X-ray diffraction. The results show that with the increase of the partitioning temperature, the strength of the experimental steel decreases and the...

  20. An investigation to the effect of deformation-heat treatment cycle on the eutectic morphology and mechanical properties of a Thixocast A356 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Haghshenas, M., E-mail: mhaghshe@uwo.ca [School of Metallurgical and Materials Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Zarei-Hanzaki, A. [School of Metallurgical and Materials Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Jahazi, M. [Aerospace Manufacturing Technology Centre, Institute for Aerospace Research, National Research Council Canada, 5145 Decelles Avenue, Montreal, Quebec, H3T 2B2 (Canada)

    2009-08-15

    The influences of deformation, heat treatment temperature and holding time on morphology and size distribution of Si containing eutectic phases of Thixocast Al-7Si-0.4 Mg alloy were investigated. The novel thermo-mechanical treatment consisted of initial cold working practice followed by a solution heat treatment at 540 deg. C for durations ranging from 2 min to 120 min followed by water quenching. Optical and scanning electron microscopes were used to study the influence of process parameters on microstructure evolution. Also, final mechanical properties were investigated using hardness test. The results indicate that, under appropriate conditions it is possible to achieve an ultrafine grain microstructure with the eutectic Si fibers fragmented and spheroidized in the entire microstructure. It was also found that, an agglomeration of sphrodized particles occurs and is governed by Ostwald ripening mechanism.

  1. 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.

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    1987-01-01

    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.

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

    International Nuclear Information System (INIS)

    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)-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 1/4 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

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

    Directory of Open Access Journals (Sweden)

    Ju Shin-Pon

    2011-01-01

    Full Text Available Abstract The effect of uni-axial strain on the electronic properties of (8,0 zigzag and (5,5 armchair boron nitride nanotubes (BNNT is addressed by density functional theory calculation. The stress-strain profiles indicate that these two BNNTS of differing types display very similar mechanical properties, but there are variations in HOMO-LUMO gaps at different strains, indicating that the electronic properties of BNNTs not only depend on uni-axial strain, but on BNNT type. The variations in nanotube geometries, partial density of states of B and N atoms, B and N charges are also discussed for (8,0 and (5,5 BNNTs at different strains.

  6. Mineral preferred orientation and magnetic properties as indicators of varying strain conditions in naturally deformed iron ore.

    Czech Academy of Sciences Publication Activity Database

    Günther, A.; Brokmeier, H. G.; Petrovský, Eduard; Siemes, H.; Helming, K.; Quade, H.

    A74, Suppl. (2002), s. S1080-S1082. ISSN 0947-8396 Institutional research plan: CEZ:AV0Z3012916 Keywords : magnetic properties * iron ore * Brazil * magnetic susceptibility Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 2.231, year: 2002

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

    OpenAIRE

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

    2008-01-01

    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 boundaries is observed. Thi...

  8. Elastic Properties in Tension and Shear of High Strength Nonferrous Metals and Stainless Steel - Effect of Previous Deformation and Heat Treatment

    Science.gov (United States)

    Mebs, R W; Mcadam, D J

    1947-01-01

    A resume is given of an investigation of the influence of plastic deformation and of annealing temperature on the tensile and shear elastic properties of high strength nonferrous metals and stainless steels in the form of rods and tubes. The data were obtained from earlier technical reports and notes, and from unpublished work in this investigation. There are also included data obtained from published and unpublished work performed on an independent investigation. The rod materials, namely, nickel, monel, inconel, copper, 13:2 Cr-Ni steel, and 18:8 Cr-Ni steel, were tested in tension; 18:8 Cr-Ni steel tubes were tested in shear, and nickel, monel, aluminum-monel, and Inconel tubes were tested in both tension and shear. There are first described experiments on the relationship between hysteresis and creep, as obtained with repeated cyclic stressing of annealed stainless steel specimens over a constant load range. These tests, which preceded the measurements of elastic properties, assisted in devising the loading time schedule used in such measurements. From corrected stress-set curves are derived the five proof stresses used as indices of elastic or yield strength. From corrected stress-strain curves are derived the secant modulus and its variation with stress. The relationship between the forms of the stress-set and stress-strain curves and the values of the properties derived is discussed. Curves of variation of proof stress and modulus with prior extension, as obtained with single rod specimens, consist in wavelike basic curves with superposed oscillations due to differences of rest interval and extension spacing; the effects of these differences are studied. Oscillations of proof stress and modulus are generally opposite in manner. The use of a series of tubular specimens corresponding to different amounts of prior extension of cold reduction gave curves almost devoid of oscillation since the effects of variation of rest interval and extension spacing were removed. Comparison is also obtained between the variation of the several properties, as measured in tension and in shear. The rise of proof stress with extension is studied, and the work-hardening rates of the various metals evaluated. The ratio between the tensile and shear proof stresses for the various annealed and cold-worked tubular metals is likewise calculated. The influence of annealing or tempering temperature on the proof stresses and moduli for the cold-worked metals and for air-hardened 13:2 Cr-Ni steel is investigated. An improvement of elastic strength generally is obtained, without important loss of yield strength, by annealing at suitable temperature. The variation of the proof stress and modulus of elasticity with plastic deformation or annealing temperature is explained in terms of the relative dominance of three important factors: namely, (a) internal stress, (b) lattice-expansion or work-hardening, and (c) crystal reorientation. Effective values of Poisson's ratio were computed from tensile and shear moduli obtained on tubular specimens. The variation of Poisson's ratio with plastic deformation and annealing temperature is explained in terms of the degree of anisotropy produced by changes of (a) internal stress and (b) crystal orientation.

  9. Improving the mechanical properties of Zr-based bulk metallic glass by controlling the activation energy for ?-relaxation through plastic deformation

    Energy Technology Data Exchange (ETDEWEB)

    Adachi, Nozomu; Todaka, Yoshikazu, E-mail: todaka@me.tut.ac.jp; Umemoto, Minoru [Department of Mechanical Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku, Toyohashi, Aichi 441-8580 (Japan); Yokoyama, Yoshihiko [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan)

    2014-09-29

    The mechanism of plastic deformation in bulk metallic glasses (BMGs) is widely believed to be based on a shear transformation zone (STZ). This model assumes that a shear-induced atomic rearrangement occurs at local clusters that are a few to hundreds of atoms in size. It was recently postulated that the potential energy barrier for STZ activation, W{sub STZ}, calculated using the cooperative shear model, is equivalent to the activation energy for ?-relaxation, E{sub ?}. This result suggested that the fundamental process for STZ activation is the mechanically activated ?-relaxation. Since the E{sub ?} value and the glass transition temperature T{sub g} of BMGs have a linear relation, that is, because E{sub ?}???26RT{sub g}, the composition of the BMG determines the ease with which the STZ can be activated. Enthalpy relaxation experiments revealed that the BMG Zr{sub 50}Cu{sub 40}Al{sub 10} when deformed by high-pressure torsion (HPT) has a lower E{sub ?} of 101?kJ/mol. The HPT-processed samples accordingly exhibited tensile plastic elongation (0.34%) and marked decreases in their yield strength (330?MPa). These results suggest that mechanically induced structural defects (i.e., the free volume and the anti-free volume) effectively act to reduce W{sub STZ} and increase the number of STZs activated during tensile testing to accommodate the plastic strain without requiring a change in the composition of the BMG. Thus, this study shows quantitatively that mechanically induced structural defects can overcome the compositional limitations of E{sub ?} (or W{sub STZ}) and result in improvements in the mechanical properties of the BMG.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.)

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

    Energy Technology Data Exchange (ETDEWEB)

    Smirnova, N.A.; Van Isacker, P. [Grand Accelerateur National d' Ions Lourds (GANIL), 14 - Caen (France); Smirnova, N.A [Paris-11 Univ., 91 - Orsay (France). Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse]|[Institute for Nuclear Physics, Moscow State University (Russian Federation); Pietralla, N. [Institut fur Kernphysik, Universitat zu Koln (Germany)]|[Yale Univ., New Haven, CT (United States). Wright Nuclear Structure Lab; Mizusaki, T. [Tokyo Univ. (Japan). Dept. of Physics

    2000-07-01

    The interrelation between the octupole phonon and the low-lying proton-neutron mixed-symmetry quadrupole in near-spherical nuclei is investigated. The one-phonon states decay by collective E3 and E2 transitions to the ground state and by relatively strong E1 and M1 transitions to the isoscalar 2{sup +}{sub 1} state. We apply the proton-neutron version of the Interacting Boson Model including quadrupole and octupole bosons (sdf-IBM-2). Two F-spin symmetric dynamical symmetry limits of the model, namely the vibrational and the {gamma}-unstable ones, are considered. We derived analytical formulae for excitation energies as well as B(E1), B(M1), B(E2), and B(E3) values for a number of transitions between low-lying states. The model well reproduces many known transition strengths in the near spherical nuclei {sup 142}Ce and {sup 94}Mo. (authors)

  12. Observation of the nuclear magnetic octupole moment of $^{173}$Yb from precise measurements of hyperfine structure in the ${^3P}_2$ state

    CERN Document Server

    Singh, Alok K; Natarajan, Vasant

    2015-01-01

    We measure hyperfine structure in the metastable ${^3P}_2$ state of $^{173}$Yb and extract the nuclear magnetic octupole moment. We populate the state using dipole-allowed transitions through the ${^3P}_1$ and ${^3S}_1$ states. We measure frequencies of hyperfine transitions of the ${^3P}_2 \\rightarrow {^3S}_1$ line at 770 nm using a Rb-stabilized ring cavity resonator with a precision of 200 kHz. Second-order corrections due to perturbations from the nearby ${^3P}_1$ and ${^1P}_1$ states are below 30 kHz. We obtain the hyperfine coefficients as: $A=-742.11(2)$ MHz, $B=1339.2(2)$ MHz, which represent two orders-of-magnitude improvement in precision, and $C=0.54(2)$ MHz. From atomic structure calculations, we obtain the nuclear moments: quadrupole $Q=2.46(12)$ b and octupole $\\Omega=-34.4(21)$ b\\,$\\times \\mu_N$.

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

    International Nuclear Information System (INIS)

    The interrelation between the octupole phonon and the low-lying proton-neutron mixed-symmetry quadrupole in near-spherical nuclei is investigated. The one-phonon states decay by collective E3 and E2 transitions to the ground state and by relatively strong E1 and M1 transitions to the isoscalar 2+1 state. We apply the proton-neutron version of the Interacting Boson Model including quadrupole and octupole bosons (sdf-IBM-2). Two F-spin symmetric dynamical symmetry limits of the model, namely the vibrational and the γ-unstable ones, are considered. We derived analytical formulae for excitation energies as well as B(E1), B(M1), B(E2), and B(E3) values for a number of transitions between low-lying states. The model well reproduces many known transition strengths in the near spherical nuclei 142Ce and 94Mo. (authors)

  14. Effect of warm deformation on microstructure and mechanical properties of a layered and nanostructured 304 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Chen, A.Y.; Shi, S.S.; Tian, H.L. [School of Material Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093 (China); Ruan, H.H. [Department of Mechanical Engineering, Hong Kong University of Science and Technology, Hong Kong (China); Li, X. [School of Material Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093 (China); Pan, D., E-mail: feiyu.dpan@gmail.com [School of Material Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093 (China); Lu, J. [College of Science and Engineering, City University of Hong Kong, Hong Kong (China)

    2014-02-10

    A layered and nanostructured (LN) stainless steel was fabricated by surface mechanical attrition treatment (SMAT) combined with warm co-rolling (WCR) in order to improve the low ductility of nanostructured metallic materials. The influences of rolling temperature and strain on the microstructure are investigated. The microstructure of LN steel is characterized by methods of transmission electron microscopy (TEM), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The experimental results reveal that the microstructure of LN steels presents a periodic distribution of nanocrystalline layer, ultra-fine grained layer and coarse grained layer with graded transition of grain size. The integrated effects of SMAT and WCR on the refinement of grain size, involving in dislocation subdivision, twinning and dynamic recrystallization, are discussed. The tensile properties of LN steels exhibit both high strength and good ductility resulting from good work hardening behavior. The strengthening mechanisms by grain size refinement, ??-martensite transformation and twinning are explored.

  15. Comparison between the sandy and the shaly facies of the Opalinus Clay (Mont Terri, Switzerland): mechanical properties obtained from triaxial deformation, mineralogical composition and micro fabric

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. In Switzerland, the international research project Mont Terri investigates the Opalinus Clay (Jurassic formation) in the underground rock laboratory (URL) Mont Terri. The Opalinus Clay is subdivided into different facies (sandy, shaly, and carbonate rich facies). In the Mont Terri URL the sandy facies is less abundant and only a relatively thin layer of the carbonate rich facies is present. The currently favored HLRW repository site in Switzerland, however, is supposed to be in the sandy facies of the Opalinus Clay. Yet, most of the investigations focused on the shaly facies. Generally the understanding of the relation of properties and performances of clays and clay-stones is poor which is relevant for mineralogical micro fabric but also mechanical processes. For the safety assessment of the repository models describing both chemical and mechanical processes are required. Such models have to be based on a solid understanding of the mechanisms behind the processes considered. With respect to the understanding of the deformation behavior of different Opalinus Clay samples, Klinkenberg et al. (2009) found the carbonates to play a major role. For different samples of the shaly facies they found carbonate to represent a kind of predetermined breaking planes. Therefore, carbonate rich materials showed lower mechanical strengths. Interestingly, they also observed the opposite when considering samples of the Callovo-Oxfordian clay, which is investigated in France. Considering the micro fabric of all samples suggests that the carbonate - mechanical strength relation depends on the type and amount of carbonates. Therefore, Kaufhold et al. investigated the micro fabric - mechanical strength relation of the sandy facies. They concluded that the sandy facies is comparable with the investigated samples of the Callovo-Oxfordian clay. The mechanical behavior of the shaly facies was already investigated. A detailed comparison of samples from both main facies of the Opalinus clay, however, is missing. In this study, therefore, the investigation of the sandy facies and shaly facies with focus on the relation between micro fabric, mineralogical composition, and mechanical deformation behavior is presented. The sandy and the shaly facies both show the same mineral inventory but different contents. The shaly facies has a clay mineral content between 60 to 70 wt% (within 10-15 wt% swellable phases), whereas the sandy facies only has a clay mineral content of 15-25% (within dev.peak approximately twice as high as it was found for the shaly facies. The results are supposed to improve the understanding of the mechanical properties of clays, particularly with respect to the variability of mineral composition, micro fabric, and mechanical behavior. (authors)

  16. Effect of heat treatment on deformation and mechanical properties of 8 mol% yttria-stabilized zirconia by Berkovich nanoindentation

    Science.gov (United States)

    Mao, W. G.; Luo, J. M.; Dai, C. Y.; Shen, Y. G.

    2015-05-01

    The effect of thermal treatment on the elasto-plastic transition and mechanical properties of air plasma-sprayed 8 mol% Y2O3-stabilized ZrO2 (8YSZ) thermal barrier coatings was studied by nanoindentation test at ultra-low loads with a Berkovich indenter. The area contact function of the indenter was calibrated repeatedly under nano-scales, and the indenter tip radius was estimated under different indentation depths, respectively. Owing to the heterogeneous and porous microstructure, the scatter of all collected experimental data was analyzed by Weibull statistic method. It is interesting to observe that the hardness exhibits an apparent reverse indentation size effect under very small depths. The Young's modulus of 8YSZ varies with ranging from 213 to 246 GPa due to the sintering effect. True hardness of 8YSZ increases from as-received 72.9 GPa to a top value 79.7 GPa under 100 thermal cycles, and then slightly decreases from this value to 75.5 GPa under 175 thermal cycles. The pure elastic and elasto-plastic indentation curves were obtained by adjusting the indentation load magnitude. The elasto-plastic transition and resolved shear stress fields were discussed carefully from the use of energetic models and Hertzian contact theory.

  17. Microstructure and mechanical properties of nanocrystalline titanium and Ti-Ta-Nb alloy manufactured using various deformation methods

    International Nuclear Information System (INIS)

    Mechanical properties and TEM microstructure studies have been carried out of nanocrystalline titanium, Ti10Nb10Ta and Ti10Nb obtained by various technological routes, including: powder metallurgy (ball milling and hot pressing), Equal Channel Angular Pressing (ECAP), hydroextrusion (HE) and high pressure torsion (HPT). The HE processed material in the form of 20 mm rods was extruded at a strain rate of 2.5 x 102 s-1 to a diameter of 3 mm, which corresponds to the true strain of 3.8. Resulting Yield Strength (YS) at the crystal size below 80 nm exceeded 1000 MPa, i.e. attained a value of 3 times more than the initial material. Equal-Channel Angular Pressing (ECAP) at 723 K was applied to produce nanostructured titanium. Grain refinement was observed already after one pass (considerable number of grains with d 20=1000. The additions of Nb and Ta resulted in a similar grain refinement but lower hardness. Uniaxial hot pressing at 650 C, followed by vacuum annealing resulted in similar microhardness as for powders. TEM studies performed using quantitative metallography allowed to estimate mean grain size at 150 nm. HPT technique at the pressure of 5 GPa resulted in finest grain size as compared to other preparation techniques leading to nanoscale grain refinement in Ti samples. The mean crystal size was estimated at about 30 nm. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-05-11

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

  19. One-phonon octupole vibrational states in {sup 136}Xe, {sup 137}Cs, {sup 138}Ba, {sup 140}Ce and {sup 142}Nd with N = 82

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-10-15

    Excited high spin states in {sup 136}Xe, {sup 137}Cs, {sup 138}Ba, {sup 140}Ce and {sup 142}Nd with N = 82 are reorganized and interpreted in terms of the weak coupling mode of an octupole 3{sup -} phonon. Nearly identical sequences of levels with {Delta}I = 3 and {Delta}{pi} = yes built on 17/2{sup +} and 23/2{sup -} states are found, for the first time, up to 29/2{sup +} and 35/2{sup -}, respectively, for 22 states of {sup 137}Cs. Also, nearly identical sequences of levels with {Delta}I = 3 and {Delta}{pi} = yes built on the 6{sup +} and 9{sup -} states are found, for the first time, up to 14{sup +} and 17{sup -}, respectively, for 18 states of {sup 136}Xe, up to 14{sup +} and 17{sup -}, respectively, for 24 states of {sup 138}Ba and up to 11{sup +} and 14{sup -}, respectively, for 14 states of {sup 140}Ce. New spins and parities are assigned, tentatively, to the high spin states of these nuclei based on the weak coupling mode of an octupole 3{sup -} phonon. The weak coupling of an octupole 3{sup -} phonon needs to be considered when single particle configurations are assigned to high spin states. Neutron particle-hole states ({nu}h{sub 11/2} {sup -1} f{sub 7/2} {sup +1}) with weak coupling of an octupole 3{sup -} phonon are proposed, for the first time. The {nu}h{sub 11/2} {sup -1} f{sub 7/2} {sup +1} excitation energies (E{sub ext}(1p1h)) are nearly constant with increasing of Z. One-phonon excited states in {sup 136}Xe, {sup 137}Cs, {sup 138}Ba and {sup 140}Ce have the stretched weak coupling configurations of {Delta}I = 3. But one-phonon excited states in {sup 142}Nd show the non-stretched weak coupling configurations of an octupole phonon with {Delta}I = 3 and 2. (orig.)

  20. Effect of heat treatment and plastic deformation on the structure and the mechanical properties of nitrogen-bearing 04N9Kh2A steel

    Science.gov (United States)

    Blinov, V. M.; Bannykh, O. A.; Lukin, E. I.; Kostina, M. V.; Blinov, E. V.

    2014-11-01

    The effect of the conditions of heat treatment and plastic deformation on the structure and the mechanical properties of low-carbon martensitic nickel steel (9 wt % Ni) with an overequilibrium nitrogen content is studied. The limiting strain to failure of 04N9Kh2A steel is found to be 40% at a rolling temperature of 20°C and 80% at a rolling temperature of 900°C. Significant strengthening of the steel (?0.2 = 1089 MPa) is obtained after rolling at a reduction of 40% at 20°C. The start and final temperatures of the ? ? ? transformation on heating and those of the ? ? ? transformation on cooling are determined by dilatometry. The specific features of the formation of the steel structure have been revealed as functions of the annealing and tempering temperatures. Electron-microscopic studies show that, after quenching from 850°C and tempering at 600°C for 1 h, the structure contains packet martensite with thin interlayers of retained austenite between martensite crystals. The strength of the nitrogen-bearing 04N9Kh2A steel after quenching from 850 and 900°C, cooling in water, and subsequent tempering at 500°C for 1 h is significantly higher than that of carboncontaining 0H9 steel used in cryogenic engineering.

  1. Cyclic Plastic Deformation and Welding Simulation:

    OpenAIRE

    Ten Horn, C.H.L.J.

    2003-01-01

    One of the concerns of a fitness for purpose analysis is the quantification of the relevant material properties. It is known from experiments that the mechanical properties of a material can change due to a monotonic plastic deformation or a cyclic plastic deformation. For a fitness for purpose analysis to be accurate in these cases, it has to take into account the current mechanical properties of the material. The problem is that the current properties may not always be known and retrieving ...

  2. Improving thermoelectric properties of n-type bismuth–telluride-based alloys by deformation-induced lattice defects and texture enhancement

    International Nuclear Information System (INIS)

    Repetitive hot deformation has been demonstrated as a new approach to obtain high-performance n-type bismuth–telluride-based alloys, benefiting from the deformation-induced lattice defects and texture enhancement. X-ray diffraction measurement showed that the oriented textures were greatly enhanced after repetitive hot deformation of the alloys with a quasi-layered crystal structure. The electrical conductivity was remarkably improved by the deformation-induced donor-like defect and texture enhancement, while the Seebeck coefficient remained almost unchanged, and consequently the room temperature power factor was significantly increased from 1.3 W m?1 K2, before hot deformation, to 2.9 W m?1 K2 after four hot deformations. The in-plane lattice thermal conductivity was also largely reduced by the generated high-density lattice defects during the hot-deformation process. The maximum ZT value for the repetitively hot-deformed samples reached 1.0 at 513 K, suggesting that the simple new top-down method is very promising for large-scale production of high-performance bismuth–telluride-based polycrystalline bulk materials.

  3. Cosmic Flows on 100 Mpc/h Scales: Standardized Minimum Variance Bulk Flow, Shear and Octupole Moments

    CERN Document Server

    Feldman, Hume A; Hudson, Michael J

    2009-01-01

    The low order moments of the large scale peculiar velocity field are sensitive probes of the matter density fluctuations on very large scales. However, peculiar velocity surveys have varying spatial distributions of tracers, and so the moments estimated are hard to model and thus are not directly comparable between surveys. In addition, the sparseness of typical proper distance surveys can lead to aliasing of small scale power into what is meant to be a probe of the largest scales. Here we extend our previous optimization analysis of the bulk flow to include the shear and octupole moments where velocities are weighted to give an optimal estimate of the moments of an idealized survey, with the variance of the difference between the estimate and the actual flow being minimized. These "minimum variance" (MV) estimates can be designed to calculate the moments on a particular scale with minimal sensitivity to small scale power, and thus different surveys can be directly compared. The MV moments were also designed ...

  4. Properties of seven-filament in situ MgB{sub 2}/Fe composite deformed by hydrostatic extrusion, drawing and rolling

    Energy Technology Data Exchange (ETDEWEB)

    Kovac, P [Institute of Electrical Engineering, Centre of Excellence CENG, Slovak Academy of Sciences, Dubravska cesta 9, 841 04 Bratislava (Slovakia); Husek, I [Institute of Electrical Engineering, Centre of Excellence CENG, Slovak Academy of Sciences, Dubravska cesta 9, 841 04 Bratislava (Slovakia); Pachla, W [Institute of High Pressure Physics, Polish Academy of Sciences, Sokolowska 29/37, 01-142 Warsaw (Poland); Kulczyk, M [Institute of High Pressure Physics, Polish Academy of Sciences, Sokolowska 29/37, 01-142 Warsaw (Poland)

    2007-07-15

    Seven-filament MgB{sub 2}/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 {mu}m down to 19 {mu}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 {mu}m. Thinner filaments show lower J{sub c} 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.

  5. A study of collective octupole states in barium in the interacting boson model

    International Nuclear Information System (INIS)

    We analyze low-lying collective negative parity states in 140-148Ba in terms of the interacting spdf boson model. We point out the crucial role played by p boson in describing E1 transitions. We discuss the rather unusual properties of the nucleus 146Ba. (orig.)

  6. Deformed General Relativity

    OpenAIRE

    Bojowald, Martin; Paily, George M.

    2012-01-01

    Deformed special relativity is embedded in deformed general relativity using the methods of canonical relativity and loop quantum gravity. Phase-space dependent deformations of symmetry algebras then appear, which in some regimes can be rewritten as non-linear Poincare algebras with momentum-dependent deformations of commutators between boosts and time translations. In contrast to deformed special relativity, the deformations are derived for generators with an unambiguous ph...

  7. Oxide dispersion strengthened ferritic alloys. 14/20% chromium: effects of processing on deformation texture, recrystallization and tensile properties; Alliages ferritiques 14/20% de chrome renforces par dispersion d`oxydes. Effets des procedes de mise en forme sur les textures de deformation, la recristallisation et les proprietes de traction

    Energy Technology Data Exchange (ETDEWEB)

    Regle, H.

    1994-12-31

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

  8. Effect of petrophysical properties and deformation on vertical zoning of metasomatic rocks in U-bearing volcanic structures: A case of the Strel'tsovka caldera, Transbaikal region

    Science.gov (United States)

    Petrov, V. A.; Andreeva, O. V.; Poluektov, V. V.

    2014-03-01

    The development of vertical zoning of wall-rock metasomatic alteration is considered with the Mesozoic Strel'tsovka caldera as an example. This caldera hosts Russia's largest uranium ore field. Metasomatic rocks with the participation of various phyllosilicates, carbonates, albite, and zeolites are widespread in the ore field. In the eastern block of the caldera, where the main uranium reserves are accommodated, hydromica metasomatic alteration gives way to beresitization with depth. Argillic alteration, which is typical of the western block, is replaced with hydromica and beresite alteration only at a significant depth. Postore argillic alteration is superposed on beresitized rocks in the lower part of the section. Two styles of vertical metasomatic zoning are caused by different modes of deformation in the western and eastern parts of the caldera. Variations of the most important petrophysical properties of host rocks—density, apparent porosity, velocities of P- and S-waves, dynamic Young's modulus, and Poisson coefficient—have been determined by sonic testing of samples taken from different depths. It is suggested that downward migration of the brittle-ductile transition zone could have been a factor controlling facies diversity of metasomatic rocks. Such a migration was caused by a new phase of tectonothermal impact accompanied by an increase in the strain rate or by emplacement of a new portion of heated fluid. Transient subsidence of the brittle-ductile boundary increases the depth of the hydrodynamically open zone related to the Earth's surface and accelerates percolation of cold meteoric water to a greater depth. As a result, the temperature of the hydrothermal solution falls down, increasing the vertical extent of argillic alteration. High-grade uranium mineralization is also localized more deeply than elsewhere.

  9. Third harmonic generation in organic octupole molecules with small absorption at 3ω

    International Nuclear Information System (INIS)

    The nonlinear optical properties of 1,3,5-tricyano-2,4,6-tri (p-diethylaminostyryl) benzene (TTB) thin films have been measured by using third-harmonic generation (THG) at the fundamental wavelength of 1064 nm. By comparing the THG intensity with that of fused silica, we estimated the third-order electrical susceptibility of the organic film to be 1.2 X10-11 esu, which is about 400 times larger than that of fused silica glass. Due to the unique properties of the TTB films, such as anomalous dispersion and small re-absorption of the third harmonic wave, a thick film is expected to give a more efficient THG, which can be applied to ultrafast optical correlators.

  10. Impact of chamber pressure and material properties on the deformation response of corneal models measured by dynamic ultra-high-speed Scheimpflug imaging

    Directory of Open Access Journals (Sweden)

    Fernando Faria Correia

    2013-10-01

    Full Text Available PURPOSE: To study the deformation response of three distinct contact lenses with known structures, which served as corneal models, under different chamber pressures using ultra-high-speed (UHS Scheimpflug imaging. METHODS: Three hydrophilic contact lenses were mounted on a sealed water chamber with precisely adjustable pressure: TAN-G5X (41% hydroxyethylmethacrylate/glycolmethacrylate, 550 µm thick, TAN-40 (62% hydroxyethylmethacrylate, 525 µm thick and TAN-58 (42% methylmethacrylate, 258 µm thick. Each model was tested five times under different pressures (5, 15, 25, 35 and 45 mmHg, using ultra-high-speed Scheimpflug imaging during non-contact tonometry. 140 Scheimpflug images were taken with the UHS camera in each measurement. The deformation amplitude during non-contact tonometry was determined as the highest displacement of the apex at the highest concavity (HC moment. RESULTS: At each pressure level, the deformation amplitude was statistically different for each lens tested (p<0.001, ANOVA. Each lens had different deformation amplitudes under different pressure levels (p<0.001; Bonferroni post-hoc test. The thicker lens with less polymer (TAN-G5X had a higher deformation (less stiff behavior than the one that was thinner but with more polymer (TAN-40, when measured at the same internal pressure. The thinnest lens with less polymers (TAN-58 had a lower deformation amplitude (stiffer behavior at higher pressures than the thicker ones with more polymer (TAN-40 and TAN-G5X at lower pressures. CONCLUSIONS: UHS Scheimpflug imaging allowed for biomechanical assessment through deformation characterization of corneal models. Biomechanical behavior was more influenced by material composition than by thickness. Chamber pressure had a significant impact on deformation response of each lens.

  11. Lie algebras Classification, Deformations and Rigidity

    CERN Document Server

    Goze, M

    2006-01-01

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

  12. Deformed aerogels in the superfluid 3He

    OpenAIRE

    Fomin, I. A.; Surovtsev, E. V.

    2015-01-01

    Deformed aerogels induce a global anisotropy in the superfluid 3He and orient the orbital part of its order parameter. Here a phenomenological theory of the orientational effect of elastic deformations of aerogels on the superfluid phases of 3He in the spirit of conventional theory of elasticity is formulated. Phenomenological coefficients, entering basic relations, depend on properties of given aerogel in the non-deformed state. Examples of originally isotropic silica aerog...

  13. The influence of ? phase stability on deformation mode and compressive mechanical properties of Ti–10V–3Fe–3Al alloy

    International Nuclear Information System (INIS)

    A metastable ?-Ti alloy, Ti–10V–3Fe–3Al (wt.%), was subjected to thermomechanical processing (TMP), where the temperature of isothermal holding in the ? + ? phase field was varied in order to change the volume fraction of the ? phase and, correspondingly, the ? phase stability. Following TMP, compression tests were performed at room temperature to evaluate the deformation mode. Microstructural features induced by compression were identified using transmission electron microscopy. It was found that {3 3 2}?1 1 3?? deformation twinning along with stress-induced products (?? martensite and ? lamellae) and slip were operational in the least stable ?. The co-existence of {3 3 2}?1 1 3?? and {1 1 2}?1 1 1?? twinning was found at intermediate ? stability along with other deformation products. With further increasing of ? phase stability, no {3 3 2}?1 1 3?? twinning was detected whereas other deformation modes remained unchanged. In stable ? phase, dislocation glide was the only deformation mode to be found. It was revealed that triggering stress required inducing the deformation products increases with the ? phase stability. Based on the findings, a modification of the lower portion of the Bo?–Md? phase stability diagram is proposed

  14. A novel deformation mechanism for superplastic deformation

    Energy Technology Data Exchange (ETDEWEB)

    Muto, H.; Sakai, M. (Toyohashi Univ. of Technology (Japan). Dept. of Materials Science)

    1999-01-01

    Uniaxial compressive creep tests with strain value up to -0.1 for a [beta]-spodumene glass ceramic are conducted at 1060 C. From the observation of microstructural changes between before and after the creep deformations, it is shown that the grain-boundary sliding takes place via cooperative movement of groups of grains rather than individual grains under the large-scale-deformation. The deformation process and the surface technique used in this work are not only applicable to explain the deformation and flow of two-phase ceramics but also the superplastic deformation. (orig.) 12 refs.

  15. Mechanical properties, microstructure and thermal stability of a nanocrystalline CoCrFeMnNi high-entropy alloy after severe plastic deformation

    International Nuclear Information System (INIS)

    An equiatomic CoCrFeMnNi high-entropy alloy (HEA), produced by arc melting and drop casting, was subjected to severe plastic deformation (SPD) using high-pressure torsion. This process induced substantial grain refinement in the coarse-grained casting leading to a grain size of approximately 50 nm. As a result, strength increased significantly to 1950 MPa, and hardness to ∼520 HV. Analyses using transmission electron microscopy (TEM) and 3-dimensional atom probe tomography (3D-APT) showed that, after SPD, the alloy remained a true single-phase solid solution down to the atomic scale. Subsequent investigations characterized the evolution of mechanical properties and microstructure of this nanocrystalline HEA upon annealing. Isochronal (for 1 h) and isothermal heat treatments were performed followed by microhardness and tensile tests. The isochronal anneals led to a marked hardness increase with a maximum hardness of ∼630 HV at about 450 °C before softening set in at higher temperatures. The isothermal anneals, performed at this peak hardness temperature, revealed an additional hardness rise to a maximum of about 910 HV after 100 h. To clarify this unexpected annealing response, comprehensive microstructural analyses were performed using TEM and 3D-APT. New nano-scale phases were observed to form in the originally single-phase HEA. After times as short as 5 min at 450 °C, a NiMn phase and Cr-rich phase formed. With increasing annealing time, their volume fractions increased and a third phase, FeCo, also formed. It appears that the surfeit of grain boundaries in the nanocrystalline HEA offer many fast diffusion pathways and nucleation sites to facilitate this phase decomposition. The hardness increase, especially for the longer annealing times, can be attributed to these nano-scaled phases embedded in the HEA matrix. The present results give new valuable insights into the phase stability of single-phase high-entropy alloys as well as the mechanisms controlling the mechanical properties of nanostructured multiphase composites

  16. Observation of hyperfine mixing in measurements of a magnetic octupole decay in isotopically pure nickel-like 129Xe and 132Xe ions

    Energy Technology Data Exchange (ETDEWEB)

    Trabert, E; Beiersdorfer, P; Brown, G V

    2006-12-21

    We present measurements of high statistical significance of the rate of the magnetic octupole (M3) decay in nickel-like ions of isotopically pure {sup 129}Xe and {sup 132}Xe. On {sup 132}Xe, an isotope with zero nuclear spin and therefore without hyperfine structure, the lifetime of the metastable level was established as (15.06 {+-} 0.24) ms. On {sup 129}Xe, an additional fast (2.7 {+-} 0.1 ms) decay component was established that represents hyperfine mixing with a level that decays by electric quadrupole (E2) radiation.

  17. Determination of the B(E3,0$^{+}$ $\\rightarrow$ 3$^{-}$) strength in the octupole correlated nuclei $^{142,144}$Ba using Coulomb excitation

    CERN Multimedia

    We propose to exploit the unique capability of ISOLDE to provide intense post-accelerated $^{142}$Ba and $^{144}$Ba ion beams from the HIE-ISOLDE facility to enable the Coulomb excitation of the first 3$^-$ state in these nuclei. By measuring the $\\gamma$-ray yields of the E1 decays from the 3$^-$ state using the MINIBALL array, we can obtain the interesting transition matrix element. The results will give quantitative information about octupole correlations in these nuclei. We require 33 shifts to fulfil the aims of the experiment.

  18. Determination of the B(E3;0$^+\\!\\rightarrow$ 3$^{-}$) strength in the octupole correlated nucleus $^{144}$Ba using Coulomb excitation

    CERN Multimedia

    We propose to exploit the unique capability of ISOLDE to provide intense post-accelerated $^{144}$Ba ion beams from the REX facility to enable the Coulomb excitation of the first 3 $^{-}$ state in this nucleus. By measuring the $\\gamma$-ray yields of the E1 decay connecting the 3$^{-}$ and 2$^{+}$ states using the MINIBALL array, we can obtain the interesting transition matrix element. The result will give quantitative information about octupole correlations in this nucleus. We require 27 shifts to fulfill the aims of the experiment.

  19. The ?h11/2-1?i13/2-2 three-hole isomeric state and octupole core excitation in the 205Tl nucleus

    International Nuclear Information System (INIS)

    New high-spin states were identified in the 205Tl isotope produced in deep-inelastic heavy-ion reactions. The expected 29/2+ yrast state and 35/2- isomeric state with 235 ns half-life were located above the 2.6 ?s isomer known from previous studies. Above this isomer a 7092 keV level was interpreted as a 41/2+ state arising from the coupling of the octupole vibration of the 208Pb core with the three-hole structure of the 35/2- isomer. (orig.)

  20. Plastic deformation mechanism in Mg--2%Be

    Energy Technology Data Exchange (ETDEWEB)

    Haslingerova, I.; Saxl, I.; Cech, B.

    1973-09-01

    Results of tensile tests in the range 20 to 500 deg C on magnesium composite rods are described. After mechanical treatment and recrystallization, a pronounced texture was discovered. Deformation mechanism and its relation to the preferred orientation were investigated. Mechanical properties were found to be affected by working and recrystallization textures. Nonbasal slip is proposed as the major operating deformation mechanism. (auth)

  1. Developing a Virtual Rock Deformation Laboratory

    Science.gov (United States)

    Zhu, W.; Ougier-simonin, A.; Lisabeth, H. P.; Banker, J. S.

    2012-12-01

    Experimental rock physics plays an important role in advancing earthquake research. Despite its importance in geophysics, reservoir engineering, waste deposits and energy resources, most geology departments in U.S. universities don't have rock deformation facilities. A virtual deformation laboratory can serve as an efficient tool to help geology students naturally and internationally learn about rock deformation. Working with computer science engineers, we built a virtual deformation laboratory that aims at fostering user interaction to facilitate classroom and outreach teaching and learning. The virtual lab is built to center around a triaxial deformation apparatus in which laboratory measurements of mechanical and transport properties such as stress, axial and radial strains, acoustic emission activities, wave velocities, and permeability are demonstrated. A student user can create her avatar to enter the virtual lab. In the virtual lab, the avatar can browse and choose among various rock samples, determine the testing conditions (pressure, temperature, strain rate, loading paths), then operate the virtual deformation machine to observe how deformation changes physical properties of rocks. Actual experimental results on the mechanical, frictional, sonic, acoustic and transport properties of different rocks at different conditions are compiled. The data acquisition system in the virtual lab is linked to the complied experimental data. Structural and microstructural images of deformed rocks are up-loaded and linked to different deformation tests. The integration of the microstructural image and the deformation data allows the student to visualize how forces reshape the structure of the rock and change the physical properties. The virtual lab is built using the Game Engine. The geological background, outstanding questions related to the geological environment, and physical and mechanical concepts associated with the problem will be illustrated on the web portal. In addition, some web based data collection tools are available to collect student feedback and opinions on their learning experience. The virtual laboratory is designed to be an online education tool that facilitates interactive learning.; Virtual Deformation Laboratory

  2. Anatomy of gravitationally deformed slopes

    Science.gov (United States)

    Chigira, Masahiro; Yamasaki, Shintaro; Hariyama, Takehiro

    2010-05-01

    Deep-seated gravitational slope deformation is the deformation of rocks as well as slope surfaces, but the internal structures have not been well observed and described before. This is mainly due to the difficulty in obtaining undisturbed samples from underground. We analyzed the internal deformational structures of gravitationally deformed slopes by using high quality drilled cores obtained by hybrid drilling technique, which has been recently developed and can recover very fragile materials that could not be taken by the conventional drilling techniques. Investigated slopes were gravitationally deformed out-facing slopes of pelitic schist and shale. The slope surfaces showed deformational features of small steps, depressions, knobs, and linear depressions, but had no major main scarp and landslide body with well-defined outline. This is indicative of slow, deep-seated gravitational deformation. Most of these small deformational features are hidden by vegetations, but they are detected by using airborne laser scanner. Drilled cores showed that the internal deformation is dominated by the slip and tearing off along foliations. Slippage along foliations is conspicuous in pelitic schist: Pelitic schist is sheared, particularly along black layers, which are rich in graphite and pyrite. Graphite is known to be a solid lubricant in material sciences, which seems to be why shearing occurs along the black layers. Rock mass between two slip layers is sheared, rotated, fractured, and pulverized; undulation of bedding or schistosity could be the nucleation points of fracturing. Tearing off along foliations is also the major deformation mode, which forms jagged morphology of rock fragments within shear zones. Rock fragments with jagged surface are commonly observed in "gouge", which is very different from tectonic gouge. This probably reflects the low confining pressures during their formation. Microscopic to mesoscopic openings along fractures are commonly observed with fractures, which also suggests the low confining pressures. Vertical distribution of gravitational deformation with above features indicates that gravitational shear zones are nucleated in a distributed manner, then gradually connected to each other, and finally cut through the whole slope. This is the transition of gravitational mass rock creep to rock slide. First nucleation points seem to be controlled by the heterogeneity of rock properties. Thick black layers in pelitic schist, shale near thick sandstone beds in sedimentary rocks, were such nuclear points. The geometrical relationships between the distribution of fracture zones and the slope morphology suggest that they are formed in accordance to the valley incision and resultant slope destabilization.

  3. Effect of heat treatment on diffusion, internal friction, microstructure and mechanical properties of ultra-fine-grained nickel severely deformed by equal-channel angular pressing

    International Nuclear Information System (INIS)

    Severe plastic deformation via equal-channel angular pressing was shown to induce characteristic ultra-fast diffusion paths in Ni (Divinski et al., 2011). The effect of heat treatment on these paths, which were found to be represented by deformation-modified general high-angle grain boundaries (GBs), is investigated by accurate radiotracer self-diffusion measurements applying the 63Ni isotope. Redistribution of free volume and segregation of residual impurities caused by the heat treatment triggers relaxation of the diffusion paths. A correlation between the GB diffusion kinetics, internal friction, microstructure evolution and microhardness changes is established and analyzed in detail. A phenomenological model of diffusion enhancement in deformation-modified GBs is proposed

  4. Deformations of three-dimensional metrics

    Science.gov (United States)

    Pugliese, Daniela; Stornaiolo, Cosimo

    2015-03-01

    We examine three-dimensional metric deformations based on a tetrad transformation through the action the matrices of scalar field. We describe by this approach to deformation the results obtained by Coll et al. (Gen. Relativ. Gravit. 34:269, 2002), where it is stated that any three-dimensional metric was locally obtained as a deformation of a constant curvature metric parameterized by a 2-form. To this aim, we construct the corresponding deforming matrices and provide their classification according to the properties of the scalar and of the vector used in Coll et al. (Gen Relativ Gravit 34:269, 2002) to deform the initial metric. The resulting causal structure of the deformed geometries is examined, too. Finally we apply our results to a spherically symmetric three geometry and to a space sector of Kerr metric.

  5. Deformations of three-dimensional metrics

    CERN Document Server

    Pugliese, Daniela

    2014-01-01

    We examine three-dimensional metric deformations based on a tetrad transformation through the action the matrices of scalar fields. We describe by this approach to deformation the results obtained by Coll et al. in [1], where it is stated that any three--dimensional metric was locally obtained as a deformation of a constant curvature metric parameterized by a 2--form.To this aim, we construct the corresponding deforming matrices and provide their classification according to the properties of the scalar $\\sigma$ and of the vector $\\mathbf{s}$ used in [1] to deform the initial metric. The resulting causal structure of the deformed geometries is examined, too.Finally we apply our results to a spherically symmetric three geometry and to a space sector of Kerr metric.

  6. A study on nonlinear finite element analysis of laminated rubber bearings. Pt.1. Development of evaluation method for mechanical properties of laminated rubber bearings for horizontal base isolation system considering volumetric deformation of rubber material

    International Nuclear Information System (INIS)

    The purpose of this research is to develop the evaluation method for mechanical properties of laminated rubber bearings by nonlinear finite element method (FEM) considering the volumetric deformation of natural rubber material. Relationship between pressure and volumetric strain of the natural rubber is obtained from the volumetric tests and is introduced into user-subroutine of the FEM code (ABAQUS). Finite element analyses of natural rubber bearings (NRB) and the natural rubber bearing with lead plug (LRB) are carried out. The results may be summarized as follows; 1) Horizontal, vertical stiffness and effect of shear deformation on vertical stiffness of natural rubber bearings that have various shape are simulated with enough accuracy. 2) Horizontal and vertical stiffness of LRB are also simulated well. (author)

  7. Shell structures and chaos in deformed nuclei and large metallic clusters

    CERN Document Server

    Heiss, W D; Radu, S; Heiss, W D; Nazmitdinov, R G; Radu, S

    1994-01-01

    A reflection-asymmetric deformed oscillator potential is analysed from the classical and quantum mechanical point of view. The connection between occurrence of shell structures and classical periodic orbits is studied using the ''removal of resonances method'' in a classical analysis. In this approximation, the effective single particle potential becomes separable and the frequencies of the classical trajectories are easily determined. It turns out that the winding numbers calculated in this way are in good agreement with the ones found from the corresponding quantum mechanical spectrum using the particle number dependence of the fluctuating part of the total energy. When the octupole term is switched on it is found that prolate shapes are stable against chaos whereas spherical and oblate cases become chaotic. An attempt is made to explain this difference in the quantum mechanical context by looking at the distribution of exceptional points which results from the matrix structure of the respective Hamiltonian...

  8. Effect of thermal cycling and mechanical deformation on the superconducting properties of Ag/YBa2Cu3O7-x wires

    International Nuclear Information System (INIS)

    Preforms made by filling silver tubes with YBa2Cu3O7-x (YBCO) powder were drawn to obtain wires with diameters in the 0.25mm to 1.00mm range. Straight samples of these wires were sintered and oxygenated. The observed changes in Tc and Jc while the samples were thermally cycled or mechanically deformed are reported

  9. Deformations in N=14 isotones

    CERN Document Server

    Kanada-Enyo, Y

    2005-01-01

    Systematic analysis of deformations in neutron-rich N=14 isotones was done based on the method of antisymmetrized molecular dynamics. The property of the shape coexistence in $^{28}$Si, which is known to have the oblate ground state and the prolate excited states, was successfully described. The results suggest that the shape coexistence may occur also in neutron-rich N=14 nuclei as well as $^{28}$Si. It was found that the oblate neutron shapes are favored because of the spin-orbit force in most of N=14 isotones. $Q$ moments and $E2$ transition strengths in the neutron-rich nuclei were discussed in relation to the intrinsic deformations, and a possible difference between the proton and neutron deformations in $^{24}$Ne was proposed.

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

    Science.gov (United States)

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

    2009-06-01

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

  11. Deformation scheme effect on the properties of heat pipes of 12KH1MF steel, hardened by mechanical and heat treatments

    International Nuclear Information System (INIS)

    In the development, by the method of mechanical and heat treatment, of strenghening conditions for tubes from steel 12Kh1MF cold drawing and cold reducing are used at a uniform deformation factor of 11% but with materially different schemes of stress-strain state (different distributions and signs of strains and stresses). The greatest strenthening effect as regards to the ultimate stress and yield stress at a uniform deformation is obtained in the drawing. The poligonizing annealing makes for the levelling out of the drawn and reduced metal, the strength characteristics deteriorate to a greater degree for the drawn metal. The heat resisting characteristics of metal of drawn and reduced tubes at a test temperature of 540degC and high stresses (20-24kgs/mm2) are similar, the plasticity, however, being higher with then drawn tubes. At stresses close to the working ones, metal of the reduced tubes features longer time periods before failure. (author)

  12. The influence of the temperature of plastic deformation on the structure and mechanical properties of copper alloys CuCo2Be and CuCo1Ni1Be

    OpenAIRE

    W. Ozgowicz; B.Grzegorczyk

    2009-01-01

    Purpose: The aim of the paper is to determine the influence of temperature of plastic deformation on the structure and mechanical properties of copper alloy of the CuCo2Be and CuCo1Ni1Be during a tensile test applied on electrodes to welders.Design/methodology/approach: The tensile test of the investigated copper alloys was realized in the temperature range of 20-800°C with a strain rate of 1.2•10-3s–1 on the universal testing machine. Metallographic observations of the structure were carried...

  13. Effect of severe plastic deformation by torsion on the properties and structure of the Ni54Mn21Ga25 and Ni54Mn20Fe1Ga25 alloys

    Science.gov (United States)

    Kourov, N. I.; Pushin, V. G.; Korolev, A. V.; Marchenkov, V. V.; Marchenkova, E. B.; Kazantsev, V. A.; Weber, H. W.

    2011-01-01

    The effect of one-percent substitution of iron for manganese on the physical (magnetic, electrical, thermal, and galvanomagnetic) properties and the crystal structure of the Ni54Mn21Ga25 alloy has been investigated. It has been demonstrated that the deviation of the alloy composition from the stoichiometric composition Ni50Mn25Ga25 leads to the formation of a mixed ferromagnetic-antiferromagnetic state. The atomic disordering and nanostructuring of the alloys under investigation due to the severe plastic deformation by torsion in Bridgman anvils to sizes of 10-20 nm result in the suppression of reversible magnetically controlled shape memory effects.

  14. Prediction of exotic octupole excitation modes in superdeformed A ? 150 and A ? 190 nuclei: Bending, Banana and other modes

    International Nuclear Information System (INIS)

    Results of the first calculations aiming at determination of the exotic shape effects at large elongations are presented. After discussing some formal aspects of our generalised approach based on the deformed Woods-Saxon potential, the overall trends in the quantal (shell) effects leading to the deformation driving forces in terms of Y?=3,? multipole components are presented. Finally, the nuclei are identified in which (at least at a low spin limit) the predicted exotic shape effects should manifest themselves in the most pronounced way. 10 figs

  15. Deformations of chiral algebras

    OpenAIRE

    Tamarkin, Dimitri

    2003-01-01

    We start studying chiral algebras (as defined by A. Beilinson and V. Drinfeld) from the point of view of deformation theory. First, we define the notion of deformation of a chiral algebra on a smooth curve $X$ over a bundle of local artinian commutative algebras on $X$ equipped with a flat connection (whereas `usual' algebraic structures are deformed over a local artinian algebra) and we show that such deformations are controlled by a certain *-Lie algebra $\\mathfrak g$. The...

  16. Alar Rim Deformities.

    Science.gov (United States)

    Totonchi, Ali; Guyuron, Bahman

    2016-01-01

    The alar rim plays an important role in nasal harmony. Alar rim flaws are common following the initial rhinoplasty. Classification of the deformities helps with diagnosis and successful surgical correction. Diagnosis of the deformity requires careful observation of the computerized or life-sized photographs. Techniques for treatment of these deformities can easily be learned with attention to detail. PMID:26616701

  17. Deformations in quantum mechanics

    International Nuclear Information System (INIS)

    We consider deformations of quantum mechanical objects, and use the novel construction of warped convolutions for deformation. It turns out that through the deformation we are able to obtain several quantum mechanical effects where electromagnetic fields play a role. We understand the magnetic field as an object which is the outcome of strict mathematical deformation. Furthermore, we are able to obtain all magnetic fields by using this method of deformation. The results are used in quantum field theory to obtain an effective quantum plane.

  18. Deformations in quantum physics

    International Nuclear Information System (INIS)

    We consider deformations of quantum mechanical objects, and use the novel construction of warped convolutions for deformation. It turns out that through the deformation we are able to obtain several quantum mechanical effects where electromagnetic fields play a role. We understand the magnetic field as an object which is the outcome of strict mathematical deformation. Furthermore, we are able to obtain all magnetic fields by using this method of deformation. The results are used in quantum field theory to obtain an effective quantum plane.

  19. Effect of hydroextrusion pressure on the mechanism of molybdenum monocrystals plastic deformation

    International Nuclear Information System (INIS)

    Considered are plastic deformation peculiarities of molybdenum monocrystals in the process of multiple-stage and single-stage deformation by hydroextrusion at 20-80% reduction under pressures of 1000-11000 atm. The effect of hydrostatic extrusion pressure upon the plastic deformation mechanism and mechanical properties is established. Multiple-stage deformation permits to considerably decrease the pressure value in practice as compared with the single-stage hydroextrusion, without deterioration of properties of deformed molybdenum monocrystals

  20. Time-resolved soft-x-ray spectroscopy of a magnetic octupole transition in nickel-like xenon, cesium, and barium ions

    Energy Technology Data Exchange (ETDEWEB)

    Trabert, E; Beiersdorfer, P; Brown, G V; Boyce, K; Kelley, R L; Kilbourne, C A; Porter, F S; Szymkowiak, A

    2005-11-11

    A microcalorimeter with event mode capability for time-resolved soft-x-ray spectroscopy, and a high-resolution flat-field EUV spectrometer have been employed at the Livermore EBIT-I electron beam ion trap for observations and wavelength measurements of M1, E2, and M3 decays of long-lived levels in the Ni-like ions Xe{sup 26+}, Cs{sup 27+}, and Ba{sup 28+}. Of particular interest is the lowest excited level, 3d{sup 9}4s {sup 3}D{sub 3}, which can only decay via a magnetic octupole (M3) transition. For this level in Xe an excitation energy of (590.40 {+-} 0.03eV) and a level lifetime of (11.5 {+-} 0.5 ms) have been determined.

  1. Deformation-driving properties of the ?i/sub 13/2/[660]1/2+ intruder orbital for A?130 nuclei

    International Nuclear Information System (INIS)

    Several rotational-band structures have recently been observed in mass A?130 nuclei, built on multiquasiparticle states of enhanced quadrupole deformation, the so-called superdeformed states (??0.4). In /sup 137/Sm, a decoupled band built on the ?i/sub 13/2/[660](1/2+ single-quasineutron orbital, intruding from two oscillator shells above with a predicted ??0.35, was observed to low spin and excitation energy. The role of this ?-driving ?i/sub 13/2/ orbital, which showed a 50% enhanced moment of inertia, is discussed in terms of the superdeformation in this mass region

  2. IBA in deformed nuclei

    International Nuclear Information System (INIS)

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

  3. Neptunium octupole and hexadecapole motifs in NpO2 directly from electric dipole (E1) enhanced x-ray Bragg diffraction

    International Nuclear Information System (INIS)

    The phase transition in NpO2 at T0 ? 25.5 K is accompanied by the onset of superlattice reflections in the x-ray Bragg diffraction pattern, with intensity enhanced by an electric dipole (E1) event. Additional experiments using other techniques indicate no ordering at T0 of Np magnetic moments. Absence of long-range magnetic order below T0 fits with the outcome of a polarization analysis of superlattice intensities at 12 K; signals are observed in both the unrotated (?'?) and rotated (?'?) channels of scattering while magnetic (dipole) moments would contribute only in the rotated channel. We demonstrate that these empirical findings, together with a narrow energy profile of the Bragg intensity at the Np M4 edge, are consistent with magnetic and charge contributions to the E1 Bragg amplitude described by Np 5f multipoles of ranks 3 (octupole) and 4 (hexadecapole). Key to our understanding of the x-ray diffraction data gathered in the vicinity of the Np M4 edge is recognition of an exchange field creating 3d3/2 core-level structure. The particular importance of the exchange field at the Np M4 edge is emphatically revealed in calculations of the corresponding x-ray absorption spectrum with and without the core-valence interaction. From the experimental information about NpO2 we can infer a ground-state wavefunction for the Np 5f3 valence shell and estimate saturation values for the octupole and hexadecapole. We are led to null values for Np multipoles of ranks 2 (quadrupole) and 5 (triakontadipole)

  4. Deformation of C15 Laves phase alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chu, F.; Pope, D.P.

    1995-12-31

    Details of the structure and previous work on the deformation of C Laves phases are reviewed. The phase diagram of the Hf-V-Nb system, some metallurgical and physical properties, mechanical behavior, and the deformation mechanisms of HfV{sub 2}+Nb (CI5 HfV{sub 2}+Nb and V-rich bcc solution) are presented based on our previous work. Theoretical approaches to understanding the results of these studies are discussed.

  5. Thermal conductivity of deformed carbon nanotubes

    OpenAIRE

    Zhong, Wei-Rong; Zhang, Mao-Ping; Zheng, Dong-Qin; Ai, Bao-Quan

    2011-01-01

    We investigate the thermal conductivity of four types of deformed carbon nanotubes by using the nonequilibrium molecular dynamics method. It is reported that various deformations have different influence on the thermal properties of carbon nanotubes. For the bending carbon nanotubes, the thermal conductivity is independent on the bending angle. However, the thermal conductivity increases lightly with XY-distortion and decreases rapidly with Z-distortion. The thermal conducti...

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

    Science.gov (United States)

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

    2011-12-01

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

  7. Diffeomorphic Statistical Deformation Models

    DEFF Research Database (Denmark)

    Hansen, Michael Sass; Hansen, Mads/Fogtman; Larsen, Rasmus

    2007-01-01

    In this paper we present a new method for constructing diffeomorphic statistical deformation models in arbitrary dimensional images with a nonlinear generative model and a linear parameter space. Our deformation model is a modified version of the diffeomorphic model introduced by Cootes et al. The modifications ensure that no boundary restriction has to be enforced on the parameter space to prevent folds or tears in the deformation field. For straightforward statistical analysis, principal compo...

  8. -Deformed nonlinear maps

    Indian Academy of Sciences (India)

    Ramaswamy Jaganathan; Sudeshna Sinha

    2005-03-01

    Motivated by studies on -deformed physical systems related to quantum group structures, and by the elements of Tsallis statistical mechanics, the concept of -deformed nonlinear maps is introduced. As a specific example, a -deformation procedure is applied to the logistic map. Compared to the canonical logistic map, the resulting family of -logistic maps is shown to have a wider spectrum of interesting behaviours, including the co-existence of attractors – a phenomenon rare in one-dimensional maps.

  9. Deformable Simplicial Complexes

    DEFF Research Database (Denmark)

    Misztal, Marek Krzysztof

    In this dissertation we present a novel method for deformable interface tracking in 2D and 3D|deformable simplicial complexes (DSC). Deformable interfaces are used in several applications, such as fluid simulation, image analysis, reconstruction or structural optimization. In the DSC method, the...... triangles/tetrahedra marked as outside from those marked as inside. Such an approach allows for robust topological adaptivity. Among other advantages of the deformable simplicial complexes there are: space adaptivity, ability to handle and preserve sharp features, possibility for topology control. We...

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

    International Nuclear Information System (INIS)

    Long-term creep rupture strengths and the microstructural stability of ASME P92 and P122 pipes have been studied using creep testing at the temperatures from 550 to 700 deg. C and detailed scanning transmission electron microscopy. Creep rupture strength of P92 is found to be more stable than that of P122 at temperatures over 600 deg. C, which is mainly due to the difference in their Cr content. P122 type model steel with reduced Cr content, 9%Cr, has been prepared to explore the effect of Cr on the stability of MX and formation of Z-phase during creep deformation. MX in 9%Cr steel is found to be stable even after prolonged exposure at 650 deg. C, while Cr and Fe concentration to MX without marked coarsening has been observed in 10.5%Cr steel after aging for 10,000 h at 650 deg. C. This seems to lead to the transition of MX carbonitride into the Z-phase after aging for 23,000 h, which requires ordering in a M2N lattice to achieve a tetragonal Z-phase to be stable. Creep deformation behavior in the transient creep region of the steels is almost same up to about 7000 h, while in the acceleration creep region the creep rate of 10.5%Cr steel becomes much faster than that of 9%Cr steel, resulting in shorter rupture life. It is obvious that the creep rupture strength degradation starts prior to the formation of Z-phase in 10.5%Cr steel. It is thus concluded that Z-phase is not a necessary factor for degradation of creep rupture strength but the instability of the fine precipitates such as Cr2(C, N) caused by the compositions change like Cr supply to MX carbonitride is more essential.

  11. Periodic orbit approach to prolate dominance in nuclear deformation

    International Nuclear Information System (INIS)

    Semiclassical origin of deformed nuclear shell structures are investigated. In the periodic orbit theory, quantum level density is expressed as the sum over classical periodic orbits, and properties of shell structures can be analyzed in terms of short periodic orbits. In particular, we focus on the role of periodic orbit bifurcations which are responsible for exotic deformed shell structures found at certain values of deformation parameters. We show that the prolate shape dominance in nuclear deformations can be clearly understood from deformed shell structures caused by periodic orbits and their bifurcations in realistic nuclear mean field potential models.

  12. An extended deformable shell model for ionic crystals including quadrupolar deformation of the charge cloud

    International Nuclear Information System (INIS)

    It is well known that the dipolar and scalar deformation of the charge cloud around an ion in ionic crystals are quite significant in describing the different lattice mechanical properties. Even after the inclusion of the above deformations systematic discrepancies between theory and experiment persist. An attempt is made to incorporate the effect of the quadrupolar distortion of the charge cloud in the framework of the deformable shell model. All the relevant equations and lattice sums are evaluated for the CsCl structure and a preliminary application of the complete model which takes into account simultaneously the scalar, the dipolar and the quadrupolar deformation considered for a CsCl structure crystal. So far there is no estimate of the effect of the quadrupolar distortion on the different properties of a crystal belonging to CsCl structure. The calculation indicates that the effect is quite considerable for certain properties and its inclusion improves the overall agreement with experiment. (author)

  13. Performance through Deformation and Instability

    Science.gov (United States)

    Bertoldi, Katia

    2015-03-01

    Materials capable of undergoing large deformations like elastomers and gels are ubiquitous in daily life and nature. An exciting field of engineering is emerging that uses these compliant materials to design active devices, such as actuators, adaptive optical systems and self-regulating fluidics. Compliant structures may significantly change their architecture in response to diverse stimuli. When excessive deformation is applied, they may eventually become unstable. Traditionally, mechanical instabilities have been viewed as an inconvenience, with research focusing on how to avoid them. Here, I will demonstrate that these instabilities can be exploited to design materials with novel, switchable functionalities. The abrupt changes introduced into the architecture of soft materials by instabilities will be used to change their shape in a sudden, but controlled manner. Possible and exciting applications include materials with unusual properties such negative Poisson's ratio, phononic crystals with tunable low-frequency acoustic band gaps and reversible encapsulation systems.

  14. Relativistic description of deformed nuclei

    International Nuclear Information System (INIS)

    The author has shown that relativistic Hartree calculations using parameters that have been fit to the properties of nuclear matter can provide a good description of both spherical and axially deformed nuclei. The quantitative agreement with experiment is equivalent to that which was obtained in non-relativistic calculations using Skyrme interactions. The equilibrium deformation is strongly correlated with the size of the spin-orbit splitting, and that parameter sets which give roughly the correct value for this splitting provide the best agreement with the quadrupole moments in the s-d shell. Finally, for closed shell +/- 1 nuclei, it was shown that the self-consistent calculations are able to reproduce the experimental magnetic moments. This was not possible in relativistic calculations which include only the effects of the valence orbital

  15. q-Deformed Schroedinger equation

    International Nuclear Information System (INIS)

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

  16. Greenland Analogue Project - Hydraulic properties of deformation zones and fracture domains at Forsmark, Laxemar and Olkiluoto for usage together with Geomodel version 1

    Energy Technology Data Exchange (ETDEWEB)

    Follin, Sven (SF GeoLogic AB (Sweden)); Stigsson, Martin (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)); Rhen, Ingvar (Sweco Environment AB (Sweden)); Engstroem, Jon (Geologian tutkimuskeskus (Finland)); Klint, Knut Erik (De Nationale Geologiske Undersoegelser for Danmark og Groenland (Denmark))

    2011-05-15

    The database of the GAP site is under development. In order to meet the data needs of the different modelling teams working with groundwater flow modelling it has been decided to compile trial data sets comprising structural-hydraulic properties suitable for flow modelling on different scales. The properties provided in this report are based on data and groundwater flow modelling studies conducted for three sites located in the Fennoscandian Shield, two of which are studied by SKB, Forsmark and Laxemar, and one by Posiva, Olkiluoto. The provided hydraulic properties provided here are simplified to facilitate a readily usage together with the GAP Geomodel version 1.

  17. Resurgent deformation quantisation

    Energy Technology Data Exchange (ETDEWEB)

    Garay, Mauricio, E-mail: garay91@gmail.com [Institut für Mathematik, FB 08 Physik, Mathematik und Informatik, Johannes Gutenberg-Universität, 55099 Mainz (Germany); Goursac, Axel de, E-mail: Axelmg@melix.net [Chargé de Recherche au F.R.S.-FNRS, IRMP, Université Catholique de Louvain, Chemin du Cyclotron, 2, B-1348 Louvain-la-Neuve (Belgium); Straten, Duco van, E-mail: straten@mathematik.uni-mainz.de [Institut für Mathematik, FB 08 Physik, Mathematik und Informatik, Johannes Gutenberg-Universität, 55099 Mainz (Germany)

    2014-03-15

    We construct a version of the complex Heisenberg algebra based on the idea of endless analytic continuation. The algebra would be large enough to capture quantum effects that escape ordinary formal deformation quantisation. -- Highlights: •We construct resurgent deformation quantisation. •We give integral formulæ. •We compute examples which show that hypergeometric functions appear naturally in quantum computations.

  18. Secondary deformation of molybdenum

    International Nuclear Information System (INIS)

    The features of secondary deformation of molybdenum with initially produced dislocation structure are studied. It is shown that any prestrained deformation can be represented using two additional parameters-equivalent strain eeq and effective grain size deff. Application of these parameters in practice of thermomechanical treatment allows to produce the micron size grain

  19. Resurgent deformation quantisation

    International Nuclear Information System (INIS)

    We construct a version of the complex Heisenberg algebra based on the idea of endless analytic continuation. The algebra would be large enough to capture quantum effects that escape ordinary formal deformation quantisation. -- Highlights: •We construct resurgent deformation quantisation. •We give integral formulæ. •We compute examples which show that hypergeometric functions appear naturally in quantum computations

  20. Models of the Dynamic Deformations of Polymers

    Science.gov (United States)

    Merzhievsky, Lev; Voronin, Mihail; Korchagina, Anna

    2013-06-01

    In the process of deformation under the influence of external loading polymeric mediums show the complicated behavior connected with features of their structure. For amorphous polymers distinguish three physical conditions - glasslike, highlyelastic and viscoplastic. To each of the listed conditions there corresponds to mikro - meso- and macrostructural mechanisms of irreversible deformation. In the report the review of results of construction of models for the description of dynamic and shock-wave deformation of the polymers which are based on developed authors representations about mechanisms of irreversible deformation is made. Models include the formulation of the equations of conservation laws, considering effect of a relaxation of shear stresses in the process of deformation. For closing of models the equations of states with nonspherical tensor of deformations and relation for time of a relaxation of shear stresses are constructed. With using of the formulated models a number of problems of dynamic and shock wave deformations has been solved. The results are compared with corresponding experimental date. Development of the used approach are in summary discussed. To taking into account memory and fractal properties of real polymers is supposed of derivatives and integrals of a fractional order to use. Examples of constitutive equations with derivatives of a fractional order are presented. This work is supported by the Integration project of the Siberian Branch of the Russian Academy of Science 64 and grant RFBR 12-01-00726.