Octupole deformation properties of the Barcelona-Catania-Paris energy density functionals
Robledo, L M; Schuck, P; Viñas, X
2010-01-01
We discuss the octupole deformation properties of the recently proposed Barcelona-Catania-Paris (BCP) energy density functionals for two sets of isotopes, those of radium and barium, where it is believed that octupole deformation plays a role in the description of the ground state. The analysis is carried out in the mean field framework (Hartree- Fock- Bogoliubov approximation) by using the axially symmetric octupole moment as a constraint. The main ingredients entering the octupole collective Hamiltonian are evaluated and the lowest lying octupole eigenstates are obtained. In this way we restore, in an approximate way, the parity symmetry spontaneously broken by the mean field and also incorporate octupole fluctuations around the ground state solution. For each isotope the energy of the lowest lying $1^{-}$state and the $B(E1)$ and $B(E3)$ transition probabilities have been computed and compared to both the experimental data and the results obtained in the same framework with the Gogny D1S interaction, which...
Microscopic study of octupole-deformations in even-even 226-230Th isotopes
International Nuclear Information System (INIS)
Study of octupole correlations in the actinides has attracted interest because of the predictions that octupole deformation would be present in the Z ? 88 and N ?134 region. These predictions have been explored through a series of experimental studies, which have centred on energy spectra and transition properties. In the present work, the octupole-octupole interaction is incorporated to the pairing plus quadrupole-quadrupole model. The microscopic Cranked Hartree Bogoliubov framework (CHB) is employed with pairing plus quadrupole-quadrupole plus octupole-octupole interaction to study the non-axial nature of 226-230Th.
Stable octupole deformation in some actinide nuclei
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The possibilities of permanent octupole deformation in the ground state of 222Ra, 222Rn and 224Ra nuclei is studied using the constrained HF + BCS method and the Gogny density dependent interaction. The calculation shows energy minima for non-zero values of octupole moment for all three nuclei studied, the minimum for 222Rn being shallower than for the others. This result is in agreement with the observed position of I?=1- states. The dipole moments for these nuclei are also calculated. (orig.)
Octupole Deformed Nuclei in the Actinide Region
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.
Bonatsos, Dennis; Minkov, N; Karampagia, S; Petrellis, D
2015-01-01
The analytic quadrupole octupole axially symmetric model, which had successfully predicted 226Ra and 226Th as lying at the border between the regions of octupole deformation and octupole vibrations in the light actinides using an infinite well potential (AQOA-IW), is made applicable to a wider region of nuclei exhibiting octupole deformation, through the use of a Davidson potential (AQOA-D). Analytic expressions for energy spectra and B(E1), B(E2), B(E3) transition rates are derived. The spectra of 222-226Ra and 224,226Th are described in terms of the two parameters phi_0 (expressing the relative amount of octupole vs. quadrupole deformation) and beta_0 (the position of the minimum of the Davidson potential), while the recently determined B(EL) transition rates of 224Ra, presenting stable octupole deformation, are successfully reproduced. A procedure for gradually determining the parameters appearing in the B(EL) transitions from a minimum set of data, thus increasing the predictive power of the model, is out...
The Structure of Heavy Octupole and Superheavy Quadrupole Deformed Nuclei
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We report here experimental attempts to determine the sign of the electric dipole moment (relative to the electric octupole moment) in the octupole deformed nucleus 226Ra. Sensitivity to this quantity is observed in the measured yields of ?-ray transitions following very low energy Coulomb excitation. Recent progress is also reported in the development of new spectroscopic techniques that promise to elucidate the structure of deformed superheavy nuclei in the region of 254No. The 4+?2+ transition in 254No as well as higher spin transitions, has been identified using recoil-tagged conversion electron spectroscopy. (author)
Periodic orbits and shell structure in octupole deformed potentials
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The effect of an octupole term in a quadrupole deformed single-particle potential is studied from the classical and quantum-mechanical viewpoint. Whereas the problem is nonintegrable, the quantum-mechanical spectrum nevertheless shows some shell structure in the superdeformed prolate case for particular, yet fairly large octupole strengths; for spherical or oblate deformation the shell structure disappears. This result is associated with classical periodic orbits that are found by employing the removal of resonances method; this approximation method allows determination of the shape of the orbit and of the approximate octupole coupling strength for which it occurs. The validity of the method is confirmed by solving numerically the classical equations of motion. The quantum-mechanical shell structure is analyzed using the particle-number dependence of the fluctuating part of the total energy. In accordance with the classical result, this dependence turns out to be very similar for a superdeformed prolate potential plus octupole term and a hyperdeformed prolate potential without octupole term. In this way the shell structure is explained at least for some few hundred levels. The Fourier transform of the level density further corroborates these findings
Collective motion of a pure octupole deformed system
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The collective motion of a pure octupole deformed system is treated as the vibrations in body-fixed frame and rotation of this system about the axes of lab-system, as well as the coupling between vibrations and rotation. The quantized operator of kinetic energy is derived and the collective spectra built on some special equilibrium shapes are discussed
Studies of Stable Octupole Deformations in the Radium Region
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. \\...
Nuclear fusion as a probe for octupole deformation in $^{224}$Ra
Kumar, Raj; Vitturi, A
2015-01-01
$\\textit{Background}$: Nuclear fusion has been shown to be a perfect 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 stactic octupole deformation in nuclei will enhanced a possible permanent electric dipole moment, leading to a possible demonstration of parity violation. $\\textit{Purpose}$: To check whether static octupole deformation or octupole vibration in fusion give qualitatively different results so that both situations can be experimentally disentangled. $\\textit{Method}$: Fusion cross sections are computed in the Coupled-Channels formalism making use of the Ingoing-Wave Boundary Conditions (IWBC) for the systems $^{16}$O+$^{144}$Ba and $^{16}$O+$^{224}$Ra. $\\textit{Results}$: Barrier distributions of the two considered schemes show different patterns. For the $^{224}$Ra case, the octupole deformation parameter is large enough to create a sizeable difference. $\\textit{Con...
Self-consistent calculation of the quadrupole-octupole deformation energy surface of 222Ra
International Nuclear Information System (INIS)
The Hartree-Fock + BCS quadrupole-octupole deformation energy surface of 223Ra, calculated with the Skyrme SIII interaction, presents a minimum for a non-zero value of the octupole moment. Our results suggest the existence of a quadrupole coupling which may account for the observed differences between the moments of inertia of the positive- and negative-parity bands. (orig.)
Octupole deformation for Ba isotopes in a reflection-asymmetric relativistic mean-field approach
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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)
Microscopic and semi-classical treatments of octupole deformation in the light actinides
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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
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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
Gamma-ray spectroscopy in the region of octupole deformation near Z = 90
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The nuclei sup(220)Ra and sup(223)Th were populated by the reaction sup(18)O + sup(208)Pb at a beam energy of 83 MeV. In sup(220)Ra the positive parity members of the yrast band were identified to Jsup(?)=12sup(+) and the negative parity members from Jsup(?)=5sup(-) to Jsup(?)=11sup(-). The alternating positive and negative parity levels are strongly coupled by E1 transitions. The sequence of levels observed and the large ratios of B(E1)/B(E2) suggest that the nuclei in this mass region have a stable octupole deformation. (author)
Study of octupole deformation in n-rich Ba isotopes populated via $\\beta$-decay
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.
Identification of excited states and evidence for octupole deformation in sup 2 sup 2 sup 6 U
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...
Identification of Excited States in 226U: Evidence for Octupole Deformation
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The level scheme of 226U has been deduced from the results of two experiments carried out at the University of Jyvaskyla, Finland. Both ?- and ?-ray-spectroscopic techniques have been employed. The interleaved states of positive- and negative-parity indicate the octupole nature of this nucleus, and the behavior of the difference in aligned angular momentum between the positive- and negative-parity bands as a function of rotational frequency is consistent with that expected for a rotating reflection-asymmetric shape
Octupole shaps in nuclei, and some rotational consequences thereof
International Nuclear Information System (INIS)
During the last years a large number of experimental papers presenting spectroscopic evidence for collective dipole and octupole deformations have appeared. Many theoretical attempts have been made to explain the observed spectroscopic properties in terms of stable octupole deformations. The coupling by the octupole potential, being proportional to Y30, is strongest for those subshells for which ?1 = 3. Therefore the tendency towards octupole deformation occurs just beyond closed shells where the high-j intruder subshells (N,1,j) lie very close to the normal parity subshells (N-1,1-3,j-3), i.e. for the particle numbers 34 (g/sub 9/2/-p/sub 3/2/), 56 (h/sub 11/2/-d/sub 5/2/). 9C (i/sub 13/2/-f/sub 7/2/) and 134 (j/sub 15/2/-g/sub 9/2/). Empirically, it is specifically for the particle numbers listed above that negative parity states are observed at relatively low energies in doubly even nuclei. From the different combinations of octupole-driving particle numbers four regions of likely candidates for octupole deformed equilibrium shapes emerge, namely the neutron-deficient nuclei with Z approx. = 90, N approx. = 134 (light actinides) and Z approx. = 34, N approx. = 34 (A approx. = 70) and the neutron-rich nuclei with Z approx. = 56, N approx. = 90 (heavy Ba) and Z approx. = 34, N56 (A approx. = 90). In our calculations we searched for octupole unstable nuclei in these four mass regions. The Strutinsky method with the deformed Woods-Saxon potential was employed. The macroscopic part consists of a finite-range liquid drop energy, where both the surface and Coulomb terms contain a diffuseness correction
Octupole correlations in the heavy elements
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The effects of octupole correlations on the nuclear structure of the heavy elements are discussed. The cluster model description of the heavy elements is analyzed. The relevance of 26-pole deformation and fast El transitions to an octupole model is considered. 30 refs., 21 figs., 1 tab
Microscopic analysis of the octupole phase transition in Th isotopes
Nomura, K; Lu, B -N
2013-01-01
A shape phase transition between stable octupole deformation and octupole vibrations in Th nuclei is analyzed in a microscopic framework based on nuclear density functional theory. The relativistic functional DD-PC1 is used to calculate axially-symmetric quadrupole-octupole constrained energy surfaces. Observables related to order parameters are computed using an interacting-boson Hamiltonian, with parameters determined by mapping the microscopic energy surfaces to the expectation value of the Hamiltonian in the boson condensate. The systematics of constrained energy surfaces and low-energy excitation spectra point to the occurrence of a phase transition between octupole-deformed shapes and shapes characterized by octupole-soft potentials.
Evidence for an octupole rotational band in 74Se
International Nuclear Information System (INIS)
From in-beam ?-ray spectroscopy in 74Se, a negative-parity band to (11-) with rotational properties built on a 3- collective octupole state is established along with the positive-parity (Barrette et al.) yrast band to (14+). The negative-parity band has essentially a constant moment of inertia in sharp constrast to the positive-parity band. This is the first negative-parity band outside those in deformed nuclei with such pure rotational behavior
Giant Octupole Resonance Simulation
Walke, R; Walke, Rainer; Morawetz, Klaus
1999-01-01
Using a pseudo-particle simulation technique we simulate large amplitude isoscalar giant octupole excitations in a finite nuclear system. Dependent on the initialization we can either observe clear octupole modes or over-damped octupole modes which decay immediately into quadrupole ones. We propose that octupole modes should be observed in central asymmetric collisions of heavy ions with mass relation 3:7.
Simultaneous quadrupole and octupole shape phase transitions in Thorium
Li, Z. P.; Song, B. Y.; Yao, J. M.; Vretenar, D.; Meng, J.
2013-01-01
The evolution of quadrupole and octupole shapes in Th isotopes is studied in the framework of nuclear Density Functional Theory. Constrained energy maps and observables calculated with microscopic collective Hamiltonians indicate the occurrence of a simultaneous quantum shape phase transition between spherical and quadrupole-deformed prolate shapes, and between non-octupole and octupole-deformed shapes, as functions of the neutron number. The nucleus $^{224}$Th is closest to...
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
Non-axial Octupole Deformations of $N=Z$ Nuclei in $A \\sim 60-80$ Mass Region
Matsuo, M; Yabana, K
1998-01-01
By performing a fully three dimensional Hartree-Fock calculation with use of the Skyrm forces, we demonstrate possibility of exotic deformations violating both the reflection and the axial symmetries of N=Z nuclei in $A \\sim 60-80$ mass region. The \\Ytwo tetrahedral shape predicted in excited \\Zr arises from a shell gap at $N,Z = 40$ which is enhanced for the tetrahedron deformation. Softness toward the \\Ythree triangular deformation of the oblate state in \\Se is also predicted.
Simultaneous quadrupole and octupole shape phase transitions in Thorium
Li, Z P; Yao, J M; Vretenar, D; Meng, J
2013-01-01
The evolution of quadrupole and octupole shapes in Th isotopes is studied in a fully microscopic framework based on nuclear Density Functional Theory. The constrained potential energy maps and observables calculated with microscopic collective Hamiltonians, indicate the occurrence of a simultaneous quantum shape phase transition between spherical and quadrupole-deformed prolate shapes, and between non-octupole and octupole-deformed shapes, as functions of the nucleon number. $^{224}$Th is predicted closest to the critical point of the double phase transition. A microscopic mechanism of this phenomenon is discussed in terms of the evolution of single-nucleon orbitals with deformation.
Simultaneous quadrupole and octupole shape phase transitions in Thorium
Energy Technology Data Exchange (ETDEWEB)
Li, Z.P.; Song, B.Y.; Yao, J.M. [School of Physical Science and Technology, Southwest University, Chongqing 400715 (China); Vretenar, D. [Physics Department, Faculty of Science, University of Zagreb, 10000 Zagreb (Croatia); Kavli Institute for Theoretical Physics China, CAS, Beijing 100190 (China); Meng, J., E-mail: mengj@pku.edu.cn [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); Department of Physics, University of Stellenbosch, Stellenbosch (South Africa)
2013-11-04
The evolution of quadrupole and octupole shapes in Th isotopes is studied in the framework of nuclear Density Functional Theory. Constrained energy maps and observables calculated with microscopic collective Hamiltonians indicate the occurrence of a simultaneous quantum shape phase transition between spherical and quadrupole-deformed prolate shapes, and between non-octupole and octupole-deformed shapes, as functions of the neutron number. The nucleus {sup 224}Th is closest to the critical point of a double phase transition. A microscopic mechanism of this phenomenon is discussed in terms of the evolution of single-nucleon orbitals with deformation.
Electron scattering from the octupole band in 238U
International Nuclear Information System (INIS)
A simple model for nuclear surface vibrations in permanently deformed nuclei does well in reproducing electron scattering cross sections of rotational levels built on a K/sup ?/= 0- intrinsic octupole vibration in 238U
Microscopic analysis of quadrupole-octupole shape evolution
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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.
International Nuclear Information System (INIS)
E1, E2 and E3 matrix elements have been determined for transitions between states up to spin 13 in 148Nd. These values were obtained from Coulomb excitation data using 58Ni and 92Mo ions, projectile excitation using a 208Pb target, and from recoil distance lifetime measurements. The results are consistent with a description of 148Nb having fairly constant intrinsic-frame moments of Q20 = +400 efm2 (?2rms ?+0.22), Q30sum ?1600 efm3 (?3rms ?0.16) for the positive parity states and Q20 =+330 efm2 (?2rms ?+0.18), Q30sum ?2000 efm3 (?3rms ?0.21) for the negative parity states. (author). 23 refs., 3 figs
Rodríguez-Guzmán, R.; Robledo, Luis Miguel; Sarriguren, Pedro
2012-01-01
The interplay between the collective dynamics of the quadrupole and octupole deformation degree of freedom is discussed in a series of Sm and Gd isotopes both at the mean-field level and beyond, including parity symmetry restoration and configuration mixing. Physical properties such as negative-parity excitation energies and E1 and E3 transition probabilities are discussed and compared to experimental data. Other relevant intrinsic quantities such as dipole moments, ground-state quadrupole mo...
Improvements on the present theoretical understanding of octupole correlations
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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.
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.
Octupole correlation effects in nuclei
International Nuclear Information System (INIS)
Octupole correlation effects in nuclei are discussed from the point of view of many-body wavefunctions as well as mean-field methods. The light actinides, where octupole effects are largest, are considered in detail. Comparisons of theory and experiment are made for energy splittings of parity doublets; E1 transition matrix elements and one-nucleon transfer reactions
Quadrupole and octupole collectivity in 148Nd
International Nuclear Information System (INIS)
The role of quadrupole and octupole collectivity in the shape-transitional nucleus 148Nd has been studied by Coulomb excitation using beams of 58Ni and 92Mo, and a beam of 148Nd (using a 208Pb target). The extracted E1, E2 and E3 matrix elements involving states up to 12+ in the ground band and 13- in the negative-parity band are presented, and compared to calculations that assume a vibrational and rotational octupole nature for the negative-parity band. The positive-parity ground-band states are well described in terms of a prolate deformed shape with Q20?400 e fm2 (?2rms?+0.18). The present results suggest a vibrational octupole nature for the low-spin negative-parity states, with an intrinsic moment Q30?1500 e fm3 (?3rms?0.12). The E2 and E3 matrix elements connecting these bands to the ?- and ?-vibrational bands (and within these bands) are also presented, and compared to calculations incorporating the coupling between the rotational and vibrational modes. These calculations describe reasonably well the E2 matrix elements involving the gamma band, but do not reproduce the measured E2 matrix elements for the beta band, implying a complicated intrinsic structure for the beta band. The strong enhancement of the measured E3 matrix elements connecting the negative-parity band to the beta band coarity band to the beta band could be indicative of a significant component of the two-phonon octupole vibration in the wavefunction of the so-called beta band. (orig.)The role of quadrupole and octupole collectivity in the shape-transitional nucleus 148Nd has been studied by Coulomb excitation using beams of 58Ni and 92Mo, and a beam of 148Nd (using a 208Pb target). The extracted E1, E2 and E3 matrix elements involving states up to 12+ in the ground band and 13- in the negative-parity band are presented, and compared to calculations that assume a vibrational and rotational octupole nature for the negative-parity band. The positive-parity ground-band states are well described in terms of a prolate deformed shape with Q20?400 e fm2 (?2rms?+0.18). The present results suggest a vibrational octupole nature for the low-spin negative-parity states, with an intrinsic moment Q30?1500 e fm3 (?3rms?0.12). The E2 and E3 matrix elements connecting these bands to the ?- and ?-vibrational bands (and within these bands) are also presented, and compared to calculations incorporating the coupling between the rotational and vibrational modes. These calculations describe reasonably well the E2 matrix elements involving the gamma band, but do not reproduce the measured E2 matrix elements for the beta band, implying a complicated intrinsic structure for the beta band. The strong enhancement of the measured E3 matrix elements connecting the negative-parity band to the beta band c
Structure and properties of copper deformed by severe plastic deformation methods
M. Richert; J. Richert; A. Hotlo?; W. Pachla; J. Skiba
2011-01-01
Purpose: The main object of this study is to establish the influence of severe plastic deformation on the microstructure evolution and properties of polycrystalline copper Cu99.99.Design/methodology/approach: Polycrystalline copper Cu99.99 was deformed by cyclic extrusion compression (CEC), equal channel angular pressing (ECAP) and hydrostatic extrusion (HE). Additionally the combination of these methods were applying to the sample deformations. The microstructure and properties of samples a...
Inelastic alpha scattering studies of the low-energy octupole resonance
International Nuclear Information System (INIS)
Beams of 96 and 115 MeV ? particles have been used to study the distribution of isoscalar octupole strength in 18 nuclei from 40Ca to 208Pb. A prominent broad peak (GAMMA approx. 2.5 MeV) is observed at E/sub x/ approx. 30/A/sup 1/3/ MeV in nuclei from 66Zn to 197Au. No broad peak is observed in this excitation energy range in 208Pb or 40Ca and lighter nuclei. The oscillatory angular distributions of the (?,?') reaction exciting this peak are in excellent agreement with l = 3 distorted-wave Born approximation calculations. Studies of the angular range from sigma/sub lab/ = 3.50 to 60 in 116Sn indicate very little contribution from l = 1 strength. Energy- weighted sum rule fractions for this low-energy octupole resonance are generally in the range from 15% to 20%; this corresponds to 1/2 to 2/3 of the expected 1h? octupole strength. The overall distribution of octupole strength in spherical nuclei, including the absence of the low-energy octupole resonance in 40Ca and 208Pb, is in very good agreement with random-phase approximation calculations. The low-energy octupole resonance undergoes a pronounced change in structure in soft-vibrational and deformed nuclei. Theoretical calculations for the low-energy octupole resonance in 154Sm account qualitatively for the data
Structure and properties of copper deformed by severe plastic deformation methods
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M. Richert
2011-01-01
Full Text Available Purpose: The main object of this study is to establish the influence of severe plastic deformation on the microstructure evolution and properties of polycrystalline copper Cu99.99.Design/methodology/approach: Polycrystalline copper Cu99.99 was deformed by cyclic extrusion compression (CEC, equal channel angular pressing (ECAP and hydrostatic extrusion (HE. Additionally the combination of these methods were applying to the sample deformations. The microstructure and properties of samples after different kinds of severe mode of deformations (SPD were examined and compared as well as their properties. The microstructure was investigated by optical (MO and transmission electron microscopy (TEM. The microhardness was measured by PMT3 microhardness tester.Findings: It was found that increase of deformation diminishing the microstructure and leads to the increase of microhardness of samples.Practical implications: The results may be utilized for determination of a relation between microstructure and properties of the copper deformed in the severe plastic deformation process.Originality/value: The results contribute to evaluation properties of the polycrystalline copper deformed to very large strains exerting the typical range of deformations.
The octupoles take pole position
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.
Studies of electric dipole moments in the octupole collective regions of heavy Radiums and Bariums
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...
Some properties of deformed q-numbers
Scientific Electronic Library Online (English)
Thierry C. Petit, Lobão; Pedro G. S., Cardoso; Suani T. R., Pinho; Ernesto P., Borges.
2009-08-01
Full Text Available Nonextensive statistical mechanics has been a source of investigation in mathematical structures such as deformed algebraic structures. In this work, we present some consequences of q-operations on the construction of q-numbers for all numerical sets. Based on such a construction, we present a new p [...] roduct that distributes over the q-sum. Finally, we present different patterns of q-Pascal's triangles, based on q-sum, whose elements are q-numbers.
Deformation Properties of TiNi Shape Memory Alloy
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.
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.
q-deformed noncommutative cat states and their nonclassical properties
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.
Scaling properties of sea ice deformation during winter and summer
Hutchings, J. K.; Heil, P.; Roberts, A.
2009-12-01
We investigate sea ice deformation observed with ice drifting buoy arrays during two field campaigns. Ice Station POLarstern [ISPOL], deployed in the western Weddell Sea during November 2004 to January 2005, included a study of small-scale (sub-synoptic) variability in sea ice velocity and deformation using an array of 24 buoys. Upon deployment the ISPOL buoy array measured 70 km in both zonal and meridional extent, and consisted of sub-arrays that resolved sea ice deformation on scales from 10 to 70 km. The Sea Ice Experiment: Dynamic Nature of the Arctic (SEDNA) used two nested arrays of six buoys each as a backbone for the experiment, that were deployed in late March 2007. The two arrays were circular with diameter 140 km and 20 km. ISPOL and SEDNA provide insight into the scaling properties of sea ice deformation over scales of 10 to 200 km during early Astral summer and late Boreal winter. The ISPOL and SEDNA arrays were split into sets of sub-arrays with varying length scales. We find that variance of divergence decreases as the length scale increases. The mean divergence for each length scale set follows a log-linear scaling relationship with length scale. This is an independent verification of a previous result of Marsden, Stern, Lindsay and Weiss (2004). This scaling is indicative of a fractal process. Deformation occurs at linear features (cracks, leads and ridges) in the ice pack, that are distributed with scales that range from meter to hundreds of kilometers in length. The magnitude of deformation at these linear features varies by two orders of magnitude across scales. We demonstrate that the deformation at all these scales is important in the mass balance of sea ice. Which has important implications for the design of sea ice deformation monitoring systems.
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
The electrochemical properties of the cyclic deformed passive metals
International Nuclear Information System (INIS)
It has been investigated the influence of chloride environment on corrosion fatigue fracture of different classes stainless steels. The change of electrochemical properties of deformed corrosion resistance steels and alloys during the initial stage of corrosion fatigue fracture has been studied. It has been determined the influence of micro-deformation processes of surface at different tensions on the electrochemical activating of stainless steels. The critical values of electrochemical parameters of the deformed metal has been established, at which probability of corrosion fatigue fracture grows sharply. The features of character change polarization current of stainless steels at loadings even to corrosion fatigue limit has been shown. It served by basis for development of method speed-up determination of corrosion fatigue limit without destruction of specimens. It has been established possibility of decline corrosion currents of stainless steels as a result of deformation at tensions which do not cause destruction. It was revealed the reason of this effect: different acceleration by mechanical tensions of dissolution of alloys separate components, that results in enrichment of surface by a chrome and nickel. It is instrumental in the improvement of protective properties of passive tapes. The analysis of results of the conducted researches allowed to set that corrosion endurance of stainless steels is determined by intensity of their electrochemical activating at tensions of even to corrosive fatigue limit. (authors)
Microscopic description of octupole shape-phase transitions in light actinides and rare-earth nuclei
Nomura, K; Niksic, T; Lu, Bing-Nan
2014-01-01
A systematic analysis of low-lying quadrupole and octupole collective states is presented, based on the microscopic energy density functional framework. By mapping the deformation constrained self-consistent axially symmetric mean-field energy surfaces onto the equivalent Hamiltonian of the $sdf$ interacting boson model (IBM), that is, onto the energy expectation value in the boson condensate state, the Hamiltonian parameters are determined. The study is based on the global relativistic energy density functional DD-PC1. The resulting IBM Hamiltonian is used to calculate excitation spectra and transition rates for the positive- and negative-parity collective states in four isotopic chains characteristic for two regions of octupole deformation and collectivity: Th, Ra, Sm and Ba. Consistent with the empirical trend, the microscopic calculation based on the systematics of $\\beta_{2}$-$\\beta_{3}$ energy maps, the resulting low-lying negative-parity bands and transition rates show evidence of a shape transition be...
Strength and Deformation Properties of Tertiary Clay at Moesgaard Museum
DEFF Research Database (Denmark)
Kaufmann, Kristine Lee; Nielsen, Benjaminn Nordahl
2010-01-01
The tertiary clay at Moesgaard Museum near Aarhus in the eastern part of Jutland in Denmark is a highly plastic, glacially disturbed nappe of Viborg Clay. The clay is characterised as a swelling soil, which could lead to damaging of the building due to additional heave of the soil. To take this characteristic, as well as the strength and deformation properties, into account during the design phase, two consolidation tests and one triaxial test have been conducted. This paper evaluates the results of the laboratory tests leading to the preconsolidation stress, the deformation parameters consisting of the swelling pressure, the constrained modulus and the compression index, and the strength parameters comprising the undrained shear strength, the drained shear strength and the effective angle of internal friction
Radial damping by octupole for ZGS beam
International Nuclear Information System (INIS)
Landau damping by the octupolar tune spread is used to prevent the radial blowup of the beam during the acceleration cycle. The octupole field is produced by a set of pole face windings in the ring magnets. The strength of the octupole field, which is controlled by the Zero Gradient Synchrotron (ZGS) programmer, is set to give a tune profile of ?/sub x/ = 0.83 + 0.008 x a2, where a is the radial coordinate of the aperture in unit of cm. The radial damper feedback system, which has been operating for some years, has been replaced by this octupole, and the radial stability is remarkably improved by the new system
Fission fragment properties at scission with the Gogny force
Energy Technology Data Exchange (ETDEWEB)
Dubray, N.; Goutte, H.; Berger, J.F.; Delaroche, J.P. [CEA Bruyeres-le-Chatel, 91 (France)
2008-07-01
Two-dimensional Hartree-Fock-Bogoliubov (HFB) calculations have been performed from spherical shapes to large deformations with constraints on axial quadrupole and octupole deformations in U-238, Fm-256-260 and Th-226 actinides. Scission configurations have then been identified in this subspace of collective coordinates and many nuclear properties of the nascent fragments have been derived, such as deformation, deformation energy or prompt neutron multiplicity. The HFB states have then served as basis states for time-dependent collective calculations based on the Time-Dependent Generator Coordinate Method and the Gaussian Overlap Approximation to derive fission fragment yields. (authors)
Evolution of ground-state quadrupole and octupole stiffnesses in even-even barium isotopes
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).
Effect of deformation diagram on molybdenum structure and properties
International Nuclear Information System (INIS)
Effect of deformation diagram on a tendency to lamination and mechanical properties of disks made of molybdenum alloy is studied. Investigated samples were subjected to hot rolling or forging. X-ray structural analysis of texture is carried out along with estimation of the level of mechanical properties across item cross section. Sample mechanical bending tests were conducted. Sample microstructure is also studied. It is shown that rolled molybdenum has a tendency to lamination, but forged molybdenum is free of such a tendency. Forged sample ductility is practically equal in all directionse but rolled sample ductility in a surface layer is high and decreases with depth. A conclusion is drawn that forged sample grains in a setting surface are equiaxial, but distinct deformation texture is observed for rolled samples and their grains are elongated in the direction of rolling. A conclusion is made that a flow diagram of the process of disk fabrication by forging or stamping ppovides a necessary complex of physicomechanical properties of metal as compared to polling, and metal discharge coefficient decreases sharply in this case
Parametrization of the octupole degrees of freedom
Wexler, C
1999-01-01
A simple parametrization for the octupole collective variables is proposed and the symmetries of the wave functions are discussed in terms of the solutions corresponding to the vibrational limit. [PACS: 21.60Ev, 21.60.Fw, 21.10.Re
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.
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
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
Some Electronic Properties of Metals through q-Deformed Algebras
Tristant, Damien; Brito, Francisco A.
2013-01-01
We study the thermodynamics of metals by applying q-deformed algebras. We shall mainly focus our attention on q-deformed Sommerfeld parameter as a function of q-deformed electronic specific heat. The results revealed that q-deformation acts as a factor of disorder or impurity, modifying the characteristics of a crystalline structure and thereby controlling the number of electrons per unit volume.
International Nuclear Information System (INIS)
This chapter attempts to correlate the shock compression and quasistatic deformation of 6061-T6 aluminium. Examines recovered specimens which have been shock loaded, and compares results with both static and dynamic mechanical property measurements. Discusses experimental procedures (reshock and unloading experiments, shock recovery techniques, metallographic techniques and coldwork experiments); dynamic strength and wave-profile properties (strength and shear-stress states on the Hugoniot, steady-wave risetime and viscosity); quasistatic and shock metallography studies (metallography of quasistatically deformed material; metallography of shock deformed specimens; comparison of static and shock deformation; correlation of hardness and dynamic strength measurements); and thermal trapping calculations in shocked aluminium (heterogeneous deformation and adiabatic heating in shock-wave loading; energy and risetime relations under steadywave shock compression; heterogeneous temperature calculations in aluminium). Concludes that heterogeneous shear deformation appears to play a role in the dynamic deformation process
Effects of superplastic deformation on thermal and mechanical properties of 3Y-TZP ceramics (review)
International Nuclear Information System (INIS)
Our recent activities related to thermal and mechanical properties of superplastic ceramics, 3Y-TZP, are presented in this paper. These properties were obtained after the superplastic deformation process, because the effect of superplastic deformation on their properties is one of the important points from an application viewpoint of superplastic deformation such as forming and joining technologies. As for the thermal properties, specific heat was measured using the DSC method over a wide range of temperatures, from 473 K to 1273 K, with a nominal superplastic deformation strain of 70%. The crystal structure was characterised by measuring X-ray diffraction patterns, and microstructural observation was carried out using a SEM. As for the mechanical properties, dynamic hardness and Young's modulus were measured using the dynamic indentation technique with a maximum superplastic deformation of 150%. Microstructural observation was also carried out using a SEM after a thermal etching. (authors)
Double and triple octupole excitations in the A?150 region
International Nuclear Information System (INIS)
The results of recent experiments performed at L.N.L. on multiple octupole excitations in the N=84 isotones are reviewed. In particular, the results on B(E3) strengths in 146Sm are discussed and expectations for higher-order octupole excitations are compared with the present experimental situation
Octupole vibrations and ground state correlations
International Nuclear Information System (INIS)
The relationship between ground-state correlations and collectiveness is investigated for the case of low-lying nonrotational states in the rare earth nuclei. Both octupole and quadrupole modes of excitation are studied and the quasiparticle virtual populations associated with each of them are discussed. The relative importance of particle-particle and particle-hole interaction matrix elements is also analyzed in connection with the shape of the correlation patterns. The fundamental role of the Nilsson + BCS scheme is emphasized and the consistency of the quasiparticle random-phase approximation is established. (orig.)
Static and dynamic properties of deformable structures in random media
Mungan, Muhittin
1998-12-01
We investigate static and dynamic properties of deformable structures in random media, using numerical and analytical methods. The work comprising this thesis is divided into three parts. In the first part we examine metastable configurations of a two-dimensional system of interacting particles on a quenched random potential landscape and ask how the configurational pair correlation function is related to the particle interactions and the statistical properties of the potential landscape. Understanding this relation facilitates quantitative studies of magnetic flux line interactions in type II superconductors, using structural information available from Lorentz microscope or Bitter decoration images. Previous work supported the conjecture that the relationship between pair correlations and interactions in pinned flux line ensembles is analogous to the corresponding relationship in the theory of simple liquids. Here we aim at a more thorough understanding of this relation. We describe results of numerical simulations and present a theory for the low density behavior of the pair correlation function which agrees well with our simulations and captures features observed in experiments. The resulting description goes beyond the conjectured classical liquid type relation. In the second part of this thesis we analyze strains near threshold in one dimensional charge density wave models at zero temperature and strong pinning. We demonstrate that local strains diverge near the depinning threshold and characterize the scaling behavior of the phenomenon using finite-size scaling techniques. This divergence implies the breakdown of the elastic description and the necessity to consider plastic effects. Our results help quantify when the underlying elastic description breaks down and plastic effects have to be included. In the third part we study sliding charge density wave models in the presence of temperature with emphasis on strains as well as the sliding velocity. We observe numerically a suppression of strains near depinning threshold with increasing temperature. As temperature is further increased, a cross-over into a regime with increasing strains occurs. Using a high force expansion we are able to account qualitatively for the mechanism of strain suppression by temperature. We also capture quantitatively the average strain behavior in this limit.
Octupole focusing in transport and acceleration systems
International Nuclear Information System (INIS)
The radio-frequency quadrupole (RFQ) linac is capable of accelerating high-current, low-velocity ion beams. In accelerator systems comprising an RFQ and higher velocity accelerating structures, the current bottleneck still typically occurs within the RFQ. This limiting current is quite high in most cases, but linacs with even higher currents may be required in the future. We have begun a study of higher multipole systems to determine their capability for focusing and accelerating very high currents. We have chosen first to examine a radio-frequency octupole (RFO) transport system, and have developed a smooth-approximation analytical description that includes the conditions for input radial matching of a zero space-charge beam. Further, we have constructed a multiparticle beam-dynamics simulation program that accepts the low-current matched beam and gradually increases the beam current as it is transported. This results in a matched high-current beam, and the procedure can be used to determine the saturation-current limit of a periodic octupole system. As expected, at high currents the beam develops a hollow radial distribution that reduces the space-charge defocusing; initial results show that high currents can be transported. For acceleration, we have formulated the design parameters for a section of RFO linac, including the potential function, acceleration, and focusing efficiencies, and the geometry of the radially modulated pole tips
Octupole focusing in transport and accelerator systems
International Nuclear Information System (INIS)
The radio-frequency quadrupole (RFQ) linac is capable of accelerating high-current, low-velocity ion beams. In accelerator systems comprising an RFQ and higher velocity accelerating structures, the current bottleneck still typically occurs within the RFQ. This limiting current is quite high in most cases, but linacs with even higher currents may be required in the future. We have begun a study of higher multipole systems to determine their capability or focusing and accelerating very high currents. We have chosen first to examine a radio-frequency octupole (RFQ) transport system, and have developed a smooth-approximation analytical description that includes the conditions for input radial matching of a zero space-charge beam. Further, we have constructed a multiparticle beam-dynamics simulation program that accepts the low-current matched beam and gradually increases the beam current as it is transported. This results in a matched high-current beam, and the procedure can be used to determine the saturation-current limit of a periodic octupole system. As expected, at high currents the beam develops a hollow radial distribution that reduces the space-charge defocusing; initial results show that high currents can be transported. For acceleration, we have formulated the design parameters for a section of RFQ linac, including the potential function, acceleration, and focusing efficiencies, and the geometry of the radially modulated pole tips
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
Spectroscopy of quadrupole and octupole states in rare-earth nuclei from a Gogny force
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...
International Nuclear Information System (INIS)
A systematic investigation of the effect of high-temperature deformation by torsion under quasi-hydrostatic pressure on the microstructure, texture and superconducting properties of Bi2212 ceramics was carried out. Intercolony sliding was identified as the main mechanism of plastic deformation and basal texture formation. In all investigated deformation regimes the colony thickness did not change, only their length varied. The superconducting properties were analyzed as caused by the action of three main pinning centers: intracolonial lattice defects, low-angle colony boundaries and particles of secondary phases which appear during the decomposition of the Bi2212 phase near the melting point
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
Measuring the full transverse beam matrix using a single octupole
Ögren, J.; Ruber, R.; Ziemann, V.; Farabolini, W.
2015-07-01
We propose a method to fully determine the transverse beam matrix using a simple setup consisting of two steering magnets, an octupole field and a screen. This works in principle for any multipole field, i.e., sextupole, octupole magnet or a radio frequency structure with a multipole field. We have experimentally verified the method at the Compact Linear Collider Test Facility 3 at CERN using a Compact Linear Collider accelerating structure, which has an octupole component of the radio frequency fields. By observing the position shifts of the beam centroid together with changes in transverse beam size on a screen, we determined the full transverse beam matrix, with all correlations.
String field theory. Algebraic structure, deformation properties and superstrings
Energy Technology Data Exchange (ETDEWEB)
Muenster, Korbinian
2013-07-23
This thesis discusses several aspects of string field theory. The first issue is bosonic open-closed string field theory and its associated algebraic structure - the quantum open-closed homotopy algebra. We describe the quantum open-closed homotopy algebra in the framework of homotopy involutive Lie bialgebras, as a morphism from the loop homotopy Lie algebra of closed string to the involutive Lie bialgebra on the Hochschild complex of open strings. The formulation of the classical/quantum open-closed homotopy algebra in terms of a morphism from the closed string algebra to the open string Hochschild complex reveals deformation properties of closed strings on open string field theory. In particular, we show that inequivalent classical open string field theories are parametrized by closed string backgrounds up to gauge transformations. At the quantum level the correspondence is obstructed, but for other realizations such as the topological string, a non-trivial correspondence persists. Furthermore, we proof the decomposition theorem for the loop homotopy Lie algebra of closed string field theory, which implies uniqueness of closed string field theory on a fixed conformal background. Second, the construction of string field theory can be rephrased in terms of operads. In particular, we show that the formulation of string field theory splits into two parts: The first part is based solely on the moduli space of world sheets and ensures that the perturbative string amplitudes are recovered via Feynman rules. The second part requires a choice of background and determines the real string field theory vertices. Each of these parts can be described equivalently as a morphism between appropriate cyclic and modular operads, at the classical and quantum level respectively. The algebraic structure of string field theory is then encoded in the composition of these two morphisms. Finally, we outline the construction of type II superstring field theory. Specific features of the superstring are the appearance of Ramond punctures and the picture changing operators. The sewing in the Ramond sector requires an additional constraint on the state space of the world sheet conformal field theory, such that the associated symplectic structure is non-degenerate, at least on-shell. Moreover, we formulate an appropriate minimal area metric problem for type II world sheets, which can be utilized to sketch the construction of a consistent set of geometric vertices. The algebraic structure of type II superstring field theory is that of a N = 1 loop homotopy Lie algebra at the quantum level, and that of a N = 1 homotopy Lie algebra at the classical level.
High ? studies in the Wisconsin Toroidal OctupoleHigh ? studies in the Wisconsin Toroidal Octupole
International Nuclear Information System (INIS)
A wide range of MHD stable high ? plasmas is produced in the Wisconsin Levitated Octupole. At or near the single fluid regime we obtain, in the bad curvature region, ? = nk(T/sub e/ + T/sub i/)8?/B2 approx. = 8%, twice the theoretical single fluid ballooning instability limit of 4%. We also obtain stable plasmas at ? approx. = 35%, 9 times the theoretical limit, in a regime in which both finite ion gyroradius and gyroviscosity effects are importantA wide range of MHD stable high ? plasmas is produced in the Wisconsin Levitated Octupole. At or near the single fluid regime we obtain, in the bad curvature region, ? = nk(T/sub e/ + T/sub i/)8?/B2 approx. = 8%, twice the theoretical single fluid ballooning instability limit of 4%. We also obtain stable plasmas at ? approx. = 35%, 9 times the theoretical limit, in a regime in which both finite ion gyroradius and gyroviscosity effects are important
Dubray, N.; Goutte, H.; Delaroche, J.-P.
2007-01-01
The constrained Hartree-Fock-Bogoliubov method is used with the Gogny interaction D1S to calculate potential energy surfaces of fissioning nuclei ${}^{226}$Th and ${}^{256,258,260}$Fm up to very large deformations. The constraints employed are the mass quadrupole and octupole moments. In this subspace of collective coordinates, many scission configurations are identified ranging from symmetric to highly asymmetric fragmentations. Corresponding fragment properties at scission...
Dubray, N; Delaroche, J -P
2007-01-01
The constrained Hartree-Fock-Bogoliubov method is used with the Gogny interaction D1S to calculate potential energy surfaces of fissioning nuclei ${}^{226}$Th and ${}^{256,258,260}$Fm up to very large deformations. The constraints employed are the mass quadrupole and octupole moments. In this subspace of collective coordinates, many scission configurations are identified ranging from symmetric to highly asymmetric fragmentations. Corresponding fragment properties at scission are derived yielding fragment deformations, deformation energies, energy partitioning, neutron binding energies at scission, neutron multiplicities, charge polarization and total fragment kinetic energies.
Electronic Structure and Properties of Deformed Carbon Nanotubes
Yang, Liu; Arnold, Jim (Technical Monitor)
2001-01-01
A theoretical framework based on Huckel tight-binding model has been formulated to analyze the electronic structure of carbon nanotubes under uniform deformation. The model successfully quantifies the dispersion relation, density of states and bandgap change of nanotubes under uniform stretching, compression, torsion and bending. Our analysis shows that the shifting of the Fermi point away from the Brillouin zone vertices is the key reason for these changes. As a result of this shifting, the electronic structure of deformed carbon nanotubes varies dramatically depending on their chirality and deformation mode. Treating the Fermi point as a function of strain and tube chirality, the analytical solution preserves the concise form of undeformed carbon nanotubes. It predicts the shifting, merging and splitting of the Van Hove singularities in the density of states and the zigzag pattern of bandgap change under strains. Four orbital tight-binding simulations of carbon nanotubes under uniform stretching, compression, torsion and bending have been performed to verify the analytical solution. Extension to more complex systems are being performed to relate this analytical solution to the spectroscopic characterization, device performance and proposed quantum structures induced by the deformation. The limitations of this model will also be discussed.
Mechanical properties of hot deformed Inconel 718 and X750
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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.
Spectroscopy of quadrupole and octupole states in rare-earth nuclei from a Gogny force
Nomura, K.; Rodríguez-Guzmán, R.; Robledo, L. M.
2015-07-01
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 (?2?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 octupole collective structure fairly well and turns out to be consistent with GCM results obtained with the Gogny force.
Zhao, Jie; Zhao, En-Guang; Zhou, Shan-Gui
2012-01-01
The non-axial reflection-asymmetric $\\beta_{32}$ shape in some transfermium nuclei with N=150, namely $^{246}$Cm, $^{248}$Cf, $^{250}$Fm, and $^{252}$No are investigated with multidimensional constrained covariant density functional theories. By using the density-dependent point coupling covariant density functional theory with the parameter set DD-PC1 in the particle-hole channel, it is found that, for the ground states of $^{248}$Cf and $^{250}$Fm, the non-axial octupole deformation parameter $\\beta_{32} > 0.03$ and the energy gain due to the $\\beta_{32}$ distortion is larger than 300 keV. In $^{246}$Cm and $^{252}$No, shallow $\\beta_{32}$ minima are found. The occurrence of the non-axial octupole $\\beta_{32}$ correlations is mainly from a pair of neutron orbitals $[734]9/2$ ($\
Transient deformation properties of Zircaloy for LOCA simulation. Final report
International Nuclear Information System (INIS)
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
Mechanical properties of hot deformed Inconel 718 and X750
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...
International Nuclear Information System (INIS)
Low-alloyed tungsten alloys were obtained by melting with subsequent thermomechanical treatment under different conditions. The structure and substructure were studied by optical and electron microscopy methods. The width of X-ray diffraction lines was also determined to characterize microdistortions of the crystal lattice. The strength properties, plastic characteristics and ductile brittle transition temperature were determined in a 100-600 deg C temperature range under mechanical tensile tests. It is shown that in a high-deformed metal (degree of reduction approximately equal to 80% and more) the dislocation cell size governs some mechanical properties as well as the grain size determines there properties in a recrystallized state. It is shown that the structure parameters and mechanical properties of different tungsten alloys vary in dependence on t (deformation) in a similar way. The investigation also shows that the dispersed particle presence in a deformed tungsten alloy induces an indirect rather than direct strengthening
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Trumi? B.
2010-01-01
Full Text Available In order to form the necessary data base on platinum and platinum metals, certain tests were carried out on platinum samples of different purity of 99.5%, 99.9% and 99.99%. The degree of cold deformation, annealing temperature and chemical assays were tested as well as their impact on the mechanical properties of platinum. The Vickers hardness (HV values were determined with different deformation degree, starting from annealing temperatures for platinum of different purity and tensile strength (Rm, flow limit (Rp0,2 and elongation (A in the function of annealing temperatures and annealing time at a constant deformation degree.
Trumi? B.; Stankovi? D.; Ivanovi? A.
2010-01-01
In order to form the necessary data base on platinum and platinum metals, certain tests were carried out on platinum samples of different purity of 99.5%, 99.9% and 99.99%. The degree of cold deformation, annealing temperature and chemical assays were tested as well as their impact on the mechanical properties of platinum. The Vickers hardness (HV) values were determined with different deformation degree, starting from annealing temperatures for platinum of different purity and tensile streng...
DEFF Research Database (Denmark)
Huang, Xiaoxu
2009-01-01
The presence of a dislocation structure associated with low-angle dislocation boundaries and interior dislocations is a common and characteristic feature in nanostructured metals produced by plastic deformation, and plays an important role in determining both the strength and ductility of the nanostructured metals. The dislocation structure can be modified by post-process annealing and deformation which points to new ways of optimizing the mechanical properties. Such ways are demonstrated and discussed
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)
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.
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)
International Nuclear Information System (INIS)
The constrained Hartree-Fock-Bogoliubov method is used with the Gogny interaction D1S to calculate potential energy surfaces of fissioning nuclei 226Th and 256,258,260Fm up to very large deformations. The constraints employed are the mass quadrupole and octupole moments. In this subspace of collective coordinates, many scission configurations are identified ranging from symmetric to highly asymmetric fragmentations. Corresponding fragment properties at scission are derived yielding fragment deformations, deformation energies, energy partitioning, neutron binding energies at scission, neutron multiplicities, charge polarization, and total fragment kinetic energies
Estimating the mechanical properties of the brittle deformation zones at Olkiluoto
International Nuclear Information System (INIS)
In rock mechanics modelling to support repository design and safety assessment for the Olkiluoto site, it is necessary to obtain the relevant rock mechanics parameters, these being an essential pre-requisite for the modelling. The parameters include the rock stress state, the properties of the intact rock and the rock mass, and the properties of the brittle deformation zones which represent major discontinuities in the rock mass continuum. However, because of the size and irregularity of the brittle deformation zones, it is not easy to estimate their mechanical properties, i.e. their deformation and strength properties. Following Section 1 explaining the motivation for the work and the objective of the Report, in Sections 2 and 3, the types of fractures and brittle deformation zones that can be encountered are described with an indication of the mechanisms that lead to complex structures. The geology at Olkiluoto is then summarized in Section 4 within the context of this Report. The practical aspects of encountering the brittle deformation zones in outcrops, drillholes and excavations are described in Sections 5 and 6 with illustrative examples of drillhole core intersections in Section 7. The various theoretical, numerical and practical methods for estimating the mechanical properties of the brittle deformation zones are described in Section 8, together with a Table summarizing each method's advantages, disadvantages and utility in estimating the mechanical properties of the zones. We emphasise that the optimal approach to estimating the mechanical properties of the brittle deformation zones cannot be determined without a good knowledge, not only of each estimation method's capabilities and idiosyncrasies, but also of the structural geology background and the specific nature of the brittle deformation zones being characterized. Finally, in Section 9, a Table is presented outlining each method's applicability to the Olkiluoto site. A flowchart is included to indicate the proposed structure for a brittle deformation zone mechanical property estimation campaign, noting that the exact nature of future work will depend on the results of the ONKALO Prediction-Outcome studies and decisions on the rock mechanics work required to support the repository design. (orig.)
Tidal deformations of a spinning compact object
Pani, Paolo; Gualtieri, Leonardo; Maselli, Andrea; Ferrari, Valeria
2015-07-01
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 tidal Love numbers in general relativity, which are due to the difficulty in separating the tidal field from the linear response of the object in the solution, even in the static case. By extending the standard procedure to identify the linear response in the static case, we prove analytically that the Love numbers of a Kerr black hole remain zero to second order in the spin. As a by-product, we provide the explicit form for a slowly-rotating, tidally-deformed Kerr black hole to quadratic order in the spin, and discuss its geodesic and geometrical properties.
Determination of the deformation properties of Søvind Marl
DEFF Research Database (Denmark)
GrØnbech, Gitte; Nielsen, Benjaminn Nordahl
2010-01-01
A serie of tests were made to determine the preconsolidation stresses, ??pc, and the consolidation modulus, K, of Søvind Marl, a fissured plastic tertiary clay. The fissures causes a decrease in the stiffness of the Søvind Marl, which can be mistaken for the decrease that happens when the effective stresses in the soil, ??, passes ??pc. The effects of the fissures are assessed, and an estimate of the stress level at which they will compress are made. During the consolidation tests, the effective stress level is raised to more then 24,000 kPa to get a comprehensive description of the preconsolidation of the soil. It is important to know how a strongly preconsolidated soil will deform when reloaded. The deformation parameters of the strongly preconlidated Søvind Marl is determined by unloading/reloading testing. It is found that the stiffness of the Søvind Marl depends of the plasticity index, and one conclusive expression of the consolidation modulus of the Søvind Marl can therefor not be given.
Gadenne, Leslie; Raimbourg, Hugues; Champallier, Rémi; Yamamoto, Yuzuru
2014-12-01
better constrain the mechanical behavior of sediments accreted to accretionary prism, we conducted triaxial mechanical tests on natural samples from the Miura-Boso paleo-accretionary prism (Japan) in drained conditions with confining pressures up to 200 MPa as well as postexperiments P-wave velocity (Vp) measurements. During experiments, deformation is principally noncoaxial and accommodated by two successive modes of deformation, both associated with strain-hardening and velocity-strengthening behavior: (1) compaction-assisted shearing, distributed in a several mm-wide shear zone and (2) faulting, localized within a few tens of ?m-wide, dilatant fault zone. Deformation is also associated with (1) a decrease in Young's modulus all over the tests, (2) anomalously low Vp in the deformed samples compared to their porosity and (3) an increase in sensitivity of Vp to effective pressure. We interpret this evolution of the poroelastic properties of the material as reflecting the progressive breakage of intergrain cement and the formation of microcracks along with macroscopic deformation. When applied to natural conditions, these results suggest that the deformation style (localized versus distributed) of shallow (z cement breakage and microcracks formation, may lower Vp for effective pressure up to 40 MPa. As a consequence, the low Vp anomalies observed in Nankai accretionary prisms by seismic imaging between 2 and 4 km depth could reflect sediment deformation rather than porosity anomalies.
Effect of material property heterogeneity on biomechanical modeling of prostate under deformation
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.
Spectroscopy and octupole coupling of high-spin states in 213Rn
International Nuclear Information System (INIS)
Excited states of 213Rn, up to spins of ? 55/2 ? and an excitation energy of ? 6 MeV, have been studied using ?-ray and electron spectroscopy following the reactions 208Pb(9Be,4n) and 204Hg(13C,4n). Eight isomeric states were identified and g-factors for five of these measured by the TDPAD technique. Several of the isomeric states decay by enhanced E3 transitions. The level scheme and electromagnetic properties of the isomers are compared with the results of semi-empirical shell-model calculations including calculations which explicitly account for the particle-octupole vibration coupling
Self-similarity properties of nafionized and filtered water and deformed coherent states
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.
Red Blood Cell Deformation Under Shear Flow: The Effect of Changing Cell Properties
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.
Mechanical Properties of Copper Processed by Severe Plastic Deformation.
Czech Academy of Sciences Publication Activity Database
Kunz, Ludvík
Rijeka : InTech, 2012 - (Collini, L.), s. 93-126 ISBN 978-953-51-0160-4 R&D Projects: GA ?R GAP108/10/2001 Keywords : copper * ultrafinegrained structure * fatigue properties * localization of cyclic plasticity Subject RIV: JL - Materials Fatigue, Friction Mechanics
Octupole correlations in excited 0{sup +} states of the actinides
Energy Technology Data Exchange (ETDEWEB)
Spieker, Mark; Endres, Janis; Zilges, Andreas [Institute for Nuclear Physics, University of Cologne (Germany); Bucurescu, Dorel; Pascu, Sorin; Zamfir, Nicolae-Victor [Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest (Romania); Faestermann, Thomas [Physik Department, Technische Universitaet Muenchen, Munich (Germany); Hertenberger, Ralf; Wirth, Hans-Friedrich [Fakultaet fuer Physik, Ludwig-Maximilians-Universitaet Muenchen, Munich (Germany)
2014-07-01
New experimental data has once again shown the importance of the octupole degree of freedom in the actinides. To further study possible admixtures of double-octupole structures to the wave function of positive-parity states, a high-resolution (p,t) experiment on {sup 242}Pu has been recently performed at the Q3D magnetic spectrograph in Munich. Excited 0{sup +} states were populated in {sup 240}Pu up to an excitation energy of 3 MeV. The new data allowed for a stringent test of the predictions of the spdf interacting boson model. In order to find possible double-octupole 0{sup +} candidates in the actinides, the signature of close-lying first and second excited 0{sup +} states has been proposed. It is found that the observation of this signature coincides with an E1 ?-decay of the first excited 0{sup +} state, while this state is strongly populated in the (p,t) reaction.
Effects of deformation rates on mechanical properties of PP/SEBS blends
Balkan, O.; H. Demirer; E. Sabri Kayal?
2011-01-01
Purpose: The goal of this study is to examine effects of tensile deformation rates ( ) on tensile properties of polypropylene/poly(styrene-b-ethylene-co-butylene-b-styrene) copolymer (PP/SEBS) blends and to determine suitable for accurate and reliable evaluation of mechanical properties of the blends in accordance with the results of Izod impact tests.Design/methodology/approach: PP/SEBS blends containing ?e = 0, 2.5, 5 and 10 volume % of SEBS thermoplastic elastomer were compounded using ...
International Nuclear Information System (INIS)
Highlights: ? Resistance spot welding is successfully used for severely deformed steel sheet. ? Microstructures of FZ and HAZ are refined to lower sizes at higher pass number. ? Mechanical properties in FZ and HAZ are increased with increasing the pass number. ? Electrode dip and nugget diameter are increased with increasing the pass number. - Abstract: The welding of nanostructured low carbon steel sheets produced by severe plastic deformation (SPD) has been considered in the present paper. Constrained groove pressing (CGP) method is used for imposing the severe plastic deformation to the steel sheets as a large pre-strain. The SPDed sheets are joined using resistance spot welding (RSW) process. The results show that severe plastic deformation can effectively increase the electrical resistivity of steel sheets; therefore it can affect the microstructure and mechanical properties of spot welds. Microstructure and mechanical properties of fusion zone, heat affected zone (HAZ), recrystallized zone and base metal of SPDed sheets are investigated and the results are compared with those of as-received specimens. The results show that with increasing the large pre-strain in sheets, at constant welding parameters (welding current and time), the fusion zone size, electrode indentation and nugget diameter are increased. Thus, peak load and hardness in fusion zone and HAZ are increased with increasing the CGP pass number. Also, the microstructures of fusion zone and HAZ are refined to lower sizes for larger pre-strained specimens.
Mechanical properties of mammalian cells in suspension measured by electro-deformation
International Nuclear Information System (INIS)
We describe a planar, micro-fabricated device for generating fringing non-uniform electric fields. We used it to measure the mechanical properties of individual mammalian cells in suspension by deforming them in time-varying, non-uniform electric fields. Electrical stresses generated by the planar microelectrodes were used to trap and stretch cells, while cell deformation was observed using optical microscopy. Two distinct cell types were compared after fitting strain data with a three-parameter 'standard linear solid' model of visco-elasticity, and with a two-parameter power-law method. Chinese hamster ovary (CHO) cells were approximately twice as stiff as U937 human promonocytes, and CHO cells displayed an elastic behaviour with recovery of initial shape, while U937 strain data bore witness to plastic deformation. Our results demonstrate that electrical stresses generated by micro-fabricated electrodes permit mechanical characterization of distinct mammalian cell types.
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
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.
Deformation Properties of Forest Soils in Karelia Affected by "Freeze-Defrost" Cycles
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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.
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.
International Nuclear Information System (INIS)
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.
Effect of Nb content on deformation behavior and shape memory properties of Ti–Nb alloys
Energy Technology Data Exchange (ETDEWEB)
Tobe, H. [Division of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan); Kim, H.Y., E-mail: heeykim@ims.tsukuba.ac.jp [Division of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan); Inamura, T.; Hosoda, H. [Precision and Intelligence Laboratory, Tokyo Institute of Technology, Yokohama 226-8503 (Japan); Nam, T.H. [School of Materials Science and Engineering and ERI, Gyeongsang National University, 900 Gazwadong, Jinju, Gyeongnam 660-701 (Korea, Republic of); Miyazaki, S., E-mail: miyazaki@ims.tsukuba.ac.jp [Division of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan); School of Materials Science and Engineering and ERI, Gyeongsang National University, 900 Gazwadong, Jinju, Gyeongnam 660-701 (Korea, Republic of); Center of Excellence for Advanced Materials Research, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia)
2013-11-15
Highlights: ? Reorientation of martensite variants occurred by the deformation of the {1 1 1} type I and ?2 1 1? type II twins. ? Magnitude of twinning shear in Ti–20Nb is larger than that in Ti–23Nb. ? Ti–20Nb exhibited a higher stress for the reorientation of martensite variants when compared with Ti–23Nb. -- Abstract: Deformation behavior and shape memory properties of Ti–(20, 23) at.% Nb alloys in a single ?? martensite state were investigated. The Ti–20Nb alloy exhibited a higher stress for the reorientation of martensite variants when compared with the Ti–23Nb alloy. The recovery strain due to the shape memory effect in the Ti–20Nb alloy was smaller than that in the Ti–23Nb alloy. Transmission electron microscope (TEM) observation revealed that the reorientation of martensite variants occurred by the deformation of {1 1 1} type I and ?2 1 1? type II twins. The Nb content dependence of the deformation behavior and shape memory properties was discussed considering the magnitude of twinning shear of the twins.
Effect of Nb content on deformation behavior and shape memory properties of Ti–Nb alloys
International Nuclear Information System (INIS)
Highlights: ? Reorientation of martensite variants occurred by the deformation of the {1 1 1} type I and ?2 1 1? type II twins. ? Magnitude of twinning shear in Ti–20Nb is larger than that in Ti–23Nb. ? Ti–20Nb exhibited a higher stress for the reorientation of martensite variants when compared with Ti–23Nb. -- Abstract: Deformation behavior and shape memory properties of Ti–(20, 23) at.% Nb alloys in a single ?? martensite state were investigated. The Ti–20Nb alloy exhibited a higher stress for the reorientation of martensite variants when compared with the Ti–23Nb alloy. The recovery strain due to the shape memory effect in the Ti–20Nb alloy was smaller than that in the Ti–23Nb alloy. Transmission electron microscope (TEM) observation revealed that the reorientation of martensite variants occurred by the deformation of {1 1 1} type I and ?2 1 1? type II twins. The Nb content dependence of the deformation behavior and shape memory properties was discussed considering the magnitude of twinning shear of the twins
Effects of deformation rates on mechanical properties of PP/SEBS blends
Directory of Open Access Journals (Sweden)
O. Balkan
2011-07-01
Full Text Available Purpose: The goal of this study is to examine effects of tensile deformation rates ( on tensile properties of polypropylene/poly(styrene-b-ethylene-co-butylene-b-styrene copolymer (PP/SEBS blends and to determine suitable for accurate and reliable evaluation of mechanical properties of the blends in accordance with the results of Izod impact tests.Design/methodology/approach: PP/SEBS blends containing ?e = 0, 2.5, 5 and 10 volume % of SEBS thermoplastic elastomer were compounded using a twin-screw extruder, and then moulded with an injection moulding machine. Morphology of PP/SEBS blends were analysed by scanning electron microscopy (SEM. Mechanical properties of the blends were investigated tensile and Izod impact tests. Tensile deformation rates 1= 1.67 ms–1 and 2 = 16.67 ms–1 were used to determine ultimate tensile properties.Findings: Morphological analyses revealed that SEBS elastomer particles were well-dispersed throughout PP matrix in irregular forms with a narrow size distribution and evidenced a two-phase system formation. At low deformation rate ( 1, PP and PP/SEBS blends did not fail during tensile tests despite maximum tensile deformation, ?max = 600%; therefore, tensile toughness (UT, stress and strain values at break point (?b and ?b of the blends were not determined. However, at high deformation rate ( 2, all specimens tested in this study failed; a slight decrease in ?b of the blends with SEBS elastomer was associated with a significant increase in ?b and UT. Strain-rate-sensitivity of PP/SEBS blends was promoted with SEBS elastomer.Research limitations/implications: Mechanical properties determined through high-velocity tests are beyond the scope of this study.Practical implications: of tensile testing machines is readily adjustable, while ?max of tensile testing machines is limited. Consequently, in order to evaluate reliably mechanical properties of ductile materials like PP/SEBS blends, must be so high that ductile materials can fail during tensile tests.Originality/value: Tensile testing at high strain rate 2 was concluded to be more suitable for evaluation of mechanical properties of PP/SEBS blends than that of at low strain rate.
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Neutron irradiation studies on superplastic zirconia-based ceramics are now in progress as an innovative basic project using the High-temperature Engineering Test Reactor (HTTR) in Japan. The characteristics of the zirconia-based engineering components, made through the formation of superplastic, may be strongly affected by their response to transient or steady-state heat flow. Reliable thermophysical properties such as the coefficients of thermal expansion and thermal conductivity are, therefore, needed to estimate and predict the influence of a high-temperature environment. Accordingly, one of this project's targets is to study the thermophysical properties of superplastic zirconia-based ceramics. The first stage of the research addresses the effects of superplastic deformations on the thermophysical properties of a typical superplastic ceramic, 3 mol% yttria-stabilised tetragonal zirconia polycrystals (3Y-TZP), in its un-irradiated state. First, superplastic tensile deformations were conducted on 3Y-TZP specimens under different conditions in order to obtain specimens with different microstructural characteristics. Afterwards, the following actions were taken: - Specific heat measurements were conducted on the specimens at temperatures ranging from 473 K to 1273 K. - The thermal diffusivity was measured using a laser flash method. The thermal conductivity was then calculated from the measured thermal diffusivity, specific heat and density. - The linear thermal expaeat and density. - The linear thermal expansion was measured by a push-rod type dilatometer from 300 K to 1473 K. The coefficient of linear thermal expansion (CTE) was estimated from the thermal expansion data. The results obtained from the above measurements are discussed, as is the microstructural evolution caused by the superplastic deformations. It was found that the specific heat was almost independent of microstructural evolution, whereas the thermal diffusivity, thermal conductivity and thermal expansion were quite sensitive to deformation-induced cavities. The changes in the average grain size and grain aspect ratio had almost no effect on the thermophysical properties within the present experimental range. (author)
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.
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
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 (Earth's crust.
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
Designing electronic properties of two-dimensional crystals through optimization of deformations
International Nuclear Information System (INIS)
One of the enticing features common to most of the two-dimensional (2D) electronic systems that, in the wake of (and in parallel with) graphene, are currently at the forefront of materials science research is the ability to easily introduce a combination of planar deformations and bending in the system. Since the electronic properties are ultimately determined by the details of atomic orbital overlap, such mechanical manipulations translate into modified (or, at least, perturbed) electronic properties. Here, we present a general-purpose optimization framework for tailoring physical properties of 2D electronic systems by manipulating the state of local strain, allowing a one-step route from their design to experimental implementation. A definite example, chosen for its relevance in light of current experiments in graphene nanostructures, is the optimization of the experimental parameters that generate a prescribed spatial profile of pseudomagnetic fields (PMFs) in graphene. But the method is general enough to accommodate a multitude of possible experimental parameters and conditions whereby deformations can be imparted to the graphene lattice, and complies, by design, with graphene's elastic equilibrium and elastic compatibility constraints. As a result, it efficiently answers the inverse problem of determining the optimal values of a set of external or control parameters (such as substrate topography, sample shape, load distribution, etc) that result in a graphene deformation whose associated PMF profile best matches a prescribed target. The ability to address this inverse problem in an expedited way is one key step for practical implementations of the concept of 2D systems with electronic properties strain-engineered to order. The general-purpose nature of this calculation strategy means that it can be easily applied to the optimization of other relevant physical quantities which directly depend on the local strain field, not just in graphene but in other 2D electronic membranes. (paper)
An octupole coil configuration for the Tandem Mirror Experiment Upgrade
International Nuclear Information System (INIS)
The octupole plug concept offers the attractive possibility of reducing the length of the plug and transition sections in tandem mirror reactors. In the Tandem Mirror Experiment Upgrade (TMX-U), the authors are designing an octupole plug-transition that will replace our current quadrupole plug-transition. The reduction in length is made possible by the more nearly circular plasma cross section throughout the plug and transition sections. The principal physics of the design is the magnetohydrodynamic (MHD) stabilization of the core plasma in the plug by a hot electron ring in the mantle region surrounding the core. This paper elaborates on the design configuration of the magnets. In particular, the configuration provides for adequate neutral beam lines-of-sight, and access for 0.615 MW of electron-cyclotron resonant heating (ECRH) on each end
Octupole collectivity in the ground band of 148Nd
International Nuclear Information System (INIS)
E3 matrix elements have been determined for transitions between states up to I?=13- in 148Nd, providing direct evidence for strong octupole collectivity in a rotational band. These values, as well as the corresponding E1 and E2 matrix elements, were obtained from Coulomb excitation data using 58Ni and 92Mo ions, projectile excitation using a 208Pb target, and from recoil distance lifetime measurements. The results are consistent with collective model predictions for 148Nd assuming intrinsic quadrupole and octupole moments of Q20?400 e fm2 and Q30?1500 e fm3. The E3 strength coupling the negative-parity states to the ? band is found to be appreciable
Correction of chromatic and geometric aberrations using sextupoles and octupoles
International Nuclear Information System (INIS)
The procedure for applying some chromatic corrections to a final transport line, neglecting space charge, utilizing the method suggested by Brown is described. The possibility of including octupoles into a point-to-point triplet system, as outlined by Fenster is studied. Positive results were obtained in both cases: (i) using 2 + I correcting sections with two pairs of non-interlaced sextupoles increased the fraction of beam with ?P/P = 1% onto a 0.1 cm radius target by more than a factor of 1.75; (ii) six octupoles placed into a point-to-point triplet system increased the fraction of a full emittance ?P/P = 0% beam striking a 0.1 cm radius target by a factor of 2.5
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
Directory of Open Access Journals (Sweden)
Tomovi? Nataša S.
2015-01-01
Full Text Available Hydrogel particles are often used as a carrier for immobilization of enzymes, polyphenolic antioxidants, whole microbial, plant or mammalian cells. In many processes, mechanical properties of alginate particles are essential due to their exposure to mechanical forces in production process. Determination and improvement of hydrogels mechanical properties is very important in prevention of the undesirable side effects during the manufacturing process and product application. The aim of this study was to define the mechanical properties of single particles submerged in water and in dry conditions using the compression method between two flat surfaces. The results indicated that the formulation of alginate beads and water loss during compression have significant influence on their mechanical behavior and stiffness. Calcium-alginate particles were produced using an electrostatic droplet extrusion technique, with an initial sodium alginate concentration of 1.5%w/v and calcium chloride (2.0% w/v as gelling solution. The research findings were used to determine the influence of working conditions, sample deformation (10-50% and different compression speeds (1-50mm/min on mechanical strength of alginate beads. The Young’s modules and maximal forces for investigated deformation percentage of the alginate particles were determined from generated force-displacement and stress-strain curves during compression. [Projekat Ministarstva nauke Republike Srbije, br. III 46010 i br. ON 174004
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.
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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
Klein, Emilie; Fleitout, Luce; Vigny, Christophe
2015-04-01
The interseismic and postseismic deformations preceding and following the large subduction earthquake of Maule (Chile, Mw8.8, 2010) have been closely monitored with GPS from 70 km up to 2000 km away from the trench. Post-seismic deformations exhibit a behavior generally similar to that already observed after the Aceh and Tohoku-Oki earthquakes: vertical uplift is observed on the oceanward side of the volcanic arc. A moderate large scale subsidence is associated with sizeable horizontal deformation in the far-field (500-2000km from the trench). In addition, near-field data (70-200km from the trench) feature a rather complex deformation pattern. A 3D FE code (Zebulon Zset) is used to relate these deformations to the mechanical properties of the mantle and of the subduction interface. The mesh features a spherical shell-portion from the core-mantle boundary to the Earth's surface, extending over more than 60 degrees in latitude and longitude. The overridding and subducting plates are elastic, and the asthenosphere is viscoelastic. We test the presence and shape of two low viscosity areas in the mantle : a low viscosity wedge (LVW) above the subducting plate extending beneath the volcanic arc, and a narrow low viscosity channel (LVCh) along the lower part of the subduction interface, and potentially deeper. All the viscoelastic regions feature a Burgers rheology and we invert for their mechanical properties and geometrical characteristics. Our best fitting models present, (i) an asthenosphere extending down to 270km, with a 'long-term' viscosity of the order of 3.1018Pa.s; (ii) a LVCh along the plate interface extending from depths of 50 to 150 km with viscosities slightly below 1018 Pa.s; (iii) a LVW restricted to the base of the lithosphere below the volcanic arc, with viscosities of a few 1018 Pa.s. Increased horizontal velocities are due to relaxation in both the asthenosphere and the LVCh. A deep channel is necessary to produce enough uplift in the middle-field (200-500km from the trench). Some additional slip on the plate interface, at shallow depth, is also necessary to explain all the characteristics of the near-field displacements.
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.
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
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.
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
Structure and properties of deformed alloys of tungsten-rich corner of W-Mo-Re-Hf-C system
International Nuclear Information System (INIS)
Main regularities of structure formation and mechanical properties changing are established for deformation of vacuum-melted low alloys in W-Mo-Re-Hf-C system. It is shown that during hot deformation a fibrous structure is formed which provides a dec-- crease of ductile-brittle transition temperature. All the alloys investigated after a 95% reduction are ductile at room temperature. Hot deformation in the range 1450-1350 deg C with 92-93% re-- duction in area does not result in a visible increase of alloy ultimate strength
Deformed photon-added nonlinear coherent states and their non-classical properties
Energy Technology Data Exchange (ETDEWEB)
Safaeian, O; Tavassoly, M K, E-mail: mktavassoly@yazduni.ac.ir [Atomic and Molecular Group, Faculty of Physics, Yazd University, Yazd (Iran, Islamic Republic of)
2011-06-03
In this paper, we will try to present a general formalism for the construction of deformed photon-added nonlinear coherent states (DPANCSs) |{alpha}, f, m), which in a special case lead to the well-known photon-added coherent state (PACS) |{alpha}, m). Some algebraic structures of the introduced DPANCSs are studied and particularly the resolution of the identity, as the most important property of generalized coherent states, is investigated. Meanwhile, it will be demonstrated that the introduced states can also be classified in the f-deformed coherent states, with a special nonlinearity function. Next, we will show that these states can be produced through a simple theoretical scheme. A discussion on the DPANCSs with negative values of m, i.e. |{alpha}, f, -m), is then presented. Our approach has the potentiality to be used for the construction of a variety of new classes of DPANCSs, corresponding to any nonlinear oscillator with known nonlinearity function, as well as arbitrary solvable quantum system with known discrete, non-degenerate spectrum. Finally, after applying the formalism to a particular physical system known as the Poeschl-Teller (P-T) potential and the nonlinear coherent states corresponding to a specific nonlinearity function f(n)={radical}n, some of the non-classical properties, such as the Mandel parameter, second-order correlation function, in addition to first- and second-order squeezing of the corresponding states, will be investigated numerically.
International Nuclear Information System (INIS)
Cu–Ge alloys with different stacking fault energies (SFEs) were prepared by induction melting and processed by severe plastic deformation (SPD) using three different deformation techniques, including rolling at room temperature (RTR), rolling at the liquid nitrogen temperature (LNR), and Split Hopkinson Pressure Bar (SHPB) impact followed by room temperature rolling (HK+RTR). The effects of SFE, strain rate and deformation temperature on the microstructures and mechanical properties were systematically investigated by X-ray diffraction analyses and tensile tests. It was found that the dislocation density and twin density of all the Cu alloys after the SPD processing increased with decreasing SFE, increasing strain rate or reducing deformation temperature, which led to simultaneously enhanced strength and improved ductility due to effective grain refinement. The mechanical properties of the Cu alloys can be optimized to a combination of high strength and excellent ductility by lowering the SFE, the intrinsic property of metals, or manipulating the extrinsic deformation conditions, that is, increasing strain rate, and/or decreasing deformation temperature
Nuclear deformation study from fast neutron scattering
International Nuclear Information System (INIS)
Studies of elastic and inelastic scattering of fast neutrons from vibrational and rotational nuclei lead to determination of the quadrupole, hexadecapole and octupole deformation parameters of the target nuclei. The success of the analyses, which are based on phenomenological models, proves that precise information about the shape of nuclei can be obtained. These informations are compared to those deduced from other reactions mechanisms such as Coulomb excitation with protons, ?-particles or heavy ions
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.
Energy Technology Data Exchange (ETDEWEB)
Farbaniec, Lukasz; Dirras, Guy [Universite Paris 13, Sorbonne Paris Cite LSPM-CNRS, 99, Avenue J. B. Clement, 93430 Villetaneuse (France); Abdul-Latif, Akrum [Laboratoire d' Ingenierie des Systemes Mecaniques et des Materiaux 3, Rue Fernand Hainaut, 93407 St. Ouen Cedex (France); Gubicza, Jeno [Department of Materials Physics, Eoetvoes Lorand University Budapest, P.O. Box 32, H-1518 (Hungary)
2012-11-15
Bulk ultrafine-grained samples are processed by dynamic plastic deformation at an average strain rate of 3.3 x 10{sup 2} s{sup -1} from bulk coarse-grained nickel with purity higher than 98.4 wt.%. The obtained microstructure is investigated by electron backscattering diffraction, transmission electron microscopy and X-ray line profile analysis. After dynamic deformation the microstructure evolves into submicron-size lamellar and subgrain structures. Evaluation of average grain size shows a heterogeneous microstructure along both the diameter and the thickness of the sample. X-ray line profile analysis reveals high dislocation density of about 13 {+-} 2 x 10{sup 14} m{sup -2} in the impacted material. The mechanical properties are investigated by means of uniaxial quasi-static compression tests conducted at room temperature. The stress-strain behavior of the impacted Ni depends on the location in the impacted disk and on the orientation of the compression axis relative to the impact direction. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Greger, M.; V. Vodárek; L. Kander; L. ??žek
2009-01-01
Purpose: Maim aim of this paper is to describe the plastic deformation executed by ECAE of low carbon steel. The ECAE method lead to significant improvement of strength of investigated material.Design/methodology/approach: Experiments were planned and realised an the temperature ranging from room temperature up 280oC. After application of deformation the structure was investigated in dependence on accumulation of deformation and deformation temperature as well as abovementioned final properti...
Tensile properties of a nickel-base alloy subjected to surface severe plastic deformation
Energy Technology Data Exchange (ETDEWEB)
Tian, J.W. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN (United States); Dai, K. [Quality Engineering and Software Technology, East Hartford, CT 06108 (United States); Villegas, J.C. [Intel Corporation, Chandler, AZ (United States); Shaw, L. [Department of Chemical, Materials and Biomolecular Engineering, University of Connecticut, Storrs, CT (United States)], E-mail: leon.shaw@uconn.edu; Liaw, P.K. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN (United States); Klarstrom, D.L. [Haynes International, Inc., Kokomo, IN (United States); Ortiz, A.L. [Departamento de Ingenieria Mecanica, Energetica y de los Materiales, Universidad de Extremadura, 06071 Badajoz (Spain)
2008-10-15
A surface severe plastic deformation (S{sup 2}PD) method has been applied to bulk specimens of HASTELLOY C-2000 alloy, a nickel-base alloy. The mechanical properties of the processed C-2000 alloy were determined via tensile tests and Vickers hardness measurements, whereas the microstructure was characterized using scanning electron microscopy, transmission electron microscopy, and X-ray diffractometry. The improved tensile strength was related to the nanostructure at the surface region, the residual compressive stresses, and the work-hardened surface layer, all of which resulted from the S{sup 2}PD process. To understand the contributions of these three factors, finite element modeling was performed. It was found that the improved tensile strength could be interpreted based on the contributions of nano-grains, residual stresses, and work hardening.
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.
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.)
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.)
Properties of non-equilibrium grain boundaries in UFG nickel produced by severe plastic deformation
Energy Technology Data Exchange (ETDEWEB)
Reglitz, Gerrit; Divinski, Sergiy; Roesner, Harald; Wilde, Gerhard [Institute of Materials Physics, University of Muenster, Wilhelm-Klemm-Str. 10, 48149 Muenster (Germany)
2011-07-01
Ultra-fine grained (UFG) materials produced by severe plastic deformation (SPD) have become an important target of research due to their improved properties and the promise they hold with respect to novel applications. It has been suggested by several authors that so-called non-equilibrium grain boundaries in SPD processed materials are largely responsible for their properties. These non-equilibrium grain boundaries contain a high density of extrinsic (excess) dislocations and an increased excess free volume. The existence and the properties of non-equilibrium grain boundaries can be studied in great detail by grain boundary diffusion measurements, because such non-equilibrium grain boundaries should represent ultra-fast diffusion paths in comparison to conventional, relaxed high-angle grain boundaries in coarse grained materials. Grain boundary self-diffusion in UFG Ni prepared by Equal Channel Angular Pressing (ECAP) has been measured by applying the 63Ni radioisotope in combination with the parallel sectioning technique. The results indicate the existence of ultra-fast diffusion paths. The influence of the ECAP processing parameters will be presented. The origin of the ultra-fast diffusion pathways and their possible relation to non-equilibrium grain boundaries will be discussed.
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.
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.
Reinvestigation of high spin states and proposed octupole correlations in Ce147
Li, H. J.; Zhu, S. J.; Hamilton, J. H.; Wang, E. H.; Ramayya, A. V.; Chen, Y. J.; Hwang, J. K.; Ranger, J.; Liu, S. H.; Xiao, Z. G.; Huang, Y.; Zhang, Z.; Luo, Y. X.; Rasmussen, J. O.; Lee, I. Y.; Ter-Akopian, G. M.; Oganessian, Yu. Ts.; Ma, W. C.
2014-10-01
High spin states in neutron-rich Ce147 have been reinvestigated by measuring the triple- and fourfold ?-? coincidence data observed in the spontaneous fission of Cf252. The positive-parity band is expanded to spin (45/2) ? and the negative-parity side band is expanded to spin (39/2) with a new third band connected to it. An octupole band structure with s =+i was proposed. The systematic characteristics of the octupole correlations have been discussed. Reflection asymmetric shell model calculations for the octupole band structure of Ce147 are in good agreement with the experimental data.
M. Bender; Bennaceur, K.; Duguet, T; Heenen, P.-H.; Lesinski, T.; Meyer, J.
2009-01-01
We study systematically the impact of the time-even tensor terms of the Skyrme energy density functional, i.e. terms bilinear in the spin-current tensor density, on deformation properties of closed shell nuclei corresponding to 20, 28, 40, 50, 82, and 126 neutron or proton shell closures. We compare results obtained with three different families of Skyrme parameterizations whose tensor terms have been adjusted on properties of spherical nuclei: (i) TIJ interactions proposed ...
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
An extended deformation model of 24Mg
International Nuclear Information System (INIS)
A quadrupole- and octupole-deformed field is realized in the K sup(?) = 0+-, 2+, 3- rotational bands of 24Mg. The K sup(?) = 0+- bands make the inversion doublet with the lowest configuration. the K sup(?) = 2+ and 3- bands are built upon their respective single 1p-1h configurations. The deformed-shell character dominates in the low-lying states of 24Mg, particularly in the K sup(?) = 0+, 2+, 3- bands. The effects of the one-body and two-body spin-orbit forces are discussed. (author)
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 (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.
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
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.
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.
Shape coexistence and octupole vibrations in 74Se
International Nuclear Information System (INIS)
The results of a study of high spin states of 74Se using two reactions, 58Ni(19F,3p) and 48Ti(32S,?2p), are presented. The ground-state band is extended up to J?=(24+), and three other bands are also extended to higher spins than those known previously. Lifetimes of states in the ground-state band (J=6--16) and an odd-spin negative-parity band (J=9--13) measured by the Doppler-shift attenuation method are reported. A rotational band built on the 854-keV 0+ state is proposed, allowing the study of two coexisting K?=0+ bands to high spin. It is also concluded that energy and lifetime information support an octupole-band interpretation for the odd-spin negative-parity band
Shape coexistence and octupole vibrations in 74Se
Cottle, P. D.; Holcomb, J. W.; Johnson, T. D.; Stuckey, K. A.; Tabor, S. L.; Womble, P. C.; Buccino, S. G.; Durham, F. E.
1990-10-01
The results of a study of high spin states of 74Se using two reactions, 58Ni(19F,3p) and 48Ti(32S,?2p), are presented. The ground-state band is extended up to J?=(24+), and three other bands are also extended to higher spins than those known previously. Lifetimes of states in the ground-state band (J=6-16) and an odd-spin negative-parity band (J=9-13) measured by the Doppler-shift attenuation method are reported. A rotational band built on the 854-keV 0+ state is proposed, allowing the study of two coexisting K?=0+ bands to high spin. It is also concluded that energy and lifetime information support an octupole-band interpretation for the odd-spin negative-parity band.
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/
Mixed-symmetry octupole and hexadecapole excitations in the N=52 isotones
Hennig, A.; Spieker, M.; 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-scat...
Identication of New Levels and Proposed Octupole Correlations in Neutron-Rich 150,152Ce
Zhu, S. J.; Li, H. J.; Hamilton, J. H.; Ramayya, A. V.; Hwang, J. K.; Xiao, Z. G.; Sakhaee, M.; Guo, J. Y.; Chen, S. W.; Brewer, N. T.; Wang, E. H.; Liu, S. H.; Li, K.; Yeoh, E. Y.; Luo, Y. X.; Rasmussen, J. O.; Lee, I. Y.; Ter-Akopian, G.; Daniel, A.; Oganessian, Yu. Ts.; Ma, W. C.
2014-09-01
Level structures of the very neutron-rich 150,152Ce have been studied by measuring the prompt ?-rays in the spontaneous fission of 252Cf. The yrast bands have been confirmed and many levels and transitions are newly identified in both nuclei. The side-bands are tentatively assigned with negative parity and octupole band structures with s = +1 in 152,152Ce have been proposed. The systematic characteristics of the octupole correlations have been discussed.
Magnetic octupole order. The theoretical interpretation for resonant x-ray scattering
International Nuclear Information System (INIS)
The mysterious phase in CexLa1-xB6 is discussed with emphasis on the nature of the hidden order parameter. We explain the characteristic behaviors of ordered multipoles such as the electric quadrupole and the magnetic octupole, which become active in orbitally degenerate electron systems. We give the theoretical interpretation of the resonant X-ray measurement yielding that an antiferro magnetic octupole order is realized in this mysterious phase. (author)
Evaluation of the Mechanical Properties of AA 6063 Processed by Severe Plastic Deformation
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.
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.
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.
Changes in microstructure and physical properties of skutterudites after severe plastic deformation.
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
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.
Balachandran, S.; Seymour, N.; Mezyenski, R.; Barber, R.; Hartwig, K. T.
2014-01-01
The objective of this work is to demonstrate a seamless tube fabrication method for obtaining uniform fine grained microstructures by a novel shear deformation process for tubular metal products. The manufacture of fine grained RRR Nb superconducting radio frequency (SRF) cavities, and other tubular Nb products requires strict microstructure control with respect to grain size and texture for good formability. The major challenges in SRF cavity fabrication and performance stems from: a) the high cost of pure Nb, b) a poor and inconsistent microstructure in the starting material, and c) seam welding to manufacture multi-cell cavities. The approach presented by the authors indicates a possible strategy to obtain fine grain Nb tube by an innovative shear process. Grain size less than 30?m and tensile ductility greater than 40 percent in the orthogonal direction are achieved. The tensile properties correlate with the strongest texture component in the processed tube. Based on preliminary results, the proposed methodology maybe a viable and cost effective approach to fabricating a seamless Nb tube with good hydroformability.
International Nuclear Information System (INIS)
Adopted values for the excitation energy, Ex(31-), of the first 3- state of the even-even nuclei are tabulated. Values of the reduced electric-octupole transition probability, B(E3;O1+ ? 31-), from the ground state to this state, as determined from Coulomb excitation, lifetime measurements, inelastic electron scattering, deformation parameters ?3 obtained from angular distributions of inelastically scattered nucleons and light ions, and other miscellaneous procedures are listed in separate Tables. Adopted values for B(E3; O1+ ? 31-) are presented in Table VII, together with the E3 transition strengths, in Weisskopf units, and the product Ex(31-) x B(E3; O1+ ? 31--) expressed as a percentage of the energy-weighted E3 sum-rule strength. An evaluation is made of the reliability of B(E3; O1+ ? 31-) values deduced from deformation parameters ?3. The literature has been covered to March 1988
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A systematic analysis of microhardness variation is performed to study structural-mechanical heterogeneity in 14-layer titanium-steel (titanium VT1-0 + steel 08kp) composite specimens, produced by explosion welding with subsequent rolling at 700 deg C. The specimens studied are subjected to bending under a symmetrical three-point loading. Substantial changes in microhardness are revealed depending on the value and the sign of deformation. Tensile deformation of 15-17 % gives rise to partial softening of both titanium and steel layers. In a range of 1-2 % of compressive load deformation the steel layers are softened. At deformation above 4 % the steel is prone to hardening. In the titanium layers the microhardness monotonically increases with deformation
Interplay of inertia and deformability on rheological properties of a suspension of capsules
Krueger, Timm; Harting, Jens
2013-01-01
The interplay of inertia and deformability has a substantial impact on the transport of soft particles suspended in a fluid. However, to date a thorough understanding of these systems is still missing and only a limited number of experimental and theoretical studies is available. We combine the finite-element, immersed-boundary and lattice-Boltzmann methods to simulate three-dimensional suspensions of soft particles subjected to planar Poiseuille flow at finite Reynolds numbers. Our findings confirm that the particle deformation and inclination increase when inertia is present. We observe that the Segr\\'e-Silberberg effect is unstable with respect to the particle deformability. Depending on the deformability and strength of inertial effects, inward or outward lateral migration of the particles takes place. In particular, for increasing Reynolds numbers and strongly deformable particles, distinct flow focusing emerges which is accompanied by a non-monotonic behaviour of the apparent suspension viscosity and th...
Lalazissis, G. A.; Sharma, M. M.; Ring, P.
1995-01-01
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 descriptio...
Ground-state properties of axially deformed Sr isotopes in Skyrme-Hartree-Fock-Bogolyubov method
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Binding energies, the mean-square nuclear radii, neutron radii, quadrupole moments and deformation parameters to axially deformed Strontium isotopes were evaluated using Hartree-Fock-Bogolyubov method. Shape coexistence was also discussed. The results were compared with experimental data and some estimates obtained within some nuclear models. The calculations were performed for SIy4 set of Skyrme forces and for wide range of the neutron numbers of Sr isotopes
Effect of plastic deformation of a quenched maraging steel on its mechanical properties
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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
Local deformation and bulk properties in gamma-TiAl based alloys
Biery, Nicholas Eben
Gamma-TiAl alloys are potential replacements for conventional titanium and nickel-based alloys due to their high specific stiffness and good oxidation resistance at intermediate temperatures. One obstacle to implementation of these alloys is their relatively low ductility and the variation in that property. This work is an attempt to quantify ductility variability and understand the microstructural variables that affect it. It was found that a three-parameter Weibull analysis of tensile data using yield strength as the minimum failure strength isolates the variation in ductility from that in yield strength, and provides a useful way to quantify this variability. The properties of cast gamma-TiAl alloys are consistent with a volume-distributed flaw population, including exhibiting the expected reduction in strength with increased sample volume. Although other factors affect both strength and average ductility, the variability appears to be controlled by grain size alone; alloys with different microstructures but similar grain sizes had similar Weibull moduli. Fracture surface examinations indicated that the 'flaws' are intrinsic in nature; the fracture origins were generally not associated with pores, inclusions, or second phase particles. Instead, the typical origin was located in a small region that had undergone extensive plastic deformation. A technique, called AMaSD, was developed to accurately measure small-scale surface strains and identify the microstructural features associated with these areas of local high strain. These studies found that several factors affect the development of strain localization, including relative grain orientation, segregation, and phase distribution, but the relative importance of these factors are difficult to quantify. Finally, the cast structures of these materials were examined using texture measurements and statistical segregation studies, since texture and segregation had been identified as factors that could affect the distribution of high strain regions. Both alloy composition and cooling rate were found to affect the cast texture, but most alloys examined had textures consistent with solidification as single-phase hcp alpha growing along the c-axis. Slow cooling and high levels of aluminum promote alpha [1 0 - 1 0] growth instead, and it appears that high levels of niobium can promote [1 0 0] bcc beta-phase solidification.
Bright, A. M.; Shipton, Z. K.
2003-04-01
Deformation band faults in porous sandstone typically have a "core" of intense deformation associated with the localisation of strain onto discrete slip surfaces. In outcrop, the core is recognisable by its glassy appearance and its increased resistance to erosion with respect to the host rock. Samples of fault core have been collected from the San Rafael Swell, Utah, USA (Navajo Sandstone) and the Cheshire Basin, England (Sherwood Sandstone). Outcrop mapping in both localities reveals that the fault core thickness varies from sandstone (17-22%) and individual deformation bands (7-8%). However, microstructural observations suggest that fluids have moved through these structures during deformation. Cement phases are preferentially located along deformation band boundaries. Clay rims, which are common in the host rock, are absent in the fault core. Additionally preliminary fluid inclusion data show elevated temperatures in healed fault core microfractures. It is essential to characterise the architecture, composition and porosity/permeability of fault core to accurately predict fluid flow parallel and perpendicular to deformation band fault zones.
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.
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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
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Deformed microstructure and mechanical properties of AM60B magnesium alloy under hypervelocity impact at a speed of 4 km s-1 were studied through optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM) and indenter technique. The results show that the deformed microstructure below the crater can be classified as three zones, i.e. dynamic recrystallization zone, high density deformation twin zone and low density deformation twin zone. The refined and equiaxed recrystallized grains adjacent to the crater were formed, which should be attributed to the twining-induced dynamic recrystallization mechanism. The {101-bar 2}, {101-bar 1} deformation twins are confirmed through selected area electron diffraction (SAED) technique. The microhardness and yield strength in the deformed microstructure zone near the crater are much higher than that of the matrix, which should be attributed to strain hardening and grain refining.
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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
Fifth-order aberrations in magnetic quadrupole-octupole systems
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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
Deformation and energy absorption properties of powder-metallurgy produced Al foams
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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.
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
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We report measurements and modelling of magnetic effects due to plastic deformation in 2.2% Si steel, emphasizing new tensile deformation data. The modelling approach is to take the Ludwik law for the strain-hardening stress and use it to compute the dislocation density, which is then used in the computation of magnetic hysteresis. A nonlinear extrapolation is used across the discontinuous yield region to obtain the value of stress at the yield point that is used in fitting Ludwik's law to the mechanical data. The computed magnetic hysteresis exhibits sharp shearing of the loops at small deformation, in agreement with experimental behavior. Magnetic hysteresis loss is shown to follow a Ludwik-like dependence on the residual strain, but with a smaller Ludwik exponent than applies for the mechanical behavior
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In this paper, we introduce two new classes of nonlinear squeezed states that we name as f-deformed squeezed vacuum state |?, f?even and f-deformed squeezed first excited state |?, f?odd, which according to their production processes, essentially include only even and odd bases of Fock space, respectively. In the continuation, we introduce the superposition of these two distinct nonlinear squeezed states with a respective phase ?. Then, some of the criteria which imply the nonclassicality of the states, such as Mandel parameter, second-order correlation function, quadrature squeezing, amplitude-squared squeezing, Husimi and Wigner–Weyl quasi-distribution functions, are numerically examined. At last, by considering a well-known nonlinearity function associated with a nonlinear physical system, we present our results which outcome from the numerical calculations. It is shown that, the introduced f-deformed states can reveal high nonclassical features
Accretion onto Stars with Octupole Magnetic Fields: Matter Flow, Hot Spots and Phase Shifts
Long, Min; Lamb, Frederick K
2009-01-01
Recent measurements of the surface magnetic fields of classical T Tauri stars (CTTSs) and magnetic cataclysmic variables show that their magnetic fields have a complex structure. The magnetic field associated with the octupole moment may dominate the magnetic field associated with other moments in some stars, such as the CTTS V2129 Oph. Previously, we studied disc accretion onto stars with magnetic fields described by a superposition of aligned or misaligned dipole and quadrupole moments. In this paper, we present results of the first simulations of disc accretion onto stars with an \\textit {octupole} field. As examples, we consider stars with a superposition of octupole and dipole fields of different strengths and investigate matter flow around them, the shapes of hot spots on their surfaces, and the light curves produced by their rotation. We investigate two possible mechanisms for producing phase shifts in the light curves of stars with complex fields: (1) change of the star's intrinsic magnetic field and ...
Search for Two-Phonon Octupole Vibrational States and Multiplets in sr and zr Nuclei
Hwang, J. K.; Hamilton, J. H.; Ramayya, A. V.; Brewer, N. T.; Wang, E. H.; Luo, Y. X.; Rasmussen, J. O.; Zhu, S. J.
2014-09-01
Excited states in 88Sr were re-analyzed by assigning the new spins and parities according to the published DCO ratios (RDCO). Several new gamma transitions were identified in 92,93,94,96,97Sr and 96,97Zr from the spontaneous fission of 252Cf. Excited states in 88,92,93,94,96Sr and 95,96,97,98Zr were reanalyzed and reorganized to search for the new two-phonon octupole vibrational states and bands. Two-phonon octupole vibrational (POV) states are proposed for the spherical Sr and Zr nuclei near 88Sr and 96Zr. Multiple excited states (multiplets) with the same configuration in 88Sr were interpreted as the weak coupling of a 2+ one-phonon quadrupole or a 3- one-phonon octupole vibration to the excited 8+ state for 88Sr.
Czech Academy of Sciences Publication Activity Database
Antonova, N.; ?íha, Pavel; Ivanov, I.; Gluhcheva, Y.; Bonchev, G.
Munich : European Society for Clinical Hemorheology and Microcirculation, 2011. s. 13. [Conference of the European Society for Clinical Hemorheology and Microcirculation /16./, Annual Conference of the German Society for Clinical Microcirculation and Hemorheology /30./. 18.06.2011-21.06.2011, Munich] Institutional research plan: CEZ:AV0Z20600510 Keywords : red blood cells * electrical conductivity * deformability Subject RIV: BK - Fluid Dynamics
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
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.
International Nuclear Information System (INIS)
The methods are compared of electroslag welding and of arc welding with a view to their possible application in welding the Bohunice A-1 reactor pressure vessel. Considered are the thermal deformation effects of welding on the physical properties and the stress present in welded joints. For testing, plates were used having the dimensions of 1100x2300x200 mm and rings with 4820 mm outer diameter, 1800 mm height and 170 mm thickness made of steel CSN 413O30 modified with Ni, Al+Ti. The deformation effect of welding on the residual surface and triaxial stress, the specific stored energy, the initiation temperature of brittle crack and the critical size of the initiation defect corresponding to the thermal deformation effect of welding were determined. It was found that for electroslag welding, there is a low probability of crack formation in the joints, a low level of residual stress and a low level of specific stored energy in a relatively wide joint zone. For arc welding there is a considerable probability of defect formation in the vicinity of the sharp boundary of the joint, a high level of the triaxial state of stress in the tensile region, and a high level of specific stored energy concentrated in the narrow zone of weld joints. The recommended thermal process is given for welding pressure vessels made of the CSN 413030 steel modified with Ni, Al+Ti, and 150 to 200 mm in thickness. (J.P.)
Search for octupole correlations in neutron-rich 148Ce nucleus
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New transitions and levels in 148Ce have been observed in a ?-?-? coincidence study from the spontaneous fission of 252Cf with Gammasphere detector array. The ground band has been extended up to I?=22+, and side bands are extended with ?I=2 stretched transitions and ?I=1 crossing transitions. The observed level scheme is interpreted in terms of possible octupole correlations. Two sets of interwined positive- and negative- parity bands with the simplex quantum numbers s=±1 are suggested. The results of B(E1)/B(E2) branching ratios indicate that the octupole correlations in 148Ce are strong
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.
Grydin, O.; Stolbchenko, M.; Nürnberger, F.; Schaper, M.
2014-03-01
Thin strips of medium- and high-strength age-hardening aluminium alloys are widely used in the automotive industry. Reducing their production costs caused by high energy consumption is an actual challenge. The implementation of the twin-roll casting technology is promising. However, mechanical properties of directly cast high-alloyed thin aluminium strips are oftentimes inadequate to standard specifications. In this work, the influence of a hot deformation following a twin-roll cast strip process on the mechanical properties and microstructure is investigated. For this study strips of age-hardening aluminium alloy EN AW-6082—manufactured at a laboratory scaled twin-roll caster—were single-pass rolled at temperatures of 420 °C and true strains of up to 0.5. The mechanical properties of the as-cast and by different strains hot deformed material in the soft-annealed and age-hardened states were characterized by tensile tests. The results reveal that the twin-roll cast material features the necessary strength properties, though it does not meet the standard requirements for ductility. Furthermore, the required minimum strain during hot rolling that is necessary to ascertain the standard specifications has been determined. Based on micrographs, the uniformity of the mechanical properties and of the microstructure as a result of recrystallization due to hot metal forming and heat treatment were determined. A fine-grain microstructure and satisfactory material ductility after prior rolling with a true strain above 0.41 for the age-hardened state T6 and above 0.1 for the soft-annealed state O have been established.
Chaussard, E.; Burgmann, R.; Shirzaei, M.; Fielding, E. J.; Baker, B.
2014-12-01
Space geodesy has demonstrated its potential in detecting ground deformation associated with exploitation of aquifers. However, because geodetic data remain rarely integrated with hydrologic data, ground deformation observations are not typically used for water management purposes. Here, we characterize ground deformation of the Santa Clara Valley in the southern San Franciso Bay Area, an aquifer undergoing water extraction and recharge with over 50 multi-decadal monitoring wells. We perform Interferometric Synthetic Aperture Radar (InSAR) time-series analysis of ERS, Envisat, and ALOS SAR data to resolve the 1992-2011 ground deformation. Using T-mode Principal Component Analysis we isolate temporally and spatially variable deformation signals embedded in multi-decadal InSAR time series. The longer-term signal reveals uplift at 0.4 cm/yr between 1992-2000 and seasonal elastic deformation with amplitude of up to 3 cm, in phase with head fluctuations, is observed over the confined aquifer sharply partitioned by the Silver Creek Fault (SCF). We integrate the deformation with hydraulic head data to characterize the aquifer-system properties at the scale of the basin, and show that after calibration we can accurately predict hydraulic head levels from deformation alone. Finally, by modeling the deformation partitioning across the SCF we constrain the time of the fault's last tectonic activity, hydraulic conductivity, and material composition. The SCF cuts the shallow confining clays and was last active since ~140 ka, it has a horizontal hydraulic conductivity several orders of magnitude lower than the surrounding aquifer system, and it is likely composed of clays, making it an effective barrier to across-fault fluid flow. Our results demonstrate that space-derived ground deformation, when combined with hydrological data, enables characterization of basin-wide aquifer-system and fault properties and could help characterize hydraulic heads in areas with sparse temporal well monitoring.
Tidal deformations of a spinning compact object
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...
International Nuclear Information System (INIS)
The time-dependent phenomena which can affect the strength and deformation properties of hard crystal line rock are clarified. Suitable measuring methods for field conditions are also summarized. The significance of time is evaluated around a shaft in a high level nuclear waste repository. According to the investigation it is generally held that creep and cyclic fatigue are the most important phenomena. They arise from subcritical crack growth which is most affected by stress intensity, chemical environment, temperature, and microstructure. There are many theoretical models, which can be used to analyse creep and cyclic fatigue, but they are defective in describing the triaxial stress condition and strength criteria. Additionally, the required parameters are often too difficult to determine with adequate accuracy. The joint creep rate depends on the affecting stress regime, on the water conditions, and on the properties of filling material. The acoustic emission method is suited to observe long-term microcrack development in field conditions. The computer program developed by Atomic Energy of Canada Limited (AECL) is used to evaluate the time-dependent de-formation around a main shaft. According to the model the enlargement of the shaft radius by 30 cm takes millions of years. The possible reduction of shaft radius by 3 mm will happen during 200 years. The model is very sensitive to changes in stress state, in the uniaxial compressive strength, and in the stress corrosion index
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.
Barmouz, Mohsen; Besharati Givi, Mohammad Kazem; Jafari, Jalal
2014-01-01
In this work, the tensile behavior of pure copper including ultimate tensile stress, yield stress, and elongation in the specimens friction stir processed under different processing parameters and pass adding was investigated in detail. The effect of strain hardening, grain refinement, and heat input on the tensile properties of these specimens was explained as well. It was observed that, regarding the aforementioned factors, the processing parameters and pass number could have considerable effects on the tensile deformation properties of the pure copper such as 300 and 47% enhancements in elongation and ultimate strength, respectively. It was demonstrated that higher passes resulted in the development of ultrafine grains (up to 700-800 nm) in the specimens. The fracture surface morphology was also used to further support the elongation results.
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)
International Nuclear Information System (INIS)
In this report, the rock mechanics parameters of fractures and brittle deformation zones have been estimated in the vicinity of the ONKALO area at the Olkiluoto site, western Finland. This report is an extension of the previously published report: Geometrical and Mechanical properties if the fractures and brittle deformation zones based on ONKALO tunnel mapping, 0-2400 m tunnel chainage (Kuula 2010). In this updated report, mapping data are from 2400-4390 m tunnel chainage. Defined rock mechanics parameters of the fractures are associated with the rock engineering classification quality index, Q', which incorporates the RQD, Jn, Jr and Ja values. The friction angle of the fracture surfaces is estimated from the Jr and Ja numbers. There are no new data from laboratory joint shear and normal tests. The fracture wall compressive strength (JCS) data are available from the chainage range 1280-2400 m. Estimation of the mechanics properties of the 24 brittle deformation zones (BDZ) is based on the mapped Q' value, which is transformed to the GSI value in order to estimate strength and deformability properties. A component of the mapped Q' values is from the ONKALO and another component is from the drill cores. In this study, 24 BDZs have been parameterized. The location and size of the brittle deformation are based on the latest interpretation. New data for intact rock strength of the brittle deformation zones are not available. (orig.)
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.
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.)
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
Octupole coil configuration for the Tandem Mirror Experiment Upgrade (TMX-U)
International Nuclear Information System (INIS)
The octupole plug concept offers the attractive possibility of reducing the length of the plug and transition sections in tandem mirror reactors. In the Tandem Mirror Experiment Upgrade (TMX-U), we are designing an octupole plug-transition that will replace our current quadrupole plug-transition. The reduction in length is made possible by the more nearly circular plasma cross section throughout the plug and transition sections. The principal physics of the design is the magnetohydrodynamic (MHD) stabilization of the core plasma in the plug by a hot electron ring in the mantle region surrounding the core. This hot electron mantle is MHD stable because of the good curvature field lines provided by the octupole. The positive radial pressure gradient in the hot electron mantle in turn stabilizes the core's plasma. Each octupole set consists of six coils replacing the transition and plug sets in the existing TMX-U experiment. The central cell coils will remain unchanged. Five of the coils for each of the new sets will be fabricated, while one, the 6-T mirror coil, will be reused from TMX-U. This paper will elaborate on the design configuration of the magnets. In particular, the configuration provides for adequate neutral beam lines-of-sight, and access for 0.615 MW of electron-cyclotron resonant heating (ECRH) on each end
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
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
Surface properties of elastically deformed copper electrode in alkali metal chloride melts
Stepanov, V. P.; Sitnikov, L. V.
2014-02-01
The estans of a copper polycrystalline electrode in the NaCl, KCl, and CsCl melts and the NaCl-KCl and NaCl-CsCl eutectics is measured at various temperatures. The zero-charge potential of the elastically deformed electrode in these systems is determined. A mechanism is proposed for the interaction between salt-phase anions and the copper surface. It consists in the formation of a covalent bond between the atoms of a positively charged copper surface and the salt-phase anions with partial charge transfer to the metal.
Energy Technology Data Exchange (ETDEWEB)
Abbasi-Chianeh, V., E-mail: vahid61abbasi@gmail.com [Faculty of Mechanics Engineering, Urmia University of Technology, Urmia (Iran, Islamic Republic of); Research Center for Advanced Materials and Mineral Processing, Faculty of Materials Engineering, Sahand University of Technology, Tabriz (Iran, Islamic Republic of); Khalil-Allafi, J.; Kazemi-choobi, K. [Research Center for Advanced Materials and Mineral Processing, Faculty of Materials Engineering, Sahand University of Technology, Tabriz (Iran, Islamic Republic of)
2013-06-25
Highlights: ? Precipitation of Ni{sub 4}Ti{sub 3} during aging at 450 °C is hindered after severe cold work. ? Nanostructure formation improves the superelastic behavior of Ni-rich NiTi. ? Deformations less than 0.4 result in work hardening and reduce plateau strain. ? Deformations more than 0.4 yield in high stress and strain values of upper plateau. -- Abstract: Superelastic properties of Ni{sub 50.9}Ti shape memory wires were studied after cold drawing and post-deformation annealing at 450 °C. Characteristic transformation temperatures were determined using differential scanning calorimetry. Microstructural investigations were performed using optical and transmission electron microscopy. Results indicate that deformations more than 0.4 of true strain yield in high stress and high strain values of upper plateau. On the other hand, deformations less than 0.4 result in work hardening and reduce plateau strain. Post-deformation heat treatment at 450 °C leads to precipitation of Ni{sub 4}Ti{sub 3} particles and development of recovered microstructure in slightly cold drawn wires. Post-deformation annealing of wires with cold work value of 0.6 in true strain develop nanocrystalline microstructure and hindered the formation of Ni{sub 4}Ti{sub 3} precipitates. Precipitation of Ni{sub 4}Ti{sub 3} particles improves the superelastic properties of not cold drawn wires. However, in comparison with annealed and aged wires, severely deformed wires attain better superelastic properties after annealing at 450 °C without any Ni{sub 4}Ti{sub 3} precipitates.
Note on a search for the two-octupole phonon 2 + state in 208 Pb with resonant photon scattering
Enders, J.; von Brentano, P.; Eberth, J.; Fitzler, A.; Fransen, C.; Herzberg, R.-D.; Kaiser, H.; Käubler, L.; von Neuman-Cosel, P.; Pietralla, N.; Ponomarev, V. Yu.; Richter, A.; Schnare, H.; Schwengner, R.; Skoda, S.; Thomas, H. G.; Tiesler, H.; Weisshaar, D.; Wiedenhöver, I.
2000-07-01
Results of a 208 Pb (?,?') experiment are presented aiming at an identification of the 2 + member of the long-sought two-octupole phonon multiplet. Four E2 excitations have been observed below 6.5 MeV excitation energy, two of them for the first time. However, in contrast to new results of calculations within the quasiparticle-phonon nuclear model (QPM), no obvious candidate for the two-octupole phonon vibration could be found in the present study. We discuss the J ?=2 + states detected in this as well as previous experiments with respect to their possible two-octupole phonon structure.
Thermal Stability and Properties of Deformation-Processed Cu-Fe In Situ Composites
Liu, Keming; Jiang, Zhengyi; Zhao, Jingwei; Zou, Jin; Lu, Lei; Lu, Deping
2015-05-01
This paper investigated the thermal stability, tensile strength, and conductivity of deformation-processed Cu-14Fe in situ composites produced by thermo-mechanical processing. The thermal stability was analyzed using scanning electronic microscope and transmission electron microscope. The tensile strength and conductivity were evaluated using tensile-testing machine and micro-ohmmeter, respectively. The Fe fibers in the deformation-processed Cu-14Fe in situ composites undergo edge recession, longitudinal splitting, cylinderization, break-up, and spheroidization during the heat treatment. The Cu matrix experiences recovery, recrystallization, and precipitation phase transition. The tensile strength and conductivity first increase with increasing temperature of heat treatment, reach peak values at different temperatures, and then decrease at higher temperatures. The value of parameter Z of the in situ composite reaches the peak of 2.86 × 107 MPa2 pct IACS after isothermal heat treatment at 798 K (525 °C) for 1 hour. The obtained tensile strength and conductivity of the in situ composites are 907 MPa and 54.3 pct IACS; 868 MPa and 55.2 pct IACS; 810 MPa and 55.8 pct IACS; or 745 MPa and 57.4 pct IACS, at ? = 7.8 after isochronal heat treatment for 1 hour.
Directory of Open Access Journals (Sweden)
M. Greger
2009-05-01
Full Text Available Purpose: Maim aim of this paper is to describe the plastic deformation executed by ECAE of low carbon steel. The ECAE method lead to significant improvement of strength of investigated material.Design/methodology/approach: Experiments were planned and realised an the temperature ranging from room temperature up 280oC. After application of deformation the structure was investigated in dependence on accumulation of deformation and deformation temperature as well as abovementioned final properties.Findings: Accumulated deformation varied from the value 2 to 8. Investigation of structure by electron microscopy was made with use microscope JEOL JEM 2100. Mechanical properties were investigated by tensile test. Statistic evaluation of angular disorientation and of size of grains/sub-grains was also made with use of electron diffraction (EBSD in combination with scanning electron microscope FEG SEM Philips.Practical implications: The technology ECAE was applied on low carbon steel. It was verification of ECAE application possibility on steel P2-04BCH importantly for following applying on similar kinds of steel, because ECAE deformation influence.Originality/value: The results from his work shall be useful in determining conditions for fabrication of nanocrystalline or sub-microcrystalline steel by the ECAE technology.
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 predomina long-term use. This seems to be predominantly important in benign bronchial collapse
Lee, D. M.; Lim, C. H.; Cho, D. C.; Lee, Y. S.; Lee, C. H.
2006-02-01
We studied the effects of deformation and annealing of n-type 90Bi2Te3-5Sb2Te3-5Sb2Se3 thermoelectric compound. Hot-extrusion was conducted to prepare the deformed compound and then this compound was annealed at 400°C for 1-24 hr. When the undoped cast-ingot was extruded, the compound was changed from p-type to n-type due to the electrons generated during the extrusion process. For the compound extruded with SbI3-doped powders, the thermoelectric properties were also varied for the extrusion process. After annealing at 400°C more than 9 hr, the powder-extruded compound was recrystallized. This caused a decrease in carrier concentration and crystallographic anisotropy. In case of the compound extruded at the ratio of 10:1, the Seebeck coefficient ? and the electrical resistivity ? increased due to recrystallization. However, thermal conductivity ? of the compound decreased. This resulted in an increase in the figure-of-merit from 1.23 × 10-3 to 1.63 × 10-3 K-1.
Stepanov, G. V.; Chertovich, A. V.; Kramarenko, E. Yu.
2012-10-01
Viscoelastic and deformational behavior of soft magnetic elastomers with hard magnetic fillers under the influence of a magnetic field is studied by different experimental techniques. The magnetic elastomers used in this work were synthesized on the basis of silicone rubber filled with FeNdB particles and were magnetized in a field of 3 and 15 kOe. We have shown that due to high residual magnetization the materials demonstrate well pronounced non-elastic behavior already in the absence of any external magnetic field. In particular, in contrast to magnetic elastomers based on soft magnetic fillers their elastic modulus is strain-dependent. Under the influence of external magnetic field the storage and loss moduli of magnetic elastomers with hard magnetic filler can both increase and decrease tremendously.
International Nuclear Information System (INIS)
Viscoelastic and deformational behavior of soft magnetic elastomers with hard magnetic fillers under the influence of a magnetic field is studied by different experimental techniques. The magnetic elastomers used in this work were synthesized on the basis of silicone rubber filled with FeNdB particles and were magnetized in a field of 3 and 15 kOe. We have shown that due to high residual magnetization the materials demonstrate well pronounced non-elastic behavior already in the absence of any external magnetic field. In particular, in contrast to magnetic elastomers based on soft magnetic fillers their elastic modulus is strain-dependent. Under the influence of external magnetic field the storage and loss moduli of magnetic elastomers with hard magnetic filler can both increase and decrease tremendously.
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
International Nuclear Information System (INIS)
The 500 keV Xe2+ irradiation-induced anisotropic deformation of ordered colloidal silica nanoparticulate masks is followed using 2 MeV 4He+ Rutherford Backscattering Spectrometry (RBS) with different measurement geometries and the improved data analysis capabilities of the RBS-MAST spectrum simulation code. The three-dimensional (3D) geometrical transformation from spherical to oblate ellipsoidal and polygonal shape and the decrease of the mask's hole size is described. The masking properties of the silica monolayer and the depth distribution of Xe in the underlying Si substrate vs. the irradiated Xe2+ fluence are discussed. Field Emission Scanning Electron Microscopy (FESEM) is applied as complementary characterization tool. Our results give contribution to clarify the impact of ion-nanoparticle interactions on the potentials and limits of nanosphere lithography. We also show the capability of the conventional RBS technique to characterize laterally ordered submicron-sized three-dimensional structures.
International Nuclear Information System (INIS)
Highlights: ? Mechanical properties and microstructural evolution of cryorolled + warm rolled (WR) Al 5083 alloy were investigated. ? WR samples showed a significant improvement in tensile strength and ductility (6.8%) than CR samples. ? WR sample is thermally stable up to 250 °C. ? YS and UTS of WR sample annealed at 250 °C are 270 MPa and 330 MPa, respectively, and elongation to failure is 13%. - Abstract: Aluminum–Magnesium (Al 5083) alloy was subjected to cryorolling (CR) and cryorolling followed by warm rolling (WR) in order to investigate the changes in mechanical behavior and microstructure evolution in the present work. Al alloy specimens were first cryorolled up to 50% thickness reduction followed with warm rolling at 100 °C, 145 °C, 175 °C and 200 °C till to achieve total 90% thickness reduction. The final microstructure of all conditions were analyzed and compared through transmission electron microscopy (TEM), Electron back scattered diffraction (EBSD), and X-ray diffraction (XRD) techniques to investigate the effect of WR deformation temperatures on mechanical properties. The mechanical behavior of the processed samples were evaluated through hardness and tensile tests performed at room temperature. An increase in yield strength (522 MPa), ultimate tensile strength (539 MPa) and ductility (6.8%) was observed in WR specimens at 175 °C, hardness also increases to (146 HV) as compared to CR samples. These samples were annealed in temperature range from 150 °C to 300 °C to investigate their thermal stability. The CR samples exhibited severely deformed structure with high dislocation density network while cryorolled followed by warm rolled (WR) samples has shown formation of ultrafine grains associated with dynamic recovery. At elevated temperature of 200 °C, WR samples showed decrease in strength accompanied with increase in elongation due to dominant dynamic recovery effect led to reduction in dislocation density
Role of deformation on giant resonances within the QRPA approach and the Gogny force
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.
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.
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 anical properties depend on both, grain size and area fraction of HAGBs.
Czech Academy of Sciences Publication Activity Database
Antonova, N.; ?íha, Pavel; Ivanov, I.
2009-01-01
Ro?. 42, ?. 3 (2009), s. 211-212. ISSN 1386-0291. [Conference of the European Society for Clinical Hemorheology and Microcirculation /15./. 28.06.2009-01.07.2009, Pontresina] R&D Projects: GA AV ?R IAA200600803 Institutional research plan: CEZ:AV0Z20600510 Keywords : RBC electrical properties Subject RIV: BK - Fluid Dynamics
International Nuclear Information System (INIS)
Influence of deformation at 25% under uniform compression at pressure of 22 and 16.5 kbar at 77 K and 12 and 8 kbar at 300 K by using quasi hydroextrusion with counter pressure (QHEC) and without counter pressure (QHE) on physical-mechanical properties of titanium VT1-0 in the range of 77...800 K was investigated. It was shown, that two-stage character of dependence mechanical properties versus temperature in initial state (temperature-dependent in the range of 77...600 K and athermal in the range of 600...800 K) after deformation QHE and QHEP changed to one-stage and temperature-dependent character in the entire temperature range. It was shown that deformation under uniform pressure result in increase of strength in the range of 77...800 K and decrease the stacking fault energy of titanium. That is an addition factor of hardening besides increasing the density of deformation defects. It was found that uniform compression realized under higher pressures leads to less hardening and less accumulation of deformation defects. This associated with activation of recovery processes
Multipole modes in deformed nuclei within the finite amplitude method
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...
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...
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)
Directory of Open Access Journals (Sweden)
V. I. Semenov
2011-06-01
Full Text Available This paper presents the results of tribological investigations conducted on steel 20 with the carbon content of up to 0.2%. The steel was studied in the three conditions: initial (hot-rolled, after heat-treatment (quenching+tempering and after heat treatment with subsequent severe plastic deformation (SPD performed by equal channel angular pressing technique (ECAP. It was stated that after various treatments the material acquires various structural conditions and possesses various strength properties and has a considerable difference in oxygen content in the surface layer. This influences the tribological properties during the contact with tool steel. The lowest values of adhesive bond shear strength, friction coefficient and wear rate are demonstrated in the material after martempering with subsequent SPD by ECAP technique. The surface of the investigated material after SPD treatment by the ECAP technique possesses a highest bearing capacity and requires more time for wearing-in in friction assemblies. Oxygen content increase in the form of metal oxides on the surface of low-carbon steels is accompanied by a decrease of the adhesive component of friction coefficien.
Enhanced magnetic properties and bending strength of hot deformed Nd-Fe-B magnets with Cu additions
International Nuclear Information System (INIS)
Commercial rapidly-quenched Nd-Fe-B ribbons blended with fine Cu powders (10-30 ?m) were hot pressed to obtain fully dense magnets and then die upset into highly anisotropic, oriented magnets. The effects of Cu addition on the magnetic properties and bending strength of hot deformed Nd-Fe-B magnets were investigated. It was found that the coercivity (Hcj) and maximum energy product (BH)max as well as the bending strength were enhanced significantly by Cu addition. Detailed microstructural investigations were carried out by transmission electron microscopy/high-resolution transmission electron microscopy (TEM/HRTEM). It shows that there are two types of grain boundaries in Cu-doped magnet, one is parallel and the other is trigonal. However, energy dispersive X-rays (EDX) analyses indicate that the two type intergranular phases are NdCu2. Analyses indicate that the enhanced texture of Cu-doped magnet is due to the lower melting point of the intergranular phase, leading to the enhancement in magnetic properties. Improvement of bending stress in Cu-doped magnet is related to the trigonal grain boundaries and the rheology of the intergranular phase.
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.
Design, fabrication and cold tests of a superferritic octupole corrector for the LHC
International Nuclear Information System (INIS)
In the correction scheme of the LHC it is planned to install octupole corrector magnets in the short straight section of the lattice. Initially these correctors were distributed windings on the cold bore tube nested in the tuning quadrupoles. The latter being suppressed a new compact superferric design was chosen for the octupole prototype, suitable for a two-in-one configuration. This prototype was designed by CERN and CEDEX/Spain, built at INDAR/Spain and tested at CEDEX. The paper reports on the design of the prototype, describes the fabrication and assembly and presents the measurement results. Special interest has been taken to design a simple and compact magnet, easy to fabricate and training free below nominal field. First results show the feasibility of the solution which will be finally confirmed by magnetic measurements
Design, fabrication and cold tests of a super ferric octupole corrector for the LHC
International Nuclear Information System (INIS)
In the corrections scheme of the LHC it is planed to install octupole corrector magnets in the short straight section of the lattice. Initially these correctors were distributed windings on the cold bore tube nested in the tuning quadrupoles. The latter being suppressed a new compact super ferric design was chosen for the octupole prototype, suitable for a two-in-one configuration. This prototype was designed by CERN and CEDEX/Spain, built at INDAR/Spain and tested at CEDEX. The paper reports on the design of the prototype, describes the fabrication and assembly and presents the measurement results. Special interest has been taken to design a simple and compact magnet, easy to fabricate and training free below nominal field. First results show the feasibility of the solution wich will be finally confirmed by magnetic measurement. (Author) 4 refs
Design, fabrication and cold tests of a superferritic octupole corrector for the LHC
Energy Technology Data Exchange (ETDEWEB)
Laurent, G.; Russenschuck, S.; Siegel, N.; Traveria, M. [CERN, Geneva (Switzerland); Garcia-Tabares, L.; Calero, J. [CEDEX-MOPTMA, Madrid (Spain); Aguirre, P.; Etxeandia, J.; Garcia, J. [INDAR, Beasain (Spain)
1996-07-01
In the correction scheme of the LHC it is planned to install octupole corrector magnets in the short straight section of the lattice. Initially these correctors were distributed windings on the cold bore tube nested in the tuning quadrupoles. The latter being suppressed a new compact superferric design was chosen for the octupole prototype, suitable for a two-in-one configuration. This prototype was designed by CERN and CEDEX/Spain, built at INDAR/Spain and tested at CEDEX. The paper reports on the design of the prototype, describes the fabrication and assembly and presents the measurement results. Special interest has been taken to design a simple and compact magnet, easy to fabricate and training free below nominal field. First results show the feasibility of the solution which will be finally confirmed by magnetic measurements.
Measurements of octupole collectivity in Rn and Ra nuclei using Coulomb excitation
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.
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
Mixed-symmetry octupole and hexadecapole excitations in the N=52 isotones
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...
Indication for a K/sup ?/ = 0- octupole band in 150Nd from electron scattering
International Nuclear Information System (INIS)
Recent electron scattering results on the 0.850 MeV level of 150Nd, when analyzed in terms of the interacting boson model, are inconsistent with the interpretation of this level as a pure J/sup ?/(K) = 2+(0) state. Very recent (n,n'?) work has shown this level to be a 1-, 2+ doublet. Assuming this level to be the band head of a ''K/sup ?/ = 0-'' octupole band, a simple model is used to predict electron scattering form factors for the 0.850 MeV state and a 3- octupole level observed at 0.931 MeV. Comparison is made between these predicted form factors and recent electron scattering data
Spin-controlled octupole-shape transition in 224Ra: a microscopic description
Yao, J M; Li, Z P
2015-01-01
We report the first beyond-mean-field study of low-lying parity-doublet states in 224Ra by extending the multireference relativistic energy density functional method to include dynamical correlations related to symmetry restoration and quadrupole-octupole shape fluctuation with a generator coordinate method combined with parity, particle-number, and angular-momentum projections. We clarify full microscopically that there is a novel spin-controlled phase transition from dynamical octupole shapes to a stable one, where the dominated shape of positive-parity states drifts gradually to that of negative-parity states. This transition is characterized by the gradually reduced odd-even staggering in the excitation energies of parity doublets when approaching the transition from below.
Directory of Open Access Journals (Sweden)
P. Lacková
2015-01-01
Full Text Available The aim had been to study changes in the properties of aluminium alloy AlSiMgMn. Influence of SPD of the mechanical properties had increased (Rm by 86 MPa, Ro0,2 by 175 MPa, while A had decreased to 20 %. The corrosion potentials had been evaluated in the environment of H2O and in SARS. After SPD was observed in the environment of H2O, that resistance had increased by -218 mV and after exposure up to 1 000 min there was a slight deterioration of resistance in SARS. On the surface specimens after SPD were observed higher quantities of corrosion products. After SPD was observed fatigue characteristics in torsional stress in the oblique branches Wohler curves showed favourable characteristics of about 35 %.
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)
Muon Knight shift measurements in possible octupole ordering system SmRu4P12
International Nuclear Information System (INIS)
We performed muon Knight shift measurements on randomly aligned single crystalline samples of SmRu4P12 in a magnetic field of 6 T. A marked increase in the muon spin relaxation rate was observed below a metal-insulator transition temperature, interpreted as an occurrence of finite local fields due to a dipole and/or octupole ordering. An expected magnetic anomaly at around 14 K in high fields was still obscure in a field of 6 T
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".
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.)
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.
Wang, Haopeng
With the recent advances in processing and catalyst technology, novel morphologies have been created in crystalline polymers and they are expected to substantially impact the properties. To reveal the structure-property relationships of some of these novel polymeric systems becomes the primary focus of this work. In the first part, using an innovative layer-multiplying coextrusion process to obtain assemblies with thousands of polymer nanolayers, dominating "in-plane" lamellar crystals were created when the confined poly(ethylene oxide) (PEO) layers were made progressively thinner. When the thickness was confined to 25 nanometers, the PEO crystallized as single, high-aspect-ratio lamellae that resembled single crystals. This crystallization habit imparted more than two orders of magnitude reduction in the gas permeability. The dramatic decrease in gas permeability was attributed to the reduced diffusion coefficient, because of the increase in gas diffusion path length through the in-plane lamellae. The temperature dependence of lamellar orientation and the crystallization kinetics in the confined nanolayers were also investigated. The novel olefinic block copolymer (OBC) studied in the second part consisted of long crystallizable sequences with low comonomer content alternating with rubbery amorphous blocks with high comonomer content. The crystallizable blocks formed lamellae that organized into space-filling spherulites even when the fraction of crystallizable block was so low that the crystallinity was only 7%. These unusual spherulites were highly elastic and recovered from strains as high as 300%. These "elastic spherulites" imparted higher strain recovery and temperature resistance than the conventional random copolymers that depend on isolated, fringed micellar-like crystals to provide the junctions for the elastomeric network. In the third part, positron annihilation lifetime spectroscopy (PALS) was used to obtain the temperature dependence of the free volume hole size in propylene/ethylene copolymers over a range in comonomer content. Above the glass transition temperature (Tg), the reduced free volume hole size and the densification of the amorphous phase were attributed to constraint imposed on rubbery amorphous chain segments by attached chain segments in crystals. However constant free volume fraction was found at Tg, across the crystallinity range of the copolymers, in agreement with the iso-free volume concept of glass transition.
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.
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
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.)
Tetrahedral and Triangular Deformations of $Z=N$ Nuclei in Mass Region $A \\sim 60-80$
Takami, S; Matsuo, M
1998-01-01
We study static non-axial octupole deformations in proton-rich $Z=N$ nuclei, $^{64}$Ge, $^{68}$Se, $^{72}$Kr, $^{76}$Sr, $^{80}$Zr and $^{84}$Mo, by using the Skyrme Hartree-Fock plus BCS calculation with no restrictions on the nuclear shape. The calculation predicts that the oblate ground state in $^{68}$Se is extremely soft for the $Y_{33}$ triangular deformation, and that in $^{80}$Zr the low-lying local minimum state coexisting with the prolate ground state has the $Y_{32}$ tetrahedral deformation.
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)
Choudhary, S.; Qureshi, S.
2011-01-01
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, semicond...
Lifetimes of excited states in octupole-collective 142,144Ba nuclei
International Nuclear Information System (INIS)
Lifetimes of excited states have been measured for the positive-parity rotational bands in neutron-rich 142,144Ba as well as the 7- and 9- states of the negative-parity band in 144Ba using the differential Doppler shift method. The deduced quadrupole moment, Qt, of the positive-parity band decreases with angular momentum and overall shows good agreement with earlier measurements. The measured lifetimes of 7- and 9- states are used to determine the electric dipole moment, D0=0.17(3) and 0.09(1) e fm, respectively, in the negative-parity octupole band of 144Ba
Sarriguren, P
2015-01-01
Beta-decay properties of even and odd-A neutron-rich Ge, Se, Kr, Sr, Ru, and Pd isotopes involved in the astrophysical rapid neutron capture process are studied within a deformed proton-neutron quasiparticle random-phase approximation. The underlying mean field is described self-consistently from deformed Skyrme Hartree-Fock calculations with pairing correlations. Residual interactions in the particle-hole and particle-particle channels are also included in the formalism. The isotopic evolution of the various nuclear equilibrium shapes and the corresponding charge radii are investigated in all the isotopic chains. The energy distributions of the Gamow-Teller strength as well as the beta-decay half-lives are discussed and compared with the available experimental information. It is shown that nuclear deformation plays a significant role in the description of the decay properties in this mass region. Reliable predictions of the strength distributions are essential to evaluate decay rates in astrophysical scenari...
International Nuclear Information System (INIS)
We have developed multi-dimensional constrained covariant density functional theories (MDC-CDFT) for finite nuclei in which the shape degrees of freedom ??? with even ?, e.g., ?20, ?22, ?30, ?32, ?40, etc., can be described simultaneously. The functional can be one of the following four forms: the meson exchange or point-coupling nucleon interactions combined with the non-linear or density-dependent couplings. For the pp channel, either the BCS approach or the Bogoliubov transformation is implemented. The MDC-CDFTs with the BCS approach for the pairing (in the following labelled as MDC-RMF models with RMF standing for 'relativistic mean field') have been applied to investigate multi-dimensional potential energy surfaces and the non-axial octupole Y32-correlations in N = 150 isotones. In this contribution we present briefly the formalism of MDC-RMF models and some results from these models. The potential energy surfaces with and without triaxial deformations are compared and it is found that the triaxiality plays an important role upon the second fission barriers of actinide nuclei. In the study of Y32-correlations in N = 150 isotones, it is found that, for 248Cf and 260Fm, ?32 > 0.03 and the energy is lowered by the ?32 distortion by more than 300 keV; while for 246Cm and 252No, the pocket with respect to ?32 is quite shallow.
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.
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.
Kozin, Scott H; Zlotolow, Dan A
2015-10-01
Madelung deformity of the wrist is more common in females and is often associated with Leri Weill dyschondrosteosis, a mesomelic form of dwarfism. Patients with Madelung deformity often report wrist deformity resulting from the prominence of the relatively long ulna. The typical Madelung deformity is associated with a Vickers ligament that creates a tether across the volar-ulnar radial physis that restricts growth across this segment. The distal radius deforms in the coronal (increasing radial inclination) and the sagittal (increasing volar tilt) planes. There is lunate subsidence and the proximal carpal row adapts to the deformity by forming an upside-down pyramid shape or triangle. Treatment depends on the age at presentation, degree of deformity, and magnitude of symptoms. Mild asymptomatic deformity warrants a period of nonsurgical management with serial x-ray examinations because the natural history is unpredictable. Many patients never require surgical intervention. Progressive deformity in the young child with considerable growth potential remaining requires release of Vickers ligament and radial physiolysis to prevent ongoing deterioration Concomitant ulnar epiphysiodesis may be necessary. Advanced asymptomatic deformity in older children with an unacceptable-appearing wrist or symptomatic deformity are indications for surgery. A dome osteotomy of the radius allows 3-dimensional correction of the deformity. Positive radiographic and clinical results after dome osteotomy have been reported. PMID:26341718
Measurement of reduced electric octupole transition probabilities B(E3;O1+ ? 31-), for 118,120,122Sn
International Nuclear Information System (INIS)
Values of reduced electric octupole transition probabilities B(E3;O1+ ? 31-) for the nuclides 118,120,122Sn have been determined using Coulomb excitation with 12C projectiles. The results are in good agreement with shell-model calculations made without introducing effective charges but involving core excitations. Values for B(E2;O1+ ? 21+) are also presented
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.
International Nuclear Information System (INIS)
This paper presents experimental results on intermittent electromagnetic radiation during plastic deformation of Cu-Ni alloys under tension and compression modes of deformation. On the basis of the nature of electromagnetic radiation signals, oscillatory or exponential, results show that the compression increases the viscous coefficient of Cu-Ni alloys during plastic deformation. Increasing the percentage of solute atoms in Cu-Ni alloys makes electromagnetic radiation strength higher under tension. The electromagnetic radiation emission occurs at smaller strains under compression showing early onset of plastic deformation. This is attributed to the role of high core region tensile residual stresses in the rolled Cu-Ni alloy specimens in accordance with the Bauschinger effect. The distance between the apexes of the dead metal cones during compression plays a significant role in electromagnetic radiation parameters. The dissociation of edge dislocations into partials and increase in internal stresses with increase in solute percentage in Cu-Ni alloys under compression considerably influences the electromagnetic radiation frequency.
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).
Collective motion in system with general multipolar-deformations
International Nuclear Information System (INIS)
A general formalism is given for the collective motion in a system with general multipolar-deformations, which is treated as vibrations in body-fixed frame and rotation of whole system about the axes of Lab-system, as well as the coupling between vibrations and rotation. 18 various body - fixed frames are defined for octupole deformed system, which shows they can be put into 9 various classifies and the determinants of metric matrix in the body-fixed frames defined by the variables a30, a31, a32 , b31 and a30, a31, b31, b32 are 9a322 and 9b322, which are the simplest
q-Deformed Dynamics and Virial Theorem
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.
International Nuclear Information System (INIS)
We study null 1/4 BPS deformations of flat domain wall solutions (NDDW) in N = 2, d = 5 gauged supergravity with hypermultiplets and vector multiplets coupled. These are uncharged time-dependent configurations and contain as special case, 1/2 supersymmetric flat domain walls (DW), as well as 1/2 BPS null solutions of the ungauged supergravity. Combining our analysis with the classification method initiated by Gauntlett et al., we prove that all the possible deformations of the DW have origin in the hypermultiplet sector or/and are null. Here, we classify all the null deformations: we show that they naturally organize themselves into 'gauging' (v-deformation) and 'non gauging' (u-deformation). They have different properties: only in presence of v-deformation is the solution supported by a time-dependent scalar potential. Furthermore we show that the number of possible deformations equals the number of matter multiplets coupled. We discuss the general procedure for constructing explicit solutions, stressing the crucial role taken by the integrability conditions of the scalars as spacetime functions. Two analytical solutions are presented. Finally, we comment on the holographic applications of the NDDW, in relation to the recently proposed time-dependent AdS/CFT
Celi, A
2007-01-01
We study null 1/4 BPS deformations of flat Domain Wall solutions (NDDW) in N=2, d=5 gauged supergravity with hypermultiplets and vector multiplets coupled. These are uncharged timedependent configurations and contain as special case, 1/2 supersymmetric flat domain walls (DW) and, as well, 1/2 BPS null solutions of the ungauged supergravity. Combining our analysis with the classification method initiated by Gauntlett et al., we prove that all the possible deformations of the DW have origin in the hypermultiplet sector or/and are null. Here, we classify all the null deformations: we show that they naturally organize in "gauging" (v-deformation) and "non gauging" (u-deformation). They have different properties: only in presence of v-deformation the solution is supported by a timedependent scalar potential. Furthermore we show that u-deformation forces the number of multiplets coupled to be different by one. We discuss the general procedure for constructing explicit solutions, stressing the crucial role taken by ...
Appraising nuclear octupole moment contributions to the hyperfine structures in $^{211}$Fr
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...
International Nuclear Information System (INIS)
The QPNM equations are derived taking account of p-h and p-p interactions. The calculated quadrupole, octupole and hexadecapole vibrational states in 168Er, 172Yb and 178Hf are found to be reasonale agreement with experimental data. It is shown that distribution of the E? strength in some deformed nuclei differs from the standard one. There are cases when for a given K? and E? strength is concentrated not on the first but on higher-lying states. The assertion made earlier about the absence of collective two-phonon states in deformed nuclei is confirmed. 44 refs.; 1 fig.; 6 tabs
Deformation properties of AlTi2C particle containing Ti-46Al-2Cr-2Nb alloys at 1,000 to 1,200 K
International Nuclear Information System (INIS)
This paper reports the 1,000--1,200 K slow plastic deformation properties of TiC-modified Ti-48Al-2Cr-2Nb materials and compares their values with those of other TiAl-based alloys. Ti-46Al-2Cr-2Nb has been alloyed with TiC in an attempt to improve the 1,000--1,200 K strength by the formation of AlTi2C precipitates in a lamellar matrix. While the addition of 6 wt.% TiC does improve strength under lower temperature or faster test conditions, at higher temperatures or lower strain rates the base Ti-46Al-2Cr2Nb alloy has better properties than the TiC modifications
Energy Technology Data Exchange (ETDEWEB)
Whittenberger, J.D. [Max-Planck-Inst. fuer Metallforschung, Stuttgart (Germany). Inst. fuer Werkstoffwissenschaft; Ray, R. [Marko Materials Inc., North Billerica, MA (United States)
1995-11-01
This paper reports the 1,000--1,200 K slow plastic deformation properties of TiC-modified Ti-48Al-2Cr-2Nb materials and compares their values with those of other TiAl-based alloys. Ti-46Al-2Cr-2Nb has been alloyed with TiC in an attempt to improve the 1,000--1,200 K strength by the formation of AlTi{sub 2}C precipitates in a lamellar matrix. While the addition of 6 wt.% TiC does improve strength under lower temperature or faster test conditions, at higher temperatures or lower strain rates the base Ti-46Al-2Cr2Nb alloy has better properties than the TiC modifications.
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
DEFF Research Database (Denmark)
Tabrizian-Ghalehno, Naja; Hansen, Hans NØrgaard
2010-01-01
Influence of cold forging, and subsequent heat treatment and diamond turning on optical quality of anodized film on 6060 (AlMgSi) alloy was investigated and compared with microstructural changes. Heat treatment of the samples was carried out either prior to forging, post-forging, or both. The surface of the forged material was then diamond turned to a mirror like finish. The diamond turned samples were subsequently anodized in a sulphuric acid bath. The microstructure of the samples was analysed using optical microscopy (LOM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Colour/brightness measurements were carried out using CIE Lab system. An optical method was used to measure the thickness of the oxide film and roughness of the surface was measured before and after anodizing using stylus, a mechanical instrument, and bidirectional reflection distribution function (BRDF), an optical instrument. Results indicated that the post-forging heat treatment had a great influence on the appearance of the anodized layer, which was also a function of the deformation introduced prior to heat treatment. The effect was assumed to be attributed to the change in microstructure, especially the distribution and the amount of the intermetallic particles such as elemental Si and Mg2Si. Roughness of the oxide film was also found to be a function of the heat treatment and deformation condition.
Di-neutron correlation in soft octupole excitations of neutron-rich Ni isotopes beyond N=50
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...
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.)
High-temperature deformation behavior and thermal properties of an Ni30Co17Fe53 alloy
Energy Technology Data Exchange (ETDEWEB)
Lee, Kwang Seok; Yoon, Dong Hyun [Korea Institute of Materials Science, Changwon (Korea, Republic of). Materials Deformation Group; Jung, Joong Eun; Chang, Young Won [POSTECH, Pohang (Korea, Republic of). Dept. of Materials Science and Engineering; Lee, Jung Hwan [Korea Institute of Materials Science, Changwon (Korea, Republic of). Technical Support Div.
2012-07-15
High temperature deformation behavior of a Ni30Co17Fe53 alloy has been investigated by carrying out hot compression tests at temperatures ranging from 600 C to 1 150 C under strain rates between 10{sup -5} and 1 s{sup -1}. Both the temperature and strain-rate dependence of the flow stress were found to be described by a hyperbolic sine function. Hot formability of this alloy was also estimated by constructing an empirical processing map based on a dynamic materials model, from which the region with high power dissipation efficiency was exhibited as a feasible combination of processing condition at around 1 150 C and 10{sup -2}s{sup -1}. Three different thermo-mechanical treatment processes were adopted for hot-forging to investigate its influence on microstructure and subsequent thermal expansion and thermal conductivity. (orig.)
Properties of the rotational bands in 161Er
International Nuclear Information System (INIS)
High-spin states in 161Er have been studied experimentally using the 150Nd(16O,5n) reaction at a beam energy of 86 MeV. The 5/2+[642], 3/2-[521], and 11/2-[505] bands are extended up to high-spin states, and particularly the ?=-1/2 branch of the ground state 3/2-[521] band is revised significantly. The relatively enhanced E1 transitions from the 3/2-[521] band to the 5/2+[642] band are observed. The band properties are analyzed within the framework of a triaxial particle-rotor model, and near-prolate shape and triaxial deformation are proposed to the 3/2-[521] and 5/2+[642] bands, respectively. Signature inversion occurs in the 3/2-[521] band after the band crossing in 161Er, and the systematics of the signature inversion associated with the 3/2-[521] configuration are discussed. By analyzing the properties of the relatively enhanced E1 transitions, it is found that the R(E1/E2) values show angular momentum dependence before the band crossing, and these enhanced E1 transitions could be attributed to octupole softness.
Lin, Fu-Shiong; Starke, E. A.; Gysler, A.
1984-10-01
The Ti-6Al-2Nb-lTa-0.8Mo alloy was processed to develop both near-basal and transverse textures. Samples were annealed at different temperatures to vary the equiaxed alpha grain size and the thick-ness of the grain boundary beta, and subsequently quenched in order to transform the beta phase to either martensite, tempered martensite, or Widmanstätten alpha + beta. The effect of microstructure and texture on tensile properties and on fracture toughness was investigated. In addition, yield locus diagrams were constructed in order to study the texture strengthening effect. The yield strength was found to be strongly dependent on the thickness and Burgers relationship of the transformed beta phase surrounding the alpha grains. A texture hardening effect as large as 60 pct was found for the basal-texture material but only 15 pct for the transverse texture material. These variations are asso-ciated with differences in deformation behavior.
Li, Wei; Li, Lanlan; Nan, Yun; Xu, Zhenyu; Zhang, Xiangyi; Popov, A. G.; Gunderov, D. V.; Stolyarov, V. V.
2008-07-01
A high number density (˜1023 m-3) of ?-Fe nanocrystals with a size below 10 nm has been induced in amorphous Nd9Fe85B6 by high-pressure torsion deformation (HPTD) at room temperature. The amorphous Nd9Fe85B6 subjected to HPTD presents a quite different crystallization behavior as compared with the nondeformed alloy. The growth activation energies Eg=0.9 eV for ?-Fe nanocrystals and 0.5 eV for Nd2Fe14B nanocrystals are determined from the annealing time dependence of their size. The ?-Fe/Nd2Fe14B nanocomposite magnets prepared by the combination of HPTD and subsequent thermal annealing show enhanced magnetic properties due to a small grain size as compared with the magnets prepared by directly annealing amorphous Nd9Fe85B6.
Search for two-phonon octupole vibrational bands in 88,89,92,93,94,96Sr and 95,96,97,98Zr
International Nuclear Information System (INIS)
Several new gamma transitions were identified in 94Sr, 93Sr, 92Sr, 96Zr and 97Zr from the spontaneous fission of 252Cf. Excited states in 88,89,92,94,96Sr and 95,96,97,98Zr were reanalyzed and reorganized to propose the new two-phonon octupole vibrational states and bands. The spin and parity of 6+ are assigned to a 4034.5 keV state in 94Sr and 3576.4 keV state in 98Zr. These states are proposed as the two-phonon octupole vibrational states along with the 6+ states at 3483.4 keV in 96Zr, at 3786.0 keV in 92Sr and 3604.2 keV in 96Sr. The positive parity bands in 88,94,96Sr and 96,98Zr are the first two-phonon octupole vibrational bands based on a 6+ state assigned in spherical nuclei. It is thought that in 94,96Sr and 96,98Zr a 3- octupole vibrational phonon is weakly coupled to an one-phonon octupole vibrational band to make the two-phonon octupole vibrational band. Also, the high spin states of odd-A95Zr and 97Zr are interpreted to be generated by the neutron 2d5/2 hole and neutron 1g7/2 particle, respectively, weakly coupled to one- and two-phonon octupole vibrational bands of 96Zr. The high spin states of odd-A87Sr are interpreted to be caused by the neutron 1g9/2 hole weakly coupled to 3- and 5- states of 88Sr. New one- and two-POV bands in 95,97Zr and 87,89Sr are proposed, for the first time, in the present work. (author)
Energy Technology Data Exchange (ETDEWEB)
Moteff, J.
1977-07-08
Transmission electron microscopy used to evaluate the deformation (creep, fatigue and tensile) induced microstructure of 304 SS, Incoloy 800, 330 SS and three of the experimental alloys (E19, E23 and E36) obtained from the National Alloy Program clearly shows that the relationship between the subgrain size (lambda) and the applied stress (sigma) obeys the equation lambda = Ab (sigma/E)/sup -1/ where A is a constant of the order of 4, b the Burgers rector and E is Young's modulus. Hot-hardness studies on 304 SS, 316 SS, Incoloy 800, 2 /sup 1///sub 4/ Cr-1 Mo steels, 330 SS, Inconel 718, PE-16, Inconel 706, M-813 and the above three experimental alloys suggests that reasonable effective activation energies for creep may be obtained through the use of the hardness test as a strength microprobe tool. The ordering of the strength levels obtained through hot-hardness follows quite closely that obtained in tensile tests when those data are available.
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
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.
International Nuclear Information System (INIS)
A commercial purity aluminum was highly deformed by the accumulative roll-bonding (ARB) process and subsequently annealed. The specimens having various grain size distributions were obtained. In case of the specimen ARB-processed with lubrication, the specimens with mean grain size larger than 3?m showed continuous yielding. On the other hand, in case of the specimen ARB-processed without lubrication, the specimens with mean grain size larger than 3?m showed discontinuous yielding. It suggests that appearance of the yield-drop phenomena can not be decided by the mean grain size. In order to consider effect of grain size distribution, the volume fraction of grains was summed from coarser grains, and the grain size when the summed volume fraction reached 70%, d70% was estimated from the grain size distribution. it was found that d70% of specimens which showed continuous yielding were larger than 8 ?m while the specimens which showed discontinuous yielding were smaller than 6 ?m, regardless of the lubrication condition in the ARB process. The result suggests that the appearance of the yield-drop phenomena depend on d70%.
Core breaking and octupole low-spin states in $^{207}$ Tl
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.
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
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.
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
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.
International Nuclear Information System (INIS)
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, WSTZ, calculated using the cooperative shear model, is equivalent to the activation energy for ?-relaxation, E?. This result suggested that the fundamental process for STZ activation is the mechanically activated ?-relaxation. Since the E? value and the glass transition temperature Tg of BMGs have a linear relation, that is, because E????26RTg, the composition of the BMG determines the ease with which the STZ can be activated. Enthalpy relaxation experiments revealed that the BMG Zr50Cu40Al10 when deformed by high-pressure torsion (HPT) has a lower E? 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 WSTZ 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? (or WSTZ) and result in improvements in the mechanical properties of the BMG.
Adachi, Nozomu; Todaka, Yoshikazu; Yokoyama, Yoshihiko; Umemoto, Minoru
2014-09-01
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, WSTZ, calculated using the cooperative shear model, is equivalent to the activation energy for ?-relaxation, E?. This result suggested that the fundamental process for STZ activation is the mechanically activated ?-relaxation. Since the E? value and the glass transition temperature Tg of BMGs have a linear relation, that is, because E? ? 26RTg, the composition of the BMG determines the ease with which the STZ can be activated. Enthalpy relaxation experiments revealed that the BMG Zr50Cu40Al10 when deformed by high-pressure torsion (HPT) has a lower E? 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 WSTZ 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? (or WSTZ) and result in improvements in the mechanical properties of the BMG.
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.
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.)
Measurements of octupole collectivity in $^{220,222}$Rn and $^{222,224}$Ra using Coulomb excitation
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.
Glezer, A. M.; Tomchuk, A. A.; Rassadina, T. V.
2015-04-01
The effect of the fraction and the scheme of deformation under high quasi-hydrostatic pressure in a Bridgman cell at room temperature and on the structure and the microhardness of commercial-purity iron is studied. Deformation is performed by one continuous or portioned loading to the same total strain. The number of cycles and the direction of rotation of the lower movable anvil are varied. It is determined that the number of revolutions and the direction of rotation considerably affect the sizes of the deformation-induced fragments and the recrystallized grains formed upon megaplastic deformation. The correlation between the structure parameters and the microhardness is analyzed.
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.
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.
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...
Magnetic octupole order in Ce0.7La0.3B6: A polarized neutron diffraction study
International Nuclear Information System (INIS)
Recently, in phase IV of CexLa1-xB6, weak but distinct superlattice reflections from the order parameter of phase IV have been detected by our unpolarized neutron scattering experiment [K. Kuwahara, K. Iwasa, M. Kohgi, N. Aso, M. Sera, F. Iga, J. Phys. Soc. Japan 76 (2007) 093702]. The scattering vector dependence of the intensity of superlattice reflections is quite unusual; the intensity is stronger for high scattering vectors. This result strongly indicates that the order parameter of phase IV is the magnetic octupole. However, the possibility that the observed superlattice reflections are due to lattice distortions could not be completely ruled out only on the basis of the unpolarized neutron scattering experiment. To confirm that the superlattice reflections are magnetic, therefore, we have performed a single crystal polarized neutron diffraction experiment on Ce0.7La0.3B6. The obtained result has clearly shown that the time reversal symmetry is broken by the order parameter of phase IV. This is further evidence for the magnetic octupole order in CexLa1-xB6.
International Nuclear Information System (INIS)
CERN is preparing for the construction of the Large Hadron Collider (LHC) to be installed in the LEP tunnel. The magnetic lattice of the LHC will consist of a ring of twin aperture dipoles and quadrupoles, connected electrically in series. To adjust the working point of the machine, so called tuning quadrupoles will be installed in pairs in each regular cell, next to the main quadrupoles. Also, to correct multipolar field errors in the LHC, an octupole correction winding is required near each lattice quadrupole. A nested construction of these two magnets is foreseen. As part of the LHC R and D program, CERN and ACICA (a group of five Spanish industries: Abengoz, Canzler, Indar, Cenemesa and AME; since June 1990 Cenemesa is part of ABB Spain), signed a common development agreement for the design, fabrication and testing of a prototype tuning quadrupole and octupole corrector. This paper describes the design of these magnets, giving details of magnetic and mechanical calculations, including results from existing and specially developed computer codes, and model work. Further, the construction procedures are described, including the facilities and tooling developed by ACICA for this work
Energy Technology Data Exchange (ETDEWEB)
Luo, Y.X. [Physics Department, Vanderbilt University, Nashville, TN 37235 (United States); Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)], E-mail: yxluo@lbl.gov; Rasmussen, J.O. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Hamilton, J.H.; Ramayya, A.V.; Liu, S.H.; Jones, E.F.; Gore, P.M.; Goodin, C. [Physics Department, Vanderbilt University, Nashville, TN 37235 (United States); Stone, N.J. [Department of Physics, Oxford University, Oxford OX1 3PU (United Kingdom); Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States); Zhu, S.J. [Physics Department, Vanderbilt University, Nashville, TN 37235 (United States); Physics Department, Tsinghua University, Beijing 100084 (China); Hwang, J.K.; Li, Ke; Crowell, H.L. [Physics Department, Vanderbilt University, Nashville, TN 37235 (United States); Lee, I.Y. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Ter-Akopian, G.M. [Flerov Laboratory for Nuclear Reactions, JINR, Dubna (Russian Federation); Daniel, A.V. [Physics Department, Vanderbilt University, Nashville, TN 37235 (United States); Flerov Laboratory for Nuclear Reactions, JINR, Dubna (Russian Federation); Joint Institute for Heavy Ion Research, Oak Ridge, TN 37831 (United States); Stoyer, M.A. [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Donangelo, R. [Universidade Federal do Rio de Janeiro, CP 68528, RJ (Brazil); Ma, W.C. [Mississippi State University, Drawer 5167, Mississippi State, MS 39762 (United States); Cole, J.D. [Idaho National Laboratory, Bldg. IRCPL, MS2114, Idaho Falls, ID 83415 (United States)
2010-07-01
The level scheme of odd-Z neutron-rich {sup 141}Cs (Z=55, N=86) was extended and expanded and that of {sup 144}Cs (N=89) was identified for the first time by means of {gamma}-{gamma}-{gamma} coincidence measurements of prompt {gamma} rays in the spontaneous fission of {sup 252}Cf with Gammasphere. Spin/parity was assigned to the levels based on angular correlations and level systematics in {sup 141,143}Cs. Parity doublets characteristic of both simplex quantum number s=+i and s=-i were proposed in {sup 141}Cs. The tests by using rotational frequency ratio {omega}{sup -}(I)/{omega}{sup +}(I) imply octupole vibrations in {sup 141}Cs and {sup 143}Cs. B(E1)/B(E2) values and electric dipole moments D{sub 0} were calculated for {sup 141}Cs, and re-determined for {sup 143}Cs. It was found that B(E1)/B(E2) values of {sup 141}Cs are simplex-dependent and the average value is one order of magnitude larger than that of {sup 143}Cs, and the deduced dipole moment D{sub 0} of {sup 141}Cs is considerably larger than that of {sup 143}Cs, and comparable to the N=86 isotone {sup 142}Ba. For {sup 144}Cs the yrast sequence looks like a well-deformed rotational band, but no octupole band structure was identified in this nucleus. The overall variations of D{sub 0} in {sup 141,143,144}Cs exhibit a pronounced drop of dipole moment with increasing neutron number in this odd-Z isotopic chain, which may be analogous in nature to the quenching of D{sub 0} observed in even-even {sup 146}Ba (Z=56, N=90) and {sup 224}Ra (Z=88, N=136), and to the drop of D{sub 0} in the odd-Z neutron-rich {sup 147}La (Z=57, N=90) reported by our collaboration.
Milyukov, V.; Myasnikov, A.
2012-04-01
The Elbrus volcanic center is located on the northern slope of the main ridge of the Greater Caucasus. It includes Mount Elbrus, a double-top stratovolcano, and a number of small volcanic centers concentrated on its western flank. According to present understandings, the Elbrus volcano falls into the category of the so-called dormant volcanoes that become reactivated. It is a typical volcano of a continental type. During a number of years to study magmatic structures of the Elbrus volcano, their resonant properties and dynamics the new resonant method has been used. The idea of method is simple enough. Magmatic structures, being a resonator, upon incidence of a broadband powerful seismic signal generate the secondary seismic waves, having a set of resonant modes and containing information about physical and mechanical properties of structure inhomogeneities. These resonant modes are determined by geometrical parameters and elastic properties of the magma chamber as well as by magma properties. Estimation of the resonant parameters is based on the analysis of lithosphere deformations recorded by the wide-band Baksan laser interferometer-strainmeter with a 75-m armlength which is installed in the underground tunnel of the Baksan Neutrino Observatory, 20 km apart from Mt. Elbrus. Here we report the analysis of the teleseismic signals excited by seven mean-power earthquakes (the magnitude, as a rule, didn't exceed 6), that occurred within 2005-2010 in so-called "a near zone» of the volcano Elbrus (Elbrus resonant structures (magma chambers), at the same time, the energies of these moderate-power earthquakes are not enough to excite the free oscillations of the Earth. Spectral analysis revealed quite confidently 10 groups of resonance modes in the range of periods of 30 -150 s. In this group of the resonant modes, three modes are stand out with the periods of 62.1 s, 64.3 s, and 67.9 s, which are excited in 100% of seismic events. The intensities of these modes in the spectra are maximal, or close to the maximum. Estimates of Q-factor of the selected regional resonant modes lie in the range 250-300, that assumes that the revealed modes are generated by the structures containing magmatic fluids with a large gas component. The resonant parameters (frequencies and Q-factors of the resonant modes) we have found were interpreted in the framework of contemporary models of magma resonators. We estimated the depth and dimensions of the shallow magma chamber, as well as the properties of the magma fluid which are corroborated by available geological and geophysical evidence. Our interpretation of observational materials suggests that the intrachamber pressure seems to be rising owing to the advent of new portions of hot lava from a deep magma source. The stated approach provides a window to volcano dynamics and lays a foundation of the new "resonant" method for monitoring the state of volcano. This work is supported by the Russian Foundation for Basic Research.
Deformed aerogels in the superfluid 3He
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...
?-deformed gauge theory and ?-deformed gravity
International Nuclear Information System (INIS)
Noncommutative (deformed, quantum) spaces are deformations of the usual commutative space-time. They depend on parameters, such that for certain values of parameters they become the usual space-time. The symmetry acting on them is given in terms of a deformed quantum group symmetry. In this work we discuss two special examples, the ?-deformed space and the ?-deformed space. In the case of the ?-deformed space we construct a deformed theory of gravity. In the first step the deformed diffeomorphism symmetry is introduced. It is given in terms of the Hopf algebra of deformed diffeomorphisms. The algebra structure is unchanged (as compared to the commutative diffeomorphism symmetry), but the comultiplication changes. In the commutative limit we obtain the Hopf algebra of undeformed diffeomorphisms. Based on this deformed symmetry a covariant tensor calculus is constructed and concepts such as metric, covariant derivative, curvature and torsion are defined. An action that is invariant under the deformed diffeomorphisms is constructed. In the zeroth order in the deformation parameter it reduces to the commutative Einstein-Hilbert action while in higher orders correction terms appear. They are given in terms of the commutative fields (metric, vierbein) and the deformation parameter enters as the coupling constant. One special example of this deformed symmetry, the ?-deformed global Poincar e symmetry, is also discussed. In the case of the ?-deformed space our aim is the construction of noncommutative gauge theories. Starting from the algebraic definition of the ?-deformed space, derivatives and the deformed Lorentz generators are introduced. Choosing one particular set of derivatives, the ?-Poincar e Hopf algebra is defined. The algebraic setting is then mapped to the space of commuting coordinates. In the next step, using the enveloping algebra approach and the Seiberg-Witten map, a general nonabelian gauge theory on this deformed space is constructed. As a consequence of the deformed Leibniz rules for the derivatives used in the construction, the gauge field is derivative-valued. As in the ?-deformed case, in the zeroth order of the deformation parameter the theory reduces to its commutative analog and the higher order corrections are given in terms of the usual (commutative) fields. In this way the field content of the theory is unchanged, but new interactions appear. The deformation parameter takes the role of the coupling constant. For the special case of U(1) gauge theory the action for the gauge field coupled to fermionic matter is formulated and the equations of motion and the conserved current(s) are calculated. The ambiguities in the Seiberg-Witten map are discussed and partially fixed, and an effective action (up to first order in the deformation parameter) which is invariant under the usual Poincar e symmetry is obtained. (Orig.)
Properties of the distorted Kerr black hole
Abdolrahimi, Shohreh; Nedkova, Petya; Tzounis, Christos
2015-01-01
We investigate the properties of the ergoregion and the location of the curvature singularities for the Kerr black hole distorted by the gravitational field of external sources. The particular cases of quadrupole and octupole distortion are studied in detail. We also investigate the scalar curvature invariants of the horizon and compare their behaviour with the case of the isolated Kerr black hole. In a certain region of the parameter space the ergoregion consists of a compact region encompassing the horizon and a disconnected part extending to infinity. The curvature singularities in the domain of outer communication, when they exist, are always located on the boundary of the ergoregion. We present arguments that they do not lie on the compact ergosurface. For quadrupole distortion the compact ergoregion size is negatively correlated with the horizon angular momentum when the external sources are varied. For octupole distortion infinitely many ergoregion configurations can exist for a certain horizon angular...
Distributed actuator deformable mirror
Bonora, Stefano
2010-01-01
In this paper we present a Deformable Mirror (DM) based on the continuous voltage distribution over a resistive layer. This DM can correct the low order aberrations (defocus, astigmatism, coma and spherical aberration) using three electrodes with nine contacts leading to an ideal device for sensorless applications. We present a mathematical description of the mirror, a comparison between the simulations and the experimental results. In order to demonstrate the effectiveness of the device we compared its performance with the one of a multiactuator DM of similar properties in the correction of an aberration statistics. At the end of the paper an example of sensorless correction is shown.
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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)
Developing a Virtual Rock Deformation Laboratory
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
Energy Technology Data Exchange (ETDEWEB)
Akbari Mousavi, S.A.A., E-mail: akbarimusavi@ut.ac.ir [School of Metallurgy and Materials Engineering, University College of Engineering, University of Tehran, North Kargar Street, P.O. Box: 11155-4563, Tehran (Iran, Islamic Republic of); Bahadori, Sh. Ranjbar [School of Metallurgy and Materials Engineering, University College of Engineering, University of Tehran, North Kargar Street, P.O. Box: 11155-4563, Tehran (Iran, Islamic Republic of)
2011-01-25
Research highlights: {yields} Post annealing solve the softening problem occurred in repeated passes of TE. {yields} Post annealing decreased the coherent domain size of twist extruded sample. {yields} Post annealing increased the microstrain of twist extruded sample. {yields} Simple shear mode is the mechanism of deformation across the TE sample. {yields} The simple shear mechanism is disrupted by post annealing treatments. - Abstract: X-ray diffraction peak broadening analysis showed that performing a proper heat treatment between the twist extrusion passes of commercially pure copper decreased the coherent domain size and increased the microstrain. Moreover, SEM micrographs illustrated that annealed material contained new formed grains that could not grow due to lack of sufficient time. Under such circumstances, the ultimate strength was elevated about 45 MPa. The deformed material showed texture of simple shear deformation, changing by applying the post annealing.
International Nuclear Information System (INIS)
Research highlights: ? Post annealing solve the softening problem occurred in repeated passes of TE. ? Post annealing decreased the coherent domain size of twist extruded sample. ? Post annealing increased the microstrain of twist extruded sample. ? Simple shear mode is the mechanism of deformation across the TE sample. ? The simple shear mechanism is disrupted by post annealing treatments. - Abstract: X-ray diffraction peak broadening analysis showed that performing a proper heat treatment between the twist extrusion passes of commercially pure copper decreased the coherent domain size and increased the microstrain. Moreover, SEM micrographs illustrated that annealed material contained new formed grains that could not grow due to lack of sufficient time. Under such circumstances, the ultimate strength was elevated about 45 MPa. The deformed material showed texture of simple shear deformation, changing by applying the post annealing.
Plastic deformation of indium nanostructures
Energy Technology Data Exchange (ETDEWEB)
Lee, Gyuhyon [Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1 (Canada); Kim, Ju-Young [Division of Engineering and Applied Science, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Burek, Michael J. [Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1 (Canada); Greer, Julia R. [Division of Engineering and Applied Science, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Tsui, Ting Y., E-mail: tttsui@uwaterloo.ca [Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1 (Canada)
2011-07-25
Highlights: {yields} Indium nanopillars display two different deformation mechanisms. {yields} {approx}80% exhibited low flow stresses near that of bulk indium. {yields} Low strength nanopillars have strain rate sensitivity similar to bulk indium. {yields} {approx}20% of compressed indium nanopillars deformed at nearly theoretical strengths. {yields} Low-strength samples do not exhibit strength size effects. - Abstract: Mechanical properties and morphology of cylindrical indium nanopillars, fabricated by electron beam lithography and electroplating, are characterized in uniaxial compression. Time-dependent deformation and influence of size on nanoscale indium mechanical properties were investigated. The results show two fundamentally different deformation mechanisms which govern plasticity in these indium nanostructures. We observed that the majority of indium nanopillars deform at engineering stresses near the bulk values (Type I), with a small fraction sustaining flow stresses approaching the theoretical limit for indium (Type II). The results also show the strain rate sensitivity and flow stresses in Type I indium nanopillars are similar to bulk indium with no apparent size effects.
Plastic deformation effects on magnetic Barkhausen noise
International Nuclear Information System (INIS)
Plastically deformed steel specimens were analyzed using surface magnetic Barkhausen noise (MBN). Three types of samples were investigated: mild steel specimens uniaxially deformed up to 40% strain, mild steel specimens deformed in bending to 0.2% longitudinal strain, cold-rolled nuclear reactor pressure vessel steel specimens from 0% to 60% reduction ratio. The angular dependence of an 'MBNenergy' term was used to examine magnetic anisotropy changes with increasing deformation, with linear MBN scans used to monitor changes in magnetic properties along the specimen axis. Average MBNenergy values were observe to vary significantly with stress within the elastic region, yet only slightly in the plastic range of deformation. Changes in the shape of the pulse height distribution curves were evidence of plastic deformation effects on domain wall pinning sites. We conclude that a complex interplay between stress and strain mechanisms, residual stresses and crystallographic texture generates variations in MBN signal
Deformations of three-dimensional metrics
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.
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Single-crystal aluminium nanowires under torsion are studied using molecular dynamics simulations based on the many-body tight-binding potential. The effects of temperature, loading rate and nanowire length are evaluated in terms of atomic trajectories, potential energy, von Mises stress, a centrosymmetry parameter, torque, shear modulus and radial distribution function. Simulation results clearly show that torsional deformation begins at the surface, extends close to the two ends and finally diffuses to the middle part. The critical torsional angle which represents the beginning of plastic deformation varies with different conditions. Before the critical torsional angle is reached, the potential energy and the torque required for the deformation of a nanowire significantly increase with the torsional angle. The critical torsional angle increases with increasing nanowire length and loading rate and decreasing temperature. The torque required for the deformation decreases and the shear modulus increases with increasing nanowire length. For higher temperatures and higher loading rates, torsional buckling more easily occurs at the two ends of a nanowire, whereas it occurs towards the middle part at or below room temperature with lower loading rates. Geometry instability occurs before material instability (buckling) for a long nanowire. (paper)
International Nuclear Information System (INIS)
Structure, microhardness and electrical resistivity of the Cu–0.18% Zr alloy after high pressure torsion (HPT) were investigated for different initial states (hot-pressed, annealed, quenched) and deformation schedules. It is shown that HPT leads to formation of submicrocrystalline structure with the grain size of 200–250 nm. Studying of electrical resistivity of the Cu–0.18% Zr alloy showed that during HPT it increases with increasing the strain in comparison with initial not deformed state. It can be connected with changes of grain and subgrain structure, and also with processes of dissolution of particles of the second phase Cu5Zr during deformation. Decreasing of electrical resistivity values of Cu–0.18% Zr alloy after HPT during heating in the temperatures range of 250–400 °C and preservation or increase of microhardness values in this temperature interval reveal aging processes with allocation of Cu5Zr particles and confirm the fact of partial supersaturation of solid solution of copper with zirconium during deformation. Application of quenching, HPT and subsequent aging allows to achieve the maximum strengthening of the alloy
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\\,$\\times \\mu_N$.
Geometric Total Variation for Texture Deformation
DEFF Research Database (Denmark)
Bespalov, Dmitriy; Dahl, Anders Lindbjerg
2010-01-01
In this work we propose a novel variational method that we intend to use for estimating non-rigid texture deformation. The method is able to capture variation in grayscale images with respect to the geometry of its features. Our experimental evaluations demonstrate that accounting for geometry of features in texture images leads to significant improvements in localization of these features, when textures undergo geometrical transformations. Accurate localization of features in the presense of unkown deformations is a crucial property for texture characterization methods, and we intend to expoit this property for estimation of non-rigid deformations in our future work.
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.
Plastic deformation: Shearing mountains atom by atom
Energy Technology Data Exchange (ETDEWEB)
Müllner, Peter, E-mail: petermullner@boisestate.edu [Department of Materials Science and Engineering, Boise State University, Boise, ID 83725 (United States)
2013-11-15
Highlights: ? Rocks, wood, ceramics, semiconductors, and metals all deform in the same way, namely by heterogeneous shear banding via hierarchical orthogonal shear modes. ? While the governing principles of deformation are the same for rocks, wood, ceramics, semiconductors, and metals, these materialsdiffer in their microscopic deformation mechanisms and in the width of the shear band, which covers twelve orders of magnitude from angstroms to hundreds of meters. ? Microscopic deformation mechanisms couple to macroscopic deformation mechanisms, i.e. shear banding, through the collective properties of defect groups on the mesoscale. -- Abstract: Conventional wisdom established atomistic defects, dislocations, as agents of plastic deformation. On macroscopic scale, rock, wood, steel, tough ceramics, fiber reinforced composites, and silicon all deform in the same way and produce the same pattern; shear bands. The argumentation presented here, starts on the largest length scale of the problem at hand and leads through a number of hierarchical levels down to the atomistic mechanism. Shear bands develop discontinuously by the motion of a process zone. Locally, i.e. in the process zone, deformation proceeds perpendicularly to the macroscopic shear, in combination with a rotation. The microscopic shear itself may occur again in a discontinuous manner and again orthogonally to the intermediate level and so on at ever smaller scale. Material properties come into play at the highest hierarchical level, i.e. at the smallest length scale where they control the well-known micromechanisms.
Shell structures and chaos in deformed nuclei and large metallic clusters
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...
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 ...
Kommel, L.; Pokatilov, A.
2014-08-01
As-cast Cu-0.7wt% Cr and Cu-1.0wt% Cr alloys were subjected to equal-channel angular pressing (ECAP), hard cyclic viscoplastic (HCV) deformation and post deformation heat treatment for receiving an ultrafine grained material with a combination of high strength, good wear resistance and high electric conductivity. Samples from Cu-0.7wt% Cr alloy were processed up to six passes and Cu-1wt% Cr alloy samples were processed up to four passes of ECAP via Bc route. HCV deformation of samples was conducted by frequency of 0.5 Hz for 20 cycles at tension-compression strain amplitudes of +/-0.05%, +/-0.1%, +/-0.5%, +/-1% and +/-1.5%, respectively. During HCV deformation, as-cast Cu-0./wt% Cr alloy show fully viscoelastic behavior at strain/stress amplitude of +/-0.05% while ECAP processed material show the same behavior at strain amplitude of +/-0.1%. The Young modulus was increased from ~120 GPa up to ~150 GPa. The results illustrated that specific volume wear decrease with increasing of hardness but the measured coefficient of friction (COF ~ 0.6) was approximately the same for all samples at the end of wear testing. The hardness after ECAP for 6 passes by Bc route was 192HV0.1 and electric conduction 74.16% IACS, respectively. By this the as-cast Cu-0./wt% Cr alloy (heat treated at 1000 °C for 2h) has microhardness ~70HV0.1 and electrical conductivity of ~40% IACS. During aging at the temperatures in the interval of 250-550 °C for 1h the hardness and electrical conductivity were stabilized to mean values of 120+/-5HV0.1 and to 93.4+/-0.3% IACS, respectively. The hardness and electric conductivity took decrease by temperature increase over ~550 °C, respectively. The results of present experimental investigation show that UFG Cu- 0.7wt% Cr alloy with compare to Cu-1.0% Cr alloy is a highly electrical conductive and high temperature wear resistant material for using in electrical industry.
Deformations of crystal frameworks
Borcea, Ciprian S.; Streinu, Ileana
2011-01-01
We apply our deformation theory of periodic bar-and-joint frameworks to tetrahedral crystal structures. The deformation space is investigated in detail for frameworks modelled on quartz, cristobalite and tridymite.
Deformation Behavior of Human Dentin under Uniaxial Compression
Dmitry Zaytsev; Sergey Grigoriev; Peter Panfilov
2012-01-01
Deformation behavior of a human dentin under compression including size and rate effects is studied. No difference between mechanical properties of crown and root dentin is found. It is mechanically isotropic high elastic and strong hard tissue, which demonstrates considerable plasticity and ability to suppress a crack growth. Mechanical properties of dentin depend on a shape of samples and a deformation rate.
Boubekeur, Tamy; Sorkine, Olga; Schlick, Christophe
2007-01-01
In this sketch, we propose a system for applying interactive deformation on large models. This system is based on two new algorithms performing (pre-)adaptive sampling and (post-)deformation on a geomtric stream, and allows to perform interactive deformation on arbitrary large models. The complete idea is discussed in the full paper "SIMOD: Making Freeform Deformation Size-Insensitive", published in the proceedings of the Eurographics Symposium on Point-Based Graphics 2007 and available onlin...
Deformed aerogels in the superfluid 3He
Fomin, I. A.; Surovtsev, E. V.
2015-08-01
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 nondeformed state. Examples of originally isotropic silica aerogel and axially symmetric "nematically ordered" aerogel are considered. Values of phenomenological coefficients are estimated with the aid of a simple microscopic model. An example of a nonuniform deformation of nematically ordered aerogel is discussed.
Nanoscale near-surface deformation in polymer nanocomposites
Energy Technology Data Exchange (ETDEWEB)
Yuan, Q. [Center for Structural and Functional Materials, University of Louisiana at Lafayette, P.O. Box 44130, Lafayette, LA 70504-4130 (United States); Ramisetti, N. [Center for Structural and Functional Materials, University of Louisiana at Lafayette, P.O. Box 44130, Lafayette, LA 70504-4130 (United States); Department of Chemical Engineering, University of Louisiana at Lafayette, P.O. Box 44130, Lafayette, LA 70504-4130 (United States); Misra, R.D.K. [Center for Structural and Functional Materials, University of Louisiana at Lafayette, P.O. Box 44130, Lafayette, LA 70504-4130 (United States); Department of Chemical Engineering, University of Louisiana at Lafayette, P.O. Box 44130, Lafayette, LA 70504-4130 (United States)], E-mail: dmisra@louisiana.edu
2008-05-15
The objective of the study is to understand the nanoscale near-surface deformation response of two polymer nanocomposite systems with significant differences in ductility during nanoscratching with a Berkovich indenter using a load of 1 mN and a scratch velocity of 1 {mu}m s{sup -1}. An accompanying objective is to investigate the commonality in surface deformation behavior between nano- and microscale deformation to reinforce the underlying fundamental principles governing surface deformation. An understanding of surface deformation response is accomplished through determination of physical and mechanical properties, structural characterization and electron microscopy analysis of surface deformation tracks and residual plastically deformed structures. The study suggests for the first time that the understanding derived from microscale surface deformation studies can be extended to nanoscale surface deformation. The microscale response in a polypropylene-based system is characterized by periodic multiple ripple-type deformation tracks that form via a mechanism identical to the periodic single-ripple-type tracks during nanoscale deformation. Similarly, in a less ductile polyethylene-based system, the periodic parabolic tracks and ironing mode of deformation during microscale deformation tend to be significantly reduced in intensity, with ironing being the primary deformation mechanism at the nanoscale. The surface deformation topography suggests that both micro- and nanoscale response is material specific. Additionally, the study suggests that reinforcement of polymers with nanoclay is a viable route to significantly decrease the susceptibility of polymeric materials to micro- and nanoscale deformation and can be discussed in terms of physical and mechanical properties of materials notably percentage crystallinity and elastic recovery.
Thermal conductivity of deformed carbon nanotubes
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...
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.
International Nuclear Information System (INIS)
The database of the GAP site is under development. In order to meet the data needs of the different modelling teams working with groundwater flow modelling it has been decided to compile trial data sets comprising structural-hydraulic properties suitable for flow modelling on different scales. The properties provided in this report are based on data and groundwater flow modelling studies conducted for three sites located in the Fennoscandian Shield, two of which are studied by SKB, Forsmark and Laxemar, and one by Posiva, Olkiluoto. The provided hydraulic properties provided here are simplified to facilitate a readily usage together with the GAP Geomodel version 1
We propose to exploit the unique capability of ISOLDE to provide intense post-accelerated $^{144}$Ba ion beams from the REX facility to enable the Coulomb excitation of the first 3 $^{-}$ state in this nucleus. By measuring the $\\gamma$-ray yields of the E1 decay connecting the 3$^{-}$ and 2$^{+}$ states using the MINIBALL array, we can obtain the interesting transition matrix element. The result will give quantitative information about octupole correlations in this nucleus. We require 27 shifts to fulfil the aims of the experiment. Requested shifts:
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.
Scientific Electronic Library Online (English)
G. R. X., Souza; S. B., Gabriel; A. F., Ribeiro; L. H. de, Almeida.
Full Text Available A superliga de níquel X-750 pertence a classe das ligas níquel-cromo-alumínio-titânio e é indicada para aplicações em altas temperaturas e ambientes corrosivos. Entre outras aplicações é utilizada para a fabricação de molas helicoidais operando como componente estrutural de reatores nucleares. A pre [...] sença do titânio em teores da ordem de 2,5% em peso confere à liga elevada resistência mecânica pelo mecanismo de endurecimento por precipitação da fase coerente ?'. Por outro lado o controle das propriedades mecânicas finais é fortemente dependente do grau de encruamento prévio ao tratamento térmico de envelhecimento. Segundo a norma AMS 5698G, o fio da superliga X-750 a ser utilizado na fabricação de molas helicoidais deve ser submetido a um tratamento térmico de solubilização e em seguida deve ser reduzido a frio de aproximadamente 15% de sua área. Após a redução, a mola é conformada e submetida a um tratamento de precipitação e resfriada ao ar. No entanto, não se encontra na literatura cientifica dados suficientes para caracterizar as propriedades mecânicas, particularmente os níveis de resistência, em função dos mecanismos de endurecimento atuantes. O presente trabalho teve como objetivo estudar diferentes rotas de processamento para se obter fios da liga X-750 de forma a maximizar as propriedades para a aplicação na fabricação de molas helicoidais em função do grau de deformação do último passe de trefilação. As diferentes etapas de processamento foram caracterizadas por microscopia ótica e eletrônica de varredura e as propriedades mecânicas por ensaio de dureza Vickers e tração uniaxial. Observou-se, como esperado, que o ganho de resistência devido à deformação foi proporcional ao grau de deformação aplicado. Por outro lado, entretanto, o ganho de resistência devido ao tratamento térmico de envelhecimento é reduzida com o aumento do grau de deformação, ocasionando em uma tensão limite de escoamento cada vez mais dependente do grau de encruamento e, dessa forma, em prejuízo de tenacidade. Abstract in english The nickel base superalloy X-750 is a nickel-chromium-titanium-aluminum alloy that is suitable for high temperature applications and corrosive environments. Among others applications, it can be used in helical springs manufacturing acting as a structural component in nuclear reactors. The titanium p [...] resence at levels of about 2.5wt% gives the alloy high strength by precipitation of the coherent phase ?'. According to the standard AMS 5698G, the wire of X-750 alloy to be used in helical springs manufacturing must be subjected to a solution heat treatment and then be cold reduced by approximately 15% of its area. After the reduction, the spring is shaped as well as precipitation heat treated and air cooling. However, there is not enough data in the scientific literature to characterize the mechanical properties, particularly resistance levels as a function of these hardening mechanisms. This paper aimed to study different processing routes to obtain wires of X-750 alloy in order to maximize the properties for helical springs applications according to the last pass drawing deformation degree. The different processing steps were characterized by optical microscopy and scanning electron microscopy and mechanical properties by Vickers hardness and tensile. As expected, the resistance gain due to deformation was proportional to the deformation degree applied. On the other hand, however, the aging heat treatment contribution is reduced with the deformation degree increasing, resulting in a yield stress increasingly dependent on the hardening degree.
Haghshenas-Haghighi, M.; Motagh, M.; Heim, B.; Sachs, T.; Kohnert, K.; Streletskiy, D. A.
2014-12-01
In this study, we assess seasonal subsidence/heaving due to thawing/freezing of the permafrost in Barrow (71.3 N, 156.5 W) at the northernmost point of Alaska. The topographic relief in this area is low. Thick Permafrost underlies the entire area, with large ice volumes in its upper layer. With a large collection of field measurements during the past decades at the Barrow Environmental Observatory (BEO), it is an ideal site for permafrost investigation. There are long term systematic geocryological investigations within the Global Terrestrial Network (GTN-P) of the Circumpolar Active Layer Monitoring (CALM) programme. We use 28 TerraSAR-X images, acquired between December 2012 and December 2013 and analyze them using the Small BAseline Subset (SBAS) technique to extract time-series of ground surface deformation. We also analyze hyperspectral images acquired by the airborne AISA sensor over Barrow area, within the AIRMETH2013 programme, to assess physical characteristics such as vegetation biomass and density, surface moisture, and water bodies. Finally, we combine the information derived from both InSAR and hyperspectral analysis, with field measurements to investigate the link between physical characteristics of the permafrost and surface displacement.
International Nuclear Information System (INIS)
The waste packages, which Japan Atomic Energy Agency plans to dispose of, must be satisfied the technical standard specified by the Ordinance of Ministry of Economy, Trade and Industry. One of the technical standards is that the waste package must have enough strength to withstand the load when it is disposed of finally by burial method. Japan Atomic Energy Agency is required to prove the compliance of the waste package with the technical standard quantitatively because we shall obtain the confirmation of the regulatory authority. Accordingly the static load test was conducted to evaluate compressive strength and deformation performance of waste containers. The targets were 200 liter drum, concrete reinforced 200 liter drum, 200 liter drum containing cement solidified product and 1m3 cubic container which are expected to emplace into a concrete pit type disposal facility. Compression apparatuses which can imitate a loading condition in the facility were used. Based on the test result, 200 liter drum(M-class) has a minimum strength of 18kN and 1m3 cubic container has a maximum strength of 400kN. (author)
International Nuclear Information System (INIS)
One investigates into the effect of deformation of crystalline lattice of CaxSr1-xF2 and Sr1-xBaxF2 mixed crystals (0 ? x ? 1) on the parameters of magnetic interactions of [CuF8]6- and [AgF8]6- impurity Jahn-Teller complexes. One used EPR technique to carry out investigations within 4.2-250 K temperature range and at 9.3 and 37 GHz frequencies. One presents components of tensors of spin Hamiltonians of [AgF8]6- and [CuF8]6- complexes derived on the basis of analysis of angular dependence of position of resonance lines of EPR spectra. One evaluated the upper limits for energy of the Jahn-Teller interaction in silver trigonal complexes in CdF2, CaF2 and SrF2 crystals and copper orthorhombic complexes in CdF2 and CaF2. The lower limits are determined by values of spin-orbital bond energy for Ag2+ and Cu2+
Noncommutative deformations and flops
Donovan, Will; Wemyss, Michael
2013-01-01
We prove that the functor of noncommutative deformations of every flipping or flopping rational curve in a 3-fold is representable, and hence associate to every such curve a noncommutative deformation algebra. This new invariant extends and unifies known invariants for flopping curves in 3-folds, such as the width of Reid, and the bidegree of the normal bundle. It also applies in the settings of flips and singular schemes. We show that the noncommutative deformation algebra ...
Deformations of Quantum Field Theories on Curved Spacetimes
Morales, Eric Morfa
2012-01-01
The construction and analysis of deformations of quantum field theories by warped convolutions is extended to a class of globally hyperbolic spacetimes. First, we show that any four-dimensional spacetime which admits two commuting and spacelike Killing vector fields carries a family of wedge regions with causal properties analogous to the Minkowski space wedges. Deformations of quantum field theories on these spacetimes are carried out within the operator-algebraic framework - the emerging models share many structural properties with deformations of field theories on flat spacetime. In particular, deformed quantum fields are localized in the wedges of the considered spacetime. As a concrete example, the deformation of the free Dirac field is studied. Second, quantum field theories on de Sitter spacetime with global U(1) gauge symmetry are deformed using the joint action of the internal symmetry group and a one-parameter group of boosts. The resulting theories turn out to be wedge-local and non-isomorphic to t...
Hwang, J. K.; Hamilton, J. H.; Ramayya, A. V.; Luo, Y. X.
2013-06-01
High spin states of 134Sb, 134, 135Te, 135, 136I, 137Xe and 139Ba near 132Sn are reanalysed in order to search for octupole phonon vibrational states. New spins and parities are tentatively assigned to the 2203.9 keV state in 137Xe and the 1976.6 and 2091.7 keV states in 139Ba from the state energy plots of the N = 82 and 83 nuclei. High spin states of 134Sb, 134, 135Te, 135, 136I, 137Xe and 139Ba connected by E1, E3/M2 and E3 transitions are proposed, for the first time, as zero-, one- and two-phonon octupole vibrational (POV) states. One- and two-POV states in 134Sb and 135Te are built on a 7- (?g7/2?f7/2) state and a 19/2- (?f7/2???6_1^+) state, respectively. One-POV states built on the 19/2- (?f7/2???6_1^+) and the 21/2- (?h9/2???6_2^+) states coexist in 137Xe. Then, one- and two-POV states in 139Ba are built only on the 21/2- (?h9/2???6_2^+) state. One- and two-POV states in 134Te are built on the 6^+_2 state with some mixing with the 6^+_1 state.
Deformation of intermetallic compounds
International Nuclear Information System (INIS)
In this chapter attention is first focused on dislocations and planar faults in intermetallic compounds in order to understand their plastic behavior. Then the experimental and theoretical approaches to the study of attractive mechanical properties and interesting deformation characteristics are presented. Ductility improvement of several intermetallic compounds has been established through micro- and macro-alloying additions, grain refinement and microstructure control by thermo-mechanical processing. For example, it has been discovered that small additions of boron result in a more than 50% elongation of polycrystalline Ni3Al at room temperature due to the suppression of grain boundary embrittlement. Ductility and embrittlement will be discussed in Sec. 6.5. Some new compounds such as TiAl and Al3Ti are of great interest for automotive and aerospace applications because of their low density and superior strength-to-weight ratio. The aluminides and silicides of refractory metals such as Mo, Nb and W are also of interest in the development of new, extremely high-temperature materials of aircraft gas turbines and airframes operating around 1500degC. Finally, recent studies on such advanced intermetallics as high-temperature structural materials are presented. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Vasco, D.W.
2011-10-01
Using an asymptotic technique, valid when the medium properties are smoothly-varying, I derive a semi-analytic expression for the propagation velocity of a quasi-static disturbance traveling within a nonlinear-elastic porous medium. The phase, a function related to the propagation time, depends upon the properties of the medium, including the pressure-sensitivities of the medium parameters, and on pressure and displacement amplitude changes. Thus, the propagation velocity of a disturbance depends upon its amplitude, as might be expected for a nonlinear process. As a check, the expression for the phase function is evaluated for a poroelastic medium, when the material properties do not depend upon the fluid pressure. In that case, the travel time estimates agree with conventional analytic estimates, and with values calculated using a numerical simulator. For a medium with pressure-dependent permeability I find general agreement between the semi-analytic estimates and estimates from a numerical simulation. In this case the pressure amplitude changes are obtained from the numerical simulator.
Deformation retracts of Stein spaces
International Nuclear Information System (INIS)
If X is an n-dimensional Stein space, it was proved that X has the homotopy type of a CW-complex of dimension?n and in the algebraic case this was proved with the additional conclusion that the CW-complex is finite. In this paper the authors give an answer to the question if there exists a subset Q of X with the same topological properties as X, for instance Q is a strong deformation retract of X, and Q is a CW-complex of dimension?n. 15 refs
Dislocation Dynamics During Plastic Deformation
Messerschmidt, Ulrich
2010-01-01
The book gives an overview of the dynamic behavior of dislocations and its relation to plastic deformation. It introduces the general properties of dislocations and treats the dislocation dynamics in some detail. Finally, examples are described of the processes in different classes of materials, i.e. semiconductors, ceramics, metals, intermetallic materials, and quasicrystals. The processes are illustrated by many electron micrographs of dislocations under stress and by video clips taken during in situ straining experiments in a high-voltage electron microscope showing moving dislocations. Thus, the users of the book also obtain an immediate impression and understanding of dislocation dynamics.
Deformation mechanisms of naurally deformed rocksalt
Schléder, Zsolt
2006-01-01
Die vorliegende Doktorarbeit präsentiert zahlreiche Untersuchungen zu Deformations- und Rekristallisationsprozessen natürlich deformierter Salzgesteine. Zur Analyse wurden die in der Halit-Mikrotektonik üblichen Methoden angewandt: Durchlicht- und Auflichtmikroskopie von Gamma-bestrahlten Salzdünnschliffen sowie Orientierungsmessungen mit EBSD. Zur Untersuchung von unterschiedlichen tektonischen Szenarien wurden entsprechende Fallstudien gewählt: Schwach deformiertes geschichtetes Röt Steins...
Directory of Open Access Journals (Sweden)
B. Chatterjee
2011-12-01
Full Text Available The present study considers finite element based contact analysis of an elastic-plastic axisymmetric hemisphere using ANSYS to study the effect of material properties under full stick contact condition. Results are compared with previous elastic-plastic models for perfect slip and full stick contact conditions. It is found that materials with modulus of elasticity to yield strength (E/Y ratio less than and greater than 300 show strikingly different contact behavior. When E/Y ratio is less than 300, contact load increases with the increase in modulus of elasticity whereas in elastic-plastic range, contact load decreases with the increase in yield strength.
Leng, Zhe; Zhang, Jinghuai; Yin, Tingting; Zhang, Li; Guo, Xuying; Peng, Qiuming; Zhang, Milin; Wu, Ruizhi
2013-12-01
The microstructure and mechanical properties of as-extruded Mg-8Y-1Er-2Zn (wt%) alloy containing long period stacking ordered (LPSO) phase are comparatively investigated before and after corrosion in a simulated body fluid (SBF) at 37°C. The as-extruded alloy consists of a long strip-like 18R-LPSO phase and some fine lamellae grains formed by primary recrystallization during the extrusion process. The hydrogen evolution volume per day fluctuates between 0.21 and 0.32ml/cm(2) in the immersion test for 240h, and the corresponding corrosion rate is calculated as 0.568mm/y. The corrosion product is determined as Mg(OH)2, whilst a Ca(H2PO4)2 compound is also observed on the surface of the samples. The corrosion site preferentially occurs at the interface between LPSO phase and Mg matrix. Before immersing, the tensile yield strength (TYS), ultimate tensile strength (UTS) and elongation of the alloy are 275MPa, 359MPa, and 19%, respectively. More attractively, these mechanical properties can be maintained even after immersing in SBF for 240h (TYS, UTS and elongation are 216MPa, 286MPa and 6.8%, respectively) because of the existence of high anti-corrosion LPSO phase. PMID:24036280
Sonboli, Ali; Toroghinejad, Mohammad Reza; Edris, Hossein; Szpunar, Jerzy A.
2015-07-01
In the present work the influence of intermediate annealing and the strain path during a two-stage cold rolling on the microstructure and texture of a 1 wt% Si non-oriented electrical steel was investigated. Different processing conditions were tasted to develop favorable texture and better understand the relation between texture and important magnetic properties. The texture parameter (TP) was defined as "theta fiber/gamma fiber" ratio. The results showed that the samples with the highest TP have the lowest magnetic anisotropy. Also average magnetocrystalline energy was calculated and it was demonstrated that the lowest energy can be correlated with the highest "theta fiber/gamma fiber" ratio. Regardless of the condition of intermediate annealing process, the uni-directional rolling produced very similar texture parameter (~2). However, the cross rolled samples have very different texture parameters upon intermediate annealing. The cross rolled samples after intermediate annealing at 650 °C have the highest texture parameter (~3). The proposed thermo-mechanical processing allow diminishing gamma fiber which is deleterious for magnetic properties of non-oriented electrical steels.
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
Intermetallic alloys: Deformation, mechanical and fracture behaviour
International Nuclear Information System (INIS)
The state of the art in intermetallic alloys development with particular emphasis on deformation, mechanical and fracture behaviour is documented. This review paper is prepared to lay the ground stones for a future work on mechanical property characterization and fracture behaviour of intermetallic alloys at GKSS. (orig.)
Mechanical biocompatibility of highly deformable biomedical materials.
Mazza, Edoardo; Ehret, Alexander E
2015-08-01
Mismatch of mechanical properties between highly deformable biomedical materials and adjacent native tissue might lead to short and long term health impairment. The capability of implants to deform at the right level, i.e. similar to the macroscopic mechanical response of the surrounding biological materials, is often associated with dissimilar microstructural deformation mechanisms. This mismatch on smaller length scales might lead to micro-injuries, cell damage, inflammation, fibrosis or necrosis. Hence, the mechanical biocompatibility of soft implants depends not only on the properties and composition of the implant material, but also on its organization, distribution and motion at one or several length scales. The challenges related to the analysis and attainment of mechanical biocompatibility are illustrated with two examples: prosthetic meshes for hernia and pelvic repair and electrospun scaffolds for tissue engineering. For these material systems we describe existing methods for characterization and analysis of the non-linear response to uniaxial and multiaxial stress states, its time and history dependence, and the changes in deformation behavior associated with tissue in-growth and material resorption. We discuss the multi-scale deformation behavior of biomaterials and adjacent tissue, and indicate major interdisciplinary questions to be addressed in future research. PMID:25916818
Neves, J C S
2015-01-01
In this work, we have deformed regular black holes which possess a general mass term described by a function which generalizes the Bardeen and Hayward mass terms. Using linear constraints in the energy-momentum tensor, the solutions are either regular or singular. That is, with this approach, it is possible to generate singular black holes from regular black holes and vice versa. Moreover, contrary to the Bardeen and Hayward regular solutions, the regular deformed metrics may violate the weak energy condition despite the presence of the spherical symmetry. Some comments on accretion of deformed black holes in cosmological scenarios are made.
The eigenstates of q-deformed creation operator a+
International Nuclear Information System (INIS)
In this paper, we construct the eigenstate of q-deformed creation operator a+ by using the contour integral representation of ? function. Some of its properties and applications are presented. (author). 6 refs
International Nuclear Information System (INIS)
A property of Quantum Chromodynamics (QCD) which should be included into effective models describing QCD at low energies is chiral symmetry. It is conserved if one assumes that the quark masses are zero. This symmetry is spontaneously broken, which leads to constituent quark and as the Goldstone Boson one obtains the pion and its chiral partner, the ? meson. We use the linear ? model which has, compared to the nonlinear one, the advantage that one treats pions and ? mesons not only on the chiral cycle, but allows also fluctuations around it. The scale of this fluctuations is the ? meson mass. If one eliminates gluons in second order, one obtains 'Tuebingen chiral quark model' with effective gluon exchange between the quarks and with pions and ? mesons. A confinement potential is added. With this model we describe the photo and electro-excitation of the nucleon into the delta resonance and the decay of this resonance into a nucleon and a pion. The angular distribution gives information about the C2/E2 admixture into the M1 transition from the nucleon to the delta resonance. The quadrupole contributions of this transition has been described in the past by d state admixture due to tensor forces from the gluon and the pion exchange. This yields values which are more then a factor 10 too small compared with recent data for the C2/E2 Sachs transition form factor. We show that meson and gluon pair exchange current can explain the data without the need of a large nucleon or delta deformation. The same model is than used to describe the nucleon-nucleon phase shift. An essential ingredient for the good agreement is to include to all orders couplings to ? channels. The 1S0 phase shift can only be described in agreement with the data if the coupling to the 5D0 nucleon delta channel is included. (author)
Impact between deformable bodies
International Nuclear Information System (INIS)
The bodies are represented by constant strain finite elements so that the element internal forces can most easily be calculated, especially after yielding has taken place when the stress and strain increments are related in accordance with the Prandtl-Reuss theory. In the case of axisymmetrical problems triangular axisymmetrical elements are used whose properties are approximately calculated by sampling at the centroid of the cross-section. The external applied forces arise from the impact and contact forces at the interfaces, and the inertia forces are obtained from lumped mass matrices. The equation of motion is solved by a central difference explicit scheme in small incremental time steps. This enables the stress propagation as well as the history of plastic deformation in the bodies to be traced throughout the duration of impact. The material law is idealised to be piecewise linear, with an initial elastic portion followed by one linear hardening segment. Perfect plasticity (zero hardening) can also be allowed. A simple procedure deals with the case of loading from an elastic initial state to a final plastic state in one time step. The program has been applied to the investigation of a number of axisymmetrical problems. The three dimensional version of the program is now being coded. Examples: impact of a falling fuel stringer in a storage tube; impact of a cylinder on a rigid boundary; supported circular plate loaded by uniformly distributed impulses; impact of aniformly distributed impulses; impact of a non-return valve in a pipe rupture; impact of a cylindrical fuel-waste flask; impact of a conical missile on a rigid surface. (orig./HP)
International Nuclear Information System (INIS)
A study is made into the influence of two-stage hot deformation by pressure first at temperatures above and then below eutectoid temperature (te ? 1125 deg C) with subsequent rolling below the temperature of eutectoid transformation on evolution of microstructure and texture in a cast intermetallic alloy of Ti-45.2Al-3.5(Nb,Cr,B). This treatment results in development of homogeneous fine-grained microstructure in the sheet due to recrystallization and formation of globular particles. Mechanical tensile tests of specimens cut out along and crosswise the rolling direction show a high ductility of sheet material in a temperature range of 900-1100 deg C, at temperatures of 1000-1100 deg C superplastic properties of the sheet appear to be isotropic. On this basis a new approach to the selection of the alloy and the working of ?-TiAl + ?2-Ti3Al base intermetallic alloys is suggested, which includes the use of the alloys completely solidifying with ?-phase formation, two-stage working first in (? + ?)- and then in (?2 + ?) phase fields with the most efficient structural refinement in the casting, resulting in the possibility of rolling below the eutectoid temperature
Deformations of quantum field theories on curved spacetimes
International Nuclear Information System (INIS)
The construction and analysis of deformations of quantum field theories by warped convolutions is extended to a class of globally hyperbolic spacetimes. First, we show that any four-dimensional spacetime which admits two commuting and spacelike Killing vector fields carries a family of wedge regions with causal properties analogous to the Minkowski space wedges. Deformations of quantum field theories on these spacetimes are carried out within the operator-algebraic framework - the emerging models share many structural properties with deformations of field theories on flat spacetime. In particular, deformed quantum fields are localized in the wedges of the considered spacetime. As a concrete example, the deformation of the free Dirac field is studied. Second, quantum field theories on de Sitter spacetime with global U(1) gauge symmetry are deformed using the joint action of the internal symmetry group and a one-parameter group of boosts. The resulting theories turn out to be wedge-local and non-isomorphic to the initial one for a class of theories, including the free charged Dirac field. The properties of deformed models coming from inclusions of CAR-algebras are studied in detail. Third, the deformation of the scalar free field in the Araki-Wood representation on Minkowski spacetime is discussed as a motivating example. (author)
Universal deformation formulas.
Czech Academy of Sciences Publication Activity Database
Remm, E.; Markl, Martin
2015-01-01
Ro?. 43, ?. 11 (2015), s. 4711-4734. ISSN 0092-7872 Institutional support: RVO:67985840 Keywords : algebra * deformation * twisting Impact factor: 0.388, year: 2014 http://www.tandfonline.com/doi/abs/10.1080/00927872.2014.949729
Quantum deformed magnon kinematics
International Nuclear Information System (INIS)
The dispersion relation for planar N = 4 supersymmetric Yang-Mills is identified with the Casimir of a quantum deformed two-dimensional kinematical symmetry, Eq(1, 1). The quantum deformed symmetry algebra is generated by the momentum, energy and boost, with deformation parameter q e2?i/?. Representing the boost as the infinitesimal generator for translations on the rapidity space leads to an elliptic uniformization with crossing transformations implemented through translations by the elliptic half-periods. This quantum deformed algebra can be interpreted as the kinematical symmetry of a discrete integrable model with lattice spacing given by the BMN length a = 2?/(?)1/2. The interpretation of the boost generator as the corner transfer matrix is briefly discussed
Extremely deformable structures
2015-01-01
Recently, a new research stimulus has derived from the observation that soft structures, such as biological systems, but also rubber and gel, may work in a post critical regime, where elastic elements are subject to extreme deformations, though still exhibiting excellent mechanical performances. This is the realm of ‘extreme mechanics’, to which this book is addressed. The possibility of exploiting highly deformable structures opens new and unexpected technological possibilities. In particular, the challenge is the design of deformable and bi-stable mechanisms which can reach superior mechanical performances and can have a strong impact on several high-tech applications, including stretchable electronics, nanotube serpentines, deployable structures for aerospace engineering, cable deployment in the ocean, but also sensors and flexible actuators and vibration absorbers. Readers are introduced to a variety of interrelated topics involving the mechanics of extremely deformable structures, with emphasis on ...
Directory of Open Access Journals (Sweden)
W. Ozgowicz
2009-09-01
Full Text Available 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 out on a light microscope and the fractographic investigation of fracture on an electron scanning microscope.Findings: The mechanical properties of alloys as well as the range of occurrence of the Portevin - Le Chatelier (PLC phenomenon was determined on the basis of F-?L curves formed by tensile tests; however the character of fracture during the break of the samples was defined on the basis of fractographic investigations.Research limitations/implications:Practical implications: In result of tensile tests of copper alloys it has been found that the PLC effect occurs in both alloys in the temperature range of 150-350°C. However, the ductility minimum temperature of the alloys equals about 500°C. At the temperature of stretching of about 450°C the investigated copper alloys show maximum strength values.Originality/value: The type of ”teething” on the load - displacement curves was defined, according to the classification received in literature. The dependence ?kr = f(t was marked too.
Quadrupole deformation in -hypernuclei
Bhowmick, Bipasha; Bhattacharyya, Abhijit; Gangopadhyay, G.
2014-08-01
Shapes of light normal nuclei and -hypernuclei are investigated using the relativistic mean-field approach. The FSUGold parametrization is used for this purpose. The addition of a is found to change the shape of the energy surface towards positive deformation, i.e., prolate shape. The deformation in a -hypernucleus, when the hyperon is in the first excited state, is also discussed. The effect of the inclusion of the hyperon on the nuclear radius is generally small with one exception.
Quadrupole deformation in ? -hypernuclei
Energy Technology Data Exchange (ETDEWEB)
Bhowmick, Bipasha; Bhattacharyya, Abhijit; Gangopadhyay, G. [University of Calcutta, Department of Physics, Kolkata (India)
2014-08-15
Shapes of light normal nuclei and ? -hypernuclei are investigated using the relativistic mean-field approach. The FSUGold parametrization is used for this purpose. The addition of a ? is found to change the shape of the energy surface towards positive deformation, i.e., prolate shape. The deformation in a ? -hypernucleus, when the hyperon is in the first excited state, is also discussed. The effect of the inclusion of the hyperon on the nuclear radius is generally small with one exception. (orig.)
Arratia, Oscar; Martin, Miguel A; Olmo, Mariano A.
1998-01-01
We review several procedures of quantization formulated in the framework of (classical) phase space M. These quantization methods consider Quantum Mechanics as a "deformation" of Classical Mechanics by means of the "transformation" of the commutative algebra of smooth functions on M in a new non-commutative algebra. These ideas lead in a natural way to Quantum Groups as deformation (or quantization, in a broad sense) of Poisson-Lie groups, which is also analysed here.
Deformation of Wrinkled Graphene
Li, Zheling; Kinloch, Ian A.; Young, Robert J; Novoselov, Kostya S.; Anagnostopoulos, George; Parthenios, John; Galiotis, Costas; Papagelis, Konstantinos; Lu, Ching-Yu; Britnell, Liam
2015-01-01
The deformation of monolayer graphene, produced by chemical vapor deposition (CVD), on a polyester film substrate has been investigated through the use of Raman spectroscopy. It has been found that the microstructure of the CVD graphene consists of a hexagonal array of islands of flat monolayer graphene separated by wrinkled material. During deformation, it was found that the rate of shift of the Raman 2D band wavenumber per unit strain was less than 25% of that of flat flak...
Deformations of algebroid stacks
DEFF Research Database (Denmark)
Bressler, Paul; Gorokhovsky, Alexander
2011-01-01
In this paper we consider deformations of an algebroid stack on an étale groupoid. We construct a differential graded Lie algebra (DGLA) which controls this deformation theory. In the case when the algebroid is a twisted form of functions we show that this DGLA is quasiisomorphic to the twist of the DGLA of Hochschild cochains on the algebra of functions on the groupoid by the characteristic class of the corresponding gerbe.
Stevens, Jan
2003-01-01
These notes deal with deformation theory of complex analytic singularities and related objects. The first part treats general theory. The central notion is that of versal deformation in several variants. The theory is developed both in an abstract way and in a concrete way suitable for computations. The second part deals with more specific problems, specially on curves and surfaces. Smoothings of singularities are the main concern. Examples are spread throughout the text.
Lorentz invariant deformations of momentum space
Astuti, Valerio
2015-01-01
In relative locality theories the geometric properties of phase space depart from the standard ones given by the fact that spaces of momenta are linear fibers over a spacetime base manifold. In particular here it is assumed that the momentum space is non linear and can therefore carry non trivial metric and composition law. We classify to second order all possible such deformations that preserve Lorentz invariance. We show that such deformations still exists after quotienting out by diffeomorphisms only if the non linear addition is non associative.
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.
International Nuclear Information System (INIS)
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 Xe26+, Cs27+, and Ba28+. Of particular interest is the lowest excited level, 3d94s 3D3, 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
Directory of Open Access Journals (Sweden)
Trémolières P.
2006-11-01
Full Text Available Cet article présente les principaux résultats d'une étude menée en commun par l'Institut Français du Pétrole (IFP et la Société Nationale Elf Aquitaine (Production (SNEA (P, étude qui avait pour but de rechercher l'influence des contraintes tectoniques sur les propriétés pétrophysiques matricielles des réservoirs calcaires. Ces travaux, ayant porté principalement surle Burdigalien des Alpilles (Provence et accessoirement sur le Turonien de Mareuil (Aquitaine et la « Scaglia bianca » du Monte Conero (Ancàne-Itatie, ont permis de mettre en évidence - des variations importantes de la porosité et de la perméabilité en fonction de la position structurale du matériau et, à plus petite échelle, de la courbure des couches; - un double processus de la réduction des porosité et perméabilité : soit par tassement mécanique, soit par cristallisation dans les pores d'une calcite provenant probablement d'une dissolution le long de joints stylolithiques d'origine tectonique. On montre enfin qu'en certaines zones particulières (dans les périclinaux ou à l'aplomb d'accidents profonds jouant en faille inverse les effets des contraintes tectoniques sur les qualités matricielles peuvent être très importants et survenir avant la structuration des couches par plissement. This article describes the main results of a joint Institut Français du Pétrole (IFP-Société Nationale Elf Aquitaine (Production (SNEA (P research project on the influence of tectonic stresses on thé petrophysical matrix properties of limestone reservoirs. Research mainly concentrated on the Burdigalien from the Alpilles mountains in ihe Provence région and accessorily on the Turonian from Mareuil in the Aquitaine region and Scaglia Bianca from Monte Conero in Anconia, Italy. The following findings were made: - considerable variations in porosity and permeability can be found, depending on the structural position of the material and, on a smaller scale, on the curve of the loyers; - there is a double porosity and permeability réduction process, either by mechanical settling or by thé crystallization in thé pores of a calcite probably coming from a dissolution occurring along stylolitic joints of tectonic origin. It is also shown that in some specific zones (in periclines or directly underneath deep accidents in thé form of thrust faults thé effects of tectonic stresses on matrix qualities may be very great and may occur prior to the folding structuration of the loyers.
Molybdenum recrystallization deformed by forging and hydropressing
International Nuclear Information System (INIS)
Certain pecularities are studied and recrystallization diagrams of MChVP mark 1 type molybdenum, processed under commercial conditions according to two deformation regimes-forging and hydropressing are constructed. It is shown that in molybdenum subjected both to forging an hydropressing a relatively fine grain is contained under the deformation degrees exceeding 50% and annealings of up to 1600-1700 deg C. Annealing at higher temperatures leads to producing a large-grain structure under all deformation degrees. Hydropressing provides for a more homogeneous structure (as compared to forging) in recrystallized molybdenum, as well as for improvement of strength properties within Tann=800-1500 deg C interval by 20% and elastic properies (Tann=1400-1500 deg C) by 30-50%
New deformations of Convolution algebras and Fourier algebras on locally compact groups
Lee, Hun Hee; Youn, SangGyun
2015-01-01
In this paper we introduce a new way of deforming convolution algebras and Fourier algebras on locally compact groups. We demonstrate that this new deformation allows us to reveal some informations of the underlying groups by examinining Banach algebra properties of deformed algebras. More precisely, we focus on representability as an operator algebra of deformed convolution algebras on compact connected Lie groups with connection to the real dimension of the underlying grou...
Deformation in nanocrystalline metals
Directory of Open Access Journals (Sweden)
Helena Van Swygenhoven
2006-05-01
Full Text Available It is now possible to synthesize polycrystalline metals made up of grains that average less than 100 nm in size. Such nanocrystalline metals contain a significant volume fraction of interfacial regions separated by nearly perfect crystals. The small sizes involved limit the conventional operation of dislocation sources and thus a fundamental question arises: how do these materials deform plastically? We review the current views on deformation mechanisms in nanocrystalline, face-centered cubic metals based on insights gained by atomistic computer simulations. These insights are discussed with reference to recent striking experimental observations that can be compared with predictions made by the simulations.
Deforming geometric transitions
Rossi, Michele
2015-04-01
After a quick review of the wild structure of the complex moduli space of Calabi-Yau 3-folds and the role of geometric transitions in this context (the Calabi-Yau web) the concept of deformation equivalence for geometric transitions is introduced to understand the arrows of the Gross-Reid Calabi-Yau web as deformation-equivalence classes of geometric transitions. Then the focus will be on some results and suitable examples to understand under which conditions it is possible to get simple geometric transitions, which are almost the only well-understood geometric transitions both in mathematics and in physics.
International Nuclear Information System (INIS)
The IS475 collaboration conducted Coulomb-excitation experiments with postaccelerated radioactive 220Rn and 224Ra beams at the REX-ISOLDE facility. The beam particles (Ebeam ? 2.83 MeV/u) were Coulomb excited using 60Ni, 114Cd, and 120Sn scattering targets. De-excitation ?-rays were detected employing the Miniball array and scattered particles were detected in a silicon detector. Exploiting the Coulomb-excitation code GOSIA for each nucleus several matrix elements could be obtained from the measured ?-ray yields. The extracted (3?||Ê3||0+) matrix element allows for the conclusion that, while 220Rn represents an octupole vibrational system, 224Ra has already substantial octupole correlations in its ground state. An observation that has implications for the search of CP-violating Schiff moments in the atomic systems of the adjacent odd-mass nuclei.
Deformed Covariant Quantum Phase Spaces as Hopf Algebroids
Lukierski, Jerzy
2015-01-01
We consider the general D=4 (10+10)-dimensional kappa-deformed quantum phase space as given by Heisenberg double \\mathcal{H} of D=4 kappa-deformed Poincare-Hopf algebra H. The standard (4+4) -dimensional kappa - deformed covariant quantum phase space spanned by kappa - deformed Minkowski coordinates and commuting momenta generators ({x}_{\\mu },{p}_{\\mu }) is obtained as the subalgebra of \\mathcal{H}. We study further the property that Heisenberg double defines particular quantum spaces with Hopf algebroid structure. We calculate by using purely algebraic methods the explicite Hopf algebroid structure of standard kappa - deformed quantum covariant phase space in Majid-Ruegg bicrossproduct basis. The coproducts for Hopf algebroids are not unique, determined modulo the coproduct gauge freedom. Finally we consider the interpretation of the algebraic description of quantum phase spaces as Hopf bialgebroids.
Unimorph-type deformable mirror for cryogenic telescopes
Reinlein, Claudia; Goy, Matthias; Lange, Nicolas; Kinast, Jan
2014-07-01
Deformable mirrors can be used in cryogenic instruments to compensate for temperature-induced deformations. A unimorph-type deformable mirror consists of a mirror substrate and a piezoelectric layer bonded on substrates rear surface. A challenge in the design of the deformable mirror is the lack of knowledge about material properties. Therefore, we measured the coefficient of thermal expansion (CTE) of the substrate material TiAl6V4 between 295 K and 86 K. The manufactured mirror is characterized by an adaptive optical measurement setup in front of a test cryostat. The measured mirror deformations are feedback into a finite element model to calculate the CTE of the piezoelectric layer. We compare our obtained results to other published CTE-values for the piezoelectric material PIC151.
Deformable Simplicial Complexes
DEFF Research Database (Denmark)
Misztal, Marek Krzysztof
2010-01-01
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 interface (curve in 2D; surface in 3D) is represented explicitly as a piecewise linear curve or surface. However, the domain is also subject to discretization: triangulation in 2D; tetrahedralization in 3D. This way, the interface can be alternatively represented as a set of edges/triangles separating 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 demonstrate those strengths in several applications. In particular, a novel, DSC-based fluid dynamics solver has been developed during the PhD project. A special feature of this solver is that due to the fact that DSC maintains an explicit interface representation, surface tension is more easily dealt with. One particular advantage of DSC is the fact that as an alternative to topology adaptivity, topology control is also possible. This is exploited in the construction of cut loci on tori where a front expands from a single point on a torus and stops when it self-intersects.
Deformation Theory ( Lecture Notes ).
Czech Academy of Sciences Publication Activity Database
Doubek, M.; Markl, Martin; Zima, P.
2007-01-01
Ro?. 43, ?. 5 (2007), s. 333-371. ISSN 0044-8753. [Winter School Geometry and Physics/27./. Srní, 13.01.2007-20.01.2007] R&D Projects: GA ?R GA201/05/2117 Institutional research plan: CEZ:AV0Z10190503 Keywords : deformation * Mauerer-Cartan equation * strongly homotopy Lie algebra Subject RIV: BA - General Mathematics
Optically Driven Deformable Mirrors
Hemmati, Hamid
2006-01-01
Optically driven deformable mirrors may eventually supplant electrically driven deformable mirrors in some adaptive-optics and active-optics applications. Traditionally, the mirror facets in electrically driven deformable mirrors are actuated, variously, by means of piezoelectric, electrostrictive, microelectromechanical, liquid-crystal, or thermal devices. At least one such device must be dedicated to each facet, and there must be at least one wire carrying a control or drive signal to the device. If a deformable mirror comprises many (e.g., thousands) of facets, then wiring becomes a major problem for design, and the problem is compounded in cases of piezoelectric or other actuators for which high drive voltages are required. In contrast, in optically driven mirrors, the wiring problem is eliminated. The basic principle of actuation of an optically driven deformable mirror is to use a laser beam to actuate a material. For example, a laser beam can be used to heat a material to make the material thermally expand to displace a mirror facet. In an experiment to demonstrate this principle, the actuator was a Golay cell having a diameter of approximately equal to 6 mm and a length of approximately equal to 10 mm. The beam from a laser diode was aimed at an absorber in the cell, thereby heating the gas in the cell. A mirror mounted on a 12.5-micron-thick polyethylene terephthalate diaphragm at one end of the cell became displaced as the gas expanded against the diaphragm. In one representative pair of experiments at a laser beam power of 0.23 W, the beam was mechanically chopped at frequencies of 1 and 5 Hz. The mirror exhibited corresponding oscillating displacements having amplitudes of 373 and 83 micron, respectively
Statics of polymer droplets on deformable surfaces
Léonforte, Fabien; Müller, Marcus
2011-01-01
The equilibrium properties of polymer droplets on a soft deformable surface are investigated by molecular dynamics simulations of a bead-spring model. The surface consists of a polymer brush with irreversibly end-tethered linear homopolymer chains onto a flat solid substrate. We tune the softness of the surface by varying the grafting density. Droplets are comprised of bead-spring polymers of various chain lengths. First, both systems, brush and polymer liquid, are studied i...
Rapid collision detection for deformable objects using inclusion-fields applied to cloth simulation
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Asma A. ElBadrawy
2012-07-01
Full Text Available We introduce an inclusion-field technique for fast detection of collisions between a highly deformable object and another object with limited deformations. We mainly target the cloth simulation application where cloth (highly deformable collides with deforming skin of a moving human model (has limited deformation as skin stretches and compacts within finite spacial and temporal limits specified by the bending angle and speed. Our technique intermixes concepts from space voxelization and distance fields to make use of the limited deformation nature of human skin. The technique works by discretizing the space containing the object into cells, and giving each cell an inclusion property. This property specifies whether this cell lies inside, outside, or on the surface of the deforming object. As the object deforms, the cells’ inclusion properties are updated to maintain the correctness of the collision detection process. We tested our technique on a generally deforming Bezier surface, and on cloth simulation to detect collisions between cloth and several articulated and deforming human body parts. Results showed that the inclusion field allows real-time collision detection between cloth and limited deformable objects on a standard PC. The technique is simple and easy to implement.
International Nuclear Information System (INIS)
The q-deformed kink of the ??4 -model is obtained via the normalisable ground state eigenfunction of a fluctuation operator associated with the q-deformed hyperbolic functions. The kink mass, the bosonic zero-mode and the q-deformed potential in 1+1 dimensions are found. (author)
Deformed exterior algebra, quons and their coherent states
International Nuclear Information System (INIS)
We review the notion of the deformation of the exterior wedge product. This allows us to construct the deformation of the algebra of exterior forms over a vector space and also over an arbitrary manifold. We relate this approach to the generalized statistics and we study quons, as a particular case of these generalized statistics. We also give their statistical properties. A large part of the work is devoted to the problem of constructing coherent states for the deformed oscillators. We give a review of all the approaches existing in the literature concerning this point and enforce it with many examples. (author)
Deformation inequivalent complex conjugated complex structures and applications
Kharlamov, V M; Kulikov, Vik.
2001-01-01
Here, we resume and broaden the results concerned which appeared in math.AG/0101098 and math.AG/0104021. We start from summing up our example of a complex algebraic surface which is not deformation equivalent to its complex conjugate and which, moreover, has no homeomorphisms reversing the canonical class. Then, we construct several series of higher dimensional compact complex manifolds having the same property. We end with discussing applications to the Dif=Def problems, to the existence of diffeomorphic plane cuspidal curves non equivalent under equisingular deformations and to the existence of (deformation) non equivalent symplectic structures with opposite canonical classes.
On a deformation of the nonlinear Schr\\"odinger equation
Arnaudon, Alexis
2015-01-01
We study a deformation of the nonlinear Schr\\"odinger equation recently derived in Arnaudon 2015. This equation has been derived in the context of deformation of hierarchies of integrable systems and led to known integrable equations such that the Camassa-Holm equation. Although this new equation does not seem to be completely integrable, it contains solitonic solutions with interesting properties. We will first focus on standing wave solutions, which can be smooth or peaked...
Austenite-martensite transformation in ADI by plastic deformation
International Nuclear Information System (INIS)
In this article, retained austenite-martensite transformation occurred after plastic deformation and parameters that affect martensitic transformation in ADI is observed. Beside the technical and commercial advantages of ADI, martensitic transformation provides lower production costs and superior mechanical properties such as hardness and wearing resistance. In order to study this phenomenon, austempered GGG60 specimens are subjected to a fatigue test that causes plastic deformation. Afterward the specimens are investigated with metallography, mechanical testing and x-ray diffraction techniques. (Original)
Deformation and shape of flexible, microscale helices in viscous flow
Pham, Jonathan T.; Morozov, Alexander; Crosby, Alfred J.; Lindner, Anke; Roure, Olivia du
2015-01-01
We examine experimentally the deformation of flexible, microscale helical ribbons with nanoscale thickness subject to viscous flow in a microfluidic channel. Two aspects of flexible microhelices are quantified: the overall shape of the helix and the viscous frictional properties. The frictional coefficients determined by our experiments are consistent with calculated values in the context of resistive force theory. Deformation of helices by viscous flow is well-described by ...
Deformed supersymmetric mechanics
International Nuclear Information System (INIS)
Motivated by a recent interest in curved rigid supersymmetries, we construct a new type of N = 4, d = 1 supersymmetric systems by employing superfields defined on the cosets of the supergroup SU(2|1). The relevant worldline supersymmetry is a deformation of the standard N = 4, d = 1 supersymmetry by a mass parameter m. As instructive examples we consider at the classical and quantum levels the models associated with the supermultiplets (1,4,3) and (2,4,2) and find out interesting interrelations with some previous works on nonstandard d = 1 supersymmetry. In particular, the d = 1 systems with 'weak supersymmetry' are naturally reproduced within our SU(2|1) superfield approach as a subclass of the (1,4,3) models. A generalization to the N = 8, d = 1 case implies the supergroup SU(2|2) as a candidate deformed worldline supersymmetry
Deformed hyperbolic black holes
Chen, Yu; Teo, Edward
2015-01-01
Black holes with planar or hyperbolic horizon topology are known to exist in AdS space, alongside the usual ones with spherical topology. In this paper, we consider a one-parameter generalisation of these black holes that is contained in the AdS C-metric. In terms of the domain-structure analysis recently developed for such solutions, these black holes have a domain in the shape of a triangle. It is shown that the horizons of these black holes are deformed hyperbolic spaces, with the new parameter controlling the amount of deformation. The space-times are static and completely regular outside the horizons. We argue that these black holes are hyperbolic analogues of the "slowly accelerating" spherical black holes known to exist in AdS space.
Deformed hyperbolic black holes
Chen, Yu; Lim, Yen-Kheng; Teo, Edward
2015-08-01
Black holes with planar or hyperbolic horizons are known to exist in anti-de Sitter (AdS) space, alongside the usual ones with spherical horizons. In this paper, we consider a one-parameter generalization of these black holes that is contained in the AdS C-metric. In terms of the domain-structure analysis recently developed for such solutions, these black holes have a domain in the shape of a triangle. It is shown that the horizons of these black holes are deformed hyperbolic spaces, with the new parameter controlling the amount of deformation. The space-times are static and completely regular outside the horizons. We argue that these black holes are hyperbolic analogues of the "slowly accelerating" spherical black holes known to exist in AdS space.
Unifying derived deformation theories
Pridham, J. P.
2007-01-01
We develop a framework for derived deformation theory, valid in all characteristics. This gives a model category reconciling local and global approaches to derived moduli theory. In characteristic 0, we use this to show that the homotopy categories of DGLAs and SHLAs (L infinity algebras) considered by Kontsevich, Hinich and Manetti are equivalent, and are compatible with the derived stacks of Toen--Vezzosi and Lurie. Another application is that the cohomology groups associa...
Deformations of fractured rock
International Nuclear Information System (INIS)
Results of the DBM and FEM analysis in this study indicate that a suitable rock mass for repository of radioactive waste should be moderately jointed (about 1 joint/m2) and surrounded by shear zones of the first order. This allowes for a gentle and flexible deformation under tectonic stresses and prevent the development of large cross-cutting failures in the repository area. (author)
Energy Technology Data Exchange (ETDEWEB)
Winn, E.J.; Chen, I.-W. [Pennsylvania Univ., Philadelphia, PA (United States). Dept. of Materials Science and Engineering
2000-07-01
The inherent instability, under deformation, of the interface between two materials with dissimilar flow stresses is exploited in the production of composites with structures ranging from laminar to wood-like in texture. Conventional tape-casting is used to give materials with a flow stress controlled only by the binder/plasticiser ratio and the temperature. Repeated deformation of layered materials, by folding and warm-pressing, causes the harder phase to break up into discrete, elongated regions. Composites with a dense ZrO{sub 2} matrix and porous Al{sub 2}O{sub 3} inter layers exhibited graceful failure and crack deflection. (orig.)
Deformation of wrinkled graphene.
Li, Zheling; Kinloch, Ian A; Young, Robert J; Novoselov, Kostya S; Anagnostopoulos, George; Parthenios, John; Galiotis, Costas; Papagelis, Konstantinos; Lu, Ching-Yu; Britnell, Liam
2015-04-28
The deformation of monolayer graphene, produced by chemical vapor deposition (CVD), on a polyester film substrate has been investigated through the use of Raman spectroscopy. It has been found that the microstructure of the CVD graphene consists of a hexagonal array of islands of flat monolayer graphene separated by wrinkled material. During deformation, it was found that the rate of shift of the Raman 2D band wavenumber per unit strain was less than 25% of that of flat flakes of mechanically exfoliated graphene, whereas the rate of band broadening per unit strain was about 75% of that of the exfoliated material. This unusual deformation behavior has been modeled in terms of mechanically isolated graphene islands separated by the graphene wrinkles, with the strain distribution in each graphene island determined using shear lag analysis. The effect of the size and position of the Raman laser beam spot has also been incorporated in the model. The predictions fit well with the behavior observed experimentally for the Raman band shifts and broadening of the wrinkled CVD graphene. The effect of wrinkles upon the efficiency of graphene to reinforce nanocomposites is also discussed. PMID:25765609
Supertransvectants, cohomology, and deformations
Ben Fraj, Nizar; Laraiedh, Ismail; Omri, Salem
2013-02-01
Over the (1, N)-dimensional real superspace, N = 2, 3, we classify {osp}(N|2)-invariant binary differential operators acting on the superspaces of weighted densities, where {osp}(N|2) is the orthosymplectic Lie superalgebra. This result allows us to compute the first differential {osp}(N|2)-relative cohomology of the Lie superalgebra K(N) of contact vector fields with coefficients in the superspace of linear differential operators acting on the superspaces of weighted densities. We classify generic formal {osp}(3|2)-trivial deformations of the K(3)-module structure on the superspaces of symbols of differential operators. We prove that any generic formal {osp}(3|2)-trivial deformation of this K(3)-module is equivalent to its infinitesimal part. This work is the simplest generalization of a result by the first author et al. [Basdouri, I., Ben Ammar, M., Ben Fraj, N., Boujelbene, M., and Kammoun, K., "Cohomology of the Lie superalgebra of contact vector fields on {K}^{1|1} and deformations of the superspace of symbols," J. Nonlinear Math. Phys. 16, 373 (2009), 10.1142/S1402925109000431].
Layered Structures in Deformed Metals and Alloys
DEFF Research Database (Denmark)
Hansen, Niels; Zhang, Xiaodan
2014-01-01
Layered structures characterize metals and alloys deformed to high strain. The morphology is typical lamellar or fibrous and the interlamellar spacing can span several length scales down to the nanometer dimension. The layered structures can be observed in bulk or in surface regions, which is shown by the way of examples of different processing routes: friction, wire drawing, shot peening, high pressure torsion and rolling. The interlamellar spacing reaches from 5-10 nanometers to about one micrometer and the analysis will cover structural evolution, strengthening parameters and strength-structure relationships. Finally, the results will be discussed based on universal principles for the evolution of microstructure and properties during plastic deformation of metals and alloys from low to high strain.
Marginally Deformed Starobinsky Gravity
DEFF Research Database (Denmark)
Codello, A.; Joergensen, J.
2015-01-01
We show that quantum-induced marginal deformations of the Starobinsky gravitational action of the form $R^{2(1 -\\alpha)}$, with $R$ the Ricci scalar and $\\alpha$ a positive parameter, smaller than one half, can account for the recent experimental observations by BICEP2 of primordial tensor modes. We also suggest natural microscopic (non) gravitational sources of these corrections and demonstrate that they lead generally to a nonzero and positive $\\alpha$. Furthermore we argue, that within this framework, the tensor modes probe theories of grand unification with a large scalar field content.
Joining by plastic deformation
DEFF Research Database (Denmark)
Mori, Ken-ichiro; Bay, Niels
2013-01-01
As the scale and complexity of products such as aircraft and cars increase, demand for new functional processes to join mechanical parts grows. The use of plastic deformation for joining parts potentially offers improved accuracy, reliability and environmental safety as well as creating opportunities to design new products through joining dissimilar materials. This paper aims to provide an overview of the state of the art in such joining processes, including cold welding, friction stir welding, self-pierce riveting, mechanical clinching and joining by forming. The paper includes description of the mechanism of joint formation, and analysis of joint performance and applicability. © 2013 CIRP.
Kaiser, Gerald
2001-01-01
The quantum mechanical harmonic oscillator Hamiltonian generates a one-parameter unitary group W(\\theta) in L^2(R) which rotates the time-frequency plane. In particular, W(\\pi/2) is the Fourier transform. When W(\\theta) is applied to any frame of Gabor wavelets, the result is another such frame with identical frame bounds. Thus each Gabor frame gives rise to a one-parameter family of frames, which we call a deformation of the original. For example, beginning with the usual t...
Quantizing Earth surface deformations
Directory of Open Access Journals (Sweden)
C. O. Bowin
2015-03-01
Full Text Available The global analysis of Bowin (2010 used the global 14 absolute Euler pole set (62 Myr history from Gripp and Gordon (1990 and demonstrated that plate tectonics conserves angular momentum. We herein extend that analysis using the more detailed Bird (2003 52 present-day Euler pole set (relative to a fixed Pacific plate for the Earth's surface, after conversion to absolute Euler poles. Additionally, new analytical results now provide new details on upper mantle mass anomalies in the outer 200 km of the Earth, as well as an initial quantizing of surface deformations.
Deformed hyperbolic black holes
Chen, Yu; Lim, Yen-Kheng; Teo, Edward
2015-01-01
Black holes with planar or hyperbolic horizons are known to exist in AdS space, alongside the usual ones with spherical horizons. In this paper, we consider a one-parameter generalisation of these black holes that is contained in the AdS C-metric. In terms of the domain-structure analysis recently developed for such solutions, these black holes have a domain in the shape of a triangle. It is shown that the horizons of these black holes are deformed hyperbolic spaces, with th...
Advanced deformation process modeling
Energy Technology Data Exchange (ETDEWEB)
Kocks, U.F.; Embury, J.D. [Los Alamos National Lab., NM (United States); Beaudoin, A.J. [Reynolds Metals (United States); Dawson, P.R. [Cornell Univ., Ithaca, NY (United States); MacEwen, S.R. [Alcan (Canada); Mecking, H.J. [Hamburg Technic (Germany)
1997-08-01
Progress was made in achieving a comprehensive and coherent description of material behavior in deformation processing. The materials included were metals, alloys, intermetallic compounds, arbitrary lattice structure, and metal matrix composites. Aspects of behavior modeled included kinetics of flow and strain hardening, as well as recrystallization and the various anisotropies of strength and compliance. Highlights include a new prediction of the limiting strength of materials at high temperature, a new understanding of the generation of new grain boundaries during forming operations, and a quantitatively verified computer simulation of texture development and the resulting behavioral anisotropies.
Pseudospin and nuclear deformation
International Nuclear Information System (INIS)
An operator which effects the transformation to the pseudospin representation within the oscillator shell model at arbitrary triaxial deformation is constructed as a special projection of the momentum helicity operator. Since the exact transformation of many important operators cannot be performed in a closed analytical form, a procedure of approximate transformation is developed. In the spherical and asymptotic prolate limits the transforms thus derived reduce to the known exact results. The approximate transform of a modified Nilsson Hamiltonian is found to be almost indistinguishable from the ''pseudo'' Hamiltonian with the strongly reduced spin-orbit strength. (orig.)
Rotary deformity in degenerative spondylolisthesis
International Nuclear Information System (INIS)
We studied to determine whether the degenerative spondylolisthesis has rotary deformity in addition to forward displacement. We have made analysis of difference of rotary deformity between the 31 study groups of symptomatic degenerative spondylolisthesis and 31 control groups without any symptom, statistically. We also reviewed CT findings in 15 study groups. The mean rotary deformity in study groups was 6.1 degree(the standard deviation is 5.20), and the mean rotary deformity in control groups was 2.52 degree(the standard deviation is 2.16)(p < 0.01). The rotary deformity can be accompanied with degenerative spondylolisthesis. We may consider the rotary deformity as a cause of symptomatic degenerative spondylolisthesis in case that any other cause is not detected
Deformation behaviour of dispersion hardened nanocrystalline copper
Directory of Open Access Journals (Sweden)
J.P. Stobrawa
2006-04-01
Full Text Available Purpose: The aim of this work was to describe deformation behaviour of nanocrystalline copper dispersion-hardened with nanoparticles of tungsten carbide and yttria.Design/methodology/approach: Tests were made with the Cu, Cu-WC and Cu-Y2O3 micro-composites containing up to 3 % of a hardening phase. These were obtained by powder metallurgy techniques, i.e. milling the input powders in the planetary ball mills, compacting and sintering. The mechanical properties (hardness, 0,2 YS, elongation during compression test and microstructure were examined by the optical, scanning and transmission electron microscopy.Findings: Analysis of the initial nanocrystalline structure of these materials was made, and its evolution during deformation process was investigated with an account of the hardening effect and the changes in the mechanical and plastic properties. Results of this analysis have been discussed based on the existing theories related to hardening of nanocrystalline materials.Research limitations/implications: The powder metallurgy techniques make it possible to obtain copper-based bulk materials by means of milling input powders in the planetary ball, followed by compacting and sintering. Additional operations of hot extrusion are also often used. There is some threat, however, that during high-temperature processing or using these materials at elevated or high temperatures this nanometric structure may become unstable. The studies have shown the importance of “flows” in the consolidated materials such as pores or regions of poor powder particles joining which significantly deteriorate mechanical properties of compacted and sintered powder micro composites.Practical implications: A growing trend to use new copper-based functional materials is observed recently world-wide. Within this group of materials particular attention is drawn to those with nanometric grain size of a copper matrix, which exhibit higher mechanical properties than microcrystalline copper.Originality/value: The paper contributes to the elucidation of deformation behaviour of high-porosity nanocrystalline copper dispersion hardened with tungsten carbide and yttria.
Deformations of holomorphic Lagrangian fibrations
Sawon, J
2005-01-01
Let $X\\to\\P^n$ be a $2n$-dimensional projective holomorphic symplectic manifold admitting a Lagrangian fibration over $\\P^n$. Matsushita proved that the fibration can be deformed in a codimension one family in the moduli space $\\mathrm{Def}(X)$ of deformations of $X$. We extend his result by proving that if the Lagrangian fibration admits a section, then there is a codimension two family of deformations which also preserve the section.
Deformation processes in polycrystalline Zr by molecular dynamics simulations
Lu, Zizhe; Noordhoek, Mark J.; Chernatynskiy, Aleksandr; Sinnott, Susan B.; Phillpot, Simon R.
2015-07-01
Molecular dynamics simulation is used to characterize the deformation behavior of polycrystalline Zr. The predictions of two different potentials, an embedded atom method potential and a charge optimized many body potential are compared. The experimentally observed prismatic dislocations, pyramidal dislocations and twinning behaviors are produced in the simulations of [ 1 1 2 bar 0 ] and [0 0 0 1] textured structures and in fully 3D structure simulations. The relationship between the generalized stacking fault energy and the mechanical properties is discussed. In particular we find that the different shapes of the generalized stacking-fault energy curve for the two different interatomic descriptions of Zr have a significant effect on the deformation mechanisms. The deformation behavior of Zr is compared with analogous simulations of deformation of polycrystalline Mg.
Computational investigation of plastic deformation in face-centered cubic materials
Semenov, Mikhail; Kolupaeva, Svetlana
2013-01-01
A mathematical model of plastic deformation in face-centered cubic (FCC) materials based on a balance model taking into account fundamental properties of deformation defects of a crystal lattice was developed. This model is based on a system of ordinary differential equations (ODE) accounting for various mechanisms of generation and annihilation of deformation defects for different external conditions. In-house developed software, SPFCC (Slip Plasticity of Face-Centered Cubi...
Berg, L.; Klok, H.J.; Vliet, T. van; van der Linden, E.; Boekel, M.A.J.S., van; Van de Velde, F.
2008-01-01
Microrheology involves simultaneous determination of microstructure and deformation properties, which is essential for understanding structure¿deformation relationships. The unit used combines a confocal laser scanning microscope with a compression unit. The main advantage of this approach is that the changes in the microstructure during deformation can be visualised and quantified in three dimensions. It was used to measure microstructural changes and breakdown mechanisms in whey protein iso...
The two-parameter deformation of GL(2), its differential calculus, and Lie algebra
International Nuclear Information System (INIS)
The Yang-Baxter equation is solved in two dimensions giving rise to a two-parameter deformation of GL(2). The transformation properties of quantum planes are briefly discussed. Non-central determinant and inverse are constructed. A right-invariant differential calculus is presented and the role of the different deformation parameters investigated. While the corresponding Lie algebra relations are simply deformed, the comultiplication exhibits both quantization parameters. (orig.)
Transition in the deformation mode of nanocrystalline tantalum processed by high-pressure torsion
International Nuclear Information System (INIS)
We present quasi-static room temperature compression and nanoindentation data for nanocrystalline and ultrafine grained tantalum processed by high-pressure torsion. Because bulk samples possess an inherent gradient in properties, microstructures were characterized using site-specific transmission electron microscopy and synchrotron X-ray diffraction. Nanocrystalline Ta shows appreciable homogeneous plastic deformation in compression; however, specimens with the smallest grain sizes exhibit localized plastic deformation via shear bands. Microstructural changes associated with this transition in deformation mode are discussed.
Work-Hardening and Deformation Mechanism of Cold Rolled Low Carbon Steel
Wang Su-Fen; Peng Yan; Li Zhi-Jie
2013-01-01
The study reports the mechanical property and microstructure of cold rolled low carbon steel and its work-hardening behavior in the deformation process. The tensile test in room temperature of low carbon steel was implemented for the different cold rolling deformation, the stress-strain curve was draught according to the relationship between strength and deformation and fitted for the polynomial fitting, the strain hardening exponent (n) of test steel was calculated by the Hollomon method. In...
International Nuclear Information System (INIS)
An absolute frequency measurement has been made of the 2S1/2-2F7/2 electric octupole transition in a single ion of 171Yb+. The implementation of a diode-based probe laser stabilized to this highly forbidden transition has resulted in an improvement of more than one order of magnitude upon the lowest published uncertainty. After correcting for systematic shifts, the frequency was determined to be 642 121 496 772 646.22 (67) Hz. This corresponds to a fractional uncertainty of 1.0 × 10-15. (paper)
Umbral Deformations on Discrete Spacetime
Zachos, Cosmas K
2007-01-01
Given a minimum measurable length underlying spacetime, the latter may be effectively regarded as discrete, at scales of order the Planck length. A systematic discretization of continuum physics may be effected most efficiently through the umbral deformation. General functionals yielding such deformations at the level of solutions are furnished and illustrated, and broad features of discrete oscillations and wave propagation are outlined.
Fraktalnist deformational relief polycrystalline aluminum
Directory of Open Access Journals (Sweden)
?.?. ??????????
2006-02-01
Full Text Available The possibility of the fractal geometry method application for the analisys of surface deformation structures under cyclic loading is presented.It is shown, that deformation relief of the alclad aluminium alloyes meets the criteria of the fractality. For the fractal demention estimation the method of “box-counting”can be applied.
Deformation of Man Made Objects
Ibrahim, Mohamed
2012-07-01
We introduce a framework for 3D object deformation with primary focus on man-made objects. Our framework enables a user to deform a model while preserving its defining characteristics. Moreover, our framework enables a user to set constraints on a model to keep its most significant features intact after the deformation process. Our framework supports a semi-automatic constraint setting environment, where some constraints could be automatically set by the framework while others are left for the user to specify. Our framework has several advantages over some state of the art deformation techniques in that it enables a user to add new features to the deformed model while keeping its general look similar to the input model. In addition, our framework enables the rotation and extrusion of different parts of a model.
Transverse deformations of extreme horizons
Li, Carmen
2015-01-01
We consider the inverse problem of determining all extreme black hole solutions to the Einstein equations with a prescribed near-horizon geometry. We investigate this problem by considering infinitesimal deformations of the near-horizon geometry along transverse null geodesics. We show that, up to a gauge transformation, the linearised Einstein equations reduce to an elliptic PDE for the extrinsic curvature of a cross-section of the horizon. We deduce that for a given near-horizon geometry there exists a finite dimensional moduli space of infinitesimal transverse deformations. We then establish a uniqueness theorem for transverse deformations of the extreme Kerr horizon. In particular, we prove that the only smooth axisymmetric transverse deformation of the near-horizon geometry of extreme Kerr, such that cross-sections of the horizon are marginally trapped surfaces, corresponds to that of the extreme Kerr black hole. Furthermore, we determine all smooth and biaxisymmetric transverse deformations of the near-...
Nuclear deformation at finite temperature.
Alhassid, Y; Gilbreth, C N; Bertsch, G F
2014-12-31
Deformation, a key concept in our understanding of heavy nuclei, is based on a mean-field description that breaks the rotational invariance of the nuclear many-body Hamiltonian. We present a method to analyze nuclear deformations at finite temperature in a framework that preserves rotational invariance. The auxiliary-field Monte Carlo method is used to generate a statistical ensemble and calculate the probability distribution associated with the quadrupole operator. Applying the technique to nuclei in the rare-earth region, we identify model-independent signatures of deformation and find that deformation effects persist to temperatures higher than the spherical-to-deformed shape phase-transition temperature of mean-field theory. PMID:25615315
Nuclear deformation at finite temperature
Alhassid, Y; Bertsch, G F
2014-01-01
Deformation, a key concept in our understanding of heavy nuclei, is based on a mean-field description that breaks the rotational invariance of the nuclear many-body Hamiltonian. We present a method to analyze nuclear deformations at finite temperature in a framework that preserves rotational invariance. The auxiliary-field Monte-Carlo method is used to generate the statistical ensemble and calculate the probability distribution associated with the quadrupole operator. Applying the technique to nuclei in the rare-earth region, we identify model-independent signatures of deformation and find that deformation effects persist to higher temperatures than the spherical-to-deformed shape phase-transition temperature of mean-field theory.
Shape Changing Nonlocal Molecular Deformations in a Nematic Liquid Crystal
International Nuclear Information System (INIS)
The nature of nonlinear molecular deformations in a homeotropically aligned nematic liquid crystal (NLC) is presented. We start from the basic dynamical equation for the director axis of a NLC with elastic deformation mapped onto an integro-differential perturbed Nonlinear Schroedinger equation which includes the nonlocal term. By invoking the modified extended tangent hyperbolic function method aided with symbolic computation, we obtain a series of solitary wave solutions. Under the influence of the nonlocality induced by the reorientation nonlinearity due to fluctuations in the molecular orientation, the solitary wave exhibits shape changing property for different choices of parameters. This intriguing property, as a result of the relation between the coherence of the solitary deformation and the nonlocality, reveals a strong need for deeper understanding in the theory of self-localization in NLC systems. (author)
Deformation behaviour of dispersion hardened nanocrystalline copper
J.P. Stobrawa; Z.M. Rdzawski
2006-01-01
Purpose: The aim of this work was to describe deformation behaviour of nanocrystalline copper dispersion-hardened with nanoparticles of tungsten carbide and yttria.Design/methodology/approach: Tests were made with the Cu, Cu-WC and Cu-Y2O3 micro-composites containing up to 3 % of a hardening phase. These were obtained by powder metallurgy techniques, i.e. milling the input powders in the planetary ball mills, compacting and sintering. The mechanical properties (hardness, 0,2 YS, elongation du...
A selection principle in deformation quantization
Gerstenhaber, M
2005-01-01
Deformation quantization produces families of mathematically equivalent quantization procedures from which one must select the physically meaningful ones. As a selection principle we propose that the procedure must allow enough `observable' energy distributions, i.e., ones for which no pure quantum state will appear with negative probability and must further have the property that for these the uncertainty in the probability distribution of the quantum states must not exceed that of the original distribution. For the simple harmonic oscillator we show that this allows only the classic Groenewold-Moyal (skew-symmetric) form.
Exploring Deformation Mechanisms in Nanostructured Materials
Greer, Julia R.; Jang, Dongchan; Gu, X. Wendy
2012-10-01
Useful properties of structural materials generally depend on their bulk microstructure. For centuries, improvements in structural materials relied heavily on processing, which in turn determined the resulting microstructure and properties. Materials sciences are entering an era in which specific properties of a material are obtained not only from its processing but also by controlling of the architecture of its constituents, often with sub-micron dimensions. To utilize this newly achievable nanoscale engineering precision in structural applications, it is imperative to quantify the deformation processes at each relevant scale, with special attention focusing on the importance of internal and external heterogeneities, for example grain boundaries, bi-material interfaces, phase boundaries, etc., on mechanical loading. It has been shown for single crystals that yield (and fracture) strengths increase with power-law dependence on sample size reduction when the micron scale is reached, and therefore, can no longer be inferred from bulk response or from the literature. Although these studies provide a powerful foundation for fundamental deformation processes operating at small scales, they are far from representing real materials used in structural applications, whose microstructure is often complex, containing boundaries and interfaces. Both homogeneous (i.e. grain and twin boundaries) and heterogeneous (i.e. phase and precipitate-matrix boundaries) interfaces in size-limited features are crucial aspects of the structural reliability of most modern materials. They are also of particular importance to damage initiation. This article provides a comprehensive overview of the state-of-the-art experimental and computational methods used to investigate mechanical behavior and microstructural evolution in small-scale metallic systems, deformation of which depends on intricate interactions of defects with internal interfaces and with free surfaces. Attention is focused on the effects of multiple grain boundaries spanning the sample volume (nanocrystalline and polycrystalline metals). This overview sheds light on the relative importance of intrinsic versus extrinsic length scale limitations on deformation mechanisms in nanostructured metals, which has significant implications for the development of new materials with tunable mechanical properties.
Towards ?-deformed D=4 relativistic field theory
International Nuclear Information System (INIS)
Free relativistic fields on noncommutative ?-deformed D=4 Minkowski space are described. Three possible types of ?-deformed Fourier transforms are discussed, related to three different ?-deformed mass-shell conditions. (author)
MM97.48 Influence of multidirectional deformation mode on flow stress behaviour during cold forming
DEFF Research Database (Denmark)
Lindegren, Maria; Pavel, Huml
1997-01-01
In the present experimental investigation the influence of strain path on behaviour and final properties has been simulated in uni-, two- and three-directional deformation regimes. Pure iron and a low carbon steel have been investigated considering stress strain behaviour. Brass and copper specimens which have been undergoing alternate cyclic deformations have been evaluated by hardness measurements, grain size estimation and TEM.
Deformation induced martensite characterization in Fe-30%Ni-5%Cu alloy
Güler E.; Güler M.
2012-01-01
Deformation induced martensite properties were examined according to existing martensite morphology, crystallography and formation temperatures for different prior austenite homogenization conditions in Fe-30%Ni-5%Cu alloy. Scanning electron microscope (SEM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) techniques were employed to investigation. Scanning electron microscope observations showed elongated deformation induced martensite morphology in the austenite ph...
Modelling highly deformable metal extrusion using SPH
Prakash, Mahesh; Cleary, Paul W.
2015-05-01
Computational modelling is often used to reduce trial extrusions through accurate defect prediction. Traditionally, metal extrusion is modelled using mesh based finite element methods. However, large plastic deformations can lead to heavy re-meshing and numerical diffusion. Here we use the mesh-less smoothed particle hydrodynamics method since it allows simulation of large deformations without re-meshing and the tracking of history dependent properties such as plastic strain making it suitable for defect prediction. The variation in plastic strain and deformation for aluminium alloy in a cylindrical 3D geometry with extrusion ratio and die angle is evaluated. The extrusion process is found to have three distinct phases consisting of an initial sharp rise in extrusion force, a steady phase requiring constant force and terminating in a sharp decline in force as metal is completely extruded. Deformation and plastic strain increased significantly with extrusion ratio but only moderately with die angle. Extrusion force increased by 150 % as the extrusion ratio increased from 2:1 to 4:1 but had only a marginal change with die angle. A low strain zone in the centre of the extruded product was found to be a function of extrusion ratio but was persistent and did not vary with die angle. Simulation of a complex 3D building industry component showed large variations in plastic strain along the length of the product at two scales. These were due to change in metal behaviour as extrusion progressed from phase 1 to phase 2. A stagnation zone at the back of the die was predicted that could lead to the "funnel" or "pipe" defect.
International Nuclear Information System (INIS)
The role of different deformation mechanisms in controlling mechanical properties were studied in two low-Ni, Cr–Mn austenitic stainless steel grades (Types 201 and 201L) by tensile testing and microstructure examinations. Tensile tests were carried out at two different strain rates, 5×10?4 and 10?2 s?1, in the temperature range from ?80 °C to 200 °C. It was observed that the flow properties and work hardening rate are affected significantly by temperature and strain rate for the concerned steels through variation of deformation mechanism. Deformation-induced austenite-to-martensite transformation (TRIP effect) is the dominant mechanism at temperatures below room temperature. From 50 °C up to 200 °C, plastic deformation is controlled by mechanical twinning (TWIP effect) and dislocation glide. The electron backscattered diffraction (EBSD) technique and transmission electron microscopy (TEM) were employed to study the plastic deformation accommodation and identify the primary deformation mechanisms operating in the deformed steels.
First applications of the Fayans functional to deformed nuclei
Tolokonnikov, S. V.; Borzov, I. N.; Kortelainen, M.; Lutostansky, Yu S.; Saperstein, E. E.
2015-07-01
First calculations for deformed nuclei using the Fayans functional are carried out for the uranium and lead isotopic chains. The ground state deformations and deformation energies are compared to Skyrme–Hartree–Fock–Bogolyubov HFB-17 and HFB-27 functional results. For the uranium isotopic chain, the Fayans functional property predictions are rather similar to HFB-17 and HFB-27 predictions. However, there is a disagreement for the lead isotopic chain. Both of the Skyrme HFB functionals lead to predictions of rather strong deformations for the light Pb isotopes, which does not agree with the experimental data on charge radii and magnetic moments of the odd Pb isotopes. On the other hand, the Fayans functional leads to the prediction of a spherical ground state for all of the lead isotopes, in accordance with the data and the results known from the literature obtained with the Gogny D1S force and the SLy6 functional as well. The deformation energy curves are calculated and compared against those derived from four Skyrme functionals—SLy4, Sly6, SkM* and UNEDF1—for the 238U nucleus and several lead-deficient Pb isotopes. In the first case, the resulting Fayans functional is rather close to SkM* and UNEDF1, which—in particular the latter—describe the first and second barriers in 238U rather well. For the light lead isotopes, the Fayans deformation energy curves are qualitatively close to those derived from the SLy6 functional.
Time Dependent Volcano Deformation
Segall, P.
2006-12-01
Time varying deformation can arise due to changes in magma pressure, evolution of the source geometry (e.g., dike propagation), or time dependent response of the surrounding crust. It is important to understand the signatures of these processes in order to distinguish between them. Here I explore time dependent surface deformation due to viscoelastic and poroelastic relaxation of the crust surrounding simplified magma chambers. Viscoelastic deformation is considered in a shell surrounding a spherical magma chamber in a half-space (as analyzed numerically by Newman et al, 2001). The full space solution for a Maxwell rheology was given by Dragoni and Magnanensi (PEPI, 1989). An approximate half-space solution is simply constructed following the approach of McTigue (JGR, 1987) as long as the outer radius R2 is small compared to the depth d. The surface displacements are scaled, time-dependent versions of the Mogi solution in an elastic half-space. For a step increase in magma pressure (other source histories are also simply constructed) uz (?, z=0, t) = (1 - ?) p0 R13 / ? d2 [ e-t/tR + R23 / R13 ( 1 - e-t/tR ) ] 1 / (1 + ?2)3/2 where R1 is the magma chamber radius, ? is the normalized radial distance from the center of the source, and the characteristic relaxation time is tR = (3?/?)(1-?)/(1+?)(R2/R1)3, where ? is viscosity and ? is shear modulus. The post-intrusion displacements scale with (R2/R1)3 - 1 and can be significant. For example, a viscoelastic shell of only 20% the radius of the magma chamber leads to time dependent displacements that are 70% of the instantaneous elastic displacements. An approximate fully time-dependent solution for a cylindrical (plane strain) magma chamber in a homogeneous poro-elastic half-space is constructed as the superposition of the solution due to an expanding chamber in a full plane, and distributed shear and normal loads on a poroelastic half-space. The full-space solution is pure shear and thus induces no change in pore pressure. Consequently, the distributed loads necessary to cancel the imposed tractions on the free surface are time invariant. The surface displacements due to the applied surface loads are found using displacement potentials in the Fourier-Laplace domain; the Laplace transforms are inverted analytically. The vertical velocity resulting from the instantaneous inflation of the magma chamber is 2 ? vz(z=0,t) = ? (1-?) [ N? - i sgn(k) T? ] ? c/? t e- c k2 t - c k ?1-? e-? c k2 terfc( ?c (1-?) k2 t) where k is horizontal wavenumber, c is hydraulic diffusivity, ?{1-?} = 1-2?2, ?2 = ?u - ?/1-? , ?u is the undrained Poisson's ratio, and N? and T? are the Fourier transformed normal N and shear T tractions acting on the plane z = 0, N = (? ? V/? ) (x2- d2) /(d2 + x2)2, T = (2? ? V/ ? )dx/(d2 + x2)2. The displacement immediately above the source increases monotonically, however the flanking regions subside for some time following the initial elastic uplift before further uplifting. This arises because pore fluid flows from the flanking region to the center of uplift. The final uplift is identical to the initial elastic uplift but increased by a factor of ?u-?.
The q-deformed Jaynes-Cummings Model and its q-Supercoherent States
Hao, San-Ru; Wang, Lu-Ya
2001-01-01
In this paper, we have proposed a q-deformed Jaynes-Cummings(JC) model and constructed the q-SuperCoherent States(q-SCSs) for the q-deformed JC model. We have also discussed the properties of the q-supercoherent states and given the completeness relation expression. The representation of the q-supercoherent states for the q-deformed JC model is studied as well. PACS number(s): 03.65.Nk Key Works: q-deformed JC model, q-supercoherent states,q-SCSs representation.
Deformation theory of objects in homotopy and derived categories I: general theory
Lunts, V A; Lunts, Valery A.; Orlov, Dmitri
2007-01-01
This is the first paper in a series. We develop a general deformation theory of objects in homotopy and derived categories of DG categories. Namely, for a DG module $E$ over a DG category we define four deformation functors $\\Def ^{\\h}(E)$, $\\coDef ^{\\h}(E)$, $\\Def (E)$, $\\coDef (E)$. The first two functors describe the deformations (and co-deformations) of $E$ in the homotopy category, and the last two - in the derived category. We study their properties and relations. These functors are defined on the category of artinian (not necessarily commutative) DG algebras.
Deformation theory of objects in homotopy and derived categories I: general theory
Efimov, Alexander I.; Lunts, Valery A.; Orlov, Dmitri O.
2007-01-01
This is the first paper in a series. We develop a general deformation theory of objects in homotopy and derived categories of DG categories. Namely, for a DG module $E$ over a DG category we define four deformation functors $\\Def ^{\\h}(E)$, $\\coDef ^{\\h}(E)$, $\\Def (E)$, $\\coDef (E)$. The first two functors describe the deformations (and co-deformations) of $E$ in the homotopy category, and the last two - in the derived category. We study their properties and relations. Thes...
Deforming field theories with $U(1)\\times U(1)$ global symmetry and their gravity duals
Lunin, Oleg; Maldacena, Juan
2005-01-01
We find the gravity dual of a marginal deformation of ${\\cal N}=4$ super Yang Mills, and discuss some of its properties. This deformation is intimately connected with an $SL(2,R)$ symmetry of the gravity theory. The $SL(2,R)$ transformation enables us to find the solutions in a simple way. These field theory deformations, sometimes called $\\beta$ deformations, can be viewed as arising from a star product. Our method works for any theory that has a gravity dual with a $U(1)\\t...
Perceptual transparency from image deformation.
Kawabe, Takahiro; Maruya, Kazushi; Nishida, Shin'ya
2015-08-18
Human vision has a remarkable ability to perceive two layers at the same retinal locations, a transparent layer in front of a background surface. Critical image cues to perceptual transparency, studied extensively in the past, are changes in luminance or color that could be caused by light absorptions and reflections by the front layer, but such image changes may not be clearly visible when the front layer consists of a pure transparent material such as water. Our daily experiences with transparent materials of this kind suggest that an alternative potential cue of visual transparency is image deformations of a background pattern caused by light refraction. Although previous studies have indicated that these image deformations, at least static ones, play little role in perceptual transparency, here we show that dynamic image deformations of the background pattern, which could be produced by light refraction on a moving liquid's surface, can produce a vivid impression of a transparent liquid layer without the aid of any other visual cues as to the presence of a transparent layer. Furthermore, a transparent liquid layer perceptually emerges even from a randomly generated dynamic image deformation as long as it is similar to real liquid deformations in its spatiotemporal frequency profile. Our findings indicate that the brain can perceptually infer the presence of "invisible" transparent liquids by analyzing the spatiotemporal structure of dynamic image deformation, for which it uses a relatively simple computation that does not require high-level knowledge about the detailed physics of liquid deformation. PMID:26240313
ASSESSMENT OF DEFORMATION AND STRENGTH OF SOILS STRENGTHENED BY CEMENTING
Directory of Open Access Journals (Sweden)
Sainov Mihail Petrovich
2014-09-01
Full Text Available Currently there are few studies of deformation and strength properties of loose soils strengthened by cementing. Based on the data of already arranged grout curtains it was determined that in cemented gravel-pebble soil there are 7...9 % of cement, which is less than in concrete. To assess deformation and strength of such soils it is possible to use the data of tests conducted by other authors, where the effect of cement contents on sand-cement mix properties was studied. Analysis of experimental data showed that cemented soil may be identified with concrete only with high content of cement (more than 10 %. At cement content 7...9 % in soil the strength deformation of cemented soil varies to a small extent. Its deformation becomes 2-3 times less. It greatly depends on compression stresses. The formulae are proposed which permit assessing the effect of compression and cement content on deformation of cemented soil. It is shown that strength of cemented soil is less than that even of the weakest concrete. It has a sufficiently high cohesion, but the friction angle is approximately the same as that of the initial soil.
Deformation of phospholipid vesicles in an optical stretcher.
Delabre, Ulysse; Feld, Kasper; Crespo, Eleonore; Whyte, Graeme; Sykes, Cecile; Seifert, Udo; Guck, Jochen
2015-08-14
Phospholipid vesicles are common model systems for cell membranes. Important aspects of the membrane function relate to its mechanical properties. Here we have investigated the deformation behaviour of phospholipid vesicles in a dual-beam laser trap, also called an optical stretcher. This study explicitly makes use of the inherent heating present in such traps to investigate the dependence of vesicle deformation on temperature. By using lasers with different wavelengths, optically induced mechanical stresses and temperature increase can be tuned fairly independently with a single setup. The phase transition temperature of vesicles can be clearly identified by an increase in deformation. In the case of no heating effects, a minimal model for drop deformation in an optical stretcher and a more specific model for vesicle deformation that takes explicitly into account the angular dependence of the optical stress are presented to account for the experimental results. Elastic constants are extracted from the fitting procedures, which agree with literature data. This study demonstrates the utility of optical stretching, which is easily combined with microfluidic delivery, for the future serial, high-throughput study of the mechanical and thermodynamic properties of phospholipid vesicles. PMID:26135540
Structure of the copper under controlled deformation path conditions
Directory of Open Access Journals (Sweden)
D. Kuc
2009-01-01
Full Text Available Purpose: One of the methods of plastic deformation under complex deformation path conditions is compression with oscillatory torsion. The observable effects in the form of changing force parameters and structure changes confirm the possibility of deformation to a value many times higher than in the case of methods traditionally applied for forming. This article presents the results of the influence of compression with oscillatory torsion on structural phenomena occurring in copper deformed in such a way.Design/methodology/approach: The examinations were conducted at a compression/oscillatory torsion test stand. The structural examinations were conducted with the use of light and electron microscopy.Findings: In experimental investigations, a reduction of unit pressures was observed when compared to conventional compression. The structural examinations indicated substantial differences in the mechanisms of plastic deformation conducted in both conventional and combined way.Research limitations/implications: There are premises which show that a metallic material of a nanometric structure can be obtained in this way (top-down method, by the accumulation of great plastic deformation. Metallic materials characterized by grain size below 100nm are distinguished by unconventional properties. Further examinations should focus on conducting experiments in a way that would enable grain size reduction to a nanometric size. This will enable the cumulation of greater deformation in the material.Originality/value: The method of compression with oscillatory torsion is an original method developed at the Silesian University of Technology, owing to which it is possible to obtain high deformation values (SPD without risking the loss of cohesion of the material. Thorough understanding of the changes taking place in the structure of metals subjected to compression with oscillatory torsion will allow the optimal choice of process parameters in order to achieve a gradual grain size reduction.
Structure of the copper under controlled deformation path conditions
Directory of Open Access Journals (Sweden)
G. Niewielski
2009-03-01
Full Text Available Purpose: One of the methods of plastic deformation under complex deformation path conditions is compression with oscillatory torsion. The observable effects in the form of changing force parameters and structure changes confirm the possibility of deformation to a value many times higher than in the case of methods traditionally applied for forming. This article presents the results of the influence of compression with oscillatory torsion on structural phenomena occurring in copper deformed in such a way.Design/methodology/approach: The examinations were conducted at a compression/oscillatory torsion test stand. The structural examinations were conducted with the use of light and electron microscopy.Findings: In experimental investigations, a reduction of unit pressures was observed when compared to conventional compression. The structural examinations indicated substantial differences in the mechanisms of plastic deformation conducted in both conventional and combined way.Research limitations/implications: There are premises which show that a metallic material of a nanometric structure can be obtained in this way (top-down method, by the accumulation of great plastic deformation. Metallic materials characterized by grain size below 100nm are distinguished by unconventional properties. Further examinations should focus on conducting experiments in a way that would enable grain size reduction to a nanometric size. This will enable the cumulation of greater deformation in the material.Originality/value: The method of compression with oscillatory torsion is an original method developed at the Silesian University of Technology, owing to which it is possible to obtain high deformation values (SPD without risking the loss of cohesion of the material. Thorough understanding of the changes taking place in the structure of metals subjected to compression with oscillatory torsion will allow the optimal choice of process parameters in order to achieve a gradual grain size reduction.
Deformation techniques for sparse systems
Jeronimo, G; Solerno, P; Waissbein, A; Jeronimo, Gabriela; Matera, Guillermo; Solerno, Pablo; Waissbein, Ariel
2006-01-01
We exhibit a probabilistic symbolic algorithm for solving zero-dimensional sparse systems. Our algorithm combines a symbolic homotopy procedure, based on a flat deformation of a certain morphism of affine varieties, with the polyhedral deformation of Huber and Sturmfels. The complexity of our algorithm is quadratic in the size of the combinatorial structure of the input system. This size is mainly represented by the mixed volume of Newton polytopes of the input polynomials and an arithmetic analogue of the mixed volume associated to the deformations under consideration.
Deformed spaces and loop cosmology
Battisti, Marco Valerio
2008-01-01
The non-singular bouncing solution of loop quantum cosmology is reproduced by a deformed minisuperspace Heisenberg algebra. This algebra is a realization of the Snyder space, is almost unique and is related to the $\\kappa$-Poincar\\'e one. Since the sign of the deformation parameter it is not fixed, the Friedmann equation of braneworlds theory can also be obtained. Moreover, the sign is the only freedom in the picture and these frameworks are the only ones which can be reproduced by our deformed scheme. A generalized uncertainty principle for loop quantum cosmology is also proposed.
Deformed spaces and loop cosmology
Energy Technology Data Exchange (ETDEWEB)
Battisti, Marco Valerio, E-mail: battisti@icra.i [ICRA and Phys. Department University of Rome ' Sapienza' , P.le A. Moro 5 00185 Rome (Italy)
2009-10-01
The non-singular bouncing solution of loop quantum cosmology is reproduced by a deformed minisuperspace Heisenberg algebra. This algebra is a realization of the Snyder space, is almost unique and is related to the k-Poincare one. Since the sign of the deformation parameter it is not fixed, the Friedmann equation of braneworlds theory can also be obtained. Moreover, the sign is the only freedom in the picture and these frameworks are the only ones which can be reproduced by our deformed scheme. A generalized uncertainty principle for loop quantum cosmology is also proposed.
Deformed spaces and loop cosmology
International Nuclear Information System (INIS)
The non-singular bouncing solution of loop quantum cosmology is reproduced by a deformed minisuperspace Heisenberg algebra. This algebra is a realization of the Snyder space, is almost unique and is related to the k-Poincare one. Since the sign of the deformation parameter it is not fixed, the Friedmann equation of braneworlds theory can also be obtained. Moreover, the sign is the only freedom in the picture and these frameworks are the only ones which can be reproduced by our deformed scheme. A generalized uncertainty principle for loop quantum cosmology is also proposed.
Deformations of generalized holomorphic structures
Wang, Yicao
2014-03-01
A deformation theory of generalized holomorphic structures in the setting of (generalized) principal fibre bundles is developed. It allows the underlying generalized complex structure to vary together with the generalized holomorphic structure. We study the related differential graded Lie algebra, which controls the deformation problem via the Maurer-Cartan equation. As examples, we check the content of the Maurer-Cartan equation in detail in the special cases where the underlying generalized complex structure is symplectic or complex. A deformation theorem, together with some non-obstructed examples, is also included.
Surface processes and deformation in orogenic settings : quantification and modeling
Steer, Philippe
2010-01-01
Among erosion processes, river incision is classicaly described as a key process controlling erosion of landscapes. Incision efficiency is mainly influenced by climate and erodibility. This latter is not only dependent on the nature of the bedrock, but also on its past deformation, which affects its rheological effective properties, such as fracture density. The main objectives of this thesis are: (1) to better constrain the relationship between effective properties and erodibility, and (2) t...
Statics of polymer droplets on deformable surfaces
Léonforte, Fabien
2011-01-01
The equilibrium properties of polymer droplets on a soft deformable surface are investigated by molecular dynamics simulations of a bead-spring model. The surface consists of a polymer brush with irreversibly end-tethered linear homopolymer chains onto a flat solid substrate. We tune the softness of the surface by varying the grafting density. Droplets are comprised of bead-spring polymers of various chain lengths. First, both systems, brush and polymer liquid, are studied independently in order to determine their static and dynamic properties. In particular, using a numerical implementation of an AFM experiment, we measure the shear modulus of the brush surface and compare the results to theoretical predictions. Then, we study the wetting behavior of polymer droplets with different contact angles and on substrates that differ in softness. Density profiles reveal, under certain conditions, the formation of a wetting ridge beneath the three-phase contact line. Cap-shaped droplets and cylindrical droplets are a...
Nonlinear Deformable-body Dynamics
Luo, Albert C J
2010-01-01
"Nonlinear Deformable-body Dynamics" mainly consists in a mathematical treatise of approximate theories for thin deformable bodies, including cables, beams, rods, webs, membranes, plates, and shells. The intent of the book is to stimulate more research in the area of nonlinear deformable-body dynamics not only because of the unsolved theoretical puzzles it presents but also because of its wide spectrum of applications. For instance, the theories for soft webs and rod-reinforced soft structures can be applied to biomechanics for DNA and living tissues, and the nonlinear theory of deformable bodies, based on the Kirchhoff assumptions, is a special case discussed. This book can serve as a reference work for researchers and a textbook for senior and postgraduate students in physics, mathematics, engineering and biophysics. Dr. Albert C.J. Luo is a Professor of Mechanical Engineering at Southern Illinois University, Edwardsville, IL, USA. Professor Luo is an internationally recognized scientist in the field of non...
Shape Deformations in Atomic Nuclei
Hamamoto, Ikuko
2011-01-01
The ground states of some nuclei are described by densities and mean fields that are spherical, while others are deformed. The existence of non-spherical shape in nuclei represents a spontaneous symmetry breaking.
Cosmetic and Functional Nasal Deformities
... other anomaly (problem) may have structural weakness or asymmetry of the nose. Congenital nasal deformities may require ... see the Rhinoplasty Patient Education topic for more information. A “Septoplasty” is a surgery used to straighten ...
Variable focal length deformable mirror
Headley, Daniel (Albuquerque, NM); Ramsey, Marc (Albuquerque, NM); Schwarz, Jens (Albuquerque, NM)
2007-06-12
A variable focal length deformable mirror has an inner ring and an outer ring that simply support and push axially on opposite sides of a mirror plate. The resulting variable clamping force deforms the mirror plate to provide a parabolic mirror shape. The rings are parallel planar sections of a single paraboloid and can provide an on-axis focus, if the rings are circular, or an off-axis focus, if the rings are elliptical. The focal length of the deformable mirror can be varied by changing the variable clamping force. The deformable mirror can generally be used in any application requiring the focusing or defocusing of light, including with both coherent and incoherent light sources.
Plastic Deformation of Metal Surfaces
DEFF Research Database (Denmark)
Hansen, Niels; Zhang, Xiaodan
2013-01-01
Plastic deformation of metal surfaces by sliding and abrasion between moving parts can be detrimental. However, when the plastic deformation is controlled for example by applying different peening techniques hard surfaces can be produced which can increase the fracture resistance and fatigue life of metal components. An optimization of processes and material parameters must be based on a quantification of stress and strain gradients at the surface and in near surface layer where the structural scale can reach few tens of nanometers. For such fine structures it is suggested to quantify structural parameters by TEM and EBSD and apply strength-structural relationships established for the bulk metal deformed to high strains. This technique has been applied to steel deformed by high energy shot peening and a calculated stress gradient at or near the surface has been successfully validated by hardness measurements as a function of distance from the surface.
Relativistic Hartree-Bogoliubov description of the deformed ground-state proton emitters
Vretenar; Lalazissis, G. A.; RING, P.
1998-01-01
Ground-state properties of deformed proton-rich odd-Z nuclei in the region $59 \\leq Z \\leq 69$ are described in the framework of Relativistic Hartree Bogoliubov (RHB) theory. One-proton separation energies and ground-state quadrupole deformations that result from fully self-consistent microscopic calculations are compared with available experimental data. The model predicts the location of the proton drip-line, the properties of proton emitters beyond the drip-line, and prov...
Non-Isothermal, Multi-phase, Multi-component Flows through Deformable Methane Hydrate Reservoirs
Gupta, Shubhangi; Helmig, Rainer; Wohlmuth, Barbara
2015-01-01
We present a hydro-geomechanical model for subsurface methane hydrate systems. Our model considers kinetic hydrate phase change and non-isothermal, multi-phase, multi-component flow in elastically deforming soils. The model accounts for the effects of hydrate phase change and pore pressure changes on the mechanical properties of the soil, and also for the effect of soil deformation on the fluid-solid interaction properties relevant to reaction and transport processes (e.g., ...
AgSnBi powder consolidated by composite mode of deformation
M. Richert; J. Richert; B. Leszczy?ska - Madej; A. Hotlo?; M. Ma?lanka; W. Pachla; J. Skiba
2010-01-01
Purpose: The objective of this work present the characterization of microstructure and properties of consolidated powder AgSn7.5Bi0.5 by using composition of cyclic extrusion compression (CEC) and hydrostatic extrusion (HE) methods. As the final product the wires of 3 mm in diameter were obtained. The comparison of powder properties after CEC deformation and after the combined deformation CEC and HE is presented.Design/methodology/approach: The investigated samples contained consolidated by l...
Deterritorializing Drawing - transformation/deformation
DEFF Research Database (Denmark)
Brabrand, Helle
2012-01-01
Abstract The paper questions concepts of transformation and deformation in architectural becoming. Provoked by the role of diagram and transformation dominating actual discussions, I state the role of deformation as an equal category of composing. Deleuze, with Bacon, refers to transformation and deformation as two very different categories. Moves of transformation produce new places or singularities in a series, making a Figure emerge that switches between force and form and between transformation and deformation. Deformation is acted out by sensation, passing from one ‘order’ to another. Bacon criticises figurative as well as abstract painting as passing through the brain and not acting directly upon the senses. Figurative and abstract painting both fail to liberate the Figure, implementing transformation of form, but not attaining deformations of bodies. Bacon, then, is concerned about deformation, about painting the sensation, which is essentially rhythm, making Figure-rhythm relations appear as vibrations that flow through the body - making resonance. Deleuze, with Bergson, argues that art extracts ’a little time in a pure state’ from the everyday repetitions, and thereby opens the capacity of the body to be affected by change. The everyday and the ceremonial body, the ordinary and the aberrant movement – these poles generate a passage rather than a difference from the one to the other: from attitude or position to gesture or kinaesthetic twist. Known from without through perception but also from within by sensations, body ‘images’ are different to all other images. Twisting these body images make a mode of operation of art. The paper will address the above issues discussing modes of operation and appearance of my actual project. Acting in the reality of drawing, the project confront the body, situated in real time and depth, with drawing transforming and deforming time and depth.
Nuclear deformation at finite temperature
Alhassid, Y.; Gilbreth, C. N.; Bertsch, G. F.
2014-01-01
Deformation, a key concept in our understanding of heavy nuclei, is based on a mean-field description that breaks the rotational invariance of the nuclear many-body Hamiltonian. We present a method to analyze nuclear deformations at finite temperature in a framework that preserves rotational invariance. The auxiliary-field Monte-Carlo method is used to generate the statistical ensemble and calculate the probability distribution associated with the quadrupole operator. Applyi...
Rendering Deformable Surface Reflectance Fields
Weyrich, Tim; Pfister, Hanspeter; Gross, Markus
2005-01-01
Animation of photorealistic computer graphics models is an important goal for many applications. Image-based modeling has emerged as a promising approach to capture and visualize real-world objects. Animating image-based models, however, is still a largely unsolved problem. In this paper, we extend a popular image-based representation called surface reflectance field to animate and render deformable real-world objects under arbitrary illumination. Deforming the surface reflectance field is ac...
3D brain mapping using a deformable neuroanatomy
International Nuclear Information System (INIS)
This paper presents two different mathematical methods that can be used separately or in conjunction to accommodate shape variabilities between normal human neuroanatomies. Both methods use a digitized textbook to represent the complex structure of a typical normal neuroanatomy. Probabilistic transformations on the textbook coordinate system are defined to accommodate shape differences between the textbook and images of other normal neuroanatomies. The transformations are constrained to be consistent with the physical properties of deformable elastic solids in the first method and those of viscous fluids in the second. Results presented in this paper demonstrate how a single deformable textbook can be used to accommodate normal shape variability. (Author)
Fission characteristics of individual deformation paths in heavy elements
International Nuclear Information System (INIS)
The deformation properties of heavy nuclei undergoing the individual fission paths are studied. To understand the nuclear mass division process at low energy, fission events for the symmetric and asymmetric fission paths are analyzed from the overall fission events. The fragment mass-yield distributions for the symmetric and asymmetric fission paths in the fission processes of 210Po, 227Ac, 233Pa, 249Bk, and 259Md are systematically studied. Fission characteristics including the deformation of the fissioning nucleus at the scission configuration, the fragment mass-yield distributions, and the total kinetic energy release for individual fission paths are presented. (author)
Single point deformation and abrasion of ?-irradiated poly(tetrafluoroethylene)
International Nuclear Information System (INIS)
During the sliding of solid bodies over one another, frictional work is dissipated which may lead to deformation or damage of one or both of the surfaces. This paper shows that it is not the magnitude of the work which controls the extent of deformation, but the way in which the work is dissipated. Three non-interacting dissipation processes are envisaged: hysteresis losses, plastic or viscoelastic ploughing and brittle fracture. Using single point scratching experiments the contributions of these processes to the total work have been estimated for a series of PTFES whose mechanical properties have been varied by exposure to increasing levels of ?-irradiation. (author)
Deformation characteristics of 2-3 km buried Hota accretionary complex, central Japan
Yamamoto, Y.; Yamaguchi, H.; Kameda, J.
2008-12-01
The lower to middle Miocene Hota accretionary complex is a unique example of on land accretionary complex, representing deformation and its physical/chemical properties of sediments just prior to entering the seismogenic realm. The maximum paleotemperature was estimated approximately 55-70°C (based on vitrinite reflectance) indicative of a maximum burial depth about 2-3 km assuming a paleo-geothermal gradient as 25-35°C/km. Accretionary complex in this temperature/depth range corresponds with an intermediate range between the core samples collected from the modern accretionary prism (e.g. Nankai, Barbados, and so on) and rocks in the ancient accretionary complexes on land. Deformation and physical/chemical properties of accretionary complex in this range were poorly understood because the appropriate samples have not been collected yet (scientific drilling has never reached there and most of ancient examples experienced the deeper burial depth and suffered thermal and physical overprinting). This presentation will treat the detailed structural and chemical analyses of the Hota accretionary complex to construct deformation properties of accretionary complex in its 2-3 km depth range and to discuss the interrelation between the early diagenesis (hydrocarbon/cations generation and sediment dewatering, etc.) and transition of the deformation properties. The deformation in this accretionary complex is characterized by two deformation styles: one is a few centimeter-scale phacoidal deformation representing clay minerals preferred orientation in the outer rim, whereas random fabric in the core, quite similar texture to the rocks in the present-Nankai décollement zone. The other is S-C style deformation (similar deformation to the mélanges in ancient accretionary complex on land) exhibiting block-in-matrix texture and quite intense clay minerals preferred orientation in the matrix, cutting the phacoidal deformation. Positive anomaly of illite/smectite ratio and vitrinite reflectance data (Ro) inside the latter S-C structure infers frictional heating during the deformation. Carbonate cement and calcite/dolomite-filled breccias above the S- C deformation and sandstone clasts representing hydro-fractured texture in the deformation are indicative that calcareous cement and pore-fluid pressure fluctuations seemed to be an essential control of the transition of the deformation style and position of the S-C style deformation.
Twisted Deformation Quantization of Algebraic Varieties (Survey)
Yekutieli, Amnon
2008-01-01
Let X be a smooth algebraic variety over a field of characteristic 0. We introduce the notion of twisted associative (resp. Poisson) deformation of the structure sheaf O_X. These are stack-like versions of usual deformations. We prove that there is a twisted quantization map from twisted Poisson deformations to twisted associative deformations, which is canonical and bijective on equivalence classes.
Time-resolved biofilm deformation measurements using optical coherence tomography.
Blauert, Florian; Horn, Harald; Wagner, Michael
2015-09-01
The interaction of shear stress with the biofilm leads to a dynamic deformation, which is related to the structural and material characteristics of biofilms. We show how optical coherence tomography can be used as an imaging technique to investigate the time-resolved deformation on the biofilm mesoscale as well as to estimate mechanical properties of the biofilm. For the first time time-resolved deformation from cross-sectional views of the inner biofilm structure could be shown. Changes in the biofilm structure and rheological properties were calculated from cross sections in real-time and time-lapsed measurements. Heterotrophic biofilms were grown in a flow cell set-up at low shear stress of ?w? =?0.01?Pa. By applying higher shear stress elastic and viscoelastic behavior of biofilms were quantified. Deformation led to a change in biofilm conformation and allowed to estimate rheological properties. Assuming an ideal wall shear stress calculation, the shear modulus G?=?29.7?±?1.7?Pa and the Young's modulus E?=?36.0?±?2.6?Pa were estimated. PMID:25786671
Analysis of Mining Terrain Deformation Characteristics with Deformation Information System
Blachowski, Jan; Milczarek, Wojciech; Grzempowski, Piotr
2014-05-01
Mapping and prediction of mining related deformations of the earth surface is an important measure for minimising threat to surface infrastructure, human population, the environment and safety of the mining operation itself arising from underground extraction of useful minerals. The number of methods and techniques used for monitoring and analysis of mining terrain deformations is wide and increasing with the development of geographical information technologies. These include for example: terrestrial geodetic measurements, global positioning systems, remote sensing, spatial interpolation, finite element method modelling, GIS based modelling, geological modelling, empirical modelling using the Knothe theory, artificial neural networks, fuzzy logic calculations and other. The aim of this paper is to introduce the concept of an integrated Deformation Information System (DIS) developed in geographic information systems environment for analysis and modelling of various spatial data related to mining activity and demonstrate its applications for mapping and visualising, as well as identifying possible mining terrain deformation areas with various spatial modelling methods. The DIS concept is based on connected modules that include: the spatial database - the core of the system, the spatial data collection module formed by: terrestrial, satellite and remote sensing measurements of the ground changes, the spatial data mining module for data discovery and extraction, the geological modelling module, the spatial data modeling module with data processing algorithms for spatio-temporal analysis and mapping of mining deformations and their characteristics (e.g. deformation parameters: tilt, curvature and horizontal strain), the multivariate spatial data classification module and the visualization module allowing two-dimensional interactive and static mapping and three-dimensional visualizations of mining ground characteristics. The Systems's functionality has been presented on the case study of a coal mining region in SW Poland where it has been applied to study characteristics and map mining induced ground deformations in a city in the last two decades of underground coal extraction and in the first decade after the end of mining. The mining subsidence area and its deformation parameters (tilt and curvature) have been calculated and the latter classified and mapped according to the Polish regulations. In addition possible areas of ground deformation have been indicated based on multivariate spatial data analysis of geological and mining operation characteristics with the geographically weighted regression method.
Highly Deformable Graphene Kirigami
Qi, Zenan; Park, Harold S.; Campbell, David K.
2014-01-01
Graphene's exceptional mechanical properties, including its highest-known stiffness (1 TPa) and strength (100 GPa) have been exploited for various structural applications. However, graphene is also known to be quite brittle, with experimentally-measured tensile fracture strains that do not exceed a few percent. In this work, we introduce the notion of graphene kirigami, where concepts that have been used almost exclusively for macroscale structures are applied to dramaticall...
Preferred orientation in experimentally deformed stishovite: implications for deformation mechanisms
Kaercher, P. M.; Zepeda-Alarcon, E.; Prakapenka, V.; Kanitpanyacharoen, W.; Smith, J.; Sinogeikin, S. V.; Wenk, H. R.
2014-12-01
The crystal structure of the high pressure SiO2 polymorph stishovite has been studied in detail, yet little is known about its deformation mechanisms. Information about how stishovite deforms under stress is important for understanding subduction of quartz-bearing crustal rocks into the mantle. Particularly, stishovite is elastically anisotropic and thus development of crystallographic preferred orientation (CPO) during deformation may contribute to seismic anomalies in the mantle. We converted a natural sample of flint to stishovite in a laser heated diamond anvil cell and compressed the stishovite aggregate up to 38 GPa. Diffraction patterns were collected in situ in radial geometry at the Advanced Light Source (ALS) and the Advanced Photon Source (APS) to examine development of CPO during deformation. We find that (001) poles preferentially align with the compression direction and infer deformation mechanisms leading to the observed CPO with visco-plastic self consistent (VPSC) polycrystal plasticity models. Our results show pyramidal and basal slip are most likely active at high pressure and ambient temperature, in agreement with transmission electron microscopy (TEM) studies of rutile (TiO2) and paratellurite (TeO2), which are isostructural to stishovite. Conversely other TEM studies of stishovite done at higher temperature suggest dominant prismatic slip. This indicates that a variety of slip systems may be active in stishovite, depending on conditions. As a result, stishovite's contribution to the seismic signature in the mantle may vary as a function of pressure and temperature and thus depth.
Derivatives, forms and vector fields on the ?-deformed Euclidean space
International Nuclear Information System (INIS)
The model of ?-deformed space is an interesting example of a noncommutative space, since it allows a deformed symmetry. In this paper, we present new results concerning different sets of derivatives on the coordinate algebra of ?-deformed Euclidean space. We introduce a differential calculus with two interesting sets of one-forms and higher-order forms. The transformation law of vector fields is constructed in accordance with the transformation behaviour of derivatives. The crucial property of the different derivatives, forms and vector fields is that in an n-dimensional spacetime there are always n of them. This is the key difference with respect to conventional approaches, in which the differential calculus is (n + 1)-dimensional. This work shows that derivative-valued quantities such as derivative-valued vector fields appear in a generic way on noncommutative spaces
Noncommutative deformations of quantum field theories, locality, and causality
Soloviev, Michael A
2010-01-01
We investigate noncommutative deformations of quantum field theories for different star products, particularly emphasizing the locality properties and the regularity of the deformed fields. Using functional analysis methods, we describe the basic structural features of the vacuum expectation values of star-modified products of fields and field commutators. As an alternative to microcausality, we introduce a notion of $\\theta$-locality, where $\\theta$ is the noncommutativity parameter. We also analyze the conditions for the convergence and continuity of star products and define the function algebra that is most suitable for the Moyal and Wick-Voros products. This algebra corresponds to the concept of strict deformation quantization and is a useful tool for constructing quantum field theories on a noncommutative space-time.
Interfacially Driven Deformation Twinning in Bulk Ag-Cu Composites
Mara, N. A.; Beyerlein, I. J.; Carpenter, J. S.; Wang, J.
2012-10-01
Interfaces and interface/defect interactions increasingly dominate the mechanical response of materials as the dimensions of the grains decrease to the nanoscale. Recently, we reported unusually profuse deformation twinning in Ag-Cu layered eutectic composites with bilayer thicknesses in the submicron regime (~200 nm-400 nm) at room temperature and low strain rates. Using atomistic simulations and dislocation theory, we propose that the Ag-Cu interface facilitated deformation twinning in Cu by permitting the transmission of twinning partials from Ag to Cu. In this way, twins in Ag can provide an ample supply of twinning partials to Cu to support and sustain twin growth in Cu during deformation. Interface-driven twinning as revealed by this study suggests the exciting possibility of altering the roles of dislocation slip and twinning through the design of heterophase interface structure and properties.
Uncertainty relations for a q-deformed coherent spin state
International Nuclear Information System (INIS)
A Coherent Spin State (CSS) is defined as an eigenstate of the spin component in the direction specified by angles (?0,?0). This state satisfies minimum uncertainty relation, with uncertainties equally distributed on any two orthogonal components normal to the direction of the total spin vector ?S?. Starting from this concept, we apply the notion of CSS to quantum groups and discuss the properties of q-deformed CSS and the associated uncertainty relations. We show that these states behave as Intelligent Spin States (ISS) on two orthogonal components normal to the direction of the mean value of the spin operator. -- Highlights: ? q-Deformed Coherent Spin States (q-CSS) and Intelligent Spin States (ISS). ? The squeezing parameters and the parallelism between q-CSS and ISS. ? Applications of deformed groups and algebras to the field of spin systems.
Mechanical behaviour of nuclear structural materials: deformation, fatigue and fracture
International Nuclear Information System (INIS)
It is required to develop new and improved mechanical test methods, characterization methodology and, techniques of analysing and modeling of mechanical properties, to assess performance of structural materials under various conditions of deformation that are experienced in both processing and service. In the following sections we propose to cover briefly some of our activities on determination of fracture toughness of pressure tube materials, optimization of hot working parameters of zirconium base alloys, and understanding the effect of alloying on hot deformation behaviour. This will be followed by highlighting some recent work on the understanding the cyclic deformation behaviour of primary heat transport piping steel (SA 333 Gr. 6) at room temperature and by describing our efforts to characterize the fracture behaviour of thin tubular components. In addition to these, some new results on characterization of fracture behaviour of new generation ferritic steel for pressure vessel application will be presented with emphasis on determination of T0 parameter and master curve. (author)
A submicron mild steel produced by simple warm deformation
International Nuclear Information System (INIS)
One simple deformation process, through which a submicron ferrite grained mild steel was fabricated, was introduced. According to the transmission electron microscope images of the microstructures, most of the boundaries formed during the process might be low angle boundaries, which means that most of the ultrafine grains are subgrains. This deformation process is attractive because: (1) the necessary strain was only 1.5, (2) the deformation resistance decreased due to higher rolling temperature, and (3) the as warm-rolled mild steel had a microstructure with equiaxed grains of 0.7 ?m in average diameter. The result of mechanical tests indicates that better properties, with comparison to its coarse-grained counterpart, were obtained, including doubled yield strength, high hardness, good work hardening and reliable elongation. Cross effect was observed during tensile process and interpreted from point view of conventional dislocation movement
Bilateral cleft lip nasal deformity
Directory of Open Access Journals (Sweden)
Singh Arun
2009-01-01
Full Text Available Bilateral cleft lip nose deformity is a multi-factorial and complex deformity which tends to aggravate with growth of the child, if not attended surgically. The goals of primary bilateral cleft lip nose surgery are, closure of the nasal floor and sill, lengthening of the columella, repositioning of the alar base, achieving nasal tip projection, repositioning of the lower lateral cartilages, and reorienting the nares from horizontal to oblique position. The multiplicity of procedures in the literature for correction of this deformity alludes to the fact that no single procedure is entirely effective. The timing for surgical intervention and its extent varies considerably. Early surgery on cartilage may adversely affect growth and development; at the same time, allowing the cartilage to grow in an abnormal position and contributing to aggravation of deformity. Some surgeons advocate correction of deformity at an early age. However, others like the cartilages to grow and mature before going in for surgery. With peer pressure also becoming an important consideration during the teens, the current trend is towards early intervention. There is no unanimity in the extent of nasal dissection to be done at the time of primary lip repair. While many perform limited nasal dissection for the fear of growth retardation, others opt for full cartilage correction at the time of primary surgery itself. The value of naso-alveolar moulding (NAM too is not universally accepted and has now more opponents than proponents. Also most centres in the developing world have neither the personnel nor the facilities for the same. The secondary cleft nasal deformity is variable and is affected by the extent of the original abnormality, any prior surgeries performed and alteration due to nasal growth. This article reviews the currently popular methods for correction of nasal deformity associated with bilateral cleft lip, it?s management both at the time of cleft lip repair and also secondarily, at a later date. It also discusses the practices followed at our centre.
Plastic Deformation of Quartz: Unfinished business?
Paterson, M. S.
2011-12-01
Starting at Harvard in the mid-1930's, David Griggs built a series of high pressure machines for experimental rock deformation. One persistent aim was to achieve the plastic deformation of quartz. Each time he built a new machine for higher pressure and/or temperature, one of the first materials he tested would be quartz. This search went on through a 500 MPa liquid-medium machine at temperatures up to 300°C, then with a gas-medium machine for temperatures up to 800°C, and finally with a solid-medium machine for higher pressures and temperatures. Quartz proved stubbornly resistant to deformation except at extremely high stresses until, finally and somewhat serendipitously, it was found possible to deform quartz at relatively low stresses in the presence of water under special conditions. The breakthrough came in an experiment in a 1500 MPa solid-medium apparatus in which talc was used as pressure medium. At the temperature of the experiment, the talc dehydrated and so released water. Under these conditions, natural quartz proved to be very weak and to readily undergo plastic deformation, a phenomenon that became known as "hydrolytic weakening". Soon after this discovery, it was also found that certain synthetic single crystals could be easily deformed ab initio. These crystals were from a particular set that had been grown rapidly under hydrothermal conditions and had incorporated water during growth. Attempts in our laboratory to weaken crystals in a gas-medium apparatus at around 300 MPa by cooking dry quartz in the presence of added water were all unsuccessful, although we could deform wet synthetic crystals. There was considerable speculation about a role of high pressure in promoting hydrolytic weakening, but the dilemma was eventually clarified by electron microscope studies by Fitz Gerald and coworkers. These studies showed that crystals that had been subjected to high pressure and temperature in the solid-medium apparatus were extensively microcracked, presumably due to non-hydrostatic stresses generated from the solid medium during raising the pressure, thus evidently promoting the ingress of water. From our gas-medium experiments it would seem that both the solubility and the rate of diffusion of water-related species in dry quartz must be very low, such that at 300 MPa and around 500 - 1000 °C the water penetrates less than a few micrometres in the course of a few hours. Thus the sluggishness of diffusion and the low equilibrium solubility of water-related species in quartz probably explain the failure to achieve hydrolytic weakening in the gas-medium apparatus. However, the documentation of these properties remains inadequate. The initial, and still current, Frank-Griggs hypothesis for the origin of hydrolytic weakening is that the water plays a role in the breaking of the covalent silicon-oxygen bonds as a dislocation is propagated. It is a corollary that the dislocation must be saturated with water or that the water must migrate with the dislocation as it moves. Heggie and Jones have done a number of ab initio calculations on the role of the water in the migration of dislocations in quartz which support the idea that the motion of dislocations is aided by the presence of water-related species in the dislocation core.
Elastic Deformation of Polycrystals
Ahluwalia, R; Saxena, A; Ahluwalia, Rajeev; Lookman, Turab; Saxena, Avadh
2002-01-01
We propose a framework to model elastic properties of polycrystals by coupling crystal orientational degrees of freedom with elastic strains. Our model encodes crystal symmetries and takes into account explicitly the strain compatibility induced long-range interaction between grains. The coupling of crystal orientation and elastic interactions allows for the rotation of individual grains by an external load. We apply the model to simulate uniaxial tensile loading of a 2D polycrystal within linear elasticity and a system with elastic anharmonicities that describe structural phase transformations. We investigate the constitutive response of the polycrystal and compare it to that of single crystals with crystallographic orientations that form the polycrystal.
[Visual-haptic simultaneity judgments for dynamic deformation].
Takahashi, Kohske; Saiki, Jun
2008-02-01
Simultaneity is important in cross-modal information processing. However, it is still unclear how simultaneity is perceived between different sensory modalities. Various factors such as spatial location or attention are known to affect simultaneity judgments. In the present study, we focused on the simultaneity judgments of dynamic events, and investigated what kinds of dynamic properties affect these judgments. We presented the deformation of a virtual object in vision and haptics with various stimulus onset asynchronies. Participants judged whether the deformation occurred simultaneously. We measured the effects of duration, velocity, and the amount of deformation on the visual-haptic simultaneity judgments. The results showed that the point of subjective simultaneity changed depending on the duration of deformation. For a shorter duration (400 ms), the visual deformation needed to precede the haptic one to be judged as simultaneous, while for a longer duration (800 ms, 1 200 ms), the asymmetry was diminished, suggesting that information relevant to the duration of the event was used for the vision-haptics simultaneity judgments of dynamic events. PMID:18402062
Plastic deformation of triblock elastomers by molecular simulation
Parker, Amanda; Rottler, Jörg
2015-03-01
The mechanical properties of thermoplastic elastomers (TPE) can be greatly enhanced by exploiting the complex morphology of triblock copolymers. A common strategy consists of confining chain ends into hard glassy regions that effectively crosslink a soft rubbery phase. We present molecular dynamics simulations that provide insight into key microscopic behaviour of the copolymer chains during deformation. First, a coarse-grained polymer model with an ABA type configuration and soft interactions is employed to achieve equilibrated spherical morphologies. Our model TPEs contain at least 30 spheres in order to ensure configurational averaging. Elastoplastic deformation with uniaxial extension or volume conserving shear is then studied after hard excluded volume interactions have been reintroduced. We consider trends of stress-strain curves for different chain lengths, and compare to equivalent homopolymeric systems. During deformation we simultaneously track the evolution of the number and shape of the minority spheres, the proportion of chains bridging from one sphere to another, as well as local plastic deformation. The simulations reveal strong differences between deformation modes, the evolution of sphere morphology and chain anisotropy.
Quantifying torso deformity in scoliosis
Ajemba, Peter O.; Kumar, Anish; Durdle, Nelson G.; Raso, V. James
2006-03-01
Scoliosis affects the alignment of the spine and the shape of the torso. Most scoliosis patients and their families are more concerned about the effect of scoliosis on the torso than its effect on the spine. There is a need to develop robust techniques for quantifying torso deformity based on full torso scans. In this paper, deformation indices obtained from orthogonal maps of full torso scans are used to quantify torso deformity in scoliosis. 'Orthogonal maps' are obtained by applying orthogonal transforms to 3D surface maps. (An 'orthogonal transform' maps a cylindrical coordinate system to a Cartesian coordinate system.) The technique was tested on 361 deformed computer models of the human torso and on 22 scans of volunteers (8 normal and 14 scoliosis). Deformation indices from the orthogonal maps correctly classified up to 95% of the volunteers with a specificity of 1.00 and a sensitivity of 0.91. In addition to classifying scoliosis, the system gives a visual representation of the entire torso in one view and is viable for use in a clinical environment for managing scoliosis.
Heterogeneous Deformable Modeling of Bio-Tissues and Haptic Force Rendering for Bio-Object Modeling
Lin, Shiyong; Lee, Yuan-Shin; Narayan, Roger J.
This paper presents a novel technique for modeling soft biological tissues as well as the development of an innovative interface for bio-manufacturing and medical applications. Heterogeneous deformable models may be used to represent the actual internal structures of deformable biological objects, which possess multiple components and nonuniform material properties. Both heterogeneous deformable object modeling and accurate haptic rendering can greatly enhance the realism and fidelity of virtual reality environments. In this paper, a tri-ray node snapping algorithm is proposed to generate a volumetric heterogeneous deformable model from a set of object interface surfaces between different materials. A constrained local static integration method is presented for simulating deformation and accurate force feedback based on the material properties of a heterogeneous structure. Biological soft tissue modeling is used as an example to demonstrate the proposed techniques. By integrating the heterogeneous deformable model into a virtual environment, users can both observe different materials inside a deformable object as well as interact with it by touching the deformable object using a haptic device. The presented techniques can be used for surgical simulation, bio-product design, bio-manufacturing, and medical applications.
Work-Hardening and Deformation Mechanism of Cold Rolled Low Carbon Steel
Directory of Open Access Journals (Sweden)
Wang Su-Fen
2013-01-01
Full Text Available The study reports the mechanical property and microstructure of cold rolled low carbon steel and its work-hardening behavior in the deformation process. The tensile test in room temperature of low carbon steel was implemented for the different cold rolling deformation, the stress-strain curve was draught according to the relationship between strength and deformation and fitted for the polynomial fitting, the strain hardening exponent (n of test steel was calculated by the Hollomon method. In the whole cold deformation process, the work-hardening of cold rolled steel is significant, work-hardening rate has different degrees decreasewith the deformation increase. The strain hardening exponent is simple and dislocation strengthening is the major cause of hardening processing. The microstructure of test steel was observed after different deformation, the room temperature organization is the ferrite and few pearlite. The original grain is equiaxial and the average grain size is about 23.5 um, and pearlite distributes in ferrite grain boundaries. It was consequently established the cold deformation energy according to dislocation model, the cold deformation energy is main concerned on the plastic deformation to resistance and the initial stress.
On deformations of triangulated models
De Deken, Olivier
2012-01-01
This paper is the first part of a project aimed at understanding deformations of triangulated categories, and more precisely their dg and A infinity models, and applying the resulting theory to the models occurring in the Homological Mirror Symmetry setup. In this first paper, we focus on models of derived and related categories, based upon the classical construction of twisted objects over a dg or $A_{\\infty}$-algebra. For a Hochschild 2 cocycle on such a model, we describe a corresponding "curvature compensating" deformation which can be entirely understood within the framework of twisted objects. We unravel the construction in the specific cases of derived A infinity and abelian categories, homotopy categories, and categories of graded free qdg-modules. We identify a purity condition on our models which ensures that the structure of the model is preserved under deformation. This condition is typically fulfilled for homotopy categories, but not for unbounded derived categories.
Extraordinary deformation capacity of smallest carbohelicene springs.
Šesták, Petr; Wu, Jianyang; He, Jianying; Pokluda, Jaroslav; Zhang, Zhiliang
2015-07-01
The extraordinary deformation and loading capacity of nine different [?]carbohelicene springs under uniaxial tension up to their fracture were computed using the density functional theory. The simulations comprised either the experimentally synthetized springs of hexagonal rings or the hypothetical ones that contained irregularities (defects) as, for example, pentagons replacing the hexagons. The results revealed that the presence of such defects can significantly improve mechanical properties. The maximum reversible strain varied from 78% to 222%, the maximum tensile force varied in the range of 5 nN to 7 nN and, moreover, the replacement of hexagonal rings by pentagons or heptagons significantly changed the location of double bonds in the helicenes. The fracture analysis revealed two different fracture mechanisms that could be related to the configurations of double and single bonds located at the internal atomic chain. Simulations performed with and without van der Waals interactions between intramolecular atoms showed that these interactions played an important role only in the first deformation stage. PMID:26118679
Arabadjis, Dimitris; Rousopoulos, Panayiotis; Papaodysseus, Constantin; Panagopoulos, Michalis; Loumou, Panayiota; Theodoropoulos, Georgios
2012-01-01
A novel methodology is introduced here that exploits 2D images of arbitrary elastic body deformation instances, so as to quantify mechano-elastic characteristics that are deformation invariant. Determination of such characteristics allows for developing methods offering an image of the undeformed body. General assumptions about the mechano-elastic properties of the bodies are stated, which lead to two different approaches for obtaining bodies' deformation invariants. One was...
Modeling and Simulation of Grasping of Deformable Objects
DEFF Research Database (Denmark)
Fugl, Andreas Rune
2013-01-01
Automated robot solutions have for decades been increasing productivity around the world. They are attractive for being fast, accurate and able to work in dangerous and repetitive environments. In traditional applications the grasped object is kinematically attached to the Tool Center Point and assumed to rigidly follow. For a broad range of objects, material and force combinations, the rigid assumption holds very well. The reason is that the size of deformations is often relatively small. However for some application use-cases, elastic properties of grasped objects cannot be ignored. The purpose of this thesis is to address the modeling and simulation of deformable objects, as applied to robotic grasping and manipulation. The main contributions of this work are: An evaluation of 3D linear elasticity used for robot grasping as implemented by a Finite Difference Method supporting regular and adaptively refined grids, a stable and accurate non-linear 2D beam model supporting large deformations and difficult boundary effects, a method for the estimation of material properties and pose from depth and colour images, a method for the learning of Peg-in-Hole actions, an outline for Laying-Down actions as well a throughout evaluation of the accuracy of models under large deformations.
Thermomechanical Properties of TiNi Shape Memory Alloy
Tobushi, H.; Ikai, A.; Yamada, S; TANAKA, K; Lexcellent, C.
1996-01-01
The thermomechanical properties of shape memory effect and superelasticity due to the martensitic transformation and the R-phase transformation of TiNi shape memory alloy were investigated experimentally. The transformation Une, recovery stress and fatigue property due to both transformations were discussed for cyclic deformation. The thermomechanical properties due to the R-phase transformation were excellent for deformation with high cycles.
Computing layouts with deformable templates
Peng, Chihan
2014-07-27
In this paper, we tackle the problem of tiling a domain with a set of deformable templates. A valid solution to this problem completely covers the domain with templates such that the templates do not overlap. We generalize existing specialized solutions and formulate a general layout problem by modeling important constraints and admissible template deformations. Our main idea is to break the layout algorithm into two steps: a discrete step to lay out the approximate template positions and a continuous step to refine the template shapes. Our approach is suitable for a large class of applications, including floorplans, urban layouts, and arts and design. Copyright © ACM.
Cavity coalescence in superplastic deformation
Energy Technology Data Exchange (ETDEWEB)
Stowell, M.J.; Livesey, D.W.; Ridley, N.
1984-01-01
An analysis of the probability distribution function of particles randomly dispersed in a solid has been applied to cavitation during superplastic deformation and a method of predicting cavity coalescence developed. Cavity size distribution data were obtained from two microduplex nickel-silver alloys deformed superplastically to various extents at elevated temperature, and compared to theoretical predictions. Excellent agreement occurred for small void sizes but the model underestimated the number of voids in the largest size groups. It is argued that the discrepancy results from a combination of effects due to non-random cavity distributions and to enhanced growth rates and incomplete spheroidization of the largest cavities.
Deforming baryons into confining strings
Hartnoll, S A; Hartnoll, Sean A.; Portugues, Ruben
2004-01-01
We find explicit probe D3-brane solutions in the infrared of the Maldacena-Nunez background. The solutions describe deformed baryon vertices: q external quarks are separated in spacetime from the remaining N-q. As the separation is taken to infinity we recover known solutions describing infinite confining strings in ${\\mathcal{N}}=1$ gauge theory. We present results for the mass of finite confining strings as a function of length. We also find probe D2-brane solutions in a confining type IIA geometry, the reduction of a G_2 holonomy M theory background. The interpretation of these solutions as deformed baryons/confining strings is not as straightforward.
Fourth order deformed general relativity
Cuttell, Peter D
2014-01-01
Whenever the condition of anomaly freedom is imposed within the framework of effective approaches to loop quantum cosmology, one seems to conclude that a deformation of general covariance is required. Here, starting from a general deformation we regain an effective gravitational Lagrangian including terms up to fourth order in extrinsic curvature. We subsequently constrain the form of the corrections, and then investigate the conditions for the occurrence of a big bounce and the realisation of an inflationary era, in the presence of a perfect fluid or scalar field.
Near-surface deformation in polypropylene blends
Tang, Honxiang
Polypropylene blends with up to 20% rubber phase are known as thermoplastic polyolefin or TPO and have been widely used in the automotive industry in both painted and unpainted components. Poor scratch resistance and paint adhesion have been of great concern for TPO applications. The research described in this thesis has addressed both of these issues by studying the near-surface deformation under scratches in unpainted TPO, and the interfacial adhesion and deformation of painted TPO. A transmission electron microscopy approach has been developed to study the microstructure and microdeformation in this important class of engineering materials. It was observed that highly oriented near-surface material in injection-molded TPO plastically deformed by forming periodic shear bands under scratches. The material inside the shear band dilated as revealed by the difference in the angles between the shear band boundary and the rubber particles inside and outside the shear bands. The extent of material dilation inside the shear bands decreased with the distance from the free surface and increased with normal applied load. At high applied normal loads (>400 g), a significant amount of voiding caused by the debonding between the rubber phase and the PP matrix was observed. Talc particles were found to preferentially wet the rubber phase and this may prevent debonding between talc particles and the PP matrix as observed in talc-filled pure PP. The anisotropy in scratching behavior correlates with the anisotropy in mechanical properties. The morphology of the scratching deformation was found to be particularly sensitive to the near-surface structural anisotropy. A tensile cracking test was applied to quantitatively measure the interfacial adhesion between paint and TPO substrates. Interfacial structure between chlorinated polyolefin adhesion promoter and TPO substrate was studied by electron microscopy. The swelling of the rubber phase near the interface was observed, evidently arising from the interaction with the solvent in the paint and adhesion promoter. Diffusion of the rubber phase near the interface was also observed. Baking at high temperature enhanced both the swelling and interfacial diffusion of rubber phase. Paint adhesion was improved in TPO substrates with lower molecular weight PP homopolymer, which was ascribed to the enhanced interfacial diffusion.
Patterns of Alloy Deformation by Pulsed Pressure
Chebotnyagin, L. M.; Potapov, V. V.; Lopatin, V. V.
2015-06-01
Patterns of alloy deformation for optimization of a welding regime are studied by the method of modeling and deformation profiles providing high deformation quality are determined. A model of stepwise kinetics of the alloy deformation by pulsed pressure from the expanding plasma channel inside of a deformable cylinder is suggested. The model is based on the analogy between the acoustic and electromagnetic wave processes in long lines. The shock wave pattern of alloy deformation in the presence of multiple reflections of pulsed pressure waves in the gap plasma channel - cylinder wall and the influence of unloading waves from free surfaces are confirmed.
Representation Theory of Generalized Deformed Oscillator Algebras
Quesne, C
1997-01-01
The representation theory of the generalized deformed oscillator algebras (GDOA's) is developed. GDOA's are generated by the four operators ${1,a,a^{\\dag},N}$. Their commutators and Hermiticity properties are those of the boson oscillator algebra, except for $[a, a^{\\dag}]_q = G(N)$, where $[a,b]_q = a b - q b a$ and $G(N)$ is a Hermitian, analytic function. The unitary irreductible representations are obtained by means of a Casimir operator $C$ and the semi-positive operator $a^{\\dag} a$. They may belong to one out of four classes: bounded from below (BFB), bounded from above (BFA), finite-dimentional (FD), unbounded (UB). Some examples of these different types of unirreps are given.
Representation theory of generalized deformed oscillator algebras
Quesne, Christiane; Vansteenkiste, Nicolas
1997-01-01
The representation theory of the generalized deformed oscillator algebras (GDOA''s) is developed. GDOA''s are generated by the four operators {1, a, a , N}. Their commutators and Hermiticity properties are those of the boson oscillator algebra, except for [a, a ] q = G(N), where [a, b] q = ab - q ba and G(N) is a Hermitian, analytic function. The unitary irreductible representations are obtained by means of a Casimir operator C and the semi-positive operator a † a. They may belong to one out of four classes: bounded from below (BFB), bounded from above (BFA), finite-dimentional (FD), unbounded (UB). Some examples of these different types of unirreps are given.
Thorax deformity, joint hypermobility and anxiety disorder
International Nuclear Information System (INIS)
Objective was to evaluate the association between thorax deformities, panic disorder and joint hypermobility. The study includes 52 males diagnosed with thorax deformity, and 40 healthy male controls without thorax deformity, in Tatvan Bitlis and Isparta, Turkey. The study was carried out from 2004 to 2006. The teleradiographic and thoracic lateral images of the subjects were evaluated to obtain the Beighton scores; subjects psychiatric conditions were evaluated using the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-1), and the Hamilton Anxiety Scale (HAM-A) was applied in order to determine the anxiety levels. Both the subjects and controls were compared in sociodemographic, anxiety levels and joint mobility levels. In addition, males with joint hypermobility and thorax deformity were compared to the group with thorax deformity without joint hypermobility. A significant difference in HAM-A scores was found between the groups with thorax deformity and without. In addition, 21 subjects with thorax deformity met the joint hypermobility criteria in the group with thorax deformity and 7 subjects without thorax deformity met the joint hypermobility criteria in the group without thorax deformity, according to Beighton scoring. The Beighton score of subjects with thorax deformity were significantly different from those of the group without deformity. Additionally, anxiety scores of the males with thorax deformity and joint hypermobility were found higher than males with thorax deformity without joint hypermobility. Anxiety disorders, particularly panic disorder, have a significantly higher distribution in males subjects with thorax deformity compared to the healthy control group. In addition, the anxiety level of males with thorax deformity and joint hypermobility is higher than males with thorax deformity without joint hypermobility. (author)
UTILIZATION OF STEREOLOGY FOR QUANTITATIVE ANALYSIS OF PLASTIC DEFORMATION OF FORMING PIECES
Directory of Open Access Journals (Sweden)
Maroš Martinkovi?
2012-01-01
Full Text Available Mechanical working leads to final properties of forming pieces, which are affected by conditions of production technology. Utilization of stereology leads to the detail analysis of three-dimensional plastic deformed material structure by different forming technologies, e.g. forging, extruding, upsetting, metal spinning, drawing etc. The microstructure of cold drawing wires was analyzed. Grain boundaries orientation was measured on the parallel section of wire with a different degree of deformation and direct axis plastic deformation was evaluated in bulk formed part. The strain of probes on their sections was obtained using stereology by measurement of degree of grain boundary orientation which was converted to deformation using model of conversion of grain boundary orientation degree to deformation.
High temperature behavior of a deformed Fermi gas obeying interpolating statistics
Algin, Abdullah; 10.1103/PhysRevE.85.041123
2012-01-01
An outstanding idea originally introduced by Greenberg is to investigate whether there is equivalence between intermediate statistics, which may be different from anyonic statistics, and q-deformed particle algebra. Also, a model to be studied for addressing such an idea could possibly provide us some new consequences about the interactions of particles as well as their internal structures. Motivated mainly by this idea, in this work, we consider a q-deformed Fermi gas model whose statistical properties enable effectively us to study interpolating statistics. Starting with a generalized Fermi-Dirac distribution function, we derive several thermostatistical functions of a gas of these deformed fermions in the thermodynamical limit. We study the high temperature behavior of the system by analyzing the effects of q-deformation on the most important thermostatistical characteristics of the system such as the entropy, specific heat, and equation of state. It is shown that such a deformed fermion model in two and t...
Deformable Models for Eye Tracking
DEFF Research Database (Denmark)
Vester-Christensen, Martin; Leimberg, Denis
2005-01-01
A deformable template method for eye tracking on full face images is presented. The strengths of the method are that it is fast and retains accuracy independently of the resolution. We compare the me\\$\\backslash\\$-thod with a state of the art active contour approach, showing that the heuristic method is more accurate.
Diabolic points in deformation space
Energy Technology Data Exchange (ETDEWEB)
Chasman, R.R. (Argonne National Lab., IL (USA). Physics Div. Lawrence Berkeley Lab., CA (USA). Nuclear Science Div.); Ring, P. (Lawrence Berkeley Lab., CA (USA). Nuclear Science Div.)
1990-03-22
The occurrence of diabolic points in a realistic deformable nuclear single-particle potential is investigated. Several such points are explicitly identified using the Berry criterion. A general rule is given for finding other diabolic points. Experimental signatures of diabolic doublets are discussed. (orig.).
Diabolic points in deformation space
International Nuclear Information System (INIS)
The occurrence of diabolic points in a realistic deformable nuclear single-particle potential is investigated. Several such points are explicitly identified using the Berry criterion. A general rule is given for finding other diabolic points. Experimental signatures of diabolic doublets are discussed. (orig.)
Diabolic points in deformation space
Chasman, R. R.; Ring, P.
1990-03-01
The occurence of diabolic points in a realistic deformable nuclear single-particle potential is investigated. Several such points are explicitly identified using the Berry criterion. A general rule is given for finding other diabolic points. Experimental signatures of diabolic doublets are discussed.
Noncommutative gerbes and deformation quantization
Aschieri, Paolo; Bakovic, Igor; Jurco, Branislav; Schupp, Peter
2002-01-01
We define noncommutative gerbes using the language of star products. Quantized twisted Poisson structures are discussed as an explicit realization in the sense of deformation quantization. Our motivation is the noncommutative description of D-branes in the presence of topologically non-trivial background fields.
On deformations of Lagrangian fibrations
Matsushita, Daisuke
2009-01-01
Let X be an irreducible symplectic manifold and Def(X) the Kuranishi space. Assume that X admits a Lagrangian fibration. We prove that X can be deformed preserving a Lagrangian fibration. More precisely, there exists a smooth hypersurface H of Def(X) such that the restriction family over H admits a family of Lagrangian fibrations over H.
Patterns in heavily deformed metals
International Nuclear Information System (INIS)
Ductile metals can sustain very high levels of plastic strain without fracture. At low or intermediate temperatures (deformation regime dominated by crystallographic slip), deformation is accompanied by an increasing storage of dislocation density concomitant with a strength rise that can amount to more than two orders of magnitude. Dislocations accumulate in characteristic heterogeneous cellular patterns whose average size correlates with the interdislocation distance and with the inverse of the strength. The patterns do not merely shrink as deformation proceeds but suffer qualitative changes attested by a marked transition in work hardening behaviour. Although the starting cellular dislocation substructure, composed of thick, tangled walls is progressively substituted by a neat arrangement of two-dimensional sub-boundaries, the work hardening transition observed at large strains does not coincide with any sudden cell to subgrain substructural transition and its underlying substructural basis has not yet been unveiled. This and other unsolved questions about the substructures of heavily deformed metals will be addressed in the paper, namely the qualitative and quantitative observation of self-similarity of the substructures in a limited scale-range and its implications in the discussion on the physical process of substructure building. (orig.)
Effect of Cyclic Deformation on Magnetorheological Elastomers
Zhang, Wei; Gong, Xing-long; Sun, Tao-lin; Fan, Yan-ceng; Jiang, Wan-quan
2010-04-01
Fatigue properties of magnetorheological elastomer (MRE) samples were investigated based on cis-polybutadiene rubber by using a fatigue test machine. Three MRE samples with iron particles mass fraction of 60%, 70%, and 80% were fabricated, and their properties dependence of three strain amplitudes (50%, 75%, and 100%) were measured. The absolute magnetorheological (MR) effect, storage modulus, and loss modulus of MRE samples after fatigue were evaluated by a modified dynamic mechanical analyzer. The results revealed that MR effect, storage modulus, and loss modulus of MREs containing 80% iron particles depended strongly on the strain amplitudes and the number of cycles, while storage modulus and loss modulus of MREs containing 70% iron particles also depended on the strain amplitudes and the number of cycles but not as strongly as sample which contains 80% iron particles, but the properties of MREs containing 60% iron particles after cyclic deformation were almost independent of the fatigued conditions. In order to investigate the fatigue mechanism of MREs, the sample was carried out with a quasi-static tensile testing and its surface morphology during testing was observed in situ by scanning electron microscopy.
Wreath products, nilpotent orbits and symplectic deformations
Fu, Baohua
2006-01-01
We recover a 4-dimensional wreath product X as a transversal slice to a nilpotent orbit in sp_6. By using deformations of Springer resolutions, we construct a symplectic deformation of symplectic resolutions of X.
2-D geometrical analysis of deformation
International Nuclear Information System (INIS)
Engineering structures such as dams, bridges, high rise buildings, etc. are subject to deformation. Deformation survey is therefore necessary to determine the magnitude and direction of such movements for the purpose of safety assessment. In this study, a strategy for two-step analyses for deformation survey rising the two dimensional (2-D) geodetic method has been developed, consisting of independent least squares estimation (LSE) of each epoch followed by deformation detection. Important aspects on LSE include global and local testing. In deformation detection, the following aspects were implemented; datum definition by the user. determination of stable datum points, geometrical analysis of deformation and graphic presentation. The developed strategy has been implemented in three computer programs, COMPUT, DEFORM and STRANS. Tests carried out with simulated and known data show that the developed strategy and programs are applicable for 2-D geometrical detection of deformation. (Author)
International Nuclear Information System (INIS)
This literature survey is focused upon relations between stress change, deformation and transmissivity for fractures and deformation zones and aims at compiling and commenting on relevant information and references with focus on data from in situ investigations. Main issues to investigate are: - Impact of normal stress change and deformation on transmissivity, for fractures and deformation zones. - Impact of shear stress and displacement on transmissivity, for fractures and deformation zones for different normal load conditions. Considering the line of research within the area, the following steps in the development can be identified. During the 1970's and 1980's, the fundamentals of rock joint deformation were investigated and identification and description of mechanisms were made in the laboratory. In the 1990's, coupling of stress-flow properties of rock joints were made using hydraulic testing to identify and describe the mechanisms in the field. Both individual fractures and deformation zones were of interest. In situ investigations have also been the topic of interest the last ten years. Further identification and description of mechanisms in the field have been made including investigation and description of system of fractures, different types of fractures (interlocked/mated or mismatched/unmated) and how this is coupled to the hydromechanical behavior. In this report, data from in situ investigations are compiled and the parameters considered to be important to link fracture deformation and transmissivity are normal stiffness, kn and hydraulic aperture, bh. All data except for those from one site originate from investigations performed in granitic rock. Normal stiffness, kn, and hydraulic aperture, bh, are correlated, even though data are scattered. In general, the largest variation is seen for small hydraulic apertures and high normal stiffness. The increasing number of contact points (areas) and fracture filling are likely explanations. To conclude, impact of normal stress change and deformation on transmissivity could be described based on data from in situ investigations. The results shown in this compilation present a possibility to estimate normal stiffness, kn and hydraulic aperture, bh based on storage coefficient, S, and transmissivity, T, from hydraulic interference tests performed in the area of interest. Concerning the impact of shear stress and displacement on transmissivity, no detailed field data was found. This is in line with the comment by Guglielmi et al. where the authors express an urgent need to develop in situ measurements of both normal and shear displacements. An important future issue is therefore better descriptions of the dependency between shear displacement and transmissivity in the field. Further research within the area of hydromechanical coupling where geology, hydrogeology and geomechanics meet is likely to increase the understanding of all these areas