WorldWideScience

Sample records for stacking fault formation

  1. Stacking fault tetrahedra formation in the neighbourhood of grain boundaries

    CERN Document Server

    Samaras, M; Van Swygenhoven, H; Victoria, M

    2003-01-01

    Large scale molecular dynamics computer simulations are performed to study the role of the grain boundary (GB) during the cascade evolution in irradiated nanocrystalline Ni. At all primary knock-on atom (PKA) energies in cascades near GBs, the damage produced after cooling down is vacancy dominated. Truncated stacking fault tetrahedra (TSFTs) are easily formed at 10 keV and higher PKA energies. At the higher energies a complex partial dislocation network forms, consisting of TSFTs. The GB acts as an interstitial sink without undergoing major structural changes.

  2. Formation of stacking faults and the screw dislocation-driven growth: a case study of aluminum nitride nanowires.

    Science.gov (United States)

    Meng, Fei; Estruga, Marc; Forticaux, Audrey; Morin, Stephen A; Wu, Qiang; Hu, Zheng; Jin, Song

    2013-12-23

    Stacking faults are an important class of crystal defects commonly observed in nanostructures of close packed crystal structures. They can bridge the transition between hexagonal wurtzite (WZ) and cubic zinc blende (ZB) phases, with the most known example represented by the "nanowire (NW) twinning superlattice". Understanding the formation mechanisms of stacking faults is crucial to better control them and thus enhance the capability of tailoring physical properties of nanomaterials through defect engineering. Here we provide a different perspective to the formation of stacking faults associated with the screw dislocation-driven growth mechanism of nanomaterials. With the use of NWs of WZ aluminum nitride (AlN) grown by a high-temperature nitridation method as the model system, dislocation-driven growth was first confirmed by transmission electron microscopy (TEM). Meanwhile numerous stacking faults and associated partial dislocations were also observed and identified to be the Type I stacking faults and the Frank partial dislocations, respectively, using high-resolution TEM. In contrast, AlN NWs obtained by rapid quenching after growth displayed no stacking faults or partial dislocations; instead many of them had voids that were associated with the dislocation-driven growth. On the basis of these observations, we suggest a formation mechanism of stacking faults that originate from dislocation voids during the cooling process in the syntheses. Similar stacking fault features were also observed in other NWs with WZ structure, such as cadmium sulfide (CdS) and zinc oxide (ZnO).

  3. Basic criteria for formation of growth twins in high stacking fault energy metals

    International Nuclear Information System (INIS)

    Yu, K. Y.; Zhang, X.; Bufford, D.; Chen, Y.; Liu, Y.; Wang, H.

    2013-01-01

    Nanotwinned metals received significant interest lately as twin boundaries may enable simultaneous enhancement of strength, ductility, thermal stability, and radiation tolerance. However, nanotwins have been the privilege of metals with low-to-intermediate stacking fault energy (SFE). Recent scattered studies show that nanotwins could be introduced into high SFE metals, such as Al. In this paper, we examine several sputter-deposited, (111) textured Ag/Al, Cu/Ni, and Cu/Fe multilayers, wherein growth twins were observed in Al, Ni, and face-centered cubic (fcc) Fe. The comparisons lead to two important design criteria that dictate the introduction of growth twins in high SFE metals. The validity of these criteria was then examined in Ag/Ni multilayers. Furthermore, another twin formation mechanism in high SFE metals was discovered in Ag/Ni system

  4. Anisotropic formation and distribution of stacking faults in II-VI semiconductor nanorods.

    Science.gov (United States)

    Hughes, Steven M; Alivisatos, A Paul

    2013-01-09

    Nanocrystals of cadmium selenide exhibit a form of polytypism with stable forms in both the wurtzite and zinc blende crystal structures. As a result, wurtzite nanorods of cadmium selenide tend to form stacking faults of zinc blende along the c-axis. These faults were found to preferentially form during the growth of the (001) face, which accounts for 40% of the rod's total length. Since II-VI semiconductor nanorods lack inversion symmetry along the c-axis of the particle, the two ends of the nanorod may be identified by this anisotropic distribution of faults.

  5. Stress-induced formation mechanism of stacking fault tetrahedra in nano-cutting of single crystal copper

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Quanlong [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China); Center for Precision Engineering, Harbin Institute of Technology, Harbin 150001 (China); Bai, Qingshun [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China); Chen, Jiaxuan, E-mail: wangquanlong0@hit.edu.cn [Center for Precision Engineering, Harbin Institute of Technology, Harbin 150001 (China); Guo, Yongbo [Center for Precision Engineering, Harbin Institute of Technology, Harbin 150001 (China); Xie, Wenkun [School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001 (China); Center for Precision Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2015-11-15

    Graphical abstract: In this paper, molecular dynamics simulation is performed to study the distribution of dislocation defects and local atomic crystal structure of single crystal copper. The stress distribution is investigated which is calculated by virial stress and analyzed by static pressure. The results are shown in (a)–(d). It is indicated that the compressive stress mainly spreads over the shear-slip zone, and the tensile stress is consisted in flank friction zone, shown in (a). The high tensile stress in subsurface is the source of stress, shown in (b). By the driven action of the stress source, the initial stair-rod dislocation nucleates. Then the dislocation climbs along four {1 1 1} planes under the stress driven action, shown in (d). Finally, the SFT is formed by the interaction of the compressive stress and the tensile stress which come from the shear-slip zone and friction zone, respectively. Besides, stair-rod dislocation, stacking faults and dislocation loop are also nucleated in the subsurface, shown in (c). Dislocation distribution, local atomic crystal structure state and stress-induced formation process of SFT by atomic. - Highlights: • A novel defect structure “stress-induced stacking fault tetrahedra” is revealed. • Atomic structural evolution and stress state distribution of the SFT are studied. • The stress-induced formation mechanism of the SFT is proposed. - Abstract: Stacking fault tetrahedra commonly existed in subsurface of deformed face center cubic metals, has great influence on machining precision and surface roughness in nano-cutting. Here we report, a stacking fault tetrahedra is formed in subsurface of workpiece during nano-cutting. The variation of cutting force and subsurface defects distribution are studied by using molecular dynamics simulation. The stress distribution is investigated which is calculated by virial stress and analyzed by static compression. The result shows that the cutting force has a rapidly

  6. Stress-induced formation mechanism of stacking fault tetrahedra in nano-cutting of single crystal copper

    International Nuclear Information System (INIS)

    Wang, Quanlong; Bai, Qingshun; Chen, Jiaxuan; Guo, Yongbo; Xie, Wenkun

    2015-01-01

    Graphical abstract: In this paper, molecular dynamics simulation is performed to study the distribution of dislocation defects and local atomic crystal structure of single crystal copper. The stress distribution is investigated which is calculated by virial stress and analyzed by static pressure. The results are shown in (a)–(d). It is indicated that the compressive stress mainly spreads over the shear-slip zone, and the tensile stress is consisted in flank friction zone, shown in (a). The high tensile stress in subsurface is the source of stress, shown in (b). By the driven action of the stress source, the initial stair-rod dislocation nucleates. Then the dislocation climbs along four {1 1 1} planes under the stress driven action, shown in (d). Finally, the SFT is formed by the interaction of the compressive stress and the tensile stress which come from the shear-slip zone and friction zone, respectively. Besides, stair-rod dislocation, stacking faults and dislocation loop are also nucleated in the subsurface, shown in (c). Dislocation distribution, local atomic crystal structure state and stress-induced formation process of SFT by atomic. - Highlights: • A novel defect structure “stress-induced stacking fault tetrahedra” is revealed. • Atomic structural evolution and stress state distribution of the SFT are studied. • The stress-induced formation mechanism of the SFT is proposed. - Abstract: Stacking fault tetrahedra commonly existed in subsurface of deformed face center cubic metals, has great influence on machining precision and surface roughness in nano-cutting. Here we report, a stacking fault tetrahedra is formed in subsurface of workpiece during nano-cutting. The variation of cutting force and subsurface defects distribution are studied by using molecular dynamics simulation. The stress distribution is investigated which is calculated by virial stress and analyzed by static compression. The result shows that the cutting force has a rapidly

  7. Participation of oxygen and carbon in formation of oxidation-induced stacking faults in monocrystalline silicon

    Directory of Open Access Journals (Sweden)

    Иван Федорович Червоный

    2015-11-01

    Full Text Available It is experimentally established, that density of oxidation-induced stacking faults (OISF in the boron doped monocrystalline silicon plates, that above, than it is more relation of oxygen atoms concentration to carbon atoms concentration in them.On research results of geometry of OISF rings in the different sections of single-crystal geometry of areas is reconstructed with their different closeness. At adjustment of the growing modes of single-crystals of silicon the increase of output of suitable product is observed

  8. Atomistically determined phase-field modeling of dislocation dissociation, stacking fault formation, dislocation slip, and reactions in fcc systems

    Science.gov (United States)

    Rezaei Mianroodi, Jaber; Svendsen, Bob

    2015-04-01

    The purpose of the current work is the development of a phase field model for dislocation dissociation, slip and stacking fault formation in single crystals amenable to determination via atomistic or ab initio methods in the spirit of computational material design. The current approach is based in particular on periodic microelasticity (Wang and Jin, 2001; Bulatov and Cai, 2006; Wang and Li, 2010) to model the strongly non-local elastic interaction of dislocation lines via their (residual) strain fields. These strain fields depend in turn on phase fields which are used to parameterize the energy stored in dislocation lines and stacking faults. This energy storage is modeled here with the help of the "interface" energy concept and model of Cahn and Hilliard (1958) (see also Allen and Cahn, 1979; Wang and Li, 2010). In particular, the "homogeneous" part of this energy is related to the "rigid" (i.e., purely translational) part of the displacement of atoms across the slip plane, while the "gradient" part accounts for energy storage in those regions near the slip plane where atomic displacements deviate from being rigid, e.g., in the dislocation core. Via the attendant global energy scaling, the interface energy model facilitates an atomistic determination of the entire phase field energy as an optimal approximation of the (exact) atomistic energy; no adjustable parameters remain. For simplicity, an interatomic potential and molecular statics are employed for this purpose here; alternatively, ab initio (i.e., DFT-based) methods can be used. To illustrate the current approach, it is applied to determine the phase field free energy for fcc aluminum and copper. The identified models are then applied to modeling of dislocation dissociation, stacking fault formation, glide and dislocation reactions in these materials. As well, the tensile loading of a dislocation loop is considered. In the process, the current thermodynamic picture is compared with the classical mechanical

  9. On the "stacking fault" in copper

    NARCIS (Netherlands)

    Fransens, J.R.; Pleiter, F

    2003-01-01

    The results of a perturbed gamma-gamma angular correlations experiment on In-111 implanted into a properly cut single crystal of copper show that the defect known in the literature as "stacking fault" is not a planar faulted loop but a stacking fault tetrahedron with a size of 10-50 Angstrom.

  10. New horizon for high performance Mg-based biomaterial with uniform degradation behavior: Formation of stacking faults.

    Science.gov (United States)

    Zhang, Jinghuai; Xu, Chi; Jing, Yongbin; Lv, Shuhui; Liu, Shujuan; Fang, Daqing; Zhuang, Jinpeng; Zhang, Milin; Wu, Ruizhi

    2015-09-09

    Designing the new microstructure is an effective way to accelerate the biomedical application of magnesium (Mg) alloys. In this study, a novel Mg-8Er-1Zn alloy with profuse nano-spaced basal plane stacking faults (SFs) was prepared by combined processes of direct-chill semi-continuous casting, heat-treatment and hot-extrusion. The formation of SFs made the alloy possess outstanding comprehensive performance as the biodegradable implant material. The ultimate tensile strength (UTS: 318 MPa), tensile yield strength (TYS: 207 MPa) and elongation (21%) of the alloy with SFs were superior to those of most reported degradable Mg-based alloys. This new alloy showed acceptable biotoxicity and degradation rate (0.34 mm/year), and the latter could be further slowed down through optimizing the microstructure. Most amazing of all, the uniquely uniform in vitro/vivo corrosion behavior was obtained due to the formation of SFs. Accordingly we proposed an original corrosion mechanism for the novel Mg alloy with SFs. The present study opens a new horizon for developing new Mg-based biomaterials with highly desirable performances.

  11. Density of oxidation-induced stacking faults in damaged silicon

    NARCIS (Netherlands)

    Kuper, F.G.; Hosson, J.Th.M. De; Verwey, J.F.

    1986-01-01

    A model for the relation between density and length of oxidation-induced stacking faults on damaged silicon surfaces is proposed, based on interactions of stacking faults with dislocations and neighboring stacking faults. The model agrees with experiments.

  12. In situ monitoring of stacking fault formation and its carrier lifetime mediation in p-type 4H-SiC

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Bin, E-mail: chenbinmse@gmail.com; Chen, Jun; Yao, Yuanzhao; Sekiguchi, Takashi [National Institute for Materials Science, Tsukuba, Ibaraki 305-0044 (Japan); Matsuhata, Hirofumi; Okumura, Hajime [National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568 (Japan)

    2014-07-28

    Using the fine control of an electron beam (e-beam) in scanning electron microscopy with the capabilities of both electrical and optical imaging, the stacking fault (SF) formation together with its tuning of carrier lifetime was in situ monitored and investigated in p-type 4H-SiC homoepitaxial films. The SFs were formed through engineering basal plane dislocations with the energy supplied by the e-beam. The e-beam intensity required for the SF formation in the p-type films was ∼100 times higher than that in the n-type ones. The SFs reduced the minority-carrier lifetime in the p-type films, which was opposite to that observed in the n-type case. The reason for the peculiar SF behavior in the p-type 4H-SiC is discussed with the cathodoluminescence results.

  13. Effect of stacking faults on the magnetocrystalline anisotropy of hcp Co: a first-principles study.

    Science.gov (United States)

    Aas, C J; Szunyogh, L; Evans, R F L; Chantrell, R W

    2013-07-24

    In terms of the fully relativistic screened Korringa-Kohn-Rostoker method we investigate the effect of stacking faults on the magnetic properties of hexagonal close-packed (hcp) cobalt. In particular, we consider the formation energy and the effect on the magnetocrystalline anisotropy energy (MAE) of four different stacking faults in hcp cobalt-an intrinsic growth fault, an intrinsic deformation fault, an extrinsic fault and a twin-like fault. We find that the intrinsic growth fault has the lowest formation energy, in good agreement with previous first-principles calculations. With the exception of the intrinsic deformation fault which has a positive impact on the MAE, we find that the presence of a stacking fault generally reduces the MAE of bulk Co. Finally, we consider a pair of intrinsic growth faults and find that their effect on the MAE is not additive, but synergic.

  14. Displacive phase transformations and generalized stacking faults

    Czech Academy of Sciences Publication Activity Database

    Paidar, Václav; Ostapovets, Andriy; Duparc, O. H.; Khalfallah, O.

    2012-01-01

    Roč. 122, č. 3 (2012), s. 490-492 ISSN 0587-4246. [International Symposium on Physics of Materials, ISPMA /12./. Praha, 04.09.2011-08.09.2011] R&D Projects: GA AV ČR IAA100100920 Institutional research plan: CEZ:AV0Z10100520 Keywords : ab-initio calculations * close-packed structures * generalized stacking faults * homogeneous deformation * lattice deformation * many-body potentials Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.531, year: 2012

  15. Generalized stacking fault energies of alloys.

    Science.gov (United States)

    Li, Wei; Lu, Song; Hu, Qing-Miao; Kwon, Se Kyun; Johansson, Börje; Vitos, Levente

    2014-07-02

    The generalized stacking fault energy (γ surface) provides fundamental physics for understanding the plastic deformation mechanisms. Using the ab initio exact muffin-tin orbitals method in combination with the coherent potential approximation, we calculate the γ surface for the disordered Cu-Al, Cu-Zn, Cu-Ga, Cu-Ni, Pd-Ag and Pd-Au alloys. Studying the effect of segregation of the solute to the stacking fault planes shows that only the local chemical composition affects the γ surface. The calculated alloying trends are discussed using the electronic band structure of the base and distorted alloys.Based on our γ surface results, we demonstrate that the previous revealed 'universal scaling law' between the intrinsic energy barriers (IEBs) is well obeyed in random solid solutions. This greatly simplifies the calculations of the twinning measure parameters or the critical twinning stress. Adopting two twinnability measure parameters derived from the IEBs, we find that in binary Cu alloys, Al, Zn and Ga increase the twinnability, while Ni decreases it. Aluminum and gallium yield similar effects on the twinnability.

  16. Crystallite size effects in stacking faulted nickel hydroxide and its electrochemical behaviour

    International Nuclear Information System (INIS)

    Ramesh, T.N.

    2009-01-01

    β-Nickel hydroxide comprises a long range periodic arrangement of atoms with a stacking sequence of AC AC AC-having an ideal composition Ni(OH) 2 . Variation in the preparative conditions can lead to the changes in the stacking sequence (AC AC BA CB AC AC or AC AC AB AC AC). This type of variation in stacking sequence can result in the formation of stacking fault in nickel hydroxide. The stability of the stacking fault depends on the free energy content of the sample. Stacking faults in nickel hydroxide is essential for better electrochemical activity. Also there are reports correlating particle size to the better electrochemical activity. Here we present the effect of crystallite size on the stacking faulted nickel hydroxide samples. The electrochemical performance of stacking faulted nickel hydroxide with small crystallite size exchanges 0.8e/Ni, while the samples with larger crystallite size exchange 0.4e/Ni. Hence a right combination of crystallite size and stacking fault content has to be controlled for good electrochemical activity of nickel hydroxide

  17. Stacking faults and microstructural parameters in non-mulberry silk ...

    Indian Academy of Sciences (India)

    rameters like crystal size (〈N〉), lattice strain (g) and stacking faults in polymer materials ... metal oxide compounds, but may be inadequate for describing diffraction patterns .... Further, with these model parameters for individual Bragg reflec-.

  18. Formation of stacking faults and misfit dislocations during Zn diffusion-enhanced intermixing of a GaInAsP/InP heterostructure

    International Nuclear Information System (INIS)

    Park, H.H.; Nam, E.S.; Lee, Y.T.; Lee, E.H.; Lee, J.Y.; Kwon, O.

    1991-01-01

    In this paper the microstructural degradation of a lattice-matched Ga 0.28 In 0.72 As 0.61 P 0.39 /InP heterointerface during atomic intermixing induced by Zn diffusion are investigated using high-resolution transmission electron microscopy and Auger electron spectroscopy. The localized interfacial stress caused by intermixing appears to create stacking faults in the Ga-mixed Inp substrate, and dislocation tangles in the In-mixed GaInAsP layer. The results are attributed to the contrasted effect of tensile and compressive stresses upon the nucleation of partial dislocations from both sides of the intermixed interface. A qualitative model is proposed for the homogeneous nucleation of misfit dislocations from the locally stressed interface

  19. Calculated stacking-fault energies of elemental metals

    DEFF Research Database (Denmark)

    Rosengaard, N. M.; Skriver, Hans Lomholt

    1993-01-01

    -sphere approximations. The results are in excellent agreement with recent layer Korringa-Kohn-Rostoker Green's-function calculations where stacking-fault energies for Ni, Cu, Rh, Pd, Ag, Ir, and Au were found by means of the the so-called force theorem. We find that the self-consistent fault energies for all the metals...

  20. Temperature dependence of stacking faults in catalyst-free GaAs nanopillars.

    Science.gov (United States)

    Shapiro, Joshua N; Lin, Andrew; Ratsch, Christian; Huffaker, D L

    2013-11-29

    Impressive opto-electronic devices and transistors have recently been fabricated from GaAs nanopillars grown by catalyst-free selective-area epitaxy, but this growth technique has always resulted in high densities of stacking faults. A stacking fault occurs when atoms on the growing (111) surface occupy the sites of a hexagonal-close-pack (hcp) lattice instead of the normal face-centered-cubic (fcc) lattice sites. When stacking faults occur consecutively, the crystal structure is locally wurtzite instead of zinc-blende, and the resulting band offsets are known to negatively impact device performance. Here we present experimental and theoretical evidence that indicate stacking fault formation is related to the size of the critical nucleus, which is temperature dependent. The difference in energy between the hcp and fcc orientation of small nuclei is computed using density-function theory. The minimum energy difference of 0.22 eV is calculated for a nucleus with 21 atoms, so the population of nuclei in the hcp orientation is expected to decrease as the nucleus grows larger. The experiment shows that stacking fault occurrence is dramatically reduced from 22% to 3% by raising the growth temperature from 730 to 790 ° C. These data are interpreted using classical nucleation theory which dictates a larger critical nucleus at higher growth temperature.

  1. Stacking Faults and Mechanical Behavior beyond the Elastic Limit of an Imidazole-Based Metal Organic Framework: ZIF-8.

    Science.gov (United States)

    Hegde, Vinay I; Tan, Jin-Chong; Waghmare, Umesh V; Cheetham, Anthony K

    2013-10-17

    We determine the nonlinear mechanical behavior of a prototypical zeolitic imidazolate framework (ZIF-8) along two modes of mechanical failure in response to tensile and shear forces using first-principles simulations. Our generalized stacking fault energy surface reveals an intrinsic stacking fault of surprisingly low energy comparable to that in copper, though the energy barrier associated with its formation is much higher. The lack of vibrational spectroscopic evidence for such faults in experiments can be explained with the structural instability of the barrier state to form a denser and disordered state of ZIF-8 seen in our analysis, that is, large shear leads to its amorphization rather than formation of faults.

  2. Stacking faults and phase changes in Mg-doped InGaN grown on Si

    International Nuclear Information System (INIS)

    Liliental-Weber, Zuzanna; Yu, Kin M.; Reichertz, Lothar A.; Ager, Joel W.; Walukiewicz, Wladek; Schaff, William J.; Hawkridge, Michael E.

    2009-01-01

    We report evidence for the role of Mg in the formation of basal stacking faults and a phase transition in In x Ga 1-x N layers doped with Mg grown by molecular beam epitaxy on Si(111) substrates with AlN buffer layers. Several samples with varying In content between x∝0.1 and x∝0.3 are examined by transmission electron microscopy and other techniques. High densities of basal stacking faults are observed in the central region of the InGaN layer away from the substrate or layer surface, but at varying depths within this region. Selected area diffraction patterns show that while the InGaN layer is initially in the wurtzite phase (and of good quality) AlN buffer layer, there is a change to the zinc blende phase in the upper part of the InGaN layer. SIMS measurements show that the Mg concentration drops from a maximum to a steady concentration coinciding with the presence of the basal stacking faults. There is little change in In or Ga concentrations in the same area. High-resolution electron microscopy from the area of the stacking faults confirms that the change to the cubic phase is abrupt across one such fault. These results indicate that Mg plays a role in the formation of stacking faults and the phase change observed in In x Ga 1-x N alloys. We also consider the role of In in the formation of these defects. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. Electronic structure of the rotation twin stacking fault in β-ZnS

    International Nuclear Information System (INIS)

    Northrup, J.E.; Cohen, M.L.

    1981-01-01

    The electronic structure of the rotation twin stacking fault in β-ZnS is calculated with the self-consistent pseudopotential method. The stacking fault creates a potential barrier of approx.0.07 eV and induces the localization of stacking-fault resonances near the top of the valence band. Stacking-fault states are also predicted to exist in the various gaps in the projected valence-band structure

  4. Radiation Induced Removal of Stacking Faults in Quenched Aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Bergenlid, U

    1965-12-15

    The effect of neutron irradiation on specimens of quenched aluminium containing Frank sessile dislocation loops has been studied by means of electron microscopy. The Frank loops were found to trans. form into perfect loops at doses less than 10{sup 17} nvt. A possible reason for the removal of the stacking faults is the displacement of a number of atoms at the faults, leading to the passage of a Shockley partial. Unfaulting induced by stress fields from dislocations, released during the irradiation, can also be important.

  5. Radiation Induced Removal of Stacking Faults in Quenched Aluminium

    International Nuclear Information System (INIS)

    Bergenlid, U.

    1965-12-01

    The effect of neutron irradiation on specimens of quenched aluminium containing Frank sessile dislocation loops has been studied by means of electron microscopy. The Frank loops were found to trans. form into perfect loops at doses less than 10 17 nvt. A possible reason for the removal of the stacking faults is the displacement of a number of atoms at the faults, leading to the passage of a Shockley partial. Unfaulting induced by stress fields from dislocations, released during the irradiation, can also be important

  6. Thermodynamic modeling of the stacking fault energy of austenitic steels

    International Nuclear Information System (INIS)

    Curtze, S.; Kuokkala, V.-T.; Oikari, A.; Talonen, J.; Haenninen, H.

    2011-01-01

    The stacking fault energies (SFE) of 10 austenitic steels were determined in the temperature range 50 ≤ T ≤ 600 K by thermodynamic modeling of the Fe-Cr-Ni-Mn-Al-Si-Cu-C-N system using a modified Olson and Cohen modeling approach (Olson GB, Cohen M. Metall Trans 1976;7A:1897 ). The applied model accounts for each element's contribution to the Gibbs energy, the first-order excess free energies, magnetic contributions and the effect of interstitial nitrogen. Experimental SFE values from X-ray diffraction measurements were used for comparison. The effect of SFE on deformation mechanisms was also studied by electron backscatter diffraction.

  7. Stacking fault-mediated ultrastrong nanocrystalline Ti thin films

    Science.gov (United States)

    Wu, K.; Zhang, J. Y.; Li, G.; Wang, Y. Q.; Cui, J. C.; Liu, G.; Sun, J.

    2017-11-01

    In this work, we prepared nanocrystalline (NC) Ti thin films with abundant stacking faults (SFs), which were created via partial dislocations emitted from grain boundaries and which were insensitive to grain sizes. By employing the nanoindentation test, we investigated the effects of SFs and grain sizes on the strength of NC Ti films at room temperature. The high density of SFs significantly strengthens NC Ti films, via dislocation-SF interactions associated with the reported highest Hall-Petch slope of ˜20 GPa nm1/2, to an ultrahigh strength of ˜4.4 GPa, approaching ˜50% of its ideal strength.

  8. Atomic-scale details of dislocation-stacking fault tetrahedra interaction

    International Nuclear Information System (INIS)

    Osetsky, Yu. N.; Stoller, R.E.; Rodney, D.; Bacon, D.J.

    2005-01-01

    Stacking fault tetrahedra (SFTs) are formed during irradiation of f.c.c. metals and alloys with low stacking fault energy. The high number density of SFTs observed suggests that they should contribute to radiation-induced hardening and, therefore, be taken into account when estimating mechanical property changes of irradiated materials. Key issue is to describe the interaction between a moving dislocation and an individual SFT, which is characterized by a small physical scale of about 100 nm. In this paper we present results of an atomistic simulation of edge and screw dislocations interacting with small SFTs at different temperatures and strain rates and present mechanisms which can explain the formation of defect-free channels observed experimentally

  9. Stacking fault growth of FCC crystal: The Monte-Carlo simulation approach

    International Nuclear Information System (INIS)

    Jian Jianmin; Ming Naiben

    1988-03-01

    The Monte-Carlo method has been used to simulate the growth of the FCC (111) crystal surface, on which is presented the outcrop of a stacking fault. The comparison of the growth rates has been made between the stacking fault containing surface and the perfect surface. The successive growth stages have been simulated. It is concluded that the outcrop of stacking fault on the crystal surface can act as a self-perpetuating step generating source. (author). 7 refs, 3 figs

  10. Stacking fault tetrahedron induced plasticity in copper single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Liang, E-mail: lz592@uowmail.edu.au [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522 (Australia); Lu, Cheng, E-mail: chenglu@uow.edu.au [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522 (Australia); Tieu, Kiet; Su, Lihong; Zhao, Xing [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, Wollongong, NSW 2522 (Australia); Pei, Linqing [Department of Mechanical Engineering, Chongqing University, Chongqing 400044 (China)

    2017-01-05

    Stacking fault tetrahedron (SFT) is the most common type of vacancy clustered defects in fcc metals and alloys, and can play an important role in the mechanical properties of metallic materials. In this study, molecular dynamics (MD) simulations were carried out to investigate the incipience of plasticity and the underlying atomic mechanisms in copper single crystals with SFT. Different deformation mechanisms of SFT were reported due to the crystal orientations and loading directions (compression and tension). The results showed that the incipient plasticity in crystals with SFT resulted from the heterogeneous dislocation nucleation from SFT, so the stress required for plastic deformation was less than that needed for perfect single crystals. Three crystal orientations ([1 0 0], [1 1 0] and [1 1 1]) were specified in this study because they can represent most of the typical deformation mechanisms of SFT. MD simulations revealed that the structural transformation of SFT was frequent under the applied loading; a metastable SFT structure and the collapse of SFT were usually observed. The structural transformation resulted in a different reduction of yield stress in compression and tension, and also caused a decreased or reversed compression/tension asymmetry. Compressive stress can result in the unfaulting of Frank loop in some crystal orientations. According to the elastic theory of dislocation, the process of unfaulting was closely related to the size of the dislocation loop and the stacking fault energy.

  11. Evolution of stacking fault tetrahedral and work hardening effect in copper single crystals

    Science.gov (United States)

    Liu, Hai Tao; Zhu, Xiu Fu; Sun, Ya Zhou; Xie, Wen Kun

    2017-11-01

    Stacking fault tetrahedral (SFT), generated in machining of copper single crystal as one type of subsurface defects, has significant influence on the performance of workpiece. In this study, molecular dynamics (MD) simulation is used to investigate the evolution of stacking fault tetrahedral in nano-cutting of copper single crystal. The result shows that SFT is nucleated at the intersection of differently oriented stacking fault (SF) planes and SFT evolves from the preform only containing incomplete surfaces into a solid defect. The evolution of SFT contains several stress fluctuations until the complete formation. Nano-indentation simulation is then employed on the machined workpiece from nano-cutting, through which the interaction between SFT and later-formed dislocations in subsurface is studied. In the meanwhile, force-depth curves obtained from nano-indentation on pristine and machined workpieces are compared to analyze the mechanical properties. By simulation of nano-cutting and nano-indentation, it is verified that SFT is a reason of the work hardening effect.

  12. Strain-Driven Stacking Faults in CdSe/CdS Core/Shell Nanorods.

    Science.gov (United States)

    Demortière, Arnaud; Leonard, Donovan N; Petkov, Valeri; Chapman, Karena; Chattopadhyay, Soma; She, Chunxing; Cullen, David A; Shibata, Tomohiro; Pelton, Matthew; Shevchenko, Elena V

    2018-04-19

    Colloidal semiconductor nanocrystals are commonly grown with a shell of a second semiconductor material to obtain desired physical properties, such as increased photoluminescence quantum yield. However, the growth of a lattice-mismatched shell results in strain within the nanocrystal, and this strain has the potential to produce crystalline defects. Here, we study CdSe/CdS core/shell nanorods as a model system to investigate the influence of core size and shape on the formation of stacking faults in the nanocrystal. Using a combination of high-angle annular dark-field scanning transmission electron microscopy and pair-distribution-function analysis of synchrotron X-ray scattering, we show that growth of the CdS shell on smaller, spherical CdSe cores results in relatively small strain and few stacking faults. By contrast, growth of the shell on larger, prolate spheroidal cores leads to significant strain in the CdS lattice, resulting in a high density of stacking faults.

  13. Mesoscale models for stacking faults, deformation twins and martensitic transformations: Linking atomistics to continuum

    Science.gov (United States)

    Kibey, Sandeep A.

    We present a hierarchical approach that spans multiple length scales to describe defect formation---in particular, formation of stacking faults (SFs) and deformation twins---in fcc crystals. We link the energy pathways (calculated here via ab initio density functional theory, DFT) associated with formation of stacking faults and twins to corresponding heterogeneous defect nucleation models (described through mesoscale dislocation mechanics). Through the generalized Peieirls-Nabarro model, we first correlate the width of intrinsic SFs in fcc alloy systems to their nucleation pathways called generalized stacking fault energies (GSFE). We then establish a qualitative dependence of twinning tendency in fee metals and alloys---specifically, in pure Cu and dilute Cu-xAl (x= 5.0 and 8.3 at.%)---on their twin-energy pathways called the generalized planar fault energies (GPFE). We also link the twinning behavior of Cu-Al alloys to their electronic structure by determining the effect of solute Al on the valence charge density redistribution at the SF through ab initio DFT. Further, while several efforts have been undertaken to incorporate twinning for predicting stress-strain response of fcc materials, a fundamental law for critical twinning stress has not yet emerged. We resolve this long-standing issue by linking quantitatively the twin-energy pathways (GPFE) obtained via ab initio DFT to heterogeneous, dislocation-based twin nucleation models. We establish an analytical expression that quantitatively predicts the critical twinning stress in fcc metals in agreement with experiments without requiring any empiricism at any length scale. Our theory connects twinning stress to twin-energy pathways and predicts a monotonic relation between stress and unstable twin stacking fault energy revealing the physics of twinning. We further demonstrate that the theory holds for fcc alloys as well. Our theory inherently accounts for directional nature of twinning which available

  14. Comprehensive first-principles study of stable stacking faults in hcp metals

    International Nuclear Information System (INIS)

    Yin, Binglun; Wu, Zhaoxuan; Curtin, W.A.

    2017-01-01

    The plastic deformation in hcp metals is complex, with the associated dislocation core structures and properties not well understood on many slip planes in most hcp metals. A first step in establishing the dislocation properties is to examine the stable stacking fault energy and its structure on relevant slip planes. However, this has been perplexing in the hcp structure due to additional in-plane displacements on both sides of the slip plane. Here, density functional theory guided by crystal symmetry analysis is used to study all relevant stable stacking faults in 6 hcp metals (Mg, Ti, Zr, Re, Zn, Cd). Specially, the stable stacking fault energy, position, and structure on the Basal, Prism I and II, Pyramidal I and II planes are determined using all-periodic supercells with full atomic relaxation. All metals show similar stacking fault position and structure as dictated by crystal symmetry, but the associated stacking fault energy, being governed by the atomic bonding, differs significantly among them. Stacking faults on all the slip planes except the Basal plane show substantial out-of-plane displacements while stacking faults on the Prism II, Pyramidal I and II planes show additional in-plane displacements, all extending to multiple atom layers. The in-plane displacements are not captured in the standard computational approach for stacking faults, and significant differences are shown in the energies of such stacking faults between the standard approach and fully-relaxed case. The existence of well-defined stable stacking fault on the Pyramidal planes suggests zonal dislocations are unlikely. Calculations on the equilibrium partial separation further suggests 〈c + a〉 dissociation into three partials on the Pyramidal I plane is unlikely and 〈c〉 dissociation on Prism planes is unlikely to be stable against climb-dissociation onto the Basal planes in these metals.

  15. Significance of grain boundaries and stacking faults on hydrogen storage properties of Mg2Ni intermetallics processed by high-pressure torsion

    International Nuclear Information System (INIS)

    Hongo, Toshifumi; Edalati, Kaveh; Arita, Makoto; Matsuda, Junko; Akiba, Etsuo; Horita, Zenji

    2015-01-01

    Mg 2 Ni intermetallics are processed using three different routes to produce three different microstructural features: annealing at high temperature for coarse grain formation, severe plastic deformation through high-pressure torsion (HPT) for nanograin formation, and HPT processing followed by annealing for the introduction of stacking faults. It is found that both grain boundaries and stacking faults are significantly effective to activate the Mg 2 Ni intermetallics for hydrogen storage at 423 K (150 °C). The hydrogenation kinetics is also considerably enhanced by the introduction of large fractions of grain boundaries and stacking faults while the hydrogenation thermodynamics remains unchanged. This study shows that, similar to grain boundaries and cracks, stacking faults can act as quick pathways for the transportation of hydrogen in the hydrogen storage materials

  16. Detection of stacking faults breaking the [110]/[110] symmetry in ferromagnetic semiconductors (Ga,Mn)As and (Ga,Mn)(As,P)

    International Nuclear Information System (INIS)

    Kopecky, M.; Kub, J.; Maca, F.; Masek, J.; Pacherova, O.; Rushforth, A. W.; Gallagher, B. L.; Campion, R. P.; Novak, V.; Jungwirth, T.

    2011-01-01

    We report on high-resolution x-ray diffraction measurements of (Ga,Mn)As and (Ga,Mn)(As,P) epilayers. We observe a structural anisotropy in the form of stacking faults that are present in the (111) and (111) planes and absent in the (111) and (111) planes. They occupy 10 -2 %-10 -1 % of the ferromagnetic epilayer volume while no stacking faults are detected in the controlled, undoped GaAs epilayer. Full-potential density functional calculations provide additional evidence that the formation of the stacking faults is promoted by Mn attracted to these structural defects. The enhanced Mn density along the common [110] direction of the stacking fault planes produces a symmetry-breaking mechanism of a strength and sense that can account for the uniaxial [110]/[110] magnetocrystalline anisotropy of these ferromagnetic semiconductors.

  17. Stacking fault density and bond orientational order of fcc ruthenium nanoparticles

    Science.gov (United States)

    Seo, Okkyun; Sakata, Osami; Kim, Jae Myung; Hiroi, Satoshi; Song, Chulho; Kumara, Loku Singgappulige Rosantha; Ohara, Koji; Dekura, Shun; Kusada, Kohei; Kobayashi, Hirokazu; Kitagawa, Hiroshi

    2017-12-01

    We investigated crystal structure deviations of catalytic nanoparticles (NPs) using synchrotron powder X-ray diffraction. The samples were fcc ruthenium (Ru) NPs with diameters of 2.4, 3.5, 3.9, and 5.4 nm. We analyzed average crystal structures by applying the line profile method to a stacking fault model and local crystal structures using bond orientational order (BOO) parameters. The reflection peaks shifted depending on rules that apply to each stacking fault. We evaluated the quantitative stacking faults densities for fcc Ru NPs, and the stacking fault per number of layers was 2-4, which is quite large. Our analysis shows that the fcc Ru 2.4 nm-diameter NPs have a considerably high stacking fault density. The B factor tends to increase with the increasing stacking fault density. A structural parameter that we define from the BOO parameters exhibits a significant difference from the ideal value of the fcc structure. This indicates that the fcc Ru NPs are highly disordered.

  18. Stacking faults in the Co7W6 isomorph of the µ phase

    NARCIS (Netherlands)

    Carvalho, P.A.; Hosson, J.Th.M. De

    2001-01-01

    This paper concentrates on an electron microscopy study of stacking faults on pyramidal planes, that are concurrent with the characteristic twins, in the Co7W6 isomorph of the µ phase. The faults are frequently found to inflect over 9° when crossing a twin domain.

  19. A stacking-fault based microscopic model for platelets in diamond

    Science.gov (United States)

    Antonelli, Alex; Nunes, Ricardo

    2005-03-01

    We propose a new microscopic model for the 001 planar defects in diamond commonly called platelets. This model is based on the formation of a metastable stacking fault, which can occur because of the ability of carbon to stabilize in different bonding configurations. In our model the core of the planar defect is basically a double layer of three-fold coordinated sp^2 carbon atoms embedded in the common sp^3 diamond structure. The properties of the model were determined using ab initio total energy calculations. All significant experimental signatures attributed to the platelets, namely, the lattice displacement along the [001] direction, the asymmetry between the [110] and the [11 0] directions, the infrared absorption peak B^' , and broad luminescence lines that indicate the introduction of levels in the band gap, are naturally accounted for in our model. The model is also very appealing from the point of view of kinetics, since naturally occurring shearing processes will lead to the formation of the metastable fault.Authors acknowledge financial support from the Brazilian agencies FAPESP, CNPq, FAEP-UNICAMP, FAPEMIG, and Instituto do Milênio em Nanociências-MCT

  20. Application of damping mechanism model and stacking fault probability in Fe-Mn alloy

    International Nuclear Information System (INIS)

    Huang, S.K.; Wen, Y.H.; Li, N.; Teng, J.; Ding, S.; Xu, Y.G.

    2008-01-01

    In this paper, the damping mechanism model of Fe-Mn alloy was analyzed using dislocation theory. Moreover, as an important parameter in Fe-Mn based alloy, the effect of stacking fault probability on the damping capacity of Fe-19.35Mn alloy after deep-cooling or tensile deformation was also studied. The damping capacity was measured using reversal torsion pendulum. The stacking fault probability of γ-austenite and ε-martensite was determined by means of X-ray diffraction (XRD) profile analysis. The microstructure was observed using scanning electronic microscope (SEM). The results indicated that with the strain amplitude increasing above a critical value, the damping capacity of Fe-19.35Mn alloy increased rapidly which could be explained using the breakaway model of Shockley partial dislocations. Deep-cooling and suitable tensile deformation could improve the damping capacity owning to the increasing of stacking fault probability of Fe-19.35Mn alloy

  1. Influence of Stacking Fault Energy (SFE) on the deformation mode of stainless steels

    International Nuclear Information System (INIS)

    Li, X.; Van Renterghem, W.; Al Mazouzi, A.

    2008-01-01

    The sensibility to irradiation-assisted stress corrosion cracking (IASCC) of stainless steels in light water reactor (LWR) can be caused by the localisation of deformation that takes place in these materials. Dislocation channelling and twinning modes of deformation can induce localised plasticity leading to failure. Stacking fault energy (SFE) plays an important role in every process of plastic deformation behaviour, especially in twinning and dislocation channelling. In order to correlate localised deformation with stacking fault energy, this parameter has been experimentally determined by transmission electron microscope (TEM) using both dislocation node and multiple ribbons methods after compression in three different model alloys. Detailed deformation behaviour of three fabricated alloys with different stacking fault energy before and after tensile tests at temperatures from -150 deg C to 300 deg C, will be shown and discussed based on mechanical test and TEM observation. (authors)

  2. The collapse of stacking-fault tetrahedra by interaction with gliding dislocations

    International Nuclear Information System (INIS)

    Matsukawa, Y.; Osetsky, Yu.N.; Stoller, R.E.; Zinkle, S.J.

    2005-01-01

    The collapse of stacking-fault tetrahedra (SFT) by gliding dislocations was observed in in situ straining experiments in a transmission electron microscope (TEM). A stacking-fault tetrahedron was collapsed by intersection with a gliding perfect dislocation: only the base portion divided by the gliding plane of the dislocation annihilated, while the apex portion remained intact. As a result of analysis on evolution of atom configuration induced by intersection with perfect dislocation in SFT, it was found that an unusual atom configuration inevitably appeared in one of the ledges formed on stacking-fault planes, which is traditionally called I-ledge: the atoms on adjacent (1 1 1) planes were overlapping each other. The overlapping configuration provides a strong repulsive force, being a conceivable driving force to induce a chain reaction of atom displacements that collapses the SFT base portion

  3. Broadband infrared photoluminescence in silicon nanowires with high density stacking faults.

    Science.gov (United States)

    Li, Yang; Liu, Zhihong; Lu, Xiaoxiang; Su, Zhihua; Wang, Yanan; Liu, Rui; Wang, Dunwei; Jian, Jie; Lee, Joon Hwan; Wang, Haiyan; Yu, Qingkai; Bao, Jiming

    2015-02-07

    Making silicon an efficient light-emitting material is an important goal of silicon photonics. Here we report the observation of broadband sub-bandgap photoluminescence in silicon nanowires with a high density of stacking faults. The photoluminescence becomes stronger and exhibits a blue shift under higher laser powers. The super-linear dependence on excitation intensity indicates a strong competition between radiative and defect-related non-radiative channels, and the spectral blue shift is ascribed to the band filling effect in the heterostructures of wurtzite silicon and cubic silicon created by stacking faults.

  4. Calculation of the energy of stacking faults in uranium dioxide

    International Nuclear Information System (INIS)

    Lefebvre, J.-M.; Soullard, J.

    1976-01-01

    Energy computations of some (100), (110) and (111), planar defects were performed using an ionic bond model for stoichiometric uranium dioxyde. The repulsive contribution to the fault was estimated in two different ways, i.e. using the Born-Mayer classical treatment, or potentials derived from shell model calculations. The stability of the various defect configurations has been studied; on the basis of the numerical values, it may be concluded that dislocation dissociation is unlikely in stoichiometric uranium dioxyde. (Auth.)

  5. Effects of Cl+ and F+ implantation of oxidation-induced stacking faults in silicon

    NARCIS (Netherlands)

    Xu, J.Y.; Bronsveld, P.M.; Boom, G.; Hosson, J.Th.M. De

    1984-01-01

    Three implantation effects were investigated in floating-zone-grown silicon: (a) the effect of Cl+ implantation resulting in the shrinkage of oxidation-induced stacking faults; (b) the effect of F+ implantation giving rise to defaulting of the 1/3 [111] Frank dislocations into 1/2[110] perfect

  6. Stacking fault energy measurements in WSe2 single crystals using weak-beam techniques

    International Nuclear Information System (INIS)

    Agarwal, M.K.; Patel, J.V.; Patel, N.G.

    1981-01-01

    The weak-beam method of electron microscopy is used to observe threefold dislocations in WSe 2 single crystals grown by direct vapour transport method. The widths of the three fold ribbons are used to determine the stacking fault energy in these crystals. Variation of the width of the ribbons with temperature are also studied and discussed. (author)

  7. Crystal structure of stacking faults in InGaAs/InAlAs/InAs heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Trunkin, I. N.; Presniakov, M. Yu.; Vasiliev, A. L., E-mail: a.vasiliev56@gmail.com [National Research Centre “Kurchatov Institute” (Russian Federation)

    2017-03-15

    Stacking faults and dislocations in InGaAs/InAlAs/InAs heterostructures have been studied by electron microscopy. The use of different techniques of transmission electron microscopy (primarily, highresolution dark-field scanning transmission electron microscopy) has made it possible to determine the defect structure at the atomic level.

  8. Ab initio study of antiphase boundaries and stacking faults in L12 and DO22 compounds

    DEFF Research Database (Denmark)

    Rosengaard, N. M.; Skriver, Hans Lomholt

    1994-01-01

    We have performed ab initio calculations of the energies of antiphase boundaries as well as complex and superlattice intrinsic stacking faults in nine intermetallic compounds observed in the face-centered-cubic L1(2) and DO22 structures. The calculations were performed by means of a Green...

  9. Temperature-dependent stability of stacking faults in Al, Cu and Ni: first-principles analysis.

    Science.gov (United States)

    Bhogra, Meha; Ramamurty, U; Waghmare, Umesh V

    2014-09-24

    We present comparative analysis of microscopic mechanisms relevant to plastic deformation of the face-centered cubic (FCC) metals Al, Cu, and Ni, through determination of the temperature-dependent free energies of intrinsic and unstable stacking faults along [1 1̄ 0] and [1 2̄ 1] on the (1 1 1) plane using first-principles density-functional-theory-based calculations. We show that vibrational contribution results in significant decrease in the free energy of barriers and intrinsic stacking faults (ISFs) of Al, Cu, and Ni with temperature, confirming an important role of thermal fluctuations in the stability of stacking faults (SFs) and deformation at elevated temperatures. In contrast to Al and Ni, the vibrational spectrum of the unstable stacking fault (USF[1 2̄ 1]) in Cu reveals structural instabilities, indicating that the energy barrier (γusf) along the (1 1 1)[1 2̄ 1] slip system in Cu, determined by typical first-principles calculations, is an overestimate, and its commonly used interpretation as the energy release rate needed for dislocation nucleation, as proposed by Rice (1992 J. Mech. Phys. Solids 40 239), should be taken with caution.

  10. Effect of stacking fault energy on steady-state creep rate of face ...

    African Journals Online (AJOL)

    Continuum elastic theory was used to establish the relationships between the force of interaction required to constrict dislocation partials, energy of constriction and climb velocity of the constricted thermal jogs, in order to examine the effect of stacking fault energy (SFE) on steady state creep rate of face centered cubic ...

  11. Stacking faults on (001) in transition-metal disilicides with the C11b structure

    International Nuclear Information System (INIS)

    Ito, K.; Nakamoto, T.; Inui, H.; Yamaguchi, M.

    1997-01-01

    Stacking faults on (001) in MoSi 2 and WSi 2 with the C11 b structure have been characterized by transmission electron microscopy (TEM), using their single crystals grown by the floating-zone method. Although WSi 2 contains a high density of stacking faults, only several faults are observed in MoSi 2 . For both crystals, (001) faults are characterized to be of the Frank-type in which two successive (001) Si layers are removed from the lattice, giving rise to a displacement vector parallel to [001]. When the displacement vector of faults is expressed in the form of R = 1/n[001], however, their n values are slightly deviated from the exact value of 3, because of dilatation of the lattice in the direction perpendicular to the fault, which is caused by the repulsive interaction between Mo (W) layers above and below the fault. Matching of experimental high-resolution TEM images with calculated ones indicates n values to be 3.12 ± 0.10 and 3.34 ± 0.10 for MoSi 2 and WSi 2 , respectively

  12. Strong carrier localization in stacking faults in semipolar (11-22) GaN

    Science.gov (United States)

    Okur, Serdal; Monavarian, Morteza; Das, Saikat; Izyumskaya, Natalia; Zhang, Fan; Avrutin, Vitaliy; Morkoç, Hadis; Özgür, Ümit

    2015-03-01

    The effects of stacking faults (SFs) on optical processes in epitaxially grown semipolar (1122) GaN on m-sapphire substrate have been investigated in detail using steady-state photoluminescence (PL) and time- and polarization-resolved PL. We demonstrate that the carrier recombination dynamics are substantially influenced due to strong carrier localization in the stacking faults. In addition to nonradiative recombination, carrier trapping/detrapping and carrier transfer between the stacking faults and donors are also found to be among the mechanisms affecting the recombination dynamics at different temperatures. PL decay times of both I1-type BSF and 3.31 eV SF (E-type BSF or prismatic stacking fault) do not show temperature dependence up to 80 K while 3.31 eV SF exhibits longer PL decay times (~3 ns) at low temperatures as compared to I1-type BSF (~1 ns), indicative of lower efficiency for radiative recombination. After 80 K, PL decay times decreased by power of ~-1 and ~-2 for 3.31 eV SF and I1-type BSF, respectively. It is obtained from radiative decay times with respect to temperature that the carrier localization becomes higher in I1-type BSF compared to 3.31 eV SF increasing the temperature. I1-type BSF also shows higher PL intensity, which is attributed to larger density, and therefore, larger contribution to recombination dynamics as compared to other type of stacking faults. Polarization-resolved PL measurements also revealed that the degree of polarization for the I1-type BSF (0.30) was twice that for the 3.31 eV SF.

  13. X-ray diffuse scattering study of the kinetics of stacking fault growth and annihilation in boron-implanted silicon

    Science.gov (United States)

    Luebbert, D.; Arthur, J.; Sztucki, M.; Metzger, T. H.; Griffin, P. B.; Patel, J. R.

    2002-10-01

    Stacking faults in boron-implanted silicon give rise to streaks or rods of scattered x-ray intensity normal to the stacking fault plane. We have used the diffuse scattering rods to follow the growth of faults as a function of time when boron-implanted silicon is annealed in the range of 925 to 1025 degC. From the growth kinetics we obtain an activation energy for interstitial migration in silicon: EI=1.98plus-or-minus0.06 eV. Fault intensity and size versus time results indicate that faults do not shrink and disappear, but rather are annihilated by a dislocation reaction mechanism.

  14. Stacking faults and mechanisms strain-induced transformations of hcp metals (Ti, Mg) during mechanical activation in liquid hydrocarbons

    Science.gov (United States)

    Lubnin, A. N.; Dorofeev, G. A.; Nikonova, R. M.; Mukhgalin, V. V.; Lad'yanov, V. I.

    2017-11-01

    The evolution of the structure and substructure of metals Ti and Mg with hexagonal close-packed (hcp) lattice is studied during their mechanical activation in a planetary ball mill in liquid hydrocarbons (toluene, n-heptane) and with additions of carbon materials (graphite, fullerite, nanotubes) by X-ray diffraction, scanning electron microscopy, and chemical analysis. The temperature behavior and hydrogen-accumulating properties of mechanocomposites are studied. During mechanical activation of Ti and Mg, liquid hydrocarbons decay, metastable nanocrystalline titanium carbohydride Ti(C,H) x and magnesium hydride β-MgH2 are formed, respectively. The Ti(C,H) x and MgH2 formation mechanisms during mechanical activation are deformation ones and are associated with stacking faults accumulation, and the formation of face-centered cubic (fcc) packing of atoms. Metastable Ti(C,H)x decays at a temperature of 550°C, the partial reverse transformation fcc → hcp occurs. The crystalline defect accumulation (nanograin boundaries, stacking faults), hydrocarbon destruction, and mechanocomposite formation leads to the enhancement of subsequent magnesium hydrogenation in the Sieverts reactor.

  15. CRYSTALLIZATION EXPERIMENTS ON AMORPHOUS MAGNESIUM SILICATE. II. EFFECT OF STACKING FAULTS ON INFRARED SPECTRA OF ENSTATITE

    International Nuclear Information System (INIS)

    Murata, K.; Chihara, H.; Koike, C.; Takakura, T.; Imai, Y.; Tsuchiyama, A.; Noguchi, T.

    2009-01-01

    We carried out experiments of low-temperature infrared spectroscopy and transmission electron microscopy of enstatite (MgSiO 3 ) synthesized by heating of amorphous magnesium silicate. There is a discrepancy between the infrared feature of enstatite obtained in this experiment and that of fine powdered single crystals. This reflects stacking disorder of enstatite. We show that circumstellar dust emission of enstatite is similar to the infrared feature measured in this experiment. This result strongly suggests that circumstellar enstatite has abundant stacking faults and is different from the single crystal.

  16. The relation between ductility and stacking fault energies in Mg and Mg–Y alloys

    International Nuclear Information System (INIS)

    Sandlöbes, S.; Friák, M.; Zaefferer, S.; Dick, A.; Yi, S.; Letzig, D.; Pei, Z.; Zhu, L.-F.; Neugebauer, J.; Raabe, D.

    2012-01-01

    The underlying mechanisms that are responsible for the improved room-temperature ductility in Mg–Y alloys compared to pure Mg are investigated by transmission electron microscopy and density functional theory. Both methods show a significant decrease in the intrinsic stacking fault I 1 energy (I 1 SFE) with the addition of Y. The influence of the SFE on the relative activation of different competing deformation mechanisms (basal, prismatic, pyramidal slip) is discussed. From this analysis we suggest a key mechanism which explains the transition from primary basal slip in hexagonal close-packed Mg to basal plus pyramidal slip in solid solution Mg–Y alloys. This mechanism is characterized by enhanced nucleation of 〈c + a〉 dislocations where the intrinsic stacking fault I 1 (ISF 1 ) acts as heterogeneous source for 〈c + a〉 dislocations. Possible electronic and geometric reasons for the modification of the SFE by substitutional Y atoms are identified and discussed.

  17. AIC-based diffraction stacking for local earthquake locations at the Sumatran Fault (Indonesia)

    Science.gov (United States)

    Hendriyana, Andri; Bauer, Klaus; Muksin, Umar; Weber, Michael

    2018-05-01

    We present a new workflow for the localization of seismic events which is based on a diffraction stacking approach. In order to address the effects from complex source radiation patterns, we suggest to compute diffraction stacking from a characteristic function (CF) instead of stacking the original waveform data. A new CF, which is called in the following mAIC (modified from Akaike Information Criterion) is proposed. We demonstrate that both P- and S-wave onsets can be detected accurately. To avoid cross-talk between P and S waves due to inaccurate velocity models, we separate the P and S waves from the mAIC function by making use of polarization attributes. Then, the final image function is represented by the largest eigenvalue as a result of the covariance analysis between P- and S-image functions. Results from synthetic experiments show that the proposed diffraction stacking provides reliable results. The workflow of the diffraction stacking method was finally applied to local earthquake data from Sumatra, Indonesia. Recordings from a temporary network of 42 stations deployed for nine months around the Tarutung pull-apart basin were analysed. The seismic event locations resulting from the diffraction stacking method align along a segment of the Sumatran Fault. A more complex distribution of seismicity is imaged within and around the Tarutung basin. Two lineaments striking N-S were found in the centre of the Tarutung basin which support independent results from structural geology.

  18. Application of Post-stack migration to seismic data associated with fault structures

    OpenAIRE

    Koduru Anitha; Mohanty P. R

    2015-01-01

    In hydrocarbon exploration, wave-equation migration techniques play an important role in imaging the complex geological structures. Usually, post-stack migration scheme is applied to the seismic data to improve the resolution with restoration of dipping reflectors to their true position. As a result, the migrated time sections are interpretable in terms of subsurface features. As a numerical study, three fault models are considered for the present study. First of all, ...

  19. Heteroepitaxial growth of basal plane stacking fault free a-plane GaN

    Energy Technology Data Exchange (ETDEWEB)

    Wieneke, Matthias; Hempel, Thomas; Noltemeyer, Martin; Witte, Hartmut; Dadgar, Armin; Blaesing, Juergen; Christen, Juergen; Krost, Alois [Otto-von-Guericke Universitaet Magdeburg, FNW/IEP, Magdeburg (Germany)

    2010-07-01

    Growth of light emitting quantum-wells based on a-plane GaN is a possibility to reduce or even to avoid polarization correlated luminescence red shift and reduction of radiative recombination efficiency. But until now heteroepitaxially grown a-plane GaN films are characterized by a poor crystalline quality expressed by a high density of basal plane stacking faults (BSF) and partial dislocations. We present Si doped a-plane GaN films grown on r-plane sapphire substrates by metal organic vapor phase epitaxy using high temperature AlGaN nucleation layers. FE-SEM images revealed three dimensionally grown GaN crystallites sized up to tenth micrometer in the basal plane and a few tenth micrometers along the c-axes. Though, the full width at half maxima of the X-ray diffraction {omega}-scans of the in-plane GaN(1 anti 100) and GaN(0002) Bragg reflections exhibited a very high crystal quality. Furthermore, luminescence spectra were dominated by near band gap emission, while there was no separated peak of the basal plane stacking fault. In summary we present heteroepitaxially grown a-plane GaN without an evidence of basal plane stacking faults in X-ray diffraction measurements and luminescence spectra.

  20. Deformation-induced martensitic transformation in a 201 austenitic steel: The synergy of stacking fault energy and chemical driving force

    Energy Technology Data Exchange (ETDEWEB)

    Moallemi, M., E-mail: m.moallemi@ma.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Kermanpur, A. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Najafizadeh, A. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Fould Institute of Technology, Fouladshahr, Isfahan, 8491663763 (Iran, Islamic Republic of); Rezaee, A.; Baghbadorani, H. Samaei; Nezhadfar, P. Dastranjy [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2016-01-20

    The present study deals with the correlation of stacking fault energy's synergy and driving force in the formation of deformation-induced martensitic transformation in a 201 austenitic stainless steel. The fraction of deformation-induced martensite was characterized by means of X-ray diffraction and magnetic induction techniques. The kinetics of the martensite formation versus applied strain was evaluated through the sigmoidal model. It was shown that the volume fraction of ά-martensite is closely related to the driving force/SFE ratio of the alloy. The results also showed that the martensite content is similar in both XRD and magnetic methods and the applied sigmoidal model was consistent with the obtained experimental data.

  1. Fault Creep along the Southern San Andreas from Interferometric Synthetic Aperture Radar, Permanent Scatterers, and Stacking

    Science.gov (United States)

    Lyons, Suzanne; Sandwell, David

    2003-01-01

    Interferometric synthetic aperture radar (InSAR) provides a practical means of mapping creep along major strike-slip faults. The small amplitude of the creep signal (less than 10 mm/yr), combined with its short wavelength, makes it difficult to extract from long time span interferograms, especially in agricultural or heavily vegetated areas. We utilize two approaches to extract the fault creep signal from 37 ERS SAR images along the southem San Andreas Fault. First, amplitude stacking is utilized to identify permanent scatterers, which are then used to weight the interferogram prior to spatial filtering. This weighting improves correlation and also provides a mask for poorly correlated areas. Second, the unwrapped phase is stacked to reduce tropospheric and other short-wavelength noise. This combined processing enables us to recover the near-field (approximately 200 m) slip signal across the fault due to shallow creep. Displacement maps fiom 60 interferograms reveal a diffuse secular strain buildup, punctuated by localized interseismic creep of 4-6 mm/yr line of sight (LOS, 12-18 mm/yr horizontal). With the exception of Durmid Hill, this entire segment of the southern San Andreas experienced right-lateral triggered slip of up to 10 cm during the 3.5-year period spanning the 1992 Landers earthquake. The deformation change following the 1999 Hector Mine earthquake was much smaller (4 cm) and broader than for the Landers event. Profiles across the fault during the interseismic phase show peak-to-trough amplitude ranging from 15 to 25 mm/yr (horizontal component) and the minimum misfit models show a range of creeping/locking depth values that fit the data.

  2. Impact of Alloying on Stacking Fault Energies in γ-TiAl

    Directory of Open Access Journals (Sweden)

    Phillip Dumitraschkewitz

    2017-11-01

    Full Text Available Microstructure and mechanical properties are key parameters influencing the performance of structural multi-phase alloys such as those based on intermetallic TiAl compounds. There, the main constituent, a γ -TiAl phase, is derived from a face-centered cubic structure. Consequently, the dissociation of dislocations and generation of stacking faults (SFs are important factors contributing to the overall deformation behavior, as well as mechanical properties, such as tensile/creep strength and, most importantly, fracture elongation below the brittle-to-ductile transition temperature. In this work, SFs on the { 111 plane in γ -TiAl are revisited by means of ab initio calculations, finding their energies in agreement with previous reports. Subsequently, stacking fault energies are evaluated for eight ternary additions, namely group IVB–VIB elements, together with Ti off-stoichiometry. It is found that the energies of superlattice intrinsic SFs, anti-phase boundaries (APBs, as well as complex SFs decrease by 20–40% with respect to values in stoichiometric γ -TiAl once an alloying element X is present in the fault plane having thus a composition of Ti-50Al-12.5X. In addition, Mo, Ti and V stabilize the APB on the (111 plane, which is intrinsically unstable at 0 K in stoichiometric γ -TiAl.

  3. Effects of stacking fault energy on the creep behaviors of Ni-base superalloy

    International Nuclear Information System (INIS)

    Tian, Chenggang; Han, Guoming; Cui, Chuanyong; Sun, Xiaofeng

    2014-01-01

    Highlights: • The decrease of SFE could promote the dislocation dissociation. • The creep mechanisms were significantly affected by the SFE of the alloys. • The creep properties of the alloys improved with the decrease of SFE by facilitating the microtwinning process. - Abstract: Cobalt in a 23 wt.% Co containing Ni-base superalloys was systematically substituted by Ni in order to study the effects of stacking fault energy (SFE) on the creep mechanisms. The deformation microstructures of the alloys during different creep stages at 725 °C and 630 MPa were investigated by transmission electron microscopy (TEM). The results showed that the creep life increased as the SFE decreased corresponding to the increase of Co content in the alloys. At primary creep stage, the dislocation was difficult to dissociate independent of SFE. In contrast, at secondary and tertiary creep stages the dislocations dissociated at γ/γ′ interface and the partial dislocation started to shear γ′ precipitates, leaving isolated faults (IFs) in high SFE alloy, while the dislocations dissociated in the matrix and the partials swept out the matrix and γ′ precipitates creating extended stacking faults (ESFs) or deformation microtwins which were involved in diffusion-mediated reordering in low SFE alloy. It is suggested that the deformation microtwinning process should be favorable with the decrease of SFE, which could enhance the creep resistance and improve the creep properties of the alloys

  4. Structure and stacking faults in layered Mg-Zn-Y alloys: A first-principles study

    International Nuclear Information System (INIS)

    Datta, Aditi; Waghmare, U.V.; Ramamurty, U.

    2008-01-01

    We use first-principles density functional theory total energy calculations based on pseudo-potentials and plane-wave basis to assess stability of the periodic structures with different stacking sequences in Mg-Zn-Y alloys. For pure Mg, we find that the 6-layer (6l) structure with the ABACAB stacking is most stable after the lowest energy hcp (2l) structure with ABAB stacking. Addition of 2 at.% Y leads to stabilization of the structure to 6l sequence whereas the addition of 2 at.% Zn makes the 6l energetically comparable to that of the hcp. Stacking fault (SF) on the basal plane of 6l structure is higher in energy than that of the hcp 2l Mg, which further increases upon Y doping and decreases significantly with Zn doping. SF energy surface for the prismatic slip indicates activation of non-basal slip in alloys with a 6l structure. Charge density analysis shows that the 2l and 6l structures are electronically similar which might be a cause for better stability of 6l structure over a 4l sequence or other periodic structures. Thus, in an Mg-Zn-Y alloy, Y stabilizes the long periodicity, while its mechanical properties are further improved due to Zn doping

  5. Effect of stacking faults on the magnetocrystalline anisotropy of hcp Co-based nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Kha, Tuan Mai; Schoenstein, Frédéric; Zighem, Fatih [Laboratoire des Sciences des Procédés et des Matériaux (LSPM-UPR3407), CNRS-Université Paris XIII, Sorbonne Paris Cité, Villetaneuse (France); Nowak, Sophie [Université Paris Diderot, Sorbonne Paris Cité, ITODYS, CNRS UMR 7086, 15 rue J.-A. de Baïf, 75205 Paris Cedex 13 (France); Leridon, Brigitte [LPEM, ESPCI Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC, F-75005 Paris (France); Jouini, Noureddine [Laboratoire des Sciences des Procédés et des Matériaux (LSPM-UPR3407), CNRS-Université Paris XIII, Sorbonne Paris Cité, Villetaneuse (France); Mercone, Silvana, E-mail: silvana.mercone@univ-paris13.fr [Laboratoire des Sciences des Procédés et des Matériaux (LSPM-UPR3407), CNRS-Université Paris XIII, Sorbonne Paris Cité, Villetaneuse (France)

    2017-01-15

    Replacing materials based on rare-earth elements in current permanent magnets is a real scientific, economic and environmental challenge. Ferromagnetic 3d transition metals seem an apt direction to go in this field, due to their high residual magnetization and thermal stability. In order to improve their coercive behavior, nanostructured magnets based on the assembly of high-aspect-ratio nanoparticles (i.e. cobalt based nanorods and nanowires) have recently been proposed. In these, the nanoparticle morphology itself drives the magnetization reversal mechanism. This purely geometrical effect seems to obscure the effects of structural defects, although it is clear that high magnetocrystalline energy is required to maintain a stable orientation of the magnetic moment inside the nanoparticles. We present here an experimental study whose aim is to distinguish the role of the stacking faults from the effects of shape and morphology on the magnetization reversal mechanism in cobalt-based nanowires. Coercive field results have been obtained on Co{sub 80}Ni{sub 20} nanowires synthesized by a polyol process. Through accurate control of shape and morphology, it was possible to discard the effects of shape and thus to highlight the influence of crystal defects on the magnetism of Co{sub 80}Ni{sub 20} nanowires. A micromagnetic study, consistent with the experimental analyses, is also presented. The results discussed in this work clearly show that even if the morphological characteristics are conducive to a high coercive field, the presence of numerous stacking faults has the opposite effect and leads to materials with a significantly lower coercive field than expected, which is not suitable for permanent magnet applications. - Highlights: • Optimization of the nanowires magnetic properties for permanent magnet applications. • Magnetization reversal mechanism study as function of the shape, structural and chemical homogeneity. • Effect of stacking faults on the coercive

  6. A complete absorption mechanism of stacking fault tetrahedron by screw dislocation in copper

    International Nuclear Information System (INIS)

    Fan, Haidong; Wang, Qingyuan

    2013-01-01

    It was frequently observed in experiments that stacking fault tetrahedron (SFT) can be completely absorbed by dislocation and generate defect-free channels in irradiated materials, but the mechanism is still open. In this paper, molecular dynamics (MD) was used to explore the dislocation mechanism of reaction between SFT and screw dislocation in copper. Our computational results reveal that, at high temperature, the SFT is completely absorbed by screw dislocation with the help of Lomer–Cottrell (LC) lock transforming into Lomer dislocation. This complete absorption mechanism is very helpful to understand the defect-free channels in irradiated materials

  7. Effect of stacking fault energy on high-temperature creep parameters of nickel-cobalt alloys

    International Nuclear Information System (INIS)

    Nerodenko, L.M.; Dabizha, E.V.

    1982-01-01

    Results of creep investigation are discussed for two alloys of the Ni-Co system. In terms of the structural creep model an analysis is made for the effect of stacking fault energy on averaged parameters of the dislocation structure: inovable dislocation density subgrain size, activation volume. The rate of steady-state creep is determined by the process of dislocation passing through the subgrain boundaries with activation energy of 171.0 and 211.5 kJ/mol for the Ni-25% Co and Ni-65% Co alloys, respectively

  8. Birnessite-type MnO2 nanosheets with layered structures under high pressure: elimination of crystalline stacking faults and oriented laminar assembly.

    Science.gov (United States)

    Sun, Yugang; Wang, Lin; Liu, Yuzi; Ren, Yang

    2015-01-21

    Squeezing out crystalline stacking faults: Birnessite-type δ-phase MnO2 microflowers containing interconnected ultrathin nanosheets are synthesized through a microwave-assisted hydrothermal process and exhibit a layered crystalline structure with significant stacking faults. Compressing these MnO2 nanosheets in a diamond anvil cell with high pressure up to tens of GPa effectively eliminates the crystalline stacking faults. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Stacking fault energy measurements in solid solution strengthened Ni-Cr-Fe alloys using synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Unfried-Silgado, Jimy [Metals Characterization and Processing Laboratory, Brazilian Nanothecnology National Laboratory - CNPEM/ABTLuS, Caixa Postal 6192, CEP 13083-970, Campinas, Sao Paulo (Brazil); Universidade Estadual de Campinas UNICAMP, Faculdade de Engenharia Mecanica FEM, Campinas (Brazil); Universidad Autonoma del Caribe, Grupo IMTEF, Ingenieria Mecanica, Barranquilla (Colombia); Wu, Leonardo [Metals Characterization and Processing Laboratory, Brazilian Nanothecnology National Laboratory - CNPEM/ABTLuS, Caixa Postal 6192, CEP 13083-970, Campinas, Sao Paulo (Brazil); Furlan Ferreira, Fabio [Universidade Federal do ABC, Centro de Ciencias Naturais e Humanas (CCNH), Sao Paulo (Brazil); Mario Garzon, Carlos [Universidad Nacional de Colombia, Departamento de Fisica, Bogota (Colombia); Ramirez, Antonio J, E-mail: antonio.ramirez@lnnano.org.br [Metals Characterization and Processing Laboratory, Brazilian Nanothecnology National Laboratory - CNPEM/ABTLuS, Caixa Postal 6192, CEP 13083-970, Campinas, Sao Paulo (Brazil)

    2012-12-15

    The stacking fault energy (SFE) in a set of experimental Ni-Cr-Fe alloys was determined using line profile analysis on synchrotron X-ray diffraction measurements. The methodology used here is supported by the Warren-Averbach calculations and the relationships among the stacking fault probability ({alpha}) and the mean-square microstrain (<{epsilon}{sup 2}{sub L}>). These parameters were obtained experimentally from cold-worked and annealed specimens extracted from the set of studied Ni-alloys. The obtained results show that the SFE in these alloys is strongly influenced by the kind and quantity of addition elements. Different effects due to the action of carbide-forming elements and the solid solution hardening elements on the SFE are discussed here. The simultaneous addition of Nb, Hf, and, Mo, in the studied Ni-Cr-Fe alloys have generated the stronger decreasing of the SFE. The relationships between SFE and the contributions on electronic structure from each element of additions were established.

  10. Stacking fault energy of C-alloyed steels: The effect of magnetism

    International Nuclear Information System (INIS)

    Lu, Song; Li, Ruihuan; Kádas, Krisztina; Zhang, Hualei; Tian, Yanzhong; Kwon, Se Kyun; Kokko, Kalevi; Hu, Qing-Miao; Hertzman, Staffan

    2017-01-01

    First-principles calculations have been performed to study the effect of C on the stacking fault energy (SFE) of paramagnetic γ-Fe and Fe−Cr−Ni austenitic steel. In these systems, the local magnetic structure is very sensitive to the volume in both fcc and hcp structures, which emphasizes the importance of the magnetovolume coupling effect on the SFE. The presence of C atom suppresses the local magnetic moments of Fe atoms in the first coordination shell of C. Compared to the hypothetical nonmagnetic case, paramagnetism significantly reduces the effect of C on the SFE. In the scenario of C being depleted from the stacking fault structure or twin boundaries, e.g., due to elevated temperature, where the chemical effect of C is dissipated, we calculate the C-induced volume expansion effect on the SFE. The volume induced change in the SFE corresponds to more than ∼ 50% of the total C effect on the SFE obtained assuming uniform C distribution.

  11. Use of porous silicon to minimize oxidation induced stacking fault defects in silicon

    International Nuclear Information System (INIS)

    Shieh, S.Y.; Evans, J.W.

    1992-01-01

    This paper presents methods for minimizing stacking fault defects, generated during oxidation of silicon, include damaging the back of the wafer or depositing poly-silicon on the back. In either case a highly defective structure is created and this is capable of gettering either self-interstitials or impurities which promote nucleation of stacking fault defects. A novel method of minimizing these defects is to form a patch of porous silicon on the back of the wafer by electrochemical etching. Annealing under inert gas prior to oxidation may then result in the necessary gettering. Experiments were carried out in which wafers were subjected to this treatment. Subsequent to oxidation, the wafers were etched to remove oxide and reveal defects. The regions of the wafer adjacent to the porous silicon patch were defect-free, whereas remote regions had defects. Deep level transient spectroscopy has been used to examine the gettering capability of porous silicon, and the paper discusses the mechanism by which the porous silicon getters

  12. Origin analysis of expanded stacking faults by applying forward current to 4H-SiC p-i-n diodes

    Science.gov (United States)

    Hayashi, Shohei; Naijo, Takanori; Yamashita, Tamotsu; Miyazato, Masaki; Ryo, Mina; Fujisawa, Hiroyuki; Miyajima, Masaaki; Senzaki, Junji; Kato, Tomohisa; Yonezawa, Yoshiyuki; Kojima, Kazutoshi; Okumura, Hajime

    2017-08-01

    Stacking faults expanded by the application of forward current to 4H-SiC p-i-n diodes were observed using a transmission electron microscope to investigate the expansion origin. It was experimentally confirmed that long-zonal-shaped stacking faults expanded from basal-plane dislocations converted into threading edge dislocations. In addition, stacking fault expansion clearly penetrated into the substrate to a greater depth than the dislocation conversion point. This downward expansion of stacking faults strongly depends on the degree of high-density minority carrier injection.

  13. Stacked Star Formation Rate Profiles of Bursty Galaxies Exhibit “Coherent” Star Formation

    Science.gov (United States)

    Orr, Matthew E.; Hayward, Christopher C.; Nelson, Erica J.; Hopkins, Philip F.; Faucher-Giguère, Claude-André; Kereš, Dušan; Chan, T. K.; Schmitz, Denise M.; Miller, Tim B.

    2017-11-01

    In a recent work based on 3200 stacked Hα maps of galaxies at z˜ 1, Nelson et al. find evidence for “coherent star formation”: the stacked star formation rate (SFR) profiles of galaxies above (below) the “star formation main sequence” (MS) are above (below) that of galaxies on the MS at all radii. One might interpret this result as inconsistent with highly bursty star formation and evidence that galaxies evolve smoothly along the MS rather than crossing it many times. We analyze six simulated galaxies at z˜ 1 from the Feedback in Realistic Environments (FIRE) project in a manner analogous to the observations to test whether the above interpretations are correct. The trends in stacked SFR profiles are qualitatively consistent with those observed. However, SFR profiles of individual galaxies are much more complex than the stacked profiles: the former can be flat or even peak at large radii because of the highly clustered nature of star formation in the simulations. Moreover, the SFR profiles of individual galaxies above (below) the MS are not systematically above (below) those of MS galaxies at all radii. We conclude that the time-averaged coherent star formation evident stacks of observed galaxies is consistent with highly bursty, clumpy star formation of individual galaxies and is not evidence that galaxies evolve smoothly along the MS.

  14. Application of Post-stack migration to seismic data associated with fault structures

    Science.gov (United States)

    Koduru, Anitha; Mohanty, P. R.

    2015-06-01

    In hydrocarbon exploration, wave-equation migration techniques play an important role in imaging the complex geological structures. Usually, post-stack migration scheme is applied to the seismic data to improve the resolution with restoration of dipping reflectors to their true position. As a result, the migrated time sections are interpretable in terms of subsurface features. As a numerical study, three fault models are considered for the present study. First of all, synthetic time sections are generated corresponding to three models. Later, post stack migration schemes such as Gazdag(PS), Phase-shift with turning rays and reverse time migration (T-K) domain techniques are applied in order to judge the imaging accuracy, preservation of true amplitude and computational speed. All the three post stack time migrated sections delineate the structure with their throw.However, the reverse time migrations (T-K) clearly delineate the reflectors in restoring the throw properly with minimum computational time. In order to test the validity the numerical results, similar exercise has been undertaken using field seismic data of KG basin, India. The results indicates that the field migrated sections are imaged. But, the reverse time migration (T-K ) provides the best subsurface image with restoration of reflectors and collapse of diffracted events with least computational time. Gazdag (PS) and Phase-Shift with turning migrated section shows the reduction of amplitude whereas, the reverse time migration preserved the amplitude fully.

  15. Basal-plane stacking faults in non-polar GaN studied by off-axis electron holography

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Lewis Z-Y; Rao, D V Sridhara; Kappers, M J; Humphreys, C J [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge, CB2 3QZ (United Kingdom); Geiger, D, E-mail: ZL249@cam.ac.u [Triebenberg Laboratory, Institute for Structure Physics, Technische Universitaet Dresden, D-01062 Dresden (Germany)

    2010-02-01

    We have studied basal-plane stacking faults in a non-polar (11-20) GaN epilayer using high-resolution electron microscopy and off-axis electron holography. The microstructure of the basal-plane stacking faults (BSFs) has been determined to be I{sub 1} type from high-resolution TEM images. High-resolution holograms along the [11-20] zone axis were obtained by off-axis electron holography on a Cs-corrected TEM, providing {approx}2 A spatial resolution in the reconstructed amplitude and phase images. Phase fluctuations across the stacking faults were detected, suggesting the presence of a built-in electric field. The uncertainties in the experiments and their interpretation are discussed.

  16. Determination of the stacking fault energies of face centured cubic metals and alloys by X-rays diffraction

    International Nuclear Information System (INIS)

    Borges, J.F.A.; Padilha, A.F.; Imakuma, K.

    1988-03-01

    An X-rays diffraction method was applied to measure the Stacking Fault Energies (SFE) of the AISI 304, AISI 316, AISI 347 and DIN-WERKSTOFF 1.4970 Austenitic Stainless Steels. The SFE determination plays an important role in the research of the mecanichal behaviour of the Metal and Alloys, their deformation mechanisms, stability of micro-structure and electronic configuration. The method is based on the relationship between the SFE and the ratio of the Mean Square Strains to the Stacking-Fault probability. The Mean Square Strain was evaluated by Fourier Analysis of X-rays Diffaction profiles, corrected to reduce instrumental effects, followed by the application of the Warren-Averbach method to the Fourier Coefficients. The Stacking-Fault probabilities were derived from the changes of peak separations between cold-worked and annealed specimens. (author) [pt

  17. X-ray diffraction study of stacking faults in a single crystal of 2H SiC

    International Nuclear Information System (INIS)

    Pandey, D.; Krishna, P.

    1977-01-01

    The nature of random stacking faults in a heavily disordered single crystal of 2H SiC has been investigated by studying the broadening of x-ray diffraction maxima. The intensity distribution along the 10.1 reciprocal lattice row was recorded on a four-circle, computer-controlled single crystal diffractometer. The 10.1 reflections with 1 even were found to be considerably broadened showing that the stacking faults present are predominantly intrinsic faults ( both growth and deformation faults). A careful study of the half-width values of different 10.1 reflections revealed that the fault probabilities are large. Exact expressions for the diffracted intensity and the observable diffraction effects were obtained and these were then used to calculate the deformation and growth fault probabilities which were found to be 0.20 and 0.11 respectively. It is suggested that several deformation fault configurations result from a clustering of growth faults. The results obtained are compared with those obtained for 2H ZnS crystals. (author)

  18. Polarization of stacking fault related luminescence in GaN nanorods

    Directory of Open Access Journals (Sweden)

    G. Pozina

    2017-01-01

    Full Text Available Linear polarization properties of light emission are presented for GaN nanorods (NRs grown along [0001] direction on Si(111 substrates by direct-current magnetron sputter epitaxy. The near band gap photoluminescence (PL measured at low temperature for a single NR demonstrated an excitonic line at ∼3.48 eV and the stacking faults (SFs related transition at ∼3.43 eV. The SF related emission is linear polarized in direction perpendicular to the NR growth axis in contrast to a non-polarized excitonic PL. The results are explained in the frame of the model describing basal plane SFs as polymorphic heterostructure of type II, where anisotropy of chemical bonds at the interfaces between zinc blende and wurtzite GaN subjected to in-built electric field is responsible for linear polarization parallel to the interface planes.

  19. Dislocation-stacking fault tetrahedron interaction: what can we learn from atomic-scale modelling

    International Nuclear Information System (INIS)

    Osetsky, Yu.N.; Stoller, R.E.; Matsukawa, Y.

    2004-01-01

    The high number density of stacking fault tetrahedra (SFTs) observed in irradiated fcc metals suggests that they should contribute to radiation-induced hardening and, therefore, taken into account when estimating mechanical properties changes of irradiated materials. The central issue is describing the individual interaction between a moving dislocation and an SFT, which is characterized by a very fine size scale, ∼100 nm. This scale is amenable to both in situ TEM experiments and large-scale atomic modelling. In this paper we present results of an atomistic simulation of dislocation-SFT interactions using molecular dynamics (MD). The results are compared with observations from in situ deformation experiments. It is demonstrated that in some cases the simulations and experimental observations are quite similar, suggesting a reasonable interpretation of experimental observations

  20. Identification of stacking faults in silicon carbide by polarization-resolved second harmonic generation microscopy.

    Science.gov (United States)

    Hristu, Radu; Stanciu, Stefan G; Tranca, Denis E; Polychroniadis, Efstathios K; Stanciu, George A

    2017-07-07

    Although silicon carbide is a highly promising crystalline material for a wide range of electronic devices, extended and point defects which perturb the lattice periodicity hold deep implications with respect to device reliability. There is thus a great need for developing new methods that can detect silicon carbide defects which are detrimental to device functionality. Our experiment demonstrates that polarization-resolved second harmonic generation microscopy can extend the efficiency of the "optical signature" concept as an all-optical rapid and non-destructive set of investigation methods for the differentiation between hexagonal and cubic stacking faults in silicon carbide. This technique can be used for fast and in situ characterization and optimization of growth conditions for epilayers of silicon carbide and similar materials.

  1. Effect of Re on stacking fault nucleation under shear strain in Ni by atomistic simulation

    International Nuclear Information System (INIS)

    Liu Zheng-Guang; Wang Chong-Yu; Yu Tao

    2014-01-01

    The effect of Re on stacking fault (SF) nucleation under shear strain in Ni is investigated using the climbing image nudged elastic band method with a Ni—Al—Re embedded-atom-method potential. A parameter (ΔE sf b ), the activation energy of SF nucleation under shear strain, is introduced to evaluate the effect of Re on SF nucleation under shear strain. Calculation results show that ΔE sf b decreases with Re addition, which means that SF nucleation under shear strain in Ni may be enhanced by Re. The atomic structure observation shows that the decrease of ΔE sf b may be due to the expansion of local structure around the Re atom when SF goes through the Re atom. (rapid communication)

  2. Stacking faults of {gamma}{prime}{prime} phase precipitated in a Ni-15Cr-8Fe-6Nb alloy; Ni-15Cr-8Fe-6Nb gokin ni sekishutsusuru {gamma}{prime}{prime} sonai no sekiso kekkan

    Energy Technology Data Exchange (ETDEWEB)

    Kusabiraki, K; Ikeuchi, S [Toyama University, Toyama (Japan). Faculty of Engineering

    1995-09-01

    The stacking faults of a metastable {gamma}{prime}{prime} phase precipitated in a nickel-base superalloy, a modified NCF 3 type alloy (X-750M) were investigated by transmission electron microscopy and X-ray diffraction method. The {gamma}{prime}{prime} precipitates are circular shaped plates at the early stage of aging and they become elliptic or irregular shaped plates at the latter stage of aging up to 1033K. Contrast which suggests the existence of stacking faults on {l_brace}112{r_brace}{sub {gamma}{prime}{prime}} planes can be seen in many of large {gamma}{prime}{prime} precipitates extracted from the specimens aged at 1033K. It is clear that the values of {gamma}{prime}{prime}/{gamma} lattice mismatch increase with increasing the aging time from the measurement of lattice constants of the {gamma} and the {gamma}{prime}{prime} phase. The formation of stacking faults on {l_brace}112{r_brace}{sub {gamma}{prime}{prime}} in the large {gamma}{prime}{prime} precipitates is due to the movement of an a/6 [111] partial dislocation introduced by {gamma}{prime}{prime} /{gamma} coherency strain. Since a part of stacking sequence has a similar crystal structure to that of a stable {delta} phase precipitates in {gamma} phase, the formation of stacking faults in the {gamma}{prime}{prime} precipitates is considered to be favorable for the stabilization of them. 14 refs., 10 figs., 1 tab.

  3. Reliable Fault Diagnosis of Rotary Machine Bearings Using a Stacked Sparse Autoencoder-Based Deep Neural Network

    Directory of Open Access Journals (Sweden)

    Muhammad Sohaib

    2018-01-01

    Full Text Available Due to enhanced safety, cost-effectiveness, and reliability requirements, fault diagnosis of bearings using vibration acceleration signals has been a key area of research over the past several decades. Many fault diagnosis algorithms have been developed that can efficiently classify faults under constant speed conditions. However, the performances of these traditional algorithms deteriorate with fluctuations of the shaft speed. In the past couple of years, deep learning algorithms have not only improved the classification performance in various disciplines (e.g., in image processing and natural language processing, but also reduced the complexity of feature extraction and selection processes. In this study, using complex envelope spectra and stacked sparse autoencoder- (SSAE- based deep neural networks (DNNs, a fault diagnosis scheme is developed that can overcome fluctuations of the shaft speed. The complex envelope spectrum made the frequency components associated with each fault type vibrant, hence helping the autoencoders to learn the characteristic features from the given input signals more readily. Moreover, the implementation of SSAE-DNN for bearing fault diagnosis has avoided the need of handcrafted features that are used in traditional fault diagnosis schemes. The experimental results demonstrate that the proposed scheme outperforms conventional fault diagnosis algorithms in terms of fault classification accuracy when tested with variable shaft speed data.

  4. Size effects of nano-spaced basal stacking faults on the strength and deformation mechanisms of nanocrystalline pure hcp metals

    Science.gov (United States)

    Wang, Wen; Jiang, Ping; Yuan, Fuping; Wu, Xiaolei

    2018-05-01

    The size effects of nano-spaced basal stacking faults (SFs) on the tensile strength and deformation mechanisms of nanocrystalline pure cobalt and magnesium have been investigated by a series of large-scale 2D columnar and 3D molecular dynamics simulations. Unlike the strengthening effect of basal SFs on Mg alloys, the nano-spaced basal SFs are observed to have no strengthening effect on the nanocrystalline pure cobalt and magnesium from MD simulations. These observations could be attributed to the following two reasons: (i) Lots of new basal SFs are formed before (for cobalt) or simultaneously with (for magnesium) the other deformation mechanisms (i.e. the formation of twins and the edge dislocations) during the tensile deformation; (ii) In hcp alloys, the segregation of alloy elements and impurities at typical interfaces, such as SFs, can stablilise them for enhancing the interactions with dislocation and thus elevating the strength. Without such segregation in pure hcp metals, the edge dislocations can cut through the basal SFs although the interactions between the dislocations and the pre-existing SFs/newly formed SFs are observed. The nano-spaced basal SFs are also found to have no restriction effect on the formation of deformation twins.

  5. Absolute age determination of quaternary fault and formation

    Energy Technology Data Exchange (ETDEWEB)

    Cheong, Chang Sik; Lee, Kwang Sik; Choi, Man Sik [Korea Basic Science Institute, Seoul (Korea, Republic of)] (and others)

    2002-04-15

    The annual ('01-'01) objective of this project is to data the fault activity for the presumed quaternary fault zones to the western part of the Ulsam fault system and southeastern coastal area near the Wolseong Nuclear Power Plant. Rb-Sr, K-Ar, OSL, C-14 and U-series disequilibrium methods were applied to the fault rocks, organic matter and quaternary formations collected from the Pyeonghae, Bogyeongsa, Yugyeri, Byegkye, Gacheon-1 and Joil outcrops of the Yangsan fault system, the Baenaegol outcrop of the Moryang fault system, the Susyongji(Madong-2), Singye, Hwalseongri, Ipsil and Wonwonsa outcrops of the Ulsan fault system and from quaternary marine terraces (Oryoo and Kwangseong sites) in the southeastern coastal area. The experimental procedure of the OSL SAR protocol was reexamined to get more reliable dating results.

  6. Local Conduction in MoxW1–xSe2: The Role of Stacking Faults, Defects, and Alloying

    Science.gov (United States)

    2018-01-01

    Here, we report on the surface conductivity of WSe2 and MoxW1–xSe2 (0 ≤ x ≤ 1) crystals investigated with conductive atomic force microscopy. We found that stacking faults, defects, and chemical heterogeneities form distinct two-dimensional and one-dimensional conduction paths on the transition metal dichalcogenide surface. In the case of WSe2, in addition to step edges, we find a significant amount of stacking faults (formed during the cleaving process) that strongly influence the surface conductivity. These regions are attributed to the alternation of the 2H and 3R polytypism. The stacking faults form regular 2D patterns by alternation of the underlying stacking order, with a periodicity that varies significantly between different regions and samples. In the case of MoxW1–xSe2, its conductivity has a localized nature, which depends on the underlying chemical composition and the Mo/W ratio. Segregation to W-rich and Mo-rich regions during the growth process leads to nonuniform conduction paths on the surface of the alloy. We found a gradual change of the conductivity moving from one region to the other, reminiscent of lateral band bending. Our results demonstrate the use of C-AFM as a nanoscopic tool to probe the electrical properties of largely inhomogeneous samples and show the complicated nature of the surface conductivity of TMDC alloys. PMID:29578328

  7. Local Conduction in Mo xW1- xSe2: The Role of Stacking Faults, Defects, and Alloying.

    Science.gov (United States)

    Bampoulis, Pantelis; Sotthewes, Kai; Siekman, Martin H; Zandvliet, Harold J W

    2018-04-18

    Here, we report on the surface conductivity of WSe 2 and Mo x W 1- x Se 2 (0 ≤ x ≤ 1) crystals investigated with conductive atomic force microscopy. We found that stacking faults, defects, and chemical heterogeneities form distinct two-dimensional and one-dimensional conduction paths on the transition metal dichalcogenide surface. In the case of WSe 2 , in addition to step edges, we find a significant amount of stacking faults (formed during the cleaving process) that strongly influence the surface conductivity. These regions are attributed to the alternation of the 2H and 3R polytypism. The stacking faults form regular 2D patterns by alternation of the underlying stacking order, with a periodicity that varies significantly between different regions and samples. In the case of Mo x W 1- x Se 2 , its conductivity has a localized nature, which depends on the underlying chemical composition and the Mo/W ratio. Segregation to W-rich and Mo-rich regions during the growth process leads to nonuniform conduction paths on the surface of the alloy. We found a gradual change of the conductivity moving from one region to the other, reminiscent of lateral band bending. Our results demonstrate the use of C-AFM as a nanoscopic tool to probe the electrical properties of largely inhomogeneous samples and show the complicated nature of the surface conductivity of TMDC alloys.

  8. Fault Localization Method by Partitioning Memory Using Memory Map and the Stack for Automotive ECU Software Testing

    Directory of Open Access Journals (Sweden)

    Kwanhyo Kim

    2016-09-01

    Full Text Available Recently, the usage of the automotive Electronic Control Unit (ECU and its software in cars is increasing. Therefore, as the functional complexity of such software increases, so does the likelihood of software-related faults. Therefore, it is important to ensure the reliability of ECU software in order to ensure automobile safety. For this reason, systematic testing methods are required that can guarantee software quality. However, it is difficult to locate a fault during testing with the current ECU development system because a tester performs the black-box testing using a Hardware-in-the-Loop (HiL simulator. Consequently, developers consume a large amount of money and time for debugging because they perform debugging without any information about the location of the fault. In this paper, we propose a method for localizing the fault utilizing memory information during black-box testing. This is likely to be of use to developers who debug automotive software. In order to observe whether symbols stored in the memory have been updated, the memory is partitioned by a memory map and the stack, thus the fault candidate region is reduced. A memory map method has the advantage of being able to finely partition the memory, and the stack method can partition the memory without a memory map. We validated these methods by applying these to HiL testing of the ECU for a body control system. The preliminary results indicate that a memory map and the stack reduce the possible fault locations to 22% and 19% of the updated memory, respectively.

  9. Stacking faults in Zr(Fe, Cr)2 Laves structured secondary phase particle in Zircaloy-4 alloy.

    Science.gov (United States)

    Liu, Chengze; Li, Geping; Yuan, Fusen; Han, Fuzhou; Zhang, Yingdong; Gu, Hengfei

    2018-02-01

    Stacking faults (SFs) in secondary phase particles (SPPs), which generally crystallize in the Laves phase in Zircaloy-4 (Zr-4) alloy, have been frequently observed by researchers. However, few investigations on the nano-scale structure of SFs have been carried out. In the present study, an SF containing C14 structured SPP, which located at grain boundaries (GBs) in the α-Zr matrix, was chosen to be investigated, for its particular substructure as well as location, aiming to reveal the nature of the SFs in the SPPs in Zr-4 alloy. It was indicated that the SFs in the C14 structured SPP actually existed in the local C36 structured Laves phase, for their similarities in crystallography. The C14 → C36 phase transformation, which was driven by synchroshearing among the (0001) basal planes, was the formation mechanism of the SFs in the SPPs. By analyzing the strained regions near the SPP, a model for understanding the driving force of the synchroshear was proposed: the interaction between SPP and GB resulted in the Zener pinning effect, leading to the shearing parallel to the (0001) basal planes of the C14 structured SPP, and the synchroshear was therefore activated.

  10. Effect of stacking fault energy on the neutron radiation induced defect accumulation in stainless steels

    International Nuclear Information System (INIS)

    Li Xiaoqiang; Al Mazouzi Abderrahim

    2009-01-01

    Current knowledge highlights the radiation induced segregation (RIS) and the radiation hardening as the two main effects on irradiation assisted stress corrosion cracking (IASCC). Stacking fault energy is considered as a key parameter of materials, which can influence IASCC of stainless steels in nuclear light water reactor (LWR), because it plays an important role in every process of plastic deformation, work hardening and creep behaviour. The study of the impact of SFE variations on the plastic deformation and SCC behaviour of irradiated and unirradiated austenitic steels will contribute to the understanding of IASCC mechanism. The objectives of this work, as a task within the FP6-European Project PERFECT, are to investigate the influence of the SFE on IASCC susceptibility of stainless steels, to correlation n-irradiation induced defect production, accumulation and mechanical deformation behaviour with SFE by using the state of the art experimental tools such as transmission electron microscope (TEM), positron annihilation spectroscopy (PAS), slow strain rate tests (SSRT) in simulated LWR conditions

  11. Stacking faults enriched silver nanowires: facile synthesis, catalysis and SERS investigations.

    Science.gov (United States)

    Xu, Minmin; Yang, Fengzhu; Yuan, Yaxian; Guo, Qinghua; Ren, Bin; Yao, Jianlin; Gu, Renao

    2013-10-01

    A facile approach based on seed-mediated method for synthesis of stacking faults enriched Ag nanowires (SFEANWs) was successfully developed. SFEANWs were formed and attached onto the seed (α-Fe2O3/Au) surfaces through the reduction of AgNO3 by ascorbic acid (AA) in the presence of sodium polyacrylate (PAANa). Their length can be tuned with different concentrations of AgNO3 or PAANa. According to the effects of seeds and PAANa, the plausible growth mechanism of SFEANWs was discussed. The catalytic activity of SFEANWs comparing with fivefold twinned Ag nanowires (FFTANWs) was evaluated through reducing p-nitrophenol by NaBH4. The activation energy of the classical reaction catalyzed by SFEANWs was calculated through the Arrhenius equation. In addition, these SFEANWs exhibited excellent surface enhanced Raman scattering (SERS) activities due to the hot spots located in the cross of the twist wires. The detection limit of by SERS for 1,4-benzenedithiol (1,4-BDT) was estimated about 10(-7) mol/L. Copyright © 2013 Elsevier Inc. All rights reserved.

  12. Influence of stacking fault energies on the size distribution and character of defect clusters formed by collision cascades in face-centered cubic metals

    Directory of Open Access Journals (Sweden)

    Y. Yang

    2016-12-01

    Full Text Available Molecular dynamics simulations are performed to evaluate the influence of the stacking fault energy (SFE as a single variable parameter on defect formation by collision cascades in face-centered cubic metals. The simulations are performed for energies of a primary knock-on atom (EPKA up to 50keV at 100K by using six sets of the recently developed embedded atom method–type potentials. Neither the number of residual defects nor their clustering behavior is found to be affected by the SFE, except for the mean size of the vacancy clusters at EPKA=50keV. The mean size increases as the SFE decreases because of the enhanced formation of large vacancy clusters, which prefer to have stacking faults inside them. On the other hand, the ratio of glissile self-interstitial atom (SIA clusters decreases as the SFE increases. At higher SFEs, both the number of Frank loops and number of perfect loops tend to decrease; instead, three-dimensional irregular clusters with higher densities appear, most of which are sessile. The effect of SFE on the number of Frank loops becomes apparent only at a high EPKA of 50keV, where comparably large SIA clusters can be formed with a higher density.

  13. The elastic properties, generalized stacking fault energy and dissociated dislocations in MgB2 under different pressure

    KAUST Repository

    Feng, Huifang

    2013-05-31

    The 〈112̄0〉 perfect dislocation in MgB2 is suggested to dissociate into two partial dislocations in an energy favorable way 〈112̄0〉 → 1/2 〈112̄0〉 + SF + 1/2 〈112̄0〉. This dissociation style is a correction of the previous dissociation 〈1000〉 → 1/3 〈11̄00〉 SF + 1/3 〈 2100〉proposed by Zhu et al. to model the partial dislocations and stacking fault observed by transmission electron microscopy. The latter dissociation results in a maximal stacking fault energy rather than a minimal one according to the generalized stacking fault energy calculated from first-principles methods. Furthermore, the elastic constants and anisotropy of MgB2 under different pressure are investigated. The core structures and mobilities of the 〈112̄0〉 dissociated dislocations are studied within the modified Peierls-Nabarro (P-N) dislocation theory. The variational method is used to solve the modified P-N dislocation equation and the Peierls stress is also determined under different pressure. High pressure effects on elastic anisotropy, core structure and Peierls stress are also presented. © 2013 Springer Science+Business Media New York.

  14. Structure of kaolinite and influence of stacking faults: reconciling theory and experiment using inelastic neutron scattering analysis.

    Science.gov (United States)

    White, Claire E; Kearley, Gordon J; Provis, John L; Riley, Daniel P

    2013-05-21

    The structure of kaolinite at the atomic level, including the effect of stacking faults, is investigated using inelastic neutron scattering (INS) spectroscopy and density functional theory (DFT) calculations. The vibrational dynamics of the standard crystal structure of kaolinite, calculated using DFT (VASP) with normal mode analysis, gives good agreement with the experimental INS data except for distinct discrepancies, especially for the low frequency modes (200-400 cm(-1)). By generating several types of stacking faults (shifts in the a,b plane for one kaolinite layer relative to the adjacent layer), it is seen that these low frequency modes are affected, specifically through the emergence of longer hydrogen bonds (O-H⋯O) in one of the models corresponding to a stacking fault of -0.3151a - 0.3151b. The small residual disagreement between observed and calculated INS is assigned to quantum effects (which are not taken into account in the DFT calculations), in the form of translational tunneling of the proton in the hydrogen bonds, which lead to a softening of the low frequency modes. DFT-based molecular dynamics simulations show that anharmonicity does not play an important role in the structural dynamics of kaolinite.

  15. Structure of fault stackings of molecular layers X-M-X in CdI2 polytypic crystals

    International Nuclear Information System (INIS)

    Palosz, B.; Przedmojski, J.

    1984-01-01

    The arrangements of molecular layers I-Cd-I, which may be regarded as 'faulted' for CdI 2 polytypic crystals, are analyzed. Tentative classification of faults into those which are intermediate structure between the basic polytypes 2H and 4H and faults occurring between different blocks of pure structure 4 H is proposed. The connection between some growth parameters and the structure of faults in CdI 2 crystals grown from solutions is discussed. It is shown that the geometrical classification of stacking faults used for layered inorganic crystals is not appropriate for the description of the faults existing in polytypic crystals of MX 2 type. The effect of weak external electric and magnetic fields on the polytypic structure of CdI 2 is analyzed. The experiments performed for several hundred of polytypes of CdI 2 showed that the external fields may, in some conditions, affect the organization of the polytypic structure of crystals very strongly. In particular, it was found that the external fields may change the period of polytype cells and that the relative number of hexagonal and rhombohedral polytypes differ very strongly for crystals grown in the absence and in the presence of external electric and magnetic fields. (author)

  16. Is there a relationship between the stacking fault character and the activated mode of plasticity of Fe-Mn-based austenitic steels?

    International Nuclear Information System (INIS)

    Idrissi, H.; Ryelandt, L.; Veron, M.; Schryvers, D.; Jacques, P.J.

    2009-01-01

    By changing the testing temperature, an austenitic Fe-Mn-Al-Si alloy presents either ε-martensite transformation or mechanical twinning during straining. In order to understand the nucleation and growth mechanisms involved in both phenomena, defects and particularly stacking faults, were characterized by transmission electron microscopy. It is observed that the character of the stacking faults also changes (from extrinsic to intrinsic) together with the temperature and the activated mode of plasticity.

  17. Absolute age determination of quaternary fault and formation

    Energy Technology Data Exchange (ETDEWEB)

    Cheong, Chang Sik; Lee, Kwang Sik; Choi, Man Sik [Korea Basic Science Institute, Taejon (Korea, Republic of)] (and others)

    2003-03-15

    Rb-Sr and K-Ar dating results for the fault rocks suggest the occurrence of recurrent fault activity around 80-95 Ma, 70 Ma, 50 Ma, 30 Ma and 23 Ma along the Yangsan fault zone. The apparent K-Ar ages tend to be older than Rb-Sr ages, probably indicating the effect of excess radiogenic Ar, which will be furthur investigated by Ar-Ar method. The OSL SAR protocol using 220 .deg. C cut-heat yields reproducible and stratigraphically consistent OSL ages ranging from 71 ka to 48 ka for beach deposits of the marine terrace No 2. The apparent OSL ages for the marine terrace No 3 range from 92 ka to 61 ka. These ages constrain the minimum age of the platform considering the underestimation effect resulted from deposition underwater. Therefore we regard the formation age of the terrace No 3 as MIS(Marine Isotopic Stage) 5c or 5e. Rb-Sr and K-Ar dating results for the fault rocks suggest the occurrence of recurrent fault activity around 40 Ma, 30 Ma and 23 Ma along the Ulsan fault zone. Relatively young (< 10 Ma) fault activities are recognized in the Oesa, Janghangri and Wonwonsa sites.

  18. Effects of alloying element and temperature on the stacking fault energies of dilute Ni-base superalloys.

    Science.gov (United States)

    Shang, S L; Zacherl, C L; Fang, H Z; Wang, Y; Du, Y; Liu, Z K

    2012-12-19

    A systematic study of stacking fault energy (γ(SF)) resulting from induced alias shear deformation has been performed by means of first-principles calculations for dilute Ni-base superalloys (Ni(23)X and Ni(71)X) for various alloying elements (X) as a function of temperature. Twenty-six alloying elements are considered, i.e., Al, Co, Cr, Cu, Fe, Hf, Ir, Mn, Mo, Nb, Os, Pd, Pt, Re, Rh, Ru, Sc, Si, Ta, Tc, Ti, V, W, Y, Zn, and Zr. The temperature dependence of γ(SF) is computed using the proposed quasistatic approach based on a predicted γ(SF)-volume-temperature relationship. Besides γ(SF), equilibrium volume and the normalized stacking fault energy (Γ(SF) = γ(SF)/Gb, with G the shear modulus and b the Burgers vector) are also studied as a function of temperature for the 26 alloying elements. The following conclusions are obtained: all alloying elements X studied herein decrease the γ(SF) of fcc Ni, approximately the further the alloying element X is from Ni on the periodic table, the larger the decrease of γ(SF) for the dilute Ni-X alloy, and roughly the γ(SF) of Ni-X decreases with increasing equilibrium volume. In addition, the values of γ(SF) for all Ni-X systems decrease with increasing temperature (except for Ni-Cr at higher Cr content), and the largest decrease is observed for pure Ni. Similar to the case of the shear modulus, the variation of γ(SF) for Ni-X systems due to various alloying elements is traceable from the distribution of (magnetization) charge density: the spherical distribution of charge density around a Ni atom, especially a smaller sphere, results in a lower value of γ(SF) due to the facility of redistribution of charges. Computed stacking fault energies and the related properties are in favorable accord with available experimental and theoretical data.

  19. Characterization of double Shockley-type stacking faults formed in lightly doped 4H-SiC epitaxial films

    Science.gov (United States)

    Yamashita, T.; Hayashi, S.; Naijo, T.; Momose, K.; Osawa, H.; Senzaki, J.; Kojima, K.; Kato, T.; Okumura, H.

    2018-05-01

    Double Shockley-type stacking faults (2SSFs) formed in 4H-SiC epitaxial films with a dopant concentration of 1.0 × 1016 cm-3 were characterized using grazing incident X-ray topography and high-resolution scanning transmission electron microscopy. The origins of 2SSFs were investigated, and it was found that 2SSFs in the epitaxial layer originated from narrow SFs with a double Shockley structure in the substrate. Partial dislocations formed between 4H-type and 2SSF were also characterized. The shapes of 2SSFs are related with Burgers vectors and core types of the two Shockley partial dislocations.

  20. The impedance of inductive superconducting fault current limiters operating with stacks of thin film Y123/Au washers or bulk Bi2223 rings as secondaries

    International Nuclear Information System (INIS)

    Fernandez, J A Lorenzo; Osorio, M R; Toimil, P; Ferro, G; Blanch, M; Veira, J A; Vidal, F

    2006-01-01

    Inductive fault current limiters operating with stacks of various small superconducting elements acting as secondaries were studied. The stacks consist of Y 1 Ba 2 Cu 3 O 7-δ thin film washers or Bi 1.8 Pb 0.26 Sr 2 Ca 2 Cu 3 O 10+x bulk rings. A central result of our work is an experimental demonstration that the limiting capability of the device is strongly reduced when several bulk rings are stacked, whereas it remains almost unchanged for thin film washers. The use of thin films should therefore allow us to build more efficient high power inductive limiters based on stacks of small washers

  1. Breakdown of Shape Memory Effect in Bent Cu-Al-Ni Nanopillars: When Twin Boundaries Become Stacking Faults.

    Science.gov (United States)

    Liu, Lifeng; Ding, Xiangdong; Sun, Jun; Li, Suzhi; Salje, Ekhard K H

    2016-01-13

    Bent Cu-Al-Ni nanopillars (diameters 90-750 nm) show a shape memory effect, SME, for diameters D > 300 nm. The SME and the associated twinning are located in a small deformed section of the nanopillar. Thick nanopillars (D > 300 nm) transform to austenite under heating, including the deformed region. Thin nanopillars (D faults in the deformed region. No SME occurs and heating converts only the undeformed regions into austenite. The defect-rich, deformed region remains in the martensite phase even after prolonged heating in the stability field of austenite. A complex mixture of twins and stacking faults was found for diameters 130 nm < D < 300 nm. The size effect of the SME in Cu-Al-Ni nanopillars consists of an approximately linear reduction of the SME between 300 and 130 nm when the SME completely vanishes for smaller diameters.

  2. Characterization of individual stacking faults in a wurtzite GaAs nanowire by nanobeam X-ray diffraction.

    Science.gov (United States)

    Davtyan, Arman; Lehmann, Sebastian; Kriegner, Dominik; Zamani, Reza R; Dick, Kimberly A; Bahrami, Danial; Al-Hassan, Ali; Leake, Steven J; Pietsch, Ullrich; Holý, Václav

    2017-09-01

    Coherent X-ray diffraction was used to measure the type, quantity and the relative distances between stacking faults along the growth direction of two individual wurtzite GaAs nanowires grown by metalorganic vapour epitaxy. The presented approach is based on the general property of the Patterson function, which is the autocorrelation of the electron density as well as the Fourier transformation of the diffracted intensity distribution of an object. Partial Patterson functions were extracted from the diffracted intensity measured along the [000\\bar{1}] direction in the vicinity of the wurtzite 00\\bar{1}\\bar{5} Bragg peak. The maxima of the Patterson function encode both the distances between the fault planes and the type of the fault planes with the sensitivity of a single atomic bilayer. The positions of the fault planes are deduced from the positions and shapes of the maxima of the Patterson function and they are in excellent agreement with the positions found with transmission electron microscopy of the same nanowire.

  3. Influence of addition elements on the stacking-fault energy and mechanical properties of an austenitic Fe-Mn-C steel

    International Nuclear Information System (INIS)

    Dumay, A.; Chateau, J.-P.; Allain, S.; Migot, S.; Bouaziz, O.

    2008-01-01

    We present a thermochemical model of the stacking-fault energy (SFE) in the Fe-Mn-C system with few percent of Cu, Cr, Al and Si in addition. Aluminium strongly increases the SFE, contrary to chromium, while the effect of silicon is more complex. Copper also increases the SFE, but strongly decreases the Neel temperature. The SFE is the relevant parameter that controls mechanical twinning, which is known to be at the origin of the excellent mechanical properties of these steels. Using this model, copper containing Fe-Mn-C grades were elaborated with SFE below 18 mJ/m 2 , in the range where ε-martensite platelets form instead of microtwins during plastic deformation. This substitution of deformation modes, confirmed by X-ray diffraction, does not significantly damage the mechanical properties, as long as the SFE is greater than 12 mJ/m 2 , which avoids the formation of α'-martensite

  4. Flat-Top and Stacking-Fault-Free GaAs-Related Nanopillars Grown on Si Substrates

    Directory of Open Access Journals (Sweden)

    Kouta Tateno

    2012-01-01

    Full Text Available The VLS (vapor-liquid-solid method is one of the promising techniques for growing vertical III-V compound semiconductor nanowires on Si for application to optoelectronic circuits. Heterostructures grown in the axial direction by the VLS method and in the radial direction by the general layer-by-layer growth method make it possible to fabricate complicated and functional three-dimensional structures in a bottom-up manner. We can grow some vertical heterostructure nanopillars with flat tops on Si(111 substrates, and we have obtained core-multishell Ga(InP/GaAs/GaP nanowires with flat tops and their air-gap structures by using selective wet etching. Simulations indicate that a high- factor of over 2000 can be achieved for this air-gap structure. From the GaAs growth experiments, we found that zincblende GaAs without any stacking faults can be grown after the GaP nanowire growth. Pillars containing a quantum dot and without stacking faults can be grown by using this method. We can also obtain flat-top pillars without removing the Au catalysts when using small Au particles.

  5. First principle study on generalized-stacking-fault energy surfaces of B2-AlRE intermetallic compounds

    Science.gov (United States)

    Li, Shaorong; Wang, Shaofeng; Wang, Rui

    2011-12-01

    First-principles calculations are used to predict the generalized-stacking-fault energy (GSFE) surfaces of AlRE intermetallics. The calculations employ the projector augmented-wave (PAW) method within the generalized gradient approximation (GGA) using the density functional theory (DFT). GSFE curves along {1 1 0} direction, {1 1 0} direction and {1 1 0} direction have been calculated. The fitted GSFE surfaces have been obtained from the Fourier series based on the translational symmetry. In order to illuminate the reasonable of our computational accuracy, we have compared our theoretical results of B2 intermetallics YCu with the previous calculated results. The unstable-stacking-fault energy (γus) on the {1 1 0} plane has the laws of AlPr, and directions. For the antiphase boundary (APB) energy, that of AlSc is the lowest in the calculated AlRE intermetallics. So the superdislocation with the Burgers vector along direction of AlSc will easily split into two superpartials.

  6. Significant contribution of stacking faults to the strain hardening behavior of Cu-15%Al alloy with different grain sizes.

    Science.gov (United States)

    Tian, Y Z; Zhao, L J; Chen, S; Shibata, A; Zhang, Z F; Tsuji, N

    2015-11-19

    It is commonly accepted that twinning can induce an increase of strain-hardening rate during the tensile process of face-centered cubic (FCC) metals and alloys with low stacking fault energy (SFE). In this study, we explored the grain size effect on the strain-hardening behavior of a Cu-15 at.%Al alloy with low SFE. Instead of twinning, we detected a significant contribution of stacking faults (SFs) irrespective of the grain size even in the initial stage of tensile process. In contrast, twinning was more sensitive to the grain size, and the onset of deformation twins might be postponed to a higher strain with increasing the grain size. In the Cu-15 at.%Al alloy with a mean grain size of 47 μm, there was a stage where the strain-hardening rate increases with strain, and this was mainly induced by the SFs instead of twinning. Thus in parallel with the TWIP effect, we proposed that SFs also contribute significantly to the plasticity of FCC alloys with low SFE.

  7. On the measurement of the stacking-fault energies of face centered cubic metal and austenitic stainless steels by X-ray diffraction

    International Nuclear Information System (INIS)

    Borges, J.F.A.

    1985-01-01

    An X-rays diffraction method was applied to measure the Stacking-Fault Energies (SFE) of the AISI 304, AISI 316, AISI 347 and DIN-WERKSTOFF 1.4970 Austenitic Stainless Steels. The SFE determination plays an important role in the research of the mechanical behaviour of the Metal and Alloys, their deformation mechanisms, stability of microstructure amd electronic configuration. The method is based on the relationship between the SFE and the ratio of the Mean Square Strain to the Stacking-Fault probability. The Mean Square Strain was evaluated by Fourier Analysis of X-rays Diffraction profiles, corrected to reduce instrumental effects, followed by the application of the Warren-Averbach method to the Fourier Coefficients. The Stacking-Fault probabilities were derived from the changes of peak separations between cold-worked and annealed specimens. (author) [pt

  8. Morphology of single Shockley-type stacking faults generated by recombination enhanced dislocation glide in 4H-SiC

    Science.gov (United States)

    Matsuhata, Hirofumi; Sekiguchi, Takashi

    2018-04-01

    Morphology of single Shockley-type stacking faults (SFs) generated by recombination enhanced dislocation glide (REDG) in 4H-SiC are discussed and analysed. A complete set of the 12 different dissociated states of basal-plane dislocation loops is obtained using the crystallographic space group operations. From this set, six different double rhombic-shaped SFs are derived. These tables indicate the rules that connect shapes of SFs with the locations of partial dislocations having different core structures, the positions of slip planes in a unit cell, and the Burgers vectors of partial dislocations. We applied these tables for the analysis of SFs generated by the REDG effect reported in the past articles. Shapes, growing process of SFs and perfect dislocations for origins of SFs were well analysed systematically.

  9. Stacking fault density as engineering criterion for resistance to radiation swelling of alloys' FCC- and BCC-lattice

    International Nuclear Information System (INIS)

    Zheltov, Yu.V.; Ageev, V.S.; Kolesnikov, Yu.G.

    1990-01-01

    The experimental data on influence of Mn, Cr, Ni, P, B, Ce alloying in austenitic and simultaneously Nb, V, B alloying in ferritic steels and also heat treatment on stacking fault density (SFD) are represented. In all cases besides influence of Cr in austenitic steel the increase of SFD is shown. The decrease of radiation swelling of industrial steels at the increase of their SFD, measured by X-rays, was studied. The tendency of increase of relative radiation swelling change at SFD increase at relative fluence rise is verified. It is shown that SFD may be a perspective proximate characteristics of choice of radiation-resistant steel melts within one steel quality. 14 refs.; 4 figs. (author)

  10. Effect of a High Density of Stacking Faults on the Young's Modulus of GaAs Nanowires.

    Science.gov (United States)

    Chen, Yujie; Burgess, Tim; An, Xianghai; Mai, Yiu-Wing; Tan, H Hoe; Zou, Jin; Ringer, Simon P; Jagadish, Chennupati; Liao, Xiaozhou

    2016-03-09

    Stacking faults (SFs) are commonly observed crystalline defects in III-V semiconductor nanowires (NWs) that affect a variety of physical properties. Understanding the effect of SFs on NW mechanical properties is critical to NW applications in nanodevices. In this study, the Young's moduli of GaAs NWs with two distinct structures, defect-free single crystalline wurtzite (WZ) and highly defective wurtzite containing a high density of SFs (WZ-SF), are investigated using combined in situ compression transmission electron microscopy and finite element analysis. The Young's moduli of both WZ and WZ-SF GaAs NWs were found to increase with decreasing diameter due to the increasing volume fraction of the native oxide shell. The presence of a high density of SFs was further found to increase the Young's modulus by 13%. This stiffening effect of SFs is attributed to the change in the interatomic bonding configuration at the SFs.

  11. Modeling defects and plasticity in MgSiO3 post-perovskite: Part 1-generalized stacking faults.

    Science.gov (United States)

    Goryaeva, Alexandra M; Carrez, Philippe; Cordier, Patrick

    In this work, we examine the transferability of a pairwise potential model (derived for MgSiO 3 perovskite) to accurately compute the excess energies of the generalized stacking faults (GSF, also called γ -surfaces) in MgSiO 3 post-perovskite. All calculations have been performed at 120 GPa, a pressure relevant to the D″ layer. Taking into account an important aspect of crystal chemistry for complex materials, we consider in detail all possible locations of slip planes in the post-perovskite structure. The γ -surface calculations emphasize the easiness of glide of slip systems with the smallest shear vector [100] and of the [001](010) slip system. Our results are in agreement with previous ab initio calculations. This validates the use the chosen potential model for further full atomistic modeling of dislocations in MgSiO 3 post-perovskite.

  12. Formation of long-period stacking ordered structures in Mg88M5Y7 (M = Ti, Ni and Pb) casting alloys

    International Nuclear Information System (INIS)

    Jin, Qian-Qian; Fang, Can-Feng; Mi, Shao-Bo

    2013-01-01

    Highlights: •Apart from 18R-LPSO, 14H-LPSO structure was determined in the Mg-Ni-Y alloys. •The appearance of twin-related structure in 18R-LPSO structure results from the stacking faults in the stacking sequence of the closely packed planes. •A new (Pb, Mg) 2 Y phase with a body-centered orthorhombic structure was determined in the Mg-Pb-Y alloy. •No LPSO structures were found in the Mg-Pb-Y and Mg-Ti-Y casting alloys. -- Abstract: Formation of long-period stacking ordered (LPSO) structures is investigated in Mg 88 M 5 Y 7 (M = Ti, Ni and Pb) casting alloys by means of electron microscopy and X-ray diffraction. In the Mg 88 Ni 5 Y 7 casting alloy, 14H-LPSO structure is observed in a small amount, which coexists with 18R-LPSO structure. The appearance of stacking faults in 18R-LPSO structure results in twin-related structure in the stacking sequence of the closely packed planes. A new (Pb, Mg) 2 Y phase with a body-centered orthorhombic structure is determined in the Mg 88 Pb 5 Y 7 alloy. No LPSO structures are found in the Mg 88 Pb 5 Y 7 and Mg 88 Ti 5 Y 7 casting alloys. In terms of the atomic radius and heat of mixing, the formation ability of LPSO structure in the present alloys is discussed

  13. Role of stacking fault energy on the deformation characteristics of copper alloys processed by plane strain compression

    International Nuclear Information System (INIS)

    El-Danaf, Ehab A.; Al-Mutlaq, Ayman; Soliman, Mahmoud S.

    2011-01-01

    Highlights: → Different compositions of Cu-Zn and Cu-Al alloys are plane strain compressed. → Strain hardening rates, microstructure and texture evolution are documented. → SFE has an indirect effect rather a critical dislocation density controls twinning. → Cu-Al exhibited the need for higher dislocation density for twin initiation. → Onset of twinning occurs in the copper alloys tested with a normalized SFE ≤ 10-3. - Abstract: Samples of Cu-Al and Cu-Zn alloys with different compositions were subjected to large strains under plane strain compression (PSC), a process that simulates the rolling operation. Four compositions in the Cu-Al system, namely 1, 2, 4.7 and 7 wt.% Al and three compositions in the Cu-Zn system of 10, 20 and 30 wt.% Zn, were investigated. Adding Al or Zn to Cu effectively lowers the stacking fault energy (SFE) of the alloy and changes the deformation mechanism from dislocation slipping to dislocation slipping and deformation twinning. True stress-true strain responses in PSC were documented and the strain hardening rates were calculated and correlated to the evolved microstructure. The onset of twinning in low SFE alloys was not directly related to the low value of SFE, but rather to build up of a critical dislocation density during strain hardening in the early stage of deformation (ε < 0.1). The evolution of texture was documented for the Cu-Al samples using X-ray diffraction for samples plane strain compressed to true axial strains of 0.25, 0.5, 0.75 and 1.0. Orientation distribution function (ODF) plots were generated and quantitative information on the volume fraction of ideal rolling orientations were depicted and correlated with the stacking fault energy.

  14. Influence of basal-plane dislocation structures on expansion of single Shockley-type stacking faults in forward-current degradation of 4H-SiC p-i-n diodes

    Science.gov (United States)

    Hayashi, Shohei; Yamashita, Tamotsu; Senzaki, Junji; Miyazato, Masaki; Ryo, Mina; Miyajima, Masaaki; Kato, Tomohisa; Yonezawa, Yoshiyuki; Kojima, Kazutoshi; Okumura, Hajime

    2018-04-01

    The origin of expanded single Shockley-type stacking faults in forward-current degradation of 4H-SiC p-i-n diodes was investigated by the stress-current test. At a stress-current density lower than 25 A cm-2, triangular stacking faults were formed from basal-plane dislocations in the epitaxial layer. At a stress-current density higher than 350 A cm-2, both triangular and long-zone-shaped stacking faults were formed from basal-plane dislocations that converted into threading edge dislocations near the interface between the epitaxial layer and the substrate. In addition, the conversion depth of basal-plane dislocations that expanded into the stacking fault was inside the substrate deeper than the interface. These results indicate that the conversion depth of basal-plane dislocations strongly affects the threshold stress-current density at which the expansion of stacking faults occurs.

  15. Effects of stacking fault energies on the interaction between an edge dislocation and an 8.0-nm-diameter Frank loop of self-interstitial atoms

    Directory of Open Access Journals (Sweden)

    S. Hayakawa

    2016-12-01

    Full Text Available Molecular dynamics simulations were conducted to investigate the effects of stacking fault energy (SFE as a single variable parameter on the interaction between an edge dislocation and a Frank loop of self-interstitial atoms with a diameter of 8.0nm. The physical contact between the edge dislocation and the loop causes constriction of the edge dislocation, followed by the formation of a D-Shockley partial dislocation. The latter process is associated with either the formation of a screw component and its cross-slip, or the direct core reaction between the dislocation and the loop. These processes induce either the absorption of the loop into the dislocation or the transformation of the loop into a perfect loop. The SFE influences the interaction morphologies by determining the separation distance of the two partial dislocations and consequently the rate of constriction. The dependence of the interaction morphology on the SFE varies with the habit plane of the loop. A higher SFE increases the probability of the absorption or transformation interaction; however, only loop shearing is observed at the lower limit of the SFE range of austenitic stainless steels.

  16. Yttrium scandate thin film as alternative high-permittivity dielectric for germanium gate stack formation

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Cimang, E-mail: cimang@adam.t.u-tokyo.ac.jp; Lee, Choong Hyun; Nishimura, Tomonori; Toriumi, Akira [Department of Materials Engineering, The University of Tokyo, 7-3-1 Hongo, Tokyo 113-8656 (Japan); JST, CREST, 7-3-1 Hongo, Tokyo 113-8656 (Japan)

    2015-08-17

    We investigated yttrium scandate (YScO{sub 3}) as an alternative high-permittivity (k) dielectric thin film for Ge gate stack formation. Significant enhancement of k-value is reported in YScO{sub 3} comparing to both of its binary compounds, Y{sub 2}O{sub 3} and Sc{sub 2}O{sub 3}, without any cost of interface properties. It suggests a feasible approach to a design of promising high-k dielectrics for Ge gate stack, namely, the formation of high-k ternary oxide out of two medium-k binary oxides. Aggressive scaling of equivalent oxide thickness (EOT) with promising interface properties is presented by using YScO{sub 3} as high-k dielectric and yttrium-doped GeO{sub 2} (Y-GeO{sub 2}) as interfacial layer, for a demonstration of high-k gate stack on Ge. In addition, we demonstrate Ge n-MOSFET performance showing the peak electron mobility over 1000 cm{sup 2}/V s in sub-nm EOT region by YScO{sub 3}/Y-GeO{sub 2}/Ge gate stack.

  17. The effect of impurity level on ultrafine-grained microstructures and their stability in low stacking fault energy silver

    International Nuclear Information System (INIS)

    Hegedus, Zoltan; Gubicza, Jeno; Kawasaki, Megumi; Chinh, Nguyen Q.; Fogarassy, Zsolt; Langdon, Terence G.

    2011-01-01

    Highlights: → Effect of impurity content on microstructure in ECAP-processed silver was studied. → There is a lower degree of twinning in the less pure material for high strains. → The samples processed for 4-16 passes showed self-annealing during storage at RT. → Small increase of impurity level resulted in a much better stability at RT. - Abstract: The effect of impurity content on the evolution of microstructure in low stacking fault energy silver processed by severe plastic deformation (SPD) was studied. The SPD-processing was carried out on 4N5 and 4N purity Ag samples by equal-channel angular pressing (ECAP) up to 16 passes. It was found that, although the minimum grain size and the maximum dislocation density were not affected by the different impurity atom content, there is a lower degree of twinning in the less pure material for high number of passes. The small increase of impurity level from 4N5 to 4N in Ag resulted in a significantly better thermal stability at room temperature for the ultrafine-grained microstructures obtained by ECAP.

  18. Expansion of Shockley stacking fault observed by scanning electron microscope and partial dislocation motion in 4H-SiC

    Science.gov (United States)

    Yamashita, Yoshifumi; Nakata, Ryu; Nishikawa, Takeshi; Hada, Masaki; Hayashi, Yasuhiko

    2018-04-01

    We studied the dynamics of the expansion of a Shockley-type stacking fault (SSF) with 30° Si(g) partial dislocations (PDs) using a scanning electron microscope. We observed SSFs as dark lines (DLs), which formed the contrast at the intersection between the surface and the SSF on the (0001) face inclined by 8° from the surface. We performed experiments at different electron-beam scanning speeds, observing magnifications, and irradiation areas. The results indicated that the elongation of a DL during one-frame scanning depended on the time for which the electron beam irradiated the PD segment in the frame of view. From these results, we derived a formula to express the velocity of the PD using the elongation rate of the corresponding DL during one-frame scanning. We also obtained the result that the elongation velocity of the DL was not influenced by changing the direction in which the electron beam irradiates the PD. From this result, we deduced that the geometrical kink motion of the PD was enhanced by diffusing carriers that were generated by the electron-beam irradiation.

  19. Mechanical and structural behaviour of high stacking fault energy materials submitted to large hot deformation

    International Nuclear Information System (INIS)

    Montheillet, F.

    1981-01-01

    The dynamic recovery process is described and compared with dynamic recrystallization, particularly at very large strains obtained by torsion tests. The stress-strain curves are first examined and related to the evolution of the microstructure, consisting essentially of a continuous increase in the misorientation between neighbouring crystals. The relations between the flow stress and the size of crystals are then described. Finally, it is shown that the shear undergone during torsion induces the formation of a strong crystallographic texture [fr

  20. The use of pattern decomposition to study the combined X-ray diffraction effects of crystallite size and stacking faults in ex-oxalate zinc oxide

    International Nuclear Information System (INIS)

    Langford, J.I.; Boultif, A.; Auffredic, J.P.; Louer, D.

    1993-01-01

    The microstructure of ZnO powder, obtained from thermal decomposition of the oxalate and studied previously by electron microscopy and adsorption calorimetry, was investigated by means of X-ray powder diffraction pattern decomposition. A Williamson-Hall plot revealed that some lines were broadened solely due to the effects of crystallite size, whereas other breadths included a contribution due to stacking faults. Spherical and cylindrical models are used to describe the form of the crystallites and procedures are presented for separating 'size' effects from 'mistake' broadening. This leads to estimates of the mean dimensions of the crystallites and the stacking-fault probability. The analysis demonstrates that, with good-quality data for a large number of reflections, a considerable amount of detailed information can be obtained about microstructure. On the other hand, it reveals some of the limitations of current procedures for modelling diffraction line profiles. (orig.)

  1. Enhanced photocatalytic activity over Cd{sub 0.5}Zn{sub 0.5}S with stacking fault structure combined with Cu{sup 2+} modified carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Beini; Lu, Yonghong [School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006 (China); The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006 (China); Wu, Pingxiao, E-mail: pppxwu@scut.edu.cn [School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006 (China); The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006 (China); Guangdong Provincial Engineering and Technology Research Centre for Environment Risk Prevention and Emergency Disposal, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006 (China); Huang, Zhujian; Zhu, Yajie; Dang, Zhi [School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006 (China); The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006 (China); Zhu, Nengwu [School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006 (China); The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006 (China); Guangdong Provincial Engineering and Technology Research Centre for Environment Risk Prevention and Emergency Disposal, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006 (China); Lu, Guining; Huang, Junyi [School of Environment and Energy, South China University of Technology, Guangzhou Higher Education Mega Centre, Guangzhou 510006 (China); The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006 (China)

    2016-03-01

    Graphical abstract: - Highlights: • CdZnS with stacking faults was combined with Cu{sup 2+} modified carbon nanotubes. • Stacking faults and carbon nanotubes (Cu) synergized to promote charge separation. • The composite exhibited enhanced photocatalytic performance. - Abstract: For enhanced photocatalytic performance of visible light responsive CdZnS, a series of Cd{sub 0.5}Zn{sub 0.5}S solid solutions were fabricated by different methods. It was found that the semiconductor obtained through the precipitation-hydrothermal method (CZS-PH) exhibited the highest photocatalytic hydrogen production rate of 2154 μmol h{sup −1} g{sup −1}. The enhanced photocatalytic hydrogen production of CZS-PH was probably due to stacking fault formation as well as narrow bandgap, a large surface area and a small crystallite size. Based on this, carbon nanotubes modified with Cu{sup 2+} (CNTs (Cu)) were used as a cocatalyst for CZS-PH. The addition of CNTs (Cu) enhanced notably the absorption of the composites for visible light. The highest photocatalytic hydrogen production rate of the Cd{sub 0.5}Zn{sub 0.5}S-CNTs (Cu) composite was 2995 μmol h{sup −1} g{sup −1} with 1.0 wt.% of CNTs (Cu). The improvement of the photocatalytic activity by loading of CNTs (Cu) was not due to alteration of bandgap energy or surface area, and was probably attributed to suppression of the electron-hole recombination by the CNTs, with Cu{sup 2+} anchored in the interface optimizing the photogenerated electron transfer pathway between the semiconductor and CNTs. We report here the successful combination of homojunction and heterojunction in CdZnS semiconductor, which resulted in promotion of charge separation and enhanced photocatalytic activity.

  2. Generalized-stacking-fault energy and twin-boundary energy of hexagonal close-packed Au: A first-principles calculation.

    Science.gov (United States)

    Wang, Cheng; Wang, Huiyuan; Huang, Tianlong; Xue, Xuena; Qiu, Feng; Jiang, Qichuan

    2015-05-22

    Although solid Au is usually most stable as a face-centered cubic (fcc) structure, pure hexagonal close-packed (hcp) Au has been successfully fabricated recently. However, the phase stability and mechanical property of this new material are unclear, which may restrict its further applications. Here we present the evidence that hcp → fcc phase transformation can proceed easily in Au by first-principles calculations. The extremely low generalized-stacking-fault (GSF) energy in the basal slip system implies a great tendency to form basal stacking faults, which opens the door to phase transformation from hcp to fcc. Moreover, the Au lattice extends slightly within the superficial layers due to the self-assembly of alkanethiolate species on hcp Au (0001) surface, which may also contribute to the hcp → fcc phase transformation. Compared with hcp Mg, the GSF energies for non-basal slip systems and the twin-boundary (TB) energies for and twins are larger in hcp Au, which indicates the more difficulty in generating non-basal stacking faults and twins. The findings provide new insights for understanding the nature of the hcp → fcc phase transformation and guide the experiments of fabricating and developing materials with new structures.

  3. Formation of an 18R long-period stacking ordered structure in rapidly solidified Mg88Y8Zn4 alloy

    International Nuclear Information System (INIS)

    Garcés, Gerardo; Requena, Guillermo; Tolnai, Domonkos; Pérez, Pablo; Medina, Judit; Stark, Andreas; Schell, Norbert; Adeva, Paloma

    2016-01-01

    The formation of the long-period stacking ordered structure (LPSO) in a Mg 88 Y 8 Zn 4 (at%) ribbon produced by melt spinning was studied using high energy X-ray synchrotron radiation diffraction during in-situ isochronal heating and transmission electron microscopy. The microstructure of the rapidly solidified ribbons is characterised by fine magnesium grains with yttrium and zinc in solid solution and primary 18R LPSO-phase segregated at grain boundaries. Using differential scanning calorimetry, a strong exothermal peak was observed around 300 °C which was associated with the development of the 18R-type LPSO-phase in the magnesium grains. The apparent activation energy calculated using the Kissinger model was 125 KJmol −1 and it is related to simultaneous diffusion of Y and Zn through magnesium basal plane. - Highlights: •The formation of the LPSO phase in rapidly solidified ribbons was studied. •The formation of the 18R LPSO starts at around 300 °C. •LPSO formation have to steps: Stacking faults along basal plane and then growth of 18R structure along the c direction.

  4. Stacking Faults and Polytypes for Layered Double Hydroxides: What Can We Learn from Simulated and Experimental X-ray Powder Diffraction Data?

    Science.gov (United States)

    Sławiński, Wojciech A; Sjåstad, Anja Olafsen; Fjellvåg, Helmer

    2016-12-19

    Layered double hydroxides (LDH) are a broad group of widely studied materials. The layered character of those materials and their high flexibility for accommodating different metals and anions make them technologically interesting. The general formula for the LDH compound is [M 1-x II M x III (OH) 2 ][A n- ] x/n ·mH 2 O, where M II is a divalent metal cation which can be substituted by M III trivalent cation, and A n- is a charge compensating anion located between positively charged layers. In this paper we present a comprehensive study on possible structural disorder in LDH. We show how X-ray powder diffraction (XRPD) can be used to reveal important features of the LDH crystal structure such as stacking faults, random interlayer shifts, anion-molecule orientation, crystal water content, distribution of interlayer distances, and also LDH slab thickness. All calculations were performed using the Discus package, which gives a better flexibility in defining stacking fault sequences, simulating and refining XRPD patterns, relative to DIFFaX, DIFFaX+, and FAULTS. Finally, we show how the modeling can be applied to two LDH samples: Ni 0.67 Cr 0.33 (OH) 2 (CO 3 ) 0.16 ·mH 2 O (3D structure) and Mg 0.67 Al 0.33 (OH) 2 (NO 3 ) 0.33 (2D layered structure).

  5. Generalized stacking fault energies, cleavage energies, ionicity and brittleness of Cu(Al/Ga/In)Se2 and CuGa(S/Se/Te)2

    Science.gov (United States)

    Xue, H. T.; Tang, F. L.; Gruhn, T.; Lu, W. J.; Wan, F. C.; Rui, Z. Y.; Feng, Y. D.

    2014-04-01

    We calculate the generalized stacking fault (GSF) energies and cleavage energies γcl of the chalcopyrite compounds CuAlSe2, CuGaSe2, CuInSe2, CuGaS2 and CuGaTe2 using first principles. From the GSF energies, we obtain the unstable stacking fault energies γus and intrinsic stacking fault energies γisf. By analyzing γus and γisf, we find that the \\langle \\bar{{1}}\\,1\\,0\\rangle (1 1 2) direction is the easiest slip direction for these five compounds. Also, for CuInSe2, it is most possible to undergo a dislocation-nucleation-induced plastic deformation along the \\langle \\bar{{1}}\\,1\\,0\\rangle (1 1 2) slip direction. We show that the (1 1 2) plane is the preferable plane for fracture in the five compounds by comparing γcl of the (0 0 1) and (1 1 2) planes. It is also found that both γus and γcl decrease as the cationic or anionic radius increases in these chalcopyrites, i.e. along the sequences CuAlSe2 → CuGaSe2 → CuInSe2 and CuGaS2 → CuGaSe2 → CuGaTe2. Based on the values of the ratio γcl/γus, we discuss the brittle-ductile properties of these compounds. All of the compounds can be considered as brittle materials. In addition, a strong relationship between γcl/γus and the total proportion of ionic bonding in these compounds is found.

  6. Fault-Tolerant Precision Formation Guidance for Interferometry, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — A methodology is to be developed that will allow the development and implementation of fault-tolerant control system for distributed collaborative spacecraft. The...

  7. Multi-scale investigation into the mechanisms of fault mirror formation in seismically active carbonate rocks

    Science.gov (United States)

    Ohl, Markus; Chatzaras, Vasileios; Niemeijer, Andre; King, Helen; Drury, Martyn; Plümper, Oliver

    2017-04-01

    Mirror surfaces along principal slip zones in carbonate rocks have recently received considerable attention as they are thought to form during fault slip at seismic velocities and thus may be a marker for paleo-seismicity (Siman-Tov et al., 2013). Therefore, these structures represent an opportunity to improve our understanding of earthquake mechanics in carbonate faults. Recent investigations reported the formation of fault mirrors in natural rocks as well as in laboratory experiments and connected their occurrence to the development of nano-sized granular material (Spagnuolo et al., 2015). However, the underlying formation and deformation mechanisms of these fault mirrors are still poorly constrained and warrant further research. In order to understand the influence and significance of these fault products on the overall fault behavior, we analysed the micro-, and nanostructural inventory of natural fault samples containing mirror slip surfaces. Here we present first results on the possible formation mechanisms of fault mirrors and associated deformation mechanisms operating in the carbonate fault gouge from two seismically active fault zones in central Greece. Our study specifically focuses on mirror slip surfaces obtained from the Arkitsa fault in the Gulf of Evia and the Schinos fault in the Gulf of Corinth. The Schinos fault was reactivated by a magnitude 6.7 earthquake in 1981 while the Arkitsa fault is thought to have been reactivated by a magnitude 6.9 earthquake in 1894. Our investigations encompass a combination of state-of-the-art analytical techniques including X-ray computed tomography, focused ion beam scanning electron microscopy (FIB-SEM), transmission electron microscopy (TEM) and Raman spectroscopy. Using this multiscale analytical approach, we report decarbonation-reaction structures, considerable calcite twinning and grain welding immediately below the mirror slip surface. Grains or areas indicating decarbonation reactions show a foam

  8. A Piecewise Affine Hybrid Systems Approach to Fault Tolerant Satellite Formation Control

    DEFF Research Database (Denmark)

    Grunnet, Jacob Deleuran; Larsen, Jesper Abildgaard; Bak, Thomas

    2008-01-01

    In this paper a procedure for modelling satellite formations   including failure dynamics as a piecewise-affine hybrid system is   shown. The formulation enables recently developed methods and tools   for control and analysis of piecewise-affine systems to be applied   leading to synthesis of fault...... tolerant controllers and analysis of   the system behaviour given possible faults.  The method is   illustrated using a simple example involving two satellites trying   to reach a specific formation despite of actuator faults occurring....

  9. Formation of interlayer gap and control of interlayer burr in dry drilling of stacked aluminum alloy plates

    Directory of Open Access Journals (Sweden)

    Tian Wei

    2016-02-01

    Full Text Available In aircraft assembly, interlayer burr formation in dry drilling of stacked metal materials is a common problem. Traditional manual deburring operation seriously affects the assembly quality and assembly efficiency, is time-consuming and costly, and is not conducive to aircraft automatic assembly based on industrial robot. In this paper, the formation of drilling exit burr and the influence of interlayer gap on interlayer burr formation were studied, and the mechanism of interlayer gap formation in drilling stacked aluminum alloy plates was investigated, a simplified mathematical model of interlayer gap based on the theory of plates and shells and finite element method was established. The relationship between interlayer gap and interlayer burr, as well as the effect of feed rate and pressing force on interlayer burr height and interlayer gap was discussed. The result shows that theoretical interlayer gap has a positive correlation with interlayer burr height and preloading pressing force is an effective method to control interlayer burr formation.

  10. Ab initio molecular dynamics simulation of the effects of stacking faults on the radiation response of 3C-SiC.

    Science.gov (United States)

    Jiang, M; Peng, S M; Zhang, H B; Xu, C H; Xiao, H Y; Zhao, F A; Liu, Z J; Zu, X T

    2016-02-16

    In this study, an ab initio molecular dynamics method is employed to investigate how the existence of stacking faults (SFs) influences the response of SiC to low energy irradiation. It reveals that the C and Si atoms around the SFs are generally more difficult to be displaced than those in unfaulted SiC, and the corresponding threshold displacement energies for them are generally larger, indicative of enhanced radiation tolerance caused by the introduction of SFs, which agrees well with the recent experiment. As compared with the unfaulted state, more localized point defects are generated in faulted SiC. Also, the efficiency of damage production for Si recoils is generally higher than that of C recoils. The calculated potential energy increases for defect generation in SiC with intrinsic and extrinsic SFs are found to be higher than those in unfaulted SiC, due to the stronger screen-Coulomb interaction between the PKA and its neighbors. The presented results provide a fundamental insight into the underlying mechanism of displacement events in faulted SiC and will help to advance the understanding of the radiation response of SiC with and without SFs.

  11. Fault detection and isolation of high temperature proton exchange membrane fuel cell stack under the influence of degradation

    Science.gov (United States)

    Jeppesen, Christian; Araya, Samuel Simon; Sahlin, Simon Lennart; Thomas, Sobi; Andreasen, Søren Juhl; Kær, Søren Knudsen

    2017-08-01

    This study proposes a data-drive impedance-based methodology for fault detection and isolation of low and high cathode stoichiometry, high CO concentration in the anode gas, high methanol vapour concentrations in the anode gas and low anode stoichiometry, for high temperature PEM fuel cells. The fault detection and isolation algorithm is based on an artificial neural network classifier, which uses three extracted features as input. Two of the proposed features are based on angles in the impedance spectrum, and are therefore relative to specific points, and shown to be independent of degradation, contrary to other available feature extraction methods in the literature. The experimental data is based on a 35 day experiment, where 2010 unique electrochemical impedance spectroscopy measurements were recorded. The test of the algorithm resulted in a good detectability of the faults, except for high methanol vapour concentration in the anode gas fault, which was found to be difficult to distinguish from a normal operational data. The achieved accuracy for faults related to CO pollution, anode- and cathode stoichiometry is 100% success rate. Overall global accuracy on the test data is 94.6%.

  12. Fault detection and isolation of high temperature proton exchange membrane fuel cell stack under the influence of degradation

    DEFF Research Database (Denmark)

    Jeppesen, Christian; Araya, Samuel Simon; Sahlin, Simon Lennart

    2017-01-01

    This study proposes a data-drive impedance-based methodology for fault detection and isolation of low and high cathode stoichiometry, high CO concentration in the anode gas, high methanol vapour concentrations in the anode gas and low anode stoichiometry, for high temperature PEM fuel cells....... The fault detection and isolation algorithm is based on an artificial neural network classifier, which uses three extracted features as input. Two of the proposed features are based on angles in the impedance spectrum, and are therefore relative to specific points, and shown to be independent of degradation......, contrary to other available feature extraction methods in the literature. The experimental data is based on a 35 day experiment, where 2010 unique electrochemical impedance spectroscopy measurements were recorded. The test of the algorithm resulted in a good detectability of the faults, except for high...

  13. Wurtzite/zinc-blende electronic-band alignment in basal-plane stacking faults in semi-polar GaN

    Science.gov (United States)

    Monavarian, Morteza; Hafiz, Shopan; Izyumskaya, Natalia; Das, Saikat; Özgür, Ümit; Morkoç, Hadis; Avrutin, Vitaliy

    2016-02-01

    Heteroepitaxial semipolar and nonpolar GaN layers often suffer from high densities of extended defects including basal plane stacking faults (BSFs). BSFs which are considered as inclusions of cubic zinc-blende phase in wurtzite matrix act as quantum wells strongly affecting device performance. Band alignment in BSFs has been discussed as type of band alignment at the wurtzite/zinc blende interface governs the response in differential transmission; fast decay after the pulse followed by slow recovery due to spatial splitting of electrons and heavy holes for type- II band alignment in contrast to decay with no recovery in case of type I band alignment. Based on the results, band alignment is demonstrated to be of type II in zinc-blende segments in wurtzite matrix as in BSFs.

  14. I2 basal stacking fault as a degradation mechanism in reverse gate-biased AlGaN/GaN HEMTs

    Science.gov (United States)

    Lang, A. C.; Hart, J. L.; Wen, J. G.; Miller, D. J.; Meyer, D. J.; Taheri, M. L.

    2016-09-01

    Here, we present the observation of a bias-induced, degradation-enhancing defect process in plasma-assisted molecular beam epitaxy grown reverse gate-biased AlGaN/GaN high electron mobility transistors (HEMTs), which is compatible with the current theoretical framework of HEMT degradation. Specifically, we utilize both conventional transmission electron microscopy and aberration-corrected transmission electron microscopy to analyze microstructural changes in not only high strained regions in degraded AlGaN/GaN HEMTs but also the extended gate-drain access region. We find a complex defect structure containing an I2 basal stacking fault and offer a potential mechanism for device degradation based on this defect structure. This work supports the reality of multiple failure mechanisms during device operation and identifies a defect potentially involved with device degradation.

  15. Significance of stacking fault energy on microstructural evolution in Cu and Cu-Al alloys processed by high-pressure torsion

    Science.gov (United States)

    An, X. H.; Lin, Q. Y.; Wu, S. D.; Zhang, Z. F.; Figueiredo, R. B.; Gao, N.; Langdon, T. G.

    2011-09-01

    Disks of pure Cu and several Cu-Al alloys were processed by high-pressure torsion (HPT) at room temperature through different numbers of turns to systematically investigate the influence of the stacking fault energy (SFE) on the evolution of microstructural homogeneity. The results show there is initially an inhomogeneous microhardness distribution but this inhomogneity decreases with increasing numbers of turns and the saturation microhardness increases with increasing Al concentration. Uniform microstructures are more readily achieved in materials with high or low SFE than in materials with medium SFE, because there are different mechanisms governing the microstructural evolution. Specifically, recovery processes are dominant in high or medium SFE materials, whereas twin fragmentation is dominant in materials having low SFE. The limiting minimum grain size (d min) of metals processed by HPT decreases with decreasing SFE and there is additional evidence suggesting that the dependence of d min on the SFE decreases when the severity of the external loading conditions is increased.

  16. Quantitative analysis of CTEM images of small dislocation loops in Al and stacking fault tetrahedra in Cu generated by molecular dynamics simulation

    International Nuclear Information System (INIS)

    Schaeublin, R.; Almazouzi, A.; Dai, Y.; Osetsky, Yu.N.; Victoria, M.

    2000-01-01

    The visibility of conventional transmission electron microscopy (CTEM) images of small crystalline defects generated by molecular dynamics (MD) simulation is investigated. Faulted interstitial dislocation loops in Al smaller than 2 nm in diameter and stacking fault tetrahedra (SFT) in Cu smaller than 4 nm in side are assessed. A recent approach allowing to simulate the CTEM images of computer generated samples described by their atomic positions is applied to obtain bright field and weak beam images. For the dislocation loop-like cluster it appears that the simulated image is comparable to experimental images. The contrast of the g(3.1g) near weak beam image decreases with decreasing size of the cluster but is still 20% of the background intensity for a 2 interstitial cluster. This indicates a visibility at the limit of the experimental background noise. In addition, the cluster image size, which is here always larger than the real size, saturates at about 1 nm when the cluster real size decreases below 1 nm, which corresponds to a cluster of 8 interstitials. For the SFT in Cu the g(6.1g) weak beam image is comparable to experimental images. It appears that the image size is larger than the real size by 20%. A large loss of the contrast features that allows to identify an SFT is observed on the image of the smallest SFT (21 vacancies)

  17. Extensional Fault Evolution and its Flexural Isostatic Response During Iberia-Newfoundland Rifted Margin Formation

    Science.gov (United States)

    Gómez-Romeu, J.; Kusznir, N.; Manatschal, G.; Roberts, A.

    2017-12-01

    During the formation of magma-poor rifted margins, upper lithosphere thinning and stretching is achieved by extensional faulting, however, there is still debate and uncertainty how faults evolve during rifting leading to breakup. Seismic data provides an image of the present-day structural and stratigraphic configuration and thus initial fault geometry is unknown. To understand the geometric evolution of extensional faults at rifted margins it is extremely important to also consider the flexural response of the lithosphere produced by fault displacement resulting in footwall uplift and hangingwall subsidence. We investigate how the flexural isostatic response to extensional faulting controls the structural development of rifted margins. To achieve our aim, we use a kinematic forward model (RIFTER) which incorporates the flexural isostatic response to extensional faulting, crustal thinning, lithosphere thermal loads, sedimentation and erosion. Inputs for RIFTER are derived from seismic reflection interpretation and outputs of RIFTER are the prediction of the structural and stratigraphic consequences of recursive sequential faulting and sedimentation. Using RIFTER we model the simultaneous tectonic development of the Iberia-Newfoundland conjugate rifted margins along the ISE01-SCREECH1 and TGS/LG12-SCREECH2 seismic lines. We quantitatively test and calibrate the model against observed target data restored to breakup time. Two quantitative methods are used to obtain this target data: (i) gravity anomaly inversion which predicts Moho depth and continental lithosphere thinning and (ii) reverse post-rift subsidence modelling to give water and Moho depths at breakup time. We show that extensional faulting occurs on steep ( 60°) normal faults in both proximal and distal parts of rifted margins. Extensional faults together with their flexural isostatic response produce not only sub-horizontal exhumed footwall surfaces (i.e. the rolling hinge model) and highly rotated (60

  18. Quantification of Honeycomb Number-Type Stacking Faults: Application to Na3Ni2BiO6 Cathodes for Na-Ion Batteries.

    Science.gov (United States)

    Liu, Jue; Yin, Liang; Wu, Lijun; Bai, Jianming; Bak, Seong-Min; Yu, Xiqian; Zhu, Yimei; Yang, Xiao-Qing; Khalifah, Peter G

    2016-09-06

    Ordered and disordered samples of honeycomb-lattice Na3Ni2BiO6 were investigated as cathodes for Na-ion batteries, and it was determined that the ordered sample exhibits better electrochemical performance, with a specific capacity of 104 mA h/g delivered at plateaus of 3.5 and 3.2 V (vs Na(+)/Na) with minimal capacity fade during extended cycling. Advanced imaging and diffraction investigations showed that the primary difference between the ordered and disordered samples is the amount of number-type stacking faults associated with the three possible centering choices for each honeycomb layer. A labeling scheme for assigning the number position of honeycomb layers is described, and it is shown that the translational shift vectors between layers provide the simplest method for classifying different repeat patterns. It is demonstrated that the number position of honeycomb layers can be directly determined in high-angle annular dark-field scanning transmission electron microscopy (STEM-HAADF) imaging studies. By the use of fault models derived from STEM studies, it is shown that both the sharp, symmetric subcell peaks and the broad, asymmetric superstructure peaks in powder diffraction patterns can be quantitatively modeled. About 20% of the layers in the ordered monoclinic sample are faulted in a nonrandom manner, while the disordered sample stacking is not fully random but instead contains about 4% monoclinic order. Furthermore, it is shown that the ordered sample has a series of higher-order superstructure peaks associated with 6-, 9-, 12-, and 15-layer periods whose existence is transiently driven by the presence of long-range strain that is an inherent consequence of the synthesis mechanism revealed through the present diffraction and imaging studies. This strain is closely associated with a monoclinic shear that can be directly calculated from cell lattice parameters and is strongly correlated with the degree of ordering in the samples. The present results are

  19. Microstructures imply cataclasis and authigenic mineral formation control geomechanical properties of New Zealand's Alpine Fault

    Science.gov (United States)

    Schuck, B.; Janssen, C.; Schleicher, A. M.; Toy, V. G.; Dresen, G.

    2018-05-01

    The Alpine Fault is capable of generating large (MW > 8) earthquakes and is the main geohazard on South Island, NZ, and late in its 250-291-year seismic cycle. To minimize its hazard potential, it is indispensable to identify and understand the processes influencing the geomechanical behavior and strength-evolution of the fault. High-resolution microstructural, mineralogical and geochemical analyses of the Alpine Fault's core demonstrate wall rock fragmentation, assisted by mineral dissolution, and cementation resulting in the formation of a fine-grained principal slip zone (PSZ). A complex network of anastomosing and mutually cross-cutting calcite veins implies that faulting occurred during episodes of dilation, slip and sealing. Fluid-assisted dilatancy leads to a significant volume increase accommodated by vein formation in the fault core. Undeformed euhedral chlorite crystals and calcite veins that have cut footwall gravels demonstrate that these processes occurred very close to the Earth's surface. Microstructural evidence indicates that cataclastic processes dominate the deformation and we suggest that powder lubrication and grain rolling, particularly influenced by abundant nanoparticles, play a key role in the fault core's velocity-weakening behavior rather than frictional sliding. This is further supported by the absence of smectite, which is reasonable given recently measured geothermal gradients of more than 120 °C km-1 and the impermeable nature of the PSZ, which both limit the growth of this phase and restrict its stability to shallow depths. Our observations demonstrate that high-temperature fluids can influence authigenic mineral formation and thus control the fault's geomechanical behavior and the cyclic evolution of its strength.

  20. Analysis on inflowing of the injecting Water in faulted formation

    Directory of Open Access Journals (Sweden)

    Ji Youjun

    2015-06-01

    Full Text Available As to low permeability reservoir, faults and fractures have a significant impact on effect of water injection and may lead up to the lower efficiency of oil displacement, which will bring about low efficiency of injecting water, and the intended purpose of improving recovery factor by water injection will not be reached. In order to reveal the mechanism for channeling of injecting water, research work is conducted as follows: First of all, based on seepage mechanics, fluid mechanics, rock mass mechanics, and multifield coupling theory, the mathematical model considering fluid–solid coupling of water-flooding development for low permeability reservoir is established, the numerical solution of the coupling model is obtained, and by creating an interface program between the seepage simulation procedure and stress computation program, we set up a feasible method to simulate the process of development of reservoir considering deformation of reservoir stratum; second, some cores are selected to test the stress sensitivity of rock in reservoir, and the relation of permeability and stress is proposed to connect the field parameters of the coupling model; finally, taking the S11 block of Daqing Oilfield, for instance, the seepage field and deformation of reservoir stratum is analyzed, and then the mechanism for leakage of injecting water in this block is given out, and the advice for adjustment of injection–production scheme in the future development stage is provided.

  1. 3D tissue formation by stacking detachable cell sheets formed on nanofiber mesh.

    Science.gov (United States)

    Kim, Min Sung; Lee, Byungjun; Kim, Hong Nam; Bang, Seokyoung; Yang, Hee Seok; Kang, Seong Min; Suh, Kahp-Yang; Park, Suk-Hee; Jeon, Noo Li

    2017-03-23

    We present a novel approach for assembling 3D tissue by layer-by-layer stacking of cell sheets formed on aligned nanofiber mesh. A rigid frame was used to repeatedly collect aligned electrospun PCL (polycaprolactone) nanofiber to form a mesh structure with average distance between fibers 6.4 µm. When human umbilical vein endothelial cells (HUVECs), human foreskin dermal fibroblasts, and skeletal muscle cells (C2C12) were cultured on the nanofiber mesh, they formed confluent monolayers and could be handled as continuous cell sheets with areas 3 × 3 cm 2 or larger. Thicker 3D tissues have been formed by stacking multiple cell sheets collected on frames that can be nested (i.e. Matryoshka dolls) without any special tools. When cultured on the nanofiber mesh, skeletal muscle, C2C12 cells oriented along the direction of the nanofibers and differentiated into uniaxially aligned multinucleated myotube. Myotube cell sheets were stacked (upto 3 layers) in alternating or aligned directions to form thicker tissue with ∼50 µm thickness. Sandwiching HUVEC cell sheets with two dermal fibroblast cell sheets resulted in vascularized 3D tissue. HUVECs formed extensive networks and expressed CD31, a marker of endothelial cells. Cell sheets formed on nanofiber mesh have a number of advantages, including manipulation and stacking of multiple cell sheets for constructing 3D tissue and may find applications in a variety of tissue engineering applications.

  2. Determination of the stacking fault density in highly defective single GaAs nanowires by means of coherent diffraction imaging

    Science.gov (United States)

    Davtyan, Arman; Biermanns, Andreas; Loffeld, Otmar; Pietsch, Ullrich

    2016-06-01

    Coherent x-ray diffraction imaging is used to measure diffraction patterns from individual highly defective nanowires, showing a complex speckle pattern instead of well-defined Bragg peaks. The approach is tested for nanowires of 500 nm diameter and 500 nm height predominately composed by zinc-blende (ZB) and twinned zinc-blende (TZB) phase domains. Phase retrieval is used to reconstruct the measured 2-dimensional intensity patterns recorded from single nanowires with 3.48 nm and 0.98 nm spatial resolution. Whereas the speckle amplitudes and distribution are perfectly reconstructed, no unique solution could be obtained for the phase structure. The number of phase switches is found to be proportional to the number of measured speckles and follows a narrow number distribution. Using data with 0.98 nm spatial resolution the mean number of phase switches is in reasonable agreement with estimates taken from TEM. However, since the resolved phase domain still is 3-4 times larger than a single GaAs bilayer we explain the non-ambiguous phase reconstruction by the fact that depending on starting phase and sequence of subroutines used during the phase retrieval the retrieved phase domain host a different sequence of randomly stacked bilayers. Modelling possible arrangements of bilayer sequences within a phase domain demonstrate that the complex speckle patterns measured can indeed be explained by the random arrangement of the ZB and TZB phase domains.

  3. The formation of graben morphology in the Dead Sea Fault, and its implications

    Science.gov (United States)

    Ben-Avraham, Zvi; Katsman, Regina

    2015-09-01

    The Dead Sea Fault (DSF) is a 1000 km long continental transform. It forms a narrow and elongated valley with uplifted shoulders showing an east-west asymmetry, which is not common in other continental transforms. This topography may have strongly affected the course of human history. Several papers addressed the geomorphology of the DSF, but there is still no consensus with respect to the dominant mechanism of its formation. Our thermomechanical modeling demonstrates that existence of a transform prior to the rifting predefined high strain softening on the faults in the strong upper crust and created a precursor weak zone localizing deformations in the subsequent transtensional period. Together with a slow rate of extension over the Arabian plate, they controlled a narrow asymmetric morphology of the fault. This rift pattern was enhanced by a fast deposition of evaporites from the Sedom Lagoon, which occupied the rift depression for a short time period.

  4. Clay mineral formation and fabric development in the DFDP-1B borehole, central Alpine Fault, New Zealand

    International Nuclear Information System (INIS)

    Schleicher, A.M.; Sutherland, R.; Townend, J.; Toy, V.G.; Van der Pluijm, B.A.

    2015-01-01

    Clay minerals are increasingly recognised as important controls on the state and mechanical behaviour of fault systems in the upper crust. Samples retrieved by shallow drilling from two principal slip zones within the central Alpine Fault, South Island, New Zealand, offer an excellent opportunity to investigate clay formation and fluid-rock interaction in an active fault zone. Two shallow boreholes, DFDP-1A (100.6 m deep) and DFDP-1B (151.4 m) were drilled in Phase 1 of the Deep Fault Drilling Project (DFDP-1) in 2011. We provide a mineralogical and textural analysis of clays in fault gouge extracted from the Alpine Fault. Newly formed smectitic clays are observed solely in the narrow zones of fault gouge in drill core, indicating that localised mineral reactions are restricted to the fault zone. The weak preferred orientation of the clay minerals in the fault gouge indicates minimal strain-driven modification of rock fabrics. While limited in extent, our results support observations from surface outcrops and faults systems elsewhere regarding the key role of clays in fault zones and emphasise the need for future, deeper drilling into the Alpine Fault in order to understand correlative mineralogies and fabrics as a function of higher temperature and pressure conditions. (author).

  5. Signature of dislocations and stacking faults of face-centred cubic nanocrystals in coherent X-ray diffraction patterns: a numerical study.

    Science.gov (United States)

    Dupraz, Maxime; Beutier, Guillaume; Rodney, David; Mordehai, Dan; Verdier, Marc

    2015-06-01

    Crystal defects induce strong distortions in diffraction patterns. A single defect alone can yield strong and fine features that are observed in high-resolution diffraction experiments such as coherent X-ray diffraction. The case of face-centred cubic nanocrystals is studied numerically and the signatures of typical defects close to Bragg positions are identified. Crystals of a few tens of nanometres are modelled with realistic atomic potentials and 'relaxed' after introduction of well defined defects such as pure screw or edge dislocations, or Frank or prismatic loops. Diffraction patterns calculated in the kinematic approximation reveal various signatures of the defects depending on the Miller indices. They are strongly modified by the dissociation of the dislocations. Selection rules on the Miller indices are provided, to observe the maximum effect of given crystal defects in the initial and relaxed configurations. The effect of several physical and geometrical parameters such as stacking fault energy, crystal shape and defect position are discussed. The method is illustrated on a complex structure resulting from the simulated nanoindentation of a gold nanocrystal.

  6. Colour formation on the wings of the butterfly Hypolimnas salmacis by scale stacking.

    Science.gov (United States)

    Siddique, Radwanul Hasan; Vignolini, Silvia; Bartels, Carolin; Wacker, Irene; Hölscher, Hendrik

    2016-11-02

    The butterfly genus Hypolimnas features iridescent blue colouration in some areas of its dorsal wings. Here, we analyse the mechanisms responsible for such colouration on the dorsal wings of Hypolimnas salmacis and experimentally demonstrate that the lower thin lamina in the white cover scales causes the blue iridescence. This outcome contradicts other studies reporting that the radiant blue in Hypolimnas butterflies is caused by complex ridge-lamellar architectures in the upper lamina of the cover scales. Our comprehensive optical study supported by numerical calculation however shows that scale stacking primarily induces the observed colour appearance of Hypolimnas salmacis.

  7. Colour formation on the wings of the butterfly Hypolimnas salmacis by scale stacking

    Science.gov (United States)

    Siddique, Radwanul Hasan; Vignolini, Silvia; Bartels, Carolin; Wacker, Irene; Hölscher, Hendrik

    2016-11-01

    The butterfly genus Hypolimnas features iridescent blue colouration in some areas of its dorsal wings. Here, we analyse the mechanisms responsible for such colouration on the dorsal wings of Hypolimnas salmacis and experimentally demonstrate that the lower thin lamina in the white cover scales causes the blue iridescence. This outcome contradicts other studies reporting that the radiant blue in Hypolimnas butterflies is caused by complex ridge-lamellar architectures in the upper lamina of the cover scales. Our comprehensive optical study supported by numerical calculation however shows that scale stacking primarily induces the observed colour appearance of Hypolimnas salmacis.

  8. Formation of Two-Dimensional Homologous Faults and Oxygen Electrocatalytic Activities in a Perovskite Nickelate.

    Science.gov (United States)

    Bak, Jumi; Bae, Hyung Bin; Kim, Jaehoon; Oh, Jihun; Chung, Sung-Yoon

    2017-05-10

    Atomic-scale direct probing of active sites and subsequent elucidation of the structure-activity relationship are important issues involving oxide-based electrocatalysts to achieve better electrochemical conversion efficiency. By generating Ruddlesden-Popper (RP) two-dimensional homologous faults via simple control of the cation nonstoichiometry in LaNiO 3 thin films, we demonstrate that strong tetragonal distortion of [NiO 6 ] octahedra is induced by more than 20% elongation of Ni-O bonds in the faults. In addition to direct visualization of the elongation by scanning transmission electron microscopy, we identify that the distorted [NiO 6 ] octahedra in the faults show considerably higher electrocatalytic activities than other surface sites during the electrochemical oxygen evolution reaction. This unequivocal evidence of the octahedral distortion and its impact on electrocatalysis in LaNiO 3 suggests that the formation of RP-type faults can provide an efficient way to control the octahedral geometry and thereby remarkably enhance the oxygen catalytic performance of perovskite oxides.

  9. Fault zones as barriers to, or conduits for, fluid flow in argillaceous formations. A microstructural and petrophysical perspective

    International Nuclear Information System (INIS)

    Clennell, M.B.; Knipe, R.J.; Fisher, Q.J.

    1998-01-01

    To improve quantitative predictions of the hydrogeological impact of faults, it is necessary to understand the relationship between the mechanics of rock deformation and the evolution of petrophysical properties. A wide range of fault rocks was analysed, many of the findings and techniques can be applied to lower permeability environments. During fault slip, the microstructure of intact rock is changed by mechanical and chemical processes that together constitute the deformation mechanisms through which the rock volume around and within the fault is strained. Deformation mechanisms all act to reduce porosity and permeability of fault rocks with respect to their precursor lithology. Even thin layers of high permeability may act as important flow pathways, and the potential for fault zones to seal or inter-link high-permeability domains must be taken into account when assessing the suitability of a particular formation for long-term waste disposal. (R.P.)

  10. The influence of stacking fault energy on the mechanical behavior of Cu and Cu-Al alloys: Deformation twinning, work hardening, and dynamic recovery

    Science.gov (United States)

    Rohatgi, Aashish; Vecchio, Kenneth S.; Gray, George T.

    2001-01-01

    The role of stacking fault energy (SFE) in deformation twinning and work hardening was systematically studied in Cu (SFE ˜78 ergs/cm2) and a series of Cu-Al solid-solution alloys (0.2, 2, 4, and 6 wt pct Al with SFE ˜75, 25, 13, and 6 ergs/cm2, respectively). The materials were deformed under quasi-static compression and at strain rates of ˜1000/s in a Split-Hopkinson pressure bar (SHPB). The quasi-static flow curves of annealed 0.2 and 2 wt pct Al alloys were found to be representative of solid-solution strengthening and well described by the Hall-Petch relation. The quasi-static flow curves of annealed 4 and 6 wt pct Al alloys showed additional strengthening at strains greater than 0.10. This additional strengthening was attributed to deformation twins and the presence of twins was confirmed by optical microscopy. The strengthening contribution of deformation twins was incorporated in a modified Hall-Petch equation (using intertwin spacing as the “effective” grain size), and the calculated strength was in agreement with the observed quasi-static flow stresses. While the work-hardening rate of the low SFE Cu-Al alloys was found to be independent of the strain rate, the work-hardening rate of Cu and the high SFE Cu-Al alloys (low Al content) increased with increasing strain rate. The different trends in the dependence of work-hardening rate on strain rate was attributed to the difference in the ease of cross-slip (and, hence, the ease of dynamic recovery) in Cu and Cu-Al alloys.

  11. Confirmation of vanadium complex formation using electrospray mass spectrometry and determination of vanadium speciation by sample stacking capillary electrophoresis

    International Nuclear Information System (INIS)

    Chen Zuliang; Owens, Gary; Naidu, Ravendra

    2007-01-01

    Capillary zone electrophoresis (CZE) with UV detection was used to determine vanadium species. Nitrilotriacetic acid (NTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), ethylene glycol-bis(2-aminoethylether)-tetraacetic acid (EGTA) and 2,6-pyridinedicarboxylic acid (PDCA) were investigated to determine whether these ligands formed stable anionic complexes with vanadium. Of all the ligands studied HEDTA was the most suitable ligand because it gave the largest UV response with reasonable migration time. Electrospray mass spectrometry (ES-MS) was used to confirm the formation of [VO 2 (HEDTA)] 2- and [VO(HEDTA)] 1- in solution. An electrolyte containing 25 mM phosphate, 0.25 mM tetradecyltrimethylammonium bromide (TTAB) at pH 5.5 was optimum for the separation of these anionic vanadium complexes. Sample stacking techniques, including large-volume sample stacking (LVSS) and field-amplified sample injection (FASI), were tested to improve the sensitivity. Best sensitivity was obtained using FASI, with detection limits of 0.001 μM, equivalent to 0.4 μg L -1 , for [VO 2 (HEDTA)] 2- and 0.01 μM, equivalent to 3.4 μg L -1 for [VO(HEDTA)] 1- . The utility of the method for the speciation of V(IV) and V(V) was demonstrated using ground water samples

  12. Confirmation of vanadium complex formation using electrospray mass spectrometry and determination of vanadium speciation by sample stacking capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Chen Zuliang [Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, SA 5095 (Australia)]. E-mail: zuliang.chen@unisa.edu.au; Owens, Gary [Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, SA 5095 (Australia); Naidu, Ravendra [Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, SA 5095 (Australia); CRC for Contamination Assessment and Remediation of Environments, Mawson Lakes Boulevard, Mawson Lakes, SA 5095 (Australia)

    2007-02-28

    Capillary zone electrophoresis (CZE) with UV detection was used to determine vanadium species. Nitrilotriacetic acid (NTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), ethylene glycol-bis(2-aminoethylether)-tetraacetic acid (EGTA) and 2,6-pyridinedicarboxylic acid (PDCA) were investigated to determine whether these ligands formed stable anionic complexes with vanadium. Of all the ligands studied HEDTA was the most suitable ligand because it gave the largest UV response with reasonable migration time. Electrospray mass spectrometry (ES-MS) was used to confirm the formation of [VO{sub 2}(HEDTA)]{sup 2-} and [VO(HEDTA)]{sup 1-} in solution. An electrolyte containing 25 mM phosphate, 0.25 mM tetradecyltrimethylammonium bromide (TTAB) at pH 5.5 was optimum for the separation of these anionic vanadium complexes. Sample stacking techniques, including large-volume sample stacking (LVSS) and field-amplified sample injection (FASI), were tested to improve the sensitivity. Best sensitivity was obtained using FASI, with detection limits of 0.001 {mu}M, equivalent to 0.4 {mu}g L{sup -1}, for [VO{sub 2}(HEDTA)]{sup 2-} and 0.01 {mu}M, equivalent to 3.4 {mu}g L{sup -1} for [VO(HEDTA)]{sup 1-}. The utility of the method for the speciation of V(IV) and V(V) was demonstrated using ground water samples.

  13. Dependence of intermetallic compound formation on the sublayer stacking sequence in Ag–Sn bilayer thin films

    International Nuclear Information System (INIS)

    Rossi, P.J.; Zotov, N.; Bischoff, E.; Mittemeijer, E.J.

    2016-01-01

    Intermetallic compound (IMC) formation in thermally-evaporated Ag–Sn bilayer thin films has been investigated employing especially X-ray diffraction (XRD) and (S)TEM methods. The specific IMCs that are present in the as-deposited state depend sensitively on the stacking sequence of the sublayers. In case of Sn on top of Ag, predominantly Ag 3 Sn is formed, whereas Ag 4 Sn is predominantly present in the as-deposited state for Ag on top of Sn. In the latter case this is accompanied by an extremely fast uptake of a large amount of Sn by the Ag sublayer, leaving behind macroscopic voids in the Sn sublayer. The results are discussed on the basis of the thermodynamics and kinetics of (IMC) product-layer growth in thin films. It is shown that both thermodynamic and kinetic arguments explain the contrasting phenomena observed.

  14. Timing and conditions of clay fault gouge formation on the Naxos detachment (Cyclades, Greece)

    Science.gov (United States)

    Mancktelow, N.; Zwingmann, H.; Mulch, A.

    2016-10-01

    Clay fault gouge from the Naxos detachment (locally up to 1.0-1.5 m thick) is reported and dated for the first time. K-Ar ages on eight clay size fractions from the detachment and a minor fault in the immediate footwall have a narrow range, from 10.3 to 9.0 Ma, with an average of 9.7 ± 0.5 Ma (±1σ). These results are in excellent accord with regional and local age constraints, independently demonstrating the reliability of the method. Hydrogen δD values fall in the range -89 to -95‰, indicating interaction with infiltrating meteoric water during gouge formation, which is consistent with deposition of freshwater sediments in the hanging wall at the same time. Clay mineralogy in the detachment gouge is predominantly mixed layer illite-smectite with subordinate 1 M illite and kaolinite but without higher-temperature 2 M1 illite/mica. Clay fault gouge predominantly formed over a limited time and temperature range, potentially acting as a weak lubricant promoting movement on the Naxos detachment, with correspondingly rapid exhumation and cooling of the underlying footwall.

  15. Use of cycle stacking patterns to define third-order depositional sequences: Middle to Late Cambrian Bonanza King Formation, southern Great basin

    Energy Technology Data Exchange (ETDEWEB)

    Montanez, I.P.; Droser, M.L. (Univ. of California, Riverside (United States))

    1991-03-01

    The Middle to Late Cambrian Bonanza King Formation (CA, NV) is characterized by superimposed scales of cyclicity. Small-scale cycles (0.5 to 10m) occur as shallowing-upward peritidal and subtidal cycles that repeat at high frequencies (10{sup 4} to 10{sup 5}). Systematic changes in stacking patterns of meter-scale cycles define several large-scale (50-250 m) third-order depositional sequences in the Bonanza King Formation. Third-order depositional sequences can be traced within ranges and correlated regionally across the platform. Peritidal cycles in the Bonanza King Formation are both subtidal- and tidal flat-dominated. Tidal flat-dominated cycles consist of muddy bases grading upward into thrombolites or columnar stromatolites all capped by planar stromatolites. Subtidal cycles in the Bonanza King Formation consist of grainstone bases that commonly fine upward and contain stacked hardgrounds. These are overlain by digitate-algal bioherms with grainstone channel fills and/or bioturbated ribbon carbonates with grainstone lenses. Transgressive depositional facies of third-order depositional sequences consist primarily of stacks of subtidal-dominated pertidial cycles and subtidal cycles, whereas regressive depositional facies are dominated by stacks of tidal flat-dominated peritidal cycles and regoliths developed over laminite cycle caps. The use of high frequency cycles in the Bonanza King Formation to delineate regionally developed third-order depositional sequences thus provides a link between cycle stratigraphy and sequence stratigraphy.

  16. Study on the relationship of the fault-block structure feature and sandstone uranium formation in Chaoshui basin north belt

    International Nuclear Information System (INIS)

    Liu Lin

    2006-12-01

    The mineralization conditions for three types of acclivity belt (Baojia Jing A' Lashan Youqi-Tangjia Gou and Taojia Jing CHAOSHUI BASIN NORTH BELT) are analyzed, according to the fault-block acclivity belt, the prospecting goal layer, the interlayer oxidized zone and uranium metallization characteristic and so on. It is considered that the positive fault-block acclivity belt favors containing oxygen and uranium water coming from eclipse source area to go into prospecting goal layer, and advanced the formation of interlayer oxidized zone and sandstone uranium metallization. The antithetic fault-block and the buried fault-block acclivity don't favors containing oxygen and uranium water into prospecting goal layer, and format difficultly interlayer oxidized belt and sandstone uranium metallization. Therefore A'Lashan Youqi-Tangjia Gou part is a uranium mineralization prospect sector. (authors)

  17. Glacially induced faulting along the NW segment of the Sorgenfrei-Tornquist Zone, northern Denmark: Implications for neotectonics and Lateglacial fault-bound basin formation

    Science.gov (United States)

    Brandes, Christian; Steffen, Holger; Sandersen, Peter B. E.; Wu, Patrick; Winsemann, Jutta

    2018-06-01

    The Sorgenfrei-Tornquist Zone (STZ) is the northwestern segment of the Tornquist Zone and extends from Bornholm across the Baltic Sea and northern Denmark into the North Sea. It represents a major lithospheric structure with a significant increase in lithosphere thickness from south to north. A series of meter-scale normal faults and soft-sediment deformation structures (SSDS) are developed in Lateglacial marine and lacustrine sediments, which are exposed along the Lønstrup Klint cliff at the North Sea coast of northern Denmark. These deformed deposits occur in the local Nørre Lyngby basin that forms part of the STZ. Most of the SSDS are postdepositional, implying major tectonic activity between the Allerød and Younger Dryas (∼14 ka to 12 ka). The occurrence of some syn- and metadepositional SSDS point to an onset of tectonic activity at around 14.5 ka. The formation of normal faults is probably the effect of neotectonic movements along the Børglum fault, which represents the northern boundary fault of the STZ in the study area. The narrow and elongated Nørre Lyngby basin can be interpreted as a strike-slip basin that developed due to right-lateral movements at the Børglum fault. As indicated by the SSDS, these movements were most likely accompanied by earthquake(s). Based on the association of SSDS these earthquake(s) had magnitudes of at least Ms ≥ 4.2 or even up to magnitude ∼ 7 as indicated by a fault with 3 m displacement. The outcrop data are supported by a topographic analysis of the terrain that points to a strong impact from the fault activity on the topography, characterized by a highly regular erosional pattern, the evolution of fault-parallel sag ponds and a potential fault scarp with a height of 1-2 m. With finite-element simulations, we test the impact of Late Pleistocene (Weichselian) glaciation-induced Coulomb stress change on the reactivation potential of the Børglum fault. The numerical simulations of deglaciation-related lithospheric

  18. Formation and Characterization of Stacked Nanoscale Layers of Polymers and Silanes on Silicon Surfaces

    Science.gov (United States)

    Ochoa, Rosie; Davis, Brian; Conley, Hiram; Hurd, Katie; Linford, Matthew R.; Davis, Robert C.

    2008-10-01

    Chemical surface patterning at the nanoscale is a critical component of chemically directed assembly of nanoscale devices or sensitive biological molecules onto surfaces. Complete and consistent formation of nanoscale layers of silanes and polymers is a necessary first step for chemical patterning. We explored methods of silanizing silicon substrates for the purpose of functionalizing the surfaces. The chemical functionalization, stability, flatness, and repeatability of the process was characterized by use of ellipsometry, water contact angle, and Atomic Force Microscopy (AFM). We found that forming the highest quality functionalized surfaces was accomplished through use of chemical vapor deposition (CVD). Specifically, surfaces were plasma cleaned and hydrolyzed before the silane was applied. A polymer layer less then 2 nm in thickness was electrostatically bound to the silane layer. The chemical functionalization, stability, flatness, and repeatability of the process was also characterized for the polymer layer using ellipsometry, water contact angle, and AFM.

  19. Silicon passivation and tunneling contact formation by atomic layer deposited Al2O3/ZnO stacks

    NARCIS (Netherlands)

    Garcia-Alonso Garcia, D.; Smit, S.; Bordihn, S.; Kessels, W.M.M.

    2013-01-01

    The passivation of Si by Al2O3/ZnO stacks, which can serve as passivated tunneling contacts or heterojunctions in silicon photovoltaics, was investigated. It was demonstrated that stacks with Al2O3 thicknesses >3 nm lead to lower surface recombination velocities (Seff,max <4 cm s-1) on n- and p-type

  20. Age determination and development of experimental methods for quaternary fault and formation

    International Nuclear Information System (INIS)

    Lee, Kwang Sik; Choi, M. S.; Kim, J. M.

    2004-02-01

    Late cretaceous to early tertiary movement ages were constrained by Rb-Sr and K-Ar dating of fault rocks near the Uljin Nuclear Power Plants. These ages are well reproducible and consistent with geologic context. Tectonic evolution of the northeastern Yeongnam massif, the site of the Uljin Nuclear Power Plants, was investigated on the basis of Rb-Sr, Sm-Nd and Pb isotopic systematics and geochemistry of precambrian basement rocks including the Hosanri Formation, Buncheon granite gneiss, biotite granite gneiss, and Hongjesa granite. The optical ages from the Suryum fault outcrop represent the younger limit of sedimentation timing because they are simply based upon the present-day water content. The lower, Qt 2 terrace at about 18m elevation is correlated with Marine Isotopic Stage (MIS) 5a, although its apparent optical age was consistently reported from 71 to 48 ka. Correlation of shoreline elevations indicates the correspondence of the Qt 3a terrace to MIS 5e, which is supported by stratigraphically concordant optical ages for aeolian sand dunes at the north of the Suryum site. This time scale yields an uplift rate of 0.266 m/ka, requiring the revision of conventional view that the Korean peninsula is tectonically very stable

  1. Age determination and development of experimental methods for quaternary fault and formation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kwang Sik; Choi, M. S.; Kim, J. M. [Korea Basic Science Institute, Daejeon (Korea, Republic of)] (and others)

    2004-02-15

    Late cretaceous to early tertiary movement ages were constrained by Rb-Sr and K-Ar dating of fault rocks near the Uljin Nuclear Power Plants. These ages are well reproducible and consistent with geologic context. Tectonic evolution of the northeastern Yeongnam massif, the site of the Uljin Nuclear Power Plants, was investigated on the basis of Rb-Sr, Sm-Nd and Pb isotopic systematics and geochemistry of precambrian basement rocks including the Hosanri Formation, Buncheon granite gneiss, biotite granite gneiss, and Hongjesa granite. The optical ages from the Suryum fault outcrop represent the younger limit of sedimentation timing because they are simply based upon the present-day water content. The lower, Qt{sub 2} terrace at about 18m elevation is correlated with Marine Isotopic Stage (MIS) 5a, although its apparent optical age was consistently reported from 71 to 48 ka. Correlation of shoreline elevations indicates the correspondence of the Qt{sub 3a} terrace to MIS 5e, which is supported by stratigraphically concordant optical ages for aeolian sand dunes at the north of the Suryum site. This time scale yields an uplift rate of 0.266 m/ka, requiring the revision of conventional view that the Korean peninsula is tectonically very stable.

  2. Algebraic stacks

    Indian Academy of Sciences (India)

    Deligne, Mumford and Artin [DM, Ar2]) and consider algebraic stacks, then we can cons- truct the 'moduli ... the moduli scheme and the moduli stack of vector bundles. First I will give ... 1–31. © Printed in India. 1 ...... Cultura, Spain. References.

  3. Effect of Pressure on Elastic Constants, Generalized Stacking Fault Energy, and Dislocation Properties in Antiperovskite-Type Ni-Rich Nitrides ZnNNi3 and CdNNi3

    KAUST Repository

    Liu, Lili

    2014-07-31

    The elastic properties and generalized stacking fault energy curves of antiperovskite-type Ni-rich nitrides MNNi3 (M = Zn, Cd) under different pressure have been obtained from the first-principles calculations. By using the variational method, the core width and Peierls stresses of (Formula presented.) edge dislocation and screw dislocation in ZnNNi3 and CdNNi3 within the improved Peierls-Nabarro (P-N) model in which the lattice discrete effect is taken into account have been investigated. Whatever the material or the pressure range, the Peierls stress of edge dislocation is smaller than that of screw dislocation. This also demonstrates that the edge dislocation is considered to be the dominant factor in determining the plastic behavior of MNNi3 (M = Zn, Cd) in the pressure range of 0–30 GPa.

  4. Multi-microscopy study of the influence of stacking faults and three-dimensional In distribution on the optical properties of m-plane InGaN quantum wells grown on microwire sidewalls

    Energy Technology Data Exchange (ETDEWEB)

    Mancini, L.; Lefebvre, W.; Houard, J.; Blum, I.; Vurpillot, F.; Rigutti, L., E-mail: lorenzo.rigutti@univ-rouen.fr [Groupe de Physique des Matériaux, UMR CNRS 6634, Normandie University, INSA and University of Rouen, 76800 St Etienne du Rouvray (France); Hernández-Maldonado, D. [Groupe de Physique des Matériaux, UMR CNRS 6634, Normandie University, INSA and University of Rouen, 76800 St Etienne du Rouvray (France); SuperSTEM STFC Daresbury Laboratories, Warrington WA4 4AD (United Kingdom); Eymery, J.; Durand, C. [CEA, CNRS, Université Grenoble Alpes, 38000 Grenoble (France); Tchernycheva, M. [Institut d' Electronique Fondamentale, UMR CNRS 8622, University Paris Saclay, 91405 Orsay (France)

    2016-01-25

    The optical properties of m-plane InGaN/GaN quantum wells grown on microwire sidewalls were investigated carrying out a correlative scanning transmission electron microscopy (STEM), atom probe tomography (APT), and micro-photoluminescence study applied on single nanoscale field-emission tips obtained by a focused ion beam annular milling. Instead of assuming simple rectangular composition profiles, yielding misleading predictions for the optical transition energies, we can thus take into account actual compositional distributions and the presence of stacking faults (SFs). SFs were shown to be responsible for a lowering of the recombination energies of the order of 0.1 eV with respect to those expected for defect-free quantum wells (QWs). Such energy reduction allows establishing a good correspondence between the transition energies observed by optical spectroscopy and those calculated on the basis of the QWs In measured composition and distribution assessed by STEM structural analysis and APT chemical mapping.

  5. A short review of our current understanding of the development of ring faults during collapse caldera formation

    Directory of Open Access Journals (Sweden)

    Adelina eGeyer

    2014-09-01

    Full Text Available The term collapse caldera refers to those volcanic depressions resulting from the sinking of the chamber roof due to the rapid withdrawal of magma during the course of an eruption. During the last three decades, collapse caldera dynamics has been the focus of attention of numerous, theoretical, numerical and experimental studies. Nonetheless, even if there is a tendency to go for a general and comprehensive caldera dynamics model, some key aspects remain unclear, controversial or completely unsolved. This is the case of ring fault nucleation points and propagation and dip direction. Since direct information on calderas’ deeper structure comes mainly from partially eroded calderas or few witnessed collapses, ring faults layout at depth remains still uncertain. This has generated a strong debate over the detailed internal fault and fracture configuration of a caldera collapse and, in more detail, how ring faults initiate and propagate. We offer here a very short description of the main results obtained by those analogue and theoretical/mathematical models applied to the study of collapse caldera formation. We place special attention on those observations related to the nucleation and propagation of the collapse-controlling ring faults. This summary is relevant to understand the current state-of-the-art of this topic and it should be taken under consideration in future works dealing with collapse caldera dynamics.

  6. The Role of Relative Sea Level Changes in Diagenetic Processes and Stacking Pattern of Kangan Formation Sediments in one of the Persian Gulf Fields

    Directory of Open Access Journals (Sweden)

    حسن اشراقی

    2016-01-01

    Full Text Available The Lower to Middle Triassic aged Kangan Formation is one of the most significant carbonate gas reservoirs in Iranian territory. In this study, thin sections data were used to recognize microfacies, sedimentary environments and the interaction between diagenetic processes and facies stacking pattern in a sequence stratigraphic framework. Petrographic studies leaded to recognition of eight microfacies related to three facies belts including tidal flat, lagoon and shoal. Moreover, the observed microfacies patterns indicate a ramp carbonate platform as depositional environment for this carbonate succession. The main diagenetic processes of Kangan Formation include micritization, isopachous and fibrous cements (primary marine diagenesis, dissolution and moldic porosity (meteoric diagenesis, compaction and stylolitization (secondary diagenesis. Based on facies changes, two third-order sequences were specified, each of which could be divided into two systems tracts including transgressive systems tract (TST and highstand systems tract (HST. In addition, sequence boundaries were identified with bedded, massive and nodular anhydrite. These facies, that are indicative of maximum sea level fall, were deposited in hypersaline lagoons. There is a close association between diagenetic processes and relative sea level changes of Kangan Formation, so that diagenetic processes of studied succession have been controlled by sediments stacking patterns during transgression and regression of sea level. During the transgression, the main diagenetic processes in shoal facies are marine cementation and dolomitization in lagoon and tidal flat facies. However, during the sea level fall, these processes include dissolution in shoal facies and dolomitization, anhydrite nodule formation and cementation in lagoon and tidal flat settings.

  7. Fault kinematics and depocenter evolution of oil-bearing, continental successions of the Mina del Carmen Formation (Albian) in the Golfo San Jorge basin, Argentina

    Science.gov (United States)

    Paredes, José Matildo; Plazibat, Silvana; Crovetto, Carolina; Stein, Julián; Cayo, Eric; Schiuma, Ariel

    2013-10-01

    Up to 10% of the liquid hydrocarbons of the Golfo San Jorge basin come from the Mina del Carmen Formation (Albian), an ash-dominated fluvial succession preserved in a variably integrated channel network that evolved coeval to an extensional tectonic event, poorly analyzed up to date. Fault orientation, throw distribution and kinematics of fault populations affecting the Mina del Carmen Formation were investigated using a 3D seismic dataset in the Cerro Dragón field (Eastern Sector of the Golfo San Jorge basin). Thickness maps of the seismic sub-units that integrate the Mina del Carmen Formation, named MEC-A-MEC-C in ascending order, and mapping of fluvial channels performed applying geophysical tools of visualization were integrated to the kinematical analysis of 20 main normal faults of the field. The study provides examples of changes in fault throw patterns with time, associated with faults of different orientations. The "main synrift phase" is characterized by NE-SW striking (mean Az = 49°), basement-involved normal faults that attains its maximum throw on top of the volcanic basement; this set of faults was active during deposition of the Las Heras Group and Pozo D-129 formation. A "second synrift phase" is recognized by E-W striking normal faults (mean Az = 91°) that nucleated and propagated from the Albian Mina del Carmen Formation. Fault activity was localized during deposition of the MEC-A sub-unit, but generalized during deposition of MEC-B sub-unit, producing centripetal and partially isolated depocenters. Upward decreasing in fault activity is inferred by more gradual thickness variation of MEC-C and the overlying Lower Member of Bajo Barreal Formation, evidencing passive infilling of relief associated to fault boundaries, and conformation of wider depocenters with well integrated networks of channels of larger dimensions but random orientation. Lately, the Mina del Carmen Formation was affected by the downward propagation of E-W to ESE-WNW striking

  8. Distributed fault-tolerant time-varying formation control for high-order linear multi-agent systems with actuator failures.

    Science.gov (United States)

    Hua, Yongzhao; Dong, Xiwang; Li, Qingdong; Ren, Zhang

    2017-11-01

    This paper investigates the fault-tolerant time-varying formation control problems for high-order linear multi-agent systems in the presence of actuator failures. Firstly, a fully distributed formation control protocol is presented to compensate for the influences of both bias fault and loss of effectiveness fault. Using the adaptive online updating strategies, no global knowledge about the communication topology is required and the bounds of actuator failures can be unknown. Then an algorithm is proposed to determine the control parameters of the fault-tolerant formation protocol, where the time-varying formation feasible conditions and an approach to expand the feasible formation set are given. Furthermore, the stability of the proposed algorithm is proven based on the Lyapunov-like theory. Finally, two simulation examples are given to demonstrate the effectiveness of the theoretical results. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  9. Rearrangement of van der Waals stacking and formation of a singlet state at T = 90 K in a cluster magnet

    Energy Technology Data Exchange (ETDEWEB)

    Sheckelton, John P.; Plumb, Kemp W.; Trump, Benjamin A.; Broholm, Collin L.; McQueen, Tyrel M.

    2017-01-01

    Insulating Nb3Cl8 is a layered chloride consisting of two-dimensional triangular layers of Seff = 1/2 Nb3Cl13 clusters at room temperature. Magnetic susceptibility measurement show a sharp, hysteretic drop to a temperature independent value below T = 90 K. Specific heat measurements show that the transition is first order, with ΔS ≈ 5 J K-1 mol-1 f.u.-1, and a low temperature T-linear contribution originating from defect spins. Neutron and X-ray diffraction show a lowering of symmetry from trigonal P[3 with combining macron]m1 to monoclinic C2/m symmetry, with a change in layer stacking from –AB–AB– to –AB'–BC'–CA'– and no observed magnetic order. This lowering of symmetry and rearrangement of successive layers evades geometric magnetic frustration to form a singlet ground state. It is the lowest temperature at which a change in stacking sequence is known to occur in a van der Waals solid, occurs in the absence of orbital degeneracies, and suggests that designer 2-D heterostructures may be able to undergo similar phase transitions.

  10. Safety assessment of radioactive waste disposal into geological formations; a preliminary application of fault tree analysis to salt deposits

    International Nuclear Information System (INIS)

    Bertozzi, B.; D'Alessandro, M.; Girardi, F.; Vanossi, M.

    1978-01-01

    The methodology of the fault tree analysis (FTA) has been widely used at the Joint Research Centre of Ispra in nuclear reactor safety studies. The aim of the present work consisted in studying the applicability of this methodology to geological repositories of radioactive wastes, including criteria and approaches for the quantification of probalities of primary events. The present work has just an illustrative purpose. Two ideal cases of saline formations, I.E. a bedded salt and a diapir were chosen as potential disposal sites for radioactive waste. On the basis of arbitrarily assumed hydrogeological features of the salt formations and their surrounding environment, possible phenomena capable of causing the waste to be released from each formation have been discussed and gathered following the logical schemes of the FTA. The assessment of probability values for release events due to natural causes as well as to human actions, over different time periods, up to one million years, has been discussed

  11. Formation of Ruddlesden-Popper Faults and Their Effect on the Magnetic Properties in Pr0.5Sr0.5CoO3 Thin Films.

    Science.gov (United States)

    Jing, Hong-Mei; Cheng, Sheng; Mi, Shao-Bo; Lu, Lu; Liu, Ming; Cheng, Shao-Dong; Jia, Chun-Lin

    2018-01-10

    Epitaxial Pr 0.5 Sr 0.5 CoO 3 thin films have been grown on single-crystalline (La 0.289 Sr 0.712 )(Al 0.633 Ta 0.356 )O 3 (001) substrates by the pulsed laser deposition technique. The magnetic properties and microstructure of these films are investigated. It is found that Ruddlesden-Popper faults (RP faults) can be introduced in the films by changing the laser repetition rate. The segregation of Pr at the RP faults is characterized by atomic-resolution chemical mapping. The formation of the RP faults not only contributes to the epitaxial strain relaxation but also significantly decreases the ferromagnetic long-range order of the films, resulting in lower magnetizations than those of the fault-free films. Our results provide a strategy for tuning the magnetic properties of cobalt-based perovskite films by modifying the microstructure through the film growth process.

  12. Pleistocene Brawley and Ocotillo Formations: Evidence for initial strike-slip deformation along the San Felipe and San Jacinto fault zonez, Southern California

    Science.gov (United States)

    Kirby, S.M.; Janecke, S.U.; Dorsey, R.J.; Housen, B.A.; Langenheim, V.E.; McDougall, K.A.; Steeley, A.N.

    2007-01-01

    We examine the Pleistocene tectonic reorganization of the Pacific-North American plate boundary in the Salton Trough of southern California with an integrated approach that includes basin analysis, magnetostratigraphy, and geologic mapping of upper Pliocene to Pleistocene sedimentary rocks in the San Felipe Hills. These deposits preserve the earliest sedimentary record of movement on the San Felipe and San Jacinto fault zones that replaced and deactivated the late Cenozoic West Salton detachment fault. Sandstone and mudstone of the Brawley Formation accumulated between ???1.1 and ???0.6-0.5 Ma in a delta on the margin of an arid Pleistocene lake, which received sediment from alluvial fans of the Ocotillo Formation to the west-southwest. Our analysis indicates that the Ocotillo and Brawley formations prograded abruptly to the east-northeast across a former mud-dominated perennial lake (Borrego Formation) at ???1.1 Ma in response to initiation of the dextral-oblique San Felipe fault zone. The ???25-km-long San Felipe anticline initiated at about the same time and produced an intrabasinal basement-cored high within the San Felipe-Borrego basin that is recorded by progressive unconformities on its north and south limbs. A disconformity at the base of the Brawley Formation in the eastern San Felipe Hills probably records initiation and early blind slip at the southeast tip of the Clark strand of the San Jacinto fault zone. Our data are consistent with abrupt and nearly synchronous inception of the San Jacinto and San Felipe fault zones southwest of the southern San Andreas fault in the early Pleistocene during a pronounced southwestward broadening of the San Andreas fault zone. The current contractional geometry of the San Jacinto fault zone developed after ???0.5-0.6 Ma during a second, less significant change in structural style. ?? 2007 by The University of Chicago. All rights reserved.

  13. Star Formation Rates in Lyman Break Galaxies: Radio Stacking of LBGs in the COSMOS Field and the Sub-μJy Radio Source Population

    Science.gov (United States)

    Carilli, C. L.; Lee, Nicholas; Capak, P.; Schinnerer, E.; Lee, K.-S.; McCraken, H.; Yun, M. S.; Scoville, N.; Smolčić, V.; Giavalisco, M.; Datta, A.; Taniguchi, Y.; Urry, C. Megan

    2008-12-01

    We present an analysis of the radio properties of large samples of Lyman break galaxies (LBGs) at z ~ 3, 4, and 5 from the COSMOS field. The median stacking analysis yields a statistical detection of the z ~ 3 LBGs (U-band dropouts), with a 1.4 GHz flux density of 0.90 +/- 0.21 μJy. The stacked emission is unresolved, with a size = 3 is smaller than at lower redshifts. Conversely, the radio luminosity for a given star formation rate may be systematically lower at very high redshift. Two possible causes for a suppressed radio luminosity are (1) increased inverse Compton cooling of the relativistic electron population due to scattering off the increasing CMB at high redshift or (2) cosmic-ray diffusion from systematically smaller galaxies. The radio detections of individual sources are consistent with a radio-loud AGN fraction of 0.3%. One source is identified as a very dusty, extreme starburst galaxy (a "submillimeter galaxy"). Based on observations in the COSMOS Legacy Survey including those taken on the HST, Keck, NRAO-VLA, Subaru, KPNO 4 m, CTIO 4 m, and CFHT 3.6 m. The Very Large Array of the National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

  14. Layered Fault Management Architecture

    National Research Council Canada - National Science Library

    Sztipanovits, Janos

    2004-01-01

    ... UAVs or Organic Air Vehicles. The approach of this effort was to analyze fault management requirements of formation flight for fleets of UAVs, and develop a layered fault management architecture which demonstrates significant...

  15. Oxygen Vacancies and Stacking Faults Introduced by Low-Temperature Reduction Improve the Electrochemical Properties of Li2MnO3 Nanobelts as Lithium-Ion Battery Cathodes.

    Science.gov (United States)

    Sun, Ya; Cong, Hengjiang; Zan, Ling; Zhang, Youxiang

    2017-11-08

    Among the Li-rich layered oxides Li 2 MnO 3 has significant theoretical capacity as a cathode material for Li-ion batteries. Pristine Li 2 MnO 3 generally has to be electrochemically activated in the first charge-discharge cycle which causes very low Coulombic efficiency and thus deteriorates its electrochemical properties. In this work, we show that low-temperature reduction can produce a large amount of structural defects such as oxygen vacancies, stacking faults, and orthorhombic LiMnO 2 in Li 2 MnO 3 . The Rietveld refinement analysis shows that, after a reduction reaction with stearic acid at 340 °C for 8 h, pristine Li 2 MnO 3 changes into a Li 2 MnO 3 -LiMnO 2 (0.71/0.29) composite, and the monoclinic Li 2 MnO 3 changes from Li 2.04 Mn 0.96 O 3 in the pristine Li 2 MnO 3 (P-Li 2 MnO 3 ) to Li 2.1 Mn 0.9 O 2.79 in the reduced Li 2 MnO 3 (R-Li 2 MnO 3 ), indicating the production of a large amount of oxygen vacancies in the R-Li 2 MnO 3 . High-resolution transmission electron microscope images show that a high density of stacking faults is also introduced by the low-temperature reduction. When measured as a cathode material for Li-ion batteries, R-Li 2 MnO 3 shows much better electrochemical properties than P-Li 2 MnO 3 . For example, when charged-discharged galvanostatically at 20 mA·g -1 in a voltage window of 2.0-4.8 V, R-Li 2 MnO 3 has Coulombic efficiency of 77.1% in the first charge-discharge cycle, with discharge capacities of 213.8 and 200.5 mA·h·g -1 in the 20th and 30th cycles, respectively. In contrast, under the same charge-discharge conditions, P-Li 2 MnO 3 has Coulombic efficiency of 33.6% in the first charge-discharge cycle, with small discharge capacities of 80.5 and 69.8 mA·h·g -1 in the 20th and 30th cycles, respectively. These materials characterizations, and electrochemical measurements show that low-temperature reduction is one of the effective ways to enhance the performances of Li 2 MnO 3 as a cathode material for Li-ion batteries.

  16. Fault detection and isolation of the attitude control subsystem of spacecraft formation flying using extended Kalman filters

    Science.gov (United States)

    Ghasemi, S.; Khorasani, K.

    2015-10-01

    In this paper, the problem of fault detection and isolation (FDI) of the attitude control subsystem (ACS) of spacecraft formation flying systems is considered. For developing the FDI schemes, an extended Kalman filter (EKF) is utilised which belongs to a class of nonlinear state estimation methods. Three architectures, namely centralised, decentralised, and semi-decentralised, are considered and the corresponding FDI strategies are designed and constructed. Appropriate residual generation techniques and threshold selection criteria are proposed for these architectures. The capabilities of the proposed architectures for accomplishing the FDI tasks are studied through extensive numerical simulations for a team of four satellites in formation flight. Using a confusion matrix evaluation criterion, it is shown that the centralised architecture can achieve the most reliable results relative to the semi-decentralised and decentralised architectures at the expense of availability of a centralised processing module that requires the entire team information set. On the other hand, the semi-decentralised performance is close to the centralised scheme without relying on the availability of the entire team information set. Furthermore, the results confirm that the FDI results in formations with angular velocity measurement sensors achieve higher level of accuracy, true faulty, and precision, along with lower level of false healthy misclassification as compared to the formations that utilise attitude measurement sensors.

  17. Fault diagnosis

    Science.gov (United States)

    Abbott, Kathy

    1990-01-01

    The objective of the research in this area of fault management is to develop and implement a decision aiding concept for diagnosing faults, especially faults which are difficult for pilots to identify, and to develop methods for presenting the diagnosis information to the flight crew in a timely and comprehensible manner. The requirements for the diagnosis concept were identified by interviewing pilots, analyzing actual incident and accident cases, and examining psychology literature on how humans perform diagnosis. The diagnosis decision aiding concept developed based on those requirements takes abnormal sensor readings as input, as identified by a fault monitor. Based on these abnormal sensor readings, the diagnosis concept identifies the cause or source of the fault and all components affected by the fault. This concept was implemented for diagnosis of aircraft propulsion and hydraulic subsystems in a computer program called Draphys (Diagnostic Reasoning About Physical Systems). Draphys is unique in two important ways. First, it uses models of both functional and physical relationships in the subsystems. Using both models enables the diagnostic reasoning to identify the fault propagation as the faulted system continues to operate, and to diagnose physical damage. Draphys also reasons about behavior of the faulted system over time, to eliminate possibilities as more information becomes available, and to update the system status as more components are affected by the fault. The crew interface research is examining display issues associated with presenting diagnosis information to the flight crew. One study examined issues for presenting system status information. One lesson learned from that study was that pilots found fault situations to be more complex if they involved multiple subsystems. Another was pilots could identify the faulted systems more quickly if the system status was presented in pictorial or text format. Another study is currently under way to

  18. Simple model of stacking-fault energies

    DEFF Research Database (Denmark)

    Stokbro, Kurt; Jacobsen, Lærke Wedel

    1993-01-01

    metals, and thereby explain the pronounced differences in energetics in these two classes of metals. The model is discussed in the framework of the effective-medium theory where it is possible to find a functional form for the pair potential and relate the contribution associated with the fourth moment...

  19. Mobilities and dislocation energies of planar faults in an ordered A 3 ...

    Indian Academy of Sciences (India)

    Present work describes the stability of possible planar faults of the A3B (D019) phase with an axial ratio less than the ideal. Mobilities and dislocation energies of various planar faults viz. antiphase boundaries (APBs), superlattice intrinsic stacking faults (SISFs) and complex stacking faults (CSFs) have been computed using ...

  20. Interrelation between rifting, faulting, sedimentation, and mantle serpentinization during continental margin formation

    Science.gov (United States)

    Rupke, L.; Schmid, D. W.; Perez-Gussinye, M.; Hartz, E. H.

    2013-12-01

    We explore the conditions under which mantle serpentinization may take place during continental rifting with 2D thermotectonostratigraphic basin models. The basic concept follows the idea that the entire extending continental crust has to be brittle for crustal scale faulting and mantle serpentinization to occur. The new model tracks the rheological evolution of the continental crust and allows for kinetically controlled mantle serpentinization processes. The isostatic and latent heat effects of the reaction are fully coupled to the structural and thermal solutions. A systematic parameter study shows that a critical stretching factor exists for which complete crustal embrittlement and serpentinization occurs. Sedimentation shifts this critical stretching factor to higher values as both deeper burial and the low thermal conductivity of sediments lead to higher crustal temperatures. Serpentinization reactions are therefore only likely in settings with low sedimentation rates and high stretching factors. In addition, we find that the rate of sediment supply has first order controls on the rheology of the lower crust, which may control the overall margin geometry. We further test these concepts in ideas in a case study for the Norwegian margin. In particular, we evaluate whether the inner lower crustal bodies (LCB) imaged beneath the More and Voring margin could be serpentinized mantle. For this purpose we reconstruct multiple 2D transects through a 3D data set. This reconstruction of the Norwegian margin shows that serpentinization reactions are indeed possible and likely during the Jurassic rift phase. Predicted present-day thicknesses and locations of partially serpentinized mantle rocks fit well to information on LCBs from seismic and gravity data. We conclude that some of the inner LCBs beneath the Norwegian margin may, in fact, be partially serpentinized mantle.

  1. Stack Monitor Operating Experience Review

    International Nuclear Information System (INIS)

    Cadwallader, L.C.; Bruyere, S.A.

    2009-01-01

    Stack monitors are used to sense radioactive particulates and gases in effluent air being vented from rooms of nuclear facilities. These monitors record the levels and types of effluents to the environment. This paper presents the results of a stack monitor operating experience review of the U.S. Department of Energy (DOE) Occurrence Reporting and Processing System (ORPS) database records from the past 18 years. Regulations regarding these monitors are briefly described. Operating experiences reported by the U.S. DOE and in engineering literature sources were reviewed to determine the strengths and weaknesses of these monitors. Electrical faults, radiation instrumentation faults, and human errors are the three leading causes of failures. A representative 'all modes' failure rate is 1E-04/hr. Repair time estimates vary from an average repair time of 17.5 hours (with spare parts on hand) to 160 hours (without spare parts on hand). These data should support the use of stack monitors in any nuclear facility, including the National Ignition Facility and the international ITER project.

  2. Strike-slip tectonics and Quaternary basin formation along the Vienna Basin fault system inferred from Bouguer gravity derivatives

    NARCIS (Netherlands)

    Salcher, B. C.; Meurers, B.; Smit, J.; Decker, K.; HöLzel, M.; Wagreich, M.

    2012-01-01

    The Vienna Basin at the transition between the Alpine and Carpathian belt hosts a number of large Pleistocene sub-basins forming along an active continental scale strike-slip fault (Vienna Basin strike-slip fault). We utilize first-order derivatives from industrial Bouguer gravity data to unravel

  3. The effects of lower crustal strength and preexisting midcrustal shear zones on the formation of continental core complexes and low-angle normal faults

    KAUST Repository

    Wu, Guangliang; Lavier, Luc L.

    2016-01-01

    To investigate the formation of core complexes and low-angle normal faults, we devise thermomechanical simulations on a simplified wedge-like orogenic hinterland that has initial topography, Moho relief, and a preexisting midcrustal shear zone that can accommodate shear at very low angles (<20°). We mainly vary the strength of the lower crust and the frictional strength of the preexisting midcrustal shear zone. We find that the strength of the lower crust and the existence and strength of a preexisting shear zone significantly affect the formation and evolution of core complexes. With increasing lower crustal strength, we recognize varying extensional features with decreasing exhumation rate: these are characterized by bivergent metamorphic massifs, classic Cordilleran metamorphic core complexes, multiple consecutive core complexes (or boudinage structures), and a flexural core complex underlined by a large subsurface low-angle detachment fault with a small convex curvature. Topographic loading and mantle buoyancy forces, together with divergent boundaries, drive a regional lower crustal flow that leads to the exhumation of the lower crust where intensive upper crustal faulting induces strong unloading. The detachment fault is a decoupling zone that accommodates large displacement and accumulates sustained shear strain at very low angle between upper and lower crust. Though the regional stress is largely Andersonian, we find non-Andersonian stress in regions adjacent to the preexisting shear zone and those with high topographic gradient. Our new models provide a view that is generally consistent with geological and geophysical observations on how core complexes form and evolve.

  4. The effects of lower crustal strength and preexisting midcrustal shear zones on the formation of continental core complexes and low-angle normal faults

    KAUST Repository

    Wu, Guangliang

    2016-08-22

    To investigate the formation of core complexes and low-angle normal faults, we devise thermomechanical simulations on a simplified wedge-like orogenic hinterland that has initial topography, Moho relief, and a preexisting midcrustal shear zone that can accommodate shear at very low angles (<20°). We mainly vary the strength of the lower crust and the frictional strength of the preexisting midcrustal shear zone. We find that the strength of the lower crust and the existence and strength of a preexisting shear zone significantly affect the formation and evolution of core complexes. With increasing lower crustal strength, we recognize varying extensional features with decreasing exhumation rate: these are characterized by bivergent metamorphic massifs, classic Cordilleran metamorphic core complexes, multiple consecutive core complexes (or boudinage structures), and a flexural core complex underlined by a large subsurface low-angle detachment fault with a small convex curvature. Topographic loading and mantle buoyancy forces, together with divergent boundaries, drive a regional lower crustal flow that leads to the exhumation of the lower crust where intensive upper crustal faulting induces strong unloading. The detachment fault is a decoupling zone that accommodates large displacement and accumulates sustained shear strain at very low angle between upper and lower crust. Though the regional stress is largely Andersonian, we find non-Andersonian stress in regions adjacent to the preexisting shear zone and those with high topographic gradient. Our new models provide a view that is generally consistent with geological and geophysical observations on how core complexes form and evolve.

  5. Effects of host rock stratigraphy on the formation of ring-faults and the initiation of collapse calderas

    International Nuclear Information System (INIS)

    Kinvig, H S; Geyer, A; Gottsmann, J

    2008-01-01

    Most collapse calderas can be attributed to subsidence of the magma chamber roof along bounding sub-vertical normal faults (ring-faults) after a decompression of the magma chamber, following eruption. Here, we present new numerical models that use a Finite Element Method to investigate the effects of variable crustal stratigraphy (lithology/thickness/order of strata) above a magma chamber, on local stress field distribution and how these in turn compare with existing criteria for ring-fault initiation. Results indicate that the occurrence and relative distribution of mechanically different lithologies may be influential in generating or inhibiting caldera collapse.

  6. Effects of host rock stratigraphy on the formation of ring-faults and the initiation of collapse calderas

    Energy Technology Data Exchange (ETDEWEB)

    Kinvig, H S; Geyer, A; Gottsmann, J [Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queen' s Road, BS8 1RJ, Bristol (United Kingdom)

    2008-10-01

    Most collapse calderas can be attributed to subsidence of the magma chamber roof along bounding sub-vertical normal faults (ring-faults) after a decompression of the magma chamber, following eruption. Here, we present new numerical models that use a Finite Element Method to investigate the effects of variable crustal stratigraphy (lithology/thickness/order of strata) above a magma chamber, on local stress field distribution and how these in turn compare with existing criteria for ring-fault initiation. Results indicate that the occurrence and relative distribution of mechanically different lithologies may be influential in generating or inhibiting caldera collapse.

  7. Himalayan gneiss dome formation in the middle crust and exhumation by normal faulting: New geochronology of Gianbul dome, northwestern India

    Science.gov (United States)

    Horton, Forrest; Lee, Jeffrey; Hacker, Bradley; Bowman-Kamaha'o, Meilani; Cosca, Michael A.

    2015-01-01

    A general lack of consensus about the origin of Himalayan gneiss domes hinders accurate thermomechanical modeling of the orogen. To test whether doming resulted from tectonic contraction (e.g., thrust duplex formation, antiformal bending above a thrust ramp, etc.), channel flow, or via the buoyant rise of anatectic melts, this study investigates the depth and timing of doming processes for Gianbul dome in the western Himalaya. The dome is composed of Greater Himalayan Sequence migmatite, Paleozoic orthogneiss, and metasedimentary rock cut by multiple generations of leucogranite dikes. These rocks record a major penetrative D2 deformational event characterized by a domed foliation and associated NE-SW–trending stretching lineation, and they are flanked by the top-down-to-the-SW (normal-sense) Khanjar shear zone and the top-down-to-the-NE (normal sense) Zanskar shear zone (the western equivalent of the South Tibetan detachment system). Monazite U/Th-Pb geochronology records (1) Paleozoic emplacement of the Kade orthogneiss and associated granite dikes; (2) prograde Barrovian metamorphism from 37 to 33 Ma; (3) doming driven by upper-crustal extension and positive buoyancy of decompression melts between 26 and 22 Ma; and (4) the injection of anatectic melts into the upper levels of the dome—neutralizing the effects of melt buoyancy and potentially adding strength to the host rock—by ca. 22.6 Ma on the southwestern flank and ca. 21 Ma on the northeastern flank. As shown by a northeastward decrease in 40Ar/39Ar muscovite dates from 22.4 to 20.2 Ma, ductile normal-sense displacement within the Zanskar shear zone ended by ca. 22 Ma, after which the Gianbul dome was exhumed as part of a rigid footwall block below the brittle Zanskar normal fault, tilting an estimated 5°–10°SW into its present orientation.

  8. Stack Monitoring System At PUSPATI TRIGA Reactor

    International Nuclear Information System (INIS)

    Zamrul Faizad Omar; Mohd Sabri Minhat; Zareen Khan Abdul Jalil Khan; Ridzuan Abdul Mutalib; Khairulezwan Abdul Manan; Nurfarhana Ayuni Joha; Izhar Abu Hussin

    2014-01-01

    This paper describes the current Stack Monitoring System at PUSPATI TRIGA Reactor (RTP) building. A stack monitoring system is a continuous air monitor placed at the reactor top for monitoring the presence of radioactive gaseous in the effluent air from the RTP building. The system consists of four detectors that provide the reading for background, particulate, Iodine and Noble gas. There is a plan to replace the current system due to frequent fault of the system, thus thorough understanding of the current system is required. Overview of the whole system will be explained in this paper. Some current results would be displayed and moving forward brief plan would be mentioned. (author)

  9. Fuzzy fault diagnosis system of MCFC

    Institute of Scientific and Technical Information of China (English)

    Wang Zhenlei; Qian Feng; Cao Guangyi

    2005-01-01

    A kind of fault diagnosis system of molten carbonate fuel cell (MCFC) stack is proposed in this paper. It is composed of a fuzzy neural network (FNN) and a fault diagnosis element. FNN is able to deal with the information of the expert knowledge and the experiment data efficiently. It also has the ability to approximate any smooth system. FNN is used to identify the fault diagnosis model of MCFC stack. The fuzzy fault decision element can diagnose the state of the MCFC generating system, normal or fault, and can decide the type of the fault based on the outputs of FNN model and the MCFC system. Some simulation experiment results are demonstrated in this paper.

  10. Dynamics of intraoceanic subduction initiation : 1. Oceanic detachment fault inversion and the formation of supra-subduction zone ophiolites

    NARCIS (Netherlands)

    Maffione, Marco; Thieulot, Cedric; van Hinsbergen, Douwe J.J.; Morris, Antony; Plümper, Oliver; Spakman, Wim

    Subduction initiation is a critical link in the plate tectonic cycle. Intraoceanic subduction zones can form along transform faults and fracture zones, but how subduction nucleates parallel to mid-ocean ridges, as in e.g., the Neotethys Ocean during the Jurassic, remains a matter of debate. In

  11. Extensional fault geometry and its flexural isostatic response during the formation of the Iberia - Newfoundland conjugate rifted margins

    Science.gov (United States)

    Gómez-Romeu, Júlia; Kusznir, Nick; Manatschal, Gianreto; Roberts, Alan

    2017-04-01

    Despite magma-poor rifted margins having been extensively studied for the last 20 years, the evolution of extensional fault geometry and the flexural isostatic response to faulting remain still debated topics. We investigate how the flexural isostatic response to faulting controls the structural development of the distal part of rifted margins in the hyper-extended domain and the resulting sedimentary record. In particular we address an important question concerning the geometry and evolution of extensional faults within distal hyper-extended continental crust; are the seismically observed extensional fault blocks in this region allochthons from the upper plate or are they autochthons of the lower plate? In order to achieve our aim we focus on the west Iberian rifted continental margin along the TGS and LG12 seismic profiles. Our strategy is to use a kinematic forward model (RIFTER) to model the tectonic and stratigraphic development of the west Iberia margin along TGS-LG12 and quantitatively test and calibrate the model against breakup paleo-bathymetry, crustal basement thickness and well data. RIFTER incorporates the flexural isostatic response to extensional faulting, crustal thinning, lithosphere thermal loads, sedimentation and erosion. The model predicts the structural and stratigraphic consequences of recursive sequential faulting and sedimentation. The target data used to constrain model predictions consists of two components: (i) gravity anomaly inversion is used to determine Moho depth, crustal basement thickness and continental lithosphere thinning and (ii) reverse post-rift subsidence modelling consisting of flexural backstripping, decompaction and reverse post-rift thermal subsidence modelling is used to give paleo-bathymetry at breakup time. We show that successful modelling of the structural and stratigraphic development of the TGS-LG12 Iberian margin transect also requires the simultaneous modelling of the Newfoundland conjugate margin, which we

  12. Direct detection of near-surface faults by migration of back-scattered surface waves

    KAUST Repository

    Yu, Han; Guo, Bowen; Hanafy, Sherif; Lin, Fan-Chi; Schuster, Gerard T.

    2014-01-01

    We show that diffraction stack migration can be used to estimate the distribution of near-surface faults. The assumption is that near-surface faults generate detectable back-scattered surface waves from impinging surface waves. The processing steps

  13. Fault-tree analysis for probabilistic assessment of radioactive-waste segregation: an application to a plastic clay formation at a specific site

    International Nuclear Information System (INIS)

    D'Alessandro, M.; Bonne, A.

    1982-01-01

    This study concerns a probabilistic safety analysis of potential nuclear-waste repository which may be mined into a Tertiary clay formation underlying the Nuclear Research Centre at Mol (Belgium). The value of the geological barrier has been analyzed in probabilistic terms through the application of the Fault-Tree Analysis (FTA) which can answer two main questions: how can the barrier fail (query) and what is the failure probability (query). FTA has been applied to conceptual radioactive-waste disposal systems. In this paper this methodology has been applied to a specific clay formation, to test the applicability of the procedure to a potential site. With this aim, release probabilities to three different receptors (groundwater, land surface, and atmosphere) were estimated for four different time periods. Because of obvious uncertainties in geology predictive capabilities, a probability band has been obtained. Faulting phenomena are among the main mechanisms having the potential to cause release to groundwater, whereas direct releases to land surface may be linked to various glacial phenomena; on short term, different types of human actions may be important. The overall failure probabilities seem to be sufficiently low to offer a good safety margin. (author)

  14. OpenStack essentials

    CERN Document Server

    Radez, Dan

    2015-01-01

    If you need to get started with OpenStack or want to learn more, then this book is your perfect companion. If you're comfortable with the Linux command line, you'll gain confidence in using OpenStack.

  15. Stack gas treatment

    Science.gov (United States)

    Reeves, Adam A.

    1977-04-12

    Hot stack gases transfer contained heat to a gravity flow of pebbles treated with a catalyst, cooled stacked gases and a sulfuric acid mist is withdrawn from the unit, and heat picked up by the pebbles is transferred to air for combustion or other process. The sulfuric acid (or sulfur, depending on the catalyst) is withdrawn in a recovery unit.

  16. Mastering OpenStack

    CERN Document Server

    Khedher, Omar

    2015-01-01

    This book is intended for system administrators, cloud engineers, and system architects who want to deploy a cloud based on OpenStack in a mid- to large-sized IT infrastructure. If you have a fundamental understanding of cloud computing and OpenStack and want to expand your knowledge, then this book is an excellent checkpoint to move forward.

  17. Stacking with stochastic cooling

    Energy Technology Data Exchange (ETDEWEB)

    Caspers, Fritz E-mail: Fritz.Caspers@cern.ch; Moehl, Dieter

    2004-10-11

    Accumulation of large stacks of antiprotons or ions with the aid of stochastic cooling is more delicate than cooling a constant intensity beam. Basically the difficulty stems from the fact that the optimized gain and the cooling rate are inversely proportional to the number of particles 'seen' by the cooling system. Therefore, to maintain fast stacking, the newly injected batch has to be strongly 'protected' from the Schottky noise of the stack. Vice versa the stack has to be efficiently 'shielded' against the high gain cooling system for the injected beam. In the antiproton accumulators with stacking ratios up to 10{sup 5} the problem is solved by radial separation of the injection and the stack orbits in a region of large dispersion. An array of several tapered cooling systems with a matched gain profile provides a continuous particle flux towards the high-density stack core. Shielding of the different systems from each other is obtained both through the spatial separation and via the revolution frequencies (filters). In the 'old AA', where the antiproton collection and stacking was done in one single ring, the injected beam was further shielded during cooling by means of a movable shutter. The complexity of these systems is very high. For more modest stacking ratios, one might use azimuthal rather than radial separation of stack and injected beam. Schematically half of the circumference would be used to accept and cool new beam and the remainder to house the stack. Fast gating is then required between the high gain cooling of the injected beam and the low gain stack cooling. RF-gymnastics are used to merge the pre-cooled batch with the stack, to re-create free space for the next injection, and to capture the new batch. This scheme is less demanding for the storage ring lattice, but at the expense of some reduction in stacking rate. The talk reviews the 'radial' separation schemes and also gives some

  18. Faults Images

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Through the study of faults and their effects, much can be learned about the size and recurrence intervals of earthquakes. Faults also teach us about crustal...

  19. Shocking Path of Least Resistance Shines Light on Subsurface by Revealing the Paths of Water and the Presence of Faults: Stacked EM Case Studies over Barite Hills Superfund Site in South Carolina

    Science.gov (United States)

    Haggar, K. S.; Nelson, H. R., Jr.; Berent, L. J.

    2017-12-01

    The Barite Hills/Nevada Gold Fields mines are in Late Proterozoic and early Paleozoic rocks of the gold and iron sulfides rich Carolina slate belt. The mines were active from 1989 to1995. EPA and USGS site investigations in 2003 resulted in the declaration of the waste pit areas as a superfund site. The USGS and private consulting firms have evaluated subsurface water flow paths, faults & other groundwater-related features at this superfund site utilizing 2-D conductivity & 3-D electromagnetic (EM) surveys. The USGS employed conductivity to generate instantaneous 2-D profiles to evaluate shallow groundwater patterns. Porous regolith sediments, contaminated water & mine debris have high conductivity whereas bedrock is identified by its characteristic low conductivity readings. Consulting contractors integrated EM technology, magnetic & shallow well data to generate 3-D images of groundwater flow paths at given depths across the superfund site. In so doing several previously undetected faults were identified. Lighting strike data was integrated with the previously evaluated electrical and EM data to determine whether this form of natural-sourced EM data could complement and supplement the more traditional geophysical data described above. Several lightning attributes derived from 3-D lightning volumes were found to correlate to various features identified in the previous geophysical studies. Specifically, the attributes Apparent Resistivity, Apparent Permittivity, Peak Current & Tidal Gravity provided the deepest structural geological framework & provided insights into rock properties & earth tides. Most significantly, Peak Current showed remarkable coincidence with the preferred groundwater flow map identified by one of the contractors utilizing EM technology. This study demonstrates the utility of robust integrated EM technology applications for projects focused on hydrology, geohazards to dams, levees, and structures, as well as mineral and hydrocarbon exploration.

  20. Fault finder

    Science.gov (United States)

    Bunch, Richard H.

    1986-01-01

    A fault finder for locating faults along a high voltage electrical transmission line. Real time monitoring of background noise and improved filtering of input signals is used to identify the occurrence of a fault. A fault is detected at both a master and remote unit spaced along the line. A master clock synchronizes operation of a similar clock at the remote unit. Both units include modulator and demodulator circuits for transmission of clock signals and data. All data is received at the master unit for processing to determine an accurate fault distance calculation.

  1. Fault rocks and veins formation in the crystalline Palaeozoic basement of the N margin of the Littoral Chain (Catalan Coastal Ranges, NE Spain)

    Science.gov (United States)

    Alías, Gemma; Belmonte, Alba; Cantarero, Irene; Inglés, Montserrat; Travé, Anna

    2013-04-01

    The Littoral Chain corresponds to a horst of NE-SW direction formed during the Neogene extension which in the studied area (Collserola-Montnegre massif) is mainly composed by Paleozoic materials. At the northern margin the horst limits with the Vallès basin which is infilled by Miocene detrital materials. In the Forques Hill, two km to the est of Martorell, an excellent outcrop of Ordovician phyllites summarise an spread tectonic evolution from Hercynian to Neogene deformation. This work evaluates the behaviour of phyllites during the Hercynian ductile deformation and later during the fragile Mesozoic and Neogene tectonics. The weakness of these rocks together with the situation very close to the Vallès Fault favour that this area concentrates many deformation structures related to extensional tectonics, such as veins, cataclasites and gouges. Phyllites present a pervasive regional hercynian foliation oriented WNW-ESE and dipping moderately to the NNE; a huge amount of quartz veins, up to 20% of the rock volume, were injected during and immediately after the main foliation development. Two groups of fractures cutting the phyllites can be distinguished in the field according to the fault rock products, the vein infilling, the orientation and the geometry. The first one corresponds to Mesozoic fractures that have a NE-SW trend and dip indistinctly to the NW or SE, in a conjugate system. They are characterized by the formation of a broad zone of 0,2 m up to 1,5 m formed either by cataclasites or en echelon veins that indicate a normal movement. The cataclasites are cohesive greenish rocks, with 50% of clasts of wall rock from mm to dm in size. Neoformed minerals in the matrix are chlorite - albite - barite ± titanite and rutile. Veins are white to pinkish in colour and two types of infill have been identified: albite - chlorite - iron oxides± rutile and dolomite - chlorite. The second group belongs to Neogene fractures which although similar orientation than those

  2. Evidence that proliferation of golgi apparatus depends on both de novo generation from the endoplasmic reticulum and formation from pre-existing stacks during the growth of tobacco BY-2 cells.

    Science.gov (United States)

    Abiodun, Moses Olabiyi; Matsuoka, Ken

    2013-04-01

    In higher plants, the numbers of cytoplasmic-distributed Golgi stacks differ based on function, age and cell type. It has not been clarified how the numbers are controlled, whether all the Golgi apparatus in a cell function equally and whether the increase in Golgi number is a result of the de novo formation from the endoplasmic reticulum (ER) or fission of pre-existing stacks. A tobacco prolyl 4-hydroxylase (NtP4H1.1), which is a cis-Golgi-localizing type II membrane protein, was tagged with a photoconvertible fluorescent protein, mKikGR (monomeric Kikume green red), and expressed in tobacco bright yellow 2 (BY-2) cells. Transformed cells were exposed to purple light to convert the fluorescence from green to red. A time-course analysis after the conversion revealed a progressive increase in green puncta and a decrease in the red puncta. From 3 to 6 h, we observed red, yellow and green fluorescent puncta corresponding to pre-existing Golgi; Golgi containing both pre-existing and newly synthesized protein; and newly synthesized Golgi. Analysis of the number and fluorescence of Golgi at different phases of the cell cycle suggested that an increase in Golgi number with both division and de novo synthesis occurred concomitantly with DNA replication. Investigation with different inhibitors suggested that the formation of new Golgi and the generation of Golgi containing both pre-existing and newly synthesized protein are mediated by different machineries. These results and modeling based on quantified results indicate that the Golgi apparatuses in tobacco BY-2 cells are not uniform and suggest that both de novo synthesis from the ER and Golgi division contribute almost equally to the increase in proliferating cells.

  3. Stacking the Equiangular Spiral

    OpenAIRE

    Agrawal, A.; Azabi, Y. O.; Rahman, B. M.

    2013-01-01

    We present an algorithm that adapts the mature Stack and Draw (SaD) methodology for fabricating the exotic Equiangular Spiral Photonic Crystal Fiber. (ES-PCF) The principle of Steiner chains and circle packing is exploited to obtain a non-hexagonal design using a stacking procedure based on Hexagonal Close Packing. The optical properties of the proposed structure are promising for SuperContinuum Generation. This approach could make accessible not only the equiangular spiral but also other qua...

  4. Reliability analysis and initial requirements for FC systems and stacks

    Science.gov (United States)

    Åström, K.; Fontell, E.; Virtanen, S.

    In the year 2000 Wärtsilä Corporation started an R&D program to develop SOFC systems for CHP applications. The program aims to bring to the market highly efficient, clean and cost competitive fuel cell systems with rated power output in the range of 50-250 kW for distributed generation and marine applications. In the program Wärtsilä focuses on system integration and development. System reliability and availability are key issues determining the competitiveness of the SOFC technology. In Wärtsilä, methods have been implemented for analysing the system in respect to reliability and safety as well as for defining reliability requirements for system components. A fault tree representation is used as the basis for reliability prediction analysis. A dynamic simulation technique has been developed to allow for non-static properties in the fault tree logic modelling. Special emphasis has been placed on reliability analysis of the fuel cell stacks in the system. A method for assessing reliability and critical failure predictability requirements for fuel cell stacks in a system consisting of several stacks has been developed. The method is based on a qualitative model of the stack configuration where each stack can be in a functional, partially failed or critically failed state, each of the states having different failure rates and effects on the system behaviour. The main purpose of the method is to understand the effect of stack reliability, critical failure predictability and operating strategy on the system reliability and availability. An example configuration, consisting of 5 × 5 stacks (series of 5 sets of 5 parallel stacks) is analysed in respect to stack reliability requirements as a function of predictability of critical failures and Weibull shape factor of failure rate distributions.

  5. Detailed facies analyses within the Bluell and Sherwood Members, Mission Canyon Formation, North Dakota, USA - Facies stacking patterns, sequence stratigraphy and porosity relationship, consequences for reservoir distribution

    OpenAIRE

    Sjöstedt, Tony

    2017-01-01

    Detailed core analysis from seven wells with cores cut within the overall carbonate succession that makes up the Bluell and Sherwood Members of the Mission Canyon Formation located in Renville County, North Dakota, resulted in the identification of eleven depositional facies. These facies that reflect a range in depositional conditions from inner to back ramp, that is shallow fair-weather to uppermost intertidal and supratidal conditions. Systematic core analysis using a highly detailed digit...

  6. Towards stacked zone plates

    International Nuclear Information System (INIS)

    Werner, S; Rehbein, S; Guttman, P; Heim, S; Schneider, G

    2009-01-01

    Fresnel zone plates are the key optical elements for soft and hard x-ray microscopy. For short exposure times and minimum radiation load of the specimen the diffraction efficiency of the zone plate objectives has to be maximized. As the efficiency strongly depends on the height of the diffracting zone structures the achievable aspect ratio of the nanostructures determines these limits. To reach aspect ratios ≥ 20:1 for high efficient optics we propose to superimpose zone plates on top of each other. With this multiplication approach the final aspect ratio is only limited by the number of stacked zone plate layers. For the stack process several nanostructuring process steps have to be developed and/or improved. Our results show for the first time two layers of zone plates stacked on top of each other.

  7. Stochastic stacking without filters

    International Nuclear Information System (INIS)

    Johnson, R.P.; Marriner, J.

    1982-12-01

    The rate of accumulation of antiprotons is a critical factor in the design of p anti p colliders. A design of a system to accumulate higher anti p fluxes is presented here which is an alternative to the schemes used at the CERN AA and in the Fermilab Tevatron I design. Contrary to these stacking schemes, which use a system of notch filters to protect the dense core of antiprotons from the high power of the stack tail stochastic cooling, an eddy current shutter is used to protect the core in the region of the stack tail cooling kicker. Without filters one can have larger cooling bandwidths, better mixing for stochastic cooling, and easier operational criteria for the power amplifiers. In the case considered here a flux of 1.4 x 10 8 per sec is achieved with a 4 to 8 GHz bandwidth

  8. Stack filter classifiers

    Energy Technology Data Exchange (ETDEWEB)

    Porter, Reid B [Los Alamos National Laboratory; Hush, Don [Los Alamos National Laboratory

    2009-01-01

    Just as linear models generalize the sample mean and weighted average, weighted order statistic models generalize the sample median and weighted median. This analogy can be continued informally to generalized additive modeels in the case of the mean, and Stack Filters in the case of the median. Both of these model classes have been extensively studied for signal and image processing but it is surprising to find that for pattern classification, their treatment has been significantly one sided. Generalized additive models are now a major tool in pattern classification and many different learning algorithms have been developed to fit model parameters to finite data. However Stack Filters remain largely confined to signal and image processing and learning algorithms for classification are yet to be seen. This paper is a step towards Stack Filter Classifiers and it shows that the approach is interesting from both a theoretical and a practical perspective.

  9. Photoswitchable Intramolecular H-Stacking of Perylenebisimide

    NARCIS (Netherlands)

    Wang, Jiaobing; Kulago, Artem; Browne, Wesley R.; Feringa, Ben L.

    2010-01-01

    Dynamic control over the formation of H- or J-type aggregates of chromophores is of fundamental importance for developing responsive organic optoelectronic materials. In this study, the first example of photoswitching between a nonstacked and an intramolecularly H-stacked arrangement of

  10. Laser pulse stacking method

    Science.gov (United States)

    Moses, E.I.

    1992-12-01

    A laser pulse stacking method is disclosed. A problem with the prior art has been the generation of a series of laser beam pulses where the outer and inner regions of the beams are generated so as to form radially non-synchronous pulses. Such pulses thus have a non-uniform cross-sectional area with respect to the outer and inner edges of the pulses. The present invention provides a solution by combining the temporally non-uniform pulses in a stacking effect to thus provide a more uniform temporal synchronism over the beam diameter. 2 figs.

  11. Passive bookshelf faulting driven by gravitational spreading as the cause of the tiger-stripe-fracture formation and development in the South Polar Terrain of Enceladus

    Science.gov (United States)

    Yin, A.; Pappalardo, R. T.

    2013-12-01

    Detailed photogeologic mapping of the tiger-stripe fractures in the South Polar Terrain (SPT) of Enceladus indicates that these structures are left-slip faults and terminate at hook-shaped fold-thrust zones and/or Y-shaped horsetail splay-fault zones. The semi-square-shaped tectonic domain that hosts the tiger-stripe faults is bounded by right-slip and left-slip faults on the north and south edges and fold-thrust and extensional zones on the western and eastern edges. We explain the above observations by a passive bookshelf-faulting model in which individual tiger-stripe faults are bounded by deformable wall rocks accommodating distributed deformation. Based on topographic data, we suggest that gravitational spreading had caused the SPT to spread unevenly from west to east. This process was accommodated by right-slip and left-slip faulting on the north and south sides and thrusting and extension along the eastern and southern margins of the tiger-stripe tectonic domain. The uneven spreading, expressed by a gradual northward increase in the number of extensional faults and thrusts/folds along the western and eastern margins, was accommodated by distributed right-slip simple shear across the whole tiger-stripe tectonic domain. This mode of deformation in turn resulted in the development of a passive bookshelf-fault system characterized by left-slip faulting on individual tiger-stripe fractures.

  12. Interfacial oxygen and nitrogen induced dipole formation and vacancy passivation for increased effective work functions in TiN/HfO[sub 2] gate stacks

    KAUST Repository

    Hinkle, C. L.

    2010-03-09

    Effective work function (EWF) changes of TiN/HfO2annealed at low temperatures in different ambient environments are correlated with the atomic concentration of oxygen in the TiN near the metal/dielectric interface. EWF increases of 550 meV are achieved with anneals that incorporate oxygen throughout the TiN with [O]=2.8×1021 cm−3 near the TiN/HfO2interface. However, further increasing the oxygen concentration via more aggressive anneals results in a relative decrease of the EWF and increase in electrical thickness. First-principles calculations indicate the exchange of O and N atoms near the TiN/HfO2interface cause the formation of dipoles that increase the EWF.

  13. Learning SaltStack

    CERN Document Server

    Myers, Colton

    2015-01-01

    If you are a system administrator who manages multiple servers, then you know how difficult it is to keep your infrastructure in line. If you've been searching for an easier way, this book is for you. No prior experience with SaltStack is required.

  14. Crustal-Scale Fault Interaction at Rifted Margins and the Formation of Domain-Bounding Breakaway Complexes: Insights From Offshore Norway

    Science.gov (United States)

    Osmundsen, P. T.; Péron-Pinvidic, G.

    2018-03-01

    The large-magnitude faults that control crustal thinning and excision at rifted margins combine into laterally persistent structural boundaries that separate margin domains of contrasting morphology and structure. We term them breakaway complexes. At the Mid-Norwegian margin, we identify five principal breakaway complexes that separate the proximal, necking, distal, and outer margin domains. Downdip and lateral interactions between the faults that constitute breakaway complexes became fundamental to the evolution of the 3-D margin architecture. Different types of fault interaction are observed along and between these faults, but simple models for fault growth will not fully describe their evolution. These structures operate on the crustal scale, cut large thicknesses of heterogeneously layered lithosphere, and facilitate fundamental margin processes such as deformation coupling and exhumation. Variations in large-magnitude fault geometry, erosional footwall incision, and subsequent differential subsidence along the main breakaway complexes likely record the variable efficiency of these processes.

  15. OpenStack cloud security

    CERN Document Server

    Locati, Fabio Alessandro

    2015-01-01

    If you are an OpenStack administrator or developer, or wish to build solutions to protect your OpenStack environment, then this book is for you. Experience of Linux administration and familiarity with different OpenStack components is assumed.

  16. Stacked magnet superconducting bearing

    International Nuclear Information System (INIS)

    Rigney, T.K. II; Saville, M.P.

    1993-01-01

    A superconducting bearing is described, comprising: a plurality of permanent magnets magnetized end-to-end and stacked side-by-side in alternating polarity, such that flux lines flow between ends of adjacent magnets; isolating means, disposed between said adjacent magnets, for reducing flux leakage between opposing sides of said adjacent magnets; and a member made of superconducting material having at least one surface in communication with said flux lines

  17. Iridium Interfacial Stack (IRIS)

    Science.gov (United States)

    Spry, David James (Inventor)

    2015-01-01

    An iridium interfacial stack ("IrIS") and a method for producing the same are provided. The IrIS may include ordered layers of TaSi.sub.2, platinum, iridium, and platinum, and may be placed on top of a titanium layer and a silicon carbide layer. The IrIS may prevent, reduce, or mitigate against diffusion of elements such as oxygen, platinum, and gold through at least some of its layers.

  18. MEAN STACK WEB DEVELOPMENT

    OpenAIRE

    Le Thanh, Nghi

    2017-01-01

    The aim of the thesis is to provide a universal website using JavaScript as the main programming language. It also shows the basic parts anyone need to create a web application. The thesis creates a simple CMS using MEAN stack. MEAN is a collection of JavaScript based technologies used to develop web application. It is an acronym for MongoDB, Express, AngularJS and Node.js. It also allows non-technical users to easily update and manage a website’s content. But the application also lets o...

  19. Die-stacking architecture

    CERN Document Server

    Xie, Yuan

    2015-01-01

    The emerging three-dimensional (3D) chip architectures, with their intrinsic capability of reducing the wire length, promise attractive solutions to reduce the delay of interconnects in future microprocessors. 3D memory stacking enables much higher memory bandwidth for future chip-multiprocessor design, mitigating the ""memory wall"" problem. In addition, heterogenous integration enabled by 3D technology can also result in innovative designs for future microprocessors. This book first provides a brief introduction to this emerging technology, and then presents a variety of approaches to design

  20. Microstructure changes in the low stacking fault energy steel

    International Nuclear Information System (INIS)

    Rodak, K.; Kuc, D.; Niewielski, G.; Hetmanczyk, M.

    1999-01-01

    A Cr-Ni austenitic steel (type 304) was investigated using TEM. It is shown that some structural parameters (dislocations density within the subgrains and the subgrains size) change with temperature and strain rate after hot temperature deformation. The subgrain microstructure was characterized quantitatively for different characteristics. (author)

  1. Asymmetric Flexible Supercapacitor Stack

    Directory of Open Access Journals (Sweden)

    Leela Mohana Reddy A

    2008-01-01

    Full Text Available AbstractElectrical double layer supercapacitor is very significant in the field of electrical energy storage which can be the solution for the current revolution in the electronic devices like mobile phones, camera flashes which needs flexible and miniaturized energy storage device with all non-aqueous components. The multiwalled carbon nanotubes (MWNTs have been synthesized by catalytic chemical vapor deposition technique over hydrogen decrepitated Mischmetal (Mm based AB3alloy hydride. The polymer dispersed MWNTs have been obtained by insitu polymerization and the metal oxide/MWNTs were synthesized by sol-gel method. Morphological characterizations of polymer dispersed MWNTs have been carried out using scanning electron microscopy (SEM, transmission electron microscopy (TEM and HRTEM. An assymetric double supercapacitor stack has been fabricated using polymer/MWNTs and metal oxide/MWNTs coated over flexible carbon fabric as electrodes and nafion®membrane as a solid electrolyte. Electrochemical performance of the supercapacitor stack has been investigated using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy.

  2. Influence of crystal orientation on the formation of femtosecond laser-induced periodic surface structures and lattice defects accumulation

    Energy Technology Data Exchange (ETDEWEB)

    Sedao, Xxx; Garrelie, Florence, E-mail: florence.garrelie@univ-st-etienne.fr; Colombier, Jean-Philippe; Reynaud, Stéphanie; Pigeon, Florent [Université de Lyon, CNRS, UMR5516, Laboratoire Hubert Curien, Université de Saint Etienne, Jean Monnet, F-42023 Saint-Etienne (France); Maurice, Claire; Quey, Romain [Ecole Nationale Supérieure des Mines de Saint-Etienne, CNRS, UMR5307, Laboratoire Georges Friedel, F-42023 Saint-Etienne (France)

    2014-04-28

    The influence of crystal orientation on the formation of femtosecond laser-induced periodic surface structures (LIPSS) has been investigated on a polycrystalline nickel sample. Electron Backscatter Diffraction characterization has been exploited to provide structural information within the laser spot on irradiated samples to determine the dependence of LIPSS formation and lattice defects (stacking faults, twins, dislocations) upon the crystal orientation. Significant differences are observed at low-to-medium number of laser pulses, outstandingly for (111)-oriented surface which favors lattice defects formation rather than LIPSS formation.

  3. Qademah Fault 3D Survey

    KAUST Repository

    Hanafy, Sherif M.

    2014-01-01

    Objective: Collect 3D seismic data at Qademah Fault location to 1. 3D traveltime tomography 2. 3D surface wave migration 3. 3D phase velocity 4. Possible reflection processing Acquisition Date: 26 – 28 September 2014 Acquisition Team: Sherif, Kai, Mrinal, Bowen, Ahmed Acquisition Layout: We used 288 receiver arranged in 12 parallel lines, each line has 24 receiver. Inline offset is 5 m and crossline offset is 10 m. One shot is fired at each receiver location. We use the 40 kgm weight drop as seismic source, with 8 to 15 stacks at each shot location.

  4. Instant BlueStacks

    CERN Document Server

    Judge, Gary

    2013-01-01

    Get to grips with a new technology, understand what it is and what it can do for you, and then get to work with the most important features and tasks. A fast-paced, example-based approach guide for learning BlueStacks.This book is for anyone with a Mac or PC who wants to run Android apps on their computer. Whether you want to play games that are freely available for Android but not your computer, or you want to try apps before you install them on a physical device or use it as a development tool, this book will show you how. No previous experience is needed as this is written in plain English

  5. Fault-related clay authigenesis along the Moab Fault: Implications for calculations of fault rock composition and mechanical and hydrologic fault zone properties

    Science.gov (United States)

    Solum, J.G.; Davatzes, N.C.; Lockner, D.A.

    2010-01-01

    The presence of clays in fault rocks influences both the mechanical and hydrologic properties of clay-bearing faults, and therefore it is critical to understand the origin of clays in fault rocks and their distributions is of great importance for defining fundamental properties of faults in the shallow crust. Field mapping shows that layers of clay gouge and shale smear are common along the Moab Fault, from exposures with throws ranging from 10 to ???1000 m. Elemental analyses of four locations along the Moab Fault show that fault rocks are enriched in clays at R191 and Bartlett Wash, but that this clay enrichment occurred at different times and was associated with different fluids. Fault rocks at Corral and Courthouse Canyons show little difference in elemental composition from adjacent protolith, suggesting that formation of fault rocks at those locations is governed by mechanical processes. Friction tests show that these authigenic clays result in fault zone weakening, and potentially influence the style of failure along the fault (seismogenic vs. aseismic) and potentially influence the amount of fluid loss associated with coseismic dilation. Scanning electron microscopy shows that authigenesis promotes that continuity of slip surfaces, thereby enhancing seal capacity. The occurrence of the authigenesis, and its influence on the sealing properties of faults, highlights the importance of determining the processes that control this phenomenon. ?? 2010 Elsevier Ltd.

  6. A model for the formation of lattice defects at silicon oxide precipitates in silicon

    International Nuclear Information System (INIS)

    Vanhellemont, J.; Gryse, O. de; Clauws, P.

    2003-01-01

    The critical size of silicon oxide precipitates and the formation of lattice defects by the precipitates are discussed. An expression is derived allowing estimation of self-interstitial emission by spherical precipitates as well as strain build-up during precipitate growth. The predictions are compared with published experimental data. A model for stacking fault nucleation at oxide precipitates is developed based on strain and self-interstitial accumulation during the thermal history of the wafer. During a low-temperature treatment high levels of strain develop. During subsequent high-temperature treatment, excess strain energy in the precipitate is released by self-interstitial emission leading to favourable conditions for stacking fault nucleation

  7. Stratigraphic and structural data for the Conasauga Group and the Rome Formation on the Copper Creek fault block near Oak Ridge, Tennessee: preliminary results from test borehole ORNL-JOY No. 2

    International Nuclear Information System (INIS)

    Haase, C.S.; Walls, E.C.; Farmer, C.D.

    1985-06-01

    To resolve long-standing problems with the stratigraphy of the Conasauga Group and the Rome Formation on the Copper Creek fault block near Oak Ridge National Laboratory (ORNL), an 828.5-m-deep test borehole was drilled. Continuous rock core was recovered from the 17.7- to 828.5-m-deep interval; temperature, caliper, neutron, gamma-ray, and acoustic (velocity and televiewer) logs were obtained. The Conasauga Group at the study site is 572.4 m thick and comprises six formations that are - in descending stratigraphic order - Maynardville Limestone (98.8 m), Nolichucky Shale (167.9 m), Maryville Limestone (141.1 m), Rogersville Shale (39.6 m), Rutledge Limestone (30.8 m), and Pumpkin Valley Shale (94.2 m). The formations are lithologically complex, ranging from clastics that consist of shales, mudstones, and siltstones to carbonates that consist of micrites, wackestones, packstones, and conglomerates. The Rome Formation is 188.1 m thick and consists of variably bedded mudstones, siltstones, and sandstones. The Rome Formation thickness represents 88.1 m of relatively undeformed section and 100.0 m of highly deformed, jumbled, and partially repeated section. The bottom of the Rome Formation is marked by a tectonic disconformity that occurs within a 46-m-thick, intensely deformed interval caused by motion along the Copper Creek fault. Results from this study establish the stratigraphy and the lithology of the Conasauga Group and the Rome Formation near ORNL and, for the first time, allow for the unambiguous correlation of cores and geophysical logs from boreholes elsewhere in the ORNL vicinity. 45 refs., 26 figs., 2 tabs

  8. Assessing Elementary Algebra with STACK

    Science.gov (United States)

    Sangwin, Christopher J.

    2007-01-01

    This paper concerns computer aided assessment (CAA) of mathematics in which a computer algebra system (CAS) is used to help assess students' responses to elementary algebra questions. Using a methodology of documentary analysis, we examine what is taught in elementary algebra. The STACK CAA system, http://www.stack.bham.ac.uk/, which uses the CAS…

  9. Spherical Torus Center Stack Design

    International Nuclear Information System (INIS)

    C. Neumeyer; P. Heitzenroeder; C. Kessel; M. Ono; M. Peng; J. Schmidt; R. Woolley; I. Zatz

    2002-01-01

    The low aspect ratio spherical torus (ST) configuration requires that the center stack design be optimized within a limited available space, using materials within their established allowables. This paper presents center stack design methods developed by the National Spherical Torus Experiment (NSTX) Project Team during the initial design of NSTX, and more recently for studies of a possible next-step ST (NSST) device

  10. Modeling fuel cell stack systems

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J H [Los Alamos National Lab., Los Alamos, NM (United States); Lalk, T R [Dept. of Mech. Eng., Texas A and M Univ., College Station, TX (United States)

    1998-06-15

    A technique for modeling fuel cell stacks is presented along with the results from an investigation designed to test the validity of the technique. The technique was specifically designed so that models developed using it can be used to determine the fundamental thermal-physical behavior of a fuel cell stack for any operating and design configuration. Such models would be useful tools for investigating fuel cell power system parameters. The modeling technique can be applied to any type of fuel cell stack for which performance data is available for a laboratory scale single cell. Use of the technique is demonstrated by generating sample results for a model of a Proton Exchange Membrane Fuel Cell (PEMFC) stack consisting of 125 cells each with an active area of 150 cm{sup 2}. A PEMFC stack was also used in the verification investigation. This stack consisted of four cells, each with an active area of 50 cm{sup 2}. Results from the verification investigation indicate that models developed using the technique are capable of accurately predicting fuel cell stack performance. (orig.)

  11. Environmental assessment of phosphogypsum stacks

    International Nuclear Information System (INIS)

    Odat, M.; Al-Attar, L.; Raja, G.; Abdul Ghany, B.

    2009-01-01

    Phosphogypsum is one of the most important by-products of phosphate fertilizer industry. It is kept in large stacks to the west of Homs city. Storing Phosphogypsum as open stacks exposed to various environmental effects, wind and rain, may cause pollution of the surrounding ecosystem (soil, plant, water and air). This study was carried out in order to assess the environmental impact of Phosphogypsum stacks on the surrounding ecosystem. The obtained results show that Phosphogypsum stacks did not increase the concentration of radionuclides, i.e. Radon-222 and Radium-226, the external exposed dose of gamma rays, as well as the concentration of heavy metals in the components of the ecosystem, soil, plant, water and air, as their concentrations did not exceed the permissible limits. However, the concentration of fluorine in the upper layer of soil, located to the east of the Phosphogypsum stacks, increased sufficiently, especially in the dry period of the year. Also, the concentration of fluoride in plants growing up near-by the Phosphogypsum stacks was too high, exceeded the permissible levels. This was reflected in poising plants and animals, feeding on the plants. Consequently, increasing the concentration of fluoride in soil and plants is the main impact of Phosphogypsum stacks on the surrounding ecosystem. Minimising this effect could be achieved by establishing a 50 meter wide protection zone surrounding the Phosphogypsum stacks, which has to be planted with non palatable trees, such as pine and cypress, forming wind barriers. Increasing the concentrations of heavy metals and fluoride in infiltrated water around the stacks was high; hence cautions must be taken to prevent its usage in any application or disposal in adjacent rivers and leaks.(author)

  12. Environmental assessment of phosphogypsum stacks

    International Nuclear Information System (INIS)

    Odat, M.; Al-Attar, L.; Raja, G.; Abdul Ghany, B.

    2008-03-01

    Phosphogypsum is one of the most important by-products of phosphate fertilizer industry. It is kept in large stacks to the west of Homs city. Storing Phosphogypsum as open stacks exposed to various environmental effects, wind and rain, may cause pollution of the surrounding ecosystem (soil, plant, water and air). This study was carried out in order to assess the environmental impact of Phosphogypsum stacks on the surrounding ecosystem. The obtained results show that Phosphogypsum stacks did not increase the concentration of radionuclides, i.e. Radon-222 and Radium-226, the external exposed dose of gamma rays, as well as the concentration of heavy metals in the components of the ecosystem, soil, plant, water and air, as their concentrations did not exceed the permissible limits. However, the concentration of fluorine in the upper layer of soil, located to the east of the Phosphogypsum stacks, increased sufficiently, especially in the dry period of the year. Also, the concentration of fluoride in plants growing up near-by the Phosphogypsum stacks was too high, exceeded the permissible levels. This was reflected in poising plants and animals, feeding on the plants. Consequently, increasing the concentration of fluoride in soil and plants is the main impact of Phosphogypsum stacks on the surrounding ecosystem. Minimising this effect could be achieved by establishing a 50 meter wide protection zone surrounding the Phosphogypsum stacks, which has to be planted with non palatable trees, such as pine and cypress, forming wind barriers. Increasing the concentrations of heavy metals and fluoride in infiltrated water around the stacks was high; hence cautions must be taken to prevent its usage in any application or disposal in adjacent rivers and leaks.(author)

  13. Optimal fault signal estimation

    NARCIS (Netherlands)

    Stoorvogel, Antonie Arij; Niemann, H.H.; Saberi, A.; Sannuti, P.

    2002-01-01

    We consider here both fault identification and fault signal estimation. Regarding fault identification, we seek either exact or almost fault identification. On the other hand, regarding fault signal estimation, we seek either $H_2$ optimal, $H_2$ suboptimal or Hinfinity suboptimal estimation. By

  14. Dips, ramps, and rolls- Evidence for paleotopographic and syn-depositional fault control on the Western Kentucky No. 4 coal bed, tradewater formation (Bolsovian) Illinois Basin

    Science.gov (United States)

    Greb, S.F.; Eble, C.F.; Williams, D.A.; Nelson, W.J.

    2001-01-01

    The Western Kentucky No. 4 coal is a high-volatile B to high-volatile C bituminous coal that has been heavily mined along the southern margin of the Western Kentucky Coal Field. The seam has a reputation for rolling floor elevation. Elongate trends of floor depressions are referred to as "dips" and "rolls" by miners. Some are relatively narrow and straight to slightly curvilinear in plan view, with generally symmetric to slightly asymmetric cross-sections. Others are broader and asymmetric in section, with sharp dips on one limb and gradual, ramp-like dips on the other. Some limbs change laterally from gradual dip, to sharp dip, to offset of the coal. Lateral changes in the rate of floor elevation dip are often associated with changes in coal thickness, and in underground mines, changes in floor elevation are sometimes associated with roof falls and haulage problems. In order to test if coal thickness changes within floor depressions were associated with changes in palynology, petrography and coal quality, the coal was sampled at a surface mine across a broad. ramp-like depression that showed down-dip coal thickening. Increment samples of coal from a thick (150 cm), down-ramp and thinner (127 cm), up-ramp position at one surface mine correlate well between sample sites (a distance of 60 m) except for a single increment. The anomalous increment (31 cm) in the lower-middle part of the thick coal bed contained 20% more Lycospora orbicula spores. The rolling floor elevations noted in the study mines are inferred to have been formed as a result of pre-peat paleotopographic depressions, syn-depositional faulting, fault-controlled pre-peat paleotopography, and from compaction beneath post-depositional channels and slumps. Although the association of thick coal with linear trends and inferred faults has been used in other basins to infer syn-depositional faulting, changes in palynology within increment samples of the seam along a structural ramp in this study provide

  15. Role of stacking disorder in ice nucleation.

    Science.gov (United States)

    Lupi, Laura; Hudait, Arpa; Peters, Baron; Grünwald, Michael; Gotchy Mullen, Ryan; Nguyen, Andrew H; Molinero, Valeria

    2017-11-08

    The freezing of water affects the processes that determine Earth's climate. Therefore, accurate weather and climate forecasts hinge on good predictions of ice nucleation rates. Such rate predictions are based on extrapolations using classical nucleation theory, which assumes that the structure of nanometre-sized ice crystallites corresponds to that of hexagonal ice, the thermodynamically stable form of bulk ice. However, simulations with various water models find that ice nucleated and grown under atmospheric temperatures is at all sizes stacking-disordered, consisting of random sequences of cubic and hexagonal ice layers. This implies that stacking-disordered ice crystallites either are more stable than hexagonal ice crystallites or form because of non-equilibrium dynamical effects. Both scenarios challenge central tenets of classical nucleation theory. Here we use rare-event sampling and free energy calculations with the mW water model to show that the entropy of mixing cubic and hexagonal layers makes stacking-disordered ice the stable phase for crystallites up to a size of at least 100,000 molecules. We find that stacking-disordered critical crystallites at 230 kelvin are about 14 kilojoules per mole of crystallite more stable than hexagonal crystallites, making their ice nucleation rates more than three orders of magnitude higher than predicted by classical nucleation theory. This effect on nucleation rates is temperature dependent, being the most pronounced at the warmest conditions, and should affect the modelling of cloud formation and ice particle numbers, which are very sensitive to the temperature dependence of ice nucleation rates. We conclude that classical nucleation theory needs to be corrected to include the dependence of the crystallization driving force on the size of the ice crystallite when interpreting and extrapolating ice nucleation rates from experimental laboratory conditions to the temperatures that occur in clouds.

  16. RESULTS, RESPONSIBILITY, FAULT AND CONTROL

    Directory of Open Access Journals (Sweden)

    Evgeniy Stoyanov

    2016-09-01

    Full Text Available The paper focuses on the responsibility arising from the registered financial results. The analysis of this responsibility presupposes its evaluation and determination of the role of fault in the formation of negative results. The search for efficiency in this whole process is justified by the understanding of the mechanisms that regulate the behavior of economic actors.

  17. Consolidity: Stack-based systems change pathway theory elaborated

    Directory of Open Access Journals (Sweden)

    Hassen Taher Dorrah

    2014-06-01

    Full Text Available This paper presents an elaborated analysis for investigating the stack-based layering processes during the systems change pathway. The system change pathway is defined as the path resulting from the combinations of all successive changes induced on the system when subjected to varying environments, activities, events, or any excessive internal or external influences and happenings “on and above” its normal stands, situations or set-points during its course of life. The analysis is essentially based on the important overall system paradigm of “Time driven-event driven-parameters change”. Based on this paradigm, it is considered that any affected activity, event or varying environment is intelligently self-recorded inside the system through an incremental consolidity-scaled change in system parameters of the stack-based layering types. Various joint stack-based mathematical and graphical approaches supported by representable case studies are suggested for the identification, extraction, and processing of various stack-based systems changes layering of different classifications and categorizations. Moreover, some selected real life illustrative applications are provided to demonstrate the (infinite stack-based identification and recognition of the change pathway process in the areas of geology, archeology, life sciences, ecology, environmental science, engineering, materials, medicine, biology, sociology, humanities, and other important fields. These case studies and selected applications revealed that there are general similarities of the stack-based layering structures and formations among all the various research fields. Such general similarities clearly demonstrate the global concept of the “fractals-general stacking behavior” of real life systems during their change pathways. Therefore, it is recommended that concentrated efforts should be expedited toward building generic modular stack-based systems or blocks for the mathematical

  18. Calibration of the seismic velocity structure and understanding of the fault formation in the environs of the Orkney M5.5 earthquake, South Africa

    Science.gov (United States)

    Ogasawara, H.; Manzi, M. S.; Durrheim, R. J.; Ogasawara, H.

    2017-12-01

    In August 2014, the largest seismic event (M5.5) to occur in a South African gold mining district took place near Orkney. The M5.5 event and aftershocks were recorded by strainmeters installed at 3 km depth hundreds of meters above the M5.5 fault, 46 in-mine 4.5Hz triaxial geophone stations at depths of 2-3 km within a hypocentral radius of 2-3 km, and 17 surface strong motion stations (South African Seismograph Network; SANSN) within an epicentral radius of 25 km. Aftershocks were distributed on a nearly vertical plane striking NNW-SSE. The upper edge of this fault was hundreds of meters below the deepest level of the mine. ICDP approved a project "Drilling into seismogenic zones of M2.0-5.5 earthquakes in South African gold mines" to elucidate the details of the events (DSeis; Yabe et al. invited talk in S020 in this AGU). On 1 August 2017 drilling was within a few hundreds of meters of intersecting the M5.5 fault zone. To locate the drilling target accurately it is very important to determine the velocity structure between the seismic events and sensors. We do this by using the interval velocities used to migrate 3D-reflection seismic data that was previously acquired by a mining company to image the gold-bearing reef and any fault structures close to the mining horizon. Less attention was given to the velocities below the mining horizon, as accurate imaging of the geological structure was not as important and very little drilling information was available. We used the known depths of prominent reflectors above the mining horizon to derive the interval velocities needed to convert two-way-travel-time to depth. We constrain the velocity below the mining horizon by comparing the DSeis drilling results with the 3D seismic cube. The geometric data is crucial for the kinematic modeling that Ogasawara et al. (S018 in this AGU) advocates. The efforts will result in a better understanding of the main rupture and aftershocks.

  19. Supposed capable fault analysis as supporting data for Nuclear Power Plant in Bojonegara, Banten province

    International Nuclear Information System (INIS)

    Purnomo Raharjo; June Mellawati; Yarianto SBS

    2016-01-01

    Fault location and the regions radius 150 km of a fault line or fault zones was rejected area or at the Nuclear Power Plant site. The objective of this study was to identify the existence of surface fault or supposed capable fault at 150 km from the interest site. Methodology covers interpretation of fault structure, seismic analysis reflection on land and sea, seismotectonic analysis, and determining areas which are free from the surface fault. The regional study area, which has the radius of 150 kilometers from the interest, includes the province of Banten, Jakarta, West Java, And South Sumatra (some part of Lampung). The results of Landsat image interpretation showed fault structure pattern northeast-southwest which represent Cimandiri fault, northwest-southeast represent Citandui fault, Baribis fault, Tangkuban Perahu fault. The northeast - southwest fault is estimated as left lateral faults, and northwest - southeast fault trending is estimated as right lateral faults. Based on the seismic data on land, the fault that rise through to Cisubuh formation are classified as supposed capable fault. Data of seismic stratigraphy sequence analysis at the sea correlated with a unit of the age deposition in the Pleistocene, where divided into Qt (Tertiary boundary and Early Pleistocene), Q1 (Early Pleistocene boundary and Middle Pleistocene) and Q2 (Midle Pleistocene boundary and Late Pleistocene), supposed capable fault pierce early to late Pleistocene sequence. The results of the seismotectonic analysis showed that there are capable fault which is estimated as supposed capable fault. (author)

  20. Information Based Fault Diagnosis

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2008-01-01

    Fault detection and isolation, (FDI) of parametric faults in dynamic systems will be considered in this paper. An active fault diagnosis (AFD) approach is applied. The fault diagnosis will be investigated with respect to different information levels from the external inputs to the systems. These ...

  1. Glassy carbon based supercapacitor stacks

    Energy Technology Data Exchange (ETDEWEB)

    Baertsch, M; Braun, A; Koetz, R; Haas, O [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    Considerable effort is being made to develop electrochemical double layer capacitors (EDLC) that store relatively large quantities of electrical energy and possess at the same time a high power density. Our previous work has shown that glassy carbon is suitable as a material for capacitor electrodes concerning low resistance and high capacity requirements. We present the development of bipolar electrochemical glassy carbon capacitor stacks of up to 3 V. Bipolar stacks are an efficient way to meet the high voltage and high power density requirements for traction applications. Impedance and cyclic voltammogram measurements are reported here and show the frequency response of a 1, 2, and 3 V stack. (author) 3 figs., 1 ref..

  2. Time-predictable Stack Caching

    DEFF Research Database (Denmark)

    Abbaspourseyedi, Sahar

    completely. Thus, in systems with hard deadlines the worst-case execution time (WCET) of the real-time software running on them needs to be bounded. Modern architectures use features such as pipelining and caches for improving the average performance. These features, however, make the WCET analysis more...... addresses, provides an opportunity to predict and tighten the WCET of accesses to data in caches. In this thesis, we introduce the time-predictable stack cache design and implementation within a time-predictable processor. We introduce several optimizations to our design for tightening the WCET while...... keeping the timepredictability of the design intact. Moreover, we provide a solution for reducing the cost of context switching in a system using the stack cache. In design of these caches, we use custom hardware and compiler support for delivering time-predictable stack data accesses. Furthermore...

  3. Stack semantics of type theory

    DEFF Research Database (Denmark)

    Coquand, Thierry; Mannaa, Bassel; Ruch, Fabian

    2017-01-01

    We give a model of dependent type theory with one univalent universe and propositional truncation interpreting a type as a stack, generalizing the groupoid model of type theory. As an application, we show that countable choice cannot be proved in dependent type theory with one univalent universe...

  4. Multilayer Piezoelectric Stack Actuator Characterization

    Science.gov (United States)

    Sherrit, Stewart; Jones, Christopher M.; Aldrich, Jack B.; Blodget, Chad; Bao, Xioaqi; Badescu, Mircea; Bar-Cohen, Yoseph

    2008-01-01

    Future NASA missions are increasingly seeking to use actuators for precision positioning to accuracies of the order of fractions of a nanometer. For this purpose, multilayer piezoelectric stacks are being considered as actuators for driving these precision mechanisms. In this study, sets of commercial PZT stacks were tested in various AC and DC conditions at both nominal and extreme temperatures and voltages. AC signal testing included impedance, capacitance and dielectric loss factor of each actuator as a function of the small-signal driving sinusoidal frequency, and the ambient temperature. DC signal testing includes leakage current and displacement as a function of the applied DC voltage. The applied DC voltage was increased to over eight times the manufacturers' specifications to investigate the correlation between leakage current and breakdown voltage. Resonance characterization as a function of temperature was done over a temperature range of -180C to +200C which generally exceeded the manufacturers' specifications. In order to study the lifetime performance of these stacks, five actuators from one manufacturer were driven by a 60volt, 2 kHz sine-wave for ten billion cycles. The tests were performed using a Lab-View controlled automated data acquisition system that monitored the waveform of the stack electrical current and voltage. The measurements included the displacement, impedance, capacitance and leakage current and the analysis of the experimental results will be presented.

  5. V-stack piezoelectric actuator

    Science.gov (United States)

    Ardelean, Emil V.; Clark, Robert L.

    2001-07-01

    Aeroelastic control of wings by means of a distributed, trailing-edge control surface is of interest with regards to maneuvers, gust alleviation, and flutter suppression. The use of high energy density, piezoelectric materials as motors provides an appealing solution to this problem. A comparative analysis of the state of the art actuators is currently being conducted. A new piezoelectric actuator design is presented. This actuator meets the requirements for trailing edge flap actuation in both stroke and force. It is compact, simple, sturdy, and leverages stroke geometrically with minimum force penalties while displaying linearity over a wide range of stroke. The V-Stack Piezoelectric Actuator, consists of a base, a lever, two piezoelectric stacks, and a pre-tensioning element. The work is performed alternately by the two stacks, placed on both sides of the lever. Pre-tensioning can be readily applied using a torque wrench, obviating the need for elastic elements and this is for the benefit of the stiffness of the actuator. The characteristics of the actuator are easily modified by changing the base or the stacks. A prototype was constructed and tested experimentally to validate the theoretical model.

  6. Open stack thermal battery tests

    Energy Technology Data Exchange (ETDEWEB)

    Long, Kevin N. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Roberts, Christine C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Grillet, Anne M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Headley, Alexander J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Fenton, Kyle [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wong, Dennis [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ingersoll, David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-04-17

    We present selected results from a series of Open Stack thermal battery tests performed in FY14 and FY15 and discuss our findings. These tests were meant to provide validation data for the comprehensive thermal battery simulation tools currently under development in Sierra/Aria under known conditions compared with as-manufactured batteries. We are able to satisfy this original objective in the present study for some test conditions. Measurements from each test include: nominal stack pressure (axial stress) vs. time in the cold state and during battery ignition, battery voltage vs. time against a prescribed current draw with periodic pulses, and images transverse to the battery axis from which cell displacements are computed. Six battery configurations were evaluated: 3, 5, and 10 cell stacks sandwiched between 4 layers of the materials used for axial thermal insulation, either Fiberfrax Board or MinK. In addition to the results from 3, 5, and 10 cell stacks with either in-line Fiberfrax Board or MinK insulation, a series of cell-free “control” tests were performed that show the inherent settling and stress relaxation based on the interaction between the insulation and heat pellets alone.

  7. Adding large EM stack support

    KAUST Repository

    Holst, Glendon

    2016-12-01

    Serial section electron microscopy (SSEM) image stacks generated using high throughput microscopy techniques are an integral tool for investigating brain connectivity and cell morphology. FIB or 3View scanning electron microscopes easily generate gigabytes of data. In order to produce analyzable 3D dataset from the imaged volumes, efficient and reliable image segmentation is crucial. Classical manual approaches to segmentation are time consuming and labour intensive. Semiautomatic seeded watershed segmentation algorithms, such as those implemented by ilastik image processing software, are a very powerful alternative, substantially speeding up segmentation times. We have used ilastik effectively for small EM stacks – on a laptop, no less; however, ilastik was unable to carve the large EM stacks we needed to segment because its memory requirements grew too large – even for the biggest workstations we had available. For this reason, we refactored the carving module of ilastik to scale it up to large EM stacks on large workstations, and tested its efficiency. We modified the carving module, building on existing blockwise processing functionality to process data in manageable chunks that can fit within RAM (main memory). We review this refactoring work, highlighting the software architecture, design choices, modifications, and issues encountered.

  8. Summary: beyond fault trees to fault graphs

    International Nuclear Information System (INIS)

    Alesso, H.P.; Prassinos, P.; Smith, C.F.

    1984-09-01

    Fault Graphs are the natural evolutionary step over a traditional fault-tree model. A Fault Graph is a failure-oriented directed graph with logic connectives that allows cycles. We intentionally construct the Fault Graph to trace the piping and instrumentation drawing (P and ID) of the system, but with logical AND and OR conditions added. Then we evaluate the Fault Graph with computer codes based on graph-theoretic methods. Fault Graph computer codes are based on graph concepts, such as path set (a set of nodes traveled on a path from one node to another) and reachability (the complete set of all possible paths between any two nodes). These codes are used to find the cut-sets (any minimal set of component failures that will fail the system) and to evaluate the system reliability

  9. The cenozoic strike-slip faults and TTHE regional crust stability of Beishan area

    International Nuclear Information System (INIS)

    Guo Zhaojie; Zhang Zhicheng; Zhang Chen; Liu Chang; Zhang Yu; Wang Ju; Chen Weiming

    2008-01-01

    The remote sensing images and geological features of Beishan area indicate that the Altyn Tagh fault, Sanweishan-Shuangta fault, Daquan fault and Hongliuhe fault are distributed in Beishan area from south to north. The faults are all left-lateral strike-slip faults with trending of NE40-50°, displaying similar distribution pattern. The secondary branch faults are developed at the end of each main strike-slip fault with nearly east to west trending form dendritic oblique crossings at the angle of 30-50°. Because of the left-lateral slip of the branch faults, the granites or the blocks exposed within the branch faults rotate clockwisely, forming 'Domino' structures. So the structural style of Beishan area consists of the Altyn Tagh fault, Sanweishan-Shuangta fault, Daquan fault, Hongliuhe fault and their branch faults and rotational structures between different faults. Sedimentary analysis on the fault valleys in the study area and ESR chronological test of fault clay exhibit that the Sanweishan-Shuangta fault form in the late Pliocene (N2), while the Daquan fault displays formation age of l.5-1.2 Ma, and the activity age of the relevant branch faults is Late Pleistocene (400 ka). The ages become younger from the Altyn Tagh fault to the Daquan fault and strike-slip faults display NW trending extension, further revealing the lateral growth process of the strike-slip boundary at the northern margin during the Cenozoic uplift of Tibetan Plateau. The displacement amounts on several secondary faults caused by the activities of the faults are slight due to the above-mentioned structural distribution characteristics of Beishan area, which means that this area is the most stable active area with few seismic activities. We propose the main granitic bodies in Beishan area could be favorable preselected locations for China's high level radioactive waste repository. (authors)

  10. Fault tree handbook

    International Nuclear Information System (INIS)

    Haasl, D.F.; Roberts, N.H.; Vesely, W.E.; Goldberg, F.F.

    1981-01-01

    This handbook describes a methodology for reliability analysis of complex systems such as those which comprise the engineered safety features of nuclear power generating stations. After an initial overview of the available system analysis approaches, the handbook focuses on a description of the deductive method known as fault tree analysis. The following aspects of fault tree analysis are covered: basic concepts for fault tree analysis; basic elements of a fault tree; fault tree construction; probability, statistics, and Boolean algebra for the fault tree analyst; qualitative and quantitative fault tree evaluation techniques; and computer codes for fault tree evaluation. Also discussed are several example problems illustrating the basic concepts of fault tree construction and evaluation

  11. Fault geometry and earthquake mechanics

    Directory of Open Access Journals (Sweden)

    D. J. Andrews

    1994-06-01

    Full Text Available Earthquake mechanics may be determined by the geometry of a fault system. Slip on a fractal branching fault surface can explain: 1 regeneration of stress irregularities in an earthquake; 2 the concentration of stress drop in an earthquake into asperities; 3 starting and stopping of earthquake slip at fault junctions, and 4 self-similar scaling of earthquakes. Slip at fault junctions provides a natural realization of barrier and asperity models without appealing to variations of fault strength. Fault systems are observed to have a branching fractal structure, and slip may occur at many fault junctions in an earthquake. Consider the mechanics of slip at one fault junction. In order to avoid a stress singularity of order 1/r, an intersection of faults must be a triple junction and the Burgers vectors on the three fault segments at the junction must sum to zero. In other words, to lowest order the deformation consists of rigid block displacement, which ensures that the local stress due to the dislocations is zero. The elastic dislocation solution, however, ignores the fact that the configuration of the blocks changes at the scale of the displacement. A volume change occurs at the junction; either a void opens or intense local deformation is required to avoid material overlap. The volume change is proportional to the product of the slip increment and the total slip since the formation of the junction. Energy absorbed at the junction, equal to confining pressure times the volume change, is not large enongh to prevent slip at a new junction. The ratio of energy absorbed at a new junction to elastic energy released in an earthquake is no larger than P/µ where P is confining pressure and µ is the shear modulus. At a depth of 10 km this dimensionless ratio has th value P/µ= 0.01. As slip accumulates at a fault junction in a number of earthquakes, the fault segments are displaced such that they no longer meet at a single point. For this reason the

  12. Deep Fault Recognizer: An Integrated Model to Denoise and Extract Features for Fault Diagnosis in Rotating Machinery

    Directory of Open Access Journals (Sweden)

    Xiaojie Guo

    2016-12-01

    Full Text Available Fault diagnosis in rotating machinery is significant to avoid serious accidents; thus, an accurate and timely diagnosis method is necessary. With the breakthrough in deep learning algorithm, some intelligent methods, such as deep belief network (DBN and deep convolution neural network (DCNN, have been developed with satisfactory performances to conduct machinery fault diagnosis. However, only a few of these methods consider properly dealing with noises that exist in practical situations and the denoising methods are in need of extensive professional experiences. Accordingly, rethinking the fault diagnosis method based on deep architectures is essential. Hence, this study proposes an automatic denoising and feature extraction method that inherently considers spatial and temporal correlations. In this study, an integrated deep fault recognizer model based on the stacked denoising autoencoder (SDAE is applied to both denoise random noises in the raw signals and represent fault features in fault pattern diagnosis for both bearing rolling fault and gearbox fault, and trained in a greedy layer-wise fashion. Finally, the experimental validation demonstrates that the proposed method has better diagnosis accuracy than DBN, particularly in the existing situation of noises with superiority of approximately 7% in fault diagnosis accuracy.

  13. Eigenvector of gravity gradient tensor for estimating fault dips considering fault type

    Science.gov (United States)

    Kusumoto, Shigekazu

    2017-12-01

    The dips of boundaries in faults and caldera walls play an important role in understanding their formation mechanisms. The fault dip is a particularly important parameter in numerical simulations for hazard map creation as the fault dip affects estimations of the area of disaster occurrence. In this study, I introduce a technique for estimating the fault dip using the eigenvector of the observed or calculated gravity gradient tensor on a profile and investigating its properties through numerical simulations. From numerical simulations, it was found that the maximum eigenvector of the tensor points to the high-density causative body, and the dip of the maximum eigenvector closely follows the dip of the normal fault. It was also found that the minimum eigenvector of the tensor points to the low-density causative body and that the dip of the minimum eigenvector closely follows the dip of the reverse fault. It was shown that the eigenvector of the gravity gradient tensor for estimating fault dips is determined by fault type. As an application of this technique, I estimated the dip of the Kurehayama Fault located in Toyama, Japan, and obtained a result that corresponded to conventional fault dip estimations by geology and geomorphology. Because the gravity gradient tensor is required for this analysis, I present a technique that estimates the gravity gradient tensor from the gravity anomaly on a profile.

  14. Electrically Conductive and Protective Coating for Planar SOFC Stacks

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jung-Pyung; Stevenson, Jeffry W.

    2017-12-04

    Ferritic stainless steels are preferred interconnect materials for intermediate temperature SOFCs because of their resistance to oxidation, high formability and low cost. However, their protective oxide layer produces Cr-containing volatile species at SOFC operating temperatures and conditions, which can cause cathode poisoning. Electrically conducting spinel coatings have been developed to prevent cathode poisoning and to maintain an electrically conductive pathway through SOFC stacks. However, this coating is not compatible with the formation of stable, hermetic seals between the interconnect frame component and the ceramic cell. Thus, a new aluminizing process has been developed by PNNL to enable durable sealing, prevent Cr evaporation, and maintain electrical insulation between stack repeat units. Hence, two different types of coating need to have stable operation of SOFC stacks. This paper will focus on the electrically conductive coating process. Moreover, an advanced coating process, compatible with a non-electrically conductive coating will be

  15. Late Quaternary Normal Faulting and Hanging Wall Basin Evolution of the Southwestern Rift Margin from Gravity and Geology, B.C.S., MX and Exploring the Influence of Text-Figure Format on Introductory Geology Learning

    Science.gov (United States)

    Busch, Melanie M. D.

    2011-01-01

    An array of north-striking, left-stepping, active normal faults is situated along the southwestern margin of the Gulf of California. This normal fault system is the marginal fault system of the oblique-divergent plate boundary within the Gulf of California. To better understand the role of upper-crustal processes during development of an obliquely…

  16. Geophysical Imaging of Fault Structures Over the Qadimah Fault, Saudi Arabia

    KAUST Repository

    AlTawash, Feras

    2011-06-01

    The purpose of this study is to use geophysical imaging methods to identify the conjectured location of the ‘Qadimah fault’ near the ‘King Abdullah Economic City’, Saudi Arabia. Towards this goal, 2-D resistivity and seismic surveys were conducted at two different locations, site 1 and site 2, along the proposed trace of the ‘Qadimah fault’. Three processing techniques were used to validate the fault (i) 2-D travel time tomography, (ii) resistivity imaging, and (iii) reflection trim stacking. The refraction traveltime tomograms at site 1 and site 2 both show low-velocity zones (LVZ’s) next to the conjectured fault trace. These LVZ’s are interpreted as colluvial wedges that are often observed on the downthrown side of normal faults. The resistivity tomograms are consistent with this interpretation in that there is a significant change in resistivity values along the conjectured fault trace. Processing the reflection data did not clearly reveal the existence of a fault, and is partly due to the sub-optimal design of the reflection experiment. Overall, the results of this study strongly, but not definitively, suggest the existence of the Qadimah fault in the ‘King Abdullah Economic City’ region of Saudi Arabia.

  17. Fault Tolerant Feedback Control

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, H.

    2001-01-01

    An architecture for fault tolerant feedback controllers based on the Youla parameterization is suggested. It is shown that the Youla parameterization will give a residual vector directly in connection with the fault diagnosis part of the fault tolerant feedback controller. It turns out...... that there is a separation be-tween the feedback controller and the fault tolerant part. The closed loop feedback properties are handled by the nominal feedback controller and the fault tolerant part is handled by the design of the Youla parameter. The design of the fault tolerant part will not affect the design...... of the nominal feedback con-troller....

  18. Vertical melting of a stack of membranes

    Science.gov (United States)

    Borelli, M. E. S.; Kleinert, H.; Schakel, A. M. J.

    2001-02-01

    A stack of tensionless membranes with nonlinear curvature energy and vertical harmonic interaction is studied. At low temperatures, the system forms a lamellar phase. At a critical temperature, the stack disorders vertically in a melting-like transition.

  19. Editorial: Spatial arrangement of faults and opening-mode fractures

    Science.gov (United States)

    Laubach, Stephen E.; Lamarche, Juliette; Gauthier, Bertand D. M.; Dunne, William M.

    2018-03-01

    This issue of the Journal of Structural Geology titled Spatial arrangement of faults and opening-mode fractures explores a fundamental characteristic of fault and fracture arrays. The pattern of fault and opening-mode fracture positions in space defines structural heterogeneity and anisotropy in a rock volume, governs how faults and fractures affect fluid flow, and impacts our understanding of the initiation, propagation and interactions during the formation of fracture patterns. This special issue highlights recent progress with respect to characterizing and understanding the spatial arrangements of fault and fracture patterns, providing examples over a wide range of scales and structural settings.

  20. Helping Students Design HyperCard Stacks.

    Science.gov (United States)

    Dunham, Ken

    1995-01-01

    Discusses how to teach students to design HyperCard stacks. Highlights include introducing HyperCard, developing storyboards, introducing design concepts and scripts, presenting stacks, evaluating storyboards, and continuing projects. A sidebar presents a HyperCard stack evaluation form. (AEF)

  1. Design of fault simulator

    Energy Technology Data Exchange (ETDEWEB)

    Gabbar, Hossam A. [Faculty of Energy Systems and Nuclear Science, University of Ontario Institute of Technology (UOIT), Ontario, L1H 7K4 (Canada)], E-mail: hossam.gabbar@uoit.ca; Sayed, Hanaa E.; Osunleke, Ajiboye S. [Okayama University, Graduate School of Natural Science and Technology, Division of Industrial Innovation Sciences Department of Intelligent Systems Engineering, Okayama 700-8530 (Japan); Masanobu, Hara [AspenTech Japan Co., Ltd., Kojimachi Crystal City 10F, Kojimachi, Chiyoda-ku, Tokyo 102-0083 (Japan)

    2009-08-15

    Fault simulator is proposed to understand and evaluate all possible fault propagation scenarios, which is an essential part of safety design and operation design and support of chemical/production processes. Process models are constructed and integrated with fault models, which are formulated in qualitative manner using fault semantic networks (FSN). Trend analysis techniques are used to map real time and simulation quantitative data into qualitative fault models for better decision support and tuning of FSN. The design of the proposed fault simulator is described and applied on experimental plant (G-Plant) to diagnose several fault scenarios. The proposed fault simulator will enable industrial plants to specify and validate safety requirements as part of safety system design as well as to support recovery and shutdown operation and disaster management.

  2. Iowa Bedrock Faults

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — This fault coverage locates and identifies all currently known/interpreted fault zones in Iowa, that demonstrate offset of geologic units in exposure or subsurface...

  3. Fault detection and isolation in systems with parametric faults

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, Hans Henrik

    1999-01-01

    The problem of fault detection and isolation of parametric faults is considered in this paper. A fault detection problem based on parametric faults are associated with internal parameter variations in the dynamical system. A fault detection and isolation method for parametric faults is formulated...

  4. PRECISION COSMOGRAPHY WITH STACKED VOIDS

    International Nuclear Information System (INIS)

    Lavaux, Guilhem; Wandelt, Benjamin D.

    2012-01-01

    We present a purely geometrical method for probing the expansion history of the universe from the observation of the shape of stacked voids in spectroscopic redshift surveys. Our method is an Alcock-Paczyński (AP) test based on the average sphericity of voids posited on the local isotropy of the universe. It works by comparing the temporal extent of cosmic voids along the line of sight with their angular, spatial extent. We describe the algorithm that we use to detect and stack voids in redshift shells on the light cone and test it on mock light cones produced from N-body simulations. We establish a robust statistical model for estimating the average stretching of voids in redshift space and quantify the contamination by peculiar velocities. Finally, assuming that the void statistics that we derive from N-body simulations is preserved when considering galaxy surveys, we assess the capability of this approach to constrain dark energy parameters. We report this assessment in terms of the figure of merit (FoM) of the dark energy task force and in particular of the proposed Euclid mission which is particularly suited for this technique since it is a spectroscopic survey. The FoM due to stacked voids from the Euclid wide survey may double that of all other dark energy probes derived from Euclid data alone (combined with Planck priors). In particular, voids seem to outperform baryon acoustic oscillations by an order of magnitude. This result is consistent with simple estimates based on mode counting. The AP test based on stacked voids may be a significant addition to the portfolio of major dark energy probes and its potentialities must be studied in detail.

  5. Docker on OpenStack

    OpenAIRE

    Agarwal, Nitin; Moreira, Belmiro

    2014-01-01

    Project Specification CERN is establishing a large scale private cloud based on OpenStack as part of the expansion of the computing infrastructure for storing the data coming out of the Large Hadron Collider (LHC) experiments. As the data coming out of the detectors is increasing continuously that needs to be stored in the data center, we need more physical resources (more money) and since Virtual machines takes lot of CPU and memory overhead and minutes for creating the images, booting u...

  6. Automatic Fault Characterization via Abnormality-Enhanced Classification

    Energy Technology Data Exchange (ETDEWEB)

    Bronevetsky, G; Laguna, I; de Supinski, B R

    2010-12-20

    Enterprise and high-performance computing systems are growing extremely large and complex, employing hundreds to hundreds of thousands of processors and software/hardware stacks built by many people across many organizations. As the growing scale of these machines increases the frequency of faults, system complexity makes these faults difficult to detect and to diagnose. Current system management techniques, which focus primarily on efficient data access and query mechanisms, require system administrators to examine the behavior of various system services manually. Growing system complexity is making this manual process unmanageable: administrators require more effective management tools that can detect faults and help to identify their root causes. System administrators need timely notification when a fault is manifested that includes the type of fault, the time period in which it occurred and the processor on which it originated. Statistical modeling approaches can accurately characterize system behavior. However, the complex effects of system faults make these tools difficult to apply effectively. This paper investigates the application of classification and clustering algorithms to fault detection and characterization. We show experimentally that naively applying these methods achieves poor accuracy. Further, we design novel techniques that combine classification algorithms with information on the abnormality of application behavior to improve detection and characterization accuracy. Our experiments demonstrate that these techniques can detect and characterize faults with 65% accuracy, compared to just 5% accuracy for naive approaches.

  7. Fault tolerant computing systems

    International Nuclear Information System (INIS)

    Randell, B.

    1981-01-01

    Fault tolerance involves the provision of strategies for error detection damage assessment, fault treatment and error recovery. A survey is given of the different sorts of strategies used in highly reliable computing systems, together with an outline of recent research on the problems of providing fault tolerance in parallel and distributed computing systems. (orig.)

  8. Fault zone hydrogeology

    Science.gov (United States)

    Bense, V. F.; Gleeson, T.; Loveless, S. E.; Bour, O.; Scibek, J.

    2013-12-01

    Deformation along faults in the shallow crust (research effort of structural geologists and hydrogeologists. However, we find that these disciplines often use different methods with little interaction between them. In this review, we document the current multi-disciplinary understanding of fault zone hydrogeology. We discuss surface- and subsurface observations from diverse rock types from unlithified and lithified clastic sediments through to carbonate, crystalline, and volcanic rocks. For each rock type, we evaluate geological deformation mechanisms, hydrogeologic observations and conceptual models of fault zone hydrogeology. Outcrop observations indicate that fault zones commonly have a permeability structure suggesting they should act as complex conduit-barrier systems in which along-fault flow is encouraged and across-fault flow is impeded. Hydrogeological observations of fault zones reported in the literature show a broad qualitative agreement with outcrop-based conceptual models of fault zone hydrogeology. Nevertheless, the specific impact of a particular fault permeability structure on fault zone hydrogeology can only be assessed when the hydrogeological context of the fault zone is considered and not from outcrop observations alone. To gain a more integrated, comprehensive understanding of fault zone hydrogeology, we foresee numerous synergistic opportunities and challenges for the discipline of structural geology and hydrogeology to co-evolve and address remaining challenges by co-locating study areas, sharing approaches and fusing data, developing conceptual models from hydrogeologic data, numerical modeling, and training interdisciplinary scientists.

  9. Performance based fault diagnosis

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik

    2002-01-01

    Different aspects of fault detection and fault isolation in closed-loop systems are considered. It is shown that using the standard setup known from feedback control, it is possible to formulate fault diagnosis problems based on a performance index in this general standard setup. It is also shown...

  10. Aftershocks illuminate the 2011 Mineral, Virginia, earthquake causative fault zone and nearby active faults

    Science.gov (United States)

    Horton, J. Wright; Shah, Anjana K.; McNamara, Daniel E.; Snyder, Stephen L.; Carter, Aina M

    2015-01-01

    Deployment of temporary seismic stations after the 2011 Mineral, Virginia (USA), earthquake produced a well-recorded aftershock sequence. The majority of aftershocks are in a tabular cluster that delineates the previously unknown Quail fault zone. Quail fault zone aftershocks range from ~3 to 8 km in depth and are in a 1-km-thick zone striking ~036° and dipping ~50°SE, consistent with a 028°, 50°SE main-shock nodal plane having mostly reverse slip. This cluster extends ~10 km along strike. The Quail fault zone projects to the surface in gneiss of the Ordovician Chopawamsic Formation just southeast of the Ordovician–Silurian Ellisville Granodiorite pluton tail. The following three clusters of shallow (<3 km) aftershocks illuminate other faults. (1) An elongate cluster of early aftershocks, ~10 km east of the Quail fault zone, extends 8 km from Fredericks Hall, strikes ~035°–039°, and appears to be roughly vertical. The Fredericks Hall fault may be a strand or splay of the older Lakeside fault zone, which to the south spans a width of several kilometers. (2) A cluster of later aftershocks ~3 km northeast of Cuckoo delineates a fault near the eastern contact of the Ordovician Quantico Formation. (3) An elongate cluster of late aftershocks ~1 km northwest of the Quail fault zone aftershock cluster delineates the northwest fault (described herein), which is temporally distinct, dips more steeply, and has a more northeastward strike. Some aftershock-illuminated faults coincide with preexisting units or structures evident from radiometric anomalies, suggesting tectonic inheritance or reactivation.

  11. Fault-related-folding structure and reflection seismic sections. Construction of earth model using balanced cross section; Danso ga kaizaisuru shukyoku kozo no keitai to jishin tansa danmen. 1. Balanced cross section wo mochiita chika model no kochiku

    Energy Technology Data Exchange (ETDEWEB)

    Matsuoka, T; Tamagawa, T [Japan Petroleum Exploration Corp., Tokyo (Japan); Tsukui, R [Japan National Oil Corp., Tokyo (Japan). Technology Research Center

    1997-05-27

    Pre-stacking depth migration treatment is studied for the estimation of the fold configuration from seismic survey cross sections. The estimation of a velocity structure is necessary for the execution of such treatment, and the utilization of structural-geological knowledge is required for its interpretation. The concept of balanced cross section in relation to the fault-bend fold constructs a stratum structure model under conditions that the deformation during fold and fault formation is a planar strain, that there is no change in volume due to deformation, and that a fold is a parallel fold. In addition to the above geometric and kinetic approach, there is another fold formation process simulation model using a Newtonian fluid for study from the viewpoint of dynamics. This simulation stands on the presumption that the boundary contains a ramp that had been in presence before fold formation and that an incompressible viscous matter is mounted on the top surface. The viscous matter flows and deforms for the formation of an anticline on the ramp. Such enables the reproduction of a fault-bend fold formation process, and helpful discussion may be furthered on the dynamic aspect of this simulation. 5 refs., 4 figs.

  12. Lightweight Stacks of Direct Methanol Fuel Cells

    Science.gov (United States)

    Narayanan, Sekharipuram; Valdez, Thomas

    2004-01-01

    An improved design concept for direct methanol fuel cells makes it possible to construct fuel-cell stacks that can weigh as little as one-third as much as do conventional bipolar fuel-cell stacks of equal power. The structural-support components of the improved cells and stacks can be made of relatively inexpensive plastics. Moreover, in comparison with conventional bipolar fuel-cell stacks, the improved fuel-cell stacks can be assembled, disassembled, and diagnosed for malfunctions more easily. These improvements are expected to bring portable direct methanol fuel cells and stacks closer to commercialization. In a conventional bipolar fuel-cell stack, the cells are interspersed with bipolar plates (also called biplates), which are structural components that serve to interconnect the cells and distribute the reactants (methanol and air). The cells and biplates are sandwiched between metal end plates. Usually, the stack is held together under pressure by tie rods that clamp the end plates. The bipolar stack configuration offers the advantage of very low internal electrical resistance. However, when the power output of a stack is only a few watts, the very low internal resistance of a bipolar stack is not absolutely necessary for keeping the internal power loss acceptably low.

  13. Solid Oxide Fuel Cell Stack Diagnostics

    DEFF Research Database (Denmark)

    Mosbæk, Rasmus Rode; Barfod, Rasmus Gottrup

    As SOFC technology is moving closer to a commercial break through, methods to measure the “state-of-health” of operating stacks are becoming of increasing interest. This requires application of advanced methods for detailed electrical and electrochemical characterization during operation....... An operating stack is subject to compositional gradients in the gaseous reactant streams, and temperature gradients across each cell and across the stack, which complicates detailed analysis. Several experimental stacks from Topsoe Fuel Cell A/S were characterized using Electrochemical Impedance Spectroscopy...... in the hydrogen fuel gas supplied to the stack. EIS was used to examine the long-term behavior and monitor the evolution of the impedance of each of the repeating units and the whole stack. The observed impedance was analyzed in detail for one of the repeating units and the whole stack and the losses reported...

  14. Empirical studies of flexural strength for dry-stack Interlocking masonry

    African Journals Online (AJOL)

    Tests were carried out to establish the flexural strength of dry-stack masonry under vertical and horizontal bending. Two formats of wallettes were tested. Format 1 made of specimens constructed span normal to bed joints, which were tested under vertical bending and Format 2 specimens constructed span parallel to bed ...

  15. Evidence for submarine landslides and continental slope erosion related to fault reactivation during the last glaciation offshore eastern Canada

    Science.gov (United States)

    Saint-Ange, F.; Campbell, C.; MacKillop, K.; Mosher, D. C.; Piper, D. J.; Roger, J.

    2012-12-01

    Many studies have proposed that reactivation of dormant faults during deglaciation is a source of neotectonic activity in glaciated regions, but few have demonstrated the relationship to submarine landslides. In this study, seabed morphology and shallow geology of the outer continental margin adjacent to the Charlie Gibbs Fracture Zone off Newfoundland, Canada was investigated for evidence of this relationship. The glacial history and morphology of the margin suggest that the entire continental shelf in the area, coincident with major continental crustal lineaments, was ice-covered during the Last glacial cycle, and transverse troughs delineate the paleo-icestream drainage patterns. A recent investigation of Notre Dame Trough revealed the existence of large sediment failures on the shelf. The current study investigates complex seafloor erosion and widespread mass transport deposition (MTD) on the continental slope seaward of Notre Dame Trough, using recently-acquired high resolution seismic reflection data and piston cores. The new data reveal that a trough mouth fan (TMF) is present on the slope seaward of Notre Dame Trough. The Notre Dame TMF is characterized by a succession of stacked debris flows, but does not show a lobate shape in plan view like other classic TMFs. Instead, the Notre Dame TMF has abruptly-truncated margins suggesting post-depositional failure and erosion of the fan deposits. Seismic reflection data show that the locations of the failures along the TMF margin are coincident with a set of shallow faults; however the current dataset does not image the deeper portion of the faults. On the upper slope immediately south of the TMF, a narrow and deeply incised canyon is located along-trend with the Notre Dame Trough. The location of this canyon appears to be controlled by a fault. Downslope from this canyon, along the southern margin of the TMF, a 25 km wide, flat-floored, U-shaped valley was eroded into a succession of stacked MTD-filled channels

  16. Qademah Fault Passive Data

    KAUST Repository

    Hanafy, Sherif M.

    2014-01-01

    OBJECTIVE: In this field trip we collect passive data to 1. Convert passive to surface waves 2. Locate Qademah fault using surface wave migration INTRODUCTION: In this field trip we collected passive data for several days. This data will be used to find the surface waves using interferometry and then compared to active-source seismic data collected at the same location. A total of 288 receivers are used. A 3D layout with 5 m inline intervals and 10 m cross line intervals is used, where we used 12 lines with 24 receivers at each line. You will need to download the file (rec_times.mat), it contains important information about 1. Field record no 2. Record day 3. Record month 4. Record hour 5. Record minute 6. Record second 7. Record length P.S. 1. All files are converted from original format (SEG-2) to matlab format P.S. 2. Overlaps between records (10 to 1.5 sec.) are already removed from these files

  17. Two Trees: Migrating Fault Trees to Decision Trees for Real Time Fault Detection on International Space Station

    Science.gov (United States)

    Lee, Charles; Alena, Richard L.; Robinson, Peter

    2004-01-01

    We started from ISS fault trees example to migrate to decision trees, presented a method to convert fault trees to decision trees. The method shows that the visualizations of root cause of fault are easier and the tree manipulating becomes more programmatic via available decision tree programs. The visualization of decision trees for the diagnostic shows a format of straight forward and easy understands. For ISS real time fault diagnostic, the status of the systems could be shown by mining the signals through the trees and see where it stops at. The other advantage to use decision trees is that the trees can learn the fault patterns and predict the future fault from the historic data. The learning is not only on the static data sets but also can be online, through accumulating the real time data sets, the decision trees can gain and store faults patterns in the trees and recognize them when they come.

  18. Anisotropic electrical conduction in relation to the stacking disorder in graphite

    International Nuclear Information System (INIS)

    Tsuzuku, T.

    1979-01-01

    The in-plane and c-axis conduction behaviours of Kish graphite and of hot-worked pyrolytic graphite are discussed in relation to their structural perfection, special interest being focused onto the stacking fault disorder which appears in the form of extended basal dislocation ribbons. Analysis of the two-dimensional magneto-conductivity indicates that the carrier density of faulted specimens increases slowly with temperature (T) even below the degeneracy point of the carrier system, whereas the unfaulted ones do not. the c-axis resistivity (psub(c)) has been found to decrease with diminishing stacking disorder for a well-defined specimen group not containing such irregularities as microcracks. This verifies the applicability of the band model to the intrinsic psub(c) 's, in connection with the success of Ono's theory accounting for the wide-range scattering of past data. The discrepancy still remaining between the theoretical and experimental psub(c) vs T relationship, as well as the increase of the in-plane conduction carrier density with temperature, seems to be removed by assuming thermal liberation of the localized Tamm-state electrons from the stacking fault planes. (author)

  19. Vertically stacked nanocellulose tactile sensor.

    Science.gov (United States)

    Jung, Minhyun; Kim, Kyungkwan; Kim, Bumjin; Lee, Kwang-Jae; Kang, Jae-Wook; Jeon, Sanghun

    2017-11-16

    Paper-based electronic devices are attracting considerable attention, because the paper platform has unique attributes such as flexibility and eco-friendliness. Here we report on what is claimed to be the firstly fully integrated vertically-stacked nanocellulose-based tactile sensor, which is capable of simultaneously sensing temperature and pressure. The pressure and temperature sensors are operated using different principles and are stacked vertically, thereby minimizing the interference effect. For the pressure sensor, which utilizes the piezoresistance principle under pressure, the conducting electrode was inkjet printed on the TEMPO-oxidized-nanocellulose patterned with micro-sized pyramids, and the counter electrode was placed on the nanocellulose film. The pressure sensor has a high sensitivity over a wide range (500 Pa-3 kPa) and a high durability of 10 4 loading/unloading cycles. The temperature sensor combines various materials such as poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS), silver nanoparticles (AgNPs) and carbon nanotubes (CNTs) to form a thermocouple on the upper nanocellulose layer. The thermoelectric-based temperature sensors generate a thermoelectric voltage output of 1.7 mV for a temperature difference of 125 K. Our 5 × 5 tactile sensor arrays show a fast response, negligible interference, and durable sensing performance.

  20. Fault tolerant control for uncertain systems with parametric faults

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2006-01-01

    A fault tolerant control (FTC) architecture based on active fault diagnosis (AFD) and the YJBK (Youla, Jarb, Bongiorno and Kucera)parameterization is applied in this paper. Based on the FTC architecture, fault tolerant control of uncertain systems with slowly varying parametric faults...... is investigated. Conditions are given for closed-loop stability in case of false alarms or missing fault detection/isolation....

  1. Tectono-denudation process of Nanxiong fault and its relations to uranium metallogenesis

    International Nuclear Information System (INIS)

    Chen Yuehui

    1994-01-01

    A large mylonite zone is distributed on the foot wall of Nanxiong fault, which is parallel to the fault. On the hanging wall, there is a Meso-Cenozoic basin. As sedimentation centers are moved towards the side of the fault, the strata become more younger. By investigation of the mylonite zone along the profile on the foot wall of the fault, the author studies in detail various kinds of ductile deformation fabrics in mylonite such as S-C fabrics, rotational porphyroclasts and stretching lineation etc. In the light of the kinematic direction of deformation fabrics, together with the characteristics of brittle tectonites in the fault and the distribution of normal faults in the basin, the author believes that Nanxiong fault is a big-size denudation fault. According to the formation and evolution of the denudation fault, its rock and ore-controlling roles, the relations between the fault and uranium metallogenesis are also preliminarily discussed

  2. High Yield Chemical Vapor Deposition Growth of High Quality Large-Area AB Stacked Bilayer Graphene

    Science.gov (United States)

    Liu, Lixin; Zhou, Hailong; Cheng, Rui; Yu, Woo Jong; Liu, Yuan; Chen, Yu; Shaw, Jonathan; Zhong, Xing; Huang, Yu; Duan, Xiangfeng

    2012-01-01

    Bernal stacked (AB stacked) bilayer graphene is of significant interest for functional electronic and photonic devices due to the feasibility to continuously tune its band gap with a vertical electrical field. Mechanical exfoliation can be used to produce AB stacked bilayer graphene flakes but typically with the sizes limited to a few micrometers. Chemical vapor deposition (CVD) has been recently explored for the synthesis of bilayer graphene but usually with limited coverage and a mixture of AB and randomly stacked structures. Herein we report a rational approach to produce large-area high quality AB stacked bilayer graphene. We show that the self-limiting effect of graphene growth on Cu foil can be broken by using a high H2/CH4 ratio in a low pressure CVD process to enable the continued growth of bilayer graphene. A high temperature and low pressure nucleation step is found to be critical for the formation of bilayer graphene nuclei with high AB stacking ratio. A rational design of a two-step CVD process is developed for the growth of bilayer graphene with high AB stacking ratio (up to 90 %) and high coverage (up to 99 %). The electrical transport studies demonstrated that devices made of the as-grown bilayer graphene exhibit typical characteristics of AB stacked bilayer graphene with the highest carrier mobility exceeding 4,000 cm2/V·s at room temperature, comparable to that of the exfoliated bilayer graphene. PMID:22906199

  3. Metallogenetic characteristics of major fault in area No.212-318

    International Nuclear Information System (INIS)

    Zhang Yong

    1994-01-01

    Based on the distribution characteristics of major fault on the plan and assemblage form of major and subsidiary faults on the section, this paper expounds the relationship between major fault and uranium ore-formation, namely: different orders of fault structure control the spatial distribution of ore fields, ore deposits and ore bodies respectively, regional turning sites of the major fault control the ore fields; local turning sites of the major fault control ore deposits; different types of structural assemblages control ore bodies. Whether the matter compositions of fault structure are simple or not, it plays an absolutely important role in ore-formation. The complicated matter compositions of fault structures are favourable for ore-formation, conversely, simple compositions are unfavourable

  4. The untyped stack calculus and Bohm's theorem

    Directory of Open Access Journals (Sweden)

    Alberto Carraro

    2013-03-01

    Full Text Available The stack calculus is a functional language in which is in a Curry-Howard correspondence with classical logic. It enjoys confluence but, as well as Parigot's lambda-mu, does not admit the Bohm Theorem, typical of the lambda-calculus. We present a simple extension of stack calculus which is for the stack calculus what Saurin's Lambda-mu is for lambda-mu.

  5. Flexural characteristics of a stack leg

    International Nuclear Information System (INIS)

    Cook, J.

    1979-06-01

    A 30 MV tandem Van de Graaff accelerator is at present under construction at Daresbury Laboratory. The insulating stack of the machine is of modular construction, each module being 860 mm in length. Each live section stack module contains 8 insulating legs mounted between bulkhead rings. The design, fabrication (from glass discs bonded to stainless steel discs using an epoxy film adhesive) and testing of the stack legs is described. (U.K.)

  6. Precise tremor source locations and amplitude variations along the lower-crustal central San Andreas Fault

    Science.gov (United States)

    Shelly, David R.; Hardebeck, Jeanne L.

    2010-01-01

    We precisely locate 88 tremor families along the central San Andreas Fault using a 3D velocity model and numerous P and S wave arrival times estimated from seismogram stacks of up to 400 events per tremor family. Maximum tremor amplitudes vary along the fault by at least a factor of 7, with by far the strongest sources along a 25 km section of the fault southeast of Parkfield. We also identify many weaker tremor families, which have largely escaped prior detection. Together, these sources extend 150 km along the fault, beneath creeping, transitional, and locked sections of the upper crustal fault. Depths are mostly between 18 and 28 km, in the lower crust. Epicenters are concentrated within 3 km of the surface trace, implying a nearly vertical fault. A prominent gap in detectible activity is located directly beneath the region of maximum slip in the 2004 magnitude 6.0 Parkfield earthquake.

  7. Rolling bearing fault diagnosis using adaptive deep belief network with dual-tree complex wavelet packet.

    Science.gov (United States)

    Shao, Haidong; Jiang, Hongkai; Wang, Fuan; Wang, Yanan

    2017-07-01

    Automatic and accurate identification of rolling bearing fault categories, especially for the fault severities and compound faults, is a challenge in rotating machinery fault diagnosis. For this purpose, a novel method called adaptive deep belief network (DBN) with dual-tree complex wavelet packet (DTCWPT) is developed in this paper. DTCWPT is used to preprocess the vibration signals to refine the fault characteristics information, and an original feature set is designed from each frequency-band signal of DTCWPT. An adaptive DBN is constructed to improve the convergence rate and identification accuracy with multiple stacked adaptive restricted Boltzmann machines (RBMs). The proposed method is applied to the fault diagnosis of rolling bearings. The results confirm that the proposed method is more effective than the existing methods. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  8. ooi: OpenStack OCCI interface

    Directory of Open Access Journals (Sweden)

    Álvaro López García

    2016-01-01

    Full Text Available In this document we present an implementation of the Open Grid Forum’s Open Cloud Computing Interface (OCCI for OpenStack, namely ooi (Openstack occi interface, 2015  [1]. OCCI is an open standard for management tasks over cloud resources, focused on interoperability, portability and integration. ooi aims to implement this open interface for the OpenStack cloud middleware, promoting interoperability with other OCCI-enabled cloud management frameworks and infrastructures. ooi focuses on being non-invasive with a vanilla OpenStack installation, not tied to a particular OpenStack release version.

  9. ooi: OpenStack OCCI interface

    Science.gov (United States)

    López García, Álvaro; Fernández del Castillo, Enol; Orviz Fernández, Pablo

    In this document we present an implementation of the Open Grid Forum's Open Cloud Computing Interface (OCCI) for OpenStack, namely ooi (Openstack occi interface, 2015) [1]. OCCI is an open standard for management tasks over cloud resources, focused on interoperability, portability and integration. ooi aims to implement this open interface for the OpenStack cloud middleware, promoting interoperability with other OCCI-enabled cloud management frameworks and infrastructures. ooi focuses on being non-invasive with a vanilla OpenStack installation, not tied to a particular OpenStack release version.

  10. Self-Assembly of Ureido-Pyrimidinone Dimers into One-Dimensional Stacks by Lateral Hydrogen Bonding

    NARCIS (Netherlands)

    Nieuwenhuizen, Marko M.L.; de Greef, Tom F.A.; van der Bruggen, Rob L.J.; Paulusse, Jos Marie Johannes; Appel, Wilco P.J.; Smulders, Maarten M.J.; Sijbesma, Rint P.; Meijer, E.W.

    2010-01-01

    Ureido-pyrimidinone (UPy) dimers substituted with an additional urea functionality self-assemble into one-dimensional stacks in various solvents through lateral non-covalent interactions. 1H NMR and DOSY studies in CDCl3 suggest the formation of short stacks (<10), whereas temperature-dependent

  11. Ten kilometer vertical Moho offset and shallow velocity contrast along the Denali fault zone from double-difference tomography, receiver functions, and fault zone head waves

    Science.gov (United States)

    Allam, A. A.; Schulte-Pelkum, V.; Ben-Zion, Y.; Tape, C.; Ruppert, N.; Ross, Z. E.

    2017-11-01

    We examine the structure of the Denali fault system in the crust and upper mantle using double-difference tomography, P-wave receiver functions, and analysis (spatial distribution and moveout) of fault zone head waves. The three methods have complementary sensitivity; tomography is sensitive to 3D seismic velocity structure but smooths sharp boundaries, receiver functions are sensitive to (quasi) horizontal interfaces, and fault zone head waves are sensitive to (quasi) vertical interfaces. The results indicate that the Mohorovičić discontinuity is vertically offset by 10 to 15 km along the central 600 km of the Denali fault in the imaged region, with the northern side having shallower Moho depths around 30 km. An automated phase picker algorithm is used to identify 1400 events that generate fault zone head waves only at near-fault stations. At shorter hypocentral distances head waves are observed at stations on the northern side of the fault, while longer propagation distances and deeper events produce head waves on the southern side. These results suggest a reversal of the velocity contrast polarity with depth, which we confirm by computing average 1D velocity models separately north and south of the fault. Using teleseismic events with M ≥ 5.1, we obtain 31,400 P receiver functions and apply common-conversion-point stacking. The results are migrated to depth using the derived 3D tomography model. The imaged interfaces agree with the tomography model, showing a Moho offset along the central Denali fault and also the sub-parallel Hines Creek fault, a suture zone boundary 30 km to the north. To the east, this offset follows the Totschunda fault, which ruptured during the M7.9 2002 earthquake, rather than the Denali fault itself. The combined results suggest that the Denali fault zone separates two distinct crustal blocks, and that the Totschunda and Hines Creeks segments are important components of the fault and Cretaceous-aged suture zone structure.

  12. Stacks of SPS Dipole Magnets

    CERN Multimedia

    1974-01-01

    Stacks of SPS Dipole Magnets ready for installation in the tunnel. The SPS uses a separated function lattice with dipoles for bending and quadrupoles for focusing. The 6.2 m long normal conducting dipoles are of H-type with coils that are bent-up at the ends. There are two types, B1 (total of 360) and B2 (384). Both are for a maximum field of 1.8 Tesla and have the same outer dimensions (450x800 mm2 vxh) but with different gaps (B1: 39x129 mm2, B2: 52x92 mm2) tailored to the beam size. The yoke, made of 1.5 mm thick laminations, consists of an upper and a lower half joined together in the median plane once the coils have been inserted.

  13. California dreaming?[PEM stacks

    Energy Technology Data Exchange (ETDEWEB)

    Crosse, J.

    2002-06-01

    Hyundai's Santa Fe FCEV will be on sale by the end of 2002. Hyundai uses PEM stacks that are manufactured by International Fuel Cells (IFC), a division of United Technologies. Santa Fe is equipped with a 65 kW electric powertrain of Enova systems and Shell's new gasoline reformer called Hydrogen Source. Eugene Jang, Senior Engineer - Fuel Cell and Materials at Hyundai stated that the compressor related losses on IFC system are below 3%. The maximum speed offered by the vehicle is estimated as 123km/hr while the petrol equivalent fuel consumption is quoted between 5.6L/100 km and 4.8L/100 km. Santa Fe is a compact vehicle offering better steering response and a pleasant drive. (author)

  14. Anti-solvent derived non-stacked reduced graphene oxide for high performance supercapacitors.

    Science.gov (United States)

    Yoon, Yeoheung; Lee, Keunsik; Baik, Chul; Yoo, Heejoun; Min, Misook; Park, Younghun; Lee, Sae Mi; Lee, Hyoyoung

    2013-08-27

    An anti-solvent for graphene oxide (GO), hexane, is introduced to increase the surface area and the pore volume of the non-stacked GO/reduced GO 3D structure and allows the formation of a highly crumpled non-stacked GO powder, which clearly shows ideal supercapacitor behavior. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Computer aided fault tree construction for electrical systems

    International Nuclear Information System (INIS)

    Fussell, J.B.

    1975-01-01

    A technique is presented for automated construction of the Boolean failure logic diagram, called the fault tree, for electrical systems. The method is a technique for synthesizing a fault tree from system-independent component characteristics. Terminology is defined and heuristic examples are given for all phases of the model. The computer constructed fault trees are in conventional format, use conventional symbols, and are deductively constructed from the main failure of interest to the individual component failures. The synthesis technique is generally applicable to automated fault tree construction for other types of systems

  16. Fault tree graphics

    International Nuclear Information System (INIS)

    Bass, L.; Wynholds, H.W.; Porterfield, W.R.

    1975-01-01

    Described is an operational system that enables the user, through an intelligent graphics terminal, to construct, modify, analyze, and store fault trees. With this system, complex engineering designs can be analyzed. This paper discusses the system and its capabilities. Included is a brief discussion of fault tree analysis, which represents an aspect of reliability and safety modeling

  17. Vector Fields and Flows on Differentiable Stacks

    DEFF Research Database (Denmark)

    A. Hepworth, Richard

    2009-01-01

    This paper introduces the notions of vector field and flow on a general differentiable stack. Our main theorem states that the flow of a vector field on a compact proper differentiable stack exists and is unique up to a uniquely determined 2-cell. This extends the usual result on the existence...... of vector fields....

  18. Project W-420 stack monitoring system upgrades

    International Nuclear Information System (INIS)

    CARPENTER, K.E.

    1999-01-01

    This project will execute the design, procurement, construction, startup, and turnover activities for upgrades to the stack monitoring system on selected Tank Waste Remediation System (TWRS) ventilation systems. In this plan, the technical, schedule, and cost baselines are identified, and the roles and responsibilities of project participants are defined for managing the Stack Monitoring System Upgrades, Project W-420

  19. 40 CFR 61.44 - Stack sampling.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Stack sampling. 61.44 Section 61.44 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL... Firing § 61.44 Stack sampling. (a) Sources subject to § 61.42(b) shall be continuously sampled, during...

  20. Learning OpenStack networking (Neutron)

    CERN Document Server

    Denton, James

    2014-01-01

    If you are an OpenStack-based cloud operator with experience in OpenStack Compute and nova-network but are new to Neutron networking, then this book is for you. Some networking experience is recommended, and a physical network infrastructure is required to provide connectivity to instances and other network resources configured in the book.

  1. How do normal faults grow?

    OpenAIRE

    Blækkan, Ingvild; Bell, Rebecca; Rotevatn, Atle; Jackson, Christopher; Tvedt, Anette

    2018-01-01

    Faults grow via a sympathetic increase in their displacement and length (isolated fault model), or by rapid length establishment and subsequent displacement accrual (constant-length fault model). To test the significance and applicability of these two models, we use time-series displacement (D) and length (L) data extracted for faults from nature and experiments. We document a range of fault behaviours, from sympathetic D-L fault growth (isolated growth) to sub-vertical D-L growth trajectorie...

  2. Characterization of leaky faults

    International Nuclear Information System (INIS)

    Shan, Chao.

    1990-05-01

    Leaky faults provide a flow path for fluids to move underground. It is very important to characterize such faults in various engineering projects. The purpose of this work is to develop mathematical solutions for this characterization. The flow of water in an aquifer system and the flow of air in the unsaturated fault-rock system were studied. If the leaky fault cuts through two aquifers, characterization of the fault can be achieved by pumping water from one of the aquifers, which are assumed to be horizontal and of uniform thickness. Analytical solutions have been developed for two cases of either a negligibly small or a significantly large drawdown in the unpumped aquifer. Some practical methods for using these solutions are presented. 45 refs., 72 figs., 11 tabs

  3. Solar system fault detection

    Science.gov (United States)

    Farrington, R.B.; Pruett, J.C. Jr.

    1984-05-14

    A fault detecting apparatus and method are provided for use with an active solar system. The apparatus provides an indication as to whether one or more predetermined faults have occurred in the solar system. The apparatus includes a plurality of sensors, each sensor being used in determining whether a predetermined condition is present. The outputs of the sensors are combined in a pre-established manner in accordance with the kind of predetermined faults to be detected. Indicators communicate with the outputs generated by combining the sensor outputs to give the user of the solar system and the apparatus an indication as to whether a predetermined fault has occurred. Upon detection and indication of any predetermined fault, the user can take appropriate corrective action so that the overall reliability and efficiency of the active solar system are increased.

  4. Status of MCFC stack technology at IHI

    Energy Technology Data Exchange (ETDEWEB)

    Hosaka, M.; Morita, T.; Matsuyama, T.; Otsubo, M. [Ishikawajima-Harima Heavy Industries Co., Ltd., Tokyo (Japan)

    1996-12-31

    The molten carbonate fuel cell (MCFC) is a promising option for highly efficient power generation possible to enlarge. IHI has been studying parallel flow MCFC stacks with internal manifolds that have a large electrode area of 1m{sup 2}. IHI will make two 250 kW stacks for MW plant, and has begun to make cell components for the plant. To improve the stability of stack, soft corrugated plate used in the separator has been developed, and a way of gathering current from stacks has been studied. The DC output potential of the plant being very high, the design of electric insulation will be very important. A 20 kW short stack test was conducted in 1995 FY to certificate some of the improvements and components of the MW plant. These activities are presented below.

  5. Modular fuel-cell stack assembly

    Science.gov (United States)

    Patel, Pinakin

    2010-07-13

    A fuel cell assembly having a plurality of fuel cells arranged in a stack. An end plate assembly abuts the fuel cell at an end of said stack. The end plate assembly has an inlet area adapted to receive an exhaust gas from the stack, an outlet area and a passage connecting the inlet area and outlet area and adapted to carry the exhaust gas received at the inlet area from the inlet area to the outlet area. A further end plate assembly abuts the fuel cell at a further opposing end of the stack. The further end plate assembly has a further inlet area adapted to receive a further exhaust gas from the stack, a further outlet area and a further passage connecting the further inlet area and further outlet area and adapted to carry the further exhaust gas received at the further inlet area from the further inlet area to the further outlet area.

  6. Electromagnetic Imaging of Fluids in the San Andreas Fault; FINAL

    International Nuclear Information System (INIS)

    Martyn Unsworth

    2002-01-01

    OAK 270 - Magnetotelluric data were collected on six profiles across the san Andreas Fault at Cholame,Parkfield, and Hollister in Central California. On each profile, high electrical resistivities were imaged west of the fault, and are due to granitic rocks of the Salinian block. East of the fault, lower electrical resistivities are associated with rocks of the Fanciscan formation. On the seismically active Parkfield and Hollister segments, a region of low resistivity was found in the fault zone that extends to a depth of several kilometers. This is due to a zone of fracturing (the damaged zone) that has been infiltrated by saline ground water. The shallowest micro-earthquakers occur at a depth that is coincident with the base of the low resistivity wedge. This strongly suggests that above this depth, the fault rocks are too weak to accumulate sufficient stress for earthquake rupture to occur and fault motion is accommodated through aseismic creep

  7. Fault Management of a Cold Dielectric HTS Power Transmission Cable

    International Nuclear Information System (INIS)

    Maguire, J; Allais, A; Yuan, J; Schmidt, F; Hamber, F; Welsh, Tom

    2006-01-01

    High temperature superconductor (HTS) power transmission cables offer significant advantages in power density over conventional copper-based cables. As with conventional cables, HTS cables must be safe and reliable when abnormal conditions, such as local and through faults, occur in the power grid. Due to the unique characteristics of HTS power cables, the fault management of an HTS cable is different from that of a conventional cable. Issues, such as nitrogen bubble formation within lapped dielectric material, need to be addressed. This paper reviews the efforts that have been performed to study the fault conditions of a cold dielectric HTS power cable. As a result of the efforts, a fault management scheme has been developed, which provides both local and through faults system protection. Details of the fault management scheme with examples are presented

  8. THE OCCURRENCE OF FAULT BARS IN THE PLUMAGE OF NESTLING OSPREYS

    NARCIS (Netherlands)

    MACHMER, MM; ESSELINK, H; STEEGER, C; YDENBERG, RC

    1992-01-01

    We document the occurrence of fault bars in a population of nestling Ospreys Pandion haliaetus under natural conditions. Ospreys had an average of 9.9 fault bars on their rectrices, however variation was large. Fault bar formation declined linearly with age and increased symmetrically from outer to

  9. Faulting in mudrocks: the selection of potential research sites

    International Nuclear Information System (INIS)

    Alexander, J.

    1990-01-01

    The British Geological Survey, in cooperation with Ismes of Italy, has carried out a research programme into faults through clay formations. The research programme commenced in April 1986 and work started at the Down Ampney site in February 1987

  10. Probing Temperature Inside Planar SOFC Short Stack, Modules, and Stack Series

    Science.gov (United States)

    Yu, Rong; Guan, Wanbing; Zhou, Xiao-Dong

    2017-02-01

    Probing temperature inside a solid oxide fuel cell (SOFC) stack lies at the heart of the development of high-performance and stable SOFC systems. In this article, we report our recent work on the direct measurements of the temperature in three types of SOFC systems: a 5-cell short stack, a 30-cell stack module, and a stack series consisting of two 30-cell stack modules. The dependence of temperature on the gas flow rate and current density was studied under a current sweep or steady-state operation. During the current sweep, the temperature inside the 5-cell stack decreased with increasing current, while it increased significantly at the bottom and top of the 30-cell stack. During a steady-state operation, the temperature of the 5-cell stack was stable while it was increased in the 30-cell stack. In the stack series, the maximum temperature gradient reached 190°C when the gas was not preheated. If the gas was preheated and the temperature gradient was reduced to 23°C in the stack series with the presence of a preheating gas and segmented temperature control, this resulted in a low degradation rate.

  11. Fault zone processes in mechanically layered mudrock and chalk

    Science.gov (United States)

    Ferrill, David A.; Evans, Mark A.; McGinnis, Ronald N.; Morris, Alan P.; Smart, Kevin J.; Wigginton, Sarah S.; Gulliver, Kirk D. H.; Lehrmann, Daniel; de Zoeten, Erich; Sickmann, Zach

    2017-04-01

    A 1.5 km long natural cliff outcrop of nearly horizontal Eagle Ford Formation in south Texas exposes northwest and southeast dipping normal faults with displacements of 0.01-7 m cutting mudrock, chalk, limestone, and volcanic ash. These faults provide analogs for both natural and hydraulically-induced deformation in the productive Eagle Ford Formation - a major unconventional oil and gas reservoir in south Texas, U.S.A. - and other mechanically layered hydrocarbon reservoirs. Fault dips are steep to vertical through chalk and limestone beds, and moderate through mudrock and clay-rich ash, resulting in refracted fault profiles. Steeply dipping fault segments contain rhombohedral calcite veins that cross the fault zone obliquely, parallel to shear segments in mudrock. The vertical dimensions of the calcite veins correspond to the thickness of offset competent beds with which they are contiguous, and the slip parallel dimension is proportional to fault displacement. Failure surface characteristics, including mixed tensile and shear segments, indicate hybrid failure in chalk and limestone, whereas shear failure predominates in mudrock and ash beds - these changes in failure mode contribute to variation in fault dip. Slip on the shear segments caused dilation of the steeper hybrid segments. Tabular sheets of calcite grew by repeated fault slip, dilation, and cementation. Fluid inclusion and stable isotope geochemistry analyses of fault zone cements indicate episodic reactivation at 1.4-4.2 km depths. The results of these analyses document a dramatic bed-scale lithologic control on fault zone architecture that is directly relevant to the development of porosity and permeability anisotropy along faults.

  12. The impact of stack geometry and mean pressure on cold end temperature of stack in thermoacoustic refrigeration systems

    Science.gov (United States)

    Wantha, Channarong

    2018-02-01

    This paper reports on the experimental and simulation studies of the influence of stack geometries and different mean pressures on the cold end temperature of the stack in the thermoacoustic refrigeration system. The stack geometry was tested, including spiral stack, circular pore stack and pin array stack. The results of this study show that the mean pressure of the gas in the system has a significant impact on the cold end temperature of the stack. The mean pressure of the gas in the system corresponds to thermal penetration depth, which results in a better cold end temperature of the stack. The results also show that the cold end temperature of the pin array stack decreases more than that of the spiral stack and circular pore stack geometry by approximately 63% and 70%, respectively. In addition, the thermal area and viscous area of the stack are analyzed to explain the results of such temperatures of thermoacoustic stacks.

  13. Fault and joint geometry at Raft River Geothermal Area, Idaho

    Science.gov (United States)

    Guth, L. R.; Bruhn, R. L.; Beck, S. L.

    1981-07-01

    Raft River geothermal reservoir is formed by fractures in sedimentary strata of the Miocene and Pliocene salt lake formation. The fracturing is most intense at the base of the salt lake formation, along a decollement that dips eastward at less than 50 on top of metamorphosed precambrian and lower paleozoic rocks. Core taken from less than 200 m above the decollement contains two sets of normal faults. The major set of faults dips between 500 and 700. These faults occur as conjugate pairs that are bisected by vertical extension fractures. The second set of faults dips 100 to 200 and may parallel part of the basal decollement or reflect the presence of listric normal faults in the upper plate. Surface joints form two suborthogonal sets that dip vertically. East-northeast-striking joints are most frequent on the limbs of the Jim Sage anticline, a large fold that is associated with the geothermal field.

  14. Passive recording of an active transform, an example from the Levant continental margin and the Dead Sea Fault

    Science.gov (United States)

    Lang, Guy; Lazar, Michael; Schattner, Uri

    2017-04-01

    Transform faults accommodate lateral motion between two adjacent plates. Records of plate motion and consequent boundary development on land is, at times, scarce and limited to structures along the fault axis. Investigation of a passive continental margin adjacent to the plate boundary might broaden the scope and provide estimates for its structural development. To examine this hypothesis, we analyzed depth and time migrated 3D seismic data together with four boreholes located along the southern Levant continental margin, ca. 100 Km from the continental Dead Sea fault (DSF). The analysis focus on the Plio-Pleistocene sequence, a key period in the development of the DSF. It includes formation of structural maps, stacking pattern investigation and calculation of sedimentation rates based on decompacted 3D depth data. These, in turn, enabled the reconstruction of margin development. This includes Messinian-earliest Zanclean NNE-SSW sinistral strike-slip faulting followed by Zanclean-Late Gelasian syn-depositional folding striking in the same direction. Abrupt change is marked by the Top Gelasian surface that shows indications of regional mass slumping. Successive Mid-Late Pleistocene progradation marks a basinward shift of the depocenter. Progradation controls margin sedimentation rates during the mid-late Pleistocene. These were found to increase throughout the whole Plio-Pleistocene, in contrast to reported sediment discharge from the Nile, which was shown to decrease after the Gelasian. Correlations to onshore findings, suggest that the continental margin records strain localization on the DSF during the Pliocene-Gelasian. This trend peaked at 1.8 Ma when short wavelength strain ceased along the margin, and differential subsidence commenced basinwards. This is attributed to consequent deepening of the DSF plate boundary.

  15. Report on AECB consultative document C-70: The use of fault trees in licensing submissions

    International Nuclear Information System (INIS)

    1984-01-01

    The Atomic Energy Control Board (AECB) has issued Consultative Document C-70, 'The Use of Fault Trees in Licensing Submissions', for public comment. The Advisory Committee on Nuclear Safety (ACNS) has examined this document and ACNS members have met with AECB staff and representatives of the nuclear industry to discuss it. The ACNS presents its comments and recommendations in this report. The consultative document defines a fault tree as a hierarchically-structured graphical representation of system failures and their potential causes. The document then states certain basic characteristics or attributes which fault trees should possess, and certain conditions affecting the use of fault trees. It defines fault tree fundamentals, sets criteria for the application of fault trees to systems and defines ground rules for a fault tree format. Finally, in two appendices, it includes specific rules for fault tree symbols and fault tree description files for computer use. The appendices are referred to in the text as 'acceptable' standards or methods

  16. Five stacks over the Danube

    International Nuclear Information System (INIS)

    Anon.

    1998-01-01

    Following the departure of Communism, Hungary adopted the most ambitious privatisation programme of all the eastern European countries. Within a year the state electricity company, MVM, and the oil and gas company, MOL, were prepared for sale and a consequent injection of foreign capital. Control of prices by central government inhibited investment initially but a new legal framework put in place in 1995 introduced a pricing regime more attractive to external investors. Particular interest was shown in the 2,200MW mixed heavy oil and natural gas power plant at Dunamenti on the Danube, characterised by its five stacks of varying height which reflect the changing technology employed at the plant. The bid was won by Tractabel of Belgium who have been highly successful in improving plant efficiency. However, the impact of privatisation is now being felt in uncertainty over fuel supply. Removing such uncertainty in order to maintain existing investment and provide the additional 4000MW of generating capacity needed to keep pace with demand, is a major problem which the incoming government faces. (UK)

  17. Fault Management Metrics

    Science.gov (United States)

    Johnson, Stephen B.; Ghoshal, Sudipto; Haste, Deepak; Moore, Craig

    2017-01-01

    This paper describes the theory and considerations in the application of metrics to measure the effectiveness of fault management. Fault management refers here to the operational aspect of system health management, and as such is considered as a meta-control loop that operates to preserve or maximize the system's ability to achieve its goals in the face of current or prospective failure. As a suite of control loops, the metrics to estimate and measure the effectiveness of fault management are similar to those of classical control loops in being divided into two major classes: state estimation, and state control. State estimation metrics can be classified into lower-level subdivisions for detection coverage, detection effectiveness, fault isolation and fault identification (diagnostics), and failure prognosis. State control metrics can be classified into response determination effectiveness and response effectiveness. These metrics are applied to each and every fault management control loop in the system, for each failure to which they apply, and probabilistically summed to determine the effectiveness of these fault management control loops to preserve the relevant system goals that they are intended to protect.

  18. Fault isolability conditions for linear systems with additive faults

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Stoustrup, Jakob

    2006-01-01

    In this paper, we shall show that an unlimited number of additive single faults can be isolated under mild conditions if a general isolation scheme is applied. Multiple faults are also covered. The approach is algebraic and is based on a set representation of faults, where all faults within a set...

  19. Fault Analysis in Cryptography

    CERN Document Server

    Joye, Marc

    2012-01-01

    In the 1970s researchers noticed that radioactive particles produced by elements naturally present in packaging material could cause bits to flip in sensitive areas of electronic chips. Research into the effect of cosmic rays on semiconductors, an area of particular interest in the aerospace industry, led to methods of hardening electronic devices designed for harsh environments. Ultimately various mechanisms for fault creation and propagation were discovered, and in particular it was noted that many cryptographic algorithms succumb to so-called fault attacks. Preventing fault attacks without

  20. Single and combined fault diagnosis of reciprocating compressor valves using a hybrid deep belief network

    NARCIS (Netherlands)

    Tran, Van Tung; Thobiani, Faisal Al; Tinga, Tiedo; Ball, Andrew David; Niu, Gang

    2017-01-01

    In this paper, a hybrid deep belief network is proposed to diagnose single and combined faults of suction and discharge valves in a reciprocating compressor. This hybrid integrates the deep belief network structured by multiple stacked restricted Boltzmann machines for pre-training and simplified

  1. Fault tolerant control based on active fault diagnosis

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik

    2005-01-01

    An active fault diagnosis (AFD) method will be considered in this paper in connection with a Fault Tolerant Control (FTC) architecture based on the YJBK parameterization of all stabilizing controllers. The architecture consists of a fault diagnosis (FD) part and a controller reconfiguration (CR......) part. The FTC architecture can be applied for additive faults, parametric faults, and for system structural changes. Only parametric faults will be considered in this paper. The main focus in this paper is on the use of the new approach of active fault diagnosis in connection with FTC. The active fault...... diagnosis approach is based on including an auxiliary input in the system. A fault signature matrix is introduced in connection with AFD, given as the transfer function from the auxiliary input to the residual output. This can be considered as a generalization of the passive fault diagnosis case, where...

  2. Dynamical stability of slip-stacking particles

    Energy Technology Data Exchange (ETDEWEB)

    Eldred, Jeffrey; Zwaska, Robert

    2014-09-01

    We study the stability of particles in slip-stacking configuration, used to nearly double proton beam intensity at Fermilab. We introduce universal area factors to calculate the available phase space area for any set of beam parameters without individual simulation. We find perturbative solutions for stable particle trajectories. We establish Booster beam quality requirements to achieve 97% slip-stacking efficiency. We show that slip-stacking dynamics directly correspond to the driven pendulum and to the system of two standing-wave traps moving with respect to each other.

  3. Text-Filled Stacked Area Graphs

    DEFF Research Database (Denmark)

    Kraus, Martin

    2011-01-01

    -filled stacked area graphs; i.e., graphs that feature stacked areas that are filled with small-typed text. Since these graphs allow for computing the text layout automatically, it is possible to include large amounts of textual detail with very little effort. We discuss the most important challenges and some...... solutions for the design of text-filled stacked area graphs with the help of an exemplary visualization of the genres, publication years, and titles of a database of several thousand PC games....

  4. Tunable electro-optic filter stack

    Science.gov (United States)

    Fontecchio, Adam K.; Shriyan, Sameet K.; Bellingham, Alyssa

    2017-09-05

    A holographic polymer dispersed liquid crystal (HPDLC) tunable filter exhibits switching times of no more than 20 microseconds. The HPDLC tunable filter can be utilized in a variety of applications. An HPDLC tunable filter stack can be utilized in a hyperspectral imaging system capable of spectrally multiplexing hyperspectral imaging data acquired while the hyperspectral imaging system is airborne. HPDLC tunable filter stacks can be utilized in high speed switchable optical shielding systems, for example as a coating for a visor or an aircraft canopy. These HPDLC tunable filter stacks can be fabricated using a spin coating apparatus and associated fabrication methods.

  5. Integrated fuel cell stack shunt current prevention arrangement

    Energy Technology Data Exchange (ETDEWEB)

    Roche, Robert P. (Cheshire, CT); Nowak, Michael P. (Bolton, CT)

    1992-01-01

    A fuel cell stack includes a plurality of fuel cells juxtaposed with one another in the stack and each including a pair of plate-shaped anode and cathode electrodes that face one another, and a quantity of liquid electrolyte present at least between the electrodes. A separator plate is interposed between each two successive electrodes of adjacent ones of the fuel cells and is unified therewith into an integral separator plate. Each integral separator plate is provided with a circumferentially complete barrier that prevents flow of shunt currents onto and on an outer peripheral surface of the separator plate. This barrier consists of electrolyte-nonwettable barrier members that are accommodated, prior to the formation of the integral separator plate, in corresponding edge recesses situated at the interfaces between the electrodes and the separator plate proper. Each barrier member extends over the entire length of the associated marginal portion and is flush with the outer periphery of the integral separator plate. This barrier also prevents cell-to-cell migration of any electrolyte that may be present at the outer periphery of the integral separator plate while the latter is incorporated in the fuel cell stack.

  6. Quaternary Fault Lines

    Data.gov (United States)

    Department of Homeland Security — This data set contains locations and information on faults and associated folds in the United States that are believed to be sources of M>6 earthquakes during the...

  7. Pre-stack estimation of time-lapse seismic velocity changes : an example from the Sleipner CO2-sequestration project

    International Nuclear Information System (INIS)

    Ghaderi, A.; Landro, M.; Ghaderi, A.

    2005-01-01

    Carbon dioxide (CO 2 ) is being injected into a shallow sand formation at around a 1,000 metre depth at the Sleipner Field located in the North Sea. It is expected that the CO 2 injected in the bottom of the formation, will form a plume consisting of CO 2 accumulating in thin lenses during migration up through the reservoir. Several studies have been published using stacked seismic data from 1994, 1999, 2001 and 2002. A thorough analysis of post-stack seismic data from the Sleipner CO2-Sequestration Pilot Project was conducted. Interpretation of seismic data is usually done on post-stack data. For a given subsurface reflection point, seismic data are acquired for various incidence angles, typically 40 angles. These 40 seismic signals are stacked together in order to reduce noise. The term pre-stack refers to seismic data prior to this step. For hydrocarbon-related 4-dimensional seismic studies, travel time shift estimations have been used. This paper compared pre-stack and post-stack estimation of average velocity changes based on measured 4-dimensional travel time shifts. It is more practical to compare estimated velocity changes than the actual travel time changes, since the time shifts vary with offset for pre-stack time-lapse seismic analysis. It was concluded that the pre-stack method gives smaller velocity changes when estimated between two key horizons. Therefore, pre-stack travel time analysis in addition to conventional post-stack analysis is recommended. 6 refs., 12 figs

  8. Evolution of the Puente Hills Thrust Fault

    Science.gov (United States)

    Bergen, K. J.; Shaw, J. H.; Dolan, J. F.

    2013-12-01

    This study aims to assess the evolution of the blind Puente Hills thrust fault system (PHT) by determining its age of initiation, lateral propagation history, and changes in slip rate over time. The PHT presents one of the largest seismic hazards in the United States, given its location beneath downtown Los Angeles. The PHT is comprised of three fault segments: the Los Angeles (LA), Santa Fe Springs (SFS), and Coyote Hills (CH). The LA and SFS segments are characterized by growth stratigraphy where folds formed by uplift on the fault segments have been continually buried by sediment from the Los Angeles and San Gabriel rivers. The CH segment has developed topography and is characterized by onlapping growth stratigraphy. This depositional setting gives us the unique opportunity to measure uplift on the LA and SFS fault segments, and minimum uplift on the CH fault segment, as the difference in sediment thicknesses across the buried folds. We utilize depth converted oil industry seismic reflection data to image the fold geometries. Identifying time-correlative stratigraphic markers for slip rate determination in the basin has been a problem for researchers in the past, however, as the faunal assemblages observed in wells are time-transgressive by nature. To overcome this, we utilize the sequence stratigraphic model and well picks of Ponti et al. (2007) as a basis for mapping time-correlative sequence boundaries throughout our industry seismic reflection data from the present to the Pleistocene. From the Pleistocene to Miocene we identify additional sequence boundaries in our seismic reflection data from imaged sequence geometries and by correlating industry well formation tops. The sequence and formation top picks are then used to build 3-dimensional surfaces in the modeling program Gocad. From these surfaces we measure the change in thicknesses across the folds to obtain uplift rates between each sequence boundary. Our results show three distinct phases of

  9. Alternative model of thrust-fault propagation

    Science.gov (United States)

    Eisenstadt, Gloria; de Paor, Declan G.

    1987-07-01

    A widely accepted explanation for the geometry of thrust faults is that initial failures occur on deeply buried planes of weak rock and that thrust faults propagate toward the surface along a staircase trajectory. We propose an alternative model that applies Gretener's beam-failure mechanism to a multilayered sequence. Invoking compatibility conditions, which demand that a thrust propagate both upsection and downsection, we suggest that ramps form first, at shallow levels, and are subsequently connected by flat faults. This hypothesis also explains the formation of many minor structures associated with thrusts, such as backthrusts, wedge structures, pop-ups, and duplexes, and provides a unified conceptual framework in which to evaluate field observations.

  10. Characterization of Piezoelectric Stacks for Space Applications

    Science.gov (United States)

    Sherrit, Stewart; Jones, Christopher; Aldrich, Jack; Blodget, Chad; Bao, Xiaoqi; Badescu, Mircea; Bar-Cohen, Yoseph

    2008-01-01

    Future NASA missions are increasingly seeking to actuate mechanisms to precision levels in the nanometer range and below. Co-fired multilayer piezoelectric stacks offer the required actuation precision that is needed for such mechanisms. To obtain performance statistics and determine reliability for extended use, sets of commercial PZT stacks were tested in various AC and DC conditions at both nominal and high temperatures and voltages. In order to study the lifetime performance of these stacks, five actuators were driven sinusoidally for up to ten billion cycles. An automated data acquisition system was developed and implemented to monitor each stack's electrical current and voltage waveforms over the life of the test. As part of the monitoring tests, the displacement, impedance, capacitance and leakage current were measured to assess the operation degradation. This paper presents some of the results of this effort.

  11. The stack on software and sovereignty

    CERN Document Server

    Bratton, Benjamin H

    2016-01-01

    A comprehensive political and design theory of planetary-scale computation proposing that The Stack -- an accidental megastructure -- is both a technological apparatus and a model for a new geopolitical architecture.

  12. Development of Auto-Stacking Warehouse Truck

    Directory of Open Access Journals (Sweden)

    Kuo-Hsien Hsia

    2018-03-01

    Full Text Available Warehouse automation is a very important issue for the promotion of traditional industries. For the production of larger and stackable products, it is usually necessary to operate a fork-lifter for the stacking and storage of the products by a skilled person. The general autonomous warehouse-truck does not have the ability of stacking objects. In this paper, we develop a prototype of auto-stacking warehouse-truck that can work without direct operation by a skill person. With command made by an RFID card, the stacker truck can take the packaged product to the warehouse on the prior-planned route and store it in a stacking way in the designated storage area, or deliver the product to the shipping area or into the container from the storage area. It can significantly reduce the manpower requirements of the skilled-person of forklift technician and improve the safety of the warehousing area.

  13. Fault lubrication during earthquakes.

    Science.gov (United States)

    Di Toro, G; Han, R; Hirose, T; De Paola, N; Nielsen, S; Mizoguchi, K; Ferri, F; Cocco, M; Shimamoto, T

    2011-03-24

    The determination of rock friction at seismic slip rates (about 1 m s(-1)) is of paramount importance in earthquake mechanics, as fault friction controls the stress drop, the mechanical work and the frictional heat generated during slip. Given the difficulty in determining friction by seismological methods, elucidating constraints are derived from experimental studies. Here we review a large set of published and unpublished experiments (∼300) performed in rotary shear apparatus at slip rates of 0.1-2.6 m s(-1). The experiments indicate a significant decrease in friction (of up to one order of magnitude), which we term fault lubrication, both for cohesive (silicate-built, quartz-built and carbonate-built) rocks and non-cohesive rocks (clay-rich, anhydrite, gypsum and dolomite gouges) typical of crustal seismogenic sources. The available mechanical work and the associated temperature rise in the slipping zone trigger a number of physicochemical processes (gelification, decarbonation and dehydration reactions, melting and so on) whose products are responsible for fault lubrication. The similarity between (1) experimental and natural fault products and (2) mechanical work measures resulting from these laboratory experiments and seismological estimates suggests that it is reasonable to extrapolate experimental data to conditions typical of earthquake nucleation depths (7-15 km). It seems that faults are lubricated during earthquakes, irrespective of the fault rock composition and of the specific weakening mechanism involved.

  14. Vipava fault (Slovenia

    Directory of Open Access Journals (Sweden)

    Ladislav Placer

    2008-06-01

    Full Text Available During mapping of the already accomplished Razdrto – Senožeče section of motorway and geologic surveying of construction operations of the trunk road between Razdrto and Vipava in northwestern part of External Dinarides on the southwestern slope of Mt. Nanos, called Rebrnice, a steep NW-SE striking fault was recognized, situated between the Predjama and the Ra{a faults. The fault was named Vipava fault after the Vipava town. An analysis of subrecent gravitational slips at Rebrnice indicates that they were probably associated with the activity of this fault. Unpublished results of a repeated levelling line along the regional road passing across the Vipava fault zone suggest its possible present activity. It would be meaningful to verify this by appropriate geodetic measurements, and to study the actual gravitational slips at Rebrnice. The association between tectonics and gravitational slips in this and in similar extreme cases in the areas of Alps and Dinarides points at the need of complex studying of geologic proceses.

  15. Exploring online evolution of network stacks

    OpenAIRE

    Imai, Pierre

    2013-01-01

    Network stacks today follow a one-size-fits-all philosophy. They are mostly kept unmodified due to often prohibitive costs of engineering, deploying and administrating customisation of the networking software, with the Internet stack architecture still largely being based on designs and assumptions made for the ARPANET 40 years ago. We venture that heterogeneous and rapidly changing networks of the future require, in order to be successful, run-time self-adaptation mechanisms at different tim...

  16. A Time-predictable Stack Cache

    DEFF Research Database (Denmark)

    Abbaspour, Sahar; Brandner, Florian; Schoeberl, Martin

    2013-01-01

    Real-time systems need time-predictable architectures to support static worst-case execution time (WCET) analysis. One architectural feature, the data cache, is hard to analyze when different data areas (e.g., heap allocated and stack allocated data) share the same cache. This sharing leads to le...... of a cache for stack allocated data. Our port of the LLVM C++ compiler supports the management of the stack cache. The combination of stack cache instructions and the hardware implementation of the stack cache is a further step towards timepredictable architectures.......Real-time systems need time-predictable architectures to support static worst-case execution time (WCET) analysis. One architectural feature, the data cache, is hard to analyze when different data areas (e.g., heap allocated and stack allocated data) share the same cache. This sharing leads to less...... precise results of the cache analysis part of the WCET analysis. Splitting the data cache for different data areas enables composable data cache analysis. The WCET analysis tool can analyze the accesses to these different data areas independently. In this paper we present the design and implementation...

  17. StackGAN++: Realistic Image Synthesis with Stacked Generative Adversarial Networks

    OpenAIRE

    Zhang, Han; Xu, Tao; Li, Hongsheng; Zhang, Shaoting; Wang, Xiaogang; Huang, Xiaolei; Metaxas, Dimitris

    2017-01-01

    Although Generative Adversarial Networks (GANs) have shown remarkable success in various tasks, they still face challenges in generating high quality images. In this paper, we propose Stacked Generative Adversarial Networks (StackGAN) aiming at generating high-resolution photo-realistic images. First, we propose a two-stage generative adversarial network architecture, StackGAN-v1, for text-to-image synthesis. The Stage-I GAN sketches the primitive shape and colors of the object based on given...

  18. Fault morphology of the lyo Fault, the Median Tectonic Line Active Fault System

    OpenAIRE

    後藤, 秀昭

    1996-01-01

    In this paper, we investigated the various fault features of the lyo fault and depicted fault lines or detailed topographic map. The results of this paper are summarized as follows; 1) Distinct evidence of the right-lateral movement is continuously discernible along the lyo fault. 2) Active fault traces are remarkably linear suggesting that the angle of fault plane is high. 3) The lyo fault can be divided into four segments by jogs between left-stepping traces. 4) The mean slip rate is 1.3 ~ ...

  19. Relative role of transfer zones in controlling sequence stacking patterns and facies distribution: insights from the Fushan Depression, South China Sea

    Science.gov (United States)

    Liu, Entao; Wang, Hua; Li, Yuan; Huang, Chuanyan

    2015-04-01

    In sedimentary basins, a transfer zone can be defined as a coordinated system of deformational features which has good prospects for hydrocarbon exploration. Although the term 'transfer zone' has been widely applied to the study of extensional basins, little attention has been paid to its controlling effect on sequence tracking pattern and depositional facies distribution. Fushan Depression is a half-graben rift sub-basin, located in the southeast of the Beibuwan Basin, South China Sea. In this study, comparative analysis of seismic reflection, palaeogeomorphology, fault activity and depositional facies distribution in the southern slope indicates that three different types of sequence stacking patterns (i.e. multi-level step-fault belt in the western area, flexure slope belt in the central area, gentle slope belt in the eastern area) were developed along the southern slope, together with a large-scale transfer zone in the central area, at the intersection of the western and eastern fault systems. Further analysis shows that the transfer zone played an important role in the diversity of sequence stacking patterns in the southern slope by dividing the Fushan Depression into two non-interfering tectonic systems forming different sequence patterns, and leading to the formation of the flexure slope belt in the central area. The transfer zone had an important controlling effect on not only the diversity of sequence tracking patterns, but also the facies distribution on the relay ramp. During the high-stand stage, under the controlling effect of the transfer zone, the sediments contain a significant proportion of coarser material accumulated and distributed along the ramp axis. By contrast, during the low-stand stage, the transfer zone did not seem to contribute significantly to the low-stand fan distribution which was mainly controlled by the slope gradient (palaeogeomorphology). Therefore, analysis of the transfer zone can provide a new perspective for basin analysis

  20. Development of an automatic subsea blowout preventer stack control system using PLC based SCADA.

    Science.gov (United States)

    Cai, Baoping; Liu, Yonghong; Liu, Zengkai; Wang, Fei; Tian, Xiaojie; Zhang, Yanzhen

    2012-01-01

    An extremely reliable remote control system for subsea blowout preventer stack is developed based on the off-the-shelf triple modular redundancy system. To meet a high reliability requirement, various redundancy techniques such as controller redundancy, bus redundancy and network redundancy are used to design the system hardware architecture. The control logic, human-machine interface graphical design and redundant databases are developed by using the off-the-shelf software. A series of experiments were performed in laboratory to test the subsea blowout preventer stack control system. The results showed that the tested subsea blowout preventer functions could be executed successfully. For the faults of programmable logic controllers, discrete input groups and analog input groups, the control system could give correct alarms in the human-machine interface. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.

  1. Surface growth mechanisms and structural faulting in the growth of large single and spherulitic titanosilicate ETS-4 crystals

    Science.gov (United States)

    Miraglia, Peter Q.; Yilmaz, Bilge; Warzywoda, Juliusz; Sacco, Albert

    2004-10-01

    Morphological, surface and crystallographic analyses of titanosilicate ETS-4 products, with diverse habits ranging from spherulitic particles composed of submicron crystallites to large single crystals, are presented. Pole figures revealed that crystal surfaces with a-, b- and c- axes corresponded to , and directions, respectively. Thus, technologically important 8-membered ring pores and titania chains in ETS-4 run along the b-axis of single crystals and terminate at the smallest crystal face. Height of the spiral growth steps observed on {1 0 0} and {0 0 1} surfaces corresponded to the interplanar spacings associated with their crystallographic orientation, and is equivalent to the thickness of building units that form the ETS-4 framework. Data suggest that the more viscous synthesis mixtures, with a large driving force for growth, increased the two- and three-dimensional nucleation, while limiting the transport of nutrients to the growth surface. These conditions increase the tendency for stacking fault formation on {1 0 0} surfaces and small angle branching, which eventually results in spherulitic growth. The growth of high quality ETS-4 single crystals (from less viscous synthesis mixtures) occurred at lower surface nucleation rates. Data suggest that these high quality, large crystals grew due to one-dimensional nucleation at spiral hillocks, and indicate that under these conditions un-faulted growth is preferred.

  2. Computer simulation of void formation in residual gas atom free metals by dual beam irradiation experiments

    International Nuclear Information System (INIS)

    Shimomura, Y.; Nishiguchi, R.; La Rubia, T.D. de; Guinan, M.W.

    1992-01-01

    In our recent experiments (1), we found that voids nucleate at vacancy clusters which trap gas atoms such as hydrogen and helium in ion- and neutron-irradiated copper. A molecular dynamics computer simulation, which implements an empirical embedded atom method to calculate forces that act on atoms in metals, suggests that a void nucleation occurs in pure copper at six and seven vacancy clusters. The structure of six and seven vacancy clusters in copper fluctuates between a stacking fault tetrahedron and a void. When a hydrogen is trapped at voids of six and seven vacancy, a void can keep their structure for appreciably long time; that is, the void do not relax to a stacking fault tetrahedron and grows to a large void. In order to explore the detailed atomics of void formation, it is emphasized that dual-beam irradiation experiments that utilize beams of gas atoms and self-ions should be carried out with residual gas atom free metal specimens. (author)

  3. The effect of nitrogen on martensite formation in a Cr-Mn-Ni stainless steel

    International Nuclear Information System (INIS)

    Biggs, T.; Knutsen, R.D.

    1995-01-01

    The influence of nitrogen (0 to 0.27 wt%) on martensite formation in an experimental low-nickel stainless-steel alloy (Fe-17Cr-7Mn-4Ni) has been investigated. The alloys containing 0.1 wt% or more nitrogen are fully austenitic at room temperature; those containing less nitrogen consist of a mixture of austenite, martensite and δ-ferrite. The alloys containing less than 0.2 wt% nitrogen are metastable and undergo a transformation from austenite to martensite on deformation. Transmission electron microscopy investigations suggest that, within the nitrogen range considered in this investigation, the addition of nitrogen causes an increase in stacking fault energy which in turn inhibits the nucleation of martensite. As the low-nitrogen alloys (less than 0.2 wt% nitrogen) undergo deformation, ε-martensite (with the [ anti 110] γ and [ anti 12 anti 10] ε zone axes parallel) is observed at the intersection of stacking faults. With increasing strain, the presence of α'-martensite is observed in conjunction with the ε-martensite, and only α'-martensite is observed at very high strains. Both the Nishiyama-Wasserman and Kurdjumov-Sachs orientation relationships are observed between austenite and α'-martensite. The transformation to martensite during deformation causes a significant variation in room-temperature mechanical properties, despite the overall narrow range in composition considered. (orig.)

  4. Active Fault Isolation in MIMO Systems

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2014-01-01

    isolation is based directly on the input/output s ignals applied for the fault detection. It is guaranteed that the fault group includes the fault that had occurred in the system. The second step is individual fault isolation in the fault group . Both types of isolation are obtained by applying dedicated......Active fault isolation of parametric faults in closed-loop MIMO system s are considered in this paper. The fault isolation consists of two steps. T he first step is group- wise fault isolation. Here, a group of faults is isolated from other pos sible faults in the system. The group-wise fault...

  5. Start-Stop Test Procedures on the PEMFC Stack Level

    DEFF Research Database (Denmark)

    Mitzel, Jens; Nygaard, Frederik; Veltzé, Sune

    The test is addressed to investigate the influence on stack durability of a long stop followed by a restart of a stack. Long stop should be defined as a stop in which the anodic compartment is fully filled by air due to stack leakages. In systems, leakage level of the stack is low and time to fil...

  6. Principles for Instructional Stack Development in HyperCard.

    Science.gov (United States)

    McEneaney, John E.

    The purpose of this paper is to provide information about obtaining and using HyperCard stacks that introduce users to principles of stack development. The HyperCard stacks described are available for downloading free of charge from a server at Indiana University South Bend. Specific directions are given for stack use, with advice for beginners. A…

  7. Resistivity Structures of the Chelungpu Fault in the Taichung Area, Taiwan

    Directory of Open Access Journals (Sweden)

    Ping-Hu Cheng

    2006-01-01

    Full Text Available We conducted magnetotelluric prospecting in the Taichung area to investigate subsurface resistivity structures of the Chelungpu fault and the resistivity of rock formations. The results indicate that the Chelungpu fault is a complex fault system consisting of two major fault zones, several fracture zones, and back thrust. The two major fault zones, the basal and the Chi-Chi fault zone are about 800 m apart on the ground and converge to a narrow band at a depth of 3000 m. The fault zones are not smooth, composed of ramps and platforms with an average eastward dipping angle of 35° - 37° within the depth of 3000 m. In the shallower region, the basal fault zone has developed along the boundary of the Toukoshan Formation (resistivity: 200 - 400 Ω-m at the footwall and the Neogene formations on the hanging wall, where the Cholan Formation, the Chinshiu Shale, and the Kueichulai Formation have respective resistivity mainly in the ranges: 40 - 100, 8 - 60, and 50 - 150 Ω-m. While the Chi-Chi fault zone has developed along the weak layers of the Cholan Formation where resistivity is lower than the unsheared block.

  8. Fault Detection for Industrial Processes

    Directory of Open Access Journals (Sweden)

    Yingwei Zhang

    2012-01-01

    Full Text Available A new fault-relevant KPCA algorithm is proposed. Then the fault detection approach is proposed based on the fault-relevant KPCA algorithm. The proposed method further decomposes both the KPCA principal space and residual space into two subspaces. Compared with traditional statistical techniques, the fault subspace is separated based on the fault-relevant influence. This method can find fault-relevant principal directions and principal components of systematic subspace and residual subspace for process monitoring. The proposed monitoring approach is applied to Tennessee Eastman process and penicillin fermentation process. The simulation results show the effectiveness of the proposed method.

  9. EmuStack: An OpenStack-Based DTN Network Emulation Platform (Extended Version

    Directory of Open Access Journals (Sweden)

    Haifeng Li

    2016-01-01

    Full Text Available With the advancement of computing and network virtualization technology, the networking research community shows great interest in network emulation. Compared with network simulation, network emulation can provide more relevant and comprehensive details. In this paper, EmuStack, a large-scale real-time emulation platform for Delay Tolerant Network (DTN, is proposed. EmuStack aims at empowering network emulation to become as simple as network simulation. Based on OpenStack, distributed synchronous emulation modules are developed to enable EmuStack to implement synchronous and dynamic, precise, and real-time network emulation. Meanwhile, the lightweight approach of using Docker container technology and network namespaces allows EmuStack to support a (up to hundreds of nodes large-scale topology with only several physical nodes. In addition, EmuStack integrates the Linux Traffic Control (TC tools with OpenStack for managing and emulating the virtual link characteristics which include variable bandwidth, delay, loss, jitter, reordering, and duplication. Finally, experiences with our initial implementation suggest the ability to run and debug experimental network protocol in real time. EmuStack environment would bring qualitative change in network research works.

  10. Fault tree analysis

    International Nuclear Information System (INIS)

    1981-09-01

    Suggestion are made concerning the method of the fault tree analysis, the use of certain symbols in the examination of system failures. This purpose of the fault free analysis is to find logical connections of component or subsystem failures leading to undesirable occurrances. The results of these examinations are part of the system assessment concerning operation and safety. The objectives of the analysis are: systematical identification of all possible failure combinations (causes) leading to a specific undesirable occurrance, finding of reliability parameters such as frequency of failure combinations, frequency of the undesirable occurrance or non-availability of the system when required. The fault tree analysis provides a near and reconstructable documentation of the examination. (orig./HP) [de

  11. Forced Air-Breathing PEMFC Stacks

    Directory of Open Access Journals (Sweden)

    K. S. Dhathathreyan

    2012-01-01

    Full Text Available Air-breathing fuel cells have a great potential as power sources for various electronic devices. They differ from conventional fuel cells in which the cells take up oxygen from ambient air by active or passive methods. The air flow occurs through the channels due to concentration and temperature gradient between the cell and the ambient conditions. However developing a stack is very difficult as the individual cell performance may not be uniform. In order to make such a system more realistic, an open-cathode forced air-breathing stacks were developed by making appropriate channel dimensions for the air flow for uniform performance in a stack. At CFCT-ARCI (Centre for Fuel Cell Technology-ARC International we have developed forced air-breathing fuel cell stacks with varying capacity ranging from 50 watts to 1500 watts. The performance of the stack was analysed based on the air flow, humidity, stability, and so forth, The major advantage of the system is the reduced number of bipolar plates and thereby reduction in volume and weight. However, the thermal management is a challenge due to the non-availability of sufficient air flow to remove the heat from the system during continuous operation. These results will be discussed in this paper.

  12. Levitation characteristics of HTS tape stacks

    Energy Technology Data Exchange (ETDEWEB)

    Pokrovskiy, S. V.; Ermolaev, Y. S.; Rudnev, I. A. [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow (Russian Federation)

    2015-03-15

    Due to the considerable development of the technology of second generation high-temperature superconductors and a significant improvement in their mechanical and transport properties in the last few years it is possible to use HTS tapes in the magnetic levitation systems. The advantages of tapes on a metal substrate as compared with bulk YBCO material primarily in the strength, and the possibility of optimizing the convenience of manufacturing elements of levitation systems. In the present report presents the results of the magnetic levitation force measurements between the stack of HTS tapes containing of tapes and NdFeB permanent magnet in the FC and ZFC regimes. It was found a non- linear dependence of the levitation force from the height of the array of stack in both modes: linear growth at small thickness gives way to flattening and constant at large number of tapes in the stack. Established that the levitation force of stacks comparable to that of bulk samples. The numerical calculations using finite element method showed that without the screening of the applied field the levitation force of the bulk superconductor and the layered superconductor stack with a critical current of tapes increased by the filling factor is exactly the same, and taking into account the screening force slightly different.

  13. Heterogeneity in the Fault Damage Zone: a Field Study on the Borrego Fault, B.C., Mexico

    Science.gov (United States)

    Ostermeijer, G.; Mitchell, T. M.; Dorsey, M. T.; Browning, J.; Rockwell, T. K.; Aben, F. M.; Fletcher, J. M.; Brantut, N.

    2017-12-01

    The nature and distribution of damage around faults, and its impacts on fault zone properties has been a hot topic of research over the past decade. Understanding the mechanisms that control the formation of off fault damage can shed light on the processes during the seismic cycle, and the nature of fault zone development. Recent published work has identified three broad zones of damage around most faults based on the type, intensity, and extent of fracturing; Tip, Wall, and Linking damage. Although these zones are able to adequately characterise the general distribution of damage, little has been done to identify the nature of damage heterogeneity within those zones, often simplifying the distribution to fit log-normal linear decay trends. Here, we attempt to characterise the distribution of fractures that make up the wall damage around seismogenic faults. To do so, we investigate an extensive two dimensional fracture network exposed on a river cut platform along the Borrego Fault, BC, Mexico, 5m wide, and extending 20m from the fault core into the damage zone. High resolution fracture mapping of the outcrop, covering scales ranging three orders of magnitude (cm to m), has allowed for detailed observations of the 2D damage distribution within the fault damage zone. Damage profiles were obtained along several 1D transects perpendicular to the fault and micro-damage was examined from thin-sections at various locations around the outcrop for comparison. Analysis of the resulting fracture network indicates heterogeneities in damage intensity at decimetre scales resulting from a patchy distribution of high and low intensity corridors and clusters. Such patchiness may contribute to inconsistencies in damage zone widths defined along 1D transects and the observed variability of fracture densities around decay trends. How this distribution develops with fault maturity and the scaling of heterogeneities above and below the observed range will likely play a key role in

  14. Computer hardware fault administration

    Science.gov (United States)

    Archer, Charles J.; Megerian, Mark G.; Ratterman, Joseph D.; Smith, Brian E.

    2010-09-14

    Computer hardware fault administration carried out in a parallel computer, where the parallel computer includes a plurality of compute nodes. The compute nodes are coupled for data communications by at least two independent data communications networks, where each data communications network includes data communications links connected to the compute nodes. Typical embodiments carry out hardware fault administration by identifying a location of a defective link in the first data communications network of the parallel computer and routing communications data around the defective link through the second data communications network of the parallel computer.

  15. Fault Tolerant Computer Architecture

    CERN Document Server

    Sorin, Daniel

    2009-01-01

    For many years, most computer architects have pursued one primary goal: performance. Architects have translated the ever-increasing abundance of ever-faster transistors provided by Moore's law into remarkable increases in performance. Recently, however, the bounty provided by Moore's law has been accompanied by several challenges that have arisen as devices have become smaller, including a decrease in dependability due to physical faults. In this book, we focus on the dependability challenge and the fault tolerance solutions that architects are developing to overcome it. The two main purposes

  16. Fault tolerant linear actuator

    Science.gov (United States)

    Tesar, Delbert

    2004-09-14

    In varying embodiments, the fault tolerant linear actuator of the present invention is a new and improved linear actuator with fault tolerance and positional control that may incorporate velocity summing, force summing, or a combination of the two. In one embodiment, the invention offers a velocity summing arrangement with a differential gear between two prime movers driving a cage, which then drives a linear spindle screw transmission. Other embodiments feature two prime movers driving separate linear spindle screw transmissions, one internal and one external, in a totally concentric and compact integrated module.

  17. Summary and conclusions of the faults-in-clay project

    International Nuclear Information System (INIS)

    Hallam, J.R.; Brightman, M.A.; Jackson, P.D.; Sen, M.A.

    1992-01-01

    This report summarises a research project carried out by the British Geological Survey, in cooperation with ISMES of Italy, into the geophysical detection of faults in clay formations and the determination of the hydrogeological effects of such faults on the groundwater flow regime. Following evaluation of potential research sites, an extensive programme of investigations was conducted at Down Ampney, Gloucester, where the Oxford Clay formation is underlain by the aquifers of the Great Oolite Limestone group. A previously unknown fault of 50 m throw was identified and delineated by electrical resistivity profiling; the subsequent development of a technique utilising measurements of total resistance improved the resolution of the fault 'location' to an accuracy of better than one metre. Marked anisotropy of the clay resistivities complicates conventional geophysical interpretation, but gives rise to a characteristic anomaly across the steeply inclined strata in the fault zone. After exploratory core drilling, an array of 13 boreholes was designed and completed for cross-hole seismic tomography and hydrogeological measurement and testing. The groundwater heads in the clays were found to be in disequilibrium with those in the aquifers, as a result of water supply abstraction. The indication is that the hydraulic conductivity of the fault zone is higher than that of the surrounding clay by between one and two orders of magnitude. Methodologies for the general investigation of faults in clay are discussed. (Author)

  18. Wind turbine fault detection and fault tolerant control

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Johnson, Kathryn

    2013-01-01

    In this updated edition of a previous wind turbine fault detection and fault tolerant control challenge, we present a more sophisticated wind turbine model and updated fault scenarios to enhance the realism of the challenge and therefore the value of the solutions. This paper describes...

  19. Progress of MCFC stack technology at Toshiba

    Energy Technology Data Exchange (ETDEWEB)

    Hori, M.; Hayashi, T.; Shimizu, Y. [Toshiba Corp., Tokyo (Japan)

    1996-12-31

    Toshiba is working on the development of MCFC stack technology; improvement of cell characteristics, and establishment of separator technology. For the cell technology, Toshiba has concentrated on both the restraints of NiO cathode dissolution and electrolyte loss from cells, which are the critical issues to extend cell life in MCFC, and great progress has been made. On the other hand, recognizing that the separator is one of key elements in accomplishing reliable and cost-competitive MCFC stacks, Toshiba has been accelerating the technology establishment and verification of an advanced type separator. A sub-scale stack with such a separator was provided for an electric generating test, and has been operated for more than 10,000 hours. This paper presents several topics obtained through the technical activities in the MCFC field at Toshiba.

  20. Development of an Integrated Polymer Microfluidic Stack

    International Nuclear Information System (INIS)

    Datta, Proyag; Hammacher, Jens; Pease, Mark; Gurung, Sitanshu; Goettert, Jost

    2006-01-01

    Microfluidic is a field of considerable interest. While significant research has been carried out to develop microfluidic components, very little has been done to integrate the components into a complete working system. We present a flexible modular system platform that addresses the requirements of a complete microfluidic system. A microfluidic stack system is demonstrated with the layers of the stack being modular for specific functions. The stack and accompanying infrastructure provides an attractive platform for users to transition their design concepts into a working microfluidic system quickly with very little effort. The concept is demonstrated by using the system to carry out a chemilumiscence experiment. Details regarding the fabrication, assembly and experimental methods are presented

  1. Detailed Electrochemical Characterisation of Large SOFC Stacks

    DEFF Research Database (Denmark)

    Mosbæk, Rasmus Rode; Hjelm, Johan; Barfod, R.

    2012-01-01

    application of advanced methods for detailed electrochemical characterisation during operation. An operating stack is subject to steep compositional gradients in the gaseous reactant streams, and significant temperature gradients across each cell and across the stack, which makes it a complex system...... Fuel Cell A/S was characterised in detail using electrochemical impedance spectroscopy. An investigation of the optimal geometrical placement of the current probes and voltage probes was carried out in order to minimise measurement errors caused by stray impedances. Unwanted stray impedances...... are particularly problematic at high frequencies. Stray impedances may be caused by mutual inductance and stray capacitance in the geometrical set-up and do not describe the fuel cell. Three different stack geometries were investigated by electrochemical impedance spectroscopy. Impedance measurements were carried...

  2. High power, repetitive stacked Blumlein pulse generators

    Energy Technology Data Exchange (ETDEWEB)

    Davanloo, F; Borovina, D L; Korioth, J L; Krause, R K; Collins, C B [Univ. of Texas at Dallas, Richardson, TX (United States). Center for Quantum Electronics; Agee, F J [US Air Force Phillips Lab., Kirtland AFB, NM (United States); Kingsley, L E [US Army CECOM, Ft. Monmouth, NJ (United States)

    1997-12-31

    The repetitive stacked Blumlein pulse power generators developed at the University of Texas at Dallas consist of several triaxial Blumleins stacked in series at one end. The lines are charged in parallel and synchronously commuted with a single switch at the other end. In this way, relatively low charging voltages are multiplied to give a high discharge voltage across an arbitrary load. Extensive characterization of these novel pulsers have been performed over the past few years. Results indicate that they are capable of producing high power waveforms with rise times and repetition rates in the range of 0.5-50 ns and 1-300 Hz, respectively, using a conventional thyratron, spark gap, or photoconductive switch. The progress in the development and use of stacked Blumlein pulse generators is reviewed. The technology and the characteristics of these novel pulsers driving flash x-ray diodes are discussed. (author). 4 figs., 5 refs.

  3. Calculation of tritium release from reactor's stack

    International Nuclear Information System (INIS)

    Akhadi, M.

    1996-01-01

    Method for calculation of tritium release from nuclear to environment has been discussed. Part of gas effluent contain tritium in form of HTO vapor released from reactor's stack was sampled using silica-gel. The silica-gel was put in the water to withdraw HTO vapor absorbed by silica-gel. Tritium concentration in the water was measured by liquid scintillation counter of Aloka LSC-703. Tritium concentration in the gas effluent and total release of tritium from reactor's stack during certain interval time were calculated using simple mathematic formula. This method has examined for calculation of tritium release from JRR-3M's stack of JAERI, Japan. From the calculation it was obtained the value of tritium release as much as 4.63 x 10 11 Bq during one month. (author)

  4. Faults in clays their detection and properties

    International Nuclear Information System (INIS)

    Baldi, G.; Carabelli, E.; Chiantore, V.; Colombo, P.F.; Gruszka, A.; Pensieri, R.; Superbo, S.; Gera, F.

    1991-01-01

    The 'Faults in clays project', a cooperative research effort between Ismes and Enea of Italy and BGS and Exeter University of the UK, has been aimed at assessing and improving the resolution capability of some high resolution geophysical techniques for the detection of discontinuities in clay formations. All Ismes activities have been carried out in Italy: they consisted in the search of one or more sites - faulted clay formations - suitable for the execution of geophysical and geotechnical investigations, in the execution of such tests and in additional geological surveys and laboratory (geotechnical and geochemical) testing. The selected sites were two quarries in plio-pleistocenic clay formations in central Italy where faults had been observed. The greatest part of the research work has been carried out in the Orte site where also two 90 m boreholes have been drilled and cored. Geophysical work at Orte consisted of vertical electrical soundings (VESs) and horizontal electrical lines (HELs), four high resolution seismic reflection lines, and in-hole and cross-hole logs. Laboratory activities were geotechnical characterization and permeability tests, and measurements of disequilibrium in the uranium decay series. At Narni, where Exeter University sampled soil gases for geochemical analyses, the geophysical work consisted in a geo-electrical survey (five VESs and two HELs), and in two high resolution reflection seismic lines. Additional investigations included a structural geology survey. The main conclusion of the research is that current geophysical techniques do not have a resolution capacity sufficient to detect the existence and determine the characteristics of faults in deep homogeneous clay formations

  5. Radio-frequency properties of stacked long Josephson junctions with nonuniform bias current distribution

    DEFF Research Database (Denmark)

    Filatrella, G; Pedersen, Niels Falsig

    1999-01-01

    We have numerically investigated the behavior of stacks of long Josephson junctions considering a nonuniform bias profile. In the presence of a microwave field the nonuniform bias, which favors the formation of fluxons, can give rise to a change of the sequence of radio-frequency induced steps...

  6. Fault management and systems knowledge

    Science.gov (United States)

    2016-12-01

    Pilots are asked to manage faults during flight operations. This leads to the training question of the type and depth of system knowledge required to respond to these faults. Based on discussions with multiple airline operators, there is agreement th...

  7. ESR dating of fault rocks

    International Nuclear Information System (INIS)

    Lee, Hee Kwon

    2002-03-01

    Past movement on faults can be dated by measurement of the intensity of ESR signals in quartz. These signals are reset by local lattice deformation and local frictional heating on grain contacts at the time of fault movement. The ESR signals then trow back as a result of bombardment by ionizing radiation from surrounding rocks. The age is obtained from the ratio of the equivalent dose, needed to produce the observed signal, to the dose rate. Fine grains are more completely reset during faulting, and a plot of age vs grain size shows a plateau for grains below critical size : these grains are presumed to have been completely zeroed by the last fault activity. We carried out ESR dating of fault rocks collected from the Yangsan fault system. ESR dates from the this fault system range from 870 to 240 ka. Results of this research suggest that long-term cyclic fault activity continued into the pleistocene

  8. Fault diagnosis of induction motors

    CERN Document Server

    Faiz, Jawad; Joksimović, Gojko

    2017-01-01

    This book is a comprehensive, structural approach to fault diagnosis strategy. The different fault types, signal processing techniques, and loss characterisation are addressed in the book. This is essential reading for work with induction motors for transportation and energy.

  9. ESR dating of fault rocks

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hee Kwon [Kangwon National Univ., Chuncheon (Korea, Republic of)

    2002-03-15

    Past movement on faults can be dated by measurement of the intensity of ESR signals in quartz. These signals are reset by local lattice deformation and local frictional heating on grain contacts at the time of fault movement. The ESR signals then trow back as a result of bombardment by ionizing radiation from surrounding rocks. The age is obtained from the ratio of the equivalent dose, needed to produce the observed signal, to the dose rate. Fine grains are more completely reset during faulting, and a plot of age vs grain size shows a plateau for grains below critical size : these grains are presumed to have been completely zeroed by the last fault activity. We carried out ESR dating of fault rocks collected from the Yangsan fault system. ESR dates from the this fault system range from 870 to 240 ka. Results of this research suggest that long-term cyclic fault activity continued into the pleistocene.

  10. Fault zone architecture of a major oblique-slip fault in the Rawil depression, Western Helvetic nappes, Switzerland

    Science.gov (United States)

    Gasser, D.; Mancktelow, N. S.

    2009-04-01

    The Helvetic nappes in the Swiss Alps form a classic fold-and-thrust belt related to overall NNW-directed transport. In western Switzerland, the plunge of nappe fold axes and the regional distribution of units define a broad depression, the Rawil depression, between the culminations of Aiguilles Rouge massif to the SW and Aar massif to the NE. A compilation of data from the literature establishes that, in addition to thrusts related to nappe stacking, the Rawil depression is cross-cut by four sets of brittle faults: (1) SW-NE striking normal faults that strike parallel to the regional fold axis trend, (2) NW-SE striking normal faults and joints that strike perpendicular to the regional fold axis trend, and (3) WNW-ESE striking normal plus dextral oblique-slip faults as well as (4) WSW-ENE striking normal plus dextral oblique-slip faults that both strike oblique to the regional fold axis trend. We studied in detail a beautifully exposed fault from set 3, the Rezli fault zone (RFZ) in the central Wildhorn nappe. The RFZ is a shallow to moderately-dipping (ca. 30-60˚) fault zone with an oblique-slip displacement vector, combining both dextral and normal components. It must have formed in approximately this orientation, because the local orientation of fold axes corresponds to the regional one, as does the generally vertical orientation of extensional joints and veins associated with the regional fault set 2. The fault zone crosscuts four different lithologies: limestone, intercalated marl and limestone, marl and sandstone, and it has a maximum horizontal dextral offset component of ~300 m and a maximum vertical normal offset component of ~200 m. Its internal architecture strongly depends on the lithology in which it developed. In the limestone, it consists of veins, stylolites, cataclasites and cemented gouge, in the intercalated marls and limestones of anastomosing shear zones, brittle fractures, veins and folds, in the marls of anastomosing shear zones, pressure

  11. Sedimentary environments and stratigraphy of the carbonate-silicilastic deposits of the Shirgesht Formation: implications for eustasy and local tectonism in the Kalmard Block, Central Iran

    Directory of Open Access Journals (Sweden)

    aram bayetgoll

    2015-10-01

    Full Text Available Introduction   Sedimentological and sequence stratigraphic analysis providing insight into the main relationships between sequence architecture and stacking pattern, syn/post-depositional tectonics, and eustatic sea-level fluctuations (Gawthorpe and Leeder 2000; Zecchin et al. 2003, 2004; Carpentier et al. 2007. Relative variations in sea level are due to tectonic activity and eustasy. The Shirgesht Formation in the Kalmard Block of Central Iran provides a useful case study for to determine the processes responsible on internal architecture and stacking pattern of depositional sequences in a half-graben basin. In the Shirgesht Formation, siliciclastic and carbonate successions of the Kalmard Basin, the cyclic stratigraphic record is the result of the complex interaction of regional uplift, eustasy, local tectonics, sediment supply, and sedimentary processes (Bayet-Goll 2009, 2014; Hosseini-Barzi and Bayet-Goll 2009.     Material & Methods   Lower Paleozoic successions in Tabas and Kalmard blocks from Central Iran share the faunal and floral characteristics with other Gondwana sectors such as south-western Europe and north Africa–Middle East (Ghaderi et al. 2009. The geology of these areas was outlined by Ruttner et al. (1968 and by Bruton et al. (2004. The Cambrian-Middle Triassic strata in the Kalmard Block were deposited in a shallow water platform that possesses lithologic dissimilarities with the Tabas area (Aghanabati 2004. The occurrence of two active faults indicates clearly that Kalmard basin formed a mobile zone throughout the Paleozoic so that lithostratigraphic units show considerably contrasting facies in comparison with Tabas basin (Hosseini-Barzi and Bayet-Goll 2009; Bayet-Goll 2014 . The Shirgesht Formation in the Block Kalmard is mainly composed of carbonate-siliciclastic successions that disconformability overlain Kalmard Formation (attributed to Pre-Cambrian and is underlain by Gachal (Carboniferous or Rahdar (Devonian

  12. Can diligent and extensive mapping of faults provide reliable estimates of the expected maximum earthquakes at these faults? No. (Invited)

    Science.gov (United States)

    Bird, P.

    2010-12-01

    The hope expressed in the title question above can be contradicted in 5 ways, listed below. To summarize, an earthquake rupture can be larger than anticipated either because the fault system has not been fully mapped, or because the rupture is not limited to the pre-existing fault network. 1. Geologic mapping of faults is always incomplete due to four limitations: (a) Map-scale limitation: Faults below a certain (scale-dependent) apparent offset are omitted; (b) Field-time limitation: The most obvious fault(s) get(s) the most attention; (c) Outcrop limitation: You can't map what you can't see; and (d) Lithologic-contrast limitation: Intra-formation faults can be tough to map, so they are often assumed to be minor and omitted. If mapping is incomplete, fault traces may be longer and/or better-connected than we realize. 2. Fault trace “lengths” are unreliable guides to maximum magnitude. Fault networks have multiply-branching, quasi-fractal shapes, so fault “length” may be meaningless. Naming conventions for main strands are unclear, and rarely reviewed. Gaps due to Quaternary alluvial cover may not reflect deeper seismogenic structure. Mapped kinks and other “segment boundary asperities” may be only shallow structures. Also, some recent earthquakes have jumped and linked “separate” faults (Landers, California 1992; Denali, Alaska, 2002) [Wesnousky, 2006; Black, 2008]. 3. Distributed faulting (“eventually occurring everywhere”) is predicted by several simple theories: (a) Viscoelastic stress redistribution in plate/microplate interiors concentrates deviatoric stress upward until they fail by faulting; (b) Unstable triple-junctions (e.g., between 3 strike-slip faults) in 2-D plate theory require new faults to form; and (c) Faults which appear to end (on a geologic map) imply distributed permanent deformation. This means that all fault networks evolve and that even a perfect fault map would be incomplete for future ruptures. 4. A recent attempt

  13. Fluid flow and permeabilities in basement fault zones

    Science.gov (United States)

    Hollinsworth, Allan; Koehn, Daniel

    2017-04-01

    rocks, and younger Mesozoic age faults may provide analogues for the West Shetland basin. Samples have been collected from both of these localities, and will be examined by optical and scanning electron microscopy. X-Ray micro-tomography will also be used to analyse the permeability characteristics of the fault rocks. Our understanding of fault zone permeability is crucial for a number of research areas, including earthquake geoscience, economic mineral formation, and hydrocarbon systems. As a result, this research has relevance to a variety of industry sectors, including oil and gas (and ccs), nuclear waste disposal, geothermal and mining.

  14. Nonlinearly stacked low noise turbofan stator

    Science.gov (United States)

    Schuster, William B. (Inventor); Nolcheff, Nick A. (Inventor); Gunaraj, John A. (Inventor); Kontos, Karen B. (Inventor); Weir, Donald S. (Inventor)

    2009-01-01

    A nonlinearly stacked low noise turbofan stator vane having a characteristic curve that is characterized by a nonlinear sweep and a nonlinear lean is provided. The stator is in an axial fan or compressor turbomachinery stage that is comprised of a collection of vanes whose highly three-dimensional shape is selected to reduce rotor-stator and rotor-strut interaction noise while maintaining the aerodynamic and mechanical performance of the vane. The nonlinearly stacked low noise turbofan stator vane reduces noise associated with the fan stage of turbomachinery to improve environmental compatibility.

  15. Introduction to fault tree analysis

    International Nuclear Information System (INIS)

    Barlow, R.E.; Lambert, H.E.

    1975-01-01

    An elementary, engineering oriented introduction to fault tree analysis is presented. The basic concepts, techniques and applications of fault tree analysis, FTA, are described. The two major steps of FTA are identified as (1) the construction of the fault tree and (2) its evaluation. The evaluation of the fault tree can be qualitative or quantitative depending upon the scope, extensiveness and use of the analysis. The advantages, limitations and usefulness of FTA are discussed

  16. Fault Tolerant Wind Farm Control

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob

    2013-01-01

    In the recent years the wind turbine industry has focused on optimizing the cost of energy. One of the important factors in this is to increase reliability of the wind turbines. Advanced fault detection, isolation and accommodation are important tools in this process. Clearly most faults are deal...... scenarios. This benchmark model is used in an international competition dealing with Wind Farm fault detection and isolation and fault tolerant control....

  17. Row fault detection system

    Science.gov (United States)

    Archer, Charles Jens [Rochester, MN; Pinnow, Kurt Walter [Rochester, MN; Ratterman, Joseph D [Rochester, MN; Smith, Brian Edward [Rochester, MN

    2008-10-14

    An apparatus, program product and method checks for nodal faults in a row of nodes by causing each node in the row to concurrently communicate with its adjacent neighbor nodes in the row. The communications are analyzed to determine a presence of a faulty node or connection.

  18. Fault isolation techniques

    Science.gov (United States)

    Dumas, A.

    1981-01-01

    Three major areas that are considered in the development of an overall maintenance scheme of computer equipment are described. The areas of concern related to fault isolation techniques are: the programmer (or user), company and its policies, and the manufacturer of the equipment.

  19. Fault Tolerant Control Systems

    DEFF Research Database (Denmark)

    Bøgh, S. A.

    This thesis considered the development of fault tolerant control systems. The focus was on the category of automated processes that do not necessarily comprise a high number of identical sensors and actuators to maintain safe operation, but still have a potential for improving immunity to component...

  20. Fault-Related Sanctuaries

    Science.gov (United States)

    Piccardi, L.

    2001-12-01

    Beyond the study of historical surface faulting events, this work investigates the possibility, in specific cases, of identifying pre-historical events whose memory survives in myths and legends. The myths of many famous sacred places of the ancient world contain relevant telluric references: "sacred" earthquakes, openings to the Underworld and/or chthonic dragons. Given the strong correspondence with local geological evidence, these myths may be considered as describing natural phenomena. It has been possible in this way to shed light on the geologic origin of famous myths (Piccardi, 1999, 2000 and 2001). Interdisciplinary researches reveal that the origin of several ancient sanctuaries may be linked in particular to peculiar geological phenomena observed on local active faults (like ground shaking and coseismic surface ruptures, gas and flames emissions, strong underground rumours). In many of these sanctuaries the sacred area is laid directly above the active fault. In a few cases, faulting has affected also the archaeological relics, right through the main temple (e.g. Delphi, Cnidus, Hierapolis of Phrygia). As such, the arrangement of the cult site and content of relative myths suggest that specific points along the trace of active faults have been noticed in the past and worshiped as special `sacred' places, most likely interpreted as Hades' Doors. The mythological stratification of most of these sanctuaries dates back to prehistory, and points to a common derivation from the cult of the Mother Goddess (the Lady of the Doors), which was largely widespread since at least 25000 BC. The cult itself was later reconverted into various different divinities, while the `sacred doors' of the Great Goddess and/or the dragons (offspring of Mother Earth and generally regarded as Keepers of the Doors) persisted in more recent mythologies. Piccardi L., 1999: The "Footprints" of the Archangel: Evidence of Early-Medieval Surface Faulting at Monte Sant'Angelo (Gargano, Italy

  1. THE ACTIVE FAULTS OF EURASIA DATABASE

    Directory of Open Access Journals (Sweden)

    D. M. Bachmanov

    2017-01-01

    Full Text Available This paper describes the technique used to create and maintain the Active Faults of Eurasia Database (AFED based on the uniform format that ensures integrating the materials accumulated by many researchers, inclu­ding the authors of the AFED. The AFED includes the data on more than 20 thousand objects: faults, fault zones and associated structural forms that show the signs of latest displacements in the Late Pleistocene and Holocene. The geographical coordinates are given for each object. The AFED scale is 1:500000; the demonstration scale is 1:1000000. For each object, the AFED shows two kinds of characteristics: justification attributes, and estimated attributes. The justification attributes inform the AFED user about an object: the object’s name; morphology; kinematics; the amplitudes of displacement for different periods of time; displacement rates estimated from the amplitudes; the age of the latest recorded signs of activity, seismicity and paleoseismicity; the relationship of the given objects with the parameters of crustal earthquakes; etc. The sources of information are listed in the AFED appendix. The estimated attributes are represented by the system of indices reflecting the fault kinematics according to the classification of the faults by types, as accepted in structural geology, and includes three ranks of the Late Quaternary movements and four degrees of reliability of identifying the structures as active ones. With reference to the indices, the objects can be compared with each other, considering any of the attributes, or with any other digitized information. The comparison can be performed by any GIS software. The AFED is an efficient tool for obtaining the information on the faults and solving general problems, such as thematic mapping, determining the parameters of modern geodynamic processes, estima­ting seismic and other geodynamic hazards, identifying the tectonic development trends in the Pliocene–Quaternary stage of

  2. LAMPF first-fault identifier for fast transient faults

    International Nuclear Information System (INIS)

    Swanson, A.R.; Hill, R.E.

    1979-01-01

    The LAMPF accelerator is presently producing 800-MeV proton beams at 0.5 mA average current. Machine protection for such a high-intensity accelerator requires a fast shutdown mechanism, which can turn off the beam within a few microseconds of the occurrence of a machine fault. The resulting beam unloading transients cause the rf systems to exceed control loop tolerances and consequently generate multiple fault indications for identification by the control computer. The problem is to isolate the primary fault or cause of beam shutdown while disregarding as many as 50 secondary fault indications that occur as a result of beam shutdown. The LAMPF First-Fault Identifier (FFI) for fast transient faults is operational and has proven capable of first-fault identification. The FFI design utilized features of the Fast Protection System that were previously implemented for beam chopping and rf power conservation. No software changes were required

  3. Search for the in-phase Flux Flow mode in stacked Josephson junctions

    DEFF Research Database (Denmark)

    Pedersen, Niels Falsig; Madsen, Søren Peder

    2006-01-01

    Josephson vortex flux flow states in stacked Josephson junctions are investigated numerically. The aim of the work is to understand the mechanisms behind the formation of triangular (anti-phase) and square (in-phase) vortex lattices, and is motivated by recent experiments on layered BSCCO type high......-T-c superconductors in a magnetic field. In order to keep the problem as simple as possible we consider in detail only the case with two junctions in the stack. (c) 2006 Elsevier B.V. All rights reserved....

  4. Time contour expression of limited range phenomena on stack chart; Jugo chart jo deno kyokuchi gensho jikan contour

    Energy Technology Data Exchange (ETDEWEB)

    Kametani, T

    1997-05-27

    Time contour expression of limited range phenomena on stack chart is examined for further improvement on the result of the ultimate interpretation in the seismic reflection survey. The policy is made clear from the beginning that local phenomena are to be discussed, and data prior CMP stacking is interpreted in detail. For this purpose, it is effective to make use of the time contour expression in the midpoint-offset plane simultaneously with the CMP and COP panels. For the review of data prior to CMP stacking, it is convenient to use the CMP (CDP) stacking chart in which the data is arranged methodically. In this chart, all the channels which are crude data prior to stacking are plotted on midpoint-offset coordinates, which plane is called the MOD (Midpoint Offset Domain) panel. Various panels can be chosen unrestrictedly, and their mutual relations can be easily grasped. When data points are given a time axis, they can be expressed in a time contour. Studies are conducted about the underground structure, multiple reflection paths divided by it, and characteristics of detour reflection attributable to faults. 4 refs., 9 figs.

  5. Stacked spheres and lower bound theorem

    Indian Academy of Sciences (India)

    BASUDEB DATTA

    2011-11-20

    Nov 20, 2011 ... Preliminaries. Lower bound theorem. On going work. Definitions. An n-simplex is a convex hull of n + 1 affinely independent points. (called vertices) in some Euclidean space R. N . Stacked spheres and lower bound theorem. Basudeb Datta. Indian Institute of Science. 2 / 27 ...

  6. Contemporary sample stacking in analytical electrophoresis

    Czech Academy of Sciences Publication Activity Database

    Šlampová, Andrea; Malá, Zdeňka; Pantůčková, Pavla; Gebauer, Petr; Boček, Petr

    2013-01-01

    Roč. 34, č. 1 (2013), s. 3-18 ISSN 0173-0835 R&D Projects: GA ČR GAP206/10/1219 Institutional support: RVO:68081715 Keywords : biological samples * stacking * trace analysis * zone electrophoresis Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.161, year: 2013

  7. SRS reactor stack plume marking tests

    International Nuclear Information System (INIS)

    Petry, S.F.

    1992-03-01

    Tests performed in 105-K in 1987 and 1988 demonstrated that the stack plume can successfully be made visible (i.e., marked) by introducing smoke into the stack breech. The ultimate objective of these tests is to provide a means during an emergency evacuation so that an evacuee can readily identify the stack plume and evacuate in the opposite direction, thus minimizing the potential of severe radiation exposure. The EPA has also requested DOE to arrange for more tests to settle a technical question involving the correct calculation of stack downwash. New test canisters were received in 1988 designed to produce more smoke per unit time; however, these canisters have not been evaluated, because normal ventilation conditions have not been reestablished in K Area. Meanwhile, both the authorization and procedure to conduct the tests have expired. The tests can be performed during normal reactor operation. It is recommended that appropriate authorization and procedure approval be obtained to resume testing after K Area restart

  8. Scaling the CERN OpenStack cloud

    Science.gov (United States)

    Bell, T.; Bompastor, B.; Bukowiec, S.; Castro Leon, J.; Denis, M. K.; van Eldik, J.; Fermin Lobo, M.; Fernandez Alvarez, L.; Fernandez Rodriguez, D.; Marino, A.; Moreira, B.; Noel, B.; Oulevey, T.; Takase, W.; Wiebalck, A.; Zilli, S.

    2015-12-01

    CERN has been running a production OpenStack cloud since July 2013 to support physics computing and infrastructure services for the site. In the past year, CERN Cloud Infrastructure has seen a constant increase in nodes, virtual machines, users and projects. This paper will present what has been done in order to make the CERN cloud infrastructure scale out.

  9. Stacking non-BPS D-branes

    International Nuclear Information System (INIS)

    Alberghi, Gian Luigi; Caceres, Elena; Goldstein, Kevin; Lowe, David A. . lowe@het.brown.edu

    2001-08-01

    We present a candidate supergravity solution for a stacked configuration of stable non-BPS D-branes in Type II string theory compactified on T 4 /Z 2 . This gives a supergravity description of nonabelian tachyon condensation on the brane woldvolume. (author)

  10. Trace interpolation by slant-stack migration

    International Nuclear Information System (INIS)

    Novotny, M.

    1990-01-01

    The slant-stack migration formula based on the radon transform is studied with respect to the depth steep Δz of wavefield extrapolation. It can be viewed as a generalized trace-interpolation procedure including wave extrapolation with an arbitrary step Δz. For Δz > 0 the formula yields the familiar plane-wave decomposition, while for Δz > 0 it provides a robust tool for migration transformation of spatially under sampled wavefields. Using the stationary phase method, it is shown that the slant-stack migration formula degenerates into the Rayleigh-Sommerfeld integral in the far-field approximation. Consequently, even a narrow slant-stack gather applied before the diffraction stack can significantly improve the representation of noisy data in the wavefield extrapolation process. The theory is applied to synthetic and field data to perform trace interpolation and dip reject filtration. The data examples presented prove that the radon interpolator works well in the dip range, including waves with mutual stepouts smaller than half the dominant period

  11. Contemporary sample stacking in analytical electrophoresis

    Czech Academy of Sciences Publication Activity Database

    Malá, Zdeňka; Šlampová, Andrea; Křivánková, Ludmila; Gebauer, Petr; Boček, Petr

    2015-01-01

    Roč. 36, č. 1 (2015), s. 15-35 ISSN 0173-0835 R&D Projects: GA ČR(CZ) GA13-05762S Institutional support: RVO:68081715 Keywords : biological samples * stacking * trace analysis * zone electrophoresis Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.482, year: 2015

  12. 40 CFR 61.53 - Stack sampling.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Stack sampling. 61.53 Section 61.53 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL... sampling. (a) Mercury ore processing facility. (1) Unless a waiver of emission testing is obtained under...

  13. 40 CFR 61.33 - Stack sampling.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Stack sampling. 61.33 Section 61.33 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL... sampling. (a) Unless a waiver of emission testing is obtained under § 61.13, each owner or operator...

  14. OpenStack cloud computing cookbook

    CERN Document Server

    Jackson, Kevin

    2013-01-01

    A Cookbook full of practical and applicable recipes that will enable you to use the full capabilities of OpenStack like never before.This book is aimed at system administrators and technical architects moving from a virtualized environment to cloud environments with familiarity of cloud computing platforms. Knowledge of virtualization and managing linux environments is expected.

  15. Toward advising SME's on stacked funding

    NARCIS (Netherlands)

    Rauwerda, Kirsten; van Teeffelen, Lex; de Graaf, Frank Jan

    2017-01-01

    This paper addresses new funding issues faced by SMEs. Over a period of nine months, the authors conducted a preliminary study into the problems surrounding stacked funding faced by SMEs and their financial advisers. The study includes a short literature review, the outcomes of three round table

  16. Optoelectronic interconnects for 3D wafer stacks

    Science.gov (United States)

    Ludwig, David; Carson, John C.; Lome, Louis S.

    1996-01-01

    Wafer and chip stacking are envisioned as means of providing increased processing power within the small confines of a three-dimensional structure. Optoelectronic devices can play an important role in these dense 3-D processing electronic packages in two ways. In pure electronic processing, optoelectronics can provide a method for increasing the number of input/output communication channels within the layers of the 3-D chip stack. Non-free space communication links allow the density of highly parallel input/output ports to increase dramatically over typical edge bus connections. In hybrid processors, where electronics and optics play a role in defining the computational algorithm, free space communication links are typically utilized for, among other reasons, the increased network link complexity which can be achieved. Free space optical interconnections provide bandwidths and interconnection complexity unobtainable in pure electrical interconnections. Stacked 3-D architectures can provide the electronics real estate and structure to deal with the increased bandwidth and global information provided by free space optical communications. This paper will provide definitions and examples of 3-D stacked architectures in optoelectronics processors. The benefits and issues of these technologies will be discussed.

  17. OpenStack Object Storage (Swift) essentials

    CERN Document Server

    Kapadia, Amar; Varma, Sreedhar

    2015-01-01

    If you are an IT administrator and you want to enter the world of cloud storage using OpenStack Swift, then this book is ideal for you. Basic knowledge of Linux and server technology is beneficial to get the most out of the book.

  18. Fault-tolerant computing systems

    International Nuclear Information System (INIS)

    Dal Cin, M.; Hohl, W.

    1991-01-01

    Tests, Diagnosis and Fault Treatment were chosen as the guiding themes of the conference. However, the scope of the conference included reliability, availability, safety and security issues in software and hardware systems as well. The sessions were organized for the conference which was completed by an industrial presentation: Keynote Address, Reconfiguration and Recover, System Level Diagnosis, Voting and Agreement, Testing, Fault-Tolerant Circuits, Array Testing, Modelling, Applied Fault Tolerance, Fault-Tolerant Arrays and Systems, Interconnection Networks, Fault-Tolerant Software. One paper has been indexed separately in the database. (orig./HP)

  19. Fault rocks and uranium mineralization

    International Nuclear Information System (INIS)

    Tong Hangshou.

    1991-01-01

    The types of fault rocks, microstructural characteristics of fault tectonite and their relationship with uranium mineralization in the uranium-productive granite area are discussed. According to the synthetic analysis on nature of stress, extent of crack and microstructural characteristics of fault rocks, they can be classified into five groups and sixteen subgroups. The author especially emphasizes the control of cataclasite group and fault breccia group over uranium mineralization in the uranium-productive granite area. It is considered that more effective study should be made on the macrostructure and microstructure of fault rocks. It is of an important practical significance in uranium exploration

  20. Network Fault Diagnosis Using DSM

    Institute of Scientific and Technical Information of China (English)

    Jiang Hao; Yan Pu-liu; Chen Xiao; Wu Jing

    2004-01-01

    Difference similitude matrix (DSM) is effective in reducing information system with its higher reduction rate and higher validity. We use DSM method to analyze the fault data of computer networks and obtain the fault diagnosis rules. Through discretizing the relative value of fault data, we get the information system of the fault data. DSM method reduces the information system and gets the diagnosis rules. The simulation with the actual scenario shows that the fault diagnosis based on DSM can obtain few and effective rules.

  1. Texture-dependent twin formation in nanocrystalline thin Pd films

    International Nuclear Information System (INIS)

    Wang, B.; Idrissi, H.; Shi, H.; Colla, M.S.; Michotte, S.; Raskin, J.P.; Pardoen, T.; Schryvers, D.

    2012-01-01

    Nanocrystalline Pd films were produced by electron-beam evaporation and sputter deposition. The electron-beam-evaporated films reveal randomly oriented nanograins with a relatively high density of growth twins, unexpected in view of the high stacking fault energy of Pd. In contrast, sputter-deposited films show a clear 〈1 1 1〉 crystallographic textured nanostructure without twins. These results provide insightful information to guide the generation of microstructures with enhanced strength/ductility balance in high stacking fault energy nanocrystalline metallic thin films.

  2. Preliminary paleoseismic observations along the western Denali fault, Alaska

    Science.gov (United States)

    Koehler, R. D.; Schwartz, D. P.; Rood, D. H.; Reger, R.; Wolken, G. J.

    2013-12-01

    the fan across the main fault scarp and adjacent graben, exposed sheared debris fan parent material at its north and south ends, separated by a central zone of stacked scarp-derived colluvium and weakly developed peaty soils. Stratigraphic relations and upward fault terminations clearly record the occurrence of the past three surface-faulting earthquakes and suggest four or more such events. Results of pending 14C analyses are expected to provide new information on earthquake timing and recurrence. A Holocene slip rate for this section of the fault will be developed using back-slip models and an estimate of the age of the fan constrained by our detailed surveys of channel offsets and pending cosmogenic 10Be exposure ages for surface boulders, respectively.

  3. Vacancy enhanced formation and phase transition of Cu-rich precipitates in α - iron under neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lv, G. C. [Basic Experimental Center of Natural Science, University of Science and Technology Beijing, Beijing, 100083 (China); Corrosion and Protection Center, Key Laboratory of Environmental Fracture (MOE), University of Science and Technology Beijing, Beijing, 100083 (China); Zhang, H. [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Canada, T6G2V4 (Canada); He, X. F.; Yang, W. [China Institute of Atomic Energy, Beijing, 102413 (China); Su, Y. J., E-mail: yjsu@ustb.edu.cn [Corrosion and Protection Center, Key Laboratory of Environmental Fracture (MOE), University of Science and Technology Beijing, Beijing, 100083 (China)

    2016-04-15

    In this paper, we employed both molecular statics and molecular dynamics simulation methods to investigate the role of vacancies in the formation and phase transition of Cu-rich precipitates in α-iron. The results indicated that vacancies promoted the diffusion of Cu atoms to form Cu-rich precipitates. After Cu-rich precipitates formed, they further trapped vacancies. The supersaturated vacancy concentration in the Cu-rich precipitate induced a shear strain, which triggered the phase transition from bcc to fcc structure by transforming the initial bcc (110) plane into fcc (111) plane. In addition, the formation of the fcc-twin structure and the stacking fault structure in the Cu-rich precipitates was observed in dynamics simulations.

  4. AFTC Code for Automatic Fault Tree Construction: Users Manual

    International Nuclear Information System (INIS)

    Gopika Vinod; Saraf, R.K.; Babar, A.K.

    1999-04-01

    Fault Trees perform a predominant role in reliability and safety analysis of system. Manual construction of fault tree is a very time consuming task and moreover, it won't give a formalized result, since it relies highly on analysts experience and heuristics. This necessitates a computerised fault tree construction, which is still attracting interest of reliability analysts. AFTC software is a user friendly software model for constructing fault trees based on decision tables. Software is equipped with libraries of decision tables for components commonly used in various Nuclear Power Plant (NPP) systems. User is expected to make a nodal diagram of the system, for which fault tree is to be constructed, from the flow sheets available. The text nodal diagram goes as the sole input defining the system flow chart. AFTC software is a rule based expert system which draws the fault tree from the system flow chart and component decision tables. AFTC software gives fault tree in both text and graphic format. Help is provided as how to enter system flow chart and component decision tables. The software is developed in 'C' language. Software is verified with simplified version of the fire water system of an Indian PHWR. Code conversion will be undertaken to create a window based version. (author)

  5. On a semiclassical analysis of high energy electron diffraction by imperfect crystals: the stacking fault

    International Nuclear Information System (INIS)

    Smith, A.E.; Chadderton, L.T.; Johnson, E.

    1978-01-01

    Electron diffraction amplitudes at the lower surface of a displaced sandwich crystal are obtained for the high energy limit in the real space formulation. Using semiclassical methods analytical approximations to a resulting overlap integral - central to the problem - are derived. (Auth.)

  6. A semiclassical analysis of high energy electron diffraction by stacking faults: arrival at the classical limit

    International Nuclear Information System (INIS)

    Smith, A.E.; Chadderton, L.T.

    1978-01-01

    In a recent note the authors summarised results for an extension of Berry's theory to cover the one-dimensional problem of systematic reflections (planes) for a thin crystal sandwich consisting of two identical slabs of lattice parameter 'a' with a relative horizontal displacement 'f'. The diffraction amplitudes at the lower surface of the crystal were shown to depend on a double summation over the various transverse energy states in the upper and lower slab respectively, and on the transitions between them. In this report the authors demonstrate the arrival at the classical limit for the problem and, in particular, indicate briefly the nature of the topologically different classical paths. (Auth.)

  7. New method of experimental evaluation of stacking fault energy in d-transition metals

    International Nuclear Information System (INIS)

    Dekhtyar, A.I.; Kozyrsky, G.Ya.; Kononenko, V.A.

    1976-01-01

    The positron-electron annihilation method is the most useful to study the electron structure near the dislocation cores. It follows from the analysis of angular correlation curves for γ-quanta of d-transition metals that sp- and spd-electrons may be treated as two Fermi-gases It has been concluded that d-like electrons reveal the behavior of both the collectivized and localized type. The splitting width, ω, of edge dislocations in various d-metals has been determined. Interesting data have been obtained for Mo single crystals deformed under different conditions: cold working (tensile test at room temperature); warm working (rolling at 300 deg C); hot working (creep at 1360 deg C)

  8. A model for crack-induced nucleation of dislocations, complex stacking faults, and twins

    Czech Academy of Sciences Publication Activity Database

    Beltz, G. E.; Chang, M.; Machová, Anna

    2005-01-01

    Roč. 482, - (2005), s. 17-25 ISSN 0255-5476. [Materials Structure & Micromechanics of Fracture /4./. Brno, 23.06.2004-25.06.2004] R&D Projects: GA MŠk ME 504; GA AV ČR IAA2076201 Institutional research plan: CEZ:AV0Z20760514 Keywords : crack * dislocations * twins Subject RIV: JG - Metallurgy Impact factor: 0.399, year: 2005

  9. Faults in Linux

    DEFF Research Database (Denmark)

    Palix, Nicolas Jean-Michel; Thomas, Gaël; Saha, Suman

    2011-01-01

    In 2001, Chou et al. published a study of faults found by applying a static analyzer to Linux versions 1.0 through 2.4.1. A major result of their work was that the drivers directory contained up to 7 times more of certain kinds of faults than other directories. This result inspired a number...... of development and research efforts on improving the reliability of driver code. Today Linux is used in a much wider range of environments, provides a much wider range of services, and has adopted a new development and release model. What has been the impact of these changes on code quality? Are drivers still...... a major problem? To answer these questions, we have transported the experiments of Chou et al. to Linux versions 2.6.0 to 2.6.33, released between late 2003 and early 2010. We find that Linux has more than doubled in size during this period, but that the number of faults per line of code has been...

  10. Methanogenic archaea isolated from Taiwan's Chelungpu fault.

    Science.gov (United States)

    Wu, Sue-Yao; Lai, Mei-Chin

    2011-02-01

    Terrestrial rocks, petroleum reservoirs, faults, coal seams, and subseafloor gas hydrates contain an abundance of diverse methanoarchaea. However, reports on the isolation, purification, and characterization of methanoarchaea in the subsurface environment are rare. Currently, no studies investigating methanoarchaea within fault environments exist. In this report, we succeeded in obtaining two new methanogen isolates, St545Mb(T) of newly proposed species Methanolobus chelungpuianus and Methanobacterium palustre FG694aF, from the Chelungpu fault, which is the fault that caused a devastating earthquake in central Taiwan in 1999. Strain FG694aF was isolated from a fault gouge sample obtained at 694 m below land surface (mbls) and is an autotrophic, mesophilic, nonmotile, thin, filamentous-rod-shaped organism capable of using H(2)-CO(2) and formate as substrates for methanogenesis. The morphological, biochemical, and physiological characteristics and 16S rRNA gene sequence analysis revealed that this isolate belongs to Methanobacterium palustre. The mesophilic strain St545Mb(T), isolated from a sandstone sample at 545 mbls, is a nonmotile, irregular, coccoid organism that uses methanol and trimethylamine as substrates for methanogenesis. The 16S rRNA gene sequence of strain St545Mb(T) was 99.0% similar to that of Methanolobus psychrophilus strain R15 and was 96 to 97.5% similar to the those of other Methanolobus species. However, the optimal growth temperature and total cell protein profile of strain St545Mb(T) were different from those of M. psychrophilus strain R15, and whole-genome DNA-DNA hybridization revealed less than 20% relatedness between these two strains. On the basis of these observations, we propose that strain St545Mb(T) (DSM 19953(T); BCRC AR10030; JCM 15159) be named Methanolobus chelungpuianus sp. nov. Moreover, the environmental DNA database survey indicates that both Methanolobus chelungpuianus and Methanobacterium palustre are widespread in the

  11. The Sorong Fault Zone, Indonesia: Mapping a Fault Zone Offshore

    Science.gov (United States)

    Melia, S.; Hall, R.

    2017-12-01

    The Sorong Fault Zone is a left-lateral strike-slip fault zone in eastern Indonesia, extending westwards from the Bird's Head peninsula of West Papua towards Sulawesi. It is the result of interactions between the Pacific, Caroline, Philippine Sea, and Australian Plates and much of it is offshore. Previous research on the fault zone has been limited by the low resolution of available data offshore, leading to debates over the extent, location, and timing of movements, and the tectonic evolution of eastern Indonesia. Different studies have shown it north of the Sula Islands, truncated south of Halmahera, continuing to Sulawesi, or splaying into a horsetail fan of smaller faults. Recently acquired high resolution multibeam bathymetry of the seafloor (with a resolution of 15-25 meters), and 2D seismic lines, provide the opportunity to trace the fault offshore. The position of different strands can be identified. On land, SRTM topography shows that in the northern Bird's Head the fault zone is characterised by closely spaced E-W trending faults. NW of the Bird's Head offshore there is a fold and thrust belt which terminates some strands. To the west of the Bird's Head offshore the fault zone diverges into multiple strands trending ENE-WSW. Regions of Riedel shearing are evident west of the Bird's Head, indicating sinistral strike-slip motion. Further west, the ENE-WSW trending faults turn to an E-W trend and there are at least three fault zones situated immediately south of Halmahera, north of the Sula Islands, and between the islands of Sanana and Mangole where the fault system terminates in horsetail strands. South of the Sula islands some former normal faults at the continent-ocean boundary with the North Banda Sea are being reactivated as strike-slip faults. The fault zone does not currently reach Sulawesi. The new fault map differs from previous interpretations concerning the location, age and significance of different parts of the Sorong Fault Zone. Kinematic

  12. Project W-420 Stack Monitoring system upgrades conceptual design report

    International Nuclear Information System (INIS)

    TUCK, J.A.

    1998-01-01

    This document describes the scope, justification, conceptual design, and performance of Project W-420 stack monitoring system upgrades on six NESHAP-designated, Hanford Tank Farms ventilation exhaust stacks

  13. Project W-420 Stack Monitoring system upgrades conceptual design report

    Energy Technology Data Exchange (ETDEWEB)

    TUCK, J.A.

    1998-11-06

    This document describes the scope, justification, conceptual design, and performance of Project W-420 stack monitoring system upgrades on six NESHAP-designated, Hanford Tank Farms ventilation exhaust stacks.

  14. Generalized planar fault energies and twinning in Cu-Al alloys

    Science.gov (United States)

    Kibey, S.; Liu, J. B.; Johnson, D. D.; Sehitoglu, H.

    2006-11-01

    We report ab initio density functional theory calculations of generalized planar fault energies of fcc Cu -xAl (x =0, 5.0, and 8.3at.%) alloys. We investigate the effects of substitutional solute Al on the unstable intrinsic γus and twin γut stacking fault energies (SFEs). Our results reveal an increased tendency of Cu-Al to deform preferentially by twinning with increasing Al content, consistent with experiment. We attribute this mechanical behavior to appreciable lowering of the twinning barrier γut, along with the stable intrinsic and twin SFEs.

  15. Laboratory scale micro-seismic monitoring of rock faulting and injection-induced fault reactivation

    Science.gov (United States)

    Sarout, J.; Dautriat, J.; Esteban, L.; Lumley, D. E.; King, A.

    2017-12-01

    The South West Hub CCS project in Western Australia aims to evaluate the feasibility and impact of geosequestration of CO2 in the Lesueur sandstone formation. Part of this evaluation focuses on the feasibility and design of a robust passive seismic monitoring array. Micro-seismicity monitoring can be used to image the injected CO2plume, or any geomechanical fracture/fault activity; and thus serve as an early warning system by measuring low-level (unfelt) seismicity that may precede potentially larger (felt) earthquakes. This paper describes laboratory deformation experiments replicating typical field scenarios of fluid injection in faulted reservoirs. Two pairs of cylindrical core specimens were recovered from the Harvey-1 well at depths of 1924 m and 2508 m. In each specimen a fault is first generated at the in situ stress, pore pressure and temperature by increasing the vertical stress beyond the peak in a triaxial stress vessel at CSIRO's Geomechanics & Geophysics Lab. The faulted specimen is then stabilized by decreasing the vertical stress. The freshly formed fault is subsequently reactivated by brine injection and increase of the pore pressure until slip occurs again. This second slip event is then controlled in displacement and allowed to develop for a few millimeters. The micro-seismic (MS) response of the rock during the initial fracturing and subsequent reactivation is monitored using an array of 16 ultrasonic sensors attached to the specimen's surface. The recorded MS events are relocated in space and time, and correlate well with the 3D X-ray CT images of the specimen obtained post-mortem. The time evolution of the structural changes induced within the triaxial stress vessel is therefore reliably inferred. The recorded MS activity shows that, as expected, the increase of the vertical stress beyond the peak led to an inclined shear fault. The injection of fluid and the resulting increase in pore pressure led first to a reactivation of the pre

  16. ESR dating of fault rocks

    International Nuclear Information System (INIS)

    Lee, Hee Kwon

    2003-02-01

    Past movement on faults can be dated by measurement of the intensity of ESR signals in quartz. These signals are reset by local lattice deformation and local frictional heating on grain contacts at the time of fault movement. The ESR signals then grow back as a result of bombardment by ionizing radiation from surrounding rocks. The age is obtained from the ratio of the equivalent dose, needed to produce the observed signal, to the dose rate. Fine grains are more completely reset during faulting, and a plot of age vs. grain size shows a plateau for grains below critical size; these grains are presumed to have been completely zeroed by the last fault activity. We carried out ESR dating of fault rocks collected near the Gori nuclear reactor. Most of the ESR signals of fault rocks collected from the basement are saturated. This indicates that the last movement of the faults had occurred before the Quaternary period. However, ESR dates from the Oyong fault zone range from 370 to 310 ka. Results of this research suggest that long-term cyclic fault activity of the Oyong fault zone continued into the Pleistocene

  17. Large earthquakes and creeping faults

    Science.gov (United States)

    Harris, Ruth A.

    2017-01-01

    Faults are ubiquitous throughout the Earth's crust. The majority are silent for decades to centuries, until they suddenly rupture and produce earthquakes. With a focus on shallow continental active-tectonic regions, this paper reviews a subset of faults that have a different behavior. These unusual faults slowly creep for long periods of time and produce many small earthquakes. The presence of fault creep and the related microseismicity helps illuminate faults that might not otherwise be located in fine detail, but there is also the question of how creeping faults contribute to seismic hazard. It appears that well-recorded creeping fault earthquakes of up to magnitude 6.6 that have occurred in shallow continental regions produce similar fault-surface rupture areas and similar peak ground shaking as their locked fault counterparts of the same earthquake magnitude. The behavior of much larger earthquakes on shallow creeping continental faults is less well known, because there is a dearth of comprehensive observations. Computational simulations provide an opportunity to fill the gaps in our understanding, particularly of the dynamic processes that occur during large earthquake rupture and arrest.

  18. ESR dating of fault rocks

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hee Kwon [Kangwon National Univ., Chuncheon (Korea, Republic of)

    2003-02-15

    Past movement on faults can be dated by measurement of the intensity of ESR signals in quartz. These signals are reset by local lattice deformation and local frictional heating on grain contacts at the time of fault movement. The ESR signals then grow back as a result of bombardment by ionizing radiation from surrounding rocks. The age is obtained from the ratio of the equivalent dose, needed to produce the observed signal, to the dose rate. Fine grains are more completely reset during faulting, and a plot of age vs. grain size shows a plateau for grains below critical size; these grains are presumed to have been completely zeroed by the last fault activity. We carried out ESR dating of fault rocks collected near the Gori nuclear reactor. Most of the ESR signals of fault rocks collected from the basement are saturated. This indicates that the last movement of the faults had occurred before the Quaternary period. However, ESR dates from the Oyong fault zone range from 370 to 310 ka. Results of this research suggest that long-term cyclic fault activity of the Oyong fault zone continued into the Pleistocene.

  19. Deep rock damage in the San Andreas Fault revealed by P- and S-type fault-zone-guided waves

    Science.gov (United States)

    Ellsworth, William L.; Malin, Peter E.

    2011-01-01

    Damage to fault-zone rocks during fault slip results in the formation of a channel of low seismic-wave velocities. Within such channels guided seismic waves, denoted by Fg, can propagate. Here we show with core samples, well logs and Fg-waves that such a channel is crossed by the SAFOD (San Andreas Fault Observatory at Depth) borehole at a depth of 2.7 km near Parkfield, California, USA. This laterally extensive channel extends downwards to at least half way through the seismogenic crust, more than about 7 km. The channel supports not only the previously recognized Love-type- (FL) and Rayleigh-type- (FR) guided waves, but also a new fault-guided wave, which we name FF. As recorded 2.7 km underground, FF is normally dispersed, ends in an Airy phase, and arrives between the P- and S-waves. Modelling shows that FF travels as a leaky mode within the core of the fault zone. Combined with the drill core samples, well logs and the two other types of guided waves, FF at SAFOD reveals a zone of profound, deep, rock damage. Originating from damage accumulated over the recent history of fault movement, we suggest it is maintained either by fracturing near the slip surface of earthquakes, such as the 1857 Fort Tejon M 7.9, or is an unexplained part of the fault-creep process known to be active at this site.

  20. Real-time fault diagnosis and fault-tolerant control

    OpenAIRE

    Gao, Zhiwei; Ding, Steven X.; Cecati, Carlo

    2015-01-01

    This "Special Section on Real-Time Fault Diagnosis and Fault-Tolerant Control" of the IEEE Transactions on Industrial Electronics is motivated to provide a forum for academic and industrial communities to report recent theoretic/application results in real-time monitoring, diagnosis, and fault-tolerant design, and exchange the ideas about the emerging research direction in this field. Twenty-three papers were eventually selected through a strict peer-reviewed procedure, which represent the mo...

  1. Estimating fault stability and sustainable fluid pressures for underground storage of CO2 in porous rock

    International Nuclear Information System (INIS)

    Streit, J.E.; Hillis, R.R.

    2004-01-01

    Geomechanical modelling of fault stability is an integral part of Australia's GEODISC research program to ensure the safe storage of carbon dioxide in subsurface reservoirs. Storage of CO 2 in deep saline formations or depleted hydrocarbon reservoirs requires estimates of sustainable fluid pressures that will not induce fracturing or create fault permeability that could lead to CO 2 escape. Analyses of fault stability require the determination of fault orientations, ambient pore fluid pressures and in situ stresses in a potential storage site. The calculation of effective stresses that act on faults and reservoir rocks lead then to estimates of fault slip tendency and fluid pressures sustainable during CO 2 storage. These parameters can be visualized on 3D images of fault surfaces or in 2D projections. Faults that are unfavourably oriented for reactivation can be identified from failure plots. In depleted oil and gas fields, modelling of fault and rock stability needs to incorporate changes of the pre-production stresses that were induced by hydrocarbon production and associated pore pressure depletion. Such induced stress changes influence the maximum sustainable formation pressures and CO 2 storage volumes. Hence, determination of in situ stresses and modelling of fault stability are essential prerequisites for the safe engineering of subsurface CO 2 injection and the modelling of storage capacity. (author)

  2. Shallow electromagnetic data from three known fault zones in the Paradox Basin, Utah

    International Nuclear Information System (INIS)

    Watts, R.D.

    1981-01-01

    This report describes a preliminary investigation of the effectiveness of two electromagnetic exploration methods as means of finding unmapped faults in the Paradox Basin environment. Results indicate that the Very Low Frequency (VLF) method is useful. VLF profiles were measured across three known fault traces near Gibson Dome, San Juan County, Utah. Each fault or set of faults generated a significant anomaly. In some cases, the anomaly due to the fault was superimposed on a larger scale anomaly caused by the transition from unaltered rocks away from the fault to altered rocks in or on one side of the fault zone. In one case, the lithology of the surface rocks was different on the two sides of the fault (Kayenta Formation to the northwest. Navajo Sandstone to the southeast), so the signature of the fault itself was superimposed on the signature of the transition between formations. In addition to the VLF surveys, one line of high-frequency loop-loop induction measurements was taken, using an instrument with a 4-meter loop separation. The method did not appear to locate faults successfully; further experiments using greater loop spacings need to be done

  3. Multistage Force Amplification of Piezoelectric Stacks

    Science.gov (United States)

    Xu, Tian-Bing (Inventor); Siochi, Emilie J. (Inventor); Zuo, Lei (Inventor); Jiang, Xiaoning (Inventor); Kang, Jin Ho (Inventor)

    2015-01-01

    Embodiments of the disclosure include an apparatus and methods for using a piezoelectric device, that includes an outer flextensional casing, a first cell and a last cell serially coupled to each other and coupled to the outer flextensional casing such that each cell having a flextensional cell structure and each cell receives an input force and provides an output force that is amplified based on the input force. The apparatus further includes a piezoelectric stack coupled to each cell such that the piezoelectric stack of each cell provides piezoelectric energy based on the output force for each cell. Further, the last cell receives an input force that is the output force from the first cell and the last cell provides an output apparatus force In addition, the piezoelectric energy harvested is based on the output apparatus force. Moreover, the apparatus provides displacement based on the output apparatus force.

  4. Radiation-Tolerant Intelligent Memory Stack - RTIMS

    Science.gov (United States)

    Ng, Tak-kwong; Herath, Jeffrey A.

    2011-01-01

    This innovation provides reconfigurable circuitry and 2-Gb of error-corrected or 1-Gb of triple-redundant digital memory in a small package. RTIMS uses circuit stacking of heterogeneous components and radiation shielding technologies. A reprogrammable field-programmable gate array (FPGA), six synchronous dynamic random access memories, linear regulator, and the radiation mitigation circuits are stacked into a module of 42.7 42.7 13 mm. Triple module redundancy, current limiting, configuration scrubbing, and single- event function interrupt detection are employed to mitigate radiation effects. The novel self-scrubbing and single event functional interrupt (SEFI) detection allows a relatively soft FPGA to become radiation tolerant without external scrubbing and monitoring hardware

  5. Development of on-site PAFC stacks

    Energy Technology Data Exchange (ETDEWEB)

    Hotta, K.; Matsumoto, Y. [Kansai Electric Power Co., Amagasaki (Japan); Horiuchi, H.; Ohtani, T. [Mitsubishi Electric Corp., Kobe (Japan)

    1996-12-31

    PAFC (Phosphoric Acid Fuel Cell) has been researched for commercial use and demonstration plants have been installed in various sites. However, PAFC don`t have a enough stability yet, so more research and development must be required in the future. Especially, cell stack needs a proper state of three phases (liquid, gas and solid) interface. It is very difficult technology to keep this condition for a long time. In the small size cell with the electrode area of 100 cm{sup 2}, gas flow and temperature distributions show uniformity. But in the large size cell with the electrode area of 4000 cm{sup 2}, the temperature distributions show non-uniformity. These distributions would cause to be shorten the cell life. Because these distributions make hot-spot and gas poverty in limited parts. So we inserted thermocouples in short-stack for measuring three-dimensional temperature distributions and observed effects of current density and gas utilization on temperature.

  6. System for inspection of stacked cargo containers

    Science.gov (United States)

    Derenzo, Stephen [Pinole, CA

    2011-08-16

    The present invention relates to a system for inspection of stacked cargo containers. One embodiment of the invention generally comprises a plurality of stacked cargo containers arranged in rows or tiers, each container having a top, a bottom a first side, a second side, a front end, and a back end; a plurality of spacers arranged in rows or tiers; one or more mobile inspection devices for inspecting the cargo containers, wherein the one or more inspection devices are removeably disposed within the spacers, the inspection means configured to move through the spacers to detect radiation within the containers. The invented system can also be configured to inspect the cargo containers for a variety of other potentially hazardous materials including but not limited to explosive and chemical threats.

  7. Industrial stacks design; Diseno de chimeneas industriales

    Energy Technology Data Exchange (ETDEWEB)

    Cacheux, Luis [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1987-12-31

    The Instituto de Investigaciones Electricas (IIE) though its Civil Works Department, develops, under contract with CFE`s Gerencia de Proyectos Termoelectricos (Management of Fossil Power Plant Projects), a series of methods for the design of stacks, which pretends to solve the a present day problem: the stack design of the fossil power plants that will go into operation during the next coming years in the country. [Espanol] El Instituto de Investigaciones Electricas (IIE), a traves del Departamento de Ingenieria Civil, desarrolla, bajo contrato con la Gerencia de Proyectos Termoelectricos, de la Comision Federal de Electricidad (CFE), un conjunto de metodos para el diseno de chimeneas, con el que se pretende resolver un problema inmediato: el diseno de las chimeneas de las centrales termoelectricas que entraran en operacion durante los proximos anos, en el pais.

  8. Absorption spectra of AA-stacked graphite

    International Nuclear Information System (INIS)

    Chiu, C W; Lee, S H; Chen, S C; Lin, M F; Shyu, F L

    2010-01-01

    AA-stacked graphite shows strong anisotropy in geometric structures and velocity matrix elements. However, the absorption spectra are isotropic for the polarization vector on the graphene plane. The spectra exhibit one prominent plateau at middle energy and one shoulder structure at lower energy. These structures directly reflect the unique geometric and band structures and provide sufficient information for experimental fitting of the intralayer and interlayer atomic interactions. On the other hand, monolayer graphene shows a sharp absorption peak but no shoulder structure; AA-stacked bilayer graphene has two absorption peaks at middle energy and abruptly vanishes at lower energy. Furthermore, the isotropic features are expected to exist in other graphene-related systems. The calculated results and the predicted atomic interactions could be verified by optical measurements.

  9. Industrial stacks design; Diseno de chimeneas industriales

    Energy Technology Data Exchange (ETDEWEB)

    Cacheux, Luis [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1986-12-31

    The Instituto de Investigaciones Electricas (IIE) though its Civil Works Department, develops, under contract with CFE`s Gerencia de Proyectos Termoelectricos (Management of Fossil Power Plant Projects), a series of methods for the design of stacks, which pretends to solve the a present day problem: the stack design of the fossil power plants that will go into operation during the next coming years in the country. [Espanol] El Instituto de Investigaciones Electricas (IIE), a traves del Departamento de Ingenieria Civil, desarrolla, bajo contrato con la Gerencia de Proyectos Termoelectricos, de la Comision Federal de Electricidad (CFE), un conjunto de metodos para el diseno de chimeneas, con el que se pretende resolver un problema inmediato: el diseno de las chimeneas de las centrales termoelectricas que entraran en operacion durante los proximos anos, en el pais.

  10. 400 W High Temperature PEM Fuel Cell Stack Test

    DEFF Research Database (Denmark)

    Andreasen, Søren Juhl; Kær, Søren Knudsen

    2006-01-01

    This work demonstrates the operation of a 30 cell high temperature PEM (HTPEM) fuel cell stack. This prototype stack has been developed at the Institute of Energy Technology, Aalborg University, as a proof-of-concept for a low pressure cathode air cooled HTPEM stack. The membranes used are Celtec...

  11. Fault Diagnosis for Rotating Machinery Using Vibration Measurement Deep Statistical Feature Learning

    Directory of Open Access Journals (Sweden)

    Chuan Li

    2016-06-01

    Full Text Available Fault diagnosis is important for the maintenance of rotating machinery. The detection of faults and fault patterns is a challenging part of machinery fault diagnosis. To tackle this problem, a model for deep statistical feature learning from vibration measurements of rotating machinery is presented in this paper. Vibration sensor signals collected from rotating mechanical systems are represented in the time, frequency, and time-frequency domains, each of which is then used to produce a statistical feature set. For learning statistical features, real-value Gaussian-Bernoulli restricted Boltzmann machines (GRBMs are stacked to develop a Gaussian-Bernoulli deep Boltzmann machine (GDBM. The suggested approach is applied as a deep statistical feature learning tool for both gearbox and bearing systems. The fault classification performances in experiments using this approach are 95.17% for the gearbox, and 91.75% for the bearing system. The proposed approach is compared to such standard methods as a support vector machine, GRBM and a combination model. In experiments, the best fault classification rate was detected using the proposed model. The results show that deep learning with statistical feature extraction has an essential improvement potential for diagnosing rotating machinery faults.

  12. A Hybrid Feature Model and Deep-Learning-Based Bearing Fault Diagnosis

    Directory of Open Access Journals (Sweden)

    Muhammad Sohaib

    2017-12-01

    Full Text Available Bearing fault diagnosis is imperative for the maintenance, reliability, and durability of rotary machines. It can reduce economical losses by eliminating unexpected downtime in industry due to failure of rotary machines. Though widely investigated in the past couple of decades, continued advancement is still desirable to improve upon existing fault diagnosis techniques. Vibration acceleration signals collected from machine bearings exhibit nonstationary behavior due to variable working conditions and multiple fault severities. In the current work, a two-layered bearing fault diagnosis scheme is proposed for the identification of fault pattern and crack size for a given fault type. A hybrid feature pool is used in combination with sparse stacked autoencoder (SAE-based deep neural networks (DNNs to perform effective diagnosis of bearing faults of multiple severities. The hybrid feature pool can extract more discriminating information from the raw vibration signals, to overcome the nonstationary behavior of the signals caused by multiple crack sizes. More discriminating information helps the subsequent classifier to effectively classify data into the respective classes. The results indicate that the proposed scheme provides satisfactory performance in diagnosing bearing defects of multiple severities. Moreover, the results also demonstrate that the proposed model outperforms other state-of-the-art algorithms, i.e., support vector machines (SVMs and backpropagation neural networks (BPNNs.

  13. Fault Diagnosis for Rotating Machinery Using Vibration Measurement Deep Statistical Feature Learning.

    Science.gov (United States)

    Li, Chuan; Sánchez, René-Vinicio; Zurita, Grover; Cerrada, Mariela; Cabrera, Diego

    2016-06-17

    Fault diagnosis is important for the maintenance of rotating machinery. The detection of faults and fault patterns is a challenging part of machinery fault diagnosis. To tackle this problem, a model for deep statistical feature learning from vibration measurements of rotating machinery is presented in this paper. Vibration sensor signals collected from rotating mechanical systems are represented in the time, frequency, and time-frequency domains, each of which is then used to produce a statistical feature set. For learning statistical features, real-value Gaussian-Bernoulli restricted Boltzmann machines (GRBMs) are stacked to develop a Gaussian-Bernoulli deep Boltzmann machine (GDBM). The suggested approach is applied as a deep statistical feature learning tool for both gearbox and bearing systems. The fault classification performances in experiments using this approach are 95.17% for the gearbox, and 91.75% for the bearing system. The proposed approach is compared to such standard methods as a support vector machine, GRBM and a combination model. In experiments, the best fault classification rate was detected using the proposed model. The results show that deep learning with statistical feature extraction has an essential improvement potential for diagnosing rotating machinery faults.

  14. A Hybrid Feature Model and Deep-Learning-Based Bearing Fault Diagnosis.

    Science.gov (United States)

    Sohaib, Muhammad; Kim, Cheol-Hong; Kim, Jong-Myon

    2017-12-11

    Bearing fault diagnosis is imperative for the maintenance, reliability, and durability of rotary machines. It can reduce economical losses by eliminating unexpected downtime in industry due to failure of rotary machines. Though widely investigated in the past couple of decades, continued advancement is still desirable to improve upon existing fault diagnosis techniques. Vibration acceleration signals collected from machine bearings exhibit nonstationary behavior due to variable working conditions and multiple fault severities. In the current work, a two-layered bearing fault diagnosis scheme is proposed for the identification of fault pattern and crack size for a given fault type. A hybrid feature pool is used in combination with sparse stacked autoencoder (SAE)-based deep neural networks (DNNs) to perform effective diagnosis of bearing faults of multiple severities. The hybrid feature pool can extract more discriminating information from the raw vibration signals, to overcome the nonstationary behavior of the signals caused by multiple crack sizes. More discriminating information helps the subsequent classifier to effectively classify data into the respective classes. The results indicate that the proposed scheme provides satisfactory performance in diagnosing bearing defects of multiple severities. Moreover, the results also demonstrate that the proposed model outperforms other state-of-the-art algorithms, i.e., support vector machines (SVMs) and backpropagation neural networks (BPNNs).

  15. Imaging of Subsurface Faults using Refraction Migration with Fault Flooding

    KAUST Repository

    Metwally, Ahmed Mohsen Hassan

    2017-05-31

    We propose a novel method for imaging shallow faults by migration of transmitted refraction arrivals. The assumption is that there is a significant velocity contrast across the fault boundary that is underlain by a refracting interface. This procedure, denoted as refraction migration with fault flooding, largely overcomes the difficulty in imaging shallow faults with seismic surveys. Numerical results successfully validate this method on three synthetic examples and two field-data sets. The first field-data set is next to the Gulf of Aqaba and the second example is from a seismic profile recorded in Arizona. The faults detected by refraction migration in the Gulf of Aqaba data were in agreement with those indicated in a P-velocity tomogram. However, a new fault is detected at the end of the migration image that is not clearly seen in the traveltime tomogram. This result is similar to that for the Arizona data where the refraction image showed faults consistent with those seen in the P-velocity tomogram, except it also detected an antithetic fault at the end of the line. This fault cannot be clearly seen in the traveltime tomogram due to the limited ray coverage.

  16. Imaging of Subsurface Faults using Refraction Migration with Fault Flooding

    KAUST Repository

    Metwally, Ahmed Mohsen Hassan; Hanafy, Sherif; Guo, Bowen; Kosmicki, Maximillian Sunflower

    2017-01-01

    We propose a novel method for imaging shallow faults by migration of transmitted refraction arrivals. The assumption is that there is a significant velocity contrast across the fault boundary that is underlain by a refracting interface. This procedure, denoted as refraction migration with fault flooding, largely overcomes the difficulty in imaging shallow faults with seismic surveys. Numerical results successfully validate this method on three synthetic examples and two field-data sets. The first field-data set is next to the Gulf of Aqaba and the second example is from a seismic profile recorded in Arizona. The faults detected by refraction migration in the Gulf of Aqaba data were in agreement with those indicated in a P-velocity tomogram. However, a new fault is detected at the end of the migration image that is not clearly seen in the traveltime tomogram. This result is similar to that for the Arizona data where the refraction image showed faults consistent with those seen in the P-velocity tomogram, except it also detected an antithetic fault at the end of the line. This fault cannot be clearly seen in the traveltime tomogram due to the limited ray coverage.

  17. A Late Pleistocene sea level stack

    OpenAIRE

    Spratt Rachel M; Lisiecki Lorraine E

    2016-01-01

    Late Pleistocene sea level has been reconstructed from ocean sediment core data using a wide variety of proxies and models. However, the accuracy of individual reconstructions is limited by measurement error, local variations in salinity and temperature, and assumptions particular to each technique. Here we present a sea level stack (average) which increases the signal-to-noise ratio of individual reconstructions. Specifically, we perform principal componen...

  18. CAM and stack air sampler design guide

    International Nuclear Information System (INIS)

    Phillips, T.D.

    1994-01-01

    About 128 air samplers and CAMs presently in service to detect and document potential radioactive release from 'H' and 'F' area tank farm ventilation stacks are scheduled for replacement and/or upgrade by Projects S-5764, S-2081, S-3603, and S-4516. The seven CAMs scheduled to be upgraded by Project S-4516 during 1995 are expected to provide valuable experience for the three remaining projects. The attached document provides design guidance for the standardized High Level Waste air sampling system

  19. Extended Life PZT Stack Test Fixture

    Science.gov (United States)

    Badescu, Mircea; Sherrit, S.; Bao, X.; Aldrich, J.; Bar-Cohen, Y.; Jones, C.

    2009-01-01

    Piezoelectric stacks are being sought to be used as actuators for precision positioning and deployment of mechanisms in future planetary missions. Beside the requirement for very high operation reliability, these actuators are required for operation at space environments that are considered harsh compared to normal terrestrial conditions.These environmental conditions include low and high temperatures and vacuum or high pressure. Additionally, the stacks are subjected to high stress and in some applications need to operate with a very long lifetime durability.Many of these requirements are beyond the current industry design margins for nominal terrestrial applications. In order to investigate some of the properties that will indicate the durability of such actuators and their limitations we have developed a new type of test fixture that can be easily integrated in various test chambers for simulating environmental conditions, can provide access for multiple measurements while being exposed to adjustable stress levels. We designed and built two test fixtures and these fixtures were made to be adjustable for testing stacks with different dimensions and can be easily used in small or large numbers. The properties that were measured using these fixtures include impedance, capacitance, dielectric loss factor, leakage current, displacement, breakdown voltage, and lifetime performance. The fixtures characteristics and the test capabilities are presented in this paper.

  20. Electrochemical Detection in Stacked Paper Networks.

    Science.gov (United States)

    Liu, Xiyuan; Lillehoj, Peter B

    2015-08-01

    Paper-based electrochemical biosensors are a promising technology that enables rapid, quantitative measurements on an inexpensive platform. However, the control of liquids in paper networks is generally limited to a single sample delivery step. Here, we propose a simple method to automate the loading and delivery of liquid samples to sensing electrodes on paper networks by stacking multiple layers of paper. Using these stacked paper devices (SPDs), we demonstrate a unique strategy to fully immerse planar electrodes by aqueous liquids via capillary flow. Amperometric measurements of xanthine oxidase revealed that electrochemical sensors on four-layer SPDs generated detection signals up to 75% higher compared with those on single-layer paper devices. Furthermore, measurements could be performed with minimal user involvement and completed within 30 min. Due to its simplicity, enhanced automation, and capability for quantitative measurements, stacked paper electrochemical biosensors can be useful tools for point-of-care testing in resource-limited settings. © 2015 Society for Laboratory Automation and Screening.

  1. The use of Stress Tensor Discriminator Faults in separating heterogeneous fault-slip data with best-fit stress inversion methods. II. Compressional stress regimes

    Science.gov (United States)

    Tranos, Markos D.

    2018-02-01

    Synthetic heterogeneous fault-slip data as driven by Andersonian compressional stress tensors were used to examine the efficiency of best-fit stress inversion methods in separating them. Heterogeneous fault-slip data are separated only if (a) they have been driven by stress tensors defining 'hybrid' compression (R constitute a necessary discriminatory tool for the establishment and comparison of two compressional stress tensors determined by a best-fit stress inversion method. The best-fit stress inversion methods are not able to determine more than one 'real' compressional stress tensor, as far as the thrust stacking in an orogeny is concerned. They can only possibly discern stress differences in the late-orogenic faulting processes, but not between the main- and late-orogenic stages.

  2. Performance of a methane-fueled single-cell SOFC stack at various levels of fuel utilization

    International Nuclear Information System (INIS)

    Ahmed, K.; Bolden, R.; Ramprakash and Foger, K.

    1998-01-01

    Fuel-gas mixtures representing 10 to 85% utilization of a methane-steam mixture at S/C=2 were fed to a single cell stack with a Ni-based anode at 875 deg C. Cell voltage and power output were recorded at current densities of 50 to 350 mA/cm 2 . The accompanying anode off-gas composition at some of these conditions were measured using on-line gas chromatograph and compared with the compositions predicted by a thermodynamic model based on the assumption of no carbon formation. Electrical losses were measured at a chosen current density at various levels of fuel utilization by the galvanostatic current-interruption technique. Cell voltage stability was monitored for up to 1000 h at two levels of fuel utilization. The stack performance was simulated using a mathematical model of the stack; the simulations were compared with the stack test data. Copyright (1998) Australasian Ceramic Society

  3. Geology Structure Identification Using Pre-Stack Depth Migration (PSDM Method of Tomography Result in North West Java Basin

    Directory of Open Access Journals (Sweden)

    Sudra Irawan

    2017-06-01

    Full Text Available North West Java Basin is a tertiary sedimentary basin which is located in the right of the western part of the Java island. North West Java Basin is geodynamic where currently located at the rear position of the path of the volcanic arc of Java that is the result of the India-Australia plate subduction to the south towards the Eurasian plate (Explanation of Sunda in the north. Geology structure observation is difficult to be conducted at Quaternary volcanicfield due to the classical problem at tropical region. In the study interpretation of fault structures can be done on a cross-section of Pre-Stack Depth Migration (PSDM used prayer namely Hardware Key Device, ie Central Processing Unit: RedHat Enterprise Linux AS 5.0, prayer Monitor 24-inch pieces, Server: SGI altix 450/SuSe Linux Enterprise Server 9.0, 32 GB, 32 X 2,6 GHz Procesor, network: Gigabyte 1 Gb/s, and the software used is paradigm, product: Seismic Processing and Imaging. The third fault obtained in this study in accordance with the geological information derived from previous research conducted by geologists. The second general direction is northwest-southeast direction represented by Baribis fault, fault-fault in the Valley Cimandiri and Gunung Walat. This direction is often known as the directions Meratus (Meratus Trend. Meratus directions interpreted as directions that follow the pattern of continuous arc Cretaceous age to Meratus in Kalimantan.

  4. Wilshire fault: Earthquakes in Hollywood?

    Science.gov (United States)

    Hummon, Cheryl; Schneider, Craig L.; Yeats, Robert S.; Dolan, James F.; Sieh, Kerry E.; Huftile, Gary J.

    1994-04-01

    The Wilshire fault is a potentially seismogenic, blind thrust fault inferred to underlie and cause the Wilshire arch, a Quaternary fold in the Hollywood area, just west of downtown Los Angeles, California. Two inverse models, based on the Wilshire arch, allow us to estimate the location and slip rate of the Wilshire fault, which may be illuminated by a zone of microearthquakes. A fault-bend fold model indicates a reverse-slip rate of 1.5-1.9 mm/yr, whereas a three-dimensional elastic-dislocation model indicates a right-reverse slip rate of 2.6-3.2 mm/yr. The Wilshire fault is a previously unrecognized seismic hazard directly beneath Hollywood and Beverly Hills, distinct from the faults under the nearby Santa Monica Mountains.

  5. What is Fault Tolerant Control

    DEFF Research Database (Denmark)

    Blanke, Mogens; Frei, C. W.; Kraus, K.

    2000-01-01

    Faults in automated processes will often cause undesired reactions and shut-down of a controlled plant, and the consequences could be damage to the plant, to personnel or the environment. Fault-tolerant control is the synonym for a set of recent techniques that were developed to increase plant...... availability and reduce the risk of safety hazards. Its aim is to prevent that simple faults develop into serious failure. Fault-tolerant control merges several disciplines to achieve this goal, including on-line fault diagnosis, automatic condition assessment and calculation of remedial actions when a fault...... is detected. The envelope of the possible remedial actions is wide. This paper introduces tools to analyze and explore structure and other fundamental properties of an automated system such that any redundancy in the process can be fully utilized to enhance safety and a availability....

  6. Direct fault dating trials at the Aespoe Hard Rock Laboratory

    International Nuclear Information System (INIS)

    Maddock, R.H.; Hailwood, E.A.

    1993-10-01

    Over seventy rock samples were collected from fault and fracture zones in the Aespoe Hard Rock Laboratory tunnel for a study of direct fault dating techniques. Following microstructural and mineralogical analysis, isotopic, palaeomagnetic and electron spin resonance (ESR) methods were employed in an attempt to determine the age of the most recent movements on the sampled faults. The larger fracture zones contain faultrock assemblages and microstructures which are consistent with a prolonged and polyphase movement history, although the cumulative displacements involved formation of fault gouge cemented by authigenic 'illite'. Dating studies were targeted particularly at the gouge but also at older fault rock and vein phases. ESR dating of quartz graines, separated from gouge from fracture zones NE-4 and NE-3, strongly indicates that the ESR signals have not been reset by fault movements for a minimum time period of several hundred thousand to one million years. Palaeomagnetic dating of gouge from fracture zone NE-4 shows that a stable component of magnetisation overlaps both Precambrian and Permo-Triassic parts of the apparent polar wander curve. The younger age of magnetisation is preferred on geological grounds and by comparison with the isotopic dating results. The magnetisation may correspond to a diagenetic event following fault movement. Palaeomagnetic ages determined on countryrock and epidote vein samples are largely consistent with independent age constraints. K-Ar dating of clay fractions (<2 to <0.05μm) separated from gouge from four faults, including fracture zones NE-4 and NE-3, gave model ages in the range 706-301Ma. Accounting for the effects of contamination by potassium-bearing porphyroclasts, it is likely that authigenic 'illite' was formed at least 250 million years ago, after the most recent significant fault movements. 100 refs., 60 figs., 26 tabs

  7. Spatial arrangement of faults and opening-mode fractures

    Science.gov (United States)

    Laubach, S. E.; Lamarche, J.; Gauthier, B. D. M.; Dunne, W. M.; Sanderson, David J.

    2018-03-01

    Spatial arrangement is a fundamental characteristic of fracture arrays. The pattern of fault and opening-mode fracture positions in space defines structural heterogeneity and anisotropy in a rock volume, governs how faults and fractures affect fluid flow, and impacts our understanding of the initiation, propagation and interactions during the formation of fracture patterns. This special issue highlights recent progress with respect to characterizing and understanding the spatial arrangements of fault and fracture patterns, providing examples over a wide range of scales and structural settings. Five papers describe new methods and improvements of existing techniques to quantify spatial arrangement. One study unravels the time evolution of opening-mode fracture spatial arrangement, which are data needed to compare natural patterns with progressive fracture growth in kinematic and mechanical models. Three papers investigate the role of evolving diagenesis in localizing fractures by mechanical stratigraphy and nine discuss opening-mode fracture spatial arrangement. Two papers show the relevance of complex cluster patterns to unconventional reservoirs through examples of fractures in tight gas sandstone horizontal wells, and a study of fracture arrangement in shale. Four papers demonstrate the roles of folds in fracture localization and the development spatial patterns. One paper models along-fault friction and fluid pressure and their effects on fault-related fracture arrangement. Contributions address deformation band patterns in carbonate rocks and fault size and arrangement above a detachment fault. Three papers describe fault and fracture arrangements in basement terrains, and three document fracture patterns in shale. This collection of papers points toward improvement in field methods, continuing improvements in computer-based data analysis and creation of synthetic fracture patterns, and opportunities for further understanding fault and fracture attributes in

  8. Guanine base stacking in G-quadruplex nucleic acids

    Science.gov (United States)

    Lech, Christopher Jacques; Heddi, Brahim; Phan, Anh Tuân

    2013-01-01

    G-quadruplexes constitute a class of nucleic acid structures defined by stacked guanine tetrads (or G-tetrads) with guanine bases from neighboring tetrads stacking with one another within the G-tetrad core. Individual G-quadruplexes can also stack with one another at their G-tetrad interface leading to higher-order structures as observed in telomeric repeat-containing DNA and RNA. In this study, we investigate how guanine base stacking influences the stability of G-quadruplexes and their stacked higher-order structures. A structural survey of the Protein Data Bank is conducted to characterize experimentally observed guanine base stacking geometries within the core of G-quadruplexes and at the interface between stacked G-quadruplex structures. We couple this survey with a systematic computational examination of stacked G-tetrad energy landscapes using quantum mechanical computations. Energy calculations of stacked G-tetrads reveal large energy differences of up to 12 kcal/mol between experimentally observed geometries at the interface of stacked G-quadruplexes. Energy landscapes are also computed using an AMBER molecular mechanics description of stacking energy and are shown to agree quite well with quantum mechanical calculated landscapes. Molecular dynamics simulations provide a structural explanation for the experimentally observed preference of parallel G-quadruplexes to stack in a 5′–5′ manner based on different accessible tetrad stacking modes at the stacking interfaces of 5′–5′ and 3′–3′ stacked G-quadruplexes. PMID:23268444

  9. Continental deformation accommodated by non-rigid passive bookshelf faulting: An example from the Cenozoic tectonic development of northern Tibet

    Science.gov (United States)

    Zuza, Andrew V.; Yin, An

    2016-05-01

    Collision-induced continental deformation commonly involves complex interactions between strike-slip faulting and off-fault deformation, yet this relationship has rarely been quantified. In northern Tibet, Cenozoic deformation is expressed by the development of the > 1000-km-long east-striking left-slip Kunlun, Qinling, and Haiyuan faults. Each have a maximum slip in the central fault segment exceeding 10s to ~ 100 km but a much smaller slip magnitude (~bookshelf-fault model for the Cenozoic tectonic development of northern Tibet. Our model, quantitatively relating discrete left-slip faulting to distributed off-fault deformation during regional clockwise rotation, explains several puzzling features, including the: (1) clockwise rotation of east-striking left-slip faults against the northeast-striking left-slip Altyn Tagh fault along the northwestern margin of the Tibetan Plateau, (2) alternating fault-parallel extension and shortening in the off-fault regions, and (3) eastward-tapering map-view geometries of the Qimen Tagh, Qaidam, and Qilian Shan thrust belts that link with the three major left-slip faults in northern Tibet. We refer to this specific non-rigid bookshelf-fault system as a passive bookshelf-fault system because the rotating bookshelf panels are detached from the rigid bounding domains. As a consequence, the wallrock of the strike-slip faults deforms to accommodate both the clockwise rotation of the left-slip faults and off-fault strain that arises at the fault ends. An important implication of our model is that the style and magnitude of Cenozoic deformation in northern Tibet vary considerably in the east-west direction. Thus, any single north-south cross section and its kinematic reconstruction through the region do not properly quantify the complex deformational processes of plateau formation.

  10. Formation of incoherent deformation twin boundaries in a coarse-grained Al-7Mg alloy

    Science.gov (United States)

    Jin, S. B.; Zhang, K.; Bjørge, R.; Tao, N. R.; Marthinsen, K.; Lu, K.; Li, Y. J.

    2015-08-01

    Deformation twinning has rarely been observed in coarse grained Al and its alloys except under some extreme conditions such as ultrahigh deformation strain or strain rates. Here, we report that a significant amount of Σ3 deformation twins could be generated in a coarse-grained Al-7 Mg alloy by dynamic plastic deformation (DPD). A systematic investigation of the Σ3 boundaries shows that they are Σ3{112} type incoherent twin boundaries (ITBs). These ITBs have formed by gradual evolution from copious low-angle deformation bands through -twist Σ boundaries by lattice rotation. These findings provide an approach to generate deformation twin boundaries in high stacking fault energy metallic alloys. It is suggested that high solution content of Mg in the alloy and the special deformation mode of DPD played an important role in formation of the Σ and ITBs.

  11. Advanced cloud fault tolerance system

    Science.gov (United States)

    Sumangali, K.; Benny, Niketa

    2017-11-01

    Cloud computing has become a prevalent on-demand service on the internet to store, manage and process data. A pitfall that accompanies cloud computing is the failures that can be encountered in the cloud. To overcome these failures, we require a fault tolerance mechanism to abstract faults from users. We have proposed a fault tolerant architecture, which is a combination of proactive and reactive fault tolerance. This architecture essentially increases the reliability and the availability of the cloud. In the future, we would like to compare evaluations of our proposed architecture with existing architectures and further improve it.

  12. Final Technical Report: PV Fault Detection Tool.

    Energy Technology Data Exchange (ETDEWEB)

    King, Bruce Hardison [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jones, Christian Birk [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-12-01

    The PV Fault Detection Tool project plans to demonstrate that the FDT can (a) detect catastrophic and degradation faults and (b) identify the type of fault. This will be accomplished by collecting fault signatures using different instruments and integrating this information to establish a logical controller for detecting, diagnosing and classifying each fault.

  13. Fault current limiter

    Science.gov (United States)

    Darmann, Francis Anthony

    2013-10-08

    A fault current limiter (FCL) includes a series of high permeability posts for collectively define a core for the FCL. A DC coil, for the purposes of saturating a portion of the high permeability posts, surrounds the complete structure outside of an enclosure in the form of a vessel. The vessel contains a dielectric insulation medium. AC coils, for transporting AC current, are wound on insulating formers and electrically interconnected to each other in a manner such that the senses of the magnetic field produced by each AC coil in the corresponding high permeability core are opposing. There are insulation barriers between phases to improve dielectric withstand properties of the dielectric medium.

  14. Dynamic Model of High Temperature PEM Fuel Cell Stack Temperature

    DEFF Research Database (Denmark)

    Andreasen, Søren Juhl; Kær, Søren Knudsen

    2007-01-01

    cathode air cooled 30 cell HTPEM fuel cell stack developed at the Institute of Energy Technology at Aalborg University. This fuel cell stack uses PEMEAS Celtec P-1000 membranes, runs on pure hydrogen in a dead end anode configuration with a purge valve. The cooling of the stack is managed by running......The present work involves the development of a model for predicting the dynamic temperature of a high temperature PEM (HTPEM) fuel cell stack. The model is developed to test different thermal control strategies before implementing them in the actual system. The test system consists of a prototype...... the stack at a high stoichiometric air flow. This is possible because of the PBI fuel cell membranes used, and the very low pressure drop in the stack. The model consists of a discrete thermal model dividing the stack into three parts: inlet, middle and end and predicting the temperatures in these three...

  15. Fault Management Design Strategies

    Science.gov (United States)

    Day, John C.; Johnson, Stephen B.

    2014-01-01

    Development of dependable systems relies on the ability of the system to determine and respond to off-nominal system behavior. Specification and development of these fault management capabilities must be done in a structured and principled manner to improve our understanding of these systems, and to make significant gains in dependability (safety, reliability and availability). Prior work has described a fundamental taxonomy and theory of System Health Management (SHM), and of its operational subset, Fault Management (FM). This conceptual foundation provides a basis to develop framework to design and implement FM design strategies that protect mission objectives and account for system design limitations. Selection of an SHM strategy has implications for the functions required to perform the strategy, and it places constraints on the set of possible design solutions. The framework developed in this paper provides a rigorous and principled approach to classifying SHM strategies, as well as methods for determination and implementation of SHM strategies. An illustrative example is used to describe the application of the framework and the resulting benefits to system and FM design and dependability.

  16. Fracture Modes and Identification of Fault Zones in Wenchuan Earthquake Fault Scientific Drilling Boreholes

    Science.gov (United States)

    Deng, C.; Pan, H.; Zhao, P.; Qin, R.; Peng, L.

    2017-12-01

    After suffering from the disaster of Wenchuan earthquake on May 12th, 2008, scientists are eager to figure out the structure of formation, the geodynamic processes of faults and the mechanism of earthquake in Wenchuan by drilling five holes into the Yingxiu-Beichuan fault zone and Anxian-Guanxian fault zone. Fractures identification and in-situ stress determination can provide abundant information for formation evaluation and earthquake study. This study describe all the fracture modes in the five boreholes on the basis of cores and image logs, and summarize the response characteristics of fractures in conventional logs. The results indicate that the WFSD boreholes encounter enormous fractures, including natural fractures and induced fractures, and high dip-angle conductive fractures are the most common fractures. The maximum horizontal stress trends along the borehole are deduced as NWW-SEE according to orientations of borehole breakouts and drilling-induced fractures, which is nearly parallel to the strikes of the younger natural fracture sets. Minor positive deviations of AC (acoustic log) and negative deviation of DEN (density log) demonstrate their responses to fracture, followed by CNL (neutron log), resistivity logs and GR (gamma ray log) at different extent of intensity. Besides, considering the fact that the reliable methods for identifying fracture zone, like seismic, core recovery and image logs, can often be hampered by their high cost and limited application, this study propose a method by using conventional logs, which are low-cost and available in even old wells. We employ wavelet decomposition to extract the high frequency information of conventional logs and reconstruction a new log in special format of enhance fracture responses and eliminate nonfracture influence. Results reveal that the new log shows obvious deviations in fault zones, which confirm the potential of conventional logs in fracture zone identification.

  17. Formation and characterization of Y : 247 film through spray ...

    Indian Academy of Sciences (India)

    Unknown

    gions (< 50 Å) of minority Y : 124 phase and stacking faults capable of ... critical current density (Jc) for Y : 247 films is ~ 103 A/cm2, and with silver ..... biphasic. As a result of decomposition, Y : 247 may be partially converted into Y : 124.

  18. Accelerometer having integral fault null

    Science.gov (United States)

    Bozeman, Richard J., Jr.

    1995-08-01

    An improved accelerometer is introduced. It comprises a transducer responsive to vibration in machinery which produces an electrical signal related to the magnitude and frequency of the vibration; and a decoding circuit responsive to the transducer signal which produces a first fault signal to produce a second fault signal in which ground shift effects are nullified.

  19. NSF tandem stack support structure deflection characteristics

    International Nuclear Information System (INIS)

    Cook, J.

    1979-12-01

    Results are reported of load tests carried out on the glass legs of the insulating stack of the 30 MV tandem Van de Graaff accelerator now under construction at Daresbury Laboratory. The tests to investigate the vulnerability of the legs when subjected to tensile stresses were designed to; establish the angle of rotation of the pads from which the stresses in the glass legs may be calculated, proof-test the structure and at the same time reveal any asymmetry in pad rotations or deflections, and to confirm the validity of the computer design analysis. (UK)

  20. Compliant Glass Seals for SOFC Stacks

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Yeong -Shyung [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Choi, Jung-Pyung [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Xu, Wei [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stephens, Elizabeth V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Koeppel, Brian J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stevenson, Jeffry W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lara-Curzio, Edgar [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-04-30

    This report summarizes results from experimental and modeling studies performed by participants in the Solid-State Energy Conversion Alliance (SECA) Core Technology Program, which indicate that compliant glass-based seals offer a number of potential advantages over conventional seals based on de-vitrifying glasses, including reduced stresses during stack operation and thermal cycling, and the ability to heal micro-damage induced during thermal cycling. The properties and composition of glasses developed and/or investigated in these studies are reported, along with results from long-term (up to 5,800h) evaluations of seals based on a compliant glass containing ceramic particles or ceramic fibers.

  1. Improved Direct Methanol Fuel Cell Stack

    Science.gov (United States)

    Wilson, Mahlon S.; Ramsey, John C.

    2005-03-08

    A stack of direct methanol fuel cells exhibiting a circular footprint. A cathode and anode manifold, tie-bolt penetrations and tie-bolts are located within the circular footprint. Each fuel cell uses two graphite-based plates. One plate includes a cathode active area that is defined by serpentine channels connecting the inlet and outlet cathode manifold. The other plate includes an anode active area defined by serpentine channels connecting the inlet and outlet of the anode manifold, where the serpentine channels of the anode are orthogonal to the serpentine channels of the cathode. Located between the two plates is the fuel cell active region.

  2. Rapid subsidence and stacked Gilbert-type fan deltas, Pliocene Loreto basin, Baja California Sur, Mexico

    Science.gov (United States)

    Dorsey, Rebecca J.; Umhoefer, Paul J.; Renne, Paul R.

    1995-08-01

    Pliocene nonmarine to marine sedimentary rocks exposed in the Loreto basin, Baja California Sur, provide a record of syntectonic subsidence and sedimentation in a transform-rift basin that developed along the western margin of the Gulf of California. A thick sequence of twelve Gilbert-type fan deltas, having a total measured thickness of about 615 m, accumulated near the fault-bounded southwestern margin of this basin. Based on stratal geometries and lithofacies associations, sedimentary rocks are divided into Gilbert-delta topset, foreset and bottomset strata, shell beds and background shallow-marine shelf deposits. Topset strata of each Gilbert-type delta cycle are capped by laterally persistent molluscan shell beds containing diverse assemblages of bivalves, pectens, oysters, gastropods and echinoids. These shell beds are interpreted to be condensed intervals that record sediment starvation during abandonment of the fan-delta plain. Delta abandonment may have been caused by large episodic faulting events, which submerged each pre-existing fan-delta plain, substantially slowed detrital input by drowning of alluvial feeder channels, and created new accommodation space for each new Gilbert-type fan delta. Alternatively, it is possible that delta-plain abandonment was caused by upstream avulsions and autocyclic lateral switching of fan-delta lobes during relatively uniform rates of slip along the basin-bounding fault. Two contrasting, plausible basin models are proposed for the Loreto basin: (1) asymmetric subsidence along a high-angle oblique-slip normal fault, producing a classic half-graben basin geometry with vertically stacked Gilbert-type fan deltas; or (2) lateral stacking and horizontal displacement of strata away from a relatively fixed depocenter due to fault movement in the releasing bend of a listric strike-slip fault. We favor the first model because field relations and simple geometric constraints suggest that most of the total measured section

  3. Landforms along transverse faults parallel to axial zone of folded ...

    Indian Academy of Sciences (India)

    Himalaya, along the Kali River valley, is defined by folded hanging wall ... role of transverse fault tectonics in the formation of the curvature cannot be ruled out. 1. .... Piedmont surface is made up of gravelliferous and ... made to compute the wedge failure analysis (Hoek .... (∼T2) is at the elevation of ∼272 m asl measured.

  4. Assemblage of strike-slip faults and tectonic extension and ...

    Indian Academy of Sciences (India)

    12

    the formation, evolution and distribution of these strike-slip faults have important. 80 ...... function of coal-derived gas study for natural gas industry development in China; .... Bohai-Zhangjiakou seismotectonic zone based on 3D visco-elastic ...

  5. Faults and ridges - Historical development in Tempe Terra and Ulysses Patera regions of Mars

    International Nuclear Information System (INIS)

    Scott, D.H.; Dohm, J.M.

    1990-01-01

    Tempe Terra and the area north of Ulysses Patera are selected to demonstrate the various stages of faulting and ridge development in local areas. This work is accomplished by using Viking photomosaics to determine crosscutting relations of structures as well as their morphology and trend orientations. Results show that from the Early Noachian through the Early Amazonian Epochs, at least eight episodes of faulting occurred at Tempe Terra and six at Ulysses Patera. Tectonic activity at Tempe Terra was expressed mainly by densely spaced faults along the northeast extension of the Tharsis rise; faulting culminated in the Middle and Late Noachian and was superseded by transverse fault systems from the Alba Patera region during the Hesperian. Ridge formation, however, was most active in the Early Hesperian. At Ulysses Patera, an early history of tectonism is recorded by complex arrays of faults in a relatively small area of Noachian rocks. 14 refs

  6. Middle Miocene E-W tectonic horst structure of Crete through extensional detachment faults

    International Nuclear Information System (INIS)

    Papanikolaou, D; Vassilakis, E

    2008-01-01

    Two east-west trending extensional detachment faults have been recognized in Crete, one with top-to-the-north motion of the hanging wall toward the Cretan Sea and one with top-to-the-south motion of the hanging wall toward the Libyan Sea. The east-west trending zone between these two detachment faults, which forms their common footwall, comprises a tectonic horst formed during Middle Miocene slip on the detachment faults. The detachment faults disrupt the overall tectono-stratigraphic succession of Crete and are localized along pre-existing thrust faults and along particular portions of the stratigraphic sequence, including the transition between the Permo-Triassic Tyros Beds and the base of the Upper Triassic-Eocene carbonate platform of the Tripolis nappe. By recognizing several different tectono-stratigraphic formations within what is generally termed the 'phyllite-quartzite', it is possible to distinguish these extensional detachment faults from thrust faults and minor discontinuities in the sequence. The deformation history of units within Crete can be summarized as: (i) compressional deformation producing arc-parallel east-west trending south-directed thrust faults in Oligocene to Early Miocene time (ii) extensional deformation along arc-parallel, east-west trending detachment faults in Middle Miocene time, with hanging wall motion to the north and south; (iii) Late Miocene-Quaternary extensional deformation along high-angle normal and oblique normal faults that disrupt the older arc-parallel structures

  7. Fault isolatability conditions for linear systems

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, Henrik

    2006-01-01

    In this paper, we shall show that an unlimited number of additive single faults can be isolated under mild conditions if a general isolation scheme is applied. Multiple faults are also covered. The approach is algebraic and is based on a set representation of faults, where all faults within a set...... the faults have occurred. The last step is a fault isolation (FI) of the faults occurring in a specific fault set, i.e. equivalent with the standard FI step. A simple example demonstrates how to turn the algebraic necessary and sufficient conditions into explicit algorithms for designing filter banks, which...

  8. ESR dating of the fault rocks

    International Nuclear Information System (INIS)

    Lee, Hee Kwon

    2005-01-01

    We carried out ESR dating of fault rocks collected near the nuclear reactor. The Upcheon fault zone is exposed close to the Ulzin nuclear reactor. The space-time pattern of fault activity on the Upcheon fault deduced from ESR dating of fault gouge can be summarised as follows : this fault zone was reactivated between fault breccia derived from Cretaceous sandstone and tertiary volcanic sedimentary rocks about 2 Ma, 1.5 Ma and 1 Ma ago. After those movements, the Upcheon fault was reactivated between Cretaceous sandstone and fault breccia zone about 800 ka ago. This fault zone was reactivated again between fault breccia derived form Cretaceous sandstone and Tertiary volcanic sedimentary rocks about 650 ka and after 125 ka ago. These data suggest that the long-term(200-500 k.y.) cyclic fault activity of the Upcheon fault zone continued into the Pleistocene. In the Ulzin area, ESR dates from the NW and EW trend faults range from 800 ka to 600 ka NE and EW trend faults were reactivated about between 200 ka and 300 ka ago. On the other hand, ESR date of the NS trend fault is about 400 ka and 50 ka. Results of this research suggest the fault activity near the Ulzin nuclear reactor fault activity continued into the Pleistocene. One ESR date near the Youngkwang nuclear reactor is 200 ka

  9. In-stack condensible particulate matter measurement and permitting issues

    International Nuclear Information System (INIS)

    Corio, L.A.; Sherwell, J.

    1997-01-01

    Based on the results of recent epidemiological studies and assessments of the causes of visibility degradation, EPA is proposing to regulate PM2.5 emissions. PM can be classified as either filterable or condensible PM. Condensible PM includes sulfates, such as sulfuric acid. Sulfates typically account for at least half of the total dry fine PM mass in the atmosphere. Power plant SO x -based emissions make a significant contribution to ambient fine PM levels in the eastern US. Although much of this mass is derived from secondary chemical reactions in the atmosphere, a portion of this sulfate is emitted directly from stacks as condensible PM. The potential condensible PM fraction associated with coal-burning boiler emissions is somewhat uncertain. The characterization of PM emissions from these sources has been, until recently, based on in-stack filterable PM measurements only. To determine the relative magnitude of condensible PM emissions and better understand condensible PM measurement issues, a review and analysis of actual EPA Method 202 results and state-developed hybrid condensible PM methods were conducted. A review of available Method 202 results for several coal-burning boilers showed that the condensible PM, on average, comprises 60% of the total PM10. A review of recent results for state-developed measurement methods for condensible PM for numerous coal-burning boilers indicated that condensible PM accounted for, on average, approximately 49% of total PM. Caution should be exercised in the use of these results because of the seemingly unresolved issue of artifact formation, which may bias the Method 202 and state-developed methods results on the high side. Condensible PM10 measurement results and issues, and potential ramifications of including condensible PM10 emissions in the PSD permit review process are discussed. Selected power plants in Maryland are discussed as examples

  10. Alteration of fault rocks by CO2-bearing fluids with implications for sequestration

    Science.gov (United States)

    Luetkemeyer, P. B.; Kirschner, D. L.; Solum, J. G.; Naruk, S.

    2011-12-01

    Carbonates and sulfates commonly occur as primary (diagenetic) pore cements and secondary fluid-mobilized veins within fault zones. Stable isotope analyses of calcite, formation fluid, and fault zone fluids can help elucidate the carbon sources and the extent of fluid-rock interaction within a particular reservoir. Introduction of CO2 bearing fluids into a reservoir/fault system can profoundly affect the overall fluid chemistry of the reservoir/fault system and may lead to the enhancement or degradation of porosity within the fault zone. The extent of precipitation and/or dissolution of minerals within a fault zone can ultimately influence the sealing properties of a fault. The Colorado Plateau contains a number of large carbon dioxide reservoirs some of which leak and some of which do not. Several normal faults within the Paradox Basin (SE Utah) dissect the Green River anticline giving rise to a series of footwall reservoirs with fault-dependent columns. Numerous CO2-charged springs and geysers are associated with these faults. This study seeks to identify regional sources and subsurface migration of CO2 to these reservoirs and the effect(s) faults have on trap performance. Data provided in this study include mineralogical, elemental, and stable isotope data for fault rocks, host rocks, and carbonate veins that come from two localities along one fault that locally sealed CO2. This fault is just tens of meters away from another normal fault that has leaked CO2-charged waters to the land surface for thousands of years. These analyses have been used to determine the source of carbon isotopes from sedimentary derived carbon and deeply sourced CO2. XRF and XRD data taken from several transects across the normal faults are consistent with mechanical mixing and fluid-assisted mass transfer processes within the fault zone. δ13C range from -6% to +10% (PDB); δ18O values range from +15% to +24% (VSMOW). Geochemical modeling software is used to model the alteration

  11. Fault distribution in the Precambrian basement of South Norway

    Science.gov (United States)

    Gabrielsen, Roy H.; Nystuen, Johan Petter; Olesen, Odleiv

    2018-03-01

    Mapping of the structural pattern by remote sensing methods (Landsat, SPOT, aerial photography, potential field data) and field study of selected structural elements shows that the cratonic basement of South Norway is strongly affected by a regular lineament pattern that encompasses fault swarms of different orientation, age, style, attitude and frequency. Albeit counting numerous fault and fracture populations, the faults are not evenly distributed and N-S to NNE-SSW/NNW-SSE and NE-SE/ENE-WSW-systems are spatially dominant. N-S to NNW-SSE structures can be traced underneath the Caledonian nappes to the Western Gneiss Region in western and central South Norway, emphasizing their ancient roots. Dyke swarms of different ages are found within most of these zones. Also, the Østfold, Oslo-Trondheim and the Mandal-Molde lineament zones coincide with trends of Sveconorwegian post-collision granites. We conclude that the N-S-trend includes the most ancient structural elements, and that the trend can be traced back to the Proterozoic (Svecofennian and Sveconorwegian) orogenic events. Some of the faults may have been active in Neoproterozoic times as marginal faults of rift basins at the western margin of Baltica. Remnants of such fault activity have survived in the cores of many of the faults belonging to this system. The ancient systems of lineaments were passively overridden by the Caledonian fold-and-thrust system and remained mostly, but note entirely inactive throughout the Sub-Cambrian peneplanation and the Caledonian orogenic collapse in the Silurian-Devonian. The system was reactivated in extension from Carboniferous times, particularly in the Permian with the formation of the Oslo Rift and parts of it remain active to the Present, albeit by decreasing extension and fault activity.

  12. Seismic Imaging of the West Napa Fault in Napa, California

    Science.gov (United States)

    Goldman, M.; Catchings, R.; Chan, J. H.; Sickler, R. R.; Nevitt, J. M.; Criley, C.

    2017-12-01

    In October 2016, we acquired high-resolution P- and S-wave seismic data along a 120-m-long, SW-NE-trending profile in Napa, California. Our seismic survey was designed to image a strand of the West Napa Fault Zone (WNFZ), which ruptured during the 24 August 2014 Mw 6.0 South Napa Earthquake. We separately acquired P- and S-wave data at every station using multiple hammer hits, which were edited and stacked into individual shot gathers in the lab. Each shot was co-located with and recorded by 118 P-wave (40-Hz) geophones, spaced at 1 m, and by 180 S-wave (4.5-Hz) geophones, spaced at 1 m. We developed both P- and S-wave tomographic velocity models, as well as Poisson's ratio and a Vp/Vs ratio models. We observed a well-defined zone of elevated Vp/Vs ratios below about 10 m depth, centered beneath the observed surface rupture. P-wave reflection images show that the fault forms a flower-structure in the upper few tens of meters. This method has been shown to delineate fault structures even in areas of rough terrain.

  13. Fault Current Characteristics of the DFIG under Asymmetrical Fault Conditions

    Directory of Open Access Journals (Sweden)

    Fan Xiao

    2015-09-01

    Full Text Available During non-severe fault conditions, crowbar protection is not activated and the rotor windings of a doubly-fed induction generator (DFIG are excited by the AC/DC/AC converter. Meanwhile, under asymmetrical fault conditions, the electrical variables oscillate at twice the grid frequency in synchronous dq frame. In the engineering practice, notch filters are usually used to extract the positive and negative sequence components. In these cases, the dynamic response of a rotor-side converter (RSC and the notch filters have a large influence on the fault current characteristics of the DFIG. In this paper, the influence of the notch filters on the proportional integral (PI parameters is discussed and the simplified calculation models of the rotor current are established. Then, the dynamic performance of the stator flux linkage under asymmetrical fault conditions is also analyzed. Based on this, the fault characteristics of the stator current under asymmetrical fault conditions are studied and the corresponding analytical expressions of the stator fault current are obtained. Finally, digital simulation results validate the analytical results. The research results are helpful to meet the requirements of a practical short-circuit calculation and the construction of a relaying protection system for the power grid with penetration of DFIGs.

  14. Faults survey by 3D reflection seismics; Sanjigen hanshaho jishin tansa ni yoru danso chosa

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchiya, T; Ejiri, T; Yamada, N; Narita, N; Aso, H; Takano, H; Matsumura, M [Dia Consultants Company, Tokyo (Japan)

    1996-10-01

    This paper describes fault survey by 3D seismic reflection exploration. Survey has been conducted mainly at flat land area without pavement not in urban area in Japan. Subsurface structure is complicated with intersecting multiple faults. In this area, a lot of geological investigations have been done prior to the seismic reflection exploration. Fairly certain images of faults have been obtained. However, there were still unknown structures. Survey was conducted at an area of 170m{times}280m in the CDP range. Measurements were carried out by using 100 g of dynamite per seismic generation point combined with 40 Hz velocity geophones. Fixed distribution consisting of lattice points of 12{times}12 was adopted as an observation method. In and around the lattice, a great number of explosions were carried out. The CDP stacking method and the method of migration after stacking were used for the data processing. The 3D structures of six horizons and five faults could be interpreted. Interpreted horizons were well agreed with the logging results. 3 figs.

  15. Low-Frequency Earthquakes Associated with the Late-Interseismic Central Alpine Fault, Southern Alps, New Zealand

    Science.gov (United States)

    Baratin, L. M.; Chamberlain, C. J.; Townend, J.; Savage, M. K.

    2016-12-01

    Characterising the seismicity associated with slow deformation in the vicinity of the Alpine Fault may provide constraints on the state of stress of this major transpressive margin prior to a large (≥M8) earthquake. Here, we use recently detected tremor and low-frequency earthquakes (LFEs) to examine how slow tectonic deformation is loading the Alpine Fault toward an anticipated large rupture. We initially work with a continous seismic dataset collected between 2009 and 2012 from an array of short-period seismometers, the Southern Alps Microearthquake Borehole Array. Fourteen primary LFE templates are used in an iterative matched-filter and stacking routine. This method allows the detection of similar signals and establishes LFE families with common locations. We thus generate a 36 month catalogue of 10718 LFEs. The detections are then combined for each LFE family using phase-weighted stacking to yield a signal with the highest possible signal to noise ratio. We found phase-weighted stacking to be successful in increasing the number of LFE detections by roughly 20%. Phase-weighted stacking also provides cleaner phase arrivals of apparently impulsive nature allowing more precise phase and polarity picks. We then compute improved non-linear earthquake locations using a 3D velocity model. We find LFEs to occur below the seismogenic zone at depths of 18-34 km, locating on or near the proposed deep extent of the Alpine Fault. Our next step is to estimate seismic source parameters by implementing a moment tensor inversion technique. Our focus is currently on generating a more extensive catalogue (spanning the years 2009 to 2016) using synthetic waveforms as primary templates, with which to detect LFEs. Initial testing shows that this technique paired up with phase-weighted stacking increases the number of LFE families and overall detected events roughly sevenfold. This catalogue should provide new insight into the geometry of the Alpine Fault and the prevailing stress

  16. Arc fault detection system

    Science.gov (United States)

    Jha, K.N.

    1999-05-18

    An arc fault detection system for use on ungrounded or high-resistance-grounded power distribution systems is provided which can be retrofitted outside electrical switchboard circuits having limited space constraints. The system includes a differential current relay that senses a current differential between current flowing from secondary windings located in a current transformer coupled to a power supply side of a switchboard, and a total current induced in secondary windings coupled to a load side of the switchboard. When such a current differential is experienced, a current travels through a operating coil of the differential current relay, which in turn opens an upstream circuit breaker located between the switchboard and a power supply to remove the supply of power to the switchboard. 1 fig.

  17. Arc fault detection system

    Science.gov (United States)

    Jha, Kamal N.

    1999-01-01

    An arc fault detection system for use on ungrounded or high-resistance-grounded power distribution systems is provided which can be retrofitted outside electrical switchboard circuits having limited space constraints. The system includes a differential current relay that senses a current differential between current flowing from secondary windings located in a current transformer coupled to a power supply side of a switchboard, and a total current induced in secondary windings coupled to a load side of the switchboard. When such a current differential is experienced, a current travels through a operating coil of the differential current relay, which in turn opens an upstream circuit breaker located between the switchboard and a power supply to remove the supply of power to the switchboard.

  18. Probabilistic assessment of faults

    International Nuclear Information System (INIS)

    Foden, R.W.

    1987-01-01

    Probabilistic safety analysis (PSA) is the process by which the probability (or frequency of occurrence) of reactor fault conditions which could lead to unacceptable consequences is assessed. The basic objective of a PSA is to allow a judgement to be made as to whether or not the principal probabilistic requirement is satisfied. It also gives insights into the reliability of the plant which can be used to identify possible improvements. This is explained in the article. The scope of a PSA and the PSA performed by the National Nuclear Corporation (NNC) for the Heysham II and Torness AGRs and Sizewell-B PWR are discussed. The NNC methods for hazards, common cause failure and operator error are mentioned. (UK)

  19. A Deep Learning Approach for Fault Diagnosis of Induction Motors in Manufacturing

    Science.gov (United States)

    Shao, Si-Yu; Sun, Wen-Jun; Yan, Ru-Qiang; Wang, Peng; Gao, Robert X.

    2017-11-01

    Extracting features from original signals is a key procedure for traditional fault diagnosis of induction motors, as it directly influences the performance of fault recognition. However, high quality features need expert knowledge and human intervention. In this paper, a deep learning approach based on deep belief networks (DBN) is developed to learn features from frequency distribution of vibration signals with the purpose of characterizing working status of induction motors. It combines feature extraction procedure with classification task together to achieve automated and intelligent fault diagnosis. The DBN model is built by stacking multiple-units of restricted Boltzmann machine (RBM), and is trained using layer-by-layer pre-training algorithm. Compared with traditional diagnostic approaches where feature extraction is needed, the presented approach has the ability of learning hierarchical representations, which are suitable for fault classification, directly from frequency distribution of the measurement data. The structure of the DBN model is investigated as the scale and depth of the DBN architecture directly affect its classification performance. Experimental study conducted on a machine fault simulator verifies the effectiveness of the deep learning approach for fault diagnosis of induction motors. This research proposes an intelligent diagnosis method for induction motor which utilizes deep learning model to automatically learn features from sensor data and realize working status recognition.

  20. Computerized plutonium laboratory-stack monitoring system

    International Nuclear Information System (INIS)

    Stafford, R.G.; DeVore, R.K.

    1977-01-01

    The Los Alamos Scientific Laboratory has recently designed and constructed a Plutonium Research and Development Facility to meet design criteria imposed by the United States Energy Research and Development Administration. A primary objective of the design criteria is to assure environmental protection and to reliably monitor plutonium effluent via the ventilation exhaust systems. A state-of-the-art facility exhaust air monitoring system is described which establishes near ideal conditions for evaluating plutonium activity in the stack effluent. Total and static pressure sensing manifolds are incorporated to measure average velocity and integrated total discharge air volume. These data are logged at a computer which receives instrument data through a multiplex scanning system. A multipoint isokinetic sampling assembly with associated instrumentation is described. Continuous air monitors have been designed to sample from the isokinetic sampling assembly and transmit both instantaneous and integrated stack effluent concentration data to the computer and various cathode ray tube displays. The continuous air monitors also serve as room air monitors in the plutonium facility with the primary objective of timely evacuation of personnel if an above tolerance airborne plutonium concentration is detected. Several continuous air monitors are incorporated in the ventilation system to assist in identification of release problem areas

  1. Control of heteroepitaxial stacking by substrate miscut

    International Nuclear Information System (INIS)

    Bonham, S.W.; Flynn, C.P.

    1998-01-01

    We report studies of fcc epitaxial crystals, grown on Nb(110), in which the Nb surface offers a template for selection between the two alternative stackings, ABCA hor-ellipsis and ACBA hor-ellipsis of the fcc close-packed planes. The Nb templates were grown epitaxially about 500 Angstrom thick on sapphire (11 bar 20), and the fcc material studied was Cu 3 Au. From symmetry it is not possible for the perfect bcc (110) surface to cause any such selection, which is here attributed instead to vicinal miscut: the logarithm of the stacking ratio must be even in miscut along [001] and odd in miscut along [1 bar 10]. We find that the measured selectivity is small for miscuts less than about 0.5 degree, but approaches a factor 10 3 for miscuts along [1 bar 10] greater than about 1 degree. A mechanism for the selection process is discussed in terms of fingered mesostructures that grow on Nb(110) in this regime, as observed first by Zhou, Bonham, and Flynn. copyright 1998 The American Physical Society

  2. Influence of faults on groundwater flow and transport at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Cohen, Andrew J.B.; Sitar, Nicholas

    1999-01-01

    Numerical simulations of groundwater flow at Yucca Mountain, Nevada are used to investigate how faults influence groundwater flow pathways and regional-scale macrodispersion. The 3-D model has a unique grid block discretization that facilitates the accurate representation of the complex geologic structure present in faulted formations. Each hydrogeologic layer is discretized into a single layer of irregular and dipping grid blocks, and faults are discretized such that they are laterally continuous and varied in displacement varies along strike. In addition, the presence of altered fault zones is explicitly modeled, as appropriate. Simulations show that upward head gradients can be readily explained by the geometry of hydrogeologic layers, the variability of layer permeabilities, and the presence of permeable fault zones or faults with displacement only, not necessarily by upwelling from a deep aquifer. Large-scale macrodispersion results from the vertical and lateral diversion of flow near the contact of high- and low-permeability layers at faults, and from upward flow within high-permeability fault zones. Conversely, large-scale channeling can occur as a result of groundwater flow into areas with minimal fault displacement. Contaminants originating at the water table can flow in a direction significantly different from that of the water table gradient, and isolated zones of contaminants can occur at the water table downgradient. By conducting both 2-D and 3-D simulations, we show that the 2-D cross-sectional models traditionally used to examine flow in faulted formations may not be appropriate. In addition, the influence of a particular type of fault cannot be generalized; depending on the location where contaminants enter the saturated zone, faults may either enhance or inhibit vertical dispersion

  3. Evaluation of field emission properties from multiple-stacked Si quantum dots

    International Nuclear Information System (INIS)

    Takeuchi, Daichi; Makihara, Katsunori; Ohta, Akio; Ikeda, Mitsuhisa; Miyazaki, Seiichi

    2016-01-01

    Multiple-stacked Si quantum dots (QDs) with ultrathin SiO 2 interlayers were formed on ultrathin SiO 2 layers by repeating a process sequence consisting of the formation of Si-QDs by low pressure chemical vapor deposition using a SiH 4 gas and the surface oxidation and subsequent surface modification by remote hydrogen and oxygen plasmas, respectively. To clarify the electron emission mechanism from multiple-stacked Si-QDs covered with an ultrathin Au top electrode, the energy distribution of the emitted electrons and its electric field dependence was measured using a hemispherical electron energy analyzer in an X-ray photoelectron spectroscopy system under DC bias application to the multiple-stacked Si-QD structure. At − 6 V and over, the energy distributions reached a peak at ~ 2.5 eV with a tail toward the higher energy side. While the electron emission intensity was increased exponentially with an increase in the applied DC bias, there was no significant increase in the emission peak energy. The observed emission characteristics can be interpreted in terms of field emissions from the second and/or third topmost Si-QDs resulting from the electric concentration there. - Highlights: • Electron field emission from 6-fold stack of Si-QDs has been evaluated. • AFM measurements show the local electron emission from individual Si-QDs. • Impact of applied bias on the electron emission energy distribution was investigated.

  4. Meteoric water in normal fault systems: Oxygen and hydrogen isotopic measurements on authigenic phases in brittle fault rocks

    Science.gov (United States)

    Haines, S. H.; Anderson, R.; Mulch, A.; Solum, J. G.; Valley, J. W.; van der Pluijm, B. A.

    2009-12-01

    The nature of fluid circulation systems in normal fault systems is fundamental to understanding the nature of fluid movement within the upper crust, and has important implications for the on-going controversy about the strength of faults. Authigenic phases in clay gouges and fault breccias record the isotopic signature of the fluids they formed in equilibrium with, and can be used to understand the ‘plumbing system’ of brittle fault environments. We obtained paired oxygen and hydrogen isotopic measurements on authigenic illite and/or smectite in clay gouge from normal faults in two geologic environments, 1.) low-angle normal faults (Ruby Mountains detachment, NV; Badwater Turtleback, CA; Panamint range-front detachment; CA; Amargosa detachment; CA; Waterman Hills detachment, CA), and 2.) An intracratonic high-angle normal fault (Moab Fault, UT). All authigenic phases in these clay gouges are moderately light isotopically with respect to oxygen (illite δ18O -2.0 - + 11.5 ‰ SMOW, smectite δ18O +3.6 and 17.9 ‰) and very light isotopically with respect to hydrogen (illite δD -148 to -98 ‰ SMOW, smectite δD -147 to -92 ‰). Fluid compositions calculated from the authigenic clays at temperatures of 50 - 130 ○C (as indicated by clay mineralogy) indicate that both illite and smectite in normal fault clay gouge formed in the presence of near-pristine to moderately-evolved meteoric fluids and that igneous or metamorphic fluids are not involved in clay gouge formation in these normal fault settings. We also obtained paired oxygen and hydrogen isotopic measurements on chlorites derived from footwall chlorite breccias in 4 low-angle normal fault detachment systems (Badwater and Mormon Point Turtlebacks, CA, the Chemehuevi detachment, CA, and the Buckskin-Rawhide detachment, AZ). All chlorites are isotopically light to moderately light with respect to oxygen (δ18O +0.29 to +8.1 ‰ SMOW) and very light with respect to hydrogen (δD -97 to -113 ‰) and indicate

  5. Absolute age determination of quaternary faults

    International Nuclear Information System (INIS)

    Cheong, Chang Sik; Lee, Seok Hoon; Choi, Man Sik

    2000-03-01

    To constrain the age of neotectonic fault movement, Rb-Sr, K-Ar, U-series disequilibrium, C-14 and Be-10 methods were applied to the fault gouges, fracture infillings and sediments from the Malbang, Ipsil, Wonwonsa faults faults in the Ulsan fault zone, Yangsan fault in the Yeongdeog area and southeastern coastal area. Rb-Sr and K-Ar data imply that the fault movement of the Ulan fault zone initiated at around 30 Ma and preliminary dating result for the Yang san fault is around 70 Ma in the Yeongdeog area. K-Ar and U-series disequilibrium dating results for fracture infillings in the Ipsil fault are consistent with reported ESR ages. Radiocarbon ages of quaternary sediments from the Jeongjari area are discordant with stratigraphic sequence. Carbon isotope data indicate a difference of sedimentry environment for those samples. Be-10 dating results for the Suryum fault area are consistent with reported OSL results

  6. Absolute age determination of quaternary faults

    Energy Technology Data Exchange (ETDEWEB)

    Cheong, Chang Sik; Lee, Seok Hoon; Choi, Man Sik [Korea Basic Science Institute, Seoul (Korea, Republic of)] (and others)

    2000-03-15

    To constrain the age of neotectonic fault movement, Rb-Sr, K-Ar, U-series disequilibrium, C-14 and Be-10 methods were applied to the fault gouges, fracture infillings and sediments from the Malbang, Ipsil, Wonwonsa faults faults in the Ulsan fault zone, Yangsan fault in the Yeongdeog area and southeastern coastal area. Rb-Sr and K-Ar data imply that the fault movement of the Ulan fault zone initiated at around 30 Ma and preliminary dating result for the Yang san fault is around 70 Ma in the Yeongdeog area. K-Ar and U-series disequilibrium dating results for fracture infillings in the Ipsil fault are consistent with reported ESR ages. Radiocarbon ages of quaternary sediments from the Jeongjari area are discordant with stratigraphic sequence. Carbon isotope data indicate a difference of sedimentry environment for those samples. Be-10 dating results for the Suryum fault area are consistent with reported OSL results.

  7. Comparison of Cenozoic Faulting at the Savannah River Site to Fault Characteristics of the Atlantic Coast Fault Province: Implications for Fault Capability

    International Nuclear Information System (INIS)

    Cumbest, R.J.

    2000-01-01

    This study compares the faulting observed on the Savannah River Site and vicinity with the faults of the Atlantic Coastal Fault Province and concludes that both sets of faults exhibit the same general characteristics and are closely associated. Based on the strength of this association it is concluded that the faults observed on the Savannah River Site and vicinity are in fact part of the Atlantic Coastal Fault Province. Inclusion in this group means that the historical precedent established by decades of previous studies on the seismic hazard potential for the Atlantic Coastal Fault Province is relevant to faulting at the Savannah River Site. That is, since these faults are genetically related the conclusion of ''not capable'' reached in past evaluations applies.In addition, this study establishes a set of criteria by which individual faults may be evaluated in order to assess their inclusion in the Atlantic Coast Fault Province and the related association of the ''not capable'' conclusion

  8. Description of gasket failure in a 7 cell PEMFC stack

    Energy Technology Data Exchange (ETDEWEB)

    Husar, Attila; Serra, Maria [Institut de Robotica i Informatica Industrial, Parc Tecnologic de Barcelona, Edifici U, C. Llorens i Artigas, 4-6, 2a Planta, 08028 Barcelona (Spain); Kunusch, Cristian [Laboratorio de Electronica Industrial Control e Instrumentacion, Facultad de Ingenieria, UNLP (Argentina)

    2007-06-10

    This article presents the data and the description of a fuel cell stack that failed due to gasket degradation. The fuel cell under study is a 7 cell stack. The unexpected change in several variables such as temperature, pressure and voltage indicated the possible failure of the stack. The stack was monitored over a 6 h period in which data was collected and consequently analyzed to conclude that the fuel cell stack failed due to a crossover leak on the anode inlet port located on the cathode side gasket of cell 2. This stack failure analysis revealed a series of indicators that could be used by a super visional controller in order to initiate a shutdown procedure. (author)

  9. Simple Stacking Methods for Silicon Micro Fuel Cells

    Directory of Open Access Journals (Sweden)

    Gianmario Scotti

    2014-08-01

    Full Text Available We present two simple methods, with parallel and serial gas flows, for the stacking of microfabricated silicon fuel cells with integrated current collectors, flow fields and gas diffusion layers. The gas diffusion layer is implemented using black silicon. In the two stacking methods proposed in this work, the fluidic apertures and gas flow topology are rotationally symmetric and enable us to stack fuel cells without an increase in the number of electrical or fluidic ports or interconnects. Thanks to this simplicity and the structural compactness of each cell, the obtained stacks are very thin (~1.6 mm for a two-cell stack. We have fabricated two-cell stacks with two different gas flow topologies and obtained an open-circuit voltage (OCV of 1.6 V and a power density of 63 mW·cm−2, proving the viability of the design.

  10. Subaru FATS (fault tracking system)

    Science.gov (United States)

    Winegar, Tom W.; Noumaru, Junichi

    2000-07-01

    The Subaru Telescope requires a fault tracking system to record the problems and questions that staff experience during their work, and the solutions provided by technical experts to these problems and questions. The system records each fault and routes it to a pre-selected 'solution-provider' for each type of fault. The solution provider analyzes the fault and writes a solution that is routed back to the fault reporter and recorded in a 'knowledge-base' for future reference. The specifications of our fault tracking system were unique. (1) Dual language capacity -- Our staff speak both English and Japanese. Our contractors speak Japanese. (2) Heterogeneous computers -- Our computer workstations are a mixture of SPARCstations, Macintosh and Windows computers. (3) Integration with prime contractors -- Mitsubishi and Fujitsu are primary contractors in the construction of the telescope. In many cases, our 'experts' are our contractors. (4) Operator scheduling -- Our operators spend 50% of their work-month operating the telescope, the other 50% is spent working day shift at the base facility in Hilo, or day shift at the summit. We plan for 8 operators, with a frequent rotation. We need to keep all operators informed on the current status of all faults, no matter the operator's location.

  11. Development of the electric utility dispersed use PAFC stack

    Energy Technology Data Exchange (ETDEWEB)

    Horiuchi, Hiroshi; Kotani, Ikuo [Mitsubishi Electric Co., Kobe (Japan); Morotomi, Isamu [Kansai Electric Power Co., Hyogo (Japan)] [and others

    1996-12-31

    Kansai Electric Power Co. and Mitsubishi Electric Co. have been developing the electric utility dispersed use PAFC stack operated under the ambient pressure. The new cell design have been developed, so that the large scale cell (1 m{sup 2} size) was adopted for the stack. To confirm the performance and the stability of the 1 m{sup 2} scale cell design, the short stack study had been performed.

  12. Stacked Heterogeneous Neural Networks for Time Series Forecasting

    Directory of Open Access Journals (Sweden)

    Florin Leon

    2010-01-01

    Full Text Available A hybrid model for time series forecasting is proposed. It is a stacked neural network, containing one normal multilayer perceptron with bipolar sigmoid activation functions, and the other with an exponential activation function in the output layer. As shown by the case studies, the proposed stacked hybrid neural model performs well on a variety of benchmark time series. The combination of weights of the two stack components that leads to optimal performance is also studied.

  13. Why the 2002 Denali fault rupture propagated onto the Totschunda fault: implications for fault branching and seismic hazards

    Science.gov (United States)

    Schwartz, David P.; Haeussler, Peter J.; Seitz, Gordon G.; Dawson, Timothy E.

    2012-01-01

    The propagation of the rupture of the Mw7.9 Denali fault earthquake from the central Denali fault onto the Totschunda fault has provided a basis for dynamic models of fault branching in which the angle of the regional or local prestress relative to the orientation of the main fault and branch plays a principal role in determining which fault branch is taken. GeoEarthScope LiDAR and paleoseismic data allow us to map the structure of the Denali-Totschunda fault intersection and evaluate controls of fault branching from a geological perspective. LiDAR data reveal the Denali-Totschunda fault intersection is structurally simple with the two faults directly connected. At the branch point, 227.2 km east of the 2002 epicenter, the 2002 rupture diverges southeast to become the Totschunda fault. We use paleoseismic data to propose that differences in the accumulated strain on each fault segment, which express differences in the elapsed time since the most recent event, was one important control of the branching direction. We suggest that data on event history, slip rate, paleo offsets, fault geometry and structure, and connectivity, especially on high slip rate-short recurrence interval faults, can be used to assess the likelihood of branching and its direction. Analysis of the Denali-Totschunda fault intersection has implications for evaluating the potential for a rupture to propagate across other types of fault intersections and for characterizing sources of future large earthquakes.

  14. Architecture of thrust faults with alongstrike variations in fault-plane dip: anatomy of the Lusatian Fault, Bohemian Massif

    Czech Academy of Sciences Publication Activity Database

    Coubal, Miroslav; Adamovič, Jiří; Málek, Jiří; Prouza, V.

    2014-01-01

    Roč. 59, č. 3 (2014), s. 183-208 ISSN 1802-6222 Institutional support: RVO:67985831 ; RVO:67985891 Keywords : fault architecture * fault plane geometry * drag structures * thrust fault * sandstone * Lusatian Fault Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.405, year: 2014

  15. Turbostratic stacked CVD graphene for high-performance devices

    Science.gov (United States)

    Uemura, Kohei; Ikuta, Takashi; Maehashi, Kenzo

    2018-03-01

    We have fabricated turbostratic stacked graphene with high-transport properties by the repeated transfer of CVD monolayer graphene. The turbostratic stacked CVD graphene exhibited higher carrier mobility and conductivity than CVD monolayer graphene. The electron mobility for the three-layer turbostratic stacked CVD graphene surpassed 10,000 cm2 V-1 s-1 at room temperature, which is five times greater than that for CVD monolayer graphene. The results indicate that the high performance is derived from maintenance of the linear band dispersion, suppression of the carrier scattering, and parallel conduction. Therefore, turbostratic stacked CVD graphene is a superior material for high-performance devices.

  16. Method for monitoring stack gases for uranium activity

    International Nuclear Information System (INIS)

    Beverly, C.R.; Ernstberger, H.G.

    1988-01-01

    A method for sampling stack gases emanating from the purge cascade of a gaseous diffusion cascade system utilized to enrich uranium for determining the presence and extent of uranium in the stack gases in the form of gaseous uranium hexafluoride, is described comprising the steps of removing a side stream of gases from the stack gases, contacting the side stream of the stack gases with a stream of air sufficiently saturated with moisture for reacting with and converting any gaseous uranium hexafluroide contracted thereby in the side stream of stack gases to particulate uranyl fluoride. Thereafter contacting the side stream of stack gases containing the particulate uranyl fluoride with moving filter means for continuously intercepting and conveying the intercepted particulate uranyl fluoride away from the side stream of stack gases, and continually scanning the moving filter means with radiation monitoring means for sensing the presence and extent of particulate uranyl fluoride on the moving filter means which is indicative of the extent of particulate uranyl fluoride in the side stream of stack gases which in turn is indicative of the presence and extent of uranium hexafluoride in the stack gases

  17. Highly Efficient, Durable Regenerative Solid Oxide Stack, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Precision Combustion, Inc. (PCI) proposes to develop a highly efficient regenerative solid oxide stack design. Novel structural elements allow direct internal...

  18. Fault Features Extraction and Identification based Rolling Bearing Fault Diagnosis

    International Nuclear Information System (INIS)

    Qin, B; Sun, G D; Zhang L Y; Wang J G; HU, J

    2017-01-01

    For the fault classification model based on extreme learning machine (ELM), the diagnosis accuracy and stability of rolling bearing is greatly influenced by a critical parameter, which is the number of nodes in hidden layer of ELM. An adaptive adjustment strategy is proposed based on vibrational mode decomposition, permutation entropy, and nuclear kernel extreme learning machine to determine the tunable parameter. First, the vibration signals are measured and then decomposed into different fault feature models based on variation mode decomposition. Then, fault feature of each model is formed to a high dimensional feature vector set based on permutation entropy. Second, the ELM output function is expressed by the inner product of Gauss kernel function to adaptively determine the number of hidden layer nodes. Finally, the high dimension feature vector set is used as the input to establish the kernel ELM rolling bearing fault classification model, and the classification and identification of different fault states of rolling bearings are carried out. In comparison with the fault classification methods based on support vector machine and ELM, the experimental results show that the proposed method has higher classification accuracy and better generalization ability. (paper)

  19. Neutron diffraction study of the formation of ordered antiphase domains in cubic titanium carbide TiC0.60

    International Nuclear Information System (INIS)

    Khidirov, I.; Parpiev, A. S.

    2013-01-01

    A series of superstructural reflections (described within the sp. gr. Fd3m) are found to be split into three symmetric parts in the neutron powder diffraction pattern of titanium carbide TiC 0.60 annealed at a temperature of 600°C. No splitting of superstructural reflections is observed in the neutron diffraction pattern of TiC 0.60 annealed at relatively high temperatures (780°C). This phenomenon can be explained by that fact that the ordering of carbon atoms at relatively high temperatures (780°C) is accompanied by the formation of randomly oriented rather large antiphase domains (APDs) (450 Å). At relatively low temperatures (600°C), stacking faults arise in the arrangement of partially ordered carbon atoms. In this case, relatively small ordered APDs (290 Å) are formed, along with disordered ones.

  20. Durable solid oxide electrolysis cells and stacks

    Energy Technology Data Exchange (ETDEWEB)

    Ming Chen

    2010-08-15

    The purpose of this project was to make a substantial contribution to development of a cost competitive electrolysis technology based on solid oxide cells. The strategy was to address what had been identified as the key issues in previous research projects. Accordingly five lines of work were carried out in the here reported project: 1) Cell and stack element testing and post test characterization to identify major degradation mechanisms under electrolysis operation. 2) Development of interconnects and coatings to allow stable electrolysis operation at approx850 deg. C or above. 3) Development of seals with reduced Si emission. 4) Development of durable SOEC cathodes. 5) Modeling. Good progress has been made on several of the planned activities. The outcome and most important achievements of the current project are listed for the five lines of the work. (LN)